1 files changed, 462 insertions, 0 deletions
diff --git a/test/escape_reflect.go b/test/escape_reflect.go
new file mode 100644
index 0000000..b2d674a
--- /dev/null
+++ b/test/escape_reflect.go
@@ -0,0 +1,462 @@
+// errorcheck -0 -m -l
+
+// Copyright 2022 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.
+
+// Test escape analysis for reflect Value operations.
+
+package escape
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+var sink interface{}
+
+func typ(x int) any {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Type()
+}
+
+func kind(x int) reflect.Kind {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Kind()
+}
+
+func int1(x int) int {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return int(v.Int())
+}
+
+func ptr(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0"
+	v := reflect.ValueOf(x)
+	return (*int)(v.UnsafePointer())
+}
+
+func bytes1(x []byte) byte { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Bytes()[0]
+}
+
+// Unfortunate: should only escape content. x (the interface storage) should not escape.
+func bytes2(x []byte) []byte { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Bytes()
+}
+
+func string1(x string) string { // ERROR "leaking param: x to result ~r0 level=0"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.String()
+}
+
+func string2(x int) string {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.String()
+}
+
+// Unfortunate: should only escape to result.
+func interface1(x any) any { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x)
+	return v.Interface()
+}
+
+func interface2(x int) any {
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Interface()
+}
+
+// Unfortunate: should not escape.
+func interface3(x int) int {
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Interface().(int)
+}
+
+// Unfortunate: should only escape to result.
+func interface4(x *int) any { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x)
+	return v.Interface()
+}
+
+func addr(x *int) reflect.Value { // ERROR "leaking param: x to result ~r0 level=0"
+	v := reflect.ValueOf(x).Elem()
+	return v.Addr()
+}
+
+// functions returning pointer as uintptr have to escape.
+func uintptr1(x *int) uintptr { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x)
+	return v.Pointer()
+}
+
+func unsafeaddr(x *int) uintptr { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x).Elem()
+	return v.UnsafeAddr()
+}
+
+func ifacedata(x any) [2]uintptr { // ERROR "moved to heap: x"
+	v := reflect.ValueOf(&x).Elem()
+	return v.InterfaceData()
+}
+
+func can(x int) bool {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.CanAddr() || v.CanInt() || v.CanSet() || v.CanInterface()
+}
+
+func is(x int) bool {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.IsValid() || v.IsNil() || v.IsZero()
+}
+
+func is2(x [2]int) bool {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.IsValid() || v.IsNil() || v.IsZero()
+}
+
+func is3(x struct { a, b int }) bool {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.IsValid() || v.IsNil() || v.IsZero()
+}
+
+func overflow(x int) bool {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.OverflowInt(1 << 62)
+}
+
+func len1(x []int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Len()
+}
+
+func len2(x [3]int) int {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Len()
+}
+
+func len3(x string) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Len()
+}
+
+func len4(x map[int]int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x)
+	return v.Len()
+}
+
+func len5(x chan int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x)
+	return v.Len()
+}
+
+func cap1(x []int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Cap()
+}
+
+func cap2(x [3]int) int {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Cap()
+}
+
+func cap3(x chan int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x)
+	return v.Cap()
+}
+
+func setlen(x *[]int, n int) { // ERROR "x does not escape"
+	v := reflect.ValueOf(x).Elem()
+	v.SetLen(n)
+}
+
+func setcap(x *[]int, n int) { // ERROR "x does not escape"
+	v := reflect.ValueOf(x).Elem()
+	v.SetCap(n)
+}
+
+// Unfortunate: x doesn't need to escape to heap, just to result.
+func slice1(x []byte) []byte { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Slice(1, 2).Bytes()
+}
+
+// Unfortunate: x doesn't need to escape to heap, just to result.
+func slice2(x string) string { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Slice(1, 2).String()
+}
+
+func slice3(x [10]byte) []byte {
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Slice(1, 2).Bytes()
+}
+
+func elem1(x *int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x)
+	return int(v.Elem().Int())
+}
+
+func elem2(x *string) string { // ERROR "leaking param: x to result ~r0 level=1"
+	v := reflect.ValueOf(x)
+	return string(v.Elem().String())
+}
+
+type S struct {
+	A int
+	B *int
+	C string
+}
+
+func (S) M() {}
+
+func field1(x S) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return int(v.Field(0).Int())
+}
+
+func field2(x S) string { // ERROR "leaking param: x to result ~r0 level=0"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Field(2).String()
+}
+
+func numfield(x S) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.NumField()
+}
+
+func index1(x []int) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return int(v.Index(0).Int())
+}
+
+// Unfortunate: should only leak content (level=1)
+func index2(x []string) string { // ERROR "leaking param: x to result ~r0 level=0"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Index(0).String()
+}
+
+func index3(x [3]int) int {
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return int(v.Index(0).Int())
+}
+
+func index4(x [3]string) string { // ERROR "leaking param: x to result ~r0 level=0"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.Index(0).String()
+}
+
+func index5(x string) byte { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return byte(v.Index(0).Uint())
+}
+
+// Unfortunate: x (the interface storage) doesn't need to escape as the function takes a scalar arg.
+func call1(f func(int), x int) { // ERROR "leaking param: f$"
+	fv := reflect.ValueOf(f)
+	v := reflect.ValueOf(x)     // ERROR "x escapes to heap"
+	fv.Call([]reflect.Value{v}) // ERROR "\[\]reflect\.Value{\.\.\.} does not escape"
+}
+
+func call2(f func(*int), x *int) { // ERROR "leaking param: f$" "leaking param: x$"
+	fv := reflect.ValueOf(f)
+	v := reflect.ValueOf(x)
+	fv.Call([]reflect.Value{v}) // ERROR "\[\]reflect.Value{\.\.\.} does not escape"
+}
+
+func method(x S) reflect.Value { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Method(0)
+}
+
+func nummethod(x S) int { // ERROR "x does not escape"
+	v := reflect.ValueOf(x) // ERROR "x does not escape"
+	return v.NumMethod()
+}
+
+// Unfortunate: k doesn't need to escape.
+func mapindex(m map[string]string, k string) string { // ERROR "m does not escape" "leaking param: k$"
+	mv := reflect.ValueOf(m)
+	kv := reflect.ValueOf(k) // ERROR "k escapes to heap"
+	return mv.MapIndex(kv).String()
+}
+
+func mapkeys(m map[string]string) []reflect.Value { // ERROR "m does not escape"
+	mv := reflect.ValueOf(m)
+	return mv.MapKeys()
+}
+
+func mapiter1(m map[string]string) *reflect.MapIter { // ERROR "leaking param: m$"
+	mv := reflect.ValueOf(m)
+	return mv.MapRange()
+}
+
+func mapiter2(m map[string]string) string { // ERROR "leaking param: m$"
+	mv := reflect.ValueOf(m)
+	it := mv.MapRange()
+	if it.Next() {
+		return it.Key().String()
+	}
+	return ""
+}
+
+func mapiter3(m map[string]string, it *reflect.MapIter) { // ERROR "leaking param: m$" "it does not escape"
+	mv := reflect.ValueOf(m)
+	it.Reset(mv)
+}
+
+func recv1(ch chan string) string { // ERROR "ch does not escape"
+	v := reflect.ValueOf(ch)
+	r, _ := v.Recv()
+	return r.String()
+}
+
+func recv2(ch chan string) string { // ERROR "ch does not escape"
+	v := reflect.ValueOf(ch)
+	r, _ := v.TryRecv()
+	return r.String()
+}
+
+// Unfortunate: x (the interface storage) doesn't need to escape.
+func send1(ch chan string, x string) { // ERROR "ch does not escape" "leaking param: x$"
+	vc := reflect.ValueOf(ch)
+	vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	vc.Send(vx)
+}
+
+// Unfortunate: x (the interface storage) doesn't need to escape.
+func send2(ch chan string, x string) bool { // ERROR "ch does not escape" "leaking param: x$"
+	vc := reflect.ValueOf(ch)
+	vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return vc.TrySend(vx)
+}
+
+func close1(ch chan string) { // ERROR "ch does not escape"
+	v := reflect.ValueOf(ch)
+	v.Close()
+}
+
+func select1(ch chan string) string { // ERROR "leaking param: ch$"
+	v := reflect.ValueOf(ch)
+	cas := reflect.SelectCase{Dir: reflect.SelectRecv, Chan: v}
+	_, r, _ := reflect.Select([]reflect.SelectCase{cas}) // ERROR "\[\]reflect.SelectCase{...} does not escape"
+	return r.String()
+}
+
+// Unfortunate: x (the interface storage) doesn't need to escape.
+func select2(ch chan string, x string) { // ERROR "leaking param: ch$" "leaking param: x$"
+	vc := reflect.ValueOf(ch)
+	vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	cas := reflect.SelectCase{Dir: reflect.SelectSend, Chan: vc, Send: vx}
+	reflect.Select([]reflect.SelectCase{cas}) // ERROR "\[\]reflect.SelectCase{...} does not escape"
+}
+
+var (
+	intTyp    = reflect.TypeOf(int(0))     // ERROR "int\(0\) does not escape"
+	uintTyp   = reflect.TypeOf(uint(0))    // ERROR "uint\(0\) does not escape"
+	stringTyp = reflect.TypeOf(string("")) // ERROR "string\(.*\) does not escape"
+	bytesTyp  = reflect.TypeOf([]byte{})   // ERROR "\[\]byte{} does not escape"
+)
+
+// Unfortunate: should not escape.
+func convert1(x int) uint {
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return uint(v.Convert(uintTyp).Uint())
+}
+
+// Unfortunate: should only escape content to result.
+func convert2(x []byte) string { // ERROR "leaking param: x$"
+	v := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	return v.Convert(stringTyp).String()
+}
+
+// Unfortunate: v doesn't need to leak, x (the interface storage) doesn't need to escape.
+func set1(v reflect.Value, x int) { // ERROR "leaking param: v$"
+	vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	v.Set(vx)
+}
+
+// Unfortunate: a can be stack allocated, x (the interface storage) doesn't need to escape.
+func set2(x int) int64 {
+	var a int // ERROR "moved to heap: a"
+	v := reflect.ValueOf(&a).Elem()
+	vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
+	v.Set(vx)
+	return v.Int()
+}
+
+func set3(v reflect.Value, x int) { // ERROR "v does not escape"
+	v.SetInt(int64(x))
+}
+
+func set4(x int) int {
+	var a int
+	v := reflect.ValueOf(&a).Elem() // a should not escape, no error printed
+	v.SetInt(int64(x))
+	return int(v.Int())
+}
+
+func set5(v reflect.Value, x string) { // ERROR "v does not escape" "leaking param: x$"
+	v.SetString(x)
+}
+
+func set6(v reflect.Value, x []byte) { // ERROR "v does not escape" "leaking param: x$"
+	v.SetBytes(x)
+}
+
+func set7(v reflect.Value, x unsafe.Pointer) { // ERROR "v does not escape" "leaking param: x$"
+	v.SetPointer(x)
+}
+
+func setmapindex(m map[string]string, k, e string) { // ERROR "m does not escape" "leaking param: k$" "leaking param: e$"
+	mv := reflect.ValueOf(m)
+	kv := reflect.ValueOf(k) // ERROR "k escapes to heap"
+	ev := reflect.ValueOf(e) // ERROR "e escapes to heap"
+	mv.SetMapIndex(kv, ev)
+}
+
+// Unfortunate: k doesn't need to escape.
+func mapdelete(m map[string]string, k string) { // ERROR "m does not escape" "leaking param: k$"
+	mv := reflect.ValueOf(m)
+	kv := reflect.ValueOf(k) // ERROR "k escapes to heap"
+	mv.SetMapIndex(kv, reflect.Value{})
+}
+
+// Unfortunate: v doesn't need to leak.
+func setiterkey1(v reflect.Value, it *reflect.MapIter) { // ERROR "leaking param: v$" "it does not escape"
+	v.SetIterKey(it)
+}
+
+// Unfortunate: v doesn't need to leak.
+func setiterkey2(v reflect.Value, m map[string]string) { // ERROR "leaking param: v$" "leaking param: m$"
+	it := reflect.ValueOf(m).MapRange()
+	v.SetIterKey(it)
+}
+
+// Unfortunate: v doesn't need to leak.
+func setitervalue1(v reflect.Value, it *reflect.MapIter) { // ERROR "leaking param: v$" "it does not escape"
+	v.SetIterValue(it)
+}
+
+// Unfortunate: v doesn't need to leak.
+func setitervalue2(v reflect.Value, m map[string]string) { // ERROR "leaking param: v$" "leaking param: m$"
+	it := reflect.ValueOf(m).MapRange()
+	v.SetIterValue(it)
+}
+
+// Unfortunate: s doesn't need escape, only leak to result.
+// And x (interface storage) doesn't need to escape.
+func append1(s []int, x int) []int { // ERROR "leaking param: s$"
+	sv := reflect.ValueOf(s)     // ERROR "s escapes to heap"
+	xv := reflect.ValueOf(x)     // ERROR "x escapes to heap"
+	rv := reflect.Append(sv, xv) // ERROR "... argument does not escape"
+	return rv.Interface().([]int)
+}
+
+// Unfortunate: s doesn't need escape, only leak to result.
+func append2(s, x []int) []int { // ERROR "leaking param: s$" "x does not escape"
+	sv := reflect.ValueOf(s) // ERROR "s escapes to heap"
+	xv := reflect.ValueOf(x) // ERROR "x does not escape"
+	rv := reflect.AppendSlice(sv, xv)
+	return rv.Interface().([]int)
+}