Reland "Merge old data and pointer space."

src/heap/heap-inl.h

 // 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.
 
 #ifndef V8_HEAP_HEAP_INL_H_
 #define V8_HEAP_HEAP_INL_H_
 
 #include <cmath>
 
 #include "src/base/platform/platform.h"
@@ skipping 63 matching lines @@
   return AllocateInternalizedStringImpl<false>(t, chars, hash_field);
 }
 
 
 AllocationResult Heap::AllocateOneByteInternalizedString(
     Vector<const uint8_t> str, uint32_t hash_field) {
   CHECK_GE(String::kMaxLength, str.length());
   // Compute map and object size.
   Map* map = one_byte_internalized_string_map();
   int size = SeqOneByteString::SizeFor(str.length());
-  AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
+  AllocationSpace space = SelectSpace(size, TENURED);
 
   // Allocate string.
   HeapObject* result;
   {
-    AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+    AllocationResult allocation = AllocateRaw(size, space, OLD_SPACE);
     if (!allocation.To(&result)) return allocation;
   }
 
   // String maps are all immortal immovable objects.
   result->set_map_no_write_barrier(map);
   // Set length and hash fields of the allocated string.
   String* answer = String::cast(result);
   answer->set_length(str.length());
   answer->set_hash_field(hash_field);
 
   DCHECK_EQ(size, answer->Size());
 
   // Fill in the characters.
   MemCopy(answer->address() + SeqOneByteString::kHeaderSize, str.start(),
           str.length());
 
   return answer;
 }
 
 
 AllocationResult Heap::AllocateTwoByteInternalizedString(Vector<const uc16> str,
                                                          uint32_t hash_field) {
   CHECK_GE(String::kMaxLength, str.length());
   // Compute map and object size.
   Map* map = internalized_string_map();
   int size = SeqTwoByteString::SizeFor(str.length());
-  AllocationSpace space = SelectSpace(size, OLD_DATA_SPACE, TENURED);
+  AllocationSpace space = SelectSpace(size, TENURED);
 
   // Allocate string.
   HeapObject* result;
   {
-    AllocationResult allocation = AllocateRaw(size, space, OLD_DATA_SPACE);
+    AllocationResult allocation = AllocateRaw(size, space, OLD_SPACE);
     if (!allocation.To(&result)) return allocation;
   }
 
   result->set_map(map);
   // Set length and hash fields of the allocated string.
   String* answer = String::cast(result);
   answer->set_length(str.length());
   answer->set_hash_field(hash_field);
 
   DCHECK_EQ(size, answer->Size());
@@ skipping 44 matching lines @@
     if (always_allocate() && allocation.IsRetry() && retry_space != NEW_SPACE) {
       space = retry_space;
     } else {
       if (allocation.To(&object)) {
         OnAllocationEvent(object, size_in_bytes);
       }
       return allocation;
     }
   }
 
-  if (OLD_POINTER_SPACE == space) {
-    allocation = old_pointer_space_->AllocateRaw(size_in_bytes);
-  } else if (OLD_DATA_SPACE == space) {
-    allocation = old_data_space_->AllocateRaw(size_in_bytes);
+  if (OLD_SPACE == space) {
+    allocation = old_space_->AllocateRaw(size_in_bytes);
   } else if (CODE_SPACE == space) {
     if (size_in_bytes <= code_space()->AreaSize()) {
       allocation = code_space_->AllocateRaw(size_in_bytes);
     } else {
       // Large code objects are allocated in large object space.
       allocation = lo_space_->AllocateRaw(size_in_bytes, EXECUTABLE);
     }
   } else if (LO_SPACE == space) {
     allocation = lo_space_->AllocateRaw(size_in_bytes, NOT_EXECUTABLE);
   } else if (CELL_SPACE == space) {
@@ skipping 120 matching lines @@
 bool Heap::InFromSpace(Object* object) {
   return new_space_.FromSpaceContains(object);
 }
 
 
 bool Heap::InToSpace(Object* object) {
   return new_space_.ToSpaceContains(object);
 }
 
 
-bool Heap::InOldPointerSpace(Address address) {
-  return old_pointer_space_->Contains(address);
+bool Heap::InOldSpace(Address address) { return old_space_->Contains(address); }
+
+
+bool Heap::InOldSpace(Object* object) {
+  return InOldSpace(reinterpret_cast<Address>(object));
 }
 
 
-bool Heap::InOldPointerSpace(Object* object) {
-  return InOldPointerSpace(reinterpret_cast<Address>(object));
-}
-
-
-bool Heap::InOldDataSpace(Address address) {
-  return old_data_space_->Contains(address);
-}
-
-
-bool Heap::InOldDataSpace(Object* object) {
-  return InOldDataSpace(reinterpret_cast<Address>(object));
-}
-
-
 bool Heap::OldGenerationAllocationLimitReached() {
   if (!incremental_marking()->IsStopped()) return false;
   return OldGenerationSpaceAvailable() < 0;
 }
 
 
 bool Heap::ShouldBePromoted(Address old_address, int object_size) {
   NewSpacePage* page = NewSpacePage::FromAddress(old_address);
   Address age_mark = new_space_.age_mark();
   return page->IsFlagSet(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK) &&
          (!page->ContainsLimit(age_mark) || old_address < age_mark);
 }
 
 
 void Heap::RecordWrite(Address address, int offset) {
   if (!InNewSpace(address)) store_buffer_.Mark(address + offset);
 }
 
 
 void Heap::RecordWrites(Address address, int start, int len) {
   if (!InNewSpace(address)) {
     for (int i = 0; i < len; i++) {
       store_buffer_.Mark(address + start + i * kPointerSize);
     }
   }
 }
 
 
-OldSpace* Heap::TargetSpace(HeapObject* object) {
-  InstanceType type = object->map()->instance_type();
-  AllocationSpace space = TargetSpaceId(type);
-  return (space == OLD_POINTER_SPACE) ? old_pointer_space_ : old_data_space_;
-}
-
-
-AllocationSpace Heap::TargetSpaceId(InstanceType type) {
-  // Heap numbers and sequential strings are promoted to old data space, all
-  // other object types are promoted to old pointer space.  We do not use
-  // object->IsHeapNumber() and object->IsSeqString() because we already
-  // know that object has the heap object tag.
-
-  // These objects are never allocated in new space.
-  DCHECK(type != MAP_TYPE);
-  DCHECK(type != CODE_TYPE);
-  DCHECK(type != ODDBALL_TYPE);
-  DCHECK(type != CELL_TYPE);
-
-  if (type <= LAST_NAME_TYPE) {
-    if (type == SYMBOL_TYPE) return OLD_POINTER_SPACE;
-    DCHECK(type < FIRST_NONSTRING_TYPE);
-    // There are four string representations: sequential strings, external
-    // strings, cons strings, and sliced strings.
-    // Only the latter two contain non-map-word pointers to heap objects.
-    return ((type & kIsIndirectStringMask) == kIsIndirectStringTag)
-               ? OLD_POINTER_SPACE
-               : OLD_DATA_SPACE;
-  } else {
-    return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
-  }
-}
-
-
 bool Heap::AllowedToBeMigrated(HeapObject* obj, AllocationSpace dst) {
   // Object migration is governed by the following rules:
   //
-  // 1) Objects in new-space can be migrated to one of the old spaces
+  // 1) Objects in new-space can be migrated to the old space
   //    that matches their target space or they stay in new-space.
   // 2) Objects in old-space stay in the same space when migrating.
   // 3) Fillers (two or more words) can migrate due to left-trimming of
-  //    fixed arrays in new-space, old-data-space and old-pointer-space.
+  //    fixed arrays in new-space or old space.
   // 4) Fillers (one word) can never migrate, they are skipped by
   //    incremental marking explicitly to prevent invalid pattern.
-  // 5) Short external strings can end up in old pointer space when a cons
-  //    string in old pointer space is made external (String::MakeExternal).
   //
   // Since this function is used for debugging only, we do not place
   // asserts here, but check everything explicitly.
   if (obj->map() == one_pointer_filler_map()) return false;
   InstanceType type = obj->map()->instance_type();
   MemoryChunk* chunk = MemoryChunk::FromAddress(obj->address());
   AllocationSpace src = chunk->owner()->identity();
   switch (src) {
     case NEW_SPACE:
-      return dst == src || dst == TargetSpaceId(type);
-    case OLD_POINTER_SPACE:
-      return dst == src && (dst == TargetSpaceId(type) || obj->IsFiller() ||
-                            obj->IsExternalString());
-    case OLD_DATA_SPACE:
-      return dst == src && dst == TargetSpaceId(type);
+      return dst == src || dst == OLD_SPACE;
+    case OLD_SPACE:
+      return dst == src &&
+             (dst == OLD_SPACE || obj->IsFiller() || obj->IsExternalString());
     case CODE_SPACE:
       return dst == src && type == CODE_TYPE;
     case MAP_SPACE:
     case CELL_SPACE:
     case LO_SPACE:
       return false;
   }
   UNREACHABLE();
   return false;
 }
@@ skipping 284 matching lines @@
 
 void VerifySmisVisitor::VisitPointers(Object** start, Object** end) {
   for (Object** current = start; current < end; current++) {
     CHECK((*current)->IsSmi());
   }
 }
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_INL_H_