// 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)
}
}
func visitPhi(inst *ssa.Phi, fr *frame) {
// In the case of channels, find the last defined channel and replace it.
if _, ok := inst.Type().(*types.Chan); ok {
//preds := inst.Block().Preds // PredBlocks: order is significant.
fr.locals[inst], _ = fr.get(inst.Edges[0])
fr.phi[inst] = inst.Edges
}
}
func (f *Function) Phi(phi *ssa.Phi) (string, *Error) {
if ident := f.Ident(phi); ident == nil {
return ErrorMsg("Error in ssa.Phi allocation")
}
asm := fmt.Sprintf("// BEGIN ssa.Phi, name (%v), comment (%v), value (%v)\n", phi.Name(), phi.Comment, phi)
asm += fmt.Sprintf("// END ssa.Phi, %v\n", phi)
return asm, nil
}
func visitPhi(instr *ssa.Phi, infer *TypeInfer, ctx *Context) {
loopDetectBounds(instr, infer, ctx)
if _, ok := instr.Type().(*types.Chan); ok {
// Replace existing non-edge extra args with the same name.
for _, e := range instr.Edges {
EALOOP:
for i, ea := range ctx.F.extraargs {
if e.Name() == ea.Name() {
ctx.F.extraargs = append(ctx.F.extraargs[:i], ctx.F.extraargs[i+1:]...)
break EALOOP
}
}
}
ctx.F.extraargs = append(ctx.F.extraargs, instr)
}
}
func (f *Function) computePhiInstr(phi *ssa.Phi) *Error {
blockIndex := phi.Block().Index
for i, edge := range phi.Edges {
edgeBlock := -1
if phi.Block() != nil && i < len(phi.Block().Preds) {
edgeBlock = phi.Block().Preds[i].Index
}
if edgeBlock == -1 {
ice("malformed CFG")
}
if _, ok := f.phiInfo[edgeBlock]; !ok {
f.phiInfo[edgeBlock] = make(map[int][]phiInfo)
}
f.phiInfo[edgeBlock][blockIndex] = append(f.phiInfo[edgeBlock][blockIndex], phiInfo{value: edge, phi: phi})
}
return nil
}
// 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
}