llvm/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/SourceMgr.h"
  27 #include "llvm/Support/SystemUtils.h"
  28 #include "llvm/Support/ToolOutputFile.h"
  29 #include <memory>
  30 #include <optional>
  31 using namespace llvm;
  32
  33 cl::OptionCategory AsCat("llvm-as Options");
  34
  35 static cl::opt<std::string>
  36     InputFilename(cl::Positional, cl::desc("<input .ll file>"), cl::init("-"));
  37
  38 static cl::opt<std::string> OutputFilename("o",
  39                                            cl::desc("Override output filename"),
  40                                            cl::value_desc("filename"),
  41                                            cl::cat(AsCat));
  42
  43 static cl::opt<bool> Force("f", cl::desc("Enable binary output on terminals"),
  44                            cl::cat(AsCat));
  45
  46 static cl::opt<bool> DisableOutput("disable-output", cl::desc("Disable output"),
  47                                    cl::init(false), cl::cat(AsCat));
  48
  49 static cl::opt<bool> EmitModuleHash("module-hash", cl::desc("Emit module hash"),
  50                                     cl::init(false), cl::cat(AsCat));
  51
  52 static cl::opt<bool> DumpAsm("d", cl::desc("Print assembly as parsed"),
  53                              cl::Hidden, cl::cat(AsCat));
  54
  55 static cl::opt<bool>
  56     DisableVerify("disable-verify", cl::Hidden,
  57                   cl::desc("Do not run verifier on input LLVM (dangerous!)"),
  58                   cl::cat(AsCat));
  59
  60 static cl::opt<bool> PreserveBitcodeUseListOrder(
  61     "preserve-bc-uselistorder",
  62     cl::desc("Preserve use-list order when writing LLVM bitcode."),
  63     cl::init(true), cl::Hidden, cl::cat(AsCat));
  64
  65 static cl::opt<std::string> ClDataLayout("data-layout",
  66                                          cl::desc("data layout string to use"),
  67                                          cl::value_desc("layout-string"),
  68                                          cl::init(""), cl::cat(AsCat));
  69 extern cl::opt<bool> UseNewDbgInfoFormat;
  70 extern bool WriteNewDbgInfoFormatToBitcode;
  71
  72 static void WriteOutputFile(const Module *M, const ModuleSummaryIndex *Index) {
  73   // Infer the output filename if needed.
  74   if (OutputFilename.empty()) {
  75     if (InputFilename == "-") {
  76       OutputFilename = "-";
  77     } else {
  78       StringRef IFN = InputFilename;
  79       OutputFilename = (IFN.ends_with(".ll") ? IFN.drop_back(3) : IFN).str();
  80       OutputFilename += ".bc";
  81     }
  82   }
  83
  84   std::error_code EC;
  85   std::unique_ptr<ToolOutputFile> Out(
  86       new ToolOutputFile(OutputFilename, EC, sys::fs::OF_None));
  87   if (EC) {
  88     errs() << EC.message() << '\n';
  89     exit(1);
  90   }
  91
  92   if (Force || !CheckBitcodeOutputToConsole(Out->os())) {
  93     const ModuleSummaryIndex *IndexToWrite = nullptr;
  94     // Don't attempt to write a summary index unless it contains any entries or
  95     // has non-zero flags. The latter is used to assemble dummy index files for
  96     // skipping modules by distributed ThinLTO backends. Otherwise we get an empty
  97     // summary section.
  98     if (Index && (Index->begin() != Index->end() || Index->getFlags()))
  99       IndexToWrite = Index;
 100     if (!IndexToWrite || (M && (!M->empty() || !M->global_empty())))
 101       // If we have a non-empty Module, then we write the Module plus
 102       // any non-null Index along with it as a per-module Index.
 103       // If both are empty, this will give an empty module block, which is
 104       // the expected behavior.
 105       WriteBitcodeToFile(*M, Out->os(), PreserveBitcodeUseListOrder,
 106                          IndexToWrite, EmitModuleHash);
 107     else
 108       // Otherwise, with an empty Module but non-empty Index, we write a
 109       // combined index.
 110       writeIndexToFile(*IndexToWrite, Out->os());
 111   }
 112
 113   // Declare success.
 114   Out->keep();
 115 }
 116
 117 int main(int argc, char **argv) {
 118   InitLLVM X(argc, argv);
 119   cl::HideUnrelatedOptions(AsCat);
 120   cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
 121   LLVMContext Context;
 122
 123   // Parse the file now...
 124   SMDiagnostic Err;
 125   auto SetDataLayout = [](StringRef, StringRef) -> std::optional<std::string> {
 126     if (ClDataLayout.empty())
 127       return std::nullopt;
 128     return ClDataLayout;
 129   };
 130   ParsedModuleAndIndex ModuleAndIndex;
 131   if (DisableVerify) {
 132     ModuleAndIndex = parseAssemblyFileWithIndexNoUpgradeDebugInfo(
 133         InputFilename, Err, Context, nullptr, SetDataLayout);
 134   } else {
 135     ModuleAndIndex = parseAssemblyFileWithIndex(InputFilename, Err, Context,
 136                                                 nullptr, SetDataLayout);
 137   }
 138   std::unique_ptr<Module> M = std::move(ModuleAndIndex.Mod);
 139   if (!M) {
 140     Err.print(argv[0], errs());
 141     return 1;
 142   }
 143
 144   // Convert to new debug format if requested.
 145   M->setIsNewDbgInfoFormat(UseNewDbgInfoFormat &&
 146                            WriteNewDbgInfoFormatToBitcode);
 147   if (M->IsNewDbgInfoFormat)
 148     M->removeDebugIntrinsicDeclarations();
 149
 150   std::unique_ptr<ModuleSummaryIndex> Index = std::move(ModuleAndIndex.Index);
 151
 152   if (!DisableVerify) {
 153     std::string ErrorStr;
 154     raw_string_ostream OS(ErrorStr);
 155     if (verifyModule(*M, &OS)) {
 156       errs() << argv[0]
 157              << ": assembly parsed, but does not verify as correct!\n";
 158       errs() << OS.str();
 159       return 1;
 160     }
 161     // TODO: Implement and call summary index verifier.
 162   }
 163
 164   if (DumpAsm) {
 165     errs() << "Here's the assembly:\n" << *M;
 166     if (Index.get() && Index->begin() != Index->end())
 167       Index->print(errs());
 168   }
 169
 170   if (!DisableOutput)
 171     WriteOutputFile(M.get(), Index.get());
 172
 173   return 0;
 174 }