script/checkpatch.pl: warn about deprecated use of EXTRA_{A,C,CPP,LD}…

…FLAGS

Usage of these flags has been deprecated for nearly 4 years by:

    commit f77bf01
    Author: Sam Ravnborg <sam@neptun.(none)>
    Date:   Mon Oct 15 22:25:06 2007 +0200

        kbuild: introduce ccflags-y, asflags-y and ldflags-y

Moreover, these flags (at least EXTRA_CFLAGS) have been documented for command
line use. By default, gmake(1) do not override command line setting, so this is
likely to result in build failure or unexpected behavior.

Warn about their introduction in Makefile or Kbuild files.

Cc: Sam Ravnborg <[email protected]>
Cc: Andy Whitcroft <[email protected]>
Signed-off-by: Arnaud Lacombe <[email protected]>
Signed-off-by: Michal Marek <[email protected]>

scripts/checkpatch.pl

@@ -1661,6 +1661,20 @@ sub process {
 			#print "is_end<$is_end> length<$length>\n";
 		}
 
+		if (($realfile =~ /Makefile.*/ || $realfile =~ /Kbuild.*/) &&
+		    ($line =~ /\+(EXTRA_[A-Z]+FLAGS).*/)) {
+			my $flag = $1;
+			my $replacement = {
+				'EXTRA_AFLAGS' =>   'asflags-y',
+				'EXTRA_CFLAGS' =>   'ccflags-y',
+				'EXTRA_CPPFLAGS' => 'cppflags-y',
+				'EXTRA_LDFLAGS' =>  'ldflags-y',
+			};
+
+			WARN("DEPRECATED_VARIABLE",
+			     "Use of $flag is deprecated, please use \`$replacement->{$flag} instead.\n" . $herecurr) if ($replacement->{$flag});
+		}
+
 # check we are in a valid source file if not then ignore this hunk
 		next if ($realfile !~ /\.(h|c|s|S|pl|sh)$/);