llvm dev - Feb 2020 - How to help improve debug experience w/ optimizations enabled?

Hello,

I'd like to help improve the debug experience in LLVM/Clang when
optimizations are enabled, but I'm not sure where to start.
I've seen the umbrella bug for poor debug experiences (38768
https://bugs.llvm.org/show_bug.cgi?id=38768 ).
Is there any bug in this list that isn't being looked at (and that
doesn't require a lot of knowledge) that I could work on?

I also tried using Dexter (https://github.com/SNSystems/dexter ) to find issues,
but it's hard to find something that I can fix in a reasonable amount of
time using Dexter alone as I don't have enough LLVM experience to know where
to look at/what to look for.

In general, if I want to find bug reports about missing debug info/poor debug
experience, where should I look at?
e.g. bug trackers for clang-built projects, particular code examples, issues you
encountered but haven't reported yet, etc.

Thank you.

Kind regards,
Pierre van Houtryve
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Hello Pierre,

We have certainly tried to make bug 38768 the umbrella for all the various poor
experiences.  If other projects have poor debugging experiences when using
clang, they should be reporting them here; otherwise we won't know about
them.
You could also look at bug 37953 (https://bugs.llvm.org/show_bug.cgi?id=37953)
which is an umbrella for bugs where we seem to lose track of debug info,
although these do not necessarily lead to poor debugging experiences.  They are
generally simpler, and would be a better choice for getting started with the
LLVM project.  I'd suggest starting with one or two of these before getting
into the tougher problems under bug 38768.

Welcome to one of the nicer open-source communities around, and if you get stuck
we can usually provide some help to get you going again.
--paulr


From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Pierre
van Houtryve via llvm-dev
Sent: Monday, February 24, 2020 7:06 AM
To: llvm-dev at lists.llvm.org
Subject: [llvm-dev] How to help improve debug experience w/ optimizations
enabled?

Hello,

I'd like to help improve the debug experience in LLVM/Clang when
optimizations are enabled, but I'm not sure where to start.
I've seen the umbrella bug for poor debug experiences (38768
https://bugs.llvm.org/show_bug.cgi?id=38768 ).
Is there any bug in this list that isn't being looked at (and that
doesn't require a lot of knowledge) that I could work on?

I also tried using Dexter (https://github.com/SNSystems/dexter ) to find issues,
but it's hard to find something that I can fix in a reasonable amount of
time using Dexter alone as I don't have enough LLVM experience to know where
to look at/what to look for.

In general, if I want to find bug reports about missing debug info/poor debug
experience, where should I look at?
e.g. bug trackers for clang-built projects, particular code examples, issues you
encountered but haven't reported yet, etc.

Thank you.

Kind regards,
Pierre van Houtryve
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+ 1 to Paul’s suggestions.

I’d add that if an open bug report isn’t assigned to anyone, you can assume it’s
fair game. Feel free to assign a bug to yourself if you start working on it.

To toss another idea out there, you might try picking a small .o and working
backwards to figure out why location information in it is incorrect. This can
reveal a different set of bugs compared to e.g. running -check-debugify on IR
passes.
> On Feb 24, 2020, at 10:51 AM, Robinson, Paul via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> 
> Hello Pierre,
>  
> We have certainly tried to make bug 38768 the umbrella for all the various
poor experiences.  If other projects have poor debugging experiences when using
clang, they should be reporting them here; otherwise we won’t know about them.
> You could also look at bug 37953
(https://bugs.llvm.org/show_bug.cgi?id=37953) which is an umbrella for bugs
where we seem to lose track of debug info, although these do not necessarily
lead to poor debugging experiences.  They are generally simpler, and would be a
better choice for getting started with the LLVM project.  I’d suggest starting
with one or two of these before getting into the tougher problems under bug
38768.
>  
> Welcome to one of the nicer open-source communities around, and if you get
stuck we can usually provide some help to get you going again.
> --paulr
>  
>  
> From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of
Pierre van Houtryve via llvm-dev
> Sent: Monday, February 24, 2020 7:06 AM
> To: llvm-dev at lists.llvm.org
> Subject: [llvm-dev] How to help improve debug experience w/ optimizations
enabled?
>  
> Hello,
>  
> I'd like to help improve the debug experience in LLVM/Clang when
optimizations are enabled, but I'm not sure where to start.
> I've seen the umbrella bug for poor debug experiences (38768
https://bugs.llvm.org/show_bug.cgi?id=38768 ).
> Is there any bug in this list that isn't being looked at (and that
doesn't require a lot of knowledge) that I could work on?
> 
> I also tried using Dexter (https://github.com/SNSystems/dexter ) to find
issues, but it's hard to find something that I can fix in a reasonable
amount of time using Dexter alone as I don't have enough LLVM experience to
know where to look at/what to look for.
> 
> In general, if I want to find bug reports about missing debug info/poor
debug experience, where should I look at?
> e.g. bug trackers for clang-built projects, particular code examples,
issues you encountered but haven't reported yet, etc.
> 
> Thank you.
>  
> Kind regards,
> Pierre van Houtryve
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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