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      1 //===--- llvm-as.cpp - The low-level LLVM assembler -----------------------===//
      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-as --help         - Output information about command line switches
     12 //   llvm-as [options]      - Read LLVM asm from stdin, write bitcode to stdout
     13 //   llvm-as [options] x.ll - Read LLVM asm from the x.ll file, write bitcode
     14 //                            to the x.bc file.
     15 //
     16 //===----------------------------------------------------------------------===//
     17 
     18 #include "llvm/AsmParser/Parser.h"
     19 #include "llvm/Bitcode/ReaderWriter.h"
     20 #include "llvm/IR/LLVMContext.h"
     21 #include "llvm/IR/Module.h"
     22 #include "llvm/IR/Verifier.h"
     23 #include "llvm/Support/CommandLine.h"
     24 #include "llvm/Support/FileSystem.h"
     25 #include "llvm/Support/ManagedStatic.h"
     26 #include "llvm/Support/PrettyStackTrace.h"
     27 #include "llvm/Support/Signals.h"
     28 #include "llvm/Support/SourceMgr.h"
     29 #include "llvm/Support/SystemUtils.h"
     30 #include "llvm/Support/ToolOutputFile.h"
     31 #include <memory>
     32 using namespace llvm;
     33 
     34 static cl::opt<std::string> InputFilename(cl::Positional,
     35                                           cl::desc("<input .llvm file>"),
     36                                           cl::init("-"));
     37 
     38 static cl::opt<std::string> OutputFilename("o",
     39                                            cl::desc("Override output filename"),
     40                                            cl::value_desc("filename"));
     41 
     42 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"));
     43 
     44 static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
     45                                    cl::init(false));
     46 
     47 static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
     48                                     cl::init(false));
     49 
     50 static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
     51                              cl::Hidden);
     52 
     53 static cl::opt<bool>
     54     DisableVerify("disable-verify", cl::Hidden,
     55                   cl::desc("Do not run verifier on input LLVM (dangerous!)"));
     56 
     57 static cl::opt<bool> PreserveBitcodeUseListOrder(
     58     "preserve-bc-uselistorder",
     59     cl::desc("Preserve use-list order when writing LLVM bitcode."),
     60     cl::init(true), cl::Hidden);
     61 
     62 static void WriteOutputFile(const Module *M) {
     63   // Infer the output filename if needed.
     64   if (OutputFilename.empty()) {
     65     if (InputFilename == "-") {
     66       OutputFilename = "-";
     67     } else {
     68       StringRef IFN = InputFilename;
     69       OutputFilename = (IFN.endswith(".ll") ? IFN.drop_back(3) : IFN).str();
     70       OutputFilename += ".bc";
     71     }
     72   }
     73 
     74   std::error_code EC;
     75   std::unique_ptr<tool_output_file> Out(
     76       new tool_output_file(OutputFilename, EC, sys::fs::F_None));
     77   if (EC) {
     78     errs() << EC.message() << '\n';
     79     exit(1);
     80   }
     81 
     82   if (Force || !CheckBitcodeOutputToConsole(Out->os(), true))
     83     WriteBitcodeToFile(M, Out->os(), PreserveBitcodeUseListOrder, nullptr,
     84                        EmitModuleHash);
     85 
     86   // Declare success.
     87   Out->keep();
     88 }
     89 
     90 int main(int argc, char **argv) {
     91   // Print a stack trace if we signal out.
     92   sys::PrintStackTraceOnErrorSignal(argv[0]);
     93   PrettyStackTraceProgram X(argc, argv);
     94   LLVMContext Context;
     95   llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
     96   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
     97 
     98   // Parse the file now...
     99   SMDiagnostic Err;
    100   std::unique_ptr<Module> M = parseAssemblyFile(InputFilename, Err, Context);
    101   if (!M.get()) {
    102     Err.print(argv[0], errs());
    103     return 1;
    104   }
    105 
    106   if (!DisableVerify) {
    107     std::string ErrorStr;
    108     raw_string_ostream OS(ErrorStr);
    109     if (verifyModule(*M.get(), &OS)) {
    110       errs() << argv[0]
    111              << ": assembly parsed, but does not verify as correct!\n";
    112       errs() << OS.str();
    113       return 1;
    114     }
    115   }
    116 
    117   if (DumpAsm)
    118     errs() << "Here's the assembly:\n" << *M.get();
    119 
    120   if (!DisableOutput)
    121     WriteOutputFile(M.get());
    122 
    123   return 0;
    124 }
    125