1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "classfile/systemDictionary.hpp"
28 #include "code/codeCache.hpp"
29 #include "code/icBuffer.hpp"
30 #include "code/nmethod.hpp"
31 #include "code/vtableStubs.hpp"
32 #include "compiler/compileBroker.hpp"
33 #include "compiler/disassembler.hpp"
34 #include "gc/shared/collectedHeap.hpp"
35 #include "interpreter/bytecodeHistogram.hpp"
36 #include "interpreter/interpreter.hpp"
37 #include "memory/resourceArea.hpp"
38 #include "memory/universe.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "prims/privilegedStack.hpp"
41 #include "runtime/arguments.hpp"
42 #include "runtime/atomic.hpp"
43 #include "runtime/frame.hpp"
44 #include "runtime/java.hpp"
45 #include "runtime/os.hpp"
46 #include "runtime/sharedRuntime.hpp"
47 #include "runtime/stubCodeGenerator.hpp"
48 #include "runtime/stubRoutines.hpp"
49 #include "runtime/thread.inline.hpp"
50 #include "runtime/vframe.hpp"
51 #include "runtime/vm_version.hpp"
52 #include "services/heapDumper.hpp"
53 #include "utilities/defaultStream.hpp"
54 #include "utilities/events.hpp"
55 #include "utilities/formatBuffer.hpp"
56 #include "utilities/globalDefinitions.hpp"
57 #include "utilities/macros.hpp"
58 #include "utilities/vmError.hpp"
59
60 #include <stdio.h>
61
62 // Support for showing register content on asserts/guarantees.
63 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
64 static intptr_t g_dummy;
65 void* volatile g_assert_poison = &g_dummy;
66 static intx g_asserting_thread = 0;
67 static void* g_assertion_context = NULL;
68 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
69
70 #ifndef ASSERT
71 # ifdef _DEBUG
72 // NOTE: don't turn the lines below into a comment -- if you're getting
73 // a compile error here, change the settings to define ASSERT
74 ASSERT should be defined when _DEBUG is defined. It is not intended to be used for debugging
75 functions that do not slow down the system too much and thus can be left in optimized code.
76 On the other hand, the code should not be included in a production version.
77 # endif // _DEBUG
78 #endif // ASSERT
79
80
81 #ifdef _DEBUG
82 # ifndef ASSERT
83 configuration error: ASSERT must be defined in debug version
84 # endif // ASSERT
85 #endif // _DEBUG
86
87
88 #ifdef PRODUCT
89 # if -defined _DEBUG || -defined ASSERT
90 configuration error: ASSERT et al. must not be defined in PRODUCT version
91 # endif
92 #endif // PRODUCT
93
94 ATTRIBUTE_PRINTF(1, 2)
95 void warning(const char* format, ...) {
96 if (PrintWarnings) {
97 FILE* const err = defaultStream::error_stream();
98 jio_fprintf(err, "%s warning: ", VM_Version::vm_name());
99 va_list ap;
100 va_start(ap, format);
101 vfprintf(err, format, ap);
102 va_end(ap);
103 fputc('\n', err);
104 }
105 if (BreakAtWarning) BREAKPOINT;
106 }
107
108 #ifndef PRODUCT
109
110 #define is_token_break(ch) (isspace(ch) || (ch) == ',')
111
112 static const char* last_file_name = NULL;
113 static int last_line_no = -1;
114
115 // assert/guarantee/... may happen very early during VM initialization.
116 // Don't rely on anything that is initialized by Threads::create_vm(). For
117 // example, don't use tty.
118 bool error_is_suppressed(const char* file_name, int line_no) {
119 // The following 1-element cache requires that passed-in
120 // file names are always only constant literals.
121 if (file_name == last_file_name && line_no == last_line_no) return true;
122
123 int file_name_len = (int)strlen(file_name);
124 char separator = os::file_separator()[0];
125 const char* base_name = strrchr(file_name, separator);
126 if (base_name == NULL)
127 base_name = file_name;
128
129 // scan the SuppressErrorAt option
130 const char* cp = SuppressErrorAt;
131 for (;;) {
132 const char* sfile;
133 int sfile_len;
134 int sline;
135 bool noisy;
136 while ((*cp) != '\0' && is_token_break(*cp)) cp++;
137 if ((*cp) == '\0') break;
138 sfile = cp;
139 while ((*cp) != '\0' && !is_token_break(*cp) && (*cp) != ':') cp++;
140 sfile_len = cp - sfile;
141 if ((*cp) == ':') cp++;
142 sline = 0;
143 while ((*cp) != '\0' && isdigit(*cp)) {
144 sline *= 10;
145 sline += (*cp) - '0';
146 cp++;
147 }
148 // "file:line!" means the assert suppression is not silent
149 noisy = ((*cp) == '!');
150 while ((*cp) != '\0' && !is_token_break(*cp)) cp++;
151 // match the line
152 if (sline != 0) {
153 if (sline != line_no) continue;
154 }
155 // match the file
156 if (sfile_len > 0) {
157 const char* look = file_name;
158 const char* look_max = file_name + file_name_len - sfile_len;
159 const char* foundp;
160 bool match = false;
161 while (!match
162 && (foundp = strchr(look, sfile[0])) != NULL
163 && foundp <= look_max) {
164 match = true;
165 for (int i = 1; i < sfile_len; i++) {
166 if (sfile[i] != foundp[i]) {
167 match = false;
168 break;
169 }
170 }
171 look = foundp + 1;
172 }
173 if (!match) continue;
174 }
175 // got a match!
176 if (noisy) {
177 fdStream out(defaultStream::output_fd());
178 out.print_raw("[error suppressed at ");
179 out.print_raw(base_name);
180 char buf[16];
181 jio_snprintf(buf, sizeof(buf), ":%d]", line_no);
182 out.print_raw_cr(buf);
183 } else {
184 // update 1-element cache for fast silent matches
185 last_file_name = file_name;
186 last_line_no = line_no;
187 }
188 return true;
189 }
190
191 if (!VMError::is_error_reported() && !SuppressFatalErrorMessage) {
192 // print a friendly hint:
193 fdStream out(defaultStream::output_fd());
194 out.print_raw_cr("# To suppress the following error report, specify this argument");
195 out.print_raw ("# after -XX: or in .hotspotrc: SuppressErrorAt=");
196 out.print_raw (base_name);
197 char buf[16];
198 jio_snprintf(buf, sizeof(buf), ":%d", line_no);
199 out.print_raw_cr(buf);
200 }
201 return false;
202 }
203
204 #undef is_token_break
205
206 #else
207
208 // Place-holder for non-existent suppression check:
209 #define error_is_suppressed(file_name, line_no) (false)
210
211 #endif // !PRODUCT
212
213 void report_vm_error(const char* file, int line, const char* error_msg)
214 {
215 report_vm_error(file, line, error_msg, "%s", "");
216 }
217
218 void report_vm_error(const char* file, int line, const char* error_msg, const char* detail_fmt, ...)
219 {
220 if (Debugging || error_is_suppressed(file, line)) return;
221 va_list detail_args;
222 va_start(detail_args, detail_fmt);
223 void* context = NULL;
224 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
225 if (g_assertion_context != NULL && os::current_thread_id() == g_asserting_thread) {
226 context = g_assertion_context;
227 }
228 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
229 VMError::report_and_die(Thread::current_or_null(), context, file, line, error_msg, detail_fmt, detail_args);
230 va_end(detail_args);
231 }
232
233 void report_vm_status_error(const char* file, int line, const char* error_msg,
234 int status, const char* detail) {
235 report_vm_error(file, line, error_msg, "error %s(%d), %s", os::errno_name(status), status, detail);
236 }
237
238 void report_fatal(const char* file, int line, const char* detail_fmt, ...)
239 {
240 if (Debugging || error_is_suppressed(file, line)) return;
241 va_list detail_args;
242 va_start(detail_args, detail_fmt);
243 void* context = NULL;
244 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
245 if (g_assertion_context != NULL && os::current_thread_id() == g_asserting_thread) {
246 context = g_assertion_context;
247 }
248 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
249 VMError::report_and_die(Thread::current_or_null(), context, file, line, "fatal error", detail_fmt, detail_args);
250 va_end(detail_args);
251 }
252
253 void report_vm_out_of_memory(const char* file, int line, size_t size,
254 VMErrorType vm_err_type, const char* detail_fmt, ...) {
255 if (Debugging) return;
256 va_list detail_args;
257 va_start(detail_args, detail_fmt);
258 VMError::report_and_die(Thread::current_or_null(), file, line, size, vm_err_type, detail_fmt, detail_args);
259 va_end(detail_args);
260
261 // The UseOSErrorReporting option in report_and_die() may allow a return
262 // to here. If so then we'll have to figure out how to handle it.
263 guarantee(false, "report_and_die() should not return here");
264 }
265
266 void report_should_not_call(const char* file, int line) {
267 report_vm_error(file, line, "ShouldNotCall()");
268 }
269
270 void report_should_not_reach_here(const char* file, int line) {
271 report_vm_error(file, line, "ShouldNotReachHere()");
272 }
273
274 void report_unimplemented(const char* file, int line) {
275 report_vm_error(file, line, "Unimplemented()");
276 }
277
278 #ifdef ASSERT
279 bool is_executing_unit_tests() {
280 return ExecutingUnitTests;
281 }
282
283 void report_assert_msg(const char* msg, ...) {
284 va_list ap;
285 va_start(ap, msg);
286
287 fprintf(stderr, "assert failed: %s\n", err_msg(FormatBufferDummy(), msg, ap).buffer());
288
289 va_end(ap);
290 }
291 #endif // ASSERT
292
293 void report_untested(const char* file, int line, const char* message) {
294 #ifndef PRODUCT
295 warning("Untested: %s in %s: %d\n", message, file, line);
296 #endif // !PRODUCT
297 }
298
299 void report_java_out_of_memory(const char* message) {
300 static int out_of_memory_reported = 0;
301
302 // A number of threads may attempt to report OutOfMemoryError at around the
303 // same time. To avoid dumping the heap or executing the data collection
304 // commands multiple times we just do it once when the first threads reports
305 // the error.
306 if (Atomic::cmpxchg(1, &out_of_memory_reported, 0) == 0) {
307 // create heap dump before OnOutOfMemoryError commands are executed
308 if (HeapDumpOnOutOfMemoryError) {
309 tty->print_cr("java.lang.OutOfMemoryError: %s", message);
310 HeapDumper::dump_heap_from_oome();
311 }
312
313 if (OnOutOfMemoryError && OnOutOfMemoryError[0]) {
314 VMError::report_java_out_of_memory(message);
315 }
316
317 if (CrashOnOutOfMemoryError) {
318 tty->print_cr("Aborting due to java.lang.OutOfMemoryError: %s", message);
319 fatal("OutOfMemory encountered: %s", message);
320 }
321
322 if (ExitOnOutOfMemoryError) {
323 tty->print_cr("Terminating due to java.lang.OutOfMemoryError: %s", message);
324 os::exit(3);
325 }
326 }
327 }
328
329 // ------ helper functions for debugging go here ------------
330
331 // All debug entries should be wrapped with a stack allocated
332 // Command object. It makes sure a resource mark is set and
333 // flushes the logfile to prevent file sharing problems.
334
335 class Command : public StackObj {
336 private:
337 ResourceMark rm;
338 ResetNoHandleMark rnhm;
339 HandleMark hm;
340 bool debug_save;
341 public:
342 static int level;
343 Command(const char* str) {
344 debug_save = Debugging;
345 Debugging = true;
346 if (level++ > 0) return;
347 tty->cr();
348 tty->print_cr("\"Executing %s\"", str);
349 }
350
351 ~Command() {
352 tty->flush();
353 Debugging = debug_save;
354 level--;
355 }
356 };
357
358 int Command::level = 0;
359
360 #ifndef PRODUCT
361
362 extern "C" void blob(CodeBlob* cb) {
363 Command c("blob");
364 cb->print();
365 }
366
367
368 extern "C" void dump_vtable(address p) {
369 Command c("dump_vtable");
370 Klass* k = (Klass*)p;
371 k->vtable().print();
372 }
373
374
375 extern "C" void nm(intptr_t p) {
376 // Actually we look through all CodeBlobs (the nm name has been kept for backwards compatability)
377 Command c("nm");
378 CodeBlob* cb = CodeCache::find_blob((address)p);
379 if (cb == NULL) {
380 tty->print_cr("NULL");
381 } else {
382 cb->print();
383 }
384 }
385
386
387 extern "C" void disnm(intptr_t p) {
388 Command c("disnm");
389 CodeBlob* cb = CodeCache::find_blob((address) p);
390 if (cb != NULL) {
391 nmethod* nm = cb->as_nmethod_or_null();
392 if (nm != NULL) {
393 nm->print();
394 } else {
395 cb->print();
396 }
397 Disassembler::decode(cb);
398 }
399 }
400
401
402 extern "C" void printnm(intptr_t p) {
403 char buffer[256];
404 sprintf(buffer, "printnm: " INTPTR_FORMAT, p);
405 Command c(buffer);
406 CodeBlob* cb = CodeCache::find_blob((address) p);
407 if (cb->is_nmethod()) {
408 nmethod* nm = (nmethod*)cb;
409 nm->print_nmethod(true);
410 }
411 }
412
413
414 extern "C" void universe() {
415 Command c("universe");
416 Universe::print_on(tty);
417 }
418
419
420 extern "C" void verify() {
421 // try to run a verify on the entire system
422 // note: this may not be safe if we're not at a safepoint; for debugging,
423 // this manipulates the safepoint settings to avoid assertion failures
424 Command c("universe verify");
425 bool safe = SafepointSynchronize::is_at_safepoint();
426 if (!safe) {
427 tty->print_cr("warning: not at safepoint -- verify may fail");
428 SafepointSynchronize::set_is_at_safepoint();
429 }
430 // Ensure Eden top is correct before verification
431 Universe::heap()->prepare_for_verify();
432 Universe::verify();
433 if (!safe) SafepointSynchronize::set_is_not_at_safepoint();
434 }
435
436
437 extern "C" void pp(void* p) {
438 Command c("pp");
439 FlagSetting fl(PrintVMMessages, true);
440 FlagSetting f2(DisplayVMOutput, true);
441 if (Universe::heap()->is_in(p)) {
442 oop obj = oop(p);
443 obj->print();
444 } else {
445 tty->print(PTR_FORMAT, p2i(p));
446 }
447 }
448
449
450 // pv: print vm-printable object
451 extern "C" void pa(intptr_t p) { ((AllocatedObj*) p)->print(); }
452 extern "C" void findpc(intptr_t x);
453
454 #endif // !PRODUCT
455
456 extern "C" void ps() { // print stack
457 if (Thread::current_or_null() == NULL) return;
458 Command c("ps");
459
460
461 // Prints the stack of the current Java thread
462 JavaThread* p = JavaThread::active();
463 tty->print(" for thread: ");
464 p->print();
465 tty->cr();
466
467 if (p->has_last_Java_frame()) {
468 // If the last_Java_fp is set we are in C land and
469 // can call the standard stack_trace function.
470 #ifdef PRODUCT
471 p->print_stack();
472 } else {
473 tty->print_cr("Cannot find the last Java frame, printing stack disabled.");
474 #else // !PRODUCT
475 p->trace_stack();
476 } else {
477 frame f = os::current_frame();
478 RegisterMap reg_map(p);
479 f = f.sender(®_map);
480 tty->print("(guessing starting frame id=" PTR_FORMAT " based on current fp)\n", p2i(f.id()));
481 p->trace_stack_from(vframe::new_vframe(&f, ®_map, p));
482 f.pd_ps();
483 #endif // PRODUCT
484 }
485
486 }
487
488 extern "C" void pfl() {
489 // print frame layout
490 Command c("pfl");
491 JavaThread* p = JavaThread::active();
492 tty->print(" for thread: ");
493 p->print();
494 tty->cr();
495 if (p->has_last_Java_frame()) {
496 p->print_frame_layout();
497 }
498 }
499
500 #ifndef PRODUCT
501
502 extern "C" void psf() { // print stack frames
503 {
504 Command c("psf");
505 JavaThread* p = JavaThread::active();
506 tty->print(" for thread: ");
507 p->print();
508 tty->cr();
509 if (p->has_last_Java_frame()) {
510 p->trace_frames();
511 }
512 }
513 }
514
515
516 extern "C" void threads() {
517 Command c("threads");
518 Threads::print(false, true);
519 }
520
521
522 extern "C" void psd() {
523 Command c("psd");
524 SystemDictionary::print();
525 }
526
527 #endif // !PRODUCT
528
529 extern "C" void pss() { // print all stacks
530 if (Thread::current_or_null() == NULL) return;
531 Command c("pss");
532 Threads::print(true, PRODUCT_ONLY(false) NOT_PRODUCT(true));
533 }
534
535 #ifndef PRODUCT
536
537 extern "C" void debug() { // to set things up for compiler debugging
538 Command c("debug");
539 WizardMode = true;
540 PrintVMMessages = PrintCompilation = true;
541 PrintInlining = PrintAssembly = true;
542 tty->flush();
543 }
544
545
546 extern "C" void ndebug() { // undo debug()
547 Command c("ndebug");
548 PrintCompilation = false;
549 PrintInlining = PrintAssembly = false;
550 tty->flush();
551 }
552
553
554 extern "C" void flush() {
555 Command c("flush");
556 tty->flush();
557 }
558
559 extern "C" void events() {
560 Command c("events");
561 Events::print();
562 }
563
564 extern "C" Method* findm(intptr_t pc) {
565 Command c("findm");
566 nmethod* nm = CodeCache::find_nmethod((address)pc);
567 return (nm == NULL) ? (Method*)NULL : nm->method();
568 }
569
570
571 extern "C" nmethod* findnm(intptr_t addr) {
572 Command c("findnm");
573 return CodeCache::find_nmethod((address)addr);
574 }
575
576 // Another interface that isn't ambiguous in dbx.
577 // Can we someday rename the other find to hsfind?
578 extern "C" void hsfind(intptr_t x) {
579 Command c("hsfind");
580 os::print_location(tty, x, false);
581 }
582
583
584 extern "C" void find(intptr_t x) {
585 Command c("find");
586 os::print_location(tty, x, false);
587 }
588
589
590 extern "C" void findpc(intptr_t x) {
591 Command c("findpc");
592 os::print_location(tty, x, true);
593 }
594
595
596 // Need method pointer to find bcp, when not in permgen.
597 extern "C" void findbcp(intptr_t method, intptr_t bcp) {
598 Command c("findbcp");
599 Method* mh = (Method*)method;
600 if (!mh->is_native()) {
601 tty->print_cr("bci_from(%p) = %d; print_codes():",
602 mh, mh->bci_from(address(bcp)));
603 mh->print_codes_on(tty);
604 }
605 }
606
607 // int versions of all methods to avoid having to type type casts in the debugger
608
609 void pp(intptr_t p) { pp((void*)p); }
610 void pp(oop p) { pp((void*)p); }
611
612 void help() {
613 Command c("help");
614 tty->print_cr("basic");
615 tty->print_cr(" pp(void* p) - try to make sense of p");
616 tty->print_cr(" pv(intptr_t p)- ((PrintableResourceObj*) p)->print()");
617 tty->print_cr(" ps() - print current thread stack");
618 tty->print_cr(" pss() - print all thread stacks");
619 tty->print_cr(" pm(int pc) - print Method* given compiled PC");
620 tty->print_cr(" findm(intptr_t pc) - finds Method*");
621 tty->print_cr(" find(intptr_t x) - finds & prints nmethod/stub/bytecode/oop based on pointer into it");
622 tty->print_cr(" pns(void* sp, void* fp, void* pc) - print native (i.e. mixed) stack trace. E.g.");
623 tty->print_cr(" pns($sp, $rbp, $pc) on Linux/amd64 and Solaris/amd64 or");
624 tty->print_cr(" pns($sp, $ebp, $pc) on Linux/x86 or");
625 tty->print_cr(" pns($sp, 0, $pc) on Linux/ppc64 or");
626 tty->print_cr(" pns($sp + 0x7ff, 0, $pc) on Solaris/SPARC");
627 tty->print_cr(" - in gdb do 'set overload-resolution off' before calling pns()");
628 tty->print_cr(" - in dbx do 'frame 1' before calling pns()");
629
630 tty->print_cr("misc.");
631 tty->print_cr(" flush() - flushes the log file");
632 tty->print_cr(" events() - dump events from ring buffers");
633
634
635 tty->print_cr("compiler debugging");
636 tty->print_cr(" debug() - to set things up for compiler debugging");
637 tty->print_cr(" ndebug() - undo debug");
638 }
639
640 extern "C" void pns(void* sp, void* fp, void* pc) { // print native stack
641 Command c("pns");
642 static char buf[O_BUFLEN];
643 Thread* t = Thread::current_or_null();
644 // Call generic frame constructor (certain arguments may be ignored)
645 frame fr(sp, fp, pc);
646 VMError::print_native_stack(tty, fr, t, buf, sizeof(buf));
647 }
648
649 //
650 // This version of pns() will not work when called from the debugger, but is
651 // useful when called from within hotspot code. The advantages over pns()
652 // are not having to pass in any arguments, and it will work on Windows/x64.
653 //
654 // WARNING: Only intended for use when debugging. Do not leave calls to
655 // pns2() in committed source (product or debug).
656 //
657 extern "C" void pns2() { // print native stack
658 Command c("pns2");
659 static char buf[O_BUFLEN];
660 if (os::platform_print_native_stack(tty, NULL, buf, sizeof(buf))) {
661 // We have printed the native stack in platform-specific code,
662 // so nothing else to do in this case.
663 } else {
664 Thread* t = Thread::current_or_null();
665 frame fr = os::current_frame();
666 VMError::print_native_stack(tty, fr, t, buf, sizeof(buf));
667 }
668 }
669
670 #endif // !PRODUCT
671
672 //////////////////////////////////////////////////////////////////////////////
673 // Test multiple STATIC_ASSERT forms in various scopes.
674
675 #ifndef PRODUCT
676
677 // namespace scope
678 STATIC_ASSERT(true);
679 STATIC_ASSERT(true);
680 STATIC_ASSERT(1 == 1);
681 STATIC_ASSERT(0 == 0);
682
683 void test_multiple_static_assert_forms_in_function_scope() {
684 STATIC_ASSERT(true);
685 STATIC_ASSERT(true);
686 STATIC_ASSERT(0 == 0);
687 STATIC_ASSERT(1 == 1);
688 }
689
690 // class scope
691 struct TestMultipleStaticAssertFormsInClassScope {
692 STATIC_ASSERT(true);
693 STATIC_ASSERT(true);
694 STATIC_ASSERT(0 == 0);
695 STATIC_ASSERT(1 == 1);
696 };
697
698 #endif // !PRODUCT
699
700 // Support for showing register content on asserts/guarantees.
701 #ifdef CAN_SHOW_REGISTERS_ON_ASSERT
702 #ifdef _WIN32
703 typedef CONTEXT context_t;
704 #else
705 typedef ucontext_t context_t;
706 #endif
707
708 static context_t g_stored_assertion_context;
709
710 void initialize_assert_poison() {
711 char* page = os::reserve_memory(os::vm_page_size());
712 if (page) {
713 if (os::commit_memory(page, os::vm_page_size(), false) &&
714 os::protect_memory(page, os::vm_page_size(), os::MEM_PROT_NONE)) {
715 g_assert_poison = page;
716 }
717 }
718 }
719
720 static bool store_context(const void* context) {
721 if (memcpy(&g_stored_assertion_context, context, sizeof(context_t)) == false) {
722 return false;
723 }
724 #if defined(__linux) && defined(PPC64)
725 // on Linux ppc64, ucontext_t contains pointers into itself which have to be patched up
726 // after copying the context (see comment in sys/ucontext.h):
727 *((void**) &g_stored_assertion_context.uc_mcontext.regs) = &(g_stored_assertion_context.uc_mcontext.gp_regs);
728 #endif
729 return true;
730 }
731
732 bool handle_assert_poison_fault(const void* ucVoid, const void* faulting_address) {
733 if (faulting_address == g_assert_poison) {
734 // Disarm poison page.
735 os::protect_memory((char*)g_assert_poison, os::vm_page_size(), os::MEM_PROT_RWX);
736 // Store Context away.
737 if (ucVoid) {
738 const jlong my_tid = os::current_thread_id();
739 if (Atomic::cmpxchg(my_tid, &g_asserting_thread, (intx)0) == 0) {
740 if (store_context(ucVoid)) {
741 g_assertion_context = &g_stored_assertion_context;
742 }
743 }
744 }
745 return true;
746 }
747 return false;
748 }
749 #endif // CAN_SHOW_REGISTERS_ON_ASSERT
750