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