1 /*
2 * Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.misc;
27
28 import jdk.internal.HotSpotIntrinsicCandidate;
29 import jdk.internal.ref.Cleaner;
30 import jdk.internal.vm.annotation.ForceInline;
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 resposibility 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 @HotSpotIntrinsicCandidate
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 @HotSpotIntrinsicCandidate
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 @HotSpotIntrinsicCandidate
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 @HotSpotIntrinsicCandidate
198 public native void putReference(Object o, long offset, Object x);
199
200 /** @see #getInt(Object, long) */
201 @HotSpotIntrinsicCandidate
202 public native boolean getBoolean(Object o, long offset);
203
204 /** @see #putInt(Object, long, int) */
205 @HotSpotIntrinsicCandidate
206 public native void putBoolean(Object o, long offset, boolean x);
207
208 /** @see #getInt(Object, long) */
209 @HotSpotIntrinsicCandidate
210 public native byte getByte(Object o, long offset);
211
212 /** @see #putInt(Object, long, int) */
213 @HotSpotIntrinsicCandidate
214 public native void putByte(Object o, long offset, byte x);
215
216 /** @see #getInt(Object, long) */
217 @HotSpotIntrinsicCandidate
218 public native short getShort(Object o, long offset);
219
220 /** @see #putInt(Object, long, int) */
221 @HotSpotIntrinsicCandidate
222 public native void putShort(Object o, long offset, short x);
223
224 /** @see #getInt(Object, long) */
225 @HotSpotIntrinsicCandidate
226 public native char getChar(Object o, long offset);
227
228 /** @see #putInt(Object, long, int) */
229 @HotSpotIntrinsicCandidate
230 public native void putChar(Object o, long offset, char x);
231
232 /** @see #getInt(Object, long) */
233 @HotSpotIntrinsicCandidate
234 public native long getLong(Object o, long offset);
235
236 /** @see #putInt(Object, long, int) */
237 @HotSpotIntrinsicCandidate
238 public native void putLong(Object o, long offset, long x);
239
240 /** @see #getInt(Object, long) */
241 @HotSpotIntrinsicCandidate
242 public native float getFloat(Object o, long offset);
243
244 /** @see #putInt(Object, long, int) */
245 @HotSpotIntrinsicCandidate
246 public native void putFloat(Object o, long offset, float x);
247
248 /** @see #getInt(Object, long) */
249 @HotSpotIntrinsicCandidate
250 public native double getDouble(Object o, long offset);
251
252 /** @see #putInt(Object, long, int) */
253 @HotSpotIntrinsicCandidate
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 resposibility of the caller to make
429 * sure arguments are checked before the methods are called. While
430 * some rudimentary checks are performed on the input, the checks
431 * are best effort and when performance is an overriding priority,
432 * as when methods of this class are optimized by the runtime
433 * compiler, some or all checks (if any) may be elided. Hence, the
434 * caller must not rely on the checks and corresponding
435 * exceptions!
436 *
437 * @return an exception object
438 */
439 private RuntimeException invalidInput() {
440 return new IllegalArgumentException();
441 }
442
443 /**
444 * Check if a value is 32-bit clean (32 MSB are all zero)
445 *
446 * @param value the 64-bit value to check
447 *
448 * @return true if the value is 32-bit clean
449 */
450 private boolean is32BitClean(long value) {
451 return value >>> 32 == 0;
452 }
453
454 /**
455 * Check the validity of a size (the equivalent of a size_t)
456 *
457 * @throws RuntimeException if the size is invalid
458 * (<em>Note:</em> after optimization, invalid inputs may
459 * go undetected, which will lead to unpredictable
460 * behavior)
461 */
462 private void checkSize(long size) {
463 if (ADDRESS_SIZE == 4) {
464 // Note: this will also check for negative sizes
465 if (!is32BitClean(size)) {
466 throw invalidInput();
467 }
468 } else if (size < 0) {
469 throw invalidInput();
470 }
471 }
472
473 /**
474 * Check the validity of a native address (the equivalent of void*)
475 *
476 * @throws RuntimeException if the address is invalid
477 * (<em>Note:</em> after optimization, invalid inputs may
478 * go undetected, which will lead to unpredictable
479 * behavior)
480 */
481 private void checkNativeAddress(long address) {
482 if (ADDRESS_SIZE == 4) {
483 // Accept both zero and sign extended pointers. A valid
484 // pointer will, after the +1 below, either have produced
485 // the value 0x0 or 0x1. Masking off the low bit allows
486 // for testing against 0.
487 if ((((address >> 32) + 1) & ~1) != 0) {
488 throw invalidInput();
489 }
490 }
491 }
492
493 /**
494 * Check the validity of an offset, relative to a base object
495 *
496 * @param o the base object
497 * @param offset the offset to check
498 *
499 * @throws RuntimeException if the size is invalid
500 * (<em>Note:</em> after optimization, invalid inputs may
501 * go undetected, which will lead to unpredictable
502 * behavior)
503 */
504 private void checkOffset(Object o, long offset) {
505 if (ADDRESS_SIZE == 4) {
506 // Note: this will also check for negative offsets
507 if (!is32BitClean(offset)) {
508 throw invalidInput();
509 }
510 } else if (offset < 0) {
511 throw invalidInput();
512 }
513 }
514
515 /**
516 * Check the validity of a double-register pointer
517 *
518 * Note: This code deliberately does *not* check for NPE for (at
519 * least) three reasons:
520 *
521 * 1) NPE is not just NULL/0 - there is a range of values all
522 * resulting in an NPE, which is not trivial to check for
523 *
524 * 2) It is the responsibility of the callers of Unsafe methods
525 * to verify the input, so throwing an exception here is not really
526 * useful - passing in a NULL pointer is a critical error and the
527 * must not expect an exception to be thrown anyway.
528 *
529 * 3) the actual operations will detect NULL pointers anyway by
530 * means of traps and signals (like SIGSEGV).
531 *
532 * @param o Java heap object, or null
533 * @param offset indication of where the variable resides in a Java heap
534 * object, if any, else a memory address locating the variable
535 * statically
536 *
537 * @throws RuntimeException if the pointer is invalid
538 * (<em>Note:</em> after optimization, invalid inputs may
539 * go undetected, which will lead to unpredictable
540 * behavior)
541 */
542 private void checkPointer(Object o, long offset) {
543 if (o == null) {
544 checkNativeAddress(offset);
545 } else {
546 checkOffset(o, offset);
547 }
548 }
549
550 /**
551 * Check if a type is a primitive array type
552 *
553 * @param c the type to check
554 *
555 * @return true if the type is a primitive array type
556 */
557 private void checkPrimitiveArray(Class<?> c) {
558 Class<?> componentType = c.getComponentType();
559 if (componentType == null || !componentType.isPrimitive()) {
560 throw invalidInput();
561 }
562 }
563
564 /**
565 * Check that a pointer is a valid primitive array type pointer
566 *
567 * Note: pointers off-heap are considered to be primitive arrays
568 *
569 * @throws RuntimeException if the pointer is invalid
570 * (<em>Note:</em> after optimization, invalid inputs may
571 * go undetected, which will lead to unpredictable
572 * behavior)
573 */
574 private void checkPrimitivePointer(Object o, long offset) {
575 checkPointer(o, offset);
576
577 if (o != null) {
578 // If on heap, it must be a primitive array
579 checkPrimitiveArray(o.getClass());
580 }
581 }
582
583
584 /// wrappers for malloc, realloc, free:
585
586 /**
587 * Round up allocation size to a multiple of HeapWordSize.
588 */
589 private long alignToHeapWordSize(long bytes) {
590 if (bytes >= 0) {
591 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
592 } else {
593 throw invalidInput();
594 }
595 }
596
597 /**
598 * Allocates a new block of native memory, of the given size in bytes. The
599 * contents of the memory are uninitialized; they will generally be
600 * garbage. The resulting native pointer will never be zero, and will be
601 * aligned for all value types. Dispose of this memory by calling {@link
602 * #freeMemory}, or resize it with {@link #reallocateMemory}.
603 *
604 * <em>Note:</em> It is the resposibility of the caller to make
605 * sure arguments are checked before the methods are called. While
606 * some rudimentary checks are performed on the input, the checks
607 * are best effort and when performance is an overriding priority,
608 * as when methods of this class are optimized by the runtime
609 * compiler, some or all checks (if any) may be elided. Hence, the
610 * caller must not rely on the checks and corresponding
611 * exceptions!
612 *
613 * @throws RuntimeException if the size is negative or too large
614 * for the native size_t type
615 *
616 * @throws OutOfMemoryError if the allocation is refused by the system
617 *
618 * @see #getByte(long)
619 * @see #putByte(long, byte)
620 */
621 public long allocateMemory(long bytes) {
622 bytes = alignToHeapWordSize(bytes);
623
624 allocateMemoryChecks(bytes);
625
626 if (bytes == 0) {
627 return 0;
628 }
629
630 long p = allocateMemory0(bytes);
631 if (p == 0) {
632 throw new OutOfMemoryError();
633 }
634
635 return p;
636 }
637
638 /**
639 * Validate the arguments to allocateMemory
640 *
641 * @throws RuntimeException if the arguments are invalid
642 * (<em>Note:</em> after optimization, invalid inputs may
643 * go undetected, which will lead to unpredictable
644 * behavior)
645 */
646 private void allocateMemoryChecks(long bytes) {
647 checkSize(bytes);
648 }
649
650 /**
651 * Resizes a new block of native memory, to the given size in bytes. The
652 * contents of the new block past the size of the old block are
653 * uninitialized; they will generally be garbage. The resulting native
654 * pointer will be zero if and only if the requested size is zero. The
655 * resulting native pointer will be aligned for all value types. Dispose
656 * of this memory by calling {@link #freeMemory}, or resize it with {@link
657 * #reallocateMemory}. The address passed to this method may be null, in
658 * which case an allocation will be performed.
659 *
660 * <em>Note:</em> It is the resposibility of the caller to make
661 * sure arguments are checked before the methods are called. While
662 * some rudimentary checks are performed on the input, the checks
663 * are best effort and when performance is an overriding priority,
664 * as when methods of this class are optimized by the runtime
665 * compiler, some or all checks (if any) may be elided. Hence, the
666 * caller must not rely on the checks and corresponding
667 * exceptions!
668 *
669 * @throws RuntimeException if the size is negative or too large
670 * for the native size_t type
671 *
672 * @throws OutOfMemoryError if the allocation is refused by the system
673 *
674 * @see #allocateMemory
675 */
676 public long reallocateMemory(long address, long bytes) {
677 bytes = alignToHeapWordSize(bytes);
678
679 reallocateMemoryChecks(address, bytes);
680
681 if (bytes == 0) {
682 freeMemory(address);
683 return 0;
684 }
685
686 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
687 if (p == 0) {
688 throw new OutOfMemoryError();
689 }
690
691 return p;
692 }
693
694 /**
695 * Validate the arguments to reallocateMemory
696 *
697 * @throws RuntimeException if the arguments are invalid
698 * (<em>Note:</em> after optimization, invalid inputs may
699 * go undetected, which will lead to unpredictable
700 * behavior)
701 */
702 private void reallocateMemoryChecks(long address, long bytes) {
703 checkPointer(null, address);
704 checkSize(bytes);
705 }
706
707 /**
708 * Sets all bytes in a given block of memory to a fixed value
709 * (usually zero).
710 *
711 * <p>This method determines a block's base address by means of two parameters,
712 * and so it provides (in effect) a <em>double-register</em> addressing mode,
713 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
714 * the offset supplies an absolute base address.
715 *
716 * <p>The stores are in coherent (atomic) units of a size determined
717 * by the address and length parameters. If the effective address and
718 * length are all even modulo 8, the stores take place in 'long' units.
719 * If the effective address and length are (resp.) even modulo 4 or 2,
720 * the stores take place in units of 'int' or 'short'.
721 *
722 * <em>Note:</em> It is the resposibility of the caller to make
723 * sure arguments are checked before the methods are called. While
724 * some rudimentary checks are performed on the input, the checks
725 * are best effort and when performance is an overriding priority,
726 * as when methods of this class are optimized by the runtime
727 * compiler, some or all checks (if any) may be elided. Hence, the
728 * caller must not rely on the checks and corresponding
729 * exceptions!
730 *
731 * @throws RuntimeException if any of the arguments is invalid
732 *
733 * @since 1.7
734 */
735 public void setMemory(Object o, long offset, long bytes, byte value) {
736 setMemoryChecks(o, offset, bytes, value);
737
738 if (bytes == 0) {
739 return;
740 }
741
742 setMemory0(o, offset, bytes, value);
743 }
744
745 /**
746 * Sets all bytes in a given block of memory to a fixed value
747 * (usually zero). This provides a <em>single-register</em> addressing mode,
748 * as discussed in {@link #getInt(Object,long)}.
749 *
750 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
751 */
752 public void setMemory(long address, long bytes, byte value) {
753 setMemory(null, address, bytes, value);
754 }
755
756 /**
757 * Validate the arguments to setMemory
758 *
759 * @throws RuntimeException if the arguments are invalid
760 * (<em>Note:</em> after optimization, invalid inputs may
761 * go undetected, which will lead to unpredictable
762 * behavior)
763 */
764 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
765 checkPrimitivePointer(o, offset);
766 checkSize(bytes);
767 }
768
769 /**
770 * Sets all bytes in a given block of memory to a copy of another
771 * block.
772 *
773 * <p>This method determines each block's base address by means of two parameters,
774 * and so it provides (in effect) a <em>double-register</em> addressing mode,
775 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
776 * the offset supplies an absolute base address.
777 *
778 * <p>The transfers are in coherent (atomic) units of a size determined
779 * by the address and length parameters. If the effective addresses and
780 * length are all even modulo 8, the transfer takes place in 'long' units.
781 * If the effective addresses and length are (resp.) even modulo 4 or 2,
782 * the transfer takes place in units of 'int' or 'short'.
783 *
784 * <em>Note:</em> It is the resposibility of the caller to make
785 * sure arguments are checked before the methods are called. While
786 * some rudimentary checks are performed on the input, the checks
787 * are best effort and when performance is an overriding priority,
788 * as when methods of this class are optimized by the runtime
789 * compiler, some or all checks (if any) may be elided. Hence, the
790 * caller must not rely on the checks and corresponding
791 * exceptions!
792 *
793 * @throws RuntimeException if any of the arguments is invalid
794 *
795 * @since 1.7
796 */
797 public void copyMemory(Object srcBase, long srcOffset,
798 Object destBase, long destOffset,
799 long bytes) {
800 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
801
802 if (bytes == 0) {
803 return;
804 }
805
806 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
807 }
808
809 /**
810 * Sets all bytes in a given block of memory to a copy of another
811 * block. This provides a <em>single-register</em> addressing mode,
812 * as discussed in {@link #getInt(Object,long)}.
813 *
814 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
815 */
816 public void copyMemory(long srcAddress, long destAddress, long bytes) {
817 copyMemory(null, srcAddress, null, destAddress, bytes);
818 }
819
820 /**
821 * Validate the arguments to copyMemory
822 *
823 * @throws RuntimeException if any of the arguments is invalid
824 * (<em>Note:</em> after optimization, invalid inputs may
825 * go undetected, which will lead to unpredictable
826 * behavior)
827 */
828 private void copyMemoryChecks(Object srcBase, long srcOffset,
829 Object destBase, long destOffset,
830 long bytes) {
831 checkSize(bytes);
832 checkPrimitivePointer(srcBase, srcOffset);
833 checkPrimitivePointer(destBase, destOffset);
834 }
835
836 /**
837 * Copies all elements from one block of memory to another block,
838 * *unconditionally* byte swapping the elements on the fly.
839 *
840 * <p>This method determines each block's base address by means of two parameters,
841 * and so it provides (in effect) a <em>double-register</em> addressing mode,
842 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
843 * the offset supplies an absolute base address.
844 *
845 * <em>Note:</em> It is the resposibility of the caller to make
846 * sure arguments are checked before the methods are called. While
847 * some rudimentary checks are performed on the input, the checks
848 * are best effort and when performance is an overriding priority,
849 * as when methods of this class are optimized by the runtime
850 * compiler, some or all checks (if any) may be elided. Hence, the
851 * caller must not rely on the checks and corresponding
852 * exceptions!
853 *
854 * @throws RuntimeException if any of the arguments is invalid
855 *
856 * @since 9
857 */
858 public void copySwapMemory(Object srcBase, long srcOffset,
859 Object destBase, long destOffset,
860 long bytes, long elemSize) {
861 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
862
863 if (bytes == 0) {
864 return;
865 }
866
867 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
868 }
869
870 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
871 Object destBase, long destOffset,
872 long bytes, long elemSize) {
873 checkSize(bytes);
874
875 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
876 throw invalidInput();
877 }
878 if (bytes % elemSize != 0) {
879 throw invalidInput();
880 }
881
882 checkPrimitivePointer(srcBase, srcOffset);
883 checkPrimitivePointer(destBase, destOffset);
884 }
885
886 /**
887 * Copies all elements from one block of memory to another block, byte swapping the
888 * elements on the fly.
889 *
890 * This provides a <em>single-register</em> addressing mode, as
891 * discussed in {@link #getInt(Object,long)}.
892 *
893 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
894 */
895 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
896 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
897 }
898
899 /**
900 * Disposes of a block of native memory, as obtained from {@link
901 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
902 * this method may be null, in which case no action is taken.
903 *
904 * <em>Note:</em> It is the resposibility of the caller to make
905 * sure arguments are checked before the methods are called. While
906 * some rudimentary checks are performed on the input, the checks
907 * are best effort and when performance is an overriding priority,
908 * as when methods of this class are optimized by the runtime
909 * compiler, some or all checks (if any) may be elided. Hence, the
910 * caller must not rely on the checks and corresponding
911 * exceptions!
912 *
913 * @throws RuntimeException if any of the arguments is invalid
914 *
915 * @see #allocateMemory
916 */
917 public void freeMemory(long address) {
918 freeMemoryChecks(address);
919
920 if (address == 0) {
921 return;
922 }
923
924 freeMemory0(address);
925 }
926
927 /**
928 * Validate the arguments to freeMemory
929 *
930 * @throws RuntimeException if the arguments are invalid
931 * (<em>Note:</em> after optimization, invalid inputs may
932 * go undetected, which will lead to unpredictable
933 * behavior)
934 */
935 private void freeMemoryChecks(long address) {
936 checkPointer(null, address);
937 }
938
939 /**
940 * Ensure writeback of a specified virtual memory address range
941 * from cache to physical memory. All bytes in the address range
942 * are guaranteed to have been written back to physical memory on
943 * return from this call i.e. subsequently executed store
944 * instructions are guaranteed not to be visible before the
945 * writeback is completed.
946 *
947 * @param address
948 * the lowest byte address that must be guaranteed written
949 * back to memory. bytes at lower addresses may also be
950 * written back.
951 *
952 * @param length
953 * the length in bytes of the region starting at address
954 * that must be guaranteed written back to memory.
955 *
956 * @throws RuntimeException if memory writeback is not supported
957 * on the current hardware of if the arguments are invalid.
958 * (<em>Note:</em> after optimization, invalid inputs may
959 * go undetected, which will lead to unpredictable
960 * behavior)
961 *
962 * @since 14
963 */
964
965 public void writebackMemory(long address, long length) {
966 checkWritebackEnabled();
967 checkWritebackMemory(address, length);
968
969 // perform any required pre-writeback barrier
970 writebackPreSync0();
971
972 // write back one cache line at a time
973 long line = dataCacheLineAlignDown(address);
974 long end = address + length;
975 while (line < end) {
976 writeback0(line);
977 line += dataCacheLineFlushSize();
978 }
979
980 // perform any required post-writeback barrier
981 writebackPostSync0();
982 }
983
984 /**
985 * Validate the arguments to writebackMemory
986 *
987 * @throws RuntimeException if the arguments are invalid
988 * (<em>Note:</em> after optimization, invalid inputs may
989 * go undetected, which will lead to unpredictable
990 * behavior)
991 */
992 private void checkWritebackMemory(long address, long length) {
993 checkNativeAddress(address);
994 checkSize(length);
995 }
996
997 /**
998 * Validate that the current hardware supports memory writeback.
999 * (<em>Note:</em> this is a belt and braces check. Clients are
1000 * expected to test whether writeback is enabled by calling
1001 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1002 * calling method {@link writeback #writeback} if it is disabled).
1003 *
1004 *
1005 * @throws RuntimeException if memory writeback is not supported
1006 */
1007 private void checkWritebackEnabled() {
1008 if (!isWritebackEnabled()) {
1009 throw new RuntimeException("writebackMemory not enabled!");
1010 }
1011 }
1012
1013 /**
1014 * force writeback of an individual cache line.
1015 *
1016 * @param address
1017 * the start address of the cache line to be written back
1018 */
1019 @HotSpotIntrinsicCandidate
1020 private native void writeback0(long address);
1021
1022 /**
1023 * Serialize writeback operations relative to preceding memory writes.
1024 */
1025 @HotSpotIntrinsicCandidate
1026 private native void writebackPreSync0();
1027
1028 /**
1029 * Serialize writeback operations relative to following memory writes.
1030 */
1031 @HotSpotIntrinsicCandidate
1032 private native void writebackPostSync0();
1033
1034 /// random queries
1035
1036 /**
1037 * This constant differs from all results that will ever be returned from
1038 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1039 * or {@link #arrayBaseOffset}.
1040 */
1041 public static final int INVALID_FIELD_OFFSET = -1;
1042
1043 /**
1044 * Reports the location of a given field in the storage allocation of its
1045 * class. Do not expect to perform any sort of arithmetic on this offset;
1046 * it is just a cookie which is passed to the unsafe heap memory accessors.
1047 *
1048 * <p>Any given field will always have the same offset and base, and no
1049 * two distinct fields of the same class will ever have the same offset
1050 * and base.
1051 *
1052 * <p>As of 1.4.1, offsets for fields are represented as long values,
1053 * although the Sun JVM does not use the most significant 32 bits.
1054 * However, JVM implementations which store static fields at absolute
1055 * addresses can use long offsets and null base pointers to express
1056 * the field locations in a form usable by {@link #getInt(Object,long)}.
1057 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1058 * must preserve all bits of static field offsets.
1059 * @see #getInt(Object, long)
1060 */
1061 public long objectFieldOffset(Field f) {
1062 if (f == null) {
1063 throw new NullPointerException();
1064 }
1065
1066 return objectFieldOffset0(f);
1067 }
1068
1069 /**
1070 * Reports the location of the field with a given name in the storage
1071 * allocation of its class.
1072 *
1073 * @throws NullPointerException if any parameter is {@code null}.
1074 * @throws InternalError if there is no field named {@code name} declared
1075 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1076 * would throw {@code java.lang.NoSuchFieldException}.
1077 *
1078 * @see #objectFieldOffset(Field)
1079 */
1080 public long objectFieldOffset(Class<?> c, String name) {
1081 if (c == null || name == null) {
1082 throw new NullPointerException();
1083 }
1084
1085 return objectFieldOffset1(c, name);
1086 }
1087
1088 /**
1089 * Reports the location of a given static field, in conjunction with {@link
1090 * #staticFieldBase}.
1091 * <p>Do not expect to perform any sort of arithmetic on this offset;
1092 * it is just a cookie which is passed to the unsafe heap memory accessors.
1093 *
1094 * <p>Any given field will always have the same offset, and no two distinct
1095 * fields of the same class will ever have the same offset.
1096 *
1097 * <p>As of 1.4.1, offsets for fields are represented as long values,
1098 * although the Sun JVM does not use the most significant 32 bits.
1099 * It is hard to imagine a JVM technology which needs more than
1100 * a few bits to encode an offset within a non-array object,
1101 * However, for consistency with other methods in this class,
1102 * this method reports its result as a long value.
1103 * @see #getInt(Object, long)
1104 */
1105 public long staticFieldOffset(Field f) {
1106 if (f == null) {
1107 throw new NullPointerException();
1108 }
1109
1110 return staticFieldOffset0(f);
1111 }
1112
1113 /**
1114 * Reports the location of a given static field, in conjunction with {@link
1115 * #staticFieldOffset}.
1116 * <p>Fetch the base "Object", if any, with which static fields of the
1117 * given class can be accessed via methods like {@link #getInt(Object,
1118 * long)}. This value may be null. This value may refer to an object
1119 * which is a "cookie", not guaranteed to be a real Object, and it should
1120 * not be used in any way except as argument to the get and put routines in
1121 * this class.
1122 */
1123 public Object staticFieldBase(Field f) {
1124 if (f == null) {
1125 throw new NullPointerException();
1126 }
1127
1128 return staticFieldBase0(f);
1129 }
1130
1131 /**
1132 * Detects if the given class may need to be initialized. This is often
1133 * needed in conjunction with obtaining the static field base of a
1134 * class.
1135 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1136 */
1137 public boolean shouldBeInitialized(Class<?> c) {
1138 if (c == null) {
1139 throw new NullPointerException();
1140 }
1141
1142 return shouldBeInitialized0(c);
1143 }
1144
1145 /**
1146 * Ensures the given class has been initialized. This is often
1147 * needed in conjunction with obtaining the static field base of a
1148 * class.
1149 */
1150 public void ensureClassInitialized(Class<?> c) {
1151 if (c == null) {
1152 throw new NullPointerException();
1153 }
1154
1155 ensureClassInitialized0(c);
1156 }
1157
1158 /**
1159 * Reports the offset of the first element in the storage allocation of a
1160 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1161 * for the same class, you may use that scale factor, together with this
1162 * base offset, to form new offsets to access elements of arrays of the
1163 * given class.
1164 *
1165 * @see #getInt(Object, long)
1166 * @see #putInt(Object, long, int)
1167 */
1168 public int arrayBaseOffset(Class<?> arrayClass) {
1169 if (arrayClass == null) {
1170 throw new NullPointerException();
1171 }
1172
1173 return arrayBaseOffset0(arrayClass);
1174 }
1175
1176
1177 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1178 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1179 = theUnsafe.arrayBaseOffset(boolean[].class);
1180
1181 /** The value of {@code arrayBaseOffset(byte[].class)} */
1182 public static final int ARRAY_BYTE_BASE_OFFSET
1183 = theUnsafe.arrayBaseOffset(byte[].class);
1184
1185 /** The value of {@code arrayBaseOffset(short[].class)} */
1186 public static final int ARRAY_SHORT_BASE_OFFSET
1187 = theUnsafe.arrayBaseOffset(short[].class);
1188
1189 /** The value of {@code arrayBaseOffset(char[].class)} */
1190 public static final int ARRAY_CHAR_BASE_OFFSET
1191 = theUnsafe.arrayBaseOffset(char[].class);
1192
1193 /** The value of {@code arrayBaseOffset(int[].class)} */
1194 public static final int ARRAY_INT_BASE_OFFSET
1195 = theUnsafe.arrayBaseOffset(int[].class);
1196
1197 /** The value of {@code arrayBaseOffset(long[].class)} */
1198 public static final int ARRAY_LONG_BASE_OFFSET
1199 = theUnsafe.arrayBaseOffset(long[].class);
1200
1201 /** The value of {@code arrayBaseOffset(float[].class)} */
1202 public static final int ARRAY_FLOAT_BASE_OFFSET
1203 = theUnsafe.arrayBaseOffset(float[].class);
1204
1205 /** The value of {@code arrayBaseOffset(double[].class)} */
1206 public static final int ARRAY_DOUBLE_BASE_OFFSET
1207 = theUnsafe.arrayBaseOffset(double[].class);
1208
1209 /** The value of {@code arrayBaseOffset(Object[].class)} */
1210 public static final int ARRAY_OBJECT_BASE_OFFSET
1211 = theUnsafe.arrayBaseOffset(Object[].class);
1212
1213 /**
1214 * Reports the scale factor for addressing elements in the storage
1215 * allocation of a given array class. However, arrays of "narrow" types
1216 * will generally not work properly with accessors like {@link
1217 * #getByte(Object, long)}, so the scale factor for such classes is reported
1218 * as zero.
1219 *
1220 * @see #arrayBaseOffset
1221 * @see #getInt(Object, long)
1222 * @see #putInt(Object, long, int)
1223 */
1224 public int arrayIndexScale(Class<?> arrayClass) {
1225 if (arrayClass == null) {
1226 throw new NullPointerException();
1227 }
1228
1229 return arrayIndexScale0(arrayClass);
1230 }
1231
1232
1233 /** The value of {@code arrayIndexScale(boolean[].class)} */
1234 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1235 = theUnsafe.arrayIndexScale(boolean[].class);
1236
1237 /** The value of {@code arrayIndexScale(byte[].class)} */
1238 public static final int ARRAY_BYTE_INDEX_SCALE
1239 = theUnsafe.arrayIndexScale(byte[].class);
1240
1241 /** The value of {@code arrayIndexScale(short[].class)} */
1242 public static final int ARRAY_SHORT_INDEX_SCALE
1243 = theUnsafe.arrayIndexScale(short[].class);
1244
1245 /** The value of {@code arrayIndexScale(char[].class)} */
1246 public static final int ARRAY_CHAR_INDEX_SCALE
1247 = theUnsafe.arrayIndexScale(char[].class);
1248
1249 /** The value of {@code arrayIndexScale(int[].class)} */
1250 public static final int ARRAY_INT_INDEX_SCALE
1251 = theUnsafe.arrayIndexScale(int[].class);
1252
1253 /** The value of {@code arrayIndexScale(long[].class)} */
1254 public static final int ARRAY_LONG_INDEX_SCALE
1255 = theUnsafe.arrayIndexScale(long[].class);
1256
1257 /** The value of {@code arrayIndexScale(float[].class)} */
1258 public static final int ARRAY_FLOAT_INDEX_SCALE
1259 = theUnsafe.arrayIndexScale(float[].class);
1260
1261 /** The value of {@code arrayIndexScale(double[].class)} */
1262 public static final int ARRAY_DOUBLE_INDEX_SCALE
1263 = theUnsafe.arrayIndexScale(double[].class);
1264
1265 /** The value of {@code arrayIndexScale(Object[].class)} */
1266 public static final int ARRAY_OBJECT_INDEX_SCALE
1267 = theUnsafe.arrayIndexScale(Object[].class);
1268
1269 /**
1270 * Reports the size in bytes of a native pointer, as stored via {@link
1271 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1272 * other primitive types (as stored in native memory blocks) is determined
1273 * fully by their information content.
1274 */
1275 public int addressSize() {
1276 return ADDRESS_SIZE;
1277 }
1278
1279 /** The value of {@code addressSize()} */
1280 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1281
1282 /**
1283 * Reports the size in bytes of a native memory page (whatever that is).
1284 * This value will always be a power of two.
1285 */
1286 public int pageSize() { return PAGE_SIZE; }
1287
1288 /**
1289 * Reports the size in bytes of a data cache line written back by
1290 * the hardware cache line flush operation available to the JVM or
1291 * 0 if data cache line flushing is not enabled.
1292 */
1293 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1294
1295 /**
1296 * Rounds down address to a data cache line boundary as
1297 * determined by {@link #dataCacheLineFlushSize}
1298 * @return the rounded down address
1299 */
1300 public long dataCacheLineAlignDown(long address) {
1301 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1302 }
1303
1304 /**
1305 * Returns true if data cache line writeback
1306 */
1307 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1308
1309 /// random trusted operations from JNI:
1310
1311 /**
1312 * Tells the VM to define a class, without security checks. By default, the
1313 * class loader and protection domain come from the caller's class.
1314 */
1315 public Class<?> defineClass(String name, byte[] b, int off, int len,
1316 ClassLoader loader,
1317 ProtectionDomain protectionDomain) {
1318 if (b == null) {
1319 throw new NullPointerException();
1320 }
1321 if (len < 0) {
1322 throw new ArrayIndexOutOfBoundsException();
1323 }
1324
1325 return defineClass0(name, b, off, len, loader, protectionDomain);
1326 }
1327
1328 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1329 ClassLoader loader,
1330 ProtectionDomain protectionDomain);
1331
1332 /**
1333 * Defines a class but does not make it known to the class loader or system dictionary.
1334 * <p>
1335 * For each CP entry, the corresponding CP patch must either be null or have
1336 * the a format that matches its tag:
1337 * <ul>
1338 * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
1339 * <li>Utf8: a string (must have suitable syntax if used as signature or name)
1340 * <li>Class: any java.lang.Class object
1341 * <li>String: any object (not just a java.lang.String)
1342 * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
1343 * </ul>
1344 * @param hostClass context for linkage, access control, protection domain, and class loader
1345 * @param data bytes of a class file
1346 * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
1347 */
1348 public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {
1349 if (hostClass == null || data == null) {
1350 throw new NullPointerException();
1351 }
1352 if (hostClass.isArray() || hostClass.isPrimitive()) {
1353 throw new IllegalArgumentException();
1354 }
1355
1356 return defineAnonymousClass0(hostClass, data, cpPatches);
1357 }
1358
1359 /**
1360 * Allocates an instance but does not run any constructor.
1361 * Initializes the class if it has not yet been.
1362 */
1363 @HotSpotIntrinsicCandidate
1364 public native Object allocateInstance(Class<?> cls)
1365 throws InstantiationException;
1366
1367 /**
1368 * Allocates an array of a given type, but does not do zeroing.
1369 * <p>
1370 * This method should only be used in the very rare cases where a high-performance code
1371 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1372 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1373 * <p>
1374 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1375 * before allowing untrusted code, or code in other threads, to observe the reference
1376 * to the newly allocated array. In addition, the publication of the array reference must be
1377 * safe according to the Java Memory Model requirements.
1378 * <p>
1379 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1380 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1381 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1382 * or issuing a {@link #storeFence} before publishing the reference.
1383 * <p>
1384 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1385 * elements that could break heap integrity.
1386 *
1387 * @param componentType array component type to allocate
1388 * @param length array size to allocate
1389 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1390 * or the length is negative
1391 */
1392 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1393 if (componentType == null) {
1394 throw new IllegalArgumentException("Component type is null");
1395 }
1396 if (!componentType.isPrimitive()) {
1397 throw new IllegalArgumentException("Component type is not primitive");
1398 }
1399 if (length < 0) {
1400 throw new IllegalArgumentException("Negative length");
1401 }
1402 return allocateUninitializedArray0(componentType, length);
1403 }
1404
1405 @HotSpotIntrinsicCandidate
1406 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1407 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1408 // return the zeroed arrays.
1409 if (componentType == byte.class) return new byte[length];
1410 if (componentType == boolean.class) return new boolean[length];
1411 if (componentType == short.class) return new short[length];
1412 if (componentType == char.class) return new char[length];
1413 if (componentType == int.class) return new int[length];
1414 if (componentType == float.class) return new float[length];
1415 if (componentType == long.class) return new long[length];
1416 if (componentType == double.class) return new double[length];
1417 return null;
1418 }
1419
1420 /** Throws the exception without telling the verifier. */
1421 public native void throwException(Throwable ee);
1422
1423 /**
1424 * Atomically updates Java variable to {@code x} if it is currently
1425 * holding {@code expected}.
1426 *
1427 * <p>This operation has memory semantics of a {@code volatile} read
1428 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1429 *
1430 * @return {@code true} if successful
1431 */
1432 @HotSpotIntrinsicCandidate
1433 public final native boolean compareAndSetReference(Object o, long offset,
1434 Object expected,
1435 Object x);
1436
1437 @HotSpotIntrinsicCandidate
1438 public final native Object compareAndExchangeReference(Object o, long offset,
1439 Object expected,
1440 Object x);
1441
1442 @HotSpotIntrinsicCandidate
1443 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1444 Object expected,
1445 Object x) {
1446 return compareAndExchangeReference(o, offset, expected, x);
1447 }
1448
1449 @HotSpotIntrinsicCandidate
1450 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1451 Object expected,
1452 Object x) {
1453 return compareAndExchangeReference(o, offset, expected, x);
1454 }
1455
1456 @HotSpotIntrinsicCandidate
1457 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1458 Object expected,
1459 Object x) {
1460 return compareAndSetReference(o, offset, expected, x);
1461 }
1462
1463 @HotSpotIntrinsicCandidate
1464 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1465 Object expected,
1466 Object x) {
1467 return compareAndSetReference(o, offset, expected, x);
1468 }
1469
1470 @HotSpotIntrinsicCandidate
1471 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1472 Object expected,
1473 Object x) {
1474 return compareAndSetReference(o, offset, expected, x);
1475 }
1476
1477 @HotSpotIntrinsicCandidate
1478 public final boolean weakCompareAndSetReference(Object o, long offset,
1479 Object expected,
1480 Object x) {
1481 return compareAndSetReference(o, offset, expected, x);
1482 }
1483
1484 /**
1485 * Atomically updates Java variable to {@code x} if it is currently
1486 * holding {@code expected}.
1487 *
1488 * <p>This operation has memory semantics of a {@code volatile} read
1489 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1490 *
1491 * @return {@code true} if successful
1492 */
1493 @HotSpotIntrinsicCandidate
1494 public final native boolean compareAndSetInt(Object o, long offset,
1495 int expected,
1496 int x);
1497
1498 @HotSpotIntrinsicCandidate
1499 public final native int compareAndExchangeInt(Object o, long offset,
1500 int expected,
1501 int x);
1502
1503 @HotSpotIntrinsicCandidate
1504 public final int compareAndExchangeIntAcquire(Object o, long offset,
1505 int expected,
1506 int x) {
1507 return compareAndExchangeInt(o, offset, expected, x);
1508 }
1509
1510 @HotSpotIntrinsicCandidate
1511 public final int compareAndExchangeIntRelease(Object o, long offset,
1512 int expected,
1513 int x) {
1514 return compareAndExchangeInt(o, offset, expected, x);
1515 }
1516
1517 @HotSpotIntrinsicCandidate
1518 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1519 int expected,
1520 int x) {
1521 return compareAndSetInt(o, offset, expected, x);
1522 }
1523
1524 @HotSpotIntrinsicCandidate
1525 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1526 int expected,
1527 int x) {
1528 return compareAndSetInt(o, offset, expected, x);
1529 }
1530
1531 @HotSpotIntrinsicCandidate
1532 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1533 int expected,
1534 int x) {
1535 return compareAndSetInt(o, offset, expected, x);
1536 }
1537
1538 @HotSpotIntrinsicCandidate
1539 public final boolean weakCompareAndSetInt(Object o, long offset,
1540 int expected,
1541 int x) {
1542 return compareAndSetInt(o, offset, expected, x);
1543 }
1544
1545 @HotSpotIntrinsicCandidate
1546 public final byte compareAndExchangeByte(Object o, long offset,
1547 byte expected,
1548 byte x) {
1549 long wordOffset = offset & ~3;
1550 int shift = (int) (offset & 3) << 3;
1551 if (BIG_ENDIAN) {
1552 shift = 24 - shift;
1553 }
1554 int mask = 0xFF << shift;
1555 int maskedExpected = (expected & 0xFF) << shift;
1556 int maskedX = (x & 0xFF) << shift;
1557 int fullWord;
1558 do {
1559 fullWord = getIntVolatile(o, wordOffset);
1560 if ((fullWord & mask) != maskedExpected)
1561 return (byte) ((fullWord & mask) >> shift);
1562 } while (!weakCompareAndSetInt(o, wordOffset,
1563 fullWord, (fullWord & ~mask) | maskedX));
1564 return expected;
1565 }
1566
1567 @HotSpotIntrinsicCandidate
1568 public final boolean compareAndSetByte(Object o, long offset,
1569 byte expected,
1570 byte x) {
1571 return compareAndExchangeByte(o, offset, expected, x) == expected;
1572 }
1573
1574 @HotSpotIntrinsicCandidate
1575 public final boolean weakCompareAndSetByte(Object o, long offset,
1576 byte expected,
1577 byte x) {
1578 return compareAndSetByte(o, offset, expected, x);
1579 }
1580
1581 @HotSpotIntrinsicCandidate
1582 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1583 byte expected,
1584 byte x) {
1585 return weakCompareAndSetByte(o, offset, expected, x);
1586 }
1587
1588 @HotSpotIntrinsicCandidate
1589 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1590 byte expected,
1591 byte x) {
1592 return weakCompareAndSetByte(o, offset, expected, x);
1593 }
1594
1595 @HotSpotIntrinsicCandidate
1596 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1597 byte expected,
1598 byte x) {
1599 return weakCompareAndSetByte(o, offset, expected, x);
1600 }
1601
1602 @HotSpotIntrinsicCandidate
1603 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1604 byte expected,
1605 byte x) {
1606 return compareAndExchangeByte(o, offset, expected, x);
1607 }
1608
1609 @HotSpotIntrinsicCandidate
1610 public final byte compareAndExchangeByteRelease(Object o, long offset,
1611 byte expected,
1612 byte x) {
1613 return compareAndExchangeByte(o, offset, expected, x);
1614 }
1615
1616 @HotSpotIntrinsicCandidate
1617 public final short compareAndExchangeShort(Object o, long offset,
1618 short expected,
1619 short x) {
1620 if ((offset & 3) == 3) {
1621 throw new IllegalArgumentException("Update spans the word, not supported");
1622 }
1623 long wordOffset = offset & ~3;
1624 int shift = (int) (offset & 3) << 3;
1625 if (BIG_ENDIAN) {
1626 shift = 16 - shift;
1627 }
1628 int mask = 0xFFFF << shift;
1629 int maskedExpected = (expected & 0xFFFF) << shift;
1630 int maskedX = (x & 0xFFFF) << shift;
1631 int fullWord;
1632 do {
1633 fullWord = getIntVolatile(o, wordOffset);
1634 if ((fullWord & mask) != maskedExpected) {
1635 return (short) ((fullWord & mask) >> shift);
1636 }
1637 } while (!weakCompareAndSetInt(o, wordOffset,
1638 fullWord, (fullWord & ~mask) | maskedX));
1639 return expected;
1640 }
1641
1642 @HotSpotIntrinsicCandidate
1643 public final boolean compareAndSetShort(Object o, long offset,
1644 short expected,
1645 short x) {
1646 return compareAndExchangeShort(o, offset, expected, x) == expected;
1647 }
1648
1649 @HotSpotIntrinsicCandidate
1650 public final boolean weakCompareAndSetShort(Object o, long offset,
1651 short expected,
1652 short x) {
1653 return compareAndSetShort(o, offset, expected, x);
1654 }
1655
1656 @HotSpotIntrinsicCandidate
1657 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1658 short expected,
1659 short x) {
1660 return weakCompareAndSetShort(o, offset, expected, x);
1661 }
1662
1663 @HotSpotIntrinsicCandidate
1664 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1665 short expected,
1666 short x) {
1667 return weakCompareAndSetShort(o, offset, expected, x);
1668 }
1669
1670 @HotSpotIntrinsicCandidate
1671 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1672 short expected,
1673 short x) {
1674 return weakCompareAndSetShort(o, offset, expected, x);
1675 }
1676
1677
1678 @HotSpotIntrinsicCandidate
1679 public final short compareAndExchangeShortAcquire(Object o, long offset,
1680 short expected,
1681 short x) {
1682 return compareAndExchangeShort(o, offset, expected, x);
1683 }
1684
1685 @HotSpotIntrinsicCandidate
1686 public final short compareAndExchangeShortRelease(Object o, long offset,
1687 short expected,
1688 short x) {
1689 return compareAndExchangeShort(o, offset, expected, x);
1690 }
1691
1692 @ForceInline
1693 private char s2c(short s) {
1694 return (char) s;
1695 }
1696
1697 @ForceInline
1698 private short c2s(char s) {
1699 return (short) s;
1700 }
1701
1702 @ForceInline
1703 public final boolean compareAndSetChar(Object o, long offset,
1704 char expected,
1705 char x) {
1706 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1707 }
1708
1709 @ForceInline
1710 public final char compareAndExchangeChar(Object o, long offset,
1711 char expected,
1712 char x) {
1713 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1714 }
1715
1716 @ForceInline
1717 public final char compareAndExchangeCharAcquire(Object o, long offset,
1718 char expected,
1719 char x) {
1720 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1721 }
1722
1723 @ForceInline
1724 public final char compareAndExchangeCharRelease(Object o, long offset,
1725 char expected,
1726 char x) {
1727 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1728 }
1729
1730 @ForceInline
1731 public final boolean weakCompareAndSetChar(Object o, long offset,
1732 char expected,
1733 char x) {
1734 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1735 }
1736
1737 @ForceInline
1738 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1739 char expected,
1740 char x) {
1741 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1742 }
1743
1744 @ForceInline
1745 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1746 char expected,
1747 char x) {
1748 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1749 }
1750
1751 @ForceInline
1752 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1753 char expected,
1754 char x) {
1755 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1756 }
1757
1758 /**
1759 * The JVM converts integral values to boolean values using two
1760 * different conventions, byte testing against zero and truncation
1761 * to least-significant bit.
1762 *
1763 * <p>The JNI documents specify that, at least for returning
1764 * values from native methods, a Java boolean value is converted
1765 * to the value-set 0..1 by first truncating to a byte (0..255 or
1766 * maybe -128..127) and then testing against zero. Thus, Java
1767 * booleans in non-Java data structures are by convention
1768 * represented as 8-bit containers containing either zero (for
1769 * false) or any non-zero value (for true).
1770 *
1771 * <p>Java booleans in the heap are also stored in bytes, but are
1772 * strongly normalized to the value-set 0..1 (i.e., they are
1773 * truncated to the least-significant bit).
1774 *
1775 * <p>The main reason for having different conventions for
1776 * conversion is performance: Truncation to the least-significant
1777 * bit can be usually implemented with fewer (machine)
1778 * instructions than byte testing against zero.
1779 *
1780 * <p>A number of Unsafe methods load boolean values from the heap
1781 * as bytes. Unsafe converts those values according to the JNI
1782 * rules (i.e, using the "testing against zero" convention). The
1783 * method {@code byte2bool} implements that conversion.
1784 *
1785 * @param b the byte to be converted to boolean
1786 * @return the result of the conversion
1787 */
1788 @ForceInline
1789 private boolean byte2bool(byte b) {
1790 return b != 0;
1791 }
1792
1793 /**
1794 * Convert a boolean value to a byte. The return value is strongly
1795 * normalized to the value-set 0..1 (i.e., the value is truncated
1796 * to the least-significant bit). See {@link #byte2bool(byte)} for
1797 * more details on conversion conventions.
1798 *
1799 * @param b the boolean to be converted to byte (and then normalized)
1800 * @return the result of the conversion
1801 */
1802 @ForceInline
1803 private byte bool2byte(boolean b) {
1804 return b ? (byte)1 : (byte)0;
1805 }
1806
1807 @ForceInline
1808 public final boolean compareAndSetBoolean(Object o, long offset,
1809 boolean expected,
1810 boolean x) {
1811 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1812 }
1813
1814 @ForceInline
1815 public final boolean compareAndExchangeBoolean(Object o, long offset,
1816 boolean expected,
1817 boolean x) {
1818 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1819 }
1820
1821 @ForceInline
1822 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1823 boolean expected,
1824 boolean x) {
1825 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1826 }
1827
1828 @ForceInline
1829 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1830 boolean expected,
1831 boolean x) {
1832 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1833 }
1834
1835 @ForceInline
1836 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1837 boolean expected,
1838 boolean x) {
1839 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1840 }
1841
1842 @ForceInline
1843 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1844 boolean expected,
1845 boolean x) {
1846 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1847 }
1848
1849 @ForceInline
1850 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1851 boolean expected,
1852 boolean x) {
1853 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1854 }
1855
1856 @ForceInline
1857 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1858 boolean expected,
1859 boolean x) {
1860 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1861 }
1862
1863 /**
1864 * Atomically updates Java variable to {@code x} if it is currently
1865 * holding {@code expected}.
1866 *
1867 * <p>This operation has memory semantics of a {@code volatile} read
1868 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1869 *
1870 * @return {@code true} if successful
1871 */
1872 @ForceInline
1873 public final boolean compareAndSetFloat(Object o, long offset,
1874 float expected,
1875 float x) {
1876 return compareAndSetInt(o, offset,
1877 Float.floatToRawIntBits(expected),
1878 Float.floatToRawIntBits(x));
1879 }
1880
1881 @ForceInline
1882 public final float compareAndExchangeFloat(Object o, long offset,
1883 float expected,
1884 float x) {
1885 int w = compareAndExchangeInt(o, offset,
1886 Float.floatToRawIntBits(expected),
1887 Float.floatToRawIntBits(x));
1888 return Float.intBitsToFloat(w);
1889 }
1890
1891 @ForceInline
1892 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1893 float expected,
1894 float x) {
1895 int w = compareAndExchangeIntAcquire(o, offset,
1896 Float.floatToRawIntBits(expected),
1897 Float.floatToRawIntBits(x));
1898 return Float.intBitsToFloat(w);
1899 }
1900
1901 @ForceInline
1902 public final float compareAndExchangeFloatRelease(Object o, long offset,
1903 float expected,
1904 float x) {
1905 int w = compareAndExchangeIntRelease(o, offset,
1906 Float.floatToRawIntBits(expected),
1907 Float.floatToRawIntBits(x));
1908 return Float.intBitsToFloat(w);
1909 }
1910
1911 @ForceInline
1912 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
1913 float expected,
1914 float x) {
1915 return weakCompareAndSetIntPlain(o, offset,
1916 Float.floatToRawIntBits(expected),
1917 Float.floatToRawIntBits(x));
1918 }
1919
1920 @ForceInline
1921 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
1922 float expected,
1923 float x) {
1924 return weakCompareAndSetIntAcquire(o, offset,
1925 Float.floatToRawIntBits(expected),
1926 Float.floatToRawIntBits(x));
1927 }
1928
1929 @ForceInline
1930 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
1931 float expected,
1932 float x) {
1933 return weakCompareAndSetIntRelease(o, offset,
1934 Float.floatToRawIntBits(expected),
1935 Float.floatToRawIntBits(x));
1936 }
1937
1938 @ForceInline
1939 public final boolean weakCompareAndSetFloat(Object o, long offset,
1940 float expected,
1941 float x) {
1942 return weakCompareAndSetInt(o, offset,
1943 Float.floatToRawIntBits(expected),
1944 Float.floatToRawIntBits(x));
1945 }
1946
1947 /**
1948 * Atomically updates Java variable to {@code x} if it is currently
1949 * holding {@code expected}.
1950 *
1951 * <p>This operation has memory semantics of a {@code volatile} read
1952 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1953 *
1954 * @return {@code true} if successful
1955 */
1956 @ForceInline
1957 public final boolean compareAndSetDouble(Object o, long offset,
1958 double expected,
1959 double x) {
1960 return compareAndSetLong(o, offset,
1961 Double.doubleToRawLongBits(expected),
1962 Double.doubleToRawLongBits(x));
1963 }
1964
1965 @ForceInline
1966 public final double compareAndExchangeDouble(Object o, long offset,
1967 double expected,
1968 double x) {
1969 long w = compareAndExchangeLong(o, offset,
1970 Double.doubleToRawLongBits(expected),
1971 Double.doubleToRawLongBits(x));
1972 return Double.longBitsToDouble(w);
1973 }
1974
1975 @ForceInline
1976 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
1977 double expected,
1978 double x) {
1979 long w = compareAndExchangeLongAcquire(o, offset,
1980 Double.doubleToRawLongBits(expected),
1981 Double.doubleToRawLongBits(x));
1982 return Double.longBitsToDouble(w);
1983 }
1984
1985 @ForceInline
1986 public final double compareAndExchangeDoubleRelease(Object o, long offset,
1987 double expected,
1988 double x) {
1989 long w = compareAndExchangeLongRelease(o, offset,
1990 Double.doubleToRawLongBits(expected),
1991 Double.doubleToRawLongBits(x));
1992 return Double.longBitsToDouble(w);
1993 }
1994
1995 @ForceInline
1996 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
1997 double expected,
1998 double x) {
1999 return weakCompareAndSetLongPlain(o, offset,
2000 Double.doubleToRawLongBits(expected),
2001 Double.doubleToRawLongBits(x));
2002 }
2003
2004 @ForceInline
2005 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2006 double expected,
2007 double x) {
2008 return weakCompareAndSetLongAcquire(o, offset,
2009 Double.doubleToRawLongBits(expected),
2010 Double.doubleToRawLongBits(x));
2011 }
2012
2013 @ForceInline
2014 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2015 double expected,
2016 double x) {
2017 return weakCompareAndSetLongRelease(o, offset,
2018 Double.doubleToRawLongBits(expected),
2019 Double.doubleToRawLongBits(x));
2020 }
2021
2022 @ForceInline
2023 public final boolean weakCompareAndSetDouble(Object o, long offset,
2024 double expected,
2025 double x) {
2026 return weakCompareAndSetLong(o, offset,
2027 Double.doubleToRawLongBits(expected),
2028 Double.doubleToRawLongBits(x));
2029 }
2030
2031 /**
2032 * Atomically updates Java variable to {@code x} if it is currently
2033 * holding {@code expected}.
2034 *
2035 * <p>This operation has memory semantics of a {@code volatile} read
2036 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2037 *
2038 * @return {@code true} if successful
2039 */
2040 @HotSpotIntrinsicCandidate
2041 public final native boolean compareAndSetLong(Object o, long offset,
2042 long expected,
2043 long x);
2044
2045 @HotSpotIntrinsicCandidate
2046 public final native long compareAndExchangeLong(Object o, long offset,
2047 long expected,
2048 long x);
2049
2050 @HotSpotIntrinsicCandidate
2051 public final long compareAndExchangeLongAcquire(Object o, long offset,
2052 long expected,
2053 long x) {
2054 return compareAndExchangeLong(o, offset, expected, x);
2055 }
2056
2057 @HotSpotIntrinsicCandidate
2058 public final long compareAndExchangeLongRelease(Object o, long offset,
2059 long expected,
2060 long x) {
2061 return compareAndExchangeLong(o, offset, expected, x);
2062 }
2063
2064 @HotSpotIntrinsicCandidate
2065 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2066 long expected,
2067 long x) {
2068 return compareAndSetLong(o, offset, expected, x);
2069 }
2070
2071 @HotSpotIntrinsicCandidate
2072 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2073 long expected,
2074 long x) {
2075 return compareAndSetLong(o, offset, expected, x);
2076 }
2077
2078 @HotSpotIntrinsicCandidate
2079 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2080 long expected,
2081 long x) {
2082 return compareAndSetLong(o, offset, expected, x);
2083 }
2084
2085 @HotSpotIntrinsicCandidate
2086 public final boolean weakCompareAndSetLong(Object o, long offset,
2087 long expected,
2088 long x) {
2089 return compareAndSetLong(o, offset, expected, x);
2090 }
2091
2092 /**
2093 * Fetches a reference value from a given Java variable, with volatile
2094 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2095 */
2096 @HotSpotIntrinsicCandidate
2097 public native Object getReferenceVolatile(Object o, long offset);
2098
2099 /**
2100 * Stores a reference value into a given Java variable, with
2101 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2102 */
2103 @HotSpotIntrinsicCandidate
2104 public native void putReferenceVolatile(Object o, long offset, Object x);
2105
2106 /** Volatile version of {@link #getInt(Object, long)} */
2107 @HotSpotIntrinsicCandidate
2108 public native int getIntVolatile(Object o, long offset);
2109
2110 /** Volatile version of {@link #putInt(Object, long, int)} */
2111 @HotSpotIntrinsicCandidate
2112 public native void putIntVolatile(Object o, long offset, int x);
2113
2114 /** Volatile version of {@link #getBoolean(Object, long)} */
2115 @HotSpotIntrinsicCandidate
2116 public native boolean getBooleanVolatile(Object o, long offset);
2117
2118 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2119 @HotSpotIntrinsicCandidate
2120 public native void putBooleanVolatile(Object o, long offset, boolean x);
2121
2122 /** Volatile version of {@link #getByte(Object, long)} */
2123 @HotSpotIntrinsicCandidate
2124 public native byte getByteVolatile(Object o, long offset);
2125
2126 /** Volatile version of {@link #putByte(Object, long, byte)} */
2127 @HotSpotIntrinsicCandidate
2128 public native void putByteVolatile(Object o, long offset, byte x);
2129
2130 /** Volatile version of {@link #getShort(Object, long)} */
2131 @HotSpotIntrinsicCandidate
2132 public native short getShortVolatile(Object o, long offset);
2133
2134 /** Volatile version of {@link #putShort(Object, long, short)} */
2135 @HotSpotIntrinsicCandidate
2136 public native void putShortVolatile(Object o, long offset, short x);
2137
2138 /** Volatile version of {@link #getChar(Object, long)} */
2139 @HotSpotIntrinsicCandidate
2140 public native char getCharVolatile(Object o, long offset);
2141
2142 /** Volatile version of {@link #putChar(Object, long, char)} */
2143 @HotSpotIntrinsicCandidate
2144 public native void putCharVolatile(Object o, long offset, char x);
2145
2146 /** Volatile version of {@link #getLong(Object, long)} */
2147 @HotSpotIntrinsicCandidate
2148 public native long getLongVolatile(Object o, long offset);
2149
2150 /** Volatile version of {@link #putLong(Object, long, long)} */
2151 @HotSpotIntrinsicCandidate
2152 public native void putLongVolatile(Object o, long offset, long x);
2153
2154 /** Volatile version of {@link #getFloat(Object, long)} */
2155 @HotSpotIntrinsicCandidate
2156 public native float getFloatVolatile(Object o, long offset);
2157
2158 /** Volatile version of {@link #putFloat(Object, long, float)} */
2159 @HotSpotIntrinsicCandidate
2160 public native void putFloatVolatile(Object o, long offset, float x);
2161
2162 /** Volatile version of {@link #getDouble(Object, long)} */
2163 @HotSpotIntrinsicCandidate
2164 public native double getDoubleVolatile(Object o, long offset);
2165
2166 /** Volatile version of {@link #putDouble(Object, long, double)} */
2167 @HotSpotIntrinsicCandidate
2168 public native void putDoubleVolatile(Object o, long offset, double x);
2169
2170
2171
2172 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2173 @HotSpotIntrinsicCandidate
2174 public final Object getReferenceAcquire(Object o, long offset) {
2175 return getReferenceVolatile(o, offset);
2176 }
2177
2178 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2179 @HotSpotIntrinsicCandidate
2180 public final boolean getBooleanAcquire(Object o, long offset) {
2181 return getBooleanVolatile(o, offset);
2182 }
2183
2184 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2185 @HotSpotIntrinsicCandidate
2186 public final byte getByteAcquire(Object o, long offset) {
2187 return getByteVolatile(o, offset);
2188 }
2189
2190 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2191 @HotSpotIntrinsicCandidate
2192 public final short getShortAcquire(Object o, long offset) {
2193 return getShortVolatile(o, offset);
2194 }
2195
2196 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2197 @HotSpotIntrinsicCandidate
2198 public final char getCharAcquire(Object o, long offset) {
2199 return getCharVolatile(o, offset);
2200 }
2201
2202 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2203 @HotSpotIntrinsicCandidate
2204 public final int getIntAcquire(Object o, long offset) {
2205 return getIntVolatile(o, offset);
2206 }
2207
2208 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2209 @HotSpotIntrinsicCandidate
2210 public final float getFloatAcquire(Object o, long offset) {
2211 return getFloatVolatile(o, offset);
2212 }
2213
2214 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2215 @HotSpotIntrinsicCandidate
2216 public final long getLongAcquire(Object o, long offset) {
2217 return getLongVolatile(o, offset);
2218 }
2219
2220 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2221 @HotSpotIntrinsicCandidate
2222 public final double getDoubleAcquire(Object o, long offset) {
2223 return getDoubleVolatile(o, offset);
2224 }
2225
2226 /*
2227 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2228 * that do not guarantee immediate visibility of the store to
2229 * other threads. This method is generally only useful if the
2230 * underlying field is a Java volatile (or if an array cell, one
2231 * that is otherwise only accessed using volatile accesses).
2232 *
2233 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2234 */
2235
2236 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2237 @HotSpotIntrinsicCandidate
2238 public final void putReferenceRelease(Object o, long offset, Object x) {
2239 putReferenceVolatile(o, offset, x);
2240 }
2241
2242 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2243 @HotSpotIntrinsicCandidate
2244 public final void putBooleanRelease(Object o, long offset, boolean x) {
2245 putBooleanVolatile(o, offset, x);
2246 }
2247
2248 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2249 @HotSpotIntrinsicCandidate
2250 public final void putByteRelease(Object o, long offset, byte x) {
2251 putByteVolatile(o, offset, x);
2252 }
2253
2254 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2255 @HotSpotIntrinsicCandidate
2256 public final void putShortRelease(Object o, long offset, short x) {
2257 putShortVolatile(o, offset, x);
2258 }
2259
2260 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2261 @HotSpotIntrinsicCandidate
2262 public final void putCharRelease(Object o, long offset, char x) {
2263 putCharVolatile(o, offset, x);
2264 }
2265
2266 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2267 @HotSpotIntrinsicCandidate
2268 public final void putIntRelease(Object o, long offset, int x) {
2269 putIntVolatile(o, offset, x);
2270 }
2271
2272 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2273 @HotSpotIntrinsicCandidate
2274 public final void putFloatRelease(Object o, long offset, float x) {
2275 putFloatVolatile(o, offset, x);
2276 }
2277
2278 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2279 @HotSpotIntrinsicCandidate
2280 public final void putLongRelease(Object o, long offset, long x) {
2281 putLongVolatile(o, offset, x);
2282 }
2283
2284 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2285 @HotSpotIntrinsicCandidate
2286 public final void putDoubleRelease(Object o, long offset, double x) {
2287 putDoubleVolatile(o, offset, x);
2288 }
2289
2290 // ------------------------------ Opaque --------------------------------------
2291
2292 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2293 @HotSpotIntrinsicCandidate
2294 public final Object getReferenceOpaque(Object o, long offset) {
2295 return getReferenceVolatile(o, offset);
2296 }
2297
2298 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2299 @HotSpotIntrinsicCandidate
2300 public final boolean getBooleanOpaque(Object o, long offset) {
2301 return getBooleanVolatile(o, offset);
2302 }
2303
2304 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2305 @HotSpotIntrinsicCandidate
2306 public final byte getByteOpaque(Object o, long offset) {
2307 return getByteVolatile(o, offset);
2308 }
2309
2310 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2311 @HotSpotIntrinsicCandidate
2312 public final short getShortOpaque(Object o, long offset) {
2313 return getShortVolatile(o, offset);
2314 }
2315
2316 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2317 @HotSpotIntrinsicCandidate
2318 public final char getCharOpaque(Object o, long offset) {
2319 return getCharVolatile(o, offset);
2320 }
2321
2322 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2323 @HotSpotIntrinsicCandidate
2324 public final int getIntOpaque(Object o, long offset) {
2325 return getIntVolatile(o, offset);
2326 }
2327
2328 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2329 @HotSpotIntrinsicCandidate
2330 public final float getFloatOpaque(Object o, long offset) {
2331 return getFloatVolatile(o, offset);
2332 }
2333
2334 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2335 @HotSpotIntrinsicCandidate
2336 public final long getLongOpaque(Object o, long offset) {
2337 return getLongVolatile(o, offset);
2338 }
2339
2340 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2341 @HotSpotIntrinsicCandidate
2342 public final double getDoubleOpaque(Object o, long offset) {
2343 return getDoubleVolatile(o, offset);
2344 }
2345
2346 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2347 @HotSpotIntrinsicCandidate
2348 public final void putReferenceOpaque(Object o, long offset, Object x) {
2349 putReferenceVolatile(o, offset, x);
2350 }
2351
2352 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2353 @HotSpotIntrinsicCandidate
2354 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2355 putBooleanVolatile(o, offset, x);
2356 }
2357
2358 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2359 @HotSpotIntrinsicCandidate
2360 public final void putByteOpaque(Object o, long offset, byte x) {
2361 putByteVolatile(o, offset, x);
2362 }
2363
2364 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2365 @HotSpotIntrinsicCandidate
2366 public final void putShortOpaque(Object o, long offset, short x) {
2367 putShortVolatile(o, offset, x);
2368 }
2369
2370 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2371 @HotSpotIntrinsicCandidate
2372 public final void putCharOpaque(Object o, long offset, char x) {
2373 putCharVolatile(o, offset, x);
2374 }
2375
2376 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2377 @HotSpotIntrinsicCandidate
2378 public final void putIntOpaque(Object o, long offset, int x) {
2379 putIntVolatile(o, offset, x);
2380 }
2381
2382 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2383 @HotSpotIntrinsicCandidate
2384 public final void putFloatOpaque(Object o, long offset, float x) {
2385 putFloatVolatile(o, offset, x);
2386 }
2387
2388 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2389 @HotSpotIntrinsicCandidate
2390 public final void putLongOpaque(Object o, long offset, long x) {
2391 putLongVolatile(o, offset, x);
2392 }
2393
2394 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2395 @HotSpotIntrinsicCandidate
2396 public final void putDoubleOpaque(Object o, long offset, double x) {
2397 putDoubleVolatile(o, offset, x);
2398 }
2399
2400 /**
2401 * Unblocks the given thread blocked on {@code park}, or, if it is
2402 * not blocked, causes the subsequent call to {@code park} not to
2403 * block. Note: this operation is "unsafe" solely because the
2404 * caller must somehow ensure that the thread has not been
2405 * destroyed. Nothing special is usually required to ensure this
2406 * when called from Java (in which there will ordinarily be a live
2407 * reference to the thread) but this is not nearly-automatically
2408 * so when calling from native code.
2409 *
2410 * @param thread the thread to unpark.
2411 */
2412 @HotSpotIntrinsicCandidate
2413 public native void unpark(Object thread);
2414
2415 /**
2416 * Blocks current thread, returning when a balancing
2417 * {@code unpark} occurs, or a balancing {@code unpark} has
2418 * already occurred, or the thread is interrupted, or, if not
2419 * absolute and time is not zero, the given time nanoseconds have
2420 * elapsed, or if absolute, the given deadline in milliseconds
2421 * since Epoch has passed, or spuriously (i.e., returning for no
2422 * "reason"). Note: This operation is in the Unsafe class only
2423 * because {@code unpark} is, so it would be strange to place it
2424 * elsewhere.
2425 */
2426 @HotSpotIntrinsicCandidate
2427 public native void park(boolean isAbsolute, long time);
2428
2429 /**
2430 * Gets the load average in the system run queue assigned
2431 * to the available processors averaged over various periods of time.
2432 * This method retrieves the given {@code nelem} samples and
2433 * assigns to the elements of the given {@code loadavg} array.
2434 * The system imposes a maximum of 3 samples, representing
2435 * averages over the last 1, 5, and 15 minutes, respectively.
2436 *
2437 * @param loadavg an array of double of size nelems
2438 * @param nelems the number of samples to be retrieved and
2439 * must be 1 to 3.
2440 *
2441 * @return the number of samples actually retrieved; or -1
2442 * if the load average is unobtainable.
2443 */
2444 public int getLoadAverage(double[] loadavg, int nelems) {
2445 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2446 throw new ArrayIndexOutOfBoundsException();
2447 }
2448
2449 return getLoadAverage0(loadavg, nelems);
2450 }
2451
2452 // The following contain CAS-based Java implementations used on
2453 // platforms not supporting native instructions
2454
2455 /**
2456 * Atomically adds the given value to the current value of a field
2457 * or array element within the given object {@code o}
2458 * at the given {@code offset}.
2459 *
2460 * @param o object/array to update the field/element in
2461 * @param offset field/element offset
2462 * @param delta the value to add
2463 * @return the previous value
2464 * @since 1.8
2465 */
2466 @HotSpotIntrinsicCandidate
2467 public final int getAndAddInt(Object o, long offset, int delta) {
2468 int v;
2469 do {
2470 v = getIntVolatile(o, offset);
2471 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2472 return v;
2473 }
2474
2475 @ForceInline
2476 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2477 int v;
2478 do {
2479 v = getInt(o, offset);
2480 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2481 return v;
2482 }
2483
2484 @ForceInline
2485 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2486 int v;
2487 do {
2488 v = getIntAcquire(o, offset);
2489 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2490 return v;
2491 }
2492
2493 /**
2494 * Atomically adds the given value to the current value of a field
2495 * or array element within the given object {@code o}
2496 * at the given {@code offset}.
2497 *
2498 * @param o object/array to update the field/element in
2499 * @param offset field/element offset
2500 * @param delta the value to add
2501 * @return the previous value
2502 * @since 1.8
2503 */
2504 @HotSpotIntrinsicCandidate
2505 public final long getAndAddLong(Object o, long offset, long delta) {
2506 long v;
2507 do {
2508 v = getLongVolatile(o, offset);
2509 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2510 return v;
2511 }
2512
2513 @ForceInline
2514 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2515 long v;
2516 do {
2517 v = getLong(o, offset);
2518 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2519 return v;
2520 }
2521
2522 @ForceInline
2523 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2524 long v;
2525 do {
2526 v = getLongAcquire(o, offset);
2527 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2528 return v;
2529 }
2530
2531 @HotSpotIntrinsicCandidate
2532 public final byte getAndAddByte(Object o, long offset, byte delta) {
2533 byte v;
2534 do {
2535 v = getByteVolatile(o, offset);
2536 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2537 return v;
2538 }
2539
2540 @ForceInline
2541 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2542 byte v;
2543 do {
2544 v = getByte(o, offset);
2545 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2546 return v;
2547 }
2548
2549 @ForceInline
2550 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2551 byte v;
2552 do {
2553 v = getByteAcquire(o, offset);
2554 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2555 return v;
2556 }
2557
2558 @HotSpotIntrinsicCandidate
2559 public final short getAndAddShort(Object o, long offset, short delta) {
2560 short v;
2561 do {
2562 v = getShortVolatile(o, offset);
2563 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2564 return v;
2565 }
2566
2567 @ForceInline
2568 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2569 short v;
2570 do {
2571 v = getShort(o, offset);
2572 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2573 return v;
2574 }
2575
2576 @ForceInline
2577 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2578 short v;
2579 do {
2580 v = getShortAcquire(o, offset);
2581 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2582 return v;
2583 }
2584
2585 @ForceInline
2586 public final char getAndAddChar(Object o, long offset, char delta) {
2587 return (char) getAndAddShort(o, offset, (short) delta);
2588 }
2589
2590 @ForceInline
2591 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2592 return (char) getAndAddShortRelease(o, offset, (short) delta);
2593 }
2594
2595 @ForceInline
2596 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2597 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2598 }
2599
2600 @ForceInline
2601 public final float getAndAddFloat(Object o, long offset, float delta) {
2602 int expectedBits;
2603 float v;
2604 do {
2605 // Load and CAS with the raw bits to avoid issues with NaNs and
2606 // possible bit conversion from signaling NaNs to quiet NaNs that
2607 // may result in the loop not terminating.
2608 expectedBits = getIntVolatile(o, offset);
2609 v = Float.intBitsToFloat(expectedBits);
2610 } while (!weakCompareAndSetInt(o, offset,
2611 expectedBits, Float.floatToRawIntBits(v + delta)));
2612 return v;
2613 }
2614
2615 @ForceInline
2616 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2617 int expectedBits;
2618 float v;
2619 do {
2620 // Load and CAS with the raw bits to avoid issues with NaNs and
2621 // possible bit conversion from signaling NaNs to quiet NaNs that
2622 // may result in the loop not terminating.
2623 expectedBits = getInt(o, offset);
2624 v = Float.intBitsToFloat(expectedBits);
2625 } while (!weakCompareAndSetIntRelease(o, offset,
2626 expectedBits, Float.floatToRawIntBits(v + delta)));
2627 return v;
2628 }
2629
2630 @ForceInline
2631 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2632 int expectedBits;
2633 float v;
2634 do {
2635 // Load and CAS with the raw bits to avoid issues with NaNs and
2636 // possible bit conversion from signaling NaNs to quiet NaNs that
2637 // may result in the loop not terminating.
2638 expectedBits = getIntAcquire(o, offset);
2639 v = Float.intBitsToFloat(expectedBits);
2640 } while (!weakCompareAndSetIntAcquire(o, offset,
2641 expectedBits, Float.floatToRawIntBits(v + delta)));
2642 return v;
2643 }
2644
2645 @ForceInline
2646 public final double getAndAddDouble(Object o, long offset, double delta) {
2647 long expectedBits;
2648 double v;
2649 do {
2650 // Load and CAS with the raw bits to avoid issues with NaNs and
2651 // possible bit conversion from signaling NaNs to quiet NaNs that
2652 // may result in the loop not terminating.
2653 expectedBits = getLongVolatile(o, offset);
2654 v = Double.longBitsToDouble(expectedBits);
2655 } while (!weakCompareAndSetLong(o, offset,
2656 expectedBits, Double.doubleToRawLongBits(v + delta)));
2657 return v;
2658 }
2659
2660 @ForceInline
2661 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2662 long expectedBits;
2663 double v;
2664 do {
2665 // Load and CAS with the raw bits to avoid issues with NaNs and
2666 // possible bit conversion from signaling NaNs to quiet NaNs that
2667 // may result in the loop not terminating.
2668 expectedBits = getLong(o, offset);
2669 v = Double.longBitsToDouble(expectedBits);
2670 } while (!weakCompareAndSetLongRelease(o, offset,
2671 expectedBits, Double.doubleToRawLongBits(v + delta)));
2672 return v;
2673 }
2674
2675 @ForceInline
2676 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2677 long expectedBits;
2678 double v;
2679 do {
2680 // Load and CAS with the raw bits to avoid issues with NaNs and
2681 // possible bit conversion from signaling NaNs to quiet NaNs that
2682 // may result in the loop not terminating.
2683 expectedBits = getLongAcquire(o, offset);
2684 v = Double.longBitsToDouble(expectedBits);
2685 } while (!weakCompareAndSetLongAcquire(o, offset,
2686 expectedBits, Double.doubleToRawLongBits(v + delta)));
2687 return v;
2688 }
2689
2690 /**
2691 * Atomically exchanges the given value with the current value of
2692 * a field or array element within the given object {@code o}
2693 * at the given {@code offset}.
2694 *
2695 * @param o object/array to update the field/element in
2696 * @param offset field/element offset
2697 * @param newValue new value
2698 * @return the previous value
2699 * @since 1.8
2700 */
2701 @HotSpotIntrinsicCandidate
2702 public final int getAndSetInt(Object o, long offset, int newValue) {
2703 int v;
2704 do {
2705 v = getIntVolatile(o, offset);
2706 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2707 return v;
2708 }
2709
2710 @ForceInline
2711 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2712 int v;
2713 do {
2714 v = getInt(o, offset);
2715 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2716 return v;
2717 }
2718
2719 @ForceInline
2720 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2721 int v;
2722 do {
2723 v = getIntAcquire(o, offset);
2724 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2725 return v;
2726 }
2727
2728 /**
2729 * Atomically exchanges the given value with the current value of
2730 * a field or array element within the given object {@code o}
2731 * at the given {@code offset}.
2732 *
2733 * @param o object/array to update the field/element in
2734 * @param offset field/element offset
2735 * @param newValue new value
2736 * @return the previous value
2737 * @since 1.8
2738 */
2739 @HotSpotIntrinsicCandidate
2740 public final long getAndSetLong(Object o, long offset, long newValue) {
2741 long v;
2742 do {
2743 v = getLongVolatile(o, offset);
2744 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2745 return v;
2746 }
2747
2748 @ForceInline
2749 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2750 long v;
2751 do {
2752 v = getLong(o, offset);
2753 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2754 return v;
2755 }
2756
2757 @ForceInline
2758 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2759 long v;
2760 do {
2761 v = getLongAcquire(o, offset);
2762 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2763 return v;
2764 }
2765
2766 /**
2767 * Atomically exchanges the given reference value with the current
2768 * reference value of a field or array element within the given
2769 * object {@code o} at the given {@code offset}.
2770 *
2771 * @param o object/array to update the field/element in
2772 * @param offset field/element offset
2773 * @param newValue new value
2774 * @return the previous value
2775 * @since 1.8
2776 */
2777 @HotSpotIntrinsicCandidate
2778 public final Object getAndSetReference(Object o, long offset, Object newValue) {
2779 Object v;
2780 do {
2781 v = getReferenceVolatile(o, offset);
2782 } while (!weakCompareAndSetReference(o, offset, v, newValue));
2783 return v;
2784 }
2785
2786 @ForceInline
2787 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
2788 Object v;
2789 do {
2790 v = getReference(o, offset);
2791 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
2792 return v;
2793 }
2794
2795 @ForceInline
2796 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
2797 Object v;
2798 do {
2799 v = getReferenceAcquire(o, offset);
2800 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
2801 return v;
2802 }
2803
2804 @HotSpotIntrinsicCandidate
2805 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2806 byte v;
2807 do {
2808 v = getByteVolatile(o, offset);
2809 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2810 return v;
2811 }
2812
2813 @ForceInline
2814 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2815 byte v;
2816 do {
2817 v = getByte(o, offset);
2818 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2819 return v;
2820 }
2821
2822 @ForceInline
2823 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2824 byte v;
2825 do {
2826 v = getByteAcquire(o, offset);
2827 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2828 return v;
2829 }
2830
2831 @ForceInline
2832 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2833 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2834 }
2835
2836 @ForceInline
2837 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2838 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2839 }
2840
2841 @ForceInline
2842 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2843 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2844 }
2845
2846 @HotSpotIntrinsicCandidate
2847 public final short getAndSetShort(Object o, long offset, short newValue) {
2848 short v;
2849 do {
2850 v = getShortVolatile(o, offset);
2851 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2852 return v;
2853 }
2854
2855 @ForceInline
2856 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
2857 short v;
2858 do {
2859 v = getShort(o, offset);
2860 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
2861 return v;
2862 }
2863
2864 @ForceInline
2865 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
2866 short v;
2867 do {
2868 v = getShortAcquire(o, offset);
2869 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
2870 return v;
2871 }
2872
2873 @ForceInline
2874 public final char getAndSetChar(Object o, long offset, char newValue) {
2875 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2876 }
2877
2878 @ForceInline
2879 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
2880 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
2881 }
2882
2883 @ForceInline
2884 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
2885 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
2886 }
2887
2888 @ForceInline
2889 public final float getAndSetFloat(Object o, long offset, float newValue) {
2890 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
2891 return Float.intBitsToFloat(v);
2892 }
2893
2894 @ForceInline
2895 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
2896 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
2897 return Float.intBitsToFloat(v);
2898 }
2899
2900 @ForceInline
2901 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
2902 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
2903 return Float.intBitsToFloat(v);
2904 }
2905
2906 @ForceInline
2907 public final double getAndSetDouble(Object o, long offset, double newValue) {
2908 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
2909 return Double.longBitsToDouble(v);
2910 }
2911
2912 @ForceInline
2913 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
2914 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
2915 return Double.longBitsToDouble(v);
2916 }
2917
2918 @ForceInline
2919 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
2920 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
2921 return Double.longBitsToDouble(v);
2922 }
2923
2924
2925 // The following contain CAS-based Java implementations used on
2926 // platforms not supporting native instructions
2927
2928 @ForceInline
2929 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
2930 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
2931 }
2932
2933 @ForceInline
2934 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
2935 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
2936 }
2937
2938 @ForceInline
2939 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
2940 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
2941 }
2942
2943 @ForceInline
2944 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
2945 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
2946 }
2947
2948 @ForceInline
2949 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
2950 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
2951 }
2952
2953 @ForceInline
2954 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
2955 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
2956 }
2957
2958 @ForceInline
2959 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
2960 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
2961 }
2962
2963 @ForceInline
2964 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
2965 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
2966 }
2967
2968 @ForceInline
2969 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
2970 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
2971 }
2972
2973
2974 @ForceInline
2975 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
2976 byte current;
2977 do {
2978 current = getByteVolatile(o, offset);
2979 } while (!weakCompareAndSetByte(o, offset,
2980 current, (byte) (current | mask)));
2981 return current;
2982 }
2983
2984 @ForceInline
2985 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
2986 byte current;
2987 do {
2988 current = getByte(o, offset);
2989 } while (!weakCompareAndSetByteRelease(o, offset,
2990 current, (byte) (current | mask)));
2991 return current;
2992 }
2993
2994 @ForceInline
2995 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
2996 byte current;
2997 do {
2998 // Plain read, the value is a hint, the acquire CAS does the work
2999 current = getByte(o, offset);
3000 } while (!weakCompareAndSetByteAcquire(o, offset,
3001 current, (byte) (current | mask)));
3002 return current;
3003 }
3004
3005 @ForceInline
3006 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3007 byte current;
3008 do {
3009 current = getByteVolatile(o, offset);
3010 } while (!weakCompareAndSetByte(o, offset,
3011 current, (byte) (current & mask)));
3012 return current;
3013 }
3014
3015 @ForceInline
3016 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3017 byte current;
3018 do {
3019 current = getByte(o, offset);
3020 } while (!weakCompareAndSetByteRelease(o, offset,
3021 current, (byte) (current & mask)));
3022 return current;
3023 }
3024
3025 @ForceInline
3026 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3027 byte current;
3028 do {
3029 // Plain read, the value is a hint, the acquire CAS does the work
3030 current = getByte(o, offset);
3031 } while (!weakCompareAndSetByteAcquire(o, offset,
3032 current, (byte) (current & mask)));
3033 return current;
3034 }
3035
3036 @ForceInline
3037 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3038 byte current;
3039 do {
3040 current = getByteVolatile(o, offset);
3041 } while (!weakCompareAndSetByte(o, offset,
3042 current, (byte) (current ^ mask)));
3043 return current;
3044 }
3045
3046 @ForceInline
3047 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3048 byte current;
3049 do {
3050 current = getByte(o, offset);
3051 } while (!weakCompareAndSetByteRelease(o, offset,
3052 current, (byte) (current ^ mask)));
3053 return current;
3054 }
3055
3056 @ForceInline
3057 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3058 byte current;
3059 do {
3060 // Plain read, the value is a hint, the acquire CAS does the work
3061 current = getByte(o, offset);
3062 } while (!weakCompareAndSetByteAcquire(o, offset,
3063 current, (byte) (current ^ mask)));
3064 return current;
3065 }
3066
3067
3068 @ForceInline
3069 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3070 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3071 }
3072
3073 @ForceInline
3074 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3075 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3076 }
3077
3078 @ForceInline
3079 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3080 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3081 }
3082
3083 @ForceInline
3084 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3085 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3086 }
3087
3088 @ForceInline
3089 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3090 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3091 }
3092
3093 @ForceInline
3094 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3095 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3096 }
3097
3098 @ForceInline
3099 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3100 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3101 }
3102
3103 @ForceInline
3104 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3105 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3106 }
3107
3108 @ForceInline
3109 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3110 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3111 }
3112
3113
3114 @ForceInline
3115 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3116 short current;
3117 do {
3118 current = getShortVolatile(o, offset);
3119 } while (!weakCompareAndSetShort(o, offset,
3120 current, (short) (current | mask)));
3121 return current;
3122 }
3123
3124 @ForceInline
3125 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3126 short current;
3127 do {
3128 current = getShort(o, offset);
3129 } while (!weakCompareAndSetShortRelease(o, offset,
3130 current, (short) (current | mask)));
3131 return current;
3132 }
3133
3134 @ForceInline
3135 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3136 short current;
3137 do {
3138 // Plain read, the value is a hint, the acquire CAS does the work
3139 current = getShort(o, offset);
3140 } while (!weakCompareAndSetShortAcquire(o, offset,
3141 current, (short) (current | mask)));
3142 return current;
3143 }
3144
3145 @ForceInline
3146 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3147 short current;
3148 do {
3149 current = getShortVolatile(o, offset);
3150 } while (!weakCompareAndSetShort(o, offset,
3151 current, (short) (current & mask)));
3152 return current;
3153 }
3154
3155 @ForceInline
3156 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3157 short current;
3158 do {
3159 current = getShort(o, offset);
3160 } while (!weakCompareAndSetShortRelease(o, offset,
3161 current, (short) (current & mask)));
3162 return current;
3163 }
3164
3165 @ForceInline
3166 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3167 short current;
3168 do {
3169 // Plain read, the value is a hint, the acquire CAS does the work
3170 current = getShort(o, offset);
3171 } while (!weakCompareAndSetShortAcquire(o, offset,
3172 current, (short) (current & mask)));
3173 return current;
3174 }
3175
3176 @ForceInline
3177 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3178 short current;
3179 do {
3180 current = getShortVolatile(o, offset);
3181 } while (!weakCompareAndSetShort(o, offset,
3182 current, (short) (current ^ mask)));
3183 return current;
3184 }
3185
3186 @ForceInline
3187 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3188 short current;
3189 do {
3190 current = getShort(o, offset);
3191 } while (!weakCompareAndSetShortRelease(o, offset,
3192 current, (short) (current ^ mask)));
3193 return current;
3194 }
3195
3196 @ForceInline
3197 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3198 short current;
3199 do {
3200 // Plain read, the value is a hint, the acquire CAS does the work
3201 current = getShort(o, offset);
3202 } while (!weakCompareAndSetShortAcquire(o, offset,
3203 current, (short) (current ^ mask)));
3204 return current;
3205 }
3206
3207
3208 @ForceInline
3209 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3210 int current;
3211 do {
3212 current = getIntVolatile(o, offset);
3213 } while (!weakCompareAndSetInt(o, offset,
3214 current, current | mask));
3215 return current;
3216 }
3217
3218 @ForceInline
3219 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3220 int current;
3221 do {
3222 current = getInt(o, offset);
3223 } while (!weakCompareAndSetIntRelease(o, offset,
3224 current, current | mask));
3225 return current;
3226 }
3227
3228 @ForceInline
3229 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3230 int current;
3231 do {
3232 // Plain read, the value is a hint, the acquire CAS does the work
3233 current = getInt(o, offset);
3234 } while (!weakCompareAndSetIntAcquire(o, offset,
3235 current, current | mask));
3236 return current;
3237 }
3238
3239 /**
3240 * Atomically replaces the current value of a field or array element within
3241 * the given object with the result of bitwise AND between the current value
3242 * and mask.
3243 *
3244 * @param o object/array to update the field/element in
3245 * @param offset field/element offset
3246 * @param mask the mask value
3247 * @return the previous value
3248 * @since 9
3249 */
3250 @ForceInline
3251 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3252 int current;
3253 do {
3254 current = getIntVolatile(o, offset);
3255 } while (!weakCompareAndSetInt(o, offset,
3256 current, current & mask));
3257 return current;
3258 }
3259
3260 @ForceInline
3261 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3262 int current;
3263 do {
3264 current = getInt(o, offset);
3265 } while (!weakCompareAndSetIntRelease(o, offset,
3266 current, current & mask));
3267 return current;
3268 }
3269
3270 @ForceInline
3271 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3272 int current;
3273 do {
3274 // Plain read, the value is a hint, the acquire CAS does the work
3275 current = getInt(o, offset);
3276 } while (!weakCompareAndSetIntAcquire(o, offset,
3277 current, current & mask));
3278 return current;
3279 }
3280
3281 @ForceInline
3282 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3283 int current;
3284 do {
3285 current = getIntVolatile(o, offset);
3286 } while (!weakCompareAndSetInt(o, offset,
3287 current, current ^ mask));
3288 return current;
3289 }
3290
3291 @ForceInline
3292 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3293 int current;
3294 do {
3295 current = getInt(o, offset);
3296 } while (!weakCompareAndSetIntRelease(o, offset,
3297 current, current ^ mask));
3298 return current;
3299 }
3300
3301 @ForceInline
3302 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3303 int current;
3304 do {
3305 // Plain read, the value is a hint, the acquire CAS does the work
3306 current = getInt(o, offset);
3307 } while (!weakCompareAndSetIntAcquire(o, offset,
3308 current, current ^ mask));
3309 return current;
3310 }
3311
3312
3313 @ForceInline
3314 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3315 long current;
3316 do {
3317 current = getLongVolatile(o, offset);
3318 } while (!weakCompareAndSetLong(o, offset,
3319 current, current | mask));
3320 return current;
3321 }
3322
3323 @ForceInline
3324 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3325 long current;
3326 do {
3327 current = getLong(o, offset);
3328 } while (!weakCompareAndSetLongRelease(o, offset,
3329 current, current | mask));
3330 return current;
3331 }
3332
3333 @ForceInline
3334 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3335 long current;
3336 do {
3337 // Plain read, the value is a hint, the acquire CAS does the work
3338 current = getLong(o, offset);
3339 } while (!weakCompareAndSetLongAcquire(o, offset,
3340 current, current | mask));
3341 return current;
3342 }
3343
3344 @ForceInline
3345 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3346 long current;
3347 do {
3348 current = getLongVolatile(o, offset);
3349 } while (!weakCompareAndSetLong(o, offset,
3350 current, current & mask));
3351 return current;
3352 }
3353
3354 @ForceInline
3355 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3356 long current;
3357 do {
3358 current = getLong(o, offset);
3359 } while (!weakCompareAndSetLongRelease(o, offset,
3360 current, current & mask));
3361 return current;
3362 }
3363
3364 @ForceInline
3365 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3366 long current;
3367 do {
3368 // Plain read, the value is a hint, the acquire CAS does the work
3369 current = getLong(o, offset);
3370 } while (!weakCompareAndSetLongAcquire(o, offset,
3371 current, current & mask));
3372 return current;
3373 }
3374
3375 @ForceInline
3376 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3377 long current;
3378 do {
3379 current = getLongVolatile(o, offset);
3380 } while (!weakCompareAndSetLong(o, offset,
3381 current, current ^ mask));
3382 return current;
3383 }
3384
3385 @ForceInline
3386 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3387 long current;
3388 do {
3389 current = getLong(o, offset);
3390 } while (!weakCompareAndSetLongRelease(o, offset,
3391 current, current ^ mask));
3392 return current;
3393 }
3394
3395 @ForceInline
3396 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3397 long current;
3398 do {
3399 // Plain read, the value is a hint, the acquire CAS does the work
3400 current = getLong(o, offset);
3401 } while (!weakCompareAndSetLongAcquire(o, offset,
3402 current, current ^ mask));
3403 return current;
3404 }
3405
3406
3407
3408 /**
3409 * Ensures that loads before the fence will not be reordered with loads and
3410 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3411 *
3412 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3413 * (an "acquire fence").
3414 *
3415 * A pure LoadLoad fence is not provided, since the addition of LoadStore
3416 * is almost always desired, and most current hardware instructions that
3417 * provide a LoadLoad barrier also provide a LoadStore barrier for free.
3418 * @since 1.8
3419 */
3420 @HotSpotIntrinsicCandidate
3421 public native void loadFence();
3422
3423 /**
3424 * Ensures that loads and stores before the fence will not be reordered with
3425 * stores after the fence; a "StoreStore plus LoadStore barrier".
3426 *
3427 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3428 * (a "release fence").
3429 *
3430 * A pure StoreStore fence is not provided, since the addition of LoadStore
3431 * is almost always desired, and most current hardware instructions that
3432 * provide a StoreStore barrier also provide a LoadStore barrier for free.
3433 * @since 1.8
3434 */
3435 @HotSpotIntrinsicCandidate
3436 public native void storeFence();
3437
3438 /**
3439 * Ensures that loads and stores before the fence will not be reordered
3440 * with loads and stores after the fence. Implies the effects of both
3441 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3442 * barrier.
3443 *
3444 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3445 * @since 1.8
3446 */
3447 @HotSpotIntrinsicCandidate
3448 public native void fullFence();
3449
3450 /**
3451 * Ensures that loads before the fence will not be reordered with
3452 * loads after the fence.
3453 */
3454 public final void loadLoadFence() {
3455 loadFence();
3456 }
3457
3458 /**
3459 * Ensures that stores before the fence will not be reordered with
3460 * stores after the fence.
3461 */
3462 public final void storeStoreFence() {
3463 storeFence();
3464 }
3465
3466
3467 /**
3468 * Throws IllegalAccessError; for use by the VM for access control
3469 * error support.
3470 * @since 1.8
3471 */
3472 private static void throwIllegalAccessError() {
3473 throw new IllegalAccessError();
3474 }
3475
3476 /**
3477 * Throws NoSuchMethodError; for use by the VM for redefinition support.
3478 * @since 13
3479 */
3480 private static void throwNoSuchMethodError() {
3481 throw new NoSuchMethodError();
3482 }
3483
3484 /**
3485 * @return Returns true if the native byte ordering of this
3486 * platform is big-endian, false if it is little-endian.
3487 */
3488 public final boolean isBigEndian() { return BIG_ENDIAN; }
3489
3490 /**
3491 * @return Returns true if this platform is capable of performing
3492 * accesses at addresses which are not aligned for the type of the
3493 * primitive type being accessed, false otherwise.
3494 */
3495 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
3496
3497 /**
3498 * Fetches a value at some byte offset into a given Java object.
3499 * More specifically, fetches a value within the given object
3500 * <code>o</code> at the given offset, or (if <code>o</code> is
3501 * null) from the memory address whose numerical value is the
3502 * given offset. <p>
3503 *
3504 * The specification of this method is the same as {@link
3505 * #getLong(Object, long)} except that the offset does not need to
3506 * have been obtained from {@link #objectFieldOffset} on the
3507 * {@link java.lang.reflect.Field} of some Java field. The value
3508 * in memory is raw data, and need not correspond to any Java
3509 * variable. Unless <code>o</code> is null, the value accessed
3510 * must be entirely within the allocated object. The endianness
3511 * of the value in memory is the endianness of the native platform.
3512 *
3513 * <p> The read will be atomic with respect to the largest power
3514 * of two that divides the GCD of the offset and the storage size.
3515 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3516 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3517 * respectively. There are no other guarantees of atomicity.
3518 * <p>
3519 * 8-byte atomicity is only guaranteed on platforms on which
3520 * support atomic accesses to longs.
3521 *
3522 * @param o Java heap object in which the value resides, if any, else
3523 * null
3524 * @param offset The offset in bytes from the start of the object
3525 * @return the value fetched from the indicated object
3526 * @throws RuntimeException No defined exceptions are thrown, not even
3527 * {@link NullPointerException}
3528 * @since 9
3529 */
3530 @HotSpotIntrinsicCandidate
3531 public final long getLongUnaligned(Object o, long offset) {
3532 if ((offset & 7) == 0) {
3533 return getLong(o, offset);
3534 } else if ((offset & 3) == 0) {
3535 return makeLong(getInt(o, offset),
3536 getInt(o, offset + 4));
3537 } else if ((offset & 1) == 0) {
3538 return makeLong(getShort(o, offset),
3539 getShort(o, offset + 2),
3540 getShort(o, offset + 4),
3541 getShort(o, offset + 6));
3542 } else {
3543 return makeLong(getByte(o, offset),
3544 getByte(o, offset + 1),
3545 getByte(o, offset + 2),
3546 getByte(o, offset + 3),
3547 getByte(o, offset + 4),
3548 getByte(o, offset + 5),
3549 getByte(o, offset + 6),
3550 getByte(o, offset + 7));
3551 }
3552 }
3553 /**
3554 * As {@link #getLongUnaligned(Object, long)} but with an
3555 * additional argument which specifies the endianness of the value
3556 * as stored in memory.
3557 *
3558 * @param o Java heap object in which the variable resides
3559 * @param offset The offset in bytes from the start of the object
3560 * @param bigEndian The endianness of the value
3561 * @return the value fetched from the indicated object
3562 * @since 9
3563 */
3564 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3565 return convEndian(bigEndian, getLongUnaligned(o, offset));
3566 }
3567
3568 /** @see #getLongUnaligned(Object, long) */
3569 @HotSpotIntrinsicCandidate
3570 public final int getIntUnaligned(Object o, long offset) {
3571 if ((offset & 3) == 0) {
3572 return getInt(o, offset);
3573 } else if ((offset & 1) == 0) {
3574 return makeInt(getShort(o, offset),
3575 getShort(o, offset + 2));
3576 } else {
3577 return makeInt(getByte(o, offset),
3578 getByte(o, offset + 1),
3579 getByte(o, offset + 2),
3580 getByte(o, offset + 3));
3581 }
3582 }
3583 /** @see #getLongUnaligned(Object, long, boolean) */
3584 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3585 return convEndian(bigEndian, getIntUnaligned(o, offset));
3586 }
3587
3588 /** @see #getLongUnaligned(Object, long) */
3589 @HotSpotIntrinsicCandidate
3590 public final short getShortUnaligned(Object o, long offset) {
3591 if ((offset & 1) == 0) {
3592 return getShort(o, offset);
3593 } else {
3594 return makeShort(getByte(o, offset),
3595 getByte(o, offset + 1));
3596 }
3597 }
3598 /** @see #getLongUnaligned(Object, long, boolean) */
3599 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3600 return convEndian(bigEndian, getShortUnaligned(o, offset));
3601 }
3602
3603 /** @see #getLongUnaligned(Object, long) */
3604 @HotSpotIntrinsicCandidate
3605 public final char getCharUnaligned(Object o, long offset) {
3606 if ((offset & 1) == 0) {
3607 return getChar(o, offset);
3608 } else {
3609 return (char)makeShort(getByte(o, offset),
3610 getByte(o, offset + 1));
3611 }
3612 }
3613
3614 /** @see #getLongUnaligned(Object, long, boolean) */
3615 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3616 return convEndian(bigEndian, getCharUnaligned(o, offset));
3617 }
3618
3619 /**
3620 * Stores a value at some byte offset into a given Java object.
3621 * <p>
3622 * The specification of this method is the same as {@link
3623 * #getLong(Object, long)} except that the offset does not need to
3624 * have been obtained from {@link #objectFieldOffset} on the
3625 * {@link java.lang.reflect.Field} of some Java field. The value
3626 * in memory is raw data, and need not correspond to any Java
3627 * variable. The endianness of the value in memory is the
3628 * endianness of the native platform.
3629 * <p>
3630 * The write will be atomic with respect to the largest power of
3631 * two that divides the GCD of the offset and the storage size.
3632 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3633 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3634 * respectively. There are no other guarantees of atomicity.
3635 * <p>
3636 * 8-byte atomicity is only guaranteed on platforms on which
3637 * support atomic accesses to longs.
3638 *
3639 * @param o Java heap object in which the value resides, if any, else
3640 * null
3641 * @param offset The offset in bytes from the start of the object
3642 * @param x the value to store
3643 * @throws RuntimeException No defined exceptions are thrown, not even
3644 * {@link NullPointerException}
3645 * @since 9
3646 */
3647 @HotSpotIntrinsicCandidate
3648 public final void putLongUnaligned(Object o, long offset, long x) {
3649 if ((offset & 7) == 0) {
3650 putLong(o, offset, x);
3651 } else if ((offset & 3) == 0) {
3652 putLongParts(o, offset,
3653 (int)(x >> 0),
3654 (int)(x >>> 32));
3655 } else if ((offset & 1) == 0) {
3656 putLongParts(o, offset,
3657 (short)(x >>> 0),
3658 (short)(x >>> 16),
3659 (short)(x >>> 32),
3660 (short)(x >>> 48));
3661 } else {
3662 putLongParts(o, offset,
3663 (byte)(x >>> 0),
3664 (byte)(x >>> 8),
3665 (byte)(x >>> 16),
3666 (byte)(x >>> 24),
3667 (byte)(x >>> 32),
3668 (byte)(x >>> 40),
3669 (byte)(x >>> 48),
3670 (byte)(x >>> 56));
3671 }
3672 }
3673
3674 /**
3675 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3676 * argument which specifies the endianness of the value as stored in memory.
3677 * @param o Java heap object in which the value resides
3678 * @param offset The offset in bytes from the start of the object
3679 * @param x the value to store
3680 * @param bigEndian The endianness of the value
3681 * @throws RuntimeException No defined exceptions are thrown, not even
3682 * {@link NullPointerException}
3683 * @since 9
3684 */
3685 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3686 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3687 }
3688
3689 /** @see #putLongUnaligned(Object, long, long) */
3690 @HotSpotIntrinsicCandidate
3691 public final void putIntUnaligned(Object o, long offset, int x) {
3692 if ((offset & 3) == 0) {
3693 putInt(o, offset, x);
3694 } else if ((offset & 1) == 0) {
3695 putIntParts(o, offset,
3696 (short)(x >> 0),
3697 (short)(x >>> 16));
3698 } else {
3699 putIntParts(o, offset,
3700 (byte)(x >>> 0),
3701 (byte)(x >>> 8),
3702 (byte)(x >>> 16),
3703 (byte)(x >>> 24));
3704 }
3705 }
3706 /** @see #putLongUnaligned(Object, long, long, boolean) */
3707 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3708 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3709 }
3710
3711 /** @see #putLongUnaligned(Object, long, long) */
3712 @HotSpotIntrinsicCandidate
3713 public final void putShortUnaligned(Object o, long offset, short x) {
3714 if ((offset & 1) == 0) {
3715 putShort(o, offset, x);
3716 } else {
3717 putShortParts(o, offset,
3718 (byte)(x >>> 0),
3719 (byte)(x >>> 8));
3720 }
3721 }
3722 /** @see #putLongUnaligned(Object, long, long, boolean) */
3723 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3724 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3725 }
3726
3727 /** @see #putLongUnaligned(Object, long, long) */
3728 @HotSpotIntrinsicCandidate
3729 public final void putCharUnaligned(Object o, long offset, char x) {
3730 putShortUnaligned(o, offset, (short)x);
3731 }
3732 /** @see #putLongUnaligned(Object, long, long, boolean) */
3733 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3734 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3735 }
3736
3737 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
3738
3739 // These methods construct integers from bytes. The byte ordering
3740 // is the native endianness of this platform.
3741 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3742 return ((toUnsignedLong(i0) << pickPos(56, 0))
3743 | (toUnsignedLong(i1) << pickPos(56, 8))
3744 | (toUnsignedLong(i2) << pickPos(56, 16))
3745 | (toUnsignedLong(i3) << pickPos(56, 24))
3746 | (toUnsignedLong(i4) << pickPos(56, 32))
3747 | (toUnsignedLong(i5) << pickPos(56, 40))
3748 | (toUnsignedLong(i6) << pickPos(56, 48))
3749 | (toUnsignedLong(i7) << pickPos(56, 56)));
3750 }
3751 private static long makeLong(short i0, short i1, short i2, short i3) {
3752 return ((toUnsignedLong(i0) << pickPos(48, 0))
3753 | (toUnsignedLong(i1) << pickPos(48, 16))
3754 | (toUnsignedLong(i2) << pickPos(48, 32))
3755 | (toUnsignedLong(i3) << pickPos(48, 48)));
3756 }
3757 private static long makeLong(int i0, int i1) {
3758 return (toUnsignedLong(i0) << pickPos(32, 0))
3759 | (toUnsignedLong(i1) << pickPos(32, 32));
3760 }
3761 private static int makeInt(short i0, short i1) {
3762 return (toUnsignedInt(i0) << pickPos(16, 0))
3763 | (toUnsignedInt(i1) << pickPos(16, 16));
3764 }
3765 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3766 return ((toUnsignedInt(i0) << pickPos(24, 0))
3767 | (toUnsignedInt(i1) << pickPos(24, 8))
3768 | (toUnsignedInt(i2) << pickPos(24, 16))
3769 | (toUnsignedInt(i3) << pickPos(24, 24)));
3770 }
3771 private static short makeShort(byte i0, byte i1) {
3772 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3773 | (toUnsignedInt(i1) << pickPos(8, 8)));
3774 }
3775
3776 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
3777 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
3778 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
3779
3780 // These methods write integers to memory from smaller parts
3781 // provided by their caller. The ordering in which these parts
3782 // are written is the native endianness of this platform.
3783 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3784 putByte(o, offset + 0, pick(i0, i7));
3785 putByte(o, offset + 1, pick(i1, i6));
3786 putByte(o, offset + 2, pick(i2, i5));
3787 putByte(o, offset + 3, pick(i3, i4));
3788 putByte(o, offset + 4, pick(i4, i3));
3789 putByte(o, offset + 5, pick(i5, i2));
3790 putByte(o, offset + 6, pick(i6, i1));
3791 putByte(o, offset + 7, pick(i7, i0));
3792 }
3793 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3794 putShort(o, offset + 0, pick(i0, i3));
3795 putShort(o, offset + 2, pick(i1, i2));
3796 putShort(o, offset + 4, pick(i2, i1));
3797 putShort(o, offset + 6, pick(i3, i0));
3798 }
3799 private void putLongParts(Object o, long offset, int i0, int i1) {
3800 putInt(o, offset + 0, pick(i0, i1));
3801 putInt(o, offset + 4, pick(i1, i0));
3802 }
3803 private void putIntParts(Object o, long offset, short i0, short i1) {
3804 putShort(o, offset + 0, pick(i0, i1));
3805 putShort(o, offset + 2, pick(i1, i0));
3806 }
3807 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3808 putByte(o, offset + 0, pick(i0, i3));
3809 putByte(o, offset + 1, pick(i1, i2));
3810 putByte(o, offset + 2, pick(i2, i1));
3811 putByte(o, offset + 3, pick(i3, i0));
3812 }
3813 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3814 putByte(o, offset + 0, pick(i0, i1));
3815 putByte(o, offset + 1, pick(i1, i0));
3816 }
3817
3818 // Zero-extend an integer
3819 private static int toUnsignedInt(byte n) { return n & 0xff; }
3820 private static int toUnsignedInt(short n) { return n & 0xffff; }
3821 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3822 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3823 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3824
3825 // Maybe byte-reverse an integer
3826 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
3827 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
3828 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
3829 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
3830
3831
3832
3833 private native long allocateMemory0(long bytes);
3834 private native long reallocateMemory0(long address, long bytes);
3835 private native void freeMemory0(long address);
3836 private native void setMemory0(Object o, long offset, long bytes, byte value);
3837 @HotSpotIntrinsicCandidate
3838 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3839 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3840 private native long objectFieldOffset0(Field f);
3841 private native long objectFieldOffset1(Class<?> c, String name);
3842 private native long staticFieldOffset0(Field f);
3843 private native Object staticFieldBase0(Field f);
3844 private native boolean shouldBeInitialized0(Class<?> c);
3845 private native void ensureClassInitialized0(Class<?> c);
3846 private native int arrayBaseOffset0(Class<?> arrayClass);
3847 private native int arrayIndexScale0(Class<?> arrayClass);
3848 private native Class<?> defineAnonymousClass0(Class<?> hostClass, byte[] data, Object[] cpPatches);
3849 private native int getLoadAverage0(double[] loadavg, int nelems);
3850
3851
3852 /**
3853 * Invokes the given direct byte buffer's cleaner, if any.
3854 *
3855 * @param directBuffer a direct byte buffer
3856 * @throws NullPointerException if {@code directBuffer} is null
3857 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
3858 * or is a {@link java.nio.Buffer#slice slice}, or is a
3859 * {@link java.nio.Buffer#duplicate duplicate}
3860 */
3861 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
3862 if (!directBuffer.isDirect())
3863 throw new IllegalArgumentException("buffer is non-direct");
3864
3865 DirectBuffer db = (DirectBuffer) directBuffer;
3866 if (db.attachment() != null)
3867 throw new IllegalArgumentException("duplicate or slice");
3868
3869 Cleaner cleaner = db.cleaner();
3870 if (cleaner != null) {
3871 cleaner.clean();
3872 }
3873 }
3874
3875 // The following deprecated methods are used by JSR 166.
3876
3877 @Deprecated(since="12", forRemoval=true)
3878 public final Object getObject(Object o, long offset) {
3879 return getReference(o, offset);
3880 }
3881 @Deprecated(since="12", forRemoval=true)
3882 public final Object getObjectVolatile(Object o, long offset) {
3883 return getReferenceVolatile(o, offset);
3884 }
3885 @Deprecated(since="12", forRemoval=true)
3886 public final Object getObjectAcquire(Object o, long offset) {
3887 return getReferenceAcquire(o, offset);
3888 }
3889 @Deprecated(since="12", forRemoval=true)
3890 public final Object getObjectOpaque(Object o, long offset) {
3891 return getReferenceOpaque(o, offset);
3892 }
3893
3894
3895 @Deprecated(since="12", forRemoval=true)
3896 public final void putObject(Object o, long offset, Object x) {
3897 putReference(o, offset, x);
3898 }
3899 @Deprecated(since="12", forRemoval=true)
3900 public final void putObjectVolatile(Object o, long offset, Object x) {
3901 putReferenceVolatile(o, offset, x);
3902 }
3903 @Deprecated(since="12", forRemoval=true)
3904 public final void putObjectOpaque(Object o, long offset, Object x) {
3905 putReferenceOpaque(o, offset, x);
3906 }
3907 @Deprecated(since="12", forRemoval=true)
3908 public final void putObjectRelease(Object o, long offset, Object x) {
3909 putReferenceRelease(o, offset, x);
3910 }
3911
3912
3913 @Deprecated(since="12", forRemoval=true)
3914 public final Object getAndSetObject(Object o, long offset, Object newValue) {
3915 return getAndSetReference(o, offset, newValue);
3916 }
3917 @Deprecated(since="12", forRemoval=true)
3918 public final Object getAndSetObjectAcquire(Object o, long offset, Object newValue) {
3919 return getAndSetReferenceAcquire(o, offset, newValue);
3920 }
3921 @Deprecated(since="12", forRemoval=true)
3922 public final Object getAndSetObjectRelease(Object o, long offset, Object newValue) {
3923 return getAndSetReferenceRelease(o, offset, newValue);
3924 }
3925
3926
3927 @Deprecated(since="12", forRemoval=true)
3928 public final boolean compareAndSetObject(Object o, long offset, Object expected, Object x) {
3929 return compareAndSetReference(o, offset, expected, x);
3930 }
3931 @Deprecated(since="12", forRemoval=true)
3932 public final Object compareAndExchangeObject(Object o, long offset, Object expected, Object x) {
3933 return compareAndExchangeReference(o, offset, expected, x);
3934 }
3935 @Deprecated(since="12", forRemoval=true)
3936 public final Object compareAndExchangeObjectAcquire(Object o, long offset, Object expected, Object x) {
3937 return compareAndExchangeReferenceAcquire(o, offset, expected, x);
3938 }
3939 @Deprecated(since="12", forRemoval=true)
3940 public final Object compareAndExchangeObjectRelease(Object o, long offset, Object expected, Object x) {
3941 return compareAndExchangeReferenceRelease(o, offset, expected, x);
3942 }
3943
3944
3945 @Deprecated(since="12", forRemoval=true)
3946 public final boolean weakCompareAndSetObject(Object o, long offset, Object expected, Object x) {
3947 return weakCompareAndSetReference(o, offset, expected, x);
3948 }
3949 @Deprecated(since="12", forRemoval=true)
3950 public final boolean weakCompareAndSetObjectAcquire(Object o, long offset, Object expected, Object x) {
3951 return weakCompareAndSetReferenceAcquire(o, offset, expected, x);
3952 }
3953 @Deprecated(since="12", forRemoval=true)
3954 public final boolean weakCompareAndSetObjectPlain(Object o, long offset, Object expected, Object x) {
3955 return weakCompareAndSetReferencePlain(o, offset, expected, x);
3956 }
3957 @Deprecated(since="12", forRemoval=true)
3958 public final boolean weakCompareAndSetObjectRelease(Object o, long offset, Object expected, Object x) {
3959 return weakCompareAndSetReferenceRelease(o, offset, expected, x);
3960 }
3961 }