[PATCH, GCC/ARM, 2/10] Add command line support for Armv8.1-M Mainline

[PATCH, GCC/ARM, 2/10] Add command line support for Armv8.1-M Mainline

Besides the expected enabling of the new value for the -march
command-line option (-march=armv8.1-m.main) and its extensions (see
below), this patch disables support of the Security Extensions for this
newly added architecture. This is done both by not including the cmse
bit in the architecture description and by throwing an error message
when user request Armv8.1-M Mainline Security Extensions. Note that
Armv8-M Baseline and Mainline Security Extensions are still enabled.

Only extensions for already supported instructions are implemented in
this patch. Other extensions (MVE integer and float) will be added in
separate patches. The following configurations are allowed for Armv8.1-M
Mainline with regards to FPU and implemented in this patch:
+ no FPU (+nofp)
+ single precision VFPv5 with FP16 (+fp)
+ double precision VFPv5 with FP16 (+fp.dp)

ChangeLog entry are as follow:

*** gcc/ChangeLog ***

2020-01-16  Mihail-Calin Ionescu <mihail.ionescu@arm.com>
2020-01-16  Thomas Preud'homme <thomas.preudhomme@arm.com>

	* config/arm/arm-cpus.in (armv8_1m_main): New feature.
	(ARMv4, ARMv4t, ARMv5t, ARMv5te, ARMv5tej, ARMv6, ARMv6j, ARMv6k,
	ARMv6z, ARMv6kz, ARMv6zk, ARMv6t2, ARMv6m, ARMv7, ARMv7a, ARMv7ve,
	ARMv7r, ARMv7m, ARMv7em, ARMv8a, ARMv8_1a, ARMv8_2a, ARMv8_3a,
	ARMv8_4a, ARMv8_5a, ARMv8m_base, ARMv8m_main, ARMv8r): Reindent.
	(ARMv8_1m_main): New feature group.
	(armv8.1-m.main): New architecture.
	* config/arm/arm-tables.opt: Regenerate.
	* config/arm/arm.c (arm_arch8_1m_main): Define and default initialize.
	(arm_option_reconfigure_globals): Initialize arm_arch8_1m_main.
	(arm_options_perform_arch_sanity_checks): Error out when targeting
	Armv8.1-M Mainline Security Extensions.
	* config/arm/arm.h (arm_arch8_1m_main): Declare.

*** gcc/testsuite/ChangeLog ***

2020-01-16  Mihail-Calin Ionescu <mihail.ionescu@arm.com>
2020-01-16  Thomas Preud'homme <thomas.preudhomme@arm.com>

	* lib/target-supports.exp
	(check_effective_target_arm_arch_v8_1m_main_ok): Define.
	(add_options_for_arm_arch_v8_1m_main): Likewise.
	(check_effective_target_arm_arch_v8_1m_main_multilib): Likewise.