* [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434.
@ 2013-03-07 23:14 Pedro Alves
2013-03-11 18:14 ` Jan Kratochvil
0 siblings, 1 reply; 4+ messages in thread
From: Pedro Alves @ 2013-03-07 23:14 UTC (permalink / raw)
To: gdb-patches
After a chat on IRC, I noticed that my gdb binary was linking with
-Wl,--export-dynamic instead of the better -Wl,--dynamic-list.
Turns out the link/run test that checks for static python has a bug:
configure:11856: checking for the dynamic export flag
configure:11909: gcc -o conftest -g3 -O0 -fno-strict-aliasing -DNDEBUG -fwrapv -static-libstdc++ -static-libgcc -Wl,--dynamic-list=../../src/gdb/proc-service.list conftest.c -ldl -lncurses -lz -lm >&5
/tmp/ccHIJn3p.o: In function `main':
/home/pedro/gdb/mygit/build/gdb/conftest.c:173: undefined reference to `Py_Initialize'
/home/pedro/gdb/mygit/build/gdb/conftest.c:174: undefined reference to `PyRun_SimpleStringFlags'
/home/pedro/gdb/mygit/build/gdb/conftest.c:175: undefined reference to `Py_Finalize'
collect2: error: ld returned 1 exit status
configure:11909: $? = 1
configure: program exited with status 1
configure: failed program was:
... it doesn't actually link with -lpython.
This looks to me to be the correct fix. I now get:
configure:11856: checking for the dynamic export flag
configure:11910: gcc -o conftest -g3 -O0 -fno-strict-aliasing -DNDEBUG -fwrapv -static-libstdc++ -static-libgcc -Wl,--dynamic-list=../../src/gdb/proc-service.list -lpthread -ldl -lutil -lm -lpython2.7 -Xlinker -export-dynamic conftest.c -ldl -lncurses -lz -lm >&5
configure:11910: $? = 0
configure:11910: ./conftest
configure:11910: $? = 0
configure:11929: result: -Wl,--dynamic-list
OK?
gdb/
2013-03-07 Pedro Alves <palves@redhat.com>
* configure: Regenerate.
* configure.ac (check dynamic export flag): Link python test with
$PYTHON_LIBS.
---
gdb/configure | 1 +
gdb/configure.ac | 1 +
2 files changed, 2 insertions(+)
diff --git a/gdb/configure b/gdb/configure
index c54709c..68cd436 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -11888,6 +11888,7 @@ rm -f core conftest.err conftest.$ac_objext \
# Problem does not happen for the recommended libpythonX.Y.so linkage.
old_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS $PYTHON_CFLAGS"
+ LDFLAGS="$LDFLAGS $PYTHON_LIBS"
if test "$cross_compiling" = yes; then :
true
else
diff --git a/gdb/configure.ac b/gdb/configure.ac
index e501766..71c5efb 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1687,6 +1687,7 @@ if test "${gdb_native}" = yes; then
# Problem does not happen for the recommended libpythonX.Y.so linkage.
old_CFLAGS="$CFLAGS"
CFLAGS="$CFLAGS $PYTHON_CFLAGS"
+ LDFLAGS="$LDFLAGS $PYTHON_LIBS"
AC_RUN_IFELSE(
AC_LANG_PROGRAM(
[#include "]${have_libpython}[/Python.h"],
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434.
2013-03-07 23:14 [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434 Pedro Alves
@ 2013-03-11 18:14 ` Jan Kratochvil
2013-03-11 18:35 ` Pedro Alves
0 siblings, 1 reply; 4+ messages in thread
From: Jan Kratochvil @ 2013-03-11 18:14 UTC (permalink / raw)
To: Pedro Alves; +Cc: gdb-patches
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"
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434.
2013-03-11 18:14 ` Jan Kratochvil
@ 2013-03-11 18:35 ` Pedro Alves
2013-03-11 18:52 ` [commit] " Jan Kratochvil
0 siblings, 1 reply; 4+ messages in thread
From: Pedro Alves @ 2013-03-11 18:35 UTC (permalink / raw)
To: Jan Kratochvil; +Cc: gdb-patches
On 03/11/2013 06:14 PM, Jan Kratochvil wrote:
> 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).
Ah yes, LIBS, of course. Please go ahead.
>
> 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
Bummer.
> 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.
Did you try:
- RDYNAMIC='-Wl,--dynamic-list=$(srcdir)/proc-service.list'
+ RDYNAMIC='-Wl,--no-export-dynamic -Wl,--dynamic-list=$(srcdir)/proc-service.list'
?
--
Pedro Alves
^ permalink raw reply [flat|nested] 4+ messages in thread
* [commit] [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434.
2013-03-11 18:35 ` Pedro Alves
@ 2013-03-11 18:52 ` Jan Kratochvil
0 siblings, 0 replies; 4+ messages in thread
From: Jan Kratochvil @ 2013-03-11 18:52 UTC (permalink / raw)
To: Pedro Alves; +Cc: gdb-patches
On Mon, 11 Mar 2013 19:35:33 +0100, Pedro Alves wrote:
> Ah yes, LIBS, of course. Please go ahead.
Checked in:
http://sourceware.org/ml/gdb-cvs/2013-03/msg00095.html
> > ../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
>
> Bummer.
>
> > 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.
>
> Did you try:
>
> - RDYNAMIC='-Wl,--dynamic-list=$(srcdir)/proc-service.list'
> + RDYNAMIC='-Wl,--no-export-dynamic -Wl,--dynamic-list=$(srcdir)/proc-service.list'
>
> ?
I did not try as that would break the Python's intention of LINKFORSHARED's
-export-dynamic. While I hope -fvisibility=hidden would not break it as it
applies only to cc1 and not ld.
This is all sure primarily a Python bug breaking any app it links with it,
this discussion is just about how to workaround it when they were unable to
fix it in 2.5 years:
http://bugs.python.org/issue10112
Jan
^ permalink raw reply [flat|nested] 4+ messages in thread
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2013-03-07 23:14 [RFA PATCH] Fix --dynamic-list test's workaround for http://bugs.python.org/issue4434 Pedro Alves
2013-03-11 18:14 ` Jan Kratochvil
2013-03-11 18:35 ` Pedro Alves
2013-03-11 18:52 ` [commit] " Jan Kratochvil
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