systemc: Hook up gem5_getPort to the gem5 getPort mechanism.

Change-Id: I771607c4436f4c1ca9d355d1da52924308cfc3b3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17229
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Change how SC_BIND_PROXY_NIL is initialized.

The previous implementation dereferenced a null pointer to create a
reference which would then have its address taken in the sc_bind_proxy
constructor. clang says that that uses undefined behavior, so this
change adds a default constructor which initializes the two contained
pointers to null explicitly.

We have to hope systemc code doesn't play around with sc_bind_proxy too
much and doesn't accidentally use this constructor unintentionally, but
it seems like the least bad possible solution which makes clang happy.

Change-Id: Ic59603495fe7a406586a18ce44de979f84089bcd
Reviewed-on: https://gem5-review.googlesource.com/c/13879
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some deprecated positional binding operators.

These are used in one of the tests, specifically the comma operator. It
didn't cause compilation to fail because of the default meaning of the
comma.

Change-Id: I7ce7fe74f02d4ad6a4ab896a2f0d6bd1ce635c2f
Reviewed-on: https://gem5-review.googlesource.com/c/13298
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Handle nonstandard cthread sensitivities.

Accellera allows some non-standard values in the second position of the
SC_CTHREAD macro. Do that as well, with the same special handling which
automatically selects the positive edge of boolean ports/interfaces.

Change-Id: I79594980898a17afc30fea6f77384589cbc3c250
Reviewed-on: https://gem5-review.googlesource.com/c/12809
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Centralize module callbacks and report new warnings.

By centralizing module callbacks, the gem5 module class knows when
different stages of the simulation are happening and can do it's own
extra checks. It also compartmentalizes modules more since the kernel
object doesn't have to reach into them to enumerate ports and exports.

Change-Id: I55887284af9c05150fe9d054f5b6147cad6092a1
Reviewed-on: https://gem5-review.googlesource.com/c/12610
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Raise an error when SC_METHOD, etc. is used after starting.

Those mechanisms for creating processes are only allowed before the
end of elaboration, or in other words before sc_start is called.
Technically the check in Accellera's implementation won't trigger if
the simulation is stopped, and we immitate that behavior.

Change-Id: I9b8b5bd32f876781b6e0d5c0ee0e09de19bdabc1
Reviewed-on: https://gem5-review.googlesource.com/c/12447
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Implement positional binding.

Change-Id: Ifbcd7e4148b82b9bf5241e040e812925daea3705
Reviewed-on: https://gem5-review.googlesource.com/12263
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Make sc_process_b less hokey, and make WAIT* work.

This change puts sc_process_b into the inheritance hierarchy for the
Process types. It also adds the nonstandard sc_set_location function
and calls it from the nonstandard WAIT* macros.

Change-Id: Ic997dcf74d262774dd7b53504146e372e03af2e0
Reviewed-on: https://gem5-review.googlesource.com/12259
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Implement the various sc_module stage callbacks.

This change also gets rid of the SystemC namespace which was
deprecated in favor of sc_gem5.

A few utility functions which check whether certain callbacks have
finished were also implemented. status tracking moved from a global
variable in sc_main.cc to a member of the kernel simobject.

Change-Id: I50967fae9c576fbe45b1faff587aaa824857a289
Reviewed-on: https://gem5-review.googlesource.com/12033
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Fill out sc_process_handle and create Process classes.

The sc_process_handle class now primarily delegates to a Process object
it points at. The Process object does book keeping as far as its
internal state, but doesn't yet have a way to run its target function
or to schedule itself or inject exceptions into its context of
execution.

Change-Id: I98389778abe29aa26e3e3a91bf02e6721acc8a9c
Reviewed-on: https://gem5-review.googlesource.com/11613
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Implement some basic plumbing in sc_module.hh.

Take care of some low hanging fruit as far as wrapper methods and
the sc_bind_proxy class.

Change-Id: I7f55a37eeaa82338bd608218c0261fbc39e65fc2
Reviewed-on: https://gem5-review.googlesource.com/11612
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the nonstandard sc_hierarchical_name_exists function.

Change-Id: I1340bb6cb0ae29d81b5d73b3dd39ebb11c14802c
Reviewed-on: https://gem5-review.googlesource.com/11280
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the nonstandard timed_out function.

Change-Id: If14a5f98f03448c712827b7f92d2a36992541518
Reviewed-on: https://gem5-review.googlesource.com/11279
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some deprecated sc_module constructors.

Change-Id: Ibe2bfe63536af33fca6040f4aef999ee928d876b
Reviewed-on: https://gem5-review.googlesource.com/11278
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some nonstandard cthread related sc_module functions.

Change-Id: I73f9868b80f9b75e7bd90df6e894daea60a203a1
Reviewed-on: https://gem5-review.googlesource.com/11268
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the nonstandard, undocumented halt function.

Used in the tests.

Change-Id: I9b4f10600a50e0def1b5d55428cb4ad49e401295
Reviewed-on: https://gem5-review.googlesource.com/11263
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add some nonstandard SC_WAIT* macros.

These are not in the standard, but are defined by Accellera and used in
the tests.

Change-Id: I4cbddac4eb75c58d8ae3eb77d1f291dac3c51cd6
Reviewed-on: https://gem5-review.googlesource.com/11261
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the nonstandard macro SC_NEW.

This is in the Accellera implementation and in the regression tests.
The implementation here is a bit different than theirs in that it uses
std::unique_ptrs.

Change-Id: Id3d1ad82482b94a5d99f27e02d1e447ca1944797
Reviewed-on: https://gem5-review.googlesource.com/11255
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Add the deprecated sc_module::end_module function.

The regression tests use this function. In the Accellera implementation
it seems to just do some error checking, so our version doesn't do
anything for now.

Change-Id: Icaad45e934bad69e301bc0234f73e69791940736
Reviewed-on: https://gem5-review.googlesource.com/10854
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

systemc: Seperate the "external" header interface.

Most (but not all) of the SystemC headers are part of the "external"
interface that an existing, standard compliant module would include
through <systemc.h> or <systemc>. Since those follow slightly different
rules (relative includes, no gem5 includes), this change separates them
out so that they're easier to identify.

Also, this change moves the other files into a "core" subdirectory,
with the intention to add a "dt", aka data type, directory some time in
the future when those standard defined types are implemented.

Change-Id: Ida63f9cc0bc0431024d4dd691cc5b22b944a99a8
Reviewed-on: https://gem5-review.googlesource.com/10835
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Gabe Black <gabeblack@google.com>