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author | Keith Randall <keithr@alum.mit.edu> | 2018-09-07 14:55:09 -0700 |
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committer | Keith Randall <khr@golang.org> | 2018-10-03 19:54:16 +0000 |
commit | 9a8372f8bd5a39d2476bfa9247407b51f9193b9e (patch) | |
tree | c8383f43af15466e5320044f5910c55073c41592 /test/stackobj.go | |
parent | cbafcc55e80d5b444e659a892b739c04a27980d3 (diff) | |
download | go-9a8372f8bd5a39d2476bfa9247407b51f9193b9e.tar.gz go-9a8372f8bd5a39d2476bfa9247407b51f9193b9e.zip |
cmd/compile,runtime: remove ambiguously live logic
The previous CL introduced stack objects. This CL removes the old
ambiguously live liveness analysis. After this CL we're relying
on stack objects exclusively.
Update a bunch of liveness tests to reflect the new world.
Fixes #22350
Change-Id: I739b26e015882231011ce6bc1a7f426049e59f31
Reviewed-on: https://go-review.googlesource.com/c/134156
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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 0000000000..b6af4bd8f3 --- /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 +} |