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 /*

  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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  */

 #ifndef SHARE_VM_PRIMS_JVMTIIMPL_HPP

 #define SHARE_VM_PRIMS_JVMTIIMPL_HPP

 #include "classfile/systemDictionary.hpp"

 #include "jvmtifiles/jvmti.h"

 #include "oops/objArrayOop.hpp"

 #include "prims/jvmtiEnvThreadState.hpp"

 #include "prims/jvmtiEventController.hpp"

 #include "prims/jvmtiTrace.hpp"

 #include "prims/jvmtiUtil.hpp"

 #include "runtime/stackValueCollection.hpp"

 #include "runtime/vm_operations.hpp"

 //

 // Forward Declarations

 //

 class JvmtiBreakpoint;

 class JvmtiBreakpoints;

 ///////////////////////////////////////////////////////////////

 //

 // class GrowableCache, GrowableElement

 // Used by              : JvmtiBreakpointCache

 // Used by JVMTI methods: none directly.

 //

 // GrowableCache is a permanent CHeap growable array of <GrowableElement *>

 //

 // In addition, the GrowableCache maintains a NULL terminated cache array of type address

 // that's created from the element array using the function:

 //     address GrowableElement::getCacheValue().

 //

 // Whenever the GrowableArray changes size, the cache array gets recomputed into a new C_HEAP allocated

 // block of memory. Additionally, every time the cache changes its position in memory, the

 //    void (*_listener_fun)(void *this_obj, address* cache)

 // gets called with the cache's new address. This gives the user of the GrowableCache a callback

 // to update its pointer to the address cache.

 //

 class GrowableElement : public CHeapObj<mtInternal> {

 public:

   virtual address getCacheValue()          =0;

   virtual bool equals(GrowableElement* e)  =0;

   virtual bool lessThan(GrowableElement *e)=0;

   virtual GrowableElement *clone()         =0;

   virtual void oops_do(OopClosure* f)      =0;

   virtual void metadata_do(void f(Metadata*)) =0;

 };

 class GrowableCache VALUE_OBJ_CLASS_SPEC {

 private:

   // Object pointer passed into cache & listener functions.

   void *_this_obj;

   // Array of elements in the collection

   GrowableArray<GrowableElement *> *_elements;

   // Parallel array of cached values

   address *_cache;

   // Listener for changes to the _cache field.

   // Called whenever the _cache field has it's value changed

   // (but NOT when cached elements are recomputed).

   void (*_listener_fun)(void *, address*);

   static bool equals(void *, GrowableElement *);

   // recache all elements after size change, notify listener

   void recache();

 public:

    GrowableCache();

    ~GrowableCache();

   void initialize(void *this_obj, void listener_fun(void *, address*) );

   // number of elements in the collection

   int length();

   // get the value of the index element in the collection

   GrowableElement* at(int index);

   // find the index of the element, -1 if it doesn't exist

   int find(GrowableElement* e);

   // append a copy of the element to the end of the collection, notify listener

   void append(GrowableElement* e);

   // insert a copy of the element using lessthan(), notify listener

   void insert(GrowableElement* e);

   // remove the element at index, notify listener

   void remove (int index);

   // clear out all elements and release all heap space, notify listener

   void clear();

   // apply f to every element and update the cache

   void oops_do(OopClosure* f);

   // walk metadata to preserve for RedefineClasses

   void metadata_do(void f(Metadata*));

   // update the cache after a full gc

   void gc_epilogue();

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiBreakpointCache

 // Used by              : JvmtiBreakpoints

 // Used by JVMTI methods: none directly.

 // Note   : typesafe wrapper for GrowableCache of JvmtiBreakpoint

 //

 class JvmtiBreakpointCache : public CHeapObj<mtInternal> {

 private:

   GrowableCache _cache;

 public:

   JvmtiBreakpointCache()  {}

   ~JvmtiBreakpointCache() {}

   void initialize(void *this_obj, void listener_fun(void *, address*) ) {

     _cache.initialize(this_obj,listener_fun);

   }

   int length()                          { return _cache.length(); }

   JvmtiBreakpoint& at(int index)        { return (JvmtiBreakpoint&) *(_cache.at(index)); }

   int find(JvmtiBreakpoint& e)          { return _cache.find((GrowableElement *) &e); }

   void append(JvmtiBreakpoint& e)       { _cache.append((GrowableElement *) &e); }

   void remove (int index)               { _cache.remove(index); }

   void clear()                          { _cache.clear(); }

   void oops_do(OopClosure* f)           { _cache.oops_do(f); }

   void metadata_do(void f(Metadata*))   { _cache.metadata_do(f); }

   void gc_epilogue()                    { _cache.gc_epilogue(); }

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiBreakpoint

 // Used by              : JvmtiBreakpoints

 // Used by JVMTI methods: SetBreakpoint, ClearBreakpoint, ClearAllBreakpoints

 // Note: Extends GrowableElement for use in a GrowableCache

 //

 // A JvmtiBreakpoint describes a location (class, method, bci) to break at.

 //

 typedef void (Method::*method_action)(int _bci);

 class JvmtiBreakpoint : public GrowableElement {

 private:

   Method*               _method;

   int                   _bci;

   Bytecodes::Code       _orig_bytecode;

   oop                   _class_holder;  // keeps _method memory from being deallocated

 public:

   JvmtiBreakpoint();

   JvmtiBreakpoint(Method* m_method, jlocation location);

   bool equals(JvmtiBreakpoint& bp);

   bool lessThan(JvmtiBreakpoint &bp);

   void copy(JvmtiBreakpoint& bp);

   bool is_valid();

   address getBcp();

   void each_method_version_do(method_action meth_act);

   void set();

   void clear();

   void print();

   Method* method() { return _method; }

   // GrowableElement implementation

   address getCacheValue()         { return getBcp(); }

   bool lessThan(GrowableElement* e) { Unimplemented(); return false; }

   bool equals(GrowableElement* e) { return equals((JvmtiBreakpoint&) *e); }

   void oops_do(OopClosure* f)     {

     // Mark the method loader as live so the Method* class loader doesn't get

     // unloaded and Method* memory reclaimed.

     f->do_oop(&_class_holder);

   }

   void metadata_do(void f(Metadata*)) {

     // walk metadata to preserve for RedefineClasses

     f(_method);

   }

   GrowableElement *clone()        {

     JvmtiBreakpoint *bp = new JvmtiBreakpoint();

     bp->copy(*this);

     return bp;

   }

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiBreakpoints

 // Used by              : JvmtiCurrentBreakpoints

 // Used by JVMTI methods: none directly

 // Note: A Helper class

 //

 // JvmtiBreakpoints is a GrowableCache of JvmtiBreakpoint.

 // All changes to the GrowableCache occur at a safepoint using VM_ChangeBreakpoints.

 //

 // Because _bps is only modified at safepoints, its possible to always use the

 // cached byte code pointers from _bps without doing any synchronization (see JvmtiCurrentBreakpoints).

 //

 // It would be possible to make JvmtiBreakpoints a static class, but I've made it

 // CHeap allocated to emphasize its similarity to JvmtiFramePops.

 //

 class JvmtiBreakpoints : public CHeapObj<mtInternal> {

 private:

   JvmtiBreakpointCache _bps;

   // These should only be used by VM_ChangeBreakpoints

   // to insure they only occur at safepoints.

   // Todo: add checks for safepoint

   friend class VM_ChangeBreakpoints;

   void set_at_safepoint(JvmtiBreakpoint& bp);

   void clear_at_safepoint(JvmtiBreakpoint& bp);

   static void do_element(GrowableElement *e);

 public:

   JvmtiBreakpoints(void listener_fun(void *, address *));

   ~JvmtiBreakpoints();

   int length();

   void oops_do(OopClosure* f);

   void metadata_do(void f(Metadata*));

   void print();

   int  set(JvmtiBreakpoint& bp);

   int  clear(JvmtiBreakpoint& bp);

   void clearall_in_class_at_safepoint(Klass* klass);

   void gc_epilogue();

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiCurrentBreakpoints

 //

 // A static wrapper class for the JvmtiBreakpoints that provides:

 // 1. a fast inlined function to check if a byte code pointer is a breakpoint (is_breakpoint).

 // 2. a function for lazily creating the JvmtiBreakpoints class (this is not strictly necessary,

 //    but I'm copying the code from JvmtiThreadState which needs to lazily initialize

 //    JvmtiFramePops).

 // 3. An oops_do entry point for GC'ing the breakpoint array.

 //

 class JvmtiCurrentBreakpoints : public AllStatic {

 private:

   // Current breakpoints, lazily initialized by get_jvmti_breakpoints();

   static JvmtiBreakpoints *_jvmti_breakpoints;

   // NULL terminated cache of byte-code pointers corresponding to current breakpoints.

   // Updated only at safepoints (with listener_fun) when the cache is moved.

   // It exists only to make is_breakpoint fast.

   static address          *_breakpoint_list;

   static inline void set_breakpoint_list(address *breakpoint_list) { _breakpoint_list = breakpoint_list; }

   static inline address *get_breakpoint_list()                     { return _breakpoint_list; }

   // Listener for the GrowableCache in _jvmti_breakpoints, updates _breakpoint_list.

   static void listener_fun(void *this_obj, address *cache);

 public:

   static void initialize();

   static void destroy();

   // lazily create _jvmti_breakpoints and _breakpoint_list

   static JvmtiBreakpoints& get_jvmti_breakpoints();

   // quickly test whether the bcp matches a cached breakpoint in the list

   static inline bool is_breakpoint(address bcp);

   static void oops_do(OopClosure* f);

   static void metadata_do(void f(Metadata*)) NOT_JVMTI_RETURN;

   static void gc_epilogue();

 };

 // quickly test whether the bcp matches a cached breakpoint in the list

 bool JvmtiCurrentBreakpoints::is_breakpoint(address bcp) {

     address *bps = get_breakpoint_list();

     if (bps == NULL) return false;

     for ( ; (*bps) != NULL; bps++) {

       if ((*bps) == bcp) return true;

     }

     return false;

 }

 ///////////////////////////////////////////////////////////////

 //

 // class VM_ChangeBreakpoints

 // Used by              : JvmtiBreakpoints

 // Used by JVMTI methods: none directly.

 // Note: A Helper class.

 //

 // VM_ChangeBreakpoints implements a VM_Operation for ALL modifications to the JvmtiBreakpoints class.

 //

 class VM_ChangeBreakpoints : public VM_Operation {

 private:

   JvmtiBreakpoints* _breakpoints;

   int               _operation;

   JvmtiBreakpoint*  _bp;

 public:

   enum { SET_BREAKPOINT=0, CLEAR_BREAKPOINT=1 };

   VM_ChangeBreakpoints(int operation, JvmtiBreakpoint *bp) {

     JvmtiBreakpoints& current_bps = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();

     _breakpoints = &current_bps;

     _bp = bp;

     _operation = operation;

     assert(bp != NULL, "bp != NULL");

   }

   VMOp_Type type() const { return VMOp_ChangeBreakpoints; }

   void doit();

   void oops_do(OopClosure* f);

   void metadata_do(void f(Metadata*));

 };

 ///////////////////////////////////////////////////////////////

 // The get/set local operations must only be done by the VM thread

 // because the interpreter version needs to access oop maps, which can

 // only safely be done by the VM thread

 //

 // I'm told that in 1.5 oop maps are now protected by a lock and

 // we could get rid of the VM op

 // However if the VM op is removed then the target thread must

 // be suspended AND a lock will be needed to prevent concurrent

 // setting of locals to the same java thread. This lock is needed

 // to prevent compiledVFrames from trying to add deferred updates

 // to the thread simultaneously.

 //

 class VM_GetOrSetLocal : public VM_Operation {

  protected:

   JavaThread* _thread;

   JavaThread* _calling_thread;

   jint        _depth;

   jint        _index;

   BasicType   _type;

   jvalue      _value;

   javaVFrame* _jvf;

   bool        _set;

   // It is possible to get the receiver out of a non-static native wrapper

   // frame.  Use VM_GetReceiver to do this.

   virtual bool getting_receiver() const { return false; }

   jvmtiError  _result;

   vframe* get_vframe();

   javaVFrame* get_java_vframe();

   bool check_slot_type(javaVFrame* vf);

 public:

   // Constructor for non-object getter

   VM_GetOrSetLocal(JavaThread* thread, jint depth, jint index, BasicType type);

   // Constructor for object or non-object setter

   VM_GetOrSetLocal(JavaThread* thread, jint depth, jint index, BasicType type, jvalue value);

   // Constructor for object getter

   VM_GetOrSetLocal(JavaThread* thread, JavaThread* calling_thread, jint depth,

                    int index);

   VMOp_Type type() const { return VMOp_GetOrSetLocal; }

   jvalue value()         { return _value; }

   jvmtiError result()    { return _result; }

   bool doit_prologue();

   void doit();

   bool allow_nested_vm_operations() const;

   const char* name() const                       { return "get/set locals"; }

   // Check that the klass is assignable to a type with the given signature.

   static bool is_assignable(const char* ty_sign, Klass* klass, Thread* thread);

 };

 class VM_GetReceiver : public VM_GetOrSetLocal {

  protected:

   virtual bool getting_receiver() const { return true; }

  public:

   VM_GetReceiver(JavaThread* thread, JavaThread* calling_thread, jint depth);

   const char* name() const                       { return "get receiver"; }

 };

 ///////////////////////////////////////////////////////////////

 //

 // class JvmtiSuspendControl

 //

 // Convenience routines for suspending and resuming threads.

 //

 // All attempts by JVMTI to suspend and resume threads must go through the

 // JvmtiSuspendControl interface.

 //

 // methods return true if successful

 //

 class JvmtiSuspendControl : public AllStatic {

 public:

   // suspend the thread, taking it to a safepoint

   static bool suspend(JavaThread *java_thread);

   // resume the thread

   static bool resume(JavaThread *java_thread);

   static void print();

 };

 /**

  * When a thread (such as the compiler thread or VM thread) cannot post a

  * JVMTI event itself because the event needs to be posted from a Java

  * thread, then it can defer the event to the Service thread for posting.

  * The information needed to post the event is encapsulated into this class

  * and then enqueued onto the JvmtiDeferredEventQueue, where the Service

  * thread will pick it up and post it.

  *

  * This is currently only used for posting compiled-method-load and unload

  * events, which we don't want posted from the compiler thread.

  */

 class JvmtiDeferredEvent VALUE_OBJ_CLASS_SPEC {

   friend class JvmtiDeferredEventQueue;

  private:

   typedef enum {

     TYPE_NONE,

     TYPE_COMPILED_METHOD_LOAD,

     TYPE_COMPILED_METHOD_UNLOAD,

     TYPE_DYNAMIC_CODE_GENERATED

   } Type;

   Type _type;

   union {

     nmethod* compiled_method_load;

     struct {

       nmethod* nm;

       jmethodID method_id;

       const void* code_begin;

     } compiled_method_unload;

     struct {

       const char* name;

       const void* code_begin;

       const void* code_end;

     } dynamic_code_generated;

   } _event_data;

   JvmtiDeferredEvent(Type t) : _type(t) {}

  public:

   JvmtiDeferredEvent() : _type(TYPE_NONE) {}

   // Factory methods

   static JvmtiDeferredEvent compiled_method_load_event(nmethod* nm)

     NOT_JVMTI_RETURN_(JvmtiDeferredEvent());

   static JvmtiDeferredEvent compiled_method_unload_event(nmethod* nm,

       jmethodID id, const void* code) NOT_JVMTI_RETURN_(JvmtiDeferredEvent());

   static JvmtiDeferredEvent dynamic_code_generated_event(

       const char* name, const void* begin, const void* end)

           NOT_JVMTI_RETURN_(JvmtiDeferredEvent());

   // Actually posts the event.

   void post() NOT_JVMTI_RETURN;

 };

 /**

  * Events enqueued on this queue wake up the Service thread which dequeues

  * and posts the events.  The Service_lock is required to be held

  * when operating on the queue (except for the "pending" events).

  */

 class JvmtiDeferredEventQueue : AllStatic {

   friend class JvmtiDeferredEvent;

  private:

   class QueueNode : public CHeapObj<mtInternal> {

    private:

     JvmtiDeferredEvent _event;

     QueueNode* _next;

    public:

     QueueNode(const JvmtiDeferredEvent& event)

       : _event(event), _next(NULL) {}

     const JvmtiDeferredEvent& event() const { return _event; }

     QueueNode* next() const { return _next; }

     void set_next(QueueNode* next) { _next = next; }

   };

   static QueueNode* _queue_head;             // Hold Service_lock to access

   static QueueNode* _queue_tail;             // Hold Service_lock to access

   static volatile QueueNode* _pending_list;  // Uses CAS for read/update

   // Transfers events from the _pending_list to the _queue.

   static void process_pending_events() NOT_JVMTI_RETURN;

  public:

   // Must be holding Service_lock when calling these

   static bool has_events() NOT_JVMTI_RETURN_(false);

   static void enqueue(const JvmtiDeferredEvent& event) NOT_JVMTI_RETURN;

   static JvmtiDeferredEvent dequeue() NOT_JVMTI_RETURN_(JvmtiDeferredEvent());

   // Used to enqueue events without using a lock, for times (such as during

   // safepoint) when we can't or don't want to lock the Service_lock.

   //

   // Events will be held off to the side until there's a call to

   // dequeue(), enqueue(), or process_pending_events() (all of which require

   // the holding of the Service_lock), and will be enqueued at that time.

   static void add_pending_event(const JvmtiDeferredEvent&) NOT_JVMTI_RETURN;

 };

 // Utility macro that checks for NULL pointers:

 #define NULL_CHECK(X, Y) if ((X) == NULL) { return (Y); }

 #endif // SHARE_VM_PRIMS_JVMTIIMPL_HPP