Do not change environment between simulate and scope with no observable...

Do not change environment between simulate and scope with no observable side-effects in HandlePropertyAssignment.

LChunkBuilder reconstructs the environment by applying simulates. A scope with no observable side-effects has no simulates. If the scope deoptimizes, then LChunkBuilder would miss the changes to the environment between the last simulate and the scope.

R=danno@chromium.org
BUG=v8:2671
TEST=mjsunit/regress/regress-2671.js

Review URL: https://chromiumcodereview.appspot.com/14793009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14584 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -7353,14 +7353,15 @@ void HOptimizedGraphBuilder::HandlePropertyAssignment(Assignment* expr) {
     // Keyed store.
     CHECK_ALIVE(VisitForValue(prop->key()));
     CHECK_ALIVE(VisitForValue(expr->value()));
-    HValue* value = Pop();
-    HValue* key = Pop();
-    HValue* object = Pop();
+    HValue* value = environment()->ExpressionStackAt(0);
+    HValue* key = environment()->ExpressionStackAt(1);
+    HValue* object = environment()->ExpressionStackAt(2);
     bool has_side_effects = false;
     HandleKeyedElementAccess(object, key, value, expr, expr->AssignmentId(),
                              expr->position(),
                              true,  // is_store
                              &has_side_effects);
+    Drop(3);
     Push(value);
     AddSimulate(expr->AssignmentId(), REMOVABLE_SIMULATE);
     return ast_context()->ReturnValue(Pop());

test/mjsunit/regress/regress-2671.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
+
+var y;
+function f() {
+  var a = [];
+  a[20] = 0;
+  y = 3;
+  var i = 7 * (y + -0);
+  a[i] = 1/y;
+  assertFalse(isNaN(a[i]));
+}
+
+f();
+f();
+f();
+%OptimizeFunctionOnNextCall(f);
+f();
+