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src/share/vm/memory/memRegion.hpp@e9ff18c4ace7 (annotated)

src/share/vm/memory/memRegion.hpp

Wed, 02 Jun 2010 22:45:42 -0700

author

jrose

date

Wed, 02 Jun 2010 22:45:42 -0700

changeset 1934

e9ff18c4ace7

parent 1907

c18cbe5936b8

child 2314

f95d63e2154a

permissions

-rw-r--r--

Merge

duke@435	1	/*
trims@1907	2	* Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// A very simple data structure representing a contigous region
duke@435	26	// region of address space.
duke@435	27
duke@435	28	// Note that MemRegions are passed by value, not by reference.
duke@435	29	// The intent is that they remain very small and contain no
duke@435	30	// objects.
duke@435	31
duke@435	32	class MemRegion VALUE_OBJ_CLASS_SPEC {
duke@435	33	friend class VMStructs;
duke@435	34	private:
duke@435	35	HeapWord* _start;
duke@435	36	size_t _word_size;
duke@435	37
duke@435	38	public:
duke@435	39	MemRegion() : _start(NULL), _word_size(0) {};
duke@435	40	MemRegion(HeapWord* start, size_t word_size) :
duke@435	41	_start(start), _word_size(word_size) {};
duke@435	42	MemRegion(HeapWord* start, HeapWord* end) :
duke@435	43	_start(start), _word_size(pointer_delta(end, start)) {
duke@435	44	assert(end >= start, "incorrect constructor arguments");
duke@435	45	}
duke@435	46
duke@435	47	MemRegion(const MemRegion& mr): _start(mr._start), _word_size(mr._word_size) {}
duke@435	48
duke@435	49	MemRegion intersection(const MemRegion mr2) const;
duke@435	50	// regions must overlap or be adjacent
duke@435	51	MemRegion _union(const MemRegion mr2) const;
duke@435	52	// minus will fail a guarantee if mr2 is interior to this,
duke@435	53	// since there's no way to return 2 disjoint regions.
duke@435	54	MemRegion minus(const MemRegion mr2) const;
duke@435	55
duke@435	56	HeapWord* start() const { return _start; }
duke@435	57	HeapWord* end() const { return _start + _word_size; }
duke@435	58	HeapWord* last() const { return _start + _word_size - 1; }
duke@435	59
duke@435	60	void set_start(HeapWord* start) { _start = start; }
duke@435	61	void set_end(HeapWord* end) { _word_size = pointer_delta(end, _start); }
duke@435	62	void set_word_size(size_t word_size) {
duke@435	63	_word_size = word_size;
duke@435	64	}
duke@435	65
duke@435	66	bool contains(const MemRegion mr2) const {
duke@435	67	return _start <= mr2._start && end() >= mr2.end();
duke@435	68	}
duke@435	69	bool contains(const void* addr) const {
duke@435	70	return addr >= (void*)_start && addr < (void*)end();
duke@435	71	}
duke@435	72	bool equals(const MemRegion mr2) const {
duke@435	73	// first disjunct since we do not have a canonical empty set
duke@435	74	return ((is_empty() && mr2.is_empty()) ||
duke@435	75	(start() == mr2.start() && end() == mr2.end()));
duke@435	76	}
duke@435	77
duke@435	78	size_t byte_size() const { return _word_size * sizeof(HeapWord); }
duke@435	79	size_t word_size() const { return _word_size; }
duke@435	80
duke@435	81	bool is_empty() const { return word_size() == 0; }
duke@435	82	};
duke@435	83
duke@435	84	// For iteration over MemRegion's.
duke@435	85
duke@435	86	class MemRegionClosure : public StackObj {
duke@435	87	public:
duke@435	88	virtual void do_MemRegion(MemRegion mr) = 0;
duke@435	89	};
duke@435	90
duke@435	91	// A ResourceObj version of MemRegionClosure
duke@435	92
duke@435	93	class MemRegionClosureRO: public MemRegionClosure {
duke@435	94	public:
duke@435	95	void* operator new(size_t size, ResourceObj::allocation_type type) {
duke@435	96	return ResourceObj::operator new(size, type);
duke@435	97	}
duke@435	98	void* operator new(size_t size, Arena *arena) {
duke@435	99	return ResourceObj::operator new(size, arena);
duke@435	100	}
duke@435	101	void* operator new(size_t size) {
duke@435	102	return ResourceObj::operator new(size);
duke@435	103	}
duke@435	104
duke@435	105	void operator delete(void* p) {} // nothing to do
duke@435	106	};