[ARC] Reimplement exception handling support.

[ARC] Reimplement exception handling support.

2016-06-09  Claudiu Zissulescu  <claziss@synopsys.com>
	    Andrew Burgess  <andrew.burgess@embecosm.com>

	* config/arc/arc-protos.h (arc_compute_frame_size): Delete
	declaration.
	(arc_return_slot_offset): Likewise.
	(arc_eh_return_address_location): New declaration.
	* config/arc/arc.c (TARGET_BUILTIN_SETJMP_FRAME_VALUE): Define.
	(MUST_SAVE_REGISTER): Add exception handler case.
	(MUST_SAVE_RETURN_ADDR): Likewise.
	(arc_frame_pointer_required): Likewise.
	(arc_frame_pointer_needed): New function.
	(arc_compute_frame_size): Changed.
	(arc_expand_prologue): Likewise.
	(arc_expand_epilogue): Likewise.
	(arc_initial_elimination_offset): Likewise.
	(arc_return_slot_offset): Delete.
	(arc_eh_return_address_location): New function.
	(arc_builtin_setjmp_frame_value): Likewise.
	* config/arc/arc.h (EH_RETURN_DATA_REGNO): Use 2 registers.
	(EH_RETURN_STACKADJ_RTX): Define.
	(EH_RETURN_HANDLER_RTX): Likewise.
	* config/arc/arc.md (eh_return): Delete.

Co-Authored-By: Andrew Burgess <andrew.burgess@embecosm.com>
From-SVN: r254997