cmd/compile: move sizeof tests for types structs to package types

Change-Id: I04cd4dd0ed55b88247a056b429fc496539cd0985
Reviewed-on: https://go-review.googlesource.com/39910
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

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

@@ -7,7 +7,6 @@
 package gc
 
 import (
-	"cmd/compile/internal/types"
 	"reflect"
 	"testing"
 	"unsafe"
@@ -27,21 +26,6 @@ func TestSizeof(t *testing.T) {
 		{Name{}, 36, 56},
 		{Param{}, 28, 56},
 		{Node{}, 84, 136},
-		// TODO(gri) test the ones below in the types package
-		{types.Sym{}, 60, 104},
-		{types.Type{}, 52, 88},
-		{types.MapType{}, 20, 40},
-		{types.ForwardType{}, 20, 32},
-		{types.FuncType{}, 28, 48},
-		{types.StructType{}, 12, 24},
-		{types.InterType{}, 4, 8},
-		{types.ChanType{}, 8, 16},
-		{types.ArrayType{}, 12, 16},
-		{types.DDDFieldType{}, 4, 8},
-		{types.FuncArgsType{}, 4, 8},
-		{types.ChanArgsType{}, 4, 8},
-		{types.PtrType{}, 4, 8},
-		{types.SliceType{}, 4, 8},
 	}
 
 	for _, tt := range tests {

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

@@ -0,0 +1,51 @@
+// Copyright 2017 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !nacl
+
+package types
+
+import (
+	"reflect"
+	"testing"
+	"unsafe"
+)
+
+// Assert that the size of important structures do not change unexpectedly.
+
+func TestSizeof(t *testing.T) {
+	const _64bit = unsafe.Sizeof(uintptr(0)) == 8
+
+	var tests = []struct {
+		val    interface{} // type as a value
+		_32bit uintptr     // size on 32bit platforms
+		_64bit uintptr     // size on 64bit platforms
+	}{
+		{Sym{}, 60, 104},
+		{Type{}, 52, 88},
+		{MapType{}, 20, 40},
+		{ForwardType{}, 20, 32},
+		{FuncType{}, 28, 48},
+		{StructType{}, 12, 24},
+		{InterType{}, 4, 8},
+		{ChanType{}, 8, 16},
+		{ArrayType{}, 12, 16},
+		{DDDFieldType{}, 4, 8},
+		{FuncArgsType{}, 4, 8},
+		{ChanArgsType{}, 4, 8},
+		{PtrType{}, 4, 8},
+		{SliceType{}, 4, 8},
+	}
+
+	for _, tt := range tests {
+		want := tt._32bit
+		if _64bit {
+			want = tt._64bit
+		}
+		got := reflect.TypeOf(tt.val).Size()
+		if want != got {
+			t.Errorf("unsafe.Sizeof(%T) = %d, want %d", tt.val, got, want)
+		}
+	}
+}