Get rid of ZoneScope completely.

src/zone.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 21 matching lines @@
 #include "checks.h"
 #include "hashmap.h"
 #include "globals.h"
 #include "list.h"
 #include "splay-tree.h"
 
 namespace v8 {
 namespace internal {
 
 
-// Zone scopes are in one of two modes.  Either they delete the zone
-// on exit or they do not.
-enum ZoneScopeMode {
-  DELETE_ON_EXIT,
-  DONT_DELETE_ON_EXIT
-};
-
 class Segment;
 class Isolate;
 
 // The Zone supports very fast allocation of small chunks of
 // memory. The chunks cannot be deallocated individually, but instead
 // the Zone supports deallocating all chunks in one fast
 // operation. The Zone is used to hold temporary data structures like
 // the abstract syntax tree, which is deallocated after compilation.
 
 // Note: There is no need to initialize the Zone; the first time an
 // allocation is attempted, a segment of memory will be requested
 // through a call to malloc().
 
 // Note: The implementation is inherently not thread safe. Do not use
 // from multi-threaded code.
 
 class Zone {
  public:
   explicit Zone(Isolate* isolate);
-  ~Zone() { DeleteKeptSegment(); }
+  ~Zone();
   // Allocate 'size' bytes of memory in the Zone; expands the Zone by
   // allocating new segments of memory on demand using malloc().
   inline void* New(int size);
 
   template <typename T>
   inline T* NewArray(int length);
 
-  // Deletes all objects and free all memory allocated in the Zone. Keeps one
-  // small (size <= kMaximumKeptSegmentSize) segment around if it finds one.
-  void DeleteAll();
-
-  // Deletes the last small segment kept around by DeleteAll().
-  void DeleteKeptSegment();
-
   // Returns true if more memory has been allocated in zones than
   // the limit allows.
   inline bool excess_allocation();
 
   inline void adjust_segment_bytes_allocated(int delta);
 
   inline unsigned allocation_size() { return allocation_size_; }
 
   inline Isolate* isolate() { return isolate_; }
 
  private:
   friend class Isolate;
-  friend class ZoneScope;
 
   // All pointers returned from New() have this alignment.  In addition, if the
   // object being allocated has a size that is divisible by 8 then its alignment
   // will be 8.
   static const int kAlignment = kPointerSize;
 
   // Never allocate segments smaller than this size in bytes.
   static const int kMinimumSegmentSize = 8 * KB;
 
   // Never allocate segments larger than this size in bytes.
   static const int kMaximumSegmentSize = 1 * MB;
 
-  // Never keep segments larger than this size in bytes around.
-  static const int kMaximumKeptSegmentSize = 64 * KB;
-
   // Report zone excess when allocation exceeds this limit.
   int zone_excess_limit_;
 
   // The number of bytes allocated in this zone so far.
   unsigned allocation_size_;
 
   // The number of bytes allocated in segments.  Note that this number
   // includes memory allocated from the OS but not yet allocated from
   // the zone.
   int segment_bytes_allocated_;
@@ skipping 10 matching lines @@
 
   // Deletes the given segment. Does not touch the segment chain.
   void DeleteSegment(Segment* segment, int size);
 
   // The free region in the current (front) segment is represented as
   // the half-open interval [position, limit). The 'position' variable
   // is guaranteed to be aligned as dictated by kAlignment.
   Address position_;
   Address limit_;
 
-  int scope_nesting_;
-
   Segment* segment_head_;
   Isolate* isolate_;
 };
 
 
 // ZoneObject is an abstraction that helps define classes of objects
 // allocated in the Zone. Use it as a base class; see ast.h.
 class ZoneObject {
  public:
   // Allocate a new ZoneObject of 'size' bytes in the Zone.
@@ skipping 72 matching lines @@
   INLINE(void Initialize(int capacity, Zone* zone)) {
     List<T, ZoneAllocationPolicy>::Initialize(capacity,
                                               ZoneAllocationPolicy(zone));
   }
 
   void operator delete(void* pointer) { UNREACHABLE(); }
   void operator delete(void* pointer, Zone* zone) { UNREACHABLE(); }
 };
 
 
-// ZoneScopes keep track of the current parsing and compilation
-// nesting and cleans up generated ASTs in the Zone when exiting the
-// outer-most scope.
-class ZoneScope BASE_EMBEDDED {
- public:
-  INLINE(ZoneScope(Zone* zone, ZoneScopeMode mode));
-
-  virtual ~ZoneScope();
-
-  Zone* zone() const { return zone_; }
-
-  inline bool ShouldDeleteOnExit();
-
-  // For ZoneScopes that do not delete on exit by default, call this
-  // method to request deletion on exit.
-  void DeleteOnExit() {
-    mode_ = DELETE_ON_EXIT;
-  }
-
-  inline static int nesting();
-
- private:
-  Zone* zone_;
-  ZoneScopeMode mode_;
-};
-
-
 // A zone splay tree.  The config type parameter encapsulates the
 // different configurations of a concrete splay tree (see splay-tree.h).
 // The tree itself and all its elements are allocated in the Zone.
 template <typename Config>
 class ZoneSplayTree: public SplayTree<Config, ZoneAllocationPolicy> {
  public:
   explicit ZoneSplayTree(Zone* zone)
       : SplayTree<Config, ZoneAllocationPolicy>(ZoneAllocationPolicy(zone)) {}
   ~ZoneSplayTree();
 };
 
 
 typedef TemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap;
 
 } }  // namespace v8::internal
 
 #endif  // V8_ZONE_H_