Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 120 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/interpreter/RegisterFile.h b/Source/JavaScriptCore/interpreter/RegisterFile.h
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+++ b/Source/JavaScriptCore/interpreter/RegisterFile.h
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+/*
+ * Copyright (C) 2008, 2009 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.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") 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 APPLE AND ITS 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 APPLE OR ITS 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 RegisterFile_h
+#define RegisterFile_h
+
+#include "ExecutableAllocator.h"
+#include "Register.h"
+#include <wtf/Noncopyable.h>
+#include <wtf/PageReservation.h>
+#include <wtf/VMTags.h>
+
+namespace JSC {
+
+    class ConservativeRoots;
+    class DFGCodeBlocks;
+
+    class RegisterFile {
+        WTF_MAKE_NONCOPYABLE(RegisterFile);
+    public:
+        enum CallFrameHeaderEntry {
+            CallFrameHeaderSize = 6,
+
+            ArgumentCount = -6,
+            CallerFrame = -5,
+            Callee = -4,
+            ScopeChain = -3,
+            ReturnPC = -2, // This is either an Instruction* or a pointer into JIT generated code stored as an Instruction*.
+            CodeBlock = -1,
+        };
+
+        static const size_t defaultCapacity = 512 * 1024;
+        static const size_t commitSize = 16 * 1024;
+        // Allow 8k of excess registers before we start trying to reap the registerfile
+        static const ptrdiff_t maxExcessCapacity = 8 * 1024;
+
+        RegisterFile(size_t capacity = defaultCapacity);
+        ~RegisterFile();
+        
+        void gatherConservativeRoots(ConservativeRoots&);
+        void gatherConservativeRoots(ConservativeRoots&, DFGCodeBlocks&);
+
+        Register* begin() const { return static_cast<Register*>(m_reservation.base()); }
+        Register* end() const { return m_end; }
+        size_t size() const { return end() - begin(); }
+
+        bool grow(Register*);
+        void shrink(Register*);
+        
+        static size_t committedByteCount();
+        static void initializeThreading();
+
+        Register* const * addressOfEnd() const
+        {
+            return &m_end;
+        }
+
+    private:
+        bool growSlowCase(Register*);
+        void releaseExcessCapacity();
+        void addToCommittedByteCount(long);
+        Register* m_end;
+        Register* m_commitEnd;
+        PageReservation m_reservation;
+    };
+
+    inline RegisterFile::RegisterFile(size_t capacity)
+        : m_end(0)
+    {
+        ASSERT(capacity && isPageAligned(capacity));
+
+        m_reservation = PageReservation::reserve(roundUpAllocationSize(capacity * sizeof(Register), commitSize), OSAllocator::JSVMStackPages);
+        m_end = static_cast<Register*>(m_reservation.base());
+        m_commitEnd = static_cast<Register*>(m_reservation.base());
+    }
+
+    inline void RegisterFile::shrink(Register* newEnd)
+    {
+        if (newEnd >= m_end)
+            return;
+        m_end = newEnd;
+        if (m_end == m_reservation.base() && (m_commitEnd - begin()) >= maxExcessCapacity)
+            releaseExcessCapacity();
+    }
+
+    inline bool RegisterFile::grow(Register* newEnd)
+    {
+        if (newEnd <= m_end)
+            return true;
+        return growSlowCase(newEnd);
+    }
+
+} // namespace JSC
+
+#endif // RegisterFile_h