Add a soft-deopt in keyed element access when current IC is pre-monomorphic and no type feedback wa…

src/ic.cc

 // Copyright 2012 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 1350 matching lines @@
                                ICMissMode miss_mode) {
   if (MigrateDeprecated(object)) {
     return Runtime::GetObjectPropertyOrFail(isolate(), object, key);
   }
 
   // Check for values that can be converted into an internalized string directly
   // or is representable as a smi.
   key = TryConvertKey(key, isolate());
 
   if (key->IsInternalizedString()) {
     return LoadIC::Load(object, Handle<String>::cast(key));

[danno, 2013/10/21 16:35:59]

Don't you need to install the generic stub here, too? With a corresponding
trace?

[Hannes Payer (out of office), 2013/10/22 09:29:30]

Done.

   }
 
-  if (FLAG_use_ic && !object->IsAccessCheckNeeded()) {
-    ASSERT(!object->IsJSGlobalProxy());
+  if (FLAG_use_ic) {
     Handle<Code> stub = generic_stub();
-    if (miss_mode == MISS_FORCE_GENERIC) {
+    if (!object->IsAccessCheckNeeded()) {
+      ASSERT(!object->IsJSGlobalProxy());
+      if (miss_mode == MISS_FORCE_GENERIC) {
+        TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "force generic");
+      } else if (object->IsString() && key->IsNumber()) {
+        if (state() == UNINITIALIZED) stub = string_stub();

[danno, 2013/10/21 16:35:59]

need else here to TRACE_GENERIC

[Hannes Payer (out of office), 2013/10/22 09:29:30]

Done.

+      } else if (object->IsJSObject()) {
+        Handle<JSObject> receiver = Handle<JSObject>::cast(object);
+        if (receiver->elements()->map() ==
+            isolate()->heap()->non_strict_arguments_elements_map()) {
+          stub = non_strict_arguments_stub();
+        } else if (receiver->HasIndexedInterceptor()) {
+          stub = indexed_interceptor_stub();
+        } else if (!key->ToSmi()->IsFailure() &&
+                   (!target().is_identical_to(non_strict_arguments_stub()))) {
+          stub = LoadElementStub(receiver);
+        }

[danno, 2013/10/21 16:35:59]

need else here to TRACE_GENERIC

[Hannes Payer (out of office), 2013/10/22 09:29:30]

Done.

+      }
+    } else {
       TRACE_GENERIC_IC(isolate(), "KeyedLoadIC", "force generic");

[danno, 2013/10/21 16:35:59]

Comment is wrong. Should not be "force generic", but rather "access check
needed"

[Hannes Payer (out of office), 2013/10/22 09:29:30]

Done.

-    } else if (object->IsString() && key->IsNumber()) {
-      if (state() == UNINITIALIZED) stub = string_stub();
-    } else if (object->IsJSObject()) {
-      Handle<JSObject> receiver = Handle<JSObject>::cast(object);
-      if (receiver->elements()->map() ==
-          isolate()->heap()->non_strict_arguments_elements_map()) {
-        stub = non_strict_arguments_stub();
-      } else if (receiver->HasIndexedInterceptor()) {
-        stub = indexed_interceptor_stub();
-      } else if (!key->ToSmi()->IsFailure() &&
-                 (!target().is_identical_to(non_strict_arguments_stub()))) {
-        stub = LoadElementStub(receiver);
-      }
     }
-
     ASSERT(!stub.is_null());
     set_target(*stub);
     TRACE_IC("LoadIC", key);
   }
 
-
   return Runtime::GetObjectPropertyOrFail(isolate(), object, key);
 }
 
 
 static bool LookupForWrite(Handle<JSObject> receiver,
                            Handle<String> name,
                            Handle<Object> value,
                            LookupResult* lookup,
                            IC* ic) {
   Handle<JSObject> holder = receiver;
@@ skipping 564 matching lines @@
         }
       } else {
         TRACE_GENERIC_IC(isolate(), "KeyedStoreIC", "not an object");
       }
     } else {
       TRACE_GENERIC_IC(isolate(), "KeyedStoreIC", "force generic");
     }
     ASSERT(!stub.is_null());
     set_target(*stub);
     TRACE_IC("StoreIC", key);
+  } else if (FLAG_use_ic) {
+     set_target(*generic_stub());
+     TRACE_GENERIC_IC(isolate(), "KeyedStoreIC", "force generic");
+     TRACE_IC("StoreIC", key);
   }
 
   return Runtime::SetObjectPropertyOrFail(
       isolate(), object , key, value, NONE, strict_mode());
 }
 
 
 #undef TRACE_IC
 
 
@@ skipping 719 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal