Fix bug in assigned variables analysis.

Property stores were not visited correctly by the visitor.
I fixed this issue by visiting property stores by visiting 
receiver and key directly (and not calling visit on the lhs property
 ast node)

Review URL: http://codereview.chromium.org/903003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4117 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/data-flow.cc

@@ -1360,17 +1360,21 @@ void AssignedVariablesAnalyzer::VisitCatchExtensionObject(
 void AssignedVariablesAnalyzer::VisitAssignment(Assignment* expr) {
   ASSERT(av_.IsEmpty());
 
-  Visit(expr->target());
-
-  ProcessExpression(expr->value());
-
-  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
-  if (var != NULL) RecordAssignedVar(var);
-
-  // If we have a variable as a receiver in a property store, check if
-  // we can mark it as trivial.
   if (expr->target()->AsProperty() != NULL) {
+    // Visit receiver and key of property store and rhs.
+    Visit(expr->target()->AsProperty()->obj());
+    ProcessExpression(expr->target()->AsProperty()->key());
+    ProcessExpression(expr->value());
+
+    // If we have a variable as a receiver in a property store, check if
+    // we can mark it as trivial.
     MarkIfTrivial(expr->target()->AsProperty()->obj());
+  } else {
+    Visit(expr->target());
+    ProcessExpression(expr->value());
+
+    Variable* var = expr->target()->AsVariableProxy()->AsVariable();
+    if (var != NULL) RecordAssignedVar(var);
   }
 }
 

test/mjsunit/regress/regress-643.js

+// Copyright 2010 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.
+
+// Regression test for http://code.google.com/p/v8/issues/detail?id=643.
+
+function f() {
+  var test = {x:1};
+  var a = test;
+  a.x = a = 42;
+  return test.x;
+}
+
+assertEquals(42, f());