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src/share/vm/oops/fieldInfo.hpp@71afdabfd05b (annotated)

src/share/vm/oops/fieldInfo.hpp

Mon, 21 May 2012 14:10:35 -0400

author

jiangli

date

Mon, 21 May 2012 14:10:35 -0400

changeset 3803

71afdabfd05b

parent 3137

e6b1331a51d2

child 4037

da91efe96a93

permissions

-rw-r--r--

7168280: Eliminate the generic signature index slot from field array for field without generic signature.
Summary: Only allocate the generic signature index slot in the field array for field with generic signature attribute.
Reviewed-by: coleenp, dlong

never@3137	1	/*
never@3137	2	* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
never@3137	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
never@3137	4	*
never@3137	5	* This code is free software; you can redistribute it and/or modify it
never@3137	6	* under the terms of the GNU General Public License version 2 only, as
never@3137	7	* published by the Free Software Foundation.
never@3137	8	*
never@3137	9	* This code is distributed in the hope that it will be useful, but WITHOUT
never@3137	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
never@3137	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
never@3137	12	* version 2 for more details (a copy is included in the LICENSE file that
never@3137	13	* accompanied this code).
never@3137	14	*
never@3137	15	* You should have received a copy of the GNU General Public License version
never@3137	16	* 2 along with this work; if not, write to the Free Software Foundation,
never@3137	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
never@3137	18	*
never@3137	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
never@3137	20	* or visit www.oracle.com if you need additional information or have any
never@3137	21	* questions.
never@3137	22	*
never@3137	23	*/
never@3137	24
never@3137	25	#ifndef SHARE_VM_OOPS_FIELDINFO_HPP
never@3137	26	#define SHARE_VM_OOPS_FIELDINFO_HPP
never@3137	27
never@3137	28	#include "oops/typeArrayOop.hpp"
never@3137	29	#include "classfile/vmSymbols.hpp"
never@3137	30
never@3137	31	// This class represents the field information contained in the fields
never@3137	32	// array of an instanceKlass. Currently it's laid on top an array of
never@3137	33	// Java shorts but in the future it could simply be used as a real
never@3137	34	// array type. FieldInfo generally shouldn't be used directly.
never@3137	35	// Fields should be queried either through instanceKlass or through
never@3137	36	// the various FieldStreams.
never@3137	37	class FieldInfo VALUE_OBJ_CLASS_SPEC {
never@3137	38	friend class fieldDescriptor;
never@3137	39	friend class JavaFieldStream;
never@3137	40	friend class ClassFileParser;
never@3137	41
never@3137	42	public:
never@3137	43	// fields
never@3137	44	// Field info extracted from the class file and stored
never@3137	45	// as an array of 7 shorts
never@3137	46	enum FieldOffset {
never@3137	47	access_flags_offset = 0,
never@3137	48	name_index_offset = 1,
never@3137	49	signature_index_offset = 2,
never@3137	50	initval_index_offset = 3,
never@3137	51	low_offset = 4,
never@3137	52	high_offset = 5,
jiangli@3803	53	field_slots = 6
never@3137	54	};
never@3137	55
never@3137	56	private:
never@3137	57	u2 _shorts[field_slots];
never@3137	58
never@3137	59	void set_name_index(u2 val) { _shorts[name_index_offset] = val; }
never@3137	60	void set_signature_index(u2 val) { _shorts[signature_index_offset] = val; }
never@3137	61	void set_initval_index(u2 val) { _shorts[initval_index_offset] = val; }
never@3137	62
never@3137	63	u2 name_index() const { return _shorts[name_index_offset]; }
never@3137	64	u2 signature_index() const { return _shorts[signature_index_offset]; }
never@3137	65	u2 initval_index() const { return _shorts[initval_index_offset]; }
never@3137	66
never@3137	67	public:
never@3137	68	static FieldInfo* from_field_array(typeArrayOop fields, int index) {
never@3137	69	return ((FieldInfo*)fields->short_at_addr(index * field_slots));
never@3137	70	}
jiangli@3803	71	static FieldInfo* from_field_array(u2* fields, int index) {
jiangli@3803	72	return ((FieldInfo*)(fields + index * field_slots));
jiangli@3803	73	}
never@3137	74
never@3137	75	void initialize(u2 access_flags,
never@3137	76	u2 name_index,
never@3137	77	u2 signature_index,
never@3137	78	u2 initval_index,
never@3137	79	u4 offset) {
never@3137	80	_shorts[access_flags_offset] = access_flags;
never@3137	81	_shorts[name_index_offset] = name_index;
never@3137	82	_shorts[signature_index_offset] = signature_index;
never@3137	83	_shorts[initval_index_offset] = initval_index;
never@3137	84	set_offset(offset);
never@3137	85	}
never@3137	86
never@3137	87	u2 access_flags() const { return _shorts[access_flags_offset]; }
never@3137	88	u4 offset() const { return build_int_from_shorts(_shorts[low_offset], _shorts[high_offset]); }
never@3137	89
never@3137	90	Symbol* name(constantPoolHandle cp) const {
never@3137	91	int index = name_index();
never@3137	92	if (is_internal()) {
never@3137	93	return lookup_symbol(index);
never@3137	94	}
never@3137	95	return cp->symbol_at(index);
never@3137	96	}
never@3137	97
never@3137	98	Symbol* signature(constantPoolHandle cp) const {
never@3137	99	int index = signature_index();
never@3137	100	if (is_internal()) {
never@3137	101	return lookup_symbol(index);
never@3137	102	}
never@3137	103	return cp->symbol_at(index);
never@3137	104	}
never@3137	105
never@3137	106	void set_access_flags(u2 val) { _shorts[access_flags_offset] = val; }
never@3137	107	void set_offset(u4 val) {
never@3137	108	_shorts[low_offset] = extract_low_short_from_int(val);
never@3137	109	_shorts[high_offset] = extract_high_short_from_int(val);
never@3137	110	}
never@3137	111
never@3137	112	bool is_internal() const {
never@3137	113	return (access_flags() & JVM_ACC_FIELD_INTERNAL) != 0;
never@3137	114	}
never@3137	115
never@3137	116	Symbol* lookup_symbol(int symbol_index) const {
never@3137	117	assert(is_internal(), "only internal fields");
never@3137	118	return vmSymbols::symbol_at((vmSymbols::SID)symbol_index);
never@3137	119	}
never@3137	120	};
never@3137	121
never@3137	122	#endif // SHARE_VM_OOPS_FIELDINFO_HPP