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// 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
#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;
}
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