1 /*
2 * Copyright (c) 2000, 2024, 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 be zero if and only if the
601 * requested size is zero. The resulting native pointer will be aligned for
602 * all value types. Dispose of this memory by calling {@link #freeMemory}
603 * or resize it with {@link #reallocateMemory}.
604 *
605 * <em>Note:</em> It is the responsibility of the caller to make
606 * sure arguments are checked before the methods are called. While
607 * some rudimentary checks are performed on the input, the checks
608 * are best effort and when performance is an overriding priority,
609 * as when methods of this class are optimized by the runtime
610 * compiler, some or all checks (if any) may be elided. Hence, the
611 * caller must not rely on the checks and corresponding
612 * exceptions!
613 *
614 * @throws RuntimeException if the size is negative or too large
615 * for the native size_t type
616 *
617 * @throws OutOfMemoryError if the allocation is refused by the system
618 *
619 * @see #getByte(long)
620 * @see #putByte(long, byte)
621 */
622 public long allocateMemory(long bytes) {
623 bytes = alignToHeapWordSize(bytes);
624
625 allocateMemoryChecks(bytes);
626
627 if (bytes == 0) {
628 return 0;
629 }
630
631 long p = allocateMemory0(bytes);
632 if (p == 0) {
633 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
634 }
635
636 return p;
637 }
638
639 /**
640 * Validate the arguments to allocateMemory
641 *
642 * @throws RuntimeException if the arguments are invalid
643 * (<em>Note:</em> after optimization, invalid inputs may
644 * go undetected, which will lead to unpredictable
645 * behavior)
646 */
647 private void allocateMemoryChecks(long bytes) {
648 checkSize(bytes);
649 }
650
651 /**
652 * Resizes a new block of native memory, to the given size in bytes. The
653 * contents of the new block past the size of the old block are
654 * uninitialized; they will generally be garbage. The resulting native
655 * pointer will be zero if and only if the requested size is zero. The
656 * resulting native pointer will be aligned for all value types. Dispose
657 * of this memory by calling {@link #freeMemory}, or resize it with {@link
658 * #reallocateMemory}. The address passed to this method may be null, in
659 * which case an allocation will be performed.
660 *
661 * <em>Note:</em> It is the responsibility of the caller to make
662 * sure arguments are checked before the methods are called. While
663 * some rudimentary checks are performed on the input, the checks
664 * are best effort and when performance is an overriding priority,
665 * as when methods of this class are optimized by the runtime
666 * compiler, some or all checks (if any) may be elided. Hence, the
667 * caller must not rely on the checks and corresponding
668 * exceptions!
669 *
670 * @throws RuntimeException if the size is negative or too large
671 * for the native size_t type
672 *
673 * @throws OutOfMemoryError if the allocation is refused by the system
674 *
675 * @see #allocateMemory
676 */
677 public long reallocateMemory(long address, long bytes) {
678 bytes = alignToHeapWordSize(bytes);
679
680 reallocateMemoryChecks(address, bytes);
681
682 if (bytes == 0) {
683 freeMemory(address);
684 return 0;
685 }
686
687 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
688 if (p == 0) {
689 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
690 }
691
692 return p;
693 }
694
695 /**
696 * Validate the arguments to reallocateMemory
697 *
698 * @throws RuntimeException if the arguments are invalid
699 * (<em>Note:</em> after optimization, invalid inputs may
700 * go undetected, which will lead to unpredictable
701 * behavior)
702 */
703 private void reallocateMemoryChecks(long address, long bytes) {
704 checkPointer(null, address);
705 checkSize(bytes);
706 }
707
708 /**
709 * Sets all bytes in a given block of memory to a fixed value
710 * (usually zero).
711 *
712 * <p>This method determines a block's base address by means of two parameters,
713 * and so it provides (in effect) a <em>double-register</em> addressing mode,
714 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
715 * the offset supplies an absolute base address.
716 *
717 * <p>The stores are in coherent (atomic) units of a size determined
718 * by the address and length parameters. If the effective address and
719 * length are all even modulo 8, the stores take place in 'long' units.
720 * If the effective address and length are (resp.) even modulo 4 or 2,
721 * the stores take place in units of 'int' or 'short'.
722 *
723 * <em>Note:</em> It is the responsibility of the caller to make
724 * sure arguments are checked before the methods are called. While
725 * some rudimentary checks are performed on the input, the checks
726 * are best effort and when performance is an overriding priority,
727 * as when methods of this class are optimized by the runtime
728 * compiler, some or all checks (if any) may be elided. Hence, the
729 * caller must not rely on the checks and corresponding
730 * exceptions!
731 *
732 * @throws RuntimeException if any of the arguments is invalid
733 *
734 * @since 1.7
735 */
736 public void setMemory(Object o, long offset, long bytes, byte value) {
737 setMemoryChecks(o, offset, bytes, value);
738
739 if (bytes == 0) {
740 return;
741 }
742
743 setMemory0(o, offset, bytes, value);
744 }
745
746 /**
747 * Sets all bytes in a given block of memory to a fixed value
748 * (usually zero). This provides a <em>single-register</em> addressing mode,
749 * as discussed in {@link #getInt(Object,long)}.
750 *
751 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
752 */
753 public void setMemory(long address, long bytes, byte value) {
754 setMemory(null, address, bytes, value);
755 }
756
757 /**
758 * Validate the arguments to setMemory
759 *
760 * @throws RuntimeException if the arguments are invalid
761 * (<em>Note:</em> after optimization, invalid inputs may
762 * go undetected, which will lead to unpredictable
763 * behavior)
764 */
765 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
766 checkPrimitivePointer(o, offset);
767 checkSize(bytes);
768 }
769
770 /**
771 * Sets all bytes in a given block of memory to a copy of another
772 * block.
773 *
774 * <p>This method determines each block's base address by means of two parameters,
775 * and so it provides (in effect) a <em>double-register</em> addressing mode,
776 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
777 * the offset supplies an absolute base address.
778 *
779 * <p>The transfers are in coherent (atomic) units of a size determined
780 * by the address and length parameters. If the effective addresses and
781 * length are all even modulo 8, the transfer takes place in 'long' units.
782 * If the effective addresses and length are (resp.) even modulo 4 or 2,
783 * the transfer takes place in units of 'int' or 'short'.
784 *
785 * <em>Note:</em> It is the responsibility of the caller to make
786 * sure arguments are checked before the methods are called. While
787 * some rudimentary checks are performed on the input, the checks
788 * are best effort and when performance is an overriding priority,
789 * as when methods of this class are optimized by the runtime
790 * compiler, some or all checks (if any) may be elided. Hence, the
791 * caller must not rely on the checks and corresponding
792 * exceptions!
793 *
794 * @throws RuntimeException if any of the arguments is invalid
795 *
796 * @since 1.7
797 */
798 public void copyMemory(Object srcBase, long srcOffset,
799 Object destBase, long destOffset,
800 long bytes) {
801 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
802
803 if (bytes == 0) {
804 return;
805 }
806
807 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
808 }
809
810 /**
811 * Sets all bytes in a given block of memory to a copy of another
812 * block. This provides a <em>single-register</em> addressing mode,
813 * as discussed in {@link #getInt(Object,long)}.
814 *
815 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
816 */
817 public void copyMemory(long srcAddress, long destAddress, long bytes) {
818 copyMemory(null, srcAddress, null, destAddress, bytes);
819 }
820
821 /**
822 * Validate the arguments to copyMemory
823 *
824 * @throws RuntimeException if any of the arguments is invalid
825 * (<em>Note:</em> after optimization, invalid inputs may
826 * go undetected, which will lead to unpredictable
827 * behavior)
828 */
829 private void copyMemoryChecks(Object srcBase, long srcOffset,
830 Object destBase, long destOffset,
831 long bytes) {
832 checkSize(bytes);
833 checkPrimitivePointer(srcBase, srcOffset);
834 checkPrimitivePointer(destBase, destOffset);
835 }
836
837 /**
838 * Copies all elements from one block of memory to another block,
839 * *unconditionally* byte swapping the elements on the fly.
840 *
841 * <p>This method determines each block's base address by means of two parameters,
842 * and so it provides (in effect) a <em>double-register</em> addressing mode,
843 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
844 * the offset supplies an absolute base address.
845 *
846 * <em>Note:</em> It is the responsibility of the caller to make
847 * sure arguments are checked before the methods are called. While
848 * some rudimentary checks are performed on the input, the checks
849 * are best effort and when performance is an overriding priority,
850 * as when methods of this class are optimized by the runtime
851 * compiler, some or all checks (if any) may be elided. Hence, the
852 * caller must not rely on the checks and corresponding
853 * exceptions!
854 *
855 * @throws RuntimeException if any of the arguments is invalid
856 *
857 * @since 9
858 */
859 public void copySwapMemory(Object srcBase, long srcOffset,
860 Object destBase, long destOffset,
861 long bytes, long elemSize) {
862 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
863
864 if (bytes == 0) {
865 return;
866 }
867
868 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
869 }
870
871 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
872 Object destBase, long destOffset,
873 long bytes, long elemSize) {
874 checkSize(bytes);
875
876 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
877 throw invalidInput();
878 }
879 if (bytes % elemSize != 0) {
880 throw invalidInput();
881 }
882
883 checkPrimitivePointer(srcBase, srcOffset);
884 checkPrimitivePointer(destBase, destOffset);
885 }
886
887 /**
888 * Copies all elements from one block of memory to another block, byte swapping the
889 * elements on the fly.
890 *
891 * This provides a <em>single-register</em> addressing mode, as
892 * discussed in {@link #getInt(Object,long)}.
893 *
894 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
895 */
896 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
897 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
898 }
899
900 /**
901 * Disposes of a block of native memory, as obtained from {@link
902 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
903 * this method may be null, in which case no action is taken.
904 *
905 * <em>Note:</em> It is the responsibility of the caller to make
906 * sure arguments are checked before the methods are called. While
907 * some rudimentary checks are performed on the input, the checks
908 * are best effort and when performance is an overriding priority,
909 * as when methods of this class are optimized by the runtime
910 * compiler, some or all checks (if any) may be elided. Hence, the
911 * caller must not rely on the checks and corresponding
912 * exceptions!
913 *
914 * @throws RuntimeException if any of the arguments is invalid
915 *
916 * @see #allocateMemory
917 */
918 public void freeMemory(long address) {
919 freeMemoryChecks(address);
920
921 if (address == 0) {
922 return;
923 }
924
925 freeMemory0(address);
926 }
927
928 /**
929 * Validate the arguments to freeMemory
930 *
931 * @throws RuntimeException if the arguments are invalid
932 * (<em>Note:</em> after optimization, invalid inputs may
933 * go undetected, which will lead to unpredictable
934 * behavior)
935 */
936 private void freeMemoryChecks(long address) {
937 checkPointer(null, address);
938 }
939
940 /**
941 * Ensure writeback of a specified virtual memory address range
942 * from cache to physical memory. All bytes in the address range
943 * are guaranteed to have been written back to physical memory on
944 * return from this call i.e. subsequently executed store
945 * instructions are guaranteed not to be visible before the
946 * writeback is completed.
947 *
948 * @param address
949 * the lowest byte address that must be guaranteed written
950 * back to memory. bytes at lower addresses may also be
951 * written back.
952 *
953 * @param length
954 * the length in bytes of the region starting at address
955 * that must be guaranteed written back to memory.
956 *
957 * @throws RuntimeException if memory writeback is not supported
958 * on the current hardware of if the arguments are invalid.
959 * (<em>Note:</em> after optimization, invalid inputs may
960 * go undetected, which will lead to unpredictable
961 * behavior)
962 *
963 * @since 14
964 */
965
966 public void writebackMemory(long address, long length) {
967 checkWritebackEnabled();
968 checkWritebackMemory(address, length);
969
970 // perform any required pre-writeback barrier
971 writebackPreSync0();
972
973 // write back one cache line at a time
974 long line = dataCacheLineAlignDown(address);
975 long end = address + length;
976 while (line < end) {
977 writeback0(line);
978 line += dataCacheLineFlushSize();
979 }
980
981 // perform any required post-writeback barrier
982 writebackPostSync0();
983 }
984
985 /**
986 * Validate the arguments to writebackMemory
987 *
988 * @throws RuntimeException if the arguments are invalid
989 * (<em>Note:</em> after optimization, invalid inputs may
990 * go undetected, which will lead to unpredictable
991 * behavior)
992 */
993 private void checkWritebackMemory(long address, long length) {
994 checkNativeAddress(address);
995 checkSize(length);
996 }
997
998 /**
999 * Validate that the current hardware supports memory writeback.
1000 * (<em>Note:</em> this is a belt and braces check. Clients are
1001 * expected to test whether writeback is enabled by calling
1002 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1003 * calling method {@link writeback #writeback} if it is disabled).
1004 *
1005 *
1006 * @throws RuntimeException if memory writeback is not supported
1007 */
1008 private void checkWritebackEnabled() {
1009 if (!isWritebackEnabled()) {
1010 throw new RuntimeException("writebackMemory not enabled!");
1011 }
1012 }
1013
1014 /**
1015 * force writeback of an individual cache line.
1016 *
1017 * @param address
1018 * the start address of the cache line to be written back
1019 */
1020 @IntrinsicCandidate
1021 private native void writeback0(long address);
1022
1023 /**
1024 * Serialize writeback operations relative to preceding memory writes.
1025 */
1026 @IntrinsicCandidate
1027 private native void writebackPreSync0();
1028
1029 /**
1030 * Serialize writeback operations relative to following memory writes.
1031 */
1032 @IntrinsicCandidate
1033 private native void writebackPostSync0();
1034
1035 //--- random queries
1036
1037 /**
1038 * This constant differs from all results that will ever be returned from
1039 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1040 * or {@link #arrayBaseOffset}.
1041 */
1042 public static final int INVALID_FIELD_OFFSET = -1;
1043
1044 /**
1045 * Reports the location of a given field in the storage allocation of its
1046 * class. Do not expect to perform any sort of arithmetic on this offset;
1047 * it is just a cookie which is passed to the unsafe heap memory accessors.
1048 *
1049 * <p>Any given field will always have the same offset and base, and no
1050 * two distinct fields of the same class will ever have the same offset
1051 * and base.
1052 *
1053 * <p>As of 1.4.1, offsets for fields are represented as long values,
1054 * although the Sun JVM does not use the most significant 32 bits.
1055 * However, JVM implementations which store static fields at absolute
1056 * addresses can use long offsets and null base pointers to express
1057 * the field locations in a form usable by {@link #getInt(Object,long)}.
1058 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1059 * must preserve all bits of static field offsets.
1060 * @see #getInt(Object, long)
1061 */
1062 public long objectFieldOffset(Field f) {
1063 if (f == null) {
1064 throw new NullPointerException();
1065 }
1066
1067 return objectFieldOffset0(f);
1068 }
1069
1070 /**
1071 * Reports the location of the field with a given name in the storage
1072 * allocation of its class.
1073 *
1074 * @throws NullPointerException if any parameter is {@code null}.
1075 * @throws InternalError if there is no field named {@code name} declared
1076 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1077 * would throw {@code java.lang.NoSuchFieldException}.
1078 *
1079 * @see #objectFieldOffset(Field)
1080 */
1081 public long objectFieldOffset(Class<?> c, String name) {
1082 if (c == null || name == null) {
1083 throw new NullPointerException();
1084 }
1085
1086 return objectFieldOffset1(c, name);
1087 }
1088
1089 /**
1090 * Reports the location of a given static field, in conjunction with {@link
1091 * #staticFieldBase}.
1092 * <p>Do not expect to perform any sort of arithmetic on this offset;
1093 * it is just a cookie which is passed to the unsafe heap memory accessors.
1094 *
1095 * <p>Any given field will always have the same offset, and no two distinct
1096 * fields of the same class will ever have the same offset.
1097 *
1098 * <p>As of 1.4.1, offsets for fields are represented as long values,
1099 * although the Sun JVM does not use the most significant 32 bits.
1100 * It is hard to imagine a JVM technology which needs more than
1101 * a few bits to encode an offset within a non-array object,
1102 * However, for consistency with other methods in this class,
1103 * this method reports its result as a long value.
1104 * @see #getInt(Object, long)
1105 */
1106 public long staticFieldOffset(Field f) {
1107 if (f == null) {
1108 throw new NullPointerException();
1109 }
1110
1111 return staticFieldOffset0(f);
1112 }
1113
1114 /**
1115 * Reports the location of a given static field, in conjunction with {@link
1116 * #staticFieldOffset}.
1117 * <p>Fetch the base "Object", if any, with which static fields of the
1118 * given class can be accessed via methods like {@link #getInt(Object,
1119 * long)}. This value may be null. This value may refer to an object
1120 * which is a "cookie", not guaranteed to be a real Object, and it should
1121 * not be used in any way except as argument to the get and put routines in
1122 * this class.
1123 */
1124 public Object staticFieldBase(Field f) {
1125 if (f == null) {
1126 throw new NullPointerException();
1127 }
1128
1129 return staticFieldBase0(f);
1130 }
1131
1132 /**
1133 * Detects if the given class may need to be initialized. This is often
1134 * needed in conjunction with obtaining the static field base of a
1135 * class.
1136 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1137 */
1138 public boolean shouldBeInitialized(Class<?> c) {
1139 if (c == null) {
1140 throw new NullPointerException();
1141 }
1142
1143 return shouldBeInitialized0(c);
1144 }
1145
1146 /**
1147 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1148 * This is often needed in conjunction with obtaining the static field base
1149 * of a class.
1150 *
1151 * The call returns when either class {@code c} is fully initialized or
1152 * class {@code c} is being initialized and the call is performed from
1153 * the initializing thread. In the latter case a subsequent call to
1154 * {@link #shouldBeInitialized} will return {@code true}.
1155 */
1156 public void ensureClassInitialized(Class<?> c) {
1157 if (c == null) {
1158 throw new NullPointerException();
1159 }
1160
1161 ensureClassInitialized0(c);
1162 }
1163
1164 /**
1165 * Reports the offset of the first element in the storage allocation of a
1166 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1167 * for the same class, you may use that scale factor, together with this
1168 * base offset, to form new offsets to access elements of arrays of the
1169 * given class.
1170 *
1171 * @see #getInt(Object, long)
1172 * @see #putInt(Object, long, int)
1173 */
1174 public int arrayBaseOffset(Class<?> arrayClass) {
1175 if (arrayClass == null) {
1176 throw new NullPointerException();
1177 }
1178
1179 return arrayBaseOffset0(arrayClass);
1180 }
1181
1182
1183 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1184 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1185 = theUnsafe.arrayBaseOffset(boolean[].class);
1186
1187 /** The value of {@code arrayBaseOffset(byte[].class)} */
1188 public static final int ARRAY_BYTE_BASE_OFFSET
1189 = theUnsafe.arrayBaseOffset(byte[].class);
1190
1191 /** The value of {@code arrayBaseOffset(short[].class)} */
1192 public static final int ARRAY_SHORT_BASE_OFFSET
1193 = theUnsafe.arrayBaseOffset(short[].class);
1194
1195 /** The value of {@code arrayBaseOffset(char[].class)} */
1196 public static final int ARRAY_CHAR_BASE_OFFSET
1197 = theUnsafe.arrayBaseOffset(char[].class);
1198
1199 /** The value of {@code arrayBaseOffset(int[].class)} */
1200 public static final int ARRAY_INT_BASE_OFFSET
1201 = theUnsafe.arrayBaseOffset(int[].class);
1202
1203 /** The value of {@code arrayBaseOffset(long[].class)} */
1204 public static final int ARRAY_LONG_BASE_OFFSET
1205 = theUnsafe.arrayBaseOffset(long[].class);
1206
1207 /** The value of {@code arrayBaseOffset(float[].class)} */
1208 public static final int ARRAY_FLOAT_BASE_OFFSET
1209 = theUnsafe.arrayBaseOffset(float[].class);
1210
1211 /** The value of {@code arrayBaseOffset(double[].class)} */
1212 public static final int ARRAY_DOUBLE_BASE_OFFSET
1213 = theUnsafe.arrayBaseOffset(double[].class);
1214
1215 /** The value of {@code arrayBaseOffset(Object[].class)} */
1216 public static final int ARRAY_OBJECT_BASE_OFFSET
1217 = theUnsafe.arrayBaseOffset(Object[].class);
1218
1219 /**
1220 * Reports the scale factor for addressing elements in the storage
1221 * allocation of a given array class. However, arrays of "narrow" types
1222 * will generally not work properly with accessors like {@link
1223 * #getByte(Object, long)}, so the scale factor for such classes is reported
1224 * as zero.
1225 *
1226 * @see #arrayBaseOffset
1227 * @see #getInt(Object, long)
1228 * @see #putInt(Object, long, int)
1229 */
1230 public int arrayIndexScale(Class<?> arrayClass) {
1231 if (arrayClass == null) {
1232 throw new NullPointerException();
1233 }
1234
1235 return arrayIndexScale0(arrayClass);
1236 }
1237
1238
1239 /** The value of {@code arrayIndexScale(boolean[].class)} */
1240 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1241 = theUnsafe.arrayIndexScale(boolean[].class);
1242
1243 /** The value of {@code arrayIndexScale(byte[].class)} */
1244 public static final int ARRAY_BYTE_INDEX_SCALE
1245 = theUnsafe.arrayIndexScale(byte[].class);
1246
1247 /** The value of {@code arrayIndexScale(short[].class)} */
1248 public static final int ARRAY_SHORT_INDEX_SCALE
1249 = theUnsafe.arrayIndexScale(short[].class);
1250
1251 /** The value of {@code arrayIndexScale(char[].class)} */
1252 public static final int ARRAY_CHAR_INDEX_SCALE
1253 = theUnsafe.arrayIndexScale(char[].class);
1254
1255 /** The value of {@code arrayIndexScale(int[].class)} */
1256 public static final int ARRAY_INT_INDEX_SCALE
1257 = theUnsafe.arrayIndexScale(int[].class);
1258
1259 /** The value of {@code arrayIndexScale(long[].class)} */
1260 public static final int ARRAY_LONG_INDEX_SCALE
1261 = theUnsafe.arrayIndexScale(long[].class);
1262
1263 /** The value of {@code arrayIndexScale(float[].class)} */
1264 public static final int ARRAY_FLOAT_INDEX_SCALE
1265 = theUnsafe.arrayIndexScale(float[].class);
1266
1267 /** The value of {@code arrayIndexScale(double[].class)} */
1268 public static final int ARRAY_DOUBLE_INDEX_SCALE
1269 = theUnsafe.arrayIndexScale(double[].class);
1270
1271 /** The value of {@code arrayIndexScale(Object[].class)} */
1272 public static final int ARRAY_OBJECT_INDEX_SCALE
1273 = theUnsafe.arrayIndexScale(Object[].class);
1274
1275 /**
1276 * Reports the size in bytes of a native pointer, as stored via {@link
1277 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1278 * other primitive types (as stored in native memory blocks) is determined
1279 * fully by their information content.
1280 */
1281 public int addressSize() {
1282 return ADDRESS_SIZE;
1283 }
1284
1285 /** The value of {@code addressSize()} */
1286 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1287
1288 /**
1289 * Reports the size in bytes of a native memory page (whatever that is).
1290 * This value will always be a power of two.
1291 */
1292 public int pageSize() { return PAGE_SIZE; }
1293
1294 /**
1295 * Reports the size in bytes of a data cache line written back by
1296 * the hardware cache line flush operation available to the JVM or
1297 * 0 if data cache line flushing is not enabled.
1298 */
1299 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1300
1301 /**
1302 * Rounds down address to a data cache line boundary as
1303 * determined by {@link #dataCacheLineFlushSize}
1304 * @return the rounded down address
1305 */
1306 public long dataCacheLineAlignDown(long address) {
1307 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1308 }
1309
1310 /**
1311 * Returns true if data cache line writeback
1312 */
1313 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1314
1315 //--- random trusted operations from JNI:
1316
1317 /**
1318 * Tells the VM to define a class, without security checks. By default, the
1319 * class loader and protection domain come from the caller's class.
1320 */
1321 public Class<?> defineClass(String name, byte[] b, int off, int len,
1322 ClassLoader loader,
1323 ProtectionDomain protectionDomain) {
1324 if (b == null) {
1325 throw new NullPointerException();
1326 }
1327 if (len < 0) {
1328 throw new ArrayIndexOutOfBoundsException();
1329 }
1330
1331 return defineClass0(name, b, off, len, loader, protectionDomain);
1332 }
1333
1334 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1335 ClassLoader loader,
1336 ProtectionDomain protectionDomain);
1337
1338 /**
1339 * Allocates an instance but does not run any constructor.
1340 * Initializes the class if it has not yet been.
1341 */
1342 @IntrinsicCandidate
1343 public native Object allocateInstance(Class<?> cls)
1344 throws InstantiationException;
1345
1346 /**
1347 * Allocates an array of a given type, but does not do zeroing.
1348 * <p>
1349 * This method should only be used in the very rare cases where a high-performance code
1350 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1351 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1352 * <p>
1353 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1354 * before allowing untrusted code, or code in other threads, to observe the reference
1355 * to the newly allocated array. In addition, the publication of the array reference must be
1356 * safe according to the Java Memory Model requirements.
1357 * <p>
1358 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1359 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1360 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1361 * or issuing a {@link #storeFence} before publishing the reference.
1362 * <p>
1363 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1364 * elements that could break heap integrity.
1365 *
1366 * @param componentType array component type to allocate
1367 * @param length array size to allocate
1368 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1369 * or the length is negative
1370 */
1371 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1372 if (componentType == null) {
1373 throw new IllegalArgumentException("Component type is null");
1374 }
1375 if (!componentType.isPrimitive()) {
1376 throw new IllegalArgumentException("Component type is not primitive");
1377 }
1378 if (length < 0) {
1379 throw new IllegalArgumentException("Negative length");
1380 }
1381 return allocateUninitializedArray0(componentType, length);
1382 }
1383
1384 @IntrinsicCandidate
1385 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1386 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1387 // return the zeroed arrays.
1388 if (componentType == byte.class) return new byte[length];
1389 if (componentType == boolean.class) return new boolean[length];
1390 if (componentType == short.class) return new short[length];
1391 if (componentType == char.class) return new char[length];
1392 if (componentType == int.class) return new int[length];
1393 if (componentType == float.class) return new float[length];
1394 if (componentType == long.class) return new long[length];
1395 if (componentType == double.class) return new double[length];
1396 return null;
1397 }
1398
1399 /** Throws the exception without telling the verifier. */
1400 public native void throwException(Throwable ee);
1401
1402 /**
1403 * Atomically updates Java variable to {@code x} if it is currently
1404 * holding {@code expected}.
1405 *
1406 * <p>This operation has memory semantics of a {@code volatile} read
1407 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1408 *
1409 * @return {@code true} if successful
1410 */
1411 @IntrinsicCandidate
1412 public final native boolean compareAndSetReference(Object o, long offset,
1413 Object expected,
1414 Object x);
1415
1416 @IntrinsicCandidate
1417 public final native Object compareAndExchangeReference(Object o, long offset,
1418 Object expected,
1419 Object x);
1420
1421 @IntrinsicCandidate
1422 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1423 Object expected,
1424 Object x) {
1425 return compareAndExchangeReference(o, offset, expected, x);
1426 }
1427
1428 @IntrinsicCandidate
1429 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1430 Object expected,
1431 Object x) {
1432 return compareAndExchangeReference(o, offset, expected, x);
1433 }
1434
1435 @IntrinsicCandidate
1436 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1437 Object expected,
1438 Object x) {
1439 return compareAndSetReference(o, offset, expected, x);
1440 }
1441
1442 @IntrinsicCandidate
1443 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1444 Object expected,
1445 Object x) {
1446 return compareAndSetReference(o, offset, expected, x);
1447 }
1448
1449 @IntrinsicCandidate
1450 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1451 Object expected,
1452 Object x) {
1453 return compareAndSetReference(o, offset, expected, x);
1454 }
1455
1456 @IntrinsicCandidate
1457 public final boolean weakCompareAndSetReference(Object o, long offset,
1458 Object expected,
1459 Object x) {
1460 return compareAndSetReference(o, offset, expected, x);
1461 }
1462
1463 /**
1464 * Atomically updates Java variable to {@code x} if it is currently
1465 * holding {@code expected}.
1466 *
1467 * <p>This operation has memory semantics of a {@code volatile} read
1468 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1469 *
1470 * @return {@code true} if successful
1471 */
1472 @IntrinsicCandidate
1473 public final native boolean compareAndSetInt(Object o, long offset,
1474 int expected,
1475 int x);
1476
1477 @IntrinsicCandidate
1478 public final native int compareAndExchangeInt(Object o, long offset,
1479 int expected,
1480 int x);
1481
1482 @IntrinsicCandidate
1483 public final int compareAndExchangeIntAcquire(Object o, long offset,
1484 int expected,
1485 int x) {
1486 return compareAndExchangeInt(o, offset, expected, x);
1487 }
1488
1489 @IntrinsicCandidate
1490 public final int compareAndExchangeIntRelease(Object o, long offset,
1491 int expected,
1492 int x) {
1493 return compareAndExchangeInt(o, offset, expected, x);
1494 }
1495
1496 @IntrinsicCandidate
1497 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1498 int expected,
1499 int x) {
1500 return compareAndSetInt(o, offset, expected, x);
1501 }
1502
1503 @IntrinsicCandidate
1504 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1505 int expected,
1506 int x) {
1507 return compareAndSetInt(o, offset, expected, x);
1508 }
1509
1510 @IntrinsicCandidate
1511 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1512 int expected,
1513 int x) {
1514 return compareAndSetInt(o, offset, expected, x);
1515 }
1516
1517 @IntrinsicCandidate
1518 public final boolean weakCompareAndSetInt(Object o, long offset,
1519 int expected,
1520 int x) {
1521 return compareAndSetInt(o, offset, expected, x);
1522 }
1523
1524 @IntrinsicCandidate
1525 public final byte compareAndExchangeByte(Object o, long offset,
1526 byte expected,
1527 byte x) {
1528 long wordOffset = offset & ~3;
1529 int shift = (int) (offset & 3) << 3;
1530 if (BIG_ENDIAN) {
1531 shift = 24 - shift;
1532 }
1533 int mask = 0xFF << shift;
1534 int maskedExpected = (expected & 0xFF) << shift;
1535 int maskedX = (x & 0xFF) << shift;
1536 int fullWord;
1537 do {
1538 fullWord = getIntVolatile(o, wordOffset);
1539 if ((fullWord & mask) != maskedExpected)
1540 return (byte) ((fullWord & mask) >> shift);
1541 } while (!weakCompareAndSetInt(o, wordOffset,
1542 fullWord, (fullWord & ~mask) | maskedX));
1543 return expected;
1544 }
1545
1546 @IntrinsicCandidate
1547 public final boolean compareAndSetByte(Object o, long offset,
1548 byte expected,
1549 byte x) {
1550 return compareAndExchangeByte(o, offset, expected, x) == expected;
1551 }
1552
1553 @IntrinsicCandidate
1554 public final boolean weakCompareAndSetByte(Object o, long offset,
1555 byte expected,
1556 byte x) {
1557 return compareAndSetByte(o, offset, expected, x);
1558 }
1559
1560 @IntrinsicCandidate
1561 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1562 byte expected,
1563 byte x) {
1564 return weakCompareAndSetByte(o, offset, expected, x);
1565 }
1566
1567 @IntrinsicCandidate
1568 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1569 byte expected,
1570 byte x) {
1571 return weakCompareAndSetByte(o, offset, expected, x);
1572 }
1573
1574 @IntrinsicCandidate
1575 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1576 byte expected,
1577 byte x) {
1578 return weakCompareAndSetByte(o, offset, expected, x);
1579 }
1580
1581 @IntrinsicCandidate
1582 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1583 byte expected,
1584 byte x) {
1585 return compareAndExchangeByte(o, offset, expected, x);
1586 }
1587
1588 @IntrinsicCandidate
1589 public final byte compareAndExchangeByteRelease(Object o, long offset,
1590 byte expected,
1591 byte x) {
1592 return compareAndExchangeByte(o, offset, expected, x);
1593 }
1594
1595 @IntrinsicCandidate
1596 public final short compareAndExchangeShort(Object o, long offset,
1597 short expected,
1598 short x) {
1599 if ((offset & 3) == 3) {
1600 throw new IllegalArgumentException("Update spans the word, not supported");
1601 }
1602 long wordOffset = offset & ~3;
1603 int shift = (int) (offset & 3) << 3;
1604 if (BIG_ENDIAN) {
1605 shift = 16 - shift;
1606 }
1607 int mask = 0xFFFF << shift;
1608 int maskedExpected = (expected & 0xFFFF) << shift;
1609 int maskedX = (x & 0xFFFF) << shift;
1610 int fullWord;
1611 do {
1612 fullWord = getIntVolatile(o, wordOffset);
1613 if ((fullWord & mask) != maskedExpected) {
1614 return (short) ((fullWord & mask) >> shift);
1615 }
1616 } while (!weakCompareAndSetInt(o, wordOffset,
1617 fullWord, (fullWord & ~mask) | maskedX));
1618 return expected;
1619 }
1620
1621 @IntrinsicCandidate
1622 public final boolean compareAndSetShort(Object o, long offset,
1623 short expected,
1624 short x) {
1625 return compareAndExchangeShort(o, offset, expected, x) == expected;
1626 }
1627
1628 @IntrinsicCandidate
1629 public final boolean weakCompareAndSetShort(Object o, long offset,
1630 short expected,
1631 short x) {
1632 return compareAndSetShort(o, offset, expected, x);
1633 }
1634
1635 @IntrinsicCandidate
1636 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1637 short expected,
1638 short x) {
1639 return weakCompareAndSetShort(o, offset, expected, x);
1640 }
1641
1642 @IntrinsicCandidate
1643 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1644 short expected,
1645 short x) {
1646 return weakCompareAndSetShort(o, offset, expected, x);
1647 }
1648
1649 @IntrinsicCandidate
1650 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1651 short expected,
1652 short x) {
1653 return weakCompareAndSetShort(o, offset, expected, x);
1654 }
1655
1656
1657 @IntrinsicCandidate
1658 public final short compareAndExchangeShortAcquire(Object o, long offset,
1659 short expected,
1660 short x) {
1661 return compareAndExchangeShort(o, offset, expected, x);
1662 }
1663
1664 @IntrinsicCandidate
1665 public final short compareAndExchangeShortRelease(Object o, long offset,
1666 short expected,
1667 short x) {
1668 return compareAndExchangeShort(o, offset, expected, x);
1669 }
1670
1671 @ForceInline
1672 private char s2c(short s) {
1673 return (char) s;
1674 }
1675
1676 @ForceInline
1677 private short c2s(char s) {
1678 return (short) s;
1679 }
1680
1681 @ForceInline
1682 public final boolean compareAndSetChar(Object o, long offset,
1683 char expected,
1684 char x) {
1685 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1686 }
1687
1688 @ForceInline
1689 public final char compareAndExchangeChar(Object o, long offset,
1690 char expected,
1691 char x) {
1692 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1693 }
1694
1695 @ForceInline
1696 public final char compareAndExchangeCharAcquire(Object o, long offset,
1697 char expected,
1698 char x) {
1699 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1700 }
1701
1702 @ForceInline
1703 public final char compareAndExchangeCharRelease(Object o, long offset,
1704 char expected,
1705 char x) {
1706 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1707 }
1708
1709 @ForceInline
1710 public final boolean weakCompareAndSetChar(Object o, long offset,
1711 char expected,
1712 char x) {
1713 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1714 }
1715
1716 @ForceInline
1717 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1718 char expected,
1719 char x) {
1720 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1721 }
1722
1723 @ForceInline
1724 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1725 char expected,
1726 char x) {
1727 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1728 }
1729
1730 @ForceInline
1731 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1732 char expected,
1733 char x) {
1734 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1735 }
1736
1737 /**
1738 * The JVM converts integral values to boolean values using two
1739 * different conventions, byte testing against zero and truncation
1740 * to least-significant bit.
1741 *
1742 * <p>The JNI documents specify that, at least for returning
1743 * values from native methods, a Java boolean value is converted
1744 * to the value-set 0..1 by first truncating to a byte (0..255 or
1745 * maybe -128..127) and then testing against zero. Thus, Java
1746 * booleans in non-Java data structures are by convention
1747 * represented as 8-bit containers containing either zero (for
1748 * false) or any non-zero value (for true).
1749 *
1750 * <p>Java booleans in the heap are also stored in bytes, but are
1751 * strongly normalized to the value-set 0..1 (i.e., they are
1752 * truncated to the least-significant bit).
1753 *
1754 * <p>The main reason for having different conventions for
1755 * conversion is performance: Truncation to the least-significant
1756 * bit can be usually implemented with fewer (machine)
1757 * instructions than byte testing against zero.
1758 *
1759 * <p>A number of Unsafe methods load boolean values from the heap
1760 * as bytes. Unsafe converts those values according to the JNI
1761 * rules (i.e, using the "testing against zero" convention). The
1762 * method {@code byte2bool} implements that conversion.
1763 *
1764 * @param b the byte to be converted to boolean
1765 * @return the result of the conversion
1766 */
1767 @ForceInline
1768 private boolean byte2bool(byte b) {
1769 return b != 0;
1770 }
1771
1772 /**
1773 * Convert a boolean value to a byte. The return value is strongly
1774 * normalized to the value-set 0..1 (i.e., the value is truncated
1775 * to the least-significant bit). See {@link #byte2bool(byte)} for
1776 * more details on conversion conventions.
1777 *
1778 * @param b the boolean to be converted to byte (and then normalized)
1779 * @return the result of the conversion
1780 */
1781 @ForceInline
1782 private byte bool2byte(boolean b) {
1783 return b ? (byte)1 : (byte)0;
1784 }
1785
1786 @ForceInline
1787 public final boolean compareAndSetBoolean(Object o, long offset,
1788 boolean expected,
1789 boolean x) {
1790 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1791 }
1792
1793 @ForceInline
1794 public final boolean compareAndExchangeBoolean(Object o, long offset,
1795 boolean expected,
1796 boolean x) {
1797 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1798 }
1799
1800 @ForceInline
1801 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1802 boolean expected,
1803 boolean x) {
1804 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1805 }
1806
1807 @ForceInline
1808 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1809 boolean expected,
1810 boolean x) {
1811 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1812 }
1813
1814 @ForceInline
1815 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1816 boolean expected,
1817 boolean x) {
1818 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1819 }
1820
1821 @ForceInline
1822 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1823 boolean expected,
1824 boolean x) {
1825 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1826 }
1827
1828 @ForceInline
1829 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1830 boolean expected,
1831 boolean x) {
1832 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1833 }
1834
1835 @ForceInline
1836 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1837 boolean expected,
1838 boolean x) {
1839 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1840 }
1841
1842 /**
1843 * Atomically updates Java variable to {@code x} if it is currently
1844 * holding {@code expected}.
1845 *
1846 * <p>This operation has memory semantics of a {@code volatile} read
1847 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1848 *
1849 * @return {@code true} if successful
1850 */
1851 @ForceInline
1852 public final boolean compareAndSetFloat(Object o, long offset,
1853 float expected,
1854 float x) {
1855 return compareAndSetInt(o, offset,
1856 Float.floatToRawIntBits(expected),
1857 Float.floatToRawIntBits(x));
1858 }
1859
1860 @ForceInline
1861 public final float compareAndExchangeFloat(Object o, long offset,
1862 float expected,
1863 float x) {
1864 int w = compareAndExchangeInt(o, offset,
1865 Float.floatToRawIntBits(expected),
1866 Float.floatToRawIntBits(x));
1867 return Float.intBitsToFloat(w);
1868 }
1869
1870 @ForceInline
1871 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1872 float expected,
1873 float x) {
1874 int w = compareAndExchangeIntAcquire(o, offset,
1875 Float.floatToRawIntBits(expected),
1876 Float.floatToRawIntBits(x));
1877 return Float.intBitsToFloat(w);
1878 }
1879
1880 @ForceInline
1881 public final float compareAndExchangeFloatRelease(Object o, long offset,
1882 float expected,
1883 float x) {
1884 int w = compareAndExchangeIntRelease(o, offset,
1885 Float.floatToRawIntBits(expected),
1886 Float.floatToRawIntBits(x));
1887 return Float.intBitsToFloat(w);
1888 }
1889
1890 @ForceInline
1891 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
1892 float expected,
1893 float x) {
1894 return weakCompareAndSetIntPlain(o, offset,
1895 Float.floatToRawIntBits(expected),
1896 Float.floatToRawIntBits(x));
1897 }
1898
1899 @ForceInline
1900 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
1901 float expected,
1902 float x) {
1903 return weakCompareAndSetIntAcquire(o, offset,
1904 Float.floatToRawIntBits(expected),
1905 Float.floatToRawIntBits(x));
1906 }
1907
1908 @ForceInline
1909 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
1910 float expected,
1911 float x) {
1912 return weakCompareAndSetIntRelease(o, offset,
1913 Float.floatToRawIntBits(expected),
1914 Float.floatToRawIntBits(x));
1915 }
1916
1917 @ForceInline
1918 public final boolean weakCompareAndSetFloat(Object o, long offset,
1919 float expected,
1920 float x) {
1921 return weakCompareAndSetInt(o, offset,
1922 Float.floatToRawIntBits(expected),
1923 Float.floatToRawIntBits(x));
1924 }
1925
1926 /**
1927 * Atomically updates Java variable to {@code x} if it is currently
1928 * holding {@code expected}.
1929 *
1930 * <p>This operation has memory semantics of a {@code volatile} read
1931 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1932 *
1933 * @return {@code true} if successful
1934 */
1935 @ForceInline
1936 public final boolean compareAndSetDouble(Object o, long offset,
1937 double expected,
1938 double x) {
1939 return compareAndSetLong(o, offset,
1940 Double.doubleToRawLongBits(expected),
1941 Double.doubleToRawLongBits(x));
1942 }
1943
1944 @ForceInline
1945 public final double compareAndExchangeDouble(Object o, long offset,
1946 double expected,
1947 double x) {
1948 long w = compareAndExchangeLong(o, offset,
1949 Double.doubleToRawLongBits(expected),
1950 Double.doubleToRawLongBits(x));
1951 return Double.longBitsToDouble(w);
1952 }
1953
1954 @ForceInline
1955 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
1956 double expected,
1957 double x) {
1958 long w = compareAndExchangeLongAcquire(o, offset,
1959 Double.doubleToRawLongBits(expected),
1960 Double.doubleToRawLongBits(x));
1961 return Double.longBitsToDouble(w);
1962 }
1963
1964 @ForceInline
1965 public final double compareAndExchangeDoubleRelease(Object o, long offset,
1966 double expected,
1967 double x) {
1968 long w = compareAndExchangeLongRelease(o, offset,
1969 Double.doubleToRawLongBits(expected),
1970 Double.doubleToRawLongBits(x));
1971 return Double.longBitsToDouble(w);
1972 }
1973
1974 @ForceInline
1975 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
1976 double expected,
1977 double x) {
1978 return weakCompareAndSetLongPlain(o, offset,
1979 Double.doubleToRawLongBits(expected),
1980 Double.doubleToRawLongBits(x));
1981 }
1982
1983 @ForceInline
1984 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
1985 double expected,
1986 double x) {
1987 return weakCompareAndSetLongAcquire(o, offset,
1988 Double.doubleToRawLongBits(expected),
1989 Double.doubleToRawLongBits(x));
1990 }
1991
1992 @ForceInline
1993 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
1994 double expected,
1995 double x) {
1996 return weakCompareAndSetLongRelease(o, offset,
1997 Double.doubleToRawLongBits(expected),
1998 Double.doubleToRawLongBits(x));
1999 }
2000
2001 @ForceInline
2002 public final boolean weakCompareAndSetDouble(Object o, long offset,
2003 double expected,
2004 double x) {
2005 return weakCompareAndSetLong(o, offset,
2006 Double.doubleToRawLongBits(expected),
2007 Double.doubleToRawLongBits(x));
2008 }
2009
2010 /**
2011 * Atomically updates Java variable to {@code x} if it is currently
2012 * holding {@code expected}.
2013 *
2014 * <p>This operation has memory semantics of a {@code volatile} read
2015 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2016 *
2017 * @return {@code true} if successful
2018 */
2019 @IntrinsicCandidate
2020 public final native boolean compareAndSetLong(Object o, long offset,
2021 long expected,
2022 long x);
2023
2024 @IntrinsicCandidate
2025 public final native long compareAndExchangeLong(Object o, long offset,
2026 long expected,
2027 long x);
2028
2029 @IntrinsicCandidate
2030 public final long compareAndExchangeLongAcquire(Object o, long offset,
2031 long expected,
2032 long x) {
2033 return compareAndExchangeLong(o, offset, expected, x);
2034 }
2035
2036 @IntrinsicCandidate
2037 public final long compareAndExchangeLongRelease(Object o, long offset,
2038 long expected,
2039 long x) {
2040 return compareAndExchangeLong(o, offset, expected, x);
2041 }
2042
2043 @IntrinsicCandidate
2044 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2045 long expected,
2046 long x) {
2047 return compareAndSetLong(o, offset, expected, x);
2048 }
2049
2050 @IntrinsicCandidate
2051 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2052 long expected,
2053 long x) {
2054 return compareAndSetLong(o, offset, expected, x);
2055 }
2056
2057 @IntrinsicCandidate
2058 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2059 long expected,
2060 long x) {
2061 return compareAndSetLong(o, offset, expected, x);
2062 }
2063
2064 @IntrinsicCandidate
2065 public final boolean weakCompareAndSetLong(Object o, long offset,
2066 long expected,
2067 long x) {
2068 return compareAndSetLong(o, offset, expected, x);
2069 }
2070
2071 /**
2072 * Fetches a reference value from a given Java variable, with volatile
2073 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2074 */
2075 @IntrinsicCandidate
2076 public native Object getReferenceVolatile(Object o, long offset);
2077
2078 /**
2079 * Stores a reference value into a given Java variable, with
2080 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2081 */
2082 @IntrinsicCandidate
2083 public native void putReferenceVolatile(Object o, long offset, Object x);
2084
2085 /** Volatile version of {@link #getInt(Object, long)} */
2086 @IntrinsicCandidate
2087 public native int getIntVolatile(Object o, long offset);
2088
2089 /** Volatile version of {@link #putInt(Object, long, int)} */
2090 @IntrinsicCandidate
2091 public native void putIntVolatile(Object o, long offset, int x);
2092
2093 /** Volatile version of {@link #getBoolean(Object, long)} */
2094 @IntrinsicCandidate
2095 public native boolean getBooleanVolatile(Object o, long offset);
2096
2097 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2098 @IntrinsicCandidate
2099 public native void putBooleanVolatile(Object o, long offset, boolean x);
2100
2101 /** Volatile version of {@link #getByte(Object, long)} */
2102 @IntrinsicCandidate
2103 public native byte getByteVolatile(Object o, long offset);
2104
2105 /** Volatile version of {@link #putByte(Object, long, byte)} */
2106 @IntrinsicCandidate
2107 public native void putByteVolatile(Object o, long offset, byte x);
2108
2109 /** Volatile version of {@link #getShort(Object, long)} */
2110 @IntrinsicCandidate
2111 public native short getShortVolatile(Object o, long offset);
2112
2113 /** Volatile version of {@link #putShort(Object, long, short)} */
2114 @IntrinsicCandidate
2115 public native void putShortVolatile(Object o, long offset, short x);
2116
2117 /** Volatile version of {@link #getChar(Object, long)} */
2118 @IntrinsicCandidate
2119 public native char getCharVolatile(Object o, long offset);
2120
2121 /** Volatile version of {@link #putChar(Object, long, char)} */
2122 @IntrinsicCandidate
2123 public native void putCharVolatile(Object o, long offset, char x);
2124
2125 /** Volatile version of {@link #getLong(Object, long)} */
2126 @IntrinsicCandidate
2127 public native long getLongVolatile(Object o, long offset);
2128
2129 /** Volatile version of {@link #putLong(Object, long, long)} */
2130 @IntrinsicCandidate
2131 public native void putLongVolatile(Object o, long offset, long x);
2132
2133 /** Volatile version of {@link #getFloat(Object, long)} */
2134 @IntrinsicCandidate
2135 public native float getFloatVolatile(Object o, long offset);
2136
2137 /** Volatile version of {@link #putFloat(Object, long, float)} */
2138 @IntrinsicCandidate
2139 public native void putFloatVolatile(Object o, long offset, float x);
2140
2141 /** Volatile version of {@link #getDouble(Object, long)} */
2142 @IntrinsicCandidate
2143 public native double getDoubleVolatile(Object o, long offset);
2144
2145 /** Volatile version of {@link #putDouble(Object, long, double)} */
2146 @IntrinsicCandidate
2147 public native void putDoubleVolatile(Object o, long offset, double x);
2148
2149
2150
2151 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2152 @IntrinsicCandidate
2153 public final Object getReferenceAcquire(Object o, long offset) {
2154 return getReferenceVolatile(o, offset);
2155 }
2156
2157 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2158 @IntrinsicCandidate
2159 public final boolean getBooleanAcquire(Object o, long offset) {
2160 return getBooleanVolatile(o, offset);
2161 }
2162
2163 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2164 @IntrinsicCandidate
2165 public final byte getByteAcquire(Object o, long offset) {
2166 return getByteVolatile(o, offset);
2167 }
2168
2169 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2170 @IntrinsicCandidate
2171 public final short getShortAcquire(Object o, long offset) {
2172 return getShortVolatile(o, offset);
2173 }
2174
2175 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2176 @IntrinsicCandidate
2177 public final char getCharAcquire(Object o, long offset) {
2178 return getCharVolatile(o, offset);
2179 }
2180
2181 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2182 @IntrinsicCandidate
2183 public final int getIntAcquire(Object o, long offset) {
2184 return getIntVolatile(o, offset);
2185 }
2186
2187 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2188 @IntrinsicCandidate
2189 public final float getFloatAcquire(Object o, long offset) {
2190 return getFloatVolatile(o, offset);
2191 }
2192
2193 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2194 @IntrinsicCandidate
2195 public final long getLongAcquire(Object o, long offset) {
2196 return getLongVolatile(o, offset);
2197 }
2198
2199 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2200 @IntrinsicCandidate
2201 public final double getDoubleAcquire(Object o, long offset) {
2202 return getDoubleVolatile(o, offset);
2203 }
2204
2205 /*
2206 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2207 * that do not guarantee immediate visibility of the store to
2208 * other threads. This method is generally only useful if the
2209 * underlying field is a Java volatile (or if an array cell, one
2210 * that is otherwise only accessed using volatile accesses).
2211 *
2212 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2213 */
2214
2215 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2216 @IntrinsicCandidate
2217 public final void putReferenceRelease(Object o, long offset, Object x) {
2218 putReferenceVolatile(o, offset, x);
2219 }
2220
2221 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2222 @IntrinsicCandidate
2223 public final void putBooleanRelease(Object o, long offset, boolean x) {
2224 putBooleanVolatile(o, offset, x);
2225 }
2226
2227 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2228 @IntrinsicCandidate
2229 public final void putByteRelease(Object o, long offset, byte x) {
2230 putByteVolatile(o, offset, x);
2231 }
2232
2233 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2234 @IntrinsicCandidate
2235 public final void putShortRelease(Object o, long offset, short x) {
2236 putShortVolatile(o, offset, x);
2237 }
2238
2239 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2240 @IntrinsicCandidate
2241 public final void putCharRelease(Object o, long offset, char x) {
2242 putCharVolatile(o, offset, x);
2243 }
2244
2245 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2246 @IntrinsicCandidate
2247 public final void putIntRelease(Object o, long offset, int x) {
2248 putIntVolatile(o, offset, x);
2249 }
2250
2251 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2252 @IntrinsicCandidate
2253 public final void putFloatRelease(Object o, long offset, float x) {
2254 putFloatVolatile(o, offset, x);
2255 }
2256
2257 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2258 @IntrinsicCandidate
2259 public final void putLongRelease(Object o, long offset, long x) {
2260 putLongVolatile(o, offset, x);
2261 }
2262
2263 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2264 @IntrinsicCandidate
2265 public final void putDoubleRelease(Object o, long offset, double x) {
2266 putDoubleVolatile(o, offset, x);
2267 }
2268
2269 // ------------------------------ Opaque --------------------------------------
2270
2271 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2272 @IntrinsicCandidate
2273 public final Object getReferenceOpaque(Object o, long offset) {
2274 return getReferenceVolatile(o, offset);
2275 }
2276
2277 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2278 @IntrinsicCandidate
2279 public final boolean getBooleanOpaque(Object o, long offset) {
2280 return getBooleanVolatile(o, offset);
2281 }
2282
2283 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2284 @IntrinsicCandidate
2285 public final byte getByteOpaque(Object o, long offset) {
2286 return getByteVolatile(o, offset);
2287 }
2288
2289 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2290 @IntrinsicCandidate
2291 public final short getShortOpaque(Object o, long offset) {
2292 return getShortVolatile(o, offset);
2293 }
2294
2295 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2296 @IntrinsicCandidate
2297 public final char getCharOpaque(Object o, long offset) {
2298 return getCharVolatile(o, offset);
2299 }
2300
2301 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2302 @IntrinsicCandidate
2303 public final int getIntOpaque(Object o, long offset) {
2304 return getIntVolatile(o, offset);
2305 }
2306
2307 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2308 @IntrinsicCandidate
2309 public final float getFloatOpaque(Object o, long offset) {
2310 return getFloatVolatile(o, offset);
2311 }
2312
2313 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2314 @IntrinsicCandidate
2315 public final long getLongOpaque(Object o, long offset) {
2316 return getLongVolatile(o, offset);
2317 }
2318
2319 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2320 @IntrinsicCandidate
2321 public final double getDoubleOpaque(Object o, long offset) {
2322 return getDoubleVolatile(o, offset);
2323 }
2324
2325 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2326 @IntrinsicCandidate
2327 public final void putReferenceOpaque(Object o, long offset, Object x) {
2328 putReferenceVolatile(o, offset, x);
2329 }
2330
2331 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2332 @IntrinsicCandidate
2333 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2334 putBooleanVolatile(o, offset, x);
2335 }
2336
2337 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2338 @IntrinsicCandidate
2339 public final void putByteOpaque(Object o, long offset, byte x) {
2340 putByteVolatile(o, offset, x);
2341 }
2342
2343 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2344 @IntrinsicCandidate
2345 public final void putShortOpaque(Object o, long offset, short x) {
2346 putShortVolatile(o, offset, x);
2347 }
2348
2349 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2350 @IntrinsicCandidate
2351 public final void putCharOpaque(Object o, long offset, char x) {
2352 putCharVolatile(o, offset, x);
2353 }
2354
2355 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2356 @IntrinsicCandidate
2357 public final void putIntOpaque(Object o, long offset, int x) {
2358 putIntVolatile(o, offset, x);
2359 }
2360
2361 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2362 @IntrinsicCandidate
2363 public final void putFloatOpaque(Object o, long offset, float x) {
2364 putFloatVolatile(o, offset, x);
2365 }
2366
2367 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2368 @IntrinsicCandidate
2369 public final void putLongOpaque(Object o, long offset, long x) {
2370 putLongVolatile(o, offset, x);
2371 }
2372
2373 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2374 @IntrinsicCandidate
2375 public final void putDoubleOpaque(Object o, long offset, double x) {
2376 putDoubleVolatile(o, offset, x);
2377 }
2378
2379 /**
2380 * Unblocks the given thread blocked on {@code park}, or, if it is
2381 * not blocked, causes the subsequent call to {@code park} not to
2382 * block. Note: this operation is "unsafe" solely because the
2383 * caller must somehow ensure that the thread has not been
2384 * destroyed. Nothing special is usually required to ensure this
2385 * when called from Java (in which there will ordinarily be a live
2386 * reference to the thread) but this is not nearly-automatically
2387 * so when calling from native code.
2388 *
2389 * @param thread the thread to unpark.
2390 */
2391 @IntrinsicCandidate
2392 public native void unpark(Object thread);
2393
2394 /**
2395 * Blocks current thread, returning when a balancing
2396 * {@code unpark} occurs, or a balancing {@code unpark} has
2397 * already occurred, or the thread is interrupted, or, if not
2398 * absolute and time is not zero, the given time nanoseconds have
2399 * elapsed, or if absolute, the given deadline in milliseconds
2400 * since Epoch has passed, or spuriously (i.e., returning for no
2401 * "reason"). Note: This operation is in the Unsafe class only
2402 * because {@code unpark} is, so it would be strange to place it
2403 * elsewhere.
2404 */
2405 @IntrinsicCandidate
2406 public native void park(boolean isAbsolute, long time);
2407
2408 /**
2409 * Gets the load average in the system run queue assigned
2410 * to the available processors averaged over various periods of time.
2411 * This method retrieves the given {@code nelem} samples and
2412 * assigns to the elements of the given {@code loadavg} array.
2413 * The system imposes a maximum of 3 samples, representing
2414 * averages over the last 1, 5, and 15 minutes, respectively.
2415 *
2416 * @param loadavg an array of double of size nelems
2417 * @param nelems the number of samples to be retrieved and
2418 * must be 1 to 3.
2419 *
2420 * @return the number of samples actually retrieved; or -1
2421 * if the load average is unobtainable.
2422 */
2423 public int getLoadAverage(double[] loadavg, int nelems) {
2424 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2425 throw new ArrayIndexOutOfBoundsException();
2426 }
2427
2428 return getLoadAverage0(loadavg, nelems);
2429 }
2430
2431 // The following contain CAS-based Java implementations used on
2432 // platforms not supporting native instructions
2433
2434 /**
2435 * Atomically adds the given value to the current value of a field
2436 * or array element within the given object {@code o}
2437 * at the given {@code offset}.
2438 *
2439 * @param o object/array to update the field/element in
2440 * @param offset field/element offset
2441 * @param delta the value to add
2442 * @return the previous value
2443 * @since 1.8
2444 */
2445 @IntrinsicCandidate
2446 public final int getAndAddInt(Object o, long offset, int delta) {
2447 int v;
2448 do {
2449 v = getIntVolatile(o, offset);
2450 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2451 return v;
2452 }
2453
2454 @ForceInline
2455 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2456 int v;
2457 do {
2458 v = getInt(o, offset);
2459 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2460 return v;
2461 }
2462
2463 @ForceInline
2464 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2465 int v;
2466 do {
2467 v = getIntAcquire(o, offset);
2468 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2469 return v;
2470 }
2471
2472 /**
2473 * Atomically adds the given value to the current value of a field
2474 * or array element within the given object {@code o}
2475 * at the given {@code offset}.
2476 *
2477 * @param o object/array to update the field/element in
2478 * @param offset field/element offset
2479 * @param delta the value to add
2480 * @return the previous value
2481 * @since 1.8
2482 */
2483 @IntrinsicCandidate
2484 public final long getAndAddLong(Object o, long offset, long delta) {
2485 long v;
2486 do {
2487 v = getLongVolatile(o, offset);
2488 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2489 return v;
2490 }
2491
2492 @ForceInline
2493 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2494 long v;
2495 do {
2496 v = getLong(o, offset);
2497 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2498 return v;
2499 }
2500
2501 @ForceInline
2502 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2503 long v;
2504 do {
2505 v = getLongAcquire(o, offset);
2506 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2507 return v;
2508 }
2509
2510 @IntrinsicCandidate
2511 public final byte getAndAddByte(Object o, long offset, byte delta) {
2512 byte v;
2513 do {
2514 v = getByteVolatile(o, offset);
2515 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2516 return v;
2517 }
2518
2519 @ForceInline
2520 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2521 byte v;
2522 do {
2523 v = getByte(o, offset);
2524 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2525 return v;
2526 }
2527
2528 @ForceInline
2529 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2530 byte v;
2531 do {
2532 v = getByteAcquire(o, offset);
2533 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2534 return v;
2535 }
2536
2537 @IntrinsicCandidate
2538 public final short getAndAddShort(Object o, long offset, short delta) {
2539 short v;
2540 do {
2541 v = getShortVolatile(o, offset);
2542 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2543 return v;
2544 }
2545
2546 @ForceInline
2547 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2548 short v;
2549 do {
2550 v = getShort(o, offset);
2551 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2552 return v;
2553 }
2554
2555 @ForceInline
2556 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2557 short v;
2558 do {
2559 v = getShortAcquire(o, offset);
2560 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2561 return v;
2562 }
2563
2564 @ForceInline
2565 public final char getAndAddChar(Object o, long offset, char delta) {
2566 return (char) getAndAddShort(o, offset, (short) delta);
2567 }
2568
2569 @ForceInline
2570 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2571 return (char) getAndAddShortRelease(o, offset, (short) delta);
2572 }
2573
2574 @ForceInline
2575 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2576 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2577 }
2578
2579 @ForceInline
2580 public final float getAndAddFloat(Object o, long offset, float delta) {
2581 int expectedBits;
2582 float v;
2583 do {
2584 // Load and CAS with the raw bits to avoid issues with NaNs and
2585 // possible bit conversion from signaling NaNs to quiet NaNs that
2586 // may result in the loop not terminating.
2587 expectedBits = getIntVolatile(o, offset);
2588 v = Float.intBitsToFloat(expectedBits);
2589 } while (!weakCompareAndSetInt(o, offset,
2590 expectedBits, Float.floatToRawIntBits(v + delta)));
2591 return v;
2592 }
2593
2594 @ForceInline
2595 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2596 int expectedBits;
2597 float v;
2598 do {
2599 // Load and CAS with the raw bits to avoid issues with NaNs and
2600 // possible bit conversion from signaling NaNs to quiet NaNs that
2601 // may result in the loop not terminating.
2602 expectedBits = getInt(o, offset);
2603 v = Float.intBitsToFloat(expectedBits);
2604 } while (!weakCompareAndSetIntRelease(o, offset,
2605 expectedBits, Float.floatToRawIntBits(v + delta)));
2606 return v;
2607 }
2608
2609 @ForceInline
2610 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2611 int expectedBits;
2612 float v;
2613 do {
2614 // Load and CAS with the raw bits to avoid issues with NaNs and
2615 // possible bit conversion from signaling NaNs to quiet NaNs that
2616 // may result in the loop not terminating.
2617 expectedBits = getIntAcquire(o, offset);
2618 v = Float.intBitsToFloat(expectedBits);
2619 } while (!weakCompareAndSetIntAcquire(o, offset,
2620 expectedBits, Float.floatToRawIntBits(v + delta)));
2621 return v;
2622 }
2623
2624 @ForceInline
2625 public final double getAndAddDouble(Object o, long offset, double delta) {
2626 long expectedBits;
2627 double v;
2628 do {
2629 // Load and CAS with the raw bits to avoid issues with NaNs and
2630 // possible bit conversion from signaling NaNs to quiet NaNs that
2631 // may result in the loop not terminating.
2632 expectedBits = getLongVolatile(o, offset);
2633 v = Double.longBitsToDouble(expectedBits);
2634 } while (!weakCompareAndSetLong(o, offset,
2635 expectedBits, Double.doubleToRawLongBits(v + delta)));
2636 return v;
2637 }
2638
2639 @ForceInline
2640 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2641 long expectedBits;
2642 double v;
2643 do {
2644 // Load and CAS with the raw bits to avoid issues with NaNs and
2645 // possible bit conversion from signaling NaNs to quiet NaNs that
2646 // may result in the loop not terminating.
2647 expectedBits = getLong(o, offset);
2648 v = Double.longBitsToDouble(expectedBits);
2649 } while (!weakCompareAndSetLongRelease(o, offset,
2650 expectedBits, Double.doubleToRawLongBits(v + delta)));
2651 return v;
2652 }
2653
2654 @ForceInline
2655 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2656 long expectedBits;
2657 double v;
2658 do {
2659 // Load and CAS with the raw bits to avoid issues with NaNs and
2660 // possible bit conversion from signaling NaNs to quiet NaNs that
2661 // may result in the loop not terminating.
2662 expectedBits = getLongAcquire(o, offset);
2663 v = Double.longBitsToDouble(expectedBits);
2664 } while (!weakCompareAndSetLongAcquire(o, offset,
2665 expectedBits, Double.doubleToRawLongBits(v + delta)));
2666 return v;
2667 }
2668
2669 /**
2670 * Atomically exchanges the given value with the current value of
2671 * a field or array element within the given object {@code o}
2672 * at the given {@code offset}.
2673 *
2674 * @param o object/array to update the field/element in
2675 * @param offset field/element offset
2676 * @param newValue new value
2677 * @return the previous value
2678 * @since 1.8
2679 */
2680 @IntrinsicCandidate
2681 public final int getAndSetInt(Object o, long offset, int newValue) {
2682 int v;
2683 do {
2684 v = getIntVolatile(o, offset);
2685 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2686 return v;
2687 }
2688
2689 @ForceInline
2690 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2691 int v;
2692 do {
2693 v = getInt(o, offset);
2694 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2695 return v;
2696 }
2697
2698 @ForceInline
2699 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2700 int v;
2701 do {
2702 v = getIntAcquire(o, offset);
2703 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2704 return v;
2705 }
2706
2707 /**
2708 * Atomically exchanges the given value with the current value of
2709 * a field or array element within the given object {@code o}
2710 * at the given {@code offset}.
2711 *
2712 * @param o object/array to update the field/element in
2713 * @param offset field/element offset
2714 * @param newValue new value
2715 * @return the previous value
2716 * @since 1.8
2717 */
2718 @IntrinsicCandidate
2719 public final long getAndSetLong(Object o, long offset, long newValue) {
2720 long v;
2721 do {
2722 v = getLongVolatile(o, offset);
2723 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2724 return v;
2725 }
2726
2727 @ForceInline
2728 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2729 long v;
2730 do {
2731 v = getLong(o, offset);
2732 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2733 return v;
2734 }
2735
2736 @ForceInline
2737 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2738 long v;
2739 do {
2740 v = getLongAcquire(o, offset);
2741 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2742 return v;
2743 }
2744
2745 /**
2746 * Atomically exchanges the given reference value with the current
2747 * reference value of a field or array element within the given
2748 * object {@code o} at the given {@code offset}.
2749 *
2750 * @param o object/array to update the field/element in
2751 * @param offset field/element offset
2752 * @param newValue new value
2753 * @return the previous value
2754 * @since 1.8
2755 */
2756 @IntrinsicCandidate
2757 public final Object getAndSetReference(Object o, long offset, Object newValue) {
2758 Object v;
2759 do {
2760 v = getReferenceVolatile(o, offset);
2761 } while (!weakCompareAndSetReference(o, offset, v, newValue));
2762 return v;
2763 }
2764
2765 @ForceInline
2766 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
2767 Object v;
2768 do {
2769 v = getReference(o, offset);
2770 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
2771 return v;
2772 }
2773
2774 @ForceInline
2775 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
2776 Object v;
2777 do {
2778 v = getReferenceAcquire(o, offset);
2779 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
2780 return v;
2781 }
2782
2783 @IntrinsicCandidate
2784 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2785 byte v;
2786 do {
2787 v = getByteVolatile(o, offset);
2788 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2789 return v;
2790 }
2791
2792 @ForceInline
2793 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2794 byte v;
2795 do {
2796 v = getByte(o, offset);
2797 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2798 return v;
2799 }
2800
2801 @ForceInline
2802 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2803 byte v;
2804 do {
2805 v = getByteAcquire(o, offset);
2806 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2807 return v;
2808 }
2809
2810 @ForceInline
2811 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2812 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2813 }
2814
2815 @ForceInline
2816 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2817 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2818 }
2819
2820 @ForceInline
2821 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2822 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2823 }
2824
2825 @IntrinsicCandidate
2826 public final short getAndSetShort(Object o, long offset, short newValue) {
2827 short v;
2828 do {
2829 v = getShortVolatile(o, offset);
2830 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2831 return v;
2832 }
2833
2834 @ForceInline
2835 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
2836 short v;
2837 do {
2838 v = getShort(o, offset);
2839 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
2840 return v;
2841 }
2842
2843 @ForceInline
2844 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
2845 short v;
2846 do {
2847 v = getShortAcquire(o, offset);
2848 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
2849 return v;
2850 }
2851
2852 @ForceInline
2853 public final char getAndSetChar(Object o, long offset, char newValue) {
2854 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2855 }
2856
2857 @ForceInline
2858 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
2859 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
2860 }
2861
2862 @ForceInline
2863 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
2864 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
2865 }
2866
2867 @ForceInline
2868 public final float getAndSetFloat(Object o, long offset, float newValue) {
2869 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
2870 return Float.intBitsToFloat(v);
2871 }
2872
2873 @ForceInline
2874 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
2875 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
2876 return Float.intBitsToFloat(v);
2877 }
2878
2879 @ForceInline
2880 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
2881 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
2882 return Float.intBitsToFloat(v);
2883 }
2884
2885 @ForceInline
2886 public final double getAndSetDouble(Object o, long offset, double newValue) {
2887 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
2888 return Double.longBitsToDouble(v);
2889 }
2890
2891 @ForceInline
2892 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
2893 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
2894 return Double.longBitsToDouble(v);
2895 }
2896
2897 @ForceInline
2898 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
2899 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
2900 return Double.longBitsToDouble(v);
2901 }
2902
2903
2904 // The following contain CAS-based Java implementations used on
2905 // platforms not supporting native instructions
2906
2907 @ForceInline
2908 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
2909 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
2910 }
2911
2912 @ForceInline
2913 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
2914 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
2915 }
2916
2917 @ForceInline
2918 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
2919 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
2920 }
2921
2922 @ForceInline
2923 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
2924 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
2925 }
2926
2927 @ForceInline
2928 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
2929 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
2930 }
2931
2932 @ForceInline
2933 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
2934 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
2935 }
2936
2937 @ForceInline
2938 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
2939 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
2940 }
2941
2942 @ForceInline
2943 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
2944 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
2945 }
2946
2947 @ForceInline
2948 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
2949 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
2950 }
2951
2952
2953 @ForceInline
2954 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
2955 byte current;
2956 do {
2957 current = getByteVolatile(o, offset);
2958 } while (!weakCompareAndSetByte(o, offset,
2959 current, (byte) (current | mask)));
2960 return current;
2961 }
2962
2963 @ForceInline
2964 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
2965 byte current;
2966 do {
2967 current = getByte(o, offset);
2968 } while (!weakCompareAndSetByteRelease(o, offset,
2969 current, (byte) (current | mask)));
2970 return current;
2971 }
2972
2973 @ForceInline
2974 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
2975 byte current;
2976 do {
2977 // Plain read, the value is a hint, the acquire CAS does the work
2978 current = getByte(o, offset);
2979 } while (!weakCompareAndSetByteAcquire(o, offset,
2980 current, (byte) (current | mask)));
2981 return current;
2982 }
2983
2984 @ForceInline
2985 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
2986 byte current;
2987 do {
2988 current = getByteVolatile(o, offset);
2989 } while (!weakCompareAndSetByte(o, offset,
2990 current, (byte) (current & mask)));
2991 return current;
2992 }
2993
2994 @ForceInline
2995 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
2996 byte current;
2997 do {
2998 current = getByte(o, offset);
2999 } while (!weakCompareAndSetByteRelease(o, offset,
3000 current, (byte) (current & mask)));
3001 return current;
3002 }
3003
3004 @ForceInline
3005 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3006 byte current;
3007 do {
3008 // Plain read, the value is a hint, the acquire CAS does the work
3009 current = getByte(o, offset);
3010 } while (!weakCompareAndSetByteAcquire(o, offset,
3011 current, (byte) (current & mask)));
3012 return current;
3013 }
3014
3015 @ForceInline
3016 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3017 byte current;
3018 do {
3019 current = getByteVolatile(o, offset);
3020 } while (!weakCompareAndSetByte(o, offset,
3021 current, (byte) (current ^ mask)));
3022 return current;
3023 }
3024
3025 @ForceInline
3026 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3027 byte current;
3028 do {
3029 current = getByte(o, offset);
3030 } while (!weakCompareAndSetByteRelease(o, offset,
3031 current, (byte) (current ^ mask)));
3032 return current;
3033 }
3034
3035 @ForceInline
3036 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3037 byte current;
3038 do {
3039 // Plain read, the value is a hint, the acquire CAS does the work
3040 current = getByte(o, offset);
3041 } while (!weakCompareAndSetByteAcquire(o, offset,
3042 current, (byte) (current ^ mask)));
3043 return current;
3044 }
3045
3046
3047 @ForceInline
3048 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3049 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3050 }
3051
3052 @ForceInline
3053 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3054 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3055 }
3056
3057 @ForceInline
3058 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3059 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3060 }
3061
3062 @ForceInline
3063 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3064 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3065 }
3066
3067 @ForceInline
3068 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3069 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3070 }
3071
3072 @ForceInline
3073 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3074 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3075 }
3076
3077 @ForceInline
3078 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3079 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3080 }
3081
3082 @ForceInline
3083 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3084 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3085 }
3086
3087 @ForceInline
3088 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3089 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3090 }
3091
3092
3093 @ForceInline
3094 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3095 short current;
3096 do {
3097 current = getShortVolatile(o, offset);
3098 } while (!weakCompareAndSetShort(o, offset,
3099 current, (short) (current | mask)));
3100 return current;
3101 }
3102
3103 @ForceInline
3104 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3105 short current;
3106 do {
3107 current = getShort(o, offset);
3108 } while (!weakCompareAndSetShortRelease(o, offset,
3109 current, (short) (current | mask)));
3110 return current;
3111 }
3112
3113 @ForceInline
3114 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3115 short current;
3116 do {
3117 // Plain read, the value is a hint, the acquire CAS does the work
3118 current = getShort(o, offset);
3119 } while (!weakCompareAndSetShortAcquire(o, offset,
3120 current, (short) (current | mask)));
3121 return current;
3122 }
3123
3124 @ForceInline
3125 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3126 short current;
3127 do {
3128 current = getShortVolatile(o, offset);
3129 } while (!weakCompareAndSetShort(o, offset,
3130 current, (short) (current & mask)));
3131 return current;
3132 }
3133
3134 @ForceInline
3135 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3136 short current;
3137 do {
3138 current = getShort(o, offset);
3139 } while (!weakCompareAndSetShortRelease(o, offset,
3140 current, (short) (current & mask)));
3141 return current;
3142 }
3143
3144 @ForceInline
3145 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3146 short current;
3147 do {
3148 // Plain read, the value is a hint, the acquire CAS does the work
3149 current = getShort(o, offset);
3150 } while (!weakCompareAndSetShortAcquire(o, offset,
3151 current, (short) (current & mask)));
3152 return current;
3153 }
3154
3155 @ForceInline
3156 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3157 short current;
3158 do {
3159 current = getShortVolatile(o, offset);
3160 } while (!weakCompareAndSetShort(o, offset,
3161 current, (short) (current ^ mask)));
3162 return current;
3163 }
3164
3165 @ForceInline
3166 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3167 short current;
3168 do {
3169 current = getShort(o, offset);
3170 } while (!weakCompareAndSetShortRelease(o, offset,
3171 current, (short) (current ^ mask)));
3172 return current;
3173 }
3174
3175 @ForceInline
3176 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3177 short current;
3178 do {
3179 // Plain read, the value is a hint, the acquire CAS does the work
3180 current = getShort(o, offset);
3181 } while (!weakCompareAndSetShortAcquire(o, offset,
3182 current, (short) (current ^ mask)));
3183 return current;
3184 }
3185
3186
3187 @ForceInline
3188 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3189 int current;
3190 do {
3191 current = getIntVolatile(o, offset);
3192 } while (!weakCompareAndSetInt(o, offset,
3193 current, current | mask));
3194 return current;
3195 }
3196
3197 @ForceInline
3198 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3199 int current;
3200 do {
3201 current = getInt(o, offset);
3202 } while (!weakCompareAndSetIntRelease(o, offset,
3203 current, current | mask));
3204 return current;
3205 }
3206
3207 @ForceInline
3208 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3209 int current;
3210 do {
3211 // Plain read, the value is a hint, the acquire CAS does the work
3212 current = getInt(o, offset);
3213 } while (!weakCompareAndSetIntAcquire(o, offset,
3214 current, current | mask));
3215 return current;
3216 }
3217
3218 /**
3219 * Atomically replaces the current value of a field or array element within
3220 * the given object with the result of bitwise AND between the current value
3221 * and mask.
3222 *
3223 * @param o object/array to update the field/element in
3224 * @param offset field/element offset
3225 * @param mask the mask value
3226 * @return the previous value
3227 * @since 9
3228 */
3229 @ForceInline
3230 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3231 int current;
3232 do {
3233 current = getIntVolatile(o, offset);
3234 } while (!weakCompareAndSetInt(o, offset,
3235 current, current & mask));
3236 return current;
3237 }
3238
3239 @ForceInline
3240 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3241 int current;
3242 do {
3243 current = getInt(o, offset);
3244 } while (!weakCompareAndSetIntRelease(o, offset,
3245 current, current & mask));
3246 return current;
3247 }
3248
3249 @ForceInline
3250 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3251 int current;
3252 do {
3253 // Plain read, the value is a hint, the acquire CAS does the work
3254 current = getInt(o, offset);
3255 } while (!weakCompareAndSetIntAcquire(o, offset,
3256 current, current & mask));
3257 return current;
3258 }
3259
3260 @ForceInline
3261 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3262 int current;
3263 do {
3264 current = getIntVolatile(o, offset);
3265 } while (!weakCompareAndSetInt(o, offset,
3266 current, current ^ mask));
3267 return current;
3268 }
3269
3270 @ForceInline
3271 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3272 int current;
3273 do {
3274 current = getInt(o, offset);
3275 } while (!weakCompareAndSetIntRelease(o, offset,
3276 current, current ^ mask));
3277 return current;
3278 }
3279
3280 @ForceInline
3281 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3282 int current;
3283 do {
3284 // Plain read, the value is a hint, the acquire CAS does the work
3285 current = getInt(o, offset);
3286 } while (!weakCompareAndSetIntAcquire(o, offset,
3287 current, current ^ mask));
3288 return current;
3289 }
3290
3291
3292 @ForceInline
3293 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3294 long current;
3295 do {
3296 current = getLongVolatile(o, offset);
3297 } while (!weakCompareAndSetLong(o, offset,
3298 current, current | mask));
3299 return current;
3300 }
3301
3302 @ForceInline
3303 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3304 long current;
3305 do {
3306 current = getLong(o, offset);
3307 } while (!weakCompareAndSetLongRelease(o, offset,
3308 current, current | mask));
3309 return current;
3310 }
3311
3312 @ForceInline
3313 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3314 long current;
3315 do {
3316 // Plain read, the value is a hint, the acquire CAS does the work
3317 current = getLong(o, offset);
3318 } while (!weakCompareAndSetLongAcquire(o, offset,
3319 current, current | mask));
3320 return current;
3321 }
3322
3323 @ForceInline
3324 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3325 long current;
3326 do {
3327 current = getLongVolatile(o, offset);
3328 } while (!weakCompareAndSetLong(o, offset,
3329 current, current & mask));
3330 return current;
3331 }
3332
3333 @ForceInline
3334 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3335 long current;
3336 do {
3337 current = getLong(o, offset);
3338 } while (!weakCompareAndSetLongRelease(o, offset,
3339 current, current & mask));
3340 return current;
3341 }
3342
3343 @ForceInline
3344 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3345 long current;
3346 do {
3347 // Plain read, the value is a hint, the acquire CAS does the work
3348 current = getLong(o, offset);
3349 } while (!weakCompareAndSetLongAcquire(o, offset,
3350 current, current & mask));
3351 return current;
3352 }
3353
3354 @ForceInline
3355 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3356 long current;
3357 do {
3358 current = getLongVolatile(o, offset);
3359 } while (!weakCompareAndSetLong(o, offset,
3360 current, current ^ mask));
3361 return current;
3362 }
3363
3364 @ForceInline
3365 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3366 long current;
3367 do {
3368 current = getLong(o, offset);
3369 } while (!weakCompareAndSetLongRelease(o, offset,
3370 current, current ^ mask));
3371 return current;
3372 }
3373
3374 @ForceInline
3375 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3376 long current;
3377 do {
3378 // Plain read, the value is a hint, the acquire CAS does the work
3379 current = getLong(o, offset);
3380 } while (!weakCompareAndSetLongAcquire(o, offset,
3381 current, current ^ mask));
3382 return current;
3383 }
3384
3385
3386
3387 /**
3388 * Ensures that loads before the fence will not be reordered with loads and
3389 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3390 *
3391 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3392 * (an "acquire fence").
3393 *
3394 * Provides a LoadLoad barrier followed by a LoadStore barrier.
3395 *
3396 * @since 1.8
3397 */
3398 @IntrinsicCandidate
3399 public final void loadFence() {
3400 // If loadFence intrinsic is not available, fall back to full fence.
3401 fullFence();
3402 }
3403
3404 /**
3405 * Ensures that loads and stores before the fence will not be reordered with
3406 * stores after the fence; a "StoreStore plus LoadStore barrier".
3407 *
3408 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3409 * (a "release fence").
3410 *
3411 * Provides a StoreStore barrier followed by a LoadStore barrier.
3412 *
3413 * @since 1.8
3414 */
3415 @IntrinsicCandidate
3416 public final void storeFence() {
3417 // If storeFence intrinsic is not available, fall back to full fence.
3418 fullFence();
3419 }
3420
3421 /**
3422 * Ensures that loads and stores before the fence will not be reordered
3423 * with loads and stores after the fence. Implies the effects of both
3424 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3425 * barrier.
3426 *
3427 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3428 * @since 1.8
3429 */
3430 @IntrinsicCandidate
3431 public native void fullFence();
3432
3433 /**
3434 * Ensures that loads before the fence will not be reordered with
3435 * loads after the fence.
3436 *
3437 * @implNote
3438 * This method is operationally equivalent to {@link #loadFence()}.
3439 *
3440 * @since 9
3441 */
3442 public final void loadLoadFence() {
3443 loadFence();
3444 }
3445
3446 /**
3447 * Ensures that stores before the fence will not be reordered with
3448 * stores after the fence.
3449 *
3450 * @since 9
3451 */
3452 @IntrinsicCandidate
3453 public final void storeStoreFence() {
3454 // If storeStoreFence intrinsic is not available, fall back to storeFence.
3455 storeFence();
3456 }
3457
3458 /**
3459 * Throws IllegalAccessError; for use by the VM for access control
3460 * error support.
3461 * @since 1.8
3462 */
3463 private static void throwIllegalAccessError() {
3464 throw new IllegalAccessError();
3465 }
3466
3467 /**
3468 * Throws NoSuchMethodError; for use by the VM for redefinition support.
3469 * @since 13
3470 */
3471 private static void throwNoSuchMethodError() {
3472 throw new NoSuchMethodError();
3473 }
3474
3475 /**
3476 * @return Returns true if the native byte ordering of this
3477 * platform is big-endian, false if it is little-endian.
3478 */
3479 public final boolean isBigEndian() { return BIG_ENDIAN; }
3480
3481 /**
3482 * @return Returns true if this platform is capable of performing
3483 * accesses at addresses which are not aligned for the type of the
3484 * primitive type being accessed, false otherwise.
3485 */
3486 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
3487
3488 /**
3489 * Fetches a value at some byte offset into a given Java object.
3490 * More specifically, fetches a value within the given object
3491 * <code>o</code> at the given offset, or (if <code>o</code> is
3492 * null) from the memory address whose numerical value is the
3493 * given offset. <p>
3494 *
3495 * The specification of this method is the same as {@link
3496 * #getLong(Object, long)} except that the offset does not need to
3497 * have been obtained from {@link #objectFieldOffset} on the
3498 * {@link java.lang.reflect.Field} of some Java field. The value
3499 * in memory is raw data, and need not correspond to any Java
3500 * variable. Unless <code>o</code> is null, the value accessed
3501 * must be entirely within the allocated object. The endianness
3502 * of the value in memory is the endianness of the native platform.
3503 *
3504 * <p> The read will be atomic with respect to the largest power
3505 * of two that divides the GCD of the offset and the storage size.
3506 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3507 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3508 * respectively. There are no other guarantees of atomicity.
3509 * <p>
3510 * 8-byte atomicity is only guaranteed on platforms on which
3511 * support atomic accesses to longs.
3512 *
3513 * @param o Java heap object in which the value resides, if any, else
3514 * null
3515 * @param offset The offset in bytes from the start of the object
3516 * @return the value fetched from the indicated object
3517 * @throws RuntimeException No defined exceptions are thrown, not even
3518 * {@link NullPointerException}
3519 * @since 9
3520 */
3521 @IntrinsicCandidate
3522 public final long getLongUnaligned(Object o, long offset) {
3523 if ((offset & 7) == 0) {
3524 return getLong(o, offset);
3525 } else if ((offset & 3) == 0) {
3526 return makeLong(getInt(o, offset),
3527 getInt(o, offset + 4));
3528 } else if ((offset & 1) == 0) {
3529 return makeLong(getShort(o, offset),
3530 getShort(o, offset + 2),
3531 getShort(o, offset + 4),
3532 getShort(o, offset + 6));
3533 } else {
3534 return makeLong(getByte(o, offset),
3535 getByte(o, offset + 1),
3536 getByte(o, offset + 2),
3537 getByte(o, offset + 3),
3538 getByte(o, offset + 4),
3539 getByte(o, offset + 5),
3540 getByte(o, offset + 6),
3541 getByte(o, offset + 7));
3542 }
3543 }
3544 /**
3545 * As {@link #getLongUnaligned(Object, long)} but with an
3546 * additional argument which specifies the endianness of the value
3547 * as stored in memory.
3548 *
3549 * @param o Java heap object in which the variable resides
3550 * @param offset The offset in bytes from the start of the object
3551 * @param bigEndian The endianness of the value
3552 * @return the value fetched from the indicated object
3553 * @since 9
3554 */
3555 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3556 return convEndian(bigEndian, getLongUnaligned(o, offset));
3557 }
3558
3559 /** @see #getLongUnaligned(Object, long) */
3560 @IntrinsicCandidate
3561 public final int getIntUnaligned(Object o, long offset) {
3562 if ((offset & 3) == 0) {
3563 return getInt(o, offset);
3564 } else if ((offset & 1) == 0) {
3565 return makeInt(getShort(o, offset),
3566 getShort(o, offset + 2));
3567 } else {
3568 return makeInt(getByte(o, offset),
3569 getByte(o, offset + 1),
3570 getByte(o, offset + 2),
3571 getByte(o, offset + 3));
3572 }
3573 }
3574 /** @see #getLongUnaligned(Object, long, boolean) */
3575 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3576 return convEndian(bigEndian, getIntUnaligned(o, offset));
3577 }
3578
3579 /** @see #getLongUnaligned(Object, long) */
3580 @IntrinsicCandidate
3581 public final short getShortUnaligned(Object o, long offset) {
3582 if ((offset & 1) == 0) {
3583 return getShort(o, offset);
3584 } else {
3585 return makeShort(getByte(o, offset),
3586 getByte(o, offset + 1));
3587 }
3588 }
3589 /** @see #getLongUnaligned(Object, long, boolean) */
3590 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3591 return convEndian(bigEndian, getShortUnaligned(o, offset));
3592 }
3593
3594 /** @see #getLongUnaligned(Object, long) */
3595 @IntrinsicCandidate
3596 public final char getCharUnaligned(Object o, long offset) {
3597 if ((offset & 1) == 0) {
3598 return getChar(o, offset);
3599 } else {
3600 return (char)makeShort(getByte(o, offset),
3601 getByte(o, offset + 1));
3602 }
3603 }
3604
3605 /** @see #getLongUnaligned(Object, long, boolean) */
3606 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3607 return convEndian(bigEndian, getCharUnaligned(o, offset));
3608 }
3609
3610 /**
3611 * Stores a value at some byte offset into a given Java object.
3612 * <p>
3613 * The specification of this method is the same as {@link
3614 * #getLong(Object, long)} except that the offset does not need to
3615 * have been obtained from {@link #objectFieldOffset} on the
3616 * {@link java.lang.reflect.Field} of some Java field. The value
3617 * in memory is raw data, and need not correspond to any Java
3618 * variable. The endianness of the value in memory is the
3619 * endianness of the native platform.
3620 * <p>
3621 * The write will be atomic with respect to the largest power of
3622 * two that divides the GCD of the offset and the storage size.
3623 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3624 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3625 * respectively. There are no other guarantees of atomicity.
3626 * <p>
3627 * 8-byte atomicity is only guaranteed on platforms on which
3628 * support atomic accesses to longs.
3629 *
3630 * @param o Java heap object in which the value resides, if any, else
3631 * null
3632 * @param offset The offset in bytes from the start of the object
3633 * @param x the value to store
3634 * @throws RuntimeException No defined exceptions are thrown, not even
3635 * {@link NullPointerException}
3636 * @since 9
3637 */
3638 @IntrinsicCandidate
3639 public final void putLongUnaligned(Object o, long offset, long x) {
3640 if ((offset & 7) == 0) {
3641 putLong(o, offset, x);
3642 } else if ((offset & 3) == 0) {
3643 putLongParts(o, offset,
3644 (int)(x >> 0),
3645 (int)(x >>> 32));
3646 } else if ((offset & 1) == 0) {
3647 putLongParts(o, offset,
3648 (short)(x >>> 0),
3649 (short)(x >>> 16),
3650 (short)(x >>> 32),
3651 (short)(x >>> 48));
3652 } else {
3653 putLongParts(o, offset,
3654 (byte)(x >>> 0),
3655 (byte)(x >>> 8),
3656 (byte)(x >>> 16),
3657 (byte)(x >>> 24),
3658 (byte)(x >>> 32),
3659 (byte)(x >>> 40),
3660 (byte)(x >>> 48),
3661 (byte)(x >>> 56));
3662 }
3663 }
3664
3665 /**
3666 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3667 * argument which specifies the endianness of the value as stored in memory.
3668 * @param o Java heap object in which the value resides
3669 * @param offset The offset in bytes from the start of the object
3670 * @param x the value to store
3671 * @param bigEndian The endianness of the value
3672 * @throws RuntimeException No defined exceptions are thrown, not even
3673 * {@link NullPointerException}
3674 * @since 9
3675 */
3676 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3677 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3678 }
3679
3680 /** @see #putLongUnaligned(Object, long, long) */
3681 @IntrinsicCandidate
3682 public final void putIntUnaligned(Object o, long offset, int x) {
3683 if ((offset & 3) == 0) {
3684 putInt(o, offset, x);
3685 } else if ((offset & 1) == 0) {
3686 putIntParts(o, offset,
3687 (short)(x >> 0),
3688 (short)(x >>> 16));
3689 } else {
3690 putIntParts(o, offset,
3691 (byte)(x >>> 0),
3692 (byte)(x >>> 8),
3693 (byte)(x >>> 16),
3694 (byte)(x >>> 24));
3695 }
3696 }
3697 /** @see #putLongUnaligned(Object, long, long, boolean) */
3698 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3699 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3700 }
3701
3702 /** @see #putLongUnaligned(Object, long, long) */
3703 @IntrinsicCandidate
3704 public final void putShortUnaligned(Object o, long offset, short x) {
3705 if ((offset & 1) == 0) {
3706 putShort(o, offset, x);
3707 } else {
3708 putShortParts(o, offset,
3709 (byte)(x >>> 0),
3710 (byte)(x >>> 8));
3711 }
3712 }
3713 /** @see #putLongUnaligned(Object, long, long, boolean) */
3714 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3715 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3716 }
3717
3718 /** @see #putLongUnaligned(Object, long, long) */
3719 @IntrinsicCandidate
3720 public final void putCharUnaligned(Object o, long offset, char x) {
3721 putShortUnaligned(o, offset, (short)x);
3722 }
3723 /** @see #putLongUnaligned(Object, long, long, boolean) */
3724 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3725 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3726 }
3727
3728 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
3729
3730 // These methods construct integers from bytes. The byte ordering
3731 // is the native endianness of this platform.
3732 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3733 return ((toUnsignedLong(i0) << pickPos(56, 0))
3734 | (toUnsignedLong(i1) << pickPos(56, 8))
3735 | (toUnsignedLong(i2) << pickPos(56, 16))
3736 | (toUnsignedLong(i3) << pickPos(56, 24))
3737 | (toUnsignedLong(i4) << pickPos(56, 32))
3738 | (toUnsignedLong(i5) << pickPos(56, 40))
3739 | (toUnsignedLong(i6) << pickPos(56, 48))
3740 | (toUnsignedLong(i7) << pickPos(56, 56)));
3741 }
3742 private static long makeLong(short i0, short i1, short i2, short i3) {
3743 return ((toUnsignedLong(i0) << pickPos(48, 0))
3744 | (toUnsignedLong(i1) << pickPos(48, 16))
3745 | (toUnsignedLong(i2) << pickPos(48, 32))
3746 | (toUnsignedLong(i3) << pickPos(48, 48)));
3747 }
3748 private static long makeLong(int i0, int i1) {
3749 return (toUnsignedLong(i0) << pickPos(32, 0))
3750 | (toUnsignedLong(i1) << pickPos(32, 32));
3751 }
3752 private static int makeInt(short i0, short i1) {
3753 return (toUnsignedInt(i0) << pickPos(16, 0))
3754 | (toUnsignedInt(i1) << pickPos(16, 16));
3755 }
3756 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3757 return ((toUnsignedInt(i0) << pickPos(24, 0))
3758 | (toUnsignedInt(i1) << pickPos(24, 8))
3759 | (toUnsignedInt(i2) << pickPos(24, 16))
3760 | (toUnsignedInt(i3) << pickPos(24, 24)));
3761 }
3762 private static short makeShort(byte i0, byte i1) {
3763 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3764 | (toUnsignedInt(i1) << pickPos(8, 8)));
3765 }
3766
3767 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
3768 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
3769 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
3770
3771 // These methods write integers to memory from smaller parts
3772 // provided by their caller. The ordering in which these parts
3773 // are written is the native endianness of this platform.
3774 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3775 putByte(o, offset + 0, pick(i0, i7));
3776 putByte(o, offset + 1, pick(i1, i6));
3777 putByte(o, offset + 2, pick(i2, i5));
3778 putByte(o, offset + 3, pick(i3, i4));
3779 putByte(o, offset + 4, pick(i4, i3));
3780 putByte(o, offset + 5, pick(i5, i2));
3781 putByte(o, offset + 6, pick(i6, i1));
3782 putByte(o, offset + 7, pick(i7, i0));
3783 }
3784 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3785 putShort(o, offset + 0, pick(i0, i3));
3786 putShort(o, offset + 2, pick(i1, i2));
3787 putShort(o, offset + 4, pick(i2, i1));
3788 putShort(o, offset + 6, pick(i3, i0));
3789 }
3790 private void putLongParts(Object o, long offset, int i0, int i1) {
3791 putInt(o, offset + 0, pick(i0, i1));
3792 putInt(o, offset + 4, pick(i1, i0));
3793 }
3794 private void putIntParts(Object o, long offset, short i0, short i1) {
3795 putShort(o, offset + 0, pick(i0, i1));
3796 putShort(o, offset + 2, pick(i1, i0));
3797 }
3798 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3799 putByte(o, offset + 0, pick(i0, i3));
3800 putByte(o, offset + 1, pick(i1, i2));
3801 putByte(o, offset + 2, pick(i2, i1));
3802 putByte(o, offset + 3, pick(i3, i0));
3803 }
3804 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3805 putByte(o, offset + 0, pick(i0, i1));
3806 putByte(o, offset + 1, pick(i1, i0));
3807 }
3808
3809 // Zero-extend an integer
3810 private static int toUnsignedInt(byte n) { return n & 0xff; }
3811 private static int toUnsignedInt(short n) { return n & 0xffff; }
3812 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3813 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3814 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3815
3816 // Maybe byte-reverse an integer
3817 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
3818 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
3819 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
3820 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
3821
3822
3823
3824 private native long allocateMemory0(long bytes);
3825 private native long reallocateMemory0(long address, long bytes);
3826 private native void freeMemory0(long address);
3827 @IntrinsicCandidate
3828 private native void setMemory0(Object o, long offset, long bytes, byte value);
3829 @IntrinsicCandidate
3830 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3831 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3832 private native long objectFieldOffset0(Field f);
3833 private native long objectFieldOffset1(Class<?> c, String name);
3834 private native long staticFieldOffset0(Field f);
3835 private native Object staticFieldBase0(Field f);
3836 private native boolean shouldBeInitialized0(Class<?> c);
3837 private native void ensureClassInitialized0(Class<?> c);
3838 private native int arrayBaseOffset0(Class<?> arrayClass);
3839 private native int arrayIndexScale0(Class<?> arrayClass);
3840 private native int getLoadAverage0(double[] loadavg, int nelems);
3841
3842
3843 /**
3844 * Invokes the given direct byte buffer's cleaner, if any.
3845 *
3846 * @param directBuffer a direct byte buffer
3847 * @throws NullPointerException if {@code directBuffer} is null
3848 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
3849 * or is a {@link java.nio.Buffer#slice slice}, or is a
3850 * {@link java.nio.Buffer#duplicate duplicate}
3851 */
3852 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
3853 if (!directBuffer.isDirect())
3854 throw new IllegalArgumentException("buffer is non-direct");
3855
3856 DirectBuffer db = (DirectBuffer) directBuffer;
3857 if (db.attachment() != null)
3858 throw new IllegalArgumentException("duplicate or slice");
3859
3860 Cleaner cleaner = db.cleaner();
3861 if (cleaner != null) {
3862 cleaner.clean();
3863 }
3864 }
3865 }