svn commit: r281811 - head/tools/build

[Bryan Drewery]

Author: bdrewery
Date: Tue Apr 21 03:29:03 2015
New Revision: 281811
URL: https://svnweb.freebsd.org/changeset/base/281811

Log:
  - For executables search for matching (B) global uninitialized BSS symbols from
    linked libraries. Only do this for BSS symbols that have a size which avoids
    __bss_start. Without this some libraries would be considered unneeded even
    though they were providing a B symbol.
  - Add in the symbols from crt1.o to cover a handful of common unresolved symbols.
  - Consider (C) common data symbols as provided by libraries/crt1.
  - Move libkey() function to more appropriate place.
  
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/tools/build/check-links.sh

Modified: head/tools/build/check-links.sh
==============================================================================
--- head/tools/build/check-links.sh	Tue Apr 21 03:06:58 2015	(r281810)
+++ head/tools/build/check-links.sh	Tue Apr 21 03:29:03 2015	(r281811)
@@ -1,6 +1,23 @@
 #!/bin/sh
 # $FreeBSD$
 
+libkey() {
+	libkey="lib_symbols_$1"
+	patterns=[.+,-]
+	replacement=_
+	while :; do
+		case " ${libkey} " in
+			*${patterns}*)
+				libkey="${libkey%%${patterns}*}${replacement}${libkey#*${patterns}}"
+				;;
+			*)
+				break
+				;;
+		esac
+	done
+	return 0
+}
+
 ret=0
 CHECK_UNRESOLVED=1
 while getopts "U" flag; do
@@ -11,33 +28,17 @@ done
 shift $((OPTIND-1))
 
 mime=$(file -L --mime-type $1)
+isbin=0
 case $mime in
-*application/x-executable);;
+*application/x-executable) isbin=1 ;;
 *application/x-sharedlib);;
 *) 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 $1}' | tr '\n' ' ')
+unresolved_symbols=$(nm -D --format=posix "$1" | awk -v isbin=${isbin} '$2 == "U" || ($2 == "B" && $4 != "" && isbin == 1) {print $1}' | tr '\n' ' ')
 ldd_libs=$(ldd $(realpath $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=
 resolved_symbols=
@@ -50,11 +51,11 @@ for lib in $(readelf -d $1 | awk '$2 ~ /
 	done
 	list_libs="$list_libs $lib"
 	foundone=
-	lib_symbols="$(nm -D --defined-only --format=posix "${libpath}" | awk '$2 ~ /R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
+	lib_symbols="$(nm -D --defined-only --format=posix "${libpath}" | awk '$2 ~ /C|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}"
+		setvar "${libkey}" "${lib_symbols}"
 	fi
 	for fct in ${lib_symbols}; do
 		case " ${unresolved_symbols} " in
@@ -70,6 +71,14 @@ for lib in $(readelf -d $1 | awk '$2 ~ /
 done
 
 if [ ${CHECK_UNRESOLVED} -eq 1 ]; then
+	# Add in crt1 symbols
+	list_libs="${list_libs} crt1.o"
+	lib_symbols="$(nm --defined-only --format=posix "/usr/lib/crt1.o" | awk '$2 ~ /C|R|D|T|W|B|V/ {print $1}' | tr '\n' ' ')"
+	# Save the global symbols for this lib
+	libkey "crt1.o"
+	setvar "${libkey}" "${lib_symbols}"
+
+	# No search libs for all symbols and report missing ones.
 	for sym in ${unresolved_symbols}; do
 		found=0
 		for lib in ${list_libs}; do