1 /*
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  3  * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.
  4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  5  *
  6  * This code is free software; you can redistribute it and/or modify it
  7  * under the terms of the GNU General Public License version 2 only, as
  8  * published by the Free Software Foundation.
  9  *
 10  * This code is distributed in the hope that it will be useful, but WITHOUT
 11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 13  * version 2 for more details (a copy is included in the LICENSE file that
 14  * accompanied this code).
 15  *
 16  * You should have received a copy of the GNU General Public License version
 17  * 2 along with this work; if not, write to the Free Software Foundation,
 18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 19  *
 20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 21  * or visit www.oracle.com if you need additional information or have any
 22  * questions.
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 24  */
 25 
 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/frame.inline.hpp"
 35 #include "runtime/handles.inline.hpp"
 36 #include "runtime/javaCalls.hpp"
 37 #include "runtime/monitorChunk.hpp"
 38 #include "runtime/os.inline.hpp"
 39 #include "runtime/signature.hpp"
 40 #include "runtime/stackWatermarkSet.hpp"
 41 #include "runtime/stubCodeGenerator.hpp"
 42 #include "runtime/stubRoutines.hpp"
 43 #include "vmreg_aarch64.inline.hpp"
 44 #ifdef COMPILER1
 45 #include "c1/c1_Runtime1.hpp"
 46 #include "runtime/vframeArray.hpp"
 47 #endif
 48 
 49 #ifdef ASSERT
 50 void RegisterMap::check_location_valid() {
 51 }
 52 #endif
 53 
 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   // When we are running interpreted code the machine stack pointer, SP, is
 72   // set low enough so that the Java expression stack can grow and shrink
 73   // without ever exceeding the machine stack bounds.  So, ESP >= SP.
 74 
 75   // When we call out of an interpreted method, SP is incremented so that
 76   // the space between SP and ESP is removed.  The SP saved in the callee's
 77   // frame is the SP *before* this increment.  So, when we walk a stack of
 78   // interpreter frames the sender's SP saved in a frame might be less than
 79   // the SP at the point of call.
 80 
 81   // So unextended sp must be within the stack but we need not to check
 82   // that unextended sp >= sp
 83   if (!thread->is_in_full_stack_checked(unextended_sp)) {
 84     return false;
 85   }
 86 
 87   // an fp must be within the stack and above (but not equal) sp
 88   // second evaluation on fp+ is added to handle situation where fp is -1
 89   bool fp_safe = thread->is_in_stack_range_excl(fp, sp) &&
 90                  thread->is_in_full_stack_checked(fp + (return_addr_offset * sizeof(void*)));
 91 
 92   // We know sp/unextended_sp are safe only fp is questionable here
 93 
 94   // If the current frame is known to the code cache then we can attempt to
 95   // to construct the sender and do some validation of it. This goes a long way
 96   // toward eliminating issues when we get in frame construction code
 97 
 98   if (_cb != nullptr ) {
 99 
100     // First check if frame is complete and tester is reliable
101     // Unfortunately we can only check frame complete for runtime stubs and nmethod
102     // other generic buffer blobs are more problematic so we just assume they are
103     // ok. adapter blobs never have a frame complete and are never ok.
104 
105     if (!_cb->is_frame_complete_at(_pc)) {
106       if (_cb->is_nmethod() || _cb->is_adapter_blob() || _cb->is_runtime_stub()) {
107         return false;
108       }
109     }
110 
111     // Could just be some random pointer within the codeBlob
112     if (!_cb->code_contains(_pc)) {
113       return false;
114     }
115 
116     // Entry frame checks
117     if (is_entry_frame()) {
118       // an entry frame must have a valid fp.
119       return fp_safe && is_entry_frame_valid(thread);
120     } else if (is_upcall_stub_frame()) {
121       return fp_safe;
122     }
123 
124     intptr_t* sender_sp = nullptr;
125     intptr_t* sender_unextended_sp = nullptr;
126     address   sender_pc = nullptr;
127     intptr_t* saved_fp =  nullptr;
128 
129     if (is_interpreted_frame()) {
130       // fp must be safe
131       if (!fp_safe) {
132         return false;
133       }
134 
135       // for interpreted frames, the value below is the sender "raw" sp,
136       // which can be different from the sender unextended sp (the sp seen
137       // by the sender) because of current frame local variables
138       sender_sp = (intptr_t*) addr_at(sender_sp_offset);
139       sender_unextended_sp = (intptr_t*) this->fp()[interpreter_frame_sender_sp_offset];
140       saved_fp = (intptr_t*) this->fp()[link_offset];
141       sender_pc = pauth_strip_verifiable((address) this->fp()[return_addr_offset]);
142     } else {
143       // must be some sort of compiled/runtime frame
144       // fp does not have to be safe (although it could be check for c1?)
145 
146       // check for a valid frame_size, otherwise we are unlikely to get a valid sender_pc
147       if (_cb->frame_size() <= 0) {
148         return false;
149       }
150 
151       sender_sp = _unextended_sp + _cb->frame_size();
152       // Is sender_sp safe?
153       if (!thread->is_in_full_stack_checked((address)sender_sp)) {
154         return false;
155       }
156       sender_unextended_sp = sender_sp;
157       // Note: frame::sender_sp_offset is only valid for compiled frame
158       saved_fp = (intptr_t*) *(sender_sp - frame::sender_sp_offset);
159       // Note: PAC authentication may fail in case broken frame is passed in.
160       // Just strip it for now.
161       sender_pc = pauth_strip_pointer((address) *(sender_sp - 1));
162     }
163 
164     if (Continuation::is_return_barrier_entry(sender_pc)) {
165       // sender_pc might be invalid so check that the frame
166       // actually belongs to a Continuation.
167       if (!Continuation::is_frame_in_continuation(thread, *this)) {
168         return false;
169       }
170       // If our sender_pc is the return barrier, then our "real" sender is the continuation entry
171       frame s = Continuation::continuation_bottom_sender(thread, *this, sender_sp);
172       sender_sp = s.sp();
173       sender_pc = s.pc();
174     }
175 
176     // If the potential sender is the interpreter then we can do some more checking
177     if (Interpreter::contains(sender_pc)) {
178 
179       // fp is always saved in a recognizable place in any code we generate. However
180       // only if the sender is interpreted/call_stub (c1 too?) are we certain that the saved fp
181       // is really a frame pointer.
182 
183       if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) {
184         return false;
185       }
186 
187       // construct the potential sender
188 
189       frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
190 
191       return sender.is_interpreted_frame_valid(thread);
192 
193     }
194 
195     // We must always be able to find a recognizable pc
196     CodeBlob* sender_blob = CodeCache::find_blob(sender_pc);
197     if (sender_pc == nullptr ||  sender_blob == nullptr) {
198       return false;
199     }
200 
201     // Could just be some random pointer within the codeBlob
202     if (!sender_blob->code_contains(sender_pc)) {
203       return false;
204     }
205 
206     // We should never be able to see an adapter if the current frame is something from code cache
207     if (sender_blob->is_adapter_blob()) {
208       return false;
209     }
210 
211     // Could be the call_stub
212     if (StubRoutines::returns_to_call_stub(sender_pc)) {
213       if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) {
214         return false;
215       }
216 
217       // construct the potential sender
218 
219       frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
220 
221       // Validate the JavaCallWrapper an entry frame must have
222       address jcw = (address)sender.entry_frame_call_wrapper();
223 
224       return thread->is_in_stack_range_excl(jcw, (address)sender.fp());
225     } else if (sender_blob->is_upcall_stub()) {
226       return false;
227     }
228 
229     nmethod* nm = sender_blob->as_nmethod_or_null();
230     if (nm != nullptr) {
231       if (nm->is_deopt_entry(sender_pc) || nm->method()->is_method_handle_intrinsic()) {
232         return false;
233       }
234     }
235 
236     // If the frame size is 0 something (or less) is bad because every nmethod has a non-zero frame size
237     // because the return address counts against the callee's frame.
238 
239     if (sender_blob->frame_size() <= 0) {
240       assert(!sender_blob->is_nmethod(), "should count return address at least");
241       return false;
242     }
243 
244     // We should never be able to see anything here except an nmethod. If something in the
245     // code cache (current frame) is called by an entity within the code cache that entity
246     // should not be anything but the call stub (already covered), the interpreter (already covered)
247     // or an nmethod.
248 
249     if (!sender_blob->is_nmethod()) {
250         return false;
251     }
252 
253     // Could put some more validation for the potential non-interpreted sender
254     // frame we'd create by calling sender if I could think of any. Wait for next crash in forte...
255 
256     // One idea is seeing if the sender_pc we have is one that we'd expect to call to current cb
257 
258     // We've validated the potential sender that would be created
259     return true;
260   }
261 
262   // Must be native-compiled frame. Since sender will try and use fp to find
263   // linkages it must be safe
264 
265   if (!fp_safe) {
266     return false;
267   }
268 
269   // Will the pc we fetch be non-zero (which we'll find at the oldest frame)
270 
271   if ( (address) this->fp()[return_addr_offset] == nullptr) return false;
272 
273 
274   // could try and do some more potential verification of native frame if we could think of some...
275 
276   return true;
277 
278 }
279 
280 void frame::patch_pc(Thread* thread, address pc) {
281   assert(_cb == CodeCache::find_blob(pc), "unexpected pc");
282   address* pc_addr = &(((address*) sp())[-1]);
283   address signed_pc = pauth_sign_return_address(pc);
284   address pc_old = pauth_strip_verifiable(*pc_addr);
285 
286   if (TracePcPatching) {
287     tty->print("patch_pc at address " INTPTR_FORMAT " [" INTPTR_FORMAT " -> " INTPTR_FORMAT "]",
288                   p2i(pc_addr), p2i(pc_old), p2i(pc));
289     if (VM_Version::use_rop_protection()) {
290       tty->print(" [signed " INTPTR_FORMAT " -> " INTPTR_FORMAT "]", p2i(*pc_addr), p2i(signed_pc));
291     }
292     tty->print_cr("");
293   }
294 
295   assert(!Continuation::is_return_barrier_entry(pc_old), "return barrier");
296 
297   // Either the return address is the original one or we are going to
298   // patch in the same address that's already there.
299   assert(_pc == pc_old || pc == pc_old || pc_old == nullptr, "");
300   DEBUG_ONLY(address old_pc = _pc;)
301   *pc_addr = signed_pc;
302   _pc = pc; // must be set before call to get_deopt_original_pc
303   address original_pc = get_deopt_original_pc();
304   if (original_pc != nullptr) {
305     assert(original_pc == old_pc, "expected original PC to be stored before patching");
306     _deopt_state = is_deoptimized;
307     _pc = original_pc;
308   } else {
309     _deopt_state = not_deoptimized;
310   }
311 }
312 
313 intptr_t* frame::entry_frame_argument_at(int offset) const {
314   // convert offset to index to deal with tsi
315   int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
316   // Entry frame's arguments are always in relation to unextended_sp()
317   return &unextended_sp()[index];
318 }
319 
320 // locals
321 
322 void frame::interpreter_frame_set_locals(intptr_t* locs)  {
323   assert(is_interpreted_frame(), "interpreted frame expected");
324   // set relativized locals
325   ptr_at_put(interpreter_frame_locals_offset, (intptr_t) (locs - fp()));
326 }
327 
328 // sender_sp
329 
330 intptr_t* frame::interpreter_frame_sender_sp() const {
331   assert(is_interpreted_frame(), "interpreted frame expected");
332   return (intptr_t*) at(interpreter_frame_sender_sp_offset);
333 }
334 
335 void frame::set_interpreter_frame_sender_sp(intptr_t* sender_sp) {
336   assert(is_interpreted_frame(), "interpreted frame expected");
337   ptr_at_put(interpreter_frame_sender_sp_offset, (intptr_t) sender_sp);
338 }
339 
340 
341 // monitor elements
342 
343 BasicObjectLock* frame::interpreter_frame_monitor_begin() const {
344   return (BasicObjectLock*) addr_at(interpreter_frame_monitor_block_bottom_offset);
345 }
346 
347 BasicObjectLock* frame::interpreter_frame_monitor_end() const {
348   BasicObjectLock* result = (BasicObjectLock*) at_relative(interpreter_frame_monitor_block_top_offset);
349   // make sure the pointer points inside the frame
350   assert(sp() <= (intptr_t*) result, "monitor end should be above the stack pointer");
351   assert((intptr_t*) result < fp(),  "monitor end should be strictly below the frame pointer");
352   return result;
353 }
354 
355 void frame::interpreter_frame_set_monitor_end(BasicObjectLock* value) {
356   assert(is_interpreted_frame(), "interpreted frame expected");
357   // set relativized monitor_block_top
358   ptr_at_put(interpreter_frame_monitor_block_top_offset, (intptr_t*)value - fp());
359   assert(at_absolute(interpreter_frame_monitor_block_top_offset) <= interpreter_frame_monitor_block_top_offset, "");
360 }
361 
362 // Used by template based interpreter deoptimization
363 void frame::interpreter_frame_set_last_sp(intptr_t* sp) {
364   assert(is_interpreted_frame(), "interpreted frame expected");
365   // set relativized last_sp
366   ptr_at_put(interpreter_frame_last_sp_offset, sp != nullptr ? (sp - fp()) : 0);
367 }
368 
369 // Used by template based interpreter deoptimization
370 void frame::interpreter_frame_set_extended_sp(intptr_t* sp) {
371   assert(is_interpreted_frame(), "interpreted frame expected");
372   // set relativized extended_sp
373   ptr_at_put(interpreter_frame_extended_sp_offset, (sp - fp()));
374 }
375 
376 frame frame::sender_for_entry_frame(RegisterMap* map) const {
377   assert(map != nullptr, "map must be set");
378   // Java frame called from C; skip all C frames and return top C
379   // frame of that chunk as the sender
380   JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
381   assert(!entry_frame_is_first(), "next Java fp must be non zero");
382   assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
383   // Since we are walking the stack now this nested anchor is obviously walkable
384   // even if it wasn't when it was stacked.
385   jfa->make_walkable();
386   map->clear();
387   assert(map->include_argument_oops(), "should be set by clear");
388   frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
389   fr.set_sp_is_trusted();
390 
391   return fr;
392 }
393 
394 UpcallStub::FrameData* UpcallStub::frame_data_for_frame(const frame& frame) const {
395   assert(frame.is_upcall_stub_frame(), "wrong frame");
396   // need unextended_sp here, since normal sp is wrong for interpreter callees
397   return reinterpret_cast<UpcallStub::FrameData*>(
398     reinterpret_cast<address>(frame.unextended_sp()) + in_bytes(_frame_data_offset));
399 }
400 
401 bool frame::upcall_stub_frame_is_first() const {
402   assert(is_upcall_stub_frame(), "must be optimzed entry frame");
403   UpcallStub* blob = _cb->as_upcall_stub();
404   JavaFrameAnchor* jfa = blob->jfa_for_frame(*this);
405   return jfa->last_Java_sp() == nullptr;
406 }
407 
408 frame frame::sender_for_upcall_stub_frame(RegisterMap* map) const {
409   assert(map != nullptr, "map must be set");
410   UpcallStub* blob = _cb->as_upcall_stub();
411   // Java frame called from C; skip all C frames and return top C
412   // frame of that chunk as the sender
413   JavaFrameAnchor* jfa = blob->jfa_for_frame(*this);
414   assert(!upcall_stub_frame_is_first(), "must have a frame anchor to go back to");
415   assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
416   // Since we are walking the stack now this nested anchor is obviously walkable
417   // even if it wasn't when it was stacked.
418   jfa->make_walkable();
419   map->clear();
420   assert(map->include_argument_oops(), "should be set by clear");
421   frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
422 
423   return fr;
424 }
425 
426 #if defined(ASSERT)
427 static address get_register_address_in_stub(const frame& stub_fr, VMReg reg) {
428   RegisterMap map(nullptr,
429                   RegisterMap::UpdateMap::include,
430                   RegisterMap::ProcessFrames::skip,
431                   RegisterMap::WalkContinuation::skip);
432   stub_fr.oop_map()->update_register_map(&stub_fr, &map);
433   return map.location(reg, stub_fr.sp());
434 }
435 #endif
436 
437 JavaThread** frame::saved_thread_address(const frame& f) {
438   CodeBlob* cb = f.cb();
439   assert(cb != nullptr && cb->is_runtime_stub(), "invalid frame");
440 
441   JavaThread** thread_addr;
442 #ifdef COMPILER1
443   if (cb == Runtime1::blob_for(StubId::c1_monitorenter_id) ||
444       cb == Runtime1::blob_for(StubId::c1_monitorenter_nofpu_id)) {
445     thread_addr = (JavaThread**)(f.sp() + Runtime1::runtime_blob_current_thread_offset(f));
446   } else
447 #endif
448   {
449     // c2 only saves rbp in the stub frame so nothing to do.
450     thread_addr = nullptr;
451   }
452   assert(get_register_address_in_stub(f, SharedRuntime::thread_register()) == (address)thread_addr, "wrong thread address");
453   return thread_addr;
454 }
455 
456 //------------------------------------------------------------------------------
457 // frame::sender_for_interpreter_frame
458 frame frame::sender_for_interpreter_frame(RegisterMap* map) const {
459   // SP is the raw SP from the sender after adapter or interpreter
460   // extension.
461   intptr_t* sender_sp = this->sender_sp();
462 
463   // This is the sp before any possible extension (adapter/locals).
464   intptr_t* unextended_sp = interpreter_frame_sender_sp();
465   intptr_t* sender_fp = link();
466 
467 #if defined(COMPILER1) || COMPILER2_OR_JVMCI
468   if (map->update_map()) {
469     update_map_with_saved_link(map, (intptr_t**) addr_at(link_offset));
470   }
471 #endif // defined(COMPILER1) || COMPILER1_OR_COMPILER2
472 
473   // For ROP protection, Interpreter will have signed the sender_pc,
474   // but there is no requirement to authenticate it here.
475   address sender_pc = pauth_strip_verifiable(sender_pc_maybe_signed());
476 
477   if (Continuation::is_return_barrier_entry(sender_pc)) {
478     if (map->walk_cont()) { // about to walk into an h-stack
479       return Continuation::top_frame(*this, map);
480     } else {
481       return Continuation::continuation_bottom_sender(map->thread(), *this, sender_sp);
482     }
483   }
484 
485   return frame(sender_sp, unextended_sp, sender_fp, sender_pc);
486 }
487 
488 bool frame::is_interpreted_frame_valid(JavaThread* thread) const {
489   assert(is_interpreted_frame(), "Not an interpreted frame");
490   // These are reasonable sanity checks
491   if (fp() == nullptr || (intptr_t(fp()) & (wordSize-1)) != 0) {
492     return false;
493   }
494   if (sp() == nullptr || (intptr_t(sp()) & (wordSize-1)) != 0) {
495     return false;
496   }
497   if (fp() + interpreter_frame_initial_sp_offset < sp()) {
498     return false;
499   }
500   // These are hacks to keep us out of trouble.
501   // The problem with these is that they mask other problems
502   if (fp() <= sp()) {        // this attempts to deal with unsigned comparison above
503     return false;
504   }
505 
506   // do some validation of frame elements
507 
508   // first the method
509 
510   Method* m = safe_interpreter_frame_method();
511 
512   // validate the method we'd find in this potential sender
513   if (!Method::is_valid_method(m)) return false;
514 
515   // stack frames shouldn't be much larger than max_stack elements
516   // this test requires the use of unextended_sp which is the sp as seen by
517   // the current frame, and not sp which is the "raw" pc which could point
518   // further because of local variables of the callee method inserted after
519   // method arguments
520   if (fp() - unextended_sp() > 1024 + m->max_stack()*Interpreter::stackElementSize) {
521     return false;
522   }
523 
524   // validate bci/bcx
525 
526   address  bcp    = interpreter_frame_bcp();
527   if (m->validate_bci_from_bcp(bcp) < 0) {
528     return false;
529   }
530 
531   // validate constantPoolCache*
532   ConstantPoolCache* cp = *interpreter_frame_cache_addr();
533   if (MetaspaceObj::is_valid(cp) == false) return false;
534 
535   // validate locals
536 
537   address locals =  (address)interpreter_frame_locals();
538   return thread->is_in_stack_range_incl(locals, (address)fp());
539 }
540 
541 BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
542   assert(is_interpreted_frame(), "interpreted frame expected");
543   Method* method = interpreter_frame_method();
544   BasicType type = method->result_type();
545 
546   intptr_t* tos_addr;
547   if (method->is_native()) {
548     // TODO : ensure AARCH64 does the same as Intel here i.e. push v0 then r0
549     // Prior to calling into the runtime to report the method_exit the possible
550     // return value is pushed to the native stack. If the result is a jfloat/jdouble
551     // then ST0 is saved before EAX/EDX. See the note in generate_native_result
552     tos_addr = (intptr_t*)sp();
553     if (type == T_FLOAT || type == T_DOUBLE) {
554       // This is times two because we do a push(ltos) after pushing XMM0
555       // and that takes two interpreter stack slots.
556       tos_addr += 2 * Interpreter::stackElementWords;
557     }
558   } else {
559     tos_addr = (intptr_t*)interpreter_frame_tos_address();
560   }
561 
562   switch (type) {
563     case T_OBJECT  :
564     case T_ARRAY   : {
565       oop obj;
566       if (method->is_native()) {
567         obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
568       } else {
569         oop* obj_p = (oop*)tos_addr;
570         obj = (obj_p == nullptr) ? (oop)nullptr : *obj_p;
571       }
572       assert(Universe::is_in_heap_or_null(obj), "sanity check");
573       *oop_result = obj;
574       break;
575     }
576     case T_BOOLEAN : value_result->z = *(jboolean*)tos_addr; break;
577     case T_BYTE    : value_result->b = *(jbyte*)tos_addr; break;
578     case T_CHAR    : value_result->c = *(jchar*)tos_addr; break;
579     case T_SHORT   : value_result->s = *(jshort*)tos_addr; break;
580     case T_INT     : value_result->i = *(jint*)tos_addr; break;
581     case T_LONG    : value_result->j = *(jlong*)tos_addr; break;
582     case T_FLOAT   : {
583         value_result->f = *(jfloat*)tos_addr;
584       break;
585     }
586     case T_DOUBLE  : value_result->d = *(jdouble*)tos_addr; break;
587     case T_VOID    : /* Nothing to do */ break;
588     default        : ShouldNotReachHere();
589   }
590 
591   return type;
592 }
593 
594 intptr_t* frame::interpreter_frame_tos_at(jint offset) const {
595   int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
596   return &interpreter_frame_tos_address()[index];
597 }
598 
599 #ifndef PRODUCT
600 
601 #define DESCRIBE_FP_OFFSET(name) \
602   values.describe(frame_no, fp() + frame::name##_offset, #name)
603 
604 void frame::describe_pd(FrameValues& values, int frame_no) {
605   if (is_interpreted_frame()) {
606     DESCRIBE_FP_OFFSET(interpreter_frame_sender_sp);
607     DESCRIBE_FP_OFFSET(interpreter_frame_last_sp);
608     DESCRIBE_FP_OFFSET(interpreter_frame_method);
609     DESCRIBE_FP_OFFSET(interpreter_frame_mdp);
610     DESCRIBE_FP_OFFSET(interpreter_frame_extended_sp);
611     DESCRIBE_FP_OFFSET(interpreter_frame_mirror);
612     DESCRIBE_FP_OFFSET(interpreter_frame_cache);
613     DESCRIBE_FP_OFFSET(interpreter_frame_locals);
614     DESCRIBE_FP_OFFSET(interpreter_frame_bcp);
615     DESCRIBE_FP_OFFSET(interpreter_frame_initial_sp);
616   }
617 
618   if (is_java_frame() || Continuation::is_continuation_enterSpecial(*this)) {
619     intptr_t* ret_pc_loc;
620     intptr_t* fp_loc;
621     if (is_interpreted_frame()) {
622       ret_pc_loc = fp() + return_addr_offset;
623       fp_loc = fp();
624     } else {
625       ret_pc_loc = real_fp() - return_addr_offset;
626       fp_loc = real_fp() - sender_sp_offset;
627     }
628     address ret_pc = *(address*)ret_pc_loc;
629     values.describe(frame_no, ret_pc_loc,
630       Continuation::is_return_barrier_entry(ret_pc) ? "return address (return barrier)" : "return address");
631     values.describe(-1, fp_loc, "saved fp", 0); // "unowned" as value belongs to sender
632   }
633 }
634 #endif
635 
636 intptr_t *frame::initial_deoptimization_info() {
637   // Not used on aarch64, but we must return something.
638   return nullptr;
639 }
640 
641 #undef DESCRIBE_FP_OFFSET
642 
643 #define DESCRIBE_FP_OFFSET(name)                     \
644   {                                                  \
645     uintptr_t *p = (uintptr_t *)fp;                  \
646     printf(INTPTR_FORMAT " " INTPTR_FORMAT " %s\n",  \
647            (uintptr_t)(p + frame::name##_offset),    \
648            p[frame::name##_offset], #name);          \
649   }
650 
651 static THREAD_LOCAL uintptr_t nextfp;
652 static THREAD_LOCAL uintptr_t nextpc;
653 static THREAD_LOCAL uintptr_t nextsp;
654 static THREAD_LOCAL RegisterMap *reg_map;
655 
656 static void printbc(Method *m, intptr_t bcx) {
657   const char *name;
658   char buf[16];
659   if (m->validate_bci_from_bcp((address)bcx) < 0
660       || !m->contains((address)bcx)) {
661     name = "???";
662     os::snprintf_checked(buf, sizeof buf, "(bad)");
663   } else {
664     int bci = m->bci_from((address)bcx);
665     os::snprintf_checked(buf, sizeof buf, "%d", bci);
666     name = Bytecodes::name(m->code_at(bci));
667   }
668   ResourceMark rm;
669   printf("%s : %s ==> %s\n", m->name_and_sig_as_C_string(), buf, name);
670 }
671 
672 static void internal_pf(uintptr_t sp, uintptr_t fp, uintptr_t pc, uintptr_t bcx) {
673   if (! fp)
674     return;
675 
676   DESCRIBE_FP_OFFSET(return_addr);
677   DESCRIBE_FP_OFFSET(link);
678   DESCRIBE_FP_OFFSET(interpreter_frame_sender_sp);
679   DESCRIBE_FP_OFFSET(interpreter_frame_last_sp);
680   DESCRIBE_FP_OFFSET(interpreter_frame_method);
681   DESCRIBE_FP_OFFSET(interpreter_frame_mdp);
682   DESCRIBE_FP_OFFSET(interpreter_frame_extended_sp);
683   DESCRIBE_FP_OFFSET(interpreter_frame_mirror);
684   DESCRIBE_FP_OFFSET(interpreter_frame_cache);
685   DESCRIBE_FP_OFFSET(interpreter_frame_locals);
686   DESCRIBE_FP_OFFSET(interpreter_frame_bcp);
687   DESCRIBE_FP_OFFSET(interpreter_frame_initial_sp);
688   uintptr_t *p = (uintptr_t *)fp;
689 
690   // We want to see all frames, native and Java.  For compiled and
691   // interpreted frames we have special information that allows us to
692   // unwind them; for everything else we assume that the native frame
693   // pointer chain is intact.
694   frame this_frame((intptr_t*)sp, (intptr_t*)fp, (address)pc);
695   if (this_frame.is_compiled_frame() ||
696       this_frame.is_interpreted_frame()) {
697     frame sender = this_frame.sender(reg_map);
698     nextfp = (uintptr_t)sender.fp();
699     nextpc = (uintptr_t)sender.pc();
700     nextsp = (uintptr_t)sender.unextended_sp();
701   } else {
702     nextfp = p[frame::link_offset];
703     nextpc = p[frame::return_addr_offset];
704     nextsp = (uintptr_t)&p[frame::sender_sp_offset];
705   }
706 
707   if (bcx == -1ULL)
708     bcx = p[frame::interpreter_frame_bcp_offset];
709 
710   if (Interpreter::contains((address)pc)) {
711     Method* m = (Method*)p[frame::interpreter_frame_method_offset];
712     if(m && m->is_method()) {
713       printbc(m, bcx);
714     } else
715       printf("not a Method\n");
716   } else {
717     CodeBlob *cb = CodeCache::find_blob((address)pc);
718     if (cb != nullptr) {
719       if (cb->is_nmethod()) {
720         ResourceMark rm;
721         nmethod* nm = (nmethod*)cb;
722         printf("nmethod %s\n", nm->method()->name_and_sig_as_C_string());
723       } else if (cb->name()) {
724         printf("CodeBlob %s\n", cb->name());
725       }
726     }
727   }
728 }
729 
730 extern "C" void npf() {
731   CodeBlob *cb = CodeCache::find_blob((address)nextpc);
732   // C2 does not always chain the frame pointers when it can, instead
733   // preferring to use fixed offsets from SP, so a simple leave() does
734   // not work.  Instead, it adds the frame size to SP then pops FP and
735   // LR.  We have to do the same thing to get a good call chain.
736   if (cb && cb->frame_size())
737     nextfp = nextsp + wordSize * (cb->frame_size() - 2);
738   internal_pf (nextsp, nextfp, nextpc, -1);
739 }
740 
741 extern "C" void pf(uintptr_t sp, uintptr_t fp, uintptr_t pc,
742                    uintptr_t bcx, uintptr_t thread) {
743   if (!reg_map) {
744     reg_map = NEW_C_HEAP_OBJ(RegisterMap, mtInternal);
745     ::new (reg_map) RegisterMap(reinterpret_cast<JavaThread*>(thread),
746                                 RegisterMap::UpdateMap::skip,
747                                 RegisterMap::ProcessFrames::include,
748                                 RegisterMap::WalkContinuation::skip);
749   } else {
750     *reg_map = RegisterMap(reinterpret_cast<JavaThread*>(thread),
751                            RegisterMap::UpdateMap::skip,
752                            RegisterMap::ProcessFrames::include,
753                            RegisterMap::WalkContinuation::skip);
754   }
755 
756   {
757     CodeBlob *cb = CodeCache::find_blob((address)pc);
758     if (cb && cb->frame_size())
759       fp = sp + wordSize * (cb->frame_size() - 2);
760   }
761   internal_pf(sp, fp, pc, bcx);
762 }
763 
764 // support for printing out where we are in a Java method
765 // needs to be passed current fp and bcp register values
766 // prints method name, bc index and bytecode name
767 extern "C" void pm(uintptr_t fp, uintptr_t bcx) {
768   DESCRIBE_FP_OFFSET(interpreter_frame_method);
769   uintptr_t *p = (uintptr_t *)fp;
770   Method* m = (Method*)p[frame::interpreter_frame_method_offset];
771   printbc(m, bcx);
772 }
773 
774 #ifndef PRODUCT
775 // This is a generic constructor which is only used by pns() in debug.cpp.
776 frame::frame(void* sp, void* fp, void* pc) {
777   init((intptr_t*)sp, (intptr_t*)fp, (address)pc);
778 }
779 
780 #endif
781 
782 void JavaFrameAnchor::make_walkable() {
783   // last frame set?
784   if (last_Java_sp() == nullptr) return;
785   // already walkable?
786   if (walkable()) return;
787   vmassert(last_Java_sp() != nullptr, "not called from Java code?");
788   _last_Java_pc = (address)_last_Java_sp[-1];
789   vmassert(walkable(), "something went wrong");
790 }