1 /*
   2  * Copyright (c) 1998, 2018, 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 "jvmticmlr.h"
  41 
  42 // Forward declarations
  43 
  44 class JvmtiEventControllerPrivate;
  45 class JvmtiManageCapabilities;
  46 class JvmtiEnv;
  47 class JvmtiThreadState;
  48 
  49 #define JVMTI_SUPPORT_FLAG(key)                                           \
  50   private:                                                                \
  51   static bool  _##key;                                                    \
  52   public:                                                                 \
  53   inline static void set_##key(bool on) {                                 \
  54     JVMTI_ONLY(_##key = (on != 0));                                       \
  55     NOT_JVMTI(report_unsupported(on));                                    \
  56   }                                                                       \
  57   inline static bool key() {                                              \
  58     JVMTI_ONLY(return _##key);                                            \
  59     NOT_JVMTI(return false);                                              \
  60   }
  61 
  62 
  63 // This class contains the JVMTI interface for the rest of hotspot.
  64 //
  65 class JvmtiExport : public AllStatic {
  66   friend class VMStructs;
  67   friend class CompileReplay;
  68 
  69  private:
  70 
  71 #if INCLUDE_JVMTI
  72   static int         _field_access_count;
  73   static int         _field_modification_count;
  74 
  75   static bool        _can_access_local_variables;
  76   static bool        _can_hotswap_or_post_breakpoint;
  77   static bool        _can_modify_any_class;
  78   static bool        _can_walk_any_space;
  79 #endif // INCLUDE_JVMTI
  80 
  81   JVMTI_SUPPORT_FLAG(can_get_source_debug_extension)
  82   JVMTI_SUPPORT_FLAG(can_maintain_original_method_order)
  83   JVMTI_SUPPORT_FLAG(can_post_interpreter_events)
  84   JVMTI_SUPPORT_FLAG(can_post_on_exceptions)
  85   JVMTI_SUPPORT_FLAG(can_post_breakpoint)
  86   JVMTI_SUPPORT_FLAG(can_post_field_access)
  87   JVMTI_SUPPORT_FLAG(can_post_field_modification)
  88   JVMTI_SUPPORT_FLAG(can_post_method_entry)
  89   JVMTI_SUPPORT_FLAG(can_post_method_exit)
  90   JVMTI_SUPPORT_FLAG(can_pop_frame)
  91   JVMTI_SUPPORT_FLAG(can_force_early_return)
  92 
  93   JVMTI_SUPPORT_FLAG(early_vmstart_recorded)
  94 
  95   friend class JvmtiEventControllerPrivate;  // should only modify these flags
  96   JVMTI_SUPPORT_FLAG(should_post_single_step)
  97   JVMTI_SUPPORT_FLAG(should_post_field_access)
  98   JVMTI_SUPPORT_FLAG(should_post_field_modification)
  99   JVMTI_SUPPORT_FLAG(should_post_class_load)
 100   JVMTI_SUPPORT_FLAG(should_post_class_prepare)
 101   JVMTI_SUPPORT_FLAG(should_post_class_unload)
 102   JVMTI_SUPPORT_FLAG(should_post_native_method_bind)
 103   JVMTI_SUPPORT_FLAG(should_post_compiled_method_load)
 104   JVMTI_SUPPORT_FLAG(should_post_compiled_method_unload)
 105   JVMTI_SUPPORT_FLAG(should_post_dynamic_code_generated)
 106   JVMTI_SUPPORT_FLAG(should_post_monitor_contended_enter)
 107   JVMTI_SUPPORT_FLAG(should_post_monitor_contended_entered)
 108   JVMTI_SUPPORT_FLAG(should_post_monitor_wait)
 109   JVMTI_SUPPORT_FLAG(should_post_monitor_waited)
 110   JVMTI_SUPPORT_FLAG(should_post_data_dump)
 111   JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start)
 112   JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish)
 113   JVMTI_SUPPORT_FLAG(should_post_on_exceptions)
 114 
 115   // ------ the below maybe don't have to be (but are for now)
 116   // fixed conditions here ------------
 117   // any events can be enabled
 118   JVMTI_SUPPORT_FLAG(should_post_thread_life)
 119   JVMTI_SUPPORT_FLAG(should_post_object_free)
 120   JVMTI_SUPPORT_FLAG(should_post_resource_exhausted)
 121 
 122   // we are holding objects on the heap - need to talk to GC - e.g.
 123   // breakpoint info
 124   JVMTI_SUPPORT_FLAG(should_clean_up_heap_objects)
 125   JVMTI_SUPPORT_FLAG(should_post_vm_object_alloc)
 126 
 127   // If flag cannot be implemented, give an error if on=true
 128   static void report_unsupported(bool on);
 129 
 130   // these should only be called by the friend class
 131   friend class JvmtiManageCapabilities;
 132   inline static void set_can_modify_any_class(bool on) {
 133     JVMTI_ONLY(_can_modify_any_class = (on != 0);)
 134   }
 135   inline static void set_can_access_local_variables(bool on) {
 136     JVMTI_ONLY(_can_access_local_variables = (on != 0);)
 137   }
 138   inline static void set_can_hotswap_or_post_breakpoint(bool on) {
 139     JVMTI_ONLY(_can_hotswap_or_post_breakpoint = (on != 0);)
 140   }
 141   inline static void set_can_walk_any_space(bool on) {
 142     JVMTI_ONLY(_can_walk_any_space = (on != 0);)
 143   }
 144 
 145   enum {
 146     JVMTI_VERSION_MASK   = 0x70000000,
 147     JVMTI_VERSION_VALUE  = 0x30000000,
 148     JVMDI_VERSION_VALUE  = 0x20000000
 149   };
 150 
 151   static void post_field_modification(JavaThread *thread, Method* method, address location,
 152                                       Klass* field_klass, Handle object, jfieldID field,
 153                                       char sig_type, jvalue *value);
 154 
 155 
 156   // posts a DynamicCodeGenerated event (internal/private implementation).
 157   // The public post_dynamic_code_generated* functions make use of the
 158   // internal implementation.  Also called from JvmtiDeferredEvent::post()
 159   static void post_dynamic_code_generated_internal(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN;
 160 
 161  private:
 162 
 163   // GenerateEvents support to allow posting of CompiledMethodLoad and
 164   // DynamicCodeGenerated events for a given environment.
 165   friend class JvmtiCodeBlobEvents;
 166 
 167   static void post_compiled_method_load(JvmtiEnv* env, const jmethodID method, const jint length,
 168                                         const void *code_begin, const jint map_length,
 169                                         const jvmtiAddrLocationMap* map) NOT_JVMTI_RETURN;
 170   static void post_dynamic_code_generated(JvmtiEnv* env, const char *name, const void *code_begin,
 171                                           const void *code_end) NOT_JVMTI_RETURN;
 172 
 173   // This flag indicates whether RedefineClasses() has ever redefined
 174   // one or more classes during the lifetime of the VM. The flag should
 175   // only be set by the friend class and can be queried by other sub
 176   // systems as needed to relax invariant checks.
 177   static bool _has_redefined_a_class;
 178   friend class VM_RedefineClasses;
 179   inline static void set_has_redefined_a_class() {
 180     JVMTI_ONLY(_has_redefined_a_class = true;)
 181   }
 182   // Flag to indicate if the compiler has recorded all dependencies. When the
 183   // can_redefine_classes capability is enabled in the OnLoad phase then the compiler
 184   // records all dependencies from startup. However if the capability is first
 185   // enabled some time later then the dependencies recorded by the compiler
 186   // are incomplete. This flag is used by RedefineClasses to know if the
 187   // dependency information is complete or not.
 188   static bool _all_dependencies_are_recorded;
 189 
 190  public:
 191   inline static bool has_redefined_a_class() {
 192     JVMTI_ONLY(return _has_redefined_a_class);
 193     NOT_JVMTI(return false);
 194   }
 195 
 196   inline static bool all_dependencies_are_recorded() {
 197     return _all_dependencies_are_recorded;
 198   }
 199 
 200   inline static void set_all_dependencies_are_recorded(bool on) {
 201     _all_dependencies_are_recorded = (on != 0);
 202   }
 203 
 204   // Add read edges to the unnamed modules of the bootstrap and app class loaders
 205   static void add_default_read_edges(Handle h_module, TRAPS) NOT_JVMTI_RETURN;
 206 
 207   // Add a read edge to the module
 208   static jvmtiError add_module_reads(Handle module, Handle to_module, TRAPS);
 209 
 210   // Updates a module to export a package
 211   static jvmtiError add_module_exports(Handle module, Handle pkg_name, Handle to_module, TRAPS);
 212 
 213   // Updates a module to open a package
 214   static jvmtiError add_module_opens(Handle module, Handle pkg_name, Handle to_module, TRAPS);
 215 
 216   // Add a used service to the module
 217   static jvmtiError add_module_uses(Handle module, Handle service, TRAPS);
 218 
 219   // Add a service provider to the module
 220   static jvmtiError add_module_provides(Handle module, Handle service, Handle impl_class, TRAPS);
 221 
 222   // let JVMTI know that the JVM_OnLoad code is running
 223   static void enter_onload_phase() NOT_JVMTI_RETURN;
 224 
 225   // let JVMTI know that the VM isn't up yet (and JVM_OnLoad code isn't running)
 226   static void enter_primordial_phase() NOT_JVMTI_RETURN;
 227 
 228   // let JVMTI know that the VM isn't up yet but JNI is live
 229   static void enter_early_start_phase() NOT_JVMTI_RETURN;
 230   static void enter_start_phase() NOT_JVMTI_RETURN;
 231 
 232   // let JVMTI know that the VM is fully up and running now
 233   static void enter_live_phase() NOT_JVMTI_RETURN;
 234 
 235   // ------ can_* conditions (below) are set at OnLoad and never changed ------------
 236   inline static bool can_modify_any_class()                       {
 237     JVMTI_ONLY(return _can_modify_any_class);
 238     NOT_JVMTI(return false);
 239   }
 240   inline static bool can_access_local_variables()                 {
 241     JVMTI_ONLY(return _can_access_local_variables);
 242     NOT_JVMTI(return false);
 243   }
 244   inline static bool can_hotswap_or_post_breakpoint()             {
 245     JVMTI_ONLY(return _can_hotswap_or_post_breakpoint);
 246     NOT_JVMTI(return false);
 247   }
 248   inline static bool can_walk_any_space()                         {
 249     JVMTI_ONLY(return _can_walk_any_space);
 250     NOT_JVMTI(return false);
 251   }
 252 
 253   // field access management
 254   static address  get_field_access_count_addr() NOT_JVMTI_RETURN_(0);
 255 
 256   // field modification management
 257   static address  get_field_modification_count_addr() NOT_JVMTI_RETURN_(0);
 258 
 259   // -----------------
 260 
 261   static bool is_jvmti_version(jint version)                      {
 262     JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMTI_VERSION_VALUE);
 263     NOT_JVMTI(return false);
 264   }
 265   static bool is_jvmdi_version(jint version)                      {
 266     JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMDI_VERSION_VALUE);
 267     NOT_JVMTI(return false);
 268   }
 269   static jint get_jvmti_interface(JavaVM *jvm, void **penv, jint version) NOT_JVMTI_RETURN_(0);
 270   static void decode_version_values(jint version, int * major, int * minor,
 271                                     int * micro) NOT_JVMTI_RETURN;
 272 
 273   // single stepping management methods
 274   static void at_single_stepping_point(JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN;
 275   static void expose_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN;
 276   static bool hide_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN_(false);
 277 
 278   // Methods that notify the debugger that something interesting has happened in the VM.
 279   static void post_early_vm_start        () NOT_JVMTI_RETURN;
 280   static void post_vm_start              () NOT_JVMTI_RETURN;
 281   static void post_vm_initialized        () NOT_JVMTI_RETURN;
 282   static void post_vm_death              () NOT_JVMTI_RETURN;
 283 
 284   static void post_single_step           (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN;
 285   static void post_raw_breakpoint        (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN;
 286 
 287   static void post_exception_throw       (JavaThread *thread, Method* method, address location, oop exception) NOT_JVMTI_RETURN;
 288   static void notice_unwind_due_to_exception (JavaThread *thread, Method* method, address location, oop exception, bool in_handler_frame) NOT_JVMTI_RETURN;
 289 
 290   static oop jni_GetField_probe          (JavaThread *thread, jobject jobj,
 291     oop obj, Klass* klass, jfieldID fieldID, bool is_static)
 292     NOT_JVMTI_RETURN_(NULL);
 293   static oop jni_GetField_probe_nh       (JavaThread *thread, jobject jobj,
 294     oop obj, Klass* klass, jfieldID fieldID, bool is_static)
 295     NOT_JVMTI_RETURN_(NULL);
 296   static void post_field_access_by_jni   (JavaThread *thread, oop obj,
 297     Klass* klass, jfieldID fieldID, bool is_static) NOT_JVMTI_RETURN;
 298   static void post_field_access          (JavaThread *thread, Method* method,
 299     address location, Klass* field_klass, Handle object, jfieldID field) NOT_JVMTI_RETURN;
 300   static oop jni_SetField_probe          (JavaThread *thread, jobject jobj,
 301     oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type,
 302     jvalue *value) NOT_JVMTI_RETURN_(NULL);
 303   static oop jni_SetField_probe_nh       (JavaThread *thread, jobject jobj,
 304     oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type,
 305     jvalue *value) NOT_JVMTI_RETURN_(NULL);
 306   static void post_field_modification_by_jni(JavaThread *thread, oop obj,
 307     Klass* klass, jfieldID fieldID, bool is_static, char sig_type,
 308     jvalue *value);
 309   static void post_raw_field_modification(JavaThread *thread, Method* method,
 310     address location, Klass* field_klass, Handle object, jfieldID field,
 311     char sig_type, jvalue *value) NOT_JVMTI_RETURN;
 312 
 313   static void post_method_entry          (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN;
 314   static void post_method_exit           (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN;
 315 
 316   static void post_class_load            (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN;
 317   static void post_class_unload          (Klass* klass) NOT_JVMTI_RETURN;
 318   static void post_class_prepare         (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN;
 319 
 320   static void post_thread_start          (JavaThread *thread) NOT_JVMTI_RETURN;
 321   static void post_thread_end            (JavaThread *thread) NOT_JVMTI_RETURN;
 322 
 323   // Support for java.lang.instrument agent loading.
 324   static bool _should_post_class_file_load_hook;
 325   inline static void set_should_post_class_file_load_hook(bool on)     { _should_post_class_file_load_hook = on;  }
 326   inline static bool should_post_class_file_load_hook()           {
 327     JVMTI_ONLY(return _should_post_class_file_load_hook);
 328     NOT_JVMTI(return false;)
 329   }
 330   // Return true if the class was modified by the hook.
 331   static bool post_class_file_load_hook(Symbol* h_name, Handle class_loader,
 332                                         Handle h_protection_domain,
 333                                         unsigned char **data_ptr, unsigned char **end_ptr,
 334                                         JvmtiCachedClassFileData **cache_ptr) NOT_JVMTI_RETURN_(false);
 335   static void post_native_method_bind(Method* method, address* function_ptr) NOT_JVMTI_RETURN;
 336   static void post_compiled_method_load(nmethod *nm) NOT_JVMTI_RETURN;
 337   static void post_dynamic_code_generated(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN;
 338 
 339   // used to post a CompiledMethodUnload event
 340   static void post_compiled_method_unload(jmethodID mid, const void *code_begin) NOT_JVMTI_RETURN;
 341 
 342   // similiar to post_dynamic_code_generated except that it can be used to
 343   // post a DynamicCodeGenerated event while holding locks in the VM. Any event
 344   // posted using this function is recorded by the enclosing event collector
 345   // -- JvmtiDynamicCodeEventCollector.
 346   static void post_dynamic_code_generated_while_holding_locks(const char* name, address code_begin, address code_end) NOT_JVMTI_RETURN;
 347 
 348   static void post_garbage_collection_finish() NOT_JVMTI_RETURN;
 349   static void post_garbage_collection_start() NOT_JVMTI_RETURN;
 350   static void post_data_dump() NOT_JVMTI_RETURN;
 351   static void post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN;
 352   static void post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN;
 353   static void post_monitor_wait(JavaThread *thread, oop obj, jlong timeout) NOT_JVMTI_RETURN;
 354   static void post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) NOT_JVMTI_RETURN;
 355   static void post_object_free(JvmtiEnv* env, jlong tag) NOT_JVMTI_RETURN;
 356   static void post_resource_exhausted(jint resource_exhausted_flags, const char* detail) NOT_JVMTI_RETURN;
 357   static void record_vm_internal_object_allocation(oop object) NOT_JVMTI_RETURN;
 358   // Post objects collected by vm_object_alloc_event_collector.
 359   static void post_vm_object_alloc(JavaThread *thread, oop object) NOT_JVMTI_RETURN;
 360   // Collects vm internal objects for later event posting.
 361   inline static void vm_object_alloc_event_collector(oop object) {
 362     if (should_post_vm_object_alloc()) {
 363       record_vm_internal_object_allocation(object);
 364     }
 365   }
 366   inline static void post_array_size_exhausted() {
 367     if (should_post_resource_exhausted()) {
 368       post_resource_exhausted(JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR,
 369                               "Requested array size exceeds VM limit");
 370     }
 371   }
 372 
 373   static void cleanup_thread             (JavaThread* thread) NOT_JVMTI_RETURN;
 374   static void clear_detected_exception   (JavaThread* thread) NOT_JVMTI_RETURN;
 375 
 376   static void oops_do(OopClosure* f) NOT_JVMTI_RETURN;
 377   static void weak_oops_do(BoolObjectClosure* b, OopClosure* f) NOT_JVMTI_RETURN;
 378   static void gc_epilogue() NOT_JVMTI_RETURN;
 379 
 380   static void transition_pending_onload_raw_monitors() NOT_JVMTI_RETURN;
 381 
 382 #if INCLUDE_SERVICES
 383   // attach support
 384   static jint load_agent_library(const char *agent, const char *absParam, const char *options, outputStream* out) NOT_JVMTI_RETURN_(JNI_ERR);
 385 #endif
 386 
 387   // SetNativeMethodPrefix support
 388   static char** get_all_native_method_prefixes(int* count_ptr) NOT_JVMTI_RETURN_(NULL);
 389 
 390   // JavaThread lifecycle support:
 391   static jvmtiError cv_external_thread_to_JavaThread(ThreadsList * t_list,
 392                                                      jthread thread,
 393                                                      JavaThread ** jt_pp,
 394                                                      oop * thread_oop_p);
 395   static jvmtiError cv_oop_to_JavaThread(ThreadsList * t_list, oop thread_oop,
 396                                          JavaThread ** jt_pp);
 397 };
 398 
 399 // Support class used by JvmtiDynamicCodeEventCollector and others. It
 400 // describes a single code blob by name and address range.
 401 class JvmtiCodeBlobDesc : public CHeapObj<mtInternal> {
 402  private:
 403   char _name[64];
 404   address _code_begin;
 405   address _code_end;
 406 
 407  public:
 408   JvmtiCodeBlobDesc(const char *name, address code_begin, address code_end) {
 409     assert(name != NULL, "all code blobs must be named");
 410     strncpy(_name, name, sizeof(_name));
 411     _name[sizeof(_name)-1] = '\0';
 412     _code_begin = code_begin;
 413     _code_end = code_end;
 414   }
 415   char* name()                  { return _name; }
 416   address code_begin()          { return _code_begin; }
 417   address code_end()            { return _code_end; }
 418 };
 419 
 420 // JvmtiEventCollector is a helper class to setup thread for
 421 // event collection.
 422 class JvmtiEventCollector : public StackObj {
 423  private:
 424   JvmtiEventCollector* _prev;  // Save previous one to support nested event collector.
 425 
 426  public:
 427   void setup_jvmti_thread_state(); // Set this collector in current thread.
 428   void unset_jvmti_thread_state(); // Reset previous collector in current thread.
 429   virtual bool is_dynamic_code_event()   { return false; }
 430   virtual bool is_vm_object_alloc_event(){ return false; }
 431   JvmtiEventCollector *get_prev()        { return _prev; }
 432 };
 433 
 434 // A JvmtiDynamicCodeEventCollector is a helper class for the JvmtiExport
 435 // interface. It collects "dynamic code generated" events that are posted
 436 // while holding locks. When the event collector goes out of scope the
 437 // events will be posted.
 438 //
 439 // Usage :-
 440 //
 441 // {
 442 //   JvmtiDynamicCodeEventCollector event_collector;
 443 //   :
 444 //   { MutexLocker ml(...)
 445 //     :
 446 //     JvmtiExport::post_dynamic_code_generated_while_holding_locks(...)
 447 //   }
 448 //   // event collector goes out of scope => post events to profiler.
 449 // }
 450 
 451 class JvmtiDynamicCodeEventCollector : public JvmtiEventCollector {
 452  private:
 453   GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs;           // collected code blob events
 454 
 455   friend class JvmtiExport;
 456   void register_stub(const char* name, address start, address end);
 457 
 458  public:
 459   JvmtiDynamicCodeEventCollector()  NOT_JVMTI_RETURN;
 460   ~JvmtiDynamicCodeEventCollector() NOT_JVMTI_RETURN;
 461   bool is_dynamic_code_event()   { return true; }
 462 
 463 };
 464 
 465 // Used to record vm internally allocated object oops and post
 466 // vm object alloc event for objects visible to java world.
 467 // Constructor enables JvmtiThreadState flag and all vm allocated
 468 // objects are recorded in a growable array. When destructor is
 469 // called the vm object alloc event is posted for each objects
 470 // visible to java world.
 471 // See jvm.cpp file for its usage.
 472 //
 473 class JvmtiVMObjectAllocEventCollector : public JvmtiEventCollector {
 474  private:
 475   GrowableArray<oop>* _allocated; // field to record vm internally allocated object oop.
 476   bool _enable;                   // This flag is enabled in constructor and disabled
 477                                   // in destructor before posting event. To avoid
 478                                   // collection of objects allocated while running java code inside
 479                                   // agent post_vm_object_alloc() event handler.
 480 
 481   //GC support
 482   void oops_do(OopClosure* f);
 483 
 484   friend class JvmtiExport;
 485   // Record vm allocated object oop.
 486   inline void record_allocation(oop obj);
 487 
 488   //GC support
 489   static void oops_do_for_all_threads(OopClosure* f);
 490 
 491  public:
 492   JvmtiVMObjectAllocEventCollector()  NOT_JVMTI_RETURN;
 493   ~JvmtiVMObjectAllocEventCollector() NOT_JVMTI_RETURN;
 494   bool is_vm_object_alloc_event()   { return true; }
 495 
 496   bool is_enabled()                 { return _enable; }
 497   void set_enabled(bool on)         { _enable = on; }
 498 };
 499 
 500 
 501 
 502 // Marker class to disable the posting of VMObjectAlloc events
 503 // within its scope.
 504 //
 505 // Usage :-
 506 //
 507 // {
 508 //   NoJvmtiVMObjectAllocMark njm;
 509 //   :
 510 //   // VMObjAlloc event will not be posted
 511 //   JvmtiExport::vm_object_alloc_event_collector(obj);
 512 //   :
 513 // }
 514 
 515 class NoJvmtiVMObjectAllocMark : public StackObj {
 516  private:
 517   // enclosing collector if enabled, NULL otherwise
 518   JvmtiVMObjectAllocEventCollector *_collector;
 519 
 520   bool was_enabled()    { return _collector != NULL; }
 521 
 522  public:
 523   NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN;
 524   ~NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN;
 525 };
 526 
 527 
 528 // Base class for reporting GC events to JVMTI.
 529 class JvmtiGCMarker : public StackObj {
 530  public:
 531   JvmtiGCMarker() NOT_JVMTI_RETURN;
 532   ~JvmtiGCMarker() NOT_JVMTI_RETURN;
 533 };
 534 
 535 // JvmtiHideSingleStepping is a helper class for hiding
 536 // internal single step events.
 537 class JvmtiHideSingleStepping : public StackObj {
 538  private:
 539   bool         _single_step_hidden;
 540   JavaThread * _thread;
 541 
 542  public:
 543   JvmtiHideSingleStepping(JavaThread * thread) {
 544     assert(thread != NULL, "sanity check");
 545 
 546     _single_step_hidden = false;
 547     _thread = thread;
 548     if (JvmtiExport::should_post_single_step()) {
 549       _single_step_hidden = JvmtiExport::hide_single_stepping(_thread);
 550     }
 551   }
 552 
 553   ~JvmtiHideSingleStepping() {
 554     if (_single_step_hidden) {
 555       JvmtiExport::expose_single_stepping(_thread);
 556     }
 557   }
 558 };
 559 
 560 #endif // SHARE_VM_PRIMS_JVMTIEXPORT_HPP