Contribution of PowerPC port.

src/base/atomicops_internals_ppc_gcc.h

 // Copyright 2010 the V8 project authors. All rights reserved.

[danno, 2014/07/29 13:24:07]

Please use the new compact header.

[andrew_low, 2014/07/30 13:27:04]

Acknowledged.

-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // This file is an internal atomic implementation, use atomicops.h instead.
+//
 
-#ifndef V8_BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
-#define V8_BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
-
-#include "src/base/macros.h"
-#include "src/base/win32-headers.h"
-
-#if defined(V8_HOST_ARCH_64_BIT)
-// windows.h #defines this (only on x64). This causes problems because the
-// public API also uses MemoryBarrier at the public name for this fence. So, on
-// X64, undef it, and call its documented
-// (http://msdn.microsoft.com/en-us/library/windows/desktop/ms684208.aspx)
-// implementation directly.
-#undef MemoryBarrier
-#endif
+#ifndef V8_BASE_ATOMICOPS_INTERNALS_PPC_H_
+#define V8_BASE_ATOMICOPS_INTERNALS_PPC_H_
 
 namespace v8 {
 namespace base {
 
 inline Atomic32 NoBarrier_CompareAndSwap(volatile Atomic32* ptr,
                                          Atomic32 old_value,
                                          Atomic32 new_value) {
-  LONG result = InterlockedCompareExchange(
-      reinterpret_cast<volatile LONG*>(ptr),
-      static_cast<LONG>(new_value),
-      static_cast<LONG>(old_value));
-  return static_cast<Atomic32>(result);
+  return(__sync_val_compare_and_swap( ptr, old_value, new_value));
 }
 
 inline Atomic32 NoBarrier_AtomicExchange(volatile Atomic32* ptr,
                                          Atomic32 new_value) {
-  LONG result = InterlockedExchange(
-      reinterpret_cast<volatile LONG*>(ptr),
-      static_cast<LONG>(new_value));
-  return static_cast<Atomic32>(result);
-}
-
-inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
-                                        Atomic32 increment) {
-  return InterlockedExchangeAdd(
-      reinterpret_cast<volatile LONG*>(ptr),
-      static_cast<LONG>(increment)) + increment;
+  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 Barrier_AtomicIncrement(ptr, increment);
 }
 
-#if !(defined(_MSC_VER) && _MSC_VER >= 1400)
-#error "We require at least vs2005 for MemoryBarrier"
-#endif
-inline void MemoryBarrier() {
-#if defined(V8_HOST_ARCH_64_BIT)
-  // See #undef and note at the top of this file.
-  __faststorefence();
-#else
-  // We use MemoryBarrier from WinNT.h
-  ::MemoryBarrier();
-#endif
+inline Atomic32 Barrier_AtomicIncrement(volatile Atomic32* ptr,
+                                        Atomic32 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 NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline Atomic32 Release_CompareAndSwap(volatile Atomic32* ptr,
                                        Atomic32 old_value,
                                        Atomic32 new_value) {
   return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
 }
 
 inline void NoBarrier_Store(volatile Atomic8* ptr, Atomic8 value) {
   *ptr = value;
 }
 
 inline void NoBarrier_Store(volatile Atomic32* ptr, Atomic32 value) {
   *ptr = value;
 }
 
+inline void MemoryBarrier() {
+  __asm__ __volatile__("sync" : : : "memory");
+}
+
 inline void Acquire_Store(volatile Atomic32* ptr, Atomic32 value) {
-  NoBarrier_AtomicExchange(ptr, value);
-              // acts as a barrier in this implementation
+  *ptr = value;
+  MemoryBarrier();
 }
 
 inline void Release_Store(volatile Atomic32* ptr, Atomic32 value) {
-  *ptr = value;  // works w/o barrier for current Intel chips as of June 2005
-  // See comments in Atomic64 version of Release_Store() below.
+  MemoryBarrier();
+  *ptr = value;
 }
 
 inline Atomic8 NoBarrier_Load(volatile const Atomic8* ptr) {
   return *ptr;
 }
 
 inline Atomic32 NoBarrier_Load(volatile const Atomic32* ptr) {
   return *ptr;
 }
 
 inline Atomic32 Acquire_Load(volatile const Atomic32* ptr) {
   Atomic32 value = *ptr;
+  MemoryBarrier();
   return value;
 }
 
 inline Atomic32 Release_Load(volatile const Atomic32* ptr) {
   MemoryBarrier();
   return *ptr;
 }
 
-#if defined(_WIN64)
-
-// 64-bit low-level operations on 64-bit platform.
-
-STATIC_ASSERT(sizeof(Atomic64) == sizeof(PVOID));
-
+#ifdef V8_TARGET_ARCH_PPC64
 inline Atomic64 NoBarrier_CompareAndSwap(volatile Atomic64* ptr,
                                          Atomic64 old_value,
                                          Atomic64 new_value) {
-  PVOID result = InterlockedCompareExchangePointer(
-    reinterpret_cast<volatile PVOID*>(ptr),
-    reinterpret_cast<PVOID>(new_value), reinterpret_cast<PVOID>(old_value));
-  return reinterpret_cast<Atomic64>(result);
+  return(__sync_val_compare_and_swap( ptr, old_value, new_value));
 }
 
 inline Atomic64 NoBarrier_AtomicExchange(volatile Atomic64* ptr,
                                          Atomic64 new_value) {
-  PVOID result = InterlockedExchangePointer(
-    reinterpret_cast<volatile PVOID*>(ptr),
-    reinterpret_cast<PVOID>(new_value));
-  return reinterpret_cast<Atomic64>(result);
-}
-
-inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
-                                        Atomic64 increment) {
-  return InterlockedExchangeAdd64(
-      reinterpret_cast<volatile LONGLONG*>(ptr),
-      static_cast<LONGLONG>(increment)) + increment;
+  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 Barrier_AtomicIncrement(ptr, increment);
 }
 
+inline Atomic64 Barrier_AtomicIncrement(volatile Atomic64* ptr,
+                                        Atomic64 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 NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+}
+
+inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
+                                       Atomic64 old_value,
+                                       Atomic64 new_value) {
+  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
+}
+
 inline void NoBarrier_Store(volatile Atomic64* ptr, Atomic64 value) {
   *ptr = value;
 }
 
 inline void Acquire_Store(volatile Atomic64* ptr, Atomic64 value) {
-  NoBarrier_AtomicExchange(ptr, value);
-              // acts as a barrier in this implementation
+  *ptr = value;
+  MemoryBarrier();
 }
 
 inline void Release_Store(volatile Atomic64* ptr, Atomic64 value) {
-  *ptr = value;  // works w/o barrier for current Intel chips as of June 2005
-
-  // When new chips come out, check:
-  //  IA-32 Intel Architecture Software Developer's Manual, Volume 3:
-  //  System Programming Guide, Chatper 7: Multiple-processor management,
-  //  Section 7.2, Memory Ordering.
-  // Last seen at:
-  //   http://developer.intel.com/design/pentium4/manuals/index_new.htm
+  MemoryBarrier();
+  *ptr = value;
 }
 
 inline Atomic64 NoBarrier_Load(volatile const Atomic64* ptr) {
   return *ptr;
 }
 
 inline Atomic64 Acquire_Load(volatile const Atomic64* ptr) {
   Atomic64 value = *ptr;
+  MemoryBarrier();
   return value;
 }
 
 inline Atomic64 Release_Load(volatile const Atomic64* ptr) {
   MemoryBarrier();
   return *ptr;
 }
 
-inline Atomic64 Acquire_CompareAndSwap(volatile Atomic64* ptr,
-                                       Atomic64 old_value,
-                                       Atomic64 new_value) {
-  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
-}
-
-inline Atomic64 Release_CompareAndSwap(volatile Atomic64* ptr,
-                                       Atomic64 old_value,
-                                       Atomic64 new_value) {
-  return NoBarrier_CompareAndSwap(ptr, old_value, new_value);
-}
-
-
-#endif  // defined(_WIN64)
+#endif
 
 } }  // namespace v8::base
 
-#endif  // V8_BASE_ATOMICOPS_INTERNALS_X86_MSVC_H_
+#endif  // V8_BASE_ATOMICOPS_INTERNALS_PPC_GCC_H_