Hi!
There seem to be a longstanding complaint that libtool is using
-nostdlib when it links libraries using g++. It interferes with
-pthread and I think I have also seen other issues. No one can
give a satisfactory explanation why libtool does this, it seems
like it is just the way it has always been and noone dares
changing it. To me, it all smells like something that was needed
once upon a time when g++ was still immature, and whatever issues
it solved we no longer need to worry about. So, just for thrills
I had a quick peek at the code, and it looks quite simple to
simply nix this obnoxious -nostdlib use.
I realize that the timing isn't the best with the alpha release
and all, but this probably needs to be tested a bit more before
it's pushed anyway, so I'm simply posting this as an RFC and
don't expect it to be committed until later.
Should it be listed as an incompatible change? Or simply a bug
fix?
BTW, it even appears to work, but please test, as I have only
done very light testing...
Oh well. Any thoughts?
Cheers,
Peter
>From a233b4562d4274053852bc0353e36931beeb4803 Mon Sep 17 00:00:00 2001
From: Peter Rosin
Date: Fri, 8 Nov 2013 19:01:24 +0100
Subject: [PATCH] libtool: Do not use -nostdlib when linking with g++.
Fixes part of bug#15646 and Debian bug 468555.
* m4/libtool.m4 (_LT_LANG_CXX_CONFIG) [g++]
: Drop -nostdlib, $predep_objects and
$postdep_objects.
* NEWS: Update.
---
NEWS |6 ++
m4/libtool.m4 | 30 +++---
2 files changed, 21 insertions(+), 15 deletions(-)
diff --git a/NEWS b/NEWS
index 0c85812..5717385 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,12 @@ NEWS - list of user-visible changes between releases of GNU Libtool
* Noteworthy changes in release ?.? (-??-??) [?]
+** Important incompatible changes:
+
+ - When linking shared libraries with g++, trust the compiler driver to
+interface correctly with the linker. I.e., drop the -nostdlib
+option in this case. Fixes point 2 (and perhaps 3) in bug#15646, as
+well as Debian bug 468555.
* Noteworthy changes in release 2.4.2.418 (2013-10-27) [alpha]
diff --git a/m4/libtool.m4 b/m4/libtool.m4
index 4bc6b22..d13afc3 100644
--- a/m4/libtool.m4
+++ b/m4/libtool.m4
@@ -6046,8 +6046,8 @@ if test yes != "$_lt_caught_CXX_error"; then
# Check if GNU C++ uses GNU ld as the underlying linker, since the
# archiving commands below assume that GNU ld is being used.
if test yes = "$with_gnu_ld"; then
-_LT_TAGVAR(archive_cmds, $1)='$CC $pic_flag -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname -o $lib'
-_LT_TAGVAR(archive_expsym_cmds, $1)='$CC $pic_flag -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
+_LT_TAGVAR(archive_cmds, $1)='$CC $pic_flag -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname -o $lib'
+_LT_TAGVAR(archive_expsym_cmds, $1)='$CC $pic_flag -shared $libobjs $deplibs $compiler_flags $wl-soname $wl$soname $wl-retain-symbols-file $wl$export_symbols -o $lib'
_LT_TAGVAR(hardcode_libdir_flag_spec, $1)='$wl-rpath $wl$libdir'
_LT_TAGVAR(export_dynamic_flag_spec, $1)='$wl--export-dynamic'
@@ -6073,7 +6073,7 @@ if test yes != "$_lt_caught_CXX_error"; then
# linker, instead of GNU ld. If possible, this setting should
# overridden to take advantage of the native linker features on
# the platform it is being used on.
-_LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -o $lib'
+_LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags -o $lib'
fi
# Commands to make compiler produce verbose output that lists
@@ -6296,7 +6296,7 @@ if test yes != "$_lt_caught_CXX_error"; then
_LT_TAGVAR(enable_shared_with_static_runtimes, $1)=yes
if $LD --help 2>&1 | $GREP 'auto-import' > /dev/null; then
- _LT_TAGVAR(archive_cmds, $1)='$CC -shared -nostdlib $predep_objects $libobjs $deplibs $postdep_objects $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
+ _LT_TAGVAR(archive_cmds, $1)='$CC -shared $libobjs $deplibs $compiler_flags -o $output_objdir/$soname $wl--enable-auto-image-base -Xlinker --out-implib -Xlinker $lib'
# If the export-symbols file already is a .def file, use it as
# is; otherwise, prepend EXPORTS...
_LT_TAGVAR(archive_expsym_cmds, $1)='if _LT_DLL_DEF_P([$export_symbols]); then
@@ -6305,7 +6305,7 @@ if test yes != "$_lt_caught_CXX_error"; then
echo EXPORTS > $output_objdir/$soname.def;
cat $export_symbols >> $output_objdir/$soname.def;
fi~
-$CC -shared -nostdlib $output_objdir/$soname.def $predep_objects $libobjs $deplibs $postdep_objects $comp
