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994eca4883
With CL 408826 reflect.Value does not always escape. We need to make sure Value operations does (or does not) escape the Value correctly. This CL adds a test. There are still a few unfortunate cases, where some Value operations escape more than necessary (comparing to a non-reflect version of the code), but hard to fix. These are mostly that a Value would escape conditionally (mostly on the type of the Value), but currently we don't have a good way to express that. Change-Id: I9fdfc7584670aa09c5a01f6b2803f2043aaddb65 Reviewed-on: https://go-review.googlesource.com/c/go/+/441938 Run-TryBot: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
463 lines
13 KiB
Go
463 lines
13 KiB
Go
// errorcheck -0 -m -l
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test escape analysis for reflect Value operations.
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package escape
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import (
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"reflect"
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"unsafe"
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)
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var sink interface{}
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func typ(x int) any {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Type()
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}
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func kind(x int) reflect.Kind {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Kind()
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}
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func int1(x int) int {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return int(v.Int())
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}
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func ptr(x *int) *int { // ERROR "leaking param: x to result ~r0 level=0"
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v := reflect.ValueOf(x)
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return (*int)(v.UnsafePointer())
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}
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func bytes1(x []byte) byte { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Bytes()[0]
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}
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// Unfortunate: should only escape content. x (the interface storage) should not escape.
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func bytes2(x []byte) []byte { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Bytes()
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}
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func string1(x string) string { // ERROR "leaking param: x to result ~r0 level=0"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.String()
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}
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func string2(x int) string {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.String()
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}
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// Unfortunate: should only escape to result.
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func interface1(x any) any { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x)
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return v.Interface()
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}
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func interface2(x int) any {
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Interface()
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}
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// Unfortunate: should not escape.
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func interface3(x int) int {
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Interface().(int)
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}
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// Unfortunate: should only escape to result.
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func interface4(x *int) any { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x)
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return v.Interface()
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}
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func addr(x *int) reflect.Value { // ERROR "leaking param: x to result ~r0 level=0"
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v := reflect.ValueOf(x).Elem()
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return v.Addr()
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}
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// functions returning pointer as uintptr have to escape.
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func uintptr1(x *int) uintptr { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x)
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return v.Pointer()
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}
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func unsafeaddr(x *int) uintptr { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x).Elem()
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return v.UnsafeAddr()
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}
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func ifacedata(x any) [2]uintptr { // ERROR "moved to heap: x"
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v := reflect.ValueOf(&x).Elem()
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return v.InterfaceData()
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}
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func can(x int) bool {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.CanAddr() || v.CanInt() || v.CanSet() || v.CanInterface()
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}
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func is(x int) bool {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.IsValid() || v.IsNil() || v.IsZero()
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}
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func is2(x [2]int) bool {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.IsValid() || v.IsNil() || v.IsZero()
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}
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func is3(x struct { a, b int }) bool {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.IsValid() || v.IsNil() || v.IsZero()
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}
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func overflow(x int) bool {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.OverflowInt(1 << 62)
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}
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func len1(x []int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Len()
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}
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func len2(x [3]int) int {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Len()
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}
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func len3(x string) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Len()
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}
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func len4(x map[int]int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x)
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return v.Len()
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}
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func len5(x chan int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x)
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return v.Len()
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}
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func cap1(x []int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Cap()
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}
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func cap2(x [3]int) int {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Cap()
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}
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func cap3(x chan int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x)
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return v.Cap()
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}
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func setlen(x *[]int, n int) { // ERROR "x does not escape"
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v := reflect.ValueOf(x).Elem()
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v.SetLen(n)
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}
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func setcap(x *[]int, n int) { // ERROR "x does not escape"
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v := reflect.ValueOf(x).Elem()
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v.SetCap(n)
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}
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// Unfortunate: x doesn't need to escape to heap, just to result.
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func slice1(x []byte) []byte { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Slice(1, 2).Bytes()
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}
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// Unfortunate: x doesn't need to escape to heap, just to result.
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func slice2(x string) string { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Slice(1, 2).String()
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}
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func slice3(x [10]byte) []byte {
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Slice(1, 2).Bytes()
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}
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func elem1(x *int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x)
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return int(v.Elem().Int())
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}
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func elem2(x *string) string { // ERROR "leaking param: x to result ~r0 level=1"
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v := reflect.ValueOf(x)
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return string(v.Elem().String())
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}
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type S struct {
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A int
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B *int
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C string
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}
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func (S) M() {}
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func field1(x S) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return int(v.Field(0).Int())
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}
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func field2(x S) string { // ERROR "leaking param: x to result ~r0 level=0"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Field(2).String()
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}
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func numfield(x S) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.NumField()
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}
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func index1(x []int) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return int(v.Index(0).Int())
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}
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// Unfortunate: should only leak content (level=1)
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func index2(x []string) string { // ERROR "leaking param: x to result ~r0 level=0"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Index(0).String()
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}
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func index3(x [3]int) int {
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return int(v.Index(0).Int())
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}
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func index4(x [3]string) string { // ERROR "leaking param: x to result ~r0 level=0"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.Index(0).String()
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}
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func index5(x string) byte { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return byte(v.Index(0).Uint())
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}
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// Unfortunate: x (the interface storage) doesn't need to escape as the function takes a scalar arg.
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func call1(f func(int), x int) { // ERROR "leaking param: f$"
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fv := reflect.ValueOf(f)
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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fv.Call([]reflect.Value{v}) // ERROR "\[\]reflect\.Value{\.\.\.} does not escape"
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}
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func call2(f func(*int), x *int) { // ERROR "leaking param: f$" "leaking param: x$"
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fv := reflect.ValueOf(f)
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v := reflect.ValueOf(x)
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fv.Call([]reflect.Value{v}) // ERROR "\[\]reflect.Value{\.\.\.} does not escape"
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}
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func method(x S) reflect.Value { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Method(0)
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}
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func nummethod(x S) int { // ERROR "x does not escape"
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v := reflect.ValueOf(x) // ERROR "x does not escape"
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return v.NumMethod()
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}
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// Unfortunate: k doesn't need to escape.
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func mapindex(m map[string]string, k string) string { // ERROR "m does not escape" "leaking param: k$"
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mv := reflect.ValueOf(m)
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kv := reflect.ValueOf(k) // ERROR "k escapes to heap"
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return mv.MapIndex(kv).String()
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}
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func mapkeys(m map[string]string) []reflect.Value { // ERROR "m does not escape"
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mv := reflect.ValueOf(m)
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return mv.MapKeys()
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}
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func mapiter1(m map[string]string) *reflect.MapIter { // ERROR "leaking param: m$"
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mv := reflect.ValueOf(m)
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return mv.MapRange()
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}
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func mapiter2(m map[string]string) string { // ERROR "leaking param: m$"
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mv := reflect.ValueOf(m)
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it := mv.MapRange()
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if it.Next() {
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return it.Key().String()
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}
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return ""
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}
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func mapiter3(m map[string]string, it *reflect.MapIter) { // ERROR "leaking param: m$" "it does not escape"
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mv := reflect.ValueOf(m)
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it.Reset(mv)
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}
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func recv1(ch chan string) string { // ERROR "ch does not escape"
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v := reflect.ValueOf(ch)
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r, _ := v.Recv()
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return r.String()
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}
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func recv2(ch chan string) string { // ERROR "ch does not escape"
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v := reflect.ValueOf(ch)
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r, _ := v.TryRecv()
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return r.String()
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}
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// Unfortunate: x (the interface storage) doesn't need to escape.
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func send1(ch chan string, x string) { // ERROR "ch does not escape" "leaking param: x$"
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vc := reflect.ValueOf(ch)
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vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
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vc.Send(vx)
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}
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// Unfortunate: x (the interface storage) doesn't need to escape.
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func send2(ch chan string, x string) bool { // ERROR "ch does not escape" "leaking param: x$"
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vc := reflect.ValueOf(ch)
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vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return vc.TrySend(vx)
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}
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func close1(ch chan string) { // ERROR "ch does not escape"
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v := reflect.ValueOf(ch)
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v.Close()
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}
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func select1(ch chan string) string { // ERROR "leaking param: ch$"
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v := reflect.ValueOf(ch)
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cas := reflect.SelectCase{Dir: reflect.SelectRecv, Chan: v}
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_, r, _ := reflect.Select([]reflect.SelectCase{cas}) // ERROR "\[\]reflect.SelectCase{...} does not escape"
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return r.String()
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}
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// Unfortunate: x (the interface storage) doesn't need to escape.
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func select2(ch chan string, x string) { // ERROR "leaking param: ch$" "leaking param: x$"
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vc := reflect.ValueOf(ch)
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vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
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cas := reflect.SelectCase{Dir: reflect.SelectSend, Chan: vc, Send: vx}
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reflect.Select([]reflect.SelectCase{cas}) // ERROR "\[\]reflect.SelectCase{...} does not escape"
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}
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var (
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intTyp = reflect.TypeOf(int(0)) // ERROR "int\(0\) does not escape"
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uintTyp = reflect.TypeOf(uint(0)) // ERROR "uint\(0\) does not escape"
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stringTyp = reflect.TypeOf(string("")) // ERROR "string\(.*\) does not escape"
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bytesTyp = reflect.TypeOf([]byte{}) // ERROR "\[\]byte{} does not escape"
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)
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// Unfortunate: should not escape.
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func convert1(x int) uint {
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return uint(v.Convert(uintTyp).Uint())
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}
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// Unfortunate: should only escape content to result.
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func convert2(x []byte) string { // ERROR "leaking param: x$"
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v := reflect.ValueOf(x) // ERROR "x escapes to heap"
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return v.Convert(stringTyp).String()
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}
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// Unfortunate: v doesn't need to leak, x (the interface storage) doesn't need to escape.
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func set1(v reflect.Value, x int) { // ERROR "leaking param: v$"
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vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
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v.Set(vx)
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}
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// Unfortunate: a can be stack allocated, x (the interface storage) doesn't need to escape.
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func set2(x int) int64 {
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var a int // ERROR "moved to heap: a"
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v := reflect.ValueOf(&a).Elem()
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vx := reflect.ValueOf(x) // ERROR "x escapes to heap"
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v.Set(vx)
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return v.Int()
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}
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func set3(v reflect.Value, x int) { // ERROR "v does not escape"
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v.SetInt(int64(x))
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}
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func set4(x int) int {
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var a int
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v := reflect.ValueOf(&a).Elem() // a should not escape, no error printed
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v.SetInt(int64(x))
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return int(v.Int())
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}
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func set5(v reflect.Value, x string) { // ERROR "v does not escape" "leaking param: x$"
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v.SetString(x)
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}
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func set6(v reflect.Value, x []byte) { // ERROR "v does not escape" "leaking param: x$"
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v.SetBytes(x)
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}
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func set7(v reflect.Value, x unsafe.Pointer) { // ERROR "v does not escape" "leaking param: x$"
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v.SetPointer(x)
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}
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func setmapindex(m map[string]string, k, e string) { // ERROR "m does not escape" "leaking param: k$" "leaking param: e$"
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mv := reflect.ValueOf(m)
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kv := reflect.ValueOf(k) // ERROR "k escapes to heap"
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ev := reflect.ValueOf(e) // ERROR "e escapes to heap"
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mv.SetMapIndex(kv, ev)
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}
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// Unfortunate: k doesn't need to escape.
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func mapdelete(m map[string]string, k string) { // ERROR "m does not escape" "leaking param: k$"
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mv := reflect.ValueOf(m)
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kv := reflect.ValueOf(k) // ERROR "k escapes to heap"
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mv.SetMapIndex(kv, reflect.Value{})
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}
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// Unfortunate: v doesn't need to leak.
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func setiterkey1(v reflect.Value, it *reflect.MapIter) { // ERROR "leaking param: v$" "it does not escape"
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v.SetIterKey(it)
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}
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// Unfortunate: v doesn't need to leak.
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func setiterkey2(v reflect.Value, m map[string]string) { // ERROR "leaking param: v$" "leaking param: m$"
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it := reflect.ValueOf(m).MapRange()
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v.SetIterKey(it)
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}
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// Unfortunate: v doesn't need to leak.
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func setitervalue1(v reflect.Value, it *reflect.MapIter) { // ERROR "leaking param: v$" "it does not escape"
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v.SetIterValue(it)
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}
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// Unfortunate: v doesn't need to leak.
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func setitervalue2(v reflect.Value, m map[string]string) { // ERROR "leaking param: v$" "leaking param: m$"
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it := reflect.ValueOf(m).MapRange()
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v.SetIterValue(it)
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}
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// Unfortunate: s doesn't need escape, only leak to result.
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// And x (interface storage) doesn't need to escape.
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func append1(s []int, x int) []int { // ERROR "leaking param: s$"
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sv := reflect.ValueOf(s) // ERROR "s escapes to heap"
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xv := reflect.ValueOf(x) // ERROR "x escapes to heap"
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rv := reflect.Append(sv, xv) // ERROR "... argument does not escape"
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return rv.Interface().([]int)
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}
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// Unfortunate: s doesn't need escape, only leak to result.
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func append2(s, x []int) []int { // ERROR "leaking param: s$" "x does not escape"
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sv := reflect.ValueOf(s) // ERROR "s escapes to heap"
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xv := reflect.ValueOf(x) // ERROR "x does not escape"
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rv := reflect.AppendSlice(sv, xv)
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return rv.Interface().([]int)
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}
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