LibDriver.cpp

Go to the documentation of this file.

//===- LibDriver.cpp - lib.exe-compatible driver --------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Defines an interface to a lib.exe-compatible driver that also understands
// bitcode files. Used by llvm-lib and lld-link /lib.
//
//===----------------------------------------------------------------------===//
 
#include "llvm/ToolDrivers/llvm-lib/LibDriver.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/Magic.h"
#include "llvm/Bitcode/BitcodeReader.h"
#include "llvm/Object/ArchiveWriter.h"
#include "llvm/Object/COFF.h"
#include "llvm/Object/COFFModuleDefinition.h"
#include "llvm/Object/WindowsMachineFlag.h"
#include "llvm/Option/Arg.h"
#include "llvm/Option/ArgList.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/StringSaver.h"
#include "llvm/Support/raw_ostream.h"
#include <optional>
 
using namespace llvm;
using namespace llvm::object;
 
namespace {
 
enum {
  OPT_INVALID = 0,
#define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
#include "Options.inc"
#undef OPTION
};
 
#define PREFIX(NAME, VALUE)                                                    \
  static constexpr StringLiteral NAME##_init[] = VALUE;                        \
  static constexpr ArrayRef<StringLiteral> NAME(NAME##_init,                   \
                                                std::size(NAME##_init) - 1);
#include "Options.inc"
#undef PREFIX
 
static constexpr opt::OptTable::Info InfoTable[] = {
#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12)      \
  {X1, X2, X10,         X11,         OPT_##ID, opt::Option::KIND##Class,       \
   X9, X8, OPT_##GROUP, OPT_##ALIAS, X7,       X12},
#include "Options.inc"
#undef OPTION
};
 
class LibOptTable : public opt::GenericOptTable {
public:
  LibOptTable() : opt::GenericOptTable(InfoTable, true) {}
};
} // namespace
 
static std::string getDefaultOutputPath(const NewArchiveMember &FirstMember) {
  SmallString<128> Val = StringRef(FirstMember.Buf->getBufferIdentifier());
  sys::path::replace_extension(Val, ".lib");
  return std::string(Val.str());
}
 
static std::vector<StringRef> getSearchPaths(opt::InputArgList *Args,
                                             StringSaver &Saver) {
  std::vector<StringRef> Ret;
  // Add current directory as first item of the search path.
  Ret.push_back("");
 
  // Add /libpath flags.
  for (auto *Arg : Args->filtered(OPT_libpath))
    Ret.push_back(Arg->getValue());
 
  // Add $LIB.
  std::optional<std::string> EnvOpt = sys::Process::GetEnv("LIB");
  if (!EnvOpt)
    return Ret;
  StringRef Env = Saver.save(*EnvOpt);
  while (!Env.empty()) {
    StringRef Path;
    std::tie(Path, Env) = Env.split(';');
    Ret.push_back(Path);
  }
  return Ret;
}
 
// Opens a file. Path has to be resolved already. (used for def file)
std::unique_ptr<MemoryBuffer> openFile(const Twine &Path) {
  ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> MB = MemoryBuffer::getFile(Path);
 
  if (std::error_code EC = MB.getError()) {
    llvm::errs() << "cannot open file " << Path << ": " << EC.message() << "\n";
    return nullptr;
  }
 
  return std::move(*MB);
}
 
static std::string findInputFile(StringRef File, ArrayRef<StringRef> Paths) {
  for (StringRef Dir : Paths) {
    SmallString<128> Path = Dir;
    sys::path::append(Path, File);
    if (sys::fs::exists(Path))
      return std::string(Path);
  }
  return "";
}
 
static void fatalOpenError(llvm::Error E, Twine File) {
  if (!E)
    return;
  handleAllErrors(std::move(E), [&](const llvm::ErrorInfoBase &EIB) {
    llvm::errs() << "error opening '" << File << "': " << EIB.message() << '\n';
    exit(1);
  });
}
 
static void doList(opt::InputArgList &Args) {
  // lib.exe prints the contents of the first archive file.
  std::unique_ptr<MemoryBuffer> B;
  for (auto *Arg : Args.filtered(OPT_INPUT)) {
    // Create or open the archive object.
    ErrorOr<std::unique_ptr<MemoryBuffer>> MaybeBuf = MemoryBuffer::getFile(
        Arg->getValue(), /*IsText=*/false, /*RequiresNullTerminator=*/false);
    fatalOpenError(errorCodeToError(MaybeBuf.getError()), Arg->getValue());
 
    if (identify_magic(MaybeBuf.get()->getBuffer()) == file_magic::archive) {
      B = std::move(MaybeBuf.get());
      break;
    }
  }
 
  // lib.exe doesn't print an error if no .lib files are passed.
  if (!B)
    return;
 
  Error Err = Error::success();
  object::Archive Archive(B.get()->getMemBufferRef(), Err);
  fatalOpenError(std::move(Err), B->getBufferIdentifier());
 
  std::vector<StringRef> Names;
  for (auto &C : Archive.children(Err)) {
    Expected<StringRef> NameOrErr = C.getName();
    fatalOpenError(NameOrErr.takeError(), B->getBufferIdentifier());
    Names.push_back(NameOrErr.get());
  }
  for (auto Name : reverse(Names))
    llvm::outs() << Name << '\n';
  fatalOpenError(std::move(Err), B->getBufferIdentifier());
}
 
static Expected<COFF::MachineTypes> getCOFFFileMachine(MemoryBufferRef MB) {
  std::error_code EC;
  auto Obj = object::COFFObjectFile::create(MB);
  if (!Obj)
    return Obj.takeError();
 
  uint16_t Machine = (*Obj)->getMachine();
  if (Machine != COFF::IMAGE_FILE_MACHINE_I386 &&
      Machine != COFF::IMAGE_FILE_MACHINE_AMD64 &&
      Machine != COFF::IMAGE_FILE_MACHINE_ARMNT &&
      Machine != COFF::IMAGE_FILE_MACHINE_ARM64) {
    return createStringError(inconvertibleErrorCode(),
                             "unknown machine: " + std::to_string(Machine));
  }
 
  return static_cast<COFF::MachineTypes>(Machine);
}
 
static Expected<COFF::MachineTypes> getBitcodeFileMachine(MemoryBufferRef MB) {
  Expected<std::string> TripleStr = getBitcodeTargetTriple(MB);
  if (!TripleStr)
    return TripleStr.takeError();
 
  switch (Triple(*TripleStr).getArch()) {
  case Triple::x86:
    return COFF::IMAGE_FILE_MACHINE_I386;
  case Triple::x86_64:
    return COFF::IMAGE_FILE_MACHINE_AMD64;
  case Triple::arm:
    return COFF::IMAGE_FILE_MACHINE_ARMNT;
  case Triple::aarch64:
    return COFF::IMAGE_FILE_MACHINE_ARM64;
  default:
    return createStringError(inconvertibleErrorCode(),
                             "unknown arch in target triple: " + *TripleStr);
  }
}
 
static void appendFile(std::vector<NewArchiveMember> &Members,
                       COFF::MachineTypes &LibMachine,
                       std::string &LibMachineSource, MemoryBufferRef MB) {
  file_magic Magic = identify_magic(MB.getBuffer());
 
  if (Magic != file_magic::coff_object && Magic != file_magic::bitcode &&
      Magic != file_magic::archive && Magic != file_magic::windows_resource &&
      Magic != file_magic::coff_import_library) {
    llvm::errs() << MB.getBufferIdentifier()
                 << ": not a COFF object, bitcode, archive, import library or "
                    "resource file\n";
    exit(1);
  }
 
  // If a user attempts to add an archive to another archive, llvm-lib doesn't
  // handle the first archive file as a single file. Instead, it extracts all
  // members from the archive and add them to the second archive. This behavior
  // is for compatibility with Microsoft's lib command.
  if (Magic == file_magic::archive) {
    Error Err = Error::success();
    object::Archive Archive(MB, Err);
    fatalOpenError(std::move(Err), MB.getBufferIdentifier());
 
    for (auto &C : Archive.children(Err)) {
      Expected<MemoryBufferRef> ChildMB = C.getMemoryBufferRef();
      if (!ChildMB) {
        handleAllErrors(ChildMB.takeError(), [&](const ErrorInfoBase &EIB) {
          llvm::errs() << MB.getBufferIdentifier() << ": " << EIB.message()
                       << "\n";
        });
        exit(1);
      }
 
      appendFile(Members, LibMachine, LibMachineSource, *ChildMB);
    }
 
    fatalOpenError(std::move(Err), MB.getBufferIdentifier());
    return;
  }
 
  // Check that all input files have the same machine type.
  // Mixing normal objects and LTO bitcode files is fine as long as they
  // have the same machine type.
  // Doing this here duplicates the header parsing work that writeArchive()
  // below does, but it's not a lot of work and it's a bit awkward to do
  // in writeArchive() which needs to support many tools, can't assume the
  // input is COFF, and doesn't have a good way to report errors.
  if (Magic == file_magic::coff_object || Magic == file_magic::bitcode) {
    Expected<COFF::MachineTypes> MaybeFileMachine =
        (Magic == file_magic::coff_object) ? getCOFFFileMachine(MB)
                                           : getBitcodeFileMachine(MB);
    if (!MaybeFileMachine) {
      handleAllErrors(MaybeFileMachine.takeError(),
                      [&](const ErrorInfoBase &EIB) {
                        llvm::errs() << MB.getBufferIdentifier() << ": "
                                     << EIB.message() << "\n";
                      });
      exit(1);
    }
    COFF::MachineTypes FileMachine = *MaybeFileMachine;
 
    // FIXME: Once lld-link rejects multiple resource .obj files:
    // Call convertResToCOFF() on .res files and add the resulting
    // COFF file to the .lib output instead of adding the .res file, and remove
    // this check. See PR42180.
    if (FileMachine != COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
      if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
        LibMachine = FileMachine;
        LibMachineSource =
            (" (inferred from earlier file '" + MB.getBufferIdentifier() + "')")
                .str();
      } else if (LibMachine != FileMachine) {
        llvm::errs() << MB.getBufferIdentifier() << ": file machine type "
                     << machineToStr(FileMachine)
                     << " conflicts with library machine type "
                     << machineToStr(LibMachine) << LibMachineSource << '\n';
        exit(1);
      }
    }
  }
 
  Members.emplace_back(MB);
}
 
int llvm::libDriverMain(ArrayRef<const char *> ArgsArr) {
  BumpPtrAllocator Alloc;
  StringSaver Saver(Alloc);
 
  // Parse command line arguments.
  SmallVector<const char *, 20> NewArgs(ArgsArr.begin(), ArgsArr.end());
  cl::ExpandResponseFiles(Saver, cl::TokenizeWindowsCommandLine, NewArgs);
  ArgsArr = NewArgs;
 
  LibOptTable Table;
  unsigned MissingIndex;
  unsigned MissingCount;
  opt::InputArgList Args =
      Table.ParseArgs(ArgsArr.slice(1), MissingIndex, MissingCount);
  if (MissingCount) {
    llvm::errs() << "missing arg value for \""
                 << Args.getArgString(MissingIndex) << "\", expected "
                 << MissingCount
                 << (MissingCount == 1 ? " argument.\n" : " arguments.\n");
    return 1;
  }
  for (auto *Arg : Args.filtered(OPT_UNKNOWN))
    llvm::errs() << "ignoring unknown argument: " << Arg->getAsString(Args)
                 << "\n";
 
  // Handle /help
  if (Args.hasArg(OPT_help)) {
    Table.printHelp(outs(), "llvm-lib [options] file...", "LLVM Lib");
    return 0;
  }
 
  // Parse /ignore:
  llvm::StringSet<> IgnoredWarnings;
  for (auto *Arg : Args.filtered(OPT_ignore))
    IgnoredWarnings.insert(Arg->getValue());
 
  // get output library path, if any
  std::string OutputPath;
  if (auto *Arg = Args.getLastArg(OPT_out)) {
    OutputPath = Arg->getValue();
  }
 
  COFF::MachineTypes LibMachine = COFF::IMAGE_FILE_MACHINE_UNKNOWN;
  std::string LibMachineSource;
  if (auto *Arg = Args.getLastArg(OPT_machine)) {
    LibMachine = getMachineType(Arg->getValue());
    if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
      llvm::errs() << "unknown /machine: arg " << Arg->getValue() << '\n';
      return 1;
    }
    LibMachineSource =
        std::string(" (from '/machine:") + Arg->getValue() + "' flag)";
  }
 
  // create an import library
  if (Args.hasArg(OPT_deffile)) {
 
    if (OutputPath.empty()) {
      llvm::errs() << "no output path given\n";
      return 1;
    }
 
    if (LibMachine == COFF::IMAGE_FILE_MACHINE_UNKNOWN) {
      llvm::errs() << "/def option requires /machine to be specified" << '\n';
      return 1;
    }
 
    std::unique_ptr<MemoryBuffer> MB =
        openFile(Args.getLastArg(OPT_deffile)->getValue());
    if (!MB)
      return 1;
 
    if (!MB->getBufferSize()) {
      llvm::errs() << "definition file empty\n";
      return 1;
    }
 
    Expected<COFFModuleDefinition> Def =
        parseCOFFModuleDefinition(*MB, LibMachine, true);
 
    if (!Def) {
      llvm::errs() << "error parsing definition\n"
                   << errorToErrorCode(Def.takeError()).message();
      return 1;
    }
 
    return writeImportLibrary(Def->OutputFile, OutputPath, Def->Exports,
                              LibMachine,
                              /*MinGW=*/false)
               ? 1
               : 0;
  }
 
  // If no input files and not told otherwise, silently do nothing to match
  // lib.exe
  if (!Args.hasArgNoClaim(OPT_INPUT) && !Args.hasArg(OPT_llvmlibempty)) {
    if (!IgnoredWarnings.contains("emptyoutput")) {
      llvm::errs() << "warning: no input files, not writing output file\n";
      llvm::errs() << "         pass /llvmlibempty to write empty .lib file,\n";
      llvm::errs() << "         pass /ignore:emptyoutput to suppress warning\n";
      if (Args.hasFlag(OPT_WX, OPT_WX_no, false)) {
        llvm::errs() << "treating warning as error due to /WX\n";
        return 1;
      }
    }
    return 0;
  }
 
  if (Args.hasArg(OPT_lst)) {
    doList(Args);
    return 0;
  }
 
  std::vector<StringRef> SearchPaths = getSearchPaths(&Args, Saver);
 
  std::vector<std::unique_ptr<MemoryBuffer>> MBs;
  StringSet<> Seen;
  std::vector<NewArchiveMember> Members;
 
  // Create a NewArchiveMember for each input file.
  for (auto *Arg : Args.filtered(OPT_INPUT)) {
    // Find a file
    std::string Path = findInputFile(Arg->getValue(), SearchPaths);
    if (Path.empty()) {
      llvm::errs() << Arg->getValue() << ": no such file or directory\n";
      return 1;
    }
 
    // Input files are uniquified by pathname. If you specify the exact same
    // path more than once, all but the first one are ignored.
    //
    // Note that there's a loophole in the rule; you can prepend `.\` or
    // something like that to a path to make it look different, and they are
    // handled as if they were different files. This behavior is compatible with
    // Microsoft lib.exe.
    if (!Seen.insert(Path).second)
      continue;
 
    // Open a file.
    ErrorOr<std::unique_ptr<MemoryBuffer>> MOrErr = MemoryBuffer::getFile(
        Path, /*IsText=*/false, /*RequiresNullTerminator=*/false);
    fatalOpenError(errorCodeToError(MOrErr.getError()), Path);
    MemoryBufferRef MBRef = (*MOrErr)->getMemBufferRef();
 
    // Append a file.
    appendFile(Members, LibMachine, LibMachineSource, MBRef);
 
    // Take the ownership of the file buffer to keep the file open.
    MBs.push_back(std::move(*MOrErr));
  }
 
  // Create an archive file.
  if (OutputPath.empty()) {
    if (!Members.empty()) {
      OutputPath = getDefaultOutputPath(Members[0]);
    } else {
      llvm::errs() << "no output path given, and cannot infer with no inputs\n";
      return 1;
    }
  }
  // llvm-lib uses relative paths for both regular and thin archives, unlike
  // standard GNU ar, which only uses relative paths for thin archives and
  // basenames for regular archives.
  for (NewArchiveMember &Member : Members) {
    if (sys::path::is_relative(Member.MemberName)) {
      Expected<std::string> PathOrErr =
          computeArchiveRelativePath(OutputPath, Member.MemberName);
      if (PathOrErr)
        Member.MemberName = Saver.save(*PathOrErr);
    }
  }
 
  // For compatibility with MSVC, reverse member vector after de-duplication.
  std::reverse(Members.begin(), Members.end());
 
  if (Error E =
          writeArchive(OutputPath, Members,
                       /*WriteSymtab=*/true, object::Archive::K_GNU,
                       /*Deterministic*/ true, Args.hasArg(OPT_llvmlibthin))) {
    handleAllErrors(std::move(E), [&](const ErrorInfoBase &EI) {
      llvm::errs() << OutputPath << ": " << EI.message() << "\n";
    });
    return 1;
  }
 
  return 0;
}