1 /*
2 * Copyright (c) 2000, 2025, 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.value.ValueClass;
29 import jdk.internal.vm.annotation.AOTRuntimeSetup;
30 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
31 import jdk.internal.vm.annotation.ForceInline;
32 import jdk.internal.vm.annotation.IntrinsicCandidate;
33 import sun.nio.Cleaner;
34 import sun.nio.ch.DirectBuffer;
35
36 import java.lang.reflect.Field;
37 import java.security.ProtectionDomain;
38
39 import static jdk.internal.misc.UnsafeConstants.*;
40
41 /**
42 * A collection of methods for performing low-level, unsafe operations.
43 * Although the class and all methods are public, use of this class is
44 * limited because only trusted code can obtain instances of it.
45 *
46 * <em>Note:</em> It is the responsibility of the caller to make sure
47 * arguments are checked before methods of this class are
48 * called. While some rudimentary checks are performed on the input,
49 * the checks are best effort and when performance is an overriding
50 * priority, as when methods of this class are optimized by the
51 * runtime compiler, some or all checks (if any) may be elided. Hence,
52 * the caller must not rely on the checks and corresponding
53 * exceptions!
54 *
55 * @author John R. Rose
56 * @see #getUnsafe
57 */
58 @AOTSafeClassInitializer
59 public final class Unsafe {
60
61 private static native void registerNatives();
62 static {
63 runtimeSetup();
64 }
65
66 /// BASE_OFFSET, INDEX_SCALE, and ADDRESS_SIZE fields are equivalent if the
67 /// AOT initialized heap is reused, so just register natives
68 @AOTRuntimeSetup
69 private static void runtimeSetup() {
70 registerNatives();
71 }
72
73 private Unsafe() {}
74
75 private static final Unsafe theUnsafe = new Unsafe();
76
77 /**
78 * Provides the caller with the capability of performing unsafe
79 * operations.
80 *
81 * <p>The returned {@code Unsafe} object should be carefully guarded
82 * by the caller, since it can be used to read and write data at arbitrary
83 * memory addresses. It must never be passed to untrusted code.
84 *
85 * <p>Most methods in this class are very low-level, and correspond to a
86 * small number of hardware instructions (on typical machines). Compilers
87 * are encouraged to optimize these methods accordingly.
88 *
89 * <p>Here is a suggested idiom for using unsafe operations:
90 *
91 * <pre> {@code
92 * class MyTrustedClass {
93 * private static final Unsafe unsafe = Unsafe.getUnsafe();
94 * ...
95 * private long myCountAddress = ...;
96 * public int getCount() { return unsafe.getByte(myCountAddress); }
97 * }}</pre>
98 *
99 * (It may assist compilers to make the local variable {@code final}.)
100 */
101 public static Unsafe getUnsafe() {
102 return theUnsafe;
103 }
104
105 //--- peek and poke operations
106 // (compilers should optimize these to memory ops)
107
108 // These work on object fields in the Java heap.
109 // They will not work on elements of packed arrays.
110
111 /**
112 * Fetches a value from a given Java variable.
113 * More specifically, fetches a field or array element within the given
114 * object {@code o} at the given offset, or (if {@code o} is null)
115 * from the memory address whose numerical value is the given offset.
116 * <p>
117 * The results are undefined unless one of the following cases is true:
118 * <ul>
119 * <li>The offset was obtained from {@link #objectFieldOffset} on
120 * the {@link java.lang.reflect.Field} of some Java field and the object
121 * referred to by {@code o} is of a class compatible with that
122 * field's class.
123 *
124 * <li>The offset and object reference {@code o} (either null or
125 * non-null) were both obtained via {@link #staticFieldOffset}
126 * and {@link #staticFieldBase} (respectively) from the
127 * reflective {@link Field} representation of some Java field.
128 *
129 * <li>The object referred to by {@code o} is an array, and the offset
130 * is an integer of the form {@code B+N*S}, where {@code N} is
131 * a valid index into the array, and {@code B} and {@code S} are
132 * the values obtained by {@link #arrayBaseOffset} and {@link
133 * #arrayIndexScale} (respectively) from the array's class. The value
134 * referred to is the {@code N}<em>th</em> element of the array.
135 *
136 * </ul>
137 * <p>
138 * If one of the above cases is true, the call references a specific Java
139 * variable (field or array element). However, the results are undefined
140 * if that variable is not in fact of the type returned by this method.
141 * <p>
142 * This method refers to a variable by means of two parameters, and so
143 * it provides (in effect) a <em>double-register</em> addressing mode
144 * for Java variables. When the object reference is null, this method
145 * uses its offset as an absolute address. This is similar in operation
146 * to methods such as {@link #getInt(long)}, which provide (in effect) a
147 * <em>single-register</em> addressing mode for non-Java variables.
148 * However, because Java variables may have a different layout in memory
149 * from non-Java variables, programmers should not assume that these
150 * two addressing modes are ever equivalent. Also, programmers should
151 * remember that offsets from the double-register addressing mode cannot
152 * be portably confused with longs used in the single-register addressing
153 * mode.
154 *
155 * @param o Java heap object in which the variable resides, if any, else
156 * null
157 * @param offset indication of where the variable resides in a Java heap
158 * object, if any, else a memory address locating the variable
159 * statically
160 * @return the value fetched from the indicated Java variable
161 * @throws RuntimeException No defined exceptions are thrown, not even
162 * {@link NullPointerException}
163 */
164 @IntrinsicCandidate
165 public native int getInt(Object o, long offset);
166
167 /**
168 * Stores a value into a given Java variable.
169 * <p>
170 * The first two parameters are interpreted exactly as with
171 * {@link #getInt(Object, long)} to refer to a specific
172 * Java variable (field or array element). The given value
173 * is stored into that variable.
174 * <p>
175 * The variable must be of the same type as the method
176 * parameter {@code x}.
177 *
178 * @param o Java heap object in which the variable resides, if any, else
179 * null
180 * @param offset indication of where the variable resides in a Java heap
181 * object, if any, else a memory address locating the variable
182 * statically
183 * @param x the value to store into the indicated Java variable
184 * @throws RuntimeException No defined exceptions are thrown, not even
185 * {@link NullPointerException}
186 */
187 @IntrinsicCandidate
188 public native void putInt(Object o, long offset, int x);
189
190
191 /**
192 * Returns true if the given field is flattened.
193 */
194 public boolean isFlatField(Field f) {
195 if (f == null) {
196 throw new NullPointerException();
197 }
198 return isFlatField0(f);
199 }
200
201 private native boolean isFlatField0(Object o);
202
203 /* Returns true if the given field has a null marker
204 * <p>
205 * Nullable flat fields are stored in a flattened representation
206 * and have an associated null marker to indicate if the the field value is
207 * null or the one stored with the flat representation
208 */
209
210 public boolean hasNullMarker(Field f) {
211 if (f == null) {
212 throw new NullPointerException();
213 }
214 return hasNullMarker0(f);
215 }
216
217 private native boolean hasNullMarker0(Object o);
218
219 /* Returns the offset of the null marker of the field,
220 * or -1 if the field doesn't have a null marker
221 */
222
223 public int nullMarkerOffset(Field f) {
224 if (f == null) {
225 throw new NullPointerException();
226 }
227 return nullMarkerOffset0(f);
228 }
229
230 private native int nullMarkerOffset0(Object o);
231
232 public static final int NON_FLAT_LAYOUT = 0;
233
234 /* Reports the kind of layout used for an element in the storage
235 * allocation of the given array. Do not expect to perform any logic
236 * or layout control with this value, it is just an opaque token
237 * used for performance reasons.
238 *
239 * A layout of 0 indicates this array is not flat.
240 */
241 public int arrayLayout(Object[] array) {
242 if (array == null) {
243 throw new NullPointerException();
244 }
245 return arrayLayout0(array);
246 }
247
248 private native int arrayLayout0(Object[] array);
249
250
251 /* Reports the kind of layout used for a given field in the storage
252 * allocation of its class. Do not expect to perform any logic
253 * or layout control with this value, it is just an opaque token
254 * used for performance reasons.
255 *
256 * A layout of 0 indicates this field is not flat.
257 */
258 public int fieldLayout(Field f) {
259 if (f == null) {
260 throw new NullPointerException();
261 }
262 return fieldLayout0(f);
263 }
264
265 private native int fieldLayout0(Object o);
266
267 public native Object[] newSpecialArray(Class<?> componentType,
268 int length, int layoutKind);
269
270 /**
271 * Fetches a reference value from a given Java variable.
272 * This method can return a reference to either an object or value
273 * or a null reference.
274 *
275 * @see #getInt(Object, long)
276 */
277 @IntrinsicCandidate
278 public native Object getReference(Object o, long offset);
279
280 /**
281 * Stores a reference value into a given Java variable.
282 * This method can store a reference to either an object or value
283 * or a null reference.
284 * <p>
285 * Unless the reference {@code x} being stored is either null
286 * or matches the field type, the results are undefined.
287 * If the reference {@code o} is non-null, card marks or
288 * other store barriers for that object (if the VM requires them)
289 * are updated.
290 * @see #putInt(Object, long, int)
291 */
292 @IntrinsicCandidate
293 public native void putReference(Object o, long offset, Object x);
294
295 /**
296 * Fetches a value of type {@code <V>} from a given Java variable.
297 * More specifically, fetches a field or array element within the given
298 * {@code o} object at the given offset, or (if {@code o} is null)
299 * from the memory address whose numerical value is the given offset.
300 *
301 * @param o Java heap object in which the variable resides, if any, else
302 * null
303 * @param offset indication of where the variable resides in a Java heap
304 * object, if any, else a memory address locating the variable
305 * statically
306 * @param valueType value type
307 * @param <V> the type of a value
308 * @return the value fetched from the indicated Java variable
309 * @throws RuntimeException No defined exceptions are thrown, not even
310 * {@link NullPointerException}
311 */
312 @IntrinsicCandidate
313 public native <V> V getValue(Object o, long offset, Class<?> valueType);
314
315 /**
316 * Fetches a value of type {@code <V>} from a given Java variable.
317 * More specifically, fetches a field or array element within the given
318 * {@code o} object at the given offset, or (if {@code o} is null)
319 * from the memory address whose numerical value is the given offset.
320 *
321 * @param o Java heap object in which the variable resides, if any, else
322 * null
323 * @param offset indication of where the variable resides in a Java heap
324 * object, if any, else a memory address locating the variable
325 * statically
326 * @param layoutKind opaque value used by the VM to know the layout
327 * the field or array element. This value must be retrieved with
328 * {@link #fieldLayout} or {@link #arrayLayout}.
329 * @param valueType value type
330 * @param <V> the type of a value
331 * @return the value fetched from the indicated Java variable
332 * @throws RuntimeException No defined exceptions are thrown, not even
333 * {@link NullPointerException}
334 */
335 @IntrinsicCandidate
336 public native <V> V getFlatValue(Object o, long offset, int layoutKind, Class<?> valueType);
337
338
339 /**
340 * Stores the given value into a given Java variable.
341 *
342 * Unless the reference {@code o} being stored is either null
343 * or matches the field type, the results are undefined.
344 *
345 * @param o Java heap object in which the variable resides, if any, else
346 * null
347 * @param offset indication of where the variable resides in a Java heap
348 * object, if any, else a memory address locating the variable
349 * statically
350 * @param valueType value type
351 * @param v the value to store into the indicated Java variable
352 * @param <V> the type of a value
353 * @throws RuntimeException No defined exceptions are thrown, not even
354 * {@link NullPointerException}
355 */
356 @IntrinsicCandidate
357 public native <V> void putValue(Object o, long offset, Class<?> valueType, V v);
358
359 /**
360 * Stores the given value into a given Java variable.
361 *
362 * Unless the reference {@code o} being stored is either null
363 * or matches the field type, the results are undefined.
364 *
365 * @param o Java heap object in which the variable resides, if any, else
366 * null
367 * @param offset indication of where the variable resides in a Java heap
368 * object, if any, else a memory address locating the variable
369 * statically
370 * @param layoutKind opaque value used by the VM to know the layout
371 * the field or array element. This value must be retrieved with
372 * {@link #fieldLayout} or {@link #arrayLayout}.
373 * @param valueType value type
374 * @param v the value to store into the indicated Java variable
375 * @param <V> the type of a value
376 * @throws RuntimeException No defined exceptions are thrown, not even
377 * {@link NullPointerException}
378 */
379 @IntrinsicCandidate
380 public native <V> void putFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, V v);
381
382 /**
383 * Returns an object instance with a private buffered value whose layout
384 * and contents is exactly the given value instance. The return object
385 * is in the larval state that can be updated using the unsafe put operation.
386 *
387 * @param value a value instance
388 * @param <V> the type of the given value instance
389 */
390 @IntrinsicCandidate
391 public native <V> V makePrivateBuffer(V value);
392
393 /**
394 * Exits the larval state and returns a value instance.
395 *
396 * @param value a value instance
397 * @param <V> the type of the given value instance
398 */
399 @IntrinsicCandidate
400 public native <V> V finishPrivateBuffer(V value);
401
402 /**
403 * Returns the header size of the given value type.
404 *
405 * @param valueType value type
406 * @return the header size of the value type
407 */
408 public native <V> long valueHeaderSize(Class<V> valueType);
409
410 /** @see #getInt(Object, long) */
411 @IntrinsicCandidate
412 public native boolean getBoolean(Object o, long offset);
413
414 /** @see #putInt(Object, long, int) */
415 @IntrinsicCandidate
416 public native void putBoolean(Object o, long offset, boolean x);
417
418 /** @see #getInt(Object, long) */
419 @IntrinsicCandidate
420 public native byte getByte(Object o, long offset);
421
422 /** @see #putInt(Object, long, int) */
423 @IntrinsicCandidate
424 public native void putByte(Object o, long offset, byte x);
425
426 /** @see #getInt(Object, long) */
427 @IntrinsicCandidate
428 public native short getShort(Object o, long offset);
429
430 /** @see #putInt(Object, long, int) */
431 @IntrinsicCandidate
432 public native void putShort(Object o, long offset, short x);
433
434 /** @see #getInt(Object, long) */
435 @IntrinsicCandidate
436 public native char getChar(Object o, long offset);
437
438 /** @see #putInt(Object, long, int) */
439 @IntrinsicCandidate
440 public native void putChar(Object o, long offset, char x);
441
442 /** @see #getInt(Object, long) */
443 @IntrinsicCandidate
444 public native long getLong(Object o, long offset);
445
446 /** @see #putInt(Object, long, int) */
447 @IntrinsicCandidate
448 public native void putLong(Object o, long offset, long x);
449
450 /** @see #getInt(Object, long) */
451 @IntrinsicCandidate
452 public native float getFloat(Object o, long offset);
453
454 /** @see #putInt(Object, long, int) */
455 @IntrinsicCandidate
456 public native void putFloat(Object o, long offset, float x);
457
458 /** @see #getInt(Object, long) */
459 @IntrinsicCandidate
460 public native double getDouble(Object o, long offset);
461
462 /** @see #putInt(Object, long, int) */
463 @IntrinsicCandidate
464 public native void putDouble(Object o, long offset, double x);
465
466 /**
467 * Fetches a native pointer from a given memory address. If the address is
468 * zero, or does not point into a block obtained from {@link
469 * #allocateMemory}, the results are undefined.
470 *
471 * <p>If the native pointer is less than 64 bits wide, it is extended as
472 * an unsigned number to a Java long. The pointer may be indexed by any
473 * given byte offset, simply by adding that offset (as a simple integer) to
474 * the long representing the pointer. The number of bytes actually read
475 * from the target address may be determined by consulting {@link
476 * #addressSize}.
477 *
478 * @see #allocateMemory
479 * @see #getInt(Object, long)
480 */
481 @ForceInline
482 public long getAddress(Object o, long offset) {
483 if (ADDRESS_SIZE == 4) {
484 return Integer.toUnsignedLong(getInt(o, offset));
485 } else {
486 return getLong(o, offset);
487 }
488 }
489
490 /**
491 * Stores a native pointer into a given memory address. If the address is
492 * zero, or does not point into a block obtained from {@link
493 * #allocateMemory}, the results are undefined.
494 *
495 * <p>The number of bytes actually written at the target address may be
496 * determined by consulting {@link #addressSize}.
497 *
498 * @see #allocateMemory
499 * @see #putInt(Object, long, int)
500 */
501 @ForceInline
502 public void putAddress(Object o, long offset, long x) {
503 if (ADDRESS_SIZE == 4) {
504 putInt(o, offset, (int)x);
505 } else {
506 putLong(o, offset, x);
507 }
508 }
509
510 // These read VM internal data.
511
512 /**
513 * Fetches an uncompressed reference value from a given native variable
514 * ignoring the VM's compressed references mode.
515 *
516 * @param address a memory address locating the variable
517 * @return the value fetched from the indicated native variable
518 */
519 public native Object getUncompressedObject(long address);
520
521 // These work on values in the C heap.
522
523 /**
524 * Fetches a value from a given memory address. If the address is zero, or
525 * does not point into a block obtained from {@link #allocateMemory}, the
526 * results are undefined.
527 *
528 * @see #allocateMemory
529 */
530 @ForceInline
531 public byte getByte(long address) {
532 return getByte(null, address);
533 }
534
535 /**
536 * Stores a value into a given memory address. If the address is zero, or
537 * does not point into a block obtained from {@link #allocateMemory}, the
538 * results are undefined.
539 *
540 * @see #getByte(long)
541 */
542 @ForceInline
543 public void putByte(long address, byte x) {
544 putByte(null, address, x);
545 }
546
547 /** @see #getByte(long) */
548 @ForceInline
549 public short getShort(long address) {
550 return getShort(null, address);
551 }
552
553 /** @see #putByte(long, byte) */
554 @ForceInline
555 public void putShort(long address, short x) {
556 putShort(null, address, x);
557 }
558
559 /** @see #getByte(long) */
560 @ForceInline
561 public char getChar(long address) {
562 return getChar(null, address);
563 }
564
565 /** @see #putByte(long, byte) */
566 @ForceInline
567 public void putChar(long address, char x) {
568 putChar(null, address, x);
569 }
570
571 /** @see #getByte(long) */
572 @ForceInline
573 public int getInt(long address) {
574 return getInt(null, address);
575 }
576
577 /** @see #putByte(long, byte) */
578 @ForceInline
579 public void putInt(long address, int x) {
580 putInt(null, address, x);
581 }
582
583 /** @see #getByte(long) */
584 @ForceInline
585 public long getLong(long address) {
586 return getLong(null, address);
587 }
588
589 /** @see #putByte(long, byte) */
590 @ForceInline
591 public void putLong(long address, long x) {
592 putLong(null, address, x);
593 }
594
595 /** @see #getByte(long) */
596 @ForceInline
597 public float getFloat(long address) {
598 return getFloat(null, address);
599 }
600
601 /** @see #putByte(long, byte) */
602 @ForceInline
603 public void putFloat(long address, float x) {
604 putFloat(null, address, x);
605 }
606
607 /** @see #getByte(long) */
608 @ForceInline
609 public double getDouble(long address) {
610 return getDouble(null, address);
611 }
612
613 /** @see #putByte(long, byte) */
614 @ForceInline
615 public void putDouble(long address, double x) {
616 putDouble(null, address, x);
617 }
618
619 /** @see #getAddress(Object, long) */
620 @ForceInline
621 public long getAddress(long address) {
622 return getAddress(null, address);
623 }
624
625 /** @see #putAddress(Object, long, long) */
626 @ForceInline
627 public void putAddress(long address, long x) {
628 putAddress(null, address, x);
629 }
630
631
632
633 //--- helper methods for validating various types of objects/values
634
635 /**
636 * Create an exception reflecting that some of the input was invalid
637 *
638 * <em>Note:</em> It is the responsibility of the caller to make
639 * sure arguments are checked before the methods are called. While
640 * some rudimentary checks are performed on the input, the checks
641 * are best effort and when performance is an overriding priority,
642 * as when methods of this class are optimized by the runtime
643 * compiler, some or all checks (if any) may be elided. Hence, the
644 * caller must not rely on the checks and corresponding
645 * exceptions!
646 *
647 * @return an exception object
648 */
649 private RuntimeException invalidInput() {
650 return new IllegalArgumentException();
651 }
652
653 /**
654 * Check if a value is 32-bit clean (32 MSB are all zero)
655 *
656 * @param value the 64-bit value to check
657 *
658 * @return true if the value is 32-bit clean
659 */
660 private boolean is32BitClean(long value) {
661 return value >>> 32 == 0;
662 }
663
664 /**
665 * Check the validity of a size (the equivalent of a size_t)
666 *
667 * @throws RuntimeException if the size is invalid
668 * (<em>Note:</em> after optimization, invalid inputs may
669 * go undetected, which will lead to unpredictable
670 * behavior)
671 */
672 private void checkSize(long size) {
673 if (ADDRESS_SIZE == 4) {
674 // Note: this will also check for negative sizes
675 if (!is32BitClean(size)) {
676 throw invalidInput();
677 }
678 } else if (size < 0) {
679 throw invalidInput();
680 }
681 }
682
683 /**
684 * Check the validity of a native address (the equivalent of void*)
685 *
686 * @throws RuntimeException if the address is invalid
687 * (<em>Note:</em> after optimization, invalid inputs may
688 * go undetected, which will lead to unpredictable
689 * behavior)
690 */
691 private void checkNativeAddress(long address) {
692 if (ADDRESS_SIZE == 4) {
693 // Accept both zero and sign extended pointers. A valid
694 // pointer will, after the +1 below, either have produced
695 // the value 0x0 or 0x1. Masking off the low bit allows
696 // for testing against 0.
697 if ((((address >> 32) + 1) & ~1) != 0) {
698 throw invalidInput();
699 }
700 }
701 }
702
703 /**
704 * Check the validity of an offset, relative to a base object
705 *
706 * @param o the base object
707 * @param offset the offset to check
708 *
709 * @throws RuntimeException if the size is invalid
710 * (<em>Note:</em> after optimization, invalid inputs may
711 * go undetected, which will lead to unpredictable
712 * behavior)
713 */
714 private void checkOffset(Object o, long offset) {
715 if (ADDRESS_SIZE == 4) {
716 // Note: this will also check for negative offsets
717 if (!is32BitClean(offset)) {
718 throw invalidInput();
719 }
720 } else if (offset < 0) {
721 throw invalidInput();
722 }
723 }
724
725 /**
726 * Check the validity of a double-register pointer
727 *
728 * Note: This code deliberately does *not* check for NPE for (at
729 * least) three reasons:
730 *
731 * 1) NPE is not just NULL/0 - there is a range of values all
732 * resulting in an NPE, which is not trivial to check for
733 *
734 * 2) It is the responsibility of the callers of Unsafe methods
735 * to verify the input, so throwing an exception here is not really
736 * useful - passing in a NULL pointer is a critical error and the
737 * must not expect an exception to be thrown anyway.
738 *
739 * 3) the actual operations will detect NULL pointers anyway by
740 * means of traps and signals (like SIGSEGV).
741 *
742 * @param o Java heap object, or null
743 * @param offset indication of where the variable resides in a Java heap
744 * object, if any, else a memory address locating the variable
745 * statically
746 *
747 * @throws RuntimeException if the pointer is invalid
748 * (<em>Note:</em> after optimization, invalid inputs may
749 * go undetected, which will lead to unpredictable
750 * behavior)
751 */
752 private void checkPointer(Object o, long offset) {
753 if (o == null) {
754 checkNativeAddress(offset);
755 } else {
756 checkOffset(o, offset);
757 }
758 }
759
760 /**
761 * Check if a type is a primitive array type
762 *
763 * @param c the type to check
764 *
765 * @return true if the type is a primitive array type
766 */
767 private void checkPrimitiveArray(Class<?> c) {
768 Class<?> componentType = c.getComponentType();
769 if (componentType == null || !componentType.isPrimitive()) {
770 throw invalidInput();
771 }
772 }
773
774 /**
775 * Check that a pointer is a valid primitive array type pointer
776 *
777 * Note: pointers off-heap are considered to be primitive arrays
778 *
779 * @throws RuntimeException if the pointer is invalid
780 * (<em>Note:</em> after optimization, invalid inputs may
781 * go undetected, which will lead to unpredictable
782 * behavior)
783 */
784 private void checkPrimitivePointer(Object o, long offset) {
785 checkPointer(o, offset);
786
787 if (o != null) {
788 // If on heap, it must be a primitive array
789 checkPrimitiveArray(o.getClass());
790 }
791 }
792
793
794 //--- wrappers for malloc, realloc, free:
795
796 /**
797 * Round up allocation size to a multiple of HeapWordSize.
798 */
799 private long alignToHeapWordSize(long bytes) {
800 if (bytes >= 0) {
801 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
802 } else {
803 throw invalidInput();
804 }
805 }
806
807 /**
808 * Allocates a new block of native memory, of the given size in bytes. The
809 * contents of the memory are uninitialized; they will generally be
810 * garbage. The resulting native pointer will be zero if and only if the
811 * requested size is zero. The resulting native pointer will be aligned for
812 * all value types. Dispose of this memory by calling {@link #freeMemory}
813 * or resize it with {@link #reallocateMemory}.
814 *
815 * <em>Note:</em> It is the responsibility of the caller to make
816 * sure arguments are checked before the methods are called. While
817 * some rudimentary checks are performed on the input, the checks
818 * are best effort and when performance is an overriding priority,
819 * as when methods of this class are optimized by the runtime
820 * compiler, some or all checks (if any) may be elided. Hence, the
821 * caller must not rely on the checks and corresponding
822 * exceptions!
823 *
824 * @throws RuntimeException if the size is negative or too large
825 * for the native size_t type
826 *
827 * @throws OutOfMemoryError if the allocation is refused by the system
828 *
829 * @see #getByte(long)
830 * @see #putByte(long, byte)
831 */
832 public long allocateMemory(long bytes) {
833 bytes = alignToHeapWordSize(bytes);
834
835 allocateMemoryChecks(bytes);
836
837 if (bytes == 0) {
838 return 0;
839 }
840
841 long p = allocateMemory0(bytes);
842 if (p == 0) {
843 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
844 }
845
846 return p;
847 }
848
849 /**
850 * Validate the arguments to allocateMemory
851 *
852 * @throws RuntimeException if the arguments are invalid
853 * (<em>Note:</em> after optimization, invalid inputs may
854 * go undetected, which will lead to unpredictable
855 * behavior)
856 */
857 private void allocateMemoryChecks(long bytes) {
858 checkSize(bytes);
859 }
860
861 /**
862 * Resizes a new block of native memory, to the given size in bytes. The
863 * contents of the new block past the size of the old block are
864 * uninitialized; they will generally be garbage. The resulting native
865 * pointer will be zero if and only if the requested size is zero. The
866 * resulting native pointer will be aligned for all value types. Dispose
867 * of this memory by calling {@link #freeMemory}, or resize it with {@link
868 * #reallocateMemory}. The address passed to this method may be null, in
869 * which case an allocation will be performed.
870 *
871 * <em>Note:</em> It is the responsibility of the caller to make
872 * sure arguments are checked before the methods are called. While
873 * some rudimentary checks are performed on the input, the checks
874 * are best effort and when performance is an overriding priority,
875 * as when methods of this class are optimized by the runtime
876 * compiler, some or all checks (if any) may be elided. Hence, the
877 * caller must not rely on the checks and corresponding
878 * exceptions!
879 *
880 * @throws RuntimeException if the size is negative or too large
881 * for the native size_t type
882 *
883 * @throws OutOfMemoryError if the allocation is refused by the system
884 *
885 * @see #allocateMemory
886 */
887 public long reallocateMemory(long address, long bytes) {
888 bytes = alignToHeapWordSize(bytes);
889
890 reallocateMemoryChecks(address, bytes);
891
892 if (bytes == 0) {
893 freeMemory(address);
894 return 0;
895 }
896
897 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
898 if (p == 0) {
899 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
900 }
901
902 return p;
903 }
904
905 /**
906 * Validate the arguments to reallocateMemory
907 *
908 * @throws RuntimeException if the arguments are invalid
909 * (<em>Note:</em> after optimization, invalid inputs may
910 * go undetected, which will lead to unpredictable
911 * behavior)
912 */
913 private void reallocateMemoryChecks(long address, long bytes) {
914 checkPointer(null, address);
915 checkSize(bytes);
916 }
917
918 /**
919 * Sets all bytes in a given block of memory to a fixed value
920 * (usually zero).
921 *
922 * <p>This method determines a block's base address by means of two parameters,
923 * and so it provides (in effect) a <em>double-register</em> addressing mode,
924 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
925 * the offset supplies an absolute base address.
926 *
927 * <p>The stores are in coherent (atomic) units of a size determined
928 * by the address and length parameters. If the effective address and
929 * length are all even modulo 8, the stores take place in 'long' units.
930 * If the effective address and length are (resp.) even modulo 4 or 2,
931 * the stores take place in units of 'int' or 'short'.
932 *
933 * <em>Note:</em> It is the responsibility of the caller to make
934 * sure arguments are checked before the methods are called. While
935 * some rudimentary checks are performed on the input, the checks
936 * are best effort and when performance is an overriding priority,
937 * as when methods of this class are optimized by the runtime
938 * compiler, some or all checks (if any) may be elided. Hence, the
939 * caller must not rely on the checks and corresponding
940 * exceptions!
941 *
942 * @throws RuntimeException if any of the arguments is invalid
943 *
944 * @since 1.7
945 */
946 public void setMemory(Object o, long offset, long bytes, byte value) {
947 setMemoryChecks(o, offset, bytes, value);
948
949 if (bytes == 0) {
950 return;
951 }
952
953 setMemory0(o, offset, bytes, value);
954 }
955
956 /**
957 * Sets all bytes in a given block of memory to a fixed value
958 * (usually zero). This provides a <em>single-register</em> addressing mode,
959 * as discussed in {@link #getInt(Object,long)}.
960 *
961 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
962 */
963 public void setMemory(long address, long bytes, byte value) {
964 setMemory(null, address, bytes, value);
965 }
966
967 /**
968 * Validate the arguments to setMemory
969 *
970 * @throws RuntimeException if the arguments are invalid
971 * (<em>Note:</em> after optimization, invalid inputs may
972 * go undetected, which will lead to unpredictable
973 * behavior)
974 */
975 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
976 checkPrimitivePointer(o, offset);
977 checkSize(bytes);
978 }
979
980 /**
981 * Sets all bytes in a given block of memory to a copy of another
982 * block.
983 *
984 * <p>This method determines each block's base address by means of two parameters,
985 * and so it provides (in effect) a <em>double-register</em> addressing mode,
986 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
987 * the offset supplies an absolute base address.
988 *
989 * <p>The transfers are in coherent (atomic) units of a size determined
990 * by the address and length parameters. If the effective addresses and
991 * length are all even modulo 8, the transfer takes place in 'long' units.
992 * If the effective addresses and length are (resp.) even modulo 4 or 2,
993 * the transfer takes place in units of 'int' or 'short'.
994 *
995 * <em>Note:</em> It is the responsibility of the caller to make
996 * sure arguments are checked before the methods are called. While
997 * some rudimentary checks are performed on the input, the checks
998 * are best effort and when performance is an overriding priority,
999 * as when methods of this class are optimized by the runtime
1000 * compiler, some or all checks (if any) may be elided. Hence, the
1001 * caller must not rely on the checks and corresponding
1002 * exceptions!
1003 *
1004 * @throws RuntimeException if any of the arguments is invalid
1005 *
1006 * @since 1.7
1007 */
1008 public void copyMemory(Object srcBase, long srcOffset,
1009 Object destBase, long destOffset,
1010 long bytes) {
1011 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
1012
1013 if (bytes == 0) {
1014 return;
1015 }
1016
1017 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
1018 }
1019
1020 /**
1021 * Sets all bytes in a given block of memory to a copy of another
1022 * block. This provides a <em>single-register</em> addressing mode,
1023 * as discussed in {@link #getInt(Object,long)}.
1024 *
1025 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
1026 */
1027 public void copyMemory(long srcAddress, long destAddress, long bytes) {
1028 copyMemory(null, srcAddress, null, destAddress, bytes);
1029 }
1030
1031 /**
1032 * Validate the arguments to copyMemory
1033 *
1034 * @throws RuntimeException if any of the arguments is invalid
1035 * (<em>Note:</em> after optimization, invalid inputs may
1036 * go undetected, which will lead to unpredictable
1037 * behavior)
1038 */
1039 private void copyMemoryChecks(Object srcBase, long srcOffset,
1040 Object destBase, long destOffset,
1041 long bytes) {
1042 checkSize(bytes);
1043 checkPrimitivePointer(srcBase, srcOffset);
1044 checkPrimitivePointer(destBase, destOffset);
1045 }
1046
1047 /**
1048 * Copies all elements from one block of memory to another block,
1049 * *unconditionally* byte swapping the elements on the fly.
1050 *
1051 * <p>This method determines each block's base address by means of two parameters,
1052 * and so it provides (in effect) a <em>double-register</em> addressing mode,
1053 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
1054 * the offset supplies an absolute base address.
1055 *
1056 * <em>Note:</em> It is the responsibility of the caller to make
1057 * sure arguments are checked before the methods are called. While
1058 * some rudimentary checks are performed on the input, the checks
1059 * are best effort and when performance is an overriding priority,
1060 * as when methods of this class are optimized by the runtime
1061 * compiler, some or all checks (if any) may be elided. Hence, the
1062 * caller must not rely on the checks and corresponding
1063 * exceptions!
1064 *
1065 * @throws RuntimeException if any of the arguments is invalid
1066 *
1067 * @since 9
1068 */
1069 public void copySwapMemory(Object srcBase, long srcOffset,
1070 Object destBase, long destOffset,
1071 long bytes, long elemSize) {
1072 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1073
1074 if (bytes == 0) {
1075 return;
1076 }
1077
1078 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1079 }
1080
1081 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
1082 Object destBase, long destOffset,
1083 long bytes, long elemSize) {
1084 checkSize(bytes);
1085
1086 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
1087 throw invalidInput();
1088 }
1089 if (bytes % elemSize != 0) {
1090 throw invalidInput();
1091 }
1092
1093 checkPrimitivePointer(srcBase, srcOffset);
1094 checkPrimitivePointer(destBase, destOffset);
1095 }
1096
1097 /**
1098 * Copies all elements from one block of memory to another block, byte swapping the
1099 * elements on the fly.
1100 *
1101 * This provides a <em>single-register</em> addressing mode, as
1102 * discussed in {@link #getInt(Object,long)}.
1103 *
1104 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
1105 */
1106 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
1107 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
1108 }
1109
1110 /**
1111 * Disposes of a block of native memory, as obtained from {@link
1112 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
1113 * this method may be null, in which case no action is taken.
1114 *
1115 * <em>Note:</em> It is the responsibility of the caller to make
1116 * sure arguments are checked before the methods are called. While
1117 * some rudimentary checks are performed on the input, the checks
1118 * are best effort and when performance is an overriding priority,
1119 * as when methods of this class are optimized by the runtime
1120 * compiler, some or all checks (if any) may be elided. Hence, the
1121 * caller must not rely on the checks and corresponding
1122 * exceptions!
1123 *
1124 * @throws RuntimeException if any of the arguments is invalid
1125 *
1126 * @see #allocateMemory
1127 */
1128 public void freeMemory(long address) {
1129 freeMemoryChecks(address);
1130
1131 if (address == 0) {
1132 return;
1133 }
1134
1135 freeMemory0(address);
1136 }
1137
1138 /**
1139 * Validate the arguments to freeMemory
1140 *
1141 * @throws RuntimeException if the arguments are invalid
1142 * (<em>Note:</em> after optimization, invalid inputs may
1143 * go undetected, which will lead to unpredictable
1144 * behavior)
1145 */
1146 private void freeMemoryChecks(long address) {
1147 checkPointer(null, address);
1148 }
1149
1150 /**
1151 * Ensure writeback of a specified virtual memory address range
1152 * from cache to physical memory. All bytes in the address range
1153 * are guaranteed to have been written back to physical memory on
1154 * return from this call i.e. subsequently executed store
1155 * instructions are guaranteed not to be visible before the
1156 * writeback is completed.
1157 *
1158 * @param address
1159 * the lowest byte address that must be guaranteed written
1160 * back to memory. bytes at lower addresses may also be
1161 * written back.
1162 *
1163 * @param length
1164 * the length in bytes of the region starting at address
1165 * that must be guaranteed written back to memory.
1166 *
1167 * @throws RuntimeException if memory writeback is not supported
1168 * on the current hardware of if the arguments are invalid.
1169 * (<em>Note:</em> after optimization, invalid inputs may
1170 * go undetected, which will lead to unpredictable
1171 * behavior)
1172 *
1173 * @since 14
1174 */
1175
1176 public void writebackMemory(long address, long length) {
1177 checkWritebackEnabled();
1178 checkWritebackMemory(address, length);
1179
1180 // perform any required pre-writeback barrier
1181 writebackPreSync0();
1182
1183 // write back one cache line at a time
1184 long line = dataCacheLineAlignDown(address);
1185 long end = address + length;
1186 while (line < end) {
1187 writeback0(line);
1188 line += dataCacheLineFlushSize();
1189 }
1190
1191 // perform any required post-writeback barrier
1192 writebackPostSync0();
1193 }
1194
1195 /**
1196 * Validate the arguments to writebackMemory
1197 *
1198 * @throws RuntimeException if the arguments are invalid
1199 * (<em>Note:</em> after optimization, invalid inputs may
1200 * go undetected, which will lead to unpredictable
1201 * behavior)
1202 */
1203 private void checkWritebackMemory(long address, long length) {
1204 checkNativeAddress(address);
1205 checkSize(length);
1206 }
1207
1208 /**
1209 * Validate that the current hardware supports memory writeback.
1210 * (<em>Note:</em> this is a belt and braces check. Clients are
1211 * expected to test whether writeback is enabled by calling
1212 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1213 * calling method {@link writeback #writeback} if it is disabled).
1214 *
1215 *
1216 * @throws RuntimeException if memory writeback is not supported
1217 */
1218 private void checkWritebackEnabled() {
1219 if (!isWritebackEnabled()) {
1220 throw new RuntimeException("writebackMemory not enabled!");
1221 }
1222 }
1223
1224 /**
1225 * force writeback of an individual cache line.
1226 *
1227 * @param address
1228 * the start address of the cache line to be written back
1229 */
1230 @IntrinsicCandidate
1231 private native void writeback0(long address);
1232
1233 /**
1234 * Serialize writeback operations relative to preceding memory writes.
1235 */
1236 @IntrinsicCandidate
1237 private native void writebackPreSync0();
1238
1239 /**
1240 * Serialize writeback operations relative to following memory writes.
1241 */
1242 @IntrinsicCandidate
1243 private native void writebackPostSync0();
1244
1245 //--- random queries
1246
1247 /**
1248 * This constant differs from all results that will ever be returned from
1249 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1250 * or {@link #arrayBaseOffset}.
1251 * <p>
1252 * The static type is @code long} to emphasize that long arithmetic should
1253 * always be used for offset calculations to avoid overflows.
1254 */
1255 public static final long INVALID_FIELD_OFFSET = -1;
1256
1257 /**
1258 * Reports the location of a given field in the storage allocation of its
1259 * class. Do not expect to perform any sort of arithmetic on this offset;
1260 * it is just a cookie which is passed to the unsafe heap memory accessors.
1261 *
1262 * <p>Any given field will always have the same offset and base, and no
1263 * two distinct fields of the same class will ever have the same offset
1264 * and base.
1265 *
1266 * <p>As of 1.4.1, offsets for fields are represented as long values,
1267 * although the Sun JVM does not use the most significant 32 bits.
1268 * However, JVM implementations which store static fields at absolute
1269 * addresses can use long offsets and null base pointers to express
1270 * the field locations in a form usable by {@link #getInt(Object,long)}.
1271 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1272 * must preserve all bits of static field offsets.
1273 *
1274 * @throws NullPointerException if the field is {@code null}
1275 * @throws IllegalArgumentException if the field is static
1276 * @see #getInt(Object, long)
1277 */
1278 public long objectFieldOffset(Field f) {
1279 if (f == null) {
1280 throw new NullPointerException();
1281 }
1282
1283 return objectFieldOffset0(f);
1284 }
1285
1286 /**
1287 * (For compile-time known instance fields in JDK code only) Reports the
1288 * location of the field with a given name in the storage allocation of its
1289 * class.
1290 * <p>
1291 * This API is used to avoid creating reflective Objects in Java code at
1292 * startup. This should not be used to find fields in non-trusted code.
1293 * Use the {@link #objectFieldOffset(Field) Field}-accepting version for
1294 * arbitrary fields instead.
1295 *
1296 * @throws NullPointerException if any parameter is {@code null}.
1297 * @throws InternalError if the presumably known field couldn't be found
1298 *
1299 * @see #objectFieldOffset(Field)
1300 */
1301 public long objectFieldOffset(Class<?> c, String name) {
1302 if (c == null || name == null) {
1303 throw new NullPointerException();
1304 }
1305
1306 long result = knownObjectFieldOffset0(c, name);
1307 if (result < 0) {
1308 String type = switch ((int) result) {
1309 case -2 -> "a static field";
1310 case -1 -> "not found";
1311 default -> "unknown";
1312 };
1313 throw new InternalError("Field %s.%s %s".formatted(c.getTypeName(), name, type));
1314 }
1315 return result;
1316 }
1317
1318 /**
1319 * Reports the location of a given static field, in conjunction with {@link
1320 * #staticFieldBase}.
1321 * <p>Do not expect to perform any sort of arithmetic on this offset;
1322 * it is just a cookie which is passed to the unsafe heap memory accessors.
1323 *
1324 * <p>Any given field will always have the same offset, and no two distinct
1325 * fields of the same class will ever have the same offset.
1326 *
1327 * <p>As of 1.4.1, offsets for fields are represented as long values,
1328 * although the Sun JVM does not use the most significant 32 bits.
1329 * It is hard to imagine a JVM technology which needs more than
1330 * a few bits to encode an offset within a non-array object,
1331 * However, for consistency with other methods in this class,
1332 * this method reports its result as a long value.
1333 *
1334 * @throws NullPointerException if the field is {@code null}
1335 * @throws IllegalArgumentException if the field is not static
1336 * @see #getInt(Object, long)
1337 */
1338 public long staticFieldOffset(Field f) {
1339 if (f == null) {
1340 throw new NullPointerException();
1341 }
1342
1343 return staticFieldOffset0(f);
1344 }
1345
1346 /**
1347 * Reports the location of a given static field, in conjunction with {@link
1348 * #staticFieldOffset}.
1349 * <p>Fetch the base "Object", if any, with which static fields of the
1350 * given class can be accessed via methods like {@link #getInt(Object,
1351 * long)}. This value may be null. This value may refer to an object
1352 * which is a "cookie", not guaranteed to be a real Object, and it should
1353 * not be used in any way except as argument to the get and put routines in
1354 * this class.
1355 *
1356 * @throws NullPointerException if the field is {@code null}
1357 * @throws IllegalArgumentException if the field is not static
1358 */
1359 public Object staticFieldBase(Field f) {
1360 if (f == null) {
1361 throw new NullPointerException();
1362 }
1363
1364 return staticFieldBase0(f);
1365 }
1366
1367 /**
1368 * Detects if the given class may need to be initialized. This is often
1369 * needed in conjunction with obtaining the static field base of a
1370 * class.
1371 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1372 */
1373 public boolean shouldBeInitialized(Class<?> c) {
1374 if (c == null) {
1375 throw new NullPointerException();
1376 }
1377
1378 return shouldBeInitialized0(c);
1379 }
1380
1381 /**
1382 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1383 * This is often needed in conjunction with obtaining the static field base
1384 * of a class.
1385 *
1386 * The call returns when either class {@code c} is fully initialized or
1387 * class {@code c} is being initialized and the call is performed from
1388 * the initializing thread. In the latter case a subsequent call to
1389 * {@link #shouldBeInitialized} will return {@code true}.
1390 */
1391 public void ensureClassInitialized(Class<?> c) {
1392 if (c == null) {
1393 throw new NullPointerException();
1394 }
1395
1396 ensureClassInitialized0(c);
1397 }
1398
1399 /**
1400 * The reading or writing of strict static fields may require
1401 * special processing. Notify the VM that such an event is about
1402 * to happen. The VM may respond by throwing an exception, in the
1403 * case of a read of an uninitialized field. If the VM allows the
1404 * method to return normally, no further calls are needed, with
1405 * the same arguments.
1406 */
1407 public void notifyStrictStaticAccess(Class<?> c, long staticFieldOffset, boolean writing) {
1408 if (c == null) {
1409 throw new NullPointerException();
1410 }
1411 notifyStrictStaticAccess0(c, staticFieldOffset, writing);
1412 }
1413
1414 /**
1415 * Reports the offset of the first element in the storage allocation of a
1416 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1417 * for the same class, you may use that scale factor, together with this
1418 * base offset, to form new offsets to access elements of arrays of the
1419 * given class.
1420 * <p>
1421 * The return value is in the range of a {@code int}. The return type is
1422 * {@code long} to emphasize that long arithmetic should always be used
1423 * for offset calculations to avoid overflows.
1424 *
1425 * @see #getInt(Object, long)
1426 * @see #putInt(Object, long, int)
1427 */
1428 public long arrayBaseOffset(Class<?> arrayClass) {
1429 if (arrayClass == null) {
1430 throw new NullPointerException();
1431 }
1432
1433 return arrayBaseOffset0(arrayClass);
1434 }
1435
1436 public long arrayBaseOffset(Object[] array) {
1437 if (array == null) {
1438 throw new NullPointerException();
1439 }
1440
1441 return arrayBaseOffset1(array);
1442 }
1443
1444 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1445 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1446 = theUnsafe.arrayBaseOffset(boolean[].class);
1447
1448 /** The value of {@code arrayBaseOffset(byte[].class)} */
1449 public static final long ARRAY_BYTE_BASE_OFFSET
1450 = theUnsafe.arrayBaseOffset(byte[].class);
1451
1452 /** The value of {@code arrayBaseOffset(short[].class)} */
1453 public static final long ARRAY_SHORT_BASE_OFFSET
1454 = theUnsafe.arrayBaseOffset(short[].class);
1455
1456 /** The value of {@code arrayBaseOffset(char[].class)} */
1457 public static final long ARRAY_CHAR_BASE_OFFSET
1458 = theUnsafe.arrayBaseOffset(char[].class);
1459
1460 /** The value of {@code arrayBaseOffset(int[].class)} */
1461 public static final long ARRAY_INT_BASE_OFFSET
1462 = theUnsafe.arrayBaseOffset(int[].class);
1463
1464 /** The value of {@code arrayBaseOffset(long[].class)} */
1465 public static final long ARRAY_LONG_BASE_OFFSET
1466 = theUnsafe.arrayBaseOffset(long[].class);
1467
1468 /** The value of {@code arrayBaseOffset(float[].class)} */
1469 public static final long ARRAY_FLOAT_BASE_OFFSET
1470 = theUnsafe.arrayBaseOffset(float[].class);
1471
1472 /** The value of {@code arrayBaseOffset(double[].class)} */
1473 public static final long ARRAY_DOUBLE_BASE_OFFSET
1474 = theUnsafe.arrayBaseOffset(double[].class);
1475
1476 /** The value of {@code arrayBaseOffset(Object[].class)} */
1477 public static final long ARRAY_OBJECT_BASE_OFFSET
1478 = theUnsafe.arrayBaseOffset(Object[].class);
1479
1480 /**
1481 * Reports the scale factor for addressing elements in the storage
1482 * allocation of a given array class. However, arrays of "narrow" types
1483 * will generally not work properly with accessors like {@link
1484 * #getByte(Object, long)}, so the scale factor for such classes is reported
1485 * as zero.
1486 * <p>
1487 * The computation of the actual memory offset should always use {@code
1488 * long} arithmetic to avoid overflows.
1489 *
1490 * @see #arrayBaseOffset
1491 * @see #getInt(Object, long)
1492 * @see #putInt(Object, long, int)
1493 */
1494 public int arrayIndexScale(Class<?> arrayClass) {
1495 if (arrayClass == null) {
1496 throw new NullPointerException();
1497 }
1498
1499 return arrayIndexScale0(arrayClass);
1500 }
1501
1502 public int arrayIndexScale(Object[] array) {
1503 if (array == null) {
1504 throw new NullPointerException();
1505 }
1506
1507 return arrayIndexScale1(array);
1508 }
1509
1510 /**
1511 * Return the size of the object in the heap.
1512 * @param o an object
1513 * @return the objects's size
1514 * @since Valhalla
1515 */
1516 public long getObjectSize(Object o) {
1517 if (o == null)
1518 throw new NullPointerException();
1519 return getObjectSize0(o);
1520 }
1521
1522 /** The value of {@code arrayIndexScale(boolean[].class)} */
1523 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1524 = theUnsafe.arrayIndexScale(boolean[].class);
1525
1526 /** The value of {@code arrayIndexScale(byte[].class)} */
1527 public static final int ARRAY_BYTE_INDEX_SCALE
1528 = theUnsafe.arrayIndexScale(byte[].class);
1529
1530 /** The value of {@code arrayIndexScale(short[].class)} */
1531 public static final int ARRAY_SHORT_INDEX_SCALE
1532 = theUnsafe.arrayIndexScale(short[].class);
1533
1534 /** The value of {@code arrayIndexScale(char[].class)} */
1535 public static final int ARRAY_CHAR_INDEX_SCALE
1536 = theUnsafe.arrayIndexScale(char[].class);
1537
1538 /** The value of {@code arrayIndexScale(int[].class)} */
1539 public static final int ARRAY_INT_INDEX_SCALE
1540 = theUnsafe.arrayIndexScale(int[].class);
1541
1542 /** The value of {@code arrayIndexScale(long[].class)} */
1543 public static final int ARRAY_LONG_INDEX_SCALE
1544 = theUnsafe.arrayIndexScale(long[].class);
1545
1546 /** The value of {@code arrayIndexScale(float[].class)} */
1547 public static final int ARRAY_FLOAT_INDEX_SCALE
1548 = theUnsafe.arrayIndexScale(float[].class);
1549
1550 /** The value of {@code arrayIndexScale(double[].class)} */
1551 public static final int ARRAY_DOUBLE_INDEX_SCALE
1552 = theUnsafe.arrayIndexScale(double[].class);
1553
1554 /** The value of {@code arrayIndexScale(Object[].class)} */
1555 public static final int ARRAY_OBJECT_INDEX_SCALE
1556 = theUnsafe.arrayIndexScale(Object[].class);
1557
1558 /**
1559 * Reports the size in bytes of a native pointer, as stored via {@link
1560 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1561 * other primitive types (as stored in native memory blocks) is determined
1562 * fully by their information content.
1563 */
1564 public int addressSize() {
1565 return ADDRESS_SIZE;
1566 }
1567
1568 /** The value of {@code addressSize()} */
1569 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1570
1571 /**
1572 * Reports the size in bytes of a native memory page (whatever that is).
1573 * This value will always be a power of two.
1574 */
1575 public int pageSize() { return PAGE_SIZE; }
1576
1577 /**
1578 * Reports the size in bytes of a data cache line written back by
1579 * the hardware cache line flush operation available to the JVM or
1580 * 0 if data cache line flushing is not enabled.
1581 */
1582 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1583
1584 /**
1585 * Rounds down address to a data cache line boundary as
1586 * determined by {@link #dataCacheLineFlushSize}
1587 * @return the rounded down address
1588 */
1589 public long dataCacheLineAlignDown(long address) {
1590 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1591 }
1592
1593 /**
1594 * Returns true if data cache line writeback
1595 */
1596 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1597
1598 //--- random trusted operations from JNI:
1599
1600 /**
1601 * Tells the VM to define a class, without security checks. By default, the
1602 * class loader and protection domain come from the caller's class.
1603 */
1604 public Class<?> defineClass(String name, byte[] b, int off, int len,
1605 ClassLoader loader,
1606 ProtectionDomain protectionDomain) {
1607 if (b == null) {
1608 throw new NullPointerException();
1609 }
1610 if (len < 0) {
1611 throw new ArrayIndexOutOfBoundsException();
1612 }
1613
1614 return defineClass0(name, b, off, len, loader, protectionDomain);
1615 }
1616
1617 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1618 ClassLoader loader,
1619 ProtectionDomain protectionDomain);
1620
1621 /**
1622 * Allocates an instance but does not run any constructor.
1623 * Initializes the class if it has not yet been.
1624 */
1625 @IntrinsicCandidate
1626 public native Object allocateInstance(Class<?> cls)
1627 throws InstantiationException;
1628
1629 /**
1630 * Allocates an array of a given type, but does not do zeroing.
1631 * <p>
1632 * This method should only be used in the very rare cases where a high-performance code
1633 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1634 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1635 * <p>
1636 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1637 * before allowing untrusted code, or code in other threads, to observe the reference
1638 * to the newly allocated array. In addition, the publication of the array reference must be
1639 * safe according to the Java Memory Model requirements.
1640 * <p>
1641 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1642 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1643 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1644 * or issuing a {@link #storeFence} before publishing the reference.
1645 * <p>
1646 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1647 * elements that could break heap integrity.
1648 *
1649 * @param componentType array component type to allocate
1650 * @param length array size to allocate
1651 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1652 * or the length is negative
1653 */
1654 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1655 if (componentType == null) {
1656 throw new IllegalArgumentException("Component type is null");
1657 }
1658 if (!componentType.isPrimitive()) {
1659 throw new IllegalArgumentException("Component type is not primitive");
1660 }
1661 if (length < 0) {
1662 throw new IllegalArgumentException("Negative length");
1663 }
1664 return allocateUninitializedArray0(componentType, length);
1665 }
1666
1667 @IntrinsicCandidate
1668 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1669 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1670 // return the zeroed arrays.
1671 if (componentType == byte.class) return new byte[length];
1672 if (componentType == boolean.class) return new boolean[length];
1673 if (componentType == short.class) return new short[length];
1674 if (componentType == char.class) return new char[length];
1675 if (componentType == int.class) return new int[length];
1676 if (componentType == float.class) return new float[length];
1677 if (componentType == long.class) return new long[length];
1678 if (componentType == double.class) return new double[length];
1679 return null;
1680 }
1681
1682 /** Throws the exception without telling the verifier. */
1683 public native void throwException(Throwable ee);
1684
1685 /**
1686 * Atomically updates Java variable to {@code x} if it is currently
1687 * holding {@code expected}.
1688 *
1689 * <p>This operation has memory semantics of a {@code volatile} read
1690 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1691 *
1692 * @return {@code true} if successful
1693 */
1694 @IntrinsicCandidate
1695 public final native boolean compareAndSetReference(Object o, long offset,
1696 Object expected,
1697 Object x);
1698
1699 private final boolean isValueObject(Object o) {
1700 return o != null && o.getClass().isValue();
1701 }
1702
1703 /*
1704 * For value type, CAS should do substitutability test as opposed
1705 * to two pointers comparison.
1706 */
1707 @ForceInline
1708 public final <V> boolean compareAndSetReference(Object o, long offset,
1709 Class<?> type,
1710 V expected,
1711 V x) {
1712 if (type.isValue() || isValueObject(expected)) {
1713 while (true) {
1714 Object witness = getReferenceVolatile(o, offset);
1715 if (witness != expected) {
1716 return false;
1717 }
1718 if (compareAndSetReference(o, offset, witness, x)) {
1719 return true;
1720 }
1721 }
1722 } else {
1723 return compareAndSetReference(o, offset, expected, x);
1724 }
1725 }
1726
1727 @ForceInline
1728 public final <V> boolean compareAndSetFlatValue(Object o, long offset,
1729 int layout,
1730 Class<?> valueType,
1731 V expected,
1732 V x) {
1733 while (true) {
1734 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1735 if (witness != expected) {
1736 return false;
1737 }
1738 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1739 return true;
1740 }
1741 }
1742 }
1743
1744 @IntrinsicCandidate
1745 public final native Object compareAndExchangeReference(Object o, long offset,
1746 Object expected,
1747 Object x);
1748
1749 @ForceInline
1750 public final <V> Object compareAndExchangeReference(Object o, long offset,
1751 Class<?> valueType,
1752 V expected,
1753 V x) {
1754 if (valueType.isValue() || isValueObject(expected)) {
1755 while (true) {
1756 Object witness = getReferenceVolatile(o, offset);
1757 if (witness != expected) {
1758 return witness;
1759 }
1760 if (compareAndSetReference(o, offset, witness, x)) {
1761 return witness;
1762 }
1763 }
1764 } else {
1765 return compareAndExchangeReference(o, offset, expected, x);
1766 }
1767 }
1768
1769 @ForceInline
1770 public final <V> Object compareAndExchangeFlatValue(Object o, long offset,
1771 int layout,
1772 Class<?> valueType,
1773 V expected,
1774 V x) {
1775 while (true) {
1776 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1777 if (witness != expected) {
1778 return witness;
1779 }
1780 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1781 return witness;
1782 }
1783 }
1784 }
1785
1786 @IntrinsicCandidate
1787 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1788 Object expected,
1789 Object x) {
1790 return compareAndExchangeReference(o, offset, expected, x);
1791 }
1792
1793 public final <V> Object compareAndExchangeReferenceAcquire(Object o, long offset,
1794 Class<?> valueType,
1795 V expected,
1796 V x) {
1797 return compareAndExchangeReference(o, offset, valueType, expected, x);
1798 }
1799
1800 @ForceInline
1801 public final <V> Object compareAndExchangeFlatValueAcquire(Object o, long offset,
1802 int layout,
1803 Class<?> valueType,
1804 V expected,
1805 V x) {
1806 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1807 }
1808
1809 @IntrinsicCandidate
1810 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1811 Object expected,
1812 Object x) {
1813 return compareAndExchangeReference(o, offset, expected, x);
1814 }
1815
1816 public final <V> Object compareAndExchangeReferenceRelease(Object o, long offset,
1817 Class<?> valueType,
1818 V expected,
1819 V x) {
1820 return compareAndExchangeReference(o, offset, valueType, expected, x);
1821 }
1822
1823 @ForceInline
1824 public final <V> Object compareAndExchangeFlatValueRelease(Object o, long offset,
1825 int layout,
1826 Class<?> valueType,
1827 V expected,
1828 V x) {
1829 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1830 }
1831
1832 @IntrinsicCandidate
1833 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1834 Object expected,
1835 Object x) {
1836 return compareAndSetReference(o, offset, expected, x);
1837 }
1838
1839 public final <V> boolean weakCompareAndSetReferencePlain(Object o, long offset,
1840 Class<?> valueType,
1841 V expected,
1842 V x) {
1843 if (valueType.isValue() || isValueObject(expected)) {
1844 return compareAndSetReference(o, offset, valueType, expected, x);
1845 } else {
1846 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1847 }
1848 }
1849
1850 @ForceInline
1851 public final <V> boolean weakCompareAndSetFlatValuePlain(Object o, long offset,
1852 int layout,
1853 Class<?> valueType,
1854 V expected,
1855 V x) {
1856 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1857 }
1858
1859 @IntrinsicCandidate
1860 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1861 Object expected,
1862 Object x) {
1863 return compareAndSetReference(o, offset, expected, x);
1864 }
1865
1866 public final <V> boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1867 Class<?> valueType,
1868 V expected,
1869 V x) {
1870 if (valueType.isValue() || isValueObject(expected)) {
1871 return compareAndSetReference(o, offset, valueType, expected, x);
1872 } else {
1873 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1874 }
1875 }
1876
1877 @ForceInline
1878 public final <V> boolean weakCompareAndSetFlatValueAcquire(Object o, long offset,
1879 int layout,
1880 Class<?> valueType,
1881 V expected,
1882 V x) {
1883 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1884 }
1885
1886 @IntrinsicCandidate
1887 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1888 Object expected,
1889 Object x) {
1890 return compareAndSetReference(o, offset, expected, x);
1891 }
1892
1893 public final <V> boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1894 Class<?> valueType,
1895 V expected,
1896 V x) {
1897 if (valueType.isValue() || isValueObject(expected)) {
1898 return compareAndSetReference(o, offset, valueType, expected, x);
1899 } else {
1900 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1901 }
1902 }
1903
1904 @ForceInline
1905 public final <V> boolean weakCompareAndSetFlatValueRelease(Object o, long offset,
1906 int layout,
1907 Class<?> valueType,
1908 V expected,
1909 V x) {
1910 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1911 }
1912
1913 @IntrinsicCandidate
1914 public final boolean weakCompareAndSetReference(Object o, long offset,
1915 Object expected,
1916 Object x) {
1917 return compareAndSetReference(o, offset, expected, x);
1918 }
1919
1920 public final <V> boolean weakCompareAndSetReference(Object o, long offset,
1921 Class<?> valueType,
1922 V expected,
1923 V x) {
1924 if (valueType.isValue() || isValueObject(expected)) {
1925 return compareAndSetReference(o, offset, valueType, expected, x);
1926 } else {
1927 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1928 }
1929 }
1930
1931 @ForceInline
1932 public final <V> boolean weakCompareAndSetFlatValue(Object o, long offset,
1933 int layout,
1934 Class<?> valueType,
1935 V expected,
1936 V x) {
1937 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1938 }
1939
1940 /**
1941 * Atomically updates Java variable to {@code x} if it is currently
1942 * holding {@code expected}.
1943 *
1944 * <p>This operation has memory semantics of a {@code volatile} read
1945 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1946 *
1947 * @return {@code true} if successful
1948 */
1949 @IntrinsicCandidate
1950 public final native boolean compareAndSetInt(Object o, long offset,
1951 int expected,
1952 int x);
1953
1954 @IntrinsicCandidate
1955 public final native int compareAndExchangeInt(Object o, long offset,
1956 int expected,
1957 int x);
1958
1959 @IntrinsicCandidate
1960 public final int compareAndExchangeIntAcquire(Object o, long offset,
1961 int expected,
1962 int x) {
1963 return compareAndExchangeInt(o, offset, expected, x);
1964 }
1965
1966 @IntrinsicCandidate
1967 public final int compareAndExchangeIntRelease(Object o, long offset,
1968 int expected,
1969 int x) {
1970 return compareAndExchangeInt(o, offset, expected, x);
1971 }
1972
1973 @IntrinsicCandidate
1974 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1975 int expected,
1976 int x) {
1977 return compareAndSetInt(o, offset, expected, x);
1978 }
1979
1980 @IntrinsicCandidate
1981 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1982 int expected,
1983 int x) {
1984 return compareAndSetInt(o, offset, expected, x);
1985 }
1986
1987 @IntrinsicCandidate
1988 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1989 int expected,
1990 int x) {
1991 return compareAndSetInt(o, offset, expected, x);
1992 }
1993
1994 @IntrinsicCandidate
1995 public final boolean weakCompareAndSetInt(Object o, long offset,
1996 int expected,
1997 int x) {
1998 return compareAndSetInt(o, offset, expected, x);
1999 }
2000
2001 @IntrinsicCandidate
2002 public final byte compareAndExchangeByte(Object o, long offset,
2003 byte expected,
2004 byte x) {
2005 long wordOffset = offset & ~3;
2006 int shift = (int) (offset & 3) << 3;
2007 if (BIG_ENDIAN) {
2008 shift = 24 - shift;
2009 }
2010 int mask = 0xFF << shift;
2011 int maskedExpected = (expected & 0xFF) << shift;
2012 int maskedX = (x & 0xFF) << shift;
2013 int fullWord;
2014 do {
2015 fullWord = getIntVolatile(o, wordOffset);
2016 if ((fullWord & mask) != maskedExpected)
2017 return (byte) ((fullWord & mask) >> shift);
2018 } while (!weakCompareAndSetInt(o, wordOffset,
2019 fullWord, (fullWord & ~mask) | maskedX));
2020 return expected;
2021 }
2022
2023 @IntrinsicCandidate
2024 public final boolean compareAndSetByte(Object o, long offset,
2025 byte expected,
2026 byte x) {
2027 return compareAndExchangeByte(o, offset, expected, x) == expected;
2028 }
2029
2030 @IntrinsicCandidate
2031 public final boolean weakCompareAndSetByte(Object o, long offset,
2032 byte expected,
2033 byte x) {
2034 return compareAndSetByte(o, offset, expected, x);
2035 }
2036
2037 @IntrinsicCandidate
2038 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
2039 byte expected,
2040 byte x) {
2041 return weakCompareAndSetByte(o, offset, expected, x);
2042 }
2043
2044 @IntrinsicCandidate
2045 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
2046 byte expected,
2047 byte x) {
2048 return weakCompareAndSetByte(o, offset, expected, x);
2049 }
2050
2051 @IntrinsicCandidate
2052 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
2053 byte expected,
2054 byte x) {
2055 return weakCompareAndSetByte(o, offset, expected, x);
2056 }
2057
2058 @IntrinsicCandidate
2059 public final byte compareAndExchangeByteAcquire(Object o, long offset,
2060 byte expected,
2061 byte x) {
2062 return compareAndExchangeByte(o, offset, expected, x);
2063 }
2064
2065 @IntrinsicCandidate
2066 public final byte compareAndExchangeByteRelease(Object o, long offset,
2067 byte expected,
2068 byte x) {
2069 return compareAndExchangeByte(o, offset, expected, x);
2070 }
2071
2072 @IntrinsicCandidate
2073 public final short compareAndExchangeShort(Object o, long offset,
2074 short expected,
2075 short x) {
2076 if ((offset & 3) == 3) {
2077 throw new IllegalArgumentException("Update spans the word, not supported");
2078 }
2079 long wordOffset = offset & ~3;
2080 int shift = (int) (offset & 3) << 3;
2081 if (BIG_ENDIAN) {
2082 shift = 16 - shift;
2083 }
2084 int mask = 0xFFFF << shift;
2085 int maskedExpected = (expected & 0xFFFF) << shift;
2086 int maskedX = (x & 0xFFFF) << shift;
2087 int fullWord;
2088 do {
2089 fullWord = getIntVolatile(o, wordOffset);
2090 if ((fullWord & mask) != maskedExpected) {
2091 return (short) ((fullWord & mask) >> shift);
2092 }
2093 } while (!weakCompareAndSetInt(o, wordOffset,
2094 fullWord, (fullWord & ~mask) | maskedX));
2095 return expected;
2096 }
2097
2098 @IntrinsicCandidate
2099 public final boolean compareAndSetShort(Object o, long offset,
2100 short expected,
2101 short x) {
2102 return compareAndExchangeShort(o, offset, expected, x) == expected;
2103 }
2104
2105 @IntrinsicCandidate
2106 public final boolean weakCompareAndSetShort(Object o, long offset,
2107 short expected,
2108 short x) {
2109 return compareAndSetShort(o, offset, expected, x);
2110 }
2111
2112 @IntrinsicCandidate
2113 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
2114 short expected,
2115 short x) {
2116 return weakCompareAndSetShort(o, offset, expected, x);
2117 }
2118
2119 @IntrinsicCandidate
2120 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
2121 short expected,
2122 short x) {
2123 return weakCompareAndSetShort(o, offset, expected, x);
2124 }
2125
2126 @IntrinsicCandidate
2127 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
2128 short expected,
2129 short x) {
2130 return weakCompareAndSetShort(o, offset, expected, x);
2131 }
2132
2133
2134 @IntrinsicCandidate
2135 public final short compareAndExchangeShortAcquire(Object o, long offset,
2136 short expected,
2137 short x) {
2138 return compareAndExchangeShort(o, offset, expected, x);
2139 }
2140
2141 @IntrinsicCandidate
2142 public final short compareAndExchangeShortRelease(Object o, long offset,
2143 short expected,
2144 short x) {
2145 return compareAndExchangeShort(o, offset, expected, x);
2146 }
2147
2148 @ForceInline
2149 private char s2c(short s) {
2150 return (char) s;
2151 }
2152
2153 @ForceInline
2154 private short c2s(char s) {
2155 return (short) s;
2156 }
2157
2158 @ForceInline
2159 public final boolean compareAndSetChar(Object o, long offset,
2160 char expected,
2161 char x) {
2162 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
2163 }
2164
2165 @ForceInline
2166 public final char compareAndExchangeChar(Object o, long offset,
2167 char expected,
2168 char x) {
2169 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
2170 }
2171
2172 @ForceInline
2173 public final char compareAndExchangeCharAcquire(Object o, long offset,
2174 char expected,
2175 char x) {
2176 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
2177 }
2178
2179 @ForceInline
2180 public final char compareAndExchangeCharRelease(Object o, long offset,
2181 char expected,
2182 char x) {
2183 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
2184 }
2185
2186 @ForceInline
2187 public final boolean weakCompareAndSetChar(Object o, long offset,
2188 char expected,
2189 char x) {
2190 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
2191 }
2192
2193 @ForceInline
2194 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
2195 char expected,
2196 char x) {
2197 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
2198 }
2199
2200 @ForceInline
2201 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
2202 char expected,
2203 char x) {
2204 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
2205 }
2206
2207 @ForceInline
2208 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
2209 char expected,
2210 char x) {
2211 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
2212 }
2213
2214 /**
2215 * The JVM converts integral values to boolean values using two
2216 * different conventions, byte testing against zero and truncation
2217 * to least-significant bit.
2218 *
2219 * <p>The JNI documents specify that, at least for returning
2220 * values from native methods, a Java boolean value is converted
2221 * to the value-set 0..1 by first truncating to a byte (0..255 or
2222 * maybe -128..127) and then testing against zero. Thus, Java
2223 * booleans in non-Java data structures are by convention
2224 * represented as 8-bit containers containing either zero (for
2225 * false) or any non-zero value (for true).
2226 *
2227 * <p>Java booleans in the heap are also stored in bytes, but are
2228 * strongly normalized to the value-set 0..1 (i.e., they are
2229 * truncated to the least-significant bit).
2230 *
2231 * <p>The main reason for having different conventions for
2232 * conversion is performance: Truncation to the least-significant
2233 * bit can be usually implemented with fewer (machine)
2234 * instructions than byte testing against zero.
2235 *
2236 * <p>A number of Unsafe methods load boolean values from the heap
2237 * as bytes. Unsafe converts those values according to the JNI
2238 * rules (i.e, using the "testing against zero" convention). The
2239 * method {@code byte2bool} implements that conversion.
2240 *
2241 * @param b the byte to be converted to boolean
2242 * @return the result of the conversion
2243 */
2244 @ForceInline
2245 private boolean byte2bool(byte b) {
2246 return b != 0;
2247 }
2248
2249 /**
2250 * Convert a boolean value to a byte. The return value is strongly
2251 * normalized to the value-set 0..1 (i.e., the value is truncated
2252 * to the least-significant bit). See {@link #byte2bool(byte)} for
2253 * more details on conversion conventions.
2254 *
2255 * @param b the boolean to be converted to byte (and then normalized)
2256 * @return the result of the conversion
2257 */
2258 @ForceInline
2259 private byte bool2byte(boolean b) {
2260 return b ? (byte)1 : (byte)0;
2261 }
2262
2263 @ForceInline
2264 public final boolean compareAndSetBoolean(Object o, long offset,
2265 boolean expected,
2266 boolean x) {
2267 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2268 }
2269
2270 @ForceInline
2271 public final boolean compareAndExchangeBoolean(Object o, long offset,
2272 boolean expected,
2273 boolean x) {
2274 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
2275 }
2276
2277 @ForceInline
2278 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
2279 boolean expected,
2280 boolean x) {
2281 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
2282 }
2283
2284 @ForceInline
2285 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
2286 boolean expected,
2287 boolean x) {
2288 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
2289 }
2290
2291 @ForceInline
2292 public final boolean weakCompareAndSetBoolean(Object o, long offset,
2293 boolean expected,
2294 boolean x) {
2295 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2296 }
2297
2298 @ForceInline
2299 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
2300 boolean expected,
2301 boolean x) {
2302 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
2303 }
2304
2305 @ForceInline
2306 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
2307 boolean expected,
2308 boolean x) {
2309 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
2310 }
2311
2312 @ForceInline
2313 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
2314 boolean expected,
2315 boolean x) {
2316 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
2317 }
2318
2319 /**
2320 * Atomically updates Java variable to {@code x} if it is currently
2321 * holding {@code expected}.
2322 *
2323 * <p>This operation has memory semantics of a {@code volatile} read
2324 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2325 *
2326 * @return {@code true} if successful
2327 */
2328 @ForceInline
2329 public final boolean compareAndSetFloat(Object o, long offset,
2330 float expected,
2331 float x) {
2332 return compareAndSetInt(o, offset,
2333 Float.floatToRawIntBits(expected),
2334 Float.floatToRawIntBits(x));
2335 }
2336
2337 @ForceInline
2338 public final float compareAndExchangeFloat(Object o, long offset,
2339 float expected,
2340 float x) {
2341 int w = compareAndExchangeInt(o, offset,
2342 Float.floatToRawIntBits(expected),
2343 Float.floatToRawIntBits(x));
2344 return Float.intBitsToFloat(w);
2345 }
2346
2347 @ForceInline
2348 public final float compareAndExchangeFloatAcquire(Object o, long offset,
2349 float expected,
2350 float x) {
2351 int w = compareAndExchangeIntAcquire(o, offset,
2352 Float.floatToRawIntBits(expected),
2353 Float.floatToRawIntBits(x));
2354 return Float.intBitsToFloat(w);
2355 }
2356
2357 @ForceInline
2358 public final float compareAndExchangeFloatRelease(Object o, long offset,
2359 float expected,
2360 float x) {
2361 int w = compareAndExchangeIntRelease(o, offset,
2362 Float.floatToRawIntBits(expected),
2363 Float.floatToRawIntBits(x));
2364 return Float.intBitsToFloat(w);
2365 }
2366
2367 @ForceInline
2368 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
2369 float expected,
2370 float x) {
2371 return weakCompareAndSetIntPlain(o, offset,
2372 Float.floatToRawIntBits(expected),
2373 Float.floatToRawIntBits(x));
2374 }
2375
2376 @ForceInline
2377 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
2378 float expected,
2379 float x) {
2380 return weakCompareAndSetIntAcquire(o, offset,
2381 Float.floatToRawIntBits(expected),
2382 Float.floatToRawIntBits(x));
2383 }
2384
2385 @ForceInline
2386 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
2387 float expected,
2388 float x) {
2389 return weakCompareAndSetIntRelease(o, offset,
2390 Float.floatToRawIntBits(expected),
2391 Float.floatToRawIntBits(x));
2392 }
2393
2394 @ForceInline
2395 public final boolean weakCompareAndSetFloat(Object o, long offset,
2396 float expected,
2397 float x) {
2398 return weakCompareAndSetInt(o, offset,
2399 Float.floatToRawIntBits(expected),
2400 Float.floatToRawIntBits(x));
2401 }
2402
2403 /**
2404 * Atomically updates Java variable to {@code x} if it is currently
2405 * holding {@code expected}.
2406 *
2407 * <p>This operation has memory semantics of a {@code volatile} read
2408 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2409 *
2410 * @return {@code true} if successful
2411 */
2412 @ForceInline
2413 public final boolean compareAndSetDouble(Object o, long offset,
2414 double expected,
2415 double x) {
2416 return compareAndSetLong(o, offset,
2417 Double.doubleToRawLongBits(expected),
2418 Double.doubleToRawLongBits(x));
2419 }
2420
2421 @ForceInline
2422 public final double compareAndExchangeDouble(Object o, long offset,
2423 double expected,
2424 double x) {
2425 long w = compareAndExchangeLong(o, offset,
2426 Double.doubleToRawLongBits(expected),
2427 Double.doubleToRawLongBits(x));
2428 return Double.longBitsToDouble(w);
2429 }
2430
2431 @ForceInline
2432 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
2433 double expected,
2434 double x) {
2435 long w = compareAndExchangeLongAcquire(o, offset,
2436 Double.doubleToRawLongBits(expected),
2437 Double.doubleToRawLongBits(x));
2438 return Double.longBitsToDouble(w);
2439 }
2440
2441 @ForceInline
2442 public final double compareAndExchangeDoubleRelease(Object o, long offset,
2443 double expected,
2444 double x) {
2445 long w = compareAndExchangeLongRelease(o, offset,
2446 Double.doubleToRawLongBits(expected),
2447 Double.doubleToRawLongBits(x));
2448 return Double.longBitsToDouble(w);
2449 }
2450
2451 @ForceInline
2452 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
2453 double expected,
2454 double x) {
2455 return weakCompareAndSetLongPlain(o, offset,
2456 Double.doubleToRawLongBits(expected),
2457 Double.doubleToRawLongBits(x));
2458 }
2459
2460 @ForceInline
2461 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2462 double expected,
2463 double x) {
2464 return weakCompareAndSetLongAcquire(o, offset,
2465 Double.doubleToRawLongBits(expected),
2466 Double.doubleToRawLongBits(x));
2467 }
2468
2469 @ForceInline
2470 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2471 double expected,
2472 double x) {
2473 return weakCompareAndSetLongRelease(o, offset,
2474 Double.doubleToRawLongBits(expected),
2475 Double.doubleToRawLongBits(x));
2476 }
2477
2478 @ForceInline
2479 public final boolean weakCompareAndSetDouble(Object o, long offset,
2480 double expected,
2481 double x) {
2482 return weakCompareAndSetLong(o, offset,
2483 Double.doubleToRawLongBits(expected),
2484 Double.doubleToRawLongBits(x));
2485 }
2486
2487 /**
2488 * Atomically updates Java variable to {@code x} if it is currently
2489 * holding {@code expected}.
2490 *
2491 * <p>This operation has memory semantics of a {@code volatile} read
2492 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2493 *
2494 * @return {@code true} if successful
2495 */
2496 @IntrinsicCandidate
2497 public final native boolean compareAndSetLong(Object o, long offset,
2498 long expected,
2499 long x);
2500
2501 @IntrinsicCandidate
2502 public final native long compareAndExchangeLong(Object o, long offset,
2503 long expected,
2504 long x);
2505
2506 @IntrinsicCandidate
2507 public final long compareAndExchangeLongAcquire(Object o, long offset,
2508 long expected,
2509 long x) {
2510 return compareAndExchangeLong(o, offset, expected, x);
2511 }
2512
2513 @IntrinsicCandidate
2514 public final long compareAndExchangeLongRelease(Object o, long offset,
2515 long expected,
2516 long x) {
2517 return compareAndExchangeLong(o, offset, expected, x);
2518 }
2519
2520 @IntrinsicCandidate
2521 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2522 long expected,
2523 long x) {
2524 return compareAndSetLong(o, offset, expected, x);
2525 }
2526
2527 @IntrinsicCandidate
2528 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2529 long expected,
2530 long x) {
2531 return compareAndSetLong(o, offset, expected, x);
2532 }
2533
2534 @IntrinsicCandidate
2535 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2536 long expected,
2537 long x) {
2538 return compareAndSetLong(o, offset, expected, x);
2539 }
2540
2541 @IntrinsicCandidate
2542 public final boolean weakCompareAndSetLong(Object o, long offset,
2543 long expected,
2544 long x) {
2545 return compareAndSetLong(o, offset, expected, x);
2546 }
2547
2548 /**
2549 * Fetches a reference value from a given Java variable, with volatile
2550 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2551 */
2552 @IntrinsicCandidate
2553 public native Object getReferenceVolatile(Object o, long offset);
2554
2555 @ForceInline
2556 public final <V> Object getFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType) {
2557 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2558 Object res = getFlatValue(o, offset, layout, valueType);
2559 fullFence();
2560 return res;
2561 }
2562
2563 /**
2564 * Stores a reference value into a given Java variable, with
2565 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2566 */
2567 @IntrinsicCandidate
2568 public native void putReferenceVolatile(Object o, long offset, Object x);
2569
2570 @ForceInline
2571 public final <V> void putFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType, V x) {
2572 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2573 putFlatValueRelease(o, offset, layout, valueType, x);
2574 fullFence();
2575 }
2576
2577 /** Volatile version of {@link #getInt(Object, long)} */
2578 @IntrinsicCandidate
2579 public native int getIntVolatile(Object o, long offset);
2580
2581 /** Volatile version of {@link #putInt(Object, long, int)} */
2582 @IntrinsicCandidate
2583 public native void putIntVolatile(Object o, long offset, int x);
2584
2585 /** Volatile version of {@link #getBoolean(Object, long)} */
2586 @IntrinsicCandidate
2587 public native boolean getBooleanVolatile(Object o, long offset);
2588
2589 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2590 @IntrinsicCandidate
2591 public native void putBooleanVolatile(Object o, long offset, boolean x);
2592
2593 /** Volatile version of {@link #getByte(Object, long)} */
2594 @IntrinsicCandidate
2595 public native byte getByteVolatile(Object o, long offset);
2596
2597 /** Volatile version of {@link #putByte(Object, long, byte)} */
2598 @IntrinsicCandidate
2599 public native void putByteVolatile(Object o, long offset, byte x);
2600
2601 /** Volatile version of {@link #getShort(Object, long)} */
2602 @IntrinsicCandidate
2603 public native short getShortVolatile(Object o, long offset);
2604
2605 /** Volatile version of {@link #putShort(Object, long, short)} */
2606 @IntrinsicCandidate
2607 public native void putShortVolatile(Object o, long offset, short x);
2608
2609 /** Volatile version of {@link #getChar(Object, long)} */
2610 @IntrinsicCandidate
2611 public native char getCharVolatile(Object o, long offset);
2612
2613 /** Volatile version of {@link #putChar(Object, long, char)} */
2614 @IntrinsicCandidate
2615 public native void putCharVolatile(Object o, long offset, char x);
2616
2617 /** Volatile version of {@link #getLong(Object, long)} */
2618 @IntrinsicCandidate
2619 public native long getLongVolatile(Object o, long offset);
2620
2621 /** Volatile version of {@link #putLong(Object, long, long)} */
2622 @IntrinsicCandidate
2623 public native void putLongVolatile(Object o, long offset, long x);
2624
2625 /** Volatile version of {@link #getFloat(Object, long)} */
2626 @IntrinsicCandidate
2627 public native float getFloatVolatile(Object o, long offset);
2628
2629 /** Volatile version of {@link #putFloat(Object, long, float)} */
2630 @IntrinsicCandidate
2631 public native void putFloatVolatile(Object o, long offset, float x);
2632
2633 /** Volatile version of {@link #getDouble(Object, long)} */
2634 @IntrinsicCandidate
2635 public native double getDoubleVolatile(Object o, long offset);
2636
2637 /** Volatile version of {@link #putDouble(Object, long, double)} */
2638 @IntrinsicCandidate
2639 public native void putDoubleVolatile(Object o, long offset, double x);
2640
2641
2642
2643 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2644 @IntrinsicCandidate
2645 public final Object getReferenceAcquire(Object o, long offset) {
2646 return getReferenceVolatile(o, offset);
2647 }
2648
2649 @ForceInline
2650 public final <V> Object getFlatValueAcquire(Object o, long offset, int layout, Class<?> valueType) {
2651 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2652 Object res = getFlatValue(o, offset, layout, valueType);
2653 loadFence();
2654 return res;
2655 }
2656
2657 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2658 @IntrinsicCandidate
2659 public final boolean getBooleanAcquire(Object o, long offset) {
2660 return getBooleanVolatile(o, offset);
2661 }
2662
2663 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2664 @IntrinsicCandidate
2665 public final byte getByteAcquire(Object o, long offset) {
2666 return getByteVolatile(o, offset);
2667 }
2668
2669 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2670 @IntrinsicCandidate
2671 public final short getShortAcquire(Object o, long offset) {
2672 return getShortVolatile(o, offset);
2673 }
2674
2675 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2676 @IntrinsicCandidate
2677 public final char getCharAcquire(Object o, long offset) {
2678 return getCharVolatile(o, offset);
2679 }
2680
2681 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2682 @IntrinsicCandidate
2683 public final int getIntAcquire(Object o, long offset) {
2684 return getIntVolatile(o, offset);
2685 }
2686
2687 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2688 @IntrinsicCandidate
2689 public final float getFloatAcquire(Object o, long offset) {
2690 return getFloatVolatile(o, offset);
2691 }
2692
2693 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2694 @IntrinsicCandidate
2695 public final long getLongAcquire(Object o, long offset) {
2696 return getLongVolatile(o, offset);
2697 }
2698
2699 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2700 @IntrinsicCandidate
2701 public final double getDoubleAcquire(Object o, long offset) {
2702 return getDoubleVolatile(o, offset);
2703 }
2704
2705 /*
2706 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2707 * that do not guarantee immediate visibility of the store to
2708 * other threads. This method is generally only useful if the
2709 * underlying field is a Java volatile (or if an array cell, one
2710 * that is otherwise only accessed using volatile accesses).
2711 *
2712 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2713 */
2714
2715 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2716 @IntrinsicCandidate
2717 public final void putReferenceRelease(Object o, long offset, Object x) {
2718 putReferenceVolatile(o, offset, x);
2719 }
2720
2721 @ForceInline
2722 public final <V> void putFlatValueRelease(Object o, long offset, int layout, Class<?> valueType, V x) {
2723 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2724 storeFence();
2725 putFlatValue(o, offset, layout, valueType, x);
2726 }
2727
2728 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2729 @IntrinsicCandidate
2730 public final void putBooleanRelease(Object o, long offset, boolean x) {
2731 putBooleanVolatile(o, offset, x);
2732 }
2733
2734 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2735 @IntrinsicCandidate
2736 public final void putByteRelease(Object o, long offset, byte x) {
2737 putByteVolatile(o, offset, x);
2738 }
2739
2740 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2741 @IntrinsicCandidate
2742 public final void putShortRelease(Object o, long offset, short x) {
2743 putShortVolatile(o, offset, x);
2744 }
2745
2746 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2747 @IntrinsicCandidate
2748 public final void putCharRelease(Object o, long offset, char x) {
2749 putCharVolatile(o, offset, x);
2750 }
2751
2752 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2753 @IntrinsicCandidate
2754 public final void putIntRelease(Object o, long offset, int x) {
2755 putIntVolatile(o, offset, x);
2756 }
2757
2758 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2759 @IntrinsicCandidate
2760 public final void putFloatRelease(Object o, long offset, float x) {
2761 putFloatVolatile(o, offset, x);
2762 }
2763
2764 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2765 @IntrinsicCandidate
2766 public final void putLongRelease(Object o, long offset, long x) {
2767 putLongVolatile(o, offset, x);
2768 }
2769
2770 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2771 @IntrinsicCandidate
2772 public final void putDoubleRelease(Object o, long offset, double x) {
2773 putDoubleVolatile(o, offset, x);
2774 }
2775
2776 // ------------------------------ Opaque --------------------------------------
2777
2778 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2779 @IntrinsicCandidate
2780 public final Object getReferenceOpaque(Object o, long offset) {
2781 return getReferenceVolatile(o, offset);
2782 }
2783
2784 @ForceInline
2785 public final <V> Object getFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType) {
2786 // this is stronger than opaque semantics
2787 return getFlatValueAcquire(o, offset, layout, valueType);
2788 }
2789
2790 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2791 @IntrinsicCandidate
2792 public final boolean getBooleanOpaque(Object o, long offset) {
2793 return getBooleanVolatile(o, offset);
2794 }
2795
2796 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2797 @IntrinsicCandidate
2798 public final byte getByteOpaque(Object o, long offset) {
2799 return getByteVolatile(o, offset);
2800 }
2801
2802 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2803 @IntrinsicCandidate
2804 public final short getShortOpaque(Object o, long offset) {
2805 return getShortVolatile(o, offset);
2806 }
2807
2808 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2809 @IntrinsicCandidate
2810 public final char getCharOpaque(Object o, long offset) {
2811 return getCharVolatile(o, offset);
2812 }
2813
2814 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2815 @IntrinsicCandidate
2816 public final int getIntOpaque(Object o, long offset) {
2817 return getIntVolatile(o, offset);
2818 }
2819
2820 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2821 @IntrinsicCandidate
2822 public final float getFloatOpaque(Object o, long offset) {
2823 return getFloatVolatile(o, offset);
2824 }
2825
2826 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2827 @IntrinsicCandidate
2828 public final long getLongOpaque(Object o, long offset) {
2829 return getLongVolatile(o, offset);
2830 }
2831
2832 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2833 @IntrinsicCandidate
2834 public final double getDoubleOpaque(Object o, long offset) {
2835 return getDoubleVolatile(o, offset);
2836 }
2837
2838 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2839 @IntrinsicCandidate
2840 public final void putReferenceOpaque(Object o, long offset, Object x) {
2841 putReferenceVolatile(o, offset, x);
2842 }
2843
2844 @ForceInline
2845 public final <V> void putFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType, V x) {
2846 // this is stronger than opaque semantics
2847 putFlatValueRelease(o, offset, layout, valueType, x);
2848 }
2849
2850 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2851 @IntrinsicCandidate
2852 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2853 putBooleanVolatile(o, offset, x);
2854 }
2855
2856 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2857 @IntrinsicCandidate
2858 public final void putByteOpaque(Object o, long offset, byte x) {
2859 putByteVolatile(o, offset, x);
2860 }
2861
2862 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2863 @IntrinsicCandidate
2864 public final void putShortOpaque(Object o, long offset, short x) {
2865 putShortVolatile(o, offset, x);
2866 }
2867
2868 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2869 @IntrinsicCandidate
2870 public final void putCharOpaque(Object o, long offset, char x) {
2871 putCharVolatile(o, offset, x);
2872 }
2873
2874 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2875 @IntrinsicCandidate
2876 public final void putIntOpaque(Object o, long offset, int x) {
2877 putIntVolatile(o, offset, x);
2878 }
2879
2880 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2881 @IntrinsicCandidate
2882 public final void putFloatOpaque(Object o, long offset, float x) {
2883 putFloatVolatile(o, offset, x);
2884 }
2885
2886 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2887 @IntrinsicCandidate
2888 public final void putLongOpaque(Object o, long offset, long x) {
2889 putLongVolatile(o, offset, x);
2890 }
2891
2892 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2893 @IntrinsicCandidate
2894 public final void putDoubleOpaque(Object o, long offset, double x) {
2895 putDoubleVolatile(o, offset, x);
2896 }
2897
2898 @ForceInline
2899 private boolean compareAndSetFlatValueAsBytes(Object o, long offset, int layout, Class<?> valueType, Object expected, Object x) {
2900 // We turn the payload of an atomic value into a numeric value (of suitable type)
2901 // by storing the value into an array element (of matching layout) and by reading
2902 // back the array element as an integral value. After which we can implement the CAS
2903 // as a plain numeric CAS. Note: this only works if the payload contains no oops
2904 // (see VarHandles::isAtomicFlat).
2905 Object[] expectedArray = newSpecialArray(valueType, 1, layout);
2906 Object xArray = newSpecialArray(valueType, 1, layout);
2907 long base = arrayBaseOffset(expectedArray);
2908 int scale = arrayIndexScale(expectedArray);
2909 putFlatValue(expectedArray, base, layout, valueType, expected);
2910 putFlatValue(xArray, base, layout, valueType, x);
2911 switch (scale) {
2912 case 1: {
2913 byte expectedByte = getByte(expectedArray, base);
2914 byte xByte = getByte(xArray, base);
2915 return compareAndSetByte(o, offset, expectedByte, xByte);
2916 }
2917 case 2: {
2918 short expectedShort = getShort(expectedArray, base);
2919 short xShort = getShort(xArray, base);
2920 return compareAndSetShort(o, offset, expectedShort, xShort);
2921 }
2922 case 4: {
2923 int expectedInt = getInt(expectedArray, base);
2924 int xInt = getInt(xArray, base);
2925 return compareAndSetInt(o, offset, expectedInt, xInt);
2926 }
2927 case 8: {
2928 long expectedLong = getLong(expectedArray, base);
2929 long xLong = getLong(xArray, base);
2930 return compareAndSetLong(o, offset, expectedLong, xLong);
2931 }
2932 default: {
2933 throw new UnsupportedOperationException();
2934 }
2935 }
2936 }
2937
2938 /**
2939 * Unblocks the given thread blocked on {@code park}, or, if it is
2940 * not blocked, causes the subsequent call to {@code park} not to
2941 * block. Note: this operation is "unsafe" solely because the
2942 * caller must somehow ensure that the thread has not been
2943 * destroyed. Nothing special is usually required to ensure this
2944 * when called from Java (in which there will ordinarily be a live
2945 * reference to the thread) but this is not nearly-automatically
2946 * so when calling from native code.
2947 *
2948 * @param thread the thread to unpark.
2949 */
2950 @IntrinsicCandidate
2951 public native void unpark(Object thread);
2952
2953 /**
2954 * Blocks current thread, returning when a balancing
2955 * {@code unpark} occurs, or a balancing {@code unpark} has
2956 * already occurred, or the thread is interrupted, or, if not
2957 * absolute and time is not zero, the given time nanoseconds have
2958 * elapsed, or if absolute, the given deadline in milliseconds
2959 * since Epoch has passed, or spuriously (i.e., returning for no
2960 * "reason"). Note: This operation is in the Unsafe class only
2961 * because {@code unpark} is, so it would be strange to place it
2962 * elsewhere.
2963 */
2964 @IntrinsicCandidate
2965 public native void park(boolean isAbsolute, long time);
2966
2967 /**
2968 * Gets the load average in the system run queue assigned
2969 * to the available processors averaged over various periods of time.
2970 * This method retrieves the given {@code nelem} samples and
2971 * assigns to the elements of the given {@code loadavg} array.
2972 * The system imposes a maximum of 3 samples, representing
2973 * averages over the last 1, 5, and 15 minutes, respectively.
2974 *
2975 * @param loadavg an array of double of size nelems
2976 * @param nelems the number of samples to be retrieved and
2977 * must be 1 to 3.
2978 *
2979 * @return the number of samples actually retrieved; or -1
2980 * if the load average is unobtainable.
2981 */
2982 public int getLoadAverage(double[] loadavg, int nelems) {
2983 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
2984 throw new ArrayIndexOutOfBoundsException();
2985 }
2986
2987 return getLoadAverage0(loadavg, nelems);
2988 }
2989
2990 // The following contain CAS-based Java implementations used on
2991 // platforms not supporting native instructions
2992
2993 /**
2994 * Atomically adds the given value to the current value of a field
2995 * or array element within the given object {@code o}
2996 * at the given {@code offset}.
2997 *
2998 * @param o object/array to update the field/element in
2999 * @param offset field/element offset
3000 * @param delta the value to add
3001 * @return the previous value
3002 * @since 1.8
3003 */
3004 @IntrinsicCandidate
3005 public final int getAndAddInt(Object o, long offset, int delta) {
3006 int v;
3007 do {
3008 v = getIntVolatile(o, offset);
3009 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
3010 return v;
3011 }
3012
3013 @ForceInline
3014 public final int getAndAddIntRelease(Object o, long offset, int delta) {
3015 int v;
3016 do {
3017 v = getInt(o, offset);
3018 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
3019 return v;
3020 }
3021
3022 @ForceInline
3023 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
3024 int v;
3025 do {
3026 v = getIntAcquire(o, offset);
3027 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
3028 return v;
3029 }
3030
3031 /**
3032 * Atomically adds the given value to the current value of a field
3033 * or array element within the given object {@code o}
3034 * at the given {@code offset}.
3035 *
3036 * @param o object/array to update the field/element in
3037 * @param offset field/element offset
3038 * @param delta the value to add
3039 * @return the previous value
3040 * @since 1.8
3041 */
3042 @IntrinsicCandidate
3043 public final long getAndAddLong(Object o, long offset, long delta) {
3044 long v;
3045 do {
3046 v = getLongVolatile(o, offset);
3047 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
3048 return v;
3049 }
3050
3051 @ForceInline
3052 public final long getAndAddLongRelease(Object o, long offset, long delta) {
3053 long v;
3054 do {
3055 v = getLong(o, offset);
3056 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
3057 return v;
3058 }
3059
3060 @ForceInline
3061 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
3062 long v;
3063 do {
3064 v = getLongAcquire(o, offset);
3065 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
3066 return v;
3067 }
3068
3069 @IntrinsicCandidate
3070 public final byte getAndAddByte(Object o, long offset, byte delta) {
3071 byte v;
3072 do {
3073 v = getByteVolatile(o, offset);
3074 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
3075 return v;
3076 }
3077
3078 @ForceInline
3079 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
3080 byte v;
3081 do {
3082 v = getByte(o, offset);
3083 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
3084 return v;
3085 }
3086
3087 @ForceInline
3088 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
3089 byte v;
3090 do {
3091 v = getByteAcquire(o, offset);
3092 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
3093 return v;
3094 }
3095
3096 @IntrinsicCandidate
3097 public final short getAndAddShort(Object o, long offset, short delta) {
3098 short v;
3099 do {
3100 v = getShortVolatile(o, offset);
3101 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
3102 return v;
3103 }
3104
3105 @ForceInline
3106 public final short getAndAddShortRelease(Object o, long offset, short delta) {
3107 short v;
3108 do {
3109 v = getShort(o, offset);
3110 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
3111 return v;
3112 }
3113
3114 @ForceInline
3115 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
3116 short v;
3117 do {
3118 v = getShortAcquire(o, offset);
3119 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
3120 return v;
3121 }
3122
3123 @ForceInline
3124 public final char getAndAddChar(Object o, long offset, char delta) {
3125 return (char) getAndAddShort(o, offset, (short) delta);
3126 }
3127
3128 @ForceInline
3129 public final char getAndAddCharRelease(Object o, long offset, char delta) {
3130 return (char) getAndAddShortRelease(o, offset, (short) delta);
3131 }
3132
3133 @ForceInline
3134 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
3135 return (char) getAndAddShortAcquire(o, offset, (short) delta);
3136 }
3137
3138 @ForceInline
3139 public final float getAndAddFloat(Object o, long offset, float delta) {
3140 int expectedBits;
3141 float v;
3142 do {
3143 // Load and CAS with the raw bits to avoid issues with NaNs and
3144 // possible bit conversion from signaling NaNs to quiet NaNs that
3145 // may result in the loop not terminating.
3146 expectedBits = getIntVolatile(o, offset);
3147 v = Float.intBitsToFloat(expectedBits);
3148 } while (!weakCompareAndSetInt(o, offset,
3149 expectedBits, Float.floatToRawIntBits(v + delta)));
3150 return v;
3151 }
3152
3153 @ForceInline
3154 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
3155 int expectedBits;
3156 float v;
3157 do {
3158 // Load and CAS with the raw bits to avoid issues with NaNs and
3159 // possible bit conversion from signaling NaNs to quiet NaNs that
3160 // may result in the loop not terminating.
3161 expectedBits = getInt(o, offset);
3162 v = Float.intBitsToFloat(expectedBits);
3163 } while (!weakCompareAndSetIntRelease(o, offset,
3164 expectedBits, Float.floatToRawIntBits(v + delta)));
3165 return v;
3166 }
3167
3168 @ForceInline
3169 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
3170 int expectedBits;
3171 float v;
3172 do {
3173 // Load and CAS with the raw bits to avoid issues with NaNs and
3174 // possible bit conversion from signaling NaNs to quiet NaNs that
3175 // may result in the loop not terminating.
3176 expectedBits = getIntAcquire(o, offset);
3177 v = Float.intBitsToFloat(expectedBits);
3178 } while (!weakCompareAndSetIntAcquire(o, offset,
3179 expectedBits, Float.floatToRawIntBits(v + delta)));
3180 return v;
3181 }
3182
3183 @ForceInline
3184 public final double getAndAddDouble(Object o, long offset, double delta) {
3185 long expectedBits;
3186 double v;
3187 do {
3188 // Load and CAS with the raw bits to avoid issues with NaNs and
3189 // possible bit conversion from signaling NaNs to quiet NaNs that
3190 // may result in the loop not terminating.
3191 expectedBits = getLongVolatile(o, offset);
3192 v = Double.longBitsToDouble(expectedBits);
3193 } while (!weakCompareAndSetLong(o, offset,
3194 expectedBits, Double.doubleToRawLongBits(v + delta)));
3195 return v;
3196 }
3197
3198 @ForceInline
3199 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
3200 long expectedBits;
3201 double v;
3202 do {
3203 // Load and CAS with the raw bits to avoid issues with NaNs and
3204 // possible bit conversion from signaling NaNs to quiet NaNs that
3205 // may result in the loop not terminating.
3206 expectedBits = getLong(o, offset);
3207 v = Double.longBitsToDouble(expectedBits);
3208 } while (!weakCompareAndSetLongRelease(o, offset,
3209 expectedBits, Double.doubleToRawLongBits(v + delta)));
3210 return v;
3211 }
3212
3213 @ForceInline
3214 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
3215 long expectedBits;
3216 double v;
3217 do {
3218 // Load and CAS with the raw bits to avoid issues with NaNs and
3219 // possible bit conversion from signaling NaNs to quiet NaNs that
3220 // may result in the loop not terminating.
3221 expectedBits = getLongAcquire(o, offset);
3222 v = Double.longBitsToDouble(expectedBits);
3223 } while (!weakCompareAndSetLongAcquire(o, offset,
3224 expectedBits, Double.doubleToRawLongBits(v + delta)));
3225 return v;
3226 }
3227
3228 /**
3229 * Atomically exchanges the given value with the current value of
3230 * a field or array element within the given object {@code o}
3231 * at the given {@code offset}.
3232 *
3233 * @param o object/array to update the field/element in
3234 * @param offset field/element offset
3235 * @param newValue new value
3236 * @return the previous value
3237 * @since 1.8
3238 */
3239 @IntrinsicCandidate
3240 public final int getAndSetInt(Object o, long offset, int newValue) {
3241 int v;
3242 do {
3243 v = getIntVolatile(o, offset);
3244 } while (!weakCompareAndSetInt(o, offset, v, newValue));
3245 return v;
3246 }
3247
3248 @ForceInline
3249 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
3250 int v;
3251 do {
3252 v = getInt(o, offset);
3253 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
3254 return v;
3255 }
3256
3257 @ForceInline
3258 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
3259 int v;
3260 do {
3261 v = getIntAcquire(o, offset);
3262 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
3263 return v;
3264 }
3265
3266 /**
3267 * Atomically exchanges the given value with the current value of
3268 * a field or array element within the given object {@code o}
3269 * at the given {@code offset}.
3270 *
3271 * @param o object/array to update the field/element in
3272 * @param offset field/element offset
3273 * @param newValue new value
3274 * @return the previous value
3275 * @since 1.8
3276 */
3277 @IntrinsicCandidate
3278 public final long getAndSetLong(Object o, long offset, long newValue) {
3279 long v;
3280 do {
3281 v = getLongVolatile(o, offset);
3282 } while (!weakCompareAndSetLong(o, offset, v, newValue));
3283 return v;
3284 }
3285
3286 @ForceInline
3287 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
3288 long v;
3289 do {
3290 v = getLong(o, offset);
3291 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
3292 return v;
3293 }
3294
3295 @ForceInline
3296 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
3297 long v;
3298 do {
3299 v = getLongAcquire(o, offset);
3300 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
3301 return v;
3302 }
3303
3304 /**
3305 * Atomically exchanges the given reference value with the current
3306 * reference value of a field or array element within the given
3307 * object {@code o} at the given {@code offset}.
3308 *
3309 * @param o object/array to update the field/element in
3310 * @param offset field/element offset
3311 * @param newValue new value
3312 * @return the previous value
3313 * @since 1.8
3314 */
3315 @IntrinsicCandidate
3316 public final Object getAndSetReference(Object o, long offset, Object newValue) {
3317 Object v;
3318 do {
3319 v = getReferenceVolatile(o, offset);
3320 } while (!weakCompareAndSetReference(o, offset, v, newValue));
3321 return v;
3322 }
3323
3324 @ForceInline
3325 public final Object getAndSetReference(Object o, long offset, Class<?> valueType, Object newValue) {
3326 Object v;
3327 do {
3328 v = getReferenceVolatile(o, offset);
3329 } while (!compareAndSetReference(o, offset, valueType, v, newValue));
3330 return v;
3331 }
3332
3333 @ForceInline
3334 public Object getAndSetFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, Object newValue) {
3335 Object v;
3336 do {
3337 v = getFlatValueVolatile(o, offset, layoutKind, valueType);
3338 } while (!compareAndSetFlatValue(o, offset, layoutKind, valueType, v, newValue));
3339 return v;
3340 }
3341
3342 @ForceInline
3343 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
3344 Object v;
3345 do {
3346 v = getReference(o, offset);
3347 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
3348 return v;
3349 }
3350
3351 @ForceInline
3352 public final Object getAndSetReferenceRelease(Object o, long offset, Class<?> valueType, Object newValue) {
3353 return getAndSetReference(o, offset, valueType, newValue);
3354 }
3355
3356 @ForceInline
3357 public Object getAndSetFlatValueRelease(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3358 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3359 }
3360
3361 @ForceInline
3362 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
3363 Object v;
3364 do {
3365 v = getReferenceAcquire(o, offset);
3366 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
3367 return v;
3368 }
3369
3370 @ForceInline
3371 public final Object getAndSetReferenceAcquire(Object o, long offset, Class<?> valueType, Object newValue) {
3372 return getAndSetReference(o, offset, valueType, newValue);
3373 }
3374
3375 @ForceInline
3376 public Object getAndSetFlatValueAcquire(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3377 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3378 }
3379
3380 @IntrinsicCandidate
3381 public final byte getAndSetByte(Object o, long offset, byte newValue) {
3382 byte v;
3383 do {
3384 v = getByteVolatile(o, offset);
3385 } while (!weakCompareAndSetByte(o, offset, v, newValue));
3386 return v;
3387 }
3388
3389 @ForceInline
3390 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
3391 byte v;
3392 do {
3393 v = getByte(o, offset);
3394 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
3395 return v;
3396 }
3397
3398 @ForceInline
3399 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
3400 byte v;
3401 do {
3402 v = getByteAcquire(o, offset);
3403 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
3404 return v;
3405 }
3406
3407 @ForceInline
3408 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
3409 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
3410 }
3411
3412 @ForceInline
3413 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
3414 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
3415 }
3416
3417 @ForceInline
3418 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
3419 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
3420 }
3421
3422 @IntrinsicCandidate
3423 public final short getAndSetShort(Object o, long offset, short newValue) {
3424 short v;
3425 do {
3426 v = getShortVolatile(o, offset);
3427 } while (!weakCompareAndSetShort(o, offset, v, newValue));
3428 return v;
3429 }
3430
3431 @ForceInline
3432 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
3433 short v;
3434 do {
3435 v = getShort(o, offset);
3436 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
3437 return v;
3438 }
3439
3440 @ForceInline
3441 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
3442 short v;
3443 do {
3444 v = getShortAcquire(o, offset);
3445 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
3446 return v;
3447 }
3448
3449 @ForceInline
3450 public final char getAndSetChar(Object o, long offset, char newValue) {
3451 return s2c(getAndSetShort(o, offset, c2s(newValue)));
3452 }
3453
3454 @ForceInline
3455 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
3456 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
3457 }
3458
3459 @ForceInline
3460 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
3461 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
3462 }
3463
3464 @ForceInline
3465 public final float getAndSetFloat(Object o, long offset, float newValue) {
3466 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
3467 return Float.intBitsToFloat(v);
3468 }
3469
3470 @ForceInline
3471 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
3472 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
3473 return Float.intBitsToFloat(v);
3474 }
3475
3476 @ForceInline
3477 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
3478 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
3479 return Float.intBitsToFloat(v);
3480 }
3481
3482 @ForceInline
3483 public final double getAndSetDouble(Object o, long offset, double newValue) {
3484 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
3485 return Double.longBitsToDouble(v);
3486 }
3487
3488 @ForceInline
3489 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
3490 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
3491 return Double.longBitsToDouble(v);
3492 }
3493
3494 @ForceInline
3495 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
3496 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
3497 return Double.longBitsToDouble(v);
3498 }
3499
3500
3501 // The following contain CAS-based Java implementations used on
3502 // platforms not supporting native instructions
3503
3504 @ForceInline
3505 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
3506 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
3507 }
3508
3509 @ForceInline
3510 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
3511 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
3512 }
3513
3514 @ForceInline
3515 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
3516 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
3517 }
3518
3519 @ForceInline
3520 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
3521 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
3522 }
3523
3524 @ForceInline
3525 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
3526 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
3527 }
3528
3529 @ForceInline
3530 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
3531 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
3532 }
3533
3534 @ForceInline
3535 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
3536 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
3537 }
3538
3539 @ForceInline
3540 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
3541 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
3542 }
3543
3544 @ForceInline
3545 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
3546 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
3547 }
3548
3549
3550 @ForceInline
3551 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
3552 byte current;
3553 do {
3554 current = getByteVolatile(o, offset);
3555 } while (!weakCompareAndSetByte(o, offset,
3556 current, (byte) (current | mask)));
3557 return current;
3558 }
3559
3560 @ForceInline
3561 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
3562 byte current;
3563 do {
3564 current = getByte(o, offset);
3565 } while (!weakCompareAndSetByteRelease(o, offset,
3566 current, (byte) (current | mask)));
3567 return current;
3568 }
3569
3570 @ForceInline
3571 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
3572 byte current;
3573 do {
3574 // Plain read, the value is a hint, the acquire CAS does the work
3575 current = getByte(o, offset);
3576 } while (!weakCompareAndSetByteAcquire(o, offset,
3577 current, (byte) (current | mask)));
3578 return current;
3579 }
3580
3581 @ForceInline
3582 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3583 byte current;
3584 do {
3585 current = getByteVolatile(o, offset);
3586 } while (!weakCompareAndSetByte(o, offset,
3587 current, (byte) (current & mask)));
3588 return current;
3589 }
3590
3591 @ForceInline
3592 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3593 byte current;
3594 do {
3595 current = getByte(o, offset);
3596 } while (!weakCompareAndSetByteRelease(o, offset,
3597 current, (byte) (current & mask)));
3598 return current;
3599 }
3600
3601 @ForceInline
3602 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3603 byte current;
3604 do {
3605 // Plain read, the value is a hint, the acquire CAS does the work
3606 current = getByte(o, offset);
3607 } while (!weakCompareAndSetByteAcquire(o, offset,
3608 current, (byte) (current & mask)));
3609 return current;
3610 }
3611
3612 @ForceInline
3613 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3614 byte current;
3615 do {
3616 current = getByteVolatile(o, offset);
3617 } while (!weakCompareAndSetByte(o, offset,
3618 current, (byte) (current ^ mask)));
3619 return current;
3620 }
3621
3622 @ForceInline
3623 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3624 byte current;
3625 do {
3626 current = getByte(o, offset);
3627 } while (!weakCompareAndSetByteRelease(o, offset,
3628 current, (byte) (current ^ mask)));
3629 return current;
3630 }
3631
3632 @ForceInline
3633 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3634 byte current;
3635 do {
3636 // Plain read, the value is a hint, the acquire CAS does the work
3637 current = getByte(o, offset);
3638 } while (!weakCompareAndSetByteAcquire(o, offset,
3639 current, (byte) (current ^ mask)));
3640 return current;
3641 }
3642
3643
3644 @ForceInline
3645 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3646 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3647 }
3648
3649 @ForceInline
3650 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3651 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3652 }
3653
3654 @ForceInline
3655 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3656 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3657 }
3658
3659 @ForceInline
3660 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3661 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3662 }
3663
3664 @ForceInline
3665 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3666 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3667 }
3668
3669 @ForceInline
3670 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3671 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3672 }
3673
3674 @ForceInline
3675 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3676 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3677 }
3678
3679 @ForceInline
3680 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3681 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3682 }
3683
3684 @ForceInline
3685 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3686 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3687 }
3688
3689
3690 @ForceInline
3691 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3692 short current;
3693 do {
3694 current = getShortVolatile(o, offset);
3695 } while (!weakCompareAndSetShort(o, offset,
3696 current, (short) (current | mask)));
3697 return current;
3698 }
3699
3700 @ForceInline
3701 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3702 short current;
3703 do {
3704 current = getShort(o, offset);
3705 } while (!weakCompareAndSetShortRelease(o, offset,
3706 current, (short) (current | mask)));
3707 return current;
3708 }
3709
3710 @ForceInline
3711 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3712 short current;
3713 do {
3714 // Plain read, the value is a hint, the acquire CAS does the work
3715 current = getShort(o, offset);
3716 } while (!weakCompareAndSetShortAcquire(o, offset,
3717 current, (short) (current | mask)));
3718 return current;
3719 }
3720
3721 @ForceInline
3722 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3723 short current;
3724 do {
3725 current = getShortVolatile(o, offset);
3726 } while (!weakCompareAndSetShort(o, offset,
3727 current, (short) (current & mask)));
3728 return current;
3729 }
3730
3731 @ForceInline
3732 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3733 short current;
3734 do {
3735 current = getShort(o, offset);
3736 } while (!weakCompareAndSetShortRelease(o, offset,
3737 current, (short) (current & mask)));
3738 return current;
3739 }
3740
3741 @ForceInline
3742 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3743 short current;
3744 do {
3745 // Plain read, the value is a hint, the acquire CAS does the work
3746 current = getShort(o, offset);
3747 } while (!weakCompareAndSetShortAcquire(o, offset,
3748 current, (short) (current & mask)));
3749 return current;
3750 }
3751
3752 @ForceInline
3753 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3754 short current;
3755 do {
3756 current = getShortVolatile(o, offset);
3757 } while (!weakCompareAndSetShort(o, offset,
3758 current, (short) (current ^ mask)));
3759 return current;
3760 }
3761
3762 @ForceInline
3763 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3764 short current;
3765 do {
3766 current = getShort(o, offset);
3767 } while (!weakCompareAndSetShortRelease(o, offset,
3768 current, (short) (current ^ mask)));
3769 return current;
3770 }
3771
3772 @ForceInline
3773 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3774 short current;
3775 do {
3776 // Plain read, the value is a hint, the acquire CAS does the work
3777 current = getShort(o, offset);
3778 } while (!weakCompareAndSetShortAcquire(o, offset,
3779 current, (short) (current ^ mask)));
3780 return current;
3781 }
3782
3783
3784 @ForceInline
3785 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3786 int current;
3787 do {
3788 current = getIntVolatile(o, offset);
3789 } while (!weakCompareAndSetInt(o, offset,
3790 current, current | mask));
3791 return current;
3792 }
3793
3794 @ForceInline
3795 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3796 int current;
3797 do {
3798 current = getInt(o, offset);
3799 } while (!weakCompareAndSetIntRelease(o, offset,
3800 current, current | mask));
3801 return current;
3802 }
3803
3804 @ForceInline
3805 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3806 int current;
3807 do {
3808 // Plain read, the value is a hint, the acquire CAS does the work
3809 current = getInt(o, offset);
3810 } while (!weakCompareAndSetIntAcquire(o, offset,
3811 current, current | mask));
3812 return current;
3813 }
3814
3815 /**
3816 * Atomically replaces the current value of a field or array element within
3817 * the given object with the result of bitwise AND between the current value
3818 * and mask.
3819 *
3820 * @param o object/array to update the field/element in
3821 * @param offset field/element offset
3822 * @param mask the mask value
3823 * @return the previous value
3824 * @since 9
3825 */
3826 @ForceInline
3827 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3828 int current;
3829 do {
3830 current = getIntVolatile(o, offset);
3831 } while (!weakCompareAndSetInt(o, offset,
3832 current, current & mask));
3833 return current;
3834 }
3835
3836 @ForceInline
3837 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3838 int current;
3839 do {
3840 current = getInt(o, offset);
3841 } while (!weakCompareAndSetIntRelease(o, offset,
3842 current, current & mask));
3843 return current;
3844 }
3845
3846 @ForceInline
3847 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3848 int current;
3849 do {
3850 // Plain read, the value is a hint, the acquire CAS does the work
3851 current = getInt(o, offset);
3852 } while (!weakCompareAndSetIntAcquire(o, offset,
3853 current, current & mask));
3854 return current;
3855 }
3856
3857 @ForceInline
3858 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3859 int current;
3860 do {
3861 current = getIntVolatile(o, offset);
3862 } while (!weakCompareAndSetInt(o, offset,
3863 current, current ^ mask));
3864 return current;
3865 }
3866
3867 @ForceInline
3868 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3869 int current;
3870 do {
3871 current = getInt(o, offset);
3872 } while (!weakCompareAndSetIntRelease(o, offset,
3873 current, current ^ mask));
3874 return current;
3875 }
3876
3877 @ForceInline
3878 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3879 int current;
3880 do {
3881 // Plain read, the value is a hint, the acquire CAS does the work
3882 current = getInt(o, offset);
3883 } while (!weakCompareAndSetIntAcquire(o, offset,
3884 current, current ^ mask));
3885 return current;
3886 }
3887
3888
3889 @ForceInline
3890 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3891 long current;
3892 do {
3893 current = getLongVolatile(o, offset);
3894 } while (!weakCompareAndSetLong(o, offset,
3895 current, current | mask));
3896 return current;
3897 }
3898
3899 @ForceInline
3900 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3901 long current;
3902 do {
3903 current = getLong(o, offset);
3904 } while (!weakCompareAndSetLongRelease(o, offset,
3905 current, current | mask));
3906 return current;
3907 }
3908
3909 @ForceInline
3910 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3911 long current;
3912 do {
3913 // Plain read, the value is a hint, the acquire CAS does the work
3914 current = getLong(o, offset);
3915 } while (!weakCompareAndSetLongAcquire(o, offset,
3916 current, current | mask));
3917 return current;
3918 }
3919
3920 @ForceInline
3921 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3922 long current;
3923 do {
3924 current = getLongVolatile(o, offset);
3925 } while (!weakCompareAndSetLong(o, offset,
3926 current, current & mask));
3927 return current;
3928 }
3929
3930 @ForceInline
3931 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3932 long current;
3933 do {
3934 current = getLong(o, offset);
3935 } while (!weakCompareAndSetLongRelease(o, offset,
3936 current, current & mask));
3937 return current;
3938 }
3939
3940 @ForceInline
3941 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3942 long current;
3943 do {
3944 // Plain read, the value is a hint, the acquire CAS does the work
3945 current = getLong(o, offset);
3946 } while (!weakCompareAndSetLongAcquire(o, offset,
3947 current, current & mask));
3948 return current;
3949 }
3950
3951 @ForceInline
3952 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3953 long current;
3954 do {
3955 current = getLongVolatile(o, offset);
3956 } while (!weakCompareAndSetLong(o, offset,
3957 current, current ^ mask));
3958 return current;
3959 }
3960
3961 @ForceInline
3962 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
3963 long current;
3964 do {
3965 current = getLong(o, offset);
3966 } while (!weakCompareAndSetLongRelease(o, offset,
3967 current, current ^ mask));
3968 return current;
3969 }
3970
3971 @ForceInline
3972 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
3973 long current;
3974 do {
3975 // Plain read, the value is a hint, the acquire CAS does the work
3976 current = getLong(o, offset);
3977 } while (!weakCompareAndSetLongAcquire(o, offset,
3978 current, current ^ mask));
3979 return current;
3980 }
3981
3982
3983
3984 /**
3985 * Ensures that loads before the fence will not be reordered with loads and
3986 * stores after the fence; a "LoadLoad plus LoadStore barrier".
3987 *
3988 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
3989 * (an "acquire fence").
3990 *
3991 * Provides a LoadLoad barrier followed by a LoadStore barrier.
3992 *
3993 * @since 1.8
3994 */
3995 @IntrinsicCandidate
3996 public final void loadFence() {
3997 // If loadFence intrinsic is not available, fall back to full fence.
3998 fullFence();
3999 }
4000
4001 /**
4002 * Ensures that loads and stores before the fence will not be reordered with
4003 * stores after the fence; a "StoreStore plus LoadStore barrier".
4004 *
4005 * Corresponds to C11 atomic_thread_fence(memory_order_release)
4006 * (a "release fence").
4007 *
4008 * Provides a StoreStore barrier followed by a LoadStore barrier.
4009 *
4010 * @since 1.8
4011 */
4012 @IntrinsicCandidate
4013 public final void storeFence() {
4014 // If storeFence intrinsic is not available, fall back to full fence.
4015 fullFence();
4016 }
4017
4018 /**
4019 * Ensures that loads and stores before the fence will not be reordered
4020 * with loads and stores after the fence. Implies the effects of both
4021 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
4022 * barrier.
4023 *
4024 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
4025 * @since 1.8
4026 */
4027 @IntrinsicCandidate
4028 public native void fullFence();
4029
4030 /**
4031 * Ensures that loads before the fence will not be reordered with
4032 * loads after the fence.
4033 *
4034 * @implNote
4035 * This method is operationally equivalent to {@link #loadFence()}.
4036 *
4037 * @since 9
4038 */
4039 public final void loadLoadFence() {
4040 loadFence();
4041 }
4042
4043 /**
4044 * Ensures that stores before the fence will not be reordered with
4045 * stores after the fence.
4046 *
4047 * @since 9
4048 */
4049 @IntrinsicCandidate
4050 public final void storeStoreFence() {
4051 // If storeStoreFence intrinsic is not available, fall back to storeFence.
4052 storeFence();
4053 }
4054
4055 /**
4056 * Throws IllegalAccessError; for use by the VM for access control
4057 * error support.
4058 * @since 1.8
4059 */
4060 private static void throwIllegalAccessError() {
4061 throw new IllegalAccessError();
4062 }
4063
4064 /**
4065 * Throws NoSuchMethodError; for use by the VM for redefinition support.
4066 * @since 13
4067 */
4068 private static void throwNoSuchMethodError() {
4069 throw new NoSuchMethodError();
4070 }
4071
4072 /**
4073 * @return Returns true if the native byte ordering of this
4074 * platform is big-endian, false if it is little-endian.
4075 */
4076 public final boolean isBigEndian() { return BIG_ENDIAN; }
4077
4078 /**
4079 * @return Returns true if this platform is capable of performing
4080 * accesses at addresses which are not aligned for the type of the
4081 * primitive type being accessed, false otherwise.
4082 */
4083 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
4084
4085 /**
4086 * Fetches a value at some byte offset into a given Java object.
4087 * More specifically, fetches a value within the given object
4088 * <code>o</code> at the given offset, or (if <code>o</code> is
4089 * null) from the memory address whose numerical value is the
4090 * given offset. <p>
4091 *
4092 * The specification of this method is the same as {@link
4093 * #getLong(Object, long)} except that the offset does not need to
4094 * have been obtained from {@link #objectFieldOffset} on the
4095 * {@link java.lang.reflect.Field} of some Java field. The value
4096 * in memory is raw data, and need not correspond to any Java
4097 * variable. Unless <code>o</code> is null, the value accessed
4098 * must be entirely within the allocated object. The endianness
4099 * of the value in memory is the endianness of the native platform.
4100 *
4101 * <p> The read will be atomic with respect to the largest power
4102 * of two that divides the GCD of the offset and the storage size.
4103 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
4104 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4105 * respectively. There are no other guarantees of atomicity.
4106 * <p>
4107 * 8-byte atomicity is only guaranteed on platforms on which
4108 * support atomic accesses to longs.
4109 *
4110 * @param o Java heap object in which the value resides, if any, else
4111 * null
4112 * @param offset The offset in bytes from the start of the object
4113 * @return the value fetched from the indicated object
4114 * @throws RuntimeException No defined exceptions are thrown, not even
4115 * {@link NullPointerException}
4116 * @since 9
4117 */
4118 @IntrinsicCandidate
4119 public final long getLongUnaligned(Object o, long offset) {
4120 if ((offset & 7) == 0) {
4121 return getLong(o, offset);
4122 } else if ((offset & 3) == 0) {
4123 return makeLong(getInt(o, offset),
4124 getInt(o, offset + 4));
4125 } else if ((offset & 1) == 0) {
4126 return makeLong(getShort(o, offset),
4127 getShort(o, offset + 2),
4128 getShort(o, offset + 4),
4129 getShort(o, offset + 6));
4130 } else {
4131 return makeLong(getByte(o, offset),
4132 getByte(o, offset + 1),
4133 getByte(o, offset + 2),
4134 getByte(o, offset + 3),
4135 getByte(o, offset + 4),
4136 getByte(o, offset + 5),
4137 getByte(o, offset + 6),
4138 getByte(o, offset + 7));
4139 }
4140 }
4141 /**
4142 * As {@link #getLongUnaligned(Object, long)} but with an
4143 * additional argument which specifies the endianness of the value
4144 * as stored in memory.
4145 *
4146 * @param o Java heap object in which the variable resides
4147 * @param offset The offset in bytes from the start of the object
4148 * @param bigEndian The endianness of the value
4149 * @return the value fetched from the indicated object
4150 * @since 9
4151 */
4152 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
4153 return convEndian(bigEndian, getLongUnaligned(o, offset));
4154 }
4155
4156 /** @see #getLongUnaligned(Object, long) */
4157 @IntrinsicCandidate
4158 public final int getIntUnaligned(Object o, long offset) {
4159 if ((offset & 3) == 0) {
4160 return getInt(o, offset);
4161 } else if ((offset & 1) == 0) {
4162 return makeInt(getShort(o, offset),
4163 getShort(o, offset + 2));
4164 } else {
4165 return makeInt(getByte(o, offset),
4166 getByte(o, offset + 1),
4167 getByte(o, offset + 2),
4168 getByte(o, offset + 3));
4169 }
4170 }
4171 /** @see #getLongUnaligned(Object, long, boolean) */
4172 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
4173 return convEndian(bigEndian, getIntUnaligned(o, offset));
4174 }
4175
4176 /** @see #getLongUnaligned(Object, long) */
4177 @IntrinsicCandidate
4178 public final short getShortUnaligned(Object o, long offset) {
4179 if ((offset & 1) == 0) {
4180 return getShort(o, offset);
4181 } else {
4182 return makeShort(getByte(o, offset),
4183 getByte(o, offset + 1));
4184 }
4185 }
4186 /** @see #getLongUnaligned(Object, long, boolean) */
4187 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
4188 return convEndian(bigEndian, getShortUnaligned(o, offset));
4189 }
4190
4191 /** @see #getLongUnaligned(Object, long) */
4192 @IntrinsicCandidate
4193 public final char getCharUnaligned(Object o, long offset) {
4194 if ((offset & 1) == 0) {
4195 return getChar(o, offset);
4196 } else {
4197 return (char)makeShort(getByte(o, offset),
4198 getByte(o, offset + 1));
4199 }
4200 }
4201
4202 /** @see #getLongUnaligned(Object, long, boolean) */
4203 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
4204 return convEndian(bigEndian, getCharUnaligned(o, offset));
4205 }
4206
4207 /**
4208 * Stores a value at some byte offset into a given Java object.
4209 * <p>
4210 * The specification of this method is the same as {@link
4211 * #getLong(Object, long)} except that the offset does not need to
4212 * have been obtained from {@link #objectFieldOffset} on the
4213 * {@link java.lang.reflect.Field} of some Java field. The value
4214 * in memory is raw data, and need not correspond to any Java
4215 * variable. The endianness of the value in memory is the
4216 * endianness of the native platform.
4217 * <p>
4218 * The write will be atomic with respect to the largest power of
4219 * two that divides the GCD of the offset and the storage size.
4220 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
4221 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4222 * respectively. There are no other guarantees of atomicity.
4223 * <p>
4224 * 8-byte atomicity is only guaranteed on platforms on which
4225 * support atomic accesses to longs.
4226 *
4227 * @param o Java heap object in which the value resides, if any, else
4228 * null
4229 * @param offset The offset in bytes from the start of the object
4230 * @param x the value to store
4231 * @throws RuntimeException No defined exceptions are thrown, not even
4232 * {@link NullPointerException}
4233 * @since 9
4234 */
4235 @IntrinsicCandidate
4236 public final void putLongUnaligned(Object o, long offset, long x) {
4237 if ((offset & 7) == 0) {
4238 putLong(o, offset, x);
4239 } else if ((offset & 3) == 0) {
4240 putLongParts(o, offset,
4241 (int)(x >> 0),
4242 (int)(x >>> 32));
4243 } else if ((offset & 1) == 0) {
4244 putLongParts(o, offset,
4245 (short)(x >>> 0),
4246 (short)(x >>> 16),
4247 (short)(x >>> 32),
4248 (short)(x >>> 48));
4249 } else {
4250 putLongParts(o, offset,
4251 (byte)(x >>> 0),
4252 (byte)(x >>> 8),
4253 (byte)(x >>> 16),
4254 (byte)(x >>> 24),
4255 (byte)(x >>> 32),
4256 (byte)(x >>> 40),
4257 (byte)(x >>> 48),
4258 (byte)(x >>> 56));
4259 }
4260 }
4261
4262 /**
4263 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
4264 * argument which specifies the endianness of the value as stored in memory.
4265 * @param o Java heap object in which the value resides
4266 * @param offset The offset in bytes from the start of the object
4267 * @param x the value to store
4268 * @param bigEndian The endianness of the value
4269 * @throws RuntimeException No defined exceptions are thrown, not even
4270 * {@link NullPointerException}
4271 * @since 9
4272 */
4273 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
4274 putLongUnaligned(o, offset, convEndian(bigEndian, x));
4275 }
4276
4277 /** @see #putLongUnaligned(Object, long, long) */
4278 @IntrinsicCandidate
4279 public final void putIntUnaligned(Object o, long offset, int x) {
4280 if ((offset & 3) == 0) {
4281 putInt(o, offset, x);
4282 } else if ((offset & 1) == 0) {
4283 putIntParts(o, offset,
4284 (short)(x >> 0),
4285 (short)(x >>> 16));
4286 } else {
4287 putIntParts(o, offset,
4288 (byte)(x >>> 0),
4289 (byte)(x >>> 8),
4290 (byte)(x >>> 16),
4291 (byte)(x >>> 24));
4292 }
4293 }
4294 /** @see #putLongUnaligned(Object, long, long, boolean) */
4295 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
4296 putIntUnaligned(o, offset, convEndian(bigEndian, x));
4297 }
4298
4299 /** @see #putLongUnaligned(Object, long, long) */
4300 @IntrinsicCandidate
4301 public final void putShortUnaligned(Object o, long offset, short x) {
4302 if ((offset & 1) == 0) {
4303 putShort(o, offset, x);
4304 } else {
4305 putShortParts(o, offset,
4306 (byte)(x >>> 0),
4307 (byte)(x >>> 8));
4308 }
4309 }
4310 /** @see #putLongUnaligned(Object, long, long, boolean) */
4311 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
4312 putShortUnaligned(o, offset, convEndian(bigEndian, x));
4313 }
4314
4315 /** @see #putLongUnaligned(Object, long, long) */
4316 @IntrinsicCandidate
4317 public final void putCharUnaligned(Object o, long offset, char x) {
4318 putShortUnaligned(o, offset, (short)x);
4319 }
4320 /** @see #putLongUnaligned(Object, long, long, boolean) */
4321 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
4322 putCharUnaligned(o, offset, convEndian(bigEndian, x));
4323 }
4324
4325 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
4326
4327 // These methods construct integers from bytes. The byte ordering
4328 // is the native endianness of this platform.
4329 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4330 return ((toUnsignedLong(i0) << pickPos(56, 0))
4331 | (toUnsignedLong(i1) << pickPos(56, 8))
4332 | (toUnsignedLong(i2) << pickPos(56, 16))
4333 | (toUnsignedLong(i3) << pickPos(56, 24))
4334 | (toUnsignedLong(i4) << pickPos(56, 32))
4335 | (toUnsignedLong(i5) << pickPos(56, 40))
4336 | (toUnsignedLong(i6) << pickPos(56, 48))
4337 | (toUnsignedLong(i7) << pickPos(56, 56)));
4338 }
4339 private static long makeLong(short i0, short i1, short i2, short i3) {
4340 return ((toUnsignedLong(i0) << pickPos(48, 0))
4341 | (toUnsignedLong(i1) << pickPos(48, 16))
4342 | (toUnsignedLong(i2) << pickPos(48, 32))
4343 | (toUnsignedLong(i3) << pickPos(48, 48)));
4344 }
4345 private static long makeLong(int i0, int i1) {
4346 return (toUnsignedLong(i0) << pickPos(32, 0))
4347 | (toUnsignedLong(i1) << pickPos(32, 32));
4348 }
4349 private static int makeInt(short i0, short i1) {
4350 return (toUnsignedInt(i0) << pickPos(16, 0))
4351 | (toUnsignedInt(i1) << pickPos(16, 16));
4352 }
4353 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
4354 return ((toUnsignedInt(i0) << pickPos(24, 0))
4355 | (toUnsignedInt(i1) << pickPos(24, 8))
4356 | (toUnsignedInt(i2) << pickPos(24, 16))
4357 | (toUnsignedInt(i3) << pickPos(24, 24)));
4358 }
4359 private static short makeShort(byte i0, byte i1) {
4360 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
4361 | (toUnsignedInt(i1) << pickPos(8, 8)));
4362 }
4363
4364 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
4365 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
4366 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
4367
4368 // These methods write integers to memory from smaller parts
4369 // provided by their caller. The ordering in which these parts
4370 // are written is the native endianness of this platform.
4371 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4372 putByte(o, offset + 0, pick(i0, i7));
4373 putByte(o, offset + 1, pick(i1, i6));
4374 putByte(o, offset + 2, pick(i2, i5));
4375 putByte(o, offset + 3, pick(i3, i4));
4376 putByte(o, offset + 4, pick(i4, i3));
4377 putByte(o, offset + 5, pick(i5, i2));
4378 putByte(o, offset + 6, pick(i6, i1));
4379 putByte(o, offset + 7, pick(i7, i0));
4380 }
4381 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
4382 putShort(o, offset + 0, pick(i0, i3));
4383 putShort(o, offset + 2, pick(i1, i2));
4384 putShort(o, offset + 4, pick(i2, i1));
4385 putShort(o, offset + 6, pick(i3, i0));
4386 }
4387 private void putLongParts(Object o, long offset, int i0, int i1) {
4388 putInt(o, offset + 0, pick(i0, i1));
4389 putInt(o, offset + 4, pick(i1, i0));
4390 }
4391 private void putIntParts(Object o, long offset, short i0, short i1) {
4392 putShort(o, offset + 0, pick(i0, i1));
4393 putShort(o, offset + 2, pick(i1, i0));
4394 }
4395 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
4396 putByte(o, offset + 0, pick(i0, i3));
4397 putByte(o, offset + 1, pick(i1, i2));
4398 putByte(o, offset + 2, pick(i2, i1));
4399 putByte(o, offset + 3, pick(i3, i0));
4400 }
4401 private void putShortParts(Object o, long offset, byte i0, byte i1) {
4402 putByte(o, offset + 0, pick(i0, i1));
4403 putByte(o, offset + 1, pick(i1, i0));
4404 }
4405
4406 // Zero-extend an integer
4407 private static int toUnsignedInt(byte n) { return n & 0xff; }
4408 private static int toUnsignedInt(short n) { return n & 0xffff; }
4409 private static long toUnsignedLong(byte n) { return n & 0xffl; }
4410 private static long toUnsignedLong(short n) { return n & 0xffffl; }
4411 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
4412
4413 // Maybe byte-reverse an integer
4414 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
4415 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
4416 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
4417 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
4418
4419
4420
4421 private native long allocateMemory0(long bytes);
4422 private native long reallocateMemory0(long address, long bytes);
4423 private native void freeMemory0(long address);
4424 @IntrinsicCandidate
4425 private native void setMemory0(Object o, long offset, long bytes, byte value);
4426 @IntrinsicCandidate
4427 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
4428 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
4429 private native long objectFieldOffset0(Field f); // throws IAE
4430 private native long knownObjectFieldOffset0(Class<?> c, String name); // error code: -1 not found, -2 static
4431 private native long staticFieldOffset0(Field f); // throws IAE
4432 private native Object staticFieldBase0(Field f); // throws IAE
4433 private native boolean shouldBeInitialized0(Class<?> c);
4434 private native void ensureClassInitialized0(Class<?> c);
4435 private native void notifyStrictStaticAccess0(Class<?> c, long staticFieldOffset, boolean writing);
4436 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
4437 private native int arrayBaseOffset1(Object[] array);
4438 private native int arrayIndexScale0(Class<?> arrayClass);
4439 private native int arrayIndexScale1(Object[] array);
4440 private native long getObjectSize0(Object o);
4441 private native int getLoadAverage0(double[] loadavg, int nelems);
4442
4443
4444 /**
4445 * Invokes the given direct byte buffer's cleaner, if any.
4446 *
4447 * @param directBuffer a direct byte buffer
4448 * @throws NullPointerException if {@code directBuffer} is null
4449 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
4450 * or is a {@link java.nio.Buffer#slice slice}, or is a
4451 * {@link java.nio.Buffer#duplicate duplicate}
4452 */
4453 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
4454 if (!directBuffer.isDirect())
4455 throw new IllegalArgumentException("buffer is non-direct");
4456
4457 DirectBuffer db = (DirectBuffer) directBuffer;
4458 if (db.attachment() != null)
4459 throw new IllegalArgumentException("duplicate or slice");
4460
4461 Cleaner cleaner = db.cleaner();
4462 if (cleaner != null) {
4463 cleaner.clean();
4464 }
4465 }
4466 }