Re: [cocci] Improving output for single characters (with SmPL)?

Markus Elfring <[email protected]> Thu, 23 Jul 2026 21:26:15 +0200
Newsgroups fr.inria.cocci,org.kernel.vger.kernel-janitors,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
> I would like to achieve further source code adjustments by the means of
> the following script variant for the semantic patch language.

Unfortunately, the SmPL code needs to be corrected a bit in the final
replacement rule.
The parameter order should be reversed from selected fprintf() to fputc() =
calls.

@initialize:python@
@@
input =3D ''

def convert(item):
   mark =3D ["'", item, "'"]
   coccinelle.text =3D cocci.make_expr(''.join(mark))

def common_checks(unescaped):
   if input[1] =3D=3D '"':
      if input[2:] =3D=3D '':
         convert(input[0] if unescaped else '\\' + input[0])
      else:
         cocci.include_match(False)
   else:
      cocci.include_match(False)

@find_update_candidate@
constant char[] input_string;
expression input_context;
position pos;
@@
 fprintf@pos(input_context, input_string);

@script:python selection@
param << find_update_candidate.input_string;
text;
@@
if param[0] =3D=3D '"':
   input =3D param[1:]
   if input[0] =3D=3D '\\':
      input =3D input[1:]
      if input[0] =3D=3D '"':
         if input[1] =3D=3D '"':
            if input[2:] =3D=3D '':
               convert('"')
            else:
               cocci.include_match(False)
         else:
            cocci.include_match(False)
      else:
         common_checks(False)
   else:
      common_checks(True)
else:
   cocci.include_match(False)

@replacement@
constant char[] find_update_candidate.input_string, selection.text;
expression find_update_candidate.input_context;
position find_update_candidate.pos;
@@
(
-fprintf@pos
+putchar
 (
-stdout,
-input_string
+text
 )
|
-fprintf@pos
+fputc
 (
-input_context
+text
 ,
-input_string
+input_context
 )
)


Another test result (according to the software combination =E2=80=9CCoccin=
elle 1.3.1=E2=80=9D):
Markus_Elfring@Sonne:=E2=80=A6/Projekte/Linux/next-analyses> time /usr/bin=
/spatch --timeout 23  -j4 --chunksize 1 --no-loops --include-headers -dir =
tools =E2=80=A6/Projekte/Coccinelle/janitor/use_fputc-20260723.cocci > =E2=
=80=A6/Projekte/Bau/Linux/scripts/Coccinelle/tuning1/next/20260721/use_fpu=
tc.diff
=E2=80=A6
548 files match
=E2=80=A6
real    0m35,324s
user    1m54,532s
sys     0m3,473s
Markus_Elfring@Sonne:/home/altes_Heim2/elfring/Projekte/Linux/next-analyse=
s> lsdiff /home/altes_Heim2/elfring/Projekte/Bau/Linux/scripts/Coccinelle/=
tuning1/next/20260721/use_fputc.diff | wc -l
50



I hope that demonstrated data processing possibilities can influence furth=
er
development ideas in constructive ways besides hints that some compilers
can also perform such a source code transformation already.

Regards,
Markus