GC branch: Some changes to make V8 work with different page sizes.

src/spaces.cc

 // Copyright 2011 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 710 matching lines @@
     Address cur = obj->address();
     Address next = cur + obj->Size();
     if ((cur <= addr) && (addr < next)) return obj;
   }
 
   UNREACHABLE();
   return Failure::Exception();
 }
 
 
-void PagedSpace::SetAllocationInfo(Address top, Address limit) {
-  Free(allocation_info_.top, allocation_info_.limit - allocation_info_.top);
-  allocation_info_.top = top;
-  allocation_info_.limit = limit;
-  ASSERT(allocation_info_.VerifyPagedAllocation());
-}
-
-
 bool PagedSpace::Expand() {
   ASSERT(max_capacity_ % Page::kObjectAreaSize == 0);
   ASSERT(Capacity() % Page::kObjectAreaSize == 0);
 
   if (Capacity() == max_capacity_) return false;
 
   ASSERT(Capacity() < max_capacity_);
 
   // Are we going to exceed capacity for this space?
   if ((Capacity() + Page::kPageSize) > max_capacity_) return false;
@@ skipping 301 matching lines @@
   Address current = page->body();
   CHECK_EQ(current, to_space_.space_low());
 
   while (current != top()) {
     if (current == page->body_limit()) {
       // At end of page, switch to next page.
       page = page->next_page();
       // Next page should be valid.
       CHECK(!page->is_anchor());
       current = page->body();
+      continue;

[Vyacheslav Egorov (Chromium), 2011/06/14 10:59:09]

I do not think this is necessary.

[Erik Corry, 2011/06/14 18:51:21]

It made a bug go away for me.

If the last object on the previous page goes right up to the limit and there are
no objects on the second page then it goes wrong without this line.

[Lasse Reichstein, 2011/06/15 06:56:27]

It should be there.
There is nothing preventing top() from being either at the end of one page or at
the beginning of the next page, effectively representing the same location. This
tests both.

It's likely that both cases don't occur at the same places, e.g., that we
advance to the next page when possible, but on the very last page of the space,
we stay at the end of the page. But there is no invariant saying what we do, so
we should handle both possibilities in all cases.

     }
     // The allocation pointer should not be in the middle of an object.
     CHECK(!page->ContainsLimit(top()) || current < top());
 
     HeapObject* object = HeapObject::FromAddress(current);
 
     // The first word should be a map, and we expect all map pointers to
     // be in map space.
     Map* map = object->map();
     CHECK(map->IsMap());
@@ skipping 1358 matching lines @@
   for (HeapObject* obj = obj_it.Next(); obj != NULL; obj = obj_it.Next()) {
     if (obj->IsCode()) {
       Code* code = Code::cast(obj);
       isolate->code_kind_statistics()[code->kind()] += code->Size();
     }
   }
 }
 #endif  // DEBUG
 
 } }  // namespace v8::internal