llvm/tools/llvm-dwp/llvm-dwp.cpp
David Blaikie ce4a723916 [llvm-dwp] Sink debug_types.dwo emission into the code parsing the type signatures (NFC)
This is a preliminary change towards deduplicating type units based on
their signatures. Next change will skip emission of types when their
signature has already been seen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@255154 91177308-0d34-0410-b5e6-96231b3b80d8
2015-12-09 21:02:33 +00:00

412 lines
14 KiB
C++

#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCObjectFileInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSectionELF.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Options.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetMachine.h"
#include <list>
#include <memory>
#include <unordered_set>
using namespace llvm;
using namespace llvm::object;
using namespace cl;
OptionCategory DwpCategory("Specific Options");
static list<std::string> InputFiles(Positional, OneOrMore,
desc("<input files>"), cat(DwpCategory));
static opt<std::string> OutputFilename(Required, "o",
desc("Specify the output file."),
value_desc("filename"),
cat(DwpCategory));
static int error(const Twine &Error, const Twine &Context) {
errs() << Twine("while processing ") + Context + ":\n";
errs() << Twine("error: ") + Error + "\n";
return 1;
}
static std::error_code
writeStringsAndOffsets(MCStreamer &Out, StringMap<uint32_t> &Strings,
uint32_t &StringOffset, MCSection *StrSection,
MCSection *StrOffsetSection, StringRef CurStrSection,
StringRef CurStrOffsetSection) {
// Could possibly produce an error or warning if one of these was non-null but
// the other was null.
if (CurStrSection.empty() || CurStrOffsetSection.empty())
return std::error_code();
DenseMap<uint32_t, uint32_t> OffsetRemapping;
DataExtractor Data(CurStrSection, true, 0);
uint32_t LocalOffset = 0;
uint32_t PrevOffset = 0;
while (const char *s = Data.getCStr(&LocalOffset)) {
StringRef Str(s, LocalOffset - PrevOffset - 1);
auto Pair = Strings.insert(std::make_pair(Str, StringOffset));
if (Pair.second) {
Out.SwitchSection(StrSection);
Out.EmitBytes(
StringRef(Pair.first->getKeyData(), Pair.first->getKeyLength() + 1));
StringOffset += Str.size() + 1;
}
OffsetRemapping[PrevOffset] = Pair.first->second;
PrevOffset = LocalOffset;
}
Data = DataExtractor(CurStrOffsetSection, true, 0);
Out.SwitchSection(StrOffsetSection);
uint32_t Offset = 0;
uint64_t Size = CurStrOffsetSection.size();
while (Offset < Size) {
auto OldOffset = Data.getU32(&Offset);
auto NewOffset = OffsetRemapping[OldOffset];
Out.EmitIntValue(NewOffset, 4);
}
return std::error_code();
}
static uint32_t getCUAbbrev(StringRef Abbrev, uint64_t AbbrCode) {
uint64_t CurCode;
uint32_t Offset = 0;
DataExtractor AbbrevData(Abbrev, true, 0);
while ((CurCode = AbbrevData.getULEB128(&Offset)) != AbbrCode) {
// Tag
AbbrevData.getULEB128(&Offset);
// DW_CHILDREN
AbbrevData.getU8(&Offset);
// Attributes
while (AbbrevData.getULEB128(&Offset) | AbbrevData.getULEB128(&Offset))
;
}
return Offset;
}
static uint64_t getCUSignature(StringRef Abbrev, StringRef Info) {
uint32_t Offset = 0;
DataExtractor InfoData(Info, true, 0);
InfoData.getU32(&Offset); // Length
uint16_t Version = InfoData.getU16(&Offset);
InfoData.getU32(&Offset); // Abbrev offset (should be zero)
uint8_t AddrSize = InfoData.getU8(&Offset);
uint32_t AbbrCode = InfoData.getULEB128(&Offset);
DataExtractor AbbrevData(Abbrev, true, 0);
uint32_t AbbrevOffset = getCUAbbrev(Abbrev, AbbrCode);
uint64_t Tag = AbbrevData.getULEB128(&AbbrevOffset);
(void)Tag;
// FIXME: Real error handling
assert(Tag == dwarf::DW_TAG_compile_unit);
// DW_CHILDREN
AbbrevData.getU8(&AbbrevOffset);
uint32_t Name;
uint32_t Form;
while ((Name = AbbrevData.getULEB128(&AbbrevOffset)) |
(Form = AbbrevData.getULEB128(&AbbrevOffset)) &&
Name != dwarf::DW_AT_GNU_dwo_id) {
DWARFFormValue::skipValue(Form, InfoData, &Offset, Version, AddrSize);
}
// FIXME: Real error handling
assert(Name == dwarf::DW_AT_GNU_dwo_id);
return InfoData.getU64(&Offset);
}
struct UnitIndexEntry {
uint64_t Signature;
DWARFUnitIndex::Entry::SectionContribution Contributions[8];
};
static void addAllTypes(MCStreamer &Out,
std::vector<UnitIndexEntry> &TypeIndexEntries,
MCSection *OutputTypes, StringRef Types,
const UnitIndexEntry &CUEntry, uint32_t &TypesOffset) {
if (Types.empty())
return;
Out.SwitchSection(OutputTypes);
uint32_t Offset = 0;
DataExtractor Data(Types, true, 0);
while (Data.isValidOffset(Offset)) {
TypeIndexEntries.push_back(CUEntry);
auto &Entry = TypeIndexEntries.back();
// Zero out the debug_info contribution
Entry.Contributions[0] = {};
auto &C = Entry.Contributions[DW_SECT_TYPES - DW_SECT_INFO];
C.Offset = TypesOffset + Offset;
auto PrevOffset = Offset;
// Length of the unit, including the 4 byte length field.
C.Length = Data.getU32(&Offset) + 4;
Out.EmitBytes(Types.substr(Offset - 4, C.Length));
TypesOffset += C.Length;
Data.getU16(&Offset); // Version
Data.getU32(&Offset); // Abbrev offset
Data.getU8(&Offset); // Address size
Entry.Signature = Data.getU64(&Offset);
Offset = PrevOffset + C.Length;
}
}
static void
writeIndexTable(MCStreamer &Out, ArrayRef<unsigned> ContributionOffsets,
ArrayRef<UnitIndexEntry> IndexEntries,
uint32_t DWARFUnitIndex::Entry::SectionContribution::*Field) {
for (const auto &E : IndexEntries)
for (size_t i = 0; i != array_lengthof(E.Contributions); ++i)
if (ContributionOffsets[i])
Out.EmitIntValue(E.Contributions[i].*Field, 4);
}
static void writeIndex(MCStreamer &Out, MCSection *Section,
ArrayRef<unsigned> ContributionOffsets,
ArrayRef<UnitIndexEntry> IndexEntries) {
unsigned Columns = 0;
for (auto &C : ContributionOffsets)
if (C)
++Columns;
std::vector<unsigned> Buckets(NextPowerOf2(3 * IndexEntries.size() / 2));
uint64_t Mask = Buckets.size() - 1;
for (size_t i = 0; i != IndexEntries.size(); ++i) {
auto S = IndexEntries[i].Signature;
auto H = S & Mask;
while (Buckets[H]) {
assert(S != IndexEntries[Buckets[H] - 1].Signature &&
"Duplicate type unit");
H += ((S >> 32) & Mask) | 1;
}
Buckets[H] = i + 1;
}
Out.SwitchSection(Section);
Out.EmitIntValue(2, 4); // Version
Out.EmitIntValue(Columns, 4); // Columns
Out.EmitIntValue(IndexEntries.size(), 4); // Num Units
Out.EmitIntValue(Buckets.size(), 4); // Num Buckets
// Write the signatures.
for (const auto &I : Buckets)
Out.EmitIntValue(I ? IndexEntries[I - 1].Signature : 0, 8);
// Write the indexes.
for (const auto &I : Buckets)
Out.EmitIntValue(I, 4);
// Write the column headers (which sections will appear in the table)
for (size_t i = 0; i != ContributionOffsets.size(); ++i)
if (ContributionOffsets[i])
Out.EmitIntValue(i + DW_SECT_INFO, 4);
// Write the offsets.
writeIndexTable(Out, ContributionOffsets, IndexEntries,
&DWARFUnitIndex::Entry::SectionContribution::Offset);
// Write the lengths.
writeIndexTable(Out, ContributionOffsets, IndexEntries,
&DWARFUnitIndex::Entry::SectionContribution::Length);
}
static std::error_code write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
const auto &MCOFI = *Out.getContext().getObjectFileInfo();
MCSection *const StrSection = MCOFI.getDwarfStrDWOSection();
MCSection *const StrOffsetSection = MCOFI.getDwarfStrOffDWOSection();
MCSection *const TypesSection = MCOFI.getDwarfTypesDWOSection();
const StringMap<std::pair<MCSection *, DWARFSectionKind>> KnownSections = {
{"debug_info.dwo", {MCOFI.getDwarfInfoDWOSection(), DW_SECT_INFO}},
{"debug_types.dwo", {MCOFI.getDwarfTypesDWOSection(), DW_SECT_TYPES}},
{"debug_str_offsets.dwo", {StrOffsetSection, DW_SECT_STR_OFFSETS}},
{"debug_str.dwo", {StrSection, static_cast<DWARFSectionKind>(0)}},
{"debug_loc.dwo", {MCOFI.getDwarfLocDWOSection(), DW_SECT_LOC}},
{"debug_line.dwo", {MCOFI.getDwarfLineDWOSection(), DW_SECT_LINE}},
{"debug_abbrev.dwo", {MCOFI.getDwarfAbbrevDWOSection(), DW_SECT_ABBREV}}};
std::vector<UnitIndexEntry> IndexEntries;
std::vector<UnitIndexEntry> TypeIndexEntries;
StringMap<uint32_t> Strings;
uint32_t StringOffset = 0;
uint32_t ContributionOffsets[8] = {};
for (const auto &Input : Inputs) {
auto ErrOrObj = object::ObjectFile::createObjectFile(Input);
if (!ErrOrObj)
return ErrOrObj.getError();
IndexEntries.emplace_back();
UnitIndexEntry &CurEntry = IndexEntries.back();
StringRef CurStrSection;
StringRef CurStrOffsetSection;
StringRef CurTypesSection;
StringRef InfoSection;
StringRef AbbrevSection;
for (const auto &Section : ErrOrObj->getBinary()->sections()) {
StringRef Name;
if (std::error_code Err = Section.getName(Name))
return Err;
auto SectionPair =
KnownSections.find(Name.substr(Name.find_first_not_of("._")));
if (SectionPair == KnownSections.end())
continue;
StringRef Contents;
if (auto Err = Section.getContents(Contents))
return Err;
if (DWARFSectionKind Kind = SectionPair->second.second) {
auto Index = Kind - DW_SECT_INFO;
if (Kind != DW_SECT_TYPES) {
CurEntry.Contributions[Index].Offset = ContributionOffsets[Index];
ContributionOffsets[Index] +=
(CurEntry.Contributions[Index].Length = Contents.size());
}
switch (Kind) {
case DW_SECT_INFO:
InfoSection = Contents;
break;
case DW_SECT_ABBREV:
AbbrevSection = Contents;
break;
default:
break;
}
}
MCSection *OutSection = SectionPair->second.first;
if (OutSection == StrOffsetSection)
CurStrOffsetSection = Contents;
else if (OutSection == StrSection)
CurStrSection = Contents;
else if (OutSection == TypesSection)
CurTypesSection = Contents;
else {
Out.SwitchSection(OutSection);
Out.EmitBytes(Contents);
}
}
assert(!AbbrevSection.empty());
assert(!InfoSection.empty());
CurEntry.Signature = getCUSignature(AbbrevSection, InfoSection);
addAllTypes(Out, TypeIndexEntries, TypesSection, CurTypesSection, CurEntry,
ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO]);
if (auto Err = writeStringsAndOffsets(Out, Strings, StringOffset,
StrSection, StrOffsetSection,
CurStrSection, CurStrOffsetSection))
return Err;
}
if (!TypeIndexEntries.empty()) {
// Lie about there being no info contributions so the TU index only includes
// the type unit contribution
ContributionOffsets[0] = 0;
writeIndex(Out, MCOFI.getDwarfTUIndexSection(), ContributionOffsets,
TypeIndexEntries);
}
// Lie about the type contribution
ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO] = 0;
// Unlie about the info contribution
ContributionOffsets[0] = 1;
writeIndex(Out, MCOFI.getDwarfCUIndexSection(), ContributionOffsets,
IndexEntries);
return std::error_code();
}
int main(int argc, char **argv) {
ParseCommandLineOptions(argc, argv, "merge split dwarf (.dwo) files");
llvm::InitializeAllTargetInfos();
llvm::InitializeAllTargetMCs();
llvm::InitializeAllTargets();
llvm::InitializeAllAsmPrinters();
std::string ErrorStr;
StringRef Context = "dwarf streamer init";
Triple TheTriple("x86_64-linux-gnu");
// Get the target.
const Target *TheTarget =
TargetRegistry::lookupTarget("", TheTriple, ErrorStr);
if (!TheTarget)
return error(ErrorStr, Context);
std::string TripleName = TheTriple.getTriple();
// Create all the MC Objects.
std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
if (!MRI)
return error(Twine("no register info for target ") + TripleName, Context);
std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI, TripleName));
if (!MAI)
return error("no asm info for target " + TripleName, Context);
MCObjectFileInfo MOFI;
MCContext MC(MAI.get(), MRI.get(), &MOFI);
MOFI.InitMCObjectFileInfo(TheTriple, Reloc::Default, CodeModel::Default, MC);
auto MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "");
if (!MAB)
return error("no asm backend for target " + TripleName, Context);
std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
if (!MII)
return error("no instr info info for target " + TripleName, Context);
std::unique_ptr<MCSubtargetInfo> MSTI(
TheTarget->createMCSubtargetInfo(TripleName, "", ""));
if (!MSTI)
return error("no subtarget info for target " + TripleName, Context);
MCCodeEmitter *MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, MC);
if (!MCE)
return error("no code emitter for target " + TripleName, Context);
// Create the output file.
std::error_code EC;
raw_fd_ostream OutFile(OutputFilename, EC, sys::fs::F_None);
if (EC)
return error(Twine(OutputFilename) + ": " + EC.message(), Context);
std::unique_ptr<MCStreamer> MS(TheTarget->createMCObjectStreamer(
TheTriple, MC, *MAB, OutFile, MCE, *MSTI, false,
/*DWARFMustBeAtTheEnd*/ false));
if (!MS)
return error("no object streamer for target " + TripleName, Context);
if (auto Err = write(*MS, InputFiles))
return error(Err.message(), "Writing DWP file");
MS->Finish();
}