| /* |
| * Copyright (C) 2011 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef ART_RUNTIME_INTERN_TABLE_H_ |
| #define ART_RUNTIME_INTERN_TABLE_H_ |
| |
| #include <unordered_set> |
| |
| #include "base/allocator.h" |
| #include "base/hash_set.h" |
| #include "base/mutex.h" |
| #include "gc_root.h" |
| #include "object_callbacks.h" |
| |
| namespace art { |
| |
| namespace gc { |
| namespace space { |
| class ImageSpace; |
| } // namespace space |
| } // namespace gc |
| |
| enum VisitRootFlags : uint8_t; |
| |
| namespace mirror { |
| class String; |
| } // namespace mirror |
| class Transaction; |
| |
| /** |
| * Used to intern strings. |
| * |
| * There are actually two tables: one that holds strong references to its strings, and one that |
| * holds weak references. The former is used for string literals, for which there is an effective |
| * reference from the constant pool. The latter is used for strings interned at runtime via |
| * String.intern. Some code (XML parsers being a prime example) relies on being able to intern |
| * arbitrarily many strings for the duration of a parse without permanently increasing the memory |
| * footprint. |
| */ |
| class InternTable { |
| public: |
| InternTable(); |
| |
| // Interns a potentially new string in the 'strong' table. (See above.) |
| mirror::String* InternStrong(int32_t utf16_length, const char* utf8_data) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| // Interns a potentially new string in the 'strong' table. (See above.) |
| mirror::String* InternStrong(const char* utf8_data) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| // Interns a potentially new string in the 'strong' table. (See above.) |
| mirror::String* InternStrong(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| // Interns a potentially new string in the 'weak' table. (See above.) |
| mirror::String* InternWeak(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| void SweepInternTableWeaks(IsMarkedCallback* callback, void* arg) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| bool ContainsWeak(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| // Total number of interned strings. |
| size_t Size() const LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| // Total number of weakly live interned strings. |
| size_t StrongSize() const LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| // Total number of strongly live interned strings. |
| size_t WeakSize() const LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| |
| void VisitRoots(RootVisitor* visitor, VisitRootFlags flags) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| void DumpForSigQuit(std::ostream& os) const; |
| |
| void DisallowNewInterns() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| void AllowNewInterns() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| void EnsureNewInternsDisallowed() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| // Adds all of the resolved image strings from the image space into the intern table. The |
| // advantage of doing this is preventing expensive DexFile::FindStringId calls. |
| void AddImageStringsToTable(gc::space::ImageSpace* image_space) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| // Copy the post zygote tables to pre zygote to save memory by preventing dirty pages. |
| void SwapPostZygoteWithPreZygote() |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| |
| // Add an intern table which was serialized to the image. |
| void AddImageInternTable(gc::space::ImageSpace* image_space) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| |
| // Read the intern table from memory. The elements aren't copied, the intern hash set data will |
| // point to somewhere within ptr. Only reads the strong interns. |
| size_t ReadFromMemory(const uint8_t* ptr) LOCKS_EXCLUDED(Locks::intern_table_lock_) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| // Write the post zygote intern table to a pointer. Only writes the strong interns since it is |
| // expected that there is no weak interns since this is called from the image writer. |
| size_t WriteToMemory(uint8_t* ptr) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| LOCKS_EXCLUDED(Locks::intern_table_lock_); |
| |
| private: |
| class StringHashEquals { |
| public: |
| std::size_t operator()(const GcRoot<mirror::String>& root) const NO_THREAD_SAFETY_ANALYSIS; |
| bool operator()(const GcRoot<mirror::String>& a, const GcRoot<mirror::String>& b) const |
| NO_THREAD_SAFETY_ANALYSIS; |
| }; |
| class GcRootEmptyFn { |
| public: |
| void MakeEmpty(GcRoot<mirror::String>& item) const { |
| item = GcRoot<mirror::String>(); |
| } |
| bool IsEmpty(const GcRoot<mirror::String>& item) const { |
| return item.IsNull(); |
| } |
| }; |
| |
| // Table which holds pre zygote and post zygote interned strings. There is one instance for |
| // weak interns and strong interns. |
| class Table { |
| public: |
| mirror::String* Find(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void Insert(mirror::String* s) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void Remove(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void VisitRoots(RootVisitor* visitor) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void SweepWeaks(IsMarkedCallback* callback, void* arg) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void SwapPostZygoteWithPreZygote() EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| size_t Size() const EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| // Read pre zygote table is called from ReadFromMemory which happens during runtime creation |
| // when we load the image intern table. Returns how many bytes were read. |
| size_t ReadIntoPreZygoteTable(const uint8_t* ptr) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| // The image writer calls WritePostZygoteTable through WriteToMemory, it writes the interns in |
| // the post zygote table. Returns how many bytes were written. |
| size_t WriteFromPostZygoteTable(uint8_t* ptr) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| private: |
| typedef HashSet<GcRoot<mirror::String>, GcRootEmptyFn, StringHashEquals, StringHashEquals, |
| TrackingAllocator<GcRoot<mirror::String>, kAllocatorTagInternTable>> UnorderedSet; |
| |
| void SweepWeaks(UnorderedSet* set, IsMarkedCallback* callback, void* arg) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| |
| // We call SwapPostZygoteWithPreZygote when we create the zygote to reduce private dirty pages |
| // caused by modifying the zygote intern table hash table. The pre zygote table are the |
| // interned strings which were interned before we created the zygote space. Post zygote is self |
| // explanatory. |
| UnorderedSet pre_zygote_table_; |
| UnorderedSet post_zygote_table_; |
| }; |
| |
| // Insert if non null, otherwise return null. |
| mirror::String* Insert(mirror::String* s, bool is_strong) |
| LOCKS_EXCLUDED(Locks::intern_table_lock_) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| mirror::String* LookupStrong(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| mirror::String* LookupWeak(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| mirror::String* InsertStrong(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| mirror::String* InsertWeak(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void RemoveStrong(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void RemoveWeak(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| |
| // Transaction rollback access. |
| mirror::String* LookupStringFromImage(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| mirror::String* InsertStrongFromTransaction(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| mirror::String* InsertWeakFromTransaction(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void RemoveStrongFromTransaction(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| void RemoveWeakFromTransaction(mirror::String* s) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_); |
| friend class Transaction; |
| |
| size_t ReadFromMemoryLocked(const uint8_t* ptr) |
| EXCLUSIVE_LOCKS_REQUIRED(Locks::intern_table_lock_) |
| SHARED_LOCKS_REQUIRED(Locks::mutator_lock_); |
| |
| bool image_added_to_intern_table_ GUARDED_BY(Locks::intern_table_lock_); |
| bool log_new_roots_ GUARDED_BY(Locks::intern_table_lock_); |
| bool allow_new_interns_ GUARDED_BY(Locks::intern_table_lock_); |
| ConditionVariable new_intern_condition_ GUARDED_BY(Locks::intern_table_lock_); |
| // Since this contains (strong) roots, they need a read barrier to |
| // enable concurrent intern table (strong) root scan. Do not |
| // directly access the strings in it. Use functions that contain |
| // read barriers. |
| Table strong_interns_ GUARDED_BY(Locks::intern_table_lock_); |
| std::vector<GcRoot<mirror::String>> new_strong_intern_roots_ |
| GUARDED_BY(Locks::intern_table_lock_); |
| // Since this contains (weak) roots, they need a read barrier. Do |
| // not directly access the strings in it. Use functions that contain |
| // read barriers. |
| Table weak_interns_ GUARDED_BY(Locks::intern_table_lock_); |
| }; |
| |
| } // namespace art |
| |
| #endif // ART_RUNTIME_INTERN_TABLE_H_ |