Method IsValid

cfa/if_else.go:119–149

IsValid reports whether the cond, body_true, body_false and exit node candidates of prim form a valid 2-way conditional statement in g. Control flow graph: cond ↙ ↘ body_true body_false ↘ ↙ exit

(g graph.Directed, dom cfg.DominatorTree)

//             ↘    ↙
//              exit
func (prim IfElse) IsValid(g graph.Directed, dom cfg.DominatorTree) bool {
	// Dominator sanity check.
	cond, bodyTrue, bodyFalse, exit := prim.Cond, prim.BodyTrue, prim.BodyFalse, prim.Exit
	if !dom.Dominates(cond, bodyTrue) || !dom.Dominates(cond, bodyFalse) || !dom.Dominates(cond, exit) {
		return false
	}

	// Verify that cond has two successors (body_true and body_false).
	condSuccs := g.From(cond)
	if len(condSuccs) != 2 || !g.HasEdgeFromTo(cond, bodyTrue) || !g.HasEdgeFromTo(cond, bodyFalse) {
		return false
	}

	// Verify that body_true has one predecessor (cond) and one successor (exit).
	bodyTrueSuccs := g.From(bodyTrue)
	bodyTruePreds := g.To(bodyTrue)
	if len(bodyTruePreds) != 1 || len(bodyTrueSuccs) != 1 || !g.HasEdgeFromTo(bodyTrue, exit) {
		return false
	}

	// Verify that body_false has one predecessor (cond) and one successor (exit).
	bodyFalseSuccs := g.From(bodyFalse)
	bodyFalsePreds := g.To(bodyFalse)
	if len(bodyFalsePreds) != 1 || len(bodyFalseSuccs) != 1 || !g.HasEdgeFromTo(bodyFalse, exit) {
		return false
	}

	// Verify that exit has two predecessor (body_true and body_false).
	exitPreds := g.To(exit)
	return len(exitPreds) == 2
}