hxy9243 set the repository for this revision to rL LLVM.
hxy9243 updated this revision to Diff 82958.
hxy9243 added a comment.
Move the header back in its place, and only copy over necessary parts. Now call
__atomic_add_fetch from inside the functions.
Repository:
rL LLVM
https://reviews.llvm.org/D24991
Files:
libcxx/include/memory
libcxx/src/memory.cpp
Index: libcxx/src/memory.cpp
===================================================================
--- libcxx/src/memory.cpp
+++ libcxx/src/memory.cpp
@@ -17,28 +17,6 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-namespace
-{
-
-// NOTE: Relaxed and acq/rel atomics (for increment and decrement respectively)
-// should be sufficient for thread safety.
-// See https://llvm.org/bugs/show_bug.cgi?id=22803
-template <class T>
-inline T
-increment(T& t) _NOEXCEPT
-{
- return __libcpp_atomic_add(&t, 1, _AO_Relaxed);
-}
-
-template <class T>
-inline T
-decrement(T& t) _NOEXCEPT
-{
- return __libcpp_atomic_add(&t, -1, _AO_Acq_Rel);
-}
-
-} // namespace
-
const allocator_arg_t allocator_arg = allocator_arg_t();
bad_weak_ptr::~bad_weak_ptr() _NOEXCEPT {}
@@ -53,27 +31,27 @@
{
}
+__shared_weak_count::~__shared_weak_count()
+{
+}
+
void
__shared_count::__add_shared() _NOEXCEPT
{
- increment(__shared_owners_);
+ __libcpp_atomic_increment(__shared_owners_);
}
bool
__shared_count::__release_shared() _NOEXCEPT
{
- if (decrement(__shared_owners_) == -1)
+ if (__libcpp_atomic_decrement(__shared_owners_) == -1)
{
__on_zero_shared();
return true;
}
return false;
}
-__shared_weak_count::~__shared_weak_count()
-{
-}
-
void
__shared_weak_count::__add_shared() _NOEXCEPT
{
@@ -83,7 +61,7 @@
void
__shared_weak_count::__add_weak() _NOEXCEPT
{
- increment(__shared_weak_owners_);
+ __libcpp_atomic_increment(__shared_weak_owners_);
}
void
@@ -124,7 +102,7 @@
//__libcpp_atomic_store(&__shared_weak_owners_, -1, _AO_Release);
__on_zero_shared_weak();
}
- else if (decrement(__shared_weak_owners_) == -1)
+ else if (__libcpp_atomic_decrement(__shared_weak_owners_) == -1)
__on_zero_shared_weak();
}
Index: libcxx/include/memory
===================================================================
--- libcxx/include/memory
+++ libcxx/include/memory
@@ -3681,6 +3681,44 @@
#endif // _LIBCPP_STD_VER > 14
+// NOTE: Relaxed and acq/rel atomics (for increment and decrement respectively)
+// should be sufficient for thread safety.
+// See https://llvm.org/bugs/show_bug.cgi?id=22803
+#if defined(__clang__) && __has_builtin(__atomic_load_n) \
+ && __has_builtin(__atomic_store_n) \
+ && __has_builtin(__atomic_add_fetch) \
+ && __has_builtin(__atomic_compare_exchange_n) \
+ && defined(__ATOMIC_RELAXED) \
+ && defined(__ATOMIC_CONSUME) \
+ && defined(__ATOMIC_ACQUIRE) \
+ && defined(__ATOMIC_RELEASE) \
+ && defined(__ATOMIC_ACQ_REL) \
+ && defined(__ATOMIC_SEQ_CST)
+# define _LIBCPP_HAS_ATOMIC_BUILTINS
+#endif
+
+template <class T>
+inline T
+__libcpp_atomic_increment(T& t) _NOEXCEPT
+{
+#if defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
+ return __atomic_add_fetch(&t, 1, __ATOMIC_RELAXED);
+#else
+ return t += 1;
+#endif
+}
+
+template <class T>
+inline T
+__libcpp_atomic_decrement(T& t) _NOEXCEPT
+{
+#if defined(_LIBCPP_HAS_ATOMIC_BUILTINS) && !defined(_LIBCPP_HAS_NO_THREADS)
+ return __atomic_add_fetch(&t, -1, __ATOMIC_ACQ_REL);
+#else
+ return t -= 1;
+#endif
+}
+
class _LIBCPP_EXCEPTION_ABI bad_weak_ptr
: public std::exception
{
@@ -3717,8 +3755,23 @@
explicit __shared_count(long __refs = 0) _NOEXCEPT
: __shared_owners_(__refs) {}
- void __add_shared() _NOEXCEPT;
- bool __release_shared() _NOEXCEPT;
+#ifdef _LIBCPP_BUILDING_MEMORY
+ void _LIBCPP_FUNC_VIS __add_shared() _NOEXCEPT;
+ bool _LIBCPP_FUNC_VIS __release_shared() _NOEXCEPT;
+#else
+ inline _LIBCPP_INLINE_VISIBILITY
+ void __add_shared() _NOEXCEPT {
+ __libcpp_atomic_increment(__shared_owners_);
+ }
+ inline _LIBCPP_INLINE_VISIBILITY
+ bool __release_shared() _NOEXCEPT {
+ if (__libcpp_atomic_decrement(__shared_owners_) == -1) {
+ __on_zero_shared();
+ return true;
+ }
+ return false;
+ }
+#endif
_LIBCPP_INLINE_VISIBILITY
long use_count() const _NOEXCEPT {
return __libcpp_relaxed_load(&__shared_owners_) + 1;
@@ -3739,9 +3792,25 @@
virtual ~__shared_weak_count();
public:
- void __add_shared() _NOEXCEPT;
- void __add_weak() _NOEXCEPT;
- void __release_shared() _NOEXCEPT;
+#ifdef _LIBCPP_BUILDING_MEMORY
+ void _LIBCPP_FUNC_VIS __add_shared() _NOEXCEPT;
+ void _LIBCPP_FUNC_VIS __add_weak() _NOEXCEPT;
+ void _LIBCPP_FUNC_VIS __release_shared() _NOEXCEPT;
+#else
+ _LIBCPP_INLINE_VISIBILITY
+ void __add_shared() _NOEXCEPT {
+ __shared_count::__add_shared();
+ }
+ _LIBCPP_INLINE_VISIBILITY
+ void __add_weak() _NOEXCEPT {
+ __libcpp_atomic_increment(__shared_weak_owners_);
+ }
+ _LIBCPP_INLINE_VISIBILITY
+ void __release_shared() _NOEXCEPT {
+ if (__shared_count::__release_shared())
+ __release_weak();
+ }
+#endif
void __release_weak() _NOEXCEPT;
_LIBCPP_INLINE_VISIBILITY
long use_count() const _NOEXCEPT {return __shared_count::use_count();}
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