[PATCH] D47613: Mark __c11_atomic_load as const

[JF Bastien via Phabricator via cfe-commits]

jfb created this revision.
jfb added reviewers: EricWF, mclow.lists.
Herald added subscribers: cfe-commits, christof.

C++11 onwards specs the non-member functions atomic_load and atomic_load_explicit as taking the atomic<T> by const (potentially volatile) pointer. C11, in its infinite wisdom, decided to drop the const, and C17 will fix this with DR459 (the current draft forgot to fix B.16, but that’s not the normative part).

This patch fixes the libc++ version of the __c11_atomic_load builtins defined for GCC's compatibility sake.

Discussion: http://lists.llvm.org/pipermail/cfe-dev/2018-May/058129.html

rdar://problem/27426936


Repository:
  rCXX libc++

https://reviews.llvm.org/D47613

Files:
  include/atomic


Index: include/atomic
===================================================================
--- include/atomic
+++ include/atomic
@@ -698,16 +698,16 @@
 }
 
 template <typename _Tp>
-static inline _Tp __c11_atomic_load(volatile _Atomic(_Tp)* __a,
+static inline _Tp __c11_atomic_load(const volatile _Atomic(_Tp)* __a,
                                     memory_order __order) {
   _Tp __ret;
   __atomic_load(&__a->__a_value, &__ret,
                 __gcc_atomic::__to_gcc_order(__order));
   return __ret;
 }
 
 template <typename _Tp>
-static inline _Tp __c11_atomic_load(_Atomic(_Tp)* __a, memory_order __order) {
+static inline _Tp __c11_atomic_load(const _Atomic(_Tp)* __a, memory_order __order) {
   _Tp __ret;
   __atomic_load(&__a->__a_value, &__ret,
                 __gcc_atomic::__to_gcc_order(__order));


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