4 files changed, 52 insertions, 15 deletions

diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go
index 66af2bf01c..9597aa893d 100644
--- a/src/cmd/compile/internal/gc/reflect.go
+++ b/src/cmd/compile/internal/gc/reflect.go
@@ -49,16 +49,7 @@ type Sig struct {
 	offset int32
 }
 
-// byMethodNameAndPackagePath sorts method signatures by name, then package path.
-type byMethodNameAndPackagePath []*Sig
-
-func (x byMethodNameAndPackagePath) Len() int      { return len(x) }
-func (x byMethodNameAndPackagePath) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
-func (x byMethodNameAndPackagePath) Less(i, j int) bool {
-	return siglt(x[i], x[j])
-}
-
-// siglt reports whether a < b
+// siglt sorts method signatures by name, then package path.
 func siglt(a, b *Sig) bool {
 	if a.name != b.name {
 		return a.name < b.name
@@ -382,7 +373,7 @@ func methods(t *types.Type) []*Sig {
 		}
 	}
 
-	sort.Sort(byMethodNameAndPackagePath(ms))
+	obj.SortSlice(ms, func(i, j int) bool { return siglt(ms[i], ms[j]) })
 	return ms
 }
 
diff --git a/src/cmd/compile/internal/gc/reflect_test.go b/src/cmd/compile/internal/gc/reflect_test.go
index ad3cad73c0..fe6dcf0d2e 100644
--- a/src/cmd/compile/internal/gc/reflect_test.go
+++ b/src/cmd/compile/internal/gc/reflect_test.go
@@ -6,12 +6,12 @@ package gc
 
 import (
 	"cmd/compile/internal/types"
+	"cmd/internal/obj"
 	"reflect"
-	"sort"
 	"testing"
 )
 
-func TestSortingByMethodNameAndPackagePath(t *testing.T) {
+func TestSortingBySigLT(t *testing.T) {
 	data := []*Sig{
 		&Sig{name: "b", pkg: &types.Pkg{Path: "abc"}},
 		&Sig{name: "b", pkg: nil},
@@ -38,11 +38,10 @@ func TestSortingByMethodNameAndPackagePath(t *testing.T) {
 	if reflect.DeepEqual(data, want) {
 		t.Fatal("data must be shuffled")
 	}
-	sort.Sort(byMethodNameAndPackagePath(data))
+	obj.SortSlice(data, func(i, j int) bool { return siglt(data[i], data[j]) })
 	if !reflect.DeepEqual(data, want) {
 		t.Logf("want: %#v", want)
 		t.Logf("data: %#v", data)
 		t.Errorf("sorting failed")
 	}
-
 }
diff --git a/src/cmd/internal/obj/bootstrap.go b/src/cmd/internal/obj/bootstrap.go
new file mode 100644
index 0000000000..42835e1d9d
--- /dev/null
+++ b/src/cmd/internal/obj/bootstrap.go
@@ -0,0 +1,34 @@
+// 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 !go1.8
+
+package obj
+
+import (
+	"reflect"
+	"sort"
+)
+
+func SortSlice(slice interface{}, less func(i, j int) bool) {
+	val := reflect.ValueOf(slice)
+	tmp := reflect.New(val.Type().Elem()).Elem()
+	x := sliceByFn{val: val, tmp: tmp, less: less}
+	sort.Sort(x)
+}
+
+type sliceByFn struct {
+	val  reflect.Value
+	tmp  reflect.Value
+	less func(i, j int) bool
+}
+
+func (x sliceByFn) Len() int           { return x.val.Len() }
+func (x sliceByFn) Less(i, j int) bool { return x.less(i, j) }
+func (x sliceByFn) Swap(i, j int) {
+	a, b := x.val.Index(i), x.val.Index(j)
+	x.tmp.Set(a)
+	a.Set(b)
+	b.Set(x.tmp)
+}
diff --git a/src/cmd/internal/obj/sort.go b/src/cmd/internal/obj/sort.go
new file mode 100644
index 0000000000..0cb801ee98
--- /dev/null
+++ b/src/cmd/internal/obj/sort.go
@@ -0,0 +1,13 @@
+// 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 go1.8
+
+package obj
+
+import "sort"
+
+func SortSlice(slice interface{}, less func(i, j int) bool) {
+	sort.Slice(slice, less)
+}