llvm-project/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp

1322 lines
47 KiB
C++

//===- DWARFContext.cpp ---------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugAranges.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugLoc.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugMacro.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugPubTable.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugRangeList.h"
#include "llvm/DebugInfo/DWARF/DWARFDie.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFGdbIndex.h"
#include "llvm/DebugInfo/DWARF/DWARFSection.h"
#include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
#include "llvm/DebugInfo/DWARF/DWARFVerifier.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/Object/Decompressor.h"
#include "llvm/Object/MachO.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Object/RelocVisitor.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cstdint>
#include <map>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace llvm;
using namespace dwarf;
using namespace object;
#define DEBUG_TYPE "dwarf"
using DWARFLineTable = DWARFDebugLine::LineTable;
using FileLineInfoKind = DILineInfoSpecifier::FileLineInfoKind;
using FunctionNameKind = DILineInfoSpecifier::FunctionNameKind;
DWARFContext::DWARFContext(std::unique_ptr<const DWARFObject> DObj,
std::string DWPName)
: DIContext(CK_DWARF), DWPName(std::move(DWPName)), DObj(std::move(DObj)) {}
DWARFContext::~DWARFContext() = default;
static void dumpAccelSection(raw_ostream &OS, StringRef Name,
const DWARFObject &Obj,
const DWARFSection &Section,
StringRef StringSection, bool LittleEndian) {
DWARFDataExtractor AccelSection(Obj, Section, LittleEndian, 0);
DataExtractor StrData(StringSection, LittleEndian, 0);
OS << "\n." << Name << " contents:\n";
DWARFAcceleratorTable Accel(AccelSection, StrData);
if (!Accel.extract())
return;
Accel.dump(OS);
}
static void
dumpDWARFv5StringOffsetsSection(raw_ostream &OS, StringRef SectionName,
const DWARFObject &Obj,
const DWARFSection &StringOffsetsSection,
StringRef StringSection, bool LittleEndian) {
DWARFDataExtractor StrOffsetExt(Obj, StringOffsetsSection, LittleEndian, 0);
uint32_t Offset = 0;
uint64_t SectionSize = StringOffsetsSection.Data.size();
while (Offset < SectionSize) {
unsigned Version = 0;
DwarfFormat Format = DWARF32;
unsigned EntrySize = 4;
// Perform validation and extract the segment size from the header.
if (!StrOffsetExt.isValidOffsetForDataOfSize(Offset, 4)) {
OS << "error: invalid contribution to string offsets table in section ."
<< SectionName << ".\n";
return;
}
uint32_t ContributionStart = Offset;
uint64_t ContributionSize = StrOffsetExt.getU32(&Offset);
// A contribution size of 0xffffffff indicates DWARF64, with the actual size
// in the following 8 bytes. Otherwise, the DWARF standard mandates that
// the contribution size must be at most 0xfffffff0.
if (ContributionSize == 0xffffffff) {
if (!StrOffsetExt.isValidOffsetForDataOfSize(Offset, 8)) {
OS << "error: invalid contribution to string offsets table in section ."
<< SectionName << ".\n";
return;
}
Format = DWARF64;
EntrySize = 8;
ContributionSize = StrOffsetExt.getU64(&Offset);
} else if (ContributionSize > 0xfffffff0) {
OS << "error: invalid contribution to string offsets table in section ."
<< SectionName << ".\n";
return;
}
// We must ensure that we don't read a partial record at the end, so we
// validate for a multiple of EntrySize. Also, we're expecting a version
// number and padding, which adds an additional 4 bytes.
uint64_t ValidationSize =
4 + ((ContributionSize + EntrySize - 1) & (-(uint64_t)EntrySize));
if (!StrOffsetExt.isValidOffsetForDataOfSize(Offset, ValidationSize)) {
OS << "error: contribution to string offsets table in section ."
<< SectionName << " has invalid length.\n";
return;
}
Version = StrOffsetExt.getU16(&Offset);
Offset += 2;
OS << format("0x%8.8x: ", ContributionStart);
OS << "Contribution size = " << ContributionSize
<< ", Version = " << Version << "\n";
uint32_t ContributionBase = Offset;
DataExtractor StrData(StringSection, LittleEndian, 0);
while (Offset - ContributionBase < ContributionSize) {
OS << format("0x%8.8x: ", Offset);
// FIXME: We can only extract strings in DWARF32 format at the moment.
uint64_t StringOffset =
StrOffsetExt.getRelocatedValue(EntrySize, &Offset);
if (Format == DWARF32) {
uint32_t StringOffset32 = (uint32_t)StringOffset;
OS << format("%8.8x ", StringOffset32);
const char *S = StrData.getCStr(&StringOffset32);
if (S)
OS << format("\"%s\"", S);
} else
OS << format("%16.16" PRIx64 " ", StringOffset);
OS << "\n";
}
}
}
// Dump a DWARF string offsets section. This may be a DWARF v5 formatted
// string offsets section, where each compile or type unit contributes a
// number of entries (string offsets), with each contribution preceded by
// a header containing size and version number. Alternatively, it may be a
// monolithic series of string offsets, as generated by the pre-DWARF v5
// implementation of split DWARF.
static void dumpStringOffsetsSection(raw_ostream &OS, StringRef SectionName,
const DWARFObject &Obj,
const DWARFSection &StringOffsetsSection,
StringRef StringSection, bool LittleEndian,
unsigned MaxVersion) {
if (StringOffsetsSection.Data.empty())
return;
OS << "\n." << SectionName << " contents:\n";
// If we have at least one (compile or type) unit with DWARF v5 or greater,
// we assume that the section is formatted like a DWARF v5 string offsets
// section.
if (MaxVersion >= 5)
dumpDWARFv5StringOffsetsSection(OS, SectionName, Obj, StringOffsetsSection,
StringSection, LittleEndian);
else {
DataExtractor strOffsetExt(StringOffsetsSection.Data, LittleEndian, 0);
uint32_t offset = 0;
uint64_t size = StringOffsetsSection.Data.size();
// Ensure that size is a multiple of the size of an entry.
if (size & ((uint64_t)(sizeof(uint32_t) - 1))) {
OS << "error: size of ." << SectionName << " is not a multiple of "
<< sizeof(uint32_t) << ".\n";
size &= -(uint64_t)sizeof(uint32_t);
}
DataExtractor StrData(StringSection, LittleEndian, 0);
while (offset < size) {
OS << format("0x%8.8x: ", offset);
uint32_t StringOffset = strOffsetExt.getU32(&offset);
OS << format("%8.8x ", StringOffset);
const char *S = StrData.getCStr(&StringOffset);
if (S)
OS << format("\"%s\"", S);
OS << "\n";
}
}
}
void DWARFContext::dump(raw_ostream &OS, DIDumpOptions DumpOpts) {
DIDumpType DumpType = DumpOpts.DumpType;
bool DumpEH = DumpOpts.DumpEH;
bool SummarizeTypes = DumpOpts.SummarizeTypes;
if (DumpType == DIDT_All || DumpType == DIDT_Abbrev) {
OS << ".debug_abbrev contents:\n";
getDebugAbbrev()->dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_AbbrevDwo)
if (const DWARFDebugAbbrev *D = getDebugAbbrevDWO()) {
OS << "\n.debug_abbrev.dwo contents:\n";
D->dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_Info) {
OS << "\n.debug_info contents:\n";
for (const auto &CU : compile_units())
CU->dump(OS, DumpOpts);
}
if ((DumpType == DIDT_All || DumpType == DIDT_InfoDwo) &&
getNumDWOCompileUnits()) {
OS << "\n.debug_info.dwo contents:\n";
for (const auto &DWOCU : dwo_compile_units())
DWOCU->dump(OS, DumpOpts);
}
if ((DumpType == DIDT_All || DumpType == DIDT_Types) && getNumTypeUnits()) {
OS << "\n.debug_types contents:\n";
for (const auto &TUS : type_unit_sections())
for (const auto &TU : TUS)
TU->dump(OS, SummarizeTypes);
}
if ((DumpType == DIDT_All || DumpType == DIDT_TypesDwo) &&
getNumDWOTypeUnits()) {
OS << "\n.debug_types.dwo contents:\n";
for (const auto &DWOTUS : dwo_type_unit_sections())
for (const auto &DWOTU : DWOTUS)
DWOTU->dump(OS, SummarizeTypes);
}
if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
OS << "\n.debug_loc contents:\n";
getDebugLoc()->dump(OS, getRegisterInfo());
}
if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) {
OS << "\n.debug_loc.dwo contents:\n";
getDebugLocDWO()->dump(OS, getRegisterInfo());
}
if (DumpType == DIDT_All || DumpType == DIDT_Frames) {
OS << "\n.debug_frame contents:\n";
getDebugFrame()->dump(OS);
if (DumpEH) {
OS << "\n.eh_frame contents:\n";
getEHFrame()->dump(OS);
}
}
if (DumpType == DIDT_All || DumpType == DIDT_Macro) {
OS << "\n.debug_macinfo contents:\n";
getDebugMacro()->dump(OS);
}
uint32_t offset = 0;
if (DumpType == DIDT_All || DumpType == DIDT_Aranges) {
OS << "\n.debug_aranges contents:\n";
DataExtractor arangesData(DObj->getARangeSection(), isLittleEndian(), 0);
DWARFDebugArangeSet set;
while (set.extract(arangesData, &offset))
set.dump(OS);
}
uint8_t savedAddressByteSize = 0;
if (DumpType == DIDT_All || DumpType == DIDT_Line) {
OS << "\n.debug_line contents:\n";
for (const auto &CU : compile_units()) {
savedAddressByteSize = CU->getAddressByteSize();
auto CUDIE = CU->getUnitDIE();
if (!CUDIE)
continue;
if (auto StmtOffset = toSectionOffset(CUDIE.find(DW_AT_stmt_list))) {
DWARFDataExtractor lineData(*DObj, DObj->getLineSection(),
isLittleEndian(), savedAddressByteSize);
DWARFDebugLine::LineTable LineTable;
uint32_t Offset = *StmtOffset;
LineTable.parse(lineData, &Offset);
LineTable.dump(OS);
}
}
}
if (DumpType == DIDT_All || DumpType == DIDT_CUIndex) {
OS << "\n.debug_cu_index contents:\n";
getCUIndex().dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_TUIndex) {
OS << "\n.debug_tu_index contents:\n";
getTUIndex().dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_LineDwo) {
OS << "\n.debug_line.dwo contents:\n";
unsigned stmtOffset = 0;
DWARFDataExtractor lineData(*DObj, DObj->getLineDWOSection(),
isLittleEndian(), savedAddressByteSize);
DWARFDebugLine::LineTable LineTable;
while (LineTable.Prologue.parse(lineData, &stmtOffset)) {
LineTable.dump(OS);
LineTable.clear();
}
}
if (DumpType == DIDT_All || DumpType == DIDT_Str) {
OS << "\n.debug_str contents:\n";
DataExtractor strData(DObj->getStringSection(), isLittleEndian(), 0);
offset = 0;
uint32_t strOffset = 0;
while (const char *s = strData.getCStr(&offset)) {
OS << format("0x%8.8x: \"%s\"\n", strOffset, s);
strOffset = offset;
}
}
if ((DumpType == DIDT_All || DumpType == DIDT_StrDwo) &&
!DObj->getStringDWOSection().empty()) {
OS << "\n.debug_str.dwo contents:\n";
DataExtractor strDWOData(DObj->getStringDWOSection(), isLittleEndian(), 0);
offset = 0;
uint32_t strDWOOffset = 0;
while (const char *s = strDWOData.getCStr(&offset)) {
OS << format("0x%8.8x: \"%s\"\n", strDWOOffset, s);
strDWOOffset = offset;
}
}
if (DumpType == DIDT_All || DumpType == DIDT_Ranges) {
OS << "\n.debug_ranges contents:\n";
// In fact, different compile units may have different address byte
// sizes, but for simplicity we just use the address byte size of the last
// compile unit (there is no easy and fast way to associate address range
// list and the compile unit it describes).
DWARFDataExtractor rangesData(*DObj, DObj->getRangeSection(),
isLittleEndian(), savedAddressByteSize);
offset = 0;
DWARFDebugRangeList rangeList;
while (rangeList.extract(rangesData, &offset))
rangeList.dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
DWARFDebugPubTable(DObj->getPubNamesSection(), isLittleEndian(), false)
.dump("debug_pubnames", OS);
if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
DWARFDebugPubTable(DObj->getPubTypesSection(), isLittleEndian(), false)
.dump("debug_pubtypes", OS);
if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
DWARFDebugPubTable(DObj->getGnuPubNamesSection(), isLittleEndian(),
true /* GnuStyle */)
.dump("debug_gnu_pubnames", OS);
if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
DWARFDebugPubTable(DObj->getGnuPubTypesSection(), isLittleEndian(),
true /* GnuStyle */)
.dump("debug_gnu_pubtypes", OS);
if (DumpType == DIDT_All || DumpType == DIDT_StrOffsets)
dumpStringOffsetsSection(
OS, "debug_str_offsets", *DObj, DObj->getStringOffsetSection(),
DObj->getStringSection(), isLittleEndian(), getMaxVersion());
if (DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) {
dumpStringOffsetsSection(
OS, "debug_str_offsets.dwo", *DObj, DObj->getStringOffsetDWOSection(),
DObj->getStringDWOSection(), isLittleEndian(), getMaxVersion());
}
if ((DumpType == DIDT_All || DumpType == DIDT_GdbIndex) &&
!DObj->getGdbIndexSection().empty()) {
OS << "\n.gnu_index contents:\n";
getGdbIndex().dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
dumpAccelSection(OS, "apple_names", *DObj, DObj->getAppleNamesSection(),
DObj->getStringSection(), isLittleEndian());
if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
dumpAccelSection(OS, "apple_types", *DObj, DObj->getAppleTypesSection(),
DObj->getStringSection(), isLittleEndian());
if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
dumpAccelSection(OS, "apple_namespaces", *DObj,
DObj->getAppleNamespacesSection(),
DObj->getStringSection(), isLittleEndian());
if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
dumpAccelSection(OS, "apple_objc", *DObj, DObj->getAppleObjCSection(),
DObj->getStringSection(), isLittleEndian());
}
DWARFCompileUnit *DWARFContext::getDWOCompileUnitForHash(uint64_t Hash) {
parseDWOCompileUnits();
if (const auto &CUI = getCUIndex()) {
if (const auto *R = CUI.getFromHash(Hash))
if (auto CUOff = R->getOffset(DW_SECT_INFO))
return DWOCUs.getUnitForOffset(CUOff->Offset);
return nullptr;
}
// If there's no index, just search through the CUs in the DWO - there's
// probably only one unless this is something like LTO - though an in-process
// built/cached lookup table could be used in that case to improve repeated
// lookups of different CUs in the DWO.
for (const auto &DWOCU : dwo_compile_units())
if (DWOCU->getDWOId() == Hash)
return DWOCU.get();
return nullptr;
}
DWARFDie DWARFContext::getDIEForOffset(uint32_t Offset) {
parseCompileUnits();
if (auto *CU = CUs.getUnitForOffset(Offset))
return CU->getDIEForOffset(Offset);
return DWARFDie();
}
bool DWARFContext::verify(raw_ostream &OS, DIDumpType DumpType) {
bool Success = true;
DWARFVerifier verifier(OS, *this);
Success &= verifier.handleDebugAbbrev();
if (DumpType == DIDT_All || DumpType == DIDT_Info)
Success &= verifier.handleDebugInfo();
if (DumpType == DIDT_All || DumpType == DIDT_Line)
Success &= verifier.handleDebugLine();
Success &= verifier.handleAccelTables();
return Success;
}
const DWARFUnitIndex &DWARFContext::getCUIndex() {
if (CUIndex)
return *CUIndex;
DataExtractor CUIndexData(DObj->getCUIndexSection(), isLittleEndian(), 0);
CUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_INFO);
CUIndex->parse(CUIndexData);
return *CUIndex;
}
const DWARFUnitIndex &DWARFContext::getTUIndex() {
if (TUIndex)
return *TUIndex;
DataExtractor TUIndexData(DObj->getTUIndexSection(), isLittleEndian(), 0);
TUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_TYPES);
TUIndex->parse(TUIndexData);
return *TUIndex;
}
DWARFGdbIndex &DWARFContext::getGdbIndex() {
if (GdbIndex)
return *GdbIndex;
DataExtractor GdbIndexData(DObj->getGdbIndexSection(), true /*LE*/, 0);
GdbIndex = llvm::make_unique<DWARFGdbIndex>();
GdbIndex->parse(GdbIndexData);
return *GdbIndex;
}
const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
if (Abbrev)
return Abbrev.get();
DataExtractor abbrData(DObj->getAbbrevSection(), isLittleEndian(), 0);
Abbrev.reset(new DWARFDebugAbbrev());
Abbrev->extract(abbrData);
return Abbrev.get();
}
const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
if (AbbrevDWO)
return AbbrevDWO.get();
DataExtractor abbrData(DObj->getAbbrevDWOSection(), isLittleEndian(), 0);
AbbrevDWO.reset(new DWARFDebugAbbrev());
AbbrevDWO->extract(abbrData);
return AbbrevDWO.get();
}
const DWARFDebugLoc *DWARFContext::getDebugLoc() {
if (Loc)
return Loc.get();
Loc.reset(new DWARFDebugLoc);
// assume all compile units have the same address byte size
if (getNumCompileUnits()) {
DWARFDataExtractor LocData(*DObj, DObj->getLocSection(), isLittleEndian(),
getCompileUnitAtIndex(0)->getAddressByteSize());
Loc->parse(LocData);
}
return Loc.get();
}
const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
if (LocDWO)
return LocDWO.get();
DataExtractor LocData(DObj->getLocDWOSection().Data, isLittleEndian(), 0);
LocDWO.reset(new DWARFDebugLocDWO());
LocDWO->parse(LocData);
return LocDWO.get();
}
const DWARFDebugAranges *DWARFContext::getDebugAranges() {
if (Aranges)
return Aranges.get();
Aranges.reset(new DWARFDebugAranges());
Aranges->generate(this);
return Aranges.get();
}
const DWARFDebugFrame *DWARFContext::getDebugFrame() {
if (DebugFrame)
return DebugFrame.get();
// There's a "bug" in the DWARFv3 standard with respect to the target address
// size within debug frame sections. While DWARF is supposed to be independent
// of its container, FDEs have fields with size being "target address size",
// which isn't specified in DWARF in general. It's only specified for CUs, but
// .eh_frame can appear without a .debug_info section. Follow the example of
// other tools (libdwarf) and extract this from the container (ObjectFile
// provides this information). This problem is fixed in DWARFv4
// See this dwarf-discuss discussion for more details:
// http://lists.dwarfstd.org/htdig.cgi/dwarf-discuss-dwarfstd.org/2011-December/001173.html
DataExtractor debugFrameData(DObj->getDebugFrameSection(), isLittleEndian(),
DObj->getAddressSize());
DebugFrame.reset(new DWARFDebugFrame(false /* IsEH */));
DebugFrame->parse(debugFrameData);
return DebugFrame.get();
}
const DWARFDebugFrame *DWARFContext::getEHFrame() {
if (EHFrame)
return EHFrame.get();
DataExtractor debugFrameData(DObj->getEHFrameSection(), isLittleEndian(),
DObj->getAddressSize());
DebugFrame.reset(new DWARFDebugFrame(true /* IsEH */));
DebugFrame->parse(debugFrameData);
return DebugFrame.get();
}
const DWARFDebugMacro *DWARFContext::getDebugMacro() {
if (Macro)
return Macro.get();
DataExtractor MacinfoData(DObj->getMacinfoSection(), isLittleEndian(), 0);
Macro.reset(new DWARFDebugMacro());
Macro->parse(MacinfoData);
return Macro.get();
}
const DWARFLineTable *
DWARFContext::getLineTableForUnit(DWARFUnit *U) {
if (!Line)
Line.reset(new DWARFDebugLine);
auto UnitDIE = U->getUnitDIE();
if (!UnitDIE)
return nullptr;
auto Offset = toSectionOffset(UnitDIE.find(DW_AT_stmt_list));
if (!Offset)
return nullptr; // No line table for this compile unit.
uint32_t stmtOffset = *Offset + U->getLineTableOffset();
// See if the line table is cached.
if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
return lt;
// Make sure the offset is good before we try to parse.
if (stmtOffset >= U->getLineSection().Data.size())
return nullptr;
// We have to parse it first.
DWARFDataExtractor lineData(*DObj, U->getLineSection(), isLittleEndian(),
U->getAddressByteSize());
return Line->getOrParseLineTable(lineData, stmtOffset);
}
void DWARFContext::parseCompileUnits() {
CUs.parse(*this, DObj->getInfoSection());
}
void DWARFContext::parseTypeUnits() {
if (!TUs.empty())
return;
DObj->forEachTypesSections([&](const DWARFSection &S) {
TUs.emplace_back();
TUs.back().parse(*this, S);
});
}
void DWARFContext::parseDWOCompileUnits() {
DWOCUs.parseDWO(*this, DObj->getInfoDWOSection());
}
void DWARFContext::parseDWOTypeUnits() {
if (!DWOTUs.empty())
return;
DObj->forEachTypesDWOSections([&](const DWARFSection &S) {
DWOTUs.emplace_back();
DWOTUs.back().parseDWO(*this, S);
});
}
DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t Offset) {
parseCompileUnits();
return CUs.getUnitForOffset(Offset);
}
DWARFCompileUnit *DWARFContext::getCompileUnitForAddress(uint64_t Address) {
// First, get the offset of the compile unit.
uint32_t CUOffset = getDebugAranges()->findAddress(Address);
// Retrieve the compile unit.
return getCompileUnitForOffset(CUOffset);
}
static bool getFunctionNameAndStartLineForAddress(DWARFCompileUnit *CU,
uint64_t Address,
FunctionNameKind Kind,
std::string &FunctionName,
uint32_t &StartLine) {
// The address may correspond to instruction in some inlined function,
// so we have to build the chain of inlined functions and take the
// name of the topmost function in it.
SmallVector<DWARFDie, 4> InlinedChain;
CU->getInlinedChainForAddress(Address, InlinedChain);
if (InlinedChain.empty())
return false;
const DWARFDie &DIE = InlinedChain[0];
bool FoundResult = false;
const char *Name = nullptr;
if (Kind != FunctionNameKind::None && (Name = DIE.getSubroutineName(Kind))) {
FunctionName = Name;
FoundResult = true;
}
if (auto DeclLineResult = DIE.getDeclLine()) {
StartLine = DeclLineResult;
FoundResult = true;
}
return FoundResult;
}
DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
DILineInfoSpecifier Spec) {
DILineInfo Result;
DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
if (!CU)
return Result;
getFunctionNameAndStartLineForAddress(CU, Address, Spec.FNKind,
Result.FunctionName,
Result.StartLine);
if (Spec.FLIKind != FileLineInfoKind::None) {
if (const DWARFLineTable *LineTable = getLineTableForUnit(CU))
LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
Spec.FLIKind, Result);
}
return Result;
}
DILineInfoTable
DWARFContext::getLineInfoForAddressRange(uint64_t Address, uint64_t Size,
DILineInfoSpecifier Spec) {
DILineInfoTable Lines;
DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
if (!CU)
return Lines;
std::string FunctionName = "<invalid>";
uint32_t StartLine = 0;
getFunctionNameAndStartLineForAddress(CU, Address, Spec.FNKind, FunctionName,
StartLine);
// If the Specifier says we don't need FileLineInfo, just
// return the top-most function at the starting address.
if (Spec.FLIKind == FileLineInfoKind::None) {
DILineInfo Result;
Result.FunctionName = FunctionName;
Result.StartLine = StartLine;
Lines.push_back(std::make_pair(Address, Result));
return Lines;
}
const DWARFLineTable *LineTable = getLineTableForUnit(CU);
// Get the index of row we're looking for in the line table.
std::vector<uint32_t> RowVector;
if (!LineTable->lookupAddressRange(Address, Size, RowVector))
return Lines;
for (uint32_t RowIndex : RowVector) {
// Take file number and line/column from the row.
const DWARFDebugLine::Row &Row = LineTable->Rows[RowIndex];
DILineInfo Result;
LineTable->getFileNameByIndex(Row.File, CU->getCompilationDir(),
Spec.FLIKind, Result.FileName);
Result.FunctionName = FunctionName;
Result.Line = Row.Line;
Result.Column = Row.Column;
Result.StartLine = StartLine;
Lines.push_back(std::make_pair(Row.Address, Result));
}
return Lines;
}
DIInliningInfo
DWARFContext::getInliningInfoForAddress(uint64_t Address,
DILineInfoSpecifier Spec) {
DIInliningInfo InliningInfo;
DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
if (!CU)
return InliningInfo;
const DWARFLineTable *LineTable = nullptr;
SmallVector<DWARFDie, 4> InlinedChain;
CU->getInlinedChainForAddress(Address, InlinedChain);
if (InlinedChain.size() == 0) {
// If there is no DIE for address (e.g. it is in unavailable .dwo file),
// try to at least get file/line info from symbol table.
if (Spec.FLIKind != FileLineInfoKind::None) {
DILineInfo Frame;
LineTable = getLineTableForUnit(CU);
if (LineTable &&
LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
Spec.FLIKind, Frame))
InliningInfo.addFrame(Frame);
}
return InliningInfo;
}
uint32_t CallFile = 0, CallLine = 0, CallColumn = 0, CallDiscriminator = 0;
for (uint32_t i = 0, n = InlinedChain.size(); i != n; i++) {
DWARFDie &FunctionDIE = InlinedChain[i];
DILineInfo Frame;
// Get function name if necessary.
if (const char *Name = FunctionDIE.getSubroutineName(Spec.FNKind))
Frame.FunctionName = Name;
if (auto DeclLineResult = FunctionDIE.getDeclLine())
Frame.StartLine = DeclLineResult;
if (Spec.FLIKind != FileLineInfoKind::None) {
if (i == 0) {
// For the topmost frame, initialize the line table of this
// compile unit and fetch file/line info from it.
LineTable = getLineTableForUnit(CU);
// For the topmost routine, get file/line info from line table.
if (LineTable)
LineTable->getFileLineInfoForAddress(Address, CU->getCompilationDir(),
Spec.FLIKind, Frame);
} else {
// Otherwise, use call file, call line and call column from
// previous DIE in inlined chain.
if (LineTable)
LineTable->getFileNameByIndex(CallFile, CU->getCompilationDir(),
Spec.FLIKind, Frame.FileName);
Frame.Line = CallLine;
Frame.Column = CallColumn;
Frame.Discriminator = CallDiscriminator;
}
// Get call file/line/column of a current DIE.
if (i + 1 < n) {
FunctionDIE.getCallerFrame(CallFile, CallLine, CallColumn,
CallDiscriminator);
}
}
InliningInfo.addFrame(Frame);
}
return InliningInfo;
}
std::shared_ptr<DWARFContext>
DWARFContext::getDWOContext(StringRef AbsolutePath) {
if (auto S = DWP.lock()) {
DWARFContext *Ctxt = S->Context.get();
return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
}
std::weak_ptr<DWOFile> *Entry = &DWOFiles[AbsolutePath];
if (auto S = Entry->lock()) {
DWARFContext *Ctxt = S->Context.get();
return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
}
Expected<OwningBinary<ObjectFile>> Obj = [&] {
if (!CheckedForDWP) {
SmallString<128> DWPName;
auto Obj = object::ObjectFile::createObjectFile(
this->DWPName.empty()
? (DObj->getFileName() + ".dwp").toStringRef(DWPName)
: StringRef(this->DWPName));
if (Obj) {
Entry = &DWP;
return Obj;
} else {
CheckedForDWP = true;
// TODO: Should this error be handled (maybe in a high verbosity mode)
// before falling back to .dwo files?
consumeError(Obj.takeError());
}
}
return object::ObjectFile::createObjectFile(AbsolutePath);
}();
if (!Obj) {
// TODO: Actually report errors helpfully.
consumeError(Obj.takeError());
return nullptr;
}
auto S = std::make_shared<DWOFile>();
S->File = std::move(Obj.get());
S->Context = DWARFContext::create(*S->File.getBinary());
*Entry = S;
auto *Ctxt = S->Context.get();
return std::shared_ptr<DWARFContext>(std::move(S), Ctxt);
}
static Error createError(const Twine &Reason, llvm::Error E) {
return make_error<StringError>(Reason + toString(std::move(E)),
inconvertibleErrorCode());
}
/// SymInfo contains information about symbol: it's address
/// and section index which is -1LL for absolute symbols.
struct SymInfo {
uint64_t Address;
uint64_t SectionIndex;
};
/// Returns the address of symbol relocation used against and a section index.
/// Used for futher relocations computation. Symbol's section load address is
static Expected<SymInfo> getSymbolInfo(const object::ObjectFile &Obj,
const RelocationRef &Reloc,
const LoadedObjectInfo *L,
std::map<SymbolRef, SymInfo> &Cache) {
SymInfo Ret = {0, (uint64_t)-1LL};
object::section_iterator RSec = Obj.section_end();
object::symbol_iterator Sym = Reloc.getSymbol();
std::map<SymbolRef, SymInfo>::iterator CacheIt = Cache.end();
// First calculate the address of the symbol or section as it appears
// in the object file
if (Sym != Obj.symbol_end()) {
bool New;
std::tie(CacheIt, New) = Cache.insert({*Sym, {0, 0}});
if (!New)
return CacheIt->second;
Expected<uint64_t> SymAddrOrErr = Sym->getAddress();
if (!SymAddrOrErr)
return createError("failed to compute symbol address: ",
SymAddrOrErr.takeError());
// Also remember what section this symbol is in for later
auto SectOrErr = Sym->getSection();
if (!SectOrErr)
return createError("failed to get symbol section: ",
SectOrErr.takeError());
RSec = *SectOrErr;
Ret.Address = *SymAddrOrErr;
} else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) {
RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl());
Ret.Address = RSec->getAddress();
}
if (RSec != Obj.section_end())
Ret.SectionIndex = RSec->getIndex();
// If we are given load addresses for the sections, we need to adjust:
// SymAddr = (Address of Symbol Or Section in File) -
// (Address of Section in File) +
// (Load Address of Section)
// RSec is now either the section being targeted or the section
// containing the symbol being targeted. In either case,
// we need to perform the same computation.
if (L && RSec != Obj.section_end())
if (uint64_t SectionLoadAddress = L->getSectionLoadAddress(*RSec))
Ret.Address += SectionLoadAddress - RSec->getAddress();
if (CacheIt != Cache.end())
CacheIt->second = Ret;
return Ret;
}
static bool isRelocScattered(const object::ObjectFile &Obj,
const RelocationRef &Reloc) {
const MachOObjectFile *MachObj = dyn_cast<MachOObjectFile>(&Obj);
if (!MachObj)
return false;
// MachO also has relocations that point to sections and
// scattered relocations.
auto RelocInfo = MachObj->getRelocation(Reloc.getRawDataRefImpl());
return MachObj->isRelocationScattered(RelocInfo);
}
ErrorPolicy DWARFContext::defaultErrorHandler(Error E) {
errs() << "error: " + toString(std::move(E)) << '\n';
return ErrorPolicy::Continue;
}
namespace {
struct DWARFSectionMap final : public DWARFSection {
RelocAddrMap Relocs;
};
class DWARFObjInMemory final : public DWARFObject {
bool IsLittleEndian;
uint8_t AddressSize;
StringRef FileName;
const object::ObjectFile *Obj = nullptr;
std::vector<SectionName> SectionNames;
using TypeSectionMap = MapVector<object::SectionRef, DWARFSectionMap,
std::map<object::SectionRef, unsigned>>;
TypeSectionMap TypesSections;
TypeSectionMap TypesDWOSections;
DWARFSectionMap InfoSection;
DWARFSectionMap LocSection;
DWARFSectionMap LineSection;
DWARFSectionMap RangeSection;
DWARFSectionMap StringOffsetSection;
DWARFSectionMap InfoDWOSection;
DWARFSectionMap LineDWOSection;
DWARFSectionMap LocDWOSection;
DWARFSectionMap StringOffsetDWOSection;
DWARFSectionMap RangeDWOSection;
DWARFSectionMap AddrSection;
DWARFSectionMap AppleNamesSection;
DWARFSectionMap AppleTypesSection;
DWARFSectionMap AppleNamespacesSection;
DWARFSectionMap AppleObjCSection;
DWARFSectionMap *mapNameToDWARFSection(StringRef Name) {
return StringSwitch<DWARFSectionMap *>(Name)
.Case("debug_info", &InfoSection)
.Case("debug_loc", &LocSection)
.Case("debug_line", &LineSection)
.Case("debug_str_offsets", &StringOffsetSection)
.Case("debug_ranges", &RangeSection)
.Case("debug_info.dwo", &InfoDWOSection)
.Case("debug_loc.dwo", &LocDWOSection)
.Case("debug_line.dwo", &LineDWOSection)
.Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
.Case("debug_addr", &AddrSection)
.Case("apple_names", &AppleNamesSection)
.Case("apple_types", &AppleTypesSection)
.Case("apple_namespaces", &AppleNamespacesSection)
.Case("apple_namespac", &AppleNamespacesSection)
.Case("apple_objc", &AppleObjCSection)
.Default(nullptr);
}
StringRef AbbrevSection;
StringRef ARangeSection;
StringRef DebugFrameSection;
StringRef EHFrameSection;
StringRef StringSection;
StringRef MacinfoSection;
StringRef PubNamesSection;
StringRef PubTypesSection;
StringRef GnuPubNamesSection;
StringRef AbbrevDWOSection;
StringRef StringDWOSection;
StringRef GnuPubTypesSection;
StringRef CUIndexSection;
StringRef GdbIndexSection;
StringRef TUIndexSection;
SmallVector<SmallString<32>, 4> UncompressedSections;
StringRef *mapSectionToMember(StringRef Name) {
if (DWARFSection *Sec = mapNameToDWARFSection(Name))
return &Sec->Data;
return StringSwitch<StringRef *>(Name)
.Case("debug_abbrev", &AbbrevSection)
.Case("debug_aranges", &ARangeSection)
.Case("debug_frame", &DebugFrameSection)
.Case("eh_frame", &EHFrameSection)
.Case("debug_str", &StringSection)
.Case("debug_macinfo", &MacinfoSection)
.Case("debug_pubnames", &PubNamesSection)
.Case("debug_pubtypes", &PubTypesSection)
.Case("debug_gnu_pubnames", &GnuPubNamesSection)
.Case("debug_gnu_pubtypes", &GnuPubTypesSection)
.Case("debug_abbrev.dwo", &AbbrevDWOSection)
.Case("debug_str.dwo", &StringDWOSection)
.Case("debug_cu_index", &CUIndexSection)
.Case("debug_tu_index", &TUIndexSection)
.Case("gdb_index", &GdbIndexSection)
// Any more debug info sections go here.
.Default(nullptr);
}
/// If Sec is compressed section, decompresses and updates its contents
/// provided by Data. Otherwise leaves it unchanged.
Error maybeDecompress(const object::SectionRef &Sec, StringRef Name,
StringRef &Data) {
if (!Decompressor::isCompressed(Sec))
return Error::success();
Expected<Decompressor> Decompressor =
Decompressor::create(Name, Data, IsLittleEndian, AddressSize == 8);
if (!Decompressor)
return Decompressor.takeError();
SmallString<32> Out;
if (auto Err = Decompressor->resizeAndDecompress(Out))
return Err;
UncompressedSections.emplace_back(std::move(Out));
Data = UncompressedSections.back();
return Error::success();
}
public:
DWARFObjInMemory(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
uint8_t AddrSize, bool IsLittleEndian)
: IsLittleEndian(IsLittleEndian) {
for (const auto &SecIt : Sections) {
if (StringRef *SectionData = mapSectionToMember(SecIt.first()))
*SectionData = SecIt.second->getBuffer();
}
}
DWARFObjInMemory(const object::ObjectFile &Obj, const LoadedObjectInfo *L,
function_ref<ErrorPolicy(Error)> HandleError)
: IsLittleEndian(Obj.isLittleEndian()),
AddressSize(Obj.getBytesInAddress()), FileName(Obj.getFileName()),
Obj(&Obj) {
StringMap<unsigned> SectionAmountMap;
for (const SectionRef &Section : Obj.sections()) {
StringRef Name;
Section.getName(Name);
++SectionAmountMap[Name];
SectionNames.push_back({ Name, true });
// Skip BSS and Virtual sections, they aren't interesting.
if (Section.isBSS() || Section.isVirtual())
continue;
StringRef Data;
section_iterator RelocatedSection = Section.getRelocatedSection();
// Try to obtain an already relocated version of this section.
// Else use the unrelocated section from the object file. We'll have to
// apply relocations ourselves later.
if (!L || !L->getLoadedSectionContents(*RelocatedSection, Data))
Section.getContents(Data);
if (auto Err = maybeDecompress(Section, Name, Data)) {
ErrorPolicy EP = HandleError(createError(
"failed to decompress '" + Name + "', ", std::move(Err)));
if (EP == ErrorPolicy::Halt)
return;
continue;
}
// Compressed sections names in GNU style starts from ".z",
// at this point section is decompressed and we drop compression prefix.
Name = Name.substr(
Name.find_first_not_of("._z")); // Skip ".", "z" and "_" prefixes.
// Map platform specific debug section names to DWARF standard section
// names.
Name = Obj.mapDebugSectionName(Name);
if (StringRef *SectionData = mapSectionToMember(Name)) {
*SectionData = Data;
if (Name == "debug_ranges") {
// FIXME: Use the other dwo range section when we emit it.
RangeDWOSection.Data = Data;
}
} else if (Name == "debug_types") {
// Find debug_types data by section rather than name as there are
// multiple, comdat grouped, debug_types sections.
TypesSections[Section].Data = Data;
} else if (Name == "debug_types.dwo") {
TypesDWOSections[Section].Data = Data;
}
if (RelocatedSection == Obj.section_end())
continue;
StringRef RelSecName;
StringRef RelSecData;
RelocatedSection->getName(RelSecName);
// If the section we're relocating was relocated already by the JIT,
// then we used the relocated version above, so we do not need to process
// relocations for it now.
if (L && L->getLoadedSectionContents(*RelocatedSection, RelSecData))
continue;
// In Mach-o files, the relocations do not need to be applied if
// there is no load offset to apply. The value read at the
// relocation point already factors in the section address
// (actually applying the relocations will produce wrong results
// as the section address will be added twice).
if (!L && isa<MachOObjectFile>(&Obj))
continue;
RelSecName = RelSecName.substr(
RelSecName.find_first_not_of("._z")); // Skip . and _ prefixes.
// TODO: Add support for relocations in other sections as needed.
// Record relocations for the debug_info and debug_line sections.
DWARFSectionMap *Sec = mapNameToDWARFSection(RelSecName);
RelocAddrMap *Map = Sec ? &Sec->Relocs : nullptr;
if (!Map) {
// Find debug_types relocs by section rather than name as there are
// multiple, comdat grouped, debug_types sections.
if (RelSecName == "debug_types")
Map =
&static_cast<DWARFSectionMap &>(TypesSections[*RelocatedSection])
.Relocs;
else if (RelSecName == "debug_types.dwo")
Map = &static_cast<DWARFSectionMap &>(
TypesDWOSections[*RelocatedSection])
.Relocs;
else
continue;
}
if (Section.relocation_begin() == Section.relocation_end())
continue;
// Symbol to [address, section index] cache mapping.
std::map<SymbolRef, SymInfo> AddrCache;
for (const RelocationRef &Reloc : Section.relocations()) {
// FIXME: it's not clear how to correctly handle scattered
// relocations.
if (isRelocScattered(Obj, Reloc))
continue;
Expected<SymInfo> SymInfoOrErr =
getSymbolInfo(Obj, Reloc, L, AddrCache);
if (!SymInfoOrErr) {
if (HandleError(SymInfoOrErr.takeError()) == ErrorPolicy::Halt)
return;
continue;
}
object::RelocVisitor V(Obj);
uint64_t Val = V.visit(Reloc.getType(), Reloc, SymInfoOrErr->Address);
if (V.error()) {
SmallString<32> Type;
Reloc.getTypeName(Type);
ErrorPolicy EP = HandleError(
createError("failed to compute relocation: " + Type + ", ",
errorCodeToError(object_error::parse_failed)));
if (EP == ErrorPolicy::Halt)
return;
continue;
}
RelocAddrEntry Rel = {SymInfoOrErr->SectionIndex, Val};
Map->insert({Reloc.getOffset(), Rel});
}
}
for (SectionName &S : SectionNames)
if (SectionAmountMap[S.Name] > 1)
S.IsNameUnique = false;
}
Optional<RelocAddrEntry> find(const DWARFSection &S,
uint64_t Pos) const override {
auto &Sec = static_cast<const DWARFSectionMap &>(S);
RelocAddrMap::const_iterator AI = Sec.Relocs.find(Pos);
if (AI == Sec.Relocs.end())
return None;
return AI->second;
}
const object::ObjectFile *getFile() const override { return Obj; }
ArrayRef<SectionName> getSectionNames() const override {
return SectionNames;
}
bool isLittleEndian() const override { return IsLittleEndian; }
StringRef getAbbrevDWOSection() const override { return AbbrevDWOSection; }
const DWARFSection &getLineDWOSection() const override {
return LineDWOSection;
}
const DWARFSection &getLocDWOSection() const override {
return LocDWOSection;
}
StringRef getStringDWOSection() const override { return StringDWOSection; }
const DWARFSection &getStringOffsetDWOSection() const override {
return StringOffsetDWOSection;
}
const DWARFSection &getRangeDWOSection() const override {
return RangeDWOSection;
}
const DWARFSection &getAddrSection() const override { return AddrSection; }
StringRef getCUIndexSection() const override { return CUIndexSection; }
StringRef getGdbIndexSection() const override { return GdbIndexSection; }
StringRef getTUIndexSection() const override { return TUIndexSection; }
// DWARF v5
const DWARFSection &getStringOffsetSection() const override {
return StringOffsetSection;
}
// Sections for DWARF5 split dwarf proposal.
const DWARFSection &getInfoDWOSection() const override {
return InfoDWOSection;
}
void forEachTypesDWOSections(
function_ref<void(const DWARFSection &)> F) const override {
for (auto &P : TypesDWOSections)
F(P.second);
}
StringRef getAbbrevSection() const override { return AbbrevSection; }
const DWARFSection &getLocSection() const override { return LocSection; }
StringRef getARangeSection() const override { return ARangeSection; }
StringRef getDebugFrameSection() const override { return DebugFrameSection; }
StringRef getEHFrameSection() const override { return EHFrameSection; }
const DWARFSection &getLineSection() const override { return LineSection; }
StringRef getStringSection() const override { return StringSection; }
const DWARFSection &getRangeSection() const override { return RangeSection; }
StringRef getMacinfoSection() const override { return MacinfoSection; }
StringRef getPubNamesSection() const override { return PubNamesSection; }
StringRef getPubTypesSection() const override { return PubTypesSection; }
StringRef getGnuPubNamesSection() const override {
return GnuPubNamesSection;
}
StringRef getGnuPubTypesSection() const override {
return GnuPubTypesSection;
}
const DWARFSection &getAppleNamesSection() const override {
return AppleNamesSection;
}
const DWARFSection &getAppleTypesSection() const override {
return AppleTypesSection;
}
const DWARFSection &getAppleNamespacesSection() const override {
return AppleNamespacesSection;
}
const DWARFSection &getAppleObjCSection() const override {
return AppleObjCSection;
}
StringRef getFileName() const override { return FileName; }
uint8_t getAddressSize() const override { return AddressSize; }
const DWARFSection &getInfoSection() const override { return InfoSection; }
void forEachTypesSections(
function_ref<void(const DWARFSection &)> F) const override {
for (auto &P : TypesSections)
F(P.second);
}
};
} // namespace
std::unique_ptr<DWARFContext>
DWARFContext::create(const object::ObjectFile &Obj, const LoadedObjectInfo *L,
function_ref<ErrorPolicy(Error)> HandleError,
std::string DWPName) {
auto DObj = llvm::make_unique<DWARFObjInMemory>(Obj, L, HandleError);
return llvm::make_unique<DWARFContext>(std::move(DObj), std::move(DWPName));
}
std::unique_ptr<DWARFContext>
DWARFContext::create(const StringMap<std::unique_ptr<MemoryBuffer>> &Sections,
uint8_t AddrSize, bool isLittleEndian) {
auto DObj =
llvm::make_unique<DWARFObjInMemory>(Sections, AddrSize, isLittleEndian);
return llvm::make_unique<DWARFContext>(std::move(DObj), "");
}
Error DWARFContext::loadRegisterInfo(const object::ObjectFile &Obj) {
// Detect the architecture from the object file. We usually don't need OS
// info to lookup a target and create register info.
Triple TT;
TT.setArch(Triple::ArchType(Obj.getArch()));
TT.setVendor(Triple::UnknownVendor);
TT.setOS(Triple::UnknownOS);
std::string TargetLookupError;
const Target *TheTarget =
TargetRegistry::lookupTarget(TT.str(), TargetLookupError);
if (!TargetLookupError.empty())
return make_error<StringError>(TargetLookupError, inconvertibleErrorCode());
RegInfo.reset(TheTarget->createMCRegInfo(TT.str()));
return Error::success();
}