Add assembler support for ARMv8-M Baseline

Add assembler support for ARMv8-M Baseline

2015-12-24  Thomas Preud'homme  <thomas.preudhomme@arm.com>

bfd/
    (tag_cpu_arch_combine): Adjust comment in v4t_plus_v6_m with regards
    to merging with ARMv8-M Baseline.

binutils/
    * readelf.c (arm_attr_tag_CPU_arch): Add ARMv8-M Baseline Tag_CPU_arch
    value.

gas/
    * config/tc-arm.c (arm_ext_v6t2_v8m): New feature for instructions
    shared between ARMv6T2 and ARMv8-M.
    (move_or_literal_pool): Check mov.w/mvn and movw availability against
    arm_ext_v6t2 and arm_ext_v6t2_v8m respectively instead of checking
    arm_arch_t2.
    (do_t_branch): Error out for wide conditional branch instructions if
    targetting ARMv8-M Baseline.
    (non_v6t2_wide_only_insn): Add the logic for new wide-only instructions
    in ARMv8-M Baseline.
    (wide_insn_ok): New function.
    (md_assemble): Use wide_insn_ok instead of non_v6t2_wide_only_insn and
    adapt error message for unsupported wide instruction to ARMv8-M
    Baseline.
    (insns): Reorganize instructions shared by ARMv8-M Baseline and
    ARMv6t2 architecture.
    (arm_cpus): Set feature bit ARM_EXT2_V6T2_V8M for marvell-pj4 and
    marvell-whitney cores.
    (arm_archs): Define armv8-m.base architecture.
    (cpu_arch_ver): Define ARM_ARCH_V8M_BASE architecture version.
    (aeabi_set_public_attributes): Add logic to set Tag_CPU_arch to 17 for
    ARMv8-M Mainline.  Set Tag_DIV_use for ARMv8-M Baseline as well.

gas/testsuite/
    * gas/arm/archv8m-base.d: New file.
    * gas/arm/attr-march-armv8m.base.d: Likewise.
    * gas/arm/armv8m.base-idiv.d: Likewise.
    * gas/arm/any-armv8m.d: Adapt to deal with ARMv8-M Baseline.

include/elf/
    * arm.h (TAG_CPU_ARCH_V8M_BASE): Declare.

include/opcode/
    * arm.h (ARM_EXT2_V6T2_V8M): New extension bit.
    (ARM_AEXT2_V8A): New architecture extension bitfield.
    (ARM_AEXT2_V8_1A): Use ARM_AEXT2_V8A instead of ARM_EXT2_ATOMICS.
    (ARM_AEXT_V8M_BASE): New architecture extension bitfield.
    (ARM_AEXT2_V8M): Add extension bit ARM_EXT2_V6T2_V8M.
    (ARM_ARCH_V6T2): Use ARM_EXT2_V6T2_V8M for the second extension
    bitfield.
    (ARM_ARCH_V6KT2): Likewise.
    (ARM_ARCH_V6ZT2): Likewise.
    (ARM_ARCH_V6KZT2): Likewise.
    (ARM_ARCH_V7): Likewise.
    (ARM_ARCH_V7A): Likewise.
    (ARM_ARCH_V7VE): Likewise.
    (ARM_ARCH_V7R): Likewise.
    (ARM_ARCH_V7M): Likewise.
    (ARM_ARCH_V7EM): Likewise.
    (ARM_ARCH_V8A): Likewise.
    (ARM_ARCH_V8M_BASE): New architecture bitfield.
    (ARM_ARCH_THUMB2): Include instructions shared by ARMv6t2 and ARMv8-M.
    (ARM_ARCH_V7A_SEC): Use ARM_EXT2_V6T2_V8M for the second extension
    bitfield and reindent.
    (ARM_ARCH_V7A_MP_SEC): Likewise.
    (ARM_ARCH_V7R_IDIV): Likewise.
    (ARM_ARCH_V8A_FP): Use ARM_AEXT2_V8A instead of ARM_EXT2_ATOMICS.
    (ARM_ARCH_V8A_SIMD): Likewise.
    (ARM_ARCH_V8A_CRYPTOV1): Likewise.

opcodes/
    * arm-dis.c (arm_opcodes): Guard movw, movt cbz, cbnz, clrex, ldrex,
    ldrexb, ldrexh, strex, strexb, strexh shared by ARMv6T2 and ARMv8-M by
    ARM_EXT2_V6T2_V8M instead of ARM_EXT_V6T2.