From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: Miika <nykseli@protonmail.com>
Cc: Ben Boeckel <ben.boeckel@kitware.com>,
"gcc@gcc.gnu.org" <gcc@gcc.gnu.org>
Subject: Re: [RFC] Support for nonzero attribute
Date: Tue, 7 Jun 2022 20:46:13 +0100 [thread overview]
Message-ID: <CAH6eHdSbfYfy73GJ+vNd8VZpqTCXFoXCG9oXun51AEn93ZEyWw@mail.gmail.com> (raw)
In-Reply-To: <CAH6eHdTNXafW-sD5KnE9===xQDzsJzO-=KprLmHCUqxdQ=tXNw@mail.gmail.com>
On Tue, 7 Jun 2022 at 20:44, Jonathan Wakely wrote:
>
> On Tue, 7 Jun 2022 at 20:40, Miika via Gcc <gcc@gcc.gnu.org> wrote:
> >
> > On Monday, June 6th, 2022 at 9:42 PM, Ben Boeckel <ben.boeckel@kitware.com> wrote:
> > > > Based on Jakub's and Yair's comments I created a new attribute "inrange".
> > > > Inrage takes three arguments, pos min and max.
> > > > Pos being the argument position in the function, and min and max defines the
> > > > range of valid integer. Both min and max are inclusive and work with enums.
> > > > Warnings are enabled with the new flag: "-Winrange".
> > >
> > >
> > > Is this something that could be applied to variables or types (I've not
> > > much experience with GCC attribute internal mechanisms, so maybe not)?
> >
> > I took a closer look at it and looks like it can be applied.
> >
> > So trying to compile this:
> > ```
> > typedef int __attribute__((inrange(0, 100))) percentage_t;
> > int main() {
> > int percentage __attribute__((inrange(0, 100))) = -1;
> > percentage_t per __attribute__((inrange(0, 100))) = -1;
> > }
> > ```
> >
> > Would print out something like this:
> >
> > foo.c: In function 'main':
> > foo.c:3:59: warning: inrange variable 'percentage' requires integer in rage of 0..100 [-Winrange]
>
> N.B. "rage" should be "range".
>
> From the diagnostic it's not clear to me whether this is an inclusive
> range. Is 0 allowed? Is 100 allowed?
>
> Using [0,100] interval notation would imply both endpoints are valid,
> which I think matches the semantics of your attribute. Is interval
> notation sufficiently widely understood to use here?
Oh, Wikipedia tells me that 0..100 already means that, as an integer interval:
https://en.wikipedia.org/wiki/Interval_(mathematics)#Integer_intervals
So maybe it's fine as-is (except for the "rage" typo).
next prev parent reply other threads:[~2022-06-07 19:46 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-03 16:34 Miika
2022-06-03 16:45 ` Jakub Jelinek
2022-06-04 11:25 ` Miika
2022-06-05 20:09 ` Miika
2022-06-06 18:42 ` Ben Boeckel
2022-06-07 19:39 ` Miika
2022-06-07 19:44 ` Jonathan Wakely
2022-06-07 19:46 ` Jonathan Wakely [this message]
2022-06-07 19:56 ` Miika
2022-06-08 17:42 ` Eric Gallager
2022-06-08 20:59 ` Miika
2022-06-09 4:36 ` Eric Gallager
2022-06-09 18:06 ` Miika
2022-06-12 4:25 ` Prathamesh Kulkarni
2022-06-13 12:55 ` Miika
2022-06-13 16:02 ` Martin Sebor
[not found] <mailman.2312.1654300374.1672222.gcc@gcc.gnu.org>
2022-06-04 10:26 ` Yair Lenga
2022-06-04 11:55 ` Miika
2022-06-04 21:29 ` Yair Lenga
2022-06-13 9:49 ` Richard Biener
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