Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
++ // Qt-Security score:significant
++
++ #include "qv4executableallocator_p.h"
++ #include <QtQml/private/qv4functiontable_p.h>
++
++ #include <wtf/StdLibExtras.h>
++ #include <wtf/PageAllocation.h>
++
++ using namespace QV4;
++
++ void *ExecutableAllocator::Allocation::exceptionHandlerStart() const
++ {
++ return reinterpret_cast<void*>(addr);
++ }
++
++ size_t ExecutableAllocator::Allocation::exceptionHandlerSize() const
++ {
++ return QV4::exceptionHandlerSize();
++ }
++
++ void *ExecutableAllocator::Allocation::memoryStart() const
++ {
++ return reinterpret_cast<void*>(addr);
++ }
++
++ void *ExecutableAllocator::Allocation::codeStart() const
++ {
++ return reinterpret_cast<void*>(addr + exceptionHandlerSize());
++ }
++
++ 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;
++ }
++
++ 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()
++ = default;
++
++ ExecutableAllocator::~ExecutableAllocator()
++ {
++ for (ChunkOfPages *chunk : std::as_const(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 = nullptr;
++
++ // Code is best aligned to 16-byte boundaries.
++ size = WTF::roundUpToMultipleOf(16, size + exceptionHandlerSize());
++
++ 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);
++ if (!merged)
++ freeAllocations.insert(allocation->size, allocation);
++
++ allocation = nullptr;
++
++ 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 nullptr;
++ return *it;
++ }
++