Cleanup polymorphic IC code to make use of ElementsKind information in maps.

src/ic.cc

 // Copyright 2011 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 1079 matching lines @@
 
     isolate()->stub_cache()->Set(*name, map, Code::cast(code));
   }
 
 #ifdef DEBUG
   TraceIC("LoadIC", name, state, target());
 #endif
 }
 
 
-String* KeyedLoadIC::GetStubNameForCache(IC::State ic_state) {
-  if (ic_state == MONOMORPHIC) {
-    return isolate()->heap()->KeyedLoadElementMonomorphic_symbol();
-  } else {
-    ASSERT(ic_state == MEGAMORPHIC);
-    return isolate()->heap()->KeyedLoadElementPolymorphic_symbol();
-  }
-}
-
-
 MaybeObject* KeyedLoadIC::GetFastElementStubWithoutMapCheck(
     bool is_js_array) {
   return KeyedLoadFastElementStub().TryGetCode();
 }
 
 
 MaybeObject* KeyedLoadIC::GetExternalArrayStubWithoutMapCheck(
     JSObject::ElementsKind elements_kind) {
   return KeyedLoadExternalArrayStub(elements_kind).TryGetCode();
 }
@@ skipping 507 matching lines @@
     }
   }
 }
 
 
 MaybeObject* KeyedIC::ComputeStub(JSObject* receiver,
                                   bool is_store,
                                   StrictModeFlag strict_mode,
                                   Code* generic_stub) {
   State ic_state = target()->ic_state();
-  Code* monomorphic_stub;
-  // Always compute the MONOMORPHIC stub, even if the MEGAMORPHIC stub ends up
-  // being used. This is necessary because the megamorphic stub needs to have
-  // access to more information than what is stored in the receiver map in some
-  // cases (external arrays need the array type from the MONOMORPHIC stub).
-  MaybeObject* maybe_stub = ComputeMonomorphicStub(receiver,
-                                                   is_store,
-                                                   strict_mode,
-                                                   generic_stub);
-  if (!maybe_stub->To(&monomorphic_stub)) return maybe_stub;
+  if (ic_state == UNINITIALIZED || ic_state == PREMONOMORPHIC) {
+    Code* monomorphic_stub;
+    MaybeObject* maybe_stub = ComputeMonomorphicStub(receiver,
+                                                     is_store,
+                                                     strict_mode,
+                                                     generic_stub);
+    if (!maybe_stub->To(&monomorphic_stub)) return maybe_stub;
 
-  if (ic_state == UNINITIALIZED || ic_state == PREMONOMORPHIC) {
     return monomorphic_stub;
   }
   ASSERT(target() != generic_stub);
 
   // Don't handle megamorphic property accesses for INTERCEPTORS or CALLBACKS
   // via megamorphic stubs, since they don't have a map in their relocation info
   // and so the stubs can't be harvested for the object needed for a map check.
   if (target()->type() != NORMAL) {
     return generic_stub;
   }
@@ skipping 30 matching lines @@
   for (int i = 0; i < target_receiver_maps.length(); ++i) {
     Map* receiver_map(target_receiver_maps.at(i));
     MaybeObject* maybe_cached_stub = ComputeMonomorphicStubWithoutMapCheck(
         receiver_map, strict_mode, generic_stub);
     Code* cached_stub;
     if (!maybe_cached_stub->To(&cached_stub)) return maybe_cached_stub;
     handler_ics.Add(cached_stub);
   }
   // Build the MEGAMORPHIC stub.
   Code* stub;
-  maybe_stub = ConstructMegamorphicStub(&target_receiver_maps,
-                                        &handler_ics,
-                                        strict_mode);
+  MaybeObject* maybe_stub = ConstructMegamorphicStub(&target_receiver_maps,
+                                                     &handler_ics,
+                                                     strict_mode);
   if (!maybe_stub->To(&stub)) return maybe_stub;
   MaybeObject* maybe_update = cache->Update(&target_receiver_maps, flags, stub);
   if (maybe_update->IsFailure()) return maybe_update;
   return stub;
 }
 
 
 MaybeObject* KeyedIC::ComputeMonomorphicStubWithoutMapCheck(
     Map* receiver_map,
     StrictModeFlag strict_mode,
     Code* generic_stub) {
   if ((receiver_map->instance_type() & kNotStringTag) == 0) {
     ASSERT(string_stub() != NULL);
     return string_stub();
   } else if (receiver_map->has_external_array_elements()) {
-    // Determine the array type from the default MONOMORPHIC already generated
-    // stub. There is no other way to determine the type of the external array
-    // directly from the receiver type.
-    Code::Kind kind = this->kind();
-    Code::Flags flags = Code::ComputeMonomorphicFlags(kind,
-                                                      NORMAL,
-                                                      strict_mode);
-    String* monomorphic_name = GetStubNameForCache(MONOMORPHIC);
-    Object* maybe_default_stub = receiver_map->FindInCodeCache(monomorphic_name,
-                                                               flags);
-    if (maybe_default_stub->IsUndefined()) {
-      return generic_stub;
-    }
-    Code* default_stub = Code::cast(maybe_default_stub);
-    Map* first_map = default_stub->FindFirstMap();
-    return GetExternalArrayStubWithoutMapCheck(first_map->elements_kind());
+    return GetExternalArrayStubWithoutMapCheck(receiver_map->elements_kind());
   } else if (receiver_map->has_fast_elements()) {
     bool is_js_array = receiver_map->instance_type() == JS_ARRAY_TYPE;
     return GetFastElementStubWithoutMapCheck(is_js_array);
   } else {
     return generic_stub;
   }
 }
 
 
 MaybeObject* KeyedIC::ComputeMonomorphicStub(JSObject* receiver,
                                              bool is_store,
                                              StrictModeFlag strict_mode,
                                              Code* generic_stub) {
   Code* result = NULL;
   if (receiver->HasFastElements() ||
       receiver->HasExternalArrayElements() ||
       receiver->HasDictionaryElements()) {
     MaybeObject* maybe_stub =
         isolate()->stub_cache()->ComputeKeyedLoadOrStoreElement(
             receiver, is_store, strict_mode);
     if (!maybe_stub->To(&result)) return maybe_stub;
   } else {
     result = generic_stub;
   }
   return result;
 }
 
 
-String* KeyedStoreIC::GetStubNameForCache(IC::State ic_state) {
-  if (ic_state == MONOMORPHIC) {
-    return isolate()->heap()->KeyedStoreElementMonomorphic_symbol();
-  } else {
-    ASSERT(ic_state == MEGAMORPHIC);
-    return isolate()->heap()->KeyedStoreElementPolymorphic_symbol();
-  }
-}
-
-
 MaybeObject* KeyedStoreIC::GetFastElementStubWithoutMapCheck(
     bool is_js_array) {
   return KeyedStoreFastElementStub(is_js_array).TryGetCode();
 }
 
 
 MaybeObject* KeyedStoreIC::GetExternalArrayStubWithoutMapCheck(
     JSObject::ElementsKind elements_kind) {
   return KeyedStoreExternalArrayStub(elements_kind).TryGetCode();
 }
@@ skipping 779 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal