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

[Michal Marek]

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 <apw@xxxxxxxxxxxxx>
Signed-off-by: Michal Marek <mmarek@xxxxxxx>
---
 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

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