From 04bc1eebe7a304c0e6f86ab6814c65889f152602 Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Tue, 5 Jun 2012 20:16:56 -0400
Subject: [PATCH] Add configure tests for Intel atomic intrinsics

---
 configure.ac             | 17 +++++++++++++++++
 src/hb-atomic-private.hh | 12 ++++++------
 src/hb-mutex-private.hh  |  2 +-
 3 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/configure.ac b/configure.ac
index d126b16..2fb058f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -177,6 +177,23 @@ if $have_uniscribe; then
 fi
 AM_CONDITIONAL(HAVE_UNISCRIBE, $have_uniscribe)
 
+dnl ===========================================================================
+
+AC_CACHE_CHECK([for Intel atomic primitives], hb_cv_have_intel_atomic_primitives, [
+	hb_cv_have_intel_atomic_primitives=false
+	AC_TRY_LINK([], [
+		void memory_barrier (void) { __sync_synchronize (); }
+		int atomic_add (int i) { return __sync_fetch_and_add (&i, 1); }
+		int atomic_cmpxchg (int *i, int *j, int *k) { return __sync_bool_compare_and_swap (&i, j, k); }
+		], hb_cv_have_intel_atomic_primitives=true
+	)
+])
+if $hb_cv_have_intel_atomic_primitives; then
+	AC_DEFINE(HAVE_INTEL_ATOMIC_PRIMITIVES, 1, [Have Intel __sync_* atomic primitives])
+fi
+
+dnl ===========================================================================
+
 AC_CONFIG_FILES([
 Makefile
 harfbuzz.pc
diff --git a/src/hb-atomic-private.hh b/src/hb-atomic-private.hh
index c1b25bd..0e7ecae 100644
--- a/src/hb-atomic-private.hh
+++ b/src/hb-atomic-private.hh
@@ -51,7 +51,7 @@ typedef long hb_atomic_int_t;
 #define hb_atomic_int_add(AI, V)	_InterlockedExchangeAdd (&(AI), (V))
 
 #define hb_atomic_ptr_get(P)		(MemoryBarrier (), (void *) *(P))
-#define hb_atomic_ptr_cmpexch(P,O,N)	(_InterlockedCompareExchangePointer ((void * volatile *) (P), (N), (O)) == (O))
+#define hb_atomic_ptr_cmpexch(P,O,N)	(_InterlockedCompareExchangePointer ((void **) (P), (void *) (N), (void *) (O)) == (void *) (O))
 
 
 #elif !defined(HB_NO_MT) && defined(__APPLE__)
@@ -62,10 +62,10 @@ typedef int32_t hb_atomic_int_t;
 #define hb_atomic_int_add(AI, V)	(OSAtomicAdd32Barrier ((V), &(AI)) - (V))
 
 #define hb_atomic_ptr_get(P)		(OSMemoryBarrier (), (void *) *(P))
-#define hb_atomic_ptr_cmpexch(P,O,N)	OSAtomicCompareAndSwapPtrBarrier ((O), (N), (void * volatile *) (P))
+#define hb_atomic_ptr_cmpexch(P,O,N)	OSAtomicCompareAndSwapPtrBarrier ((void *) (O), (void *) (N), (void **) (P))
 
 
-#elif !defined(HB_NO_MT) && defined(__GNUC__)
+#elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)
 
 typedef int hb_atomic_int_t;
 #define hb_atomic_int_add(AI, V)	__sync_fetch_and_add (&(AI), (V))
@@ -84,7 +84,7 @@ typedef int hb_atomic_int_t;
 #endif
 
 #define hb_atomic_ptr_get(P)		g_atomic_pointer_get (P)
-#define hb_atomic_ptr_cmpexch(P,O,N)	g_atomic_pointer_compare_and_exchange ((void * volatile *) (P), (O), (N))
+#define hb_atomic_ptr_cmpexch(P,O,N)	g_atomic_pointer_compare_and_exchange ((void **) (P), (void *) (O), (void *) (N))
 
 
 #elif !defined(HB_NO_MT)
@@ -94,7 +94,7 @@ typedef volatile int hb_atomic_int_t;
 #define hb_atomic_int_add(AI, V)	(((AI) += (V)) - (V))
 
 #define hb_atomic_ptr_get(P)		((void *) *(P))
-#define hb_atomic_ptr_cmpexch(P,O,N)	(*(P) == (O) ? (*(P) = (N), TRUE) : FALSE)
+#define hb_atomic_ptr_cmpexch(P,O,N)	(* (void * volatile *) (P) == (void *) (O) ? (* (void * volatile *) (P) = (void *) (N), TRUE) : FALSE)
 
 
 #else /* HB_NO_MT */
@@ -103,7 +103,7 @@ typedef int hb_atomic_int_t;
 #define hb_atomic_int_add(AI, V)	(((AI) += (V)) - (V))
 
 #define hb_atomic_ptr_get(P)		((void *) *(P))
-#define hb_atomic_ptr_cmpexch(P,O,N)	*(P)
+#define hb_atomic_ptr_cmpexch(P,O,N)	(* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), TRUE) : FALSE)
 
 #endif
 
diff --git a/src/hb-mutex-private.hh b/src/hb-mutex-private.hh
index 9278643..a6d16e9 100644
--- a/src/hb-mutex-private.hh
+++ b/src/hb-mutex-private.hh
@@ -75,7 +75,7 @@ typedef GStaticMutex hb_mutex_impl_t;
 #define hb_mutex_impl_finish(M)	g_static_mutex_free (M)
 
 
-#elif !defined(HB_NO_MT) && defined(__GNUC__)
+#elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)
 
 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
 # include <sched.h>
-- 
2.7.4