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/*
* Copyright 2001-2008 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.
*
*/
// A GenRemSet provides ways of iterating over pointers accross generations.
// (This is especially useful for older-to-younger.)
class Generation;
class BarrierSet;
class OopsInGenClosure;
class CardTableRS;
class GenRemSet: public CHeapObj {
friend class Generation;
BarrierSet* _bs;
public:
enum Name {
CardTable,
Other
};
GenRemSet(BarrierSet * bs) : _bs(bs) {}
virtual Name rs_kind() = 0;
// These are for dynamic downcasts. Unfortunately that it names the
// possible subtypes (but not that they are subtypes!) Return NULL if
// the cast is invalide.
virtual CardTableRS* as_CardTableRS() { return NULL; }
// Return the barrier set associated with "this."
BarrierSet* bs() { return _bs; }
// Do any (sequential) processing necessary to prepare for (possibly
// "parallel", if that arg is true) calls to younger_refs_iterate.
virtual void prepare_for_younger_refs_iterate(bool parallel) = 0;
// Apply the "do_oop" method of "blk" to (exactly) all oop locations
// 1) that are in objects allocated in "g" at the time of the last call
// to "save_Marks", and
// 2) that point to objects in younger generations.
virtual void younger_refs_iterate(Generation* g, OopsInGenClosure* blk) = 0;
virtual void younger_refs_in_space_iterate(Space* sp,
OopsInGenClosure* cl) = 0;
// This method is used to notify the remembered set that "new_val" has
// been written into "field" by the garbage collector.
void write_ref_field_gc(void* field, oop new_val);
protected:
virtual void write_ref_field_gc_work(void* field, oop new_val) = 0;
public:
// A version of the above suitable for use by parallel collectors.
virtual void write_ref_field_gc_par(void* field, oop new_val) = 0;
// Resize one of the regions covered by the remembered set.
virtual void resize_covered_region(MemRegion new_region) = 0;
// If the rem set imposes any alignment restrictions on boundaries
// within the heap, this function tells whether they are met.
virtual bool is_aligned(HeapWord* addr) = 0;
// If the RS (or BS) imposes an aligment constraint on maximum heap size.
// (This must be static, and dispatch on "nm", because it is called
// before an RS is created.)
static uintx max_alignment_constraint(Name nm);
virtual void verify() = 0;
// Verify that the remembered set has no entries for
// the heap interval denoted by mr. If there are any
// alignment constraints on the remembered set, only the
// part of the region that is aligned is checked.
//
// alignment boundaries
// +--------+-------+--------+-------+
// [ region mr )
// [ part checked )
virtual void verify_aligned_region_empty(MemRegion mr) = 0;
// If appropriate, print some information about the remset on "tty".
virtual void print() {}
// Informs the RS that the given memregion contains no references to
// younger generations.
virtual void clear(MemRegion mr) = 0;
// Informs the RS that there are no references to generations
// younger than gen from generations gen and older.
// The parameter clear_perm indicates if the perm_gen's
// remembered set should also be processed/cleared.
virtual void clear_into_younger(Generation* gen, bool clear_perm) = 0;
// Informs the RS that refs in the given "mr" may have changed
// arbitrarily, and therefore may contain old-to-young pointers.
virtual void invalidate(MemRegion mr) = 0;
// Informs the RS that refs in this generation
// may have changed arbitrarily, and therefore may contain
// old-to-young pointers in arbitrary locations. The parameter
// younger indicates if the same should be done for younger generations
// as well. The parameter perm indicates if the same should be done for
// perm gen as well.
virtual void invalidate_or_clear(Generation* gen, bool younger, bool perm) = 0;
};
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