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/IR/Mangler.h"
  25 #include "llvm/Object/COFF.h"
  26 #include "llvm/Object/WindowsResource.h"
  27 #include "llvm/Option/Arg.h"
  28 #include "llvm/Option/ArgList.h"
  29 #include "llvm/Option/Option.h"
  30 #include "llvm/Support/CommandLine.h"
  31 #include "llvm/Support/FileUtilities.h"
  32 #include "llvm/Support/MathExtras.h"
  33 #include "llvm/Support/Process.h"
  34 #include "llvm/Support/Program.h"
  35 #include "llvm/Support/TimeProfiler.h"
  36 #include "llvm/Support/raw_ostream.h"
  37 #include "llvm/WindowsManifest/WindowsManifestMerger.h"
  38 #include <limits>
  39 #include <memory>
  40 #include <optional>
  41
  42 using namespace llvm::COFF;
  43 using namespace llvm::object;
  44 using namespace llvm::opt;
  45 using namespace llvm;
  46 using llvm::sys::Process;
  47
  48 namespace lld {
  49 namespace coff {
  50 namespace {
  51
  52 const uint16_t SUBLANG_ENGLISH_US = 0x0409;
  53 const uint16_t RT_MANIFEST = 24;
  54
  55 class Executor {
  56 public:
  57   explicit Executor(StringRef s) : prog(saver().save(s)) {}
  58   void add(StringRef s) { args.push_back(saver().save(s)); }
  59   void add(std::string &s) { args.push_back(saver().save(s)); }
  60   void add(Twine s) { args.push_back(saver().save(s)); }
  61   void add(const char *s) { args.push_back(saver().save(s)); }
  62
  63   void run() {
  64     ErrorOr<std::string> exeOrErr = sys::findProgramByName(prog);
  65     if (auto ec = exeOrErr.getError())
  66       fatal("unable to find " + prog + " in PATH: " + ec.message());
  67     StringRef exe = saver().save(*exeOrErr);
  68     args.insert(args.begin(), exe);
  69
  70     if (sys::ExecuteAndWait(args[0], args) != 0)
  71       fatal("ExecuteAndWait failed: " +
  72             llvm::join(args.begin(), args.end(), " "));
  73   }
  74
  75 private:
  76   StringRef prog;
  77   std::vector<StringRef> args;
  78 };
  79
  80 } // anonymous namespace
  81
  82 // Parses a string in the form of "<integer>[,<integer>]".
  83 void LinkerDriver::parseNumbers(StringRef arg, uint64_t *addr, uint64_t *size) {
  84   auto [s1, s2] = arg.split(',');
  85   if (s1.getAsInteger(0, *addr))
  86     fatal("invalid number: " + s1);
  87   if (size && !s2.empty() && s2.getAsInteger(0, *size))
  88     fatal("invalid number: " + s2);
  89 }
  90
  91 // Parses a string in the form of "<integer>[.<integer>]".
  92 // If second number is not present, Minor is set to 0.
  93 void LinkerDriver::parseVersion(StringRef arg, uint32_t *major,
  94                                 uint32_t *minor) {
  95   auto [s1, s2] = arg.split('.');
  96   if (s1.getAsInteger(10, *major))
  97     fatal("invalid number: " + s1);
  98   *minor = 0;
  99   if (!s2.empty() && s2.getAsInteger(10, *minor))
 100     fatal("invalid number: " + s2);
 101 }
 102
 103 void LinkerDriver::parseGuard(StringRef fullArg) {
 104   SmallVector<StringRef, 1> splitArgs;
 105   fullArg.split(splitArgs, ",");
 106   for (StringRef arg : splitArgs) {
 107     if (arg.equals_insensitive("no"))
 108       ctx.config.guardCF = GuardCFLevel::Off;
 109     else if (arg.equals_insensitive("nolongjmp"))
 110       ctx.config.guardCF &= ~GuardCFLevel::LongJmp;
 111     else if (arg.equals_insensitive("noehcont"))
 112       ctx.config.guardCF &= ~GuardCFLevel::EHCont;
 113     else if (arg.equals_insensitive("cf") || arg.equals_insensitive("longjmp"))
 114       ctx.config.guardCF |= GuardCFLevel::CF | GuardCFLevel::LongJmp;
 115     else if (arg.equals_insensitive("ehcont"))
 116       ctx.config.guardCF |= GuardCFLevel::CF | GuardCFLevel::EHCont;
 117     else
 118       fatal("invalid argument to /guard: " + arg);
 119   }
 120 }
 121
 122 // Parses a string in the form of "<subsystem>[,<integer>[.<integer>]]".
 123 void LinkerDriver::parseSubsystem(StringRef arg, WindowsSubsystem *sys,
 124                                   uint32_t *major, uint32_t *minor,
 125                                   bool *gotVersion) {
 126   auto [sysStr, ver] = arg.split(',');
 127   std::string sysStrLower = sysStr.lower();
 128   *sys = StringSwitch<WindowsSubsystem>(sysStrLower)
 129     .Case("boot_application", IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION)
 130     .Case("console", IMAGE_SUBSYSTEM_WINDOWS_CUI)
 131     .Case("default", IMAGE_SUBSYSTEM_UNKNOWN)
 132     .Case("efi_application", IMAGE_SUBSYSTEM_EFI_APPLICATION)
 133     .Case("efi_boot_service_driver", IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER)
 134     .Case("efi_rom", IMAGE_SUBSYSTEM_EFI_ROM)
 135     .Case("efi_runtime_driver", IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER)
 136     .Case("native", IMAGE_SUBSYSTEM_NATIVE)
 137     .Case("posix", IMAGE_SUBSYSTEM_POSIX_CUI)
 138     .Case("windows", IMAGE_SUBSYSTEM_WINDOWS_GUI)
 139     .Default(IMAGE_SUBSYSTEM_UNKNOWN);
 140   if (*sys == IMAGE_SUBSYSTEM_UNKNOWN && sysStrLower != "default")
 141     fatal("unknown subsystem: " + sysStr);
 142   if (!ver.empty())
 143     parseVersion(ver, major, minor);
 144   if (gotVersion)
 145     *gotVersion = !ver.empty();
 146 }
 147
 148 // Parse a string of the form of "<from>=<to>".
 149 // Results are directly written to Config.
 150 void LinkerDriver::parseAlternateName(StringRef s) {
 151   auto [from, to] = s.split('=');
 152   if (from.empty() || to.empty())
 153     fatal("/alternatename: invalid argument: " + s);
 154   auto it = ctx.config.alternateNames.find(from);
 155   if (it != ctx.config.alternateNames.end() && it->second != to)
 156     fatal("/alternatename: conflicts: " + s);
 157   ctx.config.alternateNames.insert(it, std::make_pair(from, to));
 158 }
 159
 160 // Parse a string of the form of "<from>=<to>".
 161 // Results are directly written to Config.
 162 void LinkerDriver::parseMerge(StringRef s) {
 163   auto [from, to] = s.split('=');
 164   if (from.empty() || to.empty())
 165     fatal("/merge: invalid argument: " + s);
 166   if (from == ".rsrc" || to == ".rsrc")
 167     fatal("/merge: cannot merge '.rsrc' with any section");
 168   if (from == ".reloc" || to == ".reloc")
 169     fatal("/merge: cannot merge '.reloc' with any section");
 170   auto pair = ctx.config.merge.insert(std::make_pair(from, to));
 171   bool inserted = pair.second;
 172   if (!inserted) {
 173     StringRef existing = pair.first->second;
 174     if (existing != to)
 175       warn(s + ": already merged into " + existing);
 176   }
 177 }
 178
 179 void LinkerDriver::parsePDBPageSize(StringRef s) {
 180   int v;
 181   if (s.getAsInteger(0, v)) {
 182     error("/pdbpagesize: invalid argument: " + s);
 183     return;
 184   }
 185   if (v != 4096 && v != 8192 && v != 16384 && v != 32768) {
 186     error("/pdbpagesize: invalid argument: " + s);
 187     return;
 188   }
 189
 190   ctx.config.pdbPageSize = v;
 191 }
 192
 193 static uint32_t parseSectionAttributes(StringRef s) {
 194   uint32_t ret = 0;
 195   for (char c : s.lower()) {
 196     switch (c) {
 197     case 'd':
 198       ret |= IMAGE_SCN_MEM_DISCARDABLE;
 199       break;
 200     case 'e':
 201       ret |= IMAGE_SCN_MEM_EXECUTE;
 202       break;
 203     case 'k':
 204       ret |= IMAGE_SCN_MEM_NOT_CACHED;
 205       break;
 206     case 'p':
 207       ret |= IMAGE_SCN_MEM_NOT_PAGED;
 208       break;
 209     case 'r':
 210       ret |= IMAGE_SCN_MEM_READ;
 211       break;
 212     case 's':
 213       ret |= IMAGE_SCN_MEM_SHARED;
 214       break;
 215     case 'w':
 216       ret |= IMAGE_SCN_MEM_WRITE;
 217       break;
 218     default:
 219       fatal("/section: invalid argument: " + s);
 220     }
 221   }
 222   return ret;
 223 }
 224
 225 // Parses /section option argument.
 226 void LinkerDriver::parseSection(StringRef s) {
 227   auto [name, attrs] = s.split(',');
 228   if (name.empty() || attrs.empty())
 229     fatal("/section: invalid argument: " + s);
 230   ctx.config.section[name] = parseSectionAttributes(attrs);
 231 }
 232
 233 // Parses /aligncomm option argument.
 234 void LinkerDriver::parseAligncomm(StringRef s) {
 235   auto [name, align] = s.split(',');
 236   if (name.empty() || align.empty()) {
 237     error("/aligncomm: invalid argument: " + s);
 238     return;
 239   }
 240   int v;
 241   if (align.getAsInteger(0, v)) {
 242     error("/aligncomm: invalid argument: " + s);
 243     return;
 244   }
 245   ctx.config.alignComm[std::string(name)] =
 246       std::max(ctx.config.alignComm[std::string(name)], 1 << v);
 247 }
 248
 249 // Parses /functionpadmin option argument.
 250 void LinkerDriver::parseFunctionPadMin(llvm::opt::Arg *a) {
 251   StringRef arg = a->getNumValues() ? a->getValue() : "";
 252   if (!arg.empty()) {
 253     // Optional padding in bytes is given.
 254     if (arg.getAsInteger(0, ctx.config.functionPadMin))
 255       error("/functionpadmin: invalid argument: " + arg);
 256     return;
 257   }
 258   // No optional argument given.
 259   // Set default padding based on machine, similar to link.exe.
 260   // There is no default padding for ARM platforms.
 261   if (ctx.config.machine == I386) {
 262     ctx.config.functionPadMin = 5;
 263   } else if (ctx.config.machine == AMD64) {
 264     ctx.config.functionPadMin = 6;
 265   } else {
 266     error("/functionpadmin: invalid argument for this machine: " + arg);
 267   }
 268 }
 269
 270 // Parses /dependentloadflag option argument.
 271 void LinkerDriver::parseDependentLoadFlags(llvm::opt::Arg *a) {
 272   StringRef arg = a->getNumValues() ? a->getValue() : "";
 273   if (!arg.empty()) {
 274     if (arg.getAsInteger(0, ctx.config.dependentLoadFlags))
 275       error("/dependentloadflag: invalid argument: " + arg);
 276     return;
 277   }
 278   // MSVC linker reports error "no argument specified", although MSDN describes
 279   // argument as optional.
 280   error("/dependentloadflag: no argument specified");
 281 }
 282
 283 // Parses a string in the form of "EMBED[,=<integer>]|NO".
 284 // Results are directly written to
 285 // Config.
 286 void LinkerDriver::parseManifest(StringRef arg) {
 287   if (arg.equals_insensitive("no")) {
 288     ctx.config.manifest = Configuration::No;
 289     return;
 290   }
 291   if (!arg.starts_with_insensitive("embed"))
 292     fatal("invalid option " + arg);
 293   ctx.config.manifest = Configuration::Embed;
 294   arg = arg.substr(strlen("embed"));
 295   if (arg.empty())
 296     return;
 297   if (!arg.starts_with_insensitive(",id="))
 298     fatal("invalid option " + arg);
 299   arg = arg.substr(strlen(",id="));
 300   if (arg.getAsInteger(0, ctx.config.manifestID))
 301     fatal("invalid option " + arg);
 302 }
 303
 304 // Parses a string in the form of "level=<string>|uiAccess=<string>|NO".
 305 // Results are directly written to Config.
 306 void LinkerDriver::parseManifestUAC(StringRef arg) {
 307   if (arg.equals_insensitive("no")) {
 308     ctx.config.manifestUAC = false;
 309     return;
 310   }
 311   for (;;) {
 312     arg = arg.ltrim();
 313     if (arg.empty())
 314       return;
 315     if (arg.consume_front_insensitive("level=")) {
 316       std::tie(ctx.config.manifestLevel, arg) = arg.split(" ");
 317       continue;
 318     }
 319     if (arg.consume_front_insensitive("uiaccess=")) {
 320       std::tie(ctx.config.manifestUIAccess, arg) = arg.split(" ");
 321       continue;
 322     }
 323     fatal("invalid option " + arg);
 324   }
 325 }
 326
 327 // Parses a string in the form of "cd|net[,(cd|net)]*"
 328 // Results are directly written to Config.
 329 void LinkerDriver::parseSwaprun(StringRef arg) {
 330   do {
 331     auto [swaprun, newArg] = arg.split(',');
 332     if (swaprun.equals_insensitive("cd"))
 333       ctx.config.swaprunCD = true;
 334     else if (swaprun.equals_insensitive("net"))
 335       ctx.config.swaprunNet = true;
 336     else if (swaprun.empty())
 337       error("/swaprun: missing argument");
 338     else
 339       error("/swaprun: invalid argument: " + swaprun);
 340     // To catch trailing commas, e.g. `/spawrun:cd,`
 341     if (newArg.empty() && arg.ends_with(","))
 342       error("/swaprun: missing argument");
 343     arg = newArg;
 344   } while (!arg.empty());
 345 }
 346
 347 // An RAII temporary file class that automatically removes a temporary file.
 348 namespace {
 349 class TemporaryFile {
 350 public:
 351   TemporaryFile(StringRef prefix, StringRef extn, StringRef contents = "") {
 352     SmallString<128> s;
 353     if (auto ec = sys::fs::createTemporaryFile("lld-" + prefix, extn, s))
 354       fatal("cannot create a temporary file: " + ec.message());
 355     path = std::string(s);
 356
 357     if (!contents.empty()) {
 358       std::error_code ec;
 359       raw_fd_ostream os(path, ec, sys::fs::OF_None);
 360       if (ec)
 361         fatal("failed to open " + path + ": " + ec.message());
 362       os << contents;
 363     }
 364   }
 365
 366   TemporaryFile(TemporaryFile &&obj) noexcept { std::swap(path, obj.path); }
 367
 368   ~TemporaryFile() {
 369     if (path.empty())
 370       return;
 371     if (sys::fs::remove(path))
 372       fatal("failed to remove " + path);
 373   }
 374
 375   // Returns a memory buffer of this temporary file.
 376   // Note that this function does not leave the file open,
 377   // so it is safe to remove the file immediately after this function
 378   // is called (you cannot remove an opened file on Windows.)
 379   std::unique_ptr<MemoryBuffer> getMemoryBuffer() {
 380     // IsVolatile=true forces MemoryBuffer to not use mmap().
 381     return CHECK(MemoryBuffer::getFile(path, /*IsText=*/false,
 382                                        /*RequiresNullTerminator=*/false,
 383                                        /*IsVolatile=*/true),
 384                  "could not open " + path);
 385   }
 386
 387   std::string path;
 388 };
 389 }
 390
 391 std::string LinkerDriver::createDefaultXml() {
 392   std::string ret;
 393   raw_string_ostream os(ret);
 394
 395   // Emit the XML. Note that we do *not* verify that the XML attributes are
 396   // syntactically correct. This is intentional for link.exe compatibility.
 397   os << "<?xml version=\"1.0\" standalone=\"yes\"?>\n"
 398      << "<assembly xmlns=\"urn:schemas-microsoft-com:asm.v1\"\n"
 399      << "          manifestVersion=\"1.0\">\n";
 400   if (ctx.config.manifestUAC) {
 401     os << "  <trustInfo>\n"
 402        << "    <security>\n"
 403        << "      <requestedPrivileges>\n"
 404        << "         <requestedExecutionLevel level=" << ctx.config.manifestLevel
 405        << " uiAccess=" << ctx.config.manifestUIAccess << "/>\n"
 406        << "      </requestedPrivileges>\n"
 407        << "    </security>\n"
 408        << "  </trustInfo>\n";
 409   }
 410   for (auto manifestDependency : ctx.config.manifestDependencies) {
 411     os << "  <dependency>\n"
 412        << "    <dependentAssembly>\n"
 413        << "      <assemblyIdentity " << manifestDependency << " />\n"
 414        << "    </dependentAssembly>\n"
 415        << "  </dependency>\n";
 416   }
 417   os << "</assembly>\n";
 418   return ret;
 419 }
 420
 421 std::string
 422 LinkerDriver::createManifestXmlWithInternalMt(StringRef defaultXml) {
 423   std::unique_ptr<MemoryBuffer> defaultXmlCopy =
 424       MemoryBuffer::getMemBufferCopy(defaultXml);
 425
 426   windows_manifest::WindowsManifestMerger merger;
 427   if (auto e = merger.merge(*defaultXmlCopy.get()))
 428     fatal("internal manifest tool failed on default xml: " +
 429           toString(std::move(e)));
 430
 431   for (StringRef filename : ctx.config.manifestInput) {
 432     std::unique_ptr<MemoryBuffer> manifest =
 433         check(MemoryBuffer::getFile(filename));
 434     // Call takeBuffer to include in /reproduce: output if applicable.
 435     if (auto e = merger.merge(takeBuffer(std::move(manifest))))
 436       fatal("internal manifest tool failed on file " + filename + ": " +
 437             toString(std::move(e)));
 438   }
 439
 440   return std::string(merger.getMergedManifest().get()->getBuffer());
 441 }
 442
 443 std::string
 444 LinkerDriver::createManifestXmlWithExternalMt(StringRef defaultXml) {
 445   // Create the default manifest file as a temporary file.
 446   TemporaryFile Default("defaultxml", "manifest");
 447   std::error_code ec;
 448   raw_fd_ostream os(Default.path, ec, sys::fs::OF_TextWithCRLF);
 449   if (ec)
 450     fatal("failed to open " + Default.path + ": " + ec.message());
 451   os << defaultXml;
 452   os.close();
 453
 454   // Merge user-supplied manifests if they are given.  Since libxml2 is not
 455   // enabled, we must shell out to Microsoft's mt.exe tool.
 456   TemporaryFile user("user", "manifest");
 457
 458   Executor e("mt.exe");
 459   e.add("/manifest");
 460   e.add(Default.path);
 461   for (StringRef filename : ctx.config.manifestInput) {
 462     e.add("/manifest");
 463     e.add(filename);
 464
 465     // Manually add the file to the /reproduce: tar if needed.
 466     if (tar)
 467       if (auto mbOrErr = MemoryBuffer::getFile(filename))
 468         takeBuffer(std::move(*mbOrErr));
 469   }
 470   e.add("/nologo");
 471   e.add("/out:" + StringRef(user.path));
 472   e.run();
 473
 474   return std::string(
 475       CHECK(MemoryBuffer::getFile(user.path), "could not open " + user.path)
 476           .get()
 477           ->getBuffer());
 478 }
 479
 480 std::string LinkerDriver::createManifestXml() {
 481   std::string defaultXml = createDefaultXml();
 482   if (ctx.config.manifestInput.empty())
 483     return defaultXml;
 484
 485   if (windows_manifest::isAvailable())
 486     return createManifestXmlWithInternalMt(defaultXml);
 487
 488   return createManifestXmlWithExternalMt(defaultXml);
 489 }
 490
 491 std::unique_ptr<WritableMemoryBuffer>
 492 LinkerDriver::createMemoryBufferForManifestRes(size_t manifestSize) {
 493   size_t resSize = alignTo(
 494       object::WIN_RES_MAGIC_SIZE + object::WIN_RES_NULL_ENTRY_SIZE +
 495           sizeof(object::WinResHeaderPrefix) + sizeof(object::WinResIDs) +
 496           sizeof(object::WinResHeaderSuffix) + manifestSize,
 497       object::WIN_RES_DATA_ALIGNMENT);
 498   return WritableMemoryBuffer::getNewMemBuffer(resSize, ctx.config.outputFile +
 499                                                             ".manifest.res");
 500 }
 501
 502 static void writeResFileHeader(char *&buf) {
 503   memcpy(buf, COFF::WinResMagic, sizeof(COFF::WinResMagic));
 504   buf += sizeof(COFF::WinResMagic);
 505   memset(buf, 0, object::WIN_RES_NULL_ENTRY_SIZE);
 506   buf += object::WIN_RES_NULL_ENTRY_SIZE;
 507 }
 508
 509 static void writeResEntryHeader(char *&buf, size_t manifestSize,
 510                                 int manifestID) {
 511   // Write the prefix.
 512   auto *prefix = reinterpret_cast<object::WinResHeaderPrefix *>(buf);
 513   prefix->DataSize = manifestSize;
 514   prefix->HeaderSize = sizeof(object::WinResHeaderPrefix) +
 515                        sizeof(object::WinResIDs) +
 516                        sizeof(object::WinResHeaderSuffix);
 517   buf += sizeof(object::WinResHeaderPrefix);
 518
 519   // Write the Type/Name IDs.
 520   auto *iDs = reinterpret_cast<object::WinResIDs *>(buf);
 521   iDs->setType(RT_MANIFEST);
 522   iDs->setName(manifestID);
 523   buf += sizeof(object::WinResIDs);
 524
 525   // Write the suffix.
 526   auto *suffix = reinterpret_cast<object::WinResHeaderSuffix *>(buf);
 527   suffix->DataVersion = 0;
 528   suffix->MemoryFlags = object::WIN_RES_PURE_MOVEABLE;
 529   suffix->Language = SUBLANG_ENGLISH_US;
 530   suffix->Version = 0;
 531   suffix->Characteristics = 0;
 532   buf += sizeof(object::WinResHeaderSuffix);
 533 }
 534
 535 // Create a resource file containing a manifest XML.
 536 std::unique_ptr<MemoryBuffer> LinkerDriver::createManifestRes() {
 537   std::string manifest = createManifestXml();
 538
 539   std::unique_ptr<WritableMemoryBuffer> res =
 540       createMemoryBufferForManifestRes(manifest.size());
 541
 542   char *buf = res->getBufferStart();
 543   writeResFileHeader(buf);
 544   writeResEntryHeader(buf, manifest.size(), ctx.config.manifestID);
 545
 546   // Copy the manifest data into the .res file.
 547   std::copy(manifest.begin(), manifest.end(), buf);
 548   return std::move(res);
 549 }
 550
 551 void LinkerDriver::createSideBySideManifest() {
 552   std::string path = std::string(ctx.config.manifestFile);
 553   if (path == "")
 554     path = ctx.config.outputFile + ".manifest";
 555   std::error_code ec;
 556   raw_fd_ostream out(path, ec, sys::fs::OF_TextWithCRLF);
 557   if (ec)
 558     fatal("failed to create manifest: " + ec.message());
 559   out << createManifestXml();
 560 }
 561
 562 // Parse a string in the form of
 563 // "<name>[=<internalname>][,@ordinal[,NONAME]][,DATA][,PRIVATE]"
 564 // or "<name>=<dllname>.<name>".
 565 // Used for parsing /export arguments.
 566 Export LinkerDriver::parseExport(StringRef arg) {
 567   Export e;
 568   e.source = ExportSource::Export;
 569
 570   StringRef rest;
 571   std::tie(e.name, rest) = arg.split(",");
 572   if (e.name.empty())
 573     goto err;
 574
 575   if (e.name.contains('=')) {
 576     auto [x, y] = e.name.split("=");
 577
 578     // If "<name>=<dllname>.<name>".
 579     if (y.contains(".")) {
 580       e.name = x;
 581       e.forwardTo = y;
 582     } else {
 583       e.extName = x;
 584       e.name = y;
 585       if (e.name.empty())
 586         goto err;
 587     }
 588   }
 589
 590   // Optional parameters
 591   // "[,@ordinal[,NONAME]][,DATA][,PRIVATE][,EXPORTAS,exportname]"
 592   while (!rest.empty()) {
 593     StringRef tok;
 594     std::tie(tok, rest) = rest.split(",");
 595     if (tok.equals_insensitive("noname")) {
 596       if (e.ordinal == 0)
 597         goto err;
 598       e.noname = true;
 599       continue;
 600     }
 601     if (tok.equals_insensitive("data")) {
 602       e.data = true;
 603       continue;
 604     }
 605     if (tok.equals_insensitive("constant")) {
 606       e.constant = true;
 607       continue;
 608     }
 609     if (tok.equals_insensitive("private")) {
 610       e.isPrivate = true;
 611       continue;
 612     }
 613     if (tok.equals_insensitive("exportas")) {
 614       if (!rest.empty() && !rest.contains(','))
 615         e.exportAs = rest;
 616       else
 617         error("invalid EXPORTAS value: " + rest);
 618       break;
 619     }
 620     if (tok.starts_with("@")) {
 621       int32_t ord;
 622       if (tok.substr(1).getAsInteger(0, ord))
 623         goto err;
 624       if (ord <= 0 || 65535 < ord)
 625         goto err;
 626       e.ordinal = ord;
 627       continue;
 628     }
 629     goto err;
 630   }
 631   return e;
 632
 633 err:
 634   fatal("invalid /export: " + arg);
 635 }
 636
 637 // Convert stdcall/fastcall style symbols into unsuffixed symbols,
 638 // with or without a leading underscore. (MinGW specific.)
 639 static StringRef killAt(StringRef sym, bool prefix) {
 640   if (sym.empty())
 641     return sym;
 642   // Strip any trailing stdcall suffix
 643   sym = sym.substr(0, sym.find('@', 1));
 644   if (!sym.starts_with("@")) {
 645     if (prefix && !sym.starts_with("_"))
 646       return saver().save("_" + sym);
 647     return sym;
 648   }
 649   // For fastcall, remove the leading @ and replace it with an
 650   // underscore, if prefixes are used.
 651   sym = sym.substr(1);
 652   if (prefix)
 653     sym = saver().save("_" + sym);
 654   return sym;
 655 }
 656
 657 static StringRef exportSourceName(ExportSource s) {
 658   switch (s) {
 659   case ExportSource::Directives:
 660     return "source file (directives)";
 661   case ExportSource::Export:
 662     return "/export";
 663   case ExportSource::ModuleDefinition:
 664     return "/def";
 665   default:
 666     llvm_unreachable("unknown ExportSource");
 667   }
 668 }
 669
 670 // Performs error checking on all /export arguments.
 671 // It also sets ordinals.
 672 void LinkerDriver::fixupExports() {
 673   llvm::TimeTraceScope timeScope("Fixup exports");
 674   // Symbol ordinals must be unique.
 675   std::set<uint16_t> ords;
 676   for (Export &e : ctx.config.exports) {
 677     if (e.ordinal == 0)
 678       continue;
 679     if (!ords.insert(e.ordinal).second)
 680       fatal("duplicate export ordinal: " + e.name);
 681   }
 682
 683   for (Export &e : ctx.config.exports) {
 684     if (!e.exportAs.empty()) {
 685       e.exportName = e.exportAs;
 686       continue;
 687     }
 688
 689     StringRef sym =
 690         !e.forwardTo.empty() || e.extName.empty() ? e.name : e.extName;
 691     if (ctx.config.machine == I386 && sym.starts_with("_")) {
 692       // In MSVC mode, a fully decorated stdcall function is exported
 693       // as-is with the leading underscore (with type IMPORT_NAME).
 694       // In MinGW mode, a decorated stdcall function gets the underscore
 695       // removed, just like normal cdecl functions.
 696       if (ctx.config.mingw || !sym.contains('@')) {
 697         e.exportName = sym.substr(1);
 698         continue;
 699       }
 700     }
 701     if (isArm64EC(ctx.config.machine) && !e.data && !e.constant) {
 702       if (std::optional<std::string> demangledName =
 703               getArm64ECDemangledFunctionName(sym)) {
 704         e.exportName = saver().save(*demangledName);
 705         continue;
 706       }
 707     }
 708     e.exportName = sym;
 709   }
 710
 711   if (ctx.config.killAt && ctx.config.machine == I386) {
 712     for (Export &e : ctx.config.exports) {
 713       e.name = killAt(e.name, true);
 714       e.exportName = killAt(e.exportName, false);
 715       e.extName = killAt(e.extName, true);
 716       e.symbolName = killAt(e.symbolName, true);
 717     }
 718   }
 719
 720   // Uniquefy by name.
 721   DenseMap<StringRef, std::pair<Export *, unsigned>> map(
 722       ctx.config.exports.size());
 723   std::vector<Export> v;
 724   for (Export &e : ctx.config.exports) {
 725     auto pair = map.insert(std::make_pair(e.exportName, std::make_pair(&e, 0)));
 726     bool inserted = pair.second;
 727     if (inserted) {
 728       pair.first->second.second = v.size();
 729       v.push_back(e);
 730       continue;
 731     }
 732     Export *existing = pair.first->second.first;
 733     if (e == *existing || e.name != existing->name)
 734       continue;
 735     // If the existing export comes from .OBJ directives, we are allowed to
 736     // overwrite it with /DEF: or /EXPORT without any warning, as MSVC link.exe
 737     // does.
 738     if (existing->source == ExportSource::Directives) {
 739       *existing = e;
 740       v[pair.first->second.second] = e;
 741       continue;
 742     }
 743     if (existing->source == e.source) {
 744       warn(Twine("duplicate ") + exportSourceName(existing->source) +
 745            " option: " + e.name);
 746     } else {
 747       warn("duplicate export: " + e.name +
 748            Twine(" first seen in " + exportSourceName(existing->source) +
 749                  Twine(", now in " + exportSourceName(e.source))));
 750     }
 751   }
 752   ctx.config.exports = std::move(v);
 753
 754   // Sort by name.
 755   llvm::sort(ctx.config.exports, [](const Export &a, const Export &b) {
 756     return a.exportName < b.exportName;
 757   });
 758 }
 759
 760 void LinkerDriver::assignExportOrdinals() {
 761   // Assign unique ordinals if default (= 0).
 762   uint32_t max = 0;
 763   for (Export &e : ctx.config.exports)
 764     max = std::max(max, (uint32_t)e.ordinal);
 765   for (Export &e : ctx.config.exports)
 766     if (e.ordinal == 0)
 767       e.ordinal = ++max;
 768   if (max > std::numeric_limits<uint16_t>::max())
 769     fatal("too many exported symbols (got " + Twine(max) + ", max " +
 770           Twine(std::numeric_limits<uint16_t>::max()) + ")");
 771 }
 772
 773 // Parses a string in the form of "key=value" and check
 774 // if value matches previous values for the same key.
 775 void LinkerDriver::checkFailIfMismatch(StringRef arg, InputFile *source) {
 776   auto [k, v] = arg.split('=');
 777   if (k.empty() || v.empty())
 778     fatal("/failifmismatch: invalid argument: " + arg);
 779   std::pair<StringRef, InputFile *> existing = ctx.config.mustMatch[k];
 780   if (!existing.first.empty() && v != existing.first) {
 781     std::string sourceStr = source ? toString(source) : "cmd-line";
 782     std::string existingStr =
 783         existing.second ? toString(existing.second) : "cmd-line";
 784     fatal("/failifmismatch: mismatch detected for '" + k + "':\n>>> " +
 785           existingStr + " has value " + existing.first + "\n>>> " + sourceStr +
 786           " has value " + v);
 787   }
 788   ctx.config.mustMatch[k] = {v, source};
 789 }
 790
 791 // Convert Windows resource files (.res files) to a .obj file.
 792 // Does what cvtres.exe does, but in-process and cross-platform.
 793 MemoryBufferRef LinkerDriver::convertResToCOFF(ArrayRef<MemoryBufferRef> mbs,
 794                                                ArrayRef<ObjFile *> objs) {
 795   object::WindowsResourceParser parser(/* MinGW */ ctx.config.mingw);
 796
 797   std::vector<std::string> duplicates;
 798   for (MemoryBufferRef mb : mbs) {
 799     std::unique_ptr<object::Binary> bin = check(object::createBinary(mb));
 800     object::WindowsResource *rf = dyn_cast<object::WindowsResource>(bin.get());
 801     if (!rf)
 802       fatal("cannot compile non-resource file as resource");
 803
 804     if (auto ec = parser.parse(rf, duplicates))
 805       fatal(toString(std::move(ec)));
 806   }
 807
 808   // Note: This processes all .res files before all objs. Ideally they'd be
 809   // handled in the same order they were linked (to keep the right one, if
 810   // there are duplicates that are tolerated due to forceMultipleRes).
 811   for (ObjFile *f : objs) {
 812     object::ResourceSectionRef rsf;
 813     if (auto ec = rsf.load(f->getCOFFObj()))
 814       fatal(toString(f) + ": " + toString(std::move(ec)));
 815
 816     if (auto ec = parser.parse(rsf, f->getName(), duplicates))
 817       fatal(toString(std::move(ec)));
 818   }
 819
 820   if (ctx.config.mingw)
 821     parser.cleanUpManifests(duplicates);
 822
 823   for (const auto &dupeDiag : duplicates)
 824     if (ctx.config.forceMultipleRes)
 825       warn(dupeDiag);
 826     else
 827       error(dupeDiag);
 828
 829   Expected<std::unique_ptr<MemoryBuffer>> e =
 830       llvm::object::writeWindowsResourceCOFF(ctx.config.machine, parser,
 831                                              ctx.config.timestamp);
 832   if (!e)
 833     fatal("failed to write .res to COFF: " + toString(e.takeError()));
 834
 835   MemoryBufferRef mbref = **e;
 836   make<std::unique_ptr<MemoryBuffer>>(std::move(*e)); // take ownership
 837   return mbref;
 838 }
 839
 840 // Create OptTable
 841
 842 // Create prefix string literals used in Options.td
 843 #define PREFIX(NAME, VALUE)                                                    \
 844   static constexpr llvm::StringLiteral NAME##_init[] = VALUE;                  \
 845   static constexpr llvm::ArrayRef<llvm::StringLiteral> NAME(                   \
 846       NAME##_init, std::size(NAME##_init) - 1);
 847 #include "Options.inc"
 848 #undef PREFIX
 849
 850 // Create table mapping all options defined in Options.td
 851 static constexpr llvm::opt::OptTable::Info infoTable[] = {
 852 #define OPTION(...) LLVM_CONSTRUCT_OPT_INFO(__VA_ARGS__),
 853 #include "Options.inc"
 854 #undef OPTION
 855 };
 856
 857 COFFOptTable::COFFOptTable() : GenericOptTable(infoTable, true) {}
 858
 859 // Set color diagnostics according to --color-diagnostics={auto,always,never}
 860 // or --no-color-diagnostics flags.
 861 static void handleColorDiagnostics(COFFLinkerContext &ctx,
 862                                    opt::InputArgList &args) {
 863   auto *arg = args.getLastArg(OPT_color_diagnostics, OPT_color_diagnostics_eq,
 864                               OPT_no_color_diagnostics);
 865   if (!arg)
 866     return;
 867   if (arg->getOption().getID() == OPT_color_diagnostics) {
 868     ctx.e.errs().enable_colors(true);
 869   } else if (arg->getOption().getID() == OPT_no_color_diagnostics) {
 870     ctx.e.errs().enable_colors(false);
 871   } else {
 872     StringRef s = arg->getValue();
 873     if (s == "always")
 874       ctx.e.errs().enable_colors(true);
 875     else if (s == "never")
 876       ctx.e.errs().enable_colors(false);
 877     else if (s != "auto")
 878       error("unknown option: --color-diagnostics=" + s);
 879   }
 880 }
 881
 882 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &args) {
 883   if (auto *arg = args.getLastArg(OPT_rsp_quoting)) {
 884     StringRef s = arg->getValue();
 885     if (s != "windows" && s != "posix")
 886       error("invalid response file quoting: " + s);
 887     if (s == "windows")
 888       return cl::TokenizeWindowsCommandLine;
 889     return cl::TokenizeGNUCommandLine;
 890   }
 891   // The COFF linker always defaults to Windows quoting.
 892   return cl::TokenizeWindowsCommandLine;
 893 }
 894
 895 ArgParser::ArgParser(COFFLinkerContext &c) : ctx(c) {}
 896
 897 // Parses a given list of options.
 898 opt::InputArgList ArgParser::parse(ArrayRef<const char *> argv) {
 899   // Make InputArgList from string vectors.
 900   unsigned missingIndex;
 901   unsigned missingCount;
 902
 903   // We need to get the quoting style for response files before parsing all
 904   // options so we parse here before and ignore all the options but
 905   // --rsp-quoting and /lldignoreenv.
 906   // (This means --rsp-quoting can't be added through %LINK%.)
 907   opt::InputArgList args =
 908       ctx.optTable.ParseArgs(argv, missingIndex, missingCount);
 909
 910   // Expand response files (arguments in the form of @<filename>) and insert
 911   // flags from %LINK% and %_LINK_%, and then parse the argument again.
 912   SmallVector<const char *, 256> expandedArgv(argv.data(),
 913                                               argv.data() + argv.size());
 914   if (!args.hasArg(OPT_lldignoreenv))
 915     addLINK(expandedArgv);
 916   cl::ExpandResponseFiles(saver(), getQuotingStyle(args), expandedArgv);
 917   args = ctx.optTable.ParseArgs(ArrayRef(expandedArgv).drop_front(),
 918                                 missingIndex, missingCount);
 919
 920   // Print the real command line if response files are expanded.
 921   if (args.hasArg(OPT_verbose) && argv.size() != expandedArgv.size()) {
 922     std::string msg = "Command line:";
 923     for (const char *s : expandedArgv)
 924       msg += " " + std::string(s);
 925     message(msg);
 926   }
 927
 928   // Save the command line after response file expansion so we can write it to
 929   // the PDB if necessary. Mimic MSVC, which skips input files.
 930   ctx.config.argv = {argv[0]};
 931   for (opt::Arg *arg : args) {
 932     if (arg->getOption().getKind() != opt::Option::InputClass) {
 933       ctx.config.argv.emplace_back(args.getArgString(arg->getIndex()));
 934     }
 935   }
 936
 937   // Handle /WX early since it converts missing argument warnings to errors.
 938   ctx.e.fatalWarnings = args.hasFlag(OPT_WX, OPT_WX_no, false);
 939
 940   if (missingCount)
 941     fatal(Twine(args.getArgString(missingIndex)) + ": missing argument");
 942
 943   handleColorDiagnostics(ctx, args);
 944
 945   for (opt::Arg *arg : args.filtered(OPT_UNKNOWN)) {
 946     std::string nearest;
 947     if (ctx.optTable.findNearest(arg->getAsString(args), nearest) > 1)
 948       warn("ignoring unknown argument '" + arg->getAsString(args) + "'");
 949     else
 950       warn("ignoring unknown argument '" + arg->getAsString(args) +
 951            "', did you mean '" + nearest + "'");
 952   }
 953
 954   if (args.hasArg(OPT_lib))
 955     warn("ignoring /lib since it's not the first argument");
 956
 957   return args;
 958 }
 959
 960 // Tokenizes and parses a given string as command line in .drective section.
 961 ParsedDirectives ArgParser::parseDirectives(StringRef s) {
 962   ParsedDirectives result;
 963   SmallVector<const char *, 16> rest;
 964
 965   // Handle /EXPORT and /INCLUDE in a fast path. These directives can appear for
 966   // potentially every symbol in the object, so they must be handled quickly.
 967   SmallVector<StringRef, 16> tokens;
 968   cl::TokenizeWindowsCommandLineNoCopy(s, saver(), tokens);
 969   for (StringRef tok : tokens) {
 970     if (tok.starts_with_insensitive("/export:") ||
 971         tok.starts_with_insensitive("-export:"))
 972       result.exports.push_back(tok.substr(strlen("/export:")));
 973     else if (tok.starts_with_insensitive("/include:") ||
 974              tok.starts_with_insensitive("-include:"))
 975       result.includes.push_back(tok.substr(strlen("/include:")));
 976     else if (tok.starts_with_insensitive("/exclude-symbols:") ||
 977              tok.starts_with_insensitive("-exclude-symbols:"))
 978       result.excludes.push_back(tok.substr(strlen("/exclude-symbols:")));
 979     else {
 980       // Copy substrings that are not valid C strings. The tokenizer may have
 981       // already copied quoted arguments for us, so those do not need to be
 982       // copied again.
 983       bool HasNul = tok.end() != s.end() && tok.data()[tok.size()] == '\0';
 984       rest.push_back(HasNul ? tok.data() : saver().save(tok).data());
 985     }
 986   }
 987
 988   // Make InputArgList from unparsed string vectors.
 989   unsigned missingIndex;
 990   unsigned missingCount;
 991
 992   result.args = ctx.optTable.ParseArgs(rest, missingIndex, missingCount);
 993
 994   if (missingCount)
 995     fatal(Twine(result.args.getArgString(missingIndex)) + ": missing argument");
 996   for (auto *arg : result.args.filtered(OPT_UNKNOWN))
 997     warn("ignoring unknown argument: " + arg->getAsString(result.args));
 998   return result;
 999 }
1000
1001 // link.exe has an interesting feature. If LINK or _LINK_ environment
1002 // variables exist, their contents are handled as command line strings.
1003 // So you can pass extra arguments using them.
1004 void ArgParser::addLINK(SmallVector<const char *, 256> &argv) {
1005   // Concatenate LINK env and command line arguments, and then parse them.
1006   if (std::optional<std::string> s = Process::GetEnv("LINK")) {
1007     std::vector<const char *> v = tokenize(*s);
1008     argv.insert(std::next(argv.begin()), v.begin(), v.end());
1009   }
1010   if (std::optional<std::string> s = Process::GetEnv("_LINK_")) {
1011     std::vector<const char *> v = tokenize(*s);
1012     argv.insert(std::next(argv.begin()), v.begin(), v.end());
1013   }
1014 }
1015
1016 std::vector<const char *> ArgParser::tokenize(StringRef s) {
1017   SmallVector<const char *, 16> tokens;
1018   cl::TokenizeWindowsCommandLine(s, saver(), tokens);
1019   return std::vector<const char *>(tokens.begin(), tokens.end());
1020 }
1021
1022 void LinkerDriver::printHelp(const char *argv0) {
1023   ctx.optTable.printHelp(ctx.e.outs(),
1024                          (std::string(argv0) + " [options] file...").c_str(),
1025                          "LLVM Linker", false);
1026 }
1027
1028 } // namespace coff
1029 } // namespace lld