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/IR/DiagnosticPrinter.h" 21 #include "llvm/LTO/LTO.h" 22 #include "llvm/Passes/PassPlugin.h" 23 #include "llvm/Remarks/HotnessThresholdParser.h" 24 #include "llvm/Support/Caching.h" 25 #include "llvm/Support/CommandLine.h" 26 #include "llvm/Support/FileSystem.h" 27 #include "llvm/Support/InitLLVM.h" 28 #include "llvm/Support/PluginLoader.h" 29 #include "llvm/Support/TargetSelect.h" 30 #include "llvm/Support/Threading.h" 31 #include <atomic> 32 33 using namespace llvm; 34 using namespace lto; 35 36 static codegen::RegisterCodeGenFlags CGF; 37 38 static cl::opt<char> 39 OptLevel("O", 40 cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] " 41 "(default = '-O2')"), 42 cl::Prefix, cl::init('2')); 43 44 static cl::opt<char> CGOptLevel( 45 "cg-opt-level", 46 cl::desc("Codegen optimization level (0, 1, 2 or 3, default = '2')"), 47 cl::init('2')); 48 49 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore, 50 cl::desc("<input bitcode files>")); 51 52 static cl::opt<std::string> OutputFilename("o", cl::Required, 53 cl::desc("Output filename"), 54 cl::value_desc("filename")); 55 56 static cl::opt<std::string> CacheDir("cache-dir", cl::desc("Cache Directory"), 57 cl::value_desc("directory")); 58 59 static cl::opt<std::string> OptPipeline("opt-pipeline", 60 cl::desc("Optimizer Pipeline"), 61 cl::value_desc("pipeline")); 62 63 static cl::opt<std::string> AAPipeline("aa-pipeline", 64 cl::desc("Alias Analysis Pipeline"), 65 cl::value_desc("aapipeline")); 66 67 static cl::opt<bool> SaveTemps("save-temps", cl::desc("Save temporary files")); 68 69 static cl::list<std::string> SelectSaveTemps( 70 "select-save-temps", 71 cl::value_desc("One, or multiple of: " 72 "resolution,preopt,promote,internalize,import,opt,precodegen" 73 ",combinedindex"), 74 cl::desc("Save selected temporary files. Cannot be specified together with " 75 "-save-temps"), 76 cl::CommaSeparated); 77 78 constexpr const char *SaveTempsValues[] = { 79 "resolution", "preopt", "promote", "internalize", 80 "import", "opt", "precodegen", "combinedindex"}; 81 82 static cl::opt<bool> 83 ThinLTODistributedIndexes("thinlto-distributed-indexes", 84 cl::desc("Write out individual index and " 85 "import files for the " 86 "distributed backend case")); 87 88 static cl::opt<bool> 89 ThinLTOEmitIndexes("thinlto-emit-indexes", 90 cl::desc("Write out individual index files via " 91 "InProcessThinLTO")); 92 93 static cl::opt<bool> 94 ThinLTOEmitImports("thinlto-emit-imports", 95 cl::desc("Write out individual imports files via " 96 "InProcessThinLTO. Has no effect unless " 97 "specified with -thinlto-emit-indexes or " 98 "-thinlto-distributed-indexes")); 99 100 // Default to using all available threads in the system, but using only one 101 // thread per core (no SMT). 102 // Use -thinlto-threads=all to use hardware_concurrency() instead, which means 103 // to use all hardware threads or cores in the system. 104 static cl::opt<std::string> Threads("thinlto-threads"); 105 106 static cl::list<std::string> SymbolResolutions( 107 "r", 108 cl::desc("Specify a symbol resolution: filename,symbolname,resolution\n" 109 "where \"resolution\" is a sequence (which may be empty) of the\n" 110 "following characters:\n" 111 " p - prevailing: the linker has chosen this definition of the\n" 112 " symbol\n" 113 " l - local: the definition of this symbol is unpreemptable at\n" 114 " runtime and is known to be in this linkage unit\n" 115 " x - externally visible: the definition of this symbol is\n" 116 " visible outside of the LTO unit\n" 117 "A resolution for each symbol must be specified")); 118 119 static cl::opt<std::string> OverrideTriple( 120 "override-triple", 121 cl::desc("Replace target triples in input files with this triple")); 122 123 static cl::opt<std::string> DefaultTriple( 124 "default-triple", 125 cl::desc( 126 "Replace unspecified target triples in input files with this triple")); 127 128 static cl::opt<bool> RemarksWithHotness( 129 "pass-remarks-with-hotness", 130 cl::desc("With PGO, include profile count in optimization remarks"), 131 cl::Hidden); 132 133 cl::opt<std::optional<uint64_t>, false, remarks::HotnessThresholdParser> 134 RemarksHotnessThreshold( 135 "pass-remarks-hotness-threshold", 136 cl::desc("Minimum profile count required for an " 137 "optimization remark to be output." 138 " Use 'auto' to apply the threshold from profile summary."), 139 cl::value_desc("uint or 'auto'"), cl::init(0), cl::Hidden); 140 141 static cl::opt<std::string> 142 RemarksFilename("pass-remarks-output", 143 cl::desc("Output filename for pass remarks"), 144 cl::value_desc("filename")); 145 146 static cl::opt<std::string> 147 RemarksPasses("pass-remarks-filter", 148 cl::desc("Only record optimization remarks from passes whose " 149 "names match the given regular expression"), 150 cl::value_desc("regex")); 151 152 static cl::opt<std::string> RemarksFormat( 153 "pass-remarks-format", 154 cl::desc("The format used for serializing remarks (default: YAML)"), 155 cl::value_desc("format"), cl::init("yaml")); 156 157 static cl::opt<std::string> 158 SamplePGOFile("lto-sample-profile-file", 159 cl::desc("Specify a SamplePGO profile file")); 160 161 static cl::opt<std::string> 162 CSPGOFile("lto-cspgo-profile-file", 163 cl::desc("Specify a context sensitive PGO profile file")); 164 165 static cl::opt<bool> 166 RunCSIRInstr("lto-cspgo-gen", 167 cl::desc("Run PGO context sensitive IR instrumentation"), 168 cl::Hidden); 169 170 static cl::opt<bool> 171 DebugPassManager("debug-pass-manager", cl::Hidden, 172 cl::desc("Print pass management debugging information")); 173 174 static cl::opt<std::string> 175 StatsFile("stats-file", cl::desc("Filename to write statistics to")); 176 177 static cl::list<std::string> 178 PassPlugins("load-pass-plugin", 179 cl::desc("Load passes from plugin library")); 180 181 static cl::opt<std::string> UnifiedLTOMode("unified-lto", cl::Optional, 182 cl::desc("Set LTO mode"), 183 cl::value_desc("mode")); 184 185 static cl::opt<bool> EnableFreestanding( 186 "lto-freestanding", 187 cl::desc("Enable Freestanding (disable builtins / TLI) during LTO"), 188 cl::Hidden); 189 190 static cl::opt<bool> TryUseNewDbgInfoFormat( 191 "try-experimental-debuginfo-iterators", 192 cl::desc("Enable debuginfo iterator positions, if they're built in"), 193 cl::init(false), cl::Hidden); 194 195 extern cl::opt<bool> UseNewDbgInfoFormat; 196 extern cl::opt<cl::boolOrDefault> LoadBitcodeIntoNewDbgInfoFormat; 197 extern cl::opt<cl::boolOrDefault> PreserveInputDbgFormat; 198 199 static void check(Error E, std::string Msg) { 200 if (!E) 201 return; 202 handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) { 203 errs() << "llvm-lto2: " << Msg << ": " << EIB.message().c_str() << '\n'; 204 }); 205 exit(1); 206 } 207 208 template <typename T> static T check(Expected<T> E, std::string Msg) { 209 if (E) 210 return std::move(*E); 211 check(E.takeError(), Msg); 212 return T(); 213 } 214 215 static void check(std::error_code EC, std::string Msg) { 216 check(errorCodeToError(EC), Msg); 217 } 218 219 template <typename T> static T check(ErrorOr<T> E, std::string Msg) { 220 if (E) 221 return std::move(*E); 222 check(E.getError(), Msg); 223 return T(); 224 } 225 226 static int usage() { 227 errs() << "Available subcommands: dump-symtab run\n"; 228 return 1; 229 } 230 231 static int run(int argc, char **argv) { 232 cl::ParseCommandLineOptions(argc, argv, "Resolution-based LTO test harness"); 233 // Load bitcode into the new debug info format by default. 234 if (LoadBitcodeIntoNewDbgInfoFormat == cl::boolOrDefault::BOU_UNSET) 235 LoadBitcodeIntoNewDbgInfoFormat = cl::boolOrDefault::BOU_TRUE; 236 237 // RemoveDIs debug-info transition: tests may request that we /try/ to use the 238 // new debug-info format. 239 if (TryUseNewDbgInfoFormat) { 240 // Turn the new debug-info format on. 241 UseNewDbgInfoFormat = true; 242 } 243 // Since llvm-lto2 collects multiple IR modules together, for simplicity's 244 // sake we disable the "PreserveInputDbgFormat" flag to enforce a single debug 245 // info format. 246 PreserveInputDbgFormat = cl::boolOrDefault::BOU_FALSE; 247 248 // FIXME: Workaround PR30396 which means that a symbol can appear 249 // more than once if it is defined in module-level assembly and 250 // has a GV declaration. We allow (file, symbol) pairs to have multiple 251 // resolutions and apply them in the order observed. 252 std::map<std::pair<std::string, std::string>, std::list<SymbolResolution>> 253 CommandLineResolutions; 254 for (StringRef R : SymbolResolutions) { 255 StringRef Rest, FileName, SymbolName; 256 std::tie(FileName, Rest) = R.split(','); 257 if (Rest.empty()) { 258 llvm::errs() << "invalid resolution: " << R << '\n'; 259 return 1; 260 } 261 std::tie(SymbolName, Rest) = Rest.split(','); 262 SymbolResolution Res; 263 for (char C : Rest) { 264 if (C == 'p') 265 Res.Prevailing = true; 266 else if (C == 'l') 267 Res.FinalDefinitionInLinkageUnit = true; 268 else if (C == 'x') 269 Res.VisibleToRegularObj = true; 270 else if (C == 'r') 271 Res.LinkerRedefined = true; 272 else { 273 llvm::errs() << "invalid character " << C << " in resolution: " << R 274 << '\n'; 275 return 1; 276 } 277 } 278 CommandLineResolutions[{std::string(FileName), std::string(SymbolName)}] 279 .push_back(Res); 280 } 281 282 std::vector<std::unique_ptr<MemoryBuffer>> MBs; 283 284 Config Conf; 285 286 Conf.CPU = codegen::getMCPU(); 287 Conf.Options = codegen::InitTargetOptionsFromCodeGenFlags(Triple()); 288 Conf.MAttrs = codegen::getMAttrs(); 289 if (auto RM = codegen::getExplicitRelocModel()) 290 Conf.RelocModel = *RM; 291 Conf.CodeModel = codegen::getExplicitCodeModel(); 292 293 Conf.DebugPassManager = DebugPassManager; 294 295 if (SaveTemps && !SelectSaveTemps.empty()) { 296 llvm::errs() << "-save-temps cannot be specified with -select-save-temps\n"; 297 return 1; 298 } 299 if (SaveTemps || !SelectSaveTemps.empty()) { 300 DenseSet<StringRef> SaveTempsArgs; 301 for (auto &S : SelectSaveTemps) 302 if (is_contained(SaveTempsValues, S)) 303 SaveTempsArgs.insert(S); 304 else { 305 llvm::errs() << ("invalid -select-save-temps argument: " + S) << '\n'; 306 return 1; 307 } 308 check(Conf.addSaveTemps(OutputFilename + ".", false, SaveTempsArgs), 309 "Config::addSaveTemps failed"); 310 } 311 312 // Optimization remarks. 313 Conf.RemarksFilename = RemarksFilename; 314 Conf.RemarksPasses = RemarksPasses; 315 Conf.RemarksWithHotness = RemarksWithHotness; 316 Conf.RemarksHotnessThreshold = RemarksHotnessThreshold; 317 Conf.RemarksFormat = RemarksFormat; 318 319 Conf.SampleProfile = SamplePGOFile; 320 Conf.CSIRProfile = CSPGOFile; 321 Conf.RunCSIRInstr = RunCSIRInstr; 322 323 // Run a custom pipeline, if asked for. 324 Conf.OptPipeline = OptPipeline; 325 Conf.AAPipeline = AAPipeline; 326 327 Conf.OptLevel = OptLevel - '0'; 328 Conf.Freestanding = EnableFreestanding; 329 for (auto &PluginFN : PassPlugins) 330 Conf.PassPlugins.push_back(PluginFN); 331 if (auto Level = CodeGenOpt::parseLevel(CGOptLevel)) { 332 Conf.CGOptLevel = *Level; 333 } else { 334 llvm::errs() << "invalid cg optimization level: " << CGOptLevel << '\n'; 335 return 1; 336 } 337 338 if (auto FT = codegen::getExplicitFileType()) 339 Conf.CGFileType = *FT; 340 341 Conf.OverrideTriple = OverrideTriple; 342 Conf.DefaultTriple = DefaultTriple; 343 Conf.StatsFile = StatsFile; 344 Conf.PTO.LoopVectorization = Conf.OptLevel > 1; 345 Conf.PTO.SLPVectorization = Conf.OptLevel > 1; 346 347 ThinBackend Backend; 348 if (ThinLTODistributedIndexes) 349 Backend = createWriteIndexesThinBackend(/*OldPrefix=*/"", 350 /*NewPrefix=*/"", 351 /*NativeObjectPrefix=*/"", 352 ThinLTOEmitImports, 353 /*LinkedObjectsFile=*/nullptr, 354 /*OnWrite=*/{}); 355 else 356 Backend = createInProcessThinBackend( 357 llvm::heavyweight_hardware_concurrency(Threads), 358 /* OnWrite */ {}, ThinLTOEmitIndexes, ThinLTOEmitImports); 359 360 // Track whether we hit an error; in particular, in the multi-threaded case, 361 // we can't exit() early because the rest of the threads wouldn't have had a 362 // change to be join-ed, and that would result in a "terminate called without 363 // an active exception". Altogether, this results in nondeterministic 364 // behavior. Instead, we don't exit in the multi-threaded case, but we make 365 // sure to report the error and then at the end (after joining cleanly) 366 // exit(1). 367 std::atomic<bool> HasErrors; 368 std::atomic_init(&HasErrors, false); 369 Conf.DiagHandler = [&](const DiagnosticInfo &DI) { 370 DiagnosticPrinterRawOStream DP(errs()); 371 DI.print(DP); 372 errs() << '\n'; 373 if (DI.getSeverity() == DS_Error) 374 HasErrors = true; 375 }; 376 377 LTO::LTOKind LTOMode = LTO::LTOK_Default; 378 379 if (UnifiedLTOMode == "full") { 380 LTOMode = LTO::LTOK_UnifiedRegular; 381 } else if (UnifiedLTOMode == "thin") { 382 LTOMode = LTO::LTOK_UnifiedThin; 383 } else if (UnifiedLTOMode == "default") { 384 LTOMode = LTO::LTOK_Default; 385 } else if (!UnifiedLTOMode.empty()) { 386 llvm::errs() << "invalid LTO mode\n"; 387 return 1; 388 } 389 390 LTO Lto(std::move(Conf), std::move(Backend), 1, LTOMode); 391 392 for (std::string F : InputFilenames) { 393 std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F); 394 std::unique_ptr<InputFile> Input = 395 check(InputFile::create(MB->getMemBufferRef()), F); 396 397 std::vector<SymbolResolution> Res; 398 for (const InputFile::Symbol &Sym : Input->symbols()) { 399 auto I = CommandLineResolutions.find({F, std::string(Sym.getName())}); 400 // If it isn't found, look for ".", which would have been added 401 // (followed by a hash) when the symbol was promoted during module 402 // splitting if it was defined in one part and used in the other. 403 // Try looking up the symbol name before the suffix. 404 if (I == CommandLineResolutions.end()) { 405 auto SplitName = Sym.getName().rsplit("."); 406 I = CommandLineResolutions.find({F, std::string(SplitName.first)}); 407 } 408 if (I == CommandLineResolutions.end()) { 409 llvm::errs() << argv[0] << ": missing symbol resolution for " << F 410 << ',' << Sym.getName() << '\n'; 411 HasErrors = true; 412 } else { 413 Res.push_back(I->second.front()); 414 I->second.pop_front(); 415 if (I->second.empty()) 416 CommandLineResolutions.erase(I); 417 } 418 } 419 420 if (HasErrors) 421 continue; 422 423 MBs.push_back(std::move(MB)); 424 check(Lto.add(std::move(Input), Res), F); 425 } 426 427 if (!CommandLineResolutions.empty()) { 428 HasErrors = true; 429 for (auto UnusedRes : CommandLineResolutions) 430 llvm::errs() << argv[0] << ": unused symbol resolution for " 431 << UnusedRes.first.first << ',' << UnusedRes.first.second 432 << '\n'; 433 } 434 if (HasErrors) 435 return 1; 436 437 auto AddStream = 438 [&](size_t Task, 439 const Twine &ModuleName) -> std::unique_ptr<CachedFileStream> { 440 std::string Path = OutputFilename + "." + utostr(Task); 441 442 std::error_code EC; 443 auto S = std::make_unique<raw_fd_ostream>(Path, EC, sys::fs::OF_None); 444 check(EC, Path); 445 return std::make_unique<CachedFileStream>(std::move(S), Path); 446 }; 447 448 auto AddBuffer = [&](size_t Task, const Twine &ModuleName, 449 std::unique_ptr<MemoryBuffer> MB) { 450 *AddStream(Task, ModuleName)->OS << MB->getBuffer(); 451 }; 452 453 FileCache Cache; 454 if (!CacheDir.empty()) 455 Cache = check(localCache("ThinLTO", "Thin", CacheDir, AddBuffer), 456 "failed to create cache"); 457 458 check(Lto.run(AddStream, Cache), "LTO::run failed"); 459 return static_cast<int>(HasErrors); 460 } 461 462 static int dumpSymtab(int argc, char **argv) { 463 for (StringRef F : make_range(argv + 1, argv + argc)) { 464 std::unique_ptr<MemoryBuffer> MB = 465 check(MemoryBuffer::getFile(F), std::string(F)); 466 BitcodeFileContents BFC = 467 check(getBitcodeFileContents(*MB), std::string(F)); 468 469 if (BFC.Symtab.size() >= sizeof(irsymtab::storage::Header)) { 470 auto *Hdr = reinterpret_cast<const irsymtab::storage::Header *>( 471 BFC.Symtab.data()); 472 outs() << "version: " << Hdr->Version << '\n'; 473 if (Hdr->Version == irsymtab::storage::Header::kCurrentVersion) 474 outs() << "producer: " << Hdr->Producer.get(BFC.StrtabForSymtab) 475 << '\n'; 476 } 477 478 std::unique_ptr<InputFile> Input = 479 check(InputFile::create(MB->getMemBufferRef()), std::string(F)); 480 481 outs() << "target triple: " << Input->getTargetTriple() << '\n'; 482 Triple TT(Input->getTargetTriple()); 483 484 outs() << "source filename: " << Input->getSourceFileName() << '\n'; 485 486 if (TT.isOSBinFormatCOFF()) 487 outs() << "linker opts: " << Input->getCOFFLinkerOpts() << '\n'; 488 489 if (TT.isOSBinFormatELF()) { 490 outs() << "dependent libraries:"; 491 for (auto L : Input->getDependentLibraries()) 492 outs() << " \"" << L << "\""; 493 outs() << '\n'; 494 } 495 496 ArrayRef<std::pair<StringRef, Comdat::SelectionKind>> ComdatTable = 497 Input->getComdatTable(); 498 for (const InputFile::Symbol &Sym : Input->symbols()) { 499 switch (Sym.getVisibility()) { 500 case GlobalValue::HiddenVisibility: 501 outs() << 'H'; 502 break; 503 case GlobalValue::ProtectedVisibility: 504 outs() << 'P'; 505 break; 506 case GlobalValue::DefaultVisibility: 507 outs() << 'D'; 508 break; 509 } 510 511 auto PrintBool = [&](char C, bool B) { outs() << (B ? C : '-'); }; 512 PrintBool('U', Sym.isUndefined()); 513 PrintBool('C', Sym.isCommon()); 514 PrintBool('W', Sym.isWeak()); 515 PrintBool('I', Sym.isIndirect()); 516 PrintBool('O', Sym.canBeOmittedFromSymbolTable()); 517 PrintBool('T', Sym.isTLS()); 518 PrintBool('X', Sym.isExecutable()); 519 outs() << ' ' << Sym.getName() << '\n'; 520 521 if (Sym.isCommon()) 522 outs() << " size " << Sym.getCommonSize() << " align " 523 << Sym.getCommonAlignment() << '\n'; 524 525 int Comdat = Sym.getComdatIndex(); 526 if (Comdat != -1) { 527 outs() << " comdat "; 528 switch (ComdatTable[Comdat].second) { 529 case Comdat::Any: 530 outs() << "any"; 531 break; 532 case Comdat::ExactMatch: 533 outs() << "exactmatch"; 534 break; 535 case Comdat::Largest: 536 outs() << "largest"; 537 break; 538 case Comdat::NoDeduplicate: 539 outs() << "nodeduplicate"; 540 break; 541 case Comdat::SameSize: 542 outs() << "samesize"; 543 break; 544 } 545 outs() << ' ' << ComdatTable[Comdat].first << '\n'; 546 } 547 548 if (TT.isOSBinFormatCOFF() && Sym.isWeak() && Sym.isIndirect()) 549 outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n'; 550 551 if (!Sym.getSectionName().empty()) 552 outs() << " section " << Sym.getSectionName() << "\n"; 553 } 554 555 outs() << '\n'; 556 } 557 558 return 0; 559 } 560 561 int main(int argc, char **argv) { 562 InitLLVM X(argc, argv); 563 InitializeAllTargets(); 564 InitializeAllTargetMCs(); 565 InitializeAllAsmPrinters(); 566 InitializeAllAsmParsers(); 567 568 // FIXME: This should use llvm::cl subcommands, but it isn't currently 569 // possible to pass an argument not associated with a subcommand to a 570 // subcommand (e.g. -use-new-pm). 571 if (argc < 2) 572 return usage(); 573 574 StringRef Subcommand = argv[1]; 575 // Ensure that argv[0] is correct after adjusting argv/argc. 576 argv[1] = argv[0]; 577 if (Subcommand == "dump-symtab") 578 return dumpSymtab(argc - 1, argv + 1); 579 if (Subcommand == "run") 580 return run(argc - 1, argv + 1); 581 return usage(); 582 } 583