scripts/tags.sh: Resolve gtags empty index generation

commit e1b37563caffc410bb4b55f153ccb14dede66815 upstream.

gtags considers any file outside of its current working directory
"outside the source tree" and refuses to index it. For O= kernel builds,
or when "make" is invoked from a directory other then the kernel source
tree, gtags ignores the entire kernel source and generates an empty
index.

Force-set gtags current working directory to the kernel source tree.

Due to commit 9da0763bdd82 ("kbuild: Use relative path when building in
a subdir of the source tree"), if the kernel build is done in a
sub-directory of the kernel source tree, the kernel Makefile will set
the kernel's $srctree to ".." for shorter compile-time and run-time
warnings. Consequently, the list of files to be indexed will be in the
"../*" form, rendering all such paths invalid once gtags switches to the
kernel source tree as its current working directory.

If gtags indexing is requested and the build directory is not the kernel
source tree, index all files in absolute-path form.

Note, indexing in absolute-path form will not affect the generated
index, as paths in gtags indices are always relative to the gtags "root
directory" anyway (as evidenced by "gtags --dump").

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/scripts/tags.sh b/scripts/tags.sh
index 4e18ae5282a69d222523d3db7a774ab9a5857aca..f667527ddff5c05809a294c4e216d885e47821cb 100755 (executable)
--- a/scripts/tags.sh
+++ b/scripts/tags.sh
@@ -28,6 +28,13 @@ fi
 # ignore userspace tools
 ignore="$ignore ( -path ${tree}tools ) -prune -o"
 
+# gtags(1) refuses to index any file outside of its current working dir.
+# If gtags indexing is requested and the build output directory is not
+# the kernel source tree, index all files in absolute-path form.
+if [[ "$1" == "gtags" && -n "${tree}" ]]; then
+       tree=$(realpath "$tree")/
+fi
+
 # Detect if ALLSOURCE_ARCHS is set. If not, we assume SRCARCH
 if [ "${ALLSOURCE_ARCHS}" = "" ]; then
        ALLSOURCE_ARCHS=${SRCARCH}
@@ -134,7 +141,7 @@ docscope()
 
 dogtags()
 {
-       all_target_sources | gtags -i -f -
+       all_target_sources | gtags -i -C "${tree:-.}" -f - "$PWD"
 }
 
 # Basic regular expressions with an optional /kind-spec/ for ctags and