def analyze_undefined_regs(
blocks: List[BasicBlock], cfg: CFG, env: Environment,
initial_defined: Set[Value]) -> AnalysisResult[Value]:
"""Calculate potentially undefined registers at each CFG location.
A register is undefined if there is some path from initial block
where it has an undefined value.
"""
initial_undefined = set(env.regs()) - initial_defined
return run_analysis(blocks=blocks,
cfg=cfg,
gen_and_kill=UndefinedVisitor(),
initial=initial_undefined,
backward=False,
kind=MAYBE_ANALYSIS)
def env_to_lines(env: Environment,
names: Dict[Value, str],
const_regs: Optional[Dict[LoadInt, int]] = None) -> List[str]:
result = []
i = 0
regs = list(env.regs())
if const_regs is None:
const_regs = {}
regs = [reg for reg in regs if reg not in const_regs]
while i < len(regs):
i0 = i
group = [names[regs[i0]]]
while i + 1 < len(regs) and regs[i + 1].type == regs[i0].type:
i += 1
group.append(names[regs[i]])
i += 1
result.append('%s :: %s' % (', '.join(group), regs[i0].type))
return result
