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

This reverts commit r307595. The commit had some issues that needed
to first be addressed in review.

llvm-svn: 307746
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e82f49849b259c9e6dd2b310fb5e46c0c2ee306a
diff --git a/src/locale.cpp b/src/locale.cpp
index e73e6d5..3b4c83a 100644
--- a/src/locale.cpp
+++ b/src/locale.cpp
@@ -28,7 +28,6 @@
 #define _CTYPE_DISABLE_MACROS
 #endif
 #include "cwctype"
-#include "__atomic_support"
 #include "__sso_allocator"
 #if defined(_LIBCPP_MSVCRT) || defined(__MINGW32__)
 #include "support/win32/locale_win32.h"
@@ -668,7 +667,7 @@
 void
 locale::id::__init()
 {
-    __id_ = __libcpp_sync_add_and_fetch(&__next_id, 1);
+    __id_ = __sync_add_and_fetch(&__next_id, 1);
 }
 
 // template <> class collate_byname<char>
diff --git a/src/support/runtime/exception_fallback.ipp b/src/support/runtime/exception_fallback.ipp
index cdf008a..69c06a9 100644
--- a/src/support/runtime/exception_fallback.ipp
+++ b/src/support/runtime/exception_fallback.ipp
@@ -9,7 +9,6 @@
 //===----------------------------------------------------------------------===//
 
 #include <cstdio>
-#include <__atomic_support>
 
 namespace std {
 
@@ -21,13 +20,13 @@
 unexpected_handler
 set_unexpected(unexpected_handler func) _NOEXCEPT
 {
-  return __libcpp_sync_lock_test_and_set(&__unexpected_handler, func);
+  return __sync_lock_test_and_set(&__unexpected_handler, func);
 }
 
 unexpected_handler
 get_unexpected() _NOEXCEPT
 {
-  return __libcpp_sync_fetch_and_add(&__unexpected_handler, (unexpected_handler)0);
+  return __sync_fetch_and_add(&__unexpected_handler, (unexpected_handler)0);
 
 }
 
@@ -42,13 +41,14 @@
 terminate_handler
 set_terminate(terminate_handler func) _NOEXCEPT
 {
-  return __libcpp_sync_lock_test_and_set(&__terminate_handler, func);
+  return __sync_lock_test_and_set(&__terminate_handler, func);
 }
 
 terminate_handler
 get_terminate() _NOEXCEPT
 {
-  return __libcpp_sync_fetch_and_add(&__terminate_handler, (terminate_handler)0);
+  return __sync_fetch_and_add(&__terminate_handler, (terminate_handler)0);
+
 }
 
 #ifndef __EMSCRIPTEN__ // We provide this in JS
diff --git a/src/support/runtime/new_handler_fallback.ipp b/src/support/runtime/new_handler_fallback.ipp
index 75f985d..b7092d5 100644
--- a/src/support/runtime/new_handler_fallback.ipp
+++ b/src/support/runtime/new_handler_fallback.ipp
@@ -8,8 +8,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include <__atomic_support>
-
 namespace std {
 
 _LIBCPP_SAFE_STATIC static std::new_handler __new_handler;
@@ -17,13 +15,13 @@
 new_handler
 set_new_handler(new_handler handler) _NOEXCEPT
 {
-    return __libcpp_sync_lock_test_and_set(&__new_handler, handler);
+    return __sync_lock_test_and_set(&__new_handler, handler);
 }
 
 new_handler
 get_new_handler() _NOEXCEPT
 {
-    return __libcpp_sync_fetch_and_add<new_handler>(&__new_handler, nullptr);
+    return __sync_fetch_and_add(&__new_handler, nullptr);
 }
 
 } // namespace std