LLDB/NetBSD - Status February 2018

I've managed to unbreak the LLDB debugger as much as possible with the
current kernel and hit problems with ptrace(2) that are causing issues
with further work on proper NetBSD support. Meanwhile, I've upstreamed
all the planned NetBSD patches to sanitizers and helped other BSDs to
gain better or initial support.


Plan for the next milestone

With the approaching NetBSD 8.0 release I plan to finish backporting a
few changes there from HEAD:

- Remove one unused feature from ptrace(2), PT_SET_SIGMASK &
PT_GET_SIGMASK. I've originally introduced these operations with
criu/rr-like software in mind, but they are misusing or even abusing
ptrace(2) and are not regular process debuggers. I plan to remove this
operation from HEAD and backport this to NetBSD-8(BETA), before the
release, so no compat will be required for this call. Future ports of
criu/rr should involve dedicated kernel support for such requirements.
- Finish the backport of _UC_MACHINE_FP() to NetBSD-8. This will allow
use of the same code in sanitizers in HEAD and NetBSD-8.0.
- By popular demand, improve the regnsub(3) and regasub(3) API, adding
support for more or less substitutions than 10.

Once done, I will return to ptrace(2) debugging and corrections.