diff options
Diffstat (limited to 'runtime/lambda/box_table.h')
| -rw-r--r-- | runtime/lambda/box_table.h | 146 |
1 files changed, 0 insertions, 146 deletions
diff --git a/runtime/lambda/box_table.h b/runtime/lambda/box_table.h deleted file mode 100644 index adb733271e..0000000000 --- a/runtime/lambda/box_table.h +++ /dev/null @@ -1,146 +0,0 @@ -/* - * Copyright (C) 2015 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_LAMBDA_BOX_TABLE_H_ -#define ART_RUNTIME_LAMBDA_BOX_TABLE_H_ - -#include "base/allocator.h" -#include "base/hash_map.h" -#include "gc_root.h" -#include "base/macros.h" -#include "base/mutex.h" -#include "object_callbacks.h" - -#include <stdint.h> - -namespace art { - -class ArtMethod; // forward declaration - -namespace mirror { -class Object; // forward declaration -} // namespace mirror - -namespace lambda { -struct Closure; // forward declaration - -/* - * Store a table of boxed lambdas. This is required to maintain object referential equality - * when a lambda is re-boxed. - * - * Conceptually, we store a mapping of Closures -> Weak Reference<Boxed Lambda Object>. - * When too many objects get GCd, we shrink the underlying table to use less space. - */ -class BoxTable FINAL { - public: - using ClosureType = art::lambda::Closure*; - - // Boxes a closure into an object. Returns null and throws an exception on failure. - mirror::Object* BoxLambda(const ClosureType& closure) - SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(!Locks::lambda_table_lock_); - - // Unboxes an object back into the lambda. Returns false and throws an exception on failure. - bool UnboxLambda(mirror::Object* object, ClosureType* out_closure) - SHARED_REQUIRES(Locks::mutator_lock_); - - // Sweep weak references to lambda boxes. Update the addresses if the objects have been - // moved, and delete them from the table if the objects have been cleaned up. - void SweepWeakBoxedLambdas(IsMarkedVisitor* visitor) - SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(!Locks::lambda_table_lock_); - - // GC callback: Temporarily block anyone from touching the map. - void DisallowNewWeakBoxedLambdas() - REQUIRES(!Locks::lambda_table_lock_); - - // GC callback: Unblock any readers who have been queued waiting to touch the map. - void AllowNewWeakBoxedLambdas() - REQUIRES(!Locks::lambda_table_lock_); - - // GC callback: Unblock any readers who have been queued waiting to touch the map. - void BroadcastForNewWeakBoxedLambdas() - REQUIRES(!Locks::lambda_table_lock_); - - BoxTable(); - ~BoxTable(); - - private: - // Explanation: - // - After all threads are suspended (exclusive mutator lock), - // the concurrent-copying GC can move objects from the "from" space to the "to" space. - // If an object is moved at that time and *before* SweepSystemWeaks are called then - // we don't know if the move has happened yet. - // Successive reads will then (incorrectly) look at the objects in the "from" space, - // which is a problem since the objects have been already forwarded and mutations - // would not be visible in the right space. - // Instead, use a GcRoot here which will be automatically updated by the GC. - // - // Also, any reads should be protected by a read barrier to always give us the "to" space address. - using ValueType = GcRoot<mirror::Object>; - - // Attempt to look up the lambda in the map, or return null if it's not there yet. - ValueType FindBoxedLambda(const ClosureType& closure) const - SHARED_REQUIRES(Locks::lambda_table_lock_); - - // If the GC has come in and temporarily disallowed touching weaks, block until is it allowed. - void BlockUntilWeaksAllowed() - SHARED_REQUIRES(Locks::lambda_table_lock_); - - // Wrap the Closure into a unique_ptr so that the HashMap can delete its memory automatically. - using UnorderedMapKeyType = ClosureType; - - // EmptyFn implementation for art::HashMap - struct EmptyFn { - void MakeEmpty(std::pair<UnorderedMapKeyType, ValueType>& item) const - NO_THREAD_SAFETY_ANALYSIS; // SHARED_REQUIRES(Locks::mutator_lock_) - - bool IsEmpty(const std::pair<UnorderedMapKeyType, ValueType>& item) const; - }; - - // HashFn implementation for art::HashMap - struct HashFn { - size_t operator()(const UnorderedMapKeyType& key) const - NO_THREAD_SAFETY_ANALYSIS; // SHARED_REQUIRES(Locks::mutator_lock_) - }; - - // EqualsFn implementation for art::HashMap - struct EqualsFn { - bool operator()(const UnorderedMapKeyType& lhs, const UnorderedMapKeyType& rhs) const - NO_THREAD_SAFETY_ANALYSIS; // SHARED_REQUIRES(Locks::mutator_lock_) - }; - - using UnorderedMap = art::HashMap<UnorderedMapKeyType, - ValueType, - EmptyFn, - HashFn, - EqualsFn, - TrackingAllocator<std::pair<ClosureType, ValueType>, - kAllocatorTagLambdaBoxTable>>; - - UnorderedMap map_ GUARDED_BY(Locks::lambda_table_lock_); - bool allow_new_weaks_ GUARDED_BY(Locks::lambda_table_lock_); - ConditionVariable new_weaks_condition_ GUARDED_BY(Locks::lambda_table_lock_); - - // Shrink the map when we get below this load factor. - // (This is an arbitrary value that should be large enough to prevent aggressive map erases - // from shrinking the table too often.) - static constexpr double kMinimumLoadFactor = UnorderedMap::kDefaultMinLoadFactor / 2; - - DISALLOW_COPY_AND_ASSIGN(BoxTable); -}; - -} // namespace lambda -} // namespace art - -#endif // ART_RUNTIME_LAMBDA_BOX_TABLE_H_ |