devtools: check orphan symbols in map files

The script check-symbol-maps.sh finds the symbols exported
in a map file but not referenced in the codebase.

Suggested-by: Pavan Nikhilesh <pbhagavatula@caviumnetworks.com>
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>

MAINTAINERS

@@ -81,6 +81,7 @@ F: devtools/check-dup-includes.sh
 F: devtools/check-maintainers.sh
 F: devtools/check-git-log.sh
 F: devtools/check-includes.sh
+F: devtools/check-symbol-maps.sh
 F: devtools/checkpatches.sh
 F: devtools/get-maintainer.sh
 F: devtools/git-log-fixes.sh

devtools/check-symbol-maps.sh

@@ -0,0 +1,30 @@
+#! /bin/sh -e
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright 2018 Mellanox Technologies, Ltd
+
+cd $(dirname $0)/..
+
+# speed up by ignoring Unicode details
+export LC_ALL=C
+
+find_orphan_symbols ()
+{
+    for map in $(find lib drivers -name '*.map') ; do
+        for sym in $(sed -rn 's,^([^}]*_.*);,\1,p' $map) ; do
+            if echo $sym | grep -q '^per_lcore_' ; then
+                continue
+            fi
+            if ! grep -q -r --exclude=$(basename $map) \
+                    -w $sym $(dirname $map) ; then
+                echo "$map: $sym"
+            fi
+        done
+    done
+}
+
+orphan_symbols=$(find_orphan_symbols)
+if [ -n "$orphan_symbols" ] ; then
+    echo "Found only in symbol map file:"
+    echo "$orphan_symbols" | sed 's,^,\t,'
+    exit 1
+fi