tools/llvm-as/llvm-as.cpp

   1 //===--- llvm-as.cpp - The low-level LLVM assembler -----------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 //  This utility may be invoked in the following manner:
  10 //   llvm-as --help         - Output information about command line switches
  11 //   llvm-as [options]      - Read LLVM asm from stdin, write bitcode to stdout
  12 //   llvm-as [options] x.ll - Read LLVM asm from the x.ll file, write bitcode
  13 //                            to the x.bc file.
  14 //
  15 //===----------------------------------------------------------------------===//
  16
  17 #include "llvm/AsmParser/Parser.h"
  18 #include "llvm/Bitcode/BitcodeWriter.h"
  19 #include "llvm/IR/LLVMContext.h"
  20 #include "llvm/IR/Module.h"
  21 #include "llvm/IR/ModuleSummaryIndex.h"
  22 #include "llvm/IR/Verifier.h"
  23 #include "llvm/Support/CommandLine.h"
  24 #include "llvm/Support/FileSystem.h"
  25 #include "llvm/Support/InitLLVM.h"
  26 #include "llvm/Support/ManagedStatic.h"
  27 #include "llvm/Support/SourceMgr.h"
  28 #include "llvm/Support/SystemUtils.h"
  29 #include "llvm/Support/ToolOutputFile.h"
  30 #include <memory>
  31 using namespace llvm;
  32
  33 static cl::opt<std::string> InputFilename(cl::Positional,
  34                                           cl::desc("<input .llvm file>"),
  35                                           cl::init("-"));
  36
  37 static cl::opt<std::string> OutputFilename("o",
  38                                            cl::desc("Override output filename"),
  39                                            cl::value_desc("filename"));
  40
  41 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"));
  42
  43 static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
  44                                    cl::init(false));
  45
  46 static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
  47                                     cl::init(false));
  48
  49 static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
  50                              cl::Hidden);
  51
  52 static cl::opt<bool>
  53     DisableVerify("disable-verify", cl::Hidden,
  54                   cl::desc("Do not run verifier on input LLVM (dangerous!)"));
  55
  56 static cl::opt<bool> PreserveBitcodeUseListOrder(
  57     "preserve-bc-uselistorder",
  58     cl::desc("Preserve use-list order when writing LLVM bitcode."),
  59     cl::init(true), cl::Hidden);
  60
  61 static cl::opt<std::string> ClDataLayout("data-layout",
  62                                          cl::desc("data layout string to use"),
  63                                          cl::value_desc("layout-string"),
  64                                          cl::init(""));
  65
  66 static void WriteOutputFile(const Module *M, const ModuleSummaryIndex *Index) {
  67   // Infer the output filename if needed.
  68   if (OutputFilename.empty()) {
  69     if (InputFilename == "-") {
  70       OutputFilename = "-";
  71     } else {
  72       StringRef IFN = InputFilename;
  73       OutputFilename = (IFN.endswith(".ll") ? IFN.drop_back(3) : IFN).str();
  74       OutputFilename += ".bc";
  75     }
  76   }
  77
  78   std::error_code EC;
  79   std::unique_ptr<ToolOutputFile> Out(
  80       new ToolOutputFile(OutputFilename, EC, sys::fs::F_None));
  81   if (EC) {
  82     errs() << EC.message() << '\n';
  83     exit(1);
  84   }
  85
  86   if (Force || !CheckBitcodeOutputToConsole(Out->os(), true)) {
  87     const ModuleSummaryIndex *IndexToWrite = nullptr;
  88     // Don't attempt to write a summary index unless it contains any entries.
  89     // Otherwise we get an empty summary section.
  90     if (Index && Index->begin() != Index->end())
  91       IndexToWrite = Index;
  92     if (!IndexToWrite || (M && (!M->empty() || !M->global_empty())))
  93       // If we have a non-empty Module, then we write the Module plus
  94       // any non-null Index along with it as a per-module Index.
  95       // If both are empty, this will give an empty module block, which is
  96       // the expected behavior.
  97       WriteBitcodeToFile(*M, Out->os(), PreserveBitcodeUseListOrder,
  98                          IndexToWrite, EmitModuleHash);
  99     else
 100       // Otherwise, with an empty Module but non-empty Index, we write a
 101       // combined index.
 102       WriteIndexToFile(*IndexToWrite, Out->os());
 103   }
 104
 105   // Declare success.
 106   Out->keep();
 107 }
 108
 109 int main(int argc, char **argv) {
 110   InitLLVM X(argc, argv);
 111   LLVMContext Context;
 112   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
 113
 114   // Parse the file now...
 115   SMDiagnostic Err;
 116   auto ModuleAndIndex = parseAssemblyFileWithIndex(
 117       InputFilename, Err, Context, nullptr, !DisableVerify, ClDataLayout);
 118   std::unique_ptr<Module> M = std::move(ModuleAndIndex.Mod);
 119   if (!M.get()) {
 120     Err.print(argv[0], errs());
 121     return 1;
 122   }
 123   std::unique_ptr<ModuleSummaryIndex> Index = std::move(ModuleAndIndex.Index);
 124
 125   if (!DisableVerify) {
 126     std::string ErrorStr;
 127     raw_string_ostream OS(ErrorStr);
 128     if (verifyModule(*M.get(), &OS)) {
 129       errs() << argv[0]
 130              << ": assembly parsed, but does not verify as correct!\n";
 131       errs() << OS.str();
 132       return 1;
 133     }
 134     // TODO: Implement and call summary index verifier.
 135   }
 136
 137   if (DumpAsm) {
 138     errs() << "Here's the assembly:\n" << *M.get();
 139     if (Index.get() && Index->begin() != Index->end())
 140       Index->print(errs());
 141   }
 142
 143   if (!DisableOutput)
 144     WriteOutputFile(M.get(), Index.get());
 145
 146   return 0;
 147 }