lld/MachO/DriverUtils.cpp

   1 //===- DriverUtils.cpp ----------------------------------------------------===//
   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 #include "Config.h"
  10 #include "Driver.h"
  11 #include "InputFiles.h"
  12 #include "ObjC.h"
  13 #include "Target.h"
  14
  15 #include "lld/Common/Args.h"
  16 #include "lld/Common/CommonLinkerContext.h"
  17 #include "lld/Common/Reproduce.h"
  18 #include "llvm/ADT/CachedHashString.h"
  19 #include "llvm/ADT/DenseMap.h"
  20 #include "llvm/LTO/LTO.h"
  21 #include "llvm/Option/Arg.h"
  22 #include "llvm/Option/ArgList.h"
  23 #include "llvm/Option/Option.h"
  24 #include "llvm/Support/CommandLine.h"
  25 #include "llvm/Support/FileSystem.h"
  26 #include "llvm/Support/Path.h"
  27 #include "llvm/TextAPI/InterfaceFile.h"
  28 #include "llvm/TextAPI/TextAPIReader.h"
  29
  30 using namespace llvm;
  31 using namespace llvm::MachO;
  32 using namespace llvm::opt;
  33 using namespace llvm::sys;
  34 using namespace lld;
  35 using namespace lld::macho;
  36
  37 // Create prefix string literals used in Options.td
  38 #define PREFIX(NAME, VALUE) const char *NAME[] = VALUE;
  39 #include "Options.inc"
  40 #undef PREFIX
  41
  42 // Create table mapping all options defined in Options.td
  43 static const OptTable::Info optInfo[] = {
  44 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
  45   {X1, X2, X10,         X11,         OPT_##ID, Option::KIND##Class,            \
  46    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
  47 #include "Options.inc"
  48 #undef OPTION
  49 };
  50
  51 MachOOptTable::MachOOptTable() : OptTable(optInfo) {}
  52
  53 // Set color diagnostics according to --color-diagnostics={auto,always,never}
  54 // or --no-color-diagnostics flags.
  55 static void handleColorDiagnostics(InputArgList &args) {
  56   const Arg *arg =
  57       args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
  58                       OPT_no_color_diagnostics);
  59   if (!arg)
  60     return;
  61   if (arg->getOption().getID() == OPT_color_diagnostics) {
  62     lld::errs().enable_colors(true);
  63   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
  64     lld::errs().enable_colors(false);
  65   } else {
  66     StringRef s = arg->getValue();
  67     if (s == "always")
  68       lld::errs().enable_colors(true);
  69     else if (s == "never")
  70       lld::errs().enable_colors(false);
  71     else if (s != "auto")
  72       error("unknown option: --color-diagnostics=" + s);
  73   }
  74 }
  75
  76 InputArgList MachOOptTable::parse(ArrayRef<const char *> argv) {
  77   // Make InputArgList from string vectors.
  78   unsigned missingIndex;
  79   unsigned missingCount;
  80   SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
  81
  82   // Expand response files (arguments in the form of @<filename>)
  83   // and then parse the argument again.
  84   cl::ExpandResponseFiles(saver(), cl::TokenizeGNUCommandLine, vec);
  85   InputArgList args = ParseArgs(vec, missingIndex, missingCount);
  86
  87   // Handle -fatal_warnings early since it converts missing argument warnings
  88   // to errors.
  89   errorHandler().fatalWarnings = args.hasArg(OPT_fatal_warnings);
  90
  91   if (missingCount)
  92     error(Twine(args.getArgString(missingIndex)) + ": missing argument");
  93
  94   handleColorDiagnostics(args);
  95
  96   for (const Arg *arg : args.filtered(OPT_UNKNOWN)) {
  97     std::string nearest;
  98     if (findNearest(arg->getAsString(args), nearest) > 1)
  99       error("unknown argument '" + arg->getAsString(args) + "'");
 100     else
 101       error("unknown argument '" + arg->getAsString(args) +
 102             "', did you mean '" + nearest + "'");
 103   }
 104   return args;
 105 }
 106
 107 void MachOOptTable::printHelp(const char *argv0, bool showHidden) const {
 108   OptTable::printHelp(lld::outs(),
 109                       (std::string(argv0) + " [options] file...").c_str(),
 110                       "LLVM Linker", showHidden);
 111   lld::outs() << "\n";
 112 }
 113
 114 static std::string rewritePath(StringRef s) {
 115   if (fs::exists(s))
 116     return relativeToRoot(s);
 117   return std::string(s);
 118 }
 119
 120 static std::string rewriteInputPath(StringRef s) {
 121   // Don't bother rewriting "absolute" paths that are actually under the
 122   // syslibroot; simply rewriting the syslibroot is sufficient.
 123   if (rerootPath(s) == s && fs::exists(s))
 124     return relativeToRoot(s);
 125   return std::string(s);
 126 }
 127
 128 // Reconstructs command line arguments so that so that you can re-run
 129 // the same command with the same inputs. This is for --reproduce.
 130 std::string macho::createResponseFile(const InputArgList &args) {
 131   SmallString<0> data;
 132   raw_svector_ostream os(data);
 133
 134   // Copy the command line to the output while rewriting paths.
 135   for (const Arg *arg : args) {
 136     switch (arg->getOption().getID()) {
 137     case OPT_reproduce:
 138       break;
 139     case OPT_INPUT:
 140       os << quote(rewriteInputPath(arg->getValue())) << "\n";
 141       break;
 142     case OPT_o:
 143       os << "-o " << quote(path::filename(arg->getValue())) << "\n";
 144       break;
 145     case OPT_filelist:
 146       if (Optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
 147         for (StringRef path : args::getLines(*buffer))
 148           os << quote(rewriteInputPath(path)) << "\n";
 149       break;
 150     case OPT_force_load:
 151     case OPT_weak_library:
 152       os << arg->getSpelling() << " "
 153          << quote(rewriteInputPath(arg->getValue())) << "\n";
 154       break;
 155     case OPT_F:
 156     case OPT_L:
 157     case OPT_bundle_loader:
 158     case OPT_exported_symbols_list:
 159     case OPT_order_file:
 160     case OPT_rpath:
 161     case OPT_syslibroot:
 162     case OPT_unexported_symbols_list:
 163       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
 164          << "\n";
 165       break;
 166     case OPT_sectcreate:
 167       os << arg->getSpelling() << " " << quote(arg->getValue(0)) << " "
 168          << quote(arg->getValue(1)) << " "
 169          << quote(rewritePath(arg->getValue(2))) << "\n";
 170       break;
 171     default:
 172       os << toString(*arg) << "\n";
 173     }
 174   }
 175   return std::string(data.str());
 176 }
 177
 178 static void searchedDylib(const Twine &path, bool found) {
 179   if (config->printDylibSearch)
 180     message("searched " + path + (found ? ", found " : ", not found"));
 181   if (!found)
 182     depTracker->logFileNotFound(path);
 183 }
 184
 185 Optional<StringRef> macho::resolveDylibPath(StringRef dylibPath) {
 186   // TODO: if a tbd and dylib are both present, we should check to make sure
 187   // they are consistent.
 188   SmallString<261> tbdPath = dylibPath;
 189   path::replace_extension(tbdPath, ".tbd");
 190   bool tbdExists = fs::exists(tbdPath);
 191   searchedDylib(tbdPath, tbdExists);
 192   if (tbdExists)
 193     return saver().save(tbdPath.str());
 194
 195   bool dylibExists = fs::exists(dylibPath);
 196   searchedDylib(dylibPath, dylibExists);
 197   if (dylibExists)
 198     return saver().save(dylibPath);
 199   return {};
 200 }
 201
 202 // It's not uncommon to have multiple attempts to load a single dylib,
 203 // especially if it's a commonly re-exported core library.
 204 static DenseMap<CachedHashStringRef, DylibFile *> loadedDylibs;
 205
 206 DylibFile *macho::loadDylib(MemoryBufferRef mbref, DylibFile *umbrella,
 207                             bool isBundleLoader) {
 208   CachedHashStringRef path(mbref.getBufferIdentifier());
 209   DylibFile *&file = loadedDylibs[path];
 210   if (file)
 211     return file;
 212
 213   DylibFile *newFile;
 214   file_magic magic = identify_magic(mbref.getBuffer());
 215   if (magic == file_magic::tapi_file) {
 216     Expected<std::unique_ptr<InterfaceFile>> result = TextAPIReader::get(mbref);
 217     if (!result) {
 218       error("could not load TAPI file at " + mbref.getBufferIdentifier() +
 219             ": " + toString(result.takeError()));
 220       return nullptr;
 221     }
 222     file = make<DylibFile>(**result, umbrella, isBundleLoader);
 223
 224     // parseReexports() can recursively call loadDylib(). That's fine since
 225     // we wrote the DylibFile we just loaded to the loadDylib cache via the
 226     // `file` reference. But the recursive load can grow loadDylibs, so the
 227     // `file` reference might become invalid after parseReexports() -- so copy
 228     // the pointer it refers to before continuing.
 229     newFile = file;
 230     if (newFile->exportingFile)
 231       newFile->parseReexports(**result);
 232   } else {
 233     assert(magic == file_magic::macho_dynamically_linked_shared_lib ||
 234            magic == file_magic::macho_dynamically_linked_shared_lib_stub ||
 235            magic == file_magic::macho_executable ||
 236            magic == file_magic::macho_bundle);
 237     file = make<DylibFile>(mbref, umbrella, isBundleLoader);
 238
 239     // parseLoadCommands() can also recursively call loadDylib(). See comment
 240     // in previous block for why this means we must copy `file` here.
 241     newFile = file;
 242     if (newFile->exportingFile)
 243       newFile->parseLoadCommands(mbref);
 244   }
 245   return newFile;
 246 }
 247
 248 void macho::resetLoadedDylibs() { loadedDylibs.clear(); }
 249
 250 Optional<StringRef>
 251 macho::findPathCombination(const Twine &name,
 252                            const std::vector<StringRef> &roots,
 253                            ArrayRef<StringRef> extensions) {
 254   SmallString<261> base;
 255   for (StringRef dir : roots) {
 256     base = dir;
 257     path::append(base, name);
 258     for (StringRef ext : extensions) {
 259       Twine location = base + ext;
 260       bool exists = fs::exists(location);
 261       searchedDylib(location, exists);
 262       if (exists)
 263         return saver().save(location.str());
 264     }
 265   }
 266   return {};
 267 }
 268
 269 StringRef macho::rerootPath(StringRef path) {
 270   if (!path::is_absolute(path, path::Style::posix) || path.endswith(".o"))
 271     return path;
 272
 273   if (Optional<StringRef> rerootedPath =
 274           findPathCombination(path, config->systemLibraryRoots))
 275     return *rerootedPath;
 276
 277   return path;
 278 }
 279
 280 uint32_t macho::getModTime(StringRef path) {
 281   if (config->zeroModTime)
 282     return 0;
 283
 284   fs::file_status stat;
 285   if (!fs::status(path, stat))
 286     if (fs::exists(stat))
 287       return toTimeT(stat.getLastModificationTime());
 288
 289   warn("failed to get modification time of " + path);
 290   return 0;
 291 }
 292
 293 void macho::printArchiveMemberLoad(StringRef reason, const InputFile *f) {
 294   if (config->printEachFile)
 295     message(toString(f));
 296   if (config->printWhyLoad)
 297     message(reason + " forced load of " + toString(f));
 298 }
 299
 300 macho::DependencyTracker::DependencyTracker(StringRef path)
 301     : path(path), active(!path.empty()) {
 302   if (active && fs::exists(path) && !fs::can_write(path)) {
 303     warn("Ignoring dependency_info option since specified path is not "
 304          "writeable.");
 305     active = false;
 306   }
 307 }
 308
 309 void macho::DependencyTracker::write(StringRef version,
 310                                      const SetVector<InputFile *> &inputs,
 311                                      StringRef output) {
 312   if (!active)
 313     return;
 314
 315   std::error_code ec;
 316   raw_fd_ostream os(path, ec, fs::OF_None);
 317   if (ec) {
 318     warn("Error writing dependency info to file");
 319     return;
 320   }
 321
 322   auto addDep = [&os](DepOpCode opcode, const StringRef &path) {
 323     // XXX: Even though DepOpCode's underlying type is uint8_t,
 324     // this cast is still needed because Clang older than 10.x has a bug,
 325     // where it doesn't know to cast the enum to its underlying type.
 326     // Hence `<< DepOpCode` is ambiguous to it.
 327     os << static_cast<uint8_t>(opcode);
 328     os << path;
 329     os << '\0';
 330   };
 331
 332   addDep(DepOpCode::Version, version);
 333
 334   // Sort the input by its names.
 335   std::vector<StringRef> inputNames;
 336   inputNames.reserve(inputs.size());
 337   for (InputFile *f : inputs)
 338     inputNames.push_back(f->getName());
 339   llvm::sort(inputNames);
 340
 341   for (const StringRef &in : inputNames)
 342     addDep(DepOpCode::Input, in);
 343
 344   for (const std::string &f : notFounds)
 345     addDep(DepOpCode::NotFound, f);
 346
 347   addDep(DepOpCode::Output, output);
 348 }