dolphin/Source/Core/Common/CodeBlock.h
2017-01-08 18:40:09 -05:00

102 lines
2.9 KiB
C++

// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
#pragma once
#include <cstddef>
#include "Common/Assert.h"
#include "Common/CommonTypes.h"
#include "Common/MemoryUtil.h"
#include "Common/NonCopyable.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 = nullptr;
size_t region_size = 0;
size_t parent_region_size = 0;
bool m_has_child = false;
bool m_is_child = false;
CodeBlock* m_child = nullptr;
public:
virtual ~CodeBlock()
{
if (region)
FreeCodeSpace();
}
// Call this before you generate any code.
void AllocCodeSpace(size_t size, bool need_low = true)
{
region_size = size;
region = static_cast<u8*>(Common::AllocateExecutableMemory(region_size, need_low));
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()
{
Common::FreeMemoryPages(region, region_size);
region = nullptr;
region_size = 0;
parent_region_size = 0;
if (m_has_child)
{
m_child->region = nullptr;
m_child->region_size = 0;
}
}
bool IsInSpace(const u8* ptr) const { 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() { Common::WriteProtectMemory(region, region_size, true); }
void ResetCodePtr() { T::SetCodePtr(region); }
size_t GetSpaceLeft() const
{
return (m_has_child ? parent_region_size : region_size) - (T::GetCodePtr() - region);
}
bool IsAlmostFull() const
{
// This should be bigger than the biggest block ever.
return GetSpaceLeft() < 0x10000;
}
void AddChildCodeSpace(CodeBlock* child, size_t size)
{
_assert_msg_(DYNA_REC, !m_has_child, "Already have a child! Can't have another!");
m_child = child;
m_has_child = true;
m_child->m_is_child = true;
u8* child_region = region + region_size - size;
m_child->region = child_region;
m_child->region_size = size;
m_child->ResetCodePtr();
parent_region_size = region_size - size;
}
};