Cache IC handlers on the prototype's map if possible

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index b01c49d2b4fcb66b8f949b622e1c9ea1d1c0d2f5..373109220f5cb3a3b9f3eb5693410c6349120e88 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -4966,11 +4966,9 @@ void Code::set_constant_pool(Object* value) {
 }
 
 
-Code::Flags Code::ComputeFlags(Kind kind,
-                               InlineCacheState ic_state,
-                               ExtraICState extra_ic_state,
-                               StubType type,
-                               InlineCacheHolderFlag holder) {
+Code::Flags Code::ComputeFlags(Kind kind, InlineCacheState ic_state,
+                               ExtraICState extra_ic_state, StubType type,
+                               CacheHolderFlag holder) {
   // Compute the bit mask.
   unsigned int bits = KindField::encode(kind)
       | ICStateField::encode(ic_state)
@@ -4983,15 +4981,14 @@ Code::Flags Code::ComputeFlags(Kind kind,
 
 Code::Flags Code::ComputeMonomorphicFlags(Kind kind,
                                           ExtraICState extra_ic_state,
-                                          InlineCacheHolderFlag holder,
+                                          CacheHolderFlag holder,
                                           StubType type) {
   return ComputeFlags(kind, MONOMORPHIC, extra_ic_state, type, holder);
 }
 
 
-Code::Flags Code::ComputeHandlerFlags(Kind handler_kind,
-                                      StubType type,
-                                      InlineCacheHolderFlag holder) {
+Code::Flags Code::ComputeHandlerFlags(Kind handler_kind, StubType type,
+                                      CacheHolderFlag holder) {
   return ComputeFlags(Code::HANDLER, MONOMORPHIC, handler_kind, type, holder);
 }
 
@@ -5016,7 +5013,7 @@ Code::StubType Code::ExtractTypeFromFlags(Flags flags) {
 }
 
 
-InlineCacheHolderFlag Code::ExtractCacheHolderFromFlags(Flags flags) {
+CacheHolderFlag Code::ExtractCacheHolderFromFlags(Flags flags) {
   return CacheHolderField::decode(flags);
 }
 
@@ -5027,6 +5024,12 @@ Code::Flags Code::RemoveTypeFromFlags(Flags flags) {
 }
 
 
+Code::Flags Code::RemoveTypeAndHolderFromFlags(Flags flags) {
+  int bits = flags & ~TypeField::kMask & ~CacheHolderField::kMask;
+  return static_cast<Flags>(bits);
+}
+
+
 Code* Code::GetCodeFromTargetAddress(Address address) {
   HeapObject* code = HeapObject::FromAddress(address - Code::kHeaderSize);
   // GetCodeFromTargetAddress might be called when marking objects during mark