xref: /llvm-project/llvm/lib/ToolDrivers/llvm-lib/LibDriver.cpp (revision 39772063f513ef24729ed9f20830e887d89459b6) 
1 //===- LibDriver.cpp - lib.exe-compatible driver --------------------------===//
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 // Defines an interface to a lib.exe-compatible driver that also understands
10 // bitcode files. Used by llvm-lib and lld-link /lib.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/ToolDrivers/llvm-lib/LibDriver.h"
15 #include "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/StringSet.h"
17 #include "llvm/BinaryFormat/COFF.h"
18 #include "llvm/BinaryFormat/Magic.h"
19 #include "llvm/Bitcode/BitcodeReader.h"
20 #include "llvm/Object/ArchiveWriter.h"
21 #include "llvm/Object/COFF.h"
22 #include "llvm/Object/WindowsMachineFlag.h"
23 #include "llvm/Option/Arg.h"
24 #include "llvm/Option/ArgList.h"
25 #include "llvm/Option/Option.h"
26 #include "llvm/Support/CommandLine.h"
27 #include "llvm/Support/Path.h"
28 #include "llvm/Support/Process.h"
29 #include "llvm/Support/StringSaver.h"
30 #include "llvm/Support/raw_ostream.h"
31 
32 using namespace llvm;
33 
34 namespace {
35 
36 enum {
37   OPT_INVALID = 0,
38 #define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
39 #include "Options.inc"
40 #undef OPTION
41 };
42 
43 #define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
44 #include "Options.inc"
45 #undef PREFIX
46 
47 static const opt::OptTable::Info InfoTable[] = {
48 #define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
49   {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
50    X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
51 #include "Options.inc"
52 #undef OPTION
53 };
54 
55 class LibOptTable : public opt::OptTable {
56 public:
57   LibOptTable() : OptTable(InfoTable, true) {}
58 };
59 
60 }
61 
62 static std::string getDefaultOutputPath(const NewArchiveMember &FirstMember) {
63   SmallString<128> Val = StringRef(FirstMember.Buf->getBufferIdentifier());
64   sys::path::replace_extension(Val, ".lib");
65   return std::string(Val.str());
66 }
67 
68 static std::vector<StringRef> getSearchPaths(opt::InputArgList *Args,
69                                              StringSaver &Saver) {
70   std::vector<StringRef> Ret;
71   // Add current directory as first item of the search path.
72   Ret.push_back("");
73 
74   // Add /libpath flags.
75   for (auto *Arg : Args->filtered(OPT_libpath))
76     Ret.push_back(Arg->getValue());
77 
78   // Add $LIB.
79   Optional<std::string> EnvOpt = sys::Process::GetEnv("LIB");
80   if (!EnvOpt.hasValue())
81     return Ret;
82   StringRef Env = Saver.save(*EnvOpt);
83   while (!Env.empty()) {
84     StringRef Path;
85     std::tie(Path, Env) = Env.split(';');
86     Ret.push_back(Path);
87   }
88   return Ret;
89 }
90 
91 static std::string findInputFile(StringRef File, ArrayRef<StringRef> Paths) {
92   for (StringRef Dir : Paths) {
93     SmallString<128> Path = Dir;
94     sys::path::append(Path, File);
95     if (sys::fs::exists(Path))
96       return std::string(Path);
97   }
98   return "";
99 }
100 
101 static void fatalOpenError(llvm::Error E, Twine File) {
102   if (!E)
103     return;
104   handleAllErrors(std::move(E), [&](const llvm::ErrorInfoBase &EIB) {
105     llvm::errs() << "error opening '" << File << "': " << EIB.message() << '\n';
106     exit(1);
107   });
108 }
109 
110 static void doList(opt::InputArgList& Args) {
111   // lib.exe prints the contents of the first archive file.
112   std::unique_ptr<MemoryBuffer> B;
113   for (auto *Arg : Args.filtered(OPT_INPUT)) {
114     // Create or open the archive object.
115     ErrorOr<std::unique_ptr<MemoryBuffer>> MaybeBuf =
116         MemoryBuffer::getFile(Arg->getValue(), -1, false);
117     fatalOpenError(errorCodeToError(MaybeBuf.getError()), Arg->getValue());
118 
119     if (identify_magic(MaybeBuf.get()->getBuffer()) == file_magic::archive) {
120       B = std::move(MaybeBuf.get());
121       break;
122     }
123   }
124 
125   // lib.exe doesn't print an error if no .lib files are passed.
126   if (!B)
127     return;
128 
129   Error Err = Error::success();
130   object::Archive Archive(B.get()->getMemBufferRef(), Err);
131   fatalOpenError(std::move(Err), B->getBufferIdentifier());
132 
133   for (auto &C : Archive.children(Err)) {
134     Expected<StringRef> NameOrErr = C.getName();
135     fatalOpenError(NameOrErr.takeError(), B->getBufferIdentifier());
136     StringRef Name = NameOrErr.get();
137     llvm::outs() << Name << '\n';
138   }
139   fatalOpenError(std::move(Err), B->getBufferIdentifier());
140 }
141 
142 static COFF::MachineTypes getCOFFFileMachine(MemoryBufferRef MB) {
143   std::error_code EC;
144   auto Obj = object::COFFObjectFile::create(MB);
145   if (!Obj) {
146     llvm::errs() << MB.getBufferIdentifier()
147                  << ": failed to open: " << Obj.takeError() << '\n';
148     exit(1);
149   }
150 
151   uint16_t Machine = (*Obj)->getMachine();
152   if (Machine != COFF::IMAGE_FILE_MACHINE_I386 &&
153       Machine != COFF::IMAGE_FILE_MACHINE_AMD64 &&
154       Machine != COFF::IMAGE_FILE_MACHINE_ARMNT &&
155       Machine != COFF::IMAGE_FILE_MACHINE_ARM64) {
156     llvm::errs() << MB.getBufferIdentifier() << ": unknown machine: " << Machine
157                  << '\n';
158     exit(1);
159   }
160 
161   return static_cast<COFF::MachineTypes>(Machine);
162 }
163 
164 static COFF::MachineTypes getBitcodeFileMachine(MemoryBufferRef MB) {
165   Expected<std::string> TripleStr = getBitcodeTargetTriple(MB);
166   if (!TripleStr) {
167     llvm::errs() << MB.getBufferIdentifier()
168                  << ": failed to get target triple from bitcode\n";
169     exit(1);
170   }
171 
172   switch (Triple(*TripleStr).getArch()) {
173   case Triple::x86:
174     return COFF::IMAGE_FILE_MACHINE_I386;
175   case Triple::x86_64:
176     return COFF::IMAGE_FILE_MACHINE_AMD64;
177   case Triple::arm:
178     return COFF::IMAGE_FILE_MACHINE_ARMNT;
179   case Triple::aarch64:
180     return COFF::IMAGE_FILE_MACHINE_ARM64;
181   default:
182     llvm::errs() << MB.getBufferIdentifier()
183                  << ": unknown arch in target triple " << *TripleStr << '\n';
184     exit(1);
185   }
186 }
187 
188 static void appendFile(std::vector<NewArchiveMember> &Members,
189                        COFF::MachineTypes &LibMachine,
190                        std::string &LibMachineSource, MemoryBufferRef MB) {
191   file_magic Magic = identify_magic(MB.getBuffer());
192 
193   if (Magic != file_magic::coff_object && Magic != file_magic::bitcode &&
194       Magic != file_magic::archive && Magic != file_magic::windows_resource) {
195     llvm::errs() << MB.getBufferIdentifier()
196                  << ": not a COFF object, bitcode, archive or resource file\n";
197     exit(1);
198   }
199 
200   // If a user attempts to add an archive to another archive, llvm-lib doesn't
201   // handle the first archive file as a single file. Instead, it extracts all
202   // members from the archive and add them to the second archive. This beahvior
203   // is for compatibility with Microsoft's lib command.
204   if (Magic == file_magic::archive) {
205     Error Err = Error::success();
206     object::Archive Archive(MB, Err);
207     fatalOpenError(std::move(Err), MB.getBufferIdentifier());
208 
209     for (auto &C : Archive.children(Err)) {
210       Expected<MemoryBufferRef> ChildMB = C.getMemoryBufferRef();
211       if (!ChildMB) {
212         handleAllErrors(ChildMB.takeError(), [&](const ErrorInfoBase &EIB) {
213           llvm::errs() << MB.getBufferIdentifier() << ": " << EIB.message()
214                        << "\n";
215         });
216         exit(1);
217       }
218 
219       appendFile(Members, LibMachine, LibMachineSource, *ChildMB);
220     }
221 
222     fatalOpenError(std::move(Err), MB.getBufferIdentifier());
223     return;
224   }
225 
226   // Check that all input files have the same machine type.
227   // Mixing normal objects and LTO bitcode files is fine as long as they
228   // have the same machine type.
229   // Doing this here duplicates the header parsing work that writeArchive()
230   // below does, but it's not a lot of work and it's a bit awkward to do
231   // in writeArchive() which needs to support many tools, can't assume the
232   // input is COFF, and doesn't have a good way to report errors.
233   if (Magic == file_magic::coff_object || Magic == file_magic::bitcode) {
234     COFF::MachineTypes FileMachine = (Magic == file_magic::coff_object)
235                                          ? getCOFFFileMachine(MB)
236                                          : getBitcodeFileMachine(MB);
237 
238     // FIXME: Once lld-link rejects multiple resource .obj files:
239     // Call convertResToCOFF() on .res files and add the resulting
240     // COFF file to the .lib output instead of adding the .res file, and remove
241     // this check. See PR42180.
242     if (FileMachine != COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
243       if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
244         LibMachine = FileMachine;
245         LibMachineSource =
246             (" (inferred from earlier file '" + MB.getBufferIdentifier() + "')")
247                 .str();
248       } else if (LibMachine != FileMachine) {
249         llvm::errs() << MB.getBufferIdentifier() << ": file machine type "
250                      << machineToStr(FileMachine)
251                      << " conflicts with library machine type "
252                      << machineToStr(LibMachine) << LibMachineSource << '\n';
253         exit(1);
254       }
255     }
256   }
257 
258   Members.emplace_back(MB);
259 }
260 
261 int llvm::libDriverMain(ArrayRef<const char *> ArgsArr) {
262   BumpPtrAllocator Alloc;
263   StringSaver Saver(Alloc);
264 
265   // Parse command line arguments.
266   SmallVector<const char *, 20> NewArgs(ArgsArr.begin(), ArgsArr.end());
267   cl::ExpandResponseFiles(Saver, cl::TokenizeWindowsCommandLine, NewArgs);
268   ArgsArr = NewArgs;
269 
270   LibOptTable Table;
271   unsigned MissingIndex;
272   unsigned MissingCount;
273   opt::InputArgList Args =
274       Table.ParseArgs(ArgsArr.slice(1), MissingIndex, MissingCount);
275   if (MissingCount) {
276     llvm::errs() << "missing arg value for \""
277                  << Args.getArgString(MissingIndex) << "\", expected "
278                  << MissingCount
279                  << (MissingCount == 1 ? " argument.\n" : " arguments.\n");
280     return 1;
281   }
282   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
283     llvm::errs() << "ignoring unknown argument: " << Arg->getAsString(Args)
284                  << "\n";
285 
286   // Handle /help
287   if (Args.hasArg(OPT_help)) {
288     Table.PrintHelp(outs(), "llvm-lib [options] file...", "LLVM Lib");
289     return 0;
290   }
291 
292   // If no input files and not told otherwise, silently do nothing to match
293   // lib.exe
294   if (!Args.hasArgNoClaim(OPT_INPUT) && !Args.hasArg(OPT_llvmlibempty))
295     return 0;
296 
297   if (Args.hasArg(OPT_lst)) {
298     doList(Args);
299     return 0;
300   }
301 
302   std::vector<StringRef> SearchPaths = getSearchPaths(&Args, Saver);
303 
304   COFF::MachineTypes LibMachine = COFF::IMAGE_FILE_MACHINE_UNKNOWN;
305   std::string LibMachineSource;
306   if (auto *Arg = Args.getLastArg(OPT_machine)) {
307     LibMachine = getMachineType(Arg->getValue());
308     if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
309       llvm::errs() << "unknown /machine: arg " << Arg->getValue() << '\n';
310       return 1;
311     }
312     LibMachineSource =
313         std::string(" (from '/machine:") + Arg->getValue() + "' flag)";
314   }
315 
316   std::vector<std::unique_ptr<MemoryBuffer>> MBs;
317   StringSet<> Seen;
318   std::vector<NewArchiveMember> Members;
319 
320   // Create a NewArchiveMember for each input file.
321   for (auto *Arg : Args.filtered(OPT_INPUT)) {
322     // Find a file
323     std::string Path = findInputFile(Arg->getValue(), SearchPaths);
324     if (Path.empty()) {
325       llvm::errs() << Arg->getValue() << ": no such file or directory\n";
326       return 1;
327     }
328 
329     // Input files are uniquified by pathname. If you specify the exact same
330     // path more than once, all but the first one are ignored.
331     //
332     // Note that there's a loophole in the rule; you can prepend `.\` or
333     // something like that to a path to make it look different, and they are
334     // handled as if they were different files. This behavior is compatible with
335     // Microsoft lib.exe.
336     if (!Seen.insert(Path).second)
337       continue;
338 
339     // Open a file.
340     ErrorOr<std::unique_ptr<MemoryBuffer>> MOrErr =
341         MemoryBuffer::getFile(Path, -1, false);
342     fatalOpenError(errorCodeToError(MOrErr.getError()), Path);
343     MemoryBufferRef MBRef = (*MOrErr)->getMemBufferRef();
344 
345     // Append a file.
346     appendFile(Members, LibMachine, LibMachineSource, MBRef);
347 
348     // Take the ownership of the file buffer to keep the file open.
349     MBs.push_back(std::move(*MOrErr));
350   }
351 
352   // Create an archive file.
353   std::string OutputPath;
354   if (auto *Arg = Args.getLastArg(OPT_out)) {
355     OutputPath = Arg->getValue();
356   } else if (!Members.empty()) {
357     OutputPath = getDefaultOutputPath(Members[0]);
358   } else {
359     llvm::errs() << "no output path given, and cannot infer with no inputs\n";
360     return 1;
361   }
362   // llvm-lib uses relative paths for both regular and thin archives, unlike
363   // standard GNU ar, which only uses relative paths for thin archives and
364   // basenames for regular archives.
365   for (NewArchiveMember &Member : Members) {
366     if (sys::path::is_relative(Member.MemberName)) {
367       Expected<std::string> PathOrErr =
368           computeArchiveRelativePath(OutputPath, Member.MemberName);
369       if (PathOrErr)
370         Member.MemberName = Saver.save(*PathOrErr);
371     }
372   }
373 
374   if (Error E =
375           writeArchive(OutputPath, Members,
376                        /*WriteSymtab=*/true, object::Archive::K_GNU,
377                        /*Deterministic*/ true, Args.hasArg(OPT_llvmlibthin))) {
378     handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
379       llvm::errs() << OutputPath << ": " << EI.message() << "\n";
380     });
381     return 1;
382   }
383 
384   return 0;
385 }
386