Lots going on here.
This moves OS thread object lifetime management and internal thread
state lifetime management to the frontend. This causes a bunch of thread
handling to move from the FEXCore Context to the frontend.
Looking at `FEXCore/include/FEXCore/Core/Context.h` really shows how
much of the API has moved to the frontend that FEXCore no longer needs
to manage. Primarily this makes FEXCore itself no longer need to care
about most of the management of the emulation state.
A large amount of the behaviour moved wholesale from Core.cpp to
LinuxEmulation's ThreadManager.cpp. Which this manages the lifetimes of
both the OS threads and the FEXCore thread state objects.
One feature lost was the instruction capability, but this was already
buggy and is going to be rewritten/fixed when gdbserver work continues.
Now that all of this management is moved to the frontend, the gdbserver
can start improving since it can start managing all thread state
directly.
Similar to #3284 but works around some of the bugs that one introduced.
This is the minimal amount of changes to move the ownership from FEXCore
to the frontend. Since the frontends don't yet have a full thread state
tracking, there is an opaque pointer that needs to be managed.
In the followup commits this will be changed to have the syscall handler
to be the thread object manager.
The frontend needs to be in control of how threads are created. This is
inherent to the fact that OS threads are OS specific. We currently have
this weird split that when initializing the FEXCore context, we create a
parent thread at all times.
This does some initial cleanup that gets the core initialization nearly
decoupled.
Paulo Matos