1 /*
2 * Copyright (c) 1998, 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 "precompiled.hpp"
26 #include "code/codeBlob.hpp"
27 #include "code/codeCache.hpp"
28 #include "code/nmethod.hpp"
29 #include "code/scopeDesc.hpp"
30 #include "compiler/oopMap.hpp"
31 #include "gc_interface/collectedHeap.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "runtime/frame.inline.hpp"
35 #include "runtime/signature.hpp"
36 #ifdef COMPILER1
37 #include "c1/c1_Defs.hpp"
38 #endif
39
40 // OopMapStream
41
42 OopMapStream::OopMapStream(OopMap* oop_map) {
43 if(oop_map->omv_data() == NULL) {
44 _stream = new CompressedReadStream(oop_map->write_stream()->buffer());
45 } else {
46 _stream = new CompressedReadStream(oop_map->omv_data());
47 }
48 _mask = OopMapValue::type_mask_in_place;
49 _size = oop_map->omv_count();
50 _position = 0;
51 _valid_omv = false;
52 }
53
54
55 OopMapStream::OopMapStream(OopMap* oop_map, int oop_types_mask) {
56 if(oop_map->omv_data() == NULL) {
57 _stream = new CompressedReadStream(oop_map->write_stream()->buffer());
58 } else {
59 _stream = new CompressedReadStream(oop_map->omv_data());
60 }
61 _mask = oop_types_mask;
62 _size = oop_map->omv_count();
63 _position = 0;
64 _valid_omv = false;
65 }
66
67
68 void OopMapStream::find_next() {
69 while(_position++ < _size) {
70 _omv.read_from(_stream);
71 if(((int)_omv.type() & _mask) > 0) {
72 _valid_omv = true;
73 return;
74 }
75 }
76 _valid_omv = false;
77 }
78
79
80 // OopMap
81
82 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
83 // slots to hold 4-byte values like ints and floats in the LP64 build.
84 OopMap::OopMap(int frame_size, int arg_count) {
85 // OopMaps are usually quite so small, so pick a small initial size
86 set_write_stream(new CompressedWriteStream(32));
87 set_omv_data(NULL);
88 set_omv_count(0);
89
90 #ifdef ASSERT
91 _locs_length = VMRegImpl::stack2reg(0)->value() + frame_size + arg_count;
92 _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
93 for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
94 #endif
95 }
96
97
98 OopMap::OopMap(OopMap::DeepCopyToken, OopMap* source) {
99 // This constructor does a deep copy
100 // of the source OopMap.
101 set_write_stream(new CompressedWriteStream(source->omv_count() * 2));
102 set_omv_data(NULL);
103 set_omv_count(0);
104 set_offset(source->offset());
105
106 #ifdef ASSERT
107 _locs_length = source->_locs_length;
108 _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
109 for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
110 #endif
111
112 // We need to copy the entries too.
113 for (OopMapStream oms(source); !oms.is_done(); oms.next()) {
114 OopMapValue omv = oms.current();
115 omv.write_on(write_stream());
116 increment_count();
117 }
118 }
119
120
121 OopMap* OopMap::deep_copy() {
122 return new OopMap(_deep_copy_token, this);
123 }
124
125
126 void OopMap::copy_to(address addr) {
127 memcpy(addr,this,sizeof(OopMap));
128 memcpy(addr + sizeof(OopMap),write_stream()->buffer(),write_stream()->position());
129 OopMap* new_oop = (OopMap*)addr;
130 new_oop->set_omv_data_size(write_stream()->position());
131 new_oop->set_omv_data((unsigned char *)(addr + sizeof(OopMap)));
132 new_oop->set_write_stream(NULL);
133 }
134
135
136 int OopMap::heap_size() const {
137 int size = sizeof(OopMap);
138 int align = sizeof(void *) - 1;
139 if(write_stream() != NULL) {
140 size += write_stream()->position();
141 } else {
142 size += omv_data_size();
143 }
144 // Align to a reasonable ending point
145 size = ((size+align) & ~align);
146 return size;
147 }
148
149 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
150 // slots to hold 4-byte values like ints and floats in the LP64 build.
151 void OopMap::set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional) {
152
153 assert(reg->value() < _locs_length, "too big reg value for stack size");
154 assert( _locs_used[reg->value()] == OopMapValue::unused_value, "cannot insert twice" );
155 debug_only( _locs_used[reg->value()] = x; )
156
157 OopMapValue o(reg, x);
158
159 if(x == OopMapValue::callee_saved_value) {
160 // This can never be a stack location, so we don't need to transform it.
161 assert(optional->is_reg(), "Trying to callee save a stack location");
162 o.set_content_reg(optional);
163 } else if(x == OopMapValue::derived_oop_value) {
164 o.set_content_reg(optional);
165 }
166
167 o.write_on(write_stream());
168 increment_count();
169 }
170
171
172 void OopMap::set_oop(VMReg reg) {
173 set_xxx(reg, OopMapValue::oop_value, VMRegImpl::Bad());
174 }
175
176
177 void OopMap::set_value(VMReg reg) {
178 // At this time, we only need value entries in our OopMap when ZapDeadCompiledLocals is active.
179 if (ZapDeadCompiledLocals)
180 set_xxx(reg, OopMapValue::value_value, VMRegImpl::Bad());
181 }
182
183
184 void OopMap::set_narrowoop(VMReg reg) {
185 set_xxx(reg, OopMapValue::narrowoop_value, VMRegImpl::Bad());
186 }
187
188
189 void OopMap::set_callee_saved(VMReg reg, VMReg caller_machine_register ) {
190 set_xxx(reg, OopMapValue::callee_saved_value, caller_machine_register);
191 }
192
193
194 void OopMap::set_derived_oop(VMReg reg, VMReg derived_from_local_register ) {
195 if( reg == derived_from_local_register ) {
196 // Actually an oop, derived shares storage with base,
197 set_oop(reg);
198 } else {
199 set_xxx(reg, OopMapValue::derived_oop_value, derived_from_local_register);
200 }
201 }
202
203 // OopMapSet
204
205 OopMapSet::OopMapSet() {
206 set_om_size(MinOopMapAllocation);
207 set_om_count(0);
208 OopMap** temp = NEW_RESOURCE_ARRAY(OopMap*, om_size());
209 set_om_data(temp);
210 }
211
212
213 void OopMapSet::grow_om_data() {
214 int new_size = om_size() * 2;
215 OopMap** new_data = NEW_RESOURCE_ARRAY(OopMap*, new_size);
216 memcpy(new_data,om_data(),om_size() * sizeof(OopMap*));
217 set_om_size(new_size);
218 set_om_data(new_data);
219 }
220
221
222 void OopMapSet::copy_to(address addr) {
223 address temp = addr;
224 int align = sizeof(void *) - 1;
225 // Copy this
226 memcpy(addr,this,sizeof(OopMapSet));
227 temp += sizeof(OopMapSet);
228 temp = (address)((intptr_t)(temp + align) & ~align);
229 // Do the needed fixups to the new OopMapSet
230 OopMapSet* new_set = (OopMapSet*)addr;
231 new_set->set_om_data((OopMap**)temp);
232 // Allow enough space for the OopMap pointers
233 temp += (om_count() * sizeof(OopMap*));
234
235 for(int i=0; i < om_count(); i++) {
236 OopMap* map = at(i);
237 map->copy_to((address)temp);
238 new_set->set(i,(OopMap*)temp);
239 temp += map->heap_size();
240 }
241 // This "locks" the OopMapSet
242 new_set->set_om_size(-1);
243 }
244
245
246 void OopMapSet::add_gc_map(int pc_offset, OopMap *map ) {
247 assert(om_size() != -1,"Cannot grow a fixed OopMapSet");
248
249 if(om_count() >= om_size()) {
250 grow_om_data();
251 }
252 map->set_offset(pc_offset);
253
254 #ifdef ASSERT
255 if(om_count() > 0) {
256 OopMap* last = at(om_count()-1);
257 if (last->offset() == map->offset() ) {
258 fatal("OopMap inserted twice");
259 }
260 if(last->offset() > map->offset()) {
261 tty->print_cr( "WARNING, maps not sorted: pc[%d]=%d, pc[%d]=%d",
262 om_count(),last->offset(),om_count()+1,map->offset());
263 }
264 }
265 #endif // ASSERT
266
267 set(om_count(),map);
268 increment_count();
269 }
270
271
272 int OopMapSet::heap_size() const {
273 // The space we use
274 int size = sizeof(OopMap);
275 int align = sizeof(void *) - 1;
276 size = ((size+align) & ~align);
277 size += om_count() * sizeof(OopMap*);
278
279 // Now add in the space needed for the indivdiual OopMaps
280 for(int i=0; i < om_count(); i++) {
281 size += at(i)->heap_size();
282 }
283 // We don't need to align this, it will be naturally pointer aligned
284 return size;
285 }
286
287
288 OopMap* OopMapSet::singular_oop_map() {
289 guarantee(om_count() == 1, "Make sure we only have a single gc point");
290 return at(0);
291 }
292
293
294 OopMap* OopMapSet::find_map_at_offset(int pc_offset) const {
295 int i, len = om_count();
296 assert( len > 0, "must have pointer maps" );
297
298 // Scan through oopmaps. Stop when current offset is either equal or greater
299 // than the one we are looking for.
300 for( i = 0; i < len; i++) {
301 if( at(i)->offset() >= pc_offset )
302 break;
303 }
304
305 assert( i < len, "oopmap not found" );
306
307 OopMap* m = at(i);
308 assert( m->offset() == pc_offset, "oopmap not found" );
309 return m;
310 }
311
312 class DoNothingClosure: public OopClosure {
313 public:
314 void do_oop(oop* p) {}
315 void do_oop(narrowOop* p) {}
316 };
317 static DoNothingClosure do_nothing;
318
319 static void add_derived_oop(oop* base, oop* derived) {
320 #ifndef TIERED
321 COMPILER1_PRESENT(ShouldNotReachHere();)
322 #endif // TIERED
323 #ifdef COMPILER2
324 DerivedPointerTable::add(derived, base);
325 #endif // COMPILER2
326 }
327
328
329 #ifndef PRODUCT
330 static void trace_codeblob_maps(const frame *fr, const RegisterMap *reg_map) {
331 // Print oopmap and regmap
332 tty->print_cr("------ ");
333 CodeBlob* cb = fr->cb();
334 OopMapSet* maps = cb->oop_maps();
335 OopMap* map = cb->oop_map_for_return_address(fr->pc());
336 map->print();
337 if( cb->is_nmethod() ) {
338 nmethod* nm = (nmethod*)cb;
339 // native wrappers have no scope data, it is implied
340 if (nm->is_native_method()) {
341 tty->print("bci: 0 (native)");
342 } else {
343 ScopeDesc* scope = nm->scope_desc_at(fr->pc());
344 tty->print("bci: %d ",scope->bci());
345 }
346 }
347 tty->cr();
348 fr->print_on(tty);
349 tty->print(" ");
350 cb->print_value_on(tty); tty->cr();
351 reg_map->print();
352 tty->print_cr("------ ");
353
354 }
355 #endif // PRODUCT
356
357 void OopMapSet::oops_do(const frame *fr, const RegisterMap* reg_map, OopClosure* f) {
358 // add derived oops to a table
359 all_do(fr, reg_map, f, add_derived_oop, &do_nothing);
360 }
361
362
363 void OopMapSet::all_do(const frame *fr, const RegisterMap *reg_map,
364 OopClosure* oop_fn, void derived_oop_fn(oop*, oop*),
365 OopClosure* value_fn) {
366 CodeBlob* cb = fr->cb();
367 assert(cb != NULL, "no codeblob");
368
369 NOT_PRODUCT(if (TraceCodeBlobStacks) trace_codeblob_maps(fr, reg_map);)
370
371 OopMapSet* maps = cb->oop_maps();
372 OopMap* map = cb->oop_map_for_return_address(fr->pc());
373 assert(map != NULL, "no ptr map found");
374
375 // handle derived pointers first (otherwise base pointer may be
376 // changed before derived pointer offset has been collected)
377 OopMapValue omv;
378 {
379 OopMapStream oms(map,OopMapValue::derived_oop_value);
380 if (!oms.is_done()) {
381 #ifndef TIERED
382 COMPILER1_PRESENT(ShouldNotReachHere();)
383 #endif // !TIERED
384 // Protect the operation on the derived pointers. This
385 // protects the addition of derived pointers to the shared
386 // derived pointer table in DerivedPointerTable::add().
387 MutexLockerEx x(DerivedPointerTableGC_lock, Mutex::_no_safepoint_check_flag);
388 do {
389 omv = oms.current();
390 oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
391 if ( loc != NULL ) {
392 oop *base_loc = fr->oopmapreg_to_location(omv.content_reg(), reg_map);
393 oop *derived_loc = loc;
394 oop val = *base_loc;
395 if (val == (oop)NULL || Universe::is_narrow_oop_base(val)) {
396 // Ignore NULL oops and decoded NULL narrow oops which
397 // equal to Universe::narrow_oop_base when a narrow oop
398 // implicit null check is used in compiled code.
399 // The narrow_oop_base could be NULL or be the address
400 // of the page below heap depending on compressed oops mode.
401 } else
402 derived_oop_fn(base_loc, derived_loc);
403 }
404 oms.next();
405 } while (!oms.is_done());
406 }
407 }
408
409 // We want coop, value and oop oop_types
410 int mask = OopMapValue::oop_value | OopMapValue::value_value | OopMapValue::narrowoop_value;
411 {
412 for (OopMapStream oms(map,mask); !oms.is_done(); oms.next()) {
413 omv = oms.current();
414 oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
415 if ( loc != NULL ) {
416 if ( omv.type() == OopMapValue::oop_value ) {
417 oop val = *loc;
418 if (val == (oop)NULL || Universe::is_narrow_oop_base(val)) {
419 // Ignore NULL oops and decoded NULL narrow oops which
420 // equal to Universe::narrow_oop_base when a narrow oop
421 // implicit null check is used in compiled code.
422 // The narrow_oop_base could be NULL or be the address
423 // of the page below heap depending on compressed oops mode.
424 continue;
425 }
426 #ifdef ASSERT
427 if ((((uintptr_t)loc & (sizeof(*loc)-1)) != 0) ||
428 !Universe::heap()->is_in_or_null(*loc)) {
429 tty->print_cr("# Found non oop pointer. Dumping state at failure");
430 // try to dump out some helpful debugging information
431 trace_codeblob_maps(fr, reg_map);
432 omv.print();
433 tty->print_cr("register r");
434 omv.reg()->print();
435 tty->print_cr("loc = %p *loc = %p\n", loc, (address)*loc);
436 // do the real assert.
437 assert(Universe::heap()->is_in_or_null(*loc), "found non oop pointer");
438 }
439 #endif // ASSERT
440 oop_fn->do_oop(loc);
441 } else if ( omv.type() == OopMapValue::value_value ) {
442 assert((*loc) == (oop)NULL || !Universe::is_narrow_oop_base(*loc),
443 "found invalid value pointer");
444 value_fn->do_oop(loc);
445 } else if ( omv.type() == OopMapValue::narrowoop_value ) {
446 narrowOop *nl = (narrowOop*)loc;
447 #ifndef VM_LITTLE_ENDIAN
448 if (!omv.reg()->is_stack()) {
449 // compressed oops in registers only take up 4 bytes of an
450 // 8 byte register but they are in the wrong part of the
451 // word so adjust loc to point at the right place.
452 nl = (narrowOop*)((address)nl + 4);
453 }
454 #endif
455 oop_fn->do_oop(nl);
456 }
457 }
458 }
459 }
460 }
461
462
463 // Update callee-saved register info for the following frame
464 void OopMapSet::update_register_map(const frame *fr, RegisterMap *reg_map) {
465 ResourceMark rm;
466 CodeBlob* cb = fr->cb();
467 assert(cb != NULL, "no codeblob");
468
469 // Any reg might be saved by a safepoint handler (see generate_handler_blob).
470 const int max_saved_on_entry_reg_count = ConcreteRegisterImpl::number_of_registers;
471 assert( reg_map->_update_for_id == NULL || fr->is_older(reg_map->_update_for_id),
472 "already updated this map; do not 'update' it twice!" );
473 debug_only(reg_map->_update_for_id = fr->id());
474
475 // Check if caller must update oop argument
476 assert((reg_map->include_argument_oops() ||
477 !cb->caller_must_gc_arguments(reg_map->thread())),
478 "include_argument_oops should already be set");
479
480 int nof_callee = 0;
481 oop* locs[2*max_saved_on_entry_reg_count+1];
482 VMReg regs[2*max_saved_on_entry_reg_count+1];
483 // ("+1" because max_saved_on_entry_reg_count might be zero)
484
485 // Scan through oopmap and find location of all callee-saved registers
486 // (we do not do update in place, since info could be overwritten)
487
488 address pc = fr->pc();
489
490 OopMap* map = cb->oop_map_for_return_address(pc);
491
492 assert(map != NULL, " no ptr map found");
493
494 OopMapValue omv;
495 for(OopMapStream oms(map,OopMapValue::callee_saved_value); !oms.is_done(); oms.next()) {
496 omv = oms.current();
497 assert(nof_callee < 2*max_saved_on_entry_reg_count, "overflow");
498 regs[nof_callee] = omv.content_reg();
499 locs[nof_callee] = fr->oopmapreg_to_location(omv.reg(),reg_map);
500 nof_callee++;
501 }
502
503 // Check that runtime stubs save all callee-saved registers
504 #ifdef COMPILER2
505 assert(cb->is_compiled_by_c1() || !cb->is_runtime_stub() ||
506 (nof_callee >= SAVED_ON_ENTRY_REG_COUNT || nof_callee >= C_SAVED_ON_ENTRY_REG_COUNT),
507 "must save all");
508 #endif // COMPILER2
509
510 // Copy found callee-saved register to reg_map
511 for(int i = 0; i < nof_callee; i++) {
512 reg_map->set_location(regs[i], (address)locs[i]);
513 }
514 }
515
516 //=============================================================================
517 // Non-Product code
518
519 #ifndef PRODUCT
520
521 bool OopMap::has_derived_pointer() const {
522 #ifndef TIERED
523 COMPILER1_PRESENT(return false);
524 #endif // !TIERED
525 #ifdef COMPILER2
526 OopMapStream oms((OopMap*)this,OopMapValue::derived_oop_value);
527 return oms.is_done();
528 #else
529 return false;
530 #endif // COMPILER2
531 }
532
533 #endif //PRODUCT
534
535 // Printing code is present in product build for -XX:+PrintAssembly.
536
537 static
538 void print_register_type(OopMapValue::oop_types x, VMReg optional,
539 outputStream* st) {
540 switch( x ) {
541 case OopMapValue::oop_value:
542 st->print("Oop");
543 break;
544 case OopMapValue::value_value:
545 st->print("Value" );
546 break;
547 case OopMapValue::narrowoop_value:
548 tty->print("NarrowOop" );
549 break;
550 case OopMapValue::callee_saved_value:
551 st->print("Callers_" );
552 optional->print_on(st);
553 break;
554 case OopMapValue::derived_oop_value:
555 st->print("Derived_oop_" );
556 optional->print_on(st);
557 break;
558 default:
559 ShouldNotReachHere();
560 }
561 }
562
563
564 void OopMapValue::print_on(outputStream* st) const {
565 reg()->print_on(st);
566 st->print("=");
567 print_register_type(type(),content_reg(),st);
568 st->print(" ");
569 }
570
571
572 void OopMap::print_on(outputStream* st) const {
573 OopMapValue omv;
574 st->print("OopMap{");
575 for(OopMapStream oms((OopMap*)this); !oms.is_done(); oms.next()) {
576 omv = oms.current();
577 omv.print_on(st);
578 }
579 st->print("off=%d}", (int) offset());
580 }
581
582
583 void OopMapSet::print_on(outputStream* st) const {
584 int i, len = om_count();
585
586 st->print_cr("OopMapSet contains %d OopMaps\n",len);
587
588 for( i = 0; i < len; i++) {
589 OopMap* m = at(i);
590 st->print_cr("#%d ",i);
591 m->print_on(st);
592 st->cr();
593 }
594 }
595
596
597
598 //------------------------------DerivedPointerTable---------------------------
599
600 #ifdef COMPILER2
601
602 class DerivedPointerEntry : public CHeapObj {
603 private:
604 oop* _location; // Location of derived pointer (also pointing to the base)
605 intptr_t _offset; // Offset from base pointer
606 public:
607 DerivedPointerEntry(oop* location, intptr_t offset) { _location = location; _offset = offset; }
608 oop* location() { return _location; }
609 intptr_t offset() { return _offset; }
610 };
611
612
613 GrowableArray<DerivedPointerEntry*>* DerivedPointerTable::_list = NULL;
614 bool DerivedPointerTable::_active = false;
615
616
617 void DerivedPointerTable::clear() {
618 // The first time, we create the list. Otherwise it should be
619 // empty. If not, then we have probably forgotton to call
620 // update_pointers after last GC/Scavenge.
621 assert (!_active, "should not be active");
622 assert(_list == NULL || _list->length() == 0, "table not empty");
623 if (_list == NULL) {
624 _list = new (ResourceObj::C_HEAP) GrowableArray<DerivedPointerEntry*>(10, true); // Allocated on C heap
625 }
626 _active = true;
627 }
628
629
630 // Returns value of location as an int
631 intptr_t value_of_loc(oop *pointer) { return (intptr_t)(*pointer); }
632
633
634 void DerivedPointerTable::add(oop *derived_loc, oop *base_loc) {
635 assert(Universe::heap()->is_in_or_null(*base_loc), "not an oop");
636 assert(derived_loc != base_loc, "Base and derived in same location");
637 if (_active) {
638 assert(*derived_loc != (oop)base_loc, "location already added");
639 assert(_list != NULL, "list must exist");
640 intptr_t offset = value_of_loc(derived_loc) - value_of_loc(base_loc);
641 // This assert is invalid because derived pointers can be
642 // arbitrarily far away from their base.
643 // assert(offset >= -1000000, "wrong derived pointer info");
644
645 if (TraceDerivedPointers) {
646 tty->print_cr(
647 "Add derived pointer@" INTPTR_FORMAT
648 " - Derived: " INTPTR_FORMAT
649 " Base: " INTPTR_FORMAT " (@" INTPTR_FORMAT ") (Offset: %d)",
650 derived_loc, (address)*derived_loc, (address)*base_loc, base_loc, offset
651 );
652 }
653 // Set derived oop location to point to base.
654 *derived_loc = (oop)base_loc;
655 assert_lock_strong(DerivedPointerTableGC_lock);
656 DerivedPointerEntry *entry = new DerivedPointerEntry(derived_loc, offset);
657 _list->append(entry);
658 }
659 }
660
661
662 void DerivedPointerTable::update_pointers() {
663 assert(_list != NULL, "list must exist");
664 for(int i = 0; i < _list->length(); i++) {
665 DerivedPointerEntry* entry = _list->at(i);
666 oop* derived_loc = entry->location();
667 intptr_t offset = entry->offset();
668 // The derived oop was setup to point to location of base
669 oop base = **(oop**)derived_loc;
670 assert(Universe::heap()->is_in_or_null(base), "must be an oop");
671
672 *derived_loc = (oop)(((address)base) + offset);
673 assert(value_of_loc(derived_loc) - value_of_loc(&base) == offset, "sanity check");
674
675 if (TraceDerivedPointers) {
676 tty->print_cr("Updating derived pointer@" INTPTR_FORMAT
677 " - Derived: " INTPTR_FORMAT " Base: " INTPTR_FORMAT " (Offset: %d)",
678 derived_loc, (address)*derived_loc, (address)base, offset);
679 }
680
681 // Delete entry
682 delete entry;
683 _list->at_put(i, NULL);
684 }
685 // Clear list, so it is ready for next traversal (this is an invariant)
686 if (TraceDerivedPointers && !_list->is_empty()) {
687 tty->print_cr("--------------------------");
688 }
689 _list->clear();
690 _active = false;
691 }
692
693 #endif // COMPILER2