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src/share/vm/memory/memRegion.cpp@710a3c8b516e (annotated)

src/share/vm/memory/memRegion.cpp

Tue, 08 Aug 2017 15:57:29 +0800

author

aoqi

date

Tue, 08 Aug 2017 15:57:29 +0800

changeset 6876

710a3c8b516e

parent 5614

9758d9f36299

parent 0

f90c822e73f8

child 7535

7ae4e26cb1e0

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	#include "precompiled.hpp"
aoqi@0	26	#include "memory/allocation.hpp"
aoqi@0	27	#include "memory/allocation.inline.hpp"
aoqi@0	28	#include "memory/memRegion.hpp"
aoqi@0	29	#include "runtime/globals.hpp"
aoqi@0	30
aoqi@0	31	// A very simple data structure representing a contigous word-aligned
aoqi@0	32	// region of address space.
aoqi@0	33
aoqi@0	34	MemRegion MemRegion::intersection(const MemRegion mr2) const {
aoqi@0	35	MemRegion res;
aoqi@0	36	HeapWord* res_start = MAX2(start(), mr2.start());
aoqi@0	37	HeapWord* res_end = MIN2(end(), mr2.end());
aoqi@0	38	if (res_start < res_end) {
aoqi@0	39	res.set_start(res_start);
aoqi@0	40	res.set_end(res_end);
aoqi@0	41	}
aoqi@0	42	return res;
aoqi@0	43	}
aoqi@0	44
aoqi@0	45	MemRegion MemRegion::_union(const MemRegion mr2) const {
aoqi@0	46	// If one region is empty, return the other
aoqi@0	47	if (is_empty()) return mr2;
aoqi@0	48	if (mr2.is_empty()) return MemRegion(start(), end());
aoqi@0	49
aoqi@0	50	// Otherwise, regions must overlap or be adjacent
aoqi@0	51	assert(((start() <= mr2.start()) && (end() >= mr2.start())) ||
aoqi@0	52	((mr2.start() <= start()) && (mr2.end() >= start())),
aoqi@0	53	"non-adjacent or overlapping regions");
aoqi@0	54	MemRegion res;
aoqi@0	55	HeapWord* res_start = MIN2(start(), mr2.start());
aoqi@0	56	HeapWord* res_end = MAX2(end(), mr2.end());
aoqi@0	57	res.set_start(res_start);
aoqi@0	58	res.set_end(res_end);
aoqi@0	59	return res;
aoqi@0	60	}
aoqi@0	61
aoqi@0	62	MemRegion MemRegion::minus(const MemRegion mr2) const {
aoqi@0	63	// There seem to be 6 cases:
aoqi@0	64	// |this MemRegion|
aoqi@0	65	// |strictly below|
aoqi@0	66	// |overlap beginning|
aoqi@0	67	// |interior|
aoqi@0	68	// |overlap ending|
aoqi@0	69	// |strictly above|
aoqi@0	70	// |completely overlapping|
aoqi@0	71	// We can't deal with an interior case because it would
aoqi@0	72	// produce two disjoint regions as a result.
aoqi@0	73	// We aren't trying to be optimal in the number of tests below,
aoqi@0	74	// but the order is important to distinguish the strictly cases
aoqi@0	75	// from the overlapping cases.
aoqi@0	76	if (mr2.end() <= start()) {
aoqi@0	77	// strictly below
aoqi@0	78	return MemRegion(start(), end());
aoqi@0	79	}
aoqi@0	80	if (mr2.start() <= start() && mr2.end() <= end()) {
aoqi@0	81	// overlap beginning
aoqi@0	82	return MemRegion(mr2.end(), end());
aoqi@0	83	}
aoqi@0	84	if (mr2.start() >= end()) {
aoqi@0	85	// strictly above
aoqi@0	86	return MemRegion(start(), end());
aoqi@0	87	}
aoqi@0	88	if (mr2.start() >= start() && mr2.end() >= end()) {
aoqi@0	89	// overlap ending
aoqi@0	90	return MemRegion(start(), mr2.start());
aoqi@0	91	}
aoqi@0	92	if (mr2.start() <= start() && mr2.end() >= end()) {
aoqi@0	93	// completely overlapping
aoqi@0	94	return MemRegion();
aoqi@0	95	}
aoqi@0	96	if (mr2.start() > start() && mr2.end() < end()) {
aoqi@0	97	// interior
aoqi@0	98	guarantee(false, "MemRegion::minus, but interior");
aoqi@0	99	return MemRegion();
aoqi@0	100	}
aoqi@0	101	ShouldNotReachHere();
aoqi@0	102	return MemRegion();
aoqi@0	103	}
aoqi@0	104
aoqi@0	105	void* MemRegion::operator new(size_t size) throw() {
aoqi@0	106	return (address)AllocateHeap(size, mtGC, 0, AllocFailStrategy::RETURN_NULL);
aoqi@0	107	}
aoqi@0	108
aoqi@0	109	void* MemRegion::operator new [](size_t size) throw() {
aoqi@0	110	return (address)AllocateHeap(size, mtGC, 0, AllocFailStrategy::RETURN_NULL);
aoqi@0	111	}
aoqi@0	112	void MemRegion::operator delete(void* p) {
aoqi@0	113	FreeHeap(p, mtGC);
aoqi@0	114	}
aoqi@0	115
aoqi@0	116	void MemRegion::operator delete [](void* p) {
aoqi@0	117	FreeHeap(p, mtGC);
aoqi@0	118	}
aoqi@0	119