1 /*
2 * Copyright (c) 2000, 2016, 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.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "classfile/classFileStream.hpp"
27 #include "classfile/vmSymbols.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "oops/objArrayOop.inline.hpp"
30 #include "oops/oop.inline.hpp"
31 #include "prims/jni.h"
32 #include "prims/jvm.h"
33 #include "runtime/atomic.inline.hpp"
34 #include "runtime/globals.hpp"
35 #include "runtime/interfaceSupport.hpp"
36 #include "runtime/orderAccess.inline.hpp"
37 #include "runtime/reflection.hpp"
38 #include "runtime/vm_version.hpp"
39 #include "services/threadService.hpp"
40 #include "trace/tracing.hpp"
41 #include "utilities/copy.hpp"
42 #include "utilities/dtrace.hpp"
43 #include "utilities/macros.hpp"
44 #if INCLUDE_ALL_GCS
45 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
46 #endif // INCLUDE_ALL_GCS
47
48 /*
49 * Implementation of class Unsafe
50 */
51
52
53 #define MAX_OBJECT_SIZE \
54 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
55 + ((julong)max_jint * sizeof(double)) )
56
57
58 #define UNSAFE_ENTRY(result_type, header) \
59 JVM_ENTRY(result_type, header)
60
61 // Can't use UNSAFE_LEAF because it has the signature of a straight
62 // call into the runtime (just like JVM_LEAF, funny that) but it's
63 // called like a Java Native and thus the wrapper built for it passes
64 // arguments like a JNI call. It expects those arguments to be popped
65 // from the stack on Intel like all good JNI args are, and adjusts the
66 // stack according. Since the JVM_LEAF call expects no extra
67 // arguments the stack isn't popped in the C code, is pushed by the
68 // wrapper and we get sick.
69 //#define UNSAFE_LEAF(result_type, header) \
70 // JVM_LEAF(result_type, header)
71
72 #define UNSAFE_END JVM_END
73
74 #define UnsafeWrapper(arg) /*nothing, for the present*/
75
76
77 inline void* addr_from_java(jlong addr) {
78 // This assert fails in a variety of ways on 32-bit systems.
79 // It is impossible to predict whether native code that converts
80 // pointers to longs will sign-extend or zero-extend the addresses.
81 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
82 return (void*)(uintptr_t)addr;
83 }
84
85 inline jlong addr_to_java(void* p) {
86 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
87 return (uintptr_t)p;
88 }
89
90
91 // Note: The VM's obj_field and related accessors use byte-scaled
92 // ("unscaled") offsets, just as the unsafe methods do.
93
94 // However, the method Unsafe.fieldOffset explicitly declines to
95 // guarantee this. The field offset values manipulated by the Java user
96 // through the Unsafe API are opaque cookies that just happen to be byte
97 // offsets. We represent this state of affairs by passing the cookies
98 // through conversion functions when going between the VM and the Unsafe API.
99 // The conversion functions just happen to be no-ops at present.
100
101 inline jlong field_offset_to_byte_offset(jlong field_offset) {
102 return field_offset;
103 }
104
105 inline jlong field_offset_from_byte_offset(jlong byte_offset) {
106 return byte_offset;
107 }
108
109 inline jint invocation_key_from_method_slot(jint slot) {
110 return slot;
111 }
112
113 inline jint invocation_key_to_method_slot(jint key) {
114 return key;
115 }
116
117 inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
118 jlong byte_offset = field_offset_to_byte_offset(field_offset);
119 #ifdef ASSERT
120 if (p != NULL) {
121 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
122 if (byte_offset == (jint)byte_offset) {
123 void* ptr_plus_disp = (address)p + byte_offset;
124 assert((void*)p->obj_field_addr<oop>((jint)byte_offset) == ptr_plus_disp,
125 "raw [ptr+disp] must be consistent with oop::field_base");
126 }
127 jlong p_size = HeapWordSize * (jlong)(p->size());
128 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, byte_offset, p_size);
129 }
130 #endif
131 if (sizeof(char*) == sizeof(jint)) // (this constant folds!)
132 return (address)p + (jint) byte_offset;
133 else
134 return (address)p + byte_offset;
135 }
136
137 // Externally callable versions:
138 // (Use these in compiler intrinsics which emulate unsafe primitives.)
139 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
140 return field_offset;
141 }
142 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
143 return byte_offset;
144 }
145 jint Unsafe_invocation_key_from_method_slot(jint slot) {
146 return invocation_key_from_method_slot(slot);
147 }
148 jint Unsafe_invocation_key_to_method_slot(jint key) {
149 return invocation_key_to_method_slot(key);
150 }
151
152
153 ///// Data in the Java heap.
154
155 #define GET_FIELD(obj, offset, type_name, v) \
156 oop p = JNIHandles::resolve(obj); \
157 type_name v = *(type_name*)index_oop_from_field_offset_long(p, offset)
158
159 #define SET_FIELD(obj, offset, type_name, x) \
160 oop p = JNIHandles::resolve(obj); \
161 *(type_name*)index_oop_from_field_offset_long(p, offset) = x
162
163 #define GET_FIELD_VOLATILE(obj, offset, type_name, v) \
164 oop p = JNIHandles::resolve(obj); \
165 if (support_IRIW_for_not_multiple_copy_atomic_cpu) { \
166 OrderAccess::fence(); \
167 } \
168 volatile type_name v = OrderAccess::load_acquire((volatile type_name*)index_oop_from_field_offset_long(p, offset));
169
170 #define SET_FIELD_VOLATILE(obj, offset, type_name, x) \
171 oop p = JNIHandles::resolve(obj); \
172 OrderAccess::release_store_fence((volatile type_name*)index_oop_from_field_offset_long(p, offset), x);
173
174
175 // Get/SetObject must be special-cased, since it works with handles.
176
177 // These functions allow a null base pointer with an arbitrary address.
178 // But if the base pointer is non-null, the offset should make some sense.
179 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
180 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
181 UnsafeWrapper("Unsafe_GetObject");
182 oop p = JNIHandles::resolve(obj);
183 oop v;
184 if (UseCompressedOops) {
185 narrowOop n = *(narrowOop*)index_oop_from_field_offset_long(p, offset);
186 v = oopDesc::decode_heap_oop(n);
187 } else {
188 v = *(oop*)index_oop_from_field_offset_long(p, offset);
189 }
190 jobject ret = JNIHandles::make_local(env, v);
191 #if INCLUDE_ALL_GCS
192 // We could be accessing the referent field in a reference
193 // object. If G1 is enabled then we need to register non-null
194 // referent with the SATB barrier.
195 if (UseG1GC) {
196 bool needs_barrier = false;
197
198 if (ret != NULL) {
199 if (offset == java_lang_ref_Reference::referent_offset && obj != NULL) {
200 oop o = JNIHandles::resolve(obj);
201 Klass* k = o->klass();
202 if (InstanceKlass::cast(k)->reference_type() != REF_NONE) {
203 assert(InstanceKlass::cast(k)->is_subclass_of(SystemDictionary::Reference_klass()), "sanity");
204 needs_barrier = true;
205 }
206 }
207 }
208
209 if (needs_barrier) {
210 oop referent = JNIHandles::resolve(ret);
211 G1SATBCardTableModRefBS::enqueue(referent);
212 }
213 }
214 #endif // INCLUDE_ALL_GCS
215 return ret;
216 UNSAFE_END
217
218 UNSAFE_ENTRY(void, Unsafe_SetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
219 UnsafeWrapper("Unsafe_SetObject");
220 oop x = JNIHandles::resolve(x_h);
221 oop p = JNIHandles::resolve(obj);
222 if (UseCompressedOops) {
223 oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
224 } else {
225 oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
226 }
227 UNSAFE_END
228
229 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
230 UnsafeWrapper("Unsafe_GetObjectVolatile");
231 oop p = JNIHandles::resolve(obj);
232 void* addr = index_oop_from_field_offset_long(p, offset);
233 volatile oop v;
234 if (UseCompressedOops) {
235 volatile narrowOop n = *(volatile narrowOop*) addr;
236 (void)const_cast<oop&>(v = oopDesc::decode_heap_oop(n));
237 } else {
238 (void)const_cast<oop&>(v = *(volatile oop*) addr);
239 }
240 OrderAccess::acquire();
241 return JNIHandles::make_local(env, v);
242 UNSAFE_END
243
244 UNSAFE_ENTRY(void, Unsafe_SetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
245 UnsafeWrapper("Unsafe_SetObjectVolatile");
246 oop x = JNIHandles::resolve(x_h);
247 oop p = JNIHandles::resolve(obj);
248 void* addr = index_oop_from_field_offset_long(p, offset);
249 OrderAccess::release();
250 if (UseCompressedOops) {
251 oop_store((narrowOop*)addr, x);
252 } else {
253 oop_store((oop*)addr, x);
254 }
255 OrderAccess::fence();
256 UNSAFE_END
257
258 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr))
259 UnsafeWrapper("Unsafe_GetUncompressedObject");
260 oop v = *(oop*) (address) addr;
261 return JNIHandles::make_local(env, v);
262 UNSAFE_END
263
264 UNSAFE_ENTRY(jclass, Unsafe_GetJavaMirror(JNIEnv *env, jobject unsafe, jlong metaspace_klass))
265 UnsafeWrapper("Unsafe_GetJavaMirror");
266 Klass* klass = (Klass*) (address) metaspace_klass;
267 return (jclass) JNIHandles::make_local(klass->java_mirror());
268 UNSAFE_END
269
270 UNSAFE_ENTRY(jlong, Unsafe_GetKlassPointer(JNIEnv *env, jobject unsafe, jobject obj))
271 UnsafeWrapper("Unsafe_GetKlassPointer");
272 oop o = JNIHandles::resolve(obj);
273 jlong klass = (jlong) (address) o->klass();
274 return klass;
275 UNSAFE_END
276
277 #ifndef SUPPORTS_NATIVE_CX8
278
279 // VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'.
280 //
281 // On platforms which do not support atomic compare-and-swap of jlong (8 byte)
282 // values we have to use a lock-based scheme to enforce atomicity. This has to be
283 // applied to all Unsafe operations that set the value of a jlong field. Even so
284 // the compareAndSwapLong operation will not be atomic with respect to direct stores
285 // to the field from Java code. It is important therefore that any Java code that
286 // utilizes these Unsafe jlong operations does not perform direct stores. To permit
287 // direct loads of the field from Java code we must also use Atomic::store within the
288 // locked regions. And for good measure, in case there are direct stores, we also
289 // employ Atomic::load within those regions. Note that the field in question must be
290 // volatile and so must have atomic load/store accesses applied at the Java level.
291 //
292 // The locking scheme could utilize a range of strategies for controlling the locking
293 // granularity: from a lock per-field through to a single global lock. The latter is
294 // the simplest and is used for the current implementation. Note that the Java object
295 // that contains the field, can not, in general, be used for locking. To do so can lead
296 // to deadlocks as we may introduce locking into what appears to the Java code to be a
297 // lock-free path.
298 //
299 // As all the locked-regions are very short and themselves non-blocking we can treat
300 // them as leaf routines and elide safepoint checks (ie we don't perform any thread
301 // state transitions even when blocking for the lock). Note that if we do choose to
302 // add safepoint checks and thread state transitions, we must ensure that we calculate
303 // the address of the field _after_ we have acquired the lock, else the object may have
304 // been moved by the GC
305
306 UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
307 UnsafeWrapper("Unsafe_GetLongVolatile");
308 {
309 if (VM_Version::supports_cx8()) {
310 GET_FIELD_VOLATILE(obj, offset, jlong, v);
311 return v;
312 }
313 else {
314 Handle p (THREAD, JNIHandles::resolve(obj));
315 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
316 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
317 jlong value = Atomic::load(addr);
318 return value;
319 }
320 }
321 UNSAFE_END
322
323 UNSAFE_ENTRY(void, Unsafe_SetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
324 UnsafeWrapper("Unsafe_SetLongVolatile");
325 {
326 if (VM_Version::supports_cx8()) {
327 SET_FIELD_VOLATILE(obj, offset, jlong, x);
328 }
329 else {
330 Handle p (THREAD, JNIHandles::resolve(obj));
331 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
332 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
333 Atomic::store(x, addr);
334 }
335 }
336 UNSAFE_END
337
338 #endif // not SUPPORTS_NATIVE_CX8
339
340 UNSAFE_ENTRY(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe))
341 UnsafeWrapper("Unsafe_IsBigEndian0");
342 {
343 #ifdef VM_LITTLE_ENDIAN
344 return false;
345 #else
346 return true;
347 #endif
348 }
349 UNSAFE_END
350
351 UNSAFE_ENTRY(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe))
352 UnsafeWrapper("Unsafe_UnalignedAccess0");
353 {
354 return UseUnalignedAccesses;
355 }
356 UNSAFE_END
357
358 #define DEFINE_GETSETOOP(jboolean, Boolean) \
359 \
360 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset)) \
361 UnsafeWrapper("Unsafe_Get"#Boolean); \
362 if (obj == NULL) THROW_0(vmSymbols::java_lang_NullPointerException()); \
363 GET_FIELD(obj, offset, jboolean, v); \
364 return v; \
365 UNSAFE_END \
366 \
367 UNSAFE_ENTRY(void, Unsafe_Set##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset, jboolean x)) \
368 UnsafeWrapper("Unsafe_Set"#Boolean); \
369 if (obj == NULL) THROW(vmSymbols::java_lang_NullPointerException()); \
370 SET_FIELD(obj, offset, jboolean, x); \
371 UNSAFE_END \
372 \
373 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \
374 UnsafeWrapper("Unsafe_Get"#Boolean); \
375 GET_FIELD(obj, offset, jboolean, v); \
376 return v; \
377 UNSAFE_END \
378 \
379 UNSAFE_ENTRY(void, Unsafe_Set##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \
380 UnsafeWrapper("Unsafe_Set"#Boolean); \
381 SET_FIELD(obj, offset, jboolean, x); \
382 UNSAFE_END \
383 \
384 // END DEFINE_GETSETOOP.
385
386 DEFINE_GETSETOOP(jboolean, Boolean)
387 DEFINE_GETSETOOP(jbyte, Byte)
388 DEFINE_GETSETOOP(jshort, Short);
389 DEFINE_GETSETOOP(jchar, Char);
390 DEFINE_GETSETOOP(jint, Int);
391 DEFINE_GETSETOOP(jlong, Long);
392 DEFINE_GETSETOOP(jfloat, Float);
393 DEFINE_GETSETOOP(jdouble, Double);
394
395 #undef DEFINE_GETSETOOP
396
397 #define DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) \
398 \
399 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \
400 UnsafeWrapper("Unsafe_Get"#Boolean); \
401 GET_FIELD_VOLATILE(obj, offset, jboolean, v); \
402 return v; \
403 UNSAFE_END \
404 \
405 UNSAFE_ENTRY(void, Unsafe_Set##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \
406 UnsafeWrapper("Unsafe_Set"#Boolean); \
407 SET_FIELD_VOLATILE(obj, offset, jboolean, x); \
408 UNSAFE_END \
409 \
410 // END DEFINE_GETSETOOP_VOLATILE.
411
412 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
413 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
414 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
415 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
416 DEFINE_GETSETOOP_VOLATILE(jint, Int);
417 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
418 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
419
420 #ifdef SUPPORTS_NATIVE_CX8
421 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
422 #endif
423
424 #undef DEFINE_GETSETOOP_VOLATILE
425
426 // The non-intrinsified versions of setOrdered just use setVolatile
427
428 UNSAFE_ENTRY(void, Unsafe_SetOrderedInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint x))
429 UnsafeWrapper("Unsafe_SetOrderedInt");
430 SET_FIELD_VOLATILE(obj, offset, jint, x);
431 UNSAFE_END
432
433 UNSAFE_ENTRY(void, Unsafe_SetOrderedObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
434 UnsafeWrapper("Unsafe_SetOrderedObject");
435 oop x = JNIHandles::resolve(x_h);
436 oop p = JNIHandles::resolve(obj);
437 void* addr = index_oop_from_field_offset_long(p, offset);
438 OrderAccess::release();
439 if (UseCompressedOops) {
440 oop_store((narrowOop*)addr, x);
441 } else {
442 oop_store((oop*)addr, x);
443 }
444 OrderAccess::fence();
445 UNSAFE_END
446
447 UNSAFE_ENTRY(void, Unsafe_SetOrderedLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
448 UnsafeWrapper("Unsafe_SetOrderedLong");
449 #ifdef SUPPORTS_NATIVE_CX8
450 SET_FIELD_VOLATILE(obj, offset, jlong, x);
451 #else
452 // Keep old code for platforms which may not have atomic long (8 bytes) instructions
453 {
454 if (VM_Version::supports_cx8()) {
455 SET_FIELD_VOLATILE(obj, offset, jlong, x);
456 }
457 else {
458 Handle p (THREAD, JNIHandles::resolve(obj));
459 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
460 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
461 Atomic::store(x, addr);
462 }
463 }
464 #endif
465 UNSAFE_END
466
467 UNSAFE_ENTRY(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe))
468 UnsafeWrapper("Unsafe_LoadFence");
469 OrderAccess::acquire();
470 UNSAFE_END
471
472 UNSAFE_ENTRY(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe))
473 UnsafeWrapper("Unsafe_StoreFence");
474 OrderAccess::release();
475 UNSAFE_END
476
477 UNSAFE_ENTRY(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe))
478 UnsafeWrapper("Unsafe_FullFence");
479 OrderAccess::fence();
480 UNSAFE_END
481
482 ////// Data in the C heap.
483
484 // Note: These do not throw NullPointerException for bad pointers.
485 // They just crash. Only a oop base pointer can generate a NullPointerException.
486 //
487 #define DEFINE_GETSETNATIVE(java_type, Type, native_type) \
488 \
489 UNSAFE_ENTRY(java_type, Unsafe_GetNative##Type(JNIEnv *env, jobject unsafe, jlong addr)) \
490 UnsafeWrapper("Unsafe_GetNative"#Type); \
491 void* p = addr_from_java(addr); \
492 JavaThread* t = JavaThread::current(); \
493 t->set_doing_unsafe_access(true); \
494 java_type x = *(volatile native_type*)p; \
495 t->set_doing_unsafe_access(false); \
496 return x; \
497 UNSAFE_END \
498 \
499 UNSAFE_ENTRY(void, Unsafe_SetNative##Type(JNIEnv *env, jobject unsafe, jlong addr, java_type x)) \
500 UnsafeWrapper("Unsafe_SetNative"#Type); \
501 JavaThread* t = JavaThread::current(); \
502 t->set_doing_unsafe_access(true); \
503 void* p = addr_from_java(addr); \
504 *(volatile native_type*)p = x; \
505 t->set_doing_unsafe_access(false); \
506 UNSAFE_END \
507 \
508 // END DEFINE_GETSETNATIVE.
509
510 DEFINE_GETSETNATIVE(jbyte, Byte, signed char)
511 DEFINE_GETSETNATIVE(jshort, Short, signed short);
512 DEFINE_GETSETNATIVE(jchar, Char, unsigned short);
513 DEFINE_GETSETNATIVE(jint, Int, jint);
514 // no long -- handled specially
515 DEFINE_GETSETNATIVE(jfloat, Float, float);
516 DEFINE_GETSETNATIVE(jdouble, Double, double);
517
518 #undef DEFINE_GETSETNATIVE
519
520 UNSAFE_ENTRY(jlong, Unsafe_GetNativeLong(JNIEnv *env, jobject unsafe, jlong addr))
521 UnsafeWrapper("Unsafe_GetNativeLong");
522 JavaThread* t = JavaThread::current();
523 // We do it this way to avoid problems with access to heap using 64
524 // bit loads, as jlong in heap could be not 64-bit aligned, and on
525 // some CPUs (SPARC) it leads to SIGBUS.
526 t->set_doing_unsafe_access(true);
527 void* p = addr_from_java(addr);
528 jlong x;
529 if (((intptr_t)p & 7) == 0) {
530 // jlong is aligned, do a volatile access
531 x = *(volatile jlong*)p;
532 } else {
533 jlong_accessor acc;
534 acc.words[0] = ((volatile jint*)p)[0];
535 acc.words[1] = ((volatile jint*)p)[1];
536 x = acc.long_value;
537 }
538 t->set_doing_unsafe_access(false);
539 return x;
540 UNSAFE_END
541
542 UNSAFE_ENTRY(void, Unsafe_SetNativeLong(JNIEnv *env, jobject unsafe, jlong addr, jlong x))
543 UnsafeWrapper("Unsafe_SetNativeLong");
544 JavaThread* t = JavaThread::current();
545 // see comment for Unsafe_GetNativeLong
546 t->set_doing_unsafe_access(true);
547 void* p = addr_from_java(addr);
548 if (((intptr_t)p & 7) == 0) {
549 // jlong is aligned, do a volatile access
550 *(volatile jlong*)p = x;
551 } else {
552 jlong_accessor acc;
553 acc.long_value = x;
554 ((volatile jint*)p)[0] = acc.words[0];
555 ((volatile jint*)p)[1] = acc.words[1];
556 }
557 t->set_doing_unsafe_access(false);
558 UNSAFE_END
559
560
561 UNSAFE_ENTRY(jlong, Unsafe_GetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr))
562 UnsafeWrapper("Unsafe_GetNativeAddress");
563 void* p = addr_from_java(addr);
564 return addr_to_java(*(void**)p);
565 UNSAFE_END
566
567 UNSAFE_ENTRY(void, Unsafe_SetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr, jlong x))
568 UnsafeWrapper("Unsafe_SetNativeAddress");
569 void* p = addr_from_java(addr);
570 *(void**)p = addr_from_java(x);
571 UNSAFE_END
572
573
574 ////// Allocation requests
575
576 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls))
577 UnsafeWrapper("Unsafe_AllocateInstance");
578 {
579 ThreadToNativeFromVM ttnfv(thread);
580 return env->AllocObject(cls);
581 }
582 UNSAFE_END
583
584 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory(JNIEnv *env, jobject unsafe, jlong size))
585 UnsafeWrapper("Unsafe_AllocateMemory");
586 size_t sz = (size_t)size;
587 if (sz != (julong)size || size < 0) {
588 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
589 }
590 if (sz == 0) {
591 return 0;
592 }
593 sz = round_to(sz, HeapWordSize);
594 void* x = os::malloc(sz, mtInternal);
595 if (x == NULL) {
596 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
597 }
598 //Copy::fill_to_words((HeapWord*)x, sz / HeapWordSize);
599 return addr_to_java(x);
600 UNSAFE_END
601
602 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory(JNIEnv *env, jobject unsafe, jlong addr, jlong size))
603 UnsafeWrapper("Unsafe_ReallocateMemory");
604 void* p = addr_from_java(addr);
605 size_t sz = (size_t)size;
606 if (sz != (julong)size || size < 0) {
607 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
608 }
609 if (sz == 0) {
610 os::free(p);
611 return 0;
612 }
613 sz = round_to(sz, HeapWordSize);
614 void* x = (p == NULL) ? os::malloc(sz, mtInternal) : os::realloc(p, sz, mtInternal);
615 if (x == NULL) {
616 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
617 }
618 return addr_to_java(x);
619 UNSAFE_END
620
621 UNSAFE_ENTRY(void, Unsafe_FreeMemory(JNIEnv *env, jobject unsafe, jlong addr))
622 UnsafeWrapper("Unsafe_FreeMemory");
623 void* p = addr_from_java(addr);
624 if (p == NULL) {
625 return;
626 }
627 os::free(p);
628 UNSAFE_END
629
630 UNSAFE_ENTRY(void, Unsafe_SetMemory(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value))
631 UnsafeWrapper("Unsafe_SetMemory");
632 size_t sz = (size_t)size;
633 if (sz != (julong)size || size < 0) {
634 THROW(vmSymbols::java_lang_IllegalArgumentException());
635 }
636 oop base = JNIHandles::resolve(obj);
637 void* p = index_oop_from_field_offset_long(base, offset);
638 Copy::fill_to_memory_atomic(p, sz, value);
639 UNSAFE_END
640
641 UNSAFE_ENTRY(void, Unsafe_CopyMemory(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size))
642 UnsafeWrapper("Unsafe_CopyMemory");
643 if (size == 0) {
644 return;
645 }
646 size_t sz = (size_t)size;
647 if (sz != (julong)size || size < 0) {
648 THROW(vmSymbols::java_lang_IllegalArgumentException());
649 }
650 oop srcp = JNIHandles::resolve(srcObj);
651 oop dstp = JNIHandles::resolve(dstObj);
652 if (dstp != NULL && !dstp->is_typeArray()) {
653 // NYI: This works only for non-oop arrays at present.
654 // Generalizing it would be reasonable, but requires card marking.
655 // Also, autoboxing a Long from 0L in copyMemory(x,y, 0L,z, n) would be bad.
656 THROW(vmSymbols::java_lang_IllegalArgumentException());
657 }
658 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
659 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
660 Copy::conjoint_memory_atomic(src, dst, sz);
661 UNSAFE_END
662
663 // This function is a leaf since if the source and destination are both in native memory
664 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
665 // If either source or destination (or both) are on the heap, the function will enter VM using
666 // JVM_ENTRY_FROM_LEAF
667 JVM_LEAF(void, Unsafe_CopySwapMemory(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize))
668 UnsafeWrapper("Unsafe_CopySwapMemory");
669 if (size == 0) {
670 return;
671 }
672
673 size_t sz = (size_t)size;
674 if (sz != (julong)size || size < 0) {
675 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory) {
676 THROW(vmSymbols::java_lang_IllegalArgumentException());
677 } JVM_END
678 }
679
680 size_t esz = (size_t)elemSize;
681 if (esz != 2 && esz != 4 && esz != 8) {
682 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory) {
683 THROW(vmSymbols::java_lang_IllegalArgumentException());
684 } JVM_END
685 }
686
687 if (!is_size_aligned(sz, esz)) {
688 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory) {
689 THROW(vmSymbols::java_lang_IllegalArgumentException());
690 } JVM_END
691 }
692
693 if (srcObj == NULL && dstObj == NULL) {
694 // Both src & dst are in native memory
695 address src = (address)srcOffset;
696 address dst = (address)dstOffset;
697
698 if (src == NULL || dst == NULL) {
699 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory) {
700 THROW(vmSymbols::java_lang_NullPointerException());
701 } JVM_END
702 }
703
704 Copy::conjoint_swap(src, dst, sz, esz);
705 } else {
706 // At least one of src/dst are on heap, transition to VM to access raw pointers
707
708 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory) {
709 oop srcp = JNIHandles::resolve(srcObj);
710 oop dstp = JNIHandles::resolve(dstObj);
711
712 if (dstp != NULL && !dstp->is_typeArray()) {
713 // NYI: This works only for non-oop arrays at present.
714 // Generalizing it would be reasonable, but requires card marking.
715 // Also, autoboxing a Long from 0L in copyMemory(x,y, 0L,z, n) would be bad.
716 THROW(vmSymbols::java_lang_IllegalArgumentException());
717 }
718
719 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
720 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
721
722 Copy::conjoint_swap(src, dst, sz, esz);
723 } JVM_END
724 }
725 JVM_END
726
727
728 ////// Random queries
729
730 // See comment at file start about UNSAFE_LEAF
731 //UNSAFE_LEAF(jint, Unsafe_AddressSize())
732 UNSAFE_ENTRY(jint, Unsafe_AddressSize(JNIEnv *env, jobject unsafe))
733 UnsafeWrapper("Unsafe_AddressSize");
734 return sizeof(void*);
735 UNSAFE_END
736
737 // See comment at file start about UNSAFE_LEAF
738 //UNSAFE_LEAF(jint, Unsafe_PageSize())
739 UNSAFE_ENTRY(jint, Unsafe_PageSize(JNIEnv *env, jobject unsafe))
740 UnsafeWrapper("Unsafe_PageSize");
741 return os::vm_page_size();
742 UNSAFE_END
743
744 jint find_field_offset(jobject field, int must_be_static, TRAPS) {
745 if (field == NULL) {
746 THROW_0(vmSymbols::java_lang_NullPointerException());
747 }
748
749 oop reflected = JNIHandles::resolve_non_null(field);
750 oop mirror = java_lang_reflect_Field::clazz(reflected);
751 Klass* k = java_lang_Class::as_Klass(mirror);
752 int slot = java_lang_reflect_Field::slot(reflected);
753 int modifiers = java_lang_reflect_Field::modifiers(reflected);
754
755 if (must_be_static >= 0) {
756 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
757 if (must_be_static != really_is_static) {
758 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
759 }
760 }
761
762 int offset = InstanceKlass::cast(k)->field_offset(slot);
763 return field_offset_from_byte_offset(offset);
764 }
765
766 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset(JNIEnv *env, jobject unsafe, jobject field))
767 UnsafeWrapper("Unsafe_ObjectFieldOffset");
768 return find_field_offset(field, 0, THREAD);
769 UNSAFE_END
770
771 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset(JNIEnv *env, jobject unsafe, jobject field))
772 UnsafeWrapper("Unsafe_StaticFieldOffset");
773 return find_field_offset(field, 1, THREAD);
774 UNSAFE_END
775
776 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBaseFromField(JNIEnv *env, jobject unsafe, jobject field))
777 UnsafeWrapper("Unsafe_StaticFieldBase");
778 // Note: In this VM implementation, a field address is always a short
779 // offset from the base of a a klass metaobject. Thus, the full dynamic
780 // range of the return type is never used. However, some implementations
781 // might put the static field inside an array shared by many classes,
782 // or even at a fixed address, in which case the address could be quite
783 // large. In that last case, this function would return NULL, since
784 // the address would operate alone, without any base pointer.
785
786 if (field == NULL) THROW_0(vmSymbols::java_lang_NullPointerException());
787
788 oop reflected = JNIHandles::resolve_non_null(field);
789 oop mirror = java_lang_reflect_Field::clazz(reflected);
790 int modifiers = java_lang_reflect_Field::modifiers(reflected);
791
792 if ((modifiers & JVM_ACC_STATIC) == 0) {
793 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
794 }
795
796 return JNIHandles::make_local(env, mirror);
797 UNSAFE_END
798
799 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) {
800 UnsafeWrapper("Unsafe_EnsureClassInitialized");
801 if (clazz == NULL) {
802 THROW(vmSymbols::java_lang_NullPointerException());
803 }
804 oop mirror = JNIHandles::resolve_non_null(clazz);
805
806 Klass* klass = java_lang_Class::as_Klass(mirror);
807 if (klass != NULL && klass->should_be_initialized()) {
808 InstanceKlass* k = InstanceKlass::cast(klass);
809 k->initialize(CHECK);
810 }
811 }
812 UNSAFE_END
813
814 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) {
815 UnsafeWrapper("Unsafe_ShouldBeInitialized");
816 if (clazz == NULL) {
817 THROW_(vmSymbols::java_lang_NullPointerException(), false);
818 }
819 oop mirror = JNIHandles::resolve_non_null(clazz);
820 Klass* klass = java_lang_Class::as_Klass(mirror);
821 if (klass != NULL && klass->should_be_initialized()) {
822 return true;
823 }
824 return false;
825 }
826 UNSAFE_END
827
828 static void getBaseAndScale(int& base, int& scale, jclass acls, TRAPS) {
829 if (acls == NULL) {
830 THROW(vmSymbols::java_lang_NullPointerException());
831 }
832 oop mirror = JNIHandles::resolve_non_null(acls);
833 Klass* k = java_lang_Class::as_Klass(mirror);
834 if (k == NULL || !k->is_array_klass()) {
835 THROW(vmSymbols::java_lang_InvalidClassException());
836 } else if (k->is_objArray_klass()) {
837 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
838 scale = heapOopSize;
839 } else if (k->is_typeArray_klass()) {
840 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
841 base = tak->array_header_in_bytes();
842 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
843 scale = (1 << tak->log2_element_size());
844 } else {
845 ShouldNotReachHere();
846 }
847 }
848
849 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset(JNIEnv *env, jobject unsafe, jclass acls))
850 UnsafeWrapper("Unsafe_ArrayBaseOffset");
851 int base = 0, scale = 0;
852 getBaseAndScale(base, scale, acls, CHECK_0);
853 return field_offset_from_byte_offset(base);
854 UNSAFE_END
855
856
857 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale(JNIEnv *env, jobject unsafe, jclass acls))
858 UnsafeWrapper("Unsafe_ArrayIndexScale");
859 int base = 0, scale = 0;
860 getBaseAndScale(base, scale, acls, CHECK_0);
861 // This VM packs both fields and array elements down to the byte.
862 // But watch out: If this changes, so that array references for
863 // a given primitive type (say, T_BOOLEAN) use different memory units
864 // than fields, this method MUST return zero for such arrays.
865 // For example, the VM used to store sub-word sized fields in full
866 // words in the object layout, so that accessors like getByte(Object,int)
867 // did not really do what one might expect for arrays. Therefore,
868 // this function used to report a zero scale factor, so that the user
869 // would know not to attempt to access sub-word array elements.
870 // // Code for unpacked fields:
871 // if (scale < wordSize) return 0;
872
873 // The following allows for a pretty general fieldOffset cookie scheme,
874 // but requires it to be linear in byte offset.
875 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
876 UNSAFE_END
877
878
879 static inline void throw_new(JNIEnv *env, const char *ename) {
880 char buf[100];
881 jio_snprintf(buf, 100, "%s%s", "java/lang/", ename);
882 jclass cls = env->FindClass(buf);
883 if (env->ExceptionCheck()) {
884 env->ExceptionClear();
885 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf);
886 return;
887 }
888 char* msg = NULL;
889 env->ThrowNew(cls, msg);
890 }
891
892 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
893 {
894 // Code lifted from JDK 1.3 ClassLoader.c
895
896 jbyte *body;
897 char *utfName;
898 jclass result = 0;
899 char buf[128];
900
901 if (UsePerfData) {
902 ClassLoader::unsafe_defineClassCallCounter()->inc();
903 }
904
905 if (data == NULL) {
906 throw_new(env, "NullPointerException");
907 return 0;
908 }
909
910 /* Work around 4153825. malloc crashes on Solaris when passed a
911 * negative size.
912 */
913 if (length < 0) {
914 throw_new(env, "ArrayIndexOutOfBoundsException");
915 return 0;
916 }
917
918 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
919
920 if (body == 0) {
921 throw_new(env, "OutOfMemoryError");
922 return 0;
923 }
924
925 env->GetByteArrayRegion(data, offset, length, body);
926
927 if (env->ExceptionOccurred())
928 goto free_body;
929
930 if (name != NULL) {
931 uint len = env->GetStringUTFLength(name);
932 int unicode_len = env->GetStringLength(name);
933 if (len >= sizeof(buf)) {
934 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
935 if (utfName == NULL) {
936 throw_new(env, "OutOfMemoryError");
937 goto free_body;
938 }
939 } else {
940 utfName = buf;
941 }
942 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
943 //VerifyFixClassname(utfName);
944 for (uint i = 0; i < len; i++) {
945 if (utfName[i] == '.') utfName[i] = '/';
946 }
947 } else {
948 utfName = NULL;
949 }
950
951 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
952
953 if (utfName && utfName != buf)
954 FREE_C_HEAP_ARRAY(char, utfName);
955
956 free_body:
957 FREE_C_HEAP_ARRAY(jbyte, body);
958 return result;
959 }
960 }
961
962
963 UNSAFE_ENTRY(jclass, Unsafe_DefineClass(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd))
964 UnsafeWrapper("Unsafe_DefineClass");
965 {
966 ThreadToNativeFromVM ttnfv(thread);
967 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
968 }
969 UNSAFE_END
970
971
972 // define a class but do not make it known to the class loader or system dictionary
973 // - host_class: supplies context for linkage, access control, protection domain, and class loader
974 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
975 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
976
977 // When you load an anonymous class U, it works as if you changed its name just before loading,
978 // to a name that you will never use again. Since the name is lost, no other class can directly
979 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
980 // through java.lang.Class methods like Class.newInstance.
981
982 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
983 // The package of an anonymous class is given by the package qualifier on the name under which it was loaded.
984 // An anonymous class also has special privileges to access any member of its host class.
985 // This is the main reason why this loading operation is unsafe. The purpose of this is to
986 // allow language implementations to simulate "open classes"; a host class in effect gets
987 // new code when an anonymous class is loaded alongside it. A less convenient but more
988 // standard way to do this is with reflection, which can also be set to ignore access
989 // restrictions.
990
991 // Access into an anonymous class is possible only through reflection. Therefore, there
992 // are no special access rules for calling into an anonymous class. The relaxed access
993 // rule for the host class is applied in the opposite direction: A host class reflectively
994 // access one of its anonymous classes.
995
996 // If you load the same bytecodes twice, you get two different classes. You can reload
997 // the same bytecodes with or without varying CP patches.
998
999 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
1000 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
1001 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
1002
1003 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
1004 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
1005 // It is not possible for a named class, or an older anonymous class, to refer by
1006 // name (via its CP) to a newer anonymous class.
1007
1008 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
1009 // or type descriptors used in the loaded anonymous class.
1010
1011 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
1012 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
1013 // be changed to println(greeting), where greeting is an arbitrary object created before
1014 // the anonymous class is loaded. This is useful in dynamic languages, in which
1015 // various kinds of metaobjects must be introduced as constants into bytecode.
1016 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
1017 // not just a literal string. For such ldc instructions, the verifier uses the
1018 // type Object instead of String, if the loaded constant is not in fact a String.
1019
1020 static instanceKlassHandle
1021 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
1022 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
1023 HeapWord* *temp_alloc,
1024 TRAPS) {
1025
1026 if (UsePerfData) {
1027 ClassLoader::unsafe_defineClassCallCounter()->inc();
1028 }
1029
1030 if (data == NULL) {
1031 THROW_0(vmSymbols::java_lang_NullPointerException());
1032 }
1033
1034 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
1035 jint word_length = (length + sizeof(HeapWord)-1) / sizeof(HeapWord);
1036 HeapWord* body = NEW_C_HEAP_ARRAY(HeapWord, word_length, mtInternal);
1037 if (body == NULL) {
1038 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
1039 }
1040
1041 // caller responsible to free it:
1042 (*temp_alloc) = body;
1043
1044 {
1045 jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0);
1046 Copy::conjoint_words((HeapWord*) array_base, body, word_length);
1047 }
1048
1049 u1* class_bytes = (u1*) body;
1050 int class_bytes_length = (int) length;
1051 if (class_bytes_length < 0) class_bytes_length = 0;
1052 if (class_bytes == NULL
1053 || host_class == NULL
1054 || length != class_bytes_length)
1055 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
1056
1057 objArrayHandle cp_patches_h;
1058 if (cp_patches_jh != NULL) {
1059 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
1060 if (!p->is_objArray())
1061 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
1062 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
1063 }
1064
1065 const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
1066 assert(host_klass != NULL, "invariant");
1067
1068 const char* host_source = host_klass->external_name();
1069 Handle host_loader(THREAD, host_klass->class_loader());
1070 Handle host_domain(THREAD, host_klass->protection_domain());
1071
1072 GrowableArray<Handle>* cp_patches = NULL;
1073 if (cp_patches_h.not_null()) {
1074 int alen = cp_patches_h->length();
1075 for (int i = alen-1; i >= 0; i--) {
1076 oop p = cp_patches_h->obj_at(i);
1077 if (p != NULL) {
1078 Handle patch(THREAD, p);
1079 if (cp_patches == NULL)
1080 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
1081 cp_patches->at_put(i, patch);
1082 }
1083 }
1084 }
1085
1086 ClassFileStream st(class_bytes,
1087 class_bytes_length,
1088 host_source,
1089 ClassFileStream::verify);
1090
1091 instanceKlassHandle anon_klass;
1092 {
1093 Symbol* no_class_name = NULL;
1094 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
1095 host_loader,
1096 host_domain,
1097 &st,
1098 host_klass,
1099 cp_patches,
1100 CHECK_NULL);
1101 if (anonk == NULL) return NULL;
1102 anon_klass = instanceKlassHandle(THREAD, anonk);
1103 }
1104
1105 return anon_klass;
1106 }
1107
1108 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh))
1109 {
1110 instanceKlassHandle anon_klass;
1111 jobject res_jh = NULL;
1112
1113 UnsafeWrapper("Unsafe_DefineAnonymousClass");
1114 ResourceMark rm(THREAD);
1115
1116 HeapWord* temp_alloc = NULL;
1117
1118 anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data,
1119 cp_patches_jh,
1120 &temp_alloc, THREAD);
1121 if (anon_klass() != NULL)
1122 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
1123
1124 // try/finally clause:
1125 if (temp_alloc != NULL) {
1126 FREE_C_HEAP_ARRAY(HeapWord, temp_alloc);
1127 }
1128
1129 // The anonymous class loader data has been artificially been kept alive to
1130 // this point. The mirror and any instances of this class have to keep
1131 // it alive afterwards.
1132 if (anon_klass() != NULL) {
1133 anon_klass->class_loader_data()->set_keep_alive(false);
1134 }
1135
1136 // let caller initialize it as needed...
1137
1138 return (jclass) res_jh;
1139 }
1140 UNSAFE_END
1141
1142
1143
1144 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr))
1145 UnsafeWrapper("Unsafe_ThrowException");
1146 {
1147 ThreadToNativeFromVM ttnfv(thread);
1148 env->Throw(thr);
1149 }
1150 UNSAFE_END
1151
1152 // JSR166 ------------------------------------------------------------------
1153
1154 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h))
1155 UnsafeWrapper("Unsafe_CompareAndSwapObject");
1156 oop x = JNIHandles::resolve(x_h);
1157 oop e = JNIHandles::resolve(e_h);
1158 oop p = JNIHandles::resolve(obj);
1159 HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
1160 oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
1161 jboolean success = (res == e);
1162 if (success)
1163 update_barrier_set((void*)addr, x);
1164 return success;
1165 UNSAFE_END
1166
1167 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x))
1168 UnsafeWrapper("Unsafe_CompareAndSwapInt");
1169 oop p = JNIHandles::resolve(obj);
1170 jint* addr = (jint *) index_oop_from_field_offset_long(p, offset);
1171 return (jint)(Atomic::cmpxchg(x, addr, e)) == e;
1172 UNSAFE_END
1173
1174 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x))
1175 UnsafeWrapper("Unsafe_CompareAndSwapLong");
1176 Handle p (THREAD, JNIHandles::resolve(obj));
1177 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
1178 #ifdef SUPPORTS_NATIVE_CX8
1179 return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1180 #else
1181 if (VM_Version::supports_cx8())
1182 return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1183 else {
1184 jboolean success = false;
1185 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1186 jlong val = Atomic::load(addr);
1187 if (val == e) { Atomic::store(x, addr); success = true; }
1188 return success;
1189 }
1190 #endif
1191 UNSAFE_END
1192
1193 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time))
1194 UnsafeWrapper("Unsafe_Park");
1195 EventThreadPark event;
1196 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1197
1198 JavaThreadParkedState jtps(thread, time != 0);
1199 thread->parker()->park(isAbsolute != 0, time);
1200
1201 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1202 if (event.should_commit()) {
1203 oop obj = thread->current_park_blocker();
1204 event.set_klass((obj != NULL) ? obj->klass() : NULL);
1205 event.set_timeout(time);
1206 event.set_address((obj != NULL) ? (TYPE_ADDRESS) cast_from_oop<uintptr_t>(obj) : 0);
1207 event.commit();
1208 }
1209 UNSAFE_END
1210
1211 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread))
1212 UnsafeWrapper("Unsafe_Unpark");
1213 Parker* p = NULL;
1214 if (jthread != NULL) {
1215 oop java_thread = JNIHandles::resolve_non_null(jthread);
1216 if (java_thread != NULL) {
1217 jlong lp = java_lang_Thread::park_event(java_thread);
1218 if (lp != 0) {
1219 // This cast is OK even though the jlong might have been read
1220 // non-atomically on 32bit systems, since there, one word will
1221 // always be zero anyway and the value set is always the same
1222 p = (Parker*)addr_from_java(lp);
1223 } else {
1224 // Grab lock if apparently null or using older version of library
1225 MutexLocker mu(Threads_lock);
1226 java_thread = JNIHandles::resolve_non_null(jthread);
1227 if (java_thread != NULL) {
1228 JavaThread* thr = java_lang_Thread::thread(java_thread);
1229 if (thr != NULL) {
1230 p = thr->parker();
1231 if (p != NULL) { // Bind to Java thread for next time.
1232 java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1233 }
1234 }
1235 }
1236 }
1237 }
1238 }
1239 if (p != NULL) {
1240 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1241 p->unpark();
1242 }
1243 UNSAFE_END
1244
1245 UNSAFE_ENTRY(jint, Unsafe_Loadavg(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem))
1246 UnsafeWrapper("Unsafe_Loadavg");
1247 const int max_nelem = 3;
1248 double la[max_nelem];
1249 jint ret;
1250
1251 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1252 assert(a->is_typeArray(), "must be type array");
1253
1254 if (nelem < 0 || nelem > max_nelem || a->length() < nelem) {
1255 ThreadToNativeFromVM ttnfv(thread);
1256 throw_new(env, "ArrayIndexOutOfBoundsException");
1257 return -1;
1258 }
1259
1260 ret = os::loadavg(la, nelem);
1261 if (ret == -1) return -1;
1262
1263 // if successful, ret is the number of samples actually retrieved.
1264 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1265 switch(ret) {
1266 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1267 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1268 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1269 }
1270 return ret;
1271 UNSAFE_END
1272
1273
1274 /// JVM_RegisterUnsafeMethods
1275
1276 #define ADR "J"
1277
1278 #define LANG "Ljava/lang/"
1279
1280 #define OBJ LANG "Object;"
1281 #define CLS LANG "Class;"
1282 #define FLD LANG "reflect/Field;"
1283 #define THR LANG "Throwable;"
1284
1285 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1286 #define DAC_Args CLS "[B[" OBJ
1287
1288 #define CC (char*) /*cast a literal from (const char*)*/
1289 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1290
1291 #define DECLARE_GETPUTOOP(Boolean, Z) \
1292 {CC "get" #Boolean, CC "(" OBJ "J)" #Z, FN_PTR(Unsafe_Get##Boolean)}, \
1293 {CC "put" #Boolean, CC "(" OBJ "J" #Z ")V", FN_PTR(Unsafe_Set##Boolean)}, \
1294 {CC "get" #Boolean "Volatile", CC "(" OBJ "J)" #Z, FN_PTR(Unsafe_Get##Boolean##Volatile)}, \
1295 {CC "put" #Boolean "Volatile", CC "(" OBJ "J" #Z ")V", FN_PTR(Unsafe_Set##Boolean##Volatile)}
1296
1297
1298 #define DECLARE_GETPUTNATIVE(Byte, B) \
1299 {CC "get" #Byte, CC "(" ADR ")" #B, FN_PTR(Unsafe_GetNative##Byte)}, \
1300 {CC "put" #Byte, CC "(" ADR#B ")V", FN_PTR(Unsafe_SetNative##Byte)}
1301
1302
1303 static JNINativeMethod sun_misc_Unsafe_methods[] = {
1304 {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)},
1305 {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObject)},
1306 {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)},
1307 {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObjectVolatile)},
1308
1309 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1310 {CC "getJavaMirror", CC "(" ADR ")" CLS, FN_PTR(Unsafe_GetJavaMirror)},
1311 {CC "getKlassPointer", CC "(" OBJ ")" ADR, FN_PTR(Unsafe_GetKlassPointer)},
1312
1313 DECLARE_GETPUTOOP(Boolean, Z),
1314 DECLARE_GETPUTOOP(Byte, B),
1315 DECLARE_GETPUTOOP(Short, S),
1316 DECLARE_GETPUTOOP(Char, C),
1317 DECLARE_GETPUTOOP(Int, I),
1318 DECLARE_GETPUTOOP(Long, J),
1319 DECLARE_GETPUTOOP(Float, F),
1320 DECLARE_GETPUTOOP(Double, D),
1321
1322 DECLARE_GETPUTNATIVE(Byte, B),
1323 DECLARE_GETPUTNATIVE(Short, S),
1324 DECLARE_GETPUTNATIVE(Char, C),
1325 DECLARE_GETPUTNATIVE(Int, I),
1326 DECLARE_GETPUTNATIVE(Long, J),
1327 DECLARE_GETPUTNATIVE(Float, F),
1328 DECLARE_GETPUTNATIVE(Double, D),
1329
1330 {CC "getAddress", CC "(" ADR ")" ADR, FN_PTR(Unsafe_GetNativeAddress)},
1331 {CC "putAddress", CC "(" ADR "" ADR ")V", FN_PTR(Unsafe_SetNativeAddress)},
1332
1333 {CC "allocateMemory", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory)},
1334 {CC "reallocateMemory", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory)},
1335 {CC "freeMemory", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory)},
1336
1337 {CC "objectFieldOffset", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset)},
1338 {CC "staticFieldOffset", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset)},
1339 {CC "staticFieldBase", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBaseFromField)},
1340 {CC "ensureClassInitialized",CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized)},
1341 {CC "arrayBaseOffset", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset)},
1342 {CC "arrayIndexScale", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale)},
1343 {CC "addressSize", CC "()I", FN_PTR(Unsafe_AddressSize)},
1344 {CC "pageSize", CC "()I", FN_PTR(Unsafe_PageSize)},
1345
1346 {CC "defineClass", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass)},
1347 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1348 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1349 {CC "compareAndSwapObject", CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSwapObject)},
1350 {CC "compareAndSwapInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSwapInt)},
1351 {CC "compareAndSwapLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSwapLong)},
1352 {CC "putOrderedObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetOrderedObject)},
1353 {CC "putOrderedInt", CC "(" OBJ "JI)V", FN_PTR(Unsafe_SetOrderedInt)},
1354 {CC "putOrderedLong", CC "(" OBJ "JJ)V", FN_PTR(Unsafe_SetOrderedLong)},
1355 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1356 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1357
1358 {CC "getLoadAverage", CC "([DI)I", FN_PTR(Unsafe_Loadavg)},
1359
1360 {CC "copyMemory", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory)},
1361 {CC "setMemory", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory)},
1362
1363 {CC "defineAnonymousClass", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass)},
1364
1365 {CC "shouldBeInitialized",CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized)},
1366
1367 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1368 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1369 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1370 };
1371
1372 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1373 {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)},
1374 {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObject)},
1375 {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)},
1376 {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObjectVolatile)},
1377
1378 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1379 {CC "getJavaMirror", CC "(" ADR ")" CLS, FN_PTR(Unsafe_GetJavaMirror)},
1380 {CC "getKlassPointer", CC "(" OBJ ")" ADR, FN_PTR(Unsafe_GetKlassPointer)},
1381
1382 DECLARE_GETPUTOOP(Boolean, Z),
1383 DECLARE_GETPUTOOP(Byte, B),
1384 DECLARE_GETPUTOOP(Short, S),
1385 DECLARE_GETPUTOOP(Char, C),
1386 DECLARE_GETPUTOOP(Int, I),
1387 DECLARE_GETPUTOOP(Long, J),
1388 DECLARE_GETPUTOOP(Float, F),
1389 DECLARE_GETPUTOOP(Double, D),
1390
1391 DECLARE_GETPUTNATIVE(Byte, B),
1392 DECLARE_GETPUTNATIVE(Short, S),
1393 DECLARE_GETPUTNATIVE(Char, C),
1394 DECLARE_GETPUTNATIVE(Int, I),
1395 DECLARE_GETPUTNATIVE(Long, J),
1396 DECLARE_GETPUTNATIVE(Float, F),
1397 DECLARE_GETPUTNATIVE(Double, D),
1398
1399 {CC "getAddress", CC "(" ADR ")" ADR, FN_PTR(Unsafe_GetNativeAddress)},
1400 {CC "putAddress", CC "(" ADR "" ADR ")V", FN_PTR(Unsafe_SetNativeAddress)},
1401
1402 {CC "allocateMemory", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory)},
1403 {CC "reallocateMemory", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory)},
1404 {CC "freeMemory", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory)},
1405
1406 {CC "objectFieldOffset", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset)},
1407 {CC "staticFieldOffset", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset)},
1408 {CC "staticFieldBase", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBaseFromField)},
1409 {CC "ensureClassInitialized",CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized)},
1410 {CC "arrayBaseOffset", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset)},
1411 {CC "arrayIndexScale", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale)},
1412 {CC "addressSize", CC "()I", FN_PTR(Unsafe_AddressSize)},
1413 {CC "pageSize", CC "()I", FN_PTR(Unsafe_PageSize)},
1414
1415 {CC "defineClass", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass)},
1416 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1417 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1418 {CC "compareAndSwapObject", CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSwapObject)},
1419 {CC "compareAndSwapInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSwapInt)},
1420 {CC "compareAndSwapLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSwapLong)},
1421 {CC "putOrderedObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetOrderedObject)},
1422 {CC "putOrderedInt", CC "(" OBJ "JI)V", FN_PTR(Unsafe_SetOrderedInt)},
1423 {CC "putOrderedLong", CC "(" OBJ "JJ)V", FN_PTR(Unsafe_SetOrderedLong)},
1424 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1425 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1426
1427 {CC "getLoadAverage", CC "([DI)I", FN_PTR(Unsafe_Loadavg)},
1428
1429 {CC "copyMemory", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory)},
1430 {CC "copySwapMemory", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory)},
1431 {CC "setMemory", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory)},
1432
1433 {CC "defineAnonymousClass", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass)},
1434
1435 {CC "shouldBeInitialized",CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized)},
1436
1437 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1438 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1439 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1440
1441 {CC "isBigEndian0", CC "()Z", FN_PTR(Unsafe_isBigEndian0)},
1442 {CC "unalignedAccess0", CC "()Z", FN_PTR(Unsafe_unalignedAccess0)}
1443 };
1444
1445 #undef CC
1446 #undef FN_PTR
1447
1448 #undef ADR
1449 #undef LANG
1450 #undef OBJ
1451 #undef CLS
1452 #undef FLD
1453 #undef THR
1454 #undef DC_Args
1455 #undef DAC_Args
1456
1457 #undef DECLARE_GETPUTOOP
1458 #undef DECLARE_GETPUTNATIVE
1459
1460
1461 // These two functions are exported, used by NativeLookup.
1462 // The Unsafe_xxx functions above are called only from the interpreter.
1463 // The optimizer looks at names and signatures to recognize
1464 // individual functions.
1465
1466 JVM_ENTRY(void, JVM_RegisterSunMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass))
1467 UnsafeWrapper("JVM_RegisterSunMiscUnsafeMethods");
1468 {
1469 ThreadToNativeFromVM ttnfv(thread);
1470
1471 int ok = env->RegisterNatives(unsafeclass, sun_misc_Unsafe_methods, sizeof(sun_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1472 guarantee(ok == 0, "register sun.misc.Unsafe natives");
1473 }
1474 JVM_END
1475
1476 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass))
1477 UnsafeWrapper("JVM_RegisterJDKInternalMiscUnsafeMethods");
1478 {
1479 ThreadToNativeFromVM ttnfv(thread);
1480
1481 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1482 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1483 }
1484 JVM_END