crankshaft support for api method calls

src/stub-cache.cc

Index: src/stub-cache.cc
diff --git a/src/stub-cache.cc b/src/stub-cache.cc
index f715573556257b93a5b268a6b357d3e1c3ce5109..4afe357c9ad36765ed91c44ce035e44995fe07d3 100644
--- a/src/stub-cache.cc
+++ b/src/stub-cache.cc
@@ -1938,9 +1938,9 @@ CallOptimization::CallOptimization(Handle<JSFunction> function) {
 
 
 Handle<Map> CallOptimization::LookupHolderOfExpectedType(
-    Handle<JSObject> receiver,
-    Handle<JSObject> object,
-    Handle<JSObject> holder,
+    Handle<Map> receiver_map,
+    Handle<Map> object_map,
+    Handle<Map> holder_map,
     HolderLookup* holder_lookup) const {
   ASSERT(is_simple_api_call());
   ASSERT_EQ(kHolderNotFound, *holder_lookup);
@@ -1951,26 +1951,26 @@ Handle<Map> CallOptimization::LookupHolderOfExpectedType(
     return map_to_holder;
   }
   // walk down the prototype chain to the object
-  while (!receiver.is_identical_to(object)) {
+  while (!receiver_map.is_identical_to(object_map)) {
     *holder_lookup = kHolderIsPrototypeOfMap;
-    map_to_holder = Handle<Map>(receiver->map());
-    receiver = Handle<JSObject>(JSObject::cast(map_to_holder->prototype()));
+    map_to_holder = receiver_map;
+    receiver_map =
+        Handle<Map>(JSObject::cast(map_to_holder->prototype())->map());
   }
   // start looking for the holder
-  while (!object.is_identical_to(holder)) {
-    Handle<Map> object_map(object->map());
+  while (!object_map.is_identical_to(holder_map)) {

[Toon Verwaest, 2014/01/29 13:22:39]

Please extract this implicit magic to an explicit
"CanElideApiHolderPrototypeChainCheck" with a comment indicating that we can
remove it if the API holder is between the receiver and the holder, which is
checked by the regular prototype chain check.

     if (expected_receiver_type_->IsTemplateFor(*object_map)) {
       return map_to_holder;
     }
+    *holder_lookup = kHolderIsPrototypeOfMap;
+    map_to_holder = object_map;
+    object_map = Handle<Map>(JSObject::cast(object_map->prototype())->map());
     if (!object_map->is_hidden_prototype()) {
       *holder_lookup = kHolderNotFound;
       return Handle<Map>::null();
     }
-    *holder_lookup = kHolderIsPrototypeOfMap;
-    map_to_holder = object_map;
-    object = Handle<JSObject>(JSObject::cast(object_map->prototype()));
   }
-  if (expected_receiver_type_->IsTemplateFor(holder->map())) {
+  if (expected_receiver_type_->IsTemplateFor(*object_map)) {
     return map_to_holder;
   }
   *holder_lookup = kHolderNotFound;