1 /*
2 * Copyright (c) 1997, 2010, 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 "incls/_precompiled.incl"
26 # include "incls/_frame.cpp.incl"
27
28 RegisterMap::RegisterMap(JavaThread *thread, bool update_map) {
29 _thread = thread;
30 _update_map = update_map;
31 clear();
32 debug_only(_update_for_id = NULL;)
33 #ifndef PRODUCT
34 for (int i = 0; i < reg_count ; i++ ) _location[i] = NULL;
35 #endif /* PRODUCT */
36 }
37
38 RegisterMap::RegisterMap(const RegisterMap* map) {
39 assert(map != this, "bad initialization parameter");
40 assert(map != NULL, "RegisterMap must be present");
41 _thread = map->thread();
42 _update_map = map->update_map();
43 _include_argument_oops = map->include_argument_oops();
44 debug_only(_update_for_id = map->_update_for_id;)
45 pd_initialize_from(map);
46 if (update_map()) {
47 for(int i = 0; i < location_valid_size; i++) {
48 LocationValidType bits = !update_map() ? 0 : map->_location_valid[i];
49 _location_valid[i] = bits;
50 // for whichever bits are set, pull in the corresponding map->_location
51 int j = i*location_valid_type_size;
52 while (bits != 0) {
53 if ((bits & 1) != 0) {
54 assert(0 <= j && j < reg_count, "range check");
55 _location[j] = map->_location[j];
56 }
57 bits >>= 1;
58 j += 1;
59 }
60 }
61 }
62 }
63
64 void RegisterMap::clear() {
65 set_include_argument_oops(true);
66 if (_update_map) {
67 for(int i = 0; i < location_valid_size; i++) {
68 _location_valid[i] = 0;
69 }
70 pd_clear();
71 } else {
72 pd_initialize();
73 }
74 }
75
76 #ifndef PRODUCT
77
78 void RegisterMap::print_on(outputStream* st) const {
79 st->print_cr("Register map");
80 for(int i = 0; i < reg_count; i++) {
81
82 VMReg r = VMRegImpl::as_VMReg(i);
83 intptr_t* src = (intptr_t*) location(r);
84 if (src != NULL) {
85
86 r->print_on(st);
87 st->print(" [" INTPTR_FORMAT "] = ", src);
88 if (((uintptr_t)src & (sizeof(*src)-1)) != 0) {
89 st->print_cr("<misaligned>");
90 } else {
91 st->print_cr(INTPTR_FORMAT, *src);
92 }
93 }
94 }
95 }
96
97 void RegisterMap::print() const {
98 print_on(tty);
99 }
100
101 #endif
102 // This returns the pc that if you were in the debugger you'd see. Not
103 // the idealized value in the frame object. This undoes the magic conversion
104 // that happens for deoptimized frames. In addition it makes the value the
105 // hardware would want to see in the native frame. The only user (at this point)
106 // is deoptimization. It likely no one else should ever use it.
107
108 address frame::raw_pc() const {
109 if (is_deoptimized_frame()) {
110 nmethod* nm = cb()->as_nmethod_or_null();
111 if (nm->is_method_handle_return(pc()))
112 return nm->deopt_mh_handler_begin() - pc_return_offset;
113 else
114 return nm->deopt_handler_begin() - pc_return_offset;
115 } else {
116 return (pc() - pc_return_offset);
117 }
118 }
119
120 // Change the pc in a frame object. This does not change the actual pc in
121 // actual frame. To do that use patch_pc.
122 //
123 void frame::set_pc(address newpc ) {
124 #ifdef ASSERT
125 if (_cb != NULL && _cb->is_nmethod()) {
126 assert(!((nmethod*)_cb)->is_deopt_pc(_pc), "invariant violation");
127 }
128 #endif // ASSERT
129
130 // Unsafe to use the is_deoptimzed tester after changing pc
131 _deopt_state = unknown;
132 _pc = newpc;
133 _cb = CodeCache::find_blob_unsafe(_pc);
134
135 }
136
137 // type testers
138 bool frame::is_deoptimized_frame() const {
139 assert(_deopt_state != unknown, "not answerable");
140 return _deopt_state == is_deoptimized;
141 }
142
143 bool frame::is_native_frame() const {
144 return (_cb != NULL &&
145 _cb->is_nmethod() &&
146 ((nmethod*)_cb)->is_native_method());
147 }
148
149 bool frame::is_java_frame() const {
150 if (is_interpreted_frame()) return true;
151 if (is_compiled_frame()) return true;
152 return false;
153 }
154
155
156 bool frame::is_compiled_frame() const {
157 if (_cb != NULL &&
158 _cb->is_nmethod() &&
159 ((nmethod*)_cb)->is_java_method()) {
160 return true;
161 }
162 return false;
163 }
164
165
166 bool frame::is_runtime_frame() const {
167 return (_cb != NULL && _cb->is_runtime_stub());
168 }
169
170 bool frame::is_safepoint_blob_frame() const {
171 return (_cb != NULL && _cb->is_safepoint_stub());
172 }
173
174 // testers
175
176 bool frame::is_first_java_frame() const {
177 RegisterMap map(JavaThread::current(), false); // No update
178 frame s;
179 for (s = sender(&map); !(s.is_java_frame() || s.is_first_frame()); s = s.sender(&map));
180 return s.is_first_frame();
181 }
182
183
184 bool frame::entry_frame_is_first() const {
185 return entry_frame_call_wrapper()->anchor()->last_Java_sp() == NULL;
186 }
187
188
189 bool frame::should_be_deoptimized() const {
190 if (_deopt_state == is_deoptimized ||
191 !is_compiled_frame() ) return false;
192 assert(_cb != NULL && _cb->is_nmethod(), "must be an nmethod");
193 nmethod* nm = (nmethod *)_cb;
194 if (TraceDependencies) {
195 tty->print("checking (%s) ", nm->is_marked_for_deoptimization() ? "true" : "false");
196 nm->print_value_on(tty);
197 tty->cr();
198 }
199
200 if( !nm->is_marked_for_deoptimization() )
201 return false;
202
203 // If at the return point, then the frame has already been popped, and
204 // only the return needs to be executed. Don't deoptimize here.
205 return !nm->is_at_poll_return(pc());
206 }
207
208 bool frame::can_be_deoptimized() const {
209 if (!is_compiled_frame()) return false;
210 nmethod* nm = (nmethod*)_cb;
211
212 if( !nm->can_be_deoptimized() )
213 return false;
214
215 return !nm->is_at_poll_return(pc());
216 }
217
218 void frame::deoptimize(JavaThread* thread, bool thread_is_known_safe) {
219 // Schedule deoptimization of an nmethod activation with this frame.
220
221 // Store the original pc before an patch (or request to self-deopt)
222 // in the published location of the frame.
223
224 assert(_cb != NULL && _cb->is_nmethod(), "must be");
225 nmethod* nm = (nmethod*)_cb;
226
227 // This is a fix for register window patching race
228 if (NeedsDeoptSuspend && !thread_is_known_safe) {
229
230 // It is possible especially with DeoptimizeALot/DeoptimizeRandom that
231 // we could see the frame again and ask for it to be deoptimized since
232 // it might move for a long time. That is harmless and we just ignore it.
233 if (id() == thread->must_deopt_id()) {
234 assert(thread->is_deopt_suspend(), "lost suspension");
235 return;
236 }
237
238 // We are at a safepoint so the target thread can only be
239 // in 4 states:
240 // blocked - no problem
241 // blocked_trans - no problem (i.e. could have woken up from blocked
242 // during a safepoint).
243 // native - register window pc patching race
244 // native_trans - momentary state
245 //
246 // We could just wait out a thread in native_trans to block.
247 // Then we'd have all the issues that the safepoint code has as to
248 // whether to spin or block. It isn't worth it. Just treat it like
249 // native and be done with it.
250 //
251 JavaThreadState state = thread->thread_state();
252 if (state == _thread_in_native || state == _thread_in_native_trans) {
253 // Since we are at a safepoint the target thread will stop itself
254 // before it can return to java as long as we remain at the safepoint.
255 // Therefore we can put an additional request for the thread to stop
256 // no matter what no (like a suspend). This will cause the thread
257 // to notice it needs to do the deopt on its own once it leaves native.
258 //
259 // The only reason we must do this is because on machine with register
260 // windows we have a race with patching the return address and the
261 // window coming live as the thread returns to the Java code (but still
262 // in native mode) and then blocks. It is only this top most frame
263 // that is at risk. So in truth we could add an additional check to
264 // see if this frame is one that is at risk.
265 RegisterMap map(thread, false);
266 frame at_risk = thread->last_frame().sender(&map);
267 if (id() == at_risk.id()) {
268 thread->set_must_deopt_id(id());
269 thread->set_deopt_suspend();
270 return;
271 }
272 }
273 } // NeedsDeoptSuspend
274
275
276 // If the call site is a MethodHandle call site use the MH deopt
277 // handler.
278 address deopt = nm->is_method_handle_return(pc()) ?
279 nm->deopt_mh_handler_begin() :
280 nm->deopt_handler_begin();
281
282 // Save the original pc before we patch in the new one
283 nm->set_original_pc(this, pc());
284 patch_pc(thread, deopt);
285
286 #ifdef ASSERT
287 {
288 RegisterMap map(thread, false);
289 frame check = thread->last_frame();
290 while (id() != check.id()) {
291 check = check.sender(&map);
292 }
293 assert(check.is_deoptimized_frame(), "missed deopt");
294 }
295 #endif // ASSERT
296 }
297
298 frame frame::java_sender() const {
299 RegisterMap map(JavaThread::current(), false);
300 frame s;
301 for (s = sender(&map); !(s.is_java_frame() || s.is_first_frame()); s = s.sender(&map)) ;
302 guarantee(s.is_java_frame(), "tried to get caller of first java frame");
303 return s;
304 }
305
306 frame frame::real_sender(RegisterMap* map) const {
307 frame result = sender(map);
308 while (result.is_runtime_frame()) {
309 result = result.sender(map);
310 }
311 return result;
312 }
313
314 // Note: called by profiler - NOT for current thread
315 frame frame::profile_find_Java_sender_frame(JavaThread *thread) {
316 // If we don't recognize this frame, walk back up the stack until we do
317 RegisterMap map(thread, false);
318 frame first_java_frame = frame();
319
320 // Find the first Java frame on the stack starting with input frame
321 if (is_java_frame()) {
322 // top frame is compiled frame or deoptimized frame
323 first_java_frame = *this;
324 } else if (safe_for_sender(thread)) {
325 for (frame sender_frame = sender(&map);
326 sender_frame.safe_for_sender(thread) && !sender_frame.is_first_frame();
327 sender_frame = sender_frame.sender(&map)) {
328 if (sender_frame.is_java_frame()) {
329 first_java_frame = sender_frame;
330 break;
331 }
332 }
333 }
334 return first_java_frame;
335 }
336
337 // Interpreter frames
338
339
340 void frame::interpreter_frame_set_locals(intptr_t* locs) {
341 assert(is_interpreted_frame(), "Not an interpreted frame");
342 *interpreter_frame_locals_addr() = locs;
343 }
344
345 methodOop frame::interpreter_frame_method() const {
346 assert(is_interpreted_frame(), "interpreted frame expected");
347 methodOop m = *interpreter_frame_method_addr();
348 assert(m->is_perm(), "bad methodOop in interpreter frame");
349 assert(m->is_method(), "not a methodOop");
350 return m;
351 }
352
353 void frame::interpreter_frame_set_method(methodOop method) {
354 assert(is_interpreted_frame(), "interpreted frame expected");
355 *interpreter_frame_method_addr() = method;
356 }
357
358 void frame::interpreter_frame_set_bcx(intptr_t bcx) {
359 assert(is_interpreted_frame(), "Not an interpreted frame");
360 if (ProfileInterpreter) {
361 bool formerly_bci = is_bci(interpreter_frame_bcx());
362 bool is_now_bci = is_bci(bcx);
363 *interpreter_frame_bcx_addr() = bcx;
364
365 intptr_t mdx = interpreter_frame_mdx();
366
367 if (mdx != 0) {
368 if (formerly_bci) {
369 if (!is_now_bci) {
370 // The bcx was just converted from bci to bcp.
371 // Convert the mdx in parallel.
372 methodDataOop mdo = interpreter_frame_method()->method_data();
373 assert(mdo != NULL, "");
374 int mdi = mdx - 1; // We distinguish valid mdi from zero by adding one.
375 address mdp = mdo->di_to_dp(mdi);
376 interpreter_frame_set_mdx((intptr_t)mdp);
377 }
378 } else {
379 if (is_now_bci) {
380 // The bcx was just converted from bcp to bci.
381 // Convert the mdx in parallel.
382 methodDataOop mdo = interpreter_frame_method()->method_data();
383 assert(mdo != NULL, "");
384 int mdi = mdo->dp_to_di((address)mdx);
385 interpreter_frame_set_mdx((intptr_t)mdi + 1); // distinguish valid from 0.
386 }
387 }
388 }
389 } else {
390 *interpreter_frame_bcx_addr() = bcx;
391 }
392 }
393
394 jint frame::interpreter_frame_bci() const {
395 assert(is_interpreted_frame(), "interpreted frame expected");
396 intptr_t bcx = interpreter_frame_bcx();
397 return is_bci(bcx) ? bcx : interpreter_frame_method()->bci_from((address)bcx);
398 }
399
400 void frame::interpreter_frame_set_bci(jint bci) {
401 assert(is_interpreted_frame(), "interpreted frame expected");
402 assert(!is_bci(interpreter_frame_bcx()), "should not set bci during GC");
403 interpreter_frame_set_bcx((intptr_t)interpreter_frame_method()->bcp_from(bci));
404 }
405
406 address frame::interpreter_frame_bcp() const {
407 assert(is_interpreted_frame(), "interpreted frame expected");
408 intptr_t bcx = interpreter_frame_bcx();
409 return is_bci(bcx) ? interpreter_frame_method()->bcp_from(bcx) : (address)bcx;
410 }
411
412 void frame::interpreter_frame_set_bcp(address bcp) {
413 assert(is_interpreted_frame(), "interpreted frame expected");
414 assert(!is_bci(interpreter_frame_bcx()), "should not set bcp during GC");
415 interpreter_frame_set_bcx((intptr_t)bcp);
416 }
417
418 void frame::interpreter_frame_set_mdx(intptr_t mdx) {
419 assert(is_interpreted_frame(), "Not an interpreted frame");
420 assert(ProfileInterpreter, "must be profiling interpreter");
421 *interpreter_frame_mdx_addr() = mdx;
422 }
423
424 address frame::interpreter_frame_mdp() const {
425 assert(ProfileInterpreter, "must be profiling interpreter");
426 assert(is_interpreted_frame(), "interpreted frame expected");
427 intptr_t bcx = interpreter_frame_bcx();
428 intptr_t mdx = interpreter_frame_mdx();
429
430 assert(!is_bci(bcx), "should not access mdp during GC");
431 return (address)mdx;
432 }
433
434 void frame::interpreter_frame_set_mdp(address mdp) {
435 assert(is_interpreted_frame(), "interpreted frame expected");
436 if (mdp == NULL) {
437 // Always allow the mdp to be cleared.
438 interpreter_frame_set_mdx((intptr_t)mdp);
439 }
440 intptr_t bcx = interpreter_frame_bcx();
441 assert(!is_bci(bcx), "should not set mdp during GC");
442 interpreter_frame_set_mdx((intptr_t)mdp);
443 }
444
445 BasicObjectLock* frame::next_monitor_in_interpreter_frame(BasicObjectLock* current) const {
446 assert(is_interpreted_frame(), "Not an interpreted frame");
447 #ifdef ASSERT
448 interpreter_frame_verify_monitor(current);
449 #endif
450 BasicObjectLock* next = (BasicObjectLock*) (((intptr_t*) current) + interpreter_frame_monitor_size());
451 return next;
452 }
453
454 BasicObjectLock* frame::previous_monitor_in_interpreter_frame(BasicObjectLock* current) const {
455 assert(is_interpreted_frame(), "Not an interpreted frame");
456 #ifdef ASSERT
457 // // This verification needs to be checked before being enabled
458 // interpreter_frame_verify_monitor(current);
459 #endif
460 BasicObjectLock* previous = (BasicObjectLock*) (((intptr_t*) current) - interpreter_frame_monitor_size());
461 return previous;
462 }
463
464 // Interpreter locals and expression stack locations.
465
466 intptr_t* frame::interpreter_frame_local_at(int index) const {
467 const int n = Interpreter::local_offset_in_bytes(index)/wordSize;
468 return &((*interpreter_frame_locals_addr())[n]);
469 }
470
471 intptr_t* frame::interpreter_frame_expression_stack_at(jint offset) const {
472 const int i = offset * interpreter_frame_expression_stack_direction();
473 const int n = i * Interpreter::stackElementWords;
474 return &(interpreter_frame_expression_stack()[n]);
475 }
476
477 jint frame::interpreter_frame_expression_stack_size() const {
478 // Number of elements on the interpreter expression stack
479 // Callers should span by stackElementWords
480 int element_size = Interpreter::stackElementWords;
481 if (frame::interpreter_frame_expression_stack_direction() < 0) {
482 return (interpreter_frame_expression_stack() -
483 interpreter_frame_tos_address() + 1)/element_size;
484 } else {
485 return (interpreter_frame_tos_address() -
486 interpreter_frame_expression_stack() + 1)/element_size;
487 }
488 }
489
490
491 // (frame::interpreter_frame_sender_sp accessor is in frame_<arch>.cpp)
492
493 const char* frame::print_name() const {
494 if (is_native_frame()) return "Native";
495 if (is_interpreted_frame()) return "Interpreted";
496 if (is_compiled_frame()) {
497 if (is_deoptimized_frame()) return "Deoptimized";
498 return "Compiled";
499 }
500 if (sp() == NULL) return "Empty";
501 return "C";
502 }
503
504 void frame::print_value_on(outputStream* st, JavaThread *thread) const {
505 NOT_PRODUCT(address begin = pc()-40;)
506 NOT_PRODUCT(address end = NULL;)
507
508 st->print("%s frame (sp=" INTPTR_FORMAT " unextended sp=" INTPTR_FORMAT, print_name(), sp(), unextended_sp());
509 if (sp() != NULL)
510 st->print(", fp=" INTPTR_FORMAT ", pc=" INTPTR_FORMAT, fp(), pc());
511
512 if (StubRoutines::contains(pc())) {
513 st->print_cr(")");
514 st->print("(");
515 StubCodeDesc* desc = StubCodeDesc::desc_for(pc());
516 st->print("~Stub::%s", desc->name());
517 NOT_PRODUCT(begin = desc->begin(); end = desc->end();)
518 } else if (Interpreter::contains(pc())) {
519 st->print_cr(")");
520 st->print("(");
521 InterpreterCodelet* desc = Interpreter::codelet_containing(pc());
522 if (desc != NULL) {
523 st->print("~");
524 desc->print();
525 NOT_PRODUCT(begin = desc->code_begin(); end = desc->code_end();)
526 } else {
527 st->print("~interpreter");
528 }
529 }
530 st->print_cr(")");
531
532 if (_cb != NULL) {
533 st->print(" ");
534 _cb->print_value_on(st);
535 st->cr();
536 #ifndef PRODUCT
537 if (end == NULL) {
538 begin = _cb->instructions_begin();
539 end = _cb->instructions_end();
540 }
541 #endif
542 }
543 NOT_PRODUCT(if (WizardMode && Verbose) Disassembler::decode(begin, end);)
544 }
545
546
547 void frame::print_on(outputStream* st) const {
548 print_value_on(st,NULL);
549 if (is_interpreted_frame()) {
550 interpreter_frame_print_on(st);
551 }
552 }
553
554
555 void frame::interpreter_frame_print_on(outputStream* st) const {
556 #ifndef PRODUCT
557 assert(is_interpreted_frame(), "Not an interpreted frame");
558 jint i;
559 for (i = 0; i < interpreter_frame_method()->max_locals(); i++ ) {
560 intptr_t x = *interpreter_frame_local_at(i);
561 st->print(" - local [" INTPTR_FORMAT "]", x);
562 st->fill_to(23);
563 st->print_cr("; #%d", i);
564 }
565 for (i = interpreter_frame_expression_stack_size() - 1; i >= 0; --i ) {
566 intptr_t x = *interpreter_frame_expression_stack_at(i);
567 st->print(" - stack [" INTPTR_FORMAT "]", x);
568 st->fill_to(23);
569 st->print_cr("; #%d", i);
570 }
571 // locks for synchronization
572 for (BasicObjectLock* current = interpreter_frame_monitor_end();
573 current < interpreter_frame_monitor_begin();
574 current = next_monitor_in_interpreter_frame(current)) {
575 st->print(" - obj [");
576 current->obj()->print_value_on(st);
577 st->print_cr("]");
578 st->print(" - lock [");
579 current->lock()->print_on(st);
580 st->print_cr("]");
581 }
582 // monitor
583 st->print_cr(" - monitor[" INTPTR_FORMAT "]", interpreter_frame_monitor_begin());
584 // bcp
585 st->print(" - bcp [" INTPTR_FORMAT "]", interpreter_frame_bcp());
586 st->fill_to(23);
587 st->print_cr("; @%d", interpreter_frame_bci());
588 // locals
589 st->print_cr(" - locals [" INTPTR_FORMAT "]", interpreter_frame_local_at(0));
590 // method
591 st->print(" - method [" INTPTR_FORMAT "]", (address)interpreter_frame_method());
592 st->fill_to(23);
593 st->print("; ");
594 interpreter_frame_method()->print_name(st);
595 st->cr();
596 #endif
597 }
598
599 // Return whether the frame is in the VM or os indicating a Hotspot problem.
600 // Otherwise, it's likely a bug in the native library that the Java code calls,
601 // hopefully indicating where to submit bugs.
602 static void print_C_frame(outputStream* st, char* buf, int buflen, address pc) {
603 // C/C++ frame
604 bool in_vm = os::address_is_in_vm(pc);
605 st->print(in_vm ? "V" : "C");
606
607 int offset;
608 bool found;
609
610 // libname
611 found = os::dll_address_to_library_name(pc, buf, buflen, &offset);
612 if (found) {
613 // skip directory names
614 const char *p1, *p2;
615 p1 = buf;
616 int len = (int)strlen(os::file_separator());
617 while ((p2 = strstr(p1, os::file_separator())) != NULL) p1 = p2 + len;
618 st->print(" [%s+0x%x]", p1, offset);
619 } else {
620 st->print(" " PTR_FORMAT, pc);
621 }
622
623 // function name - os::dll_address_to_function_name() may return confusing
624 // names if pc is within jvm.dll or libjvm.so, because JVM only has
625 // JVM_xxxx and a few other symbols in the dynamic symbol table. Do this
626 // only for native libraries.
627 if (!in_vm) {
628 found = os::dll_address_to_function_name(pc, buf, buflen, &offset);
629
630 if (found) {
631 st->print(" %s+0x%x", buf, offset);
632 }
633 }
634 }
635
636 // frame::print_on_error() is called by fatal error handler. Notice that we may
637 // crash inside this function if stack frame is corrupted. The fatal error
638 // handler can catch and handle the crash. Here we assume the frame is valid.
639 //
640 // First letter indicates type of the frame:
641 // J: Java frame (compiled)
642 // j: Java frame (interpreted)
643 // V: VM frame (C/C++)
644 // v: Other frames running VM generated code (e.g. stubs, adapters, etc.)
645 // C: C/C++ frame
646 //
647 // We don't need detailed frame type as that in frame::print_name(). "C"
648 // suggests the problem is in user lib; everything else is likely a VM bug.
649
650 void frame::print_on_error(outputStream* st, char* buf, int buflen, bool verbose) const {
651 if (_cb != NULL) {
652 if (Interpreter::contains(pc())) {
653 methodOop m = this->interpreter_frame_method();
654 if (m != NULL) {
655 m->name_and_sig_as_C_string(buf, buflen);
656 st->print("j %s", buf);
657 st->print("+%d", this->interpreter_frame_bci());
658 } else {
659 st->print("j " PTR_FORMAT, pc());
660 }
661 } else if (StubRoutines::contains(pc())) {
662 StubCodeDesc* desc = StubCodeDesc::desc_for(pc());
663 if (desc != NULL) {
664 st->print("v ~StubRoutines::%s", desc->name());
665 } else {
666 st->print("v ~StubRoutines::" PTR_FORMAT, pc());
667 }
668 } else if (_cb->is_buffer_blob()) {
669 st->print("v ~BufferBlob::%s", ((BufferBlob *)_cb)->name());
670 } else if (_cb->is_nmethod()) {
671 methodOop m = ((nmethod *)_cb)->method();
672 if (m != NULL) {
673 m->name_and_sig_as_C_string(buf, buflen);
674 st->print("J %s", buf);
675 } else {
676 st->print("J " PTR_FORMAT, pc());
677 }
678 } else if (_cb->is_runtime_stub()) {
679 st->print("v ~RuntimeStub::%s", ((RuntimeStub *)_cb)->name());
680 } else if (_cb->is_deoptimization_stub()) {
681 st->print("v ~DeoptimizationBlob");
682 } else if (_cb->is_exception_stub()) {
683 st->print("v ~ExceptionBlob");
684 } else if (_cb->is_safepoint_stub()) {
685 st->print("v ~SafepointBlob");
686 } else {
687 st->print("v blob " PTR_FORMAT, pc());
688 }
689 } else {
690 print_C_frame(st, buf, buflen, pc());
691 }
692 }
693
694
695 /*
696 The interpreter_frame_expression_stack_at method in the case of SPARC needs the
697 max_stack value of the method in order to compute the expression stack address.
698 It uses the methodOop in order to get the max_stack value but during GC this
699 methodOop value saved on the frame is changed by reverse_and_push and hence cannot
700 be used. So we save the max_stack value in the FrameClosure object and pass it
701 down to the interpreter_frame_expression_stack_at method
702 */
703 class InterpreterFrameClosure : public OffsetClosure {
704 private:
705 frame* _fr;
706 OopClosure* _f;
707 int _max_locals;
708 int _max_stack;
709
710 public:
711 InterpreterFrameClosure(frame* fr, int max_locals, int max_stack,
712 OopClosure* f) {
713 _fr = fr;
714 _max_locals = max_locals;
715 _max_stack = max_stack;
716 _f = f;
717 }
718
719 void offset_do(int offset) {
720 oop* addr;
721 if (offset < _max_locals) {
722 addr = (oop*) _fr->interpreter_frame_local_at(offset);
723 assert((intptr_t*)addr >= _fr->sp(), "must be inside the frame");
724 _f->do_oop(addr);
725 } else {
726 addr = (oop*) _fr->interpreter_frame_expression_stack_at((offset - _max_locals));
727 // In case of exceptions, the expression stack is invalid and the esp will be reset to express
728 // this condition. Therefore, we call f only if addr is 'inside' the stack (i.e., addr >= esp for Intel).
729 bool in_stack;
730 if (frame::interpreter_frame_expression_stack_direction() > 0) {
731 in_stack = (intptr_t*)addr <= _fr->interpreter_frame_tos_address();
732 } else {
733 in_stack = (intptr_t*)addr >= _fr->interpreter_frame_tos_address();
734 }
735 if (in_stack) {
736 _f->do_oop(addr);
737 }
738 }
739 }
740
741 int max_locals() { return _max_locals; }
742 frame* fr() { return _fr; }
743 };
744
745
746 class InterpretedArgumentOopFinder: public SignatureInfo {
747 private:
748 OopClosure* _f; // Closure to invoke
749 int _offset; // TOS-relative offset, decremented with each argument
750 bool _has_receiver; // true if the callee has a receiver
751 frame* _fr;
752
753 void set(int size, BasicType type) {
754 _offset -= size;
755 if (type == T_OBJECT || type == T_ARRAY) oop_offset_do();
756 }
757
758 void oop_offset_do() {
759 oop* addr;
760 addr = (oop*)_fr->interpreter_frame_tos_at(_offset);
761 _f->do_oop(addr);
762 }
763
764 public:
765 InterpretedArgumentOopFinder(symbolHandle signature, bool has_receiver, frame* fr, OopClosure* f) : SignatureInfo(signature), _has_receiver(has_receiver) {
766 // compute size of arguments
767 int args_size = ArgumentSizeComputer(signature).size() + (has_receiver ? 1 : 0);
768 assert(!fr->is_interpreted_frame() ||
769 args_size <= fr->interpreter_frame_expression_stack_size(),
770 "args cannot be on stack anymore");
771 // initialize InterpretedArgumentOopFinder
772 _f = f;
773 _fr = fr;
774 _offset = args_size;
775 }
776
777 void oops_do() {
778 if (_has_receiver) {
779 --_offset;
780 oop_offset_do();
781 }
782 iterate_parameters();
783 }
784 };
785
786
787 // Entry frame has following form (n arguments)
788 // +-----------+
789 // sp -> | last arg |
790 // +-----------+
791 // : ::: :
792 // +-----------+
793 // (sp+n)->| first arg|
794 // +-----------+
795
796
797
798 // visits and GC's all the arguments in entry frame
799 class EntryFrameOopFinder: public SignatureInfo {
800 private:
801 bool _is_static;
802 int _offset;
803 frame* _fr;
804 OopClosure* _f;
805
806 void set(int size, BasicType type) {
807 assert (_offset >= 0, "illegal offset");
808 if (type == T_OBJECT || type == T_ARRAY) oop_at_offset_do(_offset);
809 _offset -= size;
810 }
811
812 void oop_at_offset_do(int offset) {
813 assert (offset >= 0, "illegal offset");
814 oop* addr = (oop*) _fr->entry_frame_argument_at(offset);
815 _f->do_oop(addr);
816 }
817
818 public:
819 EntryFrameOopFinder(frame* frame, symbolHandle signature, bool is_static) : SignatureInfo(signature) {
820 _f = NULL; // will be set later
821 _fr = frame;
822 _is_static = is_static;
823 _offset = ArgumentSizeComputer(signature).size() - 1; // last parameter is at index 0
824 }
825
826 void arguments_do(OopClosure* f) {
827 _f = f;
828 if (!_is_static) oop_at_offset_do(_offset+1); // do the receiver
829 iterate_parameters();
830 }
831
832 };
833
834 oop* frame::interpreter_callee_receiver_addr(symbolHandle signature) {
835 ArgumentSizeComputer asc(signature);
836 int size = asc.size();
837 return (oop *)interpreter_frame_tos_at(size);
838 }
839
840
841 void frame::oops_interpreted_do(OopClosure* f, const RegisterMap* map, bool query_oop_map_cache) {
842 assert(is_interpreted_frame(), "Not an interpreted frame");
843 assert(map != NULL, "map must be set");
844 Thread *thread = Thread::current();
845 methodHandle m (thread, interpreter_frame_method());
846 jint bci = interpreter_frame_bci();
847
848 assert(Universe::heap()->is_in(m()), "must be valid oop");
849 assert(m->is_method(), "checking frame value");
850 assert((m->is_native() && bci == 0) || (!m->is_native() && bci >= 0 && bci < m->code_size()), "invalid bci value");
851
852 // Handle the monitor elements in the activation
853 for (
854 BasicObjectLock* current = interpreter_frame_monitor_end();
855 current < interpreter_frame_monitor_begin();
856 current = next_monitor_in_interpreter_frame(current)
857 ) {
858 #ifdef ASSERT
859 interpreter_frame_verify_monitor(current);
860 #endif
861 current->oops_do(f);
862 }
863
864 // process fixed part
865 f->do_oop((oop*)interpreter_frame_method_addr());
866 f->do_oop((oop*)interpreter_frame_cache_addr());
867
868 // Hmm what about the mdp?
869 #ifdef CC_INTERP
870 // Interpreter frame in the midst of a call have a methodOop within the
871 // object.
872 interpreterState istate = get_interpreterState();
873 if (istate->msg() == BytecodeInterpreter::call_method) {
874 f->do_oop((oop*)&istate->_result._to_call._callee);
875 }
876
877 #endif /* CC_INTERP */
878
879 if (m->is_native()) {
880 #ifdef CC_INTERP
881 f->do_oop((oop*)&istate->_oop_temp);
882 #else
883 f->do_oop((oop*)( fp() + interpreter_frame_oop_temp_offset ));
884 #endif /* CC_INTERP */
885 }
886
887 int max_locals = m->is_native() ? m->size_of_parameters() : m->max_locals();
888
889 symbolHandle signature;
890 bool has_receiver = false;
891
892 // Process a callee's arguments if we are at a call site
893 // (i.e., if we are at an invoke bytecode)
894 // This is used sometimes for calling into the VM, not for another
895 // interpreted or compiled frame.
896 if (!m->is_native()) {
897 Bytecode_invoke *call = Bytecode_invoke_at_check(m, bci);
898 if (call != NULL) {
899 signature = symbolHandle(thread, call->signature());
900 has_receiver = call->has_receiver();
901 if (map->include_argument_oops() &&
902 interpreter_frame_expression_stack_size() > 0) {
903 ResourceMark rm(thread); // is this right ???
904 // we are at a call site & the expression stack is not empty
905 // => process callee's arguments
906 //
907 // Note: The expression stack can be empty if an exception
908 // occurred during method resolution/execution. In all
909 // cases we empty the expression stack completely be-
910 // fore handling the exception (the exception handling
911 // code in the interpreter calls a blocking runtime
912 // routine which can cause this code to be executed).
913 // (was bug gri 7/27/98)
914 oops_interpreted_arguments_do(signature, has_receiver, f);
915 }
916 }
917 }
918
919 InterpreterFrameClosure blk(this, max_locals, m->max_stack(), f);
920
921 // process locals & expression stack
922 InterpreterOopMap mask;
923 if (query_oop_map_cache) {
924 m->mask_for(bci, &mask);
925 } else {
926 OopMapCache::compute_one_oop_map(m, bci, &mask);
927 }
928 mask.iterate_oop(&blk);
929 }
930
931
932 void frame::oops_interpreted_arguments_do(symbolHandle signature, bool has_receiver, OopClosure* f) {
933 InterpretedArgumentOopFinder finder(signature, has_receiver, this, f);
934 finder.oops_do();
935 }
936
937 void frame::oops_code_blob_do(OopClosure* f, CodeBlobClosure* cf, const RegisterMap* reg_map) {
938 assert(_cb != NULL, "sanity check");
939 if (_cb->oop_maps() != NULL) {
940 OopMapSet::oops_do(this, reg_map, f);
941
942 // Preserve potential arguments for a callee. We handle this by dispatching
943 // on the codeblob. For c2i, we do
944 if (reg_map->include_argument_oops()) {
945 _cb->preserve_callee_argument_oops(*this, reg_map, f);
946 }
947 }
948 // In cases where perm gen is collected, GC will want to mark
949 // oops referenced from nmethods active on thread stacks so as to
950 // prevent them from being collected. However, this visit should be
951 // restricted to certain phases of the collection only. The
952 // closure decides how it wants nmethods to be traced.
953 if (cf != NULL)
954 cf->do_code_blob(_cb);
955 }
956
957 class CompiledArgumentOopFinder: public SignatureInfo {
958 protected:
959 OopClosure* _f;
960 int _offset; // the current offset, incremented with each argument
961 bool _has_receiver; // true if the callee has a receiver
962 frame _fr;
963 RegisterMap* _reg_map;
964 int _arg_size;
965 VMRegPair* _regs; // VMReg list of arguments
966
967 void set(int size, BasicType type) {
968 if (type == T_OBJECT || type == T_ARRAY) handle_oop_offset();
969 _offset += size;
970 }
971
972 virtual void handle_oop_offset() {
973 // Extract low order register number from register array.
974 // In LP64-land, the high-order bits are valid but unhelpful.
975 VMReg reg = _regs[_offset].first();
976 oop *loc = _fr.oopmapreg_to_location(reg, _reg_map);
977 _f->do_oop(loc);
978 }
979
980 public:
981 CompiledArgumentOopFinder(symbolHandle signature, bool has_receiver, OopClosure* f, frame fr, const RegisterMap* reg_map)
982 : SignatureInfo(signature) {
983
984 // initialize CompiledArgumentOopFinder
985 _f = f;
986 _offset = 0;
987 _has_receiver = has_receiver;
988 _fr = fr;
989 _reg_map = (RegisterMap*)reg_map;
990 _arg_size = ArgumentSizeComputer(signature).size() + (has_receiver ? 1 : 0);
991
992 int arg_size;
993 _regs = SharedRuntime::find_callee_arguments(signature(), has_receiver, &arg_size);
994 assert(arg_size == _arg_size, "wrong arg size");
995 }
996
997 void oops_do() {
998 if (_has_receiver) {
999 handle_oop_offset();
1000 _offset++;
1001 }
1002 iterate_parameters();
1003 }
1004 };
1005
1006 void frame::oops_compiled_arguments_do(symbolHandle signature, bool has_receiver, const RegisterMap* reg_map, OopClosure* f) {
1007 ResourceMark rm;
1008 CompiledArgumentOopFinder finder(signature, has_receiver, f, *this, reg_map);
1009 finder.oops_do();
1010 }
1011
1012
1013 // Get receiver out of callers frame, i.e. find parameter 0 in callers
1014 // frame. Consult ADLC for where parameter 0 is to be found. Then
1015 // check local reg_map for it being a callee-save register or argument
1016 // register, both of which are saved in the local frame. If not found
1017 // there, it must be an in-stack argument of the caller.
1018 // Note: caller.sp() points to callee-arguments
1019 oop frame::retrieve_receiver(RegisterMap* reg_map) {
1020 frame caller = *this;
1021
1022 // First consult the ADLC on where it puts parameter 0 for this signature.
1023 VMReg reg = SharedRuntime::name_for_receiver();
1024 oop r = *caller.oopmapreg_to_location(reg, reg_map);
1025 assert( Universe::heap()->is_in_or_null(r), "bad receiver" );
1026 return r;
1027 }
1028
1029
1030 oop* frame::oopmapreg_to_location(VMReg reg, const RegisterMap* reg_map) const {
1031 if(reg->is_reg()) {
1032 // If it is passed in a register, it got spilled in the stub frame.
1033 return (oop *)reg_map->location(reg);
1034 } else {
1035 int sp_offset_in_bytes = reg->reg2stack() * VMRegImpl::stack_slot_size;
1036 return (oop*)(((address)unextended_sp()) + sp_offset_in_bytes);
1037 }
1038 }
1039
1040 BasicLock* frame::compiled_synchronized_native_monitor(nmethod* nm) {
1041 if (nm == NULL) {
1042 assert(_cb != NULL && _cb->is_nmethod() &&
1043 nm->method()->is_native() &&
1044 nm->method()->is_synchronized(),
1045 "should not call this otherwise");
1046 nm = (nmethod*) _cb;
1047 }
1048 int byte_offset = in_bytes(nm->compiled_synchronized_native_basic_lock_sp_offset());
1049 assert(byte_offset >= 0, "should not see invalid offset");
1050 return (BasicLock*) &sp()[byte_offset / wordSize];
1051 }
1052
1053 oop frame::compiled_synchronized_native_monitor_owner(nmethod* nm) {
1054 if (nm == NULL) {
1055 assert(_cb != NULL && _cb->is_nmethod() &&
1056 nm->method()->is_native() &&
1057 nm->method()->is_synchronized(),
1058 "should not call this otherwise");
1059 nm = (nmethod*) _cb;
1060 }
1061 int byte_offset = in_bytes(nm->compiled_synchronized_native_basic_lock_owner_sp_offset());
1062 assert(byte_offset >= 0, "should not see invalid offset");
1063 oop owner = ((oop*) sp())[byte_offset / wordSize];
1064 assert( Universe::heap()->is_in(owner), "bad receiver" );
1065 return owner;
1066 }
1067
1068 void frame::oops_entry_do(OopClosure* f, const RegisterMap* map) {
1069 assert(map != NULL, "map must be set");
1070 if (map->include_argument_oops()) {
1071 // must collect argument oops, as nobody else is doing it
1072 Thread *thread = Thread::current();
1073 methodHandle m (thread, entry_frame_call_wrapper()->callee_method());
1074 symbolHandle signature (thread, m->signature());
1075 EntryFrameOopFinder finder(this, signature, m->is_static());
1076 finder.arguments_do(f);
1077 }
1078 // Traverse the Handle Block saved in the entry frame
1079 entry_frame_call_wrapper()->oops_do(f);
1080 }
1081
1082
1083 void frame::oops_do_internal(OopClosure* f, CodeBlobClosure* cf, RegisterMap* map, bool use_interpreter_oop_map_cache) {
1084 #ifndef PRODUCT
1085 // simulate GC crash here to dump java thread in error report
1086 if (CrashGCForDumpingJavaThread) {
1087 char *t = NULL;
1088 *t = 'c';
1089 }
1090 #endif
1091 if (is_interpreted_frame()) {
1092 oops_interpreted_do(f, map, use_interpreter_oop_map_cache);
1093 } else if (is_entry_frame()) {
1094 oops_entry_do(f, map);
1095 } else if (CodeCache::contains(pc())) {
1096 oops_code_blob_do(f, cf, map);
1097 } else {
1098 ShouldNotReachHere();
1099 }
1100 }
1101
1102 void frame::nmethods_do(CodeBlobClosure* cf) {
1103 if (_cb != NULL && _cb->is_nmethod()) {
1104 cf->do_code_blob(_cb);
1105 }
1106 }
1107
1108
1109 void frame::gc_prologue() {
1110 if (is_interpreted_frame()) {
1111 // set bcx to bci to become methodOop position independent during GC
1112 interpreter_frame_set_bcx(interpreter_frame_bci());
1113 }
1114 }
1115
1116
1117 void frame::gc_epilogue() {
1118 if (is_interpreted_frame()) {
1119 // set bcx back to bcp for interpreter
1120 interpreter_frame_set_bcx((intptr_t)interpreter_frame_bcp());
1121 }
1122 // call processor specific epilog function
1123 pd_gc_epilog();
1124 }
1125
1126
1127 # ifdef ENABLE_ZAP_DEAD_LOCALS
1128
1129 void frame::CheckValueClosure::do_oop(oop* p) {
1130 if (CheckOopishValues && Universe::heap()->is_in_reserved(*p)) {
1131 warning("value @ " INTPTR_FORMAT " looks oopish (" INTPTR_FORMAT ") (thread = " INTPTR_FORMAT ")", p, (address)*p, Thread::current());
1132 }
1133 }
1134 frame::CheckValueClosure frame::_check_value;
1135
1136
1137 void frame::CheckOopClosure::do_oop(oop* p) {
1138 if (*p != NULL && !(*p)->is_oop()) {
1139 warning("value @ " INTPTR_FORMAT " should be an oop (" INTPTR_FORMAT ") (thread = " INTPTR_FORMAT ")", p, (address)*p, Thread::current());
1140 }
1141 }
1142 frame::CheckOopClosure frame::_check_oop;
1143
1144 void frame::check_derived_oop(oop* base, oop* derived) {
1145 _check_oop.do_oop(base);
1146 }
1147
1148
1149 void frame::ZapDeadClosure::do_oop(oop* p) {
1150 if (TraceZapDeadLocals) tty->print_cr("zapping @ " INTPTR_FORMAT " containing " INTPTR_FORMAT, p, (address)*p);
1151 // Need cast because on _LP64 the conversion to oop is ambiguous. Constant
1152 // can be either long or int.
1153 *p = (oop)(int)0xbabebabe;
1154 }
1155 frame::ZapDeadClosure frame::_zap_dead;
1156
1157 void frame::zap_dead_locals(JavaThread* thread, const RegisterMap* map) {
1158 assert(thread == Thread::current(), "need to synchronize to do this to another thread");
1159 // Tracing - part 1
1160 if (TraceZapDeadLocals) {
1161 ResourceMark rm(thread);
1162 tty->print_cr("--------------------------------------------------------------------------------");
1163 tty->print("Zapping dead locals in ");
1164 print_on(tty);
1165 tty->cr();
1166 }
1167 // Zapping
1168 if (is_entry_frame ()) zap_dead_entry_locals (thread, map);
1169 else if (is_interpreted_frame()) zap_dead_interpreted_locals(thread, map);
1170 else if (is_compiled_frame()) zap_dead_compiled_locals (thread, map);
1171
1172 else
1173 // could be is_runtime_frame
1174 // so remove error: ShouldNotReachHere();
1175 ;
1176 // Tracing - part 2
1177 if (TraceZapDeadLocals) {
1178 tty->cr();
1179 }
1180 }
1181
1182
1183 void frame::zap_dead_interpreted_locals(JavaThread *thread, const RegisterMap* map) {
1184 // get current interpreter 'pc'
1185 assert(is_interpreted_frame(), "Not an interpreted frame");
1186 methodOop m = interpreter_frame_method();
1187 int bci = interpreter_frame_bci();
1188
1189 int max_locals = m->is_native() ? m->size_of_parameters() : m->max_locals();
1190
1191 // process dynamic part
1192 InterpreterFrameClosure value_blk(this, max_locals, m->max_stack(),
1193 &_check_value);
1194 InterpreterFrameClosure oop_blk(this, max_locals, m->max_stack(),
1195 &_check_oop );
1196 InterpreterFrameClosure dead_blk(this, max_locals, m->max_stack(),
1197 &_zap_dead );
1198
1199 // get frame map
1200 InterpreterOopMap mask;
1201 m->mask_for(bci, &mask);
1202 mask.iterate_all( &oop_blk, &value_blk, &dead_blk);
1203 }
1204
1205
1206 void frame::zap_dead_compiled_locals(JavaThread* thread, const RegisterMap* reg_map) {
1207
1208 ResourceMark rm(thread);
1209 assert(_cb != NULL, "sanity check");
1210 if (_cb->oop_maps() != NULL) {
1211 OopMapSet::all_do(this, reg_map, &_check_oop, check_derived_oop, &_check_value);
1212 }
1213 }
1214
1215
1216 void frame::zap_dead_entry_locals(JavaThread*, const RegisterMap*) {
1217 if (TraceZapDeadLocals) warning("frame::zap_dead_entry_locals unimplemented");
1218 }
1219
1220
1221 void frame::zap_dead_deoptimized_locals(JavaThread*, const RegisterMap*) {
1222 if (TraceZapDeadLocals) warning("frame::zap_dead_deoptimized_locals unimplemented");
1223 }
1224
1225 # endif // ENABLE_ZAP_DEAD_LOCALS
1226
1227 void frame::verify(const RegisterMap* map) {
1228 // for now make sure receiver type is correct
1229 if (is_interpreted_frame()) {
1230 methodOop method = interpreter_frame_method();
1231 guarantee(method->is_method(), "method is wrong in frame::verify");
1232 if (!method->is_static()) {
1233 // fetch the receiver
1234 oop* p = (oop*) interpreter_frame_local_at(0);
1235 // make sure we have the right receiver type
1236 }
1237 }
1238 COMPILER2_PRESENT(assert(DerivedPointerTable::is_empty(), "must be empty before verify");)
1239 oops_do_internal(&VerifyOopClosure::verify_oop, NULL, (RegisterMap*)map, false);
1240 }
1241
1242
1243 #ifdef ASSERT
1244 bool frame::verify_return_pc(address x) {
1245 if (StubRoutines::returns_to_call_stub(x)) {
1246 return true;
1247 }
1248 if (CodeCache::contains(x)) {
1249 return true;
1250 }
1251 if (Interpreter::contains(x)) {
1252 return true;
1253 }
1254 return false;
1255 }
1256 #endif
1257
1258
1259 #ifdef ASSERT
1260 void frame::interpreter_frame_verify_monitor(BasicObjectLock* value) const {
1261 assert(is_interpreted_frame(), "Not an interpreted frame");
1262 // verify that the value is in the right part of the frame
1263 address low_mark = (address) interpreter_frame_monitor_end();
1264 address high_mark = (address) interpreter_frame_monitor_begin();
1265 address current = (address) value;
1266
1267 const int monitor_size = frame::interpreter_frame_monitor_size();
1268 guarantee((high_mark - current) % monitor_size == 0 , "Misaligned top of BasicObjectLock*");
1269 guarantee( high_mark > current , "Current BasicObjectLock* higher than high_mark");
1270
1271 guarantee((current - low_mark) % monitor_size == 0 , "Misaligned bottom of BasicObjectLock*");
1272 guarantee( current >= low_mark , "Current BasicObjectLock* below than low_mark");
1273 }
1274 #endif
1275
1276
1277 //-----------------------------------------------------------------------------------
1278 // StackFrameStream implementation
1279
1280 StackFrameStream::StackFrameStream(JavaThread *thread, bool update) : _reg_map(thread, update) {
1281 assert(thread->has_last_Java_frame(), "sanity check");
1282 _fr = thread->last_frame();
1283 _is_done = false;
1284 }