unsafe.cpp revision 9056:dc9930a04ab0
1/* 2 * Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#include "precompiled.hpp" 26#include "classfile/vmSymbols.hpp" 27#include "memory/allocation.inline.hpp" 28#include "oops/objArrayOop.inline.hpp" 29#include "oops/oop.inline.hpp" 30#include "prims/jni.h" 31#include "prims/jvm.h" 32#include "runtime/atomic.inline.hpp" 33#include "runtime/globals.hpp" 34#include "runtime/interfaceSupport.hpp" 35#include "runtime/orderAccess.inline.hpp" 36#include "runtime/reflection.hpp" 37#include "runtime/vm_version.hpp" 38#include "services/threadService.hpp" 39#include "trace/tracing.hpp" 40#include "utilities/copy.hpp" 41#include "utilities/dtrace.hpp" 42#include "utilities/macros.hpp" 43#if INCLUDE_ALL_GCS 44#include "gc/g1/g1SATBCardTableModRefBS.hpp" 45#endif // INCLUDE_ALL_GCS 46 47PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 48 49/* 50 * Implementation of class sun.misc.Unsafe 51 */ 52 53 54#define MAX_OBJECT_SIZE \ 55 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \ 56 + ((julong)max_jint * sizeof(double)) ) 57 58 59#define UNSAFE_ENTRY(result_type, header) \ 60 JVM_ENTRY(result_type, header) 61 62// Can't use UNSAFE_LEAF because it has the signature of a straight 63// call into the runtime (just like JVM_LEAF, funny that) but it's 64// called like a Java Native and thus the wrapper built for it passes 65// arguments like a JNI call. It expects those arguments to be popped 66// from the stack on Intel like all good JNI args are, and adjusts the 67// stack according. Since the JVM_LEAF call expects no extra 68// arguments the stack isn't popped in the C code, is pushed by the 69// wrapper and we get sick. 70//#define UNSAFE_LEAF(result_type, header) \ 71// JVM_LEAF(result_type, header) 72 73#define UNSAFE_END JVM_END 74 75#define UnsafeWrapper(arg) /*nothing, for the present*/ 76 77 78inline void* addr_from_java(jlong addr) { 79 // This assert fails in a variety of ways on 32-bit systems. 80 // It is impossible to predict whether native code that converts 81 // pointers to longs will sign-extend or zero-extend the addresses. 82 //assert(addr == (uintptr_t)addr, "must not be odd high bits"); 83 return (void*)(uintptr_t)addr; 84} 85 86inline jlong addr_to_java(void* p) { 87 assert(p == (void*)(uintptr_t)p, "must not be odd high bits"); 88 return (uintptr_t)p; 89} 90 91 92// Note: The VM's obj_field and related accessors use byte-scaled 93// ("unscaled") offsets, just as the unsafe methods do. 94 95// However, the method Unsafe.fieldOffset explicitly declines to 96// guarantee this. The field offset values manipulated by the Java user 97// through the Unsafe API are opaque cookies that just happen to be byte 98// offsets. We represent this state of affairs by passing the cookies 99// through conversion functions when going between the VM and the Unsafe API. 100// The conversion functions just happen to be no-ops at present. 101 102inline jlong field_offset_to_byte_offset(jlong field_offset) { 103 return field_offset; 104} 105 106inline jlong field_offset_from_byte_offset(jlong byte_offset) { 107 return byte_offset; 108} 109 110inline jint invocation_key_from_method_slot(jint slot) { 111 return slot; 112} 113 114inline jint invocation_key_to_method_slot(jint key) { 115 return key; 116} 117 118inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) { 119 jlong byte_offset = field_offset_to_byte_offset(field_offset); 120#ifdef ASSERT 121 if (p != NULL) { 122 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset"); 123 if (byte_offset == (jint)byte_offset) { 124 void* ptr_plus_disp = (address)p + byte_offset; 125 assert((void*)p->obj_field_addr<oop>((jint)byte_offset) == ptr_plus_disp, 126 "raw [ptr+disp] must be consistent with oop::field_base"); 127 } 128 jlong p_size = HeapWordSize * (jlong)(p->size()); 129 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, byte_offset, p_size); 130 } 131#endif 132 if (sizeof(char*) == sizeof(jint)) // (this constant folds!) 133 return (address)p + (jint) byte_offset; 134 else 135 return (address)p + byte_offset; 136} 137 138// Externally callable versions: 139// (Use these in compiler intrinsics which emulate unsafe primitives.) 140jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) { 141 return field_offset; 142} 143jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) { 144 return byte_offset; 145} 146jint Unsafe_invocation_key_from_method_slot(jint slot) { 147 return invocation_key_from_method_slot(slot); 148} 149jint Unsafe_invocation_key_to_method_slot(jint key) { 150 return invocation_key_to_method_slot(key); 151} 152 153 154///// Data in the Java heap. 155 156#define GET_FIELD(obj, offset, type_name, v) \ 157 oop p = JNIHandles::resolve(obj); \ 158 type_name v = *(type_name*)index_oop_from_field_offset_long(p, offset) 159 160#define SET_FIELD(obj, offset, type_name, x) \ 161 oop p = JNIHandles::resolve(obj); \ 162 *(type_name*)index_oop_from_field_offset_long(p, offset) = x 163 164#define GET_FIELD_VOLATILE(obj, offset, type_name, v) \ 165 oop p = JNIHandles::resolve(obj); \ 166 if (support_IRIW_for_not_multiple_copy_atomic_cpu) { \ 167 OrderAccess::fence(); \ 168 } \ 169 volatile type_name v = OrderAccess::load_acquire((volatile type_name*)index_oop_from_field_offset_long(p, offset)); 170 171#define SET_FIELD_VOLATILE(obj, offset, type_name, x) \ 172 oop p = JNIHandles::resolve(obj); \ 173 OrderAccess::release_store_fence((volatile type_name*)index_oop_from_field_offset_long(p, offset), x); 174 175 176// Get/SetObject must be special-cased, since it works with handles. 177 178// These functions allow a null base pointer with an arbitrary address. 179// But if the base pointer is non-null, the offset should make some sense. 180// That is, it should be in the range [0, MAX_OBJECT_SIZE]. 181UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) 182 UnsafeWrapper("Unsafe_GetObject"); 183 oop p = JNIHandles::resolve(obj); 184 oop v; 185 if (UseCompressedOops) { 186 narrowOop n = *(narrowOop*)index_oop_from_field_offset_long(p, offset); 187 v = oopDesc::decode_heap_oop(n); 188 } else { 189 v = *(oop*)index_oop_from_field_offset_long(p, offset); 190 } 191 jobject ret = JNIHandles::make_local(env, v); 192#if INCLUDE_ALL_GCS 193 // We could be accessing the referent field in a reference 194 // object. If G1 is enabled then we need to register non-null 195 // referent with the SATB barrier. 196 if (UseG1GC) { 197 bool needs_barrier = false; 198 199 if (ret != NULL) { 200 if (offset == java_lang_ref_Reference::referent_offset && obj != NULL) { 201 oop o = JNIHandles::resolve(obj); 202 Klass* k = o->klass(); 203 if (InstanceKlass::cast(k)->reference_type() != REF_NONE) { 204 assert(InstanceKlass::cast(k)->is_subclass_of(SystemDictionary::Reference_klass()), "sanity"); 205 needs_barrier = true; 206 } 207 } 208 } 209 210 if (needs_barrier) { 211 oop referent = JNIHandles::resolve(ret); 212 G1SATBCardTableModRefBS::enqueue(referent); 213 } 214 } 215#endif // INCLUDE_ALL_GCS 216 return ret; 217UNSAFE_END 218 219UNSAFE_ENTRY(void, Unsafe_SetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) 220 UnsafeWrapper("Unsafe_SetObject"); 221 oop x = JNIHandles::resolve(x_h); 222 oop p = JNIHandles::resolve(obj); 223 if (UseCompressedOops) { 224 oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x); 225 } else { 226 oop_store((oop*)index_oop_from_field_offset_long(p, offset), x); 227 } 228UNSAFE_END 229 230UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) 231 UnsafeWrapper("Unsafe_GetObjectVolatile"); 232 oop p = JNIHandles::resolve(obj); 233 void* addr = index_oop_from_field_offset_long(p, offset); 234 volatile oop v; 235 if (UseCompressedOops) { 236 volatile narrowOop n = *(volatile narrowOop*) addr; 237 (void)const_cast<oop&>(v = oopDesc::decode_heap_oop(n)); 238 } else { 239 (void)const_cast<oop&>(v = *(volatile oop*) addr); 240 } 241 OrderAccess::acquire(); 242 return JNIHandles::make_local(env, v); 243UNSAFE_END 244 245UNSAFE_ENTRY(void, Unsafe_SetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) 246 UnsafeWrapper("Unsafe_SetObjectVolatile"); 247 oop x = JNIHandles::resolve(x_h); 248 oop p = JNIHandles::resolve(obj); 249 void* addr = index_oop_from_field_offset_long(p, offset); 250 OrderAccess::release(); 251 if (UseCompressedOops) { 252 oop_store((narrowOop*)addr, x); 253 } else { 254 oop_store((oop*)addr, x); 255 } 256 OrderAccess::fence(); 257UNSAFE_END 258 259UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) 260 UnsafeWrapper("Unsafe_GetUncompressedObject"); 261 oop v = *(oop*) (address) addr; 262 return JNIHandles::make_local(env, v); 263UNSAFE_END 264 265UNSAFE_ENTRY(jclass, Unsafe_GetJavaMirror(JNIEnv *env, jobject unsafe, jlong metaspace_klass)) 266 UnsafeWrapper("Unsafe_GetJavaMirror"); 267 Klass* klass = (Klass*) (address) metaspace_klass; 268 return (jclass) JNIHandles::make_local(klass->java_mirror()); 269UNSAFE_END 270 271UNSAFE_ENTRY(jlong, Unsafe_GetKlassPointer(JNIEnv *env, jobject unsafe, jobject obj)) 272 UnsafeWrapper("Unsafe_GetKlassPointer"); 273 oop o = JNIHandles::resolve(obj); 274 jlong klass = (jlong) (address) o->klass(); 275 return klass; 276UNSAFE_END 277 278#ifndef SUPPORTS_NATIVE_CX8 279 280// VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'. 281// 282// On platforms which do not support atomic compare-and-swap of jlong (8 byte) 283// values we have to use a lock-based scheme to enforce atomicity. This has to be 284// applied to all Unsafe operations that set the value of a jlong field. Even so 285// the compareAndSwapLong operation will not be atomic with respect to direct stores 286// to the field from Java code. It is important therefore that any Java code that 287// utilizes these Unsafe jlong operations does not perform direct stores. To permit 288// direct loads of the field from Java code we must also use Atomic::store within the 289// locked regions. And for good measure, in case there are direct stores, we also 290// employ Atomic::load within those regions. Note that the field in question must be 291// volatile and so must have atomic load/store accesses applied at the Java level. 292// 293// The locking scheme could utilize a range of strategies for controlling the locking 294// granularity: from a lock per-field through to a single global lock. The latter is 295// the simplest and is used for the current implementation. Note that the Java object 296// that contains the field, can not, in general, be used for locking. To do so can lead 297// to deadlocks as we may introduce locking into what appears to the Java code to be a 298// lock-free path. 299// 300// As all the locked-regions are very short and themselves non-blocking we can treat 301// them as leaf routines and elide safepoint checks (ie we don't perform any thread 302// state transitions even when blocking for the lock). Note that if we do choose to 303// add safepoint checks and thread state transitions, we must ensure that we calculate 304// the address of the field _after_ we have acquired the lock, else the object may have 305// been moved by the GC 306 307UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) 308 UnsafeWrapper("Unsafe_GetLongVolatile"); 309 { 310 if (VM_Version::supports_cx8()) { 311 GET_FIELD_VOLATILE(obj, offset, jlong, v); 312 return v; 313 } 314 else { 315 Handle p (THREAD, JNIHandles::resolve(obj)); 316 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); 317 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); 318 jlong value = Atomic::load(addr); 319 return value; 320 } 321 } 322UNSAFE_END 323 324UNSAFE_ENTRY(void, Unsafe_SetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) 325 UnsafeWrapper("Unsafe_SetLongVolatile"); 326 { 327 if (VM_Version::supports_cx8()) { 328 SET_FIELD_VOLATILE(obj, offset, jlong, x); 329 } 330 else { 331 Handle p (THREAD, JNIHandles::resolve(obj)); 332 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); 333 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); 334 Atomic::store(x, addr); 335 } 336 } 337UNSAFE_END 338 339#endif // not SUPPORTS_NATIVE_CX8 340 341UNSAFE_ENTRY(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe)) 342 UnsafeWrapper("Unsafe_IsBigEndian0"); 343 { 344#ifdef VM_LITTLE_ENDIAN 345 return false; 346#else 347 return true; 348#endif 349 } 350UNSAFE_END 351 352UNSAFE_ENTRY(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe)) 353 UnsafeWrapper("Unsafe_UnalignedAccess0"); 354 { 355 return UseUnalignedAccesses; 356 } 357UNSAFE_END 358 359#define DEFINE_GETSETOOP(jboolean, Boolean) \ 360 \ 361UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset)) \ 362 UnsafeWrapper("Unsafe_Get"#Boolean); \ 363 if (obj == NULL) THROW_0(vmSymbols::java_lang_NullPointerException()); \ 364 GET_FIELD(obj, offset, jboolean, v); \ 365 return v; \ 366UNSAFE_END \ 367 \ 368UNSAFE_ENTRY(void, Unsafe_Set##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset, jboolean x)) \ 369 UnsafeWrapper("Unsafe_Set"#Boolean); \ 370 if (obj == NULL) THROW(vmSymbols::java_lang_NullPointerException()); \ 371 SET_FIELD(obj, offset, jboolean, x); \ 372UNSAFE_END \ 373 \ 374UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \ 375 UnsafeWrapper("Unsafe_Get"#Boolean); \ 376 GET_FIELD(obj, offset, jboolean, v); \ 377 return v; \ 378UNSAFE_END \ 379 \ 380UNSAFE_ENTRY(void, Unsafe_Set##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \ 381 UnsafeWrapper("Unsafe_Set"#Boolean); \ 382 SET_FIELD(obj, offset, jboolean, x); \ 383UNSAFE_END \ 384 \ 385// END DEFINE_GETSETOOP. 386 387DEFINE_GETSETOOP(jboolean, Boolean) 388DEFINE_GETSETOOP(jbyte, Byte) 389DEFINE_GETSETOOP(jshort, Short); 390DEFINE_GETSETOOP(jchar, Char); 391DEFINE_GETSETOOP(jint, Int); 392DEFINE_GETSETOOP(jlong, Long); 393DEFINE_GETSETOOP(jfloat, Float); 394DEFINE_GETSETOOP(jdouble, Double); 395 396#undef DEFINE_GETSETOOP 397 398#define DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) \ 399 \ 400UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \ 401 UnsafeWrapper("Unsafe_Get"#Boolean); \ 402 GET_FIELD_VOLATILE(obj, offset, jboolean, v); \ 403 return v; \ 404UNSAFE_END \ 405 \ 406UNSAFE_ENTRY(void, Unsafe_Set##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \ 407 UnsafeWrapper("Unsafe_Set"#Boolean); \ 408 SET_FIELD_VOLATILE(obj, offset, jboolean, x); \ 409UNSAFE_END \ 410 \ 411// END DEFINE_GETSETOOP_VOLATILE. 412 413DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) 414DEFINE_GETSETOOP_VOLATILE(jbyte, Byte) 415DEFINE_GETSETOOP_VOLATILE(jshort, Short); 416DEFINE_GETSETOOP_VOLATILE(jchar, Char); 417DEFINE_GETSETOOP_VOLATILE(jint, Int); 418DEFINE_GETSETOOP_VOLATILE(jfloat, Float); 419DEFINE_GETSETOOP_VOLATILE(jdouble, Double); 420 421#ifdef SUPPORTS_NATIVE_CX8 422DEFINE_GETSETOOP_VOLATILE(jlong, Long); 423#endif 424 425#undef DEFINE_GETSETOOP_VOLATILE 426 427// The non-intrinsified versions of setOrdered just use setVolatile 428 429UNSAFE_ENTRY(void, Unsafe_SetOrderedInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint x)) 430 UnsafeWrapper("Unsafe_SetOrderedInt"); 431 SET_FIELD_VOLATILE(obj, offset, jint, x); 432UNSAFE_END 433 434UNSAFE_ENTRY(void, Unsafe_SetOrderedObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) 435 UnsafeWrapper("Unsafe_SetOrderedObject"); 436 oop x = JNIHandles::resolve(x_h); 437 oop p = JNIHandles::resolve(obj); 438 void* addr = index_oop_from_field_offset_long(p, offset); 439 OrderAccess::release(); 440 if (UseCompressedOops) { 441 oop_store((narrowOop*)addr, x); 442 } else { 443 oop_store((oop*)addr, x); 444 } 445 OrderAccess::fence(); 446UNSAFE_END 447 448UNSAFE_ENTRY(void, Unsafe_SetOrderedLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) 449 UnsafeWrapper("Unsafe_SetOrderedLong"); 450#ifdef SUPPORTS_NATIVE_CX8 451 SET_FIELD_VOLATILE(obj, offset, jlong, x); 452#else 453 // Keep old code for platforms which may not have atomic long (8 bytes) instructions 454 { 455 if (VM_Version::supports_cx8()) { 456 SET_FIELD_VOLATILE(obj, offset, jlong, x); 457 } 458 else { 459 Handle p (THREAD, JNIHandles::resolve(obj)); 460 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); 461 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); 462 Atomic::store(x, addr); 463 } 464 } 465#endif 466UNSAFE_END 467 468UNSAFE_ENTRY(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) 469 UnsafeWrapper("Unsafe_LoadFence"); 470 OrderAccess::acquire(); 471UNSAFE_END 472 473UNSAFE_ENTRY(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) 474 UnsafeWrapper("Unsafe_StoreFence"); 475 OrderAccess::release(); 476UNSAFE_END 477 478UNSAFE_ENTRY(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) 479 UnsafeWrapper("Unsafe_FullFence"); 480 OrderAccess::fence(); 481UNSAFE_END 482 483////// Data in the C heap. 484 485// Note: These do not throw NullPointerException for bad pointers. 486// They just crash. Only a oop base pointer can generate a NullPointerException. 487// 488#define DEFINE_GETSETNATIVE(java_type, Type, native_type) \ 489 \ 490UNSAFE_ENTRY(java_type, Unsafe_GetNative##Type(JNIEnv *env, jobject unsafe, jlong addr)) \ 491 UnsafeWrapper("Unsafe_GetNative"#Type); \ 492 void* p = addr_from_java(addr); \ 493 JavaThread* t = JavaThread::current(); \ 494 t->set_doing_unsafe_access(true); \ 495 java_type x = *(volatile native_type*)p; \ 496 t->set_doing_unsafe_access(false); \ 497 return x; \ 498UNSAFE_END \ 499 \ 500UNSAFE_ENTRY(void, Unsafe_SetNative##Type(JNIEnv *env, jobject unsafe, jlong addr, java_type x)) \ 501 UnsafeWrapper("Unsafe_SetNative"#Type); \ 502 JavaThread* t = JavaThread::current(); \ 503 t->set_doing_unsafe_access(true); \ 504 void* p = addr_from_java(addr); \ 505 *(volatile native_type*)p = x; \ 506 t->set_doing_unsafe_access(false); \ 507UNSAFE_END \ 508 \ 509// END DEFINE_GETSETNATIVE. 510 511DEFINE_GETSETNATIVE(jbyte, Byte, signed char) 512DEFINE_GETSETNATIVE(jshort, Short, signed short); 513DEFINE_GETSETNATIVE(jchar, Char, unsigned short); 514DEFINE_GETSETNATIVE(jint, Int, jint); 515// no long -- handled specially 516DEFINE_GETSETNATIVE(jfloat, Float, float); 517DEFINE_GETSETNATIVE(jdouble, Double, double); 518 519#undef DEFINE_GETSETNATIVE 520 521UNSAFE_ENTRY(jlong, Unsafe_GetNativeLong(JNIEnv *env, jobject unsafe, jlong addr)) 522 UnsafeWrapper("Unsafe_GetNativeLong"); 523 JavaThread* t = JavaThread::current(); 524 // We do it this way to avoid problems with access to heap using 64 525 // bit loads, as jlong in heap could be not 64-bit aligned, and on 526 // some CPUs (SPARC) it leads to SIGBUS. 527 t->set_doing_unsafe_access(true); 528 void* p = addr_from_java(addr); 529 jlong x; 530 if (((intptr_t)p & 7) == 0) { 531 // jlong is aligned, do a volatile access 532 x = *(volatile jlong*)p; 533 } else { 534 jlong_accessor acc; 535 acc.words[0] = ((volatile jint*)p)[0]; 536 acc.words[1] = ((volatile jint*)p)[1]; 537 x = acc.long_value; 538 } 539 t->set_doing_unsafe_access(false); 540 return x; 541UNSAFE_END 542 543UNSAFE_ENTRY(void, Unsafe_SetNativeLong(JNIEnv *env, jobject unsafe, jlong addr, jlong x)) 544 UnsafeWrapper("Unsafe_SetNativeLong"); 545 JavaThread* t = JavaThread::current(); 546 // see comment for Unsafe_GetNativeLong 547 t->set_doing_unsafe_access(true); 548 void* p = addr_from_java(addr); 549 if (((intptr_t)p & 7) == 0) { 550 // jlong is aligned, do a volatile access 551 *(volatile jlong*)p = x; 552 } else { 553 jlong_accessor acc; 554 acc.long_value = x; 555 ((volatile jint*)p)[0] = acc.words[0]; 556 ((volatile jint*)p)[1] = acc.words[1]; 557 } 558 t->set_doing_unsafe_access(false); 559UNSAFE_END 560 561 562UNSAFE_ENTRY(jlong, Unsafe_GetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr)) 563 UnsafeWrapper("Unsafe_GetNativeAddress"); 564 void* p = addr_from_java(addr); 565 return addr_to_java(*(void**)p); 566UNSAFE_END 567 568UNSAFE_ENTRY(void, Unsafe_SetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr, jlong x)) 569 UnsafeWrapper("Unsafe_SetNativeAddress"); 570 void* p = addr_from_java(addr); 571 *(void**)p = addr_from_java(x); 572UNSAFE_END 573 574 575////// Allocation requests 576 577UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) 578 UnsafeWrapper("Unsafe_AllocateInstance"); 579 { 580 ThreadToNativeFromVM ttnfv(thread); 581 return env->AllocObject(cls); 582 } 583UNSAFE_END 584 585UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory(JNIEnv *env, jobject unsafe, jlong size)) 586 UnsafeWrapper("Unsafe_AllocateMemory"); 587 size_t sz = (size_t)size; 588 if (sz != (julong)size || size < 0) { 589 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 590 } 591 if (sz == 0) { 592 return 0; 593 } 594 sz = round_to(sz, HeapWordSize); 595 void* x = os::malloc(sz, mtInternal); 596 if (x == NULL) { 597 THROW_0(vmSymbols::java_lang_OutOfMemoryError()); 598 } 599 //Copy::fill_to_words((HeapWord*)x, sz / HeapWordSize); 600 return addr_to_java(x); 601UNSAFE_END 602 603UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) 604 UnsafeWrapper("Unsafe_ReallocateMemory"); 605 void* p = addr_from_java(addr); 606 size_t sz = (size_t)size; 607 if (sz != (julong)size || size < 0) { 608 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 609 } 610 if (sz == 0) { 611 os::free(p); 612 return 0; 613 } 614 sz = round_to(sz, HeapWordSize); 615 void* x = (p == NULL) ? os::malloc(sz, mtInternal) : os::realloc(p, sz, mtInternal); 616 if (x == NULL) { 617 THROW_0(vmSymbols::java_lang_OutOfMemoryError()); 618 } 619 return addr_to_java(x); 620UNSAFE_END 621 622UNSAFE_ENTRY(void, Unsafe_FreeMemory(JNIEnv *env, jobject unsafe, jlong addr)) 623 UnsafeWrapper("Unsafe_FreeMemory"); 624 void* p = addr_from_java(addr); 625 if (p == NULL) { 626 return; 627 } 628 os::free(p); 629UNSAFE_END 630 631UNSAFE_ENTRY(void, Unsafe_SetMemory(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) 632 UnsafeWrapper("Unsafe_SetMemory"); 633 size_t sz = (size_t)size; 634 if (sz != (julong)size || size < 0) { 635 THROW(vmSymbols::java_lang_IllegalArgumentException()); 636 } 637 oop base = JNIHandles::resolve(obj); 638 void* p = index_oop_from_field_offset_long(base, offset); 639 Copy::fill_to_memory_atomic(p, sz, value); 640UNSAFE_END 641 642UNSAFE_ENTRY(void, Unsafe_CopyMemory(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) 643 UnsafeWrapper("Unsafe_CopyMemory"); 644 if (size == 0) { 645 return; 646 } 647 size_t sz = (size_t)size; 648 if (sz != (julong)size || size < 0) { 649 THROW(vmSymbols::java_lang_IllegalArgumentException()); 650 } 651 oop srcp = JNIHandles::resolve(srcObj); 652 oop dstp = JNIHandles::resolve(dstObj); 653 if (dstp != NULL && !dstp->is_typeArray()) { 654 // NYI: This works only for non-oop arrays at present. 655 // Generalizing it would be reasonable, but requires card marking. 656 // Also, autoboxing a Long from 0L in copyMemory(x,y, 0L,z, n) would be bad. 657 THROW(vmSymbols::java_lang_IllegalArgumentException()); 658 } 659 void* src = index_oop_from_field_offset_long(srcp, srcOffset); 660 void* dst = index_oop_from_field_offset_long(dstp, dstOffset); 661 Copy::conjoint_memory_atomic(src, dst, sz); 662UNSAFE_END 663 664 665////// Random queries 666 667// See comment at file start about UNSAFE_LEAF 668//UNSAFE_LEAF(jint, Unsafe_AddressSize()) 669UNSAFE_ENTRY(jint, Unsafe_AddressSize(JNIEnv *env, jobject unsafe)) 670 UnsafeWrapper("Unsafe_AddressSize"); 671 return sizeof(void*); 672UNSAFE_END 673 674// See comment at file start about UNSAFE_LEAF 675//UNSAFE_LEAF(jint, Unsafe_PageSize()) 676UNSAFE_ENTRY(jint, Unsafe_PageSize(JNIEnv *env, jobject unsafe)) 677 UnsafeWrapper("Unsafe_PageSize"); 678 return os::vm_page_size(); 679UNSAFE_END 680 681jint find_field_offset(jobject field, int must_be_static, TRAPS) { 682 if (field == NULL) { 683 THROW_0(vmSymbols::java_lang_NullPointerException()); 684 } 685 686 oop reflected = JNIHandles::resolve_non_null(field); 687 oop mirror = java_lang_reflect_Field::clazz(reflected); 688 Klass* k = java_lang_Class::as_Klass(mirror); 689 int slot = java_lang_reflect_Field::slot(reflected); 690 int modifiers = java_lang_reflect_Field::modifiers(reflected); 691 692 if (must_be_static >= 0) { 693 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0); 694 if (must_be_static != really_is_static) { 695 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 696 } 697 } 698 699 int offset = InstanceKlass::cast(k)->field_offset(slot); 700 return field_offset_from_byte_offset(offset); 701} 702 703UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset(JNIEnv *env, jobject unsafe, jobject field)) 704 UnsafeWrapper("Unsafe_ObjectFieldOffset"); 705 return find_field_offset(field, 0, THREAD); 706UNSAFE_END 707 708UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset(JNIEnv *env, jobject unsafe, jobject field)) 709 UnsafeWrapper("Unsafe_StaticFieldOffset"); 710 return find_field_offset(field, 1, THREAD); 711UNSAFE_END 712 713UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBaseFromField(JNIEnv *env, jobject unsafe, jobject field)) 714 UnsafeWrapper("Unsafe_StaticFieldBase"); 715 // Note: In this VM implementation, a field address is always a short 716 // offset from the base of a a klass metaobject. Thus, the full dynamic 717 // range of the return type is never used. However, some implementations 718 // might put the static field inside an array shared by many classes, 719 // or even at a fixed address, in which case the address could be quite 720 // large. In that last case, this function would return NULL, since 721 // the address would operate alone, without any base pointer. 722 723 if (field == NULL) THROW_0(vmSymbols::java_lang_NullPointerException()); 724 725 oop reflected = JNIHandles::resolve_non_null(field); 726 oop mirror = java_lang_reflect_Field::clazz(reflected); 727 int modifiers = java_lang_reflect_Field::modifiers(reflected); 728 729 if ((modifiers & JVM_ACC_STATIC) == 0) { 730 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 731 } 732 733 return JNIHandles::make_local(env, mirror); 734UNSAFE_END 735 736UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) { 737 UnsafeWrapper("Unsafe_EnsureClassInitialized"); 738 if (clazz == NULL) { 739 THROW(vmSymbols::java_lang_NullPointerException()); 740 } 741 oop mirror = JNIHandles::resolve_non_null(clazz); 742 743 Klass* klass = java_lang_Class::as_Klass(mirror); 744 if (klass != NULL && klass->should_be_initialized()) { 745 InstanceKlass* k = InstanceKlass::cast(klass); 746 k->initialize(CHECK); 747 } 748} 749UNSAFE_END 750 751UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) { 752 UnsafeWrapper("Unsafe_ShouldBeInitialized"); 753 if (clazz == NULL) { 754 THROW_(vmSymbols::java_lang_NullPointerException(), false); 755 } 756 oop mirror = JNIHandles::resolve_non_null(clazz); 757 Klass* klass = java_lang_Class::as_Klass(mirror); 758 if (klass != NULL && klass->should_be_initialized()) { 759 return true; 760 } 761 return false; 762} 763UNSAFE_END 764 765static void getBaseAndScale(int& base, int& scale, jclass acls, TRAPS) { 766 if (acls == NULL) { 767 THROW(vmSymbols::java_lang_NullPointerException()); 768 } 769 oop mirror = JNIHandles::resolve_non_null(acls); 770 Klass* k = java_lang_Class::as_Klass(mirror); 771 if (k == NULL || !k->oop_is_array()) { 772 THROW(vmSymbols::java_lang_InvalidClassException()); 773 } else if (k->oop_is_objArray()) { 774 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT); 775 scale = heapOopSize; 776 } else if (k->oop_is_typeArray()) { 777 TypeArrayKlass* tak = TypeArrayKlass::cast(k); 778 base = tak->array_header_in_bytes(); 779 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok"); 780 scale = (1 << tak->log2_element_size()); 781 } else { 782 ShouldNotReachHere(); 783 } 784} 785 786UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset(JNIEnv *env, jobject unsafe, jclass acls)) 787 UnsafeWrapper("Unsafe_ArrayBaseOffset"); 788 int base, scale; 789 getBaseAndScale(base, scale, acls, CHECK_0); 790 return field_offset_from_byte_offset(base); 791UNSAFE_END 792 793 794UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale(JNIEnv *env, jobject unsafe, jclass acls)) 795 UnsafeWrapper("Unsafe_ArrayIndexScale"); 796 int base, scale; 797 getBaseAndScale(base, scale, acls, CHECK_0); 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); 813UNSAFE_END 814 815 816static inline void throw_new(JNIEnv *env, const char *ename) { 817 char buf[100]; 818 jio_snprintf(buf, 100, "%s%s", "java/lang/", ename); 819 jclass cls = env->FindClass(buf); 820 if (env->ExceptionCheck()) { 821 env->ExceptionClear(); 822 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf); 823 return; 824 } 825 char* msg = NULL; 826 env->ThrowNew(cls, msg); 827} 828 829static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) { 830 { 831 // Code lifted from JDK 1.3 ClassLoader.c 832 833 jbyte *body; 834 char *utfName; 835 jclass result = 0; 836 char buf[128]; 837 838 if (UsePerfData) { 839 ClassLoader::unsafe_defineClassCallCounter()->inc(); 840 } 841 842 if (data == NULL) { 843 throw_new(env, "NullPointerException"); 844 return 0; 845 } 846 847 /* Work around 4153825. malloc crashes on Solaris when passed a 848 * negative size. 849 */ 850 if (length < 0) { 851 throw_new(env, "ArrayIndexOutOfBoundsException"); 852 return 0; 853 } 854 855 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal); 856 857 if (body == 0) { 858 throw_new(env, "OutOfMemoryError"); 859 return 0; 860 } 861 862 env->GetByteArrayRegion(data, offset, length, body); 863 864 if (env->ExceptionOccurred()) 865 goto free_body; 866 867 if (name != NULL) { 868 uint len = env->GetStringUTFLength(name); 869 int unicode_len = env->GetStringLength(name); 870 if (len >= sizeof(buf)) { 871 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal); 872 if (utfName == NULL) { 873 throw_new(env, "OutOfMemoryError"); 874 goto free_body; 875 } 876 } else { 877 utfName = buf; 878 } 879 env->GetStringUTFRegion(name, 0, unicode_len, utfName); 880 //VerifyFixClassname(utfName); 881 for (uint i = 0; i < len; i++) { 882 if (utfName[i] == '.') utfName[i] = '/'; 883 } 884 } else { 885 utfName = NULL; 886 } 887 888 result = JVM_DefineClass(env, utfName, loader, body, length, pd); 889 890 if (utfName && utfName != buf) 891 FREE_C_HEAP_ARRAY(char, utfName); 892 893 free_body: 894 FREE_C_HEAP_ARRAY(jbyte, body); 895 return result; 896 } 897} 898 899 900UNSAFE_ENTRY(jclass, Unsafe_DefineClass(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) 901 UnsafeWrapper("Unsafe_DefineClass"); 902 { 903 ThreadToNativeFromVM ttnfv(thread); 904 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd); 905 } 906UNSAFE_END 907 908 909// define a class but do not make it known to the class loader or system dictionary 910// - host_class: supplies context for linkage, access control, protection domain, and class loader 911// - data: bytes of a class file, a raw memory address (length gives the number of bytes) 912// - cp_patches: where non-null entries exist, they replace corresponding CP entries in data 913 914// When you load an anonymous class U, it works as if you changed its name just before loading, 915// to a name that you will never use again. Since the name is lost, no other class can directly 916// link to any member of U. Just after U is loaded, the only way to use it is reflectively, 917// through java.lang.Class methods like Class.newInstance. 918 919// Access checks for linkage sites within U continue to follow the same rules as for named classes. 920// The package of an anonymous class is given by the package qualifier on the name under which it was loaded. 921// An anonymous class also has special privileges to access any member of its host class. 922// This is the main reason why this loading operation is unsafe. The purpose of this is to 923// allow language implementations to simulate "open classes"; a host class in effect gets 924// new code when an anonymous class is loaded alongside it. A less convenient but more 925// standard way to do this is with reflection, which can also be set to ignore access 926// restrictions. 927 928// Access into an anonymous class is possible only through reflection. Therefore, there 929// are no special access rules for calling into an anonymous class. The relaxed access 930// rule for the host class is applied in the opposite direction: A host class reflectively 931// access one of its anonymous classes. 932 933// If you load the same bytecodes twice, you get two different classes. You can reload 934// the same bytecodes with or without varying CP patches. 935 936// By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1. 937// The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is). 938// The CONSTANT_Class entry for that name can be patched to refer directly to U1. 939 940// This allows, for example, U2 to use U1 as a superclass or super-interface, or as 941// an outer class (so that U2 is an anonymous inner class of anonymous U1). 942// It is not possible for a named class, or an older anonymous class, to refer by 943// name (via its CP) to a newer anonymous class. 944 945// CP patching may also be used to modify (i.e., hack) the names of methods, classes, 946// or type descriptors used in the loaded anonymous class. 947 948// Finally, CP patching may be used to introduce "live" objects into the constant pool, 949// instead of "dead" strings. A compiled statement like println((Object)"hello") can 950// be changed to println(greeting), where greeting is an arbitrary object created before 951// the anonymous class is loaded. This is useful in dynamic languages, in which 952// various kinds of metaobjects must be introduced as constants into bytecode. 953// Note the cast (Object), which tells the verifier to expect an arbitrary object, 954// not just a literal string. For such ldc instructions, the verifier uses the 955// type Object instead of String, if the loaded constant is not in fact a String. 956 957static instanceKlassHandle 958Unsafe_DefineAnonymousClass_impl(JNIEnv *env, 959 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh, 960 HeapWord* *temp_alloc, 961 TRAPS) { 962 963 if (UsePerfData) { 964 ClassLoader::unsafe_defineClassCallCounter()->inc(); 965 } 966 967 if (data == NULL) { 968 THROW_0(vmSymbols::java_lang_NullPointerException()); 969 } 970 971 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length(); 972 jint word_length = (length + sizeof(HeapWord)-1) / sizeof(HeapWord); 973 HeapWord* body = NEW_C_HEAP_ARRAY(HeapWord, word_length, mtInternal); 974 if (body == NULL) { 975 THROW_0(vmSymbols::java_lang_OutOfMemoryError()); 976 } 977 978 // caller responsible to free it: 979 (*temp_alloc) = body; 980 981 { 982 jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0); 983 Copy::conjoint_words((HeapWord*) array_base, body, word_length); 984 } 985 986 u1* class_bytes = (u1*) body; 987 int class_bytes_length = (int) length; 988 if (class_bytes_length < 0) class_bytes_length = 0; 989 if (class_bytes == NULL 990 || host_class == NULL 991 || length != class_bytes_length) 992 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 993 994 objArrayHandle cp_patches_h; 995 if (cp_patches_jh != NULL) { 996 oop p = JNIHandles::resolve_non_null(cp_patches_jh); 997 if (!p->is_objArray()) 998 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 999 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p); 1000 } 1001 1002 KlassHandle host_klass(THREAD, java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class))); 1003 const char* host_source = host_klass->external_name(); 1004 Handle host_loader(THREAD, host_klass->class_loader()); 1005 Handle host_domain(THREAD, host_klass->protection_domain()); 1006 1007 GrowableArray<Handle>* cp_patches = NULL; 1008 if (cp_patches_h.not_null()) { 1009 int alen = cp_patches_h->length(); 1010 for (int i = alen-1; i >= 0; i--) { 1011 oop p = cp_patches_h->obj_at(i); 1012 if (p != NULL) { 1013 Handle patch(THREAD, p); 1014 if (cp_patches == NULL) 1015 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle()); 1016 cp_patches->at_put(i, patch); 1017 } 1018 } 1019 } 1020 1021 ClassFileStream st(class_bytes, class_bytes_length, (char*) host_source); 1022 1023 instanceKlassHandle anon_klass; 1024 { 1025 Symbol* no_class_name = NULL; 1026 Klass* anonk = SystemDictionary::parse_stream(no_class_name, 1027 host_loader, host_domain, 1028 &st, host_klass, cp_patches, 1029 CHECK_NULL); 1030 if (anonk == NULL) return NULL; 1031 anon_klass = instanceKlassHandle(THREAD, anonk); 1032 } 1033 1034 return anon_klass; 1035} 1036 1037UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) 1038{ 1039 instanceKlassHandle anon_klass; 1040 jobject res_jh = NULL; 1041 1042 UnsafeWrapper("Unsafe_DefineAnonymousClass"); 1043 ResourceMark rm(THREAD); 1044 1045 HeapWord* temp_alloc = NULL; 1046 1047 anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, 1048 cp_patches_jh, 1049 &temp_alloc, THREAD); 1050 if (anon_klass() != NULL) 1051 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror()); 1052 1053 // try/finally clause: 1054 if (temp_alloc != NULL) { 1055 FREE_C_HEAP_ARRAY(HeapWord, temp_alloc); 1056 } 1057 1058 // The anonymous class loader data has been artificially been kept alive to 1059 // this point. The mirror and any instances of this class have to keep 1060 // it alive afterwards. 1061 if (anon_klass() != NULL) { 1062 anon_klass->class_loader_data()->set_keep_alive(false); 1063 } 1064 1065 // let caller initialize it as needed... 1066 1067 return (jclass) res_jh; 1068} 1069UNSAFE_END 1070 1071 1072 1073UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) 1074 UnsafeWrapper("Unsafe_ThrowException"); 1075 { 1076 ThreadToNativeFromVM ttnfv(thread); 1077 env->Throw(thr); 1078 } 1079UNSAFE_END 1080 1081// JSR166 ------------------------------------------------------------------ 1082 1083UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) 1084 UnsafeWrapper("Unsafe_CompareAndSwapObject"); 1085 oop x = JNIHandles::resolve(x_h); 1086 oop e = JNIHandles::resolve(e_h); 1087 oop p = JNIHandles::resolve(obj); 1088 HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset); 1089 oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true); 1090 jboolean success = (res == e); 1091 if (success) 1092 update_barrier_set((void*)addr, x); 1093 return success; 1094UNSAFE_END 1095 1096UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) 1097 UnsafeWrapper("Unsafe_CompareAndSwapInt"); 1098 oop p = JNIHandles::resolve(obj); 1099 jint* addr = (jint *) index_oop_from_field_offset_long(p, offset); 1100 return (jint)(Atomic::cmpxchg(x, addr, e)) == e; 1101UNSAFE_END 1102 1103UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) 1104 UnsafeWrapper("Unsafe_CompareAndSwapLong"); 1105 Handle p (THREAD, JNIHandles::resolve(obj)); 1106 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset)); 1107#ifdef SUPPORTS_NATIVE_CX8 1108 return (jlong)(Atomic::cmpxchg(x, addr, e)) == e; 1109#else 1110 if (VM_Version::supports_cx8()) 1111 return (jlong)(Atomic::cmpxchg(x, addr, e)) == e; 1112 else { 1113 jboolean success = false; 1114 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag); 1115 jlong val = Atomic::load(addr); 1116 if (val == e) { Atomic::store(x, addr); success = true; } 1117 return success; 1118 } 1119#endif 1120UNSAFE_END 1121 1122UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) 1123 UnsafeWrapper("Unsafe_Park"); 1124 EventThreadPark event; 1125 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time); 1126 1127 JavaThreadParkedState jtps(thread, time != 0); 1128 thread->parker()->park(isAbsolute != 0, time); 1129 1130 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker()); 1131 if (event.should_commit()) { 1132 oop obj = thread->current_park_blocker(); 1133 event.set_klass((obj != NULL) ? obj->klass() : NULL); 1134 event.set_timeout(time); 1135 event.set_address((obj != NULL) ? (TYPE_ADDRESS) cast_from_oop<uintptr_t>(obj) : 0); 1136 event.commit(); 1137 } 1138UNSAFE_END 1139 1140UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) 1141 UnsafeWrapper("Unsafe_Unpark"); 1142 Parker* p = NULL; 1143 if (jthread != NULL) { 1144 oop java_thread = JNIHandles::resolve_non_null(jthread); 1145 if (java_thread != NULL) { 1146 jlong lp = java_lang_Thread::park_event(java_thread); 1147 if (lp != 0) { 1148 // This cast is OK even though the jlong might have been read 1149 // non-atomically on 32bit systems, since there, one word will 1150 // always be zero anyway and the value set is always the same 1151 p = (Parker*)addr_from_java(lp); 1152 } else { 1153 // Grab lock if apparently null or using older version of library 1154 MutexLocker mu(Threads_lock); 1155 java_thread = JNIHandles::resolve_non_null(jthread); 1156 if (java_thread != NULL) { 1157 JavaThread* thr = java_lang_Thread::thread(java_thread); 1158 if (thr != NULL) { 1159 p = thr->parker(); 1160 if (p != NULL) { // Bind to Java thread for next time. 1161 java_lang_Thread::set_park_event(java_thread, addr_to_java(p)); 1162 } 1163 } 1164 } 1165 } 1166 } 1167 } 1168 if (p != NULL) { 1169 HOTSPOT_THREAD_UNPARK((uintptr_t) p); 1170 p->unpark(); 1171 } 1172UNSAFE_END 1173 1174UNSAFE_ENTRY(jint, Unsafe_Loadavg(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) 1175 UnsafeWrapper("Unsafe_Loadavg"); 1176 const int max_nelem = 3; 1177 double la[max_nelem]; 1178 jint ret; 1179 1180 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg)); 1181 assert(a->is_typeArray(), "must be type array"); 1182 1183 if (nelem < 0 || nelem > max_nelem || a->length() < nelem) { 1184 ThreadToNativeFromVM ttnfv(thread); 1185 throw_new(env, "ArrayIndexOutOfBoundsException"); 1186 return -1; 1187 } 1188 1189 ret = os::loadavg(la, nelem); 1190 if (ret == -1) return -1; 1191 1192 // if successful, ret is the number of samples actually retrieved. 1193 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value"); 1194 switch(ret) { 1195 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through 1196 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through 1197 case 1: a->double_at_put(0, (jdouble)la[0]); break; 1198 } 1199 return ret; 1200UNSAFE_END 1201 1202 1203/// JVM_RegisterUnsafeMethods 1204 1205#define ADR "J" 1206 1207#define LANG "Ljava/lang/" 1208 1209#define OBJ LANG "Object;" 1210#define CLS LANG "Class;" 1211#define FLD LANG "reflect/Field;" 1212#define THR LANG "Throwable;" 1213 1214#define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;" 1215#define DAC_Args CLS "[B[" OBJ 1216 1217#define CC (char*) /*cast a literal from (const char*)*/ 1218#define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f) 1219 1220#define DECLARE_GETPUTOOP(Boolean, Z) \ 1221 {CC "get" #Boolean, CC "(" OBJ "J)" #Z, FN_PTR(Unsafe_Get##Boolean)}, \ 1222 {CC "put" #Boolean, CC "(" OBJ "J" #Z ")V", FN_PTR(Unsafe_Set##Boolean)}, \ 1223 {CC "get" #Boolean "Volatile", CC "(" OBJ "J)" #Z, FN_PTR(Unsafe_Get##Boolean##Volatile)}, \ 1224 {CC "put" #Boolean "Volatile", CC "(" OBJ "J" #Z ")V", FN_PTR(Unsafe_Set##Boolean##Volatile)} 1225 1226 1227#define DECLARE_GETPUTNATIVE(Byte, B) \ 1228 {CC "get" #Byte, CC "(" ADR ")" #B, FN_PTR(Unsafe_GetNative##Byte)}, \ 1229 {CC "put" #Byte, CC "(" ADR#B ")V", FN_PTR(Unsafe_SetNative##Byte)} 1230 1231 1232 1233static JNINativeMethod methods[] = { 1234 {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)}, 1235 {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObject)}, 1236 {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)}, 1237 {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetObjectVolatile)}, 1238 1239 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)}, 1240 {CC "getJavaMirror", CC "(" ADR ")" CLS, FN_PTR(Unsafe_GetJavaMirror)}, 1241 {CC "getKlassPointer", CC "(" OBJ ")" ADR, FN_PTR(Unsafe_GetKlassPointer)}, 1242 1243 DECLARE_GETPUTOOP(Boolean, Z), 1244 DECLARE_GETPUTOOP(Byte, B), 1245 DECLARE_GETPUTOOP(Short, S), 1246 DECLARE_GETPUTOOP(Char, C), 1247 DECLARE_GETPUTOOP(Int, I), 1248 DECLARE_GETPUTOOP(Long, J), 1249 DECLARE_GETPUTOOP(Float, F), 1250 DECLARE_GETPUTOOP(Double, D), 1251 1252 DECLARE_GETPUTNATIVE(Byte, B), 1253 DECLARE_GETPUTNATIVE(Short, S), 1254 DECLARE_GETPUTNATIVE(Char, C), 1255 DECLARE_GETPUTNATIVE(Int, I), 1256 DECLARE_GETPUTNATIVE(Long, J), 1257 DECLARE_GETPUTNATIVE(Float, F), 1258 DECLARE_GETPUTNATIVE(Double, D), 1259 1260 {CC "getAddress", CC "(" ADR ")" ADR, FN_PTR(Unsafe_GetNativeAddress)}, 1261 {CC "putAddress", CC "(" ADR "" ADR ")V", FN_PTR(Unsafe_SetNativeAddress)}, 1262 1263 {CC "allocateMemory", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory)}, 1264 {CC "reallocateMemory", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory)}, 1265 {CC "freeMemory", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory)}, 1266 1267 {CC "objectFieldOffset", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset)}, 1268 {CC "staticFieldOffset", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset)}, 1269 {CC "staticFieldBase", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBaseFromField)}, 1270 {CC "ensureClassInitialized",CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized)}, 1271 {CC "arrayBaseOffset", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset)}, 1272 {CC "arrayIndexScale", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale)}, 1273 {CC "addressSize", CC "()I", FN_PTR(Unsafe_AddressSize)}, 1274 {CC "pageSize", CC "()I", FN_PTR(Unsafe_PageSize)}, 1275 1276 {CC "defineClass", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass)}, 1277 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)}, 1278 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)}, 1279 {CC "compareAndSwapObject", CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSwapObject)}, 1280 {CC "compareAndSwapInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSwapInt)}, 1281 {CC "compareAndSwapLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSwapLong)}, 1282 {CC "putOrderedObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_SetOrderedObject)}, 1283 {CC "putOrderedInt", CC "(" OBJ "JI)V", FN_PTR(Unsafe_SetOrderedInt)}, 1284 {CC "putOrderedLong", CC "(" OBJ "JJ)V", FN_PTR(Unsafe_SetOrderedLong)}, 1285 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)}, 1286 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)}, 1287 1288 {CC "getLoadAverage", CC "([DI)I", FN_PTR(Unsafe_Loadavg)}, 1289 1290 {CC "copyMemory", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory)}, 1291 {CC "setMemory", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory)}, 1292 1293 {CC "defineAnonymousClass", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass)}, 1294 1295 {CC "shouldBeInitialized",CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized)}, 1296 1297 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)}, 1298 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)}, 1299 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)}, 1300 1301 {CC "isBigEndian0", CC "()Z", FN_PTR(Unsafe_isBigEndian0)}, 1302 {CC "unalignedAccess0", CC "()Z", FN_PTR(Unsafe_unalignedAccess0)} 1303}; 1304 1305#undef CC 1306#undef FN_PTR 1307 1308#undef ADR 1309#undef LANG 1310#undef OBJ 1311#undef CLS 1312#undef FLD 1313#undef THR 1314#undef DC_Args 1315#undef DAC_Args 1316 1317#undef DECLARE_GETPUTOOP 1318#undef DECLARE_GETPUTNATIVE 1319 1320 1321// This one function is exported, used by NativeLookup. 1322// The Unsafe_xxx functions above are called only from the interpreter. 1323// The optimizer looks at names and signatures to recognize 1324// individual functions. 1325 1326JVM_ENTRY(void, JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafeclass)) 1327 UnsafeWrapper("JVM_RegisterUnsafeMethods"); 1328 { 1329 ThreadToNativeFromVM ttnfv(thread); 1330 1331 int ok = env->RegisterNatives(unsafeclass, methods, sizeof(methods)/sizeof(JNINativeMethod)); 1332 guarantee(ok == 0, "register unsafe natives"); 1333 } 1334JVM_END 1335