llvm dev - Aug 2021 - Resolving a dependency circuit in cmake

Hi all,

Some background: our team has added Object to the LINK_COMPONENTS of  the
ProfileData library as part of work to support code coverage on baremetal
emebdded devices.
Specifically, there is a new type of InstrProfReader that opens an executable
and extracts unallocated sections as metadata, rather than relying on a
heavyweight runtime call and metadata sections living in restricted target
memory.

Recently, commit ee7d20e8 (https://reviews.llvm.org/D106861) added a dependency
on the ProfileData library to the MC library.

The combination of these changes causes a dependency circuit that results in
link-time failures:

  *   MC depends on ProfileData
  *   ProfileData depends on Object
  *   Object depends on MC

Is there any good way to resolve such dependency circuits in the build system
save for an invasive restructuring?

I'll note that in the review above, MCPseudoProbe only relies upon the
static member function FunctionSamples::getCanonicalFnName, which itself relies
on a number of static data members of FunctionSamples.

Regards,
J.B. Nagurne
Code Generation
Texas Instruments
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20210809/aaf1bba8/attachment.html>
-------------- next part --------------
An embedded message was scrubbed...
From: Cody Addison via llvm-dev <llvm-dev at lists.llvm.org>
Subject: [EXTERNAL] [llvm-dev] Code coverage for baremetal   microcontrollers
Date: Thu, 11 Oct 2018 01:41:38 +0000
Size: 8329
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20210809/aaf1bba8/attachment.mht>

+hoy at fb.com <hoy at fb.com> to bring them into the thread

That kind of static function could probably be brought out into a different
library, but I think for this some sort of agreement on the dependency
chains would be really helpful with what each library is bringing to the
table here. It might make more sense for the MC work that's been going on
here to be happening in ProfileData with that depending on Object and MC to
get work done.

Thanks!

-eric

On Mon, Aug 9, 2021 at 2:42 PM Nagurne, James via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi all,
>
>
>
> Some background: our team has added Object to the LINK_COMPONENTS of  the
> ProfileData library as part of work to support code coverage on baremetal
> emebdded devices.
>
> Specifically, there is a new type of InstrProfReader that opens an
> executable and extracts unallocated sections as metadata, rather than
> relying on a heavyweight runtime call and metadata sections living in
> restricted target memory.
>
>
>
> Recently, commit ee7d20e8 (https://reviews.llvm.org/D106861) added a
> dependency on the ProfileData library to the MC library.
>
>
>
> The combination of these changes causes a dependency circuit that results
> in link-time failures:
>
>    - MC depends on ProfileData
>    - ProfileData depends on Object
>    - Object depends on MC
>
>
>
> Is there any good way to resolve such dependency circuits in the build
> system save for an invasive restructuring?
>
>
>
> I’ll note that in the review above, MCPseudoProbe only relies upon the
> static member function FunctionSamples::getCanonicalFnName, which itself
> relies on a number of static data members of FunctionSamples.
>
>
>
> Regards,
>
> J.B. Nagurne
>
> Code Generation
>
> Texas Instruments
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20210809/f4a97de9/attachment.html>