duke@435: /*
xdono@631:  * Copyright 2000-2008 Sun Microsystems, Inc.  All Rights Reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: // This kind of "BarrierSet" allows a "CollectedHeap" to detect and
duke@435: // enumerate ref fields that have been modified (since the last
duke@435: // enumeration), using a card table.
duke@435: 
duke@435: class OopClosure;
duke@435: class Generation;
duke@435: 
duke@435: class ModRefBarrierSet: public BarrierSet {
duke@435: public:
ysr@777: 
ysr@777:   ModRefBarrierSet() { _kind = BarrierSet::ModRef; }
ysr@777: 
ysr@777:   bool is_a(BarrierSet::Name bsn) {
ysr@777:     return bsn == BarrierSet::ModRef;
ysr@777:   }
ysr@777: 
duke@435:   // Barriers only on ref writes.
duke@435:   bool has_read_ref_barrier() { return false; }
duke@435:   bool has_read_prim_barrier() { return false; }
duke@435:   bool has_write_ref_barrier() { return true; }
duke@435:   bool has_write_prim_barrier() { return false; }
duke@435: 
coleenp@548:   bool read_ref_needs_barrier(void* field) { return false; }
duke@435:   bool read_prim_needs_barrier(HeapWord* field, size_t bytes) { return false; }
coleenp@548:   virtual bool write_ref_needs_barrier(void* field, oop new_val) = 0;
duke@435:   bool write_prim_needs_barrier(HeapWord* field, size_t bytes,
duke@435:                                 juint val1, juint val2) { return false; }
duke@435: 
duke@435:   void write_prim_field(oop obj, size_t offset, size_t bytes,
duke@435:                         juint val1, juint val2) {}
duke@435: 
coleenp@548:   void read_ref_field(void* field) {}
duke@435:   void read_prim_field(HeapWord* field, size_t bytes) {}
duke@435: protected:
coleenp@548:   virtual void write_ref_field_work(void* field, oop new_val) = 0;
duke@435: public:
duke@435:   void write_prim_field(HeapWord* field, size_t bytes,
duke@435:                         juint val1, juint val2) {}
duke@435: 
duke@435:   bool has_read_ref_array_opt() { return false; }
duke@435:   bool has_read_prim_array_opt() { return false; }
duke@435:   bool has_write_prim_array_opt() { return false; }
duke@435: 
duke@435:   bool has_read_region_opt() { return false; }
duke@435: 
duke@435: 
duke@435:   // These operations should assert false unless the correponding operation
duke@435:   // above returns true.
duke@435:   void read_ref_array(MemRegion mr) {
duke@435:     assert(false, "can't call");
duke@435:   }
duke@435:   void read_prim_array(MemRegion mr) {
duke@435:     assert(false, "can't call");
duke@435:   }
duke@435:   void write_prim_array(MemRegion mr) {
duke@435:     assert(false, "can't call");
duke@435:   }
duke@435:   void read_region(MemRegion mr) {
duke@435:     assert(false, "can't call");
duke@435:   }
duke@435: 
duke@435:   // Invoke "cl->do_oop" on (the address of) every possibly-modifed
duke@435:   // reference field in objects in "sp".  If "clear" is "true", the oops
duke@435:   // are no longer considered possibly modified after application of the
duke@435:   // closure.  If' "before_save_marks" is true, oops in objects allocated
duke@435:   // after the last call to "save_marks" on "sp" will not be considered.
duke@435:   virtual void mod_oop_in_space_iterate(Space* sp, OopClosure* cl,
duke@435:                                         bool clear = false,
duke@435:                                         bool before_save_marks = false) = 0;
duke@435: 
ysr@777:   // Causes all refs in "mr" to be assumed to be modified.  If "whole_heap"
ysr@777:   // is true, the caller asserts that the entire heap is being invalidated,
ysr@777:   // which may admit an optimized implementation for some barriers.
ysr@777:   virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0;
duke@435: 
duke@435:   // The caller guarantees that "mr" contains no references.  (Perhaps it's
duke@435:   // objects have been moved elsewhere.)
duke@435:   virtual void clear(MemRegion mr) = 0;
duke@435: 
duke@435:   // Pass along the argument to the superclass.
duke@435:   ModRefBarrierSet(int max_covered_regions) :
duke@435:     BarrierSet(max_covered_regions) {}
duke@435: 
duke@435: #ifndef PRODUCT
duke@435:   // Verifies that the given region contains no modified references.
duke@435:   virtual void verify_clean_region(MemRegion mr) = 0;
duke@435: #endif
duke@435: 
duke@435: };