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// Copyright 2017 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef V8_OBJECTS_COMPILATION_CACHE_TABLE_H_ #define V8_OBJECTS_COMPILATION_CACHE_TABLE_H_ #include "src/objects/feedback-cell.h" #include "src/objects/hash-table.h" #include "src/objects/js-regexp.h" #include "src/objects/shared-function-info.h" #include "src/roots/roots.h" // Has to be the last include (doesn't have include guards): #include "src/objects/object-macros.h" namespace v8 { namespace internal { class CompilationCacheShape : public BaseShape<HashTableKey*> { public: static inline bool IsMatch(HashTableKey* key, Object value) { return key->IsMatch(value); } static inline uint32_t Hash(ReadOnlyRoots roots, HashTableKey* key) { return key->Hash(); } static inline uint32_t RegExpHash(String string, Smi flags); static inline uint32_t StringSharedHash(String source, SharedFunctionInfo shared, LanguageMode language_mode, int position); static inline uint32_t StringSharedHash(String source, LanguageMode language_mode); static inline uint32_t HashForObject(ReadOnlyRoots roots, Object object); static const int kPrefixSize = 0; // An 'entry' is essentially a grouped collection of slots. Entries are used // in various ways by the different caches; most store the actual key in the // first entry slot, but it may also be used differently. // Why 3 slots? Because of the eval cache. static const int kEntrySize = 3; static const bool kMatchNeedsHoleCheck = true; }; class InfoCellPair { public: InfoCellPair() = default; inline InfoCellPair(Isolate* isolate, SharedFunctionInfo shared, FeedbackCell feedback_cell); FeedbackCell feedback_cell() const { DCHECK(is_compiled_scope_.is_compiled()); return feedback_cell_; } SharedFunctionInfo shared() const { DCHECK(is_compiled_scope_.is_compiled()); return shared_; } bool has_feedback_cell() const { return !feedback_cell_.is_null() && is_compiled_scope_.is_compiled(); } bool has_shared() const { // Only return true if SFI is compiled - the bytecode could have been // flushed while it's in the compilation cache, and not yet have been // removed form the compilation cache. return !shared_.is_null() && is_compiled_scope_.is_compiled(); } private: IsCompiledScope is_compiled_scope_; SharedFunctionInfo shared_; FeedbackCell feedback_cell_; }; EXTERN_DECLARE_HASH_TABLE(CompilationCacheTable, CompilationCacheShape) class CompilationCacheTable : public HashTable<CompilationCacheTable, CompilationCacheShape> { public: NEVER_READ_ONLY_SPACE // The 'script' cache contains SharedFunctionInfos. static MaybeHandle<SharedFunctionInfo> LookupScript( Handle<CompilationCacheTable> table, Handle<String> src, LanguageMode language_mode, Isolate* isolate); static Handle<CompilationCacheTable> PutScript( Handle<CompilationCacheTable> cache, Handle<String> src, LanguageMode language_mode, Handle<SharedFunctionInfo> value, Isolate* isolate); // Eval code only gets cached after a second probe for the // code object. To do so, on first "put" only a hash identifying the // source is entered into the cache, mapping it to a lifetime count of // the hash. On each call to Age all such lifetimes get reduced, and // removed once they reach zero. If a second put is called while such // a hash is live in the cache, the hash gets replaced by an actual // cache entry. Age also removes stale live entries from the cache. // Such entries are identified by SharedFunctionInfos pointing to // either the recompilation stub, or to "old" code. This avoids memory // leaks due to premature caching of eval strings that are // never needed later. static InfoCellPair LookupEval(Handle<CompilationCacheTable> table, Handle<String> src, Handle<SharedFunctionInfo> shared, Handle<Context> native_context, LanguageMode language_mode, int position); static Handle<CompilationCacheTable> PutEval( Handle<CompilationCacheTable> cache, Handle<String> src, Handle<SharedFunctionInfo> outer_info, Handle<SharedFunctionInfo> value, Handle<Context> native_context, Handle<FeedbackCell> feedback_cell, int position); // The RegExp cache contains JSRegExp::data fixed arrays. Handle<Object> LookupRegExp(Handle<String> source, JSRegExp::Flags flags); static Handle<CompilationCacheTable> PutRegExp( Isolate* isolate, Handle<CompilationCacheTable> cache, Handle<String> src, JSRegExp::Flags flags, Handle<FixedArray> value); void Remove(Object value); void Age(Isolate* isolate); DECL_CAST(CompilationCacheTable) private: void RemoveEntry(int entry_index); OBJECT_CONSTRUCTORS(CompilationCacheTable, HashTable<CompilationCacheTable, CompilationCacheShape>); }; } // namespace internal } // namespace v8 #include "src/objects/object-macros-undef.h" #endif // V8_OBJECTS_COMPILATION_CACHE_TABLE_H_