Thanks. I'll give that doc a read. Just to make sure, I noticed that the doc is dated 2015, but the escape analysis implementation seemed to change just recently from that implemented in esc.go to a new one in escape.go. Dose the doc still apply to the new implementation?
On Thu, Mar 5, 2020 at 4:20 AM tokers <zchao1...@gmail.com> wrote: > This is a known deficiency of Go's escape analysis, which is recorded in > this doc: > https://docs.google.com/document/d/1CxgUBPlx9iJzkz9JWkb6tIpTe5q32QDmz8l0BouG0Cw/view# > > On Thursday, March 5, 2020 at 5:58:37 AM UTC+8, burns...@gmail.com wrote: >> >> Hi All, >> >> I am trying to debug why a byte slice is escaping in my program. I have a >> small reproducible example here: >> >> % cat escape.go >> package main >> >> func main() { >> x := make([]byte, 5) >> y := new([]byte) >> *y = x >> nothing((*y)[3]) >> } >> >> func nothing(b byte) {} >> % go tool compile -m -m -l escape.go >> escape.go:4:11: make([]byte, 5) escapes to heap: >> escape.go:4:11: flow: x = &{storage for make([]byte, 5)}: >> escape.go:4:11: from make([]byte, 5) (spill) at escape.go:4:11 >> escape.go:4:11: from x := make([]byte, 5) (assign) at escape.go:4:4 >> escape.go:4:11: flow: {heap} = x: >> escape.go:4:11: from *y = x (assign) at escape.go:6:5 >> escape.go:4:11: make([]byte, 5) escapes to heap >> escape.go:5:10: new([]byte) does not escape >> >> It seems to me like neither x nor it's backing array should escape, but >> I'm having trouble figuring out why it's flagged as escaping from the debug >> output. >> >> % go version >> go version go1.14 darwin/amd64 >> >> >> Any help would be appreciated. >> >> Ethan >> >> -- > You received this message because you are subscribed to a topic in the > Google Groups "golang-nuts" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/golang-nuts/2s0_gQjR7yE/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > golang-nuts+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/golang-nuts/646ff0ef-2feb-409b-9ac4-8c667b40b392%40googlegroups.com > <https://groups.google.com/d/msgid/golang-nuts/646ff0ef-2feb-409b-9ac4-8c667b40b392%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/CAGE%3DEi2Bdzydu%2BzGHA0-xmMd0NTrBePBcTFAAvm1A-1RLiaa9Q%40mail.gmail.com.
