1 /* 2 * Copyright (c) 1998, 2013, 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 #ifndef SHARE_VM_PRIMS_JVMTIEXPORT_HPP 26 #define SHARE_VM_PRIMS_JVMTIEXPORT_HPP 27 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" 37 #include "utilities/macros.hpp" 38 39 // Must be included after jvmti.h. 40 #include "code/jvmticmlr.h" 41 42 // Forward declarations 43 44 class JvmtiEventControllerPrivate; 45 class JvmtiManageCapabilities; 46 class JvmtiEnv; 47 class JvmtiThreadState; 48 class AttachOperation; 49 50 #define JVMTI_SUPPORT_FLAG(key) \ 51 private: \ 52 static bool _##key; \ 53 public: \ 54 inline static void set_##key(bool on) { \ 55 JVMTI_ONLY(_##key = (on != 0)); \ 56 NOT_JVMTI(report_unsupported(on)); \ 57 } \ 58 inline static bool key() { \ 59 JVMTI_ONLY(return _##key); \ 60 NOT_JVMTI(return false); \ 61 } 62 63 64 // This class contains the JVMTI interface for the rest of hotspot. 65 // 66 class JvmtiExport : public AllStatic { 67 friend class VMStructs; 68 friend class CompileReplay; 69 70 private: 71 72 #if INCLUDE_JVMTI 73 static int _field_access_count; 74 static int _field_modification_count; 75 76 static bool _can_access_local_variables; 77 static bool _can_hotswap_or_post_breakpoint; 78 static bool _can_modify_any_class; 79 static bool _can_walk_any_space; 80 #endif // INCLUDE_JVMTI 81 82 JVMTI_SUPPORT_FLAG(can_get_source_debug_extension) 83 JVMTI_SUPPORT_FLAG(can_maintain_original_method_order) 84 JVMTI_SUPPORT_FLAG(can_post_interpreter_events) 85 JVMTI_SUPPORT_FLAG(can_post_on_exceptions) 86 JVMTI_SUPPORT_FLAG(can_post_breakpoint) 87 JVMTI_SUPPORT_FLAG(can_post_field_access) 88 JVMTI_SUPPORT_FLAG(can_post_field_modification) 89 JVMTI_SUPPORT_FLAG(can_post_method_entry) 90 JVMTI_SUPPORT_FLAG(can_post_method_exit) 91 JVMTI_SUPPORT_FLAG(can_pop_frame) 92 JVMTI_SUPPORT_FLAG(can_force_early_return) 93 94 friend class JvmtiEventControllerPrivate; // should only modify these flags 95 JVMTI_SUPPORT_FLAG(should_post_single_step) 96 JVMTI_SUPPORT_FLAG(should_post_field_access) 97 JVMTI_SUPPORT_FLAG(should_post_field_modification) 98 JVMTI_SUPPORT_FLAG(should_post_class_load) 99 JVMTI_SUPPORT_FLAG(should_post_class_prepare) 100 JVMTI_SUPPORT_FLAG(should_post_class_unload) 101 JVMTI_SUPPORT_FLAG(should_post_native_method_bind) 102 JVMTI_SUPPORT_FLAG(should_post_compiled_method_load) 103 JVMTI_SUPPORT_FLAG(should_post_compiled_method_unload) 104 JVMTI_SUPPORT_FLAG(should_post_dynamic_code_generated) 105 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_enter) 106 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_entered) 107 JVMTI_SUPPORT_FLAG(should_post_monitor_wait) 108 JVMTI_SUPPORT_FLAG(should_post_monitor_waited) 109 JVMTI_SUPPORT_FLAG(should_post_data_dump) 110 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start) 111 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish) 112 JVMTI_SUPPORT_FLAG(should_post_on_exceptions) 113 114 // ------ the below maybe don't have to be (but are for now) 115 // fixed conditions here ------------ 116 // any events can be enabled 117 JVMTI_SUPPORT_FLAG(should_post_thread_life) 118 JVMTI_SUPPORT_FLAG(should_post_object_free) 119 JVMTI_SUPPORT_FLAG(should_post_resource_exhausted) 120 121 // we are holding objects on the heap - need to talk to GC - e.g. 122 // breakpoint info 123 JVMTI_SUPPORT_FLAG(should_clean_up_heap_objects) 124 JVMTI_SUPPORT_FLAG(should_post_vm_object_alloc) 125 126 // If flag cannot be implemented, give an error if on=true 127 static void report_unsupported(bool on); 128 129 // these should only be called by the friend class 130 friend class JvmtiManageCapabilities; 131 inline static void set_can_modify_any_class(bool on) { 132 JVMTI_ONLY(_can_modify_any_class = (on != 0);) 133 } 134 inline static void set_can_access_local_variables(bool on) { 135 JVMTI_ONLY(_can_access_local_variables = (on != 0);) 136 } 137 inline static void set_can_hotswap_or_post_breakpoint(bool on) { 138 JVMTI_ONLY(_can_hotswap_or_post_breakpoint = (on != 0);) 139 } 140 inline static void set_can_walk_any_space(bool on) { 141 JVMTI_ONLY(_can_walk_any_space = (on != 0);) 142 } 143 144 enum { 145 JVMTI_VERSION_MASK = 0x70000000, 146 JVMTI_VERSION_VALUE = 0x30000000, 147 JVMDI_VERSION_VALUE = 0x20000000 148 }; 149 150 static void post_field_modification(JavaThread *thread, Method* method, address location, 151 KlassHandle field_klass, Handle object, jfieldID field, 152 char sig_type, jvalue *value); 153 154 155 // posts a DynamicCodeGenerated event (internal/private implementation). 156 // The public post_dynamic_code_generated* functions make use of the 157 // internal implementation. Also called from JvmtiDeferredEvent::post() 158 static void post_dynamic_code_generated_internal(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN; 159 160 private: 161 162 // GenerateEvents support to allow posting of CompiledMethodLoad and 163 // DynamicCodeGenerated events for a given environment. 164 friend class JvmtiCodeBlobEvents; 165 166 static void post_compiled_method_load(JvmtiEnv* env, const jmethodID method, const jint length, 167 const void *code_begin, const jint map_length, 168 const jvmtiAddrLocationMap* map) NOT_JVMTI_RETURN; 169 static void post_dynamic_code_generated(JvmtiEnv* env, const char *name, const void *code_begin, 170 const void *code_end) NOT_JVMTI_RETURN; 171 172 // The RedefineClasses() API breaks some invariants in the "regular" 173 // system. For example, there are sanity checks when GC'ing nmethods 174 // that require the containing class to be unloading. However, when a 175 // method is redefined, the old method and nmethod can become GC'able 176 // without the containing class unloading. The state of becoming 177 // GC'able can be asynchronous to the RedefineClasses() call since 178 // the old method may still be running and cannot be GC'ed until 179 // after all old invocations have finished. Additionally, a method 180 // that has not been redefined may have an nmethod that depends on 181 // the redefined method. The dependent nmethod will get deopted in 182 // this case and may also be GC'able without the containing class 183 // being unloaded. 184 // 185 // This flag indicates whether RedefineClasses() has ever redefined 186 // one or more classes during the lifetime of the VM. The flag should 187 // only be set by the friend class and can be queried by other sub 188 // systems as needed to relax invariant checks. 189 static bool _has_redefined_a_class; 190 friend class VM_RedefineClasses; 191 inline static void set_has_redefined_a_class() { 192 JVMTI_ONLY(_has_redefined_a_class = true;) 193 } 194 // Flag to indicate if the compiler has recorded all dependencies. When the 195 // can_redefine_classes capability is enabled in the OnLoad phase then the compiler 196 // records all dependencies from startup. However if the capability is first 197 // enabled some time later then the dependencies recorded by the compiler 198 // are incomplete. This flag is used by RedefineClasses to know if the 199 // dependency information is complete or not. 200 static bool _all_dependencies_are_recorded; 201 202 public: 203 inline static bool has_redefined_a_class() { 204 JVMTI_ONLY(return _has_redefined_a_class); 205 NOT_JVMTI(return false); 206 } 207 208 inline static bool all_dependencies_are_recorded() { 209 return _all_dependencies_are_recorded; 210 } 211 212 inline static void set_all_dependencies_are_recorded(bool on) { 213 _all_dependencies_are_recorded = (on != 0); 214 } 215 216 217 // let JVMTI know that the JVM_OnLoad code is running 218 static void enter_onload_phase() NOT_JVMTI_RETURN; 219 220 // let JVMTI know that the VM isn't up yet (and JVM_OnLoad code isn't running) 221 static void enter_primordial_phase() NOT_JVMTI_RETURN; 222 223 // let JVMTI know that the VM isn't up yet but JNI is live 224 static void enter_start_phase() NOT_JVMTI_RETURN; 225 226 // let JVMTI know that the VM is fully up and running now 227 static void enter_live_phase() NOT_JVMTI_RETURN; 228 229 // ------ can_* conditions (below) are set at OnLoad and never changed ------------ 230 inline static bool can_modify_any_class() { 231 JVMTI_ONLY(return _can_modify_any_class); 232 NOT_JVMTI(return false); 233 } 234 inline static bool can_access_local_variables() { 235 JVMTI_ONLY(return _can_access_local_variables); 236 NOT_JVMTI(return false); 237 } 238 inline static bool can_hotswap_or_post_breakpoint() { 239 JVMTI_ONLY(return _can_hotswap_or_post_breakpoint); 240 NOT_JVMTI(return false); 241 } 242 inline static bool can_walk_any_space() { 243 JVMTI_ONLY(return _can_walk_any_space); 244 NOT_JVMTI(return false); 245 } 246 247 // field access management 248 static address get_field_access_count_addr() NOT_JVMTI_RETURN_(0); 249 250 // field modification management 251 static address get_field_modification_count_addr() NOT_JVMTI_RETURN_(0); 252 253 // ----------------- 254 255 static bool is_jvmti_version(jint version) { 256 JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMTI_VERSION_VALUE); 257 NOT_JVMTI(return false); 258 } 259 static bool is_jvmdi_version(jint version) { 260 JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMDI_VERSION_VALUE); 261 NOT_JVMTI(return false); 262 } 263 static jint get_jvmti_interface(JavaVM *jvm, void **penv, jint version) NOT_JVMTI_RETURN_(0); 264 static void decode_version_values(jint version, int * major, int * minor, 265 int * micro) NOT_JVMTI_RETURN; 266 267 // single stepping management methods 268 static void at_single_stepping_point(JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN; 269 static void expose_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN; 270 static bool hide_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN_(false); 271 272 // Methods that notify the debugger that something interesting has happened in the VM. 273 static void post_vm_start () NOT_JVMTI_RETURN; 274 static void post_vm_initialized () NOT_JVMTI_RETURN; 275 static void post_vm_death () NOT_JVMTI_RETURN; 276 277 static void post_single_step (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN; 278 static void post_raw_breakpoint (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN; 279 280 static void post_exception_throw (JavaThread *thread, Method* method, address location, oop exception) NOT_JVMTI_RETURN; 281 static void notice_unwind_due_to_exception (JavaThread *thread, Method* method, address location, oop exception, bool in_handler_frame) NOT_JVMTI_RETURN; 282 283 static oop jni_GetField_probe (JavaThread *thread, jobject jobj, 284 oop obj, Klass* klass, jfieldID fieldID, bool is_static) 285 NOT_JVMTI_RETURN_(NULL); 286 static oop jni_GetField_probe_nh (JavaThread *thread, jobject jobj, 287 oop obj, Klass* klass, jfieldID fieldID, bool is_static) 288 NOT_JVMTI_RETURN_(NULL); 289 static void post_field_access_by_jni (JavaThread *thread, oop obj, 290 Klass* klass, jfieldID fieldID, bool is_static) NOT_JVMTI_RETURN; 291 static void post_field_access (JavaThread *thread, Method* method, 292 address location, KlassHandle field_klass, Handle object, jfieldID field) NOT_JVMTI_RETURN; 293 static oop jni_SetField_probe (JavaThread *thread, jobject jobj, 294 oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type, 295 jvalue *value) NOT_JVMTI_RETURN_(NULL); 296 static oop jni_SetField_probe_nh (JavaThread *thread, jobject jobj, 297 oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type, 298 jvalue *value) NOT_JVMTI_RETURN_(NULL); 299 static void post_field_modification_by_jni(JavaThread *thread, oop obj, 300 Klass* klass, jfieldID fieldID, bool is_static, char sig_type, 301 jvalue *value); 302 static void post_raw_field_modification(JavaThread *thread, Method* method, 303 address location, KlassHandle field_klass, Handle object, jfieldID field, 304 char sig_type, jvalue *value) NOT_JVMTI_RETURN; 305 306 static void post_method_entry (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN; 307 static void post_method_exit (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN; 308 309 static void post_class_load (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN; 310 static void post_class_unload (Klass* klass) NOT_JVMTI_RETURN; 311 static void post_class_prepare (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN; 312 313 static void post_thread_start (JavaThread *thread) NOT_JVMTI_RETURN; 314 static void post_thread_end (JavaThread *thread) NOT_JVMTI_RETURN; 315 316 // Support for java.lang.instrument agent loading. 317 static bool _should_post_class_file_load_hook; 318 inline static void set_should_post_class_file_load_hook(bool on) { _should_post_class_file_load_hook = on; } 319 inline static bool should_post_class_file_load_hook() { 320 JVMTI_ONLY(return _should_post_class_file_load_hook); 321 NOT_JVMTI(return false;) 322 } 323 static void post_class_file_load_hook(Symbol* h_name, Handle class_loader, 324 Handle h_protection_domain, 325 unsigned char **data_ptr, unsigned char **end_ptr, 326 JvmtiCachedClassFileData **cache_ptr) NOT_JVMTI_RETURN; 327 static void post_native_method_bind(Method* method, address* function_ptr) NOT_JVMTI_RETURN; 328 static void post_compiled_method_load(nmethod *nm) NOT_JVMTI_RETURN; 329 static void post_dynamic_code_generated(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN; 330 331 // used to post a CompiledMethodUnload event 332 static void post_compiled_method_unload(jmethodID mid, const void *code_begin) NOT_JVMTI_RETURN; 333 334 // similiar to post_dynamic_code_generated except that it can be used to 335 // post a DynamicCodeGenerated event while holding locks in the VM. Any event 336 // posted using this function is recorded by the enclosing event collector 337 // -- JvmtiDynamicCodeEventCollector. 338 static void post_dynamic_code_generated_while_holding_locks(const char* name, address code_begin, address code_end) NOT_JVMTI_RETURN; 339 340 static void post_garbage_collection_finish() NOT_JVMTI_RETURN; 341 static void post_garbage_collection_start() NOT_JVMTI_RETURN; 342 static void post_data_dump() NOT_JVMTI_RETURN; 343 static void post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN; 344 static void post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN; 345 static void post_monitor_wait(JavaThread *thread, oop obj, jlong timeout) NOT_JVMTI_RETURN; 346 static void post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) NOT_JVMTI_RETURN; 347 static void post_object_free(JvmtiEnv* env, jlong tag) NOT_JVMTI_RETURN; 348 static void post_resource_exhausted(jint resource_exhausted_flags, const char* detail) NOT_JVMTI_RETURN; 349 static void record_vm_internal_object_allocation(oop object) NOT_JVMTI_RETURN; 350 // Post objects collected by vm_object_alloc_event_collector. 351 static void post_vm_object_alloc(JavaThread *thread, oop object) NOT_JVMTI_RETURN; 352 // Collects vm internal objects for later event posting. 353 inline static void vm_object_alloc_event_collector(oop object) { 354 if (should_post_vm_object_alloc()) { 355 record_vm_internal_object_allocation(object); 356 } 357 } 358 inline static void post_array_size_exhausted() { 359 if (should_post_resource_exhausted()) { 360 post_resource_exhausted(JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR, 361 "Requested array size exceeds VM limit"); 362 } 363 } 364 365 static void cleanup_thread (JavaThread* thread) NOT_JVMTI_RETURN; 366 static void clear_detected_exception (JavaThread* thread) NOT_JVMTI_RETURN; 367 368 static void oops_do(OopClosure* f) NOT_JVMTI_RETURN; 369 static void weak_oops_do(BoolObjectClosure* b, OopClosure* f) NOT_JVMTI_RETURN; 370 static void gc_epilogue() NOT_JVMTI_RETURN; 371 372 static void transition_pending_onload_raw_monitors() NOT_JVMTI_RETURN; 373 374 // attach support 375 static jint load_agent_library(const char *agent, const char *absParam, const char *options, outputStream* out) NOT_JVMTI_RETURN_(JNI_ERR); 376 static jint load_agent_library(AttachOperation* op, outputStream* out) NOT_JVMTI_RETURN_(JNI_ERR); 377 378 // SetNativeMethodPrefix support 379 static char** get_all_native_method_prefixes(int* count_ptr) NOT_JVMTI_RETURN_(NULL); 380 }; 381 382 // Support class used by JvmtiDynamicCodeEventCollector and others. It 383 // describes a single code blob by name and address range. 384 class JvmtiCodeBlobDesc : public CHeapObj<mtInternal> { 385 private: 386 char _name[64]; 387 address _code_begin; 388 address _code_end; 389 390 public: 391 JvmtiCodeBlobDesc(const char *name, address code_begin, address code_end) { 392 assert(name != NULL, "all code blobs must be named"); 393 strncpy(_name, name, sizeof(_name)); 394 _name[sizeof(_name)-1] = '\0'; 395 _code_begin = code_begin; 396 _code_end = code_end; 397 } 398 char* name() { return _name; } 399 address code_begin() { return _code_begin; } 400 address code_end() { return _code_end; } 401 }; 402 403 // JvmtiEventCollector is a helper class to setup thread for 404 // event collection. 405 class JvmtiEventCollector : public StackObj { 406 private: 407 JvmtiEventCollector* _prev; // Save previous one to support nested event collector. 408 409 public: 410 void setup_jvmti_thread_state(); // Set this collector in current thread. 411 void unset_jvmti_thread_state(); // Reset previous collector in current thread. 412 virtual bool is_dynamic_code_event() { return false; } 413 virtual bool is_vm_object_alloc_event(){ return false; } 414 JvmtiEventCollector *get_prev() { return _prev; } 415 }; 416 417 // A JvmtiDynamicCodeEventCollector is a helper class for the JvmtiExport 418 // interface. It collects "dynamic code generated" events that are posted 419 // while holding locks. When the event collector goes out of scope the 420 // events will be posted. 421 // 422 // Usage :- 423 // 424 // { 425 // JvmtiDynamicCodeEventCollector event_collector; 426 // : 427 // { MutexLocker ml(...) 428 // : 429 // JvmtiExport::post_dynamic_code_generated_while_holding_locks(...) 430 // } 431 // // event collector goes out of scope => post events to profiler. 432 // } 433 434 class JvmtiDynamicCodeEventCollector : public JvmtiEventCollector { 435 private: 436 GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs; // collected code blob events 437 438 friend class JvmtiExport; 439 void register_stub(const char* name, address start, address end); 440 441 public: 442 JvmtiDynamicCodeEventCollector() NOT_JVMTI_RETURN; 443 ~JvmtiDynamicCodeEventCollector() NOT_JVMTI_RETURN; 444 bool is_dynamic_code_event() { return true; } 445 446 }; 447 448 // Used to record vm internally allocated object oops and post 449 // vm object alloc event for objects visible to java world. 450 // Constructor enables JvmtiThreadState flag and all vm allocated 451 // objects are recorded in a growable array. When destructor is 452 // called the vm object alloc event is posted for each objects 453 // visible to java world. 454 // See jvm.cpp file for its usage. 455 // 456 class JvmtiVMObjectAllocEventCollector : public JvmtiEventCollector { 457 private: 458 GrowableArray<oop>* _allocated; // field to record vm internally allocated object oop. 459 bool _enable; // This flag is enabled in constructor and disabled 460 // in destructor before posting event. To avoid 461 // collection of objects allocated while running java code inside 462 // agent post_vm_object_alloc() event handler. 463 464 //GC support 465 void oops_do(OopClosure* f); 466 467 friend class JvmtiExport; 468 // Record vm allocated object oop. 469 inline void record_allocation(oop obj); 470 471 //GC support 472 static void oops_do_for_all_threads(OopClosure* f); 473 474 public: 475 JvmtiVMObjectAllocEventCollector() NOT_JVMTI_RETURN; 476 ~JvmtiVMObjectAllocEventCollector() NOT_JVMTI_RETURN; 477 bool is_vm_object_alloc_event() { return true; } 478 479 bool is_enabled() { return _enable; } 480 void set_enabled(bool on) { _enable = on; } 481 }; 482 483 484 485 // Marker class to disable the posting of VMObjectAlloc events 486 // within its scope. 487 // 488 // Usage :- 489 // 490 // { 491 // NoJvmtiVMObjectAllocMark njm; 492 // : 493 // // VMObjAlloc event will not be posted 494 // JvmtiExport::vm_object_alloc_event_collector(obj); 495 // : 496 // } 497 498 class NoJvmtiVMObjectAllocMark : public StackObj { 499 private: 500 // enclosing collector if enabled, NULL otherwise 501 JvmtiVMObjectAllocEventCollector *_collector; 502 503 bool was_enabled() { return _collector != NULL; } 504 505 public: 506 NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN; 507 ~NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN; 508 }; 509 510 511 // Base class for reporting GC events to JVMTI. 512 class JvmtiGCMarker : public StackObj { 513 public: 514 JvmtiGCMarker() NOT_JVMTI_RETURN; 515 ~JvmtiGCMarker() NOT_JVMTI_RETURN; 516 }; 517 518 // JvmtiHideSingleStepping is a helper class for hiding 519 // internal single step events. 520 class JvmtiHideSingleStepping : public StackObj { 521 private: 522 bool _single_step_hidden; 523 JavaThread * _thread; 524 525 public: 526 JvmtiHideSingleStepping(JavaThread * thread) { 527 assert(thread != NULL, "sanity check"); 528 529 _single_step_hidden = false; 530 _thread = thread; 531 if (JvmtiExport::should_post_single_step()) { 532 _single_step_hidden = JvmtiExport::hide_single_stepping(_thread); 533 } 534 } 535 536 ~JvmtiHideSingleStepping() { 537 if (_single_step_hidden) { 538 JvmtiExport::expose_single_stepping(_thread); 539 } 540 } 541 }; 542 543 #endif // SHARE_VM_PRIMS_JVMTIEXPORT_HPP