r261872 - Replace a compiler-specific approach to determining the presence of a getDecl() member function with one that does not require compiler-specific workarounds; NFC.
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Thu Feb 25 07:14:09 PST 2016
Author: aaronballman
Date: Thu Feb 25 09:14:09 2016
New Revision: 261872
URL: http://llvm.org/viewvc/llvm-project?rev=261872&view=rev
Log:
Replace a compiler-specific approach to determining the presence of a getDecl() member function with one that does not require compiler-specific workarounds; NFC.
Modified:
cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h
Modified: cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h?rev=261872&r1=261871&r2=261872&view=diff
==============================================================================
--- cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h (original)
+++ cfe/trunk/include/clang/ASTMatchers/ASTMatchersInternal.h Thu Feb 25 09:14:09 2016
@@ -569,32 +569,21 @@ bool matchesFirstInPointerRange(const Ma
return false;
}
-// Metafunction to determine if type T has a member called
-// getDecl.
-#if defined(_MSC_VER) && !defined(__clang__)
-// For MSVC, we use a weird nonstandard __if_exists statement, as it
-// is not standards-conformant enough to properly compile the standard
-// code below. (At least up through MSVC 2015 require this workaround)
-template <typename T> struct has_getDecl {
- __if_exists(T::getDecl) {
- enum { value = 1 };
- }
- __if_not_exists(T::getDecl) {
- enum { value = 0 };
- }
+// Metafunction to determine if type T has a member called getDecl.
+template <typename Ty>
+class has_getDecl {
+ typedef char yes[1];
+ typedef char no[2];
+
+ template <typename Inner>
+ static yes& test(Inner *I, decltype(I->getDecl()) * = nullptr);
+
+ template <typename>
+ static no& test(...);
+
+public:
+ static const bool value = sizeof(test<Ty>(nullptr)) == sizeof(yes);
};
-#else
-// There is a default template inheriting from "false_type". Then, a
-// partial specialization inherits from "true_type". However, this
-// specialization will only exist when the call to getDecl() isn't an
-// error -- it vanishes by SFINAE when the member doesn't exist.
-template <typename> struct type_sink_to_void { typedef void type; };
-template <typename T, typename = void> struct has_getDecl : std::false_type {};
-template <typename T>
-struct has_getDecl<
- T, typename type_sink_to_void<decltype(std::declval<T>().getDecl())>::type>
- : std::true_type {};
-#endif
/// \brief Matches overloaded operators with a specific name.
///
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