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#include <optional>
32
33using namespace llvm;
34
35namespace {
36
37enum {
38  OPT_INVALID = 0,
39#define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
40#include "Options.inc"
41#undef OPTION
42};
43
44#define PREFIX(NAME, VALUE)                                                    \
45  static constexpr StringLiteral NAME##_init[] = VALUE;                        \
46  static constexpr ArrayRef<StringLiteral> NAME(NAME##_init,                   \
47                                                std::size(NAME##_init) - 1);
48#include "Options.inc"
49#undef PREFIX
50
51static constexpr opt::OptTable::Info InfoTable[] = {
52#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
53  {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
54   X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
55#include "Options.inc"
56#undef OPTION
57};
58
59class LibOptTable : public opt::GenericOptTable {
60public:
61  LibOptTable() : opt::GenericOptTable(InfoTable, true) {}
62};
63}
64
65static std::string getDefaultOutputPath(const NewArchiveMember &FirstMember) {
66  SmallString<128> Val = StringRef(FirstMember.Buf->getBufferIdentifier());
67  sys::path::replace_extension(Val, ".lib");
68  return std::string(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  std::optional<std::string> EnvOpt = sys::Process::GetEnv("LIB");
83  if (!EnvOpt)
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 std::string(Path);
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 = MemoryBuffer::getFile(
119        Arg->getValue(), /*IsText=*/false, /*RequiresNullTerminator=*/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 Expected<COFF::MachineTypes> getCOFFFileMachine(MemoryBufferRef MB) {
146  std::error_code EC;
147  auto Obj = object::COFFObjectFile::create(MB);
148  if (!Obj)
149    return Obj.takeError();
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    return createStringError(inconvertibleErrorCode(),
157                             "unknown machine: " + std::to_string(Machine));
158  }
159
160  return static_cast<COFF::MachineTypes>(Machine);
161}
162
163static Expected<COFF::MachineTypes> getBitcodeFileMachine(MemoryBufferRef MB) {
164  Expected<std::string> TripleStr = getBitcodeTargetTriple(MB);
165  if (!TripleStr)
166    return TripleStr.takeError();
167
168  switch (Triple(*TripleStr).getArch()) {
169  case Triple::x86:
170    return COFF::IMAGE_FILE_MACHINE_I386;
171  case Triple::x86_64:
172    return COFF::IMAGE_FILE_MACHINE_AMD64;
173  case Triple::arm:
174    return COFF::IMAGE_FILE_MACHINE_ARMNT;
175  case Triple::aarch64:
176    return COFF::IMAGE_FILE_MACHINE_ARM64;
177  default:
178    return createStringError(inconvertibleErrorCode(),
179                             "unknown arch in target triple: " + *TripleStr);
180  }
181}
182
183static void appendFile(std::vector<NewArchiveMember> &Members,
184                       COFF::MachineTypes &LibMachine,
185                       std::string &LibMachineSource, MemoryBufferRef MB) {
186  file_magic Magic = identify_magic(MB.getBuffer());
187
188  if (Magic != file_magic::coff_object && Magic != file_magic::bitcode &&
189      Magic != file_magic::archive && Magic != file_magic::windows_resource &&
190      Magic != file_magic::coff_import_library) {
191    llvm::errs() << MB.getBufferIdentifier()
192                 << ": not a COFF object, bitcode, archive, import library or "
193                    "resource file\n";
194    exit(1);
195  }
196
197  // If a user attempts to add an archive to another archive, llvm-lib doesn't
198  // handle the first archive file as a single file. Instead, it extracts all
199  // members from the archive and add them to the second archive. This behavior
200  // is for compatibility with Microsoft's lib command.
201  if (Magic == file_magic::archive) {
202    Error Err = Error::success();
203    object::Archive Archive(MB, Err);
204    fatalOpenError(std::move(Err), MB.getBufferIdentifier());
205
206    for (auto &C : Archive.children(Err)) {
207      Expected<MemoryBufferRef> ChildMB = C.getMemoryBufferRef();
208      if (!ChildMB) {
209        handleAllErrors(ChildMB.takeError(), [&](const ErrorInfoBase &EIB) {
210          llvm::errs() << MB.getBufferIdentifier() << ": " << EIB.message()
211                       << "\n";
212        });
213        exit(1);
214      }
215
216      appendFile(Members, LibMachine, LibMachineSource, *ChildMB);
217    }
218
219    fatalOpenError(std::move(Err), MB.getBufferIdentifier());
220    return;
221  }
222
223  // Check that all input files have the same machine type.
224  // Mixing normal objects and LTO bitcode files is fine as long as they
225  // have the same machine type.
226  // Doing this here duplicates the header parsing work that writeArchive()
227  // below does, but it's not a lot of work and it's a bit awkward to do
228  // in writeArchive() which needs to support many tools, can't assume the
229  // input is COFF, and doesn't have a good way to report errors.
230  if (Magic == file_magic::coff_object || Magic == file_magic::bitcode) {
231    Expected<COFF::MachineTypes> MaybeFileMachine =
232        (Magic == file_magic::coff_object) ? getCOFFFileMachine(MB)
233                                           : getBitcodeFileMachine(MB);
234    if (!MaybeFileMachine) {
235      handleAllErrors(MaybeFileMachine.takeError(),
236                      [&](const ErrorInfoBase &EIB) {
237                        llvm::errs() << MB.getBufferIdentifier() << ": "
238                                     << EIB.message() << "\n";
239                      });
240      exit(1);
241    }
242    COFF::MachineTypes FileMachine = *MaybeFileMachine;
243
244    // FIXME: Once lld-link rejects multiple resource .obj files:
245    // Call convertResToCOFF() on .res files and add the resulting
246    // COFF file to the .lib output instead of adding the .res file, and remove
247    // this check. See PR42180.
248    if (FileMachine != COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
249      if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
250        LibMachine = FileMachine;
251        LibMachineSource =
252            (" (inferred from earlier file '" + MB.getBufferIdentifier() + "')")
253                .str();
254      } else if (LibMachine != FileMachine) {
255        llvm::errs() << MB.getBufferIdentifier() << ": file machine type "
256                     << machineToStr(FileMachine)
257                     << " conflicts with library machine type "
258                     << machineToStr(LibMachine) << LibMachineSource << '\n';
259        exit(1);
260      }
261    }
262  }
263
264  Members.emplace_back(MB);
265}
266
267int llvm::libDriverMain(ArrayRef<const char *> ArgsArr) {
268  BumpPtrAllocator Alloc;
269  StringSaver Saver(Alloc);
270
271  // Parse command line arguments.
272  SmallVector<const char *, 20> NewArgs(ArgsArr.begin(), ArgsArr.end());
273  cl::ExpandResponseFiles(Saver, cl::TokenizeWindowsCommandLine, NewArgs);
274  ArgsArr = NewArgs;
275
276  LibOptTable Table;
277  unsigned MissingIndex;
278  unsigned MissingCount;
279  opt::InputArgList Args =
280      Table.ParseArgs(ArgsArr.slice(1), MissingIndex, MissingCount);
281  if (MissingCount) {
282    llvm::errs() << "missing arg value for \""
283                 << Args.getArgString(MissingIndex) << "\", expected "
284                 << MissingCount
285                 << (MissingCount == 1 ? " argument.\n" : " arguments.\n");
286    return 1;
287  }
288  for (auto *Arg : Args.filtered(OPT_UNKNOWN))
289    llvm::errs() << "ignoring unknown argument: " << Arg->getAsString(Args)
290                 << "\n";
291
292  // Handle /help
293  if (Args.hasArg(OPT_help)) {
294    Table.printHelp(outs(), "llvm-lib [options] file...", "LLVM Lib");
295    return 0;
296  }
297
298  // Parse /ignore:
299  llvm::StringSet<> IgnoredWarnings;
300  for (auto *Arg : Args.filtered(OPT_ignore))
301    IgnoredWarnings.insert(Arg->getValue());
302
303  // If no input files and not told otherwise, silently do nothing to match
304  // lib.exe
305  if (!Args.hasArgNoClaim(OPT_INPUT) && !Args.hasArg(OPT_llvmlibempty)) {
306    if (!IgnoredWarnings.contains("emptyoutput")) {
307      llvm::errs() << "warning: no input files, not writing output file\n";
308      llvm::errs() << "         pass /llvmlibempty to write empty .lib file,\n";
309      llvm::errs() << "         pass /ignore:emptyoutput to suppress warning\n";
310      if (Args.hasFlag(OPT_WX, OPT_WX_no, false)) {
311        llvm::errs() << "treating warning as error due to /WX\n";
312        return 1;
313      }
314    }
315    return 0;
316  }
317
318  if (Args.hasArg(OPT_lst)) {
319    doList(Args);
320    return 0;
321  }
322
323  std::vector<StringRef> SearchPaths = getSearchPaths(&Args, Saver);
324
325  COFF::MachineTypes LibMachine = COFF::IMAGE_FILE_MACHINE_UNKNOWN;
326  std::string LibMachineSource;
327  if (auto *Arg = Args.getLastArg(OPT_machine)) {
328    LibMachine = getMachineType(Arg->getValue());
329    if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
330      llvm::errs() << "unknown /machine: arg " << Arg->getValue() << '\n';
331      return 1;
332    }
333    LibMachineSource =
334        std::string(" (from '/machine:") + Arg->getValue() + "' flag)";
335  }
336
337  std::vector<std::unique_ptr<MemoryBuffer>> MBs;
338  StringSet<> Seen;
339  std::vector<NewArchiveMember> Members;
340
341  // Create a NewArchiveMember for each input file.
342  for (auto *Arg : Args.filtered(OPT_INPUT)) {
343    // Find a file
344    std::string Path = findInputFile(Arg->getValue(), SearchPaths);
345    if (Path.empty()) {
346      llvm::errs() << Arg->getValue() << ": no such file or directory\n";
347      return 1;
348    }
349
350    // Input files are uniquified by pathname. If you specify the exact same
351    // path more than once, all but the first one are ignored.
352    //
353    // Note that there's a loophole in the rule; you can prepend `.\` or
354    // something like that to a path to make it look different, and they are
355    // handled as if they were different files. This behavior is compatible with
356    // Microsoft lib.exe.
357    if (!Seen.insert(Path).second)
358      continue;
359
360    // Open a file.
361    ErrorOr<std::unique_ptr<MemoryBuffer>> MOrErr = MemoryBuffer::getFile(
362        Path, /*IsText=*/false, /*RequiresNullTerminator=*/false);
363    fatalOpenError(errorCodeToError(MOrErr.getError()), Path);
364    MemoryBufferRef MBRef = (*MOrErr)->getMemBufferRef();
365
366    // Append a file.
367    appendFile(Members, LibMachine, LibMachineSource, MBRef);
368
369    // Take the ownership of the file buffer to keep the file open.
370    MBs.push_back(std::move(*MOrErr));
371  }
372
373  // Create an archive file.
374  std::string OutputPath;
375  if (auto *Arg = Args.getLastArg(OPT_out)) {
376    OutputPath = Arg->getValue();
377  } else if (!Members.empty()) {
378    OutputPath = getDefaultOutputPath(Members[0]);
379  } else {
380    llvm::errs() << "no output path given, and cannot infer with no inputs\n";
381    return 1;
382  }
383  // llvm-lib uses relative paths for both regular and thin archives, unlike
384  // standard GNU ar, which only uses relative paths for thin archives and
385  // basenames for regular archives.
386  for (NewArchiveMember &Member : Members) {
387    if (sys::path::is_relative(Member.MemberName)) {
388      Expected<std::string> PathOrErr =
389          computeArchiveRelativePath(OutputPath, Member.MemberName);
390      if (PathOrErr)
391        Member.MemberName = Saver.save(*PathOrErr);
392    }
393  }
394
395  if (Error E =
396          writeArchive(OutputPath, Members,
397                       /*WriteSymtab=*/true, object::Archive::K_GNU,
398                       /*Deterministic*/ true, Args.hasArg(OPT_llvmlibthin))) {
399    handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
400      llvm::errs() << OutputPath << ": " << EI.message() << "\n";
401    });
402    return 1;
403  }
404
405  return 0;
406}
407