Reland "Only use FreeSpace objects in the free list"

src/heap/heap.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/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 477 matching lines @@
     Code* code = Code::cast(object);
     Code::Kind current_kind = code->kind();
     if (current_kind == Code::FUNCTION ||
         current_kind == Code::OPTIMIZED_FUNCTION) {
       code->ClearInlineCaches(kind);
     }
   }
 }
 
 
-void Heap::RepairFreeListsAfterBoot() {
+void Heap::RepairFreeListsAfterDeserialization() {
   PagedSpaces spaces(this);
   for (PagedSpace* space = spaces.next(); space != NULL;
        space = spaces.next()) {
-    space->RepairFreeListsAfterBoot();
+    space->RepairFreeListsAfterDeserialization();
   }
 }
 
 
 void Heap::ProcessPretenuringFeedback() {
   if (FLAG_allocation_site_pretenuring) {
     int tenure_decisions = 0;
     int dont_tenure_decisions = 0;
     int allocation_mementos_found = 0;
     int allocation_sites = 0;
@@ skipping 432 matching lines @@
         for (auto& chunk : *reservation) {
           AllocationResult allocation;
           int size = chunk.size;
           DCHECK_LE(size, MemoryAllocator::PageAreaSize(
                               static_cast<AllocationSpace>(space)));
           if (space == NEW_SPACE) {
             allocation = new_space()->AllocateRaw(size);
           } else {
             allocation = paged_space(space)->AllocateRaw(size);
           }
-          FreeListNode* node;
-          if (allocation.To(&node)) {
+          HeapObject* free_space;
+          if (allocation.To(&free_space)) {
             // Mark with a free list node, in case we have a GC before
             // deserializing.
-            node->set_size(this, size);
+            Address free_space_address = free_space->address();
+            CreateFillerObjectAt(free_space_address, size);
             DCHECK(space < Serializer::kNumberOfPreallocatedSpaces);
-            chunk.start = node->address();
-            chunk.end = node->address() + size;
+            chunk.start = free_space_address;
+            chunk.end = free_space_address + size;
           } else {
             perform_gc = true;
             break;
           }
         }
       }
       if (perform_gc) {
         if (space == NEW_SPACE) {
           CollectGarbage(NEW_SPACE, "failed to reserve space in the new space");
         } else {
@@ skipping 2412 matching lines @@
 
   result->set_map_no_write_barrier(byte_array_map());
   ByteArray::cast(result)->set_length(length);
   return result;
 }
 
 
 void Heap::CreateFillerObjectAt(Address addr, int size) {
   if (size == 0) return;
   HeapObject* filler = HeapObject::FromAddress(addr);
+  // At this point, we may be deserializing the heap from a snapshot, and
+  // none of the maps have been created yet and are NULL.
   if (size == kPointerSize) {
-    filler->set_map_no_write_barrier(one_pointer_filler_map());
+    filler->set_map_no_write_barrier(raw_unchecked_one_pointer_filler_map());
+    DCHECK(filler->map() == NULL || filler->map() == one_pointer_filler_map());
   } else if (size == 2 * kPointerSize) {
-    filler->set_map_no_write_barrier(two_pointer_filler_map());
+    filler->set_map_no_write_barrier(raw_unchecked_two_pointer_filler_map());
+    DCHECK(filler->map() == NULL || filler->map() == two_pointer_filler_map());
   } else {
-    filler->set_map_no_write_barrier(free_space_map());
-    FreeSpace::cast(filler)->set_size(size);
+    filler->set_map_no_write_barrier(raw_unchecked_free_space_map());
+    DCHECK(filler->map() == NULL || filler->map() == free_space_map());
+    FreeSpace::cast(filler)->nobarrier_set_size(size);
   }
 }
 
 
 bool Heap::CanMoveObjectStart(HeapObject* object) {
   Address address = object->address();
   bool is_in_old_pointer_space = InOldPointerSpace(address);
   bool is_in_old_data_space = InOldDataSpace(address);
 
   if (lo_space()->Contains(object)) return false;
@@ skipping 3027 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal