Fix memory leaks in ~Zone and ~Isolate

src/zone.cc

Index: src/zone.cc
diff --git a/src/zone.cc b/src/zone.cc
index 42ce8c5cb7c2d72392c3f80cbbc92f42ac418cf4..7574778f539acb9db63f73e79218a9fa0a3cd9ee 100644
--- a/src/zone.cc
+++ b/src/zone.cc
@@ -34,24 +34,6 @@ 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
@@ -60,6 +42,11 @@ ZoneScope::~ZoneScope() {
 
 class Segment {
  public:
+  void Initialize(Segment* next, int size) {
+    next_ = next;
+    size_ = size;
+  }
+
   Segment* next() const { return next_; }
   void clear_next() { next_ = NULL; }
 
@@ -77,19 +64,33 @@ class Segment {
 
   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;
@@ -155,6 +156,14 @@ void Zone::DeleteAll() {
 }
 
 
+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.