+#ifndef __has_feature
+# define __has_feature(x) 0
+#endif
+
+/// \brief Does the compiler support r-value references?
+/// This implies that <utility> provides the one-argument std::move; it
+/// does not imply the existence of any other C++ library features.
+#if (__has_feature(cxx_rvalue_references) \
+ || defined(__GXX_EXPERIMENTAL_CXX0X__) \
+ || (defined(_MSC_VER) && _MSC_VER >= 1600))
+#define LLVM_HAS_RVALUE_REFERENCES 1
+#else
+#define LLVM_HAS_RVALUE_REFERENCES 0
+#endif
+
+/// \brief Does the compiler support r-value reference *this?
+///
+/// Sadly, this is separate from just r-value reference support because GCC
+/// implemented everything but this thus far. No release of GCC yet has support
+/// for this feature so it is enabled with Clang only.
+/// FIXME: This should change to a version check when GCC grows support for it.
+#if __has_feature(cxx_rvalue_references)
+#define LLVM_HAS_RVALUE_REFERENCE_THIS 1
+#else
+#define LLVM_HAS_RVALUE_REFERENCE_THIS 0
+#endif
+
+/// llvm_move - Expands to ::std::move if the compiler supports
+/// r-value references; otherwise, expands to the argument.
+#if LLVM_HAS_RVALUE_REFERENCES
+#define llvm_move(value) (::std::move(value))
+#else
+#define llvm_move(value) (value)
+#endif
+
+/// Expands to '&' if r-value references are supported.
+///
+/// This can be used to provide l-value/r-value overrides of member functions.
+/// The r-value override should be guarded by LLVM_HAS_RVALUE_REFERENCE_THIS
+#if LLVM_HAS_RVALUE_REFERENCE_THIS
+#define LLVM_LVALUE_FUNCTION &
+#else
+#define LLVM_LVALUE_FUNCTION
+#endif
+
+/// LLVM_DELETED_FUNCTION - Expands to = delete if the compiler supports it.
+/// Use to mark functions as uncallable. Member functions with this should
+/// be declared private so that some behavior is kept in C++03 mode.
+///
+/// class DontCopy {
+/// private:
+/// DontCopy(const DontCopy&) LLVM_DELETED_FUNCTION;
+/// DontCopy &operator =(const DontCopy&) LLVM_DELETED_FUNCTION;
+/// public:
+/// ...
+/// };
+#if (__has_feature(cxx_deleted_functions) \
+ || defined(__GXX_EXPERIMENTAL_CXX0X__))
+ // No version of MSVC currently supports this.
+#define LLVM_DELETED_FUNCTION = delete
+#else
+#define LLVM_DELETED_FUNCTION
+#endif
+
+/// LLVM_FINAL - Expands to 'final' if the compiler supports it.
+/// Use to mark classes or virtual methods as final.
+#if (__has_feature(cxx_override_control))
+#define LLVM_FINAL final
+#else
+#define LLVM_FINAL
+#endif
+
+/// LLVM_OVERRIDE - Expands to 'override' if the compiler supports it.
+/// Use to mark virtual methods as overriding a base class method.
+#if (__has_feature(cxx_override_control))
+#define LLVM_OVERRIDE override
+#else
+#define LLVM_OVERRIDE
+#endif
+