The loops modelling the SystemVerilog scheduling regions are no longer
generated. They now live in 'VerilatedEvalLoop' in the runtime library.
The generated model holds one as a member, passing itself to it, and
exposes each evaluation entry point to it as a pure virtual method on
VerilatedModel. The model's 'eval' and 'eval_step' remain the top level
entry points, and are backward compatible.
V3Sched no longer emits '_eval' or '_eval_settle', etc.. Instead every
evaluation entry point called from the runtime is enumerated by 'VEval',
Scheduling creates all entry points, for all scheduling regions, even if
they are empty, and the runtime eval loop calls everything
unconditionally. If regions are empty, this is simply a call to an empty
function. This will hurt performance on very small models, but should
not be noticeable on anything meaningful, so it is likely best to keep
to reduce complexity.
A scheduling entry points evaluate a single iteration and returns
whether it did any work, they are effectively the previous
`_eval_phase_*` functions.
Combined the 3 various APIs used in EmitC* passes to handle file
opening/splitting into a single one. This removes a lot of copy paste
and makes everything consistent.
All C++ file handling goes through `EmitCBaseVisitor` using the
`openNewOutputHeaderFile`, `openNewOutputSourceFile` and
`closOutputFile` methods.
To emit a new kind of file, always derive a new class from
`EmitCBaseVisitor`, and use the above APIs, they will take care of
everything else in a consistent matter.
Subsequently also removed V3OutSCFile, and instead included
verilated_sc.h (which included the systemc header itself) in the two
files that need it (the primary model header, and the root module
header).
Functional changes:
- The PCH header did not use to have a corresponding AstCFile. Now it
does, though this makes no difference in the output
- All 'slow' sources now have '__Slow' in the name automatically (the
only one missing was for the ConstPool files)
Rest of the output is identical except for the header line now being
present in all generated C++ files.
The Syms class can contain a very large number of VeriltedScope
instances if `--vpi` is used, all of which need a call to the default
constructor in the constructor of the Syms class. This can lead to very
long compilation times, even without optimization on some compilers.
To avoid the constructor calls, hold VeriltedScope via pointers in the
Syms class, and explicitly new and delete them in the Syms
constructor/destructor. These explicit new/delte can then be
automatically split up into sub functions when the Syms
constructor/destructor become large.
Regarding run-time performance, this should have no significant effect,
most interactions are either during construction/destruction of the Syms
object, or are via pointers already. The one place where we used to
refer to VerilatedScope instances is when emitting an AstScopeName for
things like $display %m. For those there will be an extra load
instruction at run-time, which should not make a big difference.
Patch 3 of 3 to fix long compile times of the Syms module in some
scenarios.
Splitting of the Syms constructor/destructor were a bit arbitrarily
enforced with some parts splitable, while others not. There was also an
issue that even if the constructor and destructor bodies were split, we
would still end up with both in the same file that was double the size of
the intended split limit.
To fix, first all statements required in the Syms constructor and
destructor are gathered into a vector, then if the total number of
statements required for both is bigger than the split limit, the
implementations are split into sub-functions, one per file, as before,
ensuring that none of the functions are bigger than the split limit.
Also add __Slow suffix to the names of the files.
Patch 2 of 3 to fix long compile times of the Syms module in some
scenarios.
In order to avoid long compile times of the Syms constructor due to
having a very large number of member constructor sto call, move to using
explicit ctor/dtor functions for all but the root VerilatedModule. The
root module needs a constructor as it has non-default-constructible
members. The other modules don't.
This is only part of the fix, as in order to avoid having a default
constructor call the VerilatedModule needs to be default constructible.
I think this is now true for modules that do not contain strings or
other non trivially constructible/destructible variables.
Patch 1 of 3 to fix long compile times of the Syms module in some
scenarios.
Wilson Snyder
Todd Strader
Geza Lore
Nick Brereton
Jakub Michalski
Yogish Sekhar
Christian Hecken
Christian Hecken
Gilberto Abram
Kaleb Barrett
Geza Lore
Bartłomiej Chmiel
Ryszard Rozak
Ibrahim Burak Yorulmaz
Andrew Nolte
Natan Kreimer
github action
Krzysztof Starecki
