[dev.regabi] cmd/compile: simplify ir.Func somewhat

Two simplifications:

1. Statements (including ODCLFUNC) don't have types, and the
Func.Nname already has a type. There's no need for a second one.
However, there is a lot of code that expects to be able to call
Func.Type, so leave a forwarding method, like with Sym and Linksym.

2. Inline and remove ir.NewFuncNameAt. It doesn't really save any
code, and it's only used a handful of places.

Passes toolstash -cmp.

Change-Id: I51acaa341897dae0fcdf2fa576a10174a2ae4d1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/280648
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

src/cmd/compile/internal/ir/func.go

@@ -49,7 +49,6 @@ import (
 // pointer from the Func back to the OCALLPART.
 type Func struct {
 	miniNode
-	typ  *types.Type
 	Body Nodes
 	Iota int64
 
@@ -116,9 +115,7 @@ func NewFunc(pos src.XPos) *Func {
 
 func (f *Func) isStmt() {}
 
-func (f *Func) Type() *types.Type     { return f.typ }
-func (f *Func) SetType(x *types.Type) { f.typ = x }
-
+func (f *Func) Type() *types.Type  { return f.Nname.Type() }
 func (f *Func) Sym() *types.Sym    { return f.Nname.Sym() }
 func (f *Func) Linksym() *obj.LSym { return f.Nname.Linksym() }
 
@@ -236,17 +233,6 @@ func FuncSymName(s *types.Sym) string {
 	return s.Name + "·f"
 }
 
-// NewFuncNameAt generates a new name node for a function or method.
-func NewFuncNameAt(pos src.XPos, s *types.Sym, fn *Func) *Name {
-	if fn.Nname != nil {
-		base.Fatalf("newFuncName - already have name")
-	}
-	n := NewNameAt(pos, s)
-	n.SetFunc(fn)
-	fn.Nname = n
-	return n
-}
-
 // MarkFunc marks a node as a function.
 func MarkFunc(n *Name) {
 	if n.Op() != ONAME || n.Class_ != Pxxx {

src/cmd/compile/internal/ir/sizeof_test.go

@@ -20,7 +20,7 @@ func TestSizeof(t *testing.T) {
 		_32bit uintptr     // size on 32bit platforms
 		_64bit uintptr     // size on 64bit platforms
 	}{
-		{Func{}, 200, 352},
+		{Func{}, 196, 344},
 		{Name{}, 132, 232},
 	}
 

src/cmd/compile/internal/noder/noder.go

@@ -524,7 +524,8 @@ func (p *noder) funcDecl(fun *syntax.FuncDecl) ir.Node {
 		name = ir.BlankNode.Sym() // filled in by typecheckfunc
 	}
 
-	f.Nname = ir.NewFuncNameAt(p.pos(fun.Name), name, f)
+	f.Nname = ir.NewNameAt(p.pos(fun.Name), name)
+	f.Nname.Func = f
 	f.Nname.Defn = f
 	f.Nname.Ntype = t
 
@@ -1742,7 +1743,9 @@ func (p *noder) funcLit(expr *syntax.FuncLit) ir.Node {
 
 	fn := ir.NewFunc(p.pos(expr))
 	fn.SetIsHiddenClosure(ir.CurFunc != nil)
-	fn.Nname = ir.NewFuncNameAt(p.pos(expr), ir.BlankNode.Sym(), fn) // filled in by typecheckclosure
+
+	fn.Nname = ir.NewNameAt(p.pos(expr), ir.BlankNode.Sym()) // filled in by typecheckclosure
+	fn.Nname.Func = fn
 	fn.Nname.Ntype = xtype
 	fn.Nname.Defn = fn
 

src/cmd/compile/internal/typecheck/dcl.go

@@ -23,7 +23,8 @@ func DeclFunc(sym *types.Sym, tfn ir.Ntype) *ir.Func {
 	}
 
 	fn := ir.NewFunc(base.Pos)
-	fn.Nname = ir.NewFuncNameAt(base.Pos, sym, fn)
+	fn.Nname = ir.NewNameAt(base.Pos, sym)
+	fn.Nname.Func = fn
 	fn.Nname.Defn = fn
 	fn.Nname.Ntype = tfn
 	ir.MarkFunc(fn.Nname)

src/cmd/compile/internal/typecheck/export.go

@@ -31,12 +31,8 @@ func importconst(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type, val
 // ipkg is the package being imported
 func importfunc(ipkg *types.Pkg, pos src.XPos, s *types.Sym, t *types.Type) *ir.Name {
 	n := importobj(ipkg, pos, s, ir.ONAME, ir.PFUNC, t)
-
-	fn := ir.NewFunc(pos)
-	fn.SetType(t)
-	n.SetFunc(fn)
-	fn.Nname = n
-
+	n.Func = ir.NewFunc(pos)
+	n.Func.Nname = n
 	return n
 }
 

src/cmd/compile/internal/typecheck/func.go

@@ -409,7 +409,6 @@ func tcFunc(n *ir.Func) {
 	if t == nil {
 		return
 	}
-	n.SetType(t)
 	rcvr := t.Recv()
 	if rcvr != nil && n.Shortname != nil {
 		m := addmethod(n, n.Shortname, t, true, n.Pragma&ir.Nointerface != 0)

src/cmd/compile/internal/typecheck/iimport.go

@@ -331,12 +331,13 @@ func (r *importReader) doDecl(sym *types.Sym) *ir.Name {
 			recv := r.param()
 			mtyp := r.signature(recv)
 
-			fn := ir.NewFunc(mpos)
-			fn.SetType(mtyp)
-			m := ir.NewFuncNameAt(mpos, ir.MethodSym(recv.Type, msym), fn)
-			m.SetType(mtyp)
-			m.Class_ = ir.PFUNC
 			// methodSym already marked m.Sym as a function.
+			m := ir.NewNameAt(mpos, ir.MethodSym(recv.Type, msym))
+			m.Class_ = ir.PFUNC
+			m.SetType(mtyp)
+
+			m.Func = ir.NewFunc(mpos)
+			m.Func.Nname = m
 
 			f := types.NewField(mpos, msym, mtyp)
 			f.Nname = m

src/cmd/compile/internal/walk/closure.go

@@ -67,7 +67,7 @@ func Closure(fn *ir.Func) {
 		}
 
 		types.CalcSize(f.Type())
-		fn.SetType(f.Type()) // update type of ODCLFUNC
+		fn.Nname.SetType(f.Type()) // update type of ODCLFUNC
 	} else {
 		// The closure is not called, so it is going to stay as closure.
 		var body []ir.Node