forked from dolphin-emu/dolphin
102 lines
2.9 KiB
C++
102 lines
2.9 KiB
C++
// Copyright 2014 Dolphin Emulator Project
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// Licensed under GPLv2+
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// Refer to the license.txt file included.
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#pragma once
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#include <cstddef>
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#include "Common/Assert.h"
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#include "Common/CommonTypes.h"
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#include "Common/MemoryUtil.h"
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#include "Common/NonCopyable.h"
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// Everything that needs to generate code should inherit from this.
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// You get memory management for free, plus, you can use all emitter functions without
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// having to prefix them with gen-> or something similar.
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// Example implementation:
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// class JIT : public CodeBlock<ARMXEmitter> {}
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template <class T>
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class CodeBlock : public T, NonCopyable
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{
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private:
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// A privately used function to set the executable RAM space to something invalid.
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// For debugging usefulness it should be used to set the RAM to a host specific breakpoint
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// instruction
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virtual void PoisonMemory() = 0;
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protected:
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u8* region = nullptr;
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size_t region_size = 0;
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size_t parent_region_size = 0;
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bool m_has_child = false;
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bool m_is_child = false;
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CodeBlock* m_child = nullptr;
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public:
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virtual ~CodeBlock()
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{
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if (region)
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FreeCodeSpace();
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}
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// Call this before you generate any code.
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void AllocCodeSpace(size_t size, bool need_low = true)
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{
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region_size = size;
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region = static_cast<u8*>(Common::AllocateExecutableMemory(region_size, need_low));
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T::SetCodePtr(region);
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}
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// Always clear code space with breakpoints, so that if someone accidentally executes
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// uninitialized, it just breaks into the debugger.
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void ClearCodeSpace()
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{
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PoisonMemory();
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ResetCodePtr();
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}
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// Call this when shutting down. Don't rely on the destructor, even though it'll do the job.
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void FreeCodeSpace()
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{
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Common::FreeMemoryPages(region, region_size);
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region = nullptr;
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region_size = 0;
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parent_region_size = 0;
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if (m_has_child)
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{
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m_child->region = nullptr;
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m_child->region_size = 0;
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}
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}
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bool IsInSpace(const u8* ptr) const { return ptr >= region && ptr < (region + region_size); }
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// Cannot currently be undone. Will write protect the entire code region.
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// Start over if you need to change the code (call FreeCodeSpace(), AllocCodeSpace()).
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void WriteProtect() { Common::WriteProtectMemory(region, region_size, true); }
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void ResetCodePtr() { T::SetCodePtr(region); }
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size_t GetSpaceLeft() const
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{
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return (m_has_child ? parent_region_size : region_size) - (T::GetCodePtr() - region);
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}
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bool IsAlmostFull() const
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{
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// This should be bigger than the biggest block ever.
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return GetSpaceLeft() < 0x10000;
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}
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void AddChildCodeSpace(CodeBlock* child, size_t size)
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{
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_assert_msg_(DYNA_REC, !m_has_child, "Already have a child! Can't have another!");
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m_child = child;
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m_has_child = true;
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m_child->m_is_child = true;
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u8* child_region = region + region_size - size;
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m_child->region = child_region;
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m_child->region_size = size;
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m_child->ResetCodePtr();
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parent_region_size = region_size - size;
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}
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};
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