Python 代码优化 用Digraph可视化基本块和DAG ➢要求能自动对输入的四元式进行基本块的划分，并对基本块内的代码利用DAG进行优化，生成优化后的四元式代码。

以下是一个使用Python和Graphviz库实现的示例代码，可以自动对输入的四元式进行基本块划分，并使用DAG优化算法对基本块内的代码进行优化。最后，它将生成可视化的基本块和DAG图形。 ```python from graphviz import Digraph # 定义四元式列表 quadruples = [ ("+", "a", "b", "t1"), ("*", "t1", "c", "t2"), ("-", "t2", "d", "t3"), ("=", "t3", "", "e"), ("if", "e", "", "L1"), ("+", "f", "g", "t4"), ("*", "t4", "h", "t5"), ("-", "t5", "i", "t6"), ("=", "t6", "", "j"), ("goto", "", "", "L2"), ("label", "", "", "L1"), ("print", "k", "", ""), ("label", "", "", "L2") ] # 划分基本块 basic_blocks = [] current_block = [] for quadruple in quadruples: current_block.append(quadruple) if quadruple[0] == "if" or quadruple[0] == "goto" or quadruple[0] == "label": basic_blocks.append(current_block) current_block = [] # 生成基本块图形 block_graph = Digraph(comment="Basic Blocks") for i, block in enumerate(basic_blocks): with block_graph.subgraph(name=f"cluster_{i}") as subgraph: subgraph.attr(label=f"Block {i}") for quadruple in block: subgraph.node(str(quadruple), str(quadruple)) # 对每个基本块进行DAG优化 optimized_quadruples = [] for block in basic_blocks: dag = {} for quadruple in block: if quadruple[0] == "=": if quadruple[1] not in dag: dag[quadruple[1]] = {"op": "=", "arg1": quadruple[2], "arg2": None} else: dag