[heap] Fix address space leak in Unmapper

src/heap/spaces.h

 // Copyright 2011 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.
 
 #ifndef V8_HEAP_SPACES_H_
 #define V8_HEAP_SPACES_H_
 
 #include <list>
 #include <memory>
 #include <unordered_set>
@@ skipping 1079 matching lines @@
   STATIC_ASSERT(Page::kPageSize % kRegionSize == 0);
 
   Address starts_[kSize];
 };
 
 
 // ----------------------------------------------------------------------------
 // A space acquires chunks of memory from the operating system. The memory
 // allocator allocates and deallocates pages for the paged heap spaces and large
 // pages for large object space.
-class MemoryAllocator {
+class V8_EXPORT_PRIVATE MemoryAllocator {
  public:
   // Unmapper takes care of concurrently unmapping and uncommitting memory
   // chunks.
   class Unmapper {
    public:
     class UnmapFreeMemoryTask;
 
     explicit Unmapper(MemoryAllocator* allocator)
         : allocator_(allocator),
           pending_unmapping_tasks_semaphore_(0),
@@ skipping 74 matching lines @@
     friend class MemoryAllocator;
   };
 
   enum AllocationMode {
     kRegular,
     kPooled,
   };
 
   enum FreeMode {
     kFull,
+    kAlreadyPooled,
     kPreFreeAndQueue,
     kPooledAndQueue,
   };
 
   static size_t CodePageGuardStartOffset();
 
   static size_t CodePageGuardSize();
 
   static size_t CodePageAreaStartOffset();
 
@@ skipping 436 matching lines @@
 // 11-31 words (tiny): The tiny blocks are only used for allocation, when
 //   categories >= small do not have entries anymore.
 // 32-255 words (small): Used for allocating free space between 1-31 words in
 //   size.
 // 256-2047 words (medium): Used for allocating free space between 32-255 words
 //   in size.
 // 1048-16383 words (large): Used for allocating free space between 256-2047
 //   words in size.
 // At least 16384 words (huge): This list is for objects of 2048 words or
 //   larger. Empty pages are also added to this list.
-class FreeList {
+class V8_EXPORT_PRIVATE FreeList {
  public:
   // This method returns how much memory can be allocated after freeing
   // maximum_freed memory.
   static inline size_t GuaranteedAllocatable(size_t maximum_freed) {
     if (maximum_freed <= kTiniestListMax) {
       // Since we are not iterating over all list entries, we cannot guarantee
       // that we can find the maximum freed block in that free list.
       return 0;
     } else if (maximum_freed <= kTinyListMax) {
       return kTinyAllocationMax;
@@ skipping 216 matching lines @@
 
  private:
   LocalAllocationBuffer(Heap* heap, AllocationInfo allocation_info);
 
   void Close();
 
   Heap* heap_;
   AllocationInfo allocation_info_;
 };
 
-class PagedSpace : public Space {
+class V8_EXPORT_PRIVATE PagedSpace : public Space {
  public:
   typedef PageIterator iterator;
 
   static const intptr_t kCompactionMemoryWanted = 500 * KB;
 
   // Creates a space with an id.
   PagedSpace(Heap* heap, AllocationSpace id, Executability executable);
 
   ~PagedSpace() override { TearDown(); }
 
@@ skipping 998 matching lines @@
   PageIterator old_iterator_;
   PageIterator code_iterator_;
   PageIterator map_iterator_;
   LargePageIterator lo_iterator_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_SPACES_H_