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abc9: uniquify blackboxes like whiteboxes (#2695) 

* abc9_ops: uniquify blackboxes too

* abc9_ops: update comment

* abc9_ops: allow bypass for param-less blackboxes

* Add tests
This commit is contained in:
Eddie Hung 2021-03-29 22:02:06 -07:00 committed by GitHub
parent 55dc5a4e4f
commit 8c5f379435
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2 changed files with 62 additions and 11 deletions
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16
passes/techmap/abc9_ops.cc
View File

@ -189,8 +189,6 @@ void prep_hier(RTLIL::Design *design, bool dff_mode)
derived_type = inst_module->derive(design, cell->parameters);
derived_module = design->module(derived_type);
}
if (derived_module->get_blackbox_attribute(true /* ignore_wb */))
continue;
if (derived_module->get_bool_attribute(ID::abc9_flop)) {
if (!dff_mode)
@ -799,14 +797,12 @@ void prep_xaiger(RTLIL::Module *module, bool dff)
if (!box_module->get_bool_attribute(ID::abc9_box))
continue;
if (!cell->parameters.empty())
// At this stage of the ABC9 flow, all modules must be nonparametric, because ABC itself requires concrete netlists, and the presence of
// parameters implies a non-concrete netlist. This error needs some explaining, because there are (at least) two ways to get this:
// 1) You have an (* abc9_box *) parametric whitebox but due to a bug somewhere this hasn't been monomorphised into a concrete blackbox.
// This is a bug, and a bug report would be welcomed.
// 2) You have an (* abc9_box *) parametric blackbox (e.g. to store associated cell data) but want to provide timing data for ABC9.
// This is not supported due to the presence of parameters. If you want to store associated cell data for a box, one approach could be
// to techmap the parameters to constant module inputs, and then after ABC9 use _TECHMAP_CONSTVAL_XX_ to retrieve the values again.
log_error("Black box '%s' is marked (* abc9_box *) and has parameters, which is forbidden in prep_xaiger\n", log_id(cell_name));
{
// At this stage of the ABC9 flow, all modules must be nonparametric, because ABC itself requires concrete netlists, and the presence of
// parameters implies a non-concrete netlist. This means an (* abc9_box *) parametric module but due to a bug somewhere this hasn't been
// uniquified into a concrete parameter-free module. This is a bug, and a bug report would be welcomed.
log_error("Not expecting parameters on module '%s' marked (* abc9_box *)\n", log_id(cell_name));
}
log_assert(box_module->get_blackbox_attribute());
cell->attributes[ID::abc9_box_seq] = box_count++;

57
tests/various/abc9.ys
View File

@ -90,7 +90,7 @@ $_DFF_N_ ff4(.C(clk), .D(1'b1), .Q(z));
endmodule
EOT
simplemap
equiv_opt abc9 -lut 4 -dff
equiv_opt -assert abc9 -lut 4 -dff
design -load postopt
cd abc9_test038
select -assert-count 3 t:$_DFF_N_
@ -99,3 +99,58 @@ clean
select -assert-count 2 a:init
select -assert-count 1 w:w a:init %i
select -assert-count 1 c:ff4 %co c:ff4 %d %a a:init %i
# Check that non-dangling ABC9 black-boxes are preserved
design -reset
read_verilog -specify <<EOT
(* abc9_box, blackbox *)
module mux_with_param(input I0, I1, S, output O);
parameter P = 0;
specify
(I0 => O) = P;
(I1 => O) = P;
(S => O) = P;
endspecify
endmodule
module abc9_test039(output O);
mux_with_param #(.P(1)) m (
.I0(1'b1),
.I1(1'b1),
.O(O),
.S(1'b0)
);
endmodule
EOT
abc9 -lut 4
cd abc9_test039
select -assert-count 1 t:mux_with_param
# Check that dangling ABC9 black-boxes are swept away
design -reset
read_verilog -specify <<EOT
(* abc9_box, blackbox *)
module mux_with_param(input I0, I1, S, output O);
parameter P = 0;
specify
(I0 => O) = P;
(I1 => O) = P;
(S => O) = P;
endspecify
endmodule
module abc9_test040(output O);
wire w;
mux_with_param #(.P(1)) m (
.I0(1'b1),
.I1(1'b1),
.O(w),
.S(1'b0)
);
endmodule
EOT
abc9 -lut 4
cd abc9_test040
select -assert-count 0 t:mux_with_param