1 /* 2 * Copyright (c) 1998, 2016, 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 JVMTI_SUPPORT_FLAG(early_vmstart_recorded) 95 96 friend class JvmtiEventControllerPrivate; // should only modify these flags 97 JVMTI_SUPPORT_FLAG(should_post_single_step) 98 JVMTI_SUPPORT_FLAG(should_post_field_access) 99 JVMTI_SUPPORT_FLAG(should_post_field_modification) 100 JVMTI_SUPPORT_FLAG(should_post_class_load) 101 JVMTI_SUPPORT_FLAG(should_post_class_prepare) 102 JVMTI_SUPPORT_FLAG(should_post_class_unload) 103 JVMTI_SUPPORT_FLAG(should_post_native_method_bind) 104 JVMTI_SUPPORT_FLAG(should_post_compiled_method_load) 105 JVMTI_SUPPORT_FLAG(should_post_compiled_method_unload) 106 JVMTI_SUPPORT_FLAG(should_post_dynamic_code_generated) 107 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_enter) 108 JVMTI_SUPPORT_FLAG(should_post_monitor_contended_entered) 109 JVMTI_SUPPORT_FLAG(should_post_monitor_wait) 110 JVMTI_SUPPORT_FLAG(should_post_monitor_waited) 111 JVMTI_SUPPORT_FLAG(should_post_data_dump) 112 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start) 113 JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish) 114 JVMTI_SUPPORT_FLAG(should_post_on_exceptions) 115 116 // ------ the below maybe don't have to be (but are for now) 117 // fixed conditions here ------------ 118 // any events can be enabled 119 JVMTI_SUPPORT_FLAG(should_post_thread_life) 120 JVMTI_SUPPORT_FLAG(should_post_object_free) 121 JVMTI_SUPPORT_FLAG(should_post_resource_exhausted) 122 123 // we are holding objects on the heap - need to talk to GC - e.g. 124 // breakpoint info 125 JVMTI_SUPPORT_FLAG(should_clean_up_heap_objects) 126 JVMTI_SUPPORT_FLAG(should_post_vm_object_alloc) 127 128 // If flag cannot be implemented, give an error if on=true 129 static void report_unsupported(bool on); 130 131 // these should only be called by the friend class 132 friend class JvmtiManageCapabilities; 133 inline static void set_can_modify_any_class(bool on) { 134 JVMTI_ONLY(_can_modify_any_class = (on != 0);) 135 } 136 inline static void set_can_access_local_variables(bool on) { 137 JVMTI_ONLY(_can_access_local_variables = (on != 0);) 138 } 139 inline static void set_can_hotswap_or_post_breakpoint(bool on) { 140 JVMTI_ONLY(_can_hotswap_or_post_breakpoint = (on != 0);) 141 } 142 inline static void set_can_walk_any_space(bool on) { 143 JVMTI_ONLY(_can_walk_any_space = (on != 0);) 144 } 145 146 enum { 147 JVMTI_VERSION_MASK = 0x70000000, 148 JVMTI_VERSION_VALUE = 0x30000000, 149 JVMDI_VERSION_VALUE = 0x20000000 150 }; 151 152 static void post_field_modification(JavaThread *thread, Method* method, address location, 153 KlassHandle field_klass, Handle object, jfieldID field, 154 char sig_type, jvalue *value); 155 156 157 // posts a DynamicCodeGenerated event (internal/private implementation). 158 // The public post_dynamic_code_generated* functions make use of the 159 // internal implementation. Also called from JvmtiDeferredEvent::post() 160 static void post_dynamic_code_generated_internal(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN; 161 162 private: 163 164 // GenerateEvents support to allow posting of CompiledMethodLoad and 165 // DynamicCodeGenerated events for a given environment. 166 friend class JvmtiCodeBlobEvents; 167 168 static void post_compiled_method_load(JvmtiEnv* env, const jmethodID method, const jint length, 169 const void *code_begin, const jint map_length, 170 const jvmtiAddrLocationMap* map) NOT_JVMTI_RETURN; 171 static void post_dynamic_code_generated(JvmtiEnv* env, const char *name, const void *code_begin, 172 const void *code_end) NOT_JVMTI_RETURN; 173 174 // The RedefineClasses() API breaks some invariants in the "regular" 175 // system. For example, there are sanity checks when GC'ing nmethods 176 // that require the containing class to be unloading. However, when a 177 // method is redefined, the old method and nmethod can become GC'able 178 // without the containing class unloading. The state of becoming 179 // GC'able can be asynchronous to the RedefineClasses() call since 180 // the old method may still be running and cannot be GC'ed until 181 // after all old invocations have finished. Additionally, a method 182 // that has not been redefined may have an nmethod that depends on 183 // the redefined method. The dependent nmethod will get deopted in 184 // this case and may also be GC'able without the containing class 185 // being unloaded. 186 // 187 // This flag indicates whether RedefineClasses() has ever redefined 188 // one or more classes during the lifetime of the VM. The flag should 189 // only be set by the friend class and can be queried by other sub 190 // systems as needed to relax invariant checks. 191 static bool _has_redefined_a_class; 192 friend class VM_RedefineClasses; 193 inline static void set_has_redefined_a_class() { 194 JVMTI_ONLY(_has_redefined_a_class = true;) 195 } 196 // Flag to indicate if the compiler has recorded all dependencies. When the 197 // can_redefine_classes capability is enabled in the OnLoad phase then the compiler 198 // records all dependencies from startup. However if the capability is first 199 // enabled some time later then the dependencies recorded by the compiler 200 // are incomplete. This flag is used by RedefineClasses to know if the 201 // dependency information is complete or not. 202 static bool _all_dependencies_are_recorded; 203 204 public: 205 inline static bool has_redefined_a_class() { 206 JVMTI_ONLY(return _has_redefined_a_class); 207 NOT_JVMTI(return false); 208 } 209 210 inline static bool all_dependencies_are_recorded() { 211 return _all_dependencies_are_recorded; 212 } 213 214 inline static void set_all_dependencies_are_recorded(bool on) { 215 _all_dependencies_are_recorded = (on != 0); 216 } 217 218 // Add read edges to the unnamed modules of the bootstrap and app class loaders 219 static void add_default_read_edges(Handle h_module, TRAPS) NOT_JVMTI_RETURN; 220 221 // let JVMTI know that the JVM_OnLoad code is running 222 static void enter_onload_phase() NOT_JVMTI_RETURN; 223 224 // let JVMTI know that the VM isn't up yet (and JVM_OnLoad code isn't running) 225 static void enter_primordial_phase() NOT_JVMTI_RETURN; 226 227 // let JVMTI know that the VM isn't up yet but JNI is live 228 static void enter_early_start_phase() NOT_JVMTI_RETURN; 229 static void enter_start_phase() NOT_JVMTI_RETURN; 230 231 // let JVMTI know that the VM is fully up and running now 232 static void enter_live_phase() NOT_JVMTI_RETURN; 233 234 // ------ can_* conditions (below) are set at OnLoad and never changed ------------ 235 inline static bool can_modify_any_class() { 236 JVMTI_ONLY(return _can_modify_any_class); 237 NOT_JVMTI(return false); 238 } 239 inline static bool can_access_local_variables() { 240 JVMTI_ONLY(return _can_access_local_variables); 241 NOT_JVMTI(return false); 242 } 243 inline static bool can_hotswap_or_post_breakpoint() { 244 JVMTI_ONLY(return _can_hotswap_or_post_breakpoint); 245 NOT_JVMTI(return false); 246 } 247 inline static bool can_walk_any_space() { 248 JVMTI_ONLY(return _can_walk_any_space); 249 NOT_JVMTI(return false); 250 } 251 252 // field access management 253 static address get_field_access_count_addr() NOT_JVMTI_RETURN_(0); 254 255 // field modification management 256 static address get_field_modification_count_addr() NOT_JVMTI_RETURN_(0); 257 258 // ----------------- 259 260 static bool is_jvmti_version(jint version) { 261 JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMTI_VERSION_VALUE); 262 NOT_JVMTI(return false); 263 } 264 static bool is_jvmdi_version(jint version) { 265 JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMDI_VERSION_VALUE); 266 NOT_JVMTI(return false); 267 } 268 static jint get_jvmti_interface(JavaVM *jvm, void **penv, jint version) NOT_JVMTI_RETURN_(0); 269 static void decode_version_values(jint version, int * major, int * minor, 270 int * micro) NOT_JVMTI_RETURN; 271 272 // single stepping management methods 273 static void at_single_stepping_point(JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN; 274 static void expose_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN; 275 static bool hide_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN_(false); 276 277 // Methods that notify the debugger that something interesting has happened in the VM. 278 static void post_early_vm_start () NOT_JVMTI_RETURN; 279 static void post_vm_start () NOT_JVMTI_RETURN; 280 static void post_vm_initialized () NOT_JVMTI_RETURN; 281 static void post_vm_death () NOT_JVMTI_RETURN; 282 283 static void post_single_step (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN; 284 static void post_raw_breakpoint (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN; 285 286 static void post_exception_throw (JavaThread *thread, Method* method, address location, oop exception) NOT_JVMTI_RETURN; 287 static void notice_unwind_due_to_exception (JavaThread *thread, Method* method, address location, oop exception, bool in_handler_frame) NOT_JVMTI_RETURN; 288 289 static oop jni_GetField_probe (JavaThread *thread, jobject jobj, 290 oop obj, Klass* klass, jfieldID fieldID, bool is_static) 291 NOT_JVMTI_RETURN_(NULL); 292 static oop jni_GetField_probe_nh (JavaThread *thread, jobject jobj, 293 oop obj, Klass* klass, jfieldID fieldID, bool is_static) 294 NOT_JVMTI_RETURN_(NULL); 295 static void post_field_access_by_jni (JavaThread *thread, oop obj, 296 Klass* klass, jfieldID fieldID, bool is_static) NOT_JVMTI_RETURN; 297 static void post_field_access (JavaThread *thread, Method* method, 298 address location, KlassHandle field_klass, Handle object, jfieldID field) NOT_JVMTI_RETURN; 299 static oop jni_SetField_probe (JavaThread *thread, jobject jobj, 300 oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type, 301 jvalue *value) NOT_JVMTI_RETURN_(NULL); 302 static oop jni_SetField_probe_nh (JavaThread *thread, jobject jobj, 303 oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type, 304 jvalue *value) NOT_JVMTI_RETURN_(NULL); 305 static void post_field_modification_by_jni(JavaThread *thread, oop obj, 306 Klass* klass, jfieldID fieldID, bool is_static, char sig_type, 307 jvalue *value); 308 static void post_raw_field_modification(JavaThread *thread, Method* method, 309 address location, KlassHandle field_klass, Handle object, jfieldID field, 310 char sig_type, jvalue *value) NOT_JVMTI_RETURN; 311 312 static void post_method_entry (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN; 313 static void post_method_exit (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN; 314 315 static void post_class_load (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN; 316 static void post_class_unload (Klass* klass) NOT_JVMTI_RETURN; 317 static void post_class_prepare (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN; 318 319 static void post_thread_start (JavaThread *thread) NOT_JVMTI_RETURN; 320 static void post_thread_end (JavaThread *thread) NOT_JVMTI_RETURN; 321 322 // Support for java.lang.instrument agent loading. 323 static bool _should_post_class_file_load_hook; 324 inline static void set_should_post_class_file_load_hook(bool on) { _should_post_class_file_load_hook = on; } 325 inline static bool should_post_class_file_load_hook() { 326 JVMTI_ONLY(return _should_post_class_file_load_hook); 327 NOT_JVMTI(return false;) 328 } 329 static void post_class_file_load_hook(Symbol* h_name, Handle class_loader, 330 Handle h_protection_domain, 331 unsigned char **data_ptr, unsigned char **end_ptr, 332 JvmtiCachedClassFileData **cache_ptr) NOT_JVMTI_RETURN; 333 static void post_native_method_bind(Method* method, address* function_ptr) NOT_JVMTI_RETURN; 334 static void post_compiled_method_load(nmethod *nm) NOT_JVMTI_RETURN; 335 static void post_dynamic_code_generated(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN; 336 337 // used to post a CompiledMethodUnload event 338 static void post_compiled_method_unload(jmethodID mid, const void *code_begin) NOT_JVMTI_RETURN; 339 340 // similiar to post_dynamic_code_generated except that it can be used to 341 // post a DynamicCodeGenerated event while holding locks in the VM. Any event 342 // posted using this function is recorded by the enclosing event collector 343 // -- JvmtiDynamicCodeEventCollector. 344 static void post_dynamic_code_generated_while_holding_locks(const char* name, address code_begin, address code_end) NOT_JVMTI_RETURN; 345 346 static void post_garbage_collection_finish() NOT_JVMTI_RETURN; 347 static void post_garbage_collection_start() NOT_JVMTI_RETURN; 348 static void post_data_dump() NOT_JVMTI_RETURN; 349 static void post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN; 350 static void post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN; 351 static void post_monitor_wait(JavaThread *thread, oop obj, jlong timeout) NOT_JVMTI_RETURN; 352 static void post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) NOT_JVMTI_RETURN; 353 static void post_object_free(JvmtiEnv* env, jlong tag) NOT_JVMTI_RETURN; 354 static void post_resource_exhausted(jint resource_exhausted_flags, const char* detail) NOT_JVMTI_RETURN; 355 static void record_vm_internal_object_allocation(oop object) NOT_JVMTI_RETURN; 356 // Post objects collected by vm_object_alloc_event_collector. 357 static void post_vm_object_alloc(JavaThread *thread, oop object) NOT_JVMTI_RETURN; 358 // Collects vm internal objects for later event posting. 359 inline static void vm_object_alloc_event_collector(oop object) { 360 if (should_post_vm_object_alloc()) { 361 record_vm_internal_object_allocation(object); 362 } 363 } 364 inline static void post_array_size_exhausted() { 365 if (should_post_resource_exhausted()) { 366 post_resource_exhausted(JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR, 367 "Requested array size exceeds VM limit"); 368 } 369 } 370 371 static void cleanup_thread (JavaThread* thread) NOT_JVMTI_RETURN; 372 static void clear_detected_exception (JavaThread* thread) NOT_JVMTI_RETURN; 373 374 static void oops_do(OopClosure* f) NOT_JVMTI_RETURN; 375 static void weak_oops_do(BoolObjectClosure* b, OopClosure* f) NOT_JVMTI_RETURN; 376 static void gc_epilogue() NOT_JVMTI_RETURN; 377 378 static void transition_pending_onload_raw_monitors() NOT_JVMTI_RETURN; 379 380 #if INCLUDE_SERVICES 381 // attach support 382 static jint load_agent_library(const char *agent, const char *absParam, const char *options, outputStream* out) NOT_JVMTI_RETURN_(JNI_ERR); 383 static jint load_agent_library(AttachOperation* op, outputStream* out) NOT_JVMTI_RETURN_(JNI_ERR); 384 #endif 385 386 // SetNativeMethodPrefix support 387 static char** get_all_native_method_prefixes(int* count_ptr) NOT_JVMTI_RETURN_(NULL); 388 }; 389 390 // Support class used by JvmtiDynamicCodeEventCollector and others. It 391 // describes a single code blob by name and address range. 392 class JvmtiCodeBlobDesc : public CHeapObj<mtInternal> { 393 private: 394 char _name[64]; 395 address _code_begin; 396 address _code_end; 397 398 public: 399 JvmtiCodeBlobDesc(const char *name, address code_begin, address code_end) { 400 assert(name != NULL, "all code blobs must be named"); 401 strncpy(_name, name, sizeof(_name)); 402 _name[sizeof(_name)-1] = '\0'; 403 _code_begin = code_begin; 404 _code_end = code_end; 405 } 406 char* name() { return _name; } 407 address code_begin() { return _code_begin; } 408 address code_end() { return _code_end; } 409 }; 410 411 // JvmtiEventCollector is a helper class to setup thread for 412 // event collection. 413 class JvmtiEventCollector : public StackObj { 414 private: 415 JvmtiEventCollector* _prev; // Save previous one to support nested event collector. 416 417 public: 418 void setup_jvmti_thread_state(); // Set this collector in current thread. 419 void unset_jvmti_thread_state(); // Reset previous collector in current thread. 420 virtual bool is_dynamic_code_event() { return false; } 421 virtual bool is_vm_object_alloc_event(){ return false; } 422 JvmtiEventCollector *get_prev() { return _prev; } 423 }; 424 425 // A JvmtiDynamicCodeEventCollector is a helper class for the JvmtiExport 426 // interface. It collects "dynamic code generated" events that are posted 427 // while holding locks. When the event collector goes out of scope the 428 // events will be posted. 429 // 430 // Usage :- 431 // 432 // { 433 // JvmtiDynamicCodeEventCollector event_collector; 434 // : 435 // { MutexLocker ml(...) 436 // : 437 // JvmtiExport::post_dynamic_code_generated_while_holding_locks(...) 438 // } 439 // // event collector goes out of scope => post events to profiler. 440 // } 441 442 class JvmtiDynamicCodeEventCollector : public JvmtiEventCollector { 443 private: 444 GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs; // collected code blob events 445 446 friend class JvmtiExport; 447 void register_stub(const char* name, address start, address end); 448 449 public: 450 JvmtiDynamicCodeEventCollector() NOT_JVMTI_RETURN; 451 ~JvmtiDynamicCodeEventCollector() NOT_JVMTI_RETURN; 452 bool is_dynamic_code_event() { return true; } 453 454 }; 455 456 // Used to record vm internally allocated object oops and post 457 // vm object alloc event for objects visible to java world. 458 // Constructor enables JvmtiThreadState flag and all vm allocated 459 // objects are recorded in a growable array. When destructor is 460 // called the vm object alloc event is posted for each objects 461 // visible to java world. 462 // See jvm.cpp file for its usage. 463 // 464 class JvmtiVMObjectAllocEventCollector : public JvmtiEventCollector { 465 private: 466 GrowableArray<oop>* _allocated; // field to record vm internally allocated object oop. 467 bool _enable; // This flag is enabled in constructor and disabled 468 // in destructor before posting event. To avoid 469 // collection of objects allocated while running java code inside 470 // agent post_vm_object_alloc() event handler. 471 472 //GC support 473 void oops_do(OopClosure* f); 474 475 friend class JvmtiExport; 476 // Record vm allocated object oop. 477 inline void record_allocation(oop obj); 478 479 //GC support 480 static void oops_do_for_all_threads(OopClosure* f); 481 482 public: 483 JvmtiVMObjectAllocEventCollector() NOT_JVMTI_RETURN; 484 ~JvmtiVMObjectAllocEventCollector() NOT_JVMTI_RETURN; 485 bool is_vm_object_alloc_event() { return true; } 486 487 bool is_enabled() { return _enable; } 488 void set_enabled(bool on) { _enable = on; } 489 }; 490 491 492 493 // Marker class to disable the posting of VMObjectAlloc events 494 // within its scope. 495 // 496 // Usage :- 497 // 498 // { 499 // NoJvmtiVMObjectAllocMark njm; 500 // : 501 // // VMObjAlloc event will not be posted 502 // JvmtiExport::vm_object_alloc_event_collector(obj); 503 // : 504 // } 505 506 class NoJvmtiVMObjectAllocMark : public StackObj { 507 private: 508 // enclosing collector if enabled, NULL otherwise 509 JvmtiVMObjectAllocEventCollector *_collector; 510 511 bool was_enabled() { return _collector != NULL; } 512 513 public: 514 NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN; 515 ~NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN; 516 }; 517 518 519 // Base class for reporting GC events to JVMTI. 520 class JvmtiGCMarker : public StackObj { 521 public: 522 JvmtiGCMarker() NOT_JVMTI_RETURN; 523 ~JvmtiGCMarker() NOT_JVMTI_RETURN; 524 }; 525 526 // JvmtiHideSingleStepping is a helper class for hiding 527 // internal single step events. 528 class JvmtiHideSingleStepping : public StackObj { 529 private: 530 bool _single_step_hidden; 531 JavaThread * _thread; 532 533 public: 534 JvmtiHideSingleStepping(JavaThread * thread) { 535 assert(thread != NULL, "sanity check"); 536 537 _single_step_hidden = false; 538 _thread = thread; 539 if (JvmtiExport::should_post_single_step()) { 540 _single_step_hidden = JvmtiExport::hide_single_stepping(_thread); 541 } 542 } 543 544 ~JvmtiHideSingleStepping() { 545 if (_single_step_hidden) { 546 JvmtiExport::expose_single_stepping(_thread); 547 } 548 } 549 }; 550 551 #endif // SHARE_VM_PRIMS_JVMTIEXPORT_HPP