New gdbarch memory tagging hooks

New gdbarch memory tagging hooks

We need some new gdbarch hooks to help us manipulate memory tags without having
to have GDB calls the target methods directly.

This patch adds the following hooks:

gdbarch_memtag_to_string
--
Returns a printable string corresponding to the tag.

gdbarch_tagged_address_p
--
Checks if a particular address is protected with memory tagging.

gdbarch_memtag_mismatch_p
--
Checks if there is a mismatch between the logical tag of a pointer and the
allocation tag.

gdbarch_set_memtags:
--
Sets either the allocation tag or the logical tag for a particular value.

gdbarch_get_memtag:
--
Gets either the allocation tag or the logical tag for a particular value.

gdbarch_granule_size
--
Sets the memory tag granule size, which represents the number of bytes a
particular allocation tag covers. For example, this is 16 bytes for
AArch64's MTE.

I've used struct value as opposed to straight CORE_ADDR so other architectures
can use the infrastructure without having to rely on fixed types.

gdb/ChangeLog:

YYYY-MM-DD  Luis Machado  <luis.machado@linaro.org>

	* arch-utils.c (default_memtag_to_string, +default_tagged_address_p)
	(default_memtag_mismatch_p, default_set_memtags)
	(default_get_memtag): New functions.
	* arch-utils.h (default_memtag_to_string, default_tagged_address_p)
	(default_memtag_mismatch_p, default_set_memtags)
	(default_get_memtag): New prototypes.
	* gdbarch.c: Regenerate.
	* gdbarch.h: Regenerate.
	* gdbarch.sh (memtag_to_string, tagged_address_p, memtag_mismatch_p)
	(set_memtags, get_memtag, memtag_granule_size): New gdbarch hooks.
	(enum memtag_type): New enum.