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/*
* Copyright (C) 2008, 2017 Apple Inc. 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 APPLE INC. ``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 APPLE INC. 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 "JITCompilationEffort.h"
#include <stddef.h> // for ptrdiff_t
#include <limits>
#include <wtf/Assertions.h>
#include <wtf/Lock.h>
#include <wtf/MetaAllocatorHandle.h>
#include <wtf/MetaAllocator.h>
#if OS(IOS)
#include <libkern/OSCacheControl.h>
#endif
#if OS(IOS)
#include <sys/mman.h>
#endif
#if CPU(MIPS) && OS(LINUX)
#include <sys/cachectl.h>
#endif
#if ENABLE(FAST_JIT_PERMISSIONS)
#include <os/thread_self_restrict.h>
#endif
#define JIT_ALLOCATOR_LARGE_ALLOC_SIZE (pageSize() * 4)
#define EXECUTABLE_POOL_WRITABLE true
namespace JSC {
static const unsigned jitAllocationGranule = 32;
typedef WTF::MetaAllocatorHandle ExecutableMemoryHandle;
#if ENABLE(ASSEMBLER)
extern JS_EXPORTDATA uintptr_t startOfFixedExecutableMemoryPool;
extern JS_EXPORTDATA uintptr_t endOfFixedExecutableMemoryPool;
inline bool isJITPC(void* pc)
{
return reinterpret_cast<void*>(startOfFixedExecutableMemoryPool) <= pc
&& pc < reinterpret_cast<void*>(endOfFixedExecutableMemoryPool);
}
typedef void (*JITWriteSeparateHeapsFunction)(off_t, const void*, size_t);
extern JS_EXPORTDATA JITWriteSeparateHeapsFunction jitWriteSeparateHeapsFunction;
extern JS_EXPORTDATA bool useFastPermisionsJITCopy;
static inline void* performJITMemcpy(void *dst, const void *src, size_t n)
{
if (reinterpret_cast<uintptr_t>(dst) >= startOfFixedExecutableMemoryPool && reinterpret_cast<uintptr_t>(dst) < endOfFixedExecutableMemoryPool) {
#if ENABLE(FAST_JIT_PERMISSIONS)
if (useFastPermisionsJITCopy) {
os_thread_self_restrict_rwx_to_rw();
memcpy(dst, src, n);
os_thread_self_restrict_rwx_to_rx();
return dst;
}
#endif
if (jitWriteSeparateHeapsFunction) {
// Use execute-only write thunk for writes inside the JIT region. This is a variant of
// memcpy that takes an offset into the JIT region as its destination (first) parameter.
off_t offset = (off_t)((uintptr_t)dst - startOfFixedExecutableMemoryPool);
jitWriteSeparateHeapsFunction(offset, src, n);
return dst;
}
}
// Use regular memcpy for writes outside the JIT region.
return memcpy(dst, src, n);
}
class ExecutableAllocator {
enum ProtectionSetting { Writable, Executable };
public:
static ExecutableAllocator& singleton();
static void initializeAllocator();
bool isValid() const;
static bool underMemoryPressure();
static double memoryPressureMultiplier(size_t addedMemoryUsage);
#if ENABLE(META_ALLOCATOR_PROFILE)
static void dumpProfile();
#else
static void dumpProfile() { }
#endif
RefPtr<ExecutableMemoryHandle> allocate(size_t sizeInBytes, void* ownerUID, JITCompilationEffort);
bool isValidExecutableMemory(const AbstractLocker&, void* address);
static size_t committedByteCount();
Lock& getLock() const;
private:
ExecutableAllocator();
~ExecutableAllocator();
};
#else
inline bool isJITPC(void*) { return false; }
#endif // ENABLE(JIT) && ENABLE(ASSEMBLER)
} // namespace JSC
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