1 /*
2 * Copyright (c) 2000, 2026, 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.vm.annotation.AOTRuntimeSetup;
29 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
30 import jdk.internal.vm.annotation.ForceInline;
31 import jdk.internal.vm.annotation.IntrinsicCandidate;
32 import jdk.internal.value.ValueClass;
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 * <h2><a id="undefined-behavior">Undefined Behavior</a></h2>
47 * For performance reasons, {@code Unsafe} is allowed to work outside the
48 * restrictions enforced by the JVM. As a result, it is the responsibility of
49 * the caller to ensure that an invocation of an {@code Unsafe} method is
50 * conformant, and failure to do so will result in undefined behavior. The
51 * runtime and the JIT compiler may assume that undefined behavior never
52 * happens, and operate accordingly. For example, the runtime assumes that each
53 * object has a header with a particular layout, and if the users use
54 * {@code Unsafe} to overwrite this header with invalid data, the behavior of
55 * the runtime becomes unpredictable. Another example is that the JIT compiler
56 * may assume that accesses on separate objects are unrelated, and schedule
57 * each of them without taking into consideration the others. If there is an
58 * {@code Unsafe} access that is out of bounds and points to object different
59 * from the declared base, the program may execute in a way that a variable
60 * seems to have multiple values at the same time. As a result, when a program
61 * exhibits undefined behavior, there is no restrictions on its behaviors. Such
62 * behaviors may include but not be limited to:
63 *
64 * <ul>
65 * <li>Working as expected.
66 * <li>Crashing the VM.
67 * <li>Corruption of the heap or JVM memory.
68 * <li>Nonsensical variable value. E.g. an {@code int} may appear to be
69 * simultaneously 0 and 1.
70 * <li>Impossible code execution. E.g. the branches of an {@code if} are
71 * both executed or both not executed.
72 * <li>Wiping out the hard drive.
73 * </ul>
74 *
75 * Undefined behavior, as described in this class, is analogous to the
76 * terminology with the same name in the C++ language.
77 * <p>
78 * Some methods (e.g. {@link #getInt}) exhibit undefined behavior if they
79 * are invoked at runtime with illegal arguments. This means that they will
80 * never exhibit undefined behavior if they are not actually reachable at
81 * runtime. On the other hands, other methods (e.g.
82 * {@link #allocateInstance(Class)}) exhibit undefined behavior if they are
83 * used incorrectly, even if the invocation may not be reachable at runtime.
84 * The analogous terminology in C++ is that such programs are ill-formed.
85 * <p>
86 * For methods exhibiting undefined behavior if they are invoked at runtime
87 * with illegal arguments, undefined behavior may time travel. That is, if a
88 * control path may eventually reach an invocation of an {@code Unsafe} method
89 * with illegal arguments, the symptoms of undefined behavior may be present
90 * even before the invocation of the {@code Unsafe} method. This is because the
91 * JIT compiler may have certain assumptions about the inputs of an
92 * {@code Unsafe} invocation, these assumptions may propagate backward to
93 * previous statements, leading to wrong executions if the assumptions are
94 * invalid.
95 *
96 * @author John R. Rose
97 * @see #getUnsafe
98 */
99 @AOTSafeClassInitializer
100 public final class Unsafe {
101
102 private static native void registerNatives();
103 static {
104 runtimeSetup();
105 }
106
107 /// BASE_OFFSET, INDEX_SCALE, and ADDRESS_SIZE fields are equivalent if the
108 /// AOT initialized heap is reused, so just register natives
109 @AOTRuntimeSetup
110 private static void runtimeSetup() {
111 registerNatives();
112 }
113
114 private Unsafe() {}
115
116 private static final Unsafe theUnsafe = new Unsafe();
117
118 /**
119 * Provides the caller with the capability of performing unsafe
120 * operations.
121 *
122 * <p>The returned {@code Unsafe} object should be carefully guarded
123 * by the caller, since it can be used to read and write data at arbitrary
124 * memory addresses. It must never be passed to untrusted code.
125 *
126 * <p>Most methods in this class are very low-level, and correspond to a
127 * small number of hardware instructions (on typical machines). Compilers
128 * are encouraged to optimize these methods accordingly.
129 *
130 * <p>Here is a suggested idiom for using unsafe operations:
131 *
132 * <pre> {@code
133 * class MyTrustedClass {
134 * private static final Unsafe unsafe = Unsafe.getUnsafe();
135 * ...
136 * private long myCountAddress = ...;
137 * public int getCount() { return unsafe.getByte(myCountAddress); }
138 * }}</pre>
139 *
140 * (It may assist compilers to make the local variable {@code final}.)
141 */
142 public static Unsafe getUnsafe() {
143 return theUnsafe;
144 }
145
146 //--- peek and poke operations
147 // (compilers should optimize these to memory ops)
148
149 // These work on object fields in the Java heap.
150 // They will not work on elements of packed arrays.
151
152 /**
153 * Fetches a value from a given Java variable.
154 * More specifically, fetches a field or array element within the given
155 * object {@code o} at the given offset, or (if {@code o} is null)
156 * from the memory address whose numerical value is the given offset.
157 * <p>
158 * The results are undefined unless one of the following cases is true:
159 * <ul>
160 * <li>The offset was obtained from {@link #objectFieldOffset} on
161 * the {@link java.lang.reflect.Field} of some Java field and the object
162 * referred to by {@code o} is of a class compatible with that
163 * field's class.
164 *
165 * <li>The offset and object reference {@code o} (either null or
166 * non-null) were both obtained via {@link #staticFieldOffset}
167 * and {@link #staticFieldBase} (respectively) from the
168 * reflective {@link Field} representation of some Java field.
169 *
170 * <li>The object referred to by {@code o} is an array, and the offset
171 * is an integer of the form {@code B+N*S}, where {@code N} is
172 * a valid index into the array, and {@code B} and {@code S} are
173 * the values obtained by {@link #arrayBaseOffset} and {@link
174 * #arrayIndexScale} (respectively) from the array's class. The value
175 * referred to is the {@code N}<em>th</em> element of the array.
176 *
177 * </ul>
178 * <p>
179 * If one of the above cases is true, the call references a specific Java
180 * variable (field or array element). However, the results are undefined
181 * if that variable is not in fact of the type returned by this method.
182 * <p>
183 * This method refers to a variable by means of two parameters, and so
184 * it provides (in effect) a <em>double-register</em> addressing mode
185 * for Java variables. When the object reference is null, this method
186 * uses its offset as an absolute address. This is similar in operation
187 * to methods such as {@link #getInt(long)}, which provide (in effect) a
188 * <em>single-register</em> addressing mode for non-Java variables.
189 * However, because Java variables may have a different layout in memory
190 * from non-Java variables, programmers should not assume that these
191 * two addressing modes are ever equivalent. Also, programmers should
192 * remember that offsets from the double-register addressing mode cannot
193 * be portably confused with longs used in the single-register addressing
194 * mode.
195 *
196 * @param o Java heap object in which the variable resides, if any, else
197 * null
198 * @param offset indication of where the variable resides in a Java heap
199 * object, if any, else a memory address locating the variable
200 * statically
201 * @return the value fetched from the indicated Java variable
202 * @throws RuntimeException No defined exceptions are thrown, not even
203 * {@link NullPointerException}
204 */
205 @IntrinsicCandidate
206 public native int getInt(Object o, long offset);
207
208 /**
209 * Stores a value into a given Java variable.
210 * <p>
211 * The first two parameters are interpreted exactly as with
212 * {@link #getInt(Object, long)} to refer to a specific
213 * Java variable (field or array element). The given value
214 * is stored into that variable.
215 * <p>
216 * The variable must be of the same type as the method
217 * parameter {@code x}.
218 *
219 * @param o Java heap object in which the variable resides, if any, else
220 * null
221 * @param offset indication of where the variable resides in a Java heap
222 * object, if any, else a memory address locating the variable
223 * statically
224 * @param x the value to store into the indicated Java variable
225 * @throws RuntimeException No defined exceptions are thrown, not even
226 * {@link NullPointerException}
227 */
228 @IntrinsicCandidate
229 public native void putInt(Object o, long offset, int x);
230
231 /**
232 * Returns true if the given field is flattened.
233 */
234 public boolean isFlatField(Field f) {
235 if (f == null) {
236 throw new NullPointerException();
237 }
238 return isFlatField0(f);
239 }
240
241 private native boolean isFlatField0(Object o);
242
243 /* Returns true if the given field has a null marker
244 * <p>
245 * Nullable flat fields are stored in a flattened representation
246 * and have an associated null marker to indicate if the the field value is
247 * null or the one stored with the flat representation
248 */
249
250 public boolean hasNullMarker(Field f) {
251 if (f == null) {
252 throw new NullPointerException();
253 }
254 return hasNullMarker0(f);
255 }
256
257 private native boolean hasNullMarker0(Object o);
258
259 /* Returns the offset of the null marker of the field,
260 * or -1 if the field doesn't have a null marker
261 */
262
263 public int nullMarkerOffset(Field f) {
264 if (f == null) {
265 throw new NullPointerException();
266 }
267 return nullMarkerOffset0(f);
268 }
269
270 private native int nullMarkerOffset0(Object o);
271
272 public static final int NON_FLAT_LAYOUT = 0;
273
274 /* Reports the kind of layout used for an element in the storage
275 * allocation of the given array. Do not expect to perform any logic
276 * or layout control with this value, it is just an opaque token
277 * used for performance reasons.
278 *
279 * A layout of 0 indicates this array is not flat.
280 */
281 public int arrayLayout(Object[] array) {
282 if (array == null) {
283 throw new NullPointerException();
284 }
285 return arrayLayout0(array);
286 }
287
288 @IntrinsicCandidate
289 private native int arrayLayout0(Object[] array);
290
291
292 /* Reports the kind of layout used for a given field in the storage
293 * allocation of its class. Do not expect to perform any logic
294 * or layout control with this value, it is just an opaque token
295 * used for performance reasons.
296 *
297 * A layout of 0 indicates this field is not flat.
298 */
299 public int fieldLayout(Field f) {
300 if (f == null) {
301 throw new NullPointerException();
302 }
303 return fieldLayout0(f);
304 }
305
306 private native int fieldLayout0(Object o);
307
308 public native Object[] newSpecialArray(Class<?> componentType,
309 int length, int layoutKind);
310
311 /**
312 * Fetches a reference value from a given Java variable.
313 * This method can return a reference to either an object or value
314 * or a null reference.
315 *
316 * @see #getInt(Object, long)
317 */
318 @IntrinsicCandidate
319 public native Object getReference(Object o, long offset);
320
321 /**
322 * Stores a reference value into a given Java variable.
323 * This method can store a reference to either an object or value
324 * or a null reference.
325 * <p>
326 * Unless the reference {@code x} being stored is either null
327 * or matches the field type, the results are undefined.
328 * If the reference {@code o} is non-null, card marks or
329 * other store barriers for that object (if the VM requires them)
330 * are updated.
331 * @see #putInt(Object, long, int)
332 */
333 @IntrinsicCandidate
334 public native void putReference(Object o, long offset, Object x);
335
336 /**
337 * Fetches a value of type {@code <V>} from a given Java variable.
338 * More specifically, fetches a field or array element within the given
339 * {@code o} object at the given offset, or (if {@code o} is null)
340 * from the memory address whose numerical value is the given offset.
341 *
342 * @apiNote
343 * The returned object is newly allocated into the heap, because flat
344 * values lack object headers and thus can't be used as objects directly.
345 *
346 * @param o Java heap object in which the variable resides, if any, else
347 * null
348 * @param offset indication of where the variable resides in a Java heap
349 * object, if any, else a memory address locating the variable
350 * statically
351 * @param layoutKind opaque value used by the VM to know the layout
352 * the field or array element. This value must be retrieved with
353 * {@link #fieldLayout} or {@link #arrayLayout}.
354 * @param valueType value type
355 * @param <V> the type of a value
356 * @return the value fetched from the indicated Java variable
357 * @throws RuntimeException No defined exceptions are thrown, not even
358 * {@link NullPointerException}
359 */
360 @IntrinsicCandidate
361 public native <V> V getFlatValue(Object o, long offset, int layoutKind, Class<?> valueType);
362
363 /**
364 * Stores the given value into a given Java variable.
365 *
366 * Unless the reference {@code o} being stored is either null
367 * or matches the field type, the results are undefined.
368 *
369 * @param o Java heap object in which the variable resides, if any, else
370 * null
371 * @param offset indication of where the variable resides in a Java heap
372 * object, if any, else a memory address locating the variable
373 * statically
374 * @param layoutKind opaque value used by the VM to know the layout
375 * the field or array element. This value must be retrieved with
376 * {@link #fieldLayout} or {@link #arrayLayout}.
377 * @param valueType value type
378 * @param v the value to store into the indicated Java variable
379 * @param <V> the type of a value
380 * @throws RuntimeException No defined exceptions are thrown, not even
381 * {@link NullPointerException}
382 */
383 @IntrinsicCandidate
384 public native <V> void putFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, V v);
385
386 /**
387 * Returns the header size of the given value type.
388 *
389 * @param valueType value type
390 * @return the header size of the value type
391 */
392 public native <V> long valueHeaderSize(Class<V> valueType);
393
394 /** @see #getInt(Object, long) */
395 @IntrinsicCandidate
396 public native boolean getBoolean(Object o, long offset);
397
398 /** @see #putInt(Object, long, int) */
399 @IntrinsicCandidate
400 public native void putBoolean(Object o, long offset, boolean x);
401
402 /** @see #getInt(Object, long) */
403 @IntrinsicCandidate
404 public native byte getByte(Object o, long offset);
405
406 /** @see #putInt(Object, long, int) */
407 @IntrinsicCandidate
408 public native void putByte(Object o, long offset, byte x);
409
410 /** @see #getInt(Object, long) */
411 @IntrinsicCandidate
412 public native short getShort(Object o, long offset);
413
414 /** @see #putInt(Object, long, int) */
415 @IntrinsicCandidate
416 public native void putShort(Object o, long offset, short x);
417
418 /** @see #getInt(Object, long) */
419 @IntrinsicCandidate
420 public native char getChar(Object o, long offset);
421
422 /** @see #putInt(Object, long, int) */
423 @IntrinsicCandidate
424 public native void putChar(Object o, long offset, char x);
425
426 /** @see #getInt(Object, long) */
427 @IntrinsicCandidate
428 public native long getLong(Object o, long offset);
429
430 /** @see #putInt(Object, long, int) */
431 @IntrinsicCandidate
432 public native void putLong(Object o, long offset, long x);
433
434 /** @see #getInt(Object, long) */
435 @IntrinsicCandidate
436 public native float getFloat(Object o, long offset);
437
438 /** @see #putInt(Object, long, int) */
439 @IntrinsicCandidate
440 public native void putFloat(Object o, long offset, float x);
441
442 /** @see #getInt(Object, long) */
443 @IntrinsicCandidate
444 public native double getDouble(Object o, long offset);
445
446 /** @see #putInt(Object, long, int) */
447 @IntrinsicCandidate
448 public native void putDouble(Object o, long offset, double x);
449
450 /**
451 * Fetches a native pointer from a given memory address. If the address is
452 * zero, or does not point into a block obtained from {@link
453 * #allocateMemory}, the results are undefined.
454 *
455 * <p>If the native pointer is less than 64 bits wide, it is extended as
456 * an unsigned number to a Java long. The pointer may be indexed by any
457 * given byte offset, simply by adding that offset (as a simple integer) to
458 * the long representing the pointer. The number of bytes actually read
459 * from the target address may be determined by consulting {@link
460 * #addressSize}.
461 *
462 * @see #allocateMemory
463 * @see #getInt(Object, long)
464 */
465 @ForceInline
466 public long getAddress(Object o, long offset) {
467 if (ADDRESS_SIZE == 4) {
468 return Integer.toUnsignedLong(getInt(o, offset));
469 } else {
470 return getLong(o, offset);
471 }
472 }
473
474 /**
475 * Stores a native pointer into a given memory address. If the address is
476 * zero, or does not point into a block obtained from {@link
477 * #allocateMemory}, the results are undefined.
478 *
479 * <p>The number of bytes actually written at the target address may be
480 * determined by consulting {@link #addressSize}.
481 *
482 * @see #allocateMemory
483 * @see #putInt(Object, long, int)
484 */
485 @ForceInline
486 public void putAddress(Object o, long offset, long x) {
487 if (ADDRESS_SIZE == 4) {
488 putInt(o, offset, (int)x);
489 } else {
490 putLong(o, offset, x);
491 }
492 }
493
494 // These read VM internal data.
495
496 /**
497 * Fetches an uncompressed reference value from a given native variable
498 * ignoring the VM's compressed references mode.
499 *
500 * @param address a memory address locating the variable
501 * @return the value fetched from the indicated native variable
502 */
503 public native Object getUncompressedObject(long address);
504
505 // These work on values in the C heap.
506
507 /**
508 * Fetches a value from a given memory address. If the address is zero, or
509 * does not point into a block obtained from {@link #allocateMemory}, the
510 * results are undefined.
511 *
512 * @see #allocateMemory
513 */
514 @ForceInline
515 public byte getByte(long address) {
516 return getByte(null, address);
517 }
518
519 /**
520 * Stores a value into a given memory address. If the address is zero, or
521 * does not point into a block obtained from {@link #allocateMemory}, the
522 * results are undefined.
523 *
524 * @see #getByte(long)
525 */
526 @ForceInline
527 public void putByte(long address, byte x) {
528 putByte(null, address, x);
529 }
530
531 /** @see #getByte(long) */
532 @ForceInline
533 public short getShort(long address) {
534 return getShort(null, address);
535 }
536
537 /** @see #putByte(long, byte) */
538 @ForceInline
539 public void putShort(long address, short x) {
540 putShort(null, address, x);
541 }
542
543 /** @see #getByte(long) */
544 @ForceInline
545 public char getChar(long address) {
546 return getChar(null, address);
547 }
548
549 /** @see #putByte(long, byte) */
550 @ForceInline
551 public void putChar(long address, char x) {
552 putChar(null, address, x);
553 }
554
555 /** @see #getByte(long) */
556 @ForceInline
557 public int getInt(long address) {
558 return getInt(null, address);
559 }
560
561 /** @see #putByte(long, byte) */
562 @ForceInline
563 public void putInt(long address, int x) {
564 putInt(null, address, x);
565 }
566
567 /** @see #getByte(long) */
568 @ForceInline
569 public long getLong(long address) {
570 return getLong(null, address);
571 }
572
573 /** @see #putByte(long, byte) */
574 @ForceInline
575 public void putLong(long address, long x) {
576 putLong(null, address, x);
577 }
578
579 /** @see #getByte(long) */
580 @ForceInline
581 public float getFloat(long address) {
582 return getFloat(null, address);
583 }
584
585 /** @see #putByte(long, byte) */
586 @ForceInline
587 public void putFloat(long address, float x) {
588 putFloat(null, address, x);
589 }
590
591 /** @see #getByte(long) */
592 @ForceInline
593 public double getDouble(long address) {
594 return getDouble(null, address);
595 }
596
597 /** @see #putByte(long, byte) */
598 @ForceInline
599 public void putDouble(long address, double x) {
600 putDouble(null, address, x);
601 }
602
603 /** @see #getAddress(Object, long) */
604 @ForceInline
605 public long getAddress(long address) {
606 return getAddress(null, address);
607 }
608
609 /** @see #putAddress(Object, long, long) */
610 @ForceInline
611 public void putAddress(long address, long x) {
612 putAddress(null, address, x);
613 }
614
615
616
617 //--- helper methods for validating various types of objects/values
618
619 /**
620 * Create an exception reflecting that some of the input was invalid
621 *
622 * <em>Note:</em> It is the responsibility of the caller to make
623 * sure arguments are checked before the methods are called. While
624 * some rudimentary checks are performed on the input, the checks
625 * are best effort and when performance is an overriding priority,
626 * as when methods of this class are optimized by the runtime
627 * compiler, some or all checks (if any) may be elided. Hence, the
628 * caller must not rely on the checks and corresponding
629 * exceptions!
630 *
631 * @return an exception object
632 */
633 private RuntimeException invalidInput() {
634 return new IllegalArgumentException();
635 }
636
637 /**
638 * Check if a value is 32-bit clean (32 MSB are all zero)
639 *
640 * @param value the 64-bit value to check
641 *
642 * @return true if the value is 32-bit clean
643 */
644 private boolean is32BitClean(long value) {
645 return value >>> 32 == 0;
646 }
647
648 /**
649 * Check the validity of a size (the equivalent of a size_t)
650 *
651 * @throws RuntimeException if the size is invalid
652 * (<em>Note:</em> after optimization, invalid inputs may
653 * go undetected, which will lead to unpredictable
654 * behavior)
655 */
656 private void checkSize(long size) {
657 if (ADDRESS_SIZE == 4) {
658 // Note: this will also check for negative sizes
659 if (!is32BitClean(size)) {
660 throw invalidInput();
661 }
662 } else if (size < 0) {
663 throw invalidInput();
664 }
665 }
666
667 /**
668 * Check the validity of a native address (the equivalent of void*)
669 *
670 * @throws RuntimeException if the address is invalid
671 * (<em>Note:</em> after optimization, invalid inputs may
672 * go undetected, which will lead to unpredictable
673 * behavior)
674 */
675 private void checkNativeAddress(long address) {
676 if (ADDRESS_SIZE == 4) {
677 // Accept both zero and sign extended pointers. A valid
678 // pointer will, after the +1 below, either have produced
679 // the value 0x0 or 0x1. Masking off the low bit allows
680 // for testing against 0.
681 if ((((address >> 32) + 1) & ~1) != 0) {
682 throw invalidInput();
683 }
684 }
685 }
686
687 /**
688 * Check the validity of an offset, relative to a base object
689 *
690 * @param o the base object
691 * @param offset the offset to check
692 *
693 * @throws RuntimeException if the size is invalid
694 * (<em>Note:</em> after optimization, invalid inputs may
695 * go undetected, which will lead to unpredictable
696 * behavior)
697 */
698 private void checkOffset(Object o, long offset) {
699 if (ADDRESS_SIZE == 4) {
700 // Note: this will also check for negative offsets
701 if (!is32BitClean(offset)) {
702 throw invalidInput();
703 }
704 } else if (offset < 0) {
705 throw invalidInput();
706 }
707 }
708
709 /**
710 * Check the validity of a double-register pointer
711 *
712 * Note: This code deliberately does *not* check for NPE for (at
713 * least) three reasons:
714 *
715 * 1) NPE is not just NULL/0 - there is a range of values all
716 * resulting in an NPE, which is not trivial to check for
717 *
718 * 2) It is the responsibility of the callers of Unsafe methods
719 * to verify the input, so throwing an exception here is not really
720 * useful - passing in a NULL pointer is a critical error and the
721 * must not expect an exception to be thrown anyway.
722 *
723 * 3) the actual operations will detect NULL pointers anyway by
724 * means of traps and signals (like SIGSEGV).
725 *
726 * @param o Java heap object, or null
727 * @param offset indication of where the variable resides in a Java heap
728 * object, if any, else a memory address locating the variable
729 * statically
730 *
731 * @throws RuntimeException if the pointer is invalid
732 * (<em>Note:</em> after optimization, invalid inputs may
733 * go undetected, which will lead to unpredictable
734 * behavior)
735 */
736 private void checkPointer(Object o, long offset) {
737 if (o == null) {
738 checkNativeAddress(offset);
739 } else {
740 checkOffset(o, offset);
741 }
742 }
743
744 /**
745 * Check if a type is a primitive array type
746 *
747 * @param c the type to check
748 *
749 * @return true if the type is a primitive array type
750 */
751 private void checkPrimitiveArray(Class<?> c) {
752 Class<?> componentType = c.getComponentType();
753 if (componentType == null || !componentType.isPrimitive()) {
754 throw invalidInput();
755 }
756 }
757
758 /**
759 * Check that a pointer is a valid primitive array type pointer
760 *
761 * Note: pointers off-heap are considered to be primitive arrays
762 *
763 * @throws RuntimeException if the pointer is invalid
764 * (<em>Note:</em> after optimization, invalid inputs may
765 * go undetected, which will lead to unpredictable
766 * behavior)
767 */
768 private void checkPrimitivePointer(Object o, long offset) {
769 checkPointer(o, offset);
770
771 if (o != null) {
772 // If on heap, it must be a primitive array
773 checkPrimitiveArray(o.getClass());
774 }
775 }
776
777
778 //--- wrappers for malloc, realloc, free:
779
780 /**
781 * Round up allocation size to a multiple of HeapWordSize.
782 */
783 private long alignToHeapWordSize(long bytes) {
784 if (bytes >= 0) {
785 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1);
786 } else {
787 throw invalidInput();
788 }
789 }
790
791 /**
792 * Allocates a new block of native memory, of the given size in bytes. The
793 * contents of the memory are uninitialized; they will generally be
794 * garbage. The resulting native pointer will be zero if and only if the
795 * requested size is zero. The resulting native pointer will be aligned for
796 * all value types. Dispose of this memory by calling {@link #freeMemory}
797 * or resize it with {@link #reallocateMemory}.
798 *
799 * <em>Note:</em> It is the responsibility of the caller to make
800 * sure arguments are checked before the methods are called. While
801 * some rudimentary checks are performed on the input, the checks
802 * are best effort and when performance is an overriding priority,
803 * as when methods of this class are optimized by the runtime
804 * compiler, some or all checks (if any) may be elided. Hence, the
805 * caller must not rely on the checks and corresponding
806 * exceptions!
807 *
808 * @throws RuntimeException if the size is negative or too large
809 * for the native size_t type
810 *
811 * @throws OutOfMemoryError if the allocation is refused by the system
812 *
813 * @see #getByte(long)
814 * @see #putByte(long, byte)
815 */
816 public long allocateMemory(long bytes) {
817 bytes = alignToHeapWordSize(bytes);
818
819 allocateMemoryChecks(bytes);
820
821 if (bytes == 0) {
822 return 0;
823 }
824
825 long p = allocateMemory0(bytes);
826 if (p == 0) {
827 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
828 }
829
830 return p;
831 }
832
833 /**
834 * Validate the arguments to allocateMemory
835 *
836 * @throws RuntimeException if the arguments are invalid
837 * (<em>Note:</em> after optimization, invalid inputs may
838 * go undetected, which will lead to unpredictable
839 * behavior)
840 */
841 private void allocateMemoryChecks(long bytes) {
842 checkSize(bytes);
843 }
844
845 /**
846 * Resizes a new block of native memory, to the given size in bytes. The
847 * contents of the new block past the size of the old block are
848 * uninitialized; they will generally be garbage. The resulting native
849 * pointer will be zero if and only if the requested size is zero. The
850 * resulting native pointer will be aligned for all value types. Dispose
851 * of this memory by calling {@link #freeMemory}, or resize it with {@link
852 * #reallocateMemory}. The address passed to this method may be null, in
853 * which case an allocation will be performed.
854 *
855 * <em>Note:</em> It is the responsibility of the caller to make
856 * sure arguments are checked before the methods are called. While
857 * some rudimentary checks are performed on the input, the checks
858 * are best effort and when performance is an overriding priority,
859 * as when methods of this class are optimized by the runtime
860 * compiler, some or all checks (if any) may be elided. Hence, the
861 * caller must not rely on the checks and corresponding
862 * exceptions!
863 *
864 * @throws RuntimeException if the size is negative or too large
865 * for the native size_t type
866 *
867 * @throws OutOfMemoryError if the allocation is refused by the system
868 *
869 * @see #allocateMemory
870 */
871 public long reallocateMemory(long address, long bytes) {
872 bytes = alignToHeapWordSize(bytes);
873
874 reallocateMemoryChecks(address, bytes);
875
876 if (bytes == 0) {
877 freeMemory(address);
878 return 0;
879 }
880
881 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes);
882 if (p == 0) {
883 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes");
884 }
885
886 return p;
887 }
888
889 /**
890 * Validate the arguments to reallocateMemory
891 *
892 * @throws RuntimeException if the arguments are invalid
893 * (<em>Note:</em> after optimization, invalid inputs may
894 * go undetected, which will lead to unpredictable
895 * behavior)
896 */
897 private void reallocateMemoryChecks(long address, long bytes) {
898 checkPointer(null, address);
899 checkSize(bytes);
900 }
901
902 /**
903 * Sets all bytes in a given block of memory to a fixed value
904 * (usually zero).
905 *
906 * <p>This method determines a block's base address by means of two parameters,
907 * and so it provides (in effect) a <em>double-register</em> addressing mode,
908 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
909 * the offset supplies an absolute base address.
910 *
911 * <p>The stores are in coherent (atomic) units of a size determined
912 * by the address and length parameters. If the effective address and
913 * length are all even modulo 8, the stores take place in 'long' units.
914 * If the effective address and length are (resp.) even modulo 4 or 2,
915 * the stores take place in units of 'int' or 'short'.
916 *
917 * <em>Note:</em> It is the responsibility of the caller to make
918 * sure arguments are checked before the methods are called. While
919 * some rudimentary checks are performed on the input, the checks
920 * are best effort and when performance is an overriding priority,
921 * as when methods of this class are optimized by the runtime
922 * compiler, some or all checks (if any) may be elided. Hence, the
923 * caller must not rely on the checks and corresponding
924 * exceptions!
925 *
926 * @throws RuntimeException if any of the arguments is invalid
927 *
928 * @since 1.7
929 */
930 public void setMemory(Object o, long offset, long bytes, byte value) {
931 setMemoryChecks(o, offset, bytes, value);
932
933 if (bytes == 0) {
934 return;
935 }
936
937 setMemory0(o, offset, bytes, value);
938 }
939
940 /**
941 * Sets all bytes in a given block of memory to a fixed value
942 * (usually zero). This provides a <em>single-register</em> addressing mode,
943 * as discussed in {@link #getInt(Object,long)}.
944 *
945 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}.
946 */
947 public void setMemory(long address, long bytes, byte value) {
948 setMemory(null, address, bytes, value);
949 }
950
951 /**
952 * Validate the arguments to setMemory
953 *
954 * @throws RuntimeException if the arguments are invalid
955 * (<em>Note:</em> after optimization, invalid inputs may
956 * go undetected, which will lead to unpredictable
957 * behavior)
958 */
959 private void setMemoryChecks(Object o, long offset, long bytes, byte value) {
960 checkPrimitivePointer(o, offset);
961 checkSize(bytes);
962 }
963
964 /**
965 * Sets all bytes in a given block of memory to a copy of another
966 * block.
967 *
968 * <p>This method determines each block's base address by means of two parameters,
969 * and so it provides (in effect) a <em>double-register</em> addressing mode,
970 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
971 * the offset supplies an absolute base address.
972 *
973 * <p>The transfers are in coherent (atomic) units of a size determined
974 * by the address and length parameters. If the effective addresses and
975 * length are all even modulo 8, the transfer takes place in 'long' units.
976 * If the effective addresses and length are (resp.) even modulo 4 or 2,
977 * the transfer takes place in units of 'int' or 'short'.
978 *
979 * <em>Note:</em> It is the responsibility of the caller to make
980 * sure arguments are checked before the methods are called. While
981 * some rudimentary checks are performed on the input, the checks
982 * are best effort and when performance is an overriding priority,
983 * as when methods of this class are optimized by the runtime
984 * compiler, some or all checks (if any) may be elided. Hence, the
985 * caller must not rely on the checks and corresponding
986 * exceptions!
987 *
988 * @throws RuntimeException if any of the arguments is invalid
989 *
990 * @since 1.7
991 */
992 public void copyMemory(Object srcBase, long srcOffset,
993 Object destBase, long destOffset,
994 long bytes) {
995 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes);
996
997 if (bytes == 0) {
998 return;
999 }
1000
1001 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes);
1002 }
1003
1004 /**
1005 * Sets all bytes in a given block of memory to a copy of another
1006 * block. This provides a <em>single-register</em> addressing mode,
1007 * as discussed in {@link #getInt(Object,long)}.
1008 *
1009 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}.
1010 */
1011 public void copyMemory(long srcAddress, long destAddress, long bytes) {
1012 copyMemory(null, srcAddress, null, destAddress, bytes);
1013 }
1014
1015 /**
1016 * Validate the arguments to copyMemory
1017 *
1018 * @throws RuntimeException if any of the arguments is invalid
1019 * (<em>Note:</em> after optimization, invalid inputs may
1020 * go undetected, which will lead to unpredictable
1021 * behavior)
1022 */
1023 private void copyMemoryChecks(Object srcBase, long srcOffset,
1024 Object destBase, long destOffset,
1025 long bytes) {
1026 checkSize(bytes);
1027 checkPrimitivePointer(srcBase, srcOffset);
1028 checkPrimitivePointer(destBase, destOffset);
1029 }
1030
1031 /**
1032 * Copies all elements from one block of memory to another block,
1033 * *unconditionally* byte swapping the elements on the fly.
1034 *
1035 * <p>This method determines each block's base address by means of two parameters,
1036 * and so it provides (in effect) a <em>double-register</em> addressing mode,
1037 * as discussed in {@link #getInt(Object,long)}. When the object reference is null,
1038 * the offset supplies an absolute base address.
1039 *
1040 * <em>Note:</em> It is the responsibility of the caller to make
1041 * sure arguments are checked before the methods are called. While
1042 * some rudimentary checks are performed on the input, the checks
1043 * are best effort and when performance is an overriding priority,
1044 * as when methods of this class are optimized by the runtime
1045 * compiler, some or all checks (if any) may be elided. Hence, the
1046 * caller must not rely on the checks and corresponding
1047 * exceptions!
1048 *
1049 * @throws RuntimeException if any of the arguments is invalid
1050 *
1051 * @since 9
1052 */
1053 public void copySwapMemory(Object srcBase, long srcOffset,
1054 Object destBase, long destOffset,
1055 long bytes, long elemSize) {
1056 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1057
1058 if (bytes == 0) {
1059 return;
1060 }
1061
1062 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize);
1063 }
1064
1065 private void copySwapMemoryChecks(Object srcBase, long srcOffset,
1066 Object destBase, long destOffset,
1067 long bytes, long elemSize) {
1068 checkSize(bytes);
1069
1070 if (elemSize != 2 && elemSize != 4 && elemSize != 8) {
1071 throw invalidInput();
1072 }
1073 if (bytes % elemSize != 0) {
1074 throw invalidInput();
1075 }
1076
1077 checkPrimitivePointer(srcBase, srcOffset);
1078 checkPrimitivePointer(destBase, destOffset);
1079 }
1080
1081 /**
1082 * Copies all elements from one block of memory to another block, byte swapping the
1083 * elements on the fly.
1084 *
1085 * This provides a <em>single-register</em> addressing mode, as
1086 * discussed in {@link #getInt(Object,long)}.
1087 *
1088 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}.
1089 */
1090 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) {
1091 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize);
1092 }
1093
1094 /**
1095 * Disposes of a block of native memory, as obtained from {@link
1096 * #allocateMemory} or {@link #reallocateMemory}. The address passed to
1097 * this method may be null, in which case no action is taken.
1098 *
1099 * <em>Note:</em> It is the responsibility of the caller to make
1100 * sure arguments are checked before the methods are called. While
1101 * some rudimentary checks are performed on the input, the checks
1102 * are best effort and when performance is an overriding priority,
1103 * as when methods of this class are optimized by the runtime
1104 * compiler, some or all checks (if any) may be elided. Hence, the
1105 * caller must not rely on the checks and corresponding
1106 * exceptions!
1107 *
1108 * @throws RuntimeException if any of the arguments is invalid
1109 *
1110 * @see #allocateMemory
1111 */
1112 public void freeMemory(long address) {
1113 freeMemoryChecks(address);
1114
1115 if (address == 0) {
1116 return;
1117 }
1118
1119 freeMemory0(address);
1120 }
1121
1122 /**
1123 * Validate the arguments to freeMemory
1124 *
1125 * @throws RuntimeException if the arguments are invalid
1126 * (<em>Note:</em> after optimization, invalid inputs may
1127 * go undetected, which will lead to unpredictable
1128 * behavior)
1129 */
1130 private void freeMemoryChecks(long address) {
1131 checkPointer(null, address);
1132 }
1133
1134 /**
1135 * Ensure writeback of a specified virtual memory address range
1136 * from cache to physical memory. All bytes in the address range
1137 * are guaranteed to have been written back to physical memory on
1138 * return from this call i.e. subsequently executed store
1139 * instructions are guaranteed not to be visible before the
1140 * writeback is completed.
1141 *
1142 * @param address
1143 * the lowest byte address that must be guaranteed written
1144 * back to memory. bytes at lower addresses may also be
1145 * written back.
1146 *
1147 * @param length
1148 * the length in bytes of the region starting at address
1149 * that must be guaranteed written back to memory.
1150 *
1151 * @throws RuntimeException if memory writeback is not supported
1152 * on the current hardware of if the arguments are invalid.
1153 * (<em>Note:</em> after optimization, invalid inputs may
1154 * go undetected, which will lead to unpredictable
1155 * behavior)
1156 *
1157 * @since 14
1158 */
1159
1160 public void writebackMemory(long address, long length) {
1161 checkWritebackEnabled();
1162 checkWritebackMemory(address, length);
1163
1164 // perform any required pre-writeback barrier
1165 writebackPreSync0();
1166
1167 // write back one cache line at a time
1168 long line = dataCacheLineAlignDown(address);
1169 long end = address + length;
1170 while (line < end) {
1171 writeback0(line);
1172 line += dataCacheLineFlushSize();
1173 }
1174
1175 // perform any required post-writeback barrier
1176 writebackPostSync0();
1177 }
1178
1179 /**
1180 * Validate the arguments to writebackMemory
1181 *
1182 * @throws RuntimeException if the arguments are invalid
1183 * (<em>Note:</em> after optimization, invalid inputs may
1184 * go undetected, which will lead to unpredictable
1185 * behavior)
1186 */
1187 private void checkWritebackMemory(long address, long length) {
1188 checkNativeAddress(address);
1189 checkSize(length);
1190 }
1191
1192 /**
1193 * Validate that the current hardware supports memory writeback.
1194 * (<em>Note:</em> this is a belt and braces check. Clients are
1195 * expected to test whether writeback is enabled by calling
1196 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid
1197 * calling method {@link writeback #writeback} if it is disabled).
1198 *
1199 *
1200 * @throws RuntimeException if memory writeback is not supported
1201 */
1202 private void checkWritebackEnabled() {
1203 if (!isWritebackEnabled()) {
1204 throw new RuntimeException("writebackMemory not enabled!");
1205 }
1206 }
1207
1208 /**
1209 * force writeback of an individual cache line.
1210 *
1211 * @param address
1212 * the start address of the cache line to be written back
1213 */
1214 @IntrinsicCandidate
1215 private native void writeback0(long address);
1216
1217 /**
1218 * Serialize writeback operations relative to preceding memory writes.
1219 */
1220 @IntrinsicCandidate
1221 private native void writebackPreSync0();
1222
1223 /**
1224 * Serialize writeback operations relative to following memory writes.
1225 */
1226 @IntrinsicCandidate
1227 private native void writebackPostSync0();
1228
1229 //--- random queries
1230
1231 /**
1232 * This constant differs from all results that will ever be returned from
1233 * {@link #staticFieldOffset}, {@link #objectFieldOffset},
1234 * or {@link #arrayBaseOffset}.
1235 * <p>
1236 * The static type is @code long} to emphasize that long arithmetic should
1237 * always be used for offset calculations to avoid overflows.
1238 */
1239 public static final long INVALID_FIELD_OFFSET = -1;
1240
1241 /**
1242 * Reports the location of a given field in the storage allocation of its
1243 * class. Do not expect to perform any sort of arithmetic on this offset;
1244 * it is just a cookie which is passed to the unsafe heap memory accessors.
1245 *
1246 * <p>Any given field will always have the same offset and base, and no
1247 * two distinct fields of the same class will ever have the same offset
1248 * and base.
1249 *
1250 * <p>As of 1.4.1, offsets for fields are represented as long values,
1251 * although the Sun JVM does not use the most significant 32 bits.
1252 * However, JVM implementations which store static fields at absolute
1253 * addresses can use long offsets and null base pointers to express
1254 * the field locations in a form usable by {@link #getInt(Object,long)}.
1255 * Therefore, code which will be ported to such JVMs on 64-bit platforms
1256 * must preserve all bits of static field offsets.
1257 *
1258 * @throws NullPointerException if the field is {@code null}
1259 * @throws IllegalArgumentException if the field is static
1260 * @see #getInt(Object, long)
1261 */
1262 public long objectFieldOffset(Field f) {
1263 if (f == null) {
1264 throw new NullPointerException();
1265 }
1266
1267 return objectFieldOffset0(f);
1268 }
1269
1270 /**
1271 * (For compile-time known instance fields in JDK code only) Reports the
1272 * location of the field with a given name in the storage allocation of its
1273 * class.
1274 * <p>
1275 * This API is used to avoid creating reflective Objects in Java code at
1276 * startup. This should not be used to find fields in non-trusted code.
1277 * Use the {@link #objectFieldOffset(Field) Field}-accepting version for
1278 * arbitrary fields instead.
1279 *
1280 * @throws NullPointerException if any parameter is {@code null}.
1281 * @throws InternalError if the presumably known field couldn't be found
1282 *
1283 * @see #objectFieldOffset(Field)
1284 */
1285 public long objectFieldOffset(Class<?> c, String name) {
1286 if (c == null || name == null) {
1287 throw new NullPointerException();
1288 }
1289
1290 long result = knownObjectFieldOffset0(c, name);
1291 if (result < 0) {
1292 String type = switch ((int) result) {
1293 case -2 -> "a static field";
1294 case -1 -> "not found";
1295 default -> "unknown";
1296 };
1297 throw new InternalError("Field %s.%s %s".formatted(c.getTypeName(), name, type));
1298 }
1299 return result;
1300 }
1301
1302 /**
1303 * Reports the location of a given static field, in conjunction with {@link
1304 * #staticFieldBase}.
1305 * <p>Do not expect to perform any sort of arithmetic on this offset;
1306 * it is just a cookie which is passed to the unsafe heap memory accessors.
1307 *
1308 * <p>Any given field will always have the same offset, and no two distinct
1309 * fields of the same class will ever have the same offset.
1310 *
1311 * <p>As of 1.4.1, offsets for fields are represented as long values,
1312 * although the Sun JVM does not use the most significant 32 bits.
1313 * It is hard to imagine a JVM technology which needs more than
1314 * a few bits to encode an offset within a non-array object,
1315 * However, for consistency with other methods in this class,
1316 * this method reports its result as a long value.
1317 *
1318 * @throws NullPointerException if the field is {@code null}
1319 * @throws IllegalArgumentException if the field is not static
1320 * @see #getInt(Object, long)
1321 */
1322 public long staticFieldOffset(Field f) {
1323 if (f == null) {
1324 throw new NullPointerException();
1325 }
1326
1327 return staticFieldOffset0(f);
1328 }
1329
1330 /**
1331 * Reports the location of a given static field, in conjunction with {@link
1332 * #staticFieldOffset}.
1333 * <p>Fetch the base "Object", if any, with which static fields of the
1334 * given class can be accessed via methods like {@link #getInt(Object,
1335 * long)}. This value may be null. This value may refer to an object
1336 * which is a "cookie", not guaranteed to be a real Object, and it should
1337 * not be used in any way except as argument to the get and put routines in
1338 * this class.
1339 *
1340 * @throws NullPointerException if the field is {@code null}
1341 * @throws IllegalArgumentException if the field is not static
1342 */
1343 public Object staticFieldBase(Field f) {
1344 if (f == null) {
1345 throw new NullPointerException();
1346 }
1347
1348 return staticFieldBase0(f);
1349 }
1350
1351 /**
1352 * Detects if the given class may need to be initialized. This is often
1353 * needed in conjunction with obtaining the static field base of a
1354 * class.
1355 * @return false only if a call to {@code ensureClassInitialized} would have no effect
1356 */
1357 public boolean shouldBeInitialized(Class<?> c) {
1358 if (c == null) {
1359 throw new NullPointerException();
1360 }
1361
1362 return shouldBeInitialized0(c);
1363 }
1364
1365 /**
1366 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1367 * This is often needed in conjunction with obtaining the static field base
1368 * of a class.
1369 *
1370 * The call returns when either class {@code c} is fully initialized or
1371 * class {@code c} is being initialized and the call is performed from
1372 * the initializing thread. In the latter case a subsequent call to
1373 * {@link #shouldBeInitialized} will return {@code true}.
1374 */
1375 public void ensureClassInitialized(Class<?> c) {
1376 if (c == null) {
1377 throw new NullPointerException();
1378 }
1379
1380 ensureClassInitialized0(c);
1381 }
1382
1383 /**
1384 * The reading or writing of strict static fields may require
1385 * special processing. Notify the VM that such an event is about
1386 * to happen. The VM may respond by throwing an exception, in the
1387 * case of a read of an uninitialized field. If the VM allows the
1388 * method to return normally, no further calls are needed, with
1389 * the same arguments.
1390 */
1391 public void notifyStrictStaticAccess(Class<?> c, long staticFieldOffset, boolean writing) {
1392 if (c == null) {
1393 throw new NullPointerException();
1394 }
1395 notifyStrictStaticAccess0(c, staticFieldOffset, writing);
1396 }
1397
1398 /**
1399 * Reports the offset of the first element in the storage allocation of a
1400 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1401 * for the same class, you may use that scale factor, together with this
1402 * base offset, to form new offsets to access elements of arrays of the
1403 * given class.
1404 * <p>
1405 * The return value is in the range of a {@code int}. The return type is
1406 * {@code long} to emphasize that long arithmetic should always be used
1407 * for offset calculations to avoid overflows.
1408 * <p>
1409 * This method doesn't support arrays with an element type that is
1410 * a value class, because this type of array can have multiple layouts.
1411 * For these arrays, {@code arrayInstanceBaseOffset(Object[] array)}
1412 * must be used instead.
1413 *
1414 * @see #getInt(Object, long)
1415 * @see #putInt(Object, long, int)
1416 */
1417 public long arrayBaseOffset(Class<?> arrayClass) {
1418 if (arrayClass == null) {
1419 throw new NullPointerException();
1420 }
1421
1422 return arrayBaseOffset0(arrayClass);
1423 }
1424
1425 public long arrayInstanceBaseOffset(Object[] array) {
1426 if (array == null) {
1427 throw new NullPointerException();
1428 }
1429
1430 return arrayInstanceBaseOffset0(array);
1431 }
1432
1433 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1434 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1435 = theUnsafe.arrayBaseOffset(boolean[].class);
1436
1437 /** The value of {@code arrayBaseOffset(byte[].class)} */
1438 public static final long ARRAY_BYTE_BASE_OFFSET
1439 = theUnsafe.arrayBaseOffset(byte[].class);
1440
1441 /** The value of {@code arrayBaseOffset(short[].class)} */
1442 public static final long ARRAY_SHORT_BASE_OFFSET
1443 = theUnsafe.arrayBaseOffset(short[].class);
1444
1445 /** The value of {@code arrayBaseOffset(char[].class)} */
1446 public static final long ARRAY_CHAR_BASE_OFFSET
1447 = theUnsafe.arrayBaseOffset(char[].class);
1448
1449 /** The value of {@code arrayBaseOffset(int[].class)} */
1450 public static final long ARRAY_INT_BASE_OFFSET
1451 = theUnsafe.arrayBaseOffset(int[].class);
1452
1453 /** The value of {@code arrayBaseOffset(long[].class)} */
1454 public static final long ARRAY_LONG_BASE_OFFSET
1455 = theUnsafe.arrayBaseOffset(long[].class);
1456
1457 /** The value of {@code arrayBaseOffset(float[].class)} */
1458 public static final long ARRAY_FLOAT_BASE_OFFSET
1459 = theUnsafe.arrayBaseOffset(float[].class);
1460
1461 /** The value of {@code arrayBaseOffset(double[].class)} */
1462 public static final long ARRAY_DOUBLE_BASE_OFFSET
1463 = theUnsafe.arrayBaseOffset(double[].class);
1464
1465 /** The value of {@code arrayBaseOffset(Object[].class)} */
1466 public static final long ARRAY_OBJECT_BASE_OFFSET
1467 = theUnsafe.arrayBaseOffset(Object[].class);
1468
1469 /**
1470 * Reports the scale factor for addressing elements in the storage
1471 * allocation of a given array class. However, arrays of "narrow" types
1472 * will generally not work properly with accessors like {@link
1473 * #getByte(Object, long)}, so the scale factor for such classes is reported
1474 * as zero.
1475 * <p>
1476 * The computation of the actual memory offset should always use {@code
1477 * long} arithmetic to avoid overflows.
1478 * <p>
1479 * This method doesn't support arrays with an element type that is
1480 * a value class, because this type of array can have multiple layouts.
1481 * For these arrays, {@code arrayInstanceIndexScale(Object[] array)}
1482 * must be used instead.
1483 *
1484 * @see #arrayBaseOffset
1485 * @see #getInt(Object, long)
1486 * @see #putInt(Object, long, int)
1487 */
1488 public int arrayIndexScale(Class<?> arrayClass) {
1489 if (arrayClass == null) {
1490 throw new NullPointerException();
1491 }
1492
1493 return arrayIndexScale0(arrayClass);
1494 }
1495
1496 public int arrayInstanceIndexScale(Object[] array) {
1497 if (array == null) {
1498 throw new NullPointerException();
1499 }
1500
1501 return arrayInstanceIndexScale0(array);
1502 }
1503
1504 /**
1505 * Returns the acmp map of this class, which must be a concrete value class.
1506 * Intended to be used by substitutability test in ValueObjectMethods only.
1507 * The format is subject to change.
1508 */
1509 public int[] getFieldMap(Class<?> c) {
1510 if (c == null) {
1511 throw new NullPointerException();
1512 }
1513 return getFieldMap0(c);
1514 }
1515
1516 /**
1517 * For a field of type {@code c}, returns true if and only if there is
1518 * a possible flat layout that contains no oop.
1519 * Required for numerical CAS safety.
1520 */
1521 public boolean isFlatPayloadBinary(Class<?> c) {
1522 int[] map = getFieldMap(c);
1523 int nbNonRef = map[0];
1524 return nbNonRef * 2 + 1 == map.length;
1525 }
1526
1527 /**
1528 * Return the size of the object in the heap.
1529 * @param o an object
1530 * @return the objects's size
1531 * @since Valhalla
1532 */
1533 public long getObjectSize(Object o) {
1534 if (o == null)
1535 throw new NullPointerException();
1536 return getObjectSize0(o);
1537 }
1538
1539 /** The value of {@code arrayIndexScale(boolean[].class)} */
1540 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1541 = theUnsafe.arrayIndexScale(boolean[].class);
1542
1543 /** The value of {@code arrayIndexScale(byte[].class)} */
1544 public static final int ARRAY_BYTE_INDEX_SCALE
1545 = theUnsafe.arrayIndexScale(byte[].class);
1546
1547 /** The value of {@code arrayIndexScale(short[].class)} */
1548 public static final int ARRAY_SHORT_INDEX_SCALE
1549 = theUnsafe.arrayIndexScale(short[].class);
1550
1551 /** The value of {@code arrayIndexScale(char[].class)} */
1552 public static final int ARRAY_CHAR_INDEX_SCALE
1553 = theUnsafe.arrayIndexScale(char[].class);
1554
1555 /** The value of {@code arrayIndexScale(int[].class)} */
1556 public static final int ARRAY_INT_INDEX_SCALE
1557 = theUnsafe.arrayIndexScale(int[].class);
1558
1559 /** The value of {@code arrayIndexScale(long[].class)} */
1560 public static final int ARRAY_LONG_INDEX_SCALE
1561 = theUnsafe.arrayIndexScale(long[].class);
1562
1563 /** The value of {@code arrayIndexScale(float[].class)} */
1564 public static final int ARRAY_FLOAT_INDEX_SCALE
1565 = theUnsafe.arrayIndexScale(float[].class);
1566
1567 /** The value of {@code arrayIndexScale(double[].class)} */
1568 public static final int ARRAY_DOUBLE_INDEX_SCALE
1569 = theUnsafe.arrayIndexScale(double[].class);
1570
1571 /** The value of {@code arrayIndexScale(Object[].class)} */
1572 public static final int ARRAY_OBJECT_INDEX_SCALE
1573 = theUnsafe.arrayIndexScale(Object[].class);
1574
1575 /**
1576 * Reports the size in bytes of a native pointer, as stored via {@link
1577 * #putAddress}. This value will be either 4 or 8. Note that the sizes of
1578 * other primitive types (as stored in native memory blocks) is determined
1579 * fully by their information content.
1580 */
1581 public int addressSize() {
1582 return ADDRESS_SIZE;
1583 }
1584
1585 /** The value of {@code addressSize()} */
1586 public static final int ADDRESS_SIZE = ADDRESS_SIZE0;
1587
1588 /**
1589 * Reports the size in bytes of a native memory page (whatever that is).
1590 * This value will always be a power of two.
1591 */
1592 public int pageSize() { return PAGE_SIZE; }
1593
1594 /**
1595 * Reports the size in bytes of a data cache line written back by
1596 * the hardware cache line flush operation available to the JVM or
1597 * 0 if data cache line flushing is not enabled.
1598 */
1599 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; }
1600
1601 /**
1602 * Rounds down address to a data cache line boundary as
1603 * determined by {@link #dataCacheLineFlushSize}
1604 * @return the rounded down address
1605 */
1606 public long dataCacheLineAlignDown(long address) {
1607 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1));
1608 }
1609
1610 /**
1611 * Returns true if data cache line writeback
1612 */
1613 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; }
1614
1615 //--- random trusted operations from JNI:
1616
1617 /**
1618 * Tells the VM to define a class, without security checks. By default, the
1619 * class loader and protection domain come from the caller's class.
1620 */
1621 public Class<?> defineClass(String name, byte[] b, int off, int len,
1622 ClassLoader loader,
1623 ProtectionDomain protectionDomain) {
1624 if (b == null) {
1625 throw new NullPointerException();
1626 }
1627 if (len < 0) {
1628 throw new ArrayIndexOutOfBoundsException();
1629 }
1630
1631 return defineClass0(name, b, off, len, loader, protectionDomain);
1632 }
1633
1634 public native Class<?> defineClass0(String name, byte[] b, int off, int len,
1635 ClassLoader loader,
1636 ProtectionDomain protectionDomain);
1637
1638 /**
1639 * Allocates an instance but does not run any constructor.
1640 * Initializes the class if it has not yet been.
1641 * <p>
1642 * This method returns an uninitialized instance. In general, this is undefined behavior, this
1643 * method is treated specially by the JVM to allow this behavior. The returned value must be
1644 * passed into a constructor using {@link MethodHandle#linkToSpecial} before any other
1645 * operation can be performed on it. Otherwise, the program is ill-formed.
1646 */
1647 @IntrinsicCandidate
1648 public native Object allocateInstance(Class<?> cls)
1649 throws InstantiationException;
1650
1651 /**
1652 * Allocates an array of a given type, but does not do zeroing.
1653 * <p>
1654 * This method should only be used in the very rare cases where a high-performance code
1655 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination.
1656 * In an overwhelming majority of cases, a normal Java allocation should be used instead.
1657 * <p>
1658 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents
1659 * before allowing untrusted code, or code in other threads, to observe the reference
1660 * to the newly allocated array. In addition, the publication of the array reference must be
1661 * safe according to the Java Memory Model requirements.
1662 * <p>
1663 * The safest approach to deal with an uninitialized array is to keep the reference to it in local
1664 * variable at least until the initialization is complete, and then publish it <b>once</b>, either
1665 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor,
1666 * or issuing a {@link #storeFence} before publishing the reference.
1667 * <p>
1668 * @implnote This method can only allocate primitive arrays, to avoid garbage reference
1669 * elements that could break heap integrity.
1670 *
1671 * @param componentType array component type to allocate
1672 * @param length array size to allocate
1673 * @throws IllegalArgumentException if component type is null, or not a primitive class;
1674 * or the length is negative
1675 */
1676 public Object allocateUninitializedArray(Class<?> componentType, int length) {
1677 if (componentType == null) {
1678 throw new IllegalArgumentException("Component type is null");
1679 }
1680 if (!componentType.isPrimitive()) {
1681 throw new IllegalArgumentException("Component type is not primitive");
1682 }
1683 if (length < 0) {
1684 throw new IllegalArgumentException("Negative length");
1685 }
1686 return allocateUninitializedArray0(componentType, length);
1687 }
1688
1689 @IntrinsicCandidate
1690 private Object allocateUninitializedArray0(Class<?> componentType, int length) {
1691 // These fallbacks provide zeroed arrays, but intrinsic is not required to
1692 // return the zeroed arrays.
1693 if (componentType == byte.class) return new byte[length];
1694 if (componentType == boolean.class) return new boolean[length];
1695 if (componentType == short.class) return new short[length];
1696 if (componentType == char.class) return new char[length];
1697 if (componentType == int.class) return new int[length];
1698 if (componentType == float.class) return new float[length];
1699 if (componentType == long.class) return new long[length];
1700 if (componentType == double.class) return new double[length];
1701 return null;
1702 }
1703
1704 /** Throws the exception without telling the verifier. */
1705 public native void throwException(Throwable ee);
1706
1707 /**
1708 * Atomically updates Java variable to {@code x} if it is currently
1709 * holding {@code expected}.
1710 *
1711 * <p>This operation has memory semantics of a {@code volatile} read
1712 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1713 *
1714 * @return {@code true} if successful
1715 */
1716 @IntrinsicCandidate
1717 public final native boolean compareAndSetReference(Object o, long offset,
1718 Object expected,
1719 Object x);
1720
1721 private final boolean isValueObject(Object o) {
1722 return o != null && o.getClass().isValue();
1723 }
1724
1725 /*
1726 * For value type, CAS should do substitutability test as opposed
1727 * to two pointers comparison.
1728 */
1729 @ForceInline
1730 public final <V> boolean compareAndSetReference(Object o, long offset,
1731 Class<?> type,
1732 V expected,
1733 V x) {
1734 if (isValueObject(expected)) {
1735 while (true) {
1736 Object witness = getReferenceVolatile(o, offset);
1737 if (witness != expected) {
1738 return false;
1739 }
1740 if (compareAndSetReference(o, offset, witness, x)) {
1741 return true;
1742 }
1743 }
1744 } else {
1745 return compareAndSetReference(o, offset, expected, x);
1746 }
1747 }
1748
1749 @ForceInline
1750 public final <V> boolean compareAndSetFlatValue(Object o, long offset,
1751 int layout,
1752 Class<?> valueType,
1753 V expected,
1754 V x) {
1755 Object[] array = newSpecialArray(valueType, 2, layout);
1756 return compareAndSetFlatValueAsBytes(array, o, offset, layout, valueType, expected, x);
1757 }
1758
1759 @IntrinsicCandidate
1760 public final native Object compareAndExchangeReference(Object o, long offset,
1761 Object expected,
1762 Object x);
1763
1764 @ForceInline
1765 public final <V> Object compareAndExchangeReference(Object o, long offset,
1766 Class<?> valueType,
1767 V expected,
1768 V x) {
1769 if (isValueObject(expected)) {
1770 while (true) {
1771 Object witness = getReferenceVolatile(o, offset);
1772 if (witness != expected) {
1773 return witness;
1774 }
1775 if (compareAndSetReference(o, offset, witness, x)) {
1776 return witness;
1777 }
1778 }
1779 } else {
1780 return compareAndExchangeReference(o, offset, expected, x);
1781 }
1782 }
1783
1784 @ForceInline
1785 public final <V> Object compareAndExchangeFlatValue(Object o, long offset,
1786 int layout,
1787 Class<?> valueType,
1788 V expected,
1789 V x) {
1790 Object[] array = newSpecialArray(valueType, 2, layout);
1791 compareAndSetFlatValueAsBytes(array, o, offset, layout, valueType, expected, x);
1792 return array[0];
1793 }
1794
1795 @IntrinsicCandidate
1796 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1797 Object expected,
1798 Object x) {
1799 return compareAndExchangeReference(o, offset, expected, x);
1800 }
1801
1802 public final <V> Object compareAndExchangeReferenceAcquire(Object o, long offset,
1803 Class<?> valueType,
1804 V expected,
1805 V x) {
1806 return compareAndExchangeReference(o, offset, valueType, expected, x);
1807 }
1808
1809 @ForceInline
1810 public final <V> Object compareAndExchangeFlatValueAcquire(Object o, long offset,
1811 int layout,
1812 Class<?> valueType,
1813 V expected,
1814 V x) {
1815 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1816 }
1817
1818 @IntrinsicCandidate
1819 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1820 Object expected,
1821 Object x) {
1822 return compareAndExchangeReference(o, offset, expected, x);
1823 }
1824
1825 public final <V> Object compareAndExchangeReferenceRelease(Object o, long offset,
1826 Class<?> valueType,
1827 V expected,
1828 V x) {
1829 return compareAndExchangeReference(o, offset, valueType, expected, x);
1830 }
1831
1832 @ForceInline
1833 public final <V> Object compareAndExchangeFlatValueRelease(Object o, long offset,
1834 int layout,
1835 Class<?> valueType,
1836 V expected,
1837 V x) {
1838 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1839 }
1840
1841 @IntrinsicCandidate
1842 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1843 Object expected,
1844 Object x) {
1845 return compareAndSetReference(o, offset, expected, x);
1846 }
1847
1848 public final <V> boolean weakCompareAndSetReferencePlain(Object o, long offset,
1849 Class<?> valueType,
1850 V expected,
1851 V x) {
1852 if (isValueObject(expected)) {
1853 return compareAndSetReference(o, offset, valueType, expected, x);
1854 } else {
1855 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1856 }
1857 }
1858
1859 @ForceInline
1860 public final <V> boolean weakCompareAndSetFlatValuePlain(Object o, long offset,
1861 int layout,
1862 Class<?> valueType,
1863 V expected,
1864 V x) {
1865 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1866 }
1867
1868 @IntrinsicCandidate
1869 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1870 Object expected,
1871 Object x) {
1872 return compareAndSetReference(o, offset, expected, x);
1873 }
1874
1875 public final <V> boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1876 Class<?> valueType,
1877 V expected,
1878 V x) {
1879 if (isValueObject(expected)) {
1880 return compareAndSetReference(o, offset, valueType, expected, x);
1881 } else {
1882 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1883 }
1884 }
1885
1886 @ForceInline
1887 public final <V> boolean weakCompareAndSetFlatValueAcquire(Object o, long offset,
1888 int layout,
1889 Class<?> valueType,
1890 V expected,
1891 V x) {
1892 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1893 }
1894
1895 @IntrinsicCandidate
1896 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1897 Object expected,
1898 Object x) {
1899 return compareAndSetReference(o, offset, expected, x);
1900 }
1901
1902 public final <V> boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1903 Class<?> valueType,
1904 V expected,
1905 V x) {
1906 if (isValueObject(expected)) {
1907 return compareAndSetReference(o, offset, valueType, expected, x);
1908 } else {
1909 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1910 }
1911 }
1912
1913 @ForceInline
1914 public final <V> boolean weakCompareAndSetFlatValueRelease(Object o, long offset,
1915 int layout,
1916 Class<?> valueType,
1917 V expected,
1918 V x) {
1919 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1920 }
1921
1922 @IntrinsicCandidate
1923 public final boolean weakCompareAndSetReference(Object o, long offset,
1924 Object expected,
1925 Object x) {
1926 return compareAndSetReference(o, offset, expected, x);
1927 }
1928
1929 public final <V> boolean weakCompareAndSetReference(Object o, long offset,
1930 Class<?> valueType,
1931 V expected,
1932 V x) {
1933 if (isValueObject(expected)) {
1934 return compareAndSetReference(o, offset, valueType, expected, x);
1935 } else {
1936 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1937 }
1938 }
1939
1940 @ForceInline
1941 public final <V> boolean weakCompareAndSetFlatValue(Object o, long offset,
1942 int layout,
1943 Class<?> valueType,
1944 V expected,
1945 V x) {
1946 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1947 }
1948
1949 /**
1950 * Atomically updates Java variable to {@code x} if it is currently
1951 * holding {@code expected}.
1952 *
1953 * <p>This operation has memory semantics of a {@code volatile} read
1954 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1955 *
1956 * @return {@code true} if successful
1957 */
1958 @IntrinsicCandidate
1959 public final native boolean compareAndSetInt(Object o, long offset,
1960 int expected,
1961 int x);
1962
1963 @IntrinsicCandidate
1964 public final native int compareAndExchangeInt(Object o, long offset,
1965 int expected,
1966 int x);
1967
1968 @IntrinsicCandidate
1969 public final int compareAndExchangeIntAcquire(Object o, long offset,
1970 int expected,
1971 int x) {
1972 return compareAndExchangeInt(o, offset, expected, x);
1973 }
1974
1975 @IntrinsicCandidate
1976 public final int compareAndExchangeIntRelease(Object o, long offset,
1977 int expected,
1978 int x) {
1979 return compareAndExchangeInt(o, offset, expected, x);
1980 }
1981
1982 @IntrinsicCandidate
1983 public final boolean weakCompareAndSetIntPlain(Object o, long offset,
1984 int expected,
1985 int x) {
1986 return compareAndSetInt(o, offset, expected, x);
1987 }
1988
1989 @IntrinsicCandidate
1990 public final boolean weakCompareAndSetIntAcquire(Object o, long offset,
1991 int expected,
1992 int x) {
1993 return compareAndSetInt(o, offset, expected, x);
1994 }
1995
1996 @IntrinsicCandidate
1997 public final boolean weakCompareAndSetIntRelease(Object o, long offset,
1998 int expected,
1999 int x) {
2000 return compareAndSetInt(o, offset, expected, x);
2001 }
2002
2003 @IntrinsicCandidate
2004 public final boolean weakCompareAndSetInt(Object o, long offset,
2005 int expected,
2006 int x) {
2007 return compareAndSetInt(o, offset, expected, x);
2008 }
2009
2010 @IntrinsicCandidate
2011 public final byte compareAndExchangeByte(Object o, long offset,
2012 byte expected,
2013 byte x) {
2014 long wordOffset = offset & ~3;
2015 int shift = (int) (offset & 3) << 3;
2016 if (BIG_ENDIAN) {
2017 shift = 24 - shift;
2018 }
2019 int mask = 0xFF << shift;
2020 int maskedExpected = (expected & 0xFF) << shift;
2021 int maskedX = (x & 0xFF) << shift;
2022 int fullWord;
2023 do {
2024 fullWord = getIntVolatile(o, wordOffset);
2025 if ((fullWord & mask) != maskedExpected)
2026 return (byte) ((fullWord & mask) >> shift);
2027 } while (!weakCompareAndSetInt(o, wordOffset,
2028 fullWord, (fullWord & ~mask) | maskedX));
2029 return expected;
2030 }
2031
2032 @IntrinsicCandidate
2033 public final boolean compareAndSetByte(Object o, long offset,
2034 byte expected,
2035 byte x) {
2036 return compareAndExchangeByte(o, offset, expected, x) == expected;
2037 }
2038
2039 @IntrinsicCandidate
2040 public final boolean weakCompareAndSetByte(Object o, long offset,
2041 byte expected,
2042 byte x) {
2043 return compareAndSetByte(o, offset, expected, x);
2044 }
2045
2046 @IntrinsicCandidate
2047 public final boolean weakCompareAndSetByteAcquire(Object o, long offset,
2048 byte expected,
2049 byte x) {
2050 return weakCompareAndSetByte(o, offset, expected, x);
2051 }
2052
2053 @IntrinsicCandidate
2054 public final boolean weakCompareAndSetByteRelease(Object o, long offset,
2055 byte expected,
2056 byte x) {
2057 return weakCompareAndSetByte(o, offset, expected, x);
2058 }
2059
2060 @IntrinsicCandidate
2061 public final boolean weakCompareAndSetBytePlain(Object o, long offset,
2062 byte expected,
2063 byte x) {
2064 return weakCompareAndSetByte(o, offset, expected, x);
2065 }
2066
2067 @IntrinsicCandidate
2068 public final byte compareAndExchangeByteAcquire(Object o, long offset,
2069 byte expected,
2070 byte x) {
2071 return compareAndExchangeByte(o, offset, expected, x);
2072 }
2073
2074 @IntrinsicCandidate
2075 public final byte compareAndExchangeByteRelease(Object o, long offset,
2076 byte expected,
2077 byte x) {
2078 return compareAndExchangeByte(o, offset, expected, x);
2079 }
2080
2081 @IntrinsicCandidate
2082 public final short compareAndExchangeShort(Object o, long offset,
2083 short expected,
2084 short x) {
2085 if ((offset & 3) == 3) {
2086 throw new IllegalArgumentException("Update spans the word, not supported");
2087 }
2088 long wordOffset = offset & ~3;
2089 int shift = (int) (offset & 3) << 3;
2090 if (BIG_ENDIAN) {
2091 shift = 16 - shift;
2092 }
2093 int mask = 0xFFFF << shift;
2094 int maskedExpected = (expected & 0xFFFF) << shift;
2095 int maskedX = (x & 0xFFFF) << shift;
2096 int fullWord;
2097 do {
2098 fullWord = getIntVolatile(o, wordOffset);
2099 if ((fullWord & mask) != maskedExpected) {
2100 return (short) ((fullWord & mask) >> shift);
2101 }
2102 } while (!weakCompareAndSetInt(o, wordOffset,
2103 fullWord, (fullWord & ~mask) | maskedX));
2104 return expected;
2105 }
2106
2107 @IntrinsicCandidate
2108 public final boolean compareAndSetShort(Object o, long offset,
2109 short expected,
2110 short x) {
2111 return compareAndExchangeShort(o, offset, expected, x) == expected;
2112 }
2113
2114 @IntrinsicCandidate
2115 public final boolean weakCompareAndSetShort(Object o, long offset,
2116 short expected,
2117 short x) {
2118 return compareAndSetShort(o, offset, expected, x);
2119 }
2120
2121 @IntrinsicCandidate
2122 public final boolean weakCompareAndSetShortAcquire(Object o, long offset,
2123 short expected,
2124 short x) {
2125 return weakCompareAndSetShort(o, offset, expected, x);
2126 }
2127
2128 @IntrinsicCandidate
2129 public final boolean weakCompareAndSetShortRelease(Object o, long offset,
2130 short expected,
2131 short x) {
2132 return weakCompareAndSetShort(o, offset, expected, x);
2133 }
2134
2135 @IntrinsicCandidate
2136 public final boolean weakCompareAndSetShortPlain(Object o, long offset,
2137 short expected,
2138 short x) {
2139 return weakCompareAndSetShort(o, offset, expected, x);
2140 }
2141
2142
2143 @IntrinsicCandidate
2144 public final short compareAndExchangeShortAcquire(Object o, long offset,
2145 short expected,
2146 short x) {
2147 return compareAndExchangeShort(o, offset, expected, x);
2148 }
2149
2150 @IntrinsicCandidate
2151 public final short compareAndExchangeShortRelease(Object o, long offset,
2152 short expected,
2153 short x) {
2154 return compareAndExchangeShort(o, offset, expected, x);
2155 }
2156
2157 @ForceInline
2158 private char s2c(short s) {
2159 return (char) s;
2160 }
2161
2162 @ForceInline
2163 private short c2s(char s) {
2164 return (short) s;
2165 }
2166
2167 @ForceInline
2168 public final boolean compareAndSetChar(Object o, long offset,
2169 char expected,
2170 char x) {
2171 return compareAndSetShort(o, offset, c2s(expected), c2s(x));
2172 }
2173
2174 @ForceInline
2175 public final char compareAndExchangeChar(Object o, long offset,
2176 char expected,
2177 char x) {
2178 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x)));
2179 }
2180
2181 @ForceInline
2182 public final char compareAndExchangeCharAcquire(Object o, long offset,
2183 char expected,
2184 char x) {
2185 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x)));
2186 }
2187
2188 @ForceInline
2189 public final char compareAndExchangeCharRelease(Object o, long offset,
2190 char expected,
2191 char x) {
2192 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x)));
2193 }
2194
2195 @ForceInline
2196 public final boolean weakCompareAndSetChar(Object o, long offset,
2197 char expected,
2198 char x) {
2199 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x));
2200 }
2201
2202 @ForceInline
2203 public final boolean weakCompareAndSetCharAcquire(Object o, long offset,
2204 char expected,
2205 char x) {
2206 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x));
2207 }
2208
2209 @ForceInline
2210 public final boolean weakCompareAndSetCharRelease(Object o, long offset,
2211 char expected,
2212 char x) {
2213 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x));
2214 }
2215
2216 @ForceInline
2217 public final boolean weakCompareAndSetCharPlain(Object o, long offset,
2218 char expected,
2219 char x) {
2220 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x));
2221 }
2222
2223 /**
2224 * The JVM converts integral values to boolean values using two
2225 * different conventions, byte testing against zero and truncation
2226 * to least-significant bit.
2227 *
2228 * <p>The JNI documents specify that, at least for returning
2229 * values from native methods, a Java boolean value is converted
2230 * to the value-set 0..1 by first truncating to a byte (0..255 or
2231 * maybe -128..127) and then testing against zero. Thus, Java
2232 * booleans in non-Java data structures are by convention
2233 * represented as 8-bit containers containing either zero (for
2234 * false) or any non-zero value (for true).
2235 *
2236 * <p>Java booleans in the heap are also stored in bytes, but are
2237 * strongly normalized to the value-set 0..1 (i.e., they are
2238 * truncated to the least-significant bit).
2239 *
2240 * <p>The main reason for having different conventions for
2241 * conversion is performance: Truncation to the least-significant
2242 * bit can be usually implemented with fewer (machine)
2243 * instructions than byte testing against zero.
2244 *
2245 * <p>A number of Unsafe methods load boolean values from the heap
2246 * as bytes. Unsafe converts those values according to the JNI
2247 * rules (i.e, using the "testing against zero" convention). The
2248 * method {@code byte2bool} implements that conversion.
2249 *
2250 * @param b the byte to be converted to boolean
2251 * @return the result of the conversion
2252 */
2253 @ForceInline
2254 private boolean byte2bool(byte b) {
2255 return b != 0;
2256 }
2257
2258 /**
2259 * Convert a boolean value to a byte. The return value is strongly
2260 * normalized to the value-set 0..1 (i.e., the value is truncated
2261 * to the least-significant bit). See {@link #byte2bool(byte)} for
2262 * more details on conversion conventions.
2263 *
2264 * @param b the boolean to be converted to byte (and then normalized)
2265 * @return the result of the conversion
2266 */
2267 @ForceInline
2268 private byte bool2byte(boolean b) {
2269 return b ? (byte)1 : (byte)0;
2270 }
2271
2272 @ForceInline
2273 public final boolean compareAndSetBoolean(Object o, long offset,
2274 boolean expected,
2275 boolean x) {
2276 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2277 }
2278
2279 @ForceInline
2280 public final boolean compareAndExchangeBoolean(Object o, long offset,
2281 boolean expected,
2282 boolean x) {
2283 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x)));
2284 }
2285
2286 @ForceInline
2287 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset,
2288 boolean expected,
2289 boolean x) {
2290 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x)));
2291 }
2292
2293 @ForceInline
2294 public final boolean compareAndExchangeBooleanRelease(Object o, long offset,
2295 boolean expected,
2296 boolean x) {
2297 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x)));
2298 }
2299
2300 @ForceInline
2301 public final boolean weakCompareAndSetBoolean(Object o, long offset,
2302 boolean expected,
2303 boolean x) {
2304 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x));
2305 }
2306
2307 @ForceInline
2308 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset,
2309 boolean expected,
2310 boolean x) {
2311 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x));
2312 }
2313
2314 @ForceInline
2315 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset,
2316 boolean expected,
2317 boolean x) {
2318 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x));
2319 }
2320
2321 @ForceInline
2322 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset,
2323 boolean expected,
2324 boolean x) {
2325 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x));
2326 }
2327
2328 /**
2329 * Atomically updates Java variable to {@code x} if it is currently
2330 * holding {@code expected}.
2331 *
2332 * <p>This operation has memory semantics of a {@code volatile} read
2333 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2334 *
2335 * @return {@code true} if successful
2336 */
2337 @ForceInline
2338 public final boolean compareAndSetFloat(Object o, long offset,
2339 float expected,
2340 float x) {
2341 return compareAndSetInt(o, offset,
2342 Float.floatToRawIntBits(expected),
2343 Float.floatToRawIntBits(x));
2344 }
2345
2346 @ForceInline
2347 public final float compareAndExchangeFloat(Object o, long offset,
2348 float expected,
2349 float x) {
2350 int w = compareAndExchangeInt(o, offset,
2351 Float.floatToRawIntBits(expected),
2352 Float.floatToRawIntBits(x));
2353 return Float.intBitsToFloat(w);
2354 }
2355
2356 @ForceInline
2357 public final float compareAndExchangeFloatAcquire(Object o, long offset,
2358 float expected,
2359 float x) {
2360 int w = compareAndExchangeIntAcquire(o, offset,
2361 Float.floatToRawIntBits(expected),
2362 Float.floatToRawIntBits(x));
2363 return Float.intBitsToFloat(w);
2364 }
2365
2366 @ForceInline
2367 public final float compareAndExchangeFloatRelease(Object o, long offset,
2368 float expected,
2369 float x) {
2370 int w = compareAndExchangeIntRelease(o, offset,
2371 Float.floatToRawIntBits(expected),
2372 Float.floatToRawIntBits(x));
2373 return Float.intBitsToFloat(w);
2374 }
2375
2376 @ForceInline
2377 public final boolean weakCompareAndSetFloatPlain(Object o, long offset,
2378 float expected,
2379 float x) {
2380 return weakCompareAndSetIntPlain(o, offset,
2381 Float.floatToRawIntBits(expected),
2382 Float.floatToRawIntBits(x));
2383 }
2384
2385 @ForceInline
2386 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset,
2387 float expected,
2388 float x) {
2389 return weakCompareAndSetIntAcquire(o, offset,
2390 Float.floatToRawIntBits(expected),
2391 Float.floatToRawIntBits(x));
2392 }
2393
2394 @ForceInline
2395 public final boolean weakCompareAndSetFloatRelease(Object o, long offset,
2396 float expected,
2397 float x) {
2398 return weakCompareAndSetIntRelease(o, offset,
2399 Float.floatToRawIntBits(expected),
2400 Float.floatToRawIntBits(x));
2401 }
2402
2403 @ForceInline
2404 public final boolean weakCompareAndSetFloat(Object o, long offset,
2405 float expected,
2406 float x) {
2407 return weakCompareAndSetInt(o, offset,
2408 Float.floatToRawIntBits(expected),
2409 Float.floatToRawIntBits(x));
2410 }
2411
2412 /**
2413 * Atomically updates Java variable to {@code x} if it is currently
2414 * holding {@code expected}.
2415 *
2416 * <p>This operation has memory semantics of a {@code volatile} read
2417 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2418 *
2419 * @return {@code true} if successful
2420 */
2421 @ForceInline
2422 public final boolean compareAndSetDouble(Object o, long offset,
2423 double expected,
2424 double x) {
2425 return compareAndSetLong(o, offset,
2426 Double.doubleToRawLongBits(expected),
2427 Double.doubleToRawLongBits(x));
2428 }
2429
2430 @ForceInline
2431 public final double compareAndExchangeDouble(Object o, long offset,
2432 double expected,
2433 double x) {
2434 long w = compareAndExchangeLong(o, offset,
2435 Double.doubleToRawLongBits(expected),
2436 Double.doubleToRawLongBits(x));
2437 return Double.longBitsToDouble(w);
2438 }
2439
2440 @ForceInline
2441 public final double compareAndExchangeDoubleAcquire(Object o, long offset,
2442 double expected,
2443 double x) {
2444 long w = compareAndExchangeLongAcquire(o, offset,
2445 Double.doubleToRawLongBits(expected),
2446 Double.doubleToRawLongBits(x));
2447 return Double.longBitsToDouble(w);
2448 }
2449
2450 @ForceInline
2451 public final double compareAndExchangeDoubleRelease(Object o, long offset,
2452 double expected,
2453 double x) {
2454 long w = compareAndExchangeLongRelease(o, offset,
2455 Double.doubleToRawLongBits(expected),
2456 Double.doubleToRawLongBits(x));
2457 return Double.longBitsToDouble(w);
2458 }
2459
2460 @ForceInline
2461 public final boolean weakCompareAndSetDoublePlain(Object o, long offset,
2462 double expected,
2463 double x) {
2464 return weakCompareAndSetLongPlain(o, offset,
2465 Double.doubleToRawLongBits(expected),
2466 Double.doubleToRawLongBits(x));
2467 }
2468
2469 @ForceInline
2470 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset,
2471 double expected,
2472 double x) {
2473 return weakCompareAndSetLongAcquire(o, offset,
2474 Double.doubleToRawLongBits(expected),
2475 Double.doubleToRawLongBits(x));
2476 }
2477
2478 @ForceInline
2479 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset,
2480 double expected,
2481 double x) {
2482 return weakCompareAndSetLongRelease(o, offset,
2483 Double.doubleToRawLongBits(expected),
2484 Double.doubleToRawLongBits(x));
2485 }
2486
2487 @ForceInline
2488 public final boolean weakCompareAndSetDouble(Object o, long offset,
2489 double expected,
2490 double x) {
2491 return weakCompareAndSetLong(o, offset,
2492 Double.doubleToRawLongBits(expected),
2493 Double.doubleToRawLongBits(x));
2494 }
2495
2496 /**
2497 * Atomically updates Java variable to {@code x} if it is currently
2498 * holding {@code expected}.
2499 *
2500 * <p>This operation has memory semantics of a {@code volatile} read
2501 * and write. Corresponds to C11 atomic_compare_exchange_strong.
2502 *
2503 * @return {@code true} if successful
2504 */
2505 @IntrinsicCandidate
2506 public final native boolean compareAndSetLong(Object o, long offset,
2507 long expected,
2508 long x);
2509
2510 @IntrinsicCandidate
2511 public final native long compareAndExchangeLong(Object o, long offset,
2512 long expected,
2513 long x);
2514
2515 @IntrinsicCandidate
2516 public final long compareAndExchangeLongAcquire(Object o, long offset,
2517 long expected,
2518 long x) {
2519 return compareAndExchangeLong(o, offset, expected, x);
2520 }
2521
2522 @IntrinsicCandidate
2523 public final long compareAndExchangeLongRelease(Object o, long offset,
2524 long expected,
2525 long x) {
2526 return compareAndExchangeLong(o, offset, expected, x);
2527 }
2528
2529 @IntrinsicCandidate
2530 public final boolean weakCompareAndSetLongPlain(Object o, long offset,
2531 long expected,
2532 long x) {
2533 return compareAndSetLong(o, offset, expected, x);
2534 }
2535
2536 @IntrinsicCandidate
2537 public final boolean weakCompareAndSetLongAcquire(Object o, long offset,
2538 long expected,
2539 long x) {
2540 return compareAndSetLong(o, offset, expected, x);
2541 }
2542
2543 @IntrinsicCandidate
2544 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2545 long expected,
2546 long x) {
2547 return compareAndSetLong(o, offset, expected, x);
2548 }
2549
2550 @IntrinsicCandidate
2551 public final boolean weakCompareAndSetLong(Object o, long offset,
2552 long expected,
2553 long x) {
2554 return compareAndSetLong(o, offset, expected, x);
2555 }
2556
2557 /**
2558 * Fetches a reference value from a given Java variable, with volatile
2559 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2560 */
2561 @IntrinsicCandidate
2562 public native Object getReferenceVolatile(Object o, long offset);
2563
2564 @ForceInline
2565 public final <V> Object getFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType) {
2566 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2567 Object res = getFlatValue(o, offset, layout, valueType);
2568 fullFence();
2569 return res;
2570 }
2571
2572 /**
2573 * Stores a reference value into a given Java variable, with
2574 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2575 */
2576 @IntrinsicCandidate
2577 public native void putReferenceVolatile(Object o, long offset, Object x);
2578
2579 @ForceInline
2580 public final <V> void putFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType, V x) {
2581 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2582 putFlatValueRelease(o, offset, layout, valueType, x);
2583 fullFence();
2584 }
2585
2586 /** Volatile version of {@link #getInt(Object, long)} */
2587 @IntrinsicCandidate
2588 public native int getIntVolatile(Object o, long offset);
2589
2590 /** Volatile version of {@link #putInt(Object, long, int)} */
2591 @IntrinsicCandidate
2592 public native void putIntVolatile(Object o, long offset, int x);
2593
2594 /** Volatile version of {@link #getBoolean(Object, long)} */
2595 @IntrinsicCandidate
2596 public native boolean getBooleanVolatile(Object o, long offset);
2597
2598 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2599 @IntrinsicCandidate
2600 public native void putBooleanVolatile(Object o, long offset, boolean x);
2601
2602 /** Volatile version of {@link #getByte(Object, long)} */
2603 @IntrinsicCandidate
2604 public native byte getByteVolatile(Object o, long offset);
2605
2606 /** Volatile version of {@link #putByte(Object, long, byte)} */
2607 @IntrinsicCandidate
2608 public native void putByteVolatile(Object o, long offset, byte x);
2609
2610 /** Volatile version of {@link #getShort(Object, long)} */
2611 @IntrinsicCandidate
2612 public native short getShortVolatile(Object o, long offset);
2613
2614 /** Volatile version of {@link #putShort(Object, long, short)} */
2615 @IntrinsicCandidate
2616 public native void putShortVolatile(Object o, long offset, short x);
2617
2618 /** Volatile version of {@link #getChar(Object, long)} */
2619 @IntrinsicCandidate
2620 public native char getCharVolatile(Object o, long offset);
2621
2622 /** Volatile version of {@link #putChar(Object, long, char)} */
2623 @IntrinsicCandidate
2624 public native void putCharVolatile(Object o, long offset, char x);
2625
2626 /** Volatile version of {@link #getLong(Object, long)} */
2627 @IntrinsicCandidate
2628 public native long getLongVolatile(Object o, long offset);
2629
2630 /** Volatile version of {@link #putLong(Object, long, long)} */
2631 @IntrinsicCandidate
2632 public native void putLongVolatile(Object o, long offset, long x);
2633
2634 /** Volatile version of {@link #getFloat(Object, long)} */
2635 @IntrinsicCandidate
2636 public native float getFloatVolatile(Object o, long offset);
2637
2638 /** Volatile version of {@link #putFloat(Object, long, float)} */
2639 @IntrinsicCandidate
2640 public native void putFloatVolatile(Object o, long offset, float x);
2641
2642 /** Volatile version of {@link #getDouble(Object, long)} */
2643 @IntrinsicCandidate
2644 public native double getDoubleVolatile(Object o, long offset);
2645
2646 /** Volatile version of {@link #putDouble(Object, long, double)} */
2647 @IntrinsicCandidate
2648 public native void putDoubleVolatile(Object o, long offset, double x);
2649
2650
2651
2652 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2653 @IntrinsicCandidate
2654 public final Object getReferenceAcquire(Object o, long offset) {
2655 return getReferenceVolatile(o, offset);
2656 }
2657
2658 @ForceInline
2659 public final <V> Object getFlatValueAcquire(Object o, long offset, int layout, Class<?> valueType) {
2660 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2661 Object res = getFlatValue(o, offset, layout, valueType);
2662 loadFence();
2663 return res;
2664 }
2665
2666 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2667 @IntrinsicCandidate
2668 public final boolean getBooleanAcquire(Object o, long offset) {
2669 return getBooleanVolatile(o, offset);
2670 }
2671
2672 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2673 @IntrinsicCandidate
2674 public final byte getByteAcquire(Object o, long offset) {
2675 return getByteVolatile(o, offset);
2676 }
2677
2678 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2679 @IntrinsicCandidate
2680 public final short getShortAcquire(Object o, long offset) {
2681 return getShortVolatile(o, offset);
2682 }
2683
2684 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2685 @IntrinsicCandidate
2686 public final char getCharAcquire(Object o, long offset) {
2687 return getCharVolatile(o, offset);
2688 }
2689
2690 /** Acquire version of {@link #getIntVolatile(Object, long)} */
2691 @IntrinsicCandidate
2692 public final int getIntAcquire(Object o, long offset) {
2693 return getIntVolatile(o, offset);
2694 }
2695
2696 /** Acquire version of {@link #getFloatVolatile(Object, long)} */
2697 @IntrinsicCandidate
2698 public final float getFloatAcquire(Object o, long offset) {
2699 return getFloatVolatile(o, offset);
2700 }
2701
2702 /** Acquire version of {@link #getLongVolatile(Object, long)} */
2703 @IntrinsicCandidate
2704 public final long getLongAcquire(Object o, long offset) {
2705 return getLongVolatile(o, offset);
2706 }
2707
2708 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */
2709 @IntrinsicCandidate
2710 public final double getDoubleAcquire(Object o, long offset) {
2711 return getDoubleVolatile(o, offset);
2712 }
2713
2714 /*
2715 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2716 * that do not guarantee immediate visibility of the store to
2717 * other threads. This method is generally only useful if the
2718 * underlying field is a Java volatile (or if an array cell, one
2719 * that is otherwise only accessed using volatile accesses).
2720 *
2721 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2722 */
2723
2724 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2725 @IntrinsicCandidate
2726 public final void putReferenceRelease(Object o, long offset, Object x) {
2727 putReferenceVolatile(o, offset, x);
2728 }
2729
2730 @ForceInline
2731 public final <V> void putFlatValueRelease(Object o, long offset, int layout, Class<?> valueType, V x) {
2732 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2733 storeFence();
2734 putFlatValue(o, offset, layout, valueType, x);
2735 }
2736
2737 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2738 @IntrinsicCandidate
2739 public final void putBooleanRelease(Object o, long offset, boolean x) {
2740 putBooleanVolatile(o, offset, x);
2741 }
2742
2743 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2744 @IntrinsicCandidate
2745 public final void putByteRelease(Object o, long offset, byte x) {
2746 putByteVolatile(o, offset, x);
2747 }
2748
2749 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2750 @IntrinsicCandidate
2751 public final void putShortRelease(Object o, long offset, short x) {
2752 putShortVolatile(o, offset, x);
2753 }
2754
2755 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2756 @IntrinsicCandidate
2757 public final void putCharRelease(Object o, long offset, char x) {
2758 putCharVolatile(o, offset, x);
2759 }
2760
2761 /** Release version of {@link #putIntVolatile(Object, long, int)} */
2762 @IntrinsicCandidate
2763 public final void putIntRelease(Object o, long offset, int x) {
2764 putIntVolatile(o, offset, x);
2765 }
2766
2767 /** Release version of {@link #putFloatVolatile(Object, long, float)} */
2768 @IntrinsicCandidate
2769 public final void putFloatRelease(Object o, long offset, float x) {
2770 putFloatVolatile(o, offset, x);
2771 }
2772
2773 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2774 @IntrinsicCandidate
2775 public final void putLongRelease(Object o, long offset, long x) {
2776 putLongVolatile(o, offset, x);
2777 }
2778
2779 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2780 @IntrinsicCandidate
2781 public final void putDoubleRelease(Object o, long offset, double x) {
2782 putDoubleVolatile(o, offset, x);
2783 }
2784
2785 // ------------------------------ Opaque --------------------------------------
2786
2787 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2788 @IntrinsicCandidate
2789 public final Object getReferenceOpaque(Object o, long offset) {
2790 return getReferenceVolatile(o, offset);
2791 }
2792
2793 @ForceInline
2794 public final <V> Object getFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType) {
2795 // this is stronger than opaque semantics
2796 return getFlatValueAcquire(o, offset, layout, valueType);
2797 }
2798
2799 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2800 @IntrinsicCandidate
2801 public final boolean getBooleanOpaque(Object o, long offset) {
2802 return getBooleanVolatile(o, offset);
2803 }
2804
2805 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2806 @IntrinsicCandidate
2807 public final byte getByteOpaque(Object o, long offset) {
2808 return getByteVolatile(o, offset);
2809 }
2810
2811 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2812 @IntrinsicCandidate
2813 public final short getShortOpaque(Object o, long offset) {
2814 return getShortVolatile(o, offset);
2815 }
2816
2817 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2818 @IntrinsicCandidate
2819 public final char getCharOpaque(Object o, long offset) {
2820 return getCharVolatile(o, offset);
2821 }
2822
2823 /** Opaque version of {@link #getIntVolatile(Object, long)} */
2824 @IntrinsicCandidate
2825 public final int getIntOpaque(Object o, long offset) {
2826 return getIntVolatile(o, offset);
2827 }
2828
2829 /** Opaque version of {@link #getFloatVolatile(Object, long)} */
2830 @IntrinsicCandidate
2831 public final float getFloatOpaque(Object o, long offset) {
2832 return getFloatVolatile(o, offset);
2833 }
2834
2835 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2836 @IntrinsicCandidate
2837 public final long getLongOpaque(Object o, long offset) {
2838 return getLongVolatile(o, offset);
2839 }
2840
2841 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2842 @IntrinsicCandidate
2843 public final double getDoubleOpaque(Object o, long offset) {
2844 return getDoubleVolatile(o, offset);
2845 }
2846
2847 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2848 @IntrinsicCandidate
2849 public final void putReferenceOpaque(Object o, long offset, Object x) {
2850 putReferenceVolatile(o, offset, x);
2851 }
2852
2853 @ForceInline
2854 public final <V> void putFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType, V x) {
2855 // this is stronger than opaque semantics
2856 putFlatValueRelease(o, offset, layout, valueType, x);
2857 }
2858
2859 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2860 @IntrinsicCandidate
2861 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2862 putBooleanVolatile(o, offset, x);
2863 }
2864
2865 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2866 @IntrinsicCandidate
2867 public final void putByteOpaque(Object o, long offset, byte x) {
2868 putByteVolatile(o, offset, x);
2869 }
2870
2871 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2872 @IntrinsicCandidate
2873 public final void putShortOpaque(Object o, long offset, short x) {
2874 putShortVolatile(o, offset, x);
2875 }
2876
2877 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2878 @IntrinsicCandidate
2879 public final void putCharOpaque(Object o, long offset, char x) {
2880 putCharVolatile(o, offset, x);
2881 }
2882
2883 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */
2884 @IntrinsicCandidate
2885 public final void putIntOpaque(Object o, long offset, int x) {
2886 putIntVolatile(o, offset, x);
2887 }
2888
2889 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2890 @IntrinsicCandidate
2891 public final void putFloatOpaque(Object o, long offset, float x) {
2892 putFloatVolatile(o, offset, x);
2893 }
2894
2895 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2896 @IntrinsicCandidate
2897 public final void putLongOpaque(Object o, long offset, long x) {
2898 putLongVolatile(o, offset, x);
2899 }
2900
2901 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2902 @IntrinsicCandidate
2903 public final void putDoubleOpaque(Object o, long offset, double x) {
2904 putDoubleVolatile(o, offset, x);
2905 }
2906
2907 @ForceInline
2908 private boolean compareAndSetFlatValueAsBytes(Object[] array, Object o, long offset, int layout, Class<?> valueType, Object expected, Object x) {
2909 // We can convert between a value object and a binary value (of suitable size) using array elements.
2910 // This only works if the payload contains no oops (see VarHandles::isAtomicFlat).
2911 // Thus, we can implement the CAS with a plain numeric CAS.
2912
2913 // array[0]: witness (put as binary, get as object), at base
2914 // array[1]: x (put as object, get as binary), at base + scale
2915 // When witness == expected, the witness binary may be different from the expected binary.
2916 // This happens when compiler does not zero unused positions in the witness.
2917 // So we must obtain the witness binary and use it as expected binary for the numeric CAS.
2918 long base = arrayInstanceBaseOffset(array);
2919 int scale = arrayInstanceIndexScale(array);
2920 putFlatValue(array, base + scale, layout, valueType, x); // put x as object
2921 switch (scale) {
2922 case 1: {
2923 do {
2924 byte witnessByte = getByteVolatile(o, offset);
2925 putByte(array, base, witnessByte); // put witness as binary
2926 Object witness = getFlatValue(array, base, layout, valueType); // get witness as object
2927 if (witness != expected) {
2928 return false;
2929 }
2930 byte xByte = getByte(array, base + scale); // get x as binary
2931 if (compareAndSetByte(o, offset, witnessByte, xByte)) {
2932 return true;
2933 }
2934 } while (true);
2935 }
2936 case 2: {
2937 do {
2938 short witnessShort = getShortVolatile(o, offset);
2939 putShort(array, base, witnessShort); // put witness as binary
2940 Object witness = getFlatValue(array, base, layout, valueType); // get witness as object
2941 if (witness != expected) {
2942 return false;
2943 }
2944 short xShort = getShort(array, base + scale); // get x as binary
2945 if (compareAndSetShort(o, offset, witnessShort, xShort)) {
2946 return true;
2947 }
2948 } while (true);
2949 }
2950 case 4: {
2951 do {
2952 int witnessInt = getIntVolatile(o, offset);
2953 putInt(array, base, witnessInt); // put witness as binary
2954 Object witness = getFlatValue(array, base, layout, valueType); // get witness as object
2955 if (witness != expected) {
2956 return false;
2957 }
2958 int xInt = getInt(array, base + scale); // get x as binary
2959 if (compareAndSetInt(o, offset, witnessInt, xInt)) {
2960 return true;
2961 }
2962 } while (true);
2963 }
2964 case 8: {
2965 do {
2966 long witnessLong = getLongVolatile(o, offset);
2967 putLong(array, base, witnessLong); // put witness as binary
2968 Object witness = getFlatValue(array, base, layout, valueType);
2969 if (witness != expected) {
2970 return false;
2971 }
2972 long xLong = getLong(array, base + scale); // get x as binary
2973 if (compareAndSetLong(o, offset, witnessLong, xLong)) {
2974 return true;
2975 }
2976 } while (true);
2977 }
2978 default: {
2979 throw new UnsupportedOperationException();
2980 }
2981 }
2982 }
2983
2984 /**
2985 * Unblocks the given thread blocked on {@code park}, or, if it is
2986 * not blocked, causes the subsequent call to {@code park} not to
2987 * block. Note: this operation is "unsafe" solely because the
2988 * caller must somehow ensure that the thread has not been
2989 * destroyed. Nothing special is usually required to ensure this
2990 * when called from Java (in which there will ordinarily be a live
2991 * reference to the thread) but this is not nearly-automatically
2992 * so when calling from native code.
2993 *
2994 * @param thread the thread to unpark.
2995 */
2996 @IntrinsicCandidate
2997 public native void unpark(Object thread);
2998
2999 /**
3000 * Blocks current thread, returning when a balancing
3001 * {@code unpark} occurs, or a balancing {@code unpark} has
3002 * already occurred, or the thread is interrupted, or, if not
3003 * absolute and time is not zero, the given time nanoseconds have
3004 * elapsed, or if absolute, the given deadline in milliseconds
3005 * since Epoch has passed, or spuriously (i.e., returning for no
3006 * "reason"). Note: This operation is in the Unsafe class only
3007 * because {@code unpark} is, so it would be strange to place it
3008 * elsewhere.
3009 */
3010 @IntrinsicCandidate
3011 public native void park(boolean isAbsolute, long time);
3012
3013 /**
3014 * Gets the load average in the system run queue assigned
3015 * to the available processors averaged over various periods of time.
3016 * This method retrieves the given {@code nelem} samples and
3017 * assigns to the elements of the given {@code loadavg} array.
3018 * The system imposes a maximum of 3 samples, representing
3019 * averages over the last 1, 5, and 15 minutes, respectively.
3020 *
3021 * @param loadavg an array of double of size nelems
3022 * @param nelems the number of samples to be retrieved and
3023 * must be 1 to 3.
3024 *
3025 * @return the number of samples actually retrieved; or -1
3026 * if the load average is unobtainable.
3027 */
3028 public int getLoadAverage(double[] loadavg, int nelems) {
3029 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) {
3030 throw new ArrayIndexOutOfBoundsException();
3031 }
3032
3033 return getLoadAverage0(loadavg, nelems);
3034 }
3035
3036 // The following contain CAS-based Java implementations used on
3037 // platforms not supporting native instructions
3038
3039 /**
3040 * Atomically adds the given value to the current value of a field
3041 * or array element within the given object {@code o}
3042 * at the given {@code offset}.
3043 *
3044 * @param o object/array to update the field/element in
3045 * @param offset field/element offset
3046 * @param delta the value to add
3047 * @return the previous value
3048 * @since 1.8
3049 */
3050 @IntrinsicCandidate
3051 public final int getAndAddInt(Object o, long offset, int delta) {
3052 int v;
3053 do {
3054 v = getIntVolatile(o, offset);
3055 } while (!weakCompareAndSetInt(o, offset, v, v + delta));
3056 return v;
3057 }
3058
3059 @ForceInline
3060 public final int getAndAddIntRelease(Object o, long offset, int delta) {
3061 int v;
3062 do {
3063 v = getInt(o, offset);
3064 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta));
3065 return v;
3066 }
3067
3068 @ForceInline
3069 public final int getAndAddIntAcquire(Object o, long offset, int delta) {
3070 int v;
3071 do {
3072 v = getIntAcquire(o, offset);
3073 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta));
3074 return v;
3075 }
3076
3077 /**
3078 * Atomically adds the given value to the current value of a field
3079 * or array element within the given object {@code o}
3080 * at the given {@code offset}.
3081 *
3082 * @param o object/array to update the field/element in
3083 * @param offset field/element offset
3084 * @param delta the value to add
3085 * @return the previous value
3086 * @since 1.8
3087 */
3088 @IntrinsicCandidate
3089 public final long getAndAddLong(Object o, long offset, long delta) {
3090 long v;
3091 do {
3092 v = getLongVolatile(o, offset);
3093 } while (!weakCompareAndSetLong(o, offset, v, v + delta));
3094 return v;
3095 }
3096
3097 @ForceInline
3098 public final long getAndAddLongRelease(Object o, long offset, long delta) {
3099 long v;
3100 do {
3101 v = getLong(o, offset);
3102 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta));
3103 return v;
3104 }
3105
3106 @ForceInline
3107 public final long getAndAddLongAcquire(Object o, long offset, long delta) {
3108 long v;
3109 do {
3110 v = getLongAcquire(o, offset);
3111 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta));
3112 return v;
3113 }
3114
3115 @IntrinsicCandidate
3116 public final byte getAndAddByte(Object o, long offset, byte delta) {
3117 byte v;
3118 do {
3119 v = getByteVolatile(o, offset);
3120 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta)));
3121 return v;
3122 }
3123
3124 @ForceInline
3125 public final byte getAndAddByteRelease(Object o, long offset, byte delta) {
3126 byte v;
3127 do {
3128 v = getByte(o, offset);
3129 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta)));
3130 return v;
3131 }
3132
3133 @ForceInline
3134 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) {
3135 byte v;
3136 do {
3137 v = getByteAcquire(o, offset);
3138 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta)));
3139 return v;
3140 }
3141
3142 @IntrinsicCandidate
3143 public final short getAndAddShort(Object o, long offset, short delta) {
3144 short v;
3145 do {
3146 v = getShortVolatile(o, offset);
3147 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta)));
3148 return v;
3149 }
3150
3151 @ForceInline
3152 public final short getAndAddShortRelease(Object o, long offset, short delta) {
3153 short v;
3154 do {
3155 v = getShort(o, offset);
3156 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta)));
3157 return v;
3158 }
3159
3160 @ForceInline
3161 public final short getAndAddShortAcquire(Object o, long offset, short delta) {
3162 short v;
3163 do {
3164 v = getShortAcquire(o, offset);
3165 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta)));
3166 return v;
3167 }
3168
3169 @ForceInline
3170 public final char getAndAddChar(Object o, long offset, char delta) {
3171 return (char) getAndAddShort(o, offset, (short) delta);
3172 }
3173
3174 @ForceInline
3175 public final char getAndAddCharRelease(Object o, long offset, char delta) {
3176 return (char) getAndAddShortRelease(o, offset, (short) delta);
3177 }
3178
3179 @ForceInline
3180 public final char getAndAddCharAcquire(Object o, long offset, char delta) {
3181 return (char) getAndAddShortAcquire(o, offset, (short) delta);
3182 }
3183
3184 @ForceInline
3185 public final float getAndAddFloat(Object o, long offset, float delta) {
3186 int expectedBits;
3187 float v;
3188 do {
3189 // Load and CAS with the raw bits to avoid issues with NaNs and
3190 // possible bit conversion from signaling NaNs to quiet NaNs that
3191 // may result in the loop not terminating.
3192 expectedBits = getIntVolatile(o, offset);
3193 v = Float.intBitsToFloat(expectedBits);
3194 } while (!weakCompareAndSetInt(o, offset,
3195 expectedBits, Float.floatToRawIntBits(v + delta)));
3196 return v;
3197 }
3198
3199 @ForceInline
3200 public final float getAndAddFloatRelease(Object o, long offset, float delta) {
3201 int expectedBits;
3202 float v;
3203 do {
3204 // Load and CAS with the raw bits to avoid issues with NaNs and
3205 // possible bit conversion from signaling NaNs to quiet NaNs that
3206 // may result in the loop not terminating.
3207 expectedBits = getInt(o, offset);
3208 v = Float.intBitsToFloat(expectedBits);
3209 } while (!weakCompareAndSetIntRelease(o, offset,
3210 expectedBits, Float.floatToRawIntBits(v + delta)));
3211 return v;
3212 }
3213
3214 @ForceInline
3215 public final float getAndAddFloatAcquire(Object o, long offset, float delta) {
3216 int expectedBits;
3217 float v;
3218 do {
3219 // Load and CAS with the raw bits to avoid issues with NaNs and
3220 // possible bit conversion from signaling NaNs to quiet NaNs that
3221 // may result in the loop not terminating.
3222 expectedBits = getIntAcquire(o, offset);
3223 v = Float.intBitsToFloat(expectedBits);
3224 } while (!weakCompareAndSetIntAcquire(o, offset,
3225 expectedBits, Float.floatToRawIntBits(v + delta)));
3226 return v;
3227 }
3228
3229 @ForceInline
3230 public final double getAndAddDouble(Object o, long offset, double delta) {
3231 long expectedBits;
3232 double v;
3233 do {
3234 // Load and CAS with the raw bits to avoid issues with NaNs and
3235 // possible bit conversion from signaling NaNs to quiet NaNs that
3236 // may result in the loop not terminating.
3237 expectedBits = getLongVolatile(o, offset);
3238 v = Double.longBitsToDouble(expectedBits);
3239 } while (!weakCompareAndSetLong(o, offset,
3240 expectedBits, Double.doubleToRawLongBits(v + delta)));
3241 return v;
3242 }
3243
3244 @ForceInline
3245 public final double getAndAddDoubleRelease(Object o, long offset, double delta) {
3246 long expectedBits;
3247 double v;
3248 do {
3249 // Load and CAS with the raw bits to avoid issues with NaNs and
3250 // possible bit conversion from signaling NaNs to quiet NaNs that
3251 // may result in the loop not terminating.
3252 expectedBits = getLong(o, offset);
3253 v = Double.longBitsToDouble(expectedBits);
3254 } while (!weakCompareAndSetLongRelease(o, offset,
3255 expectedBits, Double.doubleToRawLongBits(v + delta)));
3256 return v;
3257 }
3258
3259 @ForceInline
3260 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) {
3261 long expectedBits;
3262 double v;
3263 do {
3264 // Load and CAS with the raw bits to avoid issues with NaNs and
3265 // possible bit conversion from signaling NaNs to quiet NaNs that
3266 // may result in the loop not terminating.
3267 expectedBits = getLongAcquire(o, offset);
3268 v = Double.longBitsToDouble(expectedBits);
3269 } while (!weakCompareAndSetLongAcquire(o, offset,
3270 expectedBits, Double.doubleToRawLongBits(v + delta)));
3271 return v;
3272 }
3273
3274 /**
3275 * Atomically exchanges the given value with the current value of
3276 * a field or array element within the given object {@code o}
3277 * at the given {@code offset}.
3278 *
3279 * @param o object/array to update the field/element in
3280 * @param offset field/element offset
3281 * @param newValue new value
3282 * @return the previous value
3283 * @since 1.8
3284 */
3285 @IntrinsicCandidate
3286 public final int getAndSetInt(Object o, long offset, int newValue) {
3287 int v;
3288 do {
3289 v = getIntVolatile(o, offset);
3290 } while (!weakCompareAndSetInt(o, offset, v, newValue));
3291 return v;
3292 }
3293
3294 @ForceInline
3295 public final int getAndSetIntRelease(Object o, long offset, int newValue) {
3296 int v;
3297 do {
3298 v = getInt(o, offset);
3299 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue));
3300 return v;
3301 }
3302
3303 @ForceInline
3304 public final int getAndSetIntAcquire(Object o, long offset, int newValue) {
3305 int v;
3306 do {
3307 v = getIntAcquire(o, offset);
3308 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue));
3309 return v;
3310 }
3311
3312 /**
3313 * Atomically exchanges the given value with the current value of
3314 * a field or array element within the given object {@code o}
3315 * at the given {@code offset}.
3316 *
3317 * @param o object/array to update the field/element in
3318 * @param offset field/element offset
3319 * @param newValue new value
3320 * @return the previous value
3321 * @since 1.8
3322 */
3323 @IntrinsicCandidate
3324 public final long getAndSetLong(Object o, long offset, long newValue) {
3325 long v;
3326 do {
3327 v = getLongVolatile(o, offset);
3328 } while (!weakCompareAndSetLong(o, offset, v, newValue));
3329 return v;
3330 }
3331
3332 @ForceInline
3333 public final long getAndSetLongRelease(Object o, long offset, long newValue) {
3334 long v;
3335 do {
3336 v = getLong(o, offset);
3337 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue));
3338 return v;
3339 }
3340
3341 @ForceInline
3342 public final long getAndSetLongAcquire(Object o, long offset, long newValue) {
3343 long v;
3344 do {
3345 v = getLongAcquire(o, offset);
3346 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue));
3347 return v;
3348 }
3349
3350 /**
3351 * Atomically exchanges the given reference value with the current
3352 * reference value of a field or array element within the given
3353 * object {@code o} at the given {@code offset}.
3354 *
3355 * @param o object/array to update the field/element in
3356 * @param offset field/element offset
3357 * @param newValue new value
3358 * @return the previous value
3359 * @since 1.8
3360 */
3361 @IntrinsicCandidate
3362 public final Object getAndSetReference(Object o, long offset, Object newValue) {
3363 Object v;
3364 do {
3365 v = getReferenceVolatile(o, offset);
3366 } while (!weakCompareAndSetReference(o, offset, v, newValue));
3367 return v;
3368 }
3369
3370 @ForceInline
3371 public final Object getAndSetReference(Object o, long offset, Class<?> valueType, Object newValue) {
3372 Object v;
3373 do {
3374 v = getReferenceVolatile(o, offset);
3375 } while (!compareAndSetReference(o, offset, valueType, v, newValue));
3376 return v;
3377 }
3378
3379 @ForceInline
3380 public Object getAndSetFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, Object newValue) {
3381 Object v;
3382 do {
3383 v = getFlatValueVolatile(o, offset, layoutKind, valueType);
3384 } while (!compareAndSetFlatValue(o, offset, layoutKind, valueType, v, newValue));
3385 return v;
3386 }
3387
3388 @ForceInline
3389 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
3390 Object v;
3391 do {
3392 v = getReference(o, offset);
3393 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
3394 return v;
3395 }
3396
3397 @ForceInline
3398 public final Object getAndSetReferenceRelease(Object o, long offset, Class<?> valueType, Object newValue) {
3399 return getAndSetReference(o, offset, valueType, newValue);
3400 }
3401
3402 @ForceInline
3403 public Object getAndSetFlatValueRelease(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3404 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3405 }
3406
3407 @ForceInline
3408 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
3409 Object v;
3410 do {
3411 v = getReferenceAcquire(o, offset);
3412 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
3413 return v;
3414 }
3415
3416 @ForceInline
3417 public final Object getAndSetReferenceAcquire(Object o, long offset, Class<?> valueType, Object newValue) {
3418 return getAndSetReference(o, offset, valueType, newValue);
3419 }
3420
3421 @ForceInline
3422 public Object getAndSetFlatValueAcquire(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3423 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3424 }
3425
3426 @IntrinsicCandidate
3427 public final byte getAndSetByte(Object o, long offset, byte newValue) {
3428 byte v;
3429 do {
3430 v = getByteVolatile(o, offset);
3431 } while (!weakCompareAndSetByte(o, offset, v, newValue));
3432 return v;
3433 }
3434
3435 @ForceInline
3436 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
3437 byte v;
3438 do {
3439 v = getByte(o, offset);
3440 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
3441 return v;
3442 }
3443
3444 @ForceInline
3445 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
3446 byte v;
3447 do {
3448 v = getByteAcquire(o, offset);
3449 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue));
3450 return v;
3451 }
3452
3453 @ForceInline
3454 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) {
3455 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue)));
3456 }
3457
3458 @ForceInline
3459 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) {
3460 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue)));
3461 }
3462
3463 @ForceInline
3464 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) {
3465 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue)));
3466 }
3467
3468 @IntrinsicCandidate
3469 public final short getAndSetShort(Object o, long offset, short newValue) {
3470 short v;
3471 do {
3472 v = getShortVolatile(o, offset);
3473 } while (!weakCompareAndSetShort(o, offset, v, newValue));
3474 return v;
3475 }
3476
3477 @ForceInline
3478 public final short getAndSetShortRelease(Object o, long offset, short newValue) {
3479 short v;
3480 do {
3481 v = getShort(o, offset);
3482 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue));
3483 return v;
3484 }
3485
3486 @ForceInline
3487 public final short getAndSetShortAcquire(Object o, long offset, short newValue) {
3488 short v;
3489 do {
3490 v = getShortAcquire(o, offset);
3491 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue));
3492 return v;
3493 }
3494
3495 @ForceInline
3496 public final char getAndSetChar(Object o, long offset, char newValue) {
3497 return s2c(getAndSetShort(o, offset, c2s(newValue)));
3498 }
3499
3500 @ForceInline
3501 public final char getAndSetCharRelease(Object o, long offset, char newValue) {
3502 return s2c(getAndSetShortRelease(o, offset, c2s(newValue)));
3503 }
3504
3505 @ForceInline
3506 public final char getAndSetCharAcquire(Object o, long offset, char newValue) {
3507 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue)));
3508 }
3509
3510 @ForceInline
3511 public final float getAndSetFloat(Object o, long offset, float newValue) {
3512 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue));
3513 return Float.intBitsToFloat(v);
3514 }
3515
3516 @ForceInline
3517 public final float getAndSetFloatRelease(Object o, long offset, float newValue) {
3518 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue));
3519 return Float.intBitsToFloat(v);
3520 }
3521
3522 @ForceInline
3523 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) {
3524 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue));
3525 return Float.intBitsToFloat(v);
3526 }
3527
3528 @ForceInline
3529 public final double getAndSetDouble(Object o, long offset, double newValue) {
3530 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue));
3531 return Double.longBitsToDouble(v);
3532 }
3533
3534 @ForceInline
3535 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) {
3536 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue));
3537 return Double.longBitsToDouble(v);
3538 }
3539
3540 @ForceInline
3541 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) {
3542 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue));
3543 return Double.longBitsToDouble(v);
3544 }
3545
3546
3547 // The following contain CAS-based Java implementations used on
3548 // platforms not supporting native instructions
3549
3550 @ForceInline
3551 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) {
3552 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask)));
3553 }
3554
3555 @ForceInline
3556 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) {
3557 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask)));
3558 }
3559
3560 @ForceInline
3561 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) {
3562 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask)));
3563 }
3564
3565 @ForceInline
3566 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) {
3567 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask)));
3568 }
3569
3570 @ForceInline
3571 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) {
3572 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask)));
3573 }
3574
3575 @ForceInline
3576 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) {
3577 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask)));
3578 }
3579
3580 @ForceInline
3581 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) {
3582 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask)));
3583 }
3584
3585 @ForceInline
3586 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) {
3587 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask)));
3588 }
3589
3590 @ForceInline
3591 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) {
3592 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask)));
3593 }
3594
3595
3596 @ForceInline
3597 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) {
3598 byte current;
3599 do {
3600 current = getByteVolatile(o, offset);
3601 } while (!weakCompareAndSetByte(o, offset,
3602 current, (byte) (current | mask)));
3603 return current;
3604 }
3605
3606 @ForceInline
3607 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) {
3608 byte current;
3609 do {
3610 current = getByte(o, offset);
3611 } while (!weakCompareAndSetByteRelease(o, offset,
3612 current, (byte) (current | mask)));
3613 return current;
3614 }
3615
3616 @ForceInline
3617 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) {
3618 byte current;
3619 do {
3620 // Plain read, the value is a hint, the acquire CAS does the work
3621 current = getByte(o, offset);
3622 } while (!weakCompareAndSetByteAcquire(o, offset,
3623 current, (byte) (current | mask)));
3624 return current;
3625 }
3626
3627 @ForceInline
3628 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) {
3629 byte current;
3630 do {
3631 current = getByteVolatile(o, offset);
3632 } while (!weakCompareAndSetByte(o, offset,
3633 current, (byte) (current & mask)));
3634 return current;
3635 }
3636
3637 @ForceInline
3638 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) {
3639 byte current;
3640 do {
3641 current = getByte(o, offset);
3642 } while (!weakCompareAndSetByteRelease(o, offset,
3643 current, (byte) (current & mask)));
3644 return current;
3645 }
3646
3647 @ForceInline
3648 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) {
3649 byte current;
3650 do {
3651 // Plain read, the value is a hint, the acquire CAS does the work
3652 current = getByte(o, offset);
3653 } while (!weakCompareAndSetByteAcquire(o, offset,
3654 current, (byte) (current & mask)));
3655 return current;
3656 }
3657
3658 @ForceInline
3659 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) {
3660 byte current;
3661 do {
3662 current = getByteVolatile(o, offset);
3663 } while (!weakCompareAndSetByte(o, offset,
3664 current, (byte) (current ^ mask)));
3665 return current;
3666 }
3667
3668 @ForceInline
3669 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) {
3670 byte current;
3671 do {
3672 current = getByte(o, offset);
3673 } while (!weakCompareAndSetByteRelease(o, offset,
3674 current, (byte) (current ^ mask)));
3675 return current;
3676 }
3677
3678 @ForceInline
3679 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) {
3680 byte current;
3681 do {
3682 // Plain read, the value is a hint, the acquire CAS does the work
3683 current = getByte(o, offset);
3684 } while (!weakCompareAndSetByteAcquire(o, offset,
3685 current, (byte) (current ^ mask)));
3686 return current;
3687 }
3688
3689
3690 @ForceInline
3691 public final char getAndBitwiseOrChar(Object o, long offset, char mask) {
3692 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask)));
3693 }
3694
3695 @ForceInline
3696 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) {
3697 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask)));
3698 }
3699
3700 @ForceInline
3701 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) {
3702 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask)));
3703 }
3704
3705 @ForceInline
3706 public final char getAndBitwiseAndChar(Object o, long offset, char mask) {
3707 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask)));
3708 }
3709
3710 @ForceInline
3711 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) {
3712 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask)));
3713 }
3714
3715 @ForceInline
3716 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) {
3717 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask)));
3718 }
3719
3720 @ForceInline
3721 public final char getAndBitwiseXorChar(Object o, long offset, char mask) {
3722 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask)));
3723 }
3724
3725 @ForceInline
3726 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) {
3727 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask)));
3728 }
3729
3730 @ForceInline
3731 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) {
3732 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask)));
3733 }
3734
3735
3736 @ForceInline
3737 public final short getAndBitwiseOrShort(Object o, long offset, short mask) {
3738 short current;
3739 do {
3740 current = getShortVolatile(o, offset);
3741 } while (!weakCompareAndSetShort(o, offset,
3742 current, (short) (current | mask)));
3743 return current;
3744 }
3745
3746 @ForceInline
3747 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) {
3748 short current;
3749 do {
3750 current = getShort(o, offset);
3751 } while (!weakCompareAndSetShortRelease(o, offset,
3752 current, (short) (current | mask)));
3753 return current;
3754 }
3755
3756 @ForceInline
3757 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) {
3758 short current;
3759 do {
3760 // Plain read, the value is a hint, the acquire CAS does the work
3761 current = getShort(o, offset);
3762 } while (!weakCompareAndSetShortAcquire(o, offset,
3763 current, (short) (current | mask)));
3764 return current;
3765 }
3766
3767 @ForceInline
3768 public final short getAndBitwiseAndShort(Object o, long offset, short mask) {
3769 short current;
3770 do {
3771 current = getShortVolatile(o, offset);
3772 } while (!weakCompareAndSetShort(o, offset,
3773 current, (short) (current & mask)));
3774 return current;
3775 }
3776
3777 @ForceInline
3778 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) {
3779 short current;
3780 do {
3781 current = getShort(o, offset);
3782 } while (!weakCompareAndSetShortRelease(o, offset,
3783 current, (short) (current & mask)));
3784 return current;
3785 }
3786
3787 @ForceInline
3788 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) {
3789 short current;
3790 do {
3791 // Plain read, the value is a hint, the acquire CAS does the work
3792 current = getShort(o, offset);
3793 } while (!weakCompareAndSetShortAcquire(o, offset,
3794 current, (short) (current & mask)));
3795 return current;
3796 }
3797
3798 @ForceInline
3799 public final short getAndBitwiseXorShort(Object o, long offset, short mask) {
3800 short current;
3801 do {
3802 current = getShortVolatile(o, offset);
3803 } while (!weakCompareAndSetShort(o, offset,
3804 current, (short) (current ^ mask)));
3805 return current;
3806 }
3807
3808 @ForceInline
3809 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) {
3810 short current;
3811 do {
3812 current = getShort(o, offset);
3813 } while (!weakCompareAndSetShortRelease(o, offset,
3814 current, (short) (current ^ mask)));
3815 return current;
3816 }
3817
3818 @ForceInline
3819 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) {
3820 short current;
3821 do {
3822 // Plain read, the value is a hint, the acquire CAS does the work
3823 current = getShort(o, offset);
3824 } while (!weakCompareAndSetShortAcquire(o, offset,
3825 current, (short) (current ^ mask)));
3826 return current;
3827 }
3828
3829
3830 @ForceInline
3831 public final int getAndBitwiseOrInt(Object o, long offset, int mask) {
3832 int current;
3833 do {
3834 current = getIntVolatile(o, offset);
3835 } while (!weakCompareAndSetInt(o, offset,
3836 current, current | mask));
3837 return current;
3838 }
3839
3840 @ForceInline
3841 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) {
3842 int current;
3843 do {
3844 current = getInt(o, offset);
3845 } while (!weakCompareAndSetIntRelease(o, offset,
3846 current, current | mask));
3847 return current;
3848 }
3849
3850 @ForceInline
3851 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) {
3852 int current;
3853 do {
3854 // Plain read, the value is a hint, the acquire CAS does the work
3855 current = getInt(o, offset);
3856 } while (!weakCompareAndSetIntAcquire(o, offset,
3857 current, current | mask));
3858 return current;
3859 }
3860
3861 /**
3862 * Atomically replaces the current value of a field or array element within
3863 * the given object with the result of bitwise AND between the current value
3864 * and mask.
3865 *
3866 * @param o object/array to update the field/element in
3867 * @param offset field/element offset
3868 * @param mask the mask value
3869 * @return the previous value
3870 * @since 9
3871 */
3872 @ForceInline
3873 public final int getAndBitwiseAndInt(Object o, long offset, int mask) {
3874 int current;
3875 do {
3876 current = getIntVolatile(o, offset);
3877 } while (!weakCompareAndSetInt(o, offset,
3878 current, current & mask));
3879 return current;
3880 }
3881
3882 @ForceInline
3883 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) {
3884 int current;
3885 do {
3886 current = getInt(o, offset);
3887 } while (!weakCompareAndSetIntRelease(o, offset,
3888 current, current & mask));
3889 return current;
3890 }
3891
3892 @ForceInline
3893 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) {
3894 int current;
3895 do {
3896 // Plain read, the value is a hint, the acquire CAS does the work
3897 current = getInt(o, offset);
3898 } while (!weakCompareAndSetIntAcquire(o, offset,
3899 current, current & mask));
3900 return current;
3901 }
3902
3903 @ForceInline
3904 public final int getAndBitwiseXorInt(Object o, long offset, int mask) {
3905 int current;
3906 do {
3907 current = getIntVolatile(o, offset);
3908 } while (!weakCompareAndSetInt(o, offset,
3909 current, current ^ mask));
3910 return current;
3911 }
3912
3913 @ForceInline
3914 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) {
3915 int current;
3916 do {
3917 current = getInt(o, offset);
3918 } while (!weakCompareAndSetIntRelease(o, offset,
3919 current, current ^ mask));
3920 return current;
3921 }
3922
3923 @ForceInline
3924 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) {
3925 int current;
3926 do {
3927 // Plain read, the value is a hint, the acquire CAS does the work
3928 current = getInt(o, offset);
3929 } while (!weakCompareAndSetIntAcquire(o, offset,
3930 current, current ^ mask));
3931 return current;
3932 }
3933
3934
3935 @ForceInline
3936 public final long getAndBitwiseOrLong(Object o, long offset, long mask) {
3937 long current;
3938 do {
3939 current = getLongVolatile(o, offset);
3940 } while (!weakCompareAndSetLong(o, offset,
3941 current, current | mask));
3942 return current;
3943 }
3944
3945 @ForceInline
3946 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) {
3947 long current;
3948 do {
3949 current = getLong(o, offset);
3950 } while (!weakCompareAndSetLongRelease(o, offset,
3951 current, current | mask));
3952 return current;
3953 }
3954
3955 @ForceInline
3956 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) {
3957 long current;
3958 do {
3959 // Plain read, the value is a hint, the acquire CAS does the work
3960 current = getLong(o, offset);
3961 } while (!weakCompareAndSetLongAcquire(o, offset,
3962 current, current | mask));
3963 return current;
3964 }
3965
3966 @ForceInline
3967 public final long getAndBitwiseAndLong(Object o, long offset, long mask) {
3968 long current;
3969 do {
3970 current = getLongVolatile(o, offset);
3971 } while (!weakCompareAndSetLong(o, offset,
3972 current, current & mask));
3973 return current;
3974 }
3975
3976 @ForceInline
3977 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) {
3978 long current;
3979 do {
3980 current = getLong(o, offset);
3981 } while (!weakCompareAndSetLongRelease(o, offset,
3982 current, current & mask));
3983 return current;
3984 }
3985
3986 @ForceInline
3987 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) {
3988 long current;
3989 do {
3990 // Plain read, the value is a hint, the acquire CAS does the work
3991 current = getLong(o, offset);
3992 } while (!weakCompareAndSetLongAcquire(o, offset,
3993 current, current & mask));
3994 return current;
3995 }
3996
3997 @ForceInline
3998 public final long getAndBitwiseXorLong(Object o, long offset, long mask) {
3999 long current;
4000 do {
4001 current = getLongVolatile(o, offset);
4002 } while (!weakCompareAndSetLong(o, offset,
4003 current, current ^ mask));
4004 return current;
4005 }
4006
4007 @ForceInline
4008 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) {
4009 long current;
4010 do {
4011 current = getLong(o, offset);
4012 } while (!weakCompareAndSetLongRelease(o, offset,
4013 current, current ^ mask));
4014 return current;
4015 }
4016
4017 @ForceInline
4018 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) {
4019 long current;
4020 do {
4021 // Plain read, the value is a hint, the acquire CAS does the work
4022 current = getLong(o, offset);
4023 } while (!weakCompareAndSetLongAcquire(o, offset,
4024 current, current ^ mask));
4025 return current;
4026 }
4027
4028
4029
4030 /**
4031 * Ensures that loads before the fence will not be reordered with loads and
4032 * stores after the fence; a "LoadLoad plus LoadStore barrier".
4033 *
4034 * Corresponds to C11 atomic_thread_fence(memory_order_acquire)
4035 * (an "acquire fence").
4036 *
4037 * Provides a LoadLoad barrier followed by a LoadStore barrier.
4038 *
4039 * @since 1.8
4040 */
4041 @IntrinsicCandidate
4042 public final void loadFence() {
4043 // If loadFence intrinsic is not available, fall back to full fence.
4044 fullFence();
4045 }
4046
4047 /**
4048 * Ensures that loads and stores before the fence will not be reordered with
4049 * stores after the fence; a "StoreStore plus LoadStore barrier".
4050 *
4051 * Corresponds to C11 atomic_thread_fence(memory_order_release)
4052 * (a "release fence").
4053 *
4054 * Provides a StoreStore barrier followed by a LoadStore barrier.
4055 *
4056 * @since 1.8
4057 */
4058 @IntrinsicCandidate
4059 public final void storeFence() {
4060 // If storeFence intrinsic is not available, fall back to full fence.
4061 fullFence();
4062 }
4063
4064 /**
4065 * Ensures that loads and stores before the fence will not be reordered
4066 * with loads and stores after the fence. Implies the effects of both
4067 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad
4068 * barrier.
4069 *
4070 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst).
4071 * @since 1.8
4072 */
4073 @IntrinsicCandidate
4074 public native void fullFence();
4075
4076 /**
4077 * Ensures that loads before the fence will not be reordered with
4078 * loads after the fence.
4079 *
4080 * @implNote
4081 * This method is operationally equivalent to {@link #loadFence()}.
4082 *
4083 * @since 9
4084 */
4085 public final void loadLoadFence() {
4086 loadFence();
4087 }
4088
4089 /**
4090 * Ensures that stores before the fence will not be reordered with
4091 * stores after the fence.
4092 *
4093 * @since 9
4094 */
4095 @IntrinsicCandidate
4096 public final void storeStoreFence() {
4097 // If storeStoreFence intrinsic is not available, fall back to storeFence.
4098 storeFence();
4099 }
4100
4101 /**
4102 * Throws IllegalAccessError; for use by the VM for access control
4103 * error support.
4104 * @since 1.8
4105 */
4106 private static void throwIllegalAccessError() {
4107 throw new IllegalAccessError();
4108 }
4109
4110 /**
4111 * Throws NoSuchMethodError; for use by the VM for redefinition support.
4112 * @since 13
4113 */
4114 private static void throwNoSuchMethodError() {
4115 throw new NoSuchMethodError();
4116 }
4117
4118 /**
4119 * @return Returns true if the native byte ordering of this
4120 * platform is big-endian, false if it is little-endian.
4121 */
4122 public final boolean isBigEndian() { return BIG_ENDIAN; }
4123
4124 /**
4125 * @return Returns true if this platform is capable of performing
4126 * accesses at addresses which are not aligned for the type of the
4127 * primitive type being accessed, false otherwise.
4128 */
4129 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; }
4130
4131 /**
4132 * Fetches a value at some byte offset into a given Java object.
4133 * More specifically, fetches a value within the given object
4134 * <code>o</code> at the given offset, or (if <code>o</code> is
4135 * null) from the memory address whose numerical value is the
4136 * given offset. <p>
4137 *
4138 * The specification of this method is the same as {@link
4139 * #getLong(Object, long)} except that the offset does not need to
4140 * have been obtained from {@link #objectFieldOffset} on the
4141 * {@link java.lang.reflect.Field} of some Java field. The value
4142 * in memory is raw data, and need not correspond to any Java
4143 * variable. Unless <code>o</code> is null, the value accessed
4144 * must be entirely within the allocated object. The endianness
4145 * of the value in memory is the endianness of the native platform.
4146 *
4147 * <p> The read will be atomic with respect to the largest power
4148 * of two that divides the GCD of the offset and the storage size.
4149 * For example, getLongUnaligned will make atomic reads of 2-, 4-,
4150 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4151 * respectively. There are no other guarantees of atomicity.
4152 * <p>
4153 * 8-byte atomicity is only guaranteed on platforms on which
4154 * support atomic accesses to longs.
4155 *
4156 * @param o Java heap object in which the value resides, if any, else
4157 * null
4158 * @param offset The offset in bytes from the start of the object
4159 * @return the value fetched from the indicated object
4160 * @throws RuntimeException No defined exceptions are thrown, not even
4161 * {@link NullPointerException}
4162 * @since 9
4163 */
4164 @IntrinsicCandidate
4165 public final long getLongUnaligned(Object o, long offset) {
4166 if ((offset & 7) == 0) {
4167 return getLong(o, offset);
4168 } else if ((offset & 3) == 0) {
4169 return makeLong(getInt(o, offset),
4170 getInt(o, offset + 4));
4171 } else if ((offset & 1) == 0) {
4172 return makeLong(getShort(o, offset),
4173 getShort(o, offset + 2),
4174 getShort(o, offset + 4),
4175 getShort(o, offset + 6));
4176 } else {
4177 return makeLong(getByte(o, offset),
4178 getByte(o, offset + 1),
4179 getByte(o, offset + 2),
4180 getByte(o, offset + 3),
4181 getByte(o, offset + 4),
4182 getByte(o, offset + 5),
4183 getByte(o, offset + 6),
4184 getByte(o, offset + 7));
4185 }
4186 }
4187 /**
4188 * As {@link #getLongUnaligned(Object, long)} but with an
4189 * additional argument which specifies the endianness of the value
4190 * as stored in memory.
4191 *
4192 * @param o Java heap object in which the variable resides
4193 * @param offset The offset in bytes from the start of the object
4194 * @param bigEndian The endianness of the value
4195 * @return the value fetched from the indicated object
4196 * @since 9
4197 */
4198 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) {
4199 return convEndian(bigEndian, getLongUnaligned(o, offset));
4200 }
4201
4202 /** @see #getLongUnaligned(Object, long) */
4203 @IntrinsicCandidate
4204 public final int getIntUnaligned(Object o, long offset) {
4205 if ((offset & 3) == 0) {
4206 return getInt(o, offset);
4207 } else if ((offset & 1) == 0) {
4208 return makeInt(getShort(o, offset),
4209 getShort(o, offset + 2));
4210 } else {
4211 return makeInt(getByte(o, offset),
4212 getByte(o, offset + 1),
4213 getByte(o, offset + 2),
4214 getByte(o, offset + 3));
4215 }
4216 }
4217 /** @see #getLongUnaligned(Object, long, boolean) */
4218 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) {
4219 return convEndian(bigEndian, getIntUnaligned(o, offset));
4220 }
4221
4222 /** @see #getLongUnaligned(Object, long) */
4223 @IntrinsicCandidate
4224 public final short getShortUnaligned(Object o, long offset) {
4225 if ((offset & 1) == 0) {
4226 return getShort(o, offset);
4227 } else {
4228 return makeShort(getByte(o, offset),
4229 getByte(o, offset + 1));
4230 }
4231 }
4232 /** @see #getLongUnaligned(Object, long, boolean) */
4233 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) {
4234 return convEndian(bigEndian, getShortUnaligned(o, offset));
4235 }
4236
4237 /** @see #getLongUnaligned(Object, long) */
4238 @IntrinsicCandidate
4239 public final char getCharUnaligned(Object o, long offset) {
4240 if ((offset & 1) == 0) {
4241 return getChar(o, offset);
4242 } else {
4243 return (char)makeShort(getByte(o, offset),
4244 getByte(o, offset + 1));
4245 }
4246 }
4247
4248 /** @see #getLongUnaligned(Object, long, boolean) */
4249 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) {
4250 return convEndian(bigEndian, getCharUnaligned(o, offset));
4251 }
4252
4253 /**
4254 * Stores a value at some byte offset into a given Java object.
4255 * <p>
4256 * The specification of this method is the same as {@link
4257 * #getLong(Object, long)} except that the offset does not need to
4258 * have been obtained from {@link #objectFieldOffset} on the
4259 * {@link java.lang.reflect.Field} of some Java field. The value
4260 * in memory is raw data, and need not correspond to any Java
4261 * variable. The endianness of the value in memory is the
4262 * endianness of the native platform.
4263 * <p>
4264 * The write will be atomic with respect to the largest power of
4265 * two that divides the GCD of the offset and the storage size.
4266 * For example, putLongUnaligned will make atomic writes of 2-, 4-,
4267 * or 8-byte storage units if the offset is zero mod 2, 4, or 8,
4268 * respectively. There are no other guarantees of atomicity.
4269 * <p>
4270 * 8-byte atomicity is only guaranteed on platforms on which
4271 * support atomic accesses to longs.
4272 *
4273 * @param o Java heap object in which the value resides, if any, else
4274 * null
4275 * @param offset The offset in bytes from the start of the object
4276 * @param x the value to store
4277 * @throws RuntimeException No defined exceptions are thrown, not even
4278 * {@link NullPointerException}
4279 * @since 9
4280 */
4281 @IntrinsicCandidate
4282 public final void putLongUnaligned(Object o, long offset, long x) {
4283 if ((offset & 7) == 0) {
4284 putLong(o, offset, x);
4285 } else if ((offset & 3) == 0) {
4286 putLongParts(o, offset,
4287 (int)(x >> 0),
4288 (int)(x >>> 32));
4289 } else if ((offset & 1) == 0) {
4290 putLongParts(o, offset,
4291 (short)(x >>> 0),
4292 (short)(x >>> 16),
4293 (short)(x >>> 32),
4294 (short)(x >>> 48));
4295 } else {
4296 putLongParts(o, offset,
4297 (byte)(x >>> 0),
4298 (byte)(x >>> 8),
4299 (byte)(x >>> 16),
4300 (byte)(x >>> 24),
4301 (byte)(x >>> 32),
4302 (byte)(x >>> 40),
4303 (byte)(x >>> 48),
4304 (byte)(x >>> 56));
4305 }
4306 }
4307
4308 /**
4309 * As {@link #putLongUnaligned(Object, long, long)} but with an additional
4310 * argument which specifies the endianness of the value as stored in memory.
4311 * @param o Java heap object in which the value resides
4312 * @param offset The offset in bytes from the start of the object
4313 * @param x the value to store
4314 * @param bigEndian The endianness of the value
4315 * @throws RuntimeException No defined exceptions are thrown, not even
4316 * {@link NullPointerException}
4317 * @since 9
4318 */
4319 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) {
4320 putLongUnaligned(o, offset, convEndian(bigEndian, x));
4321 }
4322
4323 /** @see #putLongUnaligned(Object, long, long) */
4324 @IntrinsicCandidate
4325 public final void putIntUnaligned(Object o, long offset, int x) {
4326 if ((offset & 3) == 0) {
4327 putInt(o, offset, x);
4328 } else if ((offset & 1) == 0) {
4329 putIntParts(o, offset,
4330 (short)(x >> 0),
4331 (short)(x >>> 16));
4332 } else {
4333 putIntParts(o, offset,
4334 (byte)(x >>> 0),
4335 (byte)(x >>> 8),
4336 (byte)(x >>> 16),
4337 (byte)(x >>> 24));
4338 }
4339 }
4340 /** @see #putLongUnaligned(Object, long, long, boolean) */
4341 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) {
4342 putIntUnaligned(o, offset, convEndian(bigEndian, x));
4343 }
4344
4345 /** @see #putLongUnaligned(Object, long, long) */
4346 @IntrinsicCandidate
4347 public final void putShortUnaligned(Object o, long offset, short x) {
4348 if ((offset & 1) == 0) {
4349 putShort(o, offset, x);
4350 } else {
4351 putShortParts(o, offset,
4352 (byte)(x >>> 0),
4353 (byte)(x >>> 8));
4354 }
4355 }
4356 /** @see #putLongUnaligned(Object, long, long, boolean) */
4357 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) {
4358 putShortUnaligned(o, offset, convEndian(bigEndian, x));
4359 }
4360
4361 /** @see #putLongUnaligned(Object, long, long) */
4362 @IntrinsicCandidate
4363 public final void putCharUnaligned(Object o, long offset, char x) {
4364 putShortUnaligned(o, offset, (short)x);
4365 }
4366 /** @see #putLongUnaligned(Object, long, long, boolean) */
4367 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) {
4368 putCharUnaligned(o, offset, convEndian(bigEndian, x));
4369 }
4370
4371 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; }
4372
4373 // These methods construct integers from bytes. The byte ordering
4374 // is the native endianness of this platform.
4375 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4376 return ((toUnsignedLong(i0) << pickPos(56, 0))
4377 | (toUnsignedLong(i1) << pickPos(56, 8))
4378 | (toUnsignedLong(i2) << pickPos(56, 16))
4379 | (toUnsignedLong(i3) << pickPos(56, 24))
4380 | (toUnsignedLong(i4) << pickPos(56, 32))
4381 | (toUnsignedLong(i5) << pickPos(56, 40))
4382 | (toUnsignedLong(i6) << pickPos(56, 48))
4383 | (toUnsignedLong(i7) << pickPos(56, 56)));
4384 }
4385 private static long makeLong(short i0, short i1, short i2, short i3) {
4386 return ((toUnsignedLong(i0) << pickPos(48, 0))
4387 | (toUnsignedLong(i1) << pickPos(48, 16))
4388 | (toUnsignedLong(i2) << pickPos(48, 32))
4389 | (toUnsignedLong(i3) << pickPos(48, 48)));
4390 }
4391 private static long makeLong(int i0, int i1) {
4392 return (toUnsignedLong(i0) << pickPos(32, 0))
4393 | (toUnsignedLong(i1) << pickPos(32, 32));
4394 }
4395 private static int makeInt(short i0, short i1) {
4396 return (toUnsignedInt(i0) << pickPos(16, 0))
4397 | (toUnsignedInt(i1) << pickPos(16, 16));
4398 }
4399 private static int makeInt(byte i0, byte i1, byte i2, byte i3) {
4400 return ((toUnsignedInt(i0) << pickPos(24, 0))
4401 | (toUnsignedInt(i1) << pickPos(24, 8))
4402 | (toUnsignedInt(i2) << pickPos(24, 16))
4403 | (toUnsignedInt(i3) << pickPos(24, 24)));
4404 }
4405 private static short makeShort(byte i0, byte i1) {
4406 return (short)((toUnsignedInt(i0) << pickPos(8, 0))
4407 | (toUnsignedInt(i1) << pickPos(8, 8)));
4408 }
4409
4410 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; }
4411 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; }
4412 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; }
4413
4414 // These methods write integers to memory from smaller parts
4415 // provided by their caller. The ordering in which these parts
4416 // are written is the native endianness of this platform.
4417 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) {
4418 putByte(o, offset + 0, pick(i0, i7));
4419 putByte(o, offset + 1, pick(i1, i6));
4420 putByte(o, offset + 2, pick(i2, i5));
4421 putByte(o, offset + 3, pick(i3, i4));
4422 putByte(o, offset + 4, pick(i4, i3));
4423 putByte(o, offset + 5, pick(i5, i2));
4424 putByte(o, offset + 6, pick(i6, i1));
4425 putByte(o, offset + 7, pick(i7, i0));
4426 }
4427 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) {
4428 putShort(o, offset + 0, pick(i0, i3));
4429 putShort(o, offset + 2, pick(i1, i2));
4430 putShort(o, offset + 4, pick(i2, i1));
4431 putShort(o, offset + 6, pick(i3, i0));
4432 }
4433 private void putLongParts(Object o, long offset, int i0, int i1) {
4434 putInt(o, offset + 0, pick(i0, i1));
4435 putInt(o, offset + 4, pick(i1, i0));
4436 }
4437 private void putIntParts(Object o, long offset, short i0, short i1) {
4438 putShort(o, offset + 0, pick(i0, i1));
4439 putShort(o, offset + 2, pick(i1, i0));
4440 }
4441 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) {
4442 putByte(o, offset + 0, pick(i0, i3));
4443 putByte(o, offset + 1, pick(i1, i2));
4444 putByte(o, offset + 2, pick(i2, i1));
4445 putByte(o, offset + 3, pick(i3, i0));
4446 }
4447 private void putShortParts(Object o, long offset, byte i0, byte i1) {
4448 putByte(o, offset + 0, pick(i0, i1));
4449 putByte(o, offset + 1, pick(i1, i0));
4450 }
4451
4452 // Zero-extend an integer
4453 private static int toUnsignedInt(byte n) { return n & 0xff; }
4454 private static int toUnsignedInt(short n) { return n & 0xffff; }
4455 private static long toUnsignedLong(byte n) { return n & 0xffl; }
4456 private static long toUnsignedLong(short n) { return n & 0xffffl; }
4457 private static long toUnsignedLong(int n) { return n & 0xffffffffl; }
4458
4459 // Maybe byte-reverse an integer
4460 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); }
4461 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
4462 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
4463 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
4464
4465
4466
4467 private native long allocateMemory0(long bytes);
4468 private native long reallocateMemory0(long address, long bytes);
4469 private native void freeMemory0(long address);
4470 @IntrinsicCandidate
4471 private native void setMemory0(Object o, long offset, long bytes, byte value);
4472 @IntrinsicCandidate
4473 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
4474 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
4475 private native long objectFieldOffset0(Field f); // throws IAE
4476 private native long knownObjectFieldOffset0(Class<?> c, String name); // error code: -1 not found, -2 static
4477 private native long staticFieldOffset0(Field f); // throws IAE
4478 private native Object staticFieldBase0(Field f); // throws IAE
4479 private native boolean shouldBeInitialized0(Class<?> c);
4480 private native void ensureClassInitialized0(Class<?> c);
4481 private native void notifyStrictStaticAccess0(Class<?> c, long staticFieldOffset, boolean writing);
4482 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
4483 @IntrinsicCandidate
4484 private native int arrayInstanceBaseOffset0(Object[] array);
4485 private native int arrayIndexScale0(Class<?> arrayClass);
4486 @IntrinsicCandidate
4487 private native int arrayInstanceIndexScale0(Object[] array);
4488 private native long getObjectSize0(Object o);
4489 private native int getLoadAverage0(double[] loadavg, int nelems);
4490 @IntrinsicCandidate
4491 private native int[] getFieldMap0(Class <?> c);
4492
4493
4494 /**
4495 * Invokes the given direct byte buffer's cleaner, if any.
4496 *
4497 * @param directBuffer a direct byte buffer
4498 * @throws NullPointerException if {@code directBuffer} is null
4499 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
4500 * or is a {@link java.nio.Buffer#slice slice}, or is a
4501 * {@link java.nio.Buffer#duplicate duplicate}
4502 */
4503 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
4504 if (!directBuffer.isDirect())
4505 throw new IllegalArgumentException("buffer is non-direct");
4506
4507 DirectBuffer db = (DirectBuffer) directBuffer;
4508 if (db.attachment() != null)
4509 throw new IllegalArgumentException("duplicate or slice");
4510
4511 Cleaner cleaner = db.cleaner();
4512 if (cleaner != null) {
4513 cleaner.clean();
4514 }
4515 }
4516 }