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