citra/src/common/code_block.h

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// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.
#pragma once
#include <cstddef>
#include "common/common_types.h"
#include "common/memory_util.h"
// Everything that needs to generate code should inherit from this.
// You get memory management for free, plus, you can use all emitter functions without
// having to prefix them with gen-> or something similar.
// Example implementation:
// class JIT : public CodeBlock<ARMXEmitter> {}
template<class T> class CodeBlock : public T, NonCopyable
{
private:
// A privately used function to set the executable RAM space to something invalid.
// For debugging usefulness it should be used to set the RAM to a host specific breakpoint instruction
virtual void PoisonMemory() = 0;
protected:
u8 *region;
size_t region_size;
public:
CodeBlock() : region(nullptr), region_size(0) {}
virtual ~CodeBlock() { if (region) FreeCodeSpace(); }
// Call this before you generate any code.
void AllocCodeSpace(int size)
{
region_size = size;
region = (u8*)AllocateExecutableMemory(region_size);
T::SetCodePtr(region);
}
// Always clear code space with breakpoints, so that if someone accidentally executes
// uninitialized, it just breaks into the debugger.
void ClearCodeSpace()
{
PoisonMemory();
ResetCodePtr();
}
// Call this when shutting down. Don't rely on the destructor, even though it'll do the job.
void FreeCodeSpace()
{
#ifdef __SYMBIAN32__
ResetExecutableMemory(region);
#else
FreeMemoryPages(region, region_size);
#endif
region = nullptr;
region_size = 0;
}
bool IsInSpace(const u8 *ptr)
{
return (ptr >= region) && (ptr < (region + region_size));
}
// Cannot currently be undone. Will write protect the entire code region.
// Start over if you need to change the code (call FreeCodeSpace(), AllocCodeSpace()).
void WriteProtect()
{
WriteProtectMemory(region, region_size, true);
}
void ResetCodePtr()
{
T::SetCodePtr(region);
}
size_t GetSpaceLeft() const
{
return region_size - (T::GetCodePtr() - region);
}
u8 *GetBasePtr() {
return region;
}
size_t GetOffset(const u8 *ptr) const {
return ptr - region;
}
};