Add map check for COW elements to crankshaft array handling code.

src/hydrogen.cc

 // 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
@@ skipping 3903 matching lines @@
     AddInstruction(elements);
     length = AddInstruction(new(zone()) HExternalArrayLength(elements));
     checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
     HLoadExternalArrayPointer* external_elements =
         new(zone()) HLoadExternalArrayPointer(elements);
     AddInstruction(external_elements);
     return BuildExternalArrayElementAccess(external_elements, checked_key,
                                            val, map->elements_kind(), is_store);
   }
   ASSERT(map->has_fast_elements());
+  HInstruction* elements_cow_map_check = new(zone()) HCheckMap(

[Vyacheslav Egorov (Chromium), 2011/07/14 13:03:44]

I find the name of the variable confusing. We are checking exactly opposite
(that elements are NOT COW.

[Jakob Kummerow, 2011/07/14 14:44:49]

Done, sort of: I've removed the variable completely.

+      elements, isolate()->factory()->fixed_array_map());
   if (map->instance_type() == JS_ARRAY_TYPE) {
     length = AddInstruction(new(zone()) HJSArrayLength(object));
     checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
     AddInstruction(elements);
+    AddInstruction(elements_cow_map_check);

[Vyacheslav Egorov (Chromium), 2011/07/14 13:03:44]

This map check is redundant if !is_store.

Can you also extend the regression testcase that tests monomorphic keyed stores
(current testcase tests polymorphic stores)? 

[Jakob Kummerow, 2011/07/14 14:44:49]

Done.
Done.

   } else {
     AddInstruction(elements);
+    AddInstruction(elements_cow_map_check);

[Vyacheslav Egorov (Chromium), 2011/07/14 13:03:44]

Ditto.

[Jakob Kummerow, 2011/07/14 14:44:49]

Done.

     length = AddInstruction(new(zone()) HFixedArrayLength(elements));
     checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
   }
   if (is_store) {
     return new(zone()) HStoreKeyedFastElement(elements, checked_key, val);
   } else {
     return new(zone()) HLoadKeyedFastElement(elements, checked_key);
   }
 }
 
@@ skipping 85 matching lines @@
         typecheck->SetSuccessorAt(1, if_fastobject);
         current_block()->Finish(typecheck);
 
         set_current_block(if_jsarray);
         HInstruction* length = new(zone()) HJSArrayLength(object);
         AddInstruction(length);
         length->ClearFlag(HValue::kUseGVN);
         checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
         elements = AddInstruction(new(zone()) HLoadElements(object));
         elements->ClearFlag(HValue::kUseGVN);
+        AddInstruction(new(zone()) HCheckMap(

[Vyacheslav Egorov (Chromium), 2011/07/14 13:03:44]

redundant if !is_store

[Jakob Kummerow, 2011/07/14 14:44:49]

Done.

+              elements, isolate()->factory()->fixed_array_map()));
         if (is_store) {
           access = AddInstruction(
               new(zone()) HStoreKeyedFastElement(elements, checked_key, val));
         } else {
           access = AddInstruction(
               new(zone()) HLoadKeyedFastElement(elements, checked_key));
           Push(access);
         }
         *has_side_effects |= access->HasSideEffects();
         if (position != -1) {
           access->set_position(position);
         }
         if_jsarray->Goto(join);
 
         set_current_block(if_fastobject);
         elements = AddInstruction(new(zone()) HLoadElements(object));
         elements->ClearFlag(HValue::kUseGVN);
+        AddInstruction(new(zone()) HCheckMap(

[Vyacheslav Egorov (Chromium), 2011/07/14 13:03:44]

This map check is redundant if !is_store

[Jakob Kummerow, 2011/07/14 14:44:49]

Done.

+              elements, isolate()->factory()->fixed_array_map()));
         length = AddInstruction(new(zone()) HFixedArrayLength(elements));
         checked_key = AddInstruction(new(zone()) HBoundsCheck(key, length));
         if (is_store) {
           access = AddInstruction(
               new(zone()) HStoreKeyedFastElement(elements, checked_key, val));
         } else {
           access = AddInstruction(
               new(zone()) HLoadKeyedFastElement(elements, checked_key));
         }
       } else if (elements_kind == JSObject::DICTIONARY_ELEMENTS) {
@@ skipping 2630 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal