OpenSTA/search/FindClkPins.cc

125 lines
2.9 KiB
C++

// OpenSTA, Static Timing Analyzer
// Copyright (c) 2020, Parallax Software, Inc.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
#include "Sta.hh"
#include "Network.hh"
#include "Graph.hh"
#include "Bfs.hh"
#include "Sdc.hh"
#include "SearchPred.hh"
#include "Search.hh"
namespace sta {
void
Sta::ensureClkPins()
{
if (!clk_pins_valid_) {
ensureLevelized();
findClkPins();
clk_pins_valid_ = true;
}
}
void
Sta::clkPinsInvalid()
{
clk_pins_valid_ = false;
clk_pins_.clear();
ideal_clk_pins_.clear();
}
void
Sta::clkPinsDisconnectPinBefore(Vertex *vertex)
{
// If the pin is in the clock network but not a clock endpoint
// everything downstream is invalid.
if (clk_pins_.hasKey(vertex->pin())
&& !isClkEnd(vertex, graph_))
clk_pins_valid_ = false;
}
void
Sta::clkPinsConnectPinAfter(Vertex *vertex)
{
// If the pin fanin is part of the clock network
VertexInEdgeIterator edge_iter(vertex, graph_);
while (edge_iter.hasNext()) {
Edge *edge = edge_iter.next();
Vertex *from = edge->from(graph_);
if (clk_pins_.hasKey(from->pin())) {
clk_pins_valid_ = false;
break;
}
}
}
// Find clock network pins.
// This is not as reliable as Search::isClock but is much cheaper.
void
Sta::findClkPins()
{
// Use two passes to find ideal and propagated clock network pins.
findClkPins(false, clk_pins_);
findClkPins(true, ideal_clk_pins_);
}
void
Sta::findClkPins(bool ideal_only,
PinSet &clk_pins)
{
ClkArrivalSearchPred srch_pred(this);
BfsFwdIterator bfs(BfsIndex::other, &srch_pred, this);
for (Clock *clk : sdc_->clks()) {
if (!ideal_only
|| !clk->isPropagated()) {
for (Pin *pin : clk->leafPins()) {
if (!ideal_only
|| !sdc_->isPropagatedClock(pin)) {
Vertex *vertex, *bidirect_drvr_vertex;
graph_->pinVertices(pin, vertex, bidirect_drvr_vertex);
bfs.enqueue(vertex);
if (bidirect_drvr_vertex)
bfs.enqueue(bidirect_drvr_vertex);
}
}
}
}
while (bfs.hasNext()) {
Vertex *vertex = bfs.next();
Pin *pin = vertex->pin();
if (!sdc_->isPropagatedClock(pin)) {
clk_pins.insert(pin);
bfs.enqueueAdjacentVertices(vertex);
}
}
}
bool
Sta::isClock(Pin *pin) const
{
return clk_pins_.hasKey(pin);
}
bool
Sta::isIdealClock(Pin *pin) const
{
return ideal_clk_pins_.hasKey(pin);
}
} // namespace