1 //===-- llvm-lto2: test harness for the resolution-based LTO interface ----===// 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 program takes in a list of bitcode files, links them and performs 10 // link-time optimization according to the provided symbol resolutions using the 11 // resolution-based LTO interface, and outputs one or more object files. 12 // 13 // This program is intended to eventually replace llvm-lto which uses the legacy 14 // LTO interface. 15 // 16 //===----------------------------------------------------------------------===// 17 18 #include "llvm/Bitcode/BitcodeReader.h" 19 #include "llvm/CodeGen/CommandFlags.h" 20 #include "llvm/Config/llvm-config.h" 21 #include "llvm/IR/DiagnosticPrinter.h" 22 #include "llvm/LTO/LTO.h" 23 #include "llvm/Passes/PassPlugin.h" 24 #include "llvm/Remarks/HotnessThresholdParser.h" 25 #include "llvm/Support/Caching.h" 26 #include "llvm/Support/CommandLine.h" 27 #include "llvm/Support/FileSystem.h" 28 #include "llvm/Support/InitLLVM.h" 29 #include "llvm/Support/PluginLoader.h" 30 #include "llvm/Support/TargetSelect.h" 31 #include "llvm/Support/Threading.h" 32 #include <atomic> 33 34 using namespace llvm; 35 using namespace lto; 36 37 static codegen::RegisterCodeGenFlags CGF; 38 39 static cl::opt<char> 40 OptLevel("O", 41 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] " 42 "(default = '-O2')"), 43 cl::Prefix, cl::init('2')); 44 45 static cl::opt<char> CGOptLevel( 46 "cg-opt-level", 47 cl::desc("Codegen optimization level (0, 1, 2 or 3, default = '2')"), 48 cl::init('2')); 49 50 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore, 51 cl::desc("<input bitcode files>")); 52 53 static cl::opt<std::string> OutputFilename("o", cl::Required, 54 cl::desc("Output filename"), 55 cl::value_desc("filename")); 56 57 static cl::opt<std::string> CacheDir("cache-dir", cl::desc("Cache Directory"), 58 cl::value_desc("directory")); 59 60 static cl::opt<std::string> OptPipeline("opt-pipeline", 61 cl::desc("Optimizer Pipeline"), 62 cl::value_desc("pipeline")); 63 64 static cl::opt<std::string> AAPipeline("aa-pipeline", 65 cl::desc("Alias Analysis Pipeline"), 66 cl::value_desc("aapipeline")); 67 68 static cl::opt<bool> SaveTemps("save-temps", cl::desc("Save temporary files")); 69 70 static cl::list<std::string> SelectSaveTemps( 71 "select-save-temps", 72 cl::value_desc("One, or multiple of: " 73 "resolution,preopt,promote,internalize,import,opt,precodegen" 74 ",combinedindex"), 75 cl::desc("Save selected temporary files. Cannot be specified together with " 76 "-save-temps"), 77 cl::CommaSeparated); 78 79 constexpr const char *SaveTempsValues[] = { 80 "resolution", "preopt", "promote", "internalize", 81 "import", "opt", "precodegen", "combinedindex"}; 82 83 static cl::opt<bool> 84 ThinLTODistributedIndexes("thinlto-distributed-indexes", 85 cl::desc("Write out individual index and " 86 "import files for the " 87 "distributed backend case")); 88 89 static cl::opt<bool> 90 ThinLTOEmitIndexes("thinlto-emit-indexes", 91 cl::desc("Write out individual index files via " 92 "InProcessThinLTO")); 93 94 static cl::opt<bool> 95 ThinLTOEmitImports("thinlto-emit-imports", 96 cl::desc("Write out individual imports files via " 97 "InProcessThinLTO. Has no effect unless " 98 "specified with -thinlto-emit-indexes or " 99 "-thinlto-distributed-indexes")); 100 101 // Default to using all available threads in the system, but using only one 102 // thread per core (no SMT). 103 // Use -thinlto-threads=all to use hardware_concurrency() instead, which means 104 // to use all hardware threads or cores in the system. 105 static cl::opt<std::string> Threads("thinlto-threads"); 106 107 static cl::list<std::string> SymbolResolutions( 108 "r", 109 cl::desc("Specify a symbol resolution: filename,symbolname,resolution\n" 110 "where \"resolution\" is a sequence (which may be empty) of the\n" 111 "following characters:\n" 112 " p - prevailing: the linker has chosen this definition of the\n" 113 " symbol\n" 114 " l - local: the definition of this symbol is unpreemptable at\n" 115 " runtime and is known to be in this linkage unit\n" 116 " x - externally visible: the definition of this symbol is\n" 117 " visible outside of the LTO unit\n" 118 "A resolution for each symbol must be specified")); 119 120 static cl::opt<std::string> OverrideTriple( 121 "override-triple", 122 cl::desc("Replace target triples in input files with this triple")); 123 124 static cl::opt<std::string> DefaultTriple( 125 "default-triple", 126 cl::desc( 127 "Replace unspecified target triples in input files with this triple")); 128 129 static cl::opt<bool> RemarksWithHotness( 130 "pass-remarks-with-hotness", 131 cl::desc("With PGO, include profile count in optimization remarks"), 132 cl::Hidden); 133 134 cl::opt<Optional<uint64_t>, false, remarks::HotnessThresholdParser> 135 RemarksHotnessThreshold( 136 "pass-remarks-hotness-threshold", 137 cl::desc("Minimum profile count required for an " 138 "optimization remark to be output." 139 " Use 'auto' to apply the threshold from profile summary."), 140 cl::value_desc("uint or 'auto'"), cl::init(0), cl::Hidden); 141 142 static cl::opt<std::string> 143 RemarksFilename("pass-remarks-output", 144 cl::desc("Output filename for pass remarks"), 145 cl::value_desc("filename")); 146 147 static cl::opt<std::string> 148 RemarksPasses("pass-remarks-filter", 149 cl::desc("Only record optimization remarks from passes whose " 150 "names match the given regular expression"), 151 cl::value_desc("regex")); 152 153 static cl::opt<std::string> RemarksFormat( 154 "pass-remarks-format", 155 cl::desc("The format used for serializing remarks (default: YAML)"), 156 cl::value_desc("format"), cl::init("yaml")); 157 158 static cl::opt<std::string> 159 SamplePGOFile("lto-sample-profile-file", 160 cl::desc("Specify a SamplePGO profile file")); 161 162 static cl::opt<std::string> 163 CSPGOFile("lto-cspgo-profile-file", 164 cl::desc("Specify a context sensitive PGO profile file")); 165 166 static cl::opt<bool> 167 RunCSIRInstr("lto-cspgo-gen", 168 cl::desc("Run PGO context sensitive IR instrumentation"), 169 cl::Hidden); 170 171 static cl::opt<bool> LtoOpaquePointers("lto-opaque-pointers", 172 cl::desc("Enable opaque pointer types"), 173 cl::init(true), cl::Hidden); 174 175 static cl::opt<bool> 176 DebugPassManager("debug-pass-manager", cl::Hidden, 177 cl::desc("Print pass management debugging information")); 178 179 static cl::opt<std::string> 180 StatsFile("stats-file", cl::desc("Filename to write statistics to")); 181 182 static cl::list<std::string> 183 PassPlugins("load-pass-plugin", 184 cl::desc("Load passes from plugin library")); 185 186 static cl::opt<bool> EnableFreestanding( 187 "lto-freestanding", 188 cl::desc("Enable Freestanding (disable builtins / TLI) during LTO"), 189 cl::Hidden); 190 191 static void check(Error E, std::string Msg) { 192 if (!E) 193 return; 194 handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) { 195 errs() << "llvm-lto2: " << Msg << ": " << EIB.message().c_str() << '\n'; 196 }); 197 exit(1); 198 } 199 200 template <typename T> static T check(Expected<T> E, std::string Msg) { 201 if (E) 202 return std::move(*E); 203 check(E.takeError(), Msg); 204 return T(); 205 } 206 207 static void check(std::error_code EC, std::string Msg) { 208 check(errorCodeToError(EC), Msg); 209 } 210 211 template <typename T> static T check(ErrorOr<T> E, std::string Msg) { 212 if (E) 213 return std::move(*E); 214 check(E.getError(), Msg); 215 return T(); 216 } 217 218 static int usage() { 219 errs() << "Available subcommands: dump-symtab run\n"; 220 return 1; 221 } 222 223 static int run(int argc, char **argv) { 224 cl::ParseCommandLineOptions(argc, argv, "Resolution-based LTO test harness"); 225 226 // FIXME: Workaround PR30396 which means that a symbol can appear 227 // more than once if it is defined in module-level assembly and 228 // has a GV declaration. We allow (file, symbol) pairs to have multiple 229 // resolutions and apply them in the order observed. 230 std::map<std::pair<std::string, std::string>, std::list<SymbolResolution>> 231 CommandLineResolutions; 232 for (std::string R : SymbolResolutions) { 233 StringRef Rest = R; 234 StringRef FileName, SymbolName; 235 std::tie(FileName, Rest) = Rest.split(','); 236 if (Rest.empty()) { 237 llvm::errs() << "invalid resolution: " << R << '\n'; 238 return 1; 239 } 240 std::tie(SymbolName, Rest) = Rest.split(','); 241 SymbolResolution Res; 242 for (char C : Rest) { 243 if (C == 'p') 244 Res.Prevailing = true; 245 else if (C == 'l') 246 Res.FinalDefinitionInLinkageUnit = true; 247 else if (C == 'x') 248 Res.VisibleToRegularObj = true; 249 else if (C == 'r') 250 Res.LinkerRedefined = true; 251 else { 252 llvm::errs() << "invalid character " << C << " in resolution: " << R 253 << '\n'; 254 return 1; 255 } 256 } 257 CommandLineResolutions[{std::string(FileName), std::string(SymbolName)}] 258 .push_back(Res); 259 } 260 261 std::vector<std::unique_ptr<MemoryBuffer>> MBs; 262 263 Config Conf; 264 265 Conf.CPU = codegen::getMCPU(); 266 Conf.Options = codegen::InitTargetOptionsFromCodeGenFlags(Triple()); 267 Conf.MAttrs = codegen::getMAttrs(); 268 if (auto RM = codegen::getExplicitRelocModel()) 269 Conf.RelocModel = *RM; 270 Conf.CodeModel = codegen::getExplicitCodeModel(); 271 272 Conf.DebugPassManager = DebugPassManager; 273 274 if (SaveTemps && !SelectSaveTemps.empty()) { 275 llvm::errs() << "-save-temps cannot be specified with -select-save-temps\n"; 276 return 1; 277 } 278 if (SaveTemps || !SelectSaveTemps.empty()) { 279 DenseSet<StringRef> SaveTempsArgs; 280 for (auto &S : SelectSaveTemps) 281 if (is_contained(SaveTempsValues, S)) 282 SaveTempsArgs.insert(S); 283 else { 284 llvm::errs() << ("invalid -select-save-temps argument: " + S) << '\n'; 285 return 1; 286 } 287 check(Conf.addSaveTemps(OutputFilename + ".", false, SaveTempsArgs), 288 "Config::addSaveTemps failed"); 289 } 290 291 // Optimization remarks. 292 Conf.RemarksFilename = RemarksFilename; 293 Conf.RemarksPasses = RemarksPasses; 294 Conf.RemarksWithHotness = RemarksWithHotness; 295 Conf.RemarksHotnessThreshold = RemarksHotnessThreshold; 296 Conf.RemarksFormat = RemarksFormat; 297 298 Conf.SampleProfile = SamplePGOFile; 299 Conf.CSIRProfile = CSPGOFile; 300 Conf.RunCSIRInstr = RunCSIRInstr; 301 302 // Run a custom pipeline, if asked for. 303 Conf.OptPipeline = OptPipeline; 304 Conf.AAPipeline = AAPipeline; 305 306 Conf.OptLevel = OptLevel - '0'; 307 Conf.Freestanding = EnableFreestanding; 308 for (auto &PluginFN : PassPlugins) 309 Conf.PassPlugins.push_back(PluginFN); 310 switch (CGOptLevel) { 311 case '0': 312 Conf.CGOptLevel = CodeGenOpt::None; 313 break; 314 case '1': 315 Conf.CGOptLevel = CodeGenOpt::Less; 316 break; 317 case '2': 318 Conf.CGOptLevel = CodeGenOpt::Default; 319 break; 320 case '3': 321 Conf.CGOptLevel = CodeGenOpt::Aggressive; 322 break; 323 default: 324 llvm::errs() << "invalid cg optimization level: " << CGOptLevel << '\n'; 325 return 1; 326 } 327 328 if (auto FT = codegen::getExplicitFileType()) 329 Conf.CGFileType = *FT; 330 331 Conf.OverrideTriple = OverrideTriple; 332 Conf.DefaultTriple = DefaultTriple; 333 Conf.StatsFile = StatsFile; 334 Conf.PTO.LoopVectorization = Conf.OptLevel > 1; 335 Conf.PTO.SLPVectorization = Conf.OptLevel > 1; 336 Conf.OpaquePointers = LtoOpaquePointers; 337 338 ThinBackend Backend; 339 if (ThinLTODistributedIndexes) 340 Backend = 341 createWriteIndexesThinBackend(/* OldPrefix */ "", 342 /* NewPrefix */ "", ThinLTOEmitImports, 343 /* LinkedObjectsFile */ nullptr, 344 /* OnWrite */ {}); 345 else 346 Backend = createInProcessThinBackend( 347 llvm::heavyweight_hardware_concurrency(Threads), 348 /* OnWrite */ {}, ThinLTOEmitIndexes, ThinLTOEmitImports); 349 350 // Track whether we hit an error; in particular, in the multi-threaded case, 351 // we can't exit() early because the rest of the threads wouldn't have had a 352 // change to be join-ed, and that would result in a "terminate called without 353 // an active exception". Altogether, this results in nondeterministic 354 // behavior. Instead, we don't exit in the multi-threaded case, but we make 355 // sure to report the error and then at the end (after joining cleanly) 356 // exit(1). 357 std::atomic<bool> HasErrors; 358 std::atomic_init(&HasErrors, false); 359 Conf.DiagHandler = [&](const DiagnosticInfo &DI) { 360 DiagnosticPrinterRawOStream DP(errs()); 361 DI.print(DP); 362 errs() << '\n'; 363 if (DI.getSeverity() == DS_Error) 364 HasErrors = true; 365 }; 366 367 LTO Lto(std::move(Conf), std::move(Backend)); 368 369 for (std::string F : InputFilenames) { 370 std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F); 371 std::unique_ptr<InputFile> Input = 372 check(InputFile::create(MB->getMemBufferRef()), F); 373 374 std::vector<SymbolResolution> Res; 375 for (const InputFile::Symbol &Sym : Input->symbols()) { 376 auto I = CommandLineResolutions.find({F, std::string(Sym.getName())}); 377 // If it isn't found, look for ".", which would have been added 378 // (followed by a hash) when the symbol was promoted during module 379 // splitting if it was defined in one part and used in the other. 380 // Try looking up the symbol name before the suffix. 381 if (I == CommandLineResolutions.end()) { 382 auto SplitName = Sym.getName().rsplit("."); 383 I = CommandLineResolutions.find({F, std::string(SplitName.first)}); 384 } 385 if (I == CommandLineResolutions.end()) { 386 llvm::errs() << argv[0] << ": missing symbol resolution for " << F 387 << ',' << Sym.getName() << '\n'; 388 HasErrors = true; 389 } else { 390 Res.push_back(I->second.front()); 391 I->second.pop_front(); 392 if (I->second.empty()) 393 CommandLineResolutions.erase(I); 394 } 395 } 396 397 if (HasErrors) 398 continue; 399 400 MBs.push_back(std::move(MB)); 401 check(Lto.add(std::move(Input), Res), F); 402 } 403 404 if (!CommandLineResolutions.empty()) { 405 HasErrors = true; 406 for (auto UnusedRes : CommandLineResolutions) 407 llvm::errs() << argv[0] << ": unused symbol resolution for " 408 << UnusedRes.first.first << ',' << UnusedRes.first.second 409 << '\n'; 410 } 411 if (HasErrors) 412 return 1; 413 414 auto AddStream = [&](size_t Task) -> std::unique_ptr<CachedFileStream> { 415 std::string Path = OutputFilename + "." + utostr(Task); 416 417 std::error_code EC; 418 auto S = std::make_unique<raw_fd_ostream>(Path, EC, sys::fs::OF_None); 419 check(EC, Path); 420 return std::make_unique<CachedFileStream>(std::move(S), Path); 421 }; 422 423 auto AddBuffer = [&](size_t Task, std::unique_ptr<MemoryBuffer> MB) { 424 *AddStream(Task)->OS << MB->getBuffer(); 425 }; 426 427 FileCache Cache; 428 if (!CacheDir.empty()) 429 Cache = check(localCache("ThinLTO", "Thin", CacheDir, AddBuffer), 430 "failed to create cache"); 431 432 check(Lto.run(AddStream, Cache), "LTO::run failed"); 433 return static_cast<int>(HasErrors); 434 } 435 436 static int dumpSymtab(int argc, char **argv) { 437 for (StringRef F : make_range(argv + 1, argv + argc)) { 438 std::unique_ptr<MemoryBuffer> MB = 439 check(MemoryBuffer::getFile(F), std::string(F)); 440 BitcodeFileContents BFC = 441 check(getBitcodeFileContents(*MB), std::string(F)); 442 443 if (BFC.Symtab.size() >= sizeof(irsymtab::storage::Header)) { 444 auto *Hdr = reinterpret_cast<const irsymtab::storage::Header *>( 445 BFC.Symtab.data()); 446 outs() << "version: " << Hdr->Version << '\n'; 447 if (Hdr->Version == irsymtab::storage::Header::kCurrentVersion) 448 outs() << "producer: " << Hdr->Producer.get(BFC.StrtabForSymtab) 449 << '\n'; 450 } 451 452 std::unique_ptr<InputFile> Input = 453 check(InputFile::create(MB->getMemBufferRef()), std::string(F)); 454 455 outs() << "target triple: " << Input->getTargetTriple() << '\n'; 456 Triple TT(Input->getTargetTriple()); 457 458 outs() << "source filename: " << Input->getSourceFileName() << '\n'; 459 460 if (TT.isOSBinFormatCOFF()) 461 outs() << "linker opts: " << Input->getCOFFLinkerOpts() << '\n'; 462 463 if (TT.isOSBinFormatELF()) { 464 outs() << "dependent libraries:"; 465 for (auto L : Input->getDependentLibraries()) 466 outs() << " \"" << L << "\""; 467 outs() << '\n'; 468 } 469 470 ArrayRef<std::pair<StringRef, Comdat::SelectionKind>> ComdatTable = 471 Input->getComdatTable(); 472 for (const InputFile::Symbol &Sym : Input->symbols()) { 473 switch (Sym.getVisibility()) { 474 case GlobalValue::HiddenVisibility: 475 outs() << 'H'; 476 break; 477 case GlobalValue::ProtectedVisibility: 478 outs() << 'P'; 479 break; 480 case GlobalValue::DefaultVisibility: 481 outs() << 'D'; 482 break; 483 } 484 485 auto PrintBool = [&](char C, bool B) { outs() << (B ? C : '-'); }; 486 PrintBool('U', Sym.isUndefined()); 487 PrintBool('C', Sym.isCommon()); 488 PrintBool('W', Sym.isWeak()); 489 PrintBool('I', Sym.isIndirect()); 490 PrintBool('O', Sym.canBeOmittedFromSymbolTable()); 491 PrintBool('T', Sym.isTLS()); 492 PrintBool('X', Sym.isExecutable()); 493 outs() << ' ' << Sym.getName() << '\n'; 494 495 if (Sym.isCommon()) 496 outs() << " size " << Sym.getCommonSize() << " align " 497 << Sym.getCommonAlignment() << '\n'; 498 499 int Comdat = Sym.getComdatIndex(); 500 if (Comdat != -1) { 501 outs() << " comdat "; 502 switch (ComdatTable[Comdat].second) { 503 case Comdat::Any: 504 outs() << "any"; 505 break; 506 case Comdat::ExactMatch: 507 outs() << "exactmatch"; 508 break; 509 case Comdat::Largest: 510 outs() << "largest"; 511 break; 512 case Comdat::NoDeduplicate: 513 outs() << "nodeduplicate"; 514 break; 515 case Comdat::SameSize: 516 outs() << "samesize"; 517 break; 518 } 519 outs() << ' ' << ComdatTable[Comdat].first << '\n'; 520 } 521 522 if (TT.isOSBinFormatCOFF() && Sym.isWeak() && Sym.isIndirect()) 523 outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n'; 524 525 if (!Sym.getSectionName().empty()) 526 outs() << " section " << Sym.getSectionName() << "\n"; 527 } 528 529 outs() << '\n'; 530 } 531 532 return 0; 533 } 534 535 int main(int argc, char **argv) { 536 InitLLVM X(argc, argv); 537 InitializeAllTargets(); 538 InitializeAllTargetMCs(); 539 InitializeAllAsmPrinters(); 540 InitializeAllAsmParsers(); 541 542 // FIXME: This should use llvm::cl subcommands, but it isn't currently 543 // possible to pass an argument not associated with a subcommand to a 544 // subcommand (e.g. -use-new-pm). 545 if (argc < 2) 546 return usage(); 547 548 StringRef Subcommand = argv[1]; 549 // Ensure that argv[0] is correct after adjusting argv/argc. 550 argv[1] = argv[0]; 551 if (Subcommand == "dump-symtab") 552 return dumpSymtab(argc - 1, argv + 1); 553 if (Subcommand == "run") 554 return run(argc - 1, argv + 1); 555 return usage(); 556 } 557