Re: Ping^2: [Patch] PR 37454 - Fix -rdynamic check in gcc/configure

[Richard Guenther <richard dot guenther at gmail dot com>]

On Fri, Jan 8, 2010 at 10:45 PM, Steve Ellcey <sje@cup.hp.com> wrote:
> On Tue, 2010-01-05 at 16:04 -0500, DJ Delorie wrote:
>> I think this is OK, my only concern is that plugins will now only be
>> enabled for targets where "objdump -T" works.
>
> It should be easy to address this issue by extending the checking in
> configure.ac if and when it becomes necessary. ?Right now I am not aware
> of any targets that support plugins but don't support 'objdump -T'.
>
> I will go ahead and check in my patch.

This seems to break at least my existing trees like

gcc  -g -DIN_GCC   -W -Wall -Wwrite-strings -Wcast-qual
-Wstrict-prototypes -Wmissing-prototypes -Wmissing-format-attribute
-pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings
-Wold-style-definition -Wc++-compat -fno-common  -DHAVE_CONFIG_H -fPIC
-shared -o cc1-dummy c-lang.o stub-objc.o attribs.o c-errors.o c-lex.o
c-pragma.o c-decl.o c-typeck.o c-convert.o c-aux-info.o c-common.o
c-opts.o c-format.o c-semantics.o c-ppoutput.o c-cppbuiltin.o
c-objc-common.o c-dump.o c-pch.o c-parser.o i386-c.o c-gimplify.o
tree-mudflap.o c-pretty-print.o c-omp.o \
          dummy-checksum.o main.o tree-browser.o libbackend.a
../libcpp/libcpp.a ../libdecnumber/libdecnumber.a -ldl
../libcpp/libcpp.a   ../libiberty/libiberty.a
../libdecnumber/libdecnumber.a  -lcloog  -lppl_c -lppl -lgmpxx -lmpc
-lmpfr -lgmp -rdynamic -ldl  -L../zlib -lz -lelf
/usr/lib64/gcc/x86_64-suse-linux/4.3/../../../../x86_64-suse-linux/bin/ld:
c-lang.o: relocation R_X86_64_32 against `.text' can not be used when
making a shared object; recompile with -fPIC
c-lang.o: could not read symbols: Bad value
collect2: ld returned 1 exit status
make: *** [cc1-dummy] Error 1

(non-bootstrapped x86_64-linux).  Non-bootstrapped i?86 simply segfaults.

We certainly do not want to build GCC with -fPIC.

Appearantly there is still LDFLAGS setting where you removed the
save/restore parts:

pluginlibs=
if test x"$enable_plugin" = x"yes"; then

...
  # Check that we can build shared objects with -fPIC -shared
  LDFLAGS="$LDFLAGS -fPIC -shared"
  AC_MSG_CHECKING([for -fPIC -shared])
...
fi

Richard.