golang/go

cmd/compile: add epilogue_begin to DWARF line info

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#69,329 opened on Sep 6, 2024

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FeatureRequestNeedsInvestigationcompiler/runtimehelp wanted

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Description

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.

Contributor guide

Research direction
Investigate how the Go compiler emits prologue end DWARF markers and implement a similar mechanism for epilogue begin at function return points. Focus on the cmd/compile/internal/ssa and cmd/internal/obj packages.
Tech stack
go
Domain
backend
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
Go
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25