[Compiler] Enable use of seperate zones for parsing and compiling.

src/zone/zone.cc

 // Copyright 2012 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.
 
 #include "src/zone/zone.h"
 
 #include <cstring>
 
 #include "src/utils.h"
 #include "src/v8.h"
@@ skipping 31 matching lines @@
 
 }  // namespace
 
 Zone::Zone(AccountingAllocator* allocator, const char* name)
     : allocation_size_(0),
       segment_bytes_allocated_(0),
       position_(0),
       limit_(0),
       allocator_(allocator),
       segment_head_(nullptr),
-      name_(name) {
+      name_(name),
+      sealed_(false) {
   allocator_->ZoneCreation(this);
 }
 
 Zone::~Zone() {
   allocator_->ZoneDestruction(this);
 
   DeleteAll();
 
   DCHECK(segment_bytes_allocated_ == 0);
 }
 
 void* Zone::New(size_t size) {
+  CHECK(!sealed_);
+
   // Round up the requested size to fit the alignment.
   size = RoundUp(size, kAlignment);
 
   // If the allocation size is divisible by 8 then we return an 8-byte aligned
   // address.
   if (kPointerSize == 4 && kAlignment == 4) {
     position_ += ((~size) & 4) & (reinterpret_cast<intptr_t>(position_) & 4);
   } else {
     DCHECK(kAlignment >= kPointerSize);
   }
@@ skipping 105 matching lines @@
   // size bytes + header and alignment padding)
   DCHECK(reinterpret_cast<uintptr_t>(position_) >=
          reinterpret_cast<uintptr_t>(result));
   limit_ = segment->end();
   DCHECK(position_ <= limit_);
   return result;
 }
 
 }  // namespace internal
 }  // namespace v8