codekingpro/portable-devtools

1// run2 3// Copyright 2018 The Go Authors. All rights reserved.4// Use of this source code is governed by a BSD-style5// license that can be found in the LICENSE file.6 7package main8 9import (10	"fmt"11	"runtime"12)13 14// linked list up the stack, to test lots of stack objects.15 16type T struct {17	// points to a heap object. Test will make sure it isn't freed.18	data *int6419	// next pointer for a linked list of stack objects20	next *T21	// duplicate of next, to stress test the pointer buffers22	// used during stack tracing.23	next2 *T24}25 26func main() {27	makelist(nil, 10000)28}29 30func makelist(x *T, n int64) {31	if n%2 != 0 {32		panic("must be multiple of 2")33	}34	if n == 0 {35		runtime.GC()36		i := int64(1)37		for ; x != nil; x, i = x.next, i+1 {38			// Make sure x.data hasn't been collected.39			if got := *x.data; got != i {40				panic(fmt.Sprintf("bad data want %d, got %d", i, got))41			}42		}43		return44	}45	// Put 2 objects in each frame, to test intra-frame pointers.46	// Use both orderings to ensure the linked list isn't always in address order.47	var a, b T48	if n%3 == 0 {49		a.data = newInt(n)50		a.next = x51		a.next2 = x52		b.data = newInt(n - 1)53		b.next = &a54		b.next2 = &a55		x = &b56	} else {57		b.data = newInt(n)58		b.next = x59		b.next2 = x60		a.data = newInt(n - 1)61		a.next = &b62		a.next2 = &b63		x = &a64	}65 66	makelist(x, n-2)67}68 69// big enough and pointer-y enough to not be tinyalloc'd70type NotTiny struct {71	n int6472	p *byte73}74 75// newInt allocates n on the heap and returns a pointer to it.76func newInt(n int64) *int64 {77	h := &NotTiny{n: n}78	p := &h.n79	escape = p80	return p81}82 83var escape *int6484