cmd/compile/internal/gc: refactor ODCLFUNC creation

Extract out some common boiler plate logic.

Passes toolstash-check -all.

Change-Id: Iddc8a733af8262558f56d13c91d9c27ee0d61330
Reviewed-on: https://go-review.googlesource.com/40253
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/compile/internal/gc/alg.go

@@ -194,13 +194,7 @@ func genhash(sym *types.Sym, t *types.Type) {
 	types.Markdcl(lineno)
 
 	// func sym(p *T, h uintptr) uintptr
-	fn := nod(ODCLFUNC, nil, nil)
-
-	fn.Func.Nname = newname(sym)
-	fn.Func.Nname.Class = PFUNC
 	tfn := nod(OTFUNC, nil, nil)
-	fn.Func.Nname.Name.Param.Ntype = tfn
-
 	n := namedfield("p", types.NewPtr(t))
 	tfn.List.Append(n)
 	np := n.Left
@@ -210,8 +204,7 @@ func genhash(sym *types.Sym, t *types.Type) {
 	n = anonfield(types.Types[TUINTPTR]) // return value
 	tfn.Rlist.Append(n)
 
-	funchdr(fn)
-	fn.Func.Nname.Name.Param.Ntype = typecheck(fn.Func.Nname.Name.Param.Ntype, Etype)
+	fn := dclfunc(sym, tfn)
 
 	// genhash is only called for types that have equality but
 	// cannot be handled by the standard algorithms,
@@ -372,13 +365,7 @@ func geneq(sym *types.Sym, t *types.Type) {
 	types.Markdcl(lineno)
 
 	// func sym(p, q *T) bool
-	fn := nod(ODCLFUNC, nil, nil)
-
-	fn.Func.Nname = newname(sym)
-	fn.Func.Nname.Class = PFUNC
 	tfn := nod(OTFUNC, nil, nil)
-	fn.Func.Nname.Name.Param.Ntype = tfn
-
 	n := namedfield("p", types.NewPtr(t))
 	tfn.List.Append(n)
 	np := n.Left
@@ -388,8 +375,7 @@ func geneq(sym *types.Sym, t *types.Type) {
 	n = anonfield(types.Types[TBOOL])
 	tfn.Rlist.Append(n)
 
-	funchdr(fn)
-	fn.Func.Nname.Name.Param.Ntype = typecheck(fn.Func.Nname.Name.Param.Ntype, Etype)
+	fn := dclfunc(sym, tfn)
 
 	// geneq is only called for types that have equality but
 	// cannot be handled by the standard algorithms,

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

@@ -1100,6 +1100,21 @@ func makefuncsym(s *types.Sym) {
 	}
 }
 
+func dclfunc(sym *types.Sym, tfn *Node) *Node {
+	if tfn.Op != OTFUNC {
+		Fatalf("expected OTFUNC node, got %v", tfn)
+	}
+
+	fn := nod(ODCLFUNC, nil, nil)
+	fn.Func.Nname = newname(sym)
+	fn.Func.Nname.Name.Defn = fn
+	fn.Func.Nname.Name.Param.Ntype = tfn
+	declare(fn.Func.Nname, PFUNC)
+	funchdr(fn)
+	fn.Func.Nname.Name.Param.Ntype = typecheck(fn.Func.Nname.Name.Param.Ntype, Etype)
+	return fn
+}
+
 type nowritebarrierrecChecker struct {
 	curfn  *Node
 	stable bool

src/cmd/compile/internal/gc/init.go

@@ -86,13 +86,8 @@ func fninit(n []*Node) {
 	addvar(gatevar, types.Types[TUINT8], PEXTERN)
 
 	// (2)
-	fn := nod(ODCLFUNC, nil, nil)
 	initsym := lookup("init")
-	fn.Func.Nname = newname(initsym)
-	fn.Func.Nname.Name.Defn = fn
-	fn.Func.Nname.Name.Param.Ntype = nod(OTFUNC, nil, nil)
-	declare(fn.Func.Nname, PFUNC)
-	funchdr(fn)
+	fn := dclfunc(initsym, nod(OTFUNC, nil, nil))
 
 	// (3)
 	a := nod(OIF, nil, nil)

src/cmd/compile/internal/gc/subr.go

@@ -1710,14 +1710,9 @@ func genwrapper(rcvr *types.Type, method *types.Field, newnam *types.Sym, iface
 	t.List.Set(append(l, in...))
 	t.Rlist.Set(out)
 
-	fn := nod(ODCLFUNC, nil, nil)
+	fn := dclfunc(newnam, t)
 	fn.Func.SetDupok(true)
-	fn.Func.Nname = newname(newnam)
-	fn.Func.Nname.Name.Defn = fn
-	fn.Func.Nname.Name.Param.Ntype = t
 	fn.Func.Nname.Sym.SetExported(true) // prevent export; see closure.go
-	declare(fn.Func.Nname, PFUNC)
-	funchdr(fn)
 
 	// arg list
 	var args []*Node

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

@@ -3652,17 +3652,12 @@ func walkprintfunc(n *Node, init *Nodes) *Node {
 		printargs = append(printargs, a.Left)
 	}
 
-	fn := nod(ODCLFUNC, nil, nil)
-	walkprintfunc_prgen++
-	buf = fmt.Sprintf("print·%d", walkprintfunc_prgen)
-	fn.Func.Nname = newname(lookup(buf))
-	fn.Func.Nname.Name.Defn = fn
-	fn.Func.Nname.Name.Param.Ntype = t
-	declare(fn.Func.Nname, PFUNC)
-
 	oldfn := Curfn
 	Curfn = nil
-	funchdr(fn)
+
+	walkprintfunc_prgen++
+	sym := lookupN("print·%d", walkprintfunc_prgen)
+	fn := dclfunc(sym, t)
 
 	a = nod(n.Op, nil, nil)
 	a.List.Set(printargs)