[PATCH v1 1/1] scripts/tags.sh: Fix gtags generation for O= kernel builds

["Ahmed S. Darwish" <darwi@linutronix.de>]

gtags considers any file outside of its current working directory
"outside the source tree" and refuses to index it.

For O= kernel builds, scripts/tags.sh invokes gtags with the current
working directory set to ${O}. This leads to gtags ignoring the entire
kernel source and generating an empty index.

For O= builds, set gtags' working directory to the kernel source tree
and explicitly set its output path through parameters instead.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
---
 scripts/tags.sh | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/scripts/tags.sh b/scripts/tags.sh
index ea31640b2671..1a6db535503b 100755
--- a/scripts/tags.sh
+++ b/scripts/tags.sh
@@ -131,7 +131,14 @@ docscope()
 
 dogtags()
 {
-	all_target_sources | gtags -i -f -
+	# gtags refuses to index any file outside of the current working
+	# directory. For O= builds, set the current working directory to
+	# the kernel source tree and the output tags dir to ${O}.
+	suffixparams=
+	if [ -v O ]; then
+		suffixparams="-C $tree $O"
+	fi
+	all_target_sources | gtags -i -f - $suffixparams
 }
 
 # Basic regular expressions with an optional /kind-spec/ for ctags and
-- 
2.30.2