analysis.py 文件源码

def analyze_must_defined_regs(
        blocks: List[BasicBlock],
        cfg: CFG,
        initial_defined: Set[Register],
        num_regs: int) -> AnalysisResult[Register]:
    """Calculate always defined registers at each CFG location.

    A register is defined if it has a value along all paths from the initial location.
    """
    return run_analysis(blocks=blocks,
                        cfg=cfg,
                        gen_and_kill=MustDefinedVisitor(),
                        initial=initial_defined,
                        backward=False,
                        kind=MUST_ANALYSIS,
                        universe=set([Register(r) for r in range(num_regs)]))