// loopDetectBounds detects static bounds (or set as dynamic bounds) from based
// on loop state machine.
func loopDetectBounds(instr *ssa.Phi, infer *TypeInfer, ctx *Context) {
switch ctx.L.State {
case Enter:
switch ctx.L.Bound {
case Unknown:
phiSelectEdge(instr, infer, ctx)
loopSetIndex(instr, infer, ctx)
case Static:
switch ctx.L.Bound {
case Static:
phiSelectEdge(instr, infer, ctx)
if instr == ctx.L.IndexVar {
ctx.L.Next()
infer.Logger.Printf(ctx.F.Sprintf(LoopSymbol+"Increment %s by %s to %s", ctx.L.IndexVar.Name(), fmtLoopHL(ctx.L.Step), fmtLoopHL(ctx.L.Index)))
}
default:
visitSkip(instr, infer, ctx)
}
case Dynamic:
phiSelectEdge(instr, infer, ctx)
infer.Logger.Printf(ctx.F.Sprintf(PhiSymbol+"(dynamic bound) %s", instr.String()))
}
default:
phiSelectEdge(instr, infer, ctx)
}
}
// phiSelectEdge selects edge based on predecessor block and returns the edge index.
func phiSelectEdge(instr *ssa.Phi, infer *TypeInfer, ctx *Context) (edge int) {
for i, pred := range instr.Block().Preds {
if pred.Index == ctx.B.Pred {
e, ok := ctx.F.locals[instr.Edges[i]]
if !ok {
switch t := instr.Edges[i].(type) {
case *ssa.Const:
ctx.F.locals[instr.Edges[i]] = &Const{t}
e, edge = ctx.F.locals[instr.Edges[i]], pred.Index
infer.Logger.Printf(ctx.F.Sprintf(PhiSymbol+"%s/%s = %s, selected const from block %d", instr.Name(), e, instr.String(), edge))
case *ssa.Function:
ctx.F.locals[instr.Edges[i]] = &Value{instr.Edges[i], ctx.F.InstanceID(), ctx.L.Index}
e, edge = ctx.F.locals[instr.Edges[i]], pred.Index
infer.Logger.Printf(ctx.F.Sprintf(PhiSymbol+"%s/%s = %s, selected function from block %d", instr.Name(), e, instr.String(), edge))
case *ssa.Call:
ctx.F.locals[instr.Edges[i]] = &Value{instr.Edges[i], ctx.F.InstanceID(), ctx.L.Index}
e, edge = ctx.F.locals[instr.Edges[i]], pred.Index
infer.Logger.Printf(ctx.F.Sprintf(PhiSymbol+"%s/%s = %s, selected call from block %d", instr.Name(), e, instr.String(), edge))
case *ssa.UnOp:
ctx.F.locals[instr.Edges[i]] = &Value{instr.Edges[i], ctx.F.InstanceID(), ctx.L.Index}
e, edge = ctx.F.locals[instr.Edges[i]], pred.Index
infer.Logger.Printf(ctx.F.Sprintf(PhiSymbol+"%s/%s = %s, selected UnOp from block %d", instr.Name(), e, instr.String(), edge))
default:
infer.Logger.Fatalf("phi: create instance Edge[%d]=%#v: %s", i, instr.Edges[i], ErrUnknownValue)
return
}
}
ctx.F.locals[instr], edge = e, pred.Index
infer.Logger.Printf(ctx.F.Sprintf(PhiSymbol+"%s/%s = %s, selected from block %d", instr.Name(), e, instr.String(), edge))
ctx.F.revlookup[instr.Name()] = instr.Edges[i].Name()
if a, ok := ctx.F.arrays[e]; ok {
ctx.F.arrays[ctx.F.locals[instr]] = a
}
if s, ok := ctx.F.structs[e]; ok {
ctx.F.structs[ctx.F.locals[instr]] = s
}
return
}
}
infer.Logger.Fatalf("phi: %d->%d: %s", ctx.B.Pred, instr.Block().Index, ErrPhiUnknownEdge)
return
}