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)                                                    \
  39   static constexpr StringLiteral NAME##_init[] = VALUE;                        \
  40   static constexpr ArrayRef<StringLiteral> NAME(NAME##_init,                   \
  41                                                 std::size(NAME##_init) - 1);
  42 #include "Options.inc"
  43 #undef PREFIX
  44
  45 // Create table mapping all options defined in Options.td
  46 static constexpr OptTable::Info optInfo[] = {
  47 #define OPTION(PREFIX, NAME, ID, KIND, GROUP, ALIAS, ALIASARGS, FLAGS,         \
  48                VISIBILITY, PARAM, HELPTEXT, METAVAR, VALUES)                   \
  49   {PREFIX,      NAME,        HELPTEXT,                                         \
  50    METAVAR,     OPT_##ID,    opt::Option::KIND##Class,                         \
  51    PARAM,       FLAGS,       VISIBILITY,                                       \
  52    OPT_##GROUP, OPT_##ALIAS, ALIASARGS,                                        \
  53    VALUES},
  54 #include "Options.inc"
  55 #undef OPTION
  56 };
  57
  58 MachOOptTable::MachOOptTable() : GenericOptTable(optInfo) {}
  59
  60 // Set color diagnostics according to --color-diagnostics={auto,always,never}
  61 // or --no-color-diagnostics flags.
  62 static void handleColorDiagnostics(InputArgList &args) {
  63   const Arg *arg =
  64       args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
  65                       OPT_no_color_diagnostics);
  66   if (!arg)
  67     return;
  68   if (arg->getOption().getID() == OPT_color_diagnostics) {
  69     lld::errs().enable_colors(true);
  70   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
  71     lld::errs().enable_colors(false);
  72   } else {
  73     StringRef s = arg->getValue();
  74     if (s == "always")
  75       lld::errs().enable_colors(true);
  76     else if (s == "never")
  77       lld::errs().enable_colors(false);
  78     else if (s != "auto")
  79       error("unknown option: --color-diagnostics=" + s);
  80   }
  81 }
  82
  83 InputArgList MachOOptTable::parse(ArrayRef<const char *> argv) {
  84   // Make InputArgList from string vectors.
  85   unsigned missingIndex;
  86   unsigned missingCount;
  87   SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
  88
  89   // Expand response files (arguments in the form of @<filename>)
  90   // and then parse the argument again.
  91   cl::ExpandResponseFiles(saver(), cl::TokenizeGNUCommandLine, vec);
  92   InputArgList args = ParseArgs(vec, missingIndex, missingCount);
  93
  94   // Handle -fatal_warnings early since it converts missing argument warnings
  95   // to errors.
  96   errorHandler().fatalWarnings = args.hasArg(OPT_fatal_warnings);
  97   errorHandler().suppressWarnings = args.hasArg(OPT_w);
  98
  99   if (missingCount)
 100     error(Twine(args.getArgString(missingIndex)) + ": missing argument");
 101
 102   handleColorDiagnostics(args);
 103
 104   for (const Arg *arg : args.filtered(OPT_UNKNOWN)) {
 105     std::string nearest;
 106     if (findNearest(arg->getAsString(args), nearest) > 1)
 107       error("unknown argument '" + arg->getAsString(args) + "'");
 108     else
 109       error("unknown argument '" + arg->getAsString(args) +
 110             "', did you mean '" + nearest + "'");
 111   }
 112   return args;
 113 }
 114
 115 void MachOOptTable::printHelp(const char *argv0, bool showHidden) const {
 116   OptTable::printHelp(lld::outs(),
 117                       (std::string(argv0) + " [options] file...").c_str(),
 118                       "LLVM Linker", showHidden);
 119   lld::outs() << "\n";
 120 }
 121
 122 static std::string rewritePath(StringRef s) {
 123   if (fs::exists(s))
 124     return relativeToRoot(s);
 125   return std::string(s);
 126 }
 127
 128 static std::string rewriteInputPath(StringRef s) {
 129   // Don't bother rewriting "absolute" paths that are actually under the
 130   // syslibroot; simply rewriting the syslibroot is sufficient.
 131   if (rerootPath(s) == s && fs::exists(s))
 132     return relativeToRoot(s);
 133   return std::string(s);
 134 }
 135
 136 // Reconstructs command line arguments so that so that you can re-run
 137 // the same command with the same inputs. This is for --reproduce.
 138 std::string macho::createResponseFile(const InputArgList &args) {
 139   SmallString<0> data;
 140   raw_svector_ostream os(data);
 141
 142   // Copy the command line to the output while rewriting paths.
 143   for (const Arg *arg : args) {
 144     switch (arg->getOption().getID()) {
 145     case OPT_reproduce:
 146       break;
 147     case OPT_INPUT:
 148       os << quote(rewriteInputPath(arg->getValue())) << "\n";
 149       break;
 150     case OPT_o:
 151       os << "-o " << quote(path::filename(arg->getValue())) << "\n";
 152       break;
 153     case OPT_filelist:
 154       if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
 155         for (StringRef path : args::getLines(*buffer))
 156           os << quote(rewriteInputPath(path)) << "\n";
 157       break;
 158     case OPT_force_load:
 159     case OPT_weak_library:
 160     case OPT_load_hidden:
 161       os << arg->getSpelling() << " "
 162          << quote(rewriteInputPath(arg->getValue())) << "\n";
 163       break;
 164     case OPT_F:
 165     case OPT_L:
 166     case OPT_bundle_loader:
 167     case OPT_exported_symbols_list:
 168     case OPT_order_file:
 169     case OPT_syslibroot:
 170     case OPT_unexported_symbols_list:
 171       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
 172          << "\n";
 173       break;
 174     case OPT_sectcreate:
 175       os << arg->getSpelling() << " " << quote(arg->getValue(0)) << " "
 176          << quote(arg->getValue(1)) << " "
 177          << quote(rewritePath(arg->getValue(2))) << "\n";
 178       break;
 179     default:
 180       os << toString(*arg) << "\n";
 181     }
 182   }
 183   return std::string(data.str());
 184 }
 185
 186 static void searchedDylib(const Twine &path, bool found) {
 187   if (config->printDylibSearch)
 188     message("searched " + path + (found ? ", found " : ", not found"));
 189   if (!found)
 190     depTracker->logFileNotFound(path);
 191 }
 192
 193 std::optional<StringRef> macho::resolveDylibPath(StringRef dylibPath) {
 194   // TODO: if a tbd and dylib are both present, we should check to make sure
 195   // they are consistent.
 196   SmallString<261> tbdPath = dylibPath;
 197   path::replace_extension(tbdPath, ".tbd");
 198   bool tbdExists = fs::exists(tbdPath);
 199   searchedDylib(tbdPath, tbdExists);
 200   if (tbdExists)
 201     return saver().save(tbdPath.str());
 202
 203   bool dylibExists = fs::exists(dylibPath);
 204   searchedDylib(dylibPath, dylibExists);
 205   if (dylibExists)
 206     return saver().save(dylibPath);
 207   return {};
 208 }
 209
 210 // It's not uncommon to have multiple attempts to load a single dylib,
 211 // especially if it's a commonly re-exported core library.
 212 static DenseMap<CachedHashStringRef, DylibFile *> loadedDylibs;
 213
 214 DylibFile *macho::loadDylib(MemoryBufferRef mbref, DylibFile *umbrella,
 215                             bool isBundleLoader, bool explicitlyLinked) {
 216   CachedHashStringRef path(mbref.getBufferIdentifier());
 217   DylibFile *&file = loadedDylibs[path];
 218   if (file) {
 219     if (explicitlyLinked)
 220       file->setExplicitlyLinked();
 221     return file;
 222   }
 223
 224   DylibFile *newFile;
 225   file_magic magic = identify_magic(mbref.getBuffer());
 226   if (magic == file_magic::tapi_file) {
 227     Expected<std::unique_ptr<InterfaceFile>> result = TextAPIReader::get(mbref);
 228     if (!result) {
 229       error("could not load TAPI file at " + mbref.getBufferIdentifier() +
 230             ": " + toString(result.takeError()));
 231       return nullptr;
 232     }
 233     file =
 234         make<DylibFile>(**result, umbrella, isBundleLoader, explicitlyLinked);
 235
 236     // parseReexports() can recursively call loadDylib(). That's fine since
 237     // we wrote the DylibFile we just loaded to the loadDylib cache via the
 238     // `file` reference. But the recursive load can grow loadDylibs, so the
 239     // `file` reference might become invalid after parseReexports() -- so copy
 240     // the pointer it refers to before continuing.
 241     newFile = file;
 242     if (newFile->exportingFile)
 243       newFile->parseReexports(**result);
 244   } else {
 245     assert(magic == file_magic::macho_dynamically_linked_shared_lib ||
 246            magic == file_magic::macho_dynamically_linked_shared_lib_stub ||
 247            magic == file_magic::macho_executable ||
 248            magic == file_magic::macho_bundle);
 249     file = make<DylibFile>(mbref, umbrella, isBundleLoader, explicitlyLinked);
 250
 251     // parseLoadCommands() can also recursively call loadDylib(). See comment
 252     // in previous block for why this means we must copy `file` here.
 253     newFile = file;
 254     if (newFile->exportingFile)
 255       newFile->parseLoadCommands(mbref);
 256   }
 257   return newFile;
 258 }
 259
 260 void macho::resetLoadedDylibs() { loadedDylibs.clear(); }
 261
 262 std::optional<StringRef>
 263 macho::findPathCombination(const Twine &name,
 264                            const std::vector<StringRef> &roots,
 265                            ArrayRef<StringRef> extensions) {
 266   SmallString<261> base;
 267   for (StringRef dir : roots) {
 268     base = dir;
 269     path::append(base, name);
 270     for (StringRef ext : extensions) {
 271       Twine location = base + ext;
 272       bool exists = fs::exists(location);
 273       searchedDylib(location, exists);
 274       if (exists)
 275         return saver().save(location.str());
 276     }
 277   }
 278   return {};
 279 }
 280
 281 StringRef macho::rerootPath(StringRef path) {
 282   if (!path::is_absolute(path, path::Style::posix) || path.ends_with(".o"))
 283     return path;
 284
 285   if (std::optional<StringRef> rerootedPath =
 286           findPathCombination(path, config->systemLibraryRoots))
 287     return *rerootedPath;
 288
 289   return path;
 290 }
 291
 292 uint32_t macho::getModTime(StringRef path) {
 293   if (config->zeroModTime)
 294     return 0;
 295
 296   fs::file_status stat;
 297   if (!fs::status(path, stat))
 298     if (fs::exists(stat))
 299       return toTimeT(stat.getLastModificationTime());
 300
 301   warn("failed to get modification time of " + path);
 302   return 0;
 303 }
 304
 305 void macho::printArchiveMemberLoad(StringRef reason, const InputFile *f) {
 306   if (config->printEachFile)
 307     message(toString(f));
 308   if (config->printWhyLoad)
 309     message(reason + " forced load of " + toString(f));
 310 }
 311
 312 macho::DependencyTracker::DependencyTracker(StringRef path)
 313     : path(path), active(!path.empty()) {
 314   if (active && fs::exists(path) && !fs::can_write(path)) {
 315     warn("Ignoring dependency_info option since specified path is not "
 316          "writeable.");
 317     active = false;
 318   }
 319 }
 320
 321 void macho::DependencyTracker::write(StringRef version,
 322                                      const SetVector<InputFile *> &inputs,
 323                                      StringRef output) {
 324   if (!active)
 325     return;
 326
 327   std::error_code ec;
 328   raw_fd_ostream os(path, ec, fs::OF_None);
 329   if (ec) {
 330     warn("Error writing dependency info to file");
 331     return;
 332   }
 333
 334   auto addDep = [&os](DepOpCode opcode, const StringRef &path) {
 335     // XXX: Even though DepOpCode's underlying type is uint8_t,
 336     // this cast is still needed because Clang older than 10.x has a bug,
 337     // where it doesn't know to cast the enum to its underlying type.
 338     // Hence `<< DepOpCode` is ambiguous to it.
 339     os << static_cast<uint8_t>(opcode);
 340     os << path;
 341     os << '\0';
 342   };
 343
 344   addDep(DepOpCode::Version, version);
 345
 346   // Sort the input by its names.
 347   std::vector<StringRef> inputNames;
 348   inputNames.reserve(inputs.size());
 349   for (InputFile *f : inputs)
 350     inputNames.push_back(f->getName());
 351   llvm::sort(inputNames);
 352
 353   for (const StringRef &in : inputNames)
 354     addDep(DepOpCode::Input, in);
 355
 356   for (const std::string &f : notFounds)
 357     addDep(DepOpCode::NotFound, f);
 358
 359   addDep(DepOpCode::Output, output);
 360 }