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

src/write-buffer.h

Index: src/write-buffer.h
===================================================================
--- src/write-buffer.h	(revision 0)
+++ src/write-buffer.h	(revision 0)
@@ -0,0 +1,59 @@
+// 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
+//       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.
+
+#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_