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 void check(Error E, std::string Msg) { 191 if (!E) 192 return; 193 handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) { 194 errs() << "llvm-lto2: " << Msg << ": " << EIB.message().c_str() << '\n'; 195 }); 196 exit(1); 197 } 198 199 template <typename T> static T check(Expected<T> E, std::string Msg) { 200 if (E) 201 return std::move(*E); 202 check(E.takeError(), Msg); 203 return T(); 204 } 205 206 static void check(std::error_code EC, std::string Msg) { 207 check(errorCodeToError(EC), Msg); 208 } 209 210 template <typename T> static T check(ErrorOr<T> E, std::string Msg) { 211 if (E) 212 return std::move(*E); 213 check(E.getError(), Msg); 214 return T(); 215 } 216 217 static int usage() { 218 errs() << "Available subcommands: dump-symtab run\n"; 219 return 1; 220 } 221 222 static int run(int argc, char **argv) { 223 cl::ParseCommandLineOptions(argc, argv, "Resolution-based LTO test harness"); 224 225 // FIXME: Workaround PR30396 which means that a symbol can appear 226 // more than once if it is defined in module-level assembly and 227 // has a GV declaration. We allow (file, symbol) pairs to have multiple 228 // resolutions and apply them in the order observed. 229 std::map<std::pair<std::string, std::string>, std::list<SymbolResolution>> 230 CommandLineResolutions; 231 for (std::string R : SymbolResolutions) { 232 StringRef Rest = R; 233 StringRef FileName, SymbolName; 234 std::tie(FileName, Rest) = Rest.split(','); 235 if (Rest.empty()) { 236 llvm::errs() << "invalid resolution: " << R << '\n'; 237 return 1; 238 } 239 std::tie(SymbolName, Rest) = Rest.split(','); 240 SymbolResolution Res; 241 for (char C : Rest) { 242 if (C == 'p') 243 Res.Prevailing = true; 244 else if (C == 'l') 245 Res.FinalDefinitionInLinkageUnit = true; 246 else if (C == 'x') 247 Res.VisibleToRegularObj = true; 248 else if (C == 'r') 249 Res.LinkerRedefined = true; 250 else { 251 llvm::errs() << "invalid character " << C << " in resolution: " << R 252 << '\n'; 253 return 1; 254 } 255 } 256 CommandLineResolutions[{std::string(FileName), std::string(SymbolName)}] 257 .push_back(Res); 258 } 259 260 std::vector<std::unique_ptr<MemoryBuffer>> MBs; 261 262 Config Conf; 263 264 Conf.CPU = codegen::getMCPU(); 265 Conf.Options = codegen::InitTargetOptionsFromCodeGenFlags(Triple()); 266 Conf.MAttrs = codegen::getMAttrs(); 267 if (auto RM = codegen::getExplicitRelocModel()) 268 Conf.RelocModel = *RM; 269 Conf.CodeModel = codegen::getExplicitCodeModel(); 270 271 Conf.DebugPassManager = DebugPassManager; 272 273 if (SaveTemps && !SelectSaveTemps.empty()) { 274 llvm::errs() << "-save-temps cannot be specified with -select-save-temps\n"; 275 return 1; 276 } 277 if (SaveTemps || !SelectSaveTemps.empty()) { 278 DenseSet<StringRef> SaveTempsArgs; 279 for (auto &S : SelectSaveTemps) 280 if (is_contained(SaveTempsValues, S)) 281 SaveTempsArgs.insert(S); 282 else { 283 llvm::errs() << ("invalid -select-save-temps argument: " + S) << '\n'; 284 return 1; 285 } 286 check(Conf.addSaveTemps(OutputFilename + ".", false, SaveTempsArgs), 287 "Config::addSaveTemps failed"); 288 } 289 290 // Optimization remarks. 291 Conf.RemarksFilename = RemarksFilename; 292 Conf.RemarksPasses = RemarksPasses; 293 Conf.RemarksWithHotness = RemarksWithHotness; 294 Conf.RemarksHotnessThreshold = RemarksHotnessThreshold; 295 Conf.RemarksFormat = RemarksFormat; 296 297 Conf.SampleProfile = SamplePGOFile; 298 Conf.CSIRProfile = CSPGOFile; 299 Conf.RunCSIRInstr = RunCSIRInstr; 300 301 // Run a custom pipeline, if asked for. 302 Conf.OptPipeline = OptPipeline; 303 Conf.AAPipeline = AAPipeline; 304 305 Conf.OptLevel = OptLevel - '0'; 306 Conf.Freestanding = EnableFreestanding; 307 for (auto &PluginFN : PassPlugins) 308 Conf.PassPlugins.push_back(PluginFN); 309 if (auto Level = CodeGenOpt::parseLevel(CGOptLevel)) { 310 Conf.CGOptLevel = *Level; 311 } else { 312 llvm::errs() << "invalid cg optimization level: " << CGOptLevel << '\n'; 313 return 1; 314 } 315 316 if (auto FT = codegen::getExplicitFileType()) 317 Conf.CGFileType = *FT; 318 319 Conf.OverrideTriple = OverrideTriple; 320 Conf.DefaultTriple = DefaultTriple; 321 Conf.StatsFile = StatsFile; 322 Conf.PTO.LoopVectorization = Conf.OptLevel > 1; 323 Conf.PTO.SLPVectorization = Conf.OptLevel > 1; 324 325 ThinBackend Backend; 326 if (ThinLTODistributedIndexes) 327 Backend = createWriteIndexesThinBackend(/*OldPrefix=*/"", 328 /*NewPrefix=*/"", 329 /*NativeObjectPrefix=*/"", 330 ThinLTOEmitImports, 331 /*LinkedObjectsFile=*/nullptr, 332 /*OnWrite=*/{}); 333 else 334 Backend = createInProcessThinBackend( 335 llvm::heavyweight_hardware_concurrency(Threads), 336 /* OnWrite */ {}, ThinLTOEmitIndexes, ThinLTOEmitImports); 337 338 // Track whether we hit an error; in particular, in the multi-threaded case, 339 // we can't exit() early because the rest of the threads wouldn't have had a 340 // change to be join-ed, and that would result in a "terminate called without 341 // an active exception". Altogether, this results in nondeterministic 342 // behavior. Instead, we don't exit in the multi-threaded case, but we make 343 // sure to report the error and then at the end (after joining cleanly) 344 // exit(1). 345 std::atomic<bool> HasErrors; 346 std::atomic_init(&HasErrors, false); 347 Conf.DiagHandler = [&](const DiagnosticInfo &DI) { 348 DiagnosticPrinterRawOStream DP(errs()); 349 DI.print(DP); 350 errs() << '\n'; 351 if (DI.getSeverity() == DS_Error) 352 HasErrors = true; 353 }; 354 355 LTO::LTOKind LTOMode = LTO::LTOK_Default; 356 357 if (UnifiedLTOMode == "full") { 358 LTOMode = LTO::LTOK_UnifiedRegular; 359 } else if (UnifiedLTOMode == "thin") { 360 LTOMode = LTO::LTOK_UnifiedThin; 361 } else if (UnifiedLTOMode == "default") { 362 LTOMode = LTO::LTOK_Default; 363 } else if (!UnifiedLTOMode.empty()) { 364 llvm::errs() << "invalid LTO mode\n"; 365 return 1; 366 } 367 368 LTO Lto(std::move(Conf), std::move(Backend), 1, LTOMode); 369 370 for (std::string F : InputFilenames) { 371 std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F); 372 std::unique_ptr<InputFile> Input = 373 check(InputFile::create(MB->getMemBufferRef()), F); 374 375 std::vector<SymbolResolution> Res; 376 for (const InputFile::Symbol &Sym : Input->symbols()) { 377 auto I = CommandLineResolutions.find({F, std::string(Sym.getName())}); 378 // If it isn't found, look for ".", which would have been added 379 // (followed by a hash) when the symbol was promoted during module 380 // splitting if it was defined in one part and used in the other. 381 // Try looking up the symbol name before the suffix. 382 if (I == CommandLineResolutions.end()) { 383 auto SplitName = Sym.getName().rsplit("."); 384 I = CommandLineResolutions.find({F, std::string(SplitName.first)}); 385 } 386 if (I == CommandLineResolutions.end()) { 387 llvm::errs() << argv[0] << ": missing symbol resolution for " << F 388 << ',' << Sym.getName() << '\n'; 389 HasErrors = true; 390 } else { 391 Res.push_back(I->second.front()); 392 I->second.pop_front(); 393 if (I->second.empty()) 394 CommandLineResolutions.erase(I); 395 } 396 } 397 398 if (HasErrors) 399 continue; 400 401 MBs.push_back(std::move(MB)); 402 check(Lto.add(std::move(Input), Res), F); 403 } 404 405 if (!CommandLineResolutions.empty()) { 406 HasErrors = true; 407 for (auto UnusedRes : CommandLineResolutions) 408 llvm::errs() << argv[0] << ": unused symbol resolution for " 409 << UnusedRes.first.first << ',' << UnusedRes.first.second 410 << '\n'; 411 } 412 if (HasErrors) 413 return 1; 414 415 auto AddStream = 416 [&](size_t Task, 417 const Twine &ModuleName) -> std::unique_ptr<CachedFileStream> { 418 std::string Path = OutputFilename + "." + utostr(Task); 419 420 std::error_code EC; 421 auto S = std::make_unique<raw_fd_ostream>(Path, EC, sys::fs::OF_None); 422 check(EC, Path); 423 return std::make_unique<CachedFileStream>(std::move(S), Path); 424 }; 425 426 auto AddBuffer = [&](size_t Task, const Twine &ModuleName, 427 std::unique_ptr<MemoryBuffer> MB) { 428 *AddStream(Task, ModuleName)->OS << MB->getBuffer(); 429 }; 430 431 FileCache Cache; 432 if (!CacheDir.empty()) 433 Cache = check(localCache("ThinLTO", "Thin", CacheDir, AddBuffer), 434 "failed to create cache"); 435 436 check(Lto.run(AddStream, Cache), "LTO::run failed"); 437 return static_cast<int>(HasErrors); 438 } 439 440 static int dumpSymtab(int argc, char **argv) { 441 for (StringRef F : make_range(argv + 1, argv + argc)) { 442 std::unique_ptr<MemoryBuffer> MB = 443 check(MemoryBuffer::getFile(F), std::string(F)); 444 BitcodeFileContents BFC = 445 check(getBitcodeFileContents(*MB), std::string(F)); 446 447 if (BFC.Symtab.size() >= sizeof(irsymtab::storage::Header)) { 448 auto *Hdr = reinterpret_cast<const irsymtab::storage::Header *>( 449 BFC.Symtab.data()); 450 outs() << "version: " << Hdr->Version << '\n'; 451 if (Hdr->Version == irsymtab::storage::Header::kCurrentVersion) 452 outs() << "producer: " << Hdr->Producer.get(BFC.StrtabForSymtab) 453 << '\n'; 454 } 455 456 std::unique_ptr<InputFile> Input = 457 check(InputFile::create(MB->getMemBufferRef()), std::string(F)); 458 459 outs() << "target triple: " << Input->getTargetTriple() << '\n'; 460 Triple TT(Input->getTargetTriple()); 461 462 outs() << "source filename: " << Input->getSourceFileName() << '\n'; 463 464 if (TT.isOSBinFormatCOFF()) 465 outs() << "linker opts: " << Input->getCOFFLinkerOpts() << '\n'; 466 467 if (TT.isOSBinFormatELF()) { 468 outs() << "dependent libraries:"; 469 for (auto L : Input->getDependentLibraries()) 470 outs() << " \"" << L << "\""; 471 outs() << '\n'; 472 } 473 474 ArrayRef<std::pair<StringRef, Comdat::SelectionKind>> ComdatTable = 475 Input->getComdatTable(); 476 for (const InputFile::Symbol &Sym : Input->symbols()) { 477 switch (Sym.getVisibility()) { 478 case GlobalValue::HiddenVisibility: 479 outs() << 'H'; 480 break; 481 case GlobalValue::ProtectedVisibility: 482 outs() << 'P'; 483 break; 484 case GlobalValue::DefaultVisibility: 485 outs() << 'D'; 486 break; 487 } 488 489 auto PrintBool = [&](char C, bool B) { outs() << (B ? C : '-'); }; 490 PrintBool('U', Sym.isUndefined()); 491 PrintBool('C', Sym.isCommon()); 492 PrintBool('W', Sym.isWeak()); 493 PrintBool('I', Sym.isIndirect()); 494 PrintBool('O', Sym.canBeOmittedFromSymbolTable()); 495 PrintBool('T', Sym.isTLS()); 496 PrintBool('X', Sym.isExecutable()); 497 outs() << ' ' << Sym.getName() << '\n'; 498 499 if (Sym.isCommon()) 500 outs() << " size " << Sym.getCommonSize() << " align " 501 << Sym.getCommonAlignment() << '\n'; 502 503 int Comdat = Sym.getComdatIndex(); 504 if (Comdat != -1) { 505 outs() << " comdat "; 506 switch (ComdatTable[Comdat].second) { 507 case Comdat::Any: 508 outs() << "any"; 509 break; 510 case Comdat::ExactMatch: 511 outs() << "exactmatch"; 512 break; 513 case Comdat::Largest: 514 outs() << "largest"; 515 break; 516 case Comdat::NoDeduplicate: 517 outs() << "nodeduplicate"; 518 break; 519 case Comdat::SameSize: 520 outs() << "samesize"; 521 break; 522 } 523 outs() << ' ' << ComdatTable[Comdat].first << '\n'; 524 } 525 526 if (TT.isOSBinFormatCOFF() && Sym.isWeak() && Sym.isIndirect()) 527 outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n'; 528 529 if (!Sym.getSectionName().empty()) 530 outs() << " section " << Sym.getSectionName() << "\n"; 531 } 532 533 outs() << '\n'; 534 } 535 536 return 0; 537 } 538 539 int main(int argc, char **argv) { 540 InitLLVM X(argc, argv); 541 InitializeAllTargets(); 542 InitializeAllTargetMCs(); 543 InitializeAllAsmPrinters(); 544 InitializeAllAsmParsers(); 545 546 // FIXME: This should use llvm::cl subcommands, but it isn't currently 547 // possible to pass an argument not associated with a subcommand to a 548 // subcommand (e.g. -use-new-pm). 549 if (argc < 2) 550 return usage(); 551 552 StringRef Subcommand = argv[1]; 553 // Ensure that argv[0] is correct after adjusting argv/argc. 554 argv[1] = argv[0]; 555 if (Subcommand == "dump-symtab") 556 return dumpSymtab(argc - 1, argv + 1); 557 if (Subcommand == "run") 558 return run(argc - 1, argv + 1); 559 return usage(); 560 } 561