This is not valid when the prefix of a trace already violates
assertions. This can happen when the trace generating solver doesn't
look for a minimal length counterexample.
I have added an optional flag to smtbmc that causes failed temporal induction counterexample traces to be checked for duplicate states and reported to the user, since loops in the counterexample mean that increasing the induction depth won't help prove a design's safety properties.
The witness metadata was missing fine grained FFs completely and for
coarse grained FFs where the output connection has multiple chunks it
lacked the offset of the chunk within the SMT expression. This fixes
both, the later by adding an "smtoffset" field to the metadata.
This adds a native json based witness trace format. By having a common
format that includes everything we support, and providing a conversion
utility (yosys-witness) we no longer need to implement every format for
every tool that deals with witness traces, avoiding a quadratic
opportunity to introduce subtle bugs.
Included:
* smt2: New yosys-smt2-witness info lines containing full hierarchical
paths without lossy escaping.
* yosys-smtbmc --dump-yw trace.yw: Dump results in the new format.
* yosys-smtbmc --yw trace.yw: Read new format as constraints.
* yosys-witness: New tool to convert witness formats.
Currently this can only display traces in a human-readable-only
format and do a passthrough read/write of the new format.
* ywio.py: Small python lib for reading and writing the new format.
Used by yosys-smtbmc and yosys-witness to avoid duplication.
This attribute can be used by formal backends to indicate which clocks
were mapped to the global clock. Update the btor and smt2 backend which
already handle clock inputs to understand this attribute.
This approach had major issues with ROMs whose initialization was not
fully defined. If required, memory_map -rom-only -keepdc should be
called early in a formal flow instead. (This does require a careful
choice of optimization passes though. Sby's scripts will be updated
accordingly.)
This essentially adds wide port support for free in passes that don't
have a usefully better way of handling wide ports than just breaking
them up to narrow ports, avoiding "please run memory_narrow" annoyance.
There will soon be more (versioned) memory cells, so handle passes that
only care if a cell is memory-related by a simple helper call instead of
a hardcoded list.
Jannis Harder
Emil J
Miodrag Milanovic
Jacob Lifshay
N. Engelhardt
Claire Xenia Wolf
Marcelina Kościelnicka
GCHQDeveloper560
Jakob Wenzel
N. Engelhardt
whitequark
Noah Moroze