Fix invalid reuse of weak global handle in GetScriptWrapper.

This fixes a direct usage of a weak global handle in GetScriptWrapper
that just casted it to a strong local handle, while a subsequent GC
might clear it. Handlepocalypse anyone?

R=machenbach@chromium.org
BUG=v8:2988
TEST=mjsunit/regress/regress-2988

Review URL: https://codereview.chromium.org/67273004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17622 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/handles.cc

@@ -242,9 +242,9 @@ static void ClearWrapperCache(v8::Isolate* v8_isolate,
 
 Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
   if (script->wrapper()->foreign_address() != NULL) {
-    // Return the script wrapper directly from the cache.
+    // Return a handle for the existing script wrapper from the cache.
     return Handle<JSValue>(
-        reinterpret_cast<JSValue**>(script->wrapper()->foreign_address()));
+        *reinterpret_cast<JSValue**>(script->wrapper()->foreign_address()));
   }
   Isolate* isolate = script->GetIsolate();
   // Construct a new script wrapper.
@@ -255,10 +255,10 @@ Handle<JSValue> GetScriptWrapper(Handle<Script> script) {
 
   // The allocation might have triggered a GC, which could have called this
   // function recursively, and a wrapper has already been created and cached.
-  // In that case, simply return the cached wrapper.
+  // In that case, simply return a handle for the cached wrapper.
   if (script->wrapper()->foreign_address() != NULL) {
     return Handle<JSValue>(
-        reinterpret_cast<JSValue**>(script->wrapper()->foreign_address()));
+        *reinterpret_cast<JSValue**>(script->wrapper()->foreign_address()));
   }
 
   result->set_value(*script);

test/mjsunit/regress/regress-2988.js

+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * 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.
+//     * Neither the name of Google Inc. 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 THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT
+// OWNER 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.
+
+// Flags: --allow-natives-syntax --gc-global --throws
+
+var f = eval("(function f() { throw 'kaboom'; })");
+
+// Prepare that next MessageHandler::MakeMessageObject will result in
+// reclamation of existing script wrapper while weak handle is used.
+%FunctionGetScript(f);
+%SetAllocationTimeout(1000, 2);
+
+// This call throws to the console but the --throws flag passed to this
+// test will make sure we don't count it as an actual failure.
+f();