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// Copyright 2014 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <cstddef>
#include <vector>
#include "Common/Assert.h"
#include "Common/CommonTypes.h"
#include "Common/MemoryUtil.h"
namespace Common
{
// 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, bool executable = true>
class CodeBlock : public T
{
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 of region we can use.
size_t region_size = 0;
// Original size of the region we allocated.
size_t total_region_size = 0;
bool m_is_child = false;
std::vector<CodeBlock*> m_children;
public:
CodeBlock() = default;
virtual ~CodeBlock()
{
if (region)
FreeCodeSpace();
}
CodeBlock(const CodeBlock&) = delete;
CodeBlock& operator=(const CodeBlock&) = delete;
CodeBlock(CodeBlock&&) = delete;
CodeBlock& operator=(CodeBlock&&) = delete;
// Call this before you generate any code.
void AllocCodeSpace(size_t size)
{
region_size = size;
total_region_size = size;
if constexpr (executable)
region = static_cast<u8*>(Common::AllocateExecutableMemory(total_region_size));
else
region = static_cast<u8*>(Common::AllocateMemoryPages(total_region_size));
T::SetCodePtr(region, region + size);
}
// 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()
{
ASSERT(!m_is_child);
Common::FreeMemoryPages(region, total_region_size);
region = nullptr;
region_size = 0;
total_region_size = 0;
for (CodeBlock* child : m_children)
{
child->region = nullptr;
child->region_size = 0;
child->total_region_size = 0;
}
}
bool IsInSpace(const u8* ptr) const { return ptr >= region && ptr < (region + region_size); }
bool IsInSpaceOrChildSpace(const u8* ptr) const
{
return ptr >= region && ptr < (region + total_region_size);
}
void WriteProtect(bool allow_execute)
{
Common::WriteProtectMemory(region, region_size, allow_execute);
}
void UnWriteProtect(bool allow_execute)
{
Common::UnWriteProtectMemory(region, region_size, allow_execute);
}
void ResetCodePtr() { T::SetCodePtr(region, region + region_size); }
size_t GetSpaceLeft() const
{
ASSERT(static_cast<size_t>(T::GetCodePtr() - region) < region_size);
return region_size - (T::GetCodePtr() - region);
}
bool IsAlmostFull() const
{
// This should be bigger than the biggest block ever.
return GetSpaceLeft() < 0x10000;
}
bool HasChildren() const { return region_size != total_region_size; }
u8* AllocChildCodeSpace(size_t child_size)
{
ASSERT_MSG(DYNA_REC, child_size <= GetSpaceLeft(), "Insufficient space for child allocation.");
u8* child_region = region + region_size - child_size;
region_size -= child_size;
ResetCodePtr();
return child_region;
}
void AddChildCodeSpace(CodeBlock* child, size_t child_size)
{
u8* child_region = AllocChildCodeSpace(child_size);
child->m_is_child = true;
child->region = child_region;
child->region_size = child_size;
child->total_region_size = child_size;
child->ResetCodePtr();
m_children.emplace_back(child);
}
};
} // namespace Common
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