[patch, fortran] PR 17758, make abort and exit noreturn

[Tobias Schlüter]

:REVIEWMAIL:

Thomas Koenig wrote:
> 2005-08-12  Thomas Koenig  <Thomas.Koenig@online.de>
> 
> 	PR fortran/17758
> 	* gfortran.h (symbol_attribute):  Add noreturn to the structure.
> 	(gfc_intrinsic_sym):  Add noreturn to the structure.
> 	* intrinsic.c (make_noreturn):  New function.
> 	(add_subroutines):  Mark subroutines abort and exit as noreturn.
> 	(gfc_intrinsic_sub_interface):  Copy noreturn attribute from
> 	isym to the resolved symbol.
> 	* trans-decl.c (gfc_get_extern_function_decl): Set function
> 	as VOLATILE (== noreturn) if the noreturn attribute is set.
> 
> 2005-08-12  Thomas Koenig  <Thomas.Koenig@online.de>
> 
> 	PR fortran/17758
> 	gfortran.dg/nonreturning_statements.f90: New test.

This is ok, given that the next_sym[-1] ugliness is existing practice.

WRT the testcase, it seems safer to scan the assembly for the names of the
bogus functions (i.e. use dg-scan-assembler-not, see
http://gcc.gnu.org/wiki/HowToPrepareATestcase) instead of assuming that the
calls will be removed even at -O0.

- Tobi