1 /*
2 * Copyright (c) 2003, 2012, 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
67 // JVMTI ForceEarlyReturn support
68 _pending_step_for_earlyret = false;
69 _earlyret_state = earlyret_inactive;
70 _earlyret_tos = ilgl;
71 _earlyret_value.j = 0L;
72 _earlyret_oop = NULL;
73
74 // add all the JvmtiEnvThreadState to the new JvmtiThreadState
75 {
76 JvmtiEnvIterator it;
77 for (JvmtiEnvBase* env = it.first(); env != NULL; env = it.next(env)) {
78 if (env->is_valid()) {
79 add_env(env);
80 }
81 }
82 }
83
84 // link us into the list
85 {
86 // The thread state list manipulation code must not have safepoints.
87 // See periodic_clean_up().
88 debug_only(No_Safepoint_Verifier nosafepoint;)
89
90 _prev = NULL;
91 _next = _head;
92 if (_head != NULL) {
93 _head->_prev = this;
94 }
95 _head = this;
96 }
97
98 // set this as the state for the thread
99 thread->set_jvmti_thread_state(this);
100 }
101
102
103 JvmtiThreadState::~JvmtiThreadState() {
104 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
105
106 // clear this as the state for the thread
107 get_thread()->set_jvmti_thread_state(NULL);
108
109 // zap our env thread states
110 {
111 JvmtiEnvBase::entering_dying_thread_env_iteration();
112 JvmtiEnvThreadStateIterator it(this);
113 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ) {
114 JvmtiEnvThreadState* zap = ets;
115 ets = it.next(ets);
116 delete zap;
117 }
118 JvmtiEnvBase::leaving_dying_thread_env_iteration();
119 }
120
121 // remove us from the list
122 {
123 // The thread state list manipulation code must not have safepoints.
124 // See periodic_clean_up().
125 debug_only(No_Safepoint_Verifier nosafepoint;)
126
127 if (_prev == NULL) {
128 assert(_head == this, "sanity check");
129 _head = _next;
130 } else {
131 assert(_head != this, "sanity check");
132 _prev->_next = _next;
133 }
134 if (_next != NULL) {
135 _next->_prev = _prev;
136 }
137 _next = NULL;
138 _prev = NULL;
139 }
140 }
141
142
143 void
144 JvmtiThreadState::periodic_clean_up() {
145 assert(SafepointSynchronize::is_at_safepoint(), "at safepoint");
146
147 // This iteration is initialized with "_head" instead of "JvmtiThreadState::first()"
148 // because the latter requires the JvmtiThreadState_lock.
149 // This iteration is safe at a safepoint as well, see the No_Safepoint_Verifier
150 // asserts at all list manipulation sites.
151 for (JvmtiThreadState *state = _head; state != NULL; state = state->next()) {
152 // For each environment thread state corresponding to an invalid environment
153 // unlink it from the list and deallocate it.
154 JvmtiEnvThreadStateIterator it(state);
155 JvmtiEnvThreadState* previous_ets = NULL;
156 JvmtiEnvThreadState* ets = it.first();
157 while (ets != NULL) {
158 if (ets->get_env()->is_valid()) {
159 previous_ets = ets;
160 ets = it.next(ets);
161 } else {
162 // This one isn't valid, remove it from the list and deallocate it
163 JvmtiEnvThreadState* defunct_ets = ets;
164 ets = ets->next();
165 if (previous_ets == NULL) {
166 assert(state->head_env_thread_state() == defunct_ets, "sanity check");
167 state->set_head_env_thread_state(ets);
168 } else {
169 previous_ets->set_next(ets);
170 }
171 delete defunct_ets;
172 }
173 }
174 }
175 }
176
177 void JvmtiThreadState::add_env(JvmtiEnvBase *env) {
178 assert(JvmtiThreadState_lock->is_locked(), "sanity check");
179
180 JvmtiEnvThreadState *new_ets = new JvmtiEnvThreadState(_thread, env);
181 // add this environment thread state to the end of the list (order is important)
182 {
183 // list deallocation (which occurs at a safepoint) cannot occur simultaneously
184 debug_only(No_Safepoint_Verifier nosafepoint;)
185
186 JvmtiEnvThreadStateIterator it(this);
187 JvmtiEnvThreadState* previous_ets = NULL;
188 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
189 previous_ets = ets;
190 }
191 if (previous_ets == NULL) {
192 set_head_env_thread_state(new_ets);
193 } else {
194 previous_ets->set_next(new_ets);
195 }
196 }
197 }
198
199
200
201
202 void JvmtiThreadState::enter_interp_only_mode() {
203 assert(_thread->get_interp_only_mode() == 0, "entering interp only when mode not zero");
204 _thread->increment_interp_only_mode();
205 }
206
207
208 void JvmtiThreadState::leave_interp_only_mode() {
209 assert(_thread->get_interp_only_mode() == 1, "leaving interp only when mode not one");
210 _thread->decrement_interp_only_mode();
211 }
212
213
214 // Helper routine used in several places
215 int JvmtiThreadState::count_frames() {
216 #ifdef ASSERT
217 uint32_t debug_bits = 0;
218 #endif
219 assert(SafepointSynchronize::is_at_safepoint() ||
220 JvmtiEnv::is_thread_fully_suspended(get_thread(), false, &debug_bits),
221 "at safepoint or must be suspended");
222
223 if (!get_thread()->has_last_Java_frame()) return 0; // no Java frames
224
225 ResourceMark rm;
226 RegisterMap reg_map(get_thread());
227 javaVFrame *jvf = get_thread()->last_java_vframe(®_map);
228 int n = 0;
229 // tty->print_cr("CSD: counting frames on %s ...",
230 // JvmtiTrace::safe_get_thread_name(get_thread()));
231 while (jvf != NULL) {
232 Method* method = jvf->method();
233 // tty->print_cr("CSD: frame - method %s.%s - loc %d",
234 // method->klass_name()->as_C_string(),
235 // method->name()->as_C_string(),
236 // jvf->bci() );
237 jvf = jvf->java_sender();
238 n++;
239 }
240 // tty->print_cr("CSD: frame count: %d", n);
241 return n;
242 }
243
244
245 void JvmtiThreadState::invalidate_cur_stack_depth() {
246 Thread *cur = Thread::current();
247 uint32_t debug_bits = 0;
248
249 // The caller can be the VMThread at a safepoint, the current thread
250 // or the target thread must be suspended.
251 guarantee((cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()) ||
252 (JavaThread *)cur == get_thread() ||
253 JvmtiEnv::is_thread_fully_suspended(get_thread(), false, &debug_bits),
254 "sanity check");
255
256 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
257 }
258
259 void JvmtiThreadState::incr_cur_stack_depth() {
260 guarantee(JavaThread::current() == get_thread(), "must be current thread");
261
262 if (!is_interp_only_mode()) {
263 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
264 }
265 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
266 ++_cur_stack_depth;
267 }
268 }
269
270 void JvmtiThreadState::decr_cur_stack_depth() {
271 guarantee(JavaThread::current() == get_thread(), "must be current thread");
272
273 if (!is_interp_only_mode()) {
274 _cur_stack_depth = UNKNOWN_STACK_DEPTH;
275 }
276 if (_cur_stack_depth != UNKNOWN_STACK_DEPTH) {
277 --_cur_stack_depth;
278 assert(_cur_stack_depth >= 0, "incr/decr_cur_stack_depth mismatch");
279 }
280 }
281
282 int JvmtiThreadState::cur_stack_depth() {
283 uint32_t debug_bits = 0;
284 guarantee(JavaThread::current() == get_thread() ||
285 JvmtiEnv::is_thread_fully_suspended(get_thread(), false, &debug_bits),
286 "must be current thread or suspended");
287
288 if (!is_interp_only_mode() || _cur_stack_depth == UNKNOWN_STACK_DEPTH) {
289 _cur_stack_depth = count_frames();
290 } else {
291 // heavy weight assert
292 assert(_cur_stack_depth == count_frames(),
293 "cur_stack_depth out of sync");
294 }
295 return _cur_stack_depth;
296 }
297
298 bool JvmtiThreadState::may_be_walked() {
299 return (get_thread()->is_being_ext_suspended() || (JavaThread::current() == get_thread()));
300 }
301
302
303 void JvmtiThreadState::process_pending_step_for_popframe() {
304 // We are single stepping as the last part of the PopFrame() dance
305 // so we have some house keeping to do.
306
307 JavaThread *thr = get_thread();
308 if (thr->popframe_condition() != JavaThread::popframe_inactive) {
309 // If the popframe_condition field is not popframe_inactive, then
310 // we missed all of the popframe_field cleanup points:
311 //
312 // - unpack_frames() was not called (nothing to deopt)
313 // - remove_activation_preserving_args_entry() was not called
314 // (did not get suspended in a call_vm() family call and did
315 // not complete a call_vm() family call on the way here)
316 thr->clear_popframe_condition();
317 }
318
319 // clearing the flag indicates we are done with the PopFrame() dance
320 clr_pending_step_for_popframe();
321
322 // If exception was thrown in this frame, need to reset jvmti thread state.
323 // Single stepping may not get enabled correctly by the agent since
324 // exception state is passed in MethodExit event which may be sent at some
325 // time in the future. JDWP agent ignores MethodExit events if caused by
326 // an exception.
327 //
328 if (is_exception_detected()) {
329 clear_exception_detected();
330 }
331 // If step is pending for popframe then it may not be
332 // a repeat step. The new_bci and method_id is same as current_bci
333 // and current method_id after pop and step for recursive calls.
334 // Force the step by clearing the last location.
335 JvmtiEnvThreadStateIterator it(this);
336 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
337 ets->clear_current_location();
338 }
339 }
340
341
342 // Class: JvmtiThreadState
343 // Function: update_for_pop_top_frame
344 // Description:
345 // This function removes any frame pop notification request for
346 // the top frame and invalidates both the current stack depth and
347 // all cached frameIDs.
348 //
349 // Called by: PopFrame
350 //
351 void JvmtiThreadState::update_for_pop_top_frame() {
352 if (is_interp_only_mode()) {
353 // remove any frame pop notification request for the top frame
354 // in any environment
355 int popframe_number = cur_stack_depth();
356 {
357 JvmtiEnvThreadStateIterator it(this);
358 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
359 if (ets->is_frame_pop(popframe_number)) {
360 ets->clear_frame_pop(popframe_number);
361 }
362 }
363 }
364 // force stack depth to be recalculated
365 invalidate_cur_stack_depth();
366 } else {
367 assert(!is_enabled(JVMTI_EVENT_FRAME_POP), "Must have no framepops set");
368 }
369 }
370
371
372 void JvmtiThreadState::process_pending_step_for_earlyret() {
373 // We are single stepping as the last part of the ForceEarlyReturn
374 // dance so we have some house keeping to do.
375
376 if (is_earlyret_pending()) {
377 // If the earlyret_state field is not earlyret_inactive, then
378 // we missed all of the earlyret_field cleanup points:
379 //
380 // - remove_activation() was not called
381 // (did not get suspended in a call_vm() family call and did
382 // not complete a call_vm() family call on the way here)
383 //
384 // One legitimate way for us to miss all the cleanup points is
385 // if we got here right after handling a compiled return. If that
386 // is the case, then we consider our return from compiled code to
387 // complete the ForceEarlyReturn request and we clear the condition.
388 clr_earlyret_pending();
389 set_earlyret_oop(NULL);
390 clr_earlyret_value();
391 }
392
393 // clearing the flag indicates we are done with
394 // the ForceEarlyReturn() dance
395 clr_pending_step_for_earlyret();
396
397 // If exception was thrown in this frame, need to reset jvmti thread state.
398 // Single stepping may not get enabled correctly by the agent since
399 // exception state is passed in MethodExit event which may be sent at some
400 // time in the future. JDWP agent ignores MethodExit events if caused by
401 // an exception.
402 //
403 if (is_exception_detected()) {
404 clear_exception_detected();
405 }
406 // If step is pending for earlyret then it may not be a repeat step.
407 // The new_bci and method_id is same as current_bci and current
408 // method_id after earlyret and step for recursive calls.
409 // Force the step by clearing the last location.
410 JvmtiEnvThreadStateIterator it(this);
411 for (JvmtiEnvThreadState* ets = it.first(); ets != NULL; ets = it.next(ets)) {
412 ets->clear_current_location();
413 }
414 }
415
416 void JvmtiThreadState::oops_do(OopClosure* f) {
417 f->do_oop((oop*) &_earlyret_oop);
418 }