diff options
Diffstat (limited to 'test/stackobj.go')
-rw-r--r-- | test/stackobj.go | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/test/stackobj.go b/test/stackobj.go new file mode 100644 index 0000000..b6af4bd --- /dev/null +++ b/test/stackobj.go @@ -0,0 +1,57 @@ +// run + +// Copyright 2018 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. + +package main + +import ( + "fmt" + "runtime" +) + +type HeapObj [8]int64 + +type StkObj struct { + h *HeapObj +} + +var n int +var c int = -1 + +func gc() { + // encourage heap object to be collected, and have its finalizer run. + runtime.GC() + runtime.GC() + runtime.GC() + n++ +} + +func main() { + f() + gc() // prior to stack objects, heap object is not collected until here + if c < 0 { + panic("heap object never collected") + } + if c != 1 { + panic(fmt.Sprintf("expected collection at phase 1, got phase %d", c)) + } +} + +func f() { + var s StkObj + s.h = new(HeapObj) + runtime.SetFinalizer(s.h, func(h *HeapObj) { + // Remember at what phase the heap object was collected. + c = n + }) + g(&s) + gc() +} + +func g(s *StkObj) { + gc() // heap object is still live here + runtime.KeepAlive(s) + gc() // heap object should be collected here +} |