Create AllocationSite objects, pointed to by AllocationSiteInfo.

src/objects.h

 // 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 363 matching lines @@
   V(EXECUTABLE_ACCESSOR_INFO_TYPE)                                             \
   V(ACCESSOR_PAIR_TYPE)                                                        \
   V(ACCESS_CHECK_INFO_TYPE)                                                    \
   V(INTERCEPTOR_INFO_TYPE)                                                     \
   V(CALL_HANDLER_INFO_TYPE)                                                    \
   V(FUNCTION_TEMPLATE_INFO_TYPE)                                               \
   V(OBJECT_TEMPLATE_INFO_TYPE)                                                 \
   V(SIGNATURE_INFO_TYPE)                                                       \
   V(TYPE_SWITCH_INFO_TYPE)                                                     \
   V(ALLOCATION_SITE_INFO_TYPE)                                                 \
+  V(ALLOCATION_SITE_TYPE)                                                      \
   V(SCRIPT_TYPE)                                                               \
   V(CODE_CACHE_TYPE)                                                           \
   V(POLYMORPHIC_CODE_CACHE_TYPE)                                               \
   V(TYPE_FEEDBACK_INFO_TYPE)                                                   \
   V(ALIASED_ARGUMENTS_ENTRY_TYPE)                                              \
                                                                                \
   V(FIXED_ARRAY_TYPE)                                                          \
   V(FIXED_DOUBLE_ARRAY_TYPE)                                                   \
   V(SHARED_FUNCTION_INFO_TYPE)                                                 \
                                                                                \
@@ skipping 142 matching lines @@
   V(EXECUTABLE_ACCESSOR_INFO, ExecutableAccessorInfo, executable_accessor_info)\
   V(ACCESSOR_PAIR, AccessorPair, accessor_pair)                                \
   V(ACCESS_CHECK_INFO, AccessCheckInfo, access_check_info)                     \
   V(INTERCEPTOR_INFO, InterceptorInfo, interceptor_info)                       \
   V(CALL_HANDLER_INFO, CallHandlerInfo, call_handler_info)                     \
   V(FUNCTION_TEMPLATE_INFO, FunctionTemplateInfo, function_template_info)      \
   V(OBJECT_TEMPLATE_INFO, ObjectTemplateInfo, object_template_info)            \
   V(SIGNATURE_INFO, SignatureInfo, signature_info)                             \
   V(TYPE_SWITCH_INFO, TypeSwitchInfo, type_switch_info)                        \
   V(SCRIPT, Script, script)                                                    \
+  V(ALLOCATION_SITE, AllocationSite, allocation_site)                          \
   V(ALLOCATION_SITE_INFO, AllocationSiteInfo, allocation_site_info)            \
   V(CODE_CACHE, CodeCache, code_cache)                                         \
   V(POLYMORPHIC_CODE_CACHE, PolymorphicCodeCache, polymorphic_code_cache)      \
   V(TYPE_FEEDBACK_INFO, TypeFeedbackInfo, type_feedback_info)                  \
   V(ALIASED_ARGUMENTS_ENTRY, AliasedArgumentsEntry, aliased_arguments_entry)
 
 #ifdef ENABLE_DEBUGGER_SUPPORT
 #define STRUCT_LIST_DEBUGGER(V)                                                \
   V(DEBUG_INFO, DebugInfo, debug_info)                                         \
   V(BREAK_POINT_INFO, BreakPointInfo, break_point_info)
@@ skipping 139 matching lines @@
   DECLARED_ACCESSOR_INFO_TYPE,
   EXECUTABLE_ACCESSOR_INFO_TYPE,
   ACCESSOR_PAIR_TYPE,
   ACCESS_CHECK_INFO_TYPE,
   INTERCEPTOR_INFO_TYPE,
   CALL_HANDLER_INFO_TYPE,
   FUNCTION_TEMPLATE_INFO_TYPE,
   OBJECT_TEMPLATE_INFO_TYPE,
   SIGNATURE_INFO_TYPE,
   TYPE_SWITCH_INFO_TYPE,
+  ALLOCATION_SITE_TYPE,
   ALLOCATION_SITE_INFO_TYPE,
   SCRIPT_TYPE,
   CODE_CACHE_TYPE,
   POLYMORPHIC_CODE_CACHE_TYPE,
   TYPE_FEEDBACK_INFO_TYPE,
   ALIASED_ARGUMENTS_ENTRY_TYPE,
   // The following two instance types are only used when ENABLE_DEBUGGER_SUPPORT
   // is defined. However as include/v8.h contain some of the instance type
   // constants always having them avoids them getting different numbers
   // depending on whether ENABLE_DEBUGGER_SUPPORT is defined or not.
@@ skipping 1484 matching lines @@
   inline MUST_USE_RESULT MaybeObject* GetElementsTransitionMap(
       Isolate* isolate,
       ElementsKind elements_kind);
   MUST_USE_RESULT MaybeObject* GetElementsTransitionMapSlow(
       ElementsKind elements_kind);
 
   static Handle<Object> TransitionElementsKind(Handle<JSObject> object,
                                                ElementsKind to_kind);
 
   MUST_USE_RESULT MaybeObject* TransitionElementsKind(ElementsKind to_kind);
-  MUST_USE_RESULT MaybeObject* UpdateAllocationSiteInfo(
-      ElementsKind to_kind);
+  MUST_USE_RESULT MaybeObject* UpdateAllocationSite(ElementsKind to_kind);
 
   // Replaces an existing transition with a transition to a map with a FIELD.
   MUST_USE_RESULT MaybeObject* ConvertTransitionToMapTransition(
       int transition_index,
       Name* name,
       Object* new_value,
       PropertyAttributes attributes);
 
   // Converts a descriptor of any other type to a real field, backed by the
   // properties array.
@@ skipping 5227 matching lines @@
 };
 
 
 enum AllocationSiteMode {
   DONT_TRACK_ALLOCATION_SITE,
   TRACK_ALLOCATION_SITE,
   LAST_ALLOCATION_SITE_MODE = TRACK_ALLOCATION_SITE
 };
 
 
+class AllocationSite: public Struct {
+ public:
+  DECL_ACCESSORS(payload, Object)

[Hannes Payer (out of office), 2013/06/25 16:35:07]

Can we rename payload to something more meaningful? Like transition_data...?

[mvstanton, 2013/07/02 13:55:11]

For this one I added a TODO because I'd have to touch a lot. I'd like to do it
in the follow up CL which renames AllocationSiteInfo to be called
AllocationMemento. That will be very simple, even though it touches a lot.

+
+  static inline AllocationSite* cast(Object* obj);
+
+  void Initialize() {
+    set_payload(Smi::FromInt(GetInitialFastElementsKind()));

[Hannes Payer (out of office), 2013/06/25 16:35:07]

You can call SetElementsKindPayload there.

[mvstanton, 2013/07/02 13:55:11]

Done.

+  }

[Hannes Payer (out of office), 2013/06/25 16:35:07]

declaration order: Typedefs and Enums, Constants (static const data members),
Constructors, Destructor, Methods including static methods,
Data Members (except static const data members)

Moreover can we keep the static methods together?

[mvstanton, 2013/07/02 13:55:11]

I think I've arranged it better now, have a look.

+
+  DECLARE_PRINTER(AllocationSite)
+  DECLARE_VERIFIER(AllocationSite)
+
+  static inline AllocationSiteMode GetMode(
+      ElementsKind boilerplate_elements_kind);
+  static inline AllocationSiteMode GetMode(ElementsKind from, ElementsKind to);
+
+  static const int kPayloadOffset = HeapObject::kHeaderSize;
+  static const int kSize = kPayloadOffset + kPointerSize;
+  static const uint32_t kMaximumArrayBytesToPretransition = 8 * 1024;
+
+  ElementsKind GetElementsKindPayload() {
+    ASSERT(!IsLiteralSite());
+    return static_cast<ElementsKind>(Smi::cast(payload())->value());
+  }
+
+  void SetElementsKindPayload(ElementsKind kind) {
+    set_payload(Smi::FromInt(static_cast<int>(kind)));
+  }
+
+  bool IsLiteralSite() {
+    return !payload()->IsSmi();  // payload is a boilerplate

[Hannes Payer (out of office), 2013/06/25 16:35:07]

remove comment or make it clear.

[mvstanton, 2013/07/02 13:55:11]

Clarified, and made the test stronger: return payload()->IsJSArray().

+  }
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(AllocationSite);
+};
+
+
 class AllocationSiteInfo: public Struct {

[Hannes Payer (out of office), 2013/06/25 16:35:07]

declaration order... I just saw that it is not consistent in our code base but
the google coding style guide suggest to do that. Let's be a good example.

[mvstanton, 2013/07/02 13:55:11]

Done.

  public:
   DECL_ACCESSORS(payload, Object)
 
   static inline AllocationSiteInfo* cast(Object* obj);
 
   DECLARE_PRINTER(AllocationSiteInfo)
   DECLARE_VERIFIER(AllocationSiteInfo)
 
   // Returns NULL if no AllocationSiteInfo is available for object.
   static AllocationSiteInfo* FindForJSObject(JSObject* object);
-  static inline AllocationSiteMode GetMode(
-      ElementsKind boilerplate_elements_kind);
-  static inline AllocationSiteMode GetMode(ElementsKind from, ElementsKind to);
 
   static const int kPayloadOffset = HeapObject::kHeaderSize;

[Hannes Payer (out of office), 2013/06/25 16:35:07]

Do you think it makes sense to rename kPayloadOffset to kAllocationSiteOffset? I
do not think that we are going to add more fields to AllocationSiteInfo.

[mvstanton, 2013/07/02 13:55:11]

Done.

   static const int kSize = kPayloadOffset + kPointerSize;
-  static const uint32_t kMaximumArrayBytesToPretransition = 8 * 1024;
 
-  bool GetElementsKindPayload(ElementsKind* kind);
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AllocationSiteInfo);
 };
 
 
 // Representation of a slow alias as part of a non-strict arguments objects.
 // For fast aliases (if HasNonStrictArgumentsElements()):
 // - the parameter map contains an index into the context
 // - all attributes of the element have default values
 // For slow aliases (if HasDictionaryArgumentsElements()):
@@ skipping 2169 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_