clang: add support for asmjs arch and Emscripten OS

lib/Driver/ToolChains.cpp

 //===--- ToolChains.cpp - ToolChain Implementations -----------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #include "ToolChains.h"
@@ skipping 2286 matching lines @@
   case 3:
     return "v3";
   case 2:
     return "v2";
   case 1:
     return "v1";
   }
 }
 // End Hexagon
 
+// @LOCALMOD-START Emscripten
+/// EmscriptenToolChain - A toolchain for the Emscripten C/C++ to JS compiler.
+EmscriptenToolChain::EmscriptenToolChain(const Driver &D,
+                                         const llvm::Triple &Triple,
+                                         const ArgList &Args)
+    : ToolChain(D, Triple, Args) {}
+EmscriptenToolChain::~EmscriptenToolChain() {}
+bool EmscriptenToolChain::IsMathErrnoDefault() const { return false; }
+bool EmscriptenToolChain::IsObjCNonFragileABIDefault() const { return true; }
+bool EmscriptenToolChain::isPICDefault() const { return false; }
+bool EmscriptenToolChain::isPIEDefault() const { return false; }
+bool EmscriptenToolChain::isPICDefaultForced() const { return false; }
+// @LOCALMOD-END Emscripten
+
 // @LOCALMOD-START
 /// 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();
@@ skipping 1314 matching lines @@
     StringRef(cl_include_dir).split(Dirs, StringRef(EnvPathSeparatorStr));
     ArrayRef<StringRef> DirVec(Dirs);
     addSystemIncludes(DriverArgs, CC1Args, DirVec);
   }
 }
 
 void XCore::AddCXXStdlibLibArgs(const ArgList &Args,
                                 ArgStringList &CmdArgs) const {
   // We don't output any lib args. This is handled by xcc.
 }