Chain ScopeInfos together

src/objects.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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 #include <memory>
 
@@ skipping 4373 matching lines @@
   // must be an internalized string.
   int FunctionContextSlotIndex(String* name);
 
   // Lookup support for serialized scope info.  Returns the receiver context
   // slot index if scope has a "this" binding, and the binding is
   // context-allocated.  Otherwise returns a value < 0.
   int ReceiverContextSlotIndex();
 
   FunctionKind function_kind();
 
-  static Handle<ScopeInfo> Create(Isolate* isolate, Zone* zone, Scope* scope);
-  static Handle<ScopeInfo> CreateForWithScope(Isolate* isolate);
+  // Returns true if this ScopeInfo is linked to a outer ScopeInfo.
+  bool HasOuterScopeInfo();
+
+  // Return the outer ScopeInfo if present.
+  ScopeInfo* OuterScopeInfo();
+
+#ifdef DEBUG
+  bool Equals(ScopeInfo* other) const;
+#endif
+
+  static Handle<ScopeInfo> Create(Isolate* isolate, Zone* zone, Scope* scope,
+                                  MaybeHandle<ScopeInfo> outer_scope);
+  static Handle<ScopeInfo> CreateForWithScope(
+      Isolate* isolate, MaybeHandle<ScopeInfo> outer_scope);
   static Handle<ScopeInfo> CreateGlobalThisBinding(Isolate* isolate);
 
   // Serializes empty scope info.
   static ScopeInfo* Empty(Isolate* isolate);
 
 #ifdef DEBUG
   void Print();
 #endif
 
   // The layout of the static part of a ScopeInfo is as follows. Each entry is
@@ skipping 50 matching lines @@
   //    context local, so in total this part occupies ContextLocalCount()
   //    slots in the array.
   // 6. ReceiverEntry:
   //    If the scope binds a "this" value, one slot is reserved to hold the
   //    context or stack slot index for the variable.
   // 7. FunctionNameEntry:
   //    If the scope belongs to a named function expression this part contains
   //    information about the function variable. It always occupies two array
   //    slots:  a. The name of the function variable.
   //            b. The context or stack slot index for the variable.
-  // 8. ModuleInfoEntry, ModuleVariableCount, and ModuleVariableEntries:
+  // 8. OuterScopeInfoEntryIndex:
+  //    The outer scope's ScopeInfo or the hole if there's none.
+  // 9. ModuleInfoEntry, ModuleVariableCount, and ModuleVariableEntries:
   //    For a module scope, this part contains the ModuleInfo, the number of
   //    MODULE-allocated variables, and the metadata of those variables.  For
   //    non-module scopes it is empty.
   int ParameterEntriesIndex();
   int StackLocalFirstSlotIndex();
   int StackLocalEntriesIndex();
   int ContextLocalNameEntriesIndex();
   int ContextLocalInfoEntriesIndex();
   int ReceiverEntryIndex();
   int FunctionNameEntryIndex();
+  int OuterScopeInfoEntryIndex();
   int ModuleInfoEntryIndex();
   int ModuleVariableCountIndex();
   int ModuleVariableEntriesIndex();
 
   int Lookup(Handle<String> name, int start, int end, VariableMode* mode,
              VariableLocation* location, InitializationFlag* init_flag,
              MaybeAssignedFlag* maybe_assigned_flag);
 
   // Used for the function name variable for named function expressions, and for
   // the receiver.
@@ skipping 14 matching lines @@
       : public BitField<bool, ReceiverVariableField::kNext, 1> {};
   class FunctionVariableField
       : public BitField<VariableAllocationInfo, HasNewTargetField::kNext, 2> {};
   class AsmModuleField
       : public BitField<bool, FunctionVariableField::kNext, 1> {};
   class AsmFunctionField : public BitField<bool, AsmModuleField::kNext, 1> {};
   class HasSimpleParametersField
       : public BitField<bool, AsmFunctionField::kNext, 1> {};
   class FunctionKindField
       : public BitField<FunctionKind, HasSimpleParametersField::kNext, 9> {};
+  class HasOuterScopeInfoField
+      : public BitField<bool, FunctionKindField::kNext, 1> {};
 
   // Properties of variables.
   class VariableModeField : public BitField<VariableMode, 0, 3> {};
   class InitFlagField : public BitField<InitializationFlag, 3, 1> {};
   class MaybeAssignedFlagField : public BitField<MaybeAssignedFlag, 4, 1> {};
 
   friend class ScopeIterator;
 };
 
 // ModuleInfo is to ModuleDescriptor what ScopeInfo is to Scope.
 class ModuleInfo : public FixedArray {
  public:
   DECLARE_CAST(ModuleInfo)
   static Handle<ModuleInfo> New(Isolate* isolate, ModuleDescriptor* descr);
   inline FixedArray* special_exports() const;
   inline FixedArray* regular_exports() const;
 
+#ifdef DEBUG
+  inline bool Equals(ModuleInfo* other) const;
+#endif
+
  private:
   friend class Factory;
   enum { kSpecialExportsIndex, kRegularExportsIndex, kLength };
 };
 
 // The cache for maps used by normalized (dictionary mode) objects.
 // Such maps do not have property descriptors, so a typical program
 // needs very limited number of distinct normalized maps.
 class NormalizedMapCache: public FixedArray {
  public:
@@ skipping 6666 matching lines @@
     }
     return value;
   }
 };
 
 
 }  // NOLINT, false-positive due to second-order macros.
 }  // NOLINT, false-positive due to second-order macros.
 
 #endif  // V8_OBJECTS_H_