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diff --git a/js/src/methodjit/Retcon.h b/js/src/methodjit/Retcon.h
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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=4 sw=4 et tw=99:
+ *
+ * ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is Mozilla Jaegermonkey.
+ *
+ * The Initial Developer of the Original Code is the Mozilla Foundation.
+ *
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Andrew Drake <drakedevel@gmail.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+/*
+ * Retroactive continuity ("retcon") refers to the retroactive modification
+ * or reinterpretation of established facts. 
+ */
+
+#if !defined jsjaeger_retcon_h__ && defined JS_METHODJIT
+#define jsjaeger_retcon_h__
+
+#include "jscntxt.h"
+#include "jsscript.h"
+#include "MethodJIT.h"
+#include "Compiler.h"
+
+namespace js {
+namespace mjit {
+
+/*
+ * A problem often arises where, for one reason or another, a piece of code
+ * wants to touch the script->code, but isn't expecting JSOP_TRAP. This allows
+ * one to temporarily remove JSOP_TRAPs from the instruction stream (without
+ * copying) and automatically re-add them on scope exit.
+ */
+class AutoScriptRetrapper
+{
+  public:
+    AutoScriptRetrapper(JSContext *cx1, JSScript *script1) :
+        cx(cx1), script(script1), traps(cx) {};
+    ~AutoScriptRetrapper();
+
+    bool untrap(jsbytecode *pc);
+
+  private:
+    JSContext *cx;
+    JSScript *script;
+    Vector<jsbytecode*> traps;
+};
+
+/*
+ * This class is responsible for sanely re-JITing a script and fixing up
+ * the world. If you ever change the code associated with a JSScript, or
+ * otherwise would cause existing JITed code to be incorrect, you /must/ use
+ * this to invalidate and potentially re-compile the existing JITed code,
+ * fixing up the stack in the process.
+ */
+class Recompiler {
+    struct PatchableAddress {
+        void **location;
+        CallSite callSite;
+    };
+    
+public:
+    Recompiler(JSContext *cx, JSScript *script);
+    
+    bool recompile();
+
+private:
+    JSContext *cx;
+    JSScript *script;
+    
+    PatchableAddress findPatch(JITScript *jit, void **location);
+    void applyPatch(Compiler& c, PatchableAddress& toPatch);
+    bool recompile(JSStackFrame *fp, Vector<PatchableAddress> &patches,
+                   Vector<CallSite> &sites);
+    bool saveTraps(JITScript *jit, Vector<CallSite> *sites);
+};
+
+} /* namespace mjit */
+} /* namespace js */
+
+#endif
+