1 /*
  2  * Copyright (c) 1997, 2023, 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 "compiler/oopMap.hpp"
 27 #include "interpreter/interpreter.hpp"
 28 #include "memory/resourceArea.hpp"
 29 #include "memory/universe.hpp"
 30 #include "oops/markWord.hpp"
 31 #include "oops/method.hpp"
 32 #include "oops/oop.inline.hpp"
 33 #include "prims/methodHandles.hpp"
 34 #include "runtime/continuation.hpp"
 35 #include "runtime/frame.inline.hpp"
 36 #include "runtime/handles.inline.hpp"
 37 #include "runtime/javaCalls.hpp"
 38 #include "runtime/monitorChunk.hpp"
 39 #include "runtime/signature.hpp"
 40 #include "runtime/stackWatermarkSet.hpp"
 41 #include "runtime/stubCodeGenerator.hpp"
 42 #include "runtime/stubRoutines.hpp"
 43 #include "vmreg_x86.inline.hpp"
 44 #include "utilities/formatBuffer.hpp"
 45 #ifdef COMPILER1
 46 #include "c1/c1_Runtime1.hpp"
 47 #include "runtime/vframeArray.hpp"
 48 #endif
 49 
 50 #ifdef ASSERT
 51 void RegisterMap::check_location_valid() {
 52 }
 53 #endif
 54 
 55 // Profiling/safepoint support
 56 
 57 bool frame::safe_for_sender(JavaThread *thread) {
 58   if (is_heap_frame()) {
 59     return true;
 60   }
 61   address   sp = (address)_sp;
 62   address   fp = (address)_fp;
 63   address   unextended_sp = (address)_unextended_sp;
 64 
 65   // consider stack guards when trying to determine "safe" stack pointers
 66   // sp must be within the usable part of the stack (not in guards)
 67   if (!thread->is_in_usable_stack(sp)) {
 68     return false;
 69   }
 70 
 71   // unextended sp must be within the stack
 72   // Note: sp can be greater than unextended_sp in the case of
 73   // interpreted -> interpreted calls that go through a method handle linker,
 74   // since those pop the last argument (the appendix) from the stack.
 75   if (!thread->is_in_stack_range_incl(unextended_sp, sp - Interpreter::stackElementSize)) {
 76     return false;
 77   }
 78 
 79   // an fp must be within the stack and above (but not equal) sp
 80   // second evaluation on fp+ is added to handle situation where fp is -1
 81   bool fp_safe = thread->is_in_stack_range_excl(fp, sp) &&
 82                  thread->is_in_full_stack_checked(fp + (return_addr_offset * sizeof(void*)));
 83 
 84   // We know sp/unextended_sp are safe only fp is questionable here
 85 
 86   // If the current frame is known to the code cache then we can attempt to
 87   // construct the sender and do some validation of it. This goes a long way
 88   // toward eliminating issues when we get in frame construction code
 89 
 90   if (_cb != nullptr ) {
 91 
 92     // First check if frame is complete and tester is reliable
 93     // Unfortunately we can only check frame complete for runtime stubs and nmethod
 94     // other generic buffer blobs are more problematic so we just assume they are
 95     // ok. adapter blobs never have a frame complete and are never ok.
 96 
 97     if (!_cb->is_frame_complete_at(_pc)) {
 98       if (_cb->is_compiled() || _cb->is_adapter_blob() || _cb->is_runtime_stub()) {
 99         return false;
100       }
101     }
102 
103     // Could just be some random pointer within the codeBlob
104     if (!_cb->code_contains(_pc)) {
105       return false;
106     }
107 
108     // Entry frame checks
109     if (is_entry_frame()) {
110       // an entry frame must have a valid fp.
111       return fp_safe && is_entry_frame_valid(thread);
112     } else if (is_upcall_stub_frame()) {
113       return fp_safe;
114     }
115 
116     intptr_t* sender_sp = nullptr;
117     intptr_t* sender_unextended_sp = nullptr;
118     address   sender_pc = nullptr;
119     intptr_t* saved_fp =  nullptr;
120 
121     if (is_interpreted_frame()) {
122       // fp must be safe
123       if (!fp_safe) {
124         return false;
125       }
126 
127       sender_pc = (address) this->fp()[return_addr_offset];
128       // for interpreted frames, the value below is the sender "raw" sp,
129       // which can be different from the sender unextended sp (the sp seen
130       // by the sender) because of current frame local variables
131       sender_sp = (intptr_t*) addr_at(sender_sp_offset);
132       sender_unextended_sp = (intptr_t*) this->fp()[interpreter_frame_sender_sp_offset];
133       saved_fp = (intptr_t*) this->fp()[link_offset];
134 
135     } else {
136       // must be some sort of compiled/runtime frame
137       // fp does not have to be safe (although it could be check for c1?)
138 
139       // check for a valid frame_size, otherwise we are unlikely to get a valid sender_pc
140       if (_cb->frame_size() <= 0) {
141         return false;
142       }
143 
144       sender_sp = _unextended_sp + _cb->frame_size();
145       // Is sender_sp safe?
146       if (!thread->is_in_full_stack_checked((address)sender_sp)) {
147         return false;
148       }
149       sender_unextended_sp = sender_sp;
150       // On Intel the return_address is always the word on the stack
151       sender_pc = (address) *(sender_sp-1);
152       // Note: frame::sender_sp_offset is only valid for compiled frame
153       saved_fp = (intptr_t*) *(sender_sp - frame::sender_sp_offset);
154     }
155 
156     if (Continuation::is_return_barrier_entry(sender_pc)) {
157       // If our sender_pc is the return barrier, then our "real" sender is the continuation entry
158       frame s = Continuation::continuation_bottom_sender(thread, *this, sender_sp);
159       sender_sp = s.sp();
160       sender_pc = s.pc();
161     }
162 
163     // If the potential sender is the interpreter then we can do some more checking
164     if (Interpreter::contains(sender_pc)) {
165 
166       // ebp is always saved in a recognizable place in any code we generate. However
167       // only if the sender is interpreted/call_stub (c1 too?) are we certain that the saved ebp
168       // is really a frame pointer.
169 
170       if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) {
171         return false;
172       }
173 
174       // construct the potential sender
175 
176       frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
177 
178       return sender.is_interpreted_frame_valid(thread);
179 
180     }
181 
182     // We must always be able to find a recognizable pc
183     CodeBlob* sender_blob = CodeCache::find_blob(sender_pc);
184     if (sender_pc == nullptr ||  sender_blob == nullptr) {
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       if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) {
201         return false;
202       }
203 
204       // construct the potential sender
205 
206       frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
207 
208       // Validate the JavaCallWrapper an entry frame must have
209       address jcw = (address)sender.entry_frame_call_wrapper();
210 
211       return thread->is_in_stack_range_excl(jcw, (address)sender.fp());
212     } else if (sender_blob->is_upcall_stub()) {
213       return false;
214     }
215 
216     CompiledMethod* nm = sender_blob->as_compiled_method_or_null();
217     if (nm != nullptr) {
218         if (nm->is_deopt_mh_entry(sender_pc) || nm->is_deopt_entry(sender_pc) ||
219             nm->method()->is_method_handle_intrinsic()) {
220             return false;
221         }
222     }
223 
224     // If the frame size is 0 something (or less) is bad because every nmethod has a non-zero frame size
225     // because the return address counts against the callee's frame.
226 
227     if (sender_blob->frame_size() <= 0) {
228       assert(!sender_blob->is_compiled(), "should count return address at least");
229       return false;
230     }
231 
232     // We should never be able to see anything here except an nmethod. If something in the
233     // code cache (current frame) is called by an entity within the code cache that entity
234     // should not be anything but the call stub (already covered), the interpreter (already covered)
235     // or an nmethod.
236 
237     if (!sender_blob->is_compiled()) {
238         return false;
239     }
240 
241     // Could put some more validation for the potential non-interpreted sender
242     // frame we'd create by calling sender if I could think of any. Wait for next crash in forte...
243 
244     // One idea is seeing if the sender_pc we have is one that we'd expect to call to current cb
245 
246     // We've validated the potential sender that would be created
247     return true;
248   }
249 
250   // Must be native-compiled frame. Since sender will try and use fp to find
251   // linkages it must be safe
252 
253   if (!fp_safe) {
254     return false;
255   }
256 
257   // Will the pc we fetch be non-zero (which we'll find at the oldest frame)
258 
259   if ( (address) this->fp()[return_addr_offset] == nullptr) return false;
260 
261 
262   // could try and do some more potential verification of native frame if we could think of some...
263 
264   return true;
265 
266 }
267 
268 
269 void frame::patch_pc(Thread* thread, address pc) {
270   assert(_cb == CodeCache::find_blob(pc), "unexpected pc");
271   address* pc_addr = &(((address*) sp())[-1]);
272 
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 
280   assert(!Continuation::is_return_barrier_entry(*pc_addr), "return barrier");
281 
282   assert(_pc == *pc_addr || pc == *pc_addr || *pc_addr == 0, "");
283   DEBUG_ONLY(address old_pc = _pc;)
284   *pc_addr = pc;
285   _pc = pc; // must be set before call to get_deopt_original_pc
286   address original_pc = CompiledMethod::get_deopt_original_pc(this);
287   if (original_pc != nullptr) {
288     assert(original_pc == old_pc, "expected original PC to be stored before patching");
289     _deopt_state = is_deoptimized;
290     _pc = original_pc;
291   } else {
292     _deopt_state = not_deoptimized;
293   }
294   assert(!is_compiled_frame() || !_cb->as_compiled_method()->is_deopt_entry(_pc), "must be");
295 
296 #ifdef ASSERT
297   {
298     frame f(this->sp(), this->unextended_sp(), this->fp(), pc);
299     assert(f.is_deoptimized_frame() == this->is_deoptimized_frame() && f.pc() == this->pc() && f.raw_pc() == this->raw_pc(),
300       "must be (f.is_deoptimized_frame(): %d this->is_deoptimized_frame(): %d "
301       "f.pc(): " INTPTR_FORMAT " this->pc(): " INTPTR_FORMAT " f.raw_pc(): " INTPTR_FORMAT " this->raw_pc(): " INTPTR_FORMAT ")",
302       f.is_deoptimized_frame(), this->is_deoptimized_frame(), p2i(f.pc()), p2i(this->pc()), p2i(f.raw_pc()), p2i(this->raw_pc()));
303   }
304 #endif
305 }
306 
307 intptr_t* frame::entry_frame_argument_at(int offset) const {
308   // convert offset to index to deal with tsi
309   int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
310   // Entry frame's arguments are always in relation to unextended_sp()
311   return &unextended_sp()[index];
312 }
313 
314 // locals
315 
316 void frame::interpreter_frame_set_locals(intptr_t* locs)  {
317   assert(is_interpreted_frame(), "interpreted frame expected");
318   // set relativized locals
319   ptr_at_put(interpreter_frame_locals_offset, (intptr_t) (locs - fp()));
320 }
321 
322 // sender_sp
323 
324 intptr_t* frame::interpreter_frame_sender_sp() const {
325   assert(is_interpreted_frame(), "interpreted frame expected");
326   return (intptr_t*) at(interpreter_frame_sender_sp_offset);
327 }
328 
329 void frame::set_interpreter_frame_sender_sp(intptr_t* sender_sp) {
330   assert(is_interpreted_frame(), "interpreted frame expected");
331   ptr_at_put(interpreter_frame_sender_sp_offset, (intptr_t) sender_sp);
332 }
333 
334 
335 // monitor elements
336 
337 BasicObjectLock* frame::interpreter_frame_monitor_begin() const {
338   return (BasicObjectLock*) addr_at(interpreter_frame_monitor_block_bottom_offset);
339 }
340 
341 BasicObjectLock* frame::interpreter_frame_monitor_end() const {
342   BasicObjectLock* result = (BasicObjectLock*) at_relative(interpreter_frame_monitor_block_top_offset);
343   // make sure the pointer points inside the frame
344   assert(sp() <= (intptr_t*) result, "monitor end should be above the stack pointer");
345   assert((intptr_t*) result < fp(),  "monitor end should be strictly below the frame pointer: result: " INTPTR_FORMAT " fp: " INTPTR_FORMAT, p2i(result), p2i(fp()));
346   return result;
347 }
348 
349 void frame::interpreter_frame_set_monitor_end(BasicObjectLock* value) {
350   assert(is_interpreted_frame(), "interpreted frame expected");
351   // set relativized monitor_block_top
352   ptr_at_put(interpreter_frame_monitor_block_top_offset, (intptr_t*)value - fp());
353   assert(at_absolute(interpreter_frame_monitor_block_top_offset) <= interpreter_frame_monitor_block_top_offset, "");
354 }
355 
356 // Used by template based interpreter deoptimization
357 void frame::interpreter_frame_set_last_sp(intptr_t* sp) {
358   assert(is_interpreted_frame(), "interpreted frame expected");
359   // set relativized last_sp
360   ptr_at_put(interpreter_frame_last_sp_offset, sp != nullptr ? (sp - fp()) : 0);
361 }
362 
363 frame frame::sender_for_entry_frame(RegisterMap* map) const {
364   assert(map != nullptr, "map must be set");
365   // Java frame called from C; skip all C frames and return top C
366   // frame of that chunk as the sender
367   JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
368   assert(!entry_frame_is_first(), "next Java fp must be non zero");
369   assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
370   // Since we are walking the stack now this nested anchor is obviously walkable
371   // even if it wasn't when it was stacked.
372   jfa->make_walkable();
373   map->clear();
374   assert(map->include_argument_oops(), "should be set by clear");
375   frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
376 
377   return fr;
378 }
379 
380 UpcallStub::FrameData* UpcallStub::frame_data_for_frame(const frame& frame) const {
381   assert(frame.is_upcall_stub_frame(), "wrong frame");
382   // need unextended_sp here, since normal sp is wrong for interpreter callees
383   return reinterpret_cast<UpcallStub::FrameData*>(
384     reinterpret_cast<address>(frame.unextended_sp()) + in_bytes(_frame_data_offset));
385 }
386 
387 bool frame::upcall_stub_frame_is_first() const {
388   assert(is_upcall_stub_frame(), "must be optimzed entry frame");
389   UpcallStub* blob = _cb->as_upcall_stub();
390   JavaFrameAnchor* jfa = blob->jfa_for_frame(*this);
391   return jfa->last_Java_sp() == nullptr;
392 }
393 
394 frame frame::sender_for_upcall_stub_frame(RegisterMap* map) const {
395   assert(map != nullptr, "map must be set");
396   UpcallStub* blob = _cb->as_upcall_stub();
397   // Java frame called from C; skip all C frames and return top C
398   // frame of that chunk as the sender
399   JavaFrameAnchor* jfa = blob->jfa_for_frame(*this);
400   assert(!upcall_stub_frame_is_first(), "must have a frame anchor to go back to");
401   assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
402   // Since we are walking the stack now this nested anchor is obviously walkable
403   // even if it wasn't when it was stacked.
404   jfa->make_walkable();
405   map->clear();
406   assert(map->include_argument_oops(), "should be set by clear");
407   frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
408 
409   return fr;
410 }
411 
412 //------------------------------------------------------------------------------
413 // frame::verify_deopt_original_pc
414 //
415 // Verifies the calculated original PC of a deoptimization PC for the
416 // given unextended SP.
417 #ifdef ASSERT
418 void frame::verify_deopt_original_pc(CompiledMethod* nm, intptr_t* unextended_sp) {
419   frame fr;
420 
421   // This is ugly but it's better than to change {get,set}_original_pc
422   // to take an SP value as argument.  And it's only a debugging
423   // method anyway.
424   fr._unextended_sp = unextended_sp;
425 
426   address original_pc = nm->get_original_pc(&fr);
427   assert(nm->insts_contains_inclusive(original_pc),
428          "original PC must be in the main code section of the compiled method (or must be immediately following it) original_pc: " INTPTR_FORMAT " unextended_sp: " INTPTR_FORMAT " name: %s", p2i(original_pc), p2i(unextended_sp), nm->name());
429 }
430 #endif
431 
432 //------------------------------------------------------------------------------
433 // frame::adjust_unextended_sp
434 #ifdef ASSERT
435 void frame::adjust_unextended_sp() {
436   // On x86, sites calling method handle intrinsics and lambda forms are treated
437   // as any other call site. Therefore, no special action is needed when we are
438   // returning to any of these call sites.
439 
440   if (_cb != nullptr) {
441     CompiledMethod* sender_cm = _cb->as_compiled_method_or_null();
442     if (sender_cm != nullptr) {
443       // If the sender PC is a deoptimization point, get the original PC.
444       if (sender_cm->is_deopt_entry(_pc) ||
445           sender_cm->is_deopt_mh_entry(_pc)) {
446         verify_deopt_original_pc(sender_cm, _unextended_sp);
447       }
448     }
449   }
450 }
451 #endif
452 
453 //------------------------------------------------------------------------------
454 // frame::sender_for_interpreter_frame
455 frame frame::sender_for_interpreter_frame(RegisterMap* map) const {
456   // SP is the raw SP from the sender after adapter or interpreter
457   // extension.
458   intptr_t* sender_sp = this->sender_sp();
459 
460   // This is the sp before any possible extension (adapter/locals).
461   intptr_t* unextended_sp = interpreter_frame_sender_sp();
462   intptr_t* sender_fp = link();
463 
464 #if COMPILER2_OR_JVMCI
465   if (map->update_map()) {
466     update_map_with_saved_link(map, (intptr_t**) addr_at(link_offset));
467   }
468 #endif // COMPILER2_OR_JVMCI
469 
470   address sender_pc = this->sender_pc();
471 
472   if (Continuation::is_return_barrier_entry(sender_pc)) {
473     if (map->walk_cont()) { // about to walk into an h-stack
474       return Continuation::top_frame(*this, map);
475     } else {
476       return Continuation::continuation_bottom_sender(map->thread(), *this, sender_sp);
477     }
478   }
479 
480   return frame(sender_sp, unextended_sp, sender_fp, sender_pc);
481 }
482 
483 bool frame::is_interpreted_frame_valid(JavaThread* thread) const {
484   assert(is_interpreted_frame(), "Not an interpreted frame");
485   // These are reasonable sanity checks
486   if (fp() == 0 || (intptr_t(fp()) & (wordSize-1)) != 0) {
487     return false;
488   }
489   if (sp() == 0 || (intptr_t(sp()) & (wordSize-1)) != 0) {
490     return false;
491   }
492   if (fp() + interpreter_frame_initial_sp_offset < sp()) {
493     return false;
494   }
495   // These are hacks to keep us out of trouble.
496   // The problem with these is that they mask other problems
497   if (fp() <= sp()) {        // this attempts to deal with unsigned comparison above
498     return false;
499   }
500 
501   // do some validation of frame elements
502   // first the method
503 
504   Method* m = safe_interpreter_frame_method();
505 
506   // validate the method we'd find in this potential sender
507   if (!Method::is_valid_method(m)) return false;
508 
509   // stack frames shouldn't be much larger than max_stack elements
510   // this test requires the use the unextended_sp which is the sp as seen by
511   // the current frame, and not sp which is the "raw" pc which could point
512   // further because of local variables of the callee method inserted after
513   // method arguments
514   if (fp() - unextended_sp() > 1024 + m->max_stack()*Interpreter::stackElementSize) {
515     return false;
516   }
517 
518   // validate bci/bcp
519 
520   address bcp = interpreter_frame_bcp();
521   if (m->validate_bci_from_bcp(bcp) < 0) {
522     return false;
523   }
524 
525   // validate ConstantPoolCache*
526   ConstantPoolCache* cp = *interpreter_frame_cache_addr();
527   if (MetaspaceObj::is_valid(cp) == false) return false;
528 
529   // validate locals
530 
531   address locals =  (address)interpreter_frame_locals();
532   return thread->is_in_stack_range_incl(locals, (address)fp());
533 }
534 
535 BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
536   assert(is_interpreted_frame(), "interpreted frame expected");
537   Method* method = interpreter_frame_method();
538   BasicType type = method->result_type();
539 
540   intptr_t* tos_addr;
541   if (method->is_native()) {
542     // Prior to calling into the runtime to report the method_exit the possible
543     // return value is pushed to the native stack. If the result is a jfloat/jdouble
544     // then ST0 is saved before EAX/EDX. See the note in generate_native_result
545     tos_addr = (intptr_t*)sp();
546     if (type == T_FLOAT || type == T_DOUBLE) {
547     // QQQ seems like this code is equivalent on the two platforms
548 #ifdef AMD64
549       // This is times two because we do a push(ltos) after pushing XMM0
550       // and that takes two interpreter stack slots.
551       tos_addr += 2 * Interpreter::stackElementWords;
552 #else
553       tos_addr += 2;
554 #endif // AMD64
555     }
556   } else {
557     tos_addr = (intptr_t*)interpreter_frame_tos_address();
558   }
559 
560   switch (type) {
561     case T_OBJECT  :
562     case T_ARRAY   : {
563       oop obj;
564       if (method->is_native()) {
565         obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
566       } else {
567         oop* obj_p = (oop*)tos_addr;
568         obj = (obj_p == nullptr) ? (oop)nullptr : *obj_p;
569       }
570       assert(Universe::is_in_heap_or_null(obj), "sanity check");
571       *oop_result = obj;
572       break;
573     }
574     case T_BOOLEAN : value_result->z = *(jboolean*)tos_addr; break;
575     case T_BYTE    : value_result->b = *(jbyte*)tos_addr; break;
576     case T_CHAR    : value_result->c = *(jchar*)tos_addr; break;
577     case T_SHORT   : value_result->s = *(jshort*)tos_addr; break;
578     case T_INT     : value_result->i = *(jint*)tos_addr; break;
579     case T_LONG    : value_result->j = *(jlong*)tos_addr; break;
580     case T_FLOAT   : {
581 #ifdef AMD64
582         value_result->f = *(jfloat*)tos_addr;
583 #else
584       if (method->is_native()) {
585         jdouble d = *(jdouble*)tos_addr;  // Result was in ST0 so need to convert to jfloat
586         value_result->f = (jfloat)d;
587       } else {
588         value_result->f = *(jfloat*)tos_addr;
589       }
590 #endif // AMD64
591       break;
592     }
593     case T_DOUBLE  : value_result->d = *(jdouble*)tos_addr; break;
594     case T_VOID    : /* Nothing to do */ break;
595     default        : ShouldNotReachHere();
596   }
597 
598   return type;
599 }
600 
601 intptr_t* frame::interpreter_frame_tos_at(jint offset) const {
602   int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
603   return &interpreter_frame_tos_address()[index];
604 }
605 
606 #ifndef PRODUCT
607 
608 #define DESCRIBE_FP_OFFSET(name) \
609   values.describe(frame_no, fp() + frame::name##_offset, #name, 1)
610 
611 void frame::describe_pd(FrameValues& values, int frame_no) {
612   if (is_interpreted_frame()) {
613     DESCRIBE_FP_OFFSET(interpreter_frame_sender_sp);
614     DESCRIBE_FP_OFFSET(interpreter_frame_last_sp);
615     DESCRIBE_FP_OFFSET(interpreter_frame_method);
616     DESCRIBE_FP_OFFSET(interpreter_frame_mirror);
617     DESCRIBE_FP_OFFSET(interpreter_frame_mdp);
618     DESCRIBE_FP_OFFSET(interpreter_frame_cache);
619     DESCRIBE_FP_OFFSET(interpreter_frame_locals);
620     DESCRIBE_FP_OFFSET(interpreter_frame_bcp);
621     DESCRIBE_FP_OFFSET(interpreter_frame_initial_sp);
622 #ifdef AMD64
623   } else if (is_entry_frame()) {
624     // This could be more descriptive if we use the enum in
625     // stubGenerator to map to real names but it's most important to
626     // claim these frame slots so the error checking works.
627     for (int i = 0; i < entry_frame_after_call_words; i++) {
628       values.describe(frame_no, fp() - i, err_msg("call_stub word fp - %d", i));
629     }
630 #endif // AMD64
631   }
632 
633   if (is_java_frame() || Continuation::is_continuation_enterSpecial(*this)) {
634     intptr_t* ret_pc_loc;
635     intptr_t* fp_loc;
636     if (is_interpreted_frame()) {
637       ret_pc_loc = fp() + return_addr_offset;
638       fp_loc = fp();
639     } else {
640       ret_pc_loc = real_fp() - return_addr_offset;
641       fp_loc = real_fp() - sender_sp_offset;
642     }
643     address ret_pc = *(address*)ret_pc_loc;
644     values.describe(frame_no, ret_pc_loc,
645       Continuation::is_return_barrier_entry(ret_pc) ? "return address (return barrier)" : "return address");
646     values.describe(-1, fp_loc, "saved fp", 0); // "unowned" as value belongs to sender
647   }
648 }
649 
650 #endif // !PRODUCT
651 
652 intptr_t *frame::initial_deoptimization_info() {
653   // used to reset the saved FP
654   return fp();
655 }
656 
657 #ifndef PRODUCT
658 // This is a generic constructor which is only used by pns() in debug.cpp.
659 frame::frame(void* sp, void* fp, void* pc) {
660   init((intptr_t*)sp, (intptr_t*)fp, (address)pc);
661 }
662 
663 #endif
664 
665 void JavaFrameAnchor::make_walkable() {
666   // last frame set?
667   if (last_Java_sp() == nullptr) return;
668   // already walkable?
669   if (walkable()) return;
670   vmassert(last_Java_pc() == nullptr, "already walkable");
671   _last_Java_pc = (address)_last_Java_sp[-1];
672   vmassert(walkable(), "something went wrong");
673 }