diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go index 7a52ff3b88..31d157b165 100644 --- a/src/cmd/compile/internal/escape/escape.go +++ b/src/cmd/compile/internal/escape/escape.go @@ -347,21 +347,19 @@ func (e *escape) stmt(n ir.Node) { e.loopDepth-- case ir.ORANGE: - // for List = range Right { Nbody } + // for Key, Value = range X { Body } n := n.(*ir.RangeStmt) e.loopDepth++ - ks := e.addrs(n.Vars) + e.addr(n.Key) + k := e.addr(n.Value) e.block(n.Body) e.loopDepth-- - // Right is evaluated outside the loop. - k := e.discardHole() - if len(ks) >= 2 { - if n.X.Type().IsArray() { - k = ks[1].note(n, "range") - } else { - k = ks[1].deref(n, "range-deref") - } + // X is evaluated outside the loop. + if n.X.Type().IsArray() { + k = k.note(n, "range") + } else { + k = k.deref(n, "range-deref") } e.expr(e.later(k), n.X) diff --git a/src/cmd/compile/internal/ir/fmt.go b/src/cmd/compile/internal/ir/fmt.go index b882979aa4..2b73c5ac1b 100644 --- a/src/cmd/compile/internal/ir/fmt.go +++ b/src/cmd/compile/internal/ir/fmt.go @@ -444,12 +444,15 @@ func stmtFmt(n Node, s fmt.State) { break } - if len(n.Vars) == 0 { - fmt.Fprintf(s, "for range %v { %v }", n.X, n.Body) - break + fmt.Fprint(s, "for") + if n.Key != nil { + fmt.Fprintf(s, " %v", n.Key) + if n.Value != nil { + fmt.Fprintf(s, ", %v", n.Value) + } + fmt.Fprint(s, " =") } - - fmt.Fprintf(s, "for %.v = range %v { %v }", n.Vars, n.X, n.Body) + fmt.Fprintf(s, " range %v { %v }", n.X, n.Body) case OSELECT: n := n.(*SelectStmt) diff --git a/src/cmd/compile/internal/ir/node_gen.go b/src/cmd/compile/internal/ir/node_gen.go index 7d3488f3fd..ecb39563c4 100644 --- a/src/cmd/compile/internal/ir/node_gen.go +++ b/src/cmd/compile/internal/ir/node_gen.go @@ -724,22 +724,23 @@ func (n *RangeStmt) Format(s fmt.State, verb rune) { FmtNode(n, s, verb) } func (n *RangeStmt) copy() Node { c := *n c.init = c.init.Copy() - c.Vars = c.Vars.Copy() c.Body = c.Body.Copy() return &c } func (n *RangeStmt) doChildren(do func(Node) error) error { var err error err = maybeDoList(n.init, err, do) - err = maybeDoList(n.Vars, err, do) err = maybeDo(n.X, err, do) + err = maybeDo(n.Key, err, do) + err = maybeDo(n.Value, err, do) err = maybeDoList(n.Body, err, do) return err } func (n *RangeStmt) editChildren(edit func(Node) Node) { editList(n.init, edit) - editList(n.Vars, edit) n.X = maybeEdit(n.X, edit) + n.Key = maybeEdit(n.Key, edit) + n.Value = maybeEdit(n.Value, edit) editList(n.Body, edit) } diff --git a/src/cmd/compile/internal/ir/stmt.go b/src/cmd/compile/internal/ir/stmt.go index c9988eba5c..453153c024 100644 --- a/src/cmd/compile/internal/ir/stmt.go +++ b/src/cmd/compile/internal/ir/stmt.go @@ -290,25 +290,24 @@ func NewLabelStmt(pos src.XPos, label *types.Sym) *LabelStmt { func (n *LabelStmt) Sym() *types.Sym { return n.Label } -// A RangeStmt is a range loop: for Vars = range X { Stmts } -// Op can be OFOR or OFORUNTIL (!Cond). +// A RangeStmt is a range loop: for Key, Value = range X { Body } type RangeStmt struct { miniStmt Label *types.Sym - Vars Nodes // TODO(rsc): Replace with Key, Value Node Def bool X Node + Key Node + Value Node Body Nodes HasBreak bool typ *types.Type // TODO(rsc): Remove - use X.Type() instead Prealloc *Name } -func NewRangeStmt(pos src.XPos, vars []Node, x Node, body []Node) *RangeStmt { - n := &RangeStmt{X: x} +func NewRangeStmt(pos src.XPos, key, value, x Node, body []Node) *RangeStmt { + n := &RangeStmt{X: x, Key: key, Value: value} n.pos = pos n.op = ORANGE - n.Vars.Set(vars) n.Body.Set(body) return n } diff --git a/src/cmd/compile/internal/noder/noder.go b/src/cmd/compile/internal/noder/noder.go index 68a01612dc..ad66b6c850 100644 --- a/src/cmd/compile/internal/noder/noder.go +++ b/src/cmd/compile/internal/noder/noder.go @@ -1172,10 +1172,14 @@ func (p *noder) forStmt(stmt *syntax.ForStmt) ir.Node { panic("unexpected RangeClause") } - n := ir.NewRangeStmt(p.pos(r), nil, p.expr(r.X), nil) + n := ir.NewRangeStmt(p.pos(r), nil, nil, p.expr(r.X), nil) if r.Lhs != nil { n.Def = r.Def - n.Vars.Set(p.assignList(r.Lhs, n, n.Def)) + lhs := p.assignList(r.Lhs, n, n.Def) + n.Key = lhs[0] + if len(lhs) > 1 { + n.Value = lhs[1] + } } n.Body.Set(p.blockStmt(stmt.Body)) p.closeAnotherScope() diff --git a/src/cmd/compile/internal/typecheck/iexport.go b/src/cmd/compile/internal/typecheck/iexport.go index 4cb943daaf..449d99266d 100644 --- a/src/cmd/compile/internal/typecheck/iexport.go +++ b/src/cmd/compile/internal/typecheck/iexport.go @@ -1143,7 +1143,7 @@ func (w *exportWriter) stmt(n ir.Node) { n := n.(*ir.RangeStmt) w.op(ir.ORANGE) w.pos(n.Pos()) - w.stmtList(n.Vars) + w.exprsOrNil(n.Key, n.Value) w.expr(n.X) w.stmtList(n.Body) diff --git a/src/cmd/compile/internal/typecheck/iimport.go b/src/cmd/compile/internal/typecheck/iimport.go index 221229571c..8285c418e9 100644 --- a/src/cmd/compile/internal/typecheck/iimport.go +++ b/src/cmd/compile/internal/typecheck/iimport.go @@ -1028,7 +1028,9 @@ func (r *importReader) node() ir.Node { return ir.NewForStmt(pos, init, cond, post, r.stmtList()) case ir.ORANGE: - return ir.NewRangeStmt(r.pos(), r.stmtList(), r.expr(), r.stmtList()) + pos := r.pos() + k, v := r.exprsOrNil() + return ir.NewRangeStmt(pos, k, v, r.expr(), r.stmtList()) case ir.OSELECT: pos := r.pos() diff --git a/src/cmd/compile/internal/typecheck/stmt.go b/src/cmd/compile/internal/typecheck/stmt.go index 133f93e53b..dfa224b318 100644 --- a/src/cmd/compile/internal/typecheck/stmt.go +++ b/src/cmd/compile/internal/typecheck/stmt.go @@ -19,19 +19,18 @@ func typecheckrangeExpr(n *ir.RangeStmt) { return } // delicate little dance. see typecheckas2 - ls := n.Vars - for i1, n1 := range ls { - if !ir.DeclaredBy(n1, n) { - ls[i1] = AssignExpr(ls[i1]) - } + if n.Key != nil && !ir.DeclaredBy(n.Key, n) { + n.Key = AssignExpr(n.Key) + } + if n.Value != nil && !ir.DeclaredBy(n.Value, n) { + n.Value = AssignExpr(n.Value) } - if t.IsPtr() && t.Elem().IsArray() { t = t.Elem() } n.SetType(t) - var t1, t2 *types.Type + var tk, tv *types.Type toomany := false switch t.Kind() { default: @@ -39,12 +38,12 @@ func typecheckrangeExpr(n *ir.RangeStmt) { return case types.TARRAY, types.TSLICE: - t1 = types.Types[types.TINT] - t2 = t.Elem() + tk = types.Types[types.TINT] + tv = t.Elem() case types.TMAP: - t1 = t.Key() - t2 = t.Elem() + tk = t.Key() + tv = t.Elem() case types.TCHAN: if !t.ChanDir().CanRecv() { @@ -52,61 +51,35 @@ func typecheckrangeExpr(n *ir.RangeStmt) { return } - t1 = t.Elem() - t2 = nil - if len(n.Vars) == 2 { + tk = t.Elem() + tv = nil + if n.Value != nil { toomany = true } case types.TSTRING: - t1 = types.Types[types.TINT] - t2 = types.RuneType + tk = types.Types[types.TINT] + tv = types.RuneType } - if len(n.Vars) > 2 || toomany { + if toomany { base.ErrorfAt(n.Pos(), "too many variables in range") } - var v1, v2 ir.Node - if len(n.Vars) != 0 { - v1 = n.Vars[0] - } - if len(n.Vars) > 1 { - v2 = n.Vars[1] - } - - // this is not only an optimization but also a requirement in the spec. - // "if the second iteration variable is the blank identifier, the range - // clause is equivalent to the same clause with only the first variable - // present." - if ir.IsBlank(v2) { - if v1 != nil { - n.Vars = []ir.Node{v1} - } - v2 = nil - } - - if v1 != nil { - if ir.DeclaredBy(v1, n) { - v1.SetType(t1) - } else if v1.Type() != nil { - if op, why := assignop(t1, v1.Type()); op == ir.OXXX { - base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t1, v1, why) + do := func(nn ir.Node, t *types.Type) { + if nn != nil { + if ir.DeclaredBy(nn, n) { + nn.SetType(t) + } else if nn.Type() != nil { + if op, why := assignop(t, nn.Type()); op == ir.OXXX { + base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t, nn, why) + } } + checkassign(n, nn) } - checkassign(n, v1) - } - - if v2 != nil { - if ir.DeclaredBy(v2, n) { - v2.SetType(t2) - } else if v2.Type() != nil { - if op, why := assignop(t2, v2.Type()); op == ir.OXXX { - base.ErrorfAt(n.Pos(), "cannot assign type %v to %L in range%s", t2, v2, why) - } - } - checkassign(n, v2) } + do(n.Key, tk) + do(n.Value, tv) } // type check assignment. @@ -399,11 +372,11 @@ func tcRange(n *ir.RangeStmt) { // second half of dance, the first half being typecheckrangeExpr n.SetTypecheck(1) - ls := n.Vars - for i1, n1 := range ls { - if n1.Typecheck() == 0 { - ls[i1] = AssignExpr(ls[i1]) - } + if n.Key != nil && n.Key.Typecheck() == 0 { + n.Key = AssignExpr(n.Key) + } + if n.Value != nil && n.Value.Typecheck() == 0 { + n.Value = AssignExpr(n.Value) } decldepth++ diff --git a/src/cmd/compile/internal/walk/order.go b/src/cmd/compile/internal/walk/order.go index de6a3807e6..1fcebf5194 100644 --- a/src/cmd/compile/internal/walk/order.go +++ b/src/cmd/compile/internal/walk/order.go @@ -848,7 +848,7 @@ func (o *orderState) stmt(n ir.Node) { base.Fatalf("order.stmt range %v", n.Type()) case types.TARRAY, types.TSLICE: - if len(n.Vars) < 2 || ir.IsBlank(n.Vars[1]) { + if n.Value == nil || ir.IsBlank(n.Value) { // for i := range x will only use x once, to compute len(x). // No need to copy it. break @@ -887,7 +887,8 @@ func (o *orderState) stmt(n ir.Node) { // hiter contains pointers and needs to be zeroed. n.Prealloc = o.newTemp(reflectdata.MapIterType(n.Type()), true) } - o.exprListInPlace(n.Vars) + n.Key = o.exprInPlace(n.Key) + n.Value = o.exprInPlace(n.Value) if orderBody { orderBlock(&n.Body, o.free) } diff --git a/src/cmd/compile/internal/walk/range.go b/src/cmd/compile/internal/walk/range.go index 98a3dc23f9..5ecd577f74 100644 --- a/src/cmd/compile/internal/walk/range.go +++ b/src/cmd/compile/internal/walk/range.go @@ -61,15 +61,7 @@ func walkRange(nrange *ir.RangeStmt) ir.Node { a := nrange.X lno := ir.SetPos(a) - var v1, v2 ir.Node - l := len(nrange.Vars) - if l > 0 { - v1 = nrange.Vars[0] - } - - if l > 1 { - v2 = nrange.Vars[1] - } + v1, v2 := nrange.Key, nrange.Value if ir.IsBlank(v2) { v2 = nil @@ -343,15 +335,11 @@ func isMapClear(n *ir.RangeStmt) bool { return false } - if n.Op() != ir.ORANGE || n.Type().Kind() != types.TMAP || len(n.Vars) != 1 { - return false - } - - k := n.Vars[0] - if k == nil || ir.IsBlank(k) { + if n.Op() != ir.ORANGE || n.Type().Kind() != types.TMAP || n.Key == nil || n.Value != nil { return false } + k := n.Key // Require k to be a new variable name. if !ir.DeclaredBy(k, n) { return false