Attachment 115535 Details for Bug 90303 – patch

[patch] patch

cairo-atomics.patch (text/plain), 5.10 KB, created by Nathan Froyd on 2015-05-04 17:58:05 UTC

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Creator: Nathan Froyd

Created: 2015-05-04 17:58:05 UTC

Size: 5.10 KB

patch

obsolete

>commit af384636e9c86a41f398e9913e6363a7549bdcd6
>Author: Nathan Froyd <froydnj@mozilla.com>
>Date:   Mon May 4 13:38:41 2015 -0400
>
>    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.
>
>diff --git a/build/aclocal.cairo.m4 b/build/aclocal.cairo.m4
>index 2f4873b..44ba5fd 100644
>--- a/build/aclocal.cairo.m4
>+++ b/build/aclocal.cairo.m4
>@@ -168,6 +168,13 @@ int atomic_cmpxchg(int i, int j, int k) { return __sync_val_compare_and_swap (&i
> 		  cairo_cv_atomic_primitives="Intel"
> 		  )
> 
>+		AC_TRY_LINK([
>+int atomic_add(int i) { return __atomic_fetch_add(&i, 1, __ATOMIC_SEQ_CST); }
>+int atomic_cmpxchg(int i, int j, int k) { return __atomic_compare_exchange_n(&i, &j, k, 0, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); }
>+], [],
>+		   cairo_cv_atomic_primitives="cxx11"
>+		   )
>+
> 		if test "x$cairo_cv_atomic_primitives" = "xnone"; then
> 			AC_CHECK_HEADER([atomic_ops.h],
> 					cairo_cv_atomic_primitives="libatomic-ops")
>@@ -178,6 +185,11 @@ int atomic_cmpxchg(int i, int j, int k) { return __sync_val_compare_and_swap (&i
> 					cairo_cv_atomic_primitives="OSAtomic")
> 		fi
> 	])
>+	if test "x$cairo_cv_atomic_primitives" = xcxx11; then
>+		AC_DEFINE(HAVE_CXX11_ATOMIC_PRIMITIVES, 1,
>+			  [Enable if your compiler supports the GCC __atomic_* atomic primitives])
>+	fi
>+
> 	if test "x$cairo_cv_atomic_primitives" = xIntel; then
> 		AC_DEFINE(HAVE_INTEL_ATOMIC_PRIMITIVES, 1,
> 			  [Enable if your compiler supports the Intel __sync_* atomic primitives])
>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

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