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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/IR/LLVMContext.h"
     20 #include "llvm/Bitcode/ReaderWriter.h"
     21 #include "llvm/IR/AssemblyAnnotationWriter.h"
     22 #include "llvm/IR/DebugInfo.h"
     23 #include "llvm/IR/IntrinsicInst.h"
     24 #include "llvm/IR/Module.h"
     25 #include "llvm/IR/Type.h"
     26 #include "llvm/Support/CommandLine.h"
     27 #include "llvm/Support/DataStream.h"
     28 #include "llvm/Support/FileSystem.h"
     29 #include "llvm/Support/FormattedStream.h"
     30 #include "llvm/Support/ManagedStatic.h"
     31 #include "llvm/Support/MemoryBuffer.h"
     32 #include "llvm/Support/PrettyStackTrace.h"
     33 #include "llvm/Support/Signals.h"
     34 #include "llvm/Support/ToolOutputFile.h"
     35 #include <system_error>
     36 using namespace llvm;
     37 
     38 static cl::opt<std::string>
     39 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
     40 
     41 static cl::opt<std::string>
     42 OutputFilename("o", cl::desc("Override output filename"),
     43                cl::value_desc("filename"));
     44 
     45 static cl::opt<bool>
     46 Force("f", cl::desc("Enable binary output on terminals"));
     47 
     48 static cl::opt<bool>
     49 DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
     50 
     51 static cl::opt<bool>
     52 ShowAnnotations("show-annotations",
     53                 cl::desc("Add informational comments to the .ll file"));
     54 
     55 namespace {
     56 
     57 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
     58   OS << DL.getLine() << ":" << DL.getCol();
     59   if (MDNode *N = DL.getInlinedAt(getGlobalContext())) {
     60     DebugLoc IDL = DebugLoc::getFromDILocation(N);
     61     if (!IDL.isUnknown()) {
     62       OS << "@";
     63       printDebugLoc(IDL,OS);
     64     }
     65   }
     66 }
     67 class CommentWriter : public AssemblyAnnotationWriter {
     68 public:
     69   void emitFunctionAnnot(const Function *F,
     70                          formatted_raw_ostream &OS) override {
     71     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
     72     OS << '\n';
     73   }
     74   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
     75     bool Padded = false;
     76     if (!V.getType()->isVoidTy()) {
     77       OS.PadToColumn(50);
     78       Padded = true;
     79       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";  // Output # uses and type
     80     }
     81     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
     82       const DebugLoc &DL = I->getDebugLoc();
     83       if (!DL.isUnknown()) {
     84         if (!Padded) {
     85           OS.PadToColumn(50);
     86           Padded = true;
     87           OS << ";";
     88         }
     89         OS << " [debug line = ";
     90         printDebugLoc(DL,OS);
     91         OS << "]";
     92       }
     93       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
     94         DIVariable Var(DDI->getVariable());
     95         if (!Padded) {
     96           OS.PadToColumn(50);
     97           OS << ";";
     98         }
     99         OS << " [debug variable = " << Var.getName() << "]";
    100       }
    101       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
    102         DIVariable Var(DVI->getVariable());
    103         if (!Padded) {
    104           OS.PadToColumn(50);
    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::unique_ptr<Module> M;
    128 
    129   // Use the bitcode streaming interface
    130   DataStreamer *streamer = getDataFileStreamer(InputFilename, &ErrorMessage);
    131   if (streamer) {
    132     std::string DisplayFilename;
    133     if (InputFilename == "-")
    134       DisplayFilename = "<stdin>";
    135     else
    136       DisplayFilename = InputFilename;
    137     M.reset(getStreamedBitcodeModule(DisplayFilename, streamer, Context,
    138                                      &ErrorMessage));
    139     if(M.get()) {
    140       if (std::error_code EC = M->materializeAllPermanently()) {
    141         ErrorMessage = EC.message();
    142         M.reset();
    143       }
    144     }
    145   }
    146 
    147   if (!M.get()) {
    148     errs() << argv[0] << ": ";
    149     if (ErrorMessage.size())
    150       errs() << ErrorMessage << "\n";
    151     else
    152       errs() << "bitcode didn't read correctly.\n";
    153     return 1;
    154   }
    155 
    156   // Just use stdout.  We won't actually print anything on it.
    157   if (DontPrint)
    158     OutputFilename = "-";
    159 
    160   if (OutputFilename.empty()) { // Unspecified output, infer it.
    161     if (InputFilename == "-") {
    162       OutputFilename = "-";
    163     } else {
    164       const std::string &IFN = InputFilename;
    165       int Len = IFN.length();
    166       // If the source ends in .bc, strip it off.
    167       if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c')
    168         OutputFilename = std::string(IFN.begin(), IFN.end()-3)+".ll";
    169       else
    170         OutputFilename = IFN+".ll";
    171     }
    172   }
    173 
    174   std::string ErrorInfo;
    175   std::unique_ptr<tool_output_file> Out(
    176       new tool_output_file(OutputFilename.c_str(), ErrorInfo, sys::fs::F_None));
    177   if (!ErrorInfo.empty()) {
    178     errs() << ErrorInfo << '\n';
    179     return 1;
    180   }
    181 
    182   std::unique_ptr<AssemblyAnnotationWriter> Annotator;
    183   if (ShowAnnotations)
    184     Annotator.reset(new CommentWriter());
    185 
    186   // All that llvm-dis does is write the assembly to a file.
    187   if (!DontPrint)
    188     M->print(Out->os(), Annotator.get());
    189 
    190   // Declare success.
    191   Out->keep();
    192 
    193   return 0;
    194 }
    195