Source locations move off the attribute dict into a dedicated SrcRef on
AttrObject, interned in a per-design SrcPool that hash-conses sets of
location twines. Locations share their file prefix with each other through
the twine pool, and objects that fuse (opt_merge, share, ff/mem rewrites)
carry the union of their inputs' locations instead of a '|'-joined string.
write_rtlil emits an `srcs` section of location sets alongside `twines`;
read_rtlil resolves `\src "@N"` back to a handle and still accepts a plain
location string. -readable renders the locations as text.
These can be used to protect undefined flip-flop initialization values
from optimizations that are not sound for formal verification and can
help mapping all solver-provided values in witness traces for flows that
use different backends simultaneously.
- FfData now keeps track of the module and underlying cell, if any (so
calling emit on FfData created from a cell will replace the existing cell)
- FfData implementation is split off to its own .cc file for faster
compilation
- the "flip FF data sense by inserting inverters in front and after"
functionality that zinit uses is moved onto FfData class and beefed up
to have dffsr support, to support more use cases
Emil J. Tywoniak
Codexplorer
Robert O'Callahan
Jannis Harder
Marcelina Kościelnicka