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src/share/vm/memory/memRegion.hpp@7ae4e26cb1e0 (annotated)

src/share/vm/memory/memRegion.hpp

Thu, 12 Oct 2017 21:27:07 +0800

author

aoqi

date

Thu, 12 Oct 2017 21:27:07 +0800

changeset 7535

7ae4e26cb1e0

parent 6876

710a3c8b516e

permissions

-rw-r--r--

merge

aoqi@0	1	/*
aoqi@0	2	* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
aoqi@0	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0	4	*
aoqi@0	5	* This code is free software; you can redistribute it and/or modify it
aoqi@0	6	* under the terms of the GNU General Public License version 2 only, as
aoqi@0	7	* published by the Free Software Foundation.
aoqi@0	8	*
aoqi@0	9	* This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
aoqi@0	12	* version 2 for more details (a copy is included in the LICENSE file that
aoqi@0	13	* accompanied this code).
aoqi@0	14	*
aoqi@0	15	* You should have received a copy of the GNU General Public License version
aoqi@0	16	* 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0	18	*
aoqi@0	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0	20	* or visit www.oracle.com if you need additional information or have any
aoqi@0	21	* questions.
aoqi@0	22	*
aoqi@0	23	*/
aoqi@0	24
aoqi@0	25	#ifndef SHARE_VM_MEMORY_MEMREGION_HPP
aoqi@0	26	#define SHARE_VM_MEMORY_MEMREGION_HPP
aoqi@0	27
aoqi@0	28	#include "memory/allocation.hpp"
aoqi@0	29	#include "utilities/debug.hpp"
aoqi@0	30	#include "utilities/globalDefinitions.hpp"
aoqi@0	31
aoqi@0	32	// A very simple data structure representing a contigous region
aoqi@0	33	// region of address space.
aoqi@0	34
aoqi@0	35	// Note that MemRegions are passed by value, not by reference.
aoqi@0	36	// The intent is that they remain very small and contain no
aoqi@0	37	// objects. _ValueObj should never be allocated in heap but we do
aoqi@0	38	// create MemRegions (in CardTableModRefBS) in heap so operator
aoqi@0	39	// new and operator new [] added for this special case.
aoqi@0	40
aoqi@0	41	class MetaWord;
aoqi@0	42
aoqi@0	43	class MemRegion VALUE_OBJ_CLASS_SPEC {
aoqi@0	44	friend class VMStructs;
aoqi@0	45	private:
aoqi@0	46	HeapWord* _start;
aoqi@0	47	size_t _word_size;
aoqi@0	48
aoqi@0	49	public:
aoqi@0	50	MemRegion() : _start(NULL), _word_size(0) {};
aoqi@0	51	MemRegion(HeapWord* start, size_t word_size) :
aoqi@0	52	_start(start), _word_size(word_size) {};
aoqi@0	53	MemRegion(HeapWord* start, HeapWord* end) :
aoqi@0	54	_start(start), _word_size(pointer_delta(end, start)) {
aoqi@0	55	assert(end >= start, "incorrect constructor arguments");
aoqi@0	56	}
aoqi@0	57	MemRegion(MetaWord* start, MetaWord* end) :
aoqi@0	58	_start((HeapWord*)start), _word_size(pointer_delta(end, start)) {
aoqi@0	59	assert(end >= start, "incorrect constructor arguments");
aoqi@0	60	}
aoqi@0	61
aoqi@0	62	MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
aoqi@0	63
aoqi@0	64	MemRegion intersection(const MemRegion mr2) const;
aoqi@0	65	// regions must overlap or be adjacent
aoqi@0	66	MemRegion _union(const MemRegion mr2) const;
aoqi@0	67	// minus will fail a guarantee if mr2 is interior to this,
aoqi@0	68	// since there's no way to return 2 disjoint regions.
aoqi@0	69	MemRegion minus(const MemRegion mr2) const;
aoqi@0	70
aoqi@0	71	HeapWord* start() const { return _start; }
aoqi@0	72	HeapWord* end() const { return _start + _word_size; }
aoqi@0	73	HeapWord* last() const { return _start + _word_size - 1; }
aoqi@0	74
aoqi@0	75	void set_start(HeapWord* start) { _start = start; }
aoqi@0	76	void set_end(HeapWord* end) { _word_size = pointer_delta(end, _start); }
aoqi@0	77	void set_word_size(size_t word_size) {
aoqi@0	78	_word_size = word_size;
aoqi@0	79	}
aoqi@0	80
aoqi@0	81	bool contains(const MemRegion mr2) const {
aoqi@0	82	return _start <= mr2._start && end() >= mr2.end();
aoqi@0	83	}
aoqi@0	84	bool contains(const void* addr) const {
aoqi@0	85	return addr >= (void*)_start && addr < (void*)end();
aoqi@0	86	}
aoqi@0	87	bool equals(const MemRegion mr2) const {
aoqi@0	88	// first disjunct since we do not have a canonical empty set
aoqi@0	89	return ((is_empty() && mr2.is_empty()) ||
aoqi@0	90	(start() == mr2.start() && end() == mr2.end()));
aoqi@0	91	}
aoqi@0	92
aoqi@0	93	size_t byte_size() const { return _word_size * sizeof(HeapWord); }
aoqi@0	94	size_t word_size() const { return _word_size; }
aoqi@0	95
aoqi@0	96	bool is_empty() const { return word_size() == 0; }
aoqi@0	97	void* operator new(size_t size) throw();
aoqi@0	98	void* operator new [](size_t size) throw();
aoqi@0	99	void operator delete(void* p);
aoqi@0	100	void operator delete [](void* p);
aoqi@0	101	};
aoqi@0	102
aoqi@0	103	// For iteration over MemRegion's.
aoqi@0	104
aoqi@0	105	class MemRegionClosure : public StackObj {
aoqi@0	106	public:
aoqi@0	107	virtual void do_MemRegion(MemRegion mr) = 0;
aoqi@0	108	};
aoqi@0	109
aoqi@0	110	// A ResourceObj version of MemRegionClosure
aoqi@0	111
aoqi@0	112	class MemRegionClosureRO: public MemRegionClosure {
aoqi@0	113	public:
aoqi@0	114	void* operator new(size_t size, ResourceObj::allocation_type type, MEMFLAGS flags) throw() {
aoqi@0	115	return ResourceObj::operator new(size, type, flags);
aoqi@0	116	}
aoqi@0	117	void* operator new(size_t size, Arena *arena) throw() {
aoqi@0	118	return ResourceObj::operator new(size, arena);
aoqi@0	119	}
aoqi@0	120	void* operator new(size_t size) throw() {
aoqi@0	121	return ResourceObj::operator new(size);
aoqi@0	122	}
aoqi@0	123
aoqi@0	124	void operator delete(void* p) {} // nothing to do
aoqi@0	125	};
aoqi@0	126
aoqi@0	127	#endif // SHARE_VM_MEMORY_MEMREGION_HPP