diff options
Diffstat (limited to 'src/cmd/internal/gc/select.go')
| -rw-r--r-- | src/cmd/internal/gc/select.go | 75 |
1 files changed, 31 insertions, 44 deletions
diff --git a/src/cmd/internal/gc/select.go b/src/cmd/internal/gc/select.go index ab7a1445be..ca6a21def9 100644 --- a/src/cmd/internal/gc/select.go +++ b/src/cmd/internal/gc/select.go @@ -10,16 +10,12 @@ package gc func typecheckselect(sel *Node) { var ncase *Node var n *Node - var def *Node - var l *NodeList - var lno int - var count int - - def = nil - lno = int(setlineno(sel)) - count = 0 + + def := (*Node)(nil) + lno := int(setlineno(sel)) + count := 0 typechecklist(sel.Ninit, Etop) - for l = sel.List; l != nil; l = l.Next { + for l := sel.List; l != nil; l = l.Next { count++ ncase = l.N setlineno(ncase) @@ -94,27 +90,20 @@ func typecheckselect(sel *Node) { } func walkselect(sel *Node) { - var lno int - var i int - var n *Node - var r *Node - var a *Node - var var_ *Node - var selv *Node - var cas *Node - var dflt *Node - var ch *Node - var l *NodeList - var init *NodeList - if sel.List == nil && sel.Xoffset != 0 { Fatal("double walkselect") // already rewrote } - lno = int(setlineno(sel)) - i = count(sel.List) + lno := int(setlineno(sel)) + i := count(sel.List) // optimization: zero-case select + var init *NodeList + var r *Node + var n *Node + var var_ *Node + var selv *Node + var cas *Node if i == 0 { sel.Nbody = list1(mkcall("block", nil, nil)) goto out @@ -124,13 +113,14 @@ func walkselect(sel *Node) { // TODO(rsc): Reenable optimization once order.c can handle it. // golang.org/issue/7672. if i == 1 { - cas = sel.List.N + cas := sel.List.N setlineno(cas) - l = cas.Ninit + l := cas.Ninit if cas.Left != nil { // not default: - n = cas.Left + n := cas.Left l = concat(l, n.Ninit) n.Ninit = nil + var ch *Node switch n.Op { default: Fatal("select %v", Oconv(int(n.Op), 0)) @@ -167,7 +157,7 @@ func walkselect(sel *Node) { } // if ch == nil { block() }; n; - a = Nod(OIF, nil, nil) + a := Nod(OIF, nil, nil) a.Ntest = Nod(OEQ, ch, nodnil()) a.Nbody = list1(mkcall("block", nil, &l)) @@ -183,7 +173,7 @@ func walkselect(sel *Node) { // convert case value arguments to addresses. // this rewrite is used by both the general code and the next optimization. - for l = sel.List; l != nil; l = l.Next { + for l := sel.List; l != nil; l = l.Next { cas = l.N setlineno(cas) n = cas.Left @@ -216,6 +206,8 @@ func walkselect(sel *Node) { // optimization: two-case select but one is default: single non-blocking op. if i == 2 && (sel.List.N.Left == nil || sel.List.Next.N.Left == nil) { + var cas *Node + var dflt *Node if sel.List.N.Left == nil { cas = sel.List.Next.N dflt = sel.List.N @@ -224,9 +216,9 @@ func walkselect(sel *Node) { cas = sel.List.N } - n = cas.Left + n := cas.Left setlineno(n) - r = Nod(OIF, nil, nil) + r := Nod(OIF, nil, nil) r.Ninit = cas.Ninit switch n.Op { default: @@ -234,7 +226,7 @@ func walkselect(sel *Node) { // if selectnbsend(c, v) { body } else { default body } case OSEND: - ch = n.Left + ch := n.Left r.Ntest = mkcall1(chanfn("selectnbsend", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), ch, n.Right) @@ -243,7 +235,7 @@ func walkselect(sel *Node) { r = Nod(OIF, nil, nil) r.Ninit = cas.Ninit - ch = n.Right.Left + ch := n.Right.Left r.Ntest = mkcall1(chanfn("selectnbrecv", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, ch) // if c != nil && selectnbrecv2(&v, c) { body } else { default body } @@ -251,7 +243,7 @@ func walkselect(sel *Node) { r = Nod(OIF, nil, nil) r.Ninit = cas.Ninit - ch = n.Right.Left + ch := n.Right.Left r.Ntest = mkcall1(chanfn("selectnbrecv2", 2, ch.Type), Types[TBOOL], &r.Ninit, typename(ch.Type), n.Left, n.Ntest, ch) } @@ -278,7 +270,7 @@ func walkselect(sel *Node) { init = list(init, r) // register cases - for l = sel.List; l != nil; l = l.Next { + for l := sel.List; l != nil; l = l.Next { cas = l.N setlineno(cas) n = cas.Left @@ -334,14 +326,9 @@ out: // Keep in sync with src/runtime/chan.h. func selecttype(size int32) *Type { - var sel *Node - var sudog *Node - var scase *Node - var arr *Node - // TODO(dvyukov): it's possible to generate SudoG and Scase only once // and then cache; and also cache Select per size. - sudog = Nod(OTSTRUCT, nil, nil) + sudog := Nod(OTSTRUCT, nil, nil) sudog.List = list(sudog.List, Nod(ODCLFIELD, newname(Lookup("g")), typenod(Ptrto(Types[TUINT8])))) sudog.List = list(sudog.List, Nod(ODCLFIELD, newname(Lookup("selectdone")), typenod(Ptrto(Types[TUINT8])))) @@ -355,7 +342,7 @@ func selecttype(size int32) *Type { sudog.Type.Noalg = 1 sudog.Type.Local = 1 - scase = Nod(OTSTRUCT, nil, nil) + scase := Nod(OTSTRUCT, nil, nil) scase.List = list(scase.List, Nod(ODCLFIELD, newname(Lookup("elem")), typenod(Ptrto(Types[TUINT8])))) scase.List = list(scase.List, Nod(ODCLFIELD, newname(Lookup("chan")), typenod(Ptrto(Types[TUINT8])))) scase.List = list(scase.List, Nod(ODCLFIELD, newname(Lookup("pc")), typenod(Types[TUINTPTR]))) @@ -367,12 +354,12 @@ func selecttype(size int32) *Type { scase.Type.Noalg = 1 scase.Type.Local = 1 - sel = Nod(OTSTRUCT, nil, nil) + sel := Nod(OTSTRUCT, nil, nil) sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("tcase")), typenod(Types[TUINT16]))) sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("ncase")), typenod(Types[TUINT16]))) sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("pollorder")), typenod(Ptrto(Types[TUINT8])))) sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("lockorder")), typenod(Ptrto(Types[TUINT8])))) - arr = Nod(OTARRAY, Nodintconst(int64(size)), scase) + arr := Nod(OTARRAY, Nodintconst(int64(size)), scase) sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("scase")), arr)) arr = Nod(OTARRAY, Nodintconst(int64(size)), typenod(Ptrto(Types[TUINT8]))) sel.List = list(sel.List, Nod(ODCLFIELD, newname(Lookup("lockorderarr")), arr)) |