[Driver] Allow drivers to add multiple libc++ include paths

[phosek]

Summary

This allows toolchain drivers to add multiple libc++ include paths akin
to libstdc++. This is useful in multiarch setup when some headers might
be in target specific include directory. There should be no functional
change.

[rnk]

lgtm

clang/lib/Driver/ToolChains/BareMetal.h

public:
   const char *getDefaultLinker() const override { return "ld.lld"; }
 
   std::string getRuntimesDir() const;
   void AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                                  llvm::opt::ArgStringList &CC1Args) const override;
   void addClangTargetOptions(const llvm::opt::ArgList &DriverArgs,
                              llvm::opt::ArgStringList &CC1Args,
                              Action::OffloadKind DeviceOffloadKind) const override;
-  std::string findLibCxxIncludePath(ToolChain::CXXStdlibType LibType) const;
   void AddClangCXXStdlibIncludeArgs(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
   void AddLinkRuntimeLib(const llvm::opt::ArgList &Args,
                          llvm::opt::ArgStringList &CmdArgs) const;
 };

clang/lib/Driver/ToolChains/BareMetal.cpp

 }
 
 void BareMetal::addClangTargetOptions(const ArgList &DriverArgs,
                                       ArgStringList &CC1Args,
                                       Action::OffloadKind) const {
   CC1Args.push_back("-nostdsysteminc");
 }
 
-std::string BareMetal::findLibCxxIncludePath(CXXStdlibType LibType) const {
+void BareMetal::AddClangCXXStdlibIncludeArgs(
+    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
+      DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
   StringRef SysRoot = getDriver().SysRoot;
   if (SysRoot.empty())
-    return "";
+    return;
 
-  switch (LibType) {
+  switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx: {
     SmallString<128> Dir(SysRoot);
     llvm::sys::path::append(Dir, "include", "c++", "v1");
-    return Dir.str();
+    addSystemInclude(DriverArgs, CC1Args, Dir.str());
+    break;
   }
   case ToolChain::CST_Libstdcxx: {
     SmallString<128> Dir(SysRoot);
     llvm::sys::path::append(Dir, "include", "c++");
     std::error_code EC;
     Generic_GCC::GCCVersion Version = {"", -1, -1, -1, "", "", ""};
     // Walk the subdirs, and find the one with the newest gcc version:
     for (vfs::directory_iterator LI =
            getDriver().getVFS().dir_begin(Dir.str(), EC), LE;
          !EC && LI != LE; LI = LI.increment(EC)) {
       StringRef VersionText = llvm::sys::path::filename(LI->getName());
       auto CandidateVersion = Generic_GCC::GCCVersion::Parse(VersionText);
       if (CandidateVersion.Major == -1)
         continue;
       if (CandidateVersion <= Version)
         continue;
       Version = CandidateVersion;
     }
     if (Version.Major == -1)
-      return "";
+      return;
     llvm::sys::path::append(Dir, Version.Text);
-    return Dir.str();
-  }
+    addSystemInclude(DriverArgs, CC1Args, Dir.str());
+    break;
   }
-  llvm_unreachable("unhandled LibType");
   }
-
-void BareMetal::AddClangCXXStdlibIncludeArgs(
-    const ArgList &DriverArgs, ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdinc) ||
-      DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
-    return;
-
-  std::string Path = findLibCxxIncludePath(GetCXXStdlibType(DriverArgs));
-  if (!Path.empty())
-    addSystemInclude(DriverArgs, CC1Args, Path);
 }
 
 void BareMetal::AddCXXStdlibLibArgs(const ArgList &Args,
                                     ArgStringList &CmdArgs) const {
   switch (GetCXXStdlibType(Args)) {
   case ToolChain::CST_Libcxx:
     CmdArgs.push_back("-lc++");
     CmdArgs.push_back("-lc++abi");

clang/lib/Driver/ToolChains/CloudABI.h

public:
 
   bool IsMathErrnoDefault() const override { return false; }
   bool IsObjCNonFragileABIDefault() const override { return true; }
 
   CXXStdlibType
   GetCXXStdlibType(const llvm::opt::ArgList &Args) const override {
     return ToolChain::CST_Libcxx;
   }
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
   bool isPIEDefault() const override;
   SanitizerMask getSupportedSanitizers() const override;
   SanitizerMask getDefaultSanitizers() const override;
 
 protected:
   Tool *buildLinker() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_CLOUDABI_H

clang/lib/Driver/ToolChains/CloudABI.cpp

 CloudABI::CloudABI(const Driver &D, const llvm::Triple &Triple,
                    const ArgList &Args)
     : Generic_ELF(D, Triple, Args) {
   SmallString<128> P(getDriver().Dir);
   llvm::sys::path::append(P, "..", getTriple().str(), "lib");
   getFilePaths().push_back(P.str());
 }
 
-std::string CloudABI::findLibCxxIncludePath() const {
+void CloudABI::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                     llvm::opt::ArgStringList &CC1Args) const {
   SmallString<128> P(getDriver().Dir);
   llvm::sys::path::append(P, "..", getTriple().str(), "include/c++/v1");
-  return P.str();
+  addSystemInclude(DriverArgs, CC1Args, P.str());
 }
 
 void CloudABI::AddCXXStdlibLibArgs(const ArgList &Args,
                                    ArgStringList &CmdArgs) const {
   CmdArgs.push_back("-lc++");
   CmdArgs.push_back("-lc++abi");
   CmdArgs.push_back("-lunwind");
 }

clang/lib/Driver/ToolChains/Contiki.h

 namespace toolchains {
 
 class LLVM_LIBRARY_VISIBILITY Contiki : public Generic_ELF {
 public:
   Contiki(const Driver &D, const llvm::Triple &Triple,
           const llvm::opt::ArgList &Args);
 
   // No support for finding a C++ standard library yet.
-  std::string findLibCxxIncludePath() const override { return ""; }
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override {}
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override {}
 
   SanitizerMask getSupportedSanitizers() const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_CONTIKI_H

clang/lib/Driver/ToolChains/Gnu.h

protected:
   bool isTarget32Bit() const { return getTriple().isArch32Bit(); }
 
   // FIXME: This should be final, but the CrossWindows toolchain does weird
   // things that can't be easily generalized.
   void AddClangCXXStdlibIncludeArgs(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
-  virtual std::string findLibCxxIncludePath() const;
+  virtual void
+  addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                        llvm::opt::ArgStringList &CC1Args) const;
   virtual void
   addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                            llvm::opt::ArgStringList &CC1Args) const;
 
   bool addLibStdCXXIncludePaths(Twine Base, Twine Suffix, StringRef GCCTriple,
                                 StringRef GCCMultiarchTriple,
                                 StringRef TargetMultiarchTriple,
                                 Twine IncludeSuffix,

clang/lib/Driver/ToolChains/Gnu.cpp

 
 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: {
-    std::string Path = findLibCxxIncludePath();
-    if (!Path.empty())
-      addSystemInclude(DriverArgs, CC1Args, Path);
+  case ToolChain::CST_Libcxx:
+    addLibCxxIncludePaths(DriverArgs, CC1Args);
     break;
-  }
 
   case ToolChain::CST_Libstdcxx:
     addLibStdCxxIncludePaths(DriverArgs, CC1Args);
     break;
   }
 }
 
-std::string Generic_GCC::findLibCxxIncludePath() const {
+void
+Generic_GCC::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                   llvm::opt::ArgStringList &CC1Args) const {
   // FIXME: The Linux behavior would probaby be a better approach here.
-  return getDriver().SysRoot + "/usr/include/c++/v1";
+  addSystemInclude(DriverArgs, CC1Args,
+                   getDriver().SysRoot + "/usr/include/c++/v1");
 }
 
 void
 Generic_GCC::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                                       llvm::opt::ArgStringList &CC1Args) const {
   // By default, we don't assume we know where libstdc++ might be installed.
   // FIXME: If we have a valid GCCInstallation, use it.
 }

clang/lib/Driver/ToolChains/Haiku.h

 public:
   Haiku(const Driver &D, const llvm::Triple &Triple,
           const llvm::opt::ArgList &Args);
 
   bool isPIEDefault() const override {
     return getTriple().getArch() == llvm::Triple::x86_64;
   }
 
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_HAIKU_H

clang/lib/Driver/ToolChains/Haiku.cpp

 
 /// Haiku - Haiku tool chain which can call as(1) and ld(1) directly.
 
 Haiku::Haiku(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
   : Generic_ELF(D, Triple, Args) {
 
 }
 
-std::string Haiku::findLibCxxIncludePath() const {
-  return getDriver().SysRoot + "/system/develop/headers/c++/v1";
+void Haiku::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                  llvm::opt::ArgStringList &CC1Args) const {
+  addSystemInclude(DriverArgs, CC1Args,
+                   getDriver().SysRoot + "/system/develop/headers/c++/v1");
 }
 
 void Haiku::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                                      llvm::opt::ArgStringList &CC1Args) const {
   addLibStdCXXIncludePaths(getDriver().SysRoot, "/system/develop/headers/c++",
                            getTriple().str(), "", "", "", DriverArgs, CC1Args);
 }

clang/lib/Driver/ToolChains/Lanai.h

 
 class LLVM_LIBRARY_VISIBILITY LanaiToolChain : public Generic_ELF {
 public:
   LanaiToolChain(const Driver &D, const llvm::Triple &Triple,
                  const llvm::opt::ArgList &Args)
       : Generic_ELF(D, Triple, Args) {}
 
   // No support for finding a C++ standard library yet.
-  std::string findLibCxxIncludePath() const override { return ""; }
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override {}
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override {}
 
   bool IsIntegratedAssemblerDefault() const override { return true; }
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_LANAI_H

clang/lib/Driver/ToolChains/Linux.h

public:
   Linux(const Driver &D, const llvm::Triple &Triple,
         const llvm::opt::ArgList &Args);
 
   bool HasNativeLLVMSupport() const override;
 
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
   void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                           llvm::opt::ArgStringList &CC1Args) const override;
   void AddIAMCUIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                            llvm::opt::ArgStringList &CC1Args) const override;
   bool isPIEDefault() const override;

clang/lib/Driver/ToolChains/Linux.cpp

if (VersionText[0] == 'v' &&
         MaxVersion = Version;
         MaxVersionString = VersionText;
       }
     }
   }
   return MaxVersion ? (base + "/" + MaxVersionString).str() : "";
 }
 
-std::string Linux::findLibCxxIncludePath() const {
+void Linux::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                  llvm::opt::ArgStringList &CC1Args) const {
   const std::string LibCXXIncludePathCandidates[] = {
       DetectLibcxxIncludePath(getDriver().Dir + "/../include/c++"),
       // 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:
       DetectLibcxxIncludePath(getDriver().SysRoot + "/usr/local/include/c++"),
       DetectLibcxxIncludePath(getDriver().SysRoot + "/usr/include/c++") };
   for (const auto &IncludePath : LibCXXIncludePathCandidates) {
     if (IncludePath.empty() || !getVFS().exists(IncludePath))
       continue;
     // Use the first candidate that exists.
-    return IncludePath;
+    addSystemInclude(DriverArgs, CC1Args, IncludePath);
+    return;
   }
-  return "";
 }
 
 void Linux::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                                      llvm::opt::ArgStringList &CC1Args) const {
   // We need a detected GCC installation on Linux to provide libstdc++'s
   // headers.
   if (!GCCInstallation.isValid())
     return;

clang/lib/Driver/ToolChains/MipsLinux.h

MipsLLVMToolChain(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;
 
   CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
 
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
 
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 
   std::string getCompilerRT(const llvm::opt::ArgList &Args, StringRef Component,
                             bool Shared = false) const override;
 
   std::string computeSysRoot() const override;

clang/lib/Driver/ToolChains/MipsLinux.cpp

if (A) {
     if (Value != "libc++")
       getDriver().Diag(clang::diag::err_drv_invalid_stdlib_name)
           << A->getAsString(Args);
   }
 
   return ToolChain::CST_Libcxx;
 }
 
-std::string MipsLLVMToolChain::findLibCxxIncludePath() const {
+void MipsLLVMToolChain::addLibCxxIncludePaths(
+    const llvm::opt::ArgList &DriverArgs,
+    llvm::opt::ArgStringList &CC1Args) const {
   if (const auto &Callback = Multilibs.includeDirsCallback()) {
     for (std::string Path : Callback(SelectedMultilib)) {
       Path = getDriver().getInstalledDir() + Path + "/c++/v1";
       if (llvm::sys::fs::exists(Path)) {
-        return Path;
+        addSystemInclude(DriverArgs, CC1Args, Path);
+        return;
       }
     }
   }
-  return "";
 }
 
 void MipsLLVMToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
                                             ArgStringList &CmdArgs) const {
   assert((GetCXXStdlibType(Args) == ToolChain::CST_Libcxx) &&
          "Only -lc++ (aka libxx) is supported in this toolchain.");
 
   CmdArgs.push_back("-lc++");

clang/lib/Driver/ToolChains/Myriad.h

 public:
   MyriadToolChain(const Driver &D, const llvm::Triple &Triple,
                   const llvm::opt::ArgList &Args);
   ~MyriadToolChain() override;
 
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
   Tool *SelectTool(const JobAction &JA) const override;
   unsigned GetDefaultDwarfVersion() const override { return 2; }
   SanitizerMask getSupportedSanitizers() const override;
 
 protected:

clang/lib/Driver/ToolChains/Myriad.cpp

 MyriadToolChain::~MyriadToolChain() {}
 
 void MyriadToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
                                                 ArgStringList &CC1Args) const {
   if (!DriverArgs.hasArg(clang::driver::options::OPT_nostdinc))
     addSystemInclude(DriverArgs, CC1Args, getDriver().SysRoot + "/include");
 }
 
-std::string MyriadToolChain::findLibCxxIncludePath() const {
+void MyriadToolChain::addLibCxxIncludePaths(
+    const llvm::opt::ArgList &DriverArgs,
+    llvm::opt::ArgStringList &CC1Args) const {
   std::string Path(getDriver().getInstalledDir());
-  return Path + "/../include/c++/v1";
+  addSystemInclude(DriverArgs, CC1Args, Path + "/../include/c++/v1");
 }
 
 void MyriadToolChain::addLibStdCxxIncludePaths(
     const llvm::opt::ArgList &DriverArgs,
     llvm::opt::ArgStringList &CC1Args) const {
   StringRef LibDir = GCCInstallation.getParentLibPath();
   const GCCVersion &Version = GCCInstallation.getVersion();
   StringRef TripleStr = GCCInstallation.getTriple().str();

clang/lib/Driver/ToolChains/NaCl.h

 class LLVM_LIBRARY_VISIBILITY NaClToolChain : public Generic_ELF {
 public:
   NaClToolChain(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;
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      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 getTriple().getArch() == llvm::Triple::mipsel;

clang/lib/Driver/ToolChains/NaCl.cpp

 void NaClToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
                                         ArgStringList &CmdArgs) const {
   // Check for -stdlib= flags. We only support libc++ but this consumes the arg
   // if the value is libc++, and emits an error for other values.
   GetCXXStdlibType(Args);
   CmdArgs.push_back("-lc++");
 }
 
-std::string NaClToolChain::findLibCxxIncludePath() const {
+void NaClToolChain::addLibCxxIncludePaths(
+    const llvm::opt::ArgList &DriverArgs,
+    llvm::opt::ArgStringList &CC1Args) const {
   const Driver &D = getDriver();
 
   SmallString<128> P(D.Dir + "/../");
   switch (getTriple().getArch()) {
   case llvm::Triple::arm:
     llvm::sys::path::append(P, "arm-nacl/include/c++/v1");
-    return P.str();
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+    break;
   case llvm::Triple::x86:
     llvm::sys::path::append(P, "x86_64-nacl/include/c++/v1");
-    return P.str();
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+    break;
   case llvm::Triple::x86_64:
     llvm::sys::path::append(P, "x86_64-nacl/include/c++/v1");
-    return P.str();
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+    break;
   case llvm::Triple::mipsel:
     llvm::sys::path::append(P, "mipsel-nacl/include/c++/v1");
-    return P.str();
-  default:
-    return "";
+    addSystemInclude(DriverArgs, CC1Args, P.str());
+    break;
   }
 }
 
 ToolChain::CXXStdlibType
 NaClToolChain::GetCXXStdlibType(const ArgList &Args) const {
   if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
     StringRef Value = A->getValue();
     if (Value == "libc++")

clang/lib/Driver/ToolChains/NetBSD.h

public:
   NetBSD(const Driver &D, const llvm::Triple &Triple,
          const llvm::opt::ArgList &Args);
 
   bool IsMathErrnoDefault() const override { return false; }
   bool IsObjCNonFragileABIDefault() const override { return true; }
 
   CXXStdlibType GetDefaultCXXStdlibType() const override;
 
-  std::string findLibCxxIncludePath() const override;
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override;
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
   bool IsUnwindTablesDefault(const llvm::opt::ArgList &Args) const override {
     return true;
   }
 

clang/lib/Driver/ToolChains/NetBSD.cpp

case llvm::Triple::x86_64:
       return ToolChain::CST_Libcxx;
     default:
       break;
     }
   }
   return ToolChain::CST_Libstdcxx;
 }
 
-std::string NetBSD::findLibCxxIncludePath() const {
-  return getDriver().SysRoot + "/usr/include/c++/";
+void NetBSD::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
+                                   llvm::opt::ArgStringList &CC1Args) const {
+  addSystemInclude(DriverArgs, CC1Args,
+                   getDriver().SysRoot + "/usr/include/c++/");
 }
 
 void NetBSD::addLibStdCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
                                       llvm::opt::ArgStringList &CC1Args) const {
   addLibStdCXXIncludePaths(getDriver().SysRoot, "/usr/include/g++", "", "", "",
                            "", DriverArgs, CC1Args);
 }
 

clang/lib/Driver/ToolChains/PS4CPU.h

 namespace toolchains {
 
 class LLVM_LIBRARY_VISIBILITY PS4CPU : public Generic_ELF {
 public:
   PS4CPU(const Driver &D, const llvm::Triple &Triple,
          const llvm::opt::ArgList &Args);
 
   // No support for finding a C++ standard library yet.
-  std::string findLibCxxIncludePath() const override { return ""; }
+  void addLibCxxIncludePaths(
+      const llvm::opt::ArgList &DriverArgs,
+      llvm::opt::ArgStringList &CC1Args) const override {}
   void addLibStdCxxIncludePaths(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override {}
 
   bool IsMathErrnoDefault() const override { return false; }
   bool IsObjCNonFragileABIDefault() const override { return true; }
   bool HasNativeLLVMSupport() const override;
   bool isPICDefault() const override;