[llvm-dev] DebugInfo work contribution and update.

Wed Oct 9 11:59:15 PDT 2019

Welcome Sourabh,

There are many bits of DWARF-5 that haven’t been implemented.  I know there is currently no big push within Sony to “fill in the corners” for v5, as we have been more focused on quality of debug info for optimized code (not losing information or reporting incorrect information) and the Dexter tool.  There is no shortage of ways in which debug info for optimized code could be better; in general we are trying to post bug reports for anything we find that we’re not working on right away.

I think you are doing the right thing as far as coordinating with other people: Watch the llvm-commits and cfe-commits lists to notice when people are posting patches; post your own patches; and ask on the dev lists.  If you decide to work on something that was reported as a bug, post a note there or assign the bug to yourself.

I looked up the two PRs you cited; PR43622 is likely a simple oversight that should be easy to fix.  PR43263 doesn’t appear to be related to debug info, was that a typo?
--paulr

From: Sourabh Singh Tomar <sourav0311 at gmail.com>
Sent: Wednesday, October 09, 2019 2:38 PM
To: David Blaikie <dblaikie at gmail.com>
Cc: Adrian Prantl <aprantl at apple.com>; Robinson, Paul <paul.robinson at sony.com>; Eric Christopher <echristo at gmail.com>; Jonas Devlieghere <jdevlieghere at apple.com>; Ali Tamur <tamur at google.com>; Pavel Labath <pavel at labath.sk>; Pavel Labath <labath at google.com>; llvm-dev at lists.llvm.org; Clang Dev <cfe-dev at lists.llvm.org>; George, Jini Susan <jinisusan.george at amd.com>; sourabhsingh.tomar at amd.com
Subject: Re: [llvm-dev] DebugInfo work contribution and update.

Thanks, David for updating us.

Regarding, mail address, can use anyone{@gmail or @amd}. but sourav0311 at gmail.com<mailto:sourav0311 at gmail.com> works best for me for mailing lists related stuff.

Regarding, GDB side of DWARFv5 side of things, we've testing GDB-8.3 WRT DWARFv5 clang and gcc binaries to get better idea of debuggability of clang generated binaries with GDB.
Primary motivation being GDB better handling of gcc generated binaries, compared to clang.

We've been also tracking Ali's patches in gdb mailing list. Jini can update you better on, this one. Will ask her share update on this one.

Thanks,
Sourabh

On Wed, Oct 9, 2019 at 10:59 PM David Blaikie <dblaikie at gmail.com<mailto:dblaikie at gmail.com>> wrote:
+some other debugger people (Pavel - wasn't sure which email address you prefer, feel free to let me know (privately or publicly) for future reference)

I work at Google & we're certainly interested in DWARFv5 compliance - I'm currently working on improving debug_loclist emission to share more address pool entries ( https://reviews.llvm.org/D68620 ) which includes some improvements to llvm-dwarfdump to go with that. (Pavel's working on further improvements https://reviews.llvm.org/D68271 )

I haven't looked at/started on the loclist issue (PR43622) - so if you want to look at that, that's fine by me.

Are you also interested in the debugger side of things? GDB's DWARFv5 support is pretty incomplete & Ali's already looking at some of that, and I might get to the debug_loclist improvements necessary - but if someone else wants to do that before me, I won't complain.

Not sure of any other major holes in LLVM's DWARFv5 support, but they might be out there, for sure.

On Wed, Oct 9, 2019 at 9:37 AM Sourabh Singh Tomar via llvm-dev <llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote:
Hi llvm-dev, cfe-dev,

It's been a while since our team is investigating DebugInfo in LLVM, we're looking forward to contribute and enhance in LLVM DebugInfo.

We,'ve been investigating mostly on DWARF-5 aspects -- couple of them to mention--
1. Language aspects
2. Location mostly optimized out ones
3. DebugInfo conformance to DWARF-5

To avoid getting conflicted with some body else's work and avoiding redundancy. We would like to know the over-all state of current community developments happening WRT DWARF-5.

As of now, we're working on --
PR 43263, 43622 -- reported today {Just Now}

we'll be up-streaming patches for these.

Please let us know your thoughts, and anything else that's relevant that we need to aware of before picking up.

Thanks in anticipation!
Sourabh Singh Tomar

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