1 /*
2 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.
4 * Copyright (c) 2020, 2023, Huawei Technologies Co., Ltd. All rights reserved.
5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 *
7 * This code is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 only, as
9 * published by the Free Software Foundation.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 *
25 */
26
27 #include "compiler/oopMap.hpp"
28 #include "interpreter/interpreter.hpp"
29 #include "memory/resourceArea.hpp"
30 #include "memory/universe.hpp"
31 #include "oops/markWord.hpp"
32 #include "oops/method.hpp"
33 #include "oops/oop.inline.hpp"
34 #include "prims/methodHandles.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/os.inline.hpp"
40 #include "runtime/signature.hpp"
41 #include "runtime/stackWatermarkSet.hpp"
42 #include "runtime/stubCodeGenerator.hpp"
43 #include "runtime/stubRoutines.hpp"
44 #include "vmreg_riscv.inline.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
56 // Profiling/safepoint support
57
58 bool frame::safe_for_sender(JavaThread *thread) {
59 address addr_sp = (address)_sp;
60 address addr_fp = (address)_fp;
61 address unextended_sp = (address)_unextended_sp;
62
63 // consider stack guards when trying to determine "safe" stack pointers
64 // sp must be within the usable part of the stack (not in guards)
65 if (!thread->is_in_usable_stack(addr_sp)) {
66 return false;
67 }
68
69 // When we are running interpreted code the machine stack pointer, SP, is
70 // set low enough so that the Java expression stack can grow and shrink
71 // without ever exceeding the machine stack bounds. So, ESP >= SP.
72
73 // When we call out of an interpreted method, SP is incremented so that
74 // the space between SP and ESP is removed. The SP saved in the callee's
75 // frame is the SP *before* this increment. So, when we walk a stack of
76 // interpreter frames the sender's SP saved in a frame might be less than
77 // the SP at the point of call.
78
79 // So unextended sp must be within the stack but we need not to check
80 // that unextended sp >= sp
81
82 if (!thread->is_in_full_stack_checked(unextended_sp)) {
83 return false;
84 }
85
86 // an fp must be within the stack and above (but not equal) sp
87 // second evaluation on fp+ is added to handle situation where fp is -1
88 bool fp_safe = thread->is_in_stack_range_excl(addr_fp, addr_sp) &&
89 thread->is_in_full_stack_checked(addr_fp + (return_addr_offset * sizeof(void*)));
90
91 // We know sp/unextended_sp are safe only fp is questionable here
92
93 // If the current frame is known to the code cache then we can attempt to
94 // to construct the sender and do some validation of it. This goes a long way
95 // toward eliminating issues when we get in frame construction code
96
97 if (_cb != nullptr) {
98
99 // First check if frame is complete and tester is reliable
100 // Unfortunately we can only check frame complete for runtime stubs and nmethod
101 // other generic buffer blobs are more problematic so we just assume they are
102 // ok. adapter blobs never have a frame complete and are never ok.
103
104 if (!_cb->is_frame_complete_at(_pc)) {
105 if (_cb->is_nmethod() || _cb->is_adapter_blob() || _cb->is_runtime_stub()) {
106 return false;
107 }
108 }
109
110 // Could just be some random pointer within the codeBlob
111 if (!_cb->code_contains(_pc)) {
112 return false;
113 }
114
115 // Entry frame checks
116 if (is_entry_frame()) {
117 // an entry frame must have a valid fp.
118 return fp_safe && is_entry_frame_valid(thread);
119 }
120
121 intptr_t* sender_sp = nullptr;
122 intptr_t* sender_unextended_sp = nullptr;
123 address sender_pc = nullptr;
124 intptr_t* saved_fp = nullptr;
125
126 if (is_interpreted_frame()) {
127 // fp must be safe
128 if (!fp_safe) {
129 return false;
130 }
131
132 sender_pc = (address)this->fp()[return_addr_offset];
133 // for interpreted frames, the value below is the sender "raw" sp,
134 // which can be different from the sender unextended sp (the sp seen
135 // by the sender) because of current frame local variables
136 sender_sp = (intptr_t*) addr_at(sender_sp_offset);
137 sender_unextended_sp = (intptr_t*) this->fp()[interpreter_frame_sender_sp_offset];
138 saved_fp = (intptr_t*) this->fp()[link_offset];
139 } else {
140 // must be some sort of compiled/runtime frame
141 // fp does not have to be safe (although it could be check for c1?)
142
143 // check for a valid frame_size, otherwise we are unlikely to get a valid sender_pc
144 if (_cb->frame_size() <= 0) {
145 return false;
146 }
147
148 sender_sp = _unextended_sp + _cb->frame_size();
149 // Is sender_sp safe?
150 if (!thread->is_in_full_stack_checked((address)sender_sp)) {
151 return false;
152 }
153
154 sender_unextended_sp = sender_sp;
155 sender_pc = (address) *(sender_sp - 1);
156 saved_fp = (intptr_t*) *(sender_sp - 2);
157 }
158
159 if (Continuation::is_return_barrier_entry(sender_pc)) {
160 // sender_pc might be invalid so check that the frame
161 // actually belongs to a Continuation.
162 if (!Continuation::is_frame_in_continuation(thread, *this)) {
163 return false;
164 }
165 // If our sender_pc is the return barrier, then our "real" sender is the continuation entry
166 frame s = Continuation::continuation_bottom_sender(thread, *this, sender_sp);
167 sender_sp = s.sp();
168 sender_pc = s.pc();
169 }
170
171 // If the potential sender is the interpreter then we can do some more checking
172 if (Interpreter::contains(sender_pc)) {
173
174 // fp is always saved in a recognizable place in any code we generate. However
175 // only if the sender is interpreted/call_stub (c1 too?) are we certain that the saved fp
176 // is really a frame pointer.
177 if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) {
178 return false;
179 }
180
181 // construct the potential sender
182 frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
183
184 return sender.is_interpreted_frame_valid(thread);
185 }
186
187 // We must always be able to find a recognizable pc
188 CodeBlob* sender_blob = CodeCache::find_blob(sender_pc);
189 if (sender_pc == nullptr || sender_blob == nullptr) {
190 return false;
191 }
192
193 // Could just be some random pointer within the codeBlob
194 if (!sender_blob->code_contains(sender_pc)) {
195 return false;
196 }
197
198 // We should never be able to see an adapter if the current frame is something from code cache
199 if (sender_blob->is_adapter_blob()) {
200 return false;
201 }
202
203 // Could be the call_stub
204 if (StubRoutines::returns_to_call_stub(sender_pc)) {
205 if (!thread->is_in_stack_range_excl((address)saved_fp, (address)sender_sp)) {
206 return false;
207 }
208
209 // construct the potential sender
210 frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);
211
212 // Validate the JavaCallWrapper an entry frame must have
213 address jcw = (address)sender.entry_frame_call_wrapper();
214
215 return thread->is_in_stack_range_excl(jcw, (address)sender.fp());
216 }
217
218 nmethod* nm = sender_blob->as_nmethod_or_null();
219 if (nm != nullptr) {
220 if (nm->is_deopt_entry(sender_pc) || nm->method()->is_method_handle_intrinsic()) {
221 return false;
222 }
223 }
224
225 // If the frame size is 0 something (or less) is bad because every nmethod has a non-zero frame size
226 // because the return address counts against the callee's frame.
227 if (sender_blob->frame_size() <= 0) {
228 assert(!sender_blob->is_nmethod(), "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 if (!sender_blob->is_nmethod()) {
237 return false;
238 }
239
240 // Could put some more validation for the potential non-interpreted sender
241 // frame we'd create by calling sender if I could think of any. Wait for next crash in forte...
242
243 // One idea is seeing if the sender_pc we have is one that we'd expect to call to current cb
244
245 // We've validated the potential sender that would be created
246 return true;
247 }
248
249 // Must be native-compiled frame. Since sender will try and use fp to find
250 // linkages it must be safe
251 if (!fp_safe) {
252 return false;
253 }
254
255 // Will the pc we fetch be non-zero (which we'll find at the oldest frame)
256 if ((address)this->fp()[return_addr_offset] == nullptr) { return false; }
257
258 return true;
259 }
260
261 void frame::patch_pc(Thread* thread, address pc) {
262 assert(_cb == CodeCache::find_blob(pc), "unexpected pc");
263 address* pc_addr = &(((address*) sp())[-1]);
264 address pc_old = *pc_addr;
265
266 if (TracePcPatching) {
267 tty->print_cr("patch_pc at address " INTPTR_FORMAT " [" INTPTR_FORMAT " -> " INTPTR_FORMAT "]",
268 p2i(pc_addr), p2i(pc_old), p2i(pc));
269 }
270
271 assert(!Continuation::is_return_barrier_entry(pc_old), "return barrier");
272
273 // Either the return address is the original one or we are going to
274 // patch in the same address that's already there.
275 assert(_pc == pc_old || pc == pc_old || pc_old == nullptr, "must be");
276 DEBUG_ONLY(address old_pc = _pc;)
277 *pc_addr = pc;
278 _pc = pc; // must be set before call to get_deopt_original_pc
279 address original_pc = get_deopt_original_pc();
280 if (original_pc != nullptr) {
281 assert(original_pc == old_pc, "expected original PC to be stored before patching");
282 _deopt_state = is_deoptimized;
283 _pc = original_pc;
284 } else {
285 _deopt_state = not_deoptimized;
286 }
287 }
288
289 intptr_t* frame::entry_frame_argument_at(int offset) const {
290 // convert offset to index to deal with tsi
291 int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
292 // Entry frame's arguments are always in relation to unextended_sp()
293 return &unextended_sp()[index];
294 }
295
296 // locals
297
298 void frame::interpreter_frame_set_locals(intptr_t* locs) {
299 assert(is_interpreted_frame(), "interpreted frame expected");
300 // set relativized locals
301 ptr_at_put(interpreter_frame_locals_offset, (intptr_t) (locs - fp()));
302 }
303
304 // sender_sp
305
306 intptr_t* frame::interpreter_frame_sender_sp() const {
307 assert(is_interpreted_frame(), "interpreted frame expected");
308 return (intptr_t*) at(interpreter_frame_sender_sp_offset);
309 }
310
311 void frame::set_interpreter_frame_sender_sp(intptr_t* sender_sp) {
312 assert(is_interpreted_frame(), "interpreted frame expected");
313 ptr_at_put(interpreter_frame_sender_sp_offset, (intptr_t) sender_sp);
314 }
315
316
317 // monitor elements
318
319 BasicObjectLock* frame::interpreter_frame_monitor_begin() const {
320 return (BasicObjectLock*) addr_at(interpreter_frame_monitor_block_bottom_offset);
321 }
322
323 BasicObjectLock* frame::interpreter_frame_monitor_end() const {
324 BasicObjectLock* result = (BasicObjectLock*) at_relative(interpreter_frame_monitor_block_top_offset);
325 // make sure the pointer points inside the frame
326 assert(sp() <= (intptr_t*) result, "monitor end should be above the stack pointer");
327 assert((intptr_t*) result < fp(), "monitor end should be strictly below the frame pointer");
328 return result;
329 }
330
331 void frame::interpreter_frame_set_monitor_end(BasicObjectLock* value) {
332 assert(is_interpreted_frame(), "interpreted frame expected");
333 // set relativized monitor_block_top
334 ptr_at_put(interpreter_frame_monitor_block_top_offset, (intptr_t*)value - fp());
335 assert(at_absolute(interpreter_frame_monitor_block_top_offset) <= interpreter_frame_monitor_block_top_offset, "");
336 }
337
338 // Used by template based interpreter deoptimization
339 void frame::interpreter_frame_set_last_sp(intptr_t* last_sp) {
340 assert(is_interpreted_frame(), "interpreted frame expected");
341 // set relativized last_sp
342 ptr_at_put(interpreter_frame_last_sp_offset, last_sp != nullptr ? (last_sp - fp()) : 0);
343 }
344
345 void frame::interpreter_frame_set_extended_sp(intptr_t* sp) {
346 assert(is_interpreted_frame(), "interpreted frame expected");
347 // set relativized extended_sp
348 ptr_at_put(interpreter_frame_extended_sp_offset, (sp - fp()));
349 }
350
351 frame frame::sender_for_entry_frame(RegisterMap* map) const {
352 assert(map != nullptr, "map must be set");
353 // Java frame called from C; skip all C frames and return top C
354 // frame of that chunk as the sender
355 JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();
356 assert(!entry_frame_is_first(), "next Java fp must be non zero");
357 assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
358 // Since we are walking the stack now this nested anchor is obviously walkable
359 // even if it wasn't when it was stacked.
360 jfa->make_walkable();
361 map->clear();
362 assert(map->include_argument_oops(), "should be set by clear");
363 frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
364 return fr;
365 }
366
367 UpcallStub::FrameData* UpcallStub::frame_data_for_frame(const frame& frame) const {
368 assert(frame.is_upcall_stub_frame(), "wrong frame");
369 // need unextended_sp here, since normal sp is wrong for interpreter callees
370 return reinterpret_cast<UpcallStub::FrameData*>(
371 reinterpret_cast<address>(frame.unextended_sp()) + in_bytes(_frame_data_offset));
372 }
373
374 bool frame::upcall_stub_frame_is_first() const {
375 assert(is_upcall_stub_frame(), "must be optimzed entry frame");
376 UpcallStub* blob = _cb->as_upcall_stub();
377 JavaFrameAnchor* jfa = blob->jfa_for_frame(*this);
378 return jfa->last_Java_sp() == nullptr;
379 }
380
381 frame frame::sender_for_upcall_stub_frame(RegisterMap* map) const {
382 assert(map != nullptr, "map must be set");
383 UpcallStub* blob = _cb->as_upcall_stub();
384 // Java frame called from C; skip all C frames and return top C
385 // frame of that chunk as the sender
386 JavaFrameAnchor* jfa = blob->jfa_for_frame(*this);
387 assert(!upcall_stub_frame_is_first(), "must have a frame anchor to go back to");
388 assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");
389 // Since we are walking the stack now this nested anchor is obviously walkable
390 // even if it wasn't when it was stacked.
391 jfa->make_walkable();
392 map->clear();
393 assert(map->include_argument_oops(), "should be set by clear");
394 frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());
395
396 return fr;
397 }
398
399 #if defined(ASSERT)
400 static address get_register_address_in_stub(const frame& stub_fr, VMReg reg) {
401 RegisterMap map(nullptr,
402 RegisterMap::UpdateMap::include,
403 RegisterMap::ProcessFrames::skip,
404 RegisterMap::WalkContinuation::skip);
405 stub_fr.oop_map()->update_register_map(&stub_fr, &map);
406 return map.location(reg, stub_fr.sp());
407 }
408 #endif
409
410 JavaThread** frame::saved_thread_address(const frame& f) {
411 CodeBlob* cb = f.cb();
412 assert(cb != nullptr && cb->is_runtime_stub(), "invalid frame");
413
414 JavaThread** thread_addr;
415 #ifdef COMPILER1
416 if (cb == Runtime1::blob_for(StubId::c1_monitorenter_id) ||
417 cb == Runtime1::blob_for(StubId::c1_monitorenter_nofpu_id)) {
418 thread_addr = (JavaThread**)(f.sp() + Runtime1::runtime_blob_current_thread_offset(f));
419 } else
420 #endif
421 {
422 // c2 only saves rbp in the stub frame so nothing to do.
423 thread_addr = nullptr;
424 }
425 assert(get_register_address_in_stub(f, SharedRuntime::thread_register()) == (address)thread_addr, "wrong thread address");
426 return thread_addr;
427 }
428
429 //------------------------------------------------------------------------------
430 // frame::sender_for_interpreter_frame
431 frame frame::sender_for_interpreter_frame(RegisterMap* map) const {
432 // SP is the raw SP from the sender after adapter or interpreter
433 // extension.
434 intptr_t* sender_sp = this->sender_sp();
435
436 // This is the sp before any possible extension (adapter/locals).
437 intptr_t* unextended_sp = interpreter_frame_sender_sp();
438
439 #ifdef COMPILER2
440 assert(map != nullptr, "map must be set");
441 if (map->update_map()) {
442 update_map_with_saved_link(map, (intptr_t**) addr_at(link_offset));
443 }
444 #endif // COMPILER2
445
446 if (Continuation::is_return_barrier_entry(sender_pc())) {
447 if (map->walk_cont()) { // about to walk into an h-stack
448 return Continuation::top_frame(*this, map);
449 } else {
450 return Continuation::continuation_bottom_sender(map->thread(), *this, sender_sp);
451 }
452 }
453
454 return frame(sender_sp, unextended_sp, link(), sender_pc());
455 }
456
457 bool frame::is_interpreted_frame_valid(JavaThread* thread) const {
458 assert(is_interpreted_frame(), "Not an interpreted frame");
459 // These are reasonable sanity checks
460 if (fp() == nullptr || (intptr_t(fp()) & (wordSize-1)) != 0) {
461 return false;
462 }
463 if (sp() == nullptr || (intptr_t(sp()) & (wordSize-1)) != 0) {
464 return false;
465 }
466 if (fp() + interpreter_frame_initial_sp_offset < sp()) {
467 return false;
468 }
469 // These are hacks to keep us out of trouble.
470 // The problem with these is that they mask other problems
471 if (fp() <= sp()) { // this attempts to deal with unsigned comparison above
472 return false;
473 }
474
475 // do some validation of frame elements
476
477 // first the method
478 Method* m = safe_interpreter_frame_method();
479 // validate the method we'd find in this potential sender
480 if (!Method::is_valid_method(m)) {
481 return false;
482 }
483
484 // stack frames shouldn't be much larger than max_stack elements
485 // this test requires the use of unextended_sp which is the sp as seen by
486 // the current frame, and not sp which is the "raw" pc which could point
487 // further because of local variables of the callee method inserted after
488 // method arguments
489 if (fp() - unextended_sp() > 1024 + m->max_stack()*Interpreter::stackElementSize) {
490 return false;
491 }
492
493 // validate bci/bcx
494 address bcp = interpreter_frame_bcp();
495 if (m->validate_bci_from_bcp(bcp) < 0) {
496 return false;
497 }
498
499 // validate constantPoolCache*
500 ConstantPoolCache* cp = *interpreter_frame_cache_addr();
501 if (MetaspaceObj::is_valid(cp) == false) {
502 return false;
503 }
504
505 // validate locals
506 if (m->max_locals() > 0) {
507 address locals = (address)interpreter_frame_locals();
508 if (!thread->is_in_stack_range_incl(locals, (address)fp())) {
509 return false;
510 }
511 }
512
513 // We'd have to be pretty unlucky to be mislead at this point
514 return true;
515 }
516
517 BasicType frame::interpreter_frame_result(oop* oop_result, jvalue* value_result) {
518 assert(is_interpreted_frame(), "interpreted frame expected");
519 Method* method = interpreter_frame_method();
520 BasicType type = method->result_type();
521
522 intptr_t* tos_addr = nullptr;
523 if (method->is_native()) {
524 tos_addr = (intptr_t*)sp();
525 if (type == T_FLOAT || type == T_DOUBLE) {
526 // This is because we do a push(ltos) after push(dtos) in generate_native_entry.
527 tos_addr += 2 * Interpreter::stackElementWords;
528 }
529 } else {
530 tos_addr = (intptr_t*)interpreter_frame_tos_address();
531 }
532
533 switch (type) {
534 case T_OBJECT :
535 case T_ARRAY : {
536 oop obj;
537 if (method->is_native()) {
538 obj = cast_to_oop(at(interpreter_frame_oop_temp_offset));
539 } else {
540 oop* obj_p = (oop*)tos_addr;
541 obj = (obj_p == nullptr) ? (oop)nullptr : *obj_p;
542 }
543 assert(Universe::is_in_heap_or_null(obj), "sanity check");
544 *oop_result = obj;
545 break;
546 }
547 case T_BOOLEAN : value_result->z = *(jboolean*)tos_addr; break;
548 case T_BYTE : value_result->b = *(jbyte*)tos_addr; break;
549 case T_CHAR : value_result->c = *(jchar*)tos_addr; break;
550 case T_SHORT : value_result->s = *(jshort*)tos_addr; break;
551 case T_INT : value_result->i = *(jint*)tos_addr; break;
552 case T_LONG : value_result->j = *(jlong*)tos_addr; break;
553 case T_FLOAT : {
554 value_result->f = *(jfloat*)tos_addr;
555 break;
556 }
557 case T_DOUBLE : value_result->d = *(jdouble*)tos_addr; break;
558 case T_VOID : /* Nothing to do */ break;
559 default : ShouldNotReachHere();
560 }
561
562 return type;
563 }
564
565
566 intptr_t* frame::interpreter_frame_tos_at(jint offset) const {
567 int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);
568 return &interpreter_frame_tos_address()[index];
569 }
570
571 #ifndef PRODUCT
572
573 #define DESCRIBE_FP_OFFSET(name) \
574 values.describe(frame_no, fp() + frame::name##_offset, #name)
575
576 void frame::describe_pd(FrameValues& values, int frame_no) {
577 if (is_interpreted_frame()) {
578 DESCRIBE_FP_OFFSET(interpreter_frame_sender_sp);
579 DESCRIBE_FP_OFFSET(interpreter_frame_last_sp);
580 DESCRIBE_FP_OFFSET(interpreter_frame_method);
581 DESCRIBE_FP_OFFSET(interpreter_frame_mdp);
582 DESCRIBE_FP_OFFSET(interpreter_frame_extended_sp);
583 DESCRIBE_FP_OFFSET(interpreter_frame_mirror);
584 DESCRIBE_FP_OFFSET(interpreter_frame_cache);
585 DESCRIBE_FP_OFFSET(interpreter_frame_locals);
586 DESCRIBE_FP_OFFSET(interpreter_frame_bcp);
587 DESCRIBE_FP_OFFSET(interpreter_frame_initial_sp);
588 }
589
590 if (is_java_frame() || Continuation::is_continuation_enterSpecial(*this)) {
591 intptr_t* ret_pc_loc;
592 intptr_t* fp_loc;
593 if (is_interpreted_frame()) {
594 ret_pc_loc = fp() + return_addr_offset;
595 fp_loc = fp();
596 } else {
597 ret_pc_loc = real_fp() - 1;
598 fp_loc = real_fp() - 2;
599 }
600 address ret_pc = *(address*)ret_pc_loc;
601 values.describe(frame_no, ret_pc_loc,
602 Continuation::is_return_barrier_entry(ret_pc) ? "return address (return barrier)" : "return address");
603 values.describe(-1, fp_loc, "saved fp", 0); // "unowned" as value belongs to sender
604 }
605 }
606 #endif
607
608 intptr_t *frame::initial_deoptimization_info() {
609 // Not used on riscv, but we must return something.
610 return nullptr;
611 }
612
613 #undef DESCRIBE_FP_OFFSET
614
615 #ifndef PRODUCT
616 // This is a generic constructor which is only used by pns() in debug.cpp.
617 frame::frame(void* ptr_sp, void* ptr_fp, void* pc) : _on_heap(false) {
618 init((intptr_t*)ptr_sp, (intptr_t*)ptr_fp, (address)pc);
619 }
620
621 #endif
622
623 void JavaFrameAnchor::make_walkable() {
624 // last frame set?
625 if (last_Java_sp() == nullptr) { return; }
626 // already walkable?
627 if (walkable()) { return; }
628 vmassert(last_Java_sp() != nullptr, "not called from Java code?");
629 _last_Java_pc = (address)_last_Java_sp[-1];
630 vmassert(walkable(), "something went wrong");
631 }