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