Thu, 09 Dec 2010 15:04:26 -0500
7004582: Add GetThisObject() function to JVMTI 1.2
Summary: Add 'GetThisObject' function
Reviewed-by: never, coleenp
1 /*
2 * Copyright (c) 1998, 2010, 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 */
25 #ifndef SHARE_VM_PRIMS_JVMTIEXPORT_HPP
26 #define SHARE_VM_PRIMS_JVMTIEXPORT_HPP
28 #include "jvmtifiles/jvmti.h"
29 #include "memory/allocation.hpp"
30 #include "memory/iterator.hpp"
31 #include "oops/oop.hpp"
32 #include "oops/oopsHierarchy.hpp"
33 #include "runtime/frame.hpp"
34 #include "runtime/handles.hpp"
35 #include "utilities/globalDefinitions.hpp"
36 #include "utilities/growableArray.hpp"
38 // Must be included after jvmti.h.
39 #include "code/jvmticmlr.h"
41 // Forward declarations
43 class JvmtiEventControllerPrivate;
44 class JvmtiManageCapabilities;
45 class JvmtiEnv;
46 class JvmtiThreadState;
47 class AttachOperation;
49 #ifndef JVMTI_KERNEL
50 #define JVMTI_SUPPORT_FLAG(key) \
51 private: \
52 static bool _##key; \
53 public: \
54 inline static void set_##key(bool on) { _##key = (on != 0); } \
55 inline static bool key() { return _##key; }
56 #else // JVMTI_KERNEL
57 #define JVMTI_SUPPORT_FLAG(key) \
58 private: \
59 const static bool _##key = false; \
60 public: \
61 inline static void set_##key(bool on) { report_unsupported(on); } \
62 inline static bool key() { return _##key; }
63 #endif // JVMTI_KERNEL
66 // This class contains the JVMTI interface for the rest of hotspot.
67 //
68 class JvmtiExport : public AllStatic {
69 private:
70 static int _field_access_count;
71 static int _field_modification_count;
73 static bool _can_access_local_variables;
74 static bool _can_hotswap_or_post_breakpoint;
75 static bool _can_modify_any_class;
76 static bool _can_walk_any_space;
78 JVMTI_SUPPORT_FLAG(can_get_source_debug_extension)
79 JVMTI_SUPPORT_FLAG(can_maintain_original_method_order)
80 JVMTI_SUPPORT_FLAG(can_post_interpreter_events)
81 JVMTI_SUPPORT_FLAG(can_post_on_exceptions)
82 JVMTI_SUPPORT_FLAG(can_post_breakpoint)
83 JVMTI_SUPPORT_FLAG(can_post_field_access)
84 JVMTI_SUPPORT_FLAG(can_post_field_modification)
85 JVMTI_SUPPORT_FLAG(can_post_method_entry)
86 JVMTI_SUPPORT_FLAG(can_post_method_exit)
87 JVMTI_SUPPORT_FLAG(can_pop_frame)
88 JVMTI_SUPPORT_FLAG(can_force_early_return)
90 friend class JvmtiEventControllerPrivate; // should only modify these flags
91 JVMTI_SUPPORT_FLAG(should_post_single_step)
92 JVMTI_SUPPORT_FLAG(should_post_field_access)
93 JVMTI_SUPPORT_FLAG(should_post_field_modification)
94 JVMTI_SUPPORT_FLAG(should_post_class_load)
95 JVMTI_SUPPORT_FLAG(should_post_class_prepare)
96 JVMTI_SUPPORT_FLAG(should_post_class_unload)
97 JVMTI_SUPPORT_FLAG(should_post_native_method_bind)
98 JVMTI_SUPPORT_FLAG(should_post_compiled_method_load)
99 JVMTI_SUPPORT_FLAG(should_post_compiled_method_unload)
100 JVMTI_SUPPORT_FLAG(should_post_dynamic_code_generated)
101 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_enter)
102 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_entered)
103 JVMTI_SUPPORT_FLAG(should_post_monitor_wait)
104 JVMTI_SUPPORT_FLAG(should_post_monitor_waited)
105 JVMTI_SUPPORT_FLAG(should_post_data_dump)
106 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start)
107 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish)
108 JVMTI_SUPPORT_FLAG(should_post_on_exceptions)
110 // ------ the below maybe don't have to be (but are for now)
111 // fixed conditions here ------------
112 // any events can be enabled
113 JVMTI_SUPPORT_FLAG(should_post_thread_life)
114 JVMTI_SUPPORT_FLAG(should_post_object_free)
115 JVMTI_SUPPORT_FLAG(should_post_resource_exhausted)
117 // we are holding objects on the heap - need to talk to GC - e.g.
118 // breakpoint info
119 JVMTI_SUPPORT_FLAG(should_clean_up_heap_objects)
120 JVMTI_SUPPORT_FLAG(should_post_vm_object_alloc)
122 // If flag cannot be implemented, give an error if on=true
123 static void report_unsupported(bool on);
125 // these should only be called by the friend class
126 friend class JvmtiManageCapabilities;
127 inline static void set_can_modify_any_class(bool on) { _can_modify_any_class = (on != 0); }
128 inline static void set_can_access_local_variables(bool on) { _can_access_local_variables = (on != 0); }
129 inline static void set_can_hotswap_or_post_breakpoint(bool on) { _can_hotswap_or_post_breakpoint = (on != 0); }
130 inline static void set_can_walk_any_space(bool on) { _can_walk_any_space = (on != 0); }
132 enum {
133 JVMTI_VERSION_MASK = 0x70000000,
134 JVMTI_VERSION_VALUE = 0x30000000,
135 JVMDI_VERSION_VALUE = 0x20000000
136 };
138 static void post_field_modification(JavaThread *thread, methodOop method, address location,
139 KlassHandle field_klass, Handle object, jfieldID field,
140 char sig_type, jvalue *value);
143 private:
144 // CompiledMethodUnload events are reported from the VM thread so they
145 // are collected in lists (of jmethodID/addresses) and the events are posted later
146 // from threads posting CompieldMethodLoad or DynamicCodeGenerated events.
147 static bool _have_pending_compiled_method_unload_events;
148 static GrowableArray<jmethodID>* _pending_compiled_method_unload_method_ids;
149 static GrowableArray<const void *>* _pending_compiled_method_unload_code_begins;
150 static JavaThread* _current_poster;
152 // tests if there are CompiledMethodUnload events pending
153 inline static bool have_pending_compiled_method_unload_events() {
154 return _have_pending_compiled_method_unload_events;
155 }
157 // posts any pending CompiledMethodUnload events.
158 static void post_pending_compiled_method_unload_events();
160 // Perform the actual notification to interested JvmtiEnvs.
161 static void post_compiled_method_unload_internal(JavaThread* self, jmethodID mid, const void* code_begin);
163 // posts a DynamicCodeGenerated event (internal/private implementation).
164 // The public post_dynamic_code_generated* functions make use of the
165 // internal implementation.
166 static void post_dynamic_code_generated_internal(const char *name, const void *code_begin, const void *code_end) KERNEL_RETURN;
169 // GenerateEvents support to allow posting of CompiledMethodLoad and
170 // DynamicCodeGenerated events for a given environment.
171 friend class JvmtiCodeBlobEvents;
173 static void post_compiled_method_load(JvmtiEnv* env, const jmethodID method, const jint length,
174 const void *code_begin, const jint map_length,
175 const jvmtiAddrLocationMap* map) KERNEL_RETURN;
176 static void post_dynamic_code_generated(JvmtiEnv* env, const char *name, const void *code_begin,
177 const void *code_end) KERNEL_RETURN;
179 // The RedefineClasses() API breaks some invariants in the "regular"
180 // system. For example, there are sanity checks when GC'ing nmethods
181 // that require the containing class to be unloading. However, when a
182 // method is redefined, the old method and nmethod can become GC'able
183 // without the containing class unloading. The state of becoming
184 // GC'able can be asynchronous to the RedefineClasses() call since
185 // the old method may still be running and cannot be GC'ed until
186 // after all old invocations have finished. Additionally, a method
187 // that has not been redefined may have an nmethod that depends on
188 // the redefined method. The dependent nmethod will get deopted in
189 // this case and may also be GC'able without the containing class
190 // being unloaded.
191 //
192 // This flag indicates whether RedefineClasses() has ever redefined
193 // one or more classes during the lifetime of the VM. The flag should
194 // only be set by the friend class and can be queried by other sub
195 // systems as needed to relax invariant checks.
196 static bool _has_redefined_a_class;
197 friend class VM_RedefineClasses;
198 inline static void set_has_redefined_a_class() {
199 _has_redefined_a_class = true;
200 }
202 // Flag to indicate if the compiler has recorded all dependencies. When the
203 // can_redefine_classes capability is enabled in the OnLoad phase then the compiler
204 // records all dependencies from startup. However if the capability is first
205 // enabled some time later then the dependencies recorded by the compiler
206 // are incomplete. This flag is used by RedefineClasses to know if the
207 // dependency information is complete or not.
208 static bool _all_dependencies_are_recorded;
210 public:
211 inline static bool has_redefined_a_class() {
212 return _has_redefined_a_class;
213 }
215 inline static bool all_dependencies_are_recorded() {
216 return _all_dependencies_are_recorded;
217 }
219 inline static void set_all_dependencies_are_recorded(bool on) {
220 _all_dependencies_are_recorded = (on != 0);
221 }
224 // let JVMTI know that the JVM_OnLoad code is running
225 static void enter_onload_phase();
227 // let JVMTI know that the VM isn't up yet (and JVM_OnLoad code isn't running)
228 static void enter_primordial_phase();
230 // let JVMTI know that the VM isn't up yet but JNI is live
231 static void enter_start_phase();
233 // let JVMTI know that the VM is fully up and running now
234 static void enter_live_phase();
236 // ------ can_* conditions (below) are set at OnLoad and never changed ------------
237 inline static bool can_modify_any_class() { return _can_modify_any_class; }
238 inline static bool can_access_local_variables() { return _can_access_local_variables; }
239 inline static bool can_hotswap_or_post_breakpoint() { return _can_hotswap_or_post_breakpoint; }
240 inline static bool can_walk_any_space() { return _can_walk_any_space; }
242 // field access management
243 static address get_field_access_count_addr();
245 // field modification management
246 static address get_field_modification_count_addr();
248 // -----------------
250 static bool is_jvmti_version(jint version) { return (version & JVMTI_VERSION_MASK) == JVMTI_VERSION_VALUE; }
251 static bool is_jvmdi_version(jint version) { return (version & JVMTI_VERSION_MASK) == JVMDI_VERSION_VALUE; }
252 static jint get_jvmti_interface(JavaVM *jvm, void **penv, jint version);
253 static void decode_version_values(jint version, int * major, int * minor,
254 int * micro);
256 // single stepping management methods
257 static void at_single_stepping_point(JavaThread *thread, methodOop method, address location) KERNEL_RETURN;
258 static void expose_single_stepping(JavaThread *thread) KERNEL_RETURN;
259 static bool hide_single_stepping(JavaThread *thread) KERNEL_RETURN_(return false;);
261 // Methods that notify the debugger that something interesting has happened in the VM.
262 static void post_vm_start ();
263 static void post_vm_initialized ();
264 static void post_vm_death ();
266 static void post_single_step (JavaThread *thread, methodOop method, address location) KERNEL_RETURN;
267 static void post_raw_breakpoint (JavaThread *thread, methodOop method, address location) KERNEL_RETURN;
269 static void post_exception_throw (JavaThread *thread, methodOop method, address location, oop exception) KERNEL_RETURN;
270 static void notice_unwind_due_to_exception (JavaThread *thread, methodOop method, address location, oop exception, bool in_handler_frame) KERNEL_RETURN;
272 static oop jni_GetField_probe (JavaThread *thread, jobject jobj,
273 oop obj, klassOop klass, jfieldID fieldID, bool is_static)
274 KERNEL_RETURN_(return NULL;);
275 static oop jni_GetField_probe_nh (JavaThread *thread, jobject jobj,
276 oop obj, klassOop klass, jfieldID fieldID, bool is_static)
277 KERNEL_RETURN_(return NULL;);
278 static void post_field_access_by_jni (JavaThread *thread, oop obj,
279 klassOop klass, jfieldID fieldID, bool is_static) KERNEL_RETURN;
280 static void post_field_access (JavaThread *thread, methodOop method,
281 address location, KlassHandle field_klass, Handle object, jfieldID field) KERNEL_RETURN;
282 static oop jni_SetField_probe (JavaThread *thread, jobject jobj,
283 oop obj, klassOop klass, jfieldID fieldID, bool is_static, char sig_type,
284 jvalue *value) KERNEL_RETURN_(return NULL;);
285 static oop jni_SetField_probe_nh (JavaThread *thread, jobject jobj,
286 oop obj, klassOop klass, jfieldID fieldID, bool is_static, char sig_type,
287 jvalue *value) KERNEL_RETURN_(return NULL;);
288 static void post_field_modification_by_jni(JavaThread *thread, oop obj,
289 klassOop klass, jfieldID fieldID, bool is_static, char sig_type,
290 jvalue *value);
291 static void post_raw_field_modification(JavaThread *thread, methodOop method,
292 address location, KlassHandle field_klass, Handle object, jfieldID field,
293 char sig_type, jvalue *value) KERNEL_RETURN;
295 static void post_method_entry (JavaThread *thread, methodOop method, frame current_frame) KERNEL_RETURN;
296 static void post_method_exit (JavaThread *thread, methodOop method, frame current_frame) KERNEL_RETURN;
298 static void post_class_load (JavaThread *thread, klassOop klass) KERNEL_RETURN;
299 static void post_class_unload (klassOop klass) KERNEL_RETURN;
300 static void post_class_prepare (JavaThread *thread, klassOop klass) KERNEL_RETURN;
302 static void post_thread_start (JavaThread *thread) KERNEL_RETURN;
303 static void post_thread_end (JavaThread *thread) KERNEL_RETURN;
305 // Support for java.lang.instrument agent loading.
306 static bool _should_post_class_file_load_hook;
307 inline static void set_should_post_class_file_load_hook(bool on) { _should_post_class_file_load_hook = on; }
308 inline static bool should_post_class_file_load_hook() { return _should_post_class_file_load_hook; }
309 static void post_class_file_load_hook(symbolHandle h_name, Handle class_loader,
310 Handle h_protection_domain,
311 unsigned char **data_ptr, unsigned char **end_ptr,
312 unsigned char **cached_data_ptr,
313 jint *cached_length_ptr);
314 static void post_native_method_bind(methodOop method, address* function_ptr) KERNEL_RETURN;
315 static void post_compiled_method_load(nmethod *nm) KERNEL_RETURN;
316 static void post_dynamic_code_generated(const char *name, const void *code_begin, const void *code_end) KERNEL_RETURN;
318 // used to post a CompiledMethodUnload event
319 static void post_compiled_method_unload(jmethodID mid, const void *code_begin) KERNEL_RETURN;
321 // similiar to post_dynamic_code_generated except that it can be used to
322 // post a DynamicCodeGenerated event while holding locks in the VM. Any event
323 // posted using this function is recorded by the enclosing event collector
324 // -- JvmtiDynamicCodeEventCollector.
325 static void post_dynamic_code_generated_while_holding_locks(const char* name, address code_begin, address code_end) KERNEL_RETURN;
327 static void post_garbage_collection_finish() KERNEL_RETURN;
328 static void post_garbage_collection_start() KERNEL_RETURN;
329 static void post_data_dump() KERNEL_RETURN;
330 static void post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) KERNEL_RETURN;
331 static void post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) KERNEL_RETURN;
332 static void post_monitor_wait(JavaThread *thread, oop obj, jlong timeout) KERNEL_RETURN;
333 static void post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) KERNEL_RETURN;
334 static void post_object_free(JvmtiEnv* env, jlong tag) KERNEL_RETURN;
335 static void post_resource_exhausted(jint resource_exhausted_flags, const char* detail) KERNEL_RETURN;
336 static void record_vm_internal_object_allocation(oop object) KERNEL_RETURN;
337 // Post objects collected by vm_object_alloc_event_collector.
338 static void post_vm_object_alloc(JavaThread *thread, oop object) KERNEL_RETURN;
339 // Collects vm internal objects for later event posting.
340 inline static void vm_object_alloc_event_collector(oop object) {
341 if (should_post_vm_object_alloc()) {
342 record_vm_internal_object_allocation(object);
343 }
344 }
346 static void cleanup_thread (JavaThread* thread) KERNEL_RETURN;
348 static void oops_do(OopClosure* f) KERNEL_RETURN;
350 static void transition_pending_onload_raw_monitors() KERNEL_RETURN;
352 #ifndef SERVICES_KERNEL
353 // attach support
354 static jint load_agent_library(AttachOperation* op, outputStream* out);
355 #endif // SERVICES_KERNEL
357 // SetNativeMethodPrefix support
358 static char** get_all_native_method_prefixes(int* count_ptr);
360 // call after CMS has completed referencing processing
361 static void cms_ref_processing_epilogue() KERNEL_RETURN;
362 };
364 // Support class used by JvmtiDynamicCodeEventCollector and others. It
365 // describes a single code blob by name and address range.
366 class JvmtiCodeBlobDesc : public CHeapObj {
367 private:
368 char _name[64];
369 address _code_begin;
370 address _code_end;
372 public:
373 JvmtiCodeBlobDesc(const char *name, address code_begin, address code_end) {
374 assert(name != NULL, "all code blobs must be named");
375 strncpy(_name, name, sizeof(_name));
376 _name[sizeof(_name)-1] = '\0';
377 _code_begin = code_begin;
378 _code_end = code_end;
379 }
380 char* name() { return _name; }
381 address code_begin() { return _code_begin; }
382 address code_end() { return _code_end; }
383 };
385 // JvmtiEventCollector is a helper class to setup thread for
386 // event collection.
387 class JvmtiEventCollector : public StackObj {
388 private:
389 JvmtiEventCollector* _prev; // Save previous one to support nested event collector.
391 public:
392 void setup_jvmti_thread_state(); // Set this collector in current thread.
393 void unset_jvmti_thread_state(); // Reset previous collector in current thread.
394 virtual bool is_dynamic_code_event() { return false; }
395 virtual bool is_vm_object_alloc_event(){ return false; }
396 JvmtiEventCollector *get_prev() { return _prev; }
397 };
399 // A JvmtiDynamicCodeEventCollector is a helper class for the JvmtiExport
400 // interface. It collects "dynamic code generated" events that are posted
401 // while holding locks. When the event collector goes out of scope the
402 // events will be posted.
403 //
404 // Usage :-
405 //
406 // {
407 // JvmtiDynamicCodeEventCollector event_collector;
408 // :
409 // { MutexLocker ml(...)
410 // :
411 // JvmtiExport::post_dynamic_code_generated_while_holding_locks(...)
412 // }
413 // // event collector goes out of scope => post events to profiler.
414 // }
416 class JvmtiDynamicCodeEventCollector : public JvmtiEventCollector {
417 private:
418 GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs; // collected code blob events
420 friend class JvmtiExport;
421 void register_stub(const char* name, address start, address end);
423 public:
424 JvmtiDynamicCodeEventCollector() KERNEL_RETURN;
425 ~JvmtiDynamicCodeEventCollector() KERNEL_RETURN;
426 bool is_dynamic_code_event() { return true; }
428 };
430 // Used to record vm internally allocated object oops and post
431 // vm object alloc event for objects visible to java world.
432 // Constructor enables JvmtiThreadState flag and all vm allocated
433 // objects are recorded in a growable array. When destructor is
434 // called the vm object alloc event is posted for each objects
435 // visible to java world.
436 // See jvm.cpp file for its usage.
437 //
438 class JvmtiVMObjectAllocEventCollector : public JvmtiEventCollector {
439 private:
440 GrowableArray<oop>* _allocated; // field to record vm internally allocated object oop.
441 bool _enable; // This flag is enabled in constructor and disabled
442 // in destructor before posting event. To avoid
443 // collection of objects allocated while running java code inside
444 // agent post_vm_object_alloc() event handler.
446 //GC support
447 void oops_do(OopClosure* f);
449 friend class JvmtiExport;
450 // Record vm allocated object oop.
451 inline void record_allocation(oop obj);
453 //GC support
454 static void oops_do_for_all_threads(OopClosure* f);
456 public:
457 JvmtiVMObjectAllocEventCollector() KERNEL_RETURN;
458 ~JvmtiVMObjectAllocEventCollector() KERNEL_RETURN;
459 bool is_vm_object_alloc_event() { return true; }
461 bool is_enabled() { return _enable; }
462 void set_enabled(bool on) { _enable = on; }
463 };
467 // Marker class to disable the posting of VMObjectAlloc events
468 // within its scope.
469 //
470 // Usage :-
471 //
472 // {
473 // NoJvmtiVMObjectAllocMark njm;
474 // :
475 // // VMObjAlloc event will not be posted
476 // JvmtiExport::vm_object_alloc_event_collector(obj);
477 // :
478 // }
480 class NoJvmtiVMObjectAllocMark : public StackObj {
481 private:
482 // enclosing collector if enabled, NULL otherwise
483 JvmtiVMObjectAllocEventCollector *_collector;
485 bool was_enabled() { return _collector != NULL; }
487 public:
488 NoJvmtiVMObjectAllocMark() KERNEL_RETURN;
489 ~NoJvmtiVMObjectAllocMark() KERNEL_RETURN;
490 };
493 // Base class for reporting GC events to JVMTI.
494 class JvmtiGCMarker : public StackObj {
495 private:
496 bool _full; // marks a "full" GC
497 unsigned int _invocation_count; // GC invocation count
498 protected:
499 JvmtiGCMarker(bool full) KERNEL_RETURN; // protected
500 ~JvmtiGCMarker() KERNEL_RETURN; // protected
501 };
504 // Support class used to report GC events to JVMTI. The class is stack
505 // allocated and should be placed in the doit() implementation of all
506 // vm operations that do a stop-the-world GC for failed allocation.
507 //
508 // Usage :-
509 //
510 // void VM_GenCollectForAllocation::doit() {
511 // JvmtiGCForAllocationMarker jgcm;
512 // :
513 // }
514 //
515 // If jvmti is not enabled the constructor and destructor is essentially
516 // a no-op (no overhead).
517 //
518 class JvmtiGCForAllocationMarker : public JvmtiGCMarker {
519 public:
520 JvmtiGCForAllocationMarker() : JvmtiGCMarker(false) {
521 }
522 };
524 // Support class used to report GC events to JVMTI. The class is stack
525 // allocated and should be placed in the doit() implementation of all
526 // vm operations that do a "full" stop-the-world GC. This class differs
527 // from JvmtiGCForAllocationMarker in that this class assumes that a
528 // "full" GC will happen.
529 //
530 // Usage :-
531 //
532 // void VM_GenCollectFull::doit() {
533 // JvmtiGCFullMarker jgcm;
534 // :
535 // }
536 //
537 class JvmtiGCFullMarker : public JvmtiGCMarker {
538 public:
539 JvmtiGCFullMarker() : JvmtiGCMarker(true) {
540 }
541 };
544 // JvmtiHideSingleStepping is a helper class for hiding
545 // internal single step events.
546 class JvmtiHideSingleStepping : public StackObj {
547 private:
548 bool _single_step_hidden;
549 JavaThread * _thread;
551 public:
552 JvmtiHideSingleStepping(JavaThread * thread) {
553 assert(thread != NULL, "sanity check");
555 _single_step_hidden = false;
556 _thread = thread;
557 if (JvmtiExport::should_post_single_step()) {
558 _single_step_hidden = JvmtiExport::hide_single_stepping(_thread);
559 }
560 }
562 ~JvmtiHideSingleStepping() {
563 if (_single_step_hidden) {
564 JvmtiExport::expose_single_stepping(_thread);
565 }
566 }
567 };
569 #endif // SHARE_VM_PRIMS_JVMTIEXPORT_HPP