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> LtoOpaquePointers("lto-opaque-pointers", 171 cl::desc("Enable opaque pointer types"), 172 cl::init(true), cl::Hidden); 173 174 static cl::opt<bool> 175 DebugPassManager("debug-pass-manager", cl::Hidden, 176 cl::desc("Print pass management debugging information")); 177 178 static cl::opt<std::string> 179 StatsFile("stats-file", cl::desc("Filename to write statistics to")); 180 181 static cl::list<std::string> 182 PassPlugins("load-pass-plugin", 183 cl::desc("Load passes from plugin library")); 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 Conf.OpaquePointers = LtoOpaquePointers; 325 326 ThinBackend Backend; 327 if (ThinLTODistributedIndexes) 328 Backend = 329 createWriteIndexesThinBackend(/* OldPrefix */ "", 330 /* NewPrefix */ "", 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 Lto(std::move(Conf), std::move(Backend)); 356 357 for (std::string F : InputFilenames) { 358 std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F); 359 std::unique_ptr<InputFile> Input = 360 check(InputFile::create(MB->getMemBufferRef()), F); 361 362 std::vector<SymbolResolution> Res; 363 for (const InputFile::Symbol &Sym : Input->symbols()) { 364 auto I = CommandLineResolutions.find({F, std::string(Sym.getName())}); 365 // If it isn't found, look for ".", which would have been added 366 // (followed by a hash) when the symbol was promoted during module 367 // splitting if it was defined in one part and used in the other. 368 // Try looking up the symbol name before the suffix. 369 if (I == CommandLineResolutions.end()) { 370 auto SplitName = Sym.getName().rsplit("."); 371 I = CommandLineResolutions.find({F, std::string(SplitName.first)}); 372 } 373 if (I == CommandLineResolutions.end()) { 374 llvm::errs() << argv[0] << ": missing symbol resolution for " << F 375 << ',' << Sym.getName() << '\n'; 376 HasErrors = true; 377 } else { 378 Res.push_back(I->second.front()); 379 I->second.pop_front(); 380 if (I->second.empty()) 381 CommandLineResolutions.erase(I); 382 } 383 } 384 385 if (HasErrors) 386 continue; 387 388 MBs.push_back(std::move(MB)); 389 check(Lto.add(std::move(Input), Res), F); 390 } 391 392 if (!CommandLineResolutions.empty()) { 393 HasErrors = true; 394 for (auto UnusedRes : CommandLineResolutions) 395 llvm::errs() << argv[0] << ": unused symbol resolution for " 396 << UnusedRes.first.first << ',' << UnusedRes.first.second 397 << '\n'; 398 } 399 if (HasErrors) 400 return 1; 401 402 auto AddStream = 403 [&](size_t Task, 404 const Twine &ModuleName) -> std::unique_ptr<CachedFileStream> { 405 std::string Path = OutputFilename + "." + utostr(Task); 406 407 std::error_code EC; 408 auto S = std::make_unique<raw_fd_ostream>(Path, EC, sys::fs::OF_None); 409 check(EC, Path); 410 return std::make_unique<CachedFileStream>(std::move(S), Path); 411 }; 412 413 auto AddBuffer = [&](size_t Task, const Twine &ModuleName, 414 std::unique_ptr<MemoryBuffer> MB) { 415 *AddStream(Task, ModuleName)->OS << MB->getBuffer(); 416 }; 417 418 FileCache Cache; 419 if (!CacheDir.empty()) 420 Cache = check(localCache("ThinLTO", "Thin", CacheDir, AddBuffer), 421 "failed to create cache"); 422 423 check(Lto.run(AddStream, Cache), "LTO::run failed"); 424 return static_cast<int>(HasErrors); 425 } 426 427 static int dumpSymtab(int argc, char **argv) { 428 for (StringRef F : make_range(argv + 1, argv + argc)) { 429 std::unique_ptr<MemoryBuffer> MB = 430 check(MemoryBuffer::getFile(F), std::string(F)); 431 BitcodeFileContents BFC = 432 check(getBitcodeFileContents(*MB), std::string(F)); 433 434 if (BFC.Symtab.size() >= sizeof(irsymtab::storage::Header)) { 435 auto *Hdr = reinterpret_cast<const irsymtab::storage::Header *>( 436 BFC.Symtab.data()); 437 outs() << "version: " << Hdr->Version << '\n'; 438 if (Hdr->Version == irsymtab::storage::Header::kCurrentVersion) 439 outs() << "producer: " << Hdr->Producer.get(BFC.StrtabForSymtab) 440 << '\n'; 441 } 442 443 std::unique_ptr<InputFile> Input = 444 check(InputFile::create(MB->getMemBufferRef()), std::string(F)); 445 446 outs() << "target triple: " << Input->getTargetTriple() << '\n'; 447 Triple TT(Input->getTargetTriple()); 448 449 outs() << "source filename: " << Input->getSourceFileName() << '\n'; 450 451 if (TT.isOSBinFormatCOFF()) 452 outs() << "linker opts: " << Input->getCOFFLinkerOpts() << '\n'; 453 454 if (TT.isOSBinFormatELF()) { 455 outs() << "dependent libraries:"; 456 for (auto L : Input->getDependentLibraries()) 457 outs() << " \"" << L << "\""; 458 outs() << '\n'; 459 } 460 461 ArrayRef<std::pair<StringRef, Comdat::SelectionKind>> ComdatTable = 462 Input->getComdatTable(); 463 for (const InputFile::Symbol &Sym : Input->symbols()) { 464 switch (Sym.getVisibility()) { 465 case GlobalValue::HiddenVisibility: 466 outs() << 'H'; 467 break; 468 case GlobalValue::ProtectedVisibility: 469 outs() << 'P'; 470 break; 471 case GlobalValue::DefaultVisibility: 472 outs() << 'D'; 473 break; 474 } 475 476 auto PrintBool = [&](char C, bool B) { outs() << (B ? C : '-'); }; 477 PrintBool('U', Sym.isUndefined()); 478 PrintBool('C', Sym.isCommon()); 479 PrintBool('W', Sym.isWeak()); 480 PrintBool('I', Sym.isIndirect()); 481 PrintBool('O', Sym.canBeOmittedFromSymbolTable()); 482 PrintBool('T', Sym.isTLS()); 483 PrintBool('X', Sym.isExecutable()); 484 outs() << ' ' << Sym.getName() << '\n'; 485 486 if (Sym.isCommon()) 487 outs() << " size " << Sym.getCommonSize() << " align " 488 << Sym.getCommonAlignment() << '\n'; 489 490 int Comdat = Sym.getComdatIndex(); 491 if (Comdat != -1) { 492 outs() << " comdat "; 493 switch (ComdatTable[Comdat].second) { 494 case Comdat::Any: 495 outs() << "any"; 496 break; 497 case Comdat::ExactMatch: 498 outs() << "exactmatch"; 499 break; 500 case Comdat::Largest: 501 outs() << "largest"; 502 break; 503 case Comdat::NoDeduplicate: 504 outs() << "nodeduplicate"; 505 break; 506 case Comdat::SameSize: 507 outs() << "samesize"; 508 break; 509 } 510 outs() << ' ' << ComdatTable[Comdat].first << '\n'; 511 } 512 513 if (TT.isOSBinFormatCOFF() && Sym.isWeak() && Sym.isIndirect()) 514 outs() << " fallback " << Sym.getCOFFWeakExternalFallback() << '\n'; 515 516 if (!Sym.getSectionName().empty()) 517 outs() << " section " << Sym.getSectionName() << "\n"; 518 } 519 520 outs() << '\n'; 521 } 522 523 return 0; 524 } 525 526 int main(int argc, char **argv) { 527 InitLLVM X(argc, argv); 528 InitializeAllTargets(); 529 InitializeAllTargetMCs(); 530 InitializeAllAsmPrinters(); 531 InitializeAllAsmParsers(); 532 533 // FIXME: This should use llvm::cl subcommands, but it isn't currently 534 // possible to pass an argument not associated with a subcommand to a 535 // subcommand (e.g. -use-new-pm). 536 if (argc < 2) 537 return usage(); 538 539 StringRef Subcommand = argv[1]; 540 // Ensure that argv[0] is correct after adjusting argv/argc. 541 argv[1] = argv[0]; 542 if (Subcommand == "dump-symtab") 543 return dumpSymtab(argc - 1, argv + 1); 544 if (Subcommand == "run") 545 return run(argc - 1, argv + 1); 546 return usage(); 547 } 548