1 /*
   2  * Copyright (c) 1997, 2018, 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 "interpreter/interpreter.hpp"
  27 #include "memory/resourceArea.hpp"
  28 #include "memory/universe.hpp"
  29 #include "oops/markOop.hpp"
  30 #include "oops/method.hpp"
  31 #include "oops/oop.inline.hpp"
  32 #include "prims/methodHandles.hpp"
  33 #include "runtime/frame.inline.hpp"
  34 #include "runtime/handles.inline.hpp"
  35 #include "runtime/javaCalls.hpp"
  36 #include "runtime/monitorChunk.hpp"
  37 #include "runtime/os.inline.hpp"
  38 #include "runtime/signature.hpp"
  39 #include "runtime/stubCodeGenerator.hpp"
  40 #include "runtime/stubRoutines.hpp"
  41 #include "vmreg_x86.inline.hpp"
  42 #ifdef COMPILER1
  43 #include "c1/c1_Runtime1.hpp"
  44 #include "runtime/vframeArray.hpp"
  45 #endif
  46 
  47 #ifdef ASSERT
  48 void RegisterMap::check_location_valid() {
  49 }
  50 #endif
  51 
  52 // Profiling/safepoint support
  53 
  54 bool frame::safe_for_sender(JavaThread *thread) {
  55   address   sp = (address)_sp;
  56   address   fp = (address)_fp;
  57   address   unextended_sp = (address)_unextended_sp;
  58 
  59   // consider stack guards when trying to determine "safe" stack pointers
  60   static size_t stack_guard_size = os::uses_stack_guard_pages() ?
  61     JavaThread::stack_red_zone_size() + JavaThread::stack_yellow_zone_size() : 0;
  62   size_t usable_stack_size = thread->stack_size() - stack_guard_size;
  63 
  64   // sp must be within the usable part of the stack (not in guards)
  65   bool sp_safe = (sp < thread->stack_base()) &&
  66                  (sp >= thread->stack_base() - usable_stack_size);
  67 
  68 
  69   if (!sp_safe) {
  70     return false;
  71   }
  72 
  73   // unextended sp must be within the stack and above or equal sp
  74   bool unextended_sp_safe = (unextended_sp < thread->stack_base()) &&
  75                             (unextended_sp >= sp);
  76 
  77   if (!unextended_sp_safe) {
  78     return false;
  79   }
  80 
  81   // an fp must be within the stack and above (but not equal) sp
  82   // second evaluation on fp+ is added to handle situation where fp is -1
  83   bool fp_safe = (fp < thread->stack_base() && (fp > sp) && (((fp + (return_addr_offset * sizeof(void*))) < thread->stack_base())));
  84 
  85   // We know sp/unextended_sp are safe only fp is questionable here
  86 
  87   // If the current frame is known to the code cache then we can attempt to
  88   // to construct the sender and do some validation of it. This goes a long way
  89   // toward eliminating issues when we get in frame construction code
  90 
  91   if (_cb != NULL ) {
  92 
  93     // First check if frame is complete and tester is reliable
  94     // Unfortunately we can only check frame complete for runtime stubs and nmethod
  95     // other generic buffer blobs are more problematic so we just assume they are
  96     // ok. adapter blobs never have a frame complete and are never ok.
  97 
  98     if (!_cb->is_frame_complete_at(_pc)) {
  99       if (_cb->is_compiled() || _cb->is_adapter_blob() || _cb->is_runtime_stub()) {
 100         return false;
 101       }
 102     }
 103 
 104     // Could just be some random pointer within the codeBlob
 105     if (!_cb->code_contains(_pc)) {
 106       return false;
 107     }
 108 
 109     // Entry frame checks
 110     if (is_entry_frame()) {
 111       // an entry frame must have a valid fp.
 112       return fp_safe && is_entry_frame_valid(thread);
 113     }
 114 
 115     intptr_t* sender_sp = NULL;
 116     intptr_t* sender_unextended_sp = NULL;
 117     address   sender_pc = NULL;
 118     intptr_t* saved_fp =  NULL;
 119 
 120     if (is_interpreted_frame()) {
 121       // fp must be safe
 122       if (!fp_safe) {
 123         return false;
 124       }
 125 
 126       sender_pc = (address) this->fp()[return_addr_offset];
 127       // for interpreted frames, the value below is the sender "raw" sp,
 128       // which can be different from the sender unextended sp (the sp seen
 129       // by the sender) because of current frame local variables
 130       sender_sp = (intptr_t*) addr_at(sender_sp_offset);
 131       sender_unextended_sp = (intptr_t*) this->fp()[interpreter_frame_sender_sp_offset];
 132       saved_fp = (intptr_t*) this->fp()[link_offset];
 133 
 134     } else {
 135       // must be some sort of compiled/runtime frame
 136       // fp does not have to be safe (although it could be check for c1?)
 137 
 138       // check for a valid frame_size, otherwise we are unlikely to get a valid sender_pc
 139       if (_cb->frame_size() <= 0) {
 140         return false;
 141       }
 142 
 143       sender_sp = _unextended_sp + _cb->frame_size();
 144       // Is sender_sp safe?
 145       if ((address)sender_sp >= thread->stack_base()) {
 146         return false;
 147       }
 148       sender_unextended_sp = sender_sp;
 149       // On Intel the return_address is always the word on the stack
 150       sender_pc = (address) *(sender_sp-1);
 151       // Note: frame::sender_sp_offset is only valid for compiled frame
 152       saved_fp = (intptr_t*) *(sender_sp - frame::sender_sp_offset);
 153     }
 154 
 155 
 156     // If the potential sender is the interpreter then we can do some more checking
 157     if (Interpreter::contains(sender_pc)) {
 158 
 159       // ebp is always saved in a recognizable place in any code we generate. However
 160       // only if the sender is interpreted/call_stub (c1 too?) are we certain that the saved ebp
 161       // is really a frame pointer.
 162 
 163       bool saved_fp_safe = ((address)saved_fp < thread->stack_base()) && (saved_fp > sender_sp);
 164 
 165       if (!saved_fp_safe) {
 166         return false;
 167       }
 168 
 169       // construct the potential sender
 170 
 171       frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
 172 
 173       return sender.is_interpreted_frame_valid(thread);
 174 
 175     }
 176 
 177     // We must always be able to find a recognizable pc
 178     CodeBlob* sender_blob = CodeCache::find_blob_unsafe(sender_pc);
 179     if (sender_pc == NULL ||  sender_blob == NULL) {
 180       return false;
 181     }
 182 
 183     // Could be a zombie method
 184     if (sender_blob->is_zombie() || sender_blob->is_unloaded()) {
 185       return false;
 186     }
 187 
 188     // Could just be some random pointer within the codeBlob
 189     if (!sender_blob->code_contains(sender_pc)) {
 190       return false;
 191     }
 192 
 193     // We should never be able to see an adapter if the current frame is something from code cache
 194     if (sender_blob->is_adapter_blob()) {
 195       return false;
 196     }
 197 
 198     // Could be the call_stub
 199     if (StubRoutines::returns_to_call_stub(sender_pc)) {
 200       bool saved_fp_safe = ((address)saved_fp < thread->stack_base()) && (saved_fp > sender_sp);
 201 
 202       if (!saved_fp_safe) {
 203         return false;
 204       }
 205 
 206       // construct the potential sender
 207 
 208       frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
 209 
 210       // Validate the JavaCallWrapper an entry frame must have
 211       address jcw = (address)sender.entry_frame_call_wrapper();
 212 
 213       bool jcw_safe = (jcw < thread->stack_base()) && (jcw > (address)sender.fp());
 214 
 215       return jcw_safe;
 216     }
 217 
 218     CompiledMethod* nm = sender_blob->as_compiled_method_or_null();
 219     if (nm != NULL) {
 220         if (nm->is_deopt_mh_entry(sender_pc) || nm->is_deopt_entry(sender_pc) ||
 221             nm->method()->is_method_handle_intrinsic()) {
 222             return false;
 223         }
 224     }
 225 
 226     // If the frame size is 0 something (or less) is bad because every nmethod has a non-zero frame size
 227     // because the return address counts against the callee's frame.
 228 
 229     if (sender_blob->frame_size() <= 0) {
 230       assert(!sender_blob->is_compiled(), "should count return address at least");
 231       return false;
 232     }
 233 
 234     // We should never be able to see anything here except an nmethod. If something in the
 235     // code cache (current frame) is called by an entity within the code cache that entity
 236     // should not be anything but the call stub (already covered), the interpreter (already covered)
 237     // or an nmethod.
 238 
 239     if (!sender_blob->is_compiled()) {
 240         return false;
 241     }
 242 
 243     // Could put some more validation for the potential non-interpreted sender
 244     // frame we'd create by calling sender if I could think of any. Wait for next crash in forte...
 245 
 246     // One idea is seeing if the sender_pc we have is one that we'd expect to call to current cb
 247 
 248     // We've validated the potential sender that would be created
 249     return true;
 250   }
 251 
 252   // Must be native-compiled frame. Since sender will try and use fp to find
 253   // linkages it must be safe
 254 
 255   if (!fp_safe) {
 256     return false;
 257   }
 258 
 259   // Will the pc we fetch be non-zero (which we'll find at the oldest frame)
 260 
 261   if ( (address) this->fp()[return_addr_offset] == NULL) return false;
 262 
 263 
 264   // could try and do some more potential verification of native frame if we could think of some...
 265 
 266   return true;
 267 
 268 }
 269 
 270 
 271 void frame::patch_pc(Thread* thread, address pc) {
 272   address* pc_addr = &(((address*) sp())[-1]);
 273   if (TracePcPatching) {
 274     tty->print_cr("patch_pc at address " INTPTR_FORMAT " [" INTPTR_FORMAT " -> " INTPTR_FORMAT "]",
 275                   p2i(pc_addr), p2i(*pc_addr), p2i(pc));
 276   }
 277   // Either the return address is the original one or we are going to
 278   // patch in the same address that's already there.
 279   assert(_pc == *pc_addr || pc == *pc_addr, "must be");
 280   *pc_addr = pc;
 281   _cb = CodeCache::find_blob(pc);
 282   address original_pc = CompiledMethod::get_deopt_original_pc(this);
 283   if (original_pc != NULL) {
 284     assert(original_pc == _pc, "expected original PC to be stored before patching");
 285     _deopt_state = is_deoptimized;
 286     // leave _pc as is
 287   } else {
 288     _deopt_state = not_deoptimized;
 289     _pc = pc;
 290   }
 291 }
 292 
 293 bool frame::is_interpreted_frame() const  {
 294   return Interpreter::contains(pc());
 295 }
 296 
 297 int frame::frame_size(RegisterMap* map) const {
 298   frame sender = this->sender(map);
 299   return sender.sp() - sp();
 300 }
 301 
 302 intptr_t* frame::entry_frame_argument_at(int offset) const {
 303   // convert offset to index to deal with tsi
 304   int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
 305   // Entry frame's arguments are always in relation to unextended_sp()
 306   return &unextended_sp()[index];
 307 }
 308 
 309 // sender_sp
 310 
 311 intptr_t* frame::interpreter_frame_sender_sp() const {
 312   assert(is_interpreted_frame(), "interpreted frame expected");
 313   return (intptr_t*) at(interpreter_frame_sender_sp_offset);
 314 }
 315 
 316 void frame::set_interpreter_frame_sender_sp(intptr_t* sender_sp) {
 317   assert(is_interpreted_frame(), "interpreted frame expected");
 318   ptr_at_put(interpreter_frame_sender_sp_offset, (intptr_t) sender_sp);
 319 }
 320 
 321 
 322 // monitor elements
 323 
 324 BasicObjectLock* frame::interpreter_frame_monitor_begin() const {
 325   return (BasicObjectLock*) addr_at(interpreter_frame_monitor_block_bottom_offset);
 326 }
 327 
 328 BasicObjectLock* frame::interpreter_frame_monitor_end() const {
 329   BasicObjectLock* result = (BasicObjectLock*) *addr_at(interpreter_frame_monitor_block_top_offset);
 330   // make sure the pointer points inside the frame
 331   assert(sp() <= (intptr_t*) result, "monitor end should be above the stack pointer");
 332   assert((intptr_t*) result < fp(),  "monitor end should be strictly below the frame pointer");
 333   return result;
 334 }
 335 
 336 void frame::interpreter_frame_set_monitor_end(BasicObjectLock* value) {
 337   *((BasicObjectLock**)addr_at(interpreter_frame_monitor_block_top_offset)) = value;
 338 }
 339 
 340 // Used by template based interpreter deoptimization
 341 void frame::interpreter_frame_set_last_sp(intptr_t* sp) {
 342     *((intptr_t**)addr_at(interpreter_frame_last_sp_offset)) = sp;
 343 }
 344 
 345 frame frame::sender_for_entry_frame(RegisterMap* map) const {
 346   assert(map != NULL, "map must be set");
 347   // Java frame called from C; skip all C frames and return top C
 348   // frame of that chunk as the sender
 349   JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
 350   assert(!entry_frame_is_first(), "next Java fp must be non zero");
 351   assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
 352   // Since we are walking the stack now this nested anchor is obviously walkable
 353   // even if it wasn't when it was stacked.
 354   if (!jfa->walkable()) {
 355     // Capture _last_Java_pc (if needed) and mark anchor walkable.
 356     jfa->capture_last_Java_pc();
 357   }
 358   map->clear();
 359   assert(map->include_argument_oops(), "should be set by clear");
 360   vmassert(jfa->last_Java_pc() != NULL, "not walkable");
 361   frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
 362   return fr;
 363 }
 364 
 365 //------------------------------------------------------------------------------
 366 // frame::verify_deopt_original_pc
 367 //
 368 // Verifies the calculated original PC of a deoptimization PC for the
 369 // given unextended SP.
 370 #ifdef ASSERT
 371 void frame::verify_deopt_original_pc(CompiledMethod* nm, intptr_t* unextended_sp) {
 372   frame fr;
 373 
 374   // This is ugly but it's better than to change {get,set}_original_pc
 375   // to take an SP value as argument.  And it's only a debugging
 376   // method anyway.
 377   fr._unextended_sp = unextended_sp;
 378 
 379   address original_pc = nm->get_original_pc(&fr);
 380   assert(nm->insts_contains_inclusive(original_pc),
 381          "original PC must be in the main code section of the the compiled method (or must be immediately following it)");
 382 }
 383 #endif
 384 
 385 //------------------------------------------------------------------------------
 386 // frame::adjust_unextended_sp
 387 #ifdef ASSERT
 388 void frame::adjust_unextended_sp() {
 389   // On x86, sites calling method handle intrinsics and lambda forms are treated
 390   // as any other call site. Therefore, no special action is needed when we are
 391   // returning to any of these call sites.
 392 
 393   if (_cb != NULL) {
 394     CompiledMethod* sender_cm = _cb->as_compiled_method_or_null();
 395     if (sender_cm != NULL) {
 396       // If the sender PC is a deoptimization point, get the original PC.
 397       if (sender_cm->is_deopt_entry(_pc) ||
 398           sender_cm->is_deopt_mh_entry(_pc)) {
 399         verify_deopt_original_pc(sender_cm, _unextended_sp);
 400       }
 401     }
 402   }
 403 }
 404 #endif
 405 
 406 //------------------------------------------------------------------------------
 407 // frame::update_map_with_saved_link
 408 void frame::update_map_with_saved_link(RegisterMap* map, intptr_t** link_addr) {
 409   // The interpreter and compiler(s) always save EBP/RBP in a known
 410   // location on entry. We must record where that location is
 411   // so this if EBP/RBP was live on callout from c2 we can find
 412   // the saved copy no matter what it called.
 413 
 414   // Since the interpreter always saves EBP/RBP if we record where it is then
 415   // we don't have to always save EBP/RBP on entry and exit to c2 compiled
 416   // code, on entry will be enough.
 417   map->set_location(rbp->as_VMReg(), (address) link_addr);
 418 #ifdef AMD64
 419   // this is weird "H" ought to be at a higher address however the
 420   // oopMaps seems to have the "H" regs at the same address and the
 421   // vanilla register.
 422   // XXXX make this go away
 423   if (true) {
 424     map->set_location(rbp->as_VMReg()->next(), (address) link_addr);
 425   }
 426 #endif // AMD64
 427 }
 428 
 429 
 430 //------------------------------------------------------------------------------
 431 // frame::sender_for_interpreter_frame
 432 frame frame::sender_for_interpreter_frame(RegisterMap* map) const {
 433   // SP is the raw SP from the sender after adapter or interpreter
 434   // extension.
 435   intptr_t* sender_sp = this->sender_sp();
 436 
 437   // This is the sp before any possible extension (adapter/locals).
 438   intptr_t* unextended_sp = interpreter_frame_sender_sp();
 439 
 440 #if COMPILER2_OR_JVMCI
 441   if (map->update_map()) {
 442     update_map_with_saved_link(map, (intptr_t**) addr_at(link_offset));
 443   }
 444 #endif // COMPILER2_OR_JVMCI
 445 
 446   return frame(sender_sp, unextended_sp, link(), sender_pc());
 447 }
 448 
 449 
 450 //------------------------------------------------------------------------------
 451 // frame::sender_for_compiled_frame
 452 frame frame::sender_for_compiled_frame(RegisterMap* map) const {
 453   assert(map != NULL, "map must be set");
 454 
 455   // frame owned by optimizing compiler
 456   assert(_cb->frame_size() >= 0, "must have non-zero frame size");
 457   intptr_t* sender_sp = unextended_sp() + _cb->frame_size();
 458   intptr_t* unextended_sp = sender_sp;
 459 
 460   // On Intel the return_address is always the word on the stack
 461   address sender_pc = (address) *(sender_sp-1);
 462 
 463   // This is the saved value of EBP which may or may not really be an FP.
 464   // It is only an FP if the sender is an interpreter frame (or C1?).
 465   intptr_t** saved_fp_addr = (intptr_t**) (sender_sp - frame::sender_sp_offset);
 466 
 467   if (map->update_map()) {
 468     // Tell GC to use argument oopmaps for some runtime stubs that need it.
 469     // For C1, the runtime stub might not have oop maps, so set this flag
 470     // outside of update_register_map.
 471     map->set_include_argument_oops(_cb->caller_must_gc_arguments(map->thread()));
 472     if (_cb->oop_maps() != NULL) {
 473       OopMapSet::update_register_map(this, map);
 474     }
 475 
 476     // Since the prolog does the save and restore of EBP there is no oopmap
 477     // for it so we must fill in its location as if there was an oopmap entry
 478     // since if our caller was compiled code there could be live jvm state in it.
 479     update_map_with_saved_link(map, saved_fp_addr);
 480   }
 481 
 482   assert(sender_sp != sp(), "must have changed");
 483   return frame(sender_sp, unextended_sp, *saved_fp_addr, sender_pc);
 484 }
 485 
 486 
 487 //------------------------------------------------------------------------------
 488 // frame::sender
 489 frame frame::sender(RegisterMap* map) const {
 490   // Default is we done have to follow them. The sender_for_xxx will
 491   // update it accordingly
 492   map->set_include_argument_oops(false);
 493 
 494   if (is_entry_frame())       return sender_for_entry_frame(map);
 495   if (is_interpreted_frame()) return sender_for_interpreter_frame(map);
 496   assert(_cb == CodeCache::find_blob(pc()),"Must be the same");
 497 
 498   if (_cb != NULL) {
 499     return sender_for_compiled_frame(map);
 500   }
 501   // Must be native-compiled frame, i.e. the marshaling code for native
 502   // methods that exists in the core system.
 503   return frame(sender_sp(), link(), sender_pc());
 504 }
 505 
 506 bool frame::is_interpreted_frame_valid(JavaThread* thread) const {
 507   assert(is_interpreted_frame(), "Not an interpreted frame");
 508   // These are reasonable sanity checks
 509   if (fp() == 0 || (intptr_t(fp()) & (wordSize-1)) != 0) {
 510     return false;
 511   }
 512   if (sp() == 0 || (intptr_t(sp()) & (wordSize-1)) != 0) {
 513     return false;
 514   }
 515   if (fp() + interpreter_frame_initial_sp_offset < sp()) {
 516     return false;
 517   }
 518   // These are hacks to keep us out of trouble.
 519   // The problem with these is that they mask other problems
 520   if (fp() <= sp()) {        // this attempts to deal with unsigned comparison above
 521     return false;
 522   }
 523 
 524   // do some validation of frame elements
 525   // first the method
 526 
 527   Method* m = *interpreter_frame_method_addr();
 528 
 529   // validate the method we'd find in this potential sender
 530   if (!Method::is_valid_method(m)) return false;
 531 
 532   // stack frames shouldn't be much larger than max_stack elements
 533   // this test requires the use the unextended_sp which is the sp as seen by
 534   // the current frame, and not sp which is the "raw" pc which could point
 535   // further because of local variables of the callee method inserted after
 536   // method arguments
 537   if (fp() - unextended_sp() > 1024 + m->max_stack()*Interpreter::stackElementSize) {
 538     return false;
 539   }
 540 
 541   // validate bci/bcp
 542 
 543   address bcp = interpreter_frame_bcp();
 544   if (m->validate_bci_from_bcp(bcp) < 0) {
 545     return false;
 546   }
 547 
 548   // validate ConstantPoolCache*
 549   ConstantPoolCache* cp = *interpreter_frame_cache_addr();
 550   if (MetaspaceObj::is_valid(cp) == false) return false;
 551 
 552   // validate locals
 553 
 554   address locals =  (address) *interpreter_frame_locals_addr();
 555 
 556   if (locals > thread->stack_base() || locals < (address) fp()) return false;
 557 
 558   // We'd have to be pretty unlucky to be mislead at this point
 559   return true;
 560 }
 561 
 562 BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
 563   assert(is_interpreted_frame(), "interpreted frame expected");
 564   Method* method = interpreter_frame_method();
 565   BasicType type = method->result_type();
 566 
 567   intptr_t* tos_addr;
 568   if (method->is_native()) {
 569     // Prior to calling into the runtime to report the method_exit the possible
 570     // return value is pushed to the native stack. If the result is a jfloat/jdouble
 571     // then ST0 is saved before EAX/EDX. See the note in generate_native_result
 572     tos_addr = (intptr_t*)sp();
 573     if (type == T_FLOAT || type == T_DOUBLE) {
 574     // QQQ seems like this code is equivalent on the two platforms
 575 #ifdef AMD64
 576       // This is times two because we do a push(ltos) after pushing XMM0
 577       // and that takes two interpreter stack slots.
 578       tos_addr += 2 * Interpreter::stackElementWords;
 579 #else
 580       tos_addr += 2;
 581 #endif // AMD64
 582     }
 583   } else {
 584     tos_addr = (intptr_t*)interpreter_frame_tos_address();
 585   }
 586 
 587   switch (type) {
 588     case T_OBJECT  :
 589     case T_ARRAY   : {
 590       oop obj;
 591       if (method->is_native()) {
 592         obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
 593       } else {
 594         oop* obj_p = (oop*)tos_addr;
 595         obj = (obj_p == NULL) ? (oop)NULL : *obj_p;
 596       }
 597       assert(obj == NULL || Universe::heap()->is_in(obj), "sanity check");
 598       *oop_result = obj;
 599       break;
 600     }
 601     case T_BOOLEAN : value_result->z = *(jboolean*)tos_addr; break;
 602     case T_BYTE    : value_result->b = *(jbyte*)tos_addr; break;
 603     case T_CHAR    : value_result->c = *(jchar*)tos_addr; break;
 604     case T_SHORT   : value_result->s = *(jshort*)tos_addr; break;
 605     case T_INT     : value_result->i = *(jint*)tos_addr; break;
 606     case T_LONG    : value_result->j = *(jlong*)tos_addr; break;
 607     case T_FLOAT   : {
 608 #ifdef AMD64
 609         value_result->f = *(jfloat*)tos_addr;
 610 #else
 611       if (method->is_native()) {
 612         jdouble d = *(jdouble*)tos_addr;  // Result was in ST0 so need to convert to jfloat
 613         value_result->f = (jfloat)d;
 614       } else {
 615         value_result->f = *(jfloat*)tos_addr;
 616       }
 617 #endif // AMD64
 618       break;
 619     }
 620     case T_DOUBLE  : value_result->d = *(jdouble*)tos_addr; break;
 621     case T_VOID    : /* Nothing to do */ break;
 622     default        : ShouldNotReachHere();
 623   }
 624 
 625   return type;
 626 }
 627 
 628 
 629 intptr_t* frame::interpreter_frame_tos_at(jint offset) const {
 630   int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
 631   return &interpreter_frame_tos_address()[index];
 632 }
 633 
 634 #ifndef PRODUCT
 635 
 636 #define DESCRIBE_FP_OFFSET(name) \
 637   values.describe(frame_no, fp() + frame::name##_offset, #name)
 638 
 639 void frame::describe_pd(FrameValues& values, int frame_no) {
 640   if (is_interpreted_frame()) {
 641     DESCRIBE_FP_OFFSET(interpreter_frame_sender_sp);
 642     DESCRIBE_FP_OFFSET(interpreter_frame_last_sp);
 643     DESCRIBE_FP_OFFSET(interpreter_frame_method);
 644     DESCRIBE_FP_OFFSET(interpreter_frame_mirror);
 645     DESCRIBE_FP_OFFSET(interpreter_frame_mdp);
 646     DESCRIBE_FP_OFFSET(interpreter_frame_cache);
 647     DESCRIBE_FP_OFFSET(interpreter_frame_locals);
 648     DESCRIBE_FP_OFFSET(interpreter_frame_bcp);
 649     DESCRIBE_FP_OFFSET(interpreter_frame_initial_sp);
 650 #ifdef AMD64
 651   } else if (is_entry_frame()) {
 652     // This could be more descriptive if we use the enum in
 653     // stubGenerator to map to real names but it's most important to
 654     // claim these frame slots so the error checking works.
 655     for (int i = 0; i < entry_frame_after_call_words; i++) {
 656       values.describe(frame_no, fp() - i, err_msg("call_stub word fp - %d", i));
 657     }
 658 #endif // AMD64
 659   }
 660 }
 661 #endif // !PRODUCT
 662 
 663 intptr_t *frame::initial_deoptimization_info() {
 664   // used to reset the saved FP
 665   return fp();
 666 }
 667 
 668 intptr_t* frame::real_fp() const {
 669   if (_cb != NULL) {
 670     // use the frame size if valid
 671     int size = _cb->frame_size();
 672     if (size > 0) {
 673       return unextended_sp() + size;
 674     }
 675   }
 676   // else rely on fp()
 677   assert(! is_compiled_frame(), "unknown compiled frame size");
 678   return fp();
 679 }
 680 
 681 #ifndef PRODUCT
 682 // This is a generic constructor which is only used by pns() in debug.cpp.
 683 frame::frame(void* sp, void* fp, void* pc) {
 684   init((intptr_t*)sp, (intptr_t*)fp, (address)pc);
 685 }
 686 
 687 void frame::pd_ps() {}
 688 #endif
 689 
 690 void JavaFrameAnchor::make_walkable(JavaThread* thread) {
 691   // last frame set?
 692   if (last_Java_sp() == NULL) return;
 693   // already walkable?
 694   if (walkable()) return;
 695   vmassert(Thread::current() == (Thread*)thread, "not current thread");
 696   vmassert(last_Java_sp() != NULL, "not called from Java code?");
 697   vmassert(last_Java_pc() == NULL, "already walkable");
 698   capture_last_Java_pc();
 699   vmassert(walkable(), "something went wrong");
 700 }
 701 
 702 void JavaFrameAnchor::capture_last_Java_pc() {
 703   vmassert(_last_Java_sp != NULL, "no last frame set");
 704   vmassert(_last_Java_pc == NULL, "already walkable");
 705   _last_Java_pc = (address)_last_Java_sp[-1];
 706 }