[dev.regabi] cmd/compile: add custom type syntax Node implementations

The type syntax is reused to stand in for the actual type once typechecked,
to avoid updating all the possible references to the original type syntax.
So all these implementations allow changing their Op from the raw syntax
like OTMAP to the finished form OTYPE, even though obviously the
representation does not change.

Passes buildall w/ toolstash -cmp.

Change-Id: I4acca1a5b35fa2f48ee08e8f1e5a330a004c284b
Reviewed-on: https://go-review.googlesource.com/c/go/+/274103
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

1 files changed, 50 insertions, 52 deletions

diff --git a/src/cmd/compile/internal/gc/noder.go b/src/cmd/compile/internal/gc/noder.go
index 1c433b5d30..e6c78d1afb 100644
--- a/src/cmd/compile/internal/gc/noder.go
+++ b/src/cmd/compile/internal/gc/noder.go
@@ -412,7 +412,7 @@ func (p *noder) varDecl(decl *syntax.VarDecl) []ir.Node {
 // constant declarations are handled correctly (e.g., issue 15550).
 type constState struct {
 	group  *syntax.Group
-	typ    ir.Node
+	typ    ir.Ntype
 	values []ir.Node
 	iota   int64
 }
@@ -578,18 +578,18 @@ func (p *noder) funcDecl(fun *syntax.FuncDecl) ir.Node {
 	return f
 }
 
-func (p *noder) signature(recv *syntax.Field, typ *syntax.FuncType) ir.Node {
-	n := p.nod(typ, ir.OTFUNC, nil, nil)
+func (p *noder) signature(recv *syntax.Field, typ *syntax.FuncType) *ir.FuncType {
+	var rcvr *ir.Field
 	if recv != nil {
-		n.SetLeft(p.param(recv, false, false))
+		rcvr = p.param(recv, false, false)
 	}
-	n.PtrList().Set(p.params(typ.ParamList, true))
-	n.PtrRlist().Set(p.params(typ.ResultList, false))
-	return n
+	return ir.NewFuncType(p.pos(typ), rcvr,
+		p.params(typ.ParamList, true),
+		p.params(typ.ResultList, false))
 }
 
-func (p *noder) params(params []*syntax.Field, dddOk bool) []ir.Node {
-	nodes := make([]ir.Node, 0, len(params))
+func (p *noder) params(params []*syntax.Field, dddOk bool) []*ir.Field {
+	nodes := make([]*ir.Field, 0, len(params))
 	for i, param := range params {
 		p.setlineno(param)
 		nodes = append(nodes, p.param(param, dddOk, i+1 == len(params)))
@@ -597,17 +597,17 @@ func (p *noder) params(params []*syntax.Field, dddOk bool) []ir.Node {
 	return nodes
 }
 
-func (p *noder) param(param *syntax.Field, dddOk, final bool) ir.Node {
+func (p *noder) param(param *syntax.Field, dddOk, final bool) *ir.Field {
 	var name *types.Sym
 	if param.Name != nil {
 		name = p.name(param.Name)
 	}
 
 	typ := p.typeExpr(param.Type)
-	n := p.nodSym(param, ir.ODCLFIELD, typ, name)
+	n := ir.NewField(p.pos(param), name, typ, nil)
 
 	// rewrite ...T parameter
-	if typ.Op() == ir.ODDD {
+	if typ, ok := typ.(*ir.SliceType); ok && typ.DDD {
 		if !dddOk {
 			// We mark these as syntax errors to get automatic elimination
 			// of multiple such errors per line (see ErrorfAt in subr.go).
@@ -619,13 +619,8 @@ func (p *noder) param(param *syntax.Field, dddOk, final bool) ir.Node {
 				p.errorAt(param.Name.Pos(), "syntax error: cannot use ... with non-final parameter %s", param.Name.Value)
 			}
 		}
-		typ.SetOp(ir.OTARRAY)
-		typ.SetRight(typ.Left())
-		typ.SetLeft(nil)
-		n.SetIsDDD(true)
-		if n.Left() != nil {
-			n.Left().SetIsDDD(true)
-		}
+		typ.DDD = false
+		n.IsDDD = true
 	}
 
 	return n
@@ -727,14 +722,14 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 		var len ir.Node
 		if expr.Len != nil {
 			len = p.expr(expr.Len)
-		} else {
-			len = p.nod(expr, ir.ODDD, nil, nil)
 		}
-		return p.nod(expr, ir.OTARRAY, len, p.typeExpr(expr.Elem))
+		return ir.NewArrayType(p.pos(expr), len, p.typeExpr(expr.Elem))
 	case *syntax.SliceType:
-		return p.nod(expr, ir.OTARRAY, nil, p.typeExpr(expr.Elem))
+		return ir.NewSliceType(p.pos(expr), p.typeExpr(expr.Elem))
 	case *syntax.DotsType:
-		return p.nod(expr, ir.ODDD, p.typeExpr(expr.Elem), nil)
+		t := ir.NewSliceType(p.pos(expr), p.typeExpr(expr.Elem))
+		t.DDD = true
+		return t
 	case *syntax.StructType:
 		return p.structType(expr)
 	case *syntax.InterfaceType:
@@ -742,11 +737,11 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 	case *syntax.FuncType:
 		return p.signature(nil, expr)
 	case *syntax.MapType:
-		return p.nod(expr, ir.OTMAP, p.typeExpr(expr.Key), p.typeExpr(expr.Value))
+		return ir.NewMapType(p.pos(expr),
+			p.typeExpr(expr.Key), p.typeExpr(expr.Value))
 	case *syntax.ChanType:
-		n := p.nod(expr, ir.OTCHAN, p.typeExpr(expr.Elem), nil)
-		n.SetTChanDir(p.chanDir(expr.Dir))
-		return n
+		return ir.NewChanType(p.pos(expr),
+			p.typeExpr(expr.Elem), p.chanDir(expr.Dir))
 
 	case *syntax.TypeSwitchGuard:
 		n := p.nod(expr, ir.OTYPESW, nil, p.expr(expr.X))
@@ -837,14 +832,21 @@ func (p *noder) sum(x syntax.Expr) ir.Node {
 	return n
 }
 
-func (p *noder) typeExpr(typ syntax.Expr) ir.Node {
+func (p *noder) typeExpr(typ syntax.Expr) ir.Ntype {
 	// TODO(mdempsky): Be stricter? typecheck should handle errors anyway.
-	return p.expr(typ)
+	n := p.expr(typ)
+	if n == nil {
+		return nil
+	}
+	if _, ok := n.(ir.Ntype); !ok {
+		ir.Dump("NOT NTYPE", n)
+	}
+	return n.(ir.Ntype)
 }
 
-func (p *noder) typeExprOrNil(typ syntax.Expr) ir.Node {
+func (p *noder) typeExprOrNil(typ syntax.Expr) ir.Ntype {
 	if typ != nil {
-		return p.expr(typ)
+		return p.typeExpr(typ)
 	}
 	return nil
 }
@@ -862,47 +864,43 @@ func (p *noder) chanDir(dir syntax.ChanDir) types.ChanDir {
 }
 
 func (p *noder) structType(expr *syntax.StructType) ir.Node {
-	l := make([]ir.Node, 0, len(expr.FieldList))
+	l := make([]*ir.Field, 0, len(expr.FieldList))
 	for i, field := range expr.FieldList {
 		p.setlineno(field)
-		var n ir.Node
+		var n *ir.Field
 		if field.Name == nil {
 			n = p.embedded(field.Type)
 		} else {
-			n = p.nodSym(field, ir.ODCLFIELD, p.typeExpr(field.Type), p.name(field.Name))
+			n = ir.NewField(p.pos(field), p.name(field.Name), p.typeExpr(field.Type), nil)
 		}
 		if i < len(expr.TagList) && expr.TagList[i] != nil {
-			n.SetOpt(constant.StringVal(p.basicLit(expr.TagList[i])))
+			n.Note = constant.StringVal(p.basicLit(expr.TagList[i]))
 		}
 		l = append(l, n)
 	}
 
 	p.setlineno(expr)
-	n := p.nod(expr, ir.OTSTRUCT, nil, nil)
-	n.PtrList().Set(l)
-	return n
+	return ir.NewStructType(p.pos(expr), l)
 }
 
 func (p *noder) interfaceType(expr *syntax.InterfaceType) ir.Node {
-	l := make([]ir.Node, 0, len(expr.MethodList))
+	l := make([]*ir.Field, 0, len(expr.MethodList))
 	for _, method := range expr.MethodList {
 		p.setlineno(method)
-		var n ir.Node
+		var n *ir.Field
 		if method.Name == nil {
-			n = p.nodSym(method, ir.ODCLFIELD, importName(p.packname(method.Type)), nil)
+			n = ir.NewField(p.pos(method), nil, importName(p.packname(method.Type)).(ir.Ntype), nil)
 		} else {
 			mname := p.name(method.Name)
-			sig := p.typeExpr(method.Type)
-			sig.SetLeft(fakeRecv())
-			n = p.nodSym(method, ir.ODCLFIELD, sig, mname)
+			sig := p.typeExpr(method.Type).(*ir.FuncType)
+			sig.Recv = fakeRecv()
+			n = ir.NewField(p.pos(method), mname, sig, nil)
 			ifacedcl(n)
 		}
 		l = append(l, n)
 	}
 
-	n := p.nod(expr, ir.OTINTER, nil, nil)
-	n.PtrList().Set(l)
-	return n
+	return ir.NewInterfaceType(p.pos(expr), l)
 }
 
 func (p *noder) packname(expr syntax.Expr) *types.Sym {
@@ -934,7 +932,7 @@ func (p *noder) packname(expr syntax.Expr) *types.Sym {
 	panic(fmt.Sprintf("unexpected packname: %#v", expr))
 }
 
-func (p *noder) embedded(typ syntax.Expr) ir.Node {
+func (p *noder) embedded(typ syntax.Expr) *ir.Field {
 	op, isStar := typ.(*syntax.Operation)
 	if isStar {
 		if op.Op != syntax.Mul || op.Y != nil {
@@ -944,11 +942,11 @@ func (p *noder) embedded(typ syntax.Expr) ir.Node {
 	}
 
 	sym := p.packname(typ)
-	n := p.nodSym(typ, ir.ODCLFIELD, importName(sym), lookup(sym.Name))
-	n.SetEmbedded(true)
+	n := ir.NewField(p.pos(typ), lookup(sym.Name), importName(sym).(ir.Ntype), nil)
+	n.Embedded = true
 
 	if isStar {
-		n.SetLeft(p.nod(op, ir.ODEREF, n.Left(), nil))
+		n.Ntype = ir.NewStarExpr(p.pos(op), n.Ntype)
 	}
 	return n
 }