ExecutableAllocator.h [plain text]
#ifndef ExecutableAllocator_h
#define ExecutableAllocator_h
#include "JITCompilationEffort.h"
#include <stddef.h> // for ptrdiff_t
#include <limits>
#include <wtf/Assertions.h>
#include <wtf/MetaAllocatorHandle.h>
#include <wtf/MetaAllocator.h>
#include <wtf/PageAllocation.h>
#include <wtf/RefCounted.h>
#include <wtf/Vector.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 CPU(SH4) && OS(LINUX)
#include <asm/cachectl.h>
#include <asm/unistd.h>
#include <sys/syscall.h>
#include <unistd.h>
#endif
#define JIT_ALLOCATOR_LARGE_ALLOC_SIZE (pageSize() * 4)
#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
#define PROTECTION_FLAGS_RW (PROT_READ | PROT_WRITE)
#define PROTECTION_FLAGS_RX (PROT_READ | PROT_EXEC)
#define EXECUTABLE_POOL_WRITABLE false
#else
#define EXECUTABLE_POOL_WRITABLE true
#endif
namespace JSC {
class VM;
void releaseExecutableMemory(VM&);
static const unsigned jitAllocationGranule = 32;
typedef WTF::MetaAllocatorHandle ExecutableMemoryHandle;
#if ENABLE(ASSEMBLER)
#if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
class DemandExecutableAllocator;
#endif
#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
#if CPU(ARM)
static const size_t fixedExecutableMemoryPoolSize = 16 * 1024 * 1024;
#elif CPU(ARM64)
static const size_t fixedExecutableMemoryPoolSize = 32 * 1024 * 1024;
#elif CPU(X86_64)
static const size_t fixedExecutableMemoryPoolSize = 1024 * 1024 * 1024;
#else
static const size_t fixedExecutableMemoryPoolSize = 32 * 1024 * 1024;
#endif
static const double executablePoolReservationFraction = 0.25;
extern uintptr_t startOfFixedExecutableMemoryPool;
#endif
class ExecutableAllocator {
enum ProtectionSetting { Writable, Executable };
public:
ExecutableAllocator(VM&);
~ExecutableAllocator();
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(VM&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort);
#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
static void makeWritable(void* start, size_t size)
{
reprotectRegion(start, size, Writable);
}
static void makeExecutable(void* start, size_t size)
{
reprotectRegion(start, size, Executable);
}
#else
static void makeWritable(void*, size_t) {}
static void makeExecutable(void*, size_t) {}
#endif
static size_t committedByteCount();
private:
#if ENABLE(ASSEMBLER_WX_EXCLUSIVE)
static void reprotectRegion(void*, size_t, ProtectionSetting);
#if ENABLE(EXECUTABLE_ALLOCATOR_DEMAND)
std::unique_ptr<DemandExecutableAllocator> m_allocator;
DemandExecutableAllocator* allocator() { return m_allocator.get(); }
#endif
#endif
};
#endif // ENABLE(JIT) && ENABLE(ASSEMBLER)
}
#endif // !defined(ExecutableAllocator)