Contribution of PowerPC port (continuation of 422063005)

src/base/atomicops_internals_ppc_gcc.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is an internal atomic implementation, use atomicops.h instead.
+//
 
-#ifndef V8_BASE_ATOMICOPS_INTERNALS_PORTABLE_H_
-#define V8_BASE_ATOMICOPS_INTERNALS_PORTABLE_H_
+#ifndef V8_BASE_ATOMICOPS_INTERNALS_PPC_H_
+#define V8_BASE_ATOMICOPS_INTERNALS_PPC_H_
 
 namespace v8 {
 namespace base {
 
-inline void MemoryBarrier() { __sync_synchronize(); }
-
 inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
                                          Atomic32 old_value,
                                          Atomic32 new_value) {
-  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  return (__sync_val_compare_and_swap(ptr, old_value, new_value));
 }
 
 inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
                                          Atomic32 new_value) {
-  return __sync_lock_test_and_set(ptr, new_value);
+  Atomic32 old_value;
+  do {
+    old_value = *ptr;
+  } while (__sync_bool_compare_and_swap(ptr, old_value, new_value) == false);
+  return old_value;
 }
 
 inline Atomic32 NoBarrier_AtomicIncrement(volatile Atomic32* ptr,
                                           Atomic32 increment) {
-  return __sync_add_and_fetch(ptr, increment);
+  return Barrier_AtomicIncrement(ptr, increment);
 }
 
 inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
                                         Atomic32 increment) {
-  return __sync_add_and_fetch(ptr, increment);
+  for (;;) {
+    Atomic32 old_value = *ptr;
+    Atomic32 new_value = old_value + increment;
+    if (__sync_bool_compare_and_swap(ptr, old_value, new_value)) {
+      return new_value;
+      // The exchange took place as expected.
+    }
+    // Otherwise, *ptr changed mid-loop and we need to retry.
+  }
 }
 
 inline Atomic32 Acquire_CompareAndSwap(volatile Atomic32* ptr,
                                        Atomic32 old_value, Atomic32 new_value) {
-  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
                                        Atomic32 old_value, Atomic32 new_value) {
-  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
-  __sync_lock_test_and_set(ptr, value);
+  *ptr = value;
 }
 
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
-  __sync_lock_test_and_set(ptr, value);
+  *ptr = value;
 }
 
+inline void MemoryBarrier() {
+  __asm__ __volatile__("sync" : : : "memory"); }
+
 inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
-  __sync_lock_test_and_set(ptr, value);
+  *ptr = value;
+  MemoryBarrier();
 }
 
 inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
-  __sync_lock_test_and_set(ptr, value);
+  MemoryBarrier();
+  *ptr = value;
 }
 
-inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
-}
+inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) { return *ptr; }
 
-inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
-}
+inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) { return *ptr; }
 
 inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
+  Atomic32 value = *ptr;
+  MemoryBarrier();
+  return value;
 }
 
 inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
+  MemoryBarrier();
+  return *ptr;
 }
 
-// 64-bit versions of the operations.
-// See the 32-bit versions for comments.
-
+#ifdef V8_TARGET_ARCH_PPC64
 inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
                                          Atomic64 old_value,
                                          Atomic64 new_value) {
-  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  return (__sync_val_compare_and_swap(ptr, old_value, new_value));
 }
 
 inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
                                          Atomic64 new_value) {
-  return __sync_lock_test_and_set(ptr, new_value);
+  Atomic64 old_value;
+  do {
+    old_value = *ptr;
+  } while (__sync_bool_compare_and_swap(ptr, old_value, new_value) == false);
+  return old_value;
 }
 
 inline Atomic64 NoBarrier_AtomicIncrement(volatile Atomic64* ptr,
                                           Atomic64 increment) {
-  return __sync_add_and_fetch(ptr, increment);
+  return Barrier_AtomicIncrement(ptr, increment);
 }
 
 inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
                                         Atomic64 increment) {
-  return __sync_add_and_fetch(ptr, increment);
+  for (;;) {
+    Atomic64 old_value = *ptr;
+    Atomic64 new_value = old_value + increment;
+    if (__sync_bool_compare_and_swap(ptr, old_value, new_value)) {
+      return new_value;
+      // The exchange took place as expected.
+    }
+    // Otherwise, *ptr changed mid-loop and we need to retry.
+  }
 }
 
 inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
                                        Atomic64 old_value, Atomic64 new_value) {
-  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
                                        Atomic64 old_value, Atomic64 new_value) {
-  return __sync_val_compare_and_swap(ptr, old_value, new_value);
+  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
-  __sync_lock_test_and_set(ptr, value);
+  *ptr = value;
 }
 
 inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
-  __sync_lock_test_and_set(ptr, value);
+  *ptr = value;
+  MemoryBarrier();
 }
 
 inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
-  __sync_lock_test_and_set(ptr, value);
+  MemoryBarrier();
+  *ptr = value;
 }
 
-inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
-}
+inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) { return *ptr; }
 
 inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
+  Atomic64 value = *ptr;
+  MemoryBarrier();
+  return value;
 }
 
 inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
-  return __sync_add_and_fetch(ptr, 0);
+  MemoryBarrier();
+  return *ptr;
 }
+
+#endif
 }
 }  // namespace v8::base
 
-#endif  // V8_BASE_ATOMICOPS_INTERNALS_PORTABLE_H_
+#endif  // V8_BASE_ATOMICOPS_INTERNALS_PPC_GCC_H_