1 /*
2 * Copyright (c) 2003, 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 "gc/shared/gcLocker.hpp"
27 #include "jvmtifiles/jvmtiEnv.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "prims/jvmtiEventController.inline.hpp"
30 #include "prims/jvmtiImpl.hpp"
31 #include "prims/jvmtiThreadState.inline.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 // add all the JvmtiEnvThreadState to the new JvmtiThreadState
76 {
77 JvmtiEnvIterator it;
78 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
79 if (env->is_valid()) {
80 add_env(env);
81 }
82 }
83 }
84
85 // link us into the list
86 {
87 // The thread state list manipulation code must not have safepoints.
88 // See periodic_clean_up().
89 debug_only(NoSafepointVerifier nosafepoint;)
90
91 _prev = NULL;
92 _next = _head;
93 if (_head != NULL) {
94 _head->_prev = this;
95 }
96 _head = this;
97 }
98
99 // set this as the state for the thread
100 thread->set_jvmti_thread_state(this);
101 }
102
103
104 JvmtiThreadState::~JvmtiThreadState() {
105 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
106
107 // clear this as the state for the thread
108 get_thread()->set_jvmti_thread_state(NULL);
109
110 // zap our env thread states
111 {
112 JvmtiEnvBase::entering_dying_thread_env_iteration();
113 JvmtiEnvThreadStateIterator it(this);
114 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ) {
115 JvmtiEnvThreadState* zap = ets;
116 ets = it.next(ets);
117 delete zap;
118 }
119 JvmtiEnvBase::leaving_dying_thread_env_iteration();
120 }
121
122 // remove us from the list
123 {
124 // The thread state list manipulation code must not have safepoints.
125 // See periodic_clean_up().
126 debug_only(NoSafepointVerifier nosafepoint;)
127
128 if (_prev == NULL) {
129 assert(_head == this, "sanity check");
130 _head = _next;
131 } else {
132 assert(_head != this, "sanity check");
133 _prev->_next = _next;
134 }
135 if (_next != NULL) {
136 _next->_prev = _prev;
137 }
138 _next = NULL;
139 _prev = NULL;
140 }
141 }
142
143
144 void
145 JvmtiThreadState::periodic_clean_up() {
146 assert(SafepointSynchronize::is_at_safepoint(), "at safepoint");
147
148 // This iteration is initialized with "_head" instead of "JvmtiThreadState::first()"
149 // because the latter requires the JvmtiThreadState_lock.
150 // This iteration is safe at a safepoint as well, see the NoSafepointVerifier
151 // asserts at all list manipulation sites.
152 for (JvmtiThreadState *state = _head; state != NULL; state = state->next()) {
153 // For each environment thread state corresponding to an invalid environment
154 // unlink it from the list and deallocate it.
155 JvmtiEnvThreadStateIterator it(state);
156 JvmtiEnvThreadState* previous_ets = NULL;
157 JvmtiEnvThreadState* ets = it.first();
158 while (ets != NULL) {
159 if (ets->get_env()->is_valid()) {
160 previous_ets = ets;
161 ets = it.next(ets);
162 } else {
163 // This one isn't valid, remove it from the list and deallocate it
164 JvmtiEnvThreadState* defunct_ets = ets;
165 ets = ets->next();
166 if (previous_ets == NULL) {
167 assert(state->head_env_thread_state() == defunct_ets, "sanity check");
168 state->set_head_env_thread_state(ets);
169 } else {
170 previous_ets->set_next(ets);
171 }
172 delete defunct_ets;
173 }
174 }
175 }
176 }
177
178 void JvmtiThreadState::add_env(JvmtiEnvBase *env) {
179 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
180
181 JvmtiEnvThreadState *new_ets = new JvmtiEnvThreadState(_thread, env);
182 // add this environment thread state to the end of the list (order is important)
183 {
184 // list deallocation (which occurs at a safepoint) cannot occur simultaneously
185 debug_only(NoSafepointVerifier nosafepoint;)
186
187 JvmtiEnvThreadStateIterator it(this);
188 JvmtiEnvThreadState* previous_ets = NULL;
189 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
190 previous_ets = ets;
191 }
192 if (previous_ets == NULL) {
193 set_head_env_thread_state(new_ets);
194 } else {
195 previous_ets->set_next(new_ets);
196 }
197 }
198 }
199
200
201
202
203 void JvmtiThreadState::enter_interp_only_mode() {
204 assert(_thread->get_interp_only_mode() == 0, "entering interp only when mode not zero");
205 _thread->increment_interp_only_mode();
206 }
207
208
209 void JvmtiThreadState::leave_interp_only_mode() {
210 assert(_thread->get_interp_only_mode() == 1, "leaving interp only when mode not one");
211 _thread->decrement_interp_only_mode();
212 }
213
214
215 // Helper routine used in several places
216 int JvmtiThreadState::count_frames() {
217 guarantee(SafepointSynchronize::is_at_safepoint() ||
218 (JavaThread *)Thread::current() == get_thread(),
219 "must be current thread or at safepoint");
220
221 if (!get_thread()->has_last_Java_frame()) return 0; // no Java frames
222
223 ResourceMark rm;
224 RegisterMap reg_map(get_thread());
225 javaVFrame *jvf = get_thread()->last_java_vframe(®_map);
226 int n = 0;
227 while (jvf != NULL) {
228 Method* method = jvf->method();
229 jvf = jvf->java_sender();
230 n++;
231 }
232 return n;
233 }
234
235
236 void JvmtiThreadState::invalidate_cur_stack_depth() {
237 guarantee(SafepointSynchronize::is_at_safepoint() ||
238 (JavaThread *)Thread::current() == get_thread(),
239 "must be current thread or at safepoint");
240
241 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
242 }
243
244 void JvmtiThreadState::incr_cur_stack_depth() {
245 guarantee(JavaThread::current() == get_thread(), "must be current thread");
246
247 if (!is_interp_only_mode()) {
248 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
249 }
250 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
251 ++_cur_stack_depth;
252 }
253 }
254
255 void JvmtiThreadState::decr_cur_stack_depth() {
256 guarantee(JavaThread::current() == get_thread(), "must be current thread");
257
258 if (!is_interp_only_mode()) {
259 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
260 }
261 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
262 --_cur_stack_depth;
263 assert(_cur_stack_depth >= 0, "incr/decr_cur_stack_depth mismatch");
264 }
265 }
266
267 int JvmtiThreadState::cur_stack_depth() {
268 guarantee(SafepointSynchronize::is_at_safepoint() ||
269 (JavaThread *)Thread::current() == get_thread(),
270 "must be current thread or at safepoint");
271
272 if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) {
273 _cur_stack_depth = count_frames();
274 } else {
275 // heavy weight assert
276 assert(_cur_stack_depth == count_frames(),
277 "cur_stack_depth out of sync");
278 }
279 return _cur_stack_depth;
280 }
281
282 bool JvmtiThreadState::may_be_walked() {
283 return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread()));
284 }
285
286
287 void JvmtiThreadState::process_pending_step_for_popframe() {
288 // We are single stepping as the last part of the PopFrame() dance
289 // so we have some house keeping to do.
290
291 JavaThread *thr = get_thread();
292 if (thr->popframe_condition() != JavaThread::popframe_inactive) {
293 // If the popframe_condition field is not popframe_inactive, then
294 // we missed all of the popframe_field cleanup points:
295 //
296 // - unpack_frames() was not called (nothing to deopt)
297 // - remove_activation_preserving_args_entry() was not called
298 // (did not get suspended in a call_vm() family call and did
299 // not complete a call_vm() family call on the way here)
300 thr->clear_popframe_condition();
301 }
302
303 // clearing the flag indicates we are done with the PopFrame() dance
304 clr_pending_step_for_popframe();
305
306 // If exception was thrown in this frame, need to reset jvmti thread state.
307 // Single stepping may not get enabled correctly by the agent since
308 // exception state is passed in MethodExit event which may be sent at some
309 // time in the future. JDWP agent ignores MethodExit events if caused by
310 // an exception.
311 //
312 if (is_exception_detected()) {
313 clear_exception_state();
314 }
315 // If step is pending for popframe then it may not be
316 // a repeat step. The new_bci and method_id is same as current_bci
317 // and current method_id after pop and step for recursive calls.
318 // Force the step by clearing the last location.
319 JvmtiEnvThreadStateIterator it(this);
320 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
321 ets->clear_current_location();
322 }
323 }
324
325
326 // Class: JvmtiThreadState
327 // Function: update_for_pop_top_frame
328 // Description:
329 // This function removes any frame pop notification request for
330 // the top frame and invalidates both the current stack depth and
331 // all cached frameIDs.
332 //
333 // Called by: PopFrame
334 //
335 void JvmtiThreadState::update_for_pop_top_frame() {
336 if (is_interp_only_mode()) {
337 // remove any frame pop notification request for the top frame
338 // in any environment
339 int popframe_number = cur_stack_depth();
340 {
341 JvmtiEnvThreadStateIterator it(this);
342 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
343 if (ets->is_frame_pop(popframe_number)) {
344 ets->clear_frame_pop(popframe_number);
345 }
346 }
347 }
348 // force stack depth to be recalculated
349 invalidate_cur_stack_depth();
350 } else {
351 assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set");
352 }
353 }
354
355
356 void JvmtiThreadState::process_pending_step_for_earlyret() {
357 // We are single stepping as the last part of the ForceEarlyReturn
358 // dance so we have some house keeping to do.
359
360 if (is_earlyret_pending()) {
361 // If the earlyret_state field is not earlyret_inactive, then
362 // we missed all of the earlyret_field cleanup points:
363 //
364 // - remove_activation() was not called
365 // (did not get suspended in a call_vm() family call and did
366 // not complete a call_vm() family call on the way here)
367 //
368 // One legitimate way for us to miss all the cleanup points is
369 // if we got here right after handling a compiled return. If that
370 // is the case, then we consider our return from compiled code to
371 // complete the ForceEarlyReturn request and we clear the condition.
372 clr_earlyret_pending();
373 set_earlyret_oop(NULL);
374 clr_earlyret_value();
375 }
376
377 // clearing the flag indicates we are done with
378 // the ForceEarlyReturn() dance
379 clr_pending_step_for_earlyret();
380
381 // If exception was thrown in this frame, need to reset jvmti thread state.
382 // Single stepping may not get enabled correctly by the agent since
383 // exception state is passed in MethodExit event which may be sent at some
384 // time in the future. JDWP agent ignores MethodExit events if caused by
385 // an exception.
386 //
387 if (is_exception_detected()) {
388 clear_exception_state();
389 }
390 // If step is pending for earlyret then it may not be a repeat step.
391 // The new_bci and method_id is same as current_bci and current
392 // method_id after earlyret and step for recursive calls.
393 // Force the step by clearing the last location.
394 JvmtiEnvThreadStateIterator it(this);
395 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
396 ets->clear_current_location();
397 }
398 }
399
400 void JvmtiThreadState::oops_do(OopClosure* f) {
401 f->do_oop((oop*) &_earlyret_oop);
402 }