1 /* 2 * Copyright (c) 2003, 2017, 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/systemDictionary.hpp" 27 #include "interpreter/interpreter.hpp" 28 #include "jvmtifiles/jvmtiEnv.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "prims/jvmtiEnvThreadState.hpp" 31 #include "prims/jvmtiEventController.inline.hpp" 32 #include "prims/jvmtiImpl.hpp" 33 #include "runtime/handles.hpp" 34 #include "runtime/handles.inline.hpp" 35 #include "runtime/interfaceSupport.inline.hpp" 36 #include "runtime/javaCalls.hpp" 37 #include "runtime/signature.hpp" 38 #include "runtime/thread.inline.hpp" 39 #include "runtime/vframe.hpp" 40 #include "runtime/vmOperations.hpp" 41 42 43 /////////////////////////////////////////////////////////////// 44 // 45 // class JvmtiFramePop 46 // 47 48 #ifndef PRODUCT 49 void JvmtiFramePop::print() { 50 tty->print_cr("_frame_number=%d", _frame_number); 51 } 52 #endif 53 54 55 /////////////////////////////////////////////////////////////// 56 // 57 // class JvmtiFramePops - private methods 58 // 59 60 void 61 JvmtiFramePops::set(JvmtiFramePop& fp) { 62 if (_pops->find(fp.frame_number()) < 0) { 63 _pops->append(fp.frame_number()); 64 } 65 } 66 67 68 void 69 JvmtiFramePops::clear(JvmtiFramePop& fp) { 70 assert(_pops->length() > 0, "No more frame pops"); 71 72 _pops->remove(fp.frame_number()); 73 } 74 75 76 int 77 JvmtiFramePops::clear_to(JvmtiFramePop& fp) { 78 int cleared = 0; 79 int index = 0; 80 while (index < _pops->length()) { 81 JvmtiFramePop pop = JvmtiFramePop(_pops->at(index)); 82 if (pop.above_on_stack(fp)) { 83 _pops->remove_at(index); 84 ++cleared; 85 } else { 86 ++index; 87 } 88 } 89 return cleared; 90 } 91 92 93 /////////////////////////////////////////////////////////////// 94 // 95 // class JvmtiFramePops - public methods 96 // 97 98 JvmtiFramePops::JvmtiFramePops() { 99 _pops = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int> (2, true); 100 } 101 102 JvmtiFramePops::~JvmtiFramePops() { 103 // return memory to c_heap. 104 delete _pops; 105 } 106 107 108 #ifndef PRODUCT 109 void JvmtiFramePops::print() { 110 ResourceMark rm; 111 112 int n = _pops->length(); 113 for (int i=0; i<n; i++) { 114 JvmtiFramePop fp = JvmtiFramePop(_pops->at(i)); 115 tty->print("%d: ", i); 116 fp.print(); 117 tty->cr(); 118 } 119 } 120 #endif 121 122 /////////////////////////////////////////////////////////////// 123 // 124 // class JvmtiEnvThreadState 125 // 126 // Instances of JvmtiEnvThreadState hang off of each JvmtiThreadState, 127 // one per JvmtiEnv. 128 // 129 130 JvmtiEnvThreadState::JvmtiEnvThreadState(JavaThread *thread, JvmtiEnvBase *env) : 131 _event_enable() { 132 _thread = thread; 133 _env = (JvmtiEnv*)env; 134 _next = NULL; 135 _frame_pops = NULL; 136 _current_bci = 0; 137 _current_method_id = NULL; 138 _breakpoint_posted = false; 139 _single_stepping_posted = false; 140 _agent_thread_local_storage_data = NULL; 141 } 142 143 JvmtiEnvThreadState::~JvmtiEnvThreadState() { 144 delete _frame_pops; 145 _frame_pops = NULL; 146 } 147 148 // Given that a new (potential) event has come in, 149 // maintain the current JVMTI location on a per-thread per-env basis 150 // and use it to filter out duplicate events: 151 // - instruction rewrites 152 // - breakpoint followed by single step 153 // - single step at a breakpoint 154 void JvmtiEnvThreadState::compare_and_set_current_location(Method* new_method, 155 address new_location, jvmtiEvent event) { 156 157 int new_bci = new_location - new_method->code_base(); 158 159 // The method is identified and stored as a jmethodID which is safe in this 160 // case because the class cannot be unloaded while a method is executing. 161 jmethodID new_method_id = new_method->jmethod_id(); 162 163 // the last breakpoint or single step was at this same location 164 if (_current_bci == new_bci && _current_method_id == new_method_id) { 165 switch (event) { 166 case JVMTI_EVENT_BREAKPOINT: 167 // Repeat breakpoint is complicated. If we previously posted a breakpoint 168 // event at this location and if we also single stepped at this location 169 // then we skip the duplicate breakpoint. 170 _breakpoint_posted = _breakpoint_posted && _single_stepping_posted; 171 break; 172 case JVMTI_EVENT_SINGLE_STEP: 173 // Repeat single step is easy: just don't post it again. 174 // If step is pending for popframe then it may not be 175 // a repeat step. The new_bci and method_id is same as current_bci 176 // and current method_id after pop and step for recursive calls. 177 // This has been handled by clearing the location 178 _single_stepping_posted = true; 179 break; 180 default: 181 assert(false, "invalid event value passed"); 182 break; 183 } 184 return; 185 } 186 187 set_current_location(new_method_id, new_bci); 188 _breakpoint_posted = false; 189 _single_stepping_posted = false; 190 } 191 192 193 JvmtiFramePops* JvmtiEnvThreadState::get_frame_pops() { 194 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 195 "frame pop data only accessible from same thread or at safepoint"); 196 if (_frame_pops == NULL) { 197 _frame_pops = new JvmtiFramePops(); 198 assert(_frame_pops != NULL, "_frame_pops != NULL"); 199 } 200 return _frame_pops; 201 } 202 203 204 bool JvmtiEnvThreadState::has_frame_pops() { 205 return _frame_pops == NULL? false : (_frame_pops->length() > 0); 206 } 207 208 void JvmtiEnvThreadState::set_frame_pop(int frame_number) { 209 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 210 "frame pop data only accessible from same thread or at safepoint"); 211 JvmtiFramePop fpop(frame_number); 212 JvmtiEventController::set_frame_pop(this, fpop); 213 } 214 215 216 void JvmtiEnvThreadState::clear_frame_pop(int frame_number) { 217 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 218 "frame pop data only accessible from same thread or at safepoint"); 219 JvmtiFramePop fpop(frame_number); 220 JvmtiEventController::clear_frame_pop(this, fpop); 221 } 222 223 224 void JvmtiEnvThreadState::clear_to_frame_pop(int frame_number) { 225 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 226 "frame pop data only accessible from same thread or at safepoint"); 227 JvmtiFramePop fpop(frame_number); 228 JvmtiEventController::clear_to_frame_pop(this, fpop); 229 } 230 231 232 bool JvmtiEnvThreadState::is_frame_pop(int cur_frame_number) { 233 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 234 "frame pop data only accessible from same thread or at safepoint"); 235 if (!get_thread()->is_interp_only_mode() || _frame_pops == NULL) { 236 return false; 237 } 238 JvmtiFramePop fp(cur_frame_number); 239 return get_frame_pops()->contains(fp); 240 } 241 242 243 class VM_GetCurrentLocation : public VM_Operation { 244 private: 245 JavaThread *_thread; 246 jmethodID _method_id; 247 int _bci; 248 249 public: 250 VM_GetCurrentLocation(JavaThread *thread) { 251 _thread = thread; 252 } 253 VMOp_Type type() const { return VMOp_GetCurrentLocation; } 254 void doit() { 255 ResourceMark rmark; // _thread != Thread::current() 256 RegisterMap rm(_thread, false); 257 // There can be a race condition between a VM_Operation reaching a safepoint 258 // and the target thread exiting from Java execution. 259 // We must recheck the last Java frame still exists. 260 if (!_thread->is_exiting() && _thread->has_last_Java_frame()) { 261 javaVFrame* vf = _thread->last_java_vframe(&rm); 262 assert(vf != NULL, "must have last java frame"); 263 Method* method = vf->method(); 264 _method_id = method->jmethod_id(); 265 _bci = vf->bci(); 266 } else { 267 // Clear current location as the target thread has no Java frames anymore. 268 _method_id = (jmethodID)NULL; 269 _bci = 0; 270 } 271 } 272 void get_current_location(jmethodID *method_id, int *bci) { 273 *method_id = _method_id; 274 *bci = _bci; 275 } 276 }; 277 278 void JvmtiEnvThreadState::reset_current_location(jvmtiEvent event_type, bool enabled) { 279 assert(event_type == JVMTI_EVENT_SINGLE_STEP || event_type == JVMTI_EVENT_BREAKPOINT, 280 "must be single-step or breakpoint event"); 281 282 // Current location is used to detect the following: 283 // 1) a breakpoint event followed by single-stepping to the same bci 284 // 2) single-step to a bytecode that will be transformed to a fast version 285 // We skip to avoid posting the duplicate single-stepping event. 286 287 // If single-stepping is disabled, clear current location so that 288 // single-stepping to the same method and bcp at a later time will be 289 // detected if single-stepping is enabled at that time (see 4388912). 290 291 // If single-stepping is enabled, set the current location to the 292 // current method and bcp. This covers the following type of case, 293 // e.g., the debugger stepi command: 294 // - bytecode single stepped 295 // - SINGLE_STEP event posted and SINGLE_STEP event disabled 296 // - SINGLE_STEP event reenabled 297 // - bytecode rewritten to fast version 298 299 // If breakpoint event is disabled, clear current location only if 300 // single-stepping is not enabled. Otherwise, keep the thread location 301 // to detect any duplicate events. 302 303 if (enabled) { 304 // If enabling breakpoint, no need to reset. 305 // Can't do anything if empty stack. 306 if (event_type == JVMTI_EVENT_SINGLE_STEP && _thread->has_last_Java_frame()) { 307 jmethodID method_id; 308 int bci; 309 // The java thread stack may not be walkable for a running thread 310 // so get current location at safepoint. 311 VM_GetCurrentLocation op(_thread); 312 VMThread::execute(&op); 313 op.get_current_location(&method_id, &bci); 314 set_current_location(method_id, bci); 315 } 316 } else if (event_type == JVMTI_EVENT_SINGLE_STEP || !is_enabled(JVMTI_EVENT_SINGLE_STEP)) { 317 // If this is to disable breakpoint, also check if single-step is not enabled 318 clear_current_location(); 319 } 320 }