[dev.regabi] cmd/compile: remove Name.Typegen

Just directly set Type.Vargen when declaring defined types within a
function.

Change-Id: Idcc0007084a660ce1c39da4a3697e158a1c615b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/283212
Trust: Matthew Dempsky <mdempsky@google.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>

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

@@ -55,10 +55,6 @@ type Name struct {
 	// The function, method, or closure in which local variable or param is declared.
 	Curfn *Func
 
-	// Unique number for OTYPE names within a function.
-	// TODO(mdempsky): Remove completely.
-	Typegen int32
-
 	Ntype    Ntype
 	Heapaddr *Name // temp holding heap address of param
 

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

@@ -21,7 +21,7 @@ func TestSizeof(t *testing.T) {
 		_64bit uintptr     // size on 64bit platforms
 	}{
 		{Func{}, 184, 320},
-		{Name{}, 120, 216},
+		{Name{}, 116, 208},
 	}
 
 	for _, tt := range tests {

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

@@ -62,10 +62,6 @@ func Declare(n *ir.Name, ctxt ir.Class) {
 		if ir.CurFunc != nil && ctxt != ir.PFUNC && n.Op() == ir.ONAME {
 			ir.CurFunc.Dcl = append(ir.CurFunc.Dcl, n)
 		}
-		if n.Op() == ir.OTYPE {
-			declare_typegen++
-			n.Typegen = int32(declare_typegen)
-		}
 		types.Pushdcl(s)
 		n.Curfn = ir.CurFunc
 	}
@@ -308,10 +304,6 @@ func checkembeddedtype(t *types.Type) {
 	}
 }
 
-// declare individual names - var, typ, const
-
-var declare_typegen int
-
 func fakeRecvField() *types.Field {
 	return types.NewField(src.NoXPos, nil, types.FakeRecvType())
 }

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

@@ -1681,13 +1681,22 @@ func CheckMapKeys() {
 	mapqueue = nil
 }
 
+// typegen tracks the number of function-scoped defined types that
+// have been declared. It's used to generate unique linker symbols for
+// their runtime type descriptors.
+var typegen int32
+
 func typecheckdeftype(n *ir.Name) {
 	if base.EnableTrace && base.Flag.LowerT {
 		defer tracePrint("typecheckdeftype", n)(nil)
 	}
 
 	t := types.NewNamed(n)
-	t.Vargen = n.Typegen
+	if n.Curfn != nil {
+		typegen++
+		t.Vargen = typegen
+	}
+
 	if n.Pragma()&ir.NotInHeap != 0 {
 		t.SetNotInHeap(true)
 	}