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llvm / llvm-project / 625273e7840cf4926f817dee14308dd54043cb15 / . / bolt / lib / Core / DebugData.cpp
blob: f1204925a98a4ea0ad476f750961c141e0c01f04 [file] [log] [blame]
//===- bolt/Core/DebugData.cpp - Debugging information handling -----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements functions and classes for handling debug info.
//
//===----------------------------------------------------------------------===//
#include "bolt/Core/DebugData.h"
#include "bolt/Core/BinaryContext.h"
#include "bolt/Rewrite/RewriteInstance.h"
#include "bolt/Utils/Utils.h"
#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugAddr.h"
#include "llvm/MC/MCAssembler.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectStreamer.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/SHA1.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <functional>
#include <limits>
#include <unordered_map>
#include <vector>
#define DEBUG_TYPE "bolt-debug-info"
namespace opts {
extern llvm::cl::opt<unsigned> Verbosity;
} // namespace opts
namespace llvm {
class MCSymbol;
namespace bolt {
std::optional<AttrInfo>
findAttributeInfo(const DWARFDie DIE,
const DWARFAbbreviationDeclaration *AbbrevDecl,
uint32_t Index) {
const DWARFUnit &U = *DIE.getDwarfUnit();
uint64_t Offset =
AbbrevDecl->getAttributeOffsetFromIndex(Index, DIE.getOffset(), U);
std::optional<DWARFFormValue> Value =
AbbrevDecl->getAttributeValueFromOffset(Index, Offset, U);
if (!Value)
return std::nullopt;
// AttributeSpec
const DWARFAbbreviationDeclaration::AttributeSpec *AttrVal =
AbbrevDecl->attributes().begin() + Index;
uint32_t ValSize = 0;
std::optional<int64_t> ValSizeOpt = AttrVal->getByteSize(U);
if (ValSizeOpt) {
ValSize = static_cast<uint32_t>(*ValSizeOpt);
} else {
DWARFDataExtractor DebugInfoData = U.getDebugInfoExtractor();
uint64_t NewOffset = Offset;
DWARFFormValue::skipValue(Value->getForm(), DebugInfoData, &NewOffset,
U.getFormParams());
// This includes entire size of the entry, which might not be just the
// encoding part. For example for DW_AT_loc it will include expression
// location.
ValSize = NewOffset - Offset;
}
return AttrInfo{*Value, DIE.getAbbreviationDeclarationPtr(), Offset, ValSize};
}
std::optional<AttrInfo> findAttributeInfo(const DWARFDie DIE,
dwarf::Attribute Attr) {
if (!DIE.isValid())
return std::nullopt;
const DWARFAbbreviationDeclaration *AbbrevDecl =
DIE.getAbbreviationDeclarationPtr();
if (!AbbrevDecl)
return std::nullopt;
std::optional<uint32_t> Index = AbbrevDecl->findAttributeIndex(Attr);
if (!Index)
return std::nullopt;
return findAttributeInfo(DIE, AbbrevDecl, *Index);
}
const DebugLineTableRowRef DebugLineTableRowRef::NULL_ROW{0, 0};
LLVM_ATTRIBUTE_UNUSED
static void printLE64(const std::string &S) {
for (uint32_t I = 0, Size = S.size(); I < Size; ++I) {
errs() << Twine::utohexstr(S[I]);
errs() << Twine::utohexstr((int8_t)S[I]);
}
errs() << "\n";
}
// Writes address ranges to Writer as pairs of 64-bit (address, size).
// If RelativeRange is true, assumes the address range to be written must be of
// the form (begin address, range size), otherwise (begin address, end address).
// Terminates the list by writing a pair of two zeroes.
// Returns the number of written bytes.
static uint64_t
writeAddressRanges(raw_svector_ostream &Stream,
const DebugAddressRangesVector &AddressRanges,
const bool WriteRelativeRanges = false) {
for (const DebugAddressRange &Range : AddressRanges) {
support::endian::write(Stream, Range.LowPC, support::little);
support::endian::write(
Stream, WriteRelativeRanges ? Range.HighPC - Range.LowPC : Range.HighPC,
support::little);
}
// Finish with 0 entries.
support::endian::write(Stream, 0ULL, support::little);
support::endian::write(Stream, 0ULL, support::little);
return AddressRanges.size() * 16 + 16;
}
DebugRangesSectionWriter::DebugRangesSectionWriter() {
RangesBuffer = std::make_unique<DebugBufferVector>();
RangesStream = std::make_unique<raw_svector_ostream>(*RangesBuffer);
// Add an empty range as the first entry;
SectionOffset +=
writeAddressRanges(*RangesStream.get(), DebugAddressRangesVector{});
Kind = RangesWriterKind::DebugRangesWriter;
}
uint64_t DebugRangesSectionWriter::addRanges(
DebugAddressRangesVector &&Ranges,
std::map<DebugAddressRangesVector, uint64_t> &CachedRanges) {
if (Ranges.empty())
return getEmptyRangesOffset();
const auto RI = CachedRanges.find(Ranges);
if (RI != CachedRanges.end())
return RI->second;
const uint64_t EntryOffset = addRanges(Ranges);
CachedRanges.emplace(std::move(Ranges), EntryOffset);
return EntryOffset;
}
uint64_t DebugRangesSectionWriter::addRanges(DebugAddressRangesVector &Ranges) {
if (Ranges.empty())
return getEmptyRangesOffset();
// Reading the SectionOffset and updating it should be atomic to guarantee
// unique and correct offsets in patches.
std::lock_guard<std::mutex> Lock(WriterMutex);
const uint32_t EntryOffset = SectionOffset;
SectionOffset += writeAddressRanges(*RangesStream.get(), Ranges);
return EntryOffset;
}
uint64_t DebugRangesSectionWriter::getSectionOffset() {
std::lock_guard<std::mutex> Lock(WriterMutex);
return SectionOffset;
}
DebugAddrWriter *DebugRangeListsSectionWriter::AddrWriter = nullptr;
uint64_t DebugRangeListsSectionWriter::addRanges(
DebugAddressRangesVector &&Ranges,
std::map<DebugAddressRangesVector, uint64_t> &CachedRanges) {
return addRanges(Ranges);
}
struct LocListsRangelistsHeader {
UnitLengthType UnitLength; // Size of loclist entris section, not including
// size of header.
VersionType Version;
AddressSizeType AddressSize;
SegmentSelectorType SegmentSelector;
OffsetEntryCountType OffsetEntryCount;
};
static std::unique_ptr<DebugBufferVector>
getDWARF5Header(const LocListsRangelistsHeader &Header) {
std::unique_ptr<DebugBufferVector> HeaderBuffer =
std::make_unique<DebugBufferVector>();
std::unique_ptr<raw_svector_ostream> HeaderStream =
std::make_unique<raw_svector_ostream>(*HeaderBuffer);
// 7.29 length of the set of entries for this compilation unit, not including
// the length field itself
const uint32_t HeaderSize =
getDWARF5RngListLocListHeaderSize() - sizeof(UnitLengthType);
support::endian::write(*HeaderStream, Header.UnitLength + HeaderSize,
support::little);
support::endian::write(*HeaderStream, Header.Version, support::little);
support::endian::write(*HeaderStream, Header.AddressSize, support::little);
support::endian::write(*HeaderStream, Header.SegmentSelector,
support::little);
support::endian::write(*HeaderStream, Header.OffsetEntryCount,
support::little);
return HeaderBuffer;
}
struct OffsetEntry {
uint32_t Index;
uint32_t StartOffset;
uint32_t EndOffset;
};
template <typename DebugVector, typename ListEntry, typename DebugAddressEntry>
static bool emitWithBase(raw_ostream &OS, const DebugVector &Entries,
DebugAddrWriter &AddrWriter, DWARFUnit &CU,
uint32_t &Index, const ListEntry BaseAddressx,
const ListEntry OffsetPair, const ListEntry EndOfList,
const std::function<void(uint32_t)> &Func) {
if (Entries.size() < 2)
return false;
uint64_t Base = Entries[Index].LowPC;
std::vector<OffsetEntry> Offsets;
uint8_t TempBuffer[64];
while (Index < Entries.size()) {
const DebugAddressEntry &Entry = Entries[Index];
if (Entry.LowPC == 0)
break;
assert(Base <= Entry.LowPC && "Entry base is higher than low PC");
uint32_t StartOffset = Entry.LowPC - Base;
uint32_t EndOffset = Entry.HighPC - Base;
if (encodeULEB128(EndOffset, TempBuffer) > 2)
break;
Offsets.push_back({Index, StartOffset, EndOffset});
++Index;
}
if (Offsets.size() < 2) {
Index -= Offsets.size();
return false;
}
support::endian::write(OS, static_cast<uint8_t>(BaseAddressx),
support::little);
uint32_t BaseIndex = AddrWriter.getIndexFromAddress(Base, CU);
encodeULEB128(BaseIndex, OS);
for (auto &OffsetEntry : Offsets) {
support::endian::write(OS, static_cast<uint8_t>(OffsetPair),
support::little);
encodeULEB128(OffsetEntry.StartOffset, OS);
encodeULEB128(OffsetEntry.EndOffset, OS);
Func(OffsetEntry.Index);
}
support::endian::write(OS, static_cast<uint8_t>(EndOfList), support::little);
return true;
}
uint64_t
DebugRangeListsSectionWriter::addRanges(DebugAddressRangesVector &Ranges) {
std::lock_guard<std::mutex> Lock(WriterMutex);
RangeEntries.push_back(CurrentOffset);
bool WrittenStartxLength = false;
std::sort(
Ranges.begin(), Ranges.end(),
[](const DebugAddressRange &R1, const DebugAddressRange &R2) -> bool {
return R1.LowPC < R2.LowPC;
});
for (unsigned I = 0; I < Ranges.size();) {
WrittenStartxLength = false;
if (emitWithBase<DebugAddressRangesVector, dwarf::RnglistEntries,
DebugAddressRange>(
*CUBodyStream, Ranges, *AddrWriter, *CU, I,
dwarf::DW_RLE_base_addressx, dwarf::DW_RLE_offset_pair,
dwarf::DW_RLE_end_of_list, [](uint32_t Index) -> void {}))
continue;
const DebugAddressRange &Range = Ranges[I];
support::endian::write(*CUBodyStream,
static_cast<uint8_t>(dwarf::DW_RLE_startx_length),
support::little);
uint32_t Index = AddrWriter->getIndexFromAddress(Range.LowPC, *CU);
encodeULEB128(Index, *CUBodyStream);
encodeULEB128(Range.HighPC - Range.LowPC, *CUBodyStream);
++I;
WrittenStartxLength = true;
}
if (WrittenStartxLength)
support::endian::write(*CUBodyStream,
static_cast<uint8_t>(dwarf::DW_RLE_end_of_list),
support::little);
CurrentOffset = CUBodyBuffer->size();
return RangeEntries.size() - 1;
}
void DebugRangeListsSectionWriter::finalizeSection() {
std::unique_ptr<DebugBufferVector> CUArrayBuffer =
std::make_unique<DebugBufferVector>();
std::unique_ptr<raw_svector_ostream> CUArrayStream =
std::make_unique<raw_svector_ostream>(*CUArrayBuffer);
constexpr uint32_t SizeOfArrayEntry = 4;
const uint32_t SizeOfArraySection = RangeEntries.size() * SizeOfArrayEntry;
for (uint32_t Offset : RangeEntries)
support::endian::write(*CUArrayStream, Offset + SizeOfArraySection,
support::little);
std::unique_ptr<DebugBufferVector> Header = getDWARF5Header(
{static_cast<uint32_t>(SizeOfArraySection + CUBodyBuffer.get()->size()),
5, 8, 0, static_cast<uint32_t>(RangeEntries.size())});
*RangesStream << *Header;
*RangesStream << *CUArrayBuffer;
*RangesStream << *CUBodyBuffer;
SectionOffset = RangesBuffer->size();
}
void DebugRangeListsSectionWriter::initSection(DWARFUnit &Unit) {
CUBodyBuffer = std::make_unique<DebugBufferVector>();
CUBodyStream = std::make_unique<raw_svector_ostream>(*CUBodyBuffer);
RangeEntries.clear();
CurrentOffset = 0;
CU = &Unit;
}
void DebugARangesSectionWriter::addCURanges(uint64_t CUOffset,
DebugAddressRangesVector &&Ranges) {
std::lock_guard<std::mutex> Lock(CUAddressRangesMutex);
CUAddressRanges.emplace(CUOffset, std::move(Ranges));
}
void DebugARangesSectionWriter::writeARangesSection(
raw_svector_ostream &RangesStream, const CUOffsetMap &CUMap) const {
// For reference on the format of the .debug_aranges section, see the DWARF4
// specification, section 6.1.4 Lookup by Address
// http://www.dwarfstd.org/doc/DWARF4.pdf
for (const auto &CUOffsetAddressRangesPair : CUAddressRanges) {
const uint64_t Offset = CUOffsetAddressRangesPair.first;
const DebugAddressRangesVector &AddressRanges =
CUOffsetAddressRangesPair.second;
// Emit header.
// Size of this set: 8 (size of the header) + 4 (padding after header)
// + 2*sizeof(uint64_t) bytes for each of the ranges, plus an extra
// pair of uint64_t's for the terminating, zero-length range.
// Does not include size field itself.
uint32_t Size = 8 + 4 + 2 * sizeof(uint64_t) * (AddressRanges.size() + 1);
// Header field #1: set size.
support::endian::write(RangesStream, Size, support::little);
// Header field #2: version number, 2 as per the specification.
support::endian::write(RangesStream, static_cast<uint16_t>(2),
support::little);
assert(CUMap.count(Offset) && "Original CU offset is not found in CU Map");
// Header field #3: debug info offset of the correspondent compile unit.
support::endian::write(
RangesStream, static_cast<uint32_t>(CUMap.find(Offset)->second.Offset),
support::little);
// Header field #4: address size.
// 8 since we only write ELF64 binaries for now.
RangesStream << char(8);
// Header field #5: segment size of target architecture.
RangesStream << char(0);
// Padding before address table - 4 bytes in the 64-bit-pointer case.
support::endian::write(RangesStream, static_cast<uint32_t>(0),
support::little);
writeAddressRanges(RangesStream, AddressRanges, true);
}
}
DebugAddrWriter::DebugAddrWriter(BinaryContext *Bc) { BC = Bc; }
void DebugAddrWriter::AddressForDWOCU::dump() {
std::vector<IndexAddressPair> SortedMap(indexToAddressBegin(),
indexToAdddessEnd());
// Sorting address in increasing order of indices.
llvm::sort(SortedMap, llvm::less_first());
for (auto &Pair : SortedMap)
dbgs() << Twine::utohexstr(Pair.second) << "\t" << Pair.first << "\n";
}
uint32_t DebugAddrWriter::getIndexFromAddress(uint64_t Address, DWARFUnit &CU) {
std::lock_guard<std::mutex> Lock(WriterMutex);
const uint64_t CUID = getCUID(CU);
if (!AddressMaps.count(CUID))
AddressMaps[CUID] = AddressForDWOCU();
AddressForDWOCU &Map = AddressMaps[CUID];
auto Entry = Map.find(Address);
if (Entry == Map.end()) {
auto Index = Map.getNextIndex();
Entry = Map.insert(Address, Index).first;
}
return Entry->second;
}
// Case1) Address is not in map insert in to AddresToIndex and IndexToAddres
// Case2) Address is in the map but Index is higher or equal. Need to update
// IndexToAddrss. Case3) Address is in the map but Index is lower. Need to
// update AddressToIndex and IndexToAddress
void DebugAddrWriter::addIndexAddress(uint64_t Address, uint32_t Index,
DWARFUnit &CU) {
std::lock_guard<std::mutex> Lock(WriterMutex);
const uint64_t CUID = getCUID(CU);
AddressForDWOCU &Map = AddressMaps[CUID];
auto Entry = Map.find(Address);
if (Entry != Map.end()) {
if (Entry->second > Index)
Map.updateAddressToIndex(Address, Index);
Map.updateIndexToAddrss(Address, Index);
} else {
Map.insert(Address, Index);
}
}
AddressSectionBuffer DebugAddrWriter::finalize() {
// Need to layout all sections within .debug_addr
// Within each section sort Address by index.
AddressSectionBuffer Buffer;
raw_svector_ostream AddressStream(Buffer);
for (std::unique_ptr<DWARFUnit> &CU : BC->DwCtx->compile_units()) {
// Handling the case wehre debug information is a mix of Debug fission and
// monolitic.
if (!CU->getDWOId())
continue;
const uint64_t CUID = getCUID(*CU.get());
auto AM = AddressMaps.find(CUID);
// Adding to map even if it did not contribute to .debug_addr.
// The Skeleton CU might still have DW_AT_GNU_addr_base.
DWOIdToOffsetMap[CUID] = Buffer.size();
// If does not exist this CUs DWO section didn't contribute to .debug_addr.
if (AM == AddressMaps.end())
continue;
std::vector<IndexAddressPair> SortedMap(AM->second.indexToAddressBegin(),
AM->second.indexToAdddessEnd());
// Sorting address in increasing order of indices.
llvm::sort(SortedMap, llvm::less_first());
uint8_t AddrSize = CU->getAddressByteSize();
uint32_t Counter = 0;
auto WriteAddress = [&](uint64_t Address) -> void {
++Counter;
switch (AddrSize) {
default:
assert(false && "Address Size is invalid.");
break;
case 4:
support::endian::write(AddressStream, static_cast<uint32_t>(Address),
support::little);
break;
case 8:
support::endian::write(AddressStream, Address, support::little);
break;
}
};
for (const IndexAddressPair &Val : SortedMap) {
while (Val.first > Counter)
WriteAddress(0);
WriteAddress(Val.second);
}
}
return Buffer;
}
AddressSectionBuffer DebugAddrWriterDwarf5::finalize() {
// Need to layout all sections within .debug_addr
// Within each section sort Address by index.
AddressSectionBuffer Buffer;
raw_svector_ostream AddressStream(Buffer);
const endianness Endian =
BC->DwCtx->isLittleEndian() ? support::little : support::big;
const DWARFSection &AddrSec = BC->DwCtx->getDWARFObj().getAddrSection();
DWARFDataExtractor AddrData(BC->DwCtx->getDWARFObj(), AddrSec, Endian, 0);
DWARFDebugAddrTable AddrTable;
DIDumpOptions DumpOpts;
constexpr uint32_t HeaderSize = 8;
DenseMap<uint64_t, uint64_t> UnmodifiedAddressOffsets;
for (std::unique_ptr<DWARFUnit> &CU : BC->DwCtx->compile_units()) {
const uint64_t CUID = getCUID(*CU.get());
const uint8_t AddrSize = CU->getAddressByteSize();
auto AMIter = AddressMaps.find(CUID);
// A case where CU has entry in .debug_addr, but we don't modify addresses
// for it.
if (AMIter == AddressMaps.end()) {
AMIter = AddressMaps.insert({CUID, AddressForDWOCU()}).first;
std::optional<uint64_t> BaseOffset = CU->getAddrOffsetSectionBase();
if (!BaseOffset)
continue;
// Address base offset is to the first entry.
// The size of header is 8 bytes.
uint64_t Offset = *BaseOffset - HeaderSize;
auto Iter = UnmodifiedAddressOffsets.find(Offset);
if (Iter != UnmodifiedAddressOffsets.end()) {
DWOIdToOffsetMap[CUID] = Iter->getSecond();
continue;
}
UnmodifiedAddressOffsets[Offset] = Buffer.size() + HeaderSize;
if (Error Err = AddrTable.extract(AddrData, &Offset, 5, AddrSize,
DumpOpts.WarningHandler)) {
DumpOpts.RecoverableErrorHandler(std::move(Err));
continue;
}
uint32_t Index = 0;
for (uint64_t Addr : AddrTable.getAddressEntries())
AMIter->second.insert(Addr, Index++);
}
DWOIdToOffsetMap[CUID] = Buffer.size() + HeaderSize;
std::vector<IndexAddressPair> SortedMap(
AMIter->second.indexToAddressBegin(),
AMIter->second.indexToAdddessEnd());
// Sorting address in increasing order of indices.
llvm::sort(SortedMap, llvm::less_first());
// Writing out Header
const uint32_t Length = SortedMap.size() * AddrSize + 4;
support::endian::write(AddressStream, Length, Endian);
support::endian::write(AddressStream, static_cast<uint16_t>(5), Endian);
support::endian::write(AddressStream, static_cast<uint8_t>(AddrSize),
Endian);
support::endian::write(AddressStream, static_cast<uint8_t>(0), Endian);
uint32_t Counter = 0;
auto writeAddress = [&](uint64_t Address) -> void {
++Counter;
switch (AddrSize) {
default:
llvm_unreachable("Address Size is invalid.");
break;
case 4:
support::endian::write(AddressStream, static_cast<uint32_t>(Address),
Endian);
break;
case 8:
support::endian::write(AddressStream, Address, Endian);
break;
}
};
for (const IndexAddressPair &Val : SortedMap) {
while (Val.first > Counter)
writeAddress(0);
writeAddress(Val.second);
}
}
return Buffer;
}
uint64_t DebugAddrWriter::getOffset(DWARFUnit &Unit) {
const uint64_t CUID = getCUID(Unit);
assert(CUID && "Can't get offset, not a skeleton CU.");
auto Iter = DWOIdToOffsetMap.find(CUID);
assert(Iter != DWOIdToOffsetMap.end() &&
"Offset in to.debug_addr was not found for DWO ID.");
return Iter->second;
}
uint64_t DebugAddrWriterDwarf5::getOffset(DWARFUnit &Unit) {
auto Iter = DWOIdToOffsetMap.find(getCUID(Unit));
assert(Iter != DWOIdToOffsetMap.end() &&
"Offset in to.debug_addr was not found for CU ID.");
return Iter->second;
}
void DebugLocWriter::init() {
LocBuffer = std::make_unique<DebugBufferVector>();
LocStream = std::make_unique<raw_svector_ostream>(*LocBuffer);
// Writing out empty location list to which all references to empty location
// lists will point.
if (!LocSectionOffset && DwarfVersion < 5) {
const char Zeroes[16] = {0};
*LocStream << StringRef(Zeroes, 16);
LocSectionOffset += 16;
}
}
uint32_t DebugLocWriter::LocSectionOffset = 0;
void DebugLocWriter::addList(AttrInfo &AttrVal, DebugLocationsVector &LocList,
DebugInfoBinaryPatcher &DebugInfoPatcher,
DebugAbbrevWriter &AbbrevWriter) {
const uint64_t AttrOffset = AttrVal.Offset;
if (LocList.empty()) {
DebugInfoPatcher.addLE32Patch(AttrOffset, DebugLocWriter::EmptyListOffset);
return;
}
// Since there is a separate DebugLocWriter for each thread,
// we don't need a lock to read the SectionOffset and update it.
const uint32_t EntryOffset = LocSectionOffset;
for (const DebugLocationEntry &Entry : LocList) {
support::endian::write(*LocStream, static_cast<uint64_t>(Entry.LowPC),
support::little);
support::endian::write(*LocStream, static_cast<uint64_t>(Entry.HighPC),
support::little);
support::endian::write(*LocStream, static_cast<uint16_t>(Entry.Expr.size()),
support::little);
*LocStream << StringRef(reinterpret_cast<const char *>(Entry.Expr.data()),
Entry.Expr.size());
LocSectionOffset += 2 * 8 + 2 + Entry.Expr.size();
}
LocStream->write_zeros(16);
LocSectionOffset += 16;
LocListDebugInfoPatches.push_back({AttrOffset, EntryOffset});
DebugInfoPatcher.addLE32Patch(AttrOffset, EntryOffset);
}
std::unique_ptr<DebugBufferVector> DebugLocWriter::getBuffer() {
return std::move(LocBuffer);
}
// DWARF 4: 2.6.2
void DebugLocWriter::finalize(DebugInfoBinaryPatcher &DebugInfoPatcher,
DebugAbbrevWriter &AbbrevWriter) {}
static void writeEmptyListDwarf5(raw_svector_ostream &Stream) {
support::endian::write(Stream, static_cast<uint32_t>(4), support::little);
support::endian::write(Stream, static_cast<uint8_t>(dwarf::DW_LLE_start_end),
support::little);
const char Zeroes[16] = {0};
Stream << StringRef(Zeroes, 16);
encodeULEB128(0, Stream);
support::endian::write(
Stream, static_cast<uint8_t>(dwarf::DW_LLE_end_of_list), support::little);
}
static void writeLegacyLocList(AttrInfo &AttrVal, DebugLocationsVector &LocList,
DebugInfoBinaryPatcher &DebugInfoPatcher,
DebugAddrWriter &AddrWriter,
DebugBufferVector &LocBuffer, DWARFUnit &CU,
raw_svector_ostream &LocStream) {
const uint64_t AttrOffset = AttrVal.Offset;
if (LocList.empty()) {
DebugInfoPatcher.addLE32Patch(AttrOffset, DebugLocWriter::EmptyListOffset);
return;
}
const uint32_t EntryOffset = LocBuffer.size();
for (const DebugLocationEntry &Entry : LocList) {
support::endian::write(LocStream,
static_cast<uint8_t>(dwarf::DW_LLE_startx_length),
support::little);
const uint32_t Index = AddrWriter.getIndexFromAddress(Entry.LowPC, CU);
encodeULEB128(Index, LocStream);
support::endian::write(LocStream,
static_cast<uint32_t>(Entry.HighPC - Entry.LowPC),
support::little);
support::endian::write(LocStream, static_cast<uint16_t>(Entry.Expr.size()),
support::little);
LocStream << StringRef(reinterpret_cast<const char *>(Entry.Expr.data()),
Entry.Expr.size());
}
support::endian::write(LocStream,
static_cast<uint8_t>(dwarf::DW_LLE_end_of_list),
support::little);
DebugInfoPatcher.addLE32Patch(AttrOffset, EntryOffset);
}
static void writeDWARF5LocList(
uint32_t &NumberOfEntries, AttrInfo &AttrVal, DebugLocationsVector &LocList,
DebugInfoBinaryPatcher &DebugInfoPatcher, DebugAbbrevWriter &AbbrevWriter,
DebugAddrWriter &AddrWriter, DebugBufferVector &LocBodyBuffer,
std::vector<uint32_t> &RelativeLocListOffsets, DWARFUnit &CU,
raw_svector_ostream &LocBodyStream) {
if (AttrVal.V.getForm() != dwarf::DW_FORM_loclistx) {
AbbrevWriter.addAttributePatch(CU, AttrVal.AbbrevDecl,
dwarf::DW_AT_location, dwarf::DW_AT_location,
dwarf::DW_FORM_loclistx);
}
DebugInfoPatcher.addUDataPatch(AttrVal.Offset, NumberOfEntries, AttrVal.Size);
RelativeLocListOffsets.push_back(LocBodyBuffer.size());
++NumberOfEntries;
if (LocList.empty()) {
writeEmptyListDwarf5(LocBodyStream);
return;
}
std::vector<uint64_t> OffsetsArray;
bool WrittenStartxLength = false;
auto writeExpression = [&](uint32_t Index) -> void {
const DebugLocationEntry &Entry = LocList[Index];
encodeULEB128(Entry.Expr.size(), LocBodyStream);
LocBodyStream << StringRef(
reinterpret_cast<const char *>(Entry.Expr.data()), Entry.Expr.size());
};
for (unsigned I = 0; I < LocList.size();) {
WrittenStartxLength = false;
if (emitWithBase<DebugLocationsVector, dwarf::LoclistEntries,
DebugLocationEntry>(
LocBodyStream, LocList, AddrWriter, CU, I,
dwarf::DW_LLE_base_addressx, dwarf::DW_LLE_offset_pair,
dwarf::DW_LLE_end_of_list, writeExpression))
continue;
const DebugLocationEntry &Entry = LocList[I];
support::endian::write(LocBodyStream,
static_cast<uint8_t>(dwarf::DW_LLE_startx_length),
support::little);
const uint32_t Index = AddrWriter.getIndexFromAddress(Entry.LowPC, CU);
encodeULEB128(Index, LocBodyStream);
encodeULEB128(Entry.HighPC - Entry.LowPC, LocBodyStream);
writeExpression(I);
++I;
WrittenStartxLength = true;
}
if (WrittenStartxLength)
support::endian::write(LocBodyStream,
static_cast<uint8_t>(dwarf::DW_LLE_end_of_list),
support::little);
}
void DebugLoclistWriter::addList(AttrInfo &AttrVal,
DebugLocationsVector &LocList,
DebugInfoBinaryPatcher &DebugInfoPatcher,
DebugAbbrevWriter &AbbrevWriter) {
if (DwarfVersion < 5)
writeLegacyLocList(AttrVal, LocList, DebugInfoPatcher, *AddrWriter,
*LocBuffer, CU, *LocStream);
else
writeDWARF5LocList(NumberOfEntries, AttrVal, LocList, DebugInfoPatcher,
AbbrevWriter, *AddrWriter, *LocBodyBuffer,
RelativeLocListOffsets, CU, *LocBodyStream);
}
uint32_t DebugLoclistWriter::LoclistBaseOffset = 0;
void DebugLoclistWriter::finalizeDWARF5(
DebugInfoBinaryPatcher &DebugInfoPatcher, DebugAbbrevWriter &AbbrevWriter) {
if (LocBodyBuffer->empty()) {
std::optional<AttrInfo> AttrInfoVal =
findAttributeInfo(CU.getUnitDIE(), dwarf::DW_AT_loclists_base);
// Pointing to first one, because it doesn't matter. There are no uses of it
// in this CU.
if (!isSplitDwarf() && AttrInfoVal)
DebugInfoPatcher.addLE32Patch(AttrInfoVal->Offset,
getDWARF5RngListLocListHeaderSize());
return;
}
std::unique_ptr<DebugBufferVector> LocArrayBuffer =
std::make_unique<DebugBufferVector>();
std::unique_ptr<raw_svector_ostream> LocArrayStream =
std::make_unique<raw_svector_ostream>(*LocArrayBuffer);
const uint32_t SizeOfArraySection = NumberOfEntries * sizeof(uint32_t);
// Write out IndexArray
for (uint32_t RelativeOffset : RelativeLocListOffsets)
support::endian::write(
*LocArrayStream,
static_cast<uint32_t>(SizeOfArraySection + RelativeOffset),
support::little);
std::unique_ptr<DebugBufferVector> Header = getDWARF5Header(
{static_cast<uint32_t>(SizeOfArraySection + LocBodyBuffer.get()->size()),
5, 8, 0, NumberOfEntries});
*LocStream << *Header;
*LocStream << *LocArrayBuffer;
*LocStream << *LocBodyBuffer;
if (!isSplitDwarf()) {
if (std::optional<AttrInfo> AttrInfoVal =
findAttributeInfo(CU.getUnitDIE(), dwarf::DW_AT_loclists_base))
DebugInfoPatcher.addLE32Patch(AttrInfoVal->Offset,
LoclistBaseOffset +
getDWARF5RngListLocListHeaderSize());
else {
AbbrevWriter.addAttribute(
CU, CU.getUnitDIE().getAbbreviationDeclarationPtr(),
dwarf::DW_AT_loclists_base, dwarf::DW_FORM_sec_offset);
DebugInfoPatcher.insertNewEntry(CU.getUnitDIE(),
LoclistBaseOffset + Header->size());
}
LoclistBaseOffset += LocBuffer->size();
}
clearList(RelativeLocListOffsets);
clearList(*LocArrayBuffer);
clearList(*LocBodyBuffer);
}
void DebugLoclistWriter::finalize(DebugInfoBinaryPatcher &DebugInfoPatcher,
DebugAbbrevWriter &AbbrevWriter) {
if (DwarfVersion >= 5)
finalizeDWARF5(DebugInfoPatcher, AbbrevWriter);
}
DebugAddrWriter *DebugLoclistWriter::AddrWriter = nullptr;
void DebugInfoBinaryPatcher::addUnitBaseOffsetLabel(uint64_t Offset) {
Offset -= DWPUnitOffset;
std::lock_guard<std::mutex> Lock(WriterMutex);
DebugPatches.emplace_back(new DWARFUnitOffsetBaseLabel(Offset));
}
void DebugInfoBinaryPatcher::addDestinationReferenceLabel(uint64_t Offset) {
Offset -= DWPUnitOffset;
std::lock_guard<std::mutex> Lock(WriterMutex);
auto RetVal = DestinationLabels.insert(Offset);
if (!RetVal.second)
return;
DebugPatches.emplace_back(new DestinationReferenceLabel(Offset));
}
static std::string encodeLE(size_t ByteSize, uint64_t NewValue) {
std::string LE64(ByteSize, 0);
for (size_t I = 0; I < ByteSize; ++I) {
LE64[I] = NewValue & 0xff;
NewValue >>= 8;
}
return LE64;
}
void DebugInfoBinaryPatcher::insertNewEntry(const DWARFDie &DIE,
uint32_t Value) {
std::string StrValue = encodeLE(4, Value);
insertNewEntry(DIE, std::move(StrValue));
}
void DebugInfoBinaryPatcher::insertNewEntry(const DWARFDie &DIE,
std::string &&Value) {
const DWARFAbbreviationDeclaration *AbbrevDecl =
DIE.getAbbreviationDeclarationPtr();
// In case this DIE has no attributes.
uint32_t Offset = DIE.getOffset() + 1;
size_t NumOfAttributes = AbbrevDecl->getNumAttributes();
if (NumOfAttributes) {
std::optional<AttrInfo> Val =
findAttributeInfo(DIE, AbbrevDecl, NumOfAttributes - 1);
assert(Val && "Invalid Value.");
Offset = Val->Offset + Val->Size - DWPUnitOffset;
}
std::lock_guard<std::mutex> Lock(WriterMutex);
DebugPatches.emplace_back(new NewDebugEntry(Offset, std::move(Value)));
}
void DebugInfoBinaryPatcher::addReferenceToPatch(uint64_t Offset,
uint32_t DestinationOffset,
uint32_t OldValueSize,
dwarf::Form Form) {
Offset -= DWPUnitOffset;
DestinationOffset -= DWPUnitOffset;
std::lock_guard<std::mutex> Lock(WriterMutex);
DebugPatches.emplace_back(
new DebugPatchReference(Offset, OldValueSize, DestinationOffset, Form));
}
void DebugInfoBinaryPatcher::addUDataPatch(uint64_t Offset, uint64_t NewValue,
uint32_t OldValueSize) {
Offset -= DWPUnitOffset;
std::lock_guard<std::mutex> Lock(WriterMutex);
DebugPatches.emplace_back(
new DebugPatchVariableSize(Offset, OldValueSize, NewValue));
}
void DebugInfoBinaryPatcher::addLE64Patch(uint64_t Offset, uint64_t NewValue) {
Offset -= DWPUnitOffset;
std::lock_guard<std::mutex> Lock(WriterMutex);
DebugPatches.emplace_back(new DebugPatch64(Offset, NewValue));
}
void DebugInfoBinaryPatcher::addLE32Patch(uint64_t Offset, uint32_t NewValue,
uint32_t OldValueSize) {
Offset -= DWPUnitOffset;
std::lock_guard<std::mutex> Lock(WriterMutex);
if (OldValueSize == 4)
DebugPatches.emplace_back(new DebugPatch32(Offset, NewValue));
else if (OldValueSize == 8)
DebugPatches.emplace_back(new DebugPatch64to32(Offset, NewValue));
else
DebugPatches.emplace_back(
new DebugPatch32GenericSize(Offset, NewValue, OldValueSize));
}
void SimpleBinaryPatcher::addBinaryPatch(uint64_t Offset,
std::string &&NewValue,
uint32_t OldValueSize) {
Patches.emplace_back(Offset, std::move(NewValue));
}
void SimpleBinaryPatcher::addBytePatch(uint64_t Offset, uint8_t Value) {
auto Str = std::string(1, Value);
Patches.emplace_back(Offset, std::move(Str));
}
void SimpleBinaryPatcher::addLEPatch(uint64_t Offset, uint64_t NewValue,
size_t ByteSize) {
Patches.emplace_back(Offset, encodeLE(ByteSize, NewValue));
}
void SimpleBinaryPatcher::addUDataPatch(uint64_t Offset, uint64_t Value,
uint32_t OldValueSize) {
std::string Buff;
raw_string_ostream OS(Buff);
encodeULEB128(Value, OS, OldValueSize);
Patches.emplace_back(Offset, std::move(Buff));
}
void SimpleBinaryPatcher::addLE64Patch(uint64_t Offset, uint64_t NewValue) {
addLEPatch(Offset, NewValue, 8);
}
void SimpleBinaryPatcher::addLE32Patch(uint64_t Offset, uint32_t NewValue,
uint32_t OldValueSize) {
addLEPatch(Offset, NewValue, 4);
}
std::string SimpleBinaryPatcher::patchBinary(StringRef BinaryContents) {
std::string BinaryContentsStr = std::string(BinaryContents);
for (const auto &Patch : Patches) {
uint32_t Offset = Patch.first;
const std::string &ByteSequence = Patch.second;
assert(Offset + ByteSequence.size() <= BinaryContents.size() &&
"Applied patch runs over binary size.");
for (uint64_t I = 0, Size = ByteSequence.size(); I < Size; ++I) {
BinaryContentsStr[Offset + I] = ByteSequence[I];
}
}
return BinaryContentsStr;
}
CUOffsetMap DebugInfoBinaryPatcher::computeNewOffsets(DWARFContext &DWCtx,
bool IsDWOContext) {
CUOffsetMap CUMap;
llvm::sort(DebugPatches, [](const UniquePatchPtrType &V1,
const UniquePatchPtrType &V2) {
if (V1.get()->Offset == V2.get()->Offset) {
if (V1->Kind == DebugPatchKind::NewDebugEntry &&
V2->Kind == DebugPatchKind::NewDebugEntry)
return reinterpret_cast<const NewDebugEntry *>(V1.get())->CurrentOrder <
reinterpret_cast<const NewDebugEntry *>(V2.get())->CurrentOrder;
// This is a case where we are modifying first entry of next
// DIE, and adding a new one.
return V1->Kind == DebugPatchKind::NewDebugEntry;
}
return V1.get()->Offset < V2.get()->Offset;
});
DWARFUnitVector::compile_unit_range CompileUnits =
IsDWOContext ? DWCtx.dwo_compile_units() : DWCtx.compile_units();
for (const std::unique_ptr<DWARFUnit> &CU : CompileUnits)
CUMap[CU->getOffset()] = {static_cast<uint32_t>(CU->getOffset()),
static_cast<uint32_t>(CU->getLength())};
// Calculating changes in .debug_info size from Patches to build a map of old
// to updated reference destination offsets.
uint32_t PreviousOffset = 0;
int32_t PreviousChangeInSize = 0;
for (UniquePatchPtrType &PatchBase : DebugPatches) {
Patch *P = PatchBase.get();
switch (P->Kind) {
default:
continue;
case DebugPatchKind::PatchValue64to32: {
PreviousChangeInSize -= 4;
break;
}
case DebugPatchKind::PatchValue32GenericSize: {
DebugPatch32GenericSize *DPVS =
reinterpret_cast<DebugPatch32GenericSize *>(P);
PreviousChangeInSize += 4 - DPVS->OldValueSize;
break;
}
case DebugPatchKind::PatchValueVariable: {
DebugPatchVariableSize *DPV =
reinterpret_cast<DebugPatchVariableSize *>(P);
std::string Temp;
raw_string_ostream OS(Temp);
encodeULEB128(DPV->Value, OS);
PreviousChangeInSize += Temp.size() - DPV->OldValueSize;
break;
}
case DebugPatchKind::DestinationReferenceLabel: {
DestinationReferenceLabel *DRL =
reinterpret_cast<DestinationReferenceLabel *>(P);
OldToNewOffset[DRL->Offset] =
DRL->Offset + ChangeInSize + PreviousChangeInSize;
break;
}
case DebugPatchKind::ReferencePatchValue: {
// This doesn't look to be a common case, so will always encode as 4 bytes
// to reduce algorithmic complexity.
DebugPatchReference *RDP = reinterpret_cast<DebugPatchReference *>(P);
if (RDP->PatchInfo.IndirectRelative) {
PreviousChangeInSize += 4 - RDP->PatchInfo.OldValueSize;
assert(RDP->PatchInfo.OldValueSize <= 4 &&
"Variable encoding reference greater than 4 bytes.");
}
break;
}
case DebugPatchKind::DWARFUnitOffsetBaseLabel: {
DWARFUnitOffsetBaseLabel *BaseLabel =
reinterpret_cast<DWARFUnitOffsetBaseLabel *>(P);
uint32_t CUOffset = BaseLabel->Offset;
ChangeInSize += PreviousChangeInSize;
uint32_t CUOffsetUpdate = CUOffset + ChangeInSize;
CUMap[CUOffset].Offset = CUOffsetUpdate;
CUMap[PreviousOffset].Length += PreviousChangeInSize;
PreviousChangeInSize = 0;
PreviousOffset = CUOffset;
break;
}
case DebugPatchKind::NewDebugEntry: {
NewDebugEntry *NDE = reinterpret_cast<NewDebugEntry *>(P);
PreviousChangeInSize += NDE->Value.size();
break;
}
}
}
CUMap[PreviousOffset].Length += PreviousChangeInSize;
return CUMap;
}
uint32_t DebugInfoBinaryPatcher::NewDebugEntry::OrderCounter = 0;
std::string DebugInfoBinaryPatcher::patchBinary(StringRef BinaryContents) {
std::string NewBinaryContents;
NewBinaryContents.reserve(BinaryContents.size() + ChangeInSize);
uint32_t StartOffset = 0;
uint32_t DwarfUnitBaseOffset = 0;
uint32_t OldValueSize = 0;
uint32_t Offset = 0;
std::string ByteSequence;
std::vector<std::pair<uint32_t, uint32_t>> LengthPatches;
// Wasting one entry to avoid checks for first.
LengthPatches.push_back({0, 0});
// Applying all the patches replacing current entry.
// This might change the size of .debug_info section.
for (const UniquePatchPtrType &PatchBase : DebugPatches) {
Patch *P = PatchBase.get();
switch (P->Kind) {
default:
continue;
case DebugPatchKind::ReferencePatchValue: {
DebugPatchReference *RDP = reinterpret_cast<DebugPatchReference *>(P);
uint32_t DestinationOffset = RDP->DestinationOffset;
assert(OldToNewOffset.count(DestinationOffset) &&
"Destination Offset for reference not updated.");
uint32_t UpdatedOffset = OldToNewOffset[DestinationOffset];
Offset = RDP->Offset;
OldValueSize = RDP->PatchInfo.OldValueSize;
if (RDP->PatchInfo.DirectRelative) {
UpdatedOffset -= DwarfUnitBaseOffset;
ByteSequence = encodeLE(OldValueSize, UpdatedOffset);
// In theory reference for DW_FORM_ref{1,2,4,8} can be right on the edge
// and overflow if later debug information grows.
if (ByteSequence.size() > OldValueSize)
errs() << "BOLT-ERROR: Relative reference of size "
<< Twine::utohexstr(OldValueSize)
<< " overflows with the new encoding.\n";
} else if (RDP->PatchInfo.DirectAbsolute) {
ByteSequence = encodeLE(OldValueSize, UpdatedOffset);
} else if (RDP->PatchInfo.IndirectRelative) {
UpdatedOffset -= DwarfUnitBaseOffset;
ByteSequence.clear();
raw_string_ostream OS(ByteSequence);
encodeULEB128(UpdatedOffset, OS, 4);
} else {
llvm_unreachable("Invalid Reference form.");
}
break;
}
case DebugPatchKind::PatchValue32: {
DebugPatch32 *P32 = reinterpret_cast<DebugPatch32 *>(P);
Offset = P32->Offset;
OldValueSize = 4;
ByteSequence = encodeLE(4, P32->Value);
break;
}
case DebugPatchKind::PatchValue64to32: {
DebugPatch64to32 *P64to32 = reinterpret_cast<DebugPatch64to32 *>(P);
Offset = P64to32->Offset;
OldValueSize = 8;
ByteSequence = encodeLE(4, P64to32->Value);
break;
}
case DebugPatchKind::PatchValue32GenericSize: {
DebugPatch32GenericSize *DPVS =
reinterpret_cast<DebugPatch32GenericSize *>(P);
Offset = DPVS->Offset;
OldValueSize = DPVS->OldValueSize;
ByteSequence = encodeLE(4, DPVS->Value);
break;
}
case DebugPatchKind::PatchValueVariable: {
DebugPatchVariableSize *PV =
reinterpret_cast<DebugPatchVariableSize *>(P);
Offset = PV->Offset;
OldValueSize = PV->OldValueSize;
ByteSequence.clear();
raw_string_ostream OS(ByteSequence);
encodeULEB128(PV->Value, OS);
break;
}
case DebugPatchKind::PatchValue64: {
DebugPatch64 *P64 = reinterpret_cast<DebugPatch64 *>(P);
Offset = P64->Offset;
OldValueSize = 8;
ByteSequence = encodeLE(8, P64->Value);
break;
}
case DebugPatchKind::DWARFUnitOffsetBaseLabel: {
DWARFUnitOffsetBaseLabel *BaseLabel =
reinterpret_cast<DWARFUnitOffsetBaseLabel *>(P);
Offset = BaseLabel->Offset;
OldValueSize = 0;
ByteSequence.clear();
auto &Patch = LengthPatches.back();
// Length to copy between last patch entry and next compile unit.
uint32_t RemainingLength = Offset - StartOffset;
uint32_t NewCUOffset = NewBinaryContents.size() + RemainingLength;
DwarfUnitBaseOffset = NewCUOffset;
// Length of previous CU = This CU Offset - sizeof(length) - last CU
// Offset.
Patch.second = NewCUOffset - 4 - Patch.first;
LengthPatches.push_back({NewCUOffset, 0});
break;
}
case DebugPatchKind::NewDebugEntry: {
NewDebugEntry *NDE = reinterpret_cast<NewDebugEntry *>(P);
Offset = NDE->Offset;
OldValueSize = 0;
ByteSequence = NDE->Value;
break;
}
}
assert((P->Kind == DebugPatchKind::NewDebugEntry ||
Offset + ByteSequence.size() <= BinaryContents.size()) &&
"Applied patch runs over binary size.");
uint32_t Length = Offset - StartOffset;
NewBinaryContents.append(BinaryContents.substr(StartOffset, Length).data(),
Length);
NewBinaryContents.append(ByteSequence.data(), ByteSequence.size());
StartOffset = Offset + OldValueSize;
}
uint32_t Length = BinaryContents.size() - StartOffset;
NewBinaryContents.append(BinaryContents.substr(StartOffset, Length).data(),
Length);
DebugPatches.clear();
// Patching lengths of CUs
auto &Patch = LengthPatches.back();
Patch.second = NewBinaryContents.size() - 4 - Patch.first;
for (uint32_t J = 1, Size = LengthPatches.size(); J < Size; ++J) {
const auto &Patch = LengthPatches[J];
ByteSequence = encodeLE(4, Patch.second);
Offset = Patch.first;
for (uint64_t I = 0, Size = ByteSequence.size(); I < Size; ++I)
NewBinaryContents[Offset + I] = ByteSequence[I];
}
return NewBinaryContents;
}
void DebugStrOffsetsWriter::initialize(
const DWARFSection &StrOffsetsSection,
const std::optional<StrOffsetsContributionDescriptor> Contr) {
if (!Contr)
return;
const uint8_t DwarfOffsetByteSize = Contr->getDwarfOffsetByteSize();
assert(DwarfOffsetByteSize == 4 &&
"Dwarf String Offsets Byte Size is not supported.");
uint32_t Index = 0;
for (uint64_t Offset = 0; Offset < Contr->Size; Offset += DwarfOffsetByteSize)
IndexToAddressMap[Index++] = support::endian::read32le(
StrOffsetsSection.Data.data() + Contr->Base + Offset);
}
void DebugStrOffsetsWriter::updateAddressMap(uint32_t Index, uint32_t Address) {
assert(IndexToAddressMap.count(Index) > 0 && "Index is not found.");
IndexToAddressMap[Index] = Address;
StrOffsetSectionWasModified = true;
}
void DebugStrOffsetsWriter::finalizeSection(DWARFUnit &Unit) {
if (IndexToAddressMap.empty())
return;
std::optional<AttrInfo> AttrVal =
findAttributeInfo(Unit.getUnitDIE(), dwarf::DW_AT_str_offsets_base);
assert(AttrVal && "DW_AT_str_offsets_base not present.");
std::optional<uint64_t> Val = AttrVal->V.getAsSectionOffset();
assert(Val && "DW_AT_str_offsets_base Value not present.");
auto RetVal = ProcessedBaseOffsets.insert(*Val);
if (RetVal.second) {
// Writing out the header for each section.
support::endian::write(*StrOffsetsStream, CurrentSectionSize + 4,
support::little);
support::endian::write(*StrOffsetsStream, static_cast<uint16_t>(5),
support::little);
support::endian::write(*StrOffsetsStream, static_cast<uint16_t>(0),
support::little);
for (const auto &Entry : IndexToAddressMap)
support::endian::write(*StrOffsetsStream, Entry.second, support::little);
}
// Will print error if we already processed this contribution, and now
// skipping it, but it was modified.
if (!RetVal.second && StrOffsetSectionWasModified)
errs() << "BOLT-WARNING: skipping string offsets section for CU at offset "
<< Twine::utohexstr(Unit.getOffset()) << ", but it was modified\n";
StrOffsetSectionWasModified = false;
IndexToAddressMap.clear();
}
void DebugStrWriter::create() {
StrBuffer = std::make_unique<DebugStrBufferVector>();
StrStream = std::make_unique<raw_svector_ostream>(*StrBuffer);
}
void DebugStrWriter::initialize() {
auto StrSection = BC.DwCtx->getDWARFObj().getStrSection();
(*StrStream) << StrSection;
}
uint32_t DebugStrWriter::addString(StringRef Str) {
std::lock_guard<std::mutex> Lock(WriterMutex);
if (StrBuffer->empty())
initialize();
auto Offset = StrBuffer->size();
(*StrStream) << Str;
StrStream->write_zeros(1);
return Offset;
}
void DebugAbbrevWriter::addUnitAbbreviations(DWARFUnit &Unit) {
const DWARFAbbreviationDeclarationSet *Abbrevs = Unit.getAbbreviations();
if (!Abbrevs)
return;
const PatchesTy &UnitPatches = Patches[&Unit];
const AbbrevEntryTy &AbbrevEntries = NewAbbrevEntries[&Unit];
// We are duplicating abbrev sections, to handle the case where for one CU we
// modify it, but for another we don't.
auto UnitDataPtr = std::make_unique<AbbrevData>();
AbbrevData &UnitData = *UnitDataPtr.get();
UnitData.Buffer = std::make_unique<DebugBufferVector>();
UnitData.Stream = std::make_unique<raw_svector_ostream>(*UnitData.Buffer);
raw_svector_ostream &OS = *UnitData.Stream.get();
// Returns true if AbbrevData is re-used, false otherwise.
auto hashAndAddAbbrev = [&](StringRef AbbrevData) -> bool {
llvm::SHA1 Hasher;
Hasher.update(AbbrevData);
std::array<uint8_t, 20> Hash = Hasher.final();
StringRef Key((const char *)Hash.data(), Hash.size());
auto Iter = AbbrevDataCache.find(Key);
if (Iter != AbbrevDataCache.end()) {
UnitsAbbrevData[&Unit] = Iter->second.get();
return true;
}
AbbrevDataCache[Key] = std::move(UnitDataPtr);
UnitsAbbrevData[&Unit] = &UnitData;
return false;
};
// Take a fast path if there are no patches to apply. Simply copy the original
// contents.
if (UnitPatches.empty() && AbbrevEntries.empty()) {
StringRef AbbrevSectionContents =
Unit.isDWOUnit() ? Unit.getContext().getDWARFObj().getAbbrevDWOSection()
: Unit.getContext().getDWARFObj().getAbbrevSection();
StringRef AbbrevContents;
const DWARFUnitIndex &CUIndex = Unit.getContext().getCUIndex();
if (!CUIndex.getRows().empty()) {
// Handle DWP section contribution.
const DWARFUnitIndex::Entry *DWOEntry =
CUIndex.getFromHash(*Unit.getDWOId());
if (!DWOEntry)
return;
const DWARFUnitIndex::Entry::SectionContribution *DWOContrubution =
DWOEntry->getContribution(DWARFSectionKind::DW_SECT_ABBREV);
AbbrevContents = AbbrevSectionContents.substr(
DWOContrubution->getOffset(), DWOContrubution->getLength());
} else if (!Unit.isDWOUnit()) {
const uint64_t StartOffset = Unit.getAbbreviationsOffset();
// We know where the unit's abbreviation set starts, but not where it ends
// as such data is not readily available. Hence, we have to build a sorted
// list of start addresses and find the next starting address to determine
// the set boundaries.
//
// FIXME: if we had a full access to DWARFDebugAbbrev::AbbrDeclSets
// we wouldn't have to build our own sorted list for the quick lookup.
if (AbbrevSetOffsets.empty()) {
for (const std::pair<const uint64_t, DWARFAbbreviationDeclarationSet>
&P : *Unit.getContext().getDebugAbbrev())
AbbrevSetOffsets.push_back(P.first);
sort(AbbrevSetOffsets);
}
auto It = upper_bound(AbbrevSetOffsets, StartOffset);
const uint64_t EndOffset =
It == AbbrevSetOffsets.end() ? AbbrevSectionContents.size() : *It;
AbbrevContents = AbbrevSectionContents.slice(StartOffset, EndOffset);
} else {
// For DWO unit outside of DWP, we expect the entire section to hold
// abbreviations for this unit only.
AbbrevContents = AbbrevSectionContents;
}
if (!hashAndAddAbbrev(AbbrevContents)) {
OS.reserveExtraSpace(AbbrevContents.size());
OS << AbbrevContents;
}
return;
}
for (auto I = Abbrevs->begin(), E = Abbrevs->end(); I != E; ++I) {
const DWARFAbbreviationDeclaration &Abbrev = *I;
auto Patch = UnitPatches.find(&Abbrev);
encodeULEB128(Abbrev.getCode(), OS);
encodeULEB128(Abbrev.getTag(), OS);
encodeULEB128(Abbrev.hasChildren(), OS);
for (const DWARFAbbreviationDeclaration::AttributeSpec &AttrSpec :
Abbrev.attributes()) {
if (Patch != UnitPatches.end()) {
bool Patched = false;
// Patches added later take a precedence over earlier ones.
for (const PatchInfo &PI : llvm::reverse(Patch->second)) {
if (PI.OldAttr != AttrSpec.Attr)
continue;
encodeULEB128(PI.NewAttr, OS);
encodeULEB128(PI.NewAttrForm, OS);
Patched = true;
break;
}
if (Patched)
continue;
}
encodeULEB128(AttrSpec.Attr, OS);
encodeULEB128(AttrSpec.Form, OS);
if (AttrSpec.isImplicitConst())
encodeSLEB128(AttrSpec.getImplicitConstValue(), OS);
}
const auto Entries = AbbrevEntries.find(&Abbrev);
// Adding new Abbrevs for inserted entries.
if (Entries != AbbrevEntries.end()) {
for (const AbbrevEntry &Entry : Entries->second) {
encodeULEB128(Entry.Attr, OS);
encodeULEB128(Entry.Form, OS);
}
}
encodeULEB128(0, OS);
encodeULEB128(0, OS);
}
encodeULEB128(0, OS);
hashAndAddAbbrev(OS.str());
}
std::unique_ptr<DebugBufferVector> DebugAbbrevWriter::finalize() {
// Used to create determinism for writing out abbrevs.
std::vector<AbbrevData *> Abbrevs;
if (DWOId) {
// We expect abbrev_offset to always be zero for DWO units as there
// should be one CU per DWO, and TUs should share the same abbreviation
// set with the CU.
// For DWP AbbreviationsOffset is an Abbrev contribution in the DWP file, so
// can be none zero. Thus we are skipping the check for DWP.
bool IsDWP = !Context.getCUIndex().getRows().empty();
if (!IsDWP) {
for (const std::unique_ptr<DWARFUnit> &Unit : Context.dwo_units()) {
if (Unit->getAbbreviationsOffset() != 0) {
errs() << "BOLT-ERROR: detected DWO unit with non-zero abbr_offset. "
"Unable to update debug info.\n";
exit(1);
}
}
}
DWARFUnit *Unit = Context.getDWOCompileUnitForHash(*DWOId);
// Issue abbreviations for the DWO CU only.
addUnitAbbreviations(*Unit);
AbbrevData *Abbrev = UnitsAbbrevData[Unit];
Abbrevs.push_back(Abbrev);
} else {
Abbrevs.reserve(Context.getNumCompileUnits() + Context.getNumTypeUnits());
std::unordered_set<AbbrevData *> ProcessedAbbrevs;
// Add abbreviations from compile and type non-DWO units.
for (const std::unique_ptr<DWARFUnit> &Unit : Context.normal_units()) {
addUnitAbbreviations(*Unit);
AbbrevData *Abbrev = UnitsAbbrevData[Unit.get()];
if (!ProcessedAbbrevs.insert(Abbrev).second)
continue;
Abbrevs.push_back(Abbrev);
}
}
DebugBufferVector ReturnBuffer;
// Pre-calculate the total size of abbrev section.
uint64_t Size = 0;
for (const AbbrevData *UnitData : Abbrevs)
Size += UnitData->Buffer->size();
ReturnBuffer.reserve(Size);
uint64_t Pos = 0;
for (AbbrevData *UnitData : Abbrevs) {
ReturnBuffer.append(*UnitData->Buffer);
UnitData->Offset = Pos;
Pos += UnitData->Buffer->size();
UnitData->Buffer.reset();
UnitData->Stream.reset();
}
return std::make_unique<DebugBufferVector>(ReturnBuffer);
}
static void emitDwarfSetLineAddrAbs(MCStreamer &OS,
MCDwarfLineTableParams Params,
int64_t LineDelta, uint64_t Address,
int PointerSize) {
// emit the sequence to set the address
OS.emitIntValue(dwarf::DW_LNS_extended_op, 1);
OS.emitULEB128IntValue(PointerSize + 1);
OS.emitIntValue(dwarf::DW_LNE_set_address, 1);
OS.emitIntValue(Address, PointerSize);
// emit the sequence for the LineDelta (from 1) and a zero address delta.
MCDwarfLineAddr::Emit(&OS, Params, LineDelta, 0);
}
static inline void emitBinaryDwarfLineTable(
MCStreamer *MCOS, MCDwarfLineTableParams Params,
const DWARFDebugLine::LineTable *Table,
const std::vector<DwarfLineTable::RowSequence> &InputSequences) {
if (InputSequences.empty())
return;
constexpr uint64_t InvalidAddress = UINT64_MAX;
unsigned FileNum = 1;
unsigned LastLine = 1;
unsigned Column = 0;
unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
unsigned Isa = 0;
unsigned Discriminator = 0;
uint64_t LastAddress = InvalidAddress;
uint64_t PrevEndOfSequence = InvalidAddress;
const MCAsmInfo *AsmInfo = MCOS->getContext().getAsmInfo();
auto emitEndOfSequence = [&](uint64_t Address) {
MCDwarfLineAddr::Emit(MCOS, Params, INT64_MAX, Address - LastAddress);
FileNum = 1;
LastLine = 1;
Column = 0;
Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
Isa = 0;
Discriminator = 0;
LastAddress = InvalidAddress;
};
for (const DwarfLineTable::RowSequence &Sequence : InputSequences) {
const uint64_t SequenceStart =
Table->Rows[Sequence.FirstIndex].Address.Address;
// Check if we need to mark the end of the sequence.
if (PrevEndOfSequence != InvalidAddress && LastAddress != InvalidAddress &&
PrevEndOfSequence != SequenceStart) {
emitEndOfSequence(PrevEndOfSequence);
}
for (uint32_t RowIndex = Sequence.FirstIndex;
RowIndex <= Sequence.LastIndex; ++RowIndex) {
const DWARFDebugLine::Row &Row = Table->Rows[RowIndex];
int64_t LineDelta = static_cast<int64_t>(Row.Line) - LastLine;
const uint64_t Address = Row.Address.Address;
if (FileNum != Row.File) {
FileNum = Row.File;
MCOS->emitInt8(dwarf::DW_LNS_set_file);
MCOS->emitULEB128IntValue(FileNum);
}
if (Column != Row.Column) {
Column = Row.Column;
MCOS->emitInt8(dwarf::DW_LNS_set_column);
MCOS->emitULEB128IntValue(Column);
}
if (Discriminator != Row.Discriminator &&
MCOS->getContext().getDwarfVersion() >= 4) {
Discriminator = Row.Discriminator;
unsigned Size = getULEB128Size(Discriminator);
MCOS->emitInt8(dwarf::DW_LNS_extended_op);
MCOS->emitULEB128IntValue(Size + 1);
MCOS->emitInt8(dwarf::DW_LNE_set_discriminator);
MCOS->emitULEB128IntValue(Discriminator);
}
if (Isa != Row.Isa) {
Isa = Row.Isa;
MCOS->emitInt8(dwarf::DW_LNS_set_isa);
MCOS->emitULEB128IntValue(Isa);
}
if (Row.IsStmt != Flags) {
Flags = Row.IsStmt;
MCOS->emitInt8(dwarf::DW_LNS_negate_stmt);
}
if (Row.BasicBlock)
MCOS->emitInt8(dwarf::DW_LNS_set_basic_block);
if (Row.PrologueEnd)
MCOS->emitInt8(dwarf::DW_LNS_set_prologue_end);
if (Row.EpilogueBegin)
MCOS->emitInt8(dwarf::DW_LNS_set_epilogue_begin);
// The end of the sequence is not normal in the middle of the input
// sequence, but could happen, e.g. for assembly code.
if (Row.EndSequence) {
emitEndOfSequence(Address);
} else {
if (LastAddress == InvalidAddress)
emitDwarfSetLineAddrAbs(*MCOS, Params, LineDelta, Address,
AsmInfo->getCodePointerSize());
else
MCDwarfLineAddr::Emit(MCOS, Params, LineDelta, Address - LastAddress);
LastAddress = Address;
LastLine = Row.Line;
}
Discriminator = 0;
}
PrevEndOfSequence = Sequence.EndAddress;
}
// Finish with the end of the sequence.
if (LastAddress != InvalidAddress)
emitEndOfSequence(PrevEndOfSequence);
}
// This function is similar to the one from MCDwarfLineTable, except it handles
// end-of-sequence entries differently by utilizing line entries with
// DWARF2_FLAG_END_SEQUENCE flag.
static inline void emitDwarfLineTable(
MCStreamer *MCOS, MCSection *Section,
const MCLineSection::MCDwarfLineEntryCollection &LineEntries) {
unsigned FileNum = 1;
unsigned LastLine = 1;
unsigned Column = 0;
unsigned Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
unsigned Isa = 0;
unsigned Discriminator = 0;
MCSymbol *LastLabel = nullptr;
const MCAsmInfo *AsmInfo = MCOS->getContext().getAsmInfo();
// Loop through each MCDwarfLineEntry and encode the dwarf line number table.
for (const MCDwarfLineEntry &LineEntry : LineEntries) {
if (LineEntry.getFlags() & DWARF2_FLAG_END_SEQUENCE) {
MCOS->emitDwarfAdvanceLineAddr(INT64_MAX, LastLabel, LineEntry.getLabel(),
AsmInfo->getCodePointerSize());
FileNum = 1;
LastLine = 1;
Column = 0;
Flags = DWARF2_LINE_DEFAULT_IS_STMT ? DWARF2_FLAG_IS_STMT : 0;
Isa = 0;
Discriminator = 0;
LastLabel = nullptr;
continue;
}
int64_t LineDelta = static_cast<int64_t>(LineEntry.getLine()) - LastLine;
if (FileNum != LineEntry.getFileNum()) {
FileNum = LineEntry.getFileNum();
MCOS->emitInt8(dwarf::DW_LNS_set_file);
MCOS->emitULEB128IntValue(FileNum);
}
if (Column != LineEntry.getColumn()) {
Column = LineEntry.getColumn();
MCOS->emitInt8(dwarf::DW_LNS_set_column);
MCOS->emitULEB128IntValue(Column);
}
if (Discriminator != LineEntry.getDiscriminator() &&
MCOS->getContext().getDwarfVersion() >= 2) {
Discriminator = LineEntry.getDiscriminator();
unsigned Size = getULEB128Size(Discriminator);
MCOS->emitInt8(dwarf::DW_LNS_extended_op);
MCOS->emitULEB128IntValue(Size + 1);
MCOS->emitInt8(dwarf::DW_LNE_set_discriminator);
MCOS->emitULEB128IntValue(Discriminator);
}
if (Isa != LineEntry.getIsa()) {
Isa = LineEntry.getIsa();
MCOS->emitInt8(dwarf::DW_LNS_set_isa);
MCOS->emitULEB128IntValue(Isa);
}
if ((LineEntry.getFlags() ^ Flags) & DWARF2_FLAG_IS_STMT) {
Flags = LineEntry.getFlags();
MCOS->emitInt8(dwarf::DW_LNS_negate_stmt);
}
if (LineEntry.getFlags() & DWARF2_FLAG_BASIC_BLOCK)
MCOS->emitInt8(dwarf::DW_LNS_set_basic_block);
if (LineEntry.getFlags() & DWARF2_FLAG_PROLOGUE_END)
MCOS->emitInt8(dwarf::DW_LNS_set_prologue_end);
if (LineEntry.getFlags() & DWARF2_FLAG_EPILOGUE_BEGIN)
MCOS->emitInt8(dwarf::DW_LNS_set_epilogue_begin);
MCSymbol *Label = LineEntry.getLabel();
// At this point we want to emit/create the sequence to encode the delta
// in line numbers and the increment of the address from the previous
// Label and the current Label.
MCOS->emitDwarfAdvanceLineAddr(LineDelta, LastLabel, Label,
AsmInfo->getCodePointerSize());
Discriminator = 0;
LastLine = LineEntry.getLine();
LastLabel = Label;
}
assert(LastLabel == nullptr && "end of sequence expected");
}
void DwarfLineTable::emitCU(MCStreamer *MCOS, MCDwarfLineTableParams Params,
std::optional<MCDwarfLineStr> &LineStr,
BinaryContext &BC) const {
if (!RawData.empty()) {
assert(MCLineSections.getMCLineEntries().empty() &&
InputSequences.empty() &&
"cannot combine raw data with new line entries");
MCOS->emitLabel(getLabel());
MCOS->emitBytes(RawData);
// Emit fake relocation for RuntimeDyld to always allocate the section.
//
// FIXME: remove this once RuntimeDyld stops skipping allocatable sections
// without relocations.
MCOS->emitRelocDirective(
*MCConstantExpr::create(0, *BC.Ctx), "BFD_RELOC_NONE",
MCSymbolRefExpr::create(getLabel(), *BC.Ctx), SMLoc(), *BC.STI);
return;
}
MCSymbol *LineEndSym = Header.Emit(MCOS, Params, LineStr).second;
// Put out the line tables.
for (const auto &LineSec : MCLineSections.getMCLineEntries())
emitDwarfLineTable(MCOS, LineSec.first, LineSec.second);
// Emit line tables for the original code.
emitBinaryDwarfLineTable(MCOS, Params, InputTable, InputSequences);
// This is the end of the section, so set the value of the symbol at the end
// of this section (that was used in a previous expression).
MCOS->emitLabel(LineEndSym);
}
// Helper function to parse .debug_line_str, and populate one we are using.
// For functions that we do not modify we output them as raw data.
// Re-constructing .debug_line_str so that offsets are correct for those
// debut line tables.
// Bonus is that when we output a final binary we can re-use .debug_line_str
// section. So we don't have to do the SHF_ALLOC trick we did with
// .debug_line.
static void parseAndPopulateDebugLineStr(BinarySection &LineStrSection,
MCDwarfLineStr &LineStr,
BinaryContext &BC,
MCStreamer &Streamer) {
DataExtractor StrData(LineStrSection.getContents(),
BC.DwCtx->isLittleEndian(), 0);
uint64_t Offset = 0;
while (StrData.isValidOffset(Offset)) {
Error Err = Error::success();
const char *CStr = StrData.getCStr(&Offset, &Err);
if (Err) {
errs() << "BOLT-ERROR: could not extract string from .debug_line_str";
continue;
}
LineStr.emitRef(&Streamer, CStr);
}
}
void DwarfLineTable::emit(BinaryContext &BC, MCStreamer &Streamer) {
MCAssembler &Assembler =
static_cast<MCObjectStreamer *>(&Streamer)->getAssembler();
MCDwarfLineTableParams Params = Assembler.getDWARFLinetableParams();
auto &LineTables = BC.getDwarfLineTables();
// Bail out early so we don't switch to the debug_line section needlessly and
// in doing so create an unnecessary (if empty) section.
if (LineTables.empty())
return;
// In a v5 non-split line table, put the strings in a separate section.
std::optional<MCDwarfLineStr> LineStr;
ErrorOr<BinarySection &> LineStrSection =
BC.getUniqueSectionByName(".debug_line_str");
// Some versions of GCC output DWARF5 .debug_info, but DWARF4 or lower
// .debug_line
if (LineStrSection) {
LineStr.emplace(*BC.Ctx);
parseAndPopulateDebugLineStr(*LineStrSection, *LineStr, BC, Streamer);
}
// Switch to the section where the table will be emitted into.
Streamer.switchSection(BC.MOFI->getDwarfLineSection());
const uint16_t DwarfVersion = BC.Ctx->getDwarfVersion();
// Handle the rest of the Compile Units.
for (auto &CUIDTablePair : LineTables) {
Streamer.getContext().setDwarfVersion(
CUIDTablePair.second.getDwarfVersion());
CUIDTablePair.second.emitCU(&Streamer, Params, LineStr, BC);
}
// Resetting DWARF version for rest of the flow.
BC.Ctx->setDwarfVersion(DwarfVersion);
// Still need to write the section out for the ExecutionEngine, and temp in
// memory object we are constructing.
if (LineStr) {
LineStr->emitSection(&Streamer);
SmallString<0> Data = LineStr->getFinalizedData();
BC.registerOrUpdateNoteSection(".debug_line_str", copyByteArray(Data.str()),
Data.size());
}
}
} // namespace bolt
} // namespace llvm