yosys/tests/techmap/techmap_replace.ys

read_verilog <<EOT
module sub(input i, output o, input j);
foobar _TECHMAP_REPLACE_(i, o, j);
wire _TECHMAP_REPLACE_.asdf = i ;
barfoo _TECHMAP_REPLACE_.blah (i, o, j);
endmodule
EOT
design -stash techmap

read_verilog <<EOT
module top(input i, output o);
sub s0(i, o);
endmodule
EOT

techmap -map %techmap
select -assert-any w:s0.asdf
select -assert-any c:s0.blah