Add support for ARMv8-M Mainline with DSP extension

2016-05-10  Thomas Preud'homme  <thomas.preudhomme@arm.com>

bfd/
	(elf32_arm_merge_eabi_attributes): Add merging logic for
	Tag_DSP_extension.

binutils/
	* readelf.c (display_arm_attribute): Add output for Tag_DSP_extension.
	(arm_attr_public_tags): Define DSP_extension attribute.

gas/
	* NEWS: Document ARMv8-M and ARMv8-M Security and DSP Extensions.
	* config/tc-arm.c (arm_ext_dsp): New feature for Thumb DSP
	instructions.
	(arm_extensions): Add dsp extension for ARMv8-M Mainline.
	(aeabi_set_public_attributes): Memorize the feature bits of the
	architecture selected for Tag_CPU_arch.  Use it to set
	Tag_DSP_extension to 1 for ARMv8-M Mainline with DSP extension.
	(arm_convert_symbolic_attribute): Define Tag_DSP_extension.
	* testsuite/gas/arm/arch7em-bad.d: Rename to ...
	* testsuite/gas/arm/arch7em-bad-1.d: This.
	* testsuite/gas/arm/arch7em-bad-2.d: New file.
	* testsuite/gas/arm/arch7em-bad-3.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-1.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-2.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-3.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-4.d: Likewise.
	* testsuite/gas/arm/archv8m-main-dsp-5.d: Likewise.
	* testsuite/gas/arm/attr-march-armv8m.main.dsp.d: Likewise.

include/
	* elf/arm.h (Tag_DSP_extension): Define.

ld/
	* testsuite/ld-arm/arm-elf.exp (EABI attribute merging 10 (DSP)): New
	test.
	* testsuite/ld-arm/attr-merge-10b-dsp.s: New file.
	* testsuite/ld-arm/attr-merge-10-dsp.attr: Likewise.