Account for inlined frames from blazesym

[bobrik]

Testing with:

symbolizer, err := blazesym.NewSymbolizer()
if err != nil {
    panic(err)
}

syms, err := symbolizer.Symbolize(3061398, []uint64{0x5639d417c164})
if err != nil {
    panic(err)
}

for _, sym := range syms {
    fmt.Printf("%#v\n", sym)
}

Here's the output:

blazesym.Symbol{Name:"outie", File:"derp.c", Dir:"/home/ivan/.", Line:16, Column:10, Offset:13}
blazesym.Symbol{Name:"middle", File:"derp.c", Dir:"/home/ivan/.", Line:12, Column:10, Offset:0}

It matches blazecli:

$ sudo ../target/debug/blazecli symbolize process --pid 3061398 0x5639d417c164
0x005639d417c164: outie @ 0x1157+0xd /home/ivan/./derp.c:16:10
                  middle @ /home/ivan/./derp.c:12:10 [inlined]

• Added tests, if you've added code that should be tested
• Updated the documentation, if you've changed APIs
• Ensured the test suite passes
• Made sure your code lints
• Completed the Contributor License Agreement ("CLA")

[bobrik]

I find myself needing ELF based symbolication and I think this needs to be a standalone Go library. I can make one, but perhaps facebook people should own it instead, given that they own blazesym itself?

@d-e-s-o, let me know what you think.

[d-e-s-o]

@bobrik I don't think we are going to maintain a second symbolization library just for the sake of having a pure Go implementation, assuming that is what you are asking. Can you help me better understand what the problem you are facing is?

[bobrik]

I'm not suggesting a pure Go library. My suggestion is a Go wrapper around C bindings, same as we have here, but in a separate project just for blazesym (as opposed to a part of facebook/dns).

The problem I'm facing is that I would like to use blazesym from Go. The only Go library is a part of facebook/dns here:

• https://pkg.go.dev/search?q=blazesym

It is weird to import facebook/dns for symbolication and it's quite limited in what it actually provides at the moment.

[meta-codesync]

@virtyaluk has imported this pull request. If you are a Meta employee, you can view this in D89894658.

[d-e-s-o]

I see; different "standalone" then. Yeah, that would make sense. I think we can provide "official" bindings that reside in the blazesym repository itself (where we do have test binaries, testing infra, and it's easiest to keep everything in-sync), but we don't really have Go expertise on the team. So I think it would be best if at least the initial version would be contributed by the community. Given that it sounds as if you considered writing such a library, perhaps that's something you'd be interested in upstreaming?

I think the main hurdle/questionmark from my perspective would be how to make the Rust usage transparent to users, so I suspect that will need a bit more discussion. I am being told that perhaps pre-built binaries may be the most idiomatic way to go, but I don't have the necessary Go-overview here.

[bobrik]

I made libbpf/blazesym#1402. Lets move the discussion there.

[meta-codesync]

@virtyaluk merged this pull request in e43fa1f.