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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/Error.h"
     31 #include "llvm/Support/FileSystem.h"
     32 #include "llvm/Support/FormattedStream.h"
     33 #include "llvm/Support/ManagedStatic.h"
     34 #include "llvm/Support/MemoryBuffer.h"
     35 #include "llvm/Support/PrettyStackTrace.h"
     36 #include "llvm/Support/Signals.h"
     37 #include "llvm/Support/ToolOutputFile.h"
     38 #include <system_error>
     39 using namespace llvm;
     40 
     41 static cl::opt<std::string>
     42 InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
     43 
     44 static cl::opt<std::string>
     45 OutputFilename("o", cl::desc("Override output filename"),
     46                cl::value_desc("filename"));
     47 
     48 static cl::opt<bool>
     49 Force("f", cl::desc("Enable binary output on terminals"));
     50 
     51 static cl::opt<bool>
     52 DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
     53 
     54 static cl::opt<bool>
     55 ShowAnnotations("show-annotations",
     56                 cl::desc("Add informational comments to the .ll file"));
     57 
     58 static cl::opt<bool> PreserveAssemblyUseListOrder(
     59     "preserve-ll-uselistorder",
     60     cl::desc("Preserve use-list order when writing LLVM assembly."),
     61     cl::init(false), cl::Hidden);
     62 
     63 static cl::opt<bool>
     64     MaterializeMetadata("materialize-metadata",
     65                         cl::desc("Load module without materializing metadata, "
     66                                  "then materialize only the metadata"));
     67 
     68 namespace {
     69 
     70 static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
     71   OS << DL.getLine() << ":" << DL.getCol();
     72   if (DILocation *IDL = DL.getInlinedAt()) {
     73     OS << "@";
     74     printDebugLoc(IDL, OS);
     75   }
     76 }
     77 class CommentWriter : public AssemblyAnnotationWriter {
     78 public:
     79   void emitFunctionAnnot(const Function *F,
     80                          formatted_raw_ostream &OS) override {
     81     OS << "; [#uses=" << F->getNumUses() << ']';  // Output # uses
     82     OS << '\n';
     83   }
     84   void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
     85     bool Padded = false;
     86     if (!V.getType()->isVoidTy()) {
     87       OS.PadToColumn(50);
     88       Padded = true;
     89       // Output # uses and type
     90       OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]";
     91     }
     92     if (const Instruction *I = dyn_cast<Instruction>(&V)) {
     93       if (const DebugLoc &DL = I->getDebugLoc()) {
     94         if (!Padded) {
     95           OS.PadToColumn(50);
     96           Padded = true;
     97           OS << ";";
     98         }
     99         OS << " [debug line = ";
    100         printDebugLoc(DL,OS);
    101         OS << "]";
    102       }
    103       if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
    104         if (!Padded) {
    105           OS.PadToColumn(50);
    106           OS << ";";
    107         }
    108         OS << " [debug variable = " << DDI->getVariable()->getName() << "]";
    109       }
    110       else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
    111         if (!Padded) {
    112           OS.PadToColumn(50);
    113           OS << ";";
    114         }
    115         OS << " [debug variable = " << DVI->getVariable()->getName() << "]";
    116       }
    117     }
    118   }
    119 };
    120 
    121 } // end anon namespace
    122 
    123 static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
    124   raw_ostream &OS = errs();
    125   OS << (char *)Context << ": ";
    126   switch (DI.getSeverity()) {
    127   case DS_Error: OS << "error: "; break;
    128   case DS_Warning: OS << "warning: "; break;
    129   case DS_Remark: OS << "remark: "; break;
    130   case DS_Note: OS << "note: "; break;
    131   }
    132 
    133   DiagnosticPrinterRawOStream DP(OS);
    134   DI.print(DP);
    135   OS << '\n';
    136 
    137   if (DI.getSeverity() == DS_Error)
    138     exit(1);
    139 }
    140 
    141 static Expected<std::unique_ptr<Module>> openInputFile(LLVMContext &Context) {
    142   if (MaterializeMetadata) {
    143     ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
    144         MemoryBuffer::getFileOrSTDIN(InputFilename);
    145     if (!MBOrErr)
    146       return errorCodeToError(MBOrErr.getError());
    147     ErrorOr<std::unique_ptr<Module>> MOrErr =
    148         getLazyBitcodeModule(std::move(*MBOrErr), Context,
    149                              /*ShouldLazyLoadMetadata=*/true);
    150     if (!MOrErr)
    151       return errorCodeToError(MOrErr.getError());
    152     (*MOrErr)->materializeMetadata();
    153     return std::move(*MOrErr);
    154   } else {
    155     std::string ErrorMessage;
    156     std::unique_ptr<DataStreamer> Streamer =
    157         getDataFileStreamer(InputFilename, &ErrorMessage);
    158     if (!Streamer)
    159       return make_error<StringError>(ErrorMessage, inconvertibleErrorCode());
    160     std::string DisplayFilename;
    161     if (InputFilename == "-")
    162       DisplayFilename = "<stdin>";
    163     else
    164       DisplayFilename = InputFilename;
    165     ErrorOr<std::unique_ptr<Module>> MOrErr =
    166         getStreamedBitcodeModule(DisplayFilename, std::move(Streamer), Context);
    167     (*MOrErr)->materializeAll();
    168     return std::move(*MOrErr);
    169   }
    170 }
    171 
    172 int main(int argc, char **argv) {
    173   // Print a stack trace if we signal out.
    174   sys::PrintStackTraceOnErrorSignal(argv[0]);
    175   PrettyStackTraceProgram X(argc, argv);
    176 
    177   LLVMContext Context;
    178   llvm_shutdown_obj Y;  // Call llvm_shutdown() on exit.
    179 
    180   Context.setDiagnosticHandler(diagnosticHandler, argv[0]);
    181 
    182   cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
    183 
    184   Expected<std::unique_ptr<Module>> MOrErr = openInputFile(Context);
    185   if (!MOrErr) {
    186     handleAllErrors(MOrErr.takeError(), [&](ErrorInfoBase &EIB) {
    187       errs() << argv[0] << ": ";
    188       EIB.log(errs());
    189       errs() << '\n';
    190     });
    191     return 1;
    192   }
    193   std::unique_ptr<Module> M = std::move(*MOrErr);
    194 
    195   // Just use stdout.  We won't actually print anything on it.
    196   if (DontPrint)
    197     OutputFilename = "-";
    198 
    199   if (OutputFilename.empty()) { // Unspecified output, infer it.
    200     if (InputFilename == "-") {
    201       OutputFilename = "-";
    202     } else {
    203       StringRef IFN = InputFilename;
    204       OutputFilename = (IFN.endswith(".bc") ? IFN.drop_back(3) : IFN).str();
    205       OutputFilename += ".ll";
    206     }
    207   }
    208 
    209   std::error_code EC;
    210   std::unique_ptr<tool_output_file> Out(
    211       new tool_output_file(OutputFilename, EC, sys::fs::F_None));
    212   if (EC) {
    213     errs() << EC.message() << '\n';
    214     return 1;
    215   }
    216 
    217   std::unique_ptr<AssemblyAnnotationWriter> Annotator;
    218   if (ShowAnnotations)
    219     Annotator.reset(new CommentWriter());
    220 
    221   // All that llvm-dis does is write the assembly to a file.
    222   if (!DontPrint)
    223     M->print(Out->os(), Annotator.get(), PreserveAssemblyUseListOrder);
    224 
    225   // Declare success.
    226   Out->keep();
    227 
    228   return 0;
    229 }
    230