1 /* 2 * Copyright (c) 2003, 2014, 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.hpp" 36 #include "runtime/javaCalls.hpp" 37 #include "runtime/signature.hpp" 38 #include "runtime/vframe.hpp" 39 #include "runtime/vm_operations.hpp" 40 41 42 /////////////////////////////////////////////////////////////// 43 // 44 // class JvmtiFramePop 45 // 46 47 #ifndef PRODUCT 48 void JvmtiFramePop::print() { 49 tty->print_cr("_frame_number=%d", _frame_number); 50 } 51 #endif 52 53 54 /////////////////////////////////////////////////////////////// 55 // 56 // class JvmtiFramePops - private methods 57 // 58 59 void 60 JvmtiFramePops::set(JvmtiFramePop& fp) { 61 if (_pops->find(fp.frame_number()) < 0) { 62 _pops->append(fp.frame_number()); 63 } 64 } 65 66 67 void 68 JvmtiFramePops::clear(JvmtiFramePop& fp) { 69 assert(_pops->length() > 0, "No more frame pops"); 70 71 _pops->remove(fp.frame_number()); 72 } 73 74 75 int 76 JvmtiFramePops::clear_to(JvmtiFramePop& fp) { 77 int cleared = 0; 78 int index = 0; 79 while (index < _pops->length()) { 80 JvmtiFramePop pop = JvmtiFramePop(_pops->at(index)); 81 if (pop.above_on_stack(fp)) { 82 _pops->remove_at(index); 83 ++cleared; 84 } else { 85 ++index; 86 } 87 } 88 return cleared; 89 } 90 91 92 /////////////////////////////////////////////////////////////// 93 // 94 // class JvmtiFramePops - public methods 95 // 96 97 JvmtiFramePops::JvmtiFramePops() { 98 _pops = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<int> (2, true); 99 } 100 101 JvmtiFramePops::~JvmtiFramePops() { 102 // return memory to c_heap. 103 delete _pops; 104 } 105 106 107 #ifndef PRODUCT 108 void JvmtiFramePops::print() { 109 ResourceMark rm; 110 111 int n = _pops->length(); 112 for (int i=0; i<n; i++) { 113 JvmtiFramePop fp = JvmtiFramePop(_pops->at(i)); 114 tty->print("%d: ", i); 115 fp.print(); 116 tty->cr(); 117 } 118 } 119 #endif 120 121 /////////////////////////////////////////////////////////////// 122 // 123 // class JvmtiEnvThreadState 124 // 125 // Instances of JvmtiEnvThreadState hang off of each JvmtiThreadState, 126 // one per JvmtiEnv. 127 // 128 129 JvmtiEnvThreadState::JvmtiEnvThreadState(JavaThread *thread, JvmtiEnvBase *env) : 130 _event_enable() { 131 _thread = thread; 132 _env = (JvmtiEnv*)env; 133 _next = NULL; 134 _frame_pops = NULL; 135 _current_bci = 0; 136 _current_method_id = NULL; 137 _breakpoint_posted = false; 138 _single_stepping_posted = false; 139 _agent_thread_local_storage_data = NULL; 140 } 141 142 JvmtiEnvThreadState::~JvmtiEnvThreadState() { 143 delete _frame_pops; 144 _frame_pops = NULL; 145 } 146 147 // Given that a new (potential) event has come in, 148 // maintain the current JVMTI location on a per-thread per-env basis 149 // and use it to filter out duplicate events: 150 // - instruction rewrites 151 // - breakpoint followed by single step 152 // - single step at a breakpoint 153 void JvmtiEnvThreadState::compare_and_set_current_location(Method* new_method, 154 address new_location, jvmtiEvent event) { 155 156 int new_bci = new_location - new_method->code_base(); 157 158 // The method is identified and stored as a jmethodID which is safe in this 159 // case because the class cannot be unloaded while a method is executing. 160 jmethodID new_method_id = new_method->jmethod_id(); 161 162 // the last breakpoint or single step was at this same location 163 if (_current_bci == new_bci && _current_method_id == new_method_id) { 164 switch (event) { 165 case JVMTI_EVENT_BREAKPOINT: 166 // Repeat breakpoint is complicated. If we previously posted a breakpoint 167 // event at this location and if we also single stepped at this location 168 // then we skip the duplicate breakpoint. 169 _breakpoint_posted = _breakpoint_posted && _single_stepping_posted; 170 break; 171 case JVMTI_EVENT_SINGLE_STEP: 172 // Repeat single step is easy: just don't post it again. 173 // If step is pending for popframe then it may not be 174 // a repeat step. The new_bci and method_id is same as current_bci 175 // and current method_id after pop and step for recursive calls. 176 // This has been handled by clearing the location 177 _single_stepping_posted = true; 178 break; 179 default: 180 assert(false, "invalid event value passed"); 181 break; 182 } 183 return; 184 } 185 186 set_current_location(new_method_id, new_bci); 187 _breakpoint_posted = false; 188 _single_stepping_posted = false; 189 } 190 191 192 JvmtiFramePops* JvmtiEnvThreadState::get_frame_pops() { 193 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 194 "frame pop data only accessible from same thread or at safepoint"); 195 if (_frame_pops == NULL) { 196 _frame_pops = new JvmtiFramePops(); 197 assert(_frame_pops != NULL, "_frame_pops != NULL"); 198 } 199 return _frame_pops; 200 } 201 202 203 bool JvmtiEnvThreadState::has_frame_pops() { 204 return _frame_pops == NULL? false : (_frame_pops->length() > 0); 205 } 206 207 void JvmtiEnvThreadState::set_frame_pop(int frame_number) { 208 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 209 "frame pop data only accessible from same thread or at safepoint"); 210 JvmtiFramePop fpop(frame_number); 211 JvmtiEventController::set_frame_pop(this, fpop); 212 } 213 214 215 void JvmtiEnvThreadState::clear_frame_pop(int frame_number) { 216 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 217 "frame pop data only accessible from same thread or at safepoint"); 218 JvmtiFramePop fpop(frame_number); 219 JvmtiEventController::clear_frame_pop(this, fpop); 220 } 221 222 223 void JvmtiEnvThreadState::clear_to_frame_pop(int frame_number) { 224 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 225 "frame pop data only accessible from same thread or at safepoint"); 226 JvmtiFramePop fpop(frame_number); 227 JvmtiEventController::clear_to_frame_pop(this, fpop); 228 } 229 230 231 bool JvmtiEnvThreadState::is_frame_pop(int cur_frame_number) { 232 assert(get_thread() == Thread::current() || SafepointSynchronize::is_at_safepoint(), 233 "frame pop data only accessible from same thread or at safepoint"); 234 if (!get_thread()->is_interp_only_mode() || _frame_pops == NULL) { 235 return false; 236 } 237 JvmtiFramePop fp(cur_frame_number); 238 return get_frame_pops()->contains(fp); 239 } 240 241 242 class VM_GetCurrentLocation : public VM_Operation { 243 private: 244 JavaThread *_thread; 245 jmethodID _method_id; 246 int _bci; 247 248 public: 249 VM_GetCurrentLocation(JavaThread *thread) { 250 _thread = thread; 251 } 252 VMOp_Type type() const { return VMOp_GetCurrentLocation; } 253 void doit() { 254 ResourceMark rmark; // _thread != Thread::current() 255 RegisterMap rm(_thread, false); 256 // There can be a race condition between a VM_Operation reaching a safepoint 257 // and the target thread exiting from Java execution. 258 // We must recheck the last Java frame still exists. 259 if (!_thread->is_exiting() && _thread->has_last_Java_frame()) { 260 javaVFrame* vf = _thread->last_java_vframe(&rm); 261 assert(vf != NULL, "must have last java frame"); 262 Method* method = vf->method(); 263 _method_id = method->jmethod_id(); 264 _bci = vf->bci(); 265 } else { 266 // Clear current location as the target thread has no Java frames anymore. 267 _method_id = (jmethodID)NULL; 268 _bci = 0; 269 } 270 } 271 void get_current_location(jmethodID *method_id, int *bci) { 272 *method_id = _method_id; 273 *bci = _bci; 274 } 275 }; 276 277 void JvmtiEnvThreadState::reset_current_location(jvmtiEvent event_type, bool enabled) { 278 assert(event_type == JVMTI_EVENT_SINGLE_STEP || event_type == JVMTI_EVENT_BREAKPOINT, 279 "must be single-step or breakpoint event"); 280 281 // Current location is used to detect the following: 282 // 1) a breakpoint event followed by single-stepping to the same bci 283 // 2) single-step to a bytecode that will be transformed to a fast version 284 // We skip to avoid posting the duplicate single-stepping event. 285 286 // If single-stepping is disabled, clear current location so that 287 // single-stepping to the same method and bcp at a later time will be 288 // detected if single-stepping is enabled at that time (see 4388912). 289 290 // If single-stepping is enabled, set the current location to the 291 // current method and bcp. This covers the following type of case, 292 // e.g., the debugger stepi command: 293 // - bytecode single stepped 294 // - SINGLE_STEP event posted and SINGLE_STEP event disabled 295 // - SINGLE_STEP event reenabled 296 // - bytecode rewritten to fast version 297 298 // If breakpoint event is disabled, clear current location only if 299 // single-stepping is not enabled. Otherwise, keep the thread location 300 // to detect any duplicate events. 301 302 if (enabled) { 303 // If enabling breakpoint, no need to reset. 304 // Can't do anything if empty stack. 305 if (event_type == JVMTI_EVENT_SINGLE_STEP && _thread->has_last_Java_frame()) { 306 jmethodID method_id; 307 int bci; 308 // The java thread stack may not be walkable for a running thread 309 // so get current location at safepoint. 310 VM_GetCurrentLocation op(_thread); 311 VMThread::execute(&op); 312 op.get_current_location(&method_id, &bci); 313 set_current_location(method_id, bci); 314 } 315 } else if (event_type == JVMTI_EVENT_SINGLE_STEP || !is_enabled(JVMTI_EVENT_SINGLE_STEP)) { 316 // If this is to disable breakpoint, also check if single-step is not enabled 317 clear_current_location(); 318 } 319 }