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.inc"
  20 #include "llvm/IR/DiagnosticPrinter.h"
  21 #include "llvm/LTO/Caching.h"
  22 #include "llvm/LTO/LTO.h"
  23 #include "llvm/Support/CommandLine.h"
  24 #include "llvm/Support/FileSystem.h"
  25 #include "llvm/Support/InitLLVM.h"
  26 #include "llvm/Support/TargetSelect.h"
  27 #include "llvm/Support/Threading.h"
  28
  29 using namespace llvm;
  30 using namespace lto;
  31
  32 static cl::opt<char>
  33     OptLevel("O", cl::desc("Optimization level. [-O0, -O1, -O2, or -O3] "
  34                            "(default = '-O2')"),
  35              cl::Prefix, cl::ZeroOrMore, cl::init('2'));
  36
  37 static cl::opt<char> CGOptLevel(
  38     "cg-opt-level",
  39     cl::desc("Codegen optimization level (0, 1, 2 or 3, default = '2')"),
  40     cl::init('2'));
  41
  42 static cl::list<std::string> InputFilenames(cl::Positional, cl::OneOrMore,
  43                                             cl::desc("<input bitcode files>"));
  44
  45 static cl::opt<std::string> OutputFilename("o", cl::Required,
  46                                            cl::desc("Output filename"),
  47                                            cl::value_desc("filename"));
  48
  49 static cl::opt<std::string> CacheDir("cache-dir", cl::desc("Cache Directory"),
  50                                      cl::value_desc("directory"));
  51
  52 static cl::opt<std::string> OptPipeline("opt-pipeline",
  53                                         cl::desc("Optimizer Pipeline"),
  54                                         cl::value_desc("pipeline"));
  55
  56 static cl::opt<std::string> AAPipeline("aa-pipeline",
  57                                        cl::desc("Alias Analysis Pipeline"),
  58                                        cl::value_desc("aapipeline"));
  59
  60 static cl::opt<bool> SaveTemps("save-temps", cl::desc("Save temporary files"));
  61
  62 static cl::opt<bool>
  63     ThinLTODistributedIndexes("thinlto-distributed-indexes", cl::init(false),
  64                               cl::desc("Write out individual index and "
  65                                        "import files for the "
  66                                        "distributed backend case"));
  67
  68 static cl::opt<int> Threads("thinlto-threads",
  69                             cl::init(llvm::heavyweight_hardware_concurrency()));
  70
  71 static cl::list<std::string> SymbolResolutions(
  72     "r",
  73     cl::desc("Specify a symbol resolution: filename,symbolname,resolution\n"
  74              "where \"resolution\" is a sequence (which may be empty) of the\n"
  75              "following characters:\n"
  76              " p - prevailing: the linker has chosen this definition of the\n"
  77              "     symbol\n"
  78              " l - local: the definition of this symbol is unpreemptable at\n"
  79              "     runtime and is known to be in this linkage unit\n"
  80              " x - externally visible: the definition of this symbol is\n"
  81              "     visible outside of the LTO unit\n"
  82              "A resolution for each symbol must be specified."),
  83     cl::ZeroOrMore);
  84
  85 static cl::opt<std::string> OverrideTriple(
  86     "override-triple",
  87     cl::desc("Replace target triples in input files with this triple"));
  88
  89 static cl::opt<std::string> DefaultTriple(
  90     "default-triple",
  91     cl::desc(
  92         "Replace unspecified target triples in input files with this triple"));
  93
  94 static cl::opt<std::string>
  95     OptRemarksOutput("pass-remarks-output",
  96                      cl::desc("YAML output file for optimization remarks"));
  97
  98 static cl::opt<bool> OptRemarksWithHotness(
  99     "pass-remarks-with-hotness",
 100     cl::desc("Whether to include hotness informations in the remarks.\n"
 101              "Has effect only if -pass-remarks-output is specified."));
 102
 103 static cl::opt<std::string>
 104     SamplePGOFile("lto-sample-profile-file",
 105                   cl::desc("Specify a SamplePGO profile file"));
 106
 107 static cl::opt<bool>
 108     UseNewPM("use-new-pm",
 109              cl::desc("Run LTO passes using the new pass manager"),
 110              cl::init(false), cl::Hidden);
 111
 112 static cl::opt<bool>
 113     DebugPassManager("debug-pass-manager", cl::init(false), cl::Hidden,
 114                      cl::desc("Print pass management debugging information"));
 115
 116 static cl::opt<std::string>
 117     StatsFile("stats-file", cl::desc("Filename to write statistics to"));
 118
 119 static void check(Error E, std::string Msg) {
 120   if (!E)
 121     return;
 122   handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
 123     errs() << "llvm-lto2: " << Msg << ": " << EIB.message().c_str() << '\n';
 124   });
 125   exit(1);
 126 }
 127
 128 template <typename T> static T check(Expected<T> E, std::string Msg) {
 129   if (E)
 130     return std::move(*E);
 131   check(E.takeError(), Msg);
 132   return T();
 133 }
 134
 135 static void check(std::error_code EC, std::string Msg) {
 136   check(errorCodeToError(EC), Msg);
 137 }
 138
 139 template <typename T> static T check(ErrorOr<T> E, std::string Msg) {
 140   if (E)
 141     return std::move(*E);
 142   check(E.getError(), Msg);
 143   return T();
 144 }
 145
 146 static int usage() {
 147   errs() << "Available subcommands: dump-symtab run\n";
 148   return 1;
 149 }
 150
 151 static int run(int argc, char **argv) {
 152   cl::ParseCommandLineOptions(argc, argv, "Resolution-based LTO test harness");
 153
 154   // FIXME: Workaround PR30396 which means that a symbol can appear
 155   // more than once if it is defined in module-level assembly and
 156   // has a GV declaration. We allow (file, symbol) pairs to have multiple
 157   // resolutions and apply them in the order observed.
 158   std::map<std::pair<std::string, std::string>, std::list<SymbolResolution>>
 159       CommandLineResolutions;
 160   for (std::string R : SymbolResolutions) {
 161     StringRef Rest = R;
 162     StringRef FileName, SymbolName;
 163     std::tie(FileName, Rest) = Rest.split(',');
 164     if (Rest.empty()) {
 165       llvm::errs() << "invalid resolution: " << R << '\n';
 166       return 1;
 167     }
 168     std::tie(SymbolName, Rest) = Rest.split(',');
 169     SymbolResolution Res;
 170     for (char C : Rest) {
 171       if (C == 'p')
 172         Res.Prevailing = true;
 173       else if (C == 'l')
 174         Res.FinalDefinitionInLinkageUnit = true;
 175       else if (C == 'x')
 176         Res.VisibleToRegularObj = true;
 177       else if (C == 'r')
 178         Res.LinkerRedefined = true;
 179       else {
 180         llvm::errs() << "invalid character " << C << " in resolution: " << R
 181                      << '\n';
 182         return 1;
 183       }
 184     }
 185     CommandLineResolutions[{FileName, SymbolName}].push_back(Res);
 186   }
 187
 188   std::vector<std::unique_ptr<MemoryBuffer>> MBs;
 189
 190   Config Conf;
 191   Conf.DiagHandler = [](const DiagnosticInfo &DI) {
 192     DiagnosticPrinterRawOStream DP(errs());
 193     DI.print(DP);
 194     errs() << '\n';
 195     if (DI.getSeverity() == DS_Error)
 196       exit(1);
 197   };
 198
 199   Conf.CPU = MCPU;
 200   Conf.Options = InitTargetOptionsFromCodeGenFlags();
 201   Conf.MAttrs = MAttrs;
 202   if (auto RM = getRelocModel())
 203     Conf.RelocModel = *RM;
 204   Conf.CodeModel = getCodeModel();
 205
 206   Conf.DebugPassManager = DebugPassManager;
 207
 208   if (SaveTemps)
 209     check(Conf.addSaveTemps(OutputFilename + "."),
 210           "Config::addSaveTemps failed");
 211
 212   // Optimization remarks.
 213   Conf.RemarksFilename = OptRemarksOutput;
 214   Conf.RemarksWithHotness = OptRemarksWithHotness;
 215
 216   Conf.SampleProfile = SamplePGOFile;
 217
 218   // Run a custom pipeline, if asked for.
 219   Conf.OptPipeline = OptPipeline;
 220   Conf.AAPipeline = AAPipeline;
 221
 222   Conf.OptLevel = OptLevel - '0';
 223   Conf.UseNewPM = UseNewPM;
 224   switch (CGOptLevel) {
 225   case '0':
 226     Conf.CGOptLevel = CodeGenOpt::None;
 227     break;
 228   case '1':
 229     Conf.CGOptLevel = CodeGenOpt::Less;
 230     break;
 231   case '2':
 232     Conf.CGOptLevel = CodeGenOpt::Default;
 233     break;
 234   case '3':
 235     Conf.CGOptLevel = CodeGenOpt::Aggressive;
 236     break;
 237   default:
 238     llvm::errs() << "invalid cg optimization level: " << CGOptLevel << '\n';
 239     return 1;
 240   }
 241
 242   if (FileType.getNumOccurrences())
 243     Conf.CGFileType = FileType;
 244
 245   Conf.OverrideTriple = OverrideTriple;
 246   Conf.DefaultTriple = DefaultTriple;
 247   Conf.StatsFile = StatsFile;
 248
 249   ThinBackend Backend;
 250   if (ThinLTODistributedIndexes)
 251     Backend = createWriteIndexesThinBackend(/* OldPrefix */ "",
 252                                             /* NewPrefix */ "",
 253                                             /* ShouldEmitImportsFiles */ true,
 254                                             /* LinkedObjectsFile */ nullptr,
 255                                             /* OnWrite */ {});
 256   else
 257     Backend = createInProcessThinBackend(Threads);
 258   LTO Lto(std::move(Conf), std::move(Backend));
 259
 260   bool HasErrors = false;
 261   for (std::string F : InputFilenames) {
 262     std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F);
 263     std::unique_ptr<InputFile> Input =
 264         check(InputFile::create(MB->getMemBufferRef()), F);
 265
 266     std::vector<SymbolResolution> Res;
 267     for (const InputFile::Symbol &Sym : Input->symbols()) {
 268       auto I = CommandLineResolutions.find({F, Sym.getName()});
 269       if (I == CommandLineResolutions.end()) {
 270         llvm::errs() << argv[0] << ": missing symbol resolution for " << F
 271                      << ',' << Sym.getName() << '\n';
 272         HasErrors = true;
 273       } else {
 274         Res.push_back(I->second.front());
 275         I->second.pop_front();
 276         if (I->second.empty())
 277           CommandLineResolutions.erase(I);
 278       }
 279     }
 280
 281     if (HasErrors)
 282       continue;
 283
 284     MBs.push_back(std::move(MB));
 285     check(Lto.add(std::move(Input), Res), F);
 286   }
 287
 288   if (!CommandLineResolutions.empty()) {
 289     HasErrors = true;
 290     for (auto UnusedRes : CommandLineResolutions)
 291       llvm::errs() << argv[0] << ": unused symbol resolution for "
 292                    << UnusedRes.first.first << ',' << UnusedRes.first.second
 293                    << '\n';
 294   }
 295   if (HasErrors)
 296     return 1;
 297
 298   auto AddStream =
 299       [&](size_t Task) -> std::unique_ptr<lto::NativeObjectStream> {
 300     std::string Path = OutputFilename + "." + utostr(Task);
 301
 302     std::error_code EC;
 303     auto S = llvm::make_unique<raw_fd_ostream>(Path, EC, sys::fs::F_None);
 304     check(EC, Path);
 305     return llvm::make_unique<lto::NativeObjectStream>(std::move(S));
 306   };
 307
 308   auto AddBuffer = [&](size_t Task, std::unique_ptr<MemoryBuffer> MB) {
 309     *AddStream(Task)->OS << MB->getBuffer();
 310   };
 311
 312   NativeObjectCache Cache;
 313   if (!CacheDir.empty())
 314     Cache = check(localCache(CacheDir, AddBuffer), "failed to create cache");
 315
 316   check(Lto.run(AddStream, Cache), "LTO::run failed");
 317   return 0;
 318 }
 319
 320 static int dumpSymtab(int argc, char **argv) {
 321   for (StringRef F : make_range(argv + 1, argv + argc)) {
 322     std::unique_ptr<MemoryBuffer> MB = check(MemoryBuffer::getFile(F), F);
 323     BitcodeFileContents BFC = check(getBitcodeFileContents(*MB), F);
 324
 325     if (BFC.Symtab.size() >= sizeof(irsymtab::storage::Header)) {
 326       auto *Hdr = reinterpret_cast<const irsymtab::storage::Header *>(
 327           BFC.Symtab.data());
 328       outs() << "version: " << Hdr->Version << '\n';
 329       if (Hdr->Version == irsymtab::storage::Header::kCurrentVersion)
 330         outs() << "producer: " << Hdr->Producer.get(BFC.StrtabForSymtab)
 331                << '\n';
 332     }
 333
 334     std::unique_ptr<InputFile> Input =
 335         check(InputFile::create(MB->getMemBufferRef()), F);
 336
 337     outs() << "target triple: " << Input->getTargetTriple() << '\n';
 338     Triple TT(Input->getTargetTriple());
 339
 340     outs() << "source filename: " << Input->getSourceFileName() << '\n';
 341
 342     if (TT.isOSBinFormatCOFF())
 343       outs() << "linker opts: " << Input->getCOFFLinkerOpts() << '\n';
 344
 345     std::vector<StringRef> ComdatTable = Input->getComdatTable();
 346     for (const InputFile::Symbol &Sym : Input->symbols()) {
 347       switch (Sym.getVisibility()) {
 348       case GlobalValue::HiddenVisibility:
 349         outs() << 'H';
 350         break;
 351       case GlobalValue::ProtectedVisibility:
 352         outs() << 'P';
 353         break;
 354       case GlobalValue::DefaultVisibility:
 355         outs() << 'D';
 356         break;
 357       }
 358
 359       auto PrintBool = [&](char C, bool B) { outs() << (B ? C : '-'); };
 360       PrintBool('U', Sym.isUndefined());
 361       PrintBool('C', Sym.isCommon());
 362       PrintBool('W', Sym.isWeak());
 363       PrintBool('I', Sym.isIndirect());
 364       PrintBool('O', Sym.canBeOmittedFromSymbolTable());
 365       PrintBool('T', Sym.isTLS());
 366       PrintBool('X', Sym.isExecutable());
 367       outs() << ' ' << Sym.getName() << '\n';
 368
 369       if (Sym.isCommon())
 370         outs() << "         size " << Sym.getCommonSize() << " align "
 371                << Sym.getCommonAlignment() << '\n';
 372
 373       int Comdat = Sym.getComdatIndex();
 374       if (Comdat != -1)
 375         outs() << "         comdat " << ComdatTable[Comdat] << '\n';
 376
 377       if (TT.isOSBinFormatCOFF() && Sym.isWeak() && Sym.isIndirect())
 378         outs() << "         fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
 379
 380       if (!Sym.getSectionName().empty())
 381         outs() << "         section " << Sym.getSectionName() << "\n";
 382     }
 383
 384     outs() << '\n';
 385   }
 386
 387   return 0;
 388 }
 389
 390 int main(int argc, char **argv) {
 391   InitLLVM X(argc, argv);
 392   InitializeAllTargets();
 393   InitializeAllTargetMCs();
 394   InitializeAllAsmPrinters();
 395   InitializeAllAsmParsers();
 396
 397   // FIXME: This should use llvm::cl subcommands, but it isn't currently
 398   // possible to pass an argument not associated with a subcommand to a
 399   // subcommand (e.g. -use-new-pm).
 400   if (argc < 2)
 401     return usage();
 402
 403   StringRef Subcommand = argv[1];
 404   // Ensure that argv[0] is correct after adjusting argv/argc.
 405   argv[1] = argv[0];
 406   if (Subcommand == "dump-symtab")
 407     return dumpSymtab(argc - 1, argv + 1);
 408   if (Subcommand == "run")
 409     return run(argc - 1, argv + 1);
 410   return usage();
 411 }