Create specialized code stubs for PixelArray loads.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index b8133ae15e43e3fe08a65114cb60b4c0d8d5300d..6a26f23d5397ea168409eace6dc7b0dcb68fbe4d 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -3491,8 +3491,10 @@ static MaybeObject* Runtime_KeyedGetProperty(Arguments args) {
     HandleScope scope;
     Handle<String> str = args.at<String>(0);
     int index = Smi::cast(args[1])->value();
-    Handle<Object> result = GetCharAt(str, index);
-    return *result;
+    if (index >= 0 && index < str->length()) {

[Mads Ager (chromium), 2011/02/01 12:02:12]

Good catch! Thanks!

[Søren Thygesen Gjesse, 2011/02/01 12:02:56]

Is this a bug-fix? If so maybe there should be a regression test.

[danno, 2011/02/03 12:53:26]

There's actually an existing test case that wasn't quite sufficient to cause
this problem to show up in debug mode (although it did in release!) since it
didn't call a function a sufficient number of times to cause all of the map IC
transitions to land in the generic keyed load IC: regress-900966.js. I augmented
the test case to make sure it covers all of the transitions.

+      Handle<Object> result = GetCharAt(str, index);
+      return *result;
+    }
   }
 
   // Fall back to GetObjectProperty.