d97be81828
By default, we add a lot of build in functions that may never get called. This commit adds a simple reachability graph algorithm to remove functions that can't be called from outside. Also, unmarks a lot of functions as being exported. It was the default to export - now it's the default to not export. Also, some general cleanup to the wasm statement calls.
88 lines
2.2 KiB
Python
88 lines
2.2 KiB
Python
"""
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stdlib: Memory allocation
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"""
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from phasm.wasmgenerator import Generator, func_wrapper
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from phasm.wasmgenerator import VarType_i32 as i32
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IDENTIFIER = 0xA1C0
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ADR_IDENTIFIER = 0
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ADR_RESERVED0 = ADR_IDENTIFIER + 4
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ADR_FREE_BLOCK_PTR = ADR_RESERVED0 + 4
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ADR_UNALLOC_PTR = ADR_FREE_BLOCK_PTR + 4
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UNALLOC_PTR = ADR_UNALLOC_PTR + 4
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# For memory initialization see phasm.compiler.module_data
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@func_wrapper()
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def __find_free_block__(g: Generator, alloc_size: i32) -> i32:
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# Find out if we've freed any blocks at all so far
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g.i32.const(ADR_FREE_BLOCK_PTR)
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g.i32.load()
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g.i32.const(0)
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g.i32.eq()
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with g.if_():
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g.i32.const(0)
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g.return_()
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del alloc_size # TODO: Actual implement using a previously freed block
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g.unreachable()
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return i32('return') # To satisfy mypy
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@func_wrapper(exported=True)
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def __alloc__(g: Generator, alloc_size: i32) -> i32:
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result = i32('result')
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# Check if the memory is already initialized
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g.i32.const(ADR_IDENTIFIER)
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g.i32.load()
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g.i32.const(IDENTIFIER)
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g.i32.ne()
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with g.if_():
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# Not yet initialized, or memory corruption
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g.unreachable()
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# Try to claim a free block
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g.local.get(alloc_size)
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g.call(__find_free_block__)
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g.local.set(result)
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# Check if there was a free block
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g.local.get(result)
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g.i32.const(0)
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g.i32.eq()
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with g.if_():
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# No free blocks, increase allocated memory usage
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# Put the address on the stack in advance so we can store to it later
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g.i32.const(ADR_UNALLOC_PTR)
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# Get the current unalloc pointer value
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g.i32.const(ADR_UNALLOC_PTR)
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g.i32.load()
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g.local.tee(result)
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# Calculate new unalloc pointer value
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g.i32.const(4) # Header size
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g.i32.add()
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g.local.get(alloc_size)
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g.i32.add()
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# Store new unalloc pointer value (address was set on stack in advance)
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g.i32.store()
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# Store block size in the header
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g.local.get(result)
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g.local.get(alloc_size)
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g.i32.store()
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# Return address of the allocated memory, skipping the allocator header
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g.local.get(result)
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g.i32.const(4) # Header size
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g.i32.add()
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return i32('return') # To satisfy mypy
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