From 3844bbe29e64c48119ae82f0d1ece2205513e442 Mon Sep 17 00:00:00 2001
From: Bryan Drewery <bdrewery@FreeBSD.org>
Date: Mon, 20 Apr 2015 20:51:19 +0000
Subject: [PATCH] - Speedup significantly by not using subshells for data
 already fetched.   Ran against /usr/local/sbin/pkg:    Before:  25.12 real   
     12.41 user        33.14 sys    After:   0.53 real         0.49 user      
   0.13 sys - Exit with 1 if any missing or unresolved symbol is detected. -
 Add option '-U' to skip looking up unresolved symbols. - Don't consider
 provided weak objects as unresolved (nm V).

Sponsored by:	EMC / Isilon Storage Division
---
 tools/build/check-links.sh | 87 ++++++++++++++++++++++++++++++--------
 1 file changed, 70 insertions(+), 17 deletions(-)

diff --git a/tools/build/check-links.sh b/tools/build/check-links.sh
index 167d76e202ba..781e1d35396c 100755
--- a/tools/build/check-links.sh
+++ b/tools/build/check-links.sh
@@ -1,6 +1,15 @@
 #!/bin/sh
 # $FreeBSD$
 
+ret=0
+CHECK_UNRESOLVED=1
+while getopts "U" flag; do
+	case "${flag}" in
+		U) CHECK_UNRESOLVED=0 ;;
+	esac
+done
+shift $((OPTIND-1))
+
 mime=$(file -L --mime-type $1)
 case $mime in
 *application/x-executable);;
@@ -8,30 +17,74 @@ case $mime in
 *) echo "Not an elf file" >&2 ; exit 1;;
 esac
 
+# Gather all symbols from the target
+unresolved_symbols=$(nm -D -u --format=posix "$1" | awk '$2 == "U" {print $1}' | tr '\n' ' ')
+ldd_libs=$(ldd $1 | awk '{print $1 ":" $3}')
+
+libkey() {
+	libkey="lib_symbols_$1"
+	patterns=[.+,-]
+	replacement=_
+	while :; do
+		case " ${libkey} " in
+			*${patterns}*)
+				libkey="${libkey%%${patterns}*}${replacement}${libkey#*${patterns}}"
+				;;
+			*)
+				break
+				;;
+		esac
+	done
+	return 0
+}
+
 # Check for useful libs
-list_libs=""
+list_libs=
+resolved_symbols=
 for lib in $(readelf -d $1 | awk '$2 ~ /\(?NEEDED\)?/ { sub(/\[/,"",$NF); sub(/\]/,"",$NF); print $NF }'); do
 	echo -n "checking if $lib is needed: "
-	libpath=$(ldd $1 | awk -v lib=$lib '$1 == lib { print $3 }')
-	list_libs="$list_libs $libpath"
-	foundone=0
-	for fct in $(nm -D $libpath | awk '$2 == "R" || $2 == "D" || $2 == "T" || $2 == "W" || $2 == "B" { print $3 }'); do
-		nm -D $1 | awk -v s=$fct '$1 == "U" && $2 == s { found=1 ; exit } END { if (found != 1) { exit 1 } }' && foundone=1 && break
+	for libpair in ${ldd_libs}; do
+		case "${libpair}" in
+			${lib}:*) libpath="${libpair#*:}" && break ;;
+		esac
 	done
-	if [ $foundone -eq 1 ]; then
-		echo -n "yes... "
-		nm -D $1 | awk -v s=$fct '$1 == "U" && $2 == s { print $2 ; exit }'
+	list_libs="$list_libs $lib"
+	foundone=
+	lib_symbols="$(nm -D --defined-only --format=posix "${libpath}" | awk '$2 ~ /R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
+	if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
+		# Save the global symbols for this lib
+		libkey "${lib}"
+		setvar "${libkey}"  "${lib_symbols}"
+	fi
+	for fct in ${lib_symbols}; do
+		case " ${unresolved_symbols} " in
+			*\ ${fct}\ *) foundone="${fct}" && break ;;
+		esac
+	done
+	if [ -n "${foundone}" ]; then
+		echo "yes... ${foundone}"
 	else
 		echo "no"
+		ret=1
 	fi
 done
 
-for sym in $(nm -D $1 | awk '$1 == "U" { print $2 }'); do
-	found=0
-	for l in ${list_libs} ; do
-		nm -D $l | awk -v s=$sym '($2 == "R" || $2 == "D" || $2 == "T" || $2 == "W" || $2 == "B") && $3 == s { found=1 ; exit } END { if (found != 1) { exit 1 } }' && found=1 && break
+if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
+	for sym in ${unresolved_symbols}; do
+		found=0
+		for lib in ${list_libs}; do
+			libkey "${lib}"
+			eval "lib_symbols=\"\${${libkey}}\""
+			# lib_symbols now contains symbols for the lib.
+			case " ${lib_symbols} " in
+				*\ ${sym}\ *) found=1 && break ;;
+			esac
+		done
+		if [ $found -eq 0 ]; then
+			echo "Unresolved symbol $sym"
+			ret=1
+		fi
 	done
-	if [ $found -eq 0 ]; then
-		echo "Unresolved symbol $sym"
-	fi
-done
+fi
+
+exit ${ret}