mirror of
https://github.com/golang/go
synced 2024-11-11 23:20:24 -07:00
68aaf2ccda
The GC program describing a data structure sometimes trusts the pointer base type and other times does not (if not, the garbage collector must fall back on per-allocation type information stored in the heap). Make the scanning of a pointer in an interface do the same. This fixes a crash in a particular use of reflect.SliceHeader. Fixes #8004. LGTM=khr R=golang-codereviews, khr CC=0xe2.0x9a.0x9b, golang-codereviews, iant, r https://golang.org/cl/100470045
60 lines
1.1 KiB
Go
60 lines
1.1 KiB
Go
// run
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// Copyright 2014 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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package main
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import (
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"reflect"
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"runtime"
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"unsafe"
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)
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func main() {
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test1()
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test2()
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}
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func test1() {
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var all []interface{}
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for i := 0; i < 100; i++ {
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p := new([]int)
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*p = append(*p, 1, 2, 3, 4)
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h := (*reflect.SliceHeader)(unsafe.Pointer(p))
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all = append(all, h, p)
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}
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runtime.GC()
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for i := 0; i < 100; i++ {
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p := *all[2*i+1].(*[]int)
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if p[0] != 1 || p[1] != 2 || p[2] != 3 || p[3] != 4 {
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println("BUG test1: bad slice at index", i, p[0], p[1], p[2], p[3])
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return
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}
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}
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}
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type T struct {
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H *reflect.SliceHeader
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P *[]int
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}
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func test2() {
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var all []T
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for i := 0; i < 100; i++ {
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p := new([]int)
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*p = append(*p, 1, 2, 3, 4)
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h := (*reflect.SliceHeader)(unsafe.Pointer(p))
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all = append(all, T{H: h}, T{P: p})
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}
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runtime.GC()
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for i := 0; i < 100; i++ {
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p := *all[2*i+1].P
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if p[0] != 1 || p[1] != 2 || p[2] != 3 || p[3] != 4 {
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println("BUG test2: bad slice at index", i, p[0], p[1], p[2], p[3])
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return
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}
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}
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}
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