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.
There is no strong need to re-map LogicMTask IDs and it just adds extra
processing. Instead we just allocate a separate set of ExecMTask IDs as
they are created, which can also be used as the unique profiling ID as
well. The only effect on the output of this is the change in mtask IDs
emitted, which was fairly arbitrary to begin with.
The typical find/if-not-exists-insert pattern can be achieved with 1
lookup instead of 2 using emplace with a sentinel value. Also maps value
initialize their values when inserted with the [] operator, this is
defined and so there is no need to explicitly insert zeroes for integer
values.
Since we removed --threads 0 support, the 'threads()' option always
returns a value >= 1. Remove corresponding dead code.
Some of the coverage counters appear to use atomics even if the model is
single threaded. I'm under the impression this was a bug originally so
those ones I changed to use threads() > 1 instead.
Geza Lore
Wilson Snyder
Bartłomiej Chmiel
Ryszard Rozak
Ibrahim Burak Yorulmaz
Andrew Nolte
Natan Kreimer
github action
Krzysztof Starecki
Mariusz Glebocki
Arkadiusz Kozdra
Andrew Nolte
Todd Strader
Marlon James
Krzysztof Boroński