RFA: try to ensure abort has valid return address
Jim Blandy
jimb@zwingli.cygnus.com
Fri Jan 11 22:45:00 GMT 2002
2002-01-12 Jim Blandy <jimb@redhat.com>
* gdb.base/coremaker.c (func2): Try to arrange for the return
address passed to `abort' to fall within `func2', so we can get
backtraces.
Index: gdb/testsuite/gdb.base/coremaker.c
===================================================================
RCS file: /cvs/cvsfiles/devo/gdb/testsuite/gdb.base/coremaker.c,v
retrieving revision 1.4
diff -c -r1.4 coremaker.c
*** gdb/testsuite/gdb.base/coremaker.c 1999/06/25 23:44:28 1.4
--- gdb/testsuite/gdb.base/coremaker.c 2002/01/12 06:42:09
***************
*** 81,87 ****
}
void
! func2 ()
{
int coremaker_local[5];
int i;
--- 81,87 ----
}
void
! func2 (int please_abort)
{
int coremaker_local[5];
int i;
***************
*** 104,116 ****
for (i = 0; i < 5; i++)
coremaker_bss += coremaker_local[i];
coremaker_data = coremaker_ro + 1;
! abort ();
}
void
func1 ()
{
! func2 ();
}
int main ()
--- 104,138 ----
for (i = 0; i < 5; i++)
coremaker_bss += coremaker_local[i];
coremaker_data = coremaker_ro + 1;
!
! /* This function used to simply call `abort' unconditionally.
! However, because GCC sometimes knows that `abort' will never
! return, the `call' instruction that invokes `abort' would
! sometimes be the very last instruction in this function. The
! epilogue instructions you'd normally expect --- deallocating the
! frame, jumping to the return address --- were omitted, since
! they'd never be reached anyway. This means that the return
! address passed to abort (which it'll never use) actually points
! beyond the end of the caller! Sometimes the return address
! seemed to be in the next function; sometimes it seemed to be in
! padding instructions between functions, for which there was no
! line number info. In any case, GDB had difficulties producing a
! backtrace in this case.
!
! There's no way to force the compiler not to put the call to
! `abort' at the very end of the function --- after all, it is
! functionally correct to do so. But we hope that putting it in a
! conditional will make it more likely that GDB can get a
! backtrace, and find coremaker_local, which is what we really care
! about. */
! if (please_abort)
! abort ();
}
void
func1 ()
{
! func2 (1);
}
int main ()
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