diff --git a/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.cpp b/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.cpp
index 7c9e9c0..4226188 100644
--- a/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.cpp
+++ b/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.cpp
@@ -1870,6 +1870,87 @@ bool FreeBSD::UseSjLjExceptions() const {
   }
 }
 
+/// \brief Helper to add the three variant paths for a libstdc++ installation.
+/*static*/ bool FreeBSD::addLibStdCXXIncludePaths(Twine Base, Twine TargetArchDir,
+                                                const ArgList &DriverArgs,
+                                                ArgStringList &CC1Args) {
+  if (!llvm::sys::fs::exists(Base))
+    return false;
+  addSystemInclude(DriverArgs, CC1Args, Base);
+  addSystemInclude(DriverArgs, CC1Args, Base + "/" + TargetArchDir);
+  addSystemInclude(DriverArgs, CC1Args, Base + "/backward");
+  return true;
+}
+
+/// \brief Helper to add an extra variant path for an (Ubuntu) multilib
+/// libstdc++ installation.
+/*static*/ bool FreeBSD::addLibStdCXXIncludePaths(Twine Base, Twine Suffix,
+                                                Twine TargetArchDir,
+                                                Twine MultiLibSuffix,
+                                                const ArgList &DriverArgs,
+                                                ArgStringList &CC1Args) {
+  if (!addLibStdCXXIncludePaths(Base+Suffix, TargetArchDir + MultiLibSuffix,
+                                DriverArgs, CC1Args))
+    return false;
+
+  addSystemInclude(DriverArgs, CC1Args, Base + "/" + TargetArchDir + Suffix
+                   + MultiLibSuffix);
+  return true;
+}
+
+void FreeBSD::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                         ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  // Check if libc++ has been enabled and provide its include paths if so.
+  if (GetCXXStdlibType(DriverArgs) == ToolChain::CST_Libcxx) {
+    // libc++ is always installed at a fixed path on Linux currently.
+    addSystemInclude(DriverArgs, CC1Args,
+                     getDriver().SysRoot + "/usr/include/c++/v1");
+    return;
+  }
+
+  // We need a detected GCC installation on Linux to provide libstdc++'s
+  // headers. We handled the libc++ case above.
+  if (!GCCInstallation.isValid())
+    return;
+
+  // 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 Version = GCCInstallation.getVersion().Text;
+  StringRef TripleStr = GCCInstallation.getTriple().str();
+
+  if (addLibStdCXXIncludePaths(LibDir.str() + "/../include",
+                               "/c++/" + Version.str(),
+                               TripleStr,
+                               GCCInstallation.getMultiarchSuffix(),
+                               DriverArgs, CC1Args))
+    return;
+
+  const std::string IncludePathCandidates[] = {
+    // Gentoo is weird and places its headers inside the GCC install, so if the
+    // first attempt to find the headers fails, try this pattern.
+    InstallDir.str() + "/include/g++-v4",
+    // Android standalone toolchain has C++ headers in yet another place.
+    LibDir.str() + "/../" + TripleStr.str() + "/include/c++/" + Version.str(),
+    // Freescale SDK C++ headers are directly in <sysroot>/usr/include/c++,
+    // without a subdirectory corresponding to the gcc version.
+    LibDir.str() + "/../include/c++",
+  };
+
+  for (unsigned i = 0; i < llvm::array_lengthof(IncludePathCandidates); ++i) {
+    if (addLibStdCXXIncludePaths(IncludePathCandidates[i], (TripleStr +
+                GCCInstallation.getMultiarchSuffix()),
+            DriverArgs, CC1Args))
+      break;
+  }
+}
+
 /// NetBSD - NetBSD tool chain which can call as(1) and ld(1) directly.
 
 NetBSD::NetBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
diff --git a/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.h b/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.h
index 3afd8dd..f7f87a2 100644
--- a/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.h
+++ b/llvm-3.3.src/tools/clang/lib/Driver/ToolChains.h
@@ -462,9 +462,22 @@ public:
   virtual bool IsObjCNonFragileABIDefault() const { return true; }
 
   virtual bool UseSjLjExceptions() const;
+
+  virtual void AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args) const;
 protected:
   virtual Tool *buildAssembler() const;
   virtual Tool *buildLinker() const;
+private:
+  static bool addLibStdCXXIncludePaths(Twine Base, Twine Suffix,
+                                       Twine TargetArchDir,
+                                       Twine MultiLibSuffix,
+                                       const ArgList &DriverArgs,
+                                       ArgStringList &CC1Args);
+  static bool addLibStdCXXIncludePaths(Twine Base, Twine TargetArchDir,
+                                       const ArgList &DriverArgs,
+                                       ArgStringList &CC1Args);
+
 };
 
 class LLVM_LIBRARY_VISIBILITY NetBSD : public Generic_ELF {