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1 /*
2  * Copyright (c) 2025 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef ECMASCRIPT_ENUM_CACHE_H
17 #define ECMASCRIPT_ENUM_CACHE_H
18 
19 #include "ecmascript/ecma_macros.h"
20 #include "ecmascript/mem/barriers.h"
21 
22 // EnumCacheKind is only used in for-in.
23 enum class EnumCacheKind : uint8_t {
24     NONE,          // No Cache, go slow path
25     SIMPLE,        // Simple enum cache
26     PROTOCHAIN,    // Prototype chain info enum cache
27 };
28 
29 // +---------------+-------------------------------------------+-------------------------------------------------+
30 // | EnumCacheKind | Status Description                        | Valid Conditions                                |
31 // +---------------+-------------------------------------------+-------------------------------------------------+
32 // | None          | - Uninitialized or in SlowPath mode.      | - None (No additional conditions required)      |
33 // |               |   No active cache optimization.           |                                                 |
34 // +---------------+-------------------------------------------+-------------------------------------------------+
35 // | SIMPLE        | - Fast path for simple enum cache check.  | - Receiver's proto is NOT a HeapObject,         |
36 // |               |   Indicates:                              |   OR                                            |
37 // |               |   • Properties exist ONLY on the object   | - Receiver.proto.ProtoChainInfoEnumCache ==     |
38 // |               |   itself (no prototype chain properties)  |   Undefined. (Ensure no keys on prototype chain)|
39 // |               |   • NO elements (indexed properties) on   |                                                 |
40 // |               |     self/proto                            |                                                 |
41 // +---------------+-------------------------------------------+-------------------------------------------------+
42 // | PROTOCHAIN    | - Fast path for protochain enum cache.    | - Receiver's proto is a HeapObject, AND         |
43 // |               |   Indicates:                              | - Receiver.ProtoChainInfoEnumCache ==           |
44 // |               |   • Properties exist on the object itself |   receiver.proto.EnumCacheAll (Cache matches    |
45 // |               |   or prototype chain                      |   prototype's full enum cache), AND             |
46 // |               |   • NO elements (indexed properties) on   | - Receiver.ProtoChainInfoEnumCache != Null      |
47 // |               |     self/proto                            |   (Valid cache exists).                         |
48 // +---------------+-------------------------------------------+-------------------------------------------------+
49 
50 namespace panda {
51 namespace ecmascript {
52 class EnumCache : public TaggedObject {
53 public:
54     CAST_CHECK(EnumCache, IsEnumCache);
55 
56     static constexpr size_t ENUM_CACHE_OWN_OFFSET = TaggedObjectSize();
57 
CheckSelfAndProtoEnumCache(const JSThread * thread,JSTaggedValue enumCacheOwn,JSTaggedValue enumCacheProto)58     static bool CheckSelfAndProtoEnumCache(const JSThread *thread, JSTaggedValue enumCacheOwn,
59         JSTaggedValue enumCacheProto)
60     {
61         if (!enumCacheOwn.IsEnumCache() || !enumCacheProto.IsEnumCache()) {
62             return false;
63         }
64         auto keyOwn =  EnumCache::Cast(enumCacheOwn.GetTaggedObject())->GetProtoChainInfoEnumCache(thread);
65         auto keyProto = EnumCache::Cast(enumCacheProto.GetTaggedObject())->GetEnumCacheAll(thread);
66         if (keyOwn != keyProto || keyOwn == JSTaggedValue::Null()) {
67             return false;
68         }
69         return true;
70     }
71 
IsEnumCacheAllValid(const JSThread * thread)72     inline bool IsEnumCacheAllValid(const JSThread *thread) const
73     {
74         return GetEnumCacheAll(thread) != JSTaggedValue::Null();
75     }
76 
IsEnumCacheOwnValid(const JSThread * thread)77     inline bool IsEnumCacheOwnValid(const JSThread *thread) const
78     {
79         return GetEnumCacheOwn(thread) != JSTaggedValue::Null();
80     }
81 
IsEnumCacheProtoInfoUndefined(const JSThread * thread)82     inline bool IsEnumCacheProtoInfoUndefined(const JSThread *thread) const
83     {
84         return GetProtoChainInfoEnumCache(thread) == JSTaggedValue::Undefined();
85     }
86 
SetInvalidState(const JSThread * thread)87     inline void SetInvalidState(const JSThread *thread)
88     {
89         SetEnumCacheAll(thread, JSTaggedValue::Null());
90         SetProtoChainInfoEnumCache(thread, JSTaggedValue::Null());
91     }
92 
93     // EnumCacheOwn holds enum keys on itself.
94     ACCESSORS(EnumCacheOwn, ENUM_CACHE_OWN_OFFSET, ENUM_CACHE_ALL_OFFSET);
95 
96     // EnumCacheAll holds all enum keys on the prototype chain, including its own keys.
97     ACCESSORS(EnumCacheAll, ENUM_CACHE_ALL_OFFSET, PROTO_CHAIN_INFO_ENUM_CACHE_OFFSET);
98 
99     // ProtoChainInfoEnumCache holds all enum keys on the prototype chain, excluding its own keys.
100     ACCESSORS(ProtoChainInfoEnumCache, PROTO_CHAIN_INFO_ENUM_CACHE_OFFSET, ENUM_CACHE_KIND_OFFSET);
101     ACCESSORS_PRIMITIVE_FIELD(EnumCacheKind, uint32_t, ENUM_CACHE_KIND_OFFSET, LAST_OFFSET);
102 
103     DEFINE_ALIGN_SIZE(LAST_OFFSET);
104 
105     DECL_VISIT_OBJECT(ENUM_CACHE_OWN_OFFSET, ENUM_CACHE_KIND_OFFSET)
106 
107     DECL_DUMP()
108 };
109 }  // namespace ecmascript
110 }  // namespace panda
111 
112 #endif  // ECMASCRIPT_IC_ENUM_CACHE_H
113