[turbofan] Memory improvements for escape analysis

src/compiler/escape-analysis.h

 // Copyright 2015 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_ESCAPE_ANALYSIS_H_
 #define V8_COMPILER_ESCAPE_ANALYSIS_H_
 
 #include "src/base/flags.h"
 #include "src/compiler/graph.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // Forward declarations.
 class CommonOperatorBuilder;
 class EscapeAnalysis;
 class VirtualState;
 class VirtualObject;
 
 
 // EscapeStatusAnalysis determines for each allocation whether it escapes.
 class EscapeStatusAnalysis {
  public:
+  typedef NodeId Alias;
   ~EscapeStatusAnalysis();
 
-  enum EscapeStatusFlag {
+  enum Status {
     kUnknown = 0u,
     kTracked = 1u << 0,
     kEscaped = 1u << 1,
     kOnStack = 1u << 2,
     kVisited = 1u << 3,
+    kDanglingComputed = 1u << 4,

[Jarin, 2016/01/22 13:36:11]

Could we have some comments that gives some explanation for the new states? (The
old states are obvious.)

[sigurds, 2016/01/25 10:34:56]

Done.

+    kDangling = 1u << 5,
+    kBranchPointComputed = 1u << 6,
+    kBranchPoint = 1u << 7,
   };
-  typedef base::Flags<EscapeStatusFlag, unsigned char> EscapeStatusFlags;
+  typedef base::Flags<Status, unsigned char> StatusFlags;
 
-  void Run();
+  void RunStatusAnalysis();
 
   bool IsVirtual(Node* node);
   bool IsEscaped(Node* node);
   bool IsAllocation(Node* node);
-
   void DebugPrint();
 
-  friend class EscapeAnalysis;
+ protected:
+  EscapeStatusAnalysis(EscapeAnalysis* object_analysis, Graph* graph,
+                       Zone* zone);
+  void EnqueueForStatusAnalysis(Node* node);
+  bool SetEscaped(Node* node);
+  bool IsEffectBranchPoint(Node* node);
+  bool IsDanglingEffectNode(Node* node);
+  void ResizeStatusVector();
+  size_t GetStatusVectorSize();
+  bool IsVirtual(NodeId id);
+
+  Graph* graph() const { return graph_; }
+  Zone* zone() const { return zone_; }
+  void AssignAliases();
+  Alias GetAlias(NodeId id) const { return aliases_[id]; }
+  const ZoneVector<Alias>& GetAliasMap() const { return aliases_; }
+  Alias AliasCount() const { return next_free_alias_; }
+  static const Alias kNotReachable;
+  static const Alias kUntrackable;
+
+  bool IsNotReachable(Node* node);
+
+  ZoneVector<Node*> stack_;
 
  private:
-  EscapeStatusAnalysis(EscapeAnalysis* object_analysis, Graph* graph,
-                       Zone* zone);
   void Process(Node* node);
   void ProcessAllocate(Node* node);
   void ProcessFinishRegion(Node* node);
   void ProcessStoreField(Node* node);
   void ProcessStoreElement(Node* node);
   bool CheckUsesForEscape(Node* node, bool phi_escaping = false) {
     return CheckUsesForEscape(node, node, phi_escaping);
   }
   bool CheckUsesForEscape(Node* node, Node* rep, bool phi_escaping = false);
   void RevisitUses(Node* node);
   void RevisitInputs(Node* node);
-  bool SetEscaped(Node* node);
-  bool IsVirtual(NodeId id);
+
+  Alias NextAlias() { return next_free_alias_++; }
+
   bool HasEntry(Node* node);
-  void Resize();
-  size_t size();
+
   bool IsAllocationPhi(Node* node);
 
-  Graph* graph() const { return graph_; }
-  Zone* zone() const { return zone_; }
-
   EscapeAnalysis* object_analysis_;
   Graph* const graph_;
   Zone* const zone_;
-  ZoneVector<EscapeStatusFlags> status_;
-  ZoneDeque<Node*> queue_;
+  ZoneVector<StatusFlags> status_;
+  Alias next_free_alias_;
+  ZoneVector<Node*> status_stack_;
+  ZoneVector<Alias> aliases_;
 
   DISALLOW_COPY_AND_ASSIGN(EscapeStatusAnalysis);
 };
 
 
-DEFINE_OPERATORS_FOR_FLAGS(EscapeStatusAnalysis::EscapeStatusFlags)
+DEFINE_OPERATORS_FOR_FLAGS(EscapeStatusAnalysis::StatusFlags)
 
 
 // Forward Declaration.
 class MergeCache;
 
 
 // EscapeObjectAnalysis simulates stores to determine values of loads if
 // an object is virtual and eliminated.
-class EscapeAnalysis {
+class EscapeAnalysis : private EscapeStatusAnalysis {

[Jarin, 2016/01/22 13:36:11]

Is there a good reason to inherit? Is it just to save you from writing the
accessors in this class? If yes, that I would prefer to keep the classes
separate.

[sigurds, 2016/01/25 10:34:56]

Done.

  public:
-  typedef NodeId Alias;
-
   EscapeAnalysis(Graph* graph, CommonOperatorBuilder* common, Zone* zone);
   ~EscapeAnalysis();
 
   void Run();
 
   Node* GetReplacement(Node* node);
   bool IsVirtual(Node* node);
   bool IsEscaped(Node* node);
   bool CompareVirtualObjects(Node* left, Node* right);
   Node* GetOrCreateObjectState(Node* effect, Node* node);
   bool ExistsVirtualAllocate();
 
  private:
   void RunObjectAnalysis();
-  void AssignAliases();
   bool Process(Node* node);
   void ProcessLoadField(Node* node);
   void ProcessStoreField(Node* node);
   void ProcessLoadElement(Node* node);
   void ProcessStoreElement(Node* node);
   void ProcessAllocationUsers(Node* node);
   void ProcessAllocation(Node* node);
   void ProcessFinishRegion(Node* node);
   void ProcessCall(Node* node);
   void ProcessStart(Node* node);
   bool ProcessEffectPhi(Node* node);
   void ProcessLoadFromPhi(int offset, Node* from, Node* node,
                           VirtualState* states);
 
   void ForwardVirtualState(Node* node);
-  bool IsEffectBranchPoint(Node* node);
-  bool IsDanglingEffectNode(Node* node);
   int OffsetFromAccess(Node* node);
-
+  VirtualState* CopyForModificationAt(VirtualState* state, Node* node);
+  VirtualObject* CopyForModificationAt(VirtualObject* obj, VirtualState* state,
+                                       Node* node);
   VirtualObject* GetVirtualObject(Node* at, NodeId id);
   VirtualObject* ResolveVirtualObject(VirtualState* state, Node* node);
   Node* GetReplacementIfSame(ZoneVector<VirtualObject*>& objs);
 
   bool SetEscaped(Node* node);
   Node* replacement(NodeId id);
   Node* replacement(Node* node);
   Node* ResolveReplacement(Node* node);
   Node* GetReplacement(NodeId id);
   bool SetReplacement(Node* node, Node* rep);
   bool UpdateReplacement(VirtualState* state, Node* node, Node* rep);
 
   VirtualObject* GetVirtualObject(VirtualState* state, Node* node);
 
   void DebugPrint();
   void DebugPrintState(VirtualState* state);
   void DebugPrintObject(VirtualObject* state, Alias id);
 
-  Alias NextAlias() { return next_free_alias_++; }
-  Alias AliasCount() const { return next_free_alias_; }
+  CommonOperatorBuilder* common() const { return common_; }
 
-  Graph* graph() const { return graph_; }
-  CommonOperatorBuilder* common() const { return common_; }
-  Zone* zone() const { return zone_; }
-
-  static const Alias kNotReachable;
-  static const Alias kUntrackable;
-  Graph* const graph_;
   CommonOperatorBuilder* const common_;
-  Zone* const zone_;
   ZoneVector<VirtualState*> virtual_states_;
   ZoneVector<Node*> replacements_;
-  EscapeStatusAnalysis escape_status_;
   MergeCache* cache_;
-  ZoneVector<Alias> aliases_;
-  Alias next_free_alias_;
 
   DISALLOW_COPY_AND_ASSIGN(EscapeAnalysis);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_ESCAPE_ANALYSIS_H_