[libc++] Refactoring __sync_* builtins; NFC (Reland)

Summary: Wrap __sync_* builtins with __libcpp_ functions to facility future customizations as atomic operations are unavailable on some targets.

Reviewers: danalbert, EricWF, jroelofs

Subscribers: joerg, llvm-commits

Differential Revision: https://reviews.llvm.org/D34918

llvm-svn: 307595

1 files changed, 5 insertions, 4 deletions

diff --git a/libcxx/include/__refstring b/libcxx/include/__refstring
index 7f417a03c49..de89b79a4b9 100644
--- a/libcxx/include/__refstring
+++ b/libcxx/include/__refstring
@@ -14,6 +14,7 @@
 #include <stdexcept>
 #include <cstddef>
 #include <cstring>
+#include <__atomic_support>
 #ifdef __APPLE__
 #include <dlfcn.h>
 #include <mach-o/dyld.h>
@@ -83,7 +84,7 @@ __libcpp_refstring::__libcpp_refstring(const __libcpp_refstring &s) _NOEXCEPT
     : __imp_(s.__imp_)
 {
     if (__uses_refcount())
-        __sync_add_and_fetch(&rep_from_data(__imp_)->count, 1);
+        __libcpp_sync_add_and_fetch(&rep_from_data(__imp_)->count, 1);
 }
 
 inline
@@ -92,10 +93,10 @@ __libcpp_refstring& __libcpp_refstring::operator=(__libcpp_refstring const& s) _
     struct _Rep_base *old_rep = rep_from_data(__imp_);
     __imp_ = s.__imp_;
     if (__uses_refcount())
-        __sync_add_and_fetch(&rep_from_data(__imp_)->count, 1);
+        __libcpp_sync_add_and_fetch(&rep_from_data(__imp_)->count, 1);
     if (adjust_old_count)
     {
-        if (__sync_add_and_fetch(&old_rep->count, count_t(-1)) < 0)
+        if (__libcpp_sync_add_and_fetch(&old_rep->count, count_t(-1)) < 0)
         {
             ::operator delete(old_rep);
         }
@@ -107,7 +108,7 @@ inline
 __libcpp_refstring::~__libcpp_refstring() {
     if (__uses_refcount()) {
         _Rep_base* rep = rep_from_data(__imp_);
-        if (__sync_add_and_fetch(&rep->count, count_t(-1)) < 0) {
+        if (__libcpp_sync_add_and_fetch(&rep->count, count_t(-1)) < 0) {
             ::operator delete(rep);
         }
     }