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, HELPTEXTSFORVARIANTS, METAVAR,     \
  49                VALUES)                                                         \
  50   {PREFIX,                                                                     \
  51    NAME,                                                                       \
  52    HELPTEXT,                                                                   \
  53    HELPTEXTSFORVARIANTS,                                                       \
  54    METAVAR,                                                                    \
  55    OPT_##ID,                                                                   \
  56    opt::Option::KIND##Class,                                                   \
  57    PARAM,                                                                      \
  58    FLAGS,                                                                      \
  59    VISIBILITY,                                                                 \
  60    OPT_##GROUP,                                                                \
  61    OPT_##ALIAS,                                                                \
  62    ALIASARGS,                                                                  \
  63    VALUES},
  64 #include "Options.inc"
  65 #undef OPTION
  66 };
  67
  68 MachOOptTable::MachOOptTable() : GenericOptTable(optInfo) {}
  69
  70 // Set color diagnostics according to --color-diagnostics={auto,always,never}
  71 // or --no-color-diagnostics flags.
  72 static void handleColorDiagnostics(InputArgList &args) {
  73   const Arg *arg =
  74       args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
  75                       OPT_no_color_diagnostics);
  76   if (!arg)
  77     return;
  78   if (arg->getOption().getID() == OPT_color_diagnostics) {
  79     lld::errs().enable_colors(true);
  80   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
  81     lld::errs().enable_colors(false);
  82   } else {
  83     StringRef s = arg->getValue();
  84     if (s == "always")
  85       lld::errs().enable_colors(true);
  86     else if (s == "never")
  87       lld::errs().enable_colors(false);
  88     else if (s != "auto")
  89       error("unknown option: --color-diagnostics=" + s);
  90   }
  91 }
  92
  93 InputArgList MachOOptTable::parse(ArrayRef<const char *> argv) {
  94   // Make InputArgList from string vectors.
  95   unsigned missingIndex;
  96   unsigned missingCount;
  97   SmallVector<const char *, 256> vec(argv.data(), argv.data() + argv.size());
  98
  99   // Expand response files (arguments in the form of @<filename>)
 100   // and then parse the argument again.
 101   cl::ExpandResponseFiles(saver(), cl::TokenizeGNUCommandLine, vec);
 102   InputArgList args = ParseArgs(vec, missingIndex, missingCount);
 103
 104   // Handle -fatal_warnings early since it converts missing argument warnings
 105   // to errors.
 106   errorHandler().fatalWarnings = args.hasArg(OPT_fatal_warnings);
 107   errorHandler().suppressWarnings = args.hasArg(OPT_w);
 108
 109   if (missingCount)
 110     error(Twine(args.getArgString(missingIndex)) + ": missing argument");
 111
 112   handleColorDiagnostics(args);
 113
 114   for (const Arg *arg : args.filtered(OPT_UNKNOWN)) {
 115     std::string nearest;
 116     if (findNearest(arg->getAsString(args), nearest) > 1)
 117       error("unknown argument '" + arg->getAsString(args) + "'");
 118     else
 119       error("unknown argument '" + arg->getAsString(args) +
 120             "', did you mean '" + nearest + "'");
 121   }
 122   return args;
 123 }
 124
 125 void MachOOptTable::printHelp(const char *argv0, bool showHidden) const {
 126   OptTable::printHelp(lld::outs(),
 127                       (std::string(argv0) + " [options] file...").c_str(),
 128                       "LLVM Linker", showHidden);
 129   lld::outs() << "\n";
 130 }
 131
 132 static std::string rewritePath(StringRef s) {
 133   if (fs::exists(s))
 134     return relativeToRoot(s);
 135   return std::string(s);
 136 }
 137
 138 static std::string rewriteInputPath(StringRef s) {
 139   // Don't bother rewriting "absolute" paths that are actually under the
 140   // syslibroot; simply rewriting the syslibroot is sufficient.
 141   if (rerootPath(s) == s && fs::exists(s))
 142     return relativeToRoot(s);
 143   return std::string(s);
 144 }
 145
 146 // Reconstructs command line arguments so that so that you can re-run
 147 // the same command with the same inputs. This is for --reproduce.
 148 std::string macho::createResponseFile(const InputArgList &args) {
 149   SmallString<0> data;
 150   raw_svector_ostream os(data);
 151
 152   // Copy the command line to the output while rewriting paths.
 153   for (const Arg *arg : args) {
 154     switch (arg->getOption().getID()) {
 155     case OPT_reproduce:
 156       break;
 157     case OPT_INPUT:
 158       os << quote(rewriteInputPath(arg->getValue())) << "\n";
 159       break;
 160     case OPT_o:
 161       os << "-o " << quote(path::filename(arg->getValue())) << "\n";
 162       break;
 163     case OPT_filelist:
 164       if (std::optional<MemoryBufferRef> buffer = readFile(arg->getValue()))
 165         for (StringRef path : args::getLines(*buffer))
 166           os << quote(rewriteInputPath(path)) << "\n";
 167       break;
 168     case OPT_force_load:
 169     case OPT_weak_library:
 170     case OPT_load_hidden:
 171       os << arg->getSpelling() << " "
 172          << quote(rewriteInputPath(arg->getValue())) << "\n";
 173       break;
 174     case OPT_F:
 175     case OPT_L:
 176     case OPT_bundle_loader:
 177     case OPT_exported_symbols_list:
 178     case OPT_order_file:
 179     case OPT_syslibroot:
 180     case OPT_unexported_symbols_list:
 181       os << arg->getSpelling() << " " << quote(rewritePath(arg->getValue()))
 182          << "\n";
 183       break;
 184     case OPT_sectcreate:
 185       os << arg->getSpelling() << " " << quote(arg->getValue(0)) << " "
 186          << quote(arg->getValue(1)) << " "
 187          << quote(rewritePath(arg->getValue(2))) << "\n";
 188       break;
 189     default:
 190       os << toString(*arg) << "\n";
 191     }
 192   }
 193   return std::string(data);
 194 }
 195
 196 static void searchedDylib(const Twine &path, bool found) {
 197   if (config->printDylibSearch)
 198     message("searched " + path + (found ? ", found " : ", not found"));
 199   if (!found)
 200     depTracker->logFileNotFound(path);
 201 }
 202
 203 std::optional<StringRef> macho::resolveDylibPath(StringRef dylibPath) {
 204   // TODO: if a tbd and dylib are both present, we should check to make sure
 205   // they are consistent.
 206   SmallString<261> tbdPath = dylibPath;
 207   path::replace_extension(tbdPath, ".tbd");
 208   bool tbdExists = fs::exists(tbdPath);
 209   searchedDylib(tbdPath, tbdExists);
 210   if (tbdExists)
 211     return saver().save(tbdPath.str());
 212
 213   bool dylibExists = fs::exists(dylibPath);
 214   searchedDylib(dylibPath, dylibExists);
 215   if (dylibExists)
 216     return saver().save(dylibPath);
 217   return {};
 218 }
 219
 220 // It's not uncommon to have multiple attempts to load a single dylib,
 221 // especially if it's a commonly re-exported core library.
 222 static DenseMap<CachedHashStringRef, DylibFile *> loadedDylibs;
 223
 224 DylibFile *macho::loadDylib(MemoryBufferRef mbref, DylibFile *umbrella,
 225                             bool isBundleLoader, bool explicitlyLinked) {
 226   CachedHashStringRef path(mbref.getBufferIdentifier());
 227   DylibFile *&file = loadedDylibs[path];
 228   if (file) {
 229     if (explicitlyLinked)
 230       file->setExplicitlyLinked();
 231     return file;
 232   }
 233
 234   DylibFile *newFile;
 235   file_magic magic = identify_magic(mbref.getBuffer());
 236   if (magic == file_magic::tapi_file) {
 237     Expected<std::unique_ptr<InterfaceFile>> result = TextAPIReader::get(mbref);
 238     if (!result) {
 239       error("could not load TAPI file at " + mbref.getBufferIdentifier() +
 240             ": " + toString(result.takeError()));
 241       return nullptr;
 242     }
 243     file =
 244         make<DylibFile>(**result, umbrella, isBundleLoader, explicitlyLinked);
 245
 246     // parseReexports() can recursively call loadDylib(). That's fine since
 247     // we wrote the DylibFile we just loaded to the loadDylib cache via the
 248     // `file` reference. But the recursive load can grow loadDylibs, so the
 249     // `file` reference might become invalid after parseReexports() -- so copy
 250     // the pointer it refers to before continuing.
 251     newFile = file;
 252     if (newFile->exportingFile)
 253       newFile->parseReexports(**result);
 254   } else {
 255     assert(magic == file_magic::macho_dynamically_linked_shared_lib ||
 256            magic == file_magic::macho_dynamically_linked_shared_lib_stub ||
 257            magic == file_magic::macho_executable ||
 258            magic == file_magic::macho_bundle);
 259     file = make<DylibFile>(mbref, umbrella, isBundleLoader, explicitlyLinked);
 260
 261     // parseLoadCommands() can also recursively call loadDylib(). See comment
 262     // in previous block for why this means we must copy `file` here.
 263     newFile = file;
 264     if (newFile->exportingFile)
 265       newFile->parseLoadCommands(mbref);
 266   }
 267   return newFile;
 268 }
 269
 270 void macho::resetLoadedDylibs() { loadedDylibs.clear(); }
 271
 272 std::optional<StringRef>
 273 macho::findPathCombination(const Twine &name,
 274                            const std::vector<StringRef> &roots,
 275                            ArrayRef<StringRef> extensions) {
 276   SmallString<261> base;
 277   for (StringRef dir : roots) {
 278     base = dir;
 279     path::append(base, name);
 280     for (StringRef ext : extensions) {
 281       Twine location = base + ext;
 282       bool exists = fs::exists(location);
 283       searchedDylib(location, exists);
 284       if (exists)
 285         return saver().save(location.str());
 286     }
 287   }
 288   return {};
 289 }
 290
 291 StringRef macho::rerootPath(StringRef path) {
 292   if (!path::is_absolute(path, path::Style::posix) || path.ends_with(".o"))
 293     return path;
 294
 295   if (std::optional<StringRef> rerootedPath =
 296           findPathCombination(path, config->systemLibraryRoots))
 297     return *rerootedPath;
 298
 299   return path;
 300 }
 301
 302 uint32_t macho::getModTime(StringRef path) {
 303   if (config->zeroModTime)
 304     return 0;
 305
 306   fs::file_status stat;
 307   if (!fs::status(path, stat))
 308     if (fs::exists(stat))
 309       return toTimeT(stat.getLastModificationTime());
 310
 311   warn("failed to get modification time of " + path);
 312   return 0;
 313 }
 314
 315 void macho::printArchiveMemberLoad(StringRef reason, const InputFile *f) {
 316   if (config->printEachFile)
 317     message(toString(f));
 318   if (config->printWhyLoad)
 319     message(reason + " forced load of " + toString(f));
 320 }
 321
 322 macho::DependencyTracker::DependencyTracker(StringRef path)
 323     : path(path), active(!path.empty()) {
 324   if (active && fs::exists(path) && !fs::can_write(path)) {
 325     warn("Ignoring dependency_info option since specified path is not "
 326          "writeable.");
 327     active = false;
 328   }
 329 }
 330
 331 void macho::DependencyTracker::write(StringRef version,
 332                                      const SetVector<InputFile *> &inputs,
 333                                      StringRef output) {
 334   if (!active)
 335     return;
 336
 337   std::error_code ec;
 338   raw_fd_ostream os(path, ec, fs::OF_None);
 339   if (ec) {
 340     warn("Error writing dependency info to file");
 341     return;
 342   }
 343
 344   auto addDep = [&os](DepOpCode opcode, const StringRef &path) {
 345     // XXX: Even though DepOpCode's underlying type is uint8_t,
 346     // this cast is still needed because Clang older than 10.x has a bug,
 347     // where it doesn't know to cast the enum to its underlying type.
 348     // Hence `<< DepOpCode` is ambiguous to it.
 349     os << static_cast<uint8_t>(opcode);
 350     os << path;
 351     os << '\0';
 352   };
 353
 354   addDep(DepOpCode::Version, version);
 355
 356   // Sort the input by its names.
 357   std::vector<StringRef> inputNames;
 358   inputNames.reserve(inputs.size());
 359   for (InputFile *f : inputs)
 360     inputNames.push_back(f->getName());
 361   llvm::sort(inputNames);
 362
 363   for (const StringRef &in : inputNames)
 364     addDep(DepOpCode::Input, in);
 365
 366   for (const std::string &f : notFounds)
 367     addDep(DepOpCode::NotFound, f);
 368
 369   addDep(DepOpCode::Output, output);
 370 }