Add missing files from last commit.

src/write-buffer.h

Index: src/write-buffer.h
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+// 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 {
+
+
+// Used to implement the write barrier by collecting addresses of pointers
+// between spaces.
+class WriteBuffer : public AllStatic {
+ public:
+  static Address TopAddress() { return reinterpret_cast<Address>(&top_); }
+
+  static void Setup();
+  static void TearDown();
+
+  static inline void Mark(Address addr) {
+    *top_++ = addr;
+    if ((reinterpret_cast<uintptr_t>(top_) & kWriteBufferOverflowBit) != 0) {
+      ASSERT(top_ == limit_);
+      Compact();
+    } else {
+      ASSERT(top_ < limit_);
+    }
+  }
+
+  static const int kWriteBufferOverflowBit = 1 << 15;
+  static const int kWriteBufferSize = kWriteBufferOverflowBit;
+
+ private:
+  static Address* top_;
+  static Address* start_;
+  static Address* limit_;
+  static VirtualMemory* virtual_memory_;
+
+  static void Compact();
+};
+
+} }  // namespace v8::internal
+
+#endif  // V8_WRITE_BARRIER_H_