1 /* 2 * Copyright (c) 2000, 2024, 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.ref.Cleaner; 29 import jdk.internal.vm.annotation.ForceInline; 30 import jdk.internal.vm.annotation.IntrinsicCandidate; 31 import sun.nio.ch.DirectBuffer; 32 33 import java.lang.reflect.Field; 34 import java.security.ProtectionDomain; 35 36 import static jdk.internal.misc.UnsafeConstants.*; 37 38 /** 39 * A collection of methods for performing low-level, unsafe operations. 40 * Although the class and all methods are public, use of this class is 41 * limited because only trusted code can obtain instances of it. 42 * 43 * <em>Note:</em> It is the responsibility of the caller to make sure 44 * arguments are checked before methods of this class are 45 * called. While some rudimentary checks are performed on the input, 46 * the checks are best effort and when performance is an overriding 47 * priority, as when methods of this class are optimized by the 48 * runtime compiler, some or all checks (if any) may be elided. Hence, 49 * the caller must not rely on the checks and corresponding 50 * exceptions! 51 * 52 * @author John R. Rose 53 * @see #getUnsafe 54 */ 55 56 public final class Unsafe { 57 58 private static native void registerNatives(); 59 static { 60 runtimeSetup(); 61 } 62 63 // Called from JVM when loading an AOT cache 64 private static void runtimeSetup() { 65 registerNatives(); 66 } 67 68 private Unsafe() {} 69 70 private static final Unsafe theUnsafe = new Unsafe(); 71 72 /** 73 * Provides the caller with the capability of performing unsafe 74 * operations. 75 * 76 * <p>The returned {@code Unsafe} object should be carefully guarded 77 * by the caller, since it can be used to read and write data at arbitrary 78 * memory addresses. It must never be passed to untrusted code. 79 * 80 * <p>Most methods in this class are very low-level, and correspond to a 81 * small number of hardware instructions (on typical machines). Compilers 82 * are encouraged to optimize these methods accordingly. 83 * 84 * <p>Here is a suggested idiom for using unsafe operations: 85 * 86 * <pre> {@code 87 * class MyTrustedClass { 88 * private static final Unsafe unsafe = Unsafe.getUnsafe(); 89 * ... 90 * private long myCountAddress = ...; 91 * public int getCount() { return unsafe.getByte(myCountAddress); } 92 * }}</pre> 93 * 94 * (It may assist compilers to make the local variable {@code final}.) 95 */ 96 public static Unsafe getUnsafe() { 97 return theUnsafe; 98 } 99 100 //--- peek and poke operations 101 // (compilers should optimize these to memory ops) 102 103 // These work on object fields in the Java heap. 104 // They will not work on elements of packed arrays. 105 106 /** 107 * Fetches a value from a given Java variable. 108 * More specifically, fetches a field or array element within the given 109 * object {@code o} at the given offset, or (if {@code o} is null) 110 * from the memory address whose numerical value is the given offset. 111 * <p> 112 * The results are undefined unless one of the following cases is true: 113 * <ul> 114 * <li>The offset was obtained from {@link #objectFieldOffset} on 115 * the {@link java.lang.reflect.Field} of some Java field and the object 116 * referred to by {@code o} is of a class compatible with that 117 * field's class. 118 * 119 * <li>The offset and object reference {@code o} (either null or 120 * non-null) were both obtained via {@link #staticFieldOffset} 121 * and {@link #staticFieldBase} (respectively) from the 122 * reflective {@link Field} representation of some Java field. 123 * 124 * <li>The object referred to by {@code o} is an array, and the offset 125 * is an integer of the form {@code B+N*S}, where {@code N} is 126 * a valid index into the array, and {@code B} and {@code S} are 127 * the values obtained by {@link #arrayBaseOffset} and {@link 128 * #arrayIndexScale} (respectively) from the array's class. The value 129 * referred to is the {@code N}<em>th</em> element of the array. 130 * 131 * </ul> 132 * <p> 133 * If one of the above cases is true, the call references a specific Java 134 * variable (field or array element). However, the results are undefined 135 * if that variable is not in fact of the type returned by this method. 136 * <p> 137 * This method refers to a variable by means of two parameters, and so 138 * it provides (in effect) a <em>double-register</em> addressing mode 139 * for Java variables. When the object reference is null, this method 140 * uses its offset as an absolute address. This is similar in operation 141 * to methods such as {@link #getInt(long)}, which provide (in effect) a 142 * <em>single-register</em> addressing mode for non-Java variables. 143 * However, because Java variables may have a different layout in memory 144 * from non-Java variables, programmers should not assume that these 145 * two addressing modes are ever equivalent. Also, programmers should 146 * remember that offsets from the double-register addressing mode cannot 147 * be portably confused with longs used in the single-register addressing 148 * mode. 149 * 150 * @param o Java heap object in which the variable resides, if any, else 151 * null 152 * @param offset indication of where the variable resides in a Java heap 153 * object, if any, else a memory address locating the variable 154 * statically 155 * @return the value fetched from the indicated Java variable 156 * @throws RuntimeException No defined exceptions are thrown, not even 157 * {@link NullPointerException} 158 */ 159 @IntrinsicCandidate 160 public native int getInt(Object o, long offset); 161 162 /** 163 * Stores a value into a given Java variable. 164 * <p> 165 * The first two parameters are interpreted exactly as with 166 * {@link #getInt(Object, long)} to refer to a specific 167 * Java variable (field or array element). The given value 168 * is stored into that variable. 169 * <p> 170 * The variable must be of the same type as the method 171 * parameter {@code x}. 172 * 173 * @param o Java heap object in which the variable resides, if any, else 174 * null 175 * @param offset indication of where the variable resides in a Java heap 176 * object, if any, else a memory address locating the variable 177 * statically 178 * @param x the value to store into the indicated Java variable 179 * @throws RuntimeException No defined exceptions are thrown, not even 180 * {@link NullPointerException} 181 */ 182 @IntrinsicCandidate 183 public native void putInt(Object o, long offset, int x); 184 185 /** 186 * Fetches a reference value from a given Java variable. 187 * @see #getInt(Object, long) 188 */ 189 @IntrinsicCandidate 190 public native Object getReference(Object o, long offset); 191 192 /** 193 * Stores a reference value into a given Java variable. 194 * <p> 195 * Unless the reference {@code x} being stored is either null 196 * or matches the field type, the results are undefined. 197 * If the reference {@code o} is non-null, card marks or 198 * other store barriers for that object (if the VM requires them) 199 * are updated. 200 * @see #putInt(Object, long, int) 201 */ 202 @IntrinsicCandidate 203 public native void putReference(Object o, long offset, Object x); 204 205 /** @see #getInt(Object, long) */ 206 @IntrinsicCandidate 207 public native boolean getBoolean(Object o, long offset); 208 209 /** @see #putInt(Object, long, int) */ 210 @IntrinsicCandidate 211 public native void putBoolean(Object o, long offset, boolean x); 212 213 /** @see #getInt(Object, long) */ 214 @IntrinsicCandidate 215 public native byte getByte(Object o, long offset); 216 217 /** @see #putInt(Object, long, int) */ 218 @IntrinsicCandidate 219 public native void putByte(Object o, long offset, byte x); 220 221 /** @see #getInt(Object, long) */ 222 @IntrinsicCandidate 223 public native short getShort(Object o, long offset); 224 225 /** @see #putInt(Object, long, int) */ 226 @IntrinsicCandidate 227 public native void putShort(Object o, long offset, short x); 228 229 /** @see #getInt(Object, long) */ 230 @IntrinsicCandidate 231 public native char getChar(Object o, long offset); 232 233 /** @see #putInt(Object, long, int) */ 234 @IntrinsicCandidate 235 public native void putChar(Object o, long offset, char x); 236 237 /** @see #getInt(Object, long) */ 238 @IntrinsicCandidate 239 public native long getLong(Object o, long offset); 240 241 /** @see #putInt(Object, long, int) */ 242 @IntrinsicCandidate 243 public native void putLong(Object o, long offset, long x); 244 245 /** @see #getInt(Object, long) */ 246 @IntrinsicCandidate 247 public native float getFloat(Object o, long offset); 248 249 /** @see #putInt(Object, long, int) */ 250 @IntrinsicCandidate 251 public native void putFloat(Object o, long offset, float x); 252 253 /** @see #getInt(Object, long) */ 254 @IntrinsicCandidate 255 public native double getDouble(Object o, long offset); 256 257 /** @see #putInt(Object, long, int) */ 258 @IntrinsicCandidate 259 public native void putDouble(Object o, long offset, double x); 260 261 /** 262 * Fetches a native pointer from a given memory address. If the address is 263 * zero, or does not point into a block obtained from {@link 264 * #allocateMemory}, the results are undefined. 265 * 266 * <p>If the native pointer is less than 64 bits wide, it is extended as 267 * an unsigned number to a Java long. The pointer may be indexed by any 268 * given byte offset, simply by adding that offset (as a simple integer) to 269 * the long representing the pointer. The number of bytes actually read 270 * from the target address may be determined by consulting {@link 271 * #addressSize}. 272 * 273 * @see #allocateMemory 274 * @see #getInt(Object, long) 275 */ 276 @ForceInline 277 public long getAddress(Object o, long offset) { 278 if (ADDRESS_SIZE == 4) { 279 return Integer.toUnsignedLong(getInt(o, offset)); 280 } else { 281 return getLong(o, offset); 282 } 283 } 284 285 /** 286 * Stores a native pointer into a given memory address. If the address is 287 * zero, or does not point into a block obtained from {@link 288 * #allocateMemory}, the results are undefined. 289 * 290 * <p>The number of bytes actually written at the target address may be 291 * determined by consulting {@link #addressSize}. 292 * 293 * @see #allocateMemory 294 * @see #putInt(Object, long, int) 295 */ 296 @ForceInline 297 public void putAddress(Object o, long offset, long x) { 298 if (ADDRESS_SIZE == 4) { 299 putInt(o, offset, (int)x); 300 } else { 301 putLong(o, offset, x); 302 } 303 } 304 305 // These read VM internal data. 306 307 /** 308 * Fetches an uncompressed reference value from a given native variable 309 * ignoring the VM's compressed references mode. 310 * 311 * @param address a memory address locating the variable 312 * @return the value fetched from the indicated native variable 313 */ 314 public native Object getUncompressedObject(long address); 315 316 // These work on values in the C heap. 317 318 /** 319 * Fetches a value from a given memory address. If the address is zero, or 320 * does not point into a block obtained from {@link #allocateMemory}, the 321 * results are undefined. 322 * 323 * @see #allocateMemory 324 */ 325 @ForceInline 326 public byte getByte(long address) { 327 return getByte(null, address); 328 } 329 330 /** 331 * Stores a value into a given memory address. If the address is zero, or 332 * does not point into a block obtained from {@link #allocateMemory}, the 333 * results are undefined. 334 * 335 * @see #getByte(long) 336 */ 337 @ForceInline 338 public void putByte(long address, byte x) { 339 putByte(null, address, x); 340 } 341 342 /** @see #getByte(long) */ 343 @ForceInline 344 public short getShort(long address) { 345 return getShort(null, address); 346 } 347 348 /** @see #putByte(long, byte) */ 349 @ForceInline 350 public void putShort(long address, short x) { 351 putShort(null, address, x); 352 } 353 354 /** @see #getByte(long) */ 355 @ForceInline 356 public char getChar(long address) { 357 return getChar(null, address); 358 } 359 360 /** @see #putByte(long, byte) */ 361 @ForceInline 362 public void putChar(long address, char x) { 363 putChar(null, address, x); 364 } 365 366 /** @see #getByte(long) */ 367 @ForceInline 368 public int getInt(long address) { 369 return getInt(null, address); 370 } 371 372 /** @see #putByte(long, byte) */ 373 @ForceInline 374 public void putInt(long address, int x) { 375 putInt(null, address, x); 376 } 377 378 /** @see #getByte(long) */ 379 @ForceInline 380 public long getLong(long address) { 381 return getLong(null, address); 382 } 383 384 /** @see #putByte(long, byte) */ 385 @ForceInline 386 public void putLong(long address, long x) { 387 putLong(null, address, x); 388 } 389 390 /** @see #getByte(long) */ 391 @ForceInline 392 public float getFloat(long address) { 393 return getFloat(null, address); 394 } 395 396 /** @see #putByte(long, byte) */ 397 @ForceInline 398 public void putFloat(long address, float x) { 399 putFloat(null, address, x); 400 } 401 402 /** @see #getByte(long) */ 403 @ForceInline 404 public double getDouble(long address) { 405 return getDouble(null, address); 406 } 407 408 /** @see #putByte(long, byte) */ 409 @ForceInline 410 public void putDouble(long address, double x) { 411 putDouble(null, address, x); 412 } 413 414 /** @see #getAddress(Object, long) */ 415 @ForceInline 416 public long getAddress(long address) { 417 return getAddress(null, address); 418 } 419 420 /** @see #putAddress(Object, long, long) */ 421 @ForceInline 422 public void putAddress(long address, long x) { 423 putAddress(null, address, x); 424 } 425 426 427 428 //--- helper methods for validating various types of objects/values 429 430 /** 431 * Create an exception reflecting that some of the input was invalid 432 * 433 * <em>Note:</em> It is the responsibility of the caller to make 434 * sure arguments are checked before the methods are called. While 435 * some rudimentary checks are performed on the input, the checks 436 * are best effort and when performance is an overriding priority, 437 * as when methods of this class are optimized by the runtime 438 * compiler, some or all checks (if any) may be elided. Hence, the 439 * caller must not rely on the checks and corresponding 440 * exceptions! 441 * 442 * @return an exception object 443 */ 444 private RuntimeException invalidInput() { 445 return new IllegalArgumentException(); 446 } 447 448 /** 449 * Check if a value is 32-bit clean (32 MSB are all zero) 450 * 451 * @param value the 64-bit value to check 452 * 453 * @return true if the value is 32-bit clean 454 */ 455 private boolean is32BitClean(long value) { 456 return value >>> 32 == 0; 457 } 458 459 /** 460 * Check the validity of a size (the equivalent of a size_t) 461 * 462 * @throws RuntimeException if the size is invalid 463 * (<em>Note:</em> after optimization, invalid inputs may 464 * go undetected, which will lead to unpredictable 465 * behavior) 466 */ 467 private void checkSize(long size) { 468 if (ADDRESS_SIZE == 4) { 469 // Note: this will also check for negative sizes 470 if (!is32BitClean(size)) { 471 throw invalidInput(); 472 } 473 } else if (size < 0) { 474 throw invalidInput(); 475 } 476 } 477 478 /** 479 * Check the validity of a native address (the equivalent of void*) 480 * 481 * @throws RuntimeException if the address is invalid 482 * (<em>Note:</em> after optimization, invalid inputs may 483 * go undetected, which will lead to unpredictable 484 * behavior) 485 */ 486 private void checkNativeAddress(long address) { 487 if (ADDRESS_SIZE == 4) { 488 // Accept both zero and sign extended pointers. A valid 489 // pointer will, after the +1 below, either have produced 490 // the value 0x0 or 0x1. Masking off the low bit allows 491 // for testing against 0. 492 if ((((address >> 32) + 1) & ~1) != 0) { 493 throw invalidInput(); 494 } 495 } 496 } 497 498 /** 499 * Check the validity of an offset, relative to a base object 500 * 501 * @param o the base object 502 * @param offset the offset to check 503 * 504 * @throws RuntimeException if the size is invalid 505 * (<em>Note:</em> after optimization, invalid inputs may 506 * go undetected, which will lead to unpredictable 507 * behavior) 508 */ 509 private void checkOffset(Object o, long offset) { 510 if (ADDRESS_SIZE == 4) { 511 // Note: this will also check for negative offsets 512 if (!is32BitClean(offset)) { 513 throw invalidInput(); 514 } 515 } else if (offset < 0) { 516 throw invalidInput(); 517 } 518 } 519 520 /** 521 * Check the validity of a double-register pointer 522 * 523 * Note: This code deliberately does *not* check for NPE for (at 524 * least) three reasons: 525 * 526 * 1) NPE is not just NULL/0 - there is a range of values all 527 * resulting in an NPE, which is not trivial to check for 528 * 529 * 2) It is the responsibility of the callers of Unsafe methods 530 * to verify the input, so throwing an exception here is not really 531 * useful - passing in a NULL pointer is a critical error and the 532 * must not expect an exception to be thrown anyway. 533 * 534 * 3) the actual operations will detect NULL pointers anyway by 535 * means of traps and signals (like SIGSEGV). 536 * 537 * @param o Java heap object, or null 538 * @param offset indication of where the variable resides in a Java heap 539 * object, if any, else a memory address locating the variable 540 * statically 541 * 542 * @throws RuntimeException if the pointer is invalid 543 * (<em>Note:</em> after optimization, invalid inputs may 544 * go undetected, which will lead to unpredictable 545 * behavior) 546 */ 547 private void checkPointer(Object o, long offset) { 548 if (o == null) { 549 checkNativeAddress(offset); 550 } else { 551 checkOffset(o, offset); 552 } 553 } 554 555 /** 556 * Check if a type is a primitive array type 557 * 558 * @param c the type to check 559 * 560 * @return true if the type is a primitive array type 561 */ 562 private void checkPrimitiveArray(Class<?> c) { 563 Class<?> componentType = c.getComponentType(); 564 if (componentType == null || !componentType.isPrimitive()) { 565 throw invalidInput(); 566 } 567 } 568 569 /** 570 * Check that a pointer is a valid primitive array type pointer 571 * 572 * Note: pointers off-heap are considered to be primitive arrays 573 * 574 * @throws RuntimeException if the pointer is invalid 575 * (<em>Note:</em> after optimization, invalid inputs may 576 * go undetected, which will lead to unpredictable 577 * behavior) 578 */ 579 private void checkPrimitivePointer(Object o, long offset) { 580 checkPointer(o, offset); 581 582 if (o != null) { 583 // If on heap, it must be a primitive array 584 checkPrimitiveArray(o.getClass()); 585 } 586 } 587 588 589 //--- wrappers for malloc, realloc, free: 590 591 /** 592 * Round up allocation size to a multiple of HeapWordSize. 593 */ 594 private long alignToHeapWordSize(long bytes) { 595 if (bytes >= 0) { 596 return (bytes + ADDRESS_SIZE - 1) & ~(ADDRESS_SIZE - 1); 597 } else { 598 throw invalidInput(); 599 } 600 } 601 602 /** 603 * Allocates a new block of native memory, of the given size in bytes. The 604 * contents of the memory are uninitialized; they will generally be 605 * garbage. The resulting native pointer will be zero if and only if the 606 * requested size is zero. The resulting native pointer will be aligned for 607 * all value types. Dispose of this memory by calling {@link #freeMemory} 608 * or resize it with {@link #reallocateMemory}. 609 * 610 * <em>Note:</em> It is the responsibility of the caller to make 611 * sure arguments are checked before the methods are called. While 612 * some rudimentary checks are performed on the input, the checks 613 * are best effort and when performance is an overriding priority, 614 * as when methods of this class are optimized by the runtime 615 * compiler, some or all checks (if any) may be elided. Hence, the 616 * caller must not rely on the checks and corresponding 617 * exceptions! 618 * 619 * @throws RuntimeException if the size is negative or too large 620 * for the native size_t type 621 * 622 * @throws OutOfMemoryError if the allocation is refused by the system 623 * 624 * @see #getByte(long) 625 * @see #putByte(long, byte) 626 */ 627 public long allocateMemory(long bytes) { 628 bytes = alignToHeapWordSize(bytes); 629 630 allocateMemoryChecks(bytes); 631 632 if (bytes == 0) { 633 return 0; 634 } 635 636 long p = allocateMemory0(bytes); 637 if (p == 0) { 638 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes"); 639 } 640 641 return p; 642 } 643 644 /** 645 * Validate the arguments to allocateMemory 646 * 647 * @throws RuntimeException if the arguments are invalid 648 * (<em>Note:</em> after optimization, invalid inputs may 649 * go undetected, which will lead to unpredictable 650 * behavior) 651 */ 652 private void allocateMemoryChecks(long bytes) { 653 checkSize(bytes); 654 } 655 656 /** 657 * Resizes a new block of native memory, to the given size in bytes. The 658 * contents of the new block past the size of the old block are 659 * uninitialized; they will generally be garbage. The resulting native 660 * pointer will be zero if and only if the requested size is zero. The 661 * resulting native pointer will be aligned for all value types. Dispose 662 * of this memory by calling {@link #freeMemory}, or resize it with {@link 663 * #reallocateMemory}. The address passed to this method may be null, in 664 * which case an allocation will be performed. 665 * 666 * <em>Note:</em> It is the responsibility of the caller to make 667 * sure arguments are checked before the methods are called. While 668 * some rudimentary checks are performed on the input, the checks 669 * are best effort and when performance is an overriding priority, 670 * as when methods of this class are optimized by the runtime 671 * compiler, some or all checks (if any) may be elided. Hence, the 672 * caller must not rely on the checks and corresponding 673 * exceptions! 674 * 675 * @throws RuntimeException if the size is negative or too large 676 * for the native size_t type 677 * 678 * @throws OutOfMemoryError if the allocation is refused by the system 679 * 680 * @see #allocateMemory 681 */ 682 public long reallocateMemory(long address, long bytes) { 683 bytes = alignToHeapWordSize(bytes); 684 685 reallocateMemoryChecks(address, bytes); 686 687 if (bytes == 0) { 688 freeMemory(address); 689 return 0; 690 } 691 692 long p = (address == 0) ? allocateMemory0(bytes) : reallocateMemory0(address, bytes); 693 if (p == 0) { 694 throw new OutOfMemoryError("Unable to allocate " + bytes + " bytes"); 695 } 696 697 return p; 698 } 699 700 /** 701 * Validate the arguments to reallocateMemory 702 * 703 * @throws RuntimeException if the arguments are invalid 704 * (<em>Note:</em> after optimization, invalid inputs may 705 * go undetected, which will lead to unpredictable 706 * behavior) 707 */ 708 private void reallocateMemoryChecks(long address, long bytes) { 709 checkPointer(null, address); 710 checkSize(bytes); 711 } 712 713 /** 714 * Sets all bytes in a given block of memory to a fixed value 715 * (usually zero). 716 * 717 * <p>This method determines a block's base address by means of two parameters, 718 * and so it provides (in effect) a <em>double-register</em> addressing mode, 719 * as discussed in {@link #getInt(Object,long)}. When the object reference is null, 720 * the offset supplies an absolute base address. 721 * 722 * <p>The stores are in coherent (atomic) units of a size determined 723 * by the address and length parameters. If the effective address and 724 * length are all even modulo 8, the stores take place in 'long' units. 725 * If the effective address and length are (resp.) even modulo 4 or 2, 726 * the stores take place in units of 'int' or 'short'. 727 * 728 * <em>Note:</em> It is the responsibility of the caller to make 729 * sure arguments are checked before the methods are called. While 730 * some rudimentary checks are performed on the input, the checks 731 * are best effort and when performance is an overriding priority, 732 * as when methods of this class are optimized by the runtime 733 * compiler, some or all checks (if any) may be elided. Hence, the 734 * caller must not rely on the checks and corresponding 735 * exceptions! 736 * 737 * @throws RuntimeException if any of the arguments is invalid 738 * 739 * @since 1.7 740 */ 741 public void setMemory(Object o, long offset, long bytes, byte value) { 742 setMemoryChecks(o, offset, bytes, value); 743 744 if (bytes == 0) { 745 return; 746 } 747 748 setMemory0(o, offset, bytes, value); 749 } 750 751 /** 752 * Sets all bytes in a given block of memory to a fixed value 753 * (usually zero). This provides a <em>single-register</em> addressing mode, 754 * as discussed in {@link #getInt(Object,long)}. 755 * 756 * <p>Equivalent to {@code setMemory(null, address, bytes, value)}. 757 */ 758 public void setMemory(long address, long bytes, byte value) { 759 setMemory(null, address, bytes, value); 760 } 761 762 /** 763 * Validate the arguments to setMemory 764 * 765 * @throws RuntimeException if the arguments are invalid 766 * (<em>Note:</em> after optimization, invalid inputs may 767 * go undetected, which will lead to unpredictable 768 * behavior) 769 */ 770 private void setMemoryChecks(Object o, long offset, long bytes, byte value) { 771 checkPrimitivePointer(o, offset); 772 checkSize(bytes); 773 } 774 775 /** 776 * Sets all bytes in a given block of memory to a copy of another 777 * block. 778 * 779 * <p>This method determines each block's base address by means of two parameters, 780 * and so it provides (in effect) a <em>double-register</em> addressing mode, 781 * as discussed in {@link #getInt(Object,long)}. When the object reference is null, 782 * the offset supplies an absolute base address. 783 * 784 * <p>The transfers are in coherent (atomic) units of a size determined 785 * by the address and length parameters. If the effective addresses and 786 * length are all even modulo 8, the transfer takes place in 'long' units. 787 * If the effective addresses and length are (resp.) even modulo 4 or 2, 788 * the transfer takes place in units of 'int' or 'short'. 789 * 790 * <em>Note:</em> It is the responsibility of the caller to make 791 * sure arguments are checked before the methods are called. While 792 * some rudimentary checks are performed on the input, the checks 793 * are best effort and when performance is an overriding priority, 794 * as when methods of this class are optimized by the runtime 795 * compiler, some or all checks (if any) may be elided. Hence, the 796 * caller must not rely on the checks and corresponding 797 * exceptions! 798 * 799 * @throws RuntimeException if any of the arguments is invalid 800 * 801 * @since 1.7 802 */ 803 public void copyMemory(Object srcBase, long srcOffset, 804 Object destBase, long destOffset, 805 long bytes) { 806 copyMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes); 807 808 if (bytes == 0) { 809 return; 810 } 811 812 copyMemory0(srcBase, srcOffset, destBase, destOffset, bytes); 813 } 814 815 /** 816 * Sets all bytes in a given block of memory to a copy of another 817 * block. This provides a <em>single-register</em> addressing mode, 818 * as discussed in {@link #getInt(Object,long)}. 819 * 820 * Equivalent to {@code copyMemory(null, srcAddress, null, destAddress, bytes)}. 821 */ 822 public void copyMemory(long srcAddress, long destAddress, long bytes) { 823 copyMemory(null, srcAddress, null, destAddress, bytes); 824 } 825 826 /** 827 * Validate the arguments to copyMemory 828 * 829 * @throws RuntimeException if any of the arguments is invalid 830 * (<em>Note:</em> after optimization, invalid inputs may 831 * go undetected, which will lead to unpredictable 832 * behavior) 833 */ 834 private void copyMemoryChecks(Object srcBase, long srcOffset, 835 Object destBase, long destOffset, 836 long bytes) { 837 checkSize(bytes); 838 checkPrimitivePointer(srcBase, srcOffset); 839 checkPrimitivePointer(destBase, destOffset); 840 } 841 842 /** 843 * Copies all elements from one block of memory to another block, 844 * *unconditionally* byte swapping the elements on the fly. 845 * 846 * <p>This method determines each block's base address by means of two parameters, 847 * and so it provides (in effect) a <em>double-register</em> addressing mode, 848 * as discussed in {@link #getInt(Object,long)}. When the object reference is null, 849 * the offset supplies an absolute base address. 850 * 851 * <em>Note:</em> It is the responsibility of the caller to make 852 * sure arguments are checked before the methods are called. While 853 * some rudimentary checks are performed on the input, the checks 854 * are best effort and when performance is an overriding priority, 855 * as when methods of this class are optimized by the runtime 856 * compiler, some or all checks (if any) may be elided. Hence, the 857 * caller must not rely on the checks and corresponding 858 * exceptions! 859 * 860 * @throws RuntimeException if any of the arguments is invalid 861 * 862 * @since 9 863 */ 864 public void copySwapMemory(Object srcBase, long srcOffset, 865 Object destBase, long destOffset, 866 long bytes, long elemSize) { 867 copySwapMemoryChecks(srcBase, srcOffset, destBase, destOffset, bytes, elemSize); 868 869 if (bytes == 0) { 870 return; 871 } 872 873 copySwapMemory0(srcBase, srcOffset, destBase, destOffset, bytes, elemSize); 874 } 875 876 private void copySwapMemoryChecks(Object srcBase, long srcOffset, 877 Object destBase, long destOffset, 878 long bytes, long elemSize) { 879 checkSize(bytes); 880 881 if (elemSize != 2 && elemSize != 4 && elemSize != 8) { 882 throw invalidInput(); 883 } 884 if (bytes % elemSize != 0) { 885 throw invalidInput(); 886 } 887 888 checkPrimitivePointer(srcBase, srcOffset); 889 checkPrimitivePointer(destBase, destOffset); 890 } 891 892 /** 893 * Copies all elements from one block of memory to another block, byte swapping the 894 * elements on the fly. 895 * 896 * This provides a <em>single-register</em> addressing mode, as 897 * discussed in {@link #getInt(Object,long)}. 898 * 899 * Equivalent to {@code copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize)}. 900 */ 901 public void copySwapMemory(long srcAddress, long destAddress, long bytes, long elemSize) { 902 copySwapMemory(null, srcAddress, null, destAddress, bytes, elemSize); 903 } 904 905 /** 906 * Disposes of a block of native memory, as obtained from {@link 907 * #allocateMemory} or {@link #reallocateMemory}. The address passed to 908 * this method may be null, in which case no action is taken. 909 * 910 * <em>Note:</em> It is the responsibility of the caller to make 911 * sure arguments are checked before the methods are called. While 912 * some rudimentary checks are performed on the input, the checks 913 * are best effort and when performance is an overriding priority, 914 * as when methods of this class are optimized by the runtime 915 * compiler, some or all checks (if any) may be elided. Hence, the 916 * caller must not rely on the checks and corresponding 917 * exceptions! 918 * 919 * @throws RuntimeException if any of the arguments is invalid 920 * 921 * @see #allocateMemory 922 */ 923 public void freeMemory(long address) { 924 freeMemoryChecks(address); 925 926 if (address == 0) { 927 return; 928 } 929 930 freeMemory0(address); 931 } 932 933 /** 934 * Validate the arguments to freeMemory 935 * 936 * @throws RuntimeException if the arguments are invalid 937 * (<em>Note:</em> after optimization, invalid inputs may 938 * go undetected, which will lead to unpredictable 939 * behavior) 940 */ 941 private void freeMemoryChecks(long address) { 942 checkPointer(null, address); 943 } 944 945 /** 946 * Ensure writeback of a specified virtual memory address range 947 * from cache to physical memory. All bytes in the address range 948 * are guaranteed to have been written back to physical memory on 949 * return from this call i.e. subsequently executed store 950 * instructions are guaranteed not to be visible before the 951 * writeback is completed. 952 * 953 * @param address 954 * the lowest byte address that must be guaranteed written 955 * back to memory. bytes at lower addresses may also be 956 * written back. 957 * 958 * @param length 959 * the length in bytes of the region starting at address 960 * that must be guaranteed written back to memory. 961 * 962 * @throws RuntimeException if memory writeback is not supported 963 * on the current hardware of if the arguments are invalid. 964 * (<em>Note:</em> after optimization, invalid inputs may 965 * go undetected, which will lead to unpredictable 966 * behavior) 967 * 968 * @since 14 969 */ 970 971 public void writebackMemory(long address, long length) { 972 checkWritebackEnabled(); 973 checkWritebackMemory(address, length); 974 975 // perform any required pre-writeback barrier 976 writebackPreSync0(); 977 978 // write back one cache line at a time 979 long line = dataCacheLineAlignDown(address); 980 long end = address + length; 981 while (line < end) { 982 writeback0(line); 983 line += dataCacheLineFlushSize(); 984 } 985 986 // perform any required post-writeback barrier 987 writebackPostSync0(); 988 } 989 990 /** 991 * Validate the arguments to writebackMemory 992 * 993 * @throws RuntimeException if the arguments are invalid 994 * (<em>Note:</em> after optimization, invalid inputs may 995 * go undetected, which will lead to unpredictable 996 * behavior) 997 */ 998 private void checkWritebackMemory(long address, long length) { 999 checkNativeAddress(address); 1000 checkSize(length); 1001 } 1002 1003 /** 1004 * Validate that the current hardware supports memory writeback. 1005 * (<em>Note:</em> this is a belt and braces check. Clients are 1006 * expected to test whether writeback is enabled by calling 1007 * ({@link isWritebackEnabled #isWritebackEnabled} and avoid 1008 * calling method {@link writeback #writeback} if it is disabled). 1009 * 1010 * 1011 * @throws RuntimeException if memory writeback is not supported 1012 */ 1013 private void checkWritebackEnabled() { 1014 if (!isWritebackEnabled()) { 1015 throw new RuntimeException("writebackMemory not enabled!"); 1016 } 1017 } 1018 1019 /** 1020 * force writeback of an individual cache line. 1021 * 1022 * @param address 1023 * the start address of the cache line to be written back 1024 */ 1025 @IntrinsicCandidate 1026 private native void writeback0(long address); 1027 1028 /** 1029 * Serialize writeback operations relative to preceding memory writes. 1030 */ 1031 @IntrinsicCandidate 1032 private native void writebackPreSync0(); 1033 1034 /** 1035 * Serialize writeback operations relative to following memory writes. 1036 */ 1037 @IntrinsicCandidate 1038 private native void writebackPostSync0(); 1039 1040 //--- random queries 1041 1042 /** 1043 * This constant differs from all results that will ever be returned from 1044 * {@link #staticFieldOffset}, {@link #objectFieldOffset}, 1045 * or {@link #arrayBaseOffset}. 1046 */ 1047 public static final int INVALID_FIELD_OFFSET = -1; 1048 1049 /** 1050 * Reports the location of a given field in the storage allocation of its 1051 * class. Do not expect to perform any sort of arithmetic on this offset; 1052 * it is just a cookie which is passed to the unsafe heap memory accessors. 1053 * 1054 * <p>Any given field will always have the same offset and base, and no 1055 * two distinct fields of the same class will ever have the same offset 1056 * and base. 1057 * 1058 * <p>As of 1.4.1, offsets for fields are represented as long values, 1059 * although the Sun JVM does not use the most significant 32 bits. 1060 * However, JVM implementations which store static fields at absolute 1061 * addresses can use long offsets and null base pointers to express 1062 * the field locations in a form usable by {@link #getInt(Object,long)}. 1063 * Therefore, code which will be ported to such JVMs on 64-bit platforms 1064 * must preserve all bits of static field offsets. 1065 * @see #getInt(Object, long) 1066 */ 1067 public long objectFieldOffset(Field f) { 1068 if (f == null) { 1069 throw new NullPointerException(); 1070 } 1071 1072 return objectFieldOffset0(f); 1073 } 1074 1075 /** 1076 * Reports the location of the field with a given name in the storage 1077 * allocation of its class. 1078 * 1079 * @throws NullPointerException if any parameter is {@code null}. 1080 * @throws InternalError if there is no field named {@code name} declared 1081 * in class {@code c}, i.e., if {@code c.getDeclaredField(name)} 1082 * would throw {@code java.lang.NoSuchFieldException}. 1083 * 1084 * @see #objectFieldOffset(Field) 1085 */ 1086 public long objectFieldOffset(Class<?> c, String name) { 1087 if (c == null || name == null) { 1088 throw new NullPointerException(); 1089 } 1090 1091 return objectFieldOffset1(c, name); 1092 } 1093 1094 /** 1095 * Reports the location of a given static field, in conjunction with {@link 1096 * #staticFieldBase}. 1097 * <p>Do not expect to perform any sort of arithmetic on this offset; 1098 * it is just a cookie which is passed to the unsafe heap memory accessors. 1099 * 1100 * <p>Any given field will always have the same offset, and no two distinct 1101 * fields of the same class will ever have the same offset. 1102 * 1103 * <p>As of 1.4.1, offsets for fields are represented as long values, 1104 * although the Sun JVM does not use the most significant 32 bits. 1105 * It is hard to imagine a JVM technology which needs more than 1106 * a few bits to encode an offset within a non-array object, 1107 * However, for consistency with other methods in this class, 1108 * this method reports its result as a long value. 1109 * @see #getInt(Object, long) 1110 */ 1111 public long staticFieldOffset(Field f) { 1112 if (f == null) { 1113 throw new NullPointerException(); 1114 } 1115 1116 return staticFieldOffset0(f); 1117 } 1118 1119 /** 1120 * Reports the location of a given static field, in conjunction with {@link 1121 * #staticFieldOffset}. 1122 * <p>Fetch the base "Object", if any, with which static fields of the 1123 * given class can be accessed via methods like {@link #getInt(Object, 1124 * long)}. This value may be null. This value may refer to an object 1125 * which is a "cookie", not guaranteed to be a real Object, and it should 1126 * not be used in any way except as argument to the get and put routines in 1127 * this class. 1128 */ 1129 public Object staticFieldBase(Field f) { 1130 if (f == null) { 1131 throw new NullPointerException(); 1132 } 1133 1134 return staticFieldBase0(f); 1135 } 1136 1137 /** 1138 * Detects if the given class may need to be initialized. This is often 1139 * needed in conjunction with obtaining the static field base of a 1140 * class. 1141 * @return false only if a call to {@code ensureClassInitialized} would have no effect 1142 */ 1143 public boolean shouldBeInitialized(Class<?> c) { 1144 if (c == null) { 1145 throw new NullPointerException(); 1146 } 1147 1148 return shouldBeInitialized0(c); 1149 } 1150 1151 /** 1152 * Ensures the given class has been initialized (see JVMS-5.5 for details). 1153 * This is often needed in conjunction with obtaining the static field base 1154 * of a class. 1155 * 1156 * The call returns when either class {@code c} is fully initialized or 1157 * class {@code c} is being initialized and the call is performed from 1158 * the initializing thread. In the latter case a subsequent call to 1159 * {@link #shouldBeInitialized} will return {@code true}. 1160 */ 1161 public void ensureClassInitialized(Class<?> c) { 1162 if (c == null) { 1163 throw new NullPointerException(); 1164 } 1165 1166 ensureClassInitialized0(c); 1167 } 1168 1169 /** 1170 * Reports the offset of the first element in the storage allocation of a 1171 * given array class. If {@link #arrayIndexScale} returns a non-zero value 1172 * for the same class, you may use that scale factor, together with this 1173 * base offset, to form new offsets to access elements of arrays of the 1174 * given class. 1175 * 1176 * @see #getInt(Object, long) 1177 * @see #putInt(Object, long, int) 1178 */ 1179 public int arrayBaseOffset(Class<?> arrayClass) { 1180 if (arrayClass == null) { 1181 throw new NullPointerException(); 1182 } 1183 1184 return arrayBaseOffset0(arrayClass); 1185 } 1186 1187 1188 /** The value of {@code arrayBaseOffset(boolean[].class)} */ 1189 public static final int ARRAY_BOOLEAN_BASE_OFFSET 1190 = theUnsafe.arrayBaseOffset(boolean[].class); 1191 1192 /** The value of {@code arrayBaseOffset(byte[].class)} */ 1193 public static final int ARRAY_BYTE_BASE_OFFSET 1194 = theUnsafe.arrayBaseOffset(byte[].class); 1195 1196 /** The value of {@code arrayBaseOffset(short[].class)} */ 1197 public static final int ARRAY_SHORT_BASE_OFFSET 1198 = theUnsafe.arrayBaseOffset(short[].class); 1199 1200 /** The value of {@code arrayBaseOffset(char[].class)} */ 1201 public static final int ARRAY_CHAR_BASE_OFFSET 1202 = theUnsafe.arrayBaseOffset(char[].class); 1203 1204 /** The value of {@code arrayBaseOffset(int[].class)} */ 1205 public static final int ARRAY_INT_BASE_OFFSET 1206 = theUnsafe.arrayBaseOffset(int[].class); 1207 1208 /** The value of {@code arrayBaseOffset(long[].class)} */ 1209 public static final int ARRAY_LONG_BASE_OFFSET 1210 = theUnsafe.arrayBaseOffset(long[].class); 1211 1212 /** The value of {@code arrayBaseOffset(float[].class)} */ 1213 public static final int ARRAY_FLOAT_BASE_OFFSET 1214 = theUnsafe.arrayBaseOffset(float[].class); 1215 1216 /** The value of {@code arrayBaseOffset(double[].class)} */ 1217 public static final int ARRAY_DOUBLE_BASE_OFFSET 1218 = theUnsafe.arrayBaseOffset(double[].class); 1219 1220 /** The value of {@code arrayBaseOffset(Object[].class)} */ 1221 public static final int ARRAY_OBJECT_BASE_OFFSET 1222 = theUnsafe.arrayBaseOffset(Object[].class); 1223 1224 /** 1225 * Reports the scale factor for addressing elements in the storage 1226 * allocation of a given array class. However, arrays of "narrow" types 1227 * will generally not work properly with accessors like {@link 1228 * #getByte(Object, long)}, so the scale factor for such classes is reported 1229 * as zero. 1230 * 1231 * @see #arrayBaseOffset 1232 * @see #getInt(Object, long) 1233 * @see #putInt(Object, long, int) 1234 */ 1235 public int arrayIndexScale(Class<?> arrayClass) { 1236 if (arrayClass == null) { 1237 throw new NullPointerException(); 1238 } 1239 1240 return arrayIndexScale0(arrayClass); 1241 } 1242 1243 1244 /** The value of {@code arrayIndexScale(boolean[].class)} */ 1245 public static final int ARRAY_BOOLEAN_INDEX_SCALE 1246 = theUnsafe.arrayIndexScale(boolean[].class); 1247 1248 /** The value of {@code arrayIndexScale(byte[].class)} */ 1249 public static final int ARRAY_BYTE_INDEX_SCALE 1250 = theUnsafe.arrayIndexScale(byte[].class); 1251 1252 /** The value of {@code arrayIndexScale(short[].class)} */ 1253 public static final int ARRAY_SHORT_INDEX_SCALE 1254 = theUnsafe.arrayIndexScale(short[].class); 1255 1256 /** The value of {@code arrayIndexScale(char[].class)} */ 1257 public static final int ARRAY_CHAR_INDEX_SCALE 1258 = theUnsafe.arrayIndexScale(char[].class); 1259 1260 /** The value of {@code arrayIndexScale(int[].class)} */ 1261 public static final int ARRAY_INT_INDEX_SCALE 1262 = theUnsafe.arrayIndexScale(int[].class); 1263 1264 /** The value of {@code arrayIndexScale(long[].class)} */ 1265 public static final int ARRAY_LONG_INDEX_SCALE 1266 = theUnsafe.arrayIndexScale(long[].class); 1267 1268 /** The value of {@code arrayIndexScale(float[].class)} */ 1269 public static final int ARRAY_FLOAT_INDEX_SCALE 1270 = theUnsafe.arrayIndexScale(float[].class); 1271 1272 /** The value of {@code arrayIndexScale(double[].class)} */ 1273 public static final int ARRAY_DOUBLE_INDEX_SCALE 1274 = theUnsafe.arrayIndexScale(double[].class); 1275 1276 /** The value of {@code arrayIndexScale(Object[].class)} */ 1277 public static final int ARRAY_OBJECT_INDEX_SCALE 1278 = theUnsafe.arrayIndexScale(Object[].class); 1279 1280 /** 1281 * Reports the size in bytes of a native pointer, as stored via {@link 1282 * #putAddress}. This value will be either 4 or 8. Note that the sizes of 1283 * other primitive types (as stored in native memory blocks) is determined 1284 * fully by their information content. 1285 */ 1286 public int addressSize() { 1287 return ADDRESS_SIZE; 1288 } 1289 1290 /** The value of {@code addressSize()} */ 1291 public static final int ADDRESS_SIZE = ADDRESS_SIZE0; 1292 1293 /** 1294 * Reports the size in bytes of a native memory page (whatever that is). 1295 * This value will always be a power of two. 1296 */ 1297 public int pageSize() { return PAGE_SIZE; } 1298 1299 /** 1300 * Reports the size in bytes of a data cache line written back by 1301 * the hardware cache line flush operation available to the JVM or 1302 * 0 if data cache line flushing is not enabled. 1303 */ 1304 public int dataCacheLineFlushSize() { return DATA_CACHE_LINE_FLUSH_SIZE; } 1305 1306 /** 1307 * Rounds down address to a data cache line boundary as 1308 * determined by {@link #dataCacheLineFlushSize} 1309 * @return the rounded down address 1310 */ 1311 public long dataCacheLineAlignDown(long address) { 1312 return (address & ~(DATA_CACHE_LINE_FLUSH_SIZE - 1)); 1313 } 1314 1315 /** 1316 * Returns true if data cache line writeback 1317 */ 1318 public static boolean isWritebackEnabled() { return DATA_CACHE_LINE_FLUSH_SIZE != 0; } 1319 1320 //--- random trusted operations from JNI: 1321 1322 /** 1323 * Tells the VM to define a class, without security checks. By default, the 1324 * class loader and protection domain come from the caller's class. 1325 */ 1326 public Class<?> defineClass(String name, byte[] b, int off, int len, 1327 ClassLoader loader, 1328 ProtectionDomain protectionDomain) { 1329 if (b == null) { 1330 throw new NullPointerException(); 1331 } 1332 if (len < 0) { 1333 throw new ArrayIndexOutOfBoundsException(); 1334 } 1335 1336 return defineClass0(name, b, off, len, loader, protectionDomain); 1337 } 1338 1339 public native Class<?> defineClass0(String name, byte[] b, int off, int len, 1340 ClassLoader loader, 1341 ProtectionDomain protectionDomain); 1342 1343 /** 1344 * Allocates an instance but does not run any constructor. 1345 * Initializes the class if it has not yet been. 1346 */ 1347 @IntrinsicCandidate 1348 public native Object allocateInstance(Class<?> cls) 1349 throws InstantiationException; 1350 1351 /** 1352 * Allocates an array of a given type, but does not do zeroing. 1353 * <p> 1354 * This method should only be used in the very rare cases where a high-performance code 1355 * overwrites the destination array completely, and compilers cannot assist in zeroing elimination. 1356 * In an overwhelming majority of cases, a normal Java allocation should be used instead. 1357 * <p> 1358 * Users of this method are <b>required</b> to overwrite the initial (garbage) array contents 1359 * before allowing untrusted code, or code in other threads, to observe the reference 1360 * to the newly allocated array. In addition, the publication of the array reference must be 1361 * safe according to the Java Memory Model requirements. 1362 * <p> 1363 * The safest approach to deal with an uninitialized array is to keep the reference to it in local 1364 * variable at least until the initialization is complete, and then publish it <b>once</b>, either 1365 * by writing it to a <em>volatile</em> field, or storing it into a <em>final</em> field in constructor, 1366 * or issuing a {@link #storeFence} before publishing the reference. 1367 * <p> 1368 * @implnote This method can only allocate primitive arrays, to avoid garbage reference 1369 * elements that could break heap integrity. 1370 * 1371 * @param componentType array component type to allocate 1372 * @param length array size to allocate 1373 * @throws IllegalArgumentException if component type is null, or not a primitive class; 1374 * or the length is negative 1375 */ 1376 public Object allocateUninitializedArray(Class<?> componentType, int length) { 1377 if (componentType == null) { 1378 throw new IllegalArgumentException("Component type is null"); 1379 } 1380 if (!componentType.isPrimitive()) { 1381 throw new IllegalArgumentException("Component type is not primitive"); 1382 } 1383 if (length < 0) { 1384 throw new IllegalArgumentException("Negative length"); 1385 } 1386 return allocateUninitializedArray0(componentType, length); 1387 } 1388 1389 @IntrinsicCandidate 1390 private Object allocateUninitializedArray0(Class<?> componentType, int length) { 1391 // These fallbacks provide zeroed arrays, but intrinsic is not required to 1392 // return the zeroed arrays. 1393 if (componentType == byte.class) return new byte[length]; 1394 if (componentType == boolean.class) return new boolean[length]; 1395 if (componentType == short.class) return new short[length]; 1396 if (componentType == char.class) return new char[length]; 1397 if (componentType == int.class) return new int[length]; 1398 if (componentType == float.class) return new float[length]; 1399 if (componentType == long.class) return new long[length]; 1400 if (componentType == double.class) return new double[length]; 1401 return null; 1402 } 1403 1404 /** Throws the exception without telling the verifier. */ 1405 public native void throwException(Throwable ee); 1406 1407 /** 1408 * Atomically updates Java variable to {@code x} if it is currently 1409 * holding {@code expected}. 1410 * 1411 * <p>This operation has memory semantics of a {@code volatile} read 1412 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1413 * 1414 * @return {@code true} if successful 1415 */ 1416 @IntrinsicCandidate 1417 public final native boolean compareAndSetReference(Object o, long offset, 1418 Object expected, 1419 Object x); 1420 1421 @IntrinsicCandidate 1422 public final native Object compareAndExchangeReference(Object o, long offset, 1423 Object expected, 1424 Object x); 1425 1426 @IntrinsicCandidate 1427 public final Object compareAndExchangeReferenceAcquire(Object o, long offset, 1428 Object expected, 1429 Object x) { 1430 return compareAndExchangeReference(o, offset, expected, x); 1431 } 1432 1433 @IntrinsicCandidate 1434 public final Object compareAndExchangeReferenceRelease(Object o, long offset, 1435 Object expected, 1436 Object x) { 1437 return compareAndExchangeReference(o, offset, expected, x); 1438 } 1439 1440 @IntrinsicCandidate 1441 public final boolean weakCompareAndSetReferencePlain(Object o, long offset, 1442 Object expected, 1443 Object x) { 1444 return compareAndSetReference(o, offset, expected, x); 1445 } 1446 1447 @IntrinsicCandidate 1448 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset, 1449 Object expected, 1450 Object x) { 1451 return compareAndSetReference(o, offset, expected, x); 1452 } 1453 1454 @IntrinsicCandidate 1455 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset, 1456 Object expected, 1457 Object x) { 1458 return compareAndSetReference(o, offset, expected, x); 1459 } 1460 1461 @IntrinsicCandidate 1462 public final boolean weakCompareAndSetReference(Object o, long offset, 1463 Object expected, 1464 Object x) { 1465 return compareAndSetReference(o, offset, expected, x); 1466 } 1467 1468 /** 1469 * Atomically updates Java variable to {@code x} if it is currently 1470 * holding {@code expected}. 1471 * 1472 * <p>This operation has memory semantics of a {@code volatile} read 1473 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1474 * 1475 * @return {@code true} if successful 1476 */ 1477 @IntrinsicCandidate 1478 public final native boolean compareAndSetInt(Object o, long offset, 1479 int expected, 1480 int x); 1481 1482 @IntrinsicCandidate 1483 public final native int compareAndExchangeInt(Object o, long offset, 1484 int expected, 1485 int x); 1486 1487 @IntrinsicCandidate 1488 public final int compareAndExchangeIntAcquire(Object o, long offset, 1489 int expected, 1490 int x) { 1491 return compareAndExchangeInt(o, offset, expected, x); 1492 } 1493 1494 @IntrinsicCandidate 1495 public final int compareAndExchangeIntRelease(Object o, long offset, 1496 int expected, 1497 int x) { 1498 return compareAndExchangeInt(o, offset, expected, x); 1499 } 1500 1501 @IntrinsicCandidate 1502 public final boolean weakCompareAndSetIntPlain(Object o, long offset, 1503 int expected, 1504 int x) { 1505 return compareAndSetInt(o, offset, expected, x); 1506 } 1507 1508 @IntrinsicCandidate 1509 public final boolean weakCompareAndSetIntAcquire(Object o, long offset, 1510 int expected, 1511 int x) { 1512 return compareAndSetInt(o, offset, expected, x); 1513 } 1514 1515 @IntrinsicCandidate 1516 public final boolean weakCompareAndSetIntRelease(Object o, long offset, 1517 int expected, 1518 int x) { 1519 return compareAndSetInt(o, offset, expected, x); 1520 } 1521 1522 @IntrinsicCandidate 1523 public final boolean weakCompareAndSetInt(Object o, long offset, 1524 int expected, 1525 int x) { 1526 return compareAndSetInt(o, offset, expected, x); 1527 } 1528 1529 @IntrinsicCandidate 1530 public final byte compareAndExchangeByte(Object o, long offset, 1531 byte expected, 1532 byte x) { 1533 long wordOffset = offset & ~3; 1534 int shift = (int) (offset & 3) << 3; 1535 if (BIG_ENDIAN) { 1536 shift = 24 - shift; 1537 } 1538 int mask = 0xFF << shift; 1539 int maskedExpected = (expected & 0xFF) << shift; 1540 int maskedX = (x & 0xFF) << shift; 1541 int fullWord; 1542 do { 1543 fullWord = getIntVolatile(o, wordOffset); 1544 if ((fullWord & mask) != maskedExpected) 1545 return (byte) ((fullWord & mask) >> shift); 1546 } while (!weakCompareAndSetInt(o, wordOffset, 1547 fullWord, (fullWord & ~mask) | maskedX)); 1548 return expected; 1549 } 1550 1551 @IntrinsicCandidate 1552 public final boolean compareAndSetByte(Object o, long offset, 1553 byte expected, 1554 byte x) { 1555 return compareAndExchangeByte(o, offset, expected, x) == expected; 1556 } 1557 1558 @IntrinsicCandidate 1559 public final boolean weakCompareAndSetByte(Object o, long offset, 1560 byte expected, 1561 byte x) { 1562 return compareAndSetByte(o, offset, expected, x); 1563 } 1564 1565 @IntrinsicCandidate 1566 public final boolean weakCompareAndSetByteAcquire(Object o, long offset, 1567 byte expected, 1568 byte x) { 1569 return weakCompareAndSetByte(o, offset, expected, x); 1570 } 1571 1572 @IntrinsicCandidate 1573 public final boolean weakCompareAndSetByteRelease(Object o, long offset, 1574 byte expected, 1575 byte x) { 1576 return weakCompareAndSetByte(o, offset, expected, x); 1577 } 1578 1579 @IntrinsicCandidate 1580 public final boolean weakCompareAndSetBytePlain(Object o, long offset, 1581 byte expected, 1582 byte x) { 1583 return weakCompareAndSetByte(o, offset, expected, x); 1584 } 1585 1586 @IntrinsicCandidate 1587 public final byte compareAndExchangeByteAcquire(Object o, long offset, 1588 byte expected, 1589 byte x) { 1590 return compareAndExchangeByte(o, offset, expected, x); 1591 } 1592 1593 @IntrinsicCandidate 1594 public final byte compareAndExchangeByteRelease(Object o, long offset, 1595 byte expected, 1596 byte x) { 1597 return compareAndExchangeByte(o, offset, expected, x); 1598 } 1599 1600 @IntrinsicCandidate 1601 public final short compareAndExchangeShort(Object o, long offset, 1602 short expected, 1603 short x) { 1604 if ((offset & 3) == 3) { 1605 throw new IllegalArgumentException("Update spans the word, not supported"); 1606 } 1607 long wordOffset = offset & ~3; 1608 int shift = (int) (offset & 3) << 3; 1609 if (BIG_ENDIAN) { 1610 shift = 16 - shift; 1611 } 1612 int mask = 0xFFFF << shift; 1613 int maskedExpected = (expected & 0xFFFF) << shift; 1614 int maskedX = (x & 0xFFFF) << shift; 1615 int fullWord; 1616 do { 1617 fullWord = getIntVolatile(o, wordOffset); 1618 if ((fullWord & mask) != maskedExpected) { 1619 return (short) ((fullWord & mask) >> shift); 1620 } 1621 } while (!weakCompareAndSetInt(o, wordOffset, 1622 fullWord, (fullWord & ~mask) | maskedX)); 1623 return expected; 1624 } 1625 1626 @IntrinsicCandidate 1627 public final boolean compareAndSetShort(Object o, long offset, 1628 short expected, 1629 short x) { 1630 return compareAndExchangeShort(o, offset, expected, x) == expected; 1631 } 1632 1633 @IntrinsicCandidate 1634 public final boolean weakCompareAndSetShort(Object o, long offset, 1635 short expected, 1636 short x) { 1637 return compareAndSetShort(o, offset, expected, x); 1638 } 1639 1640 @IntrinsicCandidate 1641 public final boolean weakCompareAndSetShortAcquire(Object o, long offset, 1642 short expected, 1643 short x) { 1644 return weakCompareAndSetShort(o, offset, expected, x); 1645 } 1646 1647 @IntrinsicCandidate 1648 public final boolean weakCompareAndSetShortRelease(Object o, long offset, 1649 short expected, 1650 short x) { 1651 return weakCompareAndSetShort(o, offset, expected, x); 1652 } 1653 1654 @IntrinsicCandidate 1655 public final boolean weakCompareAndSetShortPlain(Object o, long offset, 1656 short expected, 1657 short x) { 1658 return weakCompareAndSetShort(o, offset, expected, x); 1659 } 1660 1661 1662 @IntrinsicCandidate 1663 public final short compareAndExchangeShortAcquire(Object o, long offset, 1664 short expected, 1665 short x) { 1666 return compareAndExchangeShort(o, offset, expected, x); 1667 } 1668 1669 @IntrinsicCandidate 1670 public final short compareAndExchangeShortRelease(Object o, long offset, 1671 short expected, 1672 short x) { 1673 return compareAndExchangeShort(o, offset, expected, x); 1674 } 1675 1676 @ForceInline 1677 private char s2c(short s) { 1678 return (char) s; 1679 } 1680 1681 @ForceInline 1682 private short c2s(char s) { 1683 return (short) s; 1684 } 1685 1686 @ForceInline 1687 public final boolean compareAndSetChar(Object o, long offset, 1688 char expected, 1689 char x) { 1690 return compareAndSetShort(o, offset, c2s(expected), c2s(x)); 1691 } 1692 1693 @ForceInline 1694 public final char compareAndExchangeChar(Object o, long offset, 1695 char expected, 1696 char x) { 1697 return s2c(compareAndExchangeShort(o, offset, c2s(expected), c2s(x))); 1698 } 1699 1700 @ForceInline 1701 public final char compareAndExchangeCharAcquire(Object o, long offset, 1702 char expected, 1703 char x) { 1704 return s2c(compareAndExchangeShortAcquire(o, offset, c2s(expected), c2s(x))); 1705 } 1706 1707 @ForceInline 1708 public final char compareAndExchangeCharRelease(Object o, long offset, 1709 char expected, 1710 char x) { 1711 return s2c(compareAndExchangeShortRelease(o, offset, c2s(expected), c2s(x))); 1712 } 1713 1714 @ForceInline 1715 public final boolean weakCompareAndSetChar(Object o, long offset, 1716 char expected, 1717 char x) { 1718 return weakCompareAndSetShort(o, offset, c2s(expected), c2s(x)); 1719 } 1720 1721 @ForceInline 1722 public final boolean weakCompareAndSetCharAcquire(Object o, long offset, 1723 char expected, 1724 char x) { 1725 return weakCompareAndSetShortAcquire(o, offset, c2s(expected), c2s(x)); 1726 } 1727 1728 @ForceInline 1729 public final boolean weakCompareAndSetCharRelease(Object o, long offset, 1730 char expected, 1731 char x) { 1732 return weakCompareAndSetShortRelease(o, offset, c2s(expected), c2s(x)); 1733 } 1734 1735 @ForceInline 1736 public final boolean weakCompareAndSetCharPlain(Object o, long offset, 1737 char expected, 1738 char x) { 1739 return weakCompareAndSetShortPlain(o, offset, c2s(expected), c2s(x)); 1740 } 1741 1742 /** 1743 * The JVM converts integral values to boolean values using two 1744 * different conventions, byte testing against zero and truncation 1745 * to least-significant bit. 1746 * 1747 * <p>The JNI documents specify that, at least for returning 1748 * values from native methods, a Java boolean value is converted 1749 * to the value-set 0..1 by first truncating to a byte (0..255 or 1750 * maybe -128..127) and then testing against zero. Thus, Java 1751 * booleans in non-Java data structures are by convention 1752 * represented as 8-bit containers containing either zero (for 1753 * false) or any non-zero value (for true). 1754 * 1755 * <p>Java booleans in the heap are also stored in bytes, but are 1756 * strongly normalized to the value-set 0..1 (i.e., they are 1757 * truncated to the least-significant bit). 1758 * 1759 * <p>The main reason for having different conventions for 1760 * conversion is performance: Truncation to the least-significant 1761 * bit can be usually implemented with fewer (machine) 1762 * instructions than byte testing against zero. 1763 * 1764 * <p>A number of Unsafe methods load boolean values from the heap 1765 * as bytes. Unsafe converts those values according to the JNI 1766 * rules (i.e, using the "testing against zero" convention). The 1767 * method {@code byte2bool} implements that conversion. 1768 * 1769 * @param b the byte to be converted to boolean 1770 * @return the result of the conversion 1771 */ 1772 @ForceInline 1773 private boolean byte2bool(byte b) { 1774 return b != 0; 1775 } 1776 1777 /** 1778 * Convert a boolean value to a byte. The return value is strongly 1779 * normalized to the value-set 0..1 (i.e., the value is truncated 1780 * to the least-significant bit). See {@link #byte2bool(byte)} for 1781 * more details on conversion conventions. 1782 * 1783 * @param b the boolean to be converted to byte (and then normalized) 1784 * @return the result of the conversion 1785 */ 1786 @ForceInline 1787 private byte bool2byte(boolean b) { 1788 return b ? (byte)1 : (byte)0; 1789 } 1790 1791 @ForceInline 1792 public final boolean compareAndSetBoolean(Object o, long offset, 1793 boolean expected, 1794 boolean x) { 1795 return compareAndSetByte(o, offset, bool2byte(expected), bool2byte(x)); 1796 } 1797 1798 @ForceInline 1799 public final boolean compareAndExchangeBoolean(Object o, long offset, 1800 boolean expected, 1801 boolean x) { 1802 return byte2bool(compareAndExchangeByte(o, offset, bool2byte(expected), bool2byte(x))); 1803 } 1804 1805 @ForceInline 1806 public final boolean compareAndExchangeBooleanAcquire(Object o, long offset, 1807 boolean expected, 1808 boolean x) { 1809 return byte2bool(compareAndExchangeByteAcquire(o, offset, bool2byte(expected), bool2byte(x))); 1810 } 1811 1812 @ForceInline 1813 public final boolean compareAndExchangeBooleanRelease(Object o, long offset, 1814 boolean expected, 1815 boolean x) { 1816 return byte2bool(compareAndExchangeByteRelease(o, offset, bool2byte(expected), bool2byte(x))); 1817 } 1818 1819 @ForceInline 1820 public final boolean weakCompareAndSetBoolean(Object o, long offset, 1821 boolean expected, 1822 boolean x) { 1823 return weakCompareAndSetByte(o, offset, bool2byte(expected), bool2byte(x)); 1824 } 1825 1826 @ForceInline 1827 public final boolean weakCompareAndSetBooleanAcquire(Object o, long offset, 1828 boolean expected, 1829 boolean x) { 1830 return weakCompareAndSetByteAcquire(o, offset, bool2byte(expected), bool2byte(x)); 1831 } 1832 1833 @ForceInline 1834 public final boolean weakCompareAndSetBooleanRelease(Object o, long offset, 1835 boolean expected, 1836 boolean x) { 1837 return weakCompareAndSetByteRelease(o, offset, bool2byte(expected), bool2byte(x)); 1838 } 1839 1840 @ForceInline 1841 public final boolean weakCompareAndSetBooleanPlain(Object o, long offset, 1842 boolean expected, 1843 boolean x) { 1844 return weakCompareAndSetBytePlain(o, offset, bool2byte(expected), bool2byte(x)); 1845 } 1846 1847 /** 1848 * Atomically updates Java variable to {@code x} if it is currently 1849 * holding {@code expected}. 1850 * 1851 * <p>This operation has memory semantics of a {@code volatile} read 1852 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1853 * 1854 * @return {@code true} if successful 1855 */ 1856 @ForceInline 1857 public final boolean compareAndSetFloat(Object o, long offset, 1858 float expected, 1859 float x) { 1860 return compareAndSetInt(o, offset, 1861 Float.floatToRawIntBits(expected), 1862 Float.floatToRawIntBits(x)); 1863 } 1864 1865 @ForceInline 1866 public final float compareAndExchangeFloat(Object o, long offset, 1867 float expected, 1868 float x) { 1869 int w = compareAndExchangeInt(o, offset, 1870 Float.floatToRawIntBits(expected), 1871 Float.floatToRawIntBits(x)); 1872 return Float.intBitsToFloat(w); 1873 } 1874 1875 @ForceInline 1876 public final float compareAndExchangeFloatAcquire(Object o, long offset, 1877 float expected, 1878 float x) { 1879 int w = compareAndExchangeIntAcquire(o, offset, 1880 Float.floatToRawIntBits(expected), 1881 Float.floatToRawIntBits(x)); 1882 return Float.intBitsToFloat(w); 1883 } 1884 1885 @ForceInline 1886 public final float compareAndExchangeFloatRelease(Object o, long offset, 1887 float expected, 1888 float x) { 1889 int w = compareAndExchangeIntRelease(o, offset, 1890 Float.floatToRawIntBits(expected), 1891 Float.floatToRawIntBits(x)); 1892 return Float.intBitsToFloat(w); 1893 } 1894 1895 @ForceInline 1896 public final boolean weakCompareAndSetFloatPlain(Object o, long offset, 1897 float expected, 1898 float x) { 1899 return weakCompareAndSetIntPlain(o, offset, 1900 Float.floatToRawIntBits(expected), 1901 Float.floatToRawIntBits(x)); 1902 } 1903 1904 @ForceInline 1905 public final boolean weakCompareAndSetFloatAcquire(Object o, long offset, 1906 float expected, 1907 float x) { 1908 return weakCompareAndSetIntAcquire(o, offset, 1909 Float.floatToRawIntBits(expected), 1910 Float.floatToRawIntBits(x)); 1911 } 1912 1913 @ForceInline 1914 public final boolean weakCompareAndSetFloatRelease(Object o, long offset, 1915 float expected, 1916 float x) { 1917 return weakCompareAndSetIntRelease(o, offset, 1918 Float.floatToRawIntBits(expected), 1919 Float.floatToRawIntBits(x)); 1920 } 1921 1922 @ForceInline 1923 public final boolean weakCompareAndSetFloat(Object o, long offset, 1924 float expected, 1925 float x) { 1926 return weakCompareAndSetInt(o, offset, 1927 Float.floatToRawIntBits(expected), 1928 Float.floatToRawIntBits(x)); 1929 } 1930 1931 /** 1932 * Atomically updates Java variable to {@code x} if it is currently 1933 * holding {@code expected}. 1934 * 1935 * <p>This operation has memory semantics of a {@code volatile} read 1936 * and write. Corresponds to C11 atomic_compare_exchange_strong. 1937 * 1938 * @return {@code true} if successful 1939 */ 1940 @ForceInline 1941 public final boolean compareAndSetDouble(Object o, long offset, 1942 double expected, 1943 double x) { 1944 return compareAndSetLong(o, offset, 1945 Double.doubleToRawLongBits(expected), 1946 Double.doubleToRawLongBits(x)); 1947 } 1948 1949 @ForceInline 1950 public final double compareAndExchangeDouble(Object o, long offset, 1951 double expected, 1952 double x) { 1953 long w = compareAndExchangeLong(o, offset, 1954 Double.doubleToRawLongBits(expected), 1955 Double.doubleToRawLongBits(x)); 1956 return Double.longBitsToDouble(w); 1957 } 1958 1959 @ForceInline 1960 public final double compareAndExchangeDoubleAcquire(Object o, long offset, 1961 double expected, 1962 double x) { 1963 long w = compareAndExchangeLongAcquire(o, offset, 1964 Double.doubleToRawLongBits(expected), 1965 Double.doubleToRawLongBits(x)); 1966 return Double.longBitsToDouble(w); 1967 } 1968 1969 @ForceInline 1970 public final double compareAndExchangeDoubleRelease(Object o, long offset, 1971 double expected, 1972 double x) { 1973 long w = compareAndExchangeLongRelease(o, offset, 1974 Double.doubleToRawLongBits(expected), 1975 Double.doubleToRawLongBits(x)); 1976 return Double.longBitsToDouble(w); 1977 } 1978 1979 @ForceInline 1980 public final boolean weakCompareAndSetDoublePlain(Object o, long offset, 1981 double expected, 1982 double x) { 1983 return weakCompareAndSetLongPlain(o, offset, 1984 Double.doubleToRawLongBits(expected), 1985 Double.doubleToRawLongBits(x)); 1986 } 1987 1988 @ForceInline 1989 public final boolean weakCompareAndSetDoubleAcquire(Object o, long offset, 1990 double expected, 1991 double x) { 1992 return weakCompareAndSetLongAcquire(o, offset, 1993 Double.doubleToRawLongBits(expected), 1994 Double.doubleToRawLongBits(x)); 1995 } 1996 1997 @ForceInline 1998 public final boolean weakCompareAndSetDoubleRelease(Object o, long offset, 1999 double expected, 2000 double x) { 2001 return weakCompareAndSetLongRelease(o, offset, 2002 Double.doubleToRawLongBits(expected), 2003 Double.doubleToRawLongBits(x)); 2004 } 2005 2006 @ForceInline 2007 public final boolean weakCompareAndSetDouble(Object o, long offset, 2008 double expected, 2009 double x) { 2010 return weakCompareAndSetLong(o, offset, 2011 Double.doubleToRawLongBits(expected), 2012 Double.doubleToRawLongBits(x)); 2013 } 2014 2015 /** 2016 * Atomically updates Java variable to {@code x} if it is currently 2017 * holding {@code expected}. 2018 * 2019 * <p>This operation has memory semantics of a {@code volatile} read 2020 * and write. Corresponds to C11 atomic_compare_exchange_strong. 2021 * 2022 * @return {@code true} if successful 2023 */ 2024 @IntrinsicCandidate 2025 public final native boolean compareAndSetLong(Object o, long offset, 2026 long expected, 2027 long x); 2028 2029 @IntrinsicCandidate 2030 public final native long compareAndExchangeLong(Object o, long offset, 2031 long expected, 2032 long x); 2033 2034 @IntrinsicCandidate 2035 public final long compareAndExchangeLongAcquire(Object o, long offset, 2036 long expected, 2037 long x) { 2038 return compareAndExchangeLong(o, offset, expected, x); 2039 } 2040 2041 @IntrinsicCandidate 2042 public final long compareAndExchangeLongRelease(Object o, long offset, 2043 long expected, 2044 long x) { 2045 return compareAndExchangeLong(o, offset, expected, x); 2046 } 2047 2048 @IntrinsicCandidate 2049 public final boolean weakCompareAndSetLongPlain(Object o, long offset, 2050 long expected, 2051 long x) { 2052 return compareAndSetLong(o, offset, expected, x); 2053 } 2054 2055 @IntrinsicCandidate 2056 public final boolean weakCompareAndSetLongAcquire(Object o, long offset, 2057 long expected, 2058 long x) { 2059 return compareAndSetLong(o, offset, expected, x); 2060 } 2061 2062 @IntrinsicCandidate 2063 public final boolean weakCompareAndSetLongRelease(Object o, long offset, 2064 long expected, 2065 long x) { 2066 return compareAndSetLong(o, offset, expected, x); 2067 } 2068 2069 @IntrinsicCandidate 2070 public final boolean weakCompareAndSetLong(Object o, long offset, 2071 long expected, 2072 long x) { 2073 return compareAndSetLong(o, offset, expected, x); 2074 } 2075 2076 /** 2077 * Fetches a reference value from a given Java variable, with volatile 2078 * load semantics. Otherwise identical to {@link #getReference(Object, long)} 2079 */ 2080 @IntrinsicCandidate 2081 public native Object getReferenceVolatile(Object o, long offset); 2082 2083 /** 2084 * Stores a reference value into a given Java variable, with 2085 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)} 2086 */ 2087 @IntrinsicCandidate 2088 public native void putReferenceVolatile(Object o, long offset, Object x); 2089 2090 /** Volatile version of {@link #getInt(Object, long)} */ 2091 @IntrinsicCandidate 2092 public native int getIntVolatile(Object o, long offset); 2093 2094 /** Volatile version of {@link #putInt(Object, long, int)} */ 2095 @IntrinsicCandidate 2096 public native void putIntVolatile(Object o, long offset, int x); 2097 2098 /** Volatile version of {@link #getBoolean(Object, long)} */ 2099 @IntrinsicCandidate 2100 public native boolean getBooleanVolatile(Object o, long offset); 2101 2102 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */ 2103 @IntrinsicCandidate 2104 public native void putBooleanVolatile(Object o, long offset, boolean x); 2105 2106 /** Volatile version of {@link #getByte(Object, long)} */ 2107 @IntrinsicCandidate 2108 public native byte getByteVolatile(Object o, long offset); 2109 2110 /** Volatile version of {@link #putByte(Object, long, byte)} */ 2111 @IntrinsicCandidate 2112 public native void putByteVolatile(Object o, long offset, byte x); 2113 2114 /** Volatile version of {@link #getShort(Object, long)} */ 2115 @IntrinsicCandidate 2116 public native short getShortVolatile(Object o, long offset); 2117 2118 /** Volatile version of {@link #putShort(Object, long, short)} */ 2119 @IntrinsicCandidate 2120 public native void putShortVolatile(Object o, long offset, short x); 2121 2122 /** Volatile version of {@link #getChar(Object, long)} */ 2123 @IntrinsicCandidate 2124 public native char getCharVolatile(Object o, long offset); 2125 2126 /** Volatile version of {@link #putChar(Object, long, char)} */ 2127 @IntrinsicCandidate 2128 public native void putCharVolatile(Object o, long offset, char x); 2129 2130 /** Volatile version of {@link #getLong(Object, long)} */ 2131 @IntrinsicCandidate 2132 public native long getLongVolatile(Object o, long offset); 2133 2134 /** Volatile version of {@link #putLong(Object, long, long)} */ 2135 @IntrinsicCandidate 2136 public native void putLongVolatile(Object o, long offset, long x); 2137 2138 /** Volatile version of {@link #getFloat(Object, long)} */ 2139 @IntrinsicCandidate 2140 public native float getFloatVolatile(Object o, long offset); 2141 2142 /** Volatile version of {@link #putFloat(Object, long, float)} */ 2143 @IntrinsicCandidate 2144 public native void putFloatVolatile(Object o, long offset, float x); 2145 2146 /** Volatile version of {@link #getDouble(Object, long)} */ 2147 @IntrinsicCandidate 2148 public native double getDoubleVolatile(Object o, long offset); 2149 2150 /** Volatile version of {@link #putDouble(Object, long, double)} */ 2151 @IntrinsicCandidate 2152 public native void putDoubleVolatile(Object o, long offset, double x); 2153 2154 2155 2156 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */ 2157 @IntrinsicCandidate 2158 public final Object getReferenceAcquire(Object o, long offset) { 2159 return getReferenceVolatile(o, offset); 2160 } 2161 2162 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */ 2163 @IntrinsicCandidate 2164 public final boolean getBooleanAcquire(Object o, long offset) { 2165 return getBooleanVolatile(o, offset); 2166 } 2167 2168 /** Acquire version of {@link #getByteVolatile(Object, long)} */ 2169 @IntrinsicCandidate 2170 public final byte getByteAcquire(Object o, long offset) { 2171 return getByteVolatile(o, offset); 2172 } 2173 2174 /** Acquire version of {@link #getShortVolatile(Object, long)} */ 2175 @IntrinsicCandidate 2176 public final short getShortAcquire(Object o, long offset) { 2177 return getShortVolatile(o, offset); 2178 } 2179 2180 /** Acquire version of {@link #getCharVolatile(Object, long)} */ 2181 @IntrinsicCandidate 2182 public final char getCharAcquire(Object o, long offset) { 2183 return getCharVolatile(o, offset); 2184 } 2185 2186 /** Acquire version of {@link #getIntVolatile(Object, long)} */ 2187 @IntrinsicCandidate 2188 public final int getIntAcquire(Object o, long offset) { 2189 return getIntVolatile(o, offset); 2190 } 2191 2192 /** Acquire version of {@link #getFloatVolatile(Object, long)} */ 2193 @IntrinsicCandidate 2194 public final float getFloatAcquire(Object o, long offset) { 2195 return getFloatVolatile(o, offset); 2196 } 2197 2198 /** Acquire version of {@link #getLongVolatile(Object, long)} */ 2199 @IntrinsicCandidate 2200 public final long getLongAcquire(Object o, long offset) { 2201 return getLongVolatile(o, offset); 2202 } 2203 2204 /** Acquire version of {@link #getDoubleVolatile(Object, long)} */ 2205 @IntrinsicCandidate 2206 public final double getDoubleAcquire(Object o, long offset) { 2207 return getDoubleVolatile(o, offset); 2208 } 2209 2210 /* 2211 * Versions of {@link #putReferenceVolatile(Object, long, Object)} 2212 * that do not guarantee immediate visibility of the store to 2213 * other threads. This method is generally only useful if the 2214 * underlying field is a Java volatile (or if an array cell, one 2215 * that is otherwise only accessed using volatile accesses). 2216 * 2217 * Corresponds to C11 atomic_store_explicit(..., memory_order_release). 2218 */ 2219 2220 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */ 2221 @IntrinsicCandidate 2222 public final void putReferenceRelease(Object o, long offset, Object x) { 2223 putReferenceVolatile(o, offset, x); 2224 } 2225 2226 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */ 2227 @IntrinsicCandidate 2228 public final void putBooleanRelease(Object o, long offset, boolean x) { 2229 putBooleanVolatile(o, offset, x); 2230 } 2231 2232 /** Release version of {@link #putByteVolatile(Object, long, byte)} */ 2233 @IntrinsicCandidate 2234 public final void putByteRelease(Object o, long offset, byte x) { 2235 putByteVolatile(o, offset, x); 2236 } 2237 2238 /** Release version of {@link #putShortVolatile(Object, long, short)} */ 2239 @IntrinsicCandidate 2240 public final void putShortRelease(Object o, long offset, short x) { 2241 putShortVolatile(o, offset, x); 2242 } 2243 2244 /** Release version of {@link #putCharVolatile(Object, long, char)} */ 2245 @IntrinsicCandidate 2246 public final void putCharRelease(Object o, long offset, char x) { 2247 putCharVolatile(o, offset, x); 2248 } 2249 2250 /** Release version of {@link #putIntVolatile(Object, long, int)} */ 2251 @IntrinsicCandidate 2252 public final void putIntRelease(Object o, long offset, int x) { 2253 putIntVolatile(o, offset, x); 2254 } 2255 2256 /** Release version of {@link #putFloatVolatile(Object, long, float)} */ 2257 @IntrinsicCandidate 2258 public final void putFloatRelease(Object o, long offset, float x) { 2259 putFloatVolatile(o, offset, x); 2260 } 2261 2262 /** Release version of {@link #putLongVolatile(Object, long, long)} */ 2263 @IntrinsicCandidate 2264 public final void putLongRelease(Object o, long offset, long x) { 2265 putLongVolatile(o, offset, x); 2266 } 2267 2268 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */ 2269 @IntrinsicCandidate 2270 public final void putDoubleRelease(Object o, long offset, double x) { 2271 putDoubleVolatile(o, offset, x); 2272 } 2273 2274 // ------------------------------ Opaque -------------------------------------- 2275 2276 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */ 2277 @IntrinsicCandidate 2278 public final Object getReferenceOpaque(Object o, long offset) { 2279 return getReferenceVolatile(o, offset); 2280 } 2281 2282 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */ 2283 @IntrinsicCandidate 2284 public final boolean getBooleanOpaque(Object o, long offset) { 2285 return getBooleanVolatile(o, offset); 2286 } 2287 2288 /** Opaque version of {@link #getByteVolatile(Object, long)} */ 2289 @IntrinsicCandidate 2290 public final byte getByteOpaque(Object o, long offset) { 2291 return getByteVolatile(o, offset); 2292 } 2293 2294 /** Opaque version of {@link #getShortVolatile(Object, long)} */ 2295 @IntrinsicCandidate 2296 public final short getShortOpaque(Object o, long offset) { 2297 return getShortVolatile(o, offset); 2298 } 2299 2300 /** Opaque version of {@link #getCharVolatile(Object, long)} */ 2301 @IntrinsicCandidate 2302 public final char getCharOpaque(Object o, long offset) { 2303 return getCharVolatile(o, offset); 2304 } 2305 2306 /** Opaque version of {@link #getIntVolatile(Object, long)} */ 2307 @IntrinsicCandidate 2308 public final int getIntOpaque(Object o, long offset) { 2309 return getIntVolatile(o, offset); 2310 } 2311 2312 /** Opaque version of {@link #getFloatVolatile(Object, long)} */ 2313 @IntrinsicCandidate 2314 public final float getFloatOpaque(Object o, long offset) { 2315 return getFloatVolatile(o, offset); 2316 } 2317 2318 /** Opaque version of {@link #getLongVolatile(Object, long)} */ 2319 @IntrinsicCandidate 2320 public final long getLongOpaque(Object o, long offset) { 2321 return getLongVolatile(o, offset); 2322 } 2323 2324 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */ 2325 @IntrinsicCandidate 2326 public final double getDoubleOpaque(Object o, long offset) { 2327 return getDoubleVolatile(o, offset); 2328 } 2329 2330 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */ 2331 @IntrinsicCandidate 2332 public final void putReferenceOpaque(Object o, long offset, Object x) { 2333 putReferenceVolatile(o, offset, x); 2334 } 2335 2336 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */ 2337 @IntrinsicCandidate 2338 public final void putBooleanOpaque(Object o, long offset, boolean x) { 2339 putBooleanVolatile(o, offset, x); 2340 } 2341 2342 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */ 2343 @IntrinsicCandidate 2344 public final void putByteOpaque(Object o, long offset, byte x) { 2345 putByteVolatile(o, offset, x); 2346 } 2347 2348 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */ 2349 @IntrinsicCandidate 2350 public final void putShortOpaque(Object o, long offset, short x) { 2351 putShortVolatile(o, offset, x); 2352 } 2353 2354 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */ 2355 @IntrinsicCandidate 2356 public final void putCharOpaque(Object o, long offset, char x) { 2357 putCharVolatile(o, offset, x); 2358 } 2359 2360 /** Opaque version of {@link #putIntVolatile(Object, long, int)} */ 2361 @IntrinsicCandidate 2362 public final void putIntOpaque(Object o, long offset, int x) { 2363 putIntVolatile(o, offset, x); 2364 } 2365 2366 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */ 2367 @IntrinsicCandidate 2368 public final void putFloatOpaque(Object o, long offset, float x) { 2369 putFloatVolatile(o, offset, x); 2370 } 2371 2372 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */ 2373 @IntrinsicCandidate 2374 public final void putLongOpaque(Object o, long offset, long x) { 2375 putLongVolatile(o, offset, x); 2376 } 2377 2378 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */ 2379 @IntrinsicCandidate 2380 public final void putDoubleOpaque(Object o, long offset, double x) { 2381 putDoubleVolatile(o, offset, x); 2382 } 2383 2384 /** 2385 * Unblocks the given thread blocked on {@code park}, or, if it is 2386 * not blocked, causes the subsequent call to {@code park} not to 2387 * block. Note: this operation is "unsafe" solely because the 2388 * caller must somehow ensure that the thread has not been 2389 * destroyed. Nothing special is usually required to ensure this 2390 * when called from Java (in which there will ordinarily be a live 2391 * reference to the thread) but this is not nearly-automatically 2392 * so when calling from native code. 2393 * 2394 * @param thread the thread to unpark. 2395 */ 2396 @IntrinsicCandidate 2397 public native void unpark(Object thread); 2398 2399 /** 2400 * Blocks current thread, returning when a balancing 2401 * {@code unpark} occurs, or a balancing {@code unpark} has 2402 * already occurred, or the thread is interrupted, or, if not 2403 * absolute and time is not zero, the given time nanoseconds have 2404 * elapsed, or if absolute, the given deadline in milliseconds 2405 * since Epoch has passed, or spuriously (i.e., returning for no 2406 * "reason"). Note: This operation is in the Unsafe class only 2407 * because {@code unpark} is, so it would be strange to place it 2408 * elsewhere. 2409 */ 2410 @IntrinsicCandidate 2411 public native void park(boolean isAbsolute, long time); 2412 2413 /** 2414 * Gets the load average in the system run queue assigned 2415 * to the available processors averaged over various periods of time. 2416 * This method retrieves the given {@code nelem} samples and 2417 * assigns to the elements of the given {@code loadavg} array. 2418 * The system imposes a maximum of 3 samples, representing 2419 * averages over the last 1, 5, and 15 minutes, respectively. 2420 * 2421 * @param loadavg an array of double of size nelems 2422 * @param nelems the number of samples to be retrieved and 2423 * must be 1 to 3. 2424 * 2425 * @return the number of samples actually retrieved; or -1 2426 * if the load average is unobtainable. 2427 */ 2428 public int getLoadAverage(double[] loadavg, int nelems) { 2429 if (nelems < 0 || nelems > 3 || nelems > loadavg.length) { 2430 throw new ArrayIndexOutOfBoundsException(); 2431 } 2432 2433 return getLoadAverage0(loadavg, nelems); 2434 } 2435 2436 // The following contain CAS-based Java implementations used on 2437 // platforms not supporting native instructions 2438 2439 /** 2440 * Atomically adds the given value to the current value of a field 2441 * or array element within the given object {@code o} 2442 * at the given {@code offset}. 2443 * 2444 * @param o object/array to update the field/element in 2445 * @param offset field/element offset 2446 * @param delta the value to add 2447 * @return the previous value 2448 * @since 1.8 2449 */ 2450 @IntrinsicCandidate 2451 public final int getAndAddInt(Object o, long offset, int delta) { 2452 int v; 2453 do { 2454 v = getIntVolatile(o, offset); 2455 } while (!weakCompareAndSetInt(o, offset, v, v + delta)); 2456 return v; 2457 } 2458 2459 @ForceInline 2460 public final int getAndAddIntRelease(Object o, long offset, int delta) { 2461 int v; 2462 do { 2463 v = getInt(o, offset); 2464 } while (!weakCompareAndSetIntRelease(o, offset, v, v + delta)); 2465 return v; 2466 } 2467 2468 @ForceInline 2469 public final int getAndAddIntAcquire(Object o, long offset, int delta) { 2470 int v; 2471 do { 2472 v = getIntAcquire(o, offset); 2473 } while (!weakCompareAndSetIntAcquire(o, offset, v, v + delta)); 2474 return v; 2475 } 2476 2477 /** 2478 * Atomically adds the given value to the current value of a field 2479 * or array element within the given object {@code o} 2480 * at the given {@code offset}. 2481 * 2482 * @param o object/array to update the field/element in 2483 * @param offset field/element offset 2484 * @param delta the value to add 2485 * @return the previous value 2486 * @since 1.8 2487 */ 2488 @IntrinsicCandidate 2489 public final long getAndAddLong(Object o, long offset, long delta) { 2490 long v; 2491 do { 2492 v = getLongVolatile(o, offset); 2493 } while (!weakCompareAndSetLong(o, offset, v, v + delta)); 2494 return v; 2495 } 2496 2497 @ForceInline 2498 public final long getAndAddLongRelease(Object o, long offset, long delta) { 2499 long v; 2500 do { 2501 v = getLong(o, offset); 2502 } while (!weakCompareAndSetLongRelease(o, offset, v, v + delta)); 2503 return v; 2504 } 2505 2506 @ForceInline 2507 public final long getAndAddLongAcquire(Object o, long offset, long delta) { 2508 long v; 2509 do { 2510 v = getLongAcquire(o, offset); 2511 } while (!weakCompareAndSetLongAcquire(o, offset, v, v + delta)); 2512 return v; 2513 } 2514 2515 @IntrinsicCandidate 2516 public final byte getAndAddByte(Object o, long offset, byte delta) { 2517 byte v; 2518 do { 2519 v = getByteVolatile(o, offset); 2520 } while (!weakCompareAndSetByte(o, offset, v, (byte) (v + delta))); 2521 return v; 2522 } 2523 2524 @ForceInline 2525 public final byte getAndAddByteRelease(Object o, long offset, byte delta) { 2526 byte v; 2527 do { 2528 v = getByte(o, offset); 2529 } while (!weakCompareAndSetByteRelease(o, offset, v, (byte) (v + delta))); 2530 return v; 2531 } 2532 2533 @ForceInline 2534 public final byte getAndAddByteAcquire(Object o, long offset, byte delta) { 2535 byte v; 2536 do { 2537 v = getByteAcquire(o, offset); 2538 } while (!weakCompareAndSetByteAcquire(o, offset, v, (byte) (v + delta))); 2539 return v; 2540 } 2541 2542 @IntrinsicCandidate 2543 public final short getAndAddShort(Object o, long offset, short delta) { 2544 short v; 2545 do { 2546 v = getShortVolatile(o, offset); 2547 } while (!weakCompareAndSetShort(o, offset, v, (short) (v + delta))); 2548 return v; 2549 } 2550 2551 @ForceInline 2552 public final short getAndAddShortRelease(Object o, long offset, short delta) { 2553 short v; 2554 do { 2555 v = getShort(o, offset); 2556 } while (!weakCompareAndSetShortRelease(o, offset, v, (short) (v + delta))); 2557 return v; 2558 } 2559 2560 @ForceInline 2561 public final short getAndAddShortAcquire(Object o, long offset, short delta) { 2562 short v; 2563 do { 2564 v = getShortAcquire(o, offset); 2565 } while (!weakCompareAndSetShortAcquire(o, offset, v, (short) (v + delta))); 2566 return v; 2567 } 2568 2569 @ForceInline 2570 public final char getAndAddChar(Object o, long offset, char delta) { 2571 return (char) getAndAddShort(o, offset, (short) delta); 2572 } 2573 2574 @ForceInline 2575 public final char getAndAddCharRelease(Object o, long offset, char delta) { 2576 return (char) getAndAddShortRelease(o, offset, (short) delta); 2577 } 2578 2579 @ForceInline 2580 public final char getAndAddCharAcquire(Object o, long offset, char delta) { 2581 return (char) getAndAddShortAcquire(o, offset, (short) delta); 2582 } 2583 2584 @ForceInline 2585 public final float getAndAddFloat(Object o, long offset, float delta) { 2586 int expectedBits; 2587 float v; 2588 do { 2589 // Load and CAS with the raw bits to avoid issues with NaNs and 2590 // possible bit conversion from signaling NaNs to quiet NaNs that 2591 // may result in the loop not terminating. 2592 expectedBits = getIntVolatile(o, offset); 2593 v = Float.intBitsToFloat(expectedBits); 2594 } while (!weakCompareAndSetInt(o, offset, 2595 expectedBits, Float.floatToRawIntBits(v + delta))); 2596 return v; 2597 } 2598 2599 @ForceInline 2600 public final float getAndAddFloatRelease(Object o, long offset, float delta) { 2601 int expectedBits; 2602 float v; 2603 do { 2604 // Load and CAS with the raw bits to avoid issues with NaNs and 2605 // possible bit conversion from signaling NaNs to quiet NaNs that 2606 // may result in the loop not terminating. 2607 expectedBits = getInt(o, offset); 2608 v = Float.intBitsToFloat(expectedBits); 2609 } while (!weakCompareAndSetIntRelease(o, offset, 2610 expectedBits, Float.floatToRawIntBits(v + delta))); 2611 return v; 2612 } 2613 2614 @ForceInline 2615 public final float getAndAddFloatAcquire(Object o, long offset, float delta) { 2616 int expectedBits; 2617 float v; 2618 do { 2619 // Load and CAS with the raw bits to avoid issues with NaNs and 2620 // possible bit conversion from signaling NaNs to quiet NaNs that 2621 // may result in the loop not terminating. 2622 expectedBits = getIntAcquire(o, offset); 2623 v = Float.intBitsToFloat(expectedBits); 2624 } while (!weakCompareAndSetIntAcquire(o, offset, 2625 expectedBits, Float.floatToRawIntBits(v + delta))); 2626 return v; 2627 } 2628 2629 @ForceInline 2630 public final double getAndAddDouble(Object o, long offset, double delta) { 2631 long expectedBits; 2632 double v; 2633 do { 2634 // Load and CAS with the raw bits to avoid issues with NaNs and 2635 // possible bit conversion from signaling NaNs to quiet NaNs that 2636 // may result in the loop not terminating. 2637 expectedBits = getLongVolatile(o, offset); 2638 v = Double.longBitsToDouble(expectedBits); 2639 } while (!weakCompareAndSetLong(o, offset, 2640 expectedBits, Double.doubleToRawLongBits(v + delta))); 2641 return v; 2642 } 2643 2644 @ForceInline 2645 public final double getAndAddDoubleRelease(Object o, long offset, double delta) { 2646 long expectedBits; 2647 double v; 2648 do { 2649 // Load and CAS with the raw bits to avoid issues with NaNs and 2650 // possible bit conversion from signaling NaNs to quiet NaNs that 2651 // may result in the loop not terminating. 2652 expectedBits = getLong(o, offset); 2653 v = Double.longBitsToDouble(expectedBits); 2654 } while (!weakCompareAndSetLongRelease(o, offset, 2655 expectedBits, Double.doubleToRawLongBits(v + delta))); 2656 return v; 2657 } 2658 2659 @ForceInline 2660 public final double getAndAddDoubleAcquire(Object o, long offset, double delta) { 2661 long expectedBits; 2662 double v; 2663 do { 2664 // Load and CAS with the raw bits to avoid issues with NaNs and 2665 // possible bit conversion from signaling NaNs to quiet NaNs that 2666 // may result in the loop not terminating. 2667 expectedBits = getLongAcquire(o, offset); 2668 v = Double.longBitsToDouble(expectedBits); 2669 } while (!weakCompareAndSetLongAcquire(o, offset, 2670 expectedBits, Double.doubleToRawLongBits(v + delta))); 2671 return v; 2672 } 2673 2674 /** 2675 * Atomically exchanges the given value with the current value of 2676 * a field or array element within the given object {@code o} 2677 * at the given {@code offset}. 2678 * 2679 * @param o object/array to update the field/element in 2680 * @param offset field/element offset 2681 * @param newValue new value 2682 * @return the previous value 2683 * @since 1.8 2684 */ 2685 @IntrinsicCandidate 2686 public final int getAndSetInt(Object o, long offset, int newValue) { 2687 int v; 2688 do { 2689 v = getIntVolatile(o, offset); 2690 } while (!weakCompareAndSetInt(o, offset, v, newValue)); 2691 return v; 2692 } 2693 2694 @ForceInline 2695 public final int getAndSetIntRelease(Object o, long offset, int newValue) { 2696 int v; 2697 do { 2698 v = getInt(o, offset); 2699 } while (!weakCompareAndSetIntRelease(o, offset, v, newValue)); 2700 return v; 2701 } 2702 2703 @ForceInline 2704 public final int getAndSetIntAcquire(Object o, long offset, int newValue) { 2705 int v; 2706 do { 2707 v = getIntAcquire(o, offset); 2708 } while (!weakCompareAndSetIntAcquire(o, offset, v, newValue)); 2709 return v; 2710 } 2711 2712 /** 2713 * Atomically exchanges the given value with the current value of 2714 * a field or array element within the given object {@code o} 2715 * at the given {@code offset}. 2716 * 2717 * @param o object/array to update the field/element in 2718 * @param offset field/element offset 2719 * @param newValue new value 2720 * @return the previous value 2721 * @since 1.8 2722 */ 2723 @IntrinsicCandidate 2724 public final long getAndSetLong(Object o, long offset, long newValue) { 2725 long v; 2726 do { 2727 v = getLongVolatile(o, offset); 2728 } while (!weakCompareAndSetLong(o, offset, v, newValue)); 2729 return v; 2730 } 2731 2732 @ForceInline 2733 public final long getAndSetLongRelease(Object o, long offset, long newValue) { 2734 long v; 2735 do { 2736 v = getLong(o, offset); 2737 } while (!weakCompareAndSetLongRelease(o, offset, v, newValue)); 2738 return v; 2739 } 2740 2741 @ForceInline 2742 public final long getAndSetLongAcquire(Object o, long offset, long newValue) { 2743 long v; 2744 do { 2745 v = getLongAcquire(o, offset); 2746 } while (!weakCompareAndSetLongAcquire(o, offset, v, newValue)); 2747 return v; 2748 } 2749 2750 /** 2751 * Atomically exchanges the given reference value with the current 2752 * reference value of a field or array element within the given 2753 * object {@code o} at the given {@code offset}. 2754 * 2755 * @param o object/array to update the field/element in 2756 * @param offset field/element offset 2757 * @param newValue new value 2758 * @return the previous value 2759 * @since 1.8 2760 */ 2761 @IntrinsicCandidate 2762 public final Object getAndSetReference(Object o, long offset, Object newValue) { 2763 Object v; 2764 do { 2765 v = getReferenceVolatile(o, offset); 2766 } while (!weakCompareAndSetReference(o, offset, v, newValue)); 2767 return v; 2768 } 2769 2770 @ForceInline 2771 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) { 2772 Object v; 2773 do { 2774 v = getReference(o, offset); 2775 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue)); 2776 return v; 2777 } 2778 2779 @ForceInline 2780 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) { 2781 Object v; 2782 do { 2783 v = getReferenceAcquire(o, offset); 2784 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue)); 2785 return v; 2786 } 2787 2788 @IntrinsicCandidate 2789 public final byte getAndSetByte(Object o, long offset, byte newValue) { 2790 byte v; 2791 do { 2792 v = getByteVolatile(o, offset); 2793 } while (!weakCompareAndSetByte(o, offset, v, newValue)); 2794 return v; 2795 } 2796 2797 @ForceInline 2798 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) { 2799 byte v; 2800 do { 2801 v = getByte(o, offset); 2802 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue)); 2803 return v; 2804 } 2805 2806 @ForceInline 2807 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) { 2808 byte v; 2809 do { 2810 v = getByteAcquire(o, offset); 2811 } while (!weakCompareAndSetByteAcquire(o, offset, v, newValue)); 2812 return v; 2813 } 2814 2815 @ForceInline 2816 public final boolean getAndSetBoolean(Object o, long offset, boolean newValue) { 2817 return byte2bool(getAndSetByte(o, offset, bool2byte(newValue))); 2818 } 2819 2820 @ForceInline 2821 public final boolean getAndSetBooleanRelease(Object o, long offset, boolean newValue) { 2822 return byte2bool(getAndSetByteRelease(o, offset, bool2byte(newValue))); 2823 } 2824 2825 @ForceInline 2826 public final boolean getAndSetBooleanAcquire(Object o, long offset, boolean newValue) { 2827 return byte2bool(getAndSetByteAcquire(o, offset, bool2byte(newValue))); 2828 } 2829 2830 @IntrinsicCandidate 2831 public final short getAndSetShort(Object o, long offset, short newValue) { 2832 short v; 2833 do { 2834 v = getShortVolatile(o, offset); 2835 } while (!weakCompareAndSetShort(o, offset, v, newValue)); 2836 return v; 2837 } 2838 2839 @ForceInline 2840 public final short getAndSetShortRelease(Object o, long offset, short newValue) { 2841 short v; 2842 do { 2843 v = getShort(o, offset); 2844 } while (!weakCompareAndSetShortRelease(o, offset, v, newValue)); 2845 return v; 2846 } 2847 2848 @ForceInline 2849 public final short getAndSetShortAcquire(Object o, long offset, short newValue) { 2850 short v; 2851 do { 2852 v = getShortAcquire(o, offset); 2853 } while (!weakCompareAndSetShortAcquire(o, offset, v, newValue)); 2854 return v; 2855 } 2856 2857 @ForceInline 2858 public final char getAndSetChar(Object o, long offset, char newValue) { 2859 return s2c(getAndSetShort(o, offset, c2s(newValue))); 2860 } 2861 2862 @ForceInline 2863 public final char getAndSetCharRelease(Object o, long offset, char newValue) { 2864 return s2c(getAndSetShortRelease(o, offset, c2s(newValue))); 2865 } 2866 2867 @ForceInline 2868 public final char getAndSetCharAcquire(Object o, long offset, char newValue) { 2869 return s2c(getAndSetShortAcquire(o, offset, c2s(newValue))); 2870 } 2871 2872 @ForceInline 2873 public final float getAndSetFloat(Object o, long offset, float newValue) { 2874 int v = getAndSetInt(o, offset, Float.floatToRawIntBits(newValue)); 2875 return Float.intBitsToFloat(v); 2876 } 2877 2878 @ForceInline 2879 public final float getAndSetFloatRelease(Object o, long offset, float newValue) { 2880 int v = getAndSetIntRelease(o, offset, Float.floatToRawIntBits(newValue)); 2881 return Float.intBitsToFloat(v); 2882 } 2883 2884 @ForceInline 2885 public final float getAndSetFloatAcquire(Object o, long offset, float newValue) { 2886 int v = getAndSetIntAcquire(o, offset, Float.floatToRawIntBits(newValue)); 2887 return Float.intBitsToFloat(v); 2888 } 2889 2890 @ForceInline 2891 public final double getAndSetDouble(Object o, long offset, double newValue) { 2892 long v = getAndSetLong(o, offset, Double.doubleToRawLongBits(newValue)); 2893 return Double.longBitsToDouble(v); 2894 } 2895 2896 @ForceInline 2897 public final double getAndSetDoubleRelease(Object o, long offset, double newValue) { 2898 long v = getAndSetLongRelease(o, offset, Double.doubleToRawLongBits(newValue)); 2899 return Double.longBitsToDouble(v); 2900 } 2901 2902 @ForceInline 2903 public final double getAndSetDoubleAcquire(Object o, long offset, double newValue) { 2904 long v = getAndSetLongAcquire(o, offset, Double.doubleToRawLongBits(newValue)); 2905 return Double.longBitsToDouble(v); 2906 } 2907 2908 2909 // The following contain CAS-based Java implementations used on 2910 // platforms not supporting native instructions 2911 2912 @ForceInline 2913 public final boolean getAndBitwiseOrBoolean(Object o, long offset, boolean mask) { 2914 return byte2bool(getAndBitwiseOrByte(o, offset, bool2byte(mask))); 2915 } 2916 2917 @ForceInline 2918 public final boolean getAndBitwiseOrBooleanRelease(Object o, long offset, boolean mask) { 2919 return byte2bool(getAndBitwiseOrByteRelease(o, offset, bool2byte(mask))); 2920 } 2921 2922 @ForceInline 2923 public final boolean getAndBitwiseOrBooleanAcquire(Object o, long offset, boolean mask) { 2924 return byte2bool(getAndBitwiseOrByteAcquire(o, offset, bool2byte(mask))); 2925 } 2926 2927 @ForceInline 2928 public final boolean getAndBitwiseAndBoolean(Object o, long offset, boolean mask) { 2929 return byte2bool(getAndBitwiseAndByte(o, offset, bool2byte(mask))); 2930 } 2931 2932 @ForceInline 2933 public final boolean getAndBitwiseAndBooleanRelease(Object o, long offset, boolean mask) { 2934 return byte2bool(getAndBitwiseAndByteRelease(o, offset, bool2byte(mask))); 2935 } 2936 2937 @ForceInline 2938 public final boolean getAndBitwiseAndBooleanAcquire(Object o, long offset, boolean mask) { 2939 return byte2bool(getAndBitwiseAndByteAcquire(o, offset, bool2byte(mask))); 2940 } 2941 2942 @ForceInline 2943 public final boolean getAndBitwiseXorBoolean(Object o, long offset, boolean mask) { 2944 return byte2bool(getAndBitwiseXorByte(o, offset, bool2byte(mask))); 2945 } 2946 2947 @ForceInline 2948 public final boolean getAndBitwiseXorBooleanRelease(Object o, long offset, boolean mask) { 2949 return byte2bool(getAndBitwiseXorByteRelease(o, offset, bool2byte(mask))); 2950 } 2951 2952 @ForceInline 2953 public final boolean getAndBitwiseXorBooleanAcquire(Object o, long offset, boolean mask) { 2954 return byte2bool(getAndBitwiseXorByteAcquire(o, offset, bool2byte(mask))); 2955 } 2956 2957 2958 @ForceInline 2959 public final byte getAndBitwiseOrByte(Object o, long offset, byte mask) { 2960 byte current; 2961 do { 2962 current = getByteVolatile(o, offset); 2963 } while (!weakCompareAndSetByte(o, offset, 2964 current, (byte) (current | mask))); 2965 return current; 2966 } 2967 2968 @ForceInline 2969 public final byte getAndBitwiseOrByteRelease(Object o, long offset, byte mask) { 2970 byte current; 2971 do { 2972 current = getByte(o, offset); 2973 } while (!weakCompareAndSetByteRelease(o, offset, 2974 current, (byte) (current | mask))); 2975 return current; 2976 } 2977 2978 @ForceInline 2979 public final byte getAndBitwiseOrByteAcquire(Object o, long offset, byte mask) { 2980 byte current; 2981 do { 2982 // Plain read, the value is a hint, the acquire CAS does the work 2983 current = getByte(o, offset); 2984 } while (!weakCompareAndSetByteAcquire(o, offset, 2985 current, (byte) (current | mask))); 2986 return current; 2987 } 2988 2989 @ForceInline 2990 public final byte getAndBitwiseAndByte(Object o, long offset, byte mask) { 2991 byte current; 2992 do { 2993 current = getByteVolatile(o, offset); 2994 } while (!weakCompareAndSetByte(o, offset, 2995 current, (byte) (current & mask))); 2996 return current; 2997 } 2998 2999 @ForceInline 3000 public final byte getAndBitwiseAndByteRelease(Object o, long offset, byte mask) { 3001 byte current; 3002 do { 3003 current = getByte(o, offset); 3004 } while (!weakCompareAndSetByteRelease(o, offset, 3005 current, (byte) (current & mask))); 3006 return current; 3007 } 3008 3009 @ForceInline 3010 public final byte getAndBitwiseAndByteAcquire(Object o, long offset, byte mask) { 3011 byte current; 3012 do { 3013 // Plain read, the value is a hint, the acquire CAS does the work 3014 current = getByte(o, offset); 3015 } while (!weakCompareAndSetByteAcquire(o, offset, 3016 current, (byte) (current & mask))); 3017 return current; 3018 } 3019 3020 @ForceInline 3021 public final byte getAndBitwiseXorByte(Object o, long offset, byte mask) { 3022 byte current; 3023 do { 3024 current = getByteVolatile(o, offset); 3025 } while (!weakCompareAndSetByte(o, offset, 3026 current, (byte) (current ^ mask))); 3027 return current; 3028 } 3029 3030 @ForceInline 3031 public final byte getAndBitwiseXorByteRelease(Object o, long offset, byte mask) { 3032 byte current; 3033 do { 3034 current = getByte(o, offset); 3035 } while (!weakCompareAndSetByteRelease(o, offset, 3036 current, (byte) (current ^ mask))); 3037 return current; 3038 } 3039 3040 @ForceInline 3041 public final byte getAndBitwiseXorByteAcquire(Object o, long offset, byte mask) { 3042 byte current; 3043 do { 3044 // Plain read, the value is a hint, the acquire CAS does the work 3045 current = getByte(o, offset); 3046 } while (!weakCompareAndSetByteAcquire(o, offset, 3047 current, (byte) (current ^ mask))); 3048 return current; 3049 } 3050 3051 3052 @ForceInline 3053 public final char getAndBitwiseOrChar(Object o, long offset, char mask) { 3054 return s2c(getAndBitwiseOrShort(o, offset, c2s(mask))); 3055 } 3056 3057 @ForceInline 3058 public final char getAndBitwiseOrCharRelease(Object o, long offset, char mask) { 3059 return s2c(getAndBitwiseOrShortRelease(o, offset, c2s(mask))); 3060 } 3061 3062 @ForceInline 3063 public final char getAndBitwiseOrCharAcquire(Object o, long offset, char mask) { 3064 return s2c(getAndBitwiseOrShortAcquire(o, offset, c2s(mask))); 3065 } 3066 3067 @ForceInline 3068 public final char getAndBitwiseAndChar(Object o, long offset, char mask) { 3069 return s2c(getAndBitwiseAndShort(o, offset, c2s(mask))); 3070 } 3071 3072 @ForceInline 3073 public final char getAndBitwiseAndCharRelease(Object o, long offset, char mask) { 3074 return s2c(getAndBitwiseAndShortRelease(o, offset, c2s(mask))); 3075 } 3076 3077 @ForceInline 3078 public final char getAndBitwiseAndCharAcquire(Object o, long offset, char mask) { 3079 return s2c(getAndBitwiseAndShortAcquire(o, offset, c2s(mask))); 3080 } 3081 3082 @ForceInline 3083 public final char getAndBitwiseXorChar(Object o, long offset, char mask) { 3084 return s2c(getAndBitwiseXorShort(o, offset, c2s(mask))); 3085 } 3086 3087 @ForceInline 3088 public final char getAndBitwiseXorCharRelease(Object o, long offset, char mask) { 3089 return s2c(getAndBitwiseXorShortRelease(o, offset, c2s(mask))); 3090 } 3091 3092 @ForceInline 3093 public final char getAndBitwiseXorCharAcquire(Object o, long offset, char mask) { 3094 return s2c(getAndBitwiseXorShortAcquire(o, offset, c2s(mask))); 3095 } 3096 3097 3098 @ForceInline 3099 public final short getAndBitwiseOrShort(Object o, long offset, short mask) { 3100 short current; 3101 do { 3102 current = getShortVolatile(o, offset); 3103 } while (!weakCompareAndSetShort(o, offset, 3104 current, (short) (current | mask))); 3105 return current; 3106 } 3107 3108 @ForceInline 3109 public final short getAndBitwiseOrShortRelease(Object o, long offset, short mask) { 3110 short current; 3111 do { 3112 current = getShort(o, offset); 3113 } while (!weakCompareAndSetShortRelease(o, offset, 3114 current, (short) (current | mask))); 3115 return current; 3116 } 3117 3118 @ForceInline 3119 public final short getAndBitwiseOrShortAcquire(Object o, long offset, short mask) { 3120 short current; 3121 do { 3122 // Plain read, the value is a hint, the acquire CAS does the work 3123 current = getShort(o, offset); 3124 } while (!weakCompareAndSetShortAcquire(o, offset, 3125 current, (short) (current | mask))); 3126 return current; 3127 } 3128 3129 @ForceInline 3130 public final short getAndBitwiseAndShort(Object o, long offset, short mask) { 3131 short current; 3132 do { 3133 current = getShortVolatile(o, offset); 3134 } while (!weakCompareAndSetShort(o, offset, 3135 current, (short) (current & mask))); 3136 return current; 3137 } 3138 3139 @ForceInline 3140 public final short getAndBitwiseAndShortRelease(Object o, long offset, short mask) { 3141 short current; 3142 do { 3143 current = getShort(o, offset); 3144 } while (!weakCompareAndSetShortRelease(o, offset, 3145 current, (short) (current & mask))); 3146 return current; 3147 } 3148 3149 @ForceInline 3150 public final short getAndBitwiseAndShortAcquire(Object o, long offset, short mask) { 3151 short current; 3152 do { 3153 // Plain read, the value is a hint, the acquire CAS does the work 3154 current = getShort(o, offset); 3155 } while (!weakCompareAndSetShortAcquire(o, offset, 3156 current, (short) (current & mask))); 3157 return current; 3158 } 3159 3160 @ForceInline 3161 public final short getAndBitwiseXorShort(Object o, long offset, short mask) { 3162 short current; 3163 do { 3164 current = getShortVolatile(o, offset); 3165 } while (!weakCompareAndSetShort(o, offset, 3166 current, (short) (current ^ mask))); 3167 return current; 3168 } 3169 3170 @ForceInline 3171 public final short getAndBitwiseXorShortRelease(Object o, long offset, short mask) { 3172 short current; 3173 do { 3174 current = getShort(o, offset); 3175 } while (!weakCompareAndSetShortRelease(o, offset, 3176 current, (short) (current ^ mask))); 3177 return current; 3178 } 3179 3180 @ForceInline 3181 public final short getAndBitwiseXorShortAcquire(Object o, long offset, short mask) { 3182 short current; 3183 do { 3184 // Plain read, the value is a hint, the acquire CAS does the work 3185 current = getShort(o, offset); 3186 } while (!weakCompareAndSetShortAcquire(o, offset, 3187 current, (short) (current ^ mask))); 3188 return current; 3189 } 3190 3191 3192 @ForceInline 3193 public final int getAndBitwiseOrInt(Object o, long offset, int mask) { 3194 int current; 3195 do { 3196 current = getIntVolatile(o, offset); 3197 } while (!weakCompareAndSetInt(o, offset, 3198 current, current | mask)); 3199 return current; 3200 } 3201 3202 @ForceInline 3203 public final int getAndBitwiseOrIntRelease(Object o, long offset, int mask) { 3204 int current; 3205 do { 3206 current = getInt(o, offset); 3207 } while (!weakCompareAndSetIntRelease(o, offset, 3208 current, current | mask)); 3209 return current; 3210 } 3211 3212 @ForceInline 3213 public final int getAndBitwiseOrIntAcquire(Object o, long offset, int mask) { 3214 int current; 3215 do { 3216 // Plain read, the value is a hint, the acquire CAS does the work 3217 current = getInt(o, offset); 3218 } while (!weakCompareAndSetIntAcquire(o, offset, 3219 current, current | mask)); 3220 return current; 3221 } 3222 3223 /** 3224 * Atomically replaces the current value of a field or array element within 3225 * the given object with the result of bitwise AND between the current value 3226 * and mask. 3227 * 3228 * @param o object/array to update the field/element in 3229 * @param offset field/element offset 3230 * @param mask the mask value 3231 * @return the previous value 3232 * @since 9 3233 */ 3234 @ForceInline 3235 public final int getAndBitwiseAndInt(Object o, long offset, int mask) { 3236 int current; 3237 do { 3238 current = getIntVolatile(o, offset); 3239 } while (!weakCompareAndSetInt(o, offset, 3240 current, current & mask)); 3241 return current; 3242 } 3243 3244 @ForceInline 3245 public final int getAndBitwiseAndIntRelease(Object o, long offset, int mask) { 3246 int current; 3247 do { 3248 current = getInt(o, offset); 3249 } while (!weakCompareAndSetIntRelease(o, offset, 3250 current, current & mask)); 3251 return current; 3252 } 3253 3254 @ForceInline 3255 public final int getAndBitwiseAndIntAcquire(Object o, long offset, int mask) { 3256 int current; 3257 do { 3258 // Plain read, the value is a hint, the acquire CAS does the work 3259 current = getInt(o, offset); 3260 } while (!weakCompareAndSetIntAcquire(o, offset, 3261 current, current & mask)); 3262 return current; 3263 } 3264 3265 @ForceInline 3266 public final int getAndBitwiseXorInt(Object o, long offset, int mask) { 3267 int current; 3268 do { 3269 current = getIntVolatile(o, offset); 3270 } while (!weakCompareAndSetInt(o, offset, 3271 current, current ^ mask)); 3272 return current; 3273 } 3274 3275 @ForceInline 3276 public final int getAndBitwiseXorIntRelease(Object o, long offset, int mask) { 3277 int current; 3278 do { 3279 current = getInt(o, offset); 3280 } while (!weakCompareAndSetIntRelease(o, offset, 3281 current, current ^ mask)); 3282 return current; 3283 } 3284 3285 @ForceInline 3286 public final int getAndBitwiseXorIntAcquire(Object o, long offset, int mask) { 3287 int current; 3288 do { 3289 // Plain read, the value is a hint, the acquire CAS does the work 3290 current = getInt(o, offset); 3291 } while (!weakCompareAndSetIntAcquire(o, offset, 3292 current, current ^ mask)); 3293 return current; 3294 } 3295 3296 3297 @ForceInline 3298 public final long getAndBitwiseOrLong(Object o, long offset, long mask) { 3299 long current; 3300 do { 3301 current = getLongVolatile(o, offset); 3302 } while (!weakCompareAndSetLong(o, offset, 3303 current, current | mask)); 3304 return current; 3305 } 3306 3307 @ForceInline 3308 public final long getAndBitwiseOrLongRelease(Object o, long offset, long mask) { 3309 long current; 3310 do { 3311 current = getLong(o, offset); 3312 } while (!weakCompareAndSetLongRelease(o, offset, 3313 current, current | mask)); 3314 return current; 3315 } 3316 3317 @ForceInline 3318 public final long getAndBitwiseOrLongAcquire(Object o, long offset, long mask) { 3319 long current; 3320 do { 3321 // Plain read, the value is a hint, the acquire CAS does the work 3322 current = getLong(o, offset); 3323 } while (!weakCompareAndSetLongAcquire(o, offset, 3324 current, current | mask)); 3325 return current; 3326 } 3327 3328 @ForceInline 3329 public final long getAndBitwiseAndLong(Object o, long offset, long mask) { 3330 long current; 3331 do { 3332 current = getLongVolatile(o, offset); 3333 } while (!weakCompareAndSetLong(o, offset, 3334 current, current & mask)); 3335 return current; 3336 } 3337 3338 @ForceInline 3339 public final long getAndBitwiseAndLongRelease(Object o, long offset, long mask) { 3340 long current; 3341 do { 3342 current = getLong(o, offset); 3343 } while (!weakCompareAndSetLongRelease(o, offset, 3344 current, current & mask)); 3345 return current; 3346 } 3347 3348 @ForceInline 3349 public final long getAndBitwiseAndLongAcquire(Object o, long offset, long mask) { 3350 long current; 3351 do { 3352 // Plain read, the value is a hint, the acquire CAS does the work 3353 current = getLong(o, offset); 3354 } while (!weakCompareAndSetLongAcquire(o, offset, 3355 current, current & mask)); 3356 return current; 3357 } 3358 3359 @ForceInline 3360 public final long getAndBitwiseXorLong(Object o, long offset, long mask) { 3361 long current; 3362 do { 3363 current = getLongVolatile(o, offset); 3364 } while (!weakCompareAndSetLong(o, offset, 3365 current, current ^ mask)); 3366 return current; 3367 } 3368 3369 @ForceInline 3370 public final long getAndBitwiseXorLongRelease(Object o, long offset, long mask) { 3371 long current; 3372 do { 3373 current = getLong(o, offset); 3374 } while (!weakCompareAndSetLongRelease(o, offset, 3375 current, current ^ mask)); 3376 return current; 3377 } 3378 3379 @ForceInline 3380 public final long getAndBitwiseXorLongAcquire(Object o, long offset, long mask) { 3381 long current; 3382 do { 3383 // Plain read, the value is a hint, the acquire CAS does the work 3384 current = getLong(o, offset); 3385 } while (!weakCompareAndSetLongAcquire(o, offset, 3386 current, current ^ mask)); 3387 return current; 3388 } 3389 3390 3391 3392 /** 3393 * Ensures that loads before the fence will not be reordered with loads and 3394 * stores after the fence; a "LoadLoad plus LoadStore barrier". 3395 * 3396 * Corresponds to C11 atomic_thread_fence(memory_order_acquire) 3397 * (an "acquire fence"). 3398 * 3399 * Provides a LoadLoad barrier followed by a LoadStore barrier. 3400 * 3401 * @since 1.8 3402 */ 3403 @IntrinsicCandidate 3404 public final void loadFence() { 3405 // If loadFence intrinsic is not available, fall back to full fence. 3406 fullFence(); 3407 } 3408 3409 /** 3410 * Ensures that loads and stores before the fence will not be reordered with 3411 * stores after the fence; a "StoreStore plus LoadStore barrier". 3412 * 3413 * Corresponds to C11 atomic_thread_fence(memory_order_release) 3414 * (a "release fence"). 3415 * 3416 * Provides a StoreStore barrier followed by a LoadStore barrier. 3417 * 3418 * @since 1.8 3419 */ 3420 @IntrinsicCandidate 3421 public final void storeFence() { 3422 // If storeFence intrinsic is not available, fall back to full fence. 3423 fullFence(); 3424 } 3425 3426 /** 3427 * Ensures that loads and stores before the fence will not be reordered 3428 * with loads and stores after the fence. Implies the effects of both 3429 * loadFence() and storeFence(), and in addition, the effect of a StoreLoad 3430 * barrier. 3431 * 3432 * Corresponds to C11 atomic_thread_fence(memory_order_seq_cst). 3433 * @since 1.8 3434 */ 3435 @IntrinsicCandidate 3436 public native void fullFence(); 3437 3438 /** 3439 * Ensures that loads before the fence will not be reordered with 3440 * loads after the fence. 3441 * 3442 * @implNote 3443 * This method is operationally equivalent to {@link #loadFence()}. 3444 * 3445 * @since 9 3446 */ 3447 public final void loadLoadFence() { 3448 loadFence(); 3449 } 3450 3451 /** 3452 * Ensures that stores before the fence will not be reordered with 3453 * stores after the fence. 3454 * 3455 * @since 9 3456 */ 3457 @IntrinsicCandidate 3458 public final void storeStoreFence() { 3459 // If storeStoreFence intrinsic is not available, fall back to storeFence. 3460 storeFence(); 3461 } 3462 3463 /** 3464 * Throws IllegalAccessError; for use by the VM for access control 3465 * error support. 3466 * @since 1.8 3467 */ 3468 private static void throwIllegalAccessError() { 3469 throw new IllegalAccessError(); 3470 } 3471 3472 /** 3473 * Throws NoSuchMethodError; for use by the VM for redefinition support. 3474 * @since 13 3475 */ 3476 private static void throwNoSuchMethodError() { 3477 throw new NoSuchMethodError(); 3478 } 3479 3480 /** 3481 * @return Returns true if the native byte ordering of this 3482 * platform is big-endian, false if it is little-endian. 3483 */ 3484 public final boolean isBigEndian() { return BIG_ENDIAN; } 3485 3486 /** 3487 * @return Returns true if this platform is capable of performing 3488 * accesses at addresses which are not aligned for the type of the 3489 * primitive type being accessed, false otherwise. 3490 */ 3491 public final boolean unalignedAccess() { return UNALIGNED_ACCESS; } 3492 3493 /** 3494 * Fetches a value at some byte offset into a given Java object. 3495 * More specifically, fetches a value within the given object 3496 * <code>o</code> at the given offset, or (if <code>o</code> is 3497 * null) from the memory address whose numerical value is the 3498 * given offset. <p> 3499 * 3500 * The specification of this method is the same as {@link 3501 * #getLong(Object, long)} except that the offset does not need to 3502 * have been obtained from {@link #objectFieldOffset} on the 3503 * {@link java.lang.reflect.Field} of some Java field. The value 3504 * in memory is raw data, and need not correspond to any Java 3505 * variable. Unless <code>o</code> is null, the value accessed 3506 * must be entirely within the allocated object. The endianness 3507 * of the value in memory is the endianness of the native platform. 3508 * 3509 * <p> The read will be atomic with respect to the largest power 3510 * of two that divides the GCD of the offset and the storage size. 3511 * For example, getLongUnaligned will make atomic reads of 2-, 4-, 3512 * or 8-byte storage units if the offset is zero mod 2, 4, or 8, 3513 * respectively. There are no other guarantees of atomicity. 3514 * <p> 3515 * 8-byte atomicity is only guaranteed on platforms on which 3516 * support atomic accesses to longs. 3517 * 3518 * @param o Java heap object in which the value resides, if any, else 3519 * null 3520 * @param offset The offset in bytes from the start of the object 3521 * @return the value fetched from the indicated object 3522 * @throws RuntimeException No defined exceptions are thrown, not even 3523 * {@link NullPointerException} 3524 * @since 9 3525 */ 3526 @IntrinsicCandidate 3527 public final long getLongUnaligned(Object o, long offset) { 3528 if ((offset & 7) == 0) { 3529 return getLong(o, offset); 3530 } else if ((offset & 3) == 0) { 3531 return makeLong(getInt(o, offset), 3532 getInt(o, offset + 4)); 3533 } else if ((offset & 1) == 0) { 3534 return makeLong(getShort(o, offset), 3535 getShort(o, offset + 2), 3536 getShort(o, offset + 4), 3537 getShort(o, offset + 6)); 3538 } else { 3539 return makeLong(getByte(o, offset), 3540 getByte(o, offset + 1), 3541 getByte(o, offset + 2), 3542 getByte(o, offset + 3), 3543 getByte(o, offset + 4), 3544 getByte(o, offset + 5), 3545 getByte(o, offset + 6), 3546 getByte(o, offset + 7)); 3547 } 3548 } 3549 /** 3550 * As {@link #getLongUnaligned(Object, long)} but with an 3551 * additional argument which specifies the endianness of the value 3552 * as stored in memory. 3553 * 3554 * @param o Java heap object in which the variable resides 3555 * @param offset The offset in bytes from the start of the object 3556 * @param bigEndian The endianness of the value 3557 * @return the value fetched from the indicated object 3558 * @since 9 3559 */ 3560 public final long getLongUnaligned(Object o, long offset, boolean bigEndian) { 3561 return convEndian(bigEndian, getLongUnaligned(o, offset)); 3562 } 3563 3564 /** @see #getLongUnaligned(Object, long) */ 3565 @IntrinsicCandidate 3566 public final int getIntUnaligned(Object o, long offset) { 3567 if ((offset & 3) == 0) { 3568 return getInt(o, offset); 3569 } else if ((offset & 1) == 0) { 3570 return makeInt(getShort(o, offset), 3571 getShort(o, offset + 2)); 3572 } else { 3573 return makeInt(getByte(o, offset), 3574 getByte(o, offset + 1), 3575 getByte(o, offset + 2), 3576 getByte(o, offset + 3)); 3577 } 3578 } 3579 /** @see #getLongUnaligned(Object, long, boolean) */ 3580 public final int getIntUnaligned(Object o, long offset, boolean bigEndian) { 3581 return convEndian(bigEndian, getIntUnaligned(o, offset)); 3582 } 3583 3584 /** @see #getLongUnaligned(Object, long) */ 3585 @IntrinsicCandidate 3586 public final short getShortUnaligned(Object o, long offset) { 3587 if ((offset & 1) == 0) { 3588 return getShort(o, offset); 3589 } else { 3590 return makeShort(getByte(o, offset), 3591 getByte(o, offset + 1)); 3592 } 3593 } 3594 /** @see #getLongUnaligned(Object, long, boolean) */ 3595 public final short getShortUnaligned(Object o, long offset, boolean bigEndian) { 3596 return convEndian(bigEndian, getShortUnaligned(o, offset)); 3597 } 3598 3599 /** @see #getLongUnaligned(Object, long) */ 3600 @IntrinsicCandidate 3601 public final char getCharUnaligned(Object o, long offset) { 3602 if ((offset & 1) == 0) { 3603 return getChar(o, offset); 3604 } else { 3605 return (char)makeShort(getByte(o, offset), 3606 getByte(o, offset + 1)); 3607 } 3608 } 3609 3610 /** @see #getLongUnaligned(Object, long, boolean) */ 3611 public final char getCharUnaligned(Object o, long offset, boolean bigEndian) { 3612 return convEndian(bigEndian, getCharUnaligned(o, offset)); 3613 } 3614 3615 /** 3616 * Stores a value at some byte offset into a given Java object. 3617 * <p> 3618 * The specification of this method is the same as {@link 3619 * #getLong(Object, long)} except that the offset does not need to 3620 * have been obtained from {@link #objectFieldOffset} on the 3621 * {@link java.lang.reflect.Field} of some Java field. The value 3622 * in memory is raw data, and need not correspond to any Java 3623 * variable. The endianness of the value in memory is the 3624 * endianness of the native platform. 3625 * <p> 3626 * The write will be atomic with respect to the largest power of 3627 * two that divides the GCD of the offset and the storage size. 3628 * For example, putLongUnaligned will make atomic writes of 2-, 4-, 3629 * or 8-byte storage units if the offset is zero mod 2, 4, or 8, 3630 * respectively. There are no other guarantees of atomicity. 3631 * <p> 3632 * 8-byte atomicity is only guaranteed on platforms on which 3633 * support atomic accesses to longs. 3634 * 3635 * @param o Java heap object in which the value resides, if any, else 3636 * null 3637 * @param offset The offset in bytes from the start of the object 3638 * @param x the value to store 3639 * @throws RuntimeException No defined exceptions are thrown, not even 3640 * {@link NullPointerException} 3641 * @since 9 3642 */ 3643 @IntrinsicCandidate 3644 public final void putLongUnaligned(Object o, long offset, long x) { 3645 if ((offset & 7) == 0) { 3646 putLong(o, offset, x); 3647 } else if ((offset & 3) == 0) { 3648 putLongParts(o, offset, 3649 (int)(x >> 0), 3650 (int)(x >>> 32)); 3651 } else if ((offset & 1) == 0) { 3652 putLongParts(o, offset, 3653 (short)(x >>> 0), 3654 (short)(x >>> 16), 3655 (short)(x >>> 32), 3656 (short)(x >>> 48)); 3657 } else { 3658 putLongParts(o, offset, 3659 (byte)(x >>> 0), 3660 (byte)(x >>> 8), 3661 (byte)(x >>> 16), 3662 (byte)(x >>> 24), 3663 (byte)(x >>> 32), 3664 (byte)(x >>> 40), 3665 (byte)(x >>> 48), 3666 (byte)(x >>> 56)); 3667 } 3668 } 3669 3670 /** 3671 * As {@link #putLongUnaligned(Object, long, long)} but with an additional 3672 * argument which specifies the endianness of the value as stored in memory. 3673 * @param o Java heap object in which the value resides 3674 * @param offset The offset in bytes from the start of the object 3675 * @param x the value to store 3676 * @param bigEndian The endianness of the value 3677 * @throws RuntimeException No defined exceptions are thrown, not even 3678 * {@link NullPointerException} 3679 * @since 9 3680 */ 3681 public final void putLongUnaligned(Object o, long offset, long x, boolean bigEndian) { 3682 putLongUnaligned(o, offset, convEndian(bigEndian, x)); 3683 } 3684 3685 /** @see #putLongUnaligned(Object, long, long) */ 3686 @IntrinsicCandidate 3687 public final void putIntUnaligned(Object o, long offset, int x) { 3688 if ((offset & 3) == 0) { 3689 putInt(o, offset, x); 3690 } else if ((offset & 1) == 0) { 3691 putIntParts(o, offset, 3692 (short)(x >> 0), 3693 (short)(x >>> 16)); 3694 } else { 3695 putIntParts(o, offset, 3696 (byte)(x >>> 0), 3697 (byte)(x >>> 8), 3698 (byte)(x >>> 16), 3699 (byte)(x >>> 24)); 3700 } 3701 } 3702 /** @see #putLongUnaligned(Object, long, long, boolean) */ 3703 public final void putIntUnaligned(Object o, long offset, int x, boolean bigEndian) { 3704 putIntUnaligned(o, offset, convEndian(bigEndian, x)); 3705 } 3706 3707 /** @see #putLongUnaligned(Object, long, long) */ 3708 @IntrinsicCandidate 3709 public final void putShortUnaligned(Object o, long offset, short x) { 3710 if ((offset & 1) == 0) { 3711 putShort(o, offset, x); 3712 } else { 3713 putShortParts(o, offset, 3714 (byte)(x >>> 0), 3715 (byte)(x >>> 8)); 3716 } 3717 } 3718 /** @see #putLongUnaligned(Object, long, long, boolean) */ 3719 public final void putShortUnaligned(Object o, long offset, short x, boolean bigEndian) { 3720 putShortUnaligned(o, offset, convEndian(bigEndian, x)); 3721 } 3722 3723 /** @see #putLongUnaligned(Object, long, long) */ 3724 @IntrinsicCandidate 3725 public final void putCharUnaligned(Object o, long offset, char x) { 3726 putShortUnaligned(o, offset, (short)x); 3727 } 3728 /** @see #putLongUnaligned(Object, long, long, boolean) */ 3729 public final void putCharUnaligned(Object o, long offset, char x, boolean bigEndian) { 3730 putCharUnaligned(o, offset, convEndian(bigEndian, x)); 3731 } 3732 3733 private static int pickPos(int top, int pos) { return BIG_ENDIAN ? top - pos : pos; } 3734 3735 // These methods construct integers from bytes. The byte ordering 3736 // is the native endianness of this platform. 3737 private static long makeLong(byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) { 3738 return ((toUnsignedLong(i0) << pickPos(56, 0)) 3739 | (toUnsignedLong(i1) << pickPos(56, 8)) 3740 | (toUnsignedLong(i2) << pickPos(56, 16)) 3741 | (toUnsignedLong(i3) << pickPos(56, 24)) 3742 | (toUnsignedLong(i4) << pickPos(56, 32)) 3743 | (toUnsignedLong(i5) << pickPos(56, 40)) 3744 | (toUnsignedLong(i6) << pickPos(56, 48)) 3745 | (toUnsignedLong(i7) << pickPos(56, 56))); 3746 } 3747 private static long makeLong(short i0, short i1, short i2, short i3) { 3748 return ((toUnsignedLong(i0) << pickPos(48, 0)) 3749 | (toUnsignedLong(i1) << pickPos(48, 16)) 3750 | (toUnsignedLong(i2) << pickPos(48, 32)) 3751 | (toUnsignedLong(i3) << pickPos(48, 48))); 3752 } 3753 private static long makeLong(int i0, int i1) { 3754 return (toUnsignedLong(i0) << pickPos(32, 0)) 3755 | (toUnsignedLong(i1) << pickPos(32, 32)); 3756 } 3757 private static int makeInt(short i0, short i1) { 3758 return (toUnsignedInt(i0) << pickPos(16, 0)) 3759 | (toUnsignedInt(i1) << pickPos(16, 16)); 3760 } 3761 private static int makeInt(byte i0, byte i1, byte i2, byte i3) { 3762 return ((toUnsignedInt(i0) << pickPos(24, 0)) 3763 | (toUnsignedInt(i1) << pickPos(24, 8)) 3764 | (toUnsignedInt(i2) << pickPos(24, 16)) 3765 | (toUnsignedInt(i3) << pickPos(24, 24))); 3766 } 3767 private static short makeShort(byte i0, byte i1) { 3768 return (short)((toUnsignedInt(i0) << pickPos(8, 0)) 3769 | (toUnsignedInt(i1) << pickPos(8, 8))); 3770 } 3771 3772 private static byte pick(byte le, byte be) { return BIG_ENDIAN ? be : le; } 3773 private static short pick(short le, short be) { return BIG_ENDIAN ? be : le; } 3774 private static int pick(int le, int be) { return BIG_ENDIAN ? be : le; } 3775 3776 // These methods write integers to memory from smaller parts 3777 // provided by their caller. The ordering in which these parts 3778 // are written is the native endianness of this platform. 3779 private void putLongParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3, byte i4, byte i5, byte i6, byte i7) { 3780 putByte(o, offset + 0, pick(i0, i7)); 3781 putByte(o, offset + 1, pick(i1, i6)); 3782 putByte(o, offset + 2, pick(i2, i5)); 3783 putByte(o, offset + 3, pick(i3, i4)); 3784 putByte(o, offset + 4, pick(i4, i3)); 3785 putByte(o, offset + 5, pick(i5, i2)); 3786 putByte(o, offset + 6, pick(i6, i1)); 3787 putByte(o, offset + 7, pick(i7, i0)); 3788 } 3789 private void putLongParts(Object o, long offset, short i0, short i1, short i2, short i3) { 3790 putShort(o, offset + 0, pick(i0, i3)); 3791 putShort(o, offset + 2, pick(i1, i2)); 3792 putShort(o, offset + 4, pick(i2, i1)); 3793 putShort(o, offset + 6, pick(i3, i0)); 3794 } 3795 private void putLongParts(Object o, long offset, int i0, int i1) { 3796 putInt(o, offset + 0, pick(i0, i1)); 3797 putInt(o, offset + 4, pick(i1, i0)); 3798 } 3799 private void putIntParts(Object o, long offset, short i0, short i1) { 3800 putShort(o, offset + 0, pick(i0, i1)); 3801 putShort(o, offset + 2, pick(i1, i0)); 3802 } 3803 private void putIntParts(Object o, long offset, byte i0, byte i1, byte i2, byte i3) { 3804 putByte(o, offset + 0, pick(i0, i3)); 3805 putByte(o, offset + 1, pick(i1, i2)); 3806 putByte(o, offset + 2, pick(i2, i1)); 3807 putByte(o, offset + 3, pick(i3, i0)); 3808 } 3809 private void putShortParts(Object o, long offset, byte i0, byte i1) { 3810 putByte(o, offset + 0, pick(i0, i1)); 3811 putByte(o, offset + 1, pick(i1, i0)); 3812 } 3813 3814 // Zero-extend an integer 3815 private static int toUnsignedInt(byte n) { return n & 0xff; } 3816 private static int toUnsignedInt(short n) { return n & 0xffff; } 3817 private static long toUnsignedLong(byte n) { return n & 0xffl; } 3818 private static long toUnsignedLong(short n) { return n & 0xffffl; } 3819 private static long toUnsignedLong(int n) { return n & 0xffffffffl; } 3820 3821 // Maybe byte-reverse an integer 3822 private static char convEndian(boolean big, char n) { return big == BIG_ENDIAN ? n : Character.reverseBytes(n); } 3823 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; } 3824 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; } 3825 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; } 3826 3827 3828 3829 private native long allocateMemory0(long bytes); 3830 private native long reallocateMemory0(long address, long bytes); 3831 private native void freeMemory0(long address); 3832 @IntrinsicCandidate 3833 private native void setMemory0(Object o, long offset, long bytes, byte value); 3834 @IntrinsicCandidate 3835 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes); 3836 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize); 3837 private native long objectFieldOffset0(Field f); 3838 private native long objectFieldOffset1(Class<?> c, String name); 3839 private native long staticFieldOffset0(Field f); 3840 private native Object staticFieldBase0(Field f); 3841 private native boolean shouldBeInitialized0(Class<?> c); 3842 private native void ensureClassInitialized0(Class<?> c); 3843 private native int arrayBaseOffset0(Class<?> arrayClass); 3844 private native int arrayIndexScale0(Class<?> arrayClass); 3845 private native int getLoadAverage0(double[] loadavg, int nelems); 3846 3847 3848 /** 3849 * Invokes the given direct byte buffer's cleaner, if any. 3850 * 3851 * @param directBuffer a direct byte buffer 3852 * @throws NullPointerException if {@code directBuffer} is null 3853 * @throws IllegalArgumentException if {@code directBuffer} is non-direct, 3854 * or is a {@link java.nio.Buffer#slice slice}, or is a 3855 * {@link java.nio.Buffer#duplicate duplicate} 3856 */ 3857 public void invokeCleaner(java.nio.ByteBuffer directBuffer) { 3858 if (!directBuffer.isDirect()) 3859 throw new IllegalArgumentException("buffer is non-direct"); 3860 3861 DirectBuffer db = (DirectBuffer) directBuffer; 3862 if (db.attachment() != null) 3863 throw new IllegalArgumentException("duplicate or slice"); 3864 3865 Cleaner cleaner = db.cleaner(); 3866 if (cleaner != null) { 3867 cleaner.clean(); 3868 } 3869 } 3870 }