hanchenye-llvm-project/lld/ELF/DriverUtils.cpp

//===- DriverUtils.cpp ----------------------------------------------------===//
//
//                             The LLVM Linker
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains utility functions for the driver. Because there
// are so many small functions, we created this separate file to make
// Driver.cpp less cluttered.
//
//===----------------------------------------------------------------------===//

#include "Driver.h"
#include "Error.h"
#include "lld/Config/Version.h"
#include "lld/Core/Reproduce.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Option/Option.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/StringSaver.h"

using namespace llvm;
using namespace llvm::sys;

using namespace lld;
using namespace lld::elf;

// Create OptTable

// Create prefix string literals used in Options.td
#define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
#include "Options.inc"
#undef PREFIX

// Create table mapping all options defined in Options.td
static const opt::OptTable::Info OptInfo[] = {
#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X6, X7, X8, X9, X10)            \
  {                                                                            \
    X1, X2, X9, X10, OPT_##ID, opt::Option::KIND##Class, X8, X7, OPT_##GROUP,  \
        OPT_##ALIAS, X6                                                        \
  },
#include "Options.inc"
#undef OPTION
};

ELFOptTable::ELFOptTable() : OptTable(OptInfo) {}

static cl::TokenizerCallback getQuotingStyle(opt::InputArgList &Args) {
  if (auto *Arg = Args.getLastArg(OPT_rsp_quoting)) {
    StringRef S = Arg->getValue();
    if (S != "windows" && S != "posix")
      error("invalid response file quoting: " + S);
    if (S == "windows")
      return cl::TokenizeWindowsCommandLine;
    return cl::TokenizeGNUCommandLine;
  }
  if (Triple(sys::getProcessTriple()).getOS() == Triple::Win32)
    return cl::TokenizeWindowsCommandLine;
  return cl::TokenizeGNUCommandLine;
}

// Parses a given list of options.
opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
  // Make InputArgList from string vectors.
  unsigned MissingIndex;
  unsigned MissingCount;
  SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());

  // We need to get the quoting style for response files before parsing all
  // options so we parse here before and ignore all the options but
  // --rsp-quoting.
  opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);

  // Expand response files. '@<filename>' is replaced by the file's contents.
  StringSaver Saver(Alloc);
  cl::ExpandResponseFiles(Saver, getQuotingStyle(Args), Vec);

  // Parse options and then do error checking.
  Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
  if (MissingCount)
    error(Twine("missing arg value for \"") + Args.getArgString(MissingIndex) +
          "\", expected " + Twine(MissingCount) +
          (MissingCount == 1 ? " argument.\n" : " arguments"));

  for (auto *Arg : Args.filtered(OPT_UNKNOWN))
    error("unknown argument: " + Arg->getSpelling());
  return Args;
}

void elf::printHelp(const char *Argv0) {
  ELFOptTable Table;
  Table.PrintHelp(outs(), Argv0, "lld", false);
}

std::string elf::getVersionString() {
  std::string Version = getLLDVersion();
  std::string Repo = getLLDRepositoryVersion();
  if (Repo.empty())
    return "LLD " + Version + "\n";
  return "LLD " + Version + " " + Repo + "\n";
}

// Reconstructs command line arguments so that so that you can re-run
// the same command with the same inputs. This is for --reproduce.
std::string elf::createResponseFile(const opt::InputArgList &Args) {
  SmallString<0> Data;
  raw_svector_ostream OS(Data);

  // Copy the command line to the output while rewriting paths.
  for (auto *Arg : Args) {
    switch (Arg->getOption().getID()) {
    case OPT_reproduce:
      break;
    case OPT_INPUT:
      OS << quote(rewritePath(Arg->getValue())) << "\n";
      break;
    case OPT_L:
    case OPT_dynamic_list:
    case OPT_rpath:
    case OPT_alias_script_T:
    case OPT_script:
    case OPT_version_script:
      OS << Arg->getSpelling() << " " << quote(rewritePath(Arg->getValue()))
         << "\n";
      break;
    default:
      OS << stringize(Arg) << "\n";
    }
  }
  return Data.str();
}

std::string elf::findFromSearchPaths(StringRef Path) {
  for (StringRef Dir : Config->SearchPaths) {
    std::string FullPath = buildSysrootedPath(Dir, Path);
    if (fs::exists(FullPath))
      return FullPath;
  }
  return "";
}

// Searches a given library from input search paths, which are filled
// from -L command line switches. Returns a path to an existent library file.
std::string elf::searchLibrary(StringRef Path) {
  if (Path.startswith(":"))
    return findFromSearchPaths(Path.substr(1));
  for (StringRef Dir : Config->SearchPaths) {
    if (!Config->Static) {
      std::string S = buildSysrootedPath(Dir, ("lib" + Path + ".so").str());
      if (fs::exists(S))
        return S;
    }
    std::string S = buildSysrootedPath(Dir, ("lib" + Path + ".a").str());
    if (fs::exists(S))
      return S;
  }
  return "";
}

// Makes a path by concatenating Dir and File.
// If Dir starts with '=' the result will be preceded by Sysroot,
// which can be set with --sysroot command line switch.
std::string elf::buildSysrootedPath(StringRef Dir, StringRef File) {
  SmallString<128> Path;
  if (Dir.startswith("="))
    path::append(Path, Config->Sysroot, Dir.substr(1), File);
  else
    path::append(Path, Dir, File);
  return Path.str();
}