Teach V3Localize how to localize variables that are used in multiple
functions, if in all functions where they are used, they are always
written in whole before being consumed. This allows a lot more variables
to be localized (+20k variables on OpenTitan - when building without
--trace), and can cause significant performance improvement (OpenTitan
simulates 8.5% - build single threaded and withuot --trace).
What previously used to be per module static constants created in
V3Table and V3Prelim are now merged globally within the whole model and
emitted as part of a separate constant pool. Members of the constant
pool are global variables which are declared lazily when used (similar to
loose methods).
This patch introduces the concept of 'loose' methods, which semantically
are methods, but are declared as global functions, and are passed an
explicit 'self' pointer. This enables these methods to be declared
outside the class, only when they are needed, therefore removing the
header dependency. The bulk of the emitted model implementation now uses
loose methods.
A few names were incorrectly mangled, which made --protect-ids produce
invalid output when certain SV class constructs were uses. Now fixed and
added a few extra tests to catch this.
CFuncs only used to be split at procedure (always/initial/final block),
which on occasion can still yield huge output files if they have large
procedures. This patch make CFuncs split at statement boundaries within
procedures. This has the potential to help a lot, but still does not
help if there are huge statements within procedures.
