Import LLVM 10.0.0 release including clang, lld and lldb.

ok hackroom
tested by plenty

1 files changed, 2869 insertions, 0 deletions

diff --git a/gnu/llvm/clang/lib/Driver/ToolChains/Gnu.cpp b/gnu/llvm/clang/lib/Driver/ToolChains/Gnu.cpp
new file mode 100644
index 00000000000..a55d59cb11b
--- /dev/null
+++ b/gnu/llvm/clang/lib/Driver/ToolChains/Gnu.cpp
@@ -0,0 +1,2869 @@
+//===--- Gnu.cpp - Gnu Tool and 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 "Gnu.h"
+#include "Arch/ARM.h"
+#include "Arch/Mips.h"
+#include "Arch/PPC.h"
+#include "Arch/RISCV.h"
+#include "Arch/Sparc.h"
+#include "Arch/SystemZ.h"
+#include "CommonArgs.h"
+#include "Linux.h"
+#include "clang/Config/config.h" // for GCC_INSTALL_PREFIX
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "clang/Driver/Tool.h"
+#include "clang/Driver/ToolChain.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/TargetParser.h"
+#include "llvm/Support/VirtualFileSystem.h"
+#include <system_error>
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang;
+using namespace llvm::opt;
+
+using tools::addMultilibFlag;
+
+void tools::GnuTool::anchor() {}
+
+static bool forwardToGCC(const Option &O) {
+  // Don't forward inputs from the original command line.  They are added from
+  // InputInfoList.
+  return O.getKind() != Option::InputClass &&
+         !O.hasFlag(options::DriverOption) && !O.hasFlag(options::LinkerInput);
+}
+
+// Switch CPU names not recognized by GNU assembler to a close CPU that it does
+// recognize, instead of a lower march from being picked in the absence of a cpu
+// flag.
+static void normalizeCPUNamesForAssembler(const ArgList &Args,
+                                          ArgStringList &CmdArgs) {
+  if (Arg *A = Args.getLastArg(options::OPT_mcpu_EQ)) {
+    StringRef CPUArg(A->getValue());
+    if (CPUArg.equals_lower("krait"))
+      CmdArgs.push_back("-mcpu=cortex-a15");
+    else if(CPUArg.equals_lower("kryo"))
+      CmdArgs.push_back("-mcpu=cortex-a57");
+    else
+      Args.AddLastArg(CmdArgs, options::OPT_mcpu_EQ);
+  }
+}
+
+void tools::gcc::Common::ConstructJob(Compilation &C, const JobAction &JA,
+                                      const InputInfo &Output,
+                                      const InputInfoList &Inputs,
+                                      const ArgList &Args,
+                                      const char *LinkingOutput) const {
+  const Driver &D = getToolChain().getDriver();
+  ArgStringList CmdArgs;
+
+  for (const auto &A : Args) {
+    if (forwardToGCC(A->getOption())) {
+      // It is unfortunate that we have to claim here, as this means
+      // we will basically never report anything interesting for
+      // platforms using a generic gcc, even if we are just using gcc
+      // to get to the assembler.
+      A->claim();
+
+      // Don't forward any -g arguments to assembly steps.
+      if (isa<AssembleJobAction>(JA) &&
+          A->getOption().matches(options::OPT_g_Group))
+        continue;
+
+      // Don't forward any -W arguments to assembly and link steps.
+      if ((isa<AssembleJobAction>(JA) || isa<LinkJobAction>(JA)) &&
+          A->getOption().matches(options::OPT_W_Group))
+        continue;
+
+      // Don't forward -mno-unaligned-access since GCC doesn't understand
+      // it and because it doesn't affect the assembly or link steps.
+      if ((isa<AssembleJobAction>(JA) || isa<LinkJobAction>(JA)) &&
+          (A->getOption().matches(options::OPT_munaligned_access) ||
+           A->getOption().matches(options::OPT_mno_unaligned_access)))
+        continue;
+
+      A->render(Args, CmdArgs);
+    }
+  }
+
+  RenderExtraToolArgs(JA, CmdArgs);
+
+  // If using a driver driver, force the arch.
+  if (getToolChain().getTriple().isOSDarwin()) {
+    CmdArgs.push_back("-arch");
+    CmdArgs.push_back(
+        Args.MakeArgString(getToolChain().getDefaultUniversalArchName()));
+  }
+
+  // Try to force gcc to match the tool chain we want, if we recognize
+  // the arch.
+  //
+  // FIXME: The triple class should directly provide the information we want
+  // here.
+  switch (getToolChain().getArch()) {
+  default:
+    break;
+  case llvm::Triple::x86:
+  case llvm::Triple::ppc:
+    CmdArgs.push_back("-m32");
+    break;
+  case llvm::Triple::x86_64:
+  case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
+    CmdArgs.push_back("-m64");
+    break;
+  case llvm::Triple::sparcel:
+    CmdArgs.push_back("-EL");
+    break;
+  }
+
+  if (Output.isFilename()) {
+    CmdArgs.push_back("-o");
+    CmdArgs.push_back(Output.getFilename());
+  } else {
+    assert(Output.isNothing() && "Unexpected output");
+    CmdArgs.push_back("-fsyntax-only");
+  }
+
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);
+
+  // Only pass -x if gcc will understand it; otherwise hope gcc
+  // understands the suffix correctly. The main use case this would go
+  // wrong in is for linker inputs if they happened to have an odd
+  // suffix; really the only way to get this to happen is a command
+  // like '-x foobar a.c' which will treat a.c like a linker input.
+  //
+  // FIXME: For the linker case specifically, can we safely convert
+  // inputs into '-Wl,' options?
+  for (const auto &II : Inputs) {
+    // Don't try to pass LLVM or AST inputs to a generic gcc.
+    if (types::isLLVMIR(II.getType()))
+      D.Diag(clang::diag::err_drv_no_linker_llvm_support)
+          << getToolChain().getTripleString();
+    else if (II.getType() == types::TY_AST)
+      D.Diag(diag::err_drv_no_ast_support) << getToolChain().getTripleString();
+    else if (II.getType() == types::TY_ModuleFile)
+      D.Diag(diag::err_drv_no_module_support)
+          << getToolChain().getTripleString();
+
+    if (types::canTypeBeUserSpecified(II.getType())) {
+      CmdArgs.push_back("-x");
+      CmdArgs.push_back(types::getTypeName(II.getType()));
+    }
+
+    if (II.isFilename())
+      CmdArgs.push_back(II.getFilename());
+    else {
+      const Arg &A = II.getInputArg();
+
+      // Reverse translate some rewritten options.
+      if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx)) {
+        CmdArgs.push_back("-lstdc++");
+        continue;
+      }
+
+      // Don't render as input, we need gcc to do the translations.
+      A.render(Args, CmdArgs);
+    }
+  }
+
+  const std::string &customGCCName = D.getCCCGenericGCCName();
+  const char *GCCName;
+  if (!customGCCName.empty())
+    GCCName = customGCCName.c_str();
+  else if (D.CCCIsCXX()) {
+    GCCName = "g++";
+  } else
+    GCCName = "gcc";
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath(GCCName));
+  C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+}
+
+void tools::gcc::Preprocessor::RenderExtraToolArgs(
+    const JobAction &JA, ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-E");
+}
+
+void tools::gcc::Compiler::RenderExtraToolArgs(const JobAction &JA,
+                                               ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  switch (JA.getType()) {
+  // If -flto, etc. are present then make sure not to force assembly output.
+  case types::TY_LLVM_IR:
+  case types::TY_LTO_IR:
+  case types::TY_LLVM_BC:
+  case types::TY_LTO_BC:
+    CmdArgs.push_back("-c");
+    break;
+  // We assume we've got an "integrated" assembler in that gcc will produce an
+  // object file itself.
+  case types::TY_Object:
+    CmdArgs.push_back("-c");
+    break;
+  case types::TY_PP_Asm:
+    CmdArgs.push_back("-S");
+    break;
+  case types::TY_Nothing:
+    CmdArgs.push_back("-fsyntax-only");
+    break;
+  default:
+    D.Diag(diag::err_drv_invalid_gcc_output_type) << getTypeName(JA.getType());
+  }
+}
+
+void tools::gcc::Linker::RenderExtraToolArgs(const JobAction &JA,
+                                             ArgStringList &CmdArgs) const {
+  // The types are (hopefully) good enough.
+}
+
+// On Arm the endianness of the output file is determined by the target and
+// can be overridden by the pseudo-target flags '-mlittle-endian'/'-EL' and
+// '-mbig-endian'/'-EB'. Unlike other targets the flag does not result in a
+// normalized triple so we must handle the flag here.
+static bool isArmBigEndian(const llvm::Triple &Triple,
+                           const ArgList &Args) {
+  bool IsBigEndian = false;
+  switch (Triple.getArch()) {
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumbeb:
+    IsBigEndian = true;
+    LLVM_FALLTHROUGH;
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    if (Arg *A = Args.getLastArg(options::OPT_mlittle_endian,
+                               options::OPT_mbig_endian))
+      IsBigEndian = !A->getOption().matches(options::OPT_mlittle_endian);
+    break;
+  default:
+    break;
+  }
+  return IsBigEndian;
+}
+
+static const char *getLDMOption(const llvm::Triple &T, const ArgList &Args) {
+  switch (T.getArch()) {
+  case llvm::Triple::x86:
+    if (T.isOSIAMCU())
+      return "elf_iamcu";
+    return "elf_i386";
+  case llvm::Triple::aarch64:
+    return "aarch64linux";
+  case llvm::Triple::aarch64_be:
+    return "aarch64linuxb";
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumbeb:
+    return isArmBigEndian(T, Args) ? "armelfb_linux_eabi" : "armelf_linux_eabi";
+  case llvm::Triple::ppc:
+    return "elf32ppclinux";
+  case llvm::Triple::ppc64:
+    return "elf64ppc";
+  case llvm::Triple::ppc64le:
+    return "elf64lppc";
+  case llvm::Triple::riscv32:
+    return "elf32lriscv";
+  case llvm::Triple::riscv64:
+    return "elf64lriscv";
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel:
+    return "elf32_sparc";
+  case llvm::Triple::sparcv9:
+    return "elf64_sparc";
+  case llvm::Triple::mips:
+    return "elf32btsmip";
+  case llvm::Triple::mipsel:
+    return "elf32ltsmip";
+  case llvm::Triple::mips64:
+    if (tools::mips::hasMipsAbiArg(Args, "n32") ||
+        T.getEnvironment() == llvm::Triple::GNUABIN32)
+      return "elf32btsmipn32";
+    return "elf64btsmip";
+  case llvm::Triple::mips64el:
+    if (tools::mips::hasMipsAbiArg(Args, "n32") ||
+        T.getEnvironment() == llvm::Triple::GNUABIN32)
+      return "elf32ltsmipn32";
+    return "elf64ltsmip";
+  case llvm::Triple::systemz:
+    return "elf64_s390";
+  case llvm::Triple::x86_64:
+    if (T.getEnvironment() == llvm::Triple::GNUX32)
+      return "elf32_x86_64";
+    return "elf_x86_64";
+  default:
+    return nullptr;
+  }
+}
+
+static bool getPIE(const ArgList &Args, const toolchains::Linux &ToolChain) {
+  if (Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_static) ||
+      Args.hasArg(options::OPT_r) || Args.hasArg(options::OPT_static_pie))
+    return false;
+
+  Arg *A = Args.getLastArg(options::OPT_pie, options::OPT_no_pie,
+                           options::OPT_nopie);
+  if (!A)
+    return ToolChain.isPIEDefault();
+  return A->getOption().matches(options::OPT_pie);
+}
+
+static bool getStaticPIE(const ArgList &Args,
+                         const toolchains::Linux &ToolChain) {
+  bool HasStaticPIE = Args.hasArg(options::OPT_static_pie);
+  // -no-pie is an alias for -nopie. So, handling -nopie takes care of
+  // -no-pie as well.
+  if (HasStaticPIE && Args.hasArg(options::OPT_nopie)) {
+    const Driver &D = ToolChain.getDriver();
+    const llvm::opt::OptTable &Opts = D.getOpts();
+    const char *StaticPIEName = Opts.getOptionName(options::OPT_static_pie);
+    const char *NoPIEName = Opts.getOptionName(options::OPT_nopie);
+    D.Diag(diag::err_drv_cannot_mix_options) << StaticPIEName << NoPIEName;
+  }
+  return HasStaticPIE;
+}
+
+static bool getStatic(const ArgList &Args) {
+  return Args.hasArg(options::OPT_static) &&
+      !Args.hasArg(options::OPT_static_pie);
+}
+
+void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
+                                           const InputInfo &Output,
+                                           const InputInfoList &Inputs,
+                                           const ArgList &Args,
+                                           const char *LinkingOutput) const {
+  const toolchains::Linux &ToolChain =
+      static_cast<const toolchains::Linux &>(getToolChain());
+  const Driver &D = ToolChain.getDriver();
+
+  const llvm::Triple &Triple = getToolChain().getEffectiveTriple();
+
+  const llvm::Triple::ArchType Arch = ToolChain.getArch();
+  const bool isAndroid = ToolChain.getTriple().isAndroid();
+  const bool IsIAMCU = ToolChain.getTriple().isOSIAMCU();
+  const bool IsPIE = getPIE(Args, ToolChain);
+  const bool IsStaticPIE = getStaticPIE(Args, ToolChain);
+  const bool IsStatic = getStatic(Args);
+  const bool HasCRTBeginEndFiles =
+      ToolChain.getTriple().hasEnvironment() ||
+      (ToolChain.getTriple().getVendor() != llvm::Triple::MipsTechnologies);
+
+  ArgStringList CmdArgs;
+
+  // Silence warning for "clang -g foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_g_Group);
+  // and "clang -emit-llvm foo.o -o foo"
+  Args.ClaimAllArgs(options::OPT_emit_llvm);
+  // and for "clang -w foo.o -o foo". Other warning options are already
+  // handled somewhere else.
+  Args.ClaimAllArgs(options::OPT_w);
+
+  if (!D.SysRoot.empty())
+    CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
+
+  if (IsPIE)
+    CmdArgs.push_back("-pie");
+
+  if (IsStaticPIE) {
+    CmdArgs.push_back("-static");
+    CmdArgs.push_back("-pie");
+    CmdArgs.push_back("--no-dynamic-linker");
+    CmdArgs.push_back("-z");
+    CmdArgs.push_back("text");
+  }
+
+  if (ToolChain.isNoExecStackDefault()) {
+    CmdArgs.push_back("-z");
+    CmdArgs.push_back("noexecstack");
+  }
+
+  if (Args.hasArg(options::OPT_rdynamic))
+    CmdArgs.push_back("-export-dynamic");
+
+  if (Args.hasArg(options::OPT_s))
+    CmdArgs.push_back("-s");
+
+  if (Triple.isARM() || Triple.isThumb() || Triple.isAArch64()) {
+    bool IsBigEndian = isArmBigEndian(Triple, Args);
+    if (IsBigEndian)
+      arm::appendBE8LinkFlag(Args, CmdArgs, Triple);
+    IsBigEndian = IsBigEndian || Arch == llvm::Triple::aarch64_be;
+    CmdArgs.push_back(IsBigEndian ? "-EB" : "-EL");
+  }
+
+  // Most Android ARM64 targets should enable the linker fix for erratum
+  // 843419. Only non-Cortex-A53 devices are allowed to skip this flag.
+  if (Arch == llvm::Triple::aarch64 && isAndroid) {
+    std::string CPU = getCPUName(Args, Triple);
+    if (CPU.empty() || CPU == "generic" || CPU == "cortex-a53")
+      CmdArgs.push_back("--fix-cortex-a53-843419");
+  }
+
+  // Android does not allow shared text relocations. Emit a warning if the
+  // user's code contains any.
+  if (isAndroid)
+      CmdArgs.push_back("--warn-shared-textrel");
+
+  for (const auto &Opt : ToolChain.ExtraOpts)
+    CmdArgs.push_back(Opt.c_str());
+
+  CmdArgs.push_back("--eh-frame-hdr");
+
+  if (const char *LDMOption = getLDMOption(ToolChain.getTriple(), Args)) {
+    CmdArgs.push_back("-m");
+    CmdArgs.push_back(LDMOption);
+  } else {
+    D.Diag(diag::err_target_unknown_triple) << Triple.str();
+    return;
+  }
+
+  if (IsStatic) {
+    if (Arch == llvm::Triple::arm || Arch == llvm::Triple::armeb ||
+        Arch == llvm::Triple::thumb || Arch == llvm::Triple::thumbeb)
+      CmdArgs.push_back("-Bstatic");
+    else
+      CmdArgs.push_back("-static");
+  } else if (Args.hasArg(options::OPT_shared)) {
+    CmdArgs.push_back("-shared");
+  }
+
+  if (!IsStatic) {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+
+    if (!Args.hasArg(options::OPT_shared) && !IsStaticPIE) {
+      const std::string Loader =
+          D.DyldPrefix + ToolChain.getDynamicLinker(Args);
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back(Args.MakeArgString(Loader));
+    }
+  }
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
+    if (!isAndroid && !IsIAMCU) {
+      const char *crt1 = nullptr;
+      if (!Args.hasArg(options::OPT_shared)) {
+        if (Args.hasArg(options::OPT_pg))
+          crt1 = "gcrt1.o";
+        else if (IsPIE)
+          crt1 = "Scrt1.o";
+        else if (IsStaticPIE)
+          crt1 = "rcrt1.o";
+        else
+          crt1 = "crt1.o";
+      }
+      if (crt1)
+        CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crt1)));
+
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crti.o")));
+    }
+
+    if (IsIAMCU)
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt0.o")));
+    else if (HasCRTBeginEndFiles) {
+      std::string P;
+      if (ToolChain.GetRuntimeLibType(Args) == ToolChain::RLT_CompilerRT &&
+          !isAndroid) {
+        std::string crtbegin = ToolChain.getCompilerRT(Args, "crtbegin",
+                                                       ToolChain::FT_Object);
+        if (ToolChain.getVFS().exists(crtbegin))
+          P = crtbegin;
+      }
+      if (P.empty()) {
+        const char *crtbegin;
+        if (IsStatic)
+          crtbegin = isAndroid ? "crtbegin_static.o" : "crtbeginT.o";
+        else if (Args.hasArg(options::OPT_shared))
+          crtbegin = isAndroid ? "crtbegin_so.o" : "crtbeginS.o";
+        else if (IsPIE || IsStaticPIE)
+          crtbegin = isAndroid ? "crtbegin_dynamic.o" : "crtbeginS.o";
+        else
+          crtbegin = isAndroid ? "crtbegin_dynamic.o" : "crtbegin.o";
+        P = ToolChain.GetFilePath(crtbegin);
+      }
+      CmdArgs.push_back(Args.MakeArgString(P));
+    }
+
+    // Add crtfastmath.o if available and fast math is enabled.
+    ToolChain.AddFastMathRuntimeIfAvailable(Args, CmdArgs);
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_u);
+
+  ToolChain.AddFilePathLibArgs(Args, CmdArgs);
+
+  if (D.isUsingLTO()) {
+    assert(!Inputs.empty() && "Must have at least one input.");
+    AddGoldPlugin(ToolChain, Args, CmdArgs, Output, Inputs[0],
+                  D.getLTOMode() == LTOK_Thin);
+  }
+
+  if (Args.hasArg(options::OPT_Z_Xlinker__no_demangle))
+    CmdArgs.push_back("--no-demangle");
+
+  bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
+  bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
+  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
+  // The profile runtime also needs access to system libraries.
+  getToolChain().addProfileRTLibs(Args, CmdArgs);
+
+  if (D.CCCIsCXX() &&
+      !Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
+    if (ToolChain.ShouldLinkCXXStdlib(Args)) {
+      bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
+                                 !Args.hasArg(options::OPT_static);
+      if (OnlyLibstdcxxStatic)
+        CmdArgs.push_back("-Bstatic");
+      ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
+      if (OnlyLibstdcxxStatic)
+        CmdArgs.push_back("-Bdynamic");
+    }
+    CmdArgs.push_back("-lm");
+  }
+  // Silence warnings when linking C code with a C++ '-stdlib' argument.
+  Args.ClaimAllArgs(options::OPT_stdlib_EQ);
+
+  if (!Args.hasArg(options::OPT_nostdlib)) {
+    if (!Args.hasArg(options::OPT_nodefaultlibs)) {
+      if (IsStatic || IsStaticPIE)
+        CmdArgs.push_back("--start-group");
+
+      if (NeedsSanitizerDeps)
+        linkSanitizerRuntimeDeps(ToolChain, CmdArgs);
+
+      if (NeedsXRayDeps)
+        linkXRayRuntimeDeps(ToolChain, CmdArgs);
+
+      bool WantPthread = Args.hasArg(options::OPT_pthread) ||
+                         Args.hasArg(options::OPT_pthreads);
+
+      // Use the static OpenMP runtime with -static-openmp
+      bool StaticOpenMP = Args.hasArg(options::OPT_static_openmp) &&
+                          !Args.hasArg(options::OPT_static);
+
+      // FIXME: Only pass GompNeedsRT = true for platforms with libgomp that
+      // require librt. Most modern Linux platforms do, but some may not.
+      if (addOpenMPRuntime(CmdArgs, ToolChain, Args, StaticOpenMP,
+                           JA.isHostOffloading(Action::OFK_OpenMP),
+                           /* GompNeedsRT= */ true))
+        // OpenMP runtimes implies pthreads when using the GNU toolchain.
+        // FIXME: Does this really make sense for all GNU toolchains?
+        WantPthread = true;
+
+      AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+
+      if (WantPthread && !isAndroid)
+        CmdArgs.push_back("-lpthread");
+
+      if (Args.hasArg(options::OPT_fsplit_stack))
+        CmdArgs.push_back("--wrap=pthread_create");
+
+      if (!Args.hasArg(options::OPT_nolibc))
+        CmdArgs.push_back("-lc");
+
+      // Add IAMCU specific libs, if needed.
+      if (IsIAMCU)
+        CmdArgs.push_back("-lgloss");
+
+      if (IsStatic || IsStaticPIE)
+        CmdArgs.push_back("--end-group");
+      else
+        AddRunTimeLibs(ToolChain, D, CmdArgs, Args);
+
+      // Add IAMCU specific libs (outside the group), if needed.
+      if (IsIAMCU) {
+        CmdArgs.push_back("--as-needed");
+        CmdArgs.push_back("-lsoftfp");
+        CmdArgs.push_back("--no-as-needed");
+      }
+    }
+
+    if (!Args.hasArg(options::OPT_nostartfiles) && !IsIAMCU) {
+      if (HasCRTBeginEndFiles) {
+        std::string P;
+        if (ToolChain.GetRuntimeLibType(Args) == ToolChain::RLT_CompilerRT &&
+            !isAndroid) {
+          std::string crtend = ToolChain.getCompilerRT(Args, "crtend",
+                                                       ToolChain::FT_Object);
+          if (ToolChain.getVFS().exists(crtend))
+            P = crtend;
+        }
+        if (P.empty()) {
+          const char *crtend;
+          if (Args.hasArg(options::OPT_shared))
+            crtend = isAndroid ? "crtend_so.o" : "crtendS.o";
+          else if (IsPIE || IsStaticPIE)
+            crtend = isAndroid ? "crtend_android.o" : "crtendS.o";
+          else
+            crtend = isAndroid ? "crtend_android.o" : "crtend.o";
+          P = ToolChain.GetFilePath(crtend);
+        }
+        CmdArgs.push_back(Args.MakeArgString(P));
+      }
+      if (!isAndroid)
+        CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
+    }
+  }
+
+  // Add HIP offloading linker script args if required.
+  AddHIPLinkerScript(getToolChain(), C, Output, Inputs, Args, CmdArgs, JA,
+                     *this);
+
+  const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
+  C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+}
+
+void tools::gnutools::Assembler::ConstructJob(Compilation &C,
+                                              const JobAction &JA,
+                                              const InputInfo &Output,
+                                              const InputInfoList &Inputs,
+                                              const ArgList &Args,
+                                              const char *LinkingOutput) const {
+  const auto &D = getToolChain().getDriver();
+
+  claimNoWarnArgs(Args);
+
+  ArgStringList CmdArgs;
+
+  llvm::Reloc::Model RelocationModel;
+  unsigned PICLevel;
+  bool IsPIE;
+  std::tie(RelocationModel, PICLevel, IsPIE) =
+      ParsePICArgs(getToolChain(), Args);
+
+  if (const Arg *A = Args.getLastArg(options::OPT_gz, options::OPT_gz_EQ)) {
+    if (A->getOption().getID() == options::OPT_gz) {
+      CmdArgs.push_back("--compress-debug-sections");
+    } else {
+      StringRef Value = A->getValue();
+      if (Value == "none" || Value == "zlib" || Value == "zlib-gnu") {
+        CmdArgs.push_back(
+            Args.MakeArgString("--compress-debug-sections=" + Twine(Value)));
+      } else {
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Value;
+      }
+    }
+  }
+
+  if (getToolChain().isNoExecStackDefault()) {
+      CmdArgs.push_back("--noexecstack");
+  }
+
+  switch (getToolChain().getArch()) {
+  default:
+    break;
+  // Add --32/--64 to make sure we get the format we want.
+  // This is incomplete
+  case llvm::Triple::x86:
+    CmdArgs.push_back("--32");
+    break;
+  case llvm::Triple::x86_64:
+    if (getToolChain().getTriple().getEnvironment() == llvm::Triple::GNUX32)
+      CmdArgs.push_back("--x32");
+    else
+      CmdArgs.push_back("--64");
+    break;
+  case llvm::Triple::ppc: {
+    CmdArgs.push_back("-a32");
+    CmdArgs.push_back("-mppc");
+    CmdArgs.push_back(
+      ppc::getPPCAsmModeForCPU(getCPUName(Args, getToolChain().getTriple())));
+    break;
+  }
+  case llvm::Triple::ppc64: {
+    CmdArgs.push_back("-a64");
+    CmdArgs.push_back("-mppc64");
+    CmdArgs.push_back(
+      ppc::getPPCAsmModeForCPU(getCPUName(Args, getToolChain().getTriple())));
+    break;
+  }
+  case llvm::Triple::ppc64le: {
+    CmdArgs.push_back("-a64");
+    CmdArgs.push_back("-mppc64");
+    CmdArgs.push_back("-mlittle-endian");
+    CmdArgs.push_back(
+      ppc::getPPCAsmModeForCPU(getCPUName(Args, getToolChain().getTriple())));
+    break;
+  }
+  case llvm::Triple::riscv32:
+  case llvm::Triple::riscv64: {
+    StringRef ABIName = riscv::getRISCVABI(Args, getToolChain().getTriple());
+    CmdArgs.push_back("-mabi");
+    CmdArgs.push_back(ABIName.data());
+    StringRef MArchName = riscv::getRISCVArch(Args, getToolChain().getTriple());
+    CmdArgs.push_back("-march");
+    CmdArgs.push_back(MArchName.data());
+    break;
+  }
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel: {
+    CmdArgs.push_back("-32");
+    std::string CPU = getCPUName(Args, getToolChain().getTriple());
+    CmdArgs.push_back(
+        sparc::getSparcAsmModeForCPU(CPU, getToolChain().getTriple()));
+    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
+    break;
+  }
+  case llvm::Triple::sparcv9: {
+    CmdArgs.push_back("-64");
+    std::string CPU = getCPUName(Args, getToolChain().getTriple());
+    CmdArgs.push_back(
+        sparc::getSparcAsmModeForCPU(CPU, getToolChain().getTriple()));
+    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
+    break;
+  }
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb: {
+    const llvm::Triple &Triple2 = getToolChain().getTriple();
+    CmdArgs.push_back(isArmBigEndian(Triple2, Args) ? "-EB" : "-EL");
+    switch (Triple2.getSubArch()) {
+    case llvm::Triple::ARMSubArch_v7:
+      CmdArgs.push_back("-mfpu=neon");
+      break;
+    case llvm::Triple::ARMSubArch_v8:
+      CmdArgs.push_back("-mfpu=crypto-neon-fp-armv8");
+      break;
+    default:
+      break;
+    }
+
+    switch (arm::getARMFloatABI(getToolChain(), Args)) {
+    case arm::FloatABI::Invalid: llvm_unreachable("must have an ABI!");
+    case arm::FloatABI::Soft:
+      CmdArgs.push_back(Args.MakeArgString("-mfloat-abi=soft"));
+      break;
+    case arm::FloatABI::SoftFP:
+      CmdArgs.push_back(Args.MakeArgString("-mfloat-abi=softfp"));
+      break;
+    case arm::FloatABI::Hard:
+      CmdArgs.push_back(Args.MakeArgString("-mfloat-abi=hard"));
+      break;
+    }
+
+    Args.AddLastArg(CmdArgs, options::OPT_march_EQ);
+    normalizeCPUNamesForAssembler(Args, CmdArgs);
+
+    Args.AddLastArg(CmdArgs, options::OPT_mfpu_EQ);
+    break;
+  }
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be: {
+    CmdArgs.push_back(
+        getToolChain().getArch() == llvm::Triple::aarch64_be ? "-EB" : "-EL");
+    Args.AddLastArg(CmdArgs, options::OPT_march_EQ);
+    normalizeCPUNamesForAssembler(Args, CmdArgs);
+
+    break;
+  }
+  case llvm::Triple::mips:
+  case llvm::Triple::mipsel:
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el: {
+    StringRef CPUName;
+    StringRef ABIName;
+    mips::getMipsCPUAndABI(Args, getToolChain().getTriple(), CPUName, ABIName);
+    ABIName = mips::getGnuCompatibleMipsABIName(ABIName);
+
+    CmdArgs.push_back("-march");
+    CmdArgs.push_back(CPUName.data());
+
+    CmdArgs.push_back("-mabi");
+    CmdArgs.push_back(ABIName.data());
+
+    // -mno-shared should be emitted unless -fpic, -fpie, -fPIC, -fPIE,
+    // or -mshared (not implemented) is in effect.
+    if (RelocationModel == llvm::Reloc::Static)
+      CmdArgs.push_back("-mno-shared");
+
+    // LLVM doesn't support -mplt yet and acts as if it is always given.
+    // However, -mplt has no effect with the N64 ABI.
+    if (ABIName != "64" && !Args.hasArg(options::OPT_mno_abicalls))
+      CmdArgs.push_back("-call_nonpic");
+
+    if (getToolChain().getTriple().isLittleEndian())
+      CmdArgs.push_back("-EL");
+    else
+      CmdArgs.push_back("-EB");
+
+    if (Arg *A = Args.getLastArg(options::OPT_mnan_EQ)) {
+      if (StringRef(A->getValue()) == "2008")
+        CmdArgs.push_back(Args.MakeArgString("-mnan=2008"));
+    }
+
+    // Add the last -mfp32/-mfpxx/-mfp64 or -mfpxx if it is enabled by default.
+    if (Arg *A = Args.getLastArg(options::OPT_mfp32, options::OPT_mfpxx,
+                                 options::OPT_mfp64)) {
+      A->claim();
+      A->render(Args, CmdArgs);
+    } else if (mips::shouldUseFPXX(
+                   Args, getToolChain().getTriple(), CPUName, ABIName,
+                   mips::getMipsFloatABI(getToolChain().getDriver(), Args,
+                                         getToolChain().getTriple())))
+      CmdArgs.push_back("-mfpxx");
+
+    // Pass on -mmips16 or -mno-mips16. However, the assembler equivalent of
+    // -mno-mips16 is actually -no-mips16.
+    if (Arg *A =
+            Args.getLastArg(options::OPT_mips16, options::OPT_mno_mips16)) {
+      if (A->getOption().matches(options::OPT_mips16)) {
+        A->claim();
+        A->render(Args, CmdArgs);
+      } else {
+        A->claim();
+        CmdArgs.push_back("-no-mips16");
+      }
+    }
+
+    Args.AddLastArg(CmdArgs, options::OPT_mmicromips,
+                    options::OPT_mno_micromips);
+    Args.AddLastArg(CmdArgs, options::OPT_mdsp, options::OPT_mno_dsp);
+    Args.AddLastArg(CmdArgs, options::OPT_mdspr2, options::OPT_mno_dspr2);
+
+    if (Arg *A = Args.getLastArg(options::OPT_mmsa, options::OPT_mno_msa)) {
+      // Do not use AddLastArg because not all versions of MIPS assembler
+      // support -mmsa / -mno-msa options.
+      if (A->getOption().matches(options::OPT_mmsa))
+        CmdArgs.push_back(Args.MakeArgString("-mmsa"));
+    }
+
+    Args.AddLastArg(CmdArgs, options::OPT_mhard_float,
+                    options::OPT_msoft_float);
+
+    Args.AddLastArg(CmdArgs, options::OPT_mdouble_float,
+                    options::OPT_msingle_float);
+
+    Args.AddLastArg(CmdArgs, options::OPT_modd_spreg,
+                    options::OPT_mno_odd_spreg);
+
+    AddAssemblerKPIC(getToolChain(), Args, CmdArgs);
+    break;
+  }
+  case llvm::Triple::systemz: {
+    // Always pass an -march option, since our default of z10 is later
+    // than the GNU assembler's default.
+    std::string CPUName = systemz::getSystemZTargetCPU(Args);
+    CmdArgs.push_back(Args.MakeArgString("-march=" + CPUName));
+    break;
+  }
+  }
+
+  for (const Arg *A : Args.filtered(options::OPT_ffile_prefix_map_EQ,
+                                    options::OPT_fdebug_prefix_map_EQ)) {
+    StringRef Map = A->getValue();
+    if (Map.find('=') == StringRef::npos)
+      D.Diag(diag::err_drv_invalid_argument_to_option)
+          << Map << A->getOption().getName();
+    else {
+      CmdArgs.push_back(Args.MakeArgString("--debug-prefix-map"));
+      CmdArgs.push_back(Args.MakeArgString(Map));
+    }
+    A->claim();
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_I);
+  Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA, options::OPT_Xassembler);
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+
+  for (const auto &II : Inputs)
+    CmdArgs.push_back(II.getFilename());
+
+  const char *Exec = Args.MakeArgString(getToolChain().GetProgramPath("as"));
+  C.addCommand(std::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
+
+  // Handle the debug info splitting at object creation time if we're
+  // creating an object.
+  // TODO: Currently only works on linux with newer objcopy.
+  if (Args.hasArg(options::OPT_gsplit_dwarf) &&
+      getToolChain().getTriple().isOSLinux())
+    SplitDebugInfo(getToolChain(), C, *this, JA, Args, Output,
+                   SplitDebugName(Args, Inputs[0], Output));
+}
+
+namespace {
+// Filter to remove Multilibs that don't exist as a suffix to Path
+class FilterNonExistent {
+  StringRef Base, File;
+  llvm::vfs::FileSystem &VFS;
+
+public:
+  FilterNonExistent(StringRef Base, StringRef File, llvm::vfs::FileSystem &VFS)
+      : Base(Base), File(File), VFS(VFS) {}
+  bool operator()(const Multilib &M) {
+    return !VFS.exists(Base + M.gccSuffix() + File);
+  }
+};
+} // end anonymous namespace
+
+static bool isSoftFloatABI(const ArgList &Args) {
+  Arg *A = Args.getLastArg(options::OPT_msoft_float, options::OPT_mhard_float,
+                           options::OPT_mfloat_abi_EQ);
+  if (!A)
+    return false;
+
+  return A->getOption().matches(options::OPT_msoft_float) ||
+         (A->getOption().matches(options::OPT_mfloat_abi_EQ) &&
+          A->getValue() == StringRef("soft"));
+}
+
+static bool isArmOrThumbArch(llvm::Triple::ArchType Arch) {
+  return Arch == llvm::Triple::arm || Arch == llvm::Triple::thumb;
+}
+
+static bool isMipsEL(llvm::Triple::ArchType Arch) {
+  return Arch == llvm::Triple::mipsel || Arch == llvm::Triple::mips64el;
+}
+
+static bool isMips16(const ArgList &Args) {
+  Arg *A = Args.getLastArg(options::OPT_mips16, options::OPT_mno_mips16);
+  return A && A->getOption().matches(options::OPT_mips16);
+}
+
+static bool isMicroMips(const ArgList &Args) {
+  Arg *A = Args.getLastArg(options::OPT_mmicromips, options::OPT_mno_micromips);
+  return A && A->getOption().matches(options::OPT_mmicromips);
+}
+
+static bool isMSP430(llvm::Triple::ArchType Arch) {
+  return Arch == llvm::Triple::msp430;
+}
+
+static Multilib makeMultilib(StringRef commonSuffix) {
+  return Multilib(commonSuffix, commonSuffix, commonSuffix);
+}
+
+static bool findMipsCsMultilibs(const Multilib::flags_list &Flags,
+                                FilterNonExistent &NonExistent,
+                                DetectedMultilibs &Result) {
+  // Check for Code Sourcery toolchain multilibs
+  MultilibSet CSMipsMultilibs;
+  {
+    auto MArchMips16 = makeMultilib("/mips16").flag("+m32").flag("+mips16");
+
+    auto MArchMicroMips =
+        makeMultilib("/micromips").flag("+m32").flag("+mmicromips");
+
+    auto MArchDefault = makeMultilib("").flag("-mips16").flag("-mmicromips");
+
+    auto UCLibc = makeMultilib("/uclibc").flag("+muclibc");
+
+    auto SoftFloat = makeMultilib("/soft-float").flag("+msoft-float");
+
+    auto Nan2008 = makeMultilib("/nan2008").flag("+mnan=2008");
+
+    auto DefaultFloat =
+        makeMultilib("").flag("-msoft-float").flag("-mnan=2008");
+
+    auto BigEndian = makeMultilib("").flag("+EB").flag("-EL");
+
+    auto LittleEndian = makeMultilib("/el").flag("+EL").flag("-EB");
+
+    // Note that this one's osSuffix is ""
+    auto MAbi64 = makeMultilib("")
+                      .gccSuffix("/64")
+                      .includeSuffix("/64")
+                      .flag("+mabi=n64")
+                      .flag("-mabi=n32")
+                      .flag("-m32");
+
+    CSMipsMultilibs =
+        MultilibSet()
+            .Either(MArchMips16, MArchMicroMips, MArchDefault)
+            .Maybe(UCLibc)
+            .Either(SoftFloat, Nan2008, DefaultFloat)
+            .FilterOut("/micromips/nan2008")
+            .FilterOut("/mips16/nan2008")
+            .Either(BigEndian, LittleEndian)
+            .Maybe(MAbi64)
+            .FilterOut("/mips16.*/64")
+            .FilterOut("/micromips.*/64")
+            .FilterOut(NonExistent)
+            .setIncludeDirsCallback([](const Multilib &M) {
+              std::vector<std::string> Dirs({"/include"});
+              if (StringRef(M.includeSuffix()).startswith("/uclibc"))
+                Dirs.push_back(
+                    "/../../../../mips-linux-gnu/libc/uclibc/usr/include");
+              else
+                Dirs.push_back("/../../../../mips-linux-gnu/libc/usr/include");
+              return Dirs;
+            });
+  }
+
+  MultilibSet DebianMipsMultilibs;
+  {
+    Multilib MAbiN32 =
+        Multilib().gccSuffix("/n32").includeSuffix("/n32").flag("+mabi=n32");
+
+    Multilib M64 = Multilib()
+                       .gccSuffix("/64")
+                       .includeSuffix("/64")
+                       .flag("+m64")
+                       .flag("-m32")
+                       .flag("-mabi=n32");
+
+    Multilib M32 = Multilib().flag("-m64").flag("+m32").flag("-mabi=n32");
+
+    DebianMipsMultilibs =
+        MultilibSet().Either(M32, M64, MAbiN32).FilterOut(NonExistent);
+  }
+
+  // Sort candidates. Toolchain that best meets the directories tree goes first.
+  // Then select the first toolchains matches command line flags.
+  MultilibSet *Candidates[] = {&CSMipsMultilibs, &DebianMipsMultilibs};
+  if (CSMipsMultilibs.size() < DebianMipsMultilibs.size())
+    std::iter_swap(Candidates, Candidates + 1);
+  for (const MultilibSet *Candidate : Candidates) {
+    if (Candidate->select(Flags, Result.SelectedMultilib)) {
+      if (Candidate == &DebianMipsMultilibs)
+        Result.BiarchSibling = Multilib();
+      Result.Multilibs = *Candidate;
+      return true;
+    }
+  }
+  return false;
+}
+
+static bool findMipsAndroidMultilibs(llvm::vfs::FileSystem &VFS, StringRef Path,
+                                     const Multilib::flags_list &Flags,
+                                     FilterNonExistent &NonExistent,
+                                     DetectedMultilibs &Result) {
+
+  MultilibSet AndroidMipsMultilibs =
+      MultilibSet()
+          .Maybe(Multilib("/mips-r2").flag("+march=mips32r2"))
+          .Maybe(Multilib("/mips-r6").flag("+march=mips32r6"))
+          .FilterOut(NonExistent);
+
+  MultilibSet AndroidMipselMultilibs =
+      MultilibSet()
+          .Either(Multilib().flag("+march=mips32"),
+                  Multilib("/mips-r2", "", "/mips-r2").flag("+march=mips32r2"),
+                  Multilib("/mips-r6", "", "/mips-r6").flag("+march=mips32r6"))
+          .FilterOut(NonExistent);
+
+  MultilibSet AndroidMips64elMultilibs =
+      MultilibSet()
+          .Either(
+              Multilib().flag("+march=mips64r6"),
+              Multilib("/32/mips-r1", "", "/mips-r1").flag("+march=mips32"),
+              Multilib("/32/mips-r2", "", "/mips-r2").flag("+march=mips32r2"),
+              Multilib("/32/mips-r6", "", "/mips-r6").flag("+march=mips32r6"))
+          .FilterOut(NonExistent);
+
+  MultilibSet *MS = &AndroidMipsMultilibs;
+  if (VFS.exists(Path + "/mips-r6"))
+    MS = &AndroidMipselMultilibs;
+  else if (VFS.exists(Path + "/32"))
+    MS = &AndroidMips64elMultilibs;
+  if (MS->select(Flags, Result.SelectedMultilib)) {
+    Result.Multilibs = *MS;
+    return true;
+  }
+  return false;
+}
+
+static bool findMipsMuslMultilibs(const Multilib::flags_list &Flags,
+                                  FilterNonExistent &NonExistent,
+                                  DetectedMultilibs &Result) {
+  // Musl toolchain multilibs
+  MultilibSet MuslMipsMultilibs;
+  {
+    auto MArchMipsR2 = makeMultilib("")
+                           .osSuffix("/mips-r2-hard-musl")
+                           .flag("+EB")
+                           .flag("-EL")
+                           .flag("+march=mips32r2");
+
+    auto MArchMipselR2 = makeMultilib("/mipsel-r2-hard-musl")
+                             .flag("-EB")
+                             .flag("+EL")
+                             .flag("+march=mips32r2");
+
+    MuslMipsMultilibs = MultilibSet().Either(MArchMipsR2, MArchMipselR2);
+
+    // Specify the callback that computes the include directories.
+    MuslMipsMultilibs.setIncludeDirsCallback([](const Multilib &M) {
+      return std::vector<std::string>(
+          {"/../sysroot" + M.osSuffix() + "/usr/include"});
+    });
+  }
+  if (MuslMipsMultilibs.select(Flags, Result.SelectedMultilib)) {
+    Result.Multilibs = MuslMipsMultilibs;
+    return true;
+  }
+  return false;
+}
+
+static bool findMipsMtiMultilibs(const Multilib::flags_list &Flags,
+                                 FilterNonExistent &NonExistent,
+                                 DetectedMultilibs &Result) {
+  // CodeScape MTI toolchain v1.2 and early.
+  MultilibSet MtiMipsMultilibsV1;
+  {
+    auto MArchMips32 = makeMultilib("/mips32")
+                           .flag("+m32")
+                           .flag("-m64")
+                           .flag("-mmicromips")
+                           .flag("+march=mips32");
+
+    auto MArchMicroMips = makeMultilib("/micromips")
+                              .flag("+m32")
+                              .flag("-m64")
+                              .flag("+mmicromips");
+
+    auto MArchMips64r2 = makeMultilib("/mips64r2")
+                             .flag("-m32")
+                             .flag("+m64")
+                             .flag("+march=mips64r2");
+
+    auto MArchMips64 = makeMultilib("/mips64").flag("-m32").flag("+m64").flag(
+        "-march=mips64r2");
+
+    auto MArchDefault = makeMultilib("")
+                            .flag("+m32")
+                            .flag("-m64")
+                            .flag("-mmicromips")
+                            .flag("+march=mips32r2");
+
+    auto Mips16 = makeMultilib("/mips16").flag("+mips16");
+
+    auto UCLibc = makeMultilib("/uclibc").flag("+muclibc");
+
+    auto MAbi64 =
+        makeMultilib("/64").flag("+mabi=n64").flag("-mabi=n32").flag("-m32");
+
+    auto BigEndian = makeMultilib("").flag("+EB").flag("-EL");
+
+    auto LittleEndian = makeMultilib("/el").flag("+EL").flag("-EB");
+
+    auto SoftFloat = makeMultilib("/sof").flag("+msoft-float");
+
+    auto Nan2008 = makeMultilib("/nan2008").flag("+mnan=2008");
+
+    MtiMipsMultilibsV1 =
+        MultilibSet()
+            .Either(MArchMips32, MArchMicroMips, MArchMips64r2, MArchMips64,
+                    MArchDefault)
+            .Maybe(UCLibc)
+            .Maybe(Mips16)
+            .FilterOut("/mips64/mips16")
+            .FilterOut("/mips64r2/mips16")
+            .FilterOut("/micromips/mips16")
+            .Maybe(MAbi64)
+            .FilterOut("/micromips/64")
+            .FilterOut("/mips32/64")
+            .FilterOut("^/64")
+            .FilterOut("/mips16/64")
+            .Either(BigEndian, LittleEndian)
+            .Maybe(SoftFloat)
+            .Maybe(Nan2008)
+            .FilterOut(".*sof/nan2008")
+            .FilterOut(NonExistent)
+            .setIncludeDirsCallback([](const Multilib &M) {
+              std::vector<std::string> Dirs({"/include"});
+              if (StringRef(M.includeSuffix()).startswith("/uclibc"))
+                Dirs.push_back("/../../../../sysroot/uclibc/usr/include");
+              else
+                Dirs.push_back("/../../../../sysroot/usr/include");
+              return Dirs;
+            });
+  }
+
+  // CodeScape IMG toolchain starting from v1.3.
+  MultilibSet MtiMipsMultilibsV2;
+  {
+    auto BeHard = makeMultilib("/mips-r2-hard")
+                      .flag("+EB")
+                      .flag("-msoft-float")
+                      .flag("-mnan=2008")
+                      .flag("-muclibc");
+    auto BeSoft = makeMultilib("/mips-r2-soft")
+                      .flag("+EB")
+                      .flag("+msoft-float")
+                      .flag("-mnan=2008");
+    auto ElHard = makeMultilib("/mipsel-r2-hard")
+                      .flag("+EL")
+                      .flag("-msoft-float")
+                      .flag("-mnan=2008")
+                      .flag("-muclibc");
+    auto ElSoft = makeMultilib("/mipsel-r2-soft")
+                      .flag("+EL")
+                      .flag("+msoft-float")
+                      .flag("-mnan=2008")
+                      .flag("-mmicromips");
+    auto BeHardNan = makeMultilib("/mips-r2-hard-nan2008")
+                         .flag("+EB")
+                         .flag("-msoft-float")
+                         .flag("+mnan=2008")
+                         .flag("-muclibc");
+    auto ElHardNan = makeMultilib("/mipsel-r2-hard-nan2008")
+                         .flag("+EL")
+                         .flag("-msoft-float")
+                         .flag("+mnan=2008")
+                         .flag("-muclibc")
+                         .flag("-mmicromips");
+    auto BeHardNanUclibc = makeMultilib("/mips-r2-hard-nan2008-uclibc")
+                               .flag("+EB")
+                               .flag("-msoft-float")
+                               .flag("+mnan=2008")
+                               .flag("+muclibc");
+    auto ElHardNanUclibc = makeMultilib("/mipsel-r2-hard-nan2008-uclibc")
+                               .flag("+EL")
+                               .flag("-msoft-float")
+                               .flag("+mnan=2008")
+                               .flag("+muclibc");
+    auto BeHardUclibc = makeMultilib("/mips-r2-hard-uclibc")
+                            .flag("+EB")
+                            .flag("-msoft-float")
+                            .flag("-mnan=2008")
+                            .flag("+muclibc");
+    auto ElHardUclibc = makeMultilib("/mipsel-r2-hard-uclibc")
+                            .flag("+EL")
+                            .flag("-msoft-float")
+                            .flag("-mnan=2008")
+                            .flag("+muclibc");
+    auto ElMicroHardNan = makeMultilib("/micromipsel-r2-hard-nan2008")
+                              .flag("+EL")
+                              .flag("-msoft-float")
+                              .flag("+mnan=2008")
+                              .flag("+mmicromips");
+    auto ElMicroSoft = makeMultilib("/micromipsel-r2-soft")
+                           .flag("+EL")
+                           .flag("+msoft-float")
+                           .flag("-mnan=2008")
+                           .flag("+mmicromips");
+
+    auto O32 =
+        makeMultilib("/lib").osSuffix("").flag("-mabi=n32").flag("-mabi=n64");
+    auto N32 =
+        makeMultilib("/lib32").osSuffix("").flag("+mabi=n32").flag("-mabi=n64");
+    auto N64 =
+        makeMultilib("/lib64").osSuffix("").flag("-mabi=n32").flag("+mabi=n64");
+
+    MtiMipsMultilibsV2 =
+        MultilibSet()
+            .Either({BeHard, BeSoft, ElHard, ElSoft, BeHardNan, ElHardNan,
+                     BeHardNanUclibc, ElHardNanUclibc, BeHardUclibc,
+                     ElHardUclibc, ElMicroHardNan, ElMicroSoft})
+            .Either(O32, N32, N64)
+            .FilterOut(NonExistent)
+            .setIncludeDirsCallback([](const Multilib &M) {
+              return std::vector<std::string>({"/../../../../sysroot" +
+                                               M.includeSuffix() +
+                                               "/../usr/include"});
+            })
+            .setFilePathsCallback([](const Multilib &M) {
+              return std::vector<std::string>(
+                  {"/../../../../mips-mti-linux-gnu/lib" + M.gccSuffix()});
+            });
+  }
+  for (auto Candidate : {&MtiMipsMultilibsV1, &MtiMipsMultilibsV2}) {
+    if (Candidate->select(Flags, Result.SelectedMultilib)) {
+      Result.Multilibs = *Candidate;
+      return true;
+    }
+  }
+  return false;
+}
+
+static bool findMipsImgMultilibs(const Multilib::flags_list &Flags,
+                                 FilterNonExistent &NonExistent,
+                                 DetectedMultilibs &Result) {
+  // CodeScape IMG toolchain v1.2 and early.
+  MultilibSet ImgMultilibsV1;
+  {
+    auto Mips64r6 = makeMultilib("/mips64r6").flag("+m64").flag("-m32");
+
+    auto LittleEndian = makeMultilib("/el").flag("+EL").flag("-EB");
+
+    auto MAbi64 =
+        makeMultilib("/64").flag("+mabi=n64").flag("-mabi=n32").flag("-m32");
+
+    ImgMultilibsV1 =
+        MultilibSet()
+            .Maybe(Mips64r6)
+            .Maybe(MAbi64)
+            .Maybe(LittleEndian)
+            .FilterOut(NonExistent)
+            .setIncludeDirsCallback([](const Multilib &M) {
+              return std::vector<std::string>(
+                  {"/include", "/../../../../sysroot/usr/include"});
+            });
+  }
+
+  // CodeScape IMG toolchain starting from v1.3.
+  MultilibSet ImgMultilibsV2;
+  {
+    auto BeHard = makeMultilib("/mips-r6-hard")
+                      .flag("+EB")
+                      .flag("-msoft-float")
+                      .flag("-mmicromips");
+    auto BeSoft = makeMultilib("/mips-r6-soft")
+                      .flag("+EB")
+                      .flag("+msoft-float")
+                      .flag("-mmicromips");
+    auto ElHard = makeMultilib("/mipsel-r6-hard")
+                      .flag("+EL")
+                      .flag("-msoft-float")
+                      .flag("-mmicromips");
+    auto ElSoft = makeMultilib("/mipsel-r6-soft")
+                      .flag("+EL")
+                      .flag("+msoft-float")
+                      .flag("-mmicromips");
+    auto BeMicroHard = makeMultilib("/micromips-r6-hard")
+                           .flag("+EB")
+                           .flag("-msoft-float")
+                           .flag("+mmicromips");
+    auto BeMicroSoft = makeMultilib("/micromips-r6-soft")
+                           .flag("+EB")
+                           .flag("+msoft-float")
+                           .flag("+mmicromips");
+    auto ElMicroHard = makeMultilib("/micromipsel-r6-hard")
+                           .flag("+EL")
+                           .flag("-msoft-float")
+                           .flag("+mmicromips");
+    auto ElMicroSoft = makeMultilib("/micromipsel-r6-soft")
+                           .flag("+EL")
+                           .flag("+msoft-float")
+                           .flag("+mmicromips");
+
+    auto O32 =
+        makeMultilib("/lib").osSuffix("").flag("-mabi=n32").flag("-mabi=n64");
+    auto N32 =
+        makeMultilib("/lib32").osSuffix("").flag("+mabi=n32").flag("-mabi=n64");
+    auto N64 =
+        makeMultilib("/lib64").osSuffix("").flag("-mabi=n32").flag("+mabi=n64");
+
+    ImgMultilibsV2 =
+        MultilibSet()
+            .Either({BeHard, BeSoft, ElHard, ElSoft, BeMicroHard, BeMicroSoft,
+                     ElMicroHard, ElMicroSoft})
+            .Either(O32, N32, N64)
+            .FilterOut(NonExistent)
+            .setIncludeDirsCallback([](const Multilib &M) {
+              return std::vector<std::string>({"/../../../../sysroot" +
+                                               M.includeSuffix() +
+                                               "/../usr/include"});
+            })
+            .setFilePathsCallback([](const Multilib &M) {
+              return std::vector<std::string>(
+                  {"/../../../../mips-img-linux-gnu/lib" + M.gccSuffix()});
+            });
+  }
+  for (auto Candidate : {&ImgMultilibsV1, &ImgMultilibsV2}) {
+    if (Candidate->select(Flags, Result.SelectedMultilib)) {
+      Result.Multilibs = *Candidate;
+      return true;
+    }
+  }
+  return false;
+}
+
+bool clang::driver::findMIPSMultilibs(const Driver &D,
+                                      const llvm::Triple &TargetTriple,
+                                      StringRef Path, const ArgList &Args,
+                                      DetectedMultilibs &Result) {
+  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
+
+  StringRef CPUName;
+  StringRef ABIName;
+  tools::mips::getMipsCPUAndABI(Args, TargetTriple, CPUName, ABIName);
+
+  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
+
+  Multilib::flags_list Flags;
+  addMultilibFlag(TargetTriple.isMIPS32(), "m32", Flags);
+  addMultilibFlag(TargetTriple.isMIPS64(), "m64", Flags);
+  addMultilibFlag(isMips16(Args), "mips16", Flags);
+  addMultilibFlag(CPUName == "mips32", "march=mips32", Flags);
+  addMultilibFlag(CPUName == "mips32r2" || CPUName == "mips32r3" ||
+                      CPUName == "mips32r5" || CPUName == "p5600",
+                  "march=mips32r2", Flags);
+  addMultilibFlag(CPUName == "mips32r6", "march=mips32r6", Flags);
+  addMultilibFlag(CPUName == "mips64", "march=mips64", Flags);
+  addMultilibFlag(CPUName == "mips64r2" || CPUName == "mips64r3" ||
+                      CPUName == "mips64r5" || CPUName == "octeon" ||
+                      CPUName == "octeon+",
+                  "march=mips64r2", Flags);
+  addMultilibFlag(CPUName == "mips64r6", "march=mips64r6", Flags);
+  addMultilibFlag(isMicroMips(Args), "mmicromips", Flags);
+  addMultilibFlag(tools::mips::isUCLibc(Args), "muclibc", Flags);
+  addMultilibFlag(tools::mips::isNaN2008(Args, TargetTriple), "mnan=2008",
+                  Flags);
+  addMultilibFlag(ABIName == "n32", "mabi=n32", Flags);
+  addMultilibFlag(ABIName == "n64", "mabi=n64", Flags);
+  addMultilibFlag(isSoftFloatABI(Args), "msoft-float", Flags);
+  addMultilibFlag(!isSoftFloatABI(Args), "mhard-float", Flags);
+  addMultilibFlag(isMipsEL(TargetArch), "EL", Flags);
+  addMultilibFlag(!isMipsEL(TargetArch), "EB", Flags);
+
+  if (TargetTriple.isAndroid())
+    return findMipsAndroidMultilibs(D.getVFS(), Path, Flags, NonExistent,
+                                    Result);
+
+  if (TargetTriple.getVendor() == llvm::Triple::MipsTechnologies &&
+      TargetTriple.getOS() == llvm::Triple::Linux &&
+      TargetTriple.getEnvironment() == llvm::Triple::UnknownEnvironment)
+    return findMipsMuslMultilibs(Flags, NonExistent, Result);
+
+  if (TargetTriple.getVendor() == llvm::Triple::MipsTechnologies &&
+      TargetTriple.getOS() == llvm::Triple::Linux &&
+      TargetTriple.isGNUEnvironment())
+    return findMipsMtiMultilibs(Flags, NonExistent, Result);
+
+  if (TargetTriple.getVendor() == llvm::Triple::ImaginationTechnologies &&
+      TargetTriple.getOS() == llvm::Triple::Linux &&
+      TargetTriple.isGNUEnvironment())
+    return findMipsImgMultilibs(Flags, NonExistent, Result);
+
+  if (findMipsCsMultilibs(Flags, NonExistent, Result))
+    return true;
+
+  // Fallback to the regular toolchain-tree structure.
+  Multilib Default;
+  Result.Multilibs.push_back(Default);
+  Result.Multilibs.FilterOut(NonExistent);
+
+  if (Result.Multilibs.select(Flags, Result.SelectedMultilib)) {
+    Result.BiarchSibling = Multilib();
+    return true;
+  }
+
+  return false;
+}
+
+static void findAndroidArmMultilibs(const Driver &D,
+                                    const llvm::Triple &TargetTriple,
+                                    StringRef Path, const ArgList &Args,
+                                    DetectedMultilibs &Result) {
+  // Find multilibs with subdirectories like armv7-a, thumb, armv7-a/thumb.
+  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
+  Multilib ArmV7Multilib = makeMultilib("/armv7-a")
+                               .flag("+march=armv7-a")
+                               .flag("-mthumb");
+  Multilib ThumbMultilib = makeMultilib("/thumb")
+                               .flag("-march=armv7-a")
+                               .flag("+mthumb");
+  Multilib ArmV7ThumbMultilib = makeMultilib("/armv7-a/thumb")
+                               .flag("+march=armv7-a")
+                               .flag("+mthumb");
+  Multilib DefaultMultilib = makeMultilib("")
+                               .flag("-march=armv7-a")
+                               .flag("-mthumb");
+  MultilibSet AndroidArmMultilibs =
+      MultilibSet()
+          .Either(ThumbMultilib, ArmV7Multilib,
+                  ArmV7ThumbMultilib, DefaultMultilib)
+          .FilterOut(NonExistent);
+
+  Multilib::flags_list Flags;
+  llvm::StringRef Arch = Args.getLastArgValue(options::OPT_march_EQ);
+  bool IsArmArch = TargetTriple.getArch() == llvm::Triple::arm;
+  bool IsThumbArch = TargetTriple.getArch() == llvm::Triple::thumb;
+  bool IsV7SubArch = TargetTriple.getSubArch() == llvm::Triple::ARMSubArch_v7;
+  bool IsThumbMode = IsThumbArch ||
+      Args.hasFlag(options::OPT_mthumb, options::OPT_mno_thumb, false) ||
+      (IsArmArch && llvm::ARM::parseArchISA(Arch) == llvm::ARM::ISAKind::THUMB);
+  bool IsArmV7Mode = (IsArmArch || IsThumbArch) &&
+      (llvm::ARM::parseArchVersion(Arch) == 7 ||
+       (IsArmArch && Arch == "" && IsV7SubArch));
+  addMultilibFlag(IsArmV7Mode, "march=armv7-a", Flags);
+  addMultilibFlag(IsThumbMode, "mthumb", Flags);
+
+  if (AndroidArmMultilibs.select(Flags, Result.SelectedMultilib))
+    Result.Multilibs = AndroidArmMultilibs;
+}
+
+static bool findMSP430Multilibs(const Driver &D,
+                                const llvm::Triple &TargetTriple,
+                                StringRef Path, const ArgList &Args,
+                                DetectedMultilibs &Result) {
+  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
+  Multilib MSP430Multilib = makeMultilib("/430");
+  // FIXME: when clang starts to support msp430x ISA additional logic
+  // to select between multilib must be implemented
+  // Multilib MSP430xMultilib = makeMultilib("/large");
+
+  Result.Multilibs.push_back(MSP430Multilib);
+  Result.Multilibs.FilterOut(NonExistent);
+
+  Multilib::flags_list Flags;
+  if (Result.Multilibs.select(Flags, Result.SelectedMultilib))
+    return true;
+
+  return false;
+}
+
+static void findRISCVBareMetalMultilibs(const Driver &D,
+                                        const llvm::Triple &TargetTriple,
+                                        StringRef Path, const ArgList &Args,
+                                        DetectedMultilibs &Result) {
+  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
+  struct RiscvMultilib {
+    StringRef march;
+    StringRef mabi;
+  };
+  // currently only support the set of multilibs like riscv-gnu-toolchain does.
+  // TODO: support MULTILIB_REUSE
+  SmallVector<RiscvMultilib, 8> RISCVMultilibSet = {
+      {"rv32i", "ilp32"},     {"rv32im", "ilp32"},     {"rv32iac", "ilp32"},
+      {"rv32imac", "ilp32"},  {"rv32imafc", "ilp32f"}, {"rv64imac", "lp64"},
+      {"rv64imafdc", "lp64d"}};
+
+  std::vector<Multilib> Ms;
+  for (auto Element : RISCVMultilibSet) {
+    // multilib path rule is ${march}/${mabi}
+    Ms.emplace_back(
+        makeMultilib((Twine(Element.march) + "/" + Twine(Element.mabi)).str())
+            .flag(Twine("+march=", Element.march).str())
+            .flag(Twine("+mabi=", Element.mabi).str()));
+  }
+  MultilibSet RISCVMultilibs =
+      MultilibSet()
+          .Either(ArrayRef<Multilib>(Ms))
+          .FilterOut(NonExistent)
+          .setFilePathsCallback([](const Multilib &M) {
+            return std::vector<std::string>(
+                {M.gccSuffix(),
+                 "/../../../../riscv64-unknown-elf/lib" + M.gccSuffix(),
+                 "/../../../../riscv32-unknown-elf/lib" + M.gccSuffix()});
+          });
+
+
+  Multilib::flags_list Flags;
+  llvm::StringSet<> Added_ABIs;
+  StringRef ABIName = tools::riscv::getRISCVABI(Args, TargetTriple);
+  StringRef MArch = tools::riscv::getRISCVArch(Args, TargetTriple);
+  for (auto Element : RISCVMultilibSet) {
+    addMultilibFlag(MArch == Element.march,
+                    Twine("march=", Element.march).str().c_str(), Flags);
+    if (!Added_ABIs.count(Element.mabi)) {
+      Added_ABIs.insert(Element.mabi);
+      addMultilibFlag(ABIName == Element.mabi,
+                      Twine("mabi=", Element.mabi).str().c_str(), Flags);
+    }
+  }
+
+  if (RISCVMultilibs.select(Flags, Result.SelectedMultilib))
+    Result.Multilibs = RISCVMultilibs;
+}
+
+static void findRISCVMultilibs(const Driver &D,
+                               const llvm::Triple &TargetTriple, StringRef Path,
+                               const ArgList &Args, DetectedMultilibs &Result) {
+  if (TargetTriple.getOS() == llvm::Triple::UnknownOS)
+    return findRISCVBareMetalMultilibs(D, TargetTriple, Path, Args, Result);
+
+  FilterNonExistent NonExistent(Path, "/crtbegin.o", D.getVFS());
+  Multilib Ilp32 = makeMultilib("lib32/ilp32").flag("+m32").flag("+mabi=ilp32");
+  Multilib Ilp32f =
+      makeMultilib("lib32/ilp32f").flag("+m32").flag("+mabi=ilp32f");
+  Multilib Ilp32d =
+      makeMultilib("lib32/ilp32d").flag("+m32").flag("+mabi=ilp32d");
+  Multilib Lp64 = makeMultilib("lib64/lp64").flag("+m64").flag("+mabi=lp64");
+  Multilib Lp64f = makeMultilib("lib64/lp64f").flag("+m64").flag("+mabi=lp64f");
+  Multilib Lp64d = makeMultilib("lib64/lp64d").flag("+m64").flag("+mabi=lp64d");
+  MultilibSet RISCVMultilibs =
+      MultilibSet()
+          .Either({Ilp32, Ilp32f, Ilp32d, Lp64, Lp64f, Lp64d})
+          .FilterOut(NonExistent);
+
+  Multilib::flags_list Flags;
+  bool IsRV64 = TargetTriple.getArch() == llvm::Triple::riscv64;
+  StringRef ABIName = tools::riscv::getRISCVABI(Args, TargetTriple);
+
+  addMultilibFlag(!IsRV64, "m32", Flags);
+  addMultilibFlag(IsRV64, "m64", Flags);
+  addMultilibFlag(ABIName == "ilp32", "mabi=ilp32", Flags);
+  addMultilibFlag(ABIName == "ilp32f", "mabi=ilp32f", Flags);
+  addMultilibFlag(ABIName == "ilp32d", "mabi=ilp32d", Flags);
+  addMultilibFlag(ABIName == "lp64", "mabi=lp64", Flags);
+  addMultilibFlag(ABIName == "lp64f", "mabi=lp64f", Flags);
+  addMultilibFlag(ABIName == "lp64d", "mabi=lp64d", Flags);
+
+  if (RISCVMultilibs.select(Flags, Result.SelectedMultilib))
+    Result.Multilibs = RISCVMultilibs;
+}
+
+static bool findBiarchMultilibs(const Driver &D,
+                                const llvm::Triple &TargetTriple,
+                                StringRef Path, const ArgList &Args,
+                                bool NeedsBiarchSuffix,
+                                DetectedMultilibs &Result) {
+  Multilib Default;
+
+  // Some versions of SUSE and Fedora on ppc64 put 32-bit libs
+  // in what would normally be GCCInstallPath and put the 64-bit
+  // libs in a subdirectory named 64. The simple logic we follow is that
+  // *if* there is a subdirectory of the right name with crtbegin.o in it,
+  // we use that. If not, and if not a biarch triple alias, we look for
+  // crtbegin.o without the subdirectory.
+
+  StringRef Suff64 = "/64";
+  // Solaris uses platform-specific suffixes instead of /64.
+  if (TargetTriple.getOS() == llvm::Triple::Solaris) {
+    switch (TargetTriple.getArch()) {
+    case llvm::Triple::x86:
+    case llvm::Triple::x86_64:
+      Suff64 = "/amd64";
+      break;
+    case llvm::Triple::sparc:
+    case llvm::Triple::sparcv9:
+      Suff64 = "/sparcv9";
+      break;
+    default:
+      break;
+    }
+  }
+
+  Multilib Alt64 = Multilib()
+                       .gccSuffix(Suff64)
+                       .includeSuffix(Suff64)
+                       .flag("-m32")
+                       .flag("+m64")
+                       .flag("-mx32");
+  Multilib Alt32 = Multilib()
+                       .gccSuffix("/32")
+                       .includeSuffix("/32")
+                       .flag("+m32")
+                       .flag("-m64")
+                       .flag("-mx32");
+  Multilib Altx32 = Multilib()
+                        .gccSuffix("/x32")
+                        .includeSuffix("/x32")
+                        .flag("-m32")
+                        .flag("-m64")
+                        .flag("+mx32");
+
+  // GCC toolchain for IAMCU doesn't have crtbegin.o, so look for libgcc.a.
+  FilterNonExistent NonExistent(
+      Path, TargetTriple.isOSIAMCU() ? "/libgcc.a" : "/crtbegin.o", D.getVFS());
+
+  // Determine default multilib from: 32, 64, x32
+  // Also handle cases such as 64 on 32, 32 on 64, etc.
+  enum { UNKNOWN, WANT32, WANT64, WANTX32 } Want = UNKNOWN;
+  const bool IsX32 = TargetTriple.getEnvironment() == llvm::Triple::GNUX32;
+  if (TargetTriple.isArch32Bit() && !NonExistent(Alt32))
+    Want = WANT64;
+  else if (TargetTriple.isArch64Bit() && IsX32 && !NonExistent(Altx32))
+    Want = WANT64;
+  else if (TargetTriple.isArch64Bit() && !IsX32 && !NonExistent(Alt64))
+    Want = WANT32;
+  else {
+    if (TargetTriple.isArch32Bit())
+      Want = NeedsBiarchSuffix ? WANT64 : WANT32;
+    else if (IsX32)
+      Want = NeedsBiarchSuffix ? WANT64 : WANTX32;
+    else
+      Want = NeedsBiarchSuffix ? WANT32 : WANT64;
+  }
+
+  if (Want == WANT32)
+    Default.flag("+m32").flag("-m64").flag("-mx32");
+  else if (Want == WANT64)
+    Default.flag("-m32").flag("+m64").flag("-mx32");
+  else if (Want == WANTX32)
+    Default.flag("-m32").flag("-m64").flag("+mx32");
+  else
+    return false;
+
+  Result.Multilibs.push_back(Default);
+  Result.Multilibs.push_back(Alt64);
+  Result.Multilibs.push_back(Alt32);
+  Result.Multilibs.push_back(Altx32);
+
+  Result.Multilibs.FilterOut(NonExistent);
+
+  Multilib::flags_list Flags;
+  addMultilibFlag(TargetTriple.isArch64Bit() && !IsX32, "m64", Flags);
+  addMultilibFlag(TargetTriple.isArch32Bit(), "m32", Flags);
+  addMultilibFlag(TargetTriple.isArch64Bit() && IsX32, "mx32", Flags);
+
+  if (!Result.Multilibs.select(Flags, Result.SelectedMultilib))
+    return false;
+
+  if (Result.SelectedMultilib == Alt64 || Result.SelectedMultilib == Alt32 ||
+      Result.SelectedMultilib == Altx32)
+    Result.BiarchSibling = Default;
+
+  return true;
+}
+
+/// Generic_GCC - A tool chain using the 'gcc' command to perform
+/// all subcommands; this relies on gcc translating the majority of
+/// command line options.
+
+/// Less-than for GCCVersion, implementing a Strict Weak Ordering.
+bool Generic_GCC::GCCVersion::isOlderThan(int RHSMajor, int RHSMinor,
+                                          int RHSPatch,
+                                          StringRef RHSPatchSuffix) const {
+  if (Major != RHSMajor)
+    return Major < RHSMajor;
+  if (Minor != RHSMinor)
+    return Minor < RHSMinor;
+  if (Patch != RHSPatch) {
+    // Note that versions without a specified patch sort higher than those with
+    // a patch.
+    if (RHSPatch == -1)
+      return true;
+    if (Patch == -1)
+      return false;
+
+    // Otherwise just sort on the patch itself.
+    return Patch < RHSPatch;
+  }
+  if (PatchSuffix != RHSPatchSuffix) {
+    // Sort empty suffixes higher.
+    if (RHSPatchSuffix.empty())
+      return true;
+    if (PatchSuffix.empty())
+      return false;
+
+    // Provide a lexicographic sort to make this a total ordering.
+    return PatchSuffix < RHSPatchSuffix;
+  }
+
+  // The versions are equal.
+  return false;
+}
+
+/// Parse a GCCVersion object out of a string of text.
+///
+/// This is the primary means of forming GCCVersion objects.
+/*static*/
+Generic_GCC::GCCVersion Generic_GCC::GCCVersion::Parse(StringRef VersionText) {
+  const GCCVersion BadVersion = {VersionText.str(), -1, -1, -1, "", "", ""};
+  std::pair<StringRef, StringRef> First = VersionText.split('.');
+  std::pair<StringRef, StringRef> Second = First.second.split('.');
+
+  GCCVersion GoodVersion = {VersionText.str(), -1, -1, -1, "", "", ""};
+  if (First.first.getAsInteger(10, GoodVersion.Major) || GoodVersion.Major < 0)
+    return BadVersion;
+  GoodVersion.MajorStr = First.first.str();
+  if (First.second.empty())
+    return GoodVersion;
+  StringRef MinorStr = Second.first;
+  if (Second.second.empty()) {
+    if (size_t EndNumber = MinorStr.find_first_not_of("0123456789")) {
+      GoodVersion.PatchSuffix = MinorStr.substr(EndNumber);
+      MinorStr = MinorStr.slice(0, EndNumber);
+    }
+  }
+  if (MinorStr.getAsInteger(10, GoodVersion.Minor) || GoodVersion.Minor < 0)
+    return BadVersion;
+  GoodVersion.MinorStr = MinorStr.str();
+
+  // First look for a number prefix and parse that if present. Otherwise just
+  // stash the entire patch string in the suffix, and leave the number
+  // unspecified. This covers versions strings such as:
+  //   5        (handled above)
+  //   4.4
+  //   4.4-patched
+  //   4.4.0
+  //   4.4.x
+  //   4.4.2-rc4
+  //   4.4.x-patched
+  // And retains any patch number it finds.
+  StringRef PatchText = Second.second;
+  if (!PatchText.empty()) {
+    if (size_t EndNumber = PatchText.find_first_not_of("0123456789")) {
+      // Try to parse the number and any suffix.
+      if (PatchText.slice(0, EndNumber).getAsInteger(10, GoodVersion.Patch) ||
+          GoodVersion.Patch < 0)
+        return BadVersion;
+      GoodVersion.PatchSuffix = PatchText.substr(EndNumber);
+    }
+  }
+
+  return GoodVersion;
+}
+
+static llvm::StringRef getGCCToolchainDir(const ArgList &Args,
+                                          llvm::StringRef SysRoot) {
+  const Arg *A = Args.getLastArg(clang::driver::options::OPT_gcc_toolchain);
+  if (A)
+    return A->getValue();
+
+  // If we have a SysRoot, ignore GCC_INSTALL_PREFIX.
+  // GCC_INSTALL_PREFIX specifies the gcc installation for the default
+  // sysroot and is likely not valid with a different sysroot.
+  if (!SysRoot.empty())
+    return "";
+
+  return GCC_INSTALL_PREFIX;
+}
+
+/// Initialize a GCCInstallationDetector from the driver.
+///
+/// This performs all of the autodetection and sets up the various paths.
+/// Once constructed, a GCCInstallationDetector is essentially immutable.
+///
+/// FIXME: We shouldn't need an explicit TargetTriple parameter here, and
+/// should instead pull the target out of the driver. This is currently
+/// necessary because the driver doesn't store the final version of the target
+/// triple.
+void Generic_GCC::GCCInstallationDetector::init(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    ArrayRef<std::string> ExtraTripleAliases) {
+  llvm::Triple BiarchVariantTriple = TargetTriple.isArch32Bit()
+                                         ? TargetTriple.get64BitArchVariant()
+                                         : TargetTriple.get32BitArchVariant();
+  // The library directories which may contain GCC installations.
+  SmallVector<StringRef, 4> CandidateLibDirs, CandidateBiarchLibDirs;
+  // The compatible GCC triples for this particular architecture.
+  SmallVector<StringRef, 16> CandidateTripleAliases;
+  SmallVector<StringRef, 16> CandidateBiarchTripleAliases;
+  CollectLibDirsAndTriples(TargetTriple, BiarchVariantTriple, CandidateLibDirs,
+                           CandidateTripleAliases, CandidateBiarchLibDirs,
+                           CandidateBiarchTripleAliases);
+
+  // Compute the set of prefixes for our search.
+  SmallVector<std::string, 8> Prefixes(D.PrefixDirs.begin(),
+                                       D.PrefixDirs.end());
+
+  StringRef GCCToolchainDir = getGCCToolchainDir(Args, D.SysRoot);
+  if (GCCToolchainDir != "") {
+    if (GCCToolchainDir.back() == '/')
+      GCCToolchainDir = GCCToolchainDir.drop_back(); // remove the /
+
+    Prefixes.push_back(GCCToolchainDir);
+  } else {
+    // If we have a SysRoot, try that first.
+    if (!D.SysRoot.empty()) {
+      Prefixes.push_back(D.SysRoot);
+      AddDefaultGCCPrefixes(TargetTriple, Prefixes, D.SysRoot);
+    }
+
+    // Then look for gcc installed alongside clang.
+    Prefixes.push_back(D.InstalledDir + "/..");
+
+    // Next, look for prefix(es) that correspond to distribution-supplied gcc
+    // installations.
+    if (D.SysRoot.empty()) {
+      // Typically /usr.
+      AddDefaultGCCPrefixes(TargetTriple, Prefixes, D.SysRoot);
+    }
+  }
+
+  // Try to respect gcc-config on Gentoo. However, do that only
+  // if --gcc-toolchain is not provided or equal to the Gentoo install
+  // in /usr. This avoids accidentally enforcing the system GCC version
+  // when using a custom toolchain.
+  if (GCCToolchainDir == "" || GCCToolchainDir == D.SysRoot + "/usr") {
+    SmallVector<StringRef, 16> GentooTestTriples;
+    // Try to match an exact triple as target triple first.
+    // e.g. crossdev -S x86_64-gentoo-linux-gnu will install gcc libs for
+    // x86_64-gentoo-linux-gnu. But "clang -target x86_64-gentoo-linux-gnu"
+    // may pick the libraries for x86_64-pc-linux-gnu even when exact matching
+    // triple x86_64-gentoo-linux-gnu is present.
+    GentooTestTriples.push_back(TargetTriple.str());
+    // Check rest of triples.
+    GentooTestTriples.append(ExtraTripleAliases.begin(),
+                             ExtraTripleAliases.end());
+    GentooTestTriples.append(CandidateTripleAliases.begin(),
+                             CandidateTripleAliases.end());
+    if (ScanGentooConfigs(TargetTriple, Args, GentooTestTriples,
+                          CandidateBiarchTripleAliases))
+      return;
+  }
+
+  // Loop over the various components which exist and select the best GCC
+  // installation available. GCC installs are ranked by version number.
+  Version = GCCVersion::Parse("0.0.0");
+  for (const std::string &Prefix : Prefixes) {
+    if (!D.getVFS().exists(Prefix))
+      continue;
+    for (StringRef Suffix : CandidateLibDirs) {
+      const std::string LibDir = Prefix + Suffix.str();
+      if (!D.getVFS().exists(LibDir))
+        continue;
+      // Try to match the exact target triple first.
+      ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, TargetTriple.str());
+      // Try rest of possible triples.
+      for (StringRef Candidate : ExtraTripleAliases) // Try these first.
+        ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, Candidate);
+      for (StringRef Candidate : CandidateTripleAliases)
+        ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, Candidate);
+    }
+    for (StringRef Suffix : CandidateBiarchLibDirs) {
+      const std::string LibDir = Prefix + Suffix.str();
+      if (!D.getVFS().exists(LibDir))
+        continue;
+      for (StringRef Candidate : CandidateBiarchTripleAliases)
+        ScanLibDirForGCCTriple(TargetTriple, Args, LibDir, Candidate,
+                               /*NeedsBiarchSuffix=*/ true);
+    }
+  }
+}
+
+void Generic_GCC::GCCInstallationDetector::print(raw_ostream &OS) const {
+  for (const auto &InstallPath : CandidateGCCInstallPaths)
+    OS << "Found candidate GCC installation: " << InstallPath << "\n";
+
+  if (!GCCInstallPath.empty())
+    OS << "Selected GCC installation: " << GCCInstallPath << "\n";
+
+  for (const auto &Multilib : Multilibs)
+    OS << "Candidate multilib: " << Multilib << "\n";
+
+  if (Multilibs.size() != 0 || !SelectedMultilib.isDefault())
+    OS << "Selected multilib: " << SelectedMultilib << "\n";
+}
+
+bool Generic_GCC::GCCInstallationDetector::getBiarchSibling(Multilib &M) const {
+  if (BiarchSibling.hasValue()) {
+    M = BiarchSibling.getValue();
+    return true;
+  }
+  return false;
+}
+
+void Generic_GCC::GCCInstallationDetector::AddDefaultGCCPrefixes(
+    const llvm::Triple &TargetTriple, SmallVectorImpl<std::string> &Prefixes,
+    StringRef SysRoot) {
+  if (TargetTriple.getOS() == llvm::Triple::Solaris) {
+    // Solaris is a special case.
+    // The GCC installation is under
+    //   /usr/gcc/<major>.<minor>/lib/gcc/<triple>/<major>.<minor>.<patch>/
+    // so we need to find those /usr/gcc/*/lib/gcc libdirs and go with
+    // /usr/gcc/<version> as a prefix.
+
+    std::string PrefixDir = SysRoot.str() + "/usr/gcc";
+    std::error_code EC;
+    for (llvm::vfs::directory_iterator LI = D.getVFS().dir_begin(PrefixDir, EC),
+                                       LE;
+         !EC && LI != LE; LI = LI.increment(EC)) {
+      StringRef VersionText = llvm::sys::path::filename(LI->path());
+      GCCVersion CandidateVersion = GCCVersion::Parse(VersionText);
+
+      // Filter out obviously bad entries.
+      if (CandidateVersion.Major == -1 || CandidateVersion.isOlderThan(4, 1, 1))
+        continue;
+
+      std::string CandidatePrefix = PrefixDir + "/" + VersionText.str();
+      std::string CandidateLibPath = CandidatePrefix + "/lib/gcc";
+      if (!D.getVFS().exists(CandidateLibPath))
+        continue;
+
+      Prefixes.push_back(CandidatePrefix);
+    }
+    return;
+  }
+
+  // Non-Solaris is much simpler - most systems just go with "/usr".
+  if (SysRoot.empty() && TargetTriple.getOS() == llvm::Triple::Linux) {
+    // Yet, still look for RHEL devtoolsets.
+    Prefixes.push_back("/opt/rh/devtoolset-8/root/usr");
+    Prefixes.push_back("/opt/rh/devtoolset-7/root/usr");
+    Prefixes.push_back("/opt/rh/devtoolset-6/root/usr");
+    Prefixes.push_back("/opt/rh/devtoolset-4/root/usr");
+    Prefixes.push_back("/opt/rh/devtoolset-3/root/usr");
+    Prefixes.push_back("/opt/rh/devtoolset-2/root/usr");
+  }
+  Prefixes.push_back(SysRoot.str() + "/usr");
+}
+
+/*static*/ void Generic_GCC::GCCInstallationDetector::CollectLibDirsAndTriples(
+    const llvm::Triple &TargetTriple, const llvm::Triple &BiarchTriple,
+    SmallVectorImpl<StringRef> &LibDirs,
+    SmallVectorImpl<StringRef> &TripleAliases,
+    SmallVectorImpl<StringRef> &BiarchLibDirs,
+    SmallVectorImpl<StringRef> &BiarchTripleAliases) {
+  // Declare a bunch of static data sets that we'll select between below. These
+  // are specifically designed to always refer to string literals to avoid any
+  // lifetime or initialization issues.
+  static const char *const AArch64LibDirs[] = {"/lib64", "/lib"};
+  static const char *const AArch64Triples[] = {
+      "aarch64-none-linux-gnu", "aarch64-linux-gnu", "aarch64-redhat-linux",
+      "aarch64-suse-linux", "aarch64-linux-android"};
+  static const char *const AArch64beLibDirs[] = {"/lib"};
+  static const char *const AArch64beTriples[] = {"aarch64_be-none-linux-gnu",
+                                                 "aarch64_be-linux-gnu"};
+
+  static const char *const ARMLibDirs[] = {"/lib"};
+  static const char *const ARMTriples[] = {"arm-linux-gnueabi",
+                                           "arm-linux-androideabi"};
+  static const char *const ARMHFTriples[] = {"arm-linux-gnueabihf",
+                                             "armv7hl-redhat-linux-gnueabi",
+                                             "armv6hl-suse-linux-gnueabi",
+                                             "armv7hl-suse-linux-gnueabi"};
+  static const char *const ARMebLibDirs[] = {"/lib"};
+  static const char *const ARMebTriples[] = {"armeb-linux-gnueabi",
+                                             "armeb-linux-androideabi"};
+  static const char *const ARMebHFTriples[] = {
+      "armeb-linux-gnueabihf", "armebv7hl-redhat-linux-gnueabi"};
+
+  static const char *const AVRLibDirs[] = {"/lib"};
+  static const char *const AVRTriples[] = {"avr"};
+
+  static const char *const X86_64LibDirs[] = {"/lib64", "/lib"};
+  static const char *const X86_64Triples[] = {
+      "x86_64-linux-gnu",       "x86_64-unknown-linux-gnu",
+      "x86_64-pc-linux-gnu",    "x86_64-redhat-linux6E",
+      "x86_64-redhat-linux",    "x86_64-suse-linux",
+      "x86_64-manbo-linux-gnu", "x86_64-linux-gnu",
+      "x86_64-slackware-linux", "x86_64-unknown-linux",
+      "x86_64-amazon-linux",    "x86_64-linux-android"};
+  static const char *const X32LibDirs[] = {"/libx32"};
+  static const char *const X86LibDirs[] = {"/lib32", "/lib"};
+  static const char *const X86Triples[] = {
+      "i686-linux-gnu",       "i686-pc-linux-gnu",     "i486-linux-gnu",
+      "i386-linux-gnu",       "i386-redhat-linux6E",   "i686-redhat-linux",
+      "i586-redhat-linux",    "i386-redhat-linux",     "i586-suse-linux",
+      "i486-slackware-linux", "i686-montavista-linux", "i586-linux-gnu",
+      "i686-linux-android",   "i386-gnu",              "i486-gnu",
+      "i586-gnu",             "i686-gnu"};
+
+  static const char *const MIPSLibDirs[] = {"/lib"};
+  static const char *const MIPSTriples[] = {
+      "mips-linux-gnu", "mips-mti-linux", "mips-mti-linux-gnu",
+      "mips-img-linux-gnu", "mipsisa32r6-linux-gnu"};
+  static const char *const MIPSELLibDirs[] = {"/lib"};
+  static const char *const MIPSELTriples[] = {
+      "mipsel-linux-gnu", "mips-img-linux-gnu", "mipsisa32r6el-linux-gnu",
+      "mipsel-linux-android"};
+
+  static const char *const MIPS64LibDirs[] = {"/lib64", "/lib"};
+  static const char *const MIPS64Triples[] = {
+      "mips64-linux-gnu",      "mips-mti-linux-gnu",
+      "mips-img-linux-gnu",    "mips64-linux-gnuabi64",
+      "mipsisa64r6-linux-gnu", "mipsisa64r6-linux-gnuabi64"};
+  static const char *const MIPS64ELLibDirs[] = {"/lib64", "/lib"};
+  static const char *const MIPS64ELTriples[] = {
+      "mips64el-linux-gnu",      "mips-mti-linux-gnu",
+      "mips-img-linux-gnu",      "mips64el-linux-gnuabi64",
+      "mipsisa64r6el-linux-gnu", "mipsisa64r6el-linux-gnuabi64",
+      "mips64el-linux-android"};
+
+  static const char *const MIPSN32LibDirs[] = {"/lib32"};
+  static const char *const MIPSN32Triples[] = {"mips64-linux-gnuabin32",
+                                               "mipsisa64r6-linux-gnuabin32"};
+  static const char *const MIPSN32ELLibDirs[] = {"/lib32"};
+  static const char *const MIPSN32ELTriples[] = {
+      "mips64el-linux-gnuabin32", "mipsisa64r6el-linux-gnuabin32"};
+
+  static const char *const MSP430LibDirs[] = {"/lib"};
+  static const char *const MSP430Triples[] = {"msp430-elf"};
+
+  static const char *const PPCLibDirs[] = {"/lib32", "/lib"};
+  static const char *const PPCTriples[] = {
+      "powerpc-linux-gnu", "powerpc-unknown-linux-gnu", "powerpc-linux-gnuspe",
+      // On 32-bit PowerPC systems running SUSE Linux, gcc is configured as a
+      // 64-bit compiler which defaults to "-m32", hence "powerpc64-suse-linux".
+      "powerpc64-suse-linux", "powerpc-montavista-linuxspe"};
+  static const char *const PPC64LibDirs[] = {"/lib64", "/lib"};
+  static const char *const PPC64Triples[] = {
+      "powerpc64-linux-gnu", "powerpc64-unknown-linux-gnu",
+      "powerpc64-suse-linux", "ppc64-redhat-linux"};
+  static const char *const PPC64LELibDirs[] = {"/lib64", "/lib"};
+  static const char *const PPC64LETriples[] = {
+      "powerpc64le-linux-gnu", "powerpc64le-unknown-linux-gnu",
+      "powerpc64le-suse-linux", "ppc64le-redhat-linux"};
+
+  static const char *const RISCV32LibDirs[] = {"/lib32", "/lib"};
+  static const char *const RISCV32Triples[] = {"riscv32-unknown-linux-gnu",
+                                               "riscv32-linux-gnu",
+                                               "riscv32-unknown-elf"};
+  static const char *const RISCV64LibDirs[] = {"/lib64", "/lib"};
+  static const char *const RISCV64Triples[] = {"riscv64-unknown-linux-gnu",
+                                               "riscv64-linux-gnu",
+                                               "riscv64-unknown-elf",
+                                               "riscv64-suse-linux"};
+
+  static const char *const SPARCv8LibDirs[] = {"/lib32", "/lib"};
+  static const char *const SPARCv8Triples[] = {"sparc-linux-gnu",
+                                               "sparcv8-linux-gnu"};
+  static const char *const SPARCv9LibDirs[] = {"/lib64", "/lib"};
+  static const char *const SPARCv9Triples[] = {"sparc64-linux-gnu",
+                                               "sparcv9-linux-gnu"};
+
+  static const char *const SystemZLibDirs[] = {"/lib64", "/lib"};
+  static const char *const SystemZTriples[] = {
+      "s390x-linux-gnu", "s390x-unknown-linux-gnu", "s390x-ibm-linux-gnu",
+      "s390x-suse-linux", "s390x-redhat-linux"};
+
+
+  using std::begin;
+  using std::end;
+
+  if (TargetTriple.getOS() == llvm::Triple::Solaris) {
+    static const char *const SolarisLibDirs[] = {"/lib"};
+    static const char *const SolarisSparcV8Triples[] = {
+        "sparc-sun-solaris2.11", "sparc-sun-solaris2.12"};
+    static const char *const SolarisSparcV9Triples[] = {
+        "sparcv9-sun-solaris2.11", "sparcv9-sun-solaris2.12"};
+    static const char *const SolarisX86Triples[] = {"i386-pc-solaris2.11",
+                                                    "i386-pc-solaris2.12"};
+    static const char *const SolarisX86_64Triples[] = {"x86_64-pc-solaris2.11",
+                                                       "x86_64-pc-solaris2.12"};
+    LibDirs.append(begin(SolarisLibDirs), end(SolarisLibDirs));
+    BiarchLibDirs.append(begin(SolarisLibDirs), end(SolarisLibDirs));
+    switch (TargetTriple.getArch()) {
+    case llvm::Triple::x86:
+      TripleAliases.append(begin(SolarisX86Triples), end(SolarisX86Triples));
+      BiarchTripleAliases.append(begin(SolarisX86_64Triples),
+                                 end(SolarisX86_64Triples));
+      break;
+    case llvm::Triple::x86_64:
+      TripleAliases.append(begin(SolarisX86_64Triples),
+                           end(SolarisX86_64Triples));
+      BiarchTripleAliases.append(begin(SolarisX86Triples),
+                                 end(SolarisX86Triples));
+      break;
+    case llvm::Triple::sparc:
+      TripleAliases.append(begin(SolarisSparcV8Triples),
+                           end(SolarisSparcV8Triples));
+      BiarchTripleAliases.append(begin(SolarisSparcV9Triples),
+                                 end(SolarisSparcV9Triples));
+      break;
+    case llvm::Triple::sparcv9:
+      TripleAliases.append(begin(SolarisSparcV9Triples),
+                           end(SolarisSparcV9Triples));
+      BiarchTripleAliases.append(begin(SolarisSparcV8Triples),
+                                 end(SolarisSparcV8Triples));
+      break;
+    default:
+      break;
+    }
+    return;
+  }
+
+  // Android targets should not use GNU/Linux tools or libraries.
+  if (TargetTriple.isAndroid()) {
+    static const char *const AArch64AndroidTriples[] = {
+        "aarch64-linux-android"};
+    static const char *const ARMAndroidTriples[] = {"arm-linux-androideabi"};
+    static const char *const MIPSELAndroidTriples[] = {"mipsel-linux-android"};
+    static const char *const MIPS64ELAndroidTriples[] = {
+        "mips64el-linux-android"};
+    static const char *const X86AndroidTriples[] = {"i686-linux-android"};
+    static const char *const X86_64AndroidTriples[] = {"x86_64-linux-android"};
+
+    switch (TargetTriple.getArch()) {
+    case llvm::Triple::aarch64:
+      LibDirs.append(begin(AArch64LibDirs), end(AArch64LibDirs));
+      TripleAliases.append(begin(AArch64AndroidTriples),
+                           end(AArch64AndroidTriples));
+      break;
+    case llvm::Triple::arm:
+    case llvm::Triple::thumb:
+      LibDirs.append(begin(ARMLibDirs), end(ARMLibDirs));
+      TripleAliases.append(begin(ARMAndroidTriples), end(ARMAndroidTriples));
+      break;
+    case llvm::Triple::mipsel:
+      LibDirs.append(begin(MIPSELLibDirs), end(MIPSELLibDirs));
+      TripleAliases.append(begin(MIPSELAndroidTriples),
+                           end(MIPSELAndroidTriples));
+      BiarchLibDirs.append(begin(MIPS64ELLibDirs), end(MIPS64ELLibDirs));
+      BiarchTripleAliases.append(begin(MIPS64ELAndroidTriples),
+                                 end(MIPS64ELAndroidTriples));
+      break;
+    case llvm::Triple::mips64el:
+      LibDirs.append(begin(MIPS64ELLibDirs), end(MIPS64ELLibDirs));
+      TripleAliases.append(begin(MIPS64ELAndroidTriples),
+                           end(MIPS64ELAndroidTriples));
+      BiarchLibDirs.append(begin(MIPSELLibDirs), end(MIPSELLibDirs));
+      BiarchTripleAliases.append(begin(MIPSELAndroidTriples),
+                                 end(MIPSELAndroidTriples));
+      break;
+    case llvm::Triple::x86_64:
+      LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+      TripleAliases.append(begin(X86_64AndroidTriples),
+                           end(X86_64AndroidTriples));
+      BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
+      BiarchTripleAliases.append(begin(X86AndroidTriples),
+                                 end(X86AndroidTriples));
+      break;
+    case llvm::Triple::x86:
+      LibDirs.append(begin(X86LibDirs), end(X86LibDirs));
+      TripleAliases.append(begin(X86AndroidTriples), end(X86AndroidTriples));
+      BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+      BiarchTripleAliases.append(begin(X86_64AndroidTriples),
+                                 end(X86_64AndroidTriples));
+      break;
+    default:
+      break;
+    }
+
+    return;
+  }
+
+  switch (TargetTriple.getArch()) {
+  case llvm::Triple::aarch64:
+    LibDirs.append(begin(AArch64LibDirs), end(AArch64LibDirs));
+    TripleAliases.append(begin(AArch64Triples), end(AArch64Triples));
+    BiarchLibDirs.append(begin(AArch64LibDirs), end(AArch64LibDirs));
+    BiarchTripleAliases.append(begin(AArch64Triples), end(AArch64Triples));
+    break;
+  case llvm::Triple::aarch64_be:
+    LibDirs.append(begin(AArch64beLibDirs), end(AArch64beLibDirs));
+    TripleAliases.append(begin(AArch64beTriples), end(AArch64beTriples));
+    BiarchLibDirs.append(begin(AArch64beLibDirs), end(AArch64beLibDirs));
+    BiarchTripleAliases.append(begin(AArch64beTriples), end(AArch64beTriples));
+    break;
+  case llvm::Triple::arm:
+  case llvm::Triple::thumb:
+    LibDirs.append(begin(ARMLibDirs), end(ARMLibDirs));
+    if (TargetTriple.getEnvironment() == llvm::Triple::GNUEABIHF) {
+      TripleAliases.append(begin(ARMHFTriples), end(ARMHFTriples));
+    } else {
+      TripleAliases.append(begin(ARMTriples), end(ARMTriples));
+    }
+    break;
+  case llvm::Triple::armeb:
+  case llvm::Triple::thumbeb:
+    LibDirs.append(begin(ARMebLibDirs), end(ARMebLibDirs));
+    if (TargetTriple.getEnvironment() == llvm::Triple::GNUEABIHF) {
+      TripleAliases.append(begin(ARMebHFTriples), end(ARMebHFTriples));
+    } else {
+      TripleAliases.append(begin(ARMebTriples), end(ARMebTriples));
+    }
+    break;
+  case llvm::Triple::avr:
+    LibDirs.append(begin(AVRLibDirs), end(AVRLibDirs));
+    TripleAliases.append(begin(AVRTriples), end(AVRTriples));
+    break;
+  case llvm::Triple::x86_64:
+    LibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+    TripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
+    // x32 is always available when x86_64 is available, so adding it as
+    // secondary arch with x86_64 triples
+    if (TargetTriple.getEnvironment() == llvm::Triple::GNUX32) {
+      BiarchLibDirs.append(begin(X32LibDirs), end(X32LibDirs));
+      BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
+    } else {
+      BiarchLibDirs.append(begin(X86LibDirs), end(X86LibDirs));
+      BiarchTripleAliases.append(begin(X86Triples), end(X86Triples));
+    }
+    break;
+  case llvm::Triple::x86:
+    LibDirs.append(begin(X86LibDirs), end(X86LibDirs));
+    // MCU toolchain is 32 bit only and its triple alias is TargetTriple
+    // itself, which will be appended below.
+    if (!TargetTriple.isOSIAMCU()) {
+      TripleAliases.append(begin(X86Triples), end(X86Triples));
+      BiarchLibDirs.append(begin(X86_64LibDirs), end(X86_64LibDirs));
+      BiarchTripleAliases.append(begin(X86_64Triples), end(X86_64Triples));
+    }
+    break;
+  case llvm::Triple::mips:
+    LibDirs.append(begin(MIPSLibDirs), end(MIPSLibDirs));
+    TripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
+    BiarchLibDirs.append(begin(MIPS64LibDirs), end(MIPS64LibDirs));
+    BiarchTripleAliases.append(begin(MIPS64Triples), end(MIPS64Triples));
+    BiarchLibDirs.append(begin(MIPSN32LibDirs), end(MIPSN32LibDirs));
+    BiarchTripleAliases.append(begin(MIPSN32Triples), end(MIPSN32Triples));
+    break;
+  case llvm::Triple::mipsel:
+    LibDirs.append(begin(MIPSELLibDirs), end(MIPSELLibDirs));
+    TripleAliases.append(begin(MIPSELTriples), end(MIPSELTriples));
+    TripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
+    BiarchLibDirs.append(begin(MIPS64ELLibDirs), end(MIPS64ELLibDirs));
+    BiarchTripleAliases.append(begin(MIPS64ELTriples), end(MIPS64ELTriples));
+    BiarchLibDirs.append(begin(MIPSN32ELLibDirs), end(MIPSN32ELLibDirs));
+    BiarchTripleAliases.append(begin(MIPSN32ELTriples), end(MIPSN32ELTriples));
+    break;
+  case llvm::Triple::mips64:
+    LibDirs.append(begin(MIPS64LibDirs), end(MIPS64LibDirs));
+    TripleAliases.append(begin(MIPS64Triples), end(MIPS64Triples));
+    BiarchLibDirs.append(begin(MIPSLibDirs), end(MIPSLibDirs));
+    BiarchTripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
+    BiarchLibDirs.append(begin(MIPSN32LibDirs), end(MIPSN32LibDirs));
+    BiarchTripleAliases.append(begin(MIPSN32Triples), end(MIPSN32Triples));
+    break;
+  case llvm::Triple::mips64el:
+    LibDirs.append(begin(MIPS64ELLibDirs), end(MIPS64ELLibDirs));
+    TripleAliases.append(begin(MIPS64ELTriples), end(MIPS64ELTriples));
+    BiarchLibDirs.append(begin(MIPSELLibDirs), end(MIPSELLibDirs));
+    BiarchTripleAliases.append(begin(MIPSELTriples), end(MIPSELTriples));
+    BiarchLibDirs.append(begin(MIPSN32ELLibDirs), end(MIPSN32ELLibDirs));
+    BiarchTripleAliases.append(begin(MIPSN32ELTriples), end(MIPSN32ELTriples));
+    BiarchTripleAliases.append(begin(MIPSTriples), end(MIPSTriples));
+    break;
+  case llvm::Triple::msp430:
+    LibDirs.append(begin(MSP430LibDirs), end(MSP430LibDirs));
+    TripleAliases.append(begin(MSP430Triples), end(MSP430Triples));
+    break;
+  case llvm::Triple::ppc:
+    LibDirs.append(begin(PPCLibDirs), end(PPCLibDirs));
+    TripleAliases.append(begin(PPCTriples), end(PPCTriples));
+    BiarchLibDirs.append(begin(PPC64LibDirs), end(PPC64LibDirs));
+    BiarchTripleAliases.append(begin(PPC64Triples), end(PPC64Triples));
+    break;
+  case llvm::Triple::ppc64:
+    LibDirs.append(begin(PPC64LibDirs), end(PPC64LibDirs));
+    TripleAliases.append(begin(PPC64Triples), end(PPC64Triples));
+    BiarchLibDirs.append(begin(PPCLibDirs), end(PPCLibDirs));
+    BiarchTripleAliases.append(begin(PPCTriples), end(PPCTriples));
+    break;
+  case llvm::Triple::ppc64le:
+    LibDirs.append(begin(PPC64LELibDirs), end(PPC64LELibDirs));
+    TripleAliases.append(begin(PPC64LETriples), end(PPC64LETriples));
+    break;
+  case llvm::Triple::riscv32:
+    LibDirs.append(begin(RISCV32LibDirs), end(RISCV32LibDirs));
+    TripleAliases.append(begin(RISCV32Triples), end(RISCV32Triples));
+    BiarchLibDirs.append(begin(RISCV64LibDirs), end(RISCV64LibDirs));
+    BiarchTripleAliases.append(begin(RISCV64Triples), end(RISCV64Triples));
+    break;
+  case llvm::Triple::riscv64:
+    LibDirs.append(begin(RISCV64LibDirs), end(RISCV64LibDirs));
+    TripleAliases.append(begin(RISCV64Triples), end(RISCV64Triples));
+    BiarchLibDirs.append(begin(RISCV32LibDirs), end(RISCV32LibDirs));
+    BiarchTripleAliases.append(begin(RISCV32Triples), end(RISCV32Triples));
+    break;
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel:
+    LibDirs.append(begin(SPARCv8LibDirs), end(SPARCv8LibDirs));
+    TripleAliases.append(begin(SPARCv8Triples), end(SPARCv8Triples));
+    BiarchLibDirs.append(begin(SPARCv9LibDirs), end(SPARCv9LibDirs));
+    BiarchTripleAliases.append(begin(SPARCv9Triples), end(SPARCv9Triples));
+    break;
+  case llvm::Triple::sparcv9:
+    LibDirs.append(begin(SPARCv9LibDirs), end(SPARCv9LibDirs));
+    TripleAliases.append(begin(SPARCv9Triples), end(SPARCv9Triples));
+    BiarchLibDirs.append(begin(SPARCv8LibDirs), end(SPARCv8LibDirs));
+    BiarchTripleAliases.append(begin(SPARCv8Triples), end(SPARCv8Triples));
+    break;
+  case llvm::Triple::systemz:
+    LibDirs.append(begin(SystemZLibDirs), end(SystemZLibDirs));
+    TripleAliases.append(begin(SystemZTriples), end(SystemZTriples));
+    break;
+  default:
+    // By default, just rely on the standard lib directories and the original
+    // triple.
+    break;
+  }
+
+  // Always append the drivers target triple to the end, in case it doesn't
+  // match any of our aliases.
+  TripleAliases.push_back(TargetTriple.str());
+
+  // Also include the multiarch variant if it's different.
+  if (TargetTriple.str() != BiarchTriple.str())
+    BiarchTripleAliases.push_back(BiarchTriple.str());
+}
+
+bool Generic_GCC::GCCInstallationDetector::ScanGCCForMultilibs(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    StringRef Path, bool NeedsBiarchSuffix) {
+  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
+  DetectedMultilibs Detected;
+
+  // Android standalone toolchain could have multilibs for ARM and Thumb.
+  // Debian mips multilibs behave more like the rest of the biarch ones,
+  // so handle them there
+  if (isArmOrThumbArch(TargetArch) && TargetTriple.isAndroid()) {
+    // It should also work without multilibs in a simplified toolchain.
+    findAndroidArmMultilibs(D, TargetTriple, Path, Args, Detected);
+  } else if (TargetTriple.isMIPS()) {
+    if (!findMIPSMultilibs(D, TargetTriple, Path, Args, Detected))
+      return false;
+  } else if (TargetTriple.isRISCV()) {
+    findRISCVMultilibs(D, TargetTriple, Path, Args, Detected);
+  } else if (isMSP430(TargetArch)) {
+    findMSP430Multilibs(D, TargetTriple, Path, Args, Detected);
+  } else if (TargetArch == llvm::Triple::avr) {
+    // AVR has no multilibs.
+  } else if (!findBiarchMultilibs(D, TargetTriple, Path, Args,
+                                  NeedsBiarchSuffix, Detected)) {
+    return false;
+  }
+
+  Multilibs = Detected.Multilibs;
+  SelectedMultilib = Detected.SelectedMultilib;
+  BiarchSibling = Detected.BiarchSibling;
+
+  return true;
+}
+
+void Generic_GCC::GCCInstallationDetector::ScanLibDirForGCCTriple(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    const std::string &LibDir, StringRef CandidateTriple,
+    bool NeedsBiarchSuffix) {
+  llvm::Triple::ArchType TargetArch = TargetTriple.getArch();
+  // Locations relative to the system lib directory where GCC's triple-specific
+  // directories might reside.
+  struct GCCLibSuffix {
+    // Path from system lib directory to GCC triple-specific directory.
+    std::string LibSuffix;
+    // Path from GCC triple-specific directory back to system lib directory.
+    // This is one '..' component per component in LibSuffix.
+    StringRef ReversePath;
+    // Whether this library suffix is relevant for the triple.
+    bool Active;
+  } Suffixes[] = {
+      // This is the normal place.
+      {"gcc/" + CandidateTriple.str(), "../..", true},
+
+      // Debian puts cross-compilers in gcc-cross.
+      {"gcc-cross/" + CandidateTriple.str(), "../..",
+       TargetTriple.getOS() != llvm::Triple::Solaris},
+
+      // The Freescale PPC SDK has the gcc libraries in
+      // <sysroot>/usr/lib/<triple>/x.y.z so have a look there as well. Only do
+      // this on Freescale triples, though, since some systems put a *lot* of
+      // files in that location, not just GCC installation data.
+      {CandidateTriple.str(), "..",
+       TargetTriple.getVendor() == llvm::Triple::Freescale ||
+       TargetTriple.getVendor() == llvm::Triple::OpenEmbedded},
+
+      // Natively multiarch systems sometimes put the GCC triple-specific
+      // directory within their multiarch lib directory, resulting in the
+      // triple appearing twice.
+      {CandidateTriple.str() + "/gcc/" + CandidateTriple.str(), "../../..",
+       TargetTriple.getOS() != llvm::Triple::Solaris},
+
+      // Deal with cases (on Ubuntu) where the system architecture could be i386
+      // but the GCC target architecture could be (say) i686.
+      // FIXME: It may be worthwhile to generalize this and look for a second
+      // triple.
+      {"i386-linux-gnu/gcc/" + CandidateTriple.str(), "../../..",
+       (TargetArch == llvm::Triple::x86 &&
+        TargetTriple.getOS() != llvm::Triple::Solaris)},
+      {"i386-gnu/gcc/" + CandidateTriple.str(), "../../..",
+       (TargetArch == llvm::Triple::x86 &&
+        TargetTriple.getOS() != llvm::Triple::Solaris)}};
+
+  for (auto &Suffix : Suffixes) {
+    if (!Suffix.Active)
+      continue;
+
+    StringRef LibSuffix = Suffix.LibSuffix;
+    std::error_code EC;
+    for (llvm::vfs::directory_iterator
+             LI = D.getVFS().dir_begin(LibDir + "/" + LibSuffix, EC),
+             LE;
+         !EC && LI != LE; LI = LI.increment(EC)) {
+      StringRef VersionText = llvm::sys::path::filename(LI->path());
+      GCCVersion CandidateVersion = GCCVersion::Parse(VersionText);
+      if (CandidateVersion.Major != -1) // Filter obviously bad entries.
+        if (!CandidateGCCInstallPaths.insert(LI->path()).second)
+          continue; // Saw this path before; no need to look at it again.
+      if (CandidateVersion.isOlderThan(4, 1, 1))
+        continue;
+      if (CandidateVersion <= Version)
+        continue;
+
+      if (!ScanGCCForMultilibs(TargetTriple, Args, LI->path(),
+                               NeedsBiarchSuffix))
+        continue;
+
+      Version = CandidateVersion;
+      GCCTriple.setTriple(CandidateTriple);
+      // FIXME: We hack together the directory name here instead of
+      // using LI to ensure stable path separators across Windows and
+      // Linux.
+      GCCInstallPath = (LibDir + "/" + LibSuffix + "/" + VersionText).str();
+      GCCParentLibPath = (GCCInstallPath + "/../" + Suffix.ReversePath).str();
+      IsValid = true;
+    }
+  }
+}
+
+bool Generic_GCC::GCCInstallationDetector::ScanGentooConfigs(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    const SmallVectorImpl<StringRef> &CandidateTriples,
+    const SmallVectorImpl<StringRef> &CandidateBiarchTriples) {
+  for (StringRef CandidateTriple : CandidateTriples) {
+    if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple))
+      return true;
+  }
+
+  for (StringRef CandidateTriple : CandidateBiarchTriples) {
+    if (ScanGentooGccConfig(TargetTriple, Args, CandidateTriple, true))
+      return true;
+  }
+  return false;
+}
+
+bool Generic_GCC::GCCInstallationDetector::ScanGentooGccConfig(
+    const llvm::Triple &TargetTriple, const ArgList &Args,
+    StringRef CandidateTriple, bool NeedsBiarchSuffix) {
+  llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
+      D.getVFS().getBufferForFile(D.SysRoot + "/etc/env.d/gcc/config-" +
+                                  CandidateTriple.str());
+  if (File) {
+    SmallVector<StringRef, 2> Lines;
+    File.get()->getBuffer().split(Lines, "\n");
+    for (StringRef Line : Lines) {
+      Line = Line.trim();
+      // CURRENT=triple-version
+      if (!Line.consume_front("CURRENT="))
+        continue;
+      // Process the config file pointed to by CURRENT.
+      llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> ConfigFile =
+          D.getVFS().getBufferForFile(D.SysRoot + "/etc/env.d/gcc/" +
+                                      Line.str());
+      std::pair<StringRef, StringRef> ActiveVersion = Line.rsplit('-');
+      // List of paths to scan for libraries.
+      SmallVector<StringRef, 4> GentooScanPaths;
+      // Scan the Config file to find installed GCC libraries path.
+      // Typical content of the GCC config file:
+      // LDPATH="/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.x:/usr/lib/gcc/
+      // (continued from previous line) x86_64-pc-linux-gnu/4.9.x/32"
+      // MANPATH="/usr/share/gcc-data/x86_64-pc-linux-gnu/4.9.x/man"
+      // INFOPATH="/usr/share/gcc-data/x86_64-pc-linux-gnu/4.9.x/info"
+      // STDCXX_INCDIR="/usr/lib/gcc/x86_64-pc-linux-gnu/4.9.x/include/g++-v4"
+      // We are looking for the paths listed in LDPATH=... .
+      if (ConfigFile) {
+        SmallVector<StringRef, 2> ConfigLines;
+        ConfigFile.get()->getBuffer().split(ConfigLines, "\n");
+        for (StringRef ConfLine : ConfigLines) {
+          ConfLine = ConfLine.trim();
+          if (ConfLine.consume_front("LDPATH=")) {
+            // Drop '"' from front and back if present.
+            ConfLine.consume_back("\"");
+            ConfLine.consume_front("\"");
+            // Get all paths sperated by ':'
+            ConfLine.split(GentooScanPaths, ':', -1, /*AllowEmpty*/ false);
+          }
+        }
+      }
+      // Test the path based on the version in /etc/env.d/gcc/config-{tuple}.
+      std::string basePath = "/usr/lib/gcc/" + ActiveVersion.first.str() + "/"
+          + ActiveVersion.second.str();
+      GentooScanPaths.push_back(StringRef(basePath));
+
+      // Scan all paths for GCC libraries.
+      for (const auto &GentooScanPath : GentooScanPaths) {
+        std::string GentooPath = D.SysRoot + std::string(GentooScanPath);
+        if (D.getVFS().exists(GentooPath + "/crtbegin.o")) {
+          if (!ScanGCCForMultilibs(TargetTriple, Args, GentooPath,
+                                   NeedsBiarchSuffix))
+            continue;
+
+          Version = GCCVersion::Parse(ActiveVersion.second);
+          GCCInstallPath = GentooPath;
+          GCCParentLibPath = GentooPath + std::string("/../../..");
+          GCCTriple.setTriple(ActiveVersion.first);
+          IsValid = true;
+          return true;
+        }
+      }
+    }
+  }
+
+  return false;
+}
+
+Generic_GCC::Generic_GCC(const Driver &D, const llvm::Triple &Triple,
+                         const ArgList &Args)
+    : ToolChain(D, Triple, Args), GCCInstallation(D),
+      CudaInstallation(D, Triple, Args) {
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+}
+
+Generic_GCC::~Generic_GCC() {}
+
+Tool *Generic_GCC::getTool(Action::ActionClass AC) const {
+  switch (AC) {
+  case Action::PreprocessJobClass:
+    if (!Preprocess)
+      Preprocess.reset(new clang::driver::tools::gcc::Preprocessor(*this));
+    return Preprocess.get();
+  case Action::CompileJobClass:
+    if (!Compile)
+      Compile.reset(new tools::gcc::Compiler(*this));
+    return Compile.get();
+  default:
+    return ToolChain::getTool(AC);
+  }
+}
+
+Tool *Generic_GCC::buildAssembler() const {
+  return new tools::gnutools::Assembler(*this);
+}
+
+Tool *Generic_GCC::buildLinker() const { return new tools::gcc::Linker(*this); }
+
+void Generic_GCC::printVerboseInfo(raw_ostream &OS) const {
+  // Print the information about how we detected the GCC installation.
+  GCCInstallation.print(OS);
+  CudaInstallation.print(OS);
+}
+
+bool Generic_GCC::IsUnwindTablesDefault(const ArgList &Args) const {
+  return getArch() == llvm::Triple::x86_64;
+}
+
+bool Generic_GCC::isPICDefault() const {
+  switch (getArch()) {
+  case llvm::Triple::x86_64:
+    return getTriple().isOSWindows();
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el:
+    return true;
+  default:
+    return false;
+  }
+}
+
+bool Generic_GCC::isPIEDefault() const { return false; }
+
+bool Generic_GCC::isPICDefaultForced() const {
+  return getArch() == llvm::Triple::x86_64 && getTriple().isOSWindows();
+}
+
+bool Generic_GCC::IsIntegratedAssemblerDefault() const {
+  switch (getTriple().getArch()) {
+  case llvm::Triple::x86:
+  case llvm::Triple::x86_64:
+  case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_be:
+  case llvm::Triple::arm:
+  case llvm::Triple::armeb:
+  case llvm::Triple::avr:
+  case llvm::Triple::bpfel:
+  case llvm::Triple::bpfeb:
+  case llvm::Triple::thumb:
+  case llvm::Triple::thumbeb:
+  case llvm::Triple::ppc:
+  case llvm::Triple::ppc64:
+  case llvm::Triple::ppc64le:
+  case llvm::Triple::riscv32:
+  case llvm::Triple::riscv64:
+  case llvm::Triple::systemz:
+  case llvm::Triple::mips:
+  case llvm::Triple::mipsel:
+  case llvm::Triple::mips64:
+  case llvm::Triple::mips64el:
+  case llvm::Triple::msp430:
+    return true;
+  case llvm::Triple::sparc:
+  case llvm::Triple::sparcel:
+  case llvm::Triple::sparcv9:
+    if (getTriple().isOSFreeBSD() ||
+        getTriple().isOSSolaris())
+      return true;
+    return false;
+  default:
+    return false;
+  }
+}
+
+void Generic_GCC::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                               ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  switch (GetCXXStdlibType(DriverArgs)) {
+  case ToolChain::CST_Libcxx:
+    addLibCxxIncludePaths(DriverArgs, CC1Args);
+    break;
+
+  case ToolChain::CST_Libstdcxx:
+    addLibStdCxxIncludePaths(DriverArgs, CC1Args);
+    break;
+  }
+}
+
+static std::string DetectLibcxxIncludePath(llvm::vfs::FileSystem &vfs,
+                                           StringRef base) {
+  std::error_code EC;
+  int MaxVersion = 0;
+  std::string MaxVersionString;
+  for (llvm::vfs::directory_iterator LI = vfs.dir_begin(base, EC), LE;
+       !EC && LI != LE; LI = LI.increment(EC)) {
+    StringRef VersionText = llvm::sys::path::filename(LI->path());
+    int Version;
+    if (VersionText[0] == 'v' &&
+        !VersionText.slice(1, StringRef::npos).getAsInteger(10, Version)) {
+      if (Version > MaxVersion) {
+        MaxVersion = Version;
+        MaxVersionString = VersionText;
+      }
+    }
+  }
+  return MaxVersion ? (base + "/" + MaxVersionString).str() : "";
+}
+
+void
+Generic_GCC::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                   llvm::opt::ArgStringList &CC1Args) const {
+  const std::string& SysRoot = getDriver().SysRoot;
+  auto AddIncludePath = [&](std::string Path) {
+    std::string IncludePath = DetectLibcxxIncludePath(getVFS(), Path);
+    if (IncludePath.empty() || !getVFS().exists(IncludePath))
+      return false;
+    addSystemInclude(DriverArgs, CC1Args, IncludePath);
+    return true;
+  };
+  // Android never uses the libc++ headers installed alongside the toolchain,
+  // which are generally incompatible with the NDK libraries anyway.
+  if (!getTriple().isAndroid())
+    if (AddIncludePath(getDriver().Dir + "/../include/c++"))
+      return;
+  // If this is a development, non-installed, clang, libcxx will
+  // not be found at ../include/c++ but it likely to be found at
+  // one of the following two locations:
+  if (AddIncludePath(SysRoot + "/usr/local/include/c++"))
+    return;
+  if (AddIncludePath(SysRoot + "/usr/include/c++"))
+    return;
+}
+
+/// Helper to add the variant paths of a libstdc++ installation.
+bool Generic_GCC::addLibStdCXXIncludePaths(
+    Twine Base, Twine Suffix, StringRef GCCTriple, StringRef GCCMultiarchTriple,
+    StringRef TargetMultiarchTriple, Twine IncludeSuffix,
+    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
+  if (!getVFS().exists(Base + Suffix))
+    return false;
+
+  addSystemInclude(DriverArgs, CC1Args, Base + Suffix);
+
+  // The vanilla GCC layout of libstdc++ headers uses a triple subdirectory. If
+  // that path exists or we have neither a GCC nor target multiarch triple, use
+  // this vanilla search path.
+  if ((GCCMultiarchTriple.empty() && TargetMultiarchTriple.empty()) ||
+      getVFS().exists(Base + Suffix + "/" + GCCTriple + IncludeSuffix)) {
+    addSystemInclude(DriverArgs, CC1Args,
+                     Base + Suffix + "/" + GCCTriple + IncludeSuffix);
+  } else {
+    // Otherwise try to use multiarch naming schemes which have normalized the
+    // triples and put the triple before the suffix.
+    //
+    // GCC surprisingly uses *both* the GCC triple with a multilib suffix and
+    // the target triple, so we support that here.
+    addSystemInclude(DriverArgs, CC1Args,
+                     Base + "/" + GCCMultiarchTriple + Suffix + IncludeSuffix);
+    addSystemInclude(DriverArgs, CC1Args,
+                     Base + "/" + TargetMultiarchTriple + Suffix);
+  }
+
+  addSystemInclude(DriverArgs, CC1Args, Base + Suffix + "/backward");
+  return true;
+}
+
+bool
+Generic_GCC::addGCCLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                         llvm::opt::ArgStringList &CC1Args) const {
+  // Use GCCInstallation to know where libstdc++ headers are installed.
+  if (!GCCInstallation.isValid())
+    return false;
+
+  // By default, look for the C++ headers in an include directory adjacent to
+  // the lib directory of the GCC installation. Note that this is expect to be
+  // equivalent to '/usr/include/c++/X.Y' in almost all cases.
+  StringRef LibDir = GCCInstallation.getParentLibPath();
+  StringRef InstallDir = GCCInstallation.getInstallPath();
+  StringRef TripleStr = GCCInstallation.getTriple().str();
+  const Multilib &Multilib = GCCInstallation.getMultilib();
+  const std::string GCCMultiarchTriple = getMultiarchTriple(
+      getDriver(), GCCInstallation.getTriple(), getDriver().SysRoot);
+  const std::string TargetMultiarchTriple =
+      getMultiarchTriple(getDriver(), getTriple(), getDriver().SysRoot);
+  const GCCVersion &Version = GCCInstallation.getVersion();
+
+  // The primary search for libstdc++ supports multiarch variants.
+  if (addLibStdCXXIncludePaths(LibDir.str() + "/../include",
+                               "/c++/" + Version.Text, TripleStr,
+                               GCCMultiarchTriple, TargetMultiarchTriple,
+                               Multilib.includeSuffix(), DriverArgs, CC1Args))
+    return true;
+
+  // Otherwise, fall back on a bunch of options which don't use multiarch
+  // layouts for simplicity.
+  const std::string LibStdCXXIncludePathCandidates[] = {
+      // Gentoo is weird and places its headers inside the GCC install,
+      // so if the first attempt to find the headers fails, try these patterns.
+      InstallDir.str() + "/include/g++-v" + Version.Text,
+      InstallDir.str() + "/include/g++-v" + Version.MajorStr + "." +
+          Version.MinorStr,
+      InstallDir.str() + "/include/g++-v" + Version.MajorStr,
+  };
+
+  for (const auto &IncludePath : LibStdCXXIncludePathCandidates) {
+    if (addLibStdCXXIncludePaths(IncludePath, /*Suffix*/ "", TripleStr,
+                                 /*GCCMultiarchTriple*/ "",
+                                 /*TargetMultiarchTriple*/ "",
+                                 Multilib.includeSuffix(), DriverArgs, CC1Args))
+      return true;
+  }
+  return false;
+}
+
+void
+Generic_GCC::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                      llvm::opt::ArgStringList &CC1Args) const {
+  addGCCLibStdCxxIncludePaths(DriverArgs, CC1Args);
+}
+
+llvm::opt::DerivedArgList *
+Generic_GCC::TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef,
+                           Action::OffloadKind DeviceOffloadKind) const {
+
+  // If this tool chain is used for an OpenMP offloading device we have to make
+  // sure we always generate a shared library regardless of the commands the
+  // user passed to the host. This is required because the runtime library
+  // is required to load the device image dynamically at run time.
+  if (DeviceOffloadKind == Action::OFK_OpenMP) {
+    DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
+    const OptTable &Opts = getDriver().getOpts();
+
+    // Request the shared library. Given that these options are decided
+    // implicitly, they do not refer to any base argument.
+    DAL->AddFlagArg(/*BaseArg=*/nullptr, Opts.getOption(options::OPT_shared));
+    DAL->AddFlagArg(/*BaseArg=*/nullptr, Opts.getOption(options::OPT_fPIC));
+
+    // Filter all the arguments we don't care passing to the offloading
+    // toolchain as they can mess up with the creation of a shared library.
+    for (auto *A : Args) {
+      switch ((options::ID)A->getOption().getID()) {
+      default:
+        DAL->append(A);
+        break;
+      case options::OPT_shared:
+      case options::OPT_dynamic:
+      case options::OPT_static:
+      case options::OPT_fPIC:
+      case options::OPT_fno_PIC:
+      case options::OPT_fpic:
+      case options::OPT_fno_pic:
+      case options::OPT_fPIE:
+      case options::OPT_fno_PIE:
+      case options::OPT_fpie:
+      case options::OPT_fno_pie:
+        break;
+      }
+    }
+    return DAL;
+  }
+  return nullptr;
+}
+
+void Generic_ELF::anchor() {}
+
+void Generic_ELF::addClangTargetOptions(const ArgList &DriverArgs,
+                                        ArgStringList &CC1Args,
+                                        Action::OffloadKind) const {
+  if (!DriverArgs.hasFlag(options::OPT_fuse_init_array,
+                          options::OPT_fno_use_init_array, true))
+    CC1Args.push_back("-fno-use-init-array");
+}