Turn FUNCTION_ARG_OFFSET into a hook

[Jeff Law]

On 09/13/2017 01:22 PM, Richard Sandiford wrote:
> Nice and easy, one definition and one use :-)
> 
> Tested on aarch64-linux-gnu, x86_64-linux-gnu and powerpc64le-linux-gnu.
> Also tested by comparing the testsuite assembly output on at least one
> target per CPU directory.  OK to install?
> 
> Richard
> 
> 
> 2017-09-13  Richard Sandiford  <richard.sandiford@linaro.org>
> 	    Alan Hayward  <alan.hayward@arm.com>
> 	    David Sherwood  <david.sherwood@arm.com>
> 
> gcc/
> 	* target.def (function_arg_offset): New hook.
> 	* targhooks.h (default_function_arg_offset): Declare.
> 	* targhooks.c (default_function_arg_offset): New function.
> 	* function.c (locate_and_pad_parm): Use
> 	targetm.calls.function_arg_offset instead of FUNCTION_ARG_OFFSET.
> 	* doc/tm.texi.in (FUNCTION_ARG_OFFSET): Replace with...
> 	(TARGET_FUNCTION_ARG_OFFSET): ...this.
> 	* doc/tm.texi: Regenerate.
> 	* config/spu/spu.h (FUNCTION_ARG_OFFSET): Delete.
> 	* config/spu/spu.c (spu_function_arg_offset): New function.
> 	(TARGET_FUNCTION_ARG_OFFSET): Redefine.
> 	* system.h (FUNCTION_ARG_OFFSET): Poison.
OK.
jeff