python: Remove getCode() type workaround

Python 2.7 requires a workaround when wrapping exit objects to
explicitly convert the return of getCode() to int to not confuse
sys.exit. This workaround isn't needed and doesn't work on Python 3
since it doesn't have a separate long integer type.

Change-Id: I57bc3fd8f4699676c046ece8a52baa2796959ffd
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/15978
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>

misc: Rename misc.(hh|cc) to logging.(hh|cc)

These files aren't a collection of miscellaneous stuff, they're the
definition of the Logger interface, and a few utility macros for
calling into that interface (panic, warn, etc.).

Change-Id: I84267ac3f45896a83c0ef027f8f19c5e9a5667d1
Reviewed-on: https://gem5-review.googlesource.com/6226
Reviewed-by: Brandon Potter <Brandon.Potter@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>

python: Make GlobalExitEvent.getCode() return an int

PyBind normally casts integers returned from the C to long in
Python. This is normally fine since long in most cases behaves just
like an int. However, when passing the return value from getcode() to
sys.exit, unexpected behavior ensues. Due to the way the function is
defined, any type other than int (with the exception of None) will be
treated as an error and be equivalent to sys.exit(1).

Since we frequently use the sys.exit(event.getCode()) pattern, we need
to ensure that the function returns an integer. This change adds an
explicit type conversion to a Python integer in the wrapper code.

Change-Id: I73d6b881025064afa2b2e6eb4512fa2a4b0a87da
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jose Marinho <jose.marinho@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/4280
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Joe Gross <joe.gross@amd.com>

python: Fix PyEvent reference counting bug

The current implementation of reference counting for PyEvents only
partially works. The native object is currently kept alive while it is
in the event queue. However, if the Python object goes out of scope,
the Python side of this object is garbage collected which leaves a
"dangling" native object. This results in confusing error messages
where PyBind is unable to find the Python implementation of an event
when it is triggered.

Implement reference counting using the generalized reference counting
API instead.

Change-Id: I4e8e04abc4f61dff238d718065f5371e73b38ab3
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/3222
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

python: Use PyBind11 instead of SWIG for Python wrappers

Use the PyBind11 wrapping infrastructure instead of SWIG to generate
wrappers for functionality that needs to be exported to Python. This
has several benefits:

* PyBind11 can be redistributed with gem5, which means that we have
full control of the version used. This avoid a large number of
hard-to-debug SWIG issues we have seen in the past.

* PyBind11 doesn't rely on a custom C++ parser, instead it relies on
wrappers being explicitly declared in C++. The leads to slightly
more boiler-plate code in manually created wrappers, but doesn't
doesn't increase the overall code size. A big benefit is that this
avoids strange compilation errors when SWIG doesn't understand
modern language features.

* Unlike SWIG, there is no risk that the wrapper code incorporates
incorrect type casts (this has happened on numerous occasions in
the past) since these will result in compile-time errors.

As a part of this change, the mechanism to define exported methods has
been redesigned slightly. New methods can be exported either by
declaring them in the SimObject declaration and decorating them with
the cxxMethod decorator or by adding an instance of
PyBindMethod/PyBindProperty to the cxx_exports class variable. The
decorator has the added benefit of making it possible to add a
docstring and naming the method's parameters.

The new wrappers have the following known issues:

* Global events can't be memory managed correctly. This was the
case in SWIG as well.

Change-Id: I88c5a95b6cf6c32fa9e1ad31dfc08b2e8199a763
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Andrew Bardsley <andrew.bardsley@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2231
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Pierre-Yves Péneau <pierre-yves.peneau@lirmm.fr>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>