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 "logging/logStream.hpp"
35 #include "oops/access.inline.hpp"
36 #include "oops/fieldStreams.hpp"
37 #include "oops/objArrayOop.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "oops/typeArrayOop.inline.hpp"
40 #include "oops/valueArrayKlass.hpp"
41 #include "oops/valueArrayOop.hpp"
42 #include "oops/valueArrayOop.inline.hpp"
43 #include "prims/unsafe.hpp"
44 #include "runtime/atomic.hpp"
45 #include "runtime/fieldDescriptor.inline.hpp"
46 #include "runtime/globals.hpp"
47 #include "runtime/interfaceSupport.inline.hpp"
48 #include "runtime/jniHandles.inline.hpp"
49 #include "runtime/orderAccess.hpp"
50 #include "runtime/reflection.hpp"
51 #include "runtime/thread.hpp"
52 #include "runtime/threadSMR.hpp"
53 #include "runtime/vm_version.hpp"
54 #include "services/threadService.hpp"
55 #include "utilities/align.hpp"
56 #include "utilities/copy.hpp"
57 #include "utilities/dtrace.hpp"
58 #include "utilities/macros.hpp"
59
60 /**
61 * Implementation of the jdk.internal.misc.Unsafe class
62 */
63
64
65 #define MAX_OBJECT_SIZE \
66 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
67 + ((julong)max_jint * sizeof(double)) )
68
69
70 #define UNSAFE_ENTRY(result_type, header) \
71 JVM_ENTRY(static result_type, header)
72
73 #define UNSAFE_LEAF(result_type, header) \
74 JVM_LEAF(static result_type, header)
75
76 #define UNSAFE_END JVM_END
77
78
79 static inline void* addr_from_java(jlong addr) {
80 // This assert fails in a variety of ways on 32-bit systems.
81 // It is impossible to predict whether native code that converts
82 // pointers to longs will sign-extend or zero-extend the addresses.
83 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
84 return (void*)(uintptr_t)addr;
85 }
86
87 static inline jlong addr_to_java(void* p) {
88 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
89 return (uintptr_t)p;
90 }
91
92
93 // Note: The VM's obj_field and related accessors use byte-scaled
94 // ("unscaled") offsets, just as the unsafe methods do.
95
96 // However, the method Unsafe.fieldOffset explicitly declines to
97 // guarantee this. The field offset values manipulated by the Java user
98 // through the Unsafe API are opaque cookies that just happen to be byte
99 // offsets. We represent this state of affairs by passing the cookies
100 // through conversion functions when going between the VM and the Unsafe API.
101 // The conversion functions just happen to be no-ops at present.
102
103 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
104 return field_offset;
105 }
106
107 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
108 return byte_offset;
109 }
110
111 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
112 #ifdef ASSERT
113 jlong byte_offset = field_offset_to_byte_offset(field_offset);
114
115 if (p != NULL) {
116 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
117 if (byte_offset == (jint)byte_offset) {
118 void* ptr_plus_disp = (address)p + byte_offset;
119 assert(p->field_addr_raw((jint)byte_offset) == ptr_plus_disp,
120 "raw [ptr+disp] must be consistent with oop::field_addr_raw");
121 }
122 jlong p_size = HeapWordSize * (jlong)(p->size());
123 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
124 }
125 #endif
126 }
127
128 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
129 assert_field_offset_sane(p, field_offset);
130 jlong byte_offset = field_offset_to_byte_offset(field_offset);
131
132 if (p != NULL) {
133 p = Access<>::resolve(p);
134 }
135
136 if (sizeof(char*) == sizeof(jint)) { // (this constant folds!)
137 return (address)p + (jint) byte_offset;
138 } else {
139 return (address)p + byte_offset;
140 }
141 }
142
143 // Externally callable versions:
144 // (Use these in compiler intrinsics which emulate unsafe primitives.)
145 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
146 return field_offset;
147 }
148 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
149 return byte_offset;
150 }
151
152 ///// Data read/writes on the Java heap and in native (off-heap) memory
153
154 /**
155 * Helper class for accessing memory.
156 *
157 * Normalizes values and wraps accesses in
158 * JavaThread::doing_unsafe_access() if needed.
159 */
160 template <typename T>
161 class MemoryAccess : StackObj {
162 JavaThread* _thread;
163 oop _obj;
164 ptrdiff_t _offset;
165
166 // Resolves and returns the address of the memory access.
167 // This raw memory access may fault, so we make sure it happens within the
168 // guarded scope by making the access volatile at least. Since the store
169 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
170 // can not be reordered by the compiler. Therefore, if the access triggers
171 // a fault, we will know that Thread::doing_unsafe_access() returns true.
172 volatile T* addr() {
173 void* addr = index_oop_from_field_offset_long(_obj, _offset);
174 return static_cast<volatile T*>(addr);
175 }
176
177 template <typename U>
178 U normalize_for_write(U x) {
179 return x;
180 }
181
182 jboolean normalize_for_write(jboolean x) {
183 return x & 1;
184 }
185
186 template <typename U>
187 U normalize_for_read(U x) {
188 return x;
189 }
190
191 jboolean normalize_for_read(jboolean x) {
192 return x != 0;
193 }
194
195 /**
196 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
197 */
198 class GuardUnsafeAccess {
199 JavaThread* _thread;
200
201 public:
202 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
203 // native/off-heap access which may raise SIGBUS if accessing
204 // memory mapped file data in a region of the file which has
205 // been truncated and is now invalid
206 _thread->set_doing_unsafe_access(true);
207 }
208
209 ~GuardUnsafeAccess() {
210 _thread->set_doing_unsafe_access(false);
211 }
212 };
213
214 public:
215 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
216 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
217 assert_field_offset_sane(_obj, offset);
218 }
219
220 T get() {
221 if (_obj == NULL) {
222 GuardUnsafeAccess guard(_thread);
223 T ret = RawAccess<>::load(addr());
224 return normalize_for_read(ret);
225 } else {
226 T ret = HeapAccess<>::load_at(_obj, _offset);
227 return normalize_for_read(ret);
228 }
229 }
230
231 void put(T x) {
232 if (_obj == NULL) {
233 GuardUnsafeAccess guard(_thread);
234 RawAccess<>::store(addr(), normalize_for_write(x));
235 } else {
236 HeapAccess<>::store_at(_obj, _offset, normalize_for_write(x));
237 }
238 }
239
240 void withfield(oop new_value, T x) {
241 guarantee(_obj != NULL, "off heap value access unimplemented");
242 ValueKlass* vk = ValueKlass::cast(new_value->klass());
243 vk->value_store(vk->data_for_oop(_obj), vk->data_for_oop(new_value), true, false);
244 HeapAccess<>::store_at(new_value, _offset, normalize_for_write(x));
245 }
246
247 T get_volatile() {
248 if (_obj == NULL) {
249 GuardUnsafeAccess guard(_thread);
250 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
251 return normalize_for_read(ret);
252 } else {
253 T ret = HeapAccess<MO_SEQ_CST>::load_at(_obj, _offset);
254 return normalize_for_read(ret);
255 }
256 }
257
258 void put_volatile(T x) {
259 if (_obj == NULL) {
260 GuardUnsafeAccess guard(_thread);
261 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
262 } else {
263 HeapAccess<MO_SEQ_CST>::store_at(_obj, _offset, normalize_for_write(x));
264 }
265 }
266 };
267
268 #ifdef ASSERT
269 /*
270 * Get the field descriptor of the field of the given object at the given offset.
271 */
272 static bool get_field_descriptor(oop p, jlong offset, fieldDescriptor* fd) {
273 bool found = false;
274 Klass* k = p->klass();
275 if (k->is_instance_klass()) {
276 InstanceKlass* ik = InstanceKlass::cast(k);
277 found = ik->find_field_from_offset((int)offset, false, fd);
278 if (!found && ik->is_mirror_instance_klass()) {
279 Klass* k2 = java_lang_Class::as_Klass(p);
280 if (k2->is_instance_klass()) {
281 ik = InstanceKlass::cast(k2);
282 found = ik->find_field_from_offset((int)offset, true, fd);
283 }
284 }
285 }
286 return found;
287 }
288 #endif // ASSERT
289
290 static void assert_and_log_unsafe_value_access(oop p, jlong offset, ValueKlass* vk) {
291 Klass* k = p->klass();
292 #ifdef ASSERT
293 if (k->is_instance_klass()) {
294 assert_field_offset_sane(p, offset);
295 fieldDescriptor fd;
296 bool found = get_field_descriptor(p, offset, &fd);
297 if (found) {
298 assert(found, "value field not found");
299 assert(fd.is_flattened(), "field not flat");
300 } else {
301 if (log_is_enabled(Trace, valuetypes)) {
302 log_trace(valuetypes)("not a field in %s at offset " SIZE_FORMAT_HEX,
303 p->klass()->external_name(), offset);
304 }
305 }
306 } else if (k->is_valueArray_klass()) {
307 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
308 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
309 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
310 assert(dest == ((address)p) + offset, "invalid offset");
311 } else {
312 ShouldNotReachHere();
313 }
314 #endif // ASSERT
315 if (log_is_enabled(Trace, valuetypes)) {
316 if (k->is_valueArray_klass()) {
317 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
318 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
319 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
320 log_trace(valuetypes)("%s array type %s index %d element size %d offset " SIZE_FORMAT_HEX " at " INTPTR_FORMAT,
321 p->klass()->external_name(), vak->external_name(),
322 index, vak->element_byte_size(), offset, p2i(dest));
323 } else {
324 log_trace(valuetypes)("%s field type %s at offset " SIZE_FORMAT_HEX,
325 p->klass()->external_name(), vk->external_name(), offset);
326 }
327 }
328 }
329
330 // These functions allow a null base pointer with an arbitrary address.
331 // But if the base pointer is non-null, the offset should make some sense.
332 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
333 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
334 oop p = JNIHandles::resolve(obj);
335 assert_field_offset_sane(p, offset);
336 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
337 return JNIHandles::make_local(env, v);
338 } UNSAFE_END
339
340 UNSAFE_ENTRY(void, Unsafe_PutObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
341 oop x = JNIHandles::resolve(x_h);
342 oop p = JNIHandles::resolve(obj);
343 assert_field_offset_sane(p, offset);
344 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
345 } UNSAFE_END
346
347 UNSAFE_ENTRY(jlong, Unsafe_ValueHeaderSize(JNIEnv *env, jobject unsafe, jclass c)) {
348 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
349 ValueKlass* vk = ValueKlass::cast(k);
350 return vk->first_field_offset();
351 } UNSAFE_END
352
353 UNSAFE_ENTRY(jboolean, Unsafe_IsFlattenedArray(JNIEnv *env, jobject unsafe, jclass c)) {
354 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
355 return k->is_valueArray_klass();
356 } UNSAFE_END
357
358 UNSAFE_ENTRY(jobject, Unsafe_GetValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc)) {
359 oop base = JNIHandles::resolve(obj);
360 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
361 ValueKlass* vk = ValueKlass::cast(k);
362 assert(!base->is_value() || base->mark()->is_larval_state(), "must be an object instance or a larval value");
363 assert_and_log_unsafe_value_access(base, offset, vk);
364 Handle base_h(THREAD, base);
365 oop v = vk->allocate_instance(CHECK_NULL); // allocate instance
366 vk->initialize(CHECK_NULL); // If field is a default value, value class might not be initialized yet
367 vk->value_store(((address)(oopDesc*)base_h()) + offset,
368 vk->data_for_oop(v),
369 true, true);
370 return JNIHandles::make_local(env, v);
371 } UNSAFE_END
372
373 UNSAFE_ENTRY(void, Unsafe_PutValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc, jobject value)) {
374 oop base = JNIHandles::resolve(obj);
375 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
376 ValueKlass* vk = ValueKlass::cast(k);
377 assert(!base->is_value() || base->mark()->is_larval_state(), "must be an object instance or a larval value");
378 assert_and_log_unsafe_value_access(base, offset, vk);
379 oop v = JNIHandles::resolve(value);
380 vk->value_store(vk->data_for_oop(v),
381 ((address)(oopDesc*)base) + offset, true, true);
382 } UNSAFE_END
383
384 UNSAFE_ENTRY(jobject, Unsafe_StartPrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) {
385 oop v = JNIHandles::resolve_non_null(value);
386 assert(v->is_value(), "must be a value instance");
387 Handle vh(THREAD, v);
388 ValueKlass* vk = ValueKlass::cast(v->klass());
389 instanceOop new_value = vk->allocate_instance(CHECK_NULL);
390 vk->value_store(vk->data_for_oop(vh()), vk->data_for_oop(new_value), true, false);
391 markOop mark = new_value->mark();
392 new_value->set_mark(mark->enter_larval_state());
393 return JNIHandles::make_local(env, new_value);
394 } UNSAFE_END
395
396 UNSAFE_ENTRY(jobject, Unsafe_FinishPrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) {
397 oop v = JNIHandles::resolve(value);
398 assert(v->mark()->is_larval_state(), "must be a larval value");
399 markOop mark = v->mark();
400 v->set_mark(mark->exit_larval_state());
401 return JNIHandles::make_local(env, v);
402 } UNSAFE_END
403
404 UNSAFE_ENTRY(jobject, Unsafe_WithValue(JNIEnv *env, jobject unsafe, jclass vc, jobject obj, jlong vc_offset, jlong offset, jclass xc, jobject x)) {
405 // base can be of any type T which is a value-within-a-value-within...-a-value
406 // base+vc_offset is the address of a buffered value of VC
407 // new_value is an instance of VC
408 // new_value+offset is a buffered value of XC
409 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
410 ValueKlass* vk = ValueKlass::cast(k);
411 oop base = JNIHandles::resolve(obj);
412 Handle base_h(THREAD, base);
413
414 Klass* field_k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(xc));
415 ValueKlass* field_vk = ValueKlass::cast(field_k);
416 oop x_oop = JNIHandles::resolve(x);
417 assert(field_vk == x_oop->klass(), "Must match");
418
419 if (log_is_enabled(Trace, valuetypes)) {
420 LogTarget(Trace, valuetypes) lt;
421 if (lt.is_enabled()) {
422 ResourceMark rm(THREAD);
423 LogStream ls(lt);
424 outputStream* st = &ls;
425 st->print_cr("withValue: object %s at " SIZE_FORMAT_HEX " container %s field type %s at offset " SIZE_FORMAT_HEX,
426 base_h->klass()->external_name(), vc_offset,
427 vk->external_name(), field_vk->external_name(), offset);
428 base_h->print_on(st);
429 }
430 }
431
432 // Create new value of VC by copying the value at vc_offset
433 instanceOop new_value = vk->allocate_instance(CHECK_NULL);
434 Handle new_value_h(THREAD, new_value);
435 vk->value_store(((address)(oopDesc*)base_h()) + vc_offset, vk->data_for_oop(new_value), true, false);
436 // patch xc_offset at new_value with x
437 field_vk->value_store(field_vk->data_for_oop(x_oop),
438 ((address)(oopDesc*)new_value_h()) + offset, true, false);
439
440 if (log_is_enabled(Trace, valuetypes)) {
441 LogTarget(Trace, valuetypes) lt;
442 if (lt.is_enabled()) {
443 ResourceMark rm(THREAD);
444 LogStream ls(lt);
445 outputStream* st = &ls;
446 st->print_cr("------ after patching ---- ");
447 new_value_h->print_on(st);
448 }
449 }
450 return JNIHandles::make_local(env, new_value_h());
451 } UNSAFE_END
452
453 UNSAFE_ENTRY(jobject, Unsafe_WithReference(JNIEnv *env, jobject unsafe, jclass vc, jobject obj, jlong offset, jobject x)) {
454 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
455 ValueKlass* vk = ValueKlass::cast(k);
456 oop base = JNIHandles::resolve(obj);
457 Handle base_h(THREAD, base);
458 assert_field_offset_sane(base, offset);
459
460 instanceOop new_value = vk->allocate_instance(CHECK_NULL);
461 vk->value_store(((address)(oopDesc*)base_h()) + vk->first_field_offset(), vk->data_for_oop(new_value), true, false);
462 oop x_oop = JNIHandles::resolve(x);
463 new_value->obj_field_put(offset, x_oop);
464 return JNIHandles::make_local(env, new_value);
465 } UNSAFE_END
466
467 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
468 oop p = JNIHandles::resolve(obj);
469 assert_field_offset_sane(p, offset);
470 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
471 return JNIHandles::make_local(env, v);
472 } UNSAFE_END
473
474 UNSAFE_ENTRY(void, Unsafe_PutObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
475 oop x = JNIHandles::resolve(x_h);
476 oop p = JNIHandles::resolve(obj);
477 assert_field_offset_sane(p, offset);
478 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
479 } UNSAFE_END
480
481 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
482 oop v = *(oop*) (address) addr;
483 return JNIHandles::make_local(env, v);
484 } UNSAFE_END
485
486 UNSAFE_LEAF(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe)) {
487 #ifdef VM_LITTLE_ENDIAN
488 return false;
489 #else
490 return true;
491 #endif
492 } UNSAFE_END
493
494 UNSAFE_LEAF(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe)) {
495 return UseUnalignedAccesses;
496 } UNSAFE_END
497
498 #define DEFINE_GETSETOOP(java_type, Type) \
499 \
500 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
501 return MemoryAccess<java_type>(thread, obj, offset).get(); \
502 } UNSAFE_END \
503 \
504 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
505 MemoryAccess<java_type>(thread, obj, offset).put(x); \
506 } UNSAFE_END \
507 \
508 UNSAFE_ENTRY(jobject, Unsafe_With##Type(JNIEnv *env, jobject unsafe, jclass vc, jobject obj, jlong offset, java_type x)) { \
509 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)); \
510 ValueKlass* vk = ValueKlass::cast(k); \
511 instanceOop new_value = vk->allocate_instance(CHECK_NULL); \
512 MemoryAccess<java_type>(thread, obj, offset).withfield(new_value, x); \
513 return JNIHandles::make_local(env, new_value); \
514 } UNSAFE_END \
515 \
516 // END DEFINE_GETSETOOP.
517
518 DEFINE_GETSETOOP(jboolean, Boolean)
519 DEFINE_GETSETOOP(jbyte, Byte)
520 DEFINE_GETSETOOP(jshort, Short);
521 DEFINE_GETSETOOP(jchar, Char);
522 DEFINE_GETSETOOP(jint, Int);
523 DEFINE_GETSETOOP(jlong, Long);
524 DEFINE_GETSETOOP(jfloat, Float);
525 DEFINE_GETSETOOP(jdouble, Double);
526
527 #undef DEFINE_GETSETOOP
528
529 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
530 \
531 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
532 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
533 } UNSAFE_END \
534 \
535 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
536 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
537 } UNSAFE_END \
538 \
539 // END DEFINE_GETSETOOP_VOLATILE.
540
541 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
542 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
543 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
544 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
545 DEFINE_GETSETOOP_VOLATILE(jint, Int);
546 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
547 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
548 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
549
550 #undef DEFINE_GETSETOOP_VOLATILE
551
552 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
553 OrderAccess::acquire();
554 } UNSAFE_END
555
556 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
557 OrderAccess::release();
558 } UNSAFE_END
559
560 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
561 OrderAccess::fence();
562 } UNSAFE_END
563
564 ////// Allocation requests
565
566 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
567 ThreadToNativeFromVM ttnfv(thread);
568 return env->AllocObject(cls);
569 } UNSAFE_END
570
571 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
572 size_t sz = (size_t)size;
573
574 sz = align_up(sz, HeapWordSize);
575 void* x = os::malloc(sz, mtOther);
576
577 return addr_to_java(x);
578 } UNSAFE_END
579
580 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
581 void* p = addr_from_java(addr);
582 size_t sz = (size_t)size;
583 sz = align_up(sz, HeapWordSize);
584
585 void* x = os::realloc(p, sz, mtOther);
586
587 return addr_to_java(x);
588 } UNSAFE_END
589
590 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
591 void* p = addr_from_java(addr);
592
593 os::free(p);
594 } UNSAFE_END
595
596 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
597 size_t sz = (size_t)size;
598
599 oop base = JNIHandles::resolve(obj);
600 void* p = index_oop_from_field_offset_long(base, offset);
601
602 Copy::fill_to_memory_atomic(p, sz, value);
603 } UNSAFE_END
604
605 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
606 size_t sz = (size_t)size;
607
608 oop srcp = JNIHandles::resolve(srcObj);
609 oop dstp = JNIHandles::resolve(dstObj);
610
611 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
612 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
613
614 Copy::conjoint_memory_atomic(src, dst, sz);
615 } UNSAFE_END
616
617 // This function is a leaf since if the source and destination are both in native memory
618 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
619 // If either source or destination (or both) are on the heap, the function will enter VM using
620 // JVM_ENTRY_FROM_LEAF
621 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
622 size_t sz = (size_t)size;
623 size_t esz = (size_t)elemSize;
624
625 if (srcObj == NULL && dstObj == NULL) {
626 // Both src & dst are in native memory
627 address src = (address)srcOffset;
628 address dst = (address)dstOffset;
629
630 Copy::conjoint_swap(src, dst, sz, esz);
631 } else {
632 // At least one of src/dst are on heap, transition to VM to access raw pointers
633
634 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
635 oop srcp = JNIHandles::resolve(srcObj);
636 oop dstp = JNIHandles::resolve(dstObj);
637
638 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
639 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
640
641 Copy::conjoint_swap(src, dst, sz, esz);
642 } JVM_END
643 }
644 } UNSAFE_END
645
646 ////// Random queries
647
648 UNSAFE_LEAF(jint, Unsafe_AddressSize0(JNIEnv *env, jobject unsafe)) {
649 return sizeof(void*);
650 } UNSAFE_END
651
652 UNSAFE_LEAF(jint, Unsafe_PageSize()) {
653 return os::vm_page_size();
654 } UNSAFE_END
655
656 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
657 assert(clazz != NULL, "clazz must not be NULL");
658 assert(name != NULL, "name must not be NULL");
659
660 ResourceMark rm(THREAD);
661 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
662
663 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
664
665 jint offset = -1;
666 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
667 Symbol *name = fs.name();
668 if (name->equals(utf_name)) {
669 offset = fs.offset();
670 break;
671 }
672 }
673 if (offset < 0) {
674 THROW_0(vmSymbols::java_lang_InternalError());
675 }
676 return field_offset_from_byte_offset(offset);
677 }
678
679 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
680 assert(field != NULL, "field must not be NULL");
681
682 oop reflected = JNIHandles::resolve_non_null(field);
683 oop mirror = java_lang_reflect_Field::clazz(reflected);
684 Klass* k = java_lang_Class::as_Klass(mirror);
685 int slot = java_lang_reflect_Field::slot(reflected);
686 int modifiers = java_lang_reflect_Field::modifiers(reflected);
687
688 if (must_be_static >= 0) {
689 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
690 if (must_be_static != really_is_static) {
691 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
692 }
693 }
694
695 int offset = InstanceKlass::cast(k)->field_offset(slot);
696 return field_offset_from_byte_offset(offset);
697 }
698
699 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
700 return find_field_offset(field, 0, THREAD);
701 } UNSAFE_END
702
703 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
704 return find_field_offset(c, name, THREAD);
705 } UNSAFE_END
706
707 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
708 return find_field_offset(field, 1, THREAD);
709 } UNSAFE_END
710
711 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
712 assert(field != NULL, "field must not be NULL");
713
714 // Note: In this VM implementation, a field address is always a short
715 // offset from the base of a a klass metaobject. Thus, the full dynamic
716 // range of the return type is never used. However, some implementations
717 // might put the static field inside an array shared by many classes,
718 // or even at a fixed address, in which case the address could be quite
719 // large. In that last case, this function would return NULL, since
720 // the address would operate alone, without any base pointer.
721
722 oop reflected = JNIHandles::resolve_non_null(field);
723 oop mirror = java_lang_reflect_Field::clazz(reflected);
724 int modifiers = java_lang_reflect_Field::modifiers(reflected);
725
726 if ((modifiers & JVM_ACC_STATIC) == 0) {
727 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
728 }
729
730 return JNIHandles::make_local(env, mirror);
731 } UNSAFE_END
732
733 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
734 assert(clazz != NULL, "clazz must not be NULL");
735
736 oop mirror = JNIHandles::resolve_non_null(clazz);
737
738 Klass* klass = java_lang_Class::as_Klass(mirror);
739 if (klass != NULL && klass->should_be_initialized()) {
740 InstanceKlass* k = InstanceKlass::cast(klass);
741 k->initialize(CHECK);
742 }
743 }
744 UNSAFE_END
745
746 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
747 assert(clazz != NULL, "clazz must not be NULL");
748
749 oop mirror = JNIHandles::resolve_non_null(clazz);
750 Klass* klass = java_lang_Class::as_Klass(mirror);
751
752 if (klass != NULL && klass->should_be_initialized()) {
753 return true;
754 }
755
756 return false;
757 }
758 UNSAFE_END
759
760 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
761 assert(clazz != NULL, "clazz must not be NULL");
762
763 oop mirror = JNIHandles::resolve_non_null(clazz);
764 Klass* k = java_lang_Class::as_Klass(mirror);
765
766 if (k == NULL || !k->is_array_klass()) {
767 THROW(vmSymbols::java_lang_InvalidClassException());
768 } else if (k->is_objArray_klass()) {
769 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
770 scale = heapOopSize;
771 } else if (k->is_typeArray_klass()) {
772 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
773 base = tak->array_header_in_bytes();
774 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
775 scale = (1 << tak->log2_element_size());
776 } else if (k->is_valueArray_klass()) {
777 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
778 ValueKlass* vklass = vak->element_klass();
779 base = vak->array_header_in_bytes();
780 scale = vak->element_byte_size();
781 } else {
782 ShouldNotReachHere();
783 }
784 }
785
786 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
787 int base = 0, scale = 0;
788 getBaseAndScale(base, scale, clazz, CHECK_0);
789
790 return field_offset_from_byte_offset(base);
791 } UNSAFE_END
792
793
794 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
795 int base = 0, scale = 0;
796 getBaseAndScale(base, scale, clazz, CHECK_0);
797
798 // This VM packs both fields and array elements down to the byte.
799 // But watch out: If this changes, so that array references for
800 // a given primitive type (say, T_BOOLEAN) use different memory units
801 // than fields, this method MUST return zero for such arrays.
802 // For example, the VM used to store sub-word sized fields in full
803 // words in the object layout, so that accessors like getByte(Object,int)
804 // did not really do what one might expect for arrays. Therefore,
805 // this function used to report a zero scale factor, so that the user
806 // would know not to attempt to access sub-word array elements.
807 // // Code for unpacked fields:
808 // if (scale < wordSize) return 0;
809
810 // The following allows for a pretty general fieldOffset cookie scheme,
811 // but requires it to be linear in byte offset.
812 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
813 } UNSAFE_END
814
815
816 static inline void throw_new(JNIEnv *env, const char *ename) {
817 jclass cls = env->FindClass(ename);
818 if (env->ExceptionCheck()) {
819 env->ExceptionClear();
820 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
821 return;
822 }
823
824 env->ThrowNew(cls, NULL);
825 }
826
827 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
828 // Code lifted from JDK 1.3 ClassLoader.c
829
830 jbyte *body;
831 char *utfName = NULL;
832 jclass result = 0;
833 char buf[128];
834
835 assert(data != NULL, "Class bytes must not be NULL");
836 assert(length >= 0, "length must not be negative: %d", length);
837
838 if (UsePerfData) {
839 ClassLoader::unsafe_defineClassCallCounter()->inc();
840 }
841
842 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
843 if (body == NULL) {
844 throw_new(env, "java/lang/OutOfMemoryError");
845 return 0;
846 }
847
848 env->GetByteArrayRegion(data, offset, length, body);
849 if (env->ExceptionOccurred()) {
850 goto free_body;
851 }
852
853 if (name != NULL) {
854 uint len = env->GetStringUTFLength(name);
855 int unicode_len = env->GetStringLength(name);
856
857 if (len >= sizeof(buf)) {
858 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
859 if (utfName == NULL) {
860 throw_new(env, "java/lang/OutOfMemoryError");
861 goto free_body;
862 }
863 } else {
864 utfName = buf;
865 }
866
867 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
868
869 for (uint i = 0; i < len; i++) {
870 if (utfName[i] == '.') utfName[i] = '/';
871 }
872 }
873
874 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
875
876 if (utfName && utfName != buf) {
877 FREE_C_HEAP_ARRAY(char, utfName);
878 }
879
880 free_body:
881 FREE_C_HEAP_ARRAY(jbyte, body);
882 return result;
883 }
884
885
886 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
887 ThreadToNativeFromVM ttnfv(thread);
888
889 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
890 } UNSAFE_END
891
892
893 // define a class but do not make it known to the class loader or system dictionary
894 // - host_class: supplies context for linkage, access control, protection domain, and class loader
895 // if host_class is itself anonymous then it is replaced with its host class.
896 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
897 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
898
899 // When you load an anonymous class U, it works as if you changed its name just before loading,
900 // to a name that you will never use again. Since the name is lost, no other class can directly
901 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
902 // through java.lang.Class methods like Class.newInstance.
903
904 // The package of an anonymous class must either match its host's class's package or be in the
905 // unnamed package. If it is in the unnamed package then it will be put in its host class's
906 // package.
907 //
908
909 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
910 // An anonymous class also has special privileges to access any member of its host class.
911 // This is the main reason why this loading operation is unsafe. The purpose of this is to
912 // allow language implementations to simulate "open classes"; a host class in effect gets
913 // new code when an anonymous class is loaded alongside it. A less convenient but more
914 // standard way to do this is with reflection, which can also be set to ignore access
915 // restrictions.
916
917 // Access into an anonymous class is possible only through reflection. Therefore, there
918 // are no special access rules for calling into an anonymous class. The relaxed access
919 // rule for the host class is applied in the opposite direction: A host class reflectively
920 // access one of its anonymous classes.
921
922 // If you load the same bytecodes twice, you get two different classes. You can reload
923 // the same bytecodes with or without varying CP patches.
924
925 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
926 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
927 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
928
929 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
930 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
931 // It is not possible for a named class, or an older anonymous class, to refer by
932 // name (via its CP) to a newer anonymous class.
933
934 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
935 // or type descriptors used in the loaded anonymous class.
936
937 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
938 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
939 // be changed to println(greeting), where greeting is an arbitrary object created before
940 // the anonymous class is loaded. This is useful in dynamic languages, in which
941 // various kinds of metaobjects must be introduced as constants into bytecode.
942 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
943 // not just a literal string. For such ldc instructions, the verifier uses the
944 // type Object instead of String, if the loaded constant is not in fact a String.
945
946 static InstanceKlass*
947 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
948 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
949 u1** temp_alloc,
950 TRAPS) {
951 assert(host_class != NULL, "host_class must not be NULL");
952 assert(data != NULL, "data must not be NULL");
953
954 if (UsePerfData) {
955 ClassLoader::unsafe_defineClassCallCounter()->inc();
956 }
957
958 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
959 assert(length >= 0, "class_bytes_length must not be negative: %d", length);
960
961 int class_bytes_length = (int) length;
962
963 u1* class_bytes = NEW_C_HEAP_ARRAY(u1, length, mtInternal);
964 if (class_bytes == NULL) {
965 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
966 }
967
968 // caller responsible to free it:
969 *temp_alloc = class_bytes;
970
971 ArrayAccess<>::arraycopy_to_native(arrayOop(JNIHandles::resolve_non_null(data)), typeArrayOopDesc::element_offset<jbyte>(0),
972 reinterpret_cast<jbyte*>(class_bytes), length);
973
974 objArrayHandle cp_patches_h;
975 if (cp_patches_jh != NULL) {
976 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
977 assert(p->is_objArray(), "cp_patches must be an object[]");
978 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
979 }
980
981 const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
982
983 // Make sure it's the real host class, not another anonymous class.
984 while (host_klass != NULL && host_klass->is_instance_klass() &&
985 InstanceKlass::cast(host_klass)->is_unsafe_anonymous()) {
986 host_klass = InstanceKlass::cast(host_klass)->unsafe_anonymous_host();
987 }
988
989 // Primitive types have NULL Klass* fields in their java.lang.Class instances.
990 if (host_klass == NULL) {
991 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
992 }
993
994 assert(host_klass->is_instance_klass(), "Host class must be an instance class");
995
996 const char* host_source = host_klass->external_name();
997 Handle host_loader(THREAD, host_klass->class_loader());
998 Handle host_domain(THREAD, host_klass->protection_domain());
999
1000 GrowableArray<Handle>* cp_patches = NULL;
1001
1002 if (cp_patches_h.not_null()) {
1003 int alen = cp_patches_h->length();
1004
1005 for (int i = alen-1; i >= 0; i--) {
1006 oop p = cp_patches_h->obj_at(i);
1007 if (p != NULL) {
1008 Handle patch(THREAD, p);
1009
1010 if (cp_patches == NULL) {
1011 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
1012 }
1013
1014 cp_patches->at_put(i, patch);
1015 }
1016 }
1017 }
1018
1019 ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
1020
1021 Symbol* no_class_name = NULL;
1022 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
1023 host_loader,
1024 host_domain,
1025 &st,
1026 InstanceKlass::cast(host_klass),
1027 cp_patches,
1028 CHECK_NULL);
1029 if (anonk == NULL) {
1030 return NULL;
1031 }
1032
1033 return InstanceKlass::cast(anonk);
1034 }
1035
1036 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
1037 ResourceMark rm(THREAD);
1038
1039 jobject res_jh = NULL;
1040 u1* temp_alloc = NULL;
1041
1042 InstanceKlass* anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
1043 if (anon_klass != NULL) {
1044 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
1045 }
1046
1047 // try/finally clause:
1048 if (temp_alloc != NULL) {
1049 FREE_C_HEAP_ARRAY(u1, temp_alloc);
1050 }
1051
1052 // The anonymous class loader data has been artificially been kept alive to
1053 // this point. The mirror and any instances of this class have to keep
1054 // it alive afterwards.
1055 if (anon_klass != NULL) {
1056 anon_klass->class_loader_data()->dec_keep_alive();
1057 }
1058
1059 // let caller initialize it as needed...
1060
1061 return (jclass) res_jh;
1062 } UNSAFE_END
1063
1064
1065
1066 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
1067 ThreadToNativeFromVM ttnfv(thread);
1068 env->Throw(thr);
1069 } UNSAFE_END
1070
1071 // JSR166 ------------------------------------------------------------------
1072
1073 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1074 oop x = JNIHandles::resolve(x_h);
1075 oop e = JNIHandles::resolve(e_h);
1076 oop p = JNIHandles::resolve(obj);
1077 assert_field_offset_sane(p, offset);
1078 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1079 return JNIHandles::make_local(env, res);
1080 } UNSAFE_END
1081
1082 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1083 oop p = JNIHandles::resolve(obj);
1084 if (p == NULL) {
1085 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1086 return RawAccess<>::atomic_cmpxchg(x, addr, e);
1087 } else {
1088 assert_field_offset_sane(p, offset);
1089 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1090 }
1091 } UNSAFE_END
1092
1093 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1094 oop p = JNIHandles::resolve(obj);
1095 if (p == NULL) {
1096 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1097 return RawAccess<>::atomic_cmpxchg(x, addr, e);
1098 } else {
1099 assert_field_offset_sane(p, offset);
1100 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1101 }
1102 } UNSAFE_END
1103
1104 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1105 oop x = JNIHandles::resolve(x_h);
1106 oop e = JNIHandles::resolve(e_h);
1107 oop p = JNIHandles::resolve(obj);
1108 assert_field_offset_sane(p, offset);
1109 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1110 return oopDesc::equals(ret, e);
1111 } UNSAFE_END
1112
1113 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1114 oop p = JNIHandles::resolve(obj);
1115 if (p == NULL) {
1116 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1117 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
1118 } else {
1119 assert_field_offset_sane(p, offset);
1120 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
1121 }
1122 } UNSAFE_END
1123
1124 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1125 oop p = JNIHandles::resolve(obj);
1126 if (p == NULL) {
1127 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1128 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
1129 } else {
1130 assert_field_offset_sane(p, offset);
1131 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
1132 }
1133 } UNSAFE_END
1134
1135 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout) {
1136 assert(event != NULL, "invariant");
1137 assert(event->should_commit(), "invariant");
1138 event->set_parkedClass((obj != NULL) ? obj->klass() : NULL);
1139 event->set_timeout(timeout);
1140 event->set_address((obj != NULL) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1141 event->commit();
1142 }
1143
1144 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1145 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1146 EventThreadPark event;
1147
1148 JavaThreadParkedState jtps(thread, time != 0);
1149 thread->parker()->park(isAbsolute != 0, time);
1150 if (event.should_commit()) {
1151 post_thread_park_event(&event, thread->current_park_blocker(), time);
1152 }
1153 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1154 } UNSAFE_END
1155
1156 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1157 Parker* p = NULL;
1158
1159 if (jthread != NULL) {
1160 ThreadsListHandle tlh;
1161 JavaThread* thr = NULL;
1162 oop java_thread = NULL;
1163 (void) tlh.cv_internal_thread_to_JavaThread(jthread, &thr, &java_thread);
1164 if (java_thread != NULL) {
1165 // This is a valid oop.
1166 jlong lp = java_lang_Thread::park_event(java_thread);
1167 if (lp != 0) {
1168 // This cast is OK even though the jlong might have been read
1169 // non-atomically on 32bit systems, since there, one word will
1170 // always be zero anyway and the value set is always the same
1171 p = (Parker*)addr_from_java(lp);
1172 } else {
1173 // Not cached in the java.lang.Thread oop yet (could be an
1174 // older version of library).
1175 if (thr != NULL) {
1176 // The JavaThread is alive.
1177 p = thr->parker();
1178 if (p != NULL) {
1179 // Cache the Parker in the java.lang.Thread oop for next time.
1180 java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1181 }
1182 }
1183 }
1184 }
1185 } // ThreadsListHandle is destroyed here.
1186
1187 if (p != NULL) {
1188 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1189 p->unpark();
1190 }
1191 } UNSAFE_END
1192
1193 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1194 const int max_nelem = 3;
1195 double la[max_nelem];
1196 jint ret;
1197
1198 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1199 assert(a->is_typeArray(), "must be type array");
1200
1201 ret = os::loadavg(la, nelem);
1202 if (ret == -1) {
1203 return -1;
1204 }
1205
1206 // if successful, ret is the number of samples actually retrieved.
1207 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1208 switch(ret) {
1209 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1210 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1211 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1212 }
1213
1214 return ret;
1215 } UNSAFE_END
1216
1217
1218 /// JVM_RegisterUnsafeMethods
1219
1220 #define ADR "J"
1221
1222 #define LANG "Ljava/lang/"
1223
1224 #define OBJ LANG "Object;"
1225 #define CLS LANG "Class;"
1226 #define FLD LANG "reflect/Field;"
1227 #define THR LANG "Throwable;"
1228
1229 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1230 #define DAC_Args CLS "[B[" OBJ
1231
1232 #define CC (char*) /*cast a literal from (const char*)*/
1233 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1234
1235 #define DECLARE_GETPUTOOP(Type, Desc) \
1236 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1237 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1238 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1239 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}, \
1240 {CC "with" #Type, CC "(" CLS OBJ "J" #Desc ")" OBJ, FN_PTR(Unsafe_With##Type)}
1241
1242
1243 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1244 {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)},
1245 {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObject)},
1246 {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)},
1247 {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObjectVolatile)},
1248
1249 {CC "isFlattenedArray", CC "(" CLS ")Z", FN_PTR(Unsafe_IsFlattenedArray)},
1250 {CC "valueHeaderSize", CC "(" CLS ")J", FN_PTR(Unsafe_ValueHeaderSize)},
1251 {CC "getValue", CC "(" OBJ "J" CLS ")" OBJ, FN_PTR(Unsafe_GetValue)},
1252 {CC "putValue", CC "(" OBJ "J" CLS OBJ ")V", FN_PTR(Unsafe_PutValue)},
1253 {CC "withValue", CC "(" CLS OBJ "JJ" CLS OBJ ")" OBJ, FN_PTR(Unsafe_WithValue)},
1254 {CC "withReference", CC "(" CLS OBJ "J" OBJ ")" OBJ, FN_PTR(Unsafe_WithReference)},
1255 {CC "startPrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_StartPrivateBuffer)},
1256 {CC "finishPrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_FinishPrivateBuffer)},
1257
1258 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1259
1260 DECLARE_GETPUTOOP(Boolean, Z),
1261 DECLARE_GETPUTOOP(Byte, B),
1262 DECLARE_GETPUTOOP(Short, S),
1263 DECLARE_GETPUTOOP(Char, C),
1264 DECLARE_GETPUTOOP(Int, I),
1265 DECLARE_GETPUTOOP(Long, J),
1266 DECLARE_GETPUTOOP(Float, F),
1267 DECLARE_GETPUTOOP(Double, D),
1268
1269 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1270 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1271 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1272
1273 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1274 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1275 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1276 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1277 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1278 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1279 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1280 {CC "addressSize0", CC "()I", FN_PTR(Unsafe_AddressSize0)},
1281 {CC "pageSize", CC "()I", FN_PTR(Unsafe_PageSize)},
1282
1283 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1284 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1285 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1286 {CC "compareAndSetObject",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetObject)},
1287 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1288 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1289 {CC "compareAndExchangeObject", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeObject)},
1290 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1291 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1292
1293 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1294 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1295
1296 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1297
1298 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1299 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1300 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1301
1302 {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1303
1304 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1305
1306 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1307 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1308 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1309
1310 {CC "isBigEndian0", CC "()Z", FN_PTR(Unsafe_isBigEndian0)},
1311 {CC "unalignedAccess0", CC "()Z", FN_PTR(Unsafe_unalignedAccess0)}
1312 };
1313
1314 #undef CC
1315 #undef FN_PTR
1316
1317 #undef ADR
1318 #undef LANG
1319 #undef OBJ
1320 #undef CLS
1321 #undef FLD
1322 #undef THR
1323 #undef DC_Args
1324 #undef DAC_Args
1325
1326 #undef DECLARE_GETPUTOOP
1327
1328
1329 // This function is exported, used by NativeLookup.
1330 // The Unsafe_xxx functions above are called only from the interpreter.
1331 // The optimizer looks at names and signatures to recognize
1332 // individual functions.
1333
1334 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1335 ThreadToNativeFromVM ttnfv(thread);
1336
1337 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1338 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1339 } JVM_END