1 /*
2 * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.misc;
27
28 import jdk.internal.HotSpotIntrinsicCandidate;
29 import jdk.internal.vm.annotation.ForceInline;
30
31 import java.lang.reflect.Field;
32 import java.security.ProtectionDomain;
33
34
35 /**
36 * A collection of methods for performing low-level, unsafe operations.
37 * Although the class and all methods are public, use of this class is
38 * limited because only trusted code can obtain instances of it.
39 *
40 * <em>Note:</em> It is the resposibility of the caller to make sure
41 * arguments are checked before methods of this class are
42 * called. While some rudimentary checks are performed on the input,
43 * the checks are best effort and when performance is an overriding
44 * priority, as when methods of this class are optimized by the
45 * runtime compiler, some or all checks (if any) may be elided. Hence,
46 * the caller must not rely on the checks and corresponding
47 * exceptions!
48 *
49 * @author John R. Rose
50 * @see #getUnsafe
51 */
52
53 public final class Unsafe {
54
55 private static native void registerNatives();
56 static {
57 registerNatives();
58 }
59
60 private Unsafe() {}
61
62 private static final Unsafe theUnsafe = new Unsafe();
63
64 /**
65 * Provides the caller with the capability of performing unsafe
66 * operations.
67 *
68 * <p>The returned {@code Unsafe} object should be carefully guarded
69 * by the caller, since it can be used to read and write data at arbitrary
70 * memory addresses. It must never be passed to untrusted code.
71 *
72 * <p>Most methods in this class are very low-level, and correspond to a
73 * small number of hardware instructions (on typical machines). Compilers
74 * are encouraged to optimize these methods accordingly.
75 *
76 * <p>Here is a suggested idiom for using unsafe operations:
77 *
78 * <pre> {@code
79 * class MyTrustedClass {
80 * private static final Unsafe unsafe = Unsafe.getUnsafe();
81 * ...
82 * private long myCountAddress = ...;
83 * public int getCount() { return unsafe.getByte(myCountAddress); }
84 * }}</pre>
85 *
86 * (It may assist compilers to make the local variable {@code final}.)
87 */
88 public static Unsafe getUnsafe() {
89 return theUnsafe;
90 }
91
92 /// peek and poke operations
93 /// (compilers should optimize these to memory ops)
94
95 // These work on object fields in the Java heap.
96 // They will not work on elements of packed arrays.
97
98 /**
99 * Fetches a value from a given Java variable.
100 * More specifically, fetches a field or array element within the given
101 * object {@code o} at the given offset, or (if {@code o} is null)
102 * from the memory address whose numerical value is the given offset.
103 * <p>
104 * The results are undefined unless one of the following cases is true:
105 * <ul>
106 * <li>The offset was obtained from {@link #objectFieldOffset} on
107 * the {@link java.lang.reflect.Field} of some Java field and the object
108 * referred to by {@code o} is of a class compatible with that
109 * field's class.
110 *
111 * <li>The offset and object reference {@code o} (either null or
112 * non-null) were both obtained via {@link #staticFieldOffset}
113 * and {@link #staticFieldBase} (respectively) from the
114 * reflective {@link Field} representation of some Java field.
115 *
116 * <li>The object referred to by {@code o} is an array, and the offset
117 * is an integer of the form {@code B+N*S}, where {@code N} is
118 * a valid index into the array, and {@code B} and {@code S} are
119 * the values obtained by {@link #arrayBaseOffset} and {@link
120 * #arrayIndexScale} (respectively) from the array's class. The value
121 * referred to is the {@code N}<em>th</em> element of the array.
122 *
123 * </ul>
124 * <p>
125 * If one of the above cases is true, the call references a specific Java
126 * variable (field or array element). However, the results are undefined
127 * if that variable is not in fact of the type returned by this method.
128 * <p>
129 * This method refers to a variable by means of two parameters, and so
130 * it provides (in effect) a <em>double-register</em> addressing mode
131 * for Java variables. When the object reference is null, this method
132 * uses its offset as an absolute address. This is similar in operation
133 * to methods such as {@link #getInt(long)}, which provide (in effect) a
134 * <em>single-register</em> addressing mode for non-Java variables.
135 * However, because Java variables may have a different layout in memory
136 * from non-Java variables, programmers should not assume that these
137 * two addressing modes are ever equivalent. Also, programmers should
138 * remember that offsets from the double-register addressing mode cannot
139 * be portably confused with longs used in the single-register addressing
140 * mode.
141 *
142 * @param o Java heap object in which the variable resides, if any, else
143 * null
144 * @param offset indication of where the variable resides in a Java heap
145 * object, if any, else a memory address locating the variable
146 * statically
147 * @return the value fetched from the indicated Java variable
148 * @throws RuntimeException No defined exceptions are thrown, not even
149 * {@link NullPointerException}
150 */
151 @HotSpotIntrinsicCandidate
152 public native int getInt(Object o, long offset);
153
154 /**
155 * Stores a value into a given Java variable.
156 * <p>
157 * The first two parameters are interpreted exactly as with
158 * {@link #getInt(Object, long)} to refer to a specific
159 * Java variable (field or array element). The given value
160 * is stored into that variable.
161 * <p>
162 * The variable must be of the same type as the method
163 * parameter {@code x}.
164 *
165 * @param o Java heap object in which the variable resides, if any, else
166 * null
167 * @param offset indication of where the variable resides in a Java heap
168 * object, if any, else a memory address locating the variable
169 * statically
170 * @param x the value to store into the indicated Java variable
171 * @throws RuntimeException No defined exceptions are thrown, not even
172 * {@link NullPointerException}
173 */
174 @HotSpotIntrinsicCandidate
175 public native void putInt(Object o, long offset, int x);
176
177 /**
178 * Returns true if the given class is a regular value type.
179 */
180 public boolean isValueType(Class<?> c) {
181 return c.isValue() && c == c.asValueType();
182 }
183
184 private static final int JVM_ACC_FLATTENED = 0x00008000; // HotSpot-specific bit
185
186 /**
187 * Returns true if the given field is flattened.
188 */
189 public boolean isFlattened(Field f) {
190 return (f.getModifiers() & JVM_ACC_FLATTENED) == JVM_ACC_FLATTENED;
191 }
192
193 /**
194 * Returns true if the given class is a flattened array.
195 */
196 public native boolean isFlattenedArray(Class<?> arrayClass);
197
198 /**
199 * Fetches a reference value from a given Java variable.
200 * This method can return a reference to either an object or value
201 * or a null reference.
202 *
203 * @see #getInt(Object, long)
204 */
205 @HotSpotIntrinsicCandidate
206 public native Object getObject(Object o, long offset);
207
208 /**
209 * Stores a reference value into a given Java variable.
210 * This method can store a reference to either an object or value
211 * or a null reference.
212 * <p>
213 * Unless the reference {@code x} being stored is either null
214 * or matches the field type, the results are undefined.
215 * If the reference {@code o} is non-null, card marks or
216 * other store barriers for that object (if the VM requires them)
217 * are updated.
218 * @see #putInt(Object, long, int)
219 */
220 @HotSpotIntrinsicCandidate
221 public native void putObject(Object o, long offset, Object x);
222
223 /**
224 * Fetches a value of type {@code <V>} from a given Java variable.
225 * More specifically, fetches a field or array element within the given
226 * {@code o} object at the given offset, or (if {@code o} is null)
227 * from the memory address whose numerical value is the given offset.
228 *
229 * @param o Java heap object in which the variable resides, if any, else
230 * null
231 * @param offset indication of where the variable resides in a Java heap
232 * object, if any, else a memory address locating the variable
233 * statically
234 * @param vc value class
235 * @param <V> the type of a value
236 * @return the value fetched from the indicated Java variable
237 * @throws RuntimeException No defined exceptions are thrown, not even
238 * {@link NullPointerException}
239 */
240 public native <V> V getValue(Object o, long offset, Class<?> vc);
241
242 /**
243 * Stores the given value into a given Java variable.
244 *
245 * Unless the reference {@code o} being stored is either null
246 * or matches the field type and not in a value container,
247 * the results are undefined.
248 *
249 * @param o Java heap object in which the variable resides, if any, else
250 * null
251 * @param offset indication of where the variable resides in a Java heap
252 * object, if any, else a memory address locating the variable
253 * statically
254 * @param vc value class
255 * @param v the value to store into the indicated Java variable
256 * @param <V> the type of a value
257 * @throws RuntimeException No defined exceptions are thrown, not even
258 * {@link NullPointerException}
259 */
260 public native <V> void putValue(Object o, long offset, Class<?> vc, V v);
261
262 /**
263 * Starts a private buffer
264 */
265 public native <V> V startPrivateBuffer(V value);
266
267 public native <V> V finishPrivateBuffer(V value);
268
269 /**
270 * Updates an int field of a value instance of type {@code V}
271 * addressed by the given {@code o} object at the given offset
272 * with {@code x} and returns the new value.
273 *
274 * Unless the reference {@code o} being stored is either null
275 * or matches the field type, the results are undefined.
276 *
277 * @param vc Value class V
278 * @param o Java heap object in which the variable resides, if any, else
279 * null
280 * @param offset indication of where the variable resides in a Java heap
281 * object, if any, else a memory address locating the variable
282 * statically
283 * @param x the value to store into the indicated Java variable
284 * @param <V> Value class
285 * @return an instance of the given value class
286 */
287 public native <V> V withInt(Class<V> vc, Object o, long offset, int x);
288
289 /** @see #withInt(Class, Object, long, int) */
290 public native <V> V withBoolean(Class<V> vc, Object o, long offset, boolean x);
291
292 /** @see #withInt(Class, Object, long, int) */
293 public native <V> V withByte(Class<V> vc, Object o, long offset, byte x);
294
295 /** @see #withInt(Class, Object, long, int) */
296 public native <V> V withShort(Class<V> vc, Object o, long offset, short x);
297
298 /** @see #withInt(Class, Object, long, int) */
299 public native <V> V withChar(Class<V> vc, Object o, long offset, char x);
300
301 /** @see #withInt(Class, Object, long, int) */
302 public native <V> V withLong(Class<V> vc, Object o, long offset, long x);
303
304 /** @see #withInt(Class, Object, long, int) */
305 public native <V> V withFloat(Class<V> vc, Object o, long offset, float x);
306
307 /** @see #withInt(Class, Object, long, int) */
308 public native <V> V withDouble(Class<V> vc, Object o, long offset, double x);
309
310 /** @see #withInt(Class, Object, long, int) */
311 public native <V> V withReference(Class<V> vc, Object o, long offset, Object x);
312
313 /**
314 * Updates a field of a value instance of type {@code V} addressed by
315 * the given {@code o} object at the given offset with {@code x}
316 * and returns the new value.
317 *
318 * Unless the reference {@code o} being stored is either null
319 * or matches the field type, the results are undefined.
320 *
321 * @param vc Value class V
322 * @param o Java heap object in which the variable resides, if any, else null
323 * @param vc_offset indication of where the variable resides in a Java heap
324 * object, if any, else a memory address locating the variable
325 * statically
326 * @param xc_offset offset from the field addressed by o and vc_offset
327 * @param xc The type of the field to be updated
328 * @param x the value to store into the indicated Java variable
329 * @param <V> the containing class
330 * @param <X> the field type
331 * @return an instance of the given containing class
332 */
333 public native <V,X> V withValue(Class<V> vc, Object o, long vc_offset, long xc_offset, Class<X> xc, X x);
334
335 /**
336 * Returns the header size of the given value class
337 *
338 * @param vc Value class
339 * @param <V> value clas
340 * @return the header size of the value class
341 */
342 public native <V> long valueHeaderSize(Class<V> vc);
343
344 /** @see #getInt(Object, long) */
345 @HotSpotIntrinsicCandidate
346 public native boolean getBoolean(Object o, long offset);
347
348 /** @see #putInt(Object, long, int) */
349 @HotSpotIntrinsicCandidate
350 public native void putBoolean(Object o, long offset, boolean x);
351
352 /** @see #getInt(Object, long) */
353 @HotSpotIntrinsicCandidate
354 public native byte getByte(Object o, long offset);
355
356 /** @see #putInt(Object, long, int) */
357 @HotSpotIntrinsicCandidate
358 public native void putByte(Object o, long offset, byte x);
359
360 /** @see #getInt(Object, long) */
361 @HotSpotIntrinsicCandidate
362 public native short getShort(Object o, long offset);
363
364 /** @see #putInt(Object, long, int) */
365 @HotSpotIntrinsicCandidate
366 public native void putShort(Object o, long offset, short x);
367
368 /** @see #getInt(Object, long) */
369 @HotSpotIntrinsicCandidate
370 public native char getChar(Object o, long offset);
371
372 /** @see #putInt(Object, long, int) */
373 @HotSpotIntrinsicCandidate
374 public native void putChar(Object o, long offset, char x);
375
376 /** @see #getInt(Object, long) */
377 @HotSpotIntrinsicCandidate
378 public native long getLong(Object o, long offset);
379
380 /** @see #putInt(Object, long, int) */
381 @HotSpotIntrinsicCandidate
382 public native void putLong(Object o, long offset, long x);
383
384 /** @see #getInt(Object, long) */
385 @HotSpotIntrinsicCandidate
386 public native float getFloat(Object o, long offset);
387
388 /** @see #putInt(Object, long, int) */
389 @HotSpotIntrinsicCandidate
390 public native void putFloat(Object o, long offset, float x);
391
392 /** @see #getInt(Object, long) */
393 @HotSpotIntrinsicCandidate
394 public native double getDouble(Object o, long offset);
395
396 /** @see #putInt(Object, long, int) */
397 @HotSpotIntrinsicCandidate
398 public native void putDouble(Object o, long offset, double x);
399
400 /**
401 * Fetches a native pointer from a given memory address. If the address is
402 * zero, or does not point into a block obtained from {@link
403 * #allocateMemory}, the results are undefined.
404 *
405 * <p>If the native pointer is less than 64 bits wide, it is extended as
406 * an unsigned number to a Java long. The pointer may be indexed by any
407 * given byte offset, simply by adding that offset (as a simple integer) to
408 * the long representing the pointer. The number of bytes actually read
409 * from the target address may be determined by consulting {@link
410 * #addressSize}.
411 *
412 * @see #allocateMemory
413 * @see #getInt(Object, long)
414 */
415 @ForceInline
416 public long getAddress(Object o, long offset) {
417 if (ADDRESS_SIZE == 4) {
418 return Integer.toUnsignedLong(getInt(o, offset));
419 } else {
420 return getLong(o, offset);
421 }
422 }
423
424 /**
425 * Stores a native pointer into a given memory address. If the address is
426 * zero, or does not point into a block obtained from {@link
427 * #allocateMemory}, the results are undefined.
428 *
429 * <p>The number of bytes actually written at the target address may be
430 * determined by consulting {@link #addressSize}.
431 *
432 * @see #allocateMemory
433 * @see #putInt(Object, long, int)
434 */
435 @ForceInline
436 public void putAddress(Object o, long offset, long x) {
437 if (ADDRESS_SIZE == 4) {
438 putInt(o, offset, (int)x);
439 } else {
440 putLong(o, offset, x);
441 }
442 }
443
444 // These read VM internal data.
445
446 /**
447 * Fetches an uncompressed reference value from a given native variable
448 * ignoring the VM's compressed references mode.
449 *
450 * @param address a memory address locating the variable
451 * @return the value fetched from the indicated native variable
452 */
453 public native Object getUncompressedObject(long address);
454
455 // These work on values in the C heap.
456
457 /**
458 * Fetches a value from a given memory address. If the address is zero, or
459 * does not point into a block obtained from {@link #allocateMemory}, the
460 * results are undefined.
461 *
462 * @see #allocateMemory
463 */
464 @ForceInline
465 public byte getByte(long address) {
466 return getByte(null, address);
467 }
468
469 /**
470 * Stores a value into a given memory address. If the address is zero, or
471 * does not point into a block obtained from {@link #allocateMemory}, the
472 * results are undefined.
473 *
474 * @see #getByte(long)
475 */
476 @ForceInline
477 public void putByte(long address, byte x) {
478 putByte(null, address, x);
479 }
480
481 /** @see #getByte(long) */
482 @ForceInline
483 public short getShort(long address) {
484 return getShort(null, address);
485 }
486
487 /** @see #putByte(long, byte) */
488 @ForceInline
489 public void putShort(long address, short x) {
490 putShort(null, address, x);
491 }
492
493 /** @see #getByte(long) */
494 @ForceInline
495 public char getChar(long address) {
496 return getChar(null, address);
497 }
498
499 /** @see #putByte(long, byte) */
500 @ForceInline
501 public void putChar(long address, char x) {
502 putChar(null, address, x);
503 }
504
505 /** @see #getByte(long) */
506 @ForceInline
507 public int getInt(long address) {
508 return getInt(null, address);
509 }
510
511 /** @see #putByte(long, byte) */
512 @ForceInline
513 public void putInt(long address, int x) {
514 putInt(null, address, x);
515 }
516
517 /** @see #getByte(long) */
518 @ForceInline
519 public long getLong(long address) {
520 return getLong(null, address);
521 }
522
523 /** @see #putByte(long, byte) */
524 @ForceInline
525 public void putLong(long address, long x) {
526 putLong(null, address, x);
527 }
528
529 /** @see #getByte(long) */
530 @ForceInline
531 public float getFloat(long address) {
532 return getFloat(null, address);
533 }
534
535 /** @see #putByte(long, byte) */
536 @ForceInline
537 public void putFloat(long address, float x) {
538 putFloat(null, address, x);
539 }
540
541 /** @see #getByte(long) */
542 @ForceInline
543 public double getDouble(long address) {
544 return getDouble(null, address);
545 }
546
547 /** @see #putByte(long, byte) */
548 @ForceInline
549 public void putDouble(long address, double x) {
550 putDouble(null, address, x);
551 }
552
553 /** @see #getAddress(Object, long) */
554 @ForceInline
555 public long getAddress(long address) {
556 return getAddress(null, address);
557 }
558
559 /** @see #putAddress(Object, long, long) */
560 @ForceInline
561 public void putAddress(long address, long x) {
562 putAddress(null, address, x);
563 }
564
565
566
567 /// helper methods for validating various types of objects/values
568
569 /**
570 * Create an exception reflecting that some of the input was invalid
571 *
572 * <em>Note:</em> It is the resposibility of the caller to make
573 * sure arguments are checked before the methods are called. While
574 * some rudimentary checks are performed on the input, the checks
575 * are best effort and when performance is an overriding priority,
576 * as when methods of this class are optimized by the runtime
577 * compiler, some or all checks (if any) may be elided. Hence, the
578 * caller must not rely on the checks and corresponding
579 * exceptions!
580 *
581 * @return an exception object
582 */
583 private RuntimeException invalidInput() {
584 return new IllegalArgumentException();
585 }
586
587 /**
588 * Check if a value is 32-bit clean (32 MSB are all zero)
589 *
590 * @param value the 64-bit value to check
591 *
592 * @return true if the value is 32-bit clean
593 */
594 private boolean is32BitClean(long value) {
595 return value >>> 32 == 0;
596 }
597
598 /**
599 * Check the validity of a size (the equivalent of a size_t)
600 *
601 * @throws RuntimeException if the size is invalid
602 * (<em>Note:</em> after optimization, invalid inputs may
603 * go undetected, which will lead to unpredictable
604 * behavior)
605 */
606 private void checkSize(long size) {
607 if (ADDRESS_SIZE == 4) {
608 // Note: this will also check for negative sizes
609 if (!is32BitClean(size)) {
610 throw invalidInput();
611 }
612 } else if (size < 0) {
613 throw invalidInput();
614 }
615 }
616
617 /**
618 * Check the validity of a native address (the equivalent of void*)
619 *
620 * @throws RuntimeException if the address is invalid
621 * (<em>Note:</em> after optimization, invalid inputs may
622 * go undetected, which will lead to unpredictable
623 * behavior)
624 */
625 private void checkNativeAddress(long address) {
626 if (ADDRESS_SIZE == 4) {
627 // Accept both zero and sign extended pointers. A valid
628 // pointer will, after the +1 below, either have produced
629 // the value 0x0 or 0x1. Masking off the low bit allows
630 // for testing against 0.
631 if ((((address >> 32) + 1) & ~1) != 0) {
632 throw invalidInput();
633 }
634 }
635 }
636
637 /**
638 * Check the validity of an offset, relative to a base object
639 *
640 * @param o the base object
641 * @param offset the offset to check
642 *
643 * @throws RuntimeException if the size is invalid
644 * (<em>Note:</em> after optimization, invalid inputs may
645 * go undetected, which will lead to unpredictable
646 * behavior)
647 */
648 private void checkOffset(Object o, long offset) {
649 if (ADDRESS_SIZE == 4) {
650 // Note: this will also check for negative offsets
651 if (!is32BitClean(offset)) {
652 throw invalidInput();
653 }
654 } else if (offset < 0) {
655 throw invalidInput();
656 }
657 }
658
659 /**
660 * Check the validity of a double-register pointer
661 *
662 * Note: This code deliberately does *not* check for NPE for (at
663 * least) three reasons:
664 *
665 * 1) NPE is not just NULL/0 - there is a range of values all
666 * resulting in an NPE, which is not trivial to check for
667 *
668 * 2) It is the responsibility of the callers of Unsafe methods
669 * to verify the input, so throwing an exception here is not really
670 * useful - passing in a NULL pointer is a critical error and the
671 * must not expect an exception to be thrown anyway.
672 *
673 * 3) the actual operations will detect NULL pointers anyway by
674 * means of traps and signals (like SIGSEGV).
675 *
676 * @param o Java heap object, or null
677 * @param offset indication of where the variable resides in a Java heap
678 * object, if any, else a memory address locating the variable
679 * statically
680 *
681 * @throws RuntimeException if the pointer is invalid
682 * (<em>Note:</em> after optimization, invalid inputs may
683 * go undetected, which will lead to unpredictable
684 * behavior)
685 */
686 private void checkPointer(Object o, long offset) {
687 if (o == null) {
688 checkNativeAddress(offset);
689 } else {
690 checkOffset(o, offset);
691 }
692 }
693
694 /**
695 * Check if a type is a primitive array type
696 *
697 * @param c the type to check
698 *
699 * @return true if the type is a primitive array type
700 */
701 private void checkPrimitiveArray(Class<?> c) {
702 Class<?> componentType = c.getComponentType();
703 if (componentType == null || !componentType.isPrimitive()) {
704 throw invalidInput();
705 }
706 }
707
708 /**
709 * Check that a pointer is a valid primitive array type pointer
710 *
711 * Note: pointers off-heap are considered to be primitive arrays
712 *
713 * @throws RuntimeException if the pointer is invalid
714 * (<em>Note:</em> after optimization, invalid inputs may
715 * go undetected, which will lead to unpredictable
716 * behavior)
717 */
718 private void checkPrimitivePointer(Object o, long offset) {
719 checkPointer(o, offset);
720
721 if (o != null) {
722 // If on heap, it must be a primitive array
723 checkPrimitiveArray(o.getClass());
724 }
725 }
726
727
728 /// wrappers for malloc, realloc, free:
729
730 /**
731 * Allocates a new block of native memory, of the given size in bytes. The
732 * contents of the memory are uninitialized; they will generally be
733 * garbage. The resulting native pointer will never be zero, and will be
734 * aligned for all value types. Dispose of this memory by calling {@link
735 * #freeMemory}, or resize it with {@link #reallocateMemory}.
736 *
737 * <em>Note:</em> It is the resposibility of the caller to make
738 * sure arguments are checked before the methods are called. While
739 * some rudimentary checks are performed on the input, the checks
740 * are best effort and when performance is an overriding priority,
741 * as when methods of this class are optimized by the runtime
742 * compiler, some or all checks (if any) may be elided. Hence, the
743 * caller must not rely on the checks and corresponding
744 * exceptions!
745 *
746 * @throws RuntimeException if the size is negative or too large
747 * for the native size_t type
748 *
749 * @throws OutOfMemoryError if the allocation is refused by the system
750 *
751 * @see #getByte(long)
752 * @see #putByte(long, byte)
753 */
754 public long allocateMemory(long bytes) {
755 allocateMemoryChecks(bytes);
756
757 if (bytes == 0) {
758 return 0;
759 }
760
761 long p = allocateMemory0(bytes);
762 if (p == 0) {
763 throw new OutOfMemoryError();
764 }
765
766 return p;
767 }
768
769 /**
770 * Validate the arguments to allocateMemory
771 *
772 * @throws RuntimeException if the arguments are invalid
773 * (<em>Note:</em> after optimization, invalid inputs may
774 * go undetected, which will lead to unpredictable
775 * behavior)
776 */
777 private void allocateMemoryChecks(long bytes) {
778 checkSize(bytes);
779 }
780
781 /**
782 * Resizes a new block of native memory, to the given size in bytes. The
783 * contents of the new block past the size of the old block are
784 * uninitialized; they will generally be garbage. The resulting native
785 * pointer will be zero if and only if the requested size is zero. The
786 * resulting native pointer will be aligned for all value types. Dispose
787 * of this memory by calling {@link #freeMemory}, or resize it with {@link
788 * #reallocateMemory}. The address passed to this method may be null, in
789 * which case an allocation will be performed.
790 *
791 * <em>Note:</em> It is the resposibility of the caller to make
792 * sure arguments are checked before the methods are called. While
793 * some rudimentary checks are performed on the input, the checks
794 * are best effort and when performance is an overriding priority,
795 * as when methods of this class are optimized by the runtime
796 * compiler, some or all checks (if any) may be elided. Hence, the
797 * caller must not rely on the checks and corresponding
798 * exceptions!
799 *
800 * @throws RuntimeException if the size is negative or too large
801 * for the native size_t type
802 *
803 * @throws OutOfMemoryError if the allocation is refused by the system
804 *
805 * @see #allocateMemory
806 */
807 public long reallocateMemory(long address, long bytes) {
808 reallocateMemoryChecks(address, bytes);
809
810 if (bytes == 0) {
811 freeMemory(address);
812 return 0;
813 }
814
815 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
816 if (p == 0) {
817 throw new OutOfMemoryError();
818 }
819
820 return p;
821 }
822
823 /**
824 * Validate the arguments to reallocateMemory
825 *
826 * @throws RuntimeException if the arguments are invalid
827 * (<em>Note:</em> after optimization, invalid inputs may
828 * go undetected, which will lead to unpredictable
829 * behavior)
830 */
831 private void reallocateMemoryChecks(long address, long bytes) {
832 checkPointer(null, address);
833 checkSize(bytes);
834 }
835
836 /**
837 * Sets all bytes in a given block of memory to a fixed value
838 * (usually zero).
839 *
840 * <p>This method determines a block's base address by means of two parameters,
841 * and so it provides (in effect) a <em>double-register</em> addressing mode,
842 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
843 * the offset supplies an absolute base address.
844 *
845 * <p>The stores are in coherent (atomic) units of a size determined
846 * by the address and length parameters. If the effective address and
847 * length are all even modulo 8, the stores take place in 'long' units.
848 * If the effective address and length are (resp.) even modulo 4 or 2,
849 * the stores take place in units of 'int' or 'short'.
850 *
851 * <em>Note:</em> It is the resposibility of the caller to make
852 * sure arguments are checked before the methods are called. While
853 * some rudimentary checks are performed on the input, the checks
854 * are best effort and when performance is an overriding priority,
855 * as when methods of this class are optimized by the runtime
856 * compiler, some or all checks (if any) may be elided. Hence, the
857 * caller must not rely on the checks and corresponding
858 * exceptions!
859 *
860 * @throws RuntimeException if any of the arguments is invalid
861 *
862 * @since 1.7
863 */
864 public void setMemory(Object o, long offset, long bytes, byte value) {
865 setMemoryChecks(o, offset, bytes, value);
866
867 if (bytes == 0) {
868 return;
869 }
870
871 setMemory0(o, offset, bytes, value);
872 }
873
874 /**
875 * Sets all bytes in a given block of memory to a fixed value
876 * (usually zero). This provides a <em>single-register</em> addressing mode,
877 * as discussed in {@link #getInt(Object,long)}.
878 *
879 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
880 */
881 public void setMemory(long address, long bytes, byte value) {
882 setMemory(null, address, bytes, value);
883 }
884
885 /**
886 * Validate the arguments to setMemory
887 *
888 * @throws RuntimeException if the arguments are invalid
889 * (<em>Note:</em> after optimization, invalid inputs may
890 * go undetected, which will lead to unpredictable
891 * behavior)
892 */
893 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
894 checkPrimitivePointer(o, offset);
895 checkSize(bytes);
896 }
897
898 /**
899 * Sets all bytes in a given block of memory to a copy of another
900 * block.
901 *
902 * <p>This method determines each block's base address by means of two parameters,
903 * and so it provides (in effect) a <em>double-register</em> addressing mode,
904 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
905 * the offset supplies an absolute base address.
906 *
907 * <p>The transfers are in coherent (atomic) units of a size determined
908 * by the address and length parameters. If the effective addresses and
909 * length are all even modulo 8, the transfer takes place in 'long' units.
910 * If the effective addresses and length are (resp.) even modulo 4 or 2,
911 * the transfer takes place in units of 'int' or 'short'.
912 *
913 * <em>Note:</em> It is the resposibility of the caller to make
914 * sure arguments are checked before the methods are called. While
915 * some rudimentary checks are performed on the input, the checks
916 * are best effort and when performance is an overriding priority,
917 * as when methods of this class are optimized by the runtime
918 * compiler, some or all checks (if any) may be elided. Hence, the
919 * caller must not rely on the checks and corresponding
920 * exceptions!
921 *
922 * @throws RuntimeException if any of the arguments is invalid
923 *
924 * @since 1.7
925 */
926 public void copyMemory(Object srcBase, long srcOffset,
927 Object destBase, long destOffset,
928 long bytes) {
929 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
930
931 if (bytes == 0) {
932 return;
933 }
934
935 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
936 }
937
938 /**
939 * Sets all bytes in a given block of memory to a copy of another
940 * block. This provides a <em>single-register</em> addressing mode,
941 * as discussed in {@link #getInt(Object,long)}.
942 *
943 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
944 */
945 public void copyMemory(long srcAddress, long destAddress, long bytes) {
946 copyMemory(null, srcAddress, null, destAddress, bytes);
947 }
948
949 /**
950 * Validate the arguments to copyMemory
951 *
952 * @throws RuntimeException if any of the arguments is invalid
953 * (<em>Note:</em> after optimization, invalid inputs may
954 * go undetected, which will lead to unpredictable
955 * behavior)
956 */
957 private void copyMemoryChecks(Object srcBase, long srcOffset,
958 Object destBase, long destOffset,
959 long bytes) {
960 checkSize(bytes);
961 checkPrimitivePointer(srcBase, srcOffset);
962 checkPrimitivePointer(destBase, destOffset);
963 }
964
965 /**
966 * Copies all elements from one block of memory to another block,
967 * *unconditionally* byte swapping the elements on the fly.
968 *
969 * <p>This method determines each block's base address by means of two parameters,
970 * and so it provides (in effect) a <em>double-register</em> addressing mode,
971 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
972 * the offset supplies an absolute base address.
973 *
974 * <em>Note:</em> It is the resposibility of the caller to make
975 * sure arguments are checked before the methods are called. While
976 * some rudimentary checks are performed on the input, the checks
977 * are best effort and when performance is an overriding priority,
978 * as when methods of this class are optimized by the runtime
979 * compiler, some or all checks (if any) may be elided. Hence, the
980 * caller must not rely on the checks and corresponding
981 * exceptions!
982 *
983 * @throws RuntimeException if any of the arguments is invalid
984 *
985 * @since 9
986 */
987 public void copySwapMemory(Object srcBase, long srcOffset,
988 Object destBase, long destOffset,
989 long bytes, long elemSize) {
990 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
991
992 if (bytes == 0) {
993 return;
994 }
995
996 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
997 }
998
999 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
1000 Object destBase, long destOffset,
1001 long bytes, long elemSize) {
1002 checkSize(bytes);
1003
1004 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
1005 throw invalidInput();
1006 }
1007 if (bytes % elemSize != 0) {
1008 throw invalidInput();
1009 }
1010
1011 checkPrimitivePointer(srcBase, srcOffset);
1012 checkPrimitivePointer(destBase, destOffset);
1013 }
1014
1015 /**
1016 * Copies all elements from one block of memory to another block, byte swapping the
1017 * elements on the fly.
1018 *
1019 * This provides a <em>single-register</em> addressing mode, as
1020 * discussed in {@link #getInt(Object,long)}.
1021 *
1022 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
1023 */
1024 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
1025 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
1026 }
1027
1028 /**
1029 * Disposes of a block of native memory, as obtained from {@link
1030 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
1031 * this method may be null, in which case no action is taken.
1032 *
1033 * <em>Note:</em> It is the resposibility of the caller to make
1034 * sure arguments are checked before the methods are called. While
1035 * some rudimentary checks are performed on the input, the checks
1036 * are best effort and when performance is an overriding priority,
1037 * as when methods of this class are optimized by the runtime
1038 * compiler, some or all checks (if any) may be elided. Hence, the
1039 * caller must not rely on the checks and corresponding
1040 * exceptions!
1041 *
1042 * @throws RuntimeException if any of the arguments is invalid
1043 *
1044 * @see #allocateMemory
1045 */
1046 public void freeMemory(long address) {
1047 freeMemoryChecks(address);
1048
1049 if (address == 0) {
1050 return;
1051 }
1052
1053 freeMemory0(address);
1054 }
1055
1056 /**
1057 * Validate the arguments to freeMemory
1058 *
1059 * @throws RuntimeException if the arguments are invalid
1060 * (<em>Note:</em> after optimization, invalid inputs may
1061 * go undetected, which will lead to unpredictable
1062 * behavior)
1063 */
1064 private void freeMemoryChecks(long address) {
1065 checkPointer(null, address);
1066 }
1067
1068 /// random queries
1069
1070 /**
1071 * This constant differs from all results that will ever be returned from
1072 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1073 * or {@link #arrayBaseOffset}.
1074 */
1075 public static final int INVALID_FIELD_OFFSET = -1;
1076
1077 /**
1078 * Reports the location of a given field in the storage allocation of its
1079 * class. Do not expect to perform any sort of arithmetic on this offset;
1080 * it is just a cookie which is passed to the unsafe heap memory accessors.
1081 *
1082 * <p>Any given field will always have the same offset and base, and no
1083 * two distinct fields of the same class will ever have the same offset
1084 * and base.
1085 *
1086 * <p>As of 1.4.1, offsets for fields are represented as long values,
1087 * although the Sun JVM does not use the most significant 32 bits.
1088 * However, JVM implementations which store static fields at absolute
1089 * addresses can use long offsets and null base pointers to express
1090 * the field locations in a form usable by {@link #getInt(Object,long)}.
1091 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1092 * must preserve all bits of static field offsets.
1093 * @see #getInt(Object, long)
1094 */
1095 public long objectFieldOffset(Field f) {
1096 if (f == null) {
1097 throw new NullPointerException();
1098 }
1099
1100 return objectFieldOffset0(f);
1101 }
1102
1103 /**
1104 * Reports the location of the field with a given name in the storage
1105 * allocation of its class.
1106 *
1107 * @throws NullPointerException if any parameter is {@code null}.
1108 * @throws InternalError if there is no field named {@code name} declared
1109 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1110 * would throw {@code java.lang.NoSuchFieldException}.
1111 *
1112 * @see #objectFieldOffset(Field)
1113 */
1114 public long objectFieldOffset(Class<?> c, String name) {
1115 if (c == null || name == null) {
1116 throw new NullPointerException();
1117 }
1118
1119 return objectFieldOffset1(c, name);
1120 }
1121
1122 /**
1123 * Reports the location of a given static field, in conjunction with {@link
1124 * #staticFieldBase}.
1125 * <p>Do not expect to perform any sort of arithmetic on this offset;
1126 * it is just a cookie which is passed to the unsafe heap memory accessors.
1127 *
1128 * <p>Any given field will always have the same offset, and no two distinct
1129 * fields of the same class will ever have the same offset.
1130 *
1131 * <p>As of 1.4.1, offsets for fields are represented as long values,
1132 * although the Sun JVM does not use the most significant 32 bits.
1133 * It is hard to imagine a JVM technology which needs more than
1134 * a few bits to encode an offset within a non-array object,
1135 * However, for consistency with other methods in this class,
1136 * this method reports its result as a long value.
1137 * @see #getInt(Object, long)
1138 */
1139 public long staticFieldOffset(Field f) {
1140 if (f == null) {
1141 throw new NullPointerException();
1142 }
1143
1144 return staticFieldOffset0(f);
1145 }
1146
1147 /**
1148 * Reports the location of a given static field, in conjunction with {@link
1149 * #staticFieldOffset}.
1150 * <p>Fetch the base "Object", if any, with which static fields of the
1151 * given class can be accessed via methods like {@link #getInt(Object,
1152 * long)}. This value may be null. This value may refer to an object
1153 * which is a "cookie", not guaranteed to be a real Object, and it should
1154 * not be used in any way except as argument to the get and put routines in
1155 * this class.
1156 */
1157 public Object staticFieldBase(Field f) {
1158 if (f == null) {
1159 throw new NullPointerException();
1160 }
1161
1162 return staticFieldBase0(f);
1163 }
1164
1165 /**
1166 * Detects if the given class may need to be initialized. This is often
1167 * needed in conjunction with obtaining the static field base of a
1168 * class.
1169 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1170 */
1171 public boolean shouldBeInitialized(Class<?> c) {
1172 if (c == null) {
1173 throw new NullPointerException();
1174 }
1175
1176 return shouldBeInitialized0(c);
1177 }
1178
1179 /**
1180 * Ensures the given class has been initialized. This is often
1181 * needed in conjunction with obtaining the static field base of a
1182 * class.
1183 */
1184 public void ensureClassInitialized(Class<?> c) {
1185 if (c == null) {
1186 throw new NullPointerException();
1187 }
1188
1189 ensureClassInitialized0(c);
1190 }
1191
1192 /**
1193 * Reports the offset of the first element in the storage allocation of a
1194 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1195 * for the same class, you may use that scale factor, together with this
1196 * base offset, to form new offsets to access elements of arrays of the
1197 * given class.
1198 *
1199 * @see #getInt(Object, long)
1200 * @see #putInt(Object, long, int)
1201 */
1202 public int arrayBaseOffset(Class<?> arrayClass) {
1203 if (arrayClass == null) {
1204 throw new NullPointerException();
1205 }
1206
1207 return arrayBaseOffset0(arrayClass);
1208 }
1209
1210
1211 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1212 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1213 = theUnsafe.arrayBaseOffset(boolean[].class);
1214
1215 /** The value of {@code arrayBaseOffset(byte[].class)} */
1216 public static final int ARRAY_BYTE_BASE_OFFSET
1217 = theUnsafe.arrayBaseOffset(byte[].class);
1218
1219 /** The value of {@code arrayBaseOffset(short[].class)} */
1220 public static final int ARRAY_SHORT_BASE_OFFSET
1221 = theUnsafe.arrayBaseOffset(short[].class);
1222
1223 /** The value of {@code arrayBaseOffset(char[].class)} */
1224 public static final int ARRAY_CHAR_BASE_OFFSET
1225 = theUnsafe.arrayBaseOffset(char[].class);
1226
1227 /** The value of {@code arrayBaseOffset(int[].class)} */
1228 public static final int ARRAY_INT_BASE_OFFSET
1229 = theUnsafe.arrayBaseOffset(int[].class);
1230
1231 /** The value of {@code arrayBaseOffset(long[].class)} */
1232 public static final int ARRAY_LONG_BASE_OFFSET
1233 = theUnsafe.arrayBaseOffset(long[].class);
1234
1235 /** The value of {@code arrayBaseOffset(float[].class)} */
1236 public static final int ARRAY_FLOAT_BASE_OFFSET
1237 = theUnsafe.arrayBaseOffset(float[].class);
1238
1239 /** The value of {@code arrayBaseOffset(double[].class)} */
1240 public static final int ARRAY_DOUBLE_BASE_OFFSET
1241 = theUnsafe.arrayBaseOffset(double[].class);
1242
1243 /** The value of {@code arrayBaseOffset(Object[].class)} */
1244 public static final int ARRAY_OBJECT_BASE_OFFSET
1245 = theUnsafe.arrayBaseOffset(Object[].class);
1246
1247 /**
1248 * Reports the scale factor for addressing elements in the storage
1249 * allocation of a given array class. However, arrays of "narrow" types
1250 * will generally not work properly with accessors like {@link
1251 * #getByte(Object, long)}, so the scale factor for such classes is reported
1252 * as zero.
1253 *
1254 * @see #arrayBaseOffset
1255 * @see #getInt(Object, long)
1256 * @see #putInt(Object, long, int)
1257 */
1258 public int arrayIndexScale(Class<?> arrayClass) {
1259 if (arrayClass == null) {
1260 throw new NullPointerException();
1261 }
1262
1263 return arrayIndexScale0(arrayClass);
1264 }
1265
1266
1267 /** The value of {@code arrayIndexScale(boolean[].class)} */
1268 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1269 = theUnsafe.arrayIndexScale(boolean[].class);
1270
1271 /** The value of {@code arrayIndexScale(byte[].class)} */
1272 public static final int ARRAY_BYTE_INDEX_SCALE
1273 = theUnsafe.arrayIndexScale(byte[].class);
1274
1275 /** The value of {@code arrayIndexScale(short[].class)} */
1276 public static final int ARRAY_SHORT_INDEX_SCALE
1277 = theUnsafe.arrayIndexScale(short[].class);
1278
1279 /** The value of {@code arrayIndexScale(char[].class)} */
1280 public static final int ARRAY_CHAR_INDEX_SCALE
1281 = theUnsafe.arrayIndexScale(char[].class);
1282
1283 /** The value of {@code arrayIndexScale(int[].class)} */
1284 public static final int ARRAY_INT_INDEX_SCALE
1285 = theUnsafe.arrayIndexScale(int[].class);
1286
1287 /** The value of {@code arrayIndexScale(long[].class)} */
1288 public static final int ARRAY_LONG_INDEX_SCALE
1289 = theUnsafe.arrayIndexScale(long[].class);
1290
1291 /** The value of {@code arrayIndexScale(float[].class)} */
1292 public static final int ARRAY_FLOAT_INDEX_SCALE
1293 = theUnsafe.arrayIndexScale(float[].class);
1294
1295 /** The value of {@code arrayIndexScale(double[].class)} */
1296 public static final int ARRAY_DOUBLE_INDEX_SCALE
1297 = theUnsafe.arrayIndexScale(double[].class);
1298
1299 /** The value of {@code arrayIndexScale(Object[].class)} */
1300 public static final int ARRAY_OBJECT_INDEX_SCALE
1301 = theUnsafe.arrayIndexScale(Object[].class);
1302
1303 /**
1304 * Reports the size in bytes of a native pointer, as stored via {@link
1305 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1306 * other primitive types (as stored in native memory blocks) is determined
1307 * fully by their information content.
1308 */
1309 public int addressSize() {
1310 return ADDRESS_SIZE;
1311 }
1312
1313 /** The value of {@code addressSize()} */
1314 public static final int ADDRESS_SIZE = theUnsafe.addressSize0();
1315
1316 /**
1317 * Reports the size in bytes of a native memory page (whatever that is).
1318 * This value will always be a power of two.
1319 */
1320 public native int pageSize();
1321
1322
1323 /// random trusted operations from JNI:
1324
1325 /**
1326 * Tells the VM to define a class, without security checks. By default, the
1327 * class loader and protection domain come from the caller's class.
1328 */
1329 public Class<?> defineClass(String name, byte[] b, int off, int len,
1330 ClassLoader loader,
1331 ProtectionDomain protectionDomain) {
1332 if (b == null) {
1333 throw new NullPointerException();
1334 }
1335 if (len < 0) {
1336 throw new ArrayIndexOutOfBoundsException();
1337 }
1338
1339 return defineClass0(name, b, off, len, loader, protectionDomain);
1340 }
1341
1342 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1343 ClassLoader loader,
1344 ProtectionDomain protectionDomain);
1345
1346 /**
1347 * Defines a class but does not make it known to the class loader or system dictionary.
1348 * <p>
1349 * For each CP entry, the corresponding CP patch must either be null or have
1350 * the a format that matches its tag:
1351 * <ul>
1352 * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
1353 * <li>Utf8: a string (must have suitable syntax if used as signature or name)
1354 * <li>Class: any java.lang.Class object
1355 * <li>String: any object (not just a java.lang.String)
1356 * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
1357 * </ul>
1358 * @param hostClass context for linkage, access control, protection domain, and class loader
1359 * @param data bytes of a class file
1360 * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
1361 */
1362 public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {
1363 if (hostClass == null || data == null) {
1364 throw new NullPointerException();
1365 }
1366 if (hostClass.isArray() || hostClass.isPrimitive()) {
1367 throw new IllegalArgumentException();
1368 }
1369
1370 return defineAnonymousClass0(hostClass, data, cpPatches);
1371 }
1372
1373 /**
1374 * Allocates an instance but does not run any constructor.
1375 * Initializes the class if it has not yet been.
1376 */
1377 @HotSpotIntrinsicCandidate
1378 public native Object allocateInstance(Class<?> cls)
1379 throws InstantiationException;
1380
1381 /**
1382 * Allocates an array of a given type, but does not do zeroing.
1383 * <p>
1384 * This method should only be used in the very rare cases where a high-performance code
1385 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1386 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1387 * <p>
1388 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1389 * before allowing untrusted code, or code in other threads, to observe the reference
1390 * to the newly allocated array. In addition, the publication of the array reference must be
1391 * safe according to the Java Memory Model requirements.
1392 * <p>
1393 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1394 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1395 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1396 * or issuing a {@link #storeFence} before publishing the reference.
1397 * <p>
1398 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1399 * elements that could break heap integrity.
1400 *
1401 * @param componentType array component type to allocate
1402 * @param length array size to allocate
1403 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1404 * or the length is negative
1405 */
1406 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1407 if (componentType == null) {
1408 throw new IllegalArgumentException("Component type is null");
1409 }
1410 if (!componentType.isPrimitive()) {
1411 throw new IllegalArgumentException("Component type is not primitive");
1412 }
1413 if (length < 0) {
1414 throw new IllegalArgumentException("Negative length");
1415 }
1416 return allocateUninitializedArray0(componentType, length);
1417 }
1418
1419 @HotSpotIntrinsicCandidate
1420 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1421 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1422 // return the zeroed arrays.
1423 if (componentType == byte.class) return new byte[length];
1424 if (componentType == boolean.class) return new boolean[length];
1425 if (componentType == short.class) return new short[length];
1426 if (componentType == char.class) return new char[length];
1427 if (componentType == int.class) return new int[length];
1428 if (componentType == float.class) return new float[length];
1429 if (componentType == long.class) return new long[length];
1430 if (componentType == double.class) return new double[length];
1431 return null;
1432 }
1433
1434 /** Throws the exception without telling the verifier. */
1435 public native void throwException(Throwable ee);
1436
1437 /**
1438 * Atomically updates Java variable to {@code x} if it is currently
1439 * holding {@code expected}.
1440 *
1441 * <p>This operation has memory semantics of a {@code volatile} read
1442 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1443 *
1444 * @return {@code true} if successful
1445 */
1446 @HotSpotIntrinsicCandidate
1447 public final native boolean compareAndSetObject(Object o, long offset,
1448 Object expected,
1449 Object x);
1450
1451 @ForceInline
1452 public final <V> boolean compareAndSetValue(Object o, long offset,
1453 Class<?> valueType,
1454 V expected,
1455 V x) {
1456 synchronized (valueLock) {
1457 Object witness = getValue(o, offset, valueType);
1458 if (witness.equals(expected)) {
1459 putValue(o, offset, valueType, x);
1460 return true;
1461 }
1462 else {
1463 return false;
1464 }
1465 }
1466 }
1467
1468 @HotSpotIntrinsicCandidate
1469 public final native Object compareAndExchangeObject(Object o, long offset,
1470 Object expected,
1471 Object x);
1472 @ForceInline
1473 public final <V> Object compareAndExchangeValue(Object o, long offset,
1474 Class<?> valueType,
1475 V expected,
1476 V x) {
1477 synchronized (valueLock) {
1478 Object witness = getValue(o, offset, valueType);
1479 if (witness.equals(expected)) {
1480 putValue(o, offset, valueType, x);
1481 }
1482 return witness;
1483 }
1484 }
1485
1486 @HotSpotIntrinsicCandidate
1487 public final Object compareAndExchangeObjectAcquire(Object o, long offset,
1488 Object expected,
1489 Object x) {
1490 return compareAndExchangeObject(o, offset, expected, x);
1491 }
1492
1493 @ForceInline
1494 public final <V> Object compareAndExchangeValueAcquire(Object o, long offset,
1495 Class<?> valueType,
1496 V expected,
1497 V x) {
1498 return compareAndExchangeValue(o, offset, valueType, expected, x);
1499 }
1500
1501 @HotSpotIntrinsicCandidate
1502 public final Object compareAndExchangeObjectRelease(Object o, long offset,
1503 Object expected,
1504 Object x) {
1505 return compareAndExchangeObject(o, offset, expected, x);
1506 }
1507
1508 @ForceInline
1509 public final <V> Object compareAndExchangeValueRelease(Object o, long offset,
1510 Class<?> valueType,
1511 V expected,
1512 V x) {
1513 return compareAndExchangeValue(o, offset, valueType, expected, x);
1514 }
1515
1516 @HotSpotIntrinsicCandidate
1517 public final boolean weakCompareAndSetObjectPlain(Object o, long offset,
1518 Object expected,
1519 Object x) {
1520 return compareAndSetObject(o, offset, expected, x);
1521 }
1522
1523 @ForceInline
1524 public final <V> boolean weakCompareAndSetValuePlain(Object o, long offset,
1525 Class<?> valueType,
1526 V expected,
1527 V x) {
1528 return compareAndSetValue(o, offset, valueType, expected, x);
1529 }
1530
1531 @HotSpotIntrinsicCandidate
1532 public final boolean weakCompareAndSetObjectAcquire(Object o, long offset,
1533 Object expected,
1534 Object x) {
1535 return compareAndSetObject(o, offset, expected, x);
1536 }
1537
1538 @ForceInline
1539 public final <V> boolean weakCompareAndSetValueAcquire(Object o, long offset,
1540 Class<?> valueType,
1541 V expected,
1542 V x) {
1543 return compareAndSetValue(o, offset, valueType, expected, x);
1544 }
1545
1546 @HotSpotIntrinsicCandidate
1547 public final boolean weakCompareAndSetObjectRelease(Object o, long offset,
1548 Object expected,
1549 Object x) {
1550 return compareAndSetObject(o, offset, expected, x);
1551 }
1552
1553 @ForceInline
1554 public final <V> boolean weakCompareAndSetValueRelease(Object o, long offset,
1555 Class<?> valueType,
1556 V expected,
1557 V x) {
1558 return compareAndSetValue(o, offset, valueType, expected, x);
1559 }
1560
1561 @HotSpotIntrinsicCandidate
1562 public final boolean weakCompareAndSetObject(Object o, long offset,
1563 Object expected,
1564 Object x) {
1565 return compareAndSetObject(o, offset, expected, x);
1566 }
1567
1568 @ForceInline
1569 public final <V> boolean weakCompareAndSetValue(Object o, long offset,
1570 Class<?> valueType,
1571 V expected,
1572 V x) {
1573 return compareAndSetValue(o, offset, valueType, expected, x);
1574 }
1575
1576 /**
1577 * Atomically updates Java variable to {@code x} if it is currently
1578 * holding {@code expected}.
1579 *
1580 * <p>This operation has memory semantics of a {@code volatile} read
1581 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1582 *
1583 * @return {@code true} if successful
1584 */
1585 @HotSpotIntrinsicCandidate
1586 public final native boolean compareAndSetInt(Object o, long offset,
1587 int expected,
1588 int x);
1589
1590 @HotSpotIntrinsicCandidate
1591 public final native int compareAndExchangeInt(Object o, long offset,
1592 int expected,
1593 int x);
1594
1595 @HotSpotIntrinsicCandidate
1596 public final int compareAndExchangeIntAcquire(Object o, long offset,
1597 int expected,
1598 int x) {
1599 return compareAndExchangeInt(o, offset, expected, x);
1600 }
1601
1602 @HotSpotIntrinsicCandidate
1603 public final int compareAndExchangeIntRelease(Object o, long offset,
1604 int expected,
1605 int x) {
1606 return compareAndExchangeInt(o, offset, expected, x);
1607 }
1608
1609 @HotSpotIntrinsicCandidate
1610 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1611 int expected,
1612 int x) {
1613 return compareAndSetInt(o, offset, expected, x);
1614 }
1615
1616 @HotSpotIntrinsicCandidate
1617 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1618 int expected,
1619 int x) {
1620 return compareAndSetInt(o, offset, expected, x);
1621 }
1622
1623 @HotSpotIntrinsicCandidate
1624 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1625 int expected,
1626 int x) {
1627 return compareAndSetInt(o, offset, expected, x);
1628 }
1629
1630 @HotSpotIntrinsicCandidate
1631 public final boolean weakCompareAndSetInt(Object o, long offset,
1632 int expected,
1633 int x) {
1634 return compareAndSetInt(o, offset, expected, x);
1635 }
1636
1637 @HotSpotIntrinsicCandidate
1638 public final byte compareAndExchangeByte(Object o, long offset,
1639 byte expected,
1640 byte x) {
1641 long wordOffset = offset & ~3;
1642 int shift = (int) (offset & 3) << 3;
1643 if (BE) {
1644 shift = 24 - shift;
1645 }
1646 int mask = 0xFF << shift;
1647 int maskedExpected = (expected & 0xFF) << shift;
1648 int maskedX = (x & 0xFF) << shift;
1649 int fullWord;
1650 do {
1651 fullWord = getIntVolatile(o, wordOffset);
1652 if ((fullWord & mask) != maskedExpected)
1653 return (byte) ((fullWord & mask) >> shift);
1654 } while (!weakCompareAndSetInt(o, wordOffset,
1655 fullWord, (fullWord & ~mask) | maskedX));
1656 return expected;
1657 }
1658
1659 @HotSpotIntrinsicCandidate
1660 public final boolean compareAndSetByte(Object o, long offset,
1661 byte expected,
1662 byte x) {
1663 return compareAndExchangeByte(o, offset, expected, x) == expected;
1664 }
1665
1666 @HotSpotIntrinsicCandidate
1667 public final boolean weakCompareAndSetByte(Object o, long offset,
1668 byte expected,
1669 byte x) {
1670 return compareAndSetByte(o, offset, expected, x);
1671 }
1672
1673 @HotSpotIntrinsicCandidate
1674 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1675 byte expected,
1676 byte x) {
1677 return weakCompareAndSetByte(o, offset, expected, x);
1678 }
1679
1680 @HotSpotIntrinsicCandidate
1681 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1682 byte expected,
1683 byte x) {
1684 return weakCompareAndSetByte(o, offset, expected, x);
1685 }
1686
1687 @HotSpotIntrinsicCandidate
1688 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1689 byte expected,
1690 byte x) {
1691 return weakCompareAndSetByte(o, offset, expected, x);
1692 }
1693
1694 @HotSpotIntrinsicCandidate
1695 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1696 byte expected,
1697 byte x) {
1698 return compareAndExchangeByte(o, offset, expected, x);
1699 }
1700
1701 @HotSpotIntrinsicCandidate
1702 public final byte compareAndExchangeByteRelease(Object o, long offset,
1703 byte expected,
1704 byte x) {
1705 return compareAndExchangeByte(o, offset, expected, x);
1706 }
1707
1708 @HotSpotIntrinsicCandidate
1709 public final short compareAndExchangeShort(Object o, long offset,
1710 short expected,
1711 short x) {
1712 if ((offset & 3) == 3) {
1713 throw new IllegalArgumentException("Update spans the word, not supported");
1714 }
1715 long wordOffset = offset & ~3;
1716 int shift = (int) (offset & 3) << 3;
1717 if (BE) {
1718 shift = 16 - shift;
1719 }
1720 int mask = 0xFFFF << shift;
1721 int maskedExpected = (expected & 0xFFFF) << shift;
1722 int maskedX = (x & 0xFFFF) << shift;
1723 int fullWord;
1724 do {
1725 fullWord = getIntVolatile(o, wordOffset);
1726 if ((fullWord & mask) != maskedExpected) {
1727 return (short) ((fullWord & mask) >> shift);
1728 }
1729 } while (!weakCompareAndSetInt(o, wordOffset,
1730 fullWord, (fullWord & ~mask) | maskedX));
1731 return expected;
1732 }
1733
1734 @HotSpotIntrinsicCandidate
1735 public final boolean compareAndSetShort(Object o, long offset,
1736 short expected,
1737 short x) {
1738 return compareAndExchangeShort(o, offset, expected, x) == expected;
1739 }
1740
1741 @HotSpotIntrinsicCandidate
1742 public final boolean weakCompareAndSetShort(Object o, long offset,
1743 short expected,
1744 short x) {
1745 return compareAndSetShort(o, offset, expected, x);
1746 }
1747
1748 @HotSpotIntrinsicCandidate
1749 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1750 short expected,
1751 short x) {
1752 return weakCompareAndSetShort(o, offset, expected, x);
1753 }
1754
1755 @HotSpotIntrinsicCandidate
1756 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1757 short expected,
1758 short x) {
1759 return weakCompareAndSetShort(o, offset, expected, x);
1760 }
1761
1762 @HotSpotIntrinsicCandidate
1763 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1764 short expected,
1765 short x) {
1766 return weakCompareAndSetShort(o, offset, expected, x);
1767 }
1768
1769
1770 @HotSpotIntrinsicCandidate
1771 public final short compareAndExchangeShortAcquire(Object o, long offset,
1772 short expected,
1773 short x) {
1774 return compareAndExchangeShort(o, offset, expected, x);
1775 }
1776
1777 @HotSpotIntrinsicCandidate
1778 public final short compareAndExchangeShortRelease(Object o, long offset,
1779 short expected,
1780 short x) {
1781 return compareAndExchangeShort(o, offset, expected, x);
1782 }
1783
1784 @ForceInline
1785 private char s2c(short s) {
1786 return (char) s;
1787 }
1788
1789 @ForceInline
1790 private short c2s(char s) {
1791 return (short) s;
1792 }
1793
1794 @ForceInline
1795 public final boolean compareAndSetChar(Object o, long offset,
1796 char expected,
1797 char x) {
1798 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1799 }
1800
1801 @ForceInline
1802 public final char compareAndExchangeChar(Object o, long offset,
1803 char expected,
1804 char x) {
1805 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1806 }
1807
1808 @ForceInline
1809 public final char compareAndExchangeCharAcquire(Object o, long offset,
1810 char expected,
1811 char x) {
1812 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1813 }
1814
1815 @ForceInline
1816 public final char compareAndExchangeCharRelease(Object o, long offset,
1817 char expected,
1818 char x) {
1819 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1820 }
1821
1822 @ForceInline
1823 public final boolean weakCompareAndSetChar(Object o, long offset,
1824 char expected,
1825 char x) {
1826 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1827 }
1828
1829 @ForceInline
1830 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1831 char expected,
1832 char x) {
1833 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1834 }
1835
1836 @ForceInline
1837 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1838 char expected,
1839 char x) {
1840 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1841 }
1842
1843 @ForceInline
1844 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1845 char expected,
1846 char x) {
1847 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1848 }
1849
1850 /**
1851 * The JVM converts integral values to boolean values using two
1852 * different conventions, byte testing against zero and truncation
1853 * to least-significant bit.
1854 *
1855 * <p>The JNI documents specify that, at least for returning
1856 * values from native methods, a Java boolean value is converted
1857 * to the value-set 0..1 by first truncating to a byte (0..255 or
1858 * maybe -128..127) and then testing against zero. Thus, Java
1859 * booleans in non-Java data structures are by convention
1860 * represented as 8-bit containers containing either zero (for
1861 * false) or any non-zero value (for true).
1862 *
1863 * <p>Java booleans in the heap are also stored in bytes, but are
1864 * strongly normalized to the value-set 0..1 (i.e., they are
1865 * truncated to the least-significant bit).
1866 *
1867 * <p>The main reason for having different conventions for
1868 * conversion is performance: Truncation to the least-significant
1869 * bit can be usually implemented with fewer (machine)
1870 * instructions than byte testing against zero.
1871 *
1872 * <p>A number of Unsafe methods load boolean values from the heap
1873 * as bytes. Unsafe converts those values according to the JNI
1874 * rules (i.e, using the "testing against zero" convention). The
1875 * method {@code byte2bool} implements that conversion.
1876 *
1877 * @param b the byte to be converted to boolean
1878 * @return the result of the conversion
1879 */
1880 @ForceInline
1881 private boolean byte2bool(byte b) {
1882 return b != 0;
1883 }
1884
1885 /**
1886 * Convert a boolean value to a byte. The return value is strongly
1887 * normalized to the value-set 0..1 (i.e., the value is truncated
1888 * to the least-significant bit). See {@link #byte2bool(byte)} for
1889 * more details on conversion conventions.
1890 *
1891 * @param b the boolean to be converted to byte (and then normalized)
1892 * @return the result of the conversion
1893 */
1894 @ForceInline
1895 private byte bool2byte(boolean b) {
1896 return b ? (byte)1 : (byte)0;
1897 }
1898
1899 @ForceInline
1900 public final boolean compareAndSetBoolean(Object o, long offset,
1901 boolean expected,
1902 boolean x) {
1903 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1904 }
1905
1906 @ForceInline
1907 public final boolean compareAndExchangeBoolean(Object o, long offset,
1908 boolean expected,
1909 boolean x) {
1910 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1911 }
1912
1913 @ForceInline
1914 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1915 boolean expected,
1916 boolean x) {
1917 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1918 }
1919
1920 @ForceInline
1921 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1922 boolean expected,
1923 boolean x) {
1924 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1925 }
1926
1927 @ForceInline
1928 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1929 boolean expected,
1930 boolean x) {
1931 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1932 }
1933
1934 @ForceInline
1935 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1936 boolean expected,
1937 boolean x) {
1938 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1939 }
1940
1941 @ForceInline
1942 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1943 boolean expected,
1944 boolean x) {
1945 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1946 }
1947
1948 @ForceInline
1949 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1950 boolean expected,
1951 boolean x) {
1952 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1953 }
1954
1955 /**
1956 * Atomically updates Java variable to {@code x} if it is currently
1957 * holding {@code expected}.
1958 *
1959 * <p>This operation has memory semantics of a {@code volatile} read
1960 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1961 *
1962 * @return {@code true} if successful
1963 */
1964 @ForceInline
1965 public final boolean compareAndSetFloat(Object o, long offset,
1966 float expected,
1967 float x) {
1968 return compareAndSetInt(o, offset,
1969 Float.floatToRawIntBits(expected),
1970 Float.floatToRawIntBits(x));
1971 }
1972
1973 @ForceInline
1974 public final float compareAndExchangeFloat(Object o, long offset,
1975 float expected,
1976 float x) {
1977 int w = compareAndExchangeInt(o, offset,
1978 Float.floatToRawIntBits(expected),
1979 Float.floatToRawIntBits(x));
1980 return Float.intBitsToFloat(w);
1981 }
1982
1983 @ForceInline
1984 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1985 float expected,
1986 float x) {
1987 int w = compareAndExchangeIntAcquire(o, offset,
1988 Float.floatToRawIntBits(expected),
1989 Float.floatToRawIntBits(x));
1990 return Float.intBitsToFloat(w);
1991 }
1992
1993 @ForceInline
1994 public final float compareAndExchangeFloatRelease(Object o, long offset,
1995 float expected,
1996 float x) {
1997 int w = compareAndExchangeIntRelease(o, offset,
1998 Float.floatToRawIntBits(expected),
1999 Float.floatToRawIntBits(x));
2000 return Float.intBitsToFloat(w);
2001 }
2002
2003 @ForceInline
2004 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
2005 float expected,
2006 float x) {
2007 return weakCompareAndSetIntPlain(o, offset,
2008 Float.floatToRawIntBits(expected),
2009 Float.floatToRawIntBits(x));
2010 }
2011
2012 @ForceInline
2013 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
2014 float expected,
2015 float x) {
2016 return weakCompareAndSetIntAcquire(o, offset,
2017 Float.floatToRawIntBits(expected),
2018 Float.floatToRawIntBits(x));
2019 }
2020
2021 @ForceInline
2022 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
2023 float expected,
2024 float x) {
2025 return weakCompareAndSetIntRelease(o, offset,
2026 Float.floatToRawIntBits(expected),
2027 Float.floatToRawIntBits(x));
2028 }
2029
2030 @ForceInline
2031 public final boolean weakCompareAndSetFloat(Object o, long offset,
2032 float expected,
2033 float x) {
2034 return weakCompareAndSetInt(o, offset,
2035 Float.floatToRawIntBits(expected),
2036 Float.floatToRawIntBits(x));
2037 }
2038
2039 /**
2040 * Atomically updates Java variable to {@code x} if it is currently
2041 * holding {@code expected}.
2042 *
2043 * <p>This operation has memory semantics of a {@code volatile} read
2044 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2045 *
2046 * @return {@code true} if successful
2047 */
2048 @ForceInline
2049 public final boolean compareAndSetDouble(Object o, long offset,
2050 double expected,
2051 double x) {
2052 return compareAndSetLong(o, offset,
2053 Double.doubleToRawLongBits(expected),
2054 Double.doubleToRawLongBits(x));
2055 }
2056
2057 @ForceInline
2058 public final double compareAndExchangeDouble(Object o, long offset,
2059 double expected,
2060 double x) {
2061 long w = compareAndExchangeLong(o, offset,
2062 Double.doubleToRawLongBits(expected),
2063 Double.doubleToRawLongBits(x));
2064 return Double.longBitsToDouble(w);
2065 }
2066
2067 @ForceInline
2068 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
2069 double expected,
2070 double x) {
2071 long w = compareAndExchangeLongAcquire(o, offset,
2072 Double.doubleToRawLongBits(expected),
2073 Double.doubleToRawLongBits(x));
2074 return Double.longBitsToDouble(w);
2075 }
2076
2077 @ForceInline
2078 public final double compareAndExchangeDoubleRelease(Object o, long offset,
2079 double expected,
2080 double x) {
2081 long w = compareAndExchangeLongRelease(o, offset,
2082 Double.doubleToRawLongBits(expected),
2083 Double.doubleToRawLongBits(x));
2084 return Double.longBitsToDouble(w);
2085 }
2086
2087 @ForceInline
2088 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
2089 double expected,
2090 double x) {
2091 return weakCompareAndSetLongPlain(o, offset,
2092 Double.doubleToRawLongBits(expected),
2093 Double.doubleToRawLongBits(x));
2094 }
2095
2096 @ForceInline
2097 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2098 double expected,
2099 double x) {
2100 return weakCompareAndSetLongAcquire(o, offset,
2101 Double.doubleToRawLongBits(expected),
2102 Double.doubleToRawLongBits(x));
2103 }
2104
2105 @ForceInline
2106 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2107 double expected,
2108 double x) {
2109 return weakCompareAndSetLongRelease(o, offset,
2110 Double.doubleToRawLongBits(expected),
2111 Double.doubleToRawLongBits(x));
2112 }
2113
2114 @ForceInline
2115 public final boolean weakCompareAndSetDouble(Object o, long offset,
2116 double expected,
2117 double x) {
2118 return weakCompareAndSetLong(o, offset,
2119 Double.doubleToRawLongBits(expected),
2120 Double.doubleToRawLongBits(x));
2121 }
2122
2123 /**
2124 * Atomically updates Java variable to {@code x} if it is currently
2125 * holding {@code expected}.
2126 *
2127 * <p>This operation has memory semantics of a {@code volatile} read
2128 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2129 *
2130 * @return {@code true} if successful
2131 */
2132 @HotSpotIntrinsicCandidate
2133 public final native boolean compareAndSetLong(Object o, long offset,
2134 long expected,
2135 long x);
2136
2137 @HotSpotIntrinsicCandidate
2138 public final native long compareAndExchangeLong(Object o, long offset,
2139 long expected,
2140 long x);
2141
2142 @HotSpotIntrinsicCandidate
2143 public final long compareAndExchangeLongAcquire(Object o, long offset,
2144 long expected,
2145 long x) {
2146 return compareAndExchangeLong(o, offset, expected, x);
2147 }
2148
2149 @HotSpotIntrinsicCandidate
2150 public final long compareAndExchangeLongRelease(Object o, long offset,
2151 long expected,
2152 long x) {
2153 return compareAndExchangeLong(o, offset, expected, x);
2154 }
2155
2156 @HotSpotIntrinsicCandidate
2157 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2158 long expected,
2159 long x) {
2160 return compareAndSetLong(o, offset, expected, x);
2161 }
2162
2163 @HotSpotIntrinsicCandidate
2164 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2165 long expected,
2166 long x) {
2167 return compareAndSetLong(o, offset, expected, x);
2168 }
2169
2170 @HotSpotIntrinsicCandidate
2171 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2172 long expected,
2173 long x) {
2174 return compareAndSetLong(o, offset, expected, x);
2175 }
2176
2177 @HotSpotIntrinsicCandidate
2178 public final boolean weakCompareAndSetLong(Object o, long offset,
2179 long expected,
2180 long x) {
2181 return compareAndSetLong(o, offset, expected, x);
2182 }
2183
2184 /**
2185 * Fetches a reference value from a given Java variable, with volatile
2186 * load semantics. Otherwise identical to {@link #getObject(Object, long)}
2187 */
2188 @HotSpotIntrinsicCandidate
2189 public native Object getObjectVolatile(Object o, long offset);
2190
2191 /**
2192 * Global lock for atomic and volatile strength access to any value of
2193 * a value type. This is a temporary workaround until better localized
2194 * atomic access mechanisms are supported for value types.
2195 */
2196 private static final Object valueLock = new Object();
2197
2198 public final <V> Object getValueVolatile(Object base, long offset, Class<?> valueType) {
2199 synchronized (valueLock) {
2200 return getValue(base, offset, valueType);
2201 }
2202 }
2203
2204 /**
2205 * Stores a reference value into a given Java variable, with
2206 * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
2207 */
2208 @HotSpotIntrinsicCandidate
2209 public native void putObjectVolatile(Object o, long offset, Object x);
2210
2211 public final <V> void putValueVolatile(Object o, long offset, Class<?> valueType, V x) {
2212 synchronized (valueLock) {
2213 putValue(o, offset, valueType, x);
2214 }
2215 }
2216
2217 /** Volatile version of {@link #getInt(Object, long)} */
2218 @HotSpotIntrinsicCandidate
2219 public native int getIntVolatile(Object o, long offset);
2220
2221 /** Volatile version of {@link #putInt(Object, long, int)} */
2222 @HotSpotIntrinsicCandidate
2223 public native void putIntVolatile(Object o, long offset, int x);
2224
2225 /** Volatile version of {@link #getBoolean(Object, long)} */
2226 @HotSpotIntrinsicCandidate
2227 public native boolean getBooleanVolatile(Object o, long offset);
2228
2229 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2230 @HotSpotIntrinsicCandidate
2231 public native void putBooleanVolatile(Object o, long offset, boolean x);
2232
2233 /** Volatile version of {@link #getByte(Object, long)} */
2234 @HotSpotIntrinsicCandidate
2235 public native byte getByteVolatile(Object o, long offset);
2236
2237 /** Volatile version of {@link #putByte(Object, long, byte)} */
2238 @HotSpotIntrinsicCandidate
2239 public native void putByteVolatile(Object o, long offset, byte x);
2240
2241 /** Volatile version of {@link #getShort(Object, long)} */
2242 @HotSpotIntrinsicCandidate
2243 public native short getShortVolatile(Object o, long offset);
2244
2245 /** Volatile version of {@link #putShort(Object, long, short)} */
2246 @HotSpotIntrinsicCandidate
2247 public native void putShortVolatile(Object o, long offset, short x);
2248
2249 /** Volatile version of {@link #getChar(Object, long)} */
2250 @HotSpotIntrinsicCandidate
2251 public native char getCharVolatile(Object o, long offset);
2252
2253 /** Volatile version of {@link #putChar(Object, long, char)} */
2254 @HotSpotIntrinsicCandidate
2255 public native void putCharVolatile(Object o, long offset, char x);
2256
2257 /** Volatile version of {@link #getLong(Object, long)} */
2258 @HotSpotIntrinsicCandidate
2259 public native long getLongVolatile(Object o, long offset);
2260
2261 /** Volatile version of {@link #putLong(Object, long, long)} */
2262 @HotSpotIntrinsicCandidate
2263 public native void putLongVolatile(Object o, long offset, long x);
2264
2265 /** Volatile version of {@link #getFloat(Object, long)} */
2266 @HotSpotIntrinsicCandidate
2267 public native float getFloatVolatile(Object o, long offset);
2268
2269 /** Volatile version of {@link #putFloat(Object, long, float)} */
2270 @HotSpotIntrinsicCandidate
2271 public native void putFloatVolatile(Object o, long offset, float x);
2272
2273 /** Volatile version of {@link #getDouble(Object, long)} */
2274 @HotSpotIntrinsicCandidate
2275 public native double getDoubleVolatile(Object o, long offset);
2276
2277 /** Volatile version of {@link #putDouble(Object, long, double)} */
2278 @HotSpotIntrinsicCandidate
2279 public native void putDoubleVolatile(Object o, long offset, double x);
2280
2281
2282
2283 /** Acquire version of {@link #getObjectVolatile(Object, long)} */
2284 @HotSpotIntrinsicCandidate
2285 public final Object getObjectAcquire(Object o, long offset) {
2286 return getObjectVolatile(o, offset);
2287 }
2288
2289 public final <V> Object getValueAcquire(Object base, long offset, Class<?> valueType) {
2290 return getValueVolatile(base, offset, valueType);
2291 }
2292
2293 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2294 @HotSpotIntrinsicCandidate
2295 public final boolean getBooleanAcquire(Object o, long offset) {
2296 return getBooleanVolatile(o, offset);
2297 }
2298
2299 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2300 @HotSpotIntrinsicCandidate
2301 public final byte getByteAcquire(Object o, long offset) {
2302 return getByteVolatile(o, offset);
2303 }
2304
2305 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2306 @HotSpotIntrinsicCandidate
2307 public final short getShortAcquire(Object o, long offset) {
2308 return getShortVolatile(o, offset);
2309 }
2310
2311 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2312 @HotSpotIntrinsicCandidate
2313 public final char getCharAcquire(Object o, long offset) {
2314 return getCharVolatile(o, offset);
2315 }
2316
2317 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2318 @HotSpotIntrinsicCandidate
2319 public final int getIntAcquire(Object o, long offset) {
2320 return getIntVolatile(o, offset);
2321 }
2322
2323 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2324 @HotSpotIntrinsicCandidate
2325 public final float getFloatAcquire(Object o, long offset) {
2326 return getFloatVolatile(o, offset);
2327 }
2328
2329 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2330 @HotSpotIntrinsicCandidate
2331 public final long getLongAcquire(Object o, long offset) {
2332 return getLongVolatile(o, offset);
2333 }
2334
2335 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2336 @HotSpotIntrinsicCandidate
2337 public final double getDoubleAcquire(Object o, long offset) {
2338 return getDoubleVolatile(o, offset);
2339 }
2340
2341 /*
2342 * Versions of {@link #putObjectVolatile(Object, long, Object)}
2343 * that do not guarantee immediate visibility of the store to
2344 * other threads. This method is generally only useful if the
2345 * underlying field is a Java volatile (or if an array cell, one
2346 * that is otherwise only accessed using volatile accesses).
2347 *
2348 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2349 */
2350
2351 /** Release version of {@link #putObjectVolatile(Object, long, Object)} */
2352 @HotSpotIntrinsicCandidate
2353 public final void putObjectRelease(Object o, long offset, Object x) {
2354 putObjectVolatile(o, offset, x);
2355 }
2356
2357 public final <V> void putValueRelease(Object o, long offset, Class<?> valueType, V x) {
2358 putValueVolatile(o, offset, valueType, x);
2359 }
2360
2361 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2362 @HotSpotIntrinsicCandidate
2363 public final void putBooleanRelease(Object o, long offset, boolean x) {
2364 putBooleanVolatile(o, offset, x);
2365 }
2366
2367 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2368 @HotSpotIntrinsicCandidate
2369 public final void putByteRelease(Object o, long offset, byte x) {
2370 putByteVolatile(o, offset, x);
2371 }
2372
2373 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2374 @HotSpotIntrinsicCandidate
2375 public final void putShortRelease(Object o, long offset, short x) {
2376 putShortVolatile(o, offset, x);
2377 }
2378
2379 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2380 @HotSpotIntrinsicCandidate
2381 public final void putCharRelease(Object o, long offset, char x) {
2382 putCharVolatile(o, offset, x);
2383 }
2384
2385 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2386 @HotSpotIntrinsicCandidate
2387 public final void putIntRelease(Object o, long offset, int x) {
2388 putIntVolatile(o, offset, x);
2389 }
2390
2391 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2392 @HotSpotIntrinsicCandidate
2393 public final void putFloatRelease(Object o, long offset, float x) {
2394 putFloatVolatile(o, offset, x);
2395 }
2396
2397 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2398 @HotSpotIntrinsicCandidate
2399 public final void putLongRelease(Object o, long offset, long x) {
2400 putLongVolatile(o, offset, x);
2401 }
2402
2403 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2404 @HotSpotIntrinsicCandidate
2405 public final void putDoubleRelease(Object o, long offset, double x) {
2406 putDoubleVolatile(o, offset, x);
2407 }
2408
2409 // ------------------------------ Opaque --------------------------------------
2410
2411 /** Opaque version of {@link #getObjectVolatile(Object, long)} */
2412 @HotSpotIntrinsicCandidate
2413 public final Object getObjectOpaque(Object o, long offset) {
2414 return getObjectVolatile(o, offset);
2415 }
2416
2417 public final <V> Object getValueOpaque(Object base, long offset, Class<?> valueType) {
2418 return getValueVolatile(base, offset, valueType);
2419 }
2420
2421 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2422 @HotSpotIntrinsicCandidate
2423 public final boolean getBooleanOpaque(Object o, long offset) {
2424 return getBooleanVolatile(o, offset);
2425 }
2426
2427 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2428 @HotSpotIntrinsicCandidate
2429 public final byte getByteOpaque(Object o, long offset) {
2430 return getByteVolatile(o, offset);
2431 }
2432
2433 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2434 @HotSpotIntrinsicCandidate
2435 public final short getShortOpaque(Object o, long offset) {
2436 return getShortVolatile(o, offset);
2437 }
2438
2439 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2440 @HotSpotIntrinsicCandidate
2441 public final char getCharOpaque(Object o, long offset) {
2442 return getCharVolatile(o, offset);
2443 }
2444
2445 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2446 @HotSpotIntrinsicCandidate
2447 public final int getIntOpaque(Object o, long offset) {
2448 return getIntVolatile(o, offset);
2449 }
2450
2451 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2452 @HotSpotIntrinsicCandidate
2453 public final float getFloatOpaque(Object o, long offset) {
2454 return getFloatVolatile(o, offset);
2455 }
2456
2457 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2458 @HotSpotIntrinsicCandidate
2459 public final long getLongOpaque(Object o, long offset) {
2460 return getLongVolatile(o, offset);
2461 }
2462
2463 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2464 @HotSpotIntrinsicCandidate
2465 public final double getDoubleOpaque(Object o, long offset) {
2466 return getDoubleVolatile(o, offset);
2467 }
2468
2469 /** Opaque version of {@link #putObjectVolatile(Object, long, Object)} */
2470 @HotSpotIntrinsicCandidate
2471 public final void putObjectOpaque(Object o, long offset, Object x) {
2472 putObjectVolatile(o, offset, x);
2473 }
2474
2475 public final <V> void putValueOpaque(Object o, long offset, Class<?> valueType, V x) {
2476 putValueVolatile(o, offset, valueType, x);
2477 }
2478
2479 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2480 @HotSpotIntrinsicCandidate
2481 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2482 putBooleanVolatile(o, offset, x);
2483 }
2484
2485 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2486 @HotSpotIntrinsicCandidate
2487 public final void putByteOpaque(Object o, long offset, byte x) {
2488 putByteVolatile(o, offset, x);
2489 }
2490
2491 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2492 @HotSpotIntrinsicCandidate
2493 public final void putShortOpaque(Object o, long offset, short x) {
2494 putShortVolatile(o, offset, x);
2495 }
2496
2497 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2498 @HotSpotIntrinsicCandidate
2499 public final void putCharOpaque(Object o, long offset, char x) {
2500 putCharVolatile(o, offset, x);
2501 }
2502
2503 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2504 @HotSpotIntrinsicCandidate
2505 public final void putIntOpaque(Object o, long offset, int x) {
2506 putIntVolatile(o, offset, x);
2507 }
2508
2509 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2510 @HotSpotIntrinsicCandidate
2511 public final void putFloatOpaque(Object o, long offset, float x) {
2512 putFloatVolatile(o, offset, x);
2513 }
2514
2515 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2516 @HotSpotIntrinsicCandidate
2517 public final void putLongOpaque(Object o, long offset, long x) {
2518 putLongVolatile(o, offset, x);
2519 }
2520
2521 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2522 @HotSpotIntrinsicCandidate
2523 public final void putDoubleOpaque(Object o, long offset, double x) {
2524 putDoubleVolatile(o, offset, x);
2525 }
2526
2527 /**
2528 * Unblocks the given thread blocked on {@code park}, or, if it is
2529 * not blocked, causes the subsequent call to {@code park} not to
2530 * block. Note: this operation is "unsafe" solely because the
2531 * caller must somehow ensure that the thread has not been
2532 * destroyed. Nothing special is usually required to ensure this
2533 * when called from Java (in which there will ordinarily be a live
2534 * reference to the thread) but this is not nearly-automatically
2535 * so when calling from native code.
2536 *
2537 * @param thread the thread to unpark.
2538 */
2539 @HotSpotIntrinsicCandidate
2540 public native void unpark(Object thread);
2541
2542 /**
2543 * Blocks current thread, returning when a balancing
2544 * {@code unpark} occurs, or a balancing {@code unpark} has
2545 * already occurred, or the thread is interrupted, or, if not
2546 * absolute and time is not zero, the given time nanoseconds have
2547 * elapsed, or if absolute, the given deadline in milliseconds
2548 * since Epoch has passed, or spuriously (i.e., returning for no
2549 * "reason"). Note: This operation is in the Unsafe class only
2550 * because {@code unpark} is, so it would be strange to place it
2551 * elsewhere.
2552 */
2553 @HotSpotIntrinsicCandidate
2554 public native void park(boolean isAbsolute, long time);
2555
2556 /**
2557 * Gets the load average in the system run queue assigned
2558 * to the available processors averaged over various periods of time.
2559 * This method retrieves the given {@code nelem} samples and
2560 * assigns to the elements of the given {@code loadavg} array.
2561 * The system imposes a maximum of 3 samples, representing
2562 * averages over the last 1, 5, and 15 minutes, respectively.
2563 *
2564 * @param loadavg an array of double of size nelems
2565 * @param nelems the number of samples to be retrieved and
2566 * must be 1 to 3.
2567 *
2568 * @return the number of samples actually retrieved; or -1
2569 * if the load average is unobtainable.
2570 */
2571 public int getLoadAverage(double[] loadavg, int nelems) {
2572 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2573 throw new ArrayIndexOutOfBoundsException();
2574 }
2575
2576 return getLoadAverage0(loadavg, nelems);
2577 }
2578
2579 // The following contain CAS-based Java implementations used on
2580 // platforms not supporting native instructions
2581
2582 /**
2583 * Atomically adds the given value to the current value of a field
2584 * or array element within the given object {@code o}
2585 * at the given {@code offset}.
2586 *
2587 * @param o object/array to update the field/element in
2588 * @param offset field/element offset
2589 * @param delta the value to add
2590 * @return the previous value
2591 * @since 1.8
2592 */
2593 @HotSpotIntrinsicCandidate
2594 public final int getAndAddInt(Object o, long offset, int delta) {
2595 int v;
2596 do {
2597 v = getIntVolatile(o, offset);
2598 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2599 return v;
2600 }
2601
2602 @ForceInline
2603 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2604 int v;
2605 do {
2606 v = getInt(o, offset);
2607 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2608 return v;
2609 }
2610
2611 @ForceInline
2612 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2613 int v;
2614 do {
2615 v = getIntAcquire(o, offset);
2616 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2617 return v;
2618 }
2619
2620 /**
2621 * Atomically adds the given value to the current value of a field
2622 * or array element within the given object {@code o}
2623 * at the given {@code offset}.
2624 *
2625 * @param o object/array to update the field/element in
2626 * @param offset field/element offset
2627 * @param delta the value to add
2628 * @return the previous value
2629 * @since 1.8
2630 */
2631 @HotSpotIntrinsicCandidate
2632 public final long getAndAddLong(Object o, long offset, long delta) {
2633 long v;
2634 do {
2635 v = getLongVolatile(o, offset);
2636 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2637 return v;
2638 }
2639
2640 @ForceInline
2641 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2642 long v;
2643 do {
2644 v = getLong(o, offset);
2645 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2646 return v;
2647 }
2648
2649 @ForceInline
2650 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2651 long v;
2652 do {
2653 v = getLongAcquire(o, offset);
2654 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2655 return v;
2656 }
2657
2658 @HotSpotIntrinsicCandidate
2659 public final byte getAndAddByte(Object o, long offset, byte delta) {
2660 byte v;
2661 do {
2662 v = getByteVolatile(o, offset);
2663 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2664 return v;
2665 }
2666
2667 @ForceInline
2668 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2669 byte v;
2670 do {
2671 v = getByte(o, offset);
2672 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2673 return v;
2674 }
2675
2676 @ForceInline
2677 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2678 byte v;
2679 do {
2680 v = getByteAcquire(o, offset);
2681 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2682 return v;
2683 }
2684
2685 @HotSpotIntrinsicCandidate
2686 public final short getAndAddShort(Object o, long offset, short delta) {
2687 short v;
2688 do {
2689 v = getShortVolatile(o, offset);
2690 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2691 return v;
2692 }
2693
2694 @ForceInline
2695 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2696 short v;
2697 do {
2698 v = getShort(o, offset);
2699 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2700 return v;
2701 }
2702
2703 @ForceInline
2704 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2705 short v;
2706 do {
2707 v = getShortAcquire(o, offset);
2708 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2709 return v;
2710 }
2711
2712 @ForceInline
2713 public final char getAndAddChar(Object o, long offset, char delta) {
2714 return (char) getAndAddShort(o, offset, (short) delta);
2715 }
2716
2717 @ForceInline
2718 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2719 return (char) getAndAddShortRelease(o, offset, (short) delta);
2720 }
2721
2722 @ForceInline
2723 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2724 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2725 }
2726
2727 @ForceInline
2728 public final float getAndAddFloat(Object o, long offset, float delta) {
2729 int expectedBits;
2730 float v;
2731 do {
2732 // Load and CAS with the raw bits to avoid issues with NaNs and
2733 // possible bit conversion from signaling NaNs to quiet NaNs that
2734 // may result in the loop not terminating.
2735 expectedBits = getIntVolatile(o, offset);
2736 v = Float.intBitsToFloat(expectedBits);
2737 } while (!weakCompareAndSetInt(o, offset,
2738 expectedBits, Float.floatToRawIntBits(v + delta)));
2739 return v;
2740 }
2741
2742 @ForceInline
2743 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2744 int expectedBits;
2745 float v;
2746 do {
2747 // Load and CAS with the raw bits to avoid issues with NaNs and
2748 // possible bit conversion from signaling NaNs to quiet NaNs that
2749 // may result in the loop not terminating.
2750 expectedBits = getInt(o, offset);
2751 v = Float.intBitsToFloat(expectedBits);
2752 } while (!weakCompareAndSetIntRelease(o, offset,
2753 expectedBits, Float.floatToRawIntBits(v + delta)));
2754 return v;
2755 }
2756
2757 @ForceInline
2758 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2759 int expectedBits;
2760 float v;
2761 do {
2762 // Load and CAS with the raw bits to avoid issues with NaNs and
2763 // possible bit conversion from signaling NaNs to quiet NaNs that
2764 // may result in the loop not terminating.
2765 expectedBits = getIntAcquire(o, offset);
2766 v = Float.intBitsToFloat(expectedBits);
2767 } while (!weakCompareAndSetIntAcquire(o, offset,
2768 expectedBits, Float.floatToRawIntBits(v + delta)));
2769 return v;
2770 }
2771
2772 @ForceInline
2773 public final double getAndAddDouble(Object o, long offset, double delta) {
2774 long expectedBits;
2775 double v;
2776 do {
2777 // Load and CAS with the raw bits to avoid issues with NaNs and
2778 // possible bit conversion from signaling NaNs to quiet NaNs that
2779 // may result in the loop not terminating.
2780 expectedBits = getLongVolatile(o, offset);
2781 v = Double.longBitsToDouble(expectedBits);
2782 } while (!weakCompareAndSetLong(o, offset,
2783 expectedBits, Double.doubleToRawLongBits(v + delta)));
2784 return v;
2785 }
2786
2787 @ForceInline
2788 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2789 long expectedBits;
2790 double v;
2791 do {
2792 // Load and CAS with the raw bits to avoid issues with NaNs and
2793 // possible bit conversion from signaling NaNs to quiet NaNs that
2794 // may result in the loop not terminating.
2795 expectedBits = getLong(o, offset);
2796 v = Double.longBitsToDouble(expectedBits);
2797 } while (!weakCompareAndSetLongRelease(o, offset,
2798 expectedBits, Double.doubleToRawLongBits(v + delta)));
2799 return v;
2800 }
2801
2802 @ForceInline
2803 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2804 long expectedBits;
2805 double v;
2806 do {
2807 // Load and CAS with the raw bits to avoid issues with NaNs and
2808 // possible bit conversion from signaling NaNs to quiet NaNs that
2809 // may result in the loop not terminating.
2810 expectedBits = getLongAcquire(o, offset);
2811 v = Double.longBitsToDouble(expectedBits);
2812 } while (!weakCompareAndSetLongAcquire(o, offset,
2813 expectedBits, Double.doubleToRawLongBits(v + delta)));
2814 return v;
2815 }
2816
2817 /**
2818 * Atomically exchanges the given value with the current value of
2819 * a field or array element within the given object {@code o}
2820 * at the given {@code offset}.
2821 *
2822 * @param o object/array to update the field/element in
2823 * @param offset field/element offset
2824 * @param newValue new value
2825 * @return the previous value
2826 * @since 1.8
2827 */
2828 @HotSpotIntrinsicCandidate
2829 public final int getAndSetInt(Object o, long offset, int newValue) {
2830 int v;
2831 do {
2832 v = getIntVolatile(o, offset);
2833 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2834 return v;
2835 }
2836
2837 @ForceInline
2838 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2839 int v;
2840 do {
2841 v = getInt(o, offset);
2842 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2843 return v;
2844 }
2845
2846 @ForceInline
2847 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2848 int v;
2849 do {
2850 v = getIntAcquire(o, offset);
2851 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2852 return v;
2853 }
2854
2855 /**
2856 * Atomically exchanges the given value with the current value of
2857 * a field or array element within the given object {@code o}
2858 * at the given {@code offset}.
2859 *
2860 * @param o object/array to update the field/element in
2861 * @param offset field/element offset
2862 * @param newValue new value
2863 * @return the previous value
2864 * @since 1.8
2865 */
2866 @HotSpotIntrinsicCandidate
2867 public final long getAndSetLong(Object o, long offset, long newValue) {
2868 long v;
2869 do {
2870 v = getLongVolatile(o, offset);
2871 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2872 return v;
2873 }
2874
2875 @ForceInline
2876 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2877 long v;
2878 do {
2879 v = getLong(o, offset);
2880 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2881 return v;
2882 }
2883
2884 @ForceInline
2885 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2886 long v;
2887 do {
2888 v = getLongAcquire(o, offset);
2889 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2890 return v;
2891 }
2892
2893 /**
2894 * Atomically exchanges the given reference value with the current
2895 * reference value of a field or array element within the given
2896 * object {@code o} at the given {@code offset}.
2897 *
2898 * @param o object/array to update the field/element in
2899 * @param offset field/element offset
2900 * @param newValue new value
2901 * @return the previous value
2902 * @since 1.8
2903 */
2904 @HotSpotIntrinsicCandidate
2905 public final Object getAndSetObject(Object o, long offset, Object newValue) {
2906 Object v;
2907 do {
2908 v = getObjectVolatile(o, offset);
2909 } while (!weakCompareAndSetObject(o, offset, v, newValue));
2910 return v;
2911 }
2912
2913 @SuppressWarnings("unchecked")
2914 public final <V> Object getAndSetValue(Object o, long offset, Class<?> valueType, V newValue) {
2915 synchronized (valueLock) {
2916 Object oldValue = getValue(o, offset, valueType);
2917 putValue(o, offset, valueType, newValue);
2918 return oldValue;
2919 }
2920 }
2921
2922 @ForceInline
2923 public final Object getAndSetObjectRelease(Object o, long offset, Object newValue) {
2924 Object v;
2925 do {
2926 v = getObject(o, offset);
2927 } while (!weakCompareAndSetObjectRelease(o, offset, v, newValue));
2928 return v;
2929 }
2930
2931 @ForceInline
2932 public final <V> Object getAndSetValueRelease(Object o, long offset, Class<?> valueType, V newValue) {
2933 return getAndSetValue(o, offset, valueType, newValue);
2934 }
2935
2936 @ForceInline
2937 public final Object getAndSetObjectAcquire(Object o, long offset, Object newValue) {
2938 Object v;
2939 do {
2940 v = getObjectAcquire(o, offset);
2941 } while (!weakCompareAndSetObjectAcquire(o, offset, v, newValue));
2942 return v;
2943 }
2944
2945 @ForceInline
2946 public final <V> Object getAndSetValueAcquire(Object o, long offset, Class<?> valueType, V newValue) {
2947 return getAndSetValue(o, offset, valueType, newValue);
2948 }
2949
2950 @HotSpotIntrinsicCandidate
2951 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2952 byte v;
2953 do {
2954 v = getByteVolatile(o, offset);
2955 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2956 return v;
2957 }
2958
2959 @ForceInline
2960 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2961 byte v;
2962 do {
2963 v = getByte(o, offset);
2964 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2965 return v;
2966 }
2967
2968 @ForceInline
2969 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2970 byte v;
2971 do {
2972 v = getByteAcquire(o, offset);
2973 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2974 return v;
2975 }
2976
2977 @ForceInline
2978 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2979 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2980 }
2981
2982 @ForceInline
2983 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2984 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2985 }
2986
2987 @ForceInline
2988 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2989 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2990 }
2991
2992 @HotSpotIntrinsicCandidate
2993 public final short getAndSetShort(Object o, long offset, short newValue) {
2994 short v;
2995 do {
2996 v = getShortVolatile(o, offset);
2997 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2998 return v;
2999 }
3000
3001 @ForceInline
3002 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
3003 short v;
3004 do {
3005 v = getShort(o, offset);
3006 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
3007 return v;
3008 }
3009
3010 @ForceInline
3011 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
3012 short v;
3013 do {
3014 v = getShortAcquire(o, offset);
3015 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
3016 return v;
3017 }
3018
3019 @ForceInline
3020 public final char getAndSetChar(Object o, long offset, char newValue) {
3021 return s2c(getAndSetShort(o, offset, c2s(newValue)));
3022 }
3023
3024 @ForceInline
3025 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
3026 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
3027 }
3028
3029 @ForceInline
3030 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
3031 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
3032 }
3033
3034 @ForceInline
3035 public final float getAndSetFloat(Object o, long offset, float newValue) {
3036 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
3037 return Float.intBitsToFloat(v);
3038 }
3039
3040 @ForceInline
3041 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
3042 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
3043 return Float.intBitsToFloat(v);
3044 }
3045
3046 @ForceInline
3047 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
3048 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
3049 return Float.intBitsToFloat(v);
3050 }
3051
3052 @ForceInline
3053 public final double getAndSetDouble(Object o, long offset, double newValue) {
3054 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
3055 return Double.longBitsToDouble(v);
3056 }
3057
3058 @ForceInline
3059 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
3060 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
3061 return Double.longBitsToDouble(v);
3062 }
3063
3064 @ForceInline
3065 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
3066 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
3067 return Double.longBitsToDouble(v);
3068 }
3069
3070
3071 // The following contain CAS-based Java implementations used on
3072 // platforms not supporting native instructions
3073
3074 @ForceInline
3075 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
3076 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
3077 }
3078
3079 @ForceInline
3080 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
3081 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
3082 }
3083
3084 @ForceInline
3085 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
3086 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
3087 }
3088
3089 @ForceInline
3090 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
3091 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
3092 }
3093
3094 @ForceInline
3095 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
3096 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
3097 }
3098
3099 @ForceInline
3100 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
3101 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
3102 }
3103
3104 @ForceInline
3105 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
3106 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
3107 }
3108
3109 @ForceInline
3110 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
3111 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
3112 }
3113
3114 @ForceInline
3115 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
3116 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
3117 }
3118
3119
3120 @ForceInline
3121 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
3122 byte current;
3123 do {
3124 current = getByteVolatile(o, offset);
3125 } while (!weakCompareAndSetByte(o, offset,
3126 current, (byte) (current | mask)));
3127 return current;
3128 }
3129
3130 @ForceInline
3131 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
3132 byte current;
3133 do {
3134 current = getByte(o, offset);
3135 } while (!weakCompareAndSetByteRelease(o, offset,
3136 current, (byte) (current | mask)));
3137 return current;
3138 }
3139
3140 @ForceInline
3141 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
3142 byte current;
3143 do {
3144 // Plain read, the value is a hint, the acquire CAS does the work
3145 current = getByte(o, offset);
3146 } while (!weakCompareAndSetByteAcquire(o, offset,
3147 current, (byte) (current | mask)));
3148 return current;
3149 }
3150
3151 @ForceInline
3152 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3153 byte current;
3154 do {
3155 current = getByteVolatile(o, offset);
3156 } while (!weakCompareAndSetByte(o, offset,
3157 current, (byte) (current & mask)));
3158 return current;
3159 }
3160
3161 @ForceInline
3162 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3163 byte current;
3164 do {
3165 current = getByte(o, offset);
3166 } while (!weakCompareAndSetByteRelease(o, offset,
3167 current, (byte) (current & mask)));
3168 return current;
3169 }
3170
3171 @ForceInline
3172 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3173 byte current;
3174 do {
3175 // Plain read, the value is a hint, the acquire CAS does the work
3176 current = getByte(o, offset);
3177 } while (!weakCompareAndSetByteAcquire(o, offset,
3178 current, (byte) (current & mask)));
3179 return current;
3180 }
3181
3182 @ForceInline
3183 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3184 byte current;
3185 do {
3186 current = getByteVolatile(o, offset);
3187 } while (!weakCompareAndSetByte(o, offset,
3188 current, (byte) (current ^ mask)));
3189 return current;
3190 }
3191
3192 @ForceInline
3193 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3194 byte current;
3195 do {
3196 current = getByte(o, offset);
3197 } while (!weakCompareAndSetByteRelease(o, offset,
3198 current, (byte) (current ^ mask)));
3199 return current;
3200 }
3201
3202 @ForceInline
3203 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3204 byte current;
3205 do {
3206 // Plain read, the value is a hint, the acquire CAS does the work
3207 current = getByte(o, offset);
3208 } while (!weakCompareAndSetByteAcquire(o, offset,
3209 current, (byte) (current ^ mask)));
3210 return current;
3211 }
3212
3213
3214 @ForceInline
3215 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3216 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3217 }
3218
3219 @ForceInline
3220 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3221 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3222 }
3223
3224 @ForceInline
3225 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3226 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3227 }
3228
3229 @ForceInline
3230 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3231 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3232 }
3233
3234 @ForceInline
3235 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3236 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3237 }
3238
3239 @ForceInline
3240 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3241 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3242 }
3243
3244 @ForceInline
3245 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3246 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3247 }
3248
3249 @ForceInline
3250 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3251 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3252 }
3253
3254 @ForceInline
3255 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3256 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3257 }
3258
3259
3260 @ForceInline
3261 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3262 short current;
3263 do {
3264 current = getShortVolatile(o, offset);
3265 } while (!weakCompareAndSetShort(o, offset,
3266 current, (short) (current | mask)));
3267 return current;
3268 }
3269
3270 @ForceInline
3271 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3272 short current;
3273 do {
3274 current = getShort(o, offset);
3275 } while (!weakCompareAndSetShortRelease(o, offset,
3276 current, (short) (current | mask)));
3277 return current;
3278 }
3279
3280 @ForceInline
3281 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3282 short current;
3283 do {
3284 // Plain read, the value is a hint, the acquire CAS does the work
3285 current = getShort(o, offset);
3286 } while (!weakCompareAndSetShortAcquire(o, offset,
3287 current, (short) (current | mask)));
3288 return current;
3289 }
3290
3291 @ForceInline
3292 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3293 short current;
3294 do {
3295 current = getShortVolatile(o, offset);
3296 } while (!weakCompareAndSetShort(o, offset,
3297 current, (short) (current & mask)));
3298 return current;
3299 }
3300
3301 @ForceInline
3302 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3303 short current;
3304 do {
3305 current = getShort(o, offset);
3306 } while (!weakCompareAndSetShortRelease(o, offset,
3307 current, (short) (current & mask)));
3308 return current;
3309 }
3310
3311 @ForceInline
3312 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3313 short current;
3314 do {
3315 // Plain read, the value is a hint, the acquire CAS does the work
3316 current = getShort(o, offset);
3317 } while (!weakCompareAndSetShortAcquire(o, offset,
3318 current, (short) (current & mask)));
3319 return current;
3320 }
3321
3322 @ForceInline
3323 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3324 short current;
3325 do {
3326 current = getShortVolatile(o, offset);
3327 } while (!weakCompareAndSetShort(o, offset,
3328 current, (short) (current ^ mask)));
3329 return current;
3330 }
3331
3332 @ForceInline
3333 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3334 short current;
3335 do {
3336 current = getShort(o, offset);
3337 } while (!weakCompareAndSetShortRelease(o, offset,
3338 current, (short) (current ^ mask)));
3339 return current;
3340 }
3341
3342 @ForceInline
3343 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3344 short current;
3345 do {
3346 // Plain read, the value is a hint, the acquire CAS does the work
3347 current = getShort(o, offset);
3348 } while (!weakCompareAndSetShortAcquire(o, offset,
3349 current, (short) (current ^ mask)));
3350 return current;
3351 }
3352
3353
3354 @ForceInline
3355 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3356 int current;
3357 do {
3358 current = getIntVolatile(o, offset);
3359 } while (!weakCompareAndSetInt(o, offset,
3360 current, current | mask));
3361 return current;
3362 }
3363
3364 @ForceInline
3365 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3366 int current;
3367 do {
3368 current = getInt(o, offset);
3369 } while (!weakCompareAndSetIntRelease(o, offset,
3370 current, current | mask));
3371 return current;
3372 }
3373
3374 @ForceInline
3375 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3376 int current;
3377 do {
3378 // Plain read, the value is a hint, the acquire CAS does the work
3379 current = getInt(o, offset);
3380 } while (!weakCompareAndSetIntAcquire(o, offset,
3381 current, current | mask));
3382 return current;
3383 }
3384
3385 /**
3386 * Atomically replaces the current value of a field or array element within
3387 * the given object with the result of bitwise AND between the current value
3388 * and mask.
3389 *
3390 * @param o object/array to update the field/element in
3391 * @param offset field/element offset
3392 * @param mask the mask value
3393 * @return the previous value
3394 * @since 1.9
3395 */
3396 @ForceInline
3397 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3398 int current;
3399 do {
3400 current = getIntVolatile(o, offset);
3401 } while (!weakCompareAndSetInt(o, offset,
3402 current, current & mask));
3403 return current;
3404 }
3405
3406 @ForceInline
3407 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3408 int current;
3409 do {
3410 current = getInt(o, offset);
3411 } while (!weakCompareAndSetIntRelease(o, offset,
3412 current, current & mask));
3413 return current;
3414 }
3415
3416 @ForceInline
3417 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3418 int current;
3419 do {
3420 // Plain read, the value is a hint, the acquire CAS does the work
3421 current = getInt(o, offset);
3422 } while (!weakCompareAndSetIntAcquire(o, offset,
3423 current, current & mask));
3424 return current;
3425 }
3426
3427 @ForceInline
3428 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3429 int current;
3430 do {
3431 current = getIntVolatile(o, offset);
3432 } while (!weakCompareAndSetInt(o, offset,
3433 current, current ^ mask));
3434 return current;
3435 }
3436
3437 @ForceInline
3438 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3439 int current;
3440 do {
3441 current = getInt(o, offset);
3442 } while (!weakCompareAndSetIntRelease(o, offset,
3443 current, current ^ mask));
3444 return current;
3445 }
3446
3447 @ForceInline
3448 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3449 int current;
3450 do {
3451 // Plain read, the value is a hint, the acquire CAS does the work
3452 current = getInt(o, offset);
3453 } while (!weakCompareAndSetIntAcquire(o, offset,
3454 current, current ^ mask));
3455 return current;
3456 }
3457
3458
3459 @ForceInline
3460 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3461 long current;
3462 do {
3463 current = getLongVolatile(o, offset);
3464 } while (!weakCompareAndSetLong(o, offset,
3465 current, current | mask));
3466 return current;
3467 }
3468
3469 @ForceInline
3470 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3471 long current;
3472 do {
3473 current = getLong(o, offset);
3474 } while (!weakCompareAndSetLongRelease(o, offset,
3475 current, current | mask));
3476 return current;
3477 }
3478
3479 @ForceInline
3480 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3481 long current;
3482 do {
3483 // Plain read, the value is a hint, the acquire CAS does the work
3484 current = getLong(o, offset);
3485 } while (!weakCompareAndSetLongAcquire(o, offset,
3486 current, current | mask));
3487 return current;
3488 }
3489
3490 @ForceInline
3491 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3492 long current;
3493 do {
3494 current = getLongVolatile(o, offset);
3495 } while (!weakCompareAndSetLong(o, offset,
3496 current, current & mask));
3497 return current;
3498 }
3499
3500 @ForceInline
3501 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3502 long current;
3503 do {
3504 current = getLong(o, offset);
3505 } while (!weakCompareAndSetLongRelease(o, offset,
3506 current, current & mask));
3507 return current;
3508 }
3509
3510 @ForceInline
3511 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3512 long current;
3513 do {
3514 // Plain read, the value is a hint, the acquire CAS does the work
3515 current = getLong(o, offset);
3516 } while (!weakCompareAndSetLongAcquire(o, offset,
3517 current, current & mask));
3518 return current;
3519 }
3520
3521 @ForceInline
3522 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3523 long current;
3524 do {
3525 current = getLongVolatile(o, offset);
3526 } while (!weakCompareAndSetLong(o, offset,
3527 current, current ^ mask));
3528 return current;
3529 }
3530
3531 @ForceInline
3532 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3533 long current;
3534 do {
3535 current = getLong(o, offset);
3536 } while (!weakCompareAndSetLongRelease(o, offset,
3537 current, current ^ mask));
3538 return current;
3539 }
3540
3541 @ForceInline
3542 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3543 long current;
3544 do {
3545 // Plain read, the value is a hint, the acquire CAS does the work
3546 current = getLong(o, offset);
3547 } while (!weakCompareAndSetLongAcquire(o, offset,
3548 current, current ^ mask));
3549 return current;
3550 }
3551
3552
3553
3554 /**
3555 * Ensures that loads before the fence will not be reordered with loads and
3556 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3557 *
3558 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3559 * (an "acquire fence").
3560 *
3561 * A pure LoadLoad fence is not provided, since the addition of LoadStore
3562 * is almost always desired, and most current hardware instructions that
3563 * provide a LoadLoad barrier also provide a LoadStore barrier for free.
3564 * @since 1.8
3565 */
3566 @HotSpotIntrinsicCandidate
3567 public native void loadFence();
3568
3569 /**
3570 * Ensures that loads and stores before the fence will not be reordered with
3571 * stores after the fence; a "StoreStore plus LoadStore barrier".
3572 *
3573 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3574 * (a "release fence").
3575 *
3576 * A pure StoreStore fence is not provided, since the addition of LoadStore
3577 * is almost always desired, and most current hardware instructions that
3578 * provide a StoreStore barrier also provide a LoadStore barrier for free.
3579 * @since 1.8
3580 */
3581 @HotSpotIntrinsicCandidate
3582 public native void storeFence();
3583
3584 /**
3585 * Ensures that loads and stores before the fence will not be reordered
3586 * with loads and stores after the fence. Implies the effects of both
3587 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3588 * barrier.
3589 *
3590 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3591 * @since 1.8
3592 */
3593 @HotSpotIntrinsicCandidate
3594 public native void fullFence();
3595
3596 /**
3597 * Ensures that loads before the fence will not be reordered with
3598 * loads after the fence.
3599 */
3600 public final void loadLoadFence() {
3601 loadFence();
3602 }
3603
3604 /**
3605 * Ensures that stores before the fence will not be reordered with
3606 * stores after the fence.
3607 */
3608 public final void storeStoreFence() {
3609 storeFence();
3610 }
3611
3612
3613 /**
3614 * Throws IllegalAccessError; for use by the VM for access control
3615 * error support.
3616 * @since 1.8
3617 */
3618 private static void throwIllegalAccessError() {
3619 throw new IllegalAccessError();
3620 }
3621
3622 /**
3623 * @return Returns true if the native byte ordering of this
3624 * platform is big-endian, false if it is little-endian.
3625 */
3626 public final boolean isBigEndian() { return BE; }
3627
3628 /**
3629 * @return Returns true if this platform is capable of performing
3630 * accesses at addresses which are not aligned for the type of the
3631 * primitive type being accessed, false otherwise.
3632 */
3633 public final boolean unalignedAccess() { return unalignedAccess; }
3634
3635 /**
3636 * Fetches a value at some byte offset into a given Java object.
3637 * More specifically, fetches a value within the given object
3638 * <code>o</code> at the given offset, or (if <code>o</code> is
3639 * null) from the memory address whose numerical value is the
3640 * given offset. <p>
3641 *
3642 * The specification of this method is the same as {@link
3643 * #getLong(Object, long)} except that the offset does not need to
3644 * have been obtained from {@link #objectFieldOffset} on the
3645 * {@link java.lang.reflect.Field} of some Java field. The value
3646 * in memory is raw data, and need not correspond to any Java
3647 * variable. Unless <code>o</code> is null, the value accessed
3648 * must be entirely within the allocated object. The endianness
3649 * of the value in memory is the endianness of the native platform.
3650 *
3651 * <p> The read will be atomic with respect to the largest power
3652 * of two that divides the GCD of the offset and the storage size.
3653 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3654 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3655 * respectively. There are no other guarantees of atomicity.
3656 * <p>
3657 * 8-byte atomicity is only guaranteed on platforms on which
3658 * support atomic accesses to longs.
3659 *
3660 * @param o Java heap object in which the value resides, if any, else
3661 * null
3662 * @param offset The offset in bytes from the start of the object
3663 * @return the value fetched from the indicated object
3664 * @throws RuntimeException No defined exceptions are thrown, not even
3665 * {@link NullPointerException}
3666 * @since 9
3667 */
3668 @HotSpotIntrinsicCandidate
3669 public final long getLongUnaligned(Object o, long offset) {
3670 if ((offset & 7) == 0) {
3671 return getLong(o, offset);
3672 } else if ((offset & 3) == 0) {
3673 return makeLong(getInt(o, offset),
3674 getInt(o, offset + 4));
3675 } else if ((offset & 1) == 0) {
3676 return makeLong(getShort(o, offset),
3677 getShort(o, offset + 2),
3678 getShort(o, offset + 4),
3679 getShort(o, offset + 6));
3680 } else {
3681 return makeLong(getByte(o, offset),
3682 getByte(o, offset + 1),
3683 getByte(o, offset + 2),
3684 getByte(o, offset + 3),
3685 getByte(o, offset + 4),
3686 getByte(o, offset + 5),
3687 getByte(o, offset + 6),
3688 getByte(o, offset + 7));
3689 }
3690 }
3691 /**
3692 * As {@link #getLongUnaligned(Object, long)} but with an
3693 * additional argument which specifies the endianness of the value
3694 * as stored in memory.
3695 *
3696 * @param o Java heap object in which the variable resides
3697 * @param offset The offset in bytes from the start of the object
3698 * @param bigEndian The endianness of the value
3699 * @return the value fetched from the indicated object
3700 * @since 9
3701 */
3702 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3703 return convEndian(bigEndian, getLongUnaligned(o, offset));
3704 }
3705
3706 /** @see #getLongUnaligned(Object, long) */
3707 @HotSpotIntrinsicCandidate
3708 public final int getIntUnaligned(Object o, long offset) {
3709 if ((offset & 3) == 0) {
3710 return getInt(o, offset);
3711 } else if ((offset & 1) == 0) {
3712 return makeInt(getShort(o, offset),
3713 getShort(o, offset + 2));
3714 } else {
3715 return makeInt(getByte(o, offset),
3716 getByte(o, offset + 1),
3717 getByte(o, offset + 2),
3718 getByte(o, offset + 3));
3719 }
3720 }
3721 /** @see #getLongUnaligned(Object, long, boolean) */
3722 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3723 return convEndian(bigEndian, getIntUnaligned(o, offset));
3724 }
3725
3726 /** @see #getLongUnaligned(Object, long) */
3727 @HotSpotIntrinsicCandidate
3728 public final short getShortUnaligned(Object o, long offset) {
3729 if ((offset & 1) == 0) {
3730 return getShort(o, offset);
3731 } else {
3732 return makeShort(getByte(o, offset),
3733 getByte(o, offset + 1));
3734 }
3735 }
3736 /** @see #getLongUnaligned(Object, long, boolean) */
3737 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3738 return convEndian(bigEndian, getShortUnaligned(o, offset));
3739 }
3740
3741 /** @see #getLongUnaligned(Object, long) */
3742 @HotSpotIntrinsicCandidate
3743 public final char getCharUnaligned(Object o, long offset) {
3744 if ((offset & 1) == 0) {
3745 return getChar(o, offset);
3746 } else {
3747 return (char)makeShort(getByte(o, offset),
3748 getByte(o, offset + 1));
3749 }
3750 }
3751
3752 /** @see #getLongUnaligned(Object, long, boolean) */
3753 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3754 return convEndian(bigEndian, getCharUnaligned(o, offset));
3755 }
3756
3757 /**
3758 * Stores a value at some byte offset into a given Java object.
3759 * <p>
3760 * The specification of this method is the same as {@link
3761 * #getLong(Object, long)} except that the offset does not need to
3762 * have been obtained from {@link #objectFieldOffset} on the
3763 * {@link java.lang.reflect.Field} of some Java field. The value
3764 * in memory is raw data, and need not correspond to any Java
3765 * variable. The endianness of the value in memory is the
3766 * endianness of the native platform.
3767 * <p>
3768 * The write will be atomic with respect to the largest power of
3769 * two that divides the GCD of the offset and the storage size.
3770 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3771 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3772 * respectively. There are no other guarantees of atomicity.
3773 * <p>
3774 * 8-byte atomicity is only guaranteed on platforms on which
3775 * support atomic accesses to longs.
3776 *
3777 * @param o Java heap object in which the value resides, if any, else
3778 * null
3779 * @param offset The offset in bytes from the start of the object
3780 * @param x the value to store
3781 * @throws RuntimeException No defined exceptions are thrown, not even
3782 * {@link NullPointerException}
3783 * @since 9
3784 */
3785 @HotSpotIntrinsicCandidate
3786 public final void putLongUnaligned(Object o, long offset, long x) {
3787 if ((offset & 7) == 0) {
3788 putLong(o, offset, x);
3789 } else if ((offset & 3) == 0) {
3790 putLongParts(o, offset,
3791 (int)(x >> 0),
3792 (int)(x >>> 32));
3793 } else if ((offset & 1) == 0) {
3794 putLongParts(o, offset,
3795 (short)(x >>> 0),
3796 (short)(x >>> 16),
3797 (short)(x >>> 32),
3798 (short)(x >>> 48));
3799 } else {
3800 putLongParts(o, offset,
3801 (byte)(x >>> 0),
3802 (byte)(x >>> 8),
3803 (byte)(x >>> 16),
3804 (byte)(x >>> 24),
3805 (byte)(x >>> 32),
3806 (byte)(x >>> 40),
3807 (byte)(x >>> 48),
3808 (byte)(x >>> 56));
3809 }
3810 }
3811
3812 /**
3813 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3814 * argument which specifies the endianness of the value as stored in memory.
3815 * @param o Java heap object in which the value resides
3816 * @param offset The offset in bytes from the start of the object
3817 * @param x the value to store
3818 * @param bigEndian The endianness of the value
3819 * @throws RuntimeException No defined exceptions are thrown, not even
3820 * {@link NullPointerException}
3821 * @since 9
3822 */
3823 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3824 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3825 }
3826
3827 /** @see #putLongUnaligned(Object, long, long) */
3828 @HotSpotIntrinsicCandidate
3829 public final void putIntUnaligned(Object o, long offset, int x) {
3830 if ((offset & 3) == 0) {
3831 putInt(o, offset, x);
3832 } else if ((offset & 1) == 0) {
3833 putIntParts(o, offset,
3834 (short)(x >> 0),
3835 (short)(x >>> 16));
3836 } else {
3837 putIntParts(o, offset,
3838 (byte)(x >>> 0),
3839 (byte)(x >>> 8),
3840 (byte)(x >>> 16),
3841 (byte)(x >>> 24));
3842 }
3843 }
3844 /** @see #putLongUnaligned(Object, long, long, boolean) */
3845 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3846 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3847 }
3848
3849 /** @see #putLongUnaligned(Object, long, long) */
3850 @HotSpotIntrinsicCandidate
3851 public final void putShortUnaligned(Object o, long offset, short x) {
3852 if ((offset & 1) == 0) {
3853 putShort(o, offset, x);
3854 } else {
3855 putShortParts(o, offset,
3856 (byte)(x >>> 0),
3857 (byte)(x >>> 8));
3858 }
3859 }
3860 /** @see #putLongUnaligned(Object, long, long, boolean) */
3861 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3862 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3863 }
3864
3865 /** @see #putLongUnaligned(Object, long, long) */
3866 @HotSpotIntrinsicCandidate
3867 public final void putCharUnaligned(Object o, long offset, char x) {
3868 putShortUnaligned(o, offset, (short)x);
3869 }
3870 /** @see #putLongUnaligned(Object, long, long, boolean) */
3871 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3872 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3873 }
3874
3875 // JVM interface methods
3876 // BE is true iff the native endianness of this platform is big.
3877 private static final boolean BE = theUnsafe.isBigEndian0();
3878
3879 // unalignedAccess is true iff this platform can perform unaligned accesses.
3880 private static final boolean unalignedAccess = theUnsafe.unalignedAccess0();
3881
3882 private static int pickPos(int top, int pos) { return BE ? top - pos : pos; }
3883
3884 // These methods construct integers from bytes. The byte ordering
3885 // is the native endianness of this platform.
3886 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3887 return ((toUnsignedLong(i0) << pickPos(56, 0))
3888 | (toUnsignedLong(i1) << pickPos(56, 8))
3889 | (toUnsignedLong(i2) << pickPos(56, 16))
3890 | (toUnsignedLong(i3) << pickPos(56, 24))
3891 | (toUnsignedLong(i4) << pickPos(56, 32))
3892 | (toUnsignedLong(i5) << pickPos(56, 40))
3893 | (toUnsignedLong(i6) << pickPos(56, 48))
3894 | (toUnsignedLong(i7) << pickPos(56, 56)));
3895 }
3896 private static long makeLong(short i0, short i1, short i2, short i3) {
3897 return ((toUnsignedLong(i0) << pickPos(48, 0))
3898 | (toUnsignedLong(i1) << pickPos(48, 16))
3899 | (toUnsignedLong(i2) << pickPos(48, 32))
3900 | (toUnsignedLong(i3) << pickPos(48, 48)));
3901 }
3902 private static long makeLong(int i0, int i1) {
3903 return (toUnsignedLong(i0) << pickPos(32, 0))
3904 | (toUnsignedLong(i1) << pickPos(32, 32));
3905 }
3906 private static int makeInt(short i0, short i1) {
3907 return (toUnsignedInt(i0) << pickPos(16, 0))
3908 | (toUnsignedInt(i1) << pickPos(16, 16));
3909 }
3910 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3911 return ((toUnsignedInt(i0) << pickPos(24, 0))
3912 | (toUnsignedInt(i1) << pickPos(24, 8))
3913 | (toUnsignedInt(i2) << pickPos(24, 16))
3914 | (toUnsignedInt(i3) << pickPos(24, 24)));
3915 }
3916 private static short makeShort(byte i0, byte i1) {
3917 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3918 | (toUnsignedInt(i1) << pickPos(8, 8)));
3919 }
3920
3921 private static byte pick(byte le, byte be) { return BE ? be : le; }
3922 private static short pick(short le, short be) { return BE ? be : le; }
3923 private static int pick(int le, int be) { return BE ? be : le; }
3924
3925 // These methods write integers to memory from smaller parts
3926 // provided by their caller. The ordering in which these parts
3927 // are written is the native endianness of this platform.
3928 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3929 putByte(o, offset + 0, pick(i0, i7));
3930 putByte(o, offset + 1, pick(i1, i6));
3931 putByte(o, offset + 2, pick(i2, i5));
3932 putByte(o, offset + 3, pick(i3, i4));
3933 putByte(o, offset + 4, pick(i4, i3));
3934 putByte(o, offset + 5, pick(i5, i2));
3935 putByte(o, offset + 6, pick(i6, i1));
3936 putByte(o, offset + 7, pick(i7, i0));
3937 }
3938 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3939 putShort(o, offset + 0, pick(i0, i3));
3940 putShort(o, offset + 2, pick(i1, i2));
3941 putShort(o, offset + 4, pick(i2, i1));
3942 putShort(o, offset + 6, pick(i3, i0));
3943 }
3944 private void putLongParts(Object o, long offset, int i0, int i1) {
3945 putInt(o, offset + 0, pick(i0, i1));
3946 putInt(o, offset + 4, pick(i1, i0));
3947 }
3948 private void putIntParts(Object o, long offset, short i0, short i1) {
3949 putShort(o, offset + 0, pick(i0, i1));
3950 putShort(o, offset + 2, pick(i1, i0));
3951 }
3952 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3953 putByte(o, offset + 0, pick(i0, i3));
3954 putByte(o, offset + 1, pick(i1, i2));
3955 putByte(o, offset + 2, pick(i2, i1));
3956 putByte(o, offset + 3, pick(i3, i0));
3957 }
3958 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3959 putByte(o, offset + 0, pick(i0, i1));
3960 putByte(o, offset + 1, pick(i1, i0));
3961 }
3962
3963 // Zero-extend an integer
3964 private static int toUnsignedInt(byte n) { return n & 0xff; }
3965 private static int toUnsignedInt(short n) { return n & 0xffff; }
3966 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3967 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3968 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3969
3970 // Maybe byte-reverse an integer
3971 private static char convEndian(boolean big, char n) { return big == BE ? n : Character.reverseBytes(n); }
3972 private static short convEndian(boolean big, short n) { return big == BE ? n : Short.reverseBytes(n) ; }
3973 private static int convEndian(boolean big, int n) { return big == BE ? n : Integer.reverseBytes(n) ; }
3974 private static long convEndian(boolean big, long n) { return big == BE ? n : Long.reverseBytes(n) ; }
3975
3976
3977
3978 private native long allocateMemory0(long bytes);
3979 private native long reallocateMemory0(long address, long bytes);
3980 private native void freeMemory0(long address);
3981 private native void setMemory0(Object o, long offset, long bytes, byte value);
3982 @HotSpotIntrinsicCandidate
3983 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3984 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3985 private native long objectFieldOffset0(Field f);
3986 private native long objectFieldOffset1(Class<?> c, String name);
3987 private native long staticFieldOffset0(Field f);
3988 private native Object staticFieldBase0(Field f);
3989 private native boolean shouldBeInitialized0(Class<?> c);
3990 private native void ensureClassInitialized0(Class<?> c);
3991 private native int arrayBaseOffset0(Class<?> arrayClass);
3992 private native int arrayIndexScale0(Class<?> arrayClass);
3993 private native int addressSize0();
3994 private native Class<?> defineAnonymousClass0(Class<?> hostClass, byte[] data, Object[] cpPatches);
3995 private native int getLoadAverage0(double[] loadavg, int nelems);
3996 private native boolean unalignedAccess0();
3997 private native boolean isBigEndian0();
3998 }