yosys/docs/source/code_examples/fifo/fifo.ys

# ========================================================
# throw in some extra text to match what we expect if we were opening an
# interactive terminal
log $ yosys fifo.v
log 
log -- Parsing `fifo.v' using frontend ` -vlog2k' --
read_verilog -defer fifo.v

# turn command echoes on to use the log output as a console session
echo on
hierarchy -top addr_gen
show -notitle -format dot -prefix addr_gen_hier

# ========================================================
proc
show -notitle -format dot -prefix addr_gen_proc

# ========================================================
design -reset
read_verilog fifo.v
hierarchy -check -top fifo
proc
show -notitle -format dot -prefix rdata_proc o:rdata %ci*

# ========================================================

flatten
show -notitle -format dot -prefix rdata_flat o:rdata %ci*

# ========================================================

opt_clean
show -notitle -format dot -prefix fifo_flat

design -reset
read_verilog fifo.v
synth_ice40 -dsp -top fifo
show -notitle -format dot -prefix fifo_synth
stat