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 "jvmtifiles/jvmtiEnv.hpp"
27 #include "memory/gcLocker.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_detected = false;
54 _exception_caught = false;
55 _debuggable = true;
56 _hide_single_stepping = false;
57 _hide_level = 0;
58 _pending_step_for_popframe = false;
59 _class_being_redefined = NULL;
60 _class_load_kind = jvmti_class_load_kind_load;
61 _head_env_thread_state = NULL;
62 _dynamic_code_event_collector = NULL;
63 _vm_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(No_Safepoint_Verifier 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(No_Safepoint_Verifier 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 No_Safepoint_Verifier
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(No_Safepoint_Verifier 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 #ifdef ASSERT
218 uint32_t debug_bits = 0;
219 #endif
220 assert(SafepointSynchronize::is_at_safepoint() ||
221 JvmtiEnv::is_thread_fully_suspended(get_thread(), false, &debug_bits),
222 "at safepoint or must be suspended");
223
224 if (!get_thread()->has_last_Java_frame()) return 0; // no Java frames
225
226 ResourceMark rm;
227 RegisterMap reg_map(get_thread());
228 javaVFrame *jvf = get_thread()->last_java_vframe(®_map);
229 int n = 0;
230 // tty->print_cr("CSD: counting frames on %s ...",
231 // JvmtiTrace::safe_get_thread_name(get_thread()));
232 while (jvf != NULL) {
233 Method* method = jvf->method();
234 // tty->print_cr("CSD: frame - method %s.%s - loc %d",
235 // method->klass_name()->as_C_string(),
236 // method->name()->as_C_string(),
237 // jvf->bci() );
238 jvf = jvf->java_sender();
239 n++;
240 }
241 // tty->print_cr("CSD: frame count: %d", n);
242 return n;
243 }
244
245
246 void JvmtiThreadState::invalidate_cur_stack_depth() {
247 Thread *cur = Thread::current();
248
249 guarantee((cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()) ||
250 (JavaThread *)cur == get_thread(),
251 "must be current thread or at safepont");
252
253 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
254 }
255
256 void JvmtiThreadState::incr_cur_stack_depth() {
257 guarantee(JavaThread::current() == get_thread(), "must be current thread");
258
259 if (!is_interp_only_mode()) {
260 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
261 }
262 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
263 ++_cur_stack_depth;
264 }
265 }
266
267 void JvmtiThreadState::decr_cur_stack_depth() {
268 guarantee(JavaThread::current() == get_thread(), "must be current thread");
269
270 if (!is_interp_only_mode()) {
271 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
272 }
273 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
274 --_cur_stack_depth;
275 assert(_cur_stack_depth >= 0, "incr/decr_cur_stack_depth mismatch");
276 }
277 }
278
279 int JvmtiThreadState::cur_stack_depth() {
280 Thread *cur = Thread::current();
281
282 guarantee((cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()) ||
283 (JavaThread *)cur == get_thread(),
284 "must be current thread or at safepont");
285
286 if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) {
287 _cur_stack_depth = count_frames();
288 } else {
289 // heavy weight assert
290 assert(_cur_stack_depth == count_frames(),
291 "cur_stack_depth out of sync");
292 }
293 return _cur_stack_depth;
294 }
295
296 bool JvmtiThreadState::may_be_walked() {
297 return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread()));
298 }
299
300
301 void JvmtiThreadState::process_pending_step_for_popframe() {
302 // We are single stepping as the last part of the PopFrame() dance
303 // so we have some house keeping to do.
304
305 JavaThread *thr = get_thread();
306 if (thr->popframe_condition() != JavaThread::popframe_inactive) {
307 // If the popframe_condition field is not popframe_inactive, then
308 // we missed all of the popframe_field cleanup points:
309 //
310 // - unpack_frames() was not called (nothing to deopt)
311 // - remove_activation_preserving_args_entry() was not called
312 // (did not get suspended in a call_vm() family call and did
313 // not complete a call_vm() family call on the way here)
314 thr->clear_popframe_condition();
315 }
316
317 // clearing the flag indicates we are done with the PopFrame() dance
318 clr_pending_step_for_popframe();
319
320 // If exception was thrown in this frame, need to reset jvmti thread state.
321 // Single stepping may not get enabled correctly by the agent since
322 // exception state is passed in MethodExit event which may be sent at some
323 // time in the future. JDWP agent ignores MethodExit events if caused by
324 // an exception.
325 //
326 if (is_exception_detected()) {
327 clear_exception_detected();
328 }
329 // If step is pending for popframe then it may not be
330 // a repeat step. The new_bci and method_id is same as current_bci
331 // and current method_id after pop and step for recursive calls.
332 // Force the step by clearing the last location.
333 JvmtiEnvThreadStateIterator it(this);
334 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
335 ets->clear_current_location();
336 }
337 }
338
339
340 // Class: JvmtiThreadState
341 // Function: update_for_pop_top_frame
342 // Description:
343 // This function removes any frame pop notification request for
344 // the top frame and invalidates both the current stack depth and
345 // all cached frameIDs.
346 //
347 // Called by: PopFrame
348 //
349 void JvmtiThreadState::update_for_pop_top_frame() {
350 if (is_interp_only_mode()) {
351 // remove any frame pop notification request for the top frame
352 // in any environment
353 int popframe_number = cur_stack_depth();
354 {
355 JvmtiEnvThreadStateIterator it(this);
356 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
357 if (ets->is_frame_pop(popframe_number)) {
358 ets->clear_frame_pop(popframe_number);
359 }
360 }
361 }
362 // force stack depth to be recalculated
363 invalidate_cur_stack_depth();
364 } else {
365 assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set");
366 }
367 }
368
369
370 void JvmtiThreadState::process_pending_step_for_earlyret() {
371 // We are single stepping as the last part of the ForceEarlyReturn
372 // dance so we have some house keeping to do.
373
374 if (is_earlyret_pending()) {
375 // If the earlyret_state field is not earlyret_inactive, then
376 // we missed all of the earlyret_field cleanup points:
377 //
378 // - remove_activation() was not called
379 // (did not get suspended in a call_vm() family call and did
380 // not complete a call_vm() family call on the way here)
381 //
382 // One legitimate way for us to miss all the cleanup points is
383 // if we got here right after handling a compiled return. If that
384 // is the case, then we consider our return from compiled code to
385 // complete the ForceEarlyReturn request and we clear the condition.
386 clr_earlyret_pending();
387 set_earlyret_oop(NULL);
388 clr_earlyret_value();
389 }
390
391 // clearing the flag indicates we are done with
392 // the ForceEarlyReturn() dance
393 clr_pending_step_for_earlyret();
394
395 // If exception was thrown in this frame, need to reset jvmti thread state.
396 // Single stepping may not get enabled correctly by the agent since
397 // exception state is passed in MethodExit event which may be sent at some
398 // time in the future. JDWP agent ignores MethodExit events if caused by
399 // an exception.
400 //
401 if (is_exception_detected()) {
402 clear_exception_detected();
403 }
404 // If step is pending for earlyret then it may not be a repeat step.
405 // The new_bci and method_id is same as current_bci and current
406 // method_id after earlyret and step for recursive calls.
407 // Force the step by clearing the last location.
408 JvmtiEnvThreadStateIterator it(this);
409 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
410 ets->clear_current_location();
411 }
412 }
413
414 void JvmtiThreadState::oops_do(OopClosure* f) {
415 f->do_oop((oop*) &_earlyret_oop);
416 }