aoqi@0: /*
aoqi@0:  * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  *
aoqi@0:  */
aoqi@0: 
aoqi@0: #ifndef SHARE_VM_MEMORY_MEMREGION_HPP
aoqi@0: #define SHARE_VM_MEMORY_MEMREGION_HPP
aoqi@0: 
aoqi@0: #include "memory/allocation.hpp"
aoqi@0: #include "utilities/debug.hpp"
aoqi@0: #include "utilities/globalDefinitions.hpp"
aoqi@0: 
aoqi@0: // A very simple data structure representing a contigous region
aoqi@0: // region of address space.
aoqi@0: 
aoqi@0: // Note that MemRegions are passed by value, not by reference.
aoqi@0: // The intent is that they remain very small and contain no
aoqi@0: // objects. _ValueObj should never be allocated in heap but we do
aoqi@0: // create MemRegions (in CardTableModRefBS) in heap so operator
aoqi@0: // new and operator new [] added for this special case.
aoqi@0: 
aoqi@0: class MetaWord;
aoqi@0: 
aoqi@0: class MemRegion VALUE_OBJ_CLASS_SPEC {
aoqi@0:   friend class VMStructs;
aoqi@0: private:
aoqi@0:   HeapWord* _start;
aoqi@0:   size_t    _word_size;
aoqi@0: 
aoqi@0: public:
aoqi@0:   MemRegion() : _start(NULL), _word_size(0) {};
aoqi@0:   MemRegion(HeapWord* start, size_t word_size) :
aoqi@0:     _start(start), _word_size(word_size) {};
aoqi@0:   MemRegion(HeapWord* start, HeapWord* end) :
aoqi@0:     _start(start), _word_size(pointer_delta(end, start)) {
aoqi@0:     assert(end >= start, "incorrect constructor arguments");
aoqi@0:   }
aoqi@0:   MemRegion(MetaWord* start, MetaWord* end) :
aoqi@0:     _start((HeapWord*)start), _word_size(pointer_delta(end, start)) {
aoqi@0:     assert(end >= start, "incorrect constructor arguments");
aoqi@0:   }
aoqi@0: 
aoqi@0:   MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
aoqi@0: 
aoqi@0:   MemRegion intersection(const MemRegion mr2) const;
aoqi@0:   // regions must overlap or be adjacent
aoqi@0:   MemRegion _union(const MemRegion mr2) const;
aoqi@0:   // minus will fail a guarantee if mr2 is interior to this,
aoqi@0:   // since there's no way to return 2 disjoint regions.
aoqi@0:   MemRegion minus(const MemRegion mr2) const;
aoqi@0: 
aoqi@0:   HeapWord* start() const { return _start; }
aoqi@0:   HeapWord* end() const   { return _start + _word_size; }
aoqi@0:   HeapWord* last() const  { return _start + _word_size - 1; }
aoqi@0: 
aoqi@0:   void set_start(HeapWord* start) { _start = start; }
aoqi@0:   void set_end(HeapWord* end)     { _word_size = pointer_delta(end, _start); }
aoqi@0:   void set_word_size(size_t word_size) {
aoqi@0:     _word_size = word_size;
aoqi@0:   }
aoqi@0: 
aoqi@0:   bool contains(const MemRegion mr2) const {
aoqi@0:     return _start <= mr2._start && end() >= mr2.end();
aoqi@0:   }
aoqi@0:   bool contains(const void* addr) const {
aoqi@0:     return addr >= (void*)_start && addr < (void*)end();
aoqi@0:   }
aoqi@0:   bool equals(const MemRegion mr2) const {
aoqi@0:     // first disjunct since we do not have a canonical empty set
aoqi@0:     return ((is_empty() && mr2.is_empty()) ||
aoqi@0:             (start() == mr2.start() && end() == mr2.end()));
aoqi@0:   }
aoqi@0: 
aoqi@0:   size_t byte_size() const { return _word_size * sizeof(HeapWord); }
aoqi@0:   size_t word_size() const { return _word_size; }
aoqi@0: 
aoqi@0:   bool is_empty() const { return word_size() == 0; }
aoqi@0:   void* operator new(size_t size) throw();
aoqi@0:   void* operator new [](size_t size) throw();
aoqi@0:   void  operator delete(void* p);
aoqi@0:   void  operator delete [](void* p);
aoqi@0: };
aoqi@0: 
aoqi@0: // For iteration over MemRegion's.
aoqi@0: 
aoqi@0: class MemRegionClosure : public StackObj {
aoqi@0: public:
aoqi@0:   virtual void do_MemRegion(MemRegion mr) = 0;
aoqi@0: };
aoqi@0: 
aoqi@0: // A ResourceObj version of MemRegionClosure
aoqi@0: 
aoqi@0: class MemRegionClosureRO: public MemRegionClosure {
aoqi@0: public:
aoqi@0:   void* operator new(size_t size, ResourceObj::allocation_type type, MEMFLAGS flags) throw() {
aoqi@0:         return ResourceObj::operator new(size, type, flags);
aoqi@0:   }
aoqi@0:   void* operator new(size_t size, Arena *arena) throw() {
aoqi@0:         return ResourceObj::operator new(size, arena);
aoqi@0:   }
aoqi@0:   void* operator new(size_t size) throw() {
aoqi@0:         return ResourceObj::operator new(size);
aoqi@0:   }
aoqi@0: 
aoqi@0:   void  operator delete(void* p) {} // nothing to do
aoqi@0: };
aoqi@0: 
aoqi@0: #endif // SHARE_VM_MEMORY_MEMREGION_HPP