tools/llvm-as/llvm-as.cpp

   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/BitcodeWriter.h"
  20 #include "llvm/IR/LLVMContext.h"
  21 #include "llvm/IR/Module.h"
  22 #include "llvm/IR/ModuleSummaryIndex.h"
  23 #include "llvm/IR/Verifier.h"
  24 #include "llvm/Support/CommandLine.h"
  25 #include "llvm/Support/FileSystem.h"
  26 #include "llvm/Support/InitLLVM.h"
  27 #include "llvm/Support/ManagedStatic.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 cl::opt<std::string> ClDataLayout("data-layout",
  63                                          cl::desc("data layout string to use"),
  64                                          cl::value_desc("layout-string"),
  65                                          cl::init(""));
  66
  67 static void WriteOutputFile(const Module *M, const ModuleSummaryIndex *Index) {
  68   // Infer the output filename if needed.
  69   if (OutputFilename.empty()) {
  70     if (InputFilename == "-") {
  71       OutputFilename = "-";
  72     } else {
  73       StringRef IFN = InputFilename;
  74       OutputFilename = (IFN.endswith(".ll") ? IFN.drop_back(3) : IFN).str();
  75       OutputFilename += ".bc";
  76     }
  77   }
  78
  79   std::error_code EC;
  80   std::unique_ptr<ToolOutputFile> Out(
  81       new ToolOutputFile(OutputFilename, EC, sys::fs::F_None));
  82   if (EC) {
  83     errs() << EC.message() << '\n';
  84     exit(1);
  85   }
  86
  87   if (Force || !CheckBitcodeOutputToConsole(Out->os(), true)) {
  88     const ModuleSummaryIndex *IndexToWrite = nullptr;
  89     // Don't attempt to write a summary index unless it contains any entries.
  90     // Otherwise we get an empty summary section.
  91     if (Index && Index->begin() != Index->end())
  92       IndexToWrite = Index;
  93     if (!IndexToWrite || (M && (!M->empty() || !M->global_empty())))
  94       // If we have a non-empty Module, then we write the Module plus
  95       // any non-null Index along with it as a per-module Index.
  96       // If both are empty, this will give an empty module block, which is
  97       // the expected behavior.
  98       WriteBitcodeToFile(*M, Out->os(), PreserveBitcodeUseListOrder,
  99                          IndexToWrite, EmitModuleHash);
 100     else
 101       // Otherwise, with an empty Module but non-empty Index, we write a
 102       // combined index.
 103       WriteIndexToFile(*IndexToWrite, Out->os());
 104   }
 105
 106   // Declare success.
 107   Out->keep();
 108 }
 109
 110 int main(int argc, char **argv) {
 111   InitLLVM X(argc, argv);
 112   LLVMContext Context;
 113   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
 114
 115   // Parse the file now...
 116   SMDiagnostic Err;
 117   auto ModuleAndIndex = parseAssemblyFileWithIndex(
 118       InputFilename, Err, Context, nullptr, !DisableVerify, ClDataLayout);
 119   std::unique_ptr<Module> M = std::move(ModuleAndIndex.Mod);
 120   if (!M.get()) {
 121     Err.print(argv[0], errs());
 122     return 1;
 123   }
 124   std::unique_ptr<ModuleSummaryIndex> Index = std::move(ModuleAndIndex.Index);
 125
 126   if (!DisableVerify) {
 127     std::string ErrorStr;
 128     raw_string_ostream OS(ErrorStr);
 129     if (verifyModule(*M.get(), &OS)) {
 130       errs() << argv[0]
 131              << ": assembly parsed, but does not verify as correct!\n";
 132       errs() << OS.str();
 133       return 1;
 134     }
 135     // TODO: Implement and call summary index verifier.
 136   }
 137
 138   if (DumpAsm) {
 139     errs() << "Here's the assembly:\n" << *M.get();
 140     if (Index.get() && Index->begin() != Index->end())
 141       Index->print(errs());
 142   }
 143
 144   if (!DisableOutput)
 145     WriteOutputFile(M.get(), Index.get());
 146
 147   return 0;
 148 }