C ABI changes between gcc 2.96 and gcc 3.2?

C ABI changes between gcc 2.96 and gcc 3.2?

[H. J. Lu]

I was investigating an odd crash after modifying mips.c in gcc 3.2.
I built a gcc 3.2 cross compiler on Linux/x86, using gcc 3.2. After
I modified mips.c, I tried to rebuild the cross compiler. I got

./xgcc -B./ -B/export/tools-3.2/mipsel-linux/bin/ -isystem
/export/tools-3.2/mipsel-linux/include -isystem
/export/tools-3.2/mipsel-linux/sys-include -O2 -DIN_GCC -DCROSS_COMPILE   -W
-Wall -Wwrite-strings -Wstrict-prototypes -Wmissing-prototypes -isystem
./include  -I. -I. -I/export/linux/src/tools-3.2/tools/gcc
-I/export/linux/src/tools-3.2/tools/gcc/.
-I/export/linux/src/tools-3.2/tools/gcc/config
-I/export/linux/src/tools-3.2/tools/gcc/../include  -g0
-finhibit-size-directive -fno-inline-functions -fno-exceptions  \
   -c /export/linux/src/tools-3.2/tools/gcc/crtstuff.c -DCRT_BEGIN \
  -o crtbegin.o
/export/linux/src/tools-3.2/tools/gcc/crtstuff.c: In function
`__do_global_dtors_aux':
/export/linux/src/tools-3.2/tools/gcc/crtstuff.c:286: internal error:
Segmentation fault
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://www.gnu.org/software/gcc/bugs.html> for instructions.

It turned out that I recompiled mips.c with gcc 2.96 by accident and 
targetm in mips.c had a different layout from the one compiled with
gcc 3.2. I got

(gdb) p targetm
...
  cannot_modify_jumps_p = 0x1}

instead of

(gdb) p targetm
...
  cannot_modify_jumps_p = 0x8212df0 <hook_void_bool_false>}

Is that a known issue? I guess I can extract a testcase out of it. I
think it may impact people who try to use gcc 2.96 with glibc compiled
with gcc 3.2.


H.J.

Re: C ABI changes between gcc 2.96 and gcc 3.2?

[Joseph S. Myers]

On Mon, 14 Oct 2002, H. J. Lu wrote:

> Is that a known issue? I guess I can extract a testcase out of it. I
> think it may impact people who try to use gcc 2.96 with glibc compiled
> with gcc 3.2.

This would be the broken <stdbool.h> in 2.9x.  An untested patch for that
is at <http://gcc.gnu.org/ml/gcc/2002-09/msg00797.html> (without the
removal of the configure test for <stdbool.h> that should accompany it).  
Unless glibc uses or used <stdbool.h> this is irrelevant to glibc.

-- 
Joseph S. Myers
jsm28@cam.ac.uk

Re: C ABI changes between gcc 2.96 and gcc 3.2?

[H. J. Lu]

On Tue, Oct 15, 2002 at 01:35:55AM +0100, Joseph S. Myers wrote:
> On Mon, 14 Oct 2002, H. J. Lu wrote:
> 
> > Is that a known issue? I guess I can extract a testcase out of it. I
> > think it may impact people who try to use gcc 2.96 with glibc compiled
> > with gcc 3.2.
> 
> This would be the broken <stdbool.h> in 2.9x.  An untested patch for that
> is at <http://gcc.gnu.org/ml/gcc/2002-09/msg00797.html> (without the
> removal of the configure test for <stdbool.h> that should accompany it).  
> Unless glibc uses or used <stdbool.h> this is irrelevant to glibc.

In the current glibc from CVS:

# find -type f | xargs grep stdbool.h
./elf/dl-load.c:#include <stdbool.h>
./elf/rtld.c:#include <stdbool.h>
./iconv/iconv_prog.c:#include <stdbool.h>
./iconvdata/tst-e2big.c:#include <stdbool.h>
./locale/programs/localedef.c:#include <stdbool.h>
./locale/programs/localedef.h:#include <stdbool.h>
./locale/programs/locarchive.c:#include <stdbool.h>
./locale/loadarchive.c:#include <stdbool.h>
./localedata/gen-unicode-ctype.c:#include <stdbool.h>
./malloc/memusage.c:#include <stdbool.h>
./nscd/grpcache.c:#include <stdbool.h>
./nscd/hstcache.c:#include <stdbool.h>
./nscd/pwdcache.c:#include <stdbool.h>
./nss/getXXbyYY_r.c:#include <stdbool.h>
./sysdeps/generic/ldsodefs.h:#include <stdbool.h>
./sysdeps/posix/readv.c:#include <stdbool.h>
./sysdeps/posix/writev.c:#include <stdbool.h>
./sysdeps/pthread/aio_suspend.c:#include <stdbool.h>

Since no header files use <stdbool.h>, I guess it may be ok.


H.J.