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src/share/vm/code/oopRecorder.hpp@b1f619d38249 (annotated)

src/share/vm/code/oopRecorder.hpp

Tue, 05 Jan 2010 16:12:26 -0800

author

never

date

Tue, 05 Jan 2010 16:12:26 -0800

changeset 1576

b1f619d38249

parent 435

a61af66fc99e

child 1907

c18cbe5936b8

child 1918

1a5913bf5e19

permissions

-rw-r--r--

6914002: unsigned compare problem after 5057818
Reviewed-by: kvn, twisti

duke@435	1	/*
duke@435	2	* Copyright 1998-2005 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	// Recording and retrieval of oop relocations in compiled code.
duke@435	26
duke@435	27	class CodeBlob;
duke@435	28
duke@435	29	class OopRecorder : public ResourceObj {
duke@435	30	public:
duke@435	31	// A two-way mapping from positive indexes to oop handles.
duke@435	32	// The zero index is reserved for a constant (sharable) null.
duke@435	33	// Indexes may not be negative.
duke@435	34
duke@435	35	// Use the given arena to manage storage, if not NULL.
duke@435	36	// By default, uses the current ResourceArea.
duke@435	37	OopRecorder(Arena* arena = NULL);
duke@435	38
duke@435	39	// Generate a new index on which CodeBlob::oop_addr_at will work.
duke@435	40	// allocate_index and find_index never return the same index,
duke@435	41	// and allocate_index never returns the same index twice.
duke@435	42	// In fact, two successive calls to allocate_index return successive ints.
duke@435	43	int allocate_index(jobject h) {
duke@435	44	return add_handle(h, false);
duke@435	45	}
duke@435	46
duke@435	47	// For a given jobject, this will return the same index repeatedly.
duke@435	48	// The index can later be given to oop_at to retrieve the oop.
duke@435	49	// However, the oop must not be changed via CodeBlob::oop_addr_at.
duke@435	50	int find_index(jobject h) {
duke@435	51	int index = maybe_find_index(h);
duke@435	52	if (index < 0) { // previously unallocated
duke@435	53	index = add_handle(h, true);
duke@435	54	}
duke@435	55	return index;
duke@435	56	}
duke@435	57
duke@435	58	// variant of find_index which does not allocate if not found (yields -1)
duke@435	59	int maybe_find_index(jobject h);
duke@435	60
duke@435	61	// returns the size of the generated oop table, for sizing the CodeBlob.
duke@435	62	// must be called after all oops are allocated!
duke@435	63	int oop_size();
duke@435	64
duke@435	65	// Retrieve the oop handle at a given index.
duke@435	66	jobject handle_at(int index);
duke@435	67
duke@435	68	int element_count() {
duke@435	69	// there is always a NULL virtually present as first object
duke@435	70	return _handles->length() + first_index;
duke@435	71	}
duke@435	72
duke@435	73	// copy the generated oop table to CodeBlob
duke@435	74	void copy_to(CodeBlob* code); // => code->copy_oops(_handles)
duke@435	75
duke@435	76	bool is_unused() { return _handles == NULL && !_complete; }
duke@435	77	#ifdef ASSERT
duke@435	78	bool is_complete() { return _complete; }
duke@435	79	#endif
duke@435	80
duke@435	81	private:
duke@435	82	// leaky hash table of handle => index, to help detect duplicate insertion
duke@435	83	class IndexCache: public ResourceObj {
duke@435	84	// This class is only used by the OopRecorder class.
duke@435	85	friend class OopRecorder;
duke@435	86	enum {
duke@435	87	_log_cache_size = 9,
duke@435	88	_cache_size = (1<<_log_cache_size),
duke@435	89	// Index entries are ints. The LSBit is a collision indicator.
duke@435	90	_collision_bit_shift = 0,
duke@435	91	_collision_bit = 1,
duke@435	92	_index_shift = _collision_bit_shift+1
duke@435	93	};
duke@435	94	int _cache[_cache_size];
duke@435	95	static juint cache_index(jobject handle) {
duke@435	96	juint ci = (int) (intptr_t) handle;
duke@435	97	ci ^= ci >> (BitsPerByte*2);
duke@435	98	ci += ci >> (BitsPerByte*1);
duke@435	99	return ci & (_cache_size-1);
duke@435	100	}
duke@435	101	int* cache_location(jobject handle) {
duke@435	102	return &_cache[ cache_index(handle) ];
duke@435	103	}
duke@435	104	static bool cache_location_collision(int* cloc) {
duke@435	105	return ((*cloc) & _collision_bit) != 0;
duke@435	106	}
duke@435	107	static int cache_location_index(int* cloc) {
duke@435	108	return (*cloc) >> _index_shift;
duke@435	109	}
duke@435	110	static void set_cache_location_index(int* cloc, int index) {
duke@435	111	int cval0 = (*cloc);
duke@435	112	int cval1 = (index << _index_shift);
duke@435	113	if (cval0 != 0 && cval1 != cval0) cval1 += _collision_bit;
duke@435	114	(*cloc) = cval1;
duke@435	115	}
duke@435	116	IndexCache();
duke@435	117	};
duke@435	118
duke@435	119	// Helper function; returns false for NULL or Universe::non_oop_word().
duke@435	120	inline bool is_real_jobject(jobject h);
duke@435	121
duke@435	122	void maybe_initialize();
duke@435	123	int add_handle(jobject h, bool make_findable);
duke@435	124
duke@435	125	enum { null_index = 0, first_index = 1, index_cache_threshold = 20 };
duke@435	126
duke@435	127	GrowableArray<jobject>* _handles; // ordered list (first is always NULL)
duke@435	128	GrowableArray<int>* _no_finds; // all unfindable indexes; usually empty
duke@435	129	IndexCache* _indexes; // map: jobject -> its probable index
duke@435	130	Arena* _arena;
duke@435	131	bool _complete;
duke@435	132
duke@435	133	#ifdef ASSERT
duke@435	134	static int _find_index_calls, _hit_indexes, _missed_indexes;
duke@435	135	#endif
duke@435	136	};