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 } 175