cmd/compile: fix mishandling of unsafe-uintptr arguments in go/defer

Currently, the statement:

	go g(uintptr(f()))

gets rewritten into:

	tmp := f()
	newproc(8, g, uintptr(tmp))
	runtime.KeepAlive(tmp)

which doesn't guarantee that tmp is still alive by time the g call is
scheduled to run.

This CL fixes the issue, by wrapping g call in a closure:

	go func(p unsafe.Pointer) {
		g(uintptr(p))
	}(f())

then this will be rewritten into:

	tmp := f()
	go func(p unsafe.Pointer) {
		g(uintptr(p))
		runtime.KeepAlive(p)
	}(tmp)
	runtime.KeepAlive(tmp)  // superfluous, but harmless

So the unsafe.Pointer p will be kept alive at the time g call runs.

Updates #24491

Change-Id: Ic10821251cbb1b0073daec92b82a866c6ebaf567
Reviewed-on: https://go-review.googlesource.com/c/go/+/253457
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
4 files changed
tree: 4875cdbf806e7088be9a261cf61135bda02138e9
  1. .gitattributes
  2. .github/
  3. .gitignore
  4. AUTHORS
  5. CONTRIBUTING.md
  6. CONTRIBUTORS
  7. LICENSE
  8. PATENTS
  9. README.md
  10. SECURITY.md
  11. api/
  12. doc/
  13. favicon.ico
  14. lib/
  15. misc/
  16. robots.txt
  17. src/
  18. test/
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