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[dev.regabi] cmd/compile: use OSELRECV2 for all <-c variants
OSELRECV2 can represent all possible receive clauses that can appear in a select statement, and it simplifies later code, so use it instead. Follow up CL will remove OSELRECV. Passes buildall w/ toolstash -cmp. Change-Id: Ibbdae45287ffd888acd8dc89ca8d99e454277cd1 Reviewed-on: https://go-review.googlesource.com/c/go/+/275458 Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com> Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
This commit is contained in:
Cuong Manh Le
parent
88e1415d08
commit
0328c3b660
@ -399,9 +399,6 @@ func (e *Escape) stmt(n ir.Node) {
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e.stmt(cas.Left())
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e.block(cas.Body())
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}
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case ir.OSELRECV:
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n := n.(*ir.AssignStmt)
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e.assign(n.Left(), n.Right(), "selrecv", n)
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case ir.OSELRECV2:
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n := n.(*ir.AssignListStmt)
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e.assign(n.List().First(), n.Rlist().First(), "selrecv", n)
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@ -872,15 +872,14 @@ func (o *Order) stmt(n ir.Node) {
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// give this away).
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case ir.OSELECT:
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t := o.markTemp()
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for _, cas := range n.List().Slice() {
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cas := cas.(*ir.CaseStmt)
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r := cas.Left()
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setlineno(cas)
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for _, ncas := range n.List().Slice() {
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ncas := ncas.(*ir.CaseStmt)
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r := ncas.Left()
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setlineno(ncas)
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// Append any new body prologue to ninit.
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// The next loop will insert ninit into nbody.
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if cas.Init().Len() != 0 {
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if ncas.Init().Len() != 0 {
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base.Fatalf("order select ninit")
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}
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if r == nil {
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@ -891,84 +890,48 @@ func (o *Order) stmt(n ir.Node) {
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ir.Dump("select case", r)
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base.Fatalf("unknown op in select %v", r.Op())
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case ir.OSELRECV, ir.OSELRECV2:
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var dst, ok ir.Node
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var recv *ir.UnaryExpr
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var def bool
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if r.Op() == ir.OSELRECV {
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// case x = <-c
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// case <-c (dst is ir.BlankNode)
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def, dst, ok, recv = r.Colas(), r.Left(), ir.BlankNode, r.Right().(*ir.UnaryExpr)
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} else {
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r := r.(*ir.AssignListStmt)
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// case x, ok = <-c
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def, dst, ok, recv = r.Colas(), r.List().First(), r.List().Second(), r.Rlist().First().(*ir.UnaryExpr)
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}
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// If this is case x := <-ch or case x, y := <-ch, the case has
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// the ODCL nodes to declare x and y. We want to delay that
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// declaration (and possible allocation) until inside the case body.
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// Delete the ODCL nodes here and recreate them inside the body below.
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if def {
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init := r.Init().Slice()
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if len(init) > 0 && init[0].Op() == ir.ODCL && init[0].(*ir.Decl).Left() == dst {
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init = init[1:]
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}
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if len(init) > 0 && init[0].Op() == ir.ODCL && init[0].(*ir.Decl).Left() == ok {
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init = init[1:]
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}
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r.PtrInit().Set(init)
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}
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if r.Init().Len() != 0 {
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ir.DumpList("ninit", r.Init())
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base.Fatalf("ninit on select recv")
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}
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case ir.OSELRECV2:
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// case x, ok = <-c
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recv := r.Rlist().First().(*ir.UnaryExpr)
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recv.SetLeft(o.expr(recv.Left(), nil))
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if recv.Left().Op() != ir.ONAME {
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recv.SetLeft(o.copyExpr(recv.Left()))
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}
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r := r.(*ir.AssignListStmt)
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init := r.PtrInit().Slice()
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r.PtrInit().Set(nil)
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// Introduce temporary for receive and move actual copy into case body.
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// avoids problems with target being addressed, as usual.
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// NOTE: If we wanted to be clever, we could arrange for just one
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// temporary per distinct type, sharing the temp among all receives
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// with that temp. Similarly one ok bool could be shared among all
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// the x,ok receives. Not worth doing until there's a clear need.
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if !ir.IsBlank(dst) {
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// use channel element type for temporary to avoid conversions,
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// such as in case interfacevalue = <-intchan.
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// the conversion happens in the OAS instead.
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if def {
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dcl := ir.Nod(ir.ODCL, dst, nil)
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cas.PtrInit().Append(typecheck(dcl, ctxStmt))
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colas := r.Colas()
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do := func(i int, t *types.Type) {
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n := r.List().Index(i)
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if ir.IsBlank(n) {
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return
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}
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tmp := o.newTemp(recv.Left().Type().Elem(), recv.Left().Type().Elem().HasPointers())
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as := ir.Nod(ir.OAS, dst, tmp)
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cas.PtrInit().Append(typecheck(as, ctxStmt))
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dst = tmp
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}
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if !ir.IsBlank(ok) {
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if def {
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dcl := ir.Nod(ir.ODCL, ok, nil)
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cas.PtrInit().Append(typecheck(dcl, ctxStmt))
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// If this is case x := <-ch or case x, y := <-ch, the case has
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// the ODCL nodes to declare x and y. We want to delay that
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// declaration (and possible allocation) until inside the case body.
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// Delete the ODCL nodes here and recreate them inside the body below.
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if colas {
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if len(init) > 0 && init[0].Op() == ir.ODCL && init[0].(*ir.Decl).Left() == n {
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init = init[1:]
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}
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dcl := ir.Nod(ir.ODCL, n, nil)
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dcl = typecheck(dcl, ctxStmt)
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ncas.PtrInit().Append(dcl)
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}
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tmp := o.newTemp(types.Types[types.TBOOL], false)
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as := ir.Nod(ir.OAS, ok, conv(tmp, ok.Type()))
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cas.PtrInit().Append(typecheck(as, ctxStmt))
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ok = tmp
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tmp := o.newTemp(t, t.HasPointers())
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as := ir.Nod(ir.OAS, n, conv(tmp, n.Type()))
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as = typecheck(as, ctxStmt)
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ncas.PtrInit().Append(as)
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r.PtrList().SetIndex(i, tmp)
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}
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if r.Op() == ir.OSELRECV {
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r.SetLeft(dst)
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} else {
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r := r.(*ir.AssignListStmt)
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r.List().SetIndex(0, dst)
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r.List().SetIndex(1, ok)
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do(0, recv.Left().Type().Elem())
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do(1, types.Types[types.TBOOL])
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if len(init) != 0 {
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ir.DumpList("ninit", r.Init())
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base.Fatalf("ninit on select recv")
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}
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orderBlock(cas.PtrInit(), o.free)
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orderBlock(ncas.PtrInit(), o.free)
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case ir.OSEND:
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if r.Init().Len() != 0 {
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@ -32,6 +32,14 @@ func typecheckselect(sel *ir.SelectStmt) {
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n := ncase.List().First()
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ncase.SetLeft(n)
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ncase.PtrList().Set(nil)
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oselrecv2 := func(dst, recv ir.Node, colas bool) {
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n := ir.NodAt(n.Pos(), ir.OSELRECV2, nil, nil)
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n.PtrList().Set2(dst, ir.BlankNode)
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n.PtrRlist().Set1(recv)
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n.SetColas(colas)
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n.SetTypecheck(1)
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ncase.SetLeft(n)
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}
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switch n.Op() {
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default:
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pos := n.Pos()
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@ -45,7 +53,7 @@ func typecheckselect(sel *ir.SelectStmt) {
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base.ErrorfAt(pos, "select case must be receive, send or assign recv")
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case ir.OAS:
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// convert x = <-c into OSELRECV(x, <-c).
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// convert x = <-c into x, _ = <-c
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// remove implicit conversions; the eventual assignment
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// will reintroduce them.
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if r := n.Right(); r.Op() == ir.OCONVNOP || r.Op() == ir.OCONVIFACE {
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@ -57,10 +65,9 @@ func typecheckselect(sel *ir.SelectStmt) {
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base.ErrorfAt(n.Pos(), "select assignment must have receive on right hand side")
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break
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}
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n.SetOp(ir.OSELRECV)
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oselrecv2(n.Left(), n.Right(), n.Colas())
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case ir.OAS2RECV:
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// convert x, ok = <-c into OSELRECV2(x, <-c) with ntest=ok
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if n.Rlist().First().Op() != ir.ORECV {
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base.ErrorfAt(n.Pos(), "select assignment must have receive on right hand side")
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break
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@ -68,12 +75,8 @@ func typecheckselect(sel *ir.SelectStmt) {
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n.SetOp(ir.OSELRECV2)
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case ir.ORECV:
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// convert <-c into OSELRECV(_, <-c)
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as := ir.NewAssignStmt(n.Pos(), ir.BlankNode, n)
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as.SetOp(ir.OSELRECV)
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as.SetTypecheck(1)
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n = as
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ncase.SetLeft(n)
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// convert <-c into _, _ = <-c
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oselrecv2(ir.BlankNode, n, false)
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case ir.OSEND:
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break
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@ -129,14 +132,6 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
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case ir.OSEND:
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// already ok
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case ir.OSELRECV:
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r := n.(*ir.AssignStmt)
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if ir.IsBlank(r.Left()) {
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n = r.Right()
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break
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}
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r.SetOp(ir.OAS)
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case ir.OSELRECV2:
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r := n.(*ir.AssignListStmt)
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if ir.IsBlank(r.List().First()) && ir.IsBlank(r.List().Second()) {
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@ -165,29 +160,11 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
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dflt = cas
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continue
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}
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// Lower x, _ = <-c to x = <-c.
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if sel := n; sel.Op() == ir.OSELRECV2 {
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if ir.IsBlank(sel.List().Second()) {
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as := ir.NewAssignStmt(sel.Pos(), sel.List().First(), sel.Rlist().First())
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as.SetOp(ir.OSELRECV)
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as.SetTypecheck(1)
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n = as
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cas.SetLeft(n)
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}
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}
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switch n.Op() {
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case ir.OSEND:
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n.SetRight(nodAddr(n.Right()))
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n.SetRight(typecheck(n.Right(), ctxExpr))
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case ir.OSELRECV:
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if !ir.IsBlank(n.Left()) {
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n.SetLeft(nodAddr(n.Left()))
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n.SetLeft(typecheck(n.Left(), ctxExpr))
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}
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case ir.OSELRECV2:
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if !ir.IsBlank(n.List().First()) {
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n.List().SetIndex(0, nodAddr(n.List().First()))
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@ -217,26 +194,23 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
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ch := n.Left()
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call = mkcall1(chanfn("selectnbsend", 2, ch.Type()), types.Types[types.TBOOL], r.PtrInit(), ch, n.Right())
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case ir.OSELRECV:
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// if selectnbrecv(&v, c) { body } else { default body }
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recv := n.Right().(*ir.UnaryExpr)
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ch := recv.Left()
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elem := n.Left()
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if ir.IsBlank(elem) {
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elem = nodnil()
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}
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call = mkcall1(chanfn("selectnbrecv", 2, ch.Type()), types.Types[types.TBOOL], r.PtrInit(), elem, ch)
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case ir.OSELRECV2:
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// if selectnbrecv2(&v, &received, c) { body } else { default body }
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recv := n.Rlist().First().(*ir.UnaryExpr)
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ch := recv.Left()
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elem := n.List().First()
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if ir.IsBlank(elem) {
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elem = nodnil()
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}
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receivedp := typecheck(nodAddr(n.List().Second()), ctxExpr)
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call = mkcall1(chanfn("selectnbrecv2", 2, ch.Type()), types.Types[types.TBOOL], r.PtrInit(), elem, receivedp, ch)
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if ir.IsBlank(n.List().Second()) {
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// if selectnbrecv(&v, c) { body } else { default body }
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call = mkcall1(chanfn("selectnbrecv", 2, ch.Type()), types.Types[types.TBOOL], r.PtrInit(), elem, ch)
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} else {
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// TODO(cuonglm): make this use selectnbrecv()
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// if selectnbrecv2(&v, &received, c) { body } else { default body }
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receivedp := ir.Nod(ir.OADDR, n.List().Second(), nil)
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receivedp = typecheck(receivedp, ctxExpr)
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call = mkcall1(chanfn("selectnbrecv2", 2, ch.Type()), types.Types[types.TBOOL], r.PtrInit(), elem, receivedp, ch)
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}
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}
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r.SetLeft(typecheck(call, ctxExpr))
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@ -292,12 +266,6 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
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nsends++
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c = n.Left()
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elem = n.Right()
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case ir.OSELRECV:
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nrecvs++
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i = ncas - nrecvs
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recv := n.Right().(*ir.UnaryExpr)
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c = recv.Left()
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elem = n.Left()
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case ir.OSELRECV2:
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nrecvs++
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i = ncas - nrecvs
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@ -355,7 +323,7 @@ func walkselectcases(cases ir.Nodes) []ir.Node {
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r := ir.Nod(ir.OIF, cond, nil)
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if n := cas.Left(); n != nil && n.Op() == ir.OSELRECV2 {
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if n := cas.Left(); n != nil && n.Op() == ir.OSELRECV2 && !ir.IsBlank(n.List().Second()) {
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x := ir.Nod(ir.OAS, n.List().Second(), recvOK)
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r.PtrBody().Append(typecheck(x, ctxStmt))
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}
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