1 /*
2 * Copyright (c) 2000, 2021, 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.ref.Cleaner;
29 import jdk.internal.vm.annotation.ForceInline;
30 import jdk.internal.vm.annotation.IntrinsicCandidate;
31 import sun.nio.ch.DirectBuffer;
32
33 import java.lang.reflect.Field;
34 import java.security.ProtectionDomain;
35
36 import static jdk.internal.misc.UnsafeConstants.*;
37
38 /**
39 * A collection of methods for performing low-level, unsafe operations.
40 * Although the class and all methods are public, use of this class is
41 * limited because only trusted code can obtain instances of it.
42 *
43 * <em>Note:</em> It is the responsibility of the caller to make sure
44 * arguments are checked before methods of this class are
45 * called. While some rudimentary checks are performed on the input,
46 * the checks are best effort and when performance is an overriding
47 * priority, as when methods of this class are optimized by the
48 * runtime compiler, some or all checks (if any) may be elided. Hence,
49 * the caller must not rely on the checks and corresponding
50 * exceptions!
51 *
52 * @author John R. Rose
53 * @see #getUnsafe
54 */
55
56 public final class Unsafe {
57
58 private static native void registerNatives();
59 static {
60 registerNatives();
61 }
62
63 private Unsafe() {}
64
65 private static final Unsafe theUnsafe = new Unsafe();
66
67 /**
68 * Provides the caller with the capability of performing unsafe
69 * operations.
70 *
71 * <p>The returned {@code Unsafe} object should be carefully guarded
72 * by the caller, since it can be used to read and write data at arbitrary
73 * memory addresses. It must never be passed to untrusted code.
74 *
75 * <p>Most methods in this class are very low-level, and correspond to a
76 * small number of hardware instructions (on typical machines). Compilers
77 * are encouraged to optimize these methods accordingly.
78 *
79 * <p>Here is a suggested idiom for using unsafe operations:
80 *
81 * <pre> {@code
82 * class MyTrustedClass {
83 * private static final Unsafe unsafe = Unsafe.getUnsafe();
84 * ...
85 * private long myCountAddress = ...;
86 * public int getCount() { return unsafe.getByte(myCountAddress); }
87 * }}</pre>
88 *
89 * (It may assist compilers to make the local variable {@code final}.)
90 */
91 public static Unsafe getUnsafe() {
92 return theUnsafe;
93 }
94
95 /// peek and poke operations
96 /// (compilers should optimize these to memory ops)
97
98 // These work on object fields in the Java heap.
99 // They will not work on elements of packed arrays.
100
101 /**
102 * Fetches a value from a given Java variable.
103 * More specifically, fetches a field or array element within the given
104 * object {@code o} at the given offset, or (if {@code o} is null)
105 * from the memory address whose numerical value is the given offset.
106 * <p>
107 * The results are undefined unless one of the following cases is true:
108 * <ul>
109 * <li>The offset was obtained from {@link #objectFieldOffset} on
110 * the {@link java.lang.reflect.Field} of some Java field and the object
111 * referred to by {@code o} is of a class compatible with that
112 * field's class.
113 *
114 * <li>The offset and object reference {@code o} (either null or
115 * non-null) were both obtained via {@link #staticFieldOffset}
116 * and {@link #staticFieldBase} (respectively) from the
117 * reflective {@link Field} representation of some Java field.
118 *
119 * <li>The object referred to by {@code o} is an array, and the offset
120 * is an integer of the form {@code B+N*S}, where {@code N} is
121 * a valid index into the array, and {@code B} and {@code S} are
122 * the values obtained by {@link #arrayBaseOffset} and {@link
123 * #arrayIndexScale} (respectively) from the array's class. The value
124 * referred to is the {@code N}<em>th</em> element of the array.
125 *
126 * </ul>
127 * <p>
128 * If one of the above cases is true, the call references a specific Java
129 * variable (field or array element). However, the results are undefined
130 * if that variable is not in fact of the type returned by this method.
131 * <p>
132 * This method refers to a variable by means of two parameters, and so
133 * it provides (in effect) a <em>double-register</em> addressing mode
134 * for Java variables. When the object reference is null, this method
135 * uses its offset as an absolute address. This is similar in operation
136 * to methods such as {@link #getInt(long)}, which provide (in effect) a
137 * <em>single-register</em> addressing mode for non-Java variables.
138 * However, because Java variables may have a different layout in memory
139 * from non-Java variables, programmers should not assume that these
140 * two addressing modes are ever equivalent. Also, programmers should
141 * remember that offsets from the double-register addressing mode cannot
142 * be portably confused with longs used in the single-register addressing
143 * mode.
144 *
145 * @param o Java heap object in which the variable resides, if any, else
146 * null
147 * @param offset indication of where the variable resides in a Java heap
148 * object, if any, else a memory address locating the variable
149 * statically
150 * @return the value fetched from the indicated Java variable
151 * @throws RuntimeException No defined exceptions are thrown, not even
152 * {@link NullPointerException}
153 */
154 @IntrinsicCandidate
155 public native int getInt(Object o, long offset);
156
157 /**
158 * Stores a value into a given Java variable.
159 * <p>
160 * The first two parameters are interpreted exactly as with
161 * {@link #getInt(Object, long)} to refer to a specific
162 * Java variable (field or array element). The given value
163 * is stored into that variable.
164 * <p>
165 * The variable must be of the same type as the method
166 * parameter {@code x}.
167 *
168 * @param o Java heap object in which the variable resides, if any, else
169 * null
170 * @param offset indication of where the variable resides in a Java heap
171 * object, if any, else a memory address locating the variable
172 * statically
173 * @param x the value to store into the indicated Java variable
174 * @throws RuntimeException No defined exceptions are thrown, not even
175 * {@link NullPointerException}
176 */
177 @IntrinsicCandidate
178 public native void putInt(Object o, long offset, int x);
179
180 /**
181 * Fetches a reference value from a given Java variable.
182 * @see #getInt(Object, long)
183 */
184 @IntrinsicCandidate
185 public native Object getReference(Object o, long offset);
186
187 /**
188 * Stores a reference value into a given Java variable.
189 * <p>
190 * Unless the reference {@code x} being stored is either null
191 * or matches the field type, the results are undefined.
192 * If the reference {@code o} is non-null, card marks or
193 * other store barriers for that object (if the VM requires them)
194 * are updated.
195 * @see #putInt(Object, long, int)
196 */
197 @IntrinsicCandidate
198 public native void putReference(Object o, long offset, Object x);
199
200 /** @see #getInt(Object, long) */
201 @IntrinsicCandidate
202 public native boolean getBoolean(Object o, long offset);
203
204 /** @see #putInt(Object, long, int) */
205 @IntrinsicCandidate
206 public native void putBoolean(Object o, long offset, boolean x);
207
208 /** @see #getInt(Object, long) */
209 @IntrinsicCandidate
210 public native byte getByte(Object o, long offset);
211
212 /** @see #putInt(Object, long, int) */
213 @IntrinsicCandidate
214 public native void putByte(Object o, long offset, byte x);
215
216 /** @see #getInt(Object, long) */
217 @IntrinsicCandidate
218 public native short getShort(Object o, long offset);
219
220 /** @see #putInt(Object, long, int) */
221 @IntrinsicCandidate
222 public native void putShort(Object o, long offset, short x);
223
224 /** @see #getInt(Object, long) */
225 @IntrinsicCandidate
226 public native char getChar(Object o, long offset);
227
228 /** @see #putInt(Object, long, int) */
229 @IntrinsicCandidate
230 public native void putChar(Object o, long offset, char x);
231
232 /** @see #getInt(Object, long) */
233 @IntrinsicCandidate
234 public native long getLong(Object o, long offset);
235
236 /** @see #putInt(Object, long, int) */
237 @IntrinsicCandidate
238 public native void putLong(Object o, long offset, long x);
239
240 /** @see #getInt(Object, long) */
241 @IntrinsicCandidate
242 public native float getFloat(Object o, long offset);
243
244 /** @see #putInt(Object, long, int) */
245 @IntrinsicCandidate
246 public native void putFloat(Object o, long offset, float x);
247
248 /** @see #getInt(Object, long) */
249 @IntrinsicCandidate
250 public native double getDouble(Object o, long offset);
251
252 /** @see #putInt(Object, long, int) */
253 @IntrinsicCandidate
254 public native void putDouble(Object o, long offset, double x);
255
256 /**
257 * Fetches a native pointer from a given memory address. If the address is
258 * zero, or does not point into a block obtained from {@link
259 * #allocateMemory}, the results are undefined.
260 *
261 * <p>If the native pointer is less than 64 bits wide, it is extended as
262 * an unsigned number to a Java long. The pointer may be indexed by any
263 * given byte offset, simply by adding that offset (as a simple integer) to
264 * the long representing the pointer. The number of bytes actually read
265 * from the target address may be determined by consulting {@link
266 * #addressSize}.
267 *
268 * @see #allocateMemory
269 * @see #getInt(Object, long)
270 */
271 @ForceInline
272 public long getAddress(Object o, long offset) {
273 if (ADDRESS_SIZE == 4) {
274 return Integer.toUnsignedLong(getInt(o, offset));
275 } else {
276 return getLong(o, offset);
277 }
278 }
279
280 /**
281 * Stores a native pointer into a given memory address. If the address is
282 * zero, or does not point into a block obtained from {@link
283 * #allocateMemory}, the results are undefined.
284 *
285 * <p>The number of bytes actually written at the target address may be
286 * determined by consulting {@link #addressSize}.
287 *
288 * @see #allocateMemory
289 * @see #putInt(Object, long, int)
290 */
291 @ForceInline
292 public void putAddress(Object o, long offset, long x) {
293 if (ADDRESS_SIZE == 4) {
294 putInt(o, offset, (int)x);
295 } else {
296 putLong(o, offset, x);
297 }
298 }
299
300 // These read VM internal data.
301
302 /**
303 * Fetches an uncompressed reference value from a given native variable
304 * ignoring the VM's compressed references mode.
305 *
306 * @param address a memory address locating the variable
307 * @return the value fetched from the indicated native variable
308 */
309 public native Object getUncompressedObject(long address);
310
311 // These work on values in the C heap.
312
313 /**
314 * Fetches a value from a given memory address. If the address is zero, or
315 * does not point into a block obtained from {@link #allocateMemory}, the
316 * results are undefined.
317 *
318 * @see #allocateMemory
319 */
320 @ForceInline
321 public byte getByte(long address) {
322 return getByte(null, address);
323 }
324
325 /**
326 * Stores a value into a given memory address. If the address is zero, or
327 * does not point into a block obtained from {@link #allocateMemory}, the
328 * results are undefined.
329 *
330 * @see #getByte(long)
331 */
332 @ForceInline
333 public void putByte(long address, byte x) {
334 putByte(null, address, x);
335 }
336
337 /** @see #getByte(long) */
338 @ForceInline
339 public short getShort(long address) {
340 return getShort(null, address);
341 }
342
343 /** @see #putByte(long, byte) */
344 @ForceInline
345 public void putShort(long address, short x) {
346 putShort(null, address, x);
347 }
348
349 /** @see #getByte(long) */
350 @ForceInline
351 public char getChar(long address) {
352 return getChar(null, address);
353 }
354
355 /** @see #putByte(long, byte) */
356 @ForceInline
357 public void putChar(long address, char x) {
358 putChar(null, address, x);
359 }
360
361 /** @see #getByte(long) */
362 @ForceInline
363 public int getInt(long address) {
364 return getInt(null, address);
365 }
366
367 /** @see #putByte(long, byte) */
368 @ForceInline
369 public void putInt(long address, int x) {
370 putInt(null, address, x);
371 }
372
373 /** @see #getByte(long) */
374 @ForceInline
375 public long getLong(long address) {
376 return getLong(null, address);
377 }
378
379 /** @see #putByte(long, byte) */
380 @ForceInline
381 public void putLong(long address, long x) {
382 putLong(null, address, x);
383 }
384
385 /** @see #getByte(long) */
386 @ForceInline
387 public float getFloat(long address) {
388 return getFloat(null, address);
389 }
390
391 /** @see #putByte(long, byte) */
392 @ForceInline
393 public void putFloat(long address, float x) {
394 putFloat(null, address, x);
395 }
396
397 /** @see #getByte(long) */
398 @ForceInline
399 public double getDouble(long address) {
400 return getDouble(null, address);
401 }
402
403 /** @see #putByte(long, byte) */
404 @ForceInline
405 public void putDouble(long address, double x) {
406 putDouble(null, address, x);
407 }
408
409 /** @see #getAddress(Object, long) */
410 @ForceInline
411 public long getAddress(long address) {
412 return getAddress(null, address);
413 }
414
415 /** @see #putAddress(Object, long, long) */
416 @ForceInline
417 public void putAddress(long address, long x) {
418 putAddress(null, address, x);
419 }
420
421
422
423 /// helper methods for validating various types of objects/values
424
425 /**
426 * Create an exception reflecting that some of the input was invalid
427 *
428 * <em>Note:</em> It is the responsibility of the caller to make
429 * sure arguments are checked before the methods are called. While
430 * some rudimentary checks are performed on the input, the checks
431 * are best effort and when performance is an overriding priority,
432 * as when methods of this class are optimized by the runtime
433 * compiler, some or all checks (if any) may be elided. Hence, the
434 * caller must not rely on the checks and corresponding
435 * exceptions!
436 *
437 * @return an exception object
438 */
439 private RuntimeException invalidInput() {
440 return new IllegalArgumentException();
441 }
442
443 /**
444 * Check if a value is 32-bit clean (32 MSB are all zero)
445 *
446 * @param value the 64-bit value to check
447 *
448 * @return true if the value is 32-bit clean
449 */
450 private boolean is32BitClean(long value) {
451 return value >>> 32 == 0;
452 }
453
454 /**
455 * Check the validity of a size (the equivalent of a size_t)
456 *
457 * @throws RuntimeException if the size is invalid
458 * (<em>Note:</em> after optimization, invalid inputs may
459 * go undetected, which will lead to unpredictable
460 * behavior)
461 */
462 private void checkSize(long size) {
463 if (ADDRESS_SIZE == 4) {
464 // Note: this will also check for negative sizes
465 if (!is32BitClean(size)) {
466 throw invalidInput();
467 }
468 } else if (size < 0) {
469 throw invalidInput();
470 }
471 }
472
473 /**
474 * Check the validity of a native address (the equivalent of void*)
475 *
476 * @throws RuntimeException if the address is invalid
477 * (<em>Note:</em> after optimization, invalid inputs may
478 * go undetected, which will lead to unpredictable
479 * behavior)
480 */
481 private void checkNativeAddress(long address) {
482 if (ADDRESS_SIZE == 4) {
483 // Accept both zero and sign extended pointers. A valid
484 // pointer will, after the +1 below, either have produced
485 // the value 0x0 or 0x1. Masking off the low bit allows
486 // for testing against 0.
487 if ((((address >> 32) + 1) & ~1) != 0) {
488 throw invalidInput();
489 }
490 }
491 }
492
493 /**
494 * Check the validity of an offset, relative to a base object
495 *
496 * @param o the base object
497 * @param offset the offset to check
498 *
499 * @throws RuntimeException if the size is invalid
500 * (<em>Note:</em> after optimization, invalid inputs may
501 * go undetected, which will lead to unpredictable
502 * behavior)
503 */
504 private void checkOffset(Object o, long offset) {
505 if (ADDRESS_SIZE == 4) {
506 // Note: this will also check for negative offsets
507 if (!is32BitClean(offset)) {
508 throw invalidInput();
509 }
510 } else if (offset < 0) {
511 throw invalidInput();
512 }
513 }
514
515 /**
516 * Check the validity of a double-register pointer
517 *
518 * Note: This code deliberately does *not* check for NPE for (at
519 * least) three reasons:
520 *
521 * 1) NPE is not just NULL/0 - there is a range of values all
522 * resulting in an NPE, which is not trivial to check for
523 *
524 * 2) It is the responsibility of the callers of Unsafe methods
525 * to verify the input, so throwing an exception here is not really
526 * useful - passing in a NULL pointer is a critical error and the
527 * must not expect an exception to be thrown anyway.
528 *
529 * 3) the actual operations will detect NULL pointers anyway by
530 * means of traps and signals (like SIGSEGV).
531 *
532 * @param o Java heap object, or null
533 * @param offset indication of where the variable resides in a Java heap
534 * object, if any, else a memory address locating the variable
535 * statically
536 *
537 * @throws RuntimeException if the pointer is invalid
538 * (<em>Note:</em> after optimization, invalid inputs may
539 * go undetected, which will lead to unpredictable
540 * behavior)
541 */
542 private void checkPointer(Object o, long offset) {
543 if (o == null) {
544 checkNativeAddress(offset);
545 } else {
546 checkOffset(o, offset);
547 }
548 }
549
550 /**
551 * Check if a type is a primitive array type
552 *
553 * @param c the type to check
554 *
555 * @return true if the type is a primitive array type
556 */
557 private void checkPrimitiveArray(Class<?> c) {
558 Class<?> componentType = c.getComponentType();
559 if (componentType == null || !componentType.isPrimitive()) {
560 throw invalidInput();
561 }
562 }
563
564 /**
565 * Check that a pointer is a valid primitive array type pointer
566 *
567 * Note: pointers off-heap are considered to be primitive arrays
568 *
569 * @throws RuntimeException if the pointer is invalid
570 * (<em>Note:</em> after optimization, invalid inputs may
571 * go undetected, which will lead to unpredictable
572 * behavior)
573 */
574 private void checkPrimitivePointer(Object o, long offset) {
575 checkPointer(o, offset);
576
577 if (o != null) {
578 // If on heap, it must be a primitive array
579 checkPrimitiveArray(o.getClass());
580 }
581 }
582
583
584 /// wrappers for malloc, realloc, free:
585
586 /**
587 * Round up allocation size to a multiple of HeapWordSize.
588 */
589 private long alignToHeapWordSize(long bytes) {
590 if (bytes >= 0) {
591 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
592 } else {
593 throw invalidInput();
594 }
595 }
596
597 /**
598 * Allocates a new block of native memory, of the given size in bytes. The
599 * contents of the memory are uninitialized; they will generally be
600 * garbage. The resulting native pointer will never be zero, and will be
601 * aligned for all value types. Dispose of this memory by calling {@link
602 * #freeMemory}, or resize it with {@link #reallocateMemory}.
603 *
604 * <em>Note:</em> It is the responsibility of the caller to make
605 * sure arguments are checked before the methods are called. While
606 * some rudimentary checks are performed on the input, the checks
607 * are best effort and when performance is an overriding priority,
608 * as when methods of this class are optimized by the runtime
609 * compiler, some or all checks (if any) may be elided. Hence, the
610 * caller must not rely on the checks and corresponding
611 * exceptions!
612 *
613 * @throws RuntimeException if the size is negative or too large
614 * for the native size_t type
615 *
616 * @throws OutOfMemoryError if the allocation is refused by the system
617 *
618 * @see #getByte(long)
619 * @see #putByte(long, byte)
620 */
621 public long allocateMemory(long bytes) {
622 bytes = alignToHeapWordSize(bytes);
623
624 allocateMemoryChecks(bytes);
625
626 if (bytes == 0) {
627 return 0;
628 }
629
630 long p = allocateMemory0(bytes);
631 if (p == 0) {
632 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
633 }
634
635 return p;
636 }
637
638 /**
639 * Validate the arguments to allocateMemory
640 *
641 * @throws RuntimeException if the arguments are invalid
642 * (<em>Note:</em> after optimization, invalid inputs may
643 * go undetected, which will lead to unpredictable
644 * behavior)
645 */
646 private void allocateMemoryChecks(long bytes) {
647 checkSize(bytes);
648 }
649
650 /**
651 * Resizes a new block of native memory, to the given size in bytes. The
652 * contents of the new block past the size of the old block are
653 * uninitialized; they will generally be garbage. The resulting native
654 * pointer will be zero if and only if the requested size is zero. The
655 * resulting native pointer will be aligned for all value types. Dispose
656 * of this memory by calling {@link #freeMemory}, or resize it with {@link
657 * #reallocateMemory}. The address passed to this method may be null, in
658 * which case an allocation will be performed.
659 *
660 * <em>Note:</em> It is the responsibility of the caller to make
661 * sure arguments are checked before the methods are called. While
662 * some rudimentary checks are performed on the input, the checks
663 * are best effort and when performance is an overriding priority,
664 * as when methods of this class are optimized by the runtime
665 * compiler, some or all checks (if any) may be elided. Hence, the
666 * caller must not rely on the checks and corresponding
667 * exceptions!
668 *
669 * @throws RuntimeException if the size is negative or too large
670 * for the native size_t type
671 *
672 * @throws OutOfMemoryError if the allocation is refused by the system
673 *
674 * @see #allocateMemory
675 */
676 public long reallocateMemory(long address, long bytes) {
677 bytes = alignToHeapWordSize(bytes);
678
679 reallocateMemoryChecks(address, bytes);
680
681 if (bytes == 0) {
682 freeMemory(address);
683 return 0;
684 }
685
686 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
687 if (p == 0) {
688 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
689 }
690
691 return p;
692 }
693
694 /**
695 * Validate the arguments to reallocateMemory
696 *
697 * @throws RuntimeException if the arguments are invalid
698 * (<em>Note:</em> after optimization, invalid inputs may
699 * go undetected, which will lead to unpredictable
700 * behavior)
701 */
702 private void reallocateMemoryChecks(long address, long bytes) {
703 checkPointer(null, address);
704 checkSize(bytes);
705 }
706
707 /**
708 * Sets all bytes in a given block of memory to a fixed value
709 * (usually zero).
710 *
711 * <p>This method determines a block's base address by means of two parameters,
712 * and so it provides (in effect) a <em>double-register</em> addressing mode,
713 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
714 * the offset supplies an absolute base address.
715 *
716 * <p>The stores are in coherent (atomic) units of a size determined
717 * by the address and length parameters. If the effective address and
718 * length are all even modulo 8, the stores take place in 'long' units.
719 * If the effective address and length are (resp.) even modulo 4 or 2,
720 * the stores take place in units of 'int' or 'short'.
721 *
722 * <em>Note:</em> It is the responsibility of the caller to make
723 * sure arguments are checked before the methods are called. While
724 * some rudimentary checks are performed on the input, the checks
725 * are best effort and when performance is an overriding priority,
726 * as when methods of this class are optimized by the runtime
727 * compiler, some or all checks (if any) may be elided. Hence, the
728 * caller must not rely on the checks and corresponding
729 * exceptions!
730 *
731 * @throws RuntimeException if any of the arguments is invalid
732 *
733 * @since 1.7
734 */
735 public void setMemory(Object o, long offset, long bytes, byte value) {
736 setMemoryChecks(o, offset, bytes, value);
737
738 if (bytes == 0) {
739 return;
740 }
741
742 setMemory0(o, offset, bytes, value);
743 }
744
745 /**
746 * Sets all bytes in a given block of memory to a fixed value
747 * (usually zero). This provides a <em>single-register</em> addressing mode,
748 * as discussed in {@link #getInt(Object,long)}.
749 *
750 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
751 */
752 public void setMemory(long address, long bytes, byte value) {
753 setMemory(null, address, bytes, value);
754 }
755
756 /**
757 * Validate the arguments to setMemory
758 *
759 * @throws RuntimeException if the arguments are invalid
760 * (<em>Note:</em> after optimization, invalid inputs may
761 * go undetected, which will lead to unpredictable
762 * behavior)
763 */
764 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
765 checkPrimitivePointer(o, offset);
766 checkSize(bytes);
767 }
768
769 /**
770 * Sets all bytes in a given block of memory to a copy of another
771 * block.
772 *
773 * <p>This method determines each block's base address by means of two parameters,
774 * and so it provides (in effect) a <em>double-register</em> addressing mode,
775 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
776 * the offset supplies an absolute base address.
777 *
778 * <p>The transfers are in coherent (atomic) units of a size determined
779 * by the address and length parameters. If the effective addresses and
780 * length are all even modulo 8, the transfer takes place in 'long' units.
781 * If the effective addresses and length are (resp.) even modulo 4 or 2,
782 * the transfer takes place in units of 'int' or 'short'.
783 *
784 * <em>Note:</em> It is the responsibility of the caller to make
785 * sure arguments are checked before the methods are called. While
786 * some rudimentary checks are performed on the input, the checks
787 * are best effort and when performance is an overriding priority,
788 * as when methods of this class are optimized by the runtime
789 * compiler, some or all checks (if any) may be elided. Hence, the
790 * caller must not rely on the checks and corresponding
791 * exceptions!
792 *
793 * @throws RuntimeException if any of the arguments is invalid
794 *
795 * @since 1.7
796 */
797 public void copyMemory(Object srcBase, long srcOffset,
798 Object destBase, long destOffset,
799 long bytes) {
800 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
801
802 if (bytes == 0) {
803 return;
804 }
805
806 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
807 }
808
809 /**
810 * Sets all bytes in a given block of memory to a copy of another
811 * block. This provides a <em>single-register</em> addressing mode,
812 * as discussed in {@link #getInt(Object,long)}.
813 *
814 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
815 */
816 public void copyMemory(long srcAddress, long destAddress, long bytes) {
817 copyMemory(null, srcAddress, null, destAddress, bytes);
818 }
819
820 /**
821 * Validate the arguments to copyMemory
822 *
823 * @throws RuntimeException if any of the arguments is invalid
824 * (<em>Note:</em> after optimization, invalid inputs may
825 * go undetected, which will lead to unpredictable
826 * behavior)
827 */
828 private void copyMemoryChecks(Object srcBase, long srcOffset,
829 Object destBase, long destOffset,
830 long bytes) {
831 checkSize(bytes);
832 checkPrimitivePointer(srcBase, srcOffset);
833 checkPrimitivePointer(destBase, destOffset);
834 }
835
836 /**
837 * Copies all elements from one block of memory to another block,
838 * *unconditionally* byte swapping the elements on the fly.
839 *
840 * <p>This method determines each 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 * <em>Note:</em> It is the responsibility of the caller to make
846 * sure arguments are checked before the methods are called. While
847 * some rudimentary checks are performed on the input, the checks
848 * are best effort and when performance is an overriding priority,
849 * as when methods of this class are optimized by the runtime
850 * compiler, some or all checks (if any) may be elided. Hence, the
851 * caller must not rely on the checks and corresponding
852 * exceptions!
853 *
854 * @throws RuntimeException if any of the arguments is invalid
855 *
856 * @since 9
857 */
858 public void copySwapMemory(Object srcBase, long srcOffset,
859 Object destBase, long destOffset,
860 long bytes, long elemSize) {
861 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
862
863 if (bytes == 0) {
864 return;
865 }
866
867 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
868 }
869
870 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
871 Object destBase, long destOffset,
872 long bytes, long elemSize) {
873 checkSize(bytes);
874
875 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
876 throw invalidInput();
877 }
878 if (bytes % elemSize != 0) {
879 throw invalidInput();
880 }
881
882 checkPrimitivePointer(srcBase, srcOffset);
883 checkPrimitivePointer(destBase, destOffset);
884 }
885
886 /**
887 * Copies all elements from one block of memory to another block, byte swapping the
888 * elements on the fly.
889 *
890 * This provides a <em>single-register</em> addressing mode, as
891 * discussed in {@link #getInt(Object,long)}.
892 *
893 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
894 */
895 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
896 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
897 }
898
899 /**
900 * Disposes of a block of native memory, as obtained from {@link
901 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
902 * this method may be null, in which case no action is taken.
903 *
904 * <em>Note:</em> It is the responsibility of the caller to make
905 * sure arguments are checked before the methods are called. While
906 * some rudimentary checks are performed on the input, the checks
907 * are best effort and when performance is an overriding priority,
908 * as when methods of this class are optimized by the runtime
909 * compiler, some or all checks (if any) may be elided. Hence, the
910 * caller must not rely on the checks and corresponding
911 * exceptions!
912 *
913 * @throws RuntimeException if any of the arguments is invalid
914 *
915 * @see #allocateMemory
916 */
917 public void freeMemory(long address) {
918 freeMemoryChecks(address);
919
920 if (address == 0) {
921 return;
922 }
923
924 freeMemory0(address);
925 }
926
927 /**
928 * Validate the arguments to freeMemory
929 *
930 * @throws RuntimeException if the arguments are invalid
931 * (<em>Note:</em> after optimization, invalid inputs may
932 * go undetected, which will lead to unpredictable
933 * behavior)
934 */
935 private void freeMemoryChecks(long address) {
936 checkPointer(null, address);
937 }
938
939 /**
940 * Ensure writeback of a specified virtual memory address range
941 * from cache to physical memory. All bytes in the address range
942 * are guaranteed to have been written back to physical memory on
943 * return from this call i.e. subsequently executed store
944 * instructions are guaranteed not to be visible before the
945 * writeback is completed.
946 *
947 * @param address
948 * the lowest byte address that must be guaranteed written
949 * back to memory. bytes at lower addresses may also be
950 * written back.
951 *
952 * @param length
953 * the length in bytes of the region starting at address
954 * that must be guaranteed written back to memory.
955 *
956 * @throws RuntimeException if memory writeback is not supported
957 * on the current hardware of if the arguments are invalid.
958 * (<em>Note:</em> after optimization, invalid inputs may
959 * go undetected, which will lead to unpredictable
960 * behavior)
961 *
962 * @since 14
963 */
964
965 public void writebackMemory(long address, long length) {
966 checkWritebackEnabled();
967 checkWritebackMemory(address, length);
968
969 // perform any required pre-writeback barrier
970 writebackPreSync0();
971
972 // write back one cache line at a time
973 long line = dataCacheLineAlignDown(address);
974 long end = address + length;
975 while (line < end) {
976 writeback0(line);
977 line += dataCacheLineFlushSize();
978 }
979
980 // perform any required post-writeback barrier
981 writebackPostSync0();
982 }
983
984 /**
985 * Validate the arguments to writebackMemory
986 *
987 * @throws RuntimeException if the arguments are invalid
988 * (<em>Note:</em> after optimization, invalid inputs may
989 * go undetected, which will lead to unpredictable
990 * behavior)
991 */
992 private void checkWritebackMemory(long address, long length) {
993 checkNativeAddress(address);
994 checkSize(length);
995 }
996
997 /**
998 * Validate that the current hardware supports memory writeback.
999 * (<em>Note:</em> this is a belt and braces check. Clients are
1000 * expected to test whether writeback is enabled by calling
1001 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1002 * calling method {@link writeback #writeback} if it is disabled).
1003 *
1004 *
1005 * @throws RuntimeException if memory writeback is not supported
1006 */
1007 private void checkWritebackEnabled() {
1008 if (!isWritebackEnabled()) {
1009 throw new RuntimeException("writebackMemory not enabled!");
1010 }
1011 }
1012
1013 /**
1014 * force writeback of an individual cache line.
1015 *
1016 * @param address
1017 * the start address of the cache line to be written back
1018 */
1019 @IntrinsicCandidate
1020 private native void writeback0(long address);
1021
1022 /**
1023 * Serialize writeback operations relative to preceding memory writes.
1024 */
1025 @IntrinsicCandidate
1026 private native void writebackPreSync0();
1027
1028 /**
1029 * Serialize writeback operations relative to following memory writes.
1030 */
1031 @IntrinsicCandidate
1032 private native void writebackPostSync0();
1033
1034 /// random queries
1035
1036 /**
1037 * This constant differs from all results that will ever be returned from
1038 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1039 * or {@link #arrayBaseOffset}.
1040 */
1041 public static final int INVALID_FIELD_OFFSET = -1;
1042
1043 /**
1044 * Reports the location of a given field in the storage allocation of its
1045 * class. Do not expect to perform any sort of arithmetic on this offset;
1046 * it is just a cookie which is passed to the unsafe heap memory accessors.
1047 *
1048 * <p>Any given field will always have the same offset and base, and no
1049 * two distinct fields of the same class will ever have the same offset
1050 * and base.
1051 *
1052 * <p>As of 1.4.1, offsets for fields are represented as long values,
1053 * although the Sun JVM does not use the most significant 32 bits.
1054 * However, JVM implementations which store static fields at absolute
1055 * addresses can use long offsets and null base pointers to express
1056 * the field locations in a form usable by {@link #getInt(Object,long)}.
1057 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1058 * must preserve all bits of static field offsets.
1059 * @see #getInt(Object, long)
1060 */
1061 public long objectFieldOffset(Field f) {
1062 if (f == null) {
1063 throw new NullPointerException();
1064 }
1065
1066 return objectFieldOffset0(f);
1067 }
1068
1069 /**
1070 * Reports the location of the field with a given name in the storage
1071 * allocation of its class.
1072 *
1073 * @throws NullPointerException if any parameter is {@code null}.
1074 * @throws InternalError if there is no field named {@code name} declared
1075 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1076 * would throw {@code java.lang.NoSuchFieldException}.
1077 *
1078 * @see #objectFieldOffset(Field)
1079 */
1080 public long objectFieldOffset(Class<?> c, String name) {
1081 if (c == null || name == null) {
1082 throw new NullPointerException();
1083 }
1084
1085 return objectFieldOffset1(c, name);
1086 }
1087
1088 /**
1089 * Reports the location of a given static field, in conjunction with {@link
1090 * #staticFieldBase}.
1091 * <p>Do not expect to perform any sort of arithmetic on this offset;
1092 * it is just a cookie which is passed to the unsafe heap memory accessors.
1093 *
1094 * <p>Any given field will always have the same offset, and no two distinct
1095 * fields of the same class will ever have the same offset.
1096 *
1097 * <p>As of 1.4.1, offsets for fields are represented as long values,
1098 * although the Sun JVM does not use the most significant 32 bits.
1099 * It is hard to imagine a JVM technology which needs more than
1100 * a few bits to encode an offset within a non-array object,
1101 * However, for consistency with other methods in this class,
1102 * this method reports its result as a long value.
1103 * @see #getInt(Object, long)
1104 */
1105 public long staticFieldOffset(Field f) {
1106 if (f == null) {
1107 throw new NullPointerException();
1108 }
1109
1110 return staticFieldOffset0(f);
1111 }
1112
1113 /**
1114 * Reports the location of a given static field, in conjunction with {@link
1115 * #staticFieldOffset}.
1116 * <p>Fetch the base "Object", if any, with which static fields of the
1117 * given class can be accessed via methods like {@link #getInt(Object,
1118 * long)}. This value may be null. This value may refer to an object
1119 * which is a "cookie", not guaranteed to be a real Object, and it should
1120 * not be used in any way except as argument to the get and put routines in
1121 * this class.
1122 */
1123 public Object staticFieldBase(Field f) {
1124 if (f == null) {
1125 throw new NullPointerException();
1126 }
1127
1128 return staticFieldBase0(f);
1129 }
1130
1131 /**
1132 * Detects if the given class may need to be initialized. This is often
1133 * needed in conjunction with obtaining the static field base of a
1134 * class.
1135 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1136 */
1137 public boolean shouldBeInitialized(Class<?> c) {
1138 if (c == null) {
1139 throw new NullPointerException();
1140 }
1141
1142 return shouldBeInitialized0(c);
1143 }
1144
1145 /**
1146 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1147 * This is often needed in conjunction with obtaining the static field base
1148 * of a class.
1149 *
1150 * The call returns when either class {@code c} is fully initialized or
1151 * class {@code c} is being initialized and the call is performed from
1152 * the initializing thread. In the latter case a subsequent call to
1153 * {@link #shouldBeInitialized} will return {@code true}.
1154 */
1155 public void ensureClassInitialized(Class<?> c) {
1156 if (c == null) {
1157 throw new NullPointerException();
1158 }
1159
1160 ensureClassInitialized0(c);
1161 }
1162
1163 /**
1164 * Reports the offset of the first element in the storage allocation of a
1165 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1166 * for the same class, you may use that scale factor, together with this
1167 * base offset, to form new offsets to access elements of arrays of the
1168 * given class.
1169 *
1170 * @see #getInt(Object, long)
1171 * @see #putInt(Object, long, int)
1172 */
1173 public int arrayBaseOffset(Class<?> arrayClass) {
1174 if (arrayClass == null) {
1175 throw new NullPointerException();
1176 }
1177
1178 return arrayBaseOffset0(arrayClass);
1179 }
1180
1181
1182 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1183 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1184 = theUnsafe.arrayBaseOffset(boolean[].class);
1185
1186 /** The value of {@code arrayBaseOffset(byte[].class)} */
1187 public static final int ARRAY_BYTE_BASE_OFFSET
1188 = theUnsafe.arrayBaseOffset(byte[].class);
1189
1190 /** The value of {@code arrayBaseOffset(short[].class)} */
1191 public static final int ARRAY_SHORT_BASE_OFFSET
1192 = theUnsafe.arrayBaseOffset(short[].class);
1193
1194 /** The value of {@code arrayBaseOffset(char[].class)} */
1195 public static final int ARRAY_CHAR_BASE_OFFSET
1196 = theUnsafe.arrayBaseOffset(char[].class);
1197
1198 /** The value of {@code arrayBaseOffset(int[].class)} */
1199 public static final int ARRAY_INT_BASE_OFFSET
1200 = theUnsafe.arrayBaseOffset(int[].class);
1201
1202 /** The value of {@code arrayBaseOffset(long[].class)} */
1203 public static final int ARRAY_LONG_BASE_OFFSET
1204 = theUnsafe.arrayBaseOffset(long[].class);
1205
1206 /** The value of {@code arrayBaseOffset(float[].class)} */
1207 public static final int ARRAY_FLOAT_BASE_OFFSET
1208 = theUnsafe.arrayBaseOffset(float[].class);
1209
1210 /** The value of {@code arrayBaseOffset(double[].class)} */
1211 public static final int ARRAY_DOUBLE_BASE_OFFSET
1212 = theUnsafe.arrayBaseOffset(double[].class);
1213
1214 /** The value of {@code arrayBaseOffset(Object[].class)} */
1215 public static final int ARRAY_OBJECT_BASE_OFFSET
1216 = theUnsafe.arrayBaseOffset(Object[].class);
1217
1218 /**
1219 * Reports the scale factor for addressing elements in the storage
1220 * allocation of a given array class. However, arrays of "narrow" types
1221 * will generally not work properly with accessors like {@link
1222 * #getByte(Object, long)}, so the scale factor for such classes is reported
1223 * as zero.
1224 *
1225 * @see #arrayBaseOffset
1226 * @see #getInt(Object, long)
1227 * @see #putInt(Object, long, int)
1228 */
1229 public int arrayIndexScale(Class<?> arrayClass) {
1230 if (arrayClass == null) {
1231 throw new NullPointerException();
1232 }
1233
1234 return arrayIndexScale0(arrayClass);
1235 }
1236
1237
1238 /** The value of {@code arrayIndexScale(boolean[].class)} */
1239 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1240 = theUnsafe.arrayIndexScale(boolean[].class);
1241
1242 /** The value of {@code arrayIndexScale(byte[].class)} */
1243 public static final int ARRAY_BYTE_INDEX_SCALE
1244 = theUnsafe.arrayIndexScale(byte[].class);
1245
1246 /** The value of {@code arrayIndexScale(short[].class)} */
1247 public static final int ARRAY_SHORT_INDEX_SCALE
1248 = theUnsafe.arrayIndexScale(short[].class);
1249
1250 /** The value of {@code arrayIndexScale(char[].class)} */
1251 public static final int ARRAY_CHAR_INDEX_SCALE
1252 = theUnsafe.arrayIndexScale(char[].class);
1253
1254 /** The value of {@code arrayIndexScale(int[].class)} */
1255 public static final int ARRAY_INT_INDEX_SCALE
1256 = theUnsafe.arrayIndexScale(int[].class);
1257
1258 /** The value of {@code arrayIndexScale(long[].class)} */
1259 public static final int ARRAY_LONG_INDEX_SCALE
1260 = theUnsafe.arrayIndexScale(long[].class);
1261
1262 /** The value of {@code arrayIndexScale(float[].class)} */
1263 public static final int ARRAY_FLOAT_INDEX_SCALE
1264 = theUnsafe.arrayIndexScale(float[].class);
1265
1266 /** The value of {@code arrayIndexScale(double[].class)} */
1267 public static final int ARRAY_DOUBLE_INDEX_SCALE
1268 = theUnsafe.arrayIndexScale(double[].class);
1269
1270 /** The value of {@code arrayIndexScale(Object[].class)} */
1271 public static final int ARRAY_OBJECT_INDEX_SCALE
1272 = theUnsafe.arrayIndexScale(Object[].class);
1273
1274 /**
1275 * Reports the size in bytes of a native pointer, as stored via {@link
1276 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1277 * other primitive types (as stored in native memory blocks) is determined
1278 * fully by their information content.
1279 */
1280 public int addressSize() {
1281 return ADDRESS_SIZE;
1282 }
1283
1284 /** The value of {@code addressSize()} */
1285 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1286
1287 /**
1288 * Reports the size in bytes of a native memory page (whatever that is).
1289 * This value will always be a power of two.
1290 */
1291 public int pageSize() { return PAGE_SIZE; }
1292
1293 /**
1294 * Reports the size in bytes of a data cache line written back by
1295 * the hardware cache line flush operation available to the JVM or
1296 * 0 if data cache line flushing is not enabled.
1297 */
1298 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1299
1300 /**
1301 * Rounds down address to a data cache line boundary as
1302 * determined by {@link #dataCacheLineFlushSize}
1303 * @return the rounded down address
1304 */
1305 public long dataCacheLineAlignDown(long address) {
1306 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1307 }
1308
1309 /**
1310 * Returns true if data cache line writeback
1311 */
1312 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1313
1314 /// random trusted operations from JNI:
1315
1316 /**
1317 * Tells the VM to define a class, without security checks. By default, the
1318 * class loader and protection domain come from the caller's class.
1319 */
1320 public Class<?> defineClass(String name, byte[] b, int off, int len,
1321 ClassLoader loader,
1322 ProtectionDomain protectionDomain) {
1323 if (b == null) {
1324 throw new NullPointerException();
1325 }
1326 if (len < 0) {
1327 throw new ArrayIndexOutOfBoundsException();
1328 }
1329
1330 return defineClass0(name, b, off, len, loader, protectionDomain);
1331 }
1332
1333 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1334 ClassLoader loader,
1335 ProtectionDomain protectionDomain);
1336
1337 /**
1338 * Allocates an instance but does not run any constructor.
1339 * Initializes the class if it has not yet been.
1340 */
1341 @IntrinsicCandidate
1342 public native Object allocateInstance(Class<?> cls)
1343 throws InstantiationException;
1344
1345 /**
1346 * Allocates an array of a given type, but does not do zeroing.
1347 * <p>
1348 * This method should only be used in the very rare cases where a high-performance code
1349 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1350 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1351 * <p>
1352 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1353 * before allowing untrusted code, or code in other threads, to observe the reference
1354 * to the newly allocated array. In addition, the publication of the array reference must be
1355 * safe according to the Java Memory Model requirements.
1356 * <p>
1357 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1358 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1359 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1360 * or issuing a {@link #storeFence} before publishing the reference.
1361 * <p>
1362 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1363 * elements that could break heap integrity.
1364 *
1365 * @param componentType array component type to allocate
1366 * @param length array size to allocate
1367 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1368 * or the length is negative
1369 */
1370 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1371 if (componentType == null) {
1372 throw new IllegalArgumentException("Component type is null");
1373 }
1374 if (!componentType.isPrimitive()) {
1375 throw new IllegalArgumentException("Component type is not primitive");
1376 }
1377 if (length < 0) {
1378 throw new IllegalArgumentException("Negative length");
1379 }
1380 return allocateUninitializedArray0(componentType, length);
1381 }
1382
1383 @IntrinsicCandidate
1384 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1385 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1386 // return the zeroed arrays.
1387 if (componentType == byte.class) return new byte[length];
1388 if (componentType == boolean.class) return new boolean[length];
1389 if (componentType == short.class) return new short[length];
1390 if (componentType == char.class) return new char[length];
1391 if (componentType == int.class) return new int[length];
1392 if (componentType == float.class) return new float[length];
1393 if (componentType == long.class) return new long[length];
1394 if (componentType == double.class) return new double[length];
1395 return null;
1396 }
1397
1398 /** Throws the exception without telling the verifier. */
1399 public native void throwException(Throwable ee);
1400
1401 /**
1402 * Atomically updates Java variable to {@code x} if it is currently
1403 * holding {@code expected}.
1404 *
1405 * <p>This operation has memory semantics of a {@code volatile} read
1406 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1407 *
1408 * @return {@code true} if successful
1409 */
1410 @IntrinsicCandidate
1411 public final native boolean compareAndSetReference(Object o, long offset,
1412 Object expected,
1413 Object x);
1414
1415 @IntrinsicCandidate
1416 public final native Object compareAndExchangeReference(Object o, long offset,
1417 Object expected,
1418 Object x);
1419
1420 @IntrinsicCandidate
1421 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1422 Object expected,
1423 Object x) {
1424 return compareAndExchangeReference(o, offset, expected, x);
1425 }
1426
1427 @IntrinsicCandidate
1428 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1429 Object expected,
1430 Object x) {
1431 return compareAndExchangeReference(o, offset, expected, x);
1432 }
1433
1434 @IntrinsicCandidate
1435 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1436 Object expected,
1437 Object x) {
1438 return compareAndSetReference(o, offset, expected, x);
1439 }
1440
1441 @IntrinsicCandidate
1442 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1443 Object expected,
1444 Object x) {
1445 return compareAndSetReference(o, offset, expected, x);
1446 }
1447
1448 @IntrinsicCandidate
1449 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1450 Object expected,
1451 Object x) {
1452 return compareAndSetReference(o, offset, expected, x);
1453 }
1454
1455 @IntrinsicCandidate
1456 public final boolean weakCompareAndSetReference(Object o, long offset,
1457 Object expected,
1458 Object x) {
1459 return compareAndSetReference(o, offset, expected, x);
1460 }
1461
1462 /**
1463 * Atomically updates Java variable to {@code x} if it is currently
1464 * holding {@code expected}.
1465 *
1466 * <p>This operation has memory semantics of a {@code volatile} read
1467 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1468 *
1469 * @return {@code true} if successful
1470 */
1471 @IntrinsicCandidate
1472 public final native boolean compareAndSetInt(Object o, long offset,
1473 int expected,
1474 int x);
1475
1476 @IntrinsicCandidate
1477 public final native int compareAndExchangeInt(Object o, long offset,
1478 int expected,
1479 int x);
1480
1481 @IntrinsicCandidate
1482 public final int compareAndExchangeIntAcquire(Object o, long offset,
1483 int expected,
1484 int x) {
1485 return compareAndExchangeInt(o, offset, expected, x);
1486 }
1487
1488 @IntrinsicCandidate
1489 public final int compareAndExchangeIntRelease(Object o, long offset,
1490 int expected,
1491 int x) {
1492 return compareAndExchangeInt(o, offset, expected, x);
1493 }
1494
1495 @IntrinsicCandidate
1496 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1497 int expected,
1498 int x) {
1499 return compareAndSetInt(o, offset, expected, x);
1500 }
1501
1502 @IntrinsicCandidate
1503 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1504 int expected,
1505 int x) {
1506 return compareAndSetInt(o, offset, expected, x);
1507 }
1508
1509 @IntrinsicCandidate
1510 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1511 int expected,
1512 int x) {
1513 return compareAndSetInt(o, offset, expected, x);
1514 }
1515
1516 @IntrinsicCandidate
1517 public final boolean weakCompareAndSetInt(Object o, long offset,
1518 int expected,
1519 int x) {
1520 return compareAndSetInt(o, offset, expected, x);
1521 }
1522
1523 @IntrinsicCandidate
1524 public final byte compareAndExchangeByte(Object o, long offset,
1525 byte expected,
1526 byte x) {
1527 long wordOffset = offset & ~3;
1528 int shift = (int) (offset & 3) << 3;
1529 if (BIG_ENDIAN) {
1530 shift = 24 - shift;
1531 }
1532 int mask = 0xFF << shift;
1533 int maskedExpected = (expected & 0xFF) << shift;
1534 int maskedX = (x & 0xFF) << shift;
1535 int fullWord;
1536 do {
1537 fullWord = getIntVolatile(o, wordOffset);
1538 if ((fullWord & mask) != maskedExpected)
1539 return (byte) ((fullWord & mask) >> shift);
1540 } while (!weakCompareAndSetInt(o, wordOffset,
1541 fullWord, (fullWord & ~mask) | maskedX));
1542 return expected;
1543 }
1544
1545 @IntrinsicCandidate
1546 public final boolean compareAndSetByte(Object o, long offset,
1547 byte expected,
1548 byte x) {
1549 return compareAndExchangeByte(o, offset, expected, x) == expected;
1550 }
1551
1552 @IntrinsicCandidate
1553 public final boolean weakCompareAndSetByte(Object o, long offset,
1554 byte expected,
1555 byte x) {
1556 return compareAndSetByte(o, offset, expected, x);
1557 }
1558
1559 @IntrinsicCandidate
1560 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1561 byte expected,
1562 byte x) {
1563 return weakCompareAndSetByte(o, offset, expected, x);
1564 }
1565
1566 @IntrinsicCandidate
1567 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1568 byte expected,
1569 byte x) {
1570 return weakCompareAndSetByte(o, offset, expected, x);
1571 }
1572
1573 @IntrinsicCandidate
1574 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1575 byte expected,
1576 byte x) {
1577 return weakCompareAndSetByte(o, offset, expected, x);
1578 }
1579
1580 @IntrinsicCandidate
1581 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1582 byte expected,
1583 byte x) {
1584 return compareAndExchangeByte(o, offset, expected, x);
1585 }
1586
1587 @IntrinsicCandidate
1588 public final byte compareAndExchangeByteRelease(Object o, long offset,
1589 byte expected,
1590 byte x) {
1591 return compareAndExchangeByte(o, offset, expected, x);
1592 }
1593
1594 @IntrinsicCandidate
1595 public final short compareAndExchangeShort(Object o, long offset,
1596 short expected,
1597 short x) {
1598 if ((offset & 3) == 3) {
1599 throw new IllegalArgumentException("Update spans the word, not supported");
1600 }
1601 long wordOffset = offset & ~3;
1602 int shift = (int) (offset & 3) << 3;
1603 if (BIG_ENDIAN) {
1604 shift = 16 - shift;
1605 }
1606 int mask = 0xFFFF << shift;
1607 int maskedExpected = (expected & 0xFFFF) << shift;
1608 int maskedX = (x & 0xFFFF) << shift;
1609 int fullWord;
1610 do {
1611 fullWord = getIntVolatile(o, wordOffset);
1612 if ((fullWord & mask) != maskedExpected) {
1613 return (short) ((fullWord & mask) >> shift);
1614 }
1615 } while (!weakCompareAndSetInt(o, wordOffset,
1616 fullWord, (fullWord & ~mask) | maskedX));
1617 return expected;
1618 }
1619
1620 @IntrinsicCandidate
1621 public final boolean compareAndSetShort(Object o, long offset,
1622 short expected,
1623 short x) {
1624 return compareAndExchangeShort(o, offset, expected, x) == expected;
1625 }
1626
1627 @IntrinsicCandidate
1628 public final boolean weakCompareAndSetShort(Object o, long offset,
1629 short expected,
1630 short x) {
1631 return compareAndSetShort(o, offset, expected, x);
1632 }
1633
1634 @IntrinsicCandidate
1635 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1636 short expected,
1637 short x) {
1638 return weakCompareAndSetShort(o, offset, expected, x);
1639 }
1640
1641 @IntrinsicCandidate
1642 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1643 short expected,
1644 short x) {
1645 return weakCompareAndSetShort(o, offset, expected, x);
1646 }
1647
1648 @IntrinsicCandidate
1649 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1650 short expected,
1651 short x) {
1652 return weakCompareAndSetShort(o, offset, expected, x);
1653 }
1654
1655
1656 @IntrinsicCandidate
1657 public final short compareAndExchangeShortAcquire(Object o, long offset,
1658 short expected,
1659 short x) {
1660 return compareAndExchangeShort(o, offset, expected, x);
1661 }
1662
1663 @IntrinsicCandidate
1664 public final short compareAndExchangeShortRelease(Object o, long offset,
1665 short expected,
1666 short x) {
1667 return compareAndExchangeShort(o, offset, expected, x);
1668 }
1669
1670 @ForceInline
1671 private char s2c(short s) {
1672 return (char) s;
1673 }
1674
1675 @ForceInline
1676 private short c2s(char s) {
1677 return (short) s;
1678 }
1679
1680 @ForceInline
1681 public final boolean compareAndSetChar(Object o, long offset,
1682 char expected,
1683 char x) {
1684 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1685 }
1686
1687 @ForceInline
1688 public final char compareAndExchangeChar(Object o, long offset,
1689 char expected,
1690 char x) {
1691 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1692 }
1693
1694 @ForceInline
1695 public final char compareAndExchangeCharAcquire(Object o, long offset,
1696 char expected,
1697 char x) {
1698 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1699 }
1700
1701 @ForceInline
1702 public final char compareAndExchangeCharRelease(Object o, long offset,
1703 char expected,
1704 char x) {
1705 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1706 }
1707
1708 @ForceInline
1709 public final boolean weakCompareAndSetChar(Object o, long offset,
1710 char expected,
1711 char x) {
1712 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1713 }
1714
1715 @ForceInline
1716 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1717 char expected,
1718 char x) {
1719 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1720 }
1721
1722 @ForceInline
1723 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1724 char expected,
1725 char x) {
1726 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1727 }
1728
1729 @ForceInline
1730 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1731 char expected,
1732 char x) {
1733 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1734 }
1735
1736 /**
1737 * The JVM converts integral values to boolean values using two
1738 * different conventions, byte testing against zero and truncation
1739 * to least-significant bit.
1740 *
1741 * <p>The JNI documents specify that, at least for returning
1742 * values from native methods, a Java boolean value is converted
1743 * to the value-set 0..1 by first truncating to a byte (0..255 or
1744 * maybe -128..127) and then testing against zero. Thus, Java
1745 * booleans in non-Java data structures are by convention
1746 * represented as 8-bit containers containing either zero (for
1747 * false) or any non-zero value (for true).
1748 *
1749 * <p>Java booleans in the heap are also stored in bytes, but are
1750 * strongly normalized to the value-set 0..1 (i.e., they are
1751 * truncated to the least-significant bit).
1752 *
1753 * <p>The main reason for having different conventions for
1754 * conversion is performance: Truncation to the least-significant
1755 * bit can be usually implemented with fewer (machine)
1756 * instructions than byte testing against zero.
1757 *
1758 * <p>A number of Unsafe methods load boolean values from the heap
1759 * as bytes. Unsafe converts those values according to the JNI
1760 * rules (i.e, using the "testing against zero" convention). The
1761 * method {@code byte2bool} implements that conversion.
1762 *
1763 * @param b the byte to be converted to boolean
1764 * @return the result of the conversion
1765 */
1766 @ForceInline
1767 private boolean byte2bool(byte b) {
1768 return b != 0;
1769 }
1770
1771 /**
1772 * Convert a boolean value to a byte. The return value is strongly
1773 * normalized to the value-set 0..1 (i.e., the value is truncated
1774 * to the least-significant bit). See {@link #byte2bool(byte)} for
1775 * more details on conversion conventions.
1776 *
1777 * @param b the boolean to be converted to byte (and then normalized)
1778 * @return the result of the conversion
1779 */
1780 @ForceInline
1781 private byte bool2byte(boolean b) {
1782 return b ? (byte)1 : (byte)0;
1783 }
1784
1785 @ForceInline
1786 public final boolean compareAndSetBoolean(Object o, long offset,
1787 boolean expected,
1788 boolean x) {
1789 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1790 }
1791
1792 @ForceInline
1793 public final boolean compareAndExchangeBoolean(Object o, long offset,
1794 boolean expected,
1795 boolean x) {
1796 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1797 }
1798
1799 @ForceInline
1800 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1801 boolean expected,
1802 boolean x) {
1803 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1804 }
1805
1806 @ForceInline
1807 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1808 boolean expected,
1809 boolean x) {
1810 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1811 }
1812
1813 @ForceInline
1814 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1815 boolean expected,
1816 boolean x) {
1817 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1818 }
1819
1820 @ForceInline
1821 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1822 boolean expected,
1823 boolean x) {
1824 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1825 }
1826
1827 @ForceInline
1828 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1829 boolean expected,
1830 boolean x) {
1831 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1832 }
1833
1834 @ForceInline
1835 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1836 boolean expected,
1837 boolean x) {
1838 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1839 }
1840
1841 /**
1842 * Atomically updates Java variable to {@code x} if it is currently
1843 * holding {@code expected}.
1844 *
1845 * <p>This operation has memory semantics of a {@code volatile} read
1846 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1847 *
1848 * @return {@code true} if successful
1849 */
1850 @ForceInline
1851 public final boolean compareAndSetFloat(Object o, long offset,
1852 float expected,
1853 float x) {
1854 return compareAndSetInt(o, offset,
1855 Float.floatToRawIntBits(expected),
1856 Float.floatToRawIntBits(x));
1857 }
1858
1859 @ForceInline
1860 public final float compareAndExchangeFloat(Object o, long offset,
1861 float expected,
1862 float x) {
1863 int w = compareAndExchangeInt(o, offset,
1864 Float.floatToRawIntBits(expected),
1865 Float.floatToRawIntBits(x));
1866 return Float.intBitsToFloat(w);
1867 }
1868
1869 @ForceInline
1870 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1871 float expected,
1872 float x) {
1873 int w = compareAndExchangeIntAcquire(o, offset,
1874 Float.floatToRawIntBits(expected),
1875 Float.floatToRawIntBits(x));
1876 return Float.intBitsToFloat(w);
1877 }
1878
1879 @ForceInline
1880 public final float compareAndExchangeFloatRelease(Object o, long offset,
1881 float expected,
1882 float x) {
1883 int w = compareAndExchangeIntRelease(o, offset,
1884 Float.floatToRawIntBits(expected),
1885 Float.floatToRawIntBits(x));
1886 return Float.intBitsToFloat(w);
1887 }
1888
1889 @ForceInline
1890 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
1891 float expected,
1892 float x) {
1893 return weakCompareAndSetIntPlain(o, offset,
1894 Float.floatToRawIntBits(expected),
1895 Float.floatToRawIntBits(x));
1896 }
1897
1898 @ForceInline
1899 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
1900 float expected,
1901 float x) {
1902 return weakCompareAndSetIntAcquire(o, offset,
1903 Float.floatToRawIntBits(expected),
1904 Float.floatToRawIntBits(x));
1905 }
1906
1907 @ForceInline
1908 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
1909 float expected,
1910 float x) {
1911 return weakCompareAndSetIntRelease(o, offset,
1912 Float.floatToRawIntBits(expected),
1913 Float.floatToRawIntBits(x));
1914 }
1915
1916 @ForceInline
1917 public final boolean weakCompareAndSetFloat(Object o, long offset,
1918 float expected,
1919 float x) {
1920 return weakCompareAndSetInt(o, offset,
1921 Float.floatToRawIntBits(expected),
1922 Float.floatToRawIntBits(x));
1923 }
1924
1925 /**
1926 * Atomically updates Java variable to {@code x} if it is currently
1927 * holding {@code expected}.
1928 *
1929 * <p>This operation has memory semantics of a {@code volatile} read
1930 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1931 *
1932 * @return {@code true} if successful
1933 */
1934 @ForceInline
1935 public final boolean compareAndSetDouble(Object o, long offset,
1936 double expected,
1937 double x) {
1938 return compareAndSetLong(o, offset,
1939 Double.doubleToRawLongBits(expected),
1940 Double.doubleToRawLongBits(x));
1941 }
1942
1943 @ForceInline
1944 public final double compareAndExchangeDouble(Object o, long offset,
1945 double expected,
1946 double x) {
1947 long w = compareAndExchangeLong(o, offset,
1948 Double.doubleToRawLongBits(expected),
1949 Double.doubleToRawLongBits(x));
1950 return Double.longBitsToDouble(w);
1951 }
1952
1953 @ForceInline
1954 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
1955 double expected,
1956 double x) {
1957 long w = compareAndExchangeLongAcquire(o, offset,
1958 Double.doubleToRawLongBits(expected),
1959 Double.doubleToRawLongBits(x));
1960 return Double.longBitsToDouble(w);
1961 }
1962
1963 @ForceInline
1964 public final double compareAndExchangeDoubleRelease(Object o, long offset,
1965 double expected,
1966 double x) {
1967 long w = compareAndExchangeLongRelease(o, offset,
1968 Double.doubleToRawLongBits(expected),
1969 Double.doubleToRawLongBits(x));
1970 return Double.longBitsToDouble(w);
1971 }
1972
1973 @ForceInline
1974 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
1975 double expected,
1976 double x) {
1977 return weakCompareAndSetLongPlain(o, offset,
1978 Double.doubleToRawLongBits(expected),
1979 Double.doubleToRawLongBits(x));
1980 }
1981
1982 @ForceInline
1983 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
1984 double expected,
1985 double x) {
1986 return weakCompareAndSetLongAcquire(o, offset,
1987 Double.doubleToRawLongBits(expected),
1988 Double.doubleToRawLongBits(x));
1989 }
1990
1991 @ForceInline
1992 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
1993 double expected,
1994 double x) {
1995 return weakCompareAndSetLongRelease(o, offset,
1996 Double.doubleToRawLongBits(expected),
1997 Double.doubleToRawLongBits(x));
1998 }
1999
2000 @ForceInline
2001 public final boolean weakCompareAndSetDouble(Object o, long offset,
2002 double expected,
2003 double x) {
2004 return weakCompareAndSetLong(o, offset,
2005 Double.doubleToRawLongBits(expected),
2006 Double.doubleToRawLongBits(x));
2007 }
2008
2009 /**
2010 * Atomically updates Java variable to {@code x} if it is currently
2011 * holding {@code expected}.
2012 *
2013 * <p>This operation has memory semantics of a {@code volatile} read
2014 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2015 *
2016 * @return {@code true} if successful
2017 */
2018 @IntrinsicCandidate
2019 public final native boolean compareAndSetLong(Object o, long offset,
2020 long expected,
2021 long x);
2022
2023 @IntrinsicCandidate
2024 public final native long compareAndExchangeLong(Object o, long offset,
2025 long expected,
2026 long x);
2027
2028 @IntrinsicCandidate
2029 public final long compareAndExchangeLongAcquire(Object o, long offset,
2030 long expected,
2031 long x) {
2032 return compareAndExchangeLong(o, offset, expected, x);
2033 }
2034
2035 @IntrinsicCandidate
2036 public final long compareAndExchangeLongRelease(Object o, long offset,
2037 long expected,
2038 long x) {
2039 return compareAndExchangeLong(o, offset, expected, x);
2040 }
2041
2042 @IntrinsicCandidate
2043 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2044 long expected,
2045 long x) {
2046 return compareAndSetLong(o, offset, expected, x);
2047 }
2048
2049 @IntrinsicCandidate
2050 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2051 long expected,
2052 long x) {
2053 return compareAndSetLong(o, offset, expected, x);
2054 }
2055
2056 @IntrinsicCandidate
2057 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2058 long expected,
2059 long x) {
2060 return compareAndSetLong(o, offset, expected, x);
2061 }
2062
2063 @IntrinsicCandidate
2064 public final boolean weakCompareAndSetLong(Object o, long offset,
2065 long expected,
2066 long x) {
2067 return compareAndSetLong(o, offset, expected, x);
2068 }
2069
2070 /**
2071 * Fetches a reference value from a given Java variable, with volatile
2072 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2073 */
2074 @IntrinsicCandidate
2075 public native Object getReferenceVolatile(Object o, long offset);
2076
2077 /**
2078 * Stores a reference value into a given Java variable, with
2079 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2080 */
2081 @IntrinsicCandidate
2082 public native void putReferenceVolatile(Object o, long offset, Object x);
2083
2084 /** Volatile version of {@link #getInt(Object, long)} */
2085 @IntrinsicCandidate
2086 public native int getIntVolatile(Object o, long offset);
2087
2088 /** Volatile version of {@link #putInt(Object, long, int)} */
2089 @IntrinsicCandidate
2090 public native void putIntVolatile(Object o, long offset, int x);
2091
2092 /** Volatile version of {@link #getBoolean(Object, long)} */
2093 @IntrinsicCandidate
2094 public native boolean getBooleanVolatile(Object o, long offset);
2095
2096 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2097 @IntrinsicCandidate
2098 public native void putBooleanVolatile(Object o, long offset, boolean x);
2099
2100 /** Volatile version of {@link #getByte(Object, long)} */
2101 @IntrinsicCandidate
2102 public native byte getByteVolatile(Object o, long offset);
2103
2104 /** Volatile version of {@link #putByte(Object, long, byte)} */
2105 @IntrinsicCandidate
2106 public native void putByteVolatile(Object o, long offset, byte x);
2107
2108 /** Volatile version of {@link #getShort(Object, long)} */
2109 @IntrinsicCandidate
2110 public native short getShortVolatile(Object o, long offset);
2111
2112 /** Volatile version of {@link #putShort(Object, long, short)} */
2113 @IntrinsicCandidate
2114 public native void putShortVolatile(Object o, long offset, short x);
2115
2116 /** Volatile version of {@link #getChar(Object, long)} */
2117 @IntrinsicCandidate
2118 public native char getCharVolatile(Object o, long offset);
2119
2120 /** Volatile version of {@link #putChar(Object, long, char)} */
2121 @IntrinsicCandidate
2122 public native void putCharVolatile(Object o, long offset, char x);
2123
2124 /** Volatile version of {@link #getLong(Object, long)} */
2125 @IntrinsicCandidate
2126 public native long getLongVolatile(Object o, long offset);
2127
2128 /** Volatile version of {@link #putLong(Object, long, long)} */
2129 @IntrinsicCandidate
2130 public native void putLongVolatile(Object o, long offset, long x);
2131
2132 /** Volatile version of {@link #getFloat(Object, long)} */
2133 @IntrinsicCandidate
2134 public native float getFloatVolatile(Object o, long offset);
2135
2136 /** Volatile version of {@link #putFloat(Object, long, float)} */
2137 @IntrinsicCandidate
2138 public native void putFloatVolatile(Object o, long offset, float x);
2139
2140 /** Volatile version of {@link #getDouble(Object, long)} */
2141 @IntrinsicCandidate
2142 public native double getDoubleVolatile(Object o, long offset);
2143
2144 /** Volatile version of {@link #putDouble(Object, long, double)} */
2145 @IntrinsicCandidate
2146 public native void putDoubleVolatile(Object o, long offset, double x);
2147
2148
2149
2150 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2151 @IntrinsicCandidate
2152 public final Object getReferenceAcquire(Object o, long offset) {
2153 return getReferenceVolatile(o, offset);
2154 }
2155
2156 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2157 @IntrinsicCandidate
2158 public final boolean getBooleanAcquire(Object o, long offset) {
2159 return getBooleanVolatile(o, offset);
2160 }
2161
2162 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2163 @IntrinsicCandidate
2164 public final byte getByteAcquire(Object o, long offset) {
2165 return getByteVolatile(o, offset);
2166 }
2167
2168 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2169 @IntrinsicCandidate
2170 public final short getShortAcquire(Object o, long offset) {
2171 return getShortVolatile(o, offset);
2172 }
2173
2174 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2175 @IntrinsicCandidate
2176 public final char getCharAcquire(Object o, long offset) {
2177 return getCharVolatile(o, offset);
2178 }
2179
2180 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2181 @IntrinsicCandidate
2182 public final int getIntAcquire(Object o, long offset) {
2183 return getIntVolatile(o, offset);
2184 }
2185
2186 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2187 @IntrinsicCandidate
2188 public final float getFloatAcquire(Object o, long offset) {
2189 return getFloatVolatile(o, offset);
2190 }
2191
2192 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2193 @IntrinsicCandidate
2194 public final long getLongAcquire(Object o, long offset) {
2195 return getLongVolatile(o, offset);
2196 }
2197
2198 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2199 @IntrinsicCandidate
2200 public final double getDoubleAcquire(Object o, long offset) {
2201 return getDoubleVolatile(o, offset);
2202 }
2203
2204 /*
2205 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2206 * that do not guarantee immediate visibility of the store to
2207 * other threads. This method is generally only useful if the
2208 * underlying field is a Java volatile (or if an array cell, one
2209 * that is otherwise only accessed using volatile accesses).
2210 *
2211 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2212 */
2213
2214 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2215 @IntrinsicCandidate
2216 public final void putReferenceRelease(Object o, long offset, Object x) {
2217 putReferenceVolatile(o, offset, x);
2218 }
2219
2220 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2221 @IntrinsicCandidate
2222 public final void putBooleanRelease(Object o, long offset, boolean x) {
2223 putBooleanVolatile(o, offset, x);
2224 }
2225
2226 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2227 @IntrinsicCandidate
2228 public final void putByteRelease(Object o, long offset, byte x) {
2229 putByteVolatile(o, offset, x);
2230 }
2231
2232 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2233 @IntrinsicCandidate
2234 public final void putShortRelease(Object o, long offset, short x) {
2235 putShortVolatile(o, offset, x);
2236 }
2237
2238 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2239 @IntrinsicCandidate
2240 public final void putCharRelease(Object o, long offset, char x) {
2241 putCharVolatile(o, offset, x);
2242 }
2243
2244 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2245 @IntrinsicCandidate
2246 public final void putIntRelease(Object o, long offset, int x) {
2247 putIntVolatile(o, offset, x);
2248 }
2249
2250 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2251 @IntrinsicCandidate
2252 public final void putFloatRelease(Object o, long offset, float x) {
2253 putFloatVolatile(o, offset, x);
2254 }
2255
2256 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2257 @IntrinsicCandidate
2258 public final void putLongRelease(Object o, long offset, long x) {
2259 putLongVolatile(o, offset, x);
2260 }
2261
2262 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2263 @IntrinsicCandidate
2264 public final void putDoubleRelease(Object o, long offset, double x) {
2265 putDoubleVolatile(o, offset, x);
2266 }
2267
2268 // ------------------------------ Opaque --------------------------------------
2269
2270 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2271 @IntrinsicCandidate
2272 public final Object getReferenceOpaque(Object o, long offset) {
2273 return getReferenceVolatile(o, offset);
2274 }
2275
2276 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2277 @IntrinsicCandidate
2278 public final boolean getBooleanOpaque(Object o, long offset) {
2279 return getBooleanVolatile(o, offset);
2280 }
2281
2282 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2283 @IntrinsicCandidate
2284 public final byte getByteOpaque(Object o, long offset) {
2285 return getByteVolatile(o, offset);
2286 }
2287
2288 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2289 @IntrinsicCandidate
2290 public final short getShortOpaque(Object o, long offset) {
2291 return getShortVolatile(o, offset);
2292 }
2293
2294 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2295 @IntrinsicCandidate
2296 public final char getCharOpaque(Object o, long offset) {
2297 return getCharVolatile(o, offset);
2298 }
2299
2300 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2301 @IntrinsicCandidate
2302 public final int getIntOpaque(Object o, long offset) {
2303 return getIntVolatile(o, offset);
2304 }
2305
2306 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2307 @IntrinsicCandidate
2308 public final float getFloatOpaque(Object o, long offset) {
2309 return getFloatVolatile(o, offset);
2310 }
2311
2312 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2313 @IntrinsicCandidate
2314 public final long getLongOpaque(Object o, long offset) {
2315 return getLongVolatile(o, offset);
2316 }
2317
2318 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2319 @IntrinsicCandidate
2320 public final double getDoubleOpaque(Object o, long offset) {
2321 return getDoubleVolatile(o, offset);
2322 }
2323
2324 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2325 @IntrinsicCandidate
2326 public final void putReferenceOpaque(Object o, long offset, Object x) {
2327 putReferenceVolatile(o, offset, x);
2328 }
2329
2330 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2331 @IntrinsicCandidate
2332 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2333 putBooleanVolatile(o, offset, x);
2334 }
2335
2336 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2337 @IntrinsicCandidate
2338 public final void putByteOpaque(Object o, long offset, byte x) {
2339 putByteVolatile(o, offset, x);
2340 }
2341
2342 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2343 @IntrinsicCandidate
2344 public final void putShortOpaque(Object o, long offset, short x) {
2345 putShortVolatile(o, offset, x);
2346 }
2347
2348 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2349 @IntrinsicCandidate
2350 public final void putCharOpaque(Object o, long offset, char x) {
2351 putCharVolatile(o, offset, x);
2352 }
2353
2354 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2355 @IntrinsicCandidate
2356 public final void putIntOpaque(Object o, long offset, int x) {
2357 putIntVolatile(o, offset, x);
2358 }
2359
2360 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2361 @IntrinsicCandidate
2362 public final void putFloatOpaque(Object o, long offset, float x) {
2363 putFloatVolatile(o, offset, x);
2364 }
2365
2366 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2367 @IntrinsicCandidate
2368 public final void putLongOpaque(Object o, long offset, long x) {
2369 putLongVolatile(o, offset, x);
2370 }
2371
2372 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2373 @IntrinsicCandidate
2374 public final void putDoubleOpaque(Object o, long offset, double x) {
2375 putDoubleVolatile(o, offset, x);
2376 }
2377
2378 /**
2379 * Unblocks the given thread blocked on {@code park}, or, if it is
2380 * not blocked, causes the subsequent call to {@code park} not to
2381 * block. Note: this operation is "unsafe" solely because the
2382 * caller must somehow ensure that the thread has not been
2383 * destroyed. Nothing special is usually required to ensure this
2384 * when called from Java (in which there will ordinarily be a live
2385 * reference to the thread) but this is not nearly-automatically
2386 * so when calling from native code.
2387 *
2388 * @param thread the thread to unpark.
2389 */
2390 @IntrinsicCandidate
2391 public native void unpark(Object thread);
2392
2393 /**
2394 * Blocks current thread, returning when a balancing
2395 * {@code unpark} occurs, or a balancing {@code unpark} has
2396 * already occurred, or the thread is interrupted, or, if not
2397 * absolute and time is not zero, the given time nanoseconds have
2398 * elapsed, or if absolute, the given deadline in milliseconds
2399 * since Epoch has passed, or spuriously (i.e., returning for no
2400 * "reason"). Note: This operation is in the Unsafe class only
2401 * because {@code unpark} is, so it would be strange to place it
2402 * elsewhere.
2403 */
2404 @IntrinsicCandidate
2405 public native void park(boolean isAbsolute, long time);
2406
2407 /**
2408 * Gets the load average in the system run queue assigned
2409 * to the available processors averaged over various periods of time.
2410 * This method retrieves the given {@code nelem} samples and
2411 * assigns to the elements of the given {@code loadavg} array.
2412 * The system imposes a maximum of 3 samples, representing
2413 * averages over the last 1, 5, and 15 minutes, respectively.
2414 *
2415 * @param loadavg an array of double of size nelems
2416 * @param nelems the number of samples to be retrieved and
2417 * must be 1 to 3.
2418 *
2419 * @return the number of samples actually retrieved; or -1
2420 * if the load average is unobtainable.
2421 */
2422 public int getLoadAverage(double[] loadavg, int nelems) {
2423 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2424 throw new ArrayIndexOutOfBoundsException();
2425 }
2426
2427 return getLoadAverage0(loadavg, nelems);
2428 }
2429
2430 // The following contain CAS-based Java implementations used on
2431 // platforms not supporting native instructions
2432
2433 /**
2434 * Atomically adds the given value to the current value of a field
2435 * or array element within the given object {@code o}
2436 * at the given {@code offset}.
2437 *
2438 * @param o object/array to update the field/element in
2439 * @param offset field/element offset
2440 * @param delta the value to add
2441 * @return the previous value
2442 * @since 1.8
2443 */
2444 @IntrinsicCandidate
2445 public final int getAndAddInt(Object o, long offset, int delta) {
2446 int v;
2447 do {
2448 v = getIntVolatile(o, offset);
2449 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2450 return v;
2451 }
2452
2453 @ForceInline
2454 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2455 int v;
2456 do {
2457 v = getInt(o, offset);
2458 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2459 return v;
2460 }
2461
2462 @ForceInline
2463 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2464 int v;
2465 do {
2466 v = getIntAcquire(o, offset);
2467 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2468 return v;
2469 }
2470
2471 /**
2472 * Atomically adds the given value to the current value of a field
2473 * or array element within the given object {@code o}
2474 * at the given {@code offset}.
2475 *
2476 * @param o object/array to update the field/element in
2477 * @param offset field/element offset
2478 * @param delta the value to add
2479 * @return the previous value
2480 * @since 1.8
2481 */
2482 @IntrinsicCandidate
2483 public final long getAndAddLong(Object o, long offset, long delta) {
2484 long v;
2485 do {
2486 v = getLongVolatile(o, offset);
2487 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2488 return v;
2489 }
2490
2491 @ForceInline
2492 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2493 long v;
2494 do {
2495 v = getLong(o, offset);
2496 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2497 return v;
2498 }
2499
2500 @ForceInline
2501 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2502 long v;
2503 do {
2504 v = getLongAcquire(o, offset);
2505 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2506 return v;
2507 }
2508
2509 @IntrinsicCandidate
2510 public final byte getAndAddByte(Object o, long offset, byte delta) {
2511 byte v;
2512 do {
2513 v = getByteVolatile(o, offset);
2514 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2515 return v;
2516 }
2517
2518 @ForceInline
2519 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2520 byte v;
2521 do {
2522 v = getByte(o, offset);
2523 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2524 return v;
2525 }
2526
2527 @ForceInline
2528 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2529 byte v;
2530 do {
2531 v = getByteAcquire(o, offset);
2532 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2533 return v;
2534 }
2535
2536 @IntrinsicCandidate
2537 public final short getAndAddShort(Object o, long offset, short delta) {
2538 short v;
2539 do {
2540 v = getShortVolatile(o, offset);
2541 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2542 return v;
2543 }
2544
2545 @ForceInline
2546 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2547 short v;
2548 do {
2549 v = getShort(o, offset);
2550 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2551 return v;
2552 }
2553
2554 @ForceInline
2555 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2556 short v;
2557 do {
2558 v = getShortAcquire(o, offset);
2559 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2560 return v;
2561 }
2562
2563 @ForceInline
2564 public final char getAndAddChar(Object o, long offset, char delta) {
2565 return (char) getAndAddShort(o, offset, (short) delta);
2566 }
2567
2568 @ForceInline
2569 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2570 return (char) getAndAddShortRelease(o, offset, (short) delta);
2571 }
2572
2573 @ForceInline
2574 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2575 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2576 }
2577
2578 @ForceInline
2579 public final float getAndAddFloat(Object o, long offset, float delta) {
2580 int expectedBits;
2581 float v;
2582 do {
2583 // Load and CAS with the raw bits to avoid issues with NaNs and
2584 // possible bit conversion from signaling NaNs to quiet NaNs that
2585 // may result in the loop not terminating.
2586 expectedBits = getIntVolatile(o, offset);
2587 v = Float.intBitsToFloat(expectedBits);
2588 } while (!weakCompareAndSetInt(o, offset,
2589 expectedBits, Float.floatToRawIntBits(v + delta)));
2590 return v;
2591 }
2592
2593 @ForceInline
2594 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2595 int expectedBits;
2596 float v;
2597 do {
2598 // Load and CAS with the raw bits to avoid issues with NaNs and
2599 // possible bit conversion from signaling NaNs to quiet NaNs that
2600 // may result in the loop not terminating.
2601 expectedBits = getInt(o, offset);
2602 v = Float.intBitsToFloat(expectedBits);
2603 } while (!weakCompareAndSetIntRelease(o, offset,
2604 expectedBits, Float.floatToRawIntBits(v + delta)));
2605 return v;
2606 }
2607
2608 @ForceInline
2609 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2610 int expectedBits;
2611 float v;
2612 do {
2613 // Load and CAS with the raw bits to avoid issues with NaNs and
2614 // possible bit conversion from signaling NaNs to quiet NaNs that
2615 // may result in the loop not terminating.
2616 expectedBits = getIntAcquire(o, offset);
2617 v = Float.intBitsToFloat(expectedBits);
2618 } while (!weakCompareAndSetIntAcquire(o, offset,
2619 expectedBits, Float.floatToRawIntBits(v + delta)));
2620 return v;
2621 }
2622
2623 @ForceInline
2624 public final double getAndAddDouble(Object o, long offset, double delta) {
2625 long expectedBits;
2626 double v;
2627 do {
2628 // Load and CAS with the raw bits to avoid issues with NaNs and
2629 // possible bit conversion from signaling NaNs to quiet NaNs that
2630 // may result in the loop not terminating.
2631 expectedBits = getLongVolatile(o, offset);
2632 v = Double.longBitsToDouble(expectedBits);
2633 } while (!weakCompareAndSetLong(o, offset,
2634 expectedBits, Double.doubleToRawLongBits(v + delta)));
2635 return v;
2636 }
2637
2638 @ForceInline
2639 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2640 long expectedBits;
2641 double v;
2642 do {
2643 // Load and CAS with the raw bits to avoid issues with NaNs and
2644 // possible bit conversion from signaling NaNs to quiet NaNs that
2645 // may result in the loop not terminating.
2646 expectedBits = getLong(o, offset);
2647 v = Double.longBitsToDouble(expectedBits);
2648 } while (!weakCompareAndSetLongRelease(o, offset,
2649 expectedBits, Double.doubleToRawLongBits(v + delta)));
2650 return v;
2651 }
2652
2653 @ForceInline
2654 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2655 long expectedBits;
2656 double v;
2657 do {
2658 // Load and CAS with the raw bits to avoid issues with NaNs and
2659 // possible bit conversion from signaling NaNs to quiet NaNs that
2660 // may result in the loop not terminating.
2661 expectedBits = getLongAcquire(o, offset);
2662 v = Double.longBitsToDouble(expectedBits);
2663 } while (!weakCompareAndSetLongAcquire(o, offset,
2664 expectedBits, Double.doubleToRawLongBits(v + delta)));
2665 return v;
2666 }
2667
2668 /**
2669 * Atomically exchanges the given value with the current value of
2670 * a field or array element within the given object {@code o}
2671 * at the given {@code offset}.
2672 *
2673 * @param o object/array to update the field/element in
2674 * @param offset field/element offset
2675 * @param newValue new value
2676 * @return the previous value
2677 * @since 1.8
2678 */
2679 @IntrinsicCandidate
2680 public final int getAndSetInt(Object o, long offset, int newValue) {
2681 int v;
2682 do {
2683 v = getIntVolatile(o, offset);
2684 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2685 return v;
2686 }
2687
2688 @ForceInline
2689 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2690 int v;
2691 do {
2692 v = getInt(o, offset);
2693 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2694 return v;
2695 }
2696
2697 @ForceInline
2698 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2699 int v;
2700 do {
2701 v = getIntAcquire(o, offset);
2702 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2703 return v;
2704 }
2705
2706 /**
2707 * Atomically exchanges the given value with the current value of
2708 * a field or array element within the given object {@code o}
2709 * at the given {@code offset}.
2710 *
2711 * @param o object/array to update the field/element in
2712 * @param offset field/element offset
2713 * @param newValue new value
2714 * @return the previous value
2715 * @since 1.8
2716 */
2717 @IntrinsicCandidate
2718 public final long getAndSetLong(Object o, long offset, long newValue) {
2719 long v;
2720 do {
2721 v = getLongVolatile(o, offset);
2722 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2723 return v;
2724 }
2725
2726 @ForceInline
2727 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2728 long v;
2729 do {
2730 v = getLong(o, offset);
2731 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2732 return v;
2733 }
2734
2735 @ForceInline
2736 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2737 long v;
2738 do {
2739 v = getLongAcquire(o, offset);
2740 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2741 return v;
2742 }
2743
2744 /**
2745 * Atomically exchanges the given reference value with the current
2746 * reference value of a field or array element within the given
2747 * object {@code o} at the given {@code offset}.
2748 *
2749 * @param o object/array to update the field/element in
2750 * @param offset field/element offset
2751 * @param newValue new value
2752 * @return the previous value
2753 * @since 1.8
2754 */
2755 @IntrinsicCandidate
2756 public final Object getAndSetReference(Object o, long offset, Object newValue) {
2757 Object v;
2758 do {
2759 v = getReferenceVolatile(o, offset);
2760 } while (!weakCompareAndSetReference(o, offset, v, newValue));
2761 return v;
2762 }
2763
2764 @ForceInline
2765 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
2766 Object v;
2767 do {
2768 v = getReference(o, offset);
2769 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
2770 return v;
2771 }
2772
2773 @ForceInline
2774 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
2775 Object v;
2776 do {
2777 v = getReferenceAcquire(o, offset);
2778 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
2779 return v;
2780 }
2781
2782 @IntrinsicCandidate
2783 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2784 byte v;
2785 do {
2786 v = getByteVolatile(o, offset);
2787 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2788 return v;
2789 }
2790
2791 @ForceInline
2792 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2793 byte v;
2794 do {
2795 v = getByte(o, offset);
2796 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2797 return v;
2798 }
2799
2800 @ForceInline
2801 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2802 byte v;
2803 do {
2804 v = getByteAcquire(o, offset);
2805 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2806 return v;
2807 }
2808
2809 @ForceInline
2810 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2811 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2812 }
2813
2814 @ForceInline
2815 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2816 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2817 }
2818
2819 @ForceInline
2820 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2821 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2822 }
2823
2824 @IntrinsicCandidate
2825 public final short getAndSetShort(Object o, long offset, short newValue) {
2826 short v;
2827 do {
2828 v = getShortVolatile(o, offset);
2829 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2830 return v;
2831 }
2832
2833 @ForceInline
2834 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
2835 short v;
2836 do {
2837 v = getShort(o, offset);
2838 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
2839 return v;
2840 }
2841
2842 @ForceInline
2843 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
2844 short v;
2845 do {
2846 v = getShortAcquire(o, offset);
2847 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
2848 return v;
2849 }
2850
2851 @ForceInline
2852 public final char getAndSetChar(Object o, long offset, char newValue) {
2853 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2854 }
2855
2856 @ForceInline
2857 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
2858 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
2859 }
2860
2861 @ForceInline
2862 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
2863 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
2864 }
2865
2866 @ForceInline
2867 public final float getAndSetFloat(Object o, long offset, float newValue) {
2868 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
2869 return Float.intBitsToFloat(v);
2870 }
2871
2872 @ForceInline
2873 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
2874 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
2875 return Float.intBitsToFloat(v);
2876 }
2877
2878 @ForceInline
2879 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
2880 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
2881 return Float.intBitsToFloat(v);
2882 }
2883
2884 @ForceInline
2885 public final double getAndSetDouble(Object o, long offset, double newValue) {
2886 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
2887 return Double.longBitsToDouble(v);
2888 }
2889
2890 @ForceInline
2891 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
2892 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
2893 return Double.longBitsToDouble(v);
2894 }
2895
2896 @ForceInline
2897 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
2898 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
2899 return Double.longBitsToDouble(v);
2900 }
2901
2902
2903 // The following contain CAS-based Java implementations used on
2904 // platforms not supporting native instructions
2905
2906 @ForceInline
2907 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
2908 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
2909 }
2910
2911 @ForceInline
2912 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
2913 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
2914 }
2915
2916 @ForceInline
2917 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
2918 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
2919 }
2920
2921 @ForceInline
2922 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
2923 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
2924 }
2925
2926 @ForceInline
2927 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
2928 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
2929 }
2930
2931 @ForceInline
2932 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
2933 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
2934 }
2935
2936 @ForceInline
2937 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
2938 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
2939 }
2940
2941 @ForceInline
2942 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
2943 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
2944 }
2945
2946 @ForceInline
2947 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
2948 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
2949 }
2950
2951
2952 @ForceInline
2953 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
2954 byte current;
2955 do {
2956 current = getByteVolatile(o, offset);
2957 } while (!weakCompareAndSetByte(o, offset,
2958 current, (byte) (current | mask)));
2959 return current;
2960 }
2961
2962 @ForceInline
2963 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
2964 byte current;
2965 do {
2966 current = getByte(o, offset);
2967 } while (!weakCompareAndSetByteRelease(o, offset,
2968 current, (byte) (current | mask)));
2969 return current;
2970 }
2971
2972 @ForceInline
2973 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
2974 byte current;
2975 do {
2976 // Plain read, the value is a hint, the acquire CAS does the work
2977 current = getByte(o, offset);
2978 } while (!weakCompareAndSetByteAcquire(o, offset,
2979 current, (byte) (current | mask)));
2980 return current;
2981 }
2982
2983 @ForceInline
2984 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
2985 byte current;
2986 do {
2987 current = getByteVolatile(o, offset);
2988 } while (!weakCompareAndSetByte(o, offset,
2989 current, (byte) (current & mask)));
2990 return current;
2991 }
2992
2993 @ForceInline
2994 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
2995 byte current;
2996 do {
2997 current = getByte(o, offset);
2998 } while (!weakCompareAndSetByteRelease(o, offset,
2999 current, (byte) (current & mask)));
3000 return current;
3001 }
3002
3003 @ForceInline
3004 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3005 byte current;
3006 do {
3007 // Plain read, the value is a hint, the acquire CAS does the work
3008 current = getByte(o, offset);
3009 } while (!weakCompareAndSetByteAcquire(o, offset,
3010 current, (byte) (current & mask)));
3011 return current;
3012 }
3013
3014 @ForceInline
3015 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3016 byte current;
3017 do {
3018 current = getByteVolatile(o, offset);
3019 } while (!weakCompareAndSetByte(o, offset,
3020 current, (byte) (current ^ mask)));
3021 return current;
3022 }
3023
3024 @ForceInline
3025 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3026 byte current;
3027 do {
3028 current = getByte(o, offset);
3029 } while (!weakCompareAndSetByteRelease(o, offset,
3030 current, (byte) (current ^ mask)));
3031 return current;
3032 }
3033
3034 @ForceInline
3035 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3036 byte current;
3037 do {
3038 // Plain read, the value is a hint, the acquire CAS does the work
3039 current = getByte(o, offset);
3040 } while (!weakCompareAndSetByteAcquire(o, offset,
3041 current, (byte) (current ^ mask)));
3042 return current;
3043 }
3044
3045
3046 @ForceInline
3047 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3048 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3049 }
3050
3051 @ForceInline
3052 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3053 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3054 }
3055
3056 @ForceInline
3057 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3058 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3059 }
3060
3061 @ForceInline
3062 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3063 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3064 }
3065
3066 @ForceInline
3067 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3068 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3069 }
3070
3071 @ForceInline
3072 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3073 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3074 }
3075
3076 @ForceInline
3077 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3078 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3079 }
3080
3081 @ForceInline
3082 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3083 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3084 }
3085
3086 @ForceInline
3087 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3088 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3089 }
3090
3091
3092 @ForceInline
3093 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3094 short current;
3095 do {
3096 current = getShortVolatile(o, offset);
3097 } while (!weakCompareAndSetShort(o, offset,
3098 current, (short) (current | mask)));
3099 return current;
3100 }
3101
3102 @ForceInline
3103 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3104 short current;
3105 do {
3106 current = getShort(o, offset);
3107 } while (!weakCompareAndSetShortRelease(o, offset,
3108 current, (short) (current | mask)));
3109 return current;
3110 }
3111
3112 @ForceInline
3113 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3114 short current;
3115 do {
3116 // Plain read, the value is a hint, the acquire CAS does the work
3117 current = getShort(o, offset);
3118 } while (!weakCompareAndSetShortAcquire(o, offset,
3119 current, (short) (current | mask)));
3120 return current;
3121 }
3122
3123 @ForceInline
3124 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3125 short current;
3126 do {
3127 current = getShortVolatile(o, offset);
3128 } while (!weakCompareAndSetShort(o, offset,
3129 current, (short) (current & mask)));
3130 return current;
3131 }
3132
3133 @ForceInline
3134 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3135 short current;
3136 do {
3137 current = getShort(o, offset);
3138 } while (!weakCompareAndSetShortRelease(o, offset,
3139 current, (short) (current & mask)));
3140 return current;
3141 }
3142
3143 @ForceInline
3144 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3145 short current;
3146 do {
3147 // Plain read, the value is a hint, the acquire CAS does the work
3148 current = getShort(o, offset);
3149 } while (!weakCompareAndSetShortAcquire(o, offset,
3150 current, (short) (current & mask)));
3151 return current;
3152 }
3153
3154 @ForceInline
3155 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3156 short current;
3157 do {
3158 current = getShortVolatile(o, offset);
3159 } while (!weakCompareAndSetShort(o, offset,
3160 current, (short) (current ^ mask)));
3161 return current;
3162 }
3163
3164 @ForceInline
3165 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3166 short current;
3167 do {
3168 current = getShort(o, offset);
3169 } while (!weakCompareAndSetShortRelease(o, offset,
3170 current, (short) (current ^ mask)));
3171 return current;
3172 }
3173
3174 @ForceInline
3175 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3176 short current;
3177 do {
3178 // Plain read, the value is a hint, the acquire CAS does the work
3179 current = getShort(o, offset);
3180 } while (!weakCompareAndSetShortAcquire(o, offset,
3181 current, (short) (current ^ mask)));
3182 return current;
3183 }
3184
3185
3186 @ForceInline
3187 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3188 int current;
3189 do {
3190 current = getIntVolatile(o, offset);
3191 } while (!weakCompareAndSetInt(o, offset,
3192 current, current | mask));
3193 return current;
3194 }
3195
3196 @ForceInline
3197 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3198 int current;
3199 do {
3200 current = getInt(o, offset);
3201 } while (!weakCompareAndSetIntRelease(o, offset,
3202 current, current | mask));
3203 return current;
3204 }
3205
3206 @ForceInline
3207 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3208 int current;
3209 do {
3210 // Plain read, the value is a hint, the acquire CAS does the work
3211 current = getInt(o, offset);
3212 } while (!weakCompareAndSetIntAcquire(o, offset,
3213 current, current | mask));
3214 return current;
3215 }
3216
3217 /**
3218 * Atomically replaces the current value of a field or array element within
3219 * the given object with the result of bitwise AND between the current value
3220 * and mask.
3221 *
3222 * @param o object/array to update the field/element in
3223 * @param offset field/element offset
3224 * @param mask the mask value
3225 * @return the previous value
3226 * @since 9
3227 */
3228 @ForceInline
3229 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3230 int current;
3231 do {
3232 current = getIntVolatile(o, offset);
3233 } while (!weakCompareAndSetInt(o, offset,
3234 current, current & mask));
3235 return current;
3236 }
3237
3238 @ForceInline
3239 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3240 int current;
3241 do {
3242 current = getInt(o, offset);
3243 } while (!weakCompareAndSetIntRelease(o, offset,
3244 current, current & mask));
3245 return current;
3246 }
3247
3248 @ForceInline
3249 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3250 int current;
3251 do {
3252 // Plain read, the value is a hint, the acquire CAS does the work
3253 current = getInt(o, offset);
3254 } while (!weakCompareAndSetIntAcquire(o, offset,
3255 current, current & mask));
3256 return current;
3257 }
3258
3259 @ForceInline
3260 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3261 int current;
3262 do {
3263 current = getIntVolatile(o, offset);
3264 } while (!weakCompareAndSetInt(o, offset,
3265 current, current ^ mask));
3266 return current;
3267 }
3268
3269 @ForceInline
3270 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3271 int current;
3272 do {
3273 current = getInt(o, offset);
3274 } while (!weakCompareAndSetIntRelease(o, offset,
3275 current, current ^ mask));
3276 return current;
3277 }
3278
3279 @ForceInline
3280 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3281 int current;
3282 do {
3283 // Plain read, the value is a hint, the acquire CAS does the work
3284 current = getInt(o, offset);
3285 } while (!weakCompareAndSetIntAcquire(o, offset,
3286 current, current ^ mask));
3287 return current;
3288 }
3289
3290
3291 @ForceInline
3292 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3293 long current;
3294 do {
3295 current = getLongVolatile(o, offset);
3296 } while (!weakCompareAndSetLong(o, offset,
3297 current, current | mask));
3298 return current;
3299 }
3300
3301 @ForceInline
3302 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3303 long current;
3304 do {
3305 current = getLong(o, offset);
3306 } while (!weakCompareAndSetLongRelease(o, offset,
3307 current, current | mask));
3308 return current;
3309 }
3310
3311 @ForceInline
3312 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3313 long current;
3314 do {
3315 // Plain read, the value is a hint, the acquire CAS does the work
3316 current = getLong(o, offset);
3317 } while (!weakCompareAndSetLongAcquire(o, offset,
3318 current, current | mask));
3319 return current;
3320 }
3321
3322 @ForceInline
3323 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3324 long current;
3325 do {
3326 current = getLongVolatile(o, offset);
3327 } while (!weakCompareAndSetLong(o, offset,
3328 current, current & mask));
3329 return current;
3330 }
3331
3332 @ForceInline
3333 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3334 long current;
3335 do {
3336 current = getLong(o, offset);
3337 } while (!weakCompareAndSetLongRelease(o, offset,
3338 current, current & mask));
3339 return current;
3340 }
3341
3342 @ForceInline
3343 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3344 long current;
3345 do {
3346 // Plain read, the value is a hint, the acquire CAS does the work
3347 current = getLong(o, offset);
3348 } while (!weakCompareAndSetLongAcquire(o, offset,
3349 current, current & mask));
3350 return current;
3351 }
3352
3353 @ForceInline
3354 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3355 long current;
3356 do {
3357 current = getLongVolatile(o, offset);
3358 } while (!weakCompareAndSetLong(o, offset,
3359 current, current ^ mask));
3360 return current;
3361 }
3362
3363 @ForceInline
3364 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3365 long current;
3366 do {
3367 current = getLong(o, offset);
3368 } while (!weakCompareAndSetLongRelease(o, offset,
3369 current, current ^ mask));
3370 return current;
3371 }
3372
3373 @ForceInline
3374 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3375 long current;
3376 do {
3377 // Plain read, the value is a hint, the acquire CAS does the work
3378 current = getLong(o, offset);
3379 } while (!weakCompareAndSetLongAcquire(o, offset,
3380 current, current ^ mask));
3381 return current;
3382 }
3383
3384
3385
3386 /**
3387 * Ensures that loads before the fence will not be reordered with loads and
3388 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3389 *
3390 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3391 * (an "acquire fence").
3392 *
3393 * Provides a LoadLoad barrier followed by a LoadStore barrier.
3394 *
3395 * @since 1.8
3396 */
3397 @IntrinsicCandidate
3398 public final void loadFence() {
3399 // If loadFence intrinsic is not available, fall back to full fence.
3400 fullFence();
3401 }
3402
3403 /**
3404 * Ensures that loads and stores before the fence will not be reordered with
3405 * stores after the fence; a "StoreStore plus LoadStore barrier".
3406 *
3407 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3408 * (a "release fence").
3409 *
3410 * Provides a StoreStore barrier followed by a LoadStore barrier.
3411 *
3412 * @since 1.8
3413 */
3414 @IntrinsicCandidate
3415 public final void storeFence() {
3416 // If storeFence intrinsic is not available, fall back to full fence.
3417 fullFence();
3418 }
3419
3420 /**
3421 * Ensures that loads and stores before the fence will not be reordered
3422 * with loads and stores after the fence. Implies the effects of both
3423 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3424 * barrier.
3425 *
3426 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3427 * @since 1.8
3428 */
3429 @IntrinsicCandidate
3430 public native void fullFence();
3431
3432 /**
3433 * Ensures that loads before the fence will not be reordered with
3434 * loads after the fence.
3435 *
3436 * @implNote
3437 * This method is operationally equivalent to {@link #loadFence()}.
3438 *
3439 * @since 9
3440 */
3441 public final void loadLoadFence() {
3442 loadFence();
3443 }
3444
3445 /**
3446 * Ensures that stores before the fence will not be reordered with
3447 * stores after the fence.
3448 *
3449 * @since 9
3450 */
3451 @IntrinsicCandidate
3452 public final void storeStoreFence() {
3453 // If storeStoreFence intrinsic is not available, fall back to storeFence.
3454 storeFence();
3455 }
3456
3457 /**
3458 * Throws IllegalAccessError; for use by the VM for access control
3459 * error support.
3460 * @since 1.8
3461 */
3462 private static void throwIllegalAccessError() {
3463 throw new IllegalAccessError();
3464 }
3465
3466 /**
3467 * Throws NoSuchMethodError; for use by the VM for redefinition support.
3468 * @since 13
3469 */
3470 private static void throwNoSuchMethodError() {
3471 throw new NoSuchMethodError();
3472 }
3473
3474 /**
3475 * @return Returns true if the native byte ordering of this
3476 * platform is big-endian, false if it is little-endian.
3477 */
3478 public final boolean isBigEndian() { return BIG_ENDIAN; }
3479
3480 /**
3481 * @return Returns true if this platform is capable of performing
3482 * accesses at addresses which are not aligned for the type of the
3483 * primitive type being accessed, false otherwise.
3484 */
3485 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
3486
3487 /**
3488 * Fetches a value at some byte offset into a given Java object.
3489 * More specifically, fetches a value within the given object
3490 * <code>o</code> at the given offset, or (if <code>o</code> is
3491 * null) from the memory address whose numerical value is the
3492 * given offset. <p>
3493 *
3494 * The specification of this method is the same as {@link
3495 * #getLong(Object, long)} except that the offset does not need to
3496 * have been obtained from {@link #objectFieldOffset} on the
3497 * {@link java.lang.reflect.Field} of some Java field. The value
3498 * in memory is raw data, and need not correspond to any Java
3499 * variable. Unless <code>o</code> is null, the value accessed
3500 * must be entirely within the allocated object. The endianness
3501 * of the value in memory is the endianness of the native platform.
3502 *
3503 * <p> The read will be atomic with respect to the largest power
3504 * of two that divides the GCD of the offset and the storage size.
3505 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3506 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3507 * respectively. There are no other guarantees of atomicity.
3508 * <p>
3509 * 8-byte atomicity is only guaranteed on platforms on which
3510 * support atomic accesses to longs.
3511 *
3512 * @param o Java heap object in which the value resides, if any, else
3513 * null
3514 * @param offset The offset in bytes from the start of the object
3515 * @return the value fetched from the indicated object
3516 * @throws RuntimeException No defined exceptions are thrown, not even
3517 * {@link NullPointerException}
3518 * @since 9
3519 */
3520 @IntrinsicCandidate
3521 public final long getLongUnaligned(Object o, long offset) {
3522 if ((offset & 7) == 0) {
3523 return getLong(o, offset);
3524 } else if ((offset & 3) == 0) {
3525 return makeLong(getInt(o, offset),
3526 getInt(o, offset + 4));
3527 } else if ((offset & 1) == 0) {
3528 return makeLong(getShort(o, offset),
3529 getShort(o, offset + 2),
3530 getShort(o, offset + 4),
3531 getShort(o, offset + 6));
3532 } else {
3533 return makeLong(getByte(o, offset),
3534 getByte(o, offset + 1),
3535 getByte(o, offset + 2),
3536 getByte(o, offset + 3),
3537 getByte(o, offset + 4),
3538 getByte(o, offset + 5),
3539 getByte(o, offset + 6),
3540 getByte(o, offset + 7));
3541 }
3542 }
3543 /**
3544 * As {@link #getLongUnaligned(Object, long)} but with an
3545 * additional argument which specifies the endianness of the value
3546 * as stored in memory.
3547 *
3548 * @param o Java heap object in which the variable resides
3549 * @param offset The offset in bytes from the start of the object
3550 * @param bigEndian The endianness of the value
3551 * @return the value fetched from the indicated object
3552 * @since 9
3553 */
3554 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3555 return convEndian(bigEndian, getLongUnaligned(o, offset));
3556 }
3557
3558 /** @see #getLongUnaligned(Object, long) */
3559 @IntrinsicCandidate
3560 public final int getIntUnaligned(Object o, long offset) {
3561 if ((offset & 3) == 0) {
3562 return getInt(o, offset);
3563 } else if ((offset & 1) == 0) {
3564 return makeInt(getShort(o, offset),
3565 getShort(o, offset + 2));
3566 } else {
3567 return makeInt(getByte(o, offset),
3568 getByte(o, offset + 1),
3569 getByte(o, offset + 2),
3570 getByte(o, offset + 3));
3571 }
3572 }
3573 /** @see #getLongUnaligned(Object, long, boolean) */
3574 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3575 return convEndian(bigEndian, getIntUnaligned(o, offset));
3576 }
3577
3578 /** @see #getLongUnaligned(Object, long) */
3579 @IntrinsicCandidate
3580 public final short getShortUnaligned(Object o, long offset) {
3581 if ((offset & 1) == 0) {
3582 return getShort(o, offset);
3583 } else {
3584 return makeShort(getByte(o, offset),
3585 getByte(o, offset + 1));
3586 }
3587 }
3588 /** @see #getLongUnaligned(Object, long, boolean) */
3589 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3590 return convEndian(bigEndian, getShortUnaligned(o, offset));
3591 }
3592
3593 /** @see #getLongUnaligned(Object, long) */
3594 @IntrinsicCandidate
3595 public final char getCharUnaligned(Object o, long offset) {
3596 if ((offset & 1) == 0) {
3597 return getChar(o, offset);
3598 } else {
3599 return (char)makeShort(getByte(o, offset),
3600 getByte(o, offset + 1));
3601 }
3602 }
3603
3604 /** @see #getLongUnaligned(Object, long, boolean) */
3605 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3606 return convEndian(bigEndian, getCharUnaligned(o, offset));
3607 }
3608
3609 /**
3610 * Stores a value at some byte offset into a given Java object.
3611 * <p>
3612 * The specification of this method is the same as {@link
3613 * #getLong(Object, long)} except that the offset does not need to
3614 * have been obtained from {@link #objectFieldOffset} on the
3615 * {@link java.lang.reflect.Field} of some Java field. The value
3616 * in memory is raw data, and need not correspond to any Java
3617 * variable. The endianness of the value in memory is the
3618 * endianness of the native platform.
3619 * <p>
3620 * The write will be atomic with respect to the largest power of
3621 * two that divides the GCD of the offset and the storage size.
3622 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3623 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3624 * respectively. There are no other guarantees of atomicity.
3625 * <p>
3626 * 8-byte atomicity is only guaranteed on platforms on which
3627 * support atomic accesses to longs.
3628 *
3629 * @param o Java heap object in which the value resides, if any, else
3630 * null
3631 * @param offset The offset in bytes from the start of the object
3632 * @param x the value to store
3633 * @throws RuntimeException No defined exceptions are thrown, not even
3634 * {@link NullPointerException}
3635 * @since 9
3636 */
3637 @IntrinsicCandidate
3638 public final void putLongUnaligned(Object o, long offset, long x) {
3639 if ((offset & 7) == 0) {
3640 putLong(o, offset, x);
3641 } else if ((offset & 3) == 0) {
3642 putLongParts(o, offset,
3643 (int)(x >> 0),
3644 (int)(x >>> 32));
3645 } else if ((offset & 1) == 0) {
3646 putLongParts(o, offset,
3647 (short)(x >>> 0),
3648 (short)(x >>> 16),
3649 (short)(x >>> 32),
3650 (short)(x >>> 48));
3651 } else {
3652 putLongParts(o, offset,
3653 (byte)(x >>> 0),
3654 (byte)(x >>> 8),
3655 (byte)(x >>> 16),
3656 (byte)(x >>> 24),
3657 (byte)(x >>> 32),
3658 (byte)(x >>> 40),
3659 (byte)(x >>> 48),
3660 (byte)(x >>> 56));
3661 }
3662 }
3663
3664 /**
3665 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3666 * argument which specifies the endianness of the value as stored in memory.
3667 * @param o Java heap object in which the value resides
3668 * @param offset The offset in bytes from the start of the object
3669 * @param x the value to store
3670 * @param bigEndian The endianness of the value
3671 * @throws RuntimeException No defined exceptions are thrown, not even
3672 * {@link NullPointerException}
3673 * @since 9
3674 */
3675 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3676 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3677 }
3678
3679 /** @see #putLongUnaligned(Object, long, long) */
3680 @IntrinsicCandidate
3681 public final void putIntUnaligned(Object o, long offset, int x) {
3682 if ((offset & 3) == 0) {
3683 putInt(o, offset, x);
3684 } else if ((offset & 1) == 0) {
3685 putIntParts(o, offset,
3686 (short)(x >> 0),
3687 (short)(x >>> 16));
3688 } else {
3689 putIntParts(o, offset,
3690 (byte)(x >>> 0),
3691 (byte)(x >>> 8),
3692 (byte)(x >>> 16),
3693 (byte)(x >>> 24));
3694 }
3695 }
3696 /** @see #putLongUnaligned(Object, long, long, boolean) */
3697 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3698 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3699 }
3700
3701 /** @see #putLongUnaligned(Object, long, long) */
3702 @IntrinsicCandidate
3703 public final void putShortUnaligned(Object o, long offset, short x) {
3704 if ((offset & 1) == 0) {
3705 putShort(o, offset, x);
3706 } else {
3707 putShortParts(o, offset,
3708 (byte)(x >>> 0),
3709 (byte)(x >>> 8));
3710 }
3711 }
3712 /** @see #putLongUnaligned(Object, long, long, boolean) */
3713 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3714 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3715 }
3716
3717 /** @see #putLongUnaligned(Object, long, long) */
3718 @IntrinsicCandidate
3719 public final void putCharUnaligned(Object o, long offset, char x) {
3720 putShortUnaligned(o, offset, (short)x);
3721 }
3722 /** @see #putLongUnaligned(Object, long, long, boolean) */
3723 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3724 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3725 }
3726
3727 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
3728
3729 // These methods construct integers from bytes. The byte ordering
3730 // is the native endianness of this platform.
3731 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3732 return ((toUnsignedLong(i0) << pickPos(56, 0))
3733 | (toUnsignedLong(i1) << pickPos(56, 8))
3734 | (toUnsignedLong(i2) << pickPos(56, 16))
3735 | (toUnsignedLong(i3) << pickPos(56, 24))
3736 | (toUnsignedLong(i4) << pickPos(56, 32))
3737 | (toUnsignedLong(i5) << pickPos(56, 40))
3738 | (toUnsignedLong(i6) << pickPos(56, 48))
3739 | (toUnsignedLong(i7) << pickPos(56, 56)));
3740 }
3741 private static long makeLong(short i0, short i1, short i2, short i3) {
3742 return ((toUnsignedLong(i0) << pickPos(48, 0))
3743 | (toUnsignedLong(i1) << pickPos(48, 16))
3744 | (toUnsignedLong(i2) << pickPos(48, 32))
3745 | (toUnsignedLong(i3) << pickPos(48, 48)));
3746 }
3747 private static long makeLong(int i0, int i1) {
3748 return (toUnsignedLong(i0) << pickPos(32, 0))
3749 | (toUnsignedLong(i1) << pickPos(32, 32));
3750 }
3751 private static int makeInt(short i0, short i1) {
3752 return (toUnsignedInt(i0) << pickPos(16, 0))
3753 | (toUnsignedInt(i1) << pickPos(16, 16));
3754 }
3755 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3756 return ((toUnsignedInt(i0) << pickPos(24, 0))
3757 | (toUnsignedInt(i1) << pickPos(24, 8))
3758 | (toUnsignedInt(i2) << pickPos(24, 16))
3759 | (toUnsignedInt(i3) << pickPos(24, 24)));
3760 }
3761 private static short makeShort(byte i0, byte i1) {
3762 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3763 | (toUnsignedInt(i1) << pickPos(8, 8)));
3764 }
3765
3766 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
3767 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
3768 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
3769
3770 // These methods write integers to memory from smaller parts
3771 // provided by their caller. The ordering in which these parts
3772 // are written is the native endianness of this platform.
3773 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3774 putByte(o, offset + 0, pick(i0, i7));
3775 putByte(o, offset + 1, pick(i1, i6));
3776 putByte(o, offset + 2, pick(i2, i5));
3777 putByte(o, offset + 3, pick(i3, i4));
3778 putByte(o, offset + 4, pick(i4, i3));
3779 putByte(o, offset + 5, pick(i5, i2));
3780 putByte(o, offset + 6, pick(i6, i1));
3781 putByte(o, offset + 7, pick(i7, i0));
3782 }
3783 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3784 putShort(o, offset + 0, pick(i0, i3));
3785 putShort(o, offset + 2, pick(i1, i2));
3786 putShort(o, offset + 4, pick(i2, i1));
3787 putShort(o, offset + 6, pick(i3, i0));
3788 }
3789 private void putLongParts(Object o, long offset, int i0, int i1) {
3790 putInt(o, offset + 0, pick(i0, i1));
3791 putInt(o, offset + 4, pick(i1, i0));
3792 }
3793 private void putIntParts(Object o, long offset, short i0, short i1) {
3794 putShort(o, offset + 0, pick(i0, i1));
3795 putShort(o, offset + 2, pick(i1, i0));
3796 }
3797 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3798 putByte(o, offset + 0, pick(i0, i3));
3799 putByte(o, offset + 1, pick(i1, i2));
3800 putByte(o, offset + 2, pick(i2, i1));
3801 putByte(o, offset + 3, pick(i3, i0));
3802 }
3803 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3804 putByte(o, offset + 0, pick(i0, i1));
3805 putByte(o, offset + 1, pick(i1, i0));
3806 }
3807
3808 // Zero-extend an integer
3809 private static int toUnsignedInt(byte n) { return n & 0xff; }
3810 private static int toUnsignedInt(short n) { return n & 0xffff; }
3811 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3812 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3813 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3814
3815 // Maybe byte-reverse an integer
3816 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
3817 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
3818 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
3819 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
3820
3821
3822
3823 private native long allocateMemory0(long bytes);
3824 private native long reallocateMemory0(long address, long bytes);
3825 private native void freeMemory0(long address);
3826 private native void setMemory0(Object o, long offset, long bytes, byte value);
3827 @IntrinsicCandidate
3828 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3829 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3830 private native long objectFieldOffset0(Field f);
3831 private native long objectFieldOffset1(Class<?> c, String name);
3832 private native long staticFieldOffset0(Field f);
3833 private native Object staticFieldBase0(Field f);
3834 private native boolean shouldBeInitialized0(Class<?> c);
3835 private native void ensureClassInitialized0(Class<?> c);
3836 private native int arrayBaseOffset0(Class<?> arrayClass);
3837 private native int arrayIndexScale0(Class<?> arrayClass);
3838 private native int getLoadAverage0(double[] loadavg, int nelems);
3839
3840
3841 /**
3842 * Invokes the given direct byte buffer's cleaner, if any.
3843 *
3844 * @param directBuffer a direct byte buffer
3845 * @throws NullPointerException if {@code directBuffer} is null
3846 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
3847 * or is a {@link java.nio.Buffer#slice slice}, or is a
3848 * {@link java.nio.Buffer#duplicate duplicate}
3849 */
3850 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
3851 if (!directBuffer.isDirect())
3852 throw new IllegalArgumentException("buffer is non-direct");
3853
3854 DirectBuffer db = (DirectBuffer) directBuffer;
3855 if (db.attachment() != null)
3856 throw new IllegalArgumentException("duplicate or slice");
3857
3858 Cleaner cleaner = db.cleaner();
3859 if (cleaner != null) {
3860 cleaner.clean();
3861 }
3862 }
3863
3864 // The following deprecated methods are used by JSR 166.
3865
3866 @Deprecated(since="12", forRemoval=true)
3867 public final Object getObject(Object o, long offset) {
3868 return getReference(o, offset);
3869 }
3870 @Deprecated(since="12", forRemoval=true)
3871 public final Object getObjectVolatile(Object o, long offset) {
3872 return getReferenceVolatile(o, offset);
3873 }
3874 @Deprecated(since="12", forRemoval=true)
3875 public final Object getObjectAcquire(Object o, long offset) {
3876 return getReferenceAcquire(o, offset);
3877 }
3878 @Deprecated(since="12", forRemoval=true)
3879 public final Object getObjectOpaque(Object o, long offset) {
3880 return getReferenceOpaque(o, offset);
3881 }
3882
3883
3884 @Deprecated(since="12", forRemoval=true)
3885 public final void putObject(Object o, long offset, Object x) {
3886 putReference(o, offset, x);
3887 }
3888 @Deprecated(since="12", forRemoval=true)
3889 public final void putObjectVolatile(Object o, long offset, Object x) {
3890 putReferenceVolatile(o, offset, x);
3891 }
3892 @Deprecated(since="12", forRemoval=true)
3893 public final void putObjectOpaque(Object o, long offset, Object x) {
3894 putReferenceOpaque(o, offset, x);
3895 }
3896 @Deprecated(since="12", forRemoval=true)
3897 public final void putObjectRelease(Object o, long offset, Object x) {
3898 putReferenceRelease(o, offset, x);
3899 }
3900
3901
3902 @Deprecated(since="12", forRemoval=true)
3903 public final Object getAndSetObject(Object o, long offset, Object newValue) {
3904 return getAndSetReference(o, offset, newValue);
3905 }
3906 @Deprecated(since="12", forRemoval=true)
3907 public final Object getAndSetObjectAcquire(Object o, long offset, Object newValue) {
3908 return getAndSetReferenceAcquire(o, offset, newValue);
3909 }
3910 @Deprecated(since="12", forRemoval=true)
3911 public final Object getAndSetObjectRelease(Object o, long offset, Object newValue) {
3912 return getAndSetReferenceRelease(o, offset, newValue);
3913 }
3914
3915
3916 @Deprecated(since="12", forRemoval=true)
3917 public final boolean compareAndSetObject(Object o, long offset, Object expected, Object x) {
3918 return compareAndSetReference(o, offset, expected, x);
3919 }
3920 @Deprecated(since="12", forRemoval=true)
3921 public final Object compareAndExchangeObject(Object o, long offset, Object expected, Object x) {
3922 return compareAndExchangeReference(o, offset, expected, x);
3923 }
3924 @Deprecated(since="12", forRemoval=true)
3925 public final Object compareAndExchangeObjectAcquire(Object o, long offset, Object expected, Object x) {
3926 return compareAndExchangeReferenceAcquire(o, offset, expected, x);
3927 }
3928 @Deprecated(since="12", forRemoval=true)
3929 public final Object compareAndExchangeObjectRelease(Object o, long offset, Object expected, Object x) {
3930 return compareAndExchangeReferenceRelease(o, offset, expected, x);
3931 }
3932
3933
3934 @Deprecated(since="12", forRemoval=true)
3935 public final boolean weakCompareAndSetObject(Object o, long offset, Object expected, Object x) {
3936 return weakCompareAndSetReference(o, offset, expected, x);
3937 }
3938 @Deprecated(since="12", forRemoval=true)
3939 public final boolean weakCompareAndSetObjectAcquire(Object o, long offset, Object expected, Object x) {
3940 return weakCompareAndSetReferenceAcquire(o, offset, expected, x);
3941 }
3942 @Deprecated(since="12", forRemoval=true)
3943 public final boolean weakCompareAndSetObjectPlain(Object o, long offset, Object expected, Object x) {
3944 return weakCompareAndSetReferencePlain(o, offset, expected, x);
3945 }
3946 @Deprecated(since="12", forRemoval=true)
3947 public final boolean weakCompareAndSetObjectRelease(Object o, long offset, Object expected, Object x) {
3948 return weakCompareAndSetReferenceRelease(o, offset, expected, x);
3949 }
3950 }