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// OpenSTA, Static Timing Analyzer
// Copyright (c) 2019, 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/>.
#ifndef STA_LEVELIZE_H
#define STA_LEVELIZE_H
#include "DisallowCopyAssign.hh"
#include "StaState.hh"
#include "NetworkClass.hh"
#include "SdcClass.hh"
#include "GraphClass.hh"
namespace sta {
class SearchPred;
class LevelizeObserver;
class Levelize : public StaState
{
public:
explicit Levelize(StaState *sta);
virtual ~Levelize();
// Space between initially assigned levels that is filled in by
// incremental levelization. Set level space before levelization.
void setLevelSpace(Level space);
bool levelized() { return levels_valid_; }
void ensureLevelized();
void invalid();
// Levels downstream from vertex are invalid.
void invalidFrom(Vertex *vertex);
void relevelizeFrom(Vertex *vertex);
void deleteVertexBefore(Vertex *vertex);
void deleteEdgeBefore(Edge *edge);
int maxLevel() const { return max_level_; }
// Vertices with no fanin edges.
VertexSet &roots() { return roots_; }
bool isRoot(Vertex *vertex);
// Reset to virgin state.
void clear();
// Edge is disabled to break combinational loops.
bool isDisabledLoop(Edge *edge) const;
// Only valid when levels are valid.
GraphLoopSeq *loops() { return loops_; }
// Set the observer for level changes.
void setObserver(LevelizeObserver *observer);
protected:
void levelize();
void findRoots();
void sortRoots(VertexSeq &roots);
void levelizeFrom(VertexSeq &roots);
void visit(Vertex *vertex, Level level, Level level_space, EdgeSeq &path);
void levelizeCycles();
void relevelize();
void clearLoopEdges();
void deleteLoops();
void recordLoop(Edge *edge, EdgeSeq &path);
EdgeSeq *loopEdges(EdgeSeq &path, Edge *closing_edge);
void ensureLatchLevels();
void setLevel(Vertex *vertex,
Level level);
SearchPred *search_pred_;
bool levelized_;
bool levels_valid_;
Level max_level_;
Level level_space_;
VertexSet roots_;
VertexSet relevelize_from_;
GraphLoopSeq *loops_;
EdgeSet loop_edges_;
EdgeSet disabled_loop_edges_;
EdgeSet latch_d_to_q_edges_;
LevelizeObserver *observer_;
private:
DISALLOW_COPY_AND_ASSIGN(Levelize);
};
// Loops broken by levelization may not necessarily be combinational.
// For example, a register/latch output can feed back to a gated clock
// enable on the register/latch clock.
class GraphLoop
{
public:
explicit GraphLoop(EdgeSeq *edges);
~GraphLoop();
EdgeSeq *edges() { return edges_; }
bool isCombinational() const;
void report(Report *report,
Network *network,
Graph *graph) const;
private:
DISALLOW_COPY_AND_ASSIGN(GraphLoop);
EdgeSeq *edges_;
};
class LevelizeObserver
{
public:
LevelizeObserver() {}
virtual ~LevelizeObserver() {}
virtual void levelChangedBefore(Vertex *vertex) = 0;
private:
DISALLOW_COPY_AND_ASSIGN(LevelizeObserver);
};
} // namespace
#endif
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