From: David Malcolm <dmalcolm@redhat.com>
To: Matthias Kretz <m.kretz@gsi.de>, gcc-patches@gcc.gnu.org
Cc: libstdc++@gcc.gnu.org
Subject: Re: [PATCH] Add gnu::diagnose_as attribute
Date: Tue, 04 May 2021 09:34:13 -0400 [thread overview]
Message-ID: <72d4620b42f3bdbb3eab94a46ccc0434ed160fe0.camel@redhat.com> (raw)
In-Reply-To: <91863212.B8guWdUDZo@excalibur>
On Tue, 2021-05-04 at 13:13 +0200, Matthias Kretz wrote:
> From: Matthias Kretz <kretz@kde.org>
>
> 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.
>
> On Tuesday, 27 April 2021 11:46:48 CEST Jonathan Wakely wrote:
> > I think it's a great idea and would like to use it for all the TS
> > implementations where there is some inline namespace that the user
> > doesn't care about. std::experimental::fundamentals_v1:: would be
> > much
> > better as just std::experimental::, or something like std::[LFTS]::.
>
> With the attribute, it is possible to solve PR89370 and make
> std::__cxx11::basic_string<_CharT, _Traits, _Alloc> appear as
> std::string in diagnostic output without extra hacks to recognize the
> type.
Thanks for the patch, it looks very promising.
The C++ frontend maintainers will need to review the C++ frontend parts
in detail, so I'll defer to them for the bulk of the review.
Various thoughts:
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
Does the patch affect the output of labels when underlining ranges of
source code in diagnostics?
Does the patch interact correctly with the %H and %I codes that try to
show the differences between two template types?
I have some minor nits from a diagnostics point of view:
[...snip...]
> diff --git a/gcc/cp/name-lookup.c b/gcc/cp/name-lookup.c
> index 4e84e2f9987..80637503310 100644
> --- a/gcc/cp/name-lookup.c
> +++ b/gcc/cp/name-lookup.c
[...]
> + tree existing
> + = lookup_attribute ("diagnose_as", DECL_ATTRIBUTES (ns));
> + if (existing
> + && !cp_tree_equal(TREE_VALUE (args),
> + TREE_VALUE (TREE_VALUE (existing))))
> + {
Please add an auto_diagnostic_group here so that the "inform" is
associated with the "error".
> + error ("the namespace %qE already uses a different diagnose_as "
> + "attribute value", ns);
diagnose_as should be in quotes here (%< and %>).
> + inform (DECL_SOURCE_LOCATION (ns), "previous declaration here");
> + continue;
> + }
> + DECL_ATTRIBUTES (ns) = tree_cons (name, args,
> + DECL_ATTRIBUTES (ns));
> + }
> else
> {
> warning (OPT_Wattributes, "%qD attribute directive ignored",
> diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
> index a8bfd5fc053..f7b93dc89d7 100644
> --- a/gcc/cp/tree.c
> +++ b/gcc/cp/tree.c
[...snip...]
> + else if (DECL_LANGUAGE (*node) == lang_c)
> + {
> + error ("%qE attribute applied to extern \"C\" declaration %qD",
Please quote extern "C":
%<extern \"C\"%>
> + name, *node);
[...snip...]
Thanks again for the patch; hope this is constructive
Dave
next prev parent reply other threads:[~2021-05-04 13:34 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <14205410.xuKvIAzr1H@excalibur>
[not found] ` <20210427094648.GL3008@redhat.com>
2021-05-04 11:13 ` Matthias Kretz
2021-05-04 13:34 ` David Malcolm [this message]
2021-05-04 14:23 ` Matthias Kretz
2021-05-04 14:32 ` Matthias Kretz
2021-05-04 19:00 ` David Malcolm
2021-05-04 19:22 ` Matthias Kretz
2021-05-14 16:05 ` Martin Sebor
2021-05-26 21:33 ` Matthias Kretz
2021-05-27 17:39 ` Jason Merrill
2021-05-27 18:54 ` Matthias Kretz
2021-05-27 21:15 ` Jason Merrill
2021-05-27 22:07 ` Matthias Kretz
2021-05-28 3:05 ` Jason Merrill
2021-05-28 7:42 ` Matthias Kretz
2021-06-01 19:12 ` Jason Merrill
2021-06-01 21:01 ` Matthias Kretz
2021-06-11 10:01 ` Matthias Kretz
2021-06-15 15:51 ` Jason Merrill
2021-06-15 20:56 ` Matthias Kretz
2021-06-16 0:48 ` Jason Merrill
2021-06-22 7:30 ` Matthias Kretz
2021-06-22 19:52 ` Jason Merrill
2021-06-22 20:01 ` Matthias Kretz
2021-06-22 20:12 ` Jason Merrill
2021-07-01 9:28 ` Matthias Kretz
2021-07-01 15:18 ` Jason Merrill
2021-07-05 14:18 ` Matthias Kretz
2021-07-07 22:34 ` Jason Merrill
2021-07-07 8:23 ` Matthias Kretz
2021-07-08 1:19 ` Jason Merrill
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