linux-kernel - Re: [PATCH] scripts: reduce false positives in the macro

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Message-ID: <CAHB1NagCqP4k9XvmAoyZ8NaRb0Y-bT1unnnOsmnt-mE6_k=8Rg@mail.gmail.com>
Date: Thu, 25 Jul 2024 05:15:34 -0400
From: Julian Sun <sunjunchao2870@...il.com>
To: Jan Kara <jack@...e.cz>
Cc: linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, linux-kbuild@...r.kernel.org, 
	brauner@...nel.org, viro@...iv.linux.org.uk, masahiroy@...nel.org, 
	akpm@...ux-foundation.org, n.schier@....de, ojeda@...nel.org, 
	djwong@...nel.org, kvalo@...nel.org
Subject: Re: [PATCH] scripts: reduce false positives in the macro_checker script.

Jan Kara <jack@...e.cz> 于2024年7月25日周四 04:52写道：
>
> On Thu 25-07-24 03:58:30, Julian Sun wrote:
> > Reduce false positives in the macro_checker
> > in the following scenarios:
> >   1. Conditional compilation
> >   2. Macro definitions with only a single character
> >   3. Macro definitions as (0) and (1)
> >
> > Before this patch:
> >       sjc@sjc:linux$ ./scripts/macro_checker.py  fs | wc -l
> >       99
> >
> > After this patch:
> >       sjc@sjc:linux$ ./scripts/macro_checker.py  fs | wc -l
> >       11
> >
> > Most of the current warnings are valid now.
> >
> > Signed-off-by: Julian Sun <sunjunchao2870@...il.com>
> ...
> >  def file_check_macro(file_path, report):
> > +    # number of conditional compiling
> > +    cond_compile = 0
> >      # only check .c and .h file
> >      if not file_path.endswith(".c") and not file_path.endswith(".h"):
> >          return
> > @@ -57,7 +72,14 @@ def file_check_macro(file_path, report):
> >          while True:
> >              line = f.readline()
> >              if not line:
> > -                return
> > +                break
> > +            line = line.strip()
> > +            if line.startswith(cond_compile_mark):
> > +                cond_compile += 1
> > +                continue
> > +            if line.startswith(cond_compile_end):
> > +                cond_compile -= 1
> > +                continue
> >
> >              macro = re.match(macro_pattern, line)
> >              if macro:
> > @@ -67,6 +89,11 @@ def file_check_macro(file_path, report):
> >                      macro = macro.strip()
> >                      macro += f.readline()
> >                      macro = macro_strip(macro)
> > +                if file_path.endswith(".c")  and cond_compile != 0:
> > +                    continue
> > +                # 1 is for #ifdef xxx at the beginning of the header file
> > +                if file_path.endswith(".h") and cond_compile != 1:
> > +                    continue
> >                  check_macro(macro, report)
> >
> >  def get_correct_macros(path):
>
>
> > So I don't think this is right. As far as I understand this skips any macros
> > that are conditionally defined? Why? There is a lot of them and checking
> > them is beneficial... The patterns you have added should be dealing with
> > most of the conditional defines anyway.
Yes, this skips all checks for conditional macro. This is because I
observed that almost all false positives come from conditional
compilation. Testing showed that skipping them does not cause the
genuine warnings to disappear.
Also as you said, it may still lead to skipping checks for genuinely
problematic macro definitions. Perhaps we could provide an option that
allows users to control whether or not to check macros under
conditional compilation?
>
>                                                                 Honza
> --
> Jan Kara <jack@...e.com>
> SUSE Labs, CR


Thanks,
-- 
Julian Sun <sunjunchao2870@...il.com>