yosys/passes/cmds/clean_zerowidth.cc

211 lines
6.9 KiB
C++

/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2021 Marcelina Kościelnicka <mwk@0x04.net>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*/
#include "kernel/yosys.h"
#include "kernel/celltypes.h"
#include "kernel/mem.h"
USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN
struct CleanZeroWidthPass : public Pass {
CleanZeroWidthPass() : Pass("clean_zerowidth", "clean zero-width connections from the design") { }
void help() override
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" clean_zerowidth [selection]\n");
log("\n");
log("Fixes the selected cells and processes to contain no zero-width connections.\n");
log("Depending on the cell type, this may be implemented by removing the connection,\n");
log("widening it to 1-bit, or removing the cell altogether.\n");
log("\n");
}
void clean_case(RTLIL::CaseRule *cs)
{
std::vector<SigSig> new_actions;
for (auto &action : cs->actions)
if (GetSize(action.first) != 0)
new_actions.push_back(action);
std::swap(new_actions, cs->actions);
for (auto sw : cs->switches)
for (auto scs : sw->cases)
clean_case(scs);
}
void execute(std::vector<std::string> args, RTLIL::Design *design) override
{
size_t argidx;
for (argidx = 1; argidx < args.size(); argidx++)
{
break;
}
extra_args(args, argidx, design);
CellTypes ct;
ct.setup();
for (auto module : design->selected_modules())
{
for (auto cell : module->selected_cells())
{
if (!ct.cell_known(cell->type)) {
// User-defined cell: just prune zero-width connections.
for (auto it: cell->connections()) {
if (GetSize(it.second) == 0) {
cell->unsetPort(it.first);
}
}
} else if (RTLIL::builtin_ff_cell_types().count(cell->type)) {
// Coarse FF cells: remove if WIDTH == 0 (no outputs).
// This will also trigger on fine cells, so use the Q port
// width instead of actual WIDTH parameter.
if (GetSize(cell->getPort(ID::Q)) == 0) {
module->remove(cell);
}
} else if (cell->type == ID($pmux)) {
// Remove altogether if WIDTH is 0, replace with
// a connection if S_WIDTH is 0.
if (cell->getParam(ID::WIDTH).as_int() == 0) {
module->remove(cell);
}
if (cell->getParam(ID::S_WIDTH).as_int() == 0) {
module->connect(cell->getPort(ID::Y), cell->getPort(ID::A));
module->remove(cell);
}
} else if (cell->type == ID($concat)) {
// If a concat has a zero-width input: replace with direct
// connection to the other input.
if (cell->getParam(ID::A_WIDTH).as_int() == 0) {
module->connect(cell->getPort(ID::Y), cell->getPort(ID::B));
module->remove(cell);
} else if (cell->getParam(ID::B_WIDTH).as_int() == 0) {
module->connect(cell->getPort(ID::Y), cell->getPort(ID::A));
module->remove(cell);
}
} else if (cell->type == ID($fsm)) {
// TODO: not supported
} else if (cell->is_mem_cell()) {
// Skip — will be handled below.
} else if (cell->type == ID($lut)) {
// Zero-width LUT is just a const driver.
if (cell->getParam(ID::WIDTH).as_int() == 0) {
module->connect(cell->getPort(ID::Y), cell->getParam(ID::LUT)[0]);
module->remove(cell);
}
} else if (cell->type == ID($sop)) {
// Zero-width SOP is just a const driver.
if (cell->getParam(ID::WIDTH).as_int() == 0) {
// The value is 1 iff DEPTH is non-0.
bool val = cell->getParam(ID::DEPTH).as_int() != 0;
module->connect(cell->getPort(ID::Y), val);
module->remove(cell);
}
} else if (cell->hasParam(ID::WIDTH)) {
// For cells with WIDTH parameter: remove if zero.
if (cell->getParam(ID::WIDTH).as_int() == 0) {
module->remove(cell);
}
} else if (cell->hasParam(ID::Y_WIDTH)) {
// For most operators: remove if Y width is 0, expand
// A and B to 1-bit if their width is 0.
if (cell->getParam(ID::Y_WIDTH).as_int() == 0) {
module->remove(cell);
} else if (cell->type == ID($macc)) {
// TODO: fixing zero-width A and B not supported.
} else {
if (cell->getParam(ID::A_WIDTH).as_int() == 0) {
cell->setPort(ID::A, State::S0);
cell->setParam(ID::A_WIDTH, 1);
}
if (cell->hasParam(ID::B_WIDTH) && cell->getParam(ID::B_WIDTH).as_int() == 0) {
cell->setPort(ID::B, State::S0);
cell->setParam(ID::B_WIDTH, 1);
}
}
}
}
// NOTE: Zero-width switch signals are left alone for processes, as there
// is no simple way of cleaning them up.
for (auto &it: module->processes) {
if (!design->selected(module, it.second))
continue;
clean_case(&it.second->root_case);
for (auto sync : it.second->syncs) {
std::vector<int> swizzle;
std::vector<RTLIL::MemWriteAction> new_memwr_actions;
for (int i = 0; i < GetSize(sync->mem_write_actions); i++) {
auto &memwr = sync->mem_write_actions[i];
if (GetSize(memwr.data) == 0)
continue;
if (GetSize(memwr.address) == 0)
memwr.address = State::S0;
Const priority_mask;
for (auto x : swizzle) {
priority_mask.bits.push_back(memwr.priority_mask.bits[x]);
}
memwr.priority_mask = priority_mask;
swizzle.push_back(i);
new_memwr_actions.push_back(memwr);
}
std::swap(new_memwr_actions, sync->mem_write_actions);
std::vector<SigSig> new_actions;
for (auto &action : sync->actions)
if (GetSize(action.first) != 0)
new_actions.push_back(action);
std::swap(new_actions, sync->actions);
}
}
for (auto &mem : Mem::get_selected_memories(module)) {
if (mem.width == 0) {
mem.remove();
continue;
}
for (auto &init : mem.inits) {
if (GetSize(init.addr) == 0) {
init.addr = State::S0;
}
}
for (auto &port : mem.rd_ports) {
if (GetSize(port.addr) == 0) {
port.addr = State::S0;
}
}
for (auto &port : mem.wr_ports) {
if (GetSize(port.addr) == 0) {
port.addr = State::S0;
}
}
mem.emit();
}
std::vector<SigSig> new_conns;
for (auto &conn : module->connections())
if (GetSize(conn.first) != 0)
new_conns.push_back(conn);
module->new_connections(new_conns);
}
}
} CleanZeroWidthPass;
PRIVATE_NAMESPACE_END