Hi there,

If target mode isn't specified via either gcc configuration option
--with-mode or command line, this patch intends to improve gcc driver to
automatically add option -mthumb for thumb-only target. Tested with gcc
regression test for various arm targets, no regression. Is it OK?

BR,
Terry

gcc/ChangeLog:

2015-03-02  Terry Guo  <terry.guo@arm.com>

        * common/config/arm/arm-common.c (arm_is_target_thumb_only): New
function.
        * config/arm/arm-protos.h (FL_ Macros): Move to ...
        * config/arm/arm-opts.h (FL_ Macros): ... here.
        (struct arm_arch_core_flag): New struct.
        (arm_arch_core_flags): New array for arch/core and flag map.
        * config/arm/arm.h (MODE_SET_SPEC_FUNCTIONS): Define new SPEC
function.
        (EXTRA_SPEC_FUNCTIONS): Include new SPEC function.
        (MODE_SET_SPECS): New SPEC.
        (DRIVER_SELF_SPECS): Include new SPEC.