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