Add V8_FINAL and V8_OVERRIDE macros for C++11 final/override.

src/globals.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 312 matching lines @@
 
 
 // FUNCTION_CAST<F>(addr) casts an address into a function
 // of type F. Used to invoke generated code from within C.
 template <typename F>
 F FUNCTION_CAST(Address addr) {
   return reinterpret_cast<F>(reinterpret_cast<intptr_t>(addr));
 }
 
 
+// Compiler feature detection.
+#if defined(__clang__)
+
+// Compatibility with older clang versions.
+# ifndef __has_extension
+# define __has_extension __has_feature
+# endif
+
+# if __has_extension(cxx_override_control)
+#  define V8_HAVE_CXX11_FINAL
+#  define V8_HAVE_CXX11_OVERRIDE
+# endif
+
+#elif defined(__GNUC__)
+
+// g++ requires -std=c++0x or -std=gnu++0x to support C++11 functionality
+// without warnings (functionality used by the macros below).  These modes
+// are detectable by checking whether __GXX_EXPERIMENTAL_CXX0X__ is defined or,
+// more standardly, by checking whether __cplusplus has a C++11 or greater
+// value. Current versions of g++ do not correctly set __cplusplus, so we check
+// both for forward compatibility.
+# if defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L
+#  if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#   define V8_HAVE_CXX11_OVERRIDE
+#   define V8_HAVE_CXX11_FINAL
+#  endif
+# else
+// '__final' is a non-C++11 GCC synonym for 'final', per GCC r176655.
+#  if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7)
+#   define V8_HAVE_GXX_FINAL
+#  endif
+# endif
+
+#elif defined(_MSC_VER)
+
+# if _MSC_VER >= 1400
+#  define V8_HAVE_CXX11_OVERRIDE
+// MSVC currently spells "final" as "sealed".
+#  define V8_HAVE_MSVC_SEALED
+# endif
+
+#endif
+
+
 #if __cplusplus >= 201103L
 #define DISALLOW_BY_DELETE = delete
 #else
 #define DISALLOW_BY_DELETE
 #endif
 
 
 // A macro to disallow the evil copy constructor and operator= functions
 // This should be used in the private: declarations for a class
 #define DISALLOW_COPY_AND_ASSIGN(TypeName)           \
@@ skipping 25 matching lines @@
 #endif
 #elif defined(_MSC_VER) && !defined(DEBUG)
 #define INLINE(header) __forceinline header
 #define NO_INLINE(header) header
 #else
 #define INLINE(header) inline header
 #define NO_INLINE(header) header
 #endif
 
 
+// Annotate a virtual method indicating it must be overriding a virtual
+// method in the parent class.
+// Use like:
+//   virtual void bar() V8_OVERRIDE;
+#if defined(V8_HAVE_CXX11_OVERRIDE)
+#define V8_OVERRIDE override
+#else
+#define V8_OVERRIDE
+#endif
+
+
+// Annotate a virtual method indicating that subclasses must not override it,
+// or annotate a class to indicate that it cannot be subclassed.
+// Use like:
+//   class B V8_FINAL : public A {};
+//   virtual void bar() V8_FINAL;
+#if defined(V8_HAVE_CXX11_FINAL)
+#define V8_FINAL final
+#elif defined(V8_HAVE_GXX_FINAL)
+#define V8_FINAL __final
+#elif defined(V8_HAVE_MSVC_SEALED)
+#define V8_FINAL sealed
+#else
+#define V8_FINAL
+#endif
+
+
 #if defined(__GNUC__) && __GNUC__ >= 4
 #define MUST_USE_RESULT __attribute__ ((warn_unused_result))
 #else
 #define MUST_USE_RESULT
 #endif
 
 
 // Define DISABLE_ASAN macros.
 #if defined(__has_feature)
 #if __has_feature(address_sanitizer)
@@ skipping 55 matching lines @@
 // the backend, so both modes are represented by the kStrictMode value.
 enum StrictModeFlag {
   kNonStrictMode,
   kStrictMode
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_GLOBALS_H_