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 assert(offset >= -1000000, "wrong derived pointer info"); 642 643 if (TraceDerivedPointers) { 644 tty->print_cr( 645 "Add derived pointer@" INTPTR_FORMAT 646 " - Derived: " INTPTR_FORMAT 647 " Base: " INTPTR_FORMAT " (@" INTPTR_FORMAT ") (Offset: %d)", 648 derived_loc, (address)*derived_loc, (address)*base_loc, base_loc, offset 649 ); 650 } 651 // Set derived oop location to point to base. 652 *derived_loc = (oop)base_loc; 653 assert_lock_strong(DerivedPointerTableGC_lock); 654 DerivedPointerEntry *entry = new DerivedPointerEntry(derived_loc, offset); 655 _list->append(entry); 656 } 657 } 658 659 660 void DerivedPointerTable::update_pointers() { 661 assert(_list != NULL, "list must exist"); 662 for(int i = 0; i < _list->length(); i++) { 663 DerivedPointerEntry* entry = _list->at(i); 664 oop* derived_loc = entry->location(); 665 intptr_t offset = entry->offset(); 666 // The derived oop was setup to point to location of base 667 oop base = **(oop**)derived_loc; 668 assert(Universe::heap()->is_in_or_null(base), "must be an oop"); 669 670 *derived_loc = (oop)(((address)base) + offset); 671 assert(value_of_loc(derived_loc) - value_of_loc(&base) == offset, "sanity check"); 672 673 if (TraceDerivedPointers) { 674 tty->print_cr("Updating derived pointer@" INTPTR_FORMAT 675 " - Derived: " INTPTR_FORMAT " Base: " INTPTR_FORMAT " (Offset: %d)", 676 derived_loc, (address)*derived_loc, (address)base, offset); 677 } 678 679 // Delete entry 680 delete entry; 681 _list->at_put(i, NULL); 682 } 683 // Clear list, so it is ready for next traversal (this is an invariant) 684 if (TraceDerivedPointers && !_list->is_empty()) { 685 tty->print_cr("--------------------------"); 686 } 687 _list->clear(); 688 _active = false; 689 } 690 691 #endif // COMPILER2