Re: wrong postdep_objects for CXX when using "-flto -fuse-linker-plugin"

[Brice De Bruyne]

Hi,

It seems the postdep_objects are set wrong when CXXFLAGS contains 
"-fuse-linker-plugin".
CFLAGS don't matter it seems...


Following patch to libltdl/m4/libtool.m4 and then running ./bootstrap 
fixes this problem:


--- libtool-2.4.1a/libltdl/m4/libtool.m4        2010-11-16 
11:10:09.000000000 +0100
+++ libtool-2.4.1a-1/libltdl/m4/libtool.m4      2010-12-04 
16:07:53.628086809 +0100
@@ -6900,9 +6900,16 @@
 ])

 _lt_libdeps_save_CFLAGS=$CFLAGS
+_lt_libdeps_save_CXXFLAGS=$CXXFLAGS
 case "$CC $CFLAGS " in #(
 *\ -flto*\ *) CFLAGS="$CFLAGS -fno-lto" ;;
 *\ -fwhopr*\ *) CFLAGS="$CFLAGS -fno-whopr" ;;
+*\ -fuse-linker-plugin*\ *) CFLAGS="$CFLAGS -fno-use-linker-plugin" ;;
+esac
+case "$CC $CXXFLAGS " in #(
+*\ -flto*\ *) CXXFLAGS="$CXXFLAGS -fno-lto" ;;
+*\ -fwhopr*\ *) CXXFLAGS="$CXXFLAGS -fno-whopr" ;;
+*\ -fuse-linker-plugin*\ *) CXXFLAGS="$CXXFLAGS -fno-use-linker-plugin" ;;
 esac

 dnl Parse the compiler output and extract the necessary
@@ -7000,6 +7007,7 @@

 $RM -f confest.$objext
 CFLAGS=$_lt_libdeps_save_CFLAGS
+CXXFLAGS=$_lt_libdeps_save_CXXFLAGS

 # PORTME: override above test on systems where it is broken
 m4_if([$1], [CXX],




On 04-12-10 15:40, Brice De Bruyne wrote:
> Hi,
>
> The configure-script seems to misconfigure the postdep_objects_CXX 
> when CFLAGS contains "-flto -fuse-linker-plugin" (using 
> binutils-2.21.51.0.1 and gcc-4.6-20101127):
>
> eg (libtool-2.4.1a):
> CFLAGS="-flto -fuse-linker-plugin" CXXFLAGS="-flto 
> -fuse-linker-plugin" ./configure && grep postdep_objects libtool
>
> postdep_objects="/usr/lib/gcc/i686-pc-linux-gnu/4.6.0/crtendS.o 
> /usr/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../crtn.o 
> /usr/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../crti.o 
> /usr/lib/gcc/i686-pc-linux-gnu/4.6.0/crtbeginS.o 
> /usr/lib/gcc/i686-pc-linux-gnu/4.6.0/crtendS.o 
> /usr/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../crtn.o"
>
> instead of:
>
> postdep_objects="/usr/lib/gcc/i686-pc-linux-gnu/4.6.0/crtendS.o 
> /usr/lib/gcc/i686-pc-linux-gnu/4.6.0/../../../crtn.o"
>
> This does not happen when only -flto or only -fuse-linker-plugin is in 
> CFLAGS, it only happens when they are both in CFLAGS...
>
> I suppose the error comes from the check in libtool.m4....
>
>
> Thanks for looking in to this!
>
> Brice

libtool-2.4.1a-linker_plugin.patch
Description: Text document