One Zone per CompilationInfo.

src/zone.cc

Index: src/zone.cc
diff --git a/src/zone.cc b/src/zone.cc
index d5d05ab95f21bb1f003e1a0334593df0de0dfcdd..7cfc7207d3e4738a376583abb627fd0fd173e8ec 100644
--- a/src/zone.cc
+++ b/src/zone.cc
@@ -67,20 +67,20 @@ class Segment {
 };
 
 
-Zone::Zone()
+Zone::Zone(Isolate* isolate)
     : zone_excess_limit_(256 * MB),
       segment_bytes_allocated_(0),
       position_(0),
       limit_(0),
       scope_nesting_(0),
-      segment_head_(NULL) {
+      segment_head_(NULL),
+      isolate_(isolate) {
 }
 unsigned Zone::allocation_size_ = 0;
 
 ZoneScope::~ZoneScope() {
-  ASSERT_EQ(Isolate::Current(), isolate_);
-  if (ShouldDeleteOnExit()) isolate_->zone()->DeleteAll();
-  isolate_->zone()->scope_nesting_--;
+  if (ShouldDeleteOnExit()) zone_->Destroy();
+  zone_->scope_nesting_--;
 }
 
 
@@ -104,11 +104,38 @@ void Zone::DeleteSegment(Segment* segment, int size) {
 }
 
 
+void Zone::Destroy() {
+  if (isolate_->runtime_zone() == this)

[danno, 2012/06/14 14:22:19]

Yikes! Please move the DeleteAll(DELETE_ALL_BLOCKS) into ~Zone(), and call
DeleteAll(DELETE_ALL_BUT_LAST_BLOCK) where it used to be called.

[sanjoy, 2012/06/15 09:24:31]

Moved deletion to the destructor.

+    DeleteAllButOne();
+  else
+    DeleteAll();
+}
+
+
 void Zone::DeleteAll() {
 #ifdef DEBUG
   // Constant byte value used for zapping dead memory in debug mode.
   static const unsigned char kZapDeadByte = 0xcd;
 #endif
+  Segment* current = segment_head_;
+  while (current != NULL) {
+    Segment* next = current->next();
+    int size = current->size();
+#ifdef DEBUG
+    // Zap the entire current segment (including the header).
+    memset(current, kZapDeadByte, size);
+#endif
+    DeleteSegment(current, size);
+    current = next;
+  }
+}
+
+
+void Zone::DeleteAllButOne() {

[danno, 2012/06/14 14:22:19]

Just add a enum flag to DeleteAll that handles the last block specially.

[sanjoy, 2012/06/15 09:24:31]

Moved deletion to the destructor.

+#ifdef DEBUG
+  // Constant byte value used for zapping dead memory in debug mode.
+  static const unsigned char kZapDeadByte = 0xcd;
+#endif
 
   // Find a segment with a suitable size to keep around.
   Segment* keep = segment_head_;