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llvm-mirror/tools/dsymutil/DwarfLinkerForBinary.cpp
Jonas Devlieghere 5e66aeab68 [dsymutil] Add option to print statistics about the .debug_info size. 
This patch adds statistics about the contribution of each object file to
the linked debug info. When --statistics is passed to dsymutil, it
prints a table after linking as illustrated below.

It lists the object file name, the size of the debug info in the object
file in bytes, and the absolute size contribution to the linked dSYM and
the percentage difference. The table is sorted by the output size, so
the object files contributing the most to the link are listed first.

.debug_info section size (in bytes)
-------------------------------------------------------------------------------
Filename                                           Object         dSYM   Change
-------------------------------------------------------------------------------
basic2.macho.x86_64.o                                210b         165b  -24.00%
basic3.macho.x86_64.o                                177b         150b  -16.51%
basic1.macho.x86_64.o                                125b         129b    3.15%
-------------------------------------------------------------------------------
Total                                                512b         444b  -14.23%
-------------------------------------------------------------------------------

Differential revision: https://reviews.llvm.org/D79513
2020-05-06 19:48:45 -07:00

705 lines
26 KiB
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//===- tools/dsymutil/DwarfLinkerForBinary.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 "DwarfLinkerForBinary.h"
#include "BinaryHolder.h"
#include "DebugMap.h"
#include "MachOUtils.h"
#include "dsymutil.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/Twine.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/CodeGen/AccelTable.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/DIE.h"
#include "llvm/CodeGen/NonRelocatableStringpool.h"
#include "llvm/Config/config.h"
#include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
#include "llvm/DebugInfo/DWARF/DWARFDie.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
#include "llvm/MC/MCAsmBackend.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCCodeEmitter.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDwarf.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCObjectWriter.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCTargetOptions.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/SymbolicFile.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/DJB.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/LEB128.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/ThreadPool.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/MC/MCTargetOptionsCommandFlags.h"
#include <algorithm>
#include <cassert>
#include <cinttypes>
#include <climits>
#include <cstdint>
#include <cstdlib>
#include <cstring>
#include <limits>
#include <map>
#include <memory>
#include <string>
#include <system_error>
#include <tuple>
#include <utility>
#include <vector>
namespace llvm {
static mc::RegisterMCTargetOptionsFlags MOF;
namespace dsymutil {
static Error copySwiftInterfaces(
const std::map<std::string, std::string> &ParseableSwiftInterfaces,
StringRef Architecture, const LinkOptions &Options) {
std::error_code EC;
SmallString<128> InputPath;
SmallString<128> Path;
sys::path::append(Path, *Options.ResourceDir, "Swift", Architecture);
if ((EC = sys::fs::create_directories(Path.str(), true,
sys::fs::perms::all_all)))
return make_error<StringError>(
"cannot create directory: " + toString(errorCodeToError(EC)), EC);
unsigned BaseLength = Path.size();
for (auto &I : ParseableSwiftInterfaces) {
StringRef ModuleName = I.first;
StringRef InterfaceFile = I.second;
if (!Options.PrependPath.empty()) {
InputPath.clear();
sys::path::append(InputPath, Options.PrependPath, InterfaceFile);
InterfaceFile = InputPath;
}
sys::path::append(Path, ModuleName);
Path.append(".swiftinterface");
if (Options.Verbose)
outs() << "copy parseable Swift interface " << InterfaceFile << " -> "
<< Path.str() << '\n';
// copy_file attempts an APFS clone first, so this should be cheap.
if ((EC = sys::fs::copy_file(InterfaceFile, Path.str())))
warn(Twine("cannot copy parseable Swift interface ") + InterfaceFile +
": " + toString(errorCodeToError(EC)));
Path.resize(BaseLength);
}
return Error::success();
}
/// Report a warning to the user, optionally including information about a
/// specific \p DIE related to the warning.
void DwarfLinkerForBinary::reportWarning(const Twine &Warning,
StringRef Context,
const DWARFDie *DIE) const {
warn(Warning, Context);
if (!Options.Verbose || !DIE)
return;
DIDumpOptions DumpOpts;
DumpOpts.ChildRecurseDepth = 0;
DumpOpts.Verbose = Options.Verbose;
WithColor::note() << " in DIE:\n";
DIE->dump(errs(), 6 /* Indent */, DumpOpts);
}
bool DwarfLinkerForBinary::createStreamer(const Triple &TheTriple,
raw_fd_ostream &OutFile) {
if (Options.NoOutput)
return true;
Streamer = std::make_unique<DwarfStreamer>(
Options.FileType, OutFile, Options.Translator, Options.Minimize,
[&](const Twine &Error, StringRef Context, const DWARFDie *) {
error(Error, Context);
},
[&](const Twine &Warning, StringRef Context, const DWARFDie *) {
warn(Warning, Context);
});
return Streamer->init(TheTriple);
}
ErrorOr<const object::ObjectFile &>
DwarfLinkerForBinary::loadObject(const DebugMapObject &Obj,
const Triple &Triple) {
auto ObjectEntry =
BinHolder.getObjectEntry(Obj.getObjectFilename(), Obj.getTimestamp());
if (!ObjectEntry) {
auto Err = ObjectEntry.takeError();
reportWarning(Twine(Obj.getObjectFilename()) + ": " +
toString(std::move(Err)),
Obj.getObjectFilename());
return errorToErrorCode(std::move(Err));
}
auto Object = ObjectEntry->getObject(Triple);
if (!Object) {
auto Err = Object.takeError();
reportWarning(Twine(Obj.getObjectFilename()) + ": " +
toString(std::move(Err)),
Obj.getObjectFilename());
return errorToErrorCode(std::move(Err));
}
return *Object;
}
static Error remarksErrorHandler(const DebugMapObject &DMO,
DwarfLinkerForBinary &Linker,
std::unique_ptr<FileError> FE) {
bool IsArchive = DMO.getObjectFilename().endswith(")");
// Don't report errors for missing remark files from static
// archives.
if (!IsArchive)
return Error(std::move(FE));
std::string Message = FE->message();
Error E = FE->takeError();
Error NewE = handleErrors(std::move(E), [&](std::unique_ptr<ECError> EC) {
if (EC->convertToErrorCode() != std::errc::no_such_file_or_directory)
return Error(std::move(EC));
Linker.reportWarning(Message, DMO.getObjectFilename());
return Error(Error::success());
});
if (!NewE)
return Error::success();
return createFileError(FE->getFileName(), std::move(NewE));
}
static Error emitRemarks(const LinkOptions &Options, StringRef BinaryPath,
StringRef ArchName, const remarks::RemarkLinker &RL) {
// Make sure we don't create the directories and the file if there is nothing
// to serialize.
if (RL.empty())
return Error::success();
SmallString<128> InputPath;
SmallString<128> Path;
// Create the "Remarks" directory in the "Resources" directory.
sys::path::append(Path, *Options.ResourceDir, "Remarks");
if (std::error_code EC = sys::fs::create_directories(Path.str(), true,
sys::fs::perms::all_all))
return errorCodeToError(EC);
// Append the file name.
// For fat binaries, also append a dash and the architecture name.
sys::path::append(Path, sys::path::filename(BinaryPath));
if (Options.NumDebugMaps > 1) {
// More than one debug map means we have a fat binary.
Path += '-';
Path += ArchName;
}
std::error_code EC;
raw_fd_ostream OS(Options.NoOutput ? "-" : Path.str(), EC, sys::fs::OF_None);
if (EC)
return errorCodeToError(EC);
if (Error E = RL.serialize(OS, Options.RemarksFormat))
return E;
return Error::success();
}
ErrorOr<DwarfFile &>
DwarfLinkerForBinary::loadObject(const DebugMapObject &Obj,
const DebugMap &DebugMap,
remarks::RemarkLinker &RL) {
auto ErrorOrObj = loadObject(Obj, DebugMap.getTriple());
if (ErrorOrObj) {
ContextForLinking.push_back(
std::unique_ptr<DWARFContext>(DWARFContext::create(*ErrorOrObj)));
AddressMapForLinking.push_back(
std::make_unique<AddressManager>(*this, *ErrorOrObj, Obj));
ObjectsForLinking.push_back(std::make_unique<DwarfFile>(
Obj.getObjectFilename(), ContextForLinking.back().get(),
AddressMapForLinking.back().get(),
Obj.empty() ? Obj.getWarnings() : EmptyWarnings));
Error E = RL.link(*ErrorOrObj);
if (Error NewE = handleErrors(
std::move(E), [&](std::unique_ptr<FileError> EC) -> Error {
return remarksErrorHandler(Obj, *this, std::move(EC));
}))
return errorToErrorCode(std::move(NewE));
return *ObjectsForLinking.back();
}
return ErrorOrObj.getError();
}
bool DwarfLinkerForBinary::link(const DebugMap &Map) {
if (!createStreamer(Map.getTriple(), OutFile))
return false;
ObjectsForLinking.clear();
ContextForLinking.clear();
AddressMapForLinking.clear();
DebugMap DebugMap(Map.getTriple(), Map.getBinaryPath());
DWARFLinker GeneralLinker(Streamer.get(), DwarfLinkerClient::Dsymutil);
remarks::RemarkLinker RL;
if (!Options.RemarksPrependPath.empty())
RL.setExternalFilePrependPath(Options.RemarksPrependPath);
GeneralLinker.setObjectPrefixMap(&Options.ObjectPrefixMap);
std::function<StringRef(StringRef)> TranslationLambda = [&](StringRef Input) {
assert(Options.Translator);
return Options.Translator(Input);
};
GeneralLinker.setVerbosity(Options.Verbose);
GeneralLinker.setStatistics(Options.Statistics);
GeneralLinker.setNoOutput(Options.NoOutput);
GeneralLinker.setNoODR(Options.NoODR);
GeneralLinker.setUpdate(Options.Update);
GeneralLinker.setNumThreads(Options.Threads);
GeneralLinker.setAccelTableKind(Options.TheAccelTableKind);
GeneralLinker.setPrependPath(Options.PrependPath);
if (Options.Translator)
GeneralLinker.setStringsTranslator(TranslationLambda);
GeneralLinker.setWarningHandler(
[&](const Twine &Warning, StringRef Context, const DWARFDie *DIE) {
reportWarning(Warning, Context, DIE);
});
GeneralLinker.setErrorHandler(
[&](const Twine &Error, StringRef Context, const DWARFDie *) {
error(Error, Context);
});
GeneralLinker.setObjFileLoader(
[&DebugMap, &RL, this](StringRef ContainerName,
StringRef Path) -> ErrorOr<DwarfFile &> {
auto &Obj = DebugMap.addDebugMapObject(
Path, sys::TimePoint<std::chrono::seconds>(), MachO::N_OSO);
if (auto ErrorOrObj = loadObject(Obj, DebugMap, RL)) {
return *ErrorOrObj;
} else {
// Try and emit more helpful warnings by applying some heuristics.
StringRef ObjFile = ContainerName;
bool IsClangModule = sys::path::extension(Path).equals(".pcm");
bool IsArchive = ObjFile.endswith(")");
if (IsClangModule) {
StringRef ModuleCacheDir = sys::path::parent_path(Path);
if (sys::fs::exists(ModuleCacheDir)) {
// If the module's parent directory exists, we assume that the
// module cache has expired and was pruned by clang. A more
// adventurous dsymutil would invoke clang to rebuild the module
// now.
if (!ModuleCacheHintDisplayed) {
WithColor::note()
<< "The clang module cache may have expired since "
"this object file was built. Rebuilding the "
"object file will rebuild the module cache.\n";
ModuleCacheHintDisplayed = true;
}
} else if (IsArchive) {
// If the module cache directory doesn't exist at all and the
// object file is inside a static library, we assume that the
// static library was built on a different machine. We don't want
// to discourage module debugging for convenience libraries within
// a project though.
if (!ArchiveHintDisplayed) {
WithColor::note()
<< "Linking a static library that was built with "
"-gmodules, but the module cache was not found. "
"Redistributable static libraries should never be "
"built with module debugging enabled. The debug "
"experience will be degraded due to incomplete "
"debug information.\n";
ArchiveHintDisplayed = true;
}
}
}
return ErrorOrObj.getError();
}
llvm_unreachable("Unhandled DebugMap object");
});
GeneralLinker.setSwiftInterfacesMap(&ParseableSwiftInterfaces);
for (const auto &Obj : Map.objects()) {
// N_AST objects (swiftmodule files) should get dumped directly into the
// appropriate DWARF section.
if (Obj->getType() == MachO::N_AST) {
if (Options.Verbose)
outs() << "DEBUG MAP OBJECT: " << Obj->getObjectFilename() << "\n";
StringRef File = Obj->getObjectFilename();
auto ErrorOrMem = MemoryBuffer::getFile(File);
if (!ErrorOrMem) {
warn("Could not open '" + File + "'\n");
continue;
}
sys::fs::file_status Stat;
if (auto Err = sys::fs::status(File, Stat)) {
warn(Err.message());
continue;
}
if (!Options.NoTimestamp) {
// The modification can have sub-second precision so we need to cast
// away the extra precision that's not present in the debug map.
auto ModificationTime =
std::chrono::time_point_cast<std::chrono::seconds>(
Stat.getLastModificationTime());
if (ModificationTime != Obj->getTimestamp()) {
// Not using the helper here as we can easily stream TimePoint<>.
WithColor::warning() << "Timestamp mismatch for " << File << ": "
<< Stat.getLastModificationTime() << " and "
<< sys::TimePoint<>(Obj->getTimestamp()) << "\n";
continue;
}
}
// Copy the module into the .swift_ast section.
if (!Options.NoOutput)
Streamer->emitSwiftAST((*ErrorOrMem)->getBuffer());
continue;
}
if (auto ErrorOrObj = loadObject(*Obj, Map, RL))
GeneralLinker.addObjectFile(*ErrorOrObj);
else {
ObjectsForLinking.push_back(std::make_unique<DwarfFile>(
Obj->getObjectFilename(), nullptr, nullptr,
Obj->empty() ? Obj->getWarnings() : EmptyWarnings));
GeneralLinker.addObjectFile(*ObjectsForLinking.back());
}
}
// link debug info for loaded object files.
GeneralLinker.link();
StringRef ArchName = Map.getTriple().getArchName();
if (Error E = emitRemarks(Options, Map.getBinaryPath(), ArchName, RL))
return error(toString(std::move(E)));
if (Options.NoOutput)
return true;
if (Options.ResourceDir && !ParseableSwiftInterfaces.empty()) {
StringRef ArchName = Triple::getArchTypeName(Map.getTriple().getArch());
if (auto E =
copySwiftInterfaces(ParseableSwiftInterfaces, ArchName, Options))
return error(toString(std::move(E)));
}
if (Map.getTriple().isOSDarwin() && !Map.getBinaryPath().empty() &&
Options.FileType == OutputFileType::Object)
return MachOUtils::generateDsymCompanion(
Options.VFS, Map, Options.Translator,
*Streamer->getAsmPrinter().OutStreamer, OutFile);
Streamer->finish();
return true;
}
static bool isMachOPairedReloc(uint64_t RelocType, uint64_t Arch) {
switch (Arch) {
case Triple::x86:
return RelocType == MachO::GENERIC_RELOC_SECTDIFF ||
RelocType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF;
case Triple::x86_64:
return RelocType == MachO::X86_64_RELOC_SUBTRACTOR;
case Triple::arm:
case Triple::thumb:
return RelocType == MachO::ARM_RELOC_SECTDIFF ||
RelocType == MachO::ARM_RELOC_LOCAL_SECTDIFF ||
RelocType == MachO::ARM_RELOC_HALF ||
RelocType == MachO::ARM_RELOC_HALF_SECTDIFF;
case Triple::aarch64:
return RelocType == MachO::ARM64_RELOC_SUBTRACTOR;
default:
return false;
}
}
/// Iterate over the relocations of the given \p Section and
/// store the ones that correspond to debug map entries into the
/// ValidRelocs array.
void DwarfLinkerForBinary::AddressManager::findValidRelocsMachO(
const object::SectionRef &Section, const object::MachOObjectFile &Obj,
const DebugMapObject &DMO) {
Expected<StringRef> ContentsOrErr = Section.getContents();
if (!ContentsOrErr) {
consumeError(ContentsOrErr.takeError());
Linker.reportWarning("error reading section", DMO.getObjectFilename());
return;
}
DataExtractor Data(*ContentsOrErr, Obj.isLittleEndian(), 0);
bool SkipNext = false;
for (const object::RelocationRef &Reloc : Section.relocations()) {
if (SkipNext) {
SkipNext = false;
continue;
}
object::DataRefImpl RelocDataRef = Reloc.getRawDataRefImpl();
MachO::any_relocation_info MachOReloc = Obj.getRelocation(RelocDataRef);
if (isMachOPairedReloc(Obj.getAnyRelocationType(MachOReloc),
Obj.getArch())) {
SkipNext = true;
Linker.reportWarning("unsupported relocation in debug_info section.",
DMO.getObjectFilename());
continue;
}
unsigned RelocSize = 1 << Obj.getAnyRelocationLength(MachOReloc);
uint64_t Offset64 = Reloc.getOffset();
if ((RelocSize != 4 && RelocSize != 8)) {
Linker.reportWarning("unsupported relocation in debug_info section.",
DMO.getObjectFilename());
continue;
}
uint64_t OffsetCopy = Offset64;
// Mach-o uses REL relocations, the addend is at the relocation offset.
uint64_t Addend = Data.getUnsigned(&OffsetCopy, RelocSize);
uint64_t SymAddress;
int64_t SymOffset;
if (Obj.isRelocationScattered(MachOReloc)) {
// The address of the base symbol for scattered relocations is
// stored in the reloc itself. The actual addend will store the
// base address plus the offset.
SymAddress = Obj.getScatteredRelocationValue(MachOReloc);
SymOffset = int64_t(Addend) - SymAddress;
} else {
SymAddress = Addend;
SymOffset = 0;
}
auto Sym = Reloc.getSymbol();
if (Sym != Obj.symbol_end()) {
Expected<StringRef> SymbolName = Sym->getName();
if (!SymbolName) {
consumeError(SymbolName.takeError());
Linker.reportWarning("error getting relocation symbol name.",
DMO.getObjectFilename());
continue;
}
if (const auto *Mapping = DMO.lookupSymbol(*SymbolName))
ValidRelocs.emplace_back(Offset64, RelocSize, Addend, Mapping);
} else if (const auto *Mapping = DMO.lookupObjectAddress(SymAddress)) {
// Do not store the addend. The addend was the address of the symbol in
// the object file, the address in the binary that is stored in the debug
// map doesn't need to be offset.
ValidRelocs.emplace_back(Offset64, RelocSize, SymOffset, Mapping);
}
}
}
/// Dispatch the valid relocation finding logic to the
/// appropriate handler depending on the object file format.
bool DwarfLinkerForBinary::AddressManager::findValidRelocs(
const object::SectionRef &Section, const object::ObjectFile &Obj,
const DebugMapObject &DMO) {
// Dispatch to the right handler depending on the file type.
if (auto *MachOObj = dyn_cast<object::MachOObjectFile>(&Obj))
findValidRelocsMachO(Section, *MachOObj, DMO);
else
Linker.reportWarning(Twine("unsupported object file type: ") +
Obj.getFileName(),
DMO.getObjectFilename());
if (ValidRelocs.empty())
return false;
// Sort the relocations by offset. We will walk the DIEs linearly in
// the file, this allows us to just keep an index in the relocation
// array that we advance during our walk, rather than resorting to
// some associative container. See DwarfLinkerForBinary::NextValidReloc.
llvm::sort(ValidRelocs);
return true;
}
/// Look for relocations in the debug_info section that match
/// entries in the debug map. These relocations will drive the Dwarf
/// link by indicating which DIEs refer to symbols present in the
/// linked binary.
/// \returns whether there are any valid relocations in the debug info.
bool DwarfLinkerForBinary::AddressManager::findValidRelocsInDebugInfo(
const object::ObjectFile &Obj, const DebugMapObject &DMO) {
// Find the debug_info section.
for (const object::SectionRef &Section : Obj.sections()) {
StringRef SectionName;
if (Expected<StringRef> NameOrErr = Section.getName())
SectionName = *NameOrErr;
else
consumeError(NameOrErr.takeError());
SectionName = SectionName.substr(SectionName.find_first_not_of("._"));
if (SectionName != "debug_info")
continue;
return findValidRelocs(Section, Obj, DMO);
}
return false;
}
/// Checks that there is a relocation against an actual debug
/// map entry between \p StartOffset and \p NextOffset.
///
/// This function must be called with offsets in strictly ascending
/// order because it never looks back at relocations it already 'went past'.
/// \returns true and sets Info.InDebugMap if it is the case.
bool DwarfLinkerForBinary::AddressManager::hasValidRelocationAt(
uint64_t StartOffset, uint64_t EndOffset, CompileUnit::DIEInfo &Info) {
assert(NextValidReloc == 0 ||
StartOffset > ValidRelocs[NextValidReloc - 1].Offset);
if (NextValidReloc >= ValidRelocs.size())
return false;
uint64_t RelocOffset = ValidRelocs[NextValidReloc].Offset;
// We might need to skip some relocs that we didn't consider. For
// example the high_pc of a discarded DIE might contain a reloc that
// is in the list because it actually corresponds to the start of a
// function that is in the debug map.
while (RelocOffset < StartOffset && NextValidReloc < ValidRelocs.size() - 1)
RelocOffset = ValidRelocs[++NextValidReloc].Offset;
if (RelocOffset < StartOffset || RelocOffset >= EndOffset)
return false;
const auto &ValidReloc = ValidRelocs[NextValidReloc++];
const auto &Mapping = ValidReloc.Mapping->getValue();
const uint64_t BinaryAddress = Mapping.BinaryAddress;
const uint64_t ObjectAddress = Mapping.ObjectAddress
? uint64_t(*Mapping.ObjectAddress)
: std::numeric_limits<uint64_t>::max();
if (Linker.Options.Verbose)
outs() << "Found valid debug map entry: " << ValidReloc.Mapping->getKey()
<< "\t"
<< format("0x%016" PRIx64 " => 0x%016" PRIx64 "\n", ObjectAddress,
BinaryAddress);
Info.AddrAdjust = BinaryAddress + ValidReloc.Addend;
if (Mapping.ObjectAddress)
Info.AddrAdjust -= ObjectAddress;
Info.InDebugMap = true;
return true;
}
/// Apply the valid relocations found by findValidRelocs() to
/// the buffer \p Data, taking into account that Data is at \p BaseOffset
/// in the debug_info section.
///
/// Like for findValidRelocs(), this function must be called with
/// monotonic \p BaseOffset values.
///
/// \returns whether any reloc has been applied.
bool DwarfLinkerForBinary::AddressManager::applyValidRelocs(
MutableArrayRef<char> Data, uint64_t BaseOffset, bool IsLittleEndian) {
assert(areRelocationsResolved());
assert((NextValidReloc == 0 ||
BaseOffset > ValidRelocs[NextValidReloc - 1].Offset) &&
"BaseOffset should only be increasing.");
if (NextValidReloc >= ValidRelocs.size())
return false;
// Skip relocs that haven't been applied.
while (NextValidReloc < ValidRelocs.size() &&
ValidRelocs[NextValidReloc].Offset < BaseOffset)
++NextValidReloc;
bool Applied = false;
uint64_t EndOffset = BaseOffset + Data.size();
while (NextValidReloc < ValidRelocs.size() &&
ValidRelocs[NextValidReloc].Offset >= BaseOffset &&
ValidRelocs[NextValidReloc].Offset < EndOffset) {
const auto &ValidReloc = ValidRelocs[NextValidReloc++];
assert(ValidReloc.Offset - BaseOffset < Data.size());
assert(ValidReloc.Offset - BaseOffset + ValidReloc.Size <= Data.size());
char Buf[8];
uint64_t Value = ValidReloc.Mapping->getValue().BinaryAddress;
Value += ValidReloc.Addend;
for (unsigned I = 0; I != ValidReloc.Size; ++I) {
unsigned Index = IsLittleEndian ? I : (ValidReloc.Size - I - 1);
Buf[I] = uint8_t(Value >> (Index * 8));
}
assert(ValidReloc.Size <= sizeof(Buf));
memcpy(&Data[ValidReloc.Offset - BaseOffset], Buf, ValidReloc.Size);
Applied = true;
}
return Applied;
}
bool linkDwarf(raw_fd_ostream &OutFile, BinaryHolder &BinHolder,
const DebugMap &DM, LinkOptions Options) {
DwarfLinkerForBinary Linker(OutFile, BinHolder, std::move(Options));
return Linker.link(DM);
}
} // namespace dsymutil
} // namespace llvm
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