Re: [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434.

[Jan Kratochvil <jan.kratochvil@redhat.com>]

On Fri, 08 Mar 2013 00:14:00 +0100, Pedro Alves wrote:
> After a chat on IRC, I noticed that my gdb binary was linking with
> -Wl,--export-dynamic instead of the better -Wl,--dynamic-list.

I agree with this fix (with the bit LDFLAGS -> LIBS).

But in practice it does not change anything as the full linking commandline
also contains
	LINKFORSHARED=-Xlinker -export-dynamic
from
	/usr/lib/python2.7/config/Makefile
which overrides it:
	../readline/libreadline.a ../opcodes/libopcodes.a ../bfd/libbfd.a  ../libiberty/libiberty.a ../libdecnumber/libdecnumber.a    -ldl -ldl -lncurses -lz -lm    -lpthread -ldl -lutil -lm -lpython2.7 -Xlinker -export-dynamic -lexpat -llzma ../libiberty/libiberty.a  build-gnulib/import/libgnu.a -ldl -Wl,--dynamic-list=./proc-service.list

The real fix to reduce the stripped GDB binary by 1MB of .dynsym back again
after it was regressed by Python would be to drop gdb/proc-service.list, add
gcc parameter -fvisibility=hidden and mark all the exported symbols (currently
in gdb/proc-service.list) by __attribute__ ((visibility ("default"))).

At least I hope that -fvisibility=hidden won't break Python on the other hand.


Thanks,
Jan


gdb/
2013-03-11  Pedro Alves  <palves@redhat.com>
	    Jan Kratochvil  <jan.kratochvil@redhat.com>

	* configure: Regenerate.
	* configure.ac (check dynamic export flag): Link python test with
	$PYTHON_LIBS.

diff --git a/gdb/configure.ac b/gdb/configure.ac
index e501766..c17f587 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1687,6 +1687,8 @@ if test "${gdb_native}" = yes; then
      # Problem does not happen for the recommended libpythonX.Y.so linkage.
      old_CFLAGS="$CFLAGS"
      CFLAGS="$CFLAGS $PYTHON_CFLAGS"
+     old_LIBS="$LIBS"
+     LIBS="$LIBS $PYTHON_LIBS"
      AC_RUN_IFELSE(
        AC_LANG_PROGRAM(
          [#include "]${have_libpython}[/Python.h"],
@@ -1696,6 +1698,7 @@ if test "${gdb_native}" = yes; then
           Py_Finalize ();
           return err == 0 ? 0 : 1;]),
        [dynamic_list=true], [], [true])
+     LIBS="$old_LIBS"
      CFLAGS="$old_CFLAGS"
    fi
    LDFLAGS="$old_LDFLAGS"