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serenity/Libraries/LibJS/Heap/Heap.h
Andreas Kling 69bae3fd9a LibJS: Prevent object shape transitions during runtime object buildup
While initialization common runtime objects like functions, prototypes,
etc, we don't really care about tracking transitions for each and every
property added to them.

This patch puts objects into a "disable transitions" mode while we call
initialize() on them. After that, adding more properties will cause new
transitions to be generated and added to the chain.

This gives a ~10% speed-up on test-js. :^)
2020-10-05 20:53:00 +02:00

121 lines
4.1 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/HashTable.h>
#include <AK/Noncopyable.h>
#include <AK/NonnullOwnPtr.h>
#include <AK/Types.h>
#include <AK/Vector.h>
#include <LibCore/Forward.h>
#include <LibJS/Forward.h>
#include <LibJS/Heap/Handle.h>
#include <LibJS/Runtime/Cell.h>
#include <LibJS/Runtime/Object.h>
namespace JS {
class Heap {
AK_MAKE_NONCOPYABLE(Heap);
AK_MAKE_NONMOVABLE(Heap);
public:
explicit Heap(VM&);
~Heap();
template<typename T, typename... Args>
T* allocate_without_global_object(Args&&... args)
{
auto* memory = allocate_cell(sizeof(T));
new (memory) T(forward<Args>(args)...);
return static_cast<T*>(memory);
}
template<typename T, typename... Args>
T* allocate(GlobalObject& global_object, Args&&... args)
{
auto* memory = allocate_cell(sizeof(T));
new (memory) T(forward<Args>(args)...);
auto* cell = static_cast<T*>(memory);
constexpr bool is_object = IsBaseOf<Object, T>::value;
if constexpr (is_object)
static_cast<Object*>(cell)->disable_transitions();
cell->initialize(global_object);
if constexpr (is_object)
static_cast<Object*>(cell)->enable_transitions();
return cell;
}
enum class CollectionType {
CollectGarbage,
CollectEverything,
};
void collect_garbage(CollectionType = CollectionType::CollectGarbage, bool print_report = false);
VM& vm() { return m_vm; }
bool should_collect_on_every_allocation() const { return m_should_collect_on_every_allocation; }
void set_should_collect_on_every_allocation(bool b) { m_should_collect_on_every_allocation = b; }
void did_create_handle(Badge<HandleImpl>, HandleImpl&);
void did_destroy_handle(Badge<HandleImpl>, HandleImpl&);
void did_create_marked_value_list(Badge<MarkedValueList>, MarkedValueList&);
void did_destroy_marked_value_list(Badge<MarkedValueList>, MarkedValueList&);
void defer_gc(Badge<DeferGC>);
void undefer_gc(Badge<DeferGC>);
private:
Cell* allocate_cell(size_t);
void gather_roots(HashTable<Cell*>&);
void gather_conservative_roots(HashTable<Cell*>&);
void mark_live_cells(const HashTable<Cell*>& live_cells);
void sweep_dead_cells(bool print_report, const Core::ElapsedTimer&);
Cell* cell_from_possible_pointer(FlatPtr);
size_t m_max_allocations_between_gc { 10000 };
size_t m_allocations_since_last_gc { false };
bool m_should_collect_on_every_allocation { false };
VM& m_vm;
Vector<NonnullOwnPtr<HeapBlock>> m_blocks;
HashTable<HandleImpl*> m_handles;
HashTable<MarkedValueList*> m_marked_value_lists;
size_t m_gc_deferrals { 0 };
bool m_should_gc_when_deferral_ends { false };
bool m_collecting_garbage { false };
};
}