Add driver support for Native Client SDK

[dschuff]

Summary

Add Tool and ToolChain support for clang to target the NaCl OS using the NaCl
SDK for x86-32, x86-64 and ARM.

Includes nacltools::Assemble and Link which are derived from gnutools. They
are similar to Linux but different enought that they warrant their own class.
Also includes a NaCl_TC in ToolChains derived from Generic_ELF with library
and include paths suitable for an SDK and independent of the system tools.

[jvoung]

lib/Basic/Targets.cpp

3897

BTW, for the description string there was some test that did:

// RUN: %clang_cc1 -triple arm-nacl-gnueabi

wonder if it should just change to arm-nacl or arm-nacl-gnueabihf.

test/CodeGen/target-data.c

lib/Driver/ToolChains.cpp

2399

parameters don't seem lined up here and "AddClangCXXStdlibIncludeArgs"

2400

The "warning" part is a bit confusing on first read. You have to look at the implementation of "GetCXXStdlibType" to really know that there's warning.

2447

Is there anywhere that would warn if plain "gnueabi" was specified?

lib/Driver/Tools.cpp

7853

line up params

7872

Add a period at the end of the sentence.

7883

Technically there is OPT_pie too, comparing this to the gnutools version.

"""
OPT_dynamic looks like a darwin thing. Under the GCC man page:
-dynamic
-...

These options are passed to the Darwin linker. The Darwin linker man page describes them in detail.
"""

7917

Should explicitly check for x86-64 and have an llvm_unreachable or error for unexpected arches.

7946

Does a ref work?

const ToolChain::path_list &Paths = ...

7974

Might not need to mention PPAPI or phrase this differently, since it's not necessarily nacl-clang is not browser-specific.

[dschuff]

• jvoung review

[dschuff]

• missed duped comment

lib/Basic/Targets.cpp

3897

Just made it arm-nacl (the environment shouldn't affect the datalayout anyway)

lib/Driver/ToolChains.cpp

2399

Fixed

2400

made it clearer.

2447

This just covers the case if it's not specified. If gnueabi is specified that should override this default and be honored. Since the behavior of the regular arm compiler is just to allow the user to do that, maybe we should too?

lib/Driver/Tools.cpp

7853

done.

7872

done.

7883

Yeah... because we default to static, we wanted a way to sort of support doing dynamic, at least until we can make it the default. we don't support PIE at all yet.

7917

done. made it a diag since putting an unexpected arch on the command line actually does make it all the way to link here.

7946

yes done. im guessing that was probably the original intention since it's already const.

7974

done.

[jvoung]

otherwise LGTM

a little sad that a bunch of tools have to duplicate the "// Silence warning for "clang -g foo.o -o foo"" stuff... =/

lib/Driver/ToolChains.cpp

2447

If gnueabi is allowed, then perhaps the "StringRef tools::arm::getARMFloatABI()" code should check for it, rather than force hard-float.

lib/Driver/Tools.cpp

675

See reply about allowing gnueabi in ComputeEffectiveClangTriple... how does that interact with this then? Should this check for GNUEABI and set FloatABI = "soft"?

7874

params can be lined up

lib/Driver/Tools.h

514

Line up thy parameters.

[dschuff]

• jvoung review
• missed duped comment
• remove special snowflakes for AddARMTargetArgs and getARMFloatABI

lib/Driver/ToolChains.cpp

2447

OK, done. this means we can just fall into the default case and be more like Linux, both there and clang::AddARMTargetArgs() which is probably a good thing. I did those changes before adding this code to set the default in a later CL... it ended up being necessary for other reasons (https://codereview.chromium.org/838933004). This seemed like a bit more dubious change at the time but it's nice in that it's localized to NaCl_TC and that it allows fewer exceptional cases elsewhere.

I think this is fine and can land for now, but more generally, do agree that it's nice to allow environments other than gnueabihf and/or to do so without warning?

lib/Basic/Targets.cpp

NaClTargetInfo(const llvm::Triple &Triple) : OSTargetInfo<Target>(Triple) {
     this->LongLongWidth = 64;
     this->LongLongAlign = 64;
     this->SizeType = TargetInfo::UnsignedInt;
     this->PtrDiffType = TargetInfo::SignedInt;
     this->IntPtrType = TargetInfo::SignedInt;
     // RegParmMax is inherited from the underlying architecture
     this->LongDoubleFormat = &llvm::APFloat::IEEEdouble;
     if (Triple.getArch() == llvm::Triple::arm) {
-      this->DescriptionString =
-          "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S128";
+      // Handled in ARM's setABI().
     } else if (Triple.getArch() == llvm::Triple::x86) {
       this->DescriptionString = "e-m:e-p:32:32-i64:64-n8:16:32-S128";
     } else if (Triple.getArch() == llvm::Triple::x86_64) {
       this->DescriptionString = "e-m:e-p:32:32-i64:64-n8:16:32:64-S128";
     } else if (Triple.getArch() == llvm::Triple::mipsel) {
       // Handled on mips' setDescriptionString.
     } else {
       assert(Triple.getArch() == llvm::Triple::le32);
if (T.isOSBinFormatMachO()) {
       DescriptionString = "e"
                           "-m:w"
                           "-p:32:32"
                           "-i64:64"
                           "-v128:64:128"
                           "-a:0:32"
                           "-n32"
                           "-S64";
+    } else if (T.isOSNaCl()) {
+      assert(!BigEndian && "NaCl on ARM does not support big endian");
+      DescriptionString = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S128";
     } else {
       DescriptionString =
           BigEndian ? "E-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
                     : "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64";
     }
 
     // FIXME: Enumerated types are variable width in straight AAPCS.
   }

lib/Driver/Driver.cpp

case llvm::Triple::Minix:
       TC = new toolchains::Minix(*this, Target, Args);
       break;
     case llvm::Triple::Linux:
       if (Target.getArch() == llvm::Triple::hexagon)
         TC = new toolchains::Hexagon_TC(*this, Target, Args);
       else
         TC = new toolchains::Linux(*this, Target, Args);
       break;
+    case llvm::Triple::NaCl:
+      TC = new toolchains::NaCl_TC(*this, Target, Args);
+      break;
     case llvm::Triple::Solaris:
       TC = new toolchains::Solaris(*this, Target, Args);
       break;
     case llvm::Triple::Win32:
       switch (Target.getEnvironment()) {
       default:
         if (Target.isOSBinFormatELF())
           TC = new toolchains::Generic_ELF(*this, Target, Args);

lib/Driver/ToolChains.h

public:
   StringRef GetGCCLibAndIncVersion() const { return GCCLibAndIncVersion.Text; }
 
   static std::string GetGnuDir(const std::string &InstalledDir,
                                const llvm::opt::ArgList &Args);
 
   static StringRef GetTargetCPU(const llvm::opt::ArgList &Args);
 };
 
+class LLVM_LIBRARY_VISIBILITY NaCl_TC : public Generic_ELF {
+public:
+  NaCl_TC(const Driver &D, const llvm::Triple &Triple,
+          const llvm::opt::ArgList &Args);
+
+  void
+  AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
+                            llvm::opt::ArgStringList &CC1Args) const override;
+  void
+  AddClangCXXStdlibIncludeArgs(const llvm::opt::ArgList &DriverArgs,
+                               llvm::opt::ArgStringList &CC1Args) const override;
+
+  CXXStdlibType
+  GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
+
+  void
+  AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
+                      llvm::opt::ArgStringList &CmdArgs) const override;
+
+  bool
+  IsIntegratedAssemblerDefault() const override { return false; }
+
+  // Get the path to the file containing NaCl's ARM macros. It lives in NaCl_TC
+  // because the AssembleARM tool needs a const char * that it can pass around
+  // and the toolchain outlives all the jobs.
+  const char *GetNaClArmMacrosPath() const { return NaClArmMacrosPath.c_str(); }
+
+  std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
+                                          types::ID InputType) const override;
+  std::string Linker;
+
+protected:
+  Tool *buildLinker() const override;
+  Tool *buildAssembler() const override;
+
+private:
+  std::string NaClArmMacrosPath;
+};
+
 /// TCEToolChain - A tool chain using the llvm bitcode tools to perform
 /// all subcommands. See http://tce.cs.tut.fi for our peculiar target.
 class LLVM_LIBRARY_VISIBILITY TCEToolChain : public ToolChain {
 public:
   TCEToolChain(const Driver &D, const llvm::Triple &Triple,
                const llvm::opt::ArgList &Args);
   ~TCEToolChain();
 

lib/Driver/ToolChains.cpp

 void Generic_ELF::addClangTargetOptions(const ArgList &DriverArgs,
                                         ArgStringList &CC1Args) const {
   const Generic_GCC::GCCVersion &V = GCCInstallation.getVersion();
   bool UseInitArrayDefault =
       getTriple().getArch() == llvm::Triple::aarch64 ||
       getTriple().getArch() == llvm::Triple::aarch64_be ||
       (getTriple().getOS() == llvm::Triple::Linux &&
        (!V.isOlderThan(4, 7, 0) ||
-        getTriple().getEnvironment() == llvm::Triple::Android));
+        getTriple().getEnvironment() == llvm::Triple::Android)) ||
+      getTriple().getOS() == llvm::Triple::NaCl;
 
   if (DriverArgs.hasFlag(options::OPT_fuse_init_array,
                          options::OPT_fno_use_init_array,
                          UseInitArrayDefault))
     CC1Args.push_back("-fuse-init-array");
 }
 
 /// Hexagon Toolchain
StringRef Hexagon_TC::GetTargetCPU(const ArgList &Args)
   case 2:
     return "v2";
   case 1:
     return "v1";
   }
 }
 // End Hexagon
 
+/// NaCl Toolchain
+NaCl_TC::NaCl_TC(const Driver &D, const llvm::Triple &Triple,
+                 const ArgList &Args)
+  : Generic_ELF(D, Triple, Args) {
+
+  // Remove paths added by Generic_GCC. NaCl Toolchain cannot use the
+  // default paths, and must instead only use the paths provided
+  // with this toolchain based on architecture.
+  path_list& file_paths = getFilePaths();
+  path_list& prog_paths = getProgramPaths();
+
+  file_paths.clear();
+  prog_paths.clear();
+
+  // Path for library files (libc.a, ...)
+  std::string FilePath(getDriver().Dir + "/../");
+
+  // Path for tools (clang, ld, etc..)
+  std::string ProgPath(getDriver().Dir + "/../");
+
+  // Path for toolchain libraries (libgcc.a, ...)
+  std::string ToolPath(getDriver().ResourceDir + "/lib/");
+
+  switch(Triple.getArch()) {
+    case llvm::Triple::x86: {
+      file_paths.push_back(FilePath + "x86_64-nacl/lib32");
+      file_paths.push_back(FilePath + "x86_64-nacl/usr/lib32");
+      prog_paths.push_back(ProgPath + "x86_64-nacl/bin");
+      file_paths.push_back(ToolPath + "i686-nacl");
+      break;
+    }
+    case llvm::Triple::x86_64: {
+      file_paths.push_back(FilePath + "x86_64-nacl/lib");
+      file_paths.push_back(FilePath + "x86_64-nacl/usr/lib");
+      prog_paths.push_back(ProgPath + "x86_64-nacl/bin");
+      file_paths.push_back(ToolPath + "x86_64-nacl");
+      break;
+    }
+    case llvm::Triple::arm: {
+      file_paths.push_back(FilePath + "arm-nacl/lib");
+      file_paths.push_back(FilePath + "arm-nacl/usr/lib");
+      prog_paths.push_back(ProgPath + "arm-nacl/bin");
+      file_paths.push_back(ToolPath + "arm-nacl");
+      break;
+    }
+    default:
+      break;
+  }
+
+  // Use provided linker, not system linker
+  Linker = GetProgramPath("ld");
+  NaClArmMacrosPath = GetFilePath("nacl-arm-macros.s");
+}
+
+void NaCl_TC::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                        ArgStringList &CC1Args) const {
+  const Driver &D = getDriver();
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
+    return;
+
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    SmallString<128> P(D.ResourceDir);
+    llvm::sys::path::append(P, "include");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  }
+
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+  SmallString<128> P(D.Dir + "/../");
+  if (getTriple().getArch() == llvm::Triple::arm) {
+    llvm::sys::path::append(P, "arm-nacl/usr/include");
+  } else if (getTriple().getArch() == llvm::Triple::x86) {
+    llvm::sys::path::append(P, "x86_64-nacl/usr/include");
+  } else if (getTriple().getArch() == llvm::Triple::x86_64) {
+    llvm::sys::path::append(P, "x86_64-nacl/usr/include");
+  } else {
+    return;
+  }
+
+  addSystemInclude(DriverArgs, CC1Args, P.str());
+  llvm::sys::path::remove_filename(P);
+  llvm::sys::path::remove_filename(P);
+  llvm::sys::path::append(P, "include");
+  addSystemInclude(DriverArgs, CC1Args, P.str());
+}
+
+void NaCl_TC::AddCXXStdlibLibArgs(const ArgList &Args,
+                                    ArgStringList &CmdArgs) const {
+  // Allow and ignore -stdlib=libc++ without warning, but not libstdc++
+  GetCXXStdlibType(Args);
+  CmdArgs.push_back("-lc++");
+}
+
+void NaCl_TC::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                          ArgStringList &CC1Args) const {
+  const Driver &D = getDriver();
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  // Allow and ignore -stdlib=libc++ without warning, but not libstdc++
+  GetCXXStdlibType(DriverArgs);
+
+  if (getTriple().getArch() == llvm::Triple::arm) {
+    SmallString<128> P(D.Dir + "/../");
+    llvm::sys::path::append(P, "arm-nacl/include/c++/v1");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  } else if (getTriple().getArch() == llvm::Triple::x86) {
+    SmallString<128> P(D.Dir + "/../");
+    llvm::sys::path::append(P, "x86_64-nacl/include/c++/v1");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  } else if (getTriple().getArch() == llvm::Triple::x86_64) {
+    SmallString<128> P(D.Dir + "/../");
+    llvm::sys::path::append(P, "x86_64-nacl/include/c++/v1");
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+  }
+}
+
+ToolChain::CXXStdlibType NaCl_TC::GetCXXStdlibType(const ArgList &Args) const {
+  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value == "libc++")
+      return ToolChain::CST_Libcxx;
+    getDriver().Diag(diag::err_drv_invalid_stdlib_name)
+      << A->getAsString(Args);
+  }
+
+  return ToolChain::CST_Libcxx;
+}
+
+std::string NaCl_TC::ComputeEffectiveClangTriple(
+    const ArgList &Args, types::ID InputType) const {
+  llvm::Triple TheTriple(ComputeLLVMTriple(Args, InputType));
+  if (TheTriple.getArch() == llvm::Triple::arm &&
+      TheTriple.getEnvironment() == llvm::Triple::UnknownEnvironment)
+    TheTriple.setEnvironment(llvm::Triple::GNUEABIHF);
+  return TheTriple.getTriple();
+}
+
+Tool *NaCl_TC::buildLinker() const {
+  return new tools::nacltools::Link(*this);
+}
+
+Tool *NaCl_TC::buildAssembler() const {
+  if (getTriple().getArch() == llvm::Triple::arm)
+    return new tools::nacltools::AssembleARM(*this);
+  return new tools::gnutools::Assemble(*this);
+}
+// End NaCl
+
 /// TCEToolChain - A tool chain using the llvm bitcode tools to perform
 /// all subcommands. See http://tce.cs.tut.fi for our peculiar target.
 /// Currently does not support anything else but compilation.
 
 TCEToolChain::TCEToolChain(const Driver &D, const llvm::Triple& Triple,
                            const ArgList &Args)
   : ToolChain(D, Triple, Args) {
   // Path mangling to find libexec

lib/Driver/Tools.h

public:
 
     void ConstructJob(Compilation &C, const JobAction &JA,
                       const InputInfo &Output,
                       const InputInfoList &Inputs,
                       const llvm::opt::ArgList &TCArgs,
                       const char *LinkingOutput) const override;
   };
 }
+
+namespace nacltools {
+  class LLVM_LIBRARY_VISIBILITY AssembleARM : public gnutools::Assemble  {
+  public:
+    AssembleARM(const ToolChain &TC) : gnutools::Assemble(TC) {}
+
+    void ConstructJob(Compilation &C, const JobAction &JA,
+                      const InputInfo &Output,
+                      const InputInfoList &Inputs,
+                      const llvm::opt::ArgList &TCArgs,
+                      const char *LinkingOutput) const override;
+  };
+  class LLVM_LIBRARY_VISIBILITY Link : public Tool  {
+  public:
+    Link(const ToolChain &TC) : Tool("NaCl::Link", "linker", TC) {}
+
+    bool hasIntegratedCPP() const override { return false; }
+    bool isLinkJob() const override { return true; }
+
+    void ConstructJob(Compilation &C, const JobAction &JA,
+                              const InputInfo &Output,
+                              const InputInfoList &Inputs,
+                              const llvm::opt::ArgList &TCArgs,
+                              const char *LinkingOutput) const override;
+  };
+}
+
   /// minix -- Directly call GNU Binutils assembler and linker
 namespace minix {
   class LLVM_LIBRARY_VISIBILITY Assemble : public GnuTool  {
   public:
     Assemble(const ToolChain &TC) : GnuTool("minix::Assemble", "assembler",
                                          TC) {}
 
     bool hasIntegratedCPP() const override { return false; }

lib/Driver/Tools.cpp

case llvm::Triple::FreeBSD:
         break;
       default:
         // FreeBSD defaults to soft float
         FloatABI = "soft";
         break;
       }
       break;
 
+    case llvm::Triple::NaCl:
+      FloatABI = "hard";
+      break;
+
     default:
       switch(Triple.getEnvironment()) {
       case llvm::Triple::GNUEABIHF:
         FloatABI = "hard";
         break;
       case llvm::Triple::GNUEABI:
         FloatABI = "softfp";
         break;
if (Triple.getEnvironment() == llvm::Triple::EABI ||
         StringRef(CPUName).startswith("cortex-m")) {
       ABIName = "aapcs";
     } else {
       ABIName = "apcs-gnu";
     }
   } else if (Triple.isOSWindows()) {
     // FIXME: this is invalid for WindowsCE
     ABIName = "aapcs";
+  } else if (Triple.isOSNaCl()) {
+    ABIName = "aapcs-linux";
   } else {
     // Select the default based on the platform.
     switch(Triple.getEnvironment()) {
     case llvm::Triple::Android:
     case llvm::Triple::GNUEABI:
     case llvm::Triple::GNUEABIHF:
       ABIName = "aapcs-linux";
       break;
if (!Args.hasArg(options::OPT_nostartfiles)) {
         CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
     }
   }
 
   C.addCommand(
       llvm::make_unique<Command>(JA, *this, ToolChain.Linker.c_str(), CmdArgs));
 }
 
+
+// NaCl ARM assembly (inline or standalone) can be written with a set of macros
+// for the various SFI requirements like register masking. The assembly tool
+// inserts the file containing the macros as an input into all the assembly
+// jobs.
+void nacltools::AssembleARM::ConstructJob(Compilation &C, const JobAction &JA,
+                                       const InputInfo &Output,
+                                       const InputInfoList &Inputs,
+                                       const ArgList &Args,
+                                       const char *LinkingOutput) const {
+  const toolchains::NaCl_TC& ToolChain =
+    static_cast<const toolchains::NaCl_TC&>(getToolChain());
+  InputInfo NaClMacros(ToolChain.GetNaClArmMacrosPath(), types::TY_PP_Asm,
+                       "nacl-arm-macros.s");
+  InputInfoList NewInputs;
+  NewInputs.push_back(NaClMacros);
+  NewInputs.append(Inputs.begin(), Inputs.end());
+  gnutools::Assemble::ConstructJob(C, JA, Output, NewInputs, Args,
+                                   LinkingOutput);
+}
+
+
+// This is quite similar to gnutools::link::ConstructJob with changes that
+// we use static by default, do not yet support sanitizers or LTO, and a few
+// others. Eventually we can support more of that and hopefully migrate back
+// to gnutools::link
+void nacltools::Link::ConstructJob(Compilation &C, const JobAction &JA,
+                                  const InputInfo &Output,
+                                  const InputInfoList &Inputs,
+                                  const ArgList &Args,
+                                  const char *LinkingOutput) const {
+
+  const toolchains::NaCl_TC& ToolChain =
+    static_cast<const toolchains::NaCl_TC&>(getToolChain());
+  const Driver &D = ToolChain.getDriver();
+  const bool IsStatic =
+    !Args.hasArg(options::OPT_dynamic) &&
+    !Args.hasArg(options::OPT_shared);
+
+  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 (Args.hasArg(options::OPT_rdynamic))
+    CmdArgs.push_back("-export-dynamic");
+
+  if (Args.hasArg(options::OPT_s))
+    CmdArgs.push_back("-s");
+
+  // NaCl_TC doesn't have ExtraOpts like Linux; the only relevant flag from
+  // there is --build-id, which we do want.
+  CmdArgs.push_back("--build-id");
+
+  if (!IsStatic)
+    CmdArgs.push_back("--eh-frame-hdr");
+
+  CmdArgs.push_back("-m");
+  if (ToolChain.getArch() == llvm::Triple::x86)
+    CmdArgs.push_back("elf_i386_nacl");
+  else if (ToolChain.getArch() == llvm::Triple::arm)
+    CmdArgs.push_back("armelf_nacl");
+  else
+    CmdArgs.push_back("elf_x86_64_nacl");
+
+  if (IsStatic)
+    CmdArgs.push_back("-static");
+  else if (Args.hasArg(options::OPT_shared))
+    CmdArgs.push_back("-shared");
+
+  CmdArgs.push_back("-o");
+  CmdArgs.push_back(Output.getFilename());
+  if (!Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared))
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt1.o")));
+    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crti.o")));
+
+    const char *crtbegin;
+    if (IsStatic)
+      crtbegin = "crtbeginT.o";
+    else if (Args.hasArg(options::OPT_shared))
+      crtbegin = "crtbeginS.o";
+    else
+      crtbegin = "crtbegin.o";
+    CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtbegin)));
+  }
+
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  Args.AddAllArgs(CmdArgs, options::OPT_u);
+
+  const ToolChain::path_list Paths = ToolChain.getFilePaths();
+
+  for (const auto &Path : Paths)
+    CmdArgs.push_back(Args.MakeArgString(StringRef("-L") + Path));
+
+  if (Args.hasArg(options::OPT_Z_Xlinker__no_demangle))
+    CmdArgs.push_back("--no-demangle");
+
+  AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
+
+  if (D.CCCIsCXX() &&
+      !Args.hasArg(options::OPT_nostdlib) &&
+      !Args.hasArg(options::OPT_nodefaultlibs)) {
+    bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
+      !IsStatic;
+    if (OnlyLibstdcxxStatic)
+      CmdArgs.push_back("-Bstatic");
+    ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
+    if (OnlyLibstdcxxStatic)
+      CmdArgs.push_back("-Bdynamic");
+    CmdArgs.push_back("-lm");
+  }
+
+  if (!Args.hasArg(options::OPT_nostdlib)) {
+    if (!Args.hasArg(options::OPT_nodefaultlibs)) {
+      // Always use groups, since it has no effect on dynamic libraries.
+      CmdArgs.push_back("--start-group");
+      CmdArgs.push_back("-lc");
+      // libc++ and PPAPI programs always require libpthread, so just always
+      // include it in the group for C++.
+      if (Args.hasArg(options::OPT_pthread) ||
+          Args.hasArg(options::OPT_pthreads) ||
+          D.CCCIsCXX()) {
+        CmdArgs.push_back("-lpthread");
+      }
+
+      CmdArgs.push_back("-lgcc");
+      CmdArgs.push_back("--as-needed");
+      if (IsStatic)
+        CmdArgs.push_back("-lgcc_eh");
+      else
+        CmdArgs.push_back("-lgcc_s");
+      CmdArgs.push_back("--no-as-needed");
+      CmdArgs.push_back("--end-group");
+    }
+
+    if (!Args.hasArg(options::OPT_nostartfiles)) {
+      const char *crtend;
+      if (Args.hasArg(options::OPT_shared))
+        crtend = "crtendS.o";
+      else
+        crtend = "crtend.o";
+
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(crtend)));
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
+    }
+  }
+
+  C.addCommand(llvm::make_unique<Command>(JA, *this,
+                                          ToolChain.Linker.c_str(), CmdArgs));
+}
+
+
 void minix::Assemble::ConstructJob(Compilation &C, const JobAction &JA,
                                    const InputInfo &Output,
                                    const InputInfoList &Inputs,
                                    const ArgList &Args,
                                    const char *LinkingOutput) const {
   claimNoWarnArgs(Args);
   ArgStringList CmdArgs;
 

lib/Frontend/InitHeaderSearch.cpp

void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
 
   if (HSOpts.UseStandardSystemIncludes) {
     switch (os) {
     case llvm::Triple::CloudABI:
     case llvm::Triple::FreeBSD:
     case llvm::Triple::NetBSD:
     case llvm::Triple::OpenBSD:
     case llvm::Triple::Bitrig:
+    case llvm::Triple::NaCl:
       break;
     default:
       // FIXME: temporary hack: hard-coded paths.
       AddPath("/usr/local/include", System, false);
       break;
     }
   }
 
#endif
     break;
   default:
     break;
   }
 
   switch (os) {
   case llvm::Triple::CloudABI:
   case llvm::Triple::RTEMS:
+  case llvm::Triple::NaCl:
     break;
   default:
     AddPath("/usr/include", ExternCSystem, false);
     break;
   }
 }
 
 void InitHeaderSearch::

test/Driver/nacl-direct.c

+// Test clang changes for NaCl Support including:
+//    include paths, library paths, emulation, default static
+//
+// RUN: %clang -### -o %t.o %s 2>&1 \
+// RUN:     -target i686-unknown-nacl \
+// RUN:   | FileCheck --check-prefix=CHECK-I686 %s
+// CHECK-I686: {{.*}}clang{{.*}}" "-cc1"
+// CHECK-I686: "-fuse-init-array"
+// CHECK-I686: "-target-cpu" "pentium4"
+// CHECK-I686: "-resource-dir" "{{.*}}/lib/clang/[[VER:[0-9.]+]]"
+// CHECK-I686: "-internal-isystem" "{{.*}}/../lib/clang/[[VER]]/include"
+// CHECK-I686: "-internal-isystem" "{{.*}}/../x86_64-nacl/usr/include"
+// CHECK-I686: "-internal-isystem" "{{.*}}/../x86_64-nacl/include"
+// CHECK-I686: /as" "--32"
+// CHECK-I686: /ld"
+// CHECK-I686: "--build-id"
+// CHECK-I686: "-m" "elf_i386_nacl"
+// CHECK-I686: "-static"
+// CHECK-I686: "-L{{.*}}/../x86_64-nacl/lib32"
+// CHECK-I686: "-L{{.*}}/../x86_64-nacl/usr/lib32"
+// CHECK-I686: "-L{{.*}}/../lib/clang/[[VER]]/lib/i686-nacl"
+// CHECK-I686-NOT: -lpthread
+//
+// RUN: %clang -### -o %t.o %s 2>&1 \
+// RUN:     -target x86_64-unknown-nacl \
+// RUN:   | FileCheck --check-prefix=CHECK-x86_64 %s
+// CHECK-x86_64: {{.*}}clang{{.*}}" "-cc1"
+// CHECK-x86_64: "-fuse-init-array"
+// CHECK-x86_64: "-target-cpu" "x86-64"
+// CHECK-x86_64: "-resource-dir" "{{.*}}/lib/clang/[[VER:[0-9.]+]]"
+// CHECK-x86_64: "-internal-isystem" "{{.*}}/../lib/clang/[[VER]]/include"
+// CHECK-x86_64: "-internal-isystem" "{{.*}}/../x86_64-nacl/usr/include"
+// CHECK-x86_64: "-internal-isystem" "{{.*}}/../x86_64-nacl/include"
+// CHECK-x86_64: /as" "--64"
+// CHECK-x86_64: /ld"
+// CHECK-x86_64: "--build-id"
+// CHECK-x86_64: "-m" "elf_x86_64_nacl"
+// CHECK-x86_64: "-static"
+// CHECK-x86_64: "-L{{.*}}/../x86_64-nacl/lib"
+// CHECK-x86_64: "-L{{.*}}/../x86_64-nacl/usr/lib"
+// CHECK-x86_64: "-L{{.*}}/../lib/clang/[[VER]]/lib/x86_64-nacl"
+// CHECK-X86_64-NOT: -lpthread
+//
+// RUN: %clang -### -o %t.o %s 2>&1 \
+// RUN:     -target armv7a-unknown-nacl-gnueabihf \
+// RUN:   | FileCheck --check-prefix=CHECK-ARM %s
+// CHECK-ARM: {{.*}}clang{{.*}}" "-cc1"
+// CHECK-ARM: "-fuse-init-array"
+// CHECK-ARM: "-target-cpu" "cortex-a8"
+// CHECK-ARM: "-target-abi" "aapcs-linux"
+// CHECK-ARM: "-mfloat-abi" "hard"
+// CHECK-ARM: "-resource-dir" "{{.*}}/lib/clang/[[VER:[0-9.]+]]"
+// CHECK-ARM: "-internal-isystem" "{{.*}}/../lib/clang/[[VER]]/include"
+// CHECK-ARM: "-internal-isystem" "{{.*}}/../arm-nacl/usr/include"
+// CHECK-ARM: "-internal-isystem" "{{.*}}/../arm-nacl/include"
+// CHECK-ARM: /as"
+// CHECK-ARM: /ld"
+// CHECK-ARM: "--build-id"
+// CHECK-ARM: "-m" "armelf_nacl"
+// CHECK-ARM: "-static"
+// CHECK-ARM: "-L{{.*}}/../arm-nacl/lib"
+// CHECK-ARM: "-L{{.*}}/../arm-nacl/usr/lib"
+// CHECK-ARM: "-L{{.*}}/../lib/clang/[[VER]]/lib/arm-nacl"
+// CHECK-ARM-NOT: -lpthread
+
+// Check that even when the target arch is just "arm" (as will be the case when
+// it is inferred from the binary name) that we get the right ABI flags
+// RUN: %clang -### -o %t.o %s 2>&1 \
+// RUN:     -target arm-nacl \
+// RUN:   | FileCheck --check-prefix=CHECK-ARM-NOV7 %s
+// CHECK-ARM-NOV7: "-triple" "armv7--nacl-gnueabihf"
+// CHECK-ARM-NOV7: "-target-abi" "aapcs-linux"
+// CHECK-ARM-NOV7: "-mfloat-abi" "hard"
+
+// Test clang c++ include dirs and link line when using clang++
+
+// RUN: %clangxx -### -o %t.o %s 2>&1 \
+// RUN:     -target armv7a-unknown-nacl-gnueabihf \
+// RUN:   | FileCheck --check-prefix=CHECK-ARM-CXX %s
+// CHECK-ARM-CXX: {{.*}}clang{{.*}}" "-cc1"
+// CHECK-ARM-CXX: "-resource-dir" "{{.*}}/lib/clang/[[VER:[0-9.]+]]"
+// CHECK-ARM-CXX: "-internal-isystem" "{{.*}}/../arm-nacl/include/c++/v1"
+// CHECK-ARM-CXX: "-internal-isystem" "{{.*}}/../lib/clang/[[VER]]/include"
+// CHECK-ARM-CXX: "-internal-isystem" "{{.*}}/../arm-nacl/usr/include"
+// CHECK-ARM-CXX: "-internal-isystem" "{{.*}}/../arm-nacl/include"
+// CHECK-ARM-CXX: "-lpthread"
+
+// RUN: %clangxx -### -o %t.o %s 2>&1 \
+// RUN:     -target i686-unknown-nacl \
+// RUN:   | FileCheck --check-prefix=CHECK-I686-CXX %s
+// CHECK-I686-CXX: {{.*}}clang{{.*}}" "-cc1"
+// CHECK-I686-CXX: "-resource-dir" "{{.*}}/lib/clang/[[VER:[0-9.]+]]"
+// CHECK-I686-CXX: "-internal-isystem" "{{.*}}/../x86_64-nacl/include/c++/v1"
+// CHECK-I686-CXX: "-internal-isystem" "{{.*}}/../lib/clang/[[VER]]/include"
+// CHECK-I686-CXX: "-internal-isystem" "{{.*}}/../x86_64-nacl/usr/include"
+// CHECK-I686-CXX: "-internal-isystem" "{{.*}}/../x86_64-nacl/include"
+// CHECK-I686-CXX: "-lpthread"
+
+// RUN: %clangxx -### -o %t.o %s 2>&1 \
+// RUN:     -target x86_64-unknown-nacl \
+// RUN:   | FileCheck --check-prefix=CHECK-x86_64-CXX %s
+// CHECK-x86_64-CXX: {{.*}}clang{{.*}}" "-cc1"
+// CHECK-x86_64-CXX: "-resource-dir" "{{.*}}/lib/clang/[[VER:[0-9.]+]]"
+// CHECK-x86_64-CXX: "-internal-isystem" "{{.*}}/../x86_64-nacl/include/c++/v1"
+// CHECK-x86_64-CXX: "-internal-isystem" "{{.*}}/../lib/clang/[[VER]]/include"
+// CHECK-x86_64-CXX: "-internal-isystem" "{{.*}}/../x86_64-nacl/usr/include"
+// CHECK-x86_64-CXX: "-internal-isystem" "{{.*}}/../x86_64-nacl/include"
+// CHECK-x86_64-CXX: "-lpthread"