src/share/vm/prims/jvmtiExport.hpp

Mon, 12 Nov 2012 16:15:05 -0500

author
hseigel
date
Mon, 12 Nov 2012 16:15:05 -0500
changeset 4278
070d523b96a7
parent 4165
fb19af007ffc
child 4267
bd7a7ce2e264
permissions
-rw-r--r--

8001471: Klass::cast() does nothing
Summary: Remove function Klass::cast() and calls to it.
Reviewed-by: dholmes, coleenp

     1 /*
     2  * Copyright (c) 1998, 2012, 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 #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   }
    63 // This class contains the JVMTI interface for the rest of hotspot.
    64 //
    65 class JvmtiExport : public AllStatic {
    66   friend class VMStructs;
    67  private:
    69 #if INCLUDE_JVMTI
    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;
    77 #endif // INCLUDE_JVMTI
    79   JVMTI_SUPPORT_FLAG(can_get_source_debug_extension)
    80   JVMTI_SUPPORT_FLAG(can_maintain_original_method_order)
    81   JVMTI_SUPPORT_FLAG(can_post_interpreter_events)
    82   JVMTI_SUPPORT_FLAG(can_post_on_exceptions)
    83   JVMTI_SUPPORT_FLAG(can_post_breakpoint)
    84   JVMTI_SUPPORT_FLAG(can_post_field_access)
    85   JVMTI_SUPPORT_FLAG(can_post_field_modification)
    86   JVMTI_SUPPORT_FLAG(can_post_method_entry)
    87   JVMTI_SUPPORT_FLAG(can_post_method_exit)
    88   JVMTI_SUPPORT_FLAG(can_pop_frame)
    89   JVMTI_SUPPORT_FLAG(can_force_early_return)
    91   friend class JvmtiEventControllerPrivate;  // should only modify these flags
    92   JVMTI_SUPPORT_FLAG(should_post_single_step)
    93   JVMTI_SUPPORT_FLAG(should_post_field_access)
    94   JVMTI_SUPPORT_FLAG(should_post_field_modification)
    95   JVMTI_SUPPORT_FLAG(should_post_class_load)
    96   JVMTI_SUPPORT_FLAG(should_post_class_prepare)
    97   JVMTI_SUPPORT_FLAG(should_post_class_unload)
    98   JVMTI_SUPPORT_FLAG(should_post_native_method_bind)
    99   JVMTI_SUPPORT_FLAG(should_post_compiled_method_load)
   100   JVMTI_SUPPORT_FLAG(should_post_compiled_method_unload)
   101   JVMTI_SUPPORT_FLAG(should_post_dynamic_code_generated)
   102   JVMTI_SUPPORT_FLAG(should_post_monitor_contended_enter)
   103   JVMTI_SUPPORT_FLAG(should_post_monitor_contended_entered)
   104   JVMTI_SUPPORT_FLAG(should_post_monitor_wait)
   105   JVMTI_SUPPORT_FLAG(should_post_monitor_waited)
   106   JVMTI_SUPPORT_FLAG(should_post_data_dump)
   107   JVMTI_SUPPORT_FLAG(should_post_garbage_collection_start)
   108   JVMTI_SUPPORT_FLAG(should_post_garbage_collection_finish)
   109   JVMTI_SUPPORT_FLAG(should_post_on_exceptions)
   111   // ------ the below maybe don't have to be (but are for now)
   112   // fixed conditions here ------------
   113   // any events can be enabled
   114   JVMTI_SUPPORT_FLAG(should_post_thread_life)
   115   JVMTI_SUPPORT_FLAG(should_post_object_free)
   116   JVMTI_SUPPORT_FLAG(should_post_resource_exhausted)
   118   // we are holding objects on the heap - need to talk to GC - e.g.
   119   // breakpoint info
   120   JVMTI_SUPPORT_FLAG(should_clean_up_heap_objects)
   121   JVMTI_SUPPORT_FLAG(should_post_vm_object_alloc)
   123   // If flag cannot be implemented, give an error if on=true
   124   static void report_unsupported(bool on);
   126   // these should only be called by the friend class
   127   friend class JvmtiManageCapabilities;
   128   inline static void set_can_modify_any_class(bool on) {
   129     JVMTI_ONLY(_can_modify_any_class = (on != 0);)
   130   }
   131   inline static void set_can_access_local_variables(bool on) {
   132     JVMTI_ONLY(_can_access_local_variables = (on != 0);)
   133   }
   134   inline static void set_can_hotswap_or_post_breakpoint(bool on) {
   135     JVMTI_ONLY(_can_hotswap_or_post_breakpoint = (on != 0);)
   136   }
   137   inline static void set_can_walk_any_space(bool on) {
   138     JVMTI_ONLY(_can_walk_any_space = (on != 0);)
   139   }
   141   enum {
   142     JVMTI_VERSION_MASK   = 0x70000000,
   143     JVMTI_VERSION_VALUE  = 0x30000000,
   144     JVMDI_VERSION_VALUE  = 0x20000000
   145   };
   147   static void post_field_modification(JavaThread *thread, Method* method, address location,
   148                                       KlassHandle field_klass, Handle object, jfieldID field,
   149                                       char sig_type, jvalue *value);
   152   // posts a DynamicCodeGenerated event (internal/private implementation).
   153   // The public post_dynamic_code_generated* functions make use of the
   154   // internal implementation.  Also called from JvmtiDeferredEvent::post()
   155   static void post_dynamic_code_generated_internal(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN;
   157  private:
   159   // GenerateEvents support to allow posting of CompiledMethodLoad and
   160   // DynamicCodeGenerated events for a given environment.
   161   friend class JvmtiCodeBlobEvents;
   163   static void post_compiled_method_load(JvmtiEnv* env, const jmethodID method, const jint length,
   164                                         const void *code_begin, const jint map_length,
   165                                         const jvmtiAddrLocationMap* map) NOT_JVMTI_RETURN;
   166   static void post_dynamic_code_generated(JvmtiEnv* env, const char *name, const void *code_begin,
   167                                           const void *code_end) NOT_JVMTI_RETURN;
   169   // The RedefineClasses() API breaks some invariants in the "regular"
   170   // system. For example, there are sanity checks when GC'ing nmethods
   171   // that require the containing class to be unloading. However, when a
   172   // method is redefined, the old method and nmethod can become GC'able
   173   // without the containing class unloading. The state of becoming
   174   // GC'able can be asynchronous to the RedefineClasses() call since
   175   // the old method may still be running and cannot be GC'ed until
   176   // after all old invocations have finished. Additionally, a method
   177   // that has not been redefined may have an nmethod that depends on
   178   // the redefined method. The dependent nmethod will get deopted in
   179   // this case and may also be GC'able without the containing class
   180   // being unloaded.
   181   //
   182   // This flag indicates whether RedefineClasses() has ever redefined
   183   // one or more classes during the lifetime of the VM. The flag should
   184   // only be set by the friend class and can be queried by other sub
   185   // systems as needed to relax invariant checks.
   186   static bool _has_redefined_a_class;
   187   friend class VM_RedefineClasses;
   188   inline static void set_has_redefined_a_class() {
   189     JVMTI_ONLY(_has_redefined_a_class = true;)
   190   }
   191   // Flag to indicate if the compiler has recorded all dependencies. When the
   192   // can_redefine_classes capability is enabled in the OnLoad phase then the compiler
   193   // records all dependencies from startup. However if the capability is first
   194   // enabled some time later then the dependencies recorded by the compiler
   195   // are incomplete. This flag is used by RedefineClasses to know if the
   196   // dependency information is complete or not.
   197   static bool _all_dependencies_are_recorded;
   199  public:
   200   inline static bool has_redefined_a_class() {
   201     JVMTI_ONLY(return _has_redefined_a_class);
   202     NOT_JVMTI(return false);
   203   }
   205   inline static bool all_dependencies_are_recorded() {
   206     return _all_dependencies_are_recorded;
   207   }
   209   inline static void set_all_dependencies_are_recorded(bool on) {
   210     _all_dependencies_are_recorded = (on != 0);
   211   }
   214   // let JVMTI know that the JVM_OnLoad code is running
   215   static void enter_onload_phase() NOT_JVMTI_RETURN;
   217   // let JVMTI know that the VM isn't up yet (and JVM_OnLoad code isn't running)
   218   static void enter_primordial_phase() NOT_JVMTI_RETURN;
   220   // let JVMTI know that the VM isn't up yet but JNI is live
   221   static void enter_start_phase() NOT_JVMTI_RETURN;
   223   // let JVMTI know that the VM is fully up and running now
   224   static void enter_live_phase() NOT_JVMTI_RETURN;
   226   // ------ can_* conditions (below) are set at OnLoad and never changed ------------
   227   inline static bool can_modify_any_class()                       {
   228     JVMTI_ONLY(return _can_modify_any_class);
   229     NOT_JVMTI(return false);
   230   }
   231   inline static bool can_access_local_variables()                 {
   232     JVMTI_ONLY(return _can_access_local_variables);
   233     NOT_JVMTI(return false);
   234   }
   235   inline static bool can_hotswap_or_post_breakpoint()             {
   236     JVMTI_ONLY(return _can_hotswap_or_post_breakpoint);
   237     NOT_JVMTI(return false);
   238   }
   239   inline static bool can_walk_any_space()                         {
   240     JVMTI_ONLY(return _can_walk_any_space);
   241     NOT_JVMTI(return false);
   242   }
   244   // field access management
   245   static address  get_field_access_count_addr() NOT_JVMTI_RETURN_(0);
   247   // field modification management
   248   static address  get_field_modification_count_addr() NOT_JVMTI_RETURN_(0);
   250   // -----------------
   252   static bool is_jvmti_version(jint version)                      {
   253     JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMTI_VERSION_VALUE);
   254     NOT_JVMTI(return false);
   255   }
   256   static bool is_jvmdi_version(jint version)                      {
   257     JVMTI_ONLY(return (version & JVMTI_VERSION_MASK) == JVMDI_VERSION_VALUE);
   258     NOT_JVMTI(return false);
   259   }
   260   static jint get_jvmti_interface(JavaVM *jvm, void **penv, jint version) NOT_JVMTI_RETURN_(0);
   261   static void decode_version_values(jint version, int * major, int * minor,
   262                                     int * micro) NOT_JVMTI_RETURN;
   264   // single stepping management methods
   265   static void at_single_stepping_point(JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN;
   266   static void expose_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN;
   267   static bool hide_single_stepping(JavaThread *thread) NOT_JVMTI_RETURN_(false);
   269   // Methods that notify the debugger that something interesting has happened in the VM.
   270   static void post_vm_start              () NOT_JVMTI_RETURN;
   271   static void post_vm_initialized        () NOT_JVMTI_RETURN;
   272   static void post_vm_death              () NOT_JVMTI_RETURN;
   274   static void post_single_step           (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN;
   275   static void post_raw_breakpoint        (JavaThread *thread, Method* method, address location) NOT_JVMTI_RETURN;
   277   static void post_exception_throw       (JavaThread *thread, Method* method, address location, oop exception) NOT_JVMTI_RETURN;
   278   static void notice_unwind_due_to_exception (JavaThread *thread, Method* method, address location, oop exception, bool in_handler_frame) NOT_JVMTI_RETURN;
   280   static oop jni_GetField_probe          (JavaThread *thread, jobject jobj,
   281     oop obj, Klass* klass, jfieldID fieldID, bool is_static)
   282     NOT_JVMTI_RETURN_(NULL);
   283   static oop jni_GetField_probe_nh       (JavaThread *thread, jobject jobj,
   284     oop obj, Klass* klass, jfieldID fieldID, bool is_static)
   285     NOT_JVMTI_RETURN_(NULL);
   286   static void post_field_access_by_jni   (JavaThread *thread, oop obj,
   287     Klass* klass, jfieldID fieldID, bool is_static) NOT_JVMTI_RETURN;
   288   static void post_field_access          (JavaThread *thread, Method* method,
   289     address location, KlassHandle field_klass, Handle object, jfieldID field) NOT_JVMTI_RETURN;
   290   static oop jni_SetField_probe          (JavaThread *thread, jobject jobj,
   291     oop obj, Klass* klass, jfieldID fieldID, bool is_static, char sig_type,
   292     jvalue *value) NOT_JVMTI_RETURN_(NULL);
   293   static oop jni_SetField_probe_nh       (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 void post_field_modification_by_jni(JavaThread *thread, oop obj,
   297     Klass* klass, jfieldID fieldID, bool is_static, char sig_type,
   298     jvalue *value);
   299   static void post_raw_field_modification(JavaThread *thread, Method* method,
   300     address location, KlassHandle field_klass, Handle object, jfieldID field,
   301     char sig_type, jvalue *value) NOT_JVMTI_RETURN;
   303   static void post_method_entry          (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN;
   304   static void post_method_exit           (JavaThread *thread, Method* method, frame current_frame) NOT_JVMTI_RETURN;
   306   static void post_class_load            (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN;
   307   static void post_class_unload          (Klass* klass) NOT_JVMTI_RETURN;
   308   static void post_class_prepare         (JavaThread *thread, Klass* klass) NOT_JVMTI_RETURN;
   310   static void post_thread_start          (JavaThread *thread) NOT_JVMTI_RETURN;
   311   static void post_thread_end            (JavaThread *thread) NOT_JVMTI_RETURN;
   313   // Support for java.lang.instrument agent loading.
   314   static bool _should_post_class_file_load_hook;
   315   inline static void set_should_post_class_file_load_hook(bool on)     { _should_post_class_file_load_hook = on;  }
   316   inline static bool should_post_class_file_load_hook()           {
   317     JVMTI_ONLY(return _should_post_class_file_load_hook);
   318     NOT_JVMTI(return false;)
   319   }
   320   static void post_class_file_load_hook(Symbol* h_name, Handle class_loader,
   321                                         Handle h_protection_domain,
   322                                         unsigned char **data_ptr, unsigned char **end_ptr,
   323                                         unsigned char **cached_data_ptr,
   324                                         jint *cached_length_ptr) NOT_JVMTI_RETURN;
   325   static void post_native_method_bind(Method* method, address* function_ptr) NOT_JVMTI_RETURN;
   326   static void post_compiled_method_load(nmethod *nm) NOT_JVMTI_RETURN;
   327   static void post_dynamic_code_generated(const char *name, const void *code_begin, const void *code_end) NOT_JVMTI_RETURN;
   329   // used to post a CompiledMethodUnload event
   330   static void post_compiled_method_unload(jmethodID mid, const void *code_begin) NOT_JVMTI_RETURN;
   332   // similiar to post_dynamic_code_generated except that it can be used to
   333   // post a DynamicCodeGenerated event while holding locks in the VM. Any event
   334   // posted using this function is recorded by the enclosing event collector
   335   // -- JvmtiDynamicCodeEventCollector.
   336   static void post_dynamic_code_generated_while_holding_locks(const char* name, address code_begin, address code_end) NOT_JVMTI_RETURN;
   338   static void post_garbage_collection_finish() NOT_JVMTI_RETURN;
   339   static void post_garbage_collection_start() NOT_JVMTI_RETURN;
   340   static void post_data_dump() NOT_JVMTI_RETURN;
   341   static void post_monitor_contended_enter(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN;
   342   static void post_monitor_contended_entered(JavaThread *thread, ObjectMonitor *obj_mntr) NOT_JVMTI_RETURN;
   343   static void post_monitor_wait(JavaThread *thread, oop obj, jlong timeout) NOT_JVMTI_RETURN;
   344   static void post_monitor_waited(JavaThread *thread, ObjectMonitor *obj_mntr, jboolean timed_out) NOT_JVMTI_RETURN;
   345   static void post_object_free(JvmtiEnv* env, jlong tag) NOT_JVMTI_RETURN;
   346   static void post_resource_exhausted(jint resource_exhausted_flags, const char* detail) NOT_JVMTI_RETURN;
   347   static void record_vm_internal_object_allocation(oop object) NOT_JVMTI_RETURN;
   348   // Post objects collected by vm_object_alloc_event_collector.
   349   static void post_vm_object_alloc(JavaThread *thread, oop object) NOT_JVMTI_RETURN;
   350   // Collects vm internal objects for later event posting.
   351   inline static void vm_object_alloc_event_collector(oop object) {
   352     if (should_post_vm_object_alloc()) {
   353       record_vm_internal_object_allocation(object);
   354     }
   355   }
   356   inline static void post_array_size_exhausted() {
   357     if (should_post_resource_exhausted()) {
   358       post_resource_exhausted(JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR,
   359                               "Requested array size exceeds VM limit");
   360     }
   361   }
   363   static void cleanup_thread             (JavaThread* thread) NOT_JVMTI_RETURN;
   365   static void oops_do(OopClosure* f) NOT_JVMTI_RETURN;
   366   static void weak_oops_do(BoolObjectClosure* b, OopClosure* f) NOT_JVMTI_RETURN;
   367   static void gc_epilogue() NOT_JVMTI_RETURN;
   369   static void transition_pending_onload_raw_monitors() NOT_JVMTI_RETURN;
   371   // attach support
   372   static jint load_agent_library(AttachOperation* op, outputStream* out) NOT_JVMTI_RETURN_(JNI_ERR);
   374   // SetNativeMethodPrefix support
   375   static char** get_all_native_method_prefixes(int* count_ptr) NOT_JVMTI_RETURN_(NULL);
   376 };
   378 // Support class used by JvmtiDynamicCodeEventCollector and others. It
   379 // describes a single code blob by name and address range.
   380 class JvmtiCodeBlobDesc : public CHeapObj<mtInternal> {
   381  private:
   382   char _name[64];
   383   address _code_begin;
   384   address _code_end;
   386  public:
   387   JvmtiCodeBlobDesc(const char *name, address code_begin, address code_end) {
   388     assert(name != NULL, "all code blobs must be named");
   389     strncpy(_name, name, sizeof(_name));
   390     _name[sizeof(_name)-1] = '\0';
   391     _code_begin = code_begin;
   392     _code_end = code_end;
   393   }
   394   char* name()                  { return _name; }
   395   address code_begin()          { return _code_begin; }
   396   address code_end()            { return _code_end; }
   397 };
   399 // JvmtiEventCollector is a helper class to setup thread for
   400 // event collection.
   401 class JvmtiEventCollector : public StackObj {
   402  private:
   403   JvmtiEventCollector* _prev;  // Save previous one to support nested event collector.
   405  public:
   406   void setup_jvmti_thread_state(); // Set this collector in current thread.
   407   void unset_jvmti_thread_state(); // Reset previous collector in current thread.
   408   virtual bool is_dynamic_code_event()   { return false; }
   409   virtual bool is_vm_object_alloc_event(){ return false; }
   410   JvmtiEventCollector *get_prev()        { return _prev; }
   411 };
   413 // A JvmtiDynamicCodeEventCollector is a helper class for the JvmtiExport
   414 // interface. It collects "dynamic code generated" events that are posted
   415 // while holding locks. When the event collector goes out of scope the
   416 // events will be posted.
   417 //
   418 // Usage :-
   419 //
   420 // {
   421 //   JvmtiDynamicCodeEventCollector event_collector;
   422 //   :
   423 //   { MutexLocker ml(...)
   424 //     :
   425 //     JvmtiExport::post_dynamic_code_generated_while_holding_locks(...)
   426 //   }
   427 //   // event collector goes out of scope => post events to profiler.
   428 // }
   430 class JvmtiDynamicCodeEventCollector : public JvmtiEventCollector {
   431  private:
   432   GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs;           // collected code blob events
   434   friend class JvmtiExport;
   435   void register_stub(const char* name, address start, address end);
   437  public:
   438   JvmtiDynamicCodeEventCollector()  NOT_JVMTI_RETURN;
   439   ~JvmtiDynamicCodeEventCollector() NOT_JVMTI_RETURN;
   440   bool is_dynamic_code_event()   { return true; }
   442 };
   444 // Used to record vm internally allocated object oops and post
   445 // vm object alloc event for objects visible to java world.
   446 // Constructor enables JvmtiThreadState flag and all vm allocated
   447 // objects are recorded in a growable array. When destructor is
   448 // called the vm object alloc event is posted for each objects
   449 // visible to java world.
   450 // See jvm.cpp file for its usage.
   451 //
   452 class JvmtiVMObjectAllocEventCollector : public JvmtiEventCollector {
   453  private:
   454   GrowableArray<oop>* _allocated; // field to record vm internally allocated object oop.
   455   bool _enable;                   // This flag is enabled in constructor and disabled
   456                                   // in destructor before posting event. To avoid
   457                                   // collection of objects allocated while running java code inside
   458                                   // agent post_vm_object_alloc() event handler.
   460   //GC support
   461   void oops_do(OopClosure* f);
   463   friend class JvmtiExport;
   464   // Record vm allocated object oop.
   465   inline void record_allocation(oop obj);
   467   //GC support
   468   static void oops_do_for_all_threads(OopClosure* f);
   470  public:
   471   JvmtiVMObjectAllocEventCollector()  NOT_JVMTI_RETURN;
   472   ~JvmtiVMObjectAllocEventCollector() NOT_JVMTI_RETURN;
   473   bool is_vm_object_alloc_event()   { return true; }
   475   bool is_enabled()                 { return _enable; }
   476   void set_enabled(bool on)         { _enable = on; }
   477 };
   481 // Marker class to disable the posting of VMObjectAlloc events
   482 // within its scope.
   483 //
   484 // Usage :-
   485 //
   486 // {
   487 //   NoJvmtiVMObjectAllocMark njm;
   488 //   :
   489 //   // VMObjAlloc event will not be posted
   490 //   JvmtiExport::vm_object_alloc_event_collector(obj);
   491 //   :
   492 // }
   494 class NoJvmtiVMObjectAllocMark : public StackObj {
   495  private:
   496   // enclosing collector if enabled, NULL otherwise
   497   JvmtiVMObjectAllocEventCollector *_collector;
   499   bool was_enabled()    { return _collector != NULL; }
   501  public:
   502   NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN;
   503   ~NoJvmtiVMObjectAllocMark() NOT_JVMTI_RETURN;
   504 };
   507 // Base class for reporting GC events to JVMTI.
   508 class JvmtiGCMarker : public StackObj {
   509  public:
   510   JvmtiGCMarker() NOT_JVMTI_RETURN;
   511   ~JvmtiGCMarker() NOT_JVMTI_RETURN;
   512 };
   514 // JvmtiHideSingleStepping is a helper class for hiding
   515 // internal single step events.
   516 class JvmtiHideSingleStepping : public StackObj {
   517  private:
   518   bool         _single_step_hidden;
   519   JavaThread * _thread;
   521  public:
   522   JvmtiHideSingleStepping(JavaThread * thread) {
   523     assert(thread != NULL, "sanity check");
   525     _single_step_hidden = false;
   526     _thread = thread;
   527     if (JvmtiExport::should_post_single_step()) {
   528       _single_step_hidden = JvmtiExport::hide_single_stepping(_thread);
   529     }
   530   }
   532   ~JvmtiHideSingleStepping() {
   533     if (_single_step_hidden) {
   534       JvmtiExport::expose_single_stepping(_thread);
   535     }
   536   }
   537 };
   539 #endif // SHARE_VM_PRIMS_JVMTIEXPORT_HPP

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