Correctly materialize arguments object in Runtime_DebugEvaluate.

The problem was that if the # arguments specified in the function
declaration and the # arguments passed to the function are not
the same, we use an arguments adapter frame to make it work. This
confuses the existing implementation to materialize the arguments
object.

R=peter.rybin@gmail.com
BUG=222893

Review URL: https://chromiumcodereview.appspot.com/12674027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14059 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/runtime.cc

@@ -11573,19 +11573,10 @@ static Handle<Object> GetArgumentsObject(Isolate* isolate,
     }
   }
 
-  Handle<JSFunction> function(JSFunction::cast(frame_inspector->GetFunction()));
-  int length = frame_inspector->GetParametersCount();
-  Handle<JSObject> arguments =
-      isolate->factory()->NewArgumentsObject(function, length);
-  Handle<FixedArray> array = isolate->factory()->NewFixedArray(length);
-
-  AssertNoAllocation no_gc;
-  WriteBarrierMode mode = array->GetWriteBarrierMode(no_gc);
-  for (int i = 0; i < length; i++) {
-    array->set(i, frame_inspector->GetParameter(i), mode);
-  }
-  arguments->set_elements(*array);
-  return arguments;
+  // FunctionGetArguments can't return a non-Object.
+  return Handle<JSObject>(JSObject::cast(
+      Accessors::FunctionGetArguments(frame_inspector->GetFunction(),
+                                      NULL)->ToObjectUnchecked()), isolate);
 }
 
 

test/mjsunit/regress/regress-crbug-222893.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: --expose-debug-as debug
+
+Debug = debug.Debug
+
+var error = null;
+var array = ["a", "b", "c"];
+
+function listener(event, exec_state, event_data, data) {
+  try {
+    if (event == Debug.DebugEvent.Break) {
+      assertArrayEquals(array,
+                        exec_state.frame(0).evaluate('arguments').value());
+    }
+  } catch (e) {
+    error = e;
+  }
+};
+
+Debug.setListener(listener);
+
+
+function f(a, b) {
+  arguments;
+  debugger;  // Arguments object is already materialized.
+}
+
+f.apply(this, array);
+f("a", "b", "c");
+assertNull(error);
+
+function g(a, b) {
+  debugger;  // Arguments object is not yet materialized.
+}
+g.apply(this, array);
+g("a", "b", "c");
+assertNull(error);
+