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src/share/vm/oops/objArrayOop.hpp@6aa7255741f3 (annotated)

src/share/vm/oops/objArrayOop.hpp

Thu, 03 Dec 2009 15:01:57 -0800

author

ysr

date

Thu, 03 Dec 2009 15:01:57 -0800

changeset 1526

6aa7255741f3

parent 1383

89e0543e1737

child 1530

7bfd295ec074

permissions

-rw-r--r--

6906727: UseCompressedOops: some card-marking fixes related to object arrays
Summary: Introduced a new write_ref_array(HeapWords* start, size_t count) method that does the requisite MemRegion range calculation so (some of the) clients of the erstwhile write_ref_array(MemRegion mr) do not need to worry. This removed all external uses of array_size(), which was also simplified and made private. Asserts were added to catch other possible issues. Further, less essential, fixes stemming from this investigation are deferred to CR 6904516 (to follow shortly in hs17).
Reviewed-by: kvn, coleenp, jmasa

duke@435	1	/*
xdono@1383	2	* Copyright 1997-2009 Sun Microsystems, Inc. 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	*
duke@435	19	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435	20	* CA 95054 USA or visit www.sun.com if you need additional information or
duke@435	21	* have any questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// An objArrayOop is an array containing oops.
duke@435	26	// Evaluating "String arg[10]" will create an objArrayOop.
duke@435	27
duke@435	28	class objArrayOopDesc : public arrayOopDesc {
coleenp@548	29	friend class objArrayKlass;
coleenp@548	30	friend class Runtime1;
coleenp@548	31	friend class psPromotionManager;
ysr@777	32	friend class CSMarkOopClosure;
ysr@777	33	friend class G1ParScanPartialArrayClosure;
coleenp@548	34
coleenp@548	35	template <class T> T* obj_at_addr(int index) const {
coleenp@548	36	assert(is_within_bounds(index), "index out of bounds");
coleenp@548	37	return &((T*)base())[index];
coleenp@548	38	}
coleenp@548	39
ysr@1526	40	private:
ysr@1526	41	// Give size of objArrayOop in HeapWords minus the header
ysr@1526	42	static int array_size(int length) {
ysr@1526	43	const int OopsPerHeapWord = HeapWordSize/heapOopSize;
ysr@1526	44	assert(OopsPerHeapWord >= 1 && (HeapWordSize % heapOopSize == 0),
ysr@1526	45	"Else the following (new) computation would be in error");
ysr@1526	46	#ifdef ASSERT
ysr@1526	47	// The old code is left in for sanity-checking; it'll
ysr@1526	48	// go away pretty soon. XXX
ysr@1526	49	// Without UseCompressedOops, this is simply:
ysr@1526	50	// oop->length() * HeapWordsPerOop;
ysr@1526	51	// With narrowOops, HeapWordsPerOop is 1/2 or equal 0 as an integer.
ysr@1526	52	// The oop elements are aligned up to wordSize
ysr@1526	53	const int HeapWordsPerOop = heapOopSize/HeapWordSize;
ysr@1526	54	int old_res;
ysr@1526	55	if (HeapWordsPerOop > 0) {
ysr@1526	56	old_res = length * HeapWordsPerOop;
ysr@1526	57	} else {
ysr@1526	58	old_res = align_size_up(length, OopsPerHeapWord)/OopsPerHeapWord;
ysr@1526	59	}
ysr@1526	60	#endif // ASSERT
ysr@1526	61	int res = (length + OopsPerHeapWord - 1)/OopsPerHeapWord;
ysr@1526	62	assert(res == old_res, "Inconsistency between old and new.");
ysr@1526	63	return res;
ysr@1526	64	}
ysr@1526	65
duke@435	66	public:
twisti@1330	67	// Returns the offset of the first element.
twisti@1330	68	static int base_offset_in_bytes() {
twisti@1330	69	return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
twisti@1330	70	}
twisti@1330	71
coleenp@548	72	// base is the address following the header.
coleenp@548	73	HeapWord* base() const { return (HeapWord*) arrayOopDesc::base(T_OBJECT); }
coleenp@548	74
duke@435	75	// Accessing
coleenp@548	76	oop obj_at(int index) const {
coleenp@548	77	// With UseCompressedOops decode the narrow oop in the objArray to an
coleenp@548	78	// uncompressed oop. Otherwise this is simply a "*" operator.
coleenp@548	79	if (UseCompressedOops) {
coleenp@548	80	return load_decode_heap_oop(obj_at_addr<narrowOop>(index));
coleenp@548	81	} else {
coleenp@548	82	return load_decode_heap_oop(obj_at_addr<oop>(index));
coleenp@548	83	}
coleenp@548	84	}
duke@435	85
coleenp@548	86	void obj_at_put(int index, oop value) {
coleenp@548	87	if (UseCompressedOops) {
coleenp@548	88	oop_store(obj_at_addr<narrowOop>(index), value);
coleenp@548	89	} else {
coleenp@548	90	oop_store(obj_at_addr<oop>(index), value);
coleenp@548	91	}
coleenp@548	92	}
duke@435	93	// Sizing
coleenp@548	94	static int header_size() { return arrayOopDesc::header_size(T_OBJECT); }
coleenp@548	95	int object_size() { return object_size(length()); }
duke@435	96
coleenp@548	97	static int object_size(int length) {
coleenp@548	98	// This returns the object size in HeapWords.
coleenp@548	99	return align_object_size(header_size() + array_size(length));
duke@435	100	}
coleenp@548	101
coleenp@548	102	// special iterators for index ranges, returns size of object
coleenp@548	103	#define ObjArrayOop_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \
coleenp@548	104	int oop_iterate_range(OopClosureType* blk, int start, int end);
coleenp@548	105
coleenp@548	106	ALL_OOP_OOP_ITERATE_CLOSURES_1(ObjArrayOop_OOP_ITERATE_DECL)
ysr@777	107	ALL_OOP_OOP_ITERATE_CLOSURES_2(ObjArrayOop_OOP_ITERATE_DECL)
duke@435	108	};