linux-kernel - Re: [PATCH v8] checkkconfigsymbols.sh: reimplementation in python

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Message-ID: <542C1692.5060007@suse.cz>
Date:	Wed, 01 Oct 2014 16:58:26 +0200
From:	Michal Marek <mmarek@...e.cz>
To:	Valentin Rothberg <valentinrothberg@...il.com>
CC:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	linux-kbuild@...r.kernel.org, pebolle@...cali.nl,
	Stefan Hengelein <stefan.hengelein@....de>
Subject: Re: [PATCH v8] checkkconfigsymbols.sh: reimplementation in python

On 2014-09-29 19:05, Valentin Rothberg wrote:
> The scripts/checkkconfigsymbols.sh script searches Kconfig features
> in the source code that are not defined in Kconfig. Such identifiers
> always evaluate to false and are the source of various kinds of bugs.
> However, the shell script is slow and it does not detect such broken
> references in Kbuild and Kconfig files (e.g., ``depends on UNDEFINED´´).
> Furthermore, it generates false positives. The script is also hard to
> read and understand, and is thereby difficult to maintain.
> 
> This patch replaces the shell script with an implementation in Python,
> which:
>     (a) detects the same bugs, but does not report previous false positives
>     (b) additionally detects broken references in Kconfig and all
>         non-Kconfig files, such as Kbuild, .[cSh], .txt, .sh, defconfig, etc.
>     (c) is up to 75 times faster than the shell script
>     (d) only checks files under version control ('git ls-files')
> 
> The new script reduces the runtime on my machine (i7-2620M, 8GB RAM, SSD)
> from 3m47s to 0m3s, and reports 912 broken references in Linux v3.17-rc1;
> 424 additional reports of which 16 are located in Kconfig files,
> 287 in defconfigs, 63 in ./Documentation, 1 in Kbuild.
> 
> Moreover, we intentionally include references in comments, which have been
> ignored until now. Such comments may be leftovers of features that have
> been removed or renamed in Kconfig (e.g., ``#endif /* CONFIG_MPC52xx */´´).
> These references can be misleading and should be removed or replaced.
> 
> Note that the output format changed from (file list <tab> feature) to
> (feature <tab> file list) as it simplifies the detection of the Kconfig
> feature for long file lists.
> 
> Signed-off-by: Valentin Rothberg <valentinrothberg@...il.com>
> Signed-off-by: Stefan Hengelein <stefan.hengelein@....de>
> Acked-by: Paul Bolle <pebolle@...cali.nl>
> ---
> Changelog:
> v2: Fix of regular expressions
> v3: Changelog replacement, and add changes of v2
> v4: Based on comments from Paul Bolle <pebolle@...cali.nl>
>   - Inclusion of all non-Kconfig files, such as .txt, .sh, etc.
>   - Changes of regular expressions
>   - Increases additional reports from 49 to 229 compared to v3
>   - Change of output format from (file list <tab> feature) to
>         (feature <tab> file list)
> v5: Only analyze files under version control ('git ls-files')
> v6: Cover features with numbers and small letters (e.g., 4xx)
> v7: Add changes of v6 (lost 'git add') and filter FOO/BAR features
> v8: Based on comments from Paul Bolle <pebolle@...cali.nl>
>   - Fix of [D]{,1}CONFIG_ regex to exclude false positives
>   - Exclude ".log" files of analysis
>   - Filter "XXX" feature
> ---
>  scripts/checkkconfigsymbols.py | 139 +++++++++++++++++++++++++++++++++++++++++
>  scripts/checkkconfigsymbols.sh |  59 -----------------
>  2 files changed, 139 insertions(+), 59 deletions(-)
>  create mode 100644 scripts/checkkconfigsymbols.py
>  delete mode 100755 scripts/checkkconfigsymbols.sh

Please make the new file executable as well.


> +    for gitfile in stdout.rsplit("\n"):
> +        if ".git" in gitfile or "ChangeLog" in gitfile or \
> +                ".log" in gitfile or os.path.isdir(gitfile):
> +            continue

Can you also skip arch/*/configs? A significant part of the output are
defconfig files, but there is little value in reporting them. The stale
options will go away automatically as soon as the defconfig is refreshed.

Michal
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