Make special RPO computation iterative during scheduling.

src/compiler/scheduler.h

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_SCHEDULER_H_
 #define V8_COMPILER_SCHEDULER_H_
 
 #include "src/v8.h"
 
 #include "src/compiler/opcodes.h"
 #include "src/compiler/schedule.h"
 #include "src/compiler/zone-pool.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
+class SpecialRPONumberer;
+
 // Computes a schedule from a graph, placing nodes into basic blocks and
 // ordering the basic blocks in the special RPO order.
 class Scheduler {
  public:
   // The complete scheduling algorithm. Creates a new schedule and places all
   // nodes from the graph into it.
   static Schedule* ComputeSchedule(ZonePool* zone_pool, Graph* graph);
 
   // Compute the RPO of blocks in an existing schedule.
   static BasicBlockVector* ComputeSpecialRPO(ZonePool* zone_pool,
@@ skipping 24 matching lines @@
                                  // coupled to another node, or not yet known.
   };
 
   Zone* zone_;
   Graph* graph_;
   Schedule* schedule_;
   NodeVectorVector scheduled_nodes_;     // Per-block list of nodes in reverse.
   NodeVector schedule_root_nodes_;       // Fixed root nodes seed the worklist.
   ZoneQueue<Node*> schedule_queue_;      // Worklist of schedulable nodes.
   ZoneVector<SchedulerData> node_data_;  // Per-node data for all nodes.
+  SpecialRPONumberer* special_rpo_;      // Special RPO numbering of blocks.
 
   Scheduler(Zone* zone, Graph* graph, Schedule* schedule);
 
   inline SchedulerData DefaultSchedulerData();
   inline SchedulerData* GetData(Node* node);
 
   Placement GetPlacement(Node* node);
   void UpdatePlacement(Node* node, Placement placement);
 
   inline bool IsCoupledControlEdge(Node* node, int index);
   void IncrementUnscheduledUseCount(Node* node, int index, Node* from);
   void DecrementUnscheduledUseCount(Node* node, int index, Node* from);
 
-  inline int GetRPONumber(BasicBlock* block);
   BasicBlock* GetCommonDominator(BasicBlock* b1, BasicBlock* b2);
 
   // Phase 1: Build control-flow graph.
   friend class CFGBuilder;
   void BuildCFG();
 
   // Phase 2: Compute special RPO and dominator tree.
   friend class SpecialRPONumberer;
   void ComputeSpecialRPONumbering();
   void GenerateImmediateDominatorTree();
 
   // Phase 3: Prepare use counts for nodes.
   friend class PrepareUsesVisitor;
   void PrepareUses();
 
   // Phase 4: Schedule nodes early.
   friend class ScheduleEarlyNodeVisitor;
   void ScheduleEarly();
 
   // Phase 5: Schedule nodes late.
   friend class ScheduleLateNodeVisitor;
   void ScheduleLate();
 
+  // Phase 6: Seal the final schedule.
+  void SealFinalSchedule();
+
   void FuseFloatingControl(BasicBlock* block, Node* node);
   void MovePlannedNodes(BasicBlock* from, BasicBlock* to);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SCHEDULER_H_