This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[PATCH] libtool: Sort output of 'find' to enable deterministic builds.


so that gcc builds in a reproducible way
in spite of indeterministic filesystem readdir order

See https://reproducible-builds.org/ for why this is good.

While working on the reproducible builds effort, I found that
when building the gcc8 package for openSUSE, there were differences
between each build in resulting binaries like gccgo, cc1obj and cpp
because the order of objects in libstdc++.a varied based on
the order of entries returned by the filesystem.

Two remaining issues are with timestamps in the ada build
and with profiledbootstrap that only is reproducible if all inputs
in the profiling run remain constant

Testcases:
  none included because patch is trivial and it would need to compare builds on 2 filesystems.

Bootstrapping and testing:
  tested successfully with gcc8 on x86_64

[gcc]
2018-06-19  Bernhard M. Wiedemann  <bwiedemann@suse.de>

        libtool: Sort output of 'find' to enable deterministic builds.

---
pulled in libtool commit 74c8993c178a1386ea5e2363a01d919738402f30
because a full update appears to be too troublesome after 8+ years
but we still really want that fix.

See also https://gcc.gnu.org/ml/gcc/2017-10/msg00060.html
---
 libtool.m4 | 8 ++++----
 ltmain.sh  | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/libtool.m4 b/libtool.m4
index 24d13f344..940faaa16 100644
--- a/libtool.m4
+++ b/libtool.m4
@@ -6005,20 +6005,20 @@ if test "$_lt_caught_CXX_error" != yes; then
 	      _LT_TAGVAR(prelink_cmds, $1)='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $objs $libobjs $compile_deplibs~
-		compile_command="$compile_command `find $tpldir -name \*.o | $NL2SP`"'
+		compile_command="$compile_command `find $tpldir -name \*.o | sort | $NL2SP`"'
 	      _LT_TAGVAR(old_archive_cmds, $1)='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $oldobjs$old_deplibs~
-		$AR $AR_FLAGS $oldlib$oldobjs$old_deplibs `find $tpldir -name \*.o | $NL2SP`~
+		$AR $AR_FLAGS $oldlib$oldobjs$old_deplibs `find $tpldir -name \*.o | sort | $NL2SP`~
 		$RANLIB $oldlib'
 	      _LT_TAGVAR(archive_cmds, $1)='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $predep_objects $libobjs $deplibs $convenience $postdep_objects~
-		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname -o $lib'
+		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | sort | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname -o $lib'
 	      _LT_TAGVAR(archive_expsym_cmds, $1)='tpldir=Template.dir~
 		rm -rf $tpldir~
 		$CC --prelink_objects --instantiation_dir $tpldir $predep_objects $libobjs $deplibs $convenience $postdep_objects~
-		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname ${wl}-retain-symbols-file ${wl}$export_symbols -o $lib'
+		$CC -shared $pic_flag $predep_objects $libobjs $deplibs `find $tpldir -name \*.o | sort | $NL2SP` $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname ${wl}-retain-symbols-file ${wl}$export_symbols -o $lib'
 	      ;;
 	    *) # Version 6 and above use weak symbols
 	      _LT_TAGVAR(archive_cmds, $1)='$CC -shared $pic_flag $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags ${wl}-soname ${wl}$soname -o $lib'
diff --git a/ltmain.sh b/ltmain.sh
index 9503ec85d..79f9ba89a 100644
--- a/ltmain.sh
+++ b/ltmain.sh
@@ -2917,7 +2917,7 @@ func_extract_archives ()
 	    darwin_file=
 	    darwin_files=
 	    for darwin_file in $darwin_filelist; do
-	      darwin_files=`find unfat-$$ -name $darwin_file -print | $NL2SP`
+	      darwin_files=`find unfat-$$ -name $darwin_file -print | sort | $NL2SP`
 	      $LIPO -create -output "$darwin_file" $darwin_files
 	    done # $darwin_filelist
 	    $RM -rf unfat-$$
@@ -2932,7 +2932,7 @@ func_extract_archives ()
         func_extract_an_archive "$my_xdir" "$my_xabs"
 	;;
       esac
-      my_oldobjs="$my_oldobjs "`find $my_xdir -name \*.$objext -print -o -name \*.lo -print | $NL2SP`
+      my_oldobjs="$my_oldobjs "`find $my_xdir -name \*.$objext -print -o -name \*.lo -print | sort | $NL2SP`
     done
 
     func_extract_archives_result="$my_oldobjs"
-- 
2.13.7


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]