Only update the stub cache tables with monomorphic stubs used by

megamorphic call sites. This removes a lot of contention in the
tables.

Review URL: http://codereview.chromium.org/2813002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4853 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ic.cc

@@ -387,6 +387,7 @@ Object* CallICBase::TryCallAsFunction(Object* object) {
   return *delegate;
 }
 
+
 void CallICBase::ReceiverToObject(Handle<Object> object) {
   HandleScope scope;
   Handle<Object> receiver(object);
@@ -588,6 +589,9 @@ void CallICBase::UpdateCaches(LookupResult* lookup,
       state == MONOMORPHIC ||
       state == MONOMORPHIC_PROTOTYPE_FAILURE) {
     set_target(Code::cast(code));
+  } else if (state == MEGAMORPHIC) {
+    // Update the stub cache.
+    StubCache::Set(*name, GetCodeCacheMapForObject(*object), Code::cast(code));
   }
 
 #ifdef DEBUG
@@ -664,7 +668,6 @@ Object* LoadIC::Load(State state, Handle<Object> object, Handle<String> name) {
       Code* target = NULL;
       target = Builtins::builtin(Builtins::LoadIC_StringLength);
       set_target(target);
-      StubCache::Set(*name, map, target);
       return Smi::FromInt(String::cast(*object)->length());
     }
 
@@ -679,7 +682,6 @@ Object* LoadIC::Load(State state, Handle<Object> object, Handle<String> name) {
 
       Code* target = Builtins::builtin(Builtins::LoadIC_ArrayLength);
       set_target(target);
-      StubCache::Set(*name, map, target);
       return JSArray::cast(*object)->length();
     }
 
@@ -691,7 +693,6 @@ Object* LoadIC::Load(State state, Handle<Object> object, Handle<String> name) {
 #endif
       Code* target = Builtins::builtin(Builtins::LoadIC_FunctionPrototype);
       set_target(target);
-      StubCache::Set(*name, HeapObject::cast(*object)->map(), target);
       return Accessors::FunctionGetPrototype(*object, 0);
     }
   }
@@ -847,6 +848,9 @@ void LoadIC::UpdateCaches(LookupResult* lookup,
     set_target(Code::cast(code));
   } else if (state == MONOMORPHIC) {
     set_target(megamorphic_stub());
+  } else if (state == MEGAMORPHIC) {
+    // Update the stub cache.
+    StubCache::Set(*name, GetCodeCacheMapForObject(*object), Code::cast(code));
   }
 
 #ifdef DEBUG
@@ -1110,7 +1114,6 @@ Object* StoreIC::Store(State state,
     return *value;
   }
 
-
   // Use specialized code for setting the length of arrays.
   if (receiver->IsJSArray()
       && name->Equals(Heap::length_symbol())
@@ -1120,7 +1123,6 @@ Object* StoreIC::Store(State state,
 #endif
     Code* target = Builtins::builtin(Builtins::StoreIC_ArrayLength);
     set_target(target);
-    StubCache::Set(*name, HeapObject::cast(*object)->map(), target);
     return receiver->SetProperty(*name, *value, NONE);
   }
 
@@ -1208,8 +1210,11 @@ void StoreIC::UpdateCaches(LookupResult* lookup,
   if (state == UNINITIALIZED || state == MONOMORPHIC_PROTOTYPE_FAILURE) {
     set_target(Code::cast(code));
   } else if (state == MONOMORPHIC) {
-    // Only move to mega morphic if the target changes.
+    // Only move to megamorphic if the target changes.
     if (target() != Code::cast(code)) set_target(megamorphic_stub());
+  } else if (state == MEGAMORPHIC) {
+    // Update the stub cache.
+    StubCache::Set(*name, receiver->map(), Code::cast(code));
   }
 
 #ifdef DEBUG

src/stub-cache.cc

@@ -121,7 +121,7 @@ Object* StubCache::ComputeLoadNonexistent(String* name, JSObject* receiver) {
         receiver->map()->UpdateCodeCache(cache_name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -139,7 +139,7 @@ Object* StubCache::ComputeLoadField(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -158,7 +158,7 @@ Object* StubCache::ComputeLoadCallback(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -177,7 +177,7 @@ Object* StubCache::ComputeLoadConstant(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -194,13 +194,12 @@ Object* StubCache::ComputeLoadInterceptor(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
 Object* StubCache::ComputeLoadNormal(String* name, JSObject* receiver) {
-  Code* code = Builtins::builtin(Builtins::LoadIC_Normal);
-  return Set(name, receiver->map(), code);
+  return Builtins::builtin(Builtins::LoadIC_Normal);
 }
 
 
@@ -223,7 +222,7 @@ Object* StubCache::ComputeLoadGlobal(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -368,7 +367,7 @@ Object* StubCache::ComputeStoreField(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -385,7 +384,7 @@ Object* StubCache::ComputeStoreGlobal(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -403,7 +402,7 @@ Object* StubCache::ComputeStoreCallback(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -420,7 +419,7 @@ Object* StubCache::ComputeStoreInterceptor(String* name,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -486,7 +485,7 @@ Object* StubCache::ComputeCallConstant(int argc,
     Object* result = map->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, map, Code::cast(code));
+  return code;
 }
 
 
@@ -525,7 +524,7 @@ Object* StubCache::ComputeCallField(int argc,
     Object* result = map->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, map, Code::cast(code));
+  return code;
 }
 
 
@@ -563,7 +562,7 @@ Object* StubCache::ComputeCallInterceptor(int argc,
     Object* result = map->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, map, Code::cast(code));
+  return code;
 }
 
 
@@ -574,7 +573,7 @@ Object* StubCache::ComputeCallNormal(int argc,
                                      JSObject* receiver) {
   Object* code = ComputeCallNormal(argc, in_loop, kind);
   if (code->IsFailure()) return code;
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }
 
 
@@ -607,7 +606,7 @@ Object* StubCache::ComputeCallGlobal(int argc,
     Object* result = receiver->map()->UpdateCodeCache(name, Code::cast(code));
     if (result->IsFailure()) return result;
   }
-  return Set(name, receiver->map(), Code::cast(code));
+  return code;
 }