* [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message
@ 2021-09-04 7:42 Utkarsh Verma
2021-09-14 21:07 ` Jonathan Corbet
0 siblings, 1 reply; 4+ messages in thread
From: Utkarsh Verma @ 2021-09-04 7:42 UTC (permalink / raw)
To: Dwaipayan Ray
Cc: Lukas Bulwahn, Joe Perches, Jonathan Corbet, linux-doc,
linux-kernel, Utkarsh Verma
Add a new message type TRAILING_SEMICOLON for the macro definitions
that conclude with a semicolon.
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Utkarsh Verma <utkarshverma294@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 f0956e9ea2d8..30eda8f4a8bd 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 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/
+
**WEAK_DECLARATION**
Using weak declarations like __attribute__((weak)) or __weak
can have unintended link defects. Avoid using them.
--
2.25.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message
2021-09-04 7:42 [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message Utkarsh Verma
@ 2021-09-14 21:07 ` Jonathan Corbet
0 siblings, 0 replies; 4+ messages in thread
From: Jonathan Corbet @ 2021-09-14 21:07 UTC (permalink / raw)
To: Utkarsh Verma, Dwaipayan Ray
Cc: Lukas Bulwahn, Joe Perches, linux-doc, linux-kernel, Utkarsh Verma
Utkarsh Verma <utkarshverma294@gmail.com> writes:
> Add a new message type TRAILING_SEMICOLON for the macro definitions
> that conclude with a semicolon.
>
> Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> Signed-off-by: Utkarsh Verma <utkarshverma294@gmail.com>
> ---
> Documentation/dev-tools/checkpatch.rst | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
Applied, thanks.
jon
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message
2021-08-03 14:20 ` [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message Utkarsh Verma
@ 2021-08-03 15:20 ` Dwaipayan Ray
0 siblings, 0 replies; 4+ messages in thread
From: Dwaipayan Ray @ 2021-08-03 15:20 UTC (permalink / raw)
To: Utkarsh Verma; +Cc: linux-kernel-mentees
On Tue, Aug 3, 2021 at 7:50 PM Utkarsh Verma <utkarshverma294@gmail.com> wrote:
>
> Add a new message type TRAILING_SEMICOLON for the macro definitions
> that conclude with a semicolon.
>
> Signed-off-by: Utkarsh Verma <utkarshverma294@gmail.com>
> Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
> ---
> Documentation/dev-tools/checkpatch.rst | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
> index f0956e9ea..504edd961 100644
> --- a/Documentation/dev-tools/checkpatch.rst
> +++ b/Documentation/dev-tools/checkpatch.rst
> @@ -845,6 +845,26 @@ 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. A function
> + call concludes with a semicolon, so the macro invocation must also
> + conclude with a semicolon. Suppose if a macro MAC is defined::
The objective is really to avoid unexpected code paths. The explanation
seems correct but can be shortened a bit?
These two sentences can be combined:
The macro invocation should be consistent with the function call. A function
call concludes with a semicolon (We already know this right?), so the
macro invocation
must also conclude with a semicolon.
Also let's add link to the discussion which introduced it:
https://lore.kernel.org/lkml/alpine.DEB.2.02.1405092345480.6261@ionos.tec.linutronix.de/
> +
> + #define MAC \
> + do_something;
combine it in one line?
> +
> + If this macro is used within a if else statement, like::
> +
> + if(some_condition)
space after if
> + 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.
> +
> **WEAK_DECLARATION**
> Using weak declarations like __attribute__((weak)) or __weak
> can have unintended link defects. Avoid using them.
> --
> 2.17.1
>
Dwaipayan.
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message
2021-07-26 10:40 Linux Kernel: Checkpatch Documentation Mentorship Tasks Lukas Bulwahn
@ 2021-08-03 14:20 ` Utkarsh Verma
2021-08-03 15:20 ` Dwaipayan Ray
0 siblings, 1 reply; 4+ messages in thread
From: Utkarsh Verma @ 2021-08-03 14:20 UTC (permalink / raw)
To: Lukas Bulwahn; +Cc: Dwaipayan Ray, linux-kernel-mentees
Add a new message type TRAILING_SEMICOLON for the macro definitions
that conclude with a semicolon.
Signed-off-by: Utkarsh Verma <utkarshverma294@gmail.com>
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
---
Documentation/dev-tools/checkpatch.rst | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
index f0956e9ea..504edd961 100644
--- a/Documentation/dev-tools/checkpatch.rst
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -845,6 +845,26 @@ 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. A function
+ call concludes with a semicolon, so the macro invocation must also
+ conclude with a semicolon. Suppose if a macro MAC is defined::
+
+ #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.
+
**WEAK_DECLARATION**
Using weak declarations like __attribute__((weak)) or __weak
can have unintended link defects. Avoid using them.
--
2.17.1
_______________________________________________
Linux-kernel-mentees mailing list
Linux-kernel-mentees@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
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2021-09-04 7:42 [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message Utkarsh Verma
2021-09-14 21:07 ` Jonathan Corbet
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2021-07-26 10:40 Linux Kernel: Checkpatch Documentation Mentorship Tasks Lukas Bulwahn
2021-08-03 14:20 ` [PATCH] Documentation: checkpatch: Add TRAILING_SEMICOLON message Utkarsh Verma
2021-08-03 15:20 ` Dwaipayan Ray
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