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llvm-mirror/lib/DebugInfo/DWARF/DWARFContext.cpp
Greg Clayton 9a690524e7 Add the ability to get attribute values as Optional<T> 
When getting attributes it is sometimes nicer to use Optional<T> some of the time instead of magic values. I tried to cut over to only using the Optional values but it made many of the call sites very messy, so it makes sense the leave in the calls that can return a default value. Otherwise code that looks like this:

uint64_t CallColumn = Die.getAttributeValueAsAddress(DW_AT_call_line, 0);

Has to be turned into:

uint64_t CallColumn = 0;
if (auto CallColumnValue = Die.getAttributeValueAsAddress(DW_AT_call_line))
    CallColumn = *CallColumnValue;

The first snippet of code looks much better. But in cases where you want an offset that may or may not be there, the following code looks better:

if (auto StmtOffset = Die.getAttributeValueAsSectionOffset(DW_AT_stmt_list)) {
  // Use StmtOffset
}

Differential Revision: https://reviews.llvm.org/D27772

llvm-svn: 289731
2016-12-14 22:38:08 +00:00

900 lines
32 KiB
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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/Object/MachO.h"
#include "llvm/Object/RelocVisitor.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).data())
<< ' '
<< format("%-8s", dwarf::GDBIndexEntryKindString(desc.Kind).data())
<< ' ';
}
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,
bool 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);
}
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, 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);
}
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();
auto CUDIE = CU->getUnitDIE();
if (!CUDIE)
continue;
if (auto StmtOffset =
CUDIE.getAttributeValueAsSectionOffset(DW_AT_stmt_list)) {
DataExtractor lineData(getLineSection().Data, isLittleEndian(),
savedAddressByteSize);
DWARFDebugLine::LineTable LineTable;
uint32_t Offset = *StmtOffset;
LineTable.parse(lineData, &getLineSection().Relocs, &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;
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_GdbIndex) &&
!getGdbIndexSection().empty()) {
OS << "\n.gnu_index contents:\n";
getGdbIndex().dump(OS);
}
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;
}
DWARFGdbIndex &DWARFContext::getGdbIndex() {
if (GdbIndex)
return *GdbIndex;
DataExtractor GdbIndexData(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(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));
auto UnitDIE = U->getUnitDIE();
if (!UnitDIE)
return nullptr;
auto Offset = UnitDIE.getAttributeValueAsSectionOffset(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;
// 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.SmallVectorImpl<DWARFDie> &InlinedChain
SmallVector<DWARFDie, 4> InlinedChain;
CU->getInlinedChainForAddress(Address, InlinedChain);
if (InlinedChain.size() == 0)
return false;
if (const char *Name = InlinedChain[0].getSubroutineName(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;
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;
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 (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(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)
.Case("gdb_index", &GdbIndexSection)
// 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()) {
Expected<uint64_t> SymAddrOrErr = Sym->getAddress();
if (!SymAddrOrErr) {
std::string Buf;
raw_string_ostream OS(Buf);
logAllUnhandledErrors(SymAddrOrErr.takeError(), OS, "");
OS.flush();
errs() << "error: failed to compute symbol address: "
<< Buf << '\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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