[lld] r255390 - [lld][MachO] Recognize __thread_bss sections as zero-fill and set all the

Lang Hames via llvm-commits llvm-commits at lists.llvm.org
Fri Dec 11 15:25:10 PST 2015 

Author: lhames
Date: Fri Dec 11 17:25:09 2015
New Revision: 255390

URL: http://llvm.org/viewvc/llvm-project?rev=255390&view=rev
Log:
[lld][MachO] Recognize __thread_bss sections as zero-fill and set all the
appropriate bits.

This fixes the remaining clang regression test failures when linking clang with
lld on Darwin.

Modified:
    lld/trunk/lib/ReaderWriter/MachO/Atoms.h
    lld/trunk/lib/ReaderWriter/MachO/File.h
    lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h
    lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
    lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
    lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
    lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileYAML.cpp
    lld/trunk/test/mach-o/run-tlv-pass-x86-64.yaml

Modified: lld/trunk/lib/ReaderWriter/MachO/Atoms.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/Atoms.h?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/Atoms.h (original)
+++ lld/trunk/lib/ReaderWriter/MachO/Atoms.h Fri Dec 11 17:25:09 2015
@@ -25,11 +25,11 @@ public:
 
   // Constructor for zero-fill content
   MachODefinedAtom(const File &f, const StringRef name, Scope scope,
-                   uint64_t size, bool noDeadStrip, Alignment align)
+                   ContentType type, uint64_t size, bool noDeadStrip,
+                   Alignment align)
       : SimpleDefinedAtom(f), _name(name),
         _content(ArrayRef<uint8_t>(nullptr, size)), _align(align),
-        _contentType(DefinedAtom::typeZeroFill),
-        _scope(scope), _merge(mergeNo), _thumb(false),
+        _contentType(type), _scope(scope), _merge(mergeNo), _thumb(false),
         _noDeadStrip(noDeadStrip) {}
 
   uint64_t size() const override { return _content.size(); }

Modified: lld/trunk/lib/ReaderWriter/MachO/File.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/File.h?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/File.h (original)
+++ lld/trunk/lib/ReaderWriter/MachO/File.h Fri Dec 11 17:25:09 2015
@@ -87,9 +87,22 @@ public:
     DefinedAtom::Alignment align(
         inSection->alignment,
         sectionOffset % inSection->alignment);
+
+    DefinedAtom::ContentType type = DefinedAtom::typeUnknown;
+    switch (inSection->type) {
+    case llvm::MachO::S_ZEROFILL:
+      type = DefinedAtom::typeZeroFill;
+      break;
+    case llvm::MachO::S_THREAD_LOCAL_ZEROFILL:
+      type = DefinedAtom::typeTLVInitialZeroFill;
+      break;
+    default:
+      llvm_unreachable("Unrecognized zero-fill section");
+    }
+
     auto *atom =
-       new (allocator()) MachODefinedAtom(*this, name, scope, size, noDeadStrip,
-                                          align);
+        new (allocator()) MachODefinedAtom(*this, name, scope, type, size,
+                                           noDeadStrip, align);
     addAtomForSection(inSection, atom, sectionOffset);
   }
 

Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h (original)
+++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFile.h Fri Dec 11 17:25:09 2015
@@ -142,6 +142,14 @@ struct Symbol {
   Hex64         value;
 };
 
+/// Check whether the given section type indicates a zero-filled section.
+// FIXME: Utility functions of this kind should probably be moved into
+//        llvm/Support.
+inline bool isZeroFillSection(SectionType T) {
+  return (T == llvm::MachO::S_ZEROFILL ||
+          T == llvm::MachO::S_THREAD_LOCAL_ZEROFILL);
+}
+
 /// A typedef so that YAML I/O can (de/en)code the protection bits of a segment.
 LLVM_YAML_STRONG_TYPEDEF(uint32_t, VMProtect)
 

Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp (original)
+++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileBinaryWriter.cpp Fri Dec 11 17:25:09 2015
@@ -289,12 +289,12 @@ MachOFileLayout::MachOFileLayout(const N
     unsigned relocCount = 0;
     uint64_t offset = _startOfSectionsContent;
     for (const Section &sect : file.sections) {
-      if (sect.type != llvm::MachO::S_ZEROFILL) {
+      if (isZeroFillSection(sect.type))
+        _sectInfo[&sect].fileOffset = 0;
+      else {
         offset = llvm::RoundUpToAlignment(offset, sect.alignment);
         _sectInfo[&sect].fileOffset = offset;
         offset += sect.content.size();
-      } else {
-        _sectInfo[&sect].fileOffset = 0;
       }
       relocCount += sect.relocations.size();
     }
@@ -530,7 +530,7 @@ void MachOFileLayout::buildFileOffsets()
     for (const Section *s : _segInfo[&sg].sections) {
       uint32_t sectOffset = s->address - sg.address;
       uint32_t sectFileSize =
-          s->type == llvm::MachO::S_ZEROFILL ? 0 : s->content.size();
+        isZeroFillSection(s->type) ? 0 : s->content.size();
       segFileSize = std::max(segFileSize, sectOffset + sectFileSize);
 
       _sectInfo[s].fileOffset = _segInfo[&sg].fileOffset + sectOffset;
@@ -655,7 +655,7 @@ std::error_code MachOFileLayout::writeSe
       setString16(section->segmentName, sect->segname);
       sect->addr      = section->address;
       sect->size      = section->content.size();
-      if (section->type == llvm::MachO::S_ZEROFILL)
+      if (isZeroFillSection(section->type))
         sect->offset  = 0;
       else
         sect->offset  = section->address - seg.address + segInfo.fileOffset;
@@ -883,7 +883,7 @@ std::error_code MachOFileLayout::writeLo
 void MachOFileLayout::writeSectionContent() {
   for (const Section &s : _file.sections) {
     // Copy all section content to output buffer.
-    if (s.type == llvm::MachO::S_ZEROFILL)
+    if (isZeroFillSection(s.type))
       continue;
     if (s.content.empty())
       continue;

Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp (original)
+++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileFromAtoms.cpp Fri Dec 11 17:25:09 2015
@@ -253,6 +253,8 @@ const MachOFinalSectionFromAtomType sect
                                                           typeTLVInitialData),
   ENTRY("__DATA", "__thread_ptrs",    S_THREAD_LOCAL_VARIABLE_POINTERS,
                                                           typeTLVInitializerPtr),
+  ENTRY("__DATA", "__thread_bss",     S_THREAD_LOCAL_ZEROFILL,
+                                                         typeTLVInitialZeroFill),
   ENTRY("__DATA", "__bss",            S_ZEROFILL,         typeZeroFill),
   ENTRY("__DATA", "__interposing",    S_INTERPOSING,      typeInterposingTuples),
 };
@@ -582,7 +584,7 @@ void Util::copySectionContent(Normalized
 
   for (SectionInfo *si : _sectionInfos) {
     Section *normSect = &file.sections[si->normalizedSectionIndex];
-    if (si->type == llvm::MachO::S_ZEROFILL) {
+    if (isZeroFillSection(si->type)) {
       const uint8_t *empty = nullptr;
       normSect->content = llvm::makeArrayRef(empty, si->size);
       continue;

Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp (original)
+++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp Fri Dec 11 17:25:09 2015
@@ -82,6 +82,8 @@ const MachORelocatableSectionToAtomType
   ENTRY("__DATA", "__thread_vars",    S_THREAD_LOCAL_VARIABLES,
                                                           typeThunkTLV),
   ENTRY("__DATA", "__thread_data", S_THREAD_LOCAL_REGULAR, typeTLVInitialData),
+  ENTRY("__DATA", "__thread_bss",     S_THREAD_LOCAL_ZEROFILL,
+                                                        typeTLVInitialZeroFill),
   ENTRY("",       "",                 S_INTERPOSING,      typeInterposingTuples),
   ENTRY("__LD",   "__compact_unwind", S_REGULAR,
                                                          typeCompactUnwindInfo),
@@ -232,7 +234,7 @@ void atomFromSymbol(DefinedAtom::Content
   uint64_t size = nextSymbolAddr - symbolAddr;
   uint64_t offset = symbolAddr - section.address;
   bool noDeadStrip = (symbolDescFlags & N_NO_DEAD_STRIP) || !scatterable;
-  if (section.type == llvm::MachO::S_ZEROFILL) {
+  if (isZeroFillSection(section.type)) {
     file.addZeroFillDefinedAtom(symbolName, symbolScope, offset, size,
                                 noDeadStrip, copyRefs, &section);
   } else {

Modified: lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileYAML.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileYAML.cpp?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileYAML.cpp (original)
+++ lld/trunk/lib/ReaderWriter/MachO/MachONormalizedFileYAML.cpp Fri Dec 11 17:25:09 2015
@@ -278,7 +278,7 @@ struct MappingTraits<Section> {
     io.mapOptional("attributes",      sect.attributes);
     io.mapOptional("alignment",       sect.alignment, (uint16_t)1);
     io.mapRequired("address",         sect.address);
-    if (sect.type == llvm::MachO::S_ZEROFILL) {
+    if (isZeroFillSection(sect.type)) {
       // S_ZEROFILL sections use "size:" instead of "content:"
       uint64_t size = sect.content.size();
       io.mapOptional("size",          size);

Modified: lld/trunk/test/mach-o/run-tlv-pass-x86-64.yaml
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/mach-o/run-tlv-pass-x86-64.yaml?rev=255390&r1=255389&r2=255390&view=diff
==============================================================================
--- lld/trunk/test/mach-o/run-tlv-pass-x86-64.yaml (original)
+++ lld/trunk/test/mach-o/run-tlv-pass-x86-64.yaml Fri Dec 11 17:25:09 2015
@@ -1,6 +1,7 @@
 # RUN: lld -flavor darwin -macosx_version_min 10.7 -arch x86_64 -print_atoms %s -o %t | FileCheck %s
 # RUN: not lld -flavor darwin -macosx_version_min 10.6 -arch x86_64 -o %t %s 2> %t2
 # RUN: FileCheck < %t2 %s --check-prefix=CHECK-ERROR
+# RUN: llvm-objdump -macho -private-headers %t | FileCheck %s --check-prefix=CHECK-LOADCMDS
 #
 # Test parsing of x86_64 tlv relocations.
 
@@ -30,12 +31,12 @@ sections:
         extern:          true
         symbol:          2
   - segment:         __DATA
-    section:         __thread_data
-    type:            S_THREAD_LOCAL_REGULAR
+    section:         __thread_bss
+    type:            S_THREAD_LOCAL_ZEROFILL
     attributes:      [  ]
     alignment:       4
     address:         0x0000000000000014
-    content:         [ 0x07, 0x00, 0x00, 0x00 ]
+    size:            4
   - segment:         __DATA
     section:         __thread_vars
     type:            S_THREAD_LOCAL_VARIABLES
@@ -111,8 +112,8 @@ page-size:       0x00000000
 # CHECK-NEXT:       - kind:            tlvInitSectionOffset
 # CHECK-NEXT:         offset:          16
 # CHECK-NEXT:         target:          '_x$tlv$init'
-# CHECK-NEXT:   - name:            '_x$tlv$init'
-# CHECK-NEXT:     type:            tlv-data
+# CHECK:       - name:            '_x$tlv$init'
+# CHECK-NEXT:    type:            tlv-zero-fill
 # CHECK:        - name:            _main
 # CHECK-NOT:    - name:
 # CHECK:          references:
@@ -131,3 +132,13 @@ page-size:       0x00000000
 # CHECK-NEXT:         target:          _x
 
 # CHECK-ERROR: targeted OS version does not support use of thread local variables in _main for architecture x86_64
+
+# CHECK-LOADCMDS: sectname __thread_bss
+# CHECK-LOADCMDS:   segname __DATA
+# CHECK-LOADCMDS:      addr 0x{{[0-9A-F]*}}
+# CHECK-LOADCMDS:      size 0x0000000000000004
+# CHECK-LOADCMDS:    offset 0
+# CHECK-LOADCMDS:     align 2^2 (4)
+# CHECK-LOADCMDS:    reloff 0
+# CHECK-LOADCMDS:    nreloc 0
+# CHECK-LOADCMDS:      type S_THREAD_LOCAL_ZEROFILL

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