Avoids errors in trailing comma handling, broken indentation and
improper escaping that is common when building JSON by manually
concatenating strings.
This contains parsing code as well as generic routines to associate the
hierarchical signals paths within a Yosys witness file to a loaded RTLIL
design, including support for memories.
This adds the xprop_decoder attribute to bwmuxes that drive the original
unencoded signals. Setundef is changed to ignore the x inputs of these
bwmuxes, so that they survive the prep script of SBY's formal flow. This
is required to make simulation (via sim) using the prep model show the
decoded x signals instead of 0/1 values made up by the solver.
This makes it possible for yosys commands to return values when invoked
as tcl commands. Right now no commands natively support this, but the
tee command can be used with json output like this:
```tcl
set stat [yosys tee -q -s result.json stat -json -top top]
dict get $stat modules \\top num_cells_by_type \$pmux
```
Or with newline separated lists like this:
```tcl
split [yosys tee -q -s result.string select -list top] "\n"
```
The new bitwise case equality (`$bweqx`) and bitwise mux (`$bwmux`)
cells enable compact encoding and decoding of 3-valued logic signals
using multiple 2-valued signals.
When writing VCDs smtbmc replaces square brackets with angle brackets to
avoid the issues with VCD readers misinterpreting such signal names.
For memory addresses it also uses angle brackets and hexadecimal
addresses, while other tools will use square brackets and decimal
addresses.
Previously the code handled both forms of memory addresses, assuming
that any signal that looks like a memory address is a memory address.
This is not the case when the user uses regular signals whose names
include square brackets _or_ when the verific frontend generates such
names to represent various constructs.
With this change all angular brackets are turned into square brackets
when reading the trace _and_ when performing a signal lookup. This means
no matter which kind of brackets are used in the design or in the VCD
signals will be matched. This will not handle multiple signals that are
the same apart from replacing square/angle brackets, but this will cause
issues during the VCD writing of smtbmc already.
It still uses the distinction between square and angle brackets for
memories to decide whether the address is hex or decimal, but even if
something looks like a memory and is added to the `memory_to_handle`
data, the plain signal added to `name_to_handle` is used as-is, without
rewriting the address.
This last change is needed to successfully match verific generated
signal names that look like memory addresses while keeping memories
working at the same time. It may cause regressions when VCD generation
was done with a design that had memories but simulation is done with a
design where the memories were mapped to registers. This seems like an
unusual setup, but could be worked around with some further changes
should this be required.
* Change simlib's $mux cell to use the ternary operator as $_MUX_
already does
* Stop opt_expr -keepdc from changing S=x to S=0
* Change const eval of $mux and $pmux to match the updated simlib
(fixes sim)
* The sat behavior of $mux already matches the updated simlib
The verilog frontend uses $mux for the ternary operators and this
changes all interpreations of the $mux cell (that I found) to match the
verilog simulation behavior for the ternary operator. For 'if' and
'case' expressions the frontend may also use $mux but uses $eqx if the
verilog simulation behavior is requested with the '-ifx' option.
For $pmux there is a remaining mismatch between the sat behavior and the
simlib behavior. Resolving this requires more discussion, as the $pmux
cell does not directly correspond to a specific verilog construct.
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.
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.
This pull request is to address YosysHQ/yosys#2980.
The documentation, as originally written, does not make it clear that yosys commands, when used within a tcl script, do not return any value to the tcl script.
This pull request notes this and offers a workaround via tee as noted in the issue.
Jannis Harder
Miodrag Milanović
N. Engelhardt
KrystalDelusion
KrystalDelusion
Emil J
Claire Xenia Wolf
Aki Van Ness
Marcelina Kościelnicka
rockybulwinkle