121 lines
4.1 KiB
C++
121 lines
4.1 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ART_RUNTIME_LINEAR_ALLOC_H_
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#define ART_RUNTIME_LINEAR_ALLOC_H_
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#include "base/arena_allocator.h"
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#include "base/casts.h"
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#include "base/mutex.h"
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namespace art {
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class ArenaPool;
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enum class LinearAllocKind : uint32_t {
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kNoGCRoots = 0, // No GC-root kind should always be 0.
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kGCRootArray,
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kArtMethodArray,
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kArtFieldArray,
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kDexCacheArray,
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kArtMethod
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};
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// Header for every allocation in LinearAlloc. The header provides the type
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// and size information to the GC for invoking the right visitor.
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class TrackingHeader final {
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public:
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static constexpr uint32_t kIs16Aligned = 1;
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TrackingHeader(size_t size, LinearAllocKind kind, bool is_16_aligned = false)
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: kind_(kind), size_(dchecked_integral_cast<uint32_t>(size)) {
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// We need the last bit to store 16-byte alignment flag.
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CHECK_EQ(size_ & kIs16Aligned, 0u);
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if (is_16_aligned) {
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size_ |= kIs16Aligned;
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}
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}
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LinearAllocKind GetKind() const { return kind_; }
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// Since we are linearly allocating and hop from one object to the next during
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// visits, reading 'size_ == 0' indicates that there are no more objects to
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// visit in the given page. But ASAN detects it as use-after-poison access.
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ATTRIBUTE_NO_SANITIZE_ADDRESS size_t GetSize() const { return size_ & ~kIs16Aligned; }
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bool Is16Aligned() const { return size_ & kIs16Aligned; }
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private:
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LinearAllocKind kind_;
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uint32_t size_;
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DISALLOW_IMPLICIT_CONSTRUCTORS(TrackingHeader);
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};
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std::ostream& operator<<(std::ostream& os, LinearAllocKind value);
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class LinearAlloc {
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public:
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static constexpr size_t kAlignment = 8u;
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static_assert(kAlignment >= ArenaAllocator::kAlignment);
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static_assert(sizeof(TrackingHeader) == ArenaAllocator::kAlignment);
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explicit LinearAlloc(ArenaPool* pool, bool track_allocs)
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: lock_("linear alloc"), allocator_(pool), track_allocations_(track_allocs) {}
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void* Alloc(Thread* self, size_t size, LinearAllocKind kind) REQUIRES(!lock_);
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void* AllocAlign16(Thread* self, size_t size, LinearAllocKind kind) REQUIRES(!lock_);
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// Realloc never frees the input pointer, it is the caller's job to do this if necessary.
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void* Realloc(Thread* self, void* ptr, size_t old_size, size_t new_size, LinearAllocKind kind)
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REQUIRES(!lock_);
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// Allocate an array of structs of type T.
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template<class T>
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T* AllocArray(Thread* self, size_t elements, LinearAllocKind kind) REQUIRES(!lock_) {
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return reinterpret_cast<T*>(Alloc(self, elements * sizeof(T), kind));
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}
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// Return the number of bytes used in the allocator.
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size_t GetUsedMemory() const REQUIRES(!lock_);
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ArenaPool* GetArenaPool() REQUIRES(!lock_);
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// Force arena allocator to ask for a new arena on next allocation. This
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// is to preserve private/shared clean pages across zygote fork.
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void SetupForPostZygoteFork(Thread* self) REQUIRES(!lock_);
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// Return true if the linear alloc contains an address.
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bool Contains(void* ptr) const REQUIRES(!lock_);
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// Unsafe version of 'Contains' only to be used when the allocator is going
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// to be deleted.
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bool ContainsUnsafe(void* ptr) const NO_THREAD_SAFETY_ANALYSIS {
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return allocator_.Contains(ptr);
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}
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// Set the given object as the first object for all the pages where the
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// page-beginning overlaps with the object.
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void SetFirstObject(void* begin, size_t bytes) const REQUIRES(lock_);
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private:
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mutable Mutex lock_ DEFAULT_MUTEX_ACQUIRED_AFTER;
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ArenaAllocator allocator_ GUARDED_BY(lock_);
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const bool track_allocations_;
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DISALLOW_IMPLICIT_CONSTRUCTORS(LinearAlloc);
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};
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} // namespace art
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#endif // ART_RUNTIME_LINEAR_ALLOC_H_
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