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 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 /// random queries
922
923 /**
924 * This constant differs from all results that will ever be returned from
925 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
926 * or {@link #arrayBaseOffset}.
927 */
928 public static final int INVALID_FIELD_OFFSET = -1;
929
930 /**
931 * Reports the location of a given field in the storage allocation of its
932 * class. Do not expect to perform any sort of arithmetic on this offset;
933 * it is just a cookie which is passed to the unsafe heap memory accessors.
934 *
935 * <p>Any given field will always have the same offset and base, and no
936 * two distinct fields of the same class will ever have the same offset
937 * and base.
938 *
939 * <p>As of 1.4.1, offsets for fields are represented as long values,
940 * although the Sun JVM does not use the most significant 32 bits.
941 * However, JVM implementations which store static fields at absolute
942 * addresses can use long offsets and null base pointers to express
943 * the field locations in a form usable by {@link #getInt(Object,long)}.
944 * Therefore, code which will be ported to such JVMs on 64-bit platforms
945 * must preserve all bits of static field offsets.
946 * @see #getInt(Object, long)
947 */
948 public long objectFieldOffset(Field f) {
949 if (f == null) {
950 throw new NullPointerException();
951 }
952
953 return objectFieldOffset0(f);
954 }
955
956 /**
957 * Reports the location of a given static field, in conjunction with {@link
958 * #staticFieldBase}.
959 * <p>Do not expect to perform any sort of arithmetic on this offset;
960 * it is just a cookie which is passed to the unsafe heap memory accessors.
961 *
962 * <p>Any given field will always have the same offset, and no two distinct
963 * fields of the same class will ever have the same offset.
964 *
965 * <p>As of 1.4.1, offsets for fields are represented as long values,
966 * although the Sun JVM does not use the most significant 32 bits.
967 * It is hard to imagine a JVM technology which needs more than
968 * a few bits to encode an offset within a non-array object,
969 * However, for consistency with other methods in this class,
970 * this method reports its result as a long value.
971 * @see #getInt(Object, long)
972 */
973 public long staticFieldOffset(Field f) {
974 if (f == null) {
975 throw new NullPointerException();
976 }
977
978 return staticFieldOffset0(f);
979 }
980
981 /**
982 * Reports the location of a given static field, in conjunction with {@link
983 * #staticFieldOffset}.
984 * <p>Fetch the base "Object", if any, with which static fields of the
985 * given class can be accessed via methods like {@link #getInt(Object,
986 * long)}. This value may be null. This value may refer to an object
987 * which is a "cookie", not guaranteed to be a real Object, and it should
988 * not be used in any way except as argument to the get and put routines in
989 * this class.
990 */
991 public Object staticFieldBase(Field f) {
992 if (f == null) {
993 throw new NullPointerException();
994 }
995
996 return staticFieldBase0(f);
997 }
998
999 /**
1000 * Detects if the given class may need to be initialized. This is often
1001 * needed in conjunction with obtaining the static field base of a
1002 * class.
1003 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1004 */
1005 public boolean shouldBeInitialized(Class<?> c) {
1006 if (c == null) {
1007 throw new NullPointerException();
1008 }
1009
1010 return shouldBeInitialized0(c);
1011 }
1012
1013 /**
1014 * Ensures the given class has been initialized. This is often
1015 * needed in conjunction with obtaining the static field base of a
1016 * class.
1017 */
1018 public void ensureClassInitialized(Class<?> c) {
1019 if (c == null) {
1020 throw new NullPointerException();
1021 }
1022
1023 ensureClassInitialized0(c);
1024 }
1025
1026 /**
1027 * Reports the offset of the first element in the storage allocation of a
1028 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1029 * for the same class, you may use that scale factor, together with this
1030 * base offset, to form new offsets to access elements of arrays of the
1031 * given class.
1032 *
1033 * @see #getInt(Object, long)
1034 * @see #putInt(Object, long, int)
1035 */
1036 public int arrayBaseOffset(Class<?> arrayClass) {
1037 if (arrayClass == null) {
1038 throw new NullPointerException();
1039 }
1040
1041 return arrayBaseOffset0(arrayClass);
1042 }
1043
1044
1045 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1046 public static final int ARRAY_BOOLEAN_BASE_OFFSET
1047 = theUnsafe.arrayBaseOffset(boolean[].class);
1048
1049 /** The value of {@code arrayBaseOffset(byte[].class)} */
1050 public static final int ARRAY_BYTE_BASE_OFFSET
1051 = theUnsafe.arrayBaseOffset(byte[].class);
1052
1053 /** The value of {@code arrayBaseOffset(short[].class)} */
1054 public static final int ARRAY_SHORT_BASE_OFFSET
1055 = theUnsafe.arrayBaseOffset(short[].class);
1056
1057 /** The value of {@code arrayBaseOffset(char[].class)} */
1058 public static final int ARRAY_CHAR_BASE_OFFSET
1059 = theUnsafe.arrayBaseOffset(char[].class);
1060
1061 /** The value of {@code arrayBaseOffset(int[].class)} */
1062 public static final int ARRAY_INT_BASE_OFFSET
1063 = theUnsafe.arrayBaseOffset(int[].class);
1064
1065 /** The value of {@code arrayBaseOffset(long[].class)} */
1066 public static final int ARRAY_LONG_BASE_OFFSET
1067 = theUnsafe.arrayBaseOffset(long[].class);
1068
1069 /** The value of {@code arrayBaseOffset(float[].class)} */
1070 public static final int ARRAY_FLOAT_BASE_OFFSET
1071 = theUnsafe.arrayBaseOffset(float[].class);
1072
1073 /** The value of {@code arrayBaseOffset(double[].class)} */
1074 public static final int ARRAY_DOUBLE_BASE_OFFSET
1075 = theUnsafe.arrayBaseOffset(double[].class);
1076
1077 /** The value of {@code arrayBaseOffset(Object[].class)} */
1078 public static final int ARRAY_OBJECT_BASE_OFFSET
1079 = theUnsafe.arrayBaseOffset(Object[].class);
1080
1081 /**
1082 * Reports the scale factor for addressing elements in the storage
1083 * allocation of a given array class. However, arrays of "narrow" types
1084 * will generally not work properly with accessors like {@link
1085 * #getByte(Object, long)}, so the scale factor for such classes is reported
1086 * as zero.
1087 *
1088 * @see #arrayBaseOffset
1089 * @see #getInt(Object, long)
1090 * @see #putInt(Object, long, int)
1091 */
1092 public int arrayIndexScale(Class<?> arrayClass) {
1093 if (arrayClass == null) {
1094 throw new NullPointerException();
1095 }
1096
1097 return arrayIndexScale0(arrayClass);
1098 }
1099
1100
1101 /** The value of {@code arrayIndexScale(boolean[].class)} */
1102 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1103 = theUnsafe.arrayIndexScale(boolean[].class);
1104
1105 /** The value of {@code arrayIndexScale(byte[].class)} */
1106 public static final int ARRAY_BYTE_INDEX_SCALE
1107 = theUnsafe.arrayIndexScale(byte[].class);
1108
1109 /** The value of {@code arrayIndexScale(short[].class)} */
1110 public static final int ARRAY_SHORT_INDEX_SCALE
1111 = theUnsafe.arrayIndexScale(short[].class);
1112
1113 /** The value of {@code arrayIndexScale(char[].class)} */
1114 public static final int ARRAY_CHAR_INDEX_SCALE
1115 = theUnsafe.arrayIndexScale(char[].class);
1116
1117 /** The value of {@code arrayIndexScale(int[].class)} */
1118 public static final int ARRAY_INT_INDEX_SCALE
1119 = theUnsafe.arrayIndexScale(int[].class);
1120
1121 /** The value of {@code arrayIndexScale(long[].class)} */
1122 public static final int ARRAY_LONG_INDEX_SCALE
1123 = theUnsafe.arrayIndexScale(long[].class);
1124
1125 /** The value of {@code arrayIndexScale(float[].class)} */
1126 public static final int ARRAY_FLOAT_INDEX_SCALE
1127 = theUnsafe.arrayIndexScale(float[].class);
1128
1129 /** The value of {@code arrayIndexScale(double[].class)} */
1130 public static final int ARRAY_DOUBLE_INDEX_SCALE
1131 = theUnsafe.arrayIndexScale(double[].class);
1132
1133 /** The value of {@code arrayIndexScale(Object[].class)} */
1134 public static final int ARRAY_OBJECT_INDEX_SCALE
1135 = theUnsafe.arrayIndexScale(Object[].class);
1136
1137 /**
1138 * Reports the size in bytes of a native pointer, as stored via {@link
1139 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1140 * other primitive types (as stored in native memory blocks) is determined
1141 * fully by their information content.
1142 */
1143 public int addressSize() {
1144 return ADDRESS_SIZE;
1145 }
1146
1147 /** The value of {@code addressSize()} */
1148 public static final int ADDRESS_SIZE = theUnsafe.addressSize0();
1149
1150 /**
1151 * Reports the size in bytes of a native memory page (whatever that is).
1152 * This value will always be a power of two.
1153 */
1154 public native int pageSize();
1155
1156
1157 /// random trusted operations from JNI:
1158
1159 /**
1160 * Tells the VM to define a class, without security checks. By default, the
1161 * class loader and protection domain come from the caller's class.
1162 */
1163 public Class<?> defineClass(String name, byte[] b, int off, int len,
1164 ClassLoader loader,
1165 ProtectionDomain protectionDomain) {
1166 if (b == null) {
1167 throw new NullPointerException();
1168 }
1169 if (len < 0) {
1170 throw new ArrayIndexOutOfBoundsException();
1171 }
1172
1173 return defineClass0(name, b, off, len, loader, protectionDomain);
1174 }
1175
1176 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1177 ClassLoader loader,
1178 ProtectionDomain protectionDomain);
1179
1180 /**
1181 * Defines a class but does not make it known to the class loader or system dictionary.
1182 * <p>
1183 * For each CP entry, the corresponding CP patch must either be null or have
1184 * the a format that matches its tag:
1185 * <ul>
1186 * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang
1187 * <li>Utf8: a string (must have suitable syntax if used as signature or name)
1188 * <li>Class: any java.lang.Class object
1189 * <li>String: any object (not just a java.lang.String)
1190 * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments
1191 * </ul>
1192 * @param hostClass context for linkage, access control, protection domain, and class loader
1193 * @param data bytes of a class file
1194 * @param cpPatches where non-null entries exist, they replace corresponding CP entries in data
1195 */
1196 public Class<?> defineAnonymousClass(Class<?> hostClass, byte[] data, Object[] cpPatches) {
1197 if (hostClass == null || data == null) {
1198 throw new NullPointerException();
1199 }
1200 if (hostClass.isArray() || hostClass.isPrimitive()) {
1201 throw new IllegalArgumentException();
1202 }
1203
1204 return defineAnonymousClass0(hostClass, data, cpPatches);
1205 }
1206
1207 /**
1208 * Allocates an instance but does not run any constructor.
1209 * Initializes the class if it has not yet been.
1210 */
1211 @HotSpotIntrinsicCandidate
1212 public native Object allocateInstance(Class<?> cls)
1213 throws InstantiationException;
1214
1215 /**
1216 * Allocates an array of a given type, but does not do zeroing.
1217 * <p>
1218 * This method should only be used in the very rare cases where a high-performance code
1219 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1220 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1221 * <p>
1222 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1223 * before allowing untrusted code, or code in other threads, to observe the reference
1224 * to the newly allocated array. In addition, the publication of the array reference must be
1225 * safe according to the Java Memory Model requirements.
1226 * <p>
1227 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1228 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1229 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1230 * or issuing a {@link #storeFence} before publishing the reference.
1231 * <p>
1232 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1233 * elements that could break heap integrity.
1234 *
1235 * @param componentType array component type to allocate
1236 * @param length array size to allocate
1237 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1238 * or the length is negative
1239 */
1240 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1241 if (componentType == null) {
1242 throw new IllegalArgumentException("Component type is null");
1243 }
1244 if (!componentType.isPrimitive()) {
1245 throw new IllegalArgumentException("Component type is not primitive");
1246 }
1247 if (length < 0) {
1248 throw new IllegalArgumentException("Negative length");
1249 }
1250 return allocateUninitializedArray0(componentType, length);
1251 }
1252
1253 @HotSpotIntrinsicCandidate
1254 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1255 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1256 // return the zeroed arrays.
1257 if (componentType == byte.class) return new byte[length];
1258 if (componentType == boolean.class) return new boolean[length];
1259 if (componentType == short.class) return new short[length];
1260 if (componentType == char.class) return new char[length];
1261 if (componentType == int.class) return new int[length];
1262 if (componentType == float.class) return new float[length];
1263 if (componentType == long.class) return new long[length];
1264 if (componentType == double.class) return new double[length];
1265 return null;
1266 }
1267
1268 /** Throws the exception without telling the verifier. */
1269 public native void throwException(Throwable ee);
1270
1271 /**
1272 * Atomically updates Java variable to {@code x} if it is currently
1273 * holding {@code expected}.
1274 *
1275 * <p>This operation has memory semantics of a {@code volatile} read
1276 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1277 *
1278 * @return {@code true} if successful
1279 */
1280 @HotSpotIntrinsicCandidate
1281 public final native boolean compareAndSetObject(Object o, long offset,
1282 Object expected,
1283 Object x);
1284
1285 @HotSpotIntrinsicCandidate
1286 public final native Object compareAndExchangeObject(Object o, long offset,
1287 Object expected,
1288 Object x);
1289
1290 @HotSpotIntrinsicCandidate
1291 public final Object compareAndExchangeObjectAcquire(Object o, long offset,
1292 Object expected,
1293 Object x) {
1294 return compareAndExchangeObject(o, offset, expected, x);
1295 }
1296
1297 @HotSpotIntrinsicCandidate
1298 public final Object compareAndExchangeObjectRelease(Object o, long offset,
1299 Object expected,
1300 Object x) {
1301 return compareAndExchangeObject(o, offset, expected, x);
1302 }
1303
1304 @HotSpotIntrinsicCandidate
1305 public final boolean weakCompareAndSetObjectPlain(Object o, long offset,
1306 Object expected,
1307 Object x) {
1308 return compareAndSetObject(o, offset, expected, x);
1309 }
1310
1311 @HotSpotIntrinsicCandidate
1312 public final boolean weakCompareAndSetObjectAcquire(Object o, long offset,
1313 Object expected,
1314 Object x) {
1315 return compareAndSetObject(o, offset, expected, x);
1316 }
1317
1318 @HotSpotIntrinsicCandidate
1319 public final boolean weakCompareAndSetObjectRelease(Object o, long offset,
1320 Object expected,
1321 Object x) {
1322 return compareAndSetObject(o, offset, expected, x);
1323 }
1324
1325 @HotSpotIntrinsicCandidate
1326 public final boolean weakCompareAndSetObject(Object o, long offset,
1327 Object expected,
1328 Object x) {
1329 return compareAndSetObject(o, offset, expected, x);
1330 }
1331
1332 /**
1333 * Atomically updates Java variable to {@code x} if it is currently
1334 * holding {@code expected}.
1335 *
1336 * <p>This operation has memory semantics of a {@code volatile} read
1337 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1338 *
1339 * @return {@code true} if successful
1340 */
1341 @HotSpotIntrinsicCandidate
1342 public final native boolean compareAndSetInt(Object o, long offset,
1343 int expected,
1344 int x);
1345
1346 @HotSpotIntrinsicCandidate
1347 public final native int compareAndExchangeInt(Object o, long offset,
1348 int expected,
1349 int x);
1350
1351 @HotSpotIntrinsicCandidate
1352 public final int compareAndExchangeIntAcquire(Object o, long offset,
1353 int expected,
1354 int x) {
1355 return compareAndExchangeInt(o, offset, expected, x);
1356 }
1357
1358 @HotSpotIntrinsicCandidate
1359 public final int compareAndExchangeIntRelease(Object o, long offset,
1360 int expected,
1361 int x) {
1362 return compareAndExchangeInt(o, offset, expected, x);
1363 }
1364
1365 @HotSpotIntrinsicCandidate
1366 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1367 int expected,
1368 int x) {
1369 return compareAndSetInt(o, offset, expected, x);
1370 }
1371
1372 @HotSpotIntrinsicCandidate
1373 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1374 int expected,
1375 int x) {
1376 return compareAndSetInt(o, offset, expected, x);
1377 }
1378
1379 @HotSpotIntrinsicCandidate
1380 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1381 int expected,
1382 int x) {
1383 return compareAndSetInt(o, offset, expected, x);
1384 }
1385
1386 @HotSpotIntrinsicCandidate
1387 public final boolean weakCompareAndSetInt(Object o, long offset,
1388 int expected,
1389 int x) {
1390 return compareAndSetInt(o, offset, expected, x);
1391 }
1392
1393 @HotSpotIntrinsicCandidate
1394 public final byte compareAndExchangeByte(Object o, long offset,
1395 byte expected,
1396 byte x) {
1397 long wordOffset = offset & ~3;
1398 int shift = (int) (offset & 3) << 3;
1399 if (BE) {
1400 shift = 24 - shift;
1401 }
1402 int mask = 0xFF << shift;
1403 int maskedExpected = (expected & 0xFF) << shift;
1404 int maskedX = (x & 0xFF) << shift;
1405 int fullWord;
1406 do {
1407 fullWord = getIntVolatile(o, wordOffset);
1408 if ((fullWord & mask) != maskedExpected)
1409 return (byte) ((fullWord & mask) >> shift);
1410 } while (!weakCompareAndSetInt(o, wordOffset,
1411 fullWord, (fullWord & ~mask) | maskedX));
1412 return expected;
1413 }
1414
1415 @HotSpotIntrinsicCandidate
1416 public final boolean compareAndSetByte(Object o, long offset,
1417 byte expected,
1418 byte x) {
1419 return compareAndExchangeByte(o, offset, expected, x) == expected;
1420 }
1421
1422 @HotSpotIntrinsicCandidate
1423 public final boolean weakCompareAndSetByte(Object o, long offset,
1424 byte expected,
1425 byte x) {
1426 return compareAndSetByte(o, offset, expected, x);
1427 }
1428
1429 @HotSpotIntrinsicCandidate
1430 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
1431 byte expected,
1432 byte x) {
1433 return weakCompareAndSetByte(o, offset, expected, x);
1434 }
1435
1436 @HotSpotIntrinsicCandidate
1437 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
1438 byte expected,
1439 byte x) {
1440 return weakCompareAndSetByte(o, offset, expected, x);
1441 }
1442
1443 @HotSpotIntrinsicCandidate
1444 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
1445 byte expected,
1446 byte x) {
1447 return weakCompareAndSetByte(o, offset, expected, x);
1448 }
1449
1450 @HotSpotIntrinsicCandidate
1451 public final byte compareAndExchangeByteAcquire(Object o, long offset,
1452 byte expected,
1453 byte x) {
1454 return compareAndExchangeByte(o, offset, expected, x);
1455 }
1456
1457 @HotSpotIntrinsicCandidate
1458 public final byte compareAndExchangeByteRelease(Object o, long offset,
1459 byte expected,
1460 byte x) {
1461 return compareAndExchangeByte(o, offset, expected, x);
1462 }
1463
1464 @HotSpotIntrinsicCandidate
1465 public final short compareAndExchangeShort(Object o, long offset,
1466 short expected,
1467 short x) {
1468 if ((offset & 3) == 3) {
1469 throw new IllegalArgumentException("Update spans the word, not supported");
1470 }
1471 long wordOffset = offset & ~3;
1472 int shift = (int) (offset & 3) << 3;
1473 if (BE) {
1474 shift = 16 - shift;
1475 }
1476 int mask = 0xFFFF << shift;
1477 int maskedExpected = (expected & 0xFFFF) << shift;
1478 int maskedX = (x & 0xFFFF) << shift;
1479 int fullWord;
1480 do {
1481 fullWord = getIntVolatile(o, wordOffset);
1482 if ((fullWord & mask) != maskedExpected) {
1483 return (short) ((fullWord & mask) >> shift);
1484 }
1485 } while (!weakCompareAndSetInt(o, wordOffset,
1486 fullWord, (fullWord & ~mask) | maskedX));
1487 return expected;
1488 }
1489
1490 @HotSpotIntrinsicCandidate
1491 public final boolean compareAndSetShort(Object o, long offset,
1492 short expected,
1493 short x) {
1494 return compareAndExchangeShort(o, offset, expected, x) == expected;
1495 }
1496
1497 @HotSpotIntrinsicCandidate
1498 public final boolean weakCompareAndSetShort(Object o, long offset,
1499 short expected,
1500 short x) {
1501 return compareAndSetShort(o, offset, expected, x);
1502 }
1503
1504 @HotSpotIntrinsicCandidate
1505 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
1506 short expected,
1507 short x) {
1508 return weakCompareAndSetShort(o, offset, expected, x);
1509 }
1510
1511 @HotSpotIntrinsicCandidate
1512 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
1513 short expected,
1514 short x) {
1515 return weakCompareAndSetShort(o, offset, expected, x);
1516 }
1517
1518 @HotSpotIntrinsicCandidate
1519 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
1520 short expected,
1521 short x) {
1522 return weakCompareAndSetShort(o, offset, expected, x);
1523 }
1524
1525
1526 @HotSpotIntrinsicCandidate
1527 public final short compareAndExchangeShortAcquire(Object o, long offset,
1528 short expected,
1529 short x) {
1530 return compareAndExchangeShort(o, offset, expected, x);
1531 }
1532
1533 @HotSpotIntrinsicCandidate
1534 public final short compareAndExchangeShortRelease(Object o, long offset,
1535 short expected,
1536 short x) {
1537 return compareAndExchangeShort(o, offset, expected, x);
1538 }
1539
1540 @ForceInline
1541 private char s2c(short s) {
1542 return (char) s;
1543 }
1544
1545 @ForceInline
1546 private short c2s(char s) {
1547 return (short) s;
1548 }
1549
1550 @ForceInline
1551 public final boolean compareAndSetChar(Object o, long offset,
1552 char expected,
1553 char x) {
1554 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
1555 }
1556
1557 @ForceInline
1558 public final char compareAndExchangeChar(Object o, long offset,
1559 char expected,
1560 char x) {
1561 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
1562 }
1563
1564 @ForceInline
1565 public final char compareAndExchangeCharAcquire(Object o, long offset,
1566 char expected,
1567 char x) {
1568 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
1569 }
1570
1571 @ForceInline
1572 public final char compareAndExchangeCharRelease(Object o, long offset,
1573 char expected,
1574 char x) {
1575 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
1576 }
1577
1578 @ForceInline
1579 public final boolean weakCompareAndSetChar(Object o, long offset,
1580 char expected,
1581 char x) {
1582 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
1583 }
1584
1585 @ForceInline
1586 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
1587 char expected,
1588 char x) {
1589 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
1590 }
1591
1592 @ForceInline
1593 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
1594 char expected,
1595 char x) {
1596 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
1597 }
1598
1599 @ForceInline
1600 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
1601 char expected,
1602 char x) {
1603 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
1604 }
1605
1606 /**
1607 * The JVM converts integral values to boolean values using two
1608 * different conventions, byte testing against zero and truncation
1609 * to least-significant bit.
1610 *
1611 * <p>The JNI documents specify that, at least for returning
1612 * values from native methods, a Java boolean value is converted
1613 * to the value-set 0..1 by first truncating to a byte (0..255 or
1614 * maybe -128..127) and then testing against zero. Thus, Java
1615 * booleans in non-Java data structures are by convention
1616 * represented as 8-bit containers containing either zero (for
1617 * false) or any non-zero value (for true).
1618 *
1619 * <p>Java booleans in the heap are also stored in bytes, but are
1620 * strongly normalized to the value-set 0..1 (i.e., they are
1621 * truncated to the least-significant bit).
1622 *
1623 * <p>The main reason for having different conventions for
1624 * conversion is performance: Truncation to the least-significant
1625 * bit can be usually implemented with fewer (machine)
1626 * instructions than byte testing against zero.
1627 *
1628 * <p>A number of Unsafe methods load boolean values from the heap
1629 * as bytes. Unsafe converts those values according to the JNI
1630 * rules (i.e, using the "testing against zero" convention). The
1631 * method {@code byte2bool} implements that conversion.
1632 *
1633 * @param b the byte to be converted to boolean
1634 * @return the result of the conversion
1635 */
1636 @ForceInline
1637 private boolean byte2bool(byte b) {
1638 return b != 0;
1639 }
1640
1641 /**
1642 * Convert a boolean value to a byte. The return value is strongly
1643 * normalized to the value-set 0..1 (i.e., the value is truncated
1644 * to the least-significant bit). See {@link #byte2bool(byte)} for
1645 * more details on conversion conventions.
1646 *
1647 * @param b the boolean to be converted to byte (and then normalized)
1648 * @return the result of the conversion
1649 */
1650 @ForceInline
1651 private byte bool2byte(boolean b) {
1652 return b ? (byte)1 : (byte)0;
1653 }
1654
1655 @ForceInline
1656 public final boolean compareAndSetBoolean(Object o, long offset,
1657 boolean expected,
1658 boolean x) {
1659 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1660 }
1661
1662 @ForceInline
1663 public final boolean compareAndExchangeBoolean(Object o, long offset,
1664 boolean expected,
1665 boolean x) {
1666 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
1667 }
1668
1669 @ForceInline
1670 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
1671 boolean expected,
1672 boolean x) {
1673 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
1674 }
1675
1676 @ForceInline
1677 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
1678 boolean expected,
1679 boolean x) {
1680 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
1681 }
1682
1683 @ForceInline
1684 public final boolean weakCompareAndSetBoolean(Object o, long offset,
1685 boolean expected,
1686 boolean x) {
1687 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
1688 }
1689
1690 @ForceInline
1691 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
1692 boolean expected,
1693 boolean x) {
1694 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
1695 }
1696
1697 @ForceInline
1698 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
1699 boolean expected,
1700 boolean x) {
1701 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
1702 }
1703
1704 @ForceInline
1705 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
1706 boolean expected,
1707 boolean x) {
1708 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
1709 }
1710
1711 /**
1712 * Atomically updates Java variable to {@code x} if it is currently
1713 * holding {@code expected}.
1714 *
1715 * <p>This operation has memory semantics of a {@code volatile} read
1716 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1717 *
1718 * @return {@code true} if successful
1719 */
1720 @ForceInline
1721 public final boolean compareAndSetFloat(Object o, long offset,
1722 float expected,
1723 float x) {
1724 return compareAndSetInt(o, offset,
1725 Float.floatToRawIntBits(expected),
1726 Float.floatToRawIntBits(x));
1727 }
1728
1729 @ForceInline
1730 public final float compareAndExchangeFloat(Object o, long offset,
1731 float expected,
1732 float x) {
1733 int w = compareAndExchangeInt(o, offset,
1734 Float.floatToRawIntBits(expected),
1735 Float.floatToRawIntBits(x));
1736 return Float.intBitsToFloat(w);
1737 }
1738
1739 @ForceInline
1740 public final float compareAndExchangeFloatAcquire(Object o, long offset,
1741 float expected,
1742 float x) {
1743 int w = compareAndExchangeIntAcquire(o, offset,
1744 Float.floatToRawIntBits(expected),
1745 Float.floatToRawIntBits(x));
1746 return Float.intBitsToFloat(w);
1747 }
1748
1749 @ForceInline
1750 public final float compareAndExchangeFloatRelease(Object o, long offset,
1751 float expected,
1752 float x) {
1753 int w = compareAndExchangeIntRelease(o, offset,
1754 Float.floatToRawIntBits(expected),
1755 Float.floatToRawIntBits(x));
1756 return Float.intBitsToFloat(w);
1757 }
1758
1759 @ForceInline
1760 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
1761 float expected,
1762 float x) {
1763 return weakCompareAndSetIntPlain(o, offset,
1764 Float.floatToRawIntBits(expected),
1765 Float.floatToRawIntBits(x));
1766 }
1767
1768 @ForceInline
1769 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
1770 float expected,
1771 float x) {
1772 return weakCompareAndSetIntAcquire(o, offset,
1773 Float.floatToRawIntBits(expected),
1774 Float.floatToRawIntBits(x));
1775 }
1776
1777 @ForceInline
1778 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
1779 float expected,
1780 float x) {
1781 return weakCompareAndSetIntRelease(o, offset,
1782 Float.floatToRawIntBits(expected),
1783 Float.floatToRawIntBits(x));
1784 }
1785
1786 @ForceInline
1787 public final boolean weakCompareAndSetFloat(Object o, long offset,
1788 float expected,
1789 float x) {
1790 return weakCompareAndSetInt(o, offset,
1791 Float.floatToRawIntBits(expected),
1792 Float.floatToRawIntBits(x));
1793 }
1794
1795 /**
1796 * Atomically updates Java variable to {@code x} if it is currently
1797 * holding {@code expected}.
1798 *
1799 * <p>This operation has memory semantics of a {@code volatile} read
1800 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1801 *
1802 * @return {@code true} if successful
1803 */
1804 @ForceInline
1805 public final boolean compareAndSetDouble(Object o, long offset,
1806 double expected,
1807 double x) {
1808 return compareAndSetLong(o, offset,
1809 Double.doubleToRawLongBits(expected),
1810 Double.doubleToRawLongBits(x));
1811 }
1812
1813 @ForceInline
1814 public final double compareAndExchangeDouble(Object o, long offset,
1815 double expected,
1816 double x) {
1817 long w = compareAndExchangeLong(o, offset,
1818 Double.doubleToRawLongBits(expected),
1819 Double.doubleToRawLongBits(x));
1820 return Double.longBitsToDouble(w);
1821 }
1822
1823 @ForceInline
1824 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
1825 double expected,
1826 double x) {
1827 long w = compareAndExchangeLongAcquire(o, offset,
1828 Double.doubleToRawLongBits(expected),
1829 Double.doubleToRawLongBits(x));
1830 return Double.longBitsToDouble(w);
1831 }
1832
1833 @ForceInline
1834 public final double compareAndExchangeDoubleRelease(Object o, long offset,
1835 double expected,
1836 double x) {
1837 long w = compareAndExchangeLongRelease(o, offset,
1838 Double.doubleToRawLongBits(expected),
1839 Double.doubleToRawLongBits(x));
1840 return Double.longBitsToDouble(w);
1841 }
1842
1843 @ForceInline
1844 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
1845 double expected,
1846 double x) {
1847 return weakCompareAndSetLongPlain(o, offset,
1848 Double.doubleToRawLongBits(expected),
1849 Double.doubleToRawLongBits(x));
1850 }
1851
1852 @ForceInline
1853 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
1854 double expected,
1855 double x) {
1856 return weakCompareAndSetLongAcquire(o, offset,
1857 Double.doubleToRawLongBits(expected),
1858 Double.doubleToRawLongBits(x));
1859 }
1860
1861 @ForceInline
1862 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
1863 double expected,
1864 double x) {
1865 return weakCompareAndSetLongRelease(o, offset,
1866 Double.doubleToRawLongBits(expected),
1867 Double.doubleToRawLongBits(x));
1868 }
1869
1870 @ForceInline
1871 public final boolean weakCompareAndSetDouble(Object o, long offset,
1872 double expected,
1873 double x) {
1874 return weakCompareAndSetLong(o, offset,
1875 Double.doubleToRawLongBits(expected),
1876 Double.doubleToRawLongBits(x));
1877 }
1878
1879 /**
1880 * Atomically updates Java variable to {@code x} if it is currently
1881 * holding {@code expected}.
1882 *
1883 * <p>This operation has memory semantics of a {@code volatile} read
1884 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1885 *
1886 * @return {@code true} if successful
1887 */
1888 @HotSpotIntrinsicCandidate
1889 public final native boolean compareAndSetLong(Object o, long offset,
1890 long expected,
1891 long x);
1892
1893 @HotSpotIntrinsicCandidate
1894 public final native long compareAndExchangeLong(Object o, long offset,
1895 long expected,
1896 long x);
1897
1898 @HotSpotIntrinsicCandidate
1899 public final long compareAndExchangeLongAcquire(Object o, long offset,
1900 long expected,
1901 long x) {
1902 return compareAndExchangeLong(o, offset, expected, x);
1903 }
1904
1905 @HotSpotIntrinsicCandidate
1906 public final long compareAndExchangeLongRelease(Object o, long offset,
1907 long expected,
1908 long x) {
1909 return compareAndExchangeLong(o, offset, expected, x);
1910 }
1911
1912 @HotSpotIntrinsicCandidate
1913 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
1914 long expected,
1915 long x) {
1916 return compareAndSetLong(o, offset, expected, x);
1917 }
1918
1919 @HotSpotIntrinsicCandidate
1920 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
1921 long expected,
1922 long x) {
1923 return compareAndSetLong(o, offset, expected, x);
1924 }
1925
1926 @HotSpotIntrinsicCandidate
1927 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
1928 long expected,
1929 long x) {
1930 return compareAndSetLong(o, offset, expected, x);
1931 }
1932
1933 @HotSpotIntrinsicCandidate
1934 public final boolean weakCompareAndSetLong(Object o, long offset,
1935 long expected,
1936 long x) {
1937 return compareAndSetLong(o, offset, expected, x);
1938 }
1939
1940 /**
1941 * Fetches a reference value from a given Java variable, with volatile
1942 * load semantics. Otherwise identical to {@link #getObject(Object, long)}
1943 */
1944 @HotSpotIntrinsicCandidate
1945 public native Object getObjectVolatile(Object o, long offset);
1946
1947 /**
1948 * Stores a reference value into a given Java variable, with
1949 * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)}
1950 */
1951 @HotSpotIntrinsicCandidate
1952 public native void putObjectVolatile(Object o, long offset, Object x);
1953
1954 /** Volatile version of {@link #getInt(Object, long)} */
1955 @HotSpotIntrinsicCandidate
1956 public native int getIntVolatile(Object o, long offset);
1957
1958 /** Volatile version of {@link #putInt(Object, long, int)} */
1959 @HotSpotIntrinsicCandidate
1960 public native void putIntVolatile(Object o, long offset, int x);
1961
1962 /** Volatile version of {@link #getBoolean(Object, long)} */
1963 @HotSpotIntrinsicCandidate
1964 public native boolean getBooleanVolatile(Object o, long offset);
1965
1966 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
1967 @HotSpotIntrinsicCandidate
1968 public native void putBooleanVolatile(Object o, long offset, boolean x);
1969
1970 /** Volatile version of {@link #getByte(Object, long)} */
1971 @HotSpotIntrinsicCandidate
1972 public native byte getByteVolatile(Object o, long offset);
1973
1974 /** Volatile version of {@link #putByte(Object, long, byte)} */
1975 @HotSpotIntrinsicCandidate
1976 public native void putByteVolatile(Object o, long offset, byte x);
1977
1978 /** Volatile version of {@link #getShort(Object, long)} */
1979 @HotSpotIntrinsicCandidate
1980 public native short getShortVolatile(Object o, long offset);
1981
1982 /** Volatile version of {@link #putShort(Object, long, short)} */
1983 @HotSpotIntrinsicCandidate
1984 public native void putShortVolatile(Object o, long offset, short x);
1985
1986 /** Volatile version of {@link #getChar(Object, long)} */
1987 @HotSpotIntrinsicCandidate
1988 public native char getCharVolatile(Object o, long offset);
1989
1990 /** Volatile version of {@link #putChar(Object, long, char)} */
1991 @HotSpotIntrinsicCandidate
1992 public native void putCharVolatile(Object o, long offset, char x);
1993
1994 /** Volatile version of {@link #getLong(Object, long)} */
1995 @HotSpotIntrinsicCandidate
1996 public native long getLongVolatile(Object o, long offset);
1997
1998 /** Volatile version of {@link #putLong(Object, long, long)} */
1999 @HotSpotIntrinsicCandidate
2000 public native void putLongVolatile(Object o, long offset, long x);
2001
2002 /** Volatile version of {@link #getFloat(Object, long)} */
2003 @HotSpotIntrinsicCandidate
2004 public native float getFloatVolatile(Object o, long offset);
2005
2006 /** Volatile version of {@link #putFloat(Object, long, float)} */
2007 @HotSpotIntrinsicCandidate
2008 public native void putFloatVolatile(Object o, long offset, float x);
2009
2010 /** Volatile version of {@link #getDouble(Object, long)} */
2011 @HotSpotIntrinsicCandidate
2012 public native double getDoubleVolatile(Object o, long offset);
2013
2014 /** Volatile version of {@link #putDouble(Object, long, double)} */
2015 @HotSpotIntrinsicCandidate
2016 public native void putDoubleVolatile(Object o, long offset, double x);
2017
2018
2019
2020 /** Acquire version of {@link #getObjectVolatile(Object, long)} */
2021 @HotSpotIntrinsicCandidate
2022 public final Object getObjectAcquire(Object o, long offset) {
2023 return getObjectVolatile(o, offset);
2024 }
2025
2026 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2027 @HotSpotIntrinsicCandidate
2028 public final boolean getBooleanAcquire(Object o, long offset) {
2029 return getBooleanVolatile(o, offset);
2030 }
2031
2032 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2033 @HotSpotIntrinsicCandidate
2034 public final byte getByteAcquire(Object o, long offset) {
2035 return getByteVolatile(o, offset);
2036 }
2037
2038 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2039 @HotSpotIntrinsicCandidate
2040 public final short getShortAcquire(Object o, long offset) {
2041 return getShortVolatile(o, offset);
2042 }
2043
2044 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2045 @HotSpotIntrinsicCandidate
2046 public final char getCharAcquire(Object o, long offset) {
2047 return getCharVolatile(o, offset);
2048 }
2049
2050 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2051 @HotSpotIntrinsicCandidate
2052 public final int getIntAcquire(Object o, long offset) {
2053 return getIntVolatile(o, offset);
2054 }
2055
2056 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2057 @HotSpotIntrinsicCandidate
2058 public final float getFloatAcquire(Object o, long offset) {
2059 return getFloatVolatile(o, offset);
2060 }
2061
2062 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2063 @HotSpotIntrinsicCandidate
2064 public final long getLongAcquire(Object o, long offset) {
2065 return getLongVolatile(o, offset);
2066 }
2067
2068 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2069 @HotSpotIntrinsicCandidate
2070 public final double getDoubleAcquire(Object o, long offset) {
2071 return getDoubleVolatile(o, offset);
2072 }
2073
2074 /*
2075 * Versions of {@link #putObjectVolatile(Object, long, Object)}
2076 * that do not guarantee immediate visibility of the store to
2077 * other threads. This method is generally only useful if the
2078 * underlying field is a Java volatile (or if an array cell, one
2079 * that is otherwise only accessed using volatile accesses).
2080 *
2081 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2082 */
2083
2084 /** Release version of {@link #putObjectVolatile(Object, long, Object)} */
2085 @HotSpotIntrinsicCandidate
2086 public final void putObjectRelease(Object o, long offset, Object x) {
2087 putObjectVolatile(o, offset, x);
2088 }
2089
2090 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2091 @HotSpotIntrinsicCandidate
2092 public final void putBooleanRelease(Object o, long offset, boolean x) {
2093 putBooleanVolatile(o, offset, x);
2094 }
2095
2096 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2097 @HotSpotIntrinsicCandidate
2098 public final void putByteRelease(Object o, long offset, byte x) {
2099 putByteVolatile(o, offset, x);
2100 }
2101
2102 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2103 @HotSpotIntrinsicCandidate
2104 public final void putShortRelease(Object o, long offset, short x) {
2105 putShortVolatile(o, offset, x);
2106 }
2107
2108 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2109 @HotSpotIntrinsicCandidate
2110 public final void putCharRelease(Object o, long offset, char x) {
2111 putCharVolatile(o, offset, x);
2112 }
2113
2114 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2115 @HotSpotIntrinsicCandidate
2116 public final void putIntRelease(Object o, long offset, int x) {
2117 putIntVolatile(o, offset, x);
2118 }
2119
2120 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2121 @HotSpotIntrinsicCandidate
2122 public final void putFloatRelease(Object o, long offset, float x) {
2123 putFloatVolatile(o, offset, x);
2124 }
2125
2126 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2127 @HotSpotIntrinsicCandidate
2128 public final void putLongRelease(Object o, long offset, long x) {
2129 putLongVolatile(o, offset, x);
2130 }
2131
2132 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2133 @HotSpotIntrinsicCandidate
2134 public final void putDoubleRelease(Object o, long offset, double x) {
2135 putDoubleVolatile(o, offset, x);
2136 }
2137
2138 // ------------------------------ Opaque --------------------------------------
2139
2140 /** Opaque version of {@link #getObjectVolatile(Object, long)} */
2141 @HotSpotIntrinsicCandidate
2142 public final Object getObjectOpaque(Object o, long offset) {
2143 return getObjectVolatile(o, offset);
2144 }
2145
2146 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2147 @HotSpotIntrinsicCandidate
2148 public final boolean getBooleanOpaque(Object o, long offset) {
2149 return getBooleanVolatile(o, offset);
2150 }
2151
2152 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2153 @HotSpotIntrinsicCandidate
2154 public final byte getByteOpaque(Object o, long offset) {
2155 return getByteVolatile(o, offset);
2156 }
2157
2158 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2159 @HotSpotIntrinsicCandidate
2160 public final short getShortOpaque(Object o, long offset) {
2161 return getShortVolatile(o, offset);
2162 }
2163
2164 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2165 @HotSpotIntrinsicCandidate
2166 public final char getCharOpaque(Object o, long offset) {
2167 return getCharVolatile(o, offset);
2168 }
2169
2170 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2171 @HotSpotIntrinsicCandidate
2172 public final int getIntOpaque(Object o, long offset) {
2173 return getIntVolatile(o, offset);
2174 }
2175
2176 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2177 @HotSpotIntrinsicCandidate
2178 public final float getFloatOpaque(Object o, long offset) {
2179 return getFloatVolatile(o, offset);
2180 }
2181
2182 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2183 @HotSpotIntrinsicCandidate
2184 public final long getLongOpaque(Object o, long offset) {
2185 return getLongVolatile(o, offset);
2186 }
2187
2188 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2189 @HotSpotIntrinsicCandidate
2190 public final double getDoubleOpaque(Object o, long offset) {
2191 return getDoubleVolatile(o, offset);
2192 }
2193
2194 /** Opaque version of {@link #putObjectVolatile(Object, long, Object)} */
2195 @HotSpotIntrinsicCandidate
2196 public final void putObjectOpaque(Object o, long offset, Object x) {
2197 putObjectVolatile(o, offset, x);
2198 }
2199
2200 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2201 @HotSpotIntrinsicCandidate
2202 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2203 putBooleanVolatile(o, offset, x);
2204 }
2205
2206 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2207 @HotSpotIntrinsicCandidate
2208 public final void putByteOpaque(Object o, long offset, byte x) {
2209 putByteVolatile(o, offset, x);
2210 }
2211
2212 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2213 @HotSpotIntrinsicCandidate
2214 public final void putShortOpaque(Object o, long offset, short x) {
2215 putShortVolatile(o, offset, x);
2216 }
2217
2218 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2219 @HotSpotIntrinsicCandidate
2220 public final void putCharOpaque(Object o, long offset, char x) {
2221 putCharVolatile(o, offset, x);
2222 }
2223
2224 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2225 @HotSpotIntrinsicCandidate
2226 public final void putIntOpaque(Object o, long offset, int x) {
2227 putIntVolatile(o, offset, x);
2228 }
2229
2230 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2231 @HotSpotIntrinsicCandidate
2232 public final void putFloatOpaque(Object o, long offset, float x) {
2233 putFloatVolatile(o, offset, x);
2234 }
2235
2236 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2237 @HotSpotIntrinsicCandidate
2238 public final void putLongOpaque(Object o, long offset, long x) {
2239 putLongVolatile(o, offset, x);
2240 }
2241
2242 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2243 @HotSpotIntrinsicCandidate
2244 public final void putDoubleOpaque(Object o, long offset, double x) {
2245 putDoubleVolatile(o, offset, x);
2246 }
2247
2248 /**
2249 * Unblocks the given thread blocked on {@code park}, or, if it is
2250 * not blocked, causes the subsequent call to {@code park} not to
2251 * block. Note: this operation is "unsafe" solely because the
2252 * caller must somehow ensure that the thread has not been
2253 * destroyed. Nothing special is usually required to ensure this
2254 * when called from Java (in which there will ordinarily be a live
2255 * reference to the thread) but this is not nearly-automatically
2256 * so when calling from native code.
2257 *
2258 * @param thread the thread to unpark.
2259 */
2260 @HotSpotIntrinsicCandidate
2261 public native void unpark(Object thread);
2262
2263 /**
2264 * Blocks current thread, returning when a balancing
2265 * {@code unpark} occurs, or a balancing {@code unpark} has
2266 * already occurred, or the thread is interrupted, or, if not
2267 * absolute and time is not zero, the given time nanoseconds have
2268 * elapsed, or if absolute, the given deadline in milliseconds
2269 * since Epoch has passed, or spuriously (i.e., returning for no
2270 * "reason"). Note: This operation is in the Unsafe class only
2271 * because {@code unpark} is, so it would be strange to place it
2272 * elsewhere.
2273 */
2274 @HotSpotIntrinsicCandidate
2275 public native void park(boolean isAbsolute, long time);
2276
2277 /**
2278 * Gets the load average in the system run queue assigned
2279 * to the available processors averaged over various periods of time.
2280 * This method retrieves the given {@code nelem} samples and
2281 * assigns to the elements of the given {@code loadavg} array.
2282 * The system imposes a maximum of 3 samples, representing
2283 * averages over the last 1, 5, and 15 minutes, respectively.
2284 *
2285 * @param loadavg an array of double of size nelems
2286 * @param nelems the number of samples to be retrieved and
2287 * must be 1 to 3.
2288 *
2289 * @return the number of samples actually retrieved; or -1
2290 * if the load average is unobtainable.
2291 */
2292 public int getLoadAverage(double[] loadavg, int nelems) {
2293 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2294 throw new ArrayIndexOutOfBoundsException();
2295 }
2296
2297 return getLoadAverage0(loadavg, nelems);
2298 }
2299
2300 // The following contain CAS-based Java implementations used on
2301 // platforms not supporting native instructions
2302
2303 /**
2304 * Atomically adds the given value to the current value of a field
2305 * or array element within the given object {@code o}
2306 * at the given {@code offset}.
2307 *
2308 * @param o object/array to update the field/element in
2309 * @param offset field/element offset
2310 * @param delta the value to add
2311 * @return the previous value
2312 * @since 1.8
2313 */
2314 @HotSpotIntrinsicCandidate
2315 public final int getAndAddInt(Object o, long offset, int delta) {
2316 int v;
2317 do {
2318 v = getIntVolatile(o, offset);
2319 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
2320 return v;
2321 }
2322
2323 @ForceInline
2324 public final int getAndAddIntRelease(Object o, long offset, int delta) {
2325 int v;
2326 do {
2327 v = getInt(o, offset);
2328 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
2329 return v;
2330 }
2331
2332 @ForceInline
2333 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
2334 int v;
2335 do {
2336 v = getIntAcquire(o, offset);
2337 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
2338 return v;
2339 }
2340
2341 /**
2342 * Atomically adds the given value to the current value of a field
2343 * or array element within the given object {@code o}
2344 * at the given {@code offset}.
2345 *
2346 * @param o object/array to update the field/element in
2347 * @param offset field/element offset
2348 * @param delta the value to add
2349 * @return the previous value
2350 * @since 1.8
2351 */
2352 @HotSpotIntrinsicCandidate
2353 public final long getAndAddLong(Object o, long offset, long delta) {
2354 long v;
2355 do {
2356 v = getLongVolatile(o, offset);
2357 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
2358 return v;
2359 }
2360
2361 @ForceInline
2362 public final long getAndAddLongRelease(Object o, long offset, long delta) {
2363 long v;
2364 do {
2365 v = getLong(o, offset);
2366 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
2367 return v;
2368 }
2369
2370 @ForceInline
2371 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
2372 long v;
2373 do {
2374 v = getLongAcquire(o, offset);
2375 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
2376 return v;
2377 }
2378
2379 @HotSpotIntrinsicCandidate
2380 public final byte getAndAddByte(Object o, long offset, byte delta) {
2381 byte v;
2382 do {
2383 v = getByteVolatile(o, offset);
2384 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
2385 return v;
2386 }
2387
2388 @ForceInline
2389 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
2390 byte v;
2391 do {
2392 v = getByte(o, offset);
2393 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
2394 return v;
2395 }
2396
2397 @ForceInline
2398 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
2399 byte v;
2400 do {
2401 v = getByteAcquire(o, offset);
2402 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
2403 return v;
2404 }
2405
2406 @HotSpotIntrinsicCandidate
2407 public final short getAndAddShort(Object o, long offset, short delta) {
2408 short v;
2409 do {
2410 v = getShortVolatile(o, offset);
2411 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
2412 return v;
2413 }
2414
2415 @ForceInline
2416 public final short getAndAddShortRelease(Object o, long offset, short delta) {
2417 short v;
2418 do {
2419 v = getShort(o, offset);
2420 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
2421 return v;
2422 }
2423
2424 @ForceInline
2425 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
2426 short v;
2427 do {
2428 v = getShortAcquire(o, offset);
2429 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
2430 return v;
2431 }
2432
2433 @ForceInline
2434 public final char getAndAddChar(Object o, long offset, char delta) {
2435 return (char) getAndAddShort(o, offset, (short) delta);
2436 }
2437
2438 @ForceInline
2439 public final char getAndAddCharRelease(Object o, long offset, char delta) {
2440 return (char) getAndAddShortRelease(o, offset, (short) delta);
2441 }
2442
2443 @ForceInline
2444 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
2445 return (char) getAndAddShortAcquire(o, offset, (short) delta);
2446 }
2447
2448 @ForceInline
2449 public final float getAndAddFloat(Object o, long offset, float delta) {
2450 int expectedBits;
2451 float v;
2452 do {
2453 // Load and CAS with the raw bits to avoid issues with NaNs and
2454 // possible bit conversion from signaling NaNs to quiet NaNs that
2455 // may result in the loop not terminating.
2456 expectedBits = getIntVolatile(o, offset);
2457 v = Float.intBitsToFloat(expectedBits);
2458 } while (!weakCompareAndSetInt(o, offset,
2459 expectedBits, Float.floatToRawIntBits(v + delta)));
2460 return v;
2461 }
2462
2463 @ForceInline
2464 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
2465 int expectedBits;
2466 float v;
2467 do {
2468 // Load and CAS with the raw bits to avoid issues with NaNs and
2469 // possible bit conversion from signaling NaNs to quiet NaNs that
2470 // may result in the loop not terminating.
2471 expectedBits = getInt(o, offset);
2472 v = Float.intBitsToFloat(expectedBits);
2473 } while (!weakCompareAndSetIntRelease(o, offset,
2474 expectedBits, Float.floatToRawIntBits(v + delta)));
2475 return v;
2476 }
2477
2478 @ForceInline
2479 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
2480 int expectedBits;
2481 float v;
2482 do {
2483 // Load and CAS with the raw bits to avoid issues with NaNs and
2484 // possible bit conversion from signaling NaNs to quiet NaNs that
2485 // may result in the loop not terminating.
2486 expectedBits = getIntAcquire(o, offset);
2487 v = Float.intBitsToFloat(expectedBits);
2488 } while (!weakCompareAndSetIntAcquire(o, offset,
2489 expectedBits, Float.floatToRawIntBits(v + delta)));
2490 return v;
2491 }
2492
2493 @ForceInline
2494 public final double getAndAddDouble(Object o, long offset, double delta) {
2495 long expectedBits;
2496 double v;
2497 do {
2498 // Load and CAS with the raw bits to avoid issues with NaNs and
2499 // possible bit conversion from signaling NaNs to quiet NaNs that
2500 // may result in the loop not terminating.
2501 expectedBits = getLongVolatile(o, offset);
2502 v = Double.longBitsToDouble(expectedBits);
2503 } while (!weakCompareAndSetLong(o, offset,
2504 expectedBits, Double.doubleToRawLongBits(v + delta)));
2505 return v;
2506 }
2507
2508 @ForceInline
2509 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
2510 long expectedBits;
2511 double v;
2512 do {
2513 // Load and CAS with the raw bits to avoid issues with NaNs and
2514 // possible bit conversion from signaling NaNs to quiet NaNs that
2515 // may result in the loop not terminating.
2516 expectedBits = getLong(o, offset);
2517 v = Double.longBitsToDouble(expectedBits);
2518 } while (!weakCompareAndSetLongRelease(o, offset,
2519 expectedBits, Double.doubleToRawLongBits(v + delta)));
2520 return v;
2521 }
2522
2523 @ForceInline
2524 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
2525 long expectedBits;
2526 double v;
2527 do {
2528 // Load and CAS with the raw bits to avoid issues with NaNs and
2529 // possible bit conversion from signaling NaNs to quiet NaNs that
2530 // may result in the loop not terminating.
2531 expectedBits = getLongAcquire(o, offset);
2532 v = Double.longBitsToDouble(expectedBits);
2533 } while (!weakCompareAndSetLongAcquire(o, offset,
2534 expectedBits, Double.doubleToRawLongBits(v + delta)));
2535 return v;
2536 }
2537
2538 /**
2539 * Atomically exchanges the given value with the current value of
2540 * a field or array element within the given object {@code o}
2541 * at the given {@code offset}.
2542 *
2543 * @param o object/array to update the field/element in
2544 * @param offset field/element offset
2545 * @param newValue new value
2546 * @return the previous value
2547 * @since 1.8
2548 */
2549 @HotSpotIntrinsicCandidate
2550 public final int getAndSetInt(Object o, long offset, int newValue) {
2551 int v;
2552 do {
2553 v = getIntVolatile(o, offset);
2554 } while (!weakCompareAndSetInt(o, offset, v, newValue));
2555 return v;
2556 }
2557
2558 @ForceInline
2559 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
2560 int v;
2561 do {
2562 v = getInt(o, offset);
2563 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
2564 return v;
2565 }
2566
2567 @ForceInline
2568 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
2569 int v;
2570 do {
2571 v = getIntAcquire(o, offset);
2572 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
2573 return v;
2574 }
2575
2576 /**
2577 * Atomically exchanges the given value with the current value of
2578 * a field or array element within the given object {@code o}
2579 * at the given {@code offset}.
2580 *
2581 * @param o object/array to update the field/element in
2582 * @param offset field/element offset
2583 * @param newValue new value
2584 * @return the previous value
2585 * @since 1.8
2586 */
2587 @HotSpotIntrinsicCandidate
2588 public final long getAndSetLong(Object o, long offset, long newValue) {
2589 long v;
2590 do {
2591 v = getLongVolatile(o, offset);
2592 } while (!weakCompareAndSetLong(o, offset, v, newValue));
2593 return v;
2594 }
2595
2596 @ForceInline
2597 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
2598 long v;
2599 do {
2600 v = getLong(o, offset);
2601 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
2602 return v;
2603 }
2604
2605 @ForceInline
2606 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
2607 long v;
2608 do {
2609 v = getLongAcquire(o, offset);
2610 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
2611 return v;
2612 }
2613
2614 /**
2615 * Atomically exchanges the given reference value with the current
2616 * reference value of a field or array element within the given
2617 * object {@code o} at the given {@code offset}.
2618 *
2619 * @param o object/array to update the field/element in
2620 * @param offset field/element offset
2621 * @param newValue new value
2622 * @return the previous value
2623 * @since 1.8
2624 */
2625 @HotSpotIntrinsicCandidate
2626 public final Object getAndSetObject(Object o, long offset, Object newValue) {
2627 Object v;
2628 do {
2629 v = getObjectVolatile(o, offset);
2630 } while (!weakCompareAndSetObject(o, offset, v, newValue));
2631 return v;
2632 }
2633
2634 @ForceInline
2635 public final Object getAndSetObjectRelease(Object o, long offset, Object newValue) {
2636 Object v;
2637 do {
2638 v = getObject(o, offset);
2639 } while (!weakCompareAndSetObjectRelease(o, offset, v, newValue));
2640 return v;
2641 }
2642
2643 @ForceInline
2644 public final Object getAndSetObjectAcquire(Object o, long offset, Object newValue) {
2645 Object v;
2646 do {
2647 v = getObjectAcquire(o, offset);
2648 } while (!weakCompareAndSetObjectAcquire(o, offset, v, newValue));
2649 return v;
2650 }
2651
2652 @HotSpotIntrinsicCandidate
2653 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2654 byte v;
2655 do {
2656 v = getByteVolatile(o, offset);
2657 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2658 return v;
2659 }
2660
2661 @ForceInline
2662 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2663 byte v;
2664 do {
2665 v = getByte(o, offset);
2666 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2667 return v;
2668 }
2669
2670 @ForceInline
2671 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
2672 byte v;
2673 do {
2674 v = getByteAcquire(o, offset);
2675 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
2676 return v;
2677 }
2678
2679 @ForceInline
2680 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
2681 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
2682 }
2683
2684 @ForceInline
2685 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
2686 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
2687 }
2688
2689 @ForceInline
2690 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
2691 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
2692 }
2693
2694 @HotSpotIntrinsicCandidate
2695 public final short getAndSetShort(Object o, long offset, short newValue) {
2696 short v;
2697 do {
2698 v = getShortVolatile(o, offset);
2699 } while (!weakCompareAndSetShort(o, offset, v, newValue));
2700 return v;
2701 }
2702
2703 @ForceInline
2704 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
2705 short v;
2706 do {
2707 v = getShort(o, offset);
2708 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
2709 return v;
2710 }
2711
2712 @ForceInline
2713 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
2714 short v;
2715 do {
2716 v = getShortAcquire(o, offset);
2717 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
2718 return v;
2719 }
2720
2721 @ForceInline
2722 public final char getAndSetChar(Object o, long offset, char newValue) {
2723 return s2c(getAndSetShort(o, offset, c2s(newValue)));
2724 }
2725
2726 @ForceInline
2727 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
2728 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
2729 }
2730
2731 @ForceInline
2732 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
2733 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
2734 }
2735
2736 @ForceInline
2737 public final float getAndSetFloat(Object o, long offset, float newValue) {
2738 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
2739 return Float.intBitsToFloat(v);
2740 }
2741
2742 @ForceInline
2743 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
2744 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
2745 return Float.intBitsToFloat(v);
2746 }
2747
2748 @ForceInline
2749 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
2750 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
2751 return Float.intBitsToFloat(v);
2752 }
2753
2754 @ForceInline
2755 public final double getAndSetDouble(Object o, long offset, double newValue) {
2756 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
2757 return Double.longBitsToDouble(v);
2758 }
2759
2760 @ForceInline
2761 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
2762 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
2763 return Double.longBitsToDouble(v);
2764 }
2765
2766 @ForceInline
2767 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
2768 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
2769 return Double.longBitsToDouble(v);
2770 }
2771
2772
2773 // The following contain CAS-based Java implementations used on
2774 // platforms not supporting native instructions
2775
2776 @ForceInline
2777 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
2778 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
2779 }
2780
2781 @ForceInline
2782 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
2783 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
2784 }
2785
2786 @ForceInline
2787 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
2788 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
2789 }
2790
2791 @ForceInline
2792 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
2793 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
2794 }
2795
2796 @ForceInline
2797 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
2798 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
2799 }
2800
2801 @ForceInline
2802 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
2803 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
2804 }
2805
2806 @ForceInline
2807 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
2808 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
2809 }
2810
2811 @ForceInline
2812 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
2813 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
2814 }
2815
2816 @ForceInline
2817 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
2818 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
2819 }
2820
2821
2822 @ForceInline
2823 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
2824 byte current;
2825 do {
2826 current = getByteVolatile(o, offset);
2827 } while (!weakCompareAndSetByte(o, offset,
2828 current, (byte) (current | mask)));
2829 return current;
2830 }
2831
2832 @ForceInline
2833 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
2834 byte current;
2835 do {
2836 current = getByte(o, offset);
2837 } while (!weakCompareAndSetByteRelease(o, offset,
2838 current, (byte) (current | mask)));
2839 return current;
2840 }
2841
2842 @ForceInline
2843 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
2844 byte current;
2845 do {
2846 // Plain read, the value is a hint, the acquire CAS does the work
2847 current = getByte(o, offset);
2848 } while (!weakCompareAndSetByteAcquire(o, offset,
2849 current, (byte) (current | mask)));
2850 return current;
2851 }
2852
2853 @ForceInline
2854 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
2855 byte current;
2856 do {
2857 current = getByteVolatile(o, offset);
2858 } while (!weakCompareAndSetByte(o, offset,
2859 current, (byte) (current & mask)));
2860 return current;
2861 }
2862
2863 @ForceInline
2864 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
2865 byte current;
2866 do {
2867 current = getByte(o, offset);
2868 } while (!weakCompareAndSetByteRelease(o, offset,
2869 current, (byte) (current & mask)));
2870 return current;
2871 }
2872
2873 @ForceInline
2874 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
2875 byte current;
2876 do {
2877 // Plain read, the value is a hint, the acquire CAS does the work
2878 current = getByte(o, offset);
2879 } while (!weakCompareAndSetByteAcquire(o, offset,
2880 current, (byte) (current & mask)));
2881 return current;
2882 }
2883
2884 @ForceInline
2885 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
2886 byte current;
2887 do {
2888 current = getByteVolatile(o, offset);
2889 } while (!weakCompareAndSetByte(o, offset,
2890 current, (byte) (current ^ mask)));
2891 return current;
2892 }
2893
2894 @ForceInline
2895 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
2896 byte current;
2897 do {
2898 current = getByte(o, offset);
2899 } while (!weakCompareAndSetByteRelease(o, offset,
2900 current, (byte) (current ^ mask)));
2901 return current;
2902 }
2903
2904 @ForceInline
2905 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
2906 byte current;
2907 do {
2908 // Plain read, the value is a hint, the acquire CAS does the work
2909 current = getByte(o, offset);
2910 } while (!weakCompareAndSetByteAcquire(o, offset,
2911 current, (byte) (current ^ mask)));
2912 return current;
2913 }
2914
2915
2916 @ForceInline
2917 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
2918 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
2919 }
2920
2921 @ForceInline
2922 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
2923 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
2924 }
2925
2926 @ForceInline
2927 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
2928 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
2929 }
2930
2931 @ForceInline
2932 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
2933 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
2934 }
2935
2936 @ForceInline
2937 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
2938 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
2939 }
2940
2941 @ForceInline
2942 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
2943 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
2944 }
2945
2946 @ForceInline
2947 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
2948 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
2949 }
2950
2951 @ForceInline
2952 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
2953 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
2954 }
2955
2956 @ForceInline
2957 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
2958 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
2959 }
2960
2961
2962 @ForceInline
2963 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
2964 short current;
2965 do {
2966 current = getShortVolatile(o, offset);
2967 } while (!weakCompareAndSetShort(o, offset,
2968 current, (short) (current | mask)));
2969 return current;
2970 }
2971
2972 @ForceInline
2973 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
2974 short current;
2975 do {
2976 current = getShort(o, offset);
2977 } while (!weakCompareAndSetShortRelease(o, offset,
2978 current, (short) (current | mask)));
2979 return current;
2980 }
2981
2982 @ForceInline
2983 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
2984 short current;
2985 do {
2986 // Plain read, the value is a hint, the acquire CAS does the work
2987 current = getShort(o, offset);
2988 } while (!weakCompareAndSetShortAcquire(o, offset,
2989 current, (short) (current | mask)));
2990 return current;
2991 }
2992
2993 @ForceInline
2994 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
2995 short current;
2996 do {
2997 current = getShortVolatile(o, offset);
2998 } while (!weakCompareAndSetShort(o, offset,
2999 current, (short) (current & mask)));
3000 return current;
3001 }
3002
3003 @ForceInline
3004 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3005 short current;
3006 do {
3007 current = getShort(o, offset);
3008 } while (!weakCompareAndSetShortRelease(o, offset,
3009 current, (short) (current & mask)));
3010 return current;
3011 }
3012
3013 @ForceInline
3014 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3015 short current;
3016 do {
3017 // Plain read, the value is a hint, the acquire CAS does the work
3018 current = getShort(o, offset);
3019 } while (!weakCompareAndSetShortAcquire(o, offset,
3020 current, (short) (current & mask)));
3021 return current;
3022 }
3023
3024 @ForceInline
3025 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3026 short current;
3027 do {
3028 current = getShortVolatile(o, offset);
3029 } while (!weakCompareAndSetShort(o, offset,
3030 current, (short) (current ^ mask)));
3031 return current;
3032 }
3033
3034 @ForceInline
3035 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3036 short current;
3037 do {
3038 current = getShort(o, offset);
3039 } while (!weakCompareAndSetShortRelease(o, offset,
3040 current, (short) (current ^ mask)));
3041 return current;
3042 }
3043
3044 @ForceInline
3045 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3046 short current;
3047 do {
3048 // Plain read, the value is a hint, the acquire CAS does the work
3049 current = getShort(o, offset);
3050 } while (!weakCompareAndSetShortAcquire(o, offset,
3051 current, (short) (current ^ mask)));
3052 return current;
3053 }
3054
3055
3056 @ForceInline
3057 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3058 int current;
3059 do {
3060 current = getIntVolatile(o, offset);
3061 } while (!weakCompareAndSetInt(o, offset,
3062 current, current | mask));
3063 return current;
3064 }
3065
3066 @ForceInline
3067 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3068 int current;
3069 do {
3070 current = getInt(o, offset);
3071 } while (!weakCompareAndSetIntRelease(o, offset,
3072 current, current | mask));
3073 return current;
3074 }
3075
3076 @ForceInline
3077 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3078 int current;
3079 do {
3080 // Plain read, the value is a hint, the acquire CAS does the work
3081 current = getInt(o, offset);
3082 } while (!weakCompareAndSetIntAcquire(o, offset,
3083 current, current | mask));
3084 return current;
3085 }
3086
3087 /**
3088 * Atomically replaces the current value of a field or array element within
3089 * the given object with the result of bitwise AND between the current value
3090 * and mask.
3091 *
3092 * @param o object/array to update the field/element in
3093 * @param offset field/element offset
3094 * @param mask the mask value
3095 * @return the previous value
3096 * @since 1.9
3097 */
3098 @ForceInline
3099 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3100 int current;
3101 do {
3102 current = getIntVolatile(o, offset);
3103 } while (!weakCompareAndSetInt(o, offset,
3104 current, current & mask));
3105 return current;
3106 }
3107
3108 @ForceInline
3109 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3110 int current;
3111 do {
3112 current = getInt(o, offset);
3113 } while (!weakCompareAndSetIntRelease(o, offset,
3114 current, current & mask));
3115 return current;
3116 }
3117
3118 @ForceInline
3119 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3120 int current;
3121 do {
3122 // Plain read, the value is a hint, the acquire CAS does the work
3123 current = getInt(o, offset);
3124 } while (!weakCompareAndSetIntAcquire(o, offset,
3125 current, current & mask));
3126 return current;
3127 }
3128
3129 @ForceInline
3130 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3131 int current;
3132 do {
3133 current = getIntVolatile(o, offset);
3134 } while (!weakCompareAndSetInt(o, offset,
3135 current, current ^ mask));
3136 return current;
3137 }
3138
3139 @ForceInline
3140 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3141 int current;
3142 do {
3143 current = getInt(o, offset);
3144 } while (!weakCompareAndSetIntRelease(o, offset,
3145 current, current ^ mask));
3146 return current;
3147 }
3148
3149 @ForceInline
3150 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3151 int current;
3152 do {
3153 // Plain read, the value is a hint, the acquire CAS does the work
3154 current = getInt(o, offset);
3155 } while (!weakCompareAndSetIntAcquire(o, offset,
3156 current, current ^ mask));
3157 return current;
3158 }
3159
3160
3161 @ForceInline
3162 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3163 long current;
3164 do {
3165 current = getLongVolatile(o, offset);
3166 } while (!weakCompareAndSetLong(o, offset,
3167 current, current | mask));
3168 return current;
3169 }
3170
3171 @ForceInline
3172 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3173 long current;
3174 do {
3175 current = getLong(o, offset);
3176 } while (!weakCompareAndSetLongRelease(o, offset,
3177 current, current | mask));
3178 return current;
3179 }
3180
3181 @ForceInline
3182 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3183 long current;
3184 do {
3185 // Plain read, the value is a hint, the acquire CAS does the work
3186 current = getLong(o, offset);
3187 } while (!weakCompareAndSetLongAcquire(o, offset,
3188 current, current | mask));
3189 return current;
3190 }
3191
3192 @ForceInline
3193 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3194 long current;
3195 do {
3196 current = getLongVolatile(o, offset);
3197 } while (!weakCompareAndSetLong(o, offset,
3198 current, current & mask));
3199 return current;
3200 }
3201
3202 @ForceInline
3203 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3204 long current;
3205 do {
3206 current = getLong(o, offset);
3207 } while (!weakCompareAndSetLongRelease(o, offset,
3208 current, current & mask));
3209 return current;
3210 }
3211
3212 @ForceInline
3213 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3214 long current;
3215 do {
3216 // Plain read, the value is a hint, the acquire CAS does the work
3217 current = getLong(o, offset);
3218 } while (!weakCompareAndSetLongAcquire(o, offset,
3219 current, current & mask));
3220 return current;
3221 }
3222
3223 @ForceInline
3224 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3225 long current;
3226 do {
3227 current = getLongVolatile(o, offset);
3228 } while (!weakCompareAndSetLong(o, offset,
3229 current, current ^ mask));
3230 return current;
3231 }
3232
3233 @ForceInline
3234 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3235 long current;
3236 do {
3237 current = getLong(o, offset);
3238 } while (!weakCompareAndSetLongRelease(o, offset,
3239 current, current ^ mask));
3240 return current;
3241 }
3242
3243 @ForceInline
3244 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3245 long current;
3246 do {
3247 // Plain read, the value is a hint, the acquire CAS does the work
3248 current = getLong(o, offset);
3249 } while (!weakCompareAndSetLongAcquire(o, offset,
3250 current, current ^ mask));
3251 return current;
3252 }
3253
3254
3255
3256 /**
3257 * Ensures that loads before the fence will not be reordered with loads and
3258 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3259 *
3260 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3261 * (an "acquire fence").
3262 *
3263 * A pure LoadLoad fence is not provided, since the addition of LoadStore
3264 * is almost always desired, and most current hardware instructions that
3265 * provide a LoadLoad barrier also provide a LoadStore barrier for free.
3266 * @since 1.8
3267 */
3268 @HotSpotIntrinsicCandidate
3269 public native void loadFence();
3270
3271 /**
3272 * Ensures that loads and stores before the fence will not be reordered with
3273 * stores after the fence; a "StoreStore plus LoadStore barrier".
3274 *
3275 * Corresponds to C11 atomic_thread_fence(memory_order_release)
3276 * (a "release fence").
3277 *
3278 * A pure StoreStore fence is not provided, since the addition of LoadStore
3279 * is almost always desired, and most current hardware instructions that
3280 * provide a StoreStore barrier also provide a LoadStore barrier for free.
3281 * @since 1.8
3282 */
3283 @HotSpotIntrinsicCandidate
3284 public native void storeFence();
3285
3286 /**
3287 * Ensures that loads and stores before the fence will not be reordered
3288 * with loads and stores after the fence. Implies the effects of both
3289 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
3290 * barrier.
3291 *
3292 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
3293 * @since 1.8
3294 */
3295 @HotSpotIntrinsicCandidate
3296 public native void fullFence();
3297
3298 /**
3299 * Ensures that loads before the fence will not be reordered with
3300 * loads after the fence.
3301 */
3302 public final void loadLoadFence() {
3303 loadFence();
3304 }
3305
3306 /**
3307 * Ensures that stores before the fence will not be reordered with
3308 * stores after the fence.
3309 */
3310 public final void storeStoreFence() {
3311 storeFence();
3312 }
3313
3314
3315 /**
3316 * Throws IllegalAccessError; for use by the VM for access control
3317 * error support.
3318 * @since 1.8
3319 */
3320 private static void throwIllegalAccessError() {
3321 throw new IllegalAccessError();
3322 }
3323
3324 /**
3325 * @return Returns true if the native byte ordering of this
3326 * platform is big-endian, false if it is little-endian.
3327 */
3328 public final boolean isBigEndian() { return BE; }
3329
3330 /**
3331 * @return Returns true if this platform is capable of performing
3332 * accesses at addresses which are not aligned for the type of the
3333 * primitive type being accessed, false otherwise.
3334 */
3335 public final boolean unalignedAccess() { return unalignedAccess; }
3336
3337 /**
3338 * Fetches a value at some byte offset into a given Java object.
3339 * More specifically, fetches a value within the given object
3340 * <code>o</code> at the given offset, or (if <code>o</code> is
3341 * null) from the memory address whose numerical value is the
3342 * given offset. <p>
3343 *
3344 * The specification of this method is the same as {@link
3345 * #getLong(Object, long)} except that the offset does not need to
3346 * have been obtained from {@link #objectFieldOffset} on the
3347 * {@link java.lang.reflect.Field} of some Java field. The value
3348 * in memory is raw data, and need not correspond to any Java
3349 * variable. Unless <code>o</code> is null, the value accessed
3350 * must be entirely within the allocated object. The endianness
3351 * of the value in memory is the endianness of the native platform.
3352 *
3353 * <p> The read will be atomic with respect to the largest power
3354 * of two that divides the GCD of the offset and the storage size.
3355 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
3356 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3357 * respectively. There are no other guarantees of atomicity.
3358 * <p>
3359 * 8-byte atomicity is only guaranteed on platforms on which
3360 * support atomic accesses to longs.
3361 *
3362 * @param o Java heap object in which the value resides, if any, else
3363 * null
3364 * @param offset The offset in bytes from the start of the object
3365 * @return the value fetched from the indicated object
3366 * @throws RuntimeException No defined exceptions are thrown, not even
3367 * {@link NullPointerException}
3368 * @since 9
3369 */
3370 @HotSpotIntrinsicCandidate
3371 public final long getLongUnaligned(Object o, long offset) {
3372 if ((offset & 7) == 0) {
3373 return getLong(o, offset);
3374 } else if ((offset & 3) == 0) {
3375 return makeLong(getInt(o, offset),
3376 getInt(o, offset + 4));
3377 } else if ((offset & 1) == 0) {
3378 return makeLong(getShort(o, offset),
3379 getShort(o, offset + 2),
3380 getShort(o, offset + 4),
3381 getShort(o, offset + 6));
3382 } else {
3383 return makeLong(getByte(o, offset),
3384 getByte(o, offset + 1),
3385 getByte(o, offset + 2),
3386 getByte(o, offset + 3),
3387 getByte(o, offset + 4),
3388 getByte(o, offset + 5),
3389 getByte(o, offset + 6),
3390 getByte(o, offset + 7));
3391 }
3392 }
3393 /**
3394 * As {@link #getLongUnaligned(Object, long)} but with an
3395 * additional argument which specifies the endianness of the value
3396 * as stored in memory.
3397 *
3398 * @param o Java heap object in which the variable resides
3399 * @param offset The offset in bytes from the start of the object
3400 * @param bigEndian The endianness of the value
3401 * @return the value fetched from the indicated object
3402 * @since 9
3403 */
3404 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
3405 return convEndian(bigEndian, getLongUnaligned(o, offset));
3406 }
3407
3408 /** @see #getLongUnaligned(Object, long) */
3409 @HotSpotIntrinsicCandidate
3410 public final int getIntUnaligned(Object o, long offset) {
3411 if ((offset & 3) == 0) {
3412 return getInt(o, offset);
3413 } else if ((offset & 1) == 0) {
3414 return makeInt(getShort(o, offset),
3415 getShort(o, offset + 2));
3416 } else {
3417 return makeInt(getByte(o, offset),
3418 getByte(o, offset + 1),
3419 getByte(o, offset + 2),
3420 getByte(o, offset + 3));
3421 }
3422 }
3423 /** @see #getLongUnaligned(Object, long, boolean) */
3424 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
3425 return convEndian(bigEndian, getIntUnaligned(o, offset));
3426 }
3427
3428 /** @see #getLongUnaligned(Object, long) */
3429 @HotSpotIntrinsicCandidate
3430 public final short getShortUnaligned(Object o, long offset) {
3431 if ((offset & 1) == 0) {
3432 return getShort(o, offset);
3433 } else {
3434 return makeShort(getByte(o, offset),
3435 getByte(o, offset + 1));
3436 }
3437 }
3438 /** @see #getLongUnaligned(Object, long, boolean) */
3439 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
3440 return convEndian(bigEndian, getShortUnaligned(o, offset));
3441 }
3442
3443 /** @see #getLongUnaligned(Object, long) */
3444 @HotSpotIntrinsicCandidate
3445 public final char getCharUnaligned(Object o, long offset) {
3446 if ((offset & 1) == 0) {
3447 return getChar(o, offset);
3448 } else {
3449 return (char)makeShort(getByte(o, offset),
3450 getByte(o, offset + 1));
3451 }
3452 }
3453
3454 /** @see #getLongUnaligned(Object, long, boolean) */
3455 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
3456 return convEndian(bigEndian, getCharUnaligned(o, offset));
3457 }
3458
3459 /**
3460 * Stores a value at some byte offset into a given Java object.
3461 * <p>
3462 * The specification of this method is the same as {@link
3463 * #getLong(Object, long)} except that the offset does not need to
3464 * have been obtained from {@link #objectFieldOffset} on the
3465 * {@link java.lang.reflect.Field} of some Java field. The value
3466 * in memory is raw data, and need not correspond to any Java
3467 * variable. The endianness of the value in memory is the
3468 * endianness of the native platform.
3469 * <p>
3470 * The write will be atomic with respect to the largest power of
3471 * two that divides the GCD of the offset and the storage size.
3472 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
3473 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
3474 * respectively. There are no other guarantees of atomicity.
3475 * <p>
3476 * 8-byte atomicity is only guaranteed on platforms on which
3477 * support atomic accesses to longs.
3478 *
3479 * @param o Java heap object in which the value resides, if any, else
3480 * null
3481 * @param offset The offset in bytes from the start of the object
3482 * @param x the value to store
3483 * @throws RuntimeException No defined exceptions are thrown, not even
3484 * {@link NullPointerException}
3485 * @since 9
3486 */
3487 @HotSpotIntrinsicCandidate
3488 public final void putLongUnaligned(Object o, long offset, long x) {
3489 if ((offset & 7) == 0) {
3490 putLong(o, offset, x);
3491 } else if ((offset & 3) == 0) {
3492 putLongParts(o, offset,
3493 (int)(x >> 0),
3494 (int)(x >>> 32));
3495 } else if ((offset & 1) == 0) {
3496 putLongParts(o, offset,
3497 (short)(x >>> 0),
3498 (short)(x >>> 16),
3499 (short)(x >>> 32),
3500 (short)(x >>> 48));
3501 } else {
3502 putLongParts(o, offset,
3503 (byte)(x >>> 0),
3504 (byte)(x >>> 8),
3505 (byte)(x >>> 16),
3506 (byte)(x >>> 24),
3507 (byte)(x >>> 32),
3508 (byte)(x >>> 40),
3509 (byte)(x >>> 48),
3510 (byte)(x >>> 56));
3511 }
3512 }
3513
3514 /**
3515 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
3516 * argument which specifies the endianness of the value as stored in memory.
3517 * @param o Java heap object in which the value resides
3518 * @param offset The offset in bytes from the start of the object
3519 * @param x the value to store
3520 * @param bigEndian The endianness of the value
3521 * @throws RuntimeException No defined exceptions are thrown, not even
3522 * {@link NullPointerException}
3523 * @since 9
3524 */
3525 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
3526 putLongUnaligned(o, offset, convEndian(bigEndian, x));
3527 }
3528
3529 /** @see #putLongUnaligned(Object, long, long) */
3530 @HotSpotIntrinsicCandidate
3531 public final void putIntUnaligned(Object o, long offset, int x) {
3532 if ((offset & 3) == 0) {
3533 putInt(o, offset, x);
3534 } else if ((offset & 1) == 0) {
3535 putIntParts(o, offset,
3536 (short)(x >> 0),
3537 (short)(x >>> 16));
3538 } else {
3539 putIntParts(o, offset,
3540 (byte)(x >>> 0),
3541 (byte)(x >>> 8),
3542 (byte)(x >>> 16),
3543 (byte)(x >>> 24));
3544 }
3545 }
3546 /** @see #putLongUnaligned(Object, long, long, boolean) */
3547 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
3548 putIntUnaligned(o, offset, convEndian(bigEndian, x));
3549 }
3550
3551 /** @see #putLongUnaligned(Object, long, long) */
3552 @HotSpotIntrinsicCandidate
3553 public final void putShortUnaligned(Object o, long offset, short x) {
3554 if ((offset & 1) == 0) {
3555 putShort(o, offset, x);
3556 } else {
3557 putShortParts(o, offset,
3558 (byte)(x >>> 0),
3559 (byte)(x >>> 8));
3560 }
3561 }
3562 /** @see #putLongUnaligned(Object, long, long, boolean) */
3563 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
3564 putShortUnaligned(o, offset, convEndian(bigEndian, x));
3565 }
3566
3567 /** @see #putLongUnaligned(Object, long, long) */
3568 @HotSpotIntrinsicCandidate
3569 public final void putCharUnaligned(Object o, long offset, char x) {
3570 putShortUnaligned(o, offset, (short)x);
3571 }
3572 /** @see #putLongUnaligned(Object, long, long, boolean) */
3573 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
3574 putCharUnaligned(o, offset, convEndian(bigEndian, x));
3575 }
3576
3577 // JVM interface methods
3578 // BE is true iff the native endianness of this platform is big.
3579 private static final boolean BE = theUnsafe.isBigEndian0();
3580
3581 // unalignedAccess is true iff this platform can perform unaligned accesses.
3582 private static final boolean unalignedAccess = theUnsafe.unalignedAccess0();
3583
3584 private static int pickPos(int top, int pos) { return BE ? top - pos : pos; }
3585
3586 // These methods construct integers from bytes. The byte ordering
3587 // is the native endianness of this platform.
3588 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3589 return ((toUnsignedLong(i0) << pickPos(56, 0))
3590 | (toUnsignedLong(i1) << pickPos(56, 8))
3591 | (toUnsignedLong(i2) << pickPos(56, 16))
3592 | (toUnsignedLong(i3) << pickPos(56, 24))
3593 | (toUnsignedLong(i4) << pickPos(56, 32))
3594 | (toUnsignedLong(i5) << pickPos(56, 40))
3595 | (toUnsignedLong(i6) << pickPos(56, 48))
3596 | (toUnsignedLong(i7) << pickPos(56, 56)));
3597 }
3598 private static long makeLong(short i0, short i1, short i2, short i3) {
3599 return ((toUnsignedLong(i0) << pickPos(48, 0))
3600 | (toUnsignedLong(i1) << pickPos(48, 16))
3601 | (toUnsignedLong(i2) << pickPos(48, 32))
3602 | (toUnsignedLong(i3) << pickPos(48, 48)));
3603 }
3604 private static long makeLong(int i0, int i1) {
3605 return (toUnsignedLong(i0) << pickPos(32, 0))
3606 | (toUnsignedLong(i1) << pickPos(32, 32));
3607 }
3608 private static int makeInt(short i0, short i1) {
3609 return (toUnsignedInt(i0) << pickPos(16, 0))
3610 | (toUnsignedInt(i1) << pickPos(16, 16));
3611 }
3612 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
3613 return ((toUnsignedInt(i0) << pickPos(24, 0))
3614 | (toUnsignedInt(i1) << pickPos(24, 8))
3615 | (toUnsignedInt(i2) << pickPos(24, 16))
3616 | (toUnsignedInt(i3) << pickPos(24, 24)));
3617 }
3618 private static short makeShort(byte i0, byte i1) {
3619 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
3620 | (toUnsignedInt(i1) << pickPos(8, 8)));
3621 }
3622
3623 private static byte pick(byte le, byte be) { return BE ? be : le; }
3624 private static short pick(short le, short be) { return BE ? be : le; }
3625 private static int pick(int le, int be) { return BE ? be : le; }
3626
3627 // These methods write integers to memory from smaller parts
3628 // provided by their caller. The ordering in which these parts
3629 // are written is the native endianness of this platform.
3630 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
3631 putByte(o, offset + 0, pick(i0, i7));
3632 putByte(o, offset + 1, pick(i1, i6));
3633 putByte(o, offset + 2, pick(i2, i5));
3634 putByte(o, offset + 3, pick(i3, i4));
3635 putByte(o, offset + 4, pick(i4, i3));
3636 putByte(o, offset + 5, pick(i5, i2));
3637 putByte(o, offset + 6, pick(i6, i1));
3638 putByte(o, offset + 7, pick(i7, i0));
3639 }
3640 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
3641 putShort(o, offset + 0, pick(i0, i3));
3642 putShort(o, offset + 2, pick(i1, i2));
3643 putShort(o, offset + 4, pick(i2, i1));
3644 putShort(o, offset + 6, pick(i3, i0));
3645 }
3646 private void putLongParts(Object o, long offset, int i0, int i1) {
3647 putInt(o, offset + 0, pick(i0, i1));
3648 putInt(o, offset + 4, pick(i1, i0));
3649 }
3650 private void putIntParts(Object o, long offset, short i0, short i1) {
3651 putShort(o, offset + 0, pick(i0, i1));
3652 putShort(o, offset + 2, pick(i1, i0));
3653 }
3654 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
3655 putByte(o, offset + 0, pick(i0, i3));
3656 putByte(o, offset + 1, pick(i1, i2));
3657 putByte(o, offset + 2, pick(i2, i1));
3658 putByte(o, offset + 3, pick(i3, i0));
3659 }
3660 private void putShortParts(Object o, long offset, byte i0, byte i1) {
3661 putByte(o, offset + 0, pick(i0, i1));
3662 putByte(o, offset + 1, pick(i1, i0));
3663 }
3664
3665 // Zero-extend an integer
3666 private static int toUnsignedInt(byte n) { return n & 0xff; }
3667 private static int toUnsignedInt(short n) { return n & 0xffff; }
3668 private static long toUnsignedLong(byte n) { return n & 0xffl; }
3669 private static long toUnsignedLong(short n) { return n & 0xffffl; }
3670 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
3671
3672 // Maybe byte-reverse an integer
3673 private static char convEndian(boolean big, char n) { return big == BE ? n : Character.reverseBytes(n); }
3674 private static short convEndian(boolean big, short n) { return big == BE ? n : Short.reverseBytes(n) ; }
3675 private static int convEndian(boolean big, int n) { return big == BE ? n : Integer.reverseBytes(n) ; }
3676 private static long convEndian(boolean big, long n) { return big == BE ? n : Long.reverseBytes(n) ; }
3677
3678
3679
3680 private native long allocateMemory0(long bytes);
3681 private native long reallocateMemory0(long address, long bytes);
3682 private native void freeMemory0(long address);
3683 private native void setMemory0(Object o, long offset, long bytes, byte value);
3684 @HotSpotIntrinsicCandidate
3685 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3686 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3687 private native long objectFieldOffset0(Field f);
3688 private native long staticFieldOffset0(Field f);
3689 private native Object staticFieldBase0(Field f);
3690 private native boolean shouldBeInitialized0(Class<?> c);
3691 private native void ensureClassInitialized0(Class<?> c);
3692 private native int arrayBaseOffset0(Class<?> arrayClass);
3693 private native int arrayIndexScale0(Class<?> arrayClass);
3694 private native int addressSize0();
3695 private native Class<?> defineAnonymousClass0(Class<?> hostClass, byte[] data, Object[] cpPatches);
3696 private native int getLoadAverage0(double[] loadavg, int nelems);
3697 private native boolean unalignedAccess0();
3698 private native boolean isBigEndian0();
3699 }