[binutils][arm] arm support for ARMv8.m Custom Datapath Extension

[binutils][arm] arm support for ARMv8.m Custom Datapath Extension

This patch is part of a series that adds support for the Armv8.m
ARMv8.m Custom Datapath Extension to binutils.

This patch introduces the Custom Instructions Class 1/2/3 (Single/
Dual, Accumulator/Non-accumulator varianats) to the arm backend.

The following Custom Instructions are added: cx1, cx1a,
cx1d, cx1da, cx2, cx2a, cx2d, cx2da, cx3, cx3a, cx3d, cx3da.

Specification can be found at
https://developer.arm.com/docs/ddi0607/latest

This patch distinguishes between enabling CDE for different coprocessor
numbers by defining multiple architecture flags.  This means that the
parsing of the architecture extension flags is kept entirely in the
existing code path.

We introduce a new IT block state to indicate the behaviour of these
instructions.  This new state allows being used in an IT block or
outside an IT block, but does not allow the instruction to be used
inside a VPT block.
We need this since the CX*A instruction versions can be used in IT
blocks, but they aren't to have the conditional suffixes on them.  Hence
we need to mark an instruction as allowed in either position.

We also need a new flag to objdump, in order to determine whether to
disassemble an instruction as CDE related or not.

Successfully regression tested on arm-none-eabi, and arm-wince-pe.

gas/ChangeLog:

2020-02-10  Stam Markianos-Wright  <stam.markianos-wright@arm.com>
	    Matthew Malcomson  <matthew.malcomson@arm.com>

	* config/tc-arm.c (arm_ext_cde*): New feature sets for each
	CDE coprocessor that can be enabled.
	(enum pred_instruction_type): New pred type.
	(BAD_NO_VPT): New error message.
	(BAD_CDE): New error message.
	(BAD_CDE_COPROC): New error message.
	(enum operand_parse_code): Add new immediate operands.
	(parse_operands): Account for new immediate operands.
	(check_cde_operand): New.
	(cde_coproc_enabled): New.
	(cde_coproc_pos): New.
	(cde_handle_coproc): New.
	(cxn_handle_predication): New.
	(do_custom_instruction_1): New.
	(do_custom_instruction_2): New.
	(do_custom_instruction_3): New.
	(do_cx1): New.
	(do_cx1a): New.
	(do_cx1d): New.
	(do_cx1da): New.
	(do_cx2): New.
	(do_cx2a): New.
	(do_cx2d): New.
	(do_cx2da): New.
	(do_cx3): New.
	(do_cx3a): New.
	(do_cx3d): New.
	(do_cx3da): New.
	(handle_pred_state): Define new IT block behaviour.
	(insns): Add newn CX*{,d}{,a} instructions.
	(CDE_EXTENSIONS,armv8m_main_ext_table,armv8_1m_main_ext_table):
	Define new cdecp extension strings.
	* doc/c-arm.texi: Document new cdecp extension arguments.
	* testsuite/gas/arm/cde-scalar.d: New test.
	* testsuite/gas/arm/cde-scalar.s: New test.
	* testsuite/gas/arm/cde-warnings.d: New test.
	* testsuite/gas/arm/cde-warnings.l: New test.
	* testsuite/gas/arm/cde-warnings.s: New test.
	* testsuite/gas/arm/cde.d: New test.
	* testsuite/gas/arm/cde.s: New test.

include/ChangeLog:

2020-02-10  Stam Markianos-Wright  <stam.markianos-wright@arm.com>
	    Matthew Malcomson  <matthew.malcomson@arm.com>

	* opcode/arm.h (ARM_EXT2_CDE): New extension macro.
	(ARM_EXT2_CDE0): New extension macro.
	(ARM_EXT2_CDE1): New extension macro.
	(ARM_EXT2_CDE2): New extension macro.
	(ARM_EXT2_CDE3): New extension macro.
	(ARM_EXT2_CDE4): New extension macro.
	(ARM_EXT2_CDE5): New extension macro.
	(ARM_EXT2_CDE6): New extension macro.
	(ARM_EXT2_CDE7): New extension macro.

opcodes/ChangeLog:

2020-02-10  Stam Markianos-Wright  <stam.markianos-wright@arm.com>
	    Matthew Malcomson  <matthew.malcomson@arm.com>

	* arm-dis.c (struct cdeopcode32): New.
	(CDE_OPCODE): New macro.
	(cde_opcodes): New disassembly table.
	(regnames): New option to table.
	(cde_coprocs): New global variable.
	(print_insn_cde): New
	(print_insn_thumb32): Use print_insn_cde.
	(parse_arm_disassembler_options): Parse coprocN args.