//===--- Hurd.cpp - Hurd ToolChain Implementations --------*- C++ -*-===//

//

// 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

//

//===----------------------------------------------------------------------===//

#include "Hurd.h"

#include "CommonArgs.h"

#include "clang/Config/config.h"

#include "clang/Driver/Driver.h"

#include "clang/Driver/Options.h"

#include "llvm/Support/Path.h"

#include "llvm/Support/VirtualFileSystem.h"

using namespace clang::driver;

using namespace clang::driver::toolchains;

using namespace clang;

using namespace llvm::opt;

using tools::addPathIfExists;

/// Get our best guess at the multiarch triple for a target.

///

/// Debian-based systems are starting to use a multiarch setup where they use

/// a target-triple directory in the library and header search paths.

/// Unfortunately, this triple does not align with the vanilla target triple,

/// so we provide a rough mapping here.

std::string Hurd::getMultiarchTriple(const Driver &D,

                                     const llvm::Triple &TargetTriple,

                                     StringRef SysRoot) const {

  if (TargetTriple.getArch() == llvm::Triple::x86) {

    // We use the existence of '/lib/<triple>' as a directory to detect some

    // common hurd triples that don't quite match the Clang triple for both

    // 32-bit and 64-bit targets. Multiarch fixes its install triples to these

    // regardless of what the actual target triple is.

    if (D.getVFS().exists(SysRoot + "/lib/i386-gnu"))

      return "i386-gnu";

  }

  // For most architectures, just use whatever we have rather than trying to be

  // clever.

  return TargetTriple.str();

}

static StringRef getOSLibDir(const llvm::Triple &Triple, const ArgList &Args) {

  // It happens that only x86 and PPC use the 'lib32' variant of oslibdir, and

  // using that variant while targeting other architectures causes problems

  // because the libraries are laid out in shared system roots that can't cope

  // with a 'lib32' library search path being considered. So we only enable

  // them when we know we may need it.

  //

  // FIXME: This is a bit of a hack. We should really unify this code for

  // reasoning about oslibdir spellings with the lib dir spellings in the

  // GCCInstallationDetector, but that is a more significant refactoring.

  if (Triple.getArch() == llvm::Triple::x86)

    return "lib32";

  return Triple.isArch32Bit() ? 
"lib"0
 : "lib64";

}

Hurd::Hurd(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)

    : Generic_ELF(D, Triple, Args) {

  GCCInstallation.init(Triple, Args);

  Multilibs = GCCInstallation.getMultilibs();

  SelectedMultilibs.assign({GCCInstallation.getMultilib()});

  std::string SysRoot = computeSysRoot();

  ToolChain::path_list &PPaths = getProgramPaths();

  Generic_GCC::PushPPaths(PPaths);

  // The selection of paths to try here is designed to match the patterns which

  // the GCC driver itself uses, as this is part of the GCC-compatible driver.

  // This was determined by running GCC in a fake filesystem, creating all

  // possible permutations of these directories, and seeing which ones it added

  // to the link paths.

  path_list &Paths = getFilePaths();

  const std::string OSLibDir = std::string(getOSLibDir(Triple, Args));

  const std::string MultiarchTriple = getMultiarchTriple(D, Triple, SysRoot);

#ifdef ENABLE_LINKER_BUILD_ID

  ExtraOpts.push_back("--build-id");

#endif

  Generic_GCC::AddMultilibPaths(D, SysRoot, OSLibDir, MultiarchTriple, Paths);

  // Similar to the logic for GCC above, if we currently running Clang inside

  // of the requested system root, add its parent library paths to

  // those searched.

  // FIXME: It's not clear whether we should use the driver's installed

  // directory ('Dir' below) or the ResourceDir.

  if (StringRef(D.Dir).startswith(SysRoot)) {

    addPathIfExists(D, D.Dir + "/../lib/" + MultiarchTriple, Paths);

    addPathIfExists(D, D.Dir + "/../" + OSLibDir, Paths);

  }

  addPathIfExists(D, SysRoot + "/lib/" + MultiarchTriple, Paths);

  addPathIfExists(D, SysRoot + "/lib/../" + OSLibDir, Paths);

  addPathIfExists(D, SysRoot + "/usr/lib/" + MultiarchTriple, Paths);

  addPathIfExists(D, SysRoot + "/usr/lib/../" + OSLibDir, Paths);

  Generic_GCC::AddMultiarchPaths(D, SysRoot, OSLibDir, Paths);

  // Similar to the logic for GCC above, if we are currently running Clang

  // inside of the requested system root, add its parent library path to those

  // searched.

  // FIXME: It's not clear whether we should use the driver's installed

  // directory ('Dir' below) or the ResourceDir.

  if (StringRef(D.Dir).startswith(SysRoot))

    addPathIfExists(D, D.Dir + "/../lib", Paths);

  addPathIfExists(D, SysRoot + "/lib", Paths);

  addPathIfExists(D, SysRoot + "/usr/lib", Paths);

}

bool Hurd::HasNativeLLVMSupport() const { return true; }

Tool *Hurd::buildLinker() const { return new tools::gnutools::Linker(*this); }

Tool *Hurd::buildAssembler() const {

  return new tools::gnutools::Assembler(*this);

}

std::string Hurd::getDynamicLinker(const ArgList &Args) const {

  if (getArch() == llvm::Triple::x86)

    return "/lib/ld.so";

  llvm_unreachable("unsupported architecture");

}

void Hurd::AddClangSystemIncludeArgs(const ArgList &DriverArgs,

                                     ArgStringList &CC1Args) const {

  const Driver &D = getDriver();

  std::string SysRoot = computeSysRoot();

  if (DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))

    return;

  if (!DriverArgs.hasArg(options::OPT_nostdlibinc))

    addSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/local/include");

  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {

    SmallString<128> P(D.ResourceDir);

    llvm::sys::path::append(P, "include");

    addSystemInclude(DriverArgs, CC1Args, P);

  }

  if (DriverArgs.hasArg(options::OPT_nostdlibinc))

    return;

  // Check for configure-time C include directories.

  StringRef CIncludeDirs(C_INCLUDE_DIRS);

  if (CIncludeDirs != "") {

    SmallVector<StringRef, 5> Dirs;

    CIncludeDirs.split(Dirs, ":");

    for (StringRef Dir : Dirs) {

      StringRef Prefix =

          llvm::sys::path::is_absolute(Dir) ? "" : StringRef(SysRoot);

      addExternCSystemInclude(DriverArgs, CC1Args, Prefix + Dir);

    }

    return;

  }

  // Lacking those, try to detect the correct set of system includes for the

  // target triple.

  AddMultilibIncludeArgs(DriverArgs, CC1Args);

  // On systems using multiarch, add /usr/include/$triple before

  // /usr/include.

  std::string MultiarchIncludeDir = getMultiarchTriple(D, getTriple(), SysRoot);

  if (!MultiarchIncludeDir.empty() &&

      D.getVFS().exists(SysRoot + "/usr/include/" + MultiarchIncludeDir))

    addExternCSystemInclude(DriverArgs, CC1Args,

                            SysRoot + "/usr/include/" + MultiarchIncludeDir);

  // Add an include of '/include' directly. This isn't provided by default by

  // system GCCs, but is often used with cross-compiling GCCs, and harmless to

  // add even when Clang is acting as-if it were a system compiler.

  addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/include");

  addExternCSystemInclude(DriverArgs, CC1Args, SysRoot + "/usr/include");

}

void Hurd::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,

                                    llvm::opt::ArgStringList &CC1Args) const {

  // We need a detected GCC installation on Linux to provide libstdc++'s

  // headers in odd Linuxish places.

  if (!GCCInstallation.isValid())

    return;

  StringRef TripleStr = GCCInstallation.getTriple().str();

  StringRef DebianMultiarch =

      GCCInstallation.getTriple().getArch() == llvm::Triple::x86 ? "i386-gnu"

                                                                 : 
TripleStr0
;

  addGCCLibStdCxxIncludePaths(DriverArgs, CC1Args, DebianMultiarch);

}

void Hurd::addExtraOpts(llvm::opt::ArgStringList &CmdArgs) const {

  for (const auto &Opt : ExtraOpts)

    CmdArgs.push_back(Opt.c_str());

}