Re: [PATCH] Add gnu::diagnose_as attribute

[Matthias Kretz <m.kretz@gsi.de>]

On Tuesday, 4 May 2021 15:34:13 CEST David Malcolm wrote:
> On Tue, 2021-05-04 at 13:13 +0200, Matthias Kretz wrote:
> > This attribute overrides the diagnostics output string for the entity
> > it
> > appertains to. The motivation is to improve QoI for library TS
> > implementations, where diagnostics have a very bad signal-to-noise
> > ratio
> > due to the long namespaces involved.
> > [...]
> 
> Thanks for the patch, it looks very promising.

Thanks. I'm new to modifying the compiler like this, so please be extra 
careful with my patch. I believe I understand most of what I did, but I might 
have misunderstood. :)

> The patch has no testcases; it should probably add test coverage for:
> - the various places and ways in which diagnose_as can affect the
> output,
> - disabling it with the option
> - the various ways in which the user can get diagnose_as wrong
> - etc

Right. If you know of an existing similar testcase, that'd help me a lot to 
get started.

> Does the patch affect the output of labels when underlining ranges of
> source code in diagnostics?

AFAIU (and tested), it doesn't affect source code output. So, no?

> Does the patch interact correctly with the %H and %I codes that try to
> show the differences between two template types?

I don't know. I'll try to find out. If you have a good idea (or pointer) for a 
testcase, let me know.

> I have some minor nits from a diagnostics point of view:
> [...]
> Please add an auto_diagnostic_group here so that the "inform" is
> associated with the "error".
> [...]
> diagnose_as should be in quotes here (%< and %>).
> [...]
> Please quote extern "C":

Thanks. All done in my tree. I'll work on testcases before sending an updated 
patch.

> Thanks again for the patch; hope this is constructive

👍


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 Dr. Matthias Kretz                           https://mattkretz.github.io
 GSI Helmholtz Centre for Heavy Ion Research               https://gsi.de
 std::experimental::simd              https://github.com/VcDevel/std-simd
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