8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.misc;
27
28 import jdk.internal.vm.annotation.AOTRuntimeSetup;
29 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
30 import jdk.internal.vm.annotation.ForceInline;
31 import jdk.internal.vm.annotation.IntrinsicCandidate;
32 import sun.nio.Cleaner;
33 import sun.nio.ch.DirectBuffer;
34
35 import java.lang.reflect.Field;
36 import java.security.ProtectionDomain;
37
38 import static jdk.internal.misc.UnsafeConstants.*;
39
40 /**
41 * A collection of methods for performing low-level, unsafe operations.
42 * Although the class and all methods are public, use of this class is
43 * limited because only trusted code can obtain instances of it.
44 *
45 * <em>Note:</em> It is the responsibility of the caller to make sure
46 * arguments are checked before methods of this class are
47 * called. While some rudimentary checks are performed on the input,
169 * The first two parameters are interpreted exactly as with
170 * {@link #getInt(Object, long)} to refer to a specific
171 * Java variable (field or array element). The given value
172 * is stored into that variable.
173 * <p>
174 * The variable must be of the same type as the method
175 * parameter {@code x}.
176 *
177 * @param o Java heap object in which the variable resides, if any, else
178 * null
179 * @param offset indication of where the variable resides in a Java heap
180 * object, if any, else a memory address locating the variable
181 * statically
182 * @param x the value to store into the indicated Java variable
183 * @throws RuntimeException No defined exceptions are thrown, not even
184 * {@link NullPointerException}
185 */
186 @IntrinsicCandidate
187 public native void putInt(Object o, long offset, int x);
188
189 /**
190 * Fetches a reference value from a given Java variable.
191 * @see #getInt(Object, long)
192 */
193 @IntrinsicCandidate
194 public native Object getReference(Object o, long offset);
195
196 /**
197 * Stores a reference value into a given Java variable.
198 * <p>
199 * Unless the reference {@code x} being stored is either null
200 * or matches the field type, the results are undefined.
201 * If the reference {@code o} is non-null, card marks or
202 * other store barriers for that object (if the VM requires them)
203 * are updated.
204 * @see #putInt(Object, long, int)
205 */
206 @IntrinsicCandidate
207 public native void putReference(Object o, long offset, Object x);
208
209 /** @see #getInt(Object, long) */
210 @IntrinsicCandidate
211 public native boolean getBoolean(Object o, long offset);
212
213 /** @see #putInt(Object, long, int) */
214 @IntrinsicCandidate
215 public native void putBoolean(Object o, long offset, boolean x);
216
217 /** @see #getInt(Object, long) */
218 @IntrinsicCandidate
219 public native byte getByte(Object o, long offset);
220
221 /** @see #putInt(Object, long, int) */
222 @IntrinsicCandidate
223 public native void putByte(Object o, long offset, byte x);
224
225 /** @see #getInt(Object, long) */
226 @IntrinsicCandidate
227 public native short getShort(Object o, long offset);
228
1178 }
1179
1180 /**
1181 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1182 * This is often needed in conjunction with obtaining the static field base
1183 * of a class.
1184 *
1185 * The call returns when either class {@code c} is fully initialized or
1186 * class {@code c} is being initialized and the call is performed from
1187 * the initializing thread. In the latter case a subsequent call to
1188 * {@link #shouldBeInitialized} will return {@code true}.
1189 */
1190 public void ensureClassInitialized(Class<?> c) {
1191 if (c == null) {
1192 throw new NullPointerException();
1193 }
1194
1195 ensureClassInitialized0(c);
1196 }
1197
1198 /**
1199 * Reports the offset of the first element in the storage allocation of a
1200 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1201 * for the same class, you may use that scale factor, together with this
1202 * base offset, to form new offsets to access elements of arrays of the
1203 * given class.
1204 * <p>
1205 * The return value is in the range of a {@code int}. The return type is
1206 * {@code long} to emphasize that long arithmetic should always be used
1207 * for offset calculations to avoid overflows.
1208 *
1209 * @see #getInt(Object, long)
1210 * @see #putInt(Object, long, int)
1211 */
1212 public long arrayBaseOffset(Class<?> arrayClass) {
1213 if (arrayClass == null) {
1214 throw new NullPointerException();
1215 }
1216
1217 return arrayBaseOffset0(arrayClass);
1218 }
1219
1220
1221 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1222 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1223 = theUnsafe.arrayBaseOffset(boolean[].class);
1224
1225 /** The value of {@code arrayBaseOffset(byte[].class)} */
1226 public static final long ARRAY_BYTE_BASE_OFFSET
1227 = theUnsafe.arrayBaseOffset(byte[].class);
1228
1229 /** The value of {@code arrayBaseOffset(short[].class)} */
1230 public static final long ARRAY_SHORT_BASE_OFFSET
1231 = theUnsafe.arrayBaseOffset(short[].class);
1232
1233 /** The value of {@code arrayBaseOffset(char[].class)} */
1234 public static final long ARRAY_CHAR_BASE_OFFSET
1235 = theUnsafe.arrayBaseOffset(char[].class);
1236
1237 /** The value of {@code arrayBaseOffset(int[].class)} */
1238 public static final long ARRAY_INT_BASE_OFFSET
1239 = theUnsafe.arrayBaseOffset(int[].class);
1246 public static final long ARRAY_FLOAT_BASE_OFFSET
1247 = theUnsafe.arrayBaseOffset(float[].class);
1248
1249 /** The value of {@code arrayBaseOffset(double[].class)} */
1250 public static final long ARRAY_DOUBLE_BASE_OFFSET
1251 = theUnsafe.arrayBaseOffset(double[].class);
1252
1253 /** The value of {@code arrayBaseOffset(Object[].class)} */
1254 public static final long ARRAY_OBJECT_BASE_OFFSET
1255 = theUnsafe.arrayBaseOffset(Object[].class);
1256
1257 /**
1258 * Reports the scale factor for addressing elements in the storage
1259 * allocation of a given array class. However, arrays of "narrow" types
1260 * will generally not work properly with accessors like {@link
1261 * #getByte(Object, long)}, so the scale factor for such classes is reported
1262 * as zero.
1263 * <p>
1264 * The computation of the actual memory offset should always use {@code
1265 * long} arithmetic to avoid overflows.
1266 *
1267 * @see #arrayBaseOffset
1268 * @see #getInt(Object, long)
1269 * @see #putInt(Object, long, int)
1270 */
1271 public int arrayIndexScale(Class<?> arrayClass) {
1272 if (arrayClass == null) {
1273 throw new NullPointerException();
1274 }
1275
1276 return arrayIndexScale0(arrayClass);
1277 }
1278
1279
1280 /** The value of {@code arrayIndexScale(boolean[].class)} */
1281 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1282 = theUnsafe.arrayIndexScale(boolean[].class);
1283
1284 /** The value of {@code arrayIndexScale(byte[].class)} */
1285 public static final int ARRAY_BYTE_INDEX_SCALE
1286 = theUnsafe.arrayIndexScale(byte[].class);
1287
1288 /** The value of {@code arrayIndexScale(short[].class)} */
1289 public static final int ARRAY_SHORT_INDEX_SCALE
1290 = theUnsafe.arrayIndexScale(short[].class);
1291
1292 /** The value of {@code arrayIndexScale(char[].class)} */
1293 public static final int ARRAY_CHAR_INDEX_SCALE
1294 = theUnsafe.arrayIndexScale(char[].class);
1295
1296 /** The value of {@code arrayIndexScale(int[].class)} */
1297 public static final int ARRAY_INT_INDEX_SCALE
1298 = theUnsafe.arrayIndexScale(int[].class);
1437 return null;
1438 }
1439
1440 /** Throws the exception without telling the verifier. */
1441 public native void throwException(Throwable ee);
1442
1443 /**
1444 * Atomically updates Java variable to {@code x} if it is currently
1445 * holding {@code expected}.
1446 *
1447 * <p>This operation has memory semantics of a {@code volatile} read
1448 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1449 *
1450 * @return {@code true} if successful
1451 */
1452 @IntrinsicCandidate
1453 public final native boolean compareAndSetReference(Object o, long offset,
1454 Object expected,
1455 Object x);
1456
1457 @IntrinsicCandidate
1458 public final native Object compareAndExchangeReference(Object o, long offset,
1459 Object expected,
1460 Object x);
1461
1462 @IntrinsicCandidate
1463 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1464 Object expected,
1465 Object x) {
1466 return compareAndExchangeReference(o, offset, expected, x);
1467 }
1468
1469 @IntrinsicCandidate
1470 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1471 Object expected,
1472 Object x) {
1473 return compareAndExchangeReference(o, offset, expected, x);
1474 }
1475
1476 @IntrinsicCandidate
1477 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1478 Object expected,
1479 Object x) {
1480 return compareAndSetReference(o, offset, expected, x);
1481 }
1482
1483 @IntrinsicCandidate
1484 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1485 Object expected,
1486 Object x) {
1487 return compareAndSetReference(o, offset, expected, x);
1488 }
1489
1490 @IntrinsicCandidate
1491 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1492 Object expected,
1493 Object x) {
1494 return compareAndSetReference(o, offset, expected, x);
1495 }
1496
1497 @IntrinsicCandidate
1498 public final boolean weakCompareAndSetReference(Object o, long offset,
1499 Object expected,
1500 Object x) {
1501 return compareAndSetReference(o, offset, expected, x);
1502 }
1503
1504 /**
1505 * Atomically updates Java variable to {@code x} if it is currently
1506 * holding {@code expected}.
1507 *
1508 * <p>This operation has memory semantics of a {@code volatile} read
1509 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1510 *
1511 * @return {@code true} if successful
1512 */
1513 @IntrinsicCandidate
1514 public final native boolean compareAndSetInt(Object o, long offset,
1515 int expected,
1516 int x);
1517
1518 @IntrinsicCandidate
1519 public final native int compareAndExchangeInt(Object o, long offset,
1520 int expected,
1521 int x);
1522
1523 @IntrinsicCandidate
2099 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2100 long expected,
2101 long x) {
2102 return compareAndSetLong(o, offset, expected, x);
2103 }
2104
2105 @IntrinsicCandidate
2106 public final boolean weakCompareAndSetLong(Object o, long offset,
2107 long expected,
2108 long x) {
2109 return compareAndSetLong(o, offset, expected, x);
2110 }
2111
2112 /**
2113 * Fetches a reference value from a given Java variable, with volatile
2114 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2115 */
2116 @IntrinsicCandidate
2117 public native Object getReferenceVolatile(Object o, long offset);
2118
2119 /**
2120 * Stores a reference value into a given Java variable, with
2121 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2122 */
2123 @IntrinsicCandidate
2124 public native void putReferenceVolatile(Object o, long offset, Object x);
2125
2126 /** Volatile version of {@link #getInt(Object, long)} */
2127 @IntrinsicCandidate
2128 public native int getIntVolatile(Object o, long offset);
2129
2130 /** Volatile version of {@link #putInt(Object, long, int)} */
2131 @IntrinsicCandidate
2132 public native void putIntVolatile(Object o, long offset, int x);
2133
2134 /** Volatile version of {@link #getBoolean(Object, long)} */
2135 @IntrinsicCandidate
2136 public native boolean getBooleanVolatile(Object o, long offset);
2137
2138 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2139 @IntrinsicCandidate
2140 public native void putBooleanVolatile(Object o, long offset, boolean x);
2141
2142 /** Volatile version of {@link #getByte(Object, long)} */
2143 @IntrinsicCandidate
2144 public native byte getByteVolatile(Object o, long offset);
2145
2178 /** Volatile version of {@link #putFloat(Object, long, float)} */
2179 @IntrinsicCandidate
2180 public native void putFloatVolatile(Object o, long offset, float x);
2181
2182 /** Volatile version of {@link #getDouble(Object, long)} */
2183 @IntrinsicCandidate
2184 public native double getDoubleVolatile(Object o, long offset);
2185
2186 /** Volatile version of {@link #putDouble(Object, long, double)} */
2187 @IntrinsicCandidate
2188 public native void putDoubleVolatile(Object o, long offset, double x);
2189
2190
2191
2192 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2193 @IntrinsicCandidate
2194 public final Object getReferenceAcquire(Object o, long offset) {
2195 return getReferenceVolatile(o, offset);
2196 }
2197
2198 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2199 @IntrinsicCandidate
2200 public final boolean getBooleanAcquire(Object o, long offset) {
2201 return getBooleanVolatile(o, offset);
2202 }
2203
2204 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2205 @IntrinsicCandidate
2206 public final byte getByteAcquire(Object o, long offset) {
2207 return getByteVolatile(o, offset);
2208 }
2209
2210 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2211 @IntrinsicCandidate
2212 public final short getShortAcquire(Object o, long offset) {
2213 return getShortVolatile(o, offset);
2214 }
2215
2216 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2217 @IntrinsicCandidate
2242 public final double getDoubleAcquire(Object o, long offset) {
2243 return getDoubleVolatile(o, offset);
2244 }
2245
2246 /*
2247 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2248 * that do not guarantee immediate visibility of the store to
2249 * other threads. This method is generally only useful if the
2250 * underlying field is a Java volatile (or if an array cell, one
2251 * that is otherwise only accessed using volatile accesses).
2252 *
2253 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2254 */
2255
2256 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2257 @IntrinsicCandidate
2258 public final void putReferenceRelease(Object o, long offset, Object x) {
2259 putReferenceVolatile(o, offset, x);
2260 }
2261
2262 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2263 @IntrinsicCandidate
2264 public final void putBooleanRelease(Object o, long offset, boolean x) {
2265 putBooleanVolatile(o, offset, x);
2266 }
2267
2268 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2269 @IntrinsicCandidate
2270 public final void putByteRelease(Object o, long offset, byte x) {
2271 putByteVolatile(o, offset, x);
2272 }
2273
2274 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2275 @IntrinsicCandidate
2276 public final void putShortRelease(Object o, long offset, short x) {
2277 putShortVolatile(o, offset, x);
2278 }
2279
2280 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2281 @IntrinsicCandidate
2298 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2299 @IntrinsicCandidate
2300 public final void putLongRelease(Object o, long offset, long x) {
2301 putLongVolatile(o, offset, x);
2302 }
2303
2304 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2305 @IntrinsicCandidate
2306 public final void putDoubleRelease(Object o, long offset, double x) {
2307 putDoubleVolatile(o, offset, x);
2308 }
2309
2310 // ------------------------------ Opaque --------------------------------------
2311
2312 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2313 @IntrinsicCandidate
2314 public final Object getReferenceOpaque(Object o, long offset) {
2315 return getReferenceVolatile(o, offset);
2316 }
2317
2318 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2319 @IntrinsicCandidate
2320 public final boolean getBooleanOpaque(Object o, long offset) {
2321 return getBooleanVolatile(o, offset);
2322 }
2323
2324 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2325 @IntrinsicCandidate
2326 public final byte getByteOpaque(Object o, long offset) {
2327 return getByteVolatile(o, offset);
2328 }
2329
2330 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2331 @IntrinsicCandidate
2332 public final short getShortOpaque(Object o, long offset) {
2333 return getShortVolatile(o, offset);
2334 }
2335
2336 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2337 @IntrinsicCandidate
2352 }
2353
2354 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2355 @IntrinsicCandidate
2356 public final long getLongOpaque(Object o, long offset) {
2357 return getLongVolatile(o, offset);
2358 }
2359
2360 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2361 @IntrinsicCandidate
2362 public final double getDoubleOpaque(Object o, long offset) {
2363 return getDoubleVolatile(o, offset);
2364 }
2365
2366 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2367 @IntrinsicCandidate
2368 public final void putReferenceOpaque(Object o, long offset, Object x) {
2369 putReferenceVolatile(o, offset, x);
2370 }
2371
2372 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2373 @IntrinsicCandidate
2374 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2375 putBooleanVolatile(o, offset, x);
2376 }
2377
2378 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2379 @IntrinsicCandidate
2380 public final void putByteOpaque(Object o, long offset, byte x) {
2381 putByteVolatile(o, offset, x);
2382 }
2383
2384 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2385 @IntrinsicCandidate
2386 public final void putShortOpaque(Object o, long offset, short x) {
2387 putShortVolatile(o, offset, x);
2388 }
2389
2390 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2391 @IntrinsicCandidate
2400 }
2401
2402 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2403 @IntrinsicCandidate
2404 public final void putFloatOpaque(Object o, long offset, float x) {
2405 putFloatVolatile(o, offset, x);
2406 }
2407
2408 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2409 @IntrinsicCandidate
2410 public final void putLongOpaque(Object o, long offset, long x) {
2411 putLongVolatile(o, offset, x);
2412 }
2413
2414 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2415 @IntrinsicCandidate
2416 public final void putDoubleOpaque(Object o, long offset, double x) {
2417 putDoubleVolatile(o, offset, x);
2418 }
2419
2420 /**
2421 * Unblocks the given thread blocked on {@code park}, or, if it is
2422 * not blocked, causes the subsequent call to {@code park} not to
2423 * block. Note: this operation is "unsafe" solely because the
2424 * caller must somehow ensure that the thread has not been
2425 * destroyed. Nothing special is usually required to ensure this
2426 * when called from Java (in which there will ordinarily be a live
2427 * reference to the thread) but this is not nearly-automatically
2428 * so when calling from native code.
2429 *
2430 * @param thread the thread to unpark.
2431 */
2432 @IntrinsicCandidate
2433 public native void unpark(Object thread);
2434
2435 /**
2436 * Blocks current thread, returning when a balancing
2437 * {@code unpark} occurs, or a balancing {@code unpark} has
2438 * already occurred, or the thread is interrupted, or, if not
2439 * absolute and time is not zero, the given time nanoseconds have
2786 /**
2787 * Atomically exchanges the given reference value with the current
2788 * reference value of a field or array element within the given
2789 * object {@code o} at the given {@code offset}.
2790 *
2791 * @param o object/array to update the field/element in
2792 * @param offset field/element offset
2793 * @param newValue new value
2794 * @return the previous value
2795 * @since 1.8
2796 */
2797 @IntrinsicCandidate
2798 public final Object getAndSetReference(Object o, long offset, Object newValue) {
2799 Object v;
2800 do {
2801 v = getReferenceVolatile(o, offset);
2802 } while (!weakCompareAndSetReference(o, offset, v, newValue));
2803 return v;
2804 }
2805
2806 @ForceInline
2807 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
2808 Object v;
2809 do {
2810 v = getReference(o, offset);
2811 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
2812 return v;
2813 }
2814
2815 @ForceInline
2816 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
2817 Object v;
2818 do {
2819 v = getReferenceAcquire(o, offset);
2820 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
2821 return v;
2822 }
2823
2824 @IntrinsicCandidate
2825 public final byte getAndSetByte(Object o, long offset, byte newValue) {
2826 byte v;
2827 do {
2828 v = getByteVolatile(o, offset);
2829 } while (!weakCompareAndSetByte(o, offset, v, newValue));
2830 return v;
2831 }
2832
2833 @ForceInline
2834 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
2835 byte v;
2836 do {
2837 v = getByte(o, offset);
2838 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
2839 return v;
2840 }
2841
2842 @ForceInline
2843 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
3859 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
3860 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
3861 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
3862
3863
3864
3865 private native long allocateMemory0(long bytes);
3866 private native long reallocateMemory0(long address, long bytes);
3867 private native void freeMemory0(long address);
3868 @IntrinsicCandidate
3869 private native void setMemory0(Object o, long offset, long bytes, byte value);
3870 @IntrinsicCandidate
3871 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
3872 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
3873 private native long objectFieldOffset0(Field f); // throws IAE
3874 private native long knownObjectFieldOffset0(Class<?> c, String name); // error code: -1 not found, -2 static
3875 private native long staticFieldOffset0(Field f); // throws IAE
3876 private native Object staticFieldBase0(Field f); // throws IAE
3877 private native boolean shouldBeInitialized0(Class<?> c);
3878 private native void ensureClassInitialized0(Class<?> c);
3879 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
3880 private native int arrayIndexScale0(Class<?> arrayClass);
3881 private native int getLoadAverage0(double[] loadavg, int nelems);
3882
3883
3884 /**
3885 * Invokes the given direct byte buffer's cleaner, if any.
3886 *
3887 * @param directBuffer a direct byte buffer
3888 * @throws NullPointerException if {@code directBuffer} is null
3889 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
3890 * or is a {@link java.nio.Buffer#slice slice}, or is a
3891 * {@link java.nio.Buffer#duplicate duplicate}
3892 */
3893 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
3894 if (!directBuffer.isDirect())
3895 throw new IllegalArgumentException("buffer is non-direct");
3896
3897 DirectBuffer db = (DirectBuffer) directBuffer;
3898 if (db.attachment() != null)
3899 throw new IllegalArgumentException("duplicate or slice");
3900
3901 Cleaner cleaner = db.cleaner();
|
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.internal.misc;
27
28 import jdk.internal.value.ValueClass;
29 import jdk.internal.vm.annotation.AOTRuntimeSetup;
30 import jdk.internal.vm.annotation.AOTSafeClassInitializer;
31 import jdk.internal.vm.annotation.ForceInline;
32 import jdk.internal.vm.annotation.IntrinsicCandidate;
33 import sun.nio.Cleaner;
34 import sun.nio.ch.DirectBuffer;
35
36 import java.lang.reflect.Field;
37 import java.security.ProtectionDomain;
38
39 import static jdk.internal.misc.UnsafeConstants.*;
40
41 /**
42 * A collection of methods for performing low-level, unsafe operations.
43 * Although the class and all methods are public, use of this class is
44 * limited because only trusted code can obtain instances of it.
45 *
46 * <em>Note:</em> It is the responsibility of the caller to make sure
47 * arguments are checked before methods of this class are
48 * called. While some rudimentary checks are performed on the input,
170 * The first two parameters are interpreted exactly as with
171 * {@link #getInt(Object, long)} to refer to a specific
172 * Java variable (field or array element). The given value
173 * is stored into that variable.
174 * <p>
175 * The variable must be of the same type as the method
176 * parameter {@code x}.
177 *
178 * @param o Java heap object in which the variable resides, if any, else
179 * null
180 * @param offset indication of where the variable resides in a Java heap
181 * object, if any, else a memory address locating the variable
182 * statically
183 * @param x the value to store into the indicated Java variable
184 * @throws RuntimeException No defined exceptions are thrown, not even
185 * {@link NullPointerException}
186 */
187 @IntrinsicCandidate
188 public native void putInt(Object o, long offset, int x);
189
190
191 /**
192 * Returns true if the given field is flattened.
193 */
194 public boolean isFlatField(Field f) {
195 if (f == null) {
196 throw new NullPointerException();
197 }
198 return isFlatField0(f);
199 }
200
201 private native boolean isFlatField0(Object o);
202
203 /* Returns true if the given field has a null marker
204 * <p>
205 * Nullable flat fields are stored in a flattened representation
206 * and have an associated null marker to indicate if the the field value is
207 * null or the one stored with the flat representation
208 */
209
210 public boolean hasNullMarker(Field f) {
211 if (f == null) {
212 throw new NullPointerException();
213 }
214 return hasNullMarker0(f);
215 }
216
217 private native boolean hasNullMarker0(Object o);
218
219 /* Returns the offset of the null marker of the field,
220 * or -1 if the field doesn't have a null marker
221 */
222
223 public int nullMarkerOffset(Field f) {
224 if (f == null) {
225 throw new NullPointerException();
226 }
227 return nullMarkerOffset0(f);
228 }
229
230 private native int nullMarkerOffset0(Object o);
231
232 public static final int NON_FLAT_LAYOUT = 0;
233
234 /* Reports the kind of layout used for an element in the storage
235 * allocation of the given array. Do not expect to perform any logic
236 * or layout control with this value, it is just an opaque token
237 * used for performance reasons.
238 *
239 * A layout of 0 indicates this array is not flat.
240 */
241 public int arrayLayout(Object[] array) {
242 if (array == null) {
243 throw new NullPointerException();
244 }
245 return arrayLayout0(array);
246 }
247
248 @IntrinsicCandidate
249 private native int arrayLayout0(Object[] array);
250
251
252 /* Reports the kind of layout used for a given field in the storage
253 * allocation of its class. Do not expect to perform any logic
254 * or layout control with this value, it is just an opaque token
255 * used for performance reasons.
256 *
257 * A layout of 0 indicates this field is not flat.
258 */
259 public int fieldLayout(Field f) {
260 if (f == null) {
261 throw new NullPointerException();
262 }
263 return fieldLayout0(f);
264 }
265
266 private native int fieldLayout0(Object o);
267
268 public native Object[] newSpecialArray(Class<?> componentType,
269 int length, int layoutKind);
270
271 /**
272 * Fetches a reference value from a given Java variable.
273 * This method can return a reference to either an object or value
274 * or a null reference.
275 *
276 * @see #getInt(Object, long)
277 */
278 @IntrinsicCandidate
279 public native Object getReference(Object o, long offset);
280
281 /**
282 * Stores a reference value into a given Java variable.
283 * This method can store a reference to either an object or value
284 * or a null reference.
285 * <p>
286 * Unless the reference {@code x} being stored is either null
287 * or matches the field type, the results are undefined.
288 * If the reference {@code o} is non-null, card marks or
289 * other store barriers for that object (if the VM requires them)
290 * are updated.
291 * @see #putInt(Object, long, int)
292 */
293 @IntrinsicCandidate
294 public native void putReference(Object o, long offset, Object x);
295
296 /**
297 * Fetches a value of type {@code <V>} from a given Java variable.
298 * More specifically, fetches a field or array element within the given
299 * {@code o} object at the given offset, or (if {@code o} is null)
300 * from the memory address whose numerical value is the given offset.
301 *
302 * @apiNote
303 * The returned object is newly allocated into the heap, because flat
304 * values lack object headers and thus can't be used as objects directly.
305 *
306 * @param o Java heap object in which the variable resides, if any, else
307 * null
308 * @param offset indication of where the variable resides in a Java heap
309 * object, if any, else a memory address locating the variable
310 * statically
311 * @param layoutKind opaque value used by the VM to know the layout
312 * the field or array element. This value must be retrieved with
313 * {@link #fieldLayout} or {@link #arrayLayout}.
314 * @param valueType value type
315 * @param <V> the type of a value
316 * @return the value fetched from the indicated Java variable
317 * @throws RuntimeException No defined exceptions are thrown, not even
318 * {@link NullPointerException}
319 */
320 @IntrinsicCandidate
321 public native <V> V getFlatValue(Object o, long offset, int layoutKind, Class<?> valueType);
322
323 /**
324 * Stores the given value into a given Java variable.
325 *
326 * Unless the reference {@code o} being stored is either null
327 * or matches the field type, the results are undefined.
328 *
329 * @param o Java heap object in which the variable resides, if any, else
330 * null
331 * @param offset indication of where the variable resides in a Java heap
332 * object, if any, else a memory address locating the variable
333 * statically
334 * @param layoutKind opaque value used by the VM to know the layout
335 * the field or array element. This value must be retrieved with
336 * {@link #fieldLayout} or {@link #arrayLayout}.
337 * @param valueType value type
338 * @param v the value to store into the indicated Java variable
339 * @param <V> the type of a value
340 * @throws RuntimeException No defined exceptions are thrown, not even
341 * {@link NullPointerException}
342 */
343 @IntrinsicCandidate
344 public native <V> void putFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, V v);
345
346 /**
347 * Returns an object instance with a private buffered value whose layout
348 * and contents is exactly the given value instance. The return object
349 * is in the larval state that can be updated using the unsafe put operation.
350 *
351 * @param value a value instance
352 * @param <V> the type of the given value instance
353 */
354 @IntrinsicCandidate
355 public native <V> V makePrivateBuffer(V value);
356
357 /**
358 * Exits the larval state and returns a value instance.
359 *
360 * @param value a value instance
361 * @param <V> the type of the given value instance
362 */
363 @IntrinsicCandidate
364 public native <V> V finishPrivateBuffer(V value);
365
366 /**
367 * Returns the header size of the given value type.
368 *
369 * @param valueType value type
370 * @return the header size of the value type
371 */
372 public native <V> long valueHeaderSize(Class<V> valueType);
373
374 /** @see #getInt(Object, long) */
375 @IntrinsicCandidate
376 public native boolean getBoolean(Object o, long offset);
377
378 /** @see #putInt(Object, long, int) */
379 @IntrinsicCandidate
380 public native void putBoolean(Object o, long offset, boolean x);
381
382 /** @see #getInt(Object, long) */
383 @IntrinsicCandidate
384 public native byte getByte(Object o, long offset);
385
386 /** @see #putInt(Object, long, int) */
387 @IntrinsicCandidate
388 public native void putByte(Object o, long offset, byte x);
389
390 /** @see #getInt(Object, long) */
391 @IntrinsicCandidate
392 public native short getShort(Object o, long offset);
393
1343 }
1344
1345 /**
1346 * Ensures the given class has been initialized (see JVMS-5.5 for details).
1347 * This is often needed in conjunction with obtaining the static field base
1348 * of a class.
1349 *
1350 * The call returns when either class {@code c} is fully initialized or
1351 * class {@code c} is being initialized and the call is performed from
1352 * the initializing thread. In the latter case a subsequent call to
1353 * {@link #shouldBeInitialized} will return {@code true}.
1354 */
1355 public void ensureClassInitialized(Class<?> c) {
1356 if (c == null) {
1357 throw new NullPointerException();
1358 }
1359
1360 ensureClassInitialized0(c);
1361 }
1362
1363 /**
1364 * The reading or writing of strict static fields may require
1365 * special processing. Notify the VM that such an event is about
1366 * to happen. The VM may respond by throwing an exception, in the
1367 * case of a read of an uninitialized field. If the VM allows the
1368 * method to return normally, no further calls are needed, with
1369 * the same arguments.
1370 */
1371 public void notifyStrictStaticAccess(Class<?> c, long staticFieldOffset, boolean writing) {
1372 if (c == null) {
1373 throw new NullPointerException();
1374 }
1375 notifyStrictStaticAccess0(c, staticFieldOffset, writing);
1376 }
1377
1378 /**
1379 * Reports the offset of the first element in the storage allocation of a
1380 * given array class. If {@link #arrayIndexScale} returns a non-zero value
1381 * for the same class, you may use that scale factor, together with this
1382 * base offset, to form new offsets to access elements of arrays of the
1383 * given class.
1384 * <p>
1385 * The return value is in the range of a {@code int}. The return type is
1386 * {@code long} to emphasize that long arithmetic should always be used
1387 * for offset calculations to avoid overflows.
1388 * <p>
1389 * This method doesn't support arrays with an element type that is
1390 * a value class, because this type of array can have multiple layouts.
1391 * For these arrays, {@code arrayInstanceBaseOffset(Object[] array)}
1392 * must be used instead.
1393 *
1394 * @see #getInt(Object, long)
1395 * @see #putInt(Object, long, int)
1396 */
1397 public long arrayBaseOffset(Class<?> arrayClass) {
1398 if (arrayClass == null) {
1399 throw new NullPointerException();
1400 }
1401
1402 return arrayBaseOffset0(arrayClass);
1403 }
1404
1405 public long arrayInstanceBaseOffset(Object[] array) {
1406 if (array == null) {
1407 throw new NullPointerException();
1408 }
1409
1410 return arrayInstanceBaseOffset0(array);
1411 }
1412
1413 /** The value of {@code arrayBaseOffset(boolean[].class)} */
1414 public static final long ARRAY_BOOLEAN_BASE_OFFSET
1415 = theUnsafe.arrayBaseOffset(boolean[].class);
1416
1417 /** The value of {@code arrayBaseOffset(byte[].class)} */
1418 public static final long ARRAY_BYTE_BASE_OFFSET
1419 = theUnsafe.arrayBaseOffset(byte[].class);
1420
1421 /** The value of {@code arrayBaseOffset(short[].class)} */
1422 public static final long ARRAY_SHORT_BASE_OFFSET
1423 = theUnsafe.arrayBaseOffset(short[].class);
1424
1425 /** The value of {@code arrayBaseOffset(char[].class)} */
1426 public static final long ARRAY_CHAR_BASE_OFFSET
1427 = theUnsafe.arrayBaseOffset(char[].class);
1428
1429 /** The value of {@code arrayBaseOffset(int[].class)} */
1430 public static final long ARRAY_INT_BASE_OFFSET
1431 = theUnsafe.arrayBaseOffset(int[].class);
1438 public static final long ARRAY_FLOAT_BASE_OFFSET
1439 = theUnsafe.arrayBaseOffset(float[].class);
1440
1441 /** The value of {@code arrayBaseOffset(double[].class)} */
1442 public static final long ARRAY_DOUBLE_BASE_OFFSET
1443 = theUnsafe.arrayBaseOffset(double[].class);
1444
1445 /** The value of {@code arrayBaseOffset(Object[].class)} */
1446 public static final long ARRAY_OBJECT_BASE_OFFSET
1447 = theUnsafe.arrayBaseOffset(Object[].class);
1448
1449 /**
1450 * Reports the scale factor for addressing elements in the storage
1451 * allocation of a given array class. However, arrays of "narrow" types
1452 * will generally not work properly with accessors like {@link
1453 * #getByte(Object, long)}, so the scale factor for such classes is reported
1454 * as zero.
1455 * <p>
1456 * The computation of the actual memory offset should always use {@code
1457 * long} arithmetic to avoid overflows.
1458 * <p>
1459 * This method doesn't support arrays with an element type that is
1460 * a value class, because this type of array can have multiple layouts.
1461 * For these arrays, {@code arrayInstanceIndexScale(Object[] array)}
1462 * must be used instead.
1463 *
1464 * @see #arrayBaseOffset
1465 * @see #getInt(Object, long)
1466 * @see #putInt(Object, long, int)
1467 */
1468 public int arrayIndexScale(Class<?> arrayClass) {
1469 if (arrayClass == null) {
1470 throw new NullPointerException();
1471 }
1472
1473 return arrayIndexScale0(arrayClass);
1474 }
1475
1476 public int arrayInstanceIndexScale(Object[] array) {
1477 if (array == null) {
1478 throw new NullPointerException();
1479 }
1480
1481 return arrayInstanceIndexScale0(array);
1482 }
1483
1484 public int[] getFieldMap(Class<? extends Object> c) {
1485 if (c == null) {
1486 throw new NullPointerException();
1487 }
1488 return getFieldMap0(c);
1489 }
1490
1491 /**
1492 * Return the size of the object in the heap.
1493 * @param o an object
1494 * @return the objects's size
1495 * @since Valhalla
1496 */
1497 public long getObjectSize(Object o) {
1498 if (o == null)
1499 throw new NullPointerException();
1500 return getObjectSize0(o);
1501 }
1502
1503 /** The value of {@code arrayIndexScale(boolean[].class)} */
1504 public static final int ARRAY_BOOLEAN_INDEX_SCALE
1505 = theUnsafe.arrayIndexScale(boolean[].class);
1506
1507 /** The value of {@code arrayIndexScale(byte[].class)} */
1508 public static final int ARRAY_BYTE_INDEX_SCALE
1509 = theUnsafe.arrayIndexScale(byte[].class);
1510
1511 /** The value of {@code arrayIndexScale(short[].class)} */
1512 public static final int ARRAY_SHORT_INDEX_SCALE
1513 = theUnsafe.arrayIndexScale(short[].class);
1514
1515 /** The value of {@code arrayIndexScale(char[].class)} */
1516 public static final int ARRAY_CHAR_INDEX_SCALE
1517 = theUnsafe.arrayIndexScale(char[].class);
1518
1519 /** The value of {@code arrayIndexScale(int[].class)} */
1520 public static final int ARRAY_INT_INDEX_SCALE
1521 = theUnsafe.arrayIndexScale(int[].class);
1660 return null;
1661 }
1662
1663 /** Throws the exception without telling the verifier. */
1664 public native void throwException(Throwable ee);
1665
1666 /**
1667 * Atomically updates Java variable to {@code x} if it is currently
1668 * holding {@code expected}.
1669 *
1670 * <p>This operation has memory semantics of a {@code volatile} read
1671 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1672 *
1673 * @return {@code true} if successful
1674 */
1675 @IntrinsicCandidate
1676 public final native boolean compareAndSetReference(Object o, long offset,
1677 Object expected,
1678 Object x);
1679
1680 private final boolean isValueObject(Object o) {
1681 return o != null && o.getClass().isValue();
1682 }
1683
1684 /*
1685 * For value type, CAS should do substitutability test as opposed
1686 * to two pointers comparison.
1687 */
1688 @ForceInline
1689 public final <V> boolean compareAndSetReference(Object o, long offset,
1690 Class<?> type,
1691 V expected,
1692 V x) {
1693 if (type.isValue() || isValueObject(expected)) {
1694 while (true) {
1695 Object witness = getReferenceVolatile(o, offset);
1696 if (witness != expected) {
1697 return false;
1698 }
1699 if (compareAndSetReference(o, offset, witness, x)) {
1700 return true;
1701 }
1702 }
1703 } else {
1704 return compareAndSetReference(o, offset, expected, x);
1705 }
1706 }
1707
1708 @ForceInline
1709 public final <V> boolean compareAndSetFlatValue(Object o, long offset,
1710 int layout,
1711 Class<?> valueType,
1712 V expected,
1713 V x) {
1714 while (true) {
1715 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1716 if (witness != expected) {
1717 return false;
1718 }
1719 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1720 return true;
1721 }
1722 }
1723 }
1724
1725 @IntrinsicCandidate
1726 public final native Object compareAndExchangeReference(Object o, long offset,
1727 Object expected,
1728 Object x);
1729
1730 @ForceInline
1731 public final <V> Object compareAndExchangeReference(Object o, long offset,
1732 Class<?> valueType,
1733 V expected,
1734 V x) {
1735 if (valueType.isValue() || isValueObject(expected)) {
1736 while (true) {
1737 Object witness = getReferenceVolatile(o, offset);
1738 if (witness != expected) {
1739 return witness;
1740 }
1741 if (compareAndSetReference(o, offset, witness, x)) {
1742 return witness;
1743 }
1744 }
1745 } else {
1746 return compareAndExchangeReference(o, offset, expected, x);
1747 }
1748 }
1749
1750 @ForceInline
1751 public final <V> Object compareAndExchangeFlatValue(Object o, long offset,
1752 int layout,
1753 Class<?> valueType,
1754 V expected,
1755 V x) {
1756 while (true) {
1757 Object witness = getFlatValueVolatile(o, offset, layout, valueType);
1758 if (witness != expected) {
1759 return witness;
1760 }
1761 if (compareAndSetFlatValueAsBytes(o, offset, layout, valueType, witness, x)) {
1762 return witness;
1763 }
1764 }
1765 }
1766
1767 @IntrinsicCandidate
1768 public final Object compareAndExchangeReferenceAcquire(Object o, long offset,
1769 Object expected,
1770 Object x) {
1771 return compareAndExchangeReference(o, offset, expected, x);
1772 }
1773
1774 public final <V> Object compareAndExchangeReferenceAcquire(Object o, long offset,
1775 Class<?> valueType,
1776 V expected,
1777 V x) {
1778 return compareAndExchangeReference(o, offset, valueType, expected, x);
1779 }
1780
1781 @ForceInline
1782 public final <V> Object compareAndExchangeFlatValueAcquire(Object o, long offset,
1783 int layout,
1784 Class<?> valueType,
1785 V expected,
1786 V x) {
1787 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1788 }
1789
1790 @IntrinsicCandidate
1791 public final Object compareAndExchangeReferenceRelease(Object o, long offset,
1792 Object expected,
1793 Object x) {
1794 return compareAndExchangeReference(o, offset, expected, x);
1795 }
1796
1797 public final <V> Object compareAndExchangeReferenceRelease(Object o, long offset,
1798 Class<?> valueType,
1799 V expected,
1800 V x) {
1801 return compareAndExchangeReference(o, offset, valueType, expected, x);
1802 }
1803
1804 @ForceInline
1805 public final <V> Object compareAndExchangeFlatValueRelease(Object o, long offset,
1806 int layout,
1807 Class<?> valueType,
1808 V expected,
1809 V x) {
1810 return compareAndExchangeFlatValue(o, offset, layout, valueType, expected, x);
1811 }
1812
1813 @IntrinsicCandidate
1814 public final boolean weakCompareAndSetReferencePlain(Object o, long offset,
1815 Object expected,
1816 Object x) {
1817 return compareAndSetReference(o, offset, expected, x);
1818 }
1819
1820 public final <V> boolean weakCompareAndSetReferencePlain(Object o, long offset,
1821 Class<?> valueType,
1822 V expected,
1823 V x) {
1824 if (valueType.isValue() || isValueObject(expected)) {
1825 return compareAndSetReference(o, offset, valueType, expected, x);
1826 } else {
1827 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1828 }
1829 }
1830
1831 @ForceInline
1832 public final <V> boolean weakCompareAndSetFlatValuePlain(Object o, long offset,
1833 int layout,
1834 Class<?> valueType,
1835 V expected,
1836 V x) {
1837 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1838 }
1839
1840 @IntrinsicCandidate
1841 public final boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1842 Object expected,
1843 Object x) {
1844 return compareAndSetReference(o, offset, expected, x);
1845 }
1846
1847 public final <V> boolean weakCompareAndSetReferenceAcquire(Object o, long offset,
1848 Class<?> valueType,
1849 V expected,
1850 V x) {
1851 if (valueType.isValue() || isValueObject(expected)) {
1852 return compareAndSetReference(o, offset, valueType, expected, x);
1853 } else {
1854 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1855 }
1856 }
1857
1858 @ForceInline
1859 public final <V> boolean weakCompareAndSetFlatValueAcquire(Object o, long offset,
1860 int layout,
1861 Class<?> valueType,
1862 V expected,
1863 V x) {
1864 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1865 }
1866
1867 @IntrinsicCandidate
1868 public final boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1869 Object expected,
1870 Object x) {
1871 return compareAndSetReference(o, offset, expected, x);
1872 }
1873
1874 public final <V> boolean weakCompareAndSetReferenceRelease(Object o, long offset,
1875 Class<?> valueType,
1876 V expected,
1877 V x) {
1878 if (valueType.isValue() || isValueObject(expected)) {
1879 return compareAndSetReference(o, offset, valueType, expected, x);
1880 } else {
1881 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1882 }
1883 }
1884
1885 @ForceInline
1886 public final <V> boolean weakCompareAndSetFlatValueRelease(Object o, long offset,
1887 int layout,
1888 Class<?> valueType,
1889 V expected,
1890 V x) {
1891 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1892 }
1893
1894 @IntrinsicCandidate
1895 public final boolean weakCompareAndSetReference(Object o, long offset,
1896 Object expected,
1897 Object x) {
1898 return compareAndSetReference(o, offset, expected, x);
1899 }
1900
1901 public final <V> boolean weakCompareAndSetReference(Object o, long offset,
1902 Class<?> valueType,
1903 V expected,
1904 V x) {
1905 if (valueType.isValue() || isValueObject(expected)) {
1906 return compareAndSetReference(o, offset, valueType, expected, x);
1907 } else {
1908 return weakCompareAndSetReferencePlain(o, offset, expected, x);
1909 }
1910 }
1911
1912 @ForceInline
1913 public final <V> boolean weakCompareAndSetFlatValue(Object o, long offset,
1914 int layout,
1915 Class<?> valueType,
1916 V expected,
1917 V x) {
1918 return compareAndSetFlatValue(o, offset, layout, valueType, expected, x);
1919 }
1920
1921 /**
1922 * Atomically updates Java variable to {@code x} if it is currently
1923 * holding {@code expected}.
1924 *
1925 * <p>This operation has memory semantics of a {@code volatile} read
1926 * and write. Corresponds to C11 atomic_compare_exchange_strong.
1927 *
1928 * @return {@code true} if successful
1929 */
1930 @IntrinsicCandidate
1931 public final native boolean compareAndSetInt(Object o, long offset,
1932 int expected,
1933 int x);
1934
1935 @IntrinsicCandidate
1936 public final native int compareAndExchangeInt(Object o, long offset,
1937 int expected,
1938 int x);
1939
1940 @IntrinsicCandidate
2516 public final boolean weakCompareAndSetLongRelease(Object o, long offset,
2517 long expected,
2518 long x) {
2519 return compareAndSetLong(o, offset, expected, x);
2520 }
2521
2522 @IntrinsicCandidate
2523 public final boolean weakCompareAndSetLong(Object o, long offset,
2524 long expected,
2525 long x) {
2526 return compareAndSetLong(o, offset, expected, x);
2527 }
2528
2529 /**
2530 * Fetches a reference value from a given Java variable, with volatile
2531 * load semantics. Otherwise identical to {@link #getReference(Object, long)}
2532 */
2533 @IntrinsicCandidate
2534 public native Object getReferenceVolatile(Object o, long offset);
2535
2536 @ForceInline
2537 public final <V> Object getFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType) {
2538 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2539 Object res = getFlatValue(o, offset, layout, valueType);
2540 fullFence();
2541 return res;
2542 }
2543
2544 /**
2545 * Stores a reference value into a given Java variable, with
2546 * volatile store semantics. Otherwise identical to {@link #putReference(Object, long, Object)}
2547 */
2548 @IntrinsicCandidate
2549 public native void putReferenceVolatile(Object o, long offset, Object x);
2550
2551 @ForceInline
2552 public final <V> void putFlatValueVolatile(Object o, long offset, int layout, Class<?> valueType, V x) {
2553 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2554 putFlatValueRelease(o, offset, layout, valueType, x);
2555 fullFence();
2556 }
2557
2558 /** Volatile version of {@link #getInt(Object, long)} */
2559 @IntrinsicCandidate
2560 public native int getIntVolatile(Object o, long offset);
2561
2562 /** Volatile version of {@link #putInt(Object, long, int)} */
2563 @IntrinsicCandidate
2564 public native void putIntVolatile(Object o, long offset, int x);
2565
2566 /** Volatile version of {@link #getBoolean(Object, long)} */
2567 @IntrinsicCandidate
2568 public native boolean getBooleanVolatile(Object o, long offset);
2569
2570 /** Volatile version of {@link #putBoolean(Object, long, boolean)} */
2571 @IntrinsicCandidate
2572 public native void putBooleanVolatile(Object o, long offset, boolean x);
2573
2574 /** Volatile version of {@link #getByte(Object, long)} */
2575 @IntrinsicCandidate
2576 public native byte getByteVolatile(Object o, long offset);
2577
2610 /** Volatile version of {@link #putFloat(Object, long, float)} */
2611 @IntrinsicCandidate
2612 public native void putFloatVolatile(Object o, long offset, float x);
2613
2614 /** Volatile version of {@link #getDouble(Object, long)} */
2615 @IntrinsicCandidate
2616 public native double getDoubleVolatile(Object o, long offset);
2617
2618 /** Volatile version of {@link #putDouble(Object, long, double)} */
2619 @IntrinsicCandidate
2620 public native void putDoubleVolatile(Object o, long offset, double x);
2621
2622
2623
2624 /** Acquire version of {@link #getReferenceVolatile(Object, long)} */
2625 @IntrinsicCandidate
2626 public final Object getReferenceAcquire(Object o, long offset) {
2627 return getReferenceVolatile(o, offset);
2628 }
2629
2630 @ForceInline
2631 public final <V> Object getFlatValueAcquire(Object o, long offset, int layout, Class<?> valueType) {
2632 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2633 Object res = getFlatValue(o, offset, layout, valueType);
2634 loadFence();
2635 return res;
2636 }
2637
2638 /** Acquire version of {@link #getBooleanVolatile(Object, long)} */
2639 @IntrinsicCandidate
2640 public final boolean getBooleanAcquire(Object o, long offset) {
2641 return getBooleanVolatile(o, offset);
2642 }
2643
2644 /** Acquire version of {@link #getByteVolatile(Object, long)} */
2645 @IntrinsicCandidate
2646 public final byte getByteAcquire(Object o, long offset) {
2647 return getByteVolatile(o, offset);
2648 }
2649
2650 /** Acquire version of {@link #getShortVolatile(Object, long)} */
2651 @IntrinsicCandidate
2652 public final short getShortAcquire(Object o, long offset) {
2653 return getShortVolatile(o, offset);
2654 }
2655
2656 /** Acquire version of {@link #getCharVolatile(Object, long)} */
2657 @IntrinsicCandidate
2682 public final double getDoubleAcquire(Object o, long offset) {
2683 return getDoubleVolatile(o, offset);
2684 }
2685
2686 /*
2687 * Versions of {@link #putReferenceVolatile(Object, long, Object)}
2688 * that do not guarantee immediate visibility of the store to
2689 * other threads. This method is generally only useful if the
2690 * underlying field is a Java volatile (or if an array cell, one
2691 * that is otherwise only accessed using volatile accesses).
2692 *
2693 * Corresponds to C11 atomic_store_explicit(..., memory_order_release).
2694 */
2695
2696 /** Release version of {@link #putReferenceVolatile(Object, long, Object)} */
2697 @IntrinsicCandidate
2698 public final void putReferenceRelease(Object o, long offset, Object x) {
2699 putReferenceVolatile(o, offset, x);
2700 }
2701
2702 @ForceInline
2703 public final <V> void putFlatValueRelease(Object o, long offset, int layout, Class<?> valueType, V x) {
2704 // we translate using fences (see: https://gee.cs.oswego.edu/dl/html/j9mm.html)
2705 storeFence();
2706 putFlatValue(o, offset, layout, valueType, x);
2707 }
2708
2709 /** Release version of {@link #putBooleanVolatile(Object, long, boolean)} */
2710 @IntrinsicCandidate
2711 public final void putBooleanRelease(Object o, long offset, boolean x) {
2712 putBooleanVolatile(o, offset, x);
2713 }
2714
2715 /** Release version of {@link #putByteVolatile(Object, long, byte)} */
2716 @IntrinsicCandidate
2717 public final void putByteRelease(Object o, long offset, byte x) {
2718 putByteVolatile(o, offset, x);
2719 }
2720
2721 /** Release version of {@link #putShortVolatile(Object, long, short)} */
2722 @IntrinsicCandidate
2723 public final void putShortRelease(Object o, long offset, short x) {
2724 putShortVolatile(o, offset, x);
2725 }
2726
2727 /** Release version of {@link #putCharVolatile(Object, long, char)} */
2728 @IntrinsicCandidate
2745 /** Release version of {@link #putLongVolatile(Object, long, long)} */
2746 @IntrinsicCandidate
2747 public final void putLongRelease(Object o, long offset, long x) {
2748 putLongVolatile(o, offset, x);
2749 }
2750
2751 /** Release version of {@link #putDoubleVolatile(Object, long, double)} */
2752 @IntrinsicCandidate
2753 public final void putDoubleRelease(Object o, long offset, double x) {
2754 putDoubleVolatile(o, offset, x);
2755 }
2756
2757 // ------------------------------ Opaque --------------------------------------
2758
2759 /** Opaque version of {@link #getReferenceVolatile(Object, long)} */
2760 @IntrinsicCandidate
2761 public final Object getReferenceOpaque(Object o, long offset) {
2762 return getReferenceVolatile(o, offset);
2763 }
2764
2765 @ForceInline
2766 public final <V> Object getFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType) {
2767 // this is stronger than opaque semantics
2768 return getFlatValueAcquire(o, offset, layout, valueType);
2769 }
2770
2771 /** Opaque version of {@link #getBooleanVolatile(Object, long)} */
2772 @IntrinsicCandidate
2773 public final boolean getBooleanOpaque(Object o, long offset) {
2774 return getBooleanVolatile(o, offset);
2775 }
2776
2777 /** Opaque version of {@link #getByteVolatile(Object, long)} */
2778 @IntrinsicCandidate
2779 public final byte getByteOpaque(Object o, long offset) {
2780 return getByteVolatile(o, offset);
2781 }
2782
2783 /** Opaque version of {@link #getShortVolatile(Object, long)} */
2784 @IntrinsicCandidate
2785 public final short getShortOpaque(Object o, long offset) {
2786 return getShortVolatile(o, offset);
2787 }
2788
2789 /** Opaque version of {@link #getCharVolatile(Object, long)} */
2790 @IntrinsicCandidate
2805 }
2806
2807 /** Opaque version of {@link #getLongVolatile(Object, long)} */
2808 @IntrinsicCandidate
2809 public final long getLongOpaque(Object o, long offset) {
2810 return getLongVolatile(o, offset);
2811 }
2812
2813 /** Opaque version of {@link #getDoubleVolatile(Object, long)} */
2814 @IntrinsicCandidate
2815 public final double getDoubleOpaque(Object o, long offset) {
2816 return getDoubleVolatile(o, offset);
2817 }
2818
2819 /** Opaque version of {@link #putReferenceVolatile(Object, long, Object)} */
2820 @IntrinsicCandidate
2821 public final void putReferenceOpaque(Object o, long offset, Object x) {
2822 putReferenceVolatile(o, offset, x);
2823 }
2824
2825 @ForceInline
2826 public final <V> void putFlatValueOpaque(Object o, long offset, int layout, Class<?> valueType, V x) {
2827 // this is stronger than opaque semantics
2828 putFlatValueRelease(o, offset, layout, valueType, x);
2829 }
2830
2831 /** Opaque version of {@link #putBooleanVolatile(Object, long, boolean)} */
2832 @IntrinsicCandidate
2833 public final void putBooleanOpaque(Object o, long offset, boolean x) {
2834 putBooleanVolatile(o, offset, x);
2835 }
2836
2837 /** Opaque version of {@link #putByteVolatile(Object, long, byte)} */
2838 @IntrinsicCandidate
2839 public final void putByteOpaque(Object o, long offset, byte x) {
2840 putByteVolatile(o, offset, x);
2841 }
2842
2843 /** Opaque version of {@link #putShortVolatile(Object, long, short)} */
2844 @IntrinsicCandidate
2845 public final void putShortOpaque(Object o, long offset, short x) {
2846 putShortVolatile(o, offset, x);
2847 }
2848
2849 /** Opaque version of {@link #putCharVolatile(Object, long, char)} */
2850 @IntrinsicCandidate
2859 }
2860
2861 /** Opaque version of {@link #putFloatVolatile(Object, long, float)} */
2862 @IntrinsicCandidate
2863 public final void putFloatOpaque(Object o, long offset, float x) {
2864 putFloatVolatile(o, offset, x);
2865 }
2866
2867 /** Opaque version of {@link #putLongVolatile(Object, long, long)} */
2868 @IntrinsicCandidate
2869 public final void putLongOpaque(Object o, long offset, long x) {
2870 putLongVolatile(o, offset, x);
2871 }
2872
2873 /** Opaque version of {@link #putDoubleVolatile(Object, long, double)} */
2874 @IntrinsicCandidate
2875 public final void putDoubleOpaque(Object o, long offset, double x) {
2876 putDoubleVolatile(o, offset, x);
2877 }
2878
2879 @ForceInline
2880 private boolean compareAndSetFlatValueAsBytes(Object o, long offset, int layout, Class<?> valueType, Object expected, Object x) {
2881 // We turn the payload of an atomic value into a numeric value (of suitable type)
2882 // by storing the value into an array element (of matching layout) and by reading
2883 // back the array element as an integral value. After which we can implement the CAS
2884 // as a plain numeric CAS. Note: this only works if the payload contains no oops
2885 // (see VarHandles::isAtomicFlat).
2886 Object[] expectedArray = newSpecialArray(valueType, 1, layout);
2887 Object xArray = newSpecialArray(valueType, 1, layout);
2888 long base = arrayInstanceBaseOffset(expectedArray);
2889 int scale = arrayInstanceIndexScale(expectedArray);
2890 putFlatValue(expectedArray, base, layout, valueType, expected);
2891 putFlatValue(xArray, base, layout, valueType, x);
2892 switch (scale) {
2893 case 1: {
2894 byte expectedByte = getByte(expectedArray, base);
2895 byte xByte = getByte(xArray, base);
2896 return compareAndSetByte(o, offset, expectedByte, xByte);
2897 }
2898 case 2: {
2899 short expectedShort = getShort(expectedArray, base);
2900 short xShort = getShort(xArray, base);
2901 return compareAndSetShort(o, offset, expectedShort, xShort);
2902 }
2903 case 4: {
2904 int expectedInt = getInt(expectedArray, base);
2905 int xInt = getInt(xArray, base);
2906 return compareAndSetInt(o, offset, expectedInt, xInt);
2907 }
2908 case 8: {
2909 long expectedLong = getLong(expectedArray, base);
2910 long xLong = getLong(xArray, base);
2911 return compareAndSetLong(o, offset, expectedLong, xLong);
2912 }
2913 default: {
2914 throw new UnsupportedOperationException();
2915 }
2916 }
2917 }
2918
2919 /**
2920 * Unblocks the given thread blocked on {@code park}, or, if it is
2921 * not blocked, causes the subsequent call to {@code park} not to
2922 * block. Note: this operation is "unsafe" solely because the
2923 * caller must somehow ensure that the thread has not been
2924 * destroyed. Nothing special is usually required to ensure this
2925 * when called from Java (in which there will ordinarily be a live
2926 * reference to the thread) but this is not nearly-automatically
2927 * so when calling from native code.
2928 *
2929 * @param thread the thread to unpark.
2930 */
2931 @IntrinsicCandidate
2932 public native void unpark(Object thread);
2933
2934 /**
2935 * Blocks current thread, returning when a balancing
2936 * {@code unpark} occurs, or a balancing {@code unpark} has
2937 * already occurred, or the thread is interrupted, or, if not
2938 * absolute and time is not zero, the given time nanoseconds have
3285 /**
3286 * Atomically exchanges the given reference value with the current
3287 * reference value of a field or array element within the given
3288 * object {@code o} at the given {@code offset}.
3289 *
3290 * @param o object/array to update the field/element in
3291 * @param offset field/element offset
3292 * @param newValue new value
3293 * @return the previous value
3294 * @since 1.8
3295 */
3296 @IntrinsicCandidate
3297 public final Object getAndSetReference(Object o, long offset, Object newValue) {
3298 Object v;
3299 do {
3300 v = getReferenceVolatile(o, offset);
3301 } while (!weakCompareAndSetReference(o, offset, v, newValue));
3302 return v;
3303 }
3304
3305 @ForceInline
3306 public final Object getAndSetReference(Object o, long offset, Class<?> valueType, Object newValue) {
3307 Object v;
3308 do {
3309 v = getReferenceVolatile(o, offset);
3310 } while (!compareAndSetReference(o, offset, valueType, v, newValue));
3311 return v;
3312 }
3313
3314 @ForceInline
3315 public Object getAndSetFlatValue(Object o, long offset, int layoutKind, Class<?> valueType, Object newValue) {
3316 Object v;
3317 do {
3318 v = getFlatValueVolatile(o, offset, layoutKind, valueType);
3319 } while (!compareAndSetFlatValue(o, offset, layoutKind, valueType, v, newValue));
3320 return v;
3321 }
3322
3323 @ForceInline
3324 public final Object getAndSetReferenceRelease(Object o, long offset, Object newValue) {
3325 Object v;
3326 do {
3327 v = getReference(o, offset);
3328 } while (!weakCompareAndSetReferenceRelease(o, offset, v, newValue));
3329 return v;
3330 }
3331
3332 @ForceInline
3333 public final Object getAndSetReferenceRelease(Object o, long offset, Class<?> valueType, Object newValue) {
3334 return getAndSetReference(o, offset, valueType, newValue);
3335 }
3336
3337 @ForceInline
3338 public Object getAndSetFlatValueRelease(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3339 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3340 }
3341
3342 @ForceInline
3343 public final Object getAndSetReferenceAcquire(Object o, long offset, Object newValue) {
3344 Object v;
3345 do {
3346 v = getReferenceAcquire(o, offset);
3347 } while (!weakCompareAndSetReferenceAcquire(o, offset, v, newValue));
3348 return v;
3349 }
3350
3351 @ForceInline
3352 public final Object getAndSetReferenceAcquire(Object o, long offset, Class<?> valueType, Object newValue) {
3353 return getAndSetReference(o, offset, valueType, newValue);
3354 }
3355
3356 @ForceInline
3357 public Object getAndSetFlatValueAcquire(Object o, long offset, int layoutKind, Class<?> valueType, Object x) {
3358 return getAndSetFlatValue(o, offset, layoutKind, valueType, x);
3359 }
3360
3361 @IntrinsicCandidate
3362 public final byte getAndSetByte(Object o, long offset, byte newValue) {
3363 byte v;
3364 do {
3365 v = getByteVolatile(o, offset);
3366 } while (!weakCompareAndSetByte(o, offset, v, newValue));
3367 return v;
3368 }
3369
3370 @ForceInline
3371 public final byte getAndSetByteRelease(Object o, long offset, byte newValue) {
3372 byte v;
3373 do {
3374 v = getByte(o, offset);
3375 } while (!weakCompareAndSetByteRelease(o, offset, v, newValue));
3376 return v;
3377 }
3378
3379 @ForceInline
3380 public final byte getAndSetByteAcquire(Object o, long offset, byte newValue) {
4396 private static short convEndian(boolean big, short n) { return big == BIG_ENDIAN ? n : Short.reverseBytes(n) ; }
4397 private static int convEndian(boolean big, int n) { return big == BIG_ENDIAN ? n : Integer.reverseBytes(n) ; }
4398 private static long convEndian(boolean big, long n) { return big == BIG_ENDIAN ? n : Long.reverseBytes(n) ; }
4399
4400
4401
4402 private native long allocateMemory0(long bytes);
4403 private native long reallocateMemory0(long address, long bytes);
4404 private native void freeMemory0(long address);
4405 @IntrinsicCandidate
4406 private native void setMemory0(Object o, long offset, long bytes, byte value);
4407 @IntrinsicCandidate
4408 private native void copyMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes);
4409 private native void copySwapMemory0(Object srcBase, long srcOffset, Object destBase, long destOffset, long bytes, long elemSize);
4410 private native long objectFieldOffset0(Field f); // throws IAE
4411 private native long knownObjectFieldOffset0(Class<?> c, String name); // error code: -1 not found, -2 static
4412 private native long staticFieldOffset0(Field f); // throws IAE
4413 private native Object staticFieldBase0(Field f); // throws IAE
4414 private native boolean shouldBeInitialized0(Class<?> c);
4415 private native void ensureClassInitialized0(Class<?> c);
4416 private native void notifyStrictStaticAccess0(Class<?> c, long staticFieldOffset, boolean writing);
4417 private native int arrayBaseOffset0(Class<?> arrayClass); // public version returns long to promote correct arithmetic
4418 @IntrinsicCandidate
4419 private native int arrayInstanceBaseOffset0(Object[] array);
4420 private native int arrayIndexScale0(Class<?> arrayClass);
4421 @IntrinsicCandidate
4422 private native int arrayInstanceIndexScale0(Object[] array);
4423 private native long getObjectSize0(Object o);
4424 private native int getLoadAverage0(double[] loadavg, int nelems);
4425 private native int[] getFieldMap0(Class <?> c);
4426
4427
4428 /**
4429 * Invokes the given direct byte buffer's cleaner, if any.
4430 *
4431 * @param directBuffer a direct byte buffer
4432 * @throws NullPointerException if {@code directBuffer} is null
4433 * @throws IllegalArgumentException if {@code directBuffer} is non-direct,
4434 * or is a {@link java.nio.Buffer#slice slice}, or is a
4435 * {@link java.nio.Buffer#duplicate duplicate}
4436 */
4437 public void invokeCleaner(java.nio.ByteBuffer directBuffer) {
4438 if (!directBuffer.isDirect())
4439 throw new IllegalArgumentException("buffer is non-direct");
4440
4441 DirectBuffer db = (DirectBuffer) directBuffer;
4442 if (db.attachment() != null)
4443 throw new IllegalArgumentException("duplicate or slice");
4444
4445 Cleaner cleaner = db.cleaner();
|