RE: [PATCH] devtools: stop compiler atomics with no C11 equivalent

["Morten Brørup" <mb@smartsharesystems.com>]

> From: Tyler Retzlaff [mailto:roretzla@linux.microsoft.com]
> Sent: Wednesday, 22 March 2023 22.00
> 
> On Wed, Mar 22, 2023 at 07:25:09PM +0100, Morten Brørup wrote:
> > > From: Tyler Retzlaff [mailto:roretzla@linux.microsoft.com]
> > > Sent: Wednesday, 22 March 2023 19.08
> > >
> > > adding a few more people to cc for attention
> > >
> > > On Mon, Mar 20, 2023 at 09:22:01AM -0700, Tyler Retzlaff wrote:
> > > > Refrain from using compiler
> __atomic_{add,and,nand,or,sub,xor}_fetch()
> > > > to ease future adoption of C11 standard atomics.
> > > >
> > > > Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
> > > > ---
> > > >  devtools/checkpatches.sh | 8 ++++++++
> > > >  1 file changed, 8 insertions(+)
> > > >
> > > > diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> > > > index 1dee094..1ed6d51 100755
> > > > --- a/devtools/checkpatches.sh
> > > > +++ b/devtools/checkpatches.sh
> > > > @@ -119,6 +119,14 @@ check_forbidden_additions() { # <patch>
> > > >  		-f $(dirname $(readlink -f $0))/check-forbidden-
> tokens.awk
> > > \
> > > >  		"$1" || res=1
> > > >
> > > > +	# refrain from using compiler
> > > __atomic_{add,and,nand,or,sub,xor}_fetch()
> > > > +	awk -v FOLDERS="lib drivers app examples" \
> > > > +		-v
> > > EXPRESSIONS="__atomic_(add|and|nand|or|sub|xor)_fetch\\\(" \
> > > > +		-v RET_ON_FAIL=1 \
> > > > +		-v MESSAGE='Using
> __atomic_{add,and,nand,or,sub,xor}_fetch'
> > > \
> >
> > Suggest that you expand the error message with a solution for the
> developer: "... use __atomic_fetch_op() instead of __atomic_op_fetch()"
> 
> if awk could expand captures i would do that but it can't.
> 
> or do you mean literally use 'op' instead of {add,and,nand,or,sub,xor}
> in the message?

I didn't think about expansion, so literally using "op" in the solution part of the message is exactly what I meant. But please keep the existing part of the message as is.

Alternatively, you can also use "{add,and,nand,or,sub,xor}" instead of "op" in the solution part of the message. Whatever you prefer.

The message could be even more verbose by also adding the reason why __atomic_op_fetch() is prohibited, such as: "... in order to prepare for conversion to C11 stdatomics, where atomic_{add,and,nand,or,sub,xor}_fetch() is unavailable."

> 
> >
> > > > +		-f $(dirname $(readlink -f $0))/check-forbidden-
> tokens.awk
> > > \
> > > > +		"$1" || res=1
> > > > +
> > > >  	# forbid use of __reserved which is a reserved keyword in
> Windows
> > > system headers
> > > >  	awk -v FOLDERS="lib drivers app examples" \
> > > >  		-v EXPRESSIONS='\\<__reserved\\>' \
> > > > --
> > > > 1.8.3.1