qv4executableallocator.cpp 6.58 KiB
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#include "qv4executableallocator_p.h"
#include <wtf/StdLibExtras.h>
#include <wtf/PageAllocation.h>
using namespace QV4;
void *ExecutableAllocator::Allocation::start() const
    return reinterpret_cast<void*>(addr);
void ExecutableAllocator::Allocation::deallocate(ExecutableAllocator *allocator)
    if (isValid())
        allocator->free(this);
    else
        delete this;
ExecutableAllocator::Allocation *ExecutableAllocator::Allocation::split(size_t dividingSize)
    Allocation *remainder = new Allocation;
    if (next)
        next->prev = remainder;
    remainder->next = next;
    next = remainder;
    remainder->prev = this;
    remainder->size = size - dividingSize;
    remainder->free = free;
    remainder->addr = addr + dividingSize;
    size = dividingSize;
    return remainder;
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} bool ExecutableAllocator::Allocation::mergeNext(ExecutableAllocator *allocator) { Q_ASSERT(free); if (!next || !next->free) return false; allocator->freeAllocations.remove(size, this); allocator->freeAllocations.remove(next->size, next); size += next->size; Allocation *newNext = next->next; delete next; next = newNext; if (next) next->prev = this; allocator->freeAllocations.insert(size, this); return true; } bool ExecutableAllocator::Allocation::mergePrevious(ExecutableAllocator *allocator) { Q_ASSERT(free); if (!prev || !prev->free) return false; allocator->freeAllocations.remove(size, this); allocator->freeAllocations.remove(prev->size, prev); prev->size += size; if (next) next->prev = prev; prev->next = next; allocator->freeAllocations.insert(prev->size, prev); delete this; return true; } ExecutableAllocator::ChunkOfPages::~ChunkOfPages() { Allocation *alloc = firstAllocation; while (alloc) { Allocation *next = alloc->next; if (alloc->isValid()) delete alloc; alloc = next; } pages->deallocate(); delete pages; } bool ExecutableAllocator::ChunkOfPages::contains(Allocation *alloc) const { Allocation *it = firstAllocation; while (it) { if (it == alloc) return true; it = it->next; } return false; } ExecutableAllocator::ExecutableAllocator() : mutex(QMutex::NonRecursive) { }
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ExecutableAllocator::~ExecutableAllocator() { foreach (ChunkOfPages *chunk, chunks) { for (Allocation *allocation = chunk->firstAllocation; allocation; allocation = allocation->next) if (!allocation->free) allocation->invalidate(); } qDeleteAll(chunks); } ExecutableAllocator::Allocation *ExecutableAllocator::allocate(size_t size) { QMutexLocker locker(&mutex); Allocation *allocation = 0; // Code is best aligned to 16-byte boundaries. size = WTF::roundUpToMultipleOf(16, size); QMultiMap<size_t, Allocation*>::Iterator it = freeAllocations.lowerBound(size); if (it != freeAllocations.end()) { allocation = *it; freeAllocations.erase(it); } if (!allocation) { ChunkOfPages *chunk = new ChunkOfPages; size_t allocSize = WTF::roundUpToMultipleOf(WTF::pageSize(), size); chunk->pages = new WTF::PageAllocation(WTF::PageAllocation::allocate(allocSize, OSAllocator::JSJITCodePages)); chunks.insert(reinterpret_cast<quintptr>(chunk->pages->base()) - 1, chunk); allocation = new Allocation; allocation->addr = reinterpret_cast<quintptr>(chunk->pages->base()); allocation->size = allocSize; allocation->free = true; chunk->firstAllocation = allocation; } Q_ASSERT(allocation); Q_ASSERT(allocation->free); allocation->free = false; if (allocation->size > size) { Allocation *remainder = allocation->split(size); remainder->free = true; if (!remainder->mergeNext(this)) freeAllocations.insert(remainder->size, remainder); } return allocation; } void ExecutableAllocator::free(Allocation *allocation) { QMutexLocker locker(&mutex); Q_ASSERT(allocation); allocation->free = true; QMap<quintptr, ChunkOfPages*>::Iterator it = chunks.lowerBound(allocation->addr); if (it != chunks.begin()) --it; Q_ASSERT(it != chunks.end()); ChunkOfPages *chunk = *it; Q_ASSERT(chunk->contains(allocation)); bool merged = allocation->mergeNext(this); merged |= allocation->mergePrevious(this);
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if (!merged) freeAllocations.insert(allocation->size, allocation); allocation = 0; if (!chunk->firstAllocation->next) { freeAllocations.remove(chunk->firstAllocation->size, chunk->firstAllocation); chunks.erase(it); delete chunk; return; } } ExecutableAllocator::ChunkOfPages *ExecutableAllocator::chunkForAllocation(Allocation *allocation) const { QMutexLocker locker(&mutex); QMap<quintptr, ChunkOfPages*>::ConstIterator it = chunks.lowerBound(allocation->addr); if (it != chunks.begin()) --it; if (it == chunks.end()) return 0; return *it; }