1 /*
   2  * Copyright (c) 2003, 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 #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/serviceThread.hpp"
  42 #include "runtime/signature.hpp"
  43 #include "runtime/vframe.hpp"
  44 #include "runtime/vframe_hp.hpp"
  45 #include "runtime/vm_operations.hpp"
  46 #include "utilities/exceptions.hpp"
  47 #ifdef TARGET_OS_FAMILY_linux
  48 # include "thread_linux.inline.hpp"
  49 #endif
  50 #ifdef TARGET_OS_FAMILY_solaris
  51 # include "thread_solaris.inline.hpp"
  52 #endif
  53 #ifdef TARGET_OS_FAMILY_windows
  54 # include "thread_windows.inline.hpp"
  55 #endif
  56 
  57 //
  58 // class JvmtiAgentThread
  59 //
  60 // JavaThread used to wrap a thread started by an agent
  61 // using the JVMTI method RunAgentThread.
  62 //
  63 
  64 JvmtiAgentThread::JvmtiAgentThread(JvmtiEnv* env, jvmtiStartFunction start_fn, const void *start_arg)
  65     : JavaThread(start_function_wrapper) {
  66     _env = env;
  67     _start_fn = start_fn;
  68     _start_arg = start_arg;
  69 }
  70 
  71 void
  72 JvmtiAgentThread::start_function_wrapper(JavaThread *thread, TRAPS) {
  73     // It is expected that any Agent threads will be created as
  74     // Java Threads.  If this is the case, notification of the creation
  75     // of the thread is given in JavaThread::thread_main().
  76     assert(thread->is_Java_thread(), "debugger thread should be a Java Thread");
  77     assert(thread == JavaThread::current(), "sanity check");
  78 
  79     JvmtiAgentThread *dthread = (JvmtiAgentThread *)thread;
  80     dthread->call_start_function();
  81 }
  82 
  83 void
  84 JvmtiAgentThread::call_start_function() {
  85     ThreadToNativeFromVM transition(this);
  86     _start_fn(_env->jvmti_external(), jni_environment(), (void*)_start_arg);
  87 }
  88 
  89 
  90 //
  91 // class GrowableCache - private methods
  92 //
  93 
  94 void GrowableCache::recache() {
  95   int len = _elements->length();
  96 
  97   FREE_C_HEAP_ARRAY(address, _cache);
  98   _cache = NEW_C_HEAP_ARRAY(address,len+1);
  99 
 100   for (int i=0; i<len; i++) {
 101     _cache[i] = _elements->at(i)->getCacheValue();
 102     //
 103     // The cache entry has gone bad. Without a valid frame pointer
 104     // value, the entry is useless so we simply delete it in product
 105     // mode. The call to remove() will rebuild the cache again
 106     // without the bad entry.
 107     //
 108     if (_cache[i] == NULL) {
 109       assert(false, "cannot recache NULL elements");
 110       remove(i);
 111       return;
 112     }
 113   }
 114   _cache[len] = NULL;
 115 
 116   _listener_fun(_this_obj,_cache);
 117 }
 118 
 119 bool GrowableCache::equals(void* v, GrowableElement *e2) {
 120   GrowableElement *e1 = (GrowableElement *) v;
 121   assert(e1 != NULL, "e1 != NULL");
 122   assert(e2 != NULL, "e2 != NULL");
 123 
 124   return e1->equals(e2);
 125 }
 126 
 127 //
 128 // class GrowableCache - public methods
 129 //
 130 
 131 GrowableCache::GrowableCache() {
 132   _this_obj       = NULL;
 133   _listener_fun   = NULL;
 134   _elements       = NULL;
 135   _cache          = NULL;
 136 }
 137 
 138 GrowableCache::~GrowableCache() {
 139   clear();
 140   delete _elements;
 141   FREE_C_HEAP_ARRAY(address, _cache);
 142 }
 143 
 144 void GrowableCache::initialize(void *this_obj, void listener_fun(void *, address*) ) {
 145   _this_obj       = this_obj;
 146   _listener_fun   = listener_fun;
 147   _elements       = new (ResourceObj::C_HEAP) GrowableArray<GrowableElement*>(5,true);
 148   recache();
 149 }
 150 
 151 // number of elements in the collection
 152 int GrowableCache::length() {
 153   return _elements->length();
 154 }
 155 
 156 // get the value of the index element in the collection
 157 GrowableElement* GrowableCache::at(int index) {
 158   GrowableElement *e = (GrowableElement *) _elements->at(index);
 159   assert(e != NULL, "e != NULL");
 160   return e;
 161 }
 162 
 163 int GrowableCache::find(GrowableElement* e) {
 164   return _elements->find(e, GrowableCache::equals);
 165 }
 166 
 167 // append a copy of the element to the end of the collection
 168 void GrowableCache::append(GrowableElement* e) {
 169   GrowableElement *new_e = e->clone();
 170   _elements->append(new_e);
 171   recache();
 172 }
 173 
 174 // insert a copy of the element using lessthan()
 175 void GrowableCache::insert(GrowableElement* e) {
 176   GrowableElement *new_e = e->clone();
 177   _elements->append(new_e);
 178 
 179   int n = length()-2;
 180   for (int i=n; i>=0; i--) {
 181     GrowableElement *e1 = _elements->at(i);
 182     GrowableElement *e2 = _elements->at(i+1);
 183     if (e2->lessThan(e1)) {
 184       _elements->at_put(i+1, e1);
 185       _elements->at_put(i,   e2);
 186     }
 187   }
 188 
 189   recache();
 190 }
 191 
 192 // remove the element at index
 193 void GrowableCache::remove (int index) {
 194   GrowableElement *e = _elements->at(index);
 195   assert(e != NULL, "e != NULL");
 196   _elements->remove(e);
 197   delete e;
 198   recache();
 199 }
 200 
 201 // clear out all elements, release all heap space and
 202 // let our listener know that things have changed.
 203 void GrowableCache::clear() {
 204   int len = _elements->length();
 205   for (int i=0; i<len; i++) {
 206     delete _elements->at(i);
 207   }
 208   _elements->clear();
 209   recache();
 210 }
 211 
 212 void GrowableCache::oops_do(OopClosure* f) {
 213   int len = _elements->length();
 214   for (int i=0; i<len; i++) {
 215     GrowableElement *e = _elements->at(i);
 216     e->oops_do(f);
 217   }
 218 }
 219 
 220 void GrowableCache::gc_epilogue() {
 221   int len = _elements->length();
 222   for (int i=0; i<len; i++) {
 223     _cache[i] = _elements->at(i)->getCacheValue();
 224   }
 225 }
 226 
 227 //
 228 // class JvmtiBreakpoint
 229 //
 230 
 231 JvmtiBreakpoint::JvmtiBreakpoint() {
 232   _method = NULL;
 233   _bci    = 0;
 234 #ifdef CHECK_UNHANDLED_OOPS
 235   // This one is always allocated with new, but check it just in case.
 236   Thread *thread = Thread::current();
 237   if (thread->is_in_stack((address)&_method)) {
 238     thread->allow_unhandled_oop((oop*)&_method);
 239   }
 240 #endif // CHECK_UNHANDLED_OOPS
 241 }
 242 
 243 JvmtiBreakpoint::JvmtiBreakpoint(methodOop m_method, jlocation location) {
 244   _method        = m_method;
 245   assert(_method != NULL, "_method != NULL");
 246   _bci           = (int) location;
 247 #ifdef CHECK_UNHANDLED_OOPS
 248   // Could be allocated with new and wouldn't be on the unhandled oop list.
 249   Thread *thread = Thread::current();
 250   if (thread->is_in_stack((address)&_method)) {
 251     thread->allow_unhandled_oop(&_method);
 252   }
 253 #endif // CHECK_UNHANDLED_OOPS
 254 
 255   assert(_bci >= 0, "_bci >= 0");
 256 }
 257 
 258 void JvmtiBreakpoint::copy(JvmtiBreakpoint& bp) {
 259   _method   = bp._method;
 260   _bci      = bp._bci;
 261 }
 262 
 263 bool JvmtiBreakpoint::lessThan(JvmtiBreakpoint& bp) {
 264   Unimplemented();
 265   return false;
 266 }
 267 
 268 bool JvmtiBreakpoint::equals(JvmtiBreakpoint& bp) {
 269   return _method   == bp._method
 270     &&   _bci      == bp._bci;
 271 }
 272 
 273 bool JvmtiBreakpoint::is_valid() {
 274   return _method != NULL &&
 275          _bci >= 0;
 276 }
 277 
 278 address JvmtiBreakpoint::getBcp() {
 279   return _method->bcp_from(_bci);
 280 }
 281 
 282 void JvmtiBreakpoint::each_method_version_do(method_action meth_act) {
 283   ((methodOopDesc*)_method->*meth_act)(_bci);
 284 
 285   // add/remove breakpoint to/from versions of the method that
 286   // are EMCP. Directly or transitively obsolete methods are
 287   // not saved in the PreviousVersionInfo.
 288   Thread *thread = Thread::current();
 289   instanceKlassHandle ikh = instanceKlassHandle(thread, _method->method_holder());
 290   Symbol* m_name = _method->name();
 291   Symbol* m_signature = _method->signature();
 292 
 293   {
 294     ResourceMark rm(thread);
 295     // PreviousVersionInfo objects returned via PreviousVersionWalker
 296     // contain a GrowableArray of handles. We have to clean up the
 297     // GrowableArray _after_ the PreviousVersionWalker destructor
 298     // has destroyed the handles.
 299     {
 300       // search previous versions if they exist
 301       PreviousVersionWalker pvw((instanceKlass *)ikh()->klass_part());
 302       for (PreviousVersionInfo * pv_info = pvw.next_previous_version();
 303            pv_info != NULL; pv_info = pvw.next_previous_version()) {
 304         GrowableArray<methodHandle>* methods =
 305           pv_info->prev_EMCP_method_handles();
 306 
 307         if (methods == NULL) {
 308           // We have run into a PreviousVersion generation where
 309           // all methods were made obsolete during that generation's
 310           // RedefineClasses() operation. At the time of that
 311           // operation, all EMCP methods were flushed so we don't
 312           // have to go back any further.
 313           //
 314           // A NULL methods array is different than an empty methods
 315           // array. We cannot infer any optimizations about older
 316           // generations from an empty methods array for the current
 317           // generation.
 318           break;
 319         }
 320 
 321         for (int i = methods->length() - 1; i >= 0; i--) {
 322           methodHandle method = methods->at(i);
 323           if (method->name() == m_name && method->signature() == m_signature) {
 324             RC_TRACE(0x00000800, ("%sing breakpoint in %s(%s)",
 325               meth_act == &methodOopDesc::set_breakpoint ? "sett" : "clear",
 326               method->name()->as_C_string(),
 327               method->signature()->as_C_string()));
 328             assert(!method->is_obsolete(), "only EMCP methods here");
 329 
 330             ((methodOopDesc*)method()->*meth_act)(_bci);
 331             break;
 332           }
 333         }
 334       }
 335     } // pvw is cleaned up
 336   } // rm is cleaned up
 337 }
 338 
 339 void JvmtiBreakpoint::set() {
 340   each_method_version_do(&methodOopDesc::set_breakpoint);
 341 }
 342 
 343 void JvmtiBreakpoint::clear() {
 344   each_method_version_do(&methodOopDesc::clear_breakpoint);
 345 }
 346 
 347 void JvmtiBreakpoint::print() {
 348 #ifndef PRODUCT
 349   const char *class_name  = (_method == NULL) ? "NULL" : _method->klass_name()->as_C_string();
 350   const char *method_name = (_method == NULL) ? "NULL" : _method->name()->as_C_string();
 351 
 352   tty->print("Breakpoint(%s,%s,%d,%p)",class_name, method_name, _bci, getBcp());
 353 #endif
 354 }
 355 
 356 
 357 //
 358 // class VM_ChangeBreakpoints
 359 //
 360 // Modify the Breakpoints data structure at a safepoint
 361 //
 362 
 363 void VM_ChangeBreakpoints::doit() {
 364   switch (_operation) {
 365   case SET_BREAKPOINT:
 366     _breakpoints->set_at_safepoint(*_bp);
 367     break;
 368   case CLEAR_BREAKPOINT:
 369     _breakpoints->clear_at_safepoint(*_bp);
 370     break;
 371   case CLEAR_ALL_BREAKPOINT:
 372     _breakpoints->clearall_at_safepoint();
 373     break;
 374   default:
 375     assert(false, "Unknown operation");
 376   }
 377 }
 378 
 379 void VM_ChangeBreakpoints::oops_do(OopClosure* f) {
 380   // This operation keeps breakpoints alive
 381   if (_breakpoints != NULL) {
 382     _breakpoints->oops_do(f);
 383   }
 384   if (_bp != NULL) {
 385     _bp->oops_do(f);
 386   }
 387 }
 388 
 389 //
 390 // class JvmtiBreakpoints
 391 //
 392 // a JVMTI internal collection of JvmtiBreakpoint
 393 //
 394 
 395 JvmtiBreakpoints::JvmtiBreakpoints(void listener_fun(void *,address *)) {
 396   _bps.initialize(this,listener_fun);
 397 }
 398 
 399 JvmtiBreakpoints:: ~JvmtiBreakpoints() {}
 400 
 401 void  JvmtiBreakpoints::oops_do(OopClosure* f) {
 402   _bps.oops_do(f);
 403 }
 404 
 405 void JvmtiBreakpoints::gc_epilogue() {
 406   _bps.gc_epilogue();
 407 }
 408 
 409 void  JvmtiBreakpoints::print() {
 410 #ifndef PRODUCT
 411   ResourceMark rm;
 412 
 413   int n = _bps.length();
 414   for (int i=0; i<n; i++) {
 415     JvmtiBreakpoint& bp = _bps.at(i);
 416     tty->print("%d: ", i);
 417     bp.print();
 418     tty->print_cr("");
 419   }
 420 #endif
 421 }
 422 
 423 
 424 void JvmtiBreakpoints::set_at_safepoint(JvmtiBreakpoint& bp) {
 425   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 426 
 427   int i = _bps.find(bp);
 428   if (i == -1) {
 429     _bps.append(bp);
 430     bp.set();
 431   }
 432 }
 433 
 434 void JvmtiBreakpoints::clear_at_safepoint(JvmtiBreakpoint& bp) {
 435   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 436 
 437   int i = _bps.find(bp);
 438   if (i != -1) {
 439     _bps.remove(i);
 440     bp.clear();
 441   }
 442 }
 443 
 444 void JvmtiBreakpoints::clearall_at_safepoint() {
 445   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 446 
 447   int len = _bps.length();
 448   for (int i=0; i<len; i++) {
 449     _bps.at(i).clear();
 450   }
 451   _bps.clear();
 452 }
 453 
 454 int JvmtiBreakpoints::length() { return _bps.length(); }
 455 
 456 int JvmtiBreakpoints::set(JvmtiBreakpoint& bp) {
 457   if ( _bps.find(bp) != -1) {
 458      return JVMTI_ERROR_DUPLICATE;
 459   }
 460   VM_ChangeBreakpoints set_breakpoint(this,VM_ChangeBreakpoints::SET_BREAKPOINT, &bp);
 461   VMThread::execute(&set_breakpoint);
 462   return JVMTI_ERROR_NONE;
 463 }
 464 
 465 int JvmtiBreakpoints::clear(JvmtiBreakpoint& bp) {
 466   if ( _bps.find(bp) == -1) {
 467      return JVMTI_ERROR_NOT_FOUND;
 468   }
 469 
 470   VM_ChangeBreakpoints clear_breakpoint(this,VM_ChangeBreakpoints::CLEAR_BREAKPOINT, &bp);
 471   VMThread::execute(&clear_breakpoint);
 472   return JVMTI_ERROR_NONE;
 473 }
 474 
 475 void JvmtiBreakpoints::clearall_in_class_at_safepoint(klassOop klass) {
 476   bool changed = true;
 477   // We are going to run thru the list of bkpts
 478   // and delete some.  This deletion probably alters
 479   // the list in some implementation defined way such
 480   // that when we delete entry i, the next entry might
 481   // no longer be at i+1.  To be safe, each time we delete
 482   // an entry, we'll just start again from the beginning.
 483   // We'll stop when we make a pass thru the whole list without
 484   // deleting anything.
 485   while (changed) {
 486     int len = _bps.length();
 487     changed = false;
 488     for (int i = 0; i < len; i++) {
 489       JvmtiBreakpoint& bp = _bps.at(i);
 490       if (bp.method()->method_holder() == klass) {
 491         bp.clear();
 492         _bps.remove(i);
 493         // This changed 'i' so we have to start over.
 494         changed = true;
 495         break;
 496       }
 497     }
 498   }
 499 }
 500 
 501 void JvmtiBreakpoints::clearall() {
 502   VM_ChangeBreakpoints clearall_breakpoint(this,VM_ChangeBreakpoints::CLEAR_ALL_BREAKPOINT);
 503   VMThread::execute(&clearall_breakpoint);
 504 }
 505 
 506 //
 507 // class JvmtiCurrentBreakpoints
 508 //
 509 
 510 JvmtiBreakpoints *JvmtiCurrentBreakpoints::_jvmti_breakpoints  = NULL;
 511 address *         JvmtiCurrentBreakpoints::_breakpoint_list    = NULL;
 512 
 513 
 514 JvmtiBreakpoints& JvmtiCurrentBreakpoints::get_jvmti_breakpoints() {
 515   if (_jvmti_breakpoints != NULL) return (*_jvmti_breakpoints);
 516   _jvmti_breakpoints = new JvmtiBreakpoints(listener_fun);
 517   assert(_jvmti_breakpoints != NULL, "_jvmti_breakpoints != NULL");
 518   return (*_jvmti_breakpoints);
 519 }
 520 
 521 void  JvmtiCurrentBreakpoints::listener_fun(void *this_obj, address *cache) {
 522   JvmtiBreakpoints *this_jvmti = (JvmtiBreakpoints *) this_obj;
 523   assert(this_jvmti != NULL, "this_jvmti != NULL");
 524 
 525   debug_only(int n = this_jvmti->length(););
 526   assert(cache[n] == NULL, "cache must be NULL terminated");
 527 
 528   set_breakpoint_list(cache);
 529 }
 530 
 531 
 532 void JvmtiCurrentBreakpoints::oops_do(OopClosure* f) {
 533   if (_jvmti_breakpoints != NULL) {
 534     _jvmti_breakpoints->oops_do(f);
 535   }
 536 }
 537 
 538 void JvmtiCurrentBreakpoints::gc_epilogue() {
 539   if (_jvmti_breakpoints != NULL) {
 540     _jvmti_breakpoints->gc_epilogue();
 541   }
 542 }
 543 
 544 ///////////////////////////////////////////////////////////////
 545 //
 546 // class VM_GetOrSetLocal
 547 //
 548 
 549 // Constructor for non-object getter
 550 VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, jint depth, int index, BasicType type)
 551   : _thread(thread)
 552   , _calling_thread(NULL)
 553   , _depth(depth)
 554   , _index(index)
 555   , _type(type)
 556   , _set(false)
 557   , _jvf(NULL)
 558   , _result(JVMTI_ERROR_NONE)
 559 {
 560 }
 561 
 562 // Constructor for object or non-object setter
 563 VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, jint depth, int index, BasicType type, jvalue value)
 564   : _thread(thread)
 565   , _calling_thread(NULL)
 566   , _depth(depth)
 567   , _index(index)
 568   , _type(type)
 569   , _value(value)
 570   , _set(true)
 571   , _jvf(NULL)
 572   , _result(JVMTI_ERROR_NONE)
 573 {
 574 }
 575 
 576 // Constructor for object getter
 577 VM_GetOrSetLocal::VM_GetOrSetLocal(JavaThread* thread, JavaThread* calling_thread, jint depth, int index)
 578   : _thread(thread)
 579   , _calling_thread(calling_thread)
 580   , _depth(depth)
 581   , _index(index)
 582   , _type(T_OBJECT)
 583   , _set(false)
 584   , _jvf(NULL)
 585   , _result(JVMTI_ERROR_NONE)
 586 {
 587 }
 588 
 589 vframe *VM_GetOrSetLocal::get_vframe() {
 590   if (!_thread->has_last_Java_frame()) {
 591     return NULL;
 592   }
 593   RegisterMap reg_map(_thread);
 594   vframe *vf = _thread->last_java_vframe(&reg_map);
 595   int d = 0;
 596   while ((vf != NULL) && (d < _depth)) {
 597     vf = vf->java_sender();
 598     d++;
 599   }
 600   return vf;
 601 }
 602 
 603 javaVFrame *VM_GetOrSetLocal::get_java_vframe() {
 604   vframe* vf = get_vframe();
 605   if (vf == NULL) {
 606     _result = JVMTI_ERROR_NO_MORE_FRAMES;
 607     return NULL;
 608   }
 609   javaVFrame *jvf = (javaVFrame*)vf;
 610 
 611   if (!vf->is_java_frame()) {
 612     _result = JVMTI_ERROR_OPAQUE_FRAME;
 613     return NULL;
 614   }
 615   return jvf;
 616 }
 617 
 618 // Check that the klass is assignable to a type with the given signature.
 619 // Another solution could be to use the function Klass::is_subtype_of(type).
 620 // But the type class can be forced to load/initialize eagerly in such a case.
 621 // This may cause unexpected consequences like CFLH or class-init JVMTI events.
 622 // It is better to avoid such a behavior.
 623 bool VM_GetOrSetLocal::is_assignable(const char* ty_sign, Klass* klass, Thread* thread) {
 624   assert(ty_sign != NULL, "type signature must not be NULL");
 625   assert(thread != NULL, "thread must not be NULL");
 626   assert(klass != NULL, "klass must not be NULL");
 627 
 628   int len = (int) strlen(ty_sign);
 629   if (ty_sign[0] == 'L' && ty_sign[len-1] == ';') { // Need pure class/interface name
 630     ty_sign++;
 631     len -= 2;
 632   }
 633   TempNewSymbol ty_sym = SymbolTable::new_symbol(ty_sign, len, thread);
 634   if (klass->name() == ty_sym) {
 635     return true;
 636   }
 637   // Compare primary supers
 638   int super_depth = klass->super_depth();
 639   int idx;
 640   for (idx = 0; idx < super_depth; idx++) {
 641     if (Klass::cast(klass->primary_super_of_depth(idx))->name() == ty_sym) {
 642       return true;
 643     }
 644   }
 645   // Compare secondary supers
 646   objArrayOop sec_supers = klass->secondary_supers();
 647   for (idx = 0; idx < sec_supers->length(); idx++) {
 648     if (Klass::cast((klassOop) sec_supers->obj_at(idx))->name() == ty_sym) {
 649       return true;
 650     }
 651   }
 652   return false;
 653 }
 654 
 655 // Checks error conditions:
 656 //   JVMTI_ERROR_INVALID_SLOT
 657 //   JVMTI_ERROR_TYPE_MISMATCH
 658 // Returns: 'true' - everything is Ok, 'false' - error code
 659 
 660 bool VM_GetOrSetLocal::check_slot_type(javaVFrame* jvf) {
 661   methodOop method_oop = jvf->method();
 662   if (!method_oop->has_localvariable_table()) {
 663     // Just to check index boundaries
 664     jint extra_slot = (_type == T_LONG || _type == T_DOUBLE) ? 1 : 0;
 665     if (_index < 0 || _index + extra_slot >= method_oop->max_locals()) {
 666       _result = JVMTI_ERROR_INVALID_SLOT;
 667       return false;
 668     }
 669     return true;
 670   }
 671 
 672   jint num_entries = method_oop->localvariable_table_length();
 673   if (num_entries == 0) {
 674     _result = JVMTI_ERROR_INVALID_SLOT;
 675     return false;       // There are no slots
 676   }
 677   int signature_idx = -1;
 678   int vf_bci = jvf->bci();
 679   LocalVariableTableElement* table = method_oop->localvariable_table_start();
 680   for (int i = 0; i < num_entries; i++) {
 681     int start_bci = table[i].start_bci;
 682     int end_bci = start_bci + table[i].length;
 683 
 684     // Here we assume that locations of LVT entries
 685     // with the same slot number cannot be overlapped
 686     if (_index == (jint) table[i].slot && start_bci <= vf_bci && vf_bci <= end_bci) {
 687       signature_idx = (int) table[i].descriptor_cp_index;
 688       break;
 689     }
 690   }
 691   if (signature_idx == -1) {
 692     _result = JVMTI_ERROR_INVALID_SLOT;
 693     return false;       // Incorrect slot index
 694   }
 695   Symbol*   sign_sym  = method_oop->constants()->symbol_at(signature_idx);
 696   const char* signature = (const char *) sign_sym->as_utf8();
 697   BasicType slot_type = char2type(signature[0]);
 698 
 699   switch (slot_type) {
 700   case T_BYTE:
 701   case T_SHORT:
 702   case T_CHAR:
 703   case T_BOOLEAN:
 704     slot_type = T_INT;
 705     break;
 706   case T_ARRAY:
 707     slot_type = T_OBJECT;
 708     break;
 709   };
 710   if (_type != slot_type) {
 711     _result = JVMTI_ERROR_TYPE_MISMATCH;
 712     return false;
 713   }
 714 
 715   jobject jobj = _value.l;
 716   if (_set && slot_type == T_OBJECT && jobj != NULL) { // NULL reference is allowed
 717     // Check that the jobject class matches the return type signature.
 718     JavaThread* cur_thread = JavaThread::current();
 719     HandleMark hm(cur_thread);
 720 
 721     Handle obj = Handle(cur_thread, JNIHandles::resolve_external_guard(jobj));
 722     NULL_CHECK(obj, (_result = JVMTI_ERROR_INVALID_OBJECT, false));
 723     KlassHandle ob_kh = KlassHandle(cur_thread, obj->klass());
 724     NULL_CHECK(ob_kh, (_result = JVMTI_ERROR_INVALID_OBJECT, false));
 725 
 726     if (!is_assignable(signature, Klass::cast(ob_kh()), cur_thread)) {
 727       _result = JVMTI_ERROR_TYPE_MISMATCH;
 728       return false;
 729     }
 730   }
 731   return true;
 732 }
 733 
 734 static bool can_be_deoptimized(vframe* vf) {
 735   return (vf->is_compiled_frame() && vf->fr().can_be_deoptimized());
 736 }
 737 
 738 bool VM_GetOrSetLocal::doit_prologue() {
 739   _jvf = get_java_vframe();
 740   NULL_CHECK(_jvf, false);
 741 
 742   if (_jvf->method()->is_native()) {
 743     if (getting_receiver() && !_jvf->method()->is_static()) {
 744       return true;
 745     } else {
 746       _result = JVMTI_ERROR_OPAQUE_FRAME;
 747       return false;
 748     }
 749   }
 750 
 751   if (!check_slot_type(_jvf)) {
 752     return false;
 753   }
 754   return true;
 755 }
 756 
 757 void VM_GetOrSetLocal::doit() {
 758   if (_set) {
 759     // Force deoptimization of frame if compiled because it's
 760     // possible the compiler emitted some locals as constant values,
 761     // meaning they are not mutable.
 762     if (can_be_deoptimized(_jvf)) {
 763 
 764       // Schedule deoptimization so that eventually the local
 765       // update will be written to an interpreter frame.
 766       Deoptimization::deoptimize_frame(_jvf->thread(), _jvf->fr().id());
 767 
 768       // Now store a new value for the local which will be applied
 769       // once deoptimization occurs. Note however that while this
 770       // write is deferred until deoptimization actually happens
 771       // can vframe created after this point will have its locals
 772       // reflecting this update so as far as anyone can see the
 773       // write has already taken place.
 774 
 775       // If we are updating an oop then get the oop from the handle
 776       // since the handle will be long gone by the time the deopt
 777       // happens. The oop stored in the deferred local will be
 778       // gc'd on its own.
 779       if (_type == T_OBJECT) {
 780         _value.l = (jobject) (JNIHandles::resolve_external_guard(_value.l));
 781       }
 782       // Re-read the vframe so we can see that it is deoptimized
 783       // [ Only need because of assert in update_local() ]
 784       _jvf = get_java_vframe();
 785       ((compiledVFrame*)_jvf)->update_local(_type, _index, _value);
 786       return;
 787     }
 788     StackValueCollection *locals = _jvf->locals();
 789     HandleMark hm;
 790 
 791     switch (_type) {
 792       case T_INT:    locals->set_int_at   (_index, _value.i); break;
 793       case T_LONG:   locals->set_long_at  (_index, _value.j); break;
 794       case T_FLOAT:  locals->set_float_at (_index, _value.f); break;
 795       case T_DOUBLE: locals->set_double_at(_index, _value.d); break;
 796       case T_OBJECT: {
 797         Handle ob_h(JNIHandles::resolve_external_guard(_value.l));
 798         locals->set_obj_at (_index, ob_h);
 799         break;
 800       }
 801       default: ShouldNotReachHere();
 802     }
 803     _jvf->set_locals(locals);
 804   } else {
 805     if (_jvf->method()->is_native() && _jvf->is_compiled_frame()) {
 806       assert(getting_receiver(), "Can only get here when getting receiver");
 807       oop receiver = _jvf->fr().get_native_receiver();
 808       _value.l = JNIHandles::make_local(_calling_thread, receiver);
 809     } else {
 810       StackValueCollection *locals = _jvf->locals();
 811 
 812       if (locals->at(_index)->type() == T_CONFLICT) {
 813         memset(&_value, 0, sizeof(_value));
 814         _value.l = NULL;
 815         return;
 816       }
 817 
 818       switch (_type) {
 819         case T_INT:    _value.i = locals->int_at   (_index);   break;
 820         case T_LONG:   _value.j = locals->long_at  (_index);   break;
 821         case T_FLOAT:  _value.f = locals->float_at (_index);   break;
 822         case T_DOUBLE: _value.d = locals->double_at(_index);   break;
 823         case T_OBJECT: {
 824           // Wrap the oop to be returned in a local JNI handle since
 825           // oops_do() no longer applies after doit() is finished.
 826           oop obj = locals->obj_at(_index)();
 827           _value.l = JNIHandles::make_local(_calling_thread, obj);
 828           break;
 829         }
 830         default: ShouldNotReachHere();
 831       }
 832     }
 833   }
 834 }
 835 
 836 
 837 bool VM_GetOrSetLocal::allow_nested_vm_operations() const {
 838   return true; // May need to deoptimize
 839 }
 840 
 841 
 842 VM_GetReceiver::VM_GetReceiver(
 843     JavaThread* thread, JavaThread* caller_thread, jint depth)
 844     : VM_GetOrSetLocal(thread, caller_thread, depth, 0) {}
 845 
 846 /////////////////////////////////////////////////////////////////////////////////////////
 847 
 848 //
 849 // class JvmtiSuspendControl - see comments in jvmtiImpl.hpp
 850 //
 851 
 852 bool JvmtiSuspendControl::suspend(JavaThread *java_thread) {
 853   // external suspend should have caught suspending a thread twice
 854 
 855   // Immediate suspension required for JPDA back-end so JVMTI agent threads do
 856   // not deadlock due to later suspension on transitions while holding
 857   // raw monitors.  Passing true causes the immediate suspension.
 858   // java_suspend() will catch threads in the process of exiting
 859   // and will ignore them.
 860   java_thread->java_suspend();
 861 
 862   // It would be nice to have the following assertion in all the time,
 863   // but it is possible for a racing resume request to have resumed
 864   // this thread right after we suspended it. Temporarily enable this
 865   // assertion if you are chasing a different kind of bug.
 866   //
 867   // assert(java_lang_Thread::thread(java_thread->threadObj()) == NULL ||
 868   //   java_thread->is_being_ext_suspended(), "thread is not suspended");
 869 
 870   if (java_lang_Thread::thread(java_thread->threadObj()) == NULL) {
 871     // check again because we can get delayed in java_suspend():
 872     // the thread is in process of exiting.
 873     return false;
 874   }
 875 
 876   return true;
 877 }
 878 
 879 bool JvmtiSuspendControl::resume(JavaThread *java_thread) {
 880   // external suspend should have caught resuming a thread twice
 881   assert(java_thread->is_being_ext_suspended(), "thread should be suspended");
 882 
 883   // resume thread
 884   {
 885     // must always grab Threads_lock, see JVM_SuspendThread
 886     MutexLocker ml(Threads_lock);
 887     java_thread->java_resume();
 888   }
 889 
 890   return true;
 891 }
 892 
 893 
 894 void JvmtiSuspendControl::print() {
 895 #ifndef PRODUCT
 896   MutexLocker mu(Threads_lock);
 897   ResourceMark rm;
 898 
 899   tty->print("Suspended Threads: [");
 900   for (JavaThread *thread = Threads::first(); thread != NULL; thread = thread->next()) {
 901 #if JVMTI_TRACE
 902     const char *name   = JvmtiTrace::safe_get_thread_name(thread);
 903 #else
 904     const char *name   = "";
 905 #endif /*JVMTI_TRACE */
 906     tty->print("%s(%c ", name, thread->is_being_ext_suspended() ? 'S' : '_');
 907     if (!thread->has_last_Java_frame()) {
 908       tty->print("no stack");
 909     }
 910     tty->print(") ");
 911   }
 912   tty->print_cr("]");
 913 #endif
 914 }
 915 
 916 #ifndef KERNEL
 917 
 918 JvmtiDeferredEvent JvmtiDeferredEvent::compiled_method_load_event(
 919     nmethod* nm) {
 920   JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_COMPILED_METHOD_LOAD);
 921   event._event_data.compiled_method_load = nm;
 922   // Keep the nmethod alive until the ServiceThread can process
 923   // this deferred event.
 924   nmethodLocker::lock_nmethod(nm);
 925   return event;
 926 }
 927 
 928 JvmtiDeferredEvent JvmtiDeferredEvent::compiled_method_unload_event(
 929     nmethod* nm, jmethodID id, const void* code) {
 930   JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_COMPILED_METHOD_UNLOAD);
 931   event._event_data.compiled_method_unload.nm = nm;
 932   event._event_data.compiled_method_unload.method_id = id;
 933   event._event_data.compiled_method_unload.code_begin = code;
 934   // Keep the nmethod alive until the ServiceThread can process
 935   // this deferred event. This will keep the memory for the
 936   // generated code from being reused too early. We pass
 937   // zombie_ok == true here so that our nmethod that was just
 938   // made into a zombie can be locked. 
 939   nmethodLocker::lock_nmethod(nm, true /* zombie_ok */);
 940   return event;
 941 }
 942 JvmtiDeferredEvent JvmtiDeferredEvent::dynamic_code_generated_event(
 943       const char* name, const void* code_begin, const void* code_end) {
 944   JvmtiDeferredEvent event = JvmtiDeferredEvent(TYPE_DYNAMIC_CODE_GENERATED);
 945   event._event_data.dynamic_code_generated.name = name;
 946   event._event_data.dynamic_code_generated.code_begin = code_begin;
 947   event._event_data.dynamic_code_generated.code_end = code_end;
 948   return event;
 949 }
 950 
 951 void JvmtiDeferredEvent::post() {
 952   assert(ServiceThread::is_service_thread(Thread::current()),
 953          "Service thread must post enqueued events");
 954   switch(_type) {
 955     case TYPE_COMPILED_METHOD_LOAD: {
 956       nmethod* nm = _event_data.compiled_method_load;
 957       JvmtiExport::post_compiled_method_load(nm);
 958       // done with the deferred event so unlock the nmethod
 959       nmethodLocker::unlock_nmethod(nm);
 960       break;
 961     }
 962     case TYPE_COMPILED_METHOD_UNLOAD: {
 963       nmethod* nm = _event_data.compiled_method_unload.nm;
 964       JvmtiExport::post_compiled_method_unload(
 965         _event_data.compiled_method_unload.method_id,
 966         _event_data.compiled_method_unload.code_begin);
 967       // done with the deferred event so unlock the nmethod
 968       nmethodLocker::unlock_nmethod(nm);
 969       break;
 970     }
 971     case TYPE_DYNAMIC_CODE_GENERATED:
 972       JvmtiExport::post_dynamic_code_generated_internal(
 973         _event_data.dynamic_code_generated.name,
 974         _event_data.dynamic_code_generated.code_begin,
 975         _event_data.dynamic_code_generated.code_end);
 976       break;
 977     default:
 978       ShouldNotReachHere();
 979   }
 980 }
 981 
 982 JvmtiDeferredEventQueue::QueueNode* JvmtiDeferredEventQueue::_queue_tail = NULL;
 983 JvmtiDeferredEventQueue::QueueNode* JvmtiDeferredEventQueue::_queue_head = NULL;
 984 
 985 volatile JvmtiDeferredEventQueue::QueueNode*
 986     JvmtiDeferredEventQueue::_pending_list = NULL;
 987 
 988 bool JvmtiDeferredEventQueue::has_events() {
 989   assert(Service_lock->owned_by_self(), "Must own Service_lock");
 990   return _queue_head != NULL || _pending_list != NULL;
 991 }
 992 
 993 void JvmtiDeferredEventQueue::enqueue(const JvmtiDeferredEvent& event) {
 994   assert(Service_lock->owned_by_self(), "Must own Service_lock");
 995 
 996   process_pending_events();
 997 
 998   // Events get added to the end of the queue (and are pulled off the front).
 999   QueueNode* node = new QueueNode(event);
1000   if (_queue_tail == NULL) {
1001     _queue_tail = _queue_head = node;
1002   } else {
1003     assert(_queue_tail->next() == NULL, "Must be the last element in the list");
1004     _queue_tail->set_next(node);
1005     _queue_tail = node;
1006   }
1007 
1008   Service_lock->notify_all();
1009   assert((_queue_head == NULL) == (_queue_tail == NULL),
1010          "Inconsistent queue markers");
1011 }
1012 
1013 JvmtiDeferredEvent JvmtiDeferredEventQueue::dequeue() {
1014   assert(Service_lock->owned_by_self(), "Must own Service_lock");
1015 
1016   process_pending_events();
1017 
1018   assert(_queue_head != NULL, "Nothing to dequeue");
1019 
1020   if (_queue_head == NULL) {
1021     // Just in case this happens in product; it shouldn't but let's not crash
1022     return JvmtiDeferredEvent();
1023   }
1024 
1025   QueueNode* node = _queue_head;
1026   _queue_head = _queue_head->next();
1027   if (_queue_head == NULL) {
1028     _queue_tail = NULL;
1029   }
1030 
1031   assert((_queue_head == NULL) == (_queue_tail == NULL),
1032          "Inconsistent queue markers");
1033 
1034   JvmtiDeferredEvent event = node->event();
1035   delete node;
1036   return event;
1037 }
1038 
1039 void JvmtiDeferredEventQueue::add_pending_event(
1040     const JvmtiDeferredEvent& event) {
1041 
1042   QueueNode* node = new QueueNode(event);
1043 
1044   bool success = false;
1045   QueueNode* prev_value = (QueueNode*)_pending_list;
1046   do {
1047     node->set_next(prev_value);
1048     prev_value = (QueueNode*)Atomic::cmpxchg_ptr(
1049         (void*)node, (volatile void*)&_pending_list, (void*)node->next());
1050   } while (prev_value != node->next());
1051 }
1052 
1053 // This method transfers any events that were added by someone NOT holding
1054 // the lock into the mainline queue.
1055 void JvmtiDeferredEventQueue::process_pending_events() {
1056   assert(Service_lock->owned_by_self(), "Must own Service_lock");
1057 
1058   if (_pending_list != NULL) {
1059     QueueNode* head =
1060         (QueueNode*)Atomic::xchg_ptr(NULL, (volatile void*)&_pending_list);
1061 
1062     assert((_queue_head == NULL) == (_queue_tail == NULL),
1063            "Inconsistent queue markers");
1064 
1065     if (head != NULL) {
1066       // Since we've treated the pending list as a stack (with newer
1067       // events at the beginning), we need to join the bottom of the stack
1068       // with the 'tail' of the queue in order to get the events in the
1069       // right order.  We do this by reversing the pending list and appending
1070       // it to the queue.
1071 
1072       QueueNode* new_tail = head;
1073       QueueNode* new_head = NULL;
1074 
1075       // This reverses the list
1076       QueueNode* prev = new_tail;
1077       QueueNode* node = new_tail->next();
1078       new_tail->set_next(NULL);
1079       while (node != NULL) {
1080         QueueNode* next = node->next();
1081         node->set_next(prev);
1082         prev = node;
1083         node = next;
1084       }
1085       new_head = prev;
1086 
1087       // Now append the new list to the queue
1088       if (_queue_tail != NULL) {
1089         _queue_tail->set_next(new_head);
1090       } else { // _queue_head == NULL
1091         _queue_head = new_head;
1092       }
1093       _queue_tail = new_tail;
1094     }
1095   }
1096 }
1097 
1098 #endif // ndef KERNEL