search

golang / go

The Go programming language
https://go.dev
BSD 3-Clause "New" or "Revised" License
124.3k stars 17.7k forks source link

cmd/compile: add epilogue_begin to DWARF line info #69329

Open ajwerner opened 2 months ago

ajwerner commented 2 months ago

Go does not currently (as of go1.23) emit epilogue_begin markers around where functions return. It does emit prologue_end.

The motivation here is that go is not friendly to things like ebpf return probes (uretprobe) because they inject a call frame into the stack (see https://github.com/iovisor/bcc/issues/1320).

What folks do instead is simulate these return probes by finding all of the returns sites by parsing the text of the program (see https://github.com/iovisor/bcc/issues/1320#issuecomment-982020012). A more general approach that doesn't require access to the binary would be to store the relevant information in the line info.

timothy-king commented 2 months ago

CC @golang/compiler

AlexanderYastrebov commented 2 months ago

go is not friendly to things like ebpf return probes (uretprobe)

See #22008

ajwerner commented 2 months ago

Thanks for the cross-reference! To clarify, this issue would help not in that it would make uretprobes work, but that it makes them easier to simulate with uprobes because it'll make it easier to find the return points using debug information rather than having to parse the program text.