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

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//===-- 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/SmallString.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugArangeSet.h"
#include "llvm/DebugInfo/DWARF/DWARFUnitIndex.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ELF.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
using namespace dwarf;
using namespace object;
#define DEBUG_TYPE "dwarf"
typedef DWARFDebugLine::LineTable DWARFLineTable;
typedef DILineInfoSpecifier::FileLineInfoKind FileLineInfoKind;
typedef DILineInfoSpecifier::FunctionNameKind FunctionNameKind;
static void dumpPubSection(raw_ostream &OS, StringRef Name, StringRef Data,
bool LittleEndian, bool GnuStyle) {
OS << "\n." << Name << " contents:\n";
DataExtractor pubNames(Data, LittleEndian, 0);
uint32_t offset = 0;
while (pubNames.isValidOffset(offset)) {
OS << "length = " << format("0x%08x", pubNames.getU32(&offset));
OS << " version = " << format("0x%04x", pubNames.getU16(&offset));
OS << " unit_offset = " << format("0x%08x", pubNames.getU32(&offset));
OS << " unit_size = " << format("0x%08x", pubNames.getU32(&offset)) << '\n';
if (GnuStyle)
OS << "Offset Linkage Kind Name\n";
else
OS << "Offset Name\n";
while (offset < Data.size()) {
uint32_t dieRef = pubNames.getU32(&offset);
if (dieRef == 0)
break;
OS << format("0x%8.8x ", dieRef);
if (GnuStyle) {
PubIndexEntryDescriptor desc(pubNames.getU8(&offset));
OS << format("%-8s", dwarf::GDBIndexEntryLinkageString(desc.Linkage))
<< ' ' << format("%-8s", dwarf::GDBIndexEntryKindString(desc.Kind))
<< ' ';
}
OS << '\"' << pubNames.getCStr(&offset) << "\"\n";
}
}
}
static void dumpAccelSection(raw_ostream &OS, StringRef Name,
const DWARFSection& Section, StringRef StringSection,
bool LittleEndian) {
DataExtractor AccelSection(Section.Data, LittleEndian, 0);
DataExtractor StrData(StringSection, LittleEndian, 0);
OS << "\n." << Name << " contents:\n";
DWARFAcceleratorTable Accel(AccelSection, StrData, Section.Relocs);
if (!Accel.extract())
return;
Accel.dump(OS);
}
void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType, bool DumpEH) {
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);
}
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);
}
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);
}
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);
}
if (DumpType == DIDT_All || DumpType == DIDT_Loc) {
OS << "\n.debug_loc contents:\n";
getDebugLoc()->dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_LocDwo) {
OS << "\n.debug_loc.dwo contents:\n";
getDebugLocDWO()->dump(OS);
}
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(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();
const auto *CUDIE = CU->getUnitDIE();
if (CUDIE == nullptr)
continue;
unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
CU.get(), DW_AT_stmt_list, -1U);
if (stmtOffset != -1U) {
DataExtractor lineData(getLineSection().Data, isLittleEndian(),
savedAddressByteSize);
DWARFDebugLine::LineTable LineTable;
LineTable.parse(lineData, &getLineSection().Relocs, &stmtOffset);
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;
DataExtractor lineData(getLineDWOSection().Data, 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(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) &&
!getStringDWOSection().empty()) {
OS << "\n.debug_str.dwo contents:\n";
DataExtractor strDWOData(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).
DataExtractor rangesData(getRangeSection(), isLittleEndian(),
savedAddressByteSize);
offset = 0;
DWARFDebugRangeList rangeList;
while (rangeList.extract(rangesData, &offset))
rangeList.dump(OS);
}
if (DumpType == DIDT_All || DumpType == DIDT_Pubnames)
dumpPubSection(OS, "debug_pubnames", getPubNamesSection(),
isLittleEndian(), false);
if (DumpType == DIDT_All || DumpType == DIDT_Pubtypes)
dumpPubSection(OS, "debug_pubtypes", getPubTypesSection(),
isLittleEndian(), false);
if (DumpType == DIDT_All || DumpType == DIDT_GnuPubnames)
dumpPubSection(OS, "debug_gnu_pubnames", getGnuPubNamesSection(),
isLittleEndian(), true /* GnuStyle */);
if (DumpType == DIDT_All || DumpType == DIDT_GnuPubtypes)
dumpPubSection(OS, "debug_gnu_pubtypes", getGnuPubTypesSection(),
isLittleEndian(), true /* GnuStyle */);
if ((DumpType == DIDT_All || DumpType == DIDT_StrOffsetsDwo) &&
!getStringOffsetDWOSection().empty()) {
OS << "\n.debug_str_offsets.dwo contents:\n";
DataExtractor strOffsetExt(getStringOffsetDWOSection(), isLittleEndian(),
0);
offset = 0;
uint64_t size = getStringOffsetDWOSection().size();
while (offset < size) {
OS << format("0x%8.8x: ", offset);
OS << format("%8.8x\n", strOffsetExt.getU32(&offset));
}
}
if (DumpType == DIDT_All || DumpType == DIDT_AppleNames)
dumpAccelSection(OS, "apple_names", getAppleNamesSection(),
getStringSection(), isLittleEndian());
if (DumpType == DIDT_All || DumpType == DIDT_AppleTypes)
dumpAccelSection(OS, "apple_types", getAppleTypesSection(),
getStringSection(), isLittleEndian());
if (DumpType == DIDT_All || DumpType == DIDT_AppleNamespaces)
dumpAccelSection(OS, "apple_namespaces", getAppleNamespacesSection(),
getStringSection(), isLittleEndian());
if (DumpType == DIDT_All || DumpType == DIDT_AppleObjC)
dumpAccelSection(OS, "apple_objc", getAppleObjCSection(),
getStringSection(), isLittleEndian());
}
const DWARFUnitIndex &DWARFContext::getCUIndex() {
if (CUIndex)
return *CUIndex;
DataExtractor CUIndexData(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(getTUIndexSection(), isLittleEndian(), 0);
TUIndex = llvm::make_unique<DWARFUnitIndex>(DW_SECT_TYPES);
TUIndex->parse(TUIndexData);
return *TUIndex;
}
const DWARFDebugAbbrev *DWARFContext::getDebugAbbrev() {
if (Abbrev)
return Abbrev.get();
DataExtractor abbrData(getAbbrevSection(), isLittleEndian(), 0);
Abbrev.reset(new DWARFDebugAbbrev());
Abbrev->extract(abbrData);
return Abbrev.get();
}
const DWARFDebugAbbrev *DWARFContext::getDebugAbbrevDWO() {
if (AbbrevDWO)
return AbbrevDWO.get();
DataExtractor abbrData(getAbbrevDWOSection(), isLittleEndian(), 0);
AbbrevDWO.reset(new DWARFDebugAbbrev());
AbbrevDWO->extract(abbrData);
return AbbrevDWO.get();
}
const DWARFDebugLoc *DWARFContext::getDebugLoc() {
if (Loc)
return Loc.get();
DataExtractor LocData(getLocSection().Data, isLittleEndian(), 0);
Loc.reset(new DWARFDebugLoc(getLocSection().Relocs));
// assume all compile units have the same address byte size
if (getNumCompileUnits())
Loc->parse(LocData, getCompileUnitAtIndex(0)->getAddressByteSize());
return Loc.get();
}
const DWARFDebugLocDWO *DWARFContext::getDebugLocDWO() {
if (LocDWO)
return LocDWO.get();
DataExtractor LocData(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(getDebugFrameSection(), isLittleEndian(),
getAddressSize());
DebugFrame.reset(new DWARFDebugFrame(false /* IsEH */));
DebugFrame->parse(debugFrameData);
return DebugFrame.get();
}
const DWARFDebugFrame *DWARFContext::getEHFrame() {
if (EHFrame)
return EHFrame.get();
DataExtractor debugFrameData(getEHFrameSection(), isLittleEndian(),
getAddressSize());
DebugFrame.reset(new DWARFDebugFrame(true /* IsEH */));
DebugFrame->parse(debugFrameData);
return DebugFrame.get();
}
const DWARFDebugMacro *DWARFContext::getDebugMacro() {
if (Macro)
return Macro.get();
DataExtractor MacinfoData(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(&getLineSection().Relocs));
const auto *UnitDIE = U->getUnitDIE();
if (UnitDIE == nullptr)
return nullptr;
unsigned stmtOffset =
UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
if (stmtOffset == -1U)
return nullptr; // No line table for this compile unit.
stmtOffset += U->getLineTableOffset();
// See if the line table is cached.
if (const DWARFLineTable *lt = Line->getLineTable(stmtOffset))
return lt;
// We have to parse it first.
DataExtractor lineData(U->getLineSection(), isLittleEndian(),
U->getAddressByteSize());
return Line->getOrParseLineTable(lineData, stmtOffset);
}
void DWARFContext::parseCompileUnits() {
CUs.parse(*this, getInfoSection());
}
void DWARFContext::parseTypeUnits() {
if (!TUs.empty())
return;
for (const auto &I : getTypesSections()) {
TUs.emplace_back();
TUs.back().parse(*this, I.second);
}
}
void DWARFContext::parseDWOCompileUnits() {
DWOCUs.parseDWO(*this, getInfoDWOSection());
}
void DWARFContext::parseDWOTypeUnits() {
if (!DWOTUs.empty())
return;
for (const auto &I : getTypesDWOSections()) {
DWOTUs.emplace_back();
DWOTUs.back().parseDWO(*this, I.second);
}
}
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 getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
FunctionNameKind Kind,
std::string &FunctionName) {
if (Kind == FunctionNameKind::None)
return false;
// 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.
const DWARFDebugInfoEntryInlinedChain &InlinedChain =
CU->getInlinedChainForAddress(Address);
if (InlinedChain.DIEs.size() == 0)
return false;
const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
if (const char *Name =
TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
FunctionName = Name;
return true;
}
return false;
}
DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
DILineInfoSpecifier Spec) {
DILineInfo Result;
DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
if (!CU)
return Result;
getFunctionNameForAddress(CU, Address, Spec.FNKind, Result.FunctionName);
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>";
getFunctionNameForAddress(CU, Address, Spec.FNKind, FunctionName);
// 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;
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;
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;
const DWARFDebugInfoEntryInlinedChain &InlinedChain =
CU->getInlinedChainForAddress(Address);
if (InlinedChain.DIEs.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;
for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
DILineInfo Frame;
// Get function name if necessary.
if (const char *Name =
FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
Frame.FunctionName = Name;
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;
}
// Get call file/line/column of a current DIE.
if (i + 1 < n) {
FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
CallColumn);
}
}
InliningInfo.addFrame(Frame);
}
return InliningInfo;
}
static bool consumeCompressedGnuHeader(StringRef &data,
uint64_t &OriginalSize) {
// Consume "ZLIB" prefix.
if (!data.startswith("ZLIB"))
return false;
data = data.substr(4);
// Consume uncompressed section size (big-endian 8 bytes).
DataExtractor extractor(data, false, 8);
uint32_t Offset = 0;
OriginalSize = extractor.getU64(&Offset);
if (Offset == 0)
return false;
data = data.substr(Offset);
return true;
}
static bool consumeCompressedZLibHeader(StringRef &Data, uint64_t &OriginalSize,
bool IsLE, bool Is64Bit) {
using namespace ELF;
uint64_t HdrSize = Is64Bit ? sizeof(Elf64_Chdr) : sizeof(Elf32_Chdr);
if (Data.size() < HdrSize)
return false;
DataExtractor Extractor(Data, IsLE, 0);
uint32_t Offset = 0;
if (Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Word)
: sizeof(Elf32_Word)) !=
ELFCOMPRESS_ZLIB)
return false;
// Skip Elf64_Chdr::ch_reserved field.
if (Is64Bit)
Offset += sizeof(Elf64_Word);
OriginalSize = Extractor.getUnsigned(&Offset, Is64Bit ? sizeof(Elf64_Xword)
: sizeof(Elf32_Word));
Data = Data.substr(HdrSize);
return true;
}
static bool tryDecompress(StringRef &Name, StringRef &Data,
SmallString<32> &Out, bool ZLibStyle, bool IsLE,
bool Is64Bit) {
if (!zlib::isAvailable())
return false;
uint64_t OriginalSize;
bool Result =
ZLibStyle ? consumeCompressedZLibHeader(Data, OriginalSize, IsLE, Is64Bit)
: consumeCompressedGnuHeader(Data, OriginalSize);
if (!Result || zlib::uncompress(Data, Out, OriginalSize) != zlib::StatusOK)
return false;
// gnu-style names are started from "z", consume that.
if (!ZLibStyle)
Name = Name.substr(1);
return true;
}
DWARFContextInMemory::DWARFContextInMemory(const object::ObjectFile &Obj,
const LoadedObjectInfo *L)
: IsLittleEndian(Obj.isLittleEndian()),
AddressSize(Obj.getBytesInAddress()) {
for (const SectionRef &Section : Obj.sections()) {
StringRef name;
Section.getName(name);
// Skip BSS and Virtual sections, they aren't interesting.
bool IsBSS = Section.isBSS();
if (IsBSS)
continue;
bool IsVirtual = Section.isVirtual();
if (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);
name = name.substr(name.find_first_not_of("._")); // Skip . and _ prefixes.
bool ZLibStyleCompressed = Section.isCompressed();
if (ZLibStyleCompressed || name.startswith("zdebug_")) {
SmallString<32> Out;
if (!tryDecompress(name, data, Out, ZLibStyleCompressed, IsLittleEndian,
AddressSize == 8))
continue;
UncompressedSections.emplace_back(std::move(Out));
data = UncompressedSections.back();
}
StringRef *SectionData =
StringSwitch<StringRef *>(name)
.Case("debug_info", &InfoSection.Data)
.Case("debug_abbrev", &AbbrevSection)
.Case("debug_loc", &LocSection.Data)
.Case("debug_line", &LineSection.Data)
.Case("debug_aranges", &ARangeSection)
.Case("debug_frame", &DebugFrameSection)
.Case("eh_frame", &EHFrameSection)
.Case("debug_str", &StringSection)
.Case("debug_ranges", &RangeSection)
.Case("debug_macinfo", &MacinfoSection)
.Case("debug_pubnames", &PubNamesSection)
.Case("debug_pubtypes", &PubTypesSection)
.Case("debug_gnu_pubnames", &GnuPubNamesSection)
.Case("debug_gnu_pubtypes", &GnuPubTypesSection)
.Case("debug_info.dwo", &InfoDWOSection.Data)
.Case("debug_abbrev.dwo", &AbbrevDWOSection)
.Case("debug_loc.dwo", &LocDWOSection.Data)
.Case("debug_line.dwo", &LineDWOSection.Data)
.Case("debug_str.dwo", &StringDWOSection)
.Case("debug_str_offsets.dwo", &StringOffsetDWOSection)
.Case("debug_addr", &AddrSection)
.Case("apple_names", &AppleNamesSection.Data)
.Case("apple_types", &AppleTypesSection.Data)
.Case("apple_namespaces", &AppleNamespacesSection.Data)
.Case("apple_namespac", &AppleNamespacesSection.Data)
.Case("apple_objc", &AppleObjCSection.Data)
.Case("debug_cu_index", &CUIndexSection)
.Case("debug_tu_index", &TUIndexSection)
// Any more debug info sections go here.
.Default(nullptr);
if (SectionData) {
*SectionData = data;
if (name == "debug_ranges") {
// FIXME: Use the other dwo range section when we emit it.
RangeDWOSection = 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("._")); // Skip . and _ prefixes.
// TODO: Add support for relocations in other sections as needed.
// Record relocations for the debug_info and debug_line sections.
RelocAddrMap *Map = StringSwitch<RelocAddrMap*>(RelSecName)
.Case("debug_info", &InfoSection.Relocs)
.Case("debug_loc", &LocSection.Relocs)
.Case("debug_info.dwo", &InfoDWOSection.Relocs)
.Case("debug_line", &LineSection.Relocs)
.Case("apple_names", &AppleNamesSection.Relocs)
.Case("apple_types", &AppleTypesSection.Relocs)
.Case("apple_namespaces", &AppleNamespacesSection.Relocs)
.Case("apple_namespac", &AppleNamespacesSection.Relocs)
.Case("apple_objc", &AppleObjCSection.Relocs)
.Default(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 = &TypesSections[*RelocatedSection].Relocs;
else if (RelSecName == "debug_types.dwo")
Map = &TypesDWOSections[*RelocatedSection].Relocs;
else
continue;
}
if (Section.relocation_begin() != Section.relocation_end()) {
uint64_t SectionSize = RelocatedSection->getSize();
for (const RelocationRef &Reloc : Section.relocations()) {
uint64_t Address = Reloc.getOffset();
uint64_t Type = Reloc.getType();
uint64_t SymAddr = 0;
uint64_t SectionLoadAddress = 0;
object::symbol_iterator Sym = Reloc.getSymbol();
object::section_iterator RSec = Obj.section_end();
// First calculate the address of the symbol or section as it appears
// in the objct file
if (Sym != Obj.symbol_end()) {
ErrorOr<uint64_t> SymAddrOrErr = Sym->getAddress();
if (std::error_code EC = SymAddrOrErr.getError()) {
errs() << "error: failed to compute symbol address: "
<< EC.message() << '\n';
continue;
}
SymAddr = *SymAddrOrErr;
// Also remember what section this symbol is in for later
auto SectOrErr = Sym->getSection();
if (!SectOrErr) {
std::string Buf;
raw_string_ostream OS(Buf);
logAllUnhandledErrors(SectOrErr.takeError(), OS, "");
OS.flush();
errs() << "error: failed to get symbol section: "
<< Buf << '\n';
continue;
}
RSec = *SectOrErr;
} else if (auto *MObj = dyn_cast<MachOObjectFile>(&Obj)) {
// MachO also has relocations that point to sections and
// scattered relocations.
auto RelocInfo = MObj->getRelocation(Reloc.getRawDataRefImpl());
if (MObj->isRelocationScattered(RelocInfo)) {
// FIXME: it's not clear how to correctly handle scattered
// relocations.
continue;
} else {
RSec = MObj->getRelocationSection(Reloc.getRawDataRefImpl());
SymAddr = RSec->getAddress();
}
}
// 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)
if (L != nullptr && RSec != Obj.section_end()) {
// 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.
StringRef SecName;
RSec->getName(SecName);
// llvm::dbgs() << "Name: '" << SecName
// << "', RSec: " << RSec->getRawDataRefImpl()
// << ", Section: " << Section.getRawDataRefImpl() << "\n";
SectionLoadAddress = L->getSectionLoadAddress(*RSec);
if (SectionLoadAddress != 0)
SymAddr += SectionLoadAddress - RSec->getAddress();
}
object::RelocVisitor V(Obj);
object::RelocToApply R(V.visit(Type, Reloc, SymAddr));
if (V.error()) {
SmallString<32> Name;
Reloc.getTypeName(Name);
errs() << "error: failed to compute relocation: "
<< Name << "\n";
continue;
}
if (Address + R.Width > SectionSize) {
errs() << "error: " << R.Width << "-byte relocation starting "
<< Address << " bytes into section " << name << " which is "
<< SectionSize << " bytes long.\n";
continue;
}
if (R.Width > 8) {
errs() << "error: can't handle a relocation of more than 8 bytes at "
"a time.\n";
continue;
}
DEBUG(dbgs() << "Writing " << format("%p", R.Value)
<< " at " << format("%p", Address)
<< " with width " << format("%d", R.Width)
<< "\n");
Map->insert(std::make_pair(Address, std::make_pair(R.Width, R.Value)));
}
}
}
}
void DWARFContextInMemory::anchor() { }
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