llvm-6502/tools/llvm-objdump/MachODump.cpp
2014-08-12 11:52:59 +00:00

933 lines
32 KiB
C++

//===-- MachODump.cpp - Object file dumping utility for llvm --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the MachO-specific dumper for llvm-objdump.
//
//===----------------------------------------------------------------------===//
#include "llvm-objdump.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCDisassembler.h"
#include "llvm/MC/MCInst.h"
#include "llvm/MC/MCInstPrinter.h"
#include "llvm/MC/MCInstrAnalysis.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Object/MachO.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/MachO.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cstring>
#include <system_error>
using namespace llvm;
using namespace object;
static cl::opt<bool>
UseDbg("g", cl::desc("Print line information from debug info if available"));
static cl::opt<std::string>
DSYMFile("dsym", cl::desc("Use .dSYM file for debug info"));
static const Target *GetTarget(const MachOObjectFile *MachOObj) {
// Figure out the target triple.
if (TripleName.empty()) {
llvm::Triple TT("unknown-unknown-unknown");
TT.setArch(Triple::ArchType(MachOObj->getArch()));
TripleName = TT.str();
}
// Get the target specific parser.
std::string Error;
const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error);
if (TheTarget)
return TheTarget;
errs() << "llvm-objdump: error: unable to get target for '" << TripleName
<< "', see --version and --triple.\n";
return nullptr;
}
struct SymbolSorter {
bool operator()(const SymbolRef &A, const SymbolRef &B) {
SymbolRef::Type AType, BType;
A.getType(AType);
B.getType(BType);
uint64_t AAddr, BAddr;
if (AType != SymbolRef::ST_Function)
AAddr = 0;
else
A.getAddress(AAddr);
if (BType != SymbolRef::ST_Function)
BAddr = 0;
else
B.getAddress(BAddr);
return AAddr < BAddr;
}
};
// Types for the storted data in code table that is built before disassembly
// and the predicate function to sort them.
typedef std::pair<uint64_t, DiceRef> DiceTableEntry;
typedef std::vector<DiceTableEntry> DiceTable;
typedef DiceTable::iterator dice_table_iterator;
static bool
compareDiceTableEntries(const DiceTableEntry i,
const DiceTableEntry j) {
return i.first == j.first;
}
static void DumpDataInCode(const char *bytes, uint64_t Size,
unsigned short Kind) {
uint64_t Value;
switch (Kind) {
case MachO::DICE_KIND_DATA:
switch (Size) {
case 4:
Value = bytes[3] << 24 |
bytes[2] << 16 |
bytes[1] << 8 |
bytes[0];
outs() << "\t.long " << Value;
break;
case 2:
Value = bytes[1] << 8 |
bytes[0];
outs() << "\t.short " << Value;
break;
case 1:
Value = bytes[0];
outs() << "\t.byte " << Value;
break;
}
outs() << "\t@ KIND_DATA\n";
break;
case MachO::DICE_KIND_JUMP_TABLE8:
Value = bytes[0];
outs() << "\t.byte " << Value << "\t@ KIND_JUMP_TABLE8";
break;
case MachO::DICE_KIND_JUMP_TABLE16:
Value = bytes[1] << 8 |
bytes[0];
outs() << "\t.short " << Value << "\t@ KIND_JUMP_TABLE16";
break;
case MachO::DICE_KIND_JUMP_TABLE32:
Value = bytes[3] << 24 |
bytes[2] << 16 |
bytes[1] << 8 |
bytes[0];
outs() << "\t.long " << Value << "\t@ KIND_JUMP_TABLE32";
break;
default:
outs() << "\t@ data in code kind = " << Kind << "\n";
break;
}
}
static void getSectionsAndSymbols(const MachO::mach_header Header,
MachOObjectFile *MachOObj,
std::vector<SectionRef> &Sections,
std::vector<SymbolRef> &Symbols,
SmallVectorImpl<uint64_t> &FoundFns,
uint64_t &BaseSegmentAddress) {
for (const SymbolRef &Symbol : MachOObj->symbols())
Symbols.push_back(Symbol);
for (const SectionRef &Section : MachOObj->sections()) {
StringRef SectName;
Section.getName(SectName);
Sections.push_back(Section);
}
MachOObjectFile::LoadCommandInfo Command =
MachOObj->getFirstLoadCommandInfo();
bool BaseSegmentAddressSet = false;
for (unsigned i = 0; ; ++i) {
if (Command.C.cmd == MachO::LC_FUNCTION_STARTS) {
// We found a function starts segment, parse the addresses for later
// consumption.
MachO::linkedit_data_command LLC =
MachOObj->getLinkeditDataLoadCommand(Command);
MachOObj->ReadULEB128s(LLC.dataoff, FoundFns);
}
else if (Command.C.cmd == MachO::LC_SEGMENT) {
MachO::segment_command SLC =
MachOObj->getSegmentLoadCommand(Command);
StringRef SegName = SLC.segname;
if(!BaseSegmentAddressSet && SegName != "__PAGEZERO") {
BaseSegmentAddressSet = true;
BaseSegmentAddress = SLC.vmaddr;
}
}
if (i == Header.ncmds - 1)
break;
else
Command = MachOObj->getNextLoadCommandInfo(Command);
}
}
static void DisassembleInputMachO2(StringRef Filename,
MachOObjectFile *MachOOF);
void llvm::DisassembleInputMachO(StringRef Filename) {
ErrorOr<std::unique_ptr<MemoryBuffer>> Buff =
MemoryBuffer::getFileOrSTDIN(Filename);
if (std::error_code EC = Buff.getError()) {
errs() << "llvm-objdump: " << Filename << ": " << EC.message() << "\n";
return;
}
std::unique_ptr<MachOObjectFile> MachOOF =
std::move(ObjectFile::createMachOObjectFile(Buff.get()).get());
DisassembleInputMachO2(Filename, MachOOF.get());
}
static void DisassembleInputMachO2(StringRef Filename,
MachOObjectFile *MachOOF) {
const Target *TheTarget = GetTarget(MachOOF);
if (!TheTarget) {
// GetTarget prints out stuff.
return;
}
std::unique_ptr<const MCInstrInfo> InstrInfo(TheTarget->createMCInstrInfo());
std::unique_ptr<MCInstrAnalysis> InstrAnalysis(
TheTarget->createMCInstrAnalysis(InstrInfo.get()));
// Package up features to be passed to target/subtarget
std::string FeaturesStr;
if (MAttrs.size()) {
SubtargetFeatures Features;
for (unsigned i = 0; i != MAttrs.size(); ++i)
Features.AddFeature(MAttrs[i]);
FeaturesStr = Features.getString();
}
// Set up disassembler.
std::unique_ptr<const MCRegisterInfo> MRI(
TheTarget->createMCRegInfo(TripleName));
std::unique_ptr<const MCAsmInfo> AsmInfo(
TheTarget->createMCAsmInfo(*MRI, TripleName));
std::unique_ptr<const MCSubtargetInfo> STI(
TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
MCContext Ctx(AsmInfo.get(), MRI.get(), nullptr);
std::unique_ptr<const MCDisassembler> DisAsm(
TheTarget->createMCDisassembler(*STI, Ctx));
int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
AsmPrinterVariant, *AsmInfo, *InstrInfo, *MRI, *STI));
if (!InstrAnalysis || !AsmInfo || !STI || !DisAsm || !IP) {
errs() << "error: couldn't initialize disassembler for target "
<< TripleName << '\n';
return;
}
outs() << '\n' << Filename << ":\n\n";
MachO::mach_header Header = MachOOF->getHeader();
// FIXME: FoundFns isn't used anymore. Using symbols/LC_FUNCTION_STARTS to
// determine function locations will eventually go in MCObjectDisassembler.
// FIXME: Using the -cfg command line option, this code used to be able to
// annotate relocations with the referenced symbol's name, and if this was
// inside a __[cf]string section, the data it points to. This is now replaced
// by the upcoming MCSymbolizer, which needs the appropriate setup done above.
std::vector<SectionRef> Sections;
std::vector<SymbolRef> Symbols;
SmallVector<uint64_t, 8> FoundFns;
uint64_t BaseSegmentAddress;
getSectionsAndSymbols(Header, MachOOF, Sections, Symbols, FoundFns,
BaseSegmentAddress);
// Sort the symbols by address, just in case they didn't come in that way.
std::sort(Symbols.begin(), Symbols.end(), SymbolSorter());
// Build a data in code table that is sorted on by the address of each entry.
uint64_t BaseAddress = 0;
if (Header.filetype == MachO::MH_OBJECT)
Sections[0].getAddress(BaseAddress);
else
BaseAddress = BaseSegmentAddress;
DiceTable Dices;
for (dice_iterator DI = MachOOF->begin_dices(), DE = MachOOF->end_dices();
DI != DE; ++DI) {
uint32_t Offset;
DI->getOffset(Offset);
Dices.push_back(std::make_pair(BaseAddress + Offset, *DI));
}
array_pod_sort(Dices.begin(), Dices.end());
#ifndef NDEBUG
raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
#else
raw_ostream &DebugOut = nulls();
#endif
std::unique_ptr<DIContext> diContext;
ObjectFile *DbgObj = MachOOF;
// Try to find debug info and set up the DIContext for it.
if (UseDbg) {
// A separate DSym file path was specified, parse it as a macho file,
// get the sections and supply it to the section name parsing machinery.
if (!DSYMFile.empty()) {
ErrorOr<std::unique_ptr<MemoryBuffer>> Buf =
MemoryBuffer::getFileOrSTDIN(DSYMFile);
if (std::error_code EC = Buf.getError()) {
errs() << "llvm-objdump: " << Filename << ": " << EC.message() << '\n';
return;
}
DbgObj = ObjectFile::createMachOObjectFile(Buf.get()).get().release();
}
// Setup the DIContext
diContext.reset(DIContext::getDWARFContext(*DbgObj));
}
for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
bool SectIsText = false;
Sections[SectIdx].isText(SectIsText);
if (SectIsText == false)
continue;
StringRef SectName;
if (Sections[SectIdx].getName(SectName) ||
SectName != "__text")
continue; // Skip non-text sections
DataRefImpl DR = Sections[SectIdx].getRawDataRefImpl();
StringRef SegmentName = MachOOF->getSectionFinalSegmentName(DR);
if (SegmentName != "__TEXT")
continue;
StringRef Bytes;
Sections[SectIdx].getContents(Bytes);
StringRefMemoryObject memoryObject(Bytes);
bool symbolTableWorked = false;
// Parse relocations.
std::vector<std::pair<uint64_t, SymbolRef>> Relocs;
for (const RelocationRef &Reloc : Sections[SectIdx].relocations()) {
uint64_t RelocOffset, SectionAddress;
Reloc.getOffset(RelocOffset);
Sections[SectIdx].getAddress(SectionAddress);
RelocOffset -= SectionAddress;
symbol_iterator RelocSym = Reloc.getSymbol();
Relocs.push_back(std::make_pair(RelocOffset, *RelocSym));
}
array_pod_sort(Relocs.begin(), Relocs.end());
// Disassemble symbol by symbol.
for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) {
StringRef SymName;
Symbols[SymIdx].getName(SymName);
SymbolRef::Type ST;
Symbols[SymIdx].getType(ST);
if (ST != SymbolRef::ST_Function)
continue;
// Make sure the symbol is defined in this section.
bool containsSym = false;
Sections[SectIdx].containsSymbol(Symbols[SymIdx], containsSym);
if (!containsSym)
continue;
// Start at the address of the symbol relative to the section's address.
uint64_t SectionAddress = 0;
uint64_t Start = 0;
Sections[SectIdx].getAddress(SectionAddress);
Symbols[SymIdx].getAddress(Start);
Start -= SectionAddress;
// Stop disassembling either at the beginning of the next symbol or at
// the end of the section.
bool containsNextSym = false;
uint64_t NextSym = 0;
uint64_t NextSymIdx = SymIdx+1;
while (Symbols.size() > NextSymIdx) {
SymbolRef::Type NextSymType;
Symbols[NextSymIdx].getType(NextSymType);
if (NextSymType == SymbolRef::ST_Function) {
Sections[SectIdx].containsSymbol(Symbols[NextSymIdx],
containsNextSym);
Symbols[NextSymIdx].getAddress(NextSym);
NextSym -= SectionAddress;
break;
}
++NextSymIdx;
}
uint64_t SectSize;
Sections[SectIdx].getSize(SectSize);
uint64_t End = containsNextSym ? NextSym : SectSize;
uint64_t Size;
symbolTableWorked = true;
outs() << SymName << ":\n";
DILineInfo lastLine;
for (uint64_t Index = Start; Index < End; Index += Size) {
MCInst Inst;
uint64_t SectAddress = 0;
Sections[SectIdx].getAddress(SectAddress);
outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
// Check the data in code table here to see if this is data not an
// instruction to be disassembled.
DiceTable Dice;
Dice.push_back(std::make_pair(SectAddress + Index, DiceRef()));
dice_table_iterator DTI = std::search(Dices.begin(), Dices.end(),
Dice.begin(), Dice.end(),
compareDiceTableEntries);
if (DTI != Dices.end()){
uint16_t Length;
DTI->second.getLength(Length);
DumpBytes(StringRef(Bytes.data() + Index, Length));
uint16_t Kind;
DTI->second.getKind(Kind);
DumpDataInCode(Bytes.data() + Index, Length, Kind);
continue;
}
if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
DebugOut, nulls())) {
DumpBytes(StringRef(Bytes.data() + Index, Size));
IP->printInst(&Inst, outs(), "");
// Print debug info.
if (diContext) {
DILineInfo dli =
diContext->getLineInfoForAddress(SectAddress + Index);
// Print valid line info if it changed.
if (dli != lastLine && dli.Line != 0)
outs() << "\t## " << dli.FileName << ':' << dli.Line << ':'
<< dli.Column;
lastLine = dli;
}
outs() << "\n";
} else {
errs() << "llvm-objdump: warning: invalid instruction encoding\n";
if (Size == 0)
Size = 1; // skip illegible bytes
}
}
}
if (!symbolTableWorked) {
// Reading the symbol table didn't work, disassemble the whole section.
uint64_t SectAddress;
Sections[SectIdx].getAddress(SectAddress);
uint64_t SectSize;
Sections[SectIdx].getSize(SectSize);
uint64_t InstSize;
for (uint64_t Index = 0; Index < SectSize; Index += InstSize) {
MCInst Inst;
if (DisAsm->getInstruction(Inst, InstSize, memoryObject, Index,
DebugOut, nulls())) {
outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
DumpBytes(StringRef(Bytes.data() + Index, InstSize));
IP->printInst(&Inst, outs(), "");
outs() << "\n";
} else {
errs() << "llvm-objdump: warning: invalid instruction encoding\n";
if (InstSize == 0)
InstSize = 1; // skip illegible bytes
}
}
}
}
}
//===----------------------------------------------------------------------===//
// __compact_unwind section dumping
//===----------------------------------------------------------------------===//
namespace {
template <typename T> static uint64_t readNext(const char *&Buf) {
using llvm::support::little;
using llvm::support::unaligned;
uint64_t Val = support::endian::read<T, little, unaligned>(Buf);
Buf += sizeof(T);
return Val;
}
struct CompactUnwindEntry {
uint32_t OffsetInSection;
uint64_t FunctionAddr;
uint32_t Length;
uint32_t CompactEncoding;
uint64_t PersonalityAddr;
uint64_t LSDAAddr;
RelocationRef FunctionReloc;
RelocationRef PersonalityReloc;
RelocationRef LSDAReloc;
CompactUnwindEntry(StringRef Contents, unsigned Offset, bool Is64)
: OffsetInSection(Offset) {
if (Is64)
read<uint64_t>(Contents.data() + Offset);
else
read<uint32_t>(Contents.data() + Offset);
}
private:
template<typename UIntPtr>
void read(const char *Buf) {
FunctionAddr = readNext<UIntPtr>(Buf);
Length = readNext<uint32_t>(Buf);
CompactEncoding = readNext<uint32_t>(Buf);
PersonalityAddr = readNext<UIntPtr>(Buf);
LSDAAddr = readNext<UIntPtr>(Buf);
}
};
}
/// Given a relocation from __compact_unwind, consisting of the RelocationRef
/// and data being relocated, determine the best base Name and Addend to use for
/// display purposes.
///
/// 1. An Extern relocation will directly reference a symbol (and the data is
/// then already an addend), so use that.
/// 2. Otherwise the data is an offset in the object file's layout; try to find
// a symbol before it in the same section, and use the offset from there.
/// 3. Finally, if all that fails, fall back to an offset from the start of the
/// referenced section.
static void findUnwindRelocNameAddend(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const RelocationRef &Reloc,
uint64_t Addr,
StringRef &Name, uint64_t &Addend) {
if (Reloc.getSymbol() != Obj->symbol_end()) {
Reloc.getSymbol()->getName(Name);
Addend = Addr;
return;
}
auto RE = Obj->getRelocation(Reloc.getRawDataRefImpl());
SectionRef RelocSection = Obj->getRelocationSection(RE);
uint64_t SectionAddr;
RelocSection.getAddress(SectionAddr);
auto Sym = Symbols.upper_bound(Addr);
if (Sym == Symbols.begin()) {
// The first symbol in the object is after this reference, the best we can
// do is section-relative notation.
RelocSection.getName(Name);
Addend = Addr - SectionAddr;
return;
}
// Go back one so that SymbolAddress <= Addr.
--Sym;
section_iterator SymSection = Obj->section_end();
Sym->second.getSection(SymSection);
if (RelocSection == *SymSection) {
// There's a valid symbol in the same section before this reference.
Sym->second.getName(Name);
Addend = Addr - Sym->first;
return;
}
// There is a symbol before this reference, but it's in a different
// section. Probably not helpful to mention it, so use the section name.
RelocSection.getName(Name);
Addend = Addr - SectionAddr;
}
static void printUnwindRelocDest(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const RelocationRef &Reloc,
uint64_t Addr) {
StringRef Name;
uint64_t Addend;
findUnwindRelocNameAddend(Obj, Symbols, Reloc, Addr, Name, Addend);
outs() << Name;
if (Addend)
outs() << " + " << format("0x%" PRIx64, Addend);
}
static void
printMachOCompactUnwindSection(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const SectionRef &CompactUnwind) {
assert(Obj->isLittleEndian() &&
"There should not be a big-endian .o with __compact_unwind");
bool Is64 = Obj->is64Bit();
uint32_t PointerSize = Is64 ? sizeof(uint64_t) : sizeof(uint32_t);
uint32_t EntrySize = 3 * PointerSize + 2 * sizeof(uint32_t);
StringRef Contents;
CompactUnwind.getContents(Contents);
SmallVector<CompactUnwindEntry, 4> CompactUnwinds;
// First populate the initial raw offsets, encodings and so on from the entry.
for (unsigned Offset = 0; Offset < Contents.size(); Offset += EntrySize) {
CompactUnwindEntry Entry(Contents.data(), Offset, Is64);
CompactUnwinds.push_back(Entry);
}
// Next we need to look at the relocations to find out what objects are
// actually being referred to.
for (const RelocationRef &Reloc : CompactUnwind.relocations()) {
uint64_t RelocAddress;
Reloc.getOffset(RelocAddress);
uint32_t EntryIdx = RelocAddress / EntrySize;
uint32_t OffsetInEntry = RelocAddress - EntryIdx * EntrySize;
CompactUnwindEntry &Entry = CompactUnwinds[EntryIdx];
if (OffsetInEntry == 0)
Entry.FunctionReloc = Reloc;
else if (OffsetInEntry == PointerSize + 2 * sizeof(uint32_t))
Entry.PersonalityReloc = Reloc;
else if (OffsetInEntry == 2 * PointerSize + 2 * sizeof(uint32_t))
Entry.LSDAReloc = Reloc;
else
llvm_unreachable("Unexpected relocation in __compact_unwind section");
}
// Finally, we're ready to print the data we've gathered.
outs() << "Contents of __compact_unwind section:\n";
for (auto &Entry : CompactUnwinds) {
outs() << " Entry at offset "
<< format("0x%" PRIx32, Entry.OffsetInSection) << ":\n";
// 1. Start of the region this entry applies to.
outs() << " start: "
<< format("0x%" PRIx64, Entry.FunctionAddr) << ' ';
printUnwindRelocDest(Obj, Symbols, Entry.FunctionReloc,
Entry.FunctionAddr);
outs() << '\n';
// 2. Length of the region this entry applies to.
outs() << " length: "
<< format("0x%" PRIx32, Entry.Length) << '\n';
// 3. The 32-bit compact encoding.
outs() << " compact encoding: "
<< format("0x%08" PRIx32, Entry.CompactEncoding) << '\n';
// 4. The personality function, if present.
if (Entry.PersonalityReloc.getObjectFile()) {
outs() << " personality function: "
<< format("0x%" PRIx64, Entry.PersonalityAddr) << ' ';
printUnwindRelocDest(Obj, Symbols, Entry.PersonalityReloc,
Entry.PersonalityAddr);
outs() << '\n';
}
// 5. This entry's language-specific data area.
if (Entry.LSDAReloc.getObjectFile()) {
outs() << " LSDA: "
<< format("0x%" PRIx64, Entry.LSDAAddr) << ' ';
printUnwindRelocDest(Obj, Symbols, Entry.LSDAReloc, Entry.LSDAAddr);
outs() << '\n';
}
}
}
//===----------------------------------------------------------------------===//
// __unwind_info section dumping
//===----------------------------------------------------------------------===//
static void printRegularSecondLevelUnwindPage(const char *PageStart) {
const char *Pos = PageStart;
uint32_t Kind = readNext<uint32_t>(Pos);
(void)Kind;
assert(Kind == 2 && "kind for a regular 2nd level index should be 2");
uint16_t EntriesStart = readNext<uint16_t>(Pos);
uint16_t NumEntries = readNext<uint16_t>(Pos);
Pos = PageStart + EntriesStart;
for (unsigned i = 0; i < NumEntries; ++i) {
uint32_t FunctionOffset = readNext<uint32_t>(Pos);
uint32_t Encoding = readNext<uint32_t>(Pos);
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, FunctionOffset) << ", "
<< "encoding="
<< format("0x%08" PRIx32, Encoding)
<< '\n';
}
}
static void printCompressedSecondLevelUnwindPage(
const char *PageStart, uint32_t FunctionBase,
const SmallVectorImpl<uint32_t> &CommonEncodings) {
const char *Pos = PageStart;
uint32_t Kind = readNext<uint32_t>(Pos);
(void)Kind;
assert(Kind == 3 && "kind for a compressed 2nd level index should be 3");
uint16_t EntriesStart = readNext<uint16_t>(Pos);
uint16_t NumEntries = readNext<uint16_t>(Pos);
uint16_t EncodingsStart = readNext<uint16_t>(Pos);
readNext<uint16_t>(Pos);
auto PageEncodings = (support::ulittle32_t *)(PageStart + EncodingsStart);
Pos = PageStart + EntriesStart;
for (unsigned i = 0; i < NumEntries; ++i) {
uint32_t Entry = readNext<uint32_t>(Pos);
uint32_t FunctionOffset = FunctionBase + (Entry & 0xffffff);
uint32_t EncodingIdx = Entry >> 24;
uint32_t Encoding;
if (EncodingIdx < CommonEncodings.size())
Encoding = CommonEncodings[EncodingIdx];
else
Encoding = PageEncodings[EncodingIdx - CommonEncodings.size()];
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, FunctionOffset) << ", "
<< "encoding[" << EncodingIdx << "]="
<< format("0x%08" PRIx32, Encoding)
<< '\n';
}
}
static void
printMachOUnwindInfoSection(const MachOObjectFile *Obj,
std::map<uint64_t, SymbolRef> &Symbols,
const SectionRef &UnwindInfo) {
assert(Obj->isLittleEndian() &&
"There should not be a big-endian .o with __unwind_info");
outs() << "Contents of __unwind_info section:\n";
StringRef Contents;
UnwindInfo.getContents(Contents);
const char *Pos = Contents.data();
//===----------------------------------
// Section header
//===----------------------------------
uint32_t Version = readNext<uint32_t>(Pos);
outs() << " Version: "
<< format("0x%" PRIx32, Version) << '\n';
assert(Version == 1 && "only understand version 1");
uint32_t CommonEncodingsStart = readNext<uint32_t>(Pos);
outs() << " Common encodings array section offset: "
<< format("0x%" PRIx32, CommonEncodingsStart) << '\n';
uint32_t NumCommonEncodings = readNext<uint32_t>(Pos);
outs() << " Number of common encodings in array: "
<< format("0x%" PRIx32, NumCommonEncodings) << '\n';
uint32_t PersonalitiesStart = readNext<uint32_t>(Pos);
outs() << " Personality function array section offset: "
<< format("0x%" PRIx32, PersonalitiesStart) << '\n';
uint32_t NumPersonalities = readNext<uint32_t>(Pos);
outs() << " Number of personality functions in array: "
<< format("0x%" PRIx32, NumPersonalities) << '\n';
uint32_t IndicesStart = readNext<uint32_t>(Pos);
outs() << " Index array section offset: "
<< format("0x%" PRIx32, IndicesStart) << '\n';
uint32_t NumIndices = readNext<uint32_t>(Pos);
outs() << " Number of indices in array: "
<< format("0x%" PRIx32, NumIndices) << '\n';
//===----------------------------------
// A shared list of common encodings
//===----------------------------------
// These occupy indices in the range [0, N] whenever an encoding is referenced
// from a compressed 2nd level index table. In practice the linker only
// creates ~128 of these, so that indices are available to embed encodings in
// the 2nd level index.
SmallVector<uint32_t, 64> CommonEncodings;
outs() << " Common encodings: (count = " << NumCommonEncodings << ")\n";
Pos = Contents.data() + CommonEncodingsStart;
for (unsigned i = 0; i < NumCommonEncodings; ++i) {
uint32_t Encoding = readNext<uint32_t>(Pos);
CommonEncodings.push_back(Encoding);
outs() << " encoding[" << i << "]: " << format("0x%08" PRIx32, Encoding)
<< '\n';
}
//===----------------------------------
// Personality functions used in this executable
//===----------------------------------
// There should be only a handful of these (one per source language,
// roughly). Particularly since they only get 2 bits in the compact encoding.
outs() << " Personality functions: (count = " << NumPersonalities << ")\n";
Pos = Contents.data() + PersonalitiesStart;
for (unsigned i = 0; i < NumPersonalities; ++i) {
uint32_t PersonalityFn = readNext<uint32_t>(Pos);
outs() << " personality[" << i + 1
<< "]: " << format("0x%08" PRIx32, PersonalityFn) << '\n';
}
//===----------------------------------
// The level 1 index entries
//===----------------------------------
// These specify an approximate place to start searching for the more detailed
// information, sorted by PC.
struct IndexEntry {
uint32_t FunctionOffset;
uint32_t SecondLevelPageStart;
uint32_t LSDAStart;
};
SmallVector<IndexEntry, 4> IndexEntries;
outs() << " Top level indices: (count = " << NumIndices << ")\n";
Pos = Contents.data() + IndicesStart;
for (unsigned i = 0; i < NumIndices; ++i) {
IndexEntry Entry;
Entry.FunctionOffset = readNext<uint32_t>(Pos);
Entry.SecondLevelPageStart = readNext<uint32_t>(Pos);
Entry.LSDAStart = readNext<uint32_t>(Pos);
IndexEntries.push_back(Entry);
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, Entry.FunctionOffset) << ", "
<< "2nd level page offset="
<< format("0x%08" PRIx32, Entry.SecondLevelPageStart) << ", "
<< "LSDA offset="
<< format("0x%08" PRIx32, Entry.LSDAStart) << '\n';
}
//===----------------------------------
// Next come the LSDA tables
//===----------------------------------
// The LSDA layout is rather implicit: it's a contiguous array of entries from
// the first top-level index's LSDAOffset to the last (sentinel).
outs() << " LSDA descriptors:\n";
Pos = Contents.data() + IndexEntries[0].LSDAStart;
int NumLSDAs = (IndexEntries.back().LSDAStart - IndexEntries[0].LSDAStart) /
(2 * sizeof(uint32_t));
for (int i = 0; i < NumLSDAs; ++i) {
uint32_t FunctionOffset = readNext<uint32_t>(Pos);
uint32_t LSDAOffset = readNext<uint32_t>(Pos);
outs() << " [" << i << "]: "
<< "function offset="
<< format("0x%08" PRIx32, FunctionOffset) << ", "
<< "LSDA offset="
<< format("0x%08" PRIx32, LSDAOffset) << '\n';
}
//===----------------------------------
// Finally, the 2nd level indices
//===----------------------------------
// Generally these are 4K in size, and have 2 possible forms:
// + Regular stores up to 511 entries with disparate encodings
// + Compressed stores up to 1021 entries if few enough compact encoding
// values are used.
outs() << " Second level indices:\n";
for (unsigned i = 0; i < IndexEntries.size() - 1; ++i) {
// The final sentinel top-level index has no associated 2nd level page
if (IndexEntries[i].SecondLevelPageStart == 0)
break;
outs() << " Second level index[" << i << "]: "
<< "offset in section="
<< format("0x%08" PRIx32, IndexEntries[i].SecondLevelPageStart)
<< ", "
<< "base function offset="
<< format("0x%08" PRIx32, IndexEntries[i].FunctionOffset) << '\n';
Pos = Contents.data() + IndexEntries[i].SecondLevelPageStart;
uint32_t Kind = *(support::ulittle32_t *)Pos;
if (Kind == 2)
printRegularSecondLevelUnwindPage(Pos);
else if (Kind == 3)
printCompressedSecondLevelUnwindPage(Pos, IndexEntries[i].FunctionOffset,
CommonEncodings);
else
llvm_unreachable("Do not know how to print this kind of 2nd level page");
}
}
void llvm::printMachOUnwindInfo(const MachOObjectFile *Obj) {
std::map<uint64_t, SymbolRef> Symbols;
for (const SymbolRef &SymRef : Obj->symbols()) {
// Discard any undefined or absolute symbols. They're not going to take part
// in the convenience lookup for unwind info and just take up resources.
section_iterator Section = Obj->section_end();
SymRef.getSection(Section);
if (Section == Obj->section_end())
continue;
uint64_t Addr;
SymRef.getAddress(Addr);
Symbols.insert(std::make_pair(Addr, SymRef));
}
for (const SectionRef &Section : Obj->sections()) {
StringRef SectName;
Section.getName(SectName);
if (SectName == "__compact_unwind")
printMachOCompactUnwindSection(Obj, Symbols, Section);
else if (SectName == "__unwind_info")
printMachOUnwindInfoSection(Obj, Symbols, Section);
else if (SectName == "__eh_frame")
outs() << "llvm-objdump: warning: unhandled __eh_frame section\n";
}
}