[PATCH v2] Documentation: checkpatch: Add TRAILING_SEMICOLON message
dwaipayanray1 at gmail.com
Thu Aug 5 13:49:10 UTC 2021
On Wed, Aug 4, 2021 at 2:50 AM Utkarsh Verma <utkarshverma294 at gmail.com> wrote:
> Add a new message type TRAILING_SEMICOLON for the macro definitions
> that conclude with a semicolon.
> Suggested-by: Lukas Bulwahn <lukas.bulwahn at gmail.com>
> Signed-off-by: Utkarsh Verma <utkarshverma294 at gmail.com>
> Documentation/dev-tools/checkpatch.rst | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
> diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
> index f0956e9ea..f2ef998ba 100644
> --- a/Documentation/dev-tools/checkpatch.rst
> +++ b/Documentation/dev-tools/checkpatch.rst
> @@ -845,6 +845,27 @@ Macros, Attributes and Symbols
> Use the `fallthrough;` pseudo keyword instead of
> `/* fallthrough */` like comments.
> + **TRAILING_SEMICOLON**
> + Macro definition should not conclude with a semicolon. The macro
> + invocation should be consistent with the function call. So the macro
> + invocation must conclude with a semicolon. Suppose if a macro MAC is
> + defined::
Macro definition should not end with a semicolon. The macro
invocation style should be consistent with function calls.
This can prevent any unexpected code paths.
> + #define MAC do_something;
> + If this macro is used within a if else statement, like::
> + if (some_condition)
> + MAC;
> + else
> + do_something;
> + Then there would be a compilation error, because when the macro is
> + expanded there are two trailing semicolons, so the else branch gets
> + orphaned.
> + See: https://lore.kernel.org/lkml/1399671106.2912.21.camel@joe-AO725/
> Using weak declarations like __attribute__((weak)) or __weak
> can have unintended link defects. Avoid using them.
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