2011-04-05 15:01:05

by Michal Marek

Subject: [PATCH 34/34] checkpatch: Warn about usage of __DATE__, __TIME__ and __TIMESTAMP__

The __TIME__ and __DATE__ macros are evil. Every C textbook mentions
them, but forgets to add the tiny detail that they make sure that your
code will never result in the same binary. __TIMESTAMP__ is a bit more
sane, but again produces noise as soon as you switch branches back and
forth, or apply a patch and revert it.

Cc: Andy Whitcroft <[email protected]>
Signed-off-by: Michal Marek <[email protected]>
---
scripts/checkpatch.pl | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4c0383d..dbcdf04 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2804,6 +2804,11 @@ sub process {
WARN("__func__ should be used instead of gcc specific __FUNCTION__\n" . $herecurr);
}

+# check for pointless usage of __TIME__ and friends
+ if ($line =~ /\b__(TIME|DATE|TIMESTAMP)__\b/) {
+ WARN("Usage of __$1__ should be avoided to keep the build deterministic\n" . $herecurr);
+ }
+
# check for semaphores initialized locked
if ($line =~ /^.\s*sema_init.+,\W?0\W?\)/) {
WARN("consider using a completion\n" . $herecurr);
--
1.7.4.1

2011-05-26 11:39:18

by Michal Marek

Subject: Re: [PATCH 34/34] checkpatch: Warn about usage of __DATE__, __TIME__ and __TIMESTAMP__

On 5.4.2011 16:59, Michal Marek wrote:
> The __TIME__ and __DATE__ macros are evil. Every C textbook mentions
> them, but forgets to add the tiny detail that they make sure that your
> code will never result in the same binary. __TIMESTAMP__ is a bit more
> sane, but again produces noise as soon as you switch branches back and
> forth, or apply a patch and revert it.
>
> Cc: Andy Whitcroft <[email protected]>
> Signed-off-by: Michal Marek <[email protected]>
> ---
> scripts/checkpatch.pl | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)

Hi Andy,

any comments about this patch?

Thanks,
Michal


> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 4c0383d..dbcdf04 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2804,6 +2804,11 @@ sub process {
> WARN("__func__ should be used instead of gcc specific __FUNCTION__\n" . $herecurr);
> }
>
> +# check for pointless usage of __TIME__ and friends
> + if ($line =~ /\b__(TIME|DATE|TIMESTAMP)__\b/) {
> + WARN("Usage of __$1__ should be avoided to keep the build deterministic\n" . $herecurr);
> + }
> +
> # check for semaphores initialized locked
> if ($line =~ /^.\s*sema_init.+,\W?0\W?\)/) {
> WARN("consider using a completion\n" . $herecurr);

2011-05-26 12:42:27

by Andy Whitcroft

Subject: Re: [PATCH 34/34] checkpatch: Warn about usage of __DATE__, __TIME__ and __TIMESTAMP__

On Tue, Apr 05, 2011 at 04:59:21PM +0200, Michal Marek wrote:
> The __TIME__ and __DATE__ macros are evil. Every C textbook mentions
> them, but forgets to add the tiny detail that they make sure that your
> code will never result in the same binary. __TIMESTAMP__ is a bit more
> sane, but again produces noise as soon as you switch branches back and
> forth, or apply a patch and revert it.
>
> Cc: Andy Whitcroft <[email protected]>
> Signed-off-by: Michal Marek <[email protected]>
> ---
> scripts/checkpatch.pl | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 4c0383d..dbcdf04 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2804,6 +2804,11 @@ sub process {
> WARN("__func__ should be used instead of gcc specific __FUNCTION__\n" . $herecurr);
> }
>
> +# check for pointless usage of __TIME__ and friends
> + if ($line =~ /\b__(TIME|DATE|TIMESTAMP)__\b/) {
> + WARN("Usage of __$1__ should be avoided to keep the build deterministic\n" . $herecurr);
> + }
> +
> # check for semaphores initialized locked
> if ($line =~ /^.\s*sema_init.+,\W?0\W?\)/) {
> WARN("consider using a completion\n" . $herecurr);
> --
> 1.7.4.1

Looks reasonable to me.

-apw