X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2Ftype_traits.h;h=7b97547be52af409574587e6d3c1e9ff321e9c65;hb=55907d1274ce715b92d584e305e0708e333a33c0;hp=241883a02cbb38ab7588daf3205aa2718982702c;hpb=ff12877a6f4db734cf0a156dc2ef815a839a79ec;p=oota-llvm.git

diff --git a/include/llvm/Support/type_traits.h b/include/llvm/Support/type_traits.h
index 241883a02cb..7b97547be52 100644
--- a/include/llvm/Support/type_traits.h
+++ b/include/llvm/Support/type_traits.h
@@ -21,6 +21,11 @@
 #include <cstddef>
 #include <utility>
 
+#ifndef __has_feature
+#define LLVM_DEFINED_HAS_FEATURE
+#define __has_feature(x) 0
+#endif
+
 // This is actually the conforming implementation which works with abstract
 // classes.  However, enough compilers have trouble with it that most will use
 // the one in boost/type_traits/object_traits.hpp. This implementation actually
@@ -58,15 +63,21 @@ struct is_class
 /// type can be copied around with memcpy instead of running ctors etc.
 template <typename T>
 struct isPodLike {
+#if __has_feature(is_trivially_copyable)
+  // If the compiler supports the is_trivially_copyable trait use it, as it
+  // matches the definition of isPodLike closely.
+  static const bool value = __is_trivially_copyable(T);
+#else
   // If we don't know anything else, we can (at least) assume that all non-class
   // types are PODs.
   static const bool value = !is_class<T>::value;
+#endif
 };
 
 // std::pair's are pod-like if their elements are.
 template<typename T, typename U>
 struct isPodLike<std::pair<T, U> > {
-  static const bool value = isPodLike<T>::value & isPodLike<U>::value;
+  static const bool value = isPodLike<T>::value && isPodLike<U>::value;
 };
   
 
@@ -121,46 +132,44 @@ template <> struct is_integral_impl<unsigned long long> : true_type {};
 template <typename T>
 struct is_integral : is_integral_impl<T> {};
 
-namespace dont_use {
-  // Form a return type that can only be instantiated with an integral or enum
-  // types (or with nullptr_t in C++11).
-  template <typename U, U u = U()> struct check_nontype_temp_param_return_type {
-    char c[2];
-  };
-  template <typename U>
-  check_nontype_temp_param_return_type<U> check_nontype_temp_param(U*);
-  template <typename U> char check_nontype_temp_param(...);
-
-  // Form a return type that can only be instantiated with nullptr_t in C++11
-  // mode. It's harmless in C++98 mode, but this allows us to filter nullptr_t
-  // when building in C++11 mode without having to detect that mode for each
-  // different compiler.
-  struct nonce {};
-  template <typename U, nonce* u = U()>
-  struct check_nullptr_t_like_return_type { char c[2]; };
-  template <typename U>
-  check_nullptr_t_like_return_type<U> check_nullptr_t_like(U*);
-  template <typename U> char check_nullptr_t_like(...);
-} // namespace dont_use
+/// \brief Metafunction to remove reference from a type.
+template <typename T> struct remove_reference { typedef T type; };
+template <typename T> struct remove_reference<T&> { typedef T type; };
+
+/// \brief Metafunction that determines whether the given type is a pointer
+/// type.
+template <typename T> struct is_pointer : false_type {};
+template <typename T> struct is_pointer<T*> : true_type {};
+template <typename T> struct is_pointer<T* const> : true_type {};
+template <typename T> struct is_pointer<T* volatile> : true_type {};
+template <typename T> struct is_pointer<T* const volatile> : true_type {};
 
 /// \brief Metafunction that determines whether the given type is either an
 /// integral type or an enumeration type.
 ///
 /// Note that this accepts potentially more integral types than we whitelist
-/// above for is_integral, it should accept essentially anything the compiler
-/// believes is an integral type.
-template <typename T> struct is_integral_or_enum {
+/// above for is_integral because it is based on merely being convertible
+/// implicitly to an integral type.
+template <typename T> class is_integral_or_enum {
+  // Provide an overload which can be called with anything implicitly
+  // convertible to an unsigned long long. This should catch integer types and
+  // enumeration types at least. We blacklist classes with conversion operators
+  // below.
+  static double check_int_convertible(unsigned long long);
+  static char check_int_convertible(...);
+
+  typedef typename remove_reference<T>::type UnderlyingT;
+  static UnderlyingT &nonce_instance;
+
+public:
   enum {
-    value = (sizeof(char) != sizeof(dont_use::check_nontype_temp_param<T>(0)) &&
-             sizeof(char) == sizeof(dont_use::check_nullptr_t_like<T>(0)))
+    value = (!is_class<UnderlyingT>::value && !is_pointer<UnderlyingT>::value &&
+             !is_same<UnderlyingT, float>::value &&
+             !is_same<UnderlyingT, double>::value &&
+             sizeof(char) != sizeof(check_int_convertible(nonce_instance)))
   };
 };
 
-/// \brief Metafunction that determines whether the given type is a pointer
-/// type.
-template <typename T> struct is_pointer : false_type {};
-template <typename T> struct is_pointer<T*> : true_type {};
-
 // enable_if_c - Enable/disable a template based on a metafunction
 template<bool Cond, typename T = void>
 struct enable_if_c {
@@ -204,4 +213,8 @@ struct conditional<false, T, F> { typedef F type; };
 
 }
 
+#ifdef LLVM_DEFINED_HAS_FEATURE
+#undef __has_feature
+#endif
+
 #endif