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->print_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 #ifdef ASSERT
194 Thread* cur = Thread::current();
195 #endif
196 assert(get_thread() == cur || (cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()),
197 "frame pop data only accessible from same thread or at safepoint");
198 if (_frame_pops == NULL) {
199 _frame_pops = new JvmtiFramePops();
200 assert(_frame_pops != NULL, "_frame_pops != NULL");
201 }
202 return _frame_pops;
203 }
204
205
206 bool JvmtiEnvThreadState::has_frame_pops() {
207 return _frame_pops == NULL? false : (_frame_pops->length() > 0);
208 }
209
210 void JvmtiEnvThreadState::set_frame_pop(int frame_number) {
211 #ifdef ASSERT
212 Thread* cur = Thread::current();
213 #endif
214 assert(get_thread() == cur || (cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()),
215 "frame pop data only accessible from same thread or at safepoint");
216 JvmtiFramePop fpop(frame_number);
217 JvmtiEventController::set_frame_pop(this, fpop);
218 }
219
220
221 void JvmtiEnvThreadState::clear_frame_pop(int frame_number) {
222 #ifdef ASSERT
223 Thread* cur = Thread::current();
224 #endif
225 assert(get_thread() == cur || (cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()),
226 "frame pop data only accessible from same thread or at safepoint");
227 JvmtiFramePop fpop(frame_number);
228 JvmtiEventController::clear_frame_pop(this, fpop);
229 }
230
231
232 void JvmtiEnvThreadState::clear_to_frame_pop(int frame_number) {
233 #ifdef ASSERT
234 Thread* cur = Thread::current();
235 #endif
236 assert(get_thread() == cur || (cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()),
237 "frame pop data only accessible from same thread or at safepoint");
238 JvmtiFramePop fpop(frame_number);
239 JvmtiEventController::clear_to_frame_pop(this, fpop);
240 }
241
242
243 bool JvmtiEnvThreadState::is_frame_pop(int cur_frame_number) {
244 #ifdef ASSERT
245 Thread* cur = Thread::current();
246 #endif
247 assert(get_thread() == cur || (cur->is_VM_thread() && SafepointSynchronize::is_at_safepoint()),
248 "frame pop data only accessible from same thread or at safepoint");
249 if (!get_thread()->is_interp_only_mode() || _frame_pops == NULL) {
250 return false;
251 }
252 JvmtiFramePop fp(cur_frame_number);
253 return get_frame_pops()->contains(fp);
254 }
255
256
257 class VM_GetCurrentLocation : public VM_Operation {
258 private:
259 JavaThread *_thread;
260 jmethodID _method_id;
261 int _bci;
262
263 public:
264 VM_GetCurrentLocation(JavaThread *thread) {
265 _thread = thread;
266 }
267 VMOp_Type type() const { return VMOp_GetCurrentLocation; }
268 void doit() {
269 ResourceMark rmark; // _thread != Thread::current()
270 RegisterMap rm(_thread, false);
271 // There can be a race condition between a VM_Operation reaching a safepoint
272 // and the target thread exiting from Java execution.
273 // We must recheck the last Java frame still exists.
274 if (!_thread->is_exiting() && _thread->has_last_Java_frame()) {
275 javaVFrame* vf = _thread->last_java_vframe(&rm);
276 assert(vf != NULL, "must have last java frame");
277 Method* method = vf->method();
278 _method_id = method->jmethod_id();
279 _bci = vf->bci();
280 } else {
281 // Clear current location as the target thread has no Java frames anymore.
282 _method_id = (jmethodID)NULL;
283 _bci = 0;
284 }
285 }
286 void get_current_location(jmethodID *method_id, int *bci) {
287 *method_id = _method_id;
288 *bci = _bci;
289 }
290 };
291
292 void JvmtiEnvThreadState::reset_current_location(jvmtiEvent event_type, bool enabled) {
293 assert(event_type == JVMTI_EVENT_SINGLE_STEP || event_type == JVMTI_EVENT_BREAKPOINT,
294 "must be single-step or breakpoint event");
295
296 // Current location is used to detect the following:
297 // 1) a breakpoint event followed by single-stepping to the same bci
298 // 2) single-step to a bytecode that will be transformed to a fast version
299 // We skip to avoid posting the duplicate single-stepping event.
300
301 // If single-stepping is disabled, clear current location so that
302 // single-stepping to the same method and bcp at a later time will be
303 // detected if single-stepping is enabled at that time (see 4388912).
304
305 // If single-stepping is enabled, set the current location to the
306 // current method and bcp. This covers the following type of case,
307 // e.g., the debugger stepi command:
308 // - bytecode single stepped
309 // - SINGLE_STEP event posted and SINGLE_STEP event disabled
310 // - SINGLE_STEP event reenabled
311 // - bytecode rewritten to fast version
312
313 // If breakpoint event is disabled, clear current location only if
314 // single-stepping is not enabled. Otherwise, keep the thread location
315 // to detect any duplicate events.
316
317 if (enabled) {
318 // If enabling breakpoint, no need to reset.
319 // Can't do anything if empty stack.
320 if (event_type == JVMTI_EVENT_SINGLE_STEP && _thread->has_last_Java_frame()) {
321 jmethodID method_id;
322 int bci;
323 // The java thread stack may not be walkable for a running thread
324 // so get current location at safepoint.
325 VM_GetCurrentLocation op(_thread);
326 VMThread::execute(&op);
327 op.get_current_location(&method_id, &bci);
328 set_current_location(method_id, bci);
329 }
330 } else if (event_type == JVMTI_EVENT_SINGLE_STEP || !is_enabled(JVMTI_EVENT_SINGLE_STEP)) {
331 // If this is to disable breakpoint, also check if single-step is not enabled
332 clear_current_location();
333 }
334 }