1 /* 2 * Copyright (c) 2003, 2020, 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 "jvmtifiles/jvmtiEnv.hpp" 27 #include "memory/resourceArea.hpp" 28 #include "prims/jvmtiEventController.inline.hpp" 29 #include "prims/jvmtiImpl.hpp" 30 #include "prims/jvmtiThreadState.inline.hpp" 31 #include "runtime/safepointVerifiers.hpp" 32 #include "runtime/vframe.hpp" 33 34 // marker for when the stack depth has been reset and is now unknown. 35 // any negative number would work but small ones might obscure an 36 // underrun error. 37 static const int UNKNOWN_STACK_DEPTH = -99; 38 39 /////////////////////////////////////////////////////////////// 40 // 41 // class JvmtiThreadState 42 // 43 // Instances of JvmtiThreadState hang off of each thread. 44 // Thread local storage for JVMTI. 45 // 46 47 JvmtiThreadState *JvmtiThreadState::_head = NULL; 48 49 JvmtiThreadState::JvmtiThreadState(JavaThread* thread) 50 : _thread_event_enable() { 51 assert(JvmtiThreadState_lock->is_locked(), "sanity check"); 52 _thread = thread; 53 _exception_state = ES_CLEARED; 54 _debuggable = true; 55 _hide_single_stepping = false; 56 _hide_level = 0; 57 _pending_step_for_popframe = false; 58 _class_being_redefined = NULL; 59 _class_load_kind = jvmti_class_load_kind_load; 60 _head_env_thread_state = NULL; 61 _dynamic_code_event_collector = NULL; 62 _vm_object_alloc_event_collector = NULL; 63 _sampled_object_alloc_event_collector = NULL; 64 _the_class_for_redefinition_verification = NULL; 65 _scratch_class_for_redefinition_verification = NULL; 66 _cur_stack_depth = UNKNOWN_STACK_DEPTH; 67 68 // JVMTI ForceEarlyReturn support 69 _pending_step_for_earlyret = false; 70 _earlyret_state = earlyret_inactive; 71 _earlyret_tos = ilgl; 72 _earlyret_value.j = 0L; 73 _earlyret_oop = NULL; 74 75 _jvmti_event_queue = NULL; 76 77 // add all the JvmtiEnvThreadState to the new JvmtiThreadState 78 { 79 JvmtiEnvIterator it; 80 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) { 81 if (env->is_valid()) { 82 add_env(env); 83 } 84 } 85 } 86 87 // link us into the list 88 { 89 // The thread state list manipulation code must not have safepoints. 90 // See periodic_clean_up(). 91 debug_only(NoSafepointVerifier nosafepoint;) 92 93 _prev = NULL; 94 _next = _head; 95 if (_head != NULL) { 96 _head->_prev = this; 97 } 98 _head = this; 99 } 100 101 // set this as the state for the thread 102 thread->set_jvmti_thread_state(this); 103 } 104 105 106 JvmtiThreadState::~JvmtiThreadState() { 107 assert(JvmtiThreadState_lock->is_locked(), "sanity check"); 108 109 // clear this as the state for the thread 110 get_thread()->set_jvmti_thread_state(NULL); 111 112 // zap our env thread states 113 { 114 JvmtiEnvBase::entering_dying_thread_env_iteration(); 115 JvmtiEnvThreadStateIterator it(this); 116 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ) { 117 JvmtiEnvThreadState* zap = ets; 118 ets = it.next(ets); 119 delete zap; 120 } 121 JvmtiEnvBase::leaving_dying_thread_env_iteration(); 122 } 123 124 // remove us from the list 125 { 126 // The thread state list manipulation code must not have safepoints. 127 // See periodic_clean_up(). 128 debug_only(NoSafepointVerifier nosafepoint;) 129 130 if (_prev == NULL) { 131 assert(_head == this, "sanity check"); 132 _head = _next; 133 } else { 134 assert(_head != this, "sanity check"); 135 _prev->_next = _next; 136 } 137 if (_next != NULL) { 138 _next->_prev = _prev; 139 } 140 _next = NULL; 141 _prev = NULL; 142 } 143 } 144 145 146 void 147 JvmtiThreadState::periodic_clean_up() { 148 assert(SafepointSynchronize::is_at_safepoint(), "at safepoint"); 149 150 // This iteration is initialized with "_head" instead of "JvmtiThreadState::first()" 151 // because the latter requires the JvmtiThreadState_lock. 152 // This iteration is safe at a safepoint as well, see the NoSafepointVerifier 153 // asserts at all list manipulation sites. 154 for (JvmtiThreadState *state = _head; state != NULL; state = state->next()) { 155 // For each environment thread state corresponding to an invalid environment 156 // unlink it from the list and deallocate it. 157 JvmtiEnvThreadStateIterator it(state); 158 JvmtiEnvThreadState* previous_ets = NULL; 159 JvmtiEnvThreadState* ets = it.first(); 160 while (ets != NULL) { 161 if (ets->get_env()->is_valid()) { 162 previous_ets = ets; 163 ets = it.next(ets); 164 } else { 165 // This one isn't valid, remove it from the list and deallocate it 166 JvmtiEnvThreadState* defunct_ets = ets; 167 ets = ets->next(); 168 if (previous_ets == NULL) { 169 assert(state->head_env_thread_state() == defunct_ets, "sanity check"); 170 state->set_head_env_thread_state(ets); 171 } else { 172 previous_ets->set_next(ets); 173 } 174 delete defunct_ets; 175 } 176 } 177 } 178 } 179 180 void JvmtiThreadState::add_env(JvmtiEnvBase *env) { 181 assert(JvmtiThreadState_lock->is_locked(), "sanity check"); 182 183 JvmtiEnvThreadState *new_ets = new JvmtiEnvThreadState(_thread, env); 184 // add this environment thread state to the end of the list (order is important) 185 { 186 // list deallocation (which occurs at a safepoint) cannot occur simultaneously 187 debug_only(NoSafepointVerifier nosafepoint;) 188 189 JvmtiEnvThreadStateIterator it(this); 190 JvmtiEnvThreadState* previous_ets = NULL; 191 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 192 previous_ets = ets; 193 } 194 if (previous_ets == NULL) { 195 set_head_env_thread_state(new_ets); 196 } else { 197 previous_ets->set_next(new_ets); 198 } 199 } 200 } 201 202 203 204 205 void JvmtiThreadState::enter_interp_only_mode() { 206 assert(_thread->get_interp_only_mode() == 0, "entering interp only when mode not zero"); 207 _thread->increment_interp_only_mode(); 208 } 209 210 211 void JvmtiThreadState::leave_interp_only_mode() { 212 assert(_thread->get_interp_only_mode() == 1, "leaving interp only when mode not one"); 213 _thread->decrement_interp_only_mode(); 214 } 215 216 217 // Helper routine used in several places 218 int JvmtiThreadState::count_frames() { 219 #ifdef ASSERT 220 Thread *current_thread = Thread::current(); 221 #endif 222 assert(current_thread == get_thread() || 223 SafepointSynchronize::is_at_safepoint() || 224 current_thread == get_thread()->active_handshaker(), 225 "call by myself / at safepoint / at handshake"); 226 227 if (!get_thread()->has_last_Java_frame()) return 0; // no Java frames 228 229 ResourceMark rm; 230 RegisterMap reg_map(get_thread()); 231 javaVFrame *jvf = get_thread()->last_java_vframe(®_map); 232 int n = 0; 233 while (jvf != NULL) { 234 Method* method = jvf->method(); 235 jvf = jvf->java_sender(); 236 n++; 237 } 238 return n; 239 } 240 241 242 void JvmtiThreadState::invalidate_cur_stack_depth() { 243 assert(SafepointSynchronize::is_at_safepoint() || 244 (JavaThread *)Thread::current() == get_thread() || 245 Thread::current() == get_thread()->active_handshaker(), 246 "bad synchronization with owner thread"); 247 248 _cur_stack_depth = UNKNOWN_STACK_DEPTH; 249 } 250 251 void JvmtiThreadState::incr_cur_stack_depth() { 252 guarantee(JavaThread::current() == get_thread(), "must be current thread"); 253 254 if (!is_interp_only_mode()) { 255 _cur_stack_depth = UNKNOWN_STACK_DEPTH; 256 } 257 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) { 258 ++_cur_stack_depth; 259 } 260 } 261 262 void JvmtiThreadState::decr_cur_stack_depth() { 263 guarantee(JavaThread::current() == get_thread(), "must be current thread"); 264 265 if (!is_interp_only_mode()) { 266 _cur_stack_depth = UNKNOWN_STACK_DEPTH; 267 } 268 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) { 269 --_cur_stack_depth; 270 assert(_cur_stack_depth >= 0, "incr/decr_cur_stack_depth mismatch"); 271 } 272 } 273 274 int JvmtiThreadState::cur_stack_depth() { 275 #ifdef ASSERT 276 Thread *current = Thread::current(); 277 #endif 278 guarantee(current == get_thread() || current == get_thread()->active_handshaker(), 279 "must be current thread or direct handshake"); 280 281 if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) { 282 _cur_stack_depth = count_frames(); 283 } else { 284 // heavy weight assert 285 assert(_cur_stack_depth == count_frames(), 286 "cur_stack_depth out of sync"); 287 } 288 return _cur_stack_depth; 289 } 290 291 bool JvmtiThreadState::may_be_walked() { 292 return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread())); 293 } 294 295 296 void JvmtiThreadState::process_pending_step_for_popframe() { 297 // We are single stepping as the last part of the PopFrame() dance 298 // so we have some house keeping to do. 299 300 JavaThread *thr = get_thread(); 301 if (thr->popframe_condition() != JavaThread::popframe_inactive) { 302 // If the popframe_condition field is not popframe_inactive, then 303 // we missed all of the popframe_field cleanup points: 304 // 305 // - unpack_frames() was not called (nothing to deopt) 306 // - remove_activation_preserving_args_entry() was not called 307 // (did not get suspended in a call_vm() family call and did 308 // not complete a call_vm() family call on the way here) 309 thr->clear_popframe_condition(); 310 } 311 312 // clearing the flag indicates we are done with the PopFrame() dance 313 clr_pending_step_for_popframe(); 314 315 // If exception was thrown in this frame, need to reset jvmti thread state. 316 // Single stepping may not get enabled correctly by the agent since 317 // exception state is passed in MethodExit event which may be sent at some 318 // time in the future. JDWP agent ignores MethodExit events if caused by 319 // an exception. 320 // 321 if (is_exception_detected()) { 322 clear_exception_state(); 323 } 324 // If step is pending for popframe then it may not be 325 // a repeat step. The new_bci and method_id is same as current_bci 326 // and current method_id after pop and step for recursive calls. 327 // Force the step by clearing the last location. 328 JvmtiEnvThreadStateIterator it(this); 329 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 330 ets->clear_current_location(); 331 } 332 } 333 334 335 // Class: JvmtiThreadState 336 // Function: update_for_pop_top_frame 337 // Description: 338 // This function removes any frame pop notification request for 339 // the top frame and invalidates both the current stack depth and 340 // all cached frameIDs. 341 // 342 // Called by: PopFrame 343 // 344 void JvmtiThreadState::update_for_pop_top_frame() { 345 if (is_interp_only_mode()) { 346 // remove any frame pop notification request for the top frame 347 // in any environment 348 int popframe_number = cur_stack_depth(); 349 { 350 JvmtiEnvThreadStateIterator it(this); 351 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 352 if (ets->is_frame_pop(popframe_number)) { 353 ets->clear_frame_pop(popframe_number); 354 } 355 } 356 } 357 // force stack depth to be recalculated 358 invalidate_cur_stack_depth(); 359 } else { 360 assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set"); 361 } 362 } 363 364 365 void JvmtiThreadState::process_pending_step_for_earlyret() { 366 // We are single stepping as the last part of the ForceEarlyReturn 367 // dance so we have some house keeping to do. 368 369 if (is_earlyret_pending()) { 370 // If the earlyret_state field is not earlyret_inactive, then 371 // we missed all of the earlyret_field cleanup points: 372 // 373 // - remove_activation() was not called 374 // (did not get suspended in a call_vm() family call and did 375 // not complete a call_vm() family call on the way here) 376 // 377 // One legitimate way for us to miss all the cleanup points is 378 // if we got here right after handling a compiled return. If that 379 // is the case, then we consider our return from compiled code to 380 // complete the ForceEarlyReturn request and we clear the condition. 381 clr_earlyret_pending(); 382 set_earlyret_oop(NULL); 383 clr_earlyret_value(); 384 } 385 386 // clearing the flag indicates we are done with 387 // the ForceEarlyReturn() dance 388 clr_pending_step_for_earlyret(); 389 390 // If exception was thrown in this frame, need to reset jvmti thread state. 391 // Single stepping may not get enabled correctly by the agent since 392 // exception state is passed in MethodExit event which may be sent at some 393 // time in the future. JDWP agent ignores MethodExit events if caused by 394 // an exception. 395 // 396 if (is_exception_detected()) { 397 clear_exception_state(); 398 } 399 // If step is pending for earlyret then it may not be a repeat step. 400 // The new_bci and method_id is same as current_bci and current 401 // method_id after earlyret and step for recursive calls. 402 // Force the step by clearing the last location. 403 JvmtiEnvThreadStateIterator it(this); 404 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 405 ets->clear_current_location(); 406 } 407 } 408 409 void JvmtiThreadState::oops_do(OopClosure* f, CodeBlobClosure* cf) { 410 f->do_oop((oop*) &_earlyret_oop); 411 412 // Keep nmethods from unloading on the event queue 413 if (_jvmti_event_queue != NULL) { 414 _jvmti_event_queue->oops_do(f, cf); 415 } 416 } 417 418 void JvmtiThreadState::nmethods_do(CodeBlobClosure* cf) { 419 // Keep nmethods from unloading on the event queue 420 if (_jvmti_event_queue != NULL) { 421 _jvmti_event_queue->nmethods_do(cf); 422 } 423 } 424 425 // Thread local event queue. 426 void JvmtiThreadState::enqueue_event(JvmtiDeferredEvent* event) { 427 if (_jvmti_event_queue == NULL) { 428 _jvmti_event_queue = new JvmtiDeferredEventQueue(); 429 } 430 // copy the event 431 _jvmti_event_queue->enqueue(*event); 432 } 433 434 void JvmtiThreadState::post_events(JvmtiEnv* env) { 435 if (_jvmti_event_queue != NULL) { 436 _jvmti_event_queue->post(env); // deletes each queue node 437 delete _jvmti_event_queue; 438 _jvmti_event_queue = NULL; 439 } 440 } 441 442 void JvmtiThreadState::run_nmethod_entry_barriers() { 443 if (_jvmti_event_queue != NULL) { 444 _jvmti_event_queue->run_nmethod_entry_barriers(); 445 } 446 }