1//===-- llvm-lto: a simple command-line program to link modules with LTO --===// 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 program takes in a list of bitcode files, links them, performs link-time 11// optimization, and outputs an object file. 12// 13//===----------------------------------------------------------------------===// 14 15#include "llvm/ADT/StringSet.h" 16#include "llvm/Bitcode/ReaderWriter.h" 17#include "llvm/CodeGen/CommandFlags.h" 18#include "llvm/IR/DiagnosticPrinter.h" 19#include "llvm/IR/LLVMContext.h" 20#include "llvm/LTO/LTOCodeGenerator.h" 21#include "llvm/LTO/LTOModule.h" 22#include "llvm/Object/FunctionIndexObjectFile.h" 23#include "llvm/Support/CommandLine.h" 24#include "llvm/Support/FileSystem.h" 25#include "llvm/Support/ManagedStatic.h" 26#include "llvm/Support/PrettyStackTrace.h" 27#include "llvm/Support/Signals.h" 28#include "llvm/Support/TargetSelect.h" 29#include "llvm/Support/ToolOutputFile.h" 30#include "llvm/Support/raw_ostream.h" 31#include <list> 32 33using namespace llvm; 34 35static cl::opt<char> 36OptLevel("O", 37 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] " 38 "(default = '-O2')"), 39 cl::Prefix, 40 cl::ZeroOrMore, 41 cl::init('2')); 42 43static cl::opt<bool> DisableVerify( 44 "disable-verify", cl::init(false), 45 cl::desc("Do not run the verifier during the optimization pipeline")); 46 47static cl::opt<bool> 48DisableInline("disable-inlining", cl::init(false), 49 cl::desc("Do not run the inliner pass")); 50 51static cl::opt<bool> 52DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false), 53 cl::desc("Do not run the GVN load PRE pass")); 54 55static cl::opt<bool> 56DisableLTOVectorization("disable-lto-vectorization", cl::init(false), 57 cl::desc("Do not run loop or slp vectorization during LTO")); 58 59static cl::opt<bool> 60UseDiagnosticHandler("use-diagnostic-handler", cl::init(false), 61 cl::desc("Use a diagnostic handler to test the handler interface")); 62 63static cl::opt<bool> 64 ThinLTO("thinlto", cl::init(false), 65 cl::desc("Only write combined global index for ThinLTO backends")); 66 67static cl::opt<bool> 68SaveModuleFile("save-merged-module", cl::init(false), 69 cl::desc("Write merged LTO module to file before CodeGen")); 70 71static cl::list<std::string> 72InputFilenames(cl::Positional, cl::OneOrMore, 73 cl::desc("<input bitcode files>")); 74 75static cl::opt<std::string> 76OutputFilename("o", cl::init(""), 77 cl::desc("Override output filename"), 78 cl::value_desc("filename")); 79 80static cl::list<std::string> 81ExportedSymbols("exported-symbol", 82 cl::desc("Symbol to export from the resulting object file"), 83 cl::ZeroOrMore); 84 85static cl::list<std::string> 86DSOSymbols("dso-symbol", 87 cl::desc("Symbol to put in the symtab in the resulting dso"), 88 cl::ZeroOrMore); 89 90static cl::opt<bool> ListSymbolsOnly( 91 "list-symbols-only", cl::init(false), 92 cl::desc("Instead of running LTO, list the symbols in each IR file")); 93 94static cl::opt<bool> SetMergedModule( 95 "set-merged-module", cl::init(false), 96 cl::desc("Use the first input module as the merged module")); 97 98static cl::opt<unsigned> Parallelism("j", cl::Prefix, cl::init(1), 99 cl::desc("Number of backend threads")); 100 101namespace { 102struct ModuleInfo { 103 std::vector<bool> CanBeHidden; 104}; 105} 106 107static void handleDiagnostics(lto_codegen_diagnostic_severity_t Severity, 108 const char *Msg, void *) { 109 errs() << "llvm-lto: "; 110 switch (Severity) { 111 case LTO_DS_NOTE: 112 errs() << "note: "; 113 break; 114 case LTO_DS_REMARK: 115 errs() << "remark: "; 116 break; 117 case LTO_DS_ERROR: 118 errs() << "error: "; 119 break; 120 case LTO_DS_WARNING: 121 errs() << "warning: "; 122 break; 123 } 124 errs() << Msg << "\n"; 125} 126 127static std::string CurrentActivity; 128static void diagnosticHandler(const DiagnosticInfo &DI) { 129 raw_ostream &OS = errs(); 130 OS << "llvm-lto: "; 131 switch (DI.getSeverity()) { 132 case DS_Error: 133 OS << "error"; 134 break; 135 case DS_Warning: 136 OS << "warning"; 137 break; 138 case DS_Remark: 139 OS << "remark"; 140 break; 141 case DS_Note: 142 OS << "note"; 143 break; 144 } 145 if (!CurrentActivity.empty()) 146 OS << ' ' << CurrentActivity; 147 OS << ": "; 148 149 DiagnosticPrinterRawOStream DP(OS); 150 DI.print(DP); 151 OS << '\n'; 152 153 if (DI.getSeverity() == DS_Error) 154 exit(1); 155} 156 157static void diagnosticHandlerWithContenxt(const DiagnosticInfo &DI, 158 void *Context) { 159 diagnosticHandler(DI); 160} 161 162static void error(const Twine &Msg) { 163 errs() << "llvm-lto: " << Msg << '\n'; 164 exit(1); 165} 166 167static void error(std::error_code EC, const Twine &Prefix) { 168 if (EC) 169 error(Prefix + ": " + EC.message()); 170} 171 172template <typename T> 173static void error(const ErrorOr<T> &V, const Twine &Prefix) { 174 error(V.getError(), Prefix); 175} 176 177static std::unique_ptr<LTOModule> 178getLocalLTOModule(StringRef Path, std::unique_ptr<MemoryBuffer> &Buffer, 179 const TargetOptions &Options) { 180 ErrorOr<std::unique_ptr<MemoryBuffer>> BufferOrErr = 181 MemoryBuffer::getFile(Path); 182 error(BufferOrErr, "error loading file '" + Path + "'"); 183 Buffer = std::move(BufferOrErr.get()); 184 CurrentActivity = ("loading file '" + Path + "'").str(); 185 ErrorOr<std::unique_ptr<LTOModule>> Ret = LTOModule::createInLocalContext( 186 Buffer->getBufferStart(), Buffer->getBufferSize(), Options, Path); 187 CurrentActivity = ""; 188 return std::move(*Ret); 189} 190 191/// \brief List symbols in each IR file. 192/// 193/// The main point here is to provide lit-testable coverage for the LTOModule 194/// functionality that's exposed by the C API to list symbols. Moreover, this 195/// provides testing coverage for modules that have been created in their own 196/// contexts. 197static void listSymbols(const TargetOptions &Options) { 198 for (auto &Filename : InputFilenames) { 199 std::unique_ptr<MemoryBuffer> Buffer; 200 std::unique_ptr<LTOModule> Module = 201 getLocalLTOModule(Filename, Buffer, Options); 202 203 // List the symbols. 204 outs() << Filename << ":\n"; 205 for (int I = 0, E = Module->getSymbolCount(); I != E; ++I) 206 outs() << Module->getSymbolName(I) << "\n"; 207 } 208} 209 210/// Create a combined index file from the input IR files and write it. 211/// 212/// This is meant to enable testing of ThinLTO combined index generation, 213/// currently available via the gold plugin via -thinlto. 214static void createCombinedFunctionIndex() { 215 FunctionInfoIndex CombinedIndex; 216 uint64_t NextModuleId = 0; 217 for (auto &Filename : InputFilenames) { 218 CurrentActivity = "loading file '" + Filename + "'"; 219 ErrorOr<std::unique_ptr<FunctionInfoIndex>> IndexOrErr = 220 llvm::getFunctionIndexForFile(Filename, diagnosticHandler); 221 std::unique_ptr<FunctionInfoIndex> Index = std::move(IndexOrErr.get()); 222 CurrentActivity = ""; 223 // Skip files without a function summary. 224 if (!Index) 225 continue; 226 CombinedIndex.mergeFrom(std::move(Index), ++NextModuleId); 227 } 228 std::error_code EC; 229 assert(!OutputFilename.empty()); 230 raw_fd_ostream OS(OutputFilename + ".thinlto.bc", EC, 231 sys::fs::OpenFlags::F_None); 232 error(EC, "error opening the file '" + OutputFilename + ".thinlto.bc'"); 233 WriteFunctionSummaryToFile(CombinedIndex, OS); 234 OS.close(); 235} 236 237int main(int argc, char **argv) { 238 // Print a stack trace if we signal out. 239 sys::PrintStackTraceOnErrorSignal(); 240 PrettyStackTraceProgram X(argc, argv); 241 242 llvm_shutdown_obj Y; // Call llvm_shutdown() on exit. 243 cl::ParseCommandLineOptions(argc, argv, "llvm LTO linker\n"); 244 245 if (OptLevel < '0' || OptLevel > '3') 246 error("optimization level must be between 0 and 3"); 247 248 // Initialize the configured targets. 249 InitializeAllTargets(); 250 InitializeAllTargetMCs(); 251 InitializeAllAsmPrinters(); 252 InitializeAllAsmParsers(); 253 254 // set up the TargetOptions for the machine 255 TargetOptions Options = InitTargetOptionsFromCodeGenFlags(); 256 257 if (ListSymbolsOnly) { 258 listSymbols(Options); 259 return 0; 260 } 261 262 if (ThinLTO) { 263 createCombinedFunctionIndex(); 264 return 0; 265 } 266 267 unsigned BaseArg = 0; 268 269 LLVMContext Context; 270 Context.setDiagnosticHandler(diagnosticHandlerWithContenxt, nullptr, true); 271 272 LTOCodeGenerator CodeGen(Context); 273 274 if (UseDiagnosticHandler) 275 CodeGen.setDiagnosticHandler(handleDiagnostics, nullptr); 276 277 CodeGen.setCodePICModel(RelocModel); 278 279 CodeGen.setDebugInfo(LTO_DEBUG_MODEL_DWARF); 280 CodeGen.setTargetOptions(Options); 281 282 llvm::StringSet<llvm::MallocAllocator> DSOSymbolsSet; 283 for (unsigned i = 0; i < DSOSymbols.size(); ++i) 284 DSOSymbolsSet.insert(DSOSymbols[i]); 285 286 std::vector<std::string> KeptDSOSyms; 287 288 for (unsigned i = BaseArg; i < InputFilenames.size(); ++i) { 289 CurrentActivity = "loading file '" + InputFilenames[i] + "'"; 290 ErrorOr<std::unique_ptr<LTOModule>> ModuleOrErr = 291 LTOModule::createFromFile(Context, InputFilenames[i].c_str(), Options); 292 error(ModuleOrErr, "error " + CurrentActivity); 293 std::unique_ptr<LTOModule> &Module = *ModuleOrErr; 294 CurrentActivity = ""; 295 296 unsigned NumSyms = Module->getSymbolCount(); 297 for (unsigned I = 0; I < NumSyms; ++I) { 298 StringRef Name = Module->getSymbolName(I); 299 if (!DSOSymbolsSet.count(Name)) 300 continue; 301 lto_symbol_attributes Attrs = Module->getSymbolAttributes(I); 302 unsigned Scope = Attrs & LTO_SYMBOL_SCOPE_MASK; 303 if (Scope != LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN) 304 KeptDSOSyms.push_back(Name); 305 } 306 307 // We use the first input module as the destination module when 308 // SetMergedModule is true. 309 if (SetMergedModule && i == BaseArg) { 310 // Transfer ownership to the code generator. 311 CodeGen.setModule(std::move(Module)); 312 } else if (!CodeGen.addModule(Module.get())) { 313 // Print a message here so that we know addModule() did not abort. 314 errs() << argv[0] << ": error adding file '" << InputFilenames[i] << "'\n"; 315 return 1; 316 } 317 } 318 319 // Add all the exported symbols to the table of symbols to preserve. 320 for (unsigned i = 0; i < ExportedSymbols.size(); ++i) 321 CodeGen.addMustPreserveSymbol(ExportedSymbols[i].c_str()); 322 323 // Add all the dso symbols to the table of symbols to expose. 324 for (unsigned i = 0; i < KeptDSOSyms.size(); ++i) 325 CodeGen.addMustPreserveSymbol(KeptDSOSyms[i].c_str()); 326 327 // Set cpu and attrs strings for the default target/subtarget. 328 CodeGen.setCpu(MCPU.c_str()); 329 330 CodeGen.setOptLevel(OptLevel - '0'); 331 332 std::string attrs; 333 for (unsigned i = 0; i < MAttrs.size(); ++i) { 334 if (i > 0) 335 attrs.append(","); 336 attrs.append(MAttrs[i]); 337 } 338 339 if (!attrs.empty()) 340 CodeGen.setAttr(attrs.c_str()); 341 342 if (FileType.getNumOccurrences()) 343 CodeGen.setFileType(FileType); 344 345 if (!OutputFilename.empty()) { 346 if (!CodeGen.optimize(DisableVerify, DisableInline, DisableGVNLoadPRE, 347 DisableLTOVectorization)) { 348 // Diagnostic messages should have been printed by the handler. 349 errs() << argv[0] << ": error optimizing the code\n"; 350 return 1; 351 } 352 353 if (SaveModuleFile) { 354 std::string ModuleFilename = OutputFilename; 355 ModuleFilename += ".merged.bc"; 356 std::string ErrMsg; 357 358 if (!CodeGen.writeMergedModules(ModuleFilename.c_str())) { 359 errs() << argv[0] << ": writing merged module failed.\n"; 360 return 1; 361 } 362 } 363 364 std::list<tool_output_file> OSs; 365 std::vector<raw_pwrite_stream *> OSPtrs; 366 for (unsigned I = 0; I != Parallelism; ++I) { 367 std::string PartFilename = OutputFilename; 368 if (Parallelism != 1) 369 PartFilename += "." + utostr(I); 370 std::error_code EC; 371 OSs.emplace_back(PartFilename, EC, sys::fs::F_None); 372 if (EC) { 373 errs() << argv[0] << ": error opening the file '" << PartFilename 374 << "': " << EC.message() << "\n"; 375 return 1; 376 } 377 OSPtrs.push_back(&OSs.back().os()); 378 } 379 380 if (!CodeGen.compileOptimized(OSPtrs)) { 381 // Diagnostic messages should have been printed by the handler. 382 errs() << argv[0] << ": error compiling the code\n"; 383 return 1; 384 } 385 386 for (tool_output_file &OS : OSs) 387 OS.keep(); 388 } else { 389 if (Parallelism != 1) { 390 errs() << argv[0] << ": -j must be specified together with -o\n"; 391 return 1; 392 } 393 394 if (SaveModuleFile) { 395 errs() << argv[0] << ": -save-merged-module must be specified with -o\n"; 396 return 1; 397 } 398 399 const char *OutputName = nullptr; 400 if (!CodeGen.compile_to_file(&OutputName, DisableVerify, DisableInline, 401 DisableGVNLoadPRE, DisableLTOVectorization)) { 402 // Diagnostic messages should have been printed by the handler. 403 errs() << argv[0] << ": error compiling the code\n"; 404 return 1; 405 } 406 407 outs() << "Wrote native object file '" << OutputName << "'\n"; 408 } 409 410 return 0; 411} 412