mirror of
https://github.com/golang/go
synced 2024-11-05 12:06:15 -07:00
42fd1306ce
We're using sort.SliceStable, so no need to keep track of indexes as well. Use a more robust test for whether a node is a call. Add a test that we're actually reordering comparisons. This test fails without the alg.go changes in this CL because eqstring uses OCALLFUNC instead of OCALL for its data comparisons. Update #8606 Change-Id: Ieeec33434c72e3aa328deb11cc415cfda05632e2 Reviewed-on: https://go-review.googlesource.com/c/go/+/237921 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Matthew Dempsky <mdempsky@google.com>
64 lines
1.6 KiB
Go
64 lines
1.6 KiB
Go
// run
|
|
|
|
// Copyright 2020 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.
|
|
|
|
// This is an optimization check. We want to make sure that we compare
|
|
// string lengths, and other scalar fields, before checking string
|
|
// contents. There's no way to verify this in the language, and
|
|
// codegen tests in test/codegen can't really detect ordering
|
|
// optimizations like this. Instead, we generate invalid strings with
|
|
// bad backing store pointers but nonzero length, so we can check that
|
|
// the backing store never gets compared.
|
|
//
|
|
// We use two different bad strings so that pointer comparisons of
|
|
// backing store pointers fail.
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
"unsafe"
|
|
)
|
|
|
|
func bad1() string {
|
|
s := "foo"
|
|
(*reflect.StringHeader)(unsafe.Pointer(&s)).Data = 1 // write bad value to data ptr
|
|
return s
|
|
}
|
|
func bad2() string {
|
|
s := "foo"
|
|
(*reflect.StringHeader)(unsafe.Pointer(&s)).Data = 2 // write bad value to data ptr
|
|
return s
|
|
}
|
|
|
|
type SI struct {
|
|
s string
|
|
i int
|
|
}
|
|
|
|
type SS struct {
|
|
s string
|
|
t string
|
|
}
|
|
|
|
func main() {
|
|
for _, test := range []struct {
|
|
a, b interface{}
|
|
}{
|
|
{SI{s: bad1(), i: 1}, SI{s: bad2(), i: 2}},
|
|
{SS{s: bad1(), t: "a"}, SS{s: bad2(), t: "aa"}},
|
|
{SS{s: "a", t: bad1()}, SS{s: "b", t: bad2()}},
|
|
// This one would panic because the length of both strings match, and we check
|
|
// the body of the bad strings before the body of the good strings.
|
|
//{SS{s: bad1(), t: "a"}, SS{s: bad2(), t: "b"}},
|
|
} {
|
|
if test.a == test.b {
|
|
panic(fmt.Sprintf("values %#v and %#v should not be equal", test.a, test.b))
|
|
}
|
|
}
|
|
|
|
}
|