Add a MachO-specific "mode" to llvm-objdump, that, if enabled, gathers additional information that are only available on MachO.

- It can take FunctionStarts from a binary to find entry points more accurately.
- Symbol offsets in executables are correct now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140028 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 489 insertions, 0 deletions

diff --git a/tools/llvm-objdump/MachODump.cpp b/tools/llvm-objdump/MachODump.cpp
new file mode 100644
index 0000000000..49687d1cea
--- /dev/null
+++ b/tools/llvm-objdump/MachODump.cpp
@@ -0,0 +1,489 @@
+//===-- 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/Support/MachO.h"
+#include "llvm/Object/MachOObject.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/ADT/STLExtras.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/MCSubtargetInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/GraphWriter.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 const Target *GetTarget(const MachOObject *MachOObj) {
+  // Figure out the target triple.
+  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 Section {
+  char Name[16];
+  uint64_t Address;
+  uint64_t Size;
+  uint32_t Offset;
+  uint32_t NumRelocs;
+  uint64_t RelocTableOffset;
+};
+
+struct Symbol {
+  uint64_t Value;
+  uint32_t StringIndex;
+  uint8_t SectionIndex;
+  bool operator<(const Symbol &RHS) const { return Value < RHS.Value; }
+};
+
+static void DumpAddress(uint64_t Address, ArrayRef<Section> Sections,
+                        MachOObject *MachOObj, raw_ostream &OS) {
+  for (unsigned i = 0; i != Sections.size(); ++i) {
+    uint64_t addr = Address-Sections[i].Address;
+    if (Sections[i].Address <= Address &&
+        Sections[i].Address + Sections[i].Size > Address) {
+      StringRef bytes = MachOObj->getData(Sections[i].Offset,
+                                          Sections[i].Size);
+      if (!strcmp(Sections[i].Name, "__cstring"))
+        OS << '"' << bytes.substr(addr, bytes.find('\0', addr)) << '"';
+      if (!strcmp(Sections[i].Name, "__cfstring"))
+        OS << "@\"" << bytes.substr(addr, bytes.find('\0', addr)) << '"';
+    }
+  }
+}
+
+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<MachOObject> MachOObj(MachOObject::LoadFromBuffer(Buff.take()));
+
+  const Target *TheTarget = GetTarget(MachOObj.get());
+  if (!TheTarget) {
+    // GetTarget prints out stuff.
+    return;
+  }
+  const MCInstrInfo *InstrInfo = TheTarget->createMCInstrInfo();
+  OwningPtr<MCInstrAnalysis>
+    InstrAnalysis(TheTarget->createMCInstrAnalysis(InstrInfo));
+
+  // Set up disassembler.
+  OwningPtr<const MCAsmInfo> AsmInfo(TheTarget->createMCAsmInfo(TripleName));
+
+  if (!AsmInfo) {
+    errs() << "error: no assembly info for target " << TripleName << "\n";
+    return;
+  }
+
+  OwningPtr<const MCSubtargetInfo>
+    STI(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
+
+  if (!STI) {
+    errs() << "error: no subtarget info for target " << TripleName << "\n";
+    return;
+  }
+
+  OwningPtr<const MCDisassembler> DisAsm(TheTarget->createMCDisassembler(*STI));
+  if (!DisAsm) {
+    errs() << "error: no disassembler for target " << TripleName << "\n";
+    return;
+  }
+
+  int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
+  OwningPtr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
+        AsmPrinterVariant, *AsmInfo, *STI));
+  if (!IP) {
+    errs() << "error: no instruction printer for target " << TripleName << '\n';
+    return;
+  }
+
+  outs() << '\n';
+  outs() << Filename << ":\n\n";
+
+  const macho::Header &Header = MachOObj->getHeader();
+
+  const MachOObject::LoadCommandInfo *SymtabLCI = 0;
+  for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
+    const MachOObject::LoadCommandInfo &LCI = MachOObj->getLoadCommandInfo(i);
+    switch (LCI.Command.Type) {
+    case macho::LCT_Symtab:
+      SymtabLCI = &LCI;
+      break;
+    }
+  }
+
+  // Read and register the symbol table data.
+  InMemoryStruct<macho::SymtabLoadCommand> SymtabLC;
+  MachOObj->ReadSymtabLoadCommand(*SymtabLCI, SymtabLC);
+  MachOObj->RegisterStringTable(*SymtabLC);
+
+  std::vector<Section> Sections;
+  std::vector<Symbol> Symbols;
+  std::vector<Symbol> UnsortedSymbols; // FIXME: duplication
+  SmallVector<uint64_t, 8> FoundFns;
+
+  for (unsigned i = 0; i != Header.NumLoadCommands; ++i) {
+    const MachOObject::LoadCommandInfo &LCI = MachOObj->getLoadCommandInfo(i);
+    if (LCI.Command.Type == macho::LCT_Segment) {
+      InMemoryStruct<macho::SegmentLoadCommand> SegmentLC;
+      MachOObj->ReadSegmentLoadCommand(LCI, SegmentLC);
+
+      for (unsigned SectNum = 0; SectNum != SegmentLC->NumSections; ++SectNum) {
+        InMemoryStruct<macho::Section> Sect;
+        MachOObj->ReadSection(LCI, SectNum, Sect);
+
+        Section S;
+        memcpy(S.Name, Sect->Name, 16);
+        S.Address = Sect->Address;
+        S.Size = Sect->Size;
+        S.Offset = Sect->Offset;
+        S.NumRelocs = Sect->NumRelocationTableEntries;
+        S.RelocTableOffset = Sect->RelocationTableOffset;
+        Sections.push_back(S);
+
+        for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) {
+          InMemoryStruct<macho::SymbolTableEntry> STE;
+          MachOObj->ReadSymbolTableEntry(SymtabLC->SymbolTableOffset, i, STE);
+
+          Symbol S;
+          S.StringIndex = STE->StringIndex;
+          S.SectionIndex = STE->SectionIndex;
+          S.Value = STE->Value;
+          Symbols.push_back(S);
+          UnsortedSymbols.push_back(Symbols.back());
+        }
+      }
+    } else if (LCI.Command.Type == macho::LCT_Segment64) {
+      InMemoryStruct<macho::Segment64LoadCommand> Segment64LC;
+      MachOObj->ReadSegment64LoadCommand(LCI, Segment64LC);
+
+      for (unsigned SectNum = 0; SectNum != Segment64LC->NumSections; ++SectNum) {
+        InMemoryStruct<macho::Section64> Sect64;
+        MachOObj->ReadSection64(LCI, SectNum, Sect64);
+
+        Section S;
+        memcpy(S.Name, Sect64->Name, 16);
+        S.Address = Sect64->Address;
+        S.Size = Sect64->Size;
+        S.Offset = Sect64->Offset;
+        S.NumRelocs = Sect64->NumRelocationTableEntries;
+        S.RelocTableOffset = Sect64->RelocationTableOffset;
+        Sections.push_back(S);
+
+        for (unsigned i = 0; i != SymtabLC->NumSymbolTableEntries; ++i) {
+          InMemoryStruct<macho::Symbol64TableEntry> STE;
+          MachOObj->ReadSymbol64TableEntry(SymtabLC->SymbolTableOffset, i, STE);
+
+          Symbol S;
+          S.StringIndex = STE->StringIndex;
+          S.SectionIndex = STE->SectionIndex;
+          S.Value = STE->Value;
+          Symbols.push_back(S);
+          UnsortedSymbols.push_back(Symbols.back());
+        }
+      }
+    } else if (LCI.Command.Type == macho::LCT_FunctionStarts) {
+      InMemoryStruct<macho::LinkeditDataLoadCommand> LLC;
+      MachOObj->ReadLinkeditDataLoadCommand(LCI, LLC);
+
+      MachOObj->ReadULEB128s(LLC->DataOffset, FoundFns);
+    }
+  }
+
+  std::map<uint64_t, MCFunction*> FunctionMap;
+
+  // Sort the symbols by address, just in case they didn't come in that way.
+  array_pod_sort(Symbols.begin(), Symbols.end());
+
+#ifndef NDEBUG
+  raw_ostream &DebugOut = DebugFlag ? dbgs() : nulls();
+#else
+  raw_ostream &DebugOut = nulls();
+#endif
+
+  SmallVector<MCFunction, 16> Functions;
+
+  for (unsigned SectIdx = 0; SectIdx != Sections.size(); SectIdx++) {
+    if (strcmp(Sections[SectIdx].Name, "__text"))
+      continue;
+
+    uint64_t VMAddr = Sections[SectIdx].Address - Sections[SectIdx].Offset;
+    for (unsigned i = 0, e = FoundFns.size(); i != e; ++i)
+      FunctionMap.insert(std::pair<uint64_t,MCFunction*>(FoundFns[i]+VMAddr,0));
+
+    StringRef Bytes = MachOObj->getData(Sections[SectIdx].Offset,
+                                        Sections[SectIdx].Size);
+    StringRefMemoryObject memoryObject(Bytes);
+    bool symbolTableWorked = false;
+
+    std::vector<std::pair<uint64_t, uint32_t> > Relocs;
+    for (unsigned j = 0; j != Sections[SectIdx].NumRelocs; ++j) {
+      InMemoryStruct<macho::RelocationEntry> RE;
+      MachOObj->ReadRelocationEntry(Sections[SectIdx].RelocTableOffset, j, RE);
+      Relocs.push_back(std::make_pair(RE->Word0, RE->Word1 & 0xffffff));
+    }
+    array_pod_sort(Relocs.begin(), Relocs.end());
+
+    for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) {
+      if ((unsigned)Symbols[SymIdx].SectionIndex - 1 != SectIdx)
+        continue;
+
+      uint64_t Start = Symbols[SymIdx].Value - Sections[SectIdx].Address;
+      uint64_t End = (SymIdx+1 == Symbols.size() ||
+          Symbols[SymIdx].SectionIndex != Symbols[SymIdx+1].SectionIndex) ?
+          Sections[SectIdx].Size :
+          Symbols[SymIdx+1].Value - Sections[SectIdx].Address;
+      uint64_t Size;
+
+      if (Start >= End)
+        continue;
+
+      symbolTableWorked = true;
+
+      if (!CFG) {
+        outs() << MachOObj->getStringAtIndex(Symbols[SymIdx].StringIndex)
+          << ":\n";
+        for (uint64_t Index = Start; Index < End; Index += Size) {
+          MCInst Inst;
+
+          if (DisAsm->getInstruction(Inst, Size, memoryObject, Index,
+                                     DebugOut, nulls())) {
+            outs() << format("%8llx:\t", Sections[SectIdx].Address + Index);
+            DumpBytes(StringRef(Bytes.data() + Index, Size));
+            IP->printInst(&Inst, outs(), "");
+            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.
+        SmallVector<uint64_t, 16> Calls;
+        MCFunction f =
+          MCFunction::createFunctionFromMC(
+              MachOObj->getStringAtIndex(Symbols[SymIdx].StringIndex),
+              DisAsm.get(),
+              memoryObject, Start, End,
+              InstrAnalysis.get(), DebugOut,
+              Calls);
+
+        Functions.push_back(f);
+        FunctionMap[Start] = &Functions.back();
+
+        for (unsigned i = 0, e = Calls.size(); i != e; ++i)
+          FunctionMap.insert(std::pair<uint64_t, MCFunction*>(Calls[i], 0));
+      }
+    }
+
+    if (CFG) {
+      if (!symbolTableWorked) {
+        // Create CFG and use it for disassembly.
+        SmallVector<uint64_t, 16> Calls;
+        MCFunction f =
+          MCFunction::createFunctionFromMC("__TEXT", DisAsm.get(),
+              memoryObject, 0, Sections[SectIdx].Size,
+              InstrAnalysis.get(), DebugOut,
+              Calls);
+
+        Functions.push_back(f);
+        FunctionMap[Sections[SectIdx].Offset] = &Functions.back();
+
+        for (unsigned i = 0, e = Calls.size(); i != e; ++i)
+          FunctionMap.insert(std::pair<uint64_t, MCFunction*>(Calls[i], 0));
+      }
+      for (std::map<uint64_t, MCFunction*>::iterator mi = FunctionMap.begin(),
+           me = FunctionMap.end(); mi != me; ++mi)
+        if (mi->second == 0) {
+          SmallVector<uint64_t, 16> Calls;
+          MCFunction f =
+            MCFunction::createFunctionFromMC("unknown", DisAsm.get(),
+                                             memoryObject, mi->first,
+                                             Sections[SectIdx].Size,
+                                             InstrAnalysis.get(), DebugOut,
+                                             Calls);
+          Functions.push_back(f);
+          mi->second = &Functions.back();
+          for (unsigned i = 0, e = Calls.size(); i != e; ++i)
+            if (FunctionMap.insert(std::pair<uint64_t, MCFunction*>(Calls[i],0))
+                                                                        .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;
+          bool hasPreds = FunctionMap.find(fi->first) != FunctionMap.end();
+
+          // Only print blocks that have predecessors.
+          // FIXME: Slow.
+          for (MCFunction::iterator pi = f.begin(), pe = f.end(); pi != pe;
+              ++pi)
+            if (pi->second.contains(fi->first)) {
+              hasPreds = true;
+              break;
+            }
+
+          // Data block.
+          if (!hasPreds && fi != f.begin()) {
+            uint64_t End = llvm::next(fi) == fe ? Sections[SectIdx].Size :
+                                                  llvm::next(fi)->first;
+            outs() << "# " << End-fi->first << " bytes of data:\n";
+            for (unsigned pos = fi->first; pos != End; ++pos) {
+              outs() << format("%8x:\t", Sections[SectIdx].Address + 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))
+            outs() << "# Loop begin:\n";
+
+          for (unsigned ii = 0, ie = fi->second.getInsts().size(); ii != ie;
+               ++ii) {
+            const MCDecodedInst &Inst = fi->second.getInsts()[ii];
+            if (FunctionMap.find(Sections[SectIdx].Address + Inst.Address) !=
+                FunctionMap.end())
+              outs() << FunctionMap[Sections[SectIdx].Address + Inst.Address]->
+                                                             getName() << ":\n";
+            outs() << format("%8llx:\t", Sections[SectIdx].Address +
+                                         Inst.Address);
+            DumpBytes(StringRef(Bytes.data() + Inst.Address, Inst.Size));
+            // Simple loops.
+            if (fi->second.contains(fi->first))
+              outs() << '\t';
+            IP->printInst(&Inst.Inst, outs(), "");
+            for (unsigned j = 0; j != Relocs.size(); ++j)
+              if (Relocs[j].first >= Sections[SectIdx].Address + Inst.Address &&
+                  Relocs[j].first < Sections[SectIdx].Address + Inst.Address +
+                                    Inst.Size) {
+                outs() << "\t# "
+                   << MachOObj->getStringAtIndex(
+                                  UnsortedSymbols[Relocs[j].second].StringIndex)
+                   << ' ';
+                DumpAddress(UnsortedSymbols[Relocs[j].second].Value, Sections,
+                            MachOObj.get(), outs());
+              }
+            uint64_t targ = InstrAnalysis->evaluateBranch(Inst.Inst,
+                                                          Inst.Address,
+                                                          Inst.Size);
+            if (targ != -1ULL)
+              DumpAddress(targ, Sections, MachOObj.get(), outs());
+
+            outs() << '\n';
+          }
+        }
+
+        // Start a new dot file.
+        std::string Error;
+        raw_fd_ostream Out((f.getName().str() + ".dot").c_str(), Error);
+        if (!Error.empty()) {
+          errs() << "llvm-objdump: warning: " << Error << '\n';
+          continue;
+        }
+
+        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";
+      }
+    }
+  }
+}