[PATCH v2 11/16] perf parse-events: Improve error message for bad numbers

[Ian Rogers]

On Fri, Apr 26, 2024 at 6:36 PM Arnaldo Carvalho de Melo
<acme at kernel.org> wrote:
>
> On Fri, Apr 26, 2024 at 10:36:02PM -0300, Arnaldo Carvalho de Melo wrote:
> > On Mon, Apr 15, 2024 at 11:15:27PM -0700, Ian Rogers wrote:
> > > Use the error handler from the parse_state to give a more informative
> > > error message.
> > >
> > > Before:
> > > ```
> > > $ perf stat -e 'cycles/period=99999999999999999999/' true
> > > event syntax error: 'cycles/period=99999999999999999999/'
> > >                                   \___ parser error
> > > Run 'perf list' for a list of valid events
> > >
> > >  Usage: perf stat [<options>] [<command>]
> > >
> > >     -e, --event <event>   event selector. use 'perf list' to list available events
> > > ```
> > >
> > > After:
> > > ```
> > > $ perf stat -e 'cycles/period=99999999999999999999/' true
> > > event syntax error: 'cycles/period=99999999999999999999/'
> > >                                   \___ parser error
> > >
> >
> > This ended up in perf-tools-next, will have to look at what this problem
> > is:
> >
> >    9    11.46 amazonlinux:2                 : FAIL gcc version 7.3.1 20180712 (Red Hat 7.3.1-17) (GCC)
> >      yy_size_t parse_events_get_leng (yyscan_t yyscanner );
> >                ^~~~~~~~~~~~~~~~~~~~~
> >     util/parse-events.l:22:5: note: previous declaration of 'parse_events_get_leng' was here
> >      int parse_events_get_leng(yyscan_t yyscanner);
> >          ^~~~~~~~~~~~~~~~~~~~~
> >      yy_size_t parse_events_get_leng  (yyscan_t yyscanner)
> >                ^~~~~~~~~~~~~~~~~~~~~
> >     util/parse-events.l:22:5: note: previous declaration of 'parse_events_get_leng' was here
> >      int parse_events_get_leng(yyscan_t yyscanner);
> >          ^~~~~~~~~~~~~~~~~~~~~
> >     make[3]: *** [util] Error 2
> >
> >
> > Unsure if this will appear on the radar on other distros, maybe this is
> > just something that pops up with older distros...
> >
> > Ran out of time today...
>
> Context:
>
> perfbuilder at number:~$ export BUILD_TARBALL=http://192.168.86.42/perf/perf-6.9.0-rc5.tar.xz
> perfbuilder at number:~$ time dm
>    1   102.33 almalinux:8                   : Ok   gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-20) , clang version 16.0.6 (Red Hat 16.0.6-2.module_el8.9.0+3621+df7f7146) flex 2.6.1
>    2   102.44 almalinux:9                   : Ok   gcc (GCC) 11.4.1 20230605 (Red Hat 11.4.1-2) , clang version 16.0.6 (Red Hat 16.0.6-1.el9) flex 2.6.4
>    3   124.34 alpine:3.15                   : Ok   gcc (Alpine 10.3.1_git20211027) 10.3.1 20211027 , Alpine clang version 12.0.1 flex 2.6.4
>    4   109.42 alpine:3.16                   : Ok   gcc (Alpine 11.2.1_git20220219) 11.2.1 20220219 , Alpine clang version 13.0.1 flex 2.6.4
>    5    90.08 alpine:3.17                   : Ok   gcc (Alpine 12.2.1_git20220924-r4) 12.2.1 20220924 , Alpine clang version 15.0.7 flex 2.6.4
>    6    84.85 alpine:3.18                   : Ok   gcc (Alpine 12.2.1_git20220924-r10) 12.2.1 20220924 , Alpine clang version 16.0.6 flex 2.6.4
>    7    94.18 alpine:3.19                   : Ok   gcc (Alpine 13.2.1_git20231014) 13.2.1 20231014 , Alpine clang version 17.0.5 flex 2.6.4
>    8    95.45 alpine:edge                   : Ok   gcc (Alpine 13.2.1_git20240309) 13.2.1 20240309 , Alpine clang version 17.0.6 flex 2.6.4
>    9    11.46 amazonlinux:2                 : FAIL gcc version 7.3.1 20180712 (Red Hat 7.3.1-17) (GCC)
>      yy_size_t parse_events_get_leng (yyscan_t yyscanner );
>                ^~~~~~~~~~~~~~~~~~~~~
>     util/parse-events.l:22:5: note: previous declaration of 'parse_events_get_leng' was here
>      int parse_events_get_leng(yyscan_t yyscanner);
>          ^~~~~~~~~~~~~~~~~~~~~
>      yy_size_t parse_events_get_leng  (yyscan_t yyscanner)
>                ^~~~~~~~~~~~~~~~~~~~~
>     util/parse-events.l:22:5: note: previous declaration of 'parse_events_get_leng' was here
>      int parse_events_get_leng(yyscan_t yyscanner);
>          ^~~~~~~~~~~~~~~~~~~~~
>     make[3]: *** [util] Error 2
>   10    88.41 amazonlinux:2023              : Ok   gcc (GCC) 11.4.1 20230605 (Red Hat 11.4.1-2) , clang version 15.0.7 (Amazon Linux 15.0.7-3.amzn2023.0.1) flex 2.6.4
>   11    89.72 amazonlinux:devel             : Ok   gcc (GCC) 11.3.1 20221121 (Red Hat 11.3.1-4) , clang version 15.0.6 (Amazon Linux 15.0.6-3.amzn2023.0.2) flex 2.6.4
>   12   115.65 archlinux:base                : Ok   gcc (GCC) 13.2.1 20230801 , clang version 17.0.6 flex 2.6.4
>   13    93.87 centos:stream                 : Ok   gcc (GCC) 8.5.0 20210514 (Red Hat 8.5.0-21) , clang version 17.0.6 (Red Hat 17.0.6-1.module_el8+767+9fa966b8) flex 2.6.1

Did RedHat do value add on flex output? yyget_leng is documented to
have an int return type:
https://github.com/westes/flex/blob/master/doc/flex.texi#L4613
This patch just adds a forward declaration in order to use it in a
helper function.

Thanks,
Ian