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