OpenSTA/graph/Graph.cc

// OpenSTA, Static Timing Analyzer
// Copyright (c) 2026, 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/>.
// 
// The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software.
// 
// Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
// 
// This notice may not be removed or altered from any source distribution.

#include "Graph.hh"

#include "ContainerHelpers.hh"
#include "Debug.hh"
#include "FuncExpr.hh"
#include "Liberty.hh"
#include "MinMax.hh"
#include "Mutex.hh"
#include "Network.hh"
#include "PortDirection.hh"
#include "SearchPred.hh"
#include "Stats.hh"
#include "TimingArc.hh"
#include "TimingRole.hh"
#include "Transition.hh"
#include "Variables.hh"

namespace sta {

////////////////////////////////////////////////////////////////
//
// Graph
//
////////////////////////////////////////////////////////////////

Graph::Graph(StaState *sta,
             DcalcAPIndex ap_count) :
  StaState(sta),
  period_check_annotations_(network_),
  reg_clk_vertices_(makeVertexSet(this)),
  ap_count_(ap_count)
{
  // For the benifit of reg_clk_vertices_ that references graph_.
  graph_ = this;
}

Graph::~Graph()
{
  edges_->clear();
  delete edges_;
  vertices_->clear();
  delete vertices_;
  removePeriodCheckAnnotations();
}

void
Graph::makeGraph()
{
  Stats stats(debug_, report_);
  makeVerticesAndEdges();
  makeWireEdges();
  stats.report("Make graph");
}

// Make vertices for each pin.
// Iterate over instances and top level port pins rather than nets
// because network may not connect floating pins to a net
// (ie, Intime occurence tree bleachery).
void
Graph::makeVerticesAndEdges()
{
  vertices_ = new VertexTable;
  edges_ = new EdgeTable;

  LeafInstanceIterator *leaf_iter = network_->leafInstanceIterator();
  while (leaf_iter->hasNext()) {
    const Instance *inst = leaf_iter->next();
    makePinVertices(inst);
    makeInstanceEdges(inst);
  }
  delete leaf_iter;
  makePinVertices(network_->topInstance());
}

class FindNetDrvrLoadCounts : public PinVisitor
{
public:
  FindNetDrvrLoadCounts(Pin *drvr_pin,
                        PinSet &visited_drvrs,
                        int &drvr_count,
                        int &bidirect_count,
                        int &load_count,
                        const Network *network);
  void operator()(const Pin *pin) override;

protected:
  Pin *drvr_pin_;
  PinSet &visited_drvrs_;
  int &drvr_count_;
  int &bidirect_count_;
  int &load_count_;
  const Network *network_;
};

FindNetDrvrLoadCounts::FindNetDrvrLoadCounts(Pin *drvr_pin,
                                             PinSet &visited_drvrs,
                                             int &drvr_count,
                                             int &bidirect_count,
                                             int &load_count,
                                             const Network *network) :
  drvr_pin_(drvr_pin),
  visited_drvrs_(visited_drvrs),
  drvr_count_(drvr_count),
  bidirect_count_(bidirect_count),
  load_count_(load_count),
  network_(network)
{
}

void
FindNetDrvrLoadCounts::operator()(const Pin *pin)
{
  if (network_->isDriver(pin)) {
    if (pin != drvr_pin_)
      visited_drvrs_.insert(pin);
    if (network_->direction(pin)->isBidirect())
      bidirect_count_++;
    else
      drvr_count_++;
  }
  if (network_->isLoad(pin))
    load_count_++;
}

void
Graph::makePinVertices(const Instance *inst)
{
  InstancePinIterator *pin_iter = network_->pinIterator(inst);
  while (pin_iter->hasNext()) {
    Pin *pin = pin_iter->next();
    makePinVertices(pin);
  }
  delete pin_iter;
}

// Make edges corresponding to library timing arcs.
void
Graph::makeInstanceEdges(const Instance *inst)
{
  LibertyCell *cell = network_->libertyCell(inst);
  if (cell)
    makePortInstanceEdges(inst, cell, nullptr);
}

void
Graph::makePinInstanceEdges(const Pin *pin)
{
  const Instance *inst = network_->instance(pin);
  if (inst) {
    LibertyCell *cell = network_->libertyCell(inst);
    if (cell) {
      LibertyPort *port = network_->libertyPort(pin);
      makePortInstanceEdges(inst, cell, port);
    }
  }
}

void
Graph::makePortInstanceEdges(const Instance *inst,
                             LibertyCell *cell,
                             LibertyPort *from_to_port)
{
  for (TimingArcSet *arc_set : cell->timingArcSets()) {
    LibertyPort *from_port = arc_set->from();
    LibertyPort *to_port = arc_set->to();
    if ((from_to_port == nullptr
         || from_port == from_to_port
         || to_port == from_to_port)
        && from_port) {
      Pin *from_pin = network_->findPin(inst, from_port);
      Pin *to_pin = network_->findPin(inst, to_port);
      if (from_pin && to_pin) {
        Vertex *from_vertex, *from_bidirect_drvr_vertex;
        Vertex *to_vertex, *to_bidirect_drvr_vertex;
        pinVertices(from_pin, from_vertex, from_bidirect_drvr_vertex);
        pinVertices(to_pin, to_vertex, to_bidirect_drvr_vertex);
        // From pin and/or to pin can be bidirect.
        //  For combinational arcs edge is to driver.
        //  For timing checks edge is to load.
        // Vertices can be missing from the graph if the pins
        // are power or ground.
        if (from_vertex) {
          const TimingRole *role = arc_set->role();
          bool is_check = role->isTimingCheckBetween();
          if (to_bidirect_drvr_vertex && !is_check)
            makeEdge(from_vertex, to_bidirect_drvr_vertex, arc_set);
          else if (to_vertex) {
            makeEdge(from_vertex, to_vertex, arc_set);
            if (is_check) {
              to_vertex->setHasChecks(true);
              from_vertex->setIsCheckClk(true);
            }
          }
          if (from_bidirect_drvr_vertex && to_vertex) {
            // Internal path from bidirect output back into the
            // instance.
            Edge *edge = makeEdge(from_bidirect_drvr_vertex, to_vertex,
                                  arc_set);
            edge->setIsBidirectInstPath(true);
          }
        }
      }
    }
  }
}

void
Graph::makeWireEdges()
{
  PinSet visited_drvrs(network_);
  LeafInstanceIterator *inst_iter = network_->leafInstanceIterator();
  while (inst_iter->hasNext()) {
    Instance *inst = inst_iter->next();
    makeInstDrvrWireEdges(inst, visited_drvrs);
  }
  delete inst_iter;
  makeInstDrvrWireEdges(network_->topInstance(), visited_drvrs);
}

void
Graph::makeInstDrvrWireEdges(const Instance *inst,
                             PinSet &visited_drvrs)
{
  InstancePinIterator *pin_iter = network_->pinIterator(inst);
  while (pin_iter->hasNext()) {
    Pin *pin = pin_iter->next();
    if (network_->isDriver(pin)
        && !visited_drvrs.contains(pin))
      makeWireEdgesFromPin(pin, visited_drvrs);
    if (network_->isTopInstance(inst)
        && network_->direction(pin)->isBidirect()) {
      Vertex *bidir_load, *bidir_drvr;
      pinVertices(pin, bidir_load, bidir_drvr);
      Edge *edge = makeEdge(bidir_load, bidir_drvr, TimingArcSet::wireTimingArcSet());
      edge->setIsBidirectPortPath(true);
    }
  }
  delete pin_iter;
}

void
Graph::makeWireEdgesFromPin(const Pin *drvr_pin)
{
  PinSeq loads, drvrs;
  PinSet visited_drvrs(network_);
  FindNetDrvrLoads visitor(drvr_pin, visited_drvrs, loads, drvrs, network_);
  network_->visitConnectedPins(drvr_pin, visitor);

  for (auto load_pin : loads) {
    if (drvr_pin != load_pin)
      makeWireEdge(drvr_pin, load_pin);
  }
}

void
Graph::makeWireEdgesFromPin(const Pin *drvr_pin,
                            PinSet &visited_drvrs)
{
  // Find all drivers and loads on the net to avoid N*M run time
  // for large fanin/fanout nets.
  PinSeq drvrs, loads;
  FindNetDrvrLoads visitor(drvr_pin, visited_drvrs, loads, drvrs, network_);
  network_->visitConnectedPins(drvr_pin, visitor);

  if (isIsolatedNet(drvrs, loads)) {
    for (auto drvr_pin : drvrs) {
      visited_drvrs.insert(drvr_pin);
      debugPrint(debug_, "graph", 1, "ignoring isolated driver {}",
                 network_->pathName(drvr_pin));
    }
    return;
  }

  for (auto drvr_pin : drvrs) {
    for (auto load_pin : loads) {
      if (drvr_pin != load_pin)
        makeWireEdge(drvr_pin, load_pin);
    }
  }
}

// Check for nets with bidirect drivers that have no fanin or
// fanout. One example of these nets are bidirect pad ring pins
// are connected together but have no function but are marked
// as signal nets.
// These nets tickle N^2 behaviors that have no function.
bool
Graph::isIsolatedNet(PinSeq &drvrs,
                     PinSeq &loads) const
{
  if (drvrs.size() < 10)
    return false;
  // Check that all drivers have no fanin.
  for (auto drvr_pin : drvrs) {
    Vertex *drvr_vertex = pinDrvrVertex(drvr_pin);
    if (network_->isTopLevelPort(drvr_pin)
        || drvr_vertex->hasFanin())
      return false;
  }
  // Check for fanout on the load pins.
  for (auto load_pin : loads) {
    Vertex *load_vertex = pinLoadVertex(load_pin);
    if (load_vertex->hasFanout()
        || load_vertex->hasChecks()) {
      return false;
    }
  }
  return true;
}

void
Graph::makeWireEdgesToPin(const Pin *to_pin)
{
  PinSet *drvrs = network_->drivers(to_pin);
  if (drvrs) {
    for (auto drvr : *drvrs) {
      if (drvr != to_pin)
        makeWireEdge(drvr, to_pin);
    }
  }
}

class MakeEdgesThruHierPin : public HierPinThruVisitor
{
public:
  MakeEdgesThruHierPin(Graph *graph);
  void visit(const Pin *drvr,
             const Pin *load) override;

private:
  Graph *graph_;
};

MakeEdgesThruHierPin::MakeEdgesThruHierPin(Graph *graph) :
  HierPinThruVisitor(),
  graph_(graph)
{
}

void
MakeEdgesThruHierPin::visit(const Pin *drvr,
                            const Pin *load)
{
  graph_->makeWireEdge(drvr, load);
}

void
Graph::makeWireEdgesThruPin(const Pin *hpin)
{
  MakeEdgesThruHierPin visitor(this);
  visitDrvrLoadsThruHierPin(hpin, network_, &visitor);
}

void
Graph::makeWireEdge(const Pin *from_pin,
                    const Pin *to_pin)
{
  TimingArcSet *arc_set = TimingArcSet::wireTimingArcSet();
  Vertex *from_vertex, *from_bidirect_drvr_vertex;
  pinVertices(from_pin, from_vertex, from_bidirect_drvr_vertex);
  Vertex *to_vertex = pinLoadVertex(to_pin);
  if (from_vertex && to_vertex) {
    // From and/or to can be bidirect, but edge is always from driver to load.
    if (from_bidirect_drvr_vertex)
      makeEdge(from_bidirect_drvr_vertex, to_vertex, arc_set);
    else
      makeEdge(from_vertex, to_vertex, arc_set);
  }
}

////////////////////////////////////////////////////////////////

Vertex *
Graph::vertex(VertexId vertex_id) const
{
  return vertices_->pointer(vertex_id);
}

VertexId
Graph::id(const Vertex *vertex) const
{
  return vertices_->objectId(vertex);
}

void
Graph::makePinVertices(Pin *pin)
{
  Vertex *vertex, *bidir_drvr_vertex;
  makePinVertices(pin, vertex, bidir_drvr_vertex);
}

void
Graph::makePinVertices(Pin *pin,
                       Vertex *&vertex,
                       Vertex *&bidir_drvr_vertex)
{
  vertex = nullptr;
  bidir_drvr_vertex = nullptr;
  PortDirection *dir = network_->direction(pin);
  if (!dir->isPowerGround()) {
    bool is_reg_clk = network_->isRegClkPin(pin);
    vertex = makeVertex(pin, false, is_reg_clk);
    network_->setVertexId(pin, id(vertex));
    if (dir->isBidirect()) {
      bidir_drvr_vertex = makeVertex(pin, true, is_reg_clk);
      pin_bidirect_drvr_vertex_map_[pin] = bidir_drvr_vertex;
    }
  }
}

Vertex *
Graph::makeVertex(Pin *pin,
                  bool is_bidirect_drvr,
                  bool is_reg_clk)
{
  Vertex *vertex = vertices_->make();
  vertex->init(pin, is_bidirect_drvr, is_reg_clk);
  initSlews(vertex);
  if (is_reg_clk)
    reg_clk_vertices_.insert(vertex);
  return vertex;
}

void
Graph::pinVertices(const Pin *pin,
                   // Return values.
                   Vertex *&vertex,
                   Vertex *&bidirect_drvr_vertex)  const
{
  vertex = Graph::vertex(network_->vertexId(pin));
  if (network_->direction(pin)->isBidirect())
    bidirect_drvr_vertex = findKey(pin_bidirect_drvr_vertex_map_, pin);
  else
    bidirect_drvr_vertex = nullptr;
}

Vertex *
Graph::pinDrvrVertex(const Pin *pin) const
{
  if (network_->direction(pin)->isBidirect())
    return findKey(pin_bidirect_drvr_vertex_map_, pin);
  else
    return Graph::vertex(network_->vertexId(pin));
}

Vertex *
Graph::pinLoadVertex(const Pin *pin) const
{
  return vertex(network_->vertexId(pin));
}

void
Graph::deleteVertex(Vertex *vertex)
{
  if (vertex->isRegClk())
    reg_clk_vertices_.erase(vertex);
  Pin *pin = vertex->pin_;
  if (vertex->isBidirectDriver())
    pin_bidirect_drvr_vertex_map_.erase(pin_bidirect_drvr_vertex_map_
                                        .find(pin));
  else
    network_->setVertexId(pin, vertex_id_null);
  // Delete edges to vertex.
  EdgeId edge_id, next_id;
  for (edge_id = vertex->in_edges_; edge_id; edge_id = next_id) {
    Edge *edge = Graph::edge(edge_id);
    next_id = edge->vertex_in_next_;
    deleteOutEdge(edge->from(this), edge);
    edge->clear();
    edges_->destroy(edge);
  }
  // Delete edges from vertex.
  for (edge_id = vertex->out_edges_; edge_id; edge_id = next_id) {
    Edge *edge = Graph::edge(edge_id);
    next_id = edge->vertex_out_next_;
    deleteInEdge(edge->to(this), edge);
    edge->clear();
    edges_->destroy(edge);
  }
  vertex->clear();
  vertices_->destroy(vertex);
}

bool
Graph::hasFaninOne(Vertex *vertex) const
{
  return vertex->in_edges_
    && edge(vertex->in_edges_)->vertex_in_next_ == 0;
}

void
Graph::deleteInEdge(Vertex *vertex,
                    Edge *edge)
{
  EdgeId edge_id = id(edge);
  EdgeId prev = 0;
  for (EdgeId i = vertex->in_edges_;
       i && i != edge_id;
       i = Graph::edge(i)->vertex_in_next_)
    prev = i;
  if (prev)
    Graph::edge(prev)->vertex_in_next_ = edge->vertex_in_next_;
  else
    vertex->in_edges_ = edge->vertex_in_next_;
}

void
Graph::deleteOutEdge(Vertex *vertex,
                     Edge *edge)
{
  EdgeId next = edge->vertex_out_next_;
  EdgeId prev = edge->vertex_out_prev_;
  if (prev)
    Graph::edge(prev)->vertex_out_next_ = next;
  else
    vertex->out_edges_ = next;
  if (next)
    Graph::edge(next)->vertex_out_prev_ = prev;
}

void
Graph::gateEdgeArc(const Pin *in_pin,
                   const RiseFall *in_rf,
                   const Pin *drvr_pin,
                   const RiseFall *drvr_rf,
                   // Return values.
                   Edge *&edge,
                   const TimingArc *&arc) const
{
  Vertex *in_vertex = pinLoadVertex(in_pin);
  Vertex *drvr_vertex = pinDrvrVertex(drvr_pin);
  // Iterate over load drivers to avoid driver fanout^2.
  VertexInEdgeIterator edge_iter(drvr_vertex, this);
  while (edge_iter.hasNext()) {
    Edge *edge1 = edge_iter.next();
    if (edge1->from(this) == in_vertex) {
      TimingArcSet *arc_set = edge1->timingArcSet();
      for (TimingArc *arc1 : arc_set->arcs()) {
        if (arc1->fromEdge()->asRiseFall() == in_rf
            && arc1->toEdge()->asRiseFall() == drvr_rf) {
          edge = edge1;
          arc = arc1;
          return;
        }
      }
    }
  }
  edge = nullptr;
  arc = nullptr;
}

////////////////////////////////////////////////////////////////

void
Graph::visitFanouts(Vertex *vertex,
                    SearchPred *pred,
                    const VertexFn &fn)
{
  if (pred->searchFrom(vertex)) {
    VertexOutEdgeIterator edge_iter(vertex, graph_);
    while (edge_iter.hasNext()) {
      Edge *edge = edge_iter.next();
      Vertex *to_vertex = this->vertex(edge->to_);
      if (pred->searchThru(edge)
          && pred->searchTo(to_vertex))
        fn(to_vertex);
    }
  }
}

void
Graph::visitFanoutEdges(Vertex *vertex,
                        SearchPred *pred,
                        const EdgeFn &fn)
{
  if (pred->searchFrom(vertex)) {
    VertexOutEdgeIterator edge_iter(vertex, graph_);
    while (edge_iter.hasNext()) {
      Edge *edge = edge_iter.next();
      Vertex *to_vertex = this->vertex(edge->to_);
      if (pred->searchThru(edge)
          && pred->searchTo(to_vertex))
        fn(edge, to_vertex);
    }
  }
}

void
Graph::visitFanins(Vertex *vertex,
                   SearchPred *pred,
                   const VertexFn &fn)
{
  if (pred->searchFrom(vertex)) {
    VertexInEdgeIterator edge_iter(vertex, graph_);
    while (edge_iter.hasNext()) {
      Edge *edge = edge_iter.next();
      Vertex *from_vertex = this->vertex(edge->from_);
      if (pred->searchThru(edge)
          && pred->searchFrom(from_vertex))
        fn(from_vertex);
    }
  }
}

void
Graph::visitFaninEdges(Vertex *vertex,
                       SearchPred *pred,
                       const EdgeFn &fn)
{
  if (pred->searchFrom(vertex)) {
    VertexInEdgeIterator edge_iter(vertex, graph_);
    while (edge_iter.hasNext()) {
      Edge *edge = edge_iter.next();
      Vertex *from_vertex = this->vertex(edge->from_);
      if (pred->searchThru(edge)
          && pred->searchFrom(from_vertex))
        fn(edge, from_vertex);
    }
  }
}

////////////////////////////////////////////////////////////////

Slew
Graph::slew(const Vertex *vertex,
            const RiseFall *rf,
            DcalcAPIndex ap_index)
{
  size_t slew_index = ap_index * RiseFall::index_count + rf->index();
  const float *slews_flt = vertex->slewsFloat();
  if (variables_->pocvEnabled()) {
    const Slew *slews = reinterpret_cast<const Slew*>(slews_flt);
    return slews[slew_index];
  }
  else
    return slews_flt[slew_index];
}

Slew
Graph::slew(const Vertex *vertex,
            size_t index)
{
  const float *slews_flt = vertex->slewsFloat();
  if (variables_->pocvEnabled()) {
    const Slew *slews = reinterpret_cast<const Slew*>(slews_flt);
    return slews[index];
  }
  else
    return slews_flt[index];
}

void
Graph::setSlew(Vertex *vertex,
               const RiseFall *rf,
               DcalcAPIndex ap_index,
               const Slew &slew)
{
  size_t slew_index = ap_index * RiseFall::index_count + rf->index();
  if (variables_->pocvEnabled()) {
    Slew *slews = vertex->slews();
    slews[slew_index] = slew;
  }
  else {
    float *slews_flt = vertex->slewsFloat();
    slews_flt[slew_index] = slew.mean();
  }
}

////////////////////////////////////////////////////////////////

Edge *
Graph::edge(EdgeId edge_id) const
{
  return edges_->pointer(edge_id);
}

EdgeId
Graph::id(const Edge *edge) const
{
  return edges_->objectId(edge);
}

Edge *
Graph::makeEdge(Vertex *from,
                Vertex *to,
                TimingArcSet *arc_set)
{
  Edge *edge = edges_->make();
  edge->init(id(from), id(to), arc_set);
  // Add out edge to from vertex.
  EdgeId next = from->out_edges_;
  edge->vertex_out_next_ = next;
  edge->vertex_out_prev_ = edge_id_null;
  EdgeId edge_id = edges_->objectId(edge);
  if (next)
    Graph::edge(next)->vertex_out_prev_ = edge_id;
  from->out_edges_ = edge_id;

  // Add in edge to to vertex.
  edge->vertex_in_next_ = to->in_edges_;
  to->in_edges_ = edge_id;

  initArcDelays(edge);
  return edge;
}

void
Graph::deleteEdge(Edge *edge)
{
  Vertex *from = edge->from(this);
  Vertex *to = edge->to(this);
  deleteOutEdge(from, edge);
  deleteInEdge(to, edge);
  edge->clear();
  edges_->destroy(edge);
}

ArcDelay
Graph::arcDelay(const Edge *edge,
                const TimingArc *arc,
                DcalcAPIndex ap_index) const
{
  size_t index = arc->index() * ap_count_ + ap_index;
  if (variables_->pocvEnabled()) {
    const ArcDelay *delays = reinterpret_cast<const ArcDelay*>(edge->arcDelays());
    return delays[index];
  }
  else {
    const float *delays = edge->arcDelays();
    return delays[index];
  }
}

void
Graph::setArcDelay(Edge *edge,
                   const TimingArc *arc,
                   DcalcAPIndex ap_index,
                   const ArcDelay &delay)
{
  size_t index = arc->index() * ap_count_ + ap_index;
  if (variables_->pocvEnabled()) {
    ArcDelay *delays = reinterpret_cast<ArcDelay*>(edge->arcDelays());
    delays[index] = delay;
  }
  else {
    float *delays = edge->arcDelays();
    delays[index] = delay.mean();
  }
}

ArcDelay
Graph::wireArcDelay(const Edge *edge,
                    const RiseFall *rf,
                    DcalcAPIndex ap_index)
{
  size_t index = rf->index() * ap_count_ + ap_index;
  if (variables_->pocvEnabled()) {
    const ArcDelay *delays = reinterpret_cast<const ArcDelay*>(edge->arcDelays());
    return delays[index];
  }
  else {
    const float *delays = edge->arcDelays();
    return delays[index];
  }
}

void
Graph::setWireArcDelay(Edge *edge,
                       const RiseFall *rf,
                       DcalcAPIndex ap_index,
                       const ArcDelay &delay)
{
  size_t index = rf->index() * ap_count_ + ap_index;
  if (variables_->pocvEnabled()) {
    ArcDelay *delays = reinterpret_cast<ArcDelay*>(edge->arcDelays());
    delays[index] = delay;
  }
  else {
    float *delays = edge->arcDelays();
    delays[index] = delay.mean();
  }
}

////////////////////////////////////////////////////////////////

bool
Graph::arcDelayAnnotated(const Edge *edge,
                         const TimingArc *arc,
                         DcalcAPIndex ap_index) const
{
  return edge->arcDelayAnnotated(arc, ap_index, ap_count_);
}

void
Graph::setArcDelayAnnotated(Edge *edge,
                            const TimingArc *arc,
                            DcalcAPIndex ap_index,
                            bool annotated)
{
  edge->setArcDelayAnnotated(arc, ap_index, ap_count_, annotated);
}

bool
Graph::wireDelayAnnotated(const Edge *edge,
                          const RiseFall *rf,
                          DcalcAPIndex ap_index) const
{
  int arc_index = TimingArcSet::wireArcIndex(rf);
  TimingArc *arc = TimingArcSet::wireTimingArcSet()->findTimingArc(arc_index);
  return edge->arcDelayAnnotated(arc, ap_index, ap_count_);
}

void
Graph::setWireDelayAnnotated(Edge *edge,
                             const RiseFall *rf,
                             DcalcAPIndex ap_index,
                             bool annotated)
{
  int arc_index = TimingArcSet::wireArcIndex(rf);
  TimingArc *arc = TimingArcSet::wireTimingArcSet()->findTimingArc(arc_index);
  edge->setArcDelayAnnotated(arc, ap_index, ap_count_, annotated);
}

void
Graph::removeDelayAnnotated(Edge *edge)
{
  edge->removeDelayAnnotated();
}

////////////////////////////////////////////////////////////////

void
Graph::delayCountChanged()
{
  ap_count_ = dcalcAnalysisPtCount();
  // Discard any existing delays.
  removePeriodCheckAnnotations();
  initSlews();
}

void
Graph::initSlews()
{
  VertexIterator vertex_iter(graph_);
  while (vertex_iter.hasNext()) {
    Vertex *vertex = vertex_iter.next();
    initSlews(vertex);

    VertexOutEdgeIterator edge_iter(vertex, graph_);
    while (edge_iter.hasNext()) {
      Edge *edge = edge_iter.next();
      initArcDelays(edge);
    }
  }
}

void
Graph::initSlews(Vertex *vertex)
{
  size_t slew_count = slewCount();
  if (variables_->pocvEnabled()) {
    float *slews = reinterpret_cast<float*>(new Slew[slew_count]{});
    vertex->setSlews(slews);
  }
  else {
    float *slews = new float[slew_count]{};
    vertex->setSlews(slews);
  }
}

size_t
Graph::slewCount()
{
  return RiseFall::index_count * ap_count_;
}

void
Graph::initArcDelays(Edge *edge)
{
  size_t arc_count = edge->timingArcSet()->arcCount();
  size_t delay_count = arc_count * ap_count_;
  if (variables_->pocvEnabled()) {
    float *delays = reinterpret_cast<float*>(new ArcDelay[delay_count]{});
    edge->setArcDelays(delays);
  }
  else {
    float *delays = new float[delay_count]{};
    edge->setArcDelays(delays);
  }
}

////////////////////////////////////////////////////////////////

void
Graph::minPulseWidthArc(Vertex *vertex,
                        // high = rise, low = fall
                        const RiseFall *hi_low,
                        // Return values.
                        Edge *&edge,
                        TimingArc *&arc)
{
  VertexOutEdgeIterator edge_iter(vertex, this);
  while (edge_iter.hasNext()) {
    edge = edge_iter.next();
    TimingArcSet *arc_set = edge->timingArcSet();
    if (arc_set->role() == TimingRole::width()) {
      for (TimingArc *arc1 : arc_set->arcs()) {
        if (arc1->fromEdge()->asRiseFall() == hi_low) {
          arc = arc1;
          return;
        }
      }
    }
  }
  edge = nullptr;
  arc = nullptr;
}

void
Graph::minPeriodArc(Vertex *vertex,
                    const RiseFall *rf,
                    // Return values.
                    Edge *&edge,
                    TimingArc *&arc)
{
  VertexOutEdgeIterator edge_iter(vertex, this);
  while (edge_iter.hasNext()) {
    edge = edge_iter.next();
    TimingArcSet *arc_set = edge->timingArcSet();
    if (arc_set->role() == TimingRole::period()) {
      for (TimingArc *arc1 : arc_set->arcs()) {
        if (arc1->fromEdge()->asRiseFall() == rf) {
          arc = arc1;
          return;
        }
      }
    }
  }
  edge = nullptr;
  arc = nullptr;
}

////////////////////////////////////////////////////////////////

void
Graph::periodCheckAnnotation(const Pin *pin,
                             DcalcAPIndex ap_index,
                             // Return values.
                             float &period,
                             bool &exists)
{
  exists = false;
  float *periods = findKey(period_check_annotations_, pin);
  if (periods) {
    period = periods[ap_index];
    if (period >= 0.0)
      exists = true;
  }
}

void
Graph::setPeriodCheckAnnotation(const Pin *pin,
                                DcalcAPIndex ap_index,
                                float period)
{
  float *periods = findKey(period_check_annotations_, pin);
  if (periods == nullptr) {
    periods = new float[ap_count_];
    // Use negative (illegal) period values to indicate unannotated checks.
    for (int i = 0; i < ap_count_; i++)
      periods[i] = -1;
    period_check_annotations_[pin] = periods;
  }
  periods[ap_index] = period;
}

void
Graph::removePeriodCheckAnnotations()
{
  for (auto& [pin, periods] : period_check_annotations_)
    delete [] periods;
  period_check_annotations_.clear();
}

void
Graph::removeDelaySlewAnnotations()
{
  VertexIterator vertex_iter(graph_);
  while (vertex_iter.hasNext()) {
    Vertex *vertex = vertex_iter.next();
    VertexOutEdgeIterator edge_iter(vertex, graph_);
    while (edge_iter.hasNext()) {
      Edge *edge = edge_iter.next();
      removeDelayAnnotated(edge);
    }
    vertex->removeSlewAnnotated();
  }
  removePeriodCheckAnnotations();
}

////////////////////////////////////////////////////////////////
//
// Vertex
//
////////////////////////////////////////////////////////////////

Vertex::Vertex()
{
  init(nullptr, false, false);
  object_idx_ = object_idx_null;
}

void
Vertex::init(Pin *pin,
             bool is_bidirect_drvr,
             bool is_reg_clk)
{
  pin_ = pin;
  in_edges_ = edge_id_null;
  out_edges_ = edge_id_null;
  slews_ = nullptr;
  paths_ = nullptr;
  tag_group_index_ = tag_group_index_max;
  is_bidirect_drvr_ = is_bidirect_drvr;
  is_reg_clk_ = is_reg_clk;
  has_checks_ = false;
  is_check_clk_ = false;
  has_downstream_clk_pin_ = false;
  visited1_ = false;
  visited2_ = false;
  has_sim_value_ = false;
  level_ = 0;
  slew_annotated_ = false;
  bfs_in_queue_ = 0;
  bfs_predecessor_changed_ = false;
}

Vertex::~Vertex()
{
  clear();
}

void
Vertex::clear()
{
  delete [] slews_;
  slews_ = nullptr;
  delete [] paths_;
  paths_ = nullptr;
}

void
Vertex::setObjectIdx(ObjectIdx idx)
{
  object_idx_ = idx;
}

std::string
Vertex::to_string(const StaState *sta) const
{
  const Network *network = sta->sdcNetwork();
  if (network->direction(pin_)->isBidirect()) {
    std::string str(network->pathName(pin_));
    str += ' ';
    str += is_bidirect_drvr_ ? "driver" : "load";
    return str;
  }
  else
    return network->pathName(pin_);
}

std::string
Vertex::name(const Network *network) const
{
  return to_string(network);
}

bool
Vertex::isDriver(const Network *network) const
{
  PortDirection *dir = network->direction(pin_);
  bool top_level_port = network->isTopLevelPort(pin_);
  return ((top_level_port
           && (dir->isInput()
               || (dir->isBidirect()
                   && is_bidirect_drvr_)))
          || (!top_level_port
              && (dir->isOutput()
                  || dir->isTristate()
                  || (dir->isBidirect()
                      && is_bidirect_drvr_)
                  || dir->isInternal())));
}

bool
Vertex::isLoad(const Network *network) const
{
  PortDirection *dir = network->direction(pin_);
  bool top_level_port = network->isTopLevelPort(pin_);
  return ((top_level_port
           && (dir->isOutput()
               || (dir->isBidirect()
                   && !is_bidirect_drvr_)))
          || (!top_level_port
              && (dir->isInput()
                  || dir->isTristate()
                  || (dir->isBidirect()
                      && !is_bidirect_drvr_)
                  || dir->isInternal())));
}

void
Vertex::setLevel(Level level)
{
  level_ = level;
}

void
Vertex::setVisited(bool visited)
{
  visited1_ = visited;
}

void
Vertex::setVisited2(bool visited)
{
  visited2_ = visited;
}

void
Vertex::setSlews(float *slews)
{
  delete [] slews_;
  slews_ = slews;
}

void
Vertex::setHasSimValue(bool has_sim)
{
  has_sim_value_ = has_sim;
}

bool
Vertex::slewAnnotated(const RiseFall *rf,
                      const MinMax *min_max) const
{
  int index = min_max->index() * RiseFall::index_count+ rf->index();
  return ((1 << index) & slew_annotated_) != 0;
}

bool
Vertex::slewAnnotated() const
{
  return slew_annotated_ != 0;
}

void
Vertex::setSlewAnnotated(bool annotated,
                         const RiseFall *rf,
                         DcalcAPIndex ap_index)
{
  // Track rise/fall/min/max annotations separately, but after that
  // only rise/fall.
  if (ap_index > 1)
    ap_index = 0;
  int index = ap_index * RiseFall::index_count + rf->index();
  if (annotated)
    slew_annotated_ |= (1 << index);
  else
    slew_annotated_ &= ~(1 << index);
}

void
Vertex::removeSlewAnnotated()
{
  slew_annotated_ = 0;
}

TagGroupIndex
Vertex::tagGroupIndex() const
{
  return tag_group_index_;
}

void
Vertex::setTagGroupIndex(TagGroupIndex tag_index)
{
  tag_group_index_ = tag_index;
}

Path *
Vertex::makePaths(uint32_t count)
{
  delete [] paths_;
  Path *paths = new Path[count];
  paths_ = paths;
  return paths;
}

void
Vertex::setPaths(Path *paths)
{
  delete [] paths_;
  paths_ = paths;
}

void
Vertex::deletePaths()
{
  delete [] paths_;
  paths_ = nullptr;
  tag_group_index_ = tag_group_index_max;
}

bool
Vertex::hasFanin() const
{
  return in_edges_ != edge_id_null;
}

bool
Vertex::hasFanout() const
{
  return out_edges_ != edge_id_null;
}

void
Vertex::setHasChecks(bool has_checks)
{
  has_checks_ = has_checks;
}

void
Vertex::setIsCheckClk(bool is_check_clk)
{
  is_check_clk_ = is_check_clk;
}

void
Vertex::setHasDownstreamClkPin(bool has_clk_pin)
{
  has_downstream_clk_pin_ = has_clk_pin;
}

bool
Vertex::bfsInQueue(BfsIndex index) const
{
  return (bfs_in_queue_ >> static_cast<unsigned>(index)) & 1;
}

void
Vertex::setBfsInQueue(BfsIndex index,
                      bool value)
{
  if (value)
    bfs_in_queue_ |= 1 << static_cast<unsigned>(index);
  else
    bfs_in_queue_ &= ~(1 << static_cast<unsigned>(index));
}

void
Vertex::setBfsPredecessorChanged(bool changed)
{
  bfs_predecessor_changed_ = changed;
}

////////////////////////////////////////////////////////////////
//
// Edge
//
////////////////////////////////////////////////////////////////

Edge::Edge()
{
  init(0, 0, nullptr);
  object_idx_ = object_idx_null;
}

void
Edge::init(VertexId from,
           VertexId to,
           TimingArcSet *arc_set)
{
  arc_set_ = arc_set;
  arc_delays_ = nullptr;
  arc_delay_annotated_is_bits_ = true;
  arc_delay_annotated_.bits_ = 0;
  from_ = from;
  to_ = to;
  vertex_in_next_ = edge_id_null;
  vertex_out_next_ = edge_id_null;
  vertex_out_prev_ = edge_id_null;
  delay_annotation_is_incremental_ = false;
  is_bidirect_inst_path_ = false;
  is_bidirect_net_path_ = false;
  is_bidirect_port_path_ = false;
  is_disabled_loop_ = false;
  has_sim_sense_ = false;
  has_disabled_cond_ = false;
}

Edge::~Edge()
{
  clear();
}

void
Edge::clear()
{
  delete [] arc_delays_;
  arc_delays_ = nullptr;
  if (!arc_delay_annotated_is_bits_)
    delete arc_delay_annotated_.seq_;
  arc_delay_annotated_is_bits_ = true;
  arc_delay_annotated_.seq_ = nullptr;
}

void
Edge::setObjectIdx(ObjectIdx idx)
{
  object_idx_ = idx;
}

std::string
Edge::to_string(const StaState *sta) const
{
  const Graph *graph = sta->graph();
  std::string str = from(graph)->to_string(sta);
  str += " -> ";
  str += to(graph)->to_string(sta);
  str += " ";
  str += role()->to_string();
  FuncExpr *when = arc_set_->cond();
  if (when) {
    str += " ";
    str += when->to_string();
  }
  return str;
}

void
Edge::setTimingArcSet(TimingArcSet *set)
{
  arc_set_ = set;
}

void
Edge::setArcDelays(float *delays)
{
  delete [] arc_delays_;
  arc_delays_ = delays;
}

bool
Edge::arcDelayAnnotated(const TimingArc *arc,
                        DcalcAPIndex ap_index,
                        DcalcAPIndex ap_count) const
{
  size_t index = arc->index() * ap_count + ap_index;
  if (arc_delay_annotated_is_bits_)
    return arc_delay_annotated_.bits_ & arcDelayAnnotateBit(index);
  else
    return (*arc_delay_annotated_.seq_)[index];
}

void
Edge::setArcDelayAnnotated(const TimingArc *arc,
                           DcalcAPIndex ap_index,
                           DcalcAPIndex ap_count,
                           bool annotated)
{
  size_t index = arc->index() * ap_count + ap_index;
  if (index > sizeof(uintptr_t) * 8
      && arc_delay_annotated_is_bits_) {
    arc_delay_annotated_is_bits_ = false;
    size_t bit_count = ap_count * RiseFall::index_count * 2;
    arc_delay_annotated_.seq_ = new std::vector<bool>(bit_count);
  }
  if (arc_delay_annotated_is_bits_) {
    if (annotated)
      arc_delay_annotated_.bits_ |= arcDelayAnnotateBit(index);
    else
      arc_delay_annotated_.bits_ &= ~arcDelayAnnotateBit(index);
  }
  else
    (*arc_delay_annotated_.seq_)[index] = annotated;
}

void
Edge::removeDelayAnnotated()
{
  delay_annotation_is_incremental_ = false;
  if (arc_delay_annotated_is_bits_)
    arc_delay_annotated_.bits_ = 0;
  else {
    delete arc_delay_annotated_.seq_;
    arc_delay_annotated_.seq_ = nullptr;
  }
}

void
Edge::setDelayAnnotationIsIncremental(bool is_incr)
{
  delay_annotation_is_incremental_ = is_incr;
}

uintptr_t
Edge::arcDelayAnnotateBit(size_t index)
{
  return static_cast<uintptr_t>(1) << index;
}

const TimingRole *
Edge::role() const
{
  return arc_set_->role();
}

bool
Edge::isWire() const
{
  return arc_set_->role()->isWire();
}
 
TimingSense
Edge::sense() const
{
  return arc_set_->sense();
}

void
Edge::setIsDisabledLoop(bool disabled)
{
  is_disabled_loop_ = disabled;
}

void
Edge::setIsBidirectInstPath(bool is_bidir)
{
  is_bidirect_inst_path_ = is_bidir;
}

void
Edge::setIsBidirectNetPath(bool is_bidir)
{
  is_bidirect_net_path_ = is_bidir;
}

void
Edge::setIsBidirectPortPath(bool is_bidir)
{
  is_bidirect_port_path_ = is_bidir;
}

void
Edge::setHasSimSense(bool has_sense)
{
  has_sim_sense_ = has_sense;
}

void
Edge::setHasDisabledCond(bool has_disabled)
{
  has_disabled_cond_ = has_disabled;
}

////////////////////////////////////////////////////////////////

VertexIterator::VertexIterator(Graph *graph) :
  graph_(graph),
  network_(graph->network()),
  top_inst_(network_->topInstance()),
  inst_iter_(network_->leafInstanceIterator())
{
  if (inst_iter_)
    findNext();
}

Vertex *
VertexIterator::next()
{
  Vertex *next = nullptr;
  if (vertex_) {
    next = vertex_;
    vertex_ = nullptr;
  }
  else if (bidir_vertex_) {
    next = bidir_vertex_;
    bidir_vertex_ = nullptr;
  }
  if (bidir_vertex_ == nullptr)
    findNext();
  return next;
}

bool
VertexIterator::findNextPin()
{
  while (pin_iter_->hasNext()) {
    Pin *pin = pin_iter_->next();
    vertex_ = graph_->vertex(network_->vertexId(pin));
    bidir_vertex_ = network_->direction(pin)->isBidirect() 
      ? findKey(graph_->pin_bidirect_drvr_vertex_map_, pin)
      : nullptr;
    if (vertex_ || bidir_vertex_)
      return true;
  }
  delete pin_iter_;
  pin_iter_ = nullptr;
  return false;
}

void 
VertexIterator::findNext()
{
  while (inst_iter_) {
    if (pin_iter_
        && findNextPin())
      return;
    
    if (inst_iter_->hasNext()) {
      Instance *inst = inst_iter_->next();
      pin_iter_ = network_->pinIterator(inst);
    } else {
      delete inst_iter_;
      inst_iter_ = nullptr;
      if (top_inst_) {
        pin_iter_ = network_->pinIterator(top_inst_);
        top_inst_ = nullptr;
      }
    }
  }
  if (pin_iter_)
    findNextPin();
}

////////////////////////////////////////////////////////////////

VertexInEdgeIterator::VertexInEdgeIterator(Vertex *vertex,
                                           const Graph *graph) :
  next_(graph->edge(vertex->in_edges_)),
  graph_(graph)
{
}

VertexInEdgeIterator::VertexInEdgeIterator(VertexId vertex_id,
                                           const Graph *graph) :
  next_(graph->edge(graph->vertex(vertex_id)->in_edges_)),
  graph_(graph)
{
}

Edge *
VertexInEdgeIterator::next()
{
  Edge *next = next_;
  if (next_)
    next_ = graph_->edge(next_->vertex_in_next_);
  return next;
}

VertexOutEdgeIterator::VertexOutEdgeIterator(Vertex *vertex,
                                             const Graph *graph) :
  next_(graph->edge(vertex->out_edges_)),
  graph_(graph)
{
}

Edge *
VertexOutEdgeIterator::next()
{
  Edge *next = next_;
  if (next_)
    next_ = graph_->edge(next_->vertex_out_next_);
  return next;
}

////////////////////////////////////////////////////////////////

class FindEdgesThruHierPinVisitor : public HierPinThruVisitor
{
public:
  FindEdgesThruHierPinVisitor(EdgeSet &edges,
                              Graph *graph);
  void visit(const Pin *drvr,
             const Pin *load) override;
  
protected:
  EdgeSet &edges_;
  Graph *graph_;
};

FindEdgesThruHierPinVisitor::FindEdgesThruHierPinVisitor(EdgeSet &edges,
                                                         Graph *graph) :
  HierPinThruVisitor(),
  edges_(edges),
  graph_(graph)
{
}

void
FindEdgesThruHierPinVisitor::visit(const Pin *drvr,
                                   const Pin *load)
{
  Vertex *drvr_vertex = graph_->pinDrvrVertex(drvr);
  Vertex *load_vertex = graph_->pinLoadVertex(load);
  // Iterate over load drivers to avoid driver fanout^2.
  VertexInEdgeIterator edge_iter(load_vertex, graph_);
  while (edge_iter.hasNext()) {
    Edge *edge = edge_iter.next();
    if (edge->from(graph_) == drvr_vertex)
      edges_.insert(edge);
  }
}

EdgesThruHierPinIterator::EdgesThruHierPinIterator(const Pin *hpin,
                                                   Network *network,
                                                   Graph *graph)
{
  FindEdgesThruHierPinVisitor visitor(edges_, graph);
  visitDrvrLoadsThruHierPin(hpin, network, &visitor);
  edge_iter_ = edges_.begin();
}

bool
EdgesThruHierPinIterator::hasNext()
{
  return edge_iter_ != edges_.end();
}

Edge *
EdgesThruHierPinIterator::next()
{
  return *edge_iter_++;
}

////////////////////////////////////////////////////////////////

VertexIdLess::VertexIdLess(Graph *&graph) :
  graph_(graph)
{
}

bool
VertexIdLess::operator()(const Vertex *vertex1,
                         const Vertex *vertex2) const
{
  return graph_->id(vertex1) < graph_->id(vertex2);
}


} // namespace sta