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