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66 lines
2.3 KiB
C++
66 lines
2.3 KiB
C++
// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
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#pragma once
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#include "Luau/CodeGen.h"
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#include <vector>
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#include <stddef.h>
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#include <stdint.h>
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namespace Luau
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{
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namespace CodeGen
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{
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constexpr uint32_t kCodeAlignment = 32;
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struct CodeAllocator
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{
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CodeAllocator(size_t blockSize, size_t maxTotalSize);
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CodeAllocator(size_t blockSize, size_t maxTotalSize, AllocationCallback* allocationCallback, void* allocationCallbackContext);
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~CodeAllocator();
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// Places data and code into the executable page area
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// To allow allocation while previously allocated code is already running, allocation has page granularity
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// It's important to group functions together so that page alignment won't result in a lot of wasted space
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bool allocate(
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const uint8_t* data, size_t dataSize, const uint8_t* code, size_t codeSize, uint8_t*& result, size_t& resultSize, uint8_t*& resultCodeStart);
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// Provided to unwind info callbacks
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void* context = nullptr;
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// Called when new block is created to create and setup the unwinding information for all the code in the block
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// 'startOffset' reserves space for data at the beginning of the page
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void* (*createBlockUnwindInfo)(void* context, uint8_t* block, size_t blockSize, size_t& startOffset) = nullptr;
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// Called to destroy unwinding information returned by 'createBlockUnwindInfo'
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void (*destroyBlockUnwindInfo)(void* context, void* unwindData) = nullptr;
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private:
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// Unwind information can be placed inside the block with some implementation-specific reservations at the beginning
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// But to simplify block space checks, we limit the max size of all that data
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static const size_t kMaxReservedDataSize = 256;
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bool allocateNewBlock(size_t& unwindInfoSize);
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uint8_t* allocatePages(size_t size) const;
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void freePages(uint8_t* mem, size_t size) const;
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// Current block we use for allocations
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uint8_t* blockPos = nullptr;
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uint8_t* blockEnd = nullptr;
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// All allocated blocks
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std::vector<uint8_t*> blocks;
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std::vector<void*> unwindInfos;
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size_t blockSize = 0;
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size_t maxTotalSize = 0;
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AllocationCallback* allocationCallback = nullptr;
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void* allocationCallbackContext = nullptr;
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};
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} // namespace CodeGen
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} // namespace Luau
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