Add a write buffer, aligned so that a single bit tells us whether it has...

src/write-buffer.h

+// Copyright 2010 the V8 project authors. All rights reserved.
+// 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
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+//       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.
+//
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+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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+
+#ifndef V8_WRITE_BARRIER_H_
+#define V8_WRITE_BARRIER_H_
+
+#include "allocation.h"
+#include "checks.h"
+#include "globals.h"
+#include "platform.h"
+
+namespace v8 {
+namespace internal {
+
+class WriteBuffer : public AllStatic {

[Vyacheslav Egorov (Chromium), 2010/12/14 22:40:14]

Consider adding a small comment about the role of this class.

[Erik Corry, 2010/12/15 08:00:13]

Done.

+ public:
+  static Address Top() { return reinterpret_cast<Address>(&top_); }
+
+  static void Setup();
+  static void TearDown();
+
+  static const int kWriteBufferSize = 32 * KB;
+  static const int kWriteBufferOverflowBit = 1 << 15;

[Vyacheslav Egorov (Chromium), 2010/12/14 22:40:14]

15 and 32 are connected.

consider expressing this connection through introduction of a constant

[Erik Corry, 2010/12/15 08:00:13]

Done.

+
+ private:
+  static Address top_;
+  static Address start_;
+  static Address limit_;
+  static VirtualMemory* virtual_memory_;
+
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_WRITE_BARRIER_H_