lld/COFF/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 // This file contains utility functions for the driver. Because there
  10 // are so many small functions, we created this separate file to make
  11 // Driver.cpp less cluttered.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "COFFLinkerContext.h"
  16 #include "Driver.h"
  17 #include "Symbols.h"
  18 #include "lld/Common/ErrorHandler.h"
  19 #include "lld/Common/Memory.h"
  20 #include "llvm/ADT/STLExtras.h"
  21 #include "llvm/ADT/StringExtras.h"
  22 #include "llvm/ADT/StringSwitch.h"
  23 #include "llvm/BinaryFormat/COFF.h"
  24 #include "llvm/Object/COFF.h"
  25 #include "llvm/Object/WindowsResource.h"
  26 #include "llvm/Option/Arg.h"
  27 #include "llvm/Option/ArgList.h"
  28 #include "llvm/Option/Option.h"
  29 #include "llvm/Support/CommandLine.h"
  30 #include "llvm/Support/FileUtilities.h"
  31 #include "llvm/Support/MathExtras.h"
  32 #include "llvm/Support/Process.h"
  33 #include "llvm/Support/Program.h"
  34 #include "llvm/Support/raw_ostream.h"
  35 #include "llvm/WindowsManifest/WindowsManifestMerger.h"
  36 #include <limits>
  37 #include <memory>
  38 #include <optional>
  39
  40 using namespace llvm::COFF;
  41 using namespace llvm::opt;
  42 using namespace llvm;
  43 using llvm::sys::Process;
  44
  45 namespace lld {
  46 namespace coff {
  47 namespace {
  48
  49 const uint16_t SUBLANG_ENGLISH_US = 0x0409;
  50 const uint16_t RT_MANIFEST = 24;
  51
  52 class Executor {
  53 public:
  54   explicit Executor(StringRef s) : prog(saver().save(s)) {}
  55   void add(StringRef s) { args.push_back(saver().save(s)); }
  56   void add(std::string &s) { args.push_back(saver().save(s)); }
  57   void add(Twine s) { args.push_back(saver().save(s)); }
  58   void add(const char *s) { args.push_back(saver().save(s)); }
  59
  60   void run() {
  61     ErrorOr<std::string> exeOrErr = sys::findProgramByName(prog);
  62     if (auto ec = exeOrErr.getError())
  63       fatal("unable to find " + prog + " in PATH: " + ec.message());
  64     StringRef exe = saver().save(*exeOrErr);
  65     args.insert(args.begin(), exe);
  66
  67     if (sys::ExecuteAndWait(args[0], args) != 0)
  68       fatal("ExecuteAndWait failed: " +
  69             llvm::join(args.begin(), args.end(), " "));
  70   }
  71
  72 private:
  73   StringRef prog;
  74   std::vector<StringRef> args;
  75 };
  76
  77 } // anonymous namespace
  78
  79 // Parses a string in the form of "<integer>[,<integer>]".
  80 void LinkerDriver::parseNumbers(StringRef arg, uint64_t *addr, uint64_t *size) {
  81   auto [s1, s2] = arg.split(',');
  82   if (s1.getAsInteger(0, *addr))
  83     fatal("invalid number: " + s1);
  84   if (size && !s2.empty() && s2.getAsInteger(0, *size))
  85     fatal("invalid number: " + s2);
  86 }
  87
  88 // Parses a string in the form of "<integer>[.<integer>]".
  89 // If second number is not present, Minor is set to 0.
  90 void LinkerDriver::parseVersion(StringRef arg, uint32_t *major,
  91                                 uint32_t *minor) {
  92   auto [s1, s2] = arg.split('.');
  93   if (s1.getAsInteger(10, *major))
  94     fatal("invalid number: " + s1);
  95   *minor = 0;
  96   if (!s2.empty() && s2.getAsInteger(10, *minor))
  97     fatal("invalid number: " + s2);
  98 }
  99
 100 void LinkerDriver::parseGuard(StringRef fullArg) {
 101   SmallVector<StringRef, 1> splitArgs;
 102   fullArg.split(splitArgs, ",");
 103   for (StringRef arg : splitArgs) {
 104     if (arg.equals_insensitive("no"))
 105       ctx.config.guardCF = GuardCFLevel::Off;
 106     else if (arg.equals_insensitive("nolongjmp"))
 107       ctx.config.guardCF &= ~GuardCFLevel::LongJmp;
 108     else if (arg.equals_insensitive("noehcont"))
 109       ctx.config.guardCF &= ~GuardCFLevel::EHCont;
 110     else if (arg.equals_insensitive("cf") || arg.equals_insensitive("longjmp"))
 111       ctx.config.guardCF |= GuardCFLevel::CF | GuardCFLevel::LongJmp;
 112     else if (arg.equals_insensitive("ehcont"))
 113       ctx.config.guardCF |= GuardCFLevel::CF | GuardCFLevel::EHCont;
 114     else
 115       fatal("invalid argument to /guard: " + arg);
 116   }
 117 }
 118
 119 // Parses a string in the form of "<subsystem>[,<integer>[.<integer>]]".
 120 void LinkerDriver::parseSubsystem(StringRef arg, WindowsSubsystem *sys,
 121                                   uint32_t *major, uint32_t *minor,
 122                                   bool *gotVersion) {
 123   auto [sysStr, ver] = arg.split(',');
 124   std::string sysStrLower = sysStr.lower();
 125   *sys = StringSwitch<WindowsSubsystem>(sysStrLower)
 126     .Case("boot_application", IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION)
 127     .Case("console", IMAGE_SUBSYSTEM_WINDOWS_CUI)
 128     .Case("default", IMAGE_SUBSYSTEM_UNKNOWN)
 129     .Case("efi_application", IMAGE_SUBSYSTEM_EFI_APPLICATION)
 130     .Case("efi_boot_service_driver", IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER)
 131     .Case("efi_rom", IMAGE_SUBSYSTEM_EFI_ROM)
 132     .Case("efi_runtime_driver", IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER)
 133     .Case("native", IMAGE_SUBSYSTEM_NATIVE)
 134     .Case("posix", IMAGE_SUBSYSTEM_POSIX_CUI)
 135     .Case("windows", IMAGE_SUBSYSTEM_WINDOWS_GUI)
 136     .Default(IMAGE_SUBSYSTEM_UNKNOWN);
 137   if (*sys == IMAGE_SUBSYSTEM_UNKNOWN && sysStrLower != "default")
 138     fatal("unknown subsystem: " + sysStr);
 139   if (!ver.empty())
 140     parseVersion(ver, major, minor);
 141   if (gotVersion)
 142     *gotVersion = !ver.empty();
 143 }
 144
 145 // Parse a string of the form of "<from>=<to>".
 146 // Results are directly written to Config.
 147 void LinkerDriver::parseAlternateName(StringRef s) {
 148   auto [from, to] = s.split('=');
 149   if (from.empty() || to.empty())
 150     fatal("/alternatename: invalid argument: " + s);
 151   auto it = ctx.config.alternateNames.find(from);
 152   if (it != ctx.config.alternateNames.end() && it->second != to)
 153     fatal("/alternatename: conflicts: " + s);
 154   ctx.config.alternateNames.insert(it, std::make_pair(from, to));
 155 }
 156
 157 // Parse a string of the form of "<from>=<to>".
 158 // Results are directly written to Config.
 159 void LinkerDriver::parseMerge(StringRef s) {
 160   auto [from, to] = s.split('=');
 161   if (from.empty() || to.empty())
 162     fatal("/merge: invalid argument: " + s);
 163   if (from == ".rsrc" || to == ".rsrc")
 164     fatal("/merge: cannot merge '.rsrc' with any section");
 165   if (from == ".reloc" || to == ".reloc")
 166     fatal("/merge: cannot merge '.reloc' with any section");
 167   auto pair = ctx.config.merge.insert(std::make_pair(from, to));
 168   bool inserted = pair.second;
 169   if (!inserted) {
 170     StringRef existing = pair.first->second;
 171     if (existing != to)
 172       warn(s + ": already merged into " + existing);
 173   }
 174 }
 175
 176 void LinkerDriver::parsePDBPageSize(StringRef s) {
 177   int v;
 178   if (s.getAsInteger(0, v)) {
 179     error("/pdbpagesize: invalid argument: " + s);
 180     return;
 181   }
 182   if (v != 4096 && v != 8192 && v != 16384 && v != 32768) {
 183     error("/pdbpagesize: invalid argument: " + s);
 184     return;
 185   }
 186
 187   ctx.config.pdbPageSize = v;
 188 }
 189
 190 static uint32_t parseSectionAttributes(StringRef s) {
 191   uint32_t ret = 0;
 192   for (char c : s.lower()) {
 193     switch (c) {
 194     case 'd':
 195       ret |= IMAGE_SCN_MEM_DISCARDABLE;
 196       break;
 197     case 'e':
 198       ret |= IMAGE_SCN_MEM_EXECUTE;
 199       break;
 200     case 'k':
 201       ret |= IMAGE_SCN_MEM_NOT_CACHED;
 202       break;
 203     case 'p':
 204       ret |= IMAGE_SCN_MEM_NOT_PAGED;
 205       break;
 206     case 'r':
 207       ret |= IMAGE_SCN_MEM_READ;
 208       break;
 209     case 's':
 210       ret |= IMAGE_SCN_MEM_SHARED;
 211       break;
 212     case 'w':
 213       ret |= IMAGE_SCN_MEM_WRITE;
 214       break;
 215     default:
 216       fatal("/section: invalid argument: " + s);
 217     }
 218   }
 219   return ret;
 220 }
 221
 222 // Parses /section option argument.
 223 void LinkerDriver::parseSection(StringRef s) {
 224   auto [name, attrs] = s.split(',');
 225   if (name.empty() || attrs.empty())
 226     fatal("/section: invalid argument: " + s);
 227   ctx.config.section[name] = parseSectionAttributes(attrs);
 228 }
 229
 230 // Parses /aligncomm option argument.
 231 void LinkerDriver::parseAligncomm(StringRef s) {
 232   auto [name, align] = s.split(',');
 233   if (name.empty() || align.empty()) {
 234     error("/aligncomm: invalid argument: " + s);
 235     return;
 236   }
 237   int v;
 238   if (align.getAsInteger(0, v)) {
 239     error("/aligncomm: invalid argument: " + s);
 240     return;
 241   }
 242   ctx.config.alignComm[std::string(name)] =
 243       std::max(ctx.config.alignComm[std::string(name)], 1 << v);
 244 }
 245
 246 // Parses /functionpadmin option argument.
 247 void LinkerDriver::parseFunctionPadMin(llvm::opt::Arg *a) {
 248   StringRef arg = a->getNumValues() ? a->getValue() : "";
 249   if (!arg.empty()) {
 250     // Optional padding in bytes is given.
 251     if (arg.getAsInteger(0, ctx.config.functionPadMin))
 252       error("/functionpadmin: invalid argument: " + arg);
 253     return;
 254   }
 255   // No optional argument given.
 256   // Set default padding based on machine, similar to link.exe.
 257   // There is no default padding for ARM platforms.
 258   if (ctx.config.machine == I386) {
 259     ctx.config.functionPadMin = 5;
 260   } else if (ctx.config.machine == AMD64) {
 261     ctx.config.functionPadMin = 6;
 262   } else {
 263     error("/functionpadmin: invalid argument for this machine: " + arg);
 264   }
 265 }
 266
 267 // Parses a string in the form of "EMBED[,=<integer>]|NO".
 268 // Results are directly written to
 269 // Config.
 270 void LinkerDriver::parseManifest(StringRef arg) {
 271   if (arg.equals_insensitive("no")) {
 272     ctx.config.manifest = Configuration::No;
 273     return;
 274   }
 275   if (!arg.starts_with_insensitive("embed"))
 276     fatal("invalid option " + arg);
 277   ctx.config.manifest = Configuration::Embed;
 278   arg = arg.substr(strlen("embed"));
 279   if (arg.empty())
 280     return;
 281   if (!arg.starts_with_insensitive(",id="))
 282     fatal("invalid option " + arg);
 283   arg = arg.substr(strlen(",id="));
 284   if (arg.getAsInteger(0, ctx.config.manifestID))
 285     fatal("invalid option " + arg);
 286 }
 287
 288 // Parses a string in the form of "level=<string>|uiAccess=<string>|NO".
 289 // Results are directly written to Config.
 290 void LinkerDriver::parseManifestUAC(StringRef arg) {
 291   if (arg.equals_insensitive("no")) {
 292     ctx.config.manifestUAC = false;
 293     return;
 294   }
 295   for (;;) {
 296     arg = arg.ltrim();
 297     if (arg.empty())
 298       return;
 299     if (arg.starts_with_insensitive("level=")) {
 300       arg = arg.substr(strlen("level="));
 301       std::tie(ctx.config.manifestLevel, arg) = arg.split(" ");
 302       continue;
 303     }
 304     if (arg.starts_with_insensitive("uiaccess=")) {
 305       arg = arg.substr(strlen("uiaccess="));
 306       std::tie(ctx.config.manifestUIAccess, arg) = arg.split(" ");
 307       continue;
 308     }
 309     fatal("invalid option " + arg);
 310   }
 311 }
 312
 313 // Parses a string in the form of "cd|net[,(cd|net)]*"
 314 // Results are directly written to Config.
 315 void LinkerDriver::parseSwaprun(StringRef arg) {
 316   do {
 317     auto [swaprun, newArg] = arg.split(',');
 318     if (swaprun.equals_insensitive("cd"))
 319       ctx.config.swaprunCD = true;
 320     else if (swaprun.equals_insensitive("net"))
 321       ctx.config.swaprunNet = true;
 322     else if (swaprun.empty())
 323       error("/swaprun: missing argument");
 324     else
 325       error("/swaprun: invalid argument: " + swaprun);
 326     // To catch trailing commas, e.g. `/spawrun:cd,`
 327     if (newArg.empty() && arg.ends_with(","))
 328       error("/swaprun: missing argument");
 329     arg = newArg;
 330   } while (!arg.empty());
 331 }
 332
 333 // An RAII temporary file class that automatically removes a temporary file.
 334 namespace {
 335 class TemporaryFile {
 336 public:
 337   TemporaryFile(StringRef prefix, StringRef extn, StringRef contents = "") {
 338     SmallString<128> s;
 339     if (auto ec = sys::fs::createTemporaryFile("lld-" + prefix, extn, s))
 340       fatal("cannot create a temporary file: " + ec.message());
 341     path = std::string(s.str());
 342
 343     if (!contents.empty()) {
 344       std::error_code ec;
 345       raw_fd_ostream os(path, ec, sys::fs::OF_None);
 346       if (ec)
 347         fatal("failed to open " + path + ": " + ec.message());
 348       os << contents;
 349     }
 350   }
 351
 352   TemporaryFile(TemporaryFile &&obj) noexcept { std::swap(path, obj.path); }
 353
 354   ~TemporaryFile() {
 355     if (path.empty())
 356       return;
 357     if (sys::fs::remove(path))
 358       fatal("failed to remove " + path);
 359   }
 360
 361   // Returns a memory buffer of this temporary file.
 362   // Note that this function does not leave the file open,
 363   // so it is safe to remove the file immediately after this function
 364   // is called (you cannot remove an opened file on Windows.)
 365   std::unique_ptr<MemoryBuffer> getMemoryBuffer() {
 366     // IsVolatile=true forces MemoryBuffer to not use mmap().
 367     return CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
 368                                        /*RequiresNullTerminator=*/false,
 369                                        /*IsVolatile=*/true),
 370                  "could not open " + path);
 371   }
 372
 373   std::string path;
 374 };
 375 }
 376
 377 std::string LinkerDriver::createDefaultXml() {
 378   std::string ret;
 379   raw_string_ostream os(ret);
 380
 381   // Emit the XML. Note that we do *not* verify that the XML attributes are
 382   // syntactically correct. This is intentional for link.exe compatibility.
 383   os << "<?xml version=\"1.0\" standalone=\"yes\"?>\n"
 384      << "<assembly xmlns=\"urn:schemas-microsoft-com:asm.v1\"\n"
 385      << "          manifestVersion=\"1.0\">\n";
 386   if (ctx.config.manifestUAC) {
 387     os << "  <trustInfo>\n"
 388        << "    <security>\n"
 389        << "      <requestedPrivileges>\n"
 390        << "         <requestedExecutionLevel level=" << ctx.config.manifestLevel
 391        << " uiAccess=" << ctx.config.manifestUIAccess << "/>\n"
 392        << "      </requestedPrivileges>\n"
 393        << "    </security>\n"
 394        << "  </trustInfo>\n";
 395   }
 396   for (auto manifestDependency : ctx.config.manifestDependencies) {
 397     os << "  <dependency>\n"
 398        << "    <dependentAssembly>\n"
 399        << "      <assemblyIdentity " << manifestDependency << " />\n"
 400        << "    </dependentAssembly>\n"
 401        << "  </dependency>\n";
 402   }
 403   os << "</assembly>\n";
 404   return os.str();
 405 }
 406
 407 std::string
 408 LinkerDriver::createManifestXmlWithInternalMt(StringRef defaultXml) {
 409   std::unique_ptr<MemoryBuffer> defaultXmlCopy =
 410       MemoryBuffer::getMemBufferCopy(defaultXml);
 411
 412   windows_manifest::WindowsManifestMerger merger;
 413   if (auto e = merger.merge(*defaultXmlCopy.get()))
 414     fatal("internal manifest tool failed on default xml: " +
 415           toString(std::move(e)));
 416
 417   for (StringRef filename : ctx.config.manifestInput) {
 418     std::unique_ptr<MemoryBuffer> manifest =
 419         check(MemoryBuffer::getFile(filename));
 420     // Call takeBuffer to include in /reproduce: output if applicable.
 421     if (auto e = merger.merge(takeBuffer(std::move(manifest))))
 422       fatal("internal manifest tool failed on file " + filename + ": " +
 423             toString(std::move(e)));
 424   }
 425
 426   return std::string(merger.getMergedManifest().get()->getBuffer());
 427 }
 428
 429 std::string
 430 LinkerDriver::createManifestXmlWithExternalMt(StringRef defaultXml) {
 431   // Create the default manifest file as a temporary file.
 432   TemporaryFile Default("defaultxml", "manifest");
 433   std::error_code ec;
 434   raw_fd_ostream os(Default.path, ec, sys::fs::OF_TextWithCRLF);
 435   if (ec)
 436     fatal("failed to open " + Default.path + ": " + ec.message());
 437   os << defaultXml;
 438   os.close();
 439
 440   // Merge user-supplied manifests if they are given.  Since libxml2 is not
 441   // enabled, we must shell out to Microsoft's mt.exe tool.
 442   TemporaryFile user("user", "manifest");
 443
 444   Executor e("mt.exe");
 445   e.add("/manifest");
 446   e.add(Default.path);
 447   for (StringRef filename : ctx.config.manifestInput) {
 448     e.add("/manifest");
 449     e.add(filename);
 450
 451     // Manually add the file to the /reproduce: tar if needed.
 452     if (tar)
 453       if (auto mbOrErr = MemoryBuffer::getFile(filename))
 454         takeBuffer(std::move(*mbOrErr));
 455   }
 456   e.add("/nologo");
 457   e.add("/out:" + StringRef(user.path));
 458   e.run();
 459
 460   return std::string(
 461       CHECK(MemoryBuffer::getFile(user.path), "could not open " + user.path)
 462           .get()
 463           ->getBuffer());
 464 }
 465
 466 std::string LinkerDriver::createManifestXml() {
 467   std::string defaultXml = createDefaultXml();
 468   if (ctx.config.manifestInput.empty())
 469     return defaultXml;
 470
 471   if (windows_manifest::isAvailable())
 472     return createManifestXmlWithInternalMt(defaultXml);
 473
 474   return createManifestXmlWithExternalMt(defaultXml);
 475 }
 476
 477 std::unique_ptr<WritableMemoryBuffer>
 478 LinkerDriver::createMemoryBufferForManifestRes(size_t manifestSize) {
 479   size_t resSize = alignTo(
 480       object::WIN_RES_MAGIC_SIZE + object::WIN_RES_NULL_ENTRY_SIZE +
 481           sizeof(object::WinResHeaderPrefix) + sizeof(object::WinResIDs) +
 482           sizeof(object::WinResHeaderSuffix) + manifestSize,
 483       object::WIN_RES_DATA_ALIGNMENT);
 484   return WritableMemoryBuffer::getNewMemBuffer(resSize, ctx.config.outputFile +
 485                                                             ".manifest.res");
 486 }
 487
 488 static void writeResFileHeader(char *&buf) {
 489   memcpy(buf, COFF::WinResMagic, sizeof(COFF::WinResMagic));
 490   buf += sizeof(COFF::WinResMagic);
 491   memset(buf, 0, object::WIN_RES_NULL_ENTRY_SIZE);
 492   buf += object::WIN_RES_NULL_ENTRY_SIZE;
 493 }
 494
 495 static void writeResEntryHeader(char *&buf, size_t manifestSize,
 496                                 int manifestID) {
 497   // Write the prefix.
 498   auto *prefix = reinterpret_cast<object::WinResHeaderPrefix *>(buf);
 499   prefix->DataSize = manifestSize;
 500   prefix->HeaderSize = sizeof(object::WinResHeaderPrefix) +
 501                        sizeof(object::WinResIDs) +
 502                        sizeof(object::WinResHeaderSuffix);
 503   buf += sizeof(object::WinResHeaderPrefix);
 504
 505   // Write the Type/Name IDs.
 506   auto *iDs = reinterpret_cast<object::WinResIDs *>(buf);
 507   iDs->setType(RT_MANIFEST);
 508   iDs->setName(manifestID);
 509   buf += sizeof(object::WinResIDs);
 510
 511   // Write the suffix.
 512   auto *suffix = reinterpret_cast<object::WinResHeaderSuffix *>(buf);
 513   suffix->DataVersion = 0;
 514   suffix->MemoryFlags = object::WIN_RES_PURE_MOVEABLE;
 515   suffix->Language = SUBLANG_ENGLISH_US;
 516   suffix->Version = 0;
 517   suffix->Characteristics = 0;
 518   buf += sizeof(object::WinResHeaderSuffix);
 519 }
 520
 521 // Create a resource file containing a manifest XML.
 522 std::unique_ptr<MemoryBuffer> LinkerDriver::createManifestRes() {
 523   std::string manifest = createManifestXml();
 524
 525   std::unique_ptr<WritableMemoryBuffer> res =
 526       createMemoryBufferForManifestRes(manifest.size());
 527
 528   char *buf = res->getBufferStart();
 529   writeResFileHeader(buf);
 530   writeResEntryHeader(buf, manifest.size(), ctx.config.manifestID);
 531
 532   // Copy the manifest data into the .res file.
 533   std::copy(manifest.begin(), manifest.end(), buf);
 534   return std::move(res);
 535 }
 536
 537 void LinkerDriver::createSideBySideManifest() {
 538   std::string path = std::string(ctx.config.manifestFile);
 539   if (path == "")
 540     path = ctx.config.outputFile + ".manifest";
 541   std::error_code ec;
 542   raw_fd_ostream out(path, ec, sys::fs::OF_TextWithCRLF);
 543   if (ec)
 544     fatal("failed to create manifest: " + ec.message());
 545   out << createManifestXml();
 546 }
 547
 548 // Parse a string in the form of
 549 // "<name>[=<internalname>][,@ordinal[,NONAME]][,DATA][,PRIVATE]"
 550 // or "<name>=<dllname>.<name>".
 551 // Used for parsing /export arguments.
 552 Export LinkerDriver::parseExport(StringRef arg) {
 553   Export e;
 554   e.source = ExportSource::Export;
 555
 556   StringRef rest;
 557   std::tie(e.name, rest) = arg.split(",");
 558   if (e.name.empty())
 559     goto err;
 560
 561   if (e.name.contains('=')) {
 562     auto [x, y] = e.name.split("=");
 563
 564     // If "<name>=<dllname>.<name>".
 565     if (y.contains(".")) {
 566       e.name = x;
 567       e.forwardTo = y;
 568       return e;
 569     }
 570
 571     e.extName = x;
 572     e.name = y;
 573     if (e.name.empty())
 574       goto err;
 575   }
 576
 577   // If "<name>=<internalname>[,@ordinal[,NONAME]][,DATA][,PRIVATE]"
 578   while (!rest.empty()) {
 579     StringRef tok;
 580     std::tie(tok, rest) = rest.split(",");
 581     if (tok.equals_insensitive("noname")) {
 582       if (e.ordinal == 0)
 583         goto err;
 584       e.noname = true;
 585       continue;
 586     }
 587     if (tok.equals_insensitive("data")) {
 588       e.data = true;
 589       continue;
 590     }
 591     if (tok.equals_insensitive("constant")) {
 592       e.constant = true;
 593       continue;
 594     }
 595     if (tok.equals_insensitive("private")) {
 596       e.isPrivate = true;
 597       continue;
 598     }
 599     if (tok.starts_with("@")) {
 600       int32_t ord;
 601       if (tok.substr(1).getAsInteger(0, ord))
 602         goto err;
 603       if (ord <= 0 || 65535 < ord)
 604         goto err;
 605       e.ordinal = ord;
 606       continue;
 607     }
 608     goto err;
 609   }
 610   return e;
 611
 612 err:
 613   fatal("invalid /export: " + arg);
 614 }
 615
 616 static StringRef undecorate(COFFLinkerContext &ctx, StringRef sym) {
 617   if (ctx.config.machine != I386)
 618     return sym;
 619   // In MSVC mode, a fully decorated stdcall function is exported
 620   // as-is with the leading underscore (with type IMPORT_NAME).
 621   // In MinGW mode, a decorated stdcall function gets the underscore
 622   // removed, just like normal cdecl functions.
 623   if (sym.starts_with("_") && sym.contains('@') && !ctx.config.mingw)
 624     return sym;
 625   return sym.starts_with("_") ? sym.substr(1) : sym;
 626 }
 627
 628 // Convert stdcall/fastcall style symbols into unsuffixed symbols,
 629 // with or without a leading underscore. (MinGW specific.)
 630 static StringRef killAt(StringRef sym, bool prefix) {
 631   if (sym.empty())
 632     return sym;
 633   // Strip any trailing stdcall suffix
 634   sym = sym.substr(0, sym.find('@', 1));
 635   if (!sym.starts_with("@")) {
 636     if (prefix && !sym.starts_with("_"))
 637       return saver().save("_" + sym);
 638     return sym;
 639   }
 640   // For fastcall, remove the leading @ and replace it with an
 641   // underscore, if prefixes are used.
 642   sym = sym.substr(1);
 643   if (prefix)
 644     sym = saver().save("_" + sym);
 645   return sym;
 646 }
 647
 648 static StringRef exportSourceName(ExportSource s) {
 649   switch (s) {
 650   case ExportSource::Directives:
 651     return "source file (directives)";
 652   case ExportSource::Export:
 653     return "/export";
 654   case ExportSource::ModuleDefinition:
 655     return "/def";
 656   default:
 657     llvm_unreachable("unknown ExportSource");
 658   }
 659 }
 660
 661 // Performs error checking on all /export arguments.
 662 // It also sets ordinals.
 663 void LinkerDriver::fixupExports() {
 664   // Symbol ordinals must be unique.
 665   std::set<uint16_t> ords;
 666   for (Export &e : ctx.config.exports) {
 667     if (e.ordinal == 0)
 668       continue;
 669     if (!ords.insert(e.ordinal).second)
 670       fatal("duplicate export ordinal: " + e.name);
 671   }
 672
 673   for (Export &e : ctx.config.exports) {
 674     if (!e.forwardTo.empty()) {
 675       e.exportName = undecorate(ctx, e.name);
 676     } else {
 677       e.exportName = undecorate(ctx, e.extName.empty() ? e.name : e.extName);
 678     }
 679   }
 680
 681   if (ctx.config.killAt && ctx.config.machine == I386) {
 682     for (Export &e : ctx.config.exports) {
 683       e.name = killAt(e.name, true);
 684       e.exportName = killAt(e.exportName, false);
 685       e.extName = killAt(e.extName, true);
 686       e.symbolName = killAt(e.symbolName, true);
 687     }
 688   }
 689
 690   // Uniquefy by name.
 691   DenseMap<StringRef, std::pair<Export *, unsigned>> map(
 692       ctx.config.exports.size());
 693   std::vector<Export> v;
 694   for (Export &e : ctx.config.exports) {
 695     auto pair = map.insert(std::make_pair(e.exportName, std::make_pair(&e, 0)));
 696     bool inserted = pair.second;
 697     if (inserted) {
 698       pair.first->second.second = v.size();
 699       v.push_back(e);
 700       continue;
 701     }
 702     Export *existing = pair.first->second.first;
 703     if (e == *existing || e.name != existing->name)
 704       continue;
 705     // If the existing export comes from .OBJ directives, we are allowed to
 706     // overwrite it with /DEF: or /EXPORT without any warning, as MSVC link.exe
 707     // does.
 708     if (existing->source == ExportSource::Directives) {
 709       *existing = e;
 710       v[pair.first->second.second] = e;
 711       continue;
 712     }
 713     if (existing->source == e.source) {
 714       warn(Twine("duplicate ") + exportSourceName(existing->source) +
 715            " option: " + e.name);
 716     } else {
 717       warn("duplicate export: " + e.name +
 718            Twine(" first seen in " + exportSourceName(existing->source) +
 719                  Twine(", now in " + exportSourceName(e.source))));
 720     }
 721   }
 722   ctx.config.exports = std::move(v);
 723
 724   // Sort by name.
 725   llvm::sort(ctx.config.exports, [](const Export &a, const Export &b) {
 726     return a.exportName < b.exportName;
 727   });
 728 }
 729
 730 void LinkerDriver::assignExportOrdinals() {
 731   // Assign unique ordinals if default (= 0).
 732   uint32_t max = 0;
 733   for (Export &e : ctx.config.exports)
 734     max = std::max(max, (uint32_t)e.ordinal);
 735   for (Export &e : ctx.config.exports)
 736     if (e.ordinal == 0)
 737       e.ordinal = ++max;
 738   if (max > std::numeric_limits<uint16_t>::max())
 739     fatal("too many exported symbols (got " + Twine(max) + ", max " +
 740           Twine(std::numeric_limits<uint16_t>::max()) + ")");
 741 }
 742
 743 // Parses a string in the form of "key=value" and check
 744 // if value matches previous values for the same key.
 745 void LinkerDriver::checkFailIfMismatch(StringRef arg, InputFile *source) {
 746   auto [k, v] = arg.split('=');
 747   if (k.empty() || v.empty())
 748     fatal("/failifmismatch: invalid argument: " + arg);
 749   std::pair<StringRef, InputFile *> existing = ctx.config.mustMatch[k];
 750   if (!existing.first.empty() && v != existing.first) {
 751     std::string sourceStr = source ? toString(source) : "cmd-line";
 752     std::string existingStr =
 753         existing.second ? toString(existing.second) : "cmd-line";
 754     fatal("/failifmismatch: mismatch detected for '" + k + "':\n>>> " +
 755           existingStr + " has value " + existing.first + "\n>>> " + sourceStr +
 756           " has value " + v);
 757   }
 758   ctx.config.mustMatch[k] = {v, source};
 759 }
 760
 761 // Convert Windows resource files (.res files) to a .obj file.
 762 // Does what cvtres.exe does, but in-process and cross-platform.
 763 MemoryBufferRef LinkerDriver::convertResToCOFF(ArrayRef<MemoryBufferRef> mbs,
 764                                                ArrayRef<ObjFile *> objs) {
 765   object::WindowsResourceParser parser(/* MinGW */ ctx.config.mingw);
 766
 767   std::vector<std::string> duplicates;
 768   for (MemoryBufferRef mb : mbs) {
 769     std::unique_ptr<object::Binary> bin = check(object::createBinary(mb));
 770     object::WindowsResource *rf = dyn_cast<object::WindowsResource>(bin.get());
 771     if (!rf)
 772       fatal("cannot compile non-resource file as resource");
 773
 774     if (auto ec = parser.parse(rf, duplicates))
 775       fatal(toString(std::move(ec)));
 776   }
 777
 778   // Note: This processes all .res files before all objs. Ideally they'd be
 779   // handled in the same order they were linked (to keep the right one, if
 780   // there are duplicates that are tolerated due to forceMultipleRes).
 781   for (ObjFile *f : objs) {
 782     object::ResourceSectionRef rsf;
 783     if (auto ec = rsf.load(f->getCOFFObj()))
 784       fatal(toString(f) + ": " + toString(std::move(ec)));
 785
 786     if (auto ec = parser.parse(rsf, f->getName(), duplicates))
 787       fatal(toString(std::move(ec)));
 788   }
 789
 790   if (ctx.config.mingw)
 791     parser.cleanUpManifests(duplicates);
 792
 793   for (const auto &dupeDiag : duplicates)
 794     if (ctx.config.forceMultipleRes)
 795       warn(dupeDiag);
 796     else
 797       error(dupeDiag);
 798
 799   Expected<std::unique_ptr<MemoryBuffer>> e =
 800       llvm::object::writeWindowsResourceCOFF(ctx.config.machine, parser,
 801                                              ctx.config.timestamp);
 802   if (!e)
 803     fatal("failed to write .res to COFF: " + toString(e.takeError()));
 804
 805   MemoryBufferRef mbref = **e;
 806   make<std::unique_ptr<MemoryBuffer>>(std::move(*e)); // take ownership
 807   return mbref;
 808 }
 809
 810 // Create OptTable
 811
 812 // Create prefix string literals used in Options.td
 813 #define PREFIX(NAME, VALUE)                                                    \
 814   static constexpr llvm::StringLiteral NAME##_init[] = VALUE;                  \
 815   static constexpr llvm::ArrayRef<llvm::StringLiteral> NAME(                   \
 816       NAME##_init, std::size(NAME##_init) - 1);
 817 #include "Options.inc"
 818 #undef PREFIX
 819
 820 // Create table mapping all options defined in Options.td
 821 static constexpr llvm::opt::OptTable::Info infoTable[] = {
 822 #define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
 823 #include "Options.inc"
 824 #undef OPTION
 825 };
 826
 827 COFFOptTable::COFFOptTable() : GenericOptTable(infoTable, true) {}
 828
 829 // Set color diagnostics according to --color-diagnostics={auto,always,never}
 830 // or --no-color-diagnostics flags.
 831 static void handleColorDiagnostics(opt::InputArgList &args) {
 832   auto *arg = args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
 833                               OPT_no_color_diagnostics);
 834   if (!arg)
 835     return;
 836   if (arg->getOption().getID() == OPT_color_diagnostics) {
 837     lld::errs().enable_colors(true);
 838   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
 839     lld::errs().enable_colors(false);
 840   } else {
 841     StringRef s = arg->getValue();
 842     if (s == "always")
 843       lld::errs().enable_colors(true);
 844     else if (s == "never")
 845       lld::errs().enable_colors(false);
 846     else if (s != "auto")
 847       error("unknown option: --color-diagnostics=" + s);
 848   }
 849 }
 850
 851 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &args) {
 852   if (auto *arg = args.getLastArg(OPT_rsp_quoting)) {
 853     StringRef s = arg->getValue();
 854     if (s != "windows" && s != "posix")
 855       error("invalid response file quoting: " + s);
 856     if (s == "windows")
 857       return cl::TokenizeWindowsCommandLine;
 858     return cl::TokenizeGNUCommandLine;
 859   }
 860   // The COFF linker always defaults to Windows quoting.
 861   return cl::TokenizeWindowsCommandLine;
 862 }
 863
 864 ArgParser::ArgParser(COFFLinkerContext &c) : ctx(c) {}
 865
 866 // Parses a given list of options.
 867 opt::InputArgList ArgParser::parse(ArrayRef<const char *> argv) {
 868   // Make InputArgList from string vectors.
 869   unsigned missingIndex;
 870   unsigned missingCount;
 871
 872   // We need to get the quoting style for response files before parsing all
 873   // options so we parse here before and ignore all the options but
 874   // --rsp-quoting and /lldignoreenv.
 875   // (This means --rsp-quoting can't be added through %LINK%.)
 876   opt::InputArgList args =
 877       ctx.optTable.ParseArgs(argv, missingIndex, missingCount);
 878
 879   // Expand response files (arguments in the form of @<filename>) and insert
 880   // flags from %LINK% and %_LINK_%, and then parse the argument again.
 881   SmallVector<const char *, 256> expandedArgv(argv.data(),
 882                                               argv.data() + argv.size());
 883   if (!args.hasArg(OPT_lldignoreenv))
 884     addLINK(expandedArgv);
 885   cl::ExpandResponseFiles(saver(), getQuotingStyle(args), expandedArgv);
 886   args = ctx.optTable.ParseArgs(ArrayRef(expandedArgv).drop_front(),
 887                                 missingIndex, missingCount);
 888
 889   // Print the real command line if response files are expanded.
 890   if (args.hasArg(OPT_verbose) && argv.size() != expandedArgv.size()) {
 891     std::string msg = "Command line:";
 892     for (const char *s : expandedArgv)
 893       msg += " " + std::string(s);
 894     message(msg);
 895   }
 896
 897   // Save the command line after response file expansion so we can write it to
 898   // the PDB if necessary. Mimic MSVC, which skips input files.
 899   ctx.config.argv = {argv[0]};
 900   for (opt::Arg *arg : args) {
 901     if (arg->getOption().getKind() != opt::Option::InputClass) {
 902       ctx.config.argv.emplace_back(args.getArgString(arg->getIndex()));
 903     }
 904   }
 905
 906   // Handle /WX early since it converts missing argument warnings to errors.
 907   errorHandler().fatalWarnings = args.hasFlag(OPT_WX, OPT_WX_no, false);
 908
 909   if (missingCount)
 910     fatal(Twine(args.getArgString(missingIndex)) + ": missing argument");
 911
 912   handleColorDiagnostics(args);
 913
 914   for (opt::Arg *arg : args.filtered(OPT_UNKNOWN)) {
 915     std::string nearest;
 916     if (ctx.optTable.findNearest(arg->getAsString(args), nearest) > 1)
 917       warn("ignoring unknown argument '" + arg->getAsString(args) + "'");
 918     else
 919       warn("ignoring unknown argument '" + arg->getAsString(args) +
 920            "', did you mean '" + nearest + "'");
 921   }
 922
 923   if (args.hasArg(OPT_lib))
 924     warn("ignoring /lib since it's not the first argument");
 925
 926   return args;
 927 }
 928
 929 // Tokenizes and parses a given string as command line in .drective section.
 930 ParsedDirectives ArgParser::parseDirectives(StringRef s) {
 931   ParsedDirectives result;
 932   SmallVector<const char *, 16> rest;
 933
 934   // Handle /EXPORT and /INCLUDE in a fast path. These directives can appear for
 935   // potentially every symbol in the object, so they must be handled quickly.
 936   SmallVector<StringRef, 16> tokens;
 937   cl::TokenizeWindowsCommandLineNoCopy(s, saver(), tokens);
 938   for (StringRef tok : tokens) {
 939     if (tok.starts_with_insensitive("/export:") ||
 940         tok.starts_with_insensitive("-export:"))
 941       result.exports.push_back(tok.substr(strlen("/export:")));
 942     else if (tok.starts_with_insensitive("/include:") ||
 943              tok.starts_with_insensitive("-include:"))
 944       result.includes.push_back(tok.substr(strlen("/include:")));
 945     else if (tok.starts_with_insensitive("/exclude-symbols:") ||
 946              tok.starts_with_insensitive("-exclude-symbols:"))
 947       result.excludes.push_back(tok.substr(strlen("/exclude-symbols:")));
 948     else {
 949       // Copy substrings that are not valid C strings. The tokenizer may have
 950       // already copied quoted arguments for us, so those do not need to be
 951       // copied again.
 952       bool HasNul = tok.end() != s.end() && tok.data()[tok.size()] == '\0';
 953       rest.push_back(HasNul ? tok.data() : saver().save(tok).data());
 954     }
 955   }
 956
 957   // Make InputArgList from unparsed string vectors.
 958   unsigned missingIndex;
 959   unsigned missingCount;
 960
 961   result.args = ctx.optTable.ParseArgs(rest, missingIndex, missingCount);
 962
 963   if (missingCount)
 964     fatal(Twine(result.args.getArgString(missingIndex)) + ": missing argument");
 965   for (auto *arg : result.args.filtered(OPT_UNKNOWN))
 966     warn("ignoring unknown argument: " + arg->getAsString(result.args));
 967   return result;
 968 }
 969
 970 // link.exe has an interesting feature. If LINK or _LINK_ environment
 971 // variables exist, their contents are handled as command line strings.
 972 // So you can pass extra arguments using them.
 973 void ArgParser::addLINK(SmallVector<const char *, 256> &argv) {
 974   // Concatenate LINK env and command line arguments, and then parse them.
 975   if (std::optional<std::string> s = Process::GetEnv("LINK")) {
 976     std::vector<const char *> v = tokenize(*s);
 977     argv.insert(std::next(argv.begin()), v.begin(), v.end());
 978   }
 979   if (std::optional<std::string> s = Process::GetEnv("_LINK_")) {
 980     std::vector<const char *> v = tokenize(*s);
 981     argv.insert(std::next(argv.begin()), v.begin(), v.end());
 982   }
 983 }
 984
 985 std::vector<const char *> ArgParser::tokenize(StringRef s) {
 986   SmallVector<const char *, 16> tokens;
 987   cl::TokenizeWindowsCommandLine(s, saver(), tokens);
 988   return std::vector<const char *>(tokens.begin(), tokens.end());
 989 }
 990
 991 void LinkerDriver::printHelp(const char *argv0) {
 992   ctx.optTable.printHelp(lld::outs(),
 993                          (std::string(argv0) + " [options] file...").c_str(),
 994                          "LLVM Linker", false);
 995 }
 996
 997 } // namespace coff
 998 } // namespace lld