71 lines
2.3 KiB
Python
71 lines
2.3 KiB
Python
"""
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CAP, SSA Intro, Elimination and Optimisations
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Functions to convert a CFG into SSA Form.
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"""
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from typing import List, Dict, Set
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from Lib.CFG import Block, CFG
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from Lib.Operands import Renamer
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from Lib.Statement import Instruction
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from Lib.PhiNode import PhiNode
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from Lib.Dominators import computeDom, computeDT, computeDF
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def insertPhis(cfg: CFG, DF: Dict[Block, Set[Block]]) -> None:
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"""
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`insertPhis(CFG, DF)` inserts phi nodes in `cfg` where needed.
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At this point, phi nodes will look like `temp_x = φ(temp_x, ..., temp_x)`.
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This is an helper function called during SSA entry.
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"""
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for var, defs in cfg.gather_defs().items():
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has_phi: Set[Block] = set()
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queue: List[Block] = list(defs)
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while queue:
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d = queue.pop(0)
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for b in DF[d]:
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if b not in has_phi:
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# TODO add a phi node in block `b` (Lab 5a, Exercise 4)
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raise NotImplementedError("insertPhis")
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def rename_block(cfg: CFG, DT: Dict[Block, Set[Block]], renamer: Renamer, b: Block) -> None:
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"""
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Rename variables from block b.
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This is an auxiliary function for `rename_variables`.
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"""
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renamer = renamer.copy()
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for i in b.get_all_statements():
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if isinstance(i, Instruction | PhiNode):
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i.rename(renamer)
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for succ in cfg.out_blocks(b):
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for i in succ.get_phis():
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assert (isinstance(i, PhiNode))
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i.rename_from(renamer, b.get_label())
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# TODO recursive call(s) of rename_block (Lab 5a, Exercise 5)
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def rename_variables(cfg: CFG, DT: Dict[Block, Set[Block]]) -> None:
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"""
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Rename variables in the CFG, to transform `temp_x = φ(temp_x, ..., temp_x)`
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into `temp_x = φ(temp_0, ... temp_n)`.
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This is an helper function called during SSA entry.
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"""
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renamer = Renamer(cfg.fdata._pool)
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# TODO initial call(s) to rename_block (Lab 5a, Exercise 5)
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def enter_ssa(cfg: CFG, dom_graphs=False, basename="prog") -> None:
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"""
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Convert the CFG `cfg` into SSA Form:
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compute the dominance frontier, then insert phi nodes and finally
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rename variables accordingly.
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`dom_graphs` indicates if we have to print the domination graphs.
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`basename` is used for the names of the produced graphs.
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"""
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# TODO implement this function (Lab 5a, Exercise 2)
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raise NotImplementedError("enter_ssa")
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