Add custom typed ICs for pixel array loads.

src/ic.cc

Index: src/ic.cc
===================================================================
--- src/ic.cc	(revision 6456)
+++ src/ic.cc	(working copy)
@@ -1197,7 +1197,9 @@
         MaybeObject* probe =
             StubCache::ComputeKeyedLoadOrStoreExternalArray(*receiver, false);
         stub =
-            probe->IsFailure() ? NULL : Code::cast(probe->ToObjectUnchecked());
+          probe->IsFailure() ? NULL : Code::cast(probe->ToObjectUnchecked());
+      } else if (receiver->HasPixelElements()) {
+        stub = pixel_array_stub();

[Mads Ager (chromium), 2011/01/25 14:49:17]

Let's remove the pixel array code in the generic stub now that we have a special
IC stub?

[danno, 2011/01/25 20:56:29]

This occurred to me too, but I actually think we still need it... Otherwise how
do we handle pixel arrays in the case of a call site that goes megamorphic?
On 2011/01/25 14:49:17, Mads Ager wrote:

[Mads Ager (chromium), 2011/01/26 08:10:21]

True, we don't deal with it in that case and I guess it will not harm much to
leave it in the generic stub. 

However, can we share some of the code generation code in that case? Create a
static helper method GenerateLoadFromPixelArray that generates the code for
everything but the receiver check?

On 2011/01/25 20:56:29, danno wrote:

       } else if (receiver->HasIndexedInterceptor()) {
         stub = indexed_interceptor_stub();
       } else if (state == UNINITIALIZED &&