From a96b9156a357752cbe1aec39ce5bf9040bf3f8ca Mon Sep 17 00:00:00 2001
From: "ager@chromium.org"
 <ager@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Tue, 21 Jun 2011 08:07:45 +0000
Subject: [PATCH] Correctly handle non-array receivers in Array length setter.

BUG=v8:1491
TEST=mjsunit/regress/regress-1491.js

Review URL: http://codereview.chromium.org/7206038

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8343 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/accessors.cc                     | 23 ++++++++++------------
 test/mjsunit/regress/regress-1491.js | 38 ++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 13 deletions(-)
 create mode 100644 test/mjsunit/regress/regress-1491.js

diff --git a/src/accessors.cc b/src/accessors.cc
index d8df05e..806c679 100644
--- a/src/accessors.cc
+++ b/src/accessors.cc
@@ -102,6 +102,15 @@ Object* Accessors::FlattenNumber(Object* value) {
 
 MaybeObject* Accessors::ArraySetLength(JSObject* object, Object* value, void*) {
   Isolate* isolate = object->GetIsolate();
+
+  // This means one of the object's prototypes is a JSArray and the
+  // object does not have a 'length' property.  Calling SetProperty
+  // causes an infinite loop.
+  if (!object->IsJSArray()) {
+    return object->SetLocalPropertyIgnoreAttributes(
+        isolate->heap()->length_symbol(), value, NONE);
+  }
+
   value = FlattenNumber(value);
 
   // Need to call methods that may trigger GC.
@@ -117,20 +126,8 @@ MaybeObject* Accessors::ArraySetLength(JSObject* object, Object* value, void*) {
   Handle<Object> number_v = Execution::ToNumber(value_handle, &has_exception);
   if (has_exception) return Failure::Exception();
 
-  // Restore raw pointers,
-  object = *object_handle;
-  value = *value_handle;
-
   if (uint32_v->Number() == number_v->Number()) {
-    if (object->IsJSArray()) {
-      return JSArray::cast(object)->SetElementsLength(*uint32_v);
-    } else {
-      // This means one of the object's prototypes is a JSArray and
-      // the object does not have a 'length' property.
-      // Calling SetProperty causes an infinite loop.
-      return object->SetLocalPropertyIgnoreAttributes(
-          isolate->heap()->length_symbol(), value, NONE);
-    }
+    return Handle<JSArray>::cast(object_handle)->SetElementsLength(*uint32_v);
   }
   return isolate->Throw(
       *isolate->factory()->NewRangeError("invalid_array_length",
diff --git a/test/mjsunit/regress/regress-1491.js b/test/mjsunit/regress/regress-1491.js
new file mode 100644
index 0000000..1a3d3bf
--- /dev/null
+++ b/test/mjsunit/regress/regress-1491.js
@@ -0,0 +1,38 @@
+// Copyright 2011 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.
+
+// Test that the Array length accessor correctly deals with non-array
+// receivers.
+
+// Create an object with an array as the prototype.
+var o = Object.create([]);
+
+// Check that writing the length property of the non-array object
+// works as expected.
+var value = "asdf";
+o.length = value;
+assertEquals(value, o.length);
-- 
2.7.4