status-go/vendor/honnef.co/go/tools/functions/loops.go

55 lines
989 B
Go

package functions
import "honnef.co/go/tools/ssa"
type Loop struct{ ssa.BlockSet }
func FindLoops(fn *ssa.Function) []Loop {
if fn.Blocks == nil {
return nil
}
tree := fn.DomPreorder()
var sets []Loop
for _, h := range tree {
for _, n := range h.Preds {
if !h.Dominates(n) {
continue
}
// n is a back-edge to h
// h is the loop header
if n == h {
set := Loop{}
set.Add(n)
sets = append(sets, set)
continue
}
set := Loop{}
set.Add(h)
set.Add(n)
for _, b := range allPredsBut(n, h, nil) {
set.Add(b)
}
sets = append(sets, set)
}
}
return sets
}
func allPredsBut(b, but *ssa.BasicBlock, list []*ssa.BasicBlock) []*ssa.BasicBlock {
outer:
for _, pred := range b.Preds {
if pred == but {
continue
}
for _, p := range list {
// TODO improve big-o complexity of this function
if pred == p {
continue outer
}
}
list = append(list, pred)
list = allPredsBut(pred, but, list)
}
return list
}