[llvm] 1506e4c - [DWARFLinkerParallel] Add limited functionality to DWARFLinkerParallel.

Alexey Lapshin via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 17 00:49:17 PDT 2023


Author: Alexey Lapshin
Date: 2023-08-17T09:47:34+02:00
New Revision: 1506e4c77624aa3d208658fd356b9caccc1a713f

URL: https://github.com/llvm/llvm-project/commit/1506e4c77624aa3d208658fd356b9caccc1a713f
DIFF: https://github.com/llvm/llvm-project/commit/1506e4c77624aa3d208658fd356b9caccc1a713f.diff

LOG: [DWARFLinkerParallel] Add limited functionality to DWARFLinkerParallel.

This patch is extracted from D96035, it adds support for the existing
DWARFLinker functionality. What is not supported yet:

1. Types deduplication(--odr mode).
2. Modules deduplication.
3. Generation of index tables.

Differential Revision: https://reviews.llvm.org/D153268

Added: 
    llvm/lib/DWARFLinkerParallel/ArrayList.h
    llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.cpp
    llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.h
    llvm/lib/DWARFLinkerParallel/DIEGenerator.h
    llvm/lib/DWARFLinkerParallel/DWARFFile.cpp
    llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.cpp
    llvm/lib/DWARFLinkerParallel/DWARFLinkerGlobalData.h
    llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.cpp
    llvm/lib/DWARFLinkerParallel/DebugLineSectionEmitter.h
    llvm/lib/DWARFLinkerParallel/DependencyTracker.cpp
    llvm/lib/DWARFLinkerParallel/DependencyTracker.h
    llvm/lib/DWARFLinkerParallel/IndexedValuesMap.h
    llvm/lib/DWARFLinkerParallel/StringEntryToDwarfStringPoolEntryMap.h
    llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-dwarf4-combination-macho.test
    llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-macho.test
    llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/fat-dylib-update.test
    llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/obfuscated.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-bundle.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-dw4-linking-x86.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-linking-x86.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-with-libfat-test.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/empty_range.s
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-1.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-2.test
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/multiple-inputs.test

Modified: 
    llvm/include/llvm/CodeGen/DwarfStringPoolEntry.h
    llvm/include/llvm/DWARFLinker/DWARFLinker.h
    llvm/include/llvm/DWARFLinkerParallel/AddressesMap.h
    llvm/include/llvm/DWARFLinkerParallel/DWARFFile.h
    llvm/include/llvm/DWARFLinkerParallel/StringPool.h
    llvm/include/llvm/DebugInfo/DWARF/DWARFDebugMacro.h
    llvm/lib/DWARFLinker/DWARFLinker.cpp
    llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
    llvm/lib/DWARFLinkerParallel/CMakeLists.txt
    llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.cpp
    llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.h
    llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.h
    llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.cpp
    llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.h
    llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.h
    llvm/lib/DWARFLinkerParallel/OutputSections.cpp
    llvm/lib/DWARFLinkerParallel/OutputSections.h
    llvm/test/tools/dsymutil/ARM/call-pc-reloc.test
    llvm/test/tools/dsymutil/ARM/dwarf5-addr-base.test
    llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test
    llvm/test/tools/dsymutil/ARM/dwarf5-str-offsets-base-strx.test
    llvm/test/tools/dsymutil/ARM/empty-map.test
    llvm/test/tools/dsymutil/ARM/extern-alias.test
    llvm/test/tools/dsymutil/ARM/fat-arch-name.test
    llvm/test/tools/dsymutil/ARM/fat-arch-not-found.test
    llvm/test/tools/dsymutil/ARM/inlined-low_pc.c
    llvm/test/tools/dsymutil/ARM/preload.test
    llvm/test/tools/dsymutil/ARM/scattered.c
    llvm/test/tools/dsymutil/ARM/thumb.c
    llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-x86.test
    llvm/test/tools/dsymutil/X86/alias.test
    llvm/test/tools/dsymutil/X86/call-site-entry-linking.test
    llvm/test/tools/dsymutil/X86/call-site-entry-reloc.test
    llvm/test/tools/dsymutil/X86/common-sym-multi.test
    llvm/test/tools/dsymutil/X86/common-sym.test
    llvm/test/tools/dsymutil/X86/custom-line-table.test
    llvm/test/tools/dsymutil/X86/darwin-bundle.test
    llvm/test/tools/dsymutil/X86/dead-stripped.cpp
    llvm/test/tools/dsymutil/X86/debug-loc-base-addr.test
    llvm/test/tools/dsymutil/X86/dwarf4-linetable.test
    llvm/test/tools/dsymutil/X86/dwarf5-addrx.test
    llvm/test/tools/dsymutil/X86/dwarf5-call-site-entry-reloc.test
    llvm/test/tools/dsymutil/X86/dwarf5-dw-op-addrx.test
    llvm/test/tools/dsymutil/X86/dwarf5-linetable.test
    llvm/test/tools/dsymutil/X86/dwarf5-loclists.test
    llvm/test/tools/dsymutil/X86/dwarf5-rnglists.test
    llvm/test/tools/dsymutil/X86/eh_frame.test
    llvm/test/tools/dsymutil/X86/empty-CU.test
    llvm/test/tools/dsymutil/X86/fat-archive-input-i386.test
    llvm/test/tools/dsymutil/X86/fat-object-input-x86_64.test
    llvm/test/tools/dsymutil/X86/fat-object-input-x86_64h.test
    llvm/test/tools/dsymutil/X86/generate-empty-CU.test
    llvm/test/tools/dsymutil/X86/global_downgraded_to_static.c
    llvm/test/tools/dsymutil/X86/inlined-static-variable.cpp
    llvm/test/tools/dsymutil/X86/keep-func.test
    llvm/test/tools/dsymutil/X86/label.test
    llvm/test/tools/dsymutil/X86/label2.test
    llvm/test/tools/dsymutil/X86/lc_build_version.test
    llvm/test/tools/dsymutil/X86/location-expression.test
    llvm/test/tools/dsymutil/X86/mismatch.m
    llvm/test/tools/dsymutil/X86/modules-dwarf-version.m
    llvm/test/tools/dsymutil/X86/modules-empty.m
    llvm/test/tools/dsymutil/X86/multiple-inputs.test
    llvm/test/tools/dsymutil/X86/object-prefix-path.test
    llvm/test/tools/dsymutil/X86/op-convert-offset.test
    llvm/test/tools/dsymutil/X86/op-convert.test
    llvm/test/tools/dsymutil/X86/papertrail-warnings.test
    llvm/test/tools/dsymutil/X86/reflection-dump.test
    llvm/test/tools/dsymutil/X86/remarks-linking-archive.text
    llvm/test/tools/dsymutil/X86/remarks-linking-bundle-empty.test
    llvm/test/tools/dsymutil/X86/remarks-linking-bundle.test
    llvm/test/tools/dsymutil/X86/remarks-linking-fat-bundle.test
    llvm/test/tools/dsymutil/X86/reproducer.test
    llvm/test/tools/dsymutil/X86/statistics.test
    llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
    llvm/test/tools/dsymutil/X86/swift-dwarf-loc.test
    llvm/test/tools/dsymutil/X86/tail-call-linking.test
    llvm/test/tools/dsymutil/X86/thinlto.test
    llvm/test/tools/dsymutil/X86/timestamp-mismatch.test
    llvm/test/tools/dsymutil/X86/tls-variable.test
    llvm/test/tools/dsymutil/X86/union-fwd-decl.test
    llvm/test/tools/dsymutil/X86/verify.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro-short.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-addresses.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-attributes.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-line-str.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-loclists.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-opcodeop.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-short.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-rnglists.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-default.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-func-overlapping-address-ranges.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-maxpc.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-no-garbage.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-unit-overlapping-address-ranges.test
    llvm/test/tools/llvm-dwarfutil/ELF/X86/verify.test
    llvm/tools/dsymutil/BinaryHolder.cpp
    llvm/tools/dsymutil/BinaryHolder.h
    llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
    llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp
    llvm/unittests/CodeGen/DwarfStringPoolEntryRefTest.cpp
    llvm/unittests/DWARFLinkerParallel/CMakeLists.txt
    llvm/unittests/DWARFLinkerParallel/StringPoolTest.cpp

Removed: 
    llvm/include/llvm/DWARFLinkerParallel/StringTable.h
    llvm/test/tools/llvm-dwarfutil/ELF/X86/DWARFLinkerParallel/gc-default.test
    llvm/unittests/DWARFLinkerParallel/StringTableTest.cpp


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/DwarfStringPoolEntry.h b/llvm/include/llvm/CodeGen/DwarfStringPoolEntry.h
index 7822ebf2eb0999..188dfbe790e2ce 100644
--- a/llvm/include/llvm/CodeGen/DwarfStringPoolEntry.h
+++ b/llvm/include/llvm/CodeGen/DwarfStringPoolEntry.h
@@ -27,29 +27,34 @@ struct DwarfStringPoolEntry {
   bool isIndexed() const { return Index != NotIndexed; }
 };
 
+/// DwarfStringPoolEntry with string keeping externally.
+struct DwarfStringPoolEntryWithExtString : public DwarfStringPoolEntry {
+  StringRef String;
+};
+
 /// DwarfStringPoolEntryRef: Dwarf string pool entry reference.
 ///
 /// Dwarf string pool entry keeps string value and its data.
 /// There are two variants how data are represented:
 ///
-///   1. By value - StringMapEntry<DwarfStringPoolEntry>.
-///   2. By pointer - StringMapEntry<DwarfStringPoolEntry *>.
+///   1. String data in pool  - StringMapEntry<DwarfStringPoolEntry>.
+///   2. External string data - DwarfStringPoolEntryWithExtString.
 ///
-/// The "By pointer" variant allows for reducing memory usage for the case
-/// when string pool entry does not have data: it keeps the null pointer
-/// and so no need to waste space for the full DwarfStringPoolEntry.
-/// It is recommended to use "By pointer" variant if not all entries
-/// of dwarf string pool have corresponding DwarfStringPoolEntry.
+/// The external data variant allows reducing memory usage for the case
+/// when string pool entry does not have data: string entry does not
+/// keep any data and so no need to waste space for the full
+/// DwarfStringPoolEntry. It is recommended to use external variant if not all
+/// entries of dwarf string pool have corresponding DwarfStringPoolEntry.
 
 class DwarfStringPoolEntryRef {
   /// Pointer type for "By value" string entry.
   using ByValStringEntryPtr = const StringMapEntry<DwarfStringPoolEntry> *;
 
-  /// Pointer type for "By pointer" string entry.
-  using ByPtrStringEntryPtr = const StringMapEntry<DwarfStringPoolEntry *> *;
+  /// Pointer type for external string entry.
+  using ExtStringEntryPtr = const DwarfStringPoolEntryWithExtString *;
 
   /// Pointer to the dwarf string pool Entry.
-  PointerUnion<ByValStringEntryPtr, ByPtrStringEntryPtr> MapEntry = nullptr;
+  PointerUnion<ByValStringEntryPtr, ExtStringEntryPtr> MapEntry = nullptr;
 
 public:
   DwarfStringPoolEntryRef() = default;
@@ -61,10 +66,8 @@ class DwarfStringPoolEntryRef {
 
   /// ASSUMPTION: DwarfStringPoolEntryRef keeps pointer to \p Entry,
   /// thus specified entry mustn`t be reallocated.
-  DwarfStringPoolEntryRef(const StringMapEntry<DwarfStringPoolEntry *> &Entry)
-      : MapEntry(&Entry) {
-    assert(cast<ByPtrStringEntryPtr>(MapEntry)->second != nullptr);
-  }
+  DwarfStringPoolEntryRef(const DwarfStringPoolEntryWithExtString &Entry)
+      : MapEntry(&Entry) {}
 
   explicit operator bool() const { return !MapEntry.isNull(); }
 
@@ -88,7 +91,7 @@ class DwarfStringPoolEntryRef {
     if (isa<ByValStringEntryPtr>(MapEntry))
       return cast<ByValStringEntryPtr>(MapEntry)->first();
 
-    return cast<ByPtrStringEntryPtr>(MapEntry)->first();
+    return cast<ExtStringEntryPtr>(MapEntry)->String;
   }
 
   /// \returns the entire string pool entry for convenience.
@@ -96,7 +99,7 @@ class DwarfStringPoolEntryRef {
     if (isa<ByValStringEntryPtr>(MapEntry))
       return cast<ByValStringEntryPtr>(MapEntry)->second;
 
-    return *cast<ByPtrStringEntryPtr>(MapEntry)->second;
+    return *cast<ExtStringEntryPtr>(MapEntry);
   }
 
   bool operator==(const DwarfStringPoolEntryRef &X) const {

diff  --git a/llvm/include/llvm/DWARFLinker/DWARFLinker.h b/llvm/include/llvm/DWARFLinker/DWARFLinker.h
index 7a19858f426792..e615f7bbef0212 100644
--- a/llvm/include/llvm/DWARFLinker/DWARFLinker.h
+++ b/llvm/include/llvm/DWARFLinker/DWARFLinker.h
@@ -270,9 +270,11 @@ using UnitListTy = std::vector<std::unique_ptr<CompileUnit>>;
 /// and its address map.
 class DWARFFile {
 public:
+  using UnloadCallbackTy = std::function<void(StringRef FileName)>;
   DWARFFile(StringRef Name, std::unique_ptr<DWARFContext> Dwarf,
             std::unique_ptr<AddressesMap> Addresses,
-            const std::vector<std::string> &Warnings)
+            const std::vector<std::string> &Warnings,
+            UnloadCallbackTy = nullptr)
       : FileName(Name), Dwarf(std::move(Dwarf)),
         Addresses(std::move(Addresses)), Warnings(Warnings) {}
 

diff  --git a/llvm/include/llvm/DWARFLinkerParallel/AddressesMap.h b/llvm/include/llvm/DWARFLinkerParallel/AddressesMap.h
index 5d735abab419e6..22fbec20d7d376 100644
--- a/llvm/include/llvm/DWARFLinkerParallel/AddressesMap.h
+++ b/llvm/include/llvm/DWARFLinkerParallel/AddressesMap.h
@@ -10,8 +10,10 @@
 #define LLVM_DWARFLINKERPARALLEL_ADDRESSESMAP_H
 
 #include "llvm/ADT/AddressRanges.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
+#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 #include <cstdint>
 
 namespace llvm {
@@ -62,6 +64,108 @@ class AddressesMap {
 
   /// Erases all data.
   virtual void clear() = 0;
+
+  /// This function checks whether variable has DWARF expression containing
+  /// operation referencing live address(f.e. DW_OP_addr, DW_OP_addrx...).
+  /// \returns first is true if the expression has an operation referencing an
+  /// address.
+  ///          second is the relocation adjustment value if the live address is
+  ///          referenced.
+  std::pair<bool, std::optional<int64_t>>
+  getVariableRelocAdjustment(const DWARFDie &DIE) {
+    assert((DIE.getTag() == dwarf::DW_TAG_variable ||
+            DIE.getTag() == dwarf::DW_TAG_constant) &&
+           "Wrong type of input die");
+
+    const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
+
+    // Check if DIE has DW_AT_location attribute.
+    DWARFUnit *U = DIE.getDwarfUnit();
+    std::optional<uint32_t> LocationIdx =
+        Abbrev->findAttributeIndex(dwarf::DW_AT_location);
+    if (!LocationIdx)
+      return std::make_pair(false, std::nullopt);
+
+    // Get offset to the DW_AT_location attribute.
+    uint64_t AttrOffset =
+        Abbrev->getAttributeOffsetFromIndex(*LocationIdx, DIE.getOffset(), *U);
+
+    // Get value of the DW_AT_location attribute.
+    std::optional<DWARFFormValue> LocationValue =
+        Abbrev->getAttributeValueFromOffset(*LocationIdx, AttrOffset, *U);
+    if (!LocationValue)
+      return std::make_pair(false, std::nullopt);
+
+    // Check that DW_AT_location attribute is of 'exprloc' class.
+    // Handling value of location expressions for attributes of 'loclist'
+    // class is not implemented yet.
+    std::optional<ArrayRef<uint8_t>> Expr = LocationValue->getAsBlock();
+    if (!Expr)
+      return std::make_pair(false, std::nullopt);
+
+    // Parse 'exprloc' expression.
+    DataExtractor Data(toStringRef(*Expr), U->getContext().isLittleEndian(),
+                       U->getAddressByteSize());
+    DWARFExpression Expression(Data, U->getAddressByteSize(),
+                               U->getFormParams().Format);
+
+    bool HasLocationAddress = false;
+    uint64_t CurExprOffset = 0;
+    for (DWARFExpression::iterator It = Expression.begin();
+         It != Expression.end(); ++It) {
+      DWARFExpression::iterator NextIt = It;
+      ++NextIt;
+
+      const DWARFExpression::Operation &Op = *It;
+      switch (Op.getCode()) {
+      case dwarf::DW_OP_const2u:
+      case dwarf::DW_OP_const4u:
+      case dwarf::DW_OP_const8u:
+      case dwarf::DW_OP_const2s:
+      case dwarf::DW_OP_const4s:
+      case dwarf::DW_OP_const8s:
+        if (NextIt == Expression.end() || !isTlsAddressCode(NextIt->getCode()))
+          break;
+        [[fallthrough]];
+      case dwarf::DW_OP_addr: {
+        HasLocationAddress = true;
+        // Check relocation for the address.
+        if (std::optional<int64_t> RelocAdjustment =
+                getExprOpAddressRelocAdjustment(*U, Op,
+                                                AttrOffset + CurExprOffset,
+                                                AttrOffset + Op.getEndOffset()))
+          return std::make_pair(HasLocationAddress, *RelocAdjustment);
+      } break;
+      case dwarf::DW_OP_constx:
+      case dwarf::DW_OP_addrx: {
+        HasLocationAddress = true;
+        if (std::optional<uint64_t> AddressOffset =
+                DIE.getDwarfUnit()->getIndexedAddressOffset(
+                    Op.getRawOperand(0))) {
+          // Check relocation for the address.
+          if (std::optional<int64_t> RelocAdjustment =
+                  getExprOpAddressRelocAdjustment(
+                      *U, Op, *AddressOffset,
+                      *AddressOffset +
+                          DIE.getDwarfUnit()->getAddressByteSize()))
+            return std::make_pair(HasLocationAddress, *RelocAdjustment);
+        }
+      } break;
+      default: {
+        // Nothing to do.
+      } break;
+      }
+      CurExprOffset = Op.getEndOffset();
+    }
+
+    return std::make_pair(HasLocationAddress, std::nullopt);
+  }
+
+protected:
+  inline bool isTlsAddressCode(uint8_t DW_OP_Code) {
+    return DW_OP_Code == dwarf::DW_OP_form_tls_address ||
+           DW_OP_Code == dwarf::DW_OP_GNU_push_tls_address;
+  }
 };
 
 } // end of namespace dwarflinker_parallel

diff  --git a/llvm/include/llvm/DWARFLinkerParallel/DWARFFile.h b/llvm/include/llvm/DWARFLinkerParallel/DWARFFile.h
index c20d59f9771d9d..e48150ef2339e2 100644
--- a/llvm/include/llvm/DWARFLinkerParallel/DWARFFile.h
+++ b/llvm/include/llvm/DWARFLinkerParallel/DWARFFile.h
@@ -30,14 +30,7 @@ class DWARFFile {
   DWARFFile(StringRef Name, std::unique_ptr<DWARFContext> Dwarf,
             std::unique_ptr<AddressesMap> Addresses,
             const std::vector<std::string> &Warnings,
-            UnloadCallbackTy UnloadFunc = nullptr)
-      : FileName(Name), Dwarf(std::move(Dwarf)),
-        Addresses(std::move(Addresses)), Warnings(Warnings),
-        UnloadFunc(UnloadFunc) {
-    if (this->Dwarf)
-      Endianess = this->Dwarf->isLittleEndian() ? support::endianness::little
-                                                : support::endianness::big;
-  }
+            UnloadCallbackTy UnloadFunc = nullptr);
 
   /// Object file name.
   StringRef FileName;
@@ -51,9 +44,6 @@ class DWARFFile {
   /// Warnings for object file.
   const std::vector<std::string> &Warnings;
 
-  /// Endiannes of source DWARF information.
-  support::endianness Endianess = support::endianness::little;
-
   /// Callback to the module keeping object file to unload.
   UnloadCallbackTy UnloadFunc;
 

diff  --git a/llvm/include/llvm/DWARFLinkerParallel/StringPool.h b/llvm/include/llvm/DWARFLinkerParallel/StringPool.h
index 44383ed6c7ddcc..8608476a8dc794 100644
--- a/llvm/include/llvm/DWARFLinkerParallel/StringPool.h
+++ b/llvm/include/llvm/DWARFLinkerParallel/StringPool.h
@@ -21,7 +21,7 @@ namespace dwarflinker_parallel {
 
 /// StringEntry keeps data of the string: the length, external offset
 /// and a string body which is placed right after StringEntry.
-using StringEntry = StringMapEntry<DwarfStringPoolEntry *>;
+using StringEntry = StringMapEntry<std::nullopt_t>;
 
 class StringPoolEntryInfo {
 public:
@@ -64,6 +64,8 @@ class StringPool
 
   parallel::PerThreadBumpPtrAllocator &getAllocatorRef() { return Allocator; }
 
+  void clear() { Allocator.Reset(); }
+
 private:
   parallel::PerThreadBumpPtrAllocator Allocator;
 };

diff  --git a/llvm/include/llvm/DWARFLinkerParallel/StringTable.h b/llvm/include/llvm/DWARFLinkerParallel/StringTable.h
deleted file mode 100644
index 4f8aece521d85d..00000000000000
--- a/llvm/include/llvm/DWARFLinkerParallel/StringTable.h
+++ /dev/null
@@ -1,88 +0,0 @@
-//===- StringTable.h --------------------------------------------*- C++ -*-===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_DWARFLINKERPARALLEL_STRINGTABLE_H
-#define LLVM_DWARFLINKERPARALLEL_STRINGTABLE_H
-
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/DWARFLinkerParallel/StringPool.h"
-
-namespace llvm {
-namespace dwarflinker_parallel {
-
-using StringsVector = SmallVector<StringEntry *>;
-
-/// This class prepares strings for emission into .debug_str table:
-/// translates string if necessary, assigns index and offset, keeps in order.
-class StringTable {
-public:
-  StringTable(StringPool &Strings,
-              std::function<StringRef(StringRef)> StringsTranslator)
-      : Strings(Strings), StringsTranslator(StringsTranslator) {}
-  ~StringTable() {}
-
-  /// Add string to the vector of strings which should be emitted.
-  /// Translate input string if neccessary, assign index and offset.
-  /// \returns updated string entry.
-  StringEntry *add(StringEntry *String) {
-    // Translate string if necessary.
-    if (StringsTranslator)
-      String = Strings.insert(StringsTranslator(String->first())).first;
-
-    // Store String for emission and assign index and offset.
-    if (String->getValue() == nullptr) {
-      DwarfStringPoolEntry *NewEntry =
-          Strings.getAllocatorRef().Allocate<DwarfStringPoolEntry>();
-
-      NewEntry->Symbol = nullptr;
-      NewEntry->Index = StringEntriesForEmission.size();
-
-      if (StringEntriesForEmission.empty())
-        NewEntry->Offset = 0;
-      else {
-        StringEntry *PrevString = StringEntriesForEmission.back();
-        NewEntry->Offset =
-            PrevString->getValue()->Offset + PrevString->getKeyLength() + 1;
-      }
-
-      String->getValue() = NewEntry;
-      StringEntriesForEmission.push_back(String);
-    }
-
-    return String;
-  }
-
-  /// Erase contents of StringsForEmission.
-  void clear() { StringEntriesForEmission.clear(); }
-
-  /// Enumerate all strings in sequential order and call \p Handler for each
-  /// string.
-  void forEach(function_ref<void(DwarfStringPoolEntryRef)> Handler) const {
-    for (const StringEntry *Entry : StringEntriesForEmission)
-      Handler(*Entry);
-  }
-
-  std::function<StringRef(StringRef)> getTranslator() {
-    return StringsTranslator;
-  }
-
-protected:
-  /// List of strings for emission.
-  StringsVector StringEntriesForEmission;
-
-  /// String pool for the translated strings.
-  StringPool &Strings;
-
-  /// Translator for the strings.
-  std::function<StringRef(StringRef)> StringsTranslator;
-};
-
-} // end of namespace dwarflinker_parallel
-} // end namespace llvm
-
-#endif // LLVM_DWARFLINKERPARALLEL_STRINGTABLE_H

diff  --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugMacro.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugMacro.h
index 10d4eb25a921b1..6b1b2ae6d7e049 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugMacro.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFDebugMacro.h
@@ -22,6 +22,7 @@ class DwarfStreamer;
 
 class DWARFDebugMacro {
   friend DwarfStreamer;
+  friend dwarflinker_parallel::CompileUnit;
 
   /// DWARFv5 section 6.3.1 Macro Information Header.
   enum HeaderFlagMask {

diff  --git a/llvm/lib/DWARFLinker/DWARFLinker.cpp b/llvm/lib/DWARFLinker/DWARFLinker.cpp
index 58c52534f05f45..3beb20b59baaaf 100644
--- a/llvm/lib/DWARFLinker/DWARFLinker.cpp
+++ b/llvm/lib/DWARFLinker/DWARFLinker.cpp
@@ -444,8 +444,10 @@ DWARFLinker::getVariableRelocAdjustment(AddressesMap &RelocMgr,
 
     const DWARFExpression::Operation &Op = *It;
     switch (Op.getCode()) {
+    case dwarf::DW_OP_const2u:
     case dwarf::DW_OP_const4u:
     case dwarf::DW_OP_const8u:
+    case dwarf::DW_OP_const2s:
     case dwarf::DW_OP_const4s:
     case dwarf::DW_OP_const8s:
       if (NextIt == Expression.end() || !isTlsAddressCode(NextIt->getCode()))

diff  --git a/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp b/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
index add0d94da73fc8..06559bc38c86cc 100644
--- a/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
+++ b/llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp
@@ -97,8 +97,10 @@ void CompileUnit::markEverythingAsKept() {
         ++NextIt;
 
         switch (It->getCode()) {
+        case dwarf::DW_OP_const2u:
         case dwarf::DW_OP_const4u:
         case dwarf::DW_OP_const8u:
+        case dwarf::DW_OP_const2s:
         case dwarf::DW_OP_const4s:
         case dwarf::DW_OP_const8s:
           if (NextIt == Expression.end() ||

diff  --git a/llvm/lib/DWARFLinkerParallel/ArrayList.h b/llvm/lib/DWARFLinkerParallel/ArrayList.h
new file mode 100644
index 00000000000000..67aea161f510e9
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/ArrayList.h
@@ -0,0 +1,92 @@
+//===- ArrayList.h ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_ARRAYLIST_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_ARRAYLIST_H
+
+#include "DWARFLinkerGlobalData.h"
+#include "llvm/Support/PerThreadBumpPtrAllocator.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+/// This class is a simple list of T structures. It keeps elements as
+/// pre-allocated groups to save memory for each element's next pointer.
+/// It allocates internal data using specified per-thread BumpPtrAllocator.
+template <typename T, size_t ItemsGroupSize = 512> class ArrayList {
+public:
+  /// Copy specified \p Item into the list.
+  T &noteItem(const T &Item) {
+    assert(Allocator != nullptr);
+
+    ItemsGroup *CurGroup = LastGroup;
+
+    if (CurGroup == nullptr) {
+      // Allocate first ItemsGroup.
+      LastGroup = Allocator->Allocate<ItemsGroup>();
+      LastGroup->ItemsCount = 0;
+      LastGroup->Next = nullptr;
+      GroupsHead = LastGroup;
+      CurGroup = LastGroup;
+    }
+
+    if (CurGroup->ItemsCount == ItemsGroupSize) {
+      // Allocate next ItemsGroup if current one is full.
+      LastGroup = Allocator->Allocate<ItemsGroup>();
+      LastGroup->ItemsCount = 0;
+      LastGroup->Next = nullptr;
+      CurGroup->Next = LastGroup;
+      CurGroup = LastGroup;
+    }
+
+    // Copy item into the next position inside current ItemsGroup.
+    CurGroup->Items[CurGroup->ItemsCount] = Item;
+    return CurGroup->Items[CurGroup->ItemsCount++];
+  }
+
+  using ItemHandlerTy = function_ref<void(T &)>;
+
+  /// Enumerate all items and apply specified \p Handler to each.
+  void forEach(ItemHandlerTy Handler) {
+    for (ItemsGroup *CurGroup = GroupsHead; CurGroup != nullptr;
+         CurGroup = CurGroup->Next) {
+      for (size_t Idx = 0; Idx < CurGroup->ItemsCount; Idx++) {
+        Handler(CurGroup->Items[Idx]);
+      }
+    }
+  }
+
+  /// Check whether list is empty.
+  bool empty() { return GroupsHead == nullptr; }
+
+  /// Erase list.
+  void erase() {
+    GroupsHead = nullptr;
+    LastGroup = nullptr;
+  }
+
+  void setAllocator(parallel::PerThreadBumpPtrAllocator *Allocator) {
+    this->Allocator = Allocator;
+  }
+
+protected:
+  struct ItemsGroup {
+    std::array<T, ItemsGroupSize> Items;
+    ItemsGroup *Next = nullptr;
+    size_t ItemsCount = 0;
+  };
+
+  ItemsGroup *GroupsHead = nullptr;
+  ItemsGroup *LastGroup = nullptr;
+  parallel::PerThreadBumpPtrAllocator *Allocator = nullptr;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_ARRAYLIST_H

diff  --git a/llvm/lib/DWARFLinkerParallel/CMakeLists.txt b/llvm/lib/DWARFLinkerParallel/CMakeLists.txt
index 8a1481c9df3e44..d321ecf8d5ce84 100644
--- a/llvm/lib/DWARFLinkerParallel/CMakeLists.txt
+++ b/llvm/lib/DWARFLinkerParallel/CMakeLists.txt
@@ -1,7 +1,12 @@
 add_llvm_component_library(LLVMDWARFLinkerParallel
+  DependencyTracker.cpp
+  DIEAttributeCloner.cpp
   DWARFEmitterImpl.cpp
+  DWARFFile.cpp
   DWARFLinker.cpp
+  DWARFLinkerCompileUnit.cpp
   DWARFLinkerImpl.cpp
+  DWARFLinkerUnit.cpp
   OutputSections.cpp
   StringPool.cpp
 

diff  --git a/llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.cpp b/llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.cpp
new file mode 100644
index 00000000000000..25a55026dd6755
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.cpp
@@ -0,0 +1,568 @@
+//=== DIEAttributeCloner.cpp ----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DIEAttributeCloner.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+void DIEAttributeCloner::clone() {
+  DWARFUnit &U = CU.getOrigUnit();
+
+  // Extract and clone every attribute.
+  DWARFDataExtractor Data = U.getDebugInfoExtractor();
+
+  uint64_t Offset = InputDieEntry->getOffset();
+  // Point to the next DIE (generally there is always at least a NULL
+  // entry after the current one). If this is a lone
+  // DW_TAG_compile_unit without any children, point to the next unit.
+  uint64_t NextOffset = (InputDIEIdx + 1 < U.getNumDIEs())
+                            ? U.getDIEAtIndex(InputDIEIdx + 1).getOffset()
+                            : U.getNextUnitOffset();
+
+  // We could copy the data only if we need to apply a relocation to it. After
+  // testing, it seems there is no performance downside to doing the copy
+  // unconditionally, and it makes the code simpler.
+  SmallString<40> DIECopy(Data.getData().substr(Offset, NextOffset - Offset));
+  Data =
+      DWARFDataExtractor(DIECopy, Data.isLittleEndian(), Data.getAddressSize());
+
+  // Modify the copy with relocated addresses.
+  CU.getContaingFile().Addresses->applyValidRelocs(DIECopy, Offset,
+                                                   Data.isLittleEndian());
+
+  // Reset the Offset to 0 as we will be working on the local copy of
+  // the data.
+  Offset = 0;
+
+  const auto *Abbrev = InputDieEntry->getAbbreviationDeclarationPtr();
+  Offset += getULEB128Size(Abbrev->getCode());
+
+  // Set current output offset.
+  AttrOutOffset = OutDIE->getOffset();
+  for (const auto &AttrSpec : Abbrev->attributes()) {
+    // Check whether current attribute should be skipped.
+    if (shouldSkipAttribute(AttrSpec)) {
+      DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
+                                U.getFormParams());
+      continue;
+    }
+
+    DWARFFormValue Val = AttrSpec.getFormValue();
+    Val.extractValue(Data, &Offset, U.getFormParams(), &U);
+
+    // Clone current attribute.
+    switch (AttrSpec.Form) {
+    case dwarf::DW_FORM_strp:
+    case dwarf::DW_FORM_line_strp:
+    case dwarf::DW_FORM_string:
+    case dwarf::DW_FORM_strx:
+    case dwarf::DW_FORM_strx1:
+    case dwarf::DW_FORM_strx2:
+    case dwarf::DW_FORM_strx3:
+    case dwarf::DW_FORM_strx4:
+      AttrOutOffset += cloneStringAttr(Val, AttrSpec);
+      break;
+    case dwarf::DW_FORM_ref_addr:
+    case dwarf::DW_FORM_ref1:
+    case dwarf::DW_FORM_ref2:
+    case dwarf::DW_FORM_ref4:
+    case dwarf::DW_FORM_ref8:
+    case dwarf::DW_FORM_ref_udata:
+      AttrOutOffset += cloneDieRefAttr(Val, AttrSpec);
+      break;
+    case dwarf::DW_FORM_data1:
+    case dwarf::DW_FORM_data2:
+    case dwarf::DW_FORM_data4:
+    case dwarf::DW_FORM_data8:
+    case dwarf::DW_FORM_udata:
+    case dwarf::DW_FORM_sdata:
+    case dwarf::DW_FORM_sec_offset:
+    case dwarf::DW_FORM_flag:
+    case dwarf::DW_FORM_flag_present:
+    case dwarf::DW_FORM_rnglistx:
+    case dwarf::DW_FORM_loclistx:
+    case dwarf::DW_FORM_implicit_const:
+      AttrOutOffset += cloneScalarAttr(Val, AttrSpec);
+      break;
+    case dwarf::DW_FORM_block:
+    case dwarf::DW_FORM_block1:
+    case dwarf::DW_FORM_block2:
+    case dwarf::DW_FORM_block4:
+    case dwarf::DW_FORM_exprloc:
+      AttrOutOffset += cloneBlockAttr(Val, AttrSpec);
+      break;
+    case dwarf::DW_FORM_addr:
+    case dwarf::DW_FORM_addrx:
+    case dwarf::DW_FORM_addrx1:
+    case dwarf::DW_FORM_addrx2:
+    case dwarf::DW_FORM_addrx3:
+    case dwarf::DW_FORM_addrx4:
+      AttrOutOffset += cloneAddressAttr(Val, AttrSpec);
+      break;
+    default:
+      CU.warn("unsupported attribute form " +
+                  dwarf::FormEncodingString(AttrSpec.Form) +
+                  " in DieAttributeCloner::clone(). Dropping.",
+              InputDieEntry);
+    }
+  }
+
+  // We convert source strings into the indexed form for DWARFv5.
+  // Check if original compile unit already has DW_AT_str_offsets_base
+  // attribute.
+  if (InputDieEntry->getTag() == dwarf::DW_TAG_compile_unit &&
+      CU.getVersion() >= 5 && !AttrInfo.HasStringOffsetBaseAttr) {
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugOffsetPatch{
+            AttrOutOffset,
+            &CU.getOrCreateSectionDescriptor(DebugSectionKind::DebugStrOffsets),
+            true},
+        PatchesOffsets);
+
+    AttrOutOffset += Generator
+                         .addScalarAttribute(dwarf::DW_AT_str_offsets_base,
+                                             dwarf::DW_FORM_sec_offset,
+                                             CU.getDebugStrOffsetsHeaderSize())
+                         .second;
+  }
+}
+
+bool DIEAttributeCloner::shouldSkipAttribute(
+    DWARFAbbreviationDeclaration::AttributeSpec AttrSpec) {
+  switch (AttrSpec.Attr) {
+  default:
+    return false;
+  case dwarf::DW_AT_low_pc:
+  case dwarf::DW_AT_high_pc:
+  case dwarf::DW_AT_ranges:
+    if (CU.getGlobalData().getOptions().UpdateIndexTablesOnly)
+      return false;
+
+    // Skip address attribute if we are in function scope and function does not
+    // reference live address.
+    return CU.getDIEInfo(InputDIEIdx).getIsInFunctionScope() &&
+           !FuncAddressAdjustment.has_value();
+  case dwarf::DW_AT_rnglists_base:
+    // In case !Update the .debug_addr table is not generated/preserved.
+    // Thus instead of DW_FORM_rnglistx the DW_FORM_sec_offset is used.
+    // Since DW_AT_rnglists_base is used for only DW_FORM_rnglistx the
+    // DW_AT_rnglists_base is removed.
+    return !CU.getGlobalData().getOptions().UpdateIndexTablesOnly;
+  case dwarf::DW_AT_loclists_base:
+    // In case !Update the .debug_addr table is not generated/preserved.
+    // Thus instead of DW_FORM_loclistx the DW_FORM_sec_offset is used.
+    // Since DW_AT_loclists_base is used for only DW_FORM_loclistx the
+    // DW_AT_loclists_base is removed.
+    return !CU.getGlobalData().getOptions().UpdateIndexTablesOnly;
+  case dwarf::DW_AT_location:
+  case dwarf::DW_AT_frame_base:
+    if (CU.getGlobalData().getOptions().UpdateIndexTablesOnly)
+      return false;
+
+    // When location expression contains an address: skip this attribute
+    // if it does not reference live address.
+    if (HasLocationExpressionAddress)
+      return !VarAddressAdjustment.has_value();
+
+    // Skip location attribute if we are in function scope and function does not
+    // reference live address.
+    return CU.getDIEInfo(InputDIEIdx).getIsInFunctionScope() &&
+           !FuncAddressAdjustment.has_value();
+  }
+}
+
+size_t DIEAttributeCloner::cloneStringAttr(
+    const DWARFFormValue &Val,
+    const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec) {
+  std::optional<const char *> String = dwarf::toString(Val);
+  if (!String) {
+    CU.warn("cann't read string attribute.");
+    return 0;
+  }
+
+  StringEntry *StringInPool =
+      CU.getGlobalData().getStringPool().insert(*String).first;
+  if (AttrSpec.Form == dwarf::DW_FORM_line_strp) {
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugLineStrPatch{{AttrOutOffset}, StringInPool}, PatchesOffsets);
+    return Generator
+        .addStringPlaceholderAttribute(AttrSpec.Attr, dwarf::DW_FORM_line_strp)
+        .second;
+  }
+
+  // Update attributes info.
+  if (AttrSpec.Attr == dwarf::DW_AT_name)
+    AttrInfo.Name = StringInPool;
+  else if (AttrSpec.Attr == dwarf::DW_AT_MIPS_linkage_name ||
+           AttrSpec.Attr == dwarf::DW_AT_linkage_name)
+    AttrInfo.MangledName = StringInPool;
+
+  if (CU.getVersion() < 5) {
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugStrPatch{{AttrOutOffset}, StringInPool}, PatchesOffsets);
+
+    return Generator
+        .addStringPlaceholderAttribute(AttrSpec.Attr, dwarf::DW_FORM_strp)
+        .second;
+  }
+
+  return Generator
+      .addIndexedStringAttribute(AttrSpec.Attr, dwarf::DW_FORM_strx,
+                                 CU.getDebugStrIndex(StringInPool))
+      .second;
+}
+
+size_t DIEAttributeCloner::cloneDieRefAttr(
+    const DWARFFormValue &Val,
+    const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec) {
+  if (AttrSpec.Attr == dwarf::DW_AT_sibling)
+    return 0;
+
+  std::optional<std::pair<CompileUnit *, uint32_t>> RefDiePair =
+      CU.resolveDIEReference(Val);
+  if (!RefDiePair) {
+    // If the referenced DIE is not found,  drop the attribute.
+    CU.warn("cann't find referenced DIE.", InputDieEntry);
+    return 0;
+  }
+  assert(RefDiePair->first->getStage() >= CompileUnit::Stage::Loaded);
+  assert(RefDiePair->second != 0);
+
+  // Get output offset for referenced DIE.
+  uint64_t OutDieOffset =
+      RefDiePair->first->getDieOutOffset(RefDiePair->second);
+
+  // Examine whether referenced DIE is in current compile unit.
+  bool IsLocal = CU.getUniqueID() == RefDiePair->first->getUniqueID();
+
+  // Set attribute form basing on the kind of referenced DIE(local or not?).
+  dwarf::Form NewForm = IsLocal ? dwarf::DW_FORM_ref4 : dwarf::DW_FORM_ref_addr;
+
+  // Check whether current attribute references already cloned DIE inside
+  // the same compilation unit. If true - write the already known offset value.
+  if (IsLocal && (OutDieOffset != 0))
+    return Generator.addScalarAttribute(AttrSpec.Attr, NewForm, OutDieOffset)
+        .second;
+
+  // If offset value is not known at this point then create patch for the
+  // reference value and write dummy value into the attribute.
+  DebugInfoOutputSection.notePatchWithOffsetUpdate(
+      DebugDieRefPatch{AttrOutOffset, &CU, RefDiePair->first,
+                       RefDiePair->second},
+      PatchesOffsets);
+  return Generator.addScalarAttribute(AttrSpec.Attr, NewForm, 0xBADDEF).second;
+}
+
+size_t DIEAttributeCloner::cloneScalarAttr(
+    const DWARFFormValue &Val,
+    const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec) {
+
+  // Create patches for attribute referencing other non invariant section.
+  // Invariant section could not be updated here as this section and
+  // reference to it do not change value in case --update.
+  if (AttrSpec.Attr == dwarf::DW_AT_macro_info) {
+    if (std::optional<uint64_t> Offset = Val.getAsSectionOffset()) {
+      const DWARFDebugMacro *Macro =
+          CU.getContaingFile().Dwarf->getDebugMacinfo();
+      if (Macro == nullptr || !Macro->hasEntryForOffset(*Offset))
+        return 0;
+
+      DebugInfoOutputSection.notePatchWithOffsetUpdate(
+          DebugOffsetPatch{AttrOutOffset, &CU.getOrCreateSectionDescriptor(
+                                              DebugSectionKind::DebugMacinfo)},
+          PatchesOffsets);
+    }
+  } else if (AttrSpec.Attr == dwarf::DW_AT_macros) {
+    if (std::optional<uint64_t> Offset = Val.getAsSectionOffset()) {
+      const DWARFDebugMacro *Macro =
+          CU.getContaingFile().Dwarf->getDebugMacro();
+      if (Macro == nullptr || !Macro->hasEntryForOffset(*Offset))
+        return 0;
+
+      DebugInfoOutputSection.notePatchWithOffsetUpdate(
+          DebugOffsetPatch{AttrOutOffset, &CU.getOrCreateSectionDescriptor(
+                                              DebugSectionKind::DebugMacro)},
+          PatchesOffsets);
+    }
+  } else if (AttrSpec.Attr == dwarf::DW_AT_stmt_list) {
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugOffsetPatch{AttrOutOffset, &CU.getOrCreateSectionDescriptor(
+                                            DebugSectionKind::DebugLine)},
+        PatchesOffsets);
+  } else if (AttrSpec.Attr == dwarf::DW_AT_str_offsets_base) {
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugOffsetPatch{
+            AttrOutOffset,
+            &CU.getOrCreateSectionDescriptor(DebugSectionKind::DebugStrOffsets),
+            true},
+        PatchesOffsets);
+
+    // Use size of .debug_str_offsets header as attribute value. The offset
+    // to .debug_str_offsets would be added later while patching.
+    AttrInfo.HasStringOffsetBaseAttr = true;
+    return Generator
+        .addScalarAttribute(AttrSpec.Attr, AttrSpec.Form,
+                            CU.getDebugStrOffsetsHeaderSize())
+        .second;
+  }
+
+  uint64_t Value;
+  if (CU.getGlobalData().getOptions().UpdateIndexTablesOnly) {
+    if (auto OptionalValue = Val.getAsUnsignedConstant())
+      Value = *OptionalValue;
+    else if (auto OptionalValue = Val.getAsSignedConstant())
+      Value = *OptionalValue;
+    else if (auto OptionalValue = Val.getAsSectionOffset())
+      Value = *OptionalValue;
+    else {
+      CU.warn("unsupported scalar attribute form. Dropping attribute.",
+              InputDieEntry);
+      return 0;
+    }
+
+    if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value)
+      AttrInfo.IsDeclaration = true;
+
+    if (AttrSpec.Form == dwarf::DW_FORM_loclistx)
+      return Generator.addLocListAttribute(AttrSpec.Attr, AttrSpec.Form, Value)
+          .second;
+
+    return Generator.addScalarAttribute(AttrSpec.Attr, AttrSpec.Form, Value)
+        .second;
+  }
+
+  dwarf::Form ResultingForm = AttrSpec.Form;
+  if (AttrSpec.Form == dwarf::DW_FORM_rnglistx) {
+    // DWARFLinker does not generate .debug_addr table. Thus we need to change
+    // all "addrx" related forms to "addr" version. Change DW_FORM_rnglistx
+    // to DW_FORM_sec_offset here.
+    std::optional<uint64_t> Index = Val.getAsSectionOffset();
+    if (!Index) {
+      CU.warn("cann't read the attribute. Dropping.", InputDieEntry);
+      return 0;
+    }
+    std::optional<uint64_t> Offset = CU.getOrigUnit().getRnglistOffset(*Index);
+    if (!Offset) {
+      CU.warn("cann't read the attribute. Dropping.", InputDieEntry);
+      return 0;
+    }
+
+    Value = *Offset;
+    ResultingForm = dwarf::DW_FORM_sec_offset;
+  } else if (AttrSpec.Form == dwarf::DW_FORM_loclistx) {
+    // DWARFLinker does not generate .debug_addr table. Thus we need to change
+    // all "addrx" related forms to "addr" version. Change DW_FORM_loclistx
+    // to DW_FORM_sec_offset here.
+    std::optional<uint64_t> Index = Val.getAsSectionOffset();
+    if (!Index) {
+      CU.warn("cann't read the attribute. Dropping.", InputDieEntry);
+      return 0;
+    }
+    std::optional<uint64_t> Offset = CU.getOrigUnit().getLoclistOffset(*Index);
+    if (!Offset) {
+      CU.warn("cann't read the attribute. Dropping.", InputDieEntry);
+      return 0;
+    }
+
+    Value = *Offset;
+    ResultingForm = dwarf::DW_FORM_sec_offset;
+  } else if (AttrSpec.Attr == dwarf::DW_AT_high_pc &&
+             InputDieEntry->getTag() == dwarf::DW_TAG_compile_unit) {
+    std::optional<uint64_t> LowPC = CU.getLowPc();
+    if (!LowPC)
+      return 0;
+    // Dwarf >= 4 high_pc is an size, not an address.
+    Value = CU.getHighPc() - *LowPC;
+  } else if (AttrSpec.Form == dwarf::DW_FORM_sec_offset)
+    Value = *Val.getAsSectionOffset();
+  else if (AttrSpec.Form == dwarf::DW_FORM_sdata)
+    Value = *Val.getAsSignedConstant();
+  else if (auto OptionalValue = Val.getAsUnsignedConstant())
+    Value = *OptionalValue;
+  else {
+    CU.warn("unsupported scalar attribute form. Dropping attribute.",
+            InputDieEntry);
+    return 0;
+  }
+
+  if (AttrSpec.Attr == dwarf::DW_AT_ranges ||
+      AttrSpec.Attr == dwarf::DW_AT_start_scope) {
+    // Create patch for the range offset value.
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugRangePatch{{AttrOutOffset},
+                        InputDieEntry->getTag() == dwarf::DW_TAG_compile_unit},
+        PatchesOffsets);
+    AttrInfo.HasRanges = true;
+  } else if (DWARFAttribute::mayHaveLocationList(AttrSpec.Attr) &&
+             dwarf::doesFormBelongToClass(AttrSpec.Form,
+                                          DWARFFormValue::FC_SectionOffset,
+                                          CU.getOrigUnit().getVersion())) {
+    int64_t AddrAdjustmentValue = 0;
+    if (VarAddressAdjustment)
+      AddrAdjustmentValue = *VarAddressAdjustment;
+    else if (FuncAddressAdjustment)
+      AddrAdjustmentValue = *FuncAddressAdjustment;
+
+    // Create patch for the location offset value.
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugLocPatch{{AttrOutOffset}, AddrAdjustmentValue}, PatchesOffsets);
+  } else if (AttrSpec.Attr == dwarf::DW_AT_addr_base) {
+    DebugInfoOutputSection.notePatchWithOffsetUpdate(
+        DebugOffsetPatch{
+            AttrOutOffset,
+            &CU.getOrCreateSectionDescriptor(DebugSectionKind::DebugAddr),
+            true},
+        PatchesOffsets);
+
+    // Use size of .debug_addr header as attribute value. The offset to
+    // .debug_addr would be added later while patching.
+    return Generator
+        .addScalarAttribute(AttrSpec.Attr, AttrSpec.Form,
+                            CU.getDebugAddrHeaderSize())
+        .second;
+  } else if (AttrSpec.Attr == dwarf::DW_AT_declaration && Value)
+    AttrInfo.IsDeclaration = true;
+
+  return Generator.addScalarAttribute(AttrSpec.Attr, ResultingForm, Value)
+      .second;
+}
+
+size_t DIEAttributeCloner::cloneBlockAttr(
+    const DWARFFormValue &Val,
+    const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec) {
+
+  size_t NumberOfPatchesAtStart = PatchesOffsets.size();
+
+  // If the block is a DWARF Expression, clone it into the temporary
+  // buffer using cloneExpression(), otherwise copy the data directly.
+  SmallVector<uint8_t, 32> Buffer;
+  ArrayRef<uint8_t> Bytes = *Val.getAsBlock();
+  if (DWARFAttribute::mayHaveLocationExpr(AttrSpec.Attr) &&
+      (Val.isFormClass(DWARFFormValue::FC_Block) ||
+       Val.isFormClass(DWARFFormValue::FC_Exprloc))) {
+    DWARFUnit &OrigUnit = CU.getOrigUnit();
+    DataExtractor Data(StringRef((const char *)Bytes.data(), Bytes.size()),
+                       OrigUnit.isLittleEndian(),
+                       OrigUnit.getAddressByteSize());
+    DWARFExpression Expr(Data, OrigUnit.getAddressByteSize(),
+                         OrigUnit.getFormParams().Format);
+
+    CU.cloneDieAttrExpression(Expr, Buffer, DebugInfoOutputSection,
+                              VarAddressAdjustment, PatchesOffsets);
+    Bytes = Buffer;
+  }
+
+  // The expression location data might be updated and exceed the original size.
+  // Check whether the new data fits into the original form.
+  dwarf::Form ResultForm = AttrSpec.Form;
+  if ((ResultForm == dwarf::DW_FORM_block1 && Bytes.size() > UINT8_MAX) ||
+      (ResultForm == dwarf::DW_FORM_block2 && Bytes.size() > UINT16_MAX) ||
+      (ResultForm == dwarf::DW_FORM_block4 && Bytes.size() > UINT32_MAX))
+    ResultForm = dwarf::DW_FORM_block;
+
+  size_t FinalAttributeSize;
+  if (AttrSpec.Form == dwarf::DW_FORM_exprloc)
+    FinalAttributeSize =
+        Generator.addLocationAttribute(AttrSpec.Attr, ResultForm, Bytes).second;
+  else
+    FinalAttributeSize =
+        Generator.addBlockAttribute(AttrSpec.Attr, ResultForm, Bytes).second;
+
+  // Update patches offsets with the size of length field for Bytes.
+  for (size_t Idx = NumberOfPatchesAtStart; Idx < PatchesOffsets.size();
+       Idx++) {
+    assert(FinalAttributeSize > Bytes.size());
+    *PatchesOffsets[Idx] +=
+        (AttrOutOffset + (FinalAttributeSize - Bytes.size()));
+  }
+
+  return FinalAttributeSize;
+}
+
+size_t DIEAttributeCloner::cloneAddressAttr(
+    const DWARFFormValue &Val,
+    const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec) {
+  if (AttrSpec.Attr == dwarf::DW_AT_low_pc)
+    AttrInfo.HasLowPc = true;
+
+  if (CU.getGlobalData().getOptions().UpdateIndexTablesOnly)
+    return Generator
+        .addScalarAttribute(AttrSpec.Attr, AttrSpec.Form, Val.getRawUValue())
+        .second;
+
+  // Cloned Die may have address attributes relocated to a
+  // totally unrelated value. This can happen:
+  //   - If high_pc is an address (Dwarf version == 2), then it might have been
+  //     relocated to a totally unrelated value (because the end address in the
+  //     object file might be start address of another function which got moved
+  //     independently by the linker).
+  //   - If address relocated in an inline_subprogram that happens at the
+  //     beginning of its inlining function.
+  //  To avoid above cases and to not apply relocation twice (in
+  //  applyValidRelocs and here), read address attribute from InputDIE and apply
+  //  Info.PCOffset here.
+
+  std::optional<DWARFFormValue> AddrAttribute =
+      CU.find(InputDieEntry, AttrSpec.Attr);
+  if (!AddrAttribute)
+    llvm_unreachable("Cann't find attribute");
+
+  std::optional<uint64_t> Addr = AddrAttribute->getAsAddress();
+  if (!Addr) {
+    CU.warn("cann't read address attribute value.");
+    return 0;
+  }
+
+  if (InputDieEntry->getTag() == dwarf::DW_TAG_compile_unit &&
+      AttrSpec.Attr == dwarf::DW_AT_low_pc) {
+    if (std::optional<uint64_t> LowPC = CU.getLowPc())
+      Addr = *LowPC;
+    else
+      return 0;
+  } else if (InputDieEntry->getTag() == dwarf::DW_TAG_compile_unit &&
+             AttrSpec.Attr == dwarf::DW_AT_high_pc) {
+    if (uint64_t HighPc = CU.getHighPc())
+      Addr = HighPc;
+    else
+      return 0;
+  } else {
+    if (VarAddressAdjustment)
+      *Addr += *VarAddressAdjustment;
+    else if (FuncAddressAdjustment)
+      *Addr += *FuncAddressAdjustment;
+  }
+
+  if (AttrSpec.Form == dwarf::DW_FORM_addr) {
+    return Generator.addScalarAttribute(AttrSpec.Attr, AttrSpec.Form, *Addr)
+        .second;
+  }
+
+  return Generator
+      .addScalarAttribute(AttrSpec.Attr, dwarf::Form::DW_FORM_addrx,
+                          CU.getDebugAddrIndex(*Addr))
+      .second;
+}
+
+unsigned DIEAttributeCloner::finalizeAbbreviations(bool HasChildrenToClone) {
+  size_t SizeOfAbbreviationNumber =
+      Generator.finalizeAbbreviations(HasChildrenToClone);
+
+  // We need to update patches offsets after we know the size of the
+  // abbreviation number.
+  updatePatchesWithSizeOfAbbreviationNumber(SizeOfAbbreviationNumber);
+
+  // Add the size of the abbreviation number to the output offset.
+  AttrOutOffset += SizeOfAbbreviationNumber;
+
+  return AttrOutOffset;
+}
+
+} // end of namespace dwarflinker_parallel
+} // namespace llvm

diff  --git a/llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.h b/llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.h
new file mode 100644
index 00000000000000..d590b1805e8efd
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DIEAttributeCloner.h
@@ -0,0 +1,147 @@
+//===- DIEAttributeCloner.h -------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_DIEATTRIBUTECLONER_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_DIEATTRIBUTECLONER_H
+
+#include "ArrayList.h"
+#include "DIEGenerator.h"
+#include "DWARFLinkerCompileUnit.h"
+#include "DWARFLinkerGlobalData.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+/// This class creates clones of input DIE attributes.
+/// It enumerates attributes of input DIE, creates clone for each
+/// attribute, adds cloned attribute to the output DIE.
+class DIEAttributeCloner {
+public:
+  DIEAttributeCloner(DIE *OutDIE, CompileUnit &CU,
+                     const DWARFDebugInfoEntry *InputDieEntry,
+                     DIEGenerator &Generator,
+                     std::optional<int64_t> FuncAddressAdjustment,
+                     std::optional<int64_t> VarAddressAdjustment,
+                     bool HasLocationExpressionAddress)
+      : OutDIE(OutDIE), CU(CU),
+        DebugInfoOutputSection(
+            CU.getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo)),
+        InputDieEntry(InputDieEntry), Generator(Generator),
+        FuncAddressAdjustment(FuncAddressAdjustment),
+        VarAddressAdjustment(VarAddressAdjustment),
+        HasLocationExpressionAddress(HasLocationExpressionAddress) {
+    InputDIEIdx = CU.getDIEIndex(InputDieEntry);
+  }
+
+  /// Clone attributes of input DIE.
+  void clone();
+
+  /// Create abbreviations for the output DIE after all attributes are cloned.
+  unsigned finalizeAbbreviations(bool HasChildrenToClone);
+
+  /// Information gathered and exchanged between the various
+  /// clone*Attr helpers about the attributes of a particular DIE.
+  ///
+  /// Cannot be used concurrently.
+  struct AttributesInfo {
+    /// Names.
+    StringEntry *Name = nullptr;
+    StringEntry *MangledName = nullptr;
+    StringEntry *NameWithoutTemplate = nullptr;
+
+    /// Does the DIE have a low_pc attribute?
+    bool HasLowPc = false;
+
+    /// Is this DIE only a declaration?
+    bool IsDeclaration = false;
+
+    /// Does the DIE have a ranges attribute?
+    bool HasRanges = false;
+
+    /// Does the DIE have a string offset attribute?
+    bool HasStringOffsetBaseAttr = false;
+  };
+
+  AttributesInfo AttrInfo;
+
+protected:
+  /// Clone string attribute.
+  size_t
+  cloneStringAttr(const DWARFFormValue &Val,
+                  const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec);
+
+  /// Clone attribute referencing another DIE.
+  size_t
+  cloneDieRefAttr(const DWARFFormValue &Val,
+                  const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec);
+
+  /// Clone scalar attribute.
+  size_t
+  cloneScalarAttr(const DWARFFormValue &Val,
+                  const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec);
+
+  /// Clone block or exprloc attribute.
+  size_t
+  cloneBlockAttr(const DWARFFormValue &Val,
+                 const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec);
+
+  /// Clone address attribute.
+  size_t
+  cloneAddressAttr(const DWARFFormValue &Val,
+                   const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec);
+
+  /// Returns true if attribute should be skipped.
+  bool
+  shouldSkipAttribute(DWARFAbbreviationDeclaration::AttributeSpec AttrSpec);
+
+  /// Update patches offsets with the size of abbreviation number.
+  void
+  updatePatchesWithSizeOfAbbreviationNumber(unsigned SizeOfAbbreviationNumber) {
+    for (uint64_t *OffsetPtr : PatchesOffsets)
+      *OffsetPtr += SizeOfAbbreviationNumber;
+  }
+
+  /// Output DIE.
+  DIE *OutDIE = nullptr;
+
+  /// Compile unit for the output DIE.
+  CompileUnit &CU;
+
+  /// .debug_info section descriptor.
+  SectionDescriptor &DebugInfoOutputSection;
+
+  /// Input DIE entry.
+  const DWARFDebugInfoEntry *InputDieEntry = nullptr;
+
+  /// Input DIE index.
+  uint32_t InputDIEIdx = 0;
+
+  /// Output DIE generator.
+  DIEGenerator &Generator;
+
+  /// Relocation adjustment for the function address ranges.
+  std::optional<int64_t> FuncAddressAdjustment;
+
+  /// Relocation adjustment for the variable locations.
+  std::optional<int64_t> VarAddressAdjustment;
+
+  /// Indicates whether InputDieEntry has an location attribute
+  /// containg address expression.
+  bool HasLocationExpressionAddress = false;
+
+  /// Output offset after all attributes.
+  unsigned AttrOutOffset = 0;
+
+  /// Patches for the cloned attributes.
+  OffsetsPtrVector PatchesOffsets;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_DIEATTRIBUTECLONER_H

diff  --git a/llvm/lib/DWARFLinkerParallel/DIEGenerator.h b/llvm/lib/DWARFLinkerParallel/DIEGenerator.h
new file mode 100644
index 00000000000000..c0bbce0f520143
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DIEGenerator.h
@@ -0,0 +1,165 @@
+//===- DIEGenerator.h -------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_DIEGENERATOR_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_DIEGENERATOR_H
+
+#include "DWARFLinkerGlobalData.h"
+#include "DWARFLinkerUnit.h"
+#include "llvm/CodeGen/DIE.h"
+#include "llvm/Support/LEB128.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+/// This class is a helper to create output DIE tree.
+class DIEGenerator {
+public:
+  DIEGenerator(BumpPtrAllocator &Allocator, DwarfUnit &CU)
+      : Allocator(Allocator), CU(CU) {}
+
+  /// Creates a DIE of specified tag \p DieTag and \p OutOffset.
+  DIE *createDIE(dwarf::Tag DieTag, uint32_t OutOffset) {
+    OutputDIE = DIE::get(Allocator, DieTag);
+
+    OutputDIE->setOffset(OutOffset);
+
+    return OutputDIE;
+  }
+
+  /// Adds a specified \p Child to the current DIE.
+  void addChild(DIE *Child) {
+    assert(Child != nullptr);
+    assert(OutputDIE != nullptr);
+
+    OutputDIE->addChild(Child);
+  }
+
+  /// Adds specified scalar attribute to the current DIE.
+  std::pair<DIEValue &, size_t> addScalarAttribute(dwarf::Attribute Attr,
+                                                   dwarf::Form AttrForm,
+                                                   uint64_t Value) {
+    return addAttribute(Attr, AttrForm, DIEInteger(Value));
+  }
+
+  /// Adds specified location attribute to the current DIE.
+  std::pair<DIEValue &, size_t> addLocationAttribute(dwarf::Attribute Attr,
+                                                     dwarf::Form AttrForm,
+                                                     ArrayRef<uint8_t> Bytes) {
+    DIELoc *Loc = new (Allocator) DIELoc;
+    for (auto Byte : Bytes)
+      static_cast<DIEValueList *>(Loc)->addValue(
+          Allocator, static_cast<dwarf::Attribute>(0), dwarf::DW_FORM_data1,
+          DIEInteger(Byte));
+    Loc->setSize(Bytes.size());
+
+    return addAttribute(Attr, AttrForm, Loc);
+  }
+
+  /// Adds specified block or exprloc attribute to the current DIE.
+  std::pair<DIEValue &, size_t> addBlockAttribute(dwarf::Attribute Attr,
+                                                  dwarf::Form AttrForm,
+                                                  ArrayRef<uint8_t> Bytes) {
+    // The expression location data might be updated and exceed the original
+    // size. Check whether the new data fits into the original form.
+    assert((AttrForm == dwarf::DW_FORM_block) ||
+           (AttrForm == dwarf::DW_FORM_exprloc) ||
+           (AttrForm == dwarf::DW_FORM_block1 && Bytes.size() <= UINT8_MAX) ||
+           (AttrForm == dwarf::DW_FORM_block2 && Bytes.size() <= UINT16_MAX) ||
+           (AttrForm == dwarf::DW_FORM_block4 && Bytes.size() <= UINT32_MAX));
+
+    DIEBlock *Block = new (Allocator) DIEBlock;
+    for (auto Byte : Bytes)
+      static_cast<DIEValueList *>(Block)->addValue(
+          Allocator, static_cast<dwarf::Attribute>(0), dwarf::DW_FORM_data1,
+          DIEInteger(Byte));
+    Block->setSize(Bytes.size());
+
+    return addAttribute(Attr, AttrForm, Block);
+  }
+
+  /// Adds specified location list attribute to the current DIE.
+  std::pair<DIEValue &, size_t> addLocListAttribute(dwarf::Attribute Attr,
+                                                    dwarf::Form AttrForm,
+                                                    uint64_t Value) {
+    return addAttribute(Attr, AttrForm, DIELocList(Value));
+  }
+
+  /// Adds indexed string attribute.
+  std::pair<DIEValue &, size_t> addIndexedStringAttribute(dwarf::Attribute Attr,
+                                                          dwarf::Form AttrForm,
+                                                          uint64_t Idx) {
+    assert(AttrForm == dwarf::DW_FORM_strx);
+    return addAttribute(Attr, AttrForm, DIEInteger(Idx));
+  }
+
+  /// Adds string attribute with dummy offset to the current DIE.
+  std::pair<DIEValue &, size_t>
+  addStringPlaceholderAttribute(dwarf::Attribute Attr, dwarf::Form AttrForm) {
+    assert(AttrForm == dwarf::DW_FORM_strp ||
+           AttrForm == dwarf::DW_FORM_line_strp);
+    return addAttribute(Attr, AttrForm, DIEInteger(0xBADDEF));
+  }
+
+  /// Adds inplace string attribute to the current DIE.
+  std::pair<DIEValue &, size_t> addInplaceString(dwarf::Attribute Attr,
+                                                 StringRef String) {
+    DIEBlock *Block = new (Allocator) DIEBlock;
+    for (auto Byte : String.bytes())
+      static_cast<DIEValueList *>(Block)->addValue(
+          Allocator, static_cast<dwarf::Attribute>(0), dwarf::DW_FORM_data1,
+          DIEInteger(Byte));
+
+    static_cast<DIEValueList *>(Block)->addValue(
+        Allocator, static_cast<dwarf::Attribute>(0), dwarf::DW_FORM_data1,
+        DIEInteger(0));
+    Block->setSize(String.size() + 1);
+
+    DIEValue &ValueRef =
+        *OutputDIE->addValue(Allocator, Attr, dwarf::DW_FORM_string, Block);
+    return std::pair<DIEValue &, size_t>(ValueRef, String.size() + 1);
+  }
+
+  /// Creates appreviations for the current DIE. Returns value of
+  /// abbreviation number.
+  size_t finalizeAbbreviations(bool CHILDREN_yes) {
+    // Create abbreviations for output DIE.
+    DIEAbbrev NewAbbrev = OutputDIE->generateAbbrev();
+    if (CHILDREN_yes)
+      NewAbbrev.setChildrenFlag(dwarf::DW_CHILDREN_yes);
+
+    CU.assignAbbrev(NewAbbrev);
+    OutputDIE->setAbbrevNumber(NewAbbrev.getNumber());
+
+    return getULEB128Size(OutputDIE->getAbbrevNumber());
+  }
+
+protected:
+  template <typename T>
+  std::pair<DIEValue &, size_t> addAttribute(dwarf::Attribute Attr,
+                                             dwarf::Form AttrForm, T &&Value) {
+    DIEValue &ValueRef =
+        *OutputDIE->addValue(Allocator, Attr, AttrForm, std::forward<T>(Value));
+    unsigned ValueSize = ValueRef.sizeOf(CU.getFormParams());
+    return std::pair<DIEValue &, size_t>(ValueRef, ValueSize);
+  }
+
+  // Allocator for output DIEs and values.
+  BumpPtrAllocator &Allocator;
+
+  // Unit for the output DIE.
+  DwarfUnit &CU;
+
+  // OutputDIE.
+  DIE *OutputDIE = nullptr;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_DIEGENERATOR_H

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.cpp b/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.cpp
index 50909c0ba66937..38898ac6f2fa2f 100644
--- a/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.cpp
+++ b/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.cpp
@@ -114,18 +114,115 @@ Error DwarfEmitterImpl::init(Triple TheTriple,
                              TripleName.c_str());
   Asm->setDwarfUsesRelocationsAcrossSections(false);
 
-  RangesSectionSize = 0;
-  RngListsSectionSize = 0;
-  LocSectionSize = 0;
-  LocListsSectionSize = 0;
-  LineSectionSize = 0;
-  FrameSectionSize = 0;
   DebugInfoSectionSize = 0;
-  MacInfoSectionSize = 0;
-  MacroSectionSize = 0;
 
   return Error::success();
 }
 
+void DwarfEmitterImpl::emitSwiftAST(StringRef Buffer) {
+  MCSection *SwiftASTSection = MOFI->getDwarfSwiftASTSection();
+  SwiftASTSection->setAlignment(Align(32));
+  MS->switchSection(SwiftASTSection);
+  MS->emitBytes(Buffer);
+}
+
+/// Emit the swift reflection section stored in \p Buffer.
+void DwarfEmitterImpl::emitSwiftReflectionSection(
+    llvm::binaryformat::Swift5ReflectionSectionKind ReflSectionKind,
+    StringRef Buffer, uint32_t Alignment, uint32_t) {
+  MCSection *ReflectionSection =
+      MOFI->getSwift5ReflectionSection(ReflSectionKind);
+  if (ReflectionSection == nullptr)
+    return;
+  ReflectionSection->setAlignment(Align(Alignment));
+  MS->switchSection(ReflectionSection);
+  MS->emitBytes(Buffer);
+}
+
+void DwarfEmitterImpl::emitSectionContents(StringRef SecData,
+                                           StringRef SecName) {
+  if (SecData.empty())
+    return;
+
+  if (MCSection *Section = switchSection(SecName)) {
+    MS->switchSection(Section);
+
+    MS->emitBytes(SecData);
+  }
+}
+
+MCSection *DwarfEmitterImpl::switchSection(StringRef SecName) {
+  return StringSwitch<MCSection *>(SecName)
+      .Case("debug_info", MC->getObjectFileInfo()->getDwarfInfoSection())
+      .Case("debug_abbrev", MC->getObjectFileInfo()->getDwarfAbbrevSection())
+      .Case("debug_line", MC->getObjectFileInfo()->getDwarfLineSection())
+      .Case("debug_loc", MC->getObjectFileInfo()->getDwarfLocSection())
+      .Case("debug_ranges", MC->getObjectFileInfo()->getDwarfRangesSection())
+      .Case("debug_frame", MC->getObjectFileInfo()->getDwarfFrameSection())
+      .Case("debug_aranges", MC->getObjectFileInfo()->getDwarfARangesSection())
+      .Case("debug_rnglists",
+            MC->getObjectFileInfo()->getDwarfRnglistsSection())
+      .Case("debug_loclists",
+            MC->getObjectFileInfo()->getDwarfLoclistsSection())
+      .Case("debug_macro", MC->getObjectFileInfo()->getDwarfMacroSection())
+      .Case("debug_macinfo", MC->getObjectFileInfo()->getDwarfMacinfoSection())
+      .Case("debug_addr", MC->getObjectFileInfo()->getDwarfAddrSection())
+      .Case("debug_str", MC->getObjectFileInfo()->getDwarfStrSection())
+      .Case("debug_line_str", MC->getObjectFileInfo()->getDwarfLineStrSection())
+      .Case("debug_str_offsets",
+            MC->getObjectFileInfo()->getDwarfStrOffSection())
+      .Default(nullptr);
+}
+
+MCSymbol *DwarfEmitterImpl::emitTempSym(StringRef SecName, StringRef SymName) {
+  if (MCSection *Section = switchSection(SecName)) {
+    MS->switchSection(Section);
+    MCSymbol *Res = Asm->createTempSymbol(SymName);
+    Asm->OutStreamer->emitLabel(Res);
+    return Res;
+  }
+
+  return nullptr;
+}
+
+void DwarfEmitterImpl::emitAbbrevs(
+    const SmallVector<std::unique_ptr<DIEAbbrev>> &Abbrevs,
+    unsigned DwarfVersion) {
+  MS->switchSection(MOFI->getDwarfAbbrevSection());
+  MC->setDwarfVersion(DwarfVersion);
+  Asm->emitDwarfAbbrevs(Abbrevs);
+}
+
+void DwarfEmitterImpl::emitCompileUnitHeader(DwarfUnit &Unit) {
+  MS->switchSection(MOFI->getDwarfInfoSection());
+  MC->setDwarfVersion(Unit.getVersion());
+
+  // Emit size of content not including length itself. The size has already
+  // been computed in CompileUnit::computeOffsets(). Subtract 4 to that size to
+  // account for the length field.
+  Asm->emitInt32(Unit.getDebugInfoHeaderSize() +
+                 Unit.getOutUnitDIE()->getSize() - 4);
+  Asm->emitInt16(Unit.getVersion());
+
+  if (Unit.getVersion() >= 5) {
+    Asm->emitInt8(dwarf::DW_UT_compile);
+    Asm->emitInt8(Unit.getFormParams().AddrSize);
+    // Proper offset to the abbreviations table will be set later.
+    Asm->emitInt32(0);
+    DebugInfoSectionSize += 12;
+  } else {
+    // Proper offset to the abbreviations table will be set later.
+    Asm->emitInt32(0);
+    Asm->emitInt8(Unit.getFormParams().AddrSize);
+    DebugInfoSectionSize += 11;
+  }
+}
+
+void DwarfEmitterImpl::emitDIE(DIE &Die) {
+  MS->switchSection(MOFI->getDwarfInfoSection());
+  Asm->emitDwarfDIE(Die);
+  DebugInfoSectionSize += Die.getSize();
+}
+
 } // end of namespace dwarflinker_parallel
 } // namespace llvm

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.h b/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.h
index d07397a304196e..3a8aab1ca83dc9 100644
--- a/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.h
+++ b/llvm/lib/DWARFLinkerParallel/DWARFEmitterImpl.h
@@ -14,7 +14,6 @@
 #include "llvm/CodeGen/AccelTable.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/DWARFLinkerParallel/DWARFLinker.h"
-#include "llvm/DWARFLinkerParallel/StringTable.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCInstrInfo.h"
@@ -40,186 +39,66 @@ class DWARFDebugMacro;
 
 namespace dwarflinker_parallel {
 
-struct UnitStartSymbol {
-  unsigned UnitID = 0;
-  MCSymbol *Symbol = 0;
-};
-using UnitStartSymbolsTy = SmallVector<UnitStartSymbol>;
-using Offset2UnitMapTy = DenseMap<uint64_t, CompileUnit *>;
-
-struct RangeAttrPatch;
-struct LocAttrPatch;
-
-/// The Dwarf emission logic.
-///
-/// All interactions with the MC layer that is used to build the debug
-/// information binary representation are handled in this class.
+/// This class emits DWARF data to the output stream. It emits already
+/// generated section data and specific data, which could not be generated
+/// by CompileUnit.
 class DwarfEmitterImpl : public ExtraDwarfEmitter {
 public:
   DwarfEmitterImpl(DWARFLinker::OutputFileType OutFileType,
-                   raw_pwrite_stream &OutFile,
-                   std::function<StringRef(StringRef Input)> Translator,
-                   DWARFLinker::MessageHandlerTy Warning)
-      : OutFile(OutFile), OutFileType(OutFileType), Translator(Translator),
-        WarningHandler(Warning) {}
+                   raw_pwrite_stream &OutFile)
+      : OutFile(OutFile), OutFileType(OutFileType) {}
 
+  /// Initialize AsmPrinter data.
   Error init(Triple TheTriple, StringRef Swift5ReflectionSegmentName);
 
+  /// Returns triple of output stream.
+  const Triple &getTargetTriple() { return MC->getTargetTriple(); }
+
   /// Dump the file to the disk.
   void finish() override { MS->finish(); }
 
+  /// Returns AsmPrinter.
   AsmPrinter &getAsmPrinter() const override { return *Asm; }
 
-  /// Set the current output section to debug_info and change
-  /// the MC Dwarf version to \p DwarfVersion.
-  void switchToDebugInfoSection(unsigned DwarfVersion) {}
-
   /// Emit the swift_ast section stored in \p Buffer.
-  void emitSwiftAST(StringRef Buffer) override {}
+  void emitSwiftAST(StringRef Buffer) override;
 
   /// Emit the swift reflection section stored in \p Buffer.
   void emitSwiftReflectionSection(
       llvm::binaryformat::Swift5ReflectionSectionKind ReflSectionKind,
-      StringRef Buffer, uint32_t Alignment, uint32_t Size) override {}
+      StringRef Buffer, uint32_t Alignment, uint32_t) override;
 
-  void emitPaperTrailWarningsDie(DIE &Die) {}
+  /// Emit specified section data.
+  void emitSectionContents(StringRef SecData, StringRef SecName) override;
 
-  void emitSectionContents(StringRef SecData, StringRef SecName) override {}
-
-  MCSymbol *emitTempSym(StringRef SecName, StringRef SymName) override {
-    return nullptr;
-  }
+  /// Emit temporary symbol.
+  MCSymbol *emitTempSym(StringRef SecName, StringRef SymName) override;
 
+  /// Emit abbreviations.
   void emitAbbrevs(const SmallVector<std::unique_ptr<DIEAbbrev>> &Abbrevs,
-                   unsigned DwarfVersion) {}
-
-  void emitStrings(const StringTable &Strings) {}
-
-  void emitLineStrings(const StringTable &Strings) {}
-
-  void emitDebugNames(AccelTable<DWARF5AccelTableStaticData> &,
-                      UnitStartSymbolsTy &UnitOffsets) {}
-
-  void emitAppleNamespaces(AccelTable<AppleAccelTableStaticOffsetData> &) {}
-
-  void emitAppleNames(AccelTable<AppleAccelTableStaticOffsetData> &) {}
-
-  void emitAppleObjc(AccelTable<AppleAccelTableStaticOffsetData> &) {}
-
-  void emitAppleTypes(AccelTable<AppleAccelTableStaticTypeData> &) {}
-
-  MCSymbol *emitDwarfDebugRangeListHeader(const CompileUnit &Unit) {
-    return nullptr;
-  }
-
-  void emitDwarfDebugRangeListFragment(const CompileUnit &Unit,
-                                       const AddressRanges &LinkedRanges,
-                                       RangeAttrPatch &Patch) {}
-
-  void emitDwarfDebugRangeListFooter(const CompileUnit &Unit,
-                                     MCSymbol *EndLabel) {}
-
-  MCSymbol *emitDwarfDebugLocListHeader(const CompileUnit &Unit) {
-    return nullptr;
-  }
-
-  void emitDwarfDebugLocListFragment(
-      const CompileUnit &Unit,
-      const DWARFLocationExpressionsVector &LinkedLocationExpression,
-      LocAttrPatch &Patch) {}
-
-  void emitDwarfDebugLocListFooter(const CompileUnit &Unit,
-                                   MCSymbol *EndLabel) {}
-
-  void emitDwarfDebugArangesTable(const CompileUnit &Unit,
-                                  const AddressRanges &LinkedRanges) {}
-
-  void translateLineTable(DataExtractor LineData, uint64_t Offset) {}
-
-  void emitLineTableForUnit(MCDwarfLineTableParams Params,
-                            StringRef PrologueBytes, unsigned MinInstLength,
-                            std::vector<DWARFDebugLine::Row> &Rows,
-                            unsigned AdddressSize) {}
+                   unsigned DwarfVersion);
 
-  void emitLineTableForUnit(const DWARFDebugLine::LineTable &LineTable,
-                            const CompileUnit &Unit, const StringTable &Strings,
-                            const StringTable &LineTableStrings) {}
+  /// Emit compile unit header.
+  void emitCompileUnitHeader(DwarfUnit &Unit);
 
-  void emitPubNamesForUnit(const CompileUnit &Unit) {}
-
-  void emitPubTypesForUnit(const CompileUnit &Unit) {}
-
-  void emitCIE(StringRef CIEBytes) {}
-
-  void emitFDE(uint32_t CIEOffset, uint32_t AddreSize, uint64_t Address,
-               StringRef Bytes) {}
-
-  void emitCompileUnitHeader(CompileUnit &Unit, unsigned DwarfVersion) {}
-
-  void emitDIE(DIE &Die) {}
-
-  void emitMacroTables(DWARFContext *Context,
-                       const Offset2UnitMapTy &UnitMacroMap,
-                       StringTable &Strings) {}
-
-  /// Returns size of generated .debug_line section.
-  uint64_t getDebugLineSectionSize() const { return LineSectionSize; }
-
-  /// Returns size of generated .debug_frame section.
-  uint64_t getDebugFrameSectionSize() const { return FrameSectionSize; }
-
-  /// Returns size of generated .debug_ranges section.
-  uint64_t getDebugRangesSectionSize() const { return RangesSectionSize; }
-
-  /// Returns size of generated .debug_rnglists section.
-  uint64_t getDebugRngListsSectionSize() const { return RngListsSectionSize; }
+  /// Emit DIE recursively.
+  void emitDIE(DIE &Die);
 
   /// Returns size of generated .debug_info section.
   uint64_t getDebugInfoSectionSize() const { return DebugInfoSectionSize; }
 
-  /// Returns size of generated .debug_macinfo section.
-  uint64_t getDebugMacInfoSectionSize() const { return MacInfoSectionSize; }
-
-  /// Returns size of generated .debug_macro section.
-  uint64_t getDebugMacroSectionSize() const { return MacroSectionSize; }
-
-  /// Returns size of generated .debug_loc section.
-  uint64_t getDebugLocSectionSize() const { return LocSectionSize; }
-
-  /// Returns size of generated .debug_loclists section.
-  uint64_t getDebugLocListsSectionSize() const { return LocListsSectionSize; }
-
 private:
-  inline void warn(const Twine &Warning, StringRef Context = "") {
-    if (WarningHandler)
-      WarningHandler(Warning, Context, nullptr);
-  }
-
-  void emitMacroTableImpl(const DWARFDebugMacro *MacroTable,
-                          const Offset2UnitMapTy &UnitMacroMap,
-                          StringPool &StringPool, uint64_t &OutOffset) {}
-
-  /// Emit piece of .debug_ranges for \p LinkedRanges.
-  void emitDwarfDebugRangesTableFragment(const CompileUnit &Unit,
-                                         const AddressRanges &LinkedRanges,
-                                         RangeAttrPatch &Patch) {}
-
-  /// Emit piece of .debug_rnglists for \p LinkedRanges.
-  void emitDwarfDebugRngListsTableFragment(const CompileUnit &Unit,
-                                           const AddressRanges &LinkedRanges,
-                                           RangeAttrPatch &Patch) {}
-
-  /// Emit piece of .debug_loc for \p LinkedRanges.
-  void emitDwarfDebugLocTableFragment(
-      const CompileUnit &Unit,
-      const DWARFLocationExpressionsVector &LinkedLocationExpression,
-      LocAttrPatch &Patch) {}
-
-  /// Emit piece of .debug_loclists for \p LinkedRanges.
-  void emitDwarfDebugLocListsTableFragment(
-      const CompileUnit &Unit,
-      const DWARFLocationExpressionsVector &LinkedLocationExpression,
-      LocAttrPatch &Patch) {}
+  // Enumerate all string patches and write them into the destination section.
+  // Order of patches is the same as in original input file. To avoid emitting
+  // the same string twice we accumulate NextOffset value. Thus if string
+  // offset smaller than NextOffset value then the patch is skipped (as that
+  // string was emitted earlier).
+  template <typename PatchTy>
+  void emitStringsImpl(ArrayList<PatchTy> &StringPatches,
+                       const StringEntryToDwarfStringPoolEntryMap &Strings,
+                       uint64_t &NextOffset, MCSection *OutSection);
+
+  MCSection *switchSection(StringRef SecName);
 
   /// \defgroup MCObjects MC layer objects constructed by the streamer
   /// @{
@@ -240,32 +119,8 @@ class DwarfEmitterImpl : public ExtraDwarfEmitter {
   /// The output file we stream the linked Dwarf to.
   raw_pwrite_stream &OutFile;
   DWARFLinker::OutputFileType OutFileType = DWARFLinker::OutputFileType::Object;
-  std::function<StringRef(StringRef Input)> Translator;
 
-  uint64_t RangesSectionSize = 0;
-  uint64_t RngListsSectionSize = 0;
-  uint64_t LocSectionSize = 0;
-  uint64_t LocListsSectionSize = 0;
-  uint64_t LineSectionSize = 0;
-  uint64_t FrameSectionSize = 0;
   uint64_t DebugInfoSectionSize = 0;
-  uint64_t MacInfoSectionSize = 0;
-  uint64_t MacroSectionSize = 0;
-
-  /// Keep track of emitted CUs and their Unique ID.
-  struct EmittedUnit {
-    unsigned ID;
-    MCSymbol *LabelBegin;
-  };
-  std::vector<EmittedUnit> EmittedUnitsTy;
-
-  /// Emit the pubnames or pubtypes section contribution for \p
-  /// Unit into \p Sec. The data is provided in \p Names.
-  void emitPubSectionForUnit(MCSection *Sec, StringRef Name,
-                             const CompileUnit &Unit,
-                             const std::vector<CompileUnit::AccelInfo> &Names);
-
-  DWARFLinker::MessageHandlerTy WarningHandler = nullptr;
 };
 
 } // end namespace dwarflinker_parallel

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFFile.cpp b/llvm/lib/DWARFLinkerParallel/DWARFFile.cpp
new file mode 100644
index 00000000000000..86c7e816ead8fe
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DWARFFile.cpp
@@ -0,0 +1,18 @@
+//=== DWARFFile.cpp -------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DWARFLinkerParallel/DWARFFile.h"
+#include "DWARFLinkerGlobalData.h"
+
+llvm::dwarflinker_parallel::DWARFFile::DWARFFile(
+    StringRef Name, std::unique_ptr<DWARFContext> Dwarf,
+    std::unique_ptr<AddressesMap> Addresses,
+    const std::vector<std::string> &Warnings,
+    DWARFFile::UnloadCallbackTy UnloadFunc)
+    : FileName(Name), Dwarf(std::move(Dwarf)), Addresses(std::move(Addresses)),
+      Warnings(Warnings), UnloadFunc(UnloadFunc) {}

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.cpp b/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.cpp
new file mode 100644
index 00000000000000..783d9ea0d4954d
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.cpp
@@ -0,0 +1,1396 @@
+//=== DWARFLinkerCompileUnit.cpp ------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFLinkerCompileUnit.h"
+#include "DIEAttributeCloner.h"
+#include "DIEGenerator.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/FormatVariadic.h"
+
+using namespace llvm;
+using namespace llvm::dwarflinker_parallel;
+
+void CompileUnit::loadLineTable() {
+  LineTablePtr = File.Dwarf->getLineTableForUnit(&getOrigUnit());
+}
+
+void CompileUnit::maybeResetToLoadedStage() {
+  if (getStage() <= Stage::Loaded)
+    return;
+
+  for (DIEInfo &DieInfo : DieInfoArray)
+    DieInfo.unsetFlagsWhichSetDuringLiveAnalysis();
+
+  LowPc = std::nullopt;
+  HighPc = 0;
+  Labels.clear();
+  Ranges.clear();
+
+  if (getStage() < Stage::Cloned) {
+    setStage(Stage::Loaded);
+    return;
+  }
+
+  AbbreviationsSet.clear();
+  Abbreviations.clear();
+  OutUnitDIE = nullptr;
+  DebugAddrIndexMap.clear();
+
+  for (uint64_t &Offset : OutDieOffsetArray)
+    Offset = 0;
+  eraseSections();
+
+  setStage(Stage::CreatedNotLoaded);
+}
+
+bool CompileUnit::loadInputDIEs() {
+  DWARFDie InputUnitDIE = getUnitDIE(false);
+  if (!InputUnitDIE)
+    return false;
+
+  // load input dies, resize Info structures array.
+  DieInfoArray.resize(getOrigUnit().getNumDIEs());
+  OutDieOffsetArray.resize(getOrigUnit().getNumDIEs(), 0);
+  return true;
+}
+
+void CompileUnit::analyzeDWARFStructureRec(const DWARFDebugInfoEntry *DieEntry,
+                                           bool IsInModule, bool IsInFunction) {
+  for (const DWARFDebugInfoEntry *CurChild = getFirstChildEntry(DieEntry);
+       CurChild && CurChild->getAbbreviationDeclarationPtr();
+       CurChild = getSiblingEntry(CurChild)) {
+    CompileUnit::DIEInfo &ChildInfo = getDIEInfo(CurChild);
+
+    if (IsInModule)
+      ChildInfo.setIsInMouduleScope();
+    if (IsInFunction)
+      ChildInfo.setIsInFunctionScope();
+
+    switch (CurChild->getTag()) {
+    case dwarf::DW_TAG_module:
+      ChildInfo.setIsInMouduleScope();
+      if (DieEntry->getTag() == dwarf::DW_TAG_compile_unit &&
+          dwarf::toString(find(CurChild, dwarf::DW_AT_name), "") !=
+              getClangModuleName())
+        analyzeImportedModule(CurChild);
+      break;
+    case dwarf::DW_TAG_subprogram:
+      ChildInfo.setIsInFunctionScope();
+      break;
+    default:
+      break;
+    }
+
+    if (IsInModule)
+      ChildInfo.setIsInMouduleScope();
+    if (IsInFunction)
+      ChildInfo.setIsInFunctionScope();
+
+    if (CurChild->hasChildren())
+      analyzeDWARFStructureRec(CurChild, ChildInfo.getIsInMouduleScope(),
+                               ChildInfo.getIsInFunctionScope());
+  }
+}
+
+StringEntry *CompileUnit::getFileName(unsigned FileIdx,
+                                      StringPool &GlobalStrings) {
+  if (LineTablePtr) {
+    if (LineTablePtr->hasFileAtIndex(FileIdx)) {
+      // Cache the resolved paths based on the index in the line table,
+      // because calling realpath is expensive.
+      ResolvedPathsMap::const_iterator It = ResolvedFullPaths.find(FileIdx);
+      if (It == ResolvedFullPaths.end()) {
+        std::string OrigFileName;
+        bool FoundFileName = LineTablePtr->getFileNameByIndex(
+            FileIdx, getOrigUnit().getCompilationDir(),
+            DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
+            OrigFileName);
+        (void)FoundFileName;
+        assert(FoundFileName && "Must get file name from line table");
+
+        // Second level of caching, this time based on the file's parent
+        // path.
+        StringRef FileName = sys::path::filename(OrigFileName);
+        StringRef ParentPath = sys::path::parent_path(OrigFileName);
+
+        // If the ParentPath has not yet been resolved, resolve and cache it for
+        // future look-ups.
+        StringMap<StringEntry *>::iterator ParentIt =
+            ResolvedParentPaths.find(ParentPath);
+        if (ParentIt == ResolvedParentPaths.end()) {
+          SmallString<256> RealPath;
+          sys::fs::real_path(ParentPath, RealPath);
+          ParentIt =
+              ResolvedParentPaths
+                  .insert({ParentPath, GlobalStrings.insert(RealPath).first})
+                  .first;
+        }
+
+        // Join the file name again with the resolved path.
+        SmallString<256> ResolvedPath(ParentIt->second->first());
+        sys::path::append(ResolvedPath, FileName);
+
+        It = ResolvedFullPaths
+                 .insert(std::make_pair(
+                     FileIdx, GlobalStrings.insert(ResolvedPath).first))
+                 .first;
+      }
+
+      return It->second;
+    }
+  }
+
+  return nullptr;
+}
+
+void CompileUnit::cleanupDataAfterClonning() {
+  AbbreviationsSet.clear();
+  ResolvedFullPaths.shrink_and_clear();
+  ResolvedParentPaths.clear();
+  DieInfoArray = SmallVector<DIEInfo>();
+  OutDieOffsetArray = SmallVector<uint64_t>();
+  getOrigUnit().clear();
+}
+
+/// Collect references to parseable Swift interfaces in imported
+/// DW_TAG_module blocks.
+void CompileUnit::analyzeImportedModule(const DWARFDebugInfoEntry *DieEntry) {
+  if (getLanguage() != dwarf::DW_LANG_Swift)
+    return;
+
+  if (!GlobalData.getOptions().ParseableSwiftInterfaces)
+    return;
+
+  StringRef Path =
+      dwarf::toStringRef(find(DieEntry, dwarf::DW_AT_LLVM_include_path));
+  if (!Path.endswith(".swiftinterface"))
+    return;
+  // Don't track interfaces that are part of the SDK.
+  StringRef SysRoot =
+      dwarf::toStringRef(find(DieEntry, dwarf::DW_AT_LLVM_sysroot));
+  if (SysRoot.empty())
+    SysRoot = getSysRoot();
+  if (!SysRoot.empty() && Path.startswith(SysRoot))
+    return;
+  if (std::optional<DWARFFormValue> Val = find(DieEntry, dwarf::DW_AT_name)) {
+    Expected<const char *> Name = Val->getAsCString();
+    if (!Name) {
+      warn(Name.takeError());
+      return;
+    }
+
+    auto &Entry = (*GlobalData.getOptions().ParseableSwiftInterfaces)[*Name];
+    // The prepend path is applied later when copying.
+    SmallString<128> ResolvedPath;
+    if (sys::path::is_relative(Path))
+      sys::path::append(
+          ResolvedPath,
+          dwarf::toString(getUnitDIE().find(dwarf::DW_AT_comp_dir), ""));
+    sys::path::append(ResolvedPath, Path);
+    if (!Entry.empty() && Entry != ResolvedPath) {
+      DWARFDie Die = getDIE(DieEntry);
+      warn(Twine("conflicting parseable interfaces for Swift Module ") + *Name +
+               ": " + Entry + " and " + Path + ".",
+           &Die);
+    }
+    Entry = std::string(ResolvedPath.str());
+  }
+}
+
+void CompileUnit::updateDieRefPatchesWithClonedOffsets() {
+  if (std::optional<SectionDescriptor *> DebugInfoSection =
+          getSectionDescriptor(DebugSectionKind::DebugInfo)) {
+
+    (*DebugInfoSection)
+        ->ListDebugDieRefPatch.forEach([](DebugDieRefPatch &Patch) {
+          Patch.RefDieIdxOrClonedOffset =
+              Patch.RefCU.getPointer()->getDieOutOffset(
+                  Patch.RefDieIdxOrClonedOffset);
+        });
+
+    (*DebugInfoSection)
+        ->ListDebugULEB128DieRefPatch.forEach(
+            [](DebugULEB128DieRefPatch &Patch) {
+              Patch.RefDieIdxOrClonedOffset =
+                  Patch.RefCU.getPointer()->getDieOutOffset(
+                      Patch.RefDieIdxOrClonedOffset);
+            });
+  }
+
+  if (std::optional<SectionDescriptor *> DebugLocSection =
+          getSectionDescriptor(DebugSectionKind::DebugLoc)) {
+    (*DebugLocSection)
+        ->ListDebugULEB128DieRefPatch.forEach(
+            [](DebugULEB128DieRefPatch &Patch) {
+              Patch.RefDieIdxOrClonedOffset =
+                  Patch.RefCU.getPointer()->getDieOutOffset(
+                      Patch.RefDieIdxOrClonedOffset);
+            });
+  }
+
+  if (std::optional<SectionDescriptor *> DebugLocListsSection =
+          getSectionDescriptor(DebugSectionKind::DebugLocLists)) {
+    (*DebugLocListsSection)
+        ->ListDebugULEB128DieRefPatch.forEach(
+            [](DebugULEB128DieRefPatch &Patch) {
+              Patch.RefDieIdxOrClonedOffset =
+                  Patch.RefCU.getPointer()->getDieOutOffset(
+                      Patch.RefDieIdxOrClonedOffset);
+            });
+  }
+}
+
+std::optional<std::pair<CompileUnit *, uint32_t>>
+CompileUnit::resolveDIEReference(const DWARFFormValue &RefValue) {
+  if (std::optional<DWARFFormValue::UnitOffset> Ref =
+          *RefValue.getAsRelativeReference()) {
+    if (Ref->Unit != nullptr) {
+      // Referenced DIE is in current compile unit.
+
+      if (std::optional<uint32_t> RefDieIdx =
+              getDIEIndexForOffset(Ref->Unit->getOffset() + Ref->Offset))
+        return std::make_pair(this, *RefDieIdx);
+    } else if (CompileUnit *RefCU = getUnitFromOffset(Ref->Offset)) {
+      // Referenced DIE is in other compile unit.
+
+      // Check whether DIEs are loaded for that compile unit.
+      enum Stage ReferredCUStage = RefCU->getStage();
+      if (ReferredCUStage < Stage::Loaded || ReferredCUStage > Stage::Cloned)
+        return std::make_pair(RefCU, 0);
+
+      if (std::optional<uint32_t> RefDieIdx =
+              RefCU->getDIEIndexForOffset(Ref->Offset))
+        return std::make_pair(RefCU, *RefDieIdx);
+    }
+  }
+
+  return std::nullopt;
+}
+
+void CompileUnit::addFunctionRange(uint64_t FuncLowPc, uint64_t FuncHighPc,
+                                   int64_t PcOffset) {
+  std::lock_guard<std::mutex> Guard(RangesMutex);
+
+  Ranges.insert({FuncLowPc, FuncHighPc}, PcOffset);
+  if (LowPc)
+    LowPc = std::min(*LowPc, FuncLowPc + PcOffset);
+  else
+    LowPc = FuncLowPc + PcOffset;
+  this->HighPc = std::max(HighPc, FuncHighPc + PcOffset);
+}
+
+void CompileUnit::addLabelLowPc(uint64_t LabelLowPc, int64_t PcOffset) {
+  std::lock_guard<std::mutex> Guard(LabelsMutex);
+  Labels.insert({LabelLowPc, PcOffset});
+}
+
+Error CompileUnit::cloneAndEmitDebugLocations() {
+  if (getGlobalData().getOptions().UpdateIndexTablesOnly)
+    return Error::success();
+
+  if (getOrigUnit().getVersion() < 5) {
+    emitLocations(DebugSectionKind::DebugLoc);
+    return Error::success();
+  }
+
+  emitLocations(DebugSectionKind::DebugLocLists);
+  return Error::success();
+}
+
+void CompileUnit::emitLocations(DebugSectionKind LocationSectionKind) {
+  SectionDescriptor &DebugInfoSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo);
+
+  if (!DebugInfoSection.ListDebugLocPatch.empty()) {
+    SectionDescriptor &OutLocationSection =
+        getOrCreateSectionDescriptor(LocationSectionKind);
+    DWARFUnit &OrigUnit = getOrigUnit();
+
+    uint64_t OffsetAfterUnitLength = emitLocListHeader(OutLocationSection);
+
+    DebugInfoSection.ListDebugLocPatch.forEach([&](DebugLocPatch &Patch) {
+      // Get location expressions vector corresponding to the current
+      // attribute from the source DWARF.
+      uint64_t InputDebugLocSectionOffset = DebugInfoSection.getIntVal(
+          Patch.PatchOffset,
+          DebugInfoSection.getFormParams().getDwarfOffsetByteSize());
+      Expected<DWARFLocationExpressionsVector> OriginalLocations =
+          OrigUnit.findLoclistFromOffset(InputDebugLocSectionOffset);
+
+      if (!OriginalLocations) {
+        warn(OriginalLocations.takeError());
+        return;
+      }
+
+      LinkedLocationExpressionsVector LinkedLocationExpressions;
+      for (DWARFLocationExpression &CurExpression : *OriginalLocations) {
+        LinkedLocationExpressionsWithOffsetPatches LinkedExpression;
+
+        if (CurExpression.Range) {
+          // Relocate address range.
+          LinkedExpression.Expression.Range = {
+              CurExpression.Range->LowPC + Patch.AddrAdjustmentValue,
+              CurExpression.Range->HighPC + Patch.AddrAdjustmentValue};
+        }
+
+        DataExtractor Data(CurExpression.Expr, OrigUnit.isLittleEndian(),
+                           OrigUnit.getAddressByteSize());
+
+        DWARFExpression InputExpression(Data, OrigUnit.getAddressByteSize(),
+                                        OrigUnit.getFormParams().Format);
+        cloneDieAttrExpression(InputExpression,
+                               LinkedExpression.Expression.Expr,
+                               OutLocationSection, Patch.AddrAdjustmentValue,
+                               LinkedExpression.Patches);
+
+        LinkedLocationExpressions.push_back({LinkedExpression});
+      }
+
+      // Emit locations list table fragment corresponding to the CurLocAttr.
+      DebugInfoSection.apply(Patch.PatchOffset, dwarf::DW_FORM_sec_offset,
+                             OutLocationSection.OS.tell());
+      emitLocListFragment(LinkedLocationExpressions, OutLocationSection);
+    });
+
+    if (OffsetAfterUnitLength > 0) {
+      assert(OffsetAfterUnitLength -
+                 OutLocationSection.getFormParams().getDwarfOffsetByteSize() <
+             OffsetAfterUnitLength);
+      OutLocationSection.apply(
+          OffsetAfterUnitLength -
+              OutLocationSection.getFormParams().getDwarfOffsetByteSize(),
+          dwarf::DW_FORM_sec_offset,
+          OutLocationSection.OS.tell() - OffsetAfterUnitLength);
+    }
+  }
+}
+
+/// Emit debug locations(.debug_loc, .debug_loclists) header.
+uint64_t CompileUnit::emitLocListHeader(SectionDescriptor &OutLocationSection) {
+  if (getOrigUnit().getVersion() < 5)
+    return 0;
+
+  // unit_length.
+  OutLocationSection.emitUnitLength(0xBADDEF);
+  uint64_t OffsetAfterUnitLength = OutLocationSection.OS.tell();
+
+  // Version.
+  OutLocationSection.emitIntVal(5, 2);
+
+  // Address size.
+  OutLocationSection.emitIntVal(OutLocationSection.getFormParams().AddrSize, 1);
+
+  // Seg_size
+  OutLocationSection.emitIntVal(0, 1);
+
+  // Offset entry count
+  OutLocationSection.emitIntVal(0, 4);
+
+  return OffsetAfterUnitLength;
+}
+
+/// Emit debug locations(.debug_loc, .debug_loclists) fragment.
+uint64_t CompileUnit::emitLocListFragment(
+    const LinkedLocationExpressionsVector &LinkedLocationExpression,
+    SectionDescriptor &OutLocationSection) {
+  uint64_t OffsetBeforeLocationExpression = 0;
+
+  if (getOrigUnit().getVersion() < 5) {
+    uint64_t BaseAddress = 0;
+    if (std::optional<uint64_t> LowPC = getLowPc())
+      BaseAddress = *LowPC;
+
+    for (const LinkedLocationExpressionsWithOffsetPatches &LocExpression :
+         LinkedLocationExpression) {
+      if (LocExpression.Expression.Range) {
+        OutLocationSection.emitIntVal(
+            LocExpression.Expression.Range->LowPC - BaseAddress,
+            OutLocationSection.getFormParams().AddrSize);
+        OutLocationSection.emitIntVal(
+            LocExpression.Expression.Range->HighPC - BaseAddress,
+            OutLocationSection.getFormParams().AddrSize);
+      }
+
+      OutLocationSection.emitIntVal(LocExpression.Expression.Expr.size(), 2);
+      OffsetBeforeLocationExpression = OutLocationSection.OS.tell();
+      for (uint64_t *OffsetPtr : LocExpression.Patches)
+        *OffsetPtr += OffsetBeforeLocationExpression;
+
+      OutLocationSection.OS
+          << StringRef((const char *)LocExpression.Expression.Expr.data(),
+                       LocExpression.Expression.Expr.size());
+    }
+
+    // Emit the terminator entry.
+    OutLocationSection.emitIntVal(0,
+                                  OutLocationSection.getFormParams().AddrSize);
+    OutLocationSection.emitIntVal(0,
+                                  OutLocationSection.getFormParams().AddrSize);
+    return OffsetBeforeLocationExpression;
+  }
+
+  std::optional<uint64_t> BaseAddress;
+  for (const LinkedLocationExpressionsWithOffsetPatches &LocExpression :
+       LinkedLocationExpression) {
+    if (LocExpression.Expression.Range) {
+      // Check whether base address is set. If it is not set yet
+      // then set current base address and emit base address selection entry.
+      if (!BaseAddress) {
+        BaseAddress = LocExpression.Expression.Range->LowPC;
+
+        // Emit base address.
+        OutLocationSection.emitIntVal(dwarf::DW_LLE_base_addressx, 1);
+        encodeULEB128(DebugAddrIndexMap.getValueIndex(*BaseAddress),
+                      OutLocationSection.OS);
+      }
+
+      // Emit type of entry.
+      OutLocationSection.emitIntVal(dwarf::DW_LLE_offset_pair, 1);
+
+      // Emit start offset relative to base address.
+      encodeULEB128(LocExpression.Expression.Range->LowPC - *BaseAddress,
+                    OutLocationSection.OS);
+
+      // Emit end offset relative to base address.
+      encodeULEB128(LocExpression.Expression.Range->HighPC - *BaseAddress,
+                    OutLocationSection.OS);
+    } else
+      // Emit type of entry.
+      OutLocationSection.emitIntVal(dwarf::DW_LLE_default_location, 1);
+
+    encodeULEB128(LocExpression.Expression.Expr.size(), OutLocationSection.OS);
+    OffsetBeforeLocationExpression = OutLocationSection.OS.tell();
+    for (uint64_t *OffsetPtr : LocExpression.Patches)
+      *OffsetPtr += OffsetBeforeLocationExpression;
+
+    OutLocationSection.OS << StringRef(
+        (const char *)LocExpression.Expression.Expr.data(),
+        LocExpression.Expression.Expr.size());
+  }
+
+  // Emit the terminator entry.
+  OutLocationSection.emitIntVal(dwarf::DW_LLE_end_of_list, 1);
+  return OffsetBeforeLocationExpression;
+}
+
+Error CompileUnit::emitDebugAddrSection() {
+  if (GlobalData.getOptions().UpdateIndexTablesOnly)
+    return Error::success();
+
+  if (getVersion() < 5)
+    return Error::success();
+
+  if (DebugAddrIndexMap.empty())
+    return Error::success();
+
+  SectionDescriptor &OutAddrSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugAddr);
+
+  // Emit section header.
+
+  //   Emit length.
+  OutAddrSection.emitUnitLength(0xBADDEF);
+  uint64_t OffsetAfterSectionLength = OutAddrSection.OS.tell();
+
+  //   Emit version.
+  OutAddrSection.emitIntVal(5, 2);
+
+  //   Emit address size.
+  OutAddrSection.emitIntVal(getFormParams().AddrSize, 1);
+
+  //   Emit segment size.
+  OutAddrSection.emitIntVal(0, 1);
+
+  // Emit addresses.
+  for (uint64_t AddrValue : DebugAddrIndexMap.getValues())
+    OutAddrSection.emitIntVal(AddrValue, getFormParams().AddrSize);
+
+  // Patch section length.
+  OutAddrSection.apply(
+      OffsetAfterSectionLength -
+          OutAddrSection.getFormParams().getDwarfOffsetByteSize(),
+      dwarf::DW_FORM_sec_offset,
+      OutAddrSection.OS.tell() - OffsetAfterSectionLength);
+
+  return Error::success();
+}
+
+Error CompileUnit::emitDebugStringOffsetSection() {
+  if (getVersion() < 5)
+    return Error::success();
+
+  if (DebugStringIndexMap.empty())
+    return Error::success();
+
+  SectionDescriptor &OutDebugStrOffsetsSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugStrOffsets);
+
+  // Emit section header.
+
+  //   Emit length.
+  OutDebugStrOffsetsSection.emitUnitLength(0xBADDEF);
+  uint64_t OffsetAfterSectionLength = OutDebugStrOffsetsSection.OS.tell();
+
+  //   Emit version.
+  OutDebugStrOffsetsSection.emitIntVal(5, 2);
+
+  //   Emit padding.
+  OutDebugStrOffsetsSection.emitIntVal(0, 2);
+
+  //   Emit index to offset map.
+  for (const StringEntry *String : DebugStringIndexMap.getValues()) {
+    // Note patch for string offset value.
+    OutDebugStrOffsetsSection.notePatch(
+        DebugStrPatch{{OutDebugStrOffsetsSection.OS.tell()}, String});
+
+    // Emit placeholder for offset value.
+    OutDebugStrOffsetsSection.emitOffset(0xBADDEF);
+  }
+
+  // Patch section length.
+  OutDebugStrOffsetsSection.apply(
+      OffsetAfterSectionLength -
+          OutDebugStrOffsetsSection.getFormParams().getDwarfOffsetByteSize(),
+      dwarf::DW_FORM_sec_offset,
+      OutDebugStrOffsetsSection.OS.tell() - OffsetAfterSectionLength);
+
+  return Error::success();
+}
+
+Error CompileUnit::cloneAndEmitRanges() {
+  if (getGlobalData().getOptions().UpdateIndexTablesOnly)
+    return Error::success();
+
+  // Build set of linked address ranges for unit function ranges.
+  AddressRanges LinkedFunctionRanges;
+  for (const AddressRangeValuePair &Range : getFunctionRanges())
+    LinkedFunctionRanges.insert(
+        {Range.Range.start() + Range.Value, Range.Range.end() + Range.Value});
+
+  emitAranges(LinkedFunctionRanges);
+
+  if (getOrigUnit().getVersion() < 5) {
+    cloneAndEmitRangeList(DebugSectionKind::DebugRange, LinkedFunctionRanges);
+    return Error::success();
+  }
+
+  cloneAndEmitRangeList(DebugSectionKind::DebugRngLists, LinkedFunctionRanges);
+  return Error::success();
+}
+
+void CompileUnit::cloneAndEmitRangeList(DebugSectionKind RngSectionKind,
+                                        AddressRanges &LinkedFunctionRanges) {
+  SectionDescriptor &DebugInfoSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo);
+  SectionDescriptor &OutRangeSection =
+      getOrCreateSectionDescriptor(RngSectionKind);
+
+  if (!DebugInfoSection.ListDebugRangePatch.empty()) {
+    std::optional<AddressRangeValuePair> CachedRange;
+    uint64_t OffsetAfterUnitLength = emitRangeListHeader(OutRangeSection);
+
+    DebugRangePatch *CompileUnitRangePtr = nullptr;
+    DebugInfoSection.ListDebugRangePatch.forEach([&](DebugRangePatch &Patch) {
+      if (Patch.IsCompileUnitRanges) {
+        CompileUnitRangePtr = &Patch;
+      } else {
+        // Get ranges from the source DWARF corresponding to the current
+        // attribute.
+        AddressRanges LinkedRanges;
+        uint64_t InputDebugRangesSectionOffset = DebugInfoSection.getIntVal(
+            Patch.PatchOffset,
+            DebugInfoSection.getFormParams().getDwarfOffsetByteSize());
+        if (Expected<DWARFAddressRangesVector> InputRanges =
+                getOrigUnit().findRnglistFromOffset(
+                    InputDebugRangesSectionOffset)) {
+          // Apply relocation adjustment.
+          for (const auto &Range : *InputRanges) {
+            if (!CachedRange || !CachedRange->Range.contains(Range.LowPC))
+              CachedRange =
+                  getFunctionRanges().getRangeThatContains(Range.LowPC);
+
+            // All range entries should lie in the function range.
+            if (!CachedRange) {
+              warn("inconsistent range data.");
+              continue;
+            }
+
+            // Store range for emiting.
+            LinkedRanges.insert({Range.LowPC + CachedRange->Value,
+                                 Range.HighPC + CachedRange->Value});
+          }
+        } else {
+          llvm::consumeError(InputRanges.takeError());
+          warn("invalid range list ignored.");
+        }
+
+        // Emit linked ranges.
+        DebugInfoSection.apply(Patch.PatchOffset, dwarf::DW_FORM_sec_offset,
+                               OutRangeSection.OS.tell());
+        emitRangeListFragment(LinkedRanges, OutRangeSection);
+      }
+    });
+
+    if (CompileUnitRangePtr != nullptr) {
+      // Emit compile unit ranges last to be binary compatible with classic
+      // dsymutil.
+      DebugInfoSection.apply(CompileUnitRangePtr->PatchOffset,
+                             dwarf::DW_FORM_sec_offset,
+                             OutRangeSection.OS.tell());
+      emitRangeListFragment(LinkedFunctionRanges, OutRangeSection);
+    }
+
+    if (OffsetAfterUnitLength > 0) {
+      assert(OffsetAfterUnitLength -
+                 OutRangeSection.getFormParams().getDwarfOffsetByteSize() <
+             OffsetAfterUnitLength);
+      OutRangeSection.apply(
+          OffsetAfterUnitLength -
+              OutRangeSection.getFormParams().getDwarfOffsetByteSize(),
+          dwarf::DW_FORM_sec_offset,
+          OutRangeSection.OS.tell() - OffsetAfterUnitLength);
+    }
+  }
+}
+
+uint64_t CompileUnit::emitRangeListHeader(SectionDescriptor &OutRangeSection) {
+  if (OutRangeSection.getFormParams().Version < 5)
+    return 0;
+
+  // unit_length.
+  OutRangeSection.emitUnitLength(0xBADDEF);
+  uint64_t OffsetAfterUnitLength = OutRangeSection.OS.tell();
+
+  // Version.
+  OutRangeSection.emitIntVal(5, 2);
+
+  // Address size.
+  OutRangeSection.emitIntVal(OutRangeSection.getFormParams().AddrSize, 1);
+
+  // Seg_size
+  OutRangeSection.emitIntVal(0, 1);
+
+  // Offset entry count
+  OutRangeSection.emitIntVal(0, 4);
+
+  return OffsetAfterUnitLength;
+}
+
+void CompileUnit::emitRangeListFragment(const AddressRanges &LinkedRanges,
+                                        SectionDescriptor &OutRangeSection) {
+  if (OutRangeSection.getFormParams().Version < 5) {
+    // Emit ranges.
+    uint64_t BaseAddress = 0;
+    if (std::optional<uint64_t> LowPC = getLowPc())
+      BaseAddress = *LowPC;
+
+    for (const AddressRange &Range : LinkedRanges) {
+      OutRangeSection.emitIntVal(Range.start() - BaseAddress,
+                                 OutRangeSection.getFormParams().AddrSize);
+      OutRangeSection.emitIntVal(Range.end() - BaseAddress,
+                                 OutRangeSection.getFormParams().AddrSize);
+    }
+
+    // Add the terminator entry.
+    OutRangeSection.emitIntVal(0, OutRangeSection.getFormParams().AddrSize);
+    OutRangeSection.emitIntVal(0, OutRangeSection.getFormParams().AddrSize);
+    return;
+  }
+
+  std::optional<uint64_t> BaseAddress;
+  for (const AddressRange &Range : LinkedRanges) {
+    if (!BaseAddress) {
+      BaseAddress = Range.start();
+
+      // Emit base address.
+      OutRangeSection.emitIntVal(dwarf::DW_RLE_base_addressx, 1);
+      encodeULEB128(getDebugAddrIndex(*BaseAddress), OutRangeSection.OS);
+    }
+
+    // Emit type of entry.
+    OutRangeSection.emitIntVal(dwarf::DW_RLE_offset_pair, 1);
+
+    // Emit start offset relative to base address.
+    encodeULEB128(Range.start() - *BaseAddress, OutRangeSection.OS);
+
+    // Emit end offset relative to base address.
+    encodeULEB128(Range.end() - *BaseAddress, OutRangeSection.OS);
+  }
+
+  // Emit the terminator entry.
+  OutRangeSection.emitIntVal(dwarf::DW_RLE_end_of_list, 1);
+}
+
+void CompileUnit::emitAranges(AddressRanges &LinkedFunctionRanges) {
+  if (LinkedFunctionRanges.empty())
+    return;
+
+  SectionDescriptor &DebugInfoSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo);
+  SectionDescriptor &OutArangesSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugARanges);
+
+  // Emit Header.
+  unsigned HeaderSize =
+      sizeof(int32_t) + // Size of contents (w/o this field
+      sizeof(int16_t) + // DWARF ARange version number
+      sizeof(int32_t) + // Offset of CU in the .debug_info section
+      sizeof(int8_t) +  // Pointer Size (in bytes)
+      sizeof(int8_t);   // Segment Size (in bytes)
+
+  unsigned TupleSize = OutArangesSection.getFormParams().AddrSize * 2;
+  unsigned Padding = offsetToAlignment(HeaderSize, Align(TupleSize));
+
+  OutArangesSection.emitOffset(0xBADDEF); // Aranges length
+  uint64_t OffsetAfterArangesLengthField = OutArangesSection.OS.tell();
+
+  OutArangesSection.emitIntVal(dwarf::DW_ARANGES_VERSION, 2); // Version number
+  OutArangesSection.notePatch(
+      DebugOffsetPatch{OutArangesSection.OS.tell(), &DebugInfoSection});
+  OutArangesSection.emitOffset(0xBADDEF); // Corresponding unit's offset
+  OutArangesSection.emitIntVal(OutArangesSection.getFormParams().AddrSize,
+                               1);    // Address size
+  OutArangesSection.emitIntVal(0, 1); // Segment size
+
+  for (size_t Idx = 0; Idx < Padding; Idx++)
+    OutArangesSection.emitIntVal(0, 1); // Padding
+
+  // Emit linked ranges.
+  for (const AddressRange &Range : LinkedFunctionRanges) {
+    OutArangesSection.emitIntVal(Range.start(),
+                                 OutArangesSection.getFormParams().AddrSize);
+    OutArangesSection.emitIntVal(Range.end() - Range.start(),
+                                 OutArangesSection.getFormParams().AddrSize);
+  }
+
+  // Emit terminator.
+  OutArangesSection.emitIntVal(0, OutArangesSection.getFormParams().AddrSize);
+  OutArangesSection.emitIntVal(0, OutArangesSection.getFormParams().AddrSize);
+
+  uint64_t OffsetAfterArangesEnd = OutArangesSection.OS.tell();
+
+  // Update Aranges lentgh.
+  OutArangesSection.apply(
+      OffsetAfterArangesLengthField -
+          OutArangesSection.getFormParams().getDwarfOffsetByteSize(),
+      dwarf::DW_FORM_sec_offset,
+      OffsetAfterArangesEnd - OffsetAfterArangesLengthField);
+}
+
+Error CompileUnit::cloneAndEmitDebugMacro() {
+  if (getOutUnitDIE() == nullptr)
+    return Error::success();
+
+  DWARFUnit &OrigUnit = getOrigUnit();
+  DWARFDie OrigUnitDie = OrigUnit.getUnitDIE();
+
+  // Check for .debug_macro table.
+  if (std::optional<uint64_t> MacroAttr =
+          dwarf::toSectionOffset(OrigUnitDie.find(dwarf::DW_AT_macros))) {
+    if (const DWARFDebugMacro *Table =
+            getContaingFile().Dwarf->getDebugMacro()) {
+      emitMacroTableImpl(Table, *MacroAttr, true);
+    }
+  }
+
+  // Check for .debug_macinfo table.
+  if (std::optional<uint64_t> MacroAttr =
+          dwarf::toSectionOffset(OrigUnitDie.find(dwarf::DW_AT_macro_info))) {
+    if (const DWARFDebugMacro *Table =
+            getContaingFile().Dwarf->getDebugMacinfo()) {
+      emitMacroTableImpl(Table, *MacroAttr, false);
+    }
+  }
+
+  return Error::success();
+}
+
+void CompileUnit::emitMacroTableImpl(const DWARFDebugMacro *MacroTable,
+                                     uint64_t OffsetToMacroTable,
+                                     bool hasDWARFv5Header) {
+  SectionDescriptor &OutSection =
+      hasDWARFv5Header
+          ? getOrCreateSectionDescriptor(DebugSectionKind::DebugMacro)
+          : getOrCreateSectionDescriptor(DebugSectionKind::DebugMacinfo);
+
+  bool DefAttributeIsReported = false;
+  bool UndefAttributeIsReported = false;
+  bool ImportAttributeIsReported = false;
+
+  for (const DWARFDebugMacro::MacroList &List : MacroTable->MacroLists) {
+    if (OffsetToMacroTable == List.Offset) {
+      // Write DWARFv5 header.
+      if (hasDWARFv5Header) {
+        // Write header version.
+        OutSection.emitIntVal(List.Header.Version, sizeof(List.Header.Version));
+
+        uint8_t Flags = List.Header.Flags;
+
+        // Check for OPCODE_OPERANDS_TABLE.
+        if (Flags &
+            DWARFDebugMacro::HeaderFlagMask::MACRO_OPCODE_OPERANDS_TABLE) {
+          Flags &=
+              ~DWARFDebugMacro::HeaderFlagMask::MACRO_OPCODE_OPERANDS_TABLE;
+          warn("opcode_operands_table is not supported yet.");
+        }
+
+        // Check for DEBUG_LINE_OFFSET.
+        std::optional<uint64_t> StmtListOffset;
+        if (Flags & DWARFDebugMacro::HeaderFlagMask::MACRO_DEBUG_LINE_OFFSET) {
+          // Get offset to the line table from the cloned compile unit.
+          for (auto &V : getOutUnitDIE()->values()) {
+            if (V.getAttribute() == dwarf::DW_AT_stmt_list) {
+              StmtListOffset = V.getDIEInteger().getValue();
+              break;
+            }
+          }
+
+          if (!StmtListOffset) {
+            Flags &= ~DWARFDebugMacro::HeaderFlagMask::MACRO_DEBUG_LINE_OFFSET;
+            warn("couldn`t find line table for macro table.");
+          }
+        }
+
+        // Write flags.
+        OutSection.emitIntVal(Flags, sizeof(Flags));
+
+        // Write offset to line table.
+        if (StmtListOffset) {
+          OutSection.notePatch(DebugOffsetPatch{
+              OutSection.OS.tell(),
+              &getOrCreateSectionDescriptor(DebugSectionKind::DebugLine)});
+          // TODO: check that List.Header.getOffsetByteSize() and
+          // DebugOffsetPatch agree on size.
+          OutSection.emitIntVal(0xBADDEF, List.Header.getOffsetByteSize());
+        }
+      }
+
+      // Write macro entries.
+      for (const DWARFDebugMacro::Entry &MacroEntry : List.Macros) {
+        if (MacroEntry.Type == 0) {
+          encodeULEB128(MacroEntry.Type, OutSection.OS);
+          continue;
+        }
+
+        uint8_t MacroType = MacroEntry.Type;
+        switch (MacroType) {
+        default: {
+          bool HasVendorSpecificExtension =
+              (!hasDWARFv5Header &&
+               MacroType == dwarf::DW_MACINFO_vendor_ext) ||
+              (hasDWARFv5Header && (MacroType >= dwarf::DW_MACRO_lo_user &&
+                                    MacroType <= dwarf::DW_MACRO_hi_user));
+
+          if (HasVendorSpecificExtension) {
+            // Write macinfo type.
+            OutSection.emitIntVal(MacroType, 1);
+
+            // Write vendor extension constant.
+            encodeULEB128(MacroEntry.ExtConstant, OutSection.OS);
+
+            // Write vendor extension string.
+            OutSection.emitString(dwarf::DW_FORM_string, MacroEntry.ExtStr);
+          } else
+            warn("unknown macro type. skip.");
+        } break;
+        // debug_macro and debug_macinfo share some common encodings.
+        // DW_MACRO_define     == DW_MACINFO_define
+        // DW_MACRO_undef      == DW_MACINFO_undef
+        // DW_MACRO_start_file == DW_MACINFO_start_file
+        // DW_MACRO_end_file   == DW_MACINFO_end_file
+        // For readibility/uniformity we are using DW_MACRO_*.
+        case dwarf::DW_MACRO_define:
+        case dwarf::DW_MACRO_undef: {
+          // Write macinfo type.
+          OutSection.emitIntVal(MacroType, 1);
+
+          // Write source line.
+          encodeULEB128(MacroEntry.Line, OutSection.OS);
+
+          // Write macro string.
+          OutSection.emitString(dwarf::DW_FORM_string, MacroEntry.MacroStr);
+        } break;
+        case dwarf::DW_MACRO_define_strp:
+        case dwarf::DW_MACRO_undef_strp:
+        case dwarf::DW_MACRO_define_strx:
+        case dwarf::DW_MACRO_undef_strx: {
+          // DW_MACRO_*_strx forms are not supported currently.
+          // Convert to *_strp.
+          switch (MacroType) {
+          case dwarf::DW_MACRO_define_strx: {
+            MacroType = dwarf::DW_MACRO_define_strp;
+            if (!DefAttributeIsReported) {
+              warn("DW_MACRO_define_strx unsupported yet. Convert to "
+                   "DW_MACRO_define_strp.");
+              DefAttributeIsReported = true;
+            }
+          } break;
+          case dwarf::DW_MACRO_undef_strx: {
+            MacroType = dwarf::DW_MACRO_undef_strp;
+            if (!UndefAttributeIsReported) {
+              warn("DW_MACRO_undef_strx unsupported yet. Convert to "
+                   "DW_MACRO_undef_strp.");
+              UndefAttributeIsReported = true;
+            }
+          } break;
+          default:
+            // Nothing to do.
+            break;
+          }
+
+          // Write macinfo type.
+          OutSection.emitIntVal(MacroType, 1);
+
+          // Write source line.
+          encodeULEB128(MacroEntry.Line, OutSection.OS);
+
+          // Write macro string.
+          OutSection.emitString(dwarf::DW_FORM_strp, MacroEntry.MacroStr);
+          break;
+        }
+        case dwarf::DW_MACRO_start_file: {
+          // Write macinfo type.
+          OutSection.emitIntVal(MacroType, 1);
+          // Write source line.
+          encodeULEB128(MacroEntry.Line, OutSection.OS);
+          // Write source file id.
+          encodeULEB128(MacroEntry.File, OutSection.OS);
+        } break;
+        case dwarf::DW_MACRO_end_file: {
+          // Write macinfo type.
+          OutSection.emitIntVal(MacroType, 1);
+        } break;
+        case dwarf::DW_MACRO_import:
+        case dwarf::DW_MACRO_import_sup: {
+          if (!ImportAttributeIsReported) {
+            warn("DW_MACRO_import and DW_MACRO_import_sup are unsupported "
+                 "yet. remove.");
+            ImportAttributeIsReported = true;
+          }
+        } break;
+        }
+      }
+
+      return;
+    }
+  }
+}
+
+void CompileUnit::cloneDieAttrExpression(
+    const DWARFExpression &InputExpression,
+    SmallVectorImpl<uint8_t> &OutputExpression, SectionDescriptor &Section,
+    std::optional<int64_t> VarAddressAdjustment,
+    OffsetsPtrVector &PatchesOffsets) {
+  using Encoding = DWARFExpression::Operation::Encoding;
+
+  DWARFUnit &OrigUnit = getOrigUnit();
+  uint8_t OrigAddressByteSize = OrigUnit.getAddressByteSize();
+
+  uint64_t OpOffset = 0;
+  for (auto &Op : InputExpression) {
+    auto Desc = Op.getDescription();
+    // DW_OP_const_type is variable-length and has 3
+    // operands. Thus far we only support 2.
+    if ((Desc.Op.size() == 2 && Desc.Op[0] == Encoding::BaseTypeRef) ||
+        (Desc.Op.size() == 2 && Desc.Op[1] == Encoding::BaseTypeRef &&
+         Desc.Op[0] != Encoding::Size1))
+      warn("unsupported DW_OP encoding.");
+
+    if ((Desc.Op.size() == 1 && Desc.Op[0] == Encoding::BaseTypeRef) ||
+        (Desc.Op.size() == 2 && Desc.Op[1] == Encoding::BaseTypeRef &&
+         Desc.Op[0] == Encoding::Size1)) {
+      // This code assumes that the other non-typeref operand fits into 1 byte.
+      assert(OpOffset < Op.getEndOffset());
+      uint32_t ULEBsize = Op.getEndOffset() - OpOffset - 1;
+      assert(ULEBsize <= 16);
+
+      // Copy over the operation.
+      assert(!Op.getSubCode() && "SubOps not yet supported");
+      OutputExpression.push_back(Op.getCode());
+      uint64_t RefOffset;
+      if (Desc.Op.size() == 1) {
+        RefOffset = Op.getRawOperand(0);
+      } else {
+        OutputExpression.push_back(Op.getRawOperand(0));
+        RefOffset = Op.getRawOperand(1);
+      }
+      uint8_t ULEB[16];
+      uint32_t Offset = 0;
+      unsigned RealSize = 0;
+      // Look up the base type. For DW_OP_convert, the operand may be 0 to
+      // instead indicate the generic type. The same holds for
+      // DW_OP_reinterpret, which is currently not supported.
+      if (RefOffset > 0 || Op.getCode() != dwarf::DW_OP_convert) {
+        RefOffset += OrigUnit.getOffset();
+        uint32_t RefDieIdx = 0;
+        if (std::optional<uint32_t> Idx =
+                OrigUnit.getDIEIndexForOffset(RefOffset))
+          RefDieIdx = *Idx;
+
+        // Use fixed size for ULEB128 data, since we need to update that size
+        // later with the proper offsets. Use 5 for DWARF32, 9 for DWARF64.
+        ULEBsize = getFormParams().getDwarfOffsetByteSize() + 1;
+
+        RealSize = encodeULEB128(0xBADDEF, ULEB, ULEBsize);
+
+        Section.notePatchWithOffsetUpdate(
+            DebugULEB128DieRefPatch(OutputExpression.size(), this, this,
+                                    RefDieIdx),
+            PatchesOffsets);
+      } else
+        RealSize = encodeULEB128(Offset, ULEB, ULEBsize);
+
+      if (RealSize > ULEBsize) {
+        // Emit the generic type as a fallback.
+        RealSize = encodeULEB128(0, ULEB, ULEBsize);
+        warn("base type ref doesn't fit.");
+      }
+      assert(RealSize == ULEBsize && "padding failed");
+      ArrayRef<uint8_t> ULEBbytes(ULEB, ULEBsize);
+      OutputExpression.append(ULEBbytes.begin(), ULEBbytes.end());
+    } else if (!getGlobalData().getOptions().UpdateIndexTablesOnly &&
+               Op.getCode() == dwarf::DW_OP_addrx) {
+      if (std::optional<object::SectionedAddress> SA =
+              OrigUnit.getAddrOffsetSectionItem(Op.getRawOperand(0))) {
+        // DWARFLinker does not use addrx forms since it generates relocated
+        // addresses. Replace DW_OP_addrx with DW_OP_addr here.
+        // Argument of DW_OP_addrx should be relocated here as it is not
+        // processed by applyValidRelocs.
+        OutputExpression.push_back(dwarf::DW_OP_addr);
+        uint64_t LinkedAddress =
+            SA->Address + (VarAddressAdjustment ? *VarAddressAdjustment : 0);
+        if ((getEndianness() == support::endianness::little) !=
+            sys::IsLittleEndianHost)
+          sys::swapByteOrder(LinkedAddress);
+        ArrayRef<uint8_t> AddressBytes(
+            reinterpret_cast<const uint8_t *>(&LinkedAddress),
+            OrigAddressByteSize);
+        OutputExpression.append(AddressBytes.begin(), AddressBytes.end());
+      } else
+        warn("cann't read DW_OP_addrx operand.");
+    } else if (!getGlobalData().getOptions().UpdateIndexTablesOnly &&
+               Op.getCode() == dwarf::DW_OP_constx) {
+      if (std::optional<object::SectionedAddress> SA =
+              OrigUnit.getAddrOffsetSectionItem(Op.getRawOperand(0))) {
+        // DWARFLinker does not use constx forms since it generates relocated
+        // addresses. Replace DW_OP_constx with DW_OP_const[*]u here.
+        // Argument of DW_OP_constx should be relocated here as it is not
+        // processed by applyValidRelocs.
+        std::optional<uint8_t> OutOperandKind;
+        switch (OrigAddressByteSize) {
+        case 2:
+          OutOperandKind = dwarf::DW_OP_const2u;
+          break;
+        case 4:
+          OutOperandKind = dwarf::DW_OP_const4u;
+          break;
+        case 8:
+          OutOperandKind = dwarf::DW_OP_const8u;
+          break;
+        default:
+          warn(
+              formatv(("unsupported address size: {0}."), OrigAddressByteSize));
+          break;
+        }
+
+        if (OutOperandKind) {
+          OutputExpression.push_back(*OutOperandKind);
+          uint64_t LinkedAddress =
+              SA->Address + (VarAddressAdjustment ? *VarAddressAdjustment : 0);
+          if ((getEndianness() == support::endianness::little) !=
+              sys::IsLittleEndianHost)
+            sys::swapByteOrder(LinkedAddress);
+          ArrayRef<uint8_t> AddressBytes(
+              reinterpret_cast<const uint8_t *>(&LinkedAddress),
+              OrigAddressByteSize);
+          OutputExpression.append(AddressBytes.begin(), AddressBytes.end());
+        }
+      } else
+        warn("cann't read DW_OP_constx operand.");
+    } else {
+      // Copy over everything else unmodified.
+      StringRef Bytes =
+          InputExpression.getData().slice(OpOffset, Op.getEndOffset());
+      OutputExpression.append(Bytes.begin(), Bytes.end());
+    }
+    OpOffset = Op.getEndOffset();
+  }
+}
+
+Error CompileUnit::cloneAndEmit(std::optional<Triple> TargetTriple) {
+  BumpPtrAllocator Allocator;
+
+  DWARFDie OrigUnitDIE = getOrigUnit().getUnitDIE();
+  if (!OrigUnitDIE.isValid())
+    return Error::success();
+
+  CanStripTemplateName =
+      llvm::is_contained(getGlobalData().getOptions().AccelTables,
+                         DWARFLinker::AccelTableKind::Apple);
+
+  // Clone input DIE entry recursively.
+  DIE *OutCUDie =
+      cloneDIE(OrigUnitDIE.getDebugInfoEntry(), getDebugInfoHeaderSize(),
+               std::nullopt, std::nullopt, Allocator);
+  setOutUnitDIE(OutCUDie);
+
+  if (getGlobalData().getOptions().NoOutput || (OutCUDie == nullptr))
+    return Error::success();
+
+  assert(TargetTriple.has_value());
+  if (Error Err = cloneAndEmitLineTable(*TargetTriple))
+    return Err;
+
+  if (Error Err = cloneAndEmitDebugMacro())
+    return Err;
+
+  if (Error Err = emitDebugInfo(*TargetTriple))
+    return Err;
+
+  // ASSUMPTION: .debug_info section should already be emitted at this point.
+  // cloneAndEmitRanges & cloneAndEmitDebugLocations use .debug_info section
+  // data.
+
+  if (Error Err = cloneAndEmitRanges())
+    return Err;
+
+  if (Error Err = cloneAndEmitDebugLocations())
+    return Err;
+
+  if (Error Err = emitDebugAddrSection())
+    return Err;
+
+  if (Error Err = emitDebugStringOffsetSection())
+    return Err;
+
+  return emitAbbreviations();
+}
+
+bool needToClone(CompileUnit::DIEInfo &Info) {
+  return Info.getKeep() || Info.getKeepChildren();
+}
+
+DIE *CompileUnit::cloneDIE(const DWARFDebugInfoEntry *InputDieEntry,
+                           uint64_t OutOffset,
+                           std::optional<int64_t> FuncAddressAdjustment,
+                           std::optional<int64_t> VarAddressAdjustment,
+                           BumpPtrAllocator &Allocator) {
+  uint32_t InputDieIdx = getDIEIndex(InputDieEntry);
+  CompileUnit::DIEInfo &Info = getDIEInfo(InputDieIdx);
+
+  if (!needToClone(Info))
+    return nullptr;
+
+  bool HasLocationExpressionAddress = false;
+  if (InputDieEntry->getTag() == dwarf::DW_TAG_subprogram) {
+    // Get relocation adjustment value for the current function.
+    FuncAddressAdjustment =
+        getContaingFile().Addresses->getSubprogramRelocAdjustment(
+            getDIE(InputDieEntry));
+  } else if (InputDieEntry->getTag() == dwarf::DW_TAG_variable) {
+    // Get relocation adjustment value for the current variable.
+    std::pair<bool, std::optional<int64_t>> LocExprAddrAndRelocAdjustment =
+        getContaingFile().Addresses->getVariableRelocAdjustment(
+            getDIE(InputDieEntry));
+
+    HasLocationExpressionAddress = LocExprAddrAndRelocAdjustment.first;
+    if (LocExprAddrAndRelocAdjustment.first &&
+        LocExprAddrAndRelocAdjustment.second)
+      VarAddressAdjustment = *LocExprAddrAndRelocAdjustment.second;
+  }
+
+  DIEGenerator DIEGenerator(Allocator, *this);
+  DIE *ClonedDIE = DIEGenerator.createDIE(InputDieEntry->getTag(), OutOffset);
+  rememberDieOutOffset(InputDieIdx, OutOffset);
+
+  // Clone Attributes.
+  DIEAttributeCloner AttributesCloner(
+      ClonedDIE, *this, InputDieEntry, DIEGenerator, FuncAddressAdjustment,
+      VarAddressAdjustment, HasLocationExpressionAddress);
+  AttributesCloner.clone();
+
+  bool HasChildrenToClone = Info.getKeepChildren();
+  OutOffset = AttributesCloner.finalizeAbbreviations(HasChildrenToClone);
+
+  if (HasChildrenToClone) {
+    // Recursively clone children.
+    for (const DWARFDebugInfoEntry *CurChild =
+             getFirstChildEntry(InputDieEntry);
+         CurChild && CurChild->getAbbreviationDeclarationPtr();
+         CurChild = getSiblingEntry(CurChild)) {
+      if (DIE *ClonedChild =
+              cloneDIE(CurChild, OutOffset, FuncAddressAdjustment,
+                       VarAddressAdjustment, Allocator)) {
+        OutOffset = ClonedChild->getOffset() + ClonedChild->getSize();
+        DIEGenerator.addChild(ClonedChild);
+      }
+    }
+
+    // Account for the end of children marker.
+    OutOffset += sizeof(int8_t);
+  }
+
+  // Update our size.
+  ClonedDIE->setSize(OutOffset - ClonedDIE->getOffset());
+  return ClonedDIE;
+}
+
+Error CompileUnit::cloneAndEmitLineTable(Triple &TargetTriple) {
+  const DWARFDebugLine::LineTable *InputLineTable =
+      getContaingFile().Dwarf->getLineTableForUnit(&getOrigUnit());
+  if (InputLineTable == nullptr) {
+    warn("cann't load line table.");
+    return Error::success();
+  }
+
+  DWARFDebugLine::LineTable OutLineTable;
+
+  // Set Line Table header.
+  OutLineTable.Prologue = InputLineTable->Prologue;
+  OutLineTable.Prologue.FormParams.AddrSize = getFormParams().AddrSize;
+
+  // Set Line Table Rows.
+  if (getGlobalData().getOptions().UpdateIndexTablesOnly) {
+    OutLineTable.Rows = InputLineTable->Rows;
+    // If all the line table contains is a DW_LNE_end_sequence, clear the line
+    // table rows, it will be inserted again in the DWARFStreamer.
+    if (OutLineTable.Rows.size() == 1 && OutLineTable.Rows[0].EndSequence)
+      OutLineTable.Rows.clear();
+
+    OutLineTable.Sequences = InputLineTable->Sequences;
+  } else {
+    // This vector is the output line table.
+    std::vector<DWARFDebugLine::Row> NewRows;
+    NewRows.reserve(InputLineTable->Rows.size());
+
+    // Current sequence of rows being extracted, before being inserted
+    // in NewRows.
+    std::vector<DWARFDebugLine::Row> Seq;
+
+    const auto &FunctionRanges = getFunctionRanges();
+    std::optional<AddressRangeValuePair> CurrRange;
+
+    // FIXME: This logic is meant to generate exactly the same output as
+    // Darwin's classic dsymutil. There is a nicer way to implement this
+    // by simply putting all the relocated line info in NewRows and simply
+    // sorting NewRows before passing it to emitLineTableForUnit. This
+    // should be correct as sequences for a function should stay
+    // together in the sorted output. There are a few corner cases that
+    // look suspicious though, and that required to implement the logic
+    // this way. Revisit that once initial validation is finished.
+
+    // Iterate over the object file line info and extract the sequences
+    // that correspond to linked functions.
+    for (DWARFDebugLine::Row Row : InputLineTable->Rows) {
+      // Check whether we stepped out of the range. The range is
+      // half-open, but consider accept the end address of the range if
+      // it is marked as end_sequence in the input (because in that
+      // case, the relocation offset is accurate and that entry won't
+      // serve as the start of another function).
+      if (!CurrRange || !CurrRange->Range.contains(Row.Address.Address)) {
+        // We just stepped out of a known range. Insert a end_sequence
+        // corresponding to the end of the range.
+        uint64_t StopAddress =
+            CurrRange ? CurrRange->Range.end() + CurrRange->Value : -1ULL;
+        CurrRange = FunctionRanges.getRangeThatContains(Row.Address.Address);
+        if (StopAddress != -1ULL && !Seq.empty()) {
+          // Insert end sequence row with the computed end address, but
+          // the same line as the previous one.
+          auto NextLine = Seq.back();
+          NextLine.Address.Address = StopAddress;
+          NextLine.EndSequence = 1;
+          NextLine.PrologueEnd = 0;
+          NextLine.BasicBlock = 0;
+          NextLine.EpilogueBegin = 0;
+          Seq.push_back(NextLine);
+          insertLineSequence(Seq, NewRows);
+        }
+
+        if (!CurrRange)
+          continue;
+      }
+
+      // Ignore empty sequences.
+      if (Row.EndSequence && Seq.empty())
+        continue;
+
+      // Relocate row address and add it to the current sequence.
+      Row.Address.Address += CurrRange->Value;
+      Seq.emplace_back(Row);
+
+      if (Row.EndSequence)
+        insertLineSequence(Seq, NewRows);
+    }
+
+    OutLineTable.Rows = std::move(NewRows);
+  }
+
+  return emitDebugLine(TargetTriple, OutLineTable);
+}
+
+void CompileUnit::insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq,
+                                     std::vector<DWARFDebugLine::Row> &Rows) {
+  if (Seq.empty())
+    return;
+
+  if (!Rows.empty() && Rows.back().Address < Seq.front().Address) {
+    llvm::append_range(Rows, Seq);
+    Seq.clear();
+    return;
+  }
+
+  object::SectionedAddress Front = Seq.front().Address;
+  auto InsertPoint = partition_point(
+      Rows, [=](const DWARFDebugLine::Row &O) { return O.Address < Front; });
+
+  // FIXME: this only removes the unneeded end_sequence if the
+  // sequences have been inserted in order. Using a global sort like
+  // described in cloneAndEmitLineTable() and delaying the end_sequene
+  // elimination to DebugLineEmitter::emit() we can get rid of all of them.
+  if (InsertPoint != Rows.end() && InsertPoint->Address == Front &&
+      InsertPoint->EndSequence) {
+    *InsertPoint = Seq.front();
+    Rows.insert(InsertPoint + 1, Seq.begin() + 1, Seq.end());
+  } else {
+    Rows.insert(InsertPoint, Seq.begin(), Seq.end());
+  }
+
+  Seq.clear();
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+LLVM_DUMP_METHOD void CompileUnit::DIEInfo::dump() {
+  llvm::errs() << "{\n";
+  llvm::errs() << "  Placement: ";
+  switch (getPlacement()) {
+  case NotSet:
+    llvm::errs() << "NotSet\n";
+    break;
+  case TypeTable:
+    llvm::errs() << "TypeTable\n";
+    break;
+  case PlainDwarf:
+    llvm::errs() << "PlainDwarf\n";
+    break;
+  case Both:
+    llvm::errs() << "Both\n";
+    break;
+  case Parent:
+    llvm::errs() << "Parent\n";
+    break;
+  }
+
+  llvm::errs() << "  Keep: " << getKeep();
+  llvm::errs() << "  KeepChildren: " << getKeepChildren();
+  llvm::errs() << "  ReferrencedBy: " << getReferrencedBy();
+  llvm::errs() << "  IsInMouduleScope: " << getIsInMouduleScope();
+  llvm::errs() << "  IsInFunctionScope: " << getIsInFunctionScope();
+  llvm::errs() << "}\n";
+}
+#endif // if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.h b/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.h
index 1617a848512d5f..24cbcf4d6f1e2d 100644
--- a/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.h
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerCompileUnit.h
@@ -10,54 +10,334 @@
 #define LLVM_LIB_DWARFLINKERPARALLEL_DWARFLINKERCOMPILEUNIT_H
 
 #include "DWARFLinkerUnit.h"
+#include "IndexedValuesMap.h"
 #include "llvm/DWARFLinkerParallel/DWARFFile.h"
-#include "llvm/DWARFLinkerParallel/DWARFLinker.h"
 #include <optional>
 
 namespace llvm {
 namespace dwarflinker_parallel {
 
-struct LinkContext;
-class DWARFFile;
+using OffsetToUnitTy = function_ref<CompileUnit *(uint64_t Offset)>;
 
 /// Stores all information related to a compile unit, be it in its original
 /// instance of the object file or its brand new cloned and generated DIE tree.
 class CompileUnit : public DwarfUnit {
 public:
-  CompileUnit(LinkContext &, unsigned ID, StringRef ClangModuleName,
-              DWARFFile &File,
-              DWARFLinker::SwiftInterfacesMapTy *,
-              UnitMessageHandlerTy WarningHandler)
-      : DwarfUnit(ID, ClangModuleName, WarningHandler), ContaingFile(File) {
-    FormParams.Version = 4;
-    FormParams.Format = dwarf::DWARF32;
-    FormParams.AddrSize = 4;
-    UnitName = ContaingFile.FileName;
-  }
-
-  CompileUnit(LinkContext &, DWARFUnit &OrigUnit, unsigned ID,
+  /// The stages of new compile unit processing.
+  enum class Stage : uint8_t {
+    /// Created, linked with input DWARF file.
+    CreatedNotLoaded = 0,
+
+    /// Input DWARF is loaded.
+    Loaded,
+
+    /// Input DWARF is analysed(DIEs pointing to the real code section are
+    /// discovered, type names are assigned if ODR is requested).
+    LivenessAnalysisDone,
+
+    /// Output DWARF is generated.
+    Cloned,
+
+    /// Offsets inside patch records are updated.
+    PatchesUpdated,
+
+    /// Resources(Input DWARF, Output DWARF tree) are released.
+    Cleaned,
+  };
+
+  CompileUnit(LinkingGlobalData &GlobalData, unsigned ID,
+              StringRef ClangModuleName, DWARFFile &File,
+              OffsetToUnitTy UnitFromOffset)
+      : DwarfUnit(GlobalData, ID, ClangModuleName), File(File),
+        getUnitFromOffset(UnitFromOffset), Stage(Stage::CreatedNotLoaded) {
+    UnitName = File.FileName;
+  }
+
+  CompileUnit(LinkingGlobalData &GlobalData, DWARFUnit &OrigUnit, unsigned ID,
               StringRef ClangModuleName, DWARFFile &File,
-              UnitMessageHandlerTy WarningHandler)
-      : DwarfUnit(ID, ClangModuleName, WarningHandler),
-        ContaingFile(File), OrigUnit(&OrigUnit) {
+              OffsetToUnitTy UnitFromOffset)
+      : DwarfUnit(GlobalData, ID, ClangModuleName), File(File),
+        OrigUnit(&OrigUnit), getUnitFromOffset(UnitFromOffset),
+        Stage(Stage::CreatedNotLoaded) {
     DWARFDie CUDie = OrigUnit.getUnitDIE();
     if (!CUDie)
       return;
 
-    if (File.Dwarf)
-      Endianess = File.Dwarf->isLittleEndian() ? support::endianness::little
-                                               : support::endianness::big;
-
-    FormParams.Version = OrigUnit.getVersion();
-    FormParams.Format = dwarf::DWARF32;
-    FormParams.AddrSize = OrigUnit.getAddressByteSize();
+    setOutputFormat(OrigUnit);
 
     Language = dwarf::toUnsigned(CUDie.find(dwarf::DW_AT_language), 0);
-
-    UnitName = ContaingFile.FileName;
+    if (const char *CUName = CUDie.getName(DINameKind::ShortName))
+      UnitName = CUName;
+    else
+      UnitName = File.FileName;
     SysRoot = dwarf::toStringRef(CUDie.find(dwarf::DW_AT_LLVM_sysroot)).str();
   }
 
+  /// Returns stage of overall processing.
+  Stage getStage() const { return Stage; }
+
+  /// Set stage of overall processing.
+  void setStage(Stage Stage) { this->Stage = Stage; }
+
+  /// Loads unit line table.
+  void loadLineTable();
+
+  /// Returns name of the file for the \p FileIdx
+  /// from the unit`s line table.
+  StringEntry *getFileName(unsigned FileIdx, StringPool &GlobalStrings);
+
+  /// Returns DWARFFile containing this compile unit.
+  const DWARFFile &getContaingFile() const { return File; }
+
+  /// Load DIEs of input compilation unit. \returns true if input DIEs
+  /// successfully loaded.
+  bool loadInputDIEs();
+
+  /// Reset compile units data(results of liveness analysis, clonning)
+  /// if current stage greater than Stage::Loaded. We need to reset data
+  /// as we are going to repeat stages.
+  void maybeResetToLoadedStage();
+
+  /// Collect references to parseable Swift interfaces in imported
+  /// DW_TAG_module blocks.
+  void analyzeImportedModule(const DWARFDebugInfoEntry *DieEntry);
+
+  /// Navigate DWARF tree and set die properties.
+  void analyzeDWARFStructure() {
+    analyzeDWARFStructureRec(getUnitDIE().getDebugInfoEntry(), false, false);
+  }
+
+  /// Cleanup unneeded resources after compile unit is cloned.
+  void cleanupDataAfterClonning();
+
+  /// After cloning stage the output DIEs offsets are deallocated.
+  /// This method copies output offsets for referenced DIEs into DIEs patches.
+  void updateDieRefPatchesWithClonedOffsets();
+
+  /// Kinds of placement for the output die.
+  enum DieOutputPlacement : uint8_t {
+    NotSet = 0,
+
+    /// Corresponding DIE goes to the type table only.
+    /// NOTE: Not used yet.
+    TypeTable = 1,
+
+    /// Corresponding DIE goes to the plain dwarf only.
+    PlainDwarf = 2,
+
+    /// Corresponding DIE goes to type table and to plain dwarf.
+    /// NOTE: Not used yet.
+    Both = 3,
+
+    /// Corresponding DIE needs to examine parent to determine
+    /// the point of placement.
+    /// NOTE: Not used yet.
+    Parent = 4
+  };
+
+  /// Information gathered about source DIEs.
+  struct DIEInfo {
+    DIEInfo() = default;
+    DIEInfo(const DIEInfo &Other) { Flags = Other.Flags.load(); }
+    DIEInfo &operator=(const DIEInfo &Other) {
+      Flags = Other.Flags.load();
+      return *this;
+    }
+
+    /// Data member keeping various flags.
+    std::atomic<uint16_t> Flags = {0};
+
+    /// \returns Placement kind for the corresponding die.
+    DieOutputPlacement getPlacement() const {
+      return DieOutputPlacement(Flags & 0x7);
+    }
+
+    /// Sets Placement kind for the corresponding die.
+    void setPlacement(DieOutputPlacement Placement) {
+      auto InputData = Flags.load();
+      while (!Flags.compare_exchange_weak(InputData,
+                                          ((InputData & ~0x7) | Placement))) {
+      }
+    }
+
+    /// Unsets Placement kind for the corresponding die.
+    void unsetPlacement() {
+      auto InputData = Flags.load();
+      while (!Flags.compare_exchange_weak(InputData, (InputData & ~0x7))) {
+      }
+    }
+
+    /// Sets Placement kind for the corresponding die.
+    bool setPlacementIfUnset(DieOutputPlacement Placement) {
+      auto InputData = Flags.load();
+      if ((InputData & 0x7) == NotSet)
+        if (Flags.compare_exchange_weak(InputData, (InputData | Placement)))
+          return true;
+
+      return false;
+    }
+
+#define SINGLE_FLAG_METHODS_SET(Name, Value)                                   \
+  bool get##Name() const { return Flags & Value; }                             \
+  void set##Name() {                                                           \
+    auto InputData = Flags.load();                                             \
+    while (!Flags.compare_exchange_weak(InputData, InputData | Value)) {       \
+    }                                                                          \
+  }                                                                            \
+  void unset##Name() {                                                         \
+    auto InputData = Flags.load();                                             \
+    while (!Flags.compare_exchange_weak(InputData, InputData & ~Value)) {      \
+    }                                                                          \
+  }
+
+    /// DIE is a part of the linked output.
+    SINGLE_FLAG_METHODS_SET(Keep, 0x08)
+
+    /// DIE has children which are part of the linked output.
+    SINGLE_FLAG_METHODS_SET(KeepChildren, 0x10)
+
+    /// DIE is referenced by other DIE.
+    SINGLE_FLAG_METHODS_SET(ReferrencedBy, 0x20)
+
+    /// DIE is in module scope.
+    SINGLE_FLAG_METHODS_SET(IsInMouduleScope, 0x40)
+
+    /// DIE is in function scope.
+    SINGLE_FLAG_METHODS_SET(IsInFunctionScope, 0x80)
+
+    void unsetFlagsWhichSetDuringLiveAnalysis() {
+      auto InputData = Flags.load();
+      while (!Flags.compare_exchange_weak(
+          InputData, InputData & ~(0x7 | 0x8 | 0x10 | 0x20))) {
+      }
+    }
+
+    /// Erase all flags.
+    void eraseData() { Flags = 0; }
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+    LLVM_DUMP_METHOD void dump();
+#endif
+  };
+
+  /// \defgroup Group of functions returning DIE info.
+  ///
+  /// @{
+
+  /// \p Idx index of the DIE.
+  /// \returns DieInfo descriptor.
+  DIEInfo &getDIEInfo(unsigned Idx) { return DieInfoArray[Idx]; }
+
+  /// \p Idx index of the DIE.
+  /// \returns DieInfo descriptor.
+  const DIEInfo &getDIEInfo(unsigned Idx) const { return DieInfoArray[Idx]; }
+
+  /// \p Idx index of the DIE.
+  /// \returns DieInfo descriptor.
+  DIEInfo &getDIEInfo(const DWARFDebugInfoEntry *Entry) {
+    return DieInfoArray[getOrigUnit().getDIEIndex(Entry)];
+  }
+
+  /// \p Idx index of the DIE.
+  /// \returns DieInfo descriptor.
+  const DIEInfo &getDIEInfo(const DWARFDebugInfoEntry *Entry) const {
+    return DieInfoArray[getOrigUnit().getDIEIndex(Entry)];
+  }
+
+  /// \p Die
+  /// \returns PlainDieInfo descriptor.
+  DIEInfo &getDIEInfo(const DWARFDie &Die) {
+    return DieInfoArray[getOrigUnit().getDIEIndex(Die)];
+  }
+
+  /// \p Die
+  /// \returns PlainDieInfo descriptor.
+  const DIEInfo &getDIEInfo(const DWARFDie &Die) const {
+    return DieInfoArray[getOrigUnit().getDIEIndex(Die)];
+  }
+
+  /// \p Idx index of the DIE.
+  /// \returns DieInfo descriptor.
+  uint64_t getDieOutOffset(uint32_t Idx) {
+    return reinterpret_cast<std::atomic<uint64_t> *>(&OutDieOffsetArray[Idx])
+        ->load();
+  }
+
+  /// \p Idx index of the DIE.
+  /// \returns DieInfo descriptor.
+  void rememberDieOutOffset(uint32_t Idx, uint64_t Offset) {
+    reinterpret_cast<std::atomic<uint64_t> *>(&OutDieOffsetArray[Idx])
+        ->store(Offset);
+  }
+
+  /// @}
+
+  /// Returns value of DW_AT_low_pc attribute.
+  std::optional<uint64_t> getLowPc() const { return LowPc; }
+
+  /// Returns value of DW_AT_high_pc attribute.
+  uint64_t getHighPc() const { return HighPc; }
+
+  /// Returns true if there is a label corresponding to the specified \p Addr.
+  bool hasLabelAt(uint64_t Addr) const { return Labels.count(Addr); }
+
+  /// Add the low_pc of a label that is relocated by applying
+  /// offset \p PCOffset.
+  void addLabelLowPc(uint64_t LabelLowPc, int64_t PcOffset);
+
+  /// Resolve the DIE attribute reference that has been extracted in \p
+  /// RefValue. The resulting DIE might be in another CompileUnit.
+  /// \returns referenced die and corresponding compilation unit.
+  ///          compilation unit is null if reference could not be resolved.
+  std::optional<std::pair<CompileUnit *, uint32_t>>
+  resolveDIEReference(const DWARFFormValue &RefValue);
+  /// @}
+
+  /// Add a function range [\p LowPC, \p HighPC) that is relocated by applying
+  /// offset \p PCOffset.
+  void addFunctionRange(uint64_t LowPC, uint64_t HighPC, int64_t PCOffset);
+
+  /// Returns function ranges of this unit.
+  const RangesTy &getFunctionRanges() const { return Ranges; }
+
+  /// Clone and emit this compilation unit.
+  Error cloneAndEmit(std::optional<Triple> TargetTriple);
+
+  /// Clone and emit debug locations(.debug_loc/.debug_loclists).
+  Error cloneAndEmitDebugLocations();
+
+  /// Clone and emit ranges.
+  Error cloneAndEmitRanges();
+
+  /// Clone and emit debug macros(.debug_macinfo/.debug_macro).
+  Error cloneAndEmitDebugMacro();
+
+  // Clone input DIE entry.
+  DIE *cloneDIE(const DWARFDebugInfoEntry *InputDieEntry, uint64_t OutOffset,
+                std::optional<int64_t> FuncAddressAdjustment,
+                std::optional<int64_t> VarAddressAdjustment,
+                BumpPtrAllocator &Allocator);
+
+  // Clone and emit line table.
+  Error cloneAndEmitLineTable(Triple &TargetTriple);
+
+  /// Clone attribute location axpression.
+  void cloneDieAttrExpression(const DWARFExpression &InputExpression,
+                              SmallVectorImpl<uint8_t> &OutputExpression,
+                              SectionDescriptor &Section,
+                              std::optional<int64_t> VarAddressAdjustment,
+                              OffsetsPtrVector &PatchesOffsets);
+
+  /// Returns index(inside .debug_addr) of an address.
+  uint64_t getDebugAddrIndex(uint64_t Addr) {
+    return DebugAddrIndexMap.getValueIndex(Addr);
+  }
+
+  /// Returns index(inside .debug_str_offsets) of specified string.
+  uint64_t getDebugStrIndex(const StringEntry *String) {
+    return DebugStringIndexMap.getValueIndex(String);
+  }
+
   /// \defgroup Helper methods to access OrigUnit.
   ///
   /// @{
@@ -142,12 +422,144 @@ class CompileUnit : public DwarfUnit {
 
   /// @}
 
+  /// \defgroup Methods used for reporting warnings and errors:
+  ///
+  /// @{
+
+  void warn(const Twine &Warning, const DWARFDie *DIE = nullptr) {
+    GlobalData.warn(Warning, getUnitName(), DIE);
+  }
+
+  void warn(Error Warning, const DWARFDie *DIE = nullptr) {
+    handleAllErrors(std::move(Warning), [&](ErrorInfoBase &Info) {
+      GlobalData.warn(Info.message(), getUnitName(), DIE);
+    });
+  }
+
+  void warn(const Twine &Warning, const DWARFDebugInfoEntry *DieEntry) {
+    if (DieEntry != nullptr) {
+      DWARFDie DIE(&getOrigUnit(), DieEntry);
+      GlobalData.warn(Warning, getUnitName(), &DIE);
+      return;
+    }
+
+    GlobalData.warn(Warning, getUnitName());
+  }
+
+  void error(const Twine &Err, const DWARFDie *DIE = nullptr) {
+    GlobalData.warn(Err, getUnitName(), DIE);
+  }
+
+  void error(Error Err, const DWARFDie *DIE = nullptr) {
+    handleAllErrors(std::move(Err), [&](ErrorInfoBase &Info) {
+      GlobalData.error(Info.message(), getUnitName(), DIE);
+    });
+  }
+
+  /// @}
+
 private:
+  /// Navigate DWARF tree recursively and set die properties.
+  void analyzeDWARFStructureRec(const DWARFDebugInfoEntry *DieEntry,
+                                bool IsInModule, bool IsInFunction);
+
+  struct LinkedLocationExpressionsWithOffsetPatches {
+    DWARFLocationExpression Expression;
+    OffsetsPtrVector Patches;
+  };
+  using LinkedLocationExpressionsVector =
+      SmallVector<LinkedLocationExpressionsWithOffsetPatches>;
+
+  /// Emit debug locations.
+  void emitLocations(DebugSectionKind LocationSectionKind);
+
+  /// Emit location list header.
+  uint64_t emitLocListHeader(SectionDescriptor &OutLocationSection);
+
+  /// Emit location list fragment.
+  uint64_t emitLocListFragment(
+      const LinkedLocationExpressionsVector &LinkedLocationExpression,
+      SectionDescriptor &OutLocationSection);
+
+  /// Emit the .debug_addr section fragment for current unit.
+  Error emitDebugAddrSection();
+
+  /// Emit the .debug_str_offsets section for current unit.
+  Error emitDebugStringOffsetSection();
+
+  /// Emit .debug_aranges.
+  void emitAranges(AddressRanges &LinkedFunctionRanges);
+
+  /// Clone and emit .debug_ranges/.debug_rnglists.
+  void cloneAndEmitRangeList(DebugSectionKind RngSectionKind,
+                             AddressRanges &LinkedFunctionRanges);
+
+  /// Emit range list header.
+  uint64_t emitRangeListHeader(SectionDescriptor &OutRangeSection);
+
+  /// Emit range list fragment.
+  void emitRangeListFragment(const AddressRanges &LinkedRanges,
+                             SectionDescriptor &OutRangeSection);
+
+  /// Insert the new line info sequence \p Seq into the current
+  /// set of already linked line info \p Rows.
+  void insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq,
+                          std::vector<DWARFDebugLine::Row> &Rows);
+
+  /// Emits body for both macro sections.
+  void emitMacroTableImpl(const DWARFDebugMacro *MacroTable,
+                          uint64_t OffsetToMacroTable, bool hasDWARFv5Header);
+
   /// DWARFFile containing this compile unit.
-  DWARFFile &ContaingFile;
+  DWARFFile &File;
 
   /// Pointer to the paired compile unit from the input DWARF.
   DWARFUnit *OrigUnit = nullptr;
+
+  /// Line table for this unit.
+  const DWARFDebugLine::LineTable *LineTablePtr = nullptr;
+
+  /// Cached resolved paths from the line table.
+  /// The key is <UniqueUnitID, FileIdx>.
+  using ResolvedPathsMap = DenseMap<unsigned, StringEntry *>;
+  ResolvedPathsMap ResolvedFullPaths;
+  StringMap<StringEntry *> ResolvedParentPaths;
+
+  /// This field instructs compile unit to store DIE name with stripped
+  /// template parameters into the accelerator table.
+  bool CanStripTemplateName = false;
+
+  /// Maps an address into the index inside .debug_addr section.
+  IndexedValuesMap<uint64_t> DebugAddrIndexMap;
+
+  /// Maps a string into the index inside .debug_str_offsets section.
+  IndexedValuesMap<const StringEntry *> DebugStringIndexMap;
+
+  /// \defgroup Data Members accessed asinchroniously.
+  ///
+  /// @{
+  OffsetToUnitTy getUnitFromOffset;
+
+  std::optional<uint64_t> LowPc;
+  uint64_t HighPc = 0;
+
+  /// The ranges in that map are the PC ranges for functions in this unit,
+  /// associated with the PC offset to apply to the addresses to get
+  /// the linked address.
+  RangesTy Ranges;
+  std::mutex RangesMutex;
+
+  /// The DW_AT_low_pc of each DW_TAG_label.
+  SmallDenseMap<uint64_t, uint64_t, 1> Labels;
+  std::mutex LabelsMutex;
+
+  /// This field keeps current stage of overall compile unit processing.
+  std::atomic<Stage> Stage;
+
+  /// DIE info indexed by DIE index.
+  SmallVector<DIEInfo> DieInfoArray;
+  SmallVector<uint64_t> OutDieOffsetArray;
+  /// @}
 };
 
 } // end of namespace dwarflinker_parallel

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerGlobalData.h b/llvm/lib/DWARFLinkerParallel/DWARFLinkerGlobalData.h
new file mode 100644
index 00000000000000..78d0b5468d0495
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerGlobalData.h
@@ -0,0 +1,159 @@
+//===- DWARFLinkerGlobalData.h ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_DWARFLINKERGLOBALDATA_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_DWARFLINKERGLOBALDATA_H
+
+#include "llvm/DWARFLinkerParallel/DWARFLinker.h"
+#include "llvm/DWARFLinkerParallel/StringPool.h"
+#include "llvm/Support/PerThreadBumpPtrAllocator.h"
+#include <map>
+
+namespace llvm {
+
+class DWARFDie;
+
+namespace dwarflinker_parallel {
+
+using TranslatorFuncTy = std::function<StringRef(StringRef)>;
+using MessageHandlerTy = std::function<void(
+    const Twine &Warning, StringRef Context, const DWARFDie *DIE)>;
+
+/// linking options
+struct DWARFLinkerOptions {
+  /// DWARF version for the output.
+  uint16_t TargetDWARFVersion = 0;
+
+  /// Generate processing log to the standard output.
+  bool Verbose = false;
+
+  /// Print statistics.
+  bool Statistics = false;
+
+  /// Verify the input DWARF.
+  bool VerifyInputDWARF = false;
+
+  /// Do not emit output.
+  bool NoOutput = false;
+
+  /// Do not unique types according to ODR
+  bool NoODR = false;
+
+  /// Update index tables.
+  bool UpdateIndexTablesOnly = false;
+
+  /// Whether we want a static variable to force us to keep its enclosing
+  /// function.
+  bool KeepFunctionForStatic = false;
+
+  /// Allow to generate valid, but non deterministic output.
+  bool AllowNonDeterministicOutput = false;
+
+  /// Number of threads.
+  unsigned Threads = 1;
+
+  /// The accelerator table kinds
+  SmallVector<DWARFLinker::AccelTableKind, 1> AccelTables;
+
+  /// Prepend path for the clang modules.
+  std::string PrependPath;
+
+  /// input verification handler(it might be called asynchronously).
+  DWARFLinker::InputVerificationHandlerTy InputVerificationHandler = nullptr;
+
+  /// A list of all .swiftinterface files referenced by the debug
+  /// info, mapping Module name to path on disk. The entries need to
+  /// be uniqued and sorted and there are only few entries expected
+  /// per compile unit, which is why this is a std::map.
+  /// this is dsymutil specific fag.
+  ///
+  /// (it might be called asynchronously).
+  DWARFLinker::SwiftInterfacesMapTy *ParseableSwiftInterfaces = nullptr;
+
+  /// A list of remappings to apply to file paths.
+  ///
+  /// (it might be called asynchronously).
+  DWARFLinker::ObjectPrefixMapTy *ObjectPrefixMap = nullptr;
+};
+
+class DWARFLinkerImpl;
+
+/// This class keeps data and services common for the whole linking process.
+class LinkingGlobalData {
+  friend DWARFLinkerImpl;
+
+public:
+  /// Returns global per-thread allocator.
+  parallel::PerThreadBumpPtrAllocator &getAllocator() { return Allocator; }
+
+  /// Returns global string pool.
+  StringPool &getStringPool() { return Strings; }
+
+  /// Set translation function.
+  void setTranslator(TranslatorFuncTy Translator) {
+    this->Translator = Translator;
+  }
+
+  /// Translate specified string.
+  StringRef translateString(StringRef String) {
+    if (Translator)
+      return Translator(String);
+
+    return String;
+  }
+
+  /// Returns linking options.
+  const DWARFLinkerOptions &getOptions() const { return Options; }
+
+  /// Set warning handler.
+  void setWarningHandler(MessageHandlerTy Handler) { WarningHandler = Handler; }
+
+  /// Set error handler.
+  void setErrorHandler(MessageHandlerTy Handler) { ErrorHandler = Handler; }
+
+  /// Report warning.
+  void warn(const Twine &Warning, StringRef Context,
+            const DWARFDie *DIE = nullptr) {
+    if (WarningHandler)
+      (WarningHandler)(Warning, Context, DIE);
+  }
+
+  /// Report warning.
+  void warn(Error Warning, StringRef Context, const DWARFDie *DIE = nullptr) {
+    handleAllErrors(std::move(Warning), [&](ErrorInfoBase &Info) {
+      warn(Info.message(), Context, DIE);
+    });
+  }
+
+  /// Report error.
+  void error(const Twine &Err, StringRef Context,
+             const DWARFDie *DIE = nullptr) {
+    if (ErrorHandler)
+      (ErrorHandler)(Err, Context, DIE);
+  }
+
+  /// Report error.
+  void error(Error Err, StringRef Context, const DWARFDie *DIE = nullptr) {
+    handleAllErrors(std::move(Err), [&](ErrorInfoBase &Info) {
+      error(Info.message(), Context, DIE);
+    });
+  }
+
+protected:
+  parallel::PerThreadBumpPtrAllocator Allocator;
+  StringPool Strings;
+  TranslatorFuncTy Translator;
+  DWARFLinkerOptions Options;
+  MessageHandlerTy WarningHandler;
+  MessageHandlerTy ErrorHandler;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_DWARFLINKERGLOBALDATA_H

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.cpp b/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.cpp
index dfd77af92f2727..04d8024bcd7635 100644
--- a/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.cpp
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.cpp
@@ -7,33 +7,20 @@
 //===----------------------------------------------------------------------===//
 
 #include "DWARFLinkerImpl.h"
+#include "DIEGenerator.h"
+#include "DependencyTracker.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/Parallel.h"
+#include "llvm/Support/ThreadPool.h"
 
 namespace llvm {
 namespace dwarflinker_parallel {
 
-/// Similar to DWARFUnitSection::getUnitForOffset(), but returning our
-/// CompileUnit object instead.
-CompileUnit *
-DWARFLinkerImpl::LinkContext::getUnitForOffset(CompileUnit &CurrentCU,
-                                               uint64_t Offset) const {
-  if (CurrentCU.isClangModule())
-    return &CurrentCU;
-
-  auto CU = llvm::upper_bound(
-      CompileUnits, Offset,
-      [](uint64_t LHS, const std::unique_ptr<CompileUnit> &RHS) {
-        return LHS < RHS->getOrigUnit().getNextUnitOffset();
-      });
-
-  return CU != CompileUnits.end() ? CU->get() : nullptr;
-}
-
 Error DWARFLinkerImpl::createEmitter(const Triple &TheTriple,
                                      OutputFileType FileType,
                                      raw_pwrite_stream &OutFile) {
 
-  TheDwarfEmitter = std::make_unique<DwarfEmitterImpl>(
-      FileType, OutFile, OutputStrings.getTranslator(), WarningHandler);
+  TheDwarfEmitter = std::make_unique<DwarfEmitterImpl>(FileType, OutFile);
 
   return TheDwarfEmitter->init(TheTriple, "__DWARF");
 }
@@ -42,5 +29,1058 @@ ExtraDwarfEmitter *DWARFLinkerImpl::getEmitter() {
   return TheDwarfEmitter.get();
 }
 
+void DWARFLinkerImpl::addObjectFile(DWARFFile &File, ObjFileLoaderTy Loader,
+                                    CompileUnitHandlerTy OnCUDieLoaded) {
+  ObjectContexts.emplace_back(std::make_unique<LinkContext>(
+      GlobalData, File, ClangModules, UniqueUnitID,
+      (TheDwarfEmitter.get() == nullptr ? std::optional<Triple>(std::nullopt)
+                                        : TheDwarfEmitter->getTargetTriple())));
+
+  if (ObjectContexts.back()->InputDWARFFile.Dwarf) {
+    for (const std::unique_ptr<DWARFUnit> &CU :
+         ObjectContexts.back()->InputDWARFFile.Dwarf->compile_units()) {
+      DWARFDie CUDie = CU->getUnitDIE();
+      OverallNumberOfCU++;
+
+      if (!CUDie)
+        continue;
+
+      OnCUDieLoaded(*CU);
+
+      // Register mofule reference.
+      if (!GlobalData.getOptions().UpdateIndexTablesOnly)
+        ObjectContexts.back()->registerModuleReference(CUDie, Loader,
+                                                       OnCUDieLoaded);
+    }
+  }
+}
+
+Error DWARFLinkerImpl::link() {
+  // reset compile unit unique ID counter.
+  UniqueUnitID = 0;
+
+  if (Error Err = validateAndUpdateOptions())
+    return Err;
+
+  std::optional<dwarf::FormParams> Format;
+  std::optional<support::endianness> Endianess;
+
+  for (std::unique_ptr<LinkContext> &Context : ObjectContexts) {
+    if (Context->InputDWARFFile.Dwarf.get() == nullptr)
+      continue;
+
+    if (GlobalData.getOptions().Verbose) {
+      outs() << "OBJECT: " << Context->InputDWARFFile.FileName << "\n";
+
+      for (const std::unique_ptr<DWARFUnit> &OrigCU :
+           Context->InputDWARFFile.Dwarf->compile_units()) {
+        outs() << "Input compilation unit:";
+        DIDumpOptions DumpOpts;
+        DumpOpts.ChildRecurseDepth = 0;
+        DumpOpts.Verbose = GlobalData.getOptions().Verbose;
+        OrigCU->getUnitDIE().dump(outs(), 0, DumpOpts);
+      }
+    }
+
+    // Verify input DWARF if requested.
+    if (GlobalData.getOptions().VerifyInputDWARF)
+      verifyInput(Context->InputDWARFFile);
+
+    for (const std::unique_ptr<DWARFUnit> &OrigCU :
+         Context->InputDWARFFile.Dwarf->compile_units()) {
+      if (!Format)
+        Format = OrigCU.get()->getFormParams();
+    }
+
+    if (!Endianess)
+      Endianess = Context->InputDWARFFile.Dwarf->isLittleEndian()
+                      ? support::endianness::little
+                      : support::endianness::big;
+  }
+
+  if (!Format)
+    Format = {GlobalData.getOptions().TargetDWARFVersion, 8,
+              dwarf::DwarfFormat::DWARF32};
+  Format->Version = GlobalData.getOptions().TargetDWARFVersion;
+  if (!Endianess)
+    Endianess = support::endianness::little;
+
+  CommonSections.setOutputFormat(*Format, *Endianess);
+
+  // Set parallel options.
+  if (GlobalData.getOptions().Threads == 0)
+    parallel::strategy = optimal_concurrency(OverallNumberOfCU);
+  else
+    parallel::strategy = hardware_concurrency(GlobalData.getOptions().Threads);
+
+  // Link object files.
+  if (GlobalData.getOptions().Threads == 1) {
+    for (std::unique_ptr<LinkContext> &Context : ObjectContexts) {
+      // Link object file.
+      if (Error Err = Context->link())
+        GlobalData.error(std::move(Err), Context->InputDWARFFile.FileName);
+
+      Context->InputDWARFFile.unload();
+    }
+  } else {
+    ThreadPool Pool(parallel::strategy);
+    for (std::unique_ptr<LinkContext> &Context : ObjectContexts)
+      Pool.async([&]() {
+        // Link object file.
+        if (Error Err = Context->link())
+          GlobalData.error(std::move(Err), Context->InputDWARFFile.FileName);
+
+        Context->InputDWARFFile.unload();
+      });
+
+    Pool.wait();
+  }
+
+  // At this stage each compile units are cloned to their own set of debug
+  // sections. Now, update patches, assign offsets and assemble final file
+  // glueing debug tables from each compile unit.
+  glueCompileUnitsAndWriteToTheOutput();
+
+  return Error::success();
+}
+
+void DWARFLinkerImpl::verifyInput(const DWARFFile &File) {
+  assert(File.Dwarf);
+
+  raw_ostream &os = GlobalData.getOptions().Verbose ? errs() : nulls();
+  DIDumpOptions DumpOpts;
+  if (!File.Dwarf->verify(os, DumpOpts.noImplicitRecursion())) {
+    if (GlobalData.getOptions().InputVerificationHandler)
+      GlobalData.getOptions().InputVerificationHandler(File);
+  }
+}
+
+Error DWARFLinkerImpl::validateAndUpdateOptions() {
+  if (GlobalData.getOptions().TargetDWARFVersion == 0)
+    return createStringError(std::errc::invalid_argument,
+                             "target DWARF version is not set");
+
+  GlobalData.Options.NoOutput = TheDwarfEmitter.get() == nullptr;
+
+  if (GlobalData.getOptions().Verbose && GlobalData.getOptions().Threads != 1) {
+    GlobalData.Options.Threads = 1;
+    GlobalData.warn(
+        "set number of threads to 1 to make --verbose to work properly.", "");
+  }
+
+  return Error::success();
+}
+
+/// Resolve the relative path to a build artifact referenced by DWARF by
+/// applying DW_AT_comp_dir.
+static void resolveRelativeObjectPath(SmallVectorImpl<char> &Buf, DWARFDie CU) {
+  sys::path::append(Buf, dwarf::toString(CU.find(dwarf::DW_AT_comp_dir), ""));
+}
+
+static uint64_t getDwoId(const DWARFDie &CUDie) {
+  auto DwoId = dwarf::toUnsigned(
+      CUDie.find({dwarf::DW_AT_dwo_id, dwarf::DW_AT_GNU_dwo_id}));
+  if (DwoId)
+    return *DwoId;
+  return 0;
+}
+
+static std::string
+remapPath(StringRef Path,
+          const DWARFLinker::ObjectPrefixMapTy &ObjectPrefixMap) {
+  if (ObjectPrefixMap.empty())
+    return Path.str();
+
+  SmallString<256> p = Path;
+  for (const auto &Entry : ObjectPrefixMap)
+    if (llvm::sys::path::replace_path_prefix(p, Entry.first, Entry.second))
+      break;
+  return p.str().str();
+}
+
+static std::string getPCMFile(const DWARFDie &CUDie,
+                              DWARFLinker::ObjectPrefixMapTy *ObjectPrefixMap) {
+  std::string PCMFile = dwarf::toString(
+      CUDie.find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), "");
+
+  if (PCMFile.empty())
+    return PCMFile;
+
+  if (ObjectPrefixMap)
+    PCMFile = remapPath(PCMFile, *ObjectPrefixMap);
+
+  return PCMFile;
+}
+
+std::pair<bool, bool> DWARFLinkerImpl::LinkContext::isClangModuleRef(
+    const DWARFDie &CUDie, std::string &PCMFile, unsigned Indent, bool Quiet) {
+  if (PCMFile.empty())
+    return std::make_pair(false, false);
+
+  // Clang module DWARF skeleton CUs abuse this for the path to the module.
+  uint64_t DwoId = getDwoId(CUDie);
+
+  std::string Name = dwarf::toString(CUDie.find(dwarf::DW_AT_name), "");
+  if (Name.empty()) {
+    if (!Quiet)
+      GlobalData.warn("anonymous module skeleton CU for " + PCMFile + ".",
+                      InputDWARFFile.FileName);
+    return std::make_pair(true, true);
+  }
+
+  if (!Quiet && GlobalData.getOptions().Verbose) {
+    outs().indent(Indent);
+    outs() << "Found clang module reference " << PCMFile;
+  }
+
+  auto Cached = ClangModules.find(PCMFile);
+  if (Cached != ClangModules.end()) {
+    // FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is
+    // fixed in clang, only warn about DWO_id mismatches in verbose mode.
+    // ASTFileSignatures will change randomly when a module is rebuilt.
+    if (!Quiet && GlobalData.getOptions().Verbose && (Cached->second != DwoId))
+      GlobalData.warn(
+          Twine("hash mismatch: this object file was built against a "
+                "
diff erent version of the module ") +
+              PCMFile + ".",
+          InputDWARFFile.FileName);
+    if (!Quiet && GlobalData.getOptions().Verbose)
+      outs() << " [cached].\n";
+    return std::make_pair(true, true);
+  }
+
+  return std::make_pair(true, false);
+}
+
+/// If this compile unit is really a skeleton CU that points to a
+/// clang module, register it in ClangModules and return true.
+///
+/// A skeleton CU is a CU without children, a DW_AT_gnu_dwo_name
+/// pointing to the module, and a DW_AT_gnu_dwo_id with the module
+/// hash.
+bool DWARFLinkerImpl::LinkContext::registerModuleReference(
+    const DWARFDie &CUDie, ObjFileLoaderTy Loader,
+    CompileUnitHandlerTy OnCUDieLoaded, unsigned Indent) {
+  std::string PCMFile =
+      getPCMFile(CUDie, GlobalData.getOptions().ObjectPrefixMap);
+  std::pair<bool, bool> IsClangModuleRef =
+      isClangModuleRef(CUDie, PCMFile, Indent, false);
+
+  if (!IsClangModuleRef.first)
+    return false;
+
+  if (IsClangModuleRef.second)
+    return true;
+
+  if (GlobalData.getOptions().Verbose)
+    outs() << " ...\n";
+
+  // Cyclic dependencies are disallowed by Clang, but we still
+  // shouldn't run into an infinite loop, so mark it as processed now.
+  ClangModules.insert({PCMFile, getDwoId(CUDie)});
+
+  if (Error E =
+          loadClangModule(Loader, CUDie, PCMFile, OnCUDieLoaded, Indent + 2)) {
+    consumeError(std::move(E));
+    return false;
+  }
+  return true;
+}
+
+Error DWARFLinkerImpl::LinkContext::loadClangModule(
+    ObjFileLoaderTy Loader, const DWARFDie &CUDie, const std::string &PCMFile,
+    CompileUnitHandlerTy OnCUDieLoaded, unsigned Indent) {
+
+  uint64_t DwoId = getDwoId(CUDie);
+  std::string ModuleName = dwarf::toString(CUDie.find(dwarf::DW_AT_name), "");
+
+  /// Using a SmallString<0> because loadClangModule() is recursive.
+  SmallString<0> Path(GlobalData.getOptions().PrependPath);
+  if (sys::path::is_relative(PCMFile))
+    resolveRelativeObjectPath(Path, CUDie);
+  sys::path::append(Path, PCMFile);
+  // Don't use the cached binary holder because we have no thread-safety
+  // guarantee and the lifetime is limited.
+
+  if (Loader == nullptr) {
+    GlobalData.error("cann't load clang module: loader is not specified.",
+                     InputDWARFFile.FileName);
+    return Error::success();
+  }
+
+  auto ErrOrObj = Loader(InputDWARFFile.FileName, Path);
+  if (!ErrOrObj)
+    return Error::success();
+
+  std::unique_ptr<CompileUnit> Unit;
+  for (const auto &CU : ErrOrObj->Dwarf->compile_units()) {
+    OnCUDieLoaded(*CU);
+    // Recursively get all modules imported by this one.
+    auto ChildCUDie = CU->getUnitDIE();
+    if (!ChildCUDie)
+      continue;
+    if (!registerModuleReference(ChildCUDie, Loader, OnCUDieLoaded, Indent)) {
+      if (Unit) {
+        std::string Err =
+            (PCMFile +
+             ": Clang modules are expected to have exactly 1 compile unit.\n");
+        GlobalData.error(Err, InputDWARFFile.FileName);
+        return make_error<StringError>(Err, inconvertibleErrorCode());
+      }
+      // FIXME: Until PR27449 (https://llvm.org/bugs/show_bug.cgi?id=27449) is
+      // fixed in clang, only warn about DWO_id mismatches in verbose mode.
+      // ASTFileSignatures will change randomly when a module is rebuilt.
+      uint64_t PCMDwoId = getDwoId(ChildCUDie);
+      if (PCMDwoId != DwoId) {
+        if (GlobalData.getOptions().Verbose)
+          GlobalData.warn(
+              Twine("hash mismatch: this object file was built against a "
+                    "
diff erent version of the module ") +
+                  PCMFile + ".",
+              InputDWARFFile.FileName);
+        // Update the cache entry with the DwoId of the module loaded from disk.
+        ClangModules[PCMFile] = PCMDwoId;
+      }
+
+      // Empty modules units should not be cloned.
+      if (!ChildCUDie.hasChildren())
+        continue;
+
+      // Add this module.
+      Unit = std::make_unique<CompileUnit>(
+          GlobalData, *CU, UniqueUnitID.fetch_add(1), ModuleName, *ErrOrObj,
+          getUnitForOffset);
+    }
+  }
+
+  if (Unit) {
+    ModulesCompileUnits.emplace_back(RefModuleUnit{*ErrOrObj, std::move(Unit)});
+    // Preload line table, as it can't be loaded asynchronously.
+    ModulesCompileUnits.back().Unit->loadLineTable();
+  }
+
+  return Error::success();
+}
+
+Error DWARFLinkerImpl::LinkContext::link() {
+  InterCUProcessingStarted = false;
+  if (InputDWARFFile.Warnings.empty()) {
+    if (!InputDWARFFile.Dwarf)
+      return Error::success();
+
+    // Preload macro tables, as they can't be loaded asynchronously.
+    InputDWARFFile.Dwarf->getDebugMacinfo();
+    InputDWARFFile.Dwarf->getDebugMacro();
+
+    // Link modules compile units first.
+    parallelForEach(ModulesCompileUnits, [&](RefModuleUnit &RefModule) {
+      linkSingleCompileUnit(*RefModule.Unit);
+    });
+
+    // Check for live relocations. If there is no any live relocation then we
+    // can skip entire object file.
+    if (!GlobalData.getOptions().UpdateIndexTablesOnly &&
+        !InputDWARFFile.Addresses->hasValidRelocs()) {
+      if (GlobalData.getOptions().Verbose)
+        outs() << "No valid relocations found. Skipping.\n";
+      return Error::success();
+    }
+
+    OriginalDebugInfoSize = getInputDebugInfoSize();
+
+    // Create CompileUnit structures to keep information about source
+    // DWARFUnit`s, load line tables.
+    for (const auto &OrigCU : InputDWARFFile.Dwarf->compile_units()) {
+      // Load only unit DIE at this stage.
+      auto CUDie = OrigCU->getUnitDIE();
+      std::string PCMFile =
+          getPCMFile(CUDie, GlobalData.getOptions().ObjectPrefixMap);
+
+      // The !isClangModuleRef condition effectively skips over fully resolved
+      // skeleton units.
+      if (!CUDie || GlobalData.getOptions().UpdateIndexTablesOnly ||
+          !isClangModuleRef(CUDie, PCMFile, 0, true).first) {
+        CompileUnits.emplace_back(std::make_unique<CompileUnit>(
+            GlobalData, *OrigCU, UniqueUnitID.fetch_add(1), "", InputDWARFFile,
+            getUnitForOffset));
+
+        // Preload line table, as it can't be loaded asynchronously.
+        CompileUnits.back()->loadLineTable();
+      }
+    };
+
+    HasNewInterconnectedCUs = false;
+
+    // Link self-sufficient compile units and discover inter-connected compile
+    // units.
+    parallelForEach(CompileUnits, [&](std::unique_ptr<CompileUnit> &CU) {
+      linkSingleCompileUnit(*CU);
+    });
+
+    // Link all inter-connected units.
+    if (HasNewInterconnectedCUs) {
+      InterCUProcessingStarted = true;
+
+      do {
+        HasNewInterconnectedCUs = false;
+
+        // Load inter-connected units.
+        parallelForEach(CompileUnits, [&](std::unique_ptr<CompileUnit> &CU) {
+          if (CU->isInterconnectedCU()) {
+            CU->maybeResetToLoadedStage();
+            linkSingleCompileUnit(*CU, CompileUnit::Stage::Loaded);
+          }
+        });
+
+        // Do liveness analysis for inter-connected units.
+        parallelForEach(CompileUnits, [&](std::unique_ptr<CompileUnit> &CU) {
+          linkSingleCompileUnit(*CU, CompileUnit::Stage::LivenessAnalysisDone);
+        });
+      } while (HasNewInterconnectedCUs);
+
+      // Clone inter-connected units.
+      parallelForEach(CompileUnits, [&](std::unique_ptr<CompileUnit> &CU) {
+        linkSingleCompileUnit(*CU, CompileUnit::Stage::Cloned);
+      });
+
+      // Update patches for inter-connected units.
+      parallelForEach(CompileUnits, [&](std::unique_ptr<CompileUnit> &CU) {
+        linkSingleCompileUnit(*CU, CompileUnit::Stage::PatchesUpdated);
+      });
+
+      // Release data.
+      parallelForEach(CompileUnits, [&](std::unique_ptr<CompileUnit> &CU) {
+        linkSingleCompileUnit(*CU, CompileUnit::Stage::Cleaned);
+      });
+    }
+  }
+
+  if (!InputDWARFFile.Warnings.empty()) {
+    // Create compile unit with paper trail warnings.
+
+    Error ResultErr = Error::success();
+    // We use task group here as PerThreadBumpPtrAllocator should be called from
+    // the threads created by ThreadPoolExecutor.
+    parallel::TaskGroup TGroup;
+    TGroup.spawn([&]() {
+      if (Error Err = cloneAndEmitPaperTrails())
+        ResultErr = std::move(Err);
+    });
+    return ResultErr;
+  } else if (GlobalData.getOptions().UpdateIndexTablesOnly) {
+    // Emit Invariant sections.
+
+    if (Error Err = emitInvariantSections())
+      return Err;
+  } else if (!CompileUnits.empty()) {
+    // Emit .debug_frame section.
+
+    Error ResultErr = Error::success();
+    parallel::TaskGroup TGroup;
+    // We use task group here as PerThreadBumpPtrAllocator should be called from
+    // the threads created by ThreadPoolExecutor.
+    TGroup.spawn([&]() {
+      if (Error Err = cloneAndEmitDebugFrame())
+        ResultErr = std::move(Err);
+    });
+    return ResultErr;
+  }
+
+  return Error::success();
+}
+
+void DWARFLinkerImpl::LinkContext::linkSingleCompileUnit(
+    CompileUnit &CU, enum CompileUnit::Stage DoUntilStage) {
+  while (CU.getStage() < DoUntilStage) {
+    if (InterCUProcessingStarted != CU.isInterconnectedCU())
+      return;
+
+    switch (CU.getStage()) {
+    case CompileUnit::Stage::CreatedNotLoaded: {
+      // Load input compilation unit DIEs.
+      // Analyze properties of DIEs.
+      if (!CU.loadInputDIEs()) {
+        // We do not need to do liveness analysis for invalud compilation unit.
+        CU.setStage(CompileUnit::Stage::LivenessAnalysisDone);
+      } else {
+        CU.analyzeDWARFStructure();
+
+        // The registerModuleReference() condition effectively skips
+        // over fully resolved skeleton units. This second pass of
+        // registerModuleReferences doesn't do any new work, but it
+        // will collect top-level errors, which are suppressed. Module
+        // warnings were already displayed in the first iteration.
+        if (registerModuleReference(
+                CU.getOrigUnit().getUnitDIE(), nullptr,
+                [](const DWARFUnit &) {}, 0))
+          CU.setStage(CompileUnit::Stage::PatchesUpdated);
+        else
+          CU.setStage(CompileUnit::Stage::Loaded);
+      }
+    } break;
+
+    case CompileUnit::Stage::Loaded: {
+      // Mark all the DIEs that need to be present in the generated output.
+      // If ODR requested, build type names.
+      if (!DependencyTracker(*this).resolveDependenciesAndMarkLiveness(CU)) {
+        assert(HasNewInterconnectedCUs);
+        return;
+      }
+
+      CU.setStage(CompileUnit::Stage::LivenessAnalysisDone);
+    } break;
+
+    case CompileUnit::Stage::LivenessAnalysisDone:
+
+#ifndef NDEBUG
+      DependencyTracker::verifyKeepChain(CU);
+#endif
+
+      // Clone input compile unit.
+      if (CU.isClangModule() || GlobalData.getOptions().UpdateIndexTablesOnly ||
+          CU.getContaingFile().Addresses->hasValidRelocs()) {
+        if (Error Err = CU.cloneAndEmit(TargetTriple))
+          CU.error(std::move(Err));
+      }
+
+      CU.setStage(CompileUnit::Stage::Cloned);
+      break;
+
+    case CompileUnit::Stage::Cloned:
+      // Update DIEs referencies.
+      CU.updateDieRefPatchesWithClonedOffsets();
+      CU.setStage(CompileUnit::Stage::PatchesUpdated);
+      break;
+
+    case CompileUnit::Stage::PatchesUpdated:
+      // Cleanup resources.
+      CU.cleanupDataAfterClonning();
+      CU.setStage(CompileUnit::Stage::Cleaned);
+      break;
+
+    case CompileUnit::Stage::Cleaned:
+      assert(false);
+      break;
+    }
+  }
+}
+
+Error DWARFLinkerImpl::LinkContext::emitInvariantSections() {
+  if (GlobalData.getOptions().NoOutput)
+    return Error::success();
+
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugLoc).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getLocSection().Data;
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugLocLists).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getLoclistsSection().Data;
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugRange).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getRangesSection().Data;
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugRngLists).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getRnglistsSection().Data;
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugARanges).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getArangesSection();
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugFrame).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getFrameSection().Data;
+  getOrCreateSectionDescriptor(DebugSectionKind::DebugAddr).OS
+      << InputDWARFFile.Dwarf->getDWARFObj().getAddrSection().Data;
+
+  return Error::success();
+}
+
+Error DWARFLinkerImpl::LinkContext::cloneAndEmitDebugFrame() {
+  if (GlobalData.getOptions().NoOutput)
+    return Error::success();
+
+  if (InputDWARFFile.Dwarf.get() == nullptr)
+    return Error::success();
+
+  const DWARFObject &InputDWARFObj = InputDWARFFile.Dwarf->getDWARFObj();
+
+  StringRef OrigFrameData = InputDWARFObj.getFrameSection().Data;
+  if (OrigFrameData.empty())
+    return Error::success();
+
+  RangesTy AllUnitsRanges;
+  for (std::unique_ptr<CompileUnit> &Unit : CompileUnits) {
+    for (auto CurRange : Unit->getFunctionRanges())
+      AllUnitsRanges.insert(CurRange.Range, CurRange.Value);
+  }
+
+  unsigned SrcAddrSize = InputDWARFObj.getAddressSize();
+
+  SectionDescriptor &OutSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugFrame);
+
+  DataExtractor Data(OrigFrameData, InputDWARFObj.isLittleEndian(), 0);
+  uint64_t InputOffset = 0;
+
+  // Store the data of the CIEs defined in this object, keyed by their
+  // offsets.
+  DenseMap<uint64_t, StringRef> LocalCIES;
+
+  /// The CIEs that have been emitted in the output section. The actual CIE
+  /// data serves a the key to this StringMap.
+  StringMap<uint32_t> EmittedCIEs;
+
+  while (Data.isValidOffset(InputOffset)) {
+    uint64_t EntryOffset = InputOffset;
+    uint32_t InitialLength = Data.getU32(&InputOffset);
+    if (InitialLength == 0xFFFFFFFF)
+      return createFileError(InputDWARFObj.getFileName(),
+                             createStringError(std::errc::invalid_argument,
+                                               "Dwarf64 bits no supported"));
+
+    uint32_t CIEId = Data.getU32(&InputOffset);
+    if (CIEId == 0xFFFFFFFF) {
+      // This is a CIE, store it.
+      StringRef CIEData = OrigFrameData.substr(EntryOffset, InitialLength + 4);
+      LocalCIES[EntryOffset] = CIEData;
+      // The -4 is to account for the CIEId we just read.
+      InputOffset += InitialLength - 4;
+      continue;
+    }
+
+    uint64_t Loc = Data.getUnsigned(&InputOffset, SrcAddrSize);
+
+    // Some compilers seem to emit frame info that doesn't start at
+    // the function entry point, thus we can't just lookup the address
+    // in the debug map. Use the AddressInfo's range map to see if the FDE
+    // describes something that we can relocate.
+    std::optional<AddressRangeValuePair> Range =
+        AllUnitsRanges.getRangeThatContains(Loc);
+    if (!Range) {
+      // The +4 is to account for the size of the InitialLength field itself.
+      InputOffset = EntryOffset + InitialLength + 4;
+      continue;
+    }
+
+    // This is an FDE, and we have a mapping.
+    // Have we already emitted a corresponding CIE?
+    StringRef CIEData = LocalCIES[CIEId];
+    if (CIEData.empty())
+      return createFileError(
+          InputDWARFObj.getFileName(),
+          createStringError(std::errc::invalid_argument,
+                            "Inconsistent debug_frame content. Dropping."));
+
+    uint64_t OffsetToCIERecord = OutSection.OS.tell();
+
+    // Look if we already emitted a CIE that corresponds to the
+    // referenced one (the CIE data is the key of that lookup).
+    auto IteratorInserted =
+        EmittedCIEs.insert(std::make_pair(CIEData, OffsetToCIERecord));
+    OffsetToCIERecord = IteratorInserted.first->getValue();
+
+    // Emit CIE for this ID if it is not emitted yet.
+    if (IteratorInserted.second)
+      OutSection.OS << CIEData;
+
+    // Remember offset to the FDE record, so that we might update
+    // field referencing CIE record(containing OffsetToCIERecord),
+    // when final offsets are known. OffsetToCIERecord(which is written later)
+    // is local to the current .debug_frame section, it should be updated
+    // with final offset of the .debug_frame section.
+    OutSection.notePatch(
+        DebugOffsetPatch{OutSection.OS.tell() + 4, &OutSection, true});
+
+    // Emit the FDE with updated address and CIE pointer.
+    // (4 + AddrSize) is the size of the CIEId + initial_location
+    // fields that will get reconstructed by emitFDE().
+    unsigned FDERemainingBytes = InitialLength - (4 + SrcAddrSize);
+    emitFDE(OffsetToCIERecord, SrcAddrSize, Loc + Range->Value,
+            OrigFrameData.substr(InputOffset, FDERemainingBytes), OutSection);
+    InputOffset += FDERemainingBytes;
+  }
+
+  return Error::success();
+}
+
+/// Emit a FDE into the debug_frame section. \p FDEBytes
+/// contains the FDE data without the length, CIE offset and address
+/// which will be replaced with the parameter values.
+void DWARFLinkerImpl::LinkContext::emitFDE(uint32_t CIEOffset,
+                                           uint32_t AddrSize, uint64_t Address,
+                                           StringRef FDEBytes,
+                                           SectionDescriptor &Section) {
+  Section.emitIntVal(FDEBytes.size() + 4 + AddrSize, 4);
+  Section.emitIntVal(CIEOffset, 4);
+  Section.emitIntVal(Address, AddrSize);
+  Section.OS.write(FDEBytes.data(), FDEBytes.size());
+}
+
+Error DWARFLinkerImpl::LinkContext::cloneAndEmitPaperTrails() {
+
+  CompileUnits.emplace_back(
+      std::make_unique<CompileUnit>(GlobalData, UniqueUnitID.fetch_add(1), "",
+                                    InputDWARFFile, getUnitForOffset));
+
+  CompileUnit &CU = *CompileUnits.back();
+
+  BumpPtrAllocator Allocator;
+
+  DIEGenerator ParentGenerator(Allocator, CU);
+
+  SectionDescriptor &DebugInfoSection =
+      CU.getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo);
+  OffsetsPtrVector PatchesOffsets;
+
+  uint64_t CurrentOffset = CU.getDebugInfoHeaderSize();
+  DIE *CUDie =
+      ParentGenerator.createDIE(dwarf::DW_TAG_compile_unit, CurrentOffset);
+  CU.setOutUnitDIE(CUDie);
+
+  DebugInfoSection.notePatchWithOffsetUpdate(
+      DebugStrPatch{{CurrentOffset},
+                    GlobalData.getStringPool().insert("dsymutil").first},
+      PatchesOffsets);
+  CurrentOffset += ParentGenerator
+                       .addStringPlaceholderAttribute(dwarf::DW_AT_producer,
+                                                      dwarf::DW_FORM_strp)
+                       .second;
+
+  CurrentOffset +=
+      ParentGenerator
+          .addInplaceString(dwarf::DW_AT_name, InputDWARFFile.FileName)
+          .second;
+
+  size_t SizeAbbrevNumber = ParentGenerator.finalizeAbbreviations(true);
+  CurrentOffset += SizeAbbrevNumber;
+  for (uint64_t *OffsetPtr : PatchesOffsets)
+    *OffsetPtr += SizeAbbrevNumber;
+  for (const auto &Warning : CU.getContaingFile().Warnings) {
+    PatchesOffsets.clear();
+    DIEGenerator ChildGenerator(Allocator, CU);
+
+    DIE *ChildDie =
+        ChildGenerator.createDIE(dwarf::DW_TAG_constant, CurrentOffset);
+    ParentGenerator.addChild(ChildDie);
+
+    DebugInfoSection.notePatchWithOffsetUpdate(
+        DebugStrPatch{
+            {CurrentOffset},
+            GlobalData.getStringPool().insert("dsymutil_warning").first},
+        PatchesOffsets);
+    CurrentOffset += ChildGenerator
+                         .addStringPlaceholderAttribute(dwarf::DW_AT_name,
+                                                        dwarf::DW_FORM_strp)
+                         .second;
+
+    CurrentOffset +=
+        ChildGenerator
+            .addScalarAttribute(dwarf::DW_AT_artificial, dwarf::DW_FORM_flag, 1)
+            .second;
+
+    DebugInfoSection.notePatchWithOffsetUpdate(
+        DebugStrPatch{{CurrentOffset},
+                      GlobalData.getStringPool().insert(Warning).first},
+        PatchesOffsets);
+    CurrentOffset += ChildGenerator
+                         .addStringPlaceholderAttribute(
+                             dwarf::DW_AT_const_value, dwarf::DW_FORM_strp)
+                         .second;
+
+    SizeAbbrevNumber = ChildGenerator.finalizeAbbreviations(false);
+
+    CurrentOffset += SizeAbbrevNumber;
+    for (uint64_t *OffsetPtr : PatchesOffsets)
+      *OffsetPtr += SizeAbbrevNumber;
+
+    ChildDie->setSize(CurrentOffset - ChildDie->getOffset());
+  }
+
+  CurrentOffset += 1; // End of children
+  CUDie->setSize(CurrentOffset - CUDie->getOffset());
+
+  uint64_t UnitSize = 0;
+  UnitSize += CU.getDebugInfoHeaderSize();
+  UnitSize += CUDie->getSize();
+  CU.setUnitSize(UnitSize);
+
+  if (GlobalData.getOptions().NoOutput)
+    return Error::success();
+
+  if (Error Err = CU.emitDebugInfo(*TargetTriple))
+    return Err;
+
+  return CU.emitAbbreviations();
+}
+
+void DWARFLinkerImpl::glueCompileUnitsAndWriteToTheOutput() {
+  if (GlobalData.getOptions().NoOutput)
+    return;
+
+  // Go through all object files, all compile units and assign
+  // offsets to them.
+  assignOffsets();
+
+  // Patch size/offsets fields according to the assigned CU offsets.
+  patchOffsetsAndSizes();
+
+  // FIXME: Build accelerator tables.
+
+  // Emit common sections.
+  emitCommonSections();
+
+  // Cleanup data.
+  cleanupDataAfterOutputSectionsAreGenerated();
+
+  // Write debug tables from all object files/compile units into the
+  // resulting file.
+  writeDWARFToTheOutput();
+
+  if (GlobalData.getOptions().Statistics)
+    printStatistic();
+}
+
+void DWARFLinkerImpl::printStatistic() {
+
+  // For each object file map how many bytes were emitted.
+  StringMap<DebugInfoSize> SizeByObject;
+
+  for (const std::unique_ptr<LinkContext> &Context : ObjectContexts) {
+    uint64_t AllDebugInfoSectionsSize = 0;
+
+    for (std::unique_ptr<CompileUnit> &CU : Context->CompileUnits)
+      if (std::optional<SectionDescriptor *> DebugInfo =
+              CU->getSectionDescriptor(DebugSectionKind::DebugInfo))
+        AllDebugInfoSectionsSize += (*DebugInfo)->getContents().size();
+
+    SizeByObject[Context->InputDWARFFile.FileName].Input =
+        Context->OriginalDebugInfoSize;
+    SizeByObject[Context->InputDWARFFile.FileName].Output =
+        AllDebugInfoSectionsSize;
+  }
+
+  // Create a vector sorted in descending order by output size.
+  std::vector<std::pair<StringRef, DebugInfoSize>> Sorted;
+  for (auto &E : SizeByObject)
+    Sorted.emplace_back(E.first(), E.second);
+  llvm::sort(Sorted, [](auto &LHS, auto &RHS) {
+    return LHS.second.Output > RHS.second.Output;
+  });
+
+  auto ComputePercentange = [](int64_t Input, int64_t Output) -> float {
+    const float Difference = Output - Input;
+    const float Sum = Input + Output;
+    if (Sum == 0)
+      return 0;
+    return (Difference / (Sum / 2));
+  };
+
+  int64_t InputTotal = 0;
+  int64_t OutputTotal = 0;
+  const char *FormatStr = "{0,-45} {1,10}b  {2,10}b {3,8:P}\n";
+
+  // Print header.
+  outs() << ".debug_info section size (in bytes)\n";
+  outs() << "----------------------------------------------------------------"
+            "---------------\n";
+  outs() << "Filename                                           Object       "
+            "  dSYM   Change\n";
+  outs() << "----------------------------------------------------------------"
+            "---------------\n";
+
+  // Print body.
+  for (auto &E : Sorted) {
+    InputTotal += E.second.Input;
+    OutputTotal += E.second.Output;
+    llvm::outs() << formatv(
+        FormatStr, sys::path::filename(E.first).take_back(45), E.second.Input,
+        E.second.Output, ComputePercentange(E.second.Input, E.second.Output));
+  }
+  // Print total and footer.
+  outs() << "----------------------------------------------------------------"
+            "---------------\n";
+  llvm::outs() << formatv(FormatStr, "Total", InputTotal, OutputTotal,
+                          ComputePercentange(InputTotal, OutputTotal));
+  outs() << "----------------------------------------------------------------"
+            "---------------\n\n";
+}
+
+void DWARFLinkerImpl::assignOffsets() {
+  parallel::TaskGroup TGroup;
+  TGroup.spawn([&]() { assignOffsetsToStrings(); });
+  TGroup.spawn([&]() { assignOffsetsToSections(); });
+}
+
+void DWARFLinkerImpl::assignOffsetsToStrings() {
+  size_t CurDebugStrIndex = 1; // start from 1 to take into account zero entry.
+  uint64_t CurDebugStrOffset =
+      1; // start from 1 to take into account zero entry.
+  size_t CurDebugLineStrIndex = 0;
+  uint64_t CurDebugLineStrOffset = 0;
+
+  // To save space we do not create any separate string table.
+  // We use already allocated string patches and assign offsets
+  // to them in the natural order.
+  // ASSUMPTION: strings should be stored into .debug_str/.debug_line_str
+  // sections in the same order as they were assigned offsets.
+
+  forEachObjectSectionsSet([&](OutputSections &SectionsSet) {
+    SectionsSet.forEach([&](SectionDescriptor &OutSection) {
+      assignOffsetsToStringsImpl(OutSection.ListDebugStrPatch, CurDebugStrIndex,
+                                 CurDebugStrOffset, DebugStrStrings);
+
+      assignOffsetsToStringsImpl(OutSection.ListDebugLineStrPatch,
+                                 CurDebugLineStrIndex, CurDebugLineStrOffset,
+                                 DebugLineStrStrings);
+    });
+  });
+}
+
+template <typename PatchTy>
+void DWARFLinkerImpl::assignOffsetsToStringsImpl(
+    ArrayList<PatchTy> &Patches, size_t &IndexAccumulator,
+    uint64_t &OffsetAccumulator,
+    StringEntryToDwarfStringPoolEntryMap &StringsForEmission) {
+
+  // Enumerates all patches, adds string into the
+  // StringEntry->DwarfStringPoolEntry map, assign offset and index to the
+  // string if it is not indexed yet.
+  Patches.forEach([&](PatchTy &Patch) {
+    DwarfStringPoolEntryWithExtString *Entry =
+        StringsForEmission.add(Patch.String);
+    assert(Entry != nullptr);
+
+    if (!Entry->isIndexed()) {
+      Entry->Offset = OffsetAccumulator;
+      OffsetAccumulator += Entry->String.size() + 1;
+      Entry->Index = IndexAccumulator++;
+    }
+  });
+}
+
+void DWARFLinkerImpl::assignOffsetsToSections() {
+  std::array<uint64_t, SectionKindsNum> SectionSizesAccumulator = {0};
+
+  forEachObjectSectionsSet([&](OutputSections &UnitSections) {
+    UnitSections.assignSectionsOffsetAndAccumulateSize(SectionSizesAccumulator);
+  });
+}
+
+void DWARFLinkerImpl::forEachObjectSectionsSet(
+    function_ref<void(OutputSections &)> SectionsSetHandler) {
+  // Handle all modules first(before regular compilation units).
+  for (const std::unique_ptr<LinkContext> &Context : ObjectContexts)
+    for (LinkContext::RefModuleUnit &ModuleUnit : Context->ModulesCompileUnits)
+      SectionsSetHandler(*ModuleUnit.Unit);
+
+  for (const std::unique_ptr<LinkContext> &Context : ObjectContexts) {
+    // Handle object file common sections.
+    SectionsSetHandler(*Context);
+
+    // Handle compilation units.
+    for (std::unique_ptr<CompileUnit> &CU : Context->CompileUnits)
+      SectionsSetHandler(*CU);
+  }
+}
+
+void DWARFLinkerImpl::patchOffsetsAndSizes() {
+  forEachObjectSectionsSet([&](OutputSections &SectionsSet) {
+    SectionsSet.forEach([&](SectionDescriptor &OutSection) {
+      SectionsSet.applyPatches(OutSection, DebugStrStrings,
+                               DebugLineStrStrings);
+    });
+  });
+}
+
+template <typename PatchTy>
+void DWARFLinkerImpl::emitStringsImpl(
+    ArrayList<PatchTy> &StringPatches,
+    const StringEntryToDwarfStringPoolEntryMap &Strings, uint64_t &NextOffset,
+    SectionDescriptor &OutSection) {
+  // Enumerate all string patches and write strings into the destination
+  // section. We enumerate patches to have a predictable order of strings(i.e.
+  // strings are emitted in the order as they appear in the patches).
+  StringPatches.forEach([&](const PatchTy &Patch) {
+    DwarfStringPoolEntryWithExtString *StringToEmit =
+        Strings.getExistingEntry(Patch.String);
+    assert(StringToEmit->isIndexed());
+
+    // Patches can refer the same strings. We use accumulated NextOffset
+    // to understand whether corresponding string is already emitted.
+    // Skip patch if string is already emitted.
+    if (StringToEmit->Offset >= NextOffset) {
+      NextOffset = StringToEmit->Offset + StringToEmit->String.size() + 1;
+      // Emit the string itself.
+      OutSection.emitInplaceString(StringToEmit->String);
+    }
+  });
+}
+
+void DWARFLinkerImpl::emitCommonSections() {
+  parallel::TaskGroup TG;
+
+  SectionDescriptor &OutDebugStrSection =
+      CommonSections.getOrCreateSectionDescriptor(DebugSectionKind::DebugStr);
+  SectionDescriptor &OutDebugLineStrSection =
+      CommonSections.getOrCreateSectionDescriptor(
+          DebugSectionKind::DebugLineStr);
+
+  // Emit .debug_str section.
+  TG.spawn([&]() {
+    uint64_t DebugStrNextOffset = 0;
+
+    // Emit zero length string. Accelerator tables does not work correctly
+    // if the first string is not zero length string.
+    OutDebugStrSection.emitInplaceString("");
+    DebugStrNextOffset++;
+
+    forEachObjectSectionsSet([&](OutputSections &Sections) {
+      Sections.forEach([&](SectionDescriptor &Section) {
+        emitStringsImpl(Section.ListDebugStrPatch, DebugStrStrings,
+                        DebugStrNextOffset, OutDebugStrSection);
+      });
+    });
+  });
+
+  // Emit .debug_line_str section.
+  TG.spawn([&]() {
+    uint64_t DebugLineStrNextOffset = 0;
+
+    forEachObjectSectionsSet([&](OutputSections &Sections) {
+      Sections.forEach([&](SectionDescriptor &Section) {
+        emitStringsImpl(Section.ListDebugLineStrPatch, DebugLineStrStrings,
+                        DebugLineStrNextOffset, OutDebugLineStrSection);
+      });
+    });
+  });
+}
+
+void DWARFLinkerImpl::cleanupDataAfterOutputSectionsAreGenerated() {
+  GlobalData.getStringPool().clear();
+  DebugStrStrings.clear();
+  DebugLineStrStrings.clear();
+}
+
+void DWARFLinkerImpl::writeDWARFToTheOutput() {
+  bool HasAbbreviations = false;
+
+  forEachObjectSectionsSet([&](OutputSections &Sections) {
+    Sections.forEach([&](SectionDescriptor &OutSection) {
+      if (!HasAbbreviations && !OutSection.getContents().empty() &&
+          OutSection.getKind() == DebugSectionKind::DebugAbbrev)
+        HasAbbreviations = true;
+
+      // Emit section content.
+      TheDwarfEmitter->emitSectionContents(OutSection.getContents(),
+                                           OutSection.getName());
+      OutSection.erase();
+    });
+  });
+
+  CommonSections.forEach([&](SectionDescriptor &OutSection) {
+    // Emit section content.
+    TheDwarfEmitter->emitSectionContents(OutSection.getContents(),
+                                         OutSection.getName());
+    OutSection.erase();
+  });
+
+  if (!HasAbbreviations) {
+    const SmallVector<std::unique_ptr<DIEAbbrev>> Abbreviations;
+    TheDwarfEmitter->emitAbbrevs(Abbreviations, 3);
+  }
+}
+
 } // end of namespace dwarflinker_parallel
 } // namespace llvm

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.h b/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.h
index a8fa9b4b46d8a6..7e41eb11f239ea 100644
--- a/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.h
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerImpl.h
@@ -11,29 +11,29 @@
 
 #include "DWARFEmitterImpl.h"
 #include "DWARFLinkerCompileUnit.h"
+#include "StringEntryToDwarfStringPoolEntryMap.h"
 #include "llvm/ADT/AddressRanges.h"
 #include "llvm/CodeGen/AccelTable.h"
 #include "llvm/DWARFLinkerParallel/DWARFLinker.h"
 #include "llvm/DWARFLinkerParallel/StringPool.h"
-#include "llvm/DWARFLinkerParallel/StringTable.h"
 
 namespace llvm {
 namespace dwarflinker_parallel {
 
-using Offset2UnitMapTy = DenseMap<uint64_t, CompileUnit *>;
-
-struct RangeAttrPatch;
-struct LocAttrPatch;
-
+/// This class links debug info.
 class DWARFLinkerImpl : public DWARFLinker {
 public:
   DWARFLinkerImpl(MessageHandlerTy ErrorHandler,
                   MessageHandlerTy WarningHandler,
                   TranslatorFuncTy StringsTranslator)
-      : UniqueUnitID(0), ErrorHandler(ErrorHandler),
-        WarningHandler(WarningHandler),
-        OutputStrings(Strings, StringsTranslator) {}
+      : UniqueUnitID(0), DebugStrStrings(GlobalData),
+        DebugLineStrStrings(GlobalData), CommonSections(GlobalData) {
+    GlobalData.setTranslator(StringsTranslator);
+    GlobalData.setErrorHandler(ErrorHandler);
+    GlobalData.setWarningHandler(WarningHandler);
+  }
 
+  /// Create debug info emitter.
   Error createEmitter(const Triple &TheTriple, OutputFileType FileType,
                       raw_pwrite_stream &OutFile) override;
 
@@ -47,13 +47,11 @@ class DWARFLinkerImpl : public DWARFLinker {
   /// \pre NoODR, Update options should be set before call to addObjectFile.
   void addObjectFile(
       DWARFFile &File, ObjFileLoaderTy Loader = nullptr,
-      CompileUnitHandlerTy OnCUDieLoaded = [](const DWARFUnit &) {}) override {}
+
+      CompileUnitHandlerTy OnCUDieLoaded = [](const DWARFUnit &) {}) override;
 
   /// Link debug info for added files.
-  Error link() override {
-    reportWarning("LLVM parallel dwarflinker is not implemented yet.", "");
-    return Error::success();
-  }
+  Error link() override;
 
   /// \defgroup Methods setting various linking options:
   ///
@@ -61,51 +59,58 @@ class DWARFLinkerImpl : public DWARFLinker {
   ///
 
   /// Allows to generate log of linking process to the standard output.
-  void setVerbosity(bool Verbose) override { Options.Verbose = Verbose; }
+  void setVerbosity(bool Verbose) override {
+    GlobalData.Options.Verbose = Verbose;
+  }
 
   /// Print statistics to standard output.
   void setStatistics(bool Statistics) override {
-    Options.Statistics = Statistics;
+    GlobalData.Options.Statistics = Statistics;
   }
 
   /// Verify the input DWARF.
   void setVerifyInputDWARF(bool Verify) override {
-    Options.VerifyInputDWARF = Verify;
+    GlobalData.Options.VerifyInputDWARF = Verify;
   }
 
   /// Do not unique types according to ODR.
-  void setNoODR(bool NoODR) override { Options.NoODR = NoODR; }
+  void setNoODR(bool) override {
+    // FIXME: set option when ODR mode will be supported.
+    // getOptions().NoODR = NoODR;
+    GlobalData.Options.NoODR = true;
+  }
 
   /// Update index tables only(do not modify rest of DWARF).
   void setUpdateIndexTablesOnly(bool UpdateIndexTablesOnly) override {
-    Options.UpdateIndexTablesOnly = UpdateIndexTablesOnly;
+    GlobalData.Options.UpdateIndexTablesOnly = UpdateIndexTablesOnly;
   }
 
   /// Allow generating valid, but non-deterministic output.
   void
   setAllowNonDeterministicOutput(bool AllowNonDeterministicOutput) override {
-    Options.AllowNonDeterministicOutput = AllowNonDeterministicOutput;
+    GlobalData.Options.AllowNonDeterministicOutput =
+        AllowNonDeterministicOutput;
   }
 
   /// Set to keep the enclosing function for a static variable.
   void setKeepFunctionForStatic(bool KeepFunctionForStatic) override {
-    Options.KeepFunctionForStatic = KeepFunctionForStatic;
+    GlobalData.Options.KeepFunctionForStatic = KeepFunctionForStatic;
   }
 
   /// Use specified number of threads for parallel files linking.
   void setNumThreads(unsigned NumThreads) override {
-    Options.Threads = NumThreads;
+    GlobalData.Options.Threads = NumThreads;
   }
 
   /// Add kind of accelerator tables to be generated.
   void addAccelTableKind(AccelTableKind Kind) override {
-    assert(!llvm::is_contained(Options.AccelTables, Kind));
-    Options.AccelTables.emplace_back(Kind);
+    assert(!llvm::is_contained(GlobalData.getOptions().AccelTables, Kind));
+    GlobalData.Options.AccelTables.emplace_back(Kind);
   }
 
   /// Set prepend path for clang modules.
   void setPrependPath(const std::string &Ppath) override {
-    Options.PrependPath = Ppath;
+    GlobalData.Options.PrependPath = Ppath;
   }
 
   /// Set estimated objects files amount, for preliminary data allocation.
@@ -117,17 +122,17 @@ class DWARFLinkerImpl : public DWARFLinker {
   /// errors.
   void
   setInputVerificationHandler(InputVerificationHandlerTy Handler) override {
-    Options.InputVerificationHandler = Handler;
+    GlobalData.Options.InputVerificationHandler = Handler;
   }
 
   /// Set map for Swift interfaces.
   void setSwiftInterfacesMap(SwiftInterfacesMapTy *Map) override {
-    Options.ParseableSwiftInterfaces = Map;
+    GlobalData.Options.ParseableSwiftInterfaces = Map;
   }
 
   /// Set prefix map for objects.
   void setObjectPrefixMap(ObjectPrefixMapTy *Map) override {
-    Options.ObjectPrefixMap = Map;
+    GlobalData.Options.ObjectPrefixMap = Map;
   }
 
   /// Set target DWARF version.
@@ -137,36 +142,28 @@ class DWARFLinkerImpl : public DWARFLinker {
                                "unsupported DWARF version: %d",
                                TargetDWARFVersion);
 
-    Options.TargetDWARFVersion = TargetDWARFVersion;
+    GlobalData.Options.TargetDWARFVersion = TargetDWARFVersion;
     return Error::success();
   }
   /// @}
 
 protected:
-  /// Reports Warning.
-  void reportWarning(const Twine &Warning, const DWARFFile &File,
-                     const DWARFDie *DIE = nullptr) const {
-    if (WarningHandler != nullptr)
-      WarningHandler(Warning, File.FileName, DIE);
-  }
+  /// Verify input DWARF file.
+  void verifyInput(const DWARFFile &File);
 
-  /// Reports Warning.
-  void reportWarning(const Twine &Warning, StringRef FileName,
-                     const DWARFDie *DIE = nullptr) const {
-    if (WarningHandler != nullptr)
-      WarningHandler(Warning, FileName, DIE);
-  }
+  /// Validate specified options.
+  Error validateAndUpdateOptions();
 
-  /// Reports Error.
-  void reportError(const Twine &Warning, StringRef FileName,
-                   const DWARFDie *DIE = nullptr) const {
-    if (ErrorHandler != nullptr)
-      ErrorHandler(Warning, FileName, DIE);
-  }
+  /// Take already linked compile units and glue them into single file.
+  void glueCompileUnitsAndWriteToTheOutput();
 
-  /// Returns next available unique Compile Unit ID.
-  unsigned getNextUniqueUnitID() { return UniqueUnitID.fetch_add(1); }
+  /// Hold the input and output of the debug info size in bytes.
+  struct DebugInfoSize {
+    uint64_t Input;
+    uint64_t Output;
+  };
 
+  friend class DependencyTracker;
   /// Keeps track of data associated with one object during linking.
   /// i.e. source file descriptor, compilation units, output data
   /// for compilation units common tables.
@@ -188,7 +185,7 @@ class DWARFLinkerImpl : public DWARFLinker {
     using ModuleUnitListTy = SmallVector<RefModuleUnit>;
 
     /// Object file descriptor.
-    DWARFFile &File;
+    DWARFFile &InputDWARFFile;
 
     /// Set of Compilation Units(may be accessed asynchroniously for reading).
     UnitListTy CompileUnits;
@@ -199,117 +196,190 @@ class DWARFLinkerImpl : public DWARFLinker {
     /// Size of Debug info before optimizing.
     uint64_t OriginalDebugInfoSize = 0;
 
-    /// Output sections, common for all compilation units.
-    OutTablesFileTy OutDebugInfoBytes;
+    /// Flag indicating that all inter-connected units are loaded
+    /// and the dwarf linking process for these units is started.
+    bool InterCUProcessingStarted = false;
+
+    StringMap<uint64_t> &ClangModules;
+
+    std::optional<Triple> TargetTriple;
+
+    /// Flag indicating that new inter-connected compilation units were
+    /// discovered. It is used for restarting units processing
+    /// if new inter-connected units were found.
+    std::atomic<bool> HasNewInterconnectedCUs = {false};
 
-    /// Endianness for the final file.
-    support::endianness Endianess = support::endianness::little;
+    /// Counter for compile units ID.
+    std::atomic<size_t> &UniqueUnitID;
+
+    LinkContext(LinkingGlobalData &GlobalData, DWARFFile &File,
+                StringMap<uint64_t> &ClangModules,
+                std::atomic<size_t> &UniqueUnitID,
+                std::optional<Triple> TargetTriple)
+        : OutputSections(GlobalData), InputDWARFFile(File),
+          ClangModules(ClangModules), TargetTriple(TargetTriple),
+          UniqueUnitID(UniqueUnitID) {
 
-    LinkContext(DWARFFile &File) : File(File) {
       if (File.Dwarf) {
         if (!File.Dwarf->compile_units().empty())
           CompileUnits.reserve(File.Dwarf->getNumCompileUnits());
-
-        Endianess = File.Dwarf->isLittleEndian() ? support::endianness::little
-                                                 : support::endianness::big;
       }
     }
 
+    /// Check whether specified \p CUDie is a Clang module reference.
+    /// if \p Quiet is false then display error messages.
+    /// \return first == true if CUDie is a Clang module reference.
+    ///         second == true if module is already loaded.
+    std::pair<bool, bool> isClangModuleRef(const DWARFDie &CUDie,
+                                           std::string &PCMFile,
+                                           unsigned Indent, bool Quiet);
+
+    /// If this compile unit is really a skeleton CU that points to a
+    /// clang module, register it in ClangModules and return true.
+    ///
+    /// A skeleton CU is a CU without children, a DW_AT_gnu_dwo_name
+    /// pointing to the module, and a DW_AT_gnu_dwo_id with the module
+    /// hash.
+    bool registerModuleReference(const DWARFDie &CUDie, ObjFileLoaderTy Loader,
+                                 CompileUnitHandlerTy OnCUDieLoaded,
+                                 unsigned Indent = 0);
+
+    /// Recursively add the debug info in this clang module .pcm
+    /// file (and all the modules imported by it in a bottom-up fashion)
+    /// to ModuleUnits.
+    Error loadClangModule(ObjFileLoaderTy Loader, const DWARFDie &CUDie,
+                          const std::string &PCMFile,
+                          CompileUnitHandlerTy OnCUDieLoaded,
+                          unsigned Indent = 0);
+
     /// Add Compile Unit corresponding to the module.
     void addModulesCompileUnit(RefModuleUnit &&Unit) {
       ModulesCompileUnits.emplace_back(std::move(Unit));
     }
 
-    /// Return Endiannes of the source DWARF information.
-    support::endianness getEndianness() { return Endianess; }
+    /// Computes the total size of the debug info.
+    uint64_t getInputDebugInfoSize() const {
+      uint64_t Size = 0;
 
-    /// \returns pointer to compilation unit which corresponds \p Offset.
-    CompileUnit *getUnitForOffset(CompileUnit &CU, uint64_t Offset) const;
-  };
+      if (InputDWARFFile.Dwarf == nullptr)
+        return Size;
+
+      for (auto &Unit : InputDWARFFile.Dwarf->compile_units())
+        Size += Unit->getLength();
+
+      return Size;
+    }
 
-  /// linking options
-  struct DWARFLinkerOptions {
-    /// DWARF version for the output.
-    uint16_t TargetDWARFVersion = 0;
+    /// Link compile units for this context.
+    Error link();
 
-    /// Generate processing log to the standard output.
-    bool Verbose = false;
+    /// Link specified compile unit until specified stage.
+    void linkSingleCompileUnit(
+        CompileUnit &CU,
+        enum CompileUnit::Stage DoUntilStage = CompileUnit::Stage::Cleaned);
 
-    /// Print statistics.
-    bool Statistics = false;
+    /// Emit invariant sections.
+    Error emitInvariantSections();
 
-    /// Verify the input DWARF.
-    bool VerifyInputDWARF = false;
+    /// Clone and emit .debug_frame.
+    Error cloneAndEmitDebugFrame();
 
-    /// Do not unique types according to ODR
-    bool NoODR = false;
+    /// Emit FDE record.
+    void emitFDE(uint32_t CIEOffset, uint32_t AddrSize, uint64_t Address,
+                 StringRef FDEBytes, SectionDescriptor &Section);
 
-    /// Update index tables.
-    bool UpdateIndexTablesOnly = false;
+    /// Clone and emit paper trails.
+    Error cloneAndEmitPaperTrails();
 
-    /// Whether we want a static variable to force us to keep its enclosing
-    /// function.
-    bool KeepFunctionForStatic = false;
+    std::function<CompileUnit *(uint64_t)> getUnitForOffset =
+        [&](uint64_t Offset) -> CompileUnit * {
+      auto CU = llvm::upper_bound(
+          CompileUnits, Offset,
+          [](uint64_t LHS, const std::unique_ptr<CompileUnit> &RHS) {
+            return LHS < RHS->getOrigUnit().getNextUnitOffset();
+          });
 
-    /// Allow to generate valid, but non deterministic output.
-    bool AllowNonDeterministicOutput = false;
+      return CU != CompileUnits.end() ? CU->get() : nullptr;
+    };
+  };
 
-    /// Number of threads.
-    unsigned Threads = 1;
+  /// Enumerate all compile units and assign offsets to their sections and
+  /// strings.
+  void assignOffsets();
 
-    /// The accelerator table kinds
-    SmallVector<AccelTableKind, 1> AccelTables;
+  /// Enumerate all compile units and assign offsets to their sections.
+  void assignOffsetsToSections();
 
-    /// Prepend path for the clang modules.
-    std::string PrependPath;
+  /// Enumerate all compile units and assign offsets to their strings.
+  void assignOffsetsToStrings();
 
-    /// input verification handler(it might be called asynchronously).
-    InputVerificationHandlerTy InputVerificationHandler = nullptr;
+  /// Enumerates specified string patches, assigns offset and index.
+  template <typename PatchTy>
+  void assignOffsetsToStringsImpl(
+      ArrayList<PatchTy> &Section, size_t &IndexAccumulator,
+      uint64_t &OffsetAccumulator,
+      StringEntryToDwarfStringPoolEntryMap &StringsForEmission);
 
-    /// A list of all .swiftinterface files referenced by the debug
-    /// info, mapping Module name to path on disk. The entries need to
-    /// be uniqued and sorted and there are only few entries expected
-    /// per compile unit, which is why this is a std::map.
-    /// this is dsymutil specific fag.
-    ///
-    /// (it might be called asynchronously).
-    SwiftInterfacesMapTy *ParseableSwiftInterfaces = nullptr;
+  /// Print statistic for processed Debug Info.
+  void printStatistic();
 
-    /// A list of remappings to apply to file paths.
-    ///
-    /// (it might be called asynchronously).
-    ObjectPrefixMapTy *ObjectPrefixMap = nullptr;
-  } Options;
+  /// Enumerates sections for modules, invariant for object files, compile
+  /// units.
+  void forEachObjectSectionsSet(
+      function_ref<void(OutputSections &SectionsSet)> SectionsSetHandler);
+
+  /// Enumerates all patches and update them with the correct values.
+  void patchOffsetsAndSizes();
+
+  /// Emit debug sections common for all input files.
+  void emitCommonSections();
+
+  /// Cleanup data(string pools) after output sections are generated.
+  void cleanupDataAfterOutputSectionsAreGenerated();
+
+  /// Enumerate all compile units and put their data into the output stream.
+  void writeDWARFToTheOutput();
+
+  template <typename PatchTy>
+  void emitStringsImpl(ArrayList<PatchTy> &StringPatches,
+                       const StringEntryToDwarfStringPoolEntryMap &Strings,
+                       uint64_t &NextOffset, SectionDescriptor &OutSection);
 
   /// \defgroup Data members accessed asinchroniously.
   ///
   /// @{
 
   /// Unique ID for compile unit.
-  std::atomic<unsigned> UniqueUnitID;
-
-  /// Strings pool. Keeps all strings.
-  StringPool Strings;
+  std::atomic<size_t> UniqueUnitID;
 
-  /// error handler(it might be called asynchronously).
-  MessageHandlerTy ErrorHandler = nullptr;
-
-  /// warning handler(it might be called asynchronously).
-  MessageHandlerTy WarningHandler = nullptr;
+  /// Mapping the PCM filename to the DwoId.
+  StringMap<uint64_t> ClangModules;
+  std::mutex ClangModulesMutex;
   /// @}
 
   /// \defgroup Data members accessed sequentially.
   ///
   /// @{
+  /// DwarfStringPoolEntries for .debug_str section.
+  StringEntryToDwarfStringPoolEntryMap DebugStrStrings;
 
-  /// Set of strings which should be emitted.
-  StringTable OutputStrings;
+  /// DwarfStringPoolEntries for .debug_line_str section.
+  StringEntryToDwarfStringPoolEntryMap DebugLineStrStrings;
 
   /// Keeps all linking contexts.
   SmallVector<std::unique_ptr<LinkContext>> ObjectContexts;
 
+  /// Common sections.
+  OutputSections CommonSections;
+
   /// The emitter of final dwarf file.
   std::unique_ptr<DwarfEmitterImpl> TheDwarfEmitter;
+
+  /// Overall compile units number.
+  uint64_t OverallNumberOfCU = 0;
+
+  /// Data global for the whole linking process.
+  LinkingGlobalData GlobalData;
   /// @}
 };
 

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.cpp b/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.cpp
new file mode 100644
index 00000000000000..e16c237d1a43f7
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.cpp
@@ -0,0 +1,130 @@
+//===- DWARFLinkerUnit.cpp ------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DWARFLinkerUnit.h"
+#include "DWARFEmitterImpl.h"
+#include "DebugLineSectionEmitter.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+void DwarfUnit::assignAbbrev(DIEAbbrev &Abbrev) {
+  // Check the set for priors.
+  FoldingSetNodeID ID;
+  Abbrev.Profile(ID);
+  void *InsertToken;
+
+  DIEAbbrev *InSet = AbbreviationsSet.FindNodeOrInsertPos(ID, InsertToken);
+  // If it's newly added.
+  if (InSet) {
+    // Assign existing abbreviation number.
+    Abbrev.setNumber(InSet->getNumber());
+  } else {
+    // Add to abbreviation list.
+    Abbreviations.push_back(
+        std::make_unique<DIEAbbrev>(Abbrev.getTag(), Abbrev.hasChildren()));
+    for (const auto &Attr : Abbrev.getData())
+      Abbreviations.back()->AddAttribute(Attr);
+    AbbreviationsSet.InsertNode(Abbreviations.back().get(), InsertToken);
+    // Assign the unique abbreviation number.
+    Abbrev.setNumber(Abbreviations.size());
+    Abbreviations.back()->setNumber(Abbreviations.size());
+  }
+}
+
+Error DwarfUnit::emitAbbreviations() {
+  const std::vector<std::unique_ptr<DIEAbbrev>> &Abbrevs = getAbbreviations();
+  if (Abbrevs.empty())
+    return Error::success();
+
+  SectionDescriptor &AbbrevSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugAbbrev);
+
+  // For each abbreviation.
+  for (const auto &Abbrev : Abbrevs)
+    emitDwarfAbbrevEntry(*Abbrev, AbbrevSection);
+
+  // Mark end of abbreviations.
+  encodeULEB128(0, AbbrevSection.OS);
+
+  return Error::success();
+}
+
+void DwarfUnit::emitDwarfAbbrevEntry(const DIEAbbrev &Abbrev,
+                                     SectionDescriptor &AbbrevSection) {
+  // Emit the abbreviations code (base 1 index.)
+  encodeULEB128(Abbrev.getNumber(), AbbrevSection.OS);
+
+  // Emit the abbreviations data.
+  // Emit its Dwarf tag type.
+  encodeULEB128(Abbrev.getTag(), AbbrevSection.OS);
+
+  // Emit whether it has children DIEs.
+  encodeULEB128((unsigned)Abbrev.hasChildren(), AbbrevSection.OS);
+
+  // For each attribute description.
+  const SmallVectorImpl<DIEAbbrevData> &Data = Abbrev.getData();
+  for (unsigned i = 0, N = Data.size(); i < N; ++i) {
+    const DIEAbbrevData &AttrData = Data[i];
+
+    // Emit attribute type.
+    encodeULEB128(AttrData.getAttribute(), AbbrevSection.OS);
+
+    // Emit form type.
+    encodeULEB128(AttrData.getForm(), AbbrevSection.OS);
+
+    // Emit value for DW_FORM_implicit_const.
+    if (AttrData.getForm() == dwarf::DW_FORM_implicit_const)
+      encodeSLEB128(AttrData.getValue(), AbbrevSection.OS);
+  }
+
+  // Mark end of abbreviation.
+  encodeULEB128(0, AbbrevSection.OS);
+  encodeULEB128(0, AbbrevSection.OS);
+}
+
+Error DwarfUnit::emitDebugInfo(Triple &TargetTriple) {
+  DIE *OutUnitDIE = getOutUnitDIE();
+  if (OutUnitDIE == nullptr)
+    return Error::success();
+
+  // FIXME: Remove dependence on DwarfEmitterImpl/AsmPrinter and emit DIEs
+  // directly.
+
+  SectionDescriptor &OutSection =
+      getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo);
+  DwarfEmitterImpl Emitter(DWARFLinker::OutputFileType::Object, OutSection.OS);
+  if (Error Err = Emitter.init(TargetTriple, "__DWARF"))
+    return Err;
+
+  // Emit compile unit header.
+  Emitter.emitCompileUnitHeader(*this);
+  size_t OffsetToAbbreviationTableOffset =
+      (getFormParams().Version >= 5) ? 8 : 6;
+  OutSection.notePatch(DebugOffsetPatch{
+      OffsetToAbbreviationTableOffset,
+      &getOrCreateSectionDescriptor(DebugSectionKind::DebugAbbrev)});
+
+  // Emit DIEs.
+  Emitter.emitDIE(*OutUnitDIE);
+  Emitter.finish();
+
+  // Set start offset ans size for .debug_info section.
+  OutSection.setSizesForSectionCreatedByAsmPrinter();
+  return Error::success();
+}
+
+Error DwarfUnit::emitDebugLine(Triple &TargetTriple,
+                               const DWARFDebugLine::LineTable &OutLineTable) {
+  DebugLineSectionEmitter DebugLineEmitter(TargetTriple, *this);
+
+  return DebugLineEmitter.emit(OutLineTable);
+}
+
+} // end of namespace dwarflinker_parallel
+} // end of namespace llvm

diff  --git a/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.h b/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.h
index 78e8d82ea06158..50aa6957b3dc28 100644
--- a/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.h
+++ b/llvm/lib/DWARFLinkerParallel/DWARFLinkerUnit.h
@@ -9,9 +9,11 @@
 #ifndef LLVM_LIB_DWARFLINKERPARALLEL_DWARFLINKERUNIT_H
 #define LLVM_LIB_DWARFLINKERPARALLEL_DWARFLINKERUNIT_H
 
+#include "DWARFLinkerGlobalData.h"
 #include "OutputSections.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/CodeGen/DIE.h"
+#include "llvm/DWARFLinkerParallel/DWARFLinker.h"
 #include "llvm/DWARFLinkerParallel/StringPool.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 #include "llvm/Support/LEB128.h"
@@ -19,44 +21,17 @@
 namespace llvm {
 namespace dwarflinker_parallel {
 
-using UnitMessageHandlerTy = function_ref<void(
-    const Twine &Error, StringRef Context, const DWARFDie *DIE)>;
-
-/// Each unit keeps output data as a file with debug tables
-/// corresponding to the concrete unit.
-using OutTablesFileTy = SmallString<0>;
+class DwarfUnit;
+using MacroOffset2UnitMapTy = DenseMap<uint64_t, DwarfUnit *>;
 
 /// Base class for all Dwarf units(Compile unit/Type table unit).
 class DwarfUnit : public OutputSections {
 public:
   virtual ~DwarfUnit() {}
-  DwarfUnit(unsigned ID, StringRef ClangModuleName,
-            UnitMessageHandlerTy WarningHandler)
-      : ID(ID), ClangModuleName(ClangModuleName),
-        WarningHandler(WarningHandler) {
-    FormParams.Version = 4;
-    FormParams.Format = dwarf::DWARF32;
-    FormParams.AddrSize = 4;
-  }
-
-  /// Endiannes for the compile unit.
-  support::endianness getEndianness() const { return Endianess; }
-
-  /// Return DWARF version.
-  uint16_t getVersion() const { return FormParams.Version; }
-
-  /// Return size of header of debug_info table.
-  uint16_t getHeaderSize() const { return FormParams.Version >= 5 ? 12 : 11; }
-
-  /// Return size of address.
-  uint8_t getAddressByteSize() const { return FormParams.AddrSize; }
-
-  /// Return size of reference.
-  uint8_t getRefAddrByteSize() const { return FormParams.getRefAddrByteSize(); }
-
-  /// Return format of the Dwarf(DWARF32 or DWARF64).
-  /// TODO: DWARF64 is not currently supported.
-  dwarf::DwarfFormat getDwarfFormat() const { return FormParams.Format; }
+  DwarfUnit(LinkingGlobalData &GlobalData, unsigned ID,
+            StringRef ClangModuleName)
+      : OutputSections(GlobalData), ID(ID), ClangModuleName(ClangModuleName),
+        OutUnitDIE(nullptr) {}
 
   /// Unique id of the unit.
   unsigned getUniqueID() const { return ID; }
@@ -76,41 +51,48 @@ class DwarfUnit : public OutputSections {
   /// Return the DW_AT_LLVM_sysroot of the compile unit or an empty StringRef.
   StringRef getSysRoot() { return SysRoot; }
 
-  /// Create a Die for this unit.
-  void setOutputDIE(DIE *UnitDie) { NewUnit = UnitDie; }
-
-  /// Return Die for this compile unit.
-  DIE *getOutputUnitDIE() const { return NewUnit; }
-
   /// Return true if this compile unit is from Clang module.
   bool isClangModule() const { return !ClangModuleName.empty(); }
 
   /// Return Clang module name;
   const std::string &getClangModuleName() const { return ClangModuleName; }
 
-  /// Returns generated file keeping debug tables for this compile unit.
-  OutTablesFileTy &getOutDwarfBits() { return OutDebugInfoBits; }
+  /// Return global data.
+  LinkingGlobalData &getGlobalData() { return GlobalData; }
 
-  /// Erases generated file keeping debug tables for this compile unit.
-  void eraseDwarfBits() { OutDebugInfoBits = OutTablesFileTy(); }
+  /// Returns true if unit is inter-connected(it references/referenced by other
+  /// unit).
+  bool isInterconnectedCU() const { return IsInterconnectedCU; }
 
-  MCSymbol *getLabelBegin() { return LabelBegin; }
-  void setLabelBegin(MCSymbol *S) { LabelBegin = S; }
+  /// Mark this unit as inter-connected(it references/referenced by other unit).
+  void setInterconnectedCU() { IsInterconnectedCU = true; }
 
-  /// Error reporting methods.
-  /// @{
+  /// Adds \p Abbrev into unit`s abbreviation table.
+  void assignAbbrev(DIEAbbrev &Abbrev);
 
-  void reportWarning(const Twine &Warning,
-                     const DWARFDie *Die = nullptr) const {
-    if (WarningHandler)
-      WarningHandler(Warning, getUnitName(), Die);
-  }
-  void reportWarning(Error Warning) const {
-    handleAllErrors(std::move(Warning), [&](ErrorInfoBase &Info) {
-      if (WarningHandler)
-        WarningHandler(Info.message(), getUnitName(), nullptr);
-    });
+  /// Returns abbreviations for this compile unit.
+  const std::vector<std::unique_ptr<DIEAbbrev>> &getAbbreviations() const {
+    return Abbreviations;
   }
+
+  /// Returns output unit DIE.
+  DIE *getOutUnitDIE() { return OutUnitDIE; }
+
+  /// Set output unit DIE.
+  void setOutUnitDIE(DIE *UnitDie) { OutUnitDIE = UnitDie; }
+
+  /// \defgroup Methods used to emit unit's debug info:
+  ///
+  /// @{
+  /// Emit unit's abbreviations.
+  Error emitAbbreviations();
+
+  /// Emit .debug_info section for unit DIEs.
+  Error emitDebugInfo(Triple &TargetTriple);
+
+  /// Emit .debug_line section.
+  Error emitDebugLine(Triple &TargetTriple,
+                      const DWARFDebugLine::LineTable &OutLineTable);
   /// @}
 
   /// This structure keeps fields which would be used for creating accelerator
@@ -142,16 +124,22 @@ class DwarfUnit : public OutputSections {
     const DIE *Die = nullptr;
   };
 
+  /// \defgroup Methods used for reporting warnings and errors:
+  ///
+  /// @{
+  void warn(const Twine &Warning) { GlobalData.warn(Warning, getUnitName()); }
+
+  void error(const Twine &Err) { GlobalData.warn(Err, getUnitName()); }
+  /// @}
+
 protected:
+  /// Emit single abbreviation entry.
+  void emitDwarfAbbrevEntry(const DIEAbbrev &Abbrev,
+                            SectionDescriptor &AbbrevSection);
+
   /// Unique ID for the unit.
   unsigned ID = 0;
 
-  /// Properties of the unit.
-  dwarf::FormParams FormParams;
-
-  /// DIE for newly generated compile unit.
-  DIE *NewUnit = nullptr;
-
   /// The DW_AT_language of this unit.
   uint16_t Language = 0;
 
@@ -166,18 +154,17 @@ class DwarfUnit : public OutputSections {
 
   uint64_t UnitSize = 0;
 
-  /// Elf file containg generated debug tables for this compile unit.
-  OutTablesFileTy OutDebugInfoBits;
-
-  /// Endiannes for this compile unit.
-  support::endianness Endianess = support::endianness::little;
-
-  MCSymbol *LabelBegin = nullptr;
-
   /// true if current unit references_to/is_referenced by other unit.
   std::atomic<bool> IsInterconnectedCU = {false};
 
-  UnitMessageHandlerTy WarningHandler;
+  /// FoldingSet that uniques the abbreviations.
+  FoldingSet<DIEAbbrev> AbbreviationsSet;
+
+  /// Storage for the unique Abbreviations.
+  std::vector<std::unique_ptr<DIEAbbrev>> Abbreviations;
+
+  /// Output unit DIE.
+  DIE *OutUnitDIE = nullptr;
 };
 
 } // end of namespace dwarflinker_parallel

diff  --git a/llvm/lib/DWARFLinkerParallel/DebugLineSectionEmitter.h b/llvm/lib/DWARFLinkerParallel/DebugLineSectionEmitter.h
new file mode 100644
index 00000000000000..f1fcd91753900d
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DebugLineSectionEmitter.h
@@ -0,0 +1,384 @@
+//===- DebugLineSectionEmitter.h --------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_DEBUGLINESECTIONEMITTER_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_DEBUGLINESECTIONEMITTER_H
+
+#include "DWARFEmitterImpl.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/DWARFLinkerParallel/AddressesMap.h"
+#include "llvm/DWARFLinkerParallel/DWARFLinker.h"
+#include "llvm/DebugInfo/DWARF/DWARFObject.h"
+#include "llvm/MC/MCTargetOptionsCommandFlags.h"
+#include "llvm/MC/TargetRegistry.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+/// This class emits specified line table into the .debug_line section.
+class DebugLineSectionEmitter {
+public:
+  DebugLineSectionEmitter(const Triple &TheTriple, DwarfUnit &U)
+      : TheTriple(TheTriple), U(U) {}
+
+  Error emit(const DWARFDebugLine::LineTable &LineTable) {
+    // FIXME: remove dependence on MCDwarfLineAddr::encode.
+    // As we reuse MCDwarfLineAddr::encode, we need to create/initialize
+    // some MC* classes.
+    if (Error Err = init(TheTriple))
+      return Err;
+
+    // Get descriptor for output .debug_line section.
+    SectionDescriptor &OutSection =
+        U.getOrCreateSectionDescriptor(DebugSectionKind::DebugLine);
+
+    // unit_length.
+    OutSection.emitUnitLength(0xBADDEF);
+    uint64_t OffsetAfterUnitLength = OutSection.OS.tell();
+
+    // Emit prologue.
+    emitLineTablePrologue(LineTable.Prologue, OutSection);
+
+    // Emit rows.
+    emitLineTableRows(LineTable, OutSection);
+    uint64_t OffsetAfterEnd = OutSection.OS.tell();
+
+    // Update unit length field with actual length value.
+    assert(OffsetAfterUnitLength -
+               OutSection.getFormParams().getDwarfOffsetByteSize() <
+           OffsetAfterUnitLength);
+    OutSection.apply(OffsetAfterUnitLength -
+                         OutSection.getFormParams().getDwarfOffsetByteSize(),
+                     dwarf::DW_FORM_sec_offset,
+                     OffsetAfterEnd - OffsetAfterUnitLength);
+
+    return Error::success();
+  }
+
+private:
+  Error init(Triple TheTriple) {
+    std::string ErrorStr;
+    std::string TripleName;
+
+    // Get the target.
+    const Target *TheTarget =
+        TargetRegistry::lookupTarget(TripleName, TheTriple, ErrorStr);
+    if (!TheTarget)
+      return createStringError(std::errc::invalid_argument, ErrorStr.c_str());
+    TripleName = TheTriple.getTriple();
+
+    // Create all the MC Objects.
+    MRI.reset(TheTarget->createMCRegInfo(TripleName));
+    if (!MRI)
+      return createStringError(std::errc::invalid_argument,
+                               "no register info for target %s",
+                               TripleName.c_str());
+
+    MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags();
+    MAI.reset(TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
+    if (!MAI)
+      return createStringError(std::errc::invalid_argument,
+                               "no asm info for target %s", TripleName.c_str());
+
+    MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
+    if (!MSTI)
+      return createStringError(std::errc::invalid_argument,
+                               "no subtarget info for target %s",
+                               TripleName.c_str());
+
+    MC.reset(new MCContext(TheTriple, MAI.get(), MRI.get(), MSTI.get(), nullptr,
+                           nullptr, true, "__DWARF"));
+
+    return Error::success();
+  }
+
+  void emitLineTablePrologue(const DWARFDebugLine::Prologue &P,
+                             SectionDescriptor &Section) {
+    // version (uhalf).
+    Section.emitIntVal(P.getVersion(), 2);
+    if (P.getVersion() == 5) {
+      // address_size (ubyte).
+      Section.emitIntVal(P.getAddressSize(), 1);
+
+      // segment_selector_size (ubyte).
+      Section.emitIntVal(P.SegSelectorSize, 1);
+    }
+
+    // header_length.
+    Section.emitOffset(0xBADDEF);
+
+    uint64_t OffsetAfterPrologueLength = Section.OS.tell();
+    emitLineTableProloguePayload(P, Section);
+    uint64_t OffsetAfterPrologueEnd = Section.OS.tell();
+
+    // Update prologue length field with actual length value.
+    Section.apply(OffsetAfterPrologueLength -
+                      Section.getFormParams().getDwarfOffsetByteSize(),
+                  dwarf::DW_FORM_sec_offset,
+                  OffsetAfterPrologueEnd - OffsetAfterPrologueLength);
+  }
+
+  void
+  emitLineTablePrologueV2IncludeAndFileTable(const DWARFDebugLine::Prologue &P,
+                                             SectionDescriptor &Section) {
+    // include_directories (sequence of path names).
+    for (const DWARFFormValue &Include : P.IncludeDirectories) {
+      std::optional<const char *> IncludeStr = dwarf::toString(Include);
+      if (!IncludeStr) {
+        U.warn("cann't read string from line table.");
+        return;
+      }
+
+      Section.emitString(Include.getForm(), *IncludeStr);
+    }
+    // The last entry is followed by a single null byte.
+    Section.emitIntVal(0, 1);
+
+    // file_names (sequence of file entries).
+    for (const DWARFDebugLine::FileNameEntry &File : P.FileNames) {
+      std::optional<const char *> FileNameStr = dwarf::toString(File.Name);
+      if (!FileNameStr) {
+        U.warn("cann't read string from line table.");
+        return;
+      }
+
+      // A null-terminated string containing the full or relative path name of a
+      // source file.
+      Section.emitString(File.Name.getForm(), *FileNameStr);
+      // An unsigned LEB128 number representing the directory index of a
+      // directory in the include_directories section.
+      encodeULEB128(File.DirIdx, Section.OS);
+      // An unsigned LEB128 number representing the (implementation-defined)
+      // time of last modification for the file, or 0 if not available.
+      encodeULEB128(File.ModTime, Section.OS);
+      // An unsigned LEB128 number representing the length in bytes of the file,
+      // or 0 if not available.
+      encodeULEB128(File.Length, Section.OS);
+    }
+    // The last entry is followed by a single null byte.
+    Section.emitIntVal(0, 1);
+  }
+
+  void
+  emitLineTablePrologueV5IncludeAndFileTable(const DWARFDebugLine::Prologue &P,
+                                             SectionDescriptor &Section) {
+    if (P.IncludeDirectories.empty()) {
+      // directory_entry_format_count(ubyte).
+      Section.emitIntVal(0, 1);
+    } else {
+      // directory_entry_format_count(ubyte).
+      Section.emitIntVal(1, 1);
+
+      // directory_entry_format (sequence of ULEB128 pairs).
+      encodeULEB128(dwarf::DW_LNCT_path, Section.OS);
+      encodeULEB128(P.IncludeDirectories[0].getForm(), Section.OS);
+    }
+
+    // directories_count (ULEB128).
+    encodeULEB128(P.IncludeDirectories.size(), Section.OS);
+    // directories (sequence of directory names).
+    for (auto Include : P.IncludeDirectories) {
+      std::optional<const char *> IncludeStr = dwarf::toString(Include);
+      if (!IncludeStr) {
+        U.warn("cann't read string from line table.");
+        return;
+      }
+
+      Section.emitString(Include.getForm(), *IncludeStr);
+    }
+
+    if (P.FileNames.empty()) {
+      // file_name_entry_format_count (ubyte).
+      Section.emitIntVal(0, 1);
+    } else {
+      // file_name_entry_format_count (ubyte).
+      Section.emitIntVal(2, 1);
+
+      // file_name_entry_format (sequence of ULEB128 pairs).
+      encodeULEB128(dwarf::DW_LNCT_path, Section.OS);
+      encodeULEB128(P.FileNames[0].Name.getForm(), Section.OS);
+
+      encodeULEB128(dwarf::DW_LNCT_directory_index, Section.OS);
+      encodeULEB128(dwarf::DW_FORM_data1, Section.OS);
+    }
+
+    // file_names_count (ULEB128).
+    encodeULEB128(P.FileNames.size(), Section.OS);
+
+    // file_names (sequence of file name entries).
+    for (auto File : P.FileNames) {
+      std::optional<const char *> FileNameStr = dwarf::toString(File.Name);
+      if (!FileNameStr) {
+        U.warn("cann't read string from line table.");
+        return;
+      }
+
+      // A null-terminated string containing the full or relative path name of a
+      // source file.
+      Section.emitString(File.Name.getForm(), *FileNameStr);
+      Section.emitIntVal(File.DirIdx, 1);
+    }
+  }
+
+  void emitLineTableProloguePayload(const DWARFDebugLine::Prologue &P,
+                                    SectionDescriptor &Section) {
+    // minimum_instruction_length (ubyte).
+    Section.emitIntVal(P.MinInstLength, 1);
+    if (P.FormParams.Version >= 4) {
+      // maximum_operations_per_instruction (ubyte).
+      Section.emitIntVal(P.MaxOpsPerInst, 1);
+    }
+    // default_is_stmt (ubyte).
+    Section.emitIntVal(P.DefaultIsStmt, 1);
+    // line_base (sbyte).
+    Section.emitIntVal(P.LineBase, 1);
+    // line_range (ubyte).
+    Section.emitIntVal(P.LineRange, 1);
+    // opcode_base (ubyte).
+    Section.emitIntVal(P.OpcodeBase, 1);
+
+    // standard_opcode_lengths (array of ubyte).
+    for (auto Length : P.StandardOpcodeLengths)
+      Section.emitIntVal(Length, 1);
+
+    if (P.FormParams.Version < 5)
+      emitLineTablePrologueV2IncludeAndFileTable(P, Section);
+    else
+      emitLineTablePrologueV5IncludeAndFileTable(P, Section);
+  }
+
+  void emitLineTableRows(const DWARFDebugLine::LineTable &LineTable,
+                         SectionDescriptor &Section) {
+
+    MCDwarfLineTableParams Params;
+    Params.DWARF2LineOpcodeBase = LineTable.Prologue.OpcodeBase;
+    Params.DWARF2LineBase = LineTable.Prologue.LineBase;
+    Params.DWARF2LineRange = LineTable.Prologue.LineRange;
+
+    SmallString<128> EncodingBuffer;
+
+    if (LineTable.Rows.empty()) {
+      // We only have the dummy entry, dsymutil emits an entry with a 0
+      // address in that case.
+      MCDwarfLineAddr::encode(*MC, Params, std::numeric_limits<int64_t>::max(),
+                              0, EncodingBuffer);
+      Section.OS.write(EncodingBuffer.c_str(), EncodingBuffer.size());
+      return;
+    }
+
+    // Line table state machine fields
+    unsigned FileNum = 1;
+    unsigned LastLine = 1;
+    unsigned Column = 0;
+    unsigned IsStatement = 1;
+    unsigned Isa = 0;
+    uint64_t Address = -1ULL;
+
+    unsigned RowsSinceLastSequence = 0;
+
+    for (const DWARFDebugLine::Row &Row : LineTable.Rows) {
+      int64_t AddressDelta;
+      if (Address == -1ULL) {
+        Section.emitIntVal(dwarf::DW_LNS_extended_op, 1);
+        encodeULEB128(Section.getFormParams().AddrSize + 1, Section.OS);
+        Section.emitIntVal(dwarf::DW_LNE_set_address, 1);
+        Section.emitIntVal(Row.Address.Address,
+                           Section.getFormParams().AddrSize);
+        AddressDelta = 0;
+      } else {
+        AddressDelta =
+            (Row.Address.Address - Address) / LineTable.Prologue.MinInstLength;
+      }
+
+      // FIXME: code copied and transformed from
+      // MCDwarf.cpp::EmitDwarfLineTable. We should find a way to share this
+      // code, but the current compatibility requirement with classic dsymutil
+      // makes it hard. Revisit that once this requirement is dropped.
+
+      if (FileNum != Row.File) {
+        FileNum = Row.File;
+        Section.emitIntVal(dwarf::DW_LNS_set_file, 1);
+        encodeULEB128(FileNum, Section.OS);
+      }
+      if (Column != Row.Column) {
+        Column = Row.Column;
+        Section.emitIntVal(dwarf::DW_LNS_set_column, 1);
+        encodeULEB128(Column, Section.OS);
+      }
+
+      // FIXME: We should handle the discriminator here, but dsymutil doesn't
+      // consider it, thus ignore it for now.
+
+      if (Isa != Row.Isa) {
+        Isa = Row.Isa;
+        Section.emitIntVal(dwarf::DW_LNS_set_isa, 1);
+        encodeULEB128(Isa, Section.OS);
+      }
+      if (IsStatement != Row.IsStmt) {
+        IsStatement = Row.IsStmt;
+        Section.emitIntVal(dwarf::DW_LNS_negate_stmt, 1);
+      }
+      if (Row.BasicBlock)
+        Section.emitIntVal(dwarf::DW_LNS_set_basic_block, 1);
+
+      if (Row.PrologueEnd)
+        Section.emitIntVal(dwarf::DW_LNS_set_prologue_end, 1);
+
+      if (Row.EpilogueBegin)
+        Section.emitIntVal(dwarf::DW_LNS_set_epilogue_begin, 1);
+
+      int64_t LineDelta = int64_t(Row.Line) - LastLine;
+      if (!Row.EndSequence) {
+        MCDwarfLineAddr::encode(*MC, Params, LineDelta, AddressDelta,
+                                EncodingBuffer);
+        Section.OS.write(EncodingBuffer.c_str(), EncodingBuffer.size());
+        EncodingBuffer.resize(0);
+        Address = Row.Address.Address;
+        LastLine = Row.Line;
+        RowsSinceLastSequence++;
+      } else {
+        if (LineDelta) {
+          Section.emitIntVal(dwarf::DW_LNS_advance_line, 1);
+          encodeSLEB128(LineDelta, Section.OS);
+        }
+        if (AddressDelta) {
+          Section.emitIntVal(dwarf::DW_LNS_advance_pc, 1);
+          encodeULEB128(AddressDelta, Section.OS);
+        }
+        MCDwarfLineAddr::encode(*MC, Params,
+                                std::numeric_limits<int64_t>::max(), 0,
+                                EncodingBuffer);
+        Section.OS.write(EncodingBuffer.c_str(), EncodingBuffer.size());
+        EncodingBuffer.resize(0);
+        Address = -1ULL;
+        LastLine = FileNum = IsStatement = 1;
+        RowsSinceLastSequence = Column = Isa = 0;
+      }
+    }
+
+    if (RowsSinceLastSequence) {
+      MCDwarfLineAddr::encode(*MC, Params, std::numeric_limits<int64_t>::max(),
+                              0, EncodingBuffer);
+      Section.OS.write(EncodingBuffer.c_str(), EncodingBuffer.size());
+      EncodingBuffer.resize(0);
+    }
+  }
+
+  Triple TheTriple;
+  DwarfUnit &U;
+
+  std::unique_ptr<MCRegisterInfo> MRI;
+  std::unique_ptr<MCAsmInfo> MAI;
+  std::unique_ptr<MCContext> MC;
+  std::unique_ptr<MCSubtargetInfo> MSTI;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_DEBUGLINESECTIONEMITTER_H

diff  --git a/llvm/lib/DWARFLinkerParallel/DependencyTracker.cpp b/llvm/lib/DWARFLinkerParallel/DependencyTracker.cpp
new file mode 100644
index 00000000000000..4bf353afbe42b0
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DependencyTracker.cpp
@@ -0,0 +1,428 @@
+//=== DependencyTracker.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DependencyTracker.h"
+#include "llvm/Support/FormatVariadic.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+#ifndef NDEBUG
+/// A broken link in the keep chain. By recording both the parent and the child
+/// we can show only broken links for DIEs with multiple children.
+struct BrokenLink {
+  BrokenLink(DWARFDie Parent, DWARFDie Child) : Parent(Parent), Child(Child) {}
+  DWARFDie Parent;
+  DWARFDie Child;
+};
+
+/// Verify the keep chain by looking for DIEs that are kept but who's parent
+/// isn't.
+void DependencyTracker::verifyKeepChain(CompileUnit &CU) {
+  SmallVector<DWARFDie> Worklist;
+  Worklist.push_back(CU.getOrigUnit().getUnitDIE());
+
+  // List of broken links.
+  SmallVector<BrokenLink> BrokenLinks;
+
+  while (!Worklist.empty()) {
+    const DWARFDie Current = Worklist.back();
+    Worklist.pop_back();
+
+    if (!Current.isValid())
+      continue;
+
+    const bool CurrentDieIsKept = CU.getDIEInfo(Current).getKeep() ||
+                                  CU.getDIEInfo(Current).getKeepChildren();
+
+    for (DWARFDie Child : reverse(Current.children())) {
+      Worklist.push_back(Child);
+
+      const bool ChildDieIsKept = CU.getDIEInfo(Child).getKeep() ||
+                                  CU.getDIEInfo(Child).getKeepChildren();
+      if (!CurrentDieIsKept && ChildDieIsKept)
+        BrokenLinks.emplace_back(Current, Child);
+    }
+  }
+
+  if (!BrokenLinks.empty()) {
+    for (BrokenLink Link : BrokenLinks) {
+      WithColor::error() << formatv(
+          "Found invalid link in keep chain between {0:x} and {1:x}\n",
+          Link.Parent.getOffset(), Link.Child.getOffset());
+
+      errs() << "Parent:";
+      Link.Parent.dump(errs(), 0, {});
+      CU.getDIEInfo(Link.Parent).dump();
+
+      errs() << "Child:";
+      Link.Child.dump(errs(), 2, {});
+      CU.getDIEInfo(Link.Child).dump();
+    }
+    report_fatal_error("invalid keep chain");
+  }
+}
+#endif
+
+bool DependencyTracker::resolveDependenciesAndMarkLiveness(CompileUnit &CU) {
+  // We do not track liveness inside Clang modules. We also do not track
+  // liveness if UpdateIndexTablesOnly is requested.
+  TrackLiveness = !(CU.isClangModule() ||
+                    CU.getGlobalData().getOptions().UpdateIndexTablesOnly);
+  RootEntriesWorkList.clear();
+
+  // Search for live root DIEs.
+  collectRootsToKeep(CU, CU.getDebugInfoEntry(0));
+
+  // Mark live DIEs as kept.
+  return markLiveRootsAsKept();
+}
+
+void DependencyTracker::collectRootsToKeep(CompileUnit &CU,
+                                           const DWARFDebugInfoEntry *Entry) {
+  if (!TrackLiveness) {
+    addItemToWorklist(CU, Entry);
+    return;
+  }
+
+  switch (Entry->getTag()) {
+  case dwarf::DW_TAG_subprogram:
+  case dwarf::DW_TAG_label:
+    if (isLiveSubprogramEntry(CU, Entry)) {
+      addItemToWorklist(CU, Entry);
+      break;
+    }
+    [[fallthrough]];
+  case dwarf::DW_TAG_compile_unit:
+  case dwarf::DW_TAG_namespace:
+  case dwarf::DW_TAG_module:
+  case dwarf::DW_TAG_lexical_block: {
+    for (const DWARFDebugInfoEntry *CurChild = CU.getFirstChildEntry(Entry);
+         CurChild && CurChild->getAbbreviationDeclarationPtr();
+         CurChild = CU.getSiblingEntry(CurChild))
+      collectRootsToKeep(CU, CurChild);
+  } break;
+  case dwarf::DW_TAG_constant:
+  case dwarf::DW_TAG_variable: {
+    if (isLiveVariableEntry(CU, Entry))
+      addItemToWorklist(CU, Entry);
+  } break;
+  case dwarf::DW_TAG_base_type: {
+    addItemToWorklist(CU, Entry);
+  } break;
+  case dwarf::DW_TAG_imported_module:
+  case dwarf::DW_TAG_imported_declaration:
+  case dwarf::DW_TAG_imported_unit: {
+    addItemToWorklist(CU, Entry);
+  } break;
+  default:
+    // Nothing to do.
+    break;
+  }
+}
+
+bool DependencyTracker::markLiveRootsAsKept() {
+  bool Res = true;
+
+  while (!RootEntriesWorkList.empty()) {
+    RootEntryTy CurrentItem = RootEntriesWorkList.pop_back_val();
+
+    if (!markDIEEntryAsKeptRec(CurrentItem, CurrentItem.CU,
+                               CurrentItem.RootEntry))
+      Res = false;
+  }
+
+  return Res;
+}
+
+bool DependencyTracker::markDIEEntryAsKeptRec(
+    const RootEntryTy &RootItem, CompileUnit &CU,
+    const DWARFDebugInfoEntry *Entry) {
+  if (Entry->getAbbreviationDeclarationPtr() == nullptr)
+    return true;
+
+  CompileUnit::DIEInfo &Info = CU.getDIEInfo(Entry);
+
+  if (Info.getKeep())
+    return true;
+
+  // Mark parents as 'KeepChildren'.
+  std::optional<uint32_t> ParentIdx = Entry->getParentIdx();
+  while (ParentIdx) {
+    const DWARFDebugInfoEntry *ParentEntry = CU.getDebugInfoEntry(*ParentIdx);
+    CompileUnit::DIEInfo &ParentInfo = CU.getDIEInfo(*ParentIdx);
+    if (ParentInfo.getKeepChildren())
+      break;
+    ParentInfo.setKeepChildren();
+    ParentIdx = ParentEntry->getParentIdx();
+  }
+
+  // Mark current DIE as kept.
+  Info.setKeep();
+  setDIEPlacementAndTypename(Info);
+
+  // Set liveness information.
+  switch (Entry->getTag()) {
+  case dwarf::DW_TAG_constant:
+  case dwarf::DW_TAG_variable: {
+    isLiveVariableEntry(CU, Entry);
+  } break;
+  case dwarf::DW_TAG_subprogram:
+  case dwarf::DW_TAG_label: {
+    isLiveSubprogramEntry(CU, Entry);
+  } break;
+  default:
+    // Nothing to do.
+    break;
+  }
+
+  // Analyse referenced DIEs.
+  bool Res = true;
+  if (!maybeAddReferencedRoots(RootItem, CU, Entry))
+    Res = false;
+
+  // Navigate children.
+  for (const DWARFDebugInfoEntry *CurChild = CU.getFirstChildEntry(Entry);
+       CurChild && CurChild->getAbbreviationDeclarationPtr();
+       CurChild = CU.getSiblingEntry(CurChild)) {
+    if (!markDIEEntryAsKeptRec(RootItem, CU, CurChild))
+      Res = false;
+  }
+
+  return Res;
+}
+
+bool DependencyTracker::maybeAddReferencedRoots(
+    const RootEntryTy &RootItem, CompileUnit &CU,
+    const DWARFDebugInfoEntry *Entry) {
+  const auto *Abbrev = Entry->getAbbreviationDeclarationPtr();
+  if (Abbrev == nullptr)
+    return true;
+
+  DWARFUnit &Unit = CU.getOrigUnit();
+  DWARFDataExtractor Data = Unit.getDebugInfoExtractor();
+  uint64_t Offset = Entry->getOffset() + getULEB128Size(Abbrev->getCode());
+
+  // For each DIE attribute...
+  for (const auto &AttrSpec : Abbrev->attributes()) {
+    DWARFFormValue Val(AttrSpec.Form);
+    if (!Val.isFormClass(DWARFFormValue::FC_Reference) ||
+        AttrSpec.Attr == dwarf::DW_AT_sibling) {
+      DWARFFormValue::skipValue(AttrSpec.Form, Data, &Offset,
+                                Unit.getFormParams());
+      continue;
+    }
+    Val.extractValue(Data, &Offset, Unit.getFormParams(), &Unit);
+
+    // Resolve reference.
+    std::optional<std::pair<CompileUnit *, uint32_t>> RefDie =
+        CU.resolveDIEReference(Val);
+    if (!RefDie) {
+      CU.warn("cann't find referenced DIE", Entry);
+      continue;
+    }
+
+    if (CU.getUniqueID() == RefDie->first->getUniqueID()) {
+      // Check if referenced DIE entry is already kept.
+      if (RefDie->first->getDIEInfo(RefDie->second).getKeep())
+        continue;
+
+      // If referenced DIE is inside current compilation unit.
+      const DWARFDebugInfoEntry *RefEntry =
+          RefDie->first->getDebugInfoEntry(RefDie->second);
+
+      if (RootItem.RootEntry->getTag() == dwarf::DW_TAG_compile_unit)
+        addItemToWorklist(*RefDie->first, RefEntry);
+      else {
+        uint64_t RootStartOffset = RootItem.RootEntry->getOffset();
+        uint64_t RootEndOffset;
+        if (std::optional<uint32_t> SiblingIdx =
+                RootItem.RootEntry->getSiblingIdx()) {
+          RootEndOffset =
+              RootItem.CU.getDebugInfoEntry(*SiblingIdx)->getOffset();
+        } else {
+          RootEndOffset = RootItem.CU.getOrigUnit().getNextUnitOffset();
+        }
+
+        // Do not put item in work list if it is an ancestor of RootItem.
+        // (since we will visit and mark it as kept during normal traversing of
+        // RootItem children)
+        if (RootStartOffset > RefEntry->getOffset() ||
+            RefEntry->getOffset() >= RootEndOffset)
+          addItemToWorklist(*RefDie->first, RefEntry);
+      }
+    } else if (Context.InterCUProcessingStarted && RefDie->second != 0) {
+      // If referenced DIE is in other compilation unit and
+      // it is safe to navigate other units DIEs.
+      addItemToWorklist(*RefDie->first,
+                        RefDie->first->getDebugInfoEntry(RefDie->second));
+    } else {
+      // Delay resolving reference.
+      RefDie->first->setInterconnectedCU();
+      CU.setInterconnectedCU();
+      Context.HasNewInterconnectedCUs = true;
+      return false;
+    }
+  }
+
+  return true;
+}
+
+// Returns true if the specified DIE type allows removing children.
+static bool childrenCanBeRemoved(uint32_t Tag) {
+  switch (Tag) {
+  default:
+    return true;
+  case dwarf::DW_TAG_class_type:
+  case dwarf::DW_TAG_common_block:
+  case dwarf::DW_TAG_lexical_block:
+  case dwarf::DW_TAG_structure_type:
+  case dwarf::DW_TAG_subprogram:
+  case dwarf::DW_TAG_subroutine_type:
+  case dwarf::DW_TAG_union_type:
+  case dwarf::DW_TAG_array_type:
+    return false;
+  }
+  llvm_unreachable("Invalid Tag");
+}
+
+void DependencyTracker::addItemToWorklist(CompileUnit &CU,
+                                          const DWARFDebugInfoEntry *Entry) {
+  if (Entry->getAbbreviationDeclarationPtr() == nullptr)
+    return;
+
+  const DWARFDebugInfoEntry *EntryToAdd = Entry;
+
+  // If parent does not allow children removing then use that parent as a root
+  // DIE.
+  std::optional<uint32_t> ParentIdx = Entry->getParentIdx();
+  while (ParentIdx) {
+    const DWARFDebugInfoEntry *ParentEntry = CU.getDebugInfoEntry(*ParentIdx);
+    if (childrenCanBeRemoved(ParentEntry->getTag()))
+      break;
+    EntryToAdd = ParentEntry;
+    ParentIdx = ParentEntry->getParentIdx();
+  }
+
+  // Check if the DIE entry is already kept.
+  if (CU.getDIEInfo(EntryToAdd).getKeep())
+    return;
+
+  RootEntriesWorkList.emplace_back(CU, EntryToAdd);
+}
+
+bool DependencyTracker::isLiveVariableEntry(CompileUnit &CU,
+                                            const DWARFDebugInfoEntry *Entry) {
+  DWARFDie DIE = CU.getDIE(Entry);
+  CompileUnit::DIEInfo &Info = CU.getDIEInfo(DIE);
+
+  if (TrackLiveness) {
+    const auto *Abbrev = DIE.getAbbreviationDeclarationPtr();
+
+    // Global variables with constant value can always be kept.
+    if (!Info.getIsInFunctionScope() &&
+        Abbrev->findAttributeIndex(dwarf::DW_AT_const_value))
+      return true;
+
+    // See if there is a relocation to a valid debug map entry inside this
+    // variable's location. The order is important here. We want to always check
+    // if the variable has a location expression address.
+    // However, we don't want a static variable in a function to force us to
+    // keep the enclosing function, unless requested explicitly.
+    std::pair<bool, std::optional<int64_t>> LocExprAddrAndRelocAdjustment =
+        CU.getContaingFile().Addresses->getVariableRelocAdjustment(DIE);
+
+    if (!LocExprAddrAndRelocAdjustment.second)
+      return false;
+
+    if ((Info.getIsInFunctionScope()) &&
+        !LLVM_UNLIKELY(CU.getGlobalData().getOptions().KeepFunctionForStatic))
+      return false;
+  }
+
+  if (CU.getGlobalData().getOptions().Verbose) {
+    outs() << "Keeping variable DIE:";
+    DIDumpOptions DumpOpts;
+    DumpOpts.ChildRecurseDepth = 0;
+    DumpOpts.Verbose = CU.getGlobalData().getOptions().Verbose;
+    DIE.dump(outs(), 8 /* Indent */, DumpOpts);
+  }
+
+  return true;
+}
+
+bool DependencyTracker::isLiveSubprogramEntry(
+    CompileUnit &CU, const DWARFDebugInfoEntry *Entry) {
+  DWARFDie DIE = CU.getDIE(Entry);
+
+  std::optional<uint64_t> LowPc;
+  std::optional<uint64_t> HighPc;
+  std::optional<int64_t> RelocAdjustment;
+
+  if (TrackLiveness) {
+    LowPc = dwarf::toAddress(DIE.find(dwarf::DW_AT_low_pc));
+    if (!LowPc)
+      return false;
+
+    RelocAdjustment =
+        CU.getContaingFile().Addresses->getSubprogramRelocAdjustment(DIE);
+    if (!RelocAdjustment)
+      return false;
+
+    if (DIE.getTag() == dwarf::DW_TAG_subprogram) {
+      // Validate subprogram address range.
+
+      HighPc = DIE.getHighPC(*LowPc);
+      if (!HighPc) {
+        CU.warn("function without high_pc. Range will be discarded.", &DIE);
+        return false;
+      }
+
+      if (*LowPc > *HighPc) {
+        CU.warn("low_pc greater than high_pc. Range will be discarded.", &DIE);
+        return false;
+      }
+    } else if (DIE.getTag() == dwarf::DW_TAG_variable) {
+      if (CU.hasLabelAt(*LowPc))
+        return false;
+
+      // FIXME: dsymutil-classic compat. dsymutil-classic doesn't consider
+      // labels that don't fall into the CU's aranges. This is wrong IMO. Debug
+      // info generation bugs aside, this is really wrong in the case of labels,
+      // where a label marking the end of a function will have a PC == CU's
+      // high_pc.
+      if (dwarf::toAddress(
+              CU.getOrigUnit().getUnitDIE().find(dwarf::DW_AT_high_pc))
+              .value_or(UINT64_MAX) <= LowPc)
+        return false;
+
+      CU.addLabelLowPc(*LowPc, *RelocAdjustment);
+    }
+  }
+
+  if (CU.getGlobalData().getOptions().Verbose) {
+    outs() << "Keeping subprogram DIE:";
+    DIDumpOptions DumpOpts;
+    DumpOpts.ChildRecurseDepth = 0;
+    DumpOpts.Verbose = CU.getGlobalData().getOptions().Verbose;
+    DIE.dump(outs(), 8 /* Indent */, DumpOpts);
+  }
+
+  if (!TrackLiveness || DIE.getTag() == dwarf::DW_TAG_label)
+    return true;
+
+  CU.addFunctionRange(*LowPc, *HighPc, *RelocAdjustment);
+  return true;
+}
+
+void DependencyTracker::setDIEPlacementAndTypename(CompileUnit::DIEInfo &Info) {
+  Info.setPlacement(CompileUnit::PlainDwarf);
+}
+
+} // end of namespace dwarflinker_parallel
+} // namespace llvm

diff  --git a/llvm/lib/DWARFLinkerParallel/DependencyTracker.h b/llvm/lib/DWARFLinkerParallel/DependencyTracker.h
new file mode 100644
index 00000000000000..69e57bc3ea4d26
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/DependencyTracker.h
@@ -0,0 +1,102 @@
+//===- "DependencyTracker.h" ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_DEPENDENCYTRACKER_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_DEPENDENCYTRACKER_H
+
+#include "DWARFLinkerCompileUnit.h"
+#include "DWARFLinkerImpl.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace llvm {
+class DWARFDebugInfoEntry;
+class DWARFDie;
+
+namespace dwarflinker_parallel {
+
+/// This class discovers DIEs dependencies and marks "live" DIEs.
+class DependencyTracker {
+public:
+  DependencyTracker(DWARFLinkerImpl::LinkContext &Context) : Context(Context) {}
+
+  /// Recursively walk the \p DIE tree and look for DIEs to keep. Store that
+  /// information in \p CU's DIEInfo.
+  ///
+  /// This function is the entry point of the DIE selection algorithm. It is
+  /// expected to walk the DIE tree and(through the mediation of
+  /// Context.File.Addresses) ask for relocation adjustment value on each
+  /// DIE that might be a 'root DIE'.
+  ///
+  /// Returns true if all dependencies are correctly discovered. Inter-CU
+  /// dependencies cannot be discovered if referenced CU is not analyzed yet.
+  /// If that is the case this method returns false.
+  bool resolveDependenciesAndMarkLiveness(CompileUnit &CU);
+
+  /// Recursively walk the \p DIE tree and check "keepness" information.
+  /// It is an error if parent node does not have "keep" flag, while
+  /// child have one. This function dump error at stderr in that case.
+#ifndef NDEBUG
+  static void verifyKeepChain(CompileUnit &CU);
+#endif
+
+protected:
+  struct RootEntryTy {
+    RootEntryTy(CompileUnit &CU, const DWARFDebugInfoEntry *RootEntry)
+        : CU(CU), RootEntry(RootEntry) {}
+
+    // Compile unit keeping root entry.
+    CompileUnit &CU;
+
+    // Root entry.
+    const DWARFDebugInfoEntry *RootEntry;
+  };
+
+  using RootEntriesListTy = SmallVector<RootEntryTy>;
+
+  /// This function navigates DIEs tree starting from specified \p Entry.
+  /// It puts 'root DIE' into the worklist.
+  void collectRootsToKeep(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
+
+  /// Returns true if specified variable references live code section.
+  bool isLiveVariableEntry(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
+
+  /// Returns true if specified subprogram references live code section.
+  bool isLiveSubprogramEntry(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
+
+  /// Examine worklist and mark all 'root DIE's as kept.
+  bool markLiveRootsAsKept();
+
+  /// Mark whole DIE tree as kept recursively.
+  bool markDIEEntryAsKeptRec(const RootEntryTy &RootItem, CompileUnit &CU,
+                             const DWARFDebugInfoEntry *Entry);
+
+  /// Check referenced DIEs and add them into the worklist if neccessary.
+  bool maybeAddReferencedRoots(const RootEntryTy &RootItem, CompileUnit &CU,
+                               const DWARFDebugInfoEntry *Entry);
+
+  /// Add 'root DIE' into the worklist.
+  void addItemToWorklist(CompileUnit &CU, const DWARFDebugInfoEntry *Entry);
+
+  /// Set kind of placement(whether it goes into type table, plain dwarf or
+  /// both) for the specified die \p DieIdx.
+  void setDIEPlacementAndTypename(CompileUnit::DIEInfo &Info);
+
+  /// Flag indicating whether liveness information should be examined.
+  bool TrackLiveness = false;
+
+  /// List of CU, Entry pairs which are 'root DIE's.
+  RootEntriesListTy RootEntriesWorkList;
+
+  /// Link context for the analyzed CU.
+  DWARFLinkerImpl::LinkContext &Context;
+};
+
+} // end namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_DEPENDENCYTRACKER_H

diff  --git a/llvm/lib/DWARFLinkerParallel/IndexedValuesMap.h b/llvm/lib/DWARFLinkerParallel/IndexedValuesMap.h
new file mode 100644
index 00000000000000..0dc8de860a42e8
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/IndexedValuesMap.h
@@ -0,0 +1,49 @@
+//===- IndexedValuesMap.h ---------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_INDEXEDVALUESMAP_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_INDEXEDVALUESMAP_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include <cstdint>
+#include <utility>
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+template <typename T> class IndexedValuesMap {
+public:
+  uint64_t getValueIndex(T Value) {
+    typename ValueToIndexMapTy::iterator It = ValueToIndexMap.find(Value);
+    if (It == ValueToIndexMap.end()) {
+      It = ValueToIndexMap.insert(std::make_pair(Value, Values.size())).first;
+      Values.push_back(Value);
+    }
+    return It->second;
+  }
+
+  const SmallVector<T> &getValues() { return Values; }
+
+  void clear() {
+    ValueToIndexMap.clear();
+    Values.clear();
+  }
+
+  bool empty() { return Values.empty(); }
+
+protected:
+  using ValueToIndexMapTy = DenseMap<T, uint64_t>;
+  ValueToIndexMapTy ValueToIndexMap;
+  SmallVector<T> Values;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_INDEXEDVALUESMAP_H

diff  --git a/llvm/lib/DWARFLinkerParallel/OutputSections.cpp b/llvm/lib/DWARFLinkerParallel/OutputSections.cpp
index 69c5bfaa7bdf84..e623f4a54c5181 100644
--- a/llvm/lib/DWARFLinkerParallel/OutputSections.cpp
+++ b/llvm/lib/DWARFLinkerParallel/OutputSections.cpp
@@ -7,30 +7,393 @@
 //===----------------------------------------------------------------------===//
 
 #include "OutputSections.h"
+#include "DWARFLinkerCompileUnit.h"
 #include "llvm/ADT/StringSwitch.h"
 
 namespace llvm {
 namespace dwarflinker_parallel {
 
-std::optional<OutputSections::DebugSectionKind>
-OutputSections::parseDebugSectionName(llvm::StringRef SecName) {
-  return llvm::StringSwitch<std::optional<OutputSections::DebugSectionKind>>(
-             SecName)
-      .Case("debug_info", DebugSectionKind::DebugInfo)
-      .Case("debug_line", DebugSectionKind::DebugLine)
-      .Case("debug_frame", DebugSectionKind::DebugFrame)
-      .Case("debug_ranges", DebugSectionKind::DebugRange)
-      .Case("debug_rnglists", DebugSectionKind::DebugRngLists)
-      .Case("debug_loc", DebugSectionKind::DebugLoc)
-      .Case("debug_loclists", DebugSectionKind::DebugLocLists)
-      .Case("debug_aranges", DebugSectionKind::DebugARanges)
-      .Case("debug_abbrev", DebugSectionKind::DebugAbbrev)
-      .Case("debug_macinfo", DebugSectionKind::DebugMacinfo)
-      .Case("debug_macro", DebugSectionKind::DebugMacro)
+static constexpr StringLiteral SectionNames[SectionKindsNum] = {
+    "debug_info",     "debug_line",     "debug_frame",      "debug_ranges",
+    "debug_rnglists", "debug_loc",      "debug_loclists",   "debug_aranges",
+    "debug_abbrev",   "debug_macinfo",  "debug_macro",      "debug_addr",
+    "debug_str",      "debug_line_str", "debug_str_offsets"};
+
+const StringLiteral &getSectionName(DebugSectionKind SectionKind) {
+  return SectionNames[static_cast<uint8_t>(SectionKind)];
+}
+
+std::optional<DebugSectionKind> parseDebugTableName(llvm::StringRef SecName) {
+  return llvm::StringSwitch<std::optional<DebugSectionKind>>(
+             SecName.substr(SecName.find_first_not_of("._")))
+      .Case(getSectionName(DebugSectionKind::DebugInfo),
+            DebugSectionKind::DebugInfo)
+      .Case(getSectionName(DebugSectionKind::DebugLine),
+            DebugSectionKind::DebugLine)
+      .Case(getSectionName(DebugSectionKind::DebugFrame),
+            DebugSectionKind::DebugFrame)
+      .Case(getSectionName(DebugSectionKind::DebugRange),
+            DebugSectionKind::DebugRange)
+      .Case(getSectionName(DebugSectionKind::DebugRngLists),
+            DebugSectionKind::DebugRngLists)
+      .Case(getSectionName(DebugSectionKind::DebugLoc),
+            DebugSectionKind::DebugLoc)
+      .Case(getSectionName(DebugSectionKind::DebugLocLists),
+            DebugSectionKind::DebugLocLists)
+      .Case(getSectionName(DebugSectionKind::DebugARanges),
+            DebugSectionKind::DebugARanges)
+      .Case(getSectionName(DebugSectionKind::DebugAbbrev),
+            DebugSectionKind::DebugAbbrev)
+      .Case(getSectionName(DebugSectionKind::DebugMacinfo),
+            DebugSectionKind::DebugMacinfo)
+      .Case(getSectionName(DebugSectionKind::DebugMacro),
+            DebugSectionKind::DebugMacro)
+      .Case(getSectionName(DebugSectionKind::DebugAddr),
+            DebugSectionKind::DebugAddr)
+      .Case(getSectionName(DebugSectionKind::DebugStr),
+            DebugSectionKind::DebugStr)
+      .Case(getSectionName(DebugSectionKind::DebugLineStr),
+            DebugSectionKind::DebugLineStr)
+      .Case(getSectionName(DebugSectionKind::DebugStrOffsets),
+            DebugSectionKind::DebugStrOffsets)
       .Default(std::nullopt);
 
   return std::nullopt;
 }
 
+DebugDieRefPatch::DebugDieRefPatch(uint64_t PatchOffset, CompileUnit *SrcCU,
+                                   CompileUnit *RefCU, uint32_t RefIdx)
+    : SectionPatch({PatchOffset}),
+      RefCU(RefCU, (SrcCU != nullptr) &&
+                       (SrcCU->getUniqueID() == RefCU->getUniqueID())),
+      RefDieIdxOrClonedOffset(RefIdx) {}
+
+DebugULEB128DieRefPatch::DebugULEB128DieRefPatch(uint64_t PatchOffset,
+                                                 CompileUnit *SrcCU,
+                                                 CompileUnit *RefCU,
+                                                 uint32_t RefIdx)
+    : SectionPatch({PatchOffset}),
+      RefCU(RefCU, SrcCU->getUniqueID() == RefCU->getUniqueID()),
+      RefDieIdxOrClonedOffset(RefIdx) {}
+
+void SectionDescriptor::erase() {
+  StartOffset = 0;
+  Contents = OutSectionDataTy();
+  ListDebugStrPatch.erase();
+  ListDebugLineStrPatch.erase();
+  ListDebugRangePatch.erase();
+  ListDebugLocPatch.erase();
+  ListDebugDieRefPatch.erase();
+  ListDebugULEB128DieRefPatch.erase();
+  ListDebugOffsetPatch.erase();
+}
+
+void SectionDescriptor::setSizesForSectionCreatedByAsmPrinter() {
+  if (Contents.empty())
+    return;
+
+  MemoryBufferRef Mem(Contents, "obj");
+  Expected<std::unique_ptr<object::ObjectFile>> Obj =
+      object::ObjectFile::createObjectFile(Mem);
+  if (!Obj) {
+    consumeError(Obj.takeError());
+    Contents.clear();
+    return;
+  }
+
+  for (const object::SectionRef &Sect : (*Obj).get()->sections()) {
+    Expected<StringRef> SectNameOrErr = Sect.getName();
+    if (!SectNameOrErr) {
+      consumeError(SectNameOrErr.takeError());
+      continue;
+    }
+
+    if (std::optional<DebugSectionKind> SectKind =
+            parseDebugTableName(*SectNameOrErr)) {
+      if (*SectKind == SectionKind) {
+        Expected<StringRef> Data = Sect.getContents();
+        if (!Data) {
+          consumeError(SectNameOrErr.takeError());
+          Contents.clear();
+          return;
+        }
+
+        SectionOffsetInsideAsmPrinterOutputStart =
+            Data->data() - Contents.data();
+        SectionOffsetInsideAsmPrinterOutputEnd =
+            SectionOffsetInsideAsmPrinterOutputStart + Data->size();
+      }
+    }
+  }
+
+  return;
+}
+
+void SectionDescriptor::emitIntVal(uint64_t Val, unsigned Size) {
+  switch (Size) {
+  case 1: {
+    uint8_t ShortVal = static_cast<uint8_t>(Val);
+    OS.write(reinterpret_cast<const char *>(&ShortVal), Size);
+  } break;
+  case 2: {
+    uint16_t ShortVal = static_cast<uint16_t>(Val);
+    ShortVal = support::endian::byte_swap(ShortVal, getEndianess());
+    OS.write(reinterpret_cast<const char *>(&ShortVal), Size);
+  } break;
+  case 4: {
+    uint32_t ShortVal = static_cast<uint32_t>(Val);
+    ShortVal = support::endian::byte_swap(ShortVal, getEndianess());
+    OS.write(reinterpret_cast<const char *>(&ShortVal), Size);
+  } break;
+  case 8: {
+    uint64_t ShortVal = static_cast<uint64_t>(Val);
+    ShortVal = support::endian::byte_swap(ShortVal, getEndianess());
+    OS.write(reinterpret_cast<const char *>(&ShortVal), Size);
+  } break;
+  default:
+    llvm_unreachable("Unsupported integer type size");
+  }
+}
+
+void SectionDescriptor::emitString(dwarf::Form StringForm,
+                                   const char *StringVal) {
+  assert(StringVal != nullptr);
+
+  switch (StringForm) {
+  case dwarf::DW_FORM_string: {
+    emitInplaceString(GlobalData.translateString(StringVal));
+  } break;
+  case dwarf::DW_FORM_strp: {
+    notePatch(DebugStrPatch{
+        {OS.tell()}, GlobalData.getStringPool().insert(StringVal).first});
+    emitStringPlaceholder();
+  } break;
+  case dwarf::DW_FORM_line_strp: {
+    notePatch(DebugLineStrPatch{
+        {OS.tell()}, GlobalData.getStringPool().insert(StringVal).first});
+    emitStringPlaceholder();
+  } break;
+  default:
+    llvm_unreachable("Unsupported string form");
+    break;
+  };
+}
+
+void SectionDescriptor::apply(uint64_t PatchOffset, dwarf::Form AttrForm,
+                              uint64_t Val) {
+  switch (AttrForm) {
+  case dwarf::DW_FORM_strp:
+  case dwarf::DW_FORM_line_strp: {
+    applyIntVal(PatchOffset, Val, Format.getDwarfOffsetByteSize());
+  } break;
+
+  case dwarf::DW_FORM_ref_addr: {
+    applyIntVal(PatchOffset, Val, Format.getRefAddrByteSize());
+  } break;
+  case dwarf::DW_FORM_ref1: {
+    applyIntVal(PatchOffset, Val, 1);
+  } break;
+  case dwarf::DW_FORM_ref2: {
+    applyIntVal(PatchOffset, Val, 2);
+  } break;
+  case dwarf::DW_FORM_ref4: {
+    applyIntVal(PatchOffset, Val, 4);
+  } break;
+  case dwarf::DW_FORM_ref8: {
+    applyIntVal(PatchOffset, Val, 8);
+  } break;
+
+  case dwarf::DW_FORM_data1: {
+    applyIntVal(PatchOffset, Val, 1);
+  } break;
+  case dwarf::DW_FORM_data2: {
+    applyIntVal(PatchOffset, Val, 2);
+  } break;
+  case dwarf::DW_FORM_data4: {
+    applyIntVal(PatchOffset, Val, 4);
+  } break;
+  case dwarf::DW_FORM_data8: {
+    applyIntVal(PatchOffset, Val, 8);
+  } break;
+  case dwarf::DW_FORM_udata: {
+    applyULEB128(PatchOffset, Val);
+  } break;
+  case dwarf::DW_FORM_sdata: {
+    applySLEB128(PatchOffset, Val);
+  } break;
+  case dwarf::DW_FORM_sec_offset: {
+    applyIntVal(PatchOffset, Val, Format.getDwarfOffsetByteSize());
+  } break;
+  case dwarf::DW_FORM_flag: {
+    applyIntVal(PatchOffset, Val, 1);
+  } break;
+
+  default:
+    llvm_unreachable("Unsupported attribute form");
+    break;
+  }
+}
+
+uint64_t SectionDescriptor::getIntVal(uint64_t PatchOffset, unsigned Size) {
+  assert(PatchOffset < getContents().size());
+  switch (Size) {
+  case 1: {
+    return support::endian::read<uint8_t>(
+        const_cast<char *>(getContents().data() + PatchOffset), Endianess);
+  }
+  case 2: {
+    return support::endian::read<uint16_t>(
+        const_cast<char *>(getContents().data() + PatchOffset), Endianess);
+  }
+  case 4: {
+    return support::endian::read<uint32_t>(
+        const_cast<char *>(getContents().data() + PatchOffset), Endianess);
+  }
+  case 8: {
+    return support::endian::read<uint64_t>(
+        const_cast<char *>(getContents().data() + PatchOffset), Endianess);
+  }
+  }
+  llvm_unreachable("Unsupported integer type size");
+  return 0;
+}
+
+void SectionDescriptor::applyIntVal(uint64_t PatchOffset, uint64_t Val,
+                                    unsigned Size) {
+  assert(PatchOffset < getContents().size());
+
+  switch (Size) {
+  case 1: {
+    support::endian::write(
+        const_cast<char *>(getContents().data() + PatchOffset),
+        static_cast<uint8_t>(Val), Endianess);
+  } break;
+  case 2: {
+    support::endian::write(
+        const_cast<char *>(getContents().data() + PatchOffset),
+        static_cast<uint16_t>(Val), Endianess);
+  } break;
+  case 4: {
+    support::endian::write(
+        const_cast<char *>(getContents().data() + PatchOffset),
+        static_cast<uint32_t>(Val), Endianess);
+  } break;
+  case 8: {
+    support::endian::write(
+        const_cast<char *>(getContents().data() + PatchOffset),
+        static_cast<uint64_t>(Val), Endianess);
+  } break;
+  default:
+    llvm_unreachable("Unsupported integer type size");
+  }
+}
+
+void SectionDescriptor::applyULEB128(uint64_t PatchOffset, uint64_t Val) {
+  assert(PatchOffset < getContents().size());
+
+  uint8_t ULEB[16];
+  uint8_t DestSize = Format.getDwarfOffsetByteSize() + 1;
+  uint8_t RealSize = encodeULEB128(Val, ULEB, DestSize);
+
+  memcpy(const_cast<char *>(getContents().data() + PatchOffset), ULEB,
+         RealSize);
+}
+
+/// Writes integer value \p Val of SLEB128 format by specified \p PatchOffset.
+void SectionDescriptor::applySLEB128(uint64_t PatchOffset, uint64_t Val) {
+  assert(PatchOffset < getContents().size());
+
+  uint8_t SLEB[16];
+  uint8_t DestSize = Format.getDwarfOffsetByteSize() + 1;
+  uint8_t RealSize = encodeSLEB128(Val, SLEB, DestSize);
+
+  memcpy(const_cast<char *>(getContents().data() + PatchOffset), SLEB,
+         RealSize);
+}
+
+void OutputSections::applyPatches(
+    SectionDescriptor &Section,
+    StringEntryToDwarfStringPoolEntryMap &DebugStrStrings,
+    StringEntryToDwarfStringPoolEntryMap &DebugLineStrStrings) {
+
+  Section.ListDebugStrPatch.forEach([&](DebugStrPatch &Patch) {
+    DwarfStringPoolEntryWithExtString *Entry =
+        DebugStrStrings.getExistingEntry(Patch.String);
+    assert(Entry != nullptr);
+
+    Section.apply(Patch.PatchOffset, dwarf::DW_FORM_strp, Entry->Offset);
+  });
+
+  Section.ListDebugLineStrPatch.forEach([&](DebugLineStrPatch &Patch) {
+    DwarfStringPoolEntryWithExtString *Entry =
+        DebugLineStrStrings.getExistingEntry(Patch.String);
+    assert(Entry != nullptr);
+
+    Section.apply(Patch.PatchOffset, dwarf::DW_FORM_line_strp, Entry->Offset);
+  });
+
+  std::optional<SectionDescriptor *> RangeSection;
+  if (Format.Version >= 5)
+    RangeSection = getSectionDescriptor(DebugSectionKind::DebugRngLists);
+  else
+    RangeSection = getSectionDescriptor(DebugSectionKind::DebugRange);
+
+  if (RangeSection) {
+    Section.ListDebugRangePatch.forEach([&](DebugRangePatch &Patch) {
+      uint64_t FinalValue =
+          Section.getIntVal(Patch.PatchOffset, Format.getDwarfOffsetByteSize());
+      FinalValue += (*RangeSection)->StartOffset;
+
+      Section.apply(Patch.PatchOffset, dwarf::DW_FORM_sec_offset, FinalValue);
+    });
+  }
+
+  std::optional<SectionDescriptor *> LocationSection;
+  if (Format.Version >= 5)
+    LocationSection = getSectionDescriptor(DebugSectionKind::DebugLocLists);
+  else
+    LocationSection = getSectionDescriptor(DebugSectionKind::DebugLoc);
+
+  if (LocationSection) {
+    Section.ListDebugLocPatch.forEach([&](DebugLocPatch &Patch) {
+      uint64_t FinalValue =
+          Section.getIntVal(Patch.PatchOffset, Format.getDwarfOffsetByteSize());
+      FinalValue += (*LocationSection)->StartOffset;
+
+      Section.apply(Patch.PatchOffset, dwarf::DW_FORM_sec_offset, FinalValue);
+    });
+  }
+
+  Section.ListDebugDieRefPatch.forEach([&](DebugDieRefPatch &Patch) {
+    uint64_t FinalOffset = Patch.RefDieIdxOrClonedOffset;
+    dwarf::Form FinalForm = dwarf::DW_FORM_ref4;
+
+    if (!Patch.RefCU.getInt()) {
+      FinalForm = dwarf::DW_FORM_ref_addr;
+      FinalOffset +=
+          Patch.RefCU.getPointer()
+              ->getOrCreateSectionDescriptor(DebugSectionKind::DebugInfo)
+              .StartOffset;
+    }
+    Section.apply(Patch.PatchOffset, FinalForm, FinalOffset);
+  });
+
+  Section.ListDebugULEB128DieRefPatch.forEach(
+      [&](DebugULEB128DieRefPatch &Patch) {
+        assert(Patch.RefCU.getInt());
+        Section.apply(Patch.PatchOffset, dwarf::DW_FORM_udata,
+                      Patch.RefDieIdxOrClonedOffset);
+      });
+
+  Section.ListDebugOffsetPatch.forEach([&](DebugOffsetPatch &Patch) {
+    uint64_t FinalValue = Patch.SectionPtr.getPointer()->StartOffset;
+    if (Patch.SectionPtr.getInt())
+      FinalValue +=
+          Section.getIntVal(Patch.PatchOffset, Format.getDwarfOffsetByteSize());
+
+    Section.apply(Patch.PatchOffset, dwarf::DW_FORM_sec_offset, FinalValue);
+  });
+}
+
 } // end of namespace dwarflinker_parallel
 } // end of namespace llvm

diff  --git a/llvm/lib/DWARFLinkerParallel/OutputSections.h b/llvm/lib/DWARFLinkerParallel/OutputSections.h
index 15ab4cc1167a3c..00e00645a89e93 100644
--- a/llvm/lib/DWARFLinkerParallel/OutputSections.h
+++ b/llvm/lib/DWARFLinkerParallel/OutputSections.h
@@ -9,56 +9,397 @@
 #ifndef LLVM_LIB_DWARFLINKERPARALLEL_OUTPUTSECTIONS_H
 #define LLVM_LIB_DWARFLINKERPARALLEL_OUTPUTSECTIONS_H
 
+#include "ArrayList.h"
+#include "StringEntryToDwarfStringPoolEntryMap.h"
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/CodeGen/DwarfStringPoolEntry.h"
+#include "llvm/DWARFLinkerParallel/StringPool.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
+#include "llvm/DebugInfo/DWARF/DWARFObject.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/MemoryBufferRef.h"
+#include "llvm/Support/raw_ostream.h"
 #include <array>
 #include <cstdint>
 
 namespace llvm {
 namespace dwarflinker_parallel {
 
-/// This class keeps offsets to the debug sections. Any object which is
-/// supposed to be emitted into the debug section should use this class to
-/// track debug sections offsets.
-class OutputSections {
-public:
-  /// List of tracked debug sections.
-  enum class DebugSectionKind : uint8_t {
-    DebugInfo = 0,
-    DebugLine,
-    DebugFrame,
-    DebugRange,
-    DebugRngLists,
-    DebugLoc,
-    DebugLocLists,
-    DebugARanges,
-    DebugAbbrev,
-    DebugMacinfo,
-    DebugMacro,
-  };
-  constexpr static size_t SectionKindsNum = 11;
-
-  /// Recognise the section name and match it with the DebugSectionKind.
-  static std::optional<DebugSectionKind> parseDebugSectionName(StringRef Name);
+/// List of tracked debug tables.
+enum class DebugSectionKind : uint8_t {
+  DebugInfo = 0,
+  DebugLine,
+  DebugFrame,
+  DebugRange,
+  DebugRngLists,
+  DebugLoc,
+  DebugLocLists,
+  DebugARanges,
+  DebugAbbrev,
+  DebugMacinfo,
+  DebugMacro,
+  DebugAddr,
+  DebugStr,
+  DebugLineStr,
+  DebugStrOffsets,
+  NumberOfEnumEntries // must be last
+};
+constexpr static size_t SectionKindsNum =
+    static_cast<size_t>(DebugSectionKind::NumberOfEnumEntries);
+
+/// Recognise the table name and match it with the DebugSectionKind.
+std::optional<DebugSectionKind> parseDebugTableName(StringRef Name);
+
+/// Return the name of the section.
+const StringLiteral &getSectionName(DebugSectionKind SectionKind);
+
+/// There are fields(sizes, offsets) which should be updated after
+/// sections are generated. To remember offsets and related data
+/// the descendants of SectionPatch structure should be used.
+
+struct SectionPatch {
+  uint64_t PatchOffset = 0;
+};
+
+/// This structure is used to update strings offsets into .debug_str.
+struct DebugStrPatch : SectionPatch {
+  const StringEntry *String = nullptr;
+};
+
+/// This structure is used to update strings offsets into .debug_line_str.
+struct DebugLineStrPatch : SectionPatch {
+  const StringEntry *String = nullptr;
+};
+
+/// This structure is used to update range list offset into
+/// .debug_ranges/.debug_rnglists.
+struct DebugRangePatch : SectionPatch {
+  /// Indicates patch which points to immediate compile unit's attribute.
+  bool IsCompileUnitRanges = false;
+};
+
+/// This structure is used to update location list offset into
+/// .debug_loc/.debug_loclists.
+struct DebugLocPatch : SectionPatch {
+  int64_t AddrAdjustmentValue = 0;
+};
+
+/// This structure is used to update offset with start of another section.
+struct SectionDescriptor;
+struct DebugOffsetPatch : SectionPatch {
+  DebugOffsetPatch(uint64_t PatchOffset, SectionDescriptor *SectionPtr,
+                   bool AddLocalValue = false)
+      : SectionPatch({PatchOffset}), SectionPtr(SectionPtr, AddLocalValue) {}
+
+  PointerIntPair<SectionDescriptor *, 1> SectionPtr;
+};
+
+/// This structure is used to update reference to the DIE.
+struct DebugDieRefPatch : SectionPatch {
+  DebugDieRefPatch(uint64_t PatchOffset, CompileUnit *SrcCU, CompileUnit *RefCU,
+                   uint32_t RefIdx);
+
+  PointerIntPair<CompileUnit *, 1> RefCU;
+  uint64_t RefDieIdxOrClonedOffset;
+};
+
+/// This structure is used to update reference to the DIE of ULEB128 form.
+struct DebugULEB128DieRefPatch : SectionPatch {
+  DebugULEB128DieRefPatch(uint64_t PatchOffset, CompileUnit *SrcCU,
+                          CompileUnit *RefCU, uint32_t RefIdx);
+
+  PointerIntPair<CompileUnit *, 1> RefCU;
+  uint64_t RefDieIdxOrClonedOffset;
+};
+
+/// Type for section data.
+using OutSectionDataTy = SmallString<0>;
+
+/// Type for list of pointers to patches offsets.
+using OffsetsPtrVector = SmallVector<uint64_t *>;
+
+class OutputSections;
+
+/// This structure is used to keep data of the concrete section.
+/// Like data bits, list of patches, format.
+struct SectionDescriptor {
+  friend OutputSections;
+
+  SectionDescriptor(DebugSectionKind SectionKind, LinkingGlobalData &GlobalData,
+                    dwarf::FormParams Format, support::endianness Endianess)
+      : OS(Contents), GlobalData(GlobalData), SectionKind(SectionKind),
+        Format(Format), Endianess(Endianess) {
+    ListDebugStrPatch.setAllocator(&GlobalData.getAllocator());
+    ListDebugLineStrPatch.setAllocator(&GlobalData.getAllocator());
+    ListDebugRangePatch.setAllocator(&GlobalData.getAllocator());
+    ListDebugLocPatch.setAllocator(&GlobalData.getAllocator());
+    ListDebugDieRefPatch.setAllocator(&GlobalData.getAllocator());
+    ListDebugULEB128DieRefPatch.setAllocator(&GlobalData.getAllocator());
+    ListDebugOffsetPatch.setAllocator(&GlobalData.getAllocator());
+  }
+
+  /// Erase whole section contents(data bits, list of patches, format).
+  void erase();
 
   /// When objects(f.e. compile units) are glued into the single file,
   /// the debug sections corresponding to the concrete object are assigned
-  /// with offsets inside the whole file. This method returns offset
-  /// to the \p SectionKind debug section, corresponding to this object.
-  uint64_t getStartOffset(DebugSectionKind SectionKind) const {
-    return Offsets[static_cast<
-        typename std::underlying_type<DebugSectionKind>::type>(SectionKind)];
+  /// with offsets inside the whole file. This field keeps offset
+  /// to the debug section, corresponding to this object.
+  uint64_t StartOffset;
+
+  /// Stream which stores data to the Contents.
+  raw_svector_ostream OS;
+
+  /// Section patches.
+#define ADD_PATCHES_LIST(T)                                                    \
+  T &notePatch(const T &Patch) { return List##T.noteItem(Patch); }             \
+  ArrayList<T> List##T;
+
+  ADD_PATCHES_LIST(DebugStrPatch)
+  ADD_PATCHES_LIST(DebugLineStrPatch)
+  ADD_PATCHES_LIST(DebugRangePatch)
+  ADD_PATCHES_LIST(DebugLocPatch)
+  ADD_PATCHES_LIST(DebugDieRefPatch)
+  ADD_PATCHES_LIST(DebugULEB128DieRefPatch)
+  ADD_PATCHES_LIST(DebugOffsetPatch)
+
+  /// Offsets to some fields are not known at the moment of noting patch.
+  /// In that case we remember pointers to patch offset to update them later.
+  template <typename T>
+  void notePatchWithOffsetUpdate(const T &Patch,
+                                 OffsetsPtrVector &PatchesOffsetsList) {
+    PatchesOffsetsList.emplace_back(&notePatch(Patch).PatchOffset);
+  }
+
+  /// Some sections are emitted using AsmPrinter. In that case "Contents"
+  /// member of SectionDescriptor contains elf file. This method searches
+  /// for section data inside elf file and remember offset to it.
+  void setSizesForSectionCreatedByAsmPrinter();
+
+  /// Returns section content.
+  StringRef getContents() {
+    if (SectionOffsetInsideAsmPrinterOutputStart == 0)
+      return StringRef(Contents.data(), Contents.size());
+
+    return Contents.slice(SectionOffsetInsideAsmPrinterOutputStart,
+                          SectionOffsetInsideAsmPrinterOutputEnd);
+  }
+
+  /// Emit unit length into the current section contents.
+  void emitUnitLength(uint64_t Length) {
+    maybeEmitDwarf64Mark();
+    emitIntVal(Length, getFormParams().getDwarfOffsetByteSize());
+  }
+
+  /// Emit DWARF64 mark into the current section contents.
+  void maybeEmitDwarf64Mark() {
+    if (getFormParams().Format != dwarf::DWARF64)
+      return;
+    emitIntVal(dwarf::DW_LENGTH_DWARF64, 4);
+  }
+
+  /// Emit specified offset value into the current section contents.
+  void emitOffset(uint64_t Val) {
+    emitIntVal(Val, getFormParams().getDwarfOffsetByteSize());
+  }
+
+  /// Emit specified integer value into the current section contents.
+  void emitIntVal(uint64_t Val, unsigned Size);
+
+  /// Emit specified string value into the current section contents.
+  void emitString(dwarf::Form StringForm, const char *StringVal);
+
+  /// Emit specified inplace string value into the current section contents.
+  void emitInplaceString(StringRef String) {
+    OS << String;
+    emitIntVal(0, 1);
+  }
+
+  /// Emit string placeholder into the current section contents.
+  void emitStringPlaceholder() {
+    // emit bad offset which should be updated later.
+    emitOffset(0xBADDEF);
   }
 
-  /// Set offset to the start of specified \p SectionKind debug section,
-  /// corresponding to this object.
-  void setStartOffset(DebugSectionKind SectionKind, uint64_t Offset) {
-    Offsets[static_cast<typename std::underlying_type<DebugSectionKind>::type>(
-        SectionKind)] = Offset;
+  /// Write specified \p Value of \p AttrForm to the \p PatchOffset.
+  void apply(uint64_t PatchOffset, dwarf::Form AttrForm, uint64_t Val);
+
+  /// Returns section kind.
+  DebugSectionKind getKind() { return SectionKind; }
+
+  /// Returns section name.
+  const StringLiteral &getName() const { return getSectionName(SectionKind); }
+
+  /// Returns endianess used by section.
+  support::endianness getEndianess() const { return Endianess; };
+
+  /// Returns FormParams used by section.
+  dwarf::FormParams getFormParams() const { return Format; }
+
+  /// Returns integer value of \p Size located by specified \p PatchOffset.
+  uint64_t getIntVal(uint64_t PatchOffset, unsigned Size);
+
+protected:
+  /// Writes integer value \p Val of \p Size by specified \p PatchOffset.
+  void applyIntVal(uint64_t PatchOffset, uint64_t Val, unsigned Size);
+
+  /// Writes integer value \p Val of ULEB128 format by specified \p PatchOffset.
+  void applyULEB128(uint64_t PatchOffset, uint64_t Val);
+
+  /// Writes integer value \p Val of SLEB128 format by specified \p PatchOffset.
+  void applySLEB128(uint64_t PatchOffset, uint64_t Val);
+
+  /// Sets output format.
+  void setOutputFormat(dwarf::FormParams Format,
+                       support::endianness Endianess) {
+    this->Format = Format;
+    this->Endianess = Endianess;
+  }
+
+  LinkingGlobalData &GlobalData;
+
+  /// The section kind.
+  DebugSectionKind SectionKind;
+
+  /// Section data bits.
+  OutSectionDataTy Contents;
+
+  /// Some sections are generated using AsmPrinter. The real section data
+  /// located inside elf file in that case. Following fields points to the
+  /// real section content inside elf file.
+  size_t SectionOffsetInsideAsmPrinterOutputStart = 0;
+  size_t SectionOffsetInsideAsmPrinterOutputEnd = 0;
+
+  /// Output format.
+  dwarf::FormParams Format = {4, 4, dwarf::DWARF32};
+  support::endianness Endianess = support::endianness::little;
+};
+
+/// This class keeps contents and offsets to the debug sections. Any objects
+/// which is supposed to be emitted into the debug sections should use this
+/// class to track debug sections offsets and keep sections data.
+class OutputSections {
+public:
+  OutputSections(LinkingGlobalData &GlobalData) : GlobalData(GlobalData) {}
+
+  /// Sets output format for all keeping sections.
+  void setOutputFormat(DWARFUnit &OriginalUnit) {
+    setOutputFormat(OriginalUnit.getFormParams(),
+                    OriginalUnit.isLittleEndian() ? support::endianness::little
+                                                  : support::endianness::big);
+  }
+
+  /// Sets output format for all keeping sections.
+  void setOutputFormat(dwarf::FormParams Format,
+                       support::endianness Endianess) {
+    this->Format = Format;
+    this->Endianess = Endianess;
+  }
+
+  /// Returns descriptor for the specified section of \p SectionKind.
+  std::optional<const SectionDescriptor *>
+  getSectionDescriptor(DebugSectionKind SectionKind) const {
+    SectionsSetTy::const_iterator It = SectionDescriptors.find(SectionKind);
+
+    if (It == SectionDescriptors.end())
+      return std::nullopt;
+
+    return &It->second;
+  }
+
+  /// Returns descriptor for the specified section of \p SectionKind.
+  std::optional<SectionDescriptor *>
+  getSectionDescriptor(DebugSectionKind SectionKind) {
+    SectionsSetTy::iterator It = SectionDescriptors.find(SectionKind);
+
+    if (It == SectionDescriptors.end())
+      return std::nullopt;
+
+    return &It->second;
+  }
+
+  /// Returns descriptor for the specified section of \p SectionKind.
+  /// If descriptor does not exist then create it.
+  SectionDescriptor &
+  getOrCreateSectionDescriptor(DebugSectionKind SectionKind) {
+    return SectionDescriptors
+        .try_emplace(SectionKind, SectionKind, GlobalData, Format, Endianess)
+        .first->second;
+  }
+
+  /// Erases data of all sections.
+  void eraseSections() {
+    for (auto &Section : SectionDescriptors)
+      Section.second.erase();
+  }
+
+  /// Enumerate all sections and call \p Handler for each.
+  void forEach(function_ref<void(SectionDescriptor &)> Handler) {
+    for (auto &Section : SectionDescriptors)
+      Handler(Section.second);
+  }
+
+  /// Enumerate all sections, for each section set current offset
+  /// (kept by \p SectionSizesAccumulator), update current offset with section
+  /// length.
+  void assignSectionsOffsetAndAccumulateSize(
+      std::array<uint64_t, SectionKindsNum> &SectionSizesAccumulator) {
+    for (auto &Section : SectionDescriptors) {
+      Section.second.StartOffset = SectionSizesAccumulator[static_cast<uint8_t>(
+          Section.second.getKind())];
+      SectionSizesAccumulator[static_cast<uint8_t>(Section.second.getKind())] +=
+          Section.second.getContents().size();
+    }
   }
 
+  /// Enumerate all sections, for each section apply all section patches.
+  void applyPatches(SectionDescriptor &Section,
+                    StringEntryToDwarfStringPoolEntryMap &DebugStrStrings,
+                    StringEntryToDwarfStringPoolEntryMap &DebugLineStrStrings);
+
+  /// Endiannes for the sections.
+  support::endianness getEndianness() const { return Endianess; }
+
+  /// Return DWARF version.
+  uint16_t getVersion() const { return Format.Version; }
+
+  /// Return size of header of debug_info table.
+  uint16_t getDebugInfoHeaderSize() const {
+    return Format.Version >= 5 ? 12 : 11;
+  }
+
+  /// Return size of header of debug_ table.
+  uint16_t getDebugAddrHeaderSize() const {
+    assert(Format.Version >= 5);
+    return Format.Format == dwarf::DwarfFormat::DWARF32 ? 8 : 16;
+  }
+
+  /// Return size of header of debug_str_offsets table.
+  uint16_t getDebugStrOffsetsHeaderSize() const {
+    assert(Format.Version >= 5);
+    return Format.Format == dwarf::DwarfFormat::DWARF32 ? 8 : 16;
+  }
+
+  /// Return size of address.
+  const dwarf::FormParams &getFormParams() const { return Format; }
+
 protected:
-  /// Offsets to the debug sections composing this object.
-  std::array<uint64_t, SectionKindsNum> Offsets = {0};
+  LinkingGlobalData &GlobalData;
+
+  /// Format for sections.
+  dwarf::FormParams Format = {4, 4, dwarf::DWARF32};
+
+  /// Endiannes for sections.
+  support::endianness Endianess = support::endianness::little;
+
+  /// All keeping sections.
+  using SectionsSetTy = std::map<DebugSectionKind, SectionDescriptor>;
+  SectionsSetTy SectionDescriptors;
 };
 
 } // end of namespace dwarflinker_parallel

diff  --git a/llvm/lib/DWARFLinkerParallel/StringEntryToDwarfStringPoolEntryMap.h b/llvm/lib/DWARFLinkerParallel/StringEntryToDwarfStringPoolEntryMap.h
new file mode 100644
index 00000000000000..b4c74d0adba970
--- /dev/null
+++ b/llvm/lib/DWARFLinkerParallel/StringEntryToDwarfStringPoolEntryMap.h
@@ -0,0 +1,72 @@
+//===- StringEntryToDwarfStringPoolEntryMap.h -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_DWARFLINKERPARALLEL_STRINGENTRYTODWARFSTRINGPOOLENTRYMAP_H
+#define LLVM_LIB_DWARFLINKERPARALLEL_STRINGENTRYTODWARFSTRINGPOOLENTRYMAP_H
+
+#include "DWARFLinkerGlobalData.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/DWARFLinkerParallel/StringPool.h"
+
+namespace llvm {
+namespace dwarflinker_parallel {
+
+/// This class creates a DwarfStringPoolEntry for the corresponding StringEntry.
+class StringEntryToDwarfStringPoolEntryMap {
+public:
+  StringEntryToDwarfStringPoolEntryMap(LinkingGlobalData &GlobalData)
+      : GlobalData(GlobalData) {}
+  ~StringEntryToDwarfStringPoolEntryMap() {}
+
+  /// Create DwarfStringPoolEntry for specified StringEntry if necessary.
+  /// Initialize DwarfStringPoolEntry with initial values.
+  DwarfStringPoolEntryWithExtString *add(const StringEntry *String) {
+    DwarfStringPoolEntriesTy::iterator it = DwarfStringPoolEntries.find(String);
+
+    if (it == DwarfStringPoolEntries.end()) {
+      DwarfStringPoolEntryWithExtString *DataPtr =
+          GlobalData.getAllocator()
+              .Allocate<DwarfStringPoolEntryWithExtString>();
+      DataPtr->String = GlobalData.translateString(String->getKey());
+      DataPtr->Index = DwarfStringPoolEntry::NotIndexed;
+      DataPtr->Offset = 0;
+      DataPtr->Symbol = nullptr;
+      it = DwarfStringPoolEntries.insert(std::make_pair(String, DataPtr)).first;
+    }
+
+    assert(it->second != nullptr);
+    return it->second;
+  }
+
+  /// Returns already existed DwarfStringPoolEntry for the specified
+  /// StringEntry.
+  DwarfStringPoolEntryWithExtString *
+  getExistingEntry(const StringEntry *String) const {
+    DwarfStringPoolEntriesTy::const_iterator it =
+        DwarfStringPoolEntries.find(String);
+
+    assert(it != DwarfStringPoolEntries.end());
+    assert(it->second != nullptr);
+    return it->second;
+  }
+
+  /// Erase contents of StringsForEmission.
+  void clear() { DwarfStringPoolEntries.clear(); }
+
+protected:
+  using DwarfStringPoolEntriesTy =
+      DenseMap<const StringEntry *, DwarfStringPoolEntryWithExtString *>;
+  DwarfStringPoolEntriesTy DwarfStringPoolEntries;
+
+  LinkingGlobalData &GlobalData;
+};
+
+} // end of namespace dwarflinker_parallel
+} // end namespace llvm
+
+#endif // LLVM_LIB_DWARFLINKERPARALLEL_STRINGENTRYTODWARFSTRINGPOOLENTRYMAP_H

diff  --git a/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-dwarf4-combination-macho.test b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-dwarf4-combination-macho.test
new file mode 100644
index 00000000000000..96febc4fb1b870
--- /dev/null
+++ b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-dwarf4-combination-macho.test
@@ -0,0 +1,200 @@
+; This test checks to ensure that if a DWARF v5 and DWARF v4 object file is used to
+; generate a dsym, dsymutil correctly outputs the debug information, by keeping
+; the DWARF v5 and DWARF v4 debug info distinct, and that all the section headers
+; have the correct format.
+
+; 1.o was produced with the source file:
+
+; a.cpp
+; __attribute__((section("1,__text_foo"))) void foo() {}
+;
+; int foo2(int a) {
+;     return a+5;
+; }
+; int main () {
+;     return 1;
+; }
+
+; clang -g -c -O1 a.cpp -Xclang -gdwarf-5 -o 1.o
+
+; 2.o was produced with the following source file:
+
+; b.cpp
+; __attribute__((section("1,__text_foo2"))) void foo2() {}
+;
+; int bar(int x) {
+;     int y = x + 2;
+;     return y;
+; }
+
+; clang -g -c -O1 b.cpp -gdwarf-4 -o 2.o
+
+
+RUN: rm -rf %t.dir && mkdir -p %t.dir
+RUN: dsymutil --linker llvm -y %p/../dummy-debug-map-amr64.map \
+RUN:   -oso-prepend-path=%p/../../Inputs/DWARF5-DWARF4-combination \
+RUN:   -o %t.dir/dwarf5-dwarf4-combination-macho.dSYM
+RUN: llvm-dwarfdump %t.dir/dwarf5-dwarf4-combination-macho.dSYM -a --verbose | FileCheck %s
+
+
+CHECK:.debug_abbrev contents:
+CHECK-NEXT: Abbrev table for offset: 0x00000000
+
+CHECK: .debug_info contents:
+CHECK: 0x00000000: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 
+CHECK: DW_AT_producer [DW_FORM_strx]     (indexed (00000000) string = "Apple clang version 14.0.3 (clang-1403.0.22.14.1)")
+CHECK: DW_AT_name [DW_FORM_strx] (indexed (00000001) string = "a.cpp")
+CHECK: DW_AT_LLVM_sysroot [DW_FORM_strx] (indexed (00000002) string = "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk")
+CHECK: DW_AT_APPLE_sdk [DW_FORM_strx]    (indexed (00000003) string = "MacOSX.sdk")
+CHECK: DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x00000008)
+CHECK: DW_AT_comp_dir [DW_FORM_strx]     (indexed (00000004) string = "/Users/shubham/Development/test109275485")
+CHECK: DW_AT_ranges [DW_FORM_sec_offset] (0x[[RANGELIST_OFFSET:[0-9a-f]+]]
+CHECK-NEXT:                  [0x[[RANGELIST_OFFSET_START:[0-9a-f]+]], 0x[[RANGELIST_OFFSET_END:[0-9a-f]+]]))
+CHECK-NEXT: DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000008)
+CHECK: 0x0000002c:   DW_TAG_subprogram [2] * (0x0000000c)
+CHECK-NEXT:  DW_AT_low_pc [DW_FORM_addrx]     (indexed (00000000) address = 0x[[#%.16x,LOCLIST_LOWPC:]])
+CHECK: DW_AT_linkage_name [DW_FORM_strx]       (indexed (00000005) string = "_Z4foo2i")
+CHECK: DW_AT_name [DW_FORM_strx]       (indexed (00000006) string = "foo2")
+CHECK: 0x0000003c:     DW_TAG_formal_parameter [3]   (0x0000002c)
+CHECK-NEXT:                   DW_AT_location [DW_FORM_sec_offset]   (0x[[LOCLIST_OFFSET:[0-9a-f]+]]: 
+CHECK-NEXT:                      [0x[[#%.16x,LOCLIST_PAIR_START:]], 0x[[#%.16x,LOCLIST_PAIR_END:]]): [[LOCLIST_EXPR:.*]]
+CHECK-NEXT:                      [0x[[#%.16x,LOCLIST_PAIR_START2:]], 0x[[#%.16x,LOCLIST_PAIR_END2:]]): [[LOCLIST_EXPR2:.*]])
+CHECK: DW_AT_name [DW_FORM_strx]     (indexed (00000007) string = "a")
+
+CHECK: 0x0000004e: Compile Unit: length = 0x00000072, format = DWARF32, version = 0x0004, abbr_offset = 0x005a, addr_size = 0x08 
+CHECK: DW_AT_producer [DW_FORM_strp]     ( .debug_str[0x00000001] = "Apple clang version 14.0.3 (clang-1403.0.22.14.1)")
+CHECK: DW_AT_name [DW_FORM_strp] ( .debug_str[0x000000e0] = "b.cpp")
+CHECK: DW_AT_LLVM_sysroot [DW_FORM_strp] ( .debug_str[0x00000039] = "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk")
+CHECK: DW_AT_APPLE_sdk [DW_FORM_strp]    ( .debug_str[0x00000098] = "MacOSX.sdk")
+CHECK-NOT: DW_AT_str_offsets_base
+CHECK: DW_AT_comp_dir [DW_FORM_strp]     ( .debug_str[0x000000a3] = "/Users/shubham/Development/test109275485")
+CHECK:              DW_AT_low_pc [DW_FORM_addr]       (0x[[#%.16x,RANGE_LOWPC:]])
+CHECK-NEXT:              DW_AT_ranges [DW_FORM_sec_offset] (0x00000000
+CHECK-NEXT:                 [0x[[#%.16x,RANGE_START:]], 0x[[#%.16x,RANGE_END:]]))
+CHECK: 0x00000080:   DW_TAG_subprogram {{.*}} * (0x00000059)
+CHECK-NEXT:                DW_AT_low_pc [DW_FORM_addr]     (0x[[#%.16x,LOC_LOWPC:]])
+CHECK: DW_AT_linkage_name [DW_FORM_strp]       ( .debug_str[0x000000e6] = "_Z3bari")
+CHECK: DW_AT_name [DW_FORM_strp]       ( .debug_str[0x000000ee] = "bar")
+CHECK: 0x0000009d:     DW_TAG_formal_parameter {{.*}}   (0x00000080)
+CHECK-NEXT:                  DW_AT_location [DW_FORM_sec_offset]   (0x[[LOC_OFFSET:[0-9a-f]+]]: 
+CHECK-NEXT:                     [0x[[#%.16x,LOC_PAIR_START:]], 0x[[#%.16x,LOC_PAIR_END:]]): [[LOC_EXPR:.*]]
+CHECK-NEXT:                     [0x[[#%.16x,LOC_PAIR_START2:]], 0x[[#%.16x,LOC_PAIR_END2:]]): [[LOC_EXPR2:.*]])
+CHECK: DW_AT_name [DW_FORM_strp]     ( .debug_str[0x000000f2] = "x")
+
+CHECK: .debug_loc contents:
+CHECK-NEXT: 0x[[LOC_OFFSET]]:
+CHECK-NEXT:            (0x[[#sub(LOC_PAIR_START,LOC_LOWPC)]], 0x[[#sub(LOC_PAIR_END,LOC_LOWPC)]]): [[LOC_EXPR:.*]]
+CHECK-NEXT:            (0x[[#sub(LOC_PAIR_START2,LOC_LOWPC)]], 0x[[#sub(LOC_PAIR_END2,LOC_LOWPC)]]): [[LOC_EXPR2:.*]]
+
+CHECK: .debug_loclists contents:
+CHECK-NEXT: 0x00000000: locations list header: length = 0x00000018, format = DWARF32, version = 0x0005, addr_size = 0x08, seg_size = 0x00, offset_entry_count = 0x00000000
+CHECK-NEXT: 0x[[LOCLIST_OFFSET]]: 
+CHECK-NEXT:            DW_LLE_base_addressx   (0x0000000000000000)
+CHECK-NEXT:            DW_LLE_offset_pair     (0x[[#sub(LOCLIST_PAIR_START,LOCLIST_LOWPC)]], 0x[[#sub(LOCLIST_PAIR_END,LOCLIST_LOWPC)]])
+CHECK-NEXT:            DW_LLE_offset_pair     (0x[[#sub(LOCLIST_PAIR_START2,LOCLIST_LOWPC)]], 0x[[#sub(LOCLIST_PAIR_END2,LOCLIST_LOWPC)]])
+CHECK-NEXT:            DW_LLE_end_of_list     ()
+
+CHECK: .debug_line contents:
+CHECK-NEXT: debug_line[0x00000000]
+CHECK-NEXT: Line table prologue:
+CHECK-NEXT:     total_length: 0x00000048
+CHECK-NEXT:           format: DWARF32
+CHECK-NEXT:          version: 5
+CHECK-NEXT:     address_size: 8
+CHECK-NEXT:  seg_select_size: 0
+CHECK-NEXT:  prologue_length: 0x00000025
+CHECK-NEXT:  min_inst_length: 1
+CHECK-NEXT: max_ops_per_inst: 1
+CHECK-NEXT:  default_is_stmt: 1
+CHECK-NEXT:        line_base: -5
+CHECK-NEXT:       line_range: 14
+CHECK-NEXT:      opcode_base: 13
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_copy] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_advance_pc] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_advance_line] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_file] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_column] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_negate_stmt] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_basic_block] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_const_add_pc] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_fixed_advance_pc] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_prologue_end] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_epilogue_begin] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_isa] = 1
+CHECK-NEXT: include_directories[  0] =  .debug_line_str[0x00000000] = "/Users/shubham/Development/test109275485"
+CHECK-NEXT: file_names[  0]:
+CHECK-NEXT:            name:  .debug_line_str[0x00000029] = "a.cpp"
+CHECK-NEXT:       dir_index: 0
+
+CHECK: debug_line[0x0000004c]
+CHECK-NEXT: Line table prologue:
+CHECK-NEXT:     total_length: 0x0000003b
+CHECK-NEXT:           format: DWARF32
+CHECK-NEXT:          version: 4
+CHECK-NEXT:  prologue_length: 0x0000001d
+CHECK-NEXT:  min_inst_length: 1
+CHECK-NEXT: max_ops_per_inst: 1
+CHECK-NEXT:  default_is_stmt: 1
+CHECK-NEXT:        line_base: -5
+CHECK-NEXT:       line_range: 14
+CHECK-NEXT:      opcode_base: 13
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_copy] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_advance_pc] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_advance_line] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_file] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_column] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_negate_stmt] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_basic_block] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_const_add_pc] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_fixed_advance_pc] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_prologue_end] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_epilogue_begin] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_isa] = 1
+CHECK-NEXT: file_names[  1]:
+CHECK-NEXT:            name: "b.cpp"
+CHECK-NEXT:       dir_index: 0
+CHECK-NEXT:        mod_time: 0x00000000
+CHECK-NEXT:          length: 0x00000000
+
+CHECK: .debug_str contents:
+CHECK-NEXT: 0x00000000: ""
+CHECK-NEXT: 0x00000001: "Apple clang version 14.0.3 (clang-1403.0.22.14.1)"
+CHECK-NEXT: 0x00000033: "a.cpp"
+CHECK-NEXT: 0x00000039: "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk"
+CHECK-NEXT: 0x00000098: "MacOSX.sdk"
+CHECK-NEXT: 0x000000a3: "/Users/shubham/Development/test109275485"
+CHECK-NEXT: 0x000000cc: "_Z4foo2i"
+CHECK-NEXT: 0x000000d5: "foo2"
+CHECK-NEXT: 0x000000da: "a"
+CHECK-NEXT: 0x000000dc: "int"
+CHECK-NEXT: 0x000000e0: "b.cpp"
+CHECK-NEXT: 0x000000e6: "_Z3bari"
+CHECK-NEXT: 0x000000ee: "bar"
+CHECK-NEXT: 0x000000f2: "x"
+CHECK-NEXT: 0x000000f4: "y"
+
+CHECK: .debug_line_str contents:
+CHECK-NEXT: 0x00000000: "/Users/shubham/Development/test109275485"
+CHECK-NEXT: 0x00000029: "a.cpp"
+
+CHECK: .debug_ranges contents:
+CHECK-NEXT: 00000000 [[#sub(RANGE_START,RANGE_LOWPC)]] [[#sub(RANGE_END,RANGE_LOWPC)]]
+
+CHECK: .debug_rnglists contents:
+CHECK-NEXT: 0x00000000: range list header: length = 0x0000000e, format = DWARF32, version = 0x0005, addr_size = 0x08, seg_size = 0x00, offset_entry_count = 0x00000000
+CHECK-NEXT: ranges:
+CHECK-NEXT: [[RANGELIST_OFFSET]]: [DW_RLE_base_addressx]:  0x0000000000000000
+CHECK-NEXT: 0x0000000e: [DW_RLE_offset_pair  ]: {{.*}}[0x[[RANGELIST_OFFSET_START]], 0x[[RANGELIST_OFFSET_END]])
+CHECK-NEXT: 0x00000011: [DW_RLE_end_of_list  ]
+
+CHECK: .debug_str_offsets contents:
+CHECK-NEXT: 0x00000000: Contribution size = 40, Format = DWARF32, Version = 5
+CHECK-NEXT: 0x00000008: 00000001 "Apple clang version 14.0.3 (clang-1403.0.22.14.1)"
+CHECK-NEXT: 0x0000000c: 00000033 "a.cpp"
+CHECK-NEXT: 0x00000010: 00000039 "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk"
+CHECK-NEXT: 0x00000014: 00000098 "MacOSX.sdk"
+CHECK-NEXT: 0x00000018: 000000a3 "/Users/shubham/Development/test109275485"
+CHECK-NEXT: 0x0000001c: 000000cc "_Z4foo2i"
+CHECK-NEXT: 0x00000020: 000000d5 "foo2"
+CHECK-NEXT: 0x00000024: 000000da "a"
+CHECK-NEXT: 0x00000028: 000000dc "int"

diff  --git a/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-macho.test b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-macho.test
new file mode 100644
index 00000000000000..0e1e427be67c2c
--- /dev/null
+++ b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/dwarf5-macho.test
@@ -0,0 +1,92 @@
+; This test checks to that DWARF v5 debug info can be correctly linked
+; into a dSYM bundle by dsymutil, with the correct section names and DWARF v5
+; headers for the 
diff erent sections.
+
+; 1.o was produced with the source file:
+
+; a.cpp
+; __attribute__((section("1,__text_foo"))) void foo() {}
+;
+; int foo2(int a) {
+;     return a+5;
+; }
+; int main () {
+;     return 1;
+; }
+
+; clang -g -c -O1 a.cpp -Xclang -gdwarf-5 -o 1.o
+
+
+RUN: rm -rf %t.dir && mkdir -p %t.dir
+RUN: dsymutil --linker llvm -y %p/../dummy-debug-map-amr64.map \
+RUN:   -oso-prepend-path=%p/../../Inputs/DWARF5 -o %t.dir/dwarf5-macho.dSYM
+RUN: llvm-dwarfdump %t.dir/dwarf5-macho.dSYM -a --verbose | FileCheck %s
+
+CHECK:.debug_abbrev contents:
+CHECK-NEXT: Abbrev table for offset: 0x00000000
+
+CHECK: .debug_info contents:
+CHECK-NEXT: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 
+CHECK: DW_AT_ranges [DW_FORM_sec_offset] (0x[[RANGELIST_OFFSET:[0-9a-f]+]]
+CHECK-NEXT:                  [0x[[RANGELIST_OFFSET_START:[0-9a-f]+]], 0x[[RANGELIST_OFFSET_END:[0-9a-f]+]]))
+CHECK-NEXT: DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000008)
+CHECK: 0x0000002c:   DW_TAG_subprogram [2] * (0x0000000c)
+CHECK-NEXT:  DW_AT_low_pc [DW_FORM_addrx]     (indexed (00000000) address = 0x[[#%.16x,LOCLIST_LOWPC:]])
+CHECK: 0x0000003c:     DW_TAG_formal_parameter [3]   (0x0000002c)
+CHECK-NEXT:                   DW_AT_location [DW_FORM_sec_offset]   (0x[[LOC_OFFSET:[0-9a-f]+]]: 
+CHECK-NEXT:                      [0x[[#%.16x,LOCLIST_PAIR_START:]], 0x[[#%.16x,LOCLIST_PAIR_END:]]): [[LOCLIST_EXPR:.*]]
+CHECK-NEXT:                      [0x[[#%.16x,LOCLIST_PAIR_START2:]], 0x[[#%.16x,LOCLIST_PAIR_END2:]]): [[LOCLIST_EXPR2:.*]])
+
+CHECK: .debug_loclists contents:
+CHECK-NEXT: 0x00000000: locations list header: length = 0x00000018, format = DWARF32, version = 0x0005, addr_size = 0x08, seg_size = 0x00, offset_entry_count = 0x00000000
+CHECK-NEXT: 0x[[LOC_OFFSET]]: 
+CHECK-NEXT:            DW_LLE_base_addressx   (0x0000000000000000)
+CHECK-NEXT:            DW_LLE_offset_pair     (0x[[#sub(LOCLIST_PAIR_START,LOCLIST_LOWPC)]], 0x[[#sub(LOCLIST_PAIR_END,LOCLIST_LOWPC)]])
+CHECK-NEXT:            DW_LLE_offset_pair     (0x[[#sub(LOCLIST_PAIR_START2,LOCLIST_LOWPC)]], 0x[[#sub(LOCLIST_PAIR_END2,LOCLIST_LOWPC)]])
+CHECK-NEXT:            DW_LLE_end_of_list     ()
+
+CHECK: .debug_line contents:
+CHECK-NEXT: debug_line[0x00000000]
+CHECK-NEXT: Line table prologue:
+CHECK-NEXT:     total_length: 0x00000048
+CHECK-NEXT:           format: DWARF32
+CHECK-NEXT:          version: 5
+CHECK-NEXT:     address_size: 8
+CHECK-NEXT:  seg_select_size: 0
+CHECK-NEXT:  prologue_length: 0x00000025
+CHECK-NEXT:  min_inst_length: 1
+CHECK-NEXT: max_ops_per_inst: 1
+CHECK-NEXT:  default_is_stmt: 1
+CHECK-NEXT:        line_base: -5
+CHECK-NEXT:       line_range: 14
+CHECK-NEXT:      opcode_base: 13
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_copy] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_advance_pc] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_advance_line] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_file] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_column] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_negate_stmt] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_basic_block] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_const_add_pc] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_fixed_advance_pc] = 1
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_prologue_end] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_epilogue_begin] = 0
+CHECK-NEXT: standard_opcode_lengths[DW_LNS_set_isa] = 1
+CHECK-NEXT: include_directories[  0] =  .debug_line_str[0x00000000] = "/Users/shubham/Development/test109275485"
+CHECK-NEXT: file_names[  0]:
+CHECK-NEXT:            name:  .debug_line_str[0x00000029] = "a.cpp"
+CHECK-NEXT:       dir_index: 0
+
+
+CHECK: .debug_str contents:
+
+CHECK: .debug_line_str contents:
+CHECK-NEXT: 0x00000000: "/Users/shubham/Development/test109275485"
+CHECK-NEXT: 0x00000029: "a.cpp"
+
+CHECK: .debug_rnglists contents:
+CHECK-NEXT: 0x00000000: range list header: length = 0x0000000e, format = DWARF32, version = 0x0005, addr_size = 0x08, seg_size = 0x00, offset_entry_count = 0x00000000
+CHECK-NEXT: ranges:
+CHECK-NEXT: [[RANGELIST_OFFSET]]: [DW_RLE_base_addressx]:  0x0000000000000000
+CHECK-NEXT: 0x0000000e: [DW_RLE_offset_pair  ]: {{.*}}[0x[[RANGELIST_OFFSET_START]], 0x[[RANGELIST_OFFSET_END]])
+CHECK-NEXT: 0x00000011: [DW_RLE_end_of_list  ]

diff  --git a/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/fat-dylib-update.test b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/fat-dylib-update.test
new file mode 100644
index 00000000000000..4947f6005d3fe5
--- /dev/null
+++ b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/fat-dylib-update.test
@@ -0,0 +1,110 @@
+# REQUIRES: object-emission,system-darwin
+# RUN: dsymutil --linker llvm -oso-prepend-path %p/../..  %p/../../Inputs/fat-test.arm.dylib -o %t.dSYM
+# RUN: llvm-dwarfdump -a -v %t.dSYM/Contents/Resources/DWARF/fat-test.arm.dylib | FileCheck %s
+# RUN: dsymutil --linker llvm -u %t.dSYM
+# RUN: llvm-dwarfdump -a -v %t.dSYM/Contents/Resources/DWARF/fat-test.arm.dylib | FileCheck %s
+# RUN: dsymutil --linker llvm -u %t.dSYM -o %t1.dSYM
+# RUN: llvm-dwarfdump -a -v %t1.dSYM/Contents/Resources/DWARF/fat-test.arm.dylib | FileCheck %s
+
+CHECK: /Contents/Resources/DWARF/fat-test.arm.dylib(armv7):	file format Mach-O arm
+
+CHECK: .debug_info contents:
+CHECK:  Compile Unit: length = 0x00000034, format = DWARF32, version = 0x0002, abbr_offset = 0x0000, addr_size = 0x04 (next unit at 0x00000038)
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]	( .debug_str[0x00000001] = "clang version 3.8.0 (trunk 243776)")
+CHECK:    DW_AT_language [DW_FORM_data2]	(DW_LANG_C99)
+CHECK:    DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000024] = "fat-test.c")
+CHECK:    DW_AT_stmt_list [DW_FORM_data4]	(0x00000000)
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]	( .debug_str[0x0000002f] = "/Inputs")
+CHECK:    DW_TAG_variable [2]
+CHECK:      DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000037] = "armv7_var")
+CHECK:      DW_AT_type [DW_FORM_ref4]	(cu + 0x0030 => {0x00000030}
+CHECK:      DW_AT_external [DW_FORM_flag]	(0x01)
+CHECK:      DW_AT_decl_file [DW_FORM_data1]	("/Inputs/fat-test.c")
+CHECK:      DW_AT_decl_line [DW_FORM_data1]	(23)
+CHECK:      DW_AT_location [DW_FORM_block1]	(DW_OP_addr 0x1000)
+CHECK:    DW_TAG_base_type [3]
+CHECK:      DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000041] = "int")
+CHECK:      DW_AT_encoding [DW_FORM_data1]	(DW_ATE_signed)
+CHECK:      DW_AT_byte_size [DW_FORM_data1]	(0x04)
+CHECK:    NULL
+
+
+CHECK: .debug_line contents:
+CHECK: Line table prologue:
+CHECK:     total_length: 0x0000002a
+CHECK:          version: 2
+CHECK:  prologue_length: 0x00000021
+CHECK:  min_inst_length: 1
+CHECK:  default_is_stmt: 1
+CHECK:        line_base: -5
+CHECK:       line_range: 14
+CHECK:      opcode_base: 13
+
+CHECK: /Contents/Resources/DWARF/fat-test.arm.dylib(armv7s):	file format Mach-O arm
+
+CHECK: .debug_info contents:
+CHECK:  Compile Unit: length = 0x00000034, format = DWARF32, version = 0x0002, abbr_offset = 0x0000, addr_size = 0x04 (next unit at 0x00000038)
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]	( .debug_str[0x00000001] = "clang version 3.8.0 (trunk 243776)")
+CHECK:    DW_AT_language [DW_FORM_data2]	(DW_LANG_C99)
+CHECK:    DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000024] = "fat-test.c")
+CHECK:    DW_AT_stmt_list [DW_FORM_data4]	(0x00000000)
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]	( .debug_str[0x0000002f] = "/Inputs")
+CHECK:    DW_TAG_variable [2]
+CHECK:      DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000037] = "armv7s_var")
+CHECK:      DW_AT_type [DW_FORM_ref4]	(cu + 0x0030 => {0x00000030}
+CHECK:      DW_AT_external [DW_FORM_flag]	(0x01)
+CHECK:      DW_AT_decl_file [DW_FORM_data1]	("/Inputs/fat-test.c")
+CHECK:      DW_AT_decl_line [DW_FORM_data1]	(21)
+CHECK:      DW_AT_location [DW_FORM_block1]	(DW_OP_addr 0x1000)
+CHECK:    DW_TAG_base_type [3]
+CHECK:      DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000042] = "int")
+CHECK:      DW_AT_encoding [DW_FORM_data1]	(DW_ATE_signed)
+CHECK:      DW_AT_byte_size [DW_FORM_data1]	(0x04)
+CHECK:    NULL
+
+CHECK: .debug_line contents:
+CHECK: Line table prologue:
+CHECK:     total_length: 0x0000002a
+CHECK:          version: 2
+CHECK:  prologue_length: 0x00000021
+CHECK:  min_inst_length: 1
+CHECK:  default_is_stmt: 1
+CHECK:        line_base: -5
+CHECK:       line_range: 14
+CHECK:      opcode_base: 13
+
+CHECK: /Contents/Resources/DWARF/fat-test.arm.dylib(arm64):	file format Mach-O arm64
+
+CHECK: .debug_info contents:
+CHECK:  Compile Unit: length = 0x00000038, format = DWARF32, version = 0x0002, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x0000003c)
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]	( .debug_str[0x00000001] = "clang version 3.8.0 (trunk 243776)")
+CHECK:    DW_AT_language [DW_FORM_data2]	(DW_LANG_C99)
+CHECK:    DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000024] = "fat-test.c")
+CHECK:    DW_AT_stmt_list [DW_FORM_data4]	(0x00000000)
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]	( .debug_str[0x0000002f] = "/Inputs")
+CHECK:    DW_TAG_variable [2]
+CHECK:      DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000037] = "arm64_var")
+CHECK:      DW_AT_type [DW_FORM_ref4]	(cu + 0x0034 => {0x00000034}
+CHECK:      DW_AT_external [DW_FORM_flag]	(0x01)
+CHECK:      DW_AT_decl_file [DW_FORM_data1]	("/Inputs/fat-test.c")
+CHECK:      DW_AT_decl_line [DW_FORM_data1]	(25)
+CHECK:      DW_AT_location [DW_FORM_block1]	(DW_OP_addr 0x4000)
+CHECK:    DW_TAG_base_type [3]
+CHECK:      DW_AT_name [DW_FORM_strp]	( .debug_str[0x00000041] = "int")
+CHECK:      DW_AT_encoding [DW_FORM_data1]	(DW_ATE_signed)
+CHECK:      DW_AT_byte_size [DW_FORM_data1]	(0x04)
+CHECK:    NULL
+
+CHECK: .debug_line contents:
+CHECK: Line table prologue:
+CHECK:     total_length: 0x0000002a
+CHECK:          version: 2
+CHECK:  prologue_length: 0x00000021
+CHECK:  min_inst_length: 1
+CHECK:  default_is_stmt: 1
+CHECK:        line_base: -5
+CHECK:       line_range: 14
+CHECK:      opcode_base: 13

diff  --git a/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/obfuscated.test b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/obfuscated.test
new file mode 100644
index 00000000000000..640b5484b2c4e2
--- /dev/null
+++ b/llvm/test/tools/dsymutil/ARM/DWARFLinkerParallel/obfuscated.test
@@ -0,0 +1,119 @@
+REQUIRES: system-darwin
+
+RUN: dsymutil --linker llvm --symbol-map %p/../../Inputs/obfuscated.map %p/../../Inputs/obfuscated.arm64 -f -o - \
+RUN:     | llvm-dwarfdump -v - \
+RUN:     | FileCheck %s
+
+RUN: dsymutil --linker llvm --symbol-map %p/../../Inputs/obfuscated.map %p/../../Inputs/obfuscated.arm64 -f -o - \
+RUN:     | llvm-dwarfdump -v - \
+RUN:     | FileCheck --check-prefix=NOHIDDEN %s
+
+RUN: dsymutil --linker llvm --symbol-map %p/../../Inputs/obfuscated.2.map %p/../../Inputs/obfuscated.2.arm64 -f -o - \
+RUN:     | llvm-dwarfdump -v - \
+RUN:     | FileCheck --check-prefix=NOHIDDEN %s
+
+// Run with plist and make sure dsymutil finds it.
+RUN: mkdir -p %t.dSYM/Contents/Resources/DWARF/
+RUN: mkdir -p %t.mapdir
+RUN: cp %p/../../Inputs/obfuscated.arm64 %t.dSYM/Contents/Resources/DWARF/
+RUN: cp %p/../../Inputs/E828A486-8433-3A5E-B6DB-A6294D28133D.plist %t.dSYM/Contents/Resources/
+RUN: cp %p/../../Inputs/obfuscated.map %t.mapdir/506AA50A-6B26-3B37-86D2-DC6EBD57B720.bcsymbolmap
+RUN: dsymutil --linker llvm --symbol-map %t.mapdir %t.dSYM 2>&1 | FileCheck --check-prefix=OBFUSCATING %s
+
+// Run without plist and make sure dsymutil doesn't crash.
+RUN: rm %t.dSYM/Contents/Resources/E828A486-8433-3A5E-B6DB-A6294D28133D.plist
+RUN: dsymutil --linker llvm --symbol-map %t.mapdir %t.dSYM 2>&1 | FileCheck --check-prefix=NOTOBFUSCATING %s
+
+OBFUSCATING-NOT: not unobfuscating
+
+NOTOBFUSCATING: not unobfuscating
+
+NOHIDDEN-NOT: __hidden#
+
+CHECK: .debug_info contents:
+
+CHECK: DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "main.c")
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "main")
+
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "one.c")
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "one")
+
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "two.c")
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "two")
+
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "three.c")
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "three")
+
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "four.c")
+CHECK:    DW_AT_stmt_list [DW_FORM_data4]  (0x0000011e)
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "four")
+
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "five.c")
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "five")
+
+CHECK:  DW_TAG_compile_unit [1] *
+CHECK:    DW_AT_producer [DW_FORM_strp]    ( {{.*}} "Apple LLVM version 7.0.0 (clang-700.2.38.2)")
+CHECK:    DW_AT_name [DW_FORM_strp]        ( {{.*}} "six.c")
+CHECK:    DW_AT_comp_dir [DW_FORM_strp]    ( {{.*}} "/Users/steven/dev/alpena/tests/src")
+CHECK:    DW_TAG_subprogram [2]
+CHECK:      DW_AT_name [DW_FORM_strp]      ( {{.*}} "six")
+
+CHECK: .debug_line contents:
+CHECK: file_names[  1]:
+CHECK:            name: "main.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK: file_names[  1]:
+CHECK:            name: "one.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK:          length: 0x00000000
+CHECK: file_names[  1]:
+CHECK:            name: "two.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK:          length: 0x00000000
+CHECK: file_names[  1]:
+CHECK:            name: "three.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK:          length: 0x00000000
+CHECK: file_names[  1]:
+CHECK:            name: "four.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK:          length: 0x00000000
+CHECK: file_names[  1]:
+CHECK:            name: "five.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK:          length: 0x00000000
+CHECK: file_names[  1]:
+CHECK:            name: "six.c"
+CHECK:       dir_index: 0
+CHECK:        mod_time: 0x00000000
+CHECK:          length: 0x00000000

diff  --git a/llvm/test/tools/dsymutil/ARM/call-pc-reloc.test b/llvm/test/tools/dsymutil/ARM/call-pc-reloc.test
index f34e682697b017..8c2b2622a36588 100644
--- a/llvm/test/tools/dsymutil/ARM/call-pc-reloc.test
+++ b/llvm/test/tools/dsymutil/ARM/call-pc-reloc.test
@@ -17,4 +17,7 @@ $ clang -arch arm64 main.arm64.o -o main.arm64 -g
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/call_pc/main.arm64 -o %t.dSYM
 RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_pc
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/call_pc/main.arm64 -o %t.dSYM
+RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_pc
+
 CHECK: DW_AT_call_pc (0x0000000100007f94)

diff  --git a/llvm/test/tools/dsymutil/ARM/dwarf5-addr-base.test b/llvm/test/tools/dsymutil/ARM/dwarf5-addr-base.test
index 96973fe122c8c4..00dcde718e3622 100644
--- a/llvm/test/tools/dsymutil/ARM/dwarf5-addr-base.test
+++ b/llvm/test/tools/dsymutil/ARM/dwarf5-addr-base.test
@@ -49,9 +49,23 @@ RUN: rm -rf %t.dir && mkdir -p %t.dir
 RUN: dsymutil -y %p/dummy-debug-map-amr64.map -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base -o %t.dir/dwarf5-addr-base.dSYM
 RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s
 
+RUN: rm -rf %t.dir && mkdir -p %t.dir
+RUN: dsymutil --linker llvm -y %p/dummy-debug-map-amr64.map \
+RUN:   -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base \
+RUN:   -o %t.dir/dwarf5-addr-base.dSYM
+RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s
+
+RUN: rm -rf %t.dir && mkdir -p %t.dir
 RUN: dsymutil --update -y %p/dummy-debug-map-amr64.map -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base -o %t.dir/dwarf5-addr-base.dSYM
 RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s --check-prefix=UPD
 
+RUN: rm -rf %t.dir && mkdir -p %t.dir
+RUN: dsymutil --linker llvm --update -y %p/dummy-debug-map-amr64.map \
+RUN:   -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base \
+RUN:   -o %t.dir/dwarf5-addr-base.dSYM
+RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | \
+RUN:   FileCheck %s --check-prefix=UPD
+
 CHECK: .debug_info contents:
 CHECK-NEXT: 0x00000000: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08
 
@@ -62,7 +76,7 @@ CHECK: 0x0000002c:   DW_TAG_subprogram [2] * (0x0000000c)
 CHECK-NEXT:                DW_AT_low_pc [DW_FORM_addrx]    (indexed (00000000) address = 0x[[ADDR1:[0-9a-f]+]])
 
 
-CHECK: 0x0000004e: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08
+CHECK: 0x0000004e: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x00{{00|5a}}, addr_size = 0x08
 
 CHECK: 0x0000005a: DW_TAG_compile_unit [1] *
 CHECK:              DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000018)
@@ -70,9 +84,9 @@ CHECK:              DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000018)
 CHECK: 0x0000007a:   DW_TAG_subprogram [2] * (0x0000005a)
 CHECK-NEXT:                 DW_AT_low_pc [DW_FORM_addrx]    (indexed (00000000) address = 0x[[ADDR2:[0-9a-f]+]])
 
-CHECK: 0x0000009c: Compile Unit: length = 0x00000043, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08
+CHECK: 0x0000009c: Compile Unit: length = 0x00000043, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x00{{00|b4}}, addr_size = 0x08
 
-CHECK: 0x000000a8: DW_TAG_compile_unit [5] *
+CHECK: 0x000000a8: DW_TAG_compile_unit {{.*}} *
 CHECK: DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000028)
 
 CHECK: 0x000000c1:   DW_TAG_subprogram [2] * (0x000000a8)
@@ -111,7 +125,7 @@ UPD: 0x00000071:   DW_TAG_subprogram [5]   (0x0000000c)
 UPD-NEXT:                 DW_AT_low_pc [DW_FORM_addrx]    (indexed (00000003) address = 0x0000000000000010)
 
 
-UPD: 0x00000085: Compile Unit: length = 0x00000072, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08
+UPD: 0x00000085: Compile Unit: length = 0x00000072, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x00{{00|99}}, addr_size = 0x08
 
 UPD: 0x00000091: DW_TAG_compile_unit [1] *
 UPD:              DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000008)
@@ -125,12 +139,12 @@ UPD-NEXT:                 DW_AT_low_pc [DW_FORM_addrx]    (indexed (00000001) ad
 UPD: 0x000000dc:   DW_TAG_subprogram [3] * (0x00000091)
 UPD-NEXT:                 DW_AT_low_pc [DW_FORM_addrx]    (indexed (00000002) address = 0x0000000000000008)
 
-UPD: 0x000000fb: Compile Unit: length = 0x00000044, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08
+UPD: 0x000000fb: Compile Unit: length = 0x00000044, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0{{000|115}}, addr_size = 0x08
 
-UPD: 0x00000107: DW_TAG_compile_unit [7] *
+UPD: 0x00000107: DW_TAG_compile_unit {{.*}} *
 UPD: DW_AT_addr_base [DW_FORM_sec_offset]      (0x00000008)
 
-UPD: 0x00000124:   DW_TAG_subprogram [3] * (0x00000107)
+UPD: 0x00000124:   DW_TAG_subprogram {{.*}} * (0x00000107)
 UPD-NEXT:                 DW_AT_low_pc [DW_FORM_addrx]    (indexed (00000000) address = 0x0000000000000018)
 
 UPD: .debug_addr contents:

diff  --git a/llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test b/llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test
index f74c514ab51697..e54d05f941162c 100644
--- a/llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test
+++ b/llvm/test/tools/dsymutil/ARM/dwarf5-addrx-0x0-last.test
@@ -28,6 +28,14 @@ RUN: llvm-dwarfdump --verify %t.dSYM 2>&1 | FileCheck %s
 RUN: llvm-dwarfdump --verbose -debug-info %t.dSYM | FileCheck %s --check-prefix DEBUGINFO
 RUN: llvm-dwarfdump --verbose -debug-line %t.dSYM | FileCheck %s --check-prefix DEBUGLINE
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs \
+RUN:   %p/../Inputs/private/tmp/dwarf5/dwarf5-addrx-0x0-last.out \
+RUN:   -o %t.dSYM 2>&1 | FileCheck %s --allow-empty
+RUN: llvm-dwarfdump --verify %t.dSYM 2>&1 | FileCheck %s
+RUN: llvm-dwarfdump --verbose -debug-info %t.dSYM | FileCheck %s --check-prefix DEBUGINFO
+RUN: llvm-dwarfdump --verbose -debug-line %t.dSYM | FileCheck %s --check-prefix DEBUGLINE
+
+
 CHECK-NOT: error:
 
 DEBUGINFO:   DW_TAG_subprogram

diff  --git a/llvm/test/tools/dsymutil/ARM/dwarf5-str-offsets-base-strx.test b/llvm/test/tools/dsymutil/ARM/dwarf5-str-offsets-base-strx.test
index 4765d02a13f1aa..ac813fc6203708 100644
--- a/llvm/test/tools/dsymutil/ARM/dwarf5-str-offsets-base-strx.test
+++ b/llvm/test/tools/dsymutil/ARM/dwarf5-str-offsets-base-strx.test
@@ -1,4 +1,8 @@
 ; This test checks to ensure that if three DWARFv5 object files have correct values for the DW_AT_str_offsets_base and DW_FORM_strx for strings in their compile units.
+; DWARFLinkerParallel specific : DWARFLinkerParallel uses .debug_str_offsets
+; table local to the compile unit. That leads to 
diff erent string indexes.
+; In such cases test contains both variants for indexes value:
+; (indexed (0000000{{9|1}}) string = "b.cpp".
 
 ; 1.o was produced with the source file:
 
@@ -47,10 +51,21 @@
 
 RUN: rm -rf %t.dir && mkdir -p %t.dir
 RUN: dsymutil -y %p/dummy-debug-map-amr64.map -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base -o %t.dir/dwarf5-addr-base.dSYM
-RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s
+RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s --check-prefixes=CHECK,GLOBAL
 
 RUN: dsymutil --update -y %p/dummy-debug-map-amr64.map -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base -o %t.dir/dwarf5-addr-base.dSYM
-RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s --check-prefix=UPD
+RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s --check-prefixes=UPD,GLOBALUPD
+
+RUN: rm -rf %t.dir && mkdir -p %t.dir
+RUN: dsymutil --linker llvm -y %p/dummy-debug-map-amr64.map \
+RUN:   -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base \
+RUN:   -o %t.dir/dwarf5-addr-base.dSYM
+RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s --check-prefixes=CHECK,LOCAL
+
+RUN: dsymutil --linker llvm --update -y %p/dummy-debug-map-amr64.map \
+RUN:   -oso-prepend-path=%p/../Inputs/DWARF5-addr-base-str-off-base \
+RUN:   -o %t.dir/dwarf5-addr-base.dSYM
+RUN: llvm-dwarfdump %t.dir/dwarf5-addr-base.dSYM -a --verbose | FileCheck %s --check-prefixes=UPD,LOCALUPD
 
 CHECK: .debug_info contents:
 CHECK: 0x00000000: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x0000004e)
@@ -78,19 +93,19 @@ CHECK:                 DW_AT_name [DW_FORM_strx]       (indexed (00000008) strin
 
 CHECK: 0x0000004d:   NULL
 
-CHECK: 0x0000004e: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x0000009c)
+CHECK: 0x0000004e: Compile Unit: length = 0x0000004a, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x00{{00|5a}}, addr_size = 0x08 (next unit at 0x0000009c)
 
 CHECK: 0x0000005a: DW_TAG_compile_unit [1] *
 CHECK:               DW_AT_producer [DW_FORM_strx]     (indexed (00000000) string = "Apple clang version 15.0.0 (clang-1500.0.31.1)")
-CHECK:               DW_AT_name [DW_FORM_strx] (indexed (00000009) string = "b.cpp")
+CHECK:               DW_AT_name [DW_FORM_strx] (indexed (0000000{{9|1}}) string = "b.cpp")
 CHECK:               DW_AT_LLVM_sysroot [DW_FORM_strx] (indexed (00000002) string = "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk")
 CHECK:               DW_AT_APPLE_sdk [DW_FORM_strx]    (indexed (00000003) string = "MacOSX14.0.sdk")
-CHECK:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x00000008)
+CHECK:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x000000{{08|34}})
 CHECK:               DW_AT_comp_dir [DW_FORM_strx]     (indexed (00000004) string = "/Users/shubham/Development/test109275485")
 
 CHECK: 0x0000007a:   DW_TAG_subprogram [2] * (0x0000005a)
-CHECK:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (0000000a) string = "_Z4bar2i")
-CHECK:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000b) string = "bar2")
+CHECK:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (0000000{{a|5}}) string = "_Z4bar2i")
+CHECK:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000{{b|6}}) string = "bar2")
 
 CHECK: 0x0000008a:     DW_TAG_formal_parameter [3]   (0x0000007a)
 CHECK:                   DW_AT_name [DW_FORM_strx]     (indexed (00000007) string = "a")
@@ -102,22 +117,22 @@ CHECK:                 DW_AT_name [DW_FORM_strx]       (indexed (00000008) strin
 
 CHECK: 0x0000009b:   NULL
 
-CHECK: 0x0000009c: Compile Unit: length = 0x00000043, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x000000e3)
+CHECK: 0x0000009c: Compile Unit: length = 0x00000043, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x00{{00|b4}}, addr_size = 0x08 (next unit at 0x000000e3)
 
-CHECK: 0x000000a8: DW_TAG_compile_unit [5] *
+CHECK: 0x000000a8: DW_TAG_compile_unit {{.*}} *
 CHECK:               DW_AT_producer [DW_FORM_strx]     (indexed (00000000) string = "Apple clang version 15.0.0 (clang-1500.0.31.1)")
-CHECK:               DW_AT_name [DW_FORM_strx] (indexed (0000000c) string = "c.cpp")
+CHECK:               DW_AT_name [DW_FORM_strx] (indexed (0000000{{c|1}}) string = "c.cpp")
 CHECK:               DW_AT_LLVM_sysroot [DW_FORM_strx] (indexed (00000002) string = "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk")
 CHECK:               DW_AT_APPLE_sdk [DW_FORM_strx]    (indexed (00000003) string = "MacOSX14.0.sdk")
-CHECK:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x00000008)
+CHECK:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x000000{{08|60}})
 CHECK:               DW_AT_comp_dir [DW_FORM_strx]     (indexed (00000004) string = "/Users/shubham/Development/test109275485")
 
 CHECK: 0x000000c1:   DW_TAG_subprogram [2] * (0x000000a8)
-CHECK:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (0000000d) string = "_Z3bazi")
-CHECK:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000e) string = "baz")
+CHECK:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (0000000{{d|5}}) string = "_Z3bazi")
+CHECK:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000{{e|6}}) string = "baz")
 
 CHECK: 0x000000d1:     DW_TAG_formal_parameter [3]   (0x000000c1)
-CHECK:                   DW_AT_name [DW_FORM_strx]     (indexed (0000000f) string = "x")
+CHECK:                   DW_AT_name [DW_FORM_strx]     (indexed (0000000{{f|7}}) string = "x")
 
 CHECK: 0x000000dd:     NULL
 
@@ -145,24 +160,57 @@ CHECK-NEXT: 0x0000011d: "_Z3bazi"
 CHECK-NEXT: 0x00000125: "baz"
 CHECK-NEXT: 0x00000129: "x"
 
-CHECK: .debug_str_offsets contents:
-CHECK-NEXT: 0x00000000: Contribution size = 68, Format = DWARF32, Version = 5
-CHECK-NEXT: 0x00000008: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
-CHECK-NEXT: 0x0000000c: 00000030 "a.cpp"
-CHECK-NEXT: 0x00000010: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
-CHECK-NEXT: 0x00000014: 000000b7 "MacOSX14.0.sdk"
-CHECK-NEXT: 0x00000018: 000000c6 "/Users/shubham/Development/test109275485"
-CHECK-NEXT: 0x0000001c: 000000ef "_Z4foo2i"
-CHECK-NEXT: 0x00000020: 000000f8 "foo2"
-CHECK-NEXT: 0x00000024: 000000fd "a"
-CHECK-NEXT: 0x00000028: 000000ff "int"
-CHECK-NEXT: 0x0000002c: 00000103 "b.cpp"
-CHECK-NEXT: 0x00000030: 00000109 "_Z4bar2i"
-CHECK-NEXT: 0x00000034: 00000112 "bar2"
-CHECK-NEXT: 0x00000038: 00000117 "c.cpp"
-CHECK-NEXT: 0x0000003c: 0000011d "_Z3bazi"
-CHECK-NEXT: 0x00000040: 00000125 "baz"
-CHECK-NEXT: 0x00000044: 00000129 "x"
+GLOBAL: .debug_str_offsets contents:
+GLOBAL-NEXT: 0x00000000: Contribution size = 68, Format = DWARF32, Version = 5
+GLOBAL-NEXT: 0x00000008: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+GLOBAL-NEXT: 0x0000000c: 00000030 "a.cpp"
+GLOBAL-NEXT: 0x00000010: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+GLOBAL-NEXT: 0x00000014: 000000b7 "MacOSX14.0.sdk"
+GLOBAL-NEXT: 0x00000018: 000000c6 "/Users/shubham/Development/test109275485"
+GLOBAL-NEXT: 0x0000001c: 000000ef "_Z4foo2i"
+GLOBAL-NEXT: 0x00000020: 000000f8 "foo2"
+GLOBAL-NEXT: 0x00000024: 000000fd "a"
+GLOBAL-NEXT: 0x00000028: 000000ff "int"
+GLOBAL-NEXT: 0x0000002c: 00000103 "b.cpp"
+GLOBAL-NEXT: 0x00000030: 00000109 "_Z4bar2i"
+GLOBAL-NEXT: 0x00000034: 00000112 "bar2"
+GLOBAL-NEXT: 0x00000038: 00000117 "c.cpp"
+GLOBAL-NEXT: 0x0000003c: 0000011d "_Z3bazi"
+GLOBAL-NEXT: 0x00000040: 00000125 "baz"
+GLOBAL-NEXT: 0x00000044: 00000129 "x"
+
+LOCAL: .debug_str_offsets contents:
+LOCAL-NEXT: 0x00000000: Contribution size = 40, Format = DWARF32, Version = 5
+LOCAL-NEXT: 0x00000008: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+LOCAL-NEXT: 0x0000000c: 00000030 "a.cpp"
+LOCAL-NEXT: 0x00000010: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+LOCAL-NEXT: 0x00000014: 000000b7 "MacOSX14.0.sdk"
+LOCAL-NEXT: 0x00000018: 000000c6 "/Users/shubham/Development/test109275485"
+LOCAL-NEXT: 0x0000001c: 000000ef "_Z4foo2i"
+LOCAL-NEXT: 0x00000020: 000000f8 "foo2"
+LOCAL-NEXT: 0x00000024: 000000fd "a"
+LOCAL-NEXT: 0x00000028: 000000ff "int"
+LOCAL-NEXT: 0x0000002c: Contribution size = 40, Format = DWARF32, Version = 5
+LOCAL-NEXT: 0x00000034: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+LOCAL-NEXT: 0x00000038: 00000103 "b.cpp"
+LOCAL-NEXT: 0x0000003c: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+LOCAL-NEXT: 0x00000040: 000000b7 "MacOSX14.0.sdk"
+LOCAL-NEXT: 0x00000044: 000000c6 "/Users/shubham/Development/test109275485"
+LOCAL-NEXT: 0x00000048: 00000109 "_Z4bar2i"
+LOCAL-NEXT: 0x0000004c: 00000112 "bar2"
+LOCAL-NEXT: 0x00000050: 000000fd "a"
+LOCAL-NEXT: 0x00000054: 000000ff "int"
+LOCAL-NEXT: 0x00000058: Contribution size = 40, Format = DWARF32, Version = 5
+LOCAL-NEXT: 0x00000060: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+LOCAL-NEXT: 0x00000064: 00000117 "c.cpp"
+LOCAL-NEXT: 0x00000068: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+LOCAL-NEXT: 0x0000006c: 000000b7 "MacOSX14.0.sdk"
+LOCAL-NEXT: 0x00000070: 000000c6 "/Users/shubham/Development/test109275485"
+LOCAL-NEXT: 0x00000074: 0000011d "_Z3bazi"
+LOCAL-NEXT: 0x00000078: 00000125 "baz"
+LOCAL-NEXT: 0x0000007c: 00000129 "x"
+LOCAL-NEXT: 0x00000080: 000000ff "int"
+
 
 UPD: .debug_info contents:
 UPD: 0x00000000: Compile Unit: length = 0x00000081, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x00000085)
@@ -205,23 +253,23 @@ UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000e) string
 
 UPD: 0x00000084:   NULL
 
-UPD: 0x00000085: Compile Unit: length = 0x00000072, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x000000fb)
+UPD: 0x00000085: Compile Unit: length = 0x00000072, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x00{{00|99}}, addr_size = 0x08 (next unit at 0x000000fb)
 
 UPD: 0x00000091: DW_TAG_compile_unit [1] *
 UPD:               DW_AT_producer [DW_FORM_strx]     (indexed (00000000) string = "Apple clang version 15.0.0 (clang-1500.0.31.1)")
-UPD:               DW_AT_name [DW_FORM_strx] (indexed (0000000f) string = "b.cpp")
+UPD:               DW_AT_name [DW_FORM_strx] (indexed (0000000{{f|1}}) string = "b.cpp")
 UPD:               DW_AT_LLVM_sysroot [DW_FORM_strx] (indexed (00000002) string = "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk")
 UPD:               DW_AT_APPLE_sdk [DW_FORM_strx]    (indexed (00000003) string = "MacOSX14.0.sdk")
-UPD:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x00000008)
+UPD:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x000000{{08|4c}})
 UPD:               DW_AT_comp_dir [DW_FORM_strx]     (indexed (00000004) string = "/Users/shubham/Development/test109275485")
 
 UPD: 0x000000b6:   DW_TAG_subprogram [2]   (0x00000091)
-UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (00000010) string = "_Z3barv")
-UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (00000011) string = "bar")
+UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (000000{{10|05}}) string = "_Z3barv")
+UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (000000{{11|06}}) string = "bar")
 
 UPD: 0x000000c2:   DW_TAG_subprogram [3] * (0x00000091)
-UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (00000012) string = "_Z4bar2i")
-UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (00000013) string = "bar2")
+UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (000000{{12|07}}) string = "_Z4bar2i")
+UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (000000{{13|08}}) string = "bar2")
 
 UPD: 0x000000d2:     DW_TAG_formal_parameter [4]   (0x000000c2)
 UPD:                   DW_AT_name [DW_FORM_strx]     (indexed (00000009) string = "a")
@@ -229,40 +277,40 @@ UPD:                   DW_AT_name [DW_FORM_strx]     (indexed (00000009) string
 UPD: 0x000000db:     NULL
 
 UPD: 0x000000dc:   DW_TAG_subprogram [3] * (0x00000091)
-UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (00000014) string = "_Z4bar3i")
-UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (00000015) string = "bar3")
+UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (000000{{14|0a}}) string = "_Z4bar3i")
+UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (000000{{15|0b}}) string = "bar3")
 
 UPD: 0x000000ec:     DW_TAG_formal_parameter [4]   (0x000000dc)
 UPD:                   DW_AT_name [DW_FORM_strx]     (indexed (0000000c) string = "x")
 
 UPD: 0x000000f5:     NULL
 
-UPD: 0x000000f6:   DW_TAG_base_type [6]   (0x00000091)
-UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000e) string = "int")
+UPD: 0x000000f6:   DW_TAG_base_type {{.*}}   (0x00000091)
+UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000{{e|d}}) string = "int")
 
 UPD: 0x000000fa:   NULL
 
-UPD: 0x000000fb: Compile Unit: length = 0x00000044, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x00000143)
+UPD: 0x000000fb: Compile Unit: length = 0x00000044, format = DWARF32, version = 0x0005, unit_type = DW_UT_compile, abbr_offset = 0x0{{000|115}}, addr_size = 0x08 (next unit at 0x00000143)
 
-UPD: 0x00000107: DW_TAG_compile_unit [7] *
+UPD: 0x00000107: DW_TAG_compile_unit {{.*}} *
 UPD:               DW_AT_producer [DW_FORM_strx]     (indexed (00000000) string = "Apple clang version 15.0.0 (clang-1500.0.31.1)")
-UPD:               DW_AT_name [DW_FORM_strx] (indexed (00000016) string = "c.cpp")
+UPD:               DW_AT_name [DW_FORM_strx] (indexed (000000{{16|01}}) string = "c.cpp")
 UPD:               DW_AT_LLVM_sysroot [DW_FORM_strx] (indexed (00000002) string = "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk")
 UPD:               DW_AT_APPLE_sdk [DW_FORM_strx]    (indexed (00000003) string = "MacOSX14.0.sdk")
-UPD:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x00000008)
+UPD:               DW_AT_str_offsets_base [DW_FORM_sec_offset]       (0x000000{{08|8c}})
 UPD:               DW_AT_comp_dir [DW_FORM_strx]     (indexed (00000004) string = "/Users/shubham/Development/test109275485")
 
-UPD: 0x00000124:   DW_TAG_subprogram [3] * (0x00000107)
-UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (00000017) string = "_Z3bazi")
-UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (00000018) string = "baz")
+UPD: 0x00000124:   DW_TAG_subprogram {{.*}} * (0x00000107)
+UPD:                 DW_AT_linkage_name [DW_FORM_strx]       (indexed (000000{{17|05}}) string = "_Z3bazi")
+UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (000000{{18|06}}) string = "baz")
 
-UPD: 0x00000134:     DW_TAG_formal_parameter [4]   (0x00000124)
-UPD:                   DW_AT_name [DW_FORM_strx]     (indexed (0000000c) string = "x")
+UPD: 0x00000134:     DW_TAG_formal_parameter {{.*}}   (0x00000124)
+UPD:                   DW_AT_name [DW_FORM_strx]     (indexed (0000000{{c|7}}) string = "x")
 
 UPD: 0x0000013d:     NULL
 
-UPD: 0x0000013e:   DW_TAG_base_type [6]   (0x00000107)
-UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000e) string = "int")
+UPD: 0x0000013e:   DW_TAG_base_type {{.*}}   (0x00000107)
+UPD:                 DW_AT_name [DW_FORM_strx]       (indexed (0000000{{e|8}}) string = "int")
 
 UPD: 0x00000142:   NULL
 
@@ -294,30 +342,73 @@ UPD-NEXT: 0x00000152: "c.cpp"
 UPD-NEXT: 0x00000158: "_Z3bazi"
 UPD-NEXT: 0x00000160: "baz"
 
-UPD: .debug_str_offsets contents:
-UPD-NEXT: 0x00000000: Contribution size = 104, Format = DWARF32, Version = 5
-UPD-NEXT: 0x00000008: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
-UPD-NEXT: 0x0000000c: 00000030 "a.cpp"
-UPD-NEXT: 0x00000010: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
-UPD-NEXT: 0x00000014: 000000b7 "MacOSX14.0.sdk"
-UPD-NEXT: 0x00000018: 000000c6 "/Users/shubham/Development/test109275485"
-UPD-NEXT: 0x0000001c: 000000ef "_Z3foov"
-UPD-NEXT: 0x00000020: 000000f7 "foo"
-UPD-NEXT: 0x00000024: 000000fb "_Z4foo2i"
-UPD-NEXT: 0x00000028: 00000104 "foo2"
-UPD-NEXT: 0x0000002c: 00000109 "a"
-UPD-NEXT: 0x00000030: 0000010b "_Z4foo3i"
-UPD-NEXT: 0x00000034: 00000114 "foo3"
-UPD-NEXT: 0x00000038: 00000119 "x"
-UPD-NEXT: 0x0000003c: 0000011b "main"
-UPD-NEXT: 0x00000040: 00000120 "int"
-UPD-NEXT: 0x00000044: 00000124 "b.cpp"
-UPD-NEXT: 0x00000048: 0000012a "_Z3barv"
-UPD-NEXT: 0x0000004c: 00000132 "bar"
-UPD-NEXT: 0x00000050: 00000136 "_Z4bar2i"
-UPD-NEXT: 0x00000054: 0000013f "bar2"
-UPD-NEXT: 0x00000058: 00000144 "_Z4bar3i"
-UPD-NEXT: 0x0000005c: 0000014d "bar3"
-UPD-NEXT: 0x00000060: 00000152 "c.cpp"
-UPD-NEXT: 0x00000064: 00000158 "_Z3bazi"
-UPD-NEXT: 0x00000068: 00000160 "baz"
+GLOBALUPD: .debug_str_offsets contents:
+GLOBALUPD-NEXT: 0x00000000: Contribution size = 104, Format = DWARF32, Version = 5
+GLOBALUPD-NEXT: 0x00000008: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+GLOBALUPD-NEXT: 0x0000000c: 00000030 "a.cpp"
+GLOBALUPD-NEXT: 0x00000010: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+GLOBALUPD-NEXT: 0x00000014: 000000b7 "MacOSX14.0.sdk"
+GLOBALUPD-NEXT: 0x00000018: 000000c6 "/Users/shubham/Development/test109275485"
+GLOBALUPD-NEXT: 0x0000001c: 000000ef "_Z3foov"
+GLOBALUPD-NEXT: 0x00000020: 000000f7 "foo"
+GLOBALUPD-NEXT: 0x00000024: 000000fb "_Z4foo2i"
+GLOBALUPD-NEXT: 0x00000028: 00000104 "foo2"
+GLOBALUPD-NEXT: 0x0000002c: 00000109 "a"
+GLOBALUPD-NEXT: 0x00000030: 0000010b "_Z4foo3i"
+GLOBALUPD-NEXT: 0x00000034: 00000114 "foo3"
+GLOBALUPD-NEXT: 0x00000038: 00000119 "x"
+GLOBALUPD-NEXT: 0x0000003c: 0000011b "main"
+GLOBALUPD-NEXT: 0x00000040: 00000120 "int"
+GLOBALUPD-NEXT: 0x00000044: 00000124 "b.cpp"
+GLOBALUPD-NEXT: 0x00000048: 0000012a "_Z3barv"
+GLOBALUPD-NEXT: 0x0000004c: 00000132 "bar"
+GLOBALUPD-NEXT: 0x00000050: 00000136 "_Z4bar2i"
+GLOBALUPD-NEXT: 0x00000054: 0000013f "bar2"
+GLOBALUPD-NEXT: 0x00000058: 00000144 "_Z4bar3i"
+GLOBALUPD-NEXT: 0x0000005c: 0000014d "bar3"
+GLOBALUPD-NEXT: 0x00000060: 00000152 "c.cpp"
+GLOBALUPD-NEXT: 0x00000064: 00000158 "_Z3bazi"
+GLOBALUPD-NEXT: 0x00000068: 00000160 "baz"
+
+LOCALUPD: .debug_str_offsets contents:
+LOCALUPD-NEXT: 0x00000000: Contribution size = 64, Format = DWARF32, Version = 5
+LOCALUPD-NEXT: 0x00000008: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+LOCALUPD-NEXT: 0x0000000c: 00000030 "a.cpp"
+LOCALUPD-NEXT: 0x00000010: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+LOCALUPD-NEXT: 0x00000014: 000000b7 "MacOSX14.0.sdk"
+LOCALUPD-NEXT: 0x00000018: 000000c6 "/Users/shubham/Development/test109275485"
+LOCALUPD-NEXT: 0x0000001c: 000000ef "_Z3foov"
+LOCALUPD-NEXT: 0x00000020: 000000f7 "foo"
+LOCALUPD-NEXT: 0x00000024: 000000fb "_Z4foo2i"
+LOCALUPD-NEXT: 0x00000028: 00000104 "foo2"
+LOCALUPD-NEXT: 0x0000002c: 00000109 "a"
+LOCALUPD-NEXT: 0x00000030: 0000010b "_Z4foo3i"
+LOCALUPD-NEXT: 0x00000034: 00000114 "foo3"
+LOCALUPD-NEXT: 0x00000038: 00000119 "x"
+LOCALUPD-NEXT: 0x0000003c: 0000011b "main"
+LOCALUPD-NEXT: 0x00000040: 00000120 "int"
+LOCALUPD-NEXT: 0x00000044: Contribution size = 60, Format = DWARF32, Version = 5
+LOCALUPD-NEXT: 0x0000004c: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+LOCALUPD-NEXT: 0x00000050: 00000124 "b.cpp"
+LOCALUPD-NEXT: 0x00000054: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+LOCALUPD-NEXT: 0x00000058: 000000b7 "MacOSX14.0.sdk"
+LOCALUPD-NEXT: 0x0000005c: 000000c6 "/Users/shubham/Development/test109275485"
+LOCALUPD-NEXT: 0x00000060: 0000012a "_Z3barv"
+LOCALUPD-NEXT: 0x00000064: 00000132 "bar"
+LOCALUPD-NEXT: 0x00000068: 00000136 "_Z4bar2i"
+LOCALUPD-NEXT: 0x0000006c: 0000013f "bar2"
+LOCALUPD-NEXT: 0x00000070: 00000109 "a"
+LOCALUPD-NEXT: 0x00000074: 00000144 "_Z4bar3i"
+LOCALUPD-NEXT: 0x00000078: 0000014d "bar3"
+LOCALUPD-NEXT: 0x0000007c: 00000119 "x"
+LOCALUPD-NEXT: 0x00000080: 00000120 "int"
+LOCALUPD-NEXT: 0x00000084: Contribution size = 40, Format = DWARF32, Version = 5
+LOCALUPD-NEXT: 0x0000008c: 00000001 "Apple clang version 15.0.0 (clang-1500.0.31.1)"
+LOCALUPD-NEXT: 0x00000090: 00000152 "c.cpp"
+LOCALUPD-NEXT: 0x00000094: 00000036 "/Users/shubham/apple-internal/Xcode-Rainbow/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.0.sdk"
+LOCALUPD-NEXT: 0x00000098: 000000b7 "MacOSX14.0.sdk"
+LOCALUPD-NEXT: 0x0000009c: 000000c6 "/Users/shubham/Development/test109275485"
+LOCALUPD-NEXT: 0x000000a0: 00000158 "_Z3bazi"
+LOCALUPD-NEXT: 0x000000a4: 00000160 "baz"
+LOCALUPD-NEXT: 0x000000a8: 00000119 "x"
+LOCALUPD-NEXT: 0x000000ac: 00000120 "int"

diff  --git a/llvm/test/tools/dsymutil/ARM/empty-map.test b/llvm/test/tools/dsymutil/ARM/empty-map.test
index d80311e5f5c31e..2668d46ed6d7d5 100644
--- a/llvm/test/tools/dsymutil/ARM/empty-map.test
+++ b/llvm/test/tools/dsymutil/ARM/empty-map.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s
+
 ---
 triple:          'thumbv7-apple-darwin'
 ...

diff  --git a/llvm/test/tools/dsymutil/ARM/extern-alias.test b/llvm/test/tools/dsymutil/ARM/extern-alias.test
index cb459fbd662899..f8b59584d2b465 100644
--- a/llvm/test/tools/dsymutil/ARM/extern-alias.test
+++ b/llvm/test/tools/dsymutil/ARM/extern-alias.test
@@ -37,6 +37,10 @@ $ xcrun --sdk iphoneos clang private_extern.o main.o -target arm64-apple-ios14.0
 
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/private_extern/private_extern.out -o %t.dSYM --verbose | FileCheck %s
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/extern/extern.out -o %t.dSYM --verbose | FileCheck %s
+
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/private_extern/private_extern.out -o %t.dSYM --verbose | FileCheck %s
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/extern/extern.out -o %t.dSYM --verbose | FileCheck %s
+
 CHECK-NOT: could not find object file symbol for symbol _baz
 CHECK: { sym: _baz, objAddr: 0x0, binAddr: 0x100007F58, size: 0x0 }
 CHECK: { sym: _foo, objAddr: 0x0, binAddr: 0x100007F58, size: 0x20 }

diff  --git a/llvm/test/tools/dsymutil/ARM/fat-arch-name.test b/llvm/test/tools/dsymutil/ARM/fat-arch-name.test
index 4f7866d4d22de4..4840de13af582f 100644
--- a/llvm/test/tools/dsymutil/ARM/fat-arch-name.test
+++ b/llvm/test/tools/dsymutil/ARM/fat-arch-name.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -no-output %p/../Inputs/fat-test.arm.dylib -o /dev/null -verbose 2>&1 | FileCheck %s
 
+# RUN: dsymutil --linker llvm -no-output %p/../Inputs/fat-test.arm.dylib -o /dev/null -verbose 2>&1 | FileCheck %s
+
 # We detect thumb triples from the binaries, because those are the only ones
 # that are guaranteed to be able to generate a Target instance (for example
 # we would detect armv7m-apple-darwin as non-thumb triple, but you can't

diff  --git a/llvm/test/tools/dsymutil/ARM/fat-arch-not-found.test b/llvm/test/tools/dsymutil/ARM/fat-arch-not-found.test
index b223299204aab6..59d2ccc783840f 100644
--- a/llvm/test/tools/dsymutil/ARM/fat-arch-not-found.test
+++ b/llvm/test/tools/dsymutil/ARM/fat-arch-not-found.test
@@ -1,4 +1,6 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s
+#
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs -y %s -o - 2>&1 | FileCheck %s
 
 ---
 triple:          'armv7-apple-darwin'

diff  --git a/llvm/test/tools/dsymutil/ARM/inlined-low_pc.c b/llvm/test/tools/dsymutil/ARM/inlined-low_pc.c
index 99fe0450dc8348..9cd10be1ec3cf4 100644
--- a/llvm/test/tools/dsymutil/ARM/inlined-low_pc.c
+++ b/llvm/test/tools/dsymutil/ARM/inlined-low_pc.c
@@ -5,6 +5,10 @@ int bar(int a) { return foo(a); }
 
 // RUN: dsymutil -f -y %p/dummy-debug-map-amr64.map -oso-prepend-path %p/../Inputs/inlined-low_pc -o - | llvm-dwarfdump - | FileCheck %s
 
+// RUN: dsymutil --linker llvm -f -y %p/dummy-debug-map-amr64.map \
+// RUN: -oso-prepend-path %p/../Inputs/inlined-low_pc -o - | \
+// RUN: llvm-dwarfdump - | FileCheck %s
+
 // CHECK: DW_TAG_subprogram
 // CHECK: DW_AT_low_pc{{.*}}0x0000000000010000
 // CHECK: DW_AT_name{{.*}}"bar"

diff  --git a/llvm/test/tools/dsymutil/ARM/preload.test b/llvm/test/tools/dsymutil/ARM/preload.test
index 3caa4a22c4a03f..2d1ac9b455d1b5 100644
--- a/llvm/test/tools/dsymutil/ARM/preload.test
+++ b/llvm/test/tools/dsymutil/ARM/preload.test
@@ -7,4 +7,9 @@ $ xcrun clang -o foo foo.o -g3 -Wl,-preload -nodefaultlibs
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/preload/foo -o %t.dSYM
 RUN: llvm-nm %p/../Inputs/private/tmp/preload/foo | FileCheck %s
 RUN: llvm-nm %t.dSYM/Contents/Resources/DWARF/foo | FileCheck %s
+
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/preload/foo -o %t.dSYM
+RUN: llvm-nm %p/../Inputs/private/tmp/preload/foo | FileCheck %s
+RUN: llvm-nm %t.dSYM/Contents/Resources/DWARF/foo | FileCheck %s
+
 CHECK: start

diff  --git a/llvm/test/tools/dsymutil/ARM/scattered.c b/llvm/test/tools/dsymutil/ARM/scattered.c
index 81082bcd736bfe..75076f96cadd83 100644
--- a/llvm/test/tools/dsymutil/ARM/scattered.c
+++ b/llvm/test/tools/dsymutil/ARM/scattered.c
@@ -1,4 +1,10 @@
-RUN: dsymutil -y %p/dummy-debug-map.map -oso-prepend-path %p/../Inputs/scattered-reloc/ -f -o - | llvm-dwarfdump -debug-info - | FileCheck %s
+RUN: dsymutil -y %p/dummy-debug-map.map -oso-prepend-path \
+RUN:  %p/../Inputs/scattered-reloc/ -f -o - | \
+RUN:  llvm-dwarfdump -debug-info - | FileCheck %s
+
+RUN: dsymutil --linker llvm -y %p/dummy-debug-map.map \
+RUN:  -oso-prepend-path %p/../Inputs/scattered-reloc/ -f -o - \
+RUN:  | llvm-dwarfdump -debug-info - | FileCheck %s
 
 // See Inputs/scattered-reloc/scattered.s to see how this test
 // actually works.

diff  --git a/llvm/test/tools/dsymutil/ARM/thumb.c b/llvm/test/tools/dsymutil/ARM/thumb.c
index 81602d17e8776d..205ddd07106849 100644
--- a/llvm/test/tools/dsymutil/ARM/thumb.c
+++ b/llvm/test/tools/dsymutil/ARM/thumb.c
@@ -1,6 +1,11 @@
 // RUN: dsymutil -f -oso-prepend-path=%p/.. %p/../Inputs/thumb.armv7m -o - | llvm-dwarfdump - | FileCheck %s
 // RUN: dsymutil -arch armv7m -f -oso-prepend-path=%p/.. %p/../Inputs/thumb.armv7m -o - | llvm-dwarfdump - | FileCheck %s
 
+// RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/.. \
+// RUN:  %p/../Inputs/thumb.armv7m -o - | llvm-dwarfdump - | FileCheck %s
+// RUN: dsymutil --linker llvm -arch armv7m -f -oso-prepend-path=%p/.. \
+// RUN:  %p/../Inputs/thumb.armv7m -o - | llvm-dwarfdump - | FileCheck %s
+
 /* Compile with:
    clang -c thumb.c -arch armv7m -g
    clang thumb.o -o thumb.armv7m -arch armv7m -nostdlib -static -Wl,-e,_start

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-bundle.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-bundle.test
new file mode 100644
index 00000000000000..ae92280840e792
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-bundle.test
@@ -0,0 +1,41 @@
+RUN: rm -rf %t
+RUN: mkdir -p %t/dsymdest
+RUN: cat %p/../../Inputs/basic.macho.x86_64 > %t/basic.macho.x86_64
+
+RUN: dsymutil --linker llvm -accelerator=Pub -oso-prepend-path=%p/../.. %t/basic.macho.x86_64
+
+Check that the object file in the bundle exists and is sane:
+RUN: llvm-dwarfdump -a %t/basic.macho.x86_64.dSYM/Contents/Resources/DWARF/basic.macho.x86_64 | FileCheck %S/basic-linking-x86.test
+
+Check that we don't create an empty Remarks directory if there are no remarks.
+RUN: not ls %t/basic.macho.x86_64.dSYM/Contents/Resources/Remarks
+
+Check that llvm-dwarfdump -a recognizes the bundle as a dSYM:
+RUN: llvm-dwarfdump -a %t/basic.macho.x86_64.dSYM | FileCheck %S/basic-linking-x86.test
+
+RUN: FileCheck %s --input-file %t/basic.macho.x86_64.dSYM/Contents/Info.plist
+
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../.. %t/basic.macho.x86_64 -o %t/dsymdest/basic.macho.x86_64.dSYM
+RUN: llvm-dwarfdump -a %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Resources/DWARF/basic.macho.x86_64 | FileCheck %S/basic-linking-x86.test
+RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info.plist
+
+CHECK: <?xml version="1.0" encoding="UTF-8"?>
+CHECK-NEXT: <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+CHECK-NEXT: <plist version="1.0">
+CHECK-NEXT:         <dict>
+CHECK-NEXT:                 <key>CFBundleDevelopmentRegion</key>
+CHECK-NEXT:                 <string>English</string>
+CHECK-NEXT:                 <key>CFBundleIdentifier</key>
+CHECK-NEXT:                 <string>com.apple.xcode.dsym.basic.macho.x86_64</string>
+CHECK-NEXT:                 <key>CFBundleInfoDictionaryVersion</key>
+CHECK-NEXT:                 <string>6.0</string>
+CHECK-NEXT:                 <key>CFBundlePackageType</key>
+CHECK-NEXT:                 <string>dSYM</string>
+CHECK-NEXT:                 <key>CFBundleSignature</key>
+CHECK-NEXT:                 <string>????</string>
+CHECK-NEXT:                 <key>CFBundleShortVersionString</key>
+CHECK-NEXT:                 <string>1.0</string>
+CHECK-NEXT:                 <key>CFBundleVersion</key>
+CHECK-NEXT:                 <string>1</string>
+CHECK-NEXT:         </dict>
+CHECK-NEXT: </plist>

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-x86.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-x86.test
index ba5bc6f4a3e504..b65529e487237e 100644
--- a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-x86.test
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-linking-x86.test
@@ -1,4 +1,190 @@
 RUN: cat %p/../../Inputs/basic.macho.x86_64 > %t1
-RUN: dsymutil --linker llvm --no-output -accelerator=Pub -f -oso-prepend-path=%p/../.. %t1 2>&1 | FileCheck %s --allow-empty
+RUN: dsymutil --linker llvm -accelerator=Pub -f -oso-prepend-path=%p/../.. %t1
+RUN: llvm-dwarfdump -a %t1.dwarf | FileCheck %s
+RUN: dsymutil --linker llvm -accelerator=Pub -f -o %t2 -oso-prepend-path=%p/../.. %p/../../Inputs/basic.macho.x86_64
+RUN: llvm-dwarfdump -a %t2 | FileCheck %s
+RUN: dsymutil --linker llvm -accelerator=Pub -f -o - -oso-prepend-path=%p/../.. %p/../../Inputs/basic.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,BASIC
+RUN: dsymutil --linker llvm -accelerator=Pub -f -o - -oso-prepend-path=%p/../.. %p/../../Inputs/basic-archive.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,ARCHIVE
+RUN: dsymutil --linker llvm -accelerator=Pub -dump-debug-map -oso-prepend-path=%p/../.. %p/../../Inputs/basic.macho.x86_64 | dsymutil -accelerator=Pub -f -y -o - - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,BASIC
+RUN: dsymutil --linker llvm -accelerator=Pub -dump-debug-map -oso-prepend-path=%p/../.. %p/../../Inputs/basic-archive.macho.x86_64 | dsymutil -accelerator=Pub -f -o - -y - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,ARCHIVE
 
-#CHECK: LLVM parallel dwarflinker is not implemented yet.
+CHECK: file format Mach-O 64-bit x86-64
+
+CHECK: debug_info contents
+
+CHECK:  Compile Unit:
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")
+CHECK:    DW_AT_language (DW_LANG_C99)
+CHECK:    DW_AT_name ("basic1.c")
+CHECK:    DW_AT_stmt_list (0x00000000)
+CHECK:    DW_AT_comp_dir ("/Inputs")
+CHECK:    DW_AT_low_pc (0x0000000100000ea0)
+CHECK:    DW_TAG_subprogram
+CHECK:    DW_AT_name ("main")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic1.c")
+CHECK:      DW_AT_decl_line (23)
+CHECK:      DW_AT_prototyped (0x01)
+CHECK:      DW_AT_type (0x00000063
+CHECK:      DW_AT_external (0x01)
+CHECK:      DW_AT_accessibility (DW_ACCESS_public)
+CHECK:      DW_AT_low_pc (0x0000000100000ea0)
+CHECK:      DW_AT_high_pc (0x0000000100000ec4)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("argc")
+CHECK:        DW_AT_decl_file ("/Inputs{{[/\\]}}basic1.c")
+CHECK:        DW_AT_decl_line (23)
+CHECK:        DW_AT_type (0x00000063
+CHECK:        DW_AT_location (DW_OP_fbreg -8)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("argv")
+CHECK:        DW_AT_decl_file ("/Inputs{{[/\\]}}basic1.c")
+CHECK:        DW_AT_decl_line (23)
+CHECK:        DW_AT_type (0x0000006a
+CHECK:        DW_AT_location (DW_OP_fbreg -16)
+CHECK:      NULL
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("int")
+CHECK:      DW_AT_encoding (DW_ATE_signed)
+CHECK:      DW_AT_byte_size (0x04)
+CHECK:    DW_TAG_pointer_type
+CHECK:      DW_AT_type (0x0000006f
+CHECK:    DW_TAG_pointer_type
+CHECK:      DW_AT_type (0x00000074
+CHECK:    DW_TAG_const_type
+CHECK:      DW_AT_type (0x00000079
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("char")
+CHECK:      DW_AT_encoding (DW_ATE_signed_char)
+CHECK:      DW_AT_byte_size (0x01)
+CHECK:    NULL
+
+CHECK:  Compile Unit:
+
+CHECK:  DW_TAG_compile_unit
+CHECK:   DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")
+CHECK:   DW_AT_name ("basic2.c")
+CHECK:   DW_AT_stmt_list (0x0000003f)
+CHECK:   DW_AT_comp_dir ("/Inputs")
+CHECK:   DW_AT_low_pc (0x0000000100000ed0)
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("int")
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("private_int")
+CHECK:      DW_AT_type (0x000000a7
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic2.c")
+BASIC:      DW_AT_location (DW_OP_addr 0x100001008)
+ARCHIVE:    DW_AT_location (DW_OP_addr 0x100001004)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("baz")
+CHECK:      DW_AT_type (0x000000a7
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic2.c")
+CHECK:      DW_AT_location (DW_OP_addr 0x100001000)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("foo")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic2.c")
+CHECK:      DW_AT_type (0x000000a7
+CHECK:      DW_AT_low_pc (0x0000000100000ed0)
+CHECK:      DW_AT_high_pc (0x0000000100000f19)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("arg")
+CHECK:        DW_AT_type (0x000000a7
+CHECK:        DW_AT_location (DW_OP_fbreg -4)
+CHECK:      NULL
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("inc")
+CHECK:      DW_AT_type (0x000000a7
+CHECK:      DW_AT_low_pc (0x0000000100000f20)
+CHECK:      DW_AT_high_pc (0x0000000100000f37)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:    NULL
+
+CHECK:  Compile Unit:
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")
+CHECK:    DW_AT_name ("basic3.c")
+CHECK:    DW_AT_stmt_list (0x00000093)
+CHECK:    DW_AT_comp_dir ("/Inputs")
+CHECK:    DW_AT_low_pc (0x0000000100000f40)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("val")
+CHECK:      DW_AT_type (0x00000162
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic3.c")
+BASIC:      DW_AT_location (DW_OP_addr 0x100001004)
+ARCHIVE:    DW_AT_location (DW_OP_addr 0x100001008)
+CHECK:    DW_TAG_volatile_type
+CHECK:      DW_AT_type (0x00000167
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("int")
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("bar")
+CHECK:      DW_AT_type (0x00000167
+CHECK:      DW_AT_low_pc (0x0000000100000f40)
+CHECK:      DW_AT_high_pc (0x0000000100000f84)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("arg")
+CHECK:        DW_AT_type (0x00000167
+CHECK:        DW_AT_location (DW_OP_fbreg -8)
+CHECK:      NULL
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("inc")
+CHECK:      DW_AT_type (0x00000167
+CHECK:      DW_AT_low_pc (0x0000000100000f90)
+CHECK:      DW_AT_high_pc (0x0000000100000fa9)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+
+CHECK:    NULL
+
+CHECK-NOT: .debug_loc contents
+
+CHECK:.debug_aranges contents:
+CHECK-NEXT:Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x00000000, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT:[0x0000000100000ea0, 0x0000000100000ec4)
+CHECK-NEXT:Address Range Header: length = 0x0000003c, format = DWARF32, version = 0x0002, cu_offset = 0x00000081, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT:[0x0000000100000ed0, 0x0000000100000f19)
+CHECK-NEXT:[0x0000000100000f20, 0x0000000100000f37)
+CHECK-NEXT:Address Range Header: length = 0x0000003c, format = DWARF32, version = 0x0002, cu_offset = 0x00000126, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT:[0x0000000100000f40, 0x0000000100000f84)
+CHECK-NEXT:[0x0000000100000f90, 0x0000000100000fa9)
+
+CHECK: .debug_line contents:
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic1.c"
+CHECK-NEXT: dir_index: 0
+CHECK: Address            Line   Column File   ISA Discriminator OpIndex Flags
+CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- ------- -------------
+CHECK-NEXT: 0x0000000100000ea0     23      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000eb6     24      0      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000ec4     24      0      1   0             0       0  is_stmt end_sequence
+
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic2.c"
+CHECK-NEXT: dir_index: 0
+CHECK: Address            Line   Column File   ISA Discriminator OpIndex Flags
+CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- ------- -------------
+CHECK-NEXT: 0x0000000100000ed0     19      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000ee2     20      0      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000f19     20      0      1   0             0       0  is_stmt end_sequence
+CHECK-NEXT: 0x0000000100000f20     14      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f24     15      0      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000f37     15      0      1   0             0       0  is_stmt end_sequence
+
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic3.c"
+CHECK-NEXT: dir_index: 0
+CHECK: Address            Line   Column File   ISA Discriminator OpIndex Flags
+CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- ------- -------------
+CHECK-NEXT: 0x0000000100000f40     16      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f4b     17      0      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000f58     18      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f6c     19      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f7b     20      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f84     20      0      1   0             0       0  is_stmt end_sequence
+CHECK-NEXT: 0x0000000100000f90     11      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f9b     12      0      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000fa9     12      0      1   0             0       0  is_stmt end_sequence

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-dw4-linking-x86.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-dw4-linking-x86.test
new file mode 100644
index 00000000000000..75a85d82b4ef28
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-dw4-linking-x86.test
@@ -0,0 +1,183 @@
+RUN: dsymutil --linker llvm -f -o - -oso-prepend-path=%p/../.. %p/../../Inputs/basic-lto-dw4.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
+
+CHECK: file format Mach-O 64-bit x86-64
+
+CHECK: debug_info contents
+
+CHECK:  Compile Unit: {{.*}} version = 0x0004
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("clang version 3.7.0 ")
+CHECK:    DW_AT_language (DW_LANG_C99)
+CHECK:    DW_AT_name ("basic1.c")
+CHECK:    DW_AT_stmt_list (0x00000000)
+CHECK:    DW_AT_comp_dir ("/Inputs")
+CHECK:    DW_AT_low_pc (0x0000000100000f40)
+CHECK:    DW_AT_high_pc (0x0000000100000f4b)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_low_pc (0x0000000100000f40)
+CHECK:      DW_AT_high_pc (0x0000000100000f4b)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_AT_name ("main")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic1.c")
+CHECK:      DW_AT_prototyped (true)
+CHECK:      DW_AT_type (0x00000000000000a1
+CHECK:      DW_AT_external (true)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_location (DW_OP_reg5 RDI, DW_OP_piece 0x4)
+CHECK:        DW_AT_name ("argc")
+CHECK:        DW_AT_decl_file ("/Inputs{{[/\\]}}basic1.c")
+CHECK:        DW_AT_type (0x00000000000000a1
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_location (DW_OP_reg4 RSI)
+CHECK:        DW_AT_name ("argv")
+CHECK:        DW_AT_type (0x00000060
+CHECK:      NULL
+CHECK:    DW_TAG_pointer_type
+CHECK:       DW_AT_type (0x00000065
+CHECK:    DW_TAG_pointer_type
+CHECK:    DW_TAG_const_type
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("char")
+CHECK:      DW_AT_encoding (DW_ATE_signed_char)
+CHECK:      DW_AT_byte_size (0x01)
+CHECK:    NULL
+
+CHECK:  Compile Unit:{{.*}} version = 0x0004
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("clang version 3.7.0 ")
+CHECK:    DW_AT_language (DW_LANG_C99)
+CHECK:    DW_AT_name ("basic2.c")
+CHECK:    DW_AT_stmt_list (0x00000044)
+CHECK:    DW_AT_low_pc (0x0000000100000f50)
+CHECK:    DW_AT_high_pc (0x0000000100000f87)
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("int")
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("baz")
+CHECK:      DW_AT_location (DW_OP_addr 0x100001000)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("private_int")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic2.c")
+CHECK:      DW_AT_location (DW_OP_addr 0x100001008)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("inc")
+CHECK:      DW_AT_type (0x000000a1
+CHECK:      DW_AT_inline (DW_INL_inlined)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_low_pc (0x0000000100000f50)
+CHECK:      DW_AT_high_pc (0x0000000100000f87)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_AT_name ("foo")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic2.c")
+CHECK:      DW_AT_prototyped (true)
+CHECK:      DW_AT_type (0x000000a1
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_location (0x00000000
+CHECK:          [0x0000000100000f50, 0x0000000100000f5c): DW_OP_reg5 RDI, DW_OP_piece 0x4)
+CHECK:        DW_AT_name ("arg")
+CHECK:        DW_AT_type (0x000000a1
+CHECK:      DW_TAG_inlined_subroutine
+CHECK:        DW_AT_abstract_origin (0x000000d2 "inc")
+CHECK:        DW_AT_low_pc (0x0000000100000f61)
+CHECK:        DW_AT_high_pc (0x0000000100000f70)
+CHECK:      NULL
+CHECK:    NULL
+
+CHECK:  Compile Unit: {{.*}} version = 0x0004
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("clang version 3.7.0 ")
+CHECK:    DW_AT_name ("basic3.c")
+CHECK:    DW_AT_stmt_list (0x0000009a)
+CHECK:    DW_AT_low_pc (0x0000000100000f90)
+CHECK:    DW_AT_high_pc (0x0000000100000fb4)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("val")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic3.c")
+CHECK:      DW_AT_location (DW_OP_addr 0x100001004)
+CHECK:    DW_TAG_volatile_type
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("inc")
+CHECK:      DW_AT_inline (DW_INL_inlined)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_low_pc (0x0000000100000f90)
+CHECK:      DW_AT_high_pc (0x0000000100000fb4)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_AT_name ("bar")
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_location (0x00000025
+CHECK:          [0x0000000100000f90, 0x0000000100000f9f): DW_OP_reg5 RDI, DW_OP_piece 0x4
+CHECK:          [0x0000000100000fa9, 0x0000000100000fad): DW_OP_reg5 RDI, DW_OP_piece 0x4)
+CHECK:        DW_AT_name ("arg")
+CHECK:      DW_TAG_inlined_subroutine
+CHECK:        DW_AT_abstract_origin (0x0000015f "inc")
+CHECK:        DW_AT_ranges (0x00000000
+CHECK:           [0x0000000100000f94, 0x0000000100000f9a)
+CHECK:           [0x0000000100000f9f, 0x0000000100000fa7))
+
+CHECK:      NULL
+CHECK:    NULL
+
+
+CHECK: .debug_loc contents:
+CHECK-NEXT: 0x00000000:
+CHECK-NEXT:              (0x0000000000000000, 0x000000000000000c): DW_OP_reg5 RDI, DW_OP_piece 0x4
+CHECK-NOT: :
+CHECK:      0x00000025:
+CHECK-NEXT:              (0x0000000000000000, 0x000000000000000f): DW_OP_reg5 RDI, DW_OP_piece 0x4
+CHECK-NEXT:              (0x0000000000000019, 0x000000000000001d): DW_OP_reg5 RDI, DW_OP_piece 0x4
+
+
+CHECK: .debug_aranges contents:
+CHECK-NEXT: Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x00000000, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT: [0x0000000100000f40,  0x0000000100000f4b)
+CHECK-NEXT: Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x00000077, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT: [0x0000000100000f50, 0x0000000100000f87)
+CHECK-NEXT: Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x0000011b, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT: [0x0000000100000f90, 0x0000000100000fb4)
+
+CHECK: .debug_line contents:
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic1.c"
+CHECK-NEXT: dir_index: 0
+CHECK: Address            Line   Column File   ISA Discriminator OpIndex Flags
+CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- ------- -------------
+CHECK-NEXT: 0x0000000100000f40     26      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f44     27     10      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000f49     27      3      1   0             0       0
+CHECK-NEXT: 0x0000000100000f4b     27      3      1   0             0       0  end_sequence
+
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic2.c"
+CHECK-NEXT: dir_index: 0
+CHECK: Address            Line   Column File   ISA Discriminator OpIndex Flags
+CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- ------- -------------
+CHECK-NEXT: 0x0000000100000f50     19      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f54     20     18      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000f5a     20     17      1   0             0       0
+CHECK-NEXT: 0x0000000100000f5c     20     10      1   0             0       0
+CHECK-NEXT: 0x0000000100000f61     15     10      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f70     20     23      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f74     20     36      1   0             0       0
+CHECK-NEXT: 0x0000000100000f83     20     31      1   0             0       0
+CHECK-NEXT: 0x0000000100000f85     20      3      1   0             0       0
+CHECK-NEXT: 0x0000000100000f87     20      3      1   0             0       0  end_sequence
+
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic3.c"
+CHECK-NEXT: dir_index: 0
+CHECK: Address            Line   Column File   ISA Discriminator OpIndex Flags
+CHECK-NEXT: ------------------ ------ ------ ------ --- ------------- ------- -------------
+CHECK-NEXT: 0x0000000100000f90     16      0      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f94     12     10      1   0             0       0  is_stmt prologue_end
+CHECK-NEXT: 0x0000000100000f9a     17      7      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000f9f     12     10      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000fa7     20      1      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000fa9     19     18      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000fab     19     10      1   0             0       0
+CHECK-NEXT: 0x0000000100000fb2     20      1      1   0             0       0  is_stmt
+CHECK-NEXT: 0x0000000100000fb4     20      1      1   0             0       0  is_stmt end_sequence
+
+CHECK-NOT: .debug_pubnames contents:
+CHECK-NOT: .debug_pubtypes contents:

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-linking-x86.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-linking-x86.test
new file mode 100644
index 00000000000000..2c936530a85a10
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-lto-linking-x86.test
@@ -0,0 +1,182 @@
+RUN: dsymutil --linker llvm -f -o - -oso-prepend-path=%p/../.. %p/../../Inputs/basic-lto.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../.. -dump-debug-map %p/../../Inputs/basic-lto.macho.x86_64 | dsymutil -f -o - -y - | llvm-dwarfdump -a - | FileCheck %s
+
+CHECK: file format Mach-O 64-bit x86-64
+
+CHECK: debug_info contents
+
+CHECK:  Compile Unit:
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")
+CHECK:    DW_AT_language (DW_LANG_C99)
+CHECK:    DW_AT_name ("basic1.c")
+CHECK:    DW_AT_stmt_list (0x00000000)
+CHECK:    DW_AT_comp_dir ("/Inputs")
+CHECK:    DW_AT_low_pc (0x0000000100000f40)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("main")
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic1.c")
+CHECK:      DW_AT_decl_line (23)
+CHECK:      DW_AT_prototyped (0x01)
+CHECK:      DW_AT_type (0x00000063
+CHECK:      DW_AT_external (0x01)
+CHECK:      DW_AT_accessibility (DW_ACCESS_public)
+CHECK:      DW_AT_low_pc (0x0000000100000f40)
+CHECK:      DW_AT_high_pc (0x0000000100000f4b)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("argc")
+CHECK:        DW_AT_type (0x00000063
+CHECK:        DW_AT_location (DW_OP_reg5 RDI, DW_OP_piece 0x4)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("argv")
+CHECK:        DW_AT_type (0x0000006a
+CHECK:        DW_AT_location (DW_OP_reg4 RSI)
+CHECK:      NULL
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("int")
+CHECK:      DW_AT_encoding (DW_ATE_signed)
+CHECK:      DW_AT_byte_size (0x04)
+CHECK:    DW_TAG_pointer_type
+CHECK:      DW_AT_type (0x0000006f
+CHECK:    DW_TAG_pointer_type
+CHECK:      DW_AT_type (0x00000074
+CHECK:    DW_TAG_const_type
+CHECK:      DW_AT_type (0x00000079
+CHECK:    DW_TAG_base_type
+CHECK:      DW_AT_name ("char")
+CHECK:      DW_AT_encoding (DW_ATE_signed_char)
+CHECK:      DW_AT_byte_size (0x01)
+CHECK:    NULL
+
+CHECK:  Compile Unit:
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")
+CHECK:    DW_AT_name ("basic2.c")
+CHECK:    DW_AT_stmt_list (0x0000003e)
+CHECK:    DW_AT_comp_dir ("/Inputs")
+CHECK:   DW_AT_low_pc (0x0000000100000f50)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("private_int")
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic2.c")
+CHECK:      DW_AT_location (DW_OP_addr 0x100001008)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("baz")
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:      DW_AT_location (DW_OP_addr 0x100001000)
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("foo")
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:      DW_AT_low_pc (0x0000000100000f50)
+CHECK:      DW_AT_high_pc (0x0000000100000f89)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("arg")
+CHECK:        DW_AT_type (0x0000000000000063
+CHECK:        DW_AT_location (0x00000000
+CHECK:          [0x0000000100000f50, 0x0000000100000f5e): DW_OP_reg5 RDI, DW_OP_piece 0x4)
+CHECK:[[INC1:0x[0-9a-f]*]]{{.*}}DW_TAG_inlined_subroutine
+CHECK:        DW_AT_abstract_origin (0x00000128 "inc")
+CHECK:        DW_AT_low_pc (0x0000000100000f63)
+CHECK:        DW_AT_high_pc (0x0000000100000f72)
+CHECK:        DW_AT_call_line (20)
+CHECK:      NULL
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("inc")
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:      DW_AT_inline (DW_INL_inlined)
+CHECK:    NULL
+
+CHECK:  Compile Unit:
+
+CHECK:  DW_TAG_compile_unit
+CHECK:    DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")
+CHECK:    DW_AT_name ("basic3.c")
+CHECK:    DW_AT_stmt_list (0x0000007e)
+CHECK:    DW_AT_comp_dir ("/Inputs")
+CHECK:    DW_AT_low_pc (0x0000000100000f90)
+CHECK:    DW_TAG_variable
+CHECK:      DW_AT_name ("val")
+CHECK:      DW_AT_type (0x00000176
+CHECK:      DW_AT_decl_file ("/Inputs{{[/\\]}}basic3.c")
+CHECK:      DW_AT_location (DW_OP_addr 0x100001004)
+CHECK:    DW_TAG_volatile_type
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("bar")
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:      DW_AT_low_pc (0x0000000100000f90)
+CHECK:      DW_AT_high_pc (0x0000000100000fb4)
+CHECK:      DW_AT_frame_base (DW_OP_reg6 RBP)
+CHECK:      DW_TAG_formal_parameter
+CHECK:        DW_AT_name ("arg")
+CHECK:        DW_AT_type (0x0000000000000063
+CHECK:        DW_AT_location (0x00000025
+CHECK:          [0x0000000100000f90, 0x0000000100000f9f): DW_OP_reg5 RDI, DW_OP_piece 0x4
+CHECK:          [0x0000000100000fa9, 0x0000000100000fad): DW_OP_reg5 RDI, DW_OP_piece 0x4)
+CHECK:      DW_TAG_lexical_block
+CHECK:        DW_AT_low_pc (0x0000000100000f94)
+CHECK:        DW_AT_high_pc (0x0000000100000fa7)
+CHECK:[[INC2:0x[0-9a-f]*]]{{.*}}DW_TAG_inlined_subroutine
+CHECK:          DW_AT_abstract_origin (0x000001d4 "inc")
+CHECK:          DW_AT_ranges (0x00000000
+CHECK:             [0x0000000100000f94, 0x0000000100000f9a)
+CHECK:             [0x0000000100000f9f, 0x0000000100000fa7))
+CHECK:        NULL
+CHECK:      NULL
+CHECK:    DW_TAG_subprogram
+CHECK:      DW_AT_name ("inc")
+CHECK:      DW_AT_type (0x0000000000000063
+CHECK:    NULL
+
+CHECK: .debug_loc contents:
+CHECK-NEXT: 0x00000000:
+CHECK-NEXT:              (0x0000000000000000, 0x000000000000000e): DW_OP_reg5 RDI, DW_OP_piece 0x4
+CHECK-NOT: :
+CHECK:      0x00000025:
+CHECK-NEXT:              (0x0000000000000000, 0x000000000000000f): DW_OP_reg5 RDI, DW_OP_piece 0x4
+CHECK-NEXT:              (0x0000000000000019, 0x000000000000001d): DW_OP_reg5 RDI, DW_OP_piece 0x4
+
+CHECK: .debug_aranges contents:
+CHECK-NEXT: Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x00000000, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT: [0x0000000100000f40, 0x0000000100000f4b)
+CHECK-NEXT: Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x00000081, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT: [0x0000000100000f50, 0x0000000100000f89)
+CHECK-NEXT: Address Range Header: length = 0x0000002c, format = DWARF32, version = 0x0002, cu_offset = 0x0000013a, addr_size = 0x08, seg_size = 0x00
+CHECK-NEXT: [0x0000000100000f90, 0x0000000100000fb4)
+
+
+CHECK: .debug_line contents
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic1.c"
+CHECK-NEXT: dir_index: 0
+CHECK: 0x0000000100000f40     23      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000f44     24      0      1   0             0       0  is_stmt prologue_end
+CHECK: 0x0000000100000f4b     24      0      1   0             0       0  is_stmt end_sequence
+
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic2.c"
+CHECK-NEXT: dir_index: 0
+CHECK: 0x0000000100000f50     19      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000f54     20      0      1   0             0       0  is_stmt prologue_end
+CHECK: 0x0000000100000f63     15      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000f72     20      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000f89     20      0      1   0             0       0  is_stmt end_sequence
+
+CHECK: file_names[  1]:
+CHECK-NEXT: name: "basic3.c"
+CHECK-NEXT: dir_index: 0
+CHECK: 0x0000000100000f90     16      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000f94     12      0      1   0             0       0  is_stmt prologue_end
+CHECK: 0x0000000100000f9a     17      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000f9f     12      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000fa7     20      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000fa9     19      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000fb2     20      0      1   0             0       0  is_stmt
+CHECK: 0x0000000100000fb4     20      0      1   0             0       0  is_stmt end_sequence
+
+CHECK-NOT: .debug_pubnames contents:
+CHECK-NOT: .debug_pubtypes contents:

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-with-libfat-test.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-with-libfat-test.test
new file mode 100644
index 00000000000000..21ddd3b5d29517
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/basic-with-libfat-test.test
@@ -0,0 +1,12 @@
+RUN: cat %p/../../Inputs/basic-with-libfat-test.macho.x86_64 > %t1
+RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../.. %t1
+RUN: llvm-dwarfdump %t1.dwarf | FileCheck %s
+
+The test binary was created by force-linking the libfat-test.a fat archive
+with the basic linking test archive, like so:
+$ clang -all_load libfat-test.a libbasic.a basic1.macho.x86_64.o -Wl,-dead_strip -u _x86_64_var
+
+CHECK: DW_AT_name{{.*}}"x86_64_var"
+CHECK: DW_AT_name{{.*}}"basic2.c"
+CHECK: DW_AT_name{{.*}}"basic3.c"
+CHECK: DW_AT_name{{.*}}"basic1.c"

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/empty_range.s b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/empty_range.s
new file mode 100644
index 00000000000000..603867250d3b74
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/empty_range.s
@@ -0,0 +1,53 @@
+# This test verifies that an empty range list in the .debug_ranges section
+# doesn't crash dsymutil. As clang does not produce this kind of debug
+# info anymore, we used this hand-crafted assembly file to produce a testcase
+# Compile with:
+#        llvm-mc -triple x86_64-apple-darwin -filetype=obj -o 1.o empty_range.o
+
+# RUN: dsymutil --linker llvm -f -y %p/../dummy-debug-map.map -oso-prepend-path %p/../../Inputs/empty_range -o - | llvm-dwarfdump -debug-info - | FileCheck %s
+
+        .section	__TEXT,__text,regular,pure_instructions
+	.macosx_version_min 10, 11
+	.globl	__Z3foov
+	.align	4, 0x90
+__Z3foov:                               ## @_Z3foov
+Lfunc_begin0:
+	pushq	%rbp
+	movq	%rsp, %rbp
+	popq	%rbp
+	retq
+Lfunc_end0:
+	.section	__DWARF,__debug_abbrev,regular,debug
+Lsection_abbrev:
+	.byte	1                       ## Abbreviation Code
+	.byte	17                      ## DW_TAG_compile_unit
+	.byte	1                       ## DW_CHILDREN_yes
+	.byte	0                       ## EOM(1)
+	.byte	0                       ## EOM(2)
+	.byte	2                       ## Abbreviation Code
+	.byte	46                      ## DW_TAG_subprogram
+	.byte	0                       ## DW_CHILDREN_no
+	.byte	17                      ## DW_AT_low_pc
+	.byte	1                       ## DW_FORM_addr
+        .byte   0x55                    ## DW_AT_ranges
+        .byte   6                       ## DW_FORM_data4
+	.byte	0                       ## EOM(1)
+	.byte	0                       ## EOM(2)
+	.byte	0                       ## EOM(3)
+	.section	__DWARF,__debug_info,regular,debug
+Lsection_info:
+	.long	22                      ## Length of Unit
+	.short	2                       ## DWARF version number
+	.long	0                       ## Offset Into Abbrev. Section
+	.byte	8                       ## Address Size (in bytes)
+	.byte	1                       ## Abbrev [1]  DW_TAG_compile_unit
+	.byte	2                       ## Abbrev [2] DW_TAG_subprogram
+	.quad	Lfunc_begin0            ## DW_AT_low_pc
+        .long   0                       ## DW_AT_ranges (pointing at an empty entry)
+	.byte	0                       ## End Of Children Mark
+	.section	__DWARF,__debug_ranges,regular,debug
+Ldebug_range:
+        .long 0
+        .long 0
+
+# CHECK-NOT:  DW_TAG_compile_unit

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-1.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-1.test
new file mode 100644
index 00000000000000..dbdbb455eab16a
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-1.test
@@ -0,0 +1,36 @@
+# RUN: rm -rf %t
+# RUN: mkdir -p %t
+# RUN: llc -filetype=obj %p/../../Inputs/frame-dw2.ll -o %t/frame-dw2.o
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%t -y %s -o - | \
+# RUN:   llvm-dwarfdump -debug-frame - | FileCheck %s
+
+# This test is meant to verify that identical CIEs will get reused
+# in the same file but not inbetween files. For this to happen, we
+# link twice the same file using this made-up debug map:
+
+---
+triple:          'i386-apple-darwin'
+objects:
+  - filename: frame-dw2.o
+    symbols:
+      - { sym: _bar, objAddr: 0x0, binAddr: 0x1000, size: 0x12 }
+      - { sym: _baz, objAddr: 0x0, binAddr: 0x2000, size: 0x12 }
+  - filename: frame-dw2.o
+    symbols:
+      - { sym: _bar, objAddr: 0x0, binAddr: 0x3000, size: 0x12 }
+      - { sym: _baz, objAddr: 0x0, binAddr: 0x4000, size: 0x12 }
+...
+
+# CHECK: .debug_frame contents:
+# CHECK: 00000000 {{[0-9a-f]*}} ffffffff CIE
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=00000000 pc=00001000...00001
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=00000000 pc=00002000...00002
+# CHECK:  [[CIECU2:[0-9a-f]*]] {{[0-9a-f]*}} ffffffff CIE
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=[[CIECU2]] pc=00003000...00003
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=[[CIECU2]] pc=00004000...00004
+# CHECK-NOT: FDE
+# CHECK: .eh_frame contents:

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-2.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-2.test
new file mode 100644
index 00000000000000..ffb559050dabbd
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/frame-2.test
@@ -0,0 +1,46 @@
+# RUN: rm -rf %t
+# RUN: mkdir -p %t
+# RUN: llc -filetype=obj %p/../../Inputs/frame-dw2.ll -o %t/frame-dw2.o
+# RUN: llc -filetype=obj %p/../../Inputs/frame-dw4.ll -o %t/frame-dw4.o
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%t -y %s -o - | \
+# RUN:   llvm-dwarfdump -debug-frame - | FileCheck %s
+
+# Check the handling of multiple 
diff erent CIEs. To have CIEs that
+# appear to be 
diff erent, use a dwarf2 version of the file along with
+# a dwarf 4 version. The CIE header version (and layout) will be 
diff erent.
+---
+triple:          'i386-apple-darwin'
+objects:
+  - filename: frame-dw2.o
+    symbols:
+      - { sym: _bar, objAddr: 0x0, binAddr: 0x1000, size: 0x12 }
+      - { sym: _baz, objAddr: 0x0, binAddr: 0x2000, size: 0x12 }
+  - filename: frame-dw4.o
+    symbols:
+      - { sym: _baz, objAddr: 0x0, binAddr: 0x3000, size: 0x12 }
+  - filename: frame-dw2.o
+    symbols:
+      - { sym: _bar, objAddr: 0x0, binAddr: 0x4000, size: 0x12 }
+...
+
+# CHECK: .debug_frame contents:
+# CHECK: 00000000 {{[0-9a-f]*}} ffffffff CIE
+# CHECK-NEXT: Format: DWARF32
+# CHECK-NEXT: Version:{{.*}}1
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=00000000 pc=00001000...00001
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=00000000 pc=00002000...00002
+# CHECK-NOT: FDE
+# CHECK: [[CIEDW4:[0-9a-f]*]] 00000010 ffffffff CIE
+# CHECK-NEXT: Format: DWARF32
+# CHECK-NEXT: Version:{{.*}}4
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=[[CIEDW4]] pc=00003000...00003
+# CHECK: [[CIEDW1_2:[0-9a-f]*]] 00000010 ffffffff CIE
+# CHECK-NEXT: Format: DWARF32
+# CHECK-NEXT: Version:{{.*}}1
+# CHECK-NOT: FDE
+# CHECK:  FDE cie=[[CIEDW1_2]] pc=00004000...00004
+# CHECK-NOT: FDE
+# CHECK: .eh_frame contents:

diff  --git a/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/multiple-inputs.test b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/multiple-inputs.test
new file mode 100644
index 00000000000000..9adcdcbc4ba719
--- /dev/null
+++ b/llvm/test/tools/dsymutil/X86/DWARFLinkerParallel/multiple-inputs.test
@@ -0,0 +1,30 @@
+RUN: rm -rf %t
+RUN: mkdir -p %t
+
+RUN: cat %p/../../Inputs/basic.macho.x86_64 > %t/basic.macho.x86_64
+RUN: cat %p/../../Inputs/basic-archive.macho.x86_64 > %t/basic-archive.macho.x86_64
+RUN: cat %p/../../Inputs/basic-lto.macho.x86_64 > %t/basic-lto.macho.x86_64
+RUN: cat %p/../../Inputs/basic-lto-dw4.macho.x86_64 > %t/basic-lto-dw4.macho.x86_64
+
+# Multiple inputs in flat mode
+RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../.. %t/basic.macho.x86_64 %t/basic-archive.macho.x86_64 %t/basic-lto.macho.x86_64 %t/basic-lto-dw4.macho.x86_64
+RUN: llvm-dwarfdump -a %t/basic.macho.x86_64.dwarf \
+RUN: | FileCheck %S/basic-linking-x86.test --check-prefixes=CHECK,BASIC
+RUN: llvm-dwarfdump -a %t/basic-archive.macho.x86_64.dwarf \
+RUN: | FileCheck %S/basic-linking-x86.test --check-prefixes=CHECK,ARCHIVE
+RUN: llvm-dwarfdump -a %t/basic-lto.macho.x86_64.dwarf | FileCheck %S/basic-lto-linking-x86.test
+RUN: llvm-dwarfdump -a %t/basic-lto-dw4.macho.x86_64.dwarf | FileCheck %S/basic-lto-dw4-linking-x86.test
+
+# Multiple inputs that end up in the same named bundle
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../.. %t/basic.macho.x86_64 %t/basic-archive.macho.x86_64 %t/basic-lto.macho.x86_64 %t/basic-lto-dw4.macho.x86_64 -o %t.dSYM
+RUN: llvm-dwarfdump -a %t.dSYM/Contents/Resources/DWARF/basic.macho.x86_64 \
+RUN: | FileCheck %S/basic-linking-x86.test --check-prefixes=CHECK,BASIC
+RUN: llvm-dwarfdump -a %t.dSYM/Contents/Resources/DWARF/basic-archive.macho.x86_64 \
+RUN: | FileCheck %S/basic-linking-x86.test --check-prefixes=CHECK,ARCHIVE
+RUN: llvm-dwarfdump -a %t.dSYM/Contents/Resources/DWARF/basic-lto.macho.x86_64 | FileCheck %S/basic-lto-linking-x86.test
+RUN: llvm-dwarfdump -a %t.dSYM/Contents/Resources/DWARF/basic-lto-dw4.macho.x86_64 | FileCheck %S/basic-lto-dw4-linking-x86.test
+
+# Multiple inputs in a named bundle in flat mode... impossible.
+RUN: not dsymutil --linker llvm -f -oso-prepend-path=%p/../.. %t/basic.macho.x86_64 %t/basic-archive.macho.x86_64 %t/basic-lto.macho.x86_64 %t/basic-lto-dw4.macho.x86_64 -o %t.dSYM 2>&1 | FileCheck %s
+
+CHECK: error: cannot use -o with multiple inputs in flat mode

diff  --git a/llvm/test/tools/dsymutil/X86/alias.test b/llvm/test/tools/dsymutil/X86/alias.test
index 2e56ba5719b158..4c1e8168706098 100644
--- a/llvm/test/tools/dsymutil/X86/alias.test
+++ b/llvm/test/tools/dsymutil/X86/alias.test
@@ -1,5 +1,9 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs/alias \
 # RUN: %p/../Inputs/alias/foobar -o - | llvm-dwarfdump - 2>&1 | FileCheck %s
+
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs/alias \
+# RUN: %p/../Inputs/alias/foobar -o - | llvm-dwarfdump - 2>&1 | FileCheck %s
+
 # CHECK-NOT: could not find object file symbol for symbol
 # CHECK: DW_AT_name ("foo.c")
 # CHECK: DW_AT_name ("bar.c")

diff  --git a/llvm/test/tools/dsymutil/X86/call-site-entry-linking.test b/llvm/test/tools/dsymutil/X86/call-site-entry-linking.test
index 7eef7af41f5252..2ef400f5d7120f 100644
--- a/llvm/test/tools/dsymutil/X86/call-site-entry-linking.test
+++ b/llvm/test/tools/dsymutil/X86/call-site-entry-linking.test
@@ -1,4 +1,7 @@
 RUN: dsymutil -oso-prepend-path=%p %p/Inputs/call-site-entry.macho.x86_64 -o %t.dSYM
 RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p %p/Inputs/call-site-entry.macho.x86_64 -o %t.dSYM
+RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
+
 CHECK: DW_AT_call_return_pc  (0x0000000100000fa4)

diff  --git a/llvm/test/tools/dsymutil/X86/call-site-entry-reloc.test b/llvm/test/tools/dsymutil/X86/call-site-entry-reloc.test
index 46e947044ffcaa..a03ce06d6545b7 100644
--- a/llvm/test/tools/dsymutil/X86/call-site-entry-reloc.test
+++ b/llvm/test/tools/dsymutil/X86/call-site-entry-reloc.test
@@ -22,5 +22,8 @@ twice.
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/call_return_pc/call -o %t.dSYM
 RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/call_return_pc/call -o %t.dSYM
+RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
+
 CHECK: DW_AT_call_return_pc  (0x0000000100000f72)
 CHECK: DW_AT_call_return_pc  (0x0000000100000f78)

diff  --git a/llvm/test/tools/dsymutil/X86/common-sym-multi.test b/llvm/test/tools/dsymutil/X86/common-sym-multi.test
index ff970a53bfecf0..9ce14bb541c2ee 100644
--- a/llvm/test/tools/dsymutil/X86/common-sym-multi.test
+++ b/llvm/test/tools/dsymutil/X86/common-sym-multi.test
@@ -1,6 +1,9 @@
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/common/common.x86_64 -f -o - | llvm-dwarfdump -debug-info - | FileCheck %s
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/common/common.x86_64 -dump-debug-map | FileCheck %s --check-prefix DEBUGMAP
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/common/common.x86_64 -f -o - | llvm-dwarfdump -debug-info - | FileCheck %s
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/common/common.x86_64 -dump-debug-map | FileCheck %s --check-prefix DEBUGMAP
+
 The test was compiled from two source files:
 $ cd /private/tmp/common
 $ cat common1.c

diff  --git a/llvm/test/tools/dsymutil/X86/common-sym.test b/llvm/test/tools/dsymutil/X86/common-sym.test
index 0f07c8f39b81aa..796866c4743caa 100644
--- a/llvm/test/tools/dsymutil/X86/common-sym.test
+++ b/llvm/test/tools/dsymutil/X86/common-sym.test
@@ -1,5 +1,7 @@
 RUN: dsymutil -oso-prepend-path %p/.. %p/../Inputs/common.macho.x86_64 -f -o - | llvm-dwarfdump -v -debug-info - | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/.. %p/../Inputs/common.macho.x86_64 -f -o - | llvm-dwarfdump -v -debug-info - | FileCheck %s
+
 The test was compiled from a single source:
 $ cat common.c 
 char common[16];

diff  --git a/llvm/test/tools/dsymutil/X86/custom-line-table.test b/llvm/test/tools/dsymutil/X86/custom-line-table.test
index f75e01a12fba9c..8a164655ec21a3 100644
--- a/llvm/test/tools/dsymutil/X86/custom-line-table.test
+++ b/llvm/test/tools/dsymutil/X86/custom-line-table.test
@@ -1,4 +1,6 @@
 # RUN: dsymutil -oso-prepend-path %p/../Inputs -y %s -f -o - | llvm-dwarfdump - --debug-line | FileCheck %s
+#
+# RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs -y %s -f -o - | llvm-dwarfdump - --debug-line | FileCheck %s
 
 # This test runs dsymutil on an object file with non-standard (as far
 # as llvm is concerned) line table settings.

diff  --git a/llvm/test/tools/dsymutil/X86/darwin-bundle.test b/llvm/test/tools/dsymutil/X86/darwin-bundle.test
index d44b25e4870545..80a42217edff19 100644
--- a/llvm/test/tools/dsymutil/X86/darwin-bundle.test
+++ b/llvm/test/tools/dsymutil/X86/darwin-bundle.test
@@ -11,6 +11,13 @@ RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info
 RUN: dsymutil -oso-prepend-path=%p/.. %t/basic.macho.x86_64 -toolchain "toolchain&and'some<symbols" -o %t/dsymdest/basic.macho.x86_64.dSYM
 RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info.plist --check-prefix=CHECK --check-prefix=TOOLCHAIN
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/.. %t/basic.macho.x86_64 -o %t/dsymdest/basic.macho.x86_64.dSYM
+RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info.plist
+
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/.. %t/basic.macho.x86_64 -toolchain "toolchain&and'some<symbols" -o %t/dsymdest/basic.macho.x86_64.dSYM
+RUN: FileCheck %s --input-file %t/dsymdest/basic.macho.x86_64.dSYM/Contents/Info.plist --check-prefix=CHECK --check-prefix=TOOLCHAIN
+
+
 CHECK: <?xml version="1.0" encoding="UTF-8"?>
 CHECK-NEXT: <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 CHECK-NEXT: <plist version="1.0">

diff  --git a/llvm/test/tools/dsymutil/X86/dead-stripped.cpp b/llvm/test/tools/dsymutil/X86/dead-stripped.cpp
index 6ea5ef22a65acb..8a72aee6fb38fb 100644
--- a/llvm/test/tools/dsymutil/X86/dead-stripped.cpp
+++ b/llvm/test/tools/dsymutil/X86/dead-stripped.cpp
@@ -1,5 +1,10 @@
 // RUN: dsymutil -f -y %p/dummy-debug-map.map -oso-prepend-path %p/../Inputs/dead-stripped -o - | llvm-dwarfdump - --debug-info | FileCheck %s --implicit-check-not "{{DW_AT_low_pc|DW_AT_high_pc|DW_AT_location|DW_TAG|NULL}}"
 
+// RUN: dsymutil --linker llvm -f -y %p/dummy-debug-map.map -oso-prepend-path \
+// RUN: %p/../Inputs/dead-stripped -o - | llvm-dwarfdump - --debug-info | \
+// RUN: FileCheck %s --implicit-check-not \
+// RUN: "{{DW_AT_low_pc|DW_AT_high_pc|DW_AT_location|DW_TAG|NULL}}"
+
 // The test was compiled with:
 // clang++ -O2 -g -c dead-strip.cpp -o 1.o
 

diff  --git a/llvm/test/tools/dsymutil/X86/debug-loc-base-addr.test b/llvm/test/tools/dsymutil/X86/debug-loc-base-addr.test
index a36e9139bcf0b7..341f64dec4090e 100644
--- a/llvm/test/tools/dsymutil/X86/debug-loc-base-addr.test
+++ b/llvm/test/tools/dsymutil/X86/debug-loc-base-addr.test
@@ -1,5 +1,7 @@
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/baseaddr/loc1.x86_64 -f -o - | llvm-dwarfdump --debug-info - | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/baseaddr/loc1.x86_64 -f -o - | llvm-dwarfdump --debug-info - | FileCheck %s
+
 The test was compiled from a single source:
 $ cat loc1.cpp
 int f1(int i, int j) {

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf4-linetable.test b/llvm/test/tools/dsymutil/X86/dwarf4-linetable.test
index 4de68abbf062ed..eb3e8fb2a714b9 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf4-linetable.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf4-linetable.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs/ -y %s -o - | llvm-dwarfdump -debug-line - | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs/ -y %s -o - | llvm-dwarfdump -debug-line - | FileCheck %s
+
 # Source:
 #   int main() {
 #     return 0;

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf5-addrx.test b/llvm/test/tools/dsymutil/X86/dwarf5-addrx.test
index 463c51a1b068ee..fd6197bdc5fb42 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf5-addrx.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-addrx.test
@@ -52,6 +52,17 @@ RUN: llvm-dwarfdump --verify %t.dSYM 2>&1 | FileCheck %s
 
 RUN: llvm-dwarfdump --verbose %t.dSYM | FileCheck %s --check-prefix UPDATE-DWARF
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/dwarf5/dwarf5-addrx.out -o %t.dSYM 2>&1 | FileCheck %s --allow-empty
+RUN: llvm-dwarfdump --verify %t.dSYM 2>&1 | FileCheck %s
+
+RUN: llvm-dwarfdump --verbose %t.dSYM | FileCheck %s --check-prefix DWARF
+
+RUN: dsymutil --linker llvm --update -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/dwarf5/dwarf5-addrx.out -o %t.dSYM 2>&1 | FileCheck %s --allow-empty
+RUN: llvm-dwarfdump --verify %t.dSYM 2>&1 | FileCheck %s
+
+RUN: llvm-dwarfdump --verbose %t.dSYM | FileCheck %s --check-prefix UPDATE-DWARF
+
+
 CHECK-NOT: error:
 
 DWARF: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf5-call-site-entry-reloc.test b/llvm/test/tools/dsymutil/X86/dwarf5-call-site-entry-reloc.test
index b960d4496ce7d7..bc17a456b2b4c0 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf5-call-site-entry-reloc.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-call-site-entry-reloc.test
@@ -22,6 +22,9 @@
 #RUN: dsymutil -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
 #RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
 
+#RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_return_pc
+
 #CHECK: DW_AT_call_return_pc  (0x0000000100000f72)
 #CHECK: DW_AT_call_return_pc  (0x0000000100000f78)
 

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf5-dw-op-addrx.test b/llvm/test/tools/dsymutil/X86/dwarf5-dw-op-addrx.test
index 34100145b17de6..f78a3102e18a5e 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf5-dw-op-addrx.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-dw-op-addrx.test
@@ -25,6 +25,14 @@
 #RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
 #RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+#RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
+#RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix DWARF-CHECK
+
+#RUN: dsymutil --linker llvm --update -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
+#RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 #CHECK: No errors.
 
 #DWARF-CHECK: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf5-linetable.test b/llvm/test/tools/dsymutil/X86/dwarf5-linetable.test
index 008e133ec63015..a07e13038e94ba 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf5-linetable.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-linetable.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs/ -y %s -o - | llvm-dwarfdump -debug-line -debug-line-str --verbose - | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs/ -y %s -o - | llvm-dwarfdump -debug-line -debug-line-str --verbose - | FileCheck %s
+
 # Source:
 #   int main() {
 #     return 0;

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf5-loclists.test b/llvm/test/tools/dsymutil/X86/dwarf5-loclists.test
index ccb458c35c41aa..f7133d638d32b6 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf5-loclists.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-loclists.test
@@ -24,6 +24,14 @@
 #RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
 #RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+#RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
+#RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix DWARF-CHECK
+
+#RUN: dsymutil --linker llvm --update -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
+#RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 #CHECK: No errors.
 
 #DWARF-CHECK: DW_TAG_formal_parameter

diff  --git a/llvm/test/tools/dsymutil/X86/dwarf5-rnglists.test b/llvm/test/tools/dsymutil/X86/dwarf5-rnglists.test
index 7603ae738f8e8a..b6d2f4391c70e3 100644
--- a/llvm/test/tools/dsymutil/X86/dwarf5-rnglists.test
+++ b/llvm/test/tools/dsymutil/X86/dwarf5-rnglists.test
@@ -32,11 +32,19 @@
 #RUN: dsymutil -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
 #RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
 #RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix DWARF-CHECK
-#
+
 #RUN: dsymutil --update -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
 #RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
 #RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+#RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
+#RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix DWARF-CHECK
+
+#RUN: dsymutil --linker llvm --update -oso-prepend-path %p/../Inputs -y %s -o %t.dSYM
+#RUN: llvm-dwarfdump --verify  %t.dSYM | FileCheck %s
+#RUN: llvm-dwarfdump -a --verbose  %t.dSYM | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 #CHECK: No errors.
 
 #DWARF-CHECK: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/dsymutil/X86/eh_frame.test b/llvm/test/tools/dsymutil/X86/eh_frame.test
index c4be843fff597c..08e403eedfb41c 100644
--- a/llvm/test/tools/dsymutil/X86/eh_frame.test
+++ b/llvm/test/tools/dsymutil/X86/eh_frame.test
@@ -18,5 +18,10 @@ RUN: llvm-dwarfdump --verify %t.dSYM
 RUN: llvm-otool -s __TEXT __eh_frame %p/../Inputs/private/tmp/eh_frame/eh_frame.out | FileCheck %s
 RUN: llvm-otool -s __TEXT __eh_frame %t.dSYM/Contents/Resources/DWARF/eh_frame.out | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/eh_frame/eh_frame.out -o %t.dSYM
+RUN: llvm-dwarfdump --verify %t.dSYM
+RUN: llvm-otool -s __TEXT __eh_frame %p/../Inputs/private/tmp/eh_frame/eh_frame.out | FileCheck %s
+RUN: llvm-otool -s __TEXT __eh_frame %t.dSYM/Contents/Resources/DWARF/eh_frame.out | FileCheck %s
+
 CHECK: 14 00 00 00 00 00 00 00 01 7a 52 00 01 78 10 01
 CHECK: 10 0c 07 08 90 01 00 00

diff  --git a/llvm/test/tools/dsymutil/X86/empty-CU.test b/llvm/test/tools/dsymutil/X86/empty-CU.test
index 7b06607a74cbc0..db9f70874971b3 100644
--- a/llvm/test/tools/dsymutil/X86/empty-CU.test
+++ b/llvm/test/tools/dsymutil/X86/empty-CU.test
@@ -1,6 +1,8 @@
 RUN: llvm-mc %p/../Inputs/empty-CU.s -filetype obj -triple x86_64-apple-darwin -o %t.o
 RUN: dsymutil --update -f %t.o -o - | llvm-dwarfdump -v - -debug-info | FileCheck %s
 
+RUN: dsymutil --linker llvm --update -f %t.o -o - | llvm-dwarfdump -v - -debug-info | FileCheck %s
+
 CHECK: .debug_info contents:
 CHECK: 0x00000000: Compile Unit: length = 0x00000008, format = DWARF32, version = 0x0003, abbr_offset = 0x0000, addr_size = 0x04 (next unit at 0x0000000c)
 

diff  --git a/llvm/test/tools/dsymutil/X86/fat-archive-input-i386.test b/llvm/test/tools/dsymutil/X86/fat-archive-input-i386.test
index 5c71f130a7f70f..a2d165500b9fe2 100644
--- a/llvm/test/tools/dsymutil/X86/fat-archive-input-i386.test
+++ b/llvm/test/tools/dsymutil/X86/fat-archive-input-i386.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
+
 ---
 triple:          'i386-apple-darwin'
 objects:

diff  --git a/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64.test b/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64.test
index d6cb6714be6e5a..6259d11a3358fa 100644
--- a/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64.test
+++ b/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
+
 ---
 triple:          'x86_64-apple-darwin'
 objects:

diff  --git a/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64h.test b/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64h.test
index d7200c8647cf04..588fee9bb10928 100644
--- a/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64h.test
+++ b/llvm/test/tools/dsymutil/X86/fat-object-input-x86_64h.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -f -oso-prepend-path=%p/../Inputs -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -oso-prepend-path=%p/../Inputs -y %s -o - | llvm-dwarfdump -debug-info - | FileCheck %s
+
 ---
 triple:          'x86_64h-apple-darwin'
 objects:

diff  --git a/llvm/test/tools/dsymutil/X86/generate-empty-CU.test b/llvm/test/tools/dsymutil/X86/generate-empty-CU.test
index 58afea183a2f05..aa70ca7de98b75 100644
--- a/llvm/test/tools/dsymutil/X86/generate-empty-CU.test
+++ b/llvm/test/tools/dsymutil/X86/generate-empty-CU.test
@@ -1,7 +1,9 @@
 # RUN: dsymutil -f -o - -oso-prepend-path=%p/.. -y %s | llvm-dwarfdump -v - | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -o - -oso-prepend-path=%p/.. -y %s | llvm-dwarfdump -v - | FileCheck %s
+
 # This test on links the Dwarf for an LTO binary and on purpose doesn't retain
-# any symbol in the second CU out of 3. To be valid DWARF ssymutil must not
+# any symbol in the second CU out of 3. To be valid DWARF dsymutil must not
 # generate an empty CU but omit it.
 
 ---
@@ -22,10 +24,12 @@ CHECK:        DW_AT_name {{.*}} "basic1.c"
 CHECK:   DW_TAG_subprogram
                 DW_AT_name {{.*}} "main"
 
-CHECK: 0x00000081: Compile Unit: length = 0x00000089, format = DWARF32, version = 0x0002, abbr_offset = 0x0000, addr_size = 0x08 (next unit at 0x0000010e)
+CHECK: 0x00000081: Compile Unit: length = 0x00000089, format = DWARF32, version = 0x0002, abbr_offset = 0x00{{00|53}}, addr_size = 0x08 (next unit at 0x0000010e)
 
 CHECK: DW_TAG_compile_unit
 CHECK:        DW_AT_name {{.*}} "basic3.c"
 
-CHECK:   DW_TAG_subprogram [7] *
+CHECK:   DW_TAG_subprogram
 CHECK:          DW_AT_name {{.*}} = "bar"
+
+CHECK-NOT: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/dsymutil/X86/global_downgraded_to_static.c b/llvm/test/tools/dsymutil/X86/global_downgraded_to_static.c
index 0c808a208fe9cb..28910cb0d34147 100644
--- a/llvm/test/tools/dsymutil/X86/global_downgraded_to_static.c
+++ b/llvm/test/tools/dsymutil/X86/global_downgraded_to_static.c
@@ -1,5 +1,9 @@
 // REQUIRES : system-darwin
-// RUN: dsymutil -oso-prepend-path %p/.. -dump-debug-map %p/../Inputs/global_downgraded_to_static.x86_64 2>&1 | FileCheck %s
+// RUN: dsymutil -oso-prepend-path %p/.. -dump-debug-map \
+// RUN: %p/../Inputs/global_downgraded_to_static.x86_64 2>&1 | FileCheck %s
+//
+// RUN: dsymutil --linker llvm -oso-prepend-path %p/.. -dump-debug-map \
+// RUN: %p/../Inputs/global_downgraded_to_static.x86_64 2>&1 | FileCheck %s
 //
 //  To build:
 //    clang -g -c -DFILE1 global_downgraded_to_static.c -o 1.o

diff  --git a/llvm/test/tools/dsymutil/X86/inlined-static-variable.cpp b/llvm/test/tools/dsymutil/X86/inlined-static-variable.cpp
index 5593b2638147e4..e933be8fd9bdb0 100644
--- a/llvm/test/tools/dsymutil/X86/inlined-static-variable.cpp
+++ b/llvm/test/tools/dsymutil/X86/inlined-static-variable.cpp
@@ -1,5 +1,10 @@
 // RUN: dsymutil -f -y %p/dummy-debug-map.map -oso-prepend-path %p/../Inputs/inlined-static-variable -o - | llvm-dwarfdump - | FileCheck %s --implicit-check-not "{{DW_AT_low_pc|DW_AT_high_pc|DW_AT_location|DW_TAG|NULL}}"
 
+// RUN: dsymutil --linker llvm -f -y %p/dummy-debug-map.map -oso-prepend-path \
+// RUN: %p/../Inputs/inlined-static-variable -o - | llvm-dwarfdump - | \
+// RUN: FileCheck %s --implicit-check-not \
+// RUN: "{{DW_AT_low_pc|DW_AT_high_pc|DW_AT_location|DW_TAG|NULL}}"
+
 // clang -g -c inlined-static-variable.cpp -o 4.o
 
 // The functions removed and not_removed are not in the debug map and are

diff  --git a/llvm/test/tools/dsymutil/X86/keep-func.test b/llvm/test/tools/dsymutil/X86/keep-func.test
index 021c7212bd8319..f307f5ad89900d 100644
--- a/llvm/test/tools/dsymutil/X86/keep-func.test
+++ b/llvm/test/tools/dsymutil/X86/keep-func.test
@@ -25,6 +25,11 @@ RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/keep_func/
 RUN: llvm-dwarfdump %t.omit.dSYM | FileCheck %s --check-prefix OMIT
 RUN: llvm-dwarfdump %t.keep.dSYM | FileCheck %s --check-prefix KEEP
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/keep_func/main.out -o %t.omit.dSYM
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/keep_func/main.out -o %t.keep.dSYM -keep-function-for-static
+RUN: llvm-dwarfdump %t.omit.dSYM | FileCheck %s --check-prefix OMIT
+RUN: llvm-dwarfdump %t.keep.dSYM | FileCheck %s --check-prefix KEEP
+
 KEEP:     DW_AT_name	("MyDummyVar")
 KEEP:     DW_AT_name	("FOO_VAR_TYPE")
 KEEP:     DW_AT_name	("x1")

diff  --git a/llvm/test/tools/dsymutil/X86/label.test b/llvm/test/tools/dsymutil/X86/label.test
index 62c9d62b76b176..129f603781e51e 100644
--- a/llvm/test/tools/dsymutil/X86/label.test
+++ b/llvm/test/tools/dsymutil/X86/label.test
@@ -1,5 +1,7 @@
 # RUN: dsymutil -oso-prepend-path %p/../Inputs -y %s -f -o - | llvm-dwarfdump - --debug-info | FileCheck %s
 
+# RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs -y %s -f -o - | llvm-dwarfdump - --debug-info | FileCheck %s
+
 # Compile with:
 #  echo -e ".global _foo;\nfoo:\nnop" | clang -x assembler -g - -c -o /tmp/label.o
 

diff  --git a/llvm/test/tools/dsymutil/X86/label2.test b/llvm/test/tools/dsymutil/X86/label2.test
index 0517d1e7135b50..9e0f39e5f337b4 100644
--- a/llvm/test/tools/dsymutil/X86/label2.test
+++ b/llvm/test/tools/dsymutil/X86/label2.test
@@ -14,6 +14,9 @@ $ clang label.o -o label.out
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/label/label.out -o %t.dSYM
 RUN: llvm-dwarfdump %t.dSYM | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/label/label.out -o %t.dSYM
+RUN: llvm-dwarfdump %t.dSYM | FileCheck %s
+
 CHECK:      DW_TAG_label
 CHECK-NEXT:   DW_AT_name    ("foobar")
 CHECK-NEXT:   DW_AT_decl_file       ("/tmp/label{{[/\\]}}label.c")

diff  --git a/llvm/test/tools/dsymutil/X86/lc_build_version.test b/llvm/test/tools/dsymutil/X86/lc_build_version.test
index 2c91cbb0aa0e5c..f0d0e803b7a3b2 100644
--- a/llvm/test/tools/dsymutil/X86/lc_build_version.test
+++ b/llvm/test/tools/dsymutil/X86/lc_build_version.test
@@ -1,6 +1,9 @@
 # RUN: dsymutil -f %p/../Inputs/lc_build_version.x86_64 -o - \
 # RUN:   -oso-prepend-path=%p/.. | obj2yaml | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f %p/../Inputs/lc_build_version.x86_64 -o - \
+# RUN:   -oso-prepend-path=%p/.. | obj2yaml | FileCheck %s
+
 CHECK: LoadCommands:
 CHECK:   - cmd:             LC_BUILD_VERSION
 CHECK-NEXT:    cmdsize:         24

diff  --git a/llvm/test/tools/dsymutil/X86/location-expression.test b/llvm/test/tools/dsymutil/X86/location-expression.test
index a991edb6b75f75..5414dff3745b28 100644
--- a/llvm/test/tools/dsymutil/X86/location-expression.test
+++ b/llvm/test/tools/dsymutil/X86/location-expression.test
@@ -11,6 +11,7 @@
 # RUN: echo '      - { sym: __Z3foov, objAddr: 0x0, binAddr: 0x10000, size: 0x10 }' >> %t2.map
 # RUN: echo '...' >> %t2.map
 # RUN: dsymutil -y %t2.map -f -o - | llvm-dwarfdump -a --verbose - | FileCheck %s
+# RUN: dsymutil --linker llvm -y %t2.map -f -o - | llvm-dwarfdump -a --verbose - | FileCheck %s
 
 # CHECK: file format Mach-O 64-bit x86-64
 # CHECK: .debug_info contents:
@@ -20,11 +21,11 @@
 # CHECK: 0x0000001b:   DW_TAG_variable
 # CHECK: DW_AT_name {{.*}}"var1"
 # CHECK: DW_AT_type {{.*}}"class1"
-# CHECK:   DW_AT_location [DW_FORM_block1]  (DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address)
+# CHECK:   DW_AT_location [DW_FORM_block1]  (DW_OP_const8u 0x{{.*}}, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address)
 # CHECK: 0x000000ab:   DW_TAG_variable
 # CHECK: DW_AT_name {{.*}}"var2"
 # CHECK: DW_AT_type {{.*}}"class1"
-# CHECK:   DW_AT_location [DW_FORM_block]  (DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address)
+# CHECK:   DW_AT_location [DW_FORM_block]  (DW_OP_const8u 0x{{.*}}, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address, DW_OP_const8u 0x2000, DW_OP_form_tls_address)
 # CHECK: 0x00000146:   DW_TAG_variable
 # CHECK: DW_AT_name {{.*}}"var3"
 # CHECK: DW_AT_type {{.*}}"class1"
@@ -72,13 +73,21 @@ LoadCommands:
         offset:    0x00000410
         align:     0
         reloff:    0x00000600
-        nreloc:    1
+        nreloc:    2
         flags:     0x02000000
         reserved1: 0x00000000
         reserved2: 0x00000000
         reserved3: 0x00000000
         relocations:
-          - address:         0x1FC
+          - address:         0x30
+            symbolnum:       1
+            pcrel:           true
+            length:          3
+            extern:          true
+            type:            0
+            scattered:       false
+            value:           0
+          - address:         0xc2
             symbolnum:       1
             pcrel:           true
             length:          3

diff  --git a/llvm/test/tools/dsymutil/X86/mismatch.m b/llvm/test/tools/dsymutil/X86/mismatch.m
index 2e907530c5b1c8..d2d257a54c777b 100644
--- a/llvm/test/tools/dsymutil/X86/mismatch.m
+++ b/llvm/test/tools/dsymutil/X86/mismatch.m
@@ -19,6 +19,8 @@
 // RUN: cp %p/../Inputs/mismatch/1.o %t.dir/2.o
 // RUN: dsymutil --verbose -f -oso-prepend-path=%t.dir \
 // RUN:   -y %p/dummy-debug-map.map -o %t.bin 2>&1 | FileCheck %s
+// RUN: dsymutil --linker llvm --verbose -f -oso-prepend-path=%t.dir \
+// RUN:   -y %p/dummy-debug-map.map -o %t.bin 2>&1 | FileCheck %s
 
 @import mismatch;
 

diff  --git a/llvm/test/tools/dsymutil/X86/modules-dwarf-version.m b/llvm/test/tools/dsymutil/X86/modules-dwarf-version.m
index 7c395f22e5168d..b57e91adb8b86a 100644
--- a/llvm/test/tools/dsymutil/X86/modules-dwarf-version.m
+++ b/llvm/test/tools/dsymutil/X86/modules-dwarf-version.m
@@ -11,6 +11,9 @@
 // RUN: dsymutil -verify -f -oso-prepend-path=%t.dir \
 // RUN:   -y %p/dummy-debug-map.map -o - \
 // RUN:     | llvm-dwarfdump --debug-info - | FileCheck %s
+// RUN: dsymutil --linker llvm -verify -f -oso-prepend-path=%t.dir \
+// RUN:   -y %p/dummy-debug-map.map -o - \
+// RUN:     | llvm-dwarfdump --debug-info - | FileCheck %s
 
 @import Bar;
 int main(int argc, char **argv) {

diff  --git a/llvm/test/tools/dsymutil/X86/modules-empty.m b/llvm/test/tools/dsymutil/X86/modules-empty.m
index ce5ab427af57d3..fc415acc59f6d6 100644
--- a/llvm/test/tools/dsymutil/X86/modules-empty.m
+++ b/llvm/test/tools/dsymutil/X86/modules-empty.m
@@ -12,11 +12,16 @@
 
 // RUN: rm -rf %t.dir
 // RUN: mkdir %t.dir
-// RUN: cp %p/../Inputs/modules-empty/1.o %p/../Inputs/modules-empty/Empty.pcm %t.dir
+// RUN: cp %p/../Inputs/modules-empty/1.o %p/../Inputs/modules-empty/Empty.pcm \
+// RUN: %t.dir
 // RUN: dsymutil -f -oso-prepend-path=%t.dir \
 // RUN:   -verify \
 // RUN:   -y %p/dummy-debug-map.map -o - \
 // RUN:     | llvm-dwarfdump --debug-info - | FileCheck %s
+// RUN: dsymutil --linker llvm -f -oso-prepend-path=%t.dir \
+// RUN:   -verify \
+// RUN:   -y %p/dummy-debug-map.map -o - \
+// RUN:     | llvm-dwarfdump --debug-info - | FileCheck %s
 
 #include "Empty.h"
 int main() {

diff  --git a/llvm/test/tools/dsymutil/X86/multiple-inputs.test b/llvm/test/tools/dsymutil/X86/multiple-inputs.test
index ea541426eb17e1..6e1ed2e48c6d70 100644
--- a/llvm/test/tools/dsymutil/X86/multiple-inputs.test
+++ b/llvm/test/tools/dsymutil/X86/multiple-inputs.test
@@ -28,4 +28,3 @@ RUN: llvm-dwarfdump -a %t.dSYM/Contents/Resources/DWARF/basic-lto-dw4.macho.x86_
 RUN: not dsymutil -f -oso-prepend-path=%p/.. %t/basic.macho.x86_64 %t/basic-archive.macho.x86_64 %t/basic-lto.macho.x86_64 %t/basic-lto-dw4.macho.x86_64 -o %t.dSYM 2>&1 | FileCheck %s
 
 CHECK: error: cannot use -o with multiple inputs in flat mode
-

diff  --git a/llvm/test/tools/dsymutil/X86/object-prefix-path.test b/llvm/test/tools/dsymutil/X86/object-prefix-path.test
index 16956e0f94521e..9ac5ad755ec132 100644
--- a/llvm/test/tools/dsymutil/X86/object-prefix-path.test
+++ b/llvm/test/tools/dsymutil/X86/object-prefix-path.test
@@ -7,5 +7,10 @@ RUN:   %p/dummy-debug-map.map -o %t \
 RUN:   -object-prefix-map=/ModuleCache=/ModuleCacheRenamed \
 RUN:   2>&1 | FileCheck %s
 
+RUN: dsymutil --linker llvm -verify -f -oso-prepend-path=%t.dir -y \
+RUN:   %p/dummy-debug-map.map -o %t \
+RUN:   -object-prefix-map=/ModuleCache=/ModuleCacheRenamed \
+RUN:   2>&1 | FileCheck %s
+
 CHECK:     warning: {{.*}}Bar.pcm:
 CHECK-NOT: warning: {{.*}}Foo.pcm:

diff  --git a/llvm/test/tools/dsymutil/X86/op-convert-offset.test b/llvm/test/tools/dsymutil/X86/op-convert-offset.test
index 80cfc867b1d92f..fa780993bd0d6d 100644
--- a/llvm/test/tools/dsymutil/X86/op-convert-offset.test
+++ b/llvm/test/tools/dsymutil/X86/op-convert-offset.test
@@ -24,6 +24,14 @@ RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/op-convert
 RUN: llvm-dwarfdump %p/../Inputs/private/tmp/op-convert-offset/op-convert-offset.o 2>&1 | FileCheck %s --check-prefix OBJ
 RUN: llvm-dwarfdump %t.dSYM 2>&1 | FileCheck %s --check-prefix DSYM
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs \
+RUN:  %p/../Inputs/private/tmp/op-convert-offset/op-convert-offset \
+RUN:  -o %t.dSYM 2>&1
+RUN: llvm-dwarfdump \
+RUN:   %p/../Inputs/private/tmp/op-convert-offset/op-convert-offset.o 2>&1 \
+RUN:   | FileCheck %s --check-prefix OBJ
+RUN: llvm-dwarfdump %t.dSYM 2>&1 | FileCheck %s --check-prefix DSYM
+
 OBJ: 0x0000007d:   DW_TAG_base_type
 OBJ:                 DW_AT_name      ("DW_ATE_unsigned_1")
 OBJ:                 DW_AT_encoding  (DW_ATE_unsigned)
@@ -42,4 +50,4 @@ DSYM:                 DW_AT_byte_size (0x01)
 DSYM: 0x0000009b:     DW_TAG_formal_parameter
 DSYM:                   DW_AT_location        (DW_OP_breg2 RCX+0, DW_OP_constu 0xff, DW_OP_and, DW_OP_convert (0x00000084) "DW_ATE_unsigned_1", DW_OP_convert (0x00000088) "DW_ATE_unsigned_8", DW_OP_stack_value)
 DSYM:                   DW_AT_name    ("b")
-DSYM:                   DW_AT_type    (0x000000b6 "_Bool")
+DSYM:                   DW_AT_type    ({{.*}} "_Bool")

diff  --git a/llvm/test/tools/dsymutil/X86/op-convert.test b/llvm/test/tools/dsymutil/X86/op-convert.test
index a03869865599db..15725a0435d488 100644
--- a/llvm/test/tools/dsymutil/X86/op-convert.test
+++ b/llvm/test/tools/dsymutil/X86/op-convert.test
@@ -1,6 +1,9 @@
 # RUN: dsymutil -f -o %t --verify -oso-prepend-path=%p/../Inputs -y %s
 # RUN: llvm-dwarfdump %t | FileCheck %s
 
+# RUN: dsymutil --linker llvm -f -o %t --verify -oso-prepend-path=%p/../Inputs -y %s
+# RUN: llvm-dwarfdump %t | FileCheck %s
+
 ---
 triple:          'x86_64-apple-darwin'
 objects:

diff  --git a/llvm/test/tools/dsymutil/X86/papertrail-warnings.test b/llvm/test/tools/dsymutil/X86/papertrail-warnings.test
index 1678adb8ae7b7a..69c851a335ad69 100644
--- a/llvm/test/tools/dsymutil/X86/papertrail-warnings.test
+++ b/llvm/test/tools/dsymutil/X86/papertrail-warnings.test
@@ -1,5 +1,7 @@
 RUN: env RC_DEBUG_OPTIONS=1 dsymutil -f %p/../Inputs/basic.macho.x86_64 -o - | llvm-dwarfdump -v - | FileCheck -DMSG=%errc_ENOENT %s
 
+RUN: env RC_DEBUG_OPTIONS=1 dsymutil --linker llvm -f %p/../Inputs/basic.macho.x86_64 -o - | llvm-dwarfdump -v - | FileCheck -DMSG=%errc_ENOENT %s
+
 CHECK: .debug_info contents:
 CHECK:  Compile Unit:
 CHECK:  DW_TAG_compile_unit [1] *

diff  --git a/llvm/test/tools/dsymutil/X86/reflection-dump.test b/llvm/test/tools/dsymutil/X86/reflection-dump.test
index bcee07d5929eb6..77694773ab0f97 100644
--- a/llvm/test/tools/dsymutil/X86/reflection-dump.test
+++ b/llvm/test/tools/dsymutil/X86/reflection-dump.test
@@ -9,6 +9,9 @@ RUN: yaml2obj %p/../Inputs/reflection_metadata.yaml -o %t.dir/tmp/reflection_met
 RUN: dsymutil -oso-prepend-path=%t.dir %t.dir/main -o %t.dir/main.dSYM
 RUN: llvm-objdump -s %t.dir/main.dSYM/Contents/Resources/DWARF/main | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%t.dir %t.dir/main -o %t.dir/main.dSYM
+RUN: llvm-objdump -s %t.dir/main.dSYM/Contents/Resources/DWARF/main | FileCheck %s
+
 REQUIRES: host-byteorder-little-endian
 
 

diff  --git a/llvm/test/tools/dsymutil/X86/remarks-linking-archive.text b/llvm/test/tools/dsymutil/X86/remarks-linking-archive.text
index 117349c78396d9..5578fd28b89a8a 100644
--- a/llvm/test/tools/dsymutil/X86/remarks-linking-archive.text
+++ b/llvm/test/tools/dsymutil/X86/remarks-linking-archive.text
@@ -7,10 +7,17 @@ RUN: dsymutil -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs
 Check that the remark file in the bundle exists and is sane:
 RUN: llvm-bcanalyzer -dump %t/basic.macho.remarks.archive.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.archive.x86_64 | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs %t/basic.macho.remarks.archive.x86_64
+
+Check that the remark file in the bundle exists and is sane:
+RUN: llvm-bcanalyzer -dump %t/basic.macho.remarks.archive.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.archive.x86_64 | FileCheck %s
+
 Check that we don't error if we're missing remark files from an archive, but we warn instead.
 Instead of creating a new binary, just remove the remarks prepend path.
 RUN: dsymutil -oso-prepend-path=%p/../Inputs %t/basic.macho.remarks.archive.x86_64 2>&1 | FileCheck %s --check-prefix=CHECK-MISSING
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../Inputs %t/basic.macho.remarks.archive.x86_64 2>&1 | FileCheck %s --check-prefix=CHECK-MISSING
+
 CHECK: <Meta
 CHECK: <Remark Num
 CHECK: <Remark Num

diff  --git a/llvm/test/tools/dsymutil/X86/remarks-linking-bundle-empty.test b/llvm/test/tools/dsymutil/X86/remarks-linking-bundle-empty.test
index 12418694f144ee..ad8accf24530d1 100644
--- a/llvm/test/tools/dsymutil/X86/remarks-linking-bundle-empty.test
+++ b/llvm/test/tools/dsymutil/X86/remarks-linking-bundle-empty.test
@@ -6,3 +6,8 @@ RUN: dsymutil -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs
 
 Check that the remark file in the bundle does not exist:
 RUN: not cat %t/basic.macho.remarks.empty.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.empty.x86_64 2>&1
+
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs %t/basic.macho.remarks.empty.x86_64
+
+Check that the remark file in the bundle does not exist:
+RUN: not cat %t/basic.macho.remarks.empty.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.empty.x86_64 2>&1

diff  --git a/llvm/test/tools/dsymutil/X86/remarks-linking-bundle.test b/llvm/test/tools/dsymutil/X86/remarks-linking-bundle.test
index 11b9a6f9d5eab7..3fb7fd59d44bc1 100644
--- a/llvm/test/tools/dsymutil/X86/remarks-linking-bundle.test
+++ b/llvm/test/tools/dsymutil/X86/remarks-linking-bundle.test
@@ -7,10 +7,18 @@ RUN: dsymutil -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs
 Check that the remark file in the bundle exists and is sane:
 RUN: llvm-bcanalyzer -dump %t/basic.macho.remarks.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.x86_64 | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs %t/basic.macho.remarks.x86_64
+
+Check that the remark file in the bundle exists and is sane:
+RUN: llvm-bcanalyzer -dump %t/basic.macho.remarks.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.x86_64 | FileCheck %s
+
 Now emit it in a 
diff erent format: YAML.
 RUN: dsymutil -remarks-output-format=yaml -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs %t/basic.macho.remarks.x86_64
 RUN: cat %t/basic.macho.remarks.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.x86_64 | FileCheck %s --check-prefix=CHECK-YAML
 
+RUN: dsymutil --linker llvm -remarks-output-format=yaml -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs %t/basic.macho.remarks.x86_64
+RUN: cat %t/basic.macho.remarks.x86_64.dSYM/Contents/Resources/Remarks/basic.macho.remarks.x86_64 | FileCheck %s --check-prefix=CHECK-YAML
+
 CHECK: <Meta
 CHECK: <Remark Num
 CHECK: <Remark Num

diff  --git a/llvm/test/tools/dsymutil/X86/remarks-linking-fat-bundle.test b/llvm/test/tools/dsymutil/X86/remarks-linking-fat-bundle.test
index c0b4beffee4fee..632da020607146 100644
--- a/llvm/test/tools/dsymutil/X86/remarks-linking-fat-bundle.test
+++ b/llvm/test/tools/dsymutil/X86/remarks-linking-fat-bundle.test
@@ -11,6 +11,13 @@ RUN: llvm-bcanalyzer -dump %t/fat.macho.remarks.x86.dSYM/Contents/Resources/Rema
 RUN: llvm-bcanalyzer -dump %t/fat.macho.remarks.x86.dSYM/Contents/Resources/Remarks/fat.macho.remarks.x86-x86_64 | FileCheck %s
 RUN: llvm-bcanalyzer -dump %t/fat.macho.remarks.x86.dSYM/Contents/Resources/Remarks/fat.macho.remarks.x86-i386 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-i386
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p/../Inputs -remarks-prepend-path=%p/../Inputs %t/fat.macho.remarks.x86
+
+Check that the remark files in the bundle exist and are all sane:
+RUN: llvm-bcanalyzer -dump %t/fat.macho.remarks.x86.dSYM/Contents/Resources/Remarks/fat.macho.remarks.x86-x86_64h | FileCheck %s
+RUN: llvm-bcanalyzer -dump %t/fat.macho.remarks.x86.dSYM/Contents/Resources/Remarks/fat.macho.remarks.x86-x86_64 | FileCheck %s
+RUN: llvm-bcanalyzer -dump %t/fat.macho.remarks.x86.dSYM/Contents/Resources/Remarks/fat.macho.remarks.x86-i386 | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-i386
+
 CHECK: <Meta
 CHECK: <Remark Num
 CHECK: <Remark Num

diff  --git a/llvm/test/tools/dsymutil/X86/reproducer.test b/llvm/test/tools/dsymutil/X86/reproducer.test
index 7e65d4ee2d77b2..128cd5388011c2 100644
--- a/llvm/test/tools/dsymutil/X86/reproducer.test
+++ b/llvm/test/tools/dsymutil/X86/reproducer.test
@@ -28,12 +28,18 @@ RUN: llvm-dwarfdump -a %t.generate | FileCheck %s
 RUN: rm -rf %t
 RUN: not dsymutil -f -o %t.error -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 2>&1 | FileCheck %s --check-prefix=ERROR
 
+RUN: not dsymutil --linker llvm -f -o %t.error -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 2>&1 | FileCheck %s --check-prefix=ERROR
+
 # Use the reproducer.
 RUN: dsymutil -use-reproducer %t.repro -f -o - -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
 
+RUN: dsymutil --linker llvm -use-reproducer %t.repro -f -o - -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
+
 # Using a reproducer takes precedence.
 RUN: dsymutil -gen-reproducer -use-reproducer %t.repro -f -o - -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
 
+RUN: dsymutil --linker llvm -gen-reproducer -use-reproducer %t.repro -f -o - -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 | llvm-dwarfdump -a - | FileCheck %s
+
 CHECK: .debug_info
 CHECK:  DW_TAG_compile_unit
 CHECK-NEXT:    DW_AT_producer ("Apple LLVM version 6.0 (clang-600.0.39) (based on LLVM 3.5svn)")

diff  --git a/llvm/test/tools/dsymutil/X86/statistics.test b/llvm/test/tools/dsymutil/X86/statistics.test
index 0237aede280011..082d20b1c53714 100644
--- a/llvm/test/tools/dsymutil/X86/statistics.test
+++ b/llvm/test/tools/dsymutil/X86/statistics.test
@@ -1,4 +1,5 @@
 # RUN: dsymutil -statistics -oso-prepend-path=%p/.. %p/../Inputs/basic.macho.x86_64 %p/../Inputs/basic-archive.macho.x86_64 %p/../Inputs/basic-lto.macho.x86_64 %p/../Inputs/basic-lto-dw4.macho.x86_64 -o %t 2>&1 | FileCheck %s
+# RUN: dsymutil --linker llvm -statistics -oso-prepend-path=%p/.. %p/../Inputs/basic.macho.x86_64 %p/../Inputs/basic-archive.macho.x86_64 %p/../Inputs/basic-lto.macho.x86_64 %p/../Inputs/basic-lto-dw4.macho.x86_64 -o %t 2>&1 | FileCheck %s
 #
 # CHECK: -------------------------------------------------------------------------------
 # CHECK-NEXT: Filename                                           Object         dSYM   Change

diff  --git a/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test b/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
index a16330d8c1b054..9d959e06fb958f 100644
--- a/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
+++ b/llvm/test/tools/dsymutil/X86/swift-ast-x86_64.test
@@ -3,6 +3,12 @@ RUN: dsymutil -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -o %T/
 RUN: llvm-readobj --sections --section-data %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=READOBJ
 RUN: llvm-dwarfdump --show-section-sizes %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=DWARFDUMP
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -o %T/swift-ast.dSYM -verbose -no-swiftmodule-timestamp | FileCheck %s --check-prefix=DSYMUTIL
+RUN: dsymutil --linker llvm -oso-prepend-path %p/.. %p/../Inputs/swift-ast.macho.x86_64 -o %T/swift-ast.dSYM -verbose | FileCheck %s --check-prefix=DSYMUTIL
+RUN: llvm-readobj --sections --section-data %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=READOBJ
+RUN: llvm-dwarfdump --show-section-sizes %T/swift-ast.dSYM/Contents/Resources/DWARF/swift-ast.macho.x86_64 | FileCheck %s --check-prefix=DWARFDUMP
+
+
 The tested object file has been created by the dummy Swift code:
 let x = 1
 

diff  --git a/llvm/test/tools/dsymutil/X86/swift-dwarf-loc.test b/llvm/test/tools/dsymutil/X86/swift-dwarf-loc.test
index 65282223a30338..d12e2e137d7e49 100644
--- a/llvm/test/tools/dsymutil/X86/swift-dwarf-loc.test
+++ b/llvm/test/tools/dsymutil/X86/swift-dwarf-loc.test
@@ -1,5 +1,7 @@
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/swift-dwarf-loc.macho.x86_64 -no-output -verbose | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/swift-dwarf-loc.macho.x86_64 -no-output -verbose | FileCheck %s
+
 This test checks that dsymutil generates a valid dwarf location for a symbol with no flags set.
 
 The following IR was compiled for x86_64-apple:

diff  --git a/llvm/test/tools/dsymutil/X86/tail-call-linking.test b/llvm/test/tools/dsymutil/X86/tail-call-linking.test
index 29ae2cc544cf62..f4e2afe808a09d 100644
--- a/llvm/test/tools/dsymutil/X86/tail-call-linking.test
+++ b/llvm/test/tools/dsymutil/X86/tail-call-linking.test
@@ -1,4 +1,7 @@
 RUN: dsymutil -oso-prepend-path=%p %p/Inputs/tail-call.macho.x86_64 -o %t.dSYM
 RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_pc
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%p %p/Inputs/tail-call.macho.x86_64 -o %t.dSYM
+RUN: llvm-dwarfdump %t.dSYM | FileCheck %s -implicit-check-not=DW_AT_call_pc
+
 CHECK: DW_AT_call_pc  (0x0000000100000f95)

diff  --git a/llvm/test/tools/dsymutil/X86/thinlto.test b/llvm/test/tools/dsymutil/X86/thinlto.test
index ebd4068a5c1275..2d2195805f3aab 100644
--- a/llvm/test/tools/dsymutil/X86/thinlto.test
+++ b/llvm/test/tools/dsymutil/X86/thinlto.test
@@ -20,5 +20,8 @@ $ xcrun clang++ -g -flto=thin -O2 foo.cpp bar.cpp -c
 $ xcrun clang++ -flto=thin foo.o bar.o -Xlinker -object_path_lto -Xlinker lto -shared -o foobar.dylib
 
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/thinlto/foobar.dylib -o %t.dSYM 2>&1 | FileCheck %s --allow-empty
+
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/thinlto/foobar.dylib -o %t.dSYM 2>&1 | FileCheck %s --allow-empty
+
 CHECK-NOT: could not find object file symbol for symbol __ZZ9function2vE12magic_static
 CHECK-NOT: could not find object file symbol for symbol __ZGVZ9function2vE12magic_static

diff  --git a/llvm/test/tools/dsymutil/X86/timestamp-mismatch.test b/llvm/test/tools/dsymutil/X86/timestamp-mismatch.test
index 7d41905e79514d..f41fe31f5549b7 100644
--- a/llvm/test/tools/dsymutil/X86/timestamp-mismatch.test
+++ b/llvm/test/tools/dsymutil/X86/timestamp-mismatch.test
@@ -5,6 +5,8 @@ RUN: cp %p/../Inputs/basic2.macho.x86_64.o %t/Inputs
 RUN: cp %p/../Inputs/basic3.macho.x86_64.o %t/Inputs
 RUN: dsymutil -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 -o %t.dSYM 2>&1 | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path=%t %t/Inputs/basic.macho.x86_64 -o %t.dSYM 2>&1 | FileCheck %s
+
 CHECK: warning: {{.*}}/Inputs/basic1.macho.x86_64.o: timestamp mismatch between object file ({{.*}}) and debug map ({{.*}})
 CHECK: warning: {{.*}}/Inputs/basic2.macho.x86_64.o: timestamp mismatch between object file ({{.*}}) and debug map ({{.*}})
 CHECK: warning: {{.*}}/Inputs/basic3.macho.x86_64.o: timestamp mismatch between object file ({{.*}}) and debug map ({{.*}})

diff  --git a/llvm/test/tools/dsymutil/X86/tls-variable.test b/llvm/test/tools/dsymutil/X86/tls-variable.test
index 19f9e380f22be7..48027e4f98714d 100644
--- a/llvm/test/tools/dsymutil/X86/tls-variable.test
+++ b/llvm/test/tools/dsymutil/X86/tls-variable.test
@@ -10,6 +10,7 @@
 # RUN: echo '      - { sym: __Z3foov, objAddr: 0x0, binAddr: 0x10000, size: 0x10 }' >> %t2.map
 # RUN: echo '...' >> %t2.map
 # RUN: dsymutil -y %t2.map --keep-function-for-static -f -o - | llvm-dwarfdump -a - | FileCheck %s
+# RUN: dsymutil --linker llvm -y %t2.map --keep-function-for-static -f -o - | llvm-dwarfdump -a - | FileCheck %s
 
 # CHECK: file format Mach-O 64-bit x86-64
 # CHECK: .debug_info contents:

diff  --git a/llvm/test/tools/dsymutil/X86/union-fwd-decl.test b/llvm/test/tools/dsymutil/X86/union-fwd-decl.test
index c73db0e3f5532e..c5c8c9e93e0a06 100644
--- a/llvm/test/tools/dsymutil/X86/union-fwd-decl.test
+++ b/llvm/test/tools/dsymutil/X86/union-fwd-decl.test
@@ -48,6 +48,9 @@ Note that the link order in the last command matters for this test.
 RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/union/a.out -o %t.dSYM
 RUN: llvm-dwarfdump %t.dSYM | FileCheck %s
 
+RUN: dsymutil --linker llvm -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/union/a.out -o %t.dSYM
+RUN: llvm-dwarfdump %t.dSYM | FileCheck %s
+
 CHECK: DW_TAG_compile_unit
 
 CHECK:          DW_AT_name      ("Container_ivars")

diff  --git a/llvm/test/tools/dsymutil/X86/verify.test b/llvm/test/tools/dsymutil/X86/verify.test
index 2a7b1938e843f7..b48af48473b635 100644
--- a/llvm/test/tools/dsymutil/X86/verify.test
+++ b/llvm/test/tools/dsymutil/X86/verify.test
@@ -25,6 +25,25 @@
 # QUIET-SUCCESS-NOT: input verification failed
 # QUIET-SUCCESS-NOT: output verification failed
 # BOGUS: error: invalid verify type specified: 'bogus'
+#
+# Positive tests in regular and verbose mode.
+# RUN: dsymutil --linker llvm -verify -oso-prepend-path=%p/.. %p/../Inputs/basic.macho.x86_64 %p/../Inputs/basic-archive.macho.x86_64 %p/../Inputs/basic-lto.macho.x86_64 %p/../Inputs/basic-lto-dw4.macho.x86_64 -o %t 2>&1 | FileCheck %s --allow-empty --check-prefix=QUIET-SUCCESS
+# RUN: dsymutil --linker llvm -verify -verbose -oso-prepend-path=%p/.. %p/../Inputs/basic.macho.x86_64 %p/../Inputs/basic-archive.macho.x86_64 %p/../Inputs/basic-lto.macho.x86_64 %p/../Inputs/basic-lto-dw4.macho.x86_64 -o %t 2>&1 | FileCheck %s --check-prefixes=QUIET-SUCCESS,VERBOSE
+#
+# # Negative output tests in regular and verbose mode.
+# (Invalid object generated from ../Inputs/invalid.s by modified the low PC.)
+# RUN: not dsymutil --linker llvm -verify -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefix=QUIET-OUTPUT-FAIL
+# RUN: not dsymutil --linker llvm -verify-dwarf=output -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefix=QUIET-OUTPUT-FAIL
+# RUN: not dsymutil --linker llvm -verify -verbose -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefixes=QUIET-OUTPUT-FAIL,VERBOSE
+#
+# # Negative input & output tests in regular and verbose mode. Only output failures result in a non-zero exit code.
+# RUN: dsymutil --linker llvm -verify-dwarf=input -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefix=QUIET-INPUT-FAIL
+# RUN: dsymutil --linker llvm -verify-dwarf=input -verbose -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefix=QUIET-INPUT-FAIL
+# RUN: dsymutil --linker llvm -verify-dwarf=none -verbose -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefixes=QUIET-SUCCESS
+# RUN: not dsymutil --linker llvm -verify-dwarf=bogus -verbose -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefixes=BOGUS
+# RUN: not dsymutil --linker llvm -verify-dwarf=all -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefixes=QUIET-OUTPUT-FAIL,QUIET-INPUT-FAIL
+# RUN: not dsymutil --linker llvm -verify-dwarf=all -verbose -oso-prepend-path=%p/../Inputs -y %s -o %t 2>&1 | FileCheck %s --check-prefixes=VERBOSE-INPUT-FAIL
+
 
 ---
 triple:          'x86_64-apple-darwin'

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/DWARFLinkerParallel/gc-default.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/DWARFLinkerParallel/gc-default.test
deleted file mode 100644
index 5083fd54c136e3..00000000000000
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/DWARFLinkerParallel/gc-default.test
+++ /dev/null
@@ -1,134 +0,0 @@
-## This test checks that debug info related to deleted code (marked with
-## default tombstone value) is removed.
-
-# RUN: yaml2obj %s -o %t.o
-# RUN: llvm-dwarfutil --linker llvm %t.o %t1.out 2>&1 | FileCheck %s --allow-empty
-
-#CHECK: LLVM parallel dwarflinker is not implemented yet.
-
---- !ELF
-FileHeader:
-  Class:    ELFCLASS64
-  Data:     ELFDATA2LSB
-  Type:     ET_REL
-  Machine:  EM_X86_64
-Sections:
-  - Name:            .text
-    Type:            SHT_PROGBITS
-    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
-    Address:         0x1000
-    Size:            0x1b
-DWARF:
-  debug_abbrev:
-    - Table:
-      - Tag:      DW_TAG_compile_unit
-        Children: DW_CHILDREN_yes
-        Attributes:
-          - Attribute: DW_AT_producer
-            Form:      DW_FORM_string
-          - Attribute: DW_AT_language
-            Form:      DW_FORM_data2
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-          - Attribute: DW_AT_low_pc
-            Form:      DW_FORM_addr
-          - Attribute: DW_AT_high_pc
-            Form:      DW_FORM_data8
-      - Tag:      DW_TAG_subprogram
-        Children: DW_CHILDREN_no
-        Attributes:
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-          - Attribute: DW_AT_low_pc
-            Form:      DW_FORM_addr
-          - Attribute: DW_AT_high_pc
-            Form:      DW_FORM_data8
-          - Attribute: DW_AT_type
-            Form:      DW_FORM_ref4
-      - Tag:      DW_TAG_class_type
-        Children: DW_CHILDREN_yes
-        Attributes:
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-      - Tag:      DW_TAG_member
-        Children: DW_CHILDREN_no
-        Attributes:
-          - Attribute: DW_AT_type
-            Form:      DW_FORM_ref4
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-      - Tag:      DW_TAG_class_type
-        Children: DW_CHILDREN_no
-        Attributes:
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-          - Attribute: DW_AT_declaration
-            Form:      DW_FORM_flag_present
-      - Tag:      DW_TAG_class_type
-        Children: DW_CHILDREN_yes
-        Attributes:
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-          - Attribute: DW_AT_declaration
-            Form:      DW_FORM_flag_present
-      - Tag:      DW_TAG_template_type_parameter
-        Children: DW_CHILDREN_no
-        Attributes:
-          - Attribute: DW_AT_type
-            Form:      DW_FORM_ref4
-      - Tag:      DW_TAG_base_type
-        Children: DW_CHILDREN_no
-        Attributes:
-          - Attribute: DW_AT_name
-            Form:      DW_FORM_string
-  debug_info:
-    - Version: 4
-      Entries:
-        - AbbrCode: 1
-          Values:
-            - CStr: by_hand
-            - Value:  0x04
-            - CStr: CU1
-            - Value:  0x1000
-            - Value:  0x1b
-        - AbbrCode: 3
-          Values:
-            - CStr: class1
-        - AbbrCode: 4
-          Values:
-            - Value:  0x0000006c
-            - CStr: member1
-        - AbbrCode: 0
-        - AbbrCode: 3
-          Values:
-            - CStr: class2
-        - AbbrCode: 4
-          Values:
-            - Value:  0x0000006c
-            - CStr: member1
-        - AbbrCode: 0
-        - AbbrCode: 3
-          Values:
-            - CStr: class3
-        - AbbrCode: 4
-          Values:
-            - Value:  0x0000006c
-            - CStr: member1
-        - AbbrCode: 0
-        - AbbrCode: 8
-          Values:
-            - CStr: int
-        - AbbrCode: 2
-          Values:
-            - CStr: foo1
-            - Value:  0x1000
-            - Value:  0x10
-            - Value:  0x0000002a
-        - AbbrCode: 2
-          Values:
-            - CStr: foo2
-            - Value:  0x0
-            - Value:  0x100
-            - Value:  0x00000040
-        - AbbrCode: 0
-...

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro-short.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro-short.test
index f500ad1d1232d1..95def093e66a2f 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro-short.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro-short.test
@@ -7,6 +7,10 @@
 # RUN: llvm-dwarfdump --verify %t1 | FileCheck --check-prefix=VERIFY %s
 # RUN: llvm-dwarfdump -a %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1
+# RUN: llvm-dwarfdump --verify %t1 | FileCheck --check-prefix=VERIFY %s
+# RUN: llvm-dwarfdump -a %t1 | FileCheck %s
+
 # VERIFY: No errors.
 
 ##  Content:        "03000201064400020744000400":

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro.test
index a84653c612cb73..6797af9d578cf4 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf4-macro.test
@@ -39,16 +39,28 @@
 #RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 #RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACINFO
 
+#RUN: llvm-dwarfutil --linker llvm --garbage-collection %p/Inputs/dwarf4-macro.out %t1
+#RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACINFO
+
 ## Check that macro table preserved during simple copying.
 #
 #RUN: llvm-dwarfutil --no-garbage-collection %p/Inputs/dwarf4-macro.out %t1
 #RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 #RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACINFO
 
+#RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %p/Inputs/dwarf4-macro.out %t1
+#RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACINFO
+
 ## Check that macro table preserved during updating accelerator tables.
 #RUN: llvm-dwarfutil --no-garbage-collection --build-accelerator=DWARF %p/Inputs/dwarf4-macro.out %t1
 #RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
-#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefixes=MACINFO,NAMES
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefixes=MACINFO
+
+#RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %p/Inputs/dwarf4-macro.out %t1
+#RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefixes=MACINFO
 
 #CHECK: No errors.
 
@@ -2228,6 +2240,3 @@
 #MACINFO-NEXT: DW_MACINFO_define - lineno: 0 macro: __STDC_UTF_32__ 1
 #MACINFO-NEXT: DW_MACINFO_define - lineno: 0 macro: __GCC_HAVE_DWARF2_CFI_ASM 1
 
-
-#NAMES: .debug_names contents
-#NAMES: Name Index

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-addresses.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-addresses.test
index 50dd070633bc78..90c40fd1e4ab62 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-addresses.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-addresses.test
@@ -12,15 +12,27 @@
 # RUN: llvm-dwarfutil %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix DWARF-CHECK
-#
+
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix DWARF-CHECK
+
 # RUN: llvm-dwarfutil --no-garbage-collection %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
-#
+
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 # RUN: llvm-dwarfutil --no-garbage-collection --build-accelerator=DWARF %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 #CHECK: No errors.
 
 #DWARF-CHECK: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-attributes.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-attributes.test
index 779e165ab72b85..bf880c643a4dcd 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-attributes.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-attributes.test
@@ -6,15 +6,27 @@
 # RUN: llvm-dwarfutil %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
-#
+
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
+
 # RUN: llvm-dwarfutil --no-garbage-collection %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
-#
+
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
+
 # RUN: llvm-dwarfutil --no-garbage-collection --build-accelerator=DWARF %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
+
 #VERIFY-CHECK: No errors.
 
 #CHECK: .debug_abbrev

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-line-str.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-line-str.test
index 8f2957350484ea..52bf01c3a7130b 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-line-str.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-line-str.test
@@ -6,15 +6,27 @@
 # RUN: llvm-dwarfutil %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
-#
+
 # RUN: llvm-dwarfutil --no-garbage-collection %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
-#
+
 # RUN: llvm-dwarfutil --no-garbage-collection --build-accelerator=DWARF %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
+
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
+
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s --check-prefix VERIFY-CHECK
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s
+
 #VERIFY-CHECK: No errors.
 
 #CHECK: .debug_info

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-loclists.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-loclists.test
index b02c76e3367ec1..719944b3d224e5 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-loclists.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-loclists.test
@@ -16,6 +16,18 @@
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix DWARF-CHECK
+
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 #CHECK: No errors.
 
 #DWARF-CHECK: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-opcodeop.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-opcodeop.test
index c19462c309e06f..c9e89b2d1d1258 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-opcodeop.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-opcodeop.test
@@ -6,6 +6,10 @@
 # RUN: llvm-dwarfdump --verify %t1 | FileCheck --check-prefix=VERIFY %s
 # RUN: llvm-dwarfdump -a %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1 2>&1 | FileCheck --check-prefix=ERR %s
+# RUN: llvm-dwarfdump --verify %t1 | FileCheck --check-prefix=VERIFY %s
+# RUN: llvm-dwarfdump -a %t1 | FileCheck %s
+
 # ERR: error: opcode_operands_table is not supported
 
 # VERIFY: No errors.

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-short.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-short.test
index ecafd814baf3ce..b38aae6f816d9e 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-short.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro-short.test
@@ -8,6 +8,10 @@
 # RUN: llvm-dwarfdump --verify %t1 | FileCheck --check-prefix=VERIFY %s
 # RUN: llvm-dwarfdump -a %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1 2>&1 | FileCheck --check-prefix=WARN %s
+# RUN: llvm-dwarfdump --verify %t1 | FileCheck --check-prefix=VERIFY %s
+# RUN: llvm-dwarfdump -a %t1 | FileCheck %s
+
 # WARN: warning: DW_MACRO_define_strx unsupported yet. Convert to DW_MACRO_define_strp.
 # WARN: warning: DW_MACRO_undef_strx unsupported yet. Convert to DW_MACRO_undef_strp.
 # WARN: warning: DW_MACRO_import and DW_MACRO_import_sup are unsupported yet. remove.

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro.test
index 57487be9d42707..053d55871d4553 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-macro.test
@@ -39,16 +39,28 @@
 #RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 #RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACRO
 
+#RUN: llvm-dwarfutil --linker llvm --garbage-collection %p/Inputs/dwarf5-macro.out %t1
+#RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACRO
+
 ## Check that macro table preserved during simple copying.
 #
 #RUN: llvm-dwarfutil --no-garbage-collection %p/Inputs/dwarf5-macro.out %t1
 #RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 #RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACRO
 
+#RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %p/Inputs/dwarf5-macro.out %t1
+#RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefix=MACRO
+
 ## Check that macro table preserved during updating accelerator tables.
 #RUN: llvm-dwarfutil --no-garbage-collection --build-accelerator=DWARF %p/Inputs/dwarf5-macro.out %t1
 #RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
-#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefixes=MACRO,NAMES
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefixes=MACRO
+
+#RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %p/Inputs/dwarf5-macro.out %t1
+#RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+#RUN: llvm-dwarfdump -a  %t1 | FileCheck %s --check-prefixes=MACRO
 
 #CHECK: No errors.
 
@@ -2233,6 +2245,3 @@
 #MACRO-NEXT: DW_MACRO_define_str{{[px]}} - lineno: 0 macro: __STDC_UTF_16__ 1
 #MACRO-NEXT: DW_MACRO_define_str{{[px]}} - lineno: 0 macro: __STDC_UTF_32__ 1
 #MACRO-NEXT: DW_MACRO_define_str{{[px]}} - lineno: 0 macro: __GCC_HAVE_DWARF2_CFI_ASM 1
-
-#NAMES: .debug_names contents
-#NAMES: Name Index

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-rnglists.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-rnglists.test
index d9458e901944fa..78b53897346c48 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-rnglists.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/dwarf5-rnglists.test
@@ -8,14 +8,26 @@
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix DWARF-CHECK
 
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix DWARF-CHECK
+
 # RUN: llvm-dwarfutil --no-garbage-collection %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 # RUN: llvm-dwarfutil --no-garbage-collection --build-accelerator=DWARF %t.o %t1
 # RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
 # RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
 
+# RUN: llvm-dwarfutil --linker llvm --no-garbage-collection --build-accelerator=DWARF %t.o %t1
+# RUN: llvm-dwarfdump -verify %t1 | FileCheck %s
+# RUN: llvm-dwarfdump -a --verbose %t1 | FileCheck %s --check-prefix UPD-DWARF-CHECK
+
 #CHECK: No errors.
 
 #DWARF-CHECK: DW_TAG_compile_unit

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-default.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-default.test
index b364a751a7c7cd..90cb99858c9efc 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-default.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-default.test
@@ -7,14 +7,20 @@
 
 # RUN: llvm-dwarfutil --linker apple %t.o - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-GC
 
+# RUN: llvm-dwarfutil --linker llvm %t.o - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-GC
+
 # RUN: llvm-dwarfutil --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-GC
 
 # RUN: llvm-dwarfutil --no-garbage-collection --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-GC
 
 # RUN: llvm-dwarfutil --garbage-collection --no-garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-NOGC
 
+# RUN: llvm-dwarfutil --linker llvm --garbage-collection --no-garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-NOGC
+
 # RUN: llvm-dwarfutil %t.o --tombstone=universal - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-GC
 
+# RUN: llvm-dwarfutil --linker llvm %t.o --tombstone=universal - | llvm-dwarfdump -a - | FileCheck %s --check-prefixes=CHECK,CHECK-GC
+
 # CHECK: DW_TAG_compile_unit
 # CHECK: DW_AT_name{{.*}}"CU1"
 # CHECK: DW_TAG_class_type

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-func-overlapping-address-ranges.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-func-overlapping-address-ranges.test
index cfbb7cb105586e..232f6a5553e571 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-func-overlapping-address-ranges.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-func-overlapping-address-ranges.test
@@ -5,6 +5,9 @@
 # RUN: llvm-dwarfutil --garbage-collection %t.o %t1
 # RUN: llvm-dwarfdump -a %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm --garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -a %t1 | FileCheck %s
+
 # CHECK: DW_TAG_compile_unit
 # CHECK: DW_AT_name{{.*}}"CU1"
 # CHECK: DW_AT_low_pc{{.*}}0000000000001000

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-maxpc.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-maxpc.test
index 6184f724961296..cb3b435ea9aa4c 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-maxpc.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-maxpc.test
@@ -6,6 +6,9 @@
 # RUN: llvm-dwarfutil --tombstone=maxpc --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s
 # RUN: llvm-dwarfutil --tombstone=universal --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm --tombstone=maxpc --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s
+# RUN: llvm-dwarfutil --linker llvm --tombstone=universal --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s
+
 # CHECK: DW_TAG_compile_unit
 # CHECK: DW_AT_name{{.*}}"CU1"
 # CHECK: DW_TAG_class_type

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-no-garbage.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-no-garbage.test
index 11252295617d7a..1f5ddd78adaa24 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-no-garbage.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-no-garbage.test
@@ -4,6 +4,8 @@
 # RUN: yaml2obj %s -o %t.o
 # RUN: llvm-dwarfutil --tombstone=maxpc --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm --tombstone=maxpc --garbage-collection %t.o - | llvm-dwarfdump -a - | FileCheck %s
+
 # CHECK: DW_TAG_compile_unit
 # CHECK: DW_AT_name{{.*}}"CU1"
 # CHECK: DW_TAG_class_type

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-unit-overlapping-address-ranges.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-unit-overlapping-address-ranges.test
index f9d42c28d42098..2ee1d73b6f92f0 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-unit-overlapping-address-ranges.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/gc-unit-overlapping-address-ranges.test
@@ -6,6 +6,9 @@
 # RUN: llvm-dwarfutil --garbage-collection %t.o %t1
 # RUN: llvm-dwarfdump -a %t1 | FileCheck %s
 
+# RUN: llvm-dwarfutil --linker llvm --garbage-collection %t.o %t1
+# RUN: llvm-dwarfdump -a %t1 | FileCheck %s
+
 # CHECK: DW_TAG_compile_unit
 # CHECK: DW_AT_name{{.*}}"CU1"
 # CHECK: DW_TAG_class_type

diff  --git a/llvm/test/tools/llvm-dwarfutil/ELF/X86/verify.test b/llvm/test/tools/llvm-dwarfutil/ELF/X86/verify.test
index 844e8fb671af3e..e9557edddde427 100644
--- a/llvm/test/tools/llvm-dwarfutil/ELF/X86/verify.test
+++ b/llvm/test/tools/llvm-dwarfutil/ELF/X86/verify.test
@@ -7,18 +7,23 @@
 
 ## Verify resulting debug info after --garbage-collection optimisation.
 # RUN: llvm-dwarfutil %t.o %t1 --verify
+# RUN: llvm-dwarfutil --linker llvm %t.o %t1 --verify
 
 ## Verify separate debug file after --garbage-collection optimisation.
 # RUN: llvm-dwarfutil %t.o --separate-debug-file %t1 --verify
+# RUN: llvm-dwarfutil --linker llvm %t.o --separate-debug-file %t1 --verify
 
 ## Verify not optimised resulting debug info.
 # RUN: not llvm-dwarfutil --no-garbage-collection %t.o %t1 --verify 2>&1 | FileCheck %s -DFILE=%t1
+# RUN: not llvm-dwarfutil --linker llvm --no-garbage-collection %t.o %t1 --verify 2>&1 | FileCheck %s -DFILE=%t1
 
 ## Verify not optimised resulting separate debug file.
 # RUN: not llvm-dwarfutil --no-garbage-collection %t.o --separate-debug-file %t1 --verify 2>&1 | FileCheck %s -DFILE=%t1.debug
+# RUN: not llvm-dwarfutil --linker llvm --no-garbage-collection %t.o --separate-debug-file %t1 --verify 2>&1 | FileCheck %s -DFILE=%t1.debug
 
 ## Check that verification is disabled when destination is stdout.
 # RUN: llvm-dwarfutil %t.o - --verify 2>&1 | FileCheck %s --check-prefix=CHECK-STDOUT
+# RUN: llvm-dwarfutil --linker llvm %t.o - --verify 2>&1 | FileCheck %s --check-prefix=CHECK-STDOUT
 
 # CHECK: error: '[[FILE]]': output verification failed
 # CHECK-STDOUT: warning: verification skipped because writing to stdout

diff  --git a/llvm/tools/dsymutil/BinaryHolder.cpp b/llvm/tools/dsymutil/BinaryHolder.cpp
index d8293f7f354f2d..c6661f4058f102 100644
--- a/llvm/tools/dsymutil/BinaryHolder.cpp
+++ b/llvm/tools/dsymutil/BinaryHolder.cpp
@@ -238,6 +238,7 @@ BinaryHolder::getObjectEntry(StringRef Filename, TimestampTy Timestamp) {
   if (isArchive(Filename)) {
     StringRef ArchiveFilename = getArchiveAndObjectName(Filename).first;
     std::lock_guard<std::mutex> Lock(ArchiveCacheMutex);
+    ArchiveRefCounter[ArchiveFilename]++;
     if (ArchiveCache.count(ArchiveFilename)) {
       return ArchiveCache[ArchiveFilename]->getObjectEntry(Filename, Timestamp,
                                                            Verbose);
@@ -258,6 +259,7 @@ BinaryHolder::getObjectEntry(StringRef Filename, TimestampTy Timestamp) {
   // If this is an object, we might have it cached. If not we'll have to load
   // it from the file system and cache it now.
   std::lock_guard<std::mutex> Lock(ObjectCacheMutex);
+  ObjectRefCounter[Filename]++;
   if (!ObjectCache.count(Filename)) {
     auto OE = std::make_unique<ObjectEntry>();
     auto Err = OE->load(VFS, Filename, Timestamp, Verbose);
@@ -276,5 +278,24 @@ void BinaryHolder::clear() {
   ObjectCache.clear();
 }
 
+void BinaryHolder::eraseObjectEntry(StringRef Filename) {
+  if (Verbose)
+    WithColor::note() << "erasing '" << Filename << "' from cache\n";
+
+  if (isArchive(Filename)) {
+    StringRef ArchiveFilename = getArchiveAndObjectName(Filename).first;
+    std::lock_guard<std::mutex> Lock(ArchiveCacheMutex);
+    ArchiveRefCounter[ArchiveFilename]--;
+    if (ArchiveRefCounter[ArchiveFilename] == 0)
+      ArchiveCache.erase(ArchiveFilename);
+    return;
+  }
+
+  std::lock_guard<std::mutex> Lock(ObjectCacheMutex);
+  ObjectRefCounter[Filename]--;
+  if (ObjectRefCounter[Filename] == 0)
+    ObjectCache.erase(Filename);
+}
+
 } // namespace dsymutil
 } // namespace llvm

diff  --git a/llvm/tools/dsymutil/BinaryHolder.h b/llvm/tools/dsymutil/BinaryHolder.h
index 84084c568cbea3..b70bf338936fa4 100644
--- a/llvm/tools/dsymutil/BinaryHolder.h
+++ b/llvm/tools/dsymutil/BinaryHolder.h
@@ -126,15 +126,18 @@ class BinaryHolder {
   getObjectEntry(StringRef Filename, TimestampTy Timestamp = TimestampTy());
 
   void clear();
+  void eraseObjectEntry(StringRef Filename);
 
 private:
   /// Cache of static archives. Objects that are part of a static archive are
   /// stored under this object, rather than in the map below.
   StringMap<std::unique_ptr<ArchiveEntry>> ArchiveCache;
+  DenseMap<StringRef, uint32_t> ArchiveRefCounter;
   std::mutex ArchiveCacheMutex;
 
   /// Object entries for objects that are not in a static archive.
   StringMap<std::unique_ptr<ObjectEntry>> ObjectCache;
+  DenseMap<StringRef, uint32_t> ObjectRefCounter;
   std::mutex ObjectCacheMutex;
 
   /// Virtual File System instance.

diff  --git a/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp b/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
index 4b281d5f19801a..5e94901c0babc4 100644
--- a/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
+++ b/llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
@@ -123,16 +123,22 @@ static void dumpDIE(const DWARFDie *DIE, bool Verbose) {
 /// specific \p DIE related to the warning.
 void DwarfLinkerForBinary::reportWarning(Twine Warning, Twine Context,
                                          const DWARFDie *DIE) const {
-  std::lock_guard<std::mutex> Guard(ErrorHandlerMutex);
-  warn(Warning, Context);
-  dumpDIE(DIE, Options.Verbose);
+  // FIXME: implement warning logging which does not block other threads.
+  if (ErrorHandlerMutex.try_lock()) {
+    warn(Warning, Context);
+    dumpDIE(DIE, Options.Verbose);
+    ErrorHandlerMutex.unlock();
+  }
 }
 
 void DwarfLinkerForBinary::reportError(Twine Error, Twine Context,
                                        const DWARFDie *DIE) const {
-  std::lock_guard<std::mutex> Guard(ErrorHandlerMutex);
-  error(Error, Context);
-  dumpDIE(DIE, Options.Verbose);
+  // FIXME: implement error logging which does not block other threads.
+  if (ErrorHandlerMutex.try_lock()) {
+    error(Error, Context);
+    dumpDIE(DIE, Options.Verbose);
+    ErrorHandlerMutex.unlock();
+  }
 }
 
 ErrorOr<const object::ObjectFile &>
@@ -233,9 +239,23 @@ DwarfLinkerForBinary::loadObject(const DebugMapObject &Obj,
 
   if (ErrorOrObj) {
     Res = std::make_unique<OutDWARFFile>(
-        Obj.getObjectFilename(), DWARFContext::create(*ErrorOrObj),
+        Obj.getObjectFilename(),
+        DWARFContext::create(
+            *ErrorOrObj, DWARFContext::ProcessDebugRelocations::Process,
+            nullptr, "",
+            [&](Error Err) {
+              handleAllErrors(std::move(Err), [&](ErrorInfoBase &Info) {
+                reportError(Info.message());
+              });
+            },
+            [&](Error Warning) {
+              handleAllErrors(std::move(Warning), [&](ErrorInfoBase &Info) {
+                reportWarning(Info.message());
+              });
+            }),
         std::make_unique<AddressesMap>(*this, *ErrorOrObj, Obj),
-        Obj.empty() ? Obj.getWarnings() : EmptyWarnings);
+        Obj.empty() ? Obj.getWarnings() : EmptyWarnings,
+        [&](StringRef FileName) { BinHolder.eraseObjectEntry(FileName); });
 
     Error E = RL.link(*ErrorOrObj);
     if (Error NewE = handleErrors(
@@ -1036,8 +1056,10 @@ std::optional<int64_t> DwarfLinkerForBinary::AddressManager<AddressesMapBase>::
   default: {
     assert(false && "Specified operation does not have address operand");
   } break;
+  case dwarf::DW_OP_const2u:
   case dwarf::DW_OP_const4u:
   case dwarf::DW_OP_const8u:
+  case dwarf::DW_OP_const2s:
   case dwarf::DW_OP_const4s:
   case dwarf::DW_OP_const8s:
   case dwarf::DW_OP_addr: {

diff  --git a/llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp b/llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp
index 47a23e8448cc49..fbbead16a03709 100644
--- a/llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp
+++ b/llvm/tools/llvm-dwarfutil/DebugInfoLinker.cpp
@@ -98,15 +98,18 @@ class ObjFileAddressMap : public AddressMapBase {
     return std::nullopt;
   }
 
-  std::optional<int64_t> getExprOpAddressRelocAdjustment(
-      DWARFUnit &U, const DWARFExpression::Operation &Op, uint64_t StartOffset,
-      uint64_t EndOffset) override {
+  std::optional<int64_t>
+  getExprOpAddressRelocAdjustment(DWARFUnit &U,
+                                  const DWARFExpression::Operation &Op,
+                                  uint64_t, uint64_t) override {
     switch (Op.getCode()) {
     default: {
       assert(false && "Specified operation does not have address operand");
     } break;
+    case dwarf::DW_OP_const2u:
     case dwarf::DW_OP_const4u:
     case dwarf::DW_OP_const8u:
+    case dwarf::DW_OP_const2s:
     case dwarf::DW_OP_const4s:
     case dwarf::DW_OP_const8s:
     case dwarf::DW_OP_addr: {
@@ -287,23 +290,33 @@ static std::string getMessageForDeletedAcceleratorTables(
 template <typename Linker, typename OutDwarfFile, typename AddressMapBase>
 Error linkDebugInfoImpl(object::ObjectFile &File, const Options &Options,
                         raw_pwrite_stream &OutStream) {
+  std::mutex ErrorHandlerMutex;
+
   auto ReportWarn = [&](const Twine &Message, StringRef Context,
                         const DWARFDie *Die) {
-    warning(Message, Context);
-
-    if (!Options.Verbose || !Die)
+    // FIXME: implement warning logging which does not block other threads.
+    if (!ErrorHandlerMutex.try_lock())
       return;
 
-    DIDumpOptions DumpOpts;
-    DumpOpts.ChildRecurseDepth = 0;
-    DumpOpts.Verbose = Options.Verbose;
+    warning(Message, Context);
+    if (Options.Verbose && Die) {
+      DIDumpOptions DumpOpts;
+      DumpOpts.ChildRecurseDepth = 0;
+      DumpOpts.Verbose = Options.Verbose;
 
-    WithColor::note() << "    in DIE:\n";
-    Die->dump(errs(), /*Indent=*/6, DumpOpts);
+      WithColor::note() << "    in DIE:\n";
+      Die->dump(errs(), /*Indent=*/6, DumpOpts);
+    }
+    ErrorHandlerMutex.unlock();
   };
   auto ReportErr = [&](const Twine &Message, StringRef Context,
                        const DWARFDie *) {
+    // FIXME: implement error logging which does not block other threads.
+    if (!ErrorHandlerMutex.try_lock())
+      return;
+
     WithColor::error(errs(), Context) << Message << '\n';
+    ErrorHandlerMutex.unlock();
   };
 
   // Create DWARF linker.
@@ -325,7 +338,18 @@ Error linkDebugInfoImpl(object::ObjectFile &File, const Options &Options,
   std::vector<std::string> EmptyWarnings;
 
   // Add object files to the DWARFLinker.
-  std::unique_ptr<DWARFContext> Context = DWARFContext::create(File);
+  std::unique_ptr<DWARFContext> Context = DWARFContext::create(
+      File, DWARFContext::ProcessDebugRelocations::Process, nullptr, "",
+      [&](Error Err) {
+        handleAllErrors(std::move(Err), [&](ErrorInfoBase &Info) {
+          ReportErr(Info.message(), "", nullptr);
+        });
+      },
+      [&](Error Warning) {
+        handleAllErrors(std::move(Warning), [&](ErrorInfoBase &Info) {
+          ReportWarn(Info.message(), "", nullptr);
+        });
+      });
   std::unique_ptr<ObjFileAddressMap<AddressMapBase>> AddressesMap(
       std::make_unique<ObjFileAddressMap<AddressMapBase>>(*Context, Options,
                                                           File));

diff  --git a/llvm/unittests/CodeGen/DwarfStringPoolEntryRefTest.cpp b/llvm/unittests/CodeGen/DwarfStringPoolEntryRefTest.cpp
index 6e901f7a18f27d..25db003ea81deb 100644
--- a/llvm/unittests/CodeGen/DwarfStringPoolEntryRefTest.cpp
+++ b/llvm/unittests/CodeGen/DwarfStringPoolEntryRefTest.cpp
@@ -61,40 +61,25 @@ bool isEntryEqual(const DwarfStringPoolEntry &LHS,
 }
 
 TEST(DwarfStringPoolEntryRefTest, TestShortEntry) {
-  BumpPtrAllocator Allocator;
-  DwarfStringPoolEntry DwarfEntry1 = {nullptr, 0, 0};
-  StringMapEntry<DwarfStringPoolEntry *> *StringEntry1 =
-      StringMapEntry<DwarfStringPoolEntry *>::create("Key1", Allocator,
-                                                     &DwarfEntry1);
-
-  EXPECT_TRUE(StringEntry1->getKey() == "Key1");
-  EXPECT_TRUE(StringEntry1->second->Symbol == nullptr);
-  EXPECT_TRUE(StringEntry1->second->Offset == 0);
-  EXPECT_TRUE(StringEntry1->second->Index == 0);
+  DwarfStringPoolEntryWithExtString DwarfEntry1 = {{nullptr, 0, 0}, "Key1"};
 
-  DwarfStringPoolEntryRef Ref1(*StringEntry1);
+  DwarfStringPoolEntryRef Ref1(DwarfEntry1);
   EXPECT_TRUE(Ref1.getString() == "Key1");
   EXPECT_TRUE(Ref1.getOffset() == 0);
   EXPECT_TRUE(Ref1.getIndex() == 0);
   EXPECT_TRUE(isEntryEqual(Ref1.getEntry(), DwarfEntry1));
 
-  DwarfStringPoolEntryRef Ref2(*StringEntry1);
+  DwarfStringPoolEntryRef Ref2(DwarfEntry1);
   EXPECT_TRUE(Ref2.getString() == "Key1");
   EXPECT_TRUE(Ref2.getOffset() == 0);
   EXPECT_TRUE(isEntryEqual(Ref2.getEntry(), DwarfEntry1));
   EXPECT_TRUE(Ref1 == Ref2);
   EXPECT_FALSE(Ref1 != Ref2);
 
-  DwarfStringPoolEntry DwarfEntry2 = {nullptr, 0x1000, 1};
-  StringMapEntry<DwarfStringPoolEntry *> *StringEntry2 =
-      StringMapEntry<DwarfStringPoolEntry *>::create("Key2", Allocator,
-                                                     &DwarfEntry2);
-  EXPECT_TRUE(StringEntry2->getKey() == "Key2");
-  EXPECT_TRUE(StringEntry2->second->Symbol == nullptr);
-  EXPECT_TRUE(StringEntry2->second->Offset == 0x1000);
-  EXPECT_TRUE(StringEntry2->second->Index == 1);
+  DwarfStringPoolEntryWithExtString DwarfEntry2 = {{nullptr, 0x1000, 1},
+                                                   "Key2"};
 
-  DwarfStringPoolEntryRef Ref3(*StringEntry2);
+  DwarfStringPoolEntryRef Ref3(DwarfEntry2);
   EXPECT_TRUE(Ref3.getString() == "Key2");
   EXPECT_TRUE(Ref3.getOffset() == 0x1000);
   EXPECT_TRUE(Ref3.getIndex() == 1);
@@ -105,11 +90,8 @@ TEST(DwarfStringPoolEntryRefTest, TestShortEntry) {
 TEST(DwarfStringPoolEntryRefTest, CompareFullAndShort) {
   BumpPtrAllocator Allocator;
 
-  DwarfStringPoolEntry DwarfEntry1 = {nullptr, 0, 0};
-  StringMapEntry<DwarfStringPoolEntry *> *StringEntry1 =
-      StringMapEntry<DwarfStringPoolEntry *>::create("Key1", Allocator,
-                                                     &DwarfEntry1);
-  DwarfStringPoolEntryRef Ref1(*StringEntry1);
+  DwarfStringPoolEntryWithExtString DwarfEntry1 = {{nullptr, 0, 0}, "Key1"};
+  DwarfStringPoolEntryRef Ref1(DwarfEntry1);
 
   StringMapEntry<DwarfStringPoolEntry> *StringEntry2 =
       StringMapEntry<DwarfStringPoolEntry>::create(

diff  --git a/llvm/unittests/DWARFLinkerParallel/CMakeLists.txt b/llvm/unittests/DWARFLinkerParallel/CMakeLists.txt
index e06806103b313c..5eeec23df4edba 100644
--- a/llvm/unittests/DWARFLinkerParallel/CMakeLists.txt
+++ b/llvm/unittests/DWARFLinkerParallel/CMakeLists.txt
@@ -6,7 +6,6 @@ set(LLVM_LINK_COMPONENTS
 add_llvm_unittest(DWARFLinkerParallelTests
   DWARFLinkerTest.cpp
   StringPoolTest.cpp
-  StringTableTest.cpp
   )
 
 target_link_libraries(DWARFLinkerParallelTests PRIVATE LLVMTestingSupport)

diff  --git a/llvm/unittests/DWARFLinkerParallel/StringPoolTest.cpp b/llvm/unittests/DWARFLinkerParallel/StringPoolTest.cpp
index 11ae18c9e8621f..84199f696a59de 100644
--- a/llvm/unittests/DWARFLinkerParallel/StringPoolTest.cpp
+++ b/llvm/unittests/DWARFLinkerParallel/StringPoolTest.cpp
@@ -28,20 +28,17 @@ TEST(StringPoolTest, TestStringPool) {
     std::pair<StringEntry *, bool> Entry = Strings.insert("test");
     EXPECT_TRUE(Entry.second);
     EXPECT_TRUE(Entry.first->getKey() == "test");
-    EXPECT_TRUE(Entry.first->second == nullptr);
 
     StringEntry *EntryPtr = Entry.first;
 
     Entry = Strings.insert("test");
     EXPECT_FALSE(Entry.second);
     EXPECT_TRUE(Entry.first->getKey() == "test");
-    EXPECT_TRUE(Entry.first->second == nullptr);
     EXPECT_TRUE(EntryPtr == Entry.first);
 
     Entry = Strings.insert("test2");
     EXPECT_TRUE(Entry.second);
     EXPECT_TRUE(Entry.first->getKey() == "test2");
-    EXPECT_TRUE(Entry.first->second == nullptr);
     EXPECT_TRUE(EntryPtr != Entry.first);
   });
 }
@@ -54,7 +51,6 @@ TEST(StringPoolTest, TestStringPoolParallel) {
     std::pair<StringEntry *, bool> Entry = Strings.insert(std::to_string(Idx));
     EXPECT_TRUE(Entry.second);
     EXPECT_TRUE(Entry.first->getKey() == std::to_string(Idx));
-    EXPECT_TRUE(Entry.first->second == nullptr);
   });
 
   // Check data.
@@ -62,7 +58,6 @@ TEST(StringPoolTest, TestStringPoolParallel) {
     std::pair<StringEntry *, bool> Entry = Strings.insert(std::to_string(Idx));
     EXPECT_FALSE(Entry.second);
     EXPECT_TRUE(Entry.first->getKey() == std::to_string(Idx));
-    EXPECT_TRUE(Entry.first->second == nullptr);
   });
 }
 

diff  --git a/llvm/unittests/DWARFLinkerParallel/StringTableTest.cpp b/llvm/unittests/DWARFLinkerParallel/StringTableTest.cpp
deleted file mode 100644
index 02bb95001acd42..00000000000000
--- a/llvm/unittests/DWARFLinkerParallel/StringTableTest.cpp
+++ /dev/null
@@ -1,118 +0,0 @@
-//===- llvm/unittest/DWARFLinkerParallel/StringTableTest.cpp --------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/DWARFLinkerParallel/StringTable.h"
-#include "llvm/Support/Parallel.h"
-#include "gtest/gtest.h"
-#include <cstdlib>
-
-using namespace llvm;
-using namespace dwarflinker_parallel;
-
-namespace {
-
-TEST(StringPoolTest, TestStringTable) {
-  struct StringDescription {
-    const char *Str = nullptr;
-    uint64_t Idx = 0;
-    uint64_t Offset = 0;
-  };
-
-  SmallVector<StringDescription> InputStrings = {
-      {"first", 0, 0}, {"second", 1, 6}, {"third", 2, 13}};
-
-  StringPool Strings;
-  StringTable OutStrings(Strings, nullptr);
-
-  // StringPool uses PerThreadBumpPtrAllocator which should be accessed from
-  // threads created by ThreadPoolExecutor. Use TaskGroup to run on
-  // ThreadPoolExecutor threads.
-  parallel::TaskGroup tg;
-
-  tg.spawn([&]() {
-    // Check string insertion.
-    StringEntry *FirstPtr = Strings.insert(InputStrings[0].Str).first;
-    StringEntry *SecondPtr = Strings.insert(InputStrings[1].Str).first;
-    StringEntry *ThirdPtr = Strings.insert(InputStrings[2].Str).first;
-
-    FirstPtr = OutStrings.add(FirstPtr);
-    SecondPtr = OutStrings.add(SecondPtr);
-    ThirdPtr = OutStrings.add(ThirdPtr);
-
-    // Check fields of inserted strings.
-    EXPECT_TRUE(FirstPtr->getKey() == InputStrings[0].Str);
-    EXPECT_TRUE(FirstPtr->getValue()->Offset == InputStrings[0].Offset);
-    EXPECT_TRUE(FirstPtr->getValue()->Index == InputStrings[0].Idx);
-
-    EXPECT_TRUE(SecondPtr->getKey() == InputStrings[1].Str);
-    EXPECT_TRUE(SecondPtr->getValue()->Offset == InputStrings[1].Offset);
-    EXPECT_TRUE(SecondPtr->getValue()->Index == InputStrings[1].Idx);
-
-    EXPECT_TRUE(ThirdPtr->getKey() == InputStrings[2].Str);
-    EXPECT_TRUE(ThirdPtr->getValue()->Offset == InputStrings[2].Offset);
-    EXPECT_TRUE(ThirdPtr->getValue()->Index == InputStrings[2].Idx);
-
-    // Check order enumerated strings.
-    uint64_t CurIdx = 0;
-    std::function<void(DwarfStringPoolEntryRef)> checkStr =
-        [&](DwarfStringPoolEntryRef Entry) {
-          EXPECT_TRUE(Entry.getEntry().isIndexed());
-          EXPECT_TRUE(Entry.getIndex() == CurIdx);
-          EXPECT_TRUE(Entry.getOffset() == InputStrings[CurIdx].Offset);
-          EXPECT_TRUE(Entry.getString() == InputStrings[CurIdx].Str);
-
-          CurIdx++;
-        };
-
-    OutStrings.forEach(checkStr);
-  });
-}
-
-TEST(StringPoolTest, TestStringTableWithTranslator) {
-  std::string Word;
-  std::function<StringRef(StringRef)> TranslatorFunc =
-      [&](StringRef InputString) -> StringRef {
-    Word.clear();
-    for (auto Sym : InputString)
-      Word.insert(Word.begin(), Sym);
-    Word += '0';
-    return Word;
-  };
-
-  StringPool Strings;
-  StringTable OutStrings(Strings, TranslatorFunc);
-
-  // StringPool uses PerThreadBumpPtrAllocator which should be accessed from
-  // threads created by ThreadPoolExecutor. Use TaskGroup to run on
-  // ThreadPoolExecutor threads.
-  parallel::TaskGroup tg;
-
-  tg.spawn([&]() {
-    StringEntry *FirstPtr = Strings.insert("first").first;
-    StringEntry *SecondPtr = Strings.insert("second").first;
-    StringEntry *ThirdPtr = Strings.insert("third").first;
-
-    FirstPtr = OutStrings.add(FirstPtr);
-    SecondPtr = OutStrings.add(SecondPtr);
-    ThirdPtr = OutStrings.add(ThirdPtr);
-
-    EXPECT_TRUE(FirstPtr->getKey() == "tsrif0");
-    EXPECT_TRUE(FirstPtr->getValue()->Offset == 0);
-    EXPECT_TRUE(FirstPtr->getValue()->Index == 0);
-
-    EXPECT_TRUE(SecondPtr->getKey() == "dnoces0");
-    EXPECT_TRUE(SecondPtr->getValue()->Offset == 7);
-    EXPECT_TRUE(SecondPtr->getValue()->Index == 1);
-
-    EXPECT_TRUE(ThirdPtr->getKey() == "driht0");
-    EXPECT_TRUE(ThirdPtr->getValue()->Offset == 15);
-    EXPECT_TRUE(ThirdPtr->getValue()->Index == 2);
-  });
-}
-
-} // anonymous namespace


        


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