Upgrade V8 to version 4.9.385.28
https://chromium.googlesource.com/v8/v8/+/4.9.385.28
FPIIM-449
Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/profiler/circular-queue.h b/src/profiler/circular-queue.h
new file mode 100644
index 0000000..272843b
--- /dev/null
+++ b/src/profiler/circular-queue.h
@@ -0,0 +1,69 @@
+// Copyright 2010 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.
+
+#ifndef V8_PROFILER_CIRCULAR_QUEUE_H_
+#define V8_PROFILER_CIRCULAR_QUEUE_H_
+
+#include "src/base/atomicops.h"
+#include "src/globals.h"
+
+namespace v8 {
+namespace internal {
+
+
+// Lock-free cache-friendly sampling circular queue for large
+// records. Intended for fast transfer of large records between a
+// single producer and a single consumer. If the queue is full,
+// StartEnqueue will return NULL. The queue is designed with
+// a goal in mind to evade cache lines thrashing by preventing
+// simultaneous reads and writes to adjanced memory locations.
+template<typename T, unsigned Length>
+class SamplingCircularQueue {
+ public:
+ // Executed on the application thread.
+ SamplingCircularQueue();
+ ~SamplingCircularQueue();
+
+ // StartEnqueue returns a pointer to a memory location for storing the next
+ // record or NULL if all entries are full at the moment.
+ T* StartEnqueue();
+ // Notifies the queue that the producer has complete writing data into the
+ // memory returned by StartEnqueue and it can be passed to the consumer.
+ void FinishEnqueue();
+
+ // Executed on the consumer (analyzer) thread.
+ // Retrieves, but does not remove, the head of this queue, returning NULL
+ // if this queue is empty. After the record had been read by a consumer,
+ // Remove must be called.
+ T* Peek();
+ void Remove();
+
+ private:
+ // Reserved values for the entry marker.
+ enum {
+ kEmpty, // Marks clean (processed) entries.
+ kFull // Marks entries already filled by the producer but not yet
+ // completely processed by the consumer.
+ };
+
+ struct V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry {
+ Entry() : marker(kEmpty) {}
+ T record;
+ base::Atomic32 marker;
+ };
+
+ Entry* Next(Entry* entry);
+
+ Entry buffer_[Length];
+ V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry* enqueue_pos_;
+ V8_ALIGNED(PROCESSOR_CACHE_LINE_SIZE) Entry* dequeue_pos_;
+
+ DISALLOW_COPY_AND_ASSIGN(SamplingCircularQueue);
+};
+
+
+} // namespace internal
+} // namespace v8
+
+#endif // V8_PROFILER_CIRCULAR_QUEUE_H_