Do not ignore an empty context with extension when creating a scope object.

Runtime_DebugEvaluate creates an empty context which is not correctly handled in FullCodeGenerator::ContextSlotOperandCheckExtensions because the corresponding scope indicates that it has no context.

BUG=crbug.com/107996
TEST=test/mjsunit/regress/regress-crbug-107996.js

Review URL: https://chromiumcodereview.appspot.com/9310027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10582 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/scopes.cc

@@ -149,12 +149,10 @@ Scope::Scope(Scope* inner_scope,
   SetDefaults(type, NULL, scope_info);
   if (!scope_info.is_null()) {
     num_heap_slots_ = scope_info_->ContextLength();
-    if (*scope_info != ScopeInfo::Empty()) {
-      language_mode_ = scope_info->language_mode();
-    }
-  } else if (is_with_scope()) {
-    num_heap_slots_ = Context::MIN_CONTEXT_SLOTS;
   }
+  // Ensure at least MIN_CONTEXT_SLOTS to indicate a materialized context.
+  num_heap_slots_ = Max(num_heap_slots_,
+                        static_cast<int>(Context::MIN_CONTEXT_SLOTS));
   AddInnerScope(inner_scope);
 }
 

test/mjsunit/regress/regress-crbug-107996.js

+// Copyright 2012 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: --expose-debug-as debug
+
+Debug = debug.Debug;
+
+Debug.setListener(listener);
+
+var fourteen;
+var four_in_debugger = [];
+
+function listener(event, exec_state, event_data, data) {
+  if (event == Debug.DebugEvent.Break) {
+    for (var i = 0; i < exec_state.frameCount(); i++) {
+      var frame = exec_state.frame(i);
+      four_in_debugger[i] = frame.evaluate("four", false).value();
+    }
+  }
+}
+
+function f1() {
+  var three = 3;
+  var four = 4;
+  (function f2() {
+     var seven = 7;
+     (function f3() {
+        debugger;
+        fourteen = three + four + seven;
+     })();
+  })();
+}
+
+f1();
+assertEquals(14, fourteen);
+assertEquals(4, four_in_debugger[0]);
+assertEquals(4, four_in_debugger[1]);
+assertEquals(4, four_in_debugger[2]);
+
+Debug.setListener(null);