diff options
Diffstat (limited to 'gfx/cairo/support-new-style-atomic-primitives.patch')
| -rw-r--r-- | gfx/cairo/support-new-style-atomic-primitives.patch | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/gfx/cairo/support-new-style-atomic-primitives.patch b/gfx/cairo/support-new-style-atomic-primitives.patch new file mode 100644 index 0000000000..1830a4691f --- /dev/null +++ b/gfx/cairo/support-new-style-atomic-primitives.patch @@ -0,0 +1,121 @@ +From 5d150ee111c222f09e78f4f88540964476327844 Mon Sep 17 00:00:00 2001 +From: Nathan Froyd <froydnj@mozilla.com> +Date: Mon, 4 May 2015 13:38:41 -0400 +Subject: Support new-style __atomic_* primitives + +Recent versions of GCC/clang feature a new set of compiler intrinsics +for performing atomic operations, motivated by the operations needed to +support the C++11 memory model. These intrinsics are more flexible than +the old __sync_* intrinstics and offer efficient support for atomic load +and store operations. + +Having the load appear atomic to the compiler is particular important +for tools like ThreadSanitizer so they don't report false positives on +memory operations that we intend to be atomic. + +Patch from Nathan Froyd <froydnj@mozilla.com> + +diff --git a/src/cairo-atomic-private.h b/src/cairo-atomic-private.h +index 327fed1..11b2887 100644 +--- a/src/cairo-atomic-private.h ++++ b/src/cairo-atomic-private.h +@@ -53,6 +53,96 @@ + + CAIRO_BEGIN_DECLS + ++/* C++11 atomic primitives were designed to be more flexible than the ++ * __sync_* family of primitives. Despite the name, they are available ++ * in C as well as C++. The motivating reason for using them is that ++ * for _cairo_atomic_{int,ptr}_get, the compiler is able to see that ++ * the load is intended to be atomic, as opposed to the __sync_* ++ * version, below, where the load looks like a plain load. Having ++ * the load appear atomic to the compiler is particular important for ++ * tools like ThreadSanitizer so they don't report false positives on ++ * memory operations that we intend to be atomic. ++ */ ++#if HAVE_CXX11_ATOMIC_PRIMITIVES ++ ++#define HAS_ATOMIC_OPS 1 ++ ++typedef int cairo_atomic_int_t; ++ ++static cairo_always_inline cairo_atomic_int_t ++_cairo_atomic_int_get (cairo_atomic_int_t *x) ++{ ++ return __atomic_load_n(x, __ATOMIC_SEQ_CST); ++} ++ ++static cairo_always_inline void * ++_cairo_atomic_ptr_get (void **x) ++{ ++ return __atomic_load_n(x, __ATOMIC_SEQ_CST); ++} ++ ++# define _cairo_atomic_int_inc(x) ((void) __atomic_fetch_add(x, 1, __ATOMIC_SEQ_CST)) ++# define _cairo_atomic_int_dec(x) ((void) __atomic_fetch_sub(x, 1, __ATOMIC_SEQ_CST)) ++# define _cairo_atomic_int_dec_and_test(x) (__atomic_fetch_sub(x, 1, __ATOMIC_SEQ_CST) == 1) ++ ++#if SIZEOF_VOID_P==SIZEOF_INT ++typedef int cairo_atomic_intptr_t; ++#elif SIZEOF_VOID_P==SIZEOF_LONG ++typedef long cairo_atomic_intptr_t; ++#elif SIZEOF_VOID_P==SIZEOF_LONG_LONG ++typedef long long cairo_atomic_intptr_t; ++#else ++#error No matching integer pointer type ++#endif ++ ++static cairo_always_inline cairo_bool_t ++_cairo_atomic_int_cmpxchg_impl(cairo_atomic_int_t *x, ++ cairo_atomic_int_t oldv, ++ cairo_atomic_int_t newv) ++{ ++ cairo_atomic_int_t expected = oldv; ++ return __atomic_compare_exchange_n(x, &expected, newv, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); ++} ++ ++#define _cairo_atomic_int_cmpxchg(x, oldv, newv) \ ++ _cairo_atomic_int_cmpxchg_impl(x, oldv, newv) ++ ++static cairo_always_inline cairo_atomic_int_t ++_cairo_atomic_int_cmpxchg_return_old_impl(cairo_atomic_int_t *x, ++ cairo_atomic_int_t oldv, ++ cairo_atomic_int_t newv) ++{ ++ cairo_atomic_int_t expected = oldv; ++ (void) __atomic_compare_exchange_n(x, &expected, newv, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); ++ return expected; ++} ++ ++#define _cairo_atomic_int_cmpxchg_return_old(x, oldv, newv) \ ++ _cairo_atomic_int_cmpxchg_return_old_impl(x, oldv, newv) ++ ++static cairo_always_inline cairo_bool_t ++_cairo_atomic_ptr_cmpxchg_impl(void **x, void *oldv, void *newv) ++{ ++ void *expected = oldv; ++ return __atomic_compare_exchange_n(x, &expected, newv, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); ++} ++ ++#define _cairo_atomic_ptr_cmpxchg(x, oldv, newv) \ ++ _cairo_atomic_ptr_cmpxchg_impl(x, oldv, newv) ++ ++static cairo_always_inline void * ++_cairo_atomic_ptr_cmpxchg_return_old_impl(void **x, void *oldv, void *newv) ++{ ++ void *expected = oldv; ++ (void) __atomic_compare_exchange_n(x, &expected, newv, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); ++ return expected; ++} ++ ++#define _cairo_atomic_ptr_cmpxchg_return_old(x, oldv, newv) \ ++ _cairo_atomic_ptr_cmpxchg_return_old_impl(x, oldv, newv) ++ ++#endif ++ + #if HAVE_INTEL_ATOMIC_PRIMITIVES + + #define HAS_ATOMIC_OPS 1 +-- +cgit v0.10.2 + |