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+/*
+ * Copyright (C) 2013, 2014 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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 CodeBlockSet_h
+#define CodeBlockSet_h
+
+#include "GCSegmentedArray.h"
+#include "HeapOperation.h"
+#include <wtf/HashSet.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/PassRefPtr.h>
+#include <wtf/PrintStream.h>
+#include <wtf/RefPtr.h>
+
+namespace JSC {
+
+class BlockAllocator;
+class CodeBlock;
+class Heap;
+class JSCell;
+class SlotVisitor;
+
+// CodeBlockSet tracks all CodeBlocks. Every CodeBlock starts out with one
+// reference coming in from GC. The GC is responsible for freeing CodeBlocks
+// once they hasOneRef() and nobody is running code from that CodeBlock.
+
+class CodeBlockSet {
+    WTF_MAKE_NONCOPYABLE(CodeBlockSet);
+
+public:
+    CodeBlockSet(BlockAllocator&);
+    ~CodeBlockSet();
+    
+    // Add a CodeBlock. This is only called by CodeBlock constructors.
+    void add(PassRefPtr<CodeBlock>);
+    
+    // Clear mark bits for certain CodeBlocks depending on the type of collection.
+    void clearMarksForEdenCollection(const Vector<const JSCell*>&);
+
+    // Clear all mark bits for all CodeBlocks.
+    void clearMarksForFullCollection();
+
+    // Mark a pointer that may be a CodeBlock that belongs to the set of DFG
+    // blocks. This is defined in CodeBlock.h.
+    void mark(CodeBlock* candidateCodeBlock);
+    void mark(void* candidateCodeBlock);
+    
+    // Delete all code blocks that are only referenced by this set (i.e. owned
+    // by this set), and that have not been marked.
+    void deleteUnmarkedAndUnreferenced(HeapOperation);
+    
+    void remove(CodeBlock*);
+    
+    // Trace all marked code blocks. The CodeBlock is free to make use of
+    // mayBeExecuting.
+    void traceMarked(SlotVisitor&);
+
+    // Add all currently executing CodeBlocks to the remembered set to be 
+    // re-scanned during the next collection.
+    void rememberCurrentlyExecutingCodeBlocks(Heap*);
+
+    // Visits each CodeBlock in the heap until the visitor function returns true
+    // to indicate that it is done iterating, or until every CodeBlock has been
+    // visited.
+    template<typename Functor> void iterate(Functor& functor)
+    {
+        for (auto& codeBlock : m_oldCodeBlocks) {
+            bool done = functor(codeBlock);
+            if (done)
+                return;
+        }
+
+        for (auto& codeBlock : m_newCodeBlocks) {
+            bool done = functor(codeBlock);
+            if (done)
+                return;
+        }
+    }
+    
+    void dump(PrintStream&) const;
+
+private:
+    void clearMarksForCodeBlocksInRememberedExecutables(const Vector<const JSCell*>&);
+    void promoteYoungCodeBlocks();
+
+    // This is not a set of RefPtr<CodeBlock> because we need to be able to find
+    // arbitrary bogus pointers. I could have written a thingy that had peek types
+    // and all, but that seemed like overkill.
+    HashSet<CodeBlock*> m_oldCodeBlocks;
+    HashSet<CodeBlock*> m_newCodeBlocks;
+    GCSegmentedArray<CodeBlock*> m_currentlyExecuting;
+};
+
+} // namespace JSC
+
+#endif // CodeBlockSet_h
+