clang: add support for asmjs arch and Emscripten OS

lib/Driver/ToolChains.h

 //===--- ToolChains.h - ToolChain Implementations ---------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_H
@@ skipping 697 matching lines @@
   CXXStdlibType GetCXXStdlibType(const llvm::opt::ArgList &Args) const override;
 
   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);
 };
 
+// @LOCALMOD-START Emscripten
+/// EmscriptenToolChain - A toolchain for the Emscripten C/C++ to JS compiler.
+class LLVM_LIBRARY_VISIBILITY EmscriptenToolChain : public ToolChain {
+public:
+  EmscriptenToolChain(const Driver &D, const llvm::Triple &Triple,
+                      const llvm::opt::ArgList &Args);
+  ~EmscriptenToolChain();
+
+  bool IsMathErrnoDefault() const;

[jvoung (off chromium), 2015/03/20 17:07:07]

Indicate these methods are "override" ?

Why not just inline the bodies? Most of them do that except for TCEToolChain.

[JF, 2015/03/20 18:49:38]

Done.

+  bool IsObjCNonFragileABIDefault() const;
+  bool isPICDefault() const;
+  bool isPIEDefault() const;
+  bool isPICDefaultForced() const;
+};
+// @LOCALMOD-END Emscripten
+
 // @LOCALMOD-START
 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
@@ skipping 127 matching lines @@
                        llvm::opt::ArgStringList &CC1Args) const override;
   void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
                            llvm::opt::ArgStringList &CmdArgs) const override;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif