1 /*
2 * Copyright (c) 2018, 2025, 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 "classfile/javaClasses.inline.hpp"
26 #include "classfile/vmSymbols.hpp"
27 #include "code/codeCache.inline.hpp"
28 #include "code/nmethod.inline.hpp"
29 #include "code/vmreg.inline.hpp"
30 #include "compiler/oopMap.inline.hpp"
31 #include "gc/shared/barrierSet.hpp"
32 #include "gc/shared/continuationGCSupport.inline.hpp"
33 #include "gc/shared/gc_globals.hpp"
34 #include "gc/shared/memAllocator.hpp"
35 #include "gc/shared/threadLocalAllocBuffer.inline.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "jfr/jfrEvents.hpp"
38 #include "logging/log.hpp"
39 #include "logging/logStream.hpp"
40 #include "oops/access.inline.hpp"
41 #include "oops/method.inline.hpp"
42 #include "oops/objArrayOop.inline.hpp"
43 #include "oops/oopsHierarchy.hpp"
44 #include "oops/stackChunkOop.inline.hpp"
45 #include "prims/jvmtiThreadState.hpp"
46 #include "runtime/arguments.hpp"
47 #include "runtime/continuation.hpp"
48 #include "runtime/continuationEntry.inline.hpp"
49 #include "runtime/continuationHelper.inline.hpp"
50 #include "runtime/continuationJavaClasses.inline.hpp"
51 #include "runtime/continuationWrapper.inline.hpp"
52 #include "runtime/frame.inline.hpp"
53 #include "runtime/interfaceSupport.inline.hpp"
54 #include "runtime/javaThread.inline.hpp"
55 #include "runtime/jniHandles.inline.hpp"
56 #include "runtime/keepStackGCProcessed.hpp"
57 #include "runtime/objectMonitor.inline.hpp"
58 #include "runtime/orderAccess.hpp"
59 #include "runtime/prefetch.inline.hpp"
60 #include "runtime/sharedRuntime.hpp"
61 #include "runtime/smallRegisterMap.inline.hpp"
62 #include "runtime/stackChunkFrameStream.inline.hpp"
63 #include "runtime/stackFrameStream.inline.hpp"
64 #include "runtime/stackOverflow.hpp"
65 #include "runtime/stackWatermarkSet.inline.hpp"
66 #include "utilities/debug.hpp"
67 #include "utilities/exceptions.hpp"
68 #include "utilities/macros.hpp"
69 #include "utilities/vmError.hpp"
70 #if INCLUDE_ZGC
71 #include "gc/z/zStackChunkGCData.inline.hpp"
72 #endif
73 #if INCLUDE_JFR
74 #include "jfr/jfr.inline.hpp"
75 #endif
76
77 #include <type_traits>
78
79 /*
80 * This file contains the implementation of continuation freezing (yield) and thawing (run).
81 *
82 * This code is very latency-critical and very hot. An ordinary and well-behaved server application
83 * would likely call these operations many thousands of times per second second, on every core.
84 *
85 * Freeze might be called every time the application performs any I/O operation, every time it
86 * acquires a j.u.c. lock, every time it takes a message from a queue, and thaw can be called
87 * multiple times in each of those cases, as it is called by the return barrier, which may be
88 * invoked on method return.
89 *
90 * The amortized budget for each of those two operations is ~100-150ns. That is why, for
91 * example, every effort is made to avoid Java-VM transitions as much as possible.
92 *
93 * On the fast path, all frames are known to be compiled, and the chunk requires no barriers
94 * and so frames simply copied, and the bottom-most one is patched.
95 * On the slow path, internal pointers in interpreted frames are de/relativized to/from offsets
96 * and absolute pointers, and barriers invoked.
97 */
98
99 /************************************************
100
101 Thread-stack layout on freeze/thaw.
102 See corresponding stack-chunk layout in instanceStackChunkKlass.hpp
103
104 +----------------------------+
105 | . |
106 | . |
107 | . |
108 | carrier frames |
109 | |
110 |----------------------------|
111 | |
112 | Continuation.run |
113 | |
114 |============================|
115 | enterSpecial frame |
116 | pc |
117 | rbp |
118 | ----- |
119 ^ | int argsize | = ContinuationEntry
120 | | oopDesc* cont |
121 | | oopDesc* chunk |
122 | | ContinuationEntry* parent |
123 | | ... |
124 | |============================| <------ JavaThread::_cont_entry = entry->sp()
125 | | ? alignment word ? |
126 | |----------------------------| <--\
127 | | | |
128 | | ? caller stack args ? | | argsize (might not be 2-word aligned) words
129 Address | | | | Caller is still in the chunk.
130 | |----------------------------| |
131 | | pc (? return barrier ?) | | This pc contains the return barrier when the bottom-most frame
132 | | rbp | | isn't the last one in the continuation.
133 | | | |
134 | | frame | |
135 | | | |
136 +----------------------------| \__ Continuation frames to be frozen/thawed
137 | | /
138 | frame | |
139 | | |
140 |----------------------------| |
141 | | |
142 | frame | |
143 | | |
144 |----------------------------| <--/
145 | |
146 | doYield/safepoint stub | When preempting forcefully, we could have a safepoint stub
147 | | instead of a doYield stub
148 |============================| <- the sp passed to freeze
149 | |
150 | Native freeze/thaw frames |
151 | . |
152 | . |
153 | . |
154 +----------------------------+
155
156 ************************************************/
157
158 static const bool TEST_THAW_ONE_CHUNK_FRAME = false; // force thawing frames one-at-a-time for testing
159
160 #define CONT_JFR false // emit low-level JFR events that count slow/fast path for continuation performance debugging only
161 #if CONT_JFR
162 #define CONT_JFR_ONLY(code) code
163 #else
164 #define CONT_JFR_ONLY(code)
165 #endif
166
167 // TODO: See AbstractAssembler::generate_stack_overflow_check,
168 // Compile::bang_size_in_bytes(), m->as_SafePoint()->jvms()->interpreter_frame_size()
169 // when we stack-bang, we need to update a thread field with the lowest (farthest) bang point.
170
171 // Data invariants are defined by Continuation::debug_verify_continuation and Continuation::debug_verify_stack_chunk
172
173 // Used to just annotatate cold/hot branches
174 #define LIKELY(condition) (condition)
175 #define UNLIKELY(condition) (condition)
176
177 // debugging functions
178 #ifdef ASSERT
179 extern "C" bool dbg_is_safe(const void* p, intptr_t errvalue); // address p is readable and *(intptr_t*)p != errvalue
180
181 static void verify_continuation(oop continuation) { Continuation::debug_verify_continuation(continuation); }
182
183 static void do_deopt_after_thaw(JavaThread* thread);
184 static bool do_verify_after_thaw(JavaThread* thread, stackChunkOop chunk, outputStream* st);
185 static void log_frames(JavaThread* thread);
186 static void log_frames_after_thaw(JavaThread* thread, ContinuationWrapper& cont, intptr_t* sp, bool preempted);
187 static void print_frame_layout(const frame& f, bool callee_complete, outputStream* st = tty);
188
189 #define assert_pfl(p, ...) \
190 do { \
191 if (!(p)) { \
192 JavaThread* t = JavaThread::active(); \
193 if (t->has_last_Java_frame()) { \
194 tty->print_cr("assert(" #p ") failed:"); \
195 t->print_frame_layout(); \
196 } \
197 } \
198 vmassert(p, __VA_ARGS__); \
199 } while(0)
200
201 #else
202 static void verify_continuation(oop continuation) { }
203 #define assert_pfl(p, ...)
204 #endif
205
206 static freeze_result is_pinned0(JavaThread* thread, oop cont_scope, bool safepoint);
207 template<typename ConfigT, bool preempt> static inline freeze_result freeze_internal(JavaThread* current, intptr_t* const sp);
208
209 static inline int prepare_thaw_internal(JavaThread* thread, bool return_barrier);
210 template<typename ConfigT> static inline intptr_t* thaw_internal(JavaThread* thread, const Continuation::thaw_kind kind);
211
212
213 // Entry point to freeze. Transitions are handled manually
214 // Called from gen_continuation_yield() in sharedRuntime_<cpu>.cpp through Continuation::freeze_entry();
215 template<typename ConfigT>
216 static JRT_BLOCK_ENTRY(int, freeze(JavaThread* current, intptr_t* sp))
217 assert(sp == current->frame_anchor()->last_Java_sp(), "");
218
219 if (current->raw_cont_fastpath() > current->last_continuation()->entry_sp() || current->raw_cont_fastpath() < sp) {
220 current->set_cont_fastpath(nullptr);
221 }
222
223 return checked_cast<int>(ConfigT::freeze(current, sp));
224 JRT_END
225
226 JRT_LEAF(int, Continuation::prepare_thaw(JavaThread* thread, bool return_barrier))
227 return prepare_thaw_internal(thread, return_barrier);
228 JRT_END
229
230 template<typename ConfigT>
231 static JRT_LEAF(intptr_t*, thaw(JavaThread* thread, int kind))
232 // TODO: JRT_LEAF and NoHandleMark is problematic for JFR events.
233 // vFrameStreamCommon allocates Handles in RegisterMap for continuations.
234 // Also the preemption case with JVMTI events enabled might safepoint so
235 // undo the NoSafepointVerifier here and rely on handling by ContinuationWrapper.
236 // JRT_ENTRY instead?
237 ResetNoHandleMark rnhm;
238 DEBUG_ONLY(PauseNoSafepointVerifier pnsv(&__nsv);)
239
240 // we might modify the code cache via BarrierSetNMethod::nmethod_entry_barrier
241 MACOS_AARCH64_ONLY(ThreadWXEnable __wx(WXWrite, thread));
242 return ConfigT::thaw(thread, (Continuation::thaw_kind)kind);
243 JRT_END
244
245 JVM_ENTRY(jint, CONT_isPinned0(JNIEnv* env, jobject cont_scope)) {
246 JavaThread* thread = JavaThread::thread_from_jni_environment(env);
247 return is_pinned0(thread, JNIHandles::resolve(cont_scope), false);
248 }
249 JVM_END
250
251 ///////////
252
253 enum class oop_kind { NARROW, WIDE };
254 template <oop_kind oops, typename BarrierSetT>
255 class Config {
256 public:
257 typedef Config<oops, BarrierSetT> SelfT;
258 using OopT = std::conditional_t<oops == oop_kind::NARROW, narrowOop, oop>;
259
260 static freeze_result freeze(JavaThread* thread, intptr_t* const sp) {
261 freeze_result res = freeze_internal<SelfT, false>(thread, sp);
262 JFR_ONLY(assert((res == freeze_ok) || (res == thread->last_freeze_fail_result()), "freeze failure not set"));
263 return res;
264 }
265
266 static freeze_result freeze_preempt(JavaThread* thread, intptr_t* const sp) {
267 return freeze_internal<SelfT, true>(thread, sp);
268 }
269
270 static intptr_t* thaw(JavaThread* thread, Continuation::thaw_kind kind) {
271 return thaw_internal<SelfT>(thread, kind);
272 }
273 };
274
275 #ifdef _WINDOWS
276 static void map_stack_pages(JavaThread* thread, size_t size, address sp) {
277 address new_sp = sp - size;
278 address watermark = thread->stack_overflow_state()->shadow_zone_growth_watermark();
279
280 if (new_sp < watermark) {
281 size_t page_size = os::vm_page_size();
282 address last_touched_page = watermark - StackOverflow::stack_shadow_zone_size();
283 size_t pages_to_touch = align_up(watermark - new_sp, page_size) / page_size;
284 while (pages_to_touch-- > 0) {
285 last_touched_page -= page_size;
286 *last_touched_page = 0;
287 }
288 thread->stack_overflow_state()->set_shadow_zone_growth_watermark(new_sp);
289 }
290 }
291 #endif
292
293 static bool stack_overflow_check(JavaThread* thread, size_t size, address sp) {
294 const size_t page_size = os::vm_page_size();
295 if (size > page_size) {
296 if (sp - size < thread->stack_overflow_state()->shadow_zone_safe_limit()) {
297 return false;
298 }
299 WINDOWS_ONLY(map_stack_pages(thread, size, sp));
300 }
301 return true;
302 }
303
304 #ifdef ASSERT
305 static oop get_continuation(JavaThread* thread) {
306 assert(thread != nullptr, "");
307 assert(thread->threadObj() != nullptr, "");
308 return java_lang_Thread::continuation(thread->threadObj());
309 }
310 #endif // ASSERT
311
312 inline void clear_anchor(JavaThread* thread) {
313 thread->frame_anchor()->clear();
314 }
315
316 static void set_anchor(JavaThread* thread, intptr_t* sp, address pc) {
317 assert(pc != nullptr, "");
318
319 JavaFrameAnchor* anchor = thread->frame_anchor();
320 anchor->set_last_Java_sp(sp);
321 anchor->set_last_Java_pc(pc);
322 ContinuationHelper::set_anchor_pd(anchor, sp);
323
324 assert(thread->has_last_Java_frame(), "");
325 assert(thread->last_frame().cb() != nullptr, "");
326 }
327
328 static void set_anchor(JavaThread* thread, intptr_t* sp) {
329 address pc = ContinuationHelper::return_address_at(
330 sp - frame::sender_sp_ret_address_offset());
331 set_anchor(thread, sp, pc);
332 }
333
334 static void set_anchor_to_entry(JavaThread* thread, ContinuationEntry* entry) {
335 JavaFrameAnchor* anchor = thread->frame_anchor();
336 anchor->set_last_Java_sp(entry->entry_sp());
337 anchor->set_last_Java_pc(entry->entry_pc());
338 ContinuationHelper::set_anchor_to_entry_pd(anchor, entry);
339
340 assert(thread->has_last_Java_frame(), "");
341 assert(thread->last_frame().cb() != nullptr, "");
342 }
343
344 #if CONT_JFR
345 class FreezeThawJfrInfo : public StackObj {
346 short _e_size;
347 short _e_num_interpreted_frames;
348 public:
349
350 FreezeThawJfrInfo() : _e_size(0), _e_num_interpreted_frames(0) {}
351 inline void record_interpreted_frame() { _e_num_interpreted_frames++; }
352 inline void record_size_copied(int size) { _e_size += size << LogBytesPerWord; }
353 template<typename Event> void post_jfr_event(Event *e, oop continuation, JavaThread* jt);
354 };
355
356 template<typename Event> void FreezeThawJfrInfo::post_jfr_event(Event* e, oop continuation, JavaThread* jt) {
357 if (e->should_commit()) {
358 log_develop_trace(continuations)("JFR event: iframes: %d size: %d", _e_num_interpreted_frames, _e_size);
359 e->set_carrierThread(JFR_JVM_THREAD_ID(jt));
360 e->set_continuationClass(continuation->klass());
361 e->set_interpretedFrames(_e_num_interpreted_frames);
362 e->set_size(_e_size);
363 e->commit();
364 }
365 }
366 #endif // CONT_JFR
367
368 /////////////// FREEZE ////
369
370 class FreezeBase : public StackObj {
371 protected:
372 JavaThread* const _thread;
373 ContinuationWrapper& _cont;
374 bool _barriers; // only set when we allocate a chunk
375
376 intptr_t* _bottom_address;
377
378 // Used for preemption only
379 const bool _preempt;
380 frame _last_frame;
381
382 // Used to support freezing with held monitors
383 int _monitors_in_lockstack;
384
385 int _freeze_size; // total size of all frames plus metadata in words.
386 int _total_align_size;
387
388 intptr_t* _cont_stack_top;
389 intptr_t* _cont_stack_bottom;
390
391 CONT_JFR_ONLY(FreezeThawJfrInfo _jfr_info;)
392
393 #ifdef ASSERT
394 intptr_t* _orig_chunk_sp;
395 int _fast_freeze_size;
396 bool _empty;
397 #endif
398
399 JvmtiSampledObjectAllocEventCollector* _jvmti_event_collector;
400
401 NOT_PRODUCT(int _frames;)
402 DEBUG_ONLY(intptr_t* _last_write;)
403
404 inline FreezeBase(JavaThread* thread, ContinuationWrapper& cont, intptr_t* sp, bool preempt);
405
406 public:
407 NOINLINE freeze_result freeze_slow();
408 void freeze_fast_existing_chunk();
409
410 CONT_JFR_ONLY(FreezeThawJfrInfo& jfr_info() { return _jfr_info; })
411 void set_jvmti_event_collector(JvmtiSampledObjectAllocEventCollector* jsoaec) { _jvmti_event_collector = jsoaec; }
412
413 inline int size_if_fast_freeze_available();
414
415 inline frame& last_frame() { return _last_frame; }
416
417 #ifdef ASSERT
418 bool check_valid_fast_path();
419 #endif
420
421 protected:
422 inline void init_rest();
423 void throw_stack_overflow_on_humongous_chunk();
424
425 // fast path
426 inline void copy_to_chunk(intptr_t* from, intptr_t* to, int size);
427 inline void unwind_frames();
428 inline void patch_stack_pd(intptr_t* frame_sp, intptr_t* heap_sp);
429
430 // slow path
431 virtual stackChunkOop allocate_chunk_slow(size_t stack_size, int argsize_md) = 0;
432
433 int cont_size() { return pointer_delta_as_int(_cont_stack_bottom, _cont_stack_top); }
434
435 private:
436 // slow path
437 frame freeze_start_frame();
438 frame freeze_start_frame_on_preempt();
439 NOINLINE freeze_result recurse_freeze(frame& f, frame& caller, int callee_argsize, bool callee_interpreted, bool top);
440 inline frame freeze_start_frame_yield_stub();
441 template<typename FKind>
442 inline freeze_result recurse_freeze_java_frame(const frame& f, frame& caller, int fsize, int argsize);
443 inline void before_freeze_java_frame(const frame& f, const frame& caller, int fsize, int argsize, bool is_bottom_frame);
444 inline void after_freeze_java_frame(const frame& hf, bool is_bottom_frame);
445 freeze_result finalize_freeze(const frame& callee, frame& caller, int argsize);
446 void patch(const frame& f, frame& hf, const frame& caller, bool is_bottom_frame);
447 NOINLINE freeze_result recurse_freeze_interpreted_frame(frame& f, frame& caller, int callee_argsize, bool callee_interpreted);
448 freeze_result recurse_freeze_compiled_frame(frame& f, frame& caller, int callee_argsize, bool callee_interpreted);
449 NOINLINE freeze_result recurse_freeze_stub_frame(frame& f, frame& caller);
450 NOINLINE freeze_result recurse_freeze_native_frame(frame& f, frame& caller);
451 NOINLINE void finish_freeze(const frame& f, const frame& top);
452
453 void freeze_lockstack(stackChunkOop chunk);
454
455 inline bool stack_overflow();
456
457 static frame sender(const frame& f) { return f.is_interpreted_frame() ? sender<ContinuationHelper::InterpretedFrame>(f)
458 : sender<ContinuationHelper::NonInterpretedUnknownFrame>(f); }
459 template<typename FKind> static inline frame sender(const frame& f);
460 template<typename FKind> frame new_heap_frame(frame& f, frame& caller);
461 inline void set_top_frame_metadata_pd(const frame& hf);
462 inline void patch_pd(frame& callee, const frame& caller);
463 inline void patch_pd_unused(intptr_t* sp);
464 void adjust_interpreted_frame_unextended_sp(frame& f);
465 static inline void prepare_freeze_interpreted_top_frame(frame& f);
466 static inline void relativize_interpreted_frame_metadata(const frame& f, const frame& hf);
467
468 protected:
469 void freeze_fast_copy(stackChunkOop chunk, int chunk_start_sp CONT_JFR_ONLY(COMMA bool chunk_is_allocated));
470 bool freeze_fast_new_chunk(stackChunkOop chunk);
471 };
472
473 template <typename ConfigT>
474 class Freeze : public FreezeBase {
475 private:
476 stackChunkOop allocate_chunk(size_t stack_size, int argsize_md);
477
478 public:
479 inline Freeze(JavaThread* thread, ContinuationWrapper& cont, intptr_t* frame_sp, bool preempt)
480 : FreezeBase(thread, cont, frame_sp, preempt) {}
481
482 freeze_result try_freeze_fast();
483
484 protected:
485 virtual stackChunkOop allocate_chunk_slow(size_t stack_size, int argsize_md) override { return allocate_chunk(stack_size, argsize_md); }
486 };
487
488 FreezeBase::FreezeBase(JavaThread* thread, ContinuationWrapper& cont, intptr_t* frame_sp, bool preempt) :
489 _thread(thread), _cont(cont), _barriers(false), _preempt(preempt), _last_frame(false /* no initialization */) {
490 DEBUG_ONLY(_jvmti_event_collector = nullptr;)
491
492 assert(_thread != nullptr, "");
493 assert(_thread->last_continuation()->entry_sp() == _cont.entrySP(), "");
494
495 DEBUG_ONLY(_cont.entry()->verify_cookie();)
496
497 assert(!Interpreter::contains(_cont.entryPC()), "");
498
499 _bottom_address = _cont.entrySP() - _cont.entry_frame_extension();
500 #ifdef _LP64
501 if (((intptr_t)_bottom_address & 0xf) != 0) {
502 _bottom_address--;
503 }
504 assert(is_aligned(_bottom_address, frame::frame_alignment), "");
505 #endif
506
507 log_develop_trace(continuations)("bottom_address: " INTPTR_FORMAT " entrySP: " INTPTR_FORMAT " argsize: " PTR_FORMAT,
508 p2i(_bottom_address), p2i(_cont.entrySP()), (_cont.entrySP() - _bottom_address) << LogBytesPerWord);
509 assert(_bottom_address != nullptr, "");
510 assert(_bottom_address <= _cont.entrySP(), "");
511 DEBUG_ONLY(_last_write = nullptr;)
512
513 assert(_cont.chunk_invariant(), "");
514 assert(!Interpreter::contains(_cont.entryPC()), "");
515 #if !defined(PPC64) || defined(ZERO)
516 static const int doYield_stub_frame_size = frame::metadata_words;
517 #else
518 static const int doYield_stub_frame_size = frame::native_abi_reg_args_size >> LogBytesPerWord;
519 #endif
520 // With preemption doYield() might not have been resolved yet
521 assert(_preempt || SharedRuntime::cont_doYield_stub()->frame_size() == doYield_stub_frame_size, "");
522
523 if (preempt) {
524 _last_frame = _thread->last_frame();
525 }
526
527 // properties of the continuation on the stack; all sizes are in words
528 _cont_stack_top = frame_sp + (!preempt ? doYield_stub_frame_size : 0); // we don't freeze the doYield stub frame
529 _cont_stack_bottom = _cont.entrySP() + (_cont.argsize() == 0 ? frame::metadata_words_at_top : 0)
530 - ContinuationHelper::frame_align_words(_cont.argsize()); // see alignment in thaw
531
532 log_develop_trace(continuations)("freeze size: %d argsize: %d top: " INTPTR_FORMAT " bottom: " INTPTR_FORMAT,
533 cont_size(), _cont.argsize(), p2i(_cont_stack_top), p2i(_cont_stack_bottom));
534 assert(cont_size() > 0, "");
535
536 if (LockingMode != LM_LIGHTWEIGHT) {
537 _monitors_in_lockstack = 0;
538 } else {
539 _monitors_in_lockstack = _thread->lock_stack().monitor_count();
540 }
541 }
542
543 void FreezeBase::init_rest() { // we want to postpone some initialization after chunk handling
544 _freeze_size = 0;
545 _total_align_size = 0;
546 NOT_PRODUCT(_frames = 0;)
547 }
548
549 void FreezeBase::freeze_lockstack(stackChunkOop chunk) {
550 assert(chunk->sp_address() - chunk->start_address() >= _monitors_in_lockstack, "no room for lockstack");
551
552 _thread->lock_stack().move_to_address((oop*)chunk->start_address());
553 chunk->set_lockstack_size(checked_cast<uint8_t>(_monitors_in_lockstack));
554 chunk->set_has_lockstack(true);
555 }
556
557 void FreezeBase::copy_to_chunk(intptr_t* from, intptr_t* to, int size) {
558 stackChunkOop chunk = _cont.tail();
559 chunk->copy_from_stack_to_chunk(from, to, size);
560 CONT_JFR_ONLY(_jfr_info.record_size_copied(size);)
561
562 #ifdef ASSERT
563 if (_last_write != nullptr) {
564 assert(_last_write == to + size, "Missed a spot: _last_write: " INTPTR_FORMAT " to+size: " INTPTR_FORMAT
565 " stack_size: %d _last_write offset: " PTR_FORMAT " to+size: " PTR_FORMAT, p2i(_last_write), p2i(to+size),
566 chunk->stack_size(), _last_write-chunk->start_address(), to+size-chunk->start_address());
567 _last_write = to;
568 }
569 #endif
570 }
571
572 static void assert_frames_in_continuation_are_safe(JavaThread* thread) {
573 #ifdef ASSERT
574 StackWatermark* watermark = StackWatermarkSet::get(thread, StackWatermarkKind::gc);
575 if (watermark == nullptr) {
576 return;
577 }
578 ContinuationEntry* ce = thread->last_continuation();
579 RegisterMap map(thread,
580 RegisterMap::UpdateMap::include,
581 RegisterMap::ProcessFrames::skip,
582 RegisterMap::WalkContinuation::skip);
583 map.set_include_argument_oops(false);
584 for (frame f = thread->last_frame(); Continuation::is_frame_in_continuation(ce, f); f = f.sender(&map)) {
585 watermark->assert_is_frame_safe(f);
586 }
587 #endif // ASSERT
588 }
589
590 #ifdef ASSERT
591 static bool monitors_on_stack(JavaThread* thread) {
592 assert_frames_in_continuation_are_safe(thread);
593 ContinuationEntry* ce = thread->last_continuation();
594 RegisterMap map(thread,
595 RegisterMap::UpdateMap::include,
596 RegisterMap::ProcessFrames::skip,
597 RegisterMap::WalkContinuation::skip);
598 map.set_include_argument_oops(false);
599 for (frame f = thread->last_frame(); Continuation::is_frame_in_continuation(ce, f); f = f.sender(&map)) {
600 if ((f.is_interpreted_frame() && ContinuationHelper::InterpretedFrame::is_owning_locks(f)) ||
601 (f.is_compiled_frame() && ContinuationHelper::CompiledFrame::is_owning_locks(map.thread(), &map, f)) ||
602 (f.is_native_frame() && ContinuationHelper::NativeFrame::is_owning_locks(map.thread(), f))) {
603 return true;
604 }
605 }
606 return false;
607 }
608 #endif // ASSERT
609
610 // Called _after_ the last possible safepoint during the freeze operation (chunk allocation)
611 void FreezeBase::unwind_frames() {
612 ContinuationEntry* entry = _cont.entry();
613 entry->flush_stack_processing(_thread);
614 assert_frames_in_continuation_are_safe(_thread);
615 JFR_ONLY(Jfr::check_and_process_sample_request(_thread);)
616 assert(LockingMode != LM_LEGACY || !monitors_on_stack(_thread), "unexpected monitors on stack");
617 set_anchor_to_entry(_thread, entry);
618 }
619
620 template <typename ConfigT>
621 freeze_result Freeze<ConfigT>::try_freeze_fast() {
622 assert(_thread->thread_state() == _thread_in_vm, "");
623 assert(_thread->cont_fastpath(), "");
624
625 DEBUG_ONLY(_fast_freeze_size = size_if_fast_freeze_available();)
626 assert(_fast_freeze_size == 0, "");
627
628 stackChunkOop chunk = allocate_chunk(cont_size() + frame::metadata_words + _monitors_in_lockstack, _cont.argsize() + frame::metadata_words_at_top);
629 if (freeze_fast_new_chunk(chunk)) {
630 return freeze_ok;
631 }
632 if (_thread->has_pending_exception()) {
633 return freeze_exception;
634 }
635
636 // TODO R REMOVE when deopt change is fixed
637 assert(!_thread->cont_fastpath() || _barriers, "");
638 log_develop_trace(continuations)("-- RETRYING SLOW --");
639 return freeze_slow();
640 }
641
642 // Returns size needed if the continuation fits, otherwise 0.
643 int FreezeBase::size_if_fast_freeze_available() {
644 stackChunkOop chunk = _cont.tail();
645 if (chunk == nullptr || chunk->is_gc_mode() || chunk->requires_barriers() || chunk->has_mixed_frames()) {
646 log_develop_trace(continuations)("chunk available %s", chunk == nullptr ? "no chunk" : "chunk requires barriers");
647 return 0;
648 }
649
650 int total_size_needed = cont_size();
651 const int chunk_sp = chunk->sp();
652
653 // argsize can be nonzero if we have a caller, but the caller could be in a non-empty parent chunk,
654 // so we subtract it only if we overlap with the caller, i.e. the current chunk isn't empty.
655 // Consider leaving the chunk's argsize set when emptying it and removing the following branch,
656 // although that would require changing stackChunkOopDesc::is_empty
657 if (!chunk->is_empty()) {
658 total_size_needed -= _cont.argsize() + frame::metadata_words_at_top;
659 }
660
661 total_size_needed += _monitors_in_lockstack;
662
663 int chunk_free_room = chunk_sp - frame::metadata_words_at_bottom;
664 bool available = chunk_free_room >= total_size_needed;
665 log_develop_trace(continuations)("chunk available: %s size: %d argsize: %d top: " INTPTR_FORMAT " bottom: " INTPTR_FORMAT,
666 available ? "yes" : "no" , total_size_needed, _cont.argsize(), p2i(_cont_stack_top), p2i(_cont_stack_bottom));
667 return available ? total_size_needed : 0;
668 }
669
670 void FreezeBase::freeze_fast_existing_chunk() {
671 stackChunkOop chunk = _cont.tail();
672
673 DEBUG_ONLY(_fast_freeze_size = size_if_fast_freeze_available();)
674 assert(_fast_freeze_size > 0, "");
675
676 if (!chunk->is_empty()) { // we are copying into a non-empty chunk
677 DEBUG_ONLY(_empty = false;)
678 DEBUG_ONLY(_orig_chunk_sp = chunk->sp_address();)
679 #ifdef ASSERT
680 {
681 intptr_t* retaddr_slot = (chunk->sp_address()
682 - frame::sender_sp_ret_address_offset());
683 assert(ContinuationHelper::return_address_at(retaddr_slot) == chunk->pc(),
684 "unexpected saved return address");
685 }
686 #endif
687
688 // the chunk's sp before the freeze, adjusted to point beyond the stack-passed arguments in the topmost frame
689 // we overlap; we'll overwrite the chunk's top frame's callee arguments
690 const int chunk_start_sp = chunk->sp() + _cont.argsize() + frame::metadata_words_at_top;
691 assert(chunk_start_sp <= chunk->stack_size(), "sp not pointing into stack");
692
693 // increase max_size by what we're freezing minus the overlap
694 chunk->set_max_thawing_size(chunk->max_thawing_size() + cont_size() - _cont.argsize() - frame::metadata_words_at_top);
695
696 intptr_t* const bottom_sp = _cont_stack_bottom - _cont.argsize() - frame::metadata_words_at_top;
697 assert(bottom_sp == _bottom_address, "");
698 // Because the chunk isn't empty, we know there's a caller in the chunk, therefore the bottom-most frame
699 // should have a return barrier (installed back when we thawed it).
700 #ifdef ASSERT
701 {
702 intptr_t* retaddr_slot = (bottom_sp
703 - frame::sender_sp_ret_address_offset());
704 assert(ContinuationHelper::return_address_at(retaddr_slot)
705 == StubRoutines::cont_returnBarrier(),
706 "should be the continuation return barrier");
707 }
708 #endif
709 // We copy the fp from the chunk back to the stack because it contains some caller data,
710 // including, possibly, an oop that might have gone stale since we thawed.
711 patch_stack_pd(bottom_sp, chunk->sp_address());
712 // we don't patch the return pc at this time, so as not to make the stack unwalkable for async walks
713
714 freeze_fast_copy(chunk, chunk_start_sp CONT_JFR_ONLY(COMMA false));
715 } else { // the chunk is empty
716 const int chunk_start_sp = chunk->stack_size();
717
718 DEBUG_ONLY(_empty = true;)
719 DEBUG_ONLY(_orig_chunk_sp = chunk->start_address() + chunk_start_sp;)
720
721 chunk->set_max_thawing_size(cont_size());
722 chunk->set_bottom(chunk_start_sp - _cont.argsize() - frame::metadata_words_at_top);
723 chunk->set_sp(chunk->bottom());
724
725 freeze_fast_copy(chunk, chunk_start_sp CONT_JFR_ONLY(COMMA false));
726 }
727 }
728
729 bool FreezeBase::freeze_fast_new_chunk(stackChunkOop chunk) {
730 DEBUG_ONLY(_empty = true;)
731
732 // Install new chunk
733 _cont.set_tail(chunk);
734
735 if (UNLIKELY(chunk == nullptr || !_thread->cont_fastpath() || _barriers)) { // OOME/probably humongous
736 log_develop_trace(continuations)("Retrying slow. Barriers: %d", _barriers);
737 return false;
738 }
739
740 chunk->set_max_thawing_size(cont_size());
741
742 // in a fresh chunk, we freeze *with* the bottom-most frame's stack arguments.
743 // They'll then be stored twice: in the chunk and in the parent chunk's top frame
744 const int chunk_start_sp = cont_size() + frame::metadata_words + _monitors_in_lockstack;
745 assert(chunk_start_sp == chunk->stack_size(), "");
746
747 DEBUG_ONLY(_orig_chunk_sp = chunk->start_address() + chunk_start_sp;)
748
749 freeze_fast_copy(chunk, chunk_start_sp CONT_JFR_ONLY(COMMA true));
750
751 return true;
752 }
753
754 void FreezeBase::freeze_fast_copy(stackChunkOop chunk, int chunk_start_sp CONT_JFR_ONLY(COMMA bool chunk_is_allocated)) {
755 assert(chunk != nullptr, "");
756 assert(!chunk->has_mixed_frames(), "");
757 assert(!chunk->is_gc_mode(), "");
758 assert(!chunk->has_bitmap(), "");
759 assert(!chunk->requires_barriers(), "");
760 assert(chunk == _cont.tail(), "");
761
762 // We unwind frames after the last safepoint so that the GC will have found the oops in the frames, but before
763 // writing into the chunk. This is so that an asynchronous stack walk (not at a safepoint) that suspends us here
764 // will either see no continuation on the stack, or a consistent chunk.
765 unwind_frames();
766
767 log_develop_trace(continuations)("freeze_fast start: chunk " INTPTR_FORMAT " size: %d orig sp: %d argsize: %d",
768 p2i((oopDesc*)chunk), chunk->stack_size(), chunk_start_sp, _cont.argsize());
769 assert(chunk_start_sp <= chunk->stack_size(), "");
770 assert(chunk_start_sp >= cont_size(), "no room in the chunk");
771
772 const int chunk_new_sp = chunk_start_sp - cont_size(); // the chunk's new sp, after freeze
773 assert(!(_fast_freeze_size > 0) || (_orig_chunk_sp - (chunk->start_address() + chunk_new_sp)) == (_fast_freeze_size - _monitors_in_lockstack), "");
774
775 intptr_t* chunk_top = chunk->start_address() + chunk_new_sp;
776 #ifdef ASSERT
777 if (!_empty) {
778 intptr_t* retaddr_slot = (_orig_chunk_sp
779 - frame::sender_sp_ret_address_offset());
780 assert(ContinuationHelper::return_address_at(retaddr_slot) == chunk->pc(),
781 "unexpected saved return address");
782 }
783 #endif
784
785 log_develop_trace(continuations)("freeze_fast start: " INTPTR_FORMAT " sp: %d chunk_top: " INTPTR_FORMAT,
786 p2i(chunk->start_address()), chunk_new_sp, p2i(chunk_top));
787
788 int adjust = frame::metadata_words_at_bottom;
789 #if INCLUDE_ASAN && defined(AARCH64)
790 // Reading at offset frame::metadata_words_at_bottom from _cont_stack_top
791 // will accesss memory at the callee frame, which on preemption cases will
792 // be the VM native method being called. The Arm 64-bit ABI doesn't specify
793 // a location where the frame record (returnpc+fp) has to be stored within
794 // a stack frame, and GCC currently chooses to save it at the top of the
795 // frame (lowest address). ASan treats this memory access in the callee as
796 // an overflow access to one of the locals stored in that frame. For these
797 // preemption cases we don't need to read these words anyways so we avoid it.
798 if (_preempt) {
799 adjust = 0;
800 }
801 #endif
802 intptr_t* from = _cont_stack_top - adjust;
803 intptr_t* to = chunk_top - adjust;
804 copy_to_chunk(from, to, cont_size() + adjust);
805 // Because we're not patched yet, the chunk is now in a bad state
806
807 // patch return pc of the bottom-most frozen frame (now in the chunk)
808 // with the actual caller's return address
809 intptr_t* chunk_bottom_retaddr_slot = (chunk_top + cont_size()
810 - _cont.argsize()
811 - frame::metadata_words_at_top
812 - frame::sender_sp_ret_address_offset());
813 #ifdef ASSERT
814 if (!_empty) {
815 assert(ContinuationHelper::return_address_at(chunk_bottom_retaddr_slot)
816 == StubRoutines::cont_returnBarrier(),
817 "should be the continuation return barrier");
818 }
819 #endif
820 ContinuationHelper::patch_return_address_at(chunk_bottom_retaddr_slot,
821 chunk->pc());
822
823 // We're always writing to a young chunk, so the GC can't see it until the next safepoint.
824 chunk->set_sp(chunk_new_sp);
825
826 // set chunk->pc to the return address of the topmost frame in the chunk
827 if (_preempt) {
828 // On aarch64/riscv64, the return pc of the top frame won't necessarily be at sp[-1].
829 // Also, on x64, if the top frame is the native wrapper frame, sp[-1] will not
830 // be the pc we used when creating the oopmap. Get the top's frame last pc from
831 // the anchor instead.
832 address last_pc = _last_frame.pc();
833 ContinuationHelper::patch_return_address_at(chunk_top - frame::sender_sp_ret_address_offset(), last_pc);
834 chunk->set_pc(last_pc);
835 // For stub/native frames the fp is not used while frozen, and will be constructed
836 // again when thawing the frame (see ThawBase::handle_preempted_continuation). We
837 // patch it with a special bad address to help with debugging, particularly when
838 // inspecting frames and identifying invalid accesses.
839 patch_pd_unused(chunk_top);
840 } else {
841 chunk->set_pc(ContinuationHelper::return_address_at(
842 _cont_stack_top - frame::sender_sp_ret_address_offset()));
843 }
844
845 if (_monitors_in_lockstack > 0) {
846 freeze_lockstack(chunk);
847 }
848
849 _cont.write();
850
851 log_develop_trace(continuations)("FREEZE CHUNK #" INTPTR_FORMAT " (young)", _cont.hash());
852 LogTarget(Trace, continuations) lt;
853 if (lt.develop_is_enabled()) {
854 LogStream ls(lt);
855 chunk->print_on(true, &ls);
856 }
857
858 // Verification
859 assert(_cont.chunk_invariant(), "");
860 chunk->verify();
861
862 #if CONT_JFR
863 EventContinuationFreezeFast e;
864 if (e.should_commit()) {
865 e.set_id(cast_from_oop<u8>(chunk));
866 DEBUG_ONLY(e.set_allocate(chunk_is_allocated);)
867 e.set_size(cont_size() << LogBytesPerWord);
868 e.commit();
869 }
870 #endif
871 }
872
873 NOINLINE freeze_result FreezeBase::freeze_slow() {
874 #ifdef ASSERT
875 ResourceMark rm;
876 #endif
877
878 log_develop_trace(continuations)("freeze_slow #" INTPTR_FORMAT, _cont.hash());
879 assert(_thread->thread_state() == _thread_in_vm || _thread->thread_state() == _thread_blocked, "");
880
881 #if CONT_JFR
882 EventContinuationFreezeSlow e;
883 if (e.should_commit()) {
884 e.set_id(cast_from_oop<u8>(_cont.continuation()));
885 e.commit();
886 }
887 #endif
888
889 init_rest();
890
891 HandleMark hm(Thread::current());
892
893 frame f = freeze_start_frame();
894
895 LogTarget(Debug, continuations) lt;
896 if (lt.develop_is_enabled()) {
897 LogStream ls(lt);
898 f.print_on(&ls);
899 }
900
901 frame caller; // the frozen caller in the chunk
902 freeze_result res = recurse_freeze(f, caller, 0, false, true);
903
904 if (res == freeze_ok) {
905 finish_freeze(f, caller);
906 _cont.write();
907 }
908
909 return res;
910 }
911
912 frame FreezeBase::freeze_start_frame() {
913 if (LIKELY(!_preempt)) {
914 return freeze_start_frame_yield_stub();
915 } else {
916 return freeze_start_frame_on_preempt();
917 }
918 }
919
920 frame FreezeBase::freeze_start_frame_yield_stub() {
921 frame f = _thread->last_frame();
922 assert(SharedRuntime::cont_doYield_stub()->contains(f.pc()), "must be");
923 f = sender<ContinuationHelper::NonInterpretedUnknownFrame>(f);
924 assert(Continuation::is_frame_in_continuation(_thread->last_continuation(), f), "");
925 return f;
926 }
927
928 frame FreezeBase::freeze_start_frame_on_preempt() {
929 assert(_last_frame.sp() == _thread->last_frame().sp(), "_last_frame should be already initialized");
930 assert(Continuation::is_frame_in_continuation(_thread->last_continuation(), _last_frame), "");
931 return _last_frame;
932 }
933
934 // The parameter callee_argsize includes metadata that has to be part of caller/callee overlap.
935 NOINLINE freeze_result FreezeBase::recurse_freeze(frame& f, frame& caller, int callee_argsize, bool callee_interpreted, bool top) {
936 assert(f.unextended_sp() < _bottom_address, ""); // see recurse_freeze_java_frame
937 assert(f.is_interpreted_frame() || ((top && _preempt) == ContinuationHelper::Frame::is_stub(f.cb()))
938 || ((top && _preempt) == f.is_native_frame()), "");
939
940 if (stack_overflow()) {
941 return freeze_exception;
942 }
943
944 if (f.is_compiled_frame()) {
945 if (UNLIKELY(f.oop_map() == nullptr)) {
946 // special native frame
947 return freeze_pinned_native;
948 }
949 return recurse_freeze_compiled_frame(f, caller, callee_argsize, callee_interpreted);
950 } else if (f.is_interpreted_frame()) {
951 assert(!f.interpreter_frame_method()->is_native() || (top && _preempt), "");
952 return recurse_freeze_interpreted_frame(f, caller, callee_argsize, callee_interpreted);
953 } else if (top && _preempt) {
954 assert(f.is_native_frame() || f.is_runtime_frame(), "");
955 return f.is_native_frame() ? recurse_freeze_native_frame(f, caller) : recurse_freeze_stub_frame(f, caller);
956 } else {
957 // Frame can't be frozen. Most likely the call_stub or upcall_stub
958 // which indicates there are further natives frames up the stack.
959 return freeze_pinned_native;
960 }
961 }
962
963 // The parameter callee_argsize includes metadata that has to be part of caller/callee overlap.
964 // See also StackChunkFrameStream<frame_kind>::frame_size()
965 template<typename FKind>
966 inline freeze_result FreezeBase::recurse_freeze_java_frame(const frame& f, frame& caller, int fsize, int argsize) {
967 assert(FKind::is_instance(f), "");
968
969 assert(fsize > 0, "");
970 assert(argsize >= 0, "");
971 _freeze_size += fsize;
972 NOT_PRODUCT(_frames++;)
973
974 assert(FKind::frame_bottom(f) <= _bottom_address, "");
975
976 // We don't use FKind::frame_bottom(f) == _bottom_address because on x64 there's sometimes an extra word between
977 // enterSpecial and an interpreted frame
978 if (FKind::frame_bottom(f) >= _bottom_address - 1) {
979 return finalize_freeze(f, caller, argsize); // recursion end
980 } else {
981 frame senderf = sender<FKind>(f);
982 assert(FKind::interpreted || senderf.sp() == senderf.unextended_sp(), "");
983 freeze_result result = recurse_freeze(senderf, caller, argsize, FKind::interpreted, false); // recursive call
984 return result;
985 }
986 }
987
988 inline void FreezeBase::before_freeze_java_frame(const frame& f, const frame& caller, int fsize, int argsize, bool is_bottom_frame) {
989 LogTarget(Trace, continuations) lt;
990 if (lt.develop_is_enabled()) {
991 LogStream ls(lt);
992 ls.print_cr("======== FREEZING FRAME interpreted: %d bottom: %d", f.is_interpreted_frame(), is_bottom_frame);
993 ls.print_cr("fsize: %d argsize: %d", fsize, argsize);
994 f.print_value_on(&ls);
995 }
996 assert(caller.is_interpreted_frame() == Interpreter::contains(caller.pc()), "");
997 }
998
999 inline void FreezeBase::after_freeze_java_frame(const frame& hf, bool is_bottom_frame) {
1000 LogTarget(Trace, continuations) lt;
1001 if (lt.develop_is_enabled()) {
1002 LogStream ls(lt);
1003 DEBUG_ONLY(hf.print_value_on(&ls);)
1004 assert(hf.is_heap_frame(), "should be");
1005 DEBUG_ONLY(print_frame_layout(hf, false, &ls);)
1006 if (is_bottom_frame) {
1007 ls.print_cr("bottom h-frame:");
1008 hf.print_on(&ls);
1009 }
1010 }
1011 }
1012
1013 // The parameter argsize_md includes metadata that has to be part of caller/callee overlap.
1014 // See also StackChunkFrameStream<frame_kind>::frame_size()
1015 freeze_result FreezeBase::finalize_freeze(const frame& callee, frame& caller, int argsize_md) {
1016 int argsize = argsize_md - frame::metadata_words_at_top;
1017 assert(callee.is_interpreted_frame()
1018 || ContinuationHelper::Frame::is_stub(callee.cb())
1019 || callee.cb()->as_nmethod()->is_osr_method()
1020 || argsize == _cont.argsize(), "argsize: %d cont.argsize: %d", argsize, _cont.argsize());
1021 log_develop_trace(continuations)("bottom: " INTPTR_FORMAT " count %d size: %d argsize: %d",
1022 p2i(_bottom_address), _frames, _freeze_size << LogBytesPerWord, argsize);
1023
1024 LogTarget(Trace, continuations) lt;
1025
1026 #ifdef ASSERT
1027 bool empty = _cont.is_empty();
1028 log_develop_trace(continuations)("empty: %d", empty);
1029 #endif
1030
1031 stackChunkOop chunk = _cont.tail();
1032
1033 assert(chunk == nullptr || (chunk->max_thawing_size() == 0) == chunk->is_empty(), "");
1034
1035 _freeze_size += frame::metadata_words; // for top frame's metadata
1036
1037 int overlap = 0; // the args overlap the caller -- if there is one in this chunk and is of the same kind
1038 int unextended_sp = -1;
1039 if (chunk != nullptr) {
1040 if (!chunk->is_empty()) {
1041 StackChunkFrameStream<ChunkFrames::Mixed> last(chunk);
1042 unextended_sp = chunk->to_offset(StackChunkFrameStream<ChunkFrames::Mixed>(chunk).unextended_sp());
1043 bool top_interpreted = Interpreter::contains(chunk->pc());
1044 if (callee.is_interpreted_frame() == top_interpreted) {
1045 overlap = argsize_md;
1046 }
1047 } else {
1048 unextended_sp = chunk->stack_size() - frame::metadata_words_at_top;
1049 }
1050 }
1051
1052 log_develop_trace(continuations)("finalize _size: %d overlap: %d unextended_sp: %d", _freeze_size, overlap, unextended_sp);
1053
1054 _freeze_size -= overlap;
1055 assert(_freeze_size >= 0, "");
1056
1057 assert(chunk == nullptr || chunk->is_empty()
1058 || unextended_sp == chunk->to_offset(StackChunkFrameStream<ChunkFrames::Mixed>(chunk).unextended_sp()), "");
1059 assert(chunk != nullptr || unextended_sp < _freeze_size, "");
1060
1061 _freeze_size += _monitors_in_lockstack;
1062
1063 // _barriers can be set to true by an allocation in freeze_fast, in which case the chunk is available
1064 bool allocated_old_in_freeze_fast = _barriers;
1065 assert(!allocated_old_in_freeze_fast || (unextended_sp >= _freeze_size && chunk->is_empty()),
1066 "Chunk allocated in freeze_fast is of insufficient size "
1067 "unextended_sp: %d size: %d is_empty: %d", unextended_sp, _freeze_size, chunk->is_empty());
1068 assert(!allocated_old_in_freeze_fast || (!UseZGC && !UseG1GC), "Unexpected allocation");
1069
1070 DEBUG_ONLY(bool empty_chunk = true);
1071 if (unextended_sp < _freeze_size || chunk->is_gc_mode() || (!allocated_old_in_freeze_fast && chunk->requires_barriers())) {
1072 // ALLOCATE NEW CHUNK
1073
1074 if (lt.develop_is_enabled()) {
1075 LogStream ls(lt);
1076 if (chunk == nullptr) {
1077 ls.print_cr("no chunk");
1078 } else {
1079 ls.print_cr("chunk barriers: %d _size: %d free size: %d",
1080 chunk->requires_barriers(), _freeze_size, chunk->sp() - frame::metadata_words);
1081 chunk->print_on(&ls);
1082 }
1083 }
1084
1085 _freeze_size += overlap; // we're allocating a new chunk, so no overlap
1086 // overlap = 0;
1087
1088 chunk = allocate_chunk_slow(_freeze_size, argsize_md);
1089 if (chunk == nullptr) {
1090 return freeze_exception;
1091 }
1092
1093 // Install new chunk
1094 _cont.set_tail(chunk);
1095 assert(chunk->is_empty(), "");
1096 } else {
1097 // REUSE EXISTING CHUNK
1098 log_develop_trace(continuations)("Reusing chunk mixed: %d empty: %d", chunk->has_mixed_frames(), chunk->is_empty());
1099 if (chunk->is_empty()) {
1100 int sp = chunk->stack_size() - argsize_md;
1101 chunk->set_sp(sp);
1102 chunk->set_bottom(sp);
1103 _freeze_size += overlap;
1104 assert(chunk->max_thawing_size() == 0, "");
1105 } DEBUG_ONLY(else empty_chunk = false;)
1106 }
1107 assert(!chunk->is_gc_mode(), "");
1108 assert(!chunk->has_bitmap(), "");
1109 chunk->set_has_mixed_frames(true);
1110
1111 assert(chunk->requires_barriers() == _barriers, "");
1112 assert(!_barriers || chunk->is_empty(), "");
1113
1114 assert(!chunk->is_empty() || StackChunkFrameStream<ChunkFrames::Mixed>(chunk).is_done(), "");
1115 assert(!chunk->is_empty() || StackChunkFrameStream<ChunkFrames::Mixed>(chunk).to_frame().is_empty(), "");
1116
1117 if (_preempt) {
1118 frame f = _thread->last_frame();
1119 if (f.is_interpreted_frame()) {
1120 // Some platforms do not save the last_sp in the top interpreter frame on VM calls.
1121 // We need it so that on resume we can restore the sp to the right place, since
1122 // thawing might add an alignment word to the expression stack (see finish_thaw()).
1123 // We do it now that we know freezing will be successful.
1124 prepare_freeze_interpreted_top_frame(f);
1125 }
1126 }
1127
1128 // We unwind frames after the last safepoint so that the GC will have found the oops in the frames, but before
1129 // writing into the chunk. This is so that an asynchronous stack walk (not at a safepoint) that suspends us here
1130 // will either see no continuation or a consistent chunk.
1131 unwind_frames();
1132
1133 chunk->set_max_thawing_size(chunk->max_thawing_size() + _freeze_size - _monitors_in_lockstack - frame::metadata_words);
1134
1135 if (lt.develop_is_enabled()) {
1136 LogStream ls(lt);
1137 ls.print_cr("top chunk:");
1138 chunk->print_on(&ls);
1139 }
1140
1141 if (_monitors_in_lockstack > 0) {
1142 freeze_lockstack(chunk);
1143 }
1144
1145 // The topmost existing frame in the chunk; or an empty frame if the chunk is empty
1146 caller = StackChunkFrameStream<ChunkFrames::Mixed>(chunk).to_frame();
1147
1148 DEBUG_ONLY(_last_write = caller.unextended_sp() + (empty_chunk ? argsize_md : overlap);)
1149
1150 assert(chunk->is_in_chunk(_last_write - _freeze_size),
1151 "last_write-size: " INTPTR_FORMAT " start: " INTPTR_FORMAT, p2i(_last_write-_freeze_size), p2i(chunk->start_address()));
1152 #ifdef ASSERT
1153 if (lt.develop_is_enabled()) {
1154 LogStream ls(lt);
1155 ls.print_cr("top hframe before (freeze):");
1156 assert(caller.is_heap_frame(), "should be");
1157 caller.print_on(&ls);
1158 }
1159
1160 assert(!empty || Continuation::is_continuation_entry_frame(callee, nullptr), "");
1161
1162 frame entry = sender(callee);
1163
1164 assert((!empty && Continuation::is_return_barrier_entry(entry.pc())) || (empty && Continuation::is_continuation_enterSpecial(entry)), "");
1165 assert(callee.is_interpreted_frame() || entry.sp() == entry.unextended_sp(), "");
1166 #endif
1167
1168 return freeze_ok_bottom;
1169 }
1170
1171 // After freezing a frame we need to possibly adjust some values related to the caller frame.
1172 void FreezeBase::patch(const frame& f, frame& hf, const frame& caller, bool is_bottom_frame) {
1173 if (is_bottom_frame) {
1174 // If we're the bottom frame, we need to replace the return barrier with the real
1175 // caller's pc.
1176 address last_pc = caller.pc();
1177 assert((last_pc == nullptr) == _cont.tail()->is_empty(), "");
1178 ContinuationHelper::Frame::patch_pc(caller, last_pc);
1179 } else {
1180 assert(!caller.is_empty(), "");
1181 }
1182
1183 patch_pd(hf, caller);
1184
1185 if (f.is_interpreted_frame()) {
1186 assert(hf.is_heap_frame(), "should be");
1187 ContinuationHelper::InterpretedFrame::patch_sender_sp(hf, caller);
1188 }
1189
1190 #ifdef ASSERT
1191 if (hf.is_compiled_frame()) {
1192 if (f.is_deoptimized_frame()) { // TODO DEOPT: long term solution: unroll on freeze and patch pc
1193 log_develop_trace(continuations)("Freezing deoptimized frame");
1194 assert(f.cb()->as_nmethod()->is_deopt_pc(f.raw_pc()), "");
1195 assert(f.cb()->as_nmethod()->is_deopt_pc(ContinuationHelper::Frame::real_pc(f)), "");
1196 }
1197 }
1198 #endif
1199 }
1200
1201 #ifdef ASSERT
1202 static void verify_frame_top(const frame& f, intptr_t* top) {
1203 ResourceMark rm;
1204 InterpreterOopMap mask;
1205 f.interpreted_frame_oop_map(&mask);
1206 assert(top <= ContinuationHelper::InterpretedFrame::frame_top(f, &mask),
1207 "frame_top: " INTPTR_FORMAT " Interpreted::frame_top: " INTPTR_FORMAT,
1208 p2i(top), p2i(ContinuationHelper::InterpretedFrame::frame_top(f, &mask)));
1209 }
1210 #endif // ASSERT
1211
1212 // The parameter callee_argsize includes metadata that has to be part of caller/callee overlap.
1213 // See also StackChunkFrameStream<frame_kind>::frame_size()
1214 NOINLINE freeze_result FreezeBase::recurse_freeze_interpreted_frame(frame& f, frame& caller,
1215 int callee_argsize /* incl. metadata */,
1216 bool callee_interpreted) {
1217 adjust_interpreted_frame_unextended_sp(f);
1218
1219 // The frame's top never includes the stack arguments to the callee
1220 intptr_t* const stack_frame_top = ContinuationHelper::InterpretedFrame::frame_top(f, callee_argsize, callee_interpreted);
1221 intptr_t* const stack_frame_bottom = ContinuationHelper::InterpretedFrame::frame_bottom(f);
1222 const int fsize = pointer_delta_as_int(stack_frame_bottom, stack_frame_top);
1223
1224 DEBUG_ONLY(verify_frame_top(f, stack_frame_top));
1225
1226 Method* frame_method = ContinuationHelper::Frame::frame_method(f);
1227 // including metadata between f and its args
1228 const int argsize = ContinuationHelper::InterpretedFrame::stack_argsize(f) + frame::metadata_words_at_top;
1229
1230 log_develop_trace(continuations)("recurse_freeze_interpreted_frame %s _size: %d fsize: %d argsize: %d callee_interpreted: %d",
1231 frame_method->name_and_sig_as_C_string(), _freeze_size, fsize, argsize, callee_interpreted);
1232 // we'd rather not yield inside methods annotated with @JvmtiMountTransition
1233 assert(!ContinuationHelper::Frame::frame_method(f)->jvmti_mount_transition(), "");
1234
1235 freeze_result result = recurse_freeze_java_frame<ContinuationHelper::InterpretedFrame>(f, caller, fsize, argsize);
1236 if (UNLIKELY(result > freeze_ok_bottom)) {
1237 return result;
1238 }
1239
1240 bool is_bottom_frame = result == freeze_ok_bottom;
1241 assert(!caller.is_empty() || is_bottom_frame, "");
1242
1243 DEBUG_ONLY(before_freeze_java_frame(f, caller, fsize, 0, is_bottom_frame);)
1244
1245 frame hf = new_heap_frame<ContinuationHelper::InterpretedFrame>(f, caller);
1246 _total_align_size += frame::align_wiggle; // add alignment room for internal interpreted frame alignment on AArch64/PPC64
1247
1248 intptr_t* heap_frame_top = ContinuationHelper::InterpretedFrame::frame_top(hf, callee_argsize, callee_interpreted);
1249 intptr_t* heap_frame_bottom = ContinuationHelper::InterpretedFrame::frame_bottom(hf);
1250 assert(heap_frame_bottom == heap_frame_top + fsize, "");
1251
1252 // Some architectures (like AArch64/PPC64/RISC-V) add padding between the locals and the fixed_frame to keep the fp 16-byte-aligned.
1253 // On those architectures we freeze the padding in order to keep the same fp-relative offsets in the fixed_frame.
1254 copy_to_chunk(stack_frame_top, heap_frame_top, fsize);
1255 assert(!is_bottom_frame || !caller.is_interpreted_frame() || (heap_frame_top + fsize) == (caller.unextended_sp() + argsize), "");
1256
1257 relativize_interpreted_frame_metadata(f, hf);
1258
1259 patch(f, hf, caller, is_bottom_frame);
1260
1261 CONT_JFR_ONLY(_jfr_info.record_interpreted_frame();)
1262 DEBUG_ONLY(after_freeze_java_frame(hf, is_bottom_frame);)
1263 caller = hf;
1264
1265 // Mark frame_method's GC epoch for class redefinition on_stack calculation.
1266 frame_method->record_gc_epoch();
1267
1268 return freeze_ok;
1269 }
1270
1271 // The parameter callee_argsize includes metadata that has to be part of caller/callee overlap.
1272 // See also StackChunkFrameStream<frame_kind>::frame_size()
1273 freeze_result FreezeBase::recurse_freeze_compiled_frame(frame& f, frame& caller,
1274 int callee_argsize /* incl. metadata */,
1275 bool callee_interpreted) {
1276 // The frame's top never includes the stack arguments to the callee
1277 intptr_t* const stack_frame_top = ContinuationHelper::CompiledFrame::frame_top(f, callee_argsize, callee_interpreted);
1278 intptr_t* const stack_frame_bottom = ContinuationHelper::CompiledFrame::frame_bottom(f);
1279 // including metadata between f and its stackargs
1280 const int argsize = ContinuationHelper::CompiledFrame::stack_argsize(f) + frame::metadata_words_at_top;
1281 const int fsize = pointer_delta_as_int(stack_frame_bottom + argsize, stack_frame_top);
1282
1283 log_develop_trace(continuations)("recurse_freeze_compiled_frame %s _size: %d fsize: %d argsize: %d",
1284 ContinuationHelper::Frame::frame_method(f) != nullptr ?
1285 ContinuationHelper::Frame::frame_method(f)->name_and_sig_as_C_string() : "",
1286 _freeze_size, fsize, argsize);
1287 // we'd rather not yield inside methods annotated with @JvmtiMountTransition
1288 assert(!ContinuationHelper::Frame::frame_method(f)->jvmti_mount_transition(), "");
1289
1290 freeze_result result = recurse_freeze_java_frame<ContinuationHelper::CompiledFrame>(f, caller, fsize, argsize);
1291 if (UNLIKELY(result > freeze_ok_bottom)) {
1292 return result;
1293 }
1294
1295 bool is_bottom_frame = result == freeze_ok_bottom;
1296 assert(!caller.is_empty() || is_bottom_frame, "");
1297
1298 DEBUG_ONLY(before_freeze_java_frame(f, caller, fsize, argsize, is_bottom_frame);)
1299
1300 frame hf = new_heap_frame<ContinuationHelper::CompiledFrame>(f, caller);
1301
1302 intptr_t* heap_frame_top = ContinuationHelper::CompiledFrame::frame_top(hf, callee_argsize, callee_interpreted);
1303
1304 copy_to_chunk(stack_frame_top, heap_frame_top, fsize);
1305 assert(!is_bottom_frame || !caller.is_compiled_frame() || (heap_frame_top + fsize) == (caller.unextended_sp() + argsize), "");
1306
1307 if (caller.is_interpreted_frame()) {
1308 // When thawing the frame we might need to add alignment (see Thaw::align)
1309 _total_align_size += frame::align_wiggle;
1310 }
1311
1312 patch(f, hf, caller, is_bottom_frame);
1313
1314 assert(is_bottom_frame || Interpreter::contains(ContinuationHelper::CompiledFrame::real_pc(caller)) == caller.is_interpreted_frame(), "");
1315
1316 DEBUG_ONLY(after_freeze_java_frame(hf, is_bottom_frame);)
1317 caller = hf;
1318 return freeze_ok;
1319 }
1320
1321 NOINLINE freeze_result FreezeBase::recurse_freeze_stub_frame(frame& f, frame& caller) {
1322 DEBUG_ONLY(frame fsender = sender(f);)
1323 assert(fsender.is_compiled_frame(), "sender should be compiled frame");
1324
1325 intptr_t* const stack_frame_top = ContinuationHelper::StubFrame::frame_top(f);
1326 const int fsize = f.cb()->frame_size();
1327
1328 log_develop_trace(continuations)("recurse_freeze_stub_frame %s _size: %d fsize: %d :: " INTPTR_FORMAT " - " INTPTR_FORMAT,
1329 f.cb()->name(), _freeze_size, fsize, p2i(stack_frame_top), p2i(stack_frame_top+fsize));
1330
1331 freeze_result result = recurse_freeze_java_frame<ContinuationHelper::StubFrame>(f, caller, fsize, 0);
1332 if (UNLIKELY(result > freeze_ok_bottom)) {
1333 return result;
1334 }
1335
1336 assert(result == freeze_ok, "should have caller");
1337 DEBUG_ONLY(before_freeze_java_frame(f, caller, fsize, 0, false /*is_bottom_frame*/);)
1338
1339 frame hf = new_heap_frame<ContinuationHelper::StubFrame>(f, caller);
1340 intptr_t* heap_frame_top = ContinuationHelper::StubFrame::frame_top(hf);
1341
1342 copy_to_chunk(stack_frame_top, heap_frame_top, fsize);
1343
1344 patch(f, hf, caller, false /*is_bottom_frame*/);
1345
1346 DEBUG_ONLY(after_freeze_java_frame(hf, false /*is_bottom_frame*/);)
1347
1348 caller = hf;
1349 return freeze_ok;
1350 }
1351
1352 NOINLINE freeze_result FreezeBase::recurse_freeze_native_frame(frame& f, frame& caller) {
1353 if (!f.cb()->as_nmethod()->method()->is_object_wait0()) {
1354 assert(f.cb()->as_nmethod()->method()->is_synchronized(), "");
1355 // Synchronized native method case. Unlike the interpreter native wrapper, the compiled
1356 // native wrapper tries to acquire the monitor after marshalling the arguments from the
1357 // caller into the native convention. This is so that we have a valid oopMap in case of
1358 // having to block in the slow path. But that would require freezing those registers too
1359 // and then fixing them back on thaw in case of oops. To avoid complicating things and
1360 // given that this would be a rare case anyways just pin the vthread to the carrier.
1361 return freeze_pinned_native;
1362 }
1363
1364 intptr_t* const stack_frame_top = ContinuationHelper::NativeFrame::frame_top(f);
1365 // There are no stackargs but argsize must include the metadata
1366 const int argsize = frame::metadata_words_at_top;
1367 const int fsize = f.cb()->frame_size() + argsize;
1368
1369 log_develop_trace(continuations)("recurse_freeze_native_frame %s _size: %d fsize: %d :: " INTPTR_FORMAT " - " INTPTR_FORMAT,
1370 f.cb()->name(), _freeze_size, fsize, p2i(stack_frame_top), p2i(stack_frame_top+fsize));
1371
1372 freeze_result result = recurse_freeze_java_frame<ContinuationHelper::NativeFrame>(f, caller, fsize, argsize);
1373 if (UNLIKELY(result > freeze_ok_bottom)) {
1374 return result;
1375 }
1376
1377 assert(result == freeze_ok, "should have caller frame");
1378 DEBUG_ONLY(before_freeze_java_frame(f, caller, fsize, argsize, false /* is_bottom_frame */);)
1379
1380 frame hf = new_heap_frame<ContinuationHelper::NativeFrame>(f, caller);
1381 intptr_t* heap_frame_top = ContinuationHelper::NativeFrame::frame_top(hf);
1382
1383 copy_to_chunk(stack_frame_top, heap_frame_top, fsize);
1384
1385 if (caller.is_interpreted_frame()) {
1386 // When thawing the frame we might need to add alignment (see Thaw::align)
1387 _total_align_size += frame::align_wiggle;
1388 }
1389
1390 patch(f, hf, caller, false /* is_bottom_frame */);
1391
1392 DEBUG_ONLY(after_freeze_java_frame(hf, false /* is_bottom_frame */);)
1393
1394 caller = hf;
1395 return freeze_ok;
1396 }
1397
1398 NOINLINE void FreezeBase::finish_freeze(const frame& f, const frame& top) {
1399 stackChunkOop chunk = _cont.tail();
1400
1401 LogTarget(Trace, continuations) lt;
1402 if (lt.develop_is_enabled()) {
1403 LogStream ls(lt);
1404 assert(top.is_heap_frame(), "should be");
1405 top.print_on(&ls);
1406 }
1407
1408 set_top_frame_metadata_pd(top);
1409
1410 chunk->set_sp(chunk->to_offset(top.sp()));
1411 chunk->set_pc(top.pc());
1412
1413 chunk->set_max_thawing_size(chunk->max_thawing_size() + _total_align_size);
1414
1415 assert(chunk->sp_address() - chunk->start_address() >= _monitors_in_lockstack, "clash with lockstack");
1416
1417 // At this point the chunk is consistent
1418
1419 if (UNLIKELY(_barriers)) {
1420 log_develop_trace(continuations)("do barriers on old chunk");
1421 // Serial and Parallel GC can allocate objects directly into the old generation.
1422 // Then we want to relativize the derived pointers eagerly so that
1423 // old chunks are all in GC mode.
1424 assert(!UseG1GC, "G1 can not deal with allocating outside of eden");
1425 assert(!UseZGC, "ZGC can not deal with allocating chunks visible to marking");
1426 if (UseShenandoahGC) {
1427 _cont.tail()->relativize_derived_pointers_concurrently();
1428 } else {
1429 ContinuationGCSupport::transform_stack_chunk(_cont.tail());
1430 }
1431 // For objects in the old generation we must maintain the remembered set
1432 _cont.tail()->do_barriers<stackChunkOopDesc::BarrierType::Store>();
1433 }
1434
1435 log_develop_trace(continuations)("finish_freeze: has_mixed_frames: %d", chunk->has_mixed_frames());
1436 if (lt.develop_is_enabled()) {
1437 LogStream ls(lt);
1438 chunk->print_on(true, &ls);
1439 }
1440
1441 if (lt.develop_is_enabled()) {
1442 LogStream ls(lt);
1443 ls.print_cr("top hframe after (freeze):");
1444 assert(_cont.last_frame().is_heap_frame(), "should be");
1445 _cont.last_frame().print_on(&ls);
1446 DEBUG_ONLY(print_frame_layout(top, false, &ls);)
1447 }
1448
1449 assert(_cont.chunk_invariant(), "");
1450 }
1451
1452 inline bool FreezeBase::stack_overflow() { // detect stack overflow in recursive native code
1453 JavaThread* t = !_preempt ? _thread : JavaThread::current();
1454 assert(t == JavaThread::current(), "");
1455 if (os::current_stack_pointer() < t->stack_overflow_state()->shadow_zone_safe_limit()) {
1456 if (!_preempt) {
1457 ContinuationWrapper::SafepointOp so(t, _cont); // could also call _cont.done() instead
1458 Exceptions::_throw_msg(t, __FILE__, __LINE__, vmSymbols::java_lang_StackOverflowError(), "Stack overflow while freezing");
1459 }
1460 return true;
1461 }
1462 return false;
1463 }
1464
1465 class StackChunkAllocator : public MemAllocator {
1466 const size_t _stack_size;
1467 int _argsize_md;
1468 ContinuationWrapper& _continuation_wrapper;
1469 JvmtiSampledObjectAllocEventCollector* const _jvmti_event_collector;
1470 mutable bool _took_slow_path;
1471
1472 // Does the minimal amount of initialization needed for a TLAB allocation.
1473 // We don't need to do a full initialization, as such an allocation need not be immediately walkable.
1474 virtual oop initialize(HeapWord* mem) const override {
1475 assert(_stack_size > 0, "");
1476 assert(_stack_size <= max_jint, "");
1477 assert(_word_size > _stack_size, "");
1478
1479 // zero out fields (but not the stack)
1480 const size_t hs = oopDesc::header_size();
1481 if (oopDesc::has_klass_gap()) {
1482 oopDesc::set_klass_gap(mem, 0);
1483 }
1484 Copy::fill_to_aligned_words(mem + hs, vmClasses::StackChunk_klass()->size_helper() - hs);
1485
1486 int bottom = (int)_stack_size - _argsize_md;
1487
1488 jdk_internal_vm_StackChunk::set_size(mem, (int)_stack_size);
1489 jdk_internal_vm_StackChunk::set_bottom(mem, bottom);
1490 jdk_internal_vm_StackChunk::set_sp(mem, bottom);
1491
1492 return finish(mem);
1493 }
1494
1495 stackChunkOop allocate_fast() const {
1496 if (!UseTLAB) {
1497 return nullptr;
1498 }
1499
1500 HeapWord* const mem = MemAllocator::mem_allocate_inside_tlab_fast();
1501 if (mem == nullptr) {
1502 return nullptr;
1503 }
1504
1505 oop obj = initialize(mem);
1506 return stackChunkOopDesc::cast(obj);
1507 }
1508
1509 public:
1510 StackChunkAllocator(Klass* klass,
1511 size_t word_size,
1512 Thread* thread,
1513 size_t stack_size,
1514 int argsize_md,
1515 ContinuationWrapper& continuation_wrapper,
1516 JvmtiSampledObjectAllocEventCollector* jvmti_event_collector)
1517 : MemAllocator(klass, word_size, thread),
1518 _stack_size(stack_size),
1519 _argsize_md(argsize_md),
1520 _continuation_wrapper(continuation_wrapper),
1521 _jvmti_event_collector(jvmti_event_collector),
1522 _took_slow_path(false) {}
1523
1524 // Provides it's own, specialized allocation which skips instrumentation
1525 // if the memory can be allocated without going to a slow-path.
1526 stackChunkOop allocate() const {
1527 // First try to allocate without any slow-paths or instrumentation.
1528 stackChunkOop obj = allocate_fast();
1529 if (obj != nullptr) {
1530 return obj;
1531 }
1532
1533 // Now try full-blown allocation with all expensive operations,
1534 // including potentially safepoint operations.
1535 _took_slow_path = true;
1536
1537 // Protect unhandled Loom oops
1538 ContinuationWrapper::SafepointOp so(_thread, _continuation_wrapper);
1539
1540 // Can safepoint
1541 _jvmti_event_collector->start();
1542
1543 // Can safepoint
1544 return stackChunkOopDesc::cast(MemAllocator::allocate());
1545 }
1546
1547 bool took_slow_path() const {
1548 return _took_slow_path;
1549 }
1550 };
1551
1552 template <typename ConfigT>
1553 stackChunkOop Freeze<ConfigT>::allocate_chunk(size_t stack_size, int argsize_md) {
1554 log_develop_trace(continuations)("allocate_chunk allocating new chunk");
1555
1556 InstanceStackChunkKlass* klass = InstanceStackChunkKlass::cast(vmClasses::StackChunk_klass());
1557 size_t size_in_words = klass->instance_size(stack_size);
1558
1559 if (CollectedHeap::stack_chunk_max_size() > 0 && size_in_words >= CollectedHeap::stack_chunk_max_size()) {
1560 if (!_preempt) {
1561 throw_stack_overflow_on_humongous_chunk();
1562 }
1563 return nullptr;
1564 }
1565
1566 JavaThread* current = _preempt ? JavaThread::current() : _thread;
1567 assert(current == JavaThread::current(), "should be current");
1568
1569 // Allocate the chunk.
1570 //
1571 // This might safepoint while allocating, but all safepointing due to
1572 // instrumentation have been deferred. This property is important for
1573 // some GCs, as this ensures that the allocated object is in the young
1574 // generation / newly allocated memory.
1575 StackChunkAllocator allocator(klass, size_in_words, current, stack_size, argsize_md, _cont, _jvmti_event_collector);
1576 stackChunkOop chunk = allocator.allocate();
1577
1578 if (chunk == nullptr) {
1579 return nullptr; // OOME
1580 }
1581
1582 // assert that chunk is properly initialized
1583 assert(chunk->stack_size() == (int)stack_size, "");
1584 assert(chunk->size() >= stack_size, "chunk->size(): %zu size: %zu", chunk->size(), stack_size);
1585 assert(chunk->sp() == chunk->bottom(), "");
1586 assert((intptr_t)chunk->start_address() % 8 == 0, "");
1587 assert(chunk->max_thawing_size() == 0, "");
1588 assert(chunk->pc() == nullptr, "");
1589 assert(chunk->is_empty(), "");
1590 assert(chunk->flags() == 0, "");
1591 assert(chunk->is_gc_mode() == false, "");
1592 assert(chunk->lockstack_size() == 0, "");
1593
1594 // fields are uninitialized
1595 chunk->set_parent_access<IS_DEST_UNINITIALIZED>(_cont.last_nonempty_chunk());
1596 chunk->set_cont_access<IS_DEST_UNINITIALIZED>(_cont.continuation());
1597
1598 #if INCLUDE_ZGC
1599 if (UseZGC) {
1600 ZStackChunkGCData::initialize(chunk);
1601 assert(!chunk->requires_barriers(), "ZGC always allocates in the young generation");
1602 _barriers = false;
1603 } else
1604 #endif
1605 #if INCLUDE_SHENANDOAHGC
1606 if (UseShenandoahGC) {
1607 _barriers = chunk->requires_barriers();
1608 } else
1609 #endif
1610 {
1611 if (!allocator.took_slow_path()) {
1612 // Guaranteed to be in young gen / newly allocated memory
1613 assert(!chunk->requires_barriers(), "Unfamiliar GC requires barriers on TLAB allocation");
1614 _barriers = false;
1615 } else {
1616 // Some GCs could put direct allocations in old gen for slow-path
1617 // allocations; need to explicitly check if that was the case.
1618 _barriers = chunk->requires_barriers();
1619 }
1620 }
1621
1622 if (_barriers) {
1623 log_develop_trace(continuations)("allocation requires barriers");
1624 }
1625
1626 assert(chunk->parent() == nullptr || chunk->parent()->is_stackChunk(), "");
1627
1628 return chunk;
1629 }
1630
1631 void FreezeBase::throw_stack_overflow_on_humongous_chunk() {
1632 ContinuationWrapper::SafepointOp so(_thread, _cont); // could also call _cont.done() instead
1633 Exceptions::_throw_msg(_thread, __FILE__, __LINE__, vmSymbols::java_lang_StackOverflowError(), "Humongous stack chunk");
1634 }
1635
1636 #if INCLUDE_JVMTI
1637 static int num_java_frames(ContinuationWrapper& cont) {
1638 ResourceMark rm; // used for scope traversal in num_java_frames(nmethod*, address)
1639 int count = 0;
1640 for (stackChunkOop chunk = cont.tail(); chunk != nullptr; chunk = chunk->parent()) {
1641 count += chunk->num_java_frames();
1642 }
1643 return count;
1644 }
1645
1646 static void invalidate_jvmti_stack(JavaThread* thread) {
1647 if (thread->is_interp_only_mode()) {
1648 JvmtiThreadState *state = thread->jvmti_thread_state();
1649 if (state != nullptr)
1650 state->invalidate_cur_stack_depth();
1651 }
1652 }
1653
1654 static void jvmti_yield_cleanup(JavaThread* thread, ContinuationWrapper& cont) {
1655 if (JvmtiExport::can_post_frame_pop()) {
1656 int num_frames = num_java_frames(cont);
1657
1658 ContinuationWrapper::SafepointOp so(Thread::current(), cont);
1659 JvmtiExport::continuation_yield_cleanup(JavaThread::current(), num_frames);
1660 }
1661 invalidate_jvmti_stack(thread);
1662 }
1663
1664 static void jvmti_mount_end(JavaThread* current, ContinuationWrapper& cont, frame top) {
1665 assert(current->vthread() != nullptr, "must be");
1666
1667 HandleMarkCleaner hm(current);
1668 Handle vth(current, current->vthread());
1669
1670 ContinuationWrapper::SafepointOp so(current, cont);
1671
1672 // Since we might safepoint set the anchor so that the stack can be walked.
1673 set_anchor(current, top.sp());
1674
1675 JRT_BLOCK
1676 JvmtiVTMSTransitionDisabler::VTMS_vthread_mount((jthread)vth.raw_value(), false);
1677
1678 if (current->pending_contended_entered_event()) {
1679 JvmtiExport::post_monitor_contended_entered(current, current->contended_entered_monitor());
1680 current->set_contended_entered_monitor(nullptr);
1681 }
1682 JRT_BLOCK_END
1683
1684 clear_anchor(current);
1685 }
1686 #endif // INCLUDE_JVMTI
1687
1688 #ifdef ASSERT
1689 // There are no interpreted frames if we're not called from the interpreter and we haven't ancountered an i2c
1690 // adapter or called Deoptimization::unpack_frames. As for native frames, upcalls from JNI also go through the
1691 // interpreter (see JavaCalls::call_helper), while the UpcallLinker explicitly sets cont_fastpath.
1692 bool FreezeBase::check_valid_fast_path() {
1693 ContinuationEntry* ce = _thread->last_continuation();
1694 RegisterMap map(_thread,
1695 RegisterMap::UpdateMap::skip,
1696 RegisterMap::ProcessFrames::skip,
1697 RegisterMap::WalkContinuation::skip);
1698 map.set_include_argument_oops(false);
1699 bool is_top_frame = true;
1700 for (frame f = freeze_start_frame(); Continuation::is_frame_in_continuation(ce, f); f = f.sender(&map), is_top_frame = false) {
1701 if (!((f.is_compiled_frame() && !f.is_deoptimized_frame()) || (is_top_frame && (f.is_runtime_frame() || f.is_native_frame())))) {
1702 return false;
1703 }
1704 }
1705 return true;
1706 }
1707 #endif // ASSERT
1708
1709 static inline freeze_result freeze_epilog(ContinuationWrapper& cont) {
1710 verify_continuation(cont.continuation());
1711 assert(!cont.is_empty(), "");
1712
1713 log_develop_debug(continuations)("=== End of freeze cont ### #" INTPTR_FORMAT, cont.hash());
1714 return freeze_ok;
1715 }
1716
1717 static freeze_result freeze_epilog(JavaThread* thread, ContinuationWrapper& cont, freeze_result res) {
1718 if (UNLIKELY(res != freeze_ok)) {
1719 JFR_ONLY(thread->set_last_freeze_fail_result(res);)
1720 verify_continuation(cont.continuation());
1721 log_develop_trace(continuations)("=== end of freeze (fail %d)", res);
1722 return res;
1723 }
1724
1725 JVMTI_ONLY(jvmti_yield_cleanup(thread, cont)); // can safepoint
1726 return freeze_epilog(cont);
1727 }
1728
1729 static freeze_result preempt_epilog(ContinuationWrapper& cont, freeze_result res, frame& old_last_frame) {
1730 if (UNLIKELY(res != freeze_ok)) {
1731 verify_continuation(cont.continuation());
1732 log_develop_trace(continuations)("=== end of freeze (fail %d)", res);
1733 return res;
1734 }
1735
1736 patch_return_pc_with_preempt_stub(old_last_frame);
1737 cont.tail()->set_preempted(true);
1738
1739 return freeze_epilog(cont);
1740 }
1741
1742 template<typename ConfigT, bool preempt>
1743 static inline freeze_result freeze_internal(JavaThread* current, intptr_t* const sp) {
1744 assert(!current->has_pending_exception(), "");
1745
1746 #ifdef ASSERT
1747 log_trace(continuations)("~~~~ freeze sp: " INTPTR_FORMAT "JavaThread: " INTPTR_FORMAT, p2i(current->last_continuation()->entry_sp()), p2i(current));
1748 log_frames(current);
1749 #endif
1750
1751 CONT_JFR_ONLY(EventContinuationFreeze event;)
1752
1753 ContinuationEntry* entry = current->last_continuation();
1754
1755 oop oopCont = entry->cont_oop(current);
1756 assert(oopCont == current->last_continuation()->cont_oop(current), "");
1757 assert(ContinuationEntry::assert_entry_frame_laid_out(current), "");
1758
1759 verify_continuation(oopCont);
1760 ContinuationWrapper cont(current, oopCont);
1761 log_develop_debug(continuations)("FREEZE #" INTPTR_FORMAT " " INTPTR_FORMAT, cont.hash(), p2i((oopDesc*)oopCont));
1762
1763 assert(entry->is_virtual_thread() == (entry->scope(current) == java_lang_VirtualThread::vthread_scope()), "");
1764
1765 assert(LockingMode == LM_LEGACY || (current->held_monitor_count() == 0 && current->jni_monitor_count() == 0),
1766 "Held monitor count should only be used for LM_LEGACY: " INT64_FORMAT " JNI: " INT64_FORMAT, (int64_t)current->held_monitor_count(), (int64_t)current->jni_monitor_count());
1767
1768 if (entry->is_pinned() || current->held_monitor_count() > 0) {
1769 log_develop_debug(continuations)("PINNED due to critical section/hold monitor");
1770 verify_continuation(cont.continuation());
1771 freeze_result res = entry->is_pinned() ? freeze_pinned_cs : freeze_pinned_monitor;
1772 if (!preempt) {
1773 JFR_ONLY(current->set_last_freeze_fail_result(res);)
1774 }
1775 log_develop_trace(continuations)("=== end of freeze (fail %d)", res);
1776 // Avoid Thread.yield() loops without safepoint polls.
1777 if (SafepointMechanism::should_process(current) && !preempt) {
1778 cont.done(); // allow safepoint
1779 ThreadInVMfromJava tivmfj(current);
1780 }
1781 return res;
1782 }
1783
1784 Freeze<ConfigT> freeze(current, cont, sp, preempt);
1785
1786 assert(!current->cont_fastpath() || freeze.check_valid_fast_path(), "");
1787 bool fast = UseContinuationFastPath && current->cont_fastpath();
1788 if (fast && freeze.size_if_fast_freeze_available() > 0) {
1789 freeze.freeze_fast_existing_chunk();
1790 CONT_JFR_ONLY(freeze.jfr_info().post_jfr_event(&event, oopCont, current);)
1791 return !preempt ? freeze_epilog(cont) : preempt_epilog(cont, freeze_ok, freeze.last_frame());
1792 }
1793
1794 if (preempt) {
1795 JvmtiSampledObjectAllocEventCollector jsoaec(false);
1796 freeze.set_jvmti_event_collector(&jsoaec);
1797
1798 freeze_result res = fast ? freeze.try_freeze_fast() : freeze.freeze_slow();
1799
1800 CONT_JFR_ONLY(freeze.jfr_info().post_jfr_event(&event, oopCont, current);)
1801 preempt_epilog(cont, res, freeze.last_frame());
1802 return res;
1803 }
1804
1805 log_develop_trace(continuations)("chunk unavailable; transitioning to VM");
1806 assert(current == JavaThread::current(), "must be current thread");
1807 JRT_BLOCK
1808 // delays a possible JvmtiSampledObjectAllocEventCollector in alloc_chunk
1809 JvmtiSampledObjectAllocEventCollector jsoaec(false);
1810 freeze.set_jvmti_event_collector(&jsoaec);
1811
1812 freeze_result res = fast ? freeze.try_freeze_fast() : freeze.freeze_slow();
1813
1814 CONT_JFR_ONLY(freeze.jfr_info().post_jfr_event(&event, oopCont, current);)
1815 freeze_epilog(current, cont, res);
1816 cont.done(); // allow safepoint in the transition back to Java
1817 return res;
1818 JRT_BLOCK_END
1819 }
1820
1821 static freeze_result is_pinned0(JavaThread* thread, oop cont_scope, bool safepoint) {
1822 ContinuationEntry* entry = thread->last_continuation();
1823 if (entry == nullptr) {
1824 return freeze_ok;
1825 }
1826 if (entry->is_pinned()) {
1827 return freeze_pinned_cs;
1828 } else if (thread->held_monitor_count() > 0) {
1829 return freeze_pinned_monitor;
1830 }
1831
1832 RegisterMap map(thread,
1833 RegisterMap::UpdateMap::include,
1834 RegisterMap::ProcessFrames::skip,
1835 RegisterMap::WalkContinuation::skip);
1836 map.set_include_argument_oops(false);
1837 frame f = thread->last_frame();
1838
1839 if (!safepoint) {
1840 f = f.sender(&map); // this is the yield frame
1841 } else { // safepoint yield
1842 #if (defined(X86) || defined(AARCH64) || defined(RISCV64)) && !defined(ZERO)
1843 f.set_fp(f.real_fp()); // Instead of this, maybe in ContinuationWrapper::set_last_frame always use the real_fp?
1844 #else
1845 Unimplemented();
1846 #endif
1847 if (!Interpreter::contains(f.pc())) {
1848 assert(ContinuationHelper::Frame::is_stub(f.cb()), "must be");
1849 assert(f.oop_map() != nullptr, "must be");
1850 f.oop_map()->update_register_map(&f, &map); // we have callee-save registers in this case
1851 }
1852 }
1853
1854 while (true) {
1855 if ((f.is_interpreted_frame() && f.interpreter_frame_method()->is_native()) || f.is_native_frame()) {
1856 return freeze_pinned_native;
1857 }
1858
1859 f = f.sender(&map);
1860 if (!Continuation::is_frame_in_continuation(entry, f)) {
1861 oop scope = jdk_internal_vm_Continuation::scope(entry->cont_oop(thread));
1862 if (scope == cont_scope) {
1863 break;
1864 }
1865 intx monitor_count = entry->parent_held_monitor_count();
1866 entry = entry->parent();
1867 if (entry == nullptr) {
1868 break;
1869 }
1870 if (entry->is_pinned()) {
1871 return freeze_pinned_cs;
1872 } else if (monitor_count > 0) {
1873 return freeze_pinned_monitor;
1874 }
1875 }
1876 }
1877 return freeze_ok;
1878 }
1879
1880 /////////////// THAW ////
1881
1882 static int thaw_size(stackChunkOop chunk) {
1883 int size = chunk->max_thawing_size();
1884 size += frame::metadata_words; // For the top pc+fp in push_return_frame or top = stack_sp - frame::metadata_words in thaw_fast
1885 size += 2*frame::align_wiggle; // in case of alignments at the top and bottom
1886 return size;
1887 }
1888
1889 // make room on the stack for thaw
1890 // returns the size in bytes, or 0 on failure
1891 static inline int prepare_thaw_internal(JavaThread* thread, bool return_barrier) {
1892 log_develop_trace(continuations)("~~~~ prepare_thaw return_barrier: %d", return_barrier);
1893
1894 assert(thread == JavaThread::current(), "");
1895
1896 ContinuationEntry* ce = thread->last_continuation();
1897 assert(ce != nullptr, "");
1898 oop continuation = ce->cont_oop(thread);
1899 assert(continuation == get_continuation(thread), "");
1900 verify_continuation(continuation);
1901
1902 stackChunkOop chunk = jdk_internal_vm_Continuation::tail(continuation);
1903 assert(chunk != nullptr, "");
1904
1905 // The tail can be empty because it might still be available for another freeze.
1906 // However, here we want to thaw, so we get rid of it (it will be GCed).
1907 if (UNLIKELY(chunk->is_empty())) {
1908 chunk = chunk->parent();
1909 assert(chunk != nullptr, "");
1910 assert(!chunk->is_empty(), "");
1911 jdk_internal_vm_Continuation::set_tail(continuation, chunk);
1912 }
1913
1914 // Verification
1915 chunk->verify();
1916 assert(chunk->max_thawing_size() > 0, "chunk invariant violated; expected to not be empty");
1917
1918 // Only make space for the last chunk because we only thaw from the last chunk
1919 int size = thaw_size(chunk) << LogBytesPerWord;
1920
1921 const address bottom = (address)thread->last_continuation()->entry_sp();
1922 // 300 is an estimate for stack size taken for this native code, in addition to StackShadowPages
1923 // for the Java frames in the check below.
1924 if (!stack_overflow_check(thread, size + 300, bottom)) {
1925 return 0;
1926 }
1927
1928 log_develop_trace(continuations)("prepare_thaw bottom: " INTPTR_FORMAT " top: " INTPTR_FORMAT " size: %d",
1929 p2i(bottom), p2i(bottom - size), size);
1930 return size;
1931 }
1932
1933 class ThawBase : public StackObj {
1934 protected:
1935 JavaThread* _thread;
1936 ContinuationWrapper& _cont;
1937 CONT_JFR_ONLY(FreezeThawJfrInfo _jfr_info;)
1938
1939 intptr_t* _fastpath;
1940 bool _barriers;
1941 bool _preempted_case;
1942 intptr_t* _top_unextended_sp_before_thaw;
1943 int _align_size;
1944 DEBUG_ONLY(intptr_t* _top_stack_address);
1945
1946 StackChunkFrameStream<ChunkFrames::Mixed> _stream;
1947
1948 NOT_PRODUCT(int _frames;)
1949
1950 protected:
1951 ThawBase(JavaThread* thread, ContinuationWrapper& cont) :
1952 _thread(thread), _cont(cont),
1953 _fastpath(nullptr) {
1954 DEBUG_ONLY(_top_unextended_sp_before_thaw = nullptr;)
1955 assert (cont.tail() != nullptr, "no last chunk");
1956 DEBUG_ONLY(_top_stack_address = _cont.entrySP() - thaw_size(cont.tail());)
1957 }
1958
1959 void clear_chunk(stackChunkOop chunk);
1960 template<bool check_stub>
1961 int remove_top_compiled_frame_from_chunk(stackChunkOop chunk, int &argsize);
1962 void copy_from_chunk(intptr_t* from, intptr_t* to, int size);
1963
1964 void thaw_lockstack(stackChunkOop chunk);
1965
1966 // fast path
1967 inline void prefetch_chunk_pd(void* start, int size_words);
1968 void patch_return(intptr_t* sp, bool is_last);
1969
1970 intptr_t* handle_preempted_continuation(intptr_t* sp, Continuation::preempt_kind preempt_kind, bool fast_case);
1971 inline intptr_t* push_cleanup_continuation();
1972 void throw_interrupted_exception(JavaThread* current, frame& top);
1973
1974 void recurse_thaw(const frame& heap_frame, frame& caller, int num_frames, bool top_on_preempt_case);
1975 void finish_thaw(frame& f);
1976
1977 private:
1978 template<typename FKind> bool recurse_thaw_java_frame(frame& caller, int num_frames);
1979 void finalize_thaw(frame& entry, int argsize);
1980
1981 inline bool seen_by_gc();
1982
1983 inline void before_thaw_java_frame(const frame& hf, const frame& caller, bool bottom, int num_frame);
1984 inline void after_thaw_java_frame(const frame& f, bool bottom);
1985 inline void patch(frame& f, const frame& caller, bool bottom);
1986 void clear_bitmap_bits(address start, address end);
1987
1988 NOINLINE void recurse_thaw_interpreted_frame(const frame& hf, frame& caller, int num_frames);
1989 void recurse_thaw_compiled_frame(const frame& hf, frame& caller, int num_frames, bool stub_caller);
1990 void recurse_thaw_stub_frame(const frame& hf, frame& caller, int num_frames);
1991 void recurse_thaw_native_frame(const frame& hf, frame& caller, int num_frames);
1992
1993 void push_return_frame(frame& f);
1994 inline frame new_entry_frame();
1995 template<typename FKind> frame new_stack_frame(const frame& hf, frame& caller, bool bottom);
1996 inline void patch_pd(frame& f, const frame& sender);
1997 inline void patch_pd(frame& f, intptr_t* caller_sp);
1998 inline intptr_t* align(const frame& hf, intptr_t* frame_sp, frame& caller, bool bottom);
1999
2000 void maybe_set_fastpath(intptr_t* sp) { if (sp > _fastpath) _fastpath = sp; }
2001
2002 static inline void derelativize_interpreted_frame_metadata(const frame& hf, const frame& f);
2003
2004 public:
2005 CONT_JFR_ONLY(FreezeThawJfrInfo& jfr_info() { return _jfr_info; })
2006 };
2007
2008 template <typename ConfigT>
2009 class Thaw : public ThawBase {
2010 public:
2011 Thaw(JavaThread* thread, ContinuationWrapper& cont) : ThawBase(thread, cont) {}
2012
2013 inline bool can_thaw_fast(stackChunkOop chunk) {
2014 return !_barriers
2015 && _thread->cont_fastpath_thread_state()
2016 && !chunk->has_thaw_slowpath_condition()
2017 && !PreserveFramePointer;
2018 }
2019
2020 inline intptr_t* thaw(Continuation::thaw_kind kind);
2021 template<bool check_stub = false>
2022 NOINLINE intptr_t* thaw_fast(stackChunkOop chunk);
2023 NOINLINE intptr_t* thaw_slow(stackChunkOop chunk, Continuation::thaw_kind kind);
2024 inline void patch_caller_links(intptr_t* sp, intptr_t* bottom);
2025 };
2026
2027 template <typename ConfigT>
2028 inline intptr_t* Thaw<ConfigT>::thaw(Continuation::thaw_kind kind) {
2029 verify_continuation(_cont.continuation());
2030 assert(!jdk_internal_vm_Continuation::done(_cont.continuation()), "");
2031 assert(!_cont.is_empty(), "");
2032
2033 stackChunkOop chunk = _cont.tail();
2034 assert(chunk != nullptr, "guaranteed by prepare_thaw");
2035 assert(!chunk->is_empty(), "guaranteed by prepare_thaw");
2036
2037 _barriers = chunk->requires_barriers();
2038 return (LIKELY(can_thaw_fast(chunk))) ? thaw_fast(chunk)
2039 : thaw_slow(chunk, kind);
2040 }
2041
2042 class ReconstructedStack : public StackObj {
2043 intptr_t* _base; // _cont.entrySP(); // top of the entry frame
2044 int _thaw_size;
2045 int _argsize;
2046 public:
2047 ReconstructedStack(intptr_t* base, int thaw_size, int argsize)
2048 : _base(base), _thaw_size(thaw_size - (argsize == 0 ? frame::metadata_words_at_top : 0)), _argsize(argsize) {
2049 // The only possible source of misalignment is stack-passed arguments b/c compiled frames are 16-byte aligned.
2050 assert(argsize != 0 || (_base - _thaw_size) == ContinuationHelper::frame_align_pointer(_base - _thaw_size), "");
2051 // We're at most one alignment word away from entrySP
2052 assert(_base - 1 <= top() + total_size() + frame::metadata_words_at_bottom, "missed entry frame");
2053 }
2054
2055 int entry_frame_extension() const { return _argsize + (_argsize > 0 ? frame::metadata_words_at_top : 0); }
2056
2057 // top and bottom stack pointers
2058 intptr_t* sp() const { return ContinuationHelper::frame_align_pointer(_base - _thaw_size); }
2059 intptr_t* bottom_sp() const { return ContinuationHelper::frame_align_pointer(_base - entry_frame_extension()); }
2060
2061 // several operations operate on the totality of the stack being reconstructed,
2062 // including the metadata words
2063 intptr_t* top() const { return sp() - frame::metadata_words_at_bottom; }
2064 int total_size() const { return _thaw_size + frame::metadata_words_at_bottom; }
2065 };
2066
2067 inline void ThawBase::clear_chunk(stackChunkOop chunk) {
2068 chunk->set_sp(chunk->bottom());
2069 chunk->set_max_thawing_size(0);
2070 }
2071
2072 template<bool check_stub>
2073 int ThawBase::remove_top_compiled_frame_from_chunk(stackChunkOop chunk, int &argsize) {
2074 bool empty = false;
2075 StackChunkFrameStream<ChunkFrames::CompiledOnly> f(chunk);
2076 DEBUG_ONLY(intptr_t* const chunk_sp = chunk->start_address() + chunk->sp();)
2077 assert(chunk_sp == f.sp(), "");
2078 assert(chunk_sp == f.unextended_sp(), "");
2079
2080 int frame_size = f.cb()->frame_size();
2081 argsize = f.stack_argsize();
2082
2083 assert(!f.is_stub() || check_stub, "");
2084 if (check_stub && f.is_stub()) {
2085 // If we don't thaw the top compiled frame too, after restoring the saved
2086 // registers back in Java, we would hit the return barrier to thaw one more
2087 // frame effectively overwriting the restored registers during that call.
2088 f.next(SmallRegisterMap::instance(), true /* stop */);
2089 assert(!f.is_done(), "");
2090
2091 f.get_cb();
2092 assert(f.is_compiled(), "");
2093 frame_size += f.cb()->frame_size();
2094 argsize = f.stack_argsize();
2095
2096 if (f.cb()->as_nmethod()->is_marked_for_deoptimization()) {
2097 // The caller of the runtime stub when the continuation is preempted is not at a
2098 // Java call instruction, and so cannot rely on nmethod patching for deopt.
2099 log_develop_trace(continuations)("Deoptimizing runtime stub caller");
2100 f.to_frame().deoptimize(nullptr); // the null thread simply avoids the assertion in deoptimize which we're not set up for
2101 }
2102 }
2103
2104 f.next(SmallRegisterMap::instance(), true /* stop */);
2105 empty = f.is_done();
2106 assert(!empty || argsize == chunk->argsize(), "");
2107
2108 if (empty) {
2109 clear_chunk(chunk);
2110 } else {
2111 chunk->set_sp(chunk->sp() + frame_size);
2112 chunk->set_max_thawing_size(chunk->max_thawing_size() - frame_size);
2113 // We set chunk->pc to the return pc into the next frame
2114 chunk->set_pc(f.pc());
2115 #ifdef ASSERT
2116 {
2117 intptr_t* retaddr_slot = (chunk_sp
2118 + frame_size
2119 - frame::sender_sp_ret_address_offset());
2120 assert(f.pc() == ContinuationHelper::return_address_at(retaddr_slot),
2121 "unexpected pc");
2122 }
2123 #endif
2124 }
2125 assert(empty == chunk->is_empty(), "");
2126 // returns the size required to store the frame on stack, and because it is a
2127 // compiled frame, it must include a copy of the arguments passed by the caller
2128 return frame_size + argsize + frame::metadata_words_at_top;
2129 }
2130
2131 void ThawBase::thaw_lockstack(stackChunkOop chunk) {
2132 int lockStackSize = chunk->lockstack_size();
2133 assert(lockStackSize > 0 && lockStackSize <= LockStack::CAPACITY, "");
2134
2135 oop tmp_lockstack[LockStack::CAPACITY];
2136 chunk->transfer_lockstack(tmp_lockstack, _barriers);
2137 _thread->lock_stack().move_from_address(tmp_lockstack, lockStackSize);
2138
2139 chunk->set_lockstack_size(0);
2140 chunk->set_has_lockstack(false);
2141 }
2142
2143 void ThawBase::copy_from_chunk(intptr_t* from, intptr_t* to, int size) {
2144 assert(to >= _top_stack_address, "overwrote past thawing space"
2145 " to: " INTPTR_FORMAT " top_address: " INTPTR_FORMAT, p2i(to), p2i(_top_stack_address));
2146 assert(to + size <= _cont.entrySP(), "overwrote past thawing space");
2147 _cont.tail()->copy_from_chunk_to_stack(from, to, size);
2148 CONT_JFR_ONLY(_jfr_info.record_size_copied(size);)
2149 }
2150
2151 void ThawBase::patch_return(intptr_t* sp, bool is_last) {
2152 log_develop_trace(continuations)("thaw_fast patching -- sp: " INTPTR_FORMAT, p2i(sp));
2153
2154 address pc = !is_last ? StubRoutines::cont_returnBarrier() : _cont.entryPC();
2155 ContinuationHelper::patch_return_address_at(
2156 sp - frame::sender_sp_ret_address_offset(),
2157 pc);
2158 }
2159
2160 template <typename ConfigT>
2161 template<bool check_stub>
2162 NOINLINE intptr_t* Thaw<ConfigT>::thaw_fast(stackChunkOop chunk) {
2163 assert(chunk == _cont.tail(), "");
2164 assert(!chunk->has_mixed_frames(), "");
2165 assert(!chunk->requires_barriers(), "");
2166 assert(!chunk->has_bitmap(), "");
2167 assert(!_thread->is_interp_only_mode(), "");
2168
2169 LogTarget(Trace, continuations) lt;
2170 if (lt.develop_is_enabled()) {
2171 LogStream ls(lt);
2172 ls.print_cr("thaw_fast");
2173 chunk->print_on(true, &ls);
2174 }
2175
2176 // Below this heuristic, we thaw the whole chunk, above it we thaw just one frame.
2177 static const int threshold = 500; // words
2178
2179 const int full_chunk_size = chunk->stack_size() - chunk->sp(); // this initial size could be reduced if it's a partial thaw
2180 int argsize, thaw_size;
2181
2182 intptr_t* const chunk_sp = chunk->start_address() + chunk->sp();
2183
2184 bool partial, empty;
2185 if (LIKELY(!TEST_THAW_ONE_CHUNK_FRAME && (full_chunk_size < threshold))) {
2186 prefetch_chunk_pd(chunk->start_address(), full_chunk_size); // prefetch anticipating memcpy starting at highest address
2187
2188 partial = false;
2189 argsize = chunk->argsize(); // must be called *before* clearing the chunk
2190 clear_chunk(chunk);
2191 thaw_size = full_chunk_size;
2192 empty = true;
2193 } else { // thaw a single frame
2194 partial = true;
2195 thaw_size = remove_top_compiled_frame_from_chunk<check_stub>(chunk, argsize);
2196 empty = chunk->is_empty();
2197 }
2198
2199 // Are we thawing the last frame(s) in the continuation
2200 const bool is_last = empty && chunk->parent() == nullptr;
2201 assert(!is_last || argsize == 0, "");
2202
2203 log_develop_trace(continuations)("thaw_fast partial: %d is_last: %d empty: %d size: %d argsize: %d entrySP: " PTR_FORMAT,
2204 partial, is_last, empty, thaw_size, argsize, p2i(_cont.entrySP()));
2205
2206 ReconstructedStack rs(_cont.entrySP(), thaw_size, argsize);
2207
2208 // also copy metadata words at frame bottom
2209 copy_from_chunk(chunk_sp - frame::metadata_words_at_bottom, rs.top(), rs.total_size());
2210
2211 // update the ContinuationEntry
2212 _cont.set_argsize(argsize);
2213 log_develop_trace(continuations)("setting entry argsize: %d", _cont.argsize());
2214 assert(rs.bottom_sp() == _cont.entry()->bottom_sender_sp(), "");
2215
2216 // install the return barrier if not last frame, or the entry's pc if last
2217 patch_return(rs.bottom_sp(), is_last);
2218
2219 // insert the back links from callee to caller frames
2220 patch_caller_links(rs.top(), rs.top() + rs.total_size());
2221
2222 assert(is_last == _cont.is_empty(), "");
2223 assert(_cont.chunk_invariant(), "");
2224
2225 #if CONT_JFR
2226 EventContinuationThawFast e;
2227 if (e.should_commit()) {
2228 e.set_id(cast_from_oop<u8>(chunk));
2229 e.set_size(thaw_size << LogBytesPerWord);
2230 e.set_full(!partial);
2231 e.commit();
2232 }
2233 #endif
2234
2235 #ifdef ASSERT
2236 set_anchor(_thread, rs.sp());
2237 log_frames(_thread);
2238 if (LoomDeoptAfterThaw) {
2239 do_deopt_after_thaw(_thread);
2240 }
2241 clear_anchor(_thread);
2242 #endif
2243
2244 return rs.sp();
2245 }
2246
2247 inline bool ThawBase::seen_by_gc() {
2248 return _barriers || _cont.tail()->is_gc_mode();
2249 }
2250
2251 static inline void relativize_chunk_concurrently(stackChunkOop chunk) {
2252 #if INCLUDE_ZGC || INCLUDE_SHENANDOAHGC
2253 if (UseZGC || UseShenandoahGC) {
2254 chunk->relativize_derived_pointers_concurrently();
2255 }
2256 #endif
2257 }
2258
2259 template <typename ConfigT>
2260 NOINLINE intptr_t* Thaw<ConfigT>::thaw_slow(stackChunkOop chunk, Continuation::thaw_kind kind) {
2261 Continuation::preempt_kind preempt_kind;
2262 bool retry_fast_path = false;
2263
2264 _preempted_case = chunk->preempted();
2265 if (_preempted_case) {
2266 ObjectWaiter* waiter = java_lang_VirtualThread::objectWaiter(_thread->vthread());
2267 if (waiter != nullptr) {
2268 // Mounted again after preemption. Resume the pending monitor operation,
2269 // which will be either a monitorenter or Object.wait() call.
2270 ObjectMonitor* mon = waiter->monitor();
2271 preempt_kind = waiter->is_wait() ? Continuation::freeze_on_wait : Continuation::freeze_on_monitorenter;
2272
2273 bool mon_acquired = mon->resume_operation(_thread, waiter, _cont);
2274 assert(!mon_acquired || mon->has_owner(_thread), "invariant");
2275 if (!mon_acquired) {
2276 // Failed to acquire monitor. Return to enterSpecial to unmount again.
2277 return push_cleanup_continuation();
2278 }
2279 chunk = _cont.tail(); // reload oop in case of safepoint in resume_operation (if posting JVMTI events).
2280 } else {
2281 // Preemption cancelled in moniterenter case. We actually acquired
2282 // the monitor after freezing all frames so nothing to do.
2283 preempt_kind = Continuation::freeze_on_monitorenter;
2284 }
2285 // Call this first to avoid racing with GC threads later when modifying the chunk flags.
2286 relativize_chunk_concurrently(chunk);
2287 chunk->set_preempted(false);
2288 retry_fast_path = true;
2289 } else {
2290 relativize_chunk_concurrently(chunk);
2291 }
2292
2293 // On first thaw after freeze restore oops to the lockstack if any.
2294 assert(chunk->lockstack_size() == 0 || kind == Continuation::thaw_top, "");
2295 if (kind == Continuation::thaw_top && chunk->lockstack_size() > 0) {
2296 thaw_lockstack(chunk);
2297 retry_fast_path = true;
2298 }
2299
2300 // Retry the fast path now that we possibly cleared the FLAG_HAS_LOCKSTACK
2301 // and FLAG_PREEMPTED flags from the stackChunk.
2302 if (retry_fast_path && can_thaw_fast(chunk)) {
2303 intptr_t* sp = thaw_fast<true>(chunk);
2304 if (_preempted_case) {
2305 return handle_preempted_continuation(sp, preempt_kind, true /* fast_case */);
2306 }
2307 return sp;
2308 }
2309
2310 LogTarget(Trace, continuations) lt;
2311 if (lt.develop_is_enabled()) {
2312 LogStream ls(lt);
2313 ls.print_cr("thaw slow return_barrier: %d " INTPTR_FORMAT, kind, p2i(chunk));
2314 chunk->print_on(true, &ls);
2315 }
2316
2317 #if CONT_JFR
2318 EventContinuationThawSlow e;
2319 if (e.should_commit()) {
2320 e.set_id(cast_from_oop<u8>(_cont.continuation()));
2321 e.commit();
2322 }
2323 #endif
2324
2325 DEBUG_ONLY(_frames = 0;)
2326 _align_size = 0;
2327 int num_frames = kind == Continuation::thaw_top ? 2 : 1;
2328
2329 _stream = StackChunkFrameStream<ChunkFrames::Mixed>(chunk);
2330 _top_unextended_sp_before_thaw = _stream.unextended_sp();
2331
2332 frame heap_frame = _stream.to_frame();
2333 if (lt.develop_is_enabled()) {
2334 LogStream ls(lt);
2335 ls.print_cr("top hframe before (thaw):");
2336 assert(heap_frame.is_heap_frame(), "should have created a relative frame");
2337 heap_frame.print_value_on(&ls);
2338 }
2339
2340 frame caller; // the thawed caller on the stack
2341 recurse_thaw(heap_frame, caller, num_frames, _preempted_case);
2342 finish_thaw(caller); // caller is now the topmost thawed frame
2343 _cont.write();
2344
2345 assert(_cont.chunk_invariant(), "");
2346
2347 JVMTI_ONLY(invalidate_jvmti_stack(_thread));
2348
2349 _thread->set_cont_fastpath(_fastpath);
2350
2351 intptr_t* sp = caller.sp();
2352
2353 if (_preempted_case) {
2354 return handle_preempted_continuation(sp, preempt_kind, false /* fast_case */);
2355 }
2356 return sp;
2357 }
2358
2359 void ThawBase::recurse_thaw(const frame& heap_frame, frame& caller, int num_frames, bool top_on_preempt_case) {
2360 log_develop_debug(continuations)("thaw num_frames: %d", num_frames);
2361 assert(!_cont.is_empty(), "no more frames");
2362 assert(num_frames > 0, "");
2363 assert(!heap_frame.is_empty(), "");
2364
2365 if (top_on_preempt_case && (heap_frame.is_native_frame() || heap_frame.is_runtime_frame())) {
2366 heap_frame.is_native_frame() ? recurse_thaw_native_frame(heap_frame, caller, 2) : recurse_thaw_stub_frame(heap_frame, caller, 2);
2367 } else if (!heap_frame.is_interpreted_frame()) {
2368 recurse_thaw_compiled_frame(heap_frame, caller, num_frames, false);
2369 } else {
2370 recurse_thaw_interpreted_frame(heap_frame, caller, num_frames);
2371 }
2372 }
2373
2374 template<typename FKind>
2375 bool ThawBase::recurse_thaw_java_frame(frame& caller, int num_frames) {
2376 assert(num_frames > 0, "");
2377
2378 DEBUG_ONLY(_frames++;)
2379
2380 int argsize = _stream.stack_argsize();
2381
2382 _stream.next(SmallRegisterMap::instance());
2383 assert(_stream.to_frame().is_empty() == _stream.is_done(), "");
2384
2385 // we never leave a compiled caller of an interpreted frame as the top frame in the chunk
2386 // as it makes detecting that situation and adjusting unextended_sp tricky
2387 if (num_frames == 1 && !_stream.is_done() && FKind::interpreted && _stream.is_compiled()) {
2388 log_develop_trace(continuations)("thawing extra compiled frame to not leave a compiled interpreted-caller at top");
2389 num_frames++;
2390 }
2391
2392 if (num_frames == 1 || _stream.is_done()) { // end recursion
2393 finalize_thaw(caller, FKind::interpreted ? 0 : argsize);
2394 return true; // bottom
2395 } else { // recurse
2396 recurse_thaw(_stream.to_frame(), caller, num_frames - 1, false /* top_on_preempt_case */);
2397 return false;
2398 }
2399 }
2400
2401 void ThawBase::finalize_thaw(frame& entry, int argsize) {
2402 stackChunkOop chunk = _cont.tail();
2403
2404 if (!_stream.is_done()) {
2405 assert(_stream.sp() >= chunk->sp_address(), "");
2406 chunk->set_sp(chunk->to_offset(_stream.sp()));
2407 chunk->set_pc(_stream.pc());
2408 } else {
2409 chunk->set_sp(chunk->bottom());
2410 chunk->set_pc(nullptr);
2411 }
2412 assert(_stream.is_done() == chunk->is_empty(), "");
2413
2414 int total_thawed = pointer_delta_as_int(_stream.unextended_sp(), _top_unextended_sp_before_thaw);
2415 chunk->set_max_thawing_size(chunk->max_thawing_size() - total_thawed);
2416
2417 _cont.set_argsize(argsize);
2418 entry = new_entry_frame();
2419
2420 assert(entry.sp() == _cont.entrySP(), "");
2421 assert(Continuation::is_continuation_enterSpecial(entry), "");
2422 assert(_cont.is_entry_frame(entry), "");
2423 }
2424
2425 inline void ThawBase::before_thaw_java_frame(const frame& hf, const frame& caller, bool bottom, int num_frame) {
2426 LogTarget(Trace, continuations) lt;
2427 if (lt.develop_is_enabled()) {
2428 LogStream ls(lt);
2429 ls.print_cr("======== THAWING FRAME: %d", num_frame);
2430 assert(hf.is_heap_frame(), "should be");
2431 hf.print_value_on(&ls);
2432 }
2433 assert(bottom == _cont.is_entry_frame(caller), "bottom: %d is_entry_frame: %d", bottom, _cont.is_entry_frame(hf));
2434 }
2435
2436 inline void ThawBase::after_thaw_java_frame(const frame& f, bool bottom) {
2437 #ifdef ASSERT
2438 LogTarget(Trace, continuations) lt;
2439 if (lt.develop_is_enabled()) {
2440 LogStream ls(lt);
2441 ls.print_cr("thawed frame:");
2442 print_frame_layout(f, false, &ls); // f.print_on(&ls);
2443 }
2444 #endif
2445 }
2446
2447 inline void ThawBase::patch(frame& f, const frame& caller, bool bottom) {
2448 assert(!bottom || caller.fp() == _cont.entryFP(), "");
2449 if (bottom) {
2450 ContinuationHelper::Frame::patch_pc(caller, _cont.is_empty() ? caller.pc()
2451 : StubRoutines::cont_returnBarrier());
2452 } else {
2453 // caller might have been deoptimized during thaw but we've overwritten the return address when copying f from the heap.
2454 // If the caller is not deoptimized, pc is unchanged.
2455 ContinuationHelper::Frame::patch_pc(caller, caller.raw_pc());
2456 }
2457
2458 patch_pd(f, caller);
2459
2460 if (f.is_interpreted_frame()) {
2461 ContinuationHelper::InterpretedFrame::patch_sender_sp(f, caller);
2462 }
2463
2464 assert(!bottom || !_cont.is_empty() || Continuation::is_continuation_entry_frame(f, nullptr), "");
2465 assert(!bottom || (_cont.is_empty() != Continuation::is_cont_barrier_frame(f)), "");
2466 }
2467
2468 void ThawBase::clear_bitmap_bits(address start, address end) {
2469 assert(is_aligned(start, wordSize), "should be aligned: " PTR_FORMAT, p2i(start));
2470 assert(is_aligned(end, VMRegImpl::stack_slot_size), "should be aligned: " PTR_FORMAT, p2i(end));
2471
2472 // we need to clear the bits that correspond to arguments as they reside in the caller frame
2473 // or they will keep objects that are otherwise unreachable alive.
2474
2475 // Align `end` if UseCompressedOops is not set to avoid UB when calculating the bit index, since
2476 // `end` could be at an odd number of stack slots from `start`, i.e might not be oop aligned.
2477 // If that's the case the bit range corresponding to the last stack slot should not have bits set
2478 // anyways and we assert that before returning.
2479 address effective_end = UseCompressedOops ? end : align_down(end, wordSize);
2480 log_develop_trace(continuations)("clearing bitmap for " INTPTR_FORMAT " - " INTPTR_FORMAT, p2i(start), p2i(effective_end));
2481 stackChunkOop chunk = _cont.tail();
2482 chunk->bitmap().clear_range(chunk->bit_index_for(start), chunk->bit_index_for(effective_end));
2483 assert(effective_end == end || !chunk->bitmap().at(chunk->bit_index_for(effective_end)), "bit should not be set");
2484 }
2485
2486 intptr_t* ThawBase::handle_preempted_continuation(intptr_t* sp, Continuation::preempt_kind preempt_kind, bool fast_case) {
2487 assert(preempt_kind == Continuation::freeze_on_wait || preempt_kind == Continuation::freeze_on_monitorenter, "");
2488 frame top(sp);
2489 assert(top.pc() == *(address*)(sp - frame::sender_sp_ret_address_offset()), "");
2490
2491 #if INCLUDE_JVMTI
2492 // Finish the VTMS transition.
2493 assert(_thread->is_in_VTMS_transition(), "must be");
2494 bool is_vthread = Continuation::continuation_scope(_cont.continuation()) == java_lang_VirtualThread::vthread_scope();
2495 if (is_vthread) {
2496 if (JvmtiVTMSTransitionDisabler::VTMS_notify_jvmti_events()) {
2497 jvmti_mount_end(_thread, _cont, top);
2498 } else {
2499 _thread->set_is_in_VTMS_transition(false);
2500 java_lang_Thread::set_is_in_VTMS_transition(_thread->vthread(), false);
2501 }
2502 }
2503 #endif
2504
2505 if (fast_case) {
2506 // If we thawed in the slow path the runtime stub/native wrapper frame already
2507 // has the correct fp (see ThawBase::new_stack_frame). On the fast path though,
2508 // we copied the fp patched during freeze, which will now have to be fixed.
2509 assert(top.is_runtime_frame() || top.is_native_frame(), "");
2510 int fsize = top.cb()->frame_size();
2511 patch_pd(top, sp + fsize);
2512 }
2513
2514 if (preempt_kind == Continuation::freeze_on_wait) {
2515 // Check now if we need to throw IE exception.
2516 if (_thread->pending_interrupted_exception()) {
2517 throw_interrupted_exception(_thread, top);
2518 _thread->set_pending_interrupted_exception(false);
2519 }
2520 } else if (top.is_runtime_frame()) {
2521 // The continuation might now run on a different platform thread than the previous time so
2522 // we need to adjust the current thread saved in the stub frame before restoring registers.
2523 JavaThread** thread_addr = frame::saved_thread_address(top);
2524 if (thread_addr != nullptr) *thread_addr = _thread;
2525 }
2526 return sp;
2527 }
2528
2529 void ThawBase::throw_interrupted_exception(JavaThread* current, frame& top) {
2530 ContinuationWrapper::SafepointOp so(current, _cont);
2531 // Since we might safepoint set the anchor so that the stack can be walked.
2532 set_anchor(current, top.sp());
2533 JRT_BLOCK
2534 THROW(vmSymbols::java_lang_InterruptedException());
2535 JRT_BLOCK_END
2536 clear_anchor(current);
2537 }
2538
2539 NOINLINE void ThawBase::recurse_thaw_interpreted_frame(const frame& hf, frame& caller, int num_frames) {
2540 assert(hf.is_interpreted_frame(), "");
2541
2542 if (UNLIKELY(seen_by_gc())) {
2543 _cont.tail()->do_barriers<stackChunkOopDesc::BarrierType::Store>(_stream, SmallRegisterMap::instance());
2544 }
2545
2546 const bool is_bottom_frame = recurse_thaw_java_frame<ContinuationHelper::InterpretedFrame>(caller, num_frames);
2547
2548 DEBUG_ONLY(before_thaw_java_frame(hf, caller, is_bottom_frame, num_frames);)
2549
2550 _align_size += frame::align_wiggle; // possible added alignment for internal interpreted frame alignment om AArch64
2551
2552 frame f = new_stack_frame<ContinuationHelper::InterpretedFrame>(hf, caller, is_bottom_frame);
2553
2554 intptr_t* const stack_frame_top = f.sp() + frame::metadata_words_at_top;
2555 intptr_t* const stack_frame_bottom = ContinuationHelper::InterpretedFrame::frame_bottom(f);
2556 intptr_t* const heap_frame_top = hf.unextended_sp() + frame::metadata_words_at_top;
2557 intptr_t* const heap_frame_bottom = ContinuationHelper::InterpretedFrame::frame_bottom(hf);
2558
2559 assert(hf.is_heap_frame(), "should be");
2560 assert(!f.is_heap_frame(), "should not be");
2561
2562 const int fsize = pointer_delta_as_int(heap_frame_bottom, heap_frame_top);
2563 assert((stack_frame_bottom == stack_frame_top + fsize), "");
2564
2565 // Some architectures (like AArch64/PPC64/RISC-V) add padding between the locals and the fixed_frame to keep the fp 16-byte-aligned.
2566 // On those architectures we freeze the padding in order to keep the same fp-relative offsets in the fixed_frame.
2567 copy_from_chunk(heap_frame_top, stack_frame_top, fsize);
2568
2569 // Make sure the relativized locals is already set.
2570 assert(f.interpreter_frame_local_at(0) == stack_frame_bottom - 1, "invalid frame bottom");
2571
2572 derelativize_interpreted_frame_metadata(hf, f);
2573 patch(f, caller, is_bottom_frame);
2574
2575 assert(f.is_interpreted_frame_valid(_cont.thread()), "invalid thawed frame");
2576 assert(stack_frame_bottom <= ContinuationHelper::Frame::frame_top(caller), "");
2577
2578 CONT_JFR_ONLY(_jfr_info.record_interpreted_frame();)
2579
2580 maybe_set_fastpath(f.sp());
2581
2582 Method* m = hf.interpreter_frame_method();
2583 assert(!m->is_native() || !is_bottom_frame, "should be top frame of thaw_top case; missing caller frame");
2584 const int locals = m->max_locals();
2585
2586 if (!is_bottom_frame) {
2587 // can only fix caller once this frame is thawed (due to callee saved regs)
2588 _cont.tail()->fix_thawed_frame(caller, SmallRegisterMap::instance());
2589 } else if (_cont.tail()->has_bitmap() && locals > 0) {
2590 assert(hf.is_heap_frame(), "should be");
2591 address start = (address)(heap_frame_bottom - locals);
2592 address end = (address)heap_frame_bottom;
2593 clear_bitmap_bits(start, end);
2594 }
2595
2596 DEBUG_ONLY(after_thaw_java_frame(f, is_bottom_frame);)
2597 caller = f;
2598 }
2599
2600 void ThawBase::recurse_thaw_compiled_frame(const frame& hf, frame& caller, int num_frames, bool stub_caller) {
2601 assert(hf.is_compiled_frame(), "");
2602 assert(_preempted_case || !stub_caller, "stub caller not at preemption");
2603
2604 if (!stub_caller && UNLIKELY(seen_by_gc())) { // recurse_thaw_stub_frame already invoked our barriers with a full regmap
2605 _cont.tail()->do_barriers<stackChunkOopDesc::BarrierType::Store>(_stream, SmallRegisterMap::instance());
2606 }
2607
2608 const bool is_bottom_frame = recurse_thaw_java_frame<ContinuationHelper::CompiledFrame>(caller, num_frames);
2609
2610 DEBUG_ONLY(before_thaw_java_frame(hf, caller, is_bottom_frame, num_frames);)
2611
2612 assert(caller.sp() == caller.unextended_sp(), "");
2613
2614 if ((!is_bottom_frame && caller.is_interpreted_frame()) || (is_bottom_frame && Interpreter::contains(_cont.tail()->pc()))) {
2615 _align_size += frame::align_wiggle; // we add one whether or not we've aligned because we add it in recurse_freeze_compiled_frame
2616 }
2617
2618 // new_stack_frame must construct the resulting frame using hf.pc() rather than hf.raw_pc() because the frame is not
2619 // yet laid out in the stack, and so the original_pc is not stored in it.
2620 // As a result, f.is_deoptimized_frame() is always false and we must test hf to know if the frame is deoptimized.
2621 frame f = new_stack_frame<ContinuationHelper::CompiledFrame>(hf, caller, is_bottom_frame);
2622 intptr_t* const stack_frame_top = f.sp();
2623 intptr_t* const heap_frame_top = hf.unextended_sp();
2624
2625 const int added_argsize = (is_bottom_frame || caller.is_interpreted_frame()) ? hf.compiled_frame_stack_argsize() : 0;
2626 int fsize = ContinuationHelper::CompiledFrame::size(hf) + added_argsize;
2627 assert(fsize <= (int)(caller.unextended_sp() - f.unextended_sp()), "");
2628
2629 intptr_t* from = heap_frame_top - frame::metadata_words_at_bottom;
2630 intptr_t* to = stack_frame_top - frame::metadata_words_at_bottom;
2631 // copy metadata, except the metadata at the top of the (unextended) entry frame
2632 int sz = fsize + frame::metadata_words_at_bottom + (is_bottom_frame && added_argsize == 0 ? 0 : frame::metadata_words_at_top);
2633
2634 // If we're the bottom-most thawed frame, we're writing to within one word from entrySP
2635 // (we might have one padding word for alignment)
2636 assert(!is_bottom_frame || (_cont.entrySP() - 1 <= to + sz && to + sz <= _cont.entrySP()), "");
2637 assert(!is_bottom_frame || hf.compiled_frame_stack_argsize() != 0 || (to + sz && to + sz == _cont.entrySP()), "");
2638
2639 copy_from_chunk(from, to, sz); // copying good oops because we invoked barriers above
2640
2641 patch(f, caller, is_bottom_frame);
2642
2643 // f.is_deoptimized_frame() is always false and we must test hf.is_deoptimized_frame() (see comment above)
2644 assert(!f.is_deoptimized_frame(), "");
2645 if (hf.is_deoptimized_frame()) {
2646 maybe_set_fastpath(f.sp());
2647 } else if (_thread->is_interp_only_mode()
2648 || (stub_caller && f.cb()->as_nmethod()->is_marked_for_deoptimization())) {
2649 // The caller of the safepoint stub when the continuation is preempted is not at a call instruction, and so
2650 // cannot rely on nmethod patching for deopt.
2651 assert(_thread->is_interp_only_mode() || stub_caller, "expected a stub-caller");
2652
2653 log_develop_trace(continuations)("Deoptimizing thawed frame");
2654 DEBUG_ONLY(ContinuationHelper::Frame::patch_pc(f, nullptr));
2655
2656 f.deoptimize(nullptr); // the null thread simply avoids the assertion in deoptimize which we're not set up for
2657 assert(f.is_deoptimized_frame(), "");
2658 assert(ContinuationHelper::Frame::is_deopt_return(f.raw_pc(), f), "");
2659 maybe_set_fastpath(f.sp());
2660 }
2661
2662 if (!is_bottom_frame) {
2663 // can only fix caller once this frame is thawed (due to callee saved regs); this happens on the stack
2664 _cont.tail()->fix_thawed_frame(caller, SmallRegisterMap::instance());
2665 } else if (_cont.tail()->has_bitmap() && added_argsize > 0) {
2666 address start = (address)(heap_frame_top + ContinuationHelper::CompiledFrame::size(hf) + frame::metadata_words_at_top);
2667 int stack_args_slots = f.cb()->as_nmethod()->num_stack_arg_slots(false /* rounded */);
2668 int argsize_in_bytes = stack_args_slots * VMRegImpl::stack_slot_size;
2669 clear_bitmap_bits(start, start + argsize_in_bytes);
2670 }
2671
2672 DEBUG_ONLY(after_thaw_java_frame(f, is_bottom_frame);)
2673 caller = f;
2674 }
2675
2676 void ThawBase::recurse_thaw_stub_frame(const frame& hf, frame& caller, int num_frames) {
2677 DEBUG_ONLY(_frames++;)
2678
2679 if (UNLIKELY(seen_by_gc())) {
2680 // Process the stub's caller here since we might need the full map.
2681 RegisterMap map(nullptr,
2682 RegisterMap::UpdateMap::include,
2683 RegisterMap::ProcessFrames::skip,
2684 RegisterMap::WalkContinuation::skip);
2685 map.set_include_argument_oops(false);
2686 _stream.next(&map);
2687 assert(!_stream.is_done(), "");
2688 _cont.tail()->do_barriers<stackChunkOopDesc::BarrierType::Store>(_stream, &map);
2689 } else {
2690 _stream.next(SmallRegisterMap::instance());
2691 assert(!_stream.is_done(), "");
2692 }
2693
2694 recurse_thaw_compiled_frame(_stream.to_frame(), caller, num_frames, true);
2695
2696 assert(caller.is_compiled_frame(), "");
2697 assert(caller.sp() == caller.unextended_sp(), "");
2698
2699 DEBUG_ONLY(before_thaw_java_frame(hf, caller, false /*is_bottom_frame*/, num_frames);)
2700
2701 frame f = new_stack_frame<ContinuationHelper::StubFrame>(hf, caller, false);
2702 intptr_t* stack_frame_top = f.sp();
2703 intptr_t* heap_frame_top = hf.sp();
2704 int fsize = ContinuationHelper::StubFrame::size(hf);
2705
2706 copy_from_chunk(heap_frame_top - frame::metadata_words, stack_frame_top - frame::metadata_words,
2707 fsize + frame::metadata_words);
2708
2709 patch(f, caller, false /*is_bottom_frame*/);
2710
2711 // can only fix caller once this frame is thawed (due to callee saved regs)
2712 RegisterMap map(nullptr,
2713 RegisterMap::UpdateMap::include,
2714 RegisterMap::ProcessFrames::skip,
2715 RegisterMap::WalkContinuation::skip);
2716 map.set_include_argument_oops(false);
2717 f.oop_map()->update_register_map(&f, &map);
2718 ContinuationHelper::update_register_map_with_callee(caller, &map);
2719 _cont.tail()->fix_thawed_frame(caller, &map);
2720
2721 DEBUG_ONLY(after_thaw_java_frame(f, false /*is_bottom_frame*/);)
2722 caller = f;
2723 }
2724
2725 void ThawBase::recurse_thaw_native_frame(const frame& hf, frame& caller, int num_frames) {
2726 assert(hf.is_native_frame(), "");
2727 assert(_preempted_case && hf.cb()->as_nmethod()->method()->is_object_wait0(), "");
2728
2729 if (UNLIKELY(seen_by_gc())) { // recurse_thaw_stub_frame already invoked our barriers with a full regmap
2730 _cont.tail()->do_barriers<stackChunkOopDesc::BarrierType::Store>(_stream, SmallRegisterMap::instance());
2731 }
2732
2733 const bool is_bottom_frame = recurse_thaw_java_frame<ContinuationHelper::NativeFrame>(caller, num_frames);
2734 assert(!is_bottom_frame, "");
2735
2736 DEBUG_ONLY(before_thaw_java_frame(hf, caller, is_bottom_frame, num_frames);)
2737
2738 assert(caller.sp() == caller.unextended_sp(), "");
2739
2740 if (caller.is_interpreted_frame()) {
2741 _align_size += frame::align_wiggle; // we add one whether or not we've aligned because we add it in recurse_freeze_native_frame
2742 }
2743
2744 // new_stack_frame must construct the resulting frame using hf.pc() rather than hf.raw_pc() because the frame is not
2745 // yet laid out in the stack, and so the original_pc is not stored in it.
2746 // As a result, f.is_deoptimized_frame() is always false and we must test hf to know if the frame is deoptimized.
2747 frame f = new_stack_frame<ContinuationHelper::NativeFrame>(hf, caller, false /* bottom */);
2748 intptr_t* const stack_frame_top = f.sp();
2749 intptr_t* const heap_frame_top = hf.unextended_sp();
2750
2751 int fsize = ContinuationHelper::NativeFrame::size(hf);
2752 assert(fsize <= (int)(caller.unextended_sp() - f.unextended_sp()), "");
2753
2754 intptr_t* from = heap_frame_top - frame::metadata_words_at_bottom;
2755 intptr_t* to = stack_frame_top - frame::metadata_words_at_bottom;
2756 int sz = fsize + frame::metadata_words_at_bottom;
2757
2758 copy_from_chunk(from, to, sz); // copying good oops because we invoked barriers above
2759
2760 patch(f, caller, false /* bottom */);
2761
2762 // f.is_deoptimized_frame() is always false and we must test hf.is_deoptimized_frame() (see comment above)
2763 assert(!f.is_deoptimized_frame(), "");
2764 assert(!hf.is_deoptimized_frame(), "");
2765 assert(!f.cb()->as_nmethod()->is_marked_for_deoptimization(), "");
2766
2767 // can only fix caller once this frame is thawed (due to callee saved regs); this happens on the stack
2768 _cont.tail()->fix_thawed_frame(caller, SmallRegisterMap::instance());
2769
2770 DEBUG_ONLY(after_thaw_java_frame(f, false /* bottom */);)
2771 caller = f;
2772 }
2773
2774 void ThawBase::finish_thaw(frame& f) {
2775 stackChunkOop chunk = _cont.tail();
2776
2777 if (chunk->is_empty()) {
2778 // Only remove chunk from list if it can't be reused for another freeze
2779 if (seen_by_gc()) {
2780 _cont.set_tail(chunk->parent());
2781 } else {
2782 chunk->set_has_mixed_frames(false);
2783 }
2784 chunk->set_max_thawing_size(0);
2785 } else {
2786 chunk->set_max_thawing_size(chunk->max_thawing_size() - _align_size);
2787 }
2788 assert(chunk->is_empty() == (chunk->max_thawing_size() == 0), "");
2789
2790 if (!is_aligned(f.sp(), frame::frame_alignment)) {
2791 assert(f.is_interpreted_frame(), "");
2792 f.set_sp(align_down(f.sp(), frame::frame_alignment));
2793 }
2794 push_return_frame(f);
2795 chunk->fix_thawed_frame(f, SmallRegisterMap::instance()); // can only fix caller after push_return_frame (due to callee saved regs)
2796
2797 assert(_cont.is_empty() == _cont.last_frame().is_empty(), "");
2798
2799 log_develop_trace(continuations)("thawed %d frames", _frames);
2800
2801 LogTarget(Trace, continuations) lt;
2802 if (lt.develop_is_enabled()) {
2803 LogStream ls(lt);
2804 ls.print_cr("top hframe after (thaw):");
2805 _cont.last_frame().print_value_on(&ls);
2806 }
2807 }
2808
2809 void ThawBase::push_return_frame(frame& f) { // see generate_cont_thaw
2810 assert(!f.is_compiled_frame() || f.is_deoptimized_frame() == f.cb()->as_nmethod()->is_deopt_pc(f.raw_pc()), "");
2811 assert(!f.is_compiled_frame() || f.is_deoptimized_frame() == (f.pc() != f.raw_pc()), "");
2812
2813 LogTarget(Trace, continuations) lt;
2814 if (lt.develop_is_enabled()) {
2815 LogStream ls(lt);
2816 ls.print_cr("push_return_frame");
2817 f.print_value_on(&ls);
2818 }
2819
2820 assert(f.sp() - frame::metadata_words_at_bottom >= _top_stack_address, "overwrote past thawing space"
2821 " to: " INTPTR_FORMAT " top_address: " INTPTR_FORMAT, p2i(f.sp() - frame::metadata_words), p2i(_top_stack_address));
2822 ContinuationHelper::Frame::patch_pc(f, f.raw_pc()); // in case we want to deopt the frame in a full transition, this is checked.
2823 ContinuationHelper::push_pd(f);
2824
2825 assert(ContinuationHelper::Frame::assert_frame_laid_out(f), "");
2826 }
2827
2828 // returns new top sp
2829 // called after preparations (stack overflow check and making room)
2830 template<typename ConfigT>
2831 static inline intptr_t* thaw_internal(JavaThread* thread, const Continuation::thaw_kind kind) {
2832 assert(thread == JavaThread::current(), "Must be current thread");
2833
2834 CONT_JFR_ONLY(EventContinuationThaw event;)
2835
2836 log_develop_trace(continuations)("~~~~ thaw kind: %d sp: " INTPTR_FORMAT, kind, p2i(thread->last_continuation()->entry_sp()));
2837
2838 ContinuationEntry* entry = thread->last_continuation();
2839 assert(entry != nullptr, "");
2840 oop oopCont = entry->cont_oop(thread);
2841
2842 assert(!jdk_internal_vm_Continuation::done(oopCont), "");
2843 assert(oopCont == get_continuation(thread), "");
2844 verify_continuation(oopCont);
2845
2846 assert(entry->is_virtual_thread() == (entry->scope(thread) == java_lang_VirtualThread::vthread_scope()), "");
2847
2848 ContinuationWrapper cont(thread, oopCont);
2849 log_develop_debug(continuations)("THAW #" INTPTR_FORMAT " " INTPTR_FORMAT, cont.hash(), p2i((oopDesc*)oopCont));
2850
2851 #ifdef ASSERT
2852 set_anchor_to_entry(thread, cont.entry());
2853 log_frames(thread);
2854 clear_anchor(thread);
2855 #endif
2856
2857 DEBUG_ONLY(bool preempted = cont.tail()->preempted();)
2858 Thaw<ConfigT> thw(thread, cont);
2859 intptr_t* const sp = thw.thaw(kind);
2860 assert(is_aligned(sp, frame::frame_alignment), "");
2861 DEBUG_ONLY(log_frames_after_thaw(thread, cont, sp, preempted);)
2862
2863 CONT_JFR_ONLY(thw.jfr_info().post_jfr_event(&event, cont.continuation(), thread);)
2864
2865 verify_continuation(cont.continuation());
2866 log_develop_debug(continuations)("=== End of thaw #" INTPTR_FORMAT, cont.hash());
2867
2868 return sp;
2869 }
2870
2871 #ifdef ASSERT
2872 static void do_deopt_after_thaw(JavaThread* thread) {
2873 int i = 0;
2874 StackFrameStream fst(thread, true, false);
2875 fst.register_map()->set_include_argument_oops(false);
2876 ContinuationHelper::update_register_map_with_callee(*fst.current(), fst.register_map());
2877 for (; !fst.is_done(); fst.next()) {
2878 if (fst.current()->cb()->is_nmethod()) {
2879 nmethod* nm = fst.current()->cb()->as_nmethod();
2880 if (!nm->method()->is_continuation_native_intrinsic()) {
2881 nm->make_deoptimized();
2882 }
2883 }
2884 }
2885 }
2886
2887 class ThawVerifyOopsClosure: public OopClosure {
2888 intptr_t* _p;
2889 outputStream* _st;
2890 bool is_good_oop(oop o) {
2891 return dbg_is_safe(o, -1) && dbg_is_safe(o->klass(), -1) && oopDesc::is_oop(o) && o->klass()->is_klass();
2892 }
2893 public:
2894 ThawVerifyOopsClosure(outputStream* st) : _p(nullptr), _st(st) {}
2895 intptr_t* p() { return _p; }
2896 void reset() { _p = nullptr; }
2897
2898 virtual void do_oop(oop* p) {
2899 oop o = *p;
2900 if (o == nullptr || is_good_oop(o)) {
2901 return;
2902 }
2903 _p = (intptr_t*)p;
2904 _st->print_cr("*** non-oop " PTR_FORMAT " found at " PTR_FORMAT, p2i(*p), p2i(p));
2905 }
2906 virtual void do_oop(narrowOop* p) {
2907 oop o = RawAccess<>::oop_load(p);
2908 if (o == nullptr || is_good_oop(o)) {
2909 return;
2910 }
2911 _p = (intptr_t*)p;
2912 _st->print_cr("*** (narrow) non-oop %x found at " PTR_FORMAT, (int)(*p), p2i(p));
2913 }
2914 };
2915
2916 static bool do_verify_after_thaw(JavaThread* thread, stackChunkOop chunk, outputStream* st) {
2917 assert(thread->has_last_Java_frame(), "");
2918
2919 ResourceMark rm;
2920 ThawVerifyOopsClosure cl(st);
2921 NMethodToOopClosure cf(&cl, false);
2922
2923 StackFrameStream fst(thread, true, false);
2924 fst.register_map()->set_include_argument_oops(false);
2925 ContinuationHelper::update_register_map_with_callee(*fst.current(), fst.register_map());
2926 for (; !fst.is_done() && !Continuation::is_continuation_enterSpecial(*fst.current()); fst.next()) {
2927 if (fst.current()->cb()->is_nmethod() && fst.current()->cb()->as_nmethod()->is_marked_for_deoptimization()) {
2928 st->print_cr(">>> do_verify_after_thaw deopt");
2929 fst.current()->deoptimize(nullptr);
2930 fst.current()->print_on(st);
2931 }
2932
2933 fst.current()->oops_do(&cl, &cf, fst.register_map());
2934 if (cl.p() != nullptr) {
2935 frame fr = *fst.current();
2936 st->print_cr("Failed for frame barriers: %d",chunk->requires_barriers());
2937 fr.print_on(st);
2938 if (!fr.is_interpreted_frame()) {
2939 st->print_cr("size: %d argsize: %d",
2940 ContinuationHelper::NonInterpretedUnknownFrame::size(fr),
2941 ContinuationHelper::NonInterpretedUnknownFrame::stack_argsize(fr));
2942 }
2943 VMReg reg = fst.register_map()->find_register_spilled_here(cl.p(), fst.current()->sp());
2944 if (reg != nullptr) {
2945 st->print_cr("Reg %s %d", reg->name(), reg->is_stack() ? (int)reg->reg2stack() : -99);
2946 }
2947 cl.reset();
2948 DEBUG_ONLY(thread->print_frame_layout();)
2949 if (chunk != nullptr) {
2950 chunk->print_on(true, st);
2951 }
2952 return false;
2953 }
2954 }
2955 return true;
2956 }
2957
2958 static void log_frames(JavaThread* thread) {
2959 const static int show_entry_callers = 3;
2960 LogTarget(Trace, continuations) lt;
2961 if (!lt.develop_is_enabled()) {
2962 return;
2963 }
2964 LogStream ls(lt);
2965
2966 ls.print_cr("------- frames --------- for thread " INTPTR_FORMAT, p2i(thread));
2967 if (!thread->has_last_Java_frame()) {
2968 ls.print_cr("NO ANCHOR!");
2969 }
2970
2971 RegisterMap map(thread,
2972 RegisterMap::UpdateMap::include,
2973 RegisterMap::ProcessFrames::include,
2974 RegisterMap::WalkContinuation::skip);
2975 map.set_include_argument_oops(false);
2976
2977 if (false) {
2978 for (frame f = thread->last_frame(); !f.is_entry_frame(); f = f.sender(&map)) {
2979 f.print_on(&ls);
2980 }
2981 } else {
2982 map.set_skip_missing(true);
2983 ResetNoHandleMark rnhm;
2984 ResourceMark rm;
2985 HandleMark hm(Thread::current());
2986 FrameValues values;
2987
2988 int i = 0;
2989 int post_entry = -1;
2990 for (frame f = thread->last_frame(); !f.is_first_frame(); f = f.sender(&map), i++) {
2991 f.describe(values, i, &map, i == 0);
2992 if (post_entry >= 0 || Continuation::is_continuation_enterSpecial(f))
2993 post_entry++;
2994 if (post_entry >= show_entry_callers)
2995 break;
2996 }
2997 values.print_on(thread, &ls);
2998 }
2999
3000 ls.print_cr("======= end frames =========");
3001 }
3002
3003 static void log_frames_after_thaw(JavaThread* thread, ContinuationWrapper& cont, intptr_t* sp, bool preempted) {
3004 intptr_t* sp0 = sp;
3005 address pc0 = *(address*)(sp - frame::sender_sp_ret_address_offset());
3006
3007 if (preempted && sp0 == cont.entrySP()) {
3008 // Still preempted (monitor not acquired) so no frames were thawed.
3009 assert(cont.tail()->preempted(), "");
3010 set_anchor(thread, cont.entrySP(), cont.entryPC());
3011 } else {
3012 set_anchor(thread, sp0);
3013 }
3014
3015 log_frames(thread);
3016 if (LoomVerifyAfterThaw) {
3017 assert(do_verify_after_thaw(thread, cont.tail(), tty), "");
3018 }
3019 assert(ContinuationEntry::assert_entry_frame_laid_out(thread), "");
3020 clear_anchor(thread);
3021
3022 LogTarget(Trace, continuations) lt;
3023 if (lt.develop_is_enabled()) {
3024 LogStream ls(lt);
3025 ls.print_cr("Jumping to frame (thaw):");
3026 frame(sp).print_value_on(&ls);
3027 }
3028 }
3029 #endif // ASSERT
3030
3031 #include CPU_HEADER_INLINE(continuationFreezeThaw)
3032
3033 #ifdef ASSERT
3034 static void print_frame_layout(const frame& f, bool callee_complete, outputStream* st) {
3035 ResourceMark rm;
3036 FrameValues values;
3037 assert(f.get_cb() != nullptr, "");
3038 RegisterMap map(f.is_heap_frame() ?
3039 nullptr :
3040 JavaThread::current(),
3041 RegisterMap::UpdateMap::include,
3042 RegisterMap::ProcessFrames::skip,
3043 RegisterMap::WalkContinuation::skip);
3044 map.set_include_argument_oops(false);
3045 map.set_skip_missing(true);
3046 if (callee_complete) {
3047 frame::update_map_with_saved_link(&map, ContinuationHelper::Frame::callee_link_address(f));
3048 }
3049 const_cast<frame&>(f).describe(values, 0, &map, true);
3050 values.print_on(static_cast<JavaThread*>(nullptr), st);
3051 }
3052 #endif
3053
3054 static address thaw_entry = nullptr;
3055 static address freeze_entry = nullptr;
3056 static address freeze_preempt_entry = nullptr;
3057
3058 address Continuation::thaw_entry() {
3059 return ::thaw_entry;
3060 }
3061
3062 address Continuation::freeze_entry() {
3063 return ::freeze_entry;
3064 }
3065
3066 address Continuation::freeze_preempt_entry() {
3067 return ::freeze_preempt_entry;
3068 }
3069
3070 class ConfigResolve {
3071 public:
3072 static void resolve() { resolve_compressed(); }
3073
3074 static void resolve_compressed() {
3075 UseCompressedOops ? resolve_gc<true>()
3076 : resolve_gc<false>();
3077 }
3078
3079 private:
3080 template <bool use_compressed>
3081 static void resolve_gc() {
3082 BarrierSet* bs = BarrierSet::barrier_set();
3083 assert(bs != nullptr, "freeze/thaw invoked before BarrierSet is set");
3084 switch (bs->kind()) {
3085 #define BARRIER_SET_RESOLVE_BARRIER_CLOSURE(bs_name) \
3086 case BarrierSet::bs_name: { \
3087 resolve<use_compressed, typename BarrierSet::GetType<BarrierSet::bs_name>::type>(); \
3088 } \
3089 break;
3090 FOR_EACH_CONCRETE_BARRIER_SET_DO(BARRIER_SET_RESOLVE_BARRIER_CLOSURE)
3091 #undef BARRIER_SET_RESOLVE_BARRIER_CLOSURE
3092
3093 default:
3094 fatal("BarrierSet resolving not implemented");
3095 };
3096 }
3097
3098 template <bool use_compressed, typename BarrierSetT>
3099 static void resolve() {
3100 typedef Config<use_compressed ? oop_kind::NARROW : oop_kind::WIDE, BarrierSetT> SelectedConfigT;
3101
3102 freeze_entry = (address)freeze<SelectedConfigT>;
3103 freeze_preempt_entry = (address)SelectedConfigT::freeze_preempt;
3104
3105 // If we wanted, we could templatize by kind and have three different thaw entries
3106 thaw_entry = (address)thaw<SelectedConfigT>;
3107 }
3108 };
3109
3110 void Continuation::init() {
3111 ConfigResolve::resolve();
3112 }