[llvm] c9c687d - [NFC] Split portions of DWARFDataExtractor into new class (#140096)
via llvm-commits
llvm-commits at lists.llvm.org
Fri Jun 6 09:26:55 PDT 2025
Author: Sterling-Augustine
Date: 2025-06-06T09:26:51-07:00
New Revision: c9c687d8d039335118add0b9193b3927166dcc95
URL: https://github.com/llvm/llvm-project/commit/c9c687d8d039335118add0b9193b3927166dcc95
DIFF: https://github.com/llvm/llvm-project/commit/c9c687d8d039335118add0b9193b3927166dcc95.diff
LOG: [NFC] Split portions of DWARFDataExtractor into new class (#140096)
Currently, DWARFDataExtractor can extract data without performing
relocations, (eg, by checking if the section pointer is null) but is
coded such that it still depends on all the relocation machinery, like
DWARFSections and similar. All at build time.
Extract most functionality into a new class, DWARFDataExtractorBase, and
have DWARFDataExtractor add the relocation dependent pieces via CRTP.
Add a new class, DWARFDataExtractorSimple, which does no relocation at
all. This will allow moving DWARFDataExtractorSimple into a new lower-level,
lighter-weight library with fewer external build-time dependencies.
This is another in a series of refactoring changes to create a new
better-layered, low-level Dwarf library that can be called from
lower-level code without circular dependencies.
Added:
llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractorSimple.h
Modified:
llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h
llvm/lib/DebugInfo/DWARF/CMakeLists.txt
Removed:
llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
################################################################################
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h
index b86fe593cd52d..005ccd208cdda 100644
--- a/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractor.h
@@ -10,81 +10,59 @@
#define LLVM_DEBUGINFO_DWARF_DWARFDATAEXTRACTOR_H
#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/DebugInfo/DWARF/DWARFDataExtractorSimple.h"
+#include "llvm/DebugInfo/DWARF/DWARFObject.h"
+#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/Support/Compiler.h"
-#include "llvm/Support/DataExtractor.h"
namespace llvm {
-class DWARFObject;
-/// A DataExtractor (typically for an in-memory copy of an object-file section)
-/// plus a relocation map for that section, if there is one.
-class DWARFDataExtractor : public DataExtractor {
+/// A DWARFDataExtractor (typically for an in-memory copy of an object-file
+/// section) plus a relocation map for that section, if there is one.
+class DWARFDataExtractor : public DWARFDataExtractorBase<DWARFDataExtractor> {
const DWARFObject *Obj = nullptr;
const DWARFSection *Section = nullptr;
public:
+ using DWARFDataExtractorBase::DWARFDataExtractorBase;
+
/// Constructor for the normal case of extracting data from a DWARF section.
/// The DWARFSection's lifetime must be at least as long as the extractor's.
DWARFDataExtractor(const DWARFObject &Obj, const DWARFSection &Section,
bool IsLittleEndian, uint8_t AddressSize)
- : DataExtractor(Section.Data, IsLittleEndian, AddressSize), Obj(&Obj),
- Section(&Section) {}
-
- /// Constructor for cases when there are no relocations.
- DWARFDataExtractor(StringRef Data, bool IsLittleEndian, uint8_t AddressSize)
- : DataExtractor(Data, IsLittleEndian, AddressSize) {}
- DWARFDataExtractor(ArrayRef<uint8_t> Data, bool IsLittleEndian,
- uint8_t AddressSize)
- : DataExtractor(
- StringRef(reinterpret_cast<const char *>(Data.data()), Data.size()),
- IsLittleEndian, AddressSize) {}
+ : DWARFDataExtractorBase(Section.Data, IsLittleEndian, AddressSize),
+ Obj(&Obj), Section(&Section) {}
/// Truncating constructor
DWARFDataExtractor(const DWARFDataExtractor &Other, size_t Length)
- : DataExtractor(Other.getData().substr(0, Length), Other.isLittleEndian(),
- Other.getAddressSize()),
+ : DWARFDataExtractorBase(Other.getData().substr(0, Length),
+ Other.isLittleEndian(), Other.getAddressSize()),
Obj(Other.Obj), Section(Other.Section) {}
- /// Extracts the DWARF "initial length" field, which can either be a 32-bit
- /// value smaller than 0xfffffff0, or the value 0xffffffff followed by a
- /// 64-bit length. Returns the actual length, and the DWARF format which is
- /// encoded in the field. In case of errors, it returns {0, DWARF32} and
- /// leaves the offset unchanged.
- LLVM_ABI std::pair<uint64_t, dwarf::DwarfFormat>
- getInitialLength(uint64_t *Off, Error *Err = nullptr) const;
-
- std::pair<uint64_t, dwarf::DwarfFormat> getInitialLength(Cursor &C) const {
- return getInitialLength(&getOffset(C), &getError(C));
- }
-
/// Extracts a value and applies a relocation to the result if
/// one exists for the given offset.
- LLVM_ABI uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off,
- uint64_t *SectionIndex = nullptr,
- Error *Err = nullptr) const;
- uint64_t getRelocatedValue(Cursor &C, uint32_t Size,
- uint64_t *SectionIndex = nullptr) const {
- return getRelocatedValue(Size, &getOffset(C), SectionIndex, &getError(C));
- }
+ LLVM_ABI uint64_t getRelocatedValueImpl(uint32_t Size, uint64_t *Off,
+ uint64_t *SecNdx, Error *Err) const {
+ if (SecNdx)
+ *SecNdx = object::SectionedAddress::UndefSection;
+ if (!Section)
+ return getUnsigned(Off, Size, Err);
+ ErrorAsOutParameter ErrAsOut(Err);
+ std::optional<RelocAddrEntry> E = Obj->find(*Section, *Off);
+ uint64_t LocData = getUnsigned(Off, Size, Err);
+ if (!E || (Err && *Err))
+ return LocData;
+ if (SecNdx)
+ *SecNdx = E->SectionIndex;
- /// Extracts an address-sized value and applies a relocation to the result if
- /// one exists for the given offset.
- uint64_t getRelocatedAddress(uint64_t *Off, uint64_t *SecIx = nullptr) const {
- return getRelocatedValue(getAddressSize(), Off, SecIx);
+ uint64_t R = object::resolveRelocation(E->Resolver, E->Reloc,
+ E->SymbolValue, LocData);
+ if (E->Reloc2)
+ R = object::resolveRelocation(E->Resolver, *E->Reloc2, E->SymbolValue2,
+ R);
+ return R;
}
- uint64_t getRelocatedAddress(Cursor &C, uint64_t *SecIx = nullptr) const {
- return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx,
- &getError(C));
- }
-
- /// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding.
- /// There is a DWARF encoding that uses a PC-relative adjustment.
- /// For these values, \p AbsPosOffset is used to fix them, which should
- /// reflect the absolute address of this pointer.
- LLVM_ABI std::optional<uint64_t>
- getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
- uint64_t AbsPosOffset = 0) const;
};
} // end namespace llvm
diff --git a/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractorSimple.h b/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractorSimple.h
new file mode 100644
index 0000000000000..4c9a81093ca8f
--- /dev/null
+++ b/llvm/include/llvm/DebugInfo/DWARF/DWARFDataExtractorSimple.h
@@ -0,0 +1,198 @@
+//===- DWARFDataExtractorSimple.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_DEBUGINFO_DWARF_DWARFDATAEXTRACTORSIMPLE_H
+#define LLVM_DEBUGINFO_DWARF_DWARFDATAEXTRACTORSIMPLE_H
+
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/DataExtractor.h"
+#include "llvm/Support/Errc.h"
+#include "llvm/Support/MathExtras.h"
+
+namespace llvm {
+
+/// A DataExtractor suitable use for parsing dwarf from memory. Clients use
+/// Relocator::getRelocatedValueImpl to relocate values as appropriate.
+
+template <typename Relocator>
+class DWARFDataExtractorBase : public DataExtractor {
+
+public:
+ DWARFDataExtractorBase(StringRef Data, bool IsLittleEndian,
+ uint8_t AddressSize)
+ : DataExtractor(Data, IsLittleEndian, AddressSize) {}
+ DWARFDataExtractorBase(ArrayRef<uint8_t> Data, bool IsLittleEndian,
+ uint8_t AddressSize)
+ : DataExtractor(
+ StringRef(reinterpret_cast<const char *>(Data.data()), Data.size()),
+ IsLittleEndian, AddressSize) {}
+
+ /// Truncating constructor
+ DWARFDataExtractorBase(const DWARFDataExtractorBase &Other, size_t Length)
+ : DataExtractor(Other.getData().substr(0, Length), Other.isLittleEndian(),
+ Other.getAddressSize()) {}
+
+ /// Extracts a value and returns it as adjusted by the Relocator
+ LLVM_ABI uint64_t getRelocatedValue(uint32_t Size, uint64_t *Off,
+ uint64_t *SectionIndex = nullptr,
+ Error *Err = nullptr) const {
+ return static_cast<const Relocator *>(this)->getRelocatedValueImpl(
+ Size, Off, SectionIndex, Err);
+ }
+
+ LLVM_ABI uint64_t getRelocatedValue(Cursor &C, uint32_t Size,
+ uint64_t *SectionIndex = nullptr) const {
+ return getRelocatedValue(Size, &getOffset(C), SectionIndex, &getError(C));
+ }
+
+ /// Extracts an address-sized value.
+ LLVM_ABI uint64_t getRelocatedAddress(uint64_t *Off,
+ uint64_t *SecIx = nullptr) const {
+ return getRelocatedValue(getAddressSize(), Off, SecIx);
+ }
+
+ LLVM_ABI uint64_t getRelocatedAddress(Cursor &C,
+ uint64_t *SecIx = nullptr) const {
+ return getRelocatedValue(getAddressSize(), &getOffset(C), SecIx,
+ &getError(C));
+ }
+
+ /// Extracts the DWARF "initial length" field, which can either be a 32-bit
+ /// value smaller than 0xfffffff0, or the value 0xffffffff followed by a
+ /// 64-bit length. Returns the actual length, and the DWARF format which is
+ /// encoded in the field. In case of errors, it returns {0, DWARF32} and
+ /// leaves the offset unchanged.
+ LLVM_ABI std::pair<uint64_t, dwarf::DwarfFormat>
+ getInitialLength(uint64_t *Off, Error *Err = nullptr) const {
+ ErrorAsOutParameter ErrAsOut(Err);
+ if (Err && *Err)
+ return {0, dwarf::DWARF32};
+
+ Cursor C(*Off);
+ uint64_t Length = getRelocatedValue(C, 4);
+ dwarf::DwarfFormat Format = dwarf::DWARF32;
+ if (Length == dwarf::DW_LENGTH_DWARF64) {
+ Length = getRelocatedValue(C, 8);
+ Format = dwarf::DWARF64;
+ } else if (Length >= dwarf::DW_LENGTH_lo_reserved) {
+ cantFail(C.takeError());
+ if (Err)
+ *Err = createStringError(
+ std::errc::invalid_argument,
+ "unsupported reserved unit length of value 0x%8.8" PRIx64, Length);
+ return {0, dwarf::DWARF32};
+ }
+
+ if (C) {
+ *Off = C.tell();
+ return {Length, Format};
+ }
+ if (Err)
+ *Err = C.takeError();
+ else
+ consumeError(C.takeError());
+ return {0, dwarf::DWARF32};
+ }
+
+ LLVM_ABI std::pair<uint64_t, dwarf::DwarfFormat>
+ getInitialLength(Cursor &C) const {
+ return getInitialLength(&getOffset(C), &getError(C));
+ }
+
+ /// Extracts a DWARF-encoded pointer in \p Offset using \p Encoding.
+ /// There is a DWARF encoding that uses a PC-relative adjustment.
+ /// For these values, \p AbsPosOffset is used to fix them, which should
+ /// reflect the absolute address of this pointer.
+ LLVM_ABI std::optional<uint64_t>
+ getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
+ uint64_t PCRelOffset) const {
+ if (Encoding == dwarf::DW_EH_PE_omit)
+ return std::nullopt;
+
+ uint64_t Result = 0;
+ uint64_t OldOffset = *Offset;
+ // First get value
+ switch (Encoding & 0x0F) {
+ case dwarf::DW_EH_PE_absptr:
+ switch (getAddressSize()) {
+ case 2:
+ case 4:
+ case 8:
+ Result = getUnsigned(Offset, getAddressSize());
+ break;
+ default:
+ return std::nullopt;
+ }
+ break;
+ case dwarf::DW_EH_PE_uleb128:
+ Result = getULEB128(Offset);
+ break;
+ case dwarf::DW_EH_PE_sleb128:
+ Result = getSLEB128(Offset);
+ break;
+ case dwarf::DW_EH_PE_udata2:
+ Result = getUnsigned(Offset, 2);
+ break;
+ case dwarf::DW_EH_PE_udata4:
+ Result = getUnsigned(Offset, 4);
+ break;
+ case dwarf::DW_EH_PE_udata8:
+ Result = getUnsigned(Offset, 8);
+ break;
+ case dwarf::DW_EH_PE_sdata2:
+ Result = getSigned(Offset, 2);
+ break;
+ case dwarf::DW_EH_PE_sdata4:
+ Result = SignExtend64<32>(getRelocatedValue(4, Offset));
+ break;
+ case dwarf::DW_EH_PE_sdata8:
+ Result = getRelocatedValue(8, Offset);
+ break;
+ default:
+ return std::nullopt;
+ }
+ // Then add relative offset, if required
+ switch (Encoding & 0x70) {
+ case dwarf::DW_EH_PE_absptr:
+ // do nothing
+ break;
+ case dwarf::DW_EH_PE_pcrel:
+ Result += PCRelOffset;
+ break;
+ case dwarf::DW_EH_PE_datarel:
+ case dwarf::DW_EH_PE_textrel:
+ case dwarf::DW_EH_PE_funcrel:
+ case dwarf::DW_EH_PE_aligned:
+ default:
+ *Offset = OldOffset;
+ return std::nullopt;
+ }
+
+ return Result;
+ }
+};
+
+// Non relocating, low-level dwarf-data extractor. Suitable for use from
+// libraries that cannot have build-time dependencies on relocation providers.
+
+class DWARFDataExtractorSimple
+ : public DWARFDataExtractorBase<DWARFDataExtractorSimple> {
+ using DWARFDataExtractorBase::DWARFDataExtractorBase;
+
+ LLVM_ABI uint64_t getRelocatedValueImpl(uint32_t Size, uint64_t *Off,
+ uint64_t *SectionIndex = nullptr,
+ Error *Err = nullptr) const {
+ assert(SectionIndex == nullptr &&
+ "DWARFDATAExtractorSimple cannot take section indices.");
+ return getUnsigned(Off, Size, Err);
+ }
+};
+
+} // end namespace llvm
+#endif // LLVM_DEBUGINFO_DWARF_DWARFDATAEXTRACTOR_H
diff --git a/llvm/lib/DebugInfo/DWARF/CMakeLists.txt b/llvm/lib/DebugInfo/DWARF/CMakeLists.txt
index c4bacbdc484f5..cc9734f9f22be 100644
--- a/llvm/lib/DebugInfo/DWARF/CMakeLists.txt
+++ b/llvm/lib/DebugInfo/DWARF/CMakeLists.txt
@@ -5,7 +5,6 @@ add_llvm_component_library(LLVMDebugInfoDWARF
DWARFCFIProgram.cpp
DWARFCompileUnit.cpp
DWARFContext.cpp
- DWARFDataExtractor.cpp
DWARFDebugAbbrev.cpp
DWARFDebugAddr.cpp
DWARFDebugArangeSet.cpp
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
deleted file mode 100644
index 97434b3cfab82..0000000000000
--- a/llvm/lib/DebugInfo/DWARF/DWARFDataExtractor.cpp
+++ /dev/null
@@ -1,137 +0,0 @@
-//===- DWARFDataExtractor.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/DebugInfo/DWARF/DWARFDataExtractor.h"
-#include "llvm/DebugInfo/DWARF/DWARFObject.h"
-#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
-#include "llvm/Support/Errc.h"
-
-using namespace llvm;
-
-std::pair<uint64_t, dwarf::DwarfFormat>
-DWARFDataExtractor::getInitialLength(uint64_t *Off, Error *Err) const {
- ErrorAsOutParameter ErrAsOut(Err);
- if (Err && *Err)
- return {0, dwarf::DWARF32};
-
- Cursor C(*Off);
- uint64_t Length = getRelocatedValue(C, 4);
- dwarf::DwarfFormat Format = dwarf::DWARF32;
- if (Length == dwarf::DW_LENGTH_DWARF64) {
- Length = getRelocatedValue(C, 8);
- Format = dwarf::DWARF64;
- } else if (Length >= dwarf::DW_LENGTH_lo_reserved) {
- cantFail(C.takeError());
- if (Err)
- *Err = createStringError(
- errc::invalid_argument,
- "unsupported reserved unit length of value 0x%8.8" PRIx64, Length);
- return {0, dwarf::DWARF32};
- }
-
- if (C) {
- *Off = C.tell();
- return {Length, Format};
- }
- if (Err)
- *Err = C.takeError();
- else
- consumeError(C.takeError());
- return {0, dwarf::DWARF32};
-}
-
-uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint64_t *Off,
- uint64_t *SecNdx,
- Error *Err) const {
- if (SecNdx)
- *SecNdx = object::SectionedAddress::UndefSection;
- if (!Section)
- return getUnsigned(Off, Size, Err);
-
- ErrorAsOutParameter ErrAsOut(Err);
- std::optional<RelocAddrEntry> E = Obj->find(*Section, *Off);
- uint64_t LocData = getUnsigned(Off, Size, Err);
- if (!E || (Err && *Err))
- return LocData;
- if (SecNdx)
- *SecNdx = E->SectionIndex;
-
- uint64_t R =
- object::resolveRelocation(E->Resolver, E->Reloc, E->SymbolValue, LocData);
- if (E->Reloc2)
- R = object::resolveRelocation(E->Resolver, *E->Reloc2, E->SymbolValue2, R);
- return R;
-}
-
-std::optional<uint64_t>
-DWARFDataExtractor::getEncodedPointer(uint64_t *Offset, uint8_t Encoding,
- uint64_t PCRelOffset) const {
- if (Encoding == dwarf::DW_EH_PE_omit)
- return std::nullopt;
-
- uint64_t Result = 0;
- uint64_t OldOffset = *Offset;
- // First get value
- switch (Encoding & 0x0F) {
- case dwarf::DW_EH_PE_absptr:
- switch (getAddressSize()) {
- case 2:
- case 4:
- case 8:
- Result = getUnsigned(Offset, getAddressSize());
- break;
- default:
- return std::nullopt;
- }
- break;
- case dwarf::DW_EH_PE_uleb128:
- Result = getULEB128(Offset);
- break;
- case dwarf::DW_EH_PE_sleb128:
- Result = getSLEB128(Offset);
- break;
- case dwarf::DW_EH_PE_udata2:
- Result = getUnsigned(Offset, 2);
- break;
- case dwarf::DW_EH_PE_udata4:
- Result = getUnsigned(Offset, 4);
- break;
- case dwarf::DW_EH_PE_udata8:
- Result = getUnsigned(Offset, 8);
- break;
- case dwarf::DW_EH_PE_sdata2:
- Result = getSigned(Offset, 2);
- break;
- case dwarf::DW_EH_PE_sdata4:
- Result = SignExtend64<32>(getRelocatedValue(4, Offset));
- break;
- case dwarf::DW_EH_PE_sdata8:
- Result = getRelocatedValue(8, Offset);
- break;
- default:
- return std::nullopt;
- }
- // Then add relative offset, if required
- switch (Encoding & 0x70) {
- case dwarf::DW_EH_PE_absptr:
- // do nothing
- break;
- case dwarf::DW_EH_PE_pcrel:
- Result += PCRelOffset;
- break;
- case dwarf::DW_EH_PE_datarel:
- case dwarf::DW_EH_PE_textrel:
- case dwarf::DW_EH_PE_funcrel:
- case dwarf::DW_EH_PE_aligned:
- default:
- *Offset = OldOffset;
- return std::nullopt;
- }
-
- return Result;
-}
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