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 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
68static 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
91static 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
101static 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
110static 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
142static 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
164static 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
188static 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      Magic != file_magic::coff_import_library) {
196    llvm::errs() << MB.getBufferIdentifier()
197                 << ": not a COFF object, bitcode, archive, import library or "
198                    "resource file\n";
199    exit(1);
200  }
201
202  // If a user attempts to add an archive to another archive, llvm-lib doesn't
203  // handle the first archive file as a single file. Instead, it extracts all
204  // members from the archive and add them to the second archive. This beahvior
205  // is for compatibility with Microsoft's lib command.
206  if (Magic == file_magic::archive) {
207    Error Err = Error::success();
208    object::Archive Archive(MB, Err);
209    fatalOpenError(std::move(Err), MB.getBufferIdentifier());
210
211    for (auto &C : Archive.children(Err)) {
212      Expected<MemoryBufferRef> ChildMB = C.getMemoryBufferRef();
213      if (!ChildMB) {
214        handleAllErrors(ChildMB.takeError(), [&](const ErrorInfoBase &EIB) {
215          llvm::errs() << MB.getBufferIdentifier() << ": " << EIB.message()
216                       << "\n";
217        });
218        exit(1);
219      }
220
221      appendFile(Members, LibMachine, LibMachineSource, *ChildMB);
222    }
223
224    fatalOpenError(std::move(Err), MB.getBufferIdentifier());
225    return;
226  }
227
228  // Check that all input files have the same machine type.
229  // Mixing normal objects and LTO bitcode files is fine as long as they
230  // have the same machine type.
231  // Doing this here duplicates the header parsing work that writeArchive()
232  // below does, but it's not a lot of work and it's a bit awkward to do
233  // in writeArchive() which needs to support many tools, can't assume the
234  // input is COFF, and doesn't have a good way to report errors.
235  if (Magic == file_magic::coff_object || Magic == file_magic::bitcode) {
236    COFF::MachineTypes FileMachine = (Magic == file_magic::coff_object)
237                                         ? getCOFFFileMachine(MB)
238                                         : getBitcodeFileMachine(MB);
239
240    // FIXME: Once lld-link rejects multiple resource .obj files:
241    // Call convertResToCOFF() on .res files and add the resulting
242    // COFF file to the .lib output instead of adding the .res file, and remove
243    // this check. See PR42180.
244    if (FileMachine != COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
245      if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
246        LibMachine = FileMachine;
247        LibMachineSource =
248            (" (inferred from earlier file '" + MB.getBufferIdentifier() + "')")
249                .str();
250      } else if (LibMachine != FileMachine) {
251        llvm::errs() << MB.getBufferIdentifier() << ": file machine type "
252                     << machineToStr(FileMachine)
253                     << " conflicts with library machine type "
254                     << machineToStr(LibMachine) << LibMachineSource << '\n';
255        exit(1);
256      }
257    }
258  }
259
260  Members.emplace_back(MB);
261}
262
263int llvm::libDriverMain(ArrayRef<const char *> ArgsArr) {
264  BumpPtrAllocator Alloc;
265  StringSaver Saver(Alloc);
266
267  // Parse command line arguments.
268  SmallVector<const char *, 20> NewArgs(ArgsArr.begin(), ArgsArr.end());
269  cl::ExpandResponseFiles(Saver, cl::TokenizeWindowsCommandLine, NewArgs);
270  ArgsArr = NewArgs;
271
272  LibOptTable Table;
273  unsigned MissingIndex;
274  unsigned MissingCount;
275  opt::InputArgList Args =
276      Table.ParseArgs(ArgsArr.slice(1), MissingIndex, MissingCount);
277  if (MissingCount) {
278    llvm::errs() << "missing arg value for \""
279                 << Args.getArgString(MissingIndex) << "\", expected "
280                 << MissingCount
281                 << (MissingCount == 1 ? " argument.\n" : " arguments.\n");
282    return 1;
283  }
284  for (auto *Arg : Args.filtered(OPT_UNKNOWN))
285    llvm::errs() << "ignoring unknown argument: " << Arg->getAsString(Args)
286                 << "\n";
287
288  // Handle /help
289  if (Args.hasArg(OPT_help)) {
290    Table.PrintHelp(outs(), "llvm-lib [options] file...", "LLVM Lib");
291    return 0;
292  }
293
294  // If no input files and not told otherwise, silently do nothing to match
295  // lib.exe
296  if (!Args.hasArgNoClaim(OPT_INPUT) && !Args.hasArg(OPT_llvmlibempty))
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;
356  if (auto *Arg = Args.getLastArg(OPT_out)) {
357    OutputPath = Arg->getValue();
358  } else if (!Members.empty()) {
359    OutputPath = getDefaultOutputPath(Members[0]);
360  } else {
361    llvm::errs() << "no output path given, and cannot infer with no inputs\n";
362    return 1;
363  }
364  // llvm-lib uses relative paths for both regular and thin archives, unlike
365  // standard GNU ar, which only uses relative paths for thin archives and
366  // basenames for regular archives.
367  for (NewArchiveMember &Member : Members) {
368    if (sys::path::is_relative(Member.MemberName)) {
369      Expected<std::string> PathOrErr =
370          computeArchiveRelativePath(OutputPath, Member.MemberName);
371      if (PathOrErr)
372        Member.MemberName = Saver.save(*PathOrErr);
373    }
374  }
375
376  if (Error E =
377          writeArchive(OutputPath, Members,
378                       /*WriteSymtab=*/true, object::Archive::K_GNU,
379                       /*Deterministic*/ true, Args.hasArg(OPT_llvmlibthin))) {
380    handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
381      llvm::errs() << OutputPath << ": " << EI.message() << "\n";
382    });
383    return 1;
384  }
385
386  return 0;
387}
388