1 /*
   2  * Copyright (c) 1999, 2013, 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 
  38 //
  39 // Forward Declarations
  40 //
  41 
  42 class JvmtiBreakpoint;
  43 class JvmtiBreakpoints;
  44 
  45 
  46 ///////////////////////////////////////////////////////////////
  47 //
  48 // class GrowableCache, GrowableElement
  49 // Used by              : JvmtiBreakpointCache
  50 // Used by JVMTI methods: none directly.
  51 //
  52 // GrowableCache is a permanent CHeap growable array of <GrowableElement *>
  53 //
  54 // In addition, the GrowableCache maintains a NULL terminated cache array of type address
  55 // that's created from the element array using the function:
  56 //     address GrowableElement::getCacheValue().
  57 //
  58 // Whenever the GrowableArray changes size, the cache array gets recomputed into a new C_HEAP allocated
  59 // block of memory. Additionally, every time the cache changes its position in memory, the
  60 //    void (*_listener_fun)(void *this_obj, address* cache)
  61 // gets called with the cache's new address. This gives the user of the GrowableCache a callback
  62 // to update its pointer to the address cache.
  63 //
  64 
  65 class GrowableElement : public CHeapObj<mtInternal> {
  66 public:
  67   virtual address getCacheValue()          =0;
  68   virtual bool equals(GrowableElement* e)  =0;
  69   virtual bool lessThan(GrowableElement *e)=0;
  70   virtual GrowableElement *clone()         =0;
  71   virtual void oops_do(OopClosure* f)      =0;
  72 };
  73 
  74 class GrowableCache VALUE_OBJ_CLASS_SPEC {
  75 
  76 private:
  77   // Object pointer passed into cache & listener functions.
  78   void *_this_obj;
  79 
  80   // Array of elements in the collection
  81   GrowableArray<GrowableElement *> *_elements;
  82 
  83   // Parallel array of cached values
  84   address *_cache;
  85 
  86   // Listener for changes to the _cache field.
  87   // Called whenever the _cache field has it's value changed
  88   // (but NOT when cached elements are recomputed).
  89   void (*_listener_fun)(void *, address*);
  90 
  91   static bool equals(void *, GrowableElement *);
  92 
  93   // recache all elements after size change, notify listener
  94   void recache();
  95 
  96 public:
  97    GrowableCache();
  98    ~GrowableCache();
  99 
 100   void initialize(void *this_obj, void listener_fun(void *, address*) );
 101 
 102   // number of elements in the collection
 103   int length();
 104   // get the value of the index element in the collection
 105   GrowableElement* at(int index);
 106   // find the index of the element, -1 if it doesn't exist
 107   int find(GrowableElement* e);
 108   // append a copy of the element to the end of the collection, notify listener
 109   void append(GrowableElement* e);
 110   // insert a copy of the element using lessthan(), notify listener
 111   void insert(GrowableElement* e);
 112   // remove the element at index, notify listener
 113   void remove (int index);
 114   // clear out all elements and release all heap space, notify listener
 115   void clear();
 116   // apply f to every element and update the cache
 117   void oops_do(OopClosure* f);
 118   // update the cache after a full gc
 119   void gc_epilogue();
 120 };
 121 
 122 
 123 ///////////////////////////////////////////////////////////////
 124 //
 125 // class JvmtiBreakpointCache
 126 // Used by              : JvmtiBreakpoints
 127 // Used by JVMTI methods: none directly.
 128 // Note   : typesafe wrapper for GrowableCache of JvmtiBreakpoint
 129 //
 130 
 131 class JvmtiBreakpointCache : public CHeapObj<mtInternal> {
 132 
 133 private:
 134   GrowableCache _cache;
 135 
 136 public:
 137   JvmtiBreakpointCache()  {}
 138   ~JvmtiBreakpointCache() {}
 139 
 140   void initialize(void *this_obj, void listener_fun(void *, address*) ) {
 141     _cache.initialize(this_obj,listener_fun);
 142   }
 143 
 144   int length()                          { return _cache.length(); }
 145   JvmtiBreakpoint& at(int index)        { return (JvmtiBreakpoint&) *(_cache.at(index)); }
 146   int find(JvmtiBreakpoint& e)          { return _cache.find((GrowableElement *) &e); }
 147   void append(JvmtiBreakpoint& e)       { _cache.append((GrowableElement *) &e); }
 148   void remove (int index)               { _cache.remove(index); }
 149   void clear()                          { _cache.clear(); }
 150   void oops_do(OopClosure* f)           { _cache.oops_do(f); }
 151   void gc_epilogue()                    { _cache.gc_epilogue(); }
 152 };
 153 
 154 
 155 ///////////////////////////////////////////////////////////////
 156 //
 157 // class JvmtiBreakpoint
 158 // Used by              : JvmtiBreakpoints
 159 // Used by JVMTI methods: SetBreakpoint, ClearBreakpoint, ClearAllBreakpoints
 160 // Note: Extends GrowableElement for use in a GrowableCache
 161 //
 162 // A JvmtiBreakpoint describes a location (class, method, bci) to break at.
 163 //
 164 
 165 typedef void (Method::*method_action)(int _bci);
 166 
 167 class JvmtiBreakpoint : public GrowableElement {
 168 private:
 169   Method*               _method;
 170   int                   _bci;
 171   Bytecodes::Code       _orig_bytecode;
 172   oop                   _class_loader;
 173 
 174 public:
 175   JvmtiBreakpoint();
 176   JvmtiBreakpoint(Method* m_method, jlocation location);
 177   bool equals(JvmtiBreakpoint& bp);
 178   bool lessThan(JvmtiBreakpoint &bp);
 179   void copy(JvmtiBreakpoint& bp);
 180   bool is_valid();
 181   address getBcp();
 182   void each_method_version_do(method_action meth_act);
 183   void set();
 184   void clear();
 185   void print();
 186 
 187   Method* method() { return _method; }
 188 
 189   // GrowableElement implementation
 190   address getCacheValue()         { return getBcp(); }
 191   bool lessThan(GrowableElement* e) { Unimplemented(); return false; }
 192   bool equals(GrowableElement* e) { return equals((JvmtiBreakpoint&) *e); }
 193   void oops_do(OopClosure* f)     {
 194     // Mark the method loader as live
 195     f->do_oop(&_class_loader);
 196   }
 197   GrowableElement *clone()        {
 198     JvmtiBreakpoint *bp = new JvmtiBreakpoint();
 199     bp->copy(*this);
 200     return bp;
 201   }
 202 };
 203 
 204 
 205 ///////////////////////////////////////////////////////////////
 206 //
 207 // class VM_ChangeBreakpoints
 208 // Used by              : JvmtiBreakpoints
 209 // Used by JVMTI methods: none directly.
 210 // Note: A Helper class.
 211 //
 212 // VM_ChangeBreakpoints implements a VM_Operation for ALL modifications to the JvmtiBreakpoints class.
 213 //
 214 
 215 class VM_ChangeBreakpoints : public VM_Operation {
 216 private:
 217   JvmtiBreakpoints* _breakpoints;
 218   int               _operation;
 219   JvmtiBreakpoint*  _bp;
 220 
 221 public:
 222   enum { SET_BREAKPOINT=0, CLEAR_BREAKPOINT=1, CLEAR_ALL_BREAKPOINT=2 };
 223 
 224   VM_ChangeBreakpoints(JvmtiBreakpoints* breakpoints, int operation) {
 225     _breakpoints = breakpoints;
 226     _bp = NULL;
 227     _operation = operation;
 228     assert(breakpoints != NULL, "breakpoints != NULL");
 229     assert(operation == CLEAR_ALL_BREAKPOINT, "unknown breakpoint operation");
 230   }
 231   VM_ChangeBreakpoints(JvmtiBreakpoints* breakpoints, int operation, JvmtiBreakpoint *bp) {
 232     _breakpoints = breakpoints;
 233     _bp = bp;
 234     _operation = operation;
 235     assert(breakpoints != NULL, "breakpoints != NULL");
 236     assert(bp != NULL, "bp != NULL");
 237     assert(operation == SET_BREAKPOINT || operation == CLEAR_BREAKPOINT , "unknown breakpoint operation");
 238   }
 239 
 240   VMOp_Type type() const { return VMOp_ChangeBreakpoints; }
 241   void doit();
 242   void oops_do(OopClosure* f);
 243 };
 244 
 245 
 246 ///////////////////////////////////////////////////////////////
 247 //
 248 // class JvmtiBreakpoints
 249 // Used by              : JvmtiCurrentBreakpoints
 250 // Used by JVMTI methods: none directly
 251 // Note: A Helper class
 252 //
 253 // JvmtiBreakpoints is a GrowableCache of JvmtiBreakpoint.
 254 // All changes to the GrowableCache occur at a safepoint using VM_ChangeBreakpoints.
 255 //
 256 // Because _bps is only modified at safepoints, its possible to always use the
 257 // cached byte code pointers from _bps without doing any synchronization (see JvmtiCurrentBreakpoints).
 258 //
 259 // It would be possible to make JvmtiBreakpoints a static class, but I've made it
 260 // CHeap allocated to emphasize its similarity to JvmtiFramePops.
 261 //
 262 
 263 class JvmtiBreakpoints : public CHeapObj<mtInternal> {
 264 private:
 265 
 266   JvmtiBreakpointCache _bps;
 267 
 268   // These should only be used by VM_ChangeBreakpoints
 269   // to insure they only occur at safepoints.
 270   // Todo: add checks for safepoint
 271   friend class VM_ChangeBreakpoints;
 272   void set_at_safepoint(JvmtiBreakpoint& bp);
 273   void clear_at_safepoint(JvmtiBreakpoint& bp);
 274   void clearall_at_safepoint();
 275 
 276   static void do_element(GrowableElement *e);
 277 
 278 public:
 279   JvmtiBreakpoints(void listener_fun(void *, address *));
 280   ~JvmtiBreakpoints();
 281 
 282   int length();
 283   void oops_do(OopClosure* f);
 284   void print();
 285 
 286   int  set(JvmtiBreakpoint& bp);
 287   int  clear(JvmtiBreakpoint& bp);
 288   void clearall_in_class_at_safepoint(Klass* klass);
 289   void clearall();
 290   void gc_epilogue();
 291 };
 292 
 293 
 294 ///////////////////////////////////////////////////////////////
 295 //
 296 // class JvmtiCurrentBreakpoints
 297 //
 298 // A static wrapper class for the JvmtiBreakpoints that provides:
 299 // 1. a fast inlined function to check if a byte code pointer is a breakpoint (is_breakpoint).
 300 // 2. a function for lazily creating the JvmtiBreakpoints class (this is not strictly necessary,
 301 //    but I'm copying the code from JvmtiThreadState which needs to lazily initialize
 302 //    JvmtiFramePops).
 303 // 3. An oops_do entry point for GC'ing the breakpoint array.
 304 //
 305 
 306 class JvmtiCurrentBreakpoints : public AllStatic {
 307 
 308 private:
 309 
 310   // Current breakpoints, lazily initialized by get_jvmti_breakpoints();
 311   static JvmtiBreakpoints *_jvmti_breakpoints;
 312 
 313   // NULL terminated cache of byte-code pointers corresponding to current breakpoints.
 314   // Updated only at safepoints (with listener_fun) when the cache is moved.
 315   // It exists only to make is_breakpoint fast.
 316   static address          *_breakpoint_list;
 317   static inline void set_breakpoint_list(address *breakpoint_list) { _breakpoint_list = breakpoint_list; }
 318   static inline address *get_breakpoint_list()                     { return _breakpoint_list; }
 319 
 320   // Listener for the GrowableCache in _jvmti_breakpoints, updates _breakpoint_list.
 321   static void listener_fun(void *this_obj, address *cache);
 322 
 323 public:
 324   static void initialize();
 325   static void destroy();
 326 
 327   // lazily create _jvmti_breakpoints and _breakpoint_list
 328   static JvmtiBreakpoints& get_jvmti_breakpoints();
 329 
 330   // quickly test whether the bcp matches a cached breakpoint in the list
 331   static inline bool is_breakpoint(address bcp);
 332 
 333   static void oops_do(OopClosure* f);
 334   static void gc_epilogue();
 335 };
 336 
 337 // quickly test whether the bcp matches a cached breakpoint in the list
 338 bool JvmtiCurrentBreakpoints::is_breakpoint(address bcp) {
 339     address *bps = get_breakpoint_list();
 340     if (bps == NULL) return false;
 341     for ( ; (*bps) != NULL; bps++) {
 342       if ((*bps) == bcp) return true;
 343     }
 344     return false;
 345 }
 346 
 347 ///////////////////////////////////////////////////////////////
 348 // The get/set local operations must only be done by the VM thread
 349 // because the interpreter version needs to access oop maps, which can
 350 // only safely be done by the VM thread
 351 //
 352 // I'm told that in 1.5 oop maps are now protected by a lock and
 353 // we could get rid of the VM op
 354 // However if the VM op is removed then the target thread must
 355 // be suspended AND a lock will be needed to prevent concurrent
 356 // setting of locals to the same java thread. This lock is needed
 357 // to prevent compiledVFrames from trying to add deferred updates
 358 // to the thread simultaneously.
 359 //
 360 class VM_GetOrSetLocal : public VM_Operation {
 361  protected:
 362   JavaThread* _thread;
 363   JavaThread* _calling_thread;
 364   jint        _depth;
 365   jint        _index;
 366   BasicType   _type;
 367   jvalue      _value;
 368   javaVFrame* _jvf;
 369   bool        _set;
 370 
 371   // It is possible to get the receiver out of a non-static native wrapper
 372   // frame.  Use VM_GetReceiver to do this.
 373   virtual bool getting_receiver() const { return false; }
 374 
 375   jvmtiError  _result;
 376 
 377   vframe* get_vframe();
 378   javaVFrame* get_java_vframe();
 379   bool check_slot_type(javaVFrame* vf);
 380 
 381 public:
 382   // Constructor for non-object getter
 383   VM_GetOrSetLocal(JavaThread* thread, jint depth, jint index, BasicType type);
 384 
 385   // Constructor for object or non-object setter
 386   VM_GetOrSetLocal(JavaThread* thread, jint depth, jint index, BasicType type, jvalue value);
 387 
 388   // Constructor for object getter
 389   VM_GetOrSetLocal(JavaThread* thread, JavaThread* calling_thread, jint depth,
 390                    int index);
 391 
 392   VMOp_Type type() const { return VMOp_GetOrSetLocal; }
 393   jvalue value()         { return _value; }
 394   jvmtiError result()    { return _result; }
 395 
 396   bool doit_prologue();
 397   void doit();
 398   bool allow_nested_vm_operations() const;
 399   const char* name() const                       { return "get/set locals"; }
 400 
 401   // Check that the klass is assignable to a type with the given signature.
 402   static bool is_assignable(const char* ty_sign, Klass* klass, Thread* thread);
 403 };
 404 
 405 class VM_GetReceiver : public VM_GetOrSetLocal {
 406  protected:
 407   virtual bool getting_receiver() const { return true; }
 408 
 409  public:
 410   VM_GetReceiver(JavaThread* thread, JavaThread* calling_thread, jint depth);
 411   const char* name() const                       { return "get receiver"; }
 412 };
 413 
 414 
 415 ///////////////////////////////////////////////////////////////
 416 //
 417 // class JvmtiSuspendControl
 418 //
 419 // Convenience routines for suspending and resuming threads.
 420 //
 421 // All attempts by JVMTI to suspend and resume threads must go through the
 422 // JvmtiSuspendControl interface.
 423 //
 424 // methods return true if successful
 425 //
 426 class JvmtiSuspendControl : public AllStatic {
 427 public:
 428   // suspend the thread, taking it to a safepoint
 429   static bool suspend(JavaThread *java_thread);
 430   // resume the thread
 431   static bool resume(JavaThread *java_thread);
 432 
 433   static void print();
 434 };
 435 
 436 
 437 /**
 438  * When a thread (such as the compiler thread or VM thread) cannot post a
 439  * JVMTI event itself because the event needs to be posted from a Java
 440  * thread, then it can defer the event to the Service thread for posting.
 441  * The information needed to post the event is encapsulated into this class
 442  * and then enqueued onto the JvmtiDeferredEventQueue, where the Service
 443  * thread will pick it up and post it.
 444  *
 445  * This is currently only used for posting compiled-method-load and unload
 446  * events, which we don't want posted from the compiler thread.
 447  */
 448 class JvmtiDeferredEvent VALUE_OBJ_CLASS_SPEC {
 449   friend class JvmtiDeferredEventQueue;
 450  private:
 451   typedef enum {
 452     TYPE_NONE,
 453     TYPE_COMPILED_METHOD_LOAD,
 454     TYPE_COMPILED_METHOD_UNLOAD,
 455     TYPE_DYNAMIC_CODE_GENERATED
 456   } Type;
 457 
 458   Type _type;
 459   union {
 460     nmethod* compiled_method_load;
 461     struct {
 462       nmethod* nm;
 463       jmethodID method_id;
 464       const void* code_begin;
 465     } compiled_method_unload;
 466     struct {
 467       const char* name;
 468       const void* code_begin;
 469       const void* code_end;
 470     } dynamic_code_generated;
 471   } _event_data;
 472 
 473   JvmtiDeferredEvent(Type t) : _type(t) {}
 474 
 475  public:
 476 
 477   JvmtiDeferredEvent() : _type(TYPE_NONE) {}
 478 
 479   // Factory methods
 480   static JvmtiDeferredEvent compiled_method_load_event(nmethod* nm)
 481     NOT_JVMTI_RETURN_(JvmtiDeferredEvent());
 482   static JvmtiDeferredEvent compiled_method_unload_event(nmethod* nm,
 483       jmethodID id, const void* code) NOT_JVMTI_RETURN_(JvmtiDeferredEvent());
 484   static JvmtiDeferredEvent dynamic_code_generated_event(
 485       const char* name, const void* begin, const void* end)
 486           NOT_JVMTI_RETURN_(JvmtiDeferredEvent());
 487 
 488   // Actually posts the event.
 489   void post() NOT_JVMTI_RETURN;
 490 };
 491 
 492 /**
 493  * Events enqueued on this queue wake up the Service thread which dequeues
 494  * and posts the events.  The Service_lock is required to be held
 495  * when operating on the queue (except for the "pending" events).
 496  */
 497 class JvmtiDeferredEventQueue : AllStatic {
 498   friend class JvmtiDeferredEvent;
 499  private:
 500   class QueueNode : public CHeapObj<mtInternal> {
 501    private:
 502     JvmtiDeferredEvent _event;
 503     QueueNode* _next;
 504 
 505    public:
 506     QueueNode(const JvmtiDeferredEvent& event)
 507       : _event(event), _next(NULL) {}
 508 
 509     const JvmtiDeferredEvent& event() const { return _event; }
 510     QueueNode* next() const { return _next; }
 511 
 512     void set_next(QueueNode* next) { _next = next; }
 513   };
 514 
 515   static QueueNode* _queue_head;             // Hold Service_lock to access
 516   static QueueNode* _queue_tail;             // Hold Service_lock to access
 517   static volatile QueueNode* _pending_list;  // Uses CAS for read/update
 518 
 519   // Transfers events from the _pending_list to the _queue.
 520   static void process_pending_events() NOT_JVMTI_RETURN;
 521 
 522  public:
 523   // Must be holding Service_lock when calling these
 524   static bool has_events() NOT_JVMTI_RETURN_(false);
 525   static void enqueue(const JvmtiDeferredEvent& event) NOT_JVMTI_RETURN;
 526   static JvmtiDeferredEvent dequeue() NOT_JVMTI_RETURN_(JvmtiDeferredEvent());
 527 
 528   // Used to enqueue events without using a lock, for times (such as during
 529   // safepoint) when we can't or don't want to lock the Service_lock.
 530   //
 531   // Events will be held off to the side until there's a call to
 532   // dequeue(), enqueue(), or process_pending_events() (all of which require
 533   // the holding of the Service_lock), and will be enqueued at that time.
 534   static void add_pending_event(const JvmtiDeferredEvent&) NOT_JVMTI_RETURN;
 535 };
 536 
 537 // Utility macro that checks for NULL pointers:
 538 #define NULL_CHECK(X, Y) if ((X) == NULL) { return (Y); }
 539 
 540 #endif // SHARE_VM_PRIMS_JVMTIIMPL_HPP