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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/DiagnosticInfo.h"
     24 #include "llvm/IR/DiagnosticPrinter.h"
     25 #include "llvm/IR/IntrinsicInst.h"
     26 #include "llvm/IR/Module.h"
     27 #include "llvm/IR/Type.h"
     28 #include "llvm/Support/CommandLine.h"
     29 #include "llvm/Support/DataStream.h"
     30 #include "llvm/Support/FileSystem.h"
     31 #include "llvm/Support/FormattedStream.h"
     32 #include "llvm/Support/ManagedStatic.h"
     33 #include "llvm/Support/MemoryBuffer.h"
     34 #include "llvm/Support/PrettyStackTrace.h"
     35 #include "llvm/Support/Signals.h"
     36 #include "llvm/Support/ToolOutputFile.h"
     37 #include <system_error>
     38 using namespace llvm;
     39 
     40 static cl::opt<std::string>
     41 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
     42 
     43 static cl::opt<std::string>
     44 OutputFilename("o", cl::desc("Override output filename"),
     45                cl::value_desc("filename"));
     46 
     47 static cl::opt<bool>
     48 Force("f", cl::desc("Enable binary output on terminals"));
     49 
     50 static cl::opt<bool>
     51 DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
     52 
     53 static cl::opt<bool>
     54 ShowAnnotations("show-annotations",
     55                 cl::desc("Add informational comments to the .ll file"));
     56 
     57 static cl::opt<bool> PreserveAssemblyUseListOrder(
     58     "preserve-ll-uselistorder",
     59     cl::desc("Preserve use-list order when writing LLVM assembly."),
     60     cl::init(false), cl::Hidden);
     61 
     62 namespace {
     63 
     64 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
     65   OS << DL.getLine() << ":" << DL.getCol();
     66   if (DILocation *IDL = DL.getInlinedAt()) {
     67     OS << "@";
     68     printDebugLoc(IDL, OS);
     69   }
     70 }
     71 class CommentWriter : public AssemblyAnnotationWriter {
     72 public:
     73   void emitFunctionAnnot(const Function *F,
     74                          formatted_raw_ostream &OS) override {
     75     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
     76     OS << '\n';
     77   }
     78   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
     79     bool Padded = false;
     80     if (!V.getType()->isVoidTy()) {
     81       OS.PadToColumn(50);
     82       Padded = true;
     83       // Output # uses and type
     84       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";
     85     }
     86     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
     87       if (const DebugLoc &DL = I->getDebugLoc()) {
     88         if (!Padded) {
     89           OS.PadToColumn(50);
     90           Padded = true;
     91           OS << ";";
     92         }
     93         OS << " [debug line = ";
     94         printDebugLoc(DL,OS);
     95         OS << "]";
     96       }
     97       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
     98         if (!Padded) {
     99           OS.PadToColumn(50);
    100           OS << ";";
    101         }
    102         OS << " [debug variable = " << DDI->getVariable()->getName() << "]";
    103       }
    104       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
    105         if (!Padded) {
    106           OS.PadToColumn(50);
    107           OS << ";";
    108         }
    109         OS << " [debug variable = " << DVI->getVariable()->getName() << "]";
    110       }
    111     }
    112   }
    113 };
    114 
    115 } // end anon namespace
    116 
    117 static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
    118   raw_ostream &OS = errs();
    119   OS << (char *)Context << ": ";
    120   switch (DI.getSeverity()) {
    121   case DS_Error: OS << "error: "; break;
    122   case DS_Warning: OS << "warning: "; break;
    123   case DS_Remark: OS << "remark: "; break;
    124   case DS_Note: OS << "note: "; break;
    125   }
    126 
    127   DiagnosticPrinterRawOStream DP(OS);
    128   DI.print(DP);
    129   OS << '\n';
    130 
    131   if (DI.getSeverity() == DS_Error)
    132     exit(1);
    133 }
    134 
    135 int main(int argc, char **argv) {
    136   // Print a stack trace if we signal out.
    137   sys::PrintStackTraceOnErrorSignal();
    138   PrettyStackTraceProgram X(argc, argv);
    139 
    140   LLVMContext &Context = getGlobalContext();
    141   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    142 
    143   Context.setDiagnosticHandler(diagnosticHandler, argv[0]);
    144 
    145   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
    146 
    147   std::string ErrorMessage;
    148   std::unique_ptr<Module> M;
    149 
    150   // Use the bitcode streaming interface
    151   std::unique_ptr<DataStreamer> Streamer =
    152       getDataFileStreamer(InputFilename, &ErrorMessage);
    153   if (Streamer) {
    154     std::string DisplayFilename;
    155     if (InputFilename == "-")
    156       DisplayFilename = "<stdin>";
    157     else
    158       DisplayFilename = InputFilename;
    159     ErrorOr<std::unique_ptr<Module>> MOrErr =
    160         getStreamedBitcodeModule(DisplayFilename, std::move(Streamer), Context);
    161     M = std::move(*MOrErr);
    162     M->materializeAll();
    163   } else {
    164     errs() << argv[0] << ": " << ErrorMessage << '\n';
    165     return 1;
    166   }
    167 
    168   // Just use stdout.  We won't actually print anything on it.
    169   if (DontPrint)
    170     OutputFilename = "-";
    171 
    172   if (OutputFilename.empty()) { // Unspecified output, infer it.
    173     if (InputFilename == "-") {
    174       OutputFilename = "-";
    175     } else {
    176       StringRef IFN = InputFilename;
    177       OutputFilename = (IFN.endswith(".bc") ? IFN.drop_back(3) : IFN).str();
    178       OutputFilename += ".ll";
    179     }
    180   }
    181 
    182   std::error_code EC;
    183   std::unique_ptr<tool_output_file> Out(
    184       new tool_output_file(OutputFilename, EC, sys::fs::F_None));
    185   if (EC) {
    186     errs() << EC.message() << '\n';
    187     return 1;
    188   }
    189 
    190   std::unique_ptr<AssemblyAnnotationWriter> Annotator;
    191   if (ShowAnnotations)
    192     Annotator.reset(new CommentWriter());
    193 
    194   // All that llvm-dis does is write the assembly to a file.
    195   if (!DontPrint)
    196     M->print(Out->os(), Annotator.get(), PreserveAssemblyUseListOrder);
    197 
    198   // Declare success.
    199   Out->keep();
    200 
    201   return 0;
    202 }
    203