1 /*
2 * Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.misc;
27
28 import jdk.internal.HotSpotIntrinsicCandidate;
29 import jdk.internal.vm.annotation.ForceInline;
30
31 import java.lang.reflect.Field;
32 import java.security.ProtectionDomain;
33
34
35 /**
36 * A collection of methods for performing low-level, unsafe operations.
37 * Although the class and all methods are public, use of this class is
38 * limited because only trusted code can obtain instances of it.
39 *
40 * <em>Note:</em> It is the resposibility of the caller to make sure
41 * arguments are checked before methods of this class are
42 * called. While some rudimentary checks are performed on the input,
43 * the checks are best effort and when performance is an overriding
44 * priority, as when methods of this class are optimized by the
45 * runtime compiler, some or all checks (if any) may be elided. Hence,
46 * the caller must not rely on the checks and corresponding
47 * exceptions!
48 *
49 * @author John R. Rose
50 * @see #getUnsafe
51 */
52
53 public final class Unsafe {
54
55 private static native void registerNatives();
56 static {
57 registerNatives();
58 }
59
60 private Unsafe() {}
61
62 private static final Unsafe theUnsafe = new Unsafe();
63
64 /**
65 * Provides the caller with the capability of performing unsafe
66 * operations.
67 *
68 * <p>The returned {@code Unsafe} object should be carefully guarded
69 * by the caller, since it can be used to read and write data at arbitrary
70 * memory addresses. It must never be passed to untrusted code.
71 *
72 * <p>Most methods in this class are very low-level, and correspond to a
73 * small number of hardware instructions (on typical machines). Compilers
74 * are encouraged to optimize these methods accordingly.
75 *
76 * <p>Here is a suggested idiom for using unsafe operations:
77 *
78 * <pre> {@code
79 * class MyTrustedClass {
80 * private static final Unsafe unsafe = Unsafe.getUnsafe();
81 * ...
82 * private long myCountAddress = ...;
83 * public int getCount() { return unsafe.getByte(myCountAddress); }
84 * }}</pre>
85 *
86 * (It may assist compilers to make the local variable {@code final}.)
87 */
88 public static Unsafe getUnsafe() {
89 return theUnsafe;
90 }
91
92 /// peek and poke operations
93 /// (compilers should optimize these to memory ops)
94
95 // These work on object fields in the Java heap.
96 // They will not work on elements of packed arrays.
97
98 /**
99 * Fetches a value from a given Java variable.
100 * More specifically, fetches a field or array element within the given
101 * object {@code o} at the given offset, or (if {@code o} is null)
102 * from the memory address whose numerical value is the given offset.
103 * <p>
104 * The results are undefined unless one of the following cases is true:
105 * <ul>
106 * <li>The offset was obtained from {@link #objectFieldOffset} on
107 * the {@link java.lang.reflect.Field} of some Java field and the object
108 * referred to by {@code o} is of a class compatible with that
109 * field's class.
110 *
111 * <li>The offset and object reference {@code o} (either null or
112 * non-null) were both obtained via {@link #staticFieldOffset}
113 * and {@link #staticFieldBase} (respectively) from the
114 * reflective {@link Field} representation of some Java field.
115 *
116 * <li>The object referred to by {@code o} is an array, and the offset
117 * is an integer of the form {@code B+N*S}, where {@code N} is
118 * a valid index into the array, and {@code B} and {@code S} are
119 * the values obtained by {@link #arrayBaseOffset} and {@link
120 * #arrayIndexScale} (respectively) from the array's class. The value
121 * referred to is the {@code N}<em>th</em> element of the array.
122 *
123 * </ul>
124 * <p>
125 * If one of the above cases is true, the call references a specific Java
126 * variable (field or array element). However, the results are undefined
127 * if that variable is not in fact of the type returned by this method.
128 * <p>
129 * This method refers to a variable by means of two parameters, and so
130 * it provides (in effect) a <em>double-register</em> addressing mode
131 * for Java variables. When the object reference is null, this method
132 * uses its offset as an absolute address. This is similar in operation
133 * to methods such as {@link #getInt(long)}, which provide (in effect) a
134 * <em>single-register</em> addressing mode for non-Java variables.
135 * However, because Java variables may have a different layout in memory
136 * from non-Java variables, programmers should not assume that these
137 * two addressing modes are ever equivalent. Also, programmers should
138 * remember that offsets from the double-register addressing mode cannot
139 * be portably confused with longs used in the single-register addressing
140 * mode.
141 *
142 * @param o Java heap object in which the variable resides, if any, else
143 * null
144 * @param offset indication of where the variable resides in a Java heap
145 * object, if any, else a memory address locating the variable
146 * statically
147 * @return the value fetched from the indicated Java variable
148 * @throws RuntimeException No defined exceptions are thrown, not even
149 * {@link NullPointerException}
150 */
151 @HotSpotIntrinsicCandidate
152 public native int getInt(Object o, long offset);
153
154 /**
155 * Stores a value into a given Java variable.
156 * <p>
157 * The first two parameters are interpreted exactly as with
158 * {@link #getInt(Object, long)} to refer to a specific
159 * Java variable (field or array element). The given value
160 * is stored into that variable.
161 * <p>
162 * The variable must be of the same type as the method
163 * parameter {@code x}.
164 *
165 * @param o Java heap object in which the variable resides, if any, else
166 * null
167 * @param offset indication of where the variable resides in a Java heap
168 * object, if any, else a memory address locating the variable
169 * statically
170 * @param x the value to store into the indicated Java variable
171 * @throws RuntimeException No defined exceptions are thrown, not even
172 * {@link NullPointerException}
173 */
174 @HotSpotIntrinsicCandidate
175 public native void putInt(Object o, long offset, int x);
176
177 /**
178 * Fetches a reference value from a given Java variable.
179 * @see #getInt(Object, long)
180 */
181 @HotSpotIntrinsicCandidate
182 public native Object getObject(Object o, long offset);
183
184 /**
185 * Stores a reference value into a given Java variable.
186 * <p>
187 * Unless the reference {@code x} being stored is either null
188 * or matches the field type, the results are undefined.
189 * If the reference {@code o} is non-null, card marks or
190 * other store barriers for that object (if the VM requires them)
191 * are updated.
192 * @see #putInt(Object, long, int)
193 */
194 @HotSpotIntrinsicCandidate
195 public native void putObject(Object o, long offset, Object x);
196
197 /** @see #getInt(Object, long) */
198 @HotSpotIntrinsicCandidate
199 public native boolean getBoolean(Object o, long offset);
200
201 /** @see #putInt(Object, long, int) */
202 @HotSpotIntrinsicCandidate
203 public native void putBoolean(Object o, long offset, boolean x);
204
205 /** @see #getInt(Object, long) */
206 @HotSpotIntrinsicCandidate
207 public native byte getByte(Object o, long offset);
208
209 /** @see #putInt(Object, long, int) */
210 @HotSpotIntrinsicCandidate
211 public native void putByte(Object o, long offset, byte x);
212
213 /** @see #getInt(Object, long) */
214 @HotSpotIntrinsicCandidate
215 public native short getShort(Object o, long offset);
216
217 /** @see #putInt(Object, long, int) */
218 @HotSpotIntrinsicCandidate
219 public native void putShort(Object o, long offset, short x);
220
221 /** @see #getInt(Object, long) */
222 @HotSpotIntrinsicCandidate
223 public native char getChar(Object o, long offset);
224
225 /** @see #putInt(Object, long, int) */
226 @HotSpotIntrinsicCandidate
227 public native void putChar(Object o, long offset, char x);
228
229 /** @see #getInt(Object, long) */
230 @HotSpotIntrinsicCandidate
231 public native long getLong(Object o, long offset);
232
233 /** @see #putInt(Object, long, int) */
234 @HotSpotIntrinsicCandidate
235 public native void putLong(Object o, long offset, long x);
236
237 /** @see #getInt(Object, long) */
238 @HotSpotIntrinsicCandidate
239 public native float getFloat(Object o, long offset);
240
241 /** @see #putInt(Object, long, int) */
242 @HotSpotIntrinsicCandidate
243 public native void putFloat(Object o, long offset, float x);
244
245 /** @see #getInt(Object, long) */
246 @HotSpotIntrinsicCandidate
247 public native double getDouble(Object o, long offset);
248
249 /** @see #putInt(Object, long, int) */
250 @HotSpotIntrinsicCandidate
251 public native void putDouble(Object o, long offset, double x);
252
253 /**
254 * Fetches a native pointer from a given memory address. If the address is
255 * zero, or does not point into a block obtained from {@link
256 * #allocateMemory}, the results are undefined.
257 *
258 * <p>If the native pointer is less than 64 bits wide, it is extended as
259 * an unsigned number to a Java long. The pointer may be indexed by any
260 * given byte offset, simply by adding that offset (as a simple integer) to
261 * the long representing the pointer. The number of bytes actually read
262 * from the target address may be determined by consulting {@link
263 * #addressSize}.
264 *
265 * @see #allocateMemory
266 * @see #getInt(Object, long)
267 */
268 @ForceInline
269 public long getAddress(Object o, long offset) {
270 if (ADDRESS_SIZE == 4) {
271 return Integer.toUnsignedLong(getInt(o, offset));
272 } else {
273 return getLong(o, offset);
274 }
275 }
276
277 /**
278 * Stores a native pointer into a given memory address. If the address is
279 * zero, or does not point into a block obtained from {@link
280 * #allocateMemory}, the results are undefined.
281 *
282 * <p>The number of bytes actually written at the target address may be
283 * determined by consulting {@link #addressSize}.
284 *
285 * @see #allocateMemory
286 * @see #putInt(Object, long, int)
287 */
288 @ForceInline
289 public void putAddress(Object o, long offset, long x) {
290 if (ADDRESS_SIZE == 4) {
291 putInt(o, offset, (int)x);
292 } else {
293 putLong(o, offset, x);
294 }
295 }
296
297 // These read VM internal data.
298
299 /**
300 * Fetches an uncompressed reference value from a given native variable
301 * ignoring the VM's compressed references mode.
302 *
303 * @param address a memory address locating the variable
304 * @return the value fetched from the indicated native variable
305 */
306 public native Object getUncompressedObject(long address);
307
308 // These work on values in the C heap.
309
310 /**
311 * Fetches a value from a given memory address. If the address is zero, or
312 * does not point into a block obtained from {@link #allocateMemory}, the
313 * results are undefined.
314 *
315 * @see #allocateMemory
316 */
317 @ForceInline
318 public byte getByte(long address) {
319 return getByte(null, address);
320 }
321
322 /**
323 * Stores a value into a given memory address. If the address is zero, or
324 * does not point into a block obtained from {@link #allocateMemory}, the
325 * results are undefined.
326 *
327 * @see #getByte(long)
328 */
329 @ForceInline
330 public void putByte(long address, byte x) {
331 putByte(null, address, x);
332 }
333
334 /** @see #getByte(long) */
335 @ForceInline
336 public short getShort(long address) {
337 return getShort(null, address);
338 }
339
340 /** @see #putByte(long, byte) */
341 @ForceInline
342 public void putShort(long address, short x) {
343 putShort(null, address, x);
344 }
345
346 /** @see #getByte(long) */
347 @ForceInline
348 public char getChar(long address) {
349 return getChar(null, address);
350 }
351
352 /** @see #putByte(long, byte) */
353 @ForceInline
354 public void putChar(long address, char x) {
355 putChar(null, address, x);
356 }
357
358 /** @see #getByte(long) */
359 @ForceInline
360 public int getInt(long address) {
361 return getInt(null, address);
362 }
363
364 /** @see #putByte(long, byte) */
365 @ForceInline
366 public void putInt(long address, int x) {
367 putInt(null, address, x);
368 }
369
370 /** @see #getByte(long) */
371 @ForceInline
372 public long getLong(long address) {
373 return getLong(null, address);
374 }
375
376 /** @see #putByte(long, byte) */
377 @ForceInline
378 public void putLong(long address, long x) {
379 putLong(null, address, x);
380 }
381
382 /** @see #getByte(long) */
383 @ForceInline
384 public float getFloat(long address) {
385 return getFloat(null, address);
386 }
387
388 /** @see #putByte(long, byte) */
389 @ForceInline
390 public void putFloat(long address, float x) {
391 putFloat(null, address, x);
392 }
393
394 /** @see #getByte(long) */
395 @ForceInline
396 public double getDouble(long address) {
397 return getDouble(null, address);
398 }
399
400 /** @see #putByte(long, byte) */
401 @ForceInline
402 public void putDouble(long address, double x) {
403 putDouble(null, address, x);
404 }
405
406 /** @see #getAddress(Object, long) */
407 @ForceInline
408 public long getAddress(long address) {
409 return getAddress(null, address);
410 }
411
412 /** @see #putAddress(Object, long, long) */
413 @ForceInline
414 public void putAddress(long address, long x) {
415 putAddress(null, address, x);
416 }
417
418
419
420 /// helper methods for validating various types of objects/values
421
422 /**
423 * Create an exception reflecting that some of the input was invalid
424 *
425 * <em>Note:</em> It is the resposibility of the caller to make
426 * sure arguments are checked before the methods are called. While
427 * some rudimentary checks are performed on the input, the checks
428 * are best effort and when performance is an overriding priority,
429 * as when methods of this class are optimized by the runtime
430 * compiler, some or all checks (if any) may be elided. Hence, the
431 * caller must not rely on the checks and corresponding
432 * exceptions!
433 *
434 * @return an exception object
435 */
436 private RuntimeException invalidInput() {
437 return new IllegalArgumentException();
438 }
439
440 /**
441 * Check if a value is 32-bit clean (32 MSB are all zero)
442 *
443 * @param value the 64-bit value to check
444 *
445 * @return true if the value is 32-bit clean
446 */
447 private boolean is32BitClean(long value) {
448 return value >>> 32 == 0;
449 }
450
451 /**
452 * Check the validity of a size (the equivalent of a size_t)
453 *
454 * @throws RuntimeException if the size is invalid
455 * (<em>Note:</em> after optimization, invalid inputs may
456 * go undetected, which will lead to unpredictable
457 * behavior)
458 */
459 private void checkSize(long size) {
460 if (ADDRESS_SIZE == 4) {
461 // Note: this will also check for negative sizes
462 if (!is32BitClean(size)) {
463 throw invalidInput();
464 }
465 } else if (size < 0) {
466 throw invalidInput();
467 }
468 }
469
470 /**
471 * Check the validity of a native address (the equivalent of void*)
472 *
473 * @throws RuntimeException if the address is invalid
474 * (<em>Note:</em> after optimization, invalid inputs may
475 * go undetected, which will lead to unpredictable
476 * behavior)
477 */
478 private void checkNativeAddress(long address) {
479 if (ADDRESS_SIZE == 4) {
480 // Accept both zero and sign extended pointers. A valid
481 // pointer will, after the +1 below, either have produced
482 // the value 0x0 or 0x1. Masking off the low bit allows
483 // for testing against 0.
484 if ((((address >> 32) + 1) & ~1) != 0) {
485 throw invalidInput();
486 }
487 }
488 }
489
490 /**
491 * Check the validity of an offset, relative to a base object
492 *
493 * @param o the base object
494 * @param offset the offset to check
495 *
496 * @throws RuntimeException if the size is invalid
497 * (<em>Note:</em> after optimization, invalid inputs may
498 * go undetected, which will lead to unpredictable
499 * behavior)
500 */
501 private void checkOffset(Object o, long offset) {
502 if (ADDRESS_SIZE == 4) {
503 // Note: this will also check for negative offsets
504 if (!is32BitClean(offset)) {
505 throw invalidInput();
506 }
507 } else if (offset < 0) {
508 throw invalidInput();
509 }
510 }
511
512 /**
513 * Check the validity of a double-register pointer
514 *
515 * Note: This code deliberately does *not* check for NPE for (at
516 * least) three reasons:
517 *
518 * 1) NPE is not just NULL/0 - there is a range of values all
519 * resulting in an NPE, which is not trivial to check for
520 *
521 * 2) It is the responsibility of the callers of Unsafe methods
522 * to verify the input, so throwing an exception here is not really
523 * useful - passing in a NULL pointer is a critical error and the
524 * must not expect an exception to be thrown anyway.
525 *
526 * 3) the actual operations will detect NULL pointers anyway by
527 * means of traps and signals (like SIGSEGV).
528 *
529 * @param o Java heap object, or null
530 * @param offset indication of where the variable resides in a Java heap
531 * object, if any, else a memory address locating the variable
532 * statically
533 *
534 * @throws RuntimeException if the pointer is invalid
535 * (<em>Note:</em> after optimization, invalid inputs may
536 * go undetected, which will lead to unpredictable
537 * behavior)
538 */
539 private void checkPointer(Object o, long offset) {
540 if (o == null) {
541 checkNativeAddress(offset);
542 } else {
543 checkOffset(o, offset);
544 }
545 }
546
547 /**
548 * Check if a type is a primitive array type
549 *
550 * @param c the type to check
551 *
552 * @return true if the type is a primitive array type
553 */
554 private void checkPrimitiveArray(Class<?> c) {
555 Class<?> componentType = c.getComponentType();
556 if (componentType == null || !componentType.isPrimitive()) {
557 throw invalidInput();
558 }
559 }
560
561 /**
562 * Check that a pointer is a valid primitive array type pointer
563 *
564 * Note: pointers off-heap are considered to be primitive arrays
565 *
566 * @throws RuntimeException if the pointer is invalid
567 * (<em>Note:</em> after optimization, invalid inputs may
568 * go undetected, which will lead to unpredictable
569 * behavior)
570 */
571 private void checkPrimitivePointer(Object o, long offset) {
572 checkPointer(o, offset);
573
574 if (o != null) {
575 // If on heap, it must be a primitive array
576 checkPrimitiveArray(o.getClass());
577 }
578 }
579
580
581 /// wrappers for malloc, realloc, free:
582
583 /**
584 * Allocates a new block of native memory, of the given size in bytes. The
585 * contents of the memory are uninitialized; they will generally be
586 * garbage. The resulting native pointer will never be zero, and will be
587 * aligned for all value types. Dispose of this memory by calling {@link
588 * #freeMemory}, or resize it with {@link #reallocateMemory}.
589 *
590 * <em>Note:</em> It is the resposibility of the caller to make
591 * sure arguments are checked before the methods are called. While
592 * some rudimentary checks are performed on the input, the checks
593 * are best effort and when performance is an overriding priority,
594 * as when methods of this class are optimized by the runtime
595 * compiler, some or all checks (if any) may be elided. Hence, the
596 * caller must not rely on the checks and corresponding
597 * exceptions!
598 *
599 * @throws RuntimeException if the size is negative or too large
600 * for the native size_t type
601 *
602 * @throws OutOfMemoryError if the allocation is refused by the system
603 *
604 * @see #getByte(long)
605 * @see #putByte(long, byte)
606 */
607 public long allocateMemory(long bytes) {
608 allocateMemoryChecks(bytes);
609
610 if (bytes == 0) {
611 return 0;
612 }
613
614 long p = allocateMemory0(bytes);
615 if (p == 0) {
616 throw new OutOfMemoryError();
617 }
618
619 return p;
620 }
621
622 /**
623 * Validate the arguments to allocateMemory
624 *
625 * @throws RuntimeException if the arguments are invalid
626 * (<em>Note:</em> after optimization, invalid inputs may
627 * go undetected, which will lead to unpredictable
628 * behavior)
629 */
630 private void allocateMemoryChecks(long bytes) {
631 checkSize(bytes);
632 }
633
634 /**
635 * Resizes a new block of native memory, to the given size in bytes. The
636 * contents of the new block past the size of the old block are
637 * uninitialized; they will generally be garbage. The resulting native
638 * pointer will be zero if and only if the requested size is zero. The
639 * resulting native pointer will be aligned for all value types. Dispose
640 * of this memory by calling {@link #freeMemory}, or resize it with {@link
641 * #reallocateMemory}. The address passed to this method may be null, in
642 * which case an allocation will be performed.
643 *
644 * <em>Note:</em> It is the resposibility of the caller to make
645 * sure arguments are checked before the methods are called. While
646 * some rudimentary checks are performed on the input, the checks
647 * are best effort and when performance is an overriding priority,
648 * as when methods of this class are optimized by the runtime
649 * compiler, some or all checks (if any) may be elided. Hence, the
650 * caller must not rely on the checks and corresponding
651 * exceptions!
652 *
653 * @throws RuntimeException if the size is negative or too large
654 * for the native size_t type
655 *
656 * @throws OutOfMemoryError if the allocation is refused by the system
657 *
658 * @see #allocateMemory
659 */
660 public long reallocateMemory(long address, long bytes) {
661 reallocateMemoryChecks(address, bytes);
662
663 if (bytes == 0) {
664 freeMemory(address);
665 return 0;
666 }
667
668 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
669 if (p == 0) {
670 throw new OutOfMemoryError();
671 }
672
673 return p;
674 }
675
676 /**
677 * Validate the arguments to reallocateMemory
678 *
679 * @throws RuntimeException if the arguments are invalid
680 * (<em>Note:</em> after optimization, invalid inputs may
681 * go undetected, which will lead to unpredictable
682 * behavior)
683 */
684 private void reallocateMemoryChecks(long address, long bytes) {
685 checkPointer(null, address);
686 checkSize(bytes);
687 }
688
689 /**
690 * Sets all bytes in a given block of memory to a fixed value
691 * (usually zero).
692 *
693 * <p>This method determines a block's base address by means of two parameters,
694 * and so it provides (in effect) a <em>double-register</em> addressing mode,
695 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
696 * the offset supplies an absolute base address.
697 *
698 * <p>The stores are in coherent (atomic) units of a size determined
699 * by the address and length parameters. If the effective address and
700 * length are all even modulo 8, the stores take place in 'long' units.
701 * If the effective address and length are (resp.) even modulo 4 or 2,
702 * the stores take place in units of 'int' or 'short'.
703 *
704 * <em>Note:</em> It is the resposibility of the caller to make
705 * sure arguments are checked before the methods are called. While
706 * some rudimentary checks are performed on the input, the checks
707 * are best effort and when performance is an overriding priority,
708 * as when methods of this class are optimized by the runtime
709 * compiler, some or all checks (if any) may be elided. Hence, the
710 * caller must not rely on the checks and corresponding
711 * exceptions!
712 *
713 * @throws RuntimeException if any of the arguments is invalid
714 *
715 * @since 1.7
716 */
717 public void setMemory(Object o, long offset, long bytes, byte value) {
718 setMemoryChecks(o, offset, bytes, value);
719
720 if (bytes == 0) {
721 return;
722 }
723
724 setMemory0(o, offset, bytes, value);
725 }
726
727 /**
728 * Sets all bytes in a given block of memory to a fixed value
729 * (usually zero). This provides a <em>single-register</em> addressing mode,
730 * as discussed in {@link #getInt(Object,long)}.
731 *
732 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
733 */
734 public void setMemory(long address, long bytes, byte value) {
735 setMemory(null, address, bytes, value);
736 }
737
738 /**
739 * Validate the arguments to setMemory
740 *
741 * @throws RuntimeException if the arguments are invalid
742 * (<em>Note:</em> after optimization, invalid inputs may
743 * go undetected, which will lead to unpredictable
744 * behavior)
745 */
746 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
747 checkPrimitivePointer(o, offset);
748 checkSize(bytes);
749 }
750
751 /**
752 * Sets all bytes in a given block of memory to a copy of another
753 * block.
754 *
755 * <p>This method determines each block's base address by means of two parameters,
756 * and so it provides (in effect) a <em>double-register</em> addressing mode,
757 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
758 * the offset supplies an absolute base address.
759 *
760 * <p>The transfers are in coherent (atomic) units of a size determined
761 * by the address and length parameters. If the effective addresses and
762 * length are all even modulo 8, the transfer takes place in 'long' units.
763 * If the effective addresses and length are (resp.) even modulo 4 or 2,
764 * the transfer takes place in units of 'int' or 'short'.
765 *
766 * <em>Note:</em> It is the resposibility of the caller to make
767 * sure arguments are checked before the methods are called. While
768 * some rudimentary checks are performed on the input, the checks
769 * are best effort and when performance is an overriding priority,
770 * as when methods of this class are optimized by the runtime
771 * compiler, some or all checks (if any) may be elided. Hence, the
772 * caller must not rely on the checks and corresponding
773 * exceptions!
774 *
775 * @throws RuntimeException if any of the arguments is invalid
776 *
777 * @since 1.7
778 */
779 public void copyMemory(Object srcBase, long srcOffset,
780 Object destBase, long destOffset,
781 long bytes) {
782 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
783
784 if (bytes == 0) {
785 return;
786 }
787
788 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
789 }
790
791 /**
792 * Sets all bytes in a given block of memory to a copy of another
793 * block. This provides a <em>single-register</em> addressing mode,
794 * as discussed in {@link #getInt(Object,long)}.
795 *
796 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
797 */
798 public void copyMemory(long srcAddress, long destAddress, long bytes) {
799 copyMemory(null, srcAddress, null, destAddress, bytes);
800 }
801
802 /**
803 * Validate the arguments to copyMemory
804 *
805 * @throws RuntimeException if any of the arguments is invalid
806 * (<em>Note:</em> after optimization, invalid inputs may
807 * go undetected, which will lead to unpredictable
808 * behavior)
809 */
810 private void copyMemoryChecks(Object srcBase, long srcOffset,
811 Object destBase, long destOffset,
812 long bytes) {
813 checkSize(bytes);
814 checkPrimitivePointer(srcBase, srcOffset);
815 checkPrimitivePointer(destBase, destOffset);
816 }
817
818 /**
819 * Copies all elements from one block of memory to another block,
820 * *unconditionally* byte swapping the elements on the fly.
821 *
822 * <p>This method determines each block's base address by means of two parameters,
823 * and so it provides (in effect) a <em>double-register</em> addressing mode,
824 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
825 * the offset supplies an absolute base address.
826 *
827 * <em>Note:</em> It is the resposibility of the caller to make
828 * sure arguments are checked before the methods are called. While
829 * some rudimentary checks are performed on the input, the checks
830 * are best effort and when performance is an overriding priority,
831 * as when methods of this class are optimized by the runtime
832 * compiler, some or all checks (if any) may be elided. Hence, the
833 * caller must not rely on the checks and corresponding
834 * exceptions!
835 *
836 * @throws RuntimeException if any of the arguments is invalid
837 *
838 * @since 9
839 */
840 public void copySwapMemory(Object srcBase, long srcOffset,
841 Object destBase, long destOffset,
842 long bytes, long elemSize) {
843 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
844
845 if (bytes == 0) {
846 return;
847 }
848
849 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
850 }
851
852 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
853 Object destBase, long destOffset,
854 long bytes, long elemSize) {
855 checkSize(bytes);
856
857 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
858 throw invalidInput();
859 }
860 if (bytes % elemSize != 0) {
861 throw invalidInput();
862 }
863
864 checkPrimitivePointer(srcBase, srcOffset);
865 checkPrimitivePointer(destBase, destOffset);
866 }
867
868 /**
869 * Copies all elements from one block of memory to another block, byte swapping the
870 * elements on the fly.
871 *
872 * This provides a <em>single-register</em> addressing mode, as
873 * discussed in {@link #getInt(Object,long)}.
874 *
875 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
876 */
877 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
878 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
879 }
880
881 /**
882 * Disposes of a block of native memory, as obtained from {@link
883 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
884 * this method may be null, in which case no action is taken.
885 *
886 * <em>Note:</em> It is the resposibility of the caller to make
887 * sure arguments are checked before the methods are called. While
888 * some rudimentary checks are performed on the input, the checks
889 * are best effort and when performance is an overriding priority,
890 * as when methods of this class are optimized by the runtime
891 * compiler, some or all checks (if any) may be elided. Hence, the
892 * caller must not rely on the checks and corresponding
893 * exceptions!
894 *
895 * @throws RuntimeException if any of the arguments is invalid
896 *
897 * @see #allocateMemory
898 */
899 public void freeMemory(long address) {
900 freeMemoryChecks(address);
901
902 if (address == 0) {
903 return;
904 }
905
906 freeMemory0(address);
907 }
908
909 /**
910 * Validate the arguments to freeMemory
911 *
912 * @throws RuntimeException if the arguments are invalid
913 * (<em>Note:</em> after optimization, invalid inputs may
914 * go undetected, which will lead to unpredictable
915 * behavior)
916 */
917 private void freeMemoryChecks(long address) {
918 checkPointer(null, address);
919 }
920
921 /**
922 * ensure writeback of a specified virtual memory address range
923 * from cache to physical memory. all bytes in the address range
924 * are guaranteed to have been written back to physical memory on
925 * return from this call i.e. subsequently executed store
926 * instructions are guaranteed not to be visible before the
927 * writeback is completed.
928 *
929 * @param address
930 * the lowest byte address that must be guaranteed written
931 * back to memory. bytes at lower addresses may also be
932 * written back.
933 *
934 * @param length
935 * the length in bytes of the region starting at address
936 * that must be guaranteed written back to memory.
937 *
938 * @throws RuntimeException if the arguments are invalid
939 * (<em>Note:</em> after optimization, invalid inputs may
940 * go undetected, which will lead to unpredictable
941 * behavior)
942 */
943
944 public void writebackMemory(long address, long length)
945 {
946 checkWritebackMemory(address, length);
947
948 // perform any required pre-writeback barrier
949 writebackPreSync0();
950
951 // write back one cache line at a time
952 long line = (address & CACHE_LINE_MASK);
953 long end = address + length;
954 while (line < end) {
955 writeback0(line);
956 line += CACHE_LINE_FLUSH_SIZE;
957 }
958
959 // perform any required post-writeback barrier
960 writebackPostSync0();
961 }
962
963 /**
964 * Validate the arguments to writebackMemory
965 *
966 * @throws RuntimeException if the arguments are invalid
967 * (<em>Note:</em> after optimization, invalid inputs may
968 * go undetected, which will lead to unpredictable
969 * behavior)
970 */
971 private void checkWritebackMemory(long address, long length)
972 {
973 checkNativeAddress(address);
974 checkSize(length);
975 }
976
977 /**
978 * The size of an L1 data cache line which will be a power of two.
979 */
980 private static final long CACHE_LINE_FLUSH_SIZE = (long)theUnsafe.dataCacheLineFlushSize0();
981 private static final long CACHE_LINE_MASK = ~(CACHE_LINE_FLUSH_SIZE - 1);
982
983 /**
984 * primitive operation forcing writeback of a single cache line.
985 *
986 * @param address
987 * the start address of the cache line to be written back
988 */
989 // native used to write back an individual cache line starting at
990 // the supplied address
991 @HotSpotIntrinsicCandidate
992 private native void writeback0(long address);
993 // native used to serialise writeback operations relative to
994 // preceding memory writes
995 @HotSpotIntrinsicCandidate
996 private native void writebackPreSync0();
997 // native used to serialise writeback operations relative to
998 // following memory writes
999 @HotSpotIntrinsicCandidate
1000 private native void writebackPostSync0();
1001
1002 /// random queries
1003
1004 /**
1005 * This constant differs from all results that will ever be returned from
1006 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1007 * or {@link #arrayBaseOffset}.
1008 */
1009 public static final int INVALID_FIELD_OFFSET = -1;
1010
1011 /**
1012 * Reports the location of a given field in the storage allocation of its
1013 * class. Do not expect to perform any sort of arithmetic on this offset;
1014 * it is just a cookie which is passed to the unsafe heap memory accessors.
1015 *
1016 * <p>Any given field will always have the same offset and base, and no
1017 * two distinct fields of the same class will ever have the same offset
1018 * and base.
1019 *
1020 * <p>As of 1.4.1, offsets for fields are represented as long values,
1021 * although the Sun JVM does not use the most significant 32 bits.
1022 * However, JVM implementations which store static fields at absolute
1023 * addresses can use long offsets and null base pointers to express
1024 * the field locations in a form usable by {@link #getInt(Object,long)}.
1025 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1026 * must preserve all bits of static field offsets.
1027 * @see #getInt(Object, long)
1028 */
1029 public long objectFieldOffset(Field f) {
1030 if (f == null) {
1031 throw new NullPointerException();
1032 }
1033
1034 return objectFieldOffset0(f);
1035 }
1036
1037 /**
1038 * Reports the location of the field with a given name in the storage
1039 * allocation of its class.
1040 *
1041 * @throws NullPointerException if any parameter is {@code null}.
1042 * @throws InternalError if there is no field named {@code name} declared
1043 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)}
1044 * would throw {@code java.lang.NoSuchFieldException}.
1045 *
1046 * @see #objectFieldOffset(Field)
1047 */
1048 public long objectFieldOffset(Class<?> c, String name) {
1049 if (c == null || name == null) {
1050 throw new NullPointerException();
1051 }
1052
1053 return objectFieldOffset1(c, name);
1054 }
1055
1056 /**
1057 * Reports the location of a given static field, in conjunction with {@link
1058 * #staticFieldBase}.
1059 * <p>Do not expect to perform any sort of arithmetic on this offset;
1060 * it is just a cookie which is passed to the unsafe heap memory accessors.
1061 *
1062 * <p>Any given field will always have the same offset, and no two distinct
1063 * fields of the same class will ever have the same offset.
1064 *
1065 * <p>As of 1.4.1, offsets for fields are represented as long values,
1066 * although the Sun JVM does not use the most significant 32 bits.
1067 * It is hard to imagine a JVM technology which needs more than
1068 * a few bits to encode an offset within a non-array object,
1069 * However, for consistency with other methods in this class,
1070 * this method reports its result as a long value.
1071 * @see #getInt(Object, long)
1072 */
1073 public long staticFieldOffset(Field f) {
1074 if (f == null) {
1075 throw new NullPointerException();
1076 }
1077
1078 return staticFieldOffset0(f);
1079 }
1080
1081 /**
1082 * Reports the location of a given static field, in conjunction with {@link
1083 * #staticFieldOffset}.
1084 * <p>Fetch the base "Object", if any, with which static fields of the
1085 * given class can be accessed via methods like {@link #getInt(Object,
1086 * long)}. This value may be null. This value may refer to an object
1087 * which is a "cookie", not guaranteed to be a real Object, and it should
1088 * not be used in any way except as argument to the get and put routines in
1089 * this class.
1090 */
1091 public Object staticFieldBase(Field f) {
1092 if (f == null) {
1093 throw new NullPointerException();
1094 }
1095
1096 return staticFieldBase0(f);
1097 }
1098
1099 /**
1100 * Detects if the given class may need to be initialized. This is often
1101 * needed in conjunction with obtaining the static field base of a
1102 * class.
1103 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1104 */
1105 public boolean shouldBeInitialized(Class<?> c) {
1106 if (c == null) {
1107 throw new NullPointerException();
1108 }
1109
1110 return shouldBeInitialized0(c);
1111 }
1112
1113 /**
1114 * Ensures the given class has been initialized. This is often
1115 * needed in conjunction with obtaining the static field base of a
1116 * class.
1117 */
1118 public void ensureClassInitialized(Class<?> c) {
1119 if (c == null) {
1120 throw new NullPointerException();
1121 }
1122
1123 ensureClassInitialized0(c);
1124 }
1125
1126 /**
1127 * Reports the offset of the first element in the storage allocation of a
1128 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1129 * for the same class, you may use that scale factor, together with this
1130 * base offset, to form new offsets to access elements of arrays of the
1131 * given class.
1132 *
1133 * @see #getInt(Object, long)
1134 * @see #putInt(Object, long, int)
1135 */
1136 public int arrayBaseOffset(Class<?> arrayClass) {
1137 if (arrayClass == null) {
1138 throw new NullPointerException();
1139 }
1140
1141 return arrayBaseOffset0(arrayClass);
1142 }
1143
1144
1145 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1146 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1147 = theUnsafe.arrayBaseOffset(boolean[].class);
1148
1149 /** The value of {@code arrayBaseOffset(byte[].class)} */
1150 public static final int ARRAY_BYTE_BASE_OFFSET
1151 = theUnsafe.arrayBaseOffset(byte[].class);
1152
1153 /** The value of {@code arrayBaseOffset(short[].class)} */
1154 public static final int ARRAY_SHORT_BASE_OFFSET
1155 = theUnsafe.arrayBaseOffset(short[].class);
1156
1157 /** The value of {@code arrayBaseOffset(char[].class)} */
1158 public static final int ARRAY_CHAR_BASE_OFFSET
1159 = theUnsafe.arrayBaseOffset(char[].class);
1160
1161 /** The value of {@code arrayBaseOffset(int[].class)} */
1162 public static final int ARRAY_INT_BASE_OFFSET
1163 = theUnsafe.arrayBaseOffset(int[].class);
1164
1165 /** The value of {@code arrayBaseOffset(long[].class)} */
1166 public static final int ARRAY_LONG_BASE_OFFSET
1167 = theUnsafe.arrayBaseOffset(long[].class);
1168
1169 /** The value of {@code arrayBaseOffset(float[].class)} */
1170 public static final int ARRAY_FLOAT_BASE_OFFSET
1171 = theUnsafe.arrayBaseOffset(float[].class);
1172
1173 /** The value of {@code arrayBaseOffset(double[].class)} */
1174 public static final int ARRAY_DOUBLE_BASE_OFFSET
1175 = theUnsafe.arrayBaseOffset(double[].class);
1176
1177 /** The value of {@code arrayBaseOffset(Object[].class)} */
1178 public static final int ARRAY_OBJECT_BASE_OFFSET
1179 = theUnsafe.arrayBaseOffset(Object[].class);
1180
1181 /**
1182 * Reports the scale factor for addressing elements in the storage
1183 * allocation of a given array class. However, arrays of "narrow" types
1184 * will generally not work properly with accessors like {@link
1185 * #getByte(Object, long)}, so the scale factor for such classes is reported
1186 * as zero.
1187 *
1188 * @see #arrayBaseOffset
1189 * @see #getInt(Object, long)
1190 * @see #putInt(Object, long, int)
1191 */
1192 public int arrayIndexScale(Class<?> arrayClass) {
1193 if (arrayClass == null) {
1194 throw new NullPointerException();
1195 }
1196
1197 return arrayIndexScale0(arrayClass);
1198 }
1199
1200
1201 /** The value of {@code arrayIndexScale(boolean[].class)} */
1202 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1203 = theUnsafe.arrayIndexScale(boolean[].class);
1204
1205 /** The value of {@code arrayIndexScale(byte[].class)} */
1206 public static final int ARRAY_BYTE_INDEX_SCALE
1207 = theUnsafe.arrayIndexScale(byte[].class);
1208
1209 /** The value of {@code arrayIndexScale(short[].class)} */
1210 public static final int ARRAY_SHORT_INDEX_SCALE
1211 = theUnsafe.arrayIndexScale(short[].class);
1212
1213 /** The value of {@code arrayIndexScale(char[].class)} */
1214 public static final int ARRAY_CHAR_INDEX_SCALE
1215 = theUnsafe.arrayIndexScale(char[].class);
1216
1217 /** The value of {@code arrayIndexScale(int[].class)} */
1218 public static final int ARRAY_INT_INDEX_SCALE
1219 = theUnsafe.arrayIndexScale(int[].class);
1220
1221 /** The value of {@code arrayIndexScale(long[].class)} */
1222 public static final int ARRAY_LONG_INDEX_SCALE
1223 = theUnsafe.arrayIndexScale(long[].class);
1224
1225 /** The value of {@code arrayIndexScale(float[].class)} */
1226 public static final int ARRAY_FLOAT_INDEX_SCALE
1227 = theUnsafe.arrayIndexScale(float[].class);
1228
1229 /** The value of {@code arrayIndexScale(double[].class)} */
1230 public static final int ARRAY_DOUBLE_INDEX_SCALE
1231 = theUnsafe.arrayIndexScale(double[].class);
1232
1233 /** The value of {@code arrayIndexScale(Object[].class)} */
1234 public static final int ARRAY_OBJECT_INDEX_SCALE
1235 = theUnsafe.arrayIndexScale(Object[].class);
1236
1237 /**
1238 * Reports the size in bytes of a native pointer, as stored via {@link
1239 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1240 * other primitive types (as stored in native memory blocks) is determined
1241 * fully by their information content.
1242 */
1243 public int addressSize() {
1244 return ADDRESS_SIZE;
1245 }
1246
1247 /** The value of {@code addressSize()} */
1248 public static final int ADDRESS_SIZE = theUnsafe.addressSize0();
1249
1250 /**
1251 * Reports the size in bytes of a native memory page (whatever that is).
1252 * This value will always be a power of two.
1253 */
1254 public native int pageSize();
1255
1256 /// random trusted operations from JNI:
1257
1258 /**
1259 * Tells the VM to define a class, without security checks. By default, the
1260 * class loader and protection domain come from the caller's class.
1261 */
1262 public Class<?> defineClass(String name, byte[] b, int off, int len,
1263 ClassLoader loader,
1264 ProtectionDomain protectionDomain) {
1265 if (b == null) {
1266 throw new NullPointerException();
1267 }
1268 if (len < 0) {
1269 throw new ArrayIndexOutOfBoundsException();
1270 }
1271
1272 return defineClass0(name, b, off, len, loader, protectionDomain);
1273 }
1274
1275 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1276 ClassLoader loader,
1277 ProtectionDomain protectionDomain);
1278
1279 /**
1280 * Defines a class but does not make it known to the class loader or system dictionary.
1281 * <p>
1282 * For each CP entry, the corresponding CP patch must either be null or have
1283 * the a format that matches its tag:
1284 * <ul>
1285 * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
1286 * <li>Utf8: a string (must have suitable syntax if used as signature or name)
1287 * <li>Class: any java.lang.Class object
1288 * <li>String: any object (not just a java.lang.String)
1289 * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
1290 * </ul>
1291 * @param hostClass context for linkage, access control, protection domain, and class loader
1292 * @param data bytes of a class file
1293 * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
1294 */
1295 public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {
1296 if (hostClass == null || data == null) {
1297 throw new NullPointerException();
1298 }
1299 if (hostClass.isArray() || hostClass.isPrimitive()) {
1300 throw new IllegalArgumentException();
1301 }
1302
1303 return defineAnonymousClass0(hostClass, data, cpPatches);
1304 }
1305
1306 /**
1307 * Allocates an instance but does not run any constructor.
1308 * Initializes the class if it has not yet been.
1309 */
1310 @HotSpotIntrinsicCandidate
1311 public native Object allocateInstance(Class<?> cls)
1312 throws InstantiationException;
1313
1314 /**
1315 * Allocates an array of a given type, but does not do zeroing.
1316 * <p>
1317 * This method should only be used in the very rare cases where a high-performance code
1318 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1319 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1320 * <p>
1321 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1322 * before allowing untrusted code, or code in other threads, to observe the reference
1323 * to the newly allocated array. In addition, the publication of the array reference must be
1324 * safe according to the Java Memory Model requirements.
1325 * <p>
1326 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1327 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1328 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1329 * or issuing a {@link #storeFence} before publishing the reference.
1330 * <p>
1331 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1332 * elements that could break heap integrity.
1333 *
1334 * @param componentType array component type to allocate
1335 * @param length array size to allocate
1336 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1337 * or the length is negative
1338 */
1339 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1340 if (componentType == null) {
1341 throw new IllegalArgumentException("Component type is null");
1342 }
1343 if (!componentType.isPrimitive()) {
1344 throw new IllegalArgumentException("Component type is not primitive");
1345 }
1346 if (length < 0) {
1347 throw new IllegalArgumentException("Negative length");
1348 }
1349 return allocateUninitializedArray0(componentType, length);
1350 }
1351
1352 @HotSpotIntrinsicCandidate
1353 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1354 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1355 // return the zeroed arrays.
1356 if (componentType == byte.class) return new byte[length];
1357 if (componentType == boolean.class) return new boolean[length];
1358 if (componentType == short.class) return new short[length];
1359 if (componentType == char.class) return new char[length];
1360 if (componentType == int.class) return new int[length];
1361 if (componentType == float.class) return new float[length];
1362 if (componentType == long.class) return new long[length];
1363 if (componentType == double.class) return new double[length];
1364 return null;
1365 }
1366
1367 /** Throws the exception without telling the verifier. */
1368 public native void throwException(Throwable ee);
1369
1370 /**
1371 * Atomically updates Java variable to {@code x} if it is currently
1372 * holding {@code expected}.
1373 *
1374 * <p>This operation has memory semantics of a {@code volatile} read
1375 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1376 *
1377 * @return {@code true} if successful
1378 */
1379 @HotSpotIntrinsicCandidate
1380 public final native boolean compareAndSetObject(Object o, long offset,
1381 Object expected,
1382 Object x);
1383
1384 @HotSpotIntrinsicCandidate
1385 public final native Object compareAndExchangeObject(Object o, long offset,
1386 Object expected,
1387 Object x);
1388
1389 @HotSpotIntrinsicCandidate
1390 public final Object compareAndExchangeObjectAcquire(Object o, long offset,
1391 Object expected,
1392 Object x) {
1393 return compareAndExchangeObject(o, offset, expected, x);
1394 }
1395
1396 @HotSpotIntrinsicCandidate
1397 public final Object compareAndExchangeObjectRelease(Object o, long offset,
1398 Object expected,
1399 Object x) {
1400 return compareAndExchangeObject(o, offset, expected, x);
1401 }
1402
1403 @HotSpotIntrinsicCandidate
1404 public final boolean weakCompareAndSetObjectPlain(Object o, long offset,
1405 Object expected,
1406 Object x) {
1407 return compareAndSetObject(o, offset, expected, x);
1408 }
1409
1410 @HotSpotIntrinsicCandidate
1411 public final boolean weakCompareAndSetObjectAcquire(Object o, long offset,
1412 Object expected,
1413 Object x) {
1414 return compareAndSetObject(o, offset, expected, x);
1415 }
1416
1417 @HotSpotIntrinsicCandidate
1418 public final boolean weakCompareAndSetObjectRelease(Object o, long offset,
1419 Object expected,
1420 Object x) {
1421 return compareAndSetObject(o, offset, expected, x);
1422 }
1423
1424 @HotSpotIntrinsicCandidate
1425 public final boolean weakCompareAndSetObject(Object o, long offset,
1426 Object expected,
1427 Object x) {
1428 return compareAndSetObject(o, offset, expected, x);
1429 }
1430
1431 /**
1432 * Atomically updates Java variable to {@code x} if it is currently
1433 * holding {@code expected}.
1434 *
1435 * <p>This operation has memory semantics of a {@code volatile} read
1436 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1437 *
1438 * @return {@code true} if successful
1439 */
1440 @HotSpotIntrinsicCandidate
1441 public final native boolean compareAndSetInt(Object o, long offset,
1442 int expected,
1443 int x);
1444
1445 @HotSpotIntrinsicCandidate
1446 public final native int compareAndExchangeInt(Object o, long offset,
1447 int expected,
1448 int x);
1449
1450 @HotSpotIntrinsicCandidate
1451 public final int compareAndExchangeIntAcquire(Object o, long offset,
1452 int expected,
1453 int x) {
1454 return compareAndExchangeInt(o, offset, expected, x);
1455 }
1456
1457 @HotSpotIntrinsicCandidate
1458 public final int compareAndExchangeIntRelease(Object o, long offset,
1459 int expected,
1460 int x) {
1461 return compareAndExchangeInt(o, offset, expected, x);
1462 }
1463
1464 @HotSpotIntrinsicCandidate
1465 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1466 int expected,
1467 int x) {
1468 return compareAndSetInt(o, offset, expected, x);
1469 }
1470
1471 @HotSpotIntrinsicCandidate
1472 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1473 int expected,
1474 int x) {
1475 return compareAndSetInt(o, offset, expected, x);
1476 }
1477
1478 @HotSpotIntrinsicCandidate
1479 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1480 int expected,
1481 int x) {
1482 return compareAndSetInt(o, offset, expected, x);
1483 }
1484
1485 @HotSpotIntrinsicCandidate
1486 public final boolean weakCompareAndSetInt(Object o, long offset,
1487 int expected,
1488 int x) {
1489 return compareAndSetInt(o, offset, expected, x);
1490 }
1491
1492 @HotSpotIntrinsicCandidate
1493 public final byte compareAndExchangeByte(Object o, long offset,
1494 byte expected,
1495 byte x) {
1496 long wordOffset = offset & ~3;
1497 int shift = (int) (offset & 3) << 3;
1498 if (BE) {
1499 shift = 24 - shift;
1500 }
1501 int mask = 0xFF << shift;
1502 int maskedExpected = (expected & 0xFF) << shift;
1503 int maskedX = (x & 0xFF) << shift;
1504 int fullWord;
1505 do {
1506 fullWord = getIntVolatile(o, wordOffset);
1507 if ((fullWord & mask) != maskedExpected)
1508 return (byte) ((fullWord & mask) >> shift);
1509 } while (!weakCompareAndSetInt(o, wordOffset,
1510 fullWord, (fullWord & ~mask) | maskedX));
1511 return expected;
1512 }
1513
1514 @HotSpotIntrinsicCandidate
1515 public final boolean compareAndSetByte(Object o, long offset,
1516 byte expected,
1517 byte x) {
1518 return compareAndExchangeByte(o, offset, expected, x) == expected;
1519 }
1520
1521 @HotSpotIntrinsicCandidate
1522 public final boolean weakCompareAndSetByte(Object o, long offset,
1523 byte expected,
1524 byte x) {
1525 return compareAndSetByte(o, offset, expected, x);
1526 }
1527
1528 @HotSpotIntrinsicCandidate
1529 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1530 byte expected,
1531 byte x) {
1532 return weakCompareAndSetByte(o, offset, expected, x);
1533 }
1534
1535 @HotSpotIntrinsicCandidate
1536 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1537 byte expected,
1538 byte x) {
1539 return weakCompareAndSetByte(o, offset, expected, x);
1540 }
1541
1542 @HotSpotIntrinsicCandidate
1543 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1544 byte expected,
1545 byte x) {
1546 return weakCompareAndSetByte(o, offset, expected, x);
1547 }
1548
1549 @HotSpotIntrinsicCandidate
1550 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1551 byte expected,
1552 byte x) {
1553 return compareAndExchangeByte(o, offset, expected, x);
1554 }
1555
1556 @HotSpotIntrinsicCandidate
1557 public final byte compareAndExchangeByteRelease(Object o, long offset,
1558 byte expected,
1559 byte x) {
1560 return compareAndExchangeByte(o, offset, expected, x);
1561 }
1562
1563 @HotSpotIntrinsicCandidate
1564 public final short compareAndExchangeShort(Object o, long offset,
1565 short expected,
1566 short x) {
1567 if ((offset & 3) == 3) {
1568 throw new IllegalArgumentException("Update spans the word, not supported");
1569 }
1570 long wordOffset = offset & ~3;
1571 int shift = (int) (offset & 3) << 3;
1572 if (BE) {
1573 shift = 16 - shift;
1574 }
1575 int mask = 0xFFFF << shift;
1576 int maskedExpected = (expected & 0xFFFF) << shift;
1577 int maskedX = (x & 0xFFFF) << shift;
1578 int fullWord;
1579 do {
1580 fullWord = getIntVolatile(o, wordOffset);
1581 if ((fullWord & mask) != maskedExpected) {
1582 return (short) ((fullWord & mask) >> shift);
1583 }
1584 } while (!weakCompareAndSetInt(o, wordOffset,
1585 fullWord, (fullWord & ~mask) | maskedX));
1586 return expected;
1587 }
1588
1589 @HotSpotIntrinsicCandidate
1590 public final boolean compareAndSetShort(Object o, long offset,
1591 short expected,
1592 short x) {
1593 return compareAndExchangeShort(o, offset, expected, x) == expected;
1594 }
1595
1596 @HotSpotIntrinsicCandidate
1597 public final boolean weakCompareAndSetShort(Object o, long offset,
1598 short expected,
1599 short x) {
1600 return compareAndSetShort(o, offset, expected, x);
1601 }
1602
1603 @HotSpotIntrinsicCandidate
1604 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1605 short expected,
1606 short x) {
1607 return weakCompareAndSetShort(o, offset, expected, x);
1608 }
1609
1610 @HotSpotIntrinsicCandidate
1611 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1612 short expected,
1613 short x) {
1614 return weakCompareAndSetShort(o, offset, expected, x);
1615 }
1616
1617 @HotSpotIntrinsicCandidate
1618 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1619 short expected,
1620 short x) {
1621 return weakCompareAndSetShort(o, offset, expected, x);
1622 }
1623
1624
1625 @HotSpotIntrinsicCandidate
1626 public final short compareAndExchangeShortAcquire(Object o, long offset,
1627 short expected,
1628 short x) {
1629 return compareAndExchangeShort(o, offset, expected, x);
1630 }
1631
1632 @HotSpotIntrinsicCandidate
1633 public final short compareAndExchangeShortRelease(Object o, long offset,
1634 short expected,
1635 short x) {
1636 return compareAndExchangeShort(o, offset, expected, x);
1637 }
1638
1639 @ForceInline
1640 private char s2c(short s) {
1641 return (char) s;
1642 }
1643
1644 @ForceInline
1645 private short c2s(char s) {
1646 return (short) s;
1647 }
1648
1649 @ForceInline
1650 public final boolean compareAndSetChar(Object o, long offset,
1651 char expected,
1652 char x) {
1653 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1654 }
1655
1656 @ForceInline
1657 public final char compareAndExchangeChar(Object o, long offset,
1658 char expected,
1659 char x) {
1660 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1661 }
1662
1663 @ForceInline
1664 public final char compareAndExchangeCharAcquire(Object o, long offset,
1665 char expected,
1666 char x) {
1667 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1668 }
1669
1670 @ForceInline
1671 public final char compareAndExchangeCharRelease(Object o, long offset,
1672 char expected,
1673 char x) {
1674 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1675 }
1676
1677 @ForceInline
1678 public final boolean weakCompareAndSetChar(Object o, long offset,
1679 char expected,
1680 char x) {
1681 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1682 }
1683
1684 @ForceInline
1685 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1686 char expected,
1687 char x) {
1688 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1689 }
1690
1691 @ForceInline
1692 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1693 char expected,
1694 char x) {
1695 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1696 }
1697
1698 @ForceInline
1699 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1700 char expected,
1701 char x) {
1702 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1703 }
1704
1705 /**
1706 * The JVM converts integral values to boolean values using two
1707 * different conventions, byte testing against zero and truncation
1708 * to least-significant bit.
1709 *
1710 * <p>The JNI documents specify that, at least for returning
1711 * values from native methods, a Java boolean value is converted
1712 * to the value-set 0..1 by first truncating to a byte (0..255 or
1713 * maybe -128..127) and then testing against zero. Thus, Java
1714 * booleans in non-Java data structures are by convention
1715 * represented as 8-bit containers containing either zero (for
1716 * false) or any non-zero value (for true).
1717 *
1718 * <p>Java booleans in the heap are also stored in bytes, but are
1719 * strongly normalized to the value-set 0..1 (i.e., they are
1720 * truncated to the least-significant bit).
1721 *
1722 * <p>The main reason for having different conventions for
1723 * conversion is performance: Truncation to the least-significant
1724 * bit can be usually implemented with fewer (machine)
1725 * instructions than byte testing against zero.
1726 *
1727 * <p>A number of Unsafe methods load boolean values from the heap
1728 * as bytes. Unsafe converts those values according to the JNI
1729 * rules (i.e, using the "testing against zero" convention). The
1730 * method {@code byte2bool} implements that conversion.
1731 *
1732 * @param b the byte to be converted to boolean
1733 * @return the result of the conversion
1734 */
1735 @ForceInline
1736 private boolean byte2bool(byte b) {
1737 return b != 0;
1738 }
1739
1740 /**
1741 * Convert a boolean value to a byte. The return value is strongly
1742 * normalized to the value-set 0..1 (i.e., the value is truncated
1743 * to the least-significant bit). See {@link #byte2bool(byte)} for
1744 * more details on conversion conventions.
1745 *
1746 * @param b the boolean to be converted to byte (and then normalized)
1747 * @return the result of the conversion
1748 */
1749 @ForceInline
1750 private byte bool2byte(boolean b) {
1751 return b ? (byte)1 : (byte)0;
1752 }
1753
1754 @ForceInline
1755 public final boolean compareAndSetBoolean(Object o, long offset,
1756 boolean expected,
1757 boolean x) {
1758 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1759 }
1760
1761 @ForceInline
1762 public final boolean compareAndExchangeBoolean(Object o, long offset,
1763 boolean expected,
1764 boolean x) {
1765 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1766 }
1767
1768 @ForceInline
1769 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1770 boolean expected,
1771 boolean x) {
1772 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1773 }
1774
1775 @ForceInline
1776 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1777 boolean expected,
1778 boolean x) {
1779 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1780 }
1781
1782 @ForceInline
1783 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1784 boolean expected,
1785 boolean x) {
1786 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1787 }
1788
1789 @ForceInline
1790 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1791 boolean expected,
1792 boolean x) {
1793 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1794 }
1795
1796 @ForceInline
1797 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1798 boolean expected,
1799 boolean x) {
1800 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1801 }
1802
1803 @ForceInline
1804 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1805 boolean expected,
1806 boolean x) {
1807 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1808 }
1809
1810 /**
1811 * Atomically updates Java variable to {@code x} if it is currently
1812 * holding {@code expected}.
1813 *
1814 * <p>This operation has memory semantics of a {@code volatile} read
1815 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1816 *
1817 * @return {@code true} if successful
1818 */
1819 @ForceInline
1820 public final boolean compareAndSetFloat(Object o, long offset,
1821 float expected,
1822 float x) {
1823 return compareAndSetInt(o, offset,
1824 Float.floatToRawIntBits(expected),
1825 Float.floatToRawIntBits(x));
1826 }
1827
1828 @ForceInline
1829 public final float compareAndExchangeFloat(Object o, long offset,
1830 float expected,
1831 float x) {
1832 int w = compareAndExchangeInt(o, offset,
1833 Float.floatToRawIntBits(expected),
1834 Float.floatToRawIntBits(x));
1835 return Float.intBitsToFloat(w);
1836 }
1837
1838 @ForceInline
1839 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1840 float expected,
1841 float x) {
1842 int w = compareAndExchangeIntAcquire(o, offset,
1843 Float.floatToRawIntBits(expected),
1844 Float.floatToRawIntBits(x));
1845 return Float.intBitsToFloat(w);
1846 }
1847
1848 @ForceInline
1849 public final float compareAndExchangeFloatRelease(Object o, long offset,
1850 float expected,
1851 float x) {
1852 int w = compareAndExchangeIntRelease(o, offset,
1853 Float.floatToRawIntBits(expected),
1854 Float.floatToRawIntBits(x));
1855 return Float.intBitsToFloat(w);
1856 }
1857
1858 @ForceInline
1859 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
1860 float expected,
1861 float x) {
1862 return weakCompareAndSetIntPlain(o, offset,
1863 Float.floatToRawIntBits(expected),
1864 Float.floatToRawIntBits(x));
1865 }
1866
1867 @ForceInline
1868 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
1869 float expected,
1870 float x) {
1871 return weakCompareAndSetIntAcquire(o, offset,
1872 Float.floatToRawIntBits(expected),
1873 Float.floatToRawIntBits(x));
1874 }
1875
1876 @ForceInline
1877 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
1878 float expected,
1879 float x) {
1880 return weakCompareAndSetIntRelease(o, offset,
1881 Float.floatToRawIntBits(expected),
1882 Float.floatToRawIntBits(x));
1883 }
1884
1885 @ForceInline
1886 public final boolean weakCompareAndSetFloat(Object o, long offset,
1887 float expected,
1888 float x) {
1889 return weakCompareAndSetInt(o, offset,
1890 Float.floatToRawIntBits(expected),
1891 Float.floatToRawIntBits(x));
1892 }
1893
1894 /**
1895 * Atomically updates Java variable to {@code x} if it is currently
1896 * holding {@code expected}.
1897 *
1898 * <p>This operation has memory semantics of a {@code volatile} read
1899 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1900 *
1901 * @return {@code true} if successful
1902 */
1903 @ForceInline
1904 public final boolean compareAndSetDouble(Object o, long offset,
1905 double expected,
1906 double x) {
1907 return compareAndSetLong(o, offset,
1908 Double.doubleToRawLongBits(expected),
1909 Double.doubleToRawLongBits(x));
1910 }
1911
1912 @ForceInline
1913 public final double compareAndExchangeDouble(Object o, long offset,
1914 double expected,
1915 double x) {
1916 long w = compareAndExchangeLong(o, offset,
1917 Double.doubleToRawLongBits(expected),
1918 Double.doubleToRawLongBits(x));
1919 return Double.longBitsToDouble(w);
1920 }
1921
1922 @ForceInline
1923 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
1924 double expected,
1925 double x) {
1926 long w = compareAndExchangeLongAcquire(o, offset,
1927 Double.doubleToRawLongBits(expected),
1928 Double.doubleToRawLongBits(x));
1929 return Double.longBitsToDouble(w);
1930 }
1931
1932 @ForceInline
1933 public final double compareAndExchangeDoubleRelease(Object o, long offset,
1934 double expected,
1935 double x) {
1936 long w = compareAndExchangeLongRelease(o, offset,
1937 Double.doubleToRawLongBits(expected),
1938 Double.doubleToRawLongBits(x));
1939 return Double.longBitsToDouble(w);
1940 }
1941
1942 @ForceInline
1943 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
1944 double expected,
1945 double x) {
1946 return weakCompareAndSetLongPlain(o, offset,
1947 Double.doubleToRawLongBits(expected),
1948 Double.doubleToRawLongBits(x));
1949 }
1950
1951 @ForceInline
1952 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
1953 double expected,
1954 double x) {
1955 return weakCompareAndSetLongAcquire(o, offset,
1956 Double.doubleToRawLongBits(expected),
1957 Double.doubleToRawLongBits(x));
1958 }
1959
1960 @ForceInline
1961 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
1962 double expected,
1963 double x) {
1964 return weakCompareAndSetLongRelease(o, offset,
1965 Double.doubleToRawLongBits(expected),
1966 Double.doubleToRawLongBits(x));
1967 }
1968
1969 @ForceInline
1970 public final boolean weakCompareAndSetDouble(Object o, long offset,
1971 double expected,
1972 double x) {
1973 return weakCompareAndSetLong(o, offset,
1974 Double.doubleToRawLongBits(expected),
1975 Double.doubleToRawLongBits(x));
1976 }
1977
1978 /**
1979 * Atomically updates Java variable to {@code x} if it is currently
1980 * holding {@code expected}.
1981 *
1982 * <p>This operation has memory semantics of a {@code volatile} read
1983 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1984 *
1985 * @return {@code true} if successful
1986 */
1987 @HotSpotIntrinsicCandidate
1988 public final native boolean compareAndSetLong(Object o, long offset,
1989 long expected,
1990 long x);
1991
1992 @HotSpotIntrinsicCandidate
1993 public final native long compareAndExchangeLong(Object o, long offset,
1994 long expected,
1995 long x);
1996
1997 @HotSpotIntrinsicCandidate
1998 public final long compareAndExchangeLongAcquire(Object o, long offset,
1999 long expected,
2000 long x) {
2001 return compareAndExchangeLong(o, offset, expected, x);
2002 }
2003
2004 @HotSpotIntrinsicCandidate
2005 public final long compareAndExchangeLongRelease(Object o, long offset,
2006 long expected,
2007 long x) {
2008 return compareAndExchangeLong(o, offset, expected, x);
2009 }
2010
2011 @HotSpotIntrinsicCandidate
2012 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2013 long expected,
2014 long x) {
2015 return compareAndSetLong(o, offset, expected, x);
2016 }
2017
2018 @HotSpotIntrinsicCandidate
2019 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2020 long expected,
2021 long x) {
2022 return compareAndSetLong(o, offset, expected, x);
2023 }
2024
2025 @HotSpotIntrinsicCandidate
2026 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2027 long expected,
2028 long x) {
2029 return compareAndSetLong(o, offset, expected, x);
2030 }
2031
2032 @HotSpotIntrinsicCandidate
2033 public final boolean weakCompareAndSetLong(Object o, long offset,
2034 long expected,
2035 long x) {
2036 return compareAndSetLong(o, offset, expected, x);
2037 }
2038
2039 /**
2040 * Fetches a reference value from a given Java variable, with volatile
2041 * load semantics. Otherwise identical to {@link #getObject(Object, long)}
2042 */
2043 @HotSpotIntrinsicCandidate
2044 public native Object getObjectVolatile(Object o, long offset);
2045
2046 /**
2047 * Stores a reference value into a given Java variable, with
2048 * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
2049 */
2050 @HotSpotIntrinsicCandidate
2051 public native void putObjectVolatile(Object o, long offset, Object x);
2052
2053 /** Volatile version of {@link #getInt(Object, long)} */
2054 @HotSpotIntrinsicCandidate
2055 public native int getIntVolatile(Object o, long offset);
2056
2057 /** Volatile version of {@link #putInt(Object, long, int)} */
2058 @HotSpotIntrinsicCandidate
2059 public native void putIntVolatile(Object o, long offset, int x);
2060
2061 /** Volatile version of {@link #getBoolean(Object, long)} */
2062 @HotSpotIntrinsicCandidate
2063 public native boolean getBooleanVolatile(Object o, long offset);
2064
2065 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2066 @HotSpotIntrinsicCandidate
2067 public native void putBooleanVolatile(Object o, long offset, boolean x);
2068
2069 /** Volatile version of {@link #getByte(Object, long)} */
2070 @HotSpotIntrinsicCandidate
2071 public native byte getByteVolatile(Object o, long offset);
2072
2073 /** Volatile version of {@link #putByte(Object, long, byte)} */
2074 @HotSpotIntrinsicCandidate
2075 public native void putByteVolatile(Object o, long offset, byte x);
2076
2077 /** Volatile version of {@link #getShort(Object, long)} */
2078 @HotSpotIntrinsicCandidate
2079 public native short getShortVolatile(Object o, long offset);
2080
2081 /** Volatile version of {@link #putShort(Object, long, short)} */
2082 @HotSpotIntrinsicCandidate
2083 public native void putShortVolatile(Object o, long offset, short x);
2084
2085 /** Volatile version of {@link #getChar(Object, long)} */
2086 @HotSpotIntrinsicCandidate
2087 public native char getCharVolatile(Object o, long offset);
2088
2089 /** Volatile version of {@link #putChar(Object, long, char)} */
2090 @HotSpotIntrinsicCandidate
2091 public native void putCharVolatile(Object o, long offset, char x);
2092
2093 /** Volatile version of {@link #getLong(Object, long)} */
2094 @HotSpotIntrinsicCandidate
2095 public native long getLongVolatile(Object o, long offset);
2096
2097 /** Volatile version of {@link #putLong(Object, long, long)} */
2098 @HotSpotIntrinsicCandidate
2099 public native void putLongVolatile(Object o, long offset, long x);
2100
2101 /** Volatile version of {@link #getFloat(Object, long)} */
2102 @HotSpotIntrinsicCandidate
2103 public native float getFloatVolatile(Object o, long offset);
2104
2105 /** Volatile version of {@link #putFloat(Object, long, float)} */
2106 @HotSpotIntrinsicCandidate
2107 public native void putFloatVolatile(Object o, long offset, float x);
2108
2109 /** Volatile version of {@link #getDouble(Object, long)} */
2110 @HotSpotIntrinsicCandidate
2111 public native double getDoubleVolatile(Object o, long offset);
2112
2113 /** Volatile version of {@link #putDouble(Object, long, double)} */
2114 @HotSpotIntrinsicCandidate
2115 public native void putDoubleVolatile(Object o, long offset, double x);
2116
2117
2118
2119 /** Acquire version of {@link #getObjectVolatile(Object, long)} */
2120 @HotSpotIntrinsicCandidate
2121 public final Object getObjectAcquire(Object o, long offset) {
2122 return getObjectVolatile(o, offset);
2123 }
2124
2125 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2126 @HotSpotIntrinsicCandidate
2127 public final boolean getBooleanAcquire(Object o, long offset) {
2128 return getBooleanVolatile(o, offset);
2129 }
2130
2131 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2132 @HotSpotIntrinsicCandidate
2133 public final byte getByteAcquire(Object o, long offset) {
2134 return getByteVolatile(o, offset);
2135 }
2136
2137 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2138 @HotSpotIntrinsicCandidate
2139 public final short getShortAcquire(Object o, long offset) {
2140 return getShortVolatile(o, offset);
2141 }
2142
2143 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2144 @HotSpotIntrinsicCandidate
2145 public final char getCharAcquire(Object o, long offset) {
2146 return getCharVolatile(o, offset);
2147 }
2148
2149 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2150 @HotSpotIntrinsicCandidate
2151 public final int getIntAcquire(Object o, long offset) {
2152 return getIntVolatile(o, offset);
2153 }
2154
2155 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2156 @HotSpotIntrinsicCandidate
2157 public final float getFloatAcquire(Object o, long offset) {
2158 return getFloatVolatile(o, offset);
2159 }
2160
2161 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2162 @HotSpotIntrinsicCandidate
2163 public final long getLongAcquire(Object o, long offset) {
2164 return getLongVolatile(o, offset);
2165 }
2166
2167 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2168 @HotSpotIntrinsicCandidate
2169 public final double getDoubleAcquire(Object o, long offset) {
2170 return getDoubleVolatile(o, offset);
2171 }
2172
2173 /*
2174 * Versions of {@link #putObjectVolatile(Object, long, Object)}
2175 * that do not guarantee immediate visibility of the store to
2176 * other threads. This method is generally only useful if the
2177 * underlying field is a Java volatile (or if an array cell, one
2178 * that is otherwise only accessed using volatile accesses).
2179 *
2180 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2181 */
2182
2183 /** Release version of {@link #putObjectVolatile(Object, long, Object)} */
2184 @HotSpotIntrinsicCandidate
2185 public final void putObjectRelease(Object o, long offset, Object x) {
2186 putObjectVolatile(o, offset, x);
2187 }
2188
2189 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2190 @HotSpotIntrinsicCandidate
2191 public final void putBooleanRelease(Object o, long offset, boolean x) {
2192 putBooleanVolatile(o, offset, x);
2193 }
2194
2195 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2196 @HotSpotIntrinsicCandidate
2197 public final void putByteRelease(Object o, long offset, byte x) {
2198 putByteVolatile(o, offset, x);
2199 }
2200
2201 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2202 @HotSpotIntrinsicCandidate
2203 public final void putShortRelease(Object o, long offset, short x) {
2204 putShortVolatile(o, offset, x);
2205 }
2206
2207 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2208 @HotSpotIntrinsicCandidate
2209 public final void putCharRelease(Object o, long offset, char x) {
2210 putCharVolatile(o, offset, x);
2211 }
2212
2213 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2214 @HotSpotIntrinsicCandidate
2215 public final void putIntRelease(Object o, long offset, int x) {
2216 putIntVolatile(o, offset, x);
2217 }
2218
2219 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2220 @HotSpotIntrinsicCandidate
2221 public final void putFloatRelease(Object o, long offset, float x) {
2222 putFloatVolatile(o, offset, x);
2223 }
2224
2225 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2226 @HotSpotIntrinsicCandidate
2227 public final void putLongRelease(Object o, long offset, long x) {
2228 putLongVolatile(o, offset, x);
2229 }
2230
2231 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2232 @HotSpotIntrinsicCandidate
2233 public final void putDoubleRelease(Object o, long offset, double x) {
2234 putDoubleVolatile(o, offset, x);
2235 }
2236
2237 // ------------------------------ Opaque --------------------------------------
2238
2239 /** Opaque version of {@link #getObjectVolatile(Object, long)} */
2240 @HotSpotIntrinsicCandidate
2241 public final Object getObjectOpaque(Object o, long offset) {
2242 return getObjectVolatile(o, offset);
2243 }
2244
2245 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2246 @HotSpotIntrinsicCandidate
2247 public final boolean getBooleanOpaque(Object o, long offset) {
2248 return getBooleanVolatile(o, offset);
2249 }
2250
2251 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2252 @HotSpotIntrinsicCandidate
2253 public final byte getByteOpaque(Object o, long offset) {
2254 return getByteVolatile(o, offset);
2255 }
2256
2257 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2258 @HotSpotIntrinsicCandidate
2259 public final short getShortOpaque(Object o, long offset) {
2260 return getShortVolatile(o, offset);
2261 }
2262
2263 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2264 @HotSpotIntrinsicCandidate
2265 public final char getCharOpaque(Object o, long offset) {
2266 return getCharVolatile(o, offset);
2267 }
2268
2269 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2270 @HotSpotIntrinsicCandidate
2271 public final int getIntOpaque(Object o, long offset) {
2272 return getIntVolatile(o, offset);
2273 }
2274
2275 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2276 @HotSpotIntrinsicCandidate
2277 public final float getFloatOpaque(Object o, long offset) {
2278 return getFloatVolatile(o, offset);
2279 }
2280
2281 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2282 @HotSpotIntrinsicCandidate
2283 public final long getLongOpaque(Object o, long offset) {
2284 return getLongVolatile(o, offset);
2285 }
2286
2287 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2288 @HotSpotIntrinsicCandidate
2289 public final double getDoubleOpaque(Object o, long offset) {
2290 return getDoubleVolatile(o, offset);
2291 }
2292
2293 /** Opaque version of {@link #putObjectVolatile(Object, long, Object)} */
2294 @HotSpotIntrinsicCandidate
2295 public final void putObjectOpaque(Object o, long offset, Object x) {
2296 putObjectVolatile(o, offset, x);
2297 }
2298
2299 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2300 @HotSpotIntrinsicCandidate
2301 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2302 putBooleanVolatile(o, offset, x);
2303 }
2304
2305 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2306 @HotSpotIntrinsicCandidate
2307 public final void putByteOpaque(Object o, long offset, byte x) {
2308 putByteVolatile(o, offset, x);
2309 }
2310
2311 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2312 @HotSpotIntrinsicCandidate
2313 public final void putShortOpaque(Object o, long offset, short x) {
2314 putShortVolatile(o, offset, x);
2315 }
2316
2317 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2318 @HotSpotIntrinsicCandidate
2319 public final void putCharOpaque(Object o, long offset, char x) {
2320 putCharVolatile(o, offset, x);
2321 }
2322
2323 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2324 @HotSpotIntrinsicCandidate
2325 public final void putIntOpaque(Object o, long offset, int x) {
2326 putIntVolatile(o, offset, x);
2327 }
2328
2329 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2330 @HotSpotIntrinsicCandidate
2331 public final void putFloatOpaque(Object o, long offset, float x) {
2332 putFloatVolatile(o, offset, x);
2333 }
2334
2335 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2336 @HotSpotIntrinsicCandidate
2337 public final void putLongOpaque(Object o, long offset, long x) {
2338 putLongVolatile(o, offset, x);
2339 }
2340
2341 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2342 @HotSpotIntrinsicCandidate
2343 public final void putDoubleOpaque(Object o, long offset, double x) {
2344 putDoubleVolatile(o, offset, x);
2345 }
2346
2347 /**
2348 * Unblocks the given thread blocked on {@code park}, or, if it is
2349 * not blocked, causes the subsequent call to {@code park} not to
2350 * block. Note: this operation is "unsafe" solely because the
2351 * caller must somehow ensure that the thread has not been
2352 * destroyed. Nothing special is usually required to ensure this
2353 * when called from Java (in which there will ordinarily be a live
2354 * reference to the thread) but this is not nearly-automatically
2355 * so when calling from native code.
2356 *
2357 * @param thread the thread to unpark.
2358 */
2359 @HotSpotIntrinsicCandidate
2360 public native void unpark(Object thread);
2361
2362 /**
2363 * Blocks current thread, returning when a balancing
2364 * {@code unpark} occurs, or a balancing {@code unpark} has
2365 * already occurred, or the thread is interrupted, or, if not
2366 * absolute and time is not zero, the given time nanoseconds have
2367 * elapsed, or if absolute, the given deadline in milliseconds
2368 * since Epoch has passed, or spuriously (i.e., returning for no
2369 * "reason"). Note: This operation is in the Unsafe class only
2370 * because {@code unpark} is, so it would be strange to place it
2371 * elsewhere.
2372 */
2373 @HotSpotIntrinsicCandidate
2374 public native void park(boolean isAbsolute, long time);
2375
2376 /**
2377 * Gets the load average in the system run queue assigned
2378 * to the available processors averaged over various periods of time.
2379 * This method retrieves the given {@code nelem} samples and
2380 * assigns to the elements of the given {@code loadavg} array.
2381 * The system imposes a maximum of 3 samples, representing
2382 * averages over the last 1, 5, and 15 minutes, respectively.
2383 *
2384 * @param loadavg an array of double of size nelems
2385 * @param nelems the number of samples to be retrieved and
2386 * must be 1 to 3.
2387 *
2388 * @return the number of samples actually retrieved; or -1
2389 * if the load average is unobtainable.
2390 */
2391 public int getLoadAverage(double[] loadavg, int nelems) {
2392 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2393 throw new ArrayIndexOutOfBoundsException();
2394 }
2395
2396 return getLoadAverage0(loadavg, nelems);
2397 }
2398
2399 // The following contain CAS-based Java implementations used on
2400 // platforms not supporting native instructions
2401
2402 /**
2403 * Atomically adds the given value to the current value of a field
2404 * or array element within the given object {@code o}
2405 * at the given {@code offset}.
2406 *
2407 * @param o object/array to update the field/element in
2408 * @param offset field/element offset
2409 * @param delta the value to add
2410 * @return the previous value
2411 * @since 1.8
2412 */
2413 @HotSpotIntrinsicCandidate
2414 public final int getAndAddInt(Object o, long offset, int delta) {
2415 int v;
2416 do {
2417 v = getIntVolatile(o, offset);
2418 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2419 return v;
2420 }
2421
2422 @ForceInline
2423 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2424 int v;
2425 do {
2426 v = getInt(o, offset);
2427 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2428 return v;
2429 }
2430
2431 @ForceInline
2432 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2433 int v;
2434 do {
2435 v = getIntAcquire(o, offset);
2436 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2437 return v;
2438 }
2439
2440 /**
2441 * Atomically adds the given value to the current value of a field
2442 * or array element within the given object {@code o}
2443 * at the given {@code offset}.
2444 *
2445 * @param o object/array to update the field/element in
2446 * @param offset field/element offset
2447 * @param delta the value to add
2448 * @return the previous value
2449 * @since 1.8
2450 */
2451 @HotSpotIntrinsicCandidate
2452 public final long getAndAddLong(Object o, long offset, long delta) {
2453 long v;
2454 do {
2455 v = getLongVolatile(o, offset);
2456 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2457 return v;
2458 }
2459
2460 @ForceInline
2461 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2462 long v;
2463 do {
2464 v = getLong(o, offset);
2465 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2466 return v;
2467 }
2468
2469 @ForceInline
2470 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2471 long v;
2472 do {
2473 v = getLongAcquire(o, offset);
2474 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2475 return v;
2476 }
2477
2478 @HotSpotIntrinsicCandidate
2479 public final byte getAndAddByte(Object o, long offset, byte delta) {
2480 byte v;
2481 do {
2482 v = getByteVolatile(o, offset);
2483 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2484 return v;
2485 }
2486
2487 @ForceInline
2488 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2489 byte v;
2490 do {
2491 v = getByte(o, offset);
2492 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2493 return v;
2494 }
2495
2496 @ForceInline
2497 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2498 byte v;
2499 do {
2500 v = getByteAcquire(o, offset);
2501 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2502 return v;
2503 }
2504
2505 @HotSpotIntrinsicCandidate
2506 public final short getAndAddShort(Object o, long offset, short delta) {
2507 short v;
2508 do {
2509 v = getShortVolatile(o, offset);
2510 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2511 return v;
2512 }
2513
2514 @ForceInline
2515 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2516 short v;
2517 do {
2518 v = getShort(o, offset);
2519 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2520 return v;
2521 }
2522
2523 @ForceInline
2524 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2525 short v;
2526 do {
2527 v = getShortAcquire(o, offset);
2528 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2529 return v;
2530 }
2531
2532 @ForceInline
2533 public final char getAndAddChar(Object o, long offset, char delta) {
2534 return (char) getAndAddShort(o, offset, (short) delta);
2535 }
2536
2537 @ForceInline
2538 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2539 return (char) getAndAddShortRelease(o, offset, (short) delta);
2540 }
2541
2542 @ForceInline
2543 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2544 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2545 }
2546
2547 @ForceInline
2548 public final float getAndAddFloat(Object o, long offset, float delta) {
2549 int expectedBits;
2550 float v;
2551 do {
2552 // Load and CAS with the raw bits to avoid issues with NaNs and
2553 // possible bit conversion from signaling NaNs to quiet NaNs that
2554 // may result in the loop not terminating.
2555 expectedBits = getIntVolatile(o, offset);
2556 v = Float.intBitsToFloat(expectedBits);
2557 } while (!weakCompareAndSetInt(o, offset,
2558 expectedBits, Float.floatToRawIntBits(v + delta)));
2559 return v;
2560 }
2561
2562 @ForceInline
2563 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2564 int expectedBits;
2565 float v;
2566 do {
2567 // Load and CAS with the raw bits to avoid issues with NaNs and
2568 // possible bit conversion from signaling NaNs to quiet NaNs that
2569 // may result in the loop not terminating.
2570 expectedBits = getInt(o, offset);
2571 v = Float.intBitsToFloat(expectedBits);
2572 } while (!weakCompareAndSetIntRelease(o, offset,
2573 expectedBits, Float.floatToRawIntBits(v + delta)));
2574 return v;
2575 }
2576
2577 @ForceInline
2578 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2579 int expectedBits;
2580 float v;
2581 do {
2582 // Load and CAS with the raw bits to avoid issues with NaNs and
2583 // possible bit conversion from signaling NaNs to quiet NaNs that
2584 // may result in the loop not terminating.
2585 expectedBits = getIntAcquire(o, offset);
2586 v = Float.intBitsToFloat(expectedBits);
2587 } while (!weakCompareAndSetIntAcquire(o, offset,
2588 expectedBits, Float.floatToRawIntBits(v + delta)));
2589 return v;
2590 }
2591
2592 @ForceInline
2593 public final double getAndAddDouble(Object o, long offset, double delta) {
2594 long expectedBits;
2595 double v;
2596 do {
2597 // Load and CAS with the raw bits to avoid issues with NaNs and
2598 // possible bit conversion from signaling NaNs to quiet NaNs that
2599 // may result in the loop not terminating.
2600 expectedBits = getLongVolatile(o, offset);
2601 v = Double.longBitsToDouble(expectedBits);
2602 } while (!weakCompareAndSetLong(o, offset,
2603 expectedBits, Double.doubleToRawLongBits(v + delta)));
2604 return v;
2605 }
2606
2607 @ForceInline
2608 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2609 long expectedBits;
2610 double v;
2611 do {
2612 // Load and CAS with the raw bits to avoid issues with NaNs and
2613 // possible bit conversion from signaling NaNs to quiet NaNs that
2614 // may result in the loop not terminating.
2615 expectedBits = getLong(o, offset);
2616 v = Double.longBitsToDouble(expectedBits);
2617 } while (!weakCompareAndSetLongRelease(o, offset,
2618 expectedBits, Double.doubleToRawLongBits(v + delta)));
2619 return v;
2620 }
2621
2622 @ForceInline
2623 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2624 long expectedBits;
2625 double v;
2626 do {
2627 // Load and CAS with the raw bits to avoid issues with NaNs and
2628 // possible bit conversion from signaling NaNs to quiet NaNs that
2629 // may result in the loop not terminating.
2630 expectedBits = getLongAcquire(o, offset);
2631 v = Double.longBitsToDouble(expectedBits);
2632 } while (!weakCompareAndSetLongAcquire(o, offset,
2633 expectedBits, Double.doubleToRawLongBits(v + delta)));
2634 return v;
2635 }
2636
2637 /**
2638 * Atomically exchanges the given value with the current value of
2639 * a field or array element within the given object {@code o}
2640 * at the given {@code offset}.
2641 *
2642 * @param o object/array to update the field/element in
2643 * @param offset field/element offset
2644 * @param newValue new value
2645 * @return the previous value
2646 * @since 1.8
2647 */
2648 @HotSpotIntrinsicCandidate
2649 public final int getAndSetInt(Object o, long offset, int newValue) {
2650 int v;
2651 do {
2652 v = getIntVolatile(o, offset);
2653 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2654 return v;
2655 }
2656
2657 @ForceInline
2658 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2659 int v;
2660 do {
2661 v = getInt(o, offset);
2662 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2663 return v;
2664 }
2665
2666 @ForceInline
2667 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2668 int v;
2669 do {
2670 v = getIntAcquire(o, offset);
2671 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2672 return v;
2673 }
2674
2675 /**
2676 * Atomically exchanges the given value with the current value of
2677 * a field or array element within the given object {@code o}
2678 * at the given {@code offset}.
2679 *
2680 * @param o object/array to update the field/element in
2681 * @param offset field/element offset
2682 * @param newValue new value
2683 * @return the previous value
2684 * @since 1.8
2685 */
2686 @HotSpotIntrinsicCandidate
2687 public final long getAndSetLong(Object o, long offset, long newValue) {
2688 long v;
2689 do {
2690 v = getLongVolatile(o, offset);
2691 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2692 return v;
2693 }
2694
2695 @ForceInline
2696 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2697 long v;
2698 do {
2699 v = getLong(o, offset);
2700 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2701 return v;
2702 }
2703
2704 @ForceInline
2705 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2706 long v;
2707 do {
2708 v = getLongAcquire(o, offset);
2709 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2710 return v;
2711 }
2712
2713 /**
2714 * Atomically exchanges the given reference value with the current
2715 * reference value of a field or array element within the given
2716 * object {@code o} at the given {@code offset}.
2717 *
2718 * @param o object/array to update the field/element in
2719 * @param offset field/element offset
2720 * @param newValue new value
2721 * @return the previous value
2722 * @since 1.8
2723 */
2724 @HotSpotIntrinsicCandidate
2725 public final Object getAndSetObject(Object o, long offset, Object newValue) {
2726 Object v;
2727 do {
2728 v = getObjectVolatile(o, offset);
2729 } while (!weakCompareAndSetObject(o, offset, v, newValue));
2730 return v;
2731 }
2732
2733 @ForceInline
2734 public final Object getAndSetObjectRelease(Object o, long offset, Object newValue) {
2735 Object v;
2736 do {
2737 v = getObject(o, offset);
2738 } while (!weakCompareAndSetObjectRelease(o, offset, v, newValue));
2739 return v;
2740 }
2741
2742 @ForceInline
2743 public final Object getAndSetObjectAcquire(Object o, long offset, Object newValue) {
2744 Object v;
2745 do {
2746 v = getObjectAcquire(o, offset);
2747 } while (!weakCompareAndSetObjectAcquire(o, offset, v, newValue));
2748 return v;
2749 }
2750
2751 @HotSpotIntrinsicCandidate
2752 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2753 byte v;
2754 do {
2755 v = getByteVolatile(o, offset);
2756 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2757 return v;
2758 }
2759
2760 @ForceInline
2761 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2762 byte v;
2763 do {
2764 v = getByte(o, offset);
2765 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2766 return v;
2767 }
2768
2769 @ForceInline
2770 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2771 byte v;
2772 do {
2773 v = getByteAcquire(o, offset);
2774 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2775 return v;
2776 }
2777
2778 @ForceInline
2779 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2780 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2781 }
2782
2783 @ForceInline
2784 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2785 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2786 }
2787
2788 @ForceInline
2789 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2790 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2791 }
2792
2793 @HotSpotIntrinsicCandidate
2794 public final short getAndSetShort(Object o, long offset, short newValue) {
2795 short v;
2796 do {
2797 v = getShortVolatile(o, offset);
2798 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2799 return v;
2800 }
2801
2802 @ForceInline
2803 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
2804 short v;
2805 do {
2806 v = getShort(o, offset);
2807 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
2808 return v;
2809 }
2810
2811 @ForceInline
2812 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
2813 short v;
2814 do {
2815 v = getShortAcquire(o, offset);
2816 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
2817 return v;
2818 }
2819
2820 @ForceInline
2821 public final char getAndSetChar(Object o, long offset, char newValue) {
2822 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2823 }
2824
2825 @ForceInline
2826 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
2827 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
2828 }
2829
2830 @ForceInline
2831 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
2832 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
2833 }
2834
2835 @ForceInline
2836 public final float getAndSetFloat(Object o, long offset, float newValue) {
2837 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
2838 return Float.intBitsToFloat(v);
2839 }
2840
2841 @ForceInline
2842 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
2843 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
2844 return Float.intBitsToFloat(v);
2845 }
2846
2847 @ForceInline
2848 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
2849 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
2850 return Float.intBitsToFloat(v);
2851 }
2852
2853 @ForceInline
2854 public final double getAndSetDouble(Object o, long offset, double newValue) {
2855 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
2856 return Double.longBitsToDouble(v);
2857 }
2858
2859 @ForceInline
2860 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
2861 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
2862 return Double.longBitsToDouble(v);
2863 }
2864
2865 @ForceInline
2866 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
2867 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
2868 return Double.longBitsToDouble(v);
2869 }
2870
2871
2872 // The following contain CAS-based Java implementations used on
2873 // platforms not supporting native instructions
2874
2875 @ForceInline
2876 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
2877 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
2878 }
2879
2880 @ForceInline
2881 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
2882 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
2883 }
2884
2885 @ForceInline
2886 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
2887 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
2888 }
2889
2890 @ForceInline
2891 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
2892 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
2893 }
2894
2895 @ForceInline
2896 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
2897 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
2898 }
2899
2900 @ForceInline
2901 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
2902 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
2903 }
2904
2905 @ForceInline
2906 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
2907 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
2908 }
2909
2910 @ForceInline
2911 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
2912 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
2913 }
2914
2915 @ForceInline
2916 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
2917 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
2918 }
2919
2920
2921 @ForceInline
2922 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
2923 byte current;
2924 do {
2925 current = getByteVolatile(o, offset);
2926 } while (!weakCompareAndSetByte(o, offset,
2927 current, (byte) (current | mask)));
2928 return current;
2929 }
2930
2931 @ForceInline
2932 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
2933 byte current;
2934 do {
2935 current = getByte(o, offset);
2936 } while (!weakCompareAndSetByteRelease(o, offset,
2937 current, (byte) (current | mask)));
2938 return current;
2939 }
2940
2941 @ForceInline
2942 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
2943 byte current;
2944 do {
2945 // Plain read, the value is a hint, the acquire CAS does the work
2946 current = getByte(o, offset);
2947 } while (!weakCompareAndSetByteAcquire(o, offset,
2948 current, (byte) (current | mask)));
2949 return current;
2950 }
2951
2952 @ForceInline
2953 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
2954 byte current;
2955 do {
2956 current = getByteVolatile(o, offset);
2957 } while (!weakCompareAndSetByte(o, offset,
2958 current, (byte) (current & mask)));
2959 return current;
2960 }
2961
2962 @ForceInline
2963 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
2964 byte current;
2965 do {
2966 current = getByte(o, offset);
2967 } while (!weakCompareAndSetByteRelease(o, offset,
2968 current, (byte) (current & mask)));
2969 return current;
2970 }
2971
2972 @ForceInline
2973 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
2974 byte current;
2975 do {
2976 // Plain read, the value is a hint, the acquire CAS does the work
2977 current = getByte(o, offset);
2978 } while (!weakCompareAndSetByteAcquire(o, offset,
2979 current, (byte) (current & mask)));
2980 return current;
2981 }
2982
2983 @ForceInline
2984 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
2985 byte current;
2986 do {
2987 current = getByteVolatile(o, offset);
2988 } while (!weakCompareAndSetByte(o, offset,
2989 current, (byte) (current ^ mask)));
2990 return current;
2991 }
2992
2993 @ForceInline
2994 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
2995 byte current;
2996 do {
2997 current = getByte(o, offset);
2998 } while (!weakCompareAndSetByteRelease(o, offset,
2999 current, (byte) (current ^ mask)));
3000 return current;
3001 }
3002
3003 @ForceInline
3004 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3005 byte current;
3006 do {
3007 // Plain read, the value is a hint, the acquire CAS does the work
3008 current = getByte(o, offset);
3009 } while (!weakCompareAndSetByteAcquire(o, offset,
3010 current, (byte) (current ^ mask)));
3011 return current;
3012 }
3013
3014
3015 @ForceInline
3016 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3017 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3018 }
3019
3020 @ForceInline
3021 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3022 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3023 }
3024
3025 @ForceInline
3026 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3027 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3028 }
3029
3030 @ForceInline
3031 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3032 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3033 }
3034
3035 @ForceInline
3036 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3037 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3038 }
3039
3040 @ForceInline
3041 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3042 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3043 }
3044
3045 @ForceInline
3046 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3047 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3048 }
3049
3050 @ForceInline
3051 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3052 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3053 }
3054
3055 @ForceInline
3056 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3057 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3058 }
3059
3060
3061 @ForceInline
3062 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3063 short current;
3064 do {
3065 current = getShortVolatile(o, offset);
3066 } while (!weakCompareAndSetShort(o, offset,
3067 current, (short) (current | mask)));
3068 return current;
3069 }
3070
3071 @ForceInline
3072 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3073 short current;
3074 do {
3075 current = getShort(o, offset);
3076 } while (!weakCompareAndSetShortRelease(o, offset,
3077 current, (short) (current | mask)));
3078 return current;
3079 }
3080
3081 @ForceInline
3082 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3083 short current;
3084 do {
3085 // Plain read, the value is a hint, the acquire CAS does the work
3086 current = getShort(o, offset);
3087 } while (!weakCompareAndSetShortAcquire(o, offset,
3088 current, (short) (current | mask)));
3089 return current;
3090 }
3091
3092 @ForceInline
3093 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3094 short current;
3095 do {
3096 current = getShortVolatile(o, offset);
3097 } while (!weakCompareAndSetShort(o, offset,
3098 current, (short) (current & mask)));
3099 return current;
3100 }
3101
3102 @ForceInline
3103 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3104 short current;
3105 do {
3106 current = getShort(o, offset);
3107 } while (!weakCompareAndSetShortRelease(o, offset,
3108 current, (short) (current & mask)));
3109 return current;
3110 }
3111
3112 @ForceInline
3113 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3114 short current;
3115 do {
3116 // Plain read, the value is a hint, the acquire CAS does the work
3117 current = getShort(o, offset);
3118 } while (!weakCompareAndSetShortAcquire(o, offset,
3119 current, (short) (current & mask)));
3120 return current;
3121 }
3122
3123 @ForceInline
3124 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3125 short current;
3126 do {
3127 current = getShortVolatile(o, offset);
3128 } while (!weakCompareAndSetShort(o, offset,
3129 current, (short) (current ^ mask)));
3130 return current;
3131 }
3132
3133 @ForceInline
3134 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3135 short current;
3136 do {
3137 current = getShort(o, offset);
3138 } while (!weakCompareAndSetShortRelease(o, offset,
3139 current, (short) (current ^ mask)));
3140 return current;
3141 }
3142
3143 @ForceInline
3144 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3145 short current;
3146 do {
3147 // Plain read, the value is a hint, the acquire CAS does the work
3148 current = getShort(o, offset);
3149 } while (!weakCompareAndSetShortAcquire(o, offset,
3150 current, (short) (current ^ mask)));
3151 return current;
3152 }
3153
3154
3155 @ForceInline
3156 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3157 int current;
3158 do {
3159 current = getIntVolatile(o, offset);
3160 } while (!weakCompareAndSetInt(o, offset,
3161 current, current | mask));
3162 return current;
3163 }
3164
3165 @ForceInline
3166 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3167 int current;
3168 do {
3169 current = getInt(o, offset);
3170 } while (!weakCompareAndSetIntRelease(o, offset,
3171 current, current | mask));
3172 return current;
3173 }
3174
3175 @ForceInline
3176 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3177 int current;
3178 do {
3179 // Plain read, the value is a hint, the acquire CAS does the work
3180 current = getInt(o, offset);
3181 } while (!weakCompareAndSetIntAcquire(o, offset,
3182 current, current | mask));
3183 return current;
3184 }
3185
3186 /**
3187 * Atomically replaces the current value of a field or array element within
3188 * the given object with the result of bitwise AND between the current value
3189 * and mask.
3190 *
3191 * @param o object/array to update the field/element in
3192 * @param offset field/element offset
3193 * @param mask the mask value
3194 * @return the previous value
3195 * @since 1.9
3196 */
3197 @ForceInline
3198 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3199 int current;
3200 do {
3201 current = getIntVolatile(o, offset);
3202 } while (!weakCompareAndSetInt(o, offset,
3203 current, current & mask));
3204 return current;
3205 }
3206
3207 @ForceInline
3208 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3209 int current;
3210 do {
3211 current = getInt(o, offset);
3212 } while (!weakCompareAndSetIntRelease(o, offset,
3213 current, current & mask));
3214 return current;
3215 }
3216
3217 @ForceInline
3218 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3219 int current;
3220 do {
3221 // Plain read, the value is a hint, the acquire CAS does the work
3222 current = getInt(o, offset);
3223 } while (!weakCompareAndSetIntAcquire(o, offset,
3224 current, current & mask));
3225 return current;
3226 }
3227
3228 @ForceInline
3229 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3230 int current;
3231 do {
3232 current = getIntVolatile(o, offset);
3233 } while (!weakCompareAndSetInt(o, offset,
3234 current, current ^ mask));
3235 return current;
3236 }
3237
3238 @ForceInline
3239 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3240 int current;
3241 do {
3242 current = getInt(o, offset);
3243 } while (!weakCompareAndSetIntRelease(o, offset,
3244 current, current ^ mask));
3245 return current;
3246 }
3247
3248 @ForceInline
3249 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3250 int current;
3251 do {
3252 // Plain read, the value is a hint, the acquire CAS does the work
3253 current = getInt(o, offset);
3254 } while (!weakCompareAndSetIntAcquire(o, offset,
3255 current, current ^ mask));
3256 return current;
3257 }
3258
3259
3260 @ForceInline
3261 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3262 long current;
3263 do {
3264 current = getLongVolatile(o, offset);
3265 } while (!weakCompareAndSetLong(o, offset,
3266 current, current | mask));
3267 return current;
3268 }
3269
3270 @ForceInline
3271 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3272 long current;
3273 do {
3274 current = getLong(o, offset);
3275 } while (!weakCompareAndSetLongRelease(o, offset,
3276 current, current | mask));
3277 return current;
3278 }
3279
3280 @ForceInline
3281 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3282 long current;
3283 do {
3284 // Plain read, the value is a hint, the acquire CAS does the work
3285 current = getLong(o, offset);
3286 } while (!weakCompareAndSetLongAcquire(o, offset,
3287 current, current | mask));
3288 return current;
3289 }
3290
3291 @ForceInline
3292 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3293 long current;
3294 do {
3295 current = getLongVolatile(o, offset);
3296 } while (!weakCompareAndSetLong(o, offset,
3297 current, current & mask));
3298 return current;
3299 }
3300
3301 @ForceInline
3302 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3303 long current;
3304 do {
3305 current = getLong(o, offset);
3306 } while (!weakCompareAndSetLongRelease(o, offset,
3307 current, current & mask));
3308 return current;
3309 }
3310
3311 @ForceInline
3312 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3313 long current;
3314 do {
3315 // Plain read, the value is a hint, the acquire CAS does the work
3316 current = getLong(o, offset);
3317 } while (!weakCompareAndSetLongAcquire(o, offset,
3318 current, current & mask));
3319 return current;
3320 }
3321
3322 @ForceInline
3323 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3324 long current;
3325 do {
3326 current = getLongVolatile(o, offset);
3327 } while (!weakCompareAndSetLong(o, offset,
3328 current, current ^ mask));
3329 return current;
3330 }
3331
3332 @ForceInline
3333 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3334 long current;
3335 do {
3336 current = getLong(o, offset);
3337 } while (!weakCompareAndSetLongRelease(o, offset,
3338 current, current ^ mask));
3339 return current;
3340 }
3341
3342 @ForceInline
3343 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3344 long current;
3345 do {
3346 // Plain read, the value is a hint, the acquire CAS does the work
3347 current = getLong(o, offset);
3348 } while (!weakCompareAndSetLongAcquire(o, offset,
3349 current, current ^ mask));
3350 return current;
3351 }
3352
3353
3354
3355 /**
3356 * Ensures that loads before the fence will not be reordered with loads and
3357 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3358 *
3359 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3360 * (an "acquire fence").
3361 *
3362 * A pure LoadLoad fence is not provided, since the addition of LoadStore
3363 * is almost always desired, and most current hardware instructions that
3364 * provide a LoadLoad barrier also provide a LoadStore barrier for free.
3365 * @since 1.8
3366 */
3367 @HotSpotIntrinsicCandidate
3368 public native void loadFence();
3369
3370 /**
3371 * Ensures that loads and stores before the fence will not be reordered with
3372 * stores after the fence; a "StoreStore plus LoadStore barrier".
3373 *
3374 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3375 * (a "release fence").
3376 *
3377 * A pure StoreStore fence is not provided, since the addition of LoadStore
3378 * is almost always desired, and most current hardware instructions that
3379 * provide a StoreStore barrier also provide a LoadStore barrier for free.
3380 * @since 1.8
3381 */
3382 @HotSpotIntrinsicCandidate
3383 public native void storeFence();
3384
3385 /**
3386 * Ensures that loads and stores before the fence will not be reordered
3387 * with loads and stores after the fence. Implies the effects of both
3388 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3389 * barrier.
3390 *
3391 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3392 * @since 1.8
3393 */
3394 @HotSpotIntrinsicCandidate
3395 public native void fullFence();
3396
3397 /**
3398 * Ensures that loads before the fence will not be reordered with
3399 * loads after the fence.
3400 */
3401 public final void loadLoadFence() {
3402 loadFence();
3403 }
3404
3405 /**
3406 * Ensures that stores before the fence will not be reordered with
3407 * stores after the fence.
3408 */
3409 public final void storeStoreFence() {
3410 storeFence();
3411 }
3412
3413
3414 /**
3415 * Throws IllegalAccessError; for use by the VM for access control
3416 * error support.
3417 * @since 1.8
3418 */
3419 private static void throwIllegalAccessError() {
3420 throw new IllegalAccessError();
3421 }
3422
3423 /**
3424 * @return Returns true if the native byte ordering of this
3425 * platform is big-endian, false if it is little-endian.
3426 */
3427 public final boolean isBigEndian() { return BE; }
3428
3429 /**
3430 * @return Returns true if this platform is capable of performing
3431 * accesses at addresses which are not aligned for the type of the
3432 * primitive type being accessed, false otherwise.
3433 */
3434 public final boolean unalignedAccess() { return unalignedAccess; }
3435
3436 /**
3437 * Fetches a value at some byte offset into a given Java object.
3438 * More specifically, fetches a value within the given object
3439 * <code>o</code> at the given offset, or (if <code>o</code> is
3440 * null) from the memory address whose numerical value is the
3441 * given offset. <p>
3442 *
3443 * The specification of this method is the same as {@link
3444 * #getLong(Object, long)} except that the offset does not need to
3445 * have been obtained from {@link #objectFieldOffset} on the
3446 * {@link java.lang.reflect.Field} of some Java field. The value
3447 * in memory is raw data, and need not correspond to any Java
3448 * variable. Unless <code>o</code> is null, the value accessed
3449 * must be entirely within the allocated object. The endianness
3450 * of the value in memory is the endianness of the native platform.
3451 *
3452 * <p> The read will be atomic with respect to the largest power
3453 * of two that divides the GCD of the offset and the storage size.
3454 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3455 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3456 * respectively. There are no other guarantees of atomicity.
3457 * <p>
3458 * 8-byte atomicity is only guaranteed on platforms on which
3459 * support atomic accesses to longs.
3460 *
3461 * @param o Java heap object in which the value resides, if any, else
3462 * null
3463 * @param offset The offset in bytes from the start of the object
3464 * @return the value fetched from the indicated object
3465 * @throws RuntimeException No defined exceptions are thrown, not even
3466 * {@link NullPointerException}
3467 * @since 9
3468 */
3469 @HotSpotIntrinsicCandidate
3470 public final long getLongUnaligned(Object o, long offset) {
3471 if ((offset & 7) == 0) {
3472 return getLong(o, offset);
3473 } else if ((offset & 3) == 0) {
3474 return makeLong(getInt(o, offset),
3475 getInt(o, offset + 4));
3476 } else if ((offset & 1) == 0) {
3477 return makeLong(getShort(o, offset),
3478 getShort(o, offset + 2),
3479 getShort(o, offset + 4),
3480 getShort(o, offset + 6));
3481 } else {
3482 return makeLong(getByte(o, offset),
3483 getByte(o, offset + 1),
3484 getByte(o, offset + 2),
3485 getByte(o, offset + 3),
3486 getByte(o, offset + 4),
3487 getByte(o, offset + 5),
3488 getByte(o, offset + 6),
3489 getByte(o, offset + 7));
3490 }
3491 }
3492 /**
3493 * As {@link #getLongUnaligned(Object, long)} but with an
3494 * additional argument which specifies the endianness of the value
3495 * as stored in memory.
3496 *
3497 * @param o Java heap object in which the variable resides
3498 * @param offset The offset in bytes from the start of the object
3499 * @param bigEndian The endianness of the value
3500 * @return the value fetched from the indicated object
3501 * @since 9
3502 */
3503 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3504 return convEndian(bigEndian, getLongUnaligned(o, offset));
3505 }
3506
3507 /** @see #getLongUnaligned(Object, long) */
3508 @HotSpotIntrinsicCandidate
3509 public final int getIntUnaligned(Object o, long offset) {
3510 if ((offset & 3) == 0) {
3511 return getInt(o, offset);
3512 } else if ((offset & 1) == 0) {
3513 return makeInt(getShort(o, offset),
3514 getShort(o, offset + 2));
3515 } else {
3516 return makeInt(getByte(o, offset),
3517 getByte(o, offset + 1),
3518 getByte(o, offset + 2),
3519 getByte(o, offset + 3));
3520 }
3521 }
3522 /** @see #getLongUnaligned(Object, long, boolean) */
3523 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3524 return convEndian(bigEndian, getIntUnaligned(o, offset));
3525 }
3526
3527 /** @see #getLongUnaligned(Object, long) */
3528 @HotSpotIntrinsicCandidate
3529 public final short getShortUnaligned(Object o, long offset) {
3530 if ((offset & 1) == 0) {
3531 return getShort(o, offset);
3532 } else {
3533 return makeShort(getByte(o, offset),
3534 getByte(o, offset + 1));
3535 }
3536 }
3537 /** @see #getLongUnaligned(Object, long, boolean) */
3538 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3539 return convEndian(bigEndian, getShortUnaligned(o, offset));
3540 }
3541
3542 /** @see #getLongUnaligned(Object, long) */
3543 @HotSpotIntrinsicCandidate
3544 public final char getCharUnaligned(Object o, long offset) {
3545 if ((offset & 1) == 0) {
3546 return getChar(o, offset);
3547 } else {
3548 return (char)makeShort(getByte(o, offset),
3549 getByte(o, offset + 1));
3550 }
3551 }
3552
3553 /** @see #getLongUnaligned(Object, long, boolean) */
3554 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3555 return convEndian(bigEndian, getCharUnaligned(o, offset));
3556 }
3557
3558 /**
3559 * Stores a value at some byte offset into a given Java object.
3560 * <p>
3561 * The specification of this method is the same as {@link
3562 * #getLong(Object, long)} except that the offset does not need to
3563 * have been obtained from {@link #objectFieldOffset} on the
3564 * {@link java.lang.reflect.Field} of some Java field. The value
3565 * in memory is raw data, and need not correspond to any Java
3566 * variable. The endianness of the value in memory is the
3567 * endianness of the native platform.
3568 * <p>
3569 * The write will be atomic with respect to the largest power of
3570 * two that divides the GCD of the offset and the storage size.
3571 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3572 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3573 * respectively. There are no other guarantees of atomicity.
3574 * <p>
3575 * 8-byte atomicity is only guaranteed on platforms on which
3576 * support atomic accesses to longs.
3577 *
3578 * @param o Java heap object in which the value resides, if any, else
3579 * null
3580 * @param offset The offset in bytes from the start of the object
3581 * @param x the value to store
3582 * @throws RuntimeException No defined exceptions are thrown, not even
3583 * {@link NullPointerException}
3584 * @since 9
3585 */
3586 @HotSpotIntrinsicCandidate
3587 public final void putLongUnaligned(Object o, long offset, long x) {
3588 if ((offset & 7) == 0) {
3589 putLong(o, offset, x);
3590 } else if ((offset & 3) == 0) {
3591 putLongParts(o, offset,
3592 (int)(x >> 0),
3593 (int)(x >>> 32));
3594 } else if ((offset & 1) == 0) {
3595 putLongParts(o, offset,
3596 (short)(x >>> 0),
3597 (short)(x >>> 16),
3598 (short)(x >>> 32),
3599 (short)(x >>> 48));
3600 } else {
3601 putLongParts(o, offset,
3602 (byte)(x >>> 0),
3603 (byte)(x >>> 8),
3604 (byte)(x >>> 16),
3605 (byte)(x >>> 24),
3606 (byte)(x >>> 32),
3607 (byte)(x >>> 40),
3608 (byte)(x >>> 48),
3609 (byte)(x >>> 56));
3610 }
3611 }
3612
3613 /**
3614 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3615 * argument which specifies the endianness of the value as stored in memory.
3616 * @param o Java heap object in which the value resides
3617 * @param offset The offset in bytes from the start of the object
3618 * @param x the value to store
3619 * @param bigEndian The endianness of the value
3620 * @throws RuntimeException No defined exceptions are thrown, not even
3621 * {@link NullPointerException}
3622 * @since 9
3623 */
3624 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3625 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3626 }
3627
3628 /** @see #putLongUnaligned(Object, long, long) */
3629 @HotSpotIntrinsicCandidate
3630 public final void putIntUnaligned(Object o, long offset, int x) {
3631 if ((offset & 3) == 0) {
3632 putInt(o, offset, x);
3633 } else if ((offset & 1) == 0) {
3634 putIntParts(o, offset,
3635 (short)(x >> 0),
3636 (short)(x >>> 16));
3637 } else {
3638 putIntParts(o, offset,
3639 (byte)(x >>> 0),
3640 (byte)(x >>> 8),
3641 (byte)(x >>> 16),
3642 (byte)(x >>> 24));
3643 }
3644 }
3645 /** @see #putLongUnaligned(Object, long, long, boolean) */
3646 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3647 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3648 }
3649
3650 /** @see #putLongUnaligned(Object, long, long) */
3651 @HotSpotIntrinsicCandidate
3652 public final void putShortUnaligned(Object o, long offset, short x) {
3653 if ((offset & 1) == 0) {
3654 putShort(o, offset, x);
3655 } else {
3656 putShortParts(o, offset,
3657 (byte)(x >>> 0),
3658 (byte)(x >>> 8));
3659 }
3660 }
3661 /** @see #putLongUnaligned(Object, long, long, boolean) */
3662 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3663 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3664 }
3665
3666 /** @see #putLongUnaligned(Object, long, long) */
3667 @HotSpotIntrinsicCandidate
3668 public final void putCharUnaligned(Object o, long offset, char x) {
3669 putShortUnaligned(o, offset, (short)x);
3670 }
3671 /** @see #putLongUnaligned(Object, long, long, boolean) */
3672 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3673 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3674 }
3675
3676 // JVM interface methods
3677 // BE is true iff the native endianness of this platform is big.
3678 private static final boolean BE = theUnsafe.isBigEndian0();
3679
3680 // unalignedAccess is true iff this platform can perform unaligned accesses.
3681 private static final boolean unalignedAccess = theUnsafe.unalignedAccess0();
3682
3683 private static int pickPos(int top, int pos) { return BE ? top - pos : pos; }
3684
3685 // These methods construct integers from bytes. The byte ordering
3686 // is the native endianness of this platform.
3687 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3688 return ((toUnsignedLong(i0) << pickPos(56, 0))
3689 | (toUnsignedLong(i1) << pickPos(56, 8))
3690 | (toUnsignedLong(i2) << pickPos(56, 16))
3691 | (toUnsignedLong(i3) << pickPos(56, 24))
3692 | (toUnsignedLong(i4) << pickPos(56, 32))
3693 | (toUnsignedLong(i5) << pickPos(56, 40))
3694 | (toUnsignedLong(i6) << pickPos(56, 48))
3695 | (toUnsignedLong(i7) << pickPos(56, 56)));
3696 }
3697 private static long makeLong(short i0, short i1, short i2, short i3) {
3698 return ((toUnsignedLong(i0) << pickPos(48, 0))
3699 | (toUnsignedLong(i1) << pickPos(48, 16))
3700 | (toUnsignedLong(i2) << pickPos(48, 32))
3701 | (toUnsignedLong(i3) << pickPos(48, 48)));
3702 }
3703 private static long makeLong(int i0, int i1) {
3704 return (toUnsignedLong(i0) << pickPos(32, 0))
3705 | (toUnsignedLong(i1) << pickPos(32, 32));
3706 }
3707 private static int makeInt(short i0, short i1) {
3708 return (toUnsignedInt(i0) << pickPos(16, 0))
3709 | (toUnsignedInt(i1) << pickPos(16, 16));
3710 }
3711 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3712 return ((toUnsignedInt(i0) << pickPos(24, 0))
3713 | (toUnsignedInt(i1) << pickPos(24, 8))
3714 | (toUnsignedInt(i2) << pickPos(24, 16))
3715 | (toUnsignedInt(i3) << pickPos(24, 24)));
3716 }
3717 private static short makeShort(byte i0, byte i1) {
3718 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3719 | (toUnsignedInt(i1) << pickPos(8, 8)));
3720 }
3721
3722 private static byte pick(byte le, byte be) { return BE ? be : le; }
3723 private static short pick(short le, short be) { return BE ? be : le; }
3724 private static int pick(int le, int be) { return BE ? be : le; }
3725
3726 // These methods write integers to memory from smaller parts
3727 // provided by their caller. The ordering in which these parts
3728 // are written is the native endianness of this platform.
3729 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3730 putByte(o, offset + 0, pick(i0, i7));
3731 putByte(o, offset + 1, pick(i1, i6));
3732 putByte(o, offset + 2, pick(i2, i5));
3733 putByte(o, offset + 3, pick(i3, i4));
3734 putByte(o, offset + 4, pick(i4, i3));
3735 putByte(o, offset + 5, pick(i5, i2));
3736 putByte(o, offset + 6, pick(i6, i1));
3737 putByte(o, offset + 7, pick(i7, i0));
3738 }
3739 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3740 putShort(o, offset + 0, pick(i0, i3));
3741 putShort(o, offset + 2, pick(i1, i2));
3742 putShort(o, offset + 4, pick(i2, i1));
3743 putShort(o, offset + 6, pick(i3, i0));
3744 }
3745 private void putLongParts(Object o, long offset, int i0, int i1) {
3746 putInt(o, offset + 0, pick(i0, i1));
3747 putInt(o, offset + 4, pick(i1, i0));
3748 }
3749 private void putIntParts(Object o, long offset, short i0, short i1) {
3750 putShort(o, offset + 0, pick(i0, i1));
3751 putShort(o, offset + 2, pick(i1, i0));
3752 }
3753 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3754 putByte(o, offset + 0, pick(i0, i3));
3755 putByte(o, offset + 1, pick(i1, i2));
3756 putByte(o, offset + 2, pick(i2, i1));
3757 putByte(o, offset + 3, pick(i3, i0));
3758 }
3759 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3760 putByte(o, offset + 0, pick(i0, i1));
3761 putByte(o, offset + 1, pick(i1, i0));
3762 }
3763
3764 // Zero-extend an integer
3765 private static int toUnsignedInt(byte n) { return n & 0xff; }
3766 private static int toUnsignedInt(short n) { return n & 0xffff; }
3767 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3768 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3769 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3770
3771 // Maybe byte-reverse an integer
3772 private static char convEndian(boolean big, char n) { return big == BE ? n : Character.reverseBytes(n); }
3773 private static short convEndian(boolean big, short n) { return big == BE ? n : Short.reverseBytes(n) ; }
3774 private static int convEndian(boolean big, int n) { return big == BE ? n : Integer.reverseBytes(n) ; }
3775 private static long convEndian(boolean big, long n) { return big == BE ? n : Long.reverseBytes(n) ; }
3776
3777
3778
3779 private native long allocateMemory0(long bytes);
3780 private native long reallocateMemory0(long address, long bytes);
3781 private native void freeMemory0(long address);
3782 private native void setMemory0(Object o, long offset, long bytes, byte value);
3783 @HotSpotIntrinsicCandidate
3784 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3785 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3786 private native long objectFieldOffset0(Field f);
3787 private native long objectFieldOffset1(Class<?> c, String name);
3788 private native long staticFieldOffset0(Field f);
3789 private native Object staticFieldBase0(Field f);
3790 private native boolean shouldBeInitialized0(Class<?> c);
3791 private native void ensureClassInitialized0(Class<?> c);
3792 private native int arrayBaseOffset0(Class<?> arrayClass);
3793 private native int arrayIndexScale0(Class<?> arrayClass);
3794 private native int addressSize0();
3795 private native int dataCacheLineFlushSize0();
3796 private native Class<?> defineAnonymousClass0(Class<?> hostClass, byte[] data, Object[] cpPatches);
3797 private native int getLoadAverage0(double[] loadavg, int nelems);
3798 private native boolean unalignedAccess0();
3799 private native boolean isBigEndian0();
3800 }