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 Thread *current = Thread::current(); 276 guarantee(current == get_thread() || current == get_thread()->active_handshaker(), 277 "must be current thread or direct handshake"); 278 279 if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) { 280 _cur_stack_depth = count_frames(); 281 } else { 282 // heavy weight assert 283 assert(_cur_stack_depth == count_frames(), 284 "cur_stack_depth out of sync"); 285 } 286 return _cur_stack_depth; 287 } 288 289 bool JvmtiThreadState::may_be_walked() { 290 return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread())); 291 } 292 293 294 void JvmtiThreadState::process_pending_step_for_popframe() { 295 // We are single stepping as the last part of the PopFrame() dance 296 // so we have some house keeping to do. 297 298 JavaThread *thr = get_thread(); 299 if (thr->popframe_condition() != JavaThread::popframe_inactive) { 300 // If the popframe_condition field is not popframe_inactive, then 301 // we missed all of the popframe_field cleanup points: 302 // 303 // - unpack_frames() was not called (nothing to deopt) 304 // - remove_activation_preserving_args_entry() was not called 305 // (did not get suspended in a call_vm() family call and did 306 // not complete a call_vm() family call on the way here) 307 thr->clear_popframe_condition(); 308 } 309 310 // clearing the flag indicates we are done with the PopFrame() dance 311 clr_pending_step_for_popframe(); 312 313 // If exception was thrown in this frame, need to reset jvmti thread state. 314 // Single stepping may not get enabled correctly by the agent since 315 // exception state is passed in MethodExit event which may be sent at some 316 // time in the future. JDWP agent ignores MethodExit events if caused by 317 // an exception. 318 // 319 if (is_exception_detected()) { 320 clear_exception_state(); 321 } 322 // If step is pending for popframe then it may not be 323 // a repeat step. The new_bci and method_id is same as current_bci 324 // and current method_id after pop and step for recursive calls. 325 // Force the step by clearing the last location. 326 JvmtiEnvThreadStateIterator it(this); 327 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 328 ets->clear_current_location(); 329 } 330 } 331 332 333 // Class: JvmtiThreadState 334 // Function: update_for_pop_top_frame 335 // Description: 336 // This function removes any frame pop notification request for 337 // the top frame and invalidates both the current stack depth and 338 // all cached frameIDs. 339 // 340 // Called by: PopFrame 341 // 342 void JvmtiThreadState::update_for_pop_top_frame() { 343 if (is_interp_only_mode()) { 344 // remove any frame pop notification request for the top frame 345 // in any environment 346 int popframe_number = cur_stack_depth(); 347 { 348 JvmtiEnvThreadStateIterator it(this); 349 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 350 if (ets->is_frame_pop(popframe_number)) { 351 ets->clear_frame_pop(popframe_number); 352 } 353 } 354 } 355 // force stack depth to be recalculated 356 invalidate_cur_stack_depth(); 357 } else { 358 assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set"); 359 } 360 } 361 362 363 void JvmtiThreadState::process_pending_step_for_earlyret() { 364 // We are single stepping as the last part of the ForceEarlyReturn 365 // dance so we have some house keeping to do. 366 367 if (is_earlyret_pending()) { 368 // If the earlyret_state field is not earlyret_inactive, then 369 // we missed all of the earlyret_field cleanup points: 370 // 371 // - remove_activation() was not called 372 // (did not get suspended in a call_vm() family call and did 373 // not complete a call_vm() family call on the way here) 374 // 375 // One legitimate way for us to miss all the cleanup points is 376 // if we got here right after handling a compiled return. If that 377 // is the case, then we consider our return from compiled code to 378 // complete the ForceEarlyReturn request and we clear the condition. 379 clr_earlyret_pending(); 380 set_earlyret_oop(NULL); 381 clr_earlyret_value(); 382 } 383 384 // clearing the flag indicates we are done with 385 // the ForceEarlyReturn() dance 386 clr_pending_step_for_earlyret(); 387 388 // If exception was thrown in this frame, need to reset jvmti thread state. 389 // Single stepping may not get enabled correctly by the agent since 390 // exception state is passed in MethodExit event which may be sent at some 391 // time in the future. JDWP agent ignores MethodExit events if caused by 392 // an exception. 393 // 394 if (is_exception_detected()) { 395 clear_exception_state(); 396 } 397 // If step is pending for earlyret then it may not be a repeat step. 398 // The new_bci and method_id is same as current_bci and current 399 // method_id after earlyret and step for recursive calls. 400 // Force the step by clearing the last location. 401 JvmtiEnvThreadStateIterator it(this); 402 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) { 403 ets->clear_current_location(); 404 } 405 } 406 407 void JvmtiThreadState::oops_do(OopClosure* f, CodeBlobClosure* cf) { 408 f->do_oop((oop*) &_earlyret_oop); 409 410 // Keep nmethods from unloading on the event queue 411 if (_jvmti_event_queue != NULL) { 412 _jvmti_event_queue->oops_do(f, cf); 413 } 414 } 415 416 void JvmtiThreadState::nmethods_do(CodeBlobClosure* cf) { 417 // Keep nmethods from unloading on the event queue 418 if (_jvmti_event_queue != NULL) { 419 _jvmti_event_queue->nmethods_do(cf); 420 } 421 } 422 423 // Thread local event queue. 424 void JvmtiThreadState::enqueue_event(JvmtiDeferredEvent* event) { 425 if (_jvmti_event_queue == NULL) { 426 _jvmti_event_queue = new JvmtiDeferredEventQueue(); 427 } 428 // copy the event 429 _jvmti_event_queue->enqueue(*event); 430 } 431 432 void JvmtiThreadState::post_events(JvmtiEnv* env) { 433 if (_jvmti_event_queue != NULL) { 434 _jvmti_event_queue->post(env); // deletes each queue node 435 delete _jvmti_event_queue; 436 _jvmti_event_queue = NULL; 437 } 438 } 439 440 void JvmtiThreadState::run_nmethod_entry_barriers() { 441 if (_jvmti_event_queue != NULL) { 442 _jvmti_event_queue->run_nmethod_entry_barriers(); 443 } 444 }