Fix memory leaks in ~Zone and ~Isolate

src/zone.cc

 // Copyright 2011 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 16 matching lines @@
 
 #include "v8.h"
 
 #include "zone-inl.h"
 #include "splay-tree-inl.h"
 
 namespace v8 {
 namespace internal {
 
 
-Zone::Zone()
-    : zone_excess_limit_(256 * MB),
-      segment_bytes_allocated_(0),
-      position_(0),
-      limit_(0),
-      scope_nesting_(0),
-      segment_head_(NULL) {
-}
-unsigned Zone::allocation_size_ = 0;
-
-
-ZoneScope::~ZoneScope() {
-  ASSERT_EQ(Isolate::Current(), isolate_);
-  if (ShouldDeleteOnExit()) isolate_->zone()->DeleteAll();
-  isolate_->zone()->scope_nesting_--;
-}
-
-
 // Segments represent chunks of memory: They have starting address
 // (encoded in the this pointer) and a size in bytes. Segments are
 // chained together forming a LIFO structure with the newest segment
 // available as segment_head_. Segments are allocated using malloc()
 // and de-allocated using free().
 
 class Segment {
  public:
+  void Initialize(Segment* next, int size) {
+    next_ = next;
+    size_ = size;
+  }
+
   Segment* next() const { return next_; }
   void clear_next() { next_ = NULL; }
 
   int size() const { return size_; }
   int capacity() const { return size_ - sizeof(Segment); }
 
   Address start() const { return address(sizeof(Segment)); }
   Address end() const { return address(size_); }
 
  private:
   // Computes the address of the nth byte in this segment.
   Address address(int n) const {
     return Address(this) + n;
   }
 
   Segment* next_;
   int size_;
+};
 
-  friend class Zone;
-};
+
+Zone::Zone()
+    : zone_excess_limit_(256 * MB),
+      segment_bytes_allocated_(0),
+      position_(0),
+      limit_(0),
+      scope_nesting_(0),
+      segment_head_(NULL) {
+}
+unsigned Zone::allocation_size_ = 0;
+
+ZoneScope::~ZoneScope() {
+  ASSERT_EQ(Isolate::Current(), isolate_);
+  if (ShouldDeleteOnExit()) isolate_->zone()->DeleteAll();
+  isolate_->zone()->scope_nesting_--;
+}
 
 
 // Creates a new segment, sets it size, and pushes it to the front
 // of the segment chain. Returns the new segment.
 Segment* Zone::NewSegment(int size) {
   Segment* result = reinterpret_cast<Segment*>(Malloced::New(size));
   adjust_segment_bytes_allocated(size);
   if (result != NULL) {
-    result->next_ = segment_head_;
-    result->size_ = size;
+    result->Initialize(segment_head_, size);
     segment_head_ = result;
   }
   return result;
 }
 
 
 // Deletes the given segment. Does not touch the segment chain.
 void Zone::DeleteSegment(Segment* segment, int size) {
   adjust_segment_bytes_allocated(-size);
   Malloced::Delete(segment);
@@ skipping 45 matching lines @@
 #endif
   } else {
     position_ = limit_ = 0;
   }
 
   // Update the head segment to be the kept segment (if any).
   segment_head_ = keep;
 }
 
 
+void Zone::DeleteKeptSegment() {
+  if (segment_head_ != NULL) {
+    DeleteSegment(segment_head_, segment_head_->size());
+    segment_head_ = NULL;
+  }
+}
+
+
 Address Zone::NewExpand(int size) {
   // Make sure the requested size is already properly aligned and that
   // there isn't enough room in the Zone to satisfy the request.
   ASSERT(size == RoundDown(size, kAlignment));
   ASSERT(position_ + size > limit_);
 
   // Compute the new segment size. We use a 'high water mark'
   // strategy, where we increase the segment size every time we expand
   // except that we employ a maximum segment size when we delete. This
   // is to avoid excessive malloc() and free() overhead.
@@ skipping 19 matching lines @@
   // Recompute 'top' and 'limit' based on the new segment.
   Address result = RoundUp(segment->start(), kAlignment);
   position_ = result + size;
   limit_ = segment->end();
   ASSERT(position_ <= limit_);
   return result;
 }
 
 
 } }  // namespace v8::internal