hanchenye-llvm-project/lld/lib/Driver/Driver.cpp

//===- lib/Driver/Driver.cpp - Linker Driver Emulator ---------------------===//
//
//                             The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lld/Driver/Driver.h"
#include "lld/Core/LLVM.h"
#include "lld/Core/InputFiles.h"
#include "lld/Core/Resolver.h"
#include "lld/Core/PassManager.h"
#include "lld/ReaderWriter/Reader.h"
#include "lld/ReaderWriter/Writer.h"

#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Option/Arg.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"

namespace lld {

/// This is where the link is actually performed.
bool Driver::link(const TargetInfo &targetInfo, raw_ostream &diagnostics) {
  // Honor -mllvm
  if (!targetInfo.llvmOptions().empty()) {
    unsigned numArgs = targetInfo.llvmOptions().size();
    const char **args = new const char*[numArgs + 2];
    args[0] = "lld (LLVM option parsing)";
    for (unsigned i = 0; i != numArgs; ++i)
      args[i + 1] = targetInfo.llvmOptions()[i];
    args[numArgs + 1] = 0;
    llvm::cl::ParseCommandLineOptions(numArgs + 1, args);
  }

  // Read inputs
  InputFiles inputs;
  for (const auto &input : targetInfo.inputFiles()) {
    std::vector<std::unique_ptr<File>> files;
    if (targetInfo.logInputFiles())
      llvm::outs() << input.getPath() << "\n";
      
    error_code ec = targetInfo.readFile(input.getPath(), files);
    if (ec) {
      diagnostics   << "Failed to read file: " << input.getPath() << ": "
                    << ec.message() << "\n";
      return true;
    }
    inputs.appendFiles(files);
  }

  // Give target a chance to add files.
  targetInfo.addImplicitFiles(inputs);

  // assign an ordinal to each file so sort() can preserve command line order
  inputs.assignFileOrdinals();

  // Do core linking.
  Resolver resolver(targetInfo, inputs);
  if (resolver.resolve()) {
    if (!targetInfo.allowRemainingUndefines())
      return true;
  }
  MutableFile &merged = resolver.resultFile();

  // Run passes on linked atoms.
  PassManager pm;
  targetInfo.addPasses(pm);
  pm.runOnFile(merged);

  // Give linked atoms to Writer to generate output file.
  if (error_code ec = targetInfo.writeFile(merged)) {
    diagnostics << "Failed to write file '" << targetInfo.outputPath() 
                << "': " << ec.message() << "\n";
    return true;
  }

  return false;
}


} // namespace