1 // run 2 3 // Copyright 2009 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 // Test stack splitting code. 8 // Try to tickle stack splitting bugs by doing 9 // go, defer, and closure calls at different stack depths. 10 11 package main 12 13 type T [20]int 14 15 func g(c chan int, t T) { 16 s := 0 17 for i := 0; i < len(t); i++ { 18 s += t[i] 19 } 20 c <- s 21 } 22 23 func d(t T) { 24 s := 0 25 for i := 0; i < len(t); i++ { 26 s += t[i] 27 } 28 if s != len(t) { 29 println("bad defer", s) 30 panic("fail") 31 } 32 } 33 34 func f0() { 35 // likely to make a new stack for f0, 36 // because the call to f1 puts 3000 bytes 37 // in our frame. 38 f1() 39 } 40 41 func f1() [3000]byte { 42 // likely to make a new stack for f1, 43 // because 3000 bytes were used by f0 44 // and we need 3000 more for the call 45 // to f2. if the call to morestack in f1 46 // does not pass the frame size, the new 47 // stack (default size 5k) will not be big 48 // enough for the frame, and the morestack 49 // check in f2 will die, if we get that far 50 // without faulting. 51 f2() 52 return [3000]byte{} 53 } 54 55 func f2() [3000]byte { 56 // just take up space 57 return [3000]byte{} 58 } 59 60 var c = make(chan int) 61 var t T 62 var b = []byte{1, 2, 3, 4, 5, 6, 7, 8, 9, 10} 63 64 func recur(n int) { 65 ss := string(b) 66 if len(ss) != len(b) { 67 panic("bad []byte -> string") 68 } 69 go g(c, t) 70 f0() 71 s := <-c 72 if s != len(t) { 73 println("bad go", s) 74 panic("fail") 75 } 76 f := func(t T) int { 77 s := 0 78 for i := 0; i < len(t); i++ { 79 s += t[i] 80 } 81 s += n 82 return s 83 } 84 s = f(t) 85 if s != len(t)+n { 86 println("bad func", s, "at level", n) 87 panic("fail") 88 } 89 if n > 0 { 90 recur(n - 1) 91 } 92 defer d(t) 93 } 94 95 func main() { 96 for i := 0; i < len(t); i++ { 97 t[i] = 1 98 } 99 recur(8000) 100 } 101
