llvm/tools/llvm-lto2/llvm-lto2.cpp

   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 }