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gatomic: Use new __atomic_*() intrinsics for all atomic operations

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Previously we used the old `__sync_fetch_*()` intrinsics for some of the
atomic operations, such as `g_atomic_int_compare_and_exchange()`. When
available, use the new `__atomic_*()` intrinsics for those instead.

As with the rest of our use of `__atomic_*()` intrinsics, we use the
`__ATOMIC_SEQ_CST` memory model. If people want to use a less
restrictive memory model to get better performance in certain
situations, they can use the compiler intrinsics directly themselves.
`g_atomic_*()` aim to be as fast as possible while remaining general
purpose.

Tested using:
```
meson test --repeat 1000 atomic atomic-test
```

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Fixes: #1750
This commit is contained in:
Philip Withnall 2019-09-21 17:34:37 +02:00
parent 02a7af780b
commit 2eb3762241
1 changed files with 88 additions and 2 deletions
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90
glib/gatomic.h
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@ -118,6 +118,92 @@ G_END_DECLS
__atomic_store ((gpointer *)(atomic), &gaps_temp, __ATOMIC_SEQ_CST); \
}))
#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_compare_and_exchange(atomic, oldval, newval) \
(G_GNUC_EXTENSION ({ \
__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; \
}))
#define g_atomic_pointer_add(atomic, val) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gpointer)); \
(void) (0 ? (gpointer) *(atomic) : NULL); \
(void) (0 ? (val) ^ (val) : 1); \
(gssize) __atomic_fetch_add ((atomic), (val), __ATOMIC_SEQ_CST); \
}))
#define g_atomic_pointer_and(atomic, val) \
(G_GNUC_EXTENSION ({ \
volatile gsize *gapa_atomic = (volatile 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 ({ \
volatile gsize *gapo_atomic = (volatile 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 ({ \
volatile gsize *gapx_atomic = (volatile 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); \
}))
#else /* defined(__ATOMIC_SEQ_CST) */
/* We want to achieve __ATOMIC_SEQ_CST semantics here. See
@ -184,8 +270,6 @@ G_END_DECLS
*(atomic) = (__typeof__ (*(atomic))) (gsize) (newval); \
}))
#endif /* !defined(__ATOMIC_SEQ_CST) */
#define g_atomic_int_inc(atomic) \
(G_GNUC_EXTENSION ({ \
G_STATIC_ASSERT (sizeof *(atomic) == sizeof (gint)); \
@ -264,6 +348,8 @@ G_END_DECLS
(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) \