1 /*
   2  * Copyright (c) 1999, 2011, 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 #ifndef JVMTI_KERNEL
  29 
  30 #include "classfile/systemDictionary.hpp"
  31 #include "jvmtifiles/jvmti.h"
  32 #include "oops/objArrayOop.hpp"
  33 #include "prims/jvmtiEnvThreadState.hpp"
  34 #include "prims/jvmtiEventController.hpp"
  35 #include "prims/jvmtiTrace.hpp"
  36 #include "prims/jvmtiUtil.hpp"
  37 #include "runtime/stackValueCollection.hpp"
  38 #include "runtime/vm_operations.hpp"
  39 
  40 //
  41 // Forward Declarations
  42 //
  43 
  44 class JvmtiBreakpoint;
  45 class JvmtiBreakpoints;
  46 
  47 
  48 ///////////////////////////////////////////////////////////////
  49 //
  50 // class GrowableCache, GrowableElement
  51 // Used by              : JvmtiBreakpointCache
  52 // Used by JVMTI methods: none directly.
  53 //
  54 // GrowableCache is a permanent CHeap growable array of <GrowableElement *>
  55 //
  56 // In addition, the GrowableCache maintains a NULL terminated cache array of type address
  57 // that's created from the element array using the function:
  58 //     address GrowableElement::getCacheValue().
  59 //
  60 // Whenever the GrowableArray changes size, the cache array gets recomputed into a new C_HEAP allocated
  61 // block of memory. Additionally, every time the cache changes its position in memory, the
  62 //    void (*_listener_fun)(void *this_obj, address* cache)
  63 // gets called with the cache's new address. This gives the user of the GrowableCache a callback
  64 // to update its pointer to the address cache.
  65 //
  66 
  67 class GrowableElement : public CHeapObj {
  68 public:
  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 };
  75 
  76 class GrowableCache VALUE_OBJ_CLASS_SPEC {
  77 
  78 private:
  79   // Object pointer passed into cache & listener functions.
  80   void *_this_obj;
  81 
  82   // Array of elements in the collection
  83   GrowableArray<GrowableElement *> *_elements;
  84 
  85   // Parallel array of cached values
  86   address *_cache;
  87 
  88   // Listener for changes to the _cache field.
  89   // Called whenever the _cache field has it's value changed
  90   // (but NOT when cached elements are recomputed).
  91   void (*_listener_fun)(void *, address*);
  92 
  93   static bool equals(void *, GrowableElement *);
  94 
  95   // recache all elements after size change, notify listener
  96   void recache();
  97 
  98 public:
  99    GrowableCache();
 100    ~GrowableCache();
 101 
 102   void initialize(void *this_obj, void listener_fun(void *, address*) );
 103 
 104   // number of elements in the collection
 105   int length();
 106   // get the value of the index element in the collection
 107   GrowableElement* at(int index);
 108   // find the index of the element, -1 if it doesn't exist
 109   int find(GrowableElement* e);
 110   // append a copy of the element to the end of the collection, notify listener
 111   void append(GrowableElement* e);
 112   // insert a copy of the element using lessthan(), notify listener
 113   void insert(GrowableElement* e);
 114   // remove the element at index, notify listener
 115   void remove (int index);
 116   // clear out all elements and release all heap space, notify listener
 117   void clear();
 118   // apply f to every element and update the cache
 119   void oops_do(OopClosure* f);
 120   // update the cache after a full gc
 121   void gc_epilogue();
 122 };
 123 
 124 
 125 ///////////////////////////////////////////////////////////////
 126 //
 127 // class JvmtiBreakpointCache
 128 // Used by              : JvmtiBreakpoints
 129 // Used by JVMTI methods: none directly.
 130 // Note   : typesafe wrapper for GrowableCache of JvmtiBreakpoint
 131 //
 132 
 133 class JvmtiBreakpointCache : public CHeapObj {
 134 
 135 private:
 136   GrowableCache _cache;
 137 
 138 public:
 139   JvmtiBreakpointCache()  {}
 140   ~JvmtiBreakpointCache() {}
 141 
 142   void initialize(void *this_obj, void listener_fun(void *, address*) ) {
 143     _cache.initialize(this_obj,listener_fun);
 144   }
 145 
 146   int length()                          { return _cache.length(); }
 147   JvmtiBreakpoint& at(int index)        { return (JvmtiBreakpoint&) *(_cache.at(index)); }
 148   int find(JvmtiBreakpoint& e)          { return _cache.find((GrowableElement *) &e); }
 149   void append(JvmtiBreakpoint& e)       { _cache.append((GrowableElement *) &e); }
 150   void remove (int index)               { _cache.remove(index); }
 151   void clear()                          { _cache.clear(); }
 152   void oops_do(OopClosure* f)           { _cache.oops_do(f); }
 153   void gc_epilogue()                    { _cache.gc_epilogue(); }
 154 };
 155 
 156 
 157 ///////////////////////////////////////////////////////////////
 158 //
 159 // class JvmtiBreakpoint
 160 // Used by              : JvmtiBreakpoints
 161 // Used by JVMTI methods: SetBreakpoint, ClearBreakpoint, ClearAllBreakpoints
 162 // Note: Extends GrowableElement for use in a GrowableCache
 163 //
 164 // A JvmtiBreakpoint describes a location (class, method, bci) to break at.
 165 //
 166 
 167 typedef void (methodOopDesc::*method_action)(int _bci);
 168 
 169 class JvmtiBreakpoint : public GrowableElement {
 170 private:
 171   methodOop             _method;
 172   int                   _bci;
 173   Bytecodes::Code       _orig_bytecode;
 174 
 175 public:
 176   JvmtiBreakpoint();
 177   JvmtiBreakpoint(methodOop m_method, jlocation location);
 178   bool equals(JvmtiBreakpoint& bp);
 179   bool lessThan(JvmtiBreakpoint &bp);
 180   void copy(JvmtiBreakpoint& bp);
 181   bool is_valid();
 182   address getBcp();
 183   void each_method_version_do(method_action meth_act);
 184   void set();
 185   void clear();
 186   void print();
 187 
 188   methodOop method() { return _method; }
 189 
 190   // GrowableElement implementation
 191   address getCacheValue()         { return getBcp(); }
 192   bool lessThan(GrowableElement* e) { Unimplemented(); return false; }
 193   bool equals(GrowableElement* e) { return equals((JvmtiBreakpoint&) *e); }
 194   void oops_do(OopClosure* f)     { f->do_oop((oop *) &_method); }
 195   GrowableElement *clone()        {
 196     JvmtiBreakpoint *bp = new JvmtiBreakpoint();
 197     bp->copy(*this);
 198     return bp;
 199   }
 200 };
 201 
 202 
 203 ///////////////////////////////////////////////////////////////
 204 //
 205 // class VM_ChangeBreakpoints
 206 // Used by              : JvmtiBreakpoints
 207 // Used by JVMTI methods: none directly.
 208 // Note: A Helper class.
 209 //
 210 // VM_ChangeBreakpoints implements a VM_Operation for ALL modifications to the JvmtiBreakpoints class.
 211 //
 212 
 213 class VM_ChangeBreakpoints : public VM_Operation {
 214 private:
 215   JvmtiBreakpoints* _breakpoints;
 216   int               _operation;
 217   JvmtiBreakpoint*  _bp;
 218 
 219 public:
 220   enum { SET_BREAKPOINT=0, CLEAR_BREAKPOINT=1, CLEAR_ALL_BREAKPOINT=2 };
 221 
 222   VM_ChangeBreakpoints(JvmtiBreakpoints* breakpoints, int operation) {
 223     _breakpoints = breakpoints;
 224     _bp = NULL;
 225     _operation = operation;
 226     assert(breakpoints != NULL, "breakpoints != NULL");
 227     assert(operation == CLEAR_ALL_BREAKPOINT, "unknown breakpoint operation");
 228   }
 229   VM_ChangeBreakpoints(JvmtiBreakpoints* breakpoints, int operation, JvmtiBreakpoint *bp) {
 230     _breakpoints = breakpoints;
 231     _bp = bp;
 232     _operation = operation;
 233     assert(breakpoints != NULL, "breakpoints != NULL");
 234     assert(bp != NULL, "bp != NULL");
 235     assert(operation == SET_BREAKPOINT || operation == CLEAR_BREAKPOINT , "unknown breakpoint operation");
 236   }
 237 
 238   VMOp_Type type() const { return VMOp_ChangeBreakpoints; }
 239   void doit();
 240   void oops_do(OopClosure* f);
 241 };
 242 
 243 
 244 ///////////////////////////////////////////////////////////////
 245 //
 246 // class JvmtiBreakpoints
 247 // Used by              : JvmtiCurrentBreakpoints
 248 // Used by JVMTI methods: none directly
 249 // Note: A Helper class
 250 //
 251 // JvmtiBreakpoints is a GrowableCache of JvmtiBreakpoint.
 252 // All changes to the GrowableCache occur at a safepoint using VM_ChangeBreakpoints.
 253 //
 254 // Because _bps is only modified at safepoints, its possible to always use the
 255 // cached byte code pointers from _bps without doing any synchronization (see JvmtiCurrentBreakpoints).
 256 //
 257 // It would be possible to make JvmtiBreakpoints a static class, but I've made it
 258 // CHeap allocated to emphasize its similarity to JvmtiFramePops.
 259 //
 260 
 261 class JvmtiBreakpoints : public CHeapObj {
 262 private:
 263 
 264   JvmtiBreakpointCache _bps;
 265 
 266   // These should only be used by VM_ChangeBreakpoints
 267   // to insure they only occur at safepoints.
 268   // Todo: add checks for safepoint
 269   friend class VM_ChangeBreakpoints;
 270   void set_at_safepoint(JvmtiBreakpoint& bp);
 271   void clear_at_safepoint(JvmtiBreakpoint& bp);
 272   void clearall_at_safepoint();
 273 
 274   static void do_element(GrowableElement *e);
 275 
 276 public:
 277   JvmtiBreakpoints(void listener_fun(void *, address *));
 278   ~JvmtiBreakpoints();
 279 
 280   int length();
 281   void oops_do(OopClosure* f);
 282   void print();
 283 
 284   int  set(JvmtiBreakpoint& bp);
 285   int  clear(JvmtiBreakpoint& bp);
 286   void clearall_in_class_at_safepoint(klassOop klass);
 287   void clearall();
 288   void gc_epilogue();
 289 };
 290 
 291 
 292 ///////////////////////////////////////////////////////////////
 293 //
 294 // class JvmtiCurrentBreakpoints
 295 //
 296 // A static wrapper class for the JvmtiBreakpoints that provides:
 297 // 1. a fast inlined function to check if a byte code pointer is a breakpoint (is_breakpoint).
 298 // 2. a function for lazily creating the JvmtiBreakpoints class (this is not strictly necessary,
 299 //    but I'm copying the code from JvmtiThreadState which needs to lazily initialize
 300 //    JvmtiFramePops).
 301 // 3. An oops_do entry point for GC'ing the breakpoint array.
 302 //
 303 
 304 class JvmtiCurrentBreakpoints : public AllStatic {
 305 
 306 private:
 307 
 308   // Current breakpoints, lazily initialized by get_jvmti_breakpoints();
 309   static JvmtiBreakpoints *_jvmti_breakpoints;
 310 
 311   // NULL terminated cache of byte-code pointers corresponding to current breakpoints.
 312   // Updated only at safepoints (with listener_fun) when the cache is moved.
 313   // It exists only to make is_breakpoint fast.
 314   static address          *_breakpoint_list;
 315   static inline void set_breakpoint_list(address *breakpoint_list) { _breakpoint_list = breakpoint_list; }
 316   static inline address *get_breakpoint_list()                     { return _breakpoint_list; }
 317 
 318   // Listener for the GrowableCache in _jvmti_breakpoints, updates _breakpoint_list.
 319   static void listener_fun(void *this_obj, address *cache);
 320 
 321 public:
 322   static void initialize();
 323   static void destroy();
 324 
 325   // lazily create _jvmti_breakpoints and _breakpoint_list
 326   static JvmtiBreakpoints& get_jvmti_breakpoints();
 327 
 328   // quickly test whether the bcp matches a cached breakpoint in the list
 329   static inline bool is_breakpoint(address bcp);
 330 
 331   static void oops_do(OopClosure* f);
 332   static void gc_epilogue();
 333 };
 334 
 335 // quickly test whether the bcp matches a cached breakpoint in the list
 336 bool JvmtiCurrentBreakpoints::is_breakpoint(address bcp) {
 337     address *bps = get_breakpoint_list();
 338     if (bps == NULL) return false;
 339     for ( ; (*bps) != NULL; bps++) {
 340       if ((*bps) == bcp) return true;
 341     }
 342     return false;
 343 }
 344 
 345 ///////////////////////////////////////////////////////////////
 346 // The get/set local operations must only be done by the VM thread
 347 // because the interpreter version needs to access oop maps, which can
 348 // only safely be done by the VM thread
 349 //
 350 // I'm told that in 1.5 oop maps are now protected by a lock and
 351 // we could get rid of the VM op
 352 // However if the VM op is removed then the target thread must
 353 // be suspended AND a lock will be needed to prevent concurrent
 354 // setting of locals to the same java thread. This lock is needed
 355 // to prevent compiledVFrames from trying to add deferred updates
 356 // to the thread simultaneously.
 357 //
 358 class VM_GetOrSetLocal : public VM_Operation {
 359  protected:
 360   JavaThread* _thread;
 361   JavaThread* _calling_thread;
 362   jint        _depth;
 363   jint        _index;
 364   BasicType   _type;
 365   jvalue      _value;
 366   javaVFrame* _jvf;
 367   bool        _set;
 368 
 369   // It is possible to get the receiver out of a non-static native wrapper
 370   // frame.  Use VM_GetReceiver to do this.
 371   virtual bool getting_receiver() const { return false; }
 372 
 373   jvmtiError  _result;
 374 
 375   vframe* get_vframe();
 376   javaVFrame* get_java_vframe();
 377   bool check_slot_type(javaVFrame* vf);
 378 
 379 public:
 380   // Constructor for non-object getter
 381   VM_GetOrSetLocal(JavaThread* thread, jint depth, jint index, BasicType type);
 382 
 383   // Constructor for object or non-object setter
 384   VM_GetOrSetLocal(JavaThread* thread, jint depth, jint index, BasicType type, jvalue value);
 385 
 386   // Constructor for object getter
 387   VM_GetOrSetLocal(JavaThread* thread, JavaThread* calling_thread, jint depth,
 388                    int index);
 389 
 390   VMOp_Type type() const { return VMOp_GetOrSetLocal; }
 391   jvalue value()         { return _value; }
 392   jvmtiError result()    { return _result; }
 393 
 394   bool doit_prologue();
 395   void doit();
 396   bool allow_nested_vm_operations() const;
 397   const char* name() const                       { return "get/set locals"; }
 398 
 399   // Check that the klass is assignable to a type with the given signature.
 400   static bool is_assignable(const char* ty_sign, Klass* klass, Thread* thread);
 401 };
 402 
 403 class VM_GetReceiver : public VM_GetOrSetLocal {
 404  protected:
 405   virtual bool getting_receiver() const { return true; }
 406 
 407  public:
 408   VM_GetReceiver(JavaThread* thread, JavaThread* calling_thread, jint depth);
 409   const char* name() const                       { return "get receiver"; }
 410 };
 411 
 412 
 413 ///////////////////////////////////////////////////////////////
 414 //
 415 // class JvmtiSuspendControl
 416 //
 417 // Convenience routines for suspending and resuming threads.
 418 //
 419 // All attempts by JVMTI to suspend and resume threads must go through the
 420 // JvmtiSuspendControl interface.
 421 //
 422 // methods return true if successful
 423 //
 424 class JvmtiSuspendControl : public AllStatic {
 425 public:
 426   // suspend the thread, taking it to a safepoint
 427   static bool suspend(JavaThread *java_thread);
 428   // resume the thread
 429   static bool resume(JavaThread *java_thread);
 430 
 431   static void print();
 432 };
 433 
 434 #endif // !JVMTI_KERNEL
 435 
 436 /**
 437  * When a thread (such as the compiler thread or VM thread) cannot post a
 438  * JVMTI event itself because the event needs to be posted from a Java
 439  * thread, then it can defer the event to the Service thread for posting.
 440  * The information needed to post the event is encapsulated into this class
 441  * and then enqueued onto the JvmtiDeferredEventQueue, where the Service
 442  * thread will pick it up and post it.
 443  *
 444  * This is currently only used for posting compiled-method-load and unload
 445  * events, which we don't want posted from the compiler thread.
 446  */
 447 class JvmtiDeferredEvent VALUE_OBJ_CLASS_SPEC {
 448   friend class JvmtiDeferredEventQueue;
 449  private:
 450   typedef enum {
 451     TYPE_NONE,
 452     TYPE_COMPILED_METHOD_LOAD,
 453     TYPE_COMPILED_METHOD_UNLOAD,
 454     TYPE_DYNAMIC_CODE_GENERATED
 455   } Type;
 456 
 457   Type _type;
 458   union {
 459     nmethod* compiled_method_load;
 460     struct {
 461       jmethodID method_id;
 462       const void* code_begin;
 463     } compiled_method_unload;
 464     struct {
 465       const char* name;
 466       const void* code_begin;
 467       const void* code_end;
 468     } dynamic_code_generated;
 469   } _event_data;
 470 
 471   JvmtiDeferredEvent(Type t) : _type(t) {}
 472 
 473  public:
 474 
 475   JvmtiDeferredEvent() : _type(TYPE_NONE) {}
 476 
 477   // Factory methods
 478   static JvmtiDeferredEvent compiled_method_load_event(nmethod* nm)
 479     KERNEL_RETURN_(JvmtiDeferredEvent());
 480   static JvmtiDeferredEvent compiled_method_unload_event(
 481       jmethodID id, const void* code) KERNEL_RETURN_(JvmtiDeferredEvent());
 482   static JvmtiDeferredEvent dynamic_code_generated_event(
 483       const char* name, const void* begin, const void* end)
 484           KERNEL_RETURN_(JvmtiDeferredEvent());
 485 
 486   // Actually posts the event.
 487   void post() KERNEL_RETURN;
 488 };
 489 
 490 /**
 491  * Events enqueued on this queue wake up the Service thread which dequeues
 492  * and posts the events.  The Service_lock is required to be held
 493  * when operating on the queue (except for the "pending" events).
 494  */
 495 class JvmtiDeferredEventQueue : AllStatic {
 496   friend class JvmtiDeferredEvent;
 497  private:
 498   class QueueNode : public CHeapObj {
 499    private:
 500     JvmtiDeferredEvent _event;
 501     QueueNode* _next;
 502 
 503    public:
 504     QueueNode(const JvmtiDeferredEvent& event)
 505       : _event(event), _next(NULL) {}
 506 
 507     const JvmtiDeferredEvent& event() const { return _event; }
 508     QueueNode* next() const { return _next; }
 509 
 510     void set_next(QueueNode* next) { _next = next; }
 511   };
 512 
 513   static QueueNode* _queue_head;             // Hold Service_lock to access
 514   static QueueNode* _queue_tail;             // Hold Service_lock to access
 515   static volatile QueueNode* _pending_list;  // Uses CAS for read/update
 516 
 517   // Transfers events from the _pending_list to the _queue.
 518   static void process_pending_events() KERNEL_RETURN;
 519 
 520  public:
 521   // Must be holding Service_lock when calling these
 522   static bool has_events() KERNEL_RETURN_(false);
 523   static void enqueue(const JvmtiDeferredEvent& event) KERNEL_RETURN;
 524   static JvmtiDeferredEvent dequeue() KERNEL_RETURN_(JvmtiDeferredEvent());
 525 
 526   // Used to enqueue events without using a lock, for times (such as during
 527   // safepoint) when we can't or don't want to lock the Service_lock.
 528   //
 529   // Events will be held off to the side until there's a call to
 530   // dequeue(), enqueue(), or process_pending_events() (all of which require
 531   // the holding of the Service_lock), and will be enqueued at that time.
 532   static void add_pending_event(const JvmtiDeferredEvent&) KERNEL_RETURN;
 533 };
 534 
 535 // Utility macro that checks for NULL pointers:
 536 #define NULL_CHECK(X, Y) if ((X) == NULL) { return (Y); }
 537 
 538 #endif // SHARE_VM_PRIMS_JVMTIIMPL_HPP