--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/assembler/LinkBuffer.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 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.
+ *
+ * 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 LinkBuffer_h
+#define LinkBuffer_h
+
+#if ENABLE(ASSEMBLER)
+
+#include <MacroAssembler.h>
+#include <wtf/Noncopyable.h>
+
+namespace JSC {
+
+// LinkBuffer:
+//
+// This class assists in linking code generated by the macro assembler, once code generation
+// has been completed, and the code has been copied to is final location in memory.  At this
+// time pointers to labels within the code may be resolved, and relative offsets to external
+// addresses may be fixed.
+//
+// Specifically:
+//   * Jump objects may be linked to external targets,
+//   * The address of Jump objects may taken, such that it can later be relinked.
+//   * The return address of a Call may be acquired.
+//   * The address of a Label pointing into the code may be resolved.
+//   * The value referenced by a DataLabel may be set.
+//
+class LinkBuffer : public Noncopyable {
+    typedef MacroAssemblerCodeRef CodeRef;
+    typedef MacroAssembler::Label Label;
+    typedef MacroAssembler::Jump Jump;
+    typedef MacroAssembler::JumpList JumpList;
+    typedef MacroAssembler::Call Call;
+    typedef MacroAssembler::DataLabel32 DataLabel32;
+    typedef MacroAssembler::DataLabelPtr DataLabelPtr;
+
+public:
+    // Note: Initialization sequence is significant, since executablePool is a PassRefPtr.
+    //       First, executablePool is copied into m_executablePool, then the initialization of
+    //       m_code uses m_executablePool, *not* executablePool, since this is no longer valid.
+    LinkBuffer(MacroAssembler* masm, PassRefPtr<ExecutablePool> executablePool)
+        : m_executablePool(executablePool)
+        , m_code(masm->m_assembler.executableCopy(m_executablePool.get()))
+        , m_size(masm->m_assembler.size())
+#ifndef NDEBUG
+        , m_completed(false)
+#endif
+    {
+    }
+
+    ~LinkBuffer()
+    {
+        ASSERT(m_completed);
+    }
+
+    // These methods are used to link or set values at code generation time.
+
+    void link(Call call, FunctionPtr function)
+    {
+        ASSERT(call.isFlagSet(Call::Linkable));
+        MacroAssembler::linkCall(code(), call, function);
+    }
+    
+    void link(Jump jump, CodeLocationLabel label)
+    {
+        MacroAssembler::linkJump(code(), jump, label);
+    }
+
+    void link(JumpList list, CodeLocationLabel label)
+    {
+        for (unsigned i = 0; i < list.m_jumps.size(); ++i)
+            MacroAssembler::linkJump(code(), list.m_jumps[i], label);
+    }
+
+    void patch(DataLabelPtr label, void* value)
+    {
+        MacroAssembler::linkPointer(code(), label.m_label, value);
+    }
+
+    void patch(DataLabelPtr label, CodeLocationLabel value)
+    {
+        MacroAssembler::linkPointer(code(), label.m_label, value.executableAddress());
+    }
+
+    // These methods are used to obtain handles to allow the code to be relinked / repatched later.
+
+    CodeLocationCall locationOf(Call call)
+    {
+        ASSERT(call.isFlagSet(Call::Linkable));
+        ASSERT(!call.isFlagSet(Call::Near));
+        return CodeLocationCall(MacroAssembler::getLinkerAddress(code(), call.m_jmp));
+    }
+
+    CodeLocationNearCall locationOfNearCall(Call call)
+    {
+        ASSERT(call.isFlagSet(Call::Linkable));
+        ASSERT(call.isFlagSet(Call::Near));
+        return CodeLocationNearCall(MacroAssembler::getLinkerAddress(code(), call.m_jmp));
+    }
+
+    CodeLocationLabel locationOf(Label label)
+    {
+        return CodeLocationLabel(MacroAssembler::getLinkerAddress(code(), label.m_label));
+    }
+
+    CodeLocationDataLabelPtr locationOf(DataLabelPtr label)
+    {
+        return CodeLocationDataLabelPtr(MacroAssembler::getLinkerAddress(code(), label.m_label));
+    }
+
+    CodeLocationDataLabel32 locationOf(DataLabel32 label)
+    {
+        return CodeLocationDataLabel32(MacroAssembler::getLinkerAddress(code(), label.m_label));
+    }
+
+    // This method obtains the return address of the call, given as an offset from
+    // the start of the code.
+    unsigned returnAddressOffset(Call call)
+    {
+        return MacroAssembler::getLinkerCallReturnOffset(call);
+    }
+
+    // Upon completion of all patching either 'finalizeCode()' or 'finalizeCodeAddendum()' should be called
+    // once to complete generation of the code.  'finalizeCode()' is suited to situations
+    // where the executable pool must also be retained, the lighter-weight 'finalizeCodeAddendum()' is
+    // suited to adding to an existing allocation.
+    CodeRef finalizeCode()
+    {
+        performFinalization();
+
+        return CodeRef(m_code, m_executablePool, m_size);
+    }
+    CodeLocationLabel finalizeCodeAddendum()
+    {
+        performFinalization();
+
+        return CodeLocationLabel(code());
+    }
+
+private:
+    // Keep this private! - the underlying code should only be obtained externally via 
+    // finalizeCode() or finalizeCodeAddendum().
+    void* code()
+    {
+        return m_code;
+    }
+
+    void performFinalization()
+    {
+#ifndef NDEBUG
+        ASSERT(!m_completed);
+        m_completed = true;
+#endif
+
+        ExecutableAllocator::makeExecutable(code(), m_size);
+        ExecutableAllocator::cacheFlush(code(), m_size);
+    }
+
+    RefPtr<ExecutablePool> m_executablePool;
+    void* m_code;
+    size_t m_size;
+#ifndef NDEBUG
+    bool m_completed;
+#endif
+};
+
+} // namespace JSC
+
+#endif // ENABLE(ASSEMBLER)
+
+#endif // LinkBuffer_h