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      1 //===-- llvm-dis.cpp - The low-level LLVM disassembler --------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This utility may be invoked in the following manner:
     11 //  llvm-dis [options]      - Read LLVM bitcode from stdin, write asm to stdout
     12 //  llvm-dis [options] x.bc - Read LLVM bitcode from the x.bc file, write asm
     13 //                            to the x.ll file.
     14 //  Options:
     15 //      --help   - Output information about command line switches
     16 //
     17 //===----------------------------------------------------------------------===//
     18 
     19 #include "llvm/LLVMContext.h"
     20 #include "llvm/Module.h"
     21 #include "llvm/Type.h"
     22 #include "llvm/IntrinsicInst.h"
     23 #include "llvm/Bitcode/ReaderWriter.h"
     24 #include "llvm/Analysis/DebugInfo.h"
     25 #include "llvm/Assembly/AssemblyAnnotationWriter.h"
     26 #include "llvm/Support/CommandLine.h"
     27 #include "llvm/Support/FormattedStream.h"
     28 #include "llvm/Support/ManagedStatic.h"
     29 #include "llvm/Support/MemoryBuffer.h"
     30 #include "llvm/Support/PrettyStackTrace.h"
     31 #include "llvm/Support/ToolOutputFile.h"
     32 #include "llvm/Support/Signals.h"
     33 #include "llvm/Support/system_error.h"
     34 using namespace llvm;
     35 
     36 static cl::opt<std::string>
     37 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
     38 
     39 static cl::opt<std::string>
     40 OutputFilename("o", cl::desc("Override output filename"),
     41                cl::value_desc("filename"));
     42 
     43 static cl::opt<bool>
     44 Force("f", cl::desc("Enable binary output on terminals"));
     45 
     46 static cl::opt<bool>
     47 DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
     48 
     49 static cl::opt<bool>
     50 ShowAnnotations("show-annotations",
     51                 cl::desc("Add informational comments to the .ll file"));
     52 
     53 namespace {
     54 
     55 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
     56   OS << DL.getLine() << ":" << DL.getCol();
     57   if (MDNode *N = DL.getInlinedAt(getGlobalContext())) {
     58     DebugLoc IDL = DebugLoc::getFromDILocation(N);
     59     if (!IDL.isUnknown()) {
     60       OS << "@";
     61       printDebugLoc(IDL,OS);
     62     }
     63   }
     64 }
     65 class CommentWriter : public AssemblyAnnotationWriter {
     66 public:
     67   void emitFunctionAnnot(const Function *F,
     68                          formatted_raw_ostream &OS) {
     69     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
     70     OS << '\n';
     71   }
     72   void printInfoComment(const Value &V, formatted_raw_ostream &OS) {
     73     bool Padded = false;
     74     if (!V.getType()->isVoidTy()) {
     75       OS.PadToColumn(50);
     76       Padded = true;
     77       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";  // Output # uses and type
     78     }
     79     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
     80       const DebugLoc &DL = I->getDebugLoc();
     81       if (!DL.isUnknown()) {
     82         if (!Padded) {
     83           OS.PadToColumn(50);
     84           Padded = true;
     85           OS << ";";
     86         }
     87         OS << " [debug line = ";
     88         printDebugLoc(DL,OS);
     89         OS << "]";
     90       }
     91       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
     92         DIVariable Var(DDI->getVariable());
     93         if (!Padded) {
     94           OS.PadToColumn(50);
     95           Padded = true;
     96           OS << ";";
     97         }
     98         OS << " [debug variable = " << Var.getName() << "]";
     99       }
    100       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
    101         DIVariable Var(DVI->getVariable());
    102         if (!Padded) {
    103           OS.PadToColumn(50);
    104           Padded = true;
    105           OS << ";";
    106         }
    107         OS << " [debug variable = " << Var.getName() << "]";
    108       }
    109     }
    110   }
    111 };
    112 
    113 } // end anon namespace
    114 
    115 int main(int argc, char **argv) {
    116   // Print a stack trace if we signal out.
    117   sys::PrintStackTraceOnErrorSignal();
    118   PrettyStackTraceProgram X(argc, argv);
    119 
    120   LLVMContext &Context = getGlobalContext();
    121   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    122 
    123 
    124   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
    125 
    126   std::string ErrorMessage;
    127   std::auto_ptr<Module> M;
    128 
    129   {
    130     OwningPtr<MemoryBuffer> BufferPtr;
    131     if (error_code ec = MemoryBuffer::getFileOrSTDIN(InputFilename, BufferPtr))
    132       ErrorMessage = ec.message();
    133     else
    134       M.reset(ParseBitcodeFile(BufferPtr.get(), Context, &ErrorMessage));
    135   }
    136 
    137   if (M.get() == 0) {
    138     errs() << argv[0] << ": ";
    139     if (ErrorMessage.size())
    140       errs() << ErrorMessage << "\n";
    141     else
    142       errs() << "bitcode didn't read correctly.\n";
    143     return 1;
    144   }
    145 
    146   // Just use stdout.  We won't actually print anything on it.
    147   if (DontPrint)
    148     OutputFilename = "-";
    149 
    150   if (OutputFilename.empty()) { // Unspecified output, infer it.
    151     if (InputFilename == "-") {
    152       OutputFilename = "-";
    153     } else {
    154       const std::string &IFN = InputFilename;
    155       int Len = IFN.length();
    156       // If the source ends in .bc, strip it off.
    157       if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c')
    158         OutputFilename = std::string(IFN.begin(), IFN.end()-3)+".ll";
    159       else
    160         OutputFilename = IFN+".ll";
    161     }
    162   }
    163 
    164   std::string ErrorInfo;
    165   OwningPtr<tool_output_file>
    166   Out(new tool_output_file(OutputFilename.c_str(), ErrorInfo,
    167                            raw_fd_ostream::F_Binary));
    168   if (!ErrorInfo.empty()) {
    169     errs() << ErrorInfo << '\n';
    170     return 1;
    171   }
    172 
    173   OwningPtr<AssemblyAnnotationWriter> Annotator;
    174   if (ShowAnnotations)
    175     Annotator.reset(new CommentWriter());
    176 
    177   // All that llvm-dis does is write the assembly to a file.
    178   if (!DontPrint)
    179     M->print(Out->os(), Annotator.get());
    180 
    181   // Declare success.
    182   Out->keep();
    183 
    184   return 0;
    185 }
    186 
    187