1 /*

     2  * Copyright (c) 1999, 2017, 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_JVMTIIMPL_HPP

    26 #define SHARE_VM_PRIMS_JVMTIIMPL_HPP

    27 

    28 #include "classfile/systemDictionary.hpp"

    29 #include "jvmtifiles/jvmti.h"

    30 #include "oops/objArrayOop.hpp"

    31 #include "prims/jvmtiEnvThreadState.hpp"

    32 #include "prims/jvmtiEventController.hpp"

    33 #include "prims/jvmtiTrace.hpp"

    34 #include "prims/jvmtiUtil.hpp"

    35 #include "runtime/stackValueCollection.hpp"

    36 #include "runtime/vm_operations.hpp"

    37 #include "utilities/ostream.hpp"

    38 

    39 //

    40 // Forward Declarations

    41 //

    42 

    43 class JvmtiBreakpoint;

    44 class JvmtiBreakpoints;

    45 

    46 

    47 ///////////////////////////////////////////////////////////////

    48 //

    49 // class GrowableCache, GrowableElement

    50 // Used by              : JvmtiBreakpointCache

    51 // Used by JVMTI methods: none directly.

    52 //

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

    54 //

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

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

    57 //     address GrowableElement::getCacheValue().

    58 //

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

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

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

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

    63 // to update its pointer to the address cache.

    64 //

    65 

    66 class GrowableElement : public CHeapObj<mtInternal> {

    67 public:

    68   virtual ~GrowableElement() {}

    69   virtual address getCacheValue()          =0;

    70   virtual bool equals(GrowableElement* e)  =0;

    71   virtual bool lessThan(GrowableElement *e)=0;

    72   virtual GrowableElement *clone()         =0;

    73   virtual void oops_do(OopClosure* f)      =0;

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

    75 };

    76 

    77 class GrowableCache VALUE_OBJ_CLASS_SPEC {

    78 

    79 private:

    80   // Object pointer passed into cache & listener functions.

    81   void *_this_obj;

    82 

    83   // Array of elements in the collection

    84   GrowableArray<GrowableElement *> *_elements;

    85 

    86   // Parallel array of cached values

    87   address *_cache;

    88 

    89   // Listener for changes to the _cache field.

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

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

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

    93 

    94   static bool equals(void *, GrowableElement *);

    95 

    96   // recache all elements after size change, notify listener

    97   void recache();

    98 

    99 public:

   100    GrowableCache();

   101    ~GrowableCache();

   102 

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

   104 

   105   // number of elements in the collection

   106   int length();

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

   108   GrowableElement* at(int index);

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

   110   int find(GrowableElement* e);

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

   112   void append(GrowableElement* e);

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

   114   void insert(GrowableElement* e);

   115   // remove the element at index, notify listener

   116   void remove (int index);

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

   118   void clear();

   119   // apply f to every element and update the cache

   120   void oops_do(OopClosure* f);

   121   // walk metadata to preserve for RedefineClasses

   122   void metadata_do(void f(Metadata*));

   123   // update the cache after a full gc

   124   void gc_epilogue();

   125 };

   126 

   127 

   128 ///////////////////////////////////////////////////////////////

   129 //

   130 // class JvmtiBreakpointCache

   131 // Used by              : JvmtiBreakpoints

   132 // Used by JVMTI methods: none directly.

   133 // Note   : typesafe wrapper for GrowableCache of JvmtiBreakpoint

   134 //

   135 

   136 class JvmtiBreakpointCache : public CHeapObj<mtInternal> {

   137 

   138 private:

   139   GrowableCache _cache;

   140 

   141 public:

   142   JvmtiBreakpointCache()  {}

   143   ~JvmtiBreakpointCache() {}

   144 

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

   146     _cache.initialize(this_obj,listener_fun);

   147   }

   148 

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

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

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

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

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

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

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

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

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

   158 };

   159 

   160 

   161 ///////////////////////////////////////////////////////////////

   162 //

   163 // class JvmtiBreakpoint

   164 // Used by              : JvmtiBreakpoints

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

   166 // Note: Extends GrowableElement for use in a GrowableCache

   167 //

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

   169 //

   170 

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

   172 

   173 class JvmtiBreakpoint : public GrowableElement {

   174 private:

   175   Method*               _method;

   176   int                   _bci;

   177   Bytecodes::Code       _orig_bytecode;

   178   oop                   _class_holder;  // keeps _method memory from being deallocated

   179 

   180 public:

   181   JvmtiBreakpoint();

   182   JvmtiBreakpoint(Method* m_method, jlocation location);

   183   bool equals(JvmtiBreakpoint& bp);

   184   bool lessThan(JvmtiBreakpoint &bp);

   185   void copy(JvmtiBreakpoint& bp);

   186   bool is_valid();

   187   address getBcp() const;

   188   void each_method_version_do(method_action meth_act);

   189   void set();

   190   void clear();

   191   void print_on(outputStream* out) const;

   192 

   193   Method* method() { return _method; }

   194 

   195   // GrowableElement implementation

   196   address getCacheValue()         { return getBcp(); }

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

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

   199   void oops_do(OopClosure* f)     {

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

   201     // unloaded and Method* memory reclaimed.

   202     f->do_oop(&_class_holder);

   203   }

   204   void metadata_do(void f(Metadata*)) {

   205     // walk metadata to preserve for RedefineClasses

   206     f(_method);

   207   }

   208 

   209   GrowableElement *clone()        {

   210     JvmtiBreakpoint *bp = new JvmtiBreakpoint();

   211     bp->copy(*this);

   212     return bp;

   213   }

   214 };

   215 

   216 

   217 ///////////////////////////////////////////////////////////////

   218 //

   219 // class JvmtiBreakpoints

   220 // Used by              : JvmtiCurrentBreakpoints

   221 // Used by JVMTI methods: none directly

   222 // Note: A Helper class

   223 //

   224 // JvmtiBreakpoints is a GrowableCache of JvmtiBreakpoint.

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

   226 //

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

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

   229 //

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

   231 // CHeap allocated to emphasize its similarity to JvmtiFramePops.

   232 //

   233 

   234 class JvmtiBreakpoints : public CHeapObj<mtInternal> {

   235 private:

   236 

   237   JvmtiBreakpointCache _bps;

   238 

   239   // These should only be used by VM_ChangeBreakpoints

   240   // to insure they only occur at safepoints.

   241   // Todo: add checks for safepoint

   242   friend class VM_ChangeBreakpoints;

   243   void set_at_safepoint(JvmtiBreakpoint& bp);

   244   void clear_at_safepoint(JvmtiBreakpoint& bp);

   245 

   246   static void do_element(GrowableElement *e);

   247 

   248 public:

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

   250   ~JvmtiBreakpoints();

   251 

   252   int length();

   253   void oops_do(OopClosure* f);

   254   void metadata_do(void f(Metadata*));

   255   void print();

   256 

   257   int  set(JvmtiBreakpoint& bp);

   258   int  clear(JvmtiBreakpoint& bp);

   259   void clearall_in_class_at_safepoint(Klass* klass);

   260   void gc_epilogue();

   261 };

   262 

   263 

   264 ///////////////////////////////////////////////////////////////

   265 //

   266 // class JvmtiCurrentBreakpoints

   267 //

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

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

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

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

   272 //    JvmtiFramePops).

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

   274 //

   275 

   276 class JvmtiCurrentBreakpoints : public AllStatic {

   277 

   278 private:

   279 

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

   281   static JvmtiBreakpoints *_jvmti_breakpoints;

   282 

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

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

   285   // It exists only to make is_breakpoint fast.

   286   static address          *_breakpoint_list;

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

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

   289 

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

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

   292 

   293 public:

   294   static void initialize();

   295   static void destroy();

   296 

   297   // lazily create _jvmti_breakpoints and _breakpoint_list

   298   static JvmtiBreakpoints& get_jvmti_breakpoints();

   299 

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

   301   static inline bool is_breakpoint(address bcp);

   302 

   303   static void oops_do(OopClosure* f);

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

   305   static void gc_epilogue();

   306 };

   307 

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

   309 bool JvmtiCurrentBreakpoints::is_breakpoint(address bcp) {

   310     address *bps = get_breakpoint_list();

   311     if (bps == NULL) return false;

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

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

   314     }

   315     return false;

   316 }

   317 

   318 

   319 ///////////////////////////////////////////////////////////////

   320 //

   321 // class VM_ChangeBreakpoints

   322 // Used by              : JvmtiBreakpoints

   323 // Used by JVMTI methods: none directly.

   324 // Note: A Helper class.

   325 //

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

   327 //

   328 

   329 class VM_ChangeBreakpoints : public VM_Operation {

   330 private:

   331   JvmtiBreakpoints* _breakpoints;

   332   int               _operation;

   333   JvmtiBreakpoint*  _bp;

   334 

   335 public:

   336   enum { SET_BREAKPOINT=0, CLEAR_BREAKPOINT=1 };

   337 

   338   VM_ChangeBreakpoints(int operation, JvmtiBreakpoint *bp) {

   339     JvmtiBreakpoints& current_bps = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();

   340     _breakpoints = &current_bps;

   341     _bp = bp;

   342     _operation = operation;

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

   344   }

   345 

   346   VMOp_Type type() const { return VMOp_ChangeBreakpoints; }

   347   void doit();

   348   void oops_do(OopClosure* f);

   349   void metadata_do(void f(Metadata*));

   350 };

   351 

   352 

   353 ///////////////////////////////////////////////////////////////

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

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

   356 // only safely be done by the VM thread

   357 //

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

   359 // we could get rid of the VM op

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

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

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

   363 // to prevent compiledVFrames from trying to add deferred updates

   364 // to the thread simultaneously.

   365 //

   366 class VM_GetOrSetLocal : public VM_Operation {

   367  protected:

   368   JavaThread* _thread;

   369   JavaThread* _calling_thread;

   370   jint        _depth;

   371   jint        _index;

   372   BasicType   _type;

   373   jvalue      _value;

   374   javaVFrame* _jvf;

   375   bool        _set;

   376 

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

   378   // frame.  Use VM_GetReceiver to do this.

   379   virtual bool getting_receiver() const { return false; }

   380 

   381   jvmtiError  _result;

   382 

   383   vframe* get_vframe();

   384   javaVFrame* get_java_vframe();

   385   bool check_slot_type(javaVFrame* vf);

   386 

   387 public:

   388   // Constructor for non-object getter

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

   390 

   391   // Constructor for object or non-object setter

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

   393 

   394   // Constructor for object getter

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

   396                    int index);

   397 

   398   VMOp_Type type() const { return VMOp_GetOrSetLocal; }

   399   jvalue value()         { return _value; }

   400   jvmtiError result()    { return _result; }

   401 

   402   bool doit_prologue();

   403   void doit();

   404   bool allow_nested_vm_operations() const;

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

   406 

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

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

   409 };

   410 

   411 class VM_GetReceiver : public VM_GetOrSetLocal {

   412  protected:

   413   virtual bool getting_receiver() const { return true; }

   414 

   415  public:

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

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

   418 };

   419 

   420 

   421 ///////////////////////////////////////////////////////////////

   422 //

   423 // class JvmtiSuspendControl

   424 //

   425 // Convenience routines for suspending and resuming threads.

   426 //

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

   428 // JvmtiSuspendControl interface.

   429 //

   430 // methods return true if successful

   431 //

   432 class JvmtiSuspendControl : public AllStatic {

   433 public:

   434   // suspend the thread, taking it to a safepoint

   435   static bool suspend(JavaThread *java_thread);

   436   // resume the thread

   437   static bool resume(JavaThread *java_thread);

   438 

   439   static void print();

   440 };

   441 

   442 

   443 /**

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

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

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

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

   448  * and then enqueued onto the JvmtiDeferredEventQueue, where the Service

   449  * thread will pick it up and post it.

   450  *

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

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

   453  */

   454 class JvmtiDeferredEvent VALUE_OBJ_CLASS_SPEC {

   455   friend class JvmtiDeferredEventQueue;

   456  private:

   457   typedef enum {

   458     TYPE_NONE,

   459     TYPE_COMPILED_METHOD_LOAD,

   460     TYPE_COMPILED_METHOD_UNLOAD,

   461     TYPE_DYNAMIC_CODE_GENERATED

   462   } Type;

   463 

   464   Type _type;

   465   union {

   466     nmethod* compiled_method_load;

   467     struct {

   468       nmethod* nm;

   469       jmethodID method_id;

   470       const void* code_begin;

   471     } compiled_method_unload;

   472     struct {

   473       const char* name;

   474       const void* code_begin;

   475       const void* code_end;

   476     } dynamic_code_generated;

   477   } _event_data;

   478 

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

   480 

   481  public:

   482 

   483   JvmtiDeferredEvent() : _type(TYPE_NONE) {}

   484 

   485   // Factory methods

   486   static JvmtiDeferredEvent compiled_method_load_event(nmethod* nm)

   487     NOT_JVMTI_RETURN_(JvmtiDeferredEvent());

   488   static JvmtiDeferredEvent compiled_method_unload_event(nmethod* nm,

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

   490   static JvmtiDeferredEvent dynamic_code_generated_event(

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

   492           NOT_JVMTI_RETURN_(JvmtiDeferredEvent());

   493 

   494   // Actually posts the event.

   495   void post() NOT_JVMTI_RETURN;

   496 };

   497 

   498 /**

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

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

   501  * when operating on the queue.

   502  */

   503 class JvmtiDeferredEventQueue : AllStatic {

   504   friend class JvmtiDeferredEvent;

   505  private:

   506   class QueueNode : public CHeapObj<mtInternal> {

   507    private:

   508     JvmtiDeferredEvent _event;

   509     QueueNode* _next;

   510 

   511    public:

   512     QueueNode(const JvmtiDeferredEvent& event)

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

   514 

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

   516     QueueNode* next() const { return _next; }

   517 

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

   519   };

   520 

   521   static QueueNode* _queue_head;             // Hold Service_lock to access

   522   static QueueNode* _queue_tail;             // Hold Service_lock to access

   523 

   524  public:

   525   // Must be holding Service_lock when calling these

   526   static bool has_events() NOT_JVMTI_RETURN_(false);

   527   static void enqueue(const JvmtiDeferredEvent& event) NOT_JVMTI_RETURN;

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

   529 };

   530 

   531 // Utility macro that checks for NULL pointers:

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

   533 

   534 #endif // SHARE_VM_PRIMS_JVMTIIMPL_HPP