Google Git
Sign in
llvm / llvm-project / refs/tags/llvmorg-16.0.2 / . / bolt / lib / Rewrite / DWARFRewriter.cpp
blob: 5b8a28465fd7c9cd0554809a54075059ba775b82 [file] [log] [blame]
//===- bolt/Rewrite/DWARFRewriter.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 "bolt/Rewrite/DWARFRewriter.h"
#include "bolt/Core/BinaryContext.h"
#include "bolt/Core/BinaryFunction.h"
#include "bolt/Core/DebugData.h"
#include "bolt/Core/ParallelUtilities.h"
#include "bolt/Rewrite/RewriteInstance.h"
#include "bolt/Utils/Utils.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DWP/DWP.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmLayout.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/ThreadPool.h"
#include "llvm/Support/ToolOutputFile.h"
#include <algorithm>
#include <cstdint>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>
#undef DEBUG_TYPE
#define DEBUG_TYPE "bolt"
LLVM_ATTRIBUTE_UNUSED
static void printDie(const DWARFDie &DIE) {
DIDumpOptions DumpOpts;
DumpOpts.ShowForm = true;
DumpOpts.Verbose = true;
DumpOpts.ChildRecurseDepth = 0;
DumpOpts.ShowChildren = false;
DIE.dump(dbgs(), 0, DumpOpts);
}
namespace llvm {
namespace bolt {
/// Finds attributes FormValue and Offset.
///
/// \param DIE die to look up in.
/// \param Attrs finds the first attribute that matches and extracts it.
/// \return an optional AttrInfo with DWARFFormValue and Offset.
std::optional<AttrInfo> findAttributeInfo(const DWARFDie DIE,
std::vector<dwarf::Attribute> Attrs) {
for (dwarf::Attribute &Attr : Attrs)
if (std::optional<AttrInfo> Info = findAttributeInfo(DIE, Attr))
return Info;
return std::nullopt;
}
} // namespace bolt
} // namespace llvm
using namespace llvm;
using namespace llvm::support::endian;
using namespace object;
using namespace bolt;
namespace opts {
extern cl::OptionCategory BoltCategory;
extern cl::opt<unsigned> Verbosity;
extern cl::opt<std::string> OutputFilename;
static cl::opt<bool> KeepARanges(
"keep-aranges",
cl::desc(
"keep or generate .debug_aranges section if .gdb_index is written"),
cl::Hidden, cl::cat(BoltCategory));
static cl::opt<bool>
DeterministicDebugInfo("deterministic-debuginfo",
cl::desc("disables parallel execution of tasks that may produce "
"nondeterministic debug info"),
cl::init(true),
cl::cat(BoltCategory));
static cl::opt<std::string> DwarfOutputPath(
"dwarf-output-path",
cl::desc("Path to where .dwo files or dwp file will be written out to."),
cl::init(""), cl::cat(BoltCategory));
static cl::opt<bool>
WriteDWP("write-dwp",
cl::desc("output a single dwarf package file (dwp) instead of "
"multiple non-relocatable dwarf object files (dwo)."),
cl::init(false), cl::cat(BoltCategory));
static cl::opt<bool>
DebugSkeletonCu("debug-skeleton-cu",
cl::desc("prints out offsetrs for abbrev and debu_info of "
"Skeleton CUs that get patched."),
cl::ZeroOrMore, cl::Hidden, cl::init(false),
cl::cat(BoltCategory));
} // namespace opts
/// Returns DWO Name to be used. Handles case where user specifies output DWO
/// directory, and there are duplicate names. Assumes DWO ID is unique.
static std::string
getDWOName(llvm::DWARFUnit &CU,
std::unordered_map<std::string, uint32_t> *NameToIndexMap,
std::unordered_map<uint64_t, std::string> &DWOIdToName) {
std::optional<uint64_t> DWOId = CU.getDWOId();
assert(DWOId && "DWO ID not found.");
(void)DWOId;
auto NameIter = DWOIdToName.find(*DWOId);
if (NameIter != DWOIdToName.end())
return NameIter->second;
std::string DWOName = dwarf::toString(
CU.getUnitDIE().find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}),
"");
assert(!DWOName.empty() &&
"DW_AT_dwo_name/DW_AT_GNU_dwo_name does not exists.");
if (NameToIndexMap && !opts::DwarfOutputPath.empty()) {
auto Iter = NameToIndexMap->find(DWOName);
if (Iter == NameToIndexMap->end())
Iter = NameToIndexMap->insert({DWOName, 0}).first;
DWOName.append(std::to_string(Iter->second));
++Iter->second;
}
DWOName.append(".dwo");
DWOIdToName[*DWOId] = DWOName;
return DWOName;
}
void DWARFRewriter::addStringHelper(DebugInfoBinaryPatcher &DebugInfoPatcher,
const DWARFUnit &Unit,
const AttrInfo &AttrInfoVal,
StringRef Str) {
uint32_t NewOffset = StrWriter->addString(Str);
if (Unit.getVersion() == 5) {
StrOffstsWriter->updateAddressMap(AttrInfoVal.V.getRawUValue(), NewOffset);
return;
}
DebugInfoPatcher.addLE32Patch(AttrInfoVal.Offset, NewOffset,
AttrInfoVal.Size);
}
void DWARFRewriter::updateDebugInfo() {
ErrorOr<BinarySection &> DebugInfo = BC.getUniqueSectionByName(".debug_info");
if (!DebugInfo)
return;
auto *DebugInfoPatcher =
static_cast<DebugInfoBinaryPatcher *>(DebugInfo->getPatcher());
ARangesSectionWriter = std::make_unique<DebugARangesSectionWriter>();
StrWriter = std::make_unique<DebugStrWriter>(BC);
StrOffstsWriter = std::make_unique<DebugStrOffsetsWriter>();
AbbrevWriter = std::make_unique<DebugAbbrevWriter>(*BC.DwCtx);
if (!opts::DeterministicDebugInfo) {
opts::DeterministicDebugInfo = true;
errs() << "BOLT-WARNING: --deterministic-debuginfo is being deprecated\n";
}
if (BC.isDWARF5Used()) {
AddrWriter = std::make_unique<DebugAddrWriterDwarf5>(&BC);
RangeListsSectionWriter = std::make_unique<DebugRangeListsSectionWriter>();
DebugRangeListsSectionWriter::setAddressWriter(AddrWriter.get());
} else {
AddrWriter = std::make_unique<DebugAddrWriter>(&BC);
}
if (BC.isDWARFLegacyUsed())
LegacyRangesSectionWriter = std::make_unique<DebugRangesSectionWriter>();
DebugLoclistWriter::setAddressWriter(AddrWriter.get());
size_t CUIndex = 0;
for (std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
const uint16_t DwarfVersion = CU->getVersion();
if (DwarfVersion >= 5) {
LocListWritersByCU[CUIndex] =
std::make_unique<DebugLoclistWriter>(*CU.get(), DwarfVersion, false);
if (std::optional<uint64_t> DWOId = CU->getDWOId()) {
assert(LocListWritersByCU.count(*DWOId) == 0 &&
"RangeLists writer for DWO unit already exists.");
auto RangeListsSectionWriter =
std::make_unique<DebugRangeListsSectionWriter>();
RangeListsSectionWriter->initSection(*CU.get());
RangeListsWritersByCU[*DWOId] = std::move(RangeListsSectionWriter);
}
} else {
LocListWritersByCU[CUIndex] = std::make_unique<DebugLocWriter>();
}
if (std::optional<uint64_t> DWOId = CU->getDWOId()) {
assert(LocListWritersByCU.count(*DWOId) == 0 &&
"LocList writer for DWO unit already exists.");
// Work around some bug in llvm-15. If I pass in directly lld reports
// undefined symbol.
LocListWritersByCU[*DWOId] =
std::make_unique<DebugLoclistWriter>(*CU.get(), DwarfVersion, true);
}
++CUIndex;
}
// Unordered maps to handle name collision if output DWO directory is
// specified.
std::unordered_map<std::string, uint32_t> NameToIndexMap;
std::unordered_map<uint64_t, std::string> DWOIdToName;
std::mutex AccessMutex;
auto updateDWONameCompDir = [&](DWARFUnit &Unit) -> void {
const DWARFDie &DIE = Unit.getUnitDIE();
std::optional<AttrInfo> AttrInfoVal = findAttributeInfo(
DIE, {dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name});
(void)AttrInfoVal;
assert(AttrInfoVal && "Skeleton CU doesn't have dwo_name.");
std::string ObjectName;
{
std::lock_guard<std::mutex> Lock(AccessMutex);
ObjectName = getDWOName(Unit, &NameToIndexMap, DWOIdToName);
}
addStringHelper(*DebugInfoPatcher, Unit, *AttrInfoVal, ObjectName.c_str());
AttrInfoVal = findAttributeInfo(DIE, dwarf::DW_AT_comp_dir);
(void)AttrInfoVal;
assert(AttrInfoVal && "DW_AT_comp_dir is not in Skeleton CU.");
if (!opts::DwarfOutputPath.empty()) {
addStringHelper(*DebugInfoPatcher, Unit, *AttrInfoVal,
opts::DwarfOutputPath.c_str());
}
};
auto processUnitDIE = [&](size_t CUIndex, DWARFUnit *Unit) {
// Check if the unit is a skeleton and we need special updates for it and
// its matching split/DWO CU.
std::optional<DWARFUnit *> SplitCU;
std::optional<uint64_t> RangesBase;
std::optional<uint64_t> DWOId = Unit->getDWOId();
StrOffstsWriter->initialize(Unit->getStringOffsetSection(),
Unit->getStringOffsetsTableContribution());
if (DWOId)
SplitCU = BC.getDWOCU(*DWOId);
DebugLocWriter *DebugLocWriter = nullptr;
DebugRangesSectionWriter *RangesSectionWriter =
Unit->getVersion() >= 5 ? RangeListsSectionWriter.get()
: LegacyRangesSectionWriter.get();
// Skipping CUs that failed to load.
if (SplitCU) {
updateDWONameCompDir(*Unit);
DebugInfoBinaryPatcher *DwoDebugInfoPatcher =
llvm::cast<DebugInfoBinaryPatcher>(
getBinaryDWODebugInfoPatcher(*DWOId));
DWARFContext *DWOCtx = BC.getDWOContext();
// Setting this CU offset with DWP to normalize DIE offsets to uint32_t
if (DWOCtx && !DWOCtx->getCUIndex().getRows().empty())
DwoDebugInfoPatcher->setDWPOffset((*SplitCU)->getOffset());
{
std::lock_guard<std::mutex> Lock(AccessMutex);
DebugLocWriter = LocListWritersByCU[*DWOId].get();
}
DebugRangesSectionWriter *TempRangesSectionWriter = RangesSectionWriter;
if (Unit->getVersion() >= 5) {
TempRangesSectionWriter = RangeListsWritersByCU[*DWOId].get();
} else {
RangesBase = RangesSectionWriter->getSectionOffset();
// For DWARF5 there is now .debug_rnglists.dwo, so don't need to
// update rnglists base.
DwoDebugInfoPatcher->setRangeBase(*RangesBase);
}
DwoDebugInfoPatcher->addUnitBaseOffsetLabel((*SplitCU)->getOffset());
DebugAbbrevWriter *DWOAbbrevWriter =
createBinaryDWOAbbrevWriter((*SplitCU)->getContext(), *DWOId);
updateUnitDebugInfo(*(*SplitCU), *DwoDebugInfoPatcher, *DWOAbbrevWriter,
*DebugLocWriter, *TempRangesSectionWriter);
DebugLocWriter->finalize(*DwoDebugInfoPatcher, *DWOAbbrevWriter);
DwoDebugInfoPatcher->clearDestinationLabels();
if (!DwoDebugInfoPatcher->getWasRangBasedUsed())
RangesBase = std::nullopt;
if (Unit->getVersion() >= 5)
TempRangesSectionWriter->finalizeSection();
}
{
std::lock_guard<std::mutex> Lock(AccessMutex);
auto LocListWriterIter = LocListWritersByCU.find(CUIndex);
if (LocListWriterIter != LocListWritersByCU.end())
DebugLocWriter = LocListWriterIter->second.get();
}
if (Unit->getVersion() >= 5) {
RangesBase = RangesSectionWriter->getSectionOffset() +
getDWARF5RngListLocListHeaderSize();
RangesSectionWriter->initSection(*Unit);
StrOffstsWriter->finalizeSection(*Unit);
}
DebugInfoPatcher->addUnitBaseOffsetLabel(Unit->getOffset());
updateUnitDebugInfo(*Unit, *DebugInfoPatcher, *AbbrevWriter,
*DebugLocWriter, *RangesSectionWriter, RangesBase);
DebugLocWriter->finalize(*DebugInfoPatcher, *AbbrevWriter);
if (Unit->getVersion() >= 5)
RangesSectionWriter->finalizeSection();
};
CUIndex = 0;
if (opts::NoThreads || opts::DeterministicDebugInfo) {
for (std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units())
processUnitDIE(CUIndex++, CU.get());
} else {
// Update unit debug info in parallel
ThreadPool &ThreadPool = ParallelUtilities::getThreadPool();
for (std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
ThreadPool.async(processUnitDIE, CUIndex, CU.get());
CUIndex++;
}
ThreadPool.wait();
}
DebugInfoPatcher->clearDestinationLabels();
CUOffsetMap OffsetMap = finalizeDebugSections(*DebugInfoPatcher);
if (opts::WriteDWP)
writeDWP(DWOIdToName);
else
writeDWOFiles(DWOIdToName);
updateGdbIndexSection(OffsetMap);
}
void DWARFRewriter::updateUnitDebugInfo(
DWARFUnit &Unit, DebugInfoBinaryPatcher &DebugInfoPatcher,
DebugAbbrevWriter &AbbrevWriter, DebugLocWriter &DebugLocWriter,
DebugRangesSectionWriter &RangesSectionWriter,
std::optional<uint64_t> RangesBase) {
// Cache debug ranges so that the offset for identical ranges could be reused.
std::map<DebugAddressRangesVector, uint64_t> CachedRanges;
uint64_t DIEOffset = Unit.getOffset() + Unit.getHeaderSize();
uint64_t NextCUOffset = Unit.getNextUnitOffset();
DWARFDebugInfoEntry Die;
DWARFDataExtractor DebugInfoData = Unit.getDebugInfoExtractor();
uint32_t Depth = 0;
bool IsDWP = false;
if (DWARFContext *DWOCtx = BC.getDWOContext())
IsDWP = !DWOCtx->getCUIndex().getRows().empty();
while (
DIEOffset < NextCUOffset &&
Die.extractFast(Unit, &DIEOffset, DebugInfoData, NextCUOffset, Depth)) {
if (const DWARFAbbreviationDeclaration *AbbrDecl =
Die.getAbbreviationDeclarationPtr()) {
if (AbbrDecl->hasChildren())
++Depth;
} else {
// NULL entry.
if (Depth > 0)
--Depth;
if (Depth == 0)
break;
}
DWARFDie DIE(&Unit, &Die);
switch (DIE.getTag()) {
case dwarf::DW_TAG_compile_unit:
case dwarf::DW_TAG_skeleton_unit: {
// For dwarf5 section 3.1.3
// The following attributes are not part of a split full compilation unit
// entry but instead are inherited (if present) from the corresponding
// skeleton compilation unit: DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges,
// DW_AT_stmt_list, DW_AT_comp_dir, DW_AT_str_offsets_base,
// DW_AT_addr_base and DW_AT_rnglists_base.
if (Unit.getVersion() == 5 && Unit.isDWOUnit())
continue;
auto ModuleRangesOrError = DIE.getAddressRanges();
if (!ModuleRangesOrError) {
consumeError(ModuleRangesOrError.takeError());
break;
}
DWARFAddressRangesVector &ModuleRanges = *ModuleRangesOrError;
DebugAddressRangesVector OutputRanges =
BC.translateModuleAddressRanges(ModuleRanges);
const uint64_t RangesSectionOffset =
RangesSectionWriter.addRanges(OutputRanges);
if (!Unit.isDWOUnit())
ARangesSectionWriter->addCURanges(Unit.getOffset(),
std::move(OutputRanges));
updateDWARFObjectAddressRanges(DIE, RangesSectionOffset, DebugInfoPatcher,
AbbrevWriter, 0, RangesBase);
break;
}
case dwarf::DW_TAG_subprogram: {
// Get function address either from ranges or [LowPC, HighPC) pair.
uint64_t Address;
uint64_t SectionIndex, HighPC;
if (!DIE.getLowAndHighPC(Address, HighPC, SectionIndex)) {
Expected<DWARFAddressRangesVector> RangesOrError =
DIE.getAddressRanges();
if (!RangesOrError) {
consumeError(RangesOrError.takeError());
break;
}
DWARFAddressRangesVector Ranges = *RangesOrError;
// Not a function definition.
if (Ranges.empty())
break;
Address = Ranges.front().LowPC;
}
// Clear cached ranges as the new function will have its own set.
CachedRanges.clear();
DebugAddressRangesVector FunctionRanges;
if (const BinaryFunction *Function =
BC.getBinaryFunctionAtAddress(Address))
FunctionRanges = Function->getOutputAddressRanges();
if (FunctionRanges.empty())
FunctionRanges.push_back({0, 0});
updateDWARFObjectAddressRanges(
DIE, RangesSectionWriter.addRanges(FunctionRanges), DebugInfoPatcher,
AbbrevWriter, 0);
break;
}
case dwarf::DW_TAG_lexical_block:
case dwarf::DW_TAG_inlined_subroutine:
case dwarf::DW_TAG_try_block:
case dwarf::DW_TAG_catch_block: {
uint64_t RangesSectionOffset = RangesSectionWriter.getEmptyRangesOffset();
Expected<DWARFAddressRangesVector> RangesOrError = DIE.getAddressRanges();
const BinaryFunction *Function =
RangesOrError && !RangesOrError->empty()
? BC.getBinaryFunctionContainingAddress(
RangesOrError->front().LowPC)
: nullptr;
bool ErrorState = false;
std::optional<uint64_t> NewLowPC;
if (Function) {
DebugAddressRangesVector OutputRanges =
Function->translateInputToOutputRanges(*RangesOrError);
LLVM_DEBUG(if (OutputRanges.empty() != RangesOrError->empty()) {
dbgs() << "BOLT-DEBUG: problem with DIE at 0x"
<< Twine::utohexstr(DIE.getOffset()) << " in CU at 0x"
<< Twine::utohexstr(Unit.getOffset()) << '\n';
});
if (!OutputRanges.empty())
NewLowPC = OutputRanges.front().LowPC;
RangesSectionOffset = RangesSectionWriter.addRanges(
std::move(OutputRanges), CachedRanges);
} else if (!RangesOrError) {
ErrorState = true;
consumeError(RangesOrError.takeError());
}
uint64_t LowPCToUse = 0;
if (!ErrorState && RangesOrError.get().size() == 1 &&
RangesOrError.get().begin()->LowPC ==
RangesOrError.get().begin()->HighPC) {
if (NewLowPC)
LowPCToUse = NewLowPC.value();
else
LowPCToUse = RangesOrError.get().begin()->LowPC;
}
updateDWARFObjectAddressRanges(DIE, RangesSectionOffset, DebugInfoPatcher,
AbbrevWriter, LowPCToUse);
break;
}
case dwarf::DW_TAG_call_site: {
auto patchPC = [&](AttrInfo &AttrVal, StringRef Entry) -> void {
std::optional<uint64_t> Address = AttrVal.V.getAsAddress();
const BinaryFunction *Function =
BC.getBinaryFunctionContainingAddress(*Address);
uint64_t UpdatedAddress = *Address;
if (Function)
UpdatedAddress =
Function->translateInputToOutputAddress(UpdatedAddress);
if (AttrVal.V.getForm() == dwarf::DW_FORM_addrx) {
const uint32_t Index =
AddrWriter->getIndexFromAddress(UpdatedAddress, Unit);
DebugInfoPatcher.addUDataPatch(AttrVal.Offset, Index, AttrVal.Size);
} else if (AttrVal.V.getForm() == dwarf::DW_FORM_addr) {
DebugInfoPatcher.addLE32Patch(AttrVal.Offset, UpdatedAddress);
} else {
errs() << "BOLT-ERROR: unsupported form for " << Entry << "\n";
}
};
if (std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_call_pc))
patchPC(*AttrVal, "DW_AT_call_pc");
if (std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_call_return_pc))
patchPC(*AttrVal, "DW_AT_call_return_pc");
break;
}
default: {
// Handle any tag that can have DW_AT_location attribute.
DWARFFormValue Value;
uint64_t AttrOffset;
if (std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_location)) {
AttrOffset = AttrVal->Offset;
Value = AttrVal->V;
if (Value.isFormClass(DWARFFormValue::FC_Constant) ||
Value.isFormClass(DWARFFormValue::FC_SectionOffset)) {
uint64_t Offset = Value.isFormClass(DWARFFormValue::FC_Constant)
? Value.getAsUnsignedConstant().value()
: Value.getAsSectionOffset().value();
DebugLocationsVector InputLL;
std::optional<object::SectionedAddress> SectionAddress =
Unit.getBaseAddress();
uint64_t BaseAddress = 0;
if (SectionAddress)
BaseAddress = SectionAddress->Address;
if (Unit.getVersion() >= 5 &&
AttrVal->V.getForm() == dwarf::DW_FORM_loclistx) {
std::optional<uint64_t> LocOffset = Unit.getLoclistOffset(Offset);
assert(LocOffset && "Location Offset is invalid.");
Offset = *LocOffset;
}
Error E = Unit.getLocationTable().visitLocationList(
&Offset, [&](const DWARFLocationEntry &Entry) {
switch (Entry.Kind) {
default:
llvm_unreachable("Unsupported DWARFLocationEntry Kind.");
case dwarf::DW_LLE_end_of_list:
return false;
case dwarf::DW_LLE_base_address: {
assert(Entry.SectionIndex == SectionedAddress::UndefSection &&
"absolute address expected");
BaseAddress = Entry.Value0;
break;
}
case dwarf::DW_LLE_offset_pair:
assert(
(Entry.SectionIndex == SectionedAddress::UndefSection &&
(!Unit.isDWOUnit() || Unit.getVersion() == 5)) &&
"absolute address expected");
InputLL.emplace_back(DebugLocationEntry{
BaseAddress + Entry.Value0, BaseAddress + Entry.Value1,
Entry.Loc});
break;
case dwarf::DW_LLE_start_length:
InputLL.emplace_back(DebugLocationEntry{
Entry.Value0, Entry.Value0 + Entry.Value1, Entry.Loc});
break;
case dwarf::DW_LLE_base_addressx: {
std::optional<object::SectionedAddress> EntryAddress =
Unit.getAddrOffsetSectionItem(Entry.Value0);
assert(EntryAddress && "base Address not found.");
BaseAddress = EntryAddress->Address;
break;
}
case dwarf::DW_LLE_startx_length: {
std::optional<object::SectionedAddress> EntryAddress =
Unit.getAddrOffsetSectionItem(Entry.Value0);
assert(EntryAddress && "Address does not exist.");
InputLL.emplace_back(DebugLocationEntry{
EntryAddress->Address,
EntryAddress->Address + Entry.Value1, Entry.Loc});
break;
}
case dwarf::DW_LLE_startx_endx: {
std::optional<object::SectionedAddress> StartAddress =
Unit.getAddrOffsetSectionItem(Entry.Value0);
assert(StartAddress && "Start Address does not exist.");
std::optional<object::SectionedAddress> EndAddress =
Unit.getAddrOffsetSectionItem(Entry.Value1);
assert(EndAddress && "Start Address does not exist.");
InputLL.emplace_back(DebugLocationEntry{
StartAddress->Address, EndAddress->Address, Entry.Loc});
break;
}
}
return true;
});
if (E || InputLL.empty()) {
consumeError(std::move(E));
errs() << "BOLT-WARNING: empty location list detected at 0x"
<< Twine::utohexstr(Offset) << " for DIE at 0x"
<< Twine::utohexstr(DIE.getOffset()) << " in CU at 0x"
<< Twine::utohexstr(Unit.getOffset()) << '\n';
} else {
const uint64_t Address = InputLL.front().LowPC;
DebugLocationsVector OutputLL;
if (const BinaryFunction *Function =
BC.getBinaryFunctionContainingAddress(Address)) {
OutputLL = Function->translateInputToOutputLocationList(InputLL);
LLVM_DEBUG(if (OutputLL.empty()) {
dbgs() << "BOLT-DEBUG: location list translated to an empty "
"one at 0x"
<< Twine::utohexstr(DIE.getOffset()) << " in CU at 0x"
<< Twine::utohexstr(Unit.getOffset()) << '\n';
});
} else {
// It's possible for a subprogram to be removed and to have
// address of 0. Adding this entry to output to preserve debug
// information.
OutputLL = InputLL;
}
DebugLocWriter.addList(*AttrVal, OutputLL, DebugInfoPatcher,
AbbrevWriter);
}
} else {
assert((Value.isFormClass(DWARFFormValue::FC_Exprloc) ||
Value.isFormClass(DWARFFormValue::FC_Block)) &&
"unexpected DW_AT_location form");
if (Unit.isDWOUnit() || Unit.getVersion() >= 5) {
ArrayRef<uint8_t> Expr = *Value.getAsBlock();
DataExtractor Data(
StringRef((const char *)Expr.data(), Expr.size()),
Unit.getContext().isLittleEndian(), 0);
DWARFExpression LocExpr(Data, Unit.getAddressByteSize(),
Unit.getFormParams().Format);
uint32_t PrevEndOffset = 0;
uint32_t CurrEndOffset = 0;
constexpr uint32_t SizeOfOP = 1;
constexpr uint32_t SizeOfSizeField = 1;
int32_t SizeDiff = 0;
// Encoding [size of expression] [opcode] [value] [opcode] [value]
for (auto &Expr : LocExpr) {
PrevEndOffset = CurrEndOffset;
CurrEndOffset = Expr.getEndOffset();
if (!(Expr.getCode() == dwarf::DW_OP_GNU_addr_index ||
Expr.getCode() == dwarf::DW_OP_addrx))
continue;
const uint64_t Index = Expr.getRawOperand(0);
std::optional<object::SectionedAddress> EntryAddress =
Unit.getAddrOffsetSectionItem(Index);
assert(EntryAddress && "Address is not found.");
assert(Index <= std::numeric_limits<uint32_t>::max() &&
"Invalid Operand Index.");
if (Expr.getCode() == dwarf::DW_OP_addrx) {
const uint32_t EncodingSize = CurrEndOffset - PrevEndOffset - 1;
const uint32_t Index = AddrWriter->getIndexFromAddress(
EntryAddress->Address, Unit);
// Encoding new size.
SmallString<8> Tmp;
raw_svector_ostream OSE(Tmp);
encodeULEB128(Index, OSE);
SizeDiff += Tmp.size() - EncodingSize;
DebugInfoPatcher.addUDataPatch(AttrOffset + PrevEndOffset +
SizeOfOP + SizeOfSizeField,
Index, EncodingSize);
} else {
// TODO: Re-do this as DWARF5.
AddrWriter->addIndexAddress(EntryAddress->Address,
static_cast<uint32_t>(Index), Unit);
}
}
// Update the size of the experssion.
if (SizeDiff)
DebugInfoPatcher.addUDataPatch(AttrOffset,
SizeDiff + CurrEndOffset, 1);
}
}
} else if (std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_low_pc)) {
AttrOffset = AttrVal->Offset;
Value = AttrVal->V;
const std::optional<uint64_t> Result = Value.getAsAddress();
if (Result) {
const uint64_t Address = *Result;
uint64_t NewAddress = 0;
if (const BinaryFunction *Function =
BC.getBinaryFunctionContainingAddress(Address)) {
NewAddress = Function->translateInputToOutputAddress(Address);
LLVM_DEBUG(dbgs()
<< "BOLT-DEBUG: Fixing low_pc 0x"
<< Twine::utohexstr(Address) << " for DIE with tag "
<< DIE.getTag() << " to 0x"
<< Twine::utohexstr(NewAddress) << '\n');
}
dwarf::Form Form = Value.getForm();
assert(Form != dwarf::DW_FORM_LLVM_addrx_offset &&
"DW_FORM_LLVM_addrx_offset is not supported");
std::lock_guard<std::mutex> Lock(DebugInfoPatcherMutex);
if (Form == dwarf::DW_FORM_GNU_addr_index) {
const uint64_t Index = Value.getRawUValue();
// If there is no new address, storing old address.
// Re-using Index to make implementation easier.
// DW_FORM_GNU_addr_index is variable lenght encoding
// so we either have to create indices of same sizes, or use same
// index.
// TODO: We can now re-write .debug_info. This can be simplified to
// just getting a new index and creating a patch.
AddrWriter->addIndexAddress(NewAddress ? NewAddress : Address,
Index, Unit);
} else if (Form == dwarf::DW_FORM_addrx) {
const uint32_t Index = AddrWriter->getIndexFromAddress(
NewAddress ? NewAddress : Address, Unit);
DebugInfoPatcher.addUDataPatch(AttrOffset, Index, AttrVal->Size);
} else {
DebugInfoPatcher.addLE64Patch(AttrOffset, NewAddress);
}
} else if (opts::Verbosity >= 1) {
errs() << "BOLT-WARNING: unexpected form value for attribute at 0x"
<< Twine::utohexstr(AttrOffset);
}
} else if (IsDWP && Unit.isDWOUnit()) {
// Not a common path so don't want to search all DIEs all the time.
std::optional<AttrInfo> SignatureAttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_signature);
if (!SignatureAttrVal)
continue;
// If input is DWP file we need to keep track of which TU came from each
// CU, so we can write it out correctly.
if (std::optional<uint64_t> Val =
SignatureAttrVal->V.getAsReferenceUVal())
TypeSignaturesPerCU[*DIE.getDwarfUnit()->getDWOId()].insert(*Val);
else {
errs() << "BOT-ERROR: DW_AT_signature form is not supported.\n";
exit(1);
}
}
}
}
// Handling references.
assert(DIE.isValid() && "Invalid DIE.");
const DWARFAbbreviationDeclaration *AbbrevDecl =
DIE.getAbbreviationDeclarationPtr();
if (!AbbrevDecl)
continue;
uint32_t Index = 0;
for (const DWARFAbbreviationDeclaration::AttributeSpec &Decl :
AbbrevDecl->attributes()) {
switch (Decl.Form) {
default:
break;
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:
case dwarf::DW_FORM_ref_addr: {
std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, AbbrevDecl, Index);
uint32_t DestinationAddress =
AttrVal->V.getRawUValue() +
(Decl.Form == dwarf::DW_FORM_ref_addr ? 0 : Unit.getOffset());
DebugInfoPatcher.addReferenceToPatch(
AttrVal->Offset, DestinationAddress, AttrVal->Size, Decl.Form);
// We can have only one reference, and it can be backward one.
DebugInfoPatcher.addDestinationReferenceLabel(DestinationAddress);
break;
}
}
++Index;
}
}
if (DIEOffset > NextCUOffset)
errs() << "BOLT-WARNING: corrupt DWARF detected at 0x"
<< Twine::utohexstr(Unit.getOffset()) << '\n';
}
void DWARFRewriter::updateDWARFObjectAddressRanges(
const DWARFDie DIE, uint64_t DebugRangesOffset,
SimpleBinaryPatcher &DebugInfoPatcher, DebugAbbrevWriter &AbbrevWriter,
uint64_t LowPCToUse, std::optional<uint64_t> RangesBase) {
// Some objects don't have an associated DIE and cannot be updated (such as
// compiler-generated functions).
if (!DIE)
return;
const DWARFAbbreviationDeclaration *AbbreviationDecl =
DIE.getAbbreviationDeclarationPtr();
if (!AbbreviationDecl) {
if (opts::Verbosity >= 1)
errs() << "BOLT-WARNING: object's DIE doesn't have an abbreviation: "
<< "skipping update. DIE at offset 0x"
<< Twine::utohexstr(DIE.getOffset()) << '\n';
return;
}
if (RangesBase) {
// If DW_AT_GNU_ranges_base is present, update it. No further modifications
// are needed for ranges base.
std::optional<AttrInfo> RangesBaseAttrInfo =
findAttributeInfo(DIE, dwarf::DW_AT_GNU_ranges_base);
if (!RangesBaseAttrInfo)
RangesBaseAttrInfo = findAttributeInfo(DIE, dwarf::DW_AT_rnglists_base);
if (RangesBaseAttrInfo) {
DebugInfoPatcher.addLE32Patch(RangesBaseAttrInfo->Offset,
static_cast<uint32_t>(*RangesBase),
RangesBaseAttrInfo->Size);
RangesBase = std::nullopt;
}
}
std::optional<AttrInfo> LowPCAttrInfo =
findAttributeInfo(DIE, dwarf::DW_AT_low_pc);
if (std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_ranges)) {
// Case 1: The object was already non-contiguous and had DW_AT_ranges.
// In this case we simply need to update the value of DW_AT_ranges
// and introduce DW_AT_GNU_ranges_base if required.
std::lock_guard<std::mutex> Lock(DebugInfoPatcherMutex);
// For DWARF5 converting all of DW_AT_ranges into DW_FORM_rnglistx
bool Converted = false;
if (DIE.getDwarfUnit()->getVersion() >= 5 &&
AttrVal->V.getForm() == dwarf::DW_FORM_sec_offset) {
AbbrevWriter.addAttributePatch(*DIE.getDwarfUnit(), AbbreviationDecl,
dwarf::DW_AT_ranges, dwarf::DW_AT_ranges,
dwarf::DW_FORM_rnglistx);
Converted = true;
}
if (Converted || AttrVal->V.getForm() == dwarf::DW_FORM_rnglistx)
DebugInfoPatcher.addUDataPatch(AttrVal->Offset, DebugRangesOffset,
AttrVal->Size);
else
DebugInfoPatcher.addLE32Patch(
AttrVal->Offset, DebugRangesOffset - DebugInfoPatcher.getRangeBase(),
AttrVal->Size);
if (!RangesBase) {
if (LowPCAttrInfo &&
LowPCAttrInfo->V.getForm() != dwarf::DW_FORM_GNU_addr_index &&
LowPCAttrInfo->V.getForm() != dwarf::DW_FORM_addrx)
DebugInfoPatcher.addLE64Patch(LowPCAttrInfo->Offset, LowPCToUse);
return;
}
if (DIE.getOffset() != DIE.getDwarfUnit()->getUnitDIE().getOffset())
return;
// If we are at this point we are in the CU/Skeleton CU, and
// DW_AT_GNU_ranges_base or DW_AT_rnglists_base doesn't exist.
if (DIE.getDwarfUnit()->getVersion() >= 5) {
AbbrevWriter.addAttribute(*DIE.getDwarfUnit(), AbbreviationDecl,
dwarf::DW_AT_rnglists_base,
dwarf::DW_FORM_sec_offset);
} else {
AbbrevWriter.addAttribute(*DIE.getDwarfUnit(), AbbreviationDecl,
dwarf::DW_AT_GNU_ranges_base,
dwarf::DW_FORM_sec_offset);
}
reinterpret_cast<DebugInfoBinaryPatcher &>(DebugInfoPatcher)
.insertNewEntry(DIE, *RangesBase);
return;
}
// Case 2: The object has both DW_AT_low_pc and DW_AT_high_pc emitted back
// to back. Replace with new attributes and patch the DIE.
std::optional<AttrInfo> HighPCAttrInfo =
findAttributeInfo(DIE, dwarf::DW_AT_high_pc);
if (LowPCAttrInfo && HighPCAttrInfo) {
convertToRangesPatchAbbrev(*DIE.getDwarfUnit(), AbbreviationDecl,
AbbrevWriter, RangesBase);
convertToRangesPatchDebugInfo(DIE, DebugRangesOffset, DebugInfoPatcher,
LowPCToUse, RangesBase);
} else {
if (opts::Verbosity >= 1)
errs() << "BOLT-ERROR: cannot update ranges for DIE at offset 0x"
<< Twine::utohexstr(DIE.getOffset()) << '\n';
}
}
void DWARFRewriter::updateLineTableOffsets(const MCAsmLayout &Layout) {
ErrorOr<BinarySection &> DbgInfoSection =
BC.getUniqueSectionByName(".debug_info");
ErrorOr<BinarySection &> TypeInfoSection =
BC.getUniqueSectionByName(".debug_types");
assert(((BC.DwCtx->getNumTypeUnits() > 0 && TypeInfoSection) ||
BC.DwCtx->getNumTypeUnits() == 0) &&
"Was not able to retrieve Debug Types section.");
// We will be re-writing .debug_info so relocation mechanism doesn't work for
// Debug Info Patcher.
DebugInfoBinaryPatcher *DebugInfoPatcher = nullptr;
if (BC.DwCtx->getNumCompileUnits()) {
DbgInfoSection->registerPatcher(std::make_unique<DebugInfoBinaryPatcher>());
DebugInfoPatcher =
static_cast<DebugInfoBinaryPatcher *>(DbgInfoSection->getPatcher());
}
// There is no direct connection between CU and TU, but same offsets,
// encoded in DW_AT_stmt_list, into .debug_line get modified.
// We take advantage of that to map original CU line table offsets to new
// ones.
std::unordered_map<uint64_t, uint64_t> DebugLineOffsetMap;
auto GetStatementListValue = [](DWARFUnit *Unit) {
std::optional<DWARFFormValue> StmtList =
Unit->getUnitDIE().find(dwarf::DW_AT_stmt_list);
std::optional<uint64_t> Offset = dwarf::toSectionOffset(StmtList);
assert(Offset && "Was not able to retreive value of DW_AT_stmt_list.");
return *Offset;
};
const uint64_t Reloc32Type = BC.isAArch64()
? static_cast<uint64_t>(ELF::R_AARCH64_ABS32)
: static_cast<uint64_t>(ELF::R_X86_64_32);
for (const std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
const unsigned CUID = CU->getOffset();
MCSymbol *Label = BC.getDwarfLineTable(CUID).getLabel();
if (!Label)
continue;
std::optional<AttrInfo> AttrVal =
findAttributeInfo(CU.get()->getUnitDIE(), dwarf::DW_AT_stmt_list);
if (!AttrVal)
continue;
const uint64_t AttributeOffset = AttrVal->Offset;
const uint64_t LineTableOffset = Layout.getSymbolOffset(*Label);
DebugLineOffsetMap[GetStatementListValue(CU.get())] = LineTableOffset;
assert(DbgInfoSection && ".debug_info section must exist");
DebugInfoPatcher->addLE32Patch(AttributeOffset, LineTableOffset);
}
for (const std::unique_ptr<DWARFUnit> &TU : BC.DwCtx->types_section_units()) {
DWARFUnit *Unit = TU.get();
std::optional<AttrInfo> AttrVal =
findAttributeInfo(TU.get()->getUnitDIE(), dwarf::DW_AT_stmt_list);
if (!AttrVal)
continue;
const uint64_t AttributeOffset = AttrVal->Offset;
auto Iter = DebugLineOffsetMap.find(GetStatementListValue(Unit));
assert(Iter != DebugLineOffsetMap.end() &&
"Type Unit Updated Line Number Entry does not exist.");
TypeInfoSection->addRelocation(AttributeOffset, nullptr, Reloc32Type,
Iter->second, 0, /*Pending=*/true);
}
// Set .debug_info as finalized so it won't be skipped over when
// we process sections while writing out the new binary. This ensures
// that the pending relocations will be processed and not ignored.
if (DbgInfoSection)
DbgInfoSection->setIsFinalized();
if (TypeInfoSection)
TypeInfoSection->setIsFinalized();
}
CUOffsetMap
DWARFRewriter::finalizeDebugSections(DebugInfoBinaryPatcher &DebugInfoPatcher) {
if (StrWriter->isInitialized()) {
RewriteInstance::addToDebugSectionsToOverwrite(".debug_str");
std::unique_ptr<DebugStrBufferVector> DebugStrSectionContents =
StrWriter->releaseBuffer();
BC.registerOrUpdateNoteSection(".debug_str",
copyByteArray(*DebugStrSectionContents),
DebugStrSectionContents->size());
}
if (StrOffstsWriter->isFinalized()) {
RewriteInstance::addToDebugSectionsToOverwrite(".debug_str_offsets");
std::unique_ptr<DebugStrOffsetsBufferVector>
DebugStrOffsetsSectionContents = StrOffstsWriter->releaseBuffer();
BC.registerOrUpdateNoteSection(
".debug_str_offsets", copyByteArray(*DebugStrOffsetsSectionContents),
DebugStrOffsetsSectionContents->size());
}
if (BC.isDWARFLegacyUsed()) {
std::unique_ptr<DebugBufferVector> RangesSectionContents =
LegacyRangesSectionWriter->releaseBuffer();
BC.registerOrUpdateNoteSection(".debug_ranges",
copyByteArray(*RangesSectionContents),
RangesSectionContents->size());
}
if (BC.isDWARF5Used()) {
std::unique_ptr<DebugBufferVector> RangesSectionContents =
RangeListsSectionWriter->releaseBuffer();
BC.registerOrUpdateNoteSection(".debug_rnglists",
copyByteArray(*RangesSectionContents),
RangesSectionContents->size());
}
if (BC.isDWARF5Used()) {
std::unique_ptr<DebugBufferVector> LocationListSectionContents =
makeFinalLocListsSection(DebugInfoPatcher, DWARFVersion::DWARF5);
if (!LocationListSectionContents->empty())
BC.registerOrUpdateNoteSection(
".debug_loclists", copyByteArray(*LocationListSectionContents),
LocationListSectionContents->size());
}
if (BC.isDWARFLegacyUsed()) {
std::unique_ptr<DebugBufferVector> LocationListSectionContents =
makeFinalLocListsSection(DebugInfoPatcher, DWARFVersion::DWARFLegacy);
if (!LocationListSectionContents->empty())
BC.registerOrUpdateNoteSection(
".debug_loc", copyByteArray(*LocationListSectionContents),
LocationListSectionContents->size());
}
// AddrWriter should be finalized after debug_loc since more addresses can be
// added there.
if (AddrWriter->isInitialized()) {
AddressSectionBuffer AddressSectionContents = AddrWriter->finalize();
BC.registerOrUpdateNoteSection(".debug_addr",
copyByteArray(AddressSectionContents),
AddressSectionContents.size());
for (auto &CU : BC.DwCtx->compile_units()) {
DWARFDie DIE = CU->getUnitDIE();
uint64_t Offset = 0;
uint64_t AttrOffset = 0;
uint32_t Size = 0;
std::optional<AttrInfo> AttrValGnu =
findAttributeInfo(DIE, dwarf::DW_AT_GNU_addr_base);
std::optional<AttrInfo> AttrVal =
findAttributeInfo(DIE, dwarf::DW_AT_addr_base);
// For cases where Skeleton CU does not have DW_AT_GNU_addr_base
if (!AttrValGnu && CU->getVersion() < 5)
continue;
if (!AttrVal && CU->getVersion() >= 5 && !AddrWriter->doesCUExist(*CU))
continue;
Offset = AddrWriter->getOffset(*CU);
if (AttrValGnu) {
AttrOffset = AttrValGnu->Offset;
Size = AttrValGnu->Size;
}
if (AttrVal) {
AttrOffset = AttrVal->Offset;
Size = AttrVal->Size;
}
if (AttrValGnu || AttrVal) {
DebugInfoPatcher.addLE32Patch(AttrOffset, static_cast<int32_t>(Offset),
Size);
} else if (CU->getVersion() >= 5) {
// A case where we were not using .debug_addr section, but after update
// now using it.
const DWARFAbbreviationDeclaration *Abbrev =
DIE.getAbbreviationDeclarationPtr();
AbbrevWriter->addAttribute(*CU, Abbrev, dwarf::DW_AT_addr_base,
dwarf::DW_FORM_sec_offset);
DebugInfoPatcher.insertNewEntry(DIE, static_cast<int32_t>(Offset));
}
}
}
std::unique_ptr<DebugBufferVector> AbbrevSectionContents =
AbbrevWriter->finalize();
BC.registerOrUpdateNoteSection(".debug_abbrev",
copyByteArray(*AbbrevSectionContents),
AbbrevSectionContents->size());
// Update abbreviation offsets for CUs/TUs if they were changed.
SimpleBinaryPatcher *DebugTypesPatcher = nullptr;
for (auto &Unit : BC.DwCtx->normal_units()) {
const uint64_t NewAbbrevOffset =
AbbrevWriter->getAbbreviationsOffsetForUnit(*Unit);
if (Unit->getAbbreviationsOffset() == NewAbbrevOffset)
continue;
// DWARFv4 or earlier
// unit_length - 4 bytes
// version - 2 bytes
// So + 6 to patch debug_abbrev_offset
constexpr uint64_t AbbrevFieldOffsetLegacy = 6;
// DWARFv5
// unit_length - 4 bytes
// version - 2 bytes
// unit_type - 1 byte
// address_size - 1 byte
// So + 8 to patch debug_abbrev_offset
constexpr uint64_t AbbrevFieldOffsetV5 = 8;
uint64_t AbbrevOffset =
Unit->getVersion() >= 5 ? AbbrevFieldOffsetV5 : AbbrevFieldOffsetLegacy;
if (!Unit->isTypeUnit() || Unit->getVersion() >= 5) {
DebugInfoPatcher.addLE32Patch(Unit->getOffset() + AbbrevOffset,
static_cast<uint32_t>(NewAbbrevOffset));
continue;
}
if (!DebugTypesPatcher) {
ErrorOr<BinarySection &> DebugTypes =
BC.getUniqueSectionByName(".debug_types");
DebugTypes->registerPatcher(std::make_unique<SimpleBinaryPatcher>());
DebugTypesPatcher =
static_cast<SimpleBinaryPatcher *>(DebugTypes->getPatcher());
}
DebugTypesPatcher->addLE32Patch(Unit->getOffset() + AbbrevOffset,
static_cast<uint32_t>(NewAbbrevOffset));
}
// No more creating new DebugInfoPatches.
CUOffsetMap CUMap =
DebugInfoPatcher.computeNewOffsets(*BC.DwCtx.get(), false);
// Skip .debug_aranges if we are re-generating .gdb_index.
if (opts::KeepARanges || !BC.getGdbIndexSection()) {
SmallVector<char, 16> ARangesBuffer;
raw_svector_ostream OS(ARangesBuffer);
auto MAB = std::unique_ptr<MCAsmBackend>(
BC.TheTarget->createMCAsmBackend(*BC.STI, *BC.MRI, MCTargetOptions()));
ARangesSectionWriter->writeARangesSection(OS, CUMap);
const StringRef &ARangesContents = OS.str();
BC.registerOrUpdateNoteSection(".debug_aranges",
copyByteArray(ARangesContents),
ARangesContents.size());
}
return CUMap;
}
// Creates all the data structures necessary for creating MCStreamer.
// They are passed by reference because they need to be kept around.
// Also creates known debug sections. These are sections handled by
// handleDebugDataPatching.
using KnownSectionsEntry = std::pair<MCSection *, DWARFSectionKind>;
namespace {
std::unique_ptr<BinaryContext>
createDwarfOnlyBC(const object::ObjectFile &File) {
return cantFail(BinaryContext::createBinaryContext(
&File, false,
DWARFContext::create(File, DWARFContext::ProcessDebugRelocations::Ignore,
nullptr, "", WithColor::defaultErrorHandler,
WithColor::defaultWarningHandler)));
}
StringMap<KnownSectionsEntry>
createKnownSectionsMap(const MCObjectFileInfo &MCOFI) {
StringMap<KnownSectionsEntry> KnownSectionsTemp = {
{"debug_info.dwo", {MCOFI.getDwarfInfoDWOSection(), DW_SECT_INFO}},
{"debug_types.dwo", {MCOFI.getDwarfTypesDWOSection(), DW_SECT_EXT_TYPES}},
{"debug_str_offsets.dwo",
{MCOFI.getDwarfStrOffDWOSection(), DW_SECT_STR_OFFSETS}},
{"debug_str.dwo", {MCOFI.getDwarfStrDWOSection(), DW_SECT_EXT_unknown}},
{"debug_loc.dwo", {MCOFI.getDwarfLocDWOSection(), DW_SECT_EXT_LOC}},
{"debug_abbrev.dwo", {MCOFI.getDwarfAbbrevDWOSection(), DW_SECT_ABBREV}},
{"debug_line.dwo", {MCOFI.getDwarfLineDWOSection(), DW_SECT_LINE}},
{"debug_loclists.dwo",
{MCOFI.getDwarfLoclistsDWOSection(), DW_SECT_LOCLISTS}},
{"debug_rnglists.dwo",
{MCOFI.getDwarfRnglistsDWOSection(), DW_SECT_RNGLISTS}}};
return KnownSectionsTemp;
}
StringRef getSectionName(const SectionRef &Section) {
Expected<StringRef> SectionName = Section.getName();
assert(SectionName && "Invalid section name.");
StringRef Name = *SectionName;
Name = Name.substr(Name.find_first_not_of("._"));
return Name;
}
// Exctracts an appropriate slice if input is DWP.
// Applies patches or overwrites the section.
std::optional<StringRef>
updateDebugData(DWARFContext &DWCtx, std::string &Storage,
StringRef SectionName, StringRef SectionContents,
const StringMap<KnownSectionsEntry> &KnownSections,
MCStreamer &Streamer, DWARFRewriter &Writer,
const DWARFUnitIndex::Entry *CUDWOEntry, uint64_t DWOId,
std::unique_ptr<DebugBufferVector> &OutputBuffer,
DebugRangeListsSectionWriter *RangeListsWriter) {
auto applyPatch = [&](DebugInfoBinaryPatcher *Patcher,
StringRef Data) -> StringRef {
Patcher->computeNewOffsets(DWCtx, true);
Storage = Patcher->patchBinary(Data);
return StringRef(Storage.c_str(), Storage.size());
};
using DWOSectionContribution =
const DWARFUnitIndex::Entry::SectionContribution;
auto getSliceData = [&](const DWARFUnitIndex::Entry *DWOEntry,
StringRef OutData, DWARFSectionKind Sec,
uint64_t &DWPOffset) -> StringRef {
if (DWOEntry) {
DWOSectionContribution *DWOContrubution = DWOEntry->getContribution(Sec);
DWPOffset = DWOContrubution->getOffset();
OutData = OutData.substr(DWPOffset, DWOContrubution->getLength());
}
return OutData;
};
auto SectionIter = KnownSections.find(SectionName);
if (SectionIter == KnownSections.end())
return std::nullopt;
Streamer.switchSection(SectionIter->second.first);
StringRef OutData = SectionContents;
uint64_t DWPOffset = 0;
switch (SectionIter->second.second) {
default: {
if (!SectionName.equals("debug_str.dwo"))
errs() << "BOLT-WARNING: unsupported debug section: " << SectionName
<< "\n";
return OutData;
}
case DWARFSectionKind::DW_SECT_INFO: {
OutData = getSliceData(CUDWOEntry, OutData, DWARFSectionKind::DW_SECT_INFO,
DWPOffset);
DebugInfoBinaryPatcher *Patcher = llvm::cast<DebugInfoBinaryPatcher>(
Writer.getBinaryDWODebugInfoPatcher(DWOId));
return applyPatch(Patcher, OutData);
}
case DWARFSectionKind::DW_SECT_EXT_TYPES: {
return getSliceData(nullptr, OutData, DWARFSectionKind::DW_SECT_EXT_TYPES,
DWPOffset);
}
case DWARFSectionKind::DW_SECT_STR_OFFSETS: {
return getSliceData(CUDWOEntry, OutData,
DWARFSectionKind::DW_SECT_STR_OFFSETS, DWPOffset);
}
case DWARFSectionKind::DW_SECT_ABBREV: {
DebugAbbrevWriter *AbbrevWriter = Writer.getBinaryDWOAbbrevWriter(DWOId);
OutputBuffer = AbbrevWriter->finalize();
// Creating explicit StringRef here, otherwise
// with impicit conversion it will take null byte as end of
// string.
return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
OutputBuffer->size());
}
case DWARFSectionKind::DW_SECT_EXT_LOC:
case DWARFSectionKind::DW_SECT_LOCLISTS: {
DebugLocWriter *LocWriter = Writer.getDebugLocWriter(DWOId);
OutputBuffer = LocWriter->getBuffer();
// Creating explicit StringRef here, otherwise
// with impicit conversion it will take null byte as end of
// string.
return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
OutputBuffer->size());
}
case DWARFSectionKind::DW_SECT_LINE: {
return getSliceData(CUDWOEntry, OutData, DWARFSectionKind::DW_SECT_LINE,
DWPOffset);
}
case DWARFSectionKind::DW_SECT_RNGLISTS: {
OutputBuffer = RangeListsWriter->releaseBuffer();
return StringRef(reinterpret_cast<const char *>(OutputBuffer->data()),
OutputBuffer->size());
}
}
}
} // namespace
struct TUContribution {
uint64_t Signature{0};
uint32_t Length{0};
};
using TUContributionVector = std::vector<TUContribution>;
/// Iterates over all the signatures used in this CU, and
/// uses TU Index to extract their contributions from the DWP file.
/// It stores them in DWOTUSection.
static std::string extractDWOTUFromDWP(
const DWARFRewriter::DebugTypesSignaturesPerCUMap &TypeSignaturesPerCU,
const DWARFUnitIndex &TUIndex, StringRef Contents,
TUContributionVector &TUContributionsToCU, uint64_t DWOId) {
std::string DWOTUSection;
using TUEntry =
std::pair<uint64_t, const DWARFUnitIndex::Entry::SectionContribution *>;
std::vector<TUEntry> TUContributions;
for (const uint64_t TUSignature : TypeSignaturesPerCU.at(DWOId)) {
const DWARFUnitIndex::Entry *TUDWOEntry = TUIndex.getFromHash(TUSignature);
const DWARFUnitIndex::Entry::SectionContribution *C =
TUDWOEntry->getContribution(DW_SECT_EXT_TYPES);
TUContributions.emplace_back(TUSignature, C);
}
// Sorting so it's easy to compare output.
// They should be sharing the same Abbrev.
llvm::sort(TUContributions, [](const TUEntry &V1, const TUEntry &V2) -> bool {
return V1.second->getOffset() < V2.second->getOffset();
});
for (auto &PairEntry : TUContributions) {
const DWARFUnitIndex::Entry::SectionContribution *C = PairEntry.second;
const uint64_t TUSignature = PairEntry.first;
DWOTUSection.append(
Contents.slice(C->getOffset(), C->getOffset() + C->getLength()).str());
TUContributionsToCU.push_back({TUSignature, C->getLength32()});
}
return DWOTUSection;
}
static void extractDWOTUFromDWO(StringRef Contents,
TUContributionVector &TUContributionsToCU) {
uint64_t Offset = 0;
DataExtractor Data(Contents, true, 0);
while (Data.isValidOffset(Offset)) {
auto PrevOffset = Offset;
// Length of the unit, including the 4 byte length field.
const uint32_t Length = Data.getU32(&Offset) + 4;
Data.getU16(&Offset); // Version
Data.getU32(&Offset); // Abbrev offset
Data.getU8(&Offset); // Address size
const auto TUSignature = Data.getU64(&Offset);
Offset = PrevOffset + Length;
TUContributionsToCU.push_back({TUSignature, Length});
}
}
static void extractTypesFromDWPDWARF5(
const MCObjectFileInfo &MCOFI, const DWARFUnitIndex &TUIndex,
const DWARFRewriter::DebugTypesSignaturesPerCUMap &TypeSignaturesPerCU,
MCStreamer &Streamer, StringRef Contents, uint64_t DWOId) {
std::vector<const DWARFUnitIndex::Entry::SectionContribution *>
TUContributions;
for (const uint64_t Val : TypeSignaturesPerCU.at(DWOId)) {
const DWARFUnitIndex::Entry *TUE = TUIndex.getFromHash(Val);
const DWARFUnitIndex::Entry::SectionContribution *C =
TUE->getContribution(DWARFSectionKind::DW_SECT_INFO);
TUContributions.push_back(C);
}
// Sorting so it's easy to compare output.
// They should be sharing the same Abbrev.
llvm::sort(TUContributions,
[](const DWARFUnitIndex::Entry::SectionContribution *V1,
const DWARFUnitIndex::Entry::SectionContribution *V2) -> bool {
return V1->getOffset() < V2->getOffset();
});
Streamer.switchSection(MCOFI.getDwarfInfoDWOSection());
for (const auto *C : TUContributions)
Streamer.emitBytes(
Contents.slice(C->getOffset(), C->getOffset() + C->getLength()));
}
void DWARFRewriter::writeDWP(
std::unordered_map<uint64_t, std::string> &DWOIdToName) {
SmallString<0> OutputNameStr;
StringRef OutputName;
if (opts::DwarfOutputPath.empty()) {
OutputName =
Twine(opts::OutputFilename).concat(".dwp").toStringRef(OutputNameStr);
} else {
StringRef ExeFileName = llvm::sys::path::filename(opts::OutputFilename);
OutputName = Twine(opts::DwarfOutputPath)
.concat("/")
.concat(ExeFileName)
.concat(".dwp")
.toStringRef(OutputNameStr);
errs() << "BOLT-WARNING: dwarf-output-path is in effect and .dwp file will "
"possibly be written to another location that is not the same as "
"the executable\n";
}
std::error_code EC;
std::unique_ptr<ToolOutputFile> Out =
std::make_unique<ToolOutputFile>(OutputName, EC, sys::fs::OF_None);
const object::ObjectFile *File = BC.DwCtx->getDWARFObj().getFile();
std::unique_ptr<BinaryContext> TmpBC = createDwarfOnlyBC(*File);
std::unique_ptr<MCStreamer> Streamer = TmpBC->createStreamer(Out->os());
const MCObjectFileInfo &MCOFI = *Streamer->getContext().getObjectFileInfo();
StringMap<KnownSectionsEntry> KnownSections = createKnownSectionsMap(MCOFI);
MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
// Data Structures for DWP book keeping
// Size of array corresponds to the number of sections supported by DWO format
// in DWARF4/5.
uint32_t ContributionOffsets[8] = {};
std::deque<SmallString<32>> UncompressedSections;
DWPStringPool Strings(*Streamer, StrSection);
MapVector<uint64_t, UnitIndexEntry> IndexEntries;
MapVector<uint64_t, UnitIndexEntry> TypeIndexEntries;
uint16_t Version = 0;
uint32_t IndexVersion = 2;
// Setup DWP code once.
DWARFContext *DWOCtx = BC.getDWOContext();
const DWARFUnitIndex *CUIndex = nullptr;
const DWARFUnitIndex *TUIndex = nullptr;
bool IsDWP = false;
if (DWOCtx) {
CUIndex = &DWOCtx->getCUIndex();
TUIndex = &DWOCtx->getTUIndex();
IsDWP = !CUIndex->getRows().empty();
}
for (const std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
std::optional<uint64_t> DWOId = CU->getDWOId();
if (!DWOId)
continue;
// Skipping CUs that we failed to load.
std::optional<DWARFUnit *> DWOCU = BC.getDWOCU(*DWOId);
if (!DWOCU)
continue;
if (Version == 0) {
Version = CU->getVersion();
IndexVersion = Version < 5 ? 2 : 5;
} else if (Version != CU->getVersion()) {
errs() << "BOLT-ERROR: Incompatible DWARF compile unit versions.\n";
exit(1);
}
UnitIndexEntry CurEntry = {};
CurEntry.DWOName =
dwarf::toString(CU->getUnitDIE().find(
{dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}),
"");
const char *Name = CU->getUnitDIE().getShortName();
if (Name)
CurEntry.Name = Name;
StringRef CurStrSection;
StringRef CurStrOffsetSection;
// This maps each section contained in this file to its length.
// This information is later on used to calculate the contributions,
// i.e. offset and length, of each compile/type unit to a section.
std::vector<std::pair<DWARFSectionKind, uint32_t>> SectionLength;
const DWARFUnitIndex::Entry *CUDWOEntry = nullptr;
if (IsDWP)
CUDWOEntry = CUIndex->getFromHash(*DWOId);
bool StrSectionWrittenOut = false;
const object::ObjectFile *DWOFile =
(*DWOCU)->getContext().getDWARFObj().getFile();
DebugRangeListsSectionWriter *RangeListssWriter = nullptr;
if (CU->getVersion() == 5) {
assert(RangeListsWritersByCU.count(*DWOId) != 0 &&
"No RangeListsWriter for DWO ID.");
RangeListssWriter = RangeListsWritersByCU[*DWOId].get();
}
std::string DWOTUSection;
TUContributionVector TUContributionsToCU;
for (const SectionRef &Section : DWOFile->sections()) {
std::string DWOTUSection;
std::string Storage;
std::unique_ptr<DebugBufferVector> OutputData;
StringRef SectionName = getSectionName(Section);
Expected<StringRef> ContentsExp = Section.getContents();
assert(ContentsExp && "Invalid contents.");
StringRef Contents = *ContentsExp;
const bool IsTypesDWO = SectionName == "debug_types.dwo";
if (IsDWP && IsTypesDWO) {
assert(TUIndex &&
"DWP Input with .debug_types.dwo section with TU Index.");
DWOTUSection =
extractDWOTUFromDWP(TypeSignaturesPerCU, *TUIndex, Contents,
TUContributionsToCU, *DWOId);
Contents = DWOTUSection;
} else if (IsTypesDWO) {
extractDWOTUFromDWO(Contents, TUContributionsToCU);
}
std::optional<StringRef> TOutData = updateDebugData(
(*DWOCU)->getContext(), Storage, SectionName, Contents, KnownSections,
*Streamer, *this, CUDWOEntry, *DWOId, OutputData, RangeListssWriter);
if (!TOutData)
continue;
StringRef OutData = *TOutData;
if (IsTypesDWO) {
Streamer->emitBytes(OutData);
continue;
}
if (SectionName.equals("debug_str.dwo")) {
CurStrSection = OutData;
} else {
// Since handleDebugDataPatching returned true, we already know this is
// a known section.
auto SectionIter = KnownSections.find(SectionName);
if (SectionIter->second.second == DWARFSectionKind::DW_SECT_STR_OFFSETS)
CurStrOffsetSection = OutData;
else
Streamer->emitBytes(OutData);
auto Index =
getContributionIndex(SectionIter->second.second, IndexVersion);
CurEntry.Contributions[Index].setOffset(ContributionOffsets[Index]);
CurEntry.Contributions[Index].setLength(OutData.size());
ContributionOffsets[Index] +=
CurEntry.Contributions[Index].getLength32();
}
// Strings are combined in to a new string section, and de-duplicated
// based on hash.
if (!StrSectionWrittenOut && !CurStrOffsetSection.empty() &&
!CurStrSection.empty()) {
writeStringsAndOffsets(*Streamer.get(), Strings, StrOffsetSection,
CurStrSection, CurStrOffsetSection,
CU->getVersion());
StrSectionWrittenOut = true;
}
}
CompileUnitIdentifiers CUI{*DWOId, CurEntry.Name.c_str(),
CurEntry.DWOName.c_str()};
auto P = IndexEntries.insert(std::make_pair(CUI.Signature, CurEntry));
if (!P.second) {
Error Err = buildDuplicateError(*P.first, CUI, "");
errs() << "BOLT-ERROR: " << toString(std::move(Err)) << "\n";
return;
}
// Handling TU
if (!TUContributionsToCU.empty()) {
const unsigned Index =
getContributionIndex(DW_SECT_EXT_TYPES, IndexVersion);
for (const TUContribution &TUC : TUContributionsToCU) {
UnitIndexEntry TUEntry = CurEntry;
TUEntry.Contributions[0] = {};
TUEntry.Contributions[Index].setOffset(ContributionOffsets[Index]);
TUEntry.Contributions[Index].setLength(TUC.Length);
ContributionOffsets[Index] +=
TUEntry.Contributions[Index].getLength32();
TypeIndexEntries.insert(std::make_pair(TUC.Signature, TUEntry));
}
}
}
if (Version < 5) {
// Lie about there being no info contributions so the TU index only includes
// the type unit contribution for DWARF < 5. In DWARFv5 the TU index has a
// contribution to the info section, so we do not want to lie about it.
ContributionOffsets[0] = 0;
}
writeIndex(*Streamer.get(), MCOFI.getDwarfTUIndexSection(),
ContributionOffsets, TypeIndexEntries, IndexVersion);
if (Version < 5) {
// Lie about the type contribution for DWARF < 5. In DWARFv5 the type
// section does not exist, so no need to do anything about this.
ContributionOffsets[getContributionIndex(DW_SECT_EXT_TYPES, 2)] = 0;
// Unlie about the info contribution
ContributionOffsets[0] = 1;
}
writeIndex(*Streamer.get(), MCOFI.getDwarfCUIndexSection(),
ContributionOffsets, IndexEntries, IndexVersion);
Streamer->finish();
Out->keep();
}
void DWARFRewriter::writeDWOFiles(
std::unordered_map<uint64_t, std::string> &DWOIdToName) {
// Setup DWP code once.
DWARFContext *DWOCtx = BC.getDWOContext();
const DWARFUnitIndex *CUIndex = nullptr;
const DWARFUnitIndex *TUIndex = nullptr;
bool IsDWP = false;
if (DWOCtx) {
CUIndex = &DWOCtx->getCUIndex();
TUIndex = &DWOCtx->getTUIndex();
IsDWP = !CUIndex->getRows().empty();
}
for (const std::unique_ptr<DWARFUnit> &CU : BC.DwCtx->compile_units()) {
std::optional<uint64_t> DWOId = CU->getDWOId();
if (!DWOId)
continue;
// Skipping CUs that we failed to load.
std::optional<DWARFUnit *> DWOCU = BC.getDWOCU(*DWOId);
if (!DWOCU)
continue;
std::string CompDir = opts::DwarfOutputPath.empty()
? CU->getCompilationDir()
: opts::DwarfOutputPath.c_str();
std::string ObjectName = getDWOName(*CU.get(), nullptr, DWOIdToName);
auto FullPath = CompDir.append("/").append(ObjectName);
std::error_code EC;
std::unique_ptr<ToolOutputFile> TempOut =
std::make_unique<ToolOutputFile>(FullPath, EC, sys::fs::OF_None);
const DWARFUnitIndex::Entry *CUDWOEntry = nullptr;
if (IsDWP)
CUDWOEntry = CUIndex->getFromHash(*DWOId);
const object::ObjectFile *File =
(*DWOCU)->getContext().getDWARFObj().getFile();
std::unique_ptr<BinaryContext> TmpBC = createDwarfOnlyBC(*File);
std::unique_ptr<MCStreamer> Streamer = TmpBC->createStreamer(TempOut->os());
const MCObjectFileInfo &MCOFI = *Streamer->getContext().getObjectFileInfo();
StringMap<KnownSectionsEntry> KnownSections = createKnownSectionsMap(MCOFI);
DebugRangeListsSectionWriter *RangeListssWriter = nullptr;
if (CU->getVersion() == 5) {
assert(RangeListsWritersByCU.count(*DWOId) != 0 &&
"No RangeListsWriter for DWO ID.");
RangeListssWriter = RangeListsWritersByCU[*DWOId].get();
// Handling .debug_rnglists.dwo seperatly. The original .o/.dwo might not
// have .debug_rnglists so won't be part of the loop below.
if (!RangeListssWriter->empty()) {
std::string Storage;
std::unique_ptr<DebugBufferVector> OutputData;
if (std::optional<StringRef> OutData = updateDebugData(
(*DWOCU)->getContext(), Storage, "debug_rnglists.dwo", "",
KnownSections, *Streamer, *this, CUDWOEntry, *DWOId, OutputData,
RangeListssWriter))
Streamer->emitBytes(*OutData);
}
}
TUContributionVector TUContributionsToCU;
for (const SectionRef &Section : File->sections()) {
std::string Storage;
std::string DWOTUSection;
std::unique_ptr<DebugBufferVector> OutputData;
StringRef SectionName = getSectionName(Section);
if (SectionName == "debug_rnglists.dwo")
continue;
Expected<StringRef> ContentsExp = Section.getContents();
assert(ContentsExp && "Invalid contents.");
StringRef Contents = *ContentsExp;
if (IsDWP && SectionName == "debug_types.dwo") {
assert(TUIndex &&
"DWP Input with .debug_types.dwo section with TU Index.");
DWOTUSection =
extractDWOTUFromDWP(TypeSignaturesPerCU, *TUIndex, Contents,
TUContributionsToCU, *DWOId);
Contents = DWOTUSection;
} else if (IsDWP && CU->getVersion() >= 5 &&
SectionName == "debug_info.dwo") {
assert(TUIndex &&
"DWP Input with .debug_types.dwo section with TU Index.");
extractTypesFromDWPDWARF5(MCOFI, *TUIndex, TypeSignaturesPerCU,
*Streamer, Contents, *DWOId);
}
if (std::optional<StringRef> OutData = updateDebugData(
(*DWOCU)->getContext(), Storage, SectionName, Contents,
KnownSections, *Streamer, *this, CUDWOEntry, *DWOId, OutputData,
RangeListssWriter))
Streamer->emitBytes(*OutData);
}
Streamer->finish();
TempOut->keep();
}
}
void DWARFRewriter::updateGdbIndexSection(CUOffsetMap &CUMap) {
if (!BC.getGdbIndexSection())
return;
// See https://sourceware.org/gdb/onlinedocs/gdb/Index-Section-Format.html
// for .gdb_index section format.
StringRef GdbIndexContents = BC.getGdbIndexSection()->getContents();
const char *Data = GdbIndexContents.data();
// Parse the header.
const uint32_t Version = read32le(Data);
if (Version != 7 && Version != 8) {
errs() << "BOLT-ERROR: can only process .gdb_index versions 7 and 8\n";
exit(1);
}
// Some .gdb_index generators use file offsets while others use section
// offsets. Hence we can only rely on offsets relative to each other,
// and ignore their absolute values.
const uint32_t CUListOffset = read32le(Data + 4);
const uint32_t CUTypesOffset = read32le(Data + 8);
const uint32_t AddressTableOffset = read32le(Data + 12);
const uint32_t SymbolTableOffset = read32le(Data + 16);
const uint32_t ConstantPoolOffset = read32le(Data + 20);
Data += 24;
// Map CUs offsets to indices and verify existing index table.
std::map<uint32_t, uint32_t> OffsetToIndexMap;
const uint32_t CUListSize = CUTypesOffset - CUListOffset;
const unsigned NumCUs = BC.DwCtx->getNumCompileUnits();
if (CUListSize != NumCUs * 16) {
errs() << "BOLT-ERROR: .gdb_index: CU count mismatch\n";
exit(1);
}
for (unsigned Index = 0; Index < NumCUs; ++Index, Data += 16) {
const DWARFUnit *CU = BC.DwCtx->getUnitAtIndex(Index);
const uint64_t Offset = read64le(Data);
if (CU->getOffset() != Offset) {
errs() << "BOLT-ERROR: .gdb_index CU offset mismatch\n";
exit(1);
}
OffsetToIndexMap[Offset] = Index;
}
// Ignore old address table.
const uint32_t OldAddressTableSize = SymbolTableOffset - AddressTableOffset;
// Move Data to the beginning of symbol table.
Data += SymbolTableOffset - CUTypesOffset;
// Calculate the size of the new address table.
uint32_t NewAddressTableSize = 0;
for (const auto &CURangesPair : ARangesSectionWriter->getCUAddressRanges()) {
const SmallVector<DebugAddressRange, 2> &Ranges = CURangesPair.second;
NewAddressTableSize += Ranges.size() * 20;
}
// Difference between old and new table (and section) sizes.
// Could be negative.
int32_t Delta = NewAddressTableSize - OldAddressTableSize;
size_t NewGdbIndexSize = GdbIndexContents.size() + Delta;
// Free'd by ExecutableFileMemoryManager.
auto *NewGdbIndexContents = new uint8_t[NewGdbIndexSize];
uint8_t *Buffer = NewGdbIndexContents;
write32le(Buffer, Version);
write32le(Buffer + 4, CUListOffset);
write32le(Buffer + 8, CUTypesOffset);
write32le(Buffer + 12, AddressTableOffset);
write32le(Buffer + 16, SymbolTableOffset + Delta);
write32le(Buffer + 20, ConstantPoolOffset + Delta);
Buffer += 24;
// Writing out CU List <Offset, Size>
for (auto &CUInfo : CUMap) {
write64le(Buffer, CUInfo.second.Offset);
// Length encoded in CU doesn't contain first 4 bytes that encode length.
write64le(Buffer + 8, CUInfo.second.Length + 4);
Buffer += 16;
}
// Copy over types CU list
// Spec says " triplet, the first value is the CU offset, the second value is
// the type offset in the CU, and the third value is the type signature"
// Looking at what is being generated by gdb-add-index. The first entry is TU
// offset, second entry is offset from it, and third entry is the type
// signature.
memcpy(Buffer, GdbIndexContents.data() + CUTypesOffset,
AddressTableOffset - CUTypesOffset);
Buffer += AddressTableOffset - CUTypesOffset;
// Generate new address table.
for (const std::pair<const uint64_t, DebugAddressRangesVector> &CURangesPair :
ARangesSectionWriter->getCUAddressRanges()) {
const uint32_t CUIndex = OffsetToIndexMap[CURangesPair.first];
const DebugAddressRangesVector &Ranges = CURangesPair.second;
for (const DebugAddressRange &Range : Ranges) {
write64le(Buffer, Range.LowPC);
write64le(Buffer + 8, Range.HighPC);
write32le(Buffer + 16, CUIndex);
Buffer += 20;
}
}
const size_t TrailingSize =
GdbIndexContents.data() + GdbIndexContents.size() - Data;
assert(Buffer + TrailingSize == NewGdbIndexContents + NewGdbIndexSize &&
"size calculation error");
// Copy over the rest of the original data.
memcpy(Buffer, Data, TrailingSize);
// Register the new section.
BC.registerOrUpdateNoteSection(".gdb_index", NewGdbIndexContents,
NewGdbIndexSize);
}
std::unique_ptr<DebugBufferVector> DWARFRewriter::makeFinalLocListsSection(
DebugInfoBinaryPatcher &DebugInfoPatcher, DWARFVersion Version) {
auto LocBuffer = std::make_unique<DebugBufferVector>();
auto LocStream = std::make_unique<raw_svector_ostream>(*LocBuffer);
auto Writer =
std::unique_ptr<MCObjectWriter>(BC.createObjectWriter(*LocStream));
for (std::pair<const uint64_t, std::unique_ptr<DebugLocWriter>> &Loc :
LocListWritersByCU) {
DebugLocWriter *LocWriter = Loc.second.get();
auto *LocListWriter = llvm::dyn_cast<DebugLoclistWriter>(LocWriter);
// Filter out DWARF4, writing out DWARF5
if (Version == DWARFVersion::DWARF5 &&
(!LocListWriter || LocListWriter->getDwarfVersion() <= 4))
continue;
// Filter out DWARF5, writing out DWARF4
if (Version == DWARFVersion::DWARFLegacy &&
(LocListWriter && LocListWriter->getDwarfVersion() >= 5))
continue;
// Skipping DWARF4/5 split dwarf.
if (LocListWriter && (LocListWriter->getDwarfVersion() <= 4 ||
(LocListWriter->getDwarfVersion() >= 5 &&
LocListWriter->isSplitDwarf()))) {
continue;
}
std::unique_ptr<DebugBufferVector> CurrCULocationLists =
LocWriter->getBuffer();
*LocStream << *CurrCULocationLists;
}
return LocBuffer;
}
namespace {
void getRangeAttrData(DWARFDie DIE, std::optional<AttrInfo> &LowPCVal,
std::optional<AttrInfo> &HighPCVal) {
LowPCVal = findAttributeInfo(DIE, dwarf::DW_AT_low_pc);
HighPCVal = findAttributeInfo(DIE, dwarf::DW_AT_high_pc);
uint64_t LowPCOffset = LowPCVal->Offset;
uint64_t HighPCOffset = HighPCVal->Offset;
dwarf::Form LowPCForm = LowPCVal->V.getForm();
dwarf::Form HighPCForm = HighPCVal->V.getForm();
if (LowPCForm != dwarf::DW_FORM_addr &&
LowPCForm != dwarf::DW_FORM_GNU_addr_index &&
LowPCForm != dwarf::DW_FORM_addrx) {
errs() << "BOLT-WARNING: unexpected low_pc form value. Cannot update DIE "
<< "at offset 0x" << Twine::utohexstr(DIE.getOffset()) << "\n";
return;
}
if (HighPCForm != dwarf::DW_FORM_addr && HighPCForm != dwarf::DW_FORM_data8 &&
HighPCForm != dwarf::DW_FORM_data4 &&
HighPCForm != dwarf::DW_FORM_data2 &&
HighPCForm != dwarf::DW_FORM_data1 &&
HighPCForm != dwarf::DW_FORM_udata) {
errs() << "BOLT-WARNING: unexpected high_pc form value. Cannot update DIE "
<< "at offset 0x" << Twine::utohexstr(DIE.getOffset()) << "\n";
return;
}
if ((LowPCOffset == -1U || (LowPCOffset + 8 != HighPCOffset)) &&
LowPCForm != dwarf::DW_FORM_GNU_addr_index &&
LowPCForm != dwarf::DW_FORM_addrx) {
errs() << "BOLT-WARNING: high_pc expected immediately after low_pc. "
<< "Cannot update DIE at offset 0x"
<< Twine::utohexstr(DIE.getOffset()) << '\n';
return;
}
}
} // namespace
void DWARFRewriter::convertToRangesPatchAbbrev(
const DWARFUnit &Unit, const DWARFAbbreviationDeclaration *Abbrev,
DebugAbbrevWriter &AbbrevWriter, std::optional<uint64_t> RangesBase) {
dwarf::Attribute RangeBaseAttribute = dwarf::DW_AT_GNU_ranges_base;
dwarf::Form RangesForm = dwarf::DW_FORM_sec_offset;
if (Unit.getVersion() >= 5) {
RangeBaseAttribute = dwarf::DW_AT_rnglists_base;
RangesForm = dwarf::DW_FORM_rnglistx;
}
// If we hit this point it means we converted subprogram DIEs from
// low_pc/high_pc into ranges. The CU originally didn't have DW_AT_*_base, so
// we are adding it here.
if (RangesBase)
AbbrevWriter.addAttribute(Unit, Abbrev, RangeBaseAttribute,
dwarf::DW_FORM_sec_offset);
// Converting DW_AT_high_pc into DW_AT_ranges.
// For DWARF4 it's DW_FORM_sec_offset.
// For DWARF5 it can be either DW_FORM_sec_offset or DW_FORM_rnglistx.
// For consistency for DWARF5 we always use DW_FORM_rnglistx.
AbbrevWriter.addAttributePatch(Unit, Abbrev, dwarf::DW_AT_high_pc,
dwarf::DW_AT_ranges, RangesForm);
}
void DWARFRewriter::convertToRangesPatchDebugInfo(
DWARFDie DIE, uint64_t RangesSectionOffset,
SimpleBinaryPatcher &DebugInfoPatcher, uint64_t LowPCToUse,
std::optional<uint64_t> RangesBase) {
std::optional<AttrInfo> LowPCVal;
std::optional<AttrInfo> HighPCVal;
getRangeAttrData(DIE, LowPCVal, HighPCVal);
uint64_t LowPCOffset = LowPCVal->Offset;
uint64_t HighPCOffset = HighPCVal->Offset;
std::lock_guard<std::mutex> Lock(DebugInfoPatcherMutex);
uint32_t BaseOffset = 0;
dwarf::Form LowForm = LowPCVal->V.getForm();
// In DWARF4 for DW_AT_low_pc in binary DW_FORM_addr is used. In the DWO
// section DW_FORM_GNU_addr_index is used. So for if we are converting
// DW_AT_low_pc/DW_AT_high_pc and see DW_FORM_GNU_addr_index. We are
// converting in DWO section, and DW_AT_ranges [DW_FORM_sec_offset] is
// relative to DW_AT_GNU_ranges_base.
if (LowForm == dwarf::DW_FORM_GNU_addr_index) {
// Use ULEB128 for the value.
DebugInfoPatcher.addUDataPatch(LowPCOffset, 0, LowPCVal->Size);
// Ranges are relative to DW_AT_GNU_ranges_base.
BaseOffset = DebugInfoPatcher.getRangeBase();
} else {
// In DWARF 5 we can have DW_AT_low_pc either as DW_FORM_addr, or
// DW_FORM_addrx. Former is when DW_AT_rnglists_base is present. Latter is
// when it's absent.
if (LowForm == dwarf::DW_FORM_addrx) {
const uint32_t Index =
AddrWriter->getIndexFromAddress(LowPCToUse, *DIE.getDwarfUnit());
DebugInfoPatcher.addUDataPatch(LowPCOffset, Index, LowPCVal->Size);
} else
DebugInfoPatcher.addLE64Patch(LowPCOffset, LowPCToUse);
// Original CU didn't have DW_AT_*_base. We converted it's children (or
// dwo), so need to insert it into CU.
if (RangesBase)
reinterpret_cast<DebugInfoBinaryPatcher &>(DebugInfoPatcher)
.insertNewEntry(DIE, *RangesBase);
}
// HighPC was conveted into DW_AT_ranges.
// For DWARF5 we only access ranges throught index.
if (DIE.getDwarfUnit()->getVersion() >= 5)
DebugInfoPatcher.addUDataPatch(HighPCOffset, RangesSectionOffset,
HighPCVal->Size);
else
DebugInfoPatcher.addLE32Patch(
HighPCOffset, RangesSectionOffset - BaseOffset, HighPCVal->Size);
}