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