Source/JavaScriptCore/heap/PreciseSubspace.cpp

/*
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 * Redistribution and use in source and binary forms, with or without
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#include "config.h"
#include "PreciseSubspace.h"

#include "AllocatingScope.h"
#include "IsoCellSetInlines.h"
#include "JSCellInlines.h"
#include "MarkedSpaceInlines.h"
#include <wtf/TZoneMallocInlines.h>

namespace JSC {

WTF_MAKE_TZONE_ALLOCATED_IMPL(PreciseSubspace);

PreciseSubspace::PreciseSubspace(CString name, JSC::Heap& heap, const HeapCellType& heapCellType, AlignedMemoryAllocator* allocator)
    : Subspace(SubspaceKind::PreciseSubspace, name, heap)
{
    initialize(heapCellType, allocator);
}

PreciseSubspace::~PreciseSubspace() = default;

void PreciseSubspace::didResizeBits(unsigned)
{
    UNREACHABLE_FOR_PLATFORM();
}

void PreciseSubspace::didRemoveBlock(unsigned)
{
    UNREACHABLE_FOR_PLATFORM();
}

void PreciseSubspace::didBeginSweepingToFreeList(MarkedBlock::Handle*)
{
    UNREACHABLE_FOR_PLATFORM();
}

void* PreciseSubspace::tryAllocate(size_t size)
{
    PreciseAllocation* allocation = PreciseAllocation::tryCreate(m_space.heap(), size, this, 0);
    if (!allocation)
        return nullptr;

    m_preciseAllocations.append(allocation);
    m_space.registerPreciseAllocation(allocation, /* isNewAllocation */ true);
    return allocation->cell();
}

void* PreciseSubspace::allocate(VM& vm, size_t cellSize, GCDeferralContext* deferralContext, AllocationFailureMode failureMode)
{
    ASSERT(vm.currentThreadIsHoldingAPILock());
    ASSERT(!vm.heap.objectSpace().isIterating());
    UNUSED_PARAM(failureMode);
    ASSERT_WITH_MESSAGE(failureMode == AllocationFailureMode::ReturnNull, "PreciseSubspace is meant for large objects so it should always be able to fail.");

    AllocatingScope helpingHeap(vm.heap);

    vm.heap.collectIfNecessaryOrDefer(deferralContext);

    return tryAllocate(cellSize);
}

} // namespace JSC