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llvm-mirror/tools/llvm-objdump/MachODump.cpp
Rafael Espindola cca2985848 Add a function to get the segment name of a section. 
On MachO, sections also have segment names. When a tool looking at a .o file
prints a segment name, this is what they mean. In reality, a .o has only one
anonymous, segment.

This patch adds a MachO only function to fetch that segment name. I named it
getSectionFinalSegmentName since the main use for the name seems to be inform
the linker with segment this section should go to.

The patch also changes MachOObjectFile::getSectionName to return just the
section name instead of computing SegmentName,SectionName.

The main difference from the previous patch is that it doesn't use
InMemoryStruct. It is extremely dangerous: if the endians match it returns
a pointer to the file buffer, if not, it returns a pointer to an internal buffer
that is overwritten in the next API call.

We should change all of this code to use
support::detail::packed_endian_specific_integral like ELF, but since these
functions only handle strings, they work with big and little endian machines
as is.

I have tested this by installing ubuntu 12.10 ppc on qemu, that is why it took
so long :-)

llvm-svn: 170838
2012-12-21 03:47:03 +00:00

634 lines
23 KiB
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//===-- 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 "MCFunction.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/MC/MCAsmInfo.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/CommandLine.h"
#include "llvm/Support/Debug.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 "llvm/Support/system_error.h"
#include <algorithm>
#include <cstring>
using namespace llvm;
using namespace object;
static cl::opt<bool>
CFG("cfg", cl::desc("Create a CFG for every symbol in the object file and"
" write it to a graphviz file (MachO-only)"));
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 MachOObject *MachOObj) {
// Figure out the target triple.
if (TripleName.empty()) {
llvm::Triple TT("unknown-unknown-unknown");
switch (MachOObj->getHeader().CPUType) {
case llvm::MachO::CPUTypeI386:
TT.setArch(Triple::ArchType(Triple::x86));
break;
case llvm::MachO::CPUTypeX86_64:
TT.setArch(Triple::ArchType(Triple::x86_64));
break;
case llvm::MachO::CPUTypeARM:
TT.setArch(Triple::ArchType(Triple::arm));
break;
case llvm::MachO::CPUTypePowerPC:
TT.setArch(Triple::ArchType(Triple::ppc));
break;
case llvm::MachO::CPUTypePowerPC64:
TT.setArch(Triple::ArchType(Triple::ppc64));
break;
}
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 0;
}
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;
}
};
// Print additional information about an address, if available.
static void DumpAddress(uint64_t Address, ArrayRef<SectionRef> Sections,
MachOObject *MachOObj, raw_ostream &OS) {
for (unsigned i = 0; i != Sections.size(); ++i) {
uint64_t SectAddr = 0, SectSize = 0;
Sections[i].getAddress(SectAddr);
Sections[i].getSize(SectSize);
uint64_t addr = SectAddr;
if (SectAddr <= Address &&
SectAddr + SectSize > Address) {
StringRef bytes, name;
Sections[i].getContents(bytes);
Sections[i].getName(name);
// Print constant strings.
if (!name.compare("__cstring"))
OS << '"' << bytes.substr(addr, bytes.find('\0', addr)) << '"';
// Print constant CFStrings.
if (!name.compare("__cfstring"))
OS << "@\"" << bytes.substr(addr, bytes.find('\0', addr)) << '"';
}
}
}
typedef std::map<uint64_t, MCFunction*> FunctionMapTy;
typedef SmallVector<MCFunction, 16> FunctionListTy;
static void createMCFunctionAndSaveCalls(StringRef Name,
const MCDisassembler *DisAsm,
MemoryObject &Object, uint64_t Start,
uint64_t End,
MCInstrAnalysis *InstrAnalysis,
uint64_t Address,
raw_ostream &DebugOut,
FunctionMapTy &FunctionMap,
FunctionListTy &Functions) {
SmallVector<uint64_t, 16> Calls;
MCFunction f =
MCFunction::createFunctionFromMC(Name, DisAsm, Object, Start, End,
InstrAnalysis, DebugOut, Calls);
Functions.push_back(f);
FunctionMap[Address] = &Functions.back();
// Add the gathered callees to the map.
for (unsigned i = 0, e = Calls.size(); i != e; ++i)
FunctionMap.insert(std::make_pair(Calls[i], (MCFunction*)0));
}
// Write a graphviz file for the CFG inside an MCFunction.
static void emitDOTFile(const char *FileName, const MCFunction &f,
MCInstPrinter *IP) {
// Start a new dot file.
std::string Error;
raw_fd_ostream Out(FileName, Error);
if (!Error.empty()) {
errs() << "llvm-objdump: warning: " << Error << '\n';
return;
}
Out << "digraph " << f.getName() << " {\n";
Out << "graph [ rankdir = \"LR\" ];\n";
for (MCFunction::iterator i = f.begin(), e = f.end(); i != e; ++i) {
bool hasPreds = false;
// Only print blocks that have predecessors.
// FIXME: Slow.
for (MCFunction::iterator pi = f.begin(), pe = f.end(); pi != pe;
++pi)
if (pi->second.contains(i->first)) {
hasPreds = true;
break;
}
if (!hasPreds && i != f.begin())
continue;
Out << '"' << i->first << "\" [ label=\"<a>";
// Print instructions.
for (unsigned ii = 0, ie = i->second.getInsts().size(); ii != ie;
++ii) {
// Escape special chars and print the instruction in mnemonic form.
std::string Str;
raw_string_ostream OS(Str);
IP->printInst(&i->second.getInsts()[ii].Inst, OS, "");
Out << DOT::EscapeString(OS.str()) << '|';
}
Out << "<o>\" shape=\"record\" ];\n";
// Add edges.
for (MCBasicBlock::succ_iterator si = i->second.succ_begin(),
se = i->second.succ_end(); si != se; ++si)
Out << i->first << ":o -> " << *si <<":a\n";
}
Out << "}\n";
}
static void getSectionsAndSymbols(const macho::Header &Header,
MachOObjectFile *MachOObj,
InMemoryStruct<macho::SymtabLoadCommand> *SymtabLC,
std::vector<SectionRef> &Sections,
std::vector<SymbolRef> &Symbols,
SmallVectorImpl<uint64_t> &FoundFns) {
error_code ec;
for (symbol_iterator SI = MachOObj->begin_symbols(),
SE = MachOObj->end_symbols(); SI != SE; SI.increment(ec))
Symbols.push_back(*SI);
for (section_iterator SI = MachOObj->begin_sections(),
SE = MachOObj->end_sections(); SI != SE; SI.increment(ec)) {
SectionRef SR = *SI;
StringRef SectName;
SR.getName(SectName);
Sections.push_back(*SI);
}
for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
const MachOObject::LoadCommandInfo &LCI =
MachOObj->getObject()->getLoadCommandInfo(i);
if (LCI.Command.Type == macho::LCT_FunctionStarts) {
// We found a function starts segment, parse the addresses for later
// consumption.
InMemoryStruct<macho::LinkeditDataLoadCommand> LLC;
MachOObj->getObject()->ReadLinkeditDataLoadCommand(LCI, LLC);
MachOObj->getObject()->ReadULEB128s(LLC->DataOffset, FoundFns);
}
}
}
void llvm::DisassembleInputMachO(StringRef Filename) {
OwningPtr<MemoryBuffer> Buff;
if (error_code ec = MemoryBuffer::getFileOrSTDIN(Filename, Buff)) {
errs() << "llvm-objdump: " << Filename << ": " << ec.message() << "\n";
return;
}
OwningPtr<MachOObjectFile> MachOOF(static_cast<MachOObjectFile*>(
ObjectFile::createMachOObjectFile(Buff.take())));
MachOObject *MachOObj = MachOOF->getObject();
const Target *TheTarget = GetTarget(MachOObj);
if (!TheTarget) {
// GetTarget prints out stuff.
return;
}
OwningPtr<const MCInstrInfo> InstrInfo(TheTarget->createMCInstrInfo());
OwningPtr<MCInstrAnalysis>
InstrAnalysis(TheTarget->createMCInstrAnalysis(InstrInfo.get()));
// Set up disassembler.
OwningPtr<const MCAsmInfo> AsmInfo(TheTarget->createMCAsmInfo(TripleName));
OwningPtr<const MCSubtargetInfo>
STI(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
OwningPtr<const MCDisassembler> DisAsm(TheTarget->createMCDisassembler(*STI));
OwningPtr<const MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
OwningPtr<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";
const macho::Header &Header = MachOObj->getHeader();
const MachOObject::LoadCommandInfo *SymtabLCI = 0;
// First, find the symbol table segment.
for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
const MachOObject::LoadCommandInfo &LCI = MachOObj->getLoadCommandInfo(i);
if (LCI.Command.Type == macho::LCT_Symtab) {
SymtabLCI = &LCI;
break;
}
}
// Read and register the symbol table data.
InMemoryStruct<macho::SymtabLoadCommand> SymtabLC;
if (SymtabLCI) {
MachOObj->ReadSymtabLoadCommand(*SymtabLCI, SymtabLC);
MachOObj->RegisterStringTable(*SymtabLC);
}
std::vector<SectionRef> Sections;
std::vector<SymbolRef> Symbols;
SmallVector<uint64_t, 8> FoundFns;
getSectionsAndSymbols(Header, MachOOF.get(), &SymtabLC, Sections, Symbols,
FoundFns);
// Make a copy of the unsorted symbol list. FIXME: duplication
std::vector<SymbolRef> UnsortedSymbols(Symbols);
// Sort the symbols by address, just in case they didn't come in that way.
std::sort(Symbols.begin(), Symbols.end(), SymbolSorter());
#ifndef NDEBUG
raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
#else
raw_ostream &DebugOut = nulls();
#endif
OwningPtr<DIContext> diContext;
ObjectFile *DbgObj = MachOOF.get();
// 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()) {
OwningPtr<MemoryBuffer> Buf;
if (error_code ec = MemoryBuffer::getFileOrSTDIN(DSYMFile.c_str(), Buf)) {
errs() << "llvm-objdump: " << Filename << ": " << ec.message() << '\n';
return;
}
DbgObj = ObjectFile::createMachOObjectFile(Buf.take());
}
// Setup the DIContext
diContext.reset(DIContext::getDWARFContext(DbgObj));
}
FunctionMapTy FunctionMap;
FunctionListTy Functions;
for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
StringRef SectName;
if (Sections[SectIdx].getName(SectName) ||
SectName != "__text")
continue; // Skip non-text sections
StringRef SegmentName;
DataRefImpl DR = Sections[SectIdx].getRawDataRefImpl();
if (MachOOF->getSectionFinalSegmentName(DR, SegmentName) ||
SegmentName != "__TEXT")
continue;
// Insert the functions from the function starts segment into our map.
uint64_t VMAddr;
Sections[SectIdx].getAddress(VMAddr);
for (unsigned i = 0, e = FoundFns.size(); i != e; ++i) {
StringRef SectBegin;
Sections[SectIdx].getContents(SectBegin);
uint64_t Offset = (uint64_t)SectBegin.data();
FunctionMap.insert(std::make_pair(VMAddr + FoundFns[i]-Offset,
(MCFunction*)0));
}
StringRef Bytes;
Sections[SectIdx].getContents(Bytes);
StringRefMemoryObject memoryObject(Bytes);
bool symbolTableWorked = false;
// Parse relocations.
std::vector<std::pair<uint64_t, SymbolRef> > Relocs;
error_code ec;
for (relocation_iterator RI = Sections[SectIdx].begin_relocations(),
RE = Sections[SectIdx].end_relocations(); RI != RE; RI.increment(ec)) {
uint64_t RelocOffset, SectionAddress;
RI->getAddress(RelocOffset);
Sections[SectIdx].getAddress(SectionAddress);
RelocOffset -= SectionAddress;
SymbolRef RelocSym;
RI->getSymbol(RelocSym);
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;
if (!CFG) {
// Normal disassembly, print addresses, bytes and mnemonic form.
StringRef SymName;
Symbols[SymIdx].getName(SymName);
outs() << SymName << ":\n";
DILineInfo lastLine;
for (uint64_t Index = Start; Index < End; Index += Size) {
MCInst Inst;
if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
DebugOut, nulls())) {
uint64_t SectAddress = 0;
Sections[SectIdx].getAddress(SectAddress);
outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
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.getLine() != 0)
outs() << "\t## " << dli.getFileName() << ':'
<< dli.getLine() << ':' << dli.getColumn();
lastLine = dli;
}
outs() << "\n";
} else {
errs() << "llvm-objdump: warning: invalid instruction encoding\n";
if (Size == 0)
Size = 1; // skip illegible bytes
}
}
} else {
// Create CFG and use it for disassembly.
StringRef SymName;
Symbols[SymIdx].getName(SymName);
createMCFunctionAndSaveCalls(
SymName, DisAsm.get(), memoryObject, Start, End,
InstrAnalysis.get(), Start, DebugOut, FunctionMap, Functions);
}
}
if (!CFG && !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
}
}
}
if (CFG) {
if (!symbolTableWorked) {
// Reading the symbol table didn't work, create a big __TEXT symbol.
uint64_t SectSize = 0, SectAddress = 0;
Sections[SectIdx].getSize(SectSize);
Sections[SectIdx].getAddress(SectAddress);
createMCFunctionAndSaveCalls("__TEXT", DisAsm.get(), memoryObject,
0, SectSize,
InstrAnalysis.get(),
SectAddress, DebugOut,
FunctionMap, Functions);
}
for (std::map<uint64_t, MCFunction*>::iterator mi = FunctionMap.begin(),
me = FunctionMap.end(); mi != me; ++mi)
if (mi->second == 0) {
// Create functions for the remaining callees we have gathered,
// but we didn't find a name for them.
uint64_t SectSize = 0;
Sections[SectIdx].getSize(SectSize);
SmallVector<uint64_t, 16> Calls;
MCFunction f =
MCFunction::createFunctionFromMC("unknown", DisAsm.get(),
memoryObject, mi->first,
SectSize,
InstrAnalysis.get(), DebugOut,
Calls);
Functions.push_back(f);
mi->second = &Functions.back();
for (unsigned i = 0, e = Calls.size(); i != e; ++i) {
std::pair<uint64_t, MCFunction*> p(Calls[i], (MCFunction*)0);
if (FunctionMap.insert(p).second)
mi = FunctionMap.begin();
}
}
DenseSet<uint64_t> PrintedBlocks;
for (unsigned ffi = 0, ffe = Functions.size(); ffi != ffe; ++ffi) {
MCFunction &f = Functions[ffi];
for (MCFunction::iterator fi = f.begin(), fe = f.end(); fi != fe; ++fi){
if (!PrintedBlocks.insert(fi->first).second)
continue; // We already printed this block.
// We assume a block has predecessors when it's the first block after
// a symbol.
bool hasPreds = FunctionMap.find(fi->first) != FunctionMap.end();
// See if this block has predecessors.
// FIXME: Slow.
for (MCFunction::iterator pi = f.begin(), pe = f.end(); pi != pe;
++pi)
if (pi->second.contains(fi->first)) {
hasPreds = true;
break;
}
uint64_t SectSize = 0, SectAddress;
Sections[SectIdx].getSize(SectSize);
Sections[SectIdx].getAddress(SectAddress);
// No predecessors, this is a data block. Print as .byte directives.
if (!hasPreds) {
uint64_t End = llvm::next(fi) == fe ? SectSize :
llvm::next(fi)->first;
outs() << "# " << End-fi->first << " bytes of data:\n";
for (unsigned pos = fi->first; pos != End; ++pos) {
outs() << format("%8x:\t", SectAddress + pos);
DumpBytes(StringRef(Bytes.data() + pos, 1));
outs() << format("\t.byte 0x%02x\n", (uint8_t)Bytes[pos]);
}
continue;
}
if (fi->second.contains(fi->first)) // Print a header for simple loops
outs() << "# Loop begin:\n";
DILineInfo lastLine;
// Walk over the instructions and print them.
for (unsigned ii = 0, ie = fi->second.getInsts().size(); ii != ie;
++ii) {
const MCDecodedInst &Inst = fi->second.getInsts()[ii];
// If there's a symbol at this address, print its name.
if (FunctionMap.find(SectAddress + Inst.Address) !=
FunctionMap.end())
outs() << FunctionMap[SectAddress + Inst.Address]-> getName()
<< ":\n";
outs() << format("%8" PRIx64 ":\t", SectAddress + Inst.Address);
DumpBytes(StringRef(Bytes.data() + Inst.Address, Inst.Size));
if (fi->second.contains(fi->first)) // Indent simple loops.
outs() << '\t';
IP->printInst(&Inst.Inst, outs(), "");
// Look for relocations inside this instructions, if there is one
// print its target and additional information if available.
for (unsigned j = 0; j != Relocs.size(); ++j)
if (Relocs[j].first >= SectAddress + Inst.Address &&
Relocs[j].first < SectAddress + Inst.Address + Inst.Size) {
StringRef SymName;
uint64_t Addr;
Relocs[j].second.getAddress(Addr);
Relocs[j].second.getName(SymName);
outs() << "\t# " << SymName << ' ';
DumpAddress(Addr, Sections, MachOObj, outs());
}
// If this instructions contains an address, see if we can evaluate
// it and print additional information.
uint64_t targ = InstrAnalysis->evaluateBranch(Inst.Inst,
Inst.Address,
Inst.Size);
if (targ != -1ULL)
DumpAddress(targ, Sections, MachOObj, outs());
// Print debug info.
if (diContext) {
DILineInfo dli =
diContext->getLineInfoForAddress(SectAddress + Inst.Address);
// Print valid line info if it changed.
if (dli != lastLine && dli.getLine() != 0)
outs() << "\t## " << dli.getFileName() << ':'
<< dli.getLine() << ':' << dli.getColumn();
lastLine = dli;
}
outs() << '\n';
}
}
emitDOTFile((f.getName().str() + ".dot").c_str(), f, IP.get());
}
}
}
}
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