Propagate the information that a monomorphic prototype failure has

occured.  After a monomorphic prototype failure has been detected,
other monomorphic inline caches for the same type will have a code
object in the map's code cache which is not the current target.  We
recognize this case and use the code object that is in the cache
instead of going megamorphic.

Review URL: http://codereview.chromium.org/2928

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@331 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ic.h

@@ -81,8 +81,12 @@ class IC {
   Code* target() { return GetTargetAtAddress(address()); }
   inline Address address();
 
-  // Compute the current IC state based on the target stub and the receiver.
-  static State StateFrom(Code* target, Object* receiver);
+  // Compute the state of the current inline cache.  If the current
+  // inline cache is monomorphic, this might change the code cache in
+  // the receiver map and it might return a code object from the code
+  // cache in the receiver map that should be used as the new target.
+  static State ComputeCacheState(Code* target, Object* receiver,
+                                 Object* name, Object** new_target);
 
   // Clear the inline cache to initial state.
   static void Clear(Address address);
@@ -161,7 +165,7 @@ class CallIC: public IC {
  public:
   CallIC() : IC(EXTRA_CALL_FRAME) { ASSERT(target()->is_call_stub()); }
 
-  Object* LoadFunction(State state, Handle<Object> object, Handle<String> name);
+  Object* LoadFunction(Handle<Object> object, Handle<String> name);
 
 
   // Code generator routines.
@@ -179,7 +183,6 @@ class CallIC: public IC {
   // Update the inline cache and the global stub cache based on the
   // lookup result.
   void UpdateCaches(LookupResult* lookup,
-                    State state,
                     Handle<Object> object,
                     Handle<String> name);
 
@@ -197,7 +200,7 @@ class LoadIC: public IC {
  public:
   LoadIC() : IC(NO_EXTRA_FRAME) { ASSERT(target()->is_load_stub()); }
 
-  Object* Load(State state, Handle<Object> object, Handle<String> name);
+  Object* Load(Handle<Object> object, Handle<String> name);
 
   // Code generator routines.
   static void GenerateInitialize(MacroAssembler* masm);
@@ -219,7 +222,6 @@ class LoadIC: public IC {
   // Update the inline cache and the global stub cache based on the
   // lookup result.
   void UpdateCaches(LookupResult* lookup,
-                    State state,
                     Handle<Object> object,
                     Handle<String> name);
 
@@ -243,7 +245,7 @@ class KeyedLoadIC: public IC {
  public:
   KeyedLoadIC() : IC(NO_EXTRA_FRAME) { ASSERT(target()->is_keyed_load_stub()); }
 
-  Object* Load(State state, Handle<Object> object, Handle<Object> key);
+  Object* Load(Handle<Object> object, Handle<Object> key);
 
   // Code generator routines.
   static void GenerateMiss(MacroAssembler* masm);
@@ -256,7 +258,6 @@ class KeyedLoadIC: public IC {
 
   // Update the inline cache.
   void UpdateCaches(LookupResult* lookup,
-                    State state,
                     Handle<Object> object,
                     Handle<String> name);
 
@@ -283,8 +284,7 @@ class StoreIC: public IC {
  public:
   StoreIC() : IC(NO_EXTRA_FRAME) { ASSERT(target()->is_store_stub()); }
 
-  Object* Store(State state,
-                Handle<Object> object,
+  Object* Store(Handle<Object> object,
                 Handle<String> name,
                 Handle<Object> value);
 
@@ -299,7 +299,7 @@ class StoreIC: public IC {
   // Update the inline cache and the global stub cache based on the
   // lookup result.
   void UpdateCaches(LookupResult* lookup,
-                    State state, Handle<JSObject> receiver,
+                    Handle<JSObject> receiver,
                     Handle<String> name,
                     Handle<Object> value);
 
@@ -320,8 +320,7 @@ class KeyedStoreIC: public IC {
  public:
   KeyedStoreIC() : IC(NO_EXTRA_FRAME) { }
 
-  Object* Store(State state,
-                Handle<Object> object,
+  Object* Store(Handle<Object> object,
                 Handle<Object> name,
                 Handle<Object> value);
 
@@ -335,7 +334,6 @@ class KeyedStoreIC: public IC {
 
   // Update the inline cache.
   void UpdateCaches(LookupResult* lookup,
-                    State state,
                     Handle<JSObject> receiver,
                     Handle<String> name,
                     Handle<Object> value);

src/objects-inl.h

@@ -2109,6 +2109,20 @@ void Map::ClearCodeCache() {
 }
 
 
+Object* Map::FindInCodeCache(String* name, Code::Flags flags) {
+  int index;
+  return FindIndexInCodeCache(name, flags, &index);
+}
+
+
+void Map::RemoveFromCodeCache(int index) {
+  FixedArray* array = code_cache();
+  ASSERT(array->length() >= index && array->get(index)->IsCode());
+  array->set_undefined(index - 1);  // key
+  array->set_undefined(index);  // code
+}
+
+
 #undef CAST_ACCESSOR
 #undef INT_ACCESSORS
 #undef SMI_ACCESSORS

src/objects.cc

@@ -2410,38 +2410,24 @@ Object* Map::UpdateCodeCache(String* name, Code* code) {
 }
 
 
-Object* Map::FindInCodeCache(String* name, Code::Flags flags) {
+Object* Map::FindIndexInCodeCache(String* name, Code::Flags flags, int* index) {
   FixedArray* cache = code_cache();
   int length = cache->length();
   for (int i = 0; i < length; i += 2) {
     Object* key = cache->get(i);
     if (key->IsUndefined()) {
-      return key;
+      continue;
     }
     if (name->Equals(String::cast(key))) {
       Code* code = Code::cast(cache->get(i + 1));
-      if (code->flags() == flags) return code;
+      if (code->flags() == flags) {
+        *index = i + 1;
+        return code;
       }
     }
-  return Heap::undefined_value();
-}
-
-
-int Map::IndexInCodeCache(Code* code) {
-  FixedArray* array = code_cache();
-  int len = array->length();
-  for (int i = 0; i < len; i += 2) {
-    if (array->get(i + 1) == code) return i + 1;
   }
-  return -1;
-}
-
-
-void Map::RemoveFromCodeCache(int index) {
-  FixedArray* array = code_cache();
-  ASSERT(array->length() >= index && array->get(index)->IsCode());
-  array->set_undefined(index - 1);  // key
-  array->set_undefined(index);  // code
+  *index = -1;
+  return Heap::undefined_value();
 }
 
 

src/objects.h

@@ -2342,14 +2342,14 @@ class Map: public HeapObject {
   Object* UpdateCodeCache(String* name, Code* code);
 
   // Returns the found code or undefined if absent.
-  Object* FindInCodeCache(String* name, Code::Flags flags);
+  inline Object* FindInCodeCache(String* name, Code::Flags flags);
 
-  // Returns the non-negative index of the code object if it is in the
-  // cache and -1 otherwise.
-  int IndexInCodeCache(Code* code);
+  // Returns the found code or undefined if absent.  Also returns the
+  // index at which the code was found or -1 if absent.
+  Object* FindIndexInCodeCache(String* name, Code::Flags flags, int* index);
 
   // Removes a code object from the code cache at the given index.
-  void RemoveFromCodeCache(int index);
+  inline void RemoveFromCodeCache(int index);
 
   // Dispatched behavior.
   void MapIterateBody(ObjectVisitor* v);