1 /*
2 * Copyright (c) 2000, 2018, 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 "jni.h"
27 #include "jvm.h"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "jfr/jfrEvents.hpp"
31 #include "memory/allocation.inline.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "logging/log.hpp"
34 #include "oops/access.inline.hpp"
35 #include "oops/fieldStreams.hpp"
36 #include "oops/objArrayOop.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "oops/typeArrayOop.inline.hpp"
39 #include "oops/valueArrayKlass.hpp"
40 #include "oops/valueArrayOop.hpp"
41 #include "oops/valueArrayOop.inline.hpp"
42 #include "prims/unsafe.hpp"
43 #include "runtime/atomic.hpp"
44 #include "runtime/globals.hpp"
45 #include "runtime/interfaceSupport.inline.hpp"
46 #include "runtime/jniHandles.inline.hpp"
47 #include "runtime/orderAccess.inline.hpp"
48 #include "runtime/reflection.hpp"
49 #include "runtime/thread.hpp"
50 #include "runtime/threadSMR.hpp"
51 #include "runtime/vm_version.hpp"
52 #include "services/threadService.hpp"
53 #include "utilities/align.hpp"
54 #include "utilities/copy.hpp"
55 #include "utilities/dtrace.hpp"
56 #include "utilities/macros.hpp"
57
58 /**
59 * Implementation of the jdk.internal.misc.Unsafe class
60 */
61
62
63 #define MAX_OBJECT_SIZE \
64 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
65 + ((julong)max_jint * sizeof(double)) )
66
67
68 #define UNSAFE_ENTRY(result_type, header) \
69 JVM_ENTRY(static result_type, header)
70
71 #define UNSAFE_LEAF(result_type, header) \
72 JVM_LEAF(static result_type, header)
73
74 #define UNSAFE_END JVM_END
75
76
77 static 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 static 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 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
102 return field_offset;
103 }
104
105 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
106 return byte_offset;
107 }
108
109 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
110 #ifdef ASSERT
111 jlong byte_offset = field_offset_to_byte_offset(field_offset);
112
113 if (p != NULL) {
114 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
115 if (byte_offset == (jint)byte_offset) {
116 void* ptr_plus_disp = (address)p + byte_offset;
117 assert(p->field_addr_raw((jint)byte_offset) == ptr_plus_disp,
118 "raw [ptr+disp] must be consistent with oop::field_addr_raw");
119 }
120 jlong p_size = HeapWordSize * (jlong)(p->size());
121 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
122 }
123 #endif
124 }
125
126 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
127 assert_field_offset_sane(p, field_offset);
128 jlong byte_offset = field_offset_to_byte_offset(field_offset);
129
130 if (p != NULL) {
131 p = Access<>::resolve(p);
132 }
133
134 if (sizeof(char*) == sizeof(jint)) { // (this constant folds!)
135 return (address)p + (jint) byte_offset;
136 } else {
137 return (address)p + byte_offset;
138 }
139 }
140
141 // Externally callable versions:
142 // (Use these in compiler intrinsics which emulate unsafe primitives.)
143 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
144 return field_offset;
145 }
146 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
147 return byte_offset;
148 }
149
150
151 ///// Data read/writes on the Java heap and in native (off-heap) memory
152
153 /**
154 * Helper class for accessing memory.
155 *
156 * Normalizes values and wraps accesses in
157 * JavaThread::doing_unsafe_access() if needed.
158 */
159 template <typename T>
160 class MemoryAccess : StackObj {
161 JavaThread* _thread;
162 oop _obj;
163 ptrdiff_t _offset;
164
165 // Resolves and returns the address of the memory access.
166 // This raw memory access may fault, so we make sure it happens within the
167 // guarded scope by making the access volatile at least. Since the store
168 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
169 // can not be reordered by the compiler. Therefore, if the access triggers
170 // a fault, we will know that Thread::doing_unsafe_access() returns true.
171 volatile T* addr() {
172 void* addr = index_oop_from_field_offset_long(_obj, _offset);
173 return static_cast<volatile T*>(addr);
174 }
175
176 template <typename U>
177 U normalize_for_write(U x) {
178 return x;
179 }
180
181 jboolean normalize_for_write(jboolean x) {
182 return x & 1;
183 }
184
185 template <typename U>
186 U normalize_for_read(U x) {
187 return x;
188 }
189
190 jboolean normalize_for_read(jboolean x) {
191 return x != 0;
192 }
193
194 /**
195 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
196 */
197 class GuardUnsafeAccess {
198 JavaThread* _thread;
199
200 public:
201 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
202 // native/off-heap access which may raise SIGBUS if accessing
203 // memory mapped file data in a region of the file which has
204 // been truncated and is now invalid
205 _thread->set_doing_unsafe_access(true);
206 }
207
208 ~GuardUnsafeAccess() {
209 _thread->set_doing_unsafe_access(false);
210 }
211 };
212
213 public:
214 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
215 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
216 assert_field_offset_sane(_obj, offset);
217 }
218
219 T get() {
220 if (_obj == NULL) {
221 GuardUnsafeAccess guard(_thread);
222 T ret = RawAccess<>::load(addr());
223 return normalize_for_read(ret);
224 } else {
225 T ret = HeapAccess<>::load_at(_obj, _offset);
226 return normalize_for_read(ret);
227 }
228 }
229
230 void put(T x) {
231 if (_obj == NULL) {
232 GuardUnsafeAccess guard(_thread);
233 RawAccess<>::store(addr(), normalize_for_write(x));
234 } else {
235 HeapAccess<>::store_at(_obj, _offset, normalize_for_write(x));
236 }
237 }
238
239
240 T get_volatile() {
241 if (_obj == NULL) {
242 GuardUnsafeAccess guard(_thread);
243 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
244 return normalize_for_read(ret);
245 } else {
246 T ret = HeapAccess<MO_SEQ_CST>::load_at(_obj, _offset);
247 return normalize_for_read(ret);
248 }
249 }
250
251 void put_volatile(T x) {
252 if (_obj == NULL) {
253 GuardUnsafeAccess guard(_thread);
254 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
255 } else {
256 HeapAccess<MO_SEQ_CST>::store_at(_obj, _offset, normalize_for_write(x));
257 }
258 }
259 };
260
261 #ifdef ASSERT
262 /*
263 * Get the field descriptor of the field of the given object at the given offset.
264 */
265 static bool get_field_descriptor(oop p, jlong offset, fieldDescriptor* fd) {
266 bool found = false;
267 Klass* k = p->klass();
268 if (k->is_instance_klass()) {
269 InstanceKlass* ik = InstanceKlass::cast(k);
270 found = ik->find_field_from_offset((int)offset, false, fd);
271 if (!found && ik->is_mirror_instance_klass()) {
272 Klass* k2 = java_lang_Class::as_Klass(p);
273 if (k2->is_instance_klass()) {
274 ik = InstanceKlass::cast(k2);
275 found = ik->find_field_from_offset((int)offset, true, fd);
276 }
277 }
278 }
279 return found;
280 }
281 #endif // ASSERT
282
283 // These functions allow a null base pointer with an arbitrary address.
284 // But if the base pointer is non-null, the offset should make some sense.
285 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
286 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
287 oop p = JNIHandles::resolve(obj);
288 assert_field_offset_sane(p, offset);
289 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
290 return JNIHandles::make_local(env, v);
291 } UNSAFE_END
292
293 UNSAFE_ENTRY(void, Unsafe_PutObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
294 oop x = JNIHandles::resolve(x_h);
295 oop p = JNIHandles::resolve(obj);
296 assert_field_offset_sane(p, offset);
297 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
298 } UNSAFE_END
299
300 UNSAFE_ENTRY(jobject, Unsafe_GetValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass c)) {
301 oop p = JNIHandles::resolve(obj);
302 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
303 ValueKlass* vk = ValueKlass::cast(k);
304
305 #ifdef ASSERT
306 Klass* ok = p->klass();
307 if (ok->is_instance_klass()) {
308 assert_field_offset_sane(p, offset);
309 fieldDescriptor fd;
310 bool found = get_field_descriptor(p, offset, &fd);
311 assert(found, "value field not found");
312 assert(fd.is_flattened(), "field not flat");
313 } else if (ok->is_valueArray_klass()) {
314 ValueArrayKlass* vak = ValueArrayKlass::cast(ok);
315 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
316 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
317 assert(dest == ((address)p) + offset, "invalid offset");
318 }
319 #endif // ASSERT
320
321 if (log_is_enabled(Trace, valuetypes)) {
322 if (p->klass()->is_valueArray_klass()) {
323 ValueArrayKlass* vak = ValueArrayKlass::cast(p->klass());
324 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
325 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
326 log_trace(valuetypes)("getValue: array type %s index %d element size %d offset " SIZE_FORMAT_HEX " at " INTPTR_FORMAT,
327 vak->external_name(), index, vak->element_byte_size(), offset, p2i(dest));
328 } else {
329 log_trace(valuetypes)("getValue: field type %s at offset " SIZE_FORMAT_HEX,
330 vk->external_name(), offset);
331 }
332 }
333
334 Handle p_h(THREAD, p);
335 bool in_heap;
336 oop v = vk->allocate_buffered_or_heap_instance(&in_heap, CHECK_NULL); // allocate instance
337 vk->initialize(CHECK_NULL); // If field is a default value, value class might not be initialized yet
338 vk->value_store(((char*)(oopDesc*)p_h()) + offset,
339 vk->data_for_oop(v),
340 in_heap, true);
341 return JNIHandles::make_local(env, v);
342 } UNSAFE_END
343
344 UNSAFE_ENTRY(void, Unsafe_PutValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass c, jobject value)) {
345 oop v = JNIHandles::resolve(value);
346 oop p = JNIHandles::resolve(obj);
347 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
348 ValueKlass* vk = ValueKlass::cast(k);
349
350 #ifdef ASSERT
351 Klass* ok = p->klass();
352 if (ok->is_instance_klass()) {
353 assert_field_offset_sane(p, offset);
354 fieldDescriptor fd;
355 bool found = get_field_descriptor(p, offset, &fd);
356 assert(found, "value field not found");
357 assert(fd.is_flattened(), "field not flat");
358 } else if (ok->is_valueArray_klass()) {
359 ValueArrayKlass* vak = ValueArrayKlass::cast(ok);
360 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
361 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
362 assert(dest == ((address)p) + offset, "invalid offset");
363 }
364 #endif // ASSERT
365
366 if (log_is_enabled(Trace, valuetypes)) {
367 if (p->klass()->is_valueArray_klass()) {
368 ValueArrayKlass* vak = ValueArrayKlass::cast(p->klass());
369 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
370 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
371 log_trace(valuetypes)("putValue: array type %s index %d element size %d offset " SIZE_FORMAT_HEX " at " INTPTR_FORMAT,
372 vak->external_name(), index, vak->element_byte_size(), offset, p2i(dest));
373 } else {
374 log_trace(valuetypes)("putValue: field type %s at offset " SIZE_FORMAT_HEX,
375 vk->external_name(), offset);
376 }
377 }
378 vk->value_store(vk->data_for_oop(v),
379 ((char*)(oopDesc*)p) + offset, true, true);
380 } UNSAFE_END
381
382 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
383 oop p = JNIHandles::resolve(obj);
384 assert_field_offset_sane(p, offset);
385 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
386 return JNIHandles::make_local(env, v);
387 } UNSAFE_END
388
389 UNSAFE_ENTRY(void, Unsafe_PutObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
390 oop x = JNIHandles::resolve(x_h);
391 oop p = JNIHandles::resolve(obj);
392 assert_field_offset_sane(p, offset);
393 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
394 } UNSAFE_END
395
396 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
397 oop v = *(oop*) (address) addr;
398 return JNIHandles::make_local(env, v);
399 } UNSAFE_END
400
401 UNSAFE_LEAF(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe)) {
402 #ifdef VM_LITTLE_ENDIAN
403 return false;
404 #else
405 return true;
406 #endif
407 } UNSAFE_END
408
409 UNSAFE_LEAF(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe)) {
410 return UseUnalignedAccesses;
411 } UNSAFE_END
412
413 #define DEFINE_GETSETOOP(java_type, Type) \
414 \
415 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
416 return MemoryAccess<java_type>(thread, obj, offset).get(); \
417 } UNSAFE_END \
418 \
419 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
420 MemoryAccess<java_type>(thread, obj, offset).put(x); \
421 } UNSAFE_END \
422 \
423 // END DEFINE_GETSETOOP.
424
425 DEFINE_GETSETOOP(jboolean, Boolean)
426 DEFINE_GETSETOOP(jbyte, Byte)
427 DEFINE_GETSETOOP(jshort, Short);
428 DEFINE_GETSETOOP(jchar, Char);
429 DEFINE_GETSETOOP(jint, Int);
430 DEFINE_GETSETOOP(jlong, Long);
431 DEFINE_GETSETOOP(jfloat, Float);
432 DEFINE_GETSETOOP(jdouble, Double);
433
434 #undef DEFINE_GETSETOOP
435
436 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
437 \
438 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
439 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
440 } UNSAFE_END \
441 \
442 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
443 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
444 } UNSAFE_END \
445 \
446 // END DEFINE_GETSETOOP_VOLATILE.
447
448 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
449 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
450 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
451 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
452 DEFINE_GETSETOOP_VOLATILE(jint, Int);
453 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
454 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
455 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
456
457 #undef DEFINE_GETSETOOP_VOLATILE
458
459 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
460 OrderAccess::acquire();
461 } UNSAFE_END
462
463 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
464 OrderAccess::release();
465 } UNSAFE_END
466
467 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
468 OrderAccess::fence();
469 } UNSAFE_END
470
471 ////// Allocation requests
472
473 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
474 ThreadToNativeFromVM ttnfv(thread);
475 return env->AllocObject(cls);
476 } UNSAFE_END
477
478 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
479 size_t sz = (size_t)size;
480
481 sz = align_up(sz, HeapWordSize);
482 void* x = os::malloc(sz, mtOther);
483
484 return addr_to_java(x);
485 } UNSAFE_END
486
487 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
488 void* p = addr_from_java(addr);
489 size_t sz = (size_t)size;
490 sz = align_up(sz, HeapWordSize);
491
492 void* x = os::realloc(p, sz, mtOther);
493
494 return addr_to_java(x);
495 } UNSAFE_END
496
497 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
498 void* p = addr_from_java(addr);
499
500 os::free(p);
501 } UNSAFE_END
502
503 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
504 size_t sz = (size_t)size;
505
506 oop base = JNIHandles::resolve(obj);
507 void* p = index_oop_from_field_offset_long(base, offset);
508
509 Copy::fill_to_memory_atomic(p, sz, value);
510 } UNSAFE_END
511
512 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
513 size_t sz = (size_t)size;
514
515 oop srcp = JNIHandles::resolve(srcObj);
516 oop dstp = JNIHandles::resolve(dstObj);
517
518 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
519 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
520
521 Copy::conjoint_memory_atomic(src, dst, sz);
522 } UNSAFE_END
523
524 // This function is a leaf since if the source and destination are both in native memory
525 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
526 // If either source or destination (or both) are on the heap, the function will enter VM using
527 // JVM_ENTRY_FROM_LEAF
528 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
529 size_t sz = (size_t)size;
530 size_t esz = (size_t)elemSize;
531
532 if (srcObj == NULL && dstObj == NULL) {
533 // Both src & dst are in native memory
534 address src = (address)srcOffset;
535 address dst = (address)dstOffset;
536
537 Copy::conjoint_swap(src, dst, sz, esz);
538 } else {
539 // At least one of src/dst are on heap, transition to VM to access raw pointers
540
541 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
542 oop srcp = JNIHandles::resolve(srcObj);
543 oop dstp = JNIHandles::resolve(dstObj);
544
545 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
546 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
547
548 Copy::conjoint_swap(src, dst, sz, esz);
549 } JVM_END
550 }
551 } UNSAFE_END
552
553 ////// Random queries
554
555 UNSAFE_LEAF(jint, Unsafe_AddressSize0(JNIEnv *env, jobject unsafe)) {
556 return sizeof(void*);
557 } UNSAFE_END
558
559 UNSAFE_LEAF(jint, Unsafe_PageSize()) {
560 return os::vm_page_size();
561 } UNSAFE_END
562
563 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
564 assert(clazz != NULL, "clazz must not be NULL");
565 assert(name != NULL, "name must not be NULL");
566
567 ResourceMark rm(THREAD);
568 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
569
570 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
571
572 jint offset = -1;
573 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
574 Symbol *name = fs.name();
575 if (name->equals(utf_name)) {
576 offset = fs.offset();
577 break;
578 }
579 }
580 if (offset < 0) {
581 THROW_0(vmSymbols::java_lang_InternalError());
582 }
583 return field_offset_from_byte_offset(offset);
584 }
585
586 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
587 assert(field != NULL, "field must not be NULL");
588
589 oop reflected = JNIHandles::resolve_non_null(field);
590 oop mirror = java_lang_reflect_Field::clazz(reflected);
591 Klass* k = java_lang_Class::as_Klass(mirror);
592 int slot = java_lang_reflect_Field::slot(reflected);
593 int modifiers = java_lang_reflect_Field::modifiers(reflected);
594
595 if (must_be_static >= 0) {
596 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
597 if (must_be_static != really_is_static) {
598 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
599 }
600 }
601
602 int offset = InstanceKlass::cast(k)->field_offset(slot);
603 return field_offset_from_byte_offset(offset);
604 }
605
606 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
607 return find_field_offset(field, 0, THREAD);
608 } UNSAFE_END
609
610 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
611 return find_field_offset(c, name, THREAD);
612 } UNSAFE_END
613
614 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
615 return find_field_offset(field, 1, THREAD);
616 } UNSAFE_END
617
618 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
619 assert(field != NULL, "field must not be NULL");
620
621 // Note: In this VM implementation, a field address is always a short
622 // offset from the base of a a klass metaobject. Thus, the full dynamic
623 // range of the return type is never used. However, some implementations
624 // might put the static field inside an array shared by many classes,
625 // or even at a fixed address, in which case the address could be quite
626 // large. In that last case, this function would return NULL, since
627 // the address would operate alone, without any base pointer.
628
629 oop reflected = JNIHandles::resolve_non_null(field);
630 oop mirror = java_lang_reflect_Field::clazz(reflected);
631 int modifiers = java_lang_reflect_Field::modifiers(reflected);
632
633 if ((modifiers & JVM_ACC_STATIC) == 0) {
634 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
635 }
636
637 return JNIHandles::make_local(env, mirror);
638 } UNSAFE_END
639
640 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
641 assert(clazz != NULL, "clazz must not be NULL");
642
643 oop mirror = JNIHandles::resolve_non_null(clazz);
644
645 Klass* klass = java_lang_Class::as_Klass(mirror);
646 if (klass != NULL && klass->should_be_initialized()) {
647 InstanceKlass* k = InstanceKlass::cast(klass);
648 k->initialize(CHECK);
649 }
650 }
651 UNSAFE_END
652
653 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
654 assert(clazz != NULL, "clazz must not be NULL");
655
656 oop mirror = JNIHandles::resolve_non_null(clazz);
657 Klass* klass = java_lang_Class::as_Klass(mirror);
658
659 if (klass != NULL && klass->should_be_initialized()) {
660 return true;
661 }
662
663 return false;
664 }
665 UNSAFE_END
666
667 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
668 assert(clazz != NULL, "clazz must not be NULL");
669
670 oop mirror = JNIHandles::resolve_non_null(clazz);
671 Klass* k = java_lang_Class::as_Klass(mirror);
672
673 if (k == NULL || !k->is_array_klass()) {
674 THROW(vmSymbols::java_lang_InvalidClassException());
675 } else if (k->is_objArray_klass()) {
676 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
677 scale = heapOopSize;
678 } else if (k->is_typeArray_klass()) {
679 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
680 base = tak->array_header_in_bytes();
681 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
682 scale = (1 << tak->log2_element_size());
683 } else if (k->is_valueArray_klass()) {
684 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
685 ValueKlass* vklass = vak->element_klass();
686 base = vak->array_header_in_bytes();
687 scale = vak->element_byte_size();
688 } else {
689 ShouldNotReachHere();
690 }
691 }
692
693 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
694 int base = 0, scale = 0;
695 getBaseAndScale(base, scale, clazz, CHECK_0);
696
697 return field_offset_from_byte_offset(base);
698 } UNSAFE_END
699
700
701 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
702 int base = 0, scale = 0;
703 getBaseAndScale(base, scale, clazz, CHECK_0);
704
705 // This VM packs both fields and array elements down to the byte.
706 // But watch out: If this changes, so that array references for
707 // a given primitive type (say, T_BOOLEAN) use different memory units
708 // than fields, this method MUST return zero for such arrays.
709 // For example, the VM used to store sub-word sized fields in full
710 // words in the object layout, so that accessors like getByte(Object,int)
711 // did not really do what one might expect for arrays. Therefore,
712 // this function used to report a zero scale factor, so that the user
713 // would know not to attempt to access sub-word array elements.
714 // // Code for unpacked fields:
715 // if (scale < wordSize) return 0;
716
717 // The following allows for a pretty general fieldOffset cookie scheme,
718 // but requires it to be linear in byte offset.
719 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
720 } UNSAFE_END
721
722
723 static inline void throw_new(JNIEnv *env, const char *ename) {
724 jclass cls = env->FindClass(ename);
725 if (env->ExceptionCheck()) {
726 env->ExceptionClear();
727 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
728 return;
729 }
730
731 env->ThrowNew(cls, NULL);
732 }
733
734 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
735 // Code lifted from JDK 1.3 ClassLoader.c
736
737 jbyte *body;
738 char *utfName = NULL;
739 jclass result = 0;
740 char buf[128];
741
742 assert(data != NULL, "Class bytes must not be NULL");
743 assert(length >= 0, "length must not be negative: %d", length);
744
745 if (UsePerfData) {
746 ClassLoader::unsafe_defineClassCallCounter()->inc();
747 }
748
749 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
750 if (body == NULL) {
751 throw_new(env, "java/lang/OutOfMemoryError");
752 return 0;
753 }
754
755 env->GetByteArrayRegion(data, offset, length, body);
756 if (env->ExceptionOccurred()) {
757 goto free_body;
758 }
759
760 if (name != NULL) {
761 uint len = env->GetStringUTFLength(name);
762 int unicode_len = env->GetStringLength(name);
763
764 if (len >= sizeof(buf)) {
765 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
766 if (utfName == NULL) {
767 throw_new(env, "java/lang/OutOfMemoryError");
768 goto free_body;
769 }
770 } else {
771 utfName = buf;
772 }
773
774 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
775
776 for (uint i = 0; i < len; i++) {
777 if (utfName[i] == '.') utfName[i] = '/';
778 }
779 }
780
781 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
782
783 if (utfName && utfName != buf) {
784 FREE_C_HEAP_ARRAY(char, utfName);
785 }
786
787 free_body:
788 FREE_C_HEAP_ARRAY(jbyte, body);
789 return result;
790 }
791
792
793 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
794 ThreadToNativeFromVM ttnfv(thread);
795
796 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
797 } UNSAFE_END
798
799
800 // define a class but do not make it known to the class loader or system dictionary
801 // - host_class: supplies context for linkage, access control, protection domain, and class loader
802 // if host_class is itself anonymous then it is replaced with its host class.
803 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
804 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
805
806 // When you load an anonymous class U, it works as if you changed its name just before loading,
807 // to a name that you will never use again. Since the name is lost, no other class can directly
808 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
809 // through java.lang.Class methods like Class.newInstance.
810
811 // The package of an anonymous class must either match its host's class's package or be in the
812 // unnamed package. If it is in the unnamed package then it will be put in its host class's
813 // package.
814 //
815
816 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
817 // An anonymous class also has special privileges to access any member of its host class.
818 // This is the main reason why this loading operation is unsafe. The purpose of this is to
819 // allow language implementations to simulate "open classes"; a host class in effect gets
820 // new code when an anonymous class is loaded alongside it. A less convenient but more
821 // standard way to do this is with reflection, which can also be set to ignore access
822 // restrictions.
823
824 // Access into an anonymous class is possible only through reflection. Therefore, there
825 // are no special access rules for calling into an anonymous class. The relaxed access
826 // rule for the host class is applied in the opposite direction: A host class reflectively
827 // access one of its anonymous classes.
828
829 // If you load the same bytecodes twice, you get two different classes. You can reload
830 // the same bytecodes with or without varying CP patches.
831
832 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
833 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
834 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
835
836 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
837 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
838 // It is not possible for a named class, or an older anonymous class, to refer by
839 // name (via its CP) to a newer anonymous class.
840
841 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
842 // or type descriptors used in the loaded anonymous class.
843
844 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
845 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
846 // be changed to println(greeting), where greeting is an arbitrary object created before
847 // the anonymous class is loaded. This is useful in dynamic languages, in which
848 // various kinds of metaobjects must be introduced as constants into bytecode.
849 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
850 // not just a literal string. For such ldc instructions, the verifier uses the
851 // type Object instead of String, if the loaded constant is not in fact a String.
852
853 static InstanceKlass*
854 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
855 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
856 u1** temp_alloc,
857 TRAPS) {
858 assert(host_class != NULL, "host_class must not be NULL");
859 assert(data != NULL, "data must not be NULL");
860
861 if (UsePerfData) {
862 ClassLoader::unsafe_defineClassCallCounter()->inc();
863 }
864
865 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
866 assert(length >= 0, "class_bytes_length must not be negative: %d", length);
867
868 int class_bytes_length = (int) length;
869
870 u1* class_bytes = NEW_C_HEAP_ARRAY(u1, length, mtInternal);
871 if (class_bytes == NULL) {
872 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
873 }
874
875 // caller responsible to free it:
876 *temp_alloc = class_bytes;
877
878 jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0);
879 Copy::conjoint_jbytes(array_base, class_bytes, length);
880
881 objArrayHandle cp_patches_h;
882 if (cp_patches_jh != NULL) {
883 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
884 assert(p->is_objArray(), "cp_patches must be an object[]");
885 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
886 }
887
888 const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
889
890 // Make sure it's the real host class, not another anonymous class.
891 while (host_klass != NULL && host_klass->is_instance_klass() &&
892 InstanceKlass::cast(host_klass)->is_anonymous()) {
893 host_klass = InstanceKlass::cast(host_klass)->host_klass();
894 }
895
896 // Primitive types have NULL Klass* fields in their java.lang.Class instances.
897 if (host_klass == NULL) {
898 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
899 }
900
901 assert(host_klass->is_instance_klass(), "Host class must be an instance class");
902
903 const char* host_source = host_klass->external_name();
904 Handle host_loader(THREAD, host_klass->class_loader());
905 Handle host_domain(THREAD, host_klass->protection_domain());
906
907 GrowableArray<Handle>* cp_patches = NULL;
908
909 if (cp_patches_h.not_null()) {
910 int alen = cp_patches_h->length();
911
912 for (int i = alen-1; i >= 0; i--) {
913 oop p = cp_patches_h->obj_at(i);
914 if (p != NULL) {
915 Handle patch(THREAD, p);
916
917 if (cp_patches == NULL) {
918 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
919 }
920
921 cp_patches->at_put(i, patch);
922 }
923 }
924 }
925
926 ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
927
928 Symbol* no_class_name = NULL;
929 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
930 host_loader,
931 host_domain,
932 &st,
933 InstanceKlass::cast(host_klass),
934 cp_patches,
935 CHECK_NULL);
936 if (anonk == NULL) {
937 return NULL;
938 }
939
940 return InstanceKlass::cast(anonk);
941 }
942
943 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
944 ResourceMark rm(THREAD);
945
946 jobject res_jh = NULL;
947 u1* temp_alloc = NULL;
948
949 InstanceKlass* anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
950 if (anon_klass != NULL) {
951 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
952 }
953
954 // try/finally clause:
955 if (temp_alloc != NULL) {
956 FREE_C_HEAP_ARRAY(u1, temp_alloc);
957 }
958
959 // The anonymous class loader data has been artificially been kept alive to
960 // this point. The mirror and any instances of this class have to keep
961 // it alive afterwards.
962 if (anon_klass != NULL) {
963 anon_klass->class_loader_data()->dec_keep_alive();
964 }
965
966 // let caller initialize it as needed...
967
968 return (jclass) res_jh;
969 } UNSAFE_END
970
971
972
973 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
974 ThreadToNativeFromVM ttnfv(thread);
975 env->Throw(thr);
976 } UNSAFE_END
977
978 // JSR166 ------------------------------------------------------------------
979
980 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
981 oop x = JNIHandles::resolve(x_h);
982 oop e = JNIHandles::resolve(e_h);
983 oop p = JNIHandles::resolve(obj);
984 assert_field_offset_sane(p, offset);
985 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
986 return JNIHandles::make_local(env, res);
987 } UNSAFE_END
988
989 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
990 oop p = JNIHandles::resolve(obj);
991 if (p == NULL) {
992 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
993 return RawAccess<>::atomic_cmpxchg(x, addr, e);
994 } else {
995 assert_field_offset_sane(p, offset);
996 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
997 }
998 } UNSAFE_END
999
1000 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1001 oop p = JNIHandles::resolve(obj);
1002 if (p == NULL) {
1003 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1004 return RawAccess<>::atomic_cmpxchg(x, addr, e);
1005 } else {
1006 assert_field_offset_sane(p, offset);
1007 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1008 }
1009 } UNSAFE_END
1010
1011 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1012 oop x = JNIHandles::resolve(x_h);
1013 oop e = JNIHandles::resolve(e_h);
1014 oop p = JNIHandles::resolve(obj);
1015 assert_field_offset_sane(p, offset);
1016 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1017 return oopDesc::equals(ret, e);
1018 } UNSAFE_END
1019
1020 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1021 oop p = JNIHandles::resolve(obj);
1022 if (p == NULL) {
1023 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1024 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
1025 } else {
1026 assert_field_offset_sane(p, offset);
1027 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
1028 }
1029 } UNSAFE_END
1030
1031 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1032 oop p = JNIHandles::resolve(obj);
1033 if (p == NULL) {
1034 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1035 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
1036 } else {
1037 assert_field_offset_sane(p, offset);
1038 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
1039 }
1040 } UNSAFE_END
1041
1042 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout) {
1043 assert(event != NULL, "invariant");
1044 assert(event->should_commit(), "invariant");
1045 event->set_parkedClass((obj != NULL) ? obj->klass() : NULL);
1046 event->set_timeout(timeout);
1047 event->set_address((obj != NULL) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1048 event->commit();
1049 }
1050
1051 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1052 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1053 EventThreadPark event;
1054
1055 JavaThreadParkedState jtps(thread, time != 0);
1056 thread->parker()->park(isAbsolute != 0, time);
1057 if (event.should_commit()) {
1058 post_thread_park_event(&event, thread->current_park_blocker(), time);
1059 }
1060 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1061 } UNSAFE_END
1062
1063 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1064 Parker* p = NULL;
1065
1066 if (jthread != NULL) {
1067 ThreadsListHandle tlh;
1068 JavaThread* thr = NULL;
1069 oop java_thread = NULL;
1070 (void) tlh.cv_internal_thread_to_JavaThread(jthread, &thr, &java_thread);
1071 if (java_thread != NULL) {
1072 // This is a valid oop.
1073 jlong lp = java_lang_Thread::park_event(java_thread);
1074 if (lp != 0) {
1075 // This cast is OK even though the jlong might have been read
1076 // non-atomically on 32bit systems, since there, one word will
1077 // always be zero anyway and the value set is always the same
1078 p = (Parker*)addr_from_java(lp);
1079 } else {
1080 // Not cached in the java.lang.Thread oop yet (could be an
1081 // older version of library).
1082 if (thr != NULL) {
1083 // The JavaThread is alive.
1084 p = thr->parker();
1085 if (p != NULL) {
1086 // Cache the Parker in the java.lang.Thread oop for next time.
1087 java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1088 }
1089 }
1090 }
1091 }
1092 } // ThreadsListHandle is destroyed here.
1093
1094 if (p != NULL) {
1095 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1096 p->unpark();
1097 }
1098 } UNSAFE_END
1099
1100 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1101 const int max_nelem = 3;
1102 double la[max_nelem];
1103 jint ret;
1104
1105 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1106 assert(a->is_typeArray(), "must be type array");
1107
1108 ret = os::loadavg(la, nelem);
1109 if (ret == -1) {
1110 return -1;
1111 }
1112
1113 // if successful, ret is the number of samples actually retrieved.
1114 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1115 switch(ret) {
1116 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1117 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1118 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1119 }
1120
1121 return ret;
1122 } UNSAFE_END
1123
1124
1125 /// JVM_RegisterUnsafeMethods
1126
1127 #define ADR "J"
1128
1129 #define LANG "Ljava/lang/"
1130
1131 #define OBJ LANG "Object;"
1132 #define CLS LANG "Class;"
1133 #define FLD LANG "reflect/Field;"
1134 #define THR LANG "Throwable;"
1135
1136 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1137 #define DAC_Args CLS "[B[" OBJ
1138
1139 #define CC (char*) /*cast a literal from (const char*)*/
1140 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1141
1142 #define DECLARE_GETPUTOOP(Type, Desc) \
1143 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1144 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1145 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1146 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1147
1148
1149 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1150 {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)},
1151 {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObject)},
1152 {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)},
1153 {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObjectVolatile)},
1154
1155 {CC "getValue", CC "(" OBJ "J" CLS ")" OBJ "", FN_PTR(Unsafe_GetValue)},
1156 {CC "putValue", CC "(" OBJ "J" CLS OBJ ")V", FN_PTR(Unsafe_PutValue)},
1157
1158 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1159
1160 DECLARE_GETPUTOOP(Boolean, Z),
1161 DECLARE_GETPUTOOP(Byte, B),
1162 DECLARE_GETPUTOOP(Short, S),
1163 DECLARE_GETPUTOOP(Char, C),
1164 DECLARE_GETPUTOOP(Int, I),
1165 DECLARE_GETPUTOOP(Long, J),
1166 DECLARE_GETPUTOOP(Float, F),
1167 DECLARE_GETPUTOOP(Double, D),
1168
1169 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1170 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1171 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1172
1173 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1174 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1175 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1176 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1177 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1178 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1179 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1180 {CC "addressSize0", CC "()I", FN_PTR(Unsafe_AddressSize0)},
1181 {CC "pageSize", CC "()I", FN_PTR(Unsafe_PageSize)},
1182
1183 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1184 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1185 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1186 {CC "compareAndSetObject",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetObject)},
1187 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1188 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1189 {CC "compareAndExchangeObject", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeObject)},
1190 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1191 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1192
1193 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1194 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1195
1196 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1197
1198 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1199 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1200 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1201
1202 {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1203
1204 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1205
1206 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1207 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1208 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1209
1210 {CC "isBigEndian0", CC "()Z", FN_PTR(Unsafe_isBigEndian0)},
1211 {CC "unalignedAccess0", CC "()Z", FN_PTR(Unsafe_unalignedAccess0)}
1212 };
1213
1214 #undef CC
1215 #undef FN_PTR
1216
1217 #undef ADR
1218 #undef LANG
1219 #undef OBJ
1220 #undef CLS
1221 #undef FLD
1222 #undef THR
1223 #undef DC_Args
1224 #undef DAC_Args
1225
1226 #undef DECLARE_GETPUTOOP
1227
1228
1229 // This function is exported, used by NativeLookup.
1230 // The Unsafe_xxx functions above are called only from the interpreter.
1231 // The optimizer looks at names and signatures to recognize
1232 // individual functions.
1233
1234 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1235 ThreadToNativeFromVM ttnfv(thread);
1236
1237 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1238 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1239 } JVM_END