1 /*
   2  * Copyright (c) 2003, 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 #include "precompiled.hpp"
  26 #include "classfile/systemDictionary.hpp"
  27 #include "interpreter/interpreter.hpp"
  28 #include "jvmtifiles/jvmtiEnv.hpp"
  29 #include "memory/resourceArea.hpp"
  30 #include "oops/instanceKlass.hpp"
  31 #include "prims/jvmtiAgentThread.hpp"
  32 #include "prims/jvmtiEventController.inline.hpp"
  33 #include "prims/jvmtiImpl.hpp"
  34 #include "prims/jvmtiRedefineClasses.hpp"
  35 #include "runtime/atomic.hpp"
  36 #include "runtime/deoptimization.hpp"
  37 #include "runtime/handles.hpp"
  38 #include "runtime/handles.inline.hpp"
  39 #include "runtime/interfaceSupport.hpp"
  40 #include "runtime/javaCalls.hpp"
  41 #include "runtime/os.hpp"
  42 #include "runtime/serviceThread.hpp"
  43 #include "runtime/signature.hpp"
  44 #include "runtime/thread.inline.hpp"
  45 #include "runtime/vframe.hpp"
  46 #include "runtime/vframe_hp.hpp"
  47 #include "runtime/vm_operations.hpp"
  48 #include "utilities/exceptions.hpp"
  49 
  50 //
  51 // class JvmtiAgentThread
  52 //
  53 // JavaThread used to wrap a thread started by an agent
  54 // using the JVMTI method RunAgentThread.
  55 //
  56 
  57 JvmtiAgentThread::JvmtiAgentThread(JvmtiEnv* env, jvmtiStartFunction start_fn, const void *start_arg)
  58     : JavaThread(start_function_wrapper) {
  59     _env = env;
  60     _start_fn = start_fn;
  61     _start_arg = start_arg;
  62 }
  63 
  64 void
  65 JvmtiAgentThread::start_function_wrapper(JavaThread *thread, TRAPS) {
  66     // It is expected that any Agent threads will be created as
  67     // Java Threads.  If this is the case, notification of the creation
  68     // of the thread is given in JavaThread::thread_main().
  69     assert(thread->is_Java_thread(), "debugger thread should be a Java Thread");
  70     assert(thread == JavaThread::current(), "sanity check");
  71 
  72     JvmtiAgentThread *dthread = (JvmtiAgentThread *)thread;
  73     dthread->call_start_function();
  74 }
  75 
  76 void
  77 JvmtiAgentThread::call_start_function() {
  78     ThreadToNativeFromVM transition(this);
  79     _start_fn(_env->jvmti_external(), jni_environment(), (void*)_start_arg);
  80 }
  81 
  82 
  83 //
  84 // class GrowableCache - private methods
  85 //
  86 
  87 void GrowableCache::recache() {
  88   int len = _elements->length();
  89 
  90   FREE_C_HEAP_ARRAY(address, _cache, mtInternal);
  91   _cache = NEW_C_HEAP_ARRAY(address,len+1, mtInternal);
  92 
  93   for (int i=0; i<len; i++) {
  94     _cache[i] = _elements->at(i)->getCacheValue();
  95     //
  96     // The cache entry has gone bad. Without a valid frame pointer
  97     // value, the entry is useless so we simply delete it in product
  98     // mode. The call to remove() will rebuild the cache again
  99     // without the bad entry.
 100     //
 101     if (_cache[i] == NULL) {
 102       assert(false, "cannot recache NULL elements");
 103       remove(i);
 104       return;
 105     }
 106   }
 107   _cache[len] = NULL;
 108 
 109   _listener_fun(_this_obj,_cache);
 110 }
 111 
 112 bool GrowableCache::equals(void* v, GrowableElement *e2) {
 113   GrowableElement *e1 = (GrowableElement *) v;
 114   assert(e1 != NULL, "e1 != NULL");
 115   assert(e2 != NULL, "e2 != NULL");
 116 
 117   return e1->equals(e2);
 118 }
 119 
 120 //
 121 // class GrowableCache - public methods
 122 //
 123 
 124 GrowableCache::GrowableCache() {
 125   _this_obj       = NULL;
 126   _listener_fun   = NULL;
 127   _elements       = NULL;
 128   _cache          = NULL;
 129 }
 130 
 131 GrowableCache::~GrowableCache() {
 132   clear();
 133   delete _elements;
 134   FREE_C_HEAP_ARRAY(address, _cache, mtInternal);
 135 }
 136 
 137 void GrowableCache::initialize(void *this_obj, void listener_fun(void *, address*) ) {
 138   _this_obj       = this_obj;
 139   _listener_fun   = listener_fun;
 140   _elements       = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<GrowableElement*>(5,true);
 141   recache();
 142 }
 143 
 144 // number of elements in the collection
 145 int GrowableCache::length() {
 146   return _elements->length();
 147 }
 148 
 149 // get the value of the index element in the collection
 150 GrowableElement* GrowableCache::at(int index) {
 151   GrowableElement *e = (GrowableElement *) _elements->at(index);
 152   assert(e != NULL, "e != NULL");
 153   return e;
 154 }
 155 
 156 int GrowableCache::find(GrowableElement* e) {
 157   return _elements->find(e, GrowableCache::equals);
 158 }
 159 
 160 // append a copy of the element to the end of the collection
 161 void GrowableCache::append(GrowableElement* e) {
 162   GrowableElement *new_e = e->clone();
 163   _elements->append(new_e);
 164   recache();
 165 }
 166 
 167 // insert a copy of the element using lessthan()
 168 void GrowableCache::insert(GrowableElement* e) {
 169   GrowableElement *new_e = e->clone();
 170   _elements->append(new_e);
 171 
 172   int n = length()-2;
 173   for (int i=n; i>=0; i--) {
 174     GrowableElement *e1 = _elements->at(i);
 175     GrowableElement *e2 = _elements->at(i+1);
 176     if (e2->lessThan(e1)) {
 177       _elements->at_put(i+1, e1);
 178       _elements->at_put(i,   e2);
 179     }
 180   }
 181 
 182   recache();
 183 }
 184 
 185 // remove the element at index
 186 void GrowableCache::remove (int index) {
 187   GrowableElement *e = _elements->at(index);
 188   assert(e != NULL, "e != NULL");
 189   _elements->remove(e);
 190   delete e;
 191   recache();
 192 }
 193 
 194 // clear out all elements, release all heap space and
 195 // let our listener know that things have changed.
 196 void GrowableCache::clear() {
 197   int len = _elements->length();
 198   for (int i=0; i<len; i++) {
 199     delete _elements->at(i);
 200   }
 201   _elements->clear();
 202   recache();
 203 }
 204 
 205 void GrowableCache::oops_do(OopClosure* f) {
 206   int len = _elements->length();
 207   for (int i=0; i<len; i++) {
 208     GrowableElement *e = _elements->at(i);
 209     e->oops_do(f);
 210   }
 211 }
 212 
 213 void GrowableCache::gc_epilogue() {
 214   int len = _elements->length();
 215   for (int i=0; i<len; i++) {
 216     _cache[i] = _elements->at(i)->getCacheValue();
 217   }
 218 }
 219 
 220 //
 221 // class JvmtiBreakpoint
 222 //
 223 
 224 JvmtiBreakpoint::JvmtiBreakpoint() {
 225   _method = NULL;
 226   _bci    = 0;
 227   _class_loader = NULL;
 228 #ifdef CHECK_UNHANDLED_OOPS
 229   // This one is always allocated with new, but check it just in case.
 230   Thread *thread = Thread::current();
 231   if (thread->is_in_stack((address)&_method)) {
 232     thread->allow_unhandled_oop((oop*)&_method);
 233   }
 234 #endif // CHECK_UNHANDLED_OOPS
 235 }
 236 
 237 JvmtiBreakpoint::JvmtiBreakpoint(Method* m_method, jlocation location) {
 238   _method        = m_method;
 239   _class_loader  = _method->method_holder()->class_loader_data()->class_loader();
 240   assert(_method != NULL, "_method != NULL");
 241   _bci           = (int) location;
 242   assert(_bci >= 0, "_bci >= 0");
 243 }
 244 
 245 void JvmtiBreakpoint::copy(JvmtiBreakpoint& bp) {
 246   _method   = bp._method;
 247   _bci      = bp._bci;
 248   _class_loader = bp._class_loader;
 249 }
 250 
 251 bool JvmtiBreakpoint::lessThan(JvmtiBreakpoint& bp) {
 252   Unimplemented();
 253   return false;
 254 }
 255 
 256 bool JvmtiBreakpoint::equals(JvmtiBreakpoint& bp) {
 257   return _method   == bp._method
 258     &&   _bci      == bp._bci;
 259 }
 260 
 261 bool JvmtiBreakpoint::is_valid() {
 262   // class loader can be NULL
 263   return _method != NULL &&
 264          _bci >= 0;
 265 }
 266 
 267 address JvmtiBreakpoint::getBcp() {
 268   return _method->bcp_from(_bci);
 269 }
 270 
 271 void JvmtiBreakpoint::each_method_version_do(method_action meth_act) {
 272   ((Method*)_method->*meth_act)(_bci);
 273 
 274   // add/remove breakpoint to/from versions of the method that
 275   // are EMCP. Directly or transitively obsolete methods are
 276   // not saved in the PreviousVersionInfo.
 277   Thread *thread = Thread::current();
 278   instanceKlassHandle ikh = instanceKlassHandle(thread, _method->method_holder());
 279   Symbol* m_name = _method->name();
 280   Symbol* m_signature = _method->signature();
 281 
 282   {
 283     ResourceMark rm(thread);
 284     // PreviousVersionInfo objects returned via PreviousVersionWalker
 285     // contain a GrowableArray of handles. We have to clean up the
 286     // GrowableArray _after_ the PreviousVersionWalker destructor
 287     // has destroyed the handles.
 288     {
 289       // search previous versions if they exist
 290       PreviousVersionWalker pvw((InstanceKlass *)ikh());
 291       for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
 292            pv_info != NULL; pv_info = pvw.next_previous_version()) {
 293         GrowableArray<methodHandle>* methods =
 294           pv_info->prev_EMCP_method_handles();
 295 
 296         if (methods == NULL) {
 297           // We have run into a PreviousVersion generation where
 298           // all methods were made obsolete during that generation's
 299           // RedefineClasses() operation. At the time of that
 300           // operation, all EMCP methods were flushed so we don't
 301           // have to go back any further.
 302           //
 303           // A NULL methods array is different than an empty methods
 304           // array. We cannot infer any optimizations about older
 305           // generations from an empty methods array for the current
 306           // generation.
 307           break;
 308         }
 309 
 310         for (int i = methods->length() - 1; i >= 0; i--) {
 311           methodHandle method = methods->at(i);
 312           // obsolete methods that are running are not deleted from
 313           // previous version array, but they are skipped here.
 314           if (!method->is_obsolete() &&
 315               method->name() == m_name &&
 316               method->signature() == m_signature) {
 317             RC_TRACE(0x00000800, ("%sing breakpoint in %s(%s)",
 318               meth_act == &Method::set_breakpoint ? "sett" : "clear",
 319               method->name()->as_C_string(),
 320               method->signature()->as_C_string()));
 321 
 322             ((Method*)method()->*meth_act)(_bci);
 323             break;
 324           }
 325         }
 326       }
 327     } // pvw is cleaned up
 328   } // rm is cleaned up
 329 }
 330 
 331 void JvmtiBreakpoint::set() {
 332   each_method_version_do(&Method::set_breakpoint);
 333 }
 334 
 335 void JvmtiBreakpoint::clear() {
 336   each_method_version_do(&Method::clear_breakpoint);
 337 }
 338 
 339 void JvmtiBreakpoint::print() {
 340 #ifndef PRODUCT
 341   const char *class_name  = (_method == NULL) ? "NULL" : _method->klass_name()->as_C_string();
 342   const char *method_name = (_method == NULL) ? "NULL" : _method->name()->as_C_string();
 343 
 344   tty->print("Breakpoint(%s,%s,%d,%p)",class_name, method_name, _bci, getBcp());
 345 #endif
 346 }
 347 
 348 
 349 //
 350 // class VM_ChangeBreakpoints
 351 //
 352 // Modify the Breakpoints data structure at a safepoint
 353 //
 354 
 355 void VM_ChangeBreakpoints::doit() {
 356   switch (_operation) {
 357   case SET_BREAKPOINT:
 358     _breakpoints->set_at_safepoint(*_bp);
 359     break;
 360   case CLEAR_BREAKPOINT:
 361     _breakpoints->clear_at_safepoint(*_bp);
 362     break;
 363   default:
 364     assert(false, "Unknown operation");
 365   }
 366 }
 367 
 368 void VM_ChangeBreakpoints::oops_do(OopClosure* f) {
 369   // The JvmtiBreakpoints in _breakpoints will be visited via
 370   // JvmtiExport::oops_do.
 371   if (_bp != NULL) {
 372     _bp->oops_do(f);
 373   }
 374 }
 375 
 376 //
 377 // class JvmtiBreakpoints
 378 //
 379 // a JVMTI internal collection of JvmtiBreakpoint
 380 //
 381 
 382 JvmtiBreakpoints::JvmtiBreakpoints(void listener_fun(void *,address *)) {
 383   _bps.initialize(this,listener_fun);
 384 }
 385 
 386 JvmtiBreakpoints:: ~JvmtiBreakpoints() {}
 387 
 388 void  JvmtiBreakpoints::oops_do(OopClosure* f) {
 389   _bps.oops_do(f);
 390 }
 391 
 392 void JvmtiBreakpoints::gc_epilogue() {
 393   _bps.gc_epilogue();
 394 }
 395 
 396 void  JvmtiBreakpoints::print() {
 397 #ifndef PRODUCT
 398   ResourceMark rm;
 399 
 400   int n = _bps.length();
 401   for (int i=0; i<n; i++) {
 402     JvmtiBreakpoint& bp = _bps.at(i);
 403     tty->print("%d: ", i);
 404     bp.print();
 405     tty->print_cr("");
 406   }
 407 #endif
 408 }
 409 
 410 
 411 void JvmtiBreakpoints::set_at_safepoint(JvmtiBreakpoint& bp) {
 412   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 413 
 414   int i = _bps.find(bp);
 415   if (i == -1) {
 416     _bps.append(bp);
 417     bp.set();
 418   }
 419 }
 420 
 421 void JvmtiBreakpoints::clear_at_safepoint(JvmtiBreakpoint& bp) {
 422   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 423 
 424   int i = _bps.find(bp);
 425   if (i != -1) {
 426     _bps.remove(i);
 427     bp.clear();
 428   }
 429 }
 430 
 431 int JvmtiBreakpoints::length() { return _bps.length(); }
 432 
 433 int JvmtiBreakpoints::set(JvmtiBreakpoint& bp) {
 434   if ( _bps.find(bp) != -1) {
 435      return JVMTI_ERROR_DUPLICATE;
 436   }
 437   VM_ChangeBreakpoints set_breakpoint(VM_ChangeBreakpoints::SET_BREAKPOINT, &bp);
 438   VMThread::execute(&set_breakpoint);
 439   return JVMTI_ERROR_NONE;
 440 }
 441 
 442 int JvmtiBreakpoints::clear(JvmtiBreakpoint& bp) {
 443   if ( _bps.find(bp) == -1) {
 444      return JVMTI_ERROR_NOT_FOUND;
 445   }
 446 
 447   VM_ChangeBreakpoints clear_breakpoint(VM_ChangeBreakpoints::CLEAR_BREAKPOINT, &bp);
 448   VMThread::execute(&clear_breakpoint);
 449   return JVMTI_ERROR_NONE;
 450 }
 451 
 452 void JvmtiBreakpoints::clearall_in_class_at_safepoint(Klass* klass) {
 453   bool changed = true;
 454   // We are going to run thru the list of bkpts
 455   // and delete some.  This deletion probably alters
 456   // the list in some implementation defined way such
 457   // that when we delete entry i, the next entry might
 458   // no longer be at i+1.  To be safe, each time we delete
 459   // an entry, we'll just start again from the beginning.
 460   // We'll stop when we make a pass thru the whole list without
 461   // deleting anything.
 462   while (changed) {
 463     int len = _bps.length();
 464     changed = false;
 465     for (int i = 0; i < len; i++) {
 466       JvmtiBreakpoint& bp = _bps.at(i);
 467       if (bp.method()->method_holder() == klass) {
 468         bp.clear();
 469         _bps.remove(i);
 470         // This changed 'i' so we have to start over.
 471         changed = true;
 472         break;
 473       }
 474     }
 475   }
 476 }
 477 
 478 //
 479 // class JvmtiCurrentBreakpoints
 480 //
 481 
 482 JvmtiBreakpoints *JvmtiCurrentBreakpoints::_jvmti_breakpoints  = NULL;
 483 address *         JvmtiCurrentBreakpoints::_breakpoint_list    = NULL;
 484 
 485 
 486 JvmtiBreakpoints& JvmtiCurrentBreakpoints::get_jvmti_breakpoints() {
 487   if (_jvmti_breakpoints != NULL) return (*_jvmti_breakpoints);
 488   _jvmti_breakpoints = new JvmtiBreakpoints(listener_fun);
 489   assert(_jvmti_breakpoints != NULL, "_jvmti_breakpoints != NULL");
 490   return (*_jvmti_breakpoints);
 491 }
 492 
 493 void  JvmtiCurrentBreakpoints::listener_fun(void *this_obj, address *cache) {
 494   JvmtiBreakpoints *this_jvmti = (JvmtiBreakpoints *) this_obj;
 495   assert(this_jvmti != NULL, "this_jvmti != NULL");
 496 
 497   debug_only(int n = this_jvmti->length(););
 498   assert(cache[n] == NULL, "cache must be NULL terminated");
 499 
 500   set_breakpoint_list(cache);
 501 }
 502 
 503 
 504 void JvmtiCurrentBreakpoints::oops_do(OopClosure* f) {
 505   if (_jvmti_breakpoints != NULL) {
 506     _jvmti_breakpoints->oops_do(f);
 507   }
 508 }
 509 
 510 void JvmtiCurrentBreakpoints::gc_epilogue() {
 511   if (_jvmti_breakpoints != NULL) {
 512     _jvmti_breakpoints->gc_epilogue();
 513   }
 514 }
 515 
 516 ///////////////////////////////////////////////////////////////
 517 //
 518 // class VM_GetOrSetLocal
 519 //
 520 
 521 // Constructor for non-object getter
 522 VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, jint depth, int index, BasicType type)
 523   : _thread(thread)
 524   , _calling_thread(NULL)
 525   , _depth(depth)
 526   , _index(index)
 527   , _type(type)
 528   , _set(false)
 529   , _jvf(NULL)
 530   , _result(JVMTI_ERROR_NONE)
 531 {
 532 }
 533 
 534 // Constructor for object or non-object setter
 535 VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, jint depth, int index, BasicType type, jvalue value)
 536   : _thread(thread)
 537   , _calling_thread(NULL)
 538   , _depth(depth)
 539   , _index(index)
 540   , _type(type)
 541   , _value(value)
 542   , _set(true)
 543   , _jvf(NULL)
 544   , _result(JVMTI_ERROR_NONE)
 545 {
 546 }
 547 
 548 // Constructor for object getter
 549 VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, JavaThread* calling_thread, jint depth, int index)
 550   : _thread(thread)
 551   , _calling_thread(calling_thread)
 552   , _depth(depth)
 553   , _index(index)
 554   , _type(T_OBJECT)
 555   , _set(false)
 556   , _jvf(NULL)
 557   , _result(JVMTI_ERROR_NONE)
 558 {
 559 }
 560 
 561 vframe *VM_GetOrSetLocal::get_vframe() {
 562   if (!_thread->has_last_Java_frame()) {
 563     return NULL;
 564   }
 565   RegisterMap reg_map(_thread);
 566   vframe *vf = _thread->last_java_vframe(&reg_map);
 567   int d = 0;
 568   while ((vf != NULL) && (d < _depth)) {
 569     vf = vf->java_sender();
 570     d++;
 571   }
 572   return vf;
 573 }
 574 
 575 javaVFrame *VM_GetOrSetLocal::get_java_vframe() {
 576   vframe* vf = get_vframe();
 577   if (vf == NULL) {
 578     _result = JVMTI_ERROR_NO_MORE_FRAMES;
 579     return NULL;
 580   }
 581   javaVFrame *jvf = (javaVFrame*)vf;
 582 
 583   if (!vf->is_java_frame()) {
 584     _result = JVMTI_ERROR_OPAQUE_FRAME;
 585     return NULL;
 586   }
 587   return jvf;
 588 }
 589 
 590 // Check that the klass is assignable to a type with the given signature.
 591 // Another solution could be to use the function Klass::is_subtype_of(type).
 592 // But the type class can be forced to load/initialize eagerly in such a case.
 593 // This may cause unexpected consequences like CFLH or class-init JVMTI events.
 594 // It is better to avoid such a behavior.
 595 bool VM_GetOrSetLocal::is_assignable(const char* ty_sign, Klass* klass, Thread* thread) {
 596   assert(ty_sign != NULL, "type signature must not be NULL");
 597   assert(thread != NULL, "thread must not be NULL");
 598   assert(klass != NULL, "klass must not be NULL");
 599 
 600   int len = (int) strlen(ty_sign);
 601   if (ty_sign[0] == 'L' && ty_sign[len-1] == ';') { // Need pure class/interface name
 602     ty_sign++;
 603     len -= 2;
 604   }
 605   TempNewSymbol ty_sym = SymbolTable::new_symbol(ty_sign, len, thread);
 606   if (klass->name() == ty_sym) {
 607     return true;
 608   }
 609   // Compare primary supers
 610   int super_depth = klass->super_depth();
 611   int idx;
 612   for (idx = 0; idx < super_depth; idx++) {
 613     if (klass->primary_super_of_depth(idx)->name() == ty_sym) {
 614       return true;
 615     }
 616   }
 617   // Compare secondary supers
 618   Array<Klass*>* sec_supers = klass->secondary_supers();
 619   for (idx = 0; idx < sec_supers->length(); idx++) {
 620     if (((Klass*) sec_supers->at(idx))->name() == ty_sym) {
 621       return true;
 622     }
 623   }
 624   return false;
 625 }
 626 
 627 // Checks error conditions:
 628 //   JVMTI_ERROR_INVALID_SLOT
 629 //   JVMTI_ERROR_TYPE_MISMATCH
 630 // Returns: 'true' - everything is Ok, 'false' - error code
 631 
 632 bool VM_GetOrSetLocal::check_slot_type(javaVFrame* jvf) {
 633   Method* method_oop = jvf->method();
 634   if (!method_oop->has_localvariable_table()) {
 635     // Just to check index boundaries
 636     jint extra_slot = (_type == T_LONG || _type == T_DOUBLE) ? 1 : 0;
 637     if (_index < 0 || _index + extra_slot >= method_oop->max_locals()) {
 638       _result = JVMTI_ERROR_INVALID_SLOT;
 639       return false;
 640     }
 641     return true;
 642   }
 643 
 644   jint num_entries = method_oop->localvariable_table_length();
 645   if (num_entries == 0) {
 646     _result = JVMTI_ERROR_INVALID_SLOT;
 647     return false;       // There are no slots
 648   }
 649   int signature_idx = -1;
 650   int vf_bci = jvf->bci();
 651   LocalVariableTableElement* table = method_oop->localvariable_table_start();
 652   for (int i = 0; i < num_entries; i++) {
 653     int start_bci = table[i].start_bci;
 654     int end_bci = start_bci + table[i].length;
 655 
 656     // Here we assume that locations of LVT entries
 657     // with the same slot number cannot be overlapped
 658     if (_index == (jint) table[i].slot && start_bci <= vf_bci && vf_bci <= end_bci) {
 659       signature_idx = (int) table[i].descriptor_cp_index;
 660       break;
 661     }
 662   }
 663   if (signature_idx == -1) {
 664     _result = JVMTI_ERROR_INVALID_SLOT;
 665     return false;       // Incorrect slot index
 666   }
 667   Symbol*   sign_sym  = method_oop->constants()->symbol_at(signature_idx);
 668   const char* signature = (const char *) sign_sym->as_utf8();
 669   BasicType slot_type = char2type(signature[0]);
 670 
 671   switch (slot_type) {
 672   case T_BYTE:
 673   case T_SHORT:
 674   case T_CHAR:
 675   case T_BOOLEAN:
 676     slot_type = T_INT;
 677     break;
 678   case T_ARRAY:
 679     slot_type = T_OBJECT;
 680     break;
 681   };
 682   if (_type != slot_type) {
 683     _result = JVMTI_ERROR_TYPE_MISMATCH;
 684     return false;
 685   }
 686 
 687   jobject jobj = _value.l;
 688   if (_set && slot_type == T_OBJECT && jobj != NULL) { // NULL reference is allowed
 689     // Check that the jobject class matches the return type signature.
 690     JavaThread* cur_thread = JavaThread::current();
 691     HandleMark hm(cur_thread);
 692 
 693     Handle obj = Handle(cur_thread, JNIHandles::resolve_external_guard(jobj));
 694     NULL_CHECK(obj, (_result = JVMTI_ERROR_INVALID_OBJECT, false));
 695     KlassHandle ob_kh = KlassHandle(cur_thread, obj->klass());
 696     NULL_CHECK(ob_kh, (_result = JVMTI_ERROR_INVALID_OBJECT, false));
 697 
 698     if (!is_assignable(signature, ob_kh(), cur_thread)) {
 699       _result = JVMTI_ERROR_TYPE_MISMATCH;
 700       return false;
 701     }
 702   }
 703   return true;
 704 }
 705 
 706 static bool can_be_deoptimized(vframe* vf) {
 707   return (vf->is_compiled_frame() && vf->fr().can_be_deoptimized());
 708 }
 709 
 710 bool VM_GetOrSetLocal::doit_prologue() {
 711   _jvf = get_java_vframe();
 712   NULL_CHECK(_jvf, false);
 713 
 714   if (_jvf->method()->is_native()) {
 715     if (getting_receiver() && !_jvf->method()->is_static()) {
 716       return true;
 717     } else {
 718       _result = JVMTI_ERROR_OPAQUE_FRAME;
 719       return false;
 720     }
 721   }
 722 
 723   if (!check_slot_type(_jvf)) {
 724     return false;
 725   }
 726   return true;
 727 }
 728 
 729 void VM_GetOrSetLocal::doit() {
 730   if (_set) {
 731     // Force deoptimization of frame if compiled because it's
 732     // possible the compiler emitted some locals as constant values,
 733     // meaning they are not mutable.
 734     if (can_be_deoptimized(_jvf)) {
 735 
 736       // Schedule deoptimization so that eventually the local
 737       // update will be written to an interpreter frame.
 738       Deoptimization::deoptimize_frame(_jvf->thread(), _jvf->fr().id());
 739 
 740       // Now store a new value for the local which will be applied
 741       // once deoptimization occurs. Note however that while this
 742       // write is deferred until deoptimization actually happens
 743       // can vframe created after this point will have its locals
 744       // reflecting this update so as far as anyone can see the
 745       // write has already taken place.
 746 
 747       // If we are updating an oop then get the oop from the handle
 748       // since the handle will be long gone by the time the deopt
 749       // happens. The oop stored in the deferred local will be
 750       // gc'd on its own.
 751       if (_type == T_OBJECT) {
 752         _value.l = (jobject) (JNIHandles::resolve_external_guard(_value.l));
 753       }
 754       // Re-read the vframe so we can see that it is deoptimized
 755       // [ Only need because of assert in update_local() ]
 756       _jvf = get_java_vframe();
 757       ((compiledVFrame*)_jvf)->update_local(_type, _index, _value);
 758       return;
 759     }
 760     StackValueCollection *locals = _jvf->locals();
 761     HandleMark hm;
 762 
 763     switch (_type) {
 764       case T_INT:    locals->set_int_at   (_index, _value.i); break;
 765       case T_LONG:   locals->set_long_at  (_index, _value.j); break;
 766       case T_FLOAT:  locals->set_float_at (_index, _value.f); break;
 767       case T_DOUBLE: locals->set_double_at(_index, _value.d); break;
 768       case T_OBJECT: {
 769         Handle ob_h(JNIHandles::resolve_external_guard(_value.l));
 770         locals->set_obj_at (_index, ob_h);
 771         break;
 772       }
 773       default: ShouldNotReachHere();
 774     }
 775     _jvf->set_locals(locals);
 776   } else {
 777     if (_jvf->method()->is_native() && _jvf->is_compiled_frame()) {
 778       assert(getting_receiver(), "Can only get here when getting receiver");
 779       oop receiver = _jvf->fr().get_native_receiver();
 780       _value.l = JNIHandles::make_local(_calling_thread, receiver);
 781     } else {
 782       StackValueCollection *locals = _jvf->locals();
 783 
 784       if (locals->at(_index)->type() == T_CONFLICT) {
 785         memset(&_value, 0, sizeof(_value));
 786         _value.l = NULL;
 787         return;
 788       }
 789 
 790       switch (_type) {
 791         case T_INT:    _value.i = locals->int_at   (_index);   break;
 792         case T_LONG:   _value.j = locals->long_at  (_index);   break;
 793         case T_FLOAT:  _value.f = locals->float_at (_index);   break;
 794         case T_DOUBLE: _value.d = locals->double_at(_index);   break;
 795         case T_OBJECT: {
 796           // Wrap the oop to be returned in a local JNI handle since
 797           // oops_do() no longer applies after doit() is finished.
 798           oop obj = locals->obj_at(_index)();
 799           _value.l = JNIHandles::make_local(_calling_thread, obj);
 800           break;
 801         }
 802         default: ShouldNotReachHere();
 803       }
 804     }
 805   }
 806 }
 807 
 808 
 809 bool VM_GetOrSetLocal::allow_nested_vm_operations() const {
 810   return true; // May need to deoptimize
 811 }
 812 
 813 
 814 VM_GetReceiver::VM_GetReceiver(
 815     JavaThread* thread, JavaThread* caller_thread, jint depth)
 816     : VM_GetOrSetLocal(thread, caller_thread, depth, 0) {}
 817 
 818 /////////////////////////////////////////////////////////////////////////////////////////
 819 
 820 //
 821 // class JvmtiSuspendControl - see comments in jvmtiImpl.hpp
 822 //
 823 
 824 bool JvmtiSuspendControl::suspend(JavaThread *java_thread) {
 825   // external suspend should have caught suspending a thread twice
 826 
 827   // Immediate suspension required for JPDA back-end so JVMTI agent threads do
 828   // not deadlock due to later suspension on transitions while holding
 829   // raw monitors.  Passing true causes the immediate suspension.
 830   // java_suspend() will catch threads in the process of exiting
 831   // and will ignore them.
 832   java_thread->java_suspend();
 833 
 834   // It would be nice to have the following assertion in all the time,
 835   // but it is possible for a racing resume request to have resumed
 836   // this thread right after we suspended it. Temporarily enable this
 837   // assertion if you are chasing a different kind of bug.
 838   //
 839   // assert(java_lang_Thread::thread(java_thread->threadObj()) == NULL ||
 840   //   java_thread->is_being_ext_suspended(), "thread is not suspended");
 841 
 842   if (java_lang_Thread::thread(java_thread->threadObj()) == NULL) {
 843     // check again because we can get delayed in java_suspend():
 844     // the thread is in process of exiting.
 845     return false;
 846   }
 847 
 848   return true;
 849 }
 850 
 851 bool JvmtiSuspendControl::resume(JavaThread *java_thread) {
 852   // external suspend should have caught resuming a thread twice
 853   assert(java_thread->is_being_ext_suspended(), "thread should be suspended");
 854 
 855   // resume thread
 856   {
 857     // must always grab Threads_lock, see JVM_SuspendThread
 858     MutexLocker ml(Threads_lock);
 859     java_thread->java_resume();
 860   }
 861 
 862   return true;
 863 }
 864 
 865 
 866 void JvmtiSuspendControl::print() {
 867 #ifndef PRODUCT
 868   MutexLocker mu(Threads_lock);
 869   ResourceMark rm;
 870 
 871   tty->print("Suspended Threads: [");
 872   for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
 873 #ifdef JVMTI_TRACE
 874     const char *name   = JvmtiTrace::safe_get_thread_name(thread);
 875 #else
 876     const char *name   = "";
 877 #endif /*JVMTI_TRACE */
 878     tty->print("%s(%c ", name, thread->is_being_ext_suspended() ? 'S' : '_');
 879     if (!thread->has_last_Java_frame()) {
 880       tty->print("no stack");
 881     }
 882     tty->print(") ");
 883   }
 884   tty->print_cr("]");
 885 #endif
 886 }
 887 
 888 JvmtiDeferredEvent JvmtiDeferredEvent::compiled_method_load_event(
 889     nmethod* nm) {
 890   JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_COMPILED_METHOD_LOAD);
 891   event._event_data.compiled_method_load = nm;
 892   // Keep the nmethod alive until the ServiceThread can process
 893   // this deferred event.
 894   nmethodLocker::lock_nmethod(nm);
 895   return event;
 896 }
 897 
 898 JvmtiDeferredEvent JvmtiDeferredEvent::compiled_method_unload_event(
 899     nmethod* nm, jmethodID id, const void* code) {
 900   JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_COMPILED_METHOD_UNLOAD);
 901   event._event_data.compiled_method_unload.nm = nm;
 902   event._event_data.compiled_method_unload.method_id = id;
 903   event._event_data.compiled_method_unload.code_begin = code;
 904   // Keep the nmethod alive until the ServiceThread can process
 905   // this deferred event. This will keep the memory for the
 906   // generated code from being reused too early. We pass
 907   // zombie_ok == true here so that our nmethod that was just
 908   // made into a zombie can be locked.
 909   nmethodLocker::lock_nmethod(nm, true /* zombie_ok */);
 910   return event;
 911 }
 912 
 913 JvmtiDeferredEvent JvmtiDeferredEvent::dynamic_code_generated_event(
 914       const char* name, const void* code_begin, const void* code_end) {
 915   JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_DYNAMIC_CODE_GENERATED);
 916   // Need to make a copy of the name since we don't know how long
 917   // the event poster will keep it around after we enqueue the
 918   // deferred event and return. strdup() failure is handled in
 919   // the post() routine below.
 920   event._event_data.dynamic_code_generated.name = os::strdup(name);
 921   event._event_data.dynamic_code_generated.code_begin = code_begin;
 922   event._event_data.dynamic_code_generated.code_end = code_end;
 923   return event;
 924 }
 925 
 926 void JvmtiDeferredEvent::post() {
 927   assert(ServiceThread::is_service_thread(Thread::current()),
 928          "Service thread must post enqueued events");
 929   switch(_type) {
 930     case TYPE_COMPILED_METHOD_LOAD: {
 931       nmethod* nm = _event_data.compiled_method_load;
 932       JvmtiExport::post_compiled_method_load(nm);
 933       // done with the deferred event so unlock the nmethod
 934       nmethodLocker::unlock_nmethod(nm);
 935       break;
 936     }
 937     case TYPE_COMPILED_METHOD_UNLOAD: {
 938       nmethod* nm = _event_data.compiled_method_unload.nm;
 939       JvmtiExport::post_compiled_method_unload(
 940         _event_data.compiled_method_unload.method_id,
 941         _event_data.compiled_method_unload.code_begin);
 942       // done with the deferred event so unlock the nmethod
 943       nmethodLocker::unlock_nmethod(nm);
 944       break;
 945     }
 946     case TYPE_DYNAMIC_CODE_GENERATED: {
 947       JvmtiExport::post_dynamic_code_generated_internal(
 948         // if strdup failed give the event a default name
 949         (_event_data.dynamic_code_generated.name == NULL)
 950           ? "unknown_code" : _event_data.dynamic_code_generated.name,
 951         _event_data.dynamic_code_generated.code_begin,
 952         _event_data.dynamic_code_generated.code_end);
 953       if (_event_data.dynamic_code_generated.name != NULL) {
 954         // release our copy
 955         os::free((void *)_event_data.dynamic_code_generated.name);
 956       }
 957       break;
 958     }
 959     default:
 960       ShouldNotReachHere();
 961   }
 962 }
 963 
 964 JvmtiDeferredEventQueue::QueueNode* JvmtiDeferredEventQueue::_queue_tail = NULL;
 965 JvmtiDeferredEventQueue::QueueNode* JvmtiDeferredEventQueue::_queue_head = NULL;
 966 
 967 volatile JvmtiDeferredEventQueue::QueueNode*
 968     JvmtiDeferredEventQueue::_pending_list = NULL;
 969 
 970 bool JvmtiDeferredEventQueue::has_events() {
 971   assert(Service_lock->owned_by_self(), "Must own Service_lock");
 972   return _queue_head != NULL || _pending_list != NULL;
 973 }
 974 
 975 void JvmtiDeferredEventQueue::enqueue(const JvmtiDeferredEvent& event) {
 976   assert(Service_lock->owned_by_self(), "Must own Service_lock");
 977 
 978   process_pending_events();
 979 
 980   // Events get added to the end of the queue (and are pulled off the front).
 981   QueueNode* node = new QueueNode(event);
 982   if (_queue_tail == NULL) {
 983     _queue_tail = _queue_head = node;
 984   } else {
 985     assert(_queue_tail->next() == NULL, "Must be the last element in the list");
 986     _queue_tail->set_next(node);
 987     _queue_tail = node;
 988   }
 989 
 990   Service_lock->notify_all();
 991   assert((_queue_head == NULL) == (_queue_tail == NULL),
 992          "Inconsistent queue markers");
 993 }
 994 
 995 JvmtiDeferredEvent JvmtiDeferredEventQueue::dequeue() {
 996   assert(Service_lock->owned_by_self(), "Must own Service_lock");
 997 
 998   process_pending_events();
 999 
1000   assert(_queue_head != NULL, "Nothing to dequeue");
1001 
1002   if (_queue_head == NULL) {
1003     // Just in case this happens in product; it shouldn't but let's not crash
1004     return JvmtiDeferredEvent();
1005   }
1006 
1007   QueueNode* node = _queue_head;
1008   _queue_head = _queue_head->next();
1009   if (_queue_head == NULL) {
1010     _queue_tail = NULL;
1011   }
1012 
1013   assert((_queue_head == NULL) == (_queue_tail == NULL),
1014          "Inconsistent queue markers");
1015 
1016   JvmtiDeferredEvent event = node->event();
1017   delete node;
1018   return event;
1019 }
1020 
1021 void JvmtiDeferredEventQueue::add_pending_event(
1022     const JvmtiDeferredEvent& event) {
1023 
1024   QueueNode* node = new QueueNode(event);
1025 
1026   bool success = false;
1027   QueueNode* prev_value = (QueueNode*)_pending_list;
1028   do {
1029     node->set_next(prev_value);
1030     prev_value = (QueueNode*)Atomic::cmpxchg_ptr(
1031         (void*)node, (volatile void*)&_pending_list, (void*)node->next());
1032   } while (prev_value != node->next());
1033 }
1034 
1035 // This method transfers any events that were added by someone NOT holding
1036 // the lock into the mainline queue.
1037 void JvmtiDeferredEventQueue::process_pending_events() {
1038   assert(Service_lock->owned_by_self(), "Must own Service_lock");
1039 
1040   if (_pending_list != NULL) {
1041     QueueNode* head =
1042         (QueueNode*)Atomic::xchg_ptr(NULL, (volatile void*)&_pending_list);
1043 
1044     assert((_queue_head == NULL) == (_queue_tail == NULL),
1045            "Inconsistent queue markers");
1046 
1047     if (head != NULL) {
1048       // Since we've treated the pending list as a stack (with newer
1049       // events at the beginning), we need to join the bottom of the stack
1050       // with the 'tail' of the queue in order to get the events in the
1051       // right order.  We do this by reversing the pending list and appending
1052       // it to the queue.
1053 
1054       QueueNode* new_tail = head;
1055       QueueNode* new_head = NULL;
1056 
1057       // This reverses the list
1058       QueueNode* prev = new_tail;
1059       QueueNode* node = new_tail->next();
1060       new_tail->set_next(NULL);
1061       while (node != NULL) {
1062         QueueNode* next = node->next();
1063         node->set_next(prev);
1064         prev = node;
1065         node = next;
1066       }
1067       new_head = prev;
1068 
1069       // Now append the new list to the queue
1070       if (_queue_tail != NULL) {
1071         _queue_tail->set_next(new_head);
1072       } else { // _queue_head == NULL
1073         _queue_head = new_head;
1074       }
1075       _queue_tail = new_tail;
1076     }
1077   }
1078 }