Fix broken android framework builds where 32-bit MIPS compilers lack 64-bit __sync operators.

src/ports/SkAtomics_mips32.h

 /*
- * Copyright 2013 Google Inc.
+ * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
-#ifndef SkAtomics_sync_DEFINED
-#define SkAtomics_sync_DEFINED
+#ifndef SkAtomics_mips32_DEFINED
+#define SkAtomics_mips32_DEFINED
 
-/** GCC/Clang __sync based atomics. */
+/** Similar to SkAtomics_sync but the 32-bit MIPS toolchains for the android
+ *  framework are missing support for __sync* functions that operate on 64-bit
+ *  values. Instead these functions uses __atomic to work around those specific

[scroggo, 2014/07/16 19:16:25]

use*

+ *  issues until we can move to <stdatomic.h>.
+ */
 
 #include <stdint.h>
 
 static inline __attribute__((always_inline)) int32_t sk_atomic_inc(int32_t* addr) {
     return __sync_fetch_and_add(addr, 1);
 }
 
 static inline __attribute__((always_inline)) int64_t sk_atomic_inc(int64_t* addr) {
-    return __sync_fetch_and_add(addr, 1);
+    return __atomic_fetch_add(addr, 1, __ATOMIC_SEQ_CST);
 }
 
 static inline __attribute__((always_inline)) int32_t sk_atomic_add(int32_t* addr, int32_t inc) {
     return __sync_fetch_and_add(addr, inc);
 }
 
 static inline __attribute__((always_inline)) int64_t sk_atomic_add(int64_t* addr, int64_t inc) {
     return __sync_fetch_and_add(addr, inc);
 }
 
 static inline __attribute__((always_inline)) int32_t sk_atomic_dec(int32_t* addr) {
     return __sync_fetch_and_add(addr, -1);
 }
 
 static inline __attribute__((always_inline)) int64_t sk_atomic_dec(int64_t* addr) {
-    return __sync_fetch_and_add(addr, -1);
+    return __atomic_fetch_add(addr, -1, __ATOMIC_SEQ_CST);
 }
 
 static inline __attribute__((always_inline)) void sk_membar_acquire__after_atomic_dec() { }
 
 static inline __attribute__((always_inline)) bool sk_atomic_cas(int32_t* addr,
                                                                 int32_t before,
                                                                 int32_t after) {
     return __sync_bool_compare_and_swap(addr, before, after);
 }
 
 static inline __attribute__((always_inline)) bool sk_atomic_cas(int64_t* addr,
                                                                 int64_t before,
                                                                 int64_t after) {
-    return __sync_bool_compare_and_swap(addr, before, after);
+    return __atomic_compare_exchange_n(addr, &before, after,
+                                       false /*strong*/,
+                                       __ATOMIC_SEQ_CST /*on success*/,
+                                       __ATOMIC_SEQ_CST /*on failure*/);
 }
 
 static inline __attribute__((always_inline)) void* sk_atomic_cas(void** addr,
                                                                  void* before,
                                                                  void* after) {
     return __sync_val_compare_and_swap(addr, before, after);
 }
 
 static inline __attribute__((always_inline)) void sk_membar_acquire__after_atomic_conditional_inc() { }
 
 #endif