1 //===- DriverUtils.cpp ----------------------------------------------------===//
2 //
3 //                             The LLVM Linker
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains utility functions for the driver. Because there
11 // are so many small functions, we created this separate file to make
12 // Driver.cpp less cluttered.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "Config.h"
17 #include "Driver.h"
18 #include "Error.h"
19 #include "Memory.h"
20 #include "Symbols.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/StringSwitch.h"
23 #include "llvm/BinaryFormat/COFF.h"
24 #include "llvm/Object/COFF.h"
25 #include "llvm/Object/WindowsResource.h"
26 #include "llvm/Option/Arg.h"
27 #include "llvm/Option/ArgList.h"
28 #include "llvm/Option/Option.h"
29 #include "llvm/Support/CommandLine.h"
30 #include "llvm/Support/FileUtilities.h"
31 #include "llvm/Support/MathExtras.h"
32 #include "llvm/Support/Process.h"
33 #include "llvm/Support/Program.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include "llvm/WindowsManifest/WindowsManifestMerger.h"
36 #include <memory>
37 
38 using namespace llvm::COFF;
39 using namespace llvm;
40 using llvm::sys::Process;
41 
42 namespace lld {
43 namespace coff {
44 namespace {
45 
46 const uint16_t SUBLANG_ENGLISH_US = 0x0409;
47 const uint16_t RT_MANIFEST = 24;
48 
49 class Executor {
50 public:
51   explicit Executor(StringRef S) : Prog(Saver.save(S)) {}
52   void add(StringRef S) { Args.push_back(Saver.save(S)); }
53   void add(std::string &S) { Args.push_back(Saver.save(S)); }
54   void add(Twine S) { Args.push_back(Saver.save(S)); }
55   void add(const char *S) { Args.push_back(Saver.save(S)); }
56 
57   void run() {
58     ErrorOr<std::string> ExeOrErr = sys::findProgramByName(Prog);
59     if (auto EC = ExeOrErr.getError())
60       fatal(EC, "unable to find " + Prog + " in PATH");
61     StringRef Exe = Saver.save(*ExeOrErr);
62     Args.insert(Args.begin(), Exe);
63 
64     std::vector<const char *> Vec;
65     for (StringRef S : Args)
66       Vec.push_back(S.data());
67     Vec.push_back(nullptr);
68 
69     if (sys::ExecuteAndWait(Args[0], Vec.data()) != 0)
70       fatal("ExecuteAndWait failed: " +
71             llvm::join(Args.begin(), Args.end(), " "));
72   }
73 
74 private:
75   StringRef Prog;
76   std::vector<StringRef> Args;
77 };
78 
79 } // anonymous namespace
80 
81 // Returns /machine's value.
82 MachineTypes getMachineType(StringRef S) {
83   MachineTypes MT = StringSwitch<MachineTypes>(S.lower())
84                         .Cases("x64", "amd64", AMD64)
85                         .Cases("x86", "i386", I386)
86                         .Case("arm", ARMNT)
87                         .Case("arm64", ARM64)
88                         .Default(IMAGE_FILE_MACHINE_UNKNOWN);
89   if (MT != IMAGE_FILE_MACHINE_UNKNOWN)
90     return MT;
91   fatal("unknown /machine argument: " + S);
92 }
93 
94 StringRef machineToStr(MachineTypes MT) {
95   switch (MT) {
96   case ARMNT:
97     return "arm";
98   case ARM64:
99     return "arm64";
100   case AMD64:
101     return "x64";
102   case I386:
103     return "x86";
104   default:
105     llvm_unreachable("unknown machine type");
106   }
107 }
108 
109 // Parses a string in the form of "<integer>[,<integer>]".
110 void parseNumbers(StringRef Arg, uint64_t *Addr, uint64_t *Size) {
111   StringRef S1, S2;
112   std::tie(S1, S2) = Arg.split(',');
113   if (S1.getAsInteger(0, *Addr))
114     fatal("invalid number: " + S1);
115   if (Size && !S2.empty() && S2.getAsInteger(0, *Size))
116     fatal("invalid number: " + S2);
117 }
118 
119 // Parses a string in the form of "<integer>[.<integer>]".
120 // If second number is not present, Minor is set to 0.
121 void parseVersion(StringRef Arg, uint32_t *Major, uint32_t *Minor) {
122   StringRef S1, S2;
123   std::tie(S1, S2) = Arg.split('.');
124   if (S1.getAsInteger(0, *Major))
125     fatal("invalid number: " + S1);
126   *Minor = 0;
127   if (!S2.empty() && S2.getAsInteger(0, *Minor))
128     fatal("invalid number: " + S2);
129 }
130 
131 // Parses a string in the form of "<subsystem>[,<integer>[.<integer>]]".
132 void parseSubsystem(StringRef Arg, WindowsSubsystem *Sys, uint32_t *Major,
133                     uint32_t *Minor) {
134   StringRef SysStr, Ver;
135   std::tie(SysStr, Ver) = Arg.split(',');
136   *Sys = StringSwitch<WindowsSubsystem>(SysStr.lower())
137     .Case("boot_application", IMAGE_SUBSYSTEM_WINDOWS_BOOT_APPLICATION)
138     .Case("console", IMAGE_SUBSYSTEM_WINDOWS_CUI)
139     .Case("efi_application", IMAGE_SUBSYSTEM_EFI_APPLICATION)
140     .Case("efi_boot_service_driver", IMAGE_SUBSYSTEM_EFI_BOOT_SERVICE_DRIVER)
141     .Case("efi_rom", IMAGE_SUBSYSTEM_EFI_ROM)
142     .Case("efi_runtime_driver", IMAGE_SUBSYSTEM_EFI_RUNTIME_DRIVER)
143     .Case("native", IMAGE_SUBSYSTEM_NATIVE)
144     .Case("posix", IMAGE_SUBSYSTEM_POSIX_CUI)
145     .Case("windows", IMAGE_SUBSYSTEM_WINDOWS_GUI)
146     .Default(IMAGE_SUBSYSTEM_UNKNOWN);
147   if (*Sys == IMAGE_SUBSYSTEM_UNKNOWN)
148     fatal("unknown subsystem: " + SysStr);
149   if (!Ver.empty())
150     parseVersion(Ver, Major, Minor);
151 }
152 
153 // Parse a string of the form of "<from>=<to>".
154 // Results are directly written to Config.
155 void parseAlternateName(StringRef S) {
156   StringRef From, To;
157   std::tie(From, To) = S.split('=');
158   if (From.empty() || To.empty())
159     fatal("/alternatename: invalid argument: " + S);
160   auto It = Config->AlternateNames.find(From);
161   if (It != Config->AlternateNames.end() && It->second != To)
162     fatal("/alternatename: conflicts: " + S);
163   Config->AlternateNames.insert(It, std::make_pair(From, To));
164 }
165 
166 // Parse a string of the form of "<from>=<to>".
167 // Results are directly written to Config.
168 void parseMerge(StringRef S) {
169   StringRef From, To;
170   std::tie(From, To) = S.split('=');
171   if (From.empty() || To.empty())
172     fatal("/merge: invalid argument: " + S);
173   auto Pair = Config->Merge.insert(std::make_pair(From, To));
174   bool Inserted = Pair.second;
175   if (!Inserted) {
176     StringRef Existing = Pair.first->second;
177     if (Existing != To)
178       warn(S + ": already merged into " + Existing);
179   }
180 }
181 
182 static uint32_t parseSectionAttributes(StringRef S) {
183   uint32_t Ret = 0;
184   for (char C : S.lower()) {
185     switch (C) {
186     case 'd':
187       Ret |= IMAGE_SCN_MEM_DISCARDABLE;
188       break;
189     case 'e':
190       Ret |= IMAGE_SCN_MEM_EXECUTE;
191       break;
192     case 'k':
193       Ret |= IMAGE_SCN_MEM_NOT_CACHED;
194       break;
195     case 'p':
196       Ret |= IMAGE_SCN_MEM_NOT_PAGED;
197       break;
198     case 'r':
199       Ret |= IMAGE_SCN_MEM_READ;
200       break;
201     case 's':
202       Ret |= IMAGE_SCN_MEM_SHARED;
203       break;
204     case 'w':
205       Ret |= IMAGE_SCN_MEM_WRITE;
206       break;
207     default:
208       fatal("/section: invalid argument: " + S);
209     }
210   }
211   return Ret;
212 }
213 
214 // Parses /section option argument.
215 void parseSection(StringRef S) {
216   StringRef Name, Attrs;
217   std::tie(Name, Attrs) = S.split(',');
218   if (Name.empty() || Attrs.empty())
219     fatal("/section: invalid argument: " + S);
220   Config->Section[Name] = parseSectionAttributes(Attrs);
221 }
222 
223 // Parses /aligncomm option argument.
224 void parseAligncomm(StringRef S) {
225   StringRef Name, Align;
226   std::tie(Name, Align) = S.split(',');
227   if (Name.empty() || Align.empty()) {
228     error("/aligncomm: invalid argument: " + S);
229     return;
230   }
231   int V;
232   if (Align.getAsInteger(0, V)) {
233     error("/aligncomm: invalid argument: " + S);
234     return;
235   }
236   Config->AlignComm[Name] = std::max(Config->AlignComm[Name], 1 << V);
237 }
238 
239 // Parses a string in the form of "EMBED[,=<integer>]|NO".
240 // Results are directly written to Config.
241 void parseManifest(StringRef Arg) {
242   if (Arg.equals_lower("no")) {
243     Config->Manifest = Configuration::No;
244     return;
245   }
246   if (!Arg.startswith_lower("embed"))
247     fatal("invalid option " + Arg);
248   Config->Manifest = Configuration::Embed;
249   Arg = Arg.substr(strlen("embed"));
250   if (Arg.empty())
251     return;
252   if (!Arg.startswith_lower(",id="))
253     fatal("invalid option " + Arg);
254   Arg = Arg.substr(strlen(",id="));
255   if (Arg.getAsInteger(0, Config->ManifestID))
256     fatal("invalid option " + Arg);
257 }
258 
259 // Parses a string in the form of "level=<string>|uiAccess=<string>|NO".
260 // Results are directly written to Config.
261 void parseManifestUAC(StringRef Arg) {
262   if (Arg.equals_lower("no")) {
263     Config->ManifestUAC = false;
264     return;
265   }
266   for (;;) {
267     Arg = Arg.ltrim();
268     if (Arg.empty())
269       return;
270     if (Arg.startswith_lower("level=")) {
271       Arg = Arg.substr(strlen("level="));
272       std::tie(Config->ManifestLevel, Arg) = Arg.split(" ");
273       continue;
274     }
275     if (Arg.startswith_lower("uiaccess=")) {
276       Arg = Arg.substr(strlen("uiaccess="));
277       std::tie(Config->ManifestUIAccess, Arg) = Arg.split(" ");
278       continue;
279     }
280     fatal("invalid option " + Arg);
281   }
282 }
283 
284 // An RAII temporary file class that automatically removes a temporary file.
285 namespace {
286 class TemporaryFile {
287 public:
288   TemporaryFile(StringRef Prefix, StringRef Extn, StringRef Contents = "") {
289     SmallString<128> S;
290     if (auto EC = sys::fs::createTemporaryFile("lld-" + Prefix, Extn, S))
291       fatal(EC, "cannot create a temporary file");
292     Path = S.str();
293 
294     if (!Contents.empty()) {
295       std::error_code EC;
296       raw_fd_ostream OS(Path, EC, sys::fs::F_None);
297       if (EC)
298         fatal(EC, "failed to open " + Path);
299       OS << Contents;
300     }
301   }
302 
303   TemporaryFile(TemporaryFile &&Obj) {
304     std::swap(Path, Obj.Path);
305   }
306 
307   ~TemporaryFile() {
308     if (Path.empty())
309       return;
310     if (sys::fs::remove(Path))
311       fatal("failed to remove " + Path);
312   }
313 
314   // Returns a memory buffer of this temporary file.
315   // Note that this function does not leave the file open,
316   // so it is safe to remove the file immediately after this function
317   // is called (you cannot remove an opened file on Windows.)
318   std::unique_ptr<MemoryBuffer> getMemoryBuffer() {
319     // IsVolatileSize=true forces MemoryBuffer to not use mmap().
320     return check(MemoryBuffer::getFile(Path, /*FileSize=*/-1,
321                                        /*RequiresNullTerminator=*/false,
322                                        /*IsVolatileSize=*/true),
323                  "could not open " + Path);
324   }
325 
326   std::string Path;
327 };
328 }
329 
330 static std::string createDefaultXml() {
331   std::string Ret;
332   raw_string_ostream OS(Ret);
333 
334   // Emit the XML. Note that we do *not* verify that the XML attributes are
335   // syntactically correct. This is intentional for link.exe compatibility.
336   OS << "<?xml version=\"1.0\" standalone=\"yes\"?>\n"
337      << "<assembly xmlns=\"urn:schemas-microsoft-com:asm.v1\"\n"
338      << "          manifestVersion=\"1.0\">\n";
339   if (Config->ManifestUAC) {
340     OS << "  <trustInfo>\n"
341        << "    <security>\n"
342        << "      <requestedPrivileges>\n"
343        << "         <requestedExecutionLevel level=" << Config->ManifestLevel
344        << " uiAccess=" << Config->ManifestUIAccess << "/>\n"
345        << "      </requestedPrivileges>\n"
346        << "    </security>\n"
347        << "  </trustInfo>\n";
348   }
349   if (!Config->ManifestDependency.empty()) {
350     OS << "  <dependency>\n"
351        << "    <dependentAssembly>\n"
352        << "      <assemblyIdentity " << Config->ManifestDependency << " />\n"
353        << "    </dependentAssembly>\n"
354        << "  </dependency>\n";
355   }
356   OS << "</assembly>\n";
357   return OS.str();
358 }
359 
360 static std::string createManifestXmlWithInternalMt(StringRef DefaultXml) {
361   std::unique_ptr<MemoryBuffer> DefaultXmlCopy =
362       MemoryBuffer::getMemBufferCopy(DefaultXml);
363 
364   windows_manifest::WindowsManifestMerger Merger;
365   if (auto E = Merger.merge(*DefaultXmlCopy.get()))
366     fatal(E, "internal manifest tool failed on default xml");
367 
368   for (StringRef Filename : Config->ManifestInput) {
369     std::unique_ptr<MemoryBuffer> Manifest =
370         check(MemoryBuffer::getFile(Filename));
371     if (auto E = Merger.merge(*Manifest.get()))
372       fatal(E, "internal manifest tool failed on file " + Filename);
373   }
374 
375   return Merger.getMergedManifest().get()->getBuffer();
376 }
377 
378 static std::string createManifestXmlWithExternalMt(StringRef DefaultXml) {
379   // Create the default manifest file as a temporary file.
380   TemporaryFile Default("defaultxml", "manifest");
381   std::error_code EC;
382   raw_fd_ostream OS(Default.Path, EC, sys::fs::F_Text);
383   if (EC)
384     fatal(EC, "failed to open " + Default.Path);
385   OS << DefaultXml;
386   OS.close();
387 
388   // Merge user-supplied manifests if they are given.  Since libxml2 is not
389   // enabled, we must shell out to Microsoft's mt.exe tool.
390   TemporaryFile User("user", "manifest");
391 
392   Executor E("mt.exe");
393   E.add("/manifest");
394   E.add(Default.Path);
395   for (StringRef Filename : Config->ManifestInput) {
396     E.add("/manifest");
397     E.add(Filename);
398   }
399   E.add("/nologo");
400   E.add("/out:" + StringRef(User.Path));
401   E.run();
402 
403   return check(MemoryBuffer::getFile(User.Path), "could not open " + User.Path)
404       .get()
405       ->getBuffer();
406 }
407 
408 static std::string createManifestXml() {
409   std::string DefaultXml = createDefaultXml();
410   if (Config->ManifestInput.empty())
411     return DefaultXml;
412 
413   if (windows_manifest::isAvailable())
414     return createManifestXmlWithInternalMt(DefaultXml);
415 
416   return createManifestXmlWithExternalMt(DefaultXml);
417 }
418 
419 static std::unique_ptr<MemoryBuffer>
420 createMemoryBufferForManifestRes(size_t ManifestSize) {
421   size_t ResSize = alignTo(
422       object::WIN_RES_MAGIC_SIZE + object::WIN_RES_NULL_ENTRY_SIZE +
423           sizeof(object::WinResHeaderPrefix) + sizeof(object::WinResIDs) +
424           sizeof(object::WinResHeaderSuffix) + ManifestSize,
425       object::WIN_RES_DATA_ALIGNMENT);
426   return MemoryBuffer::getNewMemBuffer(ResSize);
427 }
428 
429 static void writeResFileHeader(char *&Buf) {
430   memcpy(Buf, COFF::WinResMagic, sizeof(COFF::WinResMagic));
431   Buf += sizeof(COFF::WinResMagic);
432   memset(Buf, 0, object::WIN_RES_NULL_ENTRY_SIZE);
433   Buf += object::WIN_RES_NULL_ENTRY_SIZE;
434 }
435 
436 static void writeResEntryHeader(char *&Buf, size_t ManifestSize) {
437   // Write the prefix.
438   auto *Prefix = reinterpret_cast<object::WinResHeaderPrefix *>(Buf);
439   Prefix->DataSize = ManifestSize;
440   Prefix->HeaderSize = sizeof(object::WinResHeaderPrefix) +
441                        sizeof(object::WinResIDs) +
442                        sizeof(object::WinResHeaderSuffix);
443   Buf += sizeof(object::WinResHeaderPrefix);
444 
445   // Write the Type/Name IDs.
446   auto *IDs = reinterpret_cast<object::WinResIDs *>(Buf);
447   IDs->setType(RT_MANIFEST);
448   IDs->setName(Config->ManifestID);
449   Buf += sizeof(object::WinResIDs);
450 
451   // Write the suffix.
452   auto *Suffix = reinterpret_cast<object::WinResHeaderSuffix *>(Buf);
453   Suffix->DataVersion = 0;
454   Suffix->MemoryFlags = object::WIN_RES_PURE_MOVEABLE;
455   Suffix->Language = SUBLANG_ENGLISH_US;
456   Suffix->Version = 0;
457   Suffix->Characteristics = 0;
458   Buf += sizeof(object::WinResHeaderSuffix);
459 }
460 
461 // Create a resource file containing a manifest XML.
462 std::unique_ptr<MemoryBuffer> createManifestRes() {
463   std::string Manifest = createManifestXml();
464 
465   std::unique_ptr<MemoryBuffer> Res =
466       createMemoryBufferForManifestRes(Manifest.size());
467 
468   char *Buf = const_cast<char *>(Res->getBufferStart());
469   writeResFileHeader(Buf);
470   writeResEntryHeader(Buf, Manifest.size());
471 
472   // Copy the manifest data into the .res file.
473   std::copy(Manifest.begin(), Manifest.end(), Buf);
474   return Res;
475 }
476 
477 void createSideBySideManifest() {
478   std::string Path = Config->ManifestFile;
479   if (Path == "")
480     Path = Config->OutputFile + ".manifest";
481   std::error_code EC;
482   raw_fd_ostream Out(Path, EC, sys::fs::F_Text);
483   if (EC)
484     fatal(EC, "failed to create manifest");
485   Out << createManifestXml();
486 }
487 
488 // Parse a string in the form of
489 // "<name>[=<internalname>][,@ordinal[,NONAME]][,DATA][,PRIVATE]"
490 // or "<name>=<dllname>.<name>".
491 // Used for parsing /export arguments.
492 Export parseExport(StringRef Arg) {
493   Export E;
494   StringRef Rest;
495   std::tie(E.Name, Rest) = Arg.split(",");
496   if (E.Name.empty())
497     goto err;
498 
499   if (E.Name.contains('=')) {
500     StringRef X, Y;
501     std::tie(X, Y) = E.Name.split("=");
502 
503     // If "<name>=<dllname>.<name>".
504     if (Y.contains(".")) {
505       E.Name = X;
506       E.ForwardTo = Y;
507       return E;
508     }
509 
510     E.ExtName = X;
511     E.Name = Y;
512     if (E.Name.empty())
513       goto err;
514   }
515 
516   // If "<name>=<internalname>[,@ordinal[,NONAME]][,DATA][,PRIVATE]"
517   while (!Rest.empty()) {
518     StringRef Tok;
519     std::tie(Tok, Rest) = Rest.split(",");
520     if (Tok.equals_lower("noname")) {
521       if (E.Ordinal == 0)
522         goto err;
523       E.Noname = true;
524       continue;
525     }
526     if (Tok.equals_lower("data")) {
527       E.Data = true;
528       continue;
529     }
530     if (Tok.equals_lower("constant")) {
531       E.Constant = true;
532       continue;
533     }
534     if (Tok.equals_lower("private")) {
535       E.Private = true;
536       continue;
537     }
538     if (Tok.startswith("@")) {
539       int32_t Ord;
540       if (Tok.substr(1).getAsInteger(0, Ord))
541         goto err;
542       if (Ord <= 0 || 65535 < Ord)
543         goto err;
544       E.Ordinal = Ord;
545       continue;
546     }
547     goto err;
548   }
549   return E;
550 
551 err:
552   fatal("invalid /export: " + Arg);
553 }
554 
555 static StringRef undecorate(StringRef Sym) {
556   if (Config->Machine != I386)
557     return Sym;
558   return Sym.startswith("_") ? Sym.substr(1) : Sym;
559 }
560 
561 // Performs error checking on all /export arguments.
562 // It also sets ordinals.
563 void fixupExports() {
564   // Symbol ordinals must be unique.
565   std::set<uint16_t> Ords;
566   for (Export &E : Config->Exports) {
567     if (E.Ordinal == 0)
568       continue;
569     if (!Ords.insert(E.Ordinal).second)
570       fatal("duplicate export ordinal: " + E.Name);
571   }
572 
573   for (Export &E : Config->Exports) {
574     SymbolBody *Sym = E.Sym;
575     if (!E.ForwardTo.empty() || !Sym) {
576       E.SymbolName = E.Name;
577     } else {
578       if (auto *U = dyn_cast<Undefined>(Sym))
579         if (U->WeakAlias)
580           Sym = U->WeakAlias;
581       E.SymbolName = Sym->getName();
582     }
583   }
584 
585   for (Export &E : Config->Exports) {
586     if (!E.ForwardTo.empty()) {
587       E.ExportName = undecorate(E.Name);
588     } else {
589       E.ExportName = undecorate(E.ExtName.empty() ? E.Name : E.ExtName);
590     }
591   }
592 
593   // Uniquefy by name.
594   std::map<StringRef, Export *> Map;
595   std::vector<Export> V;
596   for (Export &E : Config->Exports) {
597     auto Pair = Map.insert(std::make_pair(E.ExportName, &E));
598     bool Inserted = Pair.second;
599     if (Inserted) {
600       V.push_back(E);
601       continue;
602     }
603     Export *Existing = Pair.first->second;
604     if (E == *Existing || E.Name != Existing->Name)
605       continue;
606     warn("duplicate /export option: " + E.Name);
607   }
608   Config->Exports = std::move(V);
609 
610   // Sort by name.
611   std::sort(Config->Exports.begin(), Config->Exports.end(),
612             [](const Export &A, const Export &B) {
613               return A.ExportName < B.ExportName;
614             });
615 }
616 
617 void assignExportOrdinals() {
618   // Assign unique ordinals if default (= 0).
619   uint16_t Max = 0;
620   for (Export &E : Config->Exports)
621     Max = std::max(Max, E.Ordinal);
622   for (Export &E : Config->Exports)
623     if (E.Ordinal == 0)
624       E.Ordinal = ++Max;
625 }
626 
627 // Parses a string in the form of "key=value" and check
628 // if value matches previous values for the same key.
629 void checkFailIfMismatch(StringRef Arg) {
630   StringRef K, V;
631   std::tie(K, V) = Arg.split('=');
632   if (K.empty() || V.empty())
633     fatal("/failifmismatch: invalid argument: " + Arg);
634   StringRef Existing = Config->MustMatch[K];
635   if (!Existing.empty() && V != Existing)
636     fatal("/failifmismatch: mismatch detected: " + Existing + " and " + V +
637           " for key " + K);
638   Config->MustMatch[K] = V;
639 }
640 
641 // Convert Windows resource files (.res files) to a .obj file
642 // using cvtres.exe.
643 std::unique_ptr<MemoryBuffer>
644 convertResToCOFF(const std::vector<MemoryBufferRef> &MBs) {
645   object::WindowsResourceParser Parser;
646 
647   for (MemoryBufferRef MB : MBs) {
648     std::unique_ptr<object::Binary> Bin = check(object::createBinary(MB));
649     object::WindowsResource *RF = dyn_cast<object::WindowsResource>(Bin.get());
650     if (!RF)
651       fatal("cannot compile non-resource file as resource");
652     if (auto EC = Parser.parse(RF))
653       fatal(EC, "failed to parse .res file");
654   }
655 
656   Expected<std::unique_ptr<MemoryBuffer>> E =
657       llvm::object::writeWindowsResourceCOFF(Config->Machine, Parser);
658   if (!E)
659     fatal(errorToErrorCode(E.takeError()), "failed to write .res to COFF");
660   return std::move(E.get());
661 }
662 
663 // Run MSVC link.exe for given in-memory object files.
664 // Command line options are copied from those given to LLD.
665 // This is for the /msvclto option.
666 void runMSVCLinker(std::string Rsp, ArrayRef<StringRef> Objects) {
667   // Write the in-memory object files to disk.
668   std::vector<TemporaryFile> Temps;
669   for (StringRef S : Objects) {
670     Temps.emplace_back("lto", "obj", S);
671     Rsp += quote(Temps.back().Path) + "\n";
672   }
673 
674   log("link.exe " + Rsp);
675 
676   // Run MSVC link.exe.
677   Temps.emplace_back("lto", "rsp", Rsp);
678   Executor E("link.exe");
679   E.add(Twine("@" + Temps.back().Path));
680   E.run();
681 }
682 
683 // Create OptTable
684 
685 // Create prefix string literals used in Options.td
686 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
687 #include "Options.inc"
688 #undef PREFIX
689 
690 // Create table mapping all options defined in Options.td
691 static const llvm::opt::OptTable::Info InfoTable[] = {
692 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
693   {X1, X2, X10,         X11,         OPT_##ID, llvm::opt::Option::KIND##Class, \
694    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
695 #include "Options.inc"
696 #undef OPTION
697 };
698 
699 COFFOptTable::COFFOptTable() : OptTable(InfoTable, true) {}
700 
701 static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
702   if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
703     StringRef S = Arg->getValue();
704     if (S != "windows" && S != "posix")
705       error("invalid response file quoting: " + S);
706     if (S == "windows")
707       return cl::TokenizeWindowsCommandLine;
708     return cl::TokenizeGNUCommandLine;
709   }
710   // The COFF linker always defaults to Windows quoting.
711   return cl::TokenizeWindowsCommandLine;
712 }
713 
714 // Parses a given list of options.
715 opt::InputArgList ArgParser::parse(ArrayRef<const char *> Argv) {
716   // Make InputArgList from string vectors.
717   unsigned MissingIndex;
718   unsigned MissingCount;
719   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
720 
721   // We need to get the quoting style for response files before parsing all
722   // options so we parse here before and ignore all the options but
723   // --rsp-quoting.
724   opt::InputArgList Args = Table.ParseArgs(Vec, MissingIndex, MissingCount);
725 
726   // Expand response files (arguments in the form of @<filename>)
727   // and then parse the argument again.
728   cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);
729   Args = Table.ParseArgs(Vec, MissingIndex, MissingCount);
730 
731   // Print the real command line if response files are expanded.
732   if (Args.hasArg(OPT_verbose) && Argv.size() != Vec.size()) {
733     std::string Msg = "Command line:";
734     for (const char *S : Vec)
735       Msg += " " + std::string(S);
736     message(Msg);
737   }
738 
739   if (MissingCount)
740     fatal(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
741   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
742     warn("ignoring unknown argument: " + Arg->getSpelling());
743   return Args;
744 }
745 
746 // link.exe has an interesting feature. If LINK or _LINK_ environment
747 // variables exist, their contents are handled as command line strings.
748 // So you can pass extra arguments using them.
749 opt::InputArgList ArgParser::parseLINK(std::vector<const char *> Argv) {
750   // Concatenate LINK env and command line arguments, and then parse them.
751   if (Optional<std::string> S = Process::GetEnv("LINK")) {
752     std::vector<const char *> V = tokenize(*S);
753     Argv.insert(Argv.begin(), V.begin(), V.end());
754   }
755   if (Optional<std::string> S = Process::GetEnv("_LINK_")) {
756     std::vector<const char *> V = tokenize(*S);
757     Argv.insert(Argv.begin(), V.begin(), V.end());
758   }
759   return parse(Argv);
760 }
761 
762 std::vector<const char *> ArgParser::tokenize(StringRef S) {
763   SmallVector<const char *, 16> Tokens;
764   cl::TokenizeWindowsCommandLine(S, Saver, Tokens);
765   return std::vector<const char *>(Tokens.begin(), Tokens.end());
766 }
767 
768 void printHelp(const char *Argv0) {
769   COFFOptTable Table;
770   Table.PrintHelp(outs(), Argv0, "LLVM Linker", false);
771 }
772 
773 } // namespace coff
774 } // namespace lld
775