--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/parallelScavenge/psPromotionLAB.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,142 @@
+/*
+ * Copyright 2002 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+//
+// PSPromotionLAB is a parallel scavenge promotion lab. This class acts very
+// much like a MutableSpace. We couldn't embed a MutableSpace, though, as
+// it has a considerable number of asserts and invariants that are violated.
+//
+
+class ObjectStartArray;
+
+class PSPromotionLAB : public CHeapObj {
+ protected:
+  static const size_t filler_header_size;
+
+  enum LabState {
+    needs_flush,
+    flushed,
+    zero_size
+  };
+
+  HeapWord* _top;
+  HeapWord* _bottom;
+  HeapWord* _end;
+  LabState _state;
+
+  void set_top(HeapWord* value)    { _top = value; }
+  void set_bottom(HeapWord* value) { _bottom = value; }
+  void set_end(HeapWord* value)    { _end = value; }
+
+  // The shared initialize code invokes this.
+  debug_only(virtual bool lab_is_valid(MemRegion lab) { return false; });
+
+  PSPromotionLAB() : _top(NULL), _bottom(NULL), _end(NULL) { }
+
+ public:
+  // Filling and flushing.
+  void initialize(MemRegion lab);
+
+  virtual void flush();
+
+  // Accessors
+  HeapWord* bottom() const           { return _bottom; }
+  HeapWord* end() const              { return _end;    }
+  HeapWord* top() const              { return _top;    }
+
+  bool is_flushed()                  { return _state == flushed; }
+
+  bool unallocate_object(oop obj);
+
+  // Returns a subregion containing all objects in this space.
+  MemRegion used_region()            { return MemRegion(bottom(), top()); }
+
+  // Boolean querries.
+  bool is_empty() const              { return used() == 0; }
+  bool not_empty() const             { return used() > 0; }
+  bool contains(const void* p) const { return _bottom <= p && p < _end; }
+
+  // Size computations.  Sizes are in bytes.
+  size_t capacity() const            { return byte_size(bottom(), end()); }
+  size_t used() const                { return byte_size(bottom(), top()); }
+  size_t free() const                { return byte_size(top(),    end()); }
+};
+
+class PSYoungPromotionLAB : public PSPromotionLAB {
+ public:
+  PSYoungPromotionLAB() { }
+
+  // Not MT safe
+  HeapWord* allocate(size_t size) {
+    // Can't assert this, when young fills, we keep the LAB around, but flushed.
+    // assert(_state != flushed, "Sanity");
+    HeapWord* obj = top();
+    HeapWord* new_top = obj + size;
+    // The 'new_top>obj' check is needed to detect overflow of obj+size.
+    if (new_top > obj && new_top <= end()) {
+      set_top(new_top);
+      assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
+             "checking alignment");
+      return obj;
+    }
+
+    return NULL;
+  }
+
+  debug_only(virtual bool lab_is_valid(MemRegion lab));
+};
+
+class PSOldPromotionLAB : public PSPromotionLAB {
+ private:
+  ObjectStartArray* _start_array;
+
+ public:
+  PSOldPromotionLAB() : _start_array(NULL) { }
+  PSOldPromotionLAB(ObjectStartArray* start_array) : _start_array(start_array) { }
+
+  void set_start_array(ObjectStartArray* start_array) { _start_array = start_array; }
+
+  void flush();
+
+  // Not MT safe
+  HeapWord* allocate(size_t size) {
+    // Cannot test for this now that we're doing promotion failures
+    // assert(_state != flushed, "Sanity");
+    assert(_start_array != NULL, "Sanity");
+    HeapWord* obj = top();
+    HeapWord* new_top = obj + size;
+    // The 'new_top>obj' check is needed to detect overflow of obj+size.
+    if (new_top > obj && new_top <= end()) {
+      set_top(new_top);
+      assert(is_object_aligned((intptr_t)obj) && is_object_aligned((intptr_t)new_top),
+             "checking alignment");
+      _start_array->allocate_block(obj);
+      return obj;
+    }
+
+    return NULL;
+  }
+
+  debug_only(virtual bool lab_is_valid(MemRegion lab));
+};