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comparison src/share/vm/prims/jvmtiExport.hpp @ 0:a61af66fc99e jdk7-b24

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1 /*
2 * Copyright 1998-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 #ifndef _JAVA_JVMTIEXPORT_H_
26 #define _JAVA_JVMTIEXPORT_H_
27
28 // Forward declarations
29
30 class JvmtiEventControllerPrivate;
31 class JvmtiManageCapabilities;
32 class JvmtiEnv;
33 class JvmtiThreadState;
34 class AttachOperation;
35
36 #ifndef JVMTI_KERNEL
37 #define JVMTI_SUPPORT_FLAG(key) \
38 private: \
39 static bool _##key; \
40 public: \
41 inline static void set_##key(bool on) { _##key = (on != 0); } \
42 inline static bool key() { return _##key; }
43 #else // JVMTI_KERNEL
44 #define JVMTI_SUPPORT_FLAG(key) \
45 private: \
46 const static bool _##key = false; \
47 public: \
48 inline static void set_##key(bool on) { report_unsupported(on); } \
49 inline static bool key() { return _##key; }
50 #endif // JVMTI_KERNEL
51
52
53 // This class contains the JVMTI interface for the rest of hotspot.
54 //
55 class JvmtiExport : public AllStatic {
56 private:
57 static int _field_access_count;
58 static int _field_modification_count;
59
60 static bool _can_access_local_variables;
61 static bool _can_examine_or_deopt_anywhere;
62 static bool _can_hotswap_or_post_breakpoint;
63 static bool _can_modify_any_class;
64 static bool _can_walk_any_space;
65
66 JVMTI_SUPPORT_FLAG(can_get_source_debug_extension)
67 JVMTI_SUPPORT_FLAG(can_maintain_original_method_order)
68 JVMTI_SUPPORT_FLAG(can_post_interpreter_events)
69 JVMTI_SUPPORT_FLAG(can_post_exceptions)
70 JVMTI_SUPPORT_FLAG(can_post_breakpoint)
71 JVMTI_SUPPORT_FLAG(can_post_field_access)
72 JVMTI_SUPPORT_FLAG(can_post_field_modification)
73 JVMTI_SUPPORT_FLAG(can_post_method_entry)
74 JVMTI_SUPPORT_FLAG(can_post_method_exit)
75 JVMTI_SUPPORT_FLAG(can_pop_frame)
76 JVMTI_SUPPORT_FLAG(can_force_early_return)
77
78 friend class JvmtiEventControllerPrivate; // should only modify these flags
79 JVMTI_SUPPORT_FLAG(should_post_single_step)
80 JVMTI_SUPPORT_FLAG(should_post_field_access)
81 JVMTI_SUPPORT_FLAG(should_post_field_modification)
82 JVMTI_SUPPORT_FLAG(should_post_class_load)
83 JVMTI_SUPPORT_FLAG(should_post_class_prepare)
84 JVMTI_SUPPORT_FLAG(should_post_class_unload)
85 JVMTI_SUPPORT_FLAG(should_post_native_method_bind)
86 JVMTI_SUPPORT_FLAG(should_post_compiled_method_load)
87 JVMTI_SUPPORT_FLAG(should_post_compiled_method_unload)
88 JVMTI_SUPPORT_FLAG(should_post_dynamic_code_generated)
89 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_enter)
90 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_entered)
91 JVMTI_SUPPORT_FLAG(should_post_monitor_wait)
92 JVMTI_SUPPORT_FLAG(should_post_monitor_waited)
93 JVMTI_SUPPORT_FLAG(should_post_data_dump)
94 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start)
95 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish)
96
97 // ------ the below maybe don't have to be (but are for now)
98 // fixed conditions here ------------
99 // any events can be enabled
100 JVMTI_SUPPORT_FLAG(should_post_thread_life)
101 JVMTI_SUPPORT_FLAG(should_post_object_free)
102 JVMTI_SUPPORT_FLAG(should_post_resource_exhausted)
103
104 // we are holding objects on the heap - need to talk to GC - e.g.
105 // breakpoint info
106 JVMTI_SUPPORT_FLAG(should_clean_up_heap_objects)
107 JVMTI_SUPPORT_FLAG(should_post_vm_object_alloc)
108
109 // If flag cannot be implemented, give an error if on=true
110 static void report_unsupported(bool on);
111
112 // these should only be called by the friend class
113 friend class JvmtiManageCapabilities;
114 inline static void set_can_examine_or_deopt_anywhere(bool on) { _can_examine_or_deopt_anywhere = (on != 0); }
115 inline static void set_can_modify_any_class(bool on) { _can_modify_any_class = (on != 0); }
116 inline static void set_can_access_local_variables(bool on) { _can_access_local_variables = (on != 0); }
117 inline static void set_can_hotswap_or_post_breakpoint(bool on) { _can_hotswap_or_post_breakpoint = (on != 0); }
118 inline static void set_can_walk_any_space(bool on) { _can_walk_any_space = (on != 0); }
119
120 enum {
121 JVMTI_VERSION_MASK = 0x70000000,
122 JVMTI_VERSION_VALUE = 0x30000000,
123 JVMDI_VERSION_VALUE = 0x20000000
124 };
125
126 static void post_field_modification(JavaThread *thread, methodOop method, address location,
127 KlassHandle field_klass, Handle object, jfieldID field,
128 char sig_type, jvalue *value);
129
130
131 private:
132 // CompiledMethodUnload events are reported from the VM thread so they
133 // are collected in lists (of jmethodID/addresses) and the events are posted later
134 // from threads posting CompieldMethodLoad or DynamicCodeGenerated events.
135 static bool _have_pending_compiled_method_unload_events;
136 static GrowableArray<jmethodID>* _pending_compiled_method_unload_method_ids;
137 static GrowableArray<const void *>* _pending_compiled_method_unload_code_begins;
138 static JavaThread* _current_poster;
139
140 // tests if there are CompiledMethodUnload events pending
141 inline static bool have_pending_compiled_method_unload_events() {
142 return _have_pending_compiled_method_unload_events;
143 }
144
145 // posts any pending CompiledMethodUnload events.
146 static void post_pending_compiled_method_unload_events();
147
148 // posts a DynamicCodeGenerated event (internal/private implementation).
149 // The public post_dynamic_code_generated* functions make use of the
150 // internal implementation.
151 static void post_dynamic_code_generated_internal(const char *name, const void *code_begin, const void *code_end) KERNEL_RETURN;
152
153
154 // GenerateEvents support to allow posting of CompiledMethodLoad and
155 // DynamicCodeGenerated events for a given environment.
156 friend class JvmtiCodeBlobEvents;
157
158 static void post_compiled_method_load(JvmtiEnv* env, const jmethodID method, const jint length,
159 const void *code_begin, const jint map_length,
160 const jvmtiAddrLocationMap* map) KERNEL_RETURN;
161 static void post_dynamic_code_generated(JvmtiEnv* env, const char *name, const void *code_begin,
162 const void *code_end) KERNEL_RETURN;
163
164 // The RedefineClasses() API breaks some invariants in the "regular"
165 // system. For example, there are sanity checks when GC'ing nmethods
166 // that require the containing class to be unloading. However, when a
167 // method is redefined, the old method and nmethod can become GC'able
168 // without the containing class unloading. The state of becoming
169 // GC'able can be asynchronous to the RedefineClasses() call since
170 // the old method may still be running and cannot be GC'ed until
171 // after all old invocations have finished. Additionally, a method
172 // that has not been redefined may have an nmethod that depends on
173 // the redefined method. The dependent nmethod will get deopted in
174 // this case and may also be GC'able without the containing class
175 // being unloaded.
176 //
177 // This flag indicates whether RedefineClasses() has ever redefined
178 // one or more classes during the lifetime of the VM. The flag should
179 // only be set by the friend class and can be queried by other sub
180 // systems as needed to relax invariant checks.
181 static bool _has_redefined_a_class;
182 friend class VM_RedefineClasses;
183 inline static void set_has_redefined_a_class() {
184 _has_redefined_a_class = true;
185 }
186
187 // Flag to indicate if the compiler has recorded all dependencies. When the
188 // can_redefine_classes capability is enabled in the OnLoad phase then the compiler
189 // records all dependencies from startup. However if the capability is first
190 // enabled some time later then the dependencies recorded by the compiler
191 // are incomplete. This flag is used by RedefineClasses to know if the
192 // dependency information is complete or not.
193 static bool _all_dependencies_are_recorded;
194
195 public:
196 inline static bool has_redefined_a_class() {
197 return _has_redefined_a_class;
198 }
199
200 inline static bool all_dependencies_are_recorded() {
201 return _all_dependencies_are_recorded;
202 }
203
204 inline static void set_all_dependencies_are_recorded(bool on) {
205 _all_dependencies_are_recorded = (on != 0);
206 }
207
208
209 // let JVMTI know that the JVM_OnLoad code is running
210 static void enter_onload_phase();
211
212 // let JVMTI know that the VM isn't up yet (and JVM_OnLoad code isn't running)
213 static void enter_primordial_phase();
214
215 // let JVMTI know that the VM isn't up yet but JNI is live
216 static void enter_start_phase();
217
218 // let JVMTI know that the VM is fully up and running now
219 static void enter_live_phase();
220
221 // ------ can_* conditions (below) are set at OnLoad and never changed ------------
222 inline static bool can_examine_or_deopt_anywhere() { return _can_examine_or_deopt_anywhere; }
223 inline static bool can_modify_any_class() { return _can_modify_any_class; }
224 inline static bool can_access_local_variables() { return _can_access_local_variables; }
225 inline static bool can_hotswap_or_post_breakpoint() { return _can_hotswap_or_post_breakpoint; }
226 inline static bool can_walk_any_space() { return _can_walk_any_space; }
227
228 // field access management
229 static address get_field_access_count_addr();
230
231 // field modification management
232 static address get_field_modification_count_addr();
233
234 // -----------------
235
236 static bool is_jvmti_version(jint version) { return (version & JVMTI_VERSION_MASK) == JVMTI_VERSION_VALUE; }
237 static bool is_jvmdi_version(jint version) { return (version & JVMTI_VERSION_MASK) == JVMDI_VERSION_VALUE; }
238 static jint get_jvmti_interface(JavaVM *jvm, void **penv, jint version);
239
240 // single stepping management methods
241 static void at_single_stepping_point(JavaThread *thread, methodOop method, address location) KERNEL_RETURN;
242 static void expose_single_stepping(JavaThread *thread) KERNEL_RETURN;
243 static bool hide_single_stepping(JavaThread *thread) KERNEL_RETURN_(return false;);
244
245 // Methods that notify the debugger that something interesting has happened in the VM.
246 static void post_vm_start ();
247 static void post_vm_initialized ();
248 static void post_vm_death ();
249
250 static void post_single_step (JavaThread *thread, methodOop method, address location) KERNEL_RETURN;
251 static void post_raw_breakpoint (JavaThread *thread, methodOop method, address location) KERNEL_RETURN;
252
253 static void post_exception_throw (JavaThread *thread, methodOop method, address location, oop exception) KERNEL_RETURN;
254 static void notice_unwind_due_to_exception (JavaThread *thread, methodOop method, address location, oop exception, bool in_handler_frame) KERNEL_RETURN;
255
256 static oop jni_GetField_probe (JavaThread *thread, jobject jobj,
257 oop obj, klassOop klass, jfieldID fieldID, bool is_static)
258 KERNEL_RETURN_(return NULL;);
259 static oop jni_GetField_probe_nh (JavaThread *thread, jobject jobj,
260 oop obj, klassOop klass, jfieldID fieldID, bool is_static)
261 KERNEL_RETURN_(return NULL;);
262 static void post_field_access_by_jni (JavaThread *thread, oop obj,
263 klassOop klass, jfieldID fieldID, bool is_static) KERNEL_RETURN;
264 static void post_field_access (JavaThread *thread, methodOop method,
265 address location, KlassHandle field_klass, Handle object, jfieldID field) KERNEL_RETURN;
266 static oop jni_SetField_probe (JavaThread *thread, jobject jobj,
267 oop obj, klassOop klass, jfieldID fieldID, bool is_static, char sig_type,
268 jvalue *value) KERNEL_RETURN_(return NULL;);
269 static oop jni_SetField_probe_nh (JavaThread *thread, jobject jobj,
270 oop obj, klassOop klass, jfieldID fieldID, bool is_static, char sig_type,
271 jvalue *value) KERNEL_RETURN_(return NULL;);
272 static void post_field_modification_by_jni(JavaThread *thread, oop obj,
273 klassOop klass, jfieldID fieldID, bool is_static, char sig_type,
274 jvalue *value);
275 static void post_raw_field_modification(JavaThread *thread, methodOop method,
276 address location, KlassHandle field_klass, Handle object, jfieldID field,
277 char sig_type, jvalue *value) KERNEL_RETURN;
278
279 static void post_method_entry (JavaThread *thread, methodOop method, frame current_frame) KERNEL_RETURN;
280 static void post_method_exit (JavaThread *thread, methodOop method, frame current_frame) KERNEL_RETURN;
281
282 static void post_class_load (JavaThread *thread, klassOop klass) KERNEL_RETURN;
283 static void post_class_unload (klassOop klass) KERNEL_RETURN;
284 static void post_class_prepare (JavaThread *thread, klassOop klass) KERNEL_RETURN;
285
286 static void post_thread_start (JavaThread *thread) KERNEL_RETURN;
287 static void post_thread_end (JavaThread *thread) KERNEL_RETURN;
288
289 // Support for java.lang.instrument agent loading.
290 static bool _should_post_class_file_load_hook;
291 inline static void set_should_post_class_file_load_hook(bool on) { _should_post_class_file_load_hook = on; }
292 inline static bool should_post_class_file_load_hook() { return _should_post_class_file_load_hook; }
293 static void post_class_file_load_hook(symbolHandle h_name, Handle class_loader,
294 Handle h_protection_domain,
295 unsigned char **data_ptr, unsigned char **end_ptr,
296 unsigned char **cached_data_ptr,
297 jint *cached_length_ptr);
298 static void post_native_method_bind(methodOop method, address* function_ptr) KERNEL_RETURN;
299 static void post_compiled_method_load(nmethod *nm) KERNEL_RETURN;
300 static void post_dynamic_code_generated(const char *name, const void *code_begin, const void *code_end) KERNEL_RETURN;
301
302 // used at a safepoint to post a CompiledMethodUnload event
303 static void post_compiled_method_unload_at_safepoint(jmethodID mid, const void *code_begin) KERNEL_RETURN;
304
305 // similiar to post_dynamic_code_generated except that it can be used to
306 // post a DynamicCodeGenerated event while holding locks in the VM. Any event
307 // posted using this function is recorded by the enclosing event collector
308 // -- JvmtiDynamicCodeEventCollector.
309 static void post_dynamic_code_generated_while_holding_locks(const char* name, address code_begin, address code_end) KERNEL_RETURN;
310
311 static void post_garbage_collection_finish() KERNEL_RETURN;
312 static void post_garbage_collection_start() KERNEL_RETURN;
313 static void post_data_dump() KERNEL_RETURN;
314 static void post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) KERNEL_RETURN;
315 static void post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) KERNEL_RETURN;
316 static void post_monitor_wait(JavaThread *thread, oop obj, jlong timeout) KERNEL_RETURN;
317 static void post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) KERNEL_RETURN;
318 static void post_object_free(JvmtiEnv* env, jlong tag) KERNEL_RETURN;
319 static void post_resource_exhausted(jint resource_exhausted_flags, const char* detail) KERNEL_RETURN;
320 static void record_vm_internal_object_allocation(oop object) KERNEL_RETURN;
321 // Post objects collected by vm_object_alloc_event_collector.
322 static void post_vm_object_alloc(JavaThread *thread, oop object) KERNEL_RETURN;
323 // Collects vm internal objects for later event posting.
324 inline static void vm_object_alloc_event_collector(oop object) {
325 if (should_post_vm_object_alloc()) {
326 record_vm_internal_object_allocation(object);
327 }
328 }
329
330 static void cleanup_thread (JavaThread* thread) KERNEL_RETURN;
331
332 static void oops_do(OopClosure* f) KERNEL_RETURN;
333
334 static void transition_pending_onload_raw_monitors() KERNEL_RETURN;
335
336 #ifndef SERVICES_KERNEL
337 // attach support
338 static jint load_agent_library(AttachOperation* op, outputStream* out);
339 #endif // SERVICES_KERNEL
340
341 // SetNativeMethodPrefix support
342 static char** get_all_native_method_prefixes(int* count_ptr);
343
344 // call after CMS has completed referencing processing
345 static void cms_ref_processing_epilogue() KERNEL_RETURN;
346 };
347
348 // Support class used by JvmtiDynamicCodeEventCollector and others. It
349 // describes a single code blob by name and address range.
350 class JvmtiCodeBlobDesc : public CHeapObj {
351 private:
352 char _name[64];
353 address _code_begin;
354 address _code_end;
355
356 public:
357 JvmtiCodeBlobDesc(const char *name, address code_begin, address code_end) {
358 assert(name != NULL, "all code blobs must be named");
359 strncpy(_name, name, sizeof(_name));
360 _name[sizeof(_name)-1] = '\0';
361 _code_begin = code_begin;
362 _code_end = code_end;
363 }
364 char* name() { return _name; }
365 address code_begin() { return _code_begin; }
366 address code_end() { return _code_end; }
367 };
368
369 // JvmtiEventCollector is a helper class to setup thread for
370 // event collection.
371 class JvmtiEventCollector : public StackObj {
372 private:
373 JvmtiEventCollector* _prev; // Save previous one to support nested event collector.
374
375 public:
376 void setup_jvmti_thread_state(); // Set this collector in current thread.
377 void unset_jvmti_thread_state(); // Reset previous collector in current thread.
378 virtual bool is_dynamic_code_event() { return false; }
379 virtual bool is_vm_object_alloc_event(){ return false; }
380 JvmtiEventCollector *get_prev() { return _prev; }
381 };
382
383 // A JvmtiDynamicCodeEventCollector is a helper class for the JvmtiExport
384 // interface. It collects "dynamic code generated" events that are posted
385 // while holding locks. When the event collector goes out of scope the
386 // events will be posted.
387 //
388 // Usage :-
389 //
390 // {
391 // JvmtiDynamicCodeEventCollector event_collector;
392 // :
393 // { MutexLocker ml(...)
394 // :
395 // JvmtiExport::post_dynamic_code_generated_while_holding_locks(...)
396 // }
397 // // event collector goes out of scope => post events to profiler.
398 // }
399
400 class JvmtiDynamicCodeEventCollector : public JvmtiEventCollector {
401 private:
402 GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs; // collected code blob events
403
404 friend class JvmtiExport;
405 void register_stub(const char* name, address start, address end);
406
407 public:
408 JvmtiDynamicCodeEventCollector() KERNEL_RETURN;
409 ~JvmtiDynamicCodeEventCollector() KERNEL_RETURN;
410 bool is_dynamic_code_event() { return true; }
411
412 };
413
414 // Used to record vm internally allocated object oops and post
415 // vm object alloc event for objects visible to java world.
416 // Constructor enables JvmtiThreadState flag and all vm allocated
417 // objects are recorded in a growable array. When destructor is
418 // called the vm object alloc event is posted for each objects
419 // visible to java world.
420 // See jvm.cpp file for its usage.
421 //
422 class JvmtiVMObjectAllocEventCollector : public JvmtiEventCollector {
423 private:
424 GrowableArray<oop>* _allocated; // field to record vm internally allocated object oop.
425 bool _enable; // This flag is enabled in constructor and disabled
426 // in destructor before posting event. To avoid
427 // collection of objects allocated while running java code inside
428 // agent post_vm_object_alloc() event handler.
429
430 //GC support
431 void oops_do(OopClosure* f);
432
433 friend class JvmtiExport;
434 // Record vm allocated object oop.
435 inline void record_allocation(oop obj);
436
437 //GC support
438 static void oops_do_for_all_threads(OopClosure* f);
439
440 public:
441 JvmtiVMObjectAllocEventCollector() KERNEL_RETURN;
442 ~JvmtiVMObjectAllocEventCollector() KERNEL_RETURN;
443 bool is_vm_object_alloc_event() { return true; }
444
445 bool is_enabled() { return _enable; }
446 void set_enabled(bool on) { _enable = on; }
447 };
448
449
450
451 // Marker class to disable the posting of VMObjectAlloc events
452 // within its scope.
453 //
454 // Usage :-
455 //
456 // {
457 // NoJvmtiVMObjectAllocMark njm;
458 // :
459 // // VMObjAlloc event will not be posted
460 // JvmtiExport::vm_object_alloc_event_collector(obj);
461 // :
462 // }
463
464 class NoJvmtiVMObjectAllocMark : public StackObj {
465 private:
466 // enclosing collector if enabled, NULL otherwise
467 JvmtiVMObjectAllocEventCollector *_collector;
468
469 bool was_enabled() { return _collector != NULL; }
470
471 public:
472 NoJvmtiVMObjectAllocMark() KERNEL_RETURN;
473 ~NoJvmtiVMObjectAllocMark() KERNEL_RETURN;
474 };
475
476
477 // Base class for reporting GC events to JVMTI.
478 class JvmtiGCMarker : public StackObj {
479 private:
480 bool _full; // marks a "full" GC
481 unsigned int _invocation_count; // GC invocation count
482 protected:
483 JvmtiGCMarker(bool full) KERNEL_RETURN; // protected
484 ~JvmtiGCMarker() KERNEL_RETURN; // protected
485 };
486
487
488 // Support class used to report GC events to JVMTI. The class is stack
489 // allocated and should be placed in the doit() implementation of all
490 // vm operations that do a stop-the-world GC for failed allocation.
491 //
492 // Usage :-
493 //
494 // void VM_GenCollectForAllocation::doit() {
495 // JvmtiGCForAllocationMarker jgcm;
496 // :
497 // }
498 //
499 // If jvmti is not enabled the constructor and destructor is essentially
500 // a no-op (no overhead).
501 //
502 class JvmtiGCForAllocationMarker : public JvmtiGCMarker {
503 public:
504 JvmtiGCForAllocationMarker() : JvmtiGCMarker(false) {
505 }
506 };
507
508 // Support class used to report GC events to JVMTI. The class is stack
509 // allocated and should be placed in the doit() implementation of all
510 // vm operations that do a "full" stop-the-world GC. This class differs
511 // from JvmtiGCForAllocationMarker in that this class assumes that a
512 // "full" GC will happen.
513 //
514 // Usage :-
515 //
516 // void VM_GenCollectFull::doit() {
517 // JvmtiGCFullMarker jgcm;
518 // :
519 // }
520 //
521 class JvmtiGCFullMarker : public JvmtiGCMarker {
522 public:
523 JvmtiGCFullMarker() : JvmtiGCMarker(true) {
524 }
525 };
526
527
528 // JvmtiHideSingleStepping is a helper class for hiding
529 // internal single step events.
530 class JvmtiHideSingleStepping : public StackObj {
531 private:
532 bool _single_step_hidden;
533 JavaThread * _thread;
534
535 public:
536 JvmtiHideSingleStepping(JavaThread * thread) {
537 assert(thread != NULL, "sanity check");
538
539 _single_step_hidden = false;
540 _thread = thread;
541 if (JvmtiExport::should_post_single_step()) {
542 _single_step_hidden = JvmtiExport::hide_single_stepping(_thread);
543 }
544 }
545
546 ~JvmtiHideSingleStepping() {
547 if (_single_step_hidden) {
548 JvmtiExport::expose_single_stepping(_thread);
549 }
550 }
551 };
552
553 #endif /* _JAVA_JVMTIEXPORT_H_ */