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