This symbol is defined as a static member object inside of a
boost detail header. When boost headers are used in a project
that uses Boost in both the main binary as well as dlopen()'d
shlibs, the top_ symbol gets duplicated and the metadata gets
partitioned.
We use the Boost shlib to unify both the main binary and the
shlibs to use the same memory address for top_.
This involves marking the templated object call_stack::top_ as
"extern" and then declaring to Boost that we intend to use the
shlibs.
This makes the initialization sequence much cleaner and conceptually
well encapsulated.
We also now dynamically allocate the Mind objects. They're allocated
dynamically by Mrntt inside of initializeReq. This means that we no
longer have to worry about jolting and cleaning up the running threads
of global mind object even when we never explicitly called
Mind.initializeReq.
Along with other conceptual improvements to our abstractions, this
patch also gets us to a real "end of program initialization" point
for the first time.
We now allocate globalMind locally inside of marionetteMain. Why?
Before now, we had an asymmetric threading situation where the
globalMind's threads were initialized at during global constructor
invocation and not on demand. This meant that we had to shut down
those threads even if we had never got to the point of calling
Mind::initializeReq.
This significantly complicated our shutdown sequence since we had
to factor in the lifetime of the std::thread objects inside of the
ComponentThreads which were inside of the globalMind object.
Now, if we hadn't called Mind::initializeReq, we don't have to
perform any Mind::finalizeReq or adjacent operations. Shutdown is
symmetrically mirrored against the operations we actually performed
during execution.
We introduced some complexity by splitting ComponentThreads into
two derivative types (MindThread and MarionetteThread) but I think
in the long term we'll be able to massage this split into a much
cleaner situation overall.
Now we have modularized the Mind class to contain all of its
ComponentThreads. This enables us to run multiple mind instances
within the same SMO process, at least in theory.
We probably won't actually do this, but we want to ensure that the
design is clean enough to enable it.
This allows us to execute an op on all mind threads without having
to repeatedly write loops. We've implemented wrappers to handle
start, pause, resume, exit and JOLT sequences.
This commit significantly restructures the way we setup threading in
SMO. We now don't use the CRT main() thread at all. It's only used
as a mechanism to ensure that Marionette doesn't execute before
global constructors have been executed.
JOLTing:
This is a simple ASIO post()ed message that makes each thread setup
its thread-local data pointer to its own ComponentThread object,
and then enter its main ASIO run() loop to await commands from
Marionette.
Exception bubbling:
We now cleanly cause mind threads to report their exceptions
to marionette, so that marionette can cleanly shut the mind down
in an orderly fashion.
Thread Control messaging API:
A namespace of asynchronous messages to be post()ed to threads to
control them. It enables us to pause and resume threads. This will
be very useful for Marionette when we add the ability for it to
suspend Salmanoff's running mind, inject new goals, inspect current
state, etc; and then resume the mind's execution.