Cardmarking writebarrier.

src/heap-inl.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 166 matching lines @@
   // - to space is already 25% full.
   return old_address < new_space_.age_mark()
       || (new_space_.Size() + object_size) >= (new_space_.Capacity() >> 2);
 }
 
 
 void Heap::RecordWrite(Address address, int offset) {
   if (new_space_.Contains(address)) return;
   ASSERT(!new_space_.FromSpaceContains(address));
   SLOW_ASSERT(Contains(address + offset));
-  Page::SetRSet(address, offset);
+  Page::FromAddress(address)->MarkRegionDirty(address + offset);
 }
 
 
 void Heap::RecordWrites(Address address, int start, int len) {
   if (new_space_.Contains(address)) return;
   ASSERT(!new_space_.FromSpaceContains(address));
   for (int offset = start;
        offset < start + len * kPointerSize;
        offset += kPointerSize) {
     SLOW_ASSERT(Contains(address + offset));
-    Page::SetRSet(address, offset);
+    Page::FromAddress(address)->MarkRegionDirty(address + offset);
   }
 }
 
 
 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_;
@@ skipping 18 matching lines @@
     // non-map-word pointers to heap objects.
     return ((type & kStringRepresentationMask) == kConsStringTag)
         ? OLD_POINTER_SPACE
         : OLD_DATA_SPACE;
   } else {
     return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
   }
 }
 
 
-void Heap::CopyBlock(Object** dst, Object** src, int byte_size) {
+void Heap::CopyBlock(Address dst, Address src, int byte_size) {
   ASSERT(IsAligned(byte_size, kPointerSize));
-  CopyWords(dst, src, byte_size / kPointerSize);
+  CopyWords(reinterpret_cast<Object**>(dst),
+            reinterpret_cast<Object**>(src),
+            byte_size / kPointerSize);
 }
 
 
-void Heap::MoveBlock(Object** dst, Object** src, int byte_size) {
+void Heap::CopyBlockToOldSpaceAndUpdateRegionMarks(Address dst,
+                                                   Address src,
+                                                   int byte_size) {
+  ASSERT(IsAligned(byte_size, kPointerSize));
+
+  Page* page = Page::FromAddress(dst);
+  uint32_t marks = page->GetRegionMarks();
+
+  for (int remaining = byte_size / kPointerSize;
+       remaining > 0;
+       remaining--) {
+    Memory::Object_at(dst) = Memory::Object_at(src);
+
+    if (Heap::InNewSpace(Memory::Object_at(dst))) {
+      marks |= page->GetRegionMaskForAddress(dst);
+    }
+
+    dst += kPointerSize;
+    src += kPointerSize;
+  }
+
+  page->SetRegionMarks(marks);
+}
+
+
+void Heap::MoveBlock(Address dst, Address src, int byte_size) {
   ASSERT(IsAligned(byte_size, kPointerSize));
 
   int size_in_words = byte_size / kPointerSize;
 
   if ((dst < src) || (dst >= (src + size_in_words))) {
     ASSERT((dst >= (src + size_in_words)) ||
            ((OffsetFrom(reinterpret_cast<Address>(src)) -
              OffsetFrom(reinterpret_cast<Address>(dst))) >= kPointerSize));
 
-    Object** end = src + size_in_words;
+    Object** src_slot = reinterpret_cast<Object**>(src);
+    Object** dst_slot = reinterpret_cast<Object**>(dst);
+    Object** end_slot = src_slot + size_in_words;
 
-    while (src != end) {
-      *dst++ = *src++;
+    while (src_slot != end_slot) {
+      *dst_slot++ = *src_slot++;
     }
   } else {
     memmove(dst, src, byte_size);
   }
 }
 
 
+void Heap::MoveBlockToOldSpaceAndUpdateRegionMarks(Address dst,
+                                                   Address src,
+                                                   int byte_size) {
+  ASSERT(IsAligned(byte_size, kPointerSize));
+  ASSERT((dst >= (src + byte_size)) ||
+         ((OffsetFrom(src) - OffsetFrom(dst)) >= kPointerSize));
+
+  CopyBlockToOldSpaceAndUpdateRegionMarks(dst, src, byte_size);
+}
+
+
 void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
   ASSERT(InFromSpace(object));
 
   // We use the first word (where the map pointer usually is) of a heap
   // object to record the forwarding pointer.  A forwarding pointer can
   // point to an old space, the code space, or the to space of the new
   // generation.
   MapWord first_word = object->map_word();
 
   // If the first word is a forwarding address, the object has already been
@@ skipping 168 matching lines @@
 
 
 void ExternalStringTable::ShrinkNewStrings(int position) {
   new_space_strings_.Rewind(position);
   Verify();
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_INL_H_