From ccd992355df7192993c666236047820244914598 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Tue, 16 Apr 2024 21:19:13 +0200 Subject: Adding upstream version 1.21.8. Signed-off-by: Daniel Baumann --- test/fixedbugs/issue8606b.go | 70 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) create mode 100644 test/fixedbugs/issue8606b.go (limited to 'test/fixedbugs/issue8606b.go') diff --git a/test/fixedbugs/issue8606b.go b/test/fixedbugs/issue8606b.go new file mode 100644 index 0000000..41b9a3d --- /dev/null +++ b/test/fixedbugs/issue8606b.go @@ -0,0 +1,70 @@ +// run +// +build linux darwin + +// 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" + "syscall" + "unsafe" +) + +type SI struct { + s string + i int +} + +type SS struct { + s string + t string +} + +func main() { + bad1 := "foo" + bad2 := "foo" + + p := syscall.Getpagesize() + b, err := syscall.Mmap(-1, 0, p, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANON|syscall.MAP_PRIVATE) + if err != nil { + panic(err) + } + err = syscall.Mprotect(b, syscall.PROT_NONE) + if err != nil { + panic(err) + } + // write inaccessible pointers as the data fields of bad1 and bad2. + (*reflect.StringHeader)(unsafe.Pointer(&bad1)).Data = uintptr(unsafe.Pointer(&b[0])) + (*reflect.StringHeader)(unsafe.Pointer(&bad2)).Data = uintptr(unsafe.Pointer(&b[1])) + + 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)) + } + } + +} -- cgit v1.2.3