Liberty equiv cells in LibertyCell instead of map

liberty/EquivCells.cc

@@ -30,12 +30,13 @@
 namespace sta {
 
 typedef UnorderedMap<unsigned, LibertyCellSeq*> LibertyCellHashMap;
-typedef Set<LibertyCellSeq*> LibertyCellSeqSet;
+typedef Set<LibertyCell*> LibertyCellSet;
 
-static LibertyCellEquivMap *
-findEquivCells1(const LibertyLibrary *library);
 static void
-sortCellEquivs(LibertyCellEquivMap *cell_equivs);
+findEquivCells1(const LibertyLibrary *library,
+		LibertyCellSet &cell_equivs);
+static void
+sortCellEquivs(LibertyCellSet &cell_equivs);
 static float
 cellDriveResistance(const LibertyCell *cell);
 
@@ -56,47 +57,24 @@ static bool
 equivCellSequentials(const LibertyCell *cell1,
 		     const LibertyCell *cell2);
 
-LibertyCellEquivMap *
+void
 findEquivCells(const LibertyLibrary *library)
 {
-  // Build a map from each cell in the library to a group (CellSeq) of
-  // cells with equivalent functionality.
-  LibertyCellEquivMap *cell_equivs = findEquivCells1(library);
+  LibertyCellSet cell_equivs;
+  findEquivCells1(library, cell_equivs);
   // Sort by drive strength.
   sortCellEquivs(cell_equivs);
-  return cell_equivs;
 }
 
-// Delete the LibertyCellEquivMap returned by makeEquivCellMap.
-void
-deleteEquivCellMap(LibertyCellEquivMap *equiv_map)
-{
-  // Multiple cells can point to the same cell sequence, so collect
-  // them into a set so the are only deleted once.
-  LibertyCellSeqSet cells_seqs;
-  LibertyCellEquivMap::Iterator equiv_iter(equiv_map);
-  while (equiv_iter.hasNext()) {
-    LibertyCellSeq *cells = equiv_iter.next();
-    cells_seqs.insert(cells);
-  }
-  LibertyCellSeqSet::Iterator cells_iter(cells_seqs);
-  while (cells_iter.hasNext()) {
-    LibertyCellSeq *cells = cells_iter.next();
-    delete cells;
-  }
-  delete equiv_map;
-}
-
-static LibertyCellEquivMap *
-findEquivCells1(const LibertyLibrary *library)
+static void
+findEquivCells1(const LibertyLibrary *library,
+		LibertyCellSet &cell_equivs)
 {
   LibertyCellHashMap cell_hash;
-  LibertyCellEquivMap *cell_equivs = new LibertyCellEquivMap;
   LibertyCellIterator cell_iter(library);
   while (cell_iter.hasNext()) {
     LibertyCell *cell = cell_iter.next();
     if (!cell->dontUse()) {
-      bool found_equiv = false;
       unsigned hash = hashCell(cell);
       // Use a comprehensive hash on cell properties to segregate
       // cells into groups of potential matches.
@@ -106,10 +84,15 @@ findEquivCells1(const LibertyLibrary *library)
 	while (match_iter.hasNext()) {
 	  LibertyCell *match = match_iter.next();
 	  if (equivCells(match, cell)) {
-	    LibertyCellSeq *equivs = cell_equivs->findKey(match);
+	    LibertyCellSeq *equivs = match->equivCellsRaw();
+	    if (equivs == nullptr) {
+	      equivs = new LibertyCellSeq;
+	      equivs->push_back(match);
+	      match->setEquivCells(equivs);
+	      cell_equivs.insert(match);
+	    }
 	    equivs->push_back(cell);
-	    (*cell_equivs)[cell] = equivs;
-	    found_equiv = true;
+	    cell->setEquivCells(equivs);
 	    break;
 	  }
 	}
@@ -119,16 +102,9 @@ findEquivCells1(const LibertyLibrary *library)
 	cell_hash[hash] = matches;
       }
       matches->push_back(cell);
-      if (!found_equiv) {
-	LibertyCellSeq *equivs = new LibertyCellSeq;
-	equivs->push_back(cell);
-	(*cell_equivs)[cell] = equivs;
-      }
     }
   }
-
   cell_hash.deleteContents();
-  return cell_equivs;
 }
 
 struct CellDriveResistanceLess
@@ -141,11 +117,10 @@ struct CellDriveResistanceLess
 };
 
 static void
-sortCellEquivs(LibertyCellEquivMap *cell_equivs)
+sortCellEquivs(LibertyCellSet &cell_equivs)
 {
-  LibertyCellEquivMap::Iterator equivs_iter(cell_equivs);
-  while (equivs_iter.hasNext()) {
-    LibertyCellSeq *equivs = equivs_iter.next();
+  for (auto equiv : cell_equivs) {
+    LibertyCellSeq *equivs = equiv->equivCells();
     sort(equivs, CellDriveResistanceLess());
     LibertyCell *lower = nullptr;
     LibertyCellSeq::Iterator cell_iter(equivs);

liberty/EquivCells.hh

@@ -23,12 +23,9 @@
 namespace sta {
 
 // Find equivalent cells, sort by drive strength and
-// and set cell->higherDrive/lowerDrive.
-LibertyCellEquivMap *
-findEquivCells(const LibertyLibrary *library);
-// Delete findEquivCells return value.
+// and set cell->equivCells/higherDrive/lowerDrive.
 void
-deleteEquivCellMap(LibertyCellEquivMap *equiv_map);
+findEquivCells(const LibertyLibrary *library);
 
 // Predicate that is true when the ports, functions, sequentials and
 // timing arcs match.

liberty/Liberty.cc

@@ -84,7 +84,7 @@ LibertyLibrary::LibertyLibrary(const char *name,
   default_operating_conditions_(nullptr),
   ocv_arc_depth_(0.0),
   default_ocv_derate_(nullptr),
-  equiv_cell_map_(nullptr),
+  found_equiv_cells_(false),
   buffers_(nullptr)
 {
   // Scalar templates are builtin.
@@ -132,7 +132,6 @@ LibertyLibrary::~LibertyLibrary()
     const char *supply_name = name_volt.first;
     stringDelete(supply_name);
   }
-  deleteEquivCellMap(equiv_cell_map_);
   delete buffers_;
 }
 
@@ -154,6 +153,15 @@ LibertyLibrary::findLibertyCellsMatching(PatternMatch *pattern,
   }
 }
 
+void
+LibertyLibrary::ensureEquivCells()
+{
+  if (!found_equiv_cells_) {
+    findEquivCells(this);
+    found_equiv_cells_ = true;
+  }
+}
+
 LibertyCellSeq *
 LibertyLibrary::buffers()
 {
@@ -757,20 +765,6 @@ LibertyLibrary::makeCornerMap(LibertyCell *cell1,
   }
 }
 
-void
-LibertyLibrary::ensureEquivCells()
-{
-  if (equiv_cell_map_ == nullptr)
-    equiv_cell_map_ = sta::findEquivCells(this);
-}
-
-LibertyCellSeq *
-LibertyLibrary::findEquivCells(LibertyCell *cell)
-{
-  ensureEquivCells();
-  return equiv_cell_map_->findKey(cell);
-}
-
 ////////////////////////////////////////////////////////////////
 
 float
@@ -873,6 +867,7 @@ LibertyCell::LibertyCell(LibertyLibrary *library,
   is_disabled_constraint_(false),
   leakage_power_(0.0),
   leakage_power_exists_(false),
+  equiv_cells_(nullptr),
   higher_drive_(nullptr),
   lower_drive_(nullptr)
 {
@@ -889,6 +884,14 @@ LibertyCell::~LibertyCell()
   timing_arc_set_from_map_.deleteContents();
   timing_arc_set_to_map_.deleteContents();
 
+  if (equiv_cells_) {
+    // equiv_cells_ is shared by all of the equivalent cells, so
+    // delete it once for all of them and null them.
+    for (auto equiv : *equiv_cells_)
+      equiv->setEquivCells(nullptr);
+    delete equiv_cells_;
+  }
+
   deleteInternalPowerAttrs();
   internal_powers_.deleteContents();
   leakage_powers_.deleteContents();
@@ -1457,6 +1460,20 @@ LibertyCell::setCornerCell(LibertyCell *corner_cell,
 
 ////////////////////////////////////////////////////////////////
 
+LibertyCellSeq *
+LibertyCell::equivCells()
+{
+  if (equiv_cells_ == nullptr)
+    liberty_library_->ensureEquivCells();
+  return equiv_cells_;
+}
+
+void
+LibertyCell::setEquivCells(LibertyCellSeq *equiv_cells)
+{
+  equiv_cells_ = equiv_cells;
+}
+
 LibertyCell *
 LibertyCell::higherDrive() const
 {

liberty/Liberty.hh

@@ -118,7 +118,6 @@ public:
   LibertyCell *findLibertyCell(const char *name) const;
   void findLibertyCellsMatching(PatternMatch *pattern,
 				LibertyCellSeq *cells);
-  LibertyCellSeq *findEquivCells(LibertyCell *cell);
   // Liberty cells that are buffers.
   LibertyCellSeq *buffers();
 
@@ -331,7 +330,7 @@ protected:
   OcvDerate *default_ocv_derate_;
   OcvDerateMap ocv_derate_map_;
   SupplyVoltageMap supply_voltage_map_;
-  LibertyCellEquivMap *equiv_cell_map_;
+  bool found_equiv_cells_;
   LibertyCellSeq *buffers_;
 
   // Set if any library has rise/fall capacitances.
@@ -493,6 +492,10 @@ public:
   virtual void finish(bool infer_latches,
 		      Report *report,
 		      Debug *debug);
+  LibertyCellSeq *equivCells();
+  // Internal.
+  LibertyCellSeq *equivCellsRaw() { return equiv_cells_; }
+  void setEquivCells(LibertyCellSeq *equiv_cells);
   void setHigherDrive(LibertyCell *cell);
   void setLowerDrive(LibertyCell *cell);
   bool isBuffer() const;
@@ -565,6 +568,7 @@ protected:
   float leakage_power_;
   bool leakage_power_exists_;
   LibertyPgPortMap pg_port_map_;
+  LibertyCellSeq *equiv_cells_;
   // Next higher/lower drive equivalent cells.
   LibertyCell *higher_drive_;
   LibertyCell *lower_drive_;

tcl/StaTcl.i

@@ -2282,8 +2282,7 @@ find_library_buffers(LibertyLibrary *library)
 LibertyCellSeq *
 equiv_cells(LibertyCell *cell)
 {
-  LibertyLibrary *library = cell->libertyLibrary();
-  return library->findEquivCells(cell);
+  return cell->equivCells();
 }
 
 bool