#if defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
/* We prefer the new C11-style atomic extension of GCC if available */
-#if defined(__ATOMIC_SEQ_CST) && !defined(__clang__)
-
-/* This assumes sizeof(int) is 4: gatomic.c statically
- * asserts that (using G_STATIC_ASSERT at top-level in a header was
- * problematic, see #730932) */
+#if defined(__ATOMIC_SEQ_CST)
#define g_atomic_int_get(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ gint gaig_temp; \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
- (gint) __atomic_load_4 ((atomic), __ATOMIC_SEQ_CST); \
+ __atomic_load ((gint *)(atomic), &gaig_temp, __ATOMIC_SEQ_CST); \
+ (gint) gaig_temp; \
}))
#define g_atomic_int_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ gint gais_temp = (gint) (newval); \
(void) (0 ? *(atomic) ^ (newval) : 1); \
- __atomic_store_4 ((atomic), (newval), __ATOMIC_SEQ_CST); \
+ __atomic_store ((gint *)(atomic), &gais_temp, __ATOMIC_SEQ_CST); \
}))
-#if GLIB_SIZEOF_VOID_P == 8
-
+#if defined(glib_typeof)
+#define g_atomic_pointer_get(atomic) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ glib_typeof (*(atomic)) gapg_temp_newval; \
+ glib_typeof ((atomic)) gapg_temp_atomic = (atomic); \
+ __atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
+ gapg_temp_newval; \
+ }))
+#define g_atomic_pointer_set(atomic, newval) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ glib_typeof ((atomic)) gaps_temp_atomic = (atomic); \
+ glib_typeof (*(atomic)) gaps_temp_newval = (newval); \
+ (void) (0 ? (gpointer) * (atomic) : NULL); \
+ __atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST); \
+ }))
+#else /* if !defined(glib_typeof) */
#define g_atomic_pointer_get(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
- (gpointer) __atomic_load_8 ((atomic), __ATOMIC_SEQ_CST); \
+ gpointer gapg_temp_newval; \
+ gpointer *gapg_temp_atomic = (gpointer *)(atomic); \
+ __atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
+ gapg_temp_newval; \
}))
#define g_atomic_pointer_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ gpointer *gaps_temp_atomic = (gpointer *)(atomic); \
+ gpointer gaps_temp_newval = (gpointer)(newval); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
- __atomic_store_8 ((atomic), (gsize) (newval), __ATOMIC_SEQ_CST); \
+ __atomic_store (gaps_temp_atomic, &gaps_temp_newval, __ATOMIC_SEQ_CST); \
}))
+#endif /* !defined(glib_typeof) */
-#else /* GLIB_SIZEOF_VOID_P == 8 */
-
-/* This assumes that if sizeof(void *) is not 8, then it is 4:
- * gatomic.c statically asserts that (using G_STATIC_ASSERT
- * at top-level in a header was problematic, see #730932) */
+#define g_atomic_int_inc(atomic) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ *(atomic) : 1); \
+ (void) __atomic_fetch_add ((atomic), 1, __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_int_dec_and_test(atomic) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ *(atomic) : 1); \
+ __atomic_fetch_sub ((atomic), 1, __ATOMIC_SEQ_CST) == 1; \
+ }))
+#define g_atomic_int_compare_and_exchange(atomic, oldval, newval) \
+ (G_GNUC_EXTENSION ({ \
+ gint gaicae_oldval = (oldval); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ (newval) ^ (oldval) : 1); \
+ __atomic_compare_exchange_n ((atomic), &gaicae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
+ }))
+#define g_atomic_int_add(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ (val) : 1); \
+ (gint) __atomic_fetch_add ((atomic), (val), __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_int_and(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ (val) : 1); \
+ (guint) __atomic_fetch_and ((atomic), (val), __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_int_or(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ (val) : 1); \
+ (guint) __atomic_fetch_or ((atomic), (val), __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_int_xor(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
+ (void) (0 ? *(atomic) ^ (val) : 1); \
+ (guint) __atomic_fetch_xor ((atomic), (val), __ATOMIC_SEQ_CST); \
+ }))
-#define g_atomic_pointer_get(atomic) \
+#if defined(glib_typeof)
+#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer)); \
+ glib_typeof ((oldval)) gapcae_oldval = (oldval); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ (void) (0 ? (gpointer) *(atomic) : NULL); \
+ __atomic_compare_exchange_n ((atomic), &gapcae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
+ }))
+#else /* if !defined(glib_typeof) */
+#define g_atomic_pointer_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof (oldval) == sizeof (gpointer)); \
+ gpointer gapcae_oldval = (gpointer)(oldval); \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
- (gpointer) __atomic_load_4 ((atomic), __ATOMIC_SEQ_CST); \
+ (void) (0 ? (gpointer) *(atomic) : NULL); \
+ __atomic_compare_exchange_n ((atomic), &gapcae_oldval, (newval), FALSE, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ? TRUE : FALSE; \
}))
-#define g_atomic_pointer_set(atomic, newval) \
+#endif /* defined(glib_typeof) */
+#define g_atomic_pointer_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
- __atomic_store_4 ((atomic), (gsize) (newval), __ATOMIC_SEQ_CST); \
+ (void) (0 ? (val) ^ (val) : 1); \
+ (gssize) __atomic_fetch_add ((atomic), (val), __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_pointer_and(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ gsize *gapa_atomic = (gsize *) (atomic); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gsize)); \
+ (void) (0 ? (gpointer) *(atomic) : NULL); \
+ (void) (0 ? (val) ^ (val) : 1); \
+ (gsize) __atomic_fetch_and (gapa_atomic, (val), __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_pointer_or(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ gsize *gapo_atomic = (gsize *) (atomic); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gsize)); \
+ (void) (0 ? (gpointer) *(atomic) : NULL); \
+ (void) (0 ? (val) ^ (val) : 1); \
+ (gsize) __atomic_fetch_or (gapo_atomic, (val), __ATOMIC_SEQ_CST); \
+ }))
+#define g_atomic_pointer_xor(atomic, val) \
+ (G_GNUC_EXTENSION ({ \
+ gsize *gapx_atomic = (gsize *) (atomic); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gsize)); \
+ (void) (0 ? (gpointer) *(atomic) : NULL); \
+ (void) (0 ? (val) ^ (val) : 1); \
+ (gsize) __atomic_fetch_xor (gapx_atomic, (val), __ATOMIC_SEQ_CST); \
}))
-
-#endif /* GLIB_SIZEOF_VOID_P == 8 */
#else /* defined(__ATOMIC_SEQ_CST) */
+/* We want to achieve __ATOMIC_SEQ_CST semantics here. See
+ * https://en.cppreference.com/w/c/atomic/memory_order#Constants. For load
+ * operations, that means performing an *acquire*:
+ * > A load operation with this memory order performs the acquire operation on
+ * > the affected memory location: no reads or writes in the current thread can
+ * > be reordered before this load. All writes in other threads that release
+ * > the same atomic variable are visible in the current thread.
+ *
+ * “no reads or writes in the current thread can be reordered before this load”
+ * is implemented using a compiler barrier (a no-op `__asm__` section) to
+ * prevent instruction reordering. Writes in other threads are synchronised
+ * using `__sync_synchronize()`. It’s unclear from the GCC documentation whether
+ * `__sync_synchronize()` acts as a compiler barrier, hence our explicit use of
+ * one.
+ *
+ * For store operations, `__ATOMIC_SEQ_CST` means performing a *release*:
+ * > A store operation with this memory order performs the release operation:
+ * > no reads or writes in the current thread can be reordered after this store.
+ * > All writes in the current thread are visible in other threads that acquire
+ * > the same atomic variable (see Release-Acquire ordering below) and writes
+ * > that carry a dependency into the atomic variable become visible in other
+ * > threads that consume the same atomic (see Release-Consume ordering below).
+ *
+ * “no reads or writes in the current thread can be reordered after this store”
+ * is implemented using a compiler barrier to prevent instruction reordering.
+ * “All writes in the current thread are visible in other threads” is implemented
+ * using `__sync_synchronize()`; similarly for “writes that carry a dependency”.
+ */
#define g_atomic_int_get(atomic) \
(G_GNUC_EXTENSION ({ \
+ gint gaig_result; \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ *(atomic) : 1); \
+ gaig_result = (gint) *(atomic); \
__sync_synchronize (); \
- (gint) *(atomic); \
+ __asm__ __volatile__ ("" : : : "memory"); \
+ gaig_result; \
}))
#define g_atomic_int_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (newval) : 1); \
- *(atomic) = (newval); \
__sync_synchronize (); \
+ __asm__ __volatile__ ("" : : : "memory"); \
+ *(atomic) = (newval); \
}))
#define g_atomic_pointer_get(atomic) \
(G_GNUC_EXTENSION ({ \
+ gpointer gapg_result; \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ gapg_result = (gpointer) *(atomic); \
__sync_synchronize (); \
- (gpointer) *(atomic); \
+ __asm__ __volatile__ ("" : : : "memory"); \
+ gapg_result; \
}))
+#if defined(glib_typeof)
#define g_atomic_pointer_set(atomic, newval) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
- *(atomic) = (__typeof__ (*(atomic))) (gsize) (newval); \
__sync_synchronize (); \
+ __asm__ __volatile__ ("" : : : "memory"); \
+ *(atomic) = (glib_typeof (*(atomic))) (gsize) (newval); \
}))
-
-#endif /* !defined(__ATOMIC_SEQ_CST) */
+#else /* if !defined(glib_typeof) */
+#define g_atomic_pointer_set(atomic, newval) \
+ (G_GNUC_EXTENSION ({ \
+ G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
+ (void) (0 ? (gpointer) *(atomic) : NULL); \
+ __sync_synchronize (); \
+ __asm__ __volatile__ ("" : : : "memory"); \
+ *(atomic) = (gpointer) (gsize) (newval); \
+ }))
+#endif /* defined(glib_typeof) */
#define g_atomic_int_inc(atomic) \
(G_GNUC_EXTENSION ({ \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
(void) (0 ? *(atomic) ^ (newval) ^ (oldval) : 1); \
- (gboolean) __sync_bool_compare_and_swap ((atomic), (oldval), (newval)); \
+ __sync_bool_compare_and_swap ((atomic), (oldval), (newval)) ? TRUE : FALSE; \
}))
#define g_atomic_int_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
- (gboolean) __sync_bool_compare_and_swap ((atomic), (oldval), (newval)); \
+ __sync_bool_compare_and_swap ((atomic), (oldval), (newval)) ? TRUE : FALSE; \
}))
#define g_atomic_pointer_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
(gsize) __sync_fetch_and_xor ((atomic), (val)); \
}))
+#endif /* !defined(__ATOMIC_SEQ_CST) */
+
#else /* defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) */
#define g_atomic_int_get(atomic) \
#define g_atomic_pointer_xor(atomic, val) \
(g_atomic_pointer_xor ((atomic), (gsize) (val)))
-#endif /* defined(__GNUC__) && defined(G_ATOMIC_OP_USE_GCC_BUILTINS) */
+#endif /* defined(G_ATOMIC_LOCK_FREE) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) */
#endif /* __G_ATOMIC_H__ */
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