On Tue, Oct 31, 2017 at 2:35 PM, Simon Marchi
<simon.marchi@ericsson.com> wrote:
On 2017-10-27 05:31 AM, Yao Qi wrote:
The address space is useless to readonly regcache, so this patch
removes
the parameter to construct readonly regcache.
Can you expand on why the aspace is useless for readonly regcaches?
The
comment of m_aspace says:
/* The address space of this register cache (for registers where it
makes sense, like PC or SP). */
This comment was there because address_space was added for read-write
regcache. Nowadays, address_space in regcache is used for various
breakpoint/watchpoint checkings, and these regcache are not read-only
regcache.
Additionally, regcache itself doesn't use address_space at all, so
various
breakpoint/watchpoint checking code should get address_space from
thread
ptid rather than regcache.
Registers like PC or SP are present even in a readonly regcache, so I
would think that it makes sense to have the address space there as
well.
So, is it that it's really useless (as in it doesn't make sense to
have
it there) or that we just don't happen to use the address space right
now
with readonly regcaches?
It doesn't make sense to have address_space in read-only regcache, at
least. Since we don't have a type/class for read-only regcache, we
still
have to keep address_space in regcache. However, I don't see how
address_space can be used by regcache, we can remove it from regcache
completely, but that is a separate thing.