Flush out enough of llvm-objdump’s SymbolizerSymbolLookUp() for Mach-O files to

get the literal string “Hello world” printed as a comment on the instruction
that loads the pointer to it. For now this is just for x86_64. So for object
files with relocation entries it produces things like:

	leaq	L_.str(%rip), %rax      ## literal pool for: "Hello world\n"

and similar for fully linked images like executables:

	leaq	0x4f(%rip), %rax        ## literal pool for: "Hello world\n"

Also to allow testing against darwin’s otool(1), I hooked up the existing 
-no-show-raw-insn option to the Mach-O parser code, added the new Mach-O
only -full-leading-addr option to match otool(1)'s printing of addresses and
also added the new -print-imm-hex option.

llvm-svn: 218423

llvm/test/tools/llvm-objdump/X86/macho-symbolized-disassembly.test

@@ -1,4 +1,7 @@
-// RUN: llvm-objdump -d -m %p/Inputs/hello.obj.macho-x86_64 | FileCheck %s
+// RUN: llvm-objdump -d -m -no-show-raw-insn -full-leading-addr -print-imm-hex %p/Inputs/hello.obj.macho-x86_64 | FileCheck %s -check-prefix=OBJ
+// RUN: llvm-objdump -d -m -no-show-raw-insn -full-leading-addr -print-imm-hex %p/Inputs/hello.exe.macho-x86_64 | FileCheck %s -check-prefix=EXE
 
-CHECK: leaq	L_.str(%rip), %rax
+OBJ: 0000000000000008	leaq	L_.str(%rip), %rax      ## literal pool for: "Hello world\n"
-CHECK: callq	_printf
+OBJ: 0000000000000026	callq	_printf
+
+EXE: 0000000100000f38	leaq	0x4f(%rip), %rax        ## literal pool for: "Hello world\n"

llvm/tools/llvm-objdump/MachODump.cpp

@@ -36,6 +36,7 @@
 #include "llvm/Support/GraphWriter.h"
 #include "llvm/Support/MachO.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Support/raw_ostream.h"
@@ -51,6 +52,14 @@ static cl::opt<bool>
 static cl::opt<std::string>
   DSYMFile("dsym", cl::desc("Use .dSYM file for debug info"));
 
+static cl::opt<bool>
+    FullLeadingAddr("full-leading-addr",
+                    cl::desc("Print full leading address"));
+
+static cl::opt<bool>
+    PrintImmHex("print-imm-hex",
+                cl::desc("Use hex format for immediate values"));
+
 static std::string ThumbTripleName;
 
 static const Target *GetTarget(const MachOObjectFile *MachOObj,
@@ -225,11 +234,14 @@ void llvm::DisassembleInputMachO(StringRef Filename) {
   DisassembleInputMachO2(Filename, MachOOF.get());
 }
 
+typedef DenseMap<uint64_t, StringRef> SymbolAddressMap;
+
 // The block of info used by the Symbolizer call backs.
 struct DisassembleInfo {
   bool verbose;
   MachOObjectFile *O;
   SectionRef S;
+  SymbolAddressMap *AddrMap;
 };
 
 // SymbolizerGetOpInfo() is the operand information call back function.
@@ -301,7 +313,6 @@ int SymbolizerGetOpInfo(void *DisInfo, uint64_t Pc, uint64_t Offset,
       // is the offset from the external symbol.
       if (info->O->getAnyRelocationPCRel(RE))
         op_info->Value -= Pc + Offset + Size;
-      // SymbolRef Symbol = (*info->Relocs)[Idx].second;
       StringRef SymName;
       Symbol.getName(SymName);
       const char *name = SymName.data();
@@ -343,8 +354,142 @@ int SymbolizerGetOpInfo(void *DisInfo, uint64_t Pc, uint64_t Offset,
   }
 }
 
+// GuessCstringPointer is passed the address of what might be a pointer to a
+// literal string in a cstring section.  If that address is in a cstring section
+// it returns a pointer to that string.  Else it returns nullptr.
+const char *GuessCstringPointer(uint64_t ReferenceValue,
+                                struct DisassembleInfo *info) {
+  uint32_t LoadCommandCount = info->O->getHeader().ncmds;
+  MachOObjectFile::LoadCommandInfo Load = info->O->getFirstLoadCommandInfo();
+  for (unsigned I = 0;; ++I) {
+    if (Load.C.cmd == MachO::LC_SEGMENT_64) {
+      MachO::segment_command_64 Seg = info->O->getSegment64LoadCommand(Load);
+      for (unsigned J = 0; J < Seg.nsects; ++J) {
+        MachO::section_64 Sec = info->O->getSection64(Load, J);
+        uint32_t section_type = Sec.flags & MachO::SECTION_TYPE;
+        if (section_type == MachO::S_CSTRING_LITERALS &&
+            ReferenceValue >= Sec.addr &&
+            ReferenceValue < Sec.addr + Sec.size) {
+          uint64_t sect_offset = ReferenceValue - Sec.addr;
+          uint64_t object_offset = Sec.offset + sect_offset;
+          StringRef MachOContents = info->O->getData();
+          uint64_t object_size = MachOContents.size();
+          const char *object_addr = (const char *)MachOContents.data();
+          if (object_offset < object_size) {
+            const char *name = object_addr + object_offset;
+            return name;
+          } else {
+            return nullptr;
+          }
+        }
+      }
+    } else if (Load.C.cmd == MachO::LC_SEGMENT) {
+      MachO::segment_command Seg = info->O->getSegmentLoadCommand(Load);
+      for (unsigned J = 0; J < Seg.nsects; ++J) {
+        MachO::section Sec = info->O->getSection(Load, J);
+        uint32_t section_type = Sec.flags & MachO::SECTION_TYPE;
+        if (section_type == MachO::S_CSTRING_LITERALS &&
+            ReferenceValue >= Sec.addr &&
+            ReferenceValue < Sec.addr + Sec.size) {
+          uint64_t sect_offset = ReferenceValue - Sec.addr;
+          uint64_t object_offset = Sec.offset + sect_offset;
+          StringRef MachOContents = info->O->getData();
+          uint64_t object_size = MachOContents.size();
+          const char *object_addr = (const char *)MachOContents.data();
+          if (object_offset < object_size) {
+            const char *name = object_addr + object_offset;
+            return name;
+          } else {
+            return nullptr;
+          }
+        }
+      }
+    }
+    if (I == LoadCommandCount - 1)
+      break;
+    else
+      Load = info->O->getNextLoadCommandInfo(Load);
+  }
+  return nullptr;
+}
+
+// GuessLiteralPointer returns a string which for the item in the Mach-O file
+// for the address passed in as ReferenceValue for printing as a comment with
+// the instruction and also returns the corresponding type of that item
+// indirectly through ReferenceType.
+//
+// If ReferenceValue is an address of literal cstring then a pointer to the
+// cstring is returned and ReferenceType is set to
+// LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr .
+//
+// TODO: other literals such as Objective-C CFStrings refs, Selector refs,
+// Message refs, Class refs and a Symbol address in a literal pool are yet
+// to be done here.
+const char *GuessLiteralPointer(uint64_t ReferenceValue, uint64_t ReferencePC,
+                                uint64_t *ReferenceType,
+                                struct DisassembleInfo *info) {
+  // TODO: This rouine's code is only for an x86_64 Mach-O file for now.
+  unsigned int Arch = info->O->getArch();
+  if (Arch != Triple::x86_64)
+    return nullptr;
+
+  // First see if there is an external relocation entry at the ReferencePC.
+  uint64_t sect_addr;
+  info->S.getAddress(sect_addr);
+  uint64_t sect_offset = ReferencePC - sect_addr;
+  bool reloc_found = false;
+  DataRefImpl Rel;
+  MachO::any_relocation_info RE;
+  bool isExtern = false;
+  SymbolRef Symbol;
+  for (const RelocationRef &Reloc : info->S.relocations()) {
+    uint64_t RelocOffset;
+    Reloc.getOffset(RelocOffset);
+    if (RelocOffset == sect_offset) {
+      Rel = Reloc.getRawDataRefImpl();
+      RE = info->O->getRelocation(Rel);
+      if (info->O->isRelocationScattered(RE))
+        continue;
+      isExtern = info->O->getPlainRelocationExternal(RE);
+      if (isExtern) {
+        symbol_iterator RelocSym = Reloc.getSymbol();
+        Symbol = *RelocSym;
+      }
+      reloc_found = true;
+      break;
+    }
+  }
+  // If there is an external relocation entry for a symbol in a section
+  // then used that symbol's value for the value of the reference.
+  if (reloc_found && isExtern) {
+    if (info->O->getAnyRelocationPCRel(RE)) {
+      unsigned Type = info->O->getAnyRelocationType(RE);
+      if (Type == MachO::X86_64_RELOC_SIGNED) {
+        Symbol.getAddress(ReferenceValue);
+      }
+    }
+  }
+
+  // TODO: the code to look for other literals such as Objective-C CFStrings
+  // refs, Selector refs, Message refs, Class refs will be added here.
+
+  const char *name = GuessCstringPointer(ReferenceValue, info);
+  if (name) {
+    // TODO: note when the code is added above for Selector refs and Message
+    // refs we will need check for that here and set the ReferenceType
+    // accordingly.
+    *ReferenceType = LLVMDisassembler_ReferenceType_Out_LitPool_CstrAddr;
+    return name;
+  }
+
+  // TODO: look for an indirect symbol with this ReferenceValue which is in
+  // a literal pool.
+
+  return nullptr;
+}
+
 // SymbolizerSymbolLookUp is the symbol lookup function passed when creating
-// the Symbolizer.  It looks up the SymbolValue using the info passed via the
+// the Symbolizer.  It looks up the ReferenceValue using the info passed via the
 // pointer to the struct DisassembleInfo that was passed when MCSymbolizer
 // is created and returns the symbol name that matches the ReferenceValue or
 // nullptr if none.  The ReferenceType is passed in for the IN type of
@@ -374,20 +519,89 @@ const char *SymbolizerSymbolLookUp(void *DisInfo, uint64_t ReferenceValue,
                                    uint64_t ReferencePC,
                                    const char **ReferenceName) {
   struct DisassembleInfo *info = (struct DisassembleInfo *)DisInfo;
+  // If no verbose symbolic information is wanted then just return nullptr.
+  if (info->verbose == false) {
     *ReferenceName = nullptr;
     *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
-  unsigned int Arch = info->O->getArch();
-  if (Arch == Triple::x86) {
-    return nullptr;
-  } else if (Arch == Triple::x86_64) {
-    return nullptr;
-  } else if (Arch == Triple::arm) {
-    return nullptr;
-  } else if (Arch == Triple::aarch64) {
-    return nullptr;
-  } else {
     return nullptr;
   }
+
+  const char *SymbolName = nullptr;
+  StringRef name = info->AddrMap->lookup(ReferenceValue);
+  if (!name.empty())
+    SymbolName = name.data();
+
+  if (*ReferenceType == LLVMDisassembler_ReferenceType_In_PCrel_Load) {
+    *ReferenceName = GuessLiteralPointer(ReferenceValue, ReferencePC,
+                                         ReferenceType, info);
+    if (*ReferenceName == nullptr)
+      *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
+  // TODO: other types of references to be added.
+  } else {
+    *ReferenceName = nullptr;
+    *ReferenceType = LLVMDisassembler_ReferenceType_InOut_None;
+  }
+
+  return SymbolName;
+}
+
+//
+// This is the memory object used by DisAsm->getInstruction() which has its
+// BasePC.  This then allows the 'address' parameter to getInstruction() to
+// be the actual PC of the instruction.  Then when a branch dispacement is
+// added to the PC of an instruction, the 'ReferenceValue' passed to the
+// SymbolizerSymbolLookUp() routine is the correct target addresses.  As in
+// the case of a fully linked Mach-O file where a section being disassembled
+// generally not linked at address zero.
+//
+class DisasmMemoryObject : public MemoryObject {
+  uint8_t *Bytes;
+  uint64_t Size;
+  uint64_t BasePC;
+public:
+  DisasmMemoryObject(uint8_t *bytes, uint64_t size, uint64_t basePC) :
+                     Bytes(bytes), Size(size), BasePC(basePC) {}
+
+  uint64_t getBase() const override { return BasePC; }
+  uint64_t getExtent() const override { return Size; }
+
+  int readByte(uint64_t Addr, uint8_t *Byte) const override {
+    if (Addr - BasePC >= Size)
+      return -1;
+    *Byte = Bytes[Addr - BasePC];
+    return 0;
+  }
+};
+
+/// \brief Emits the comments that are stored in the CommentStream.
+/// Each comment in the CommentStream must end with a newline.
+static void emitComments(raw_svector_ostream &CommentStream,
+                         SmallString<128> &CommentsToEmit,
+                         formatted_raw_ostream &FormattedOS,
+                         const MCAsmInfo &MAI) {
+  // Flush the stream before taking its content.
+  CommentStream.flush();
+  StringRef Comments = CommentsToEmit.str();
+  // Get the default information for printing a comment.
+  const char *CommentBegin = MAI.getCommentString();
+  unsigned CommentColumn = MAI.getCommentColumn();
+  bool IsFirst = true;
+  while (!Comments.empty()) {
+    if (!IsFirst)
+      FormattedOS << '\n';
+    // Emit a line of comments.
+    FormattedOS.PadToColumn(CommentColumn);
+    size_t Position = Comments.find('\n');
+    FormattedOS << CommentBegin << ' ' << Comments.substr(0, Position);
+    // Move after the newline character.
+    Comments = Comments.substr(Position + 1);
+    IsFirst = false;
+  }
+  FormattedOS.flush();
+
+  // Tell the comment stream that the vector changed underneath it.
+  CommentsToEmit.clear();
+  CommentStream.resync();
 }
 
 static void DisassembleInputMachO2(StringRef Filename,
@@ -445,6 +659,12 @@ static void DisassembleInputMachO2(StringRef Filename,
   int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
   std::unique_ptr<MCInstPrinter> IP(TheTarget->createMCInstPrinter(
       AsmPrinterVariant, *AsmInfo, *InstrInfo, *MRI, *STI));
+  // Set the display preference for hex vs. decimal immediates.
+  IP->setPrintImmHex(PrintImmHex);
+  // Comment stream and backing vector.
+  SmallString<128> CommentsToEmit;
+  raw_svector_ostream CommentStream(CommentsToEmit);
+  IP->setCommentStream(CommentStream);
 
   if (!InstrAnalysis || !AsmInfo || !STI || !DisAsm || !IP) {
     errs() << "error: couldn't initialize disassembler for target "
@@ -467,11 +687,13 @@ static void DisassembleInputMachO2(StringRef Filename,
         ThumbTarget->createMCSubtargetInfo(ThumbTripleName, MCPU, FeaturesStr));
     ThumbCtx.reset(new MCContext(ThumbAsmInfo.get(), ThumbMRI.get(), nullptr));
     ThumbDisAsm.reset(ThumbTarget->createMCDisassembler(*ThumbSTI, *ThumbCtx));
-// TODO: add MCSymbolizer here for the ThumbTarget like above for TheTarget.
+    // TODO: add MCSymbolizer here for the ThumbTarget like above for TheTarget.
     int ThumbAsmPrinterVariant = ThumbAsmInfo->getAssemblerDialect();
     ThumbIP.reset(ThumbTarget->createMCInstPrinter(
         ThumbAsmPrinterVariant, *ThumbAsmInfo, *ThumbInstrInfo, *ThumbMRI,
         *ThumbSTI));
+    // Set the display preference for hex vs. decimal immediates.
+    ThumbIP->setPrintImmHex(PrintImmHex);
   }
 
   if (ThumbTarget && (!ThumbInstrAnalysis || !ThumbAsmInfo || !ThumbSTI ||
@@ -564,7 +786,10 @@ static void DisassembleInputMachO2(StringRef Filename,
 
     StringRef Bytes;
     Sections[SectIdx].getContents(Bytes);
-    StringRefMemoryObject memoryObject(Bytes);
+    uint64_t SectAddress = 0;
+    Sections[SectIdx].getAddress(SectAddress);
+    DisasmMemoryObject MemoryObject((uint8_t *)Bytes.data(), Bytes.size(),
+                                    SectAddress);
     bool symbolTableWorked = false;
 
     // Parse relocations.
@@ -581,10 +806,26 @@ static void DisassembleInputMachO2(StringRef Filename,
     }
     array_pod_sort(Relocs.begin(), Relocs.end());
 
+    // Create a map of symbol addresses to symbol names for use by
+    // the SymbolizerSymbolLookUp() routine.
+    SymbolAddressMap AddrMap;
+    for (const SymbolRef &Symbol : MachOOF->symbols()) {
+      SymbolRef::Type ST;
+      Symbol.getType(ST);
+      if (ST == SymbolRef::ST_Function || ST == SymbolRef::ST_Data ||
+          ST == SymbolRef::ST_Other) {
+        uint64_t Address;
+        Symbol.getAddress(Address);
+        StringRef SymName;
+        Symbol.getName(SymName);
+        AddrMap[Address] = SymName;
+      }
+    }
     // Set up the block of info used by the Symbolizer call backs.
     SymbolizerInfo.verbose = true;
     SymbolizerInfo.O = MachOOF;
     SymbolizerInfo.S = Sections[SectIdx];
+    SymbolizerInfo.AddrMap = &AddrMap;
 
     // Disassemble symbol by symbol.
     for (unsigned SymIdx = 0; SymIdx != Symbols.size(); SymIdx++) {
@@ -643,14 +884,22 @@ static void DisassembleInputMachO2(StringRef Filename,
       for (uint64_t Index = Start; Index < End; Index += Size) {
         MCInst Inst;
 
-        uint64_t SectAddress = 0;
+        uint64_t PC = SectAddress + Index;
-        Sections[SectIdx].getAddress(SectAddress);
+        if (FullLeadingAddr) {
-        outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
+          if (MachOOF->is64Bit())
+            outs() << format("%016" PRIx64, PC);
+           else
+            outs() << format("%08" PRIx64, PC);
+        } else {
+          outs() << format("%8" PRIx64 ":", PC);
+        }
+        if (!NoShowRawInsn)
+          outs() << "\t";
 
         // 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.push_back(std::make_pair(PC, DiceRef()));
         dice_table_iterator DTI = std::search(Dices.begin(), Dices.end(),
                                               Dice.begin(), Dice.end(),
                                               compareDiceTableEntries);
@@ -664,24 +913,33 @@ static void DisassembleInputMachO2(StringRef Filename,
           continue;
         }
 
+        SmallVector<char, 64> AnnotationsBytes;
+        raw_svector_ostream Annotations(AnnotationsBytes);
+
         bool gotInst;
         if (isThumb)
-          gotInst = ThumbDisAsm->getInstruction(Inst, Size, memoryObject, Index,
+          gotInst = ThumbDisAsm->getInstruction(Inst, Size, MemoryObject, PC,
-                                     DebugOut, nulls());
+                                                DebugOut, Annotations);
         else
-          gotInst = DisAsm->getInstruction(Inst, Size, memoryObject, Index,
+          gotInst = DisAsm->getInstruction(Inst, Size, MemoryObject, PC,
-                                     DebugOut, nulls());
+                                           DebugOut, Annotations);
         if (gotInst) {
+          if (!NoShowRawInsn) {
             DumpBytes(StringRef(Bytes.data() + Index, Size));
+          }
+          formatted_raw_ostream FormattedOS(outs());
+          Annotations.flush();
+          StringRef AnnotationsStr = Annotations.str();
           if (isThumb)
-            ThumbIP->printInst(&Inst, outs(), "");
+            ThumbIP->printInst(&Inst, FormattedOS, AnnotationsStr);
           else
-            IP->printInst(&Inst, outs(), "");
+            IP->printInst(&Inst, FormattedOS, AnnotationsStr);
+          emitComments(CommentStream, CommentsToEmit, FormattedOS, *AsmInfo);
 
           // Print debug info.
           if (diContext) {
             DILineInfo dli =
-              diContext->getLineInfoForAddress(SectAddress + Index);
+              diContext->getLineInfoForAddress(PC);
             // Print valid line info if it changed.
             if (dli != lastLine && dli.Line != 0)
               outs() << "\t## " << dli.FileName << ':' << dli.Line << ':'
@@ -706,10 +964,21 @@ static void DisassembleInputMachO2(StringRef Filename,
       for (uint64_t Index = 0; Index < SectSize; Index += InstSize) {
         MCInst Inst;
 
-        if (DisAsm->getInstruction(Inst, InstSize, memoryObject, Index,
+        uint64_t PC = SectAddress + Index;
+        if (DisAsm->getInstruction(Inst, InstSize, MemoryObject, PC,
                                    DebugOut, nulls())) {
-          outs() << format("%8" PRIx64 ":\t", SectAddress + Index);
+          if (FullLeadingAddr) {
+            if (MachOOF->is64Bit())
+              outs() << format("%016" PRIx64, PC);
+             else
+              outs() << format("%08" PRIx64, PC);
+          } else {
+            outs() << format("%8" PRIx64 ":", PC);
+          }
+          if (!NoShowRawInsn) {
+            outs() << "\t";
             DumpBytes(StringRef(Bytes.data() + Index, InstSize));
+          }
           IP->printInst(&Inst, outs(), "");
           outs() << "\n";
         } else {

llvm/tools/llvm-objdump/llvm-objdump.cpp

@@ -128,9 +128,10 @@ llvm::MAttrs("mattr",
   cl::desc("Target specific attributes"),
   cl::value_desc("a1,+a2,-a3,..."));
 
-static cl::opt<bool>
+cl::opt<bool>
-NoShowRawInsn("no-show-raw-insn", cl::desc("When disassembling instructions, "
+llvm::NoShowRawInsn("no-show-raw-insn", cl::desc("When disassembling "
-                                           "do not print the instruction bytes."));
+                                                 "instructions, do not print "
+                                                 "the instruction bytes."));
 
 static cl::opt<bool>
 UnwindInfo("unwind-info", cl::desc("Display unwind information"));

llvm/tools/llvm-objdump/llvm-objdump.h

@@ -27,6 +27,7 @@ extern cl::opt<std::string> TripleName;
 extern cl::opt<std::string> ArchName;
 extern cl::opt<std::string> MCPU;
 extern cl::list<std::string> MAttrs;
+extern cl::opt<bool> NoShowRawInsn;
 
 // Various helper functions.
 bool error(std::error_code ec);