1 // run 2 3 // Copyright 2014 The Go Authors. All rights reserved. 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file. 6 7 package main 8 9 import ( 10 "reflect" 11 "runtime" 12 "unsafe" 13 ) 14 15 func main() { 16 test1() 17 test2() 18 } 19 20 func test1() { 21 var all []interface{} 22 for i := 0; i < 100; i++ { 23 p := new([]int) 24 *p = append(*p, 1, 2, 3, 4) 25 h := (*reflect.SliceHeader)(unsafe.Pointer(p)) 26 all = append(all, h, p) 27 } 28 runtime.GC() 29 for i := 0; i < 100; i++ { 30 p := *all[2*i+1].(*[]int) 31 if p[0] != 1 || p[1] != 2 || p[2] != 3 || p[3] != 4 { 32 println("BUG test1: bad slice at index", i, p[0], p[1], p[2], p[3]) 33 return 34 } 35 } 36 } 37 38 type T struct { 39 H *reflect.SliceHeader 40 P *[]int 41 } 42 43 func test2() { 44 var all []T 45 for i := 0; i < 100; i++ { 46 p := new([]int) 47 *p = append(*p, 1, 2, 3, 4) 48 h := (*reflect.SliceHeader)(unsafe.Pointer(p)) 49 all = append(all, T{H: h}, T{P: p}) 50 } 51 runtime.GC() 52 for i := 0; i < 100; i++ { 53 p := *all[2*i+1].P 54 if p[0] != 1 || p[1] != 2 || p[2] != 3 || p[3] != 4 { 55 println("BUG test2: bad slice at index", i, p[0], p[1], p[2], p[3]) 56 return 57 } 58 } 59 } 60
