LibDriver.cpp

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//===- 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/BinaryFormat/Magic.h"
#include "llvm/Object/ArchiveWriter.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"

using namespace llvm;

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) const char *const NAME[] = VALUE;
#include "Options.inc"
#undef PREFIX

static const 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::OptTable {
public:
  LibOptTable() : OptTable(InfoTable, true) {}
};

}

static std::string getOutputPath(opt::InputArgList *Args,
                                 const NewArchiveMember &FirstMember) {
  if (auto *Arg = Args->getLastArg(OPT_out))
    return Arg->getValue();
  SmallString<128> Val = StringRef(FirstMember.Buf->getBufferIdentifier());
  sys::path::replace_extension(Val, ".lib");
  return 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.
  Optional<std::string> EnvOpt = sys::Process::GetEnv("LIB");
  if (!EnvOpt.hasValue())
    return Ret;
  StringRef Env = Saver.save(*EnvOpt);
  while (!Env.empty()) {
    StringRef Path;
    std::tie(Path, Env) = Env.split(';');
    Ret.push_back(Path);
  }
  return Ret;
}

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 Path.str().str();
  }
  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(), -1, 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());

  for (auto &C : Archive.children(Err)) {
    Expected<StringRef> NameOrErr = C.getName();
    fatalOpenError(NameOrErr.takeError(), B->getBufferIdentifier());
    StringRef Name = NameOrErr.get();
    llvm::outs() << Name << '\n';
  }
  fatalOpenError(std::move(Err), B->getBufferIdentifier());
}

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->getSpelling() << "\n";

  // Handle /help
  if (Args.hasArg(OPT_help)) {
    Table.PrintHelp(outs(), "llvm-lib [options] file...", "LLVM Lib");
    return 0;
  }

  // If no input files, silently do nothing to match lib.exe.
  if (!Args.hasArgNoClaim(OPT_INPUT))
    return 0;

  if (Args.hasArg(OPT_lst)) {
    doList(Args);
    return 0;
  }

  std::vector<StringRef> SearchPaths = getSearchPaths(&Args, Saver);

  // Create a NewArchiveMember for each input file.
  std::vector<NewArchiveMember> Members;
  for (auto *Arg : Args.filtered(OPT_INPUT)) {
    std::string Path = findInputFile(Arg->getValue(), SearchPaths);
    if (Path.empty()) {
      llvm::errs() << Arg->getValue() << ": no such file or directory\n";
      return 1;
    }

    Expected<NewArchiveMember> MOrErr =
        NewArchiveMember::getFile(Saver.save(Path), /*Deterministic=*/true);
    if (!MOrErr) {
      handleAllErrors(MOrErr.takeError(), [&](const ErrorInfoBase &EIB) {
        llvm::errs() << Arg->getValue() << ": " << EIB.message() << "\n";
      });
      return 1;
    }

    file_magic Magic = identify_magic(MOrErr->Buf->getBuffer());
    if (Magic != file_magic::coff_object && Magic != file_magic::bitcode &&
        Magic != file_magic::windows_resource) {
      llvm::errs() << Arg->getValue()
                   << ": not a COFF object, bitcode or resource file\n";
      return 1;
    }
    Members.emplace_back(std::move(*MOrErr));
  }

  // Create an archive file.
  std::string OutputPath = getOutputPath(&Args, Members[0]);
  // 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)
    Member.MemberName =
        Saver.save(computeArchiveRelativePath(OutputPath, Member.MemberName));

  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;
}