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src/share/vm/prims/jniFastGetField.hpp@c18cbe5936b8 (annotated)

src/share/vm/prims/jniFastGetField.hpp

Thu, 27 May 2010 19:08:38 -0700

author

trims

date

Thu, 27 May 2010 19:08:38 -0700

changeset 1907

c18cbe5936b8

parent 435

a61af66fc99e

child 2314

f95d63e2154a

permissions

-rw-r--r--

6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair

duke@435	1	/*
trims@1907	2	* Copyright (c) 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	// Basic logic of a fast version of jni_Get<Primitive>Field:
duke@435	26	//
duke@435	27	// (See safepoint.hpp for a description of _safepoint_counter)
duke@435	28	//
duke@435	29	// load _safepoint_counter into old_counter
duke@435	30	// IF old_counter is odd THEN
duke@435	31	// a safepoint is going on, return jni_GetXXXField
duke@435	32	// ELSE
duke@435	33	// load the primitive field value into result (speculatively)
duke@435	34	// load _safepoint_counter into new_counter
duke@435	35	// IF (old_counter == new_counter) THEN
duke@435	36	// no safepoint happened during the field access, return result
duke@435	37	// ELSE
duke@435	38	// a safepoint might have happened in-between, return jni_GetXXXField()
duke@435	39	// ENDIF
duke@435	40	// ENDIF
duke@435	41	//
duke@435	42	// LoadLoad membars to maintain the load order may be necessary
duke@435	43	// for some platforms.
duke@435	44	//
duke@435	45	// The fast versions don't check for pending suspension request.
duke@435	46	// This is fine since it's totally read-only and doesn't create new race.
duke@435	47	//
duke@435	48	// There is a hypothetical safepoint counter wraparound. But it's not
duke@435	49	// a practical concern.
duke@435	50
duke@435	51	class JNI_FastGetField : AllStatic {
duke@435	52	private:
duke@435	53	enum { LIST_CAPACITY = 40 }; // a conservative number for the number of
duke@435	54	// speculative loads on all the platforms
duke@435	55	static address speculative_load_pclist [];
duke@435	56	static address slowcase_entry_pclist [];
duke@435	57	static int count;
duke@435	58
duke@435	59	static address generate_fast_get_int_field0(BasicType type);
duke@435	60	static address generate_fast_get_float_field0(BasicType type);
duke@435	61
duke@435	62	public:
duke@435	63	#if defined(_WINDOWS) && !defined(_WIN64)
duke@435	64	static GetBooleanField_t jni_fast_GetBooleanField_fp;
duke@435	65	static GetByteField_t jni_fast_GetByteField_fp;
duke@435	66	static GetCharField_t jni_fast_GetCharField_fp;
duke@435	67	static GetShortField_t jni_fast_GetShortField_fp;
duke@435	68	static GetIntField_t jni_fast_GetIntField_fp;
duke@435	69	static GetLongField_t jni_fast_GetLongField_fp;
duke@435	70	static GetFloatField_t jni_fast_GetFloatField_fp;
duke@435	71	static GetDoubleField_t jni_fast_GetDoubleField_fp;
duke@435	72	#endif
duke@435	73
duke@435	74	static address generate_fast_get_boolean_field();
duke@435	75	static address generate_fast_get_byte_field();
duke@435	76	static address generate_fast_get_char_field();
duke@435	77	static address generate_fast_get_short_field();
duke@435	78	static address generate_fast_get_int_field();
duke@435	79	static address generate_fast_get_long_field();
duke@435	80	static address generate_fast_get_float_field();
duke@435	81	static address generate_fast_get_double_field();
duke@435	82
duke@435	83	// If pc is in speculative_load_pclist, return the corresponding
duke@435	84	// slow case entry pc. Otherwise, return -1.
duke@435	85	// This is used by signal/exception handler to handle such case:
duke@435	86	// After an even safepoint counter is loaded and a fast field access
duke@435	87	// is about to begin, a GC kicks in and shrinks the heap. Then the
duke@435	88	// field access may fault. The signal/exception handler needs to
duke@435	89	// return to the slow case.
duke@435	90	//
duke@435	91	// The GC may decide to temporarily stuff some bad values into handles,
duke@435	92	// for example, for debugging purpose, in which case we need the mapping also.
duke@435	93	static address find_slowcase_pc(address pc);
duke@435	94	};