1 /*
   2  * Copyright (c) 1998, 2019, 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/shared/collectedHeap.hpp"
  32 #include "memory/allocation.inline.hpp"
  33 #include "memory/iterator.hpp"
  34 #include "memory/resourceArea.hpp"
  35 #include "memory/universe.hpp"
  36 #include "oops/compressedOops.hpp"
  37 #include "runtime/frame.inline.hpp"
  38 #include "runtime/handles.inline.hpp"
  39 #include "runtime/signature.hpp"
  40 #include "utilities/align.hpp"
  41 #include "utilities/lockFreeStack.hpp"
  42 #ifdef COMPILER1
  43 #include "c1/c1_Defs.hpp"
  44 #endif
  45 #ifdef COMPILER2
  46 #include "opto/optoreg.hpp"
  47 #endif
  48 
  49 // OopMapStream
  50 
  51 OopMapStream::OopMapStream(OopMap* oop_map, int oop_types_mask) {
  52   _stream = new CompressedReadStream(oop_map->write_stream()->buffer());
  53   _mask = oop_types_mask;
  54   _size = oop_map->omv_count();
  55   _position = 0;
  56   _valid_omv = false;
  57 }
  58 
  59 OopMapStream::OopMapStream(const ImmutableOopMap* oop_map, int oop_types_mask) {
  60   _stream = new CompressedReadStream(oop_map->data_addr());
  61   _mask = oop_types_mask;
  62   _size = oop_map->count();
  63   _position = 0;
  64   _valid_omv = false;
  65 }
  66 
  67 void OopMapStream::find_next() {
  68   while(_position++ < _size) {
  69     _omv.read_from(_stream);
  70     if(((int)_omv.type() & _mask) > 0) {
  71       _valid_omv = true;
  72       return;
  73     }
  74   }
  75   _valid_omv = false;
  76 }
  77 
  78 
  79 // OopMap
  80 
  81 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
  82 // slots to hold 4-byte values like ints and floats in the LP64 build.
  83 OopMap::OopMap(int frame_size, int arg_count) {
  84   // OopMaps are usually quite so small, so pick a small initial size
  85   set_write_stream(new CompressedWriteStream(32));
  86   set_omv_count(0);
  87 
  88 #ifdef ASSERT
  89   _locs_length = VMRegImpl::stack2reg(0)->value() + frame_size + arg_count;
  90   _locs_used   = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
  91   for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
  92 #endif
  93 }
  94 
  95 
  96 OopMap::OopMap(OopMap::DeepCopyToken, OopMap* source) {
  97   // This constructor does a deep copy
  98   // of the source OopMap.
  99   set_write_stream(new CompressedWriteStream(source->omv_count() * 2));
 100   set_omv_count(0);
 101   set_offset(source->offset());
 102 
 103 #ifdef ASSERT
 104   _locs_length = source->_locs_length;
 105   _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
 106   for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
 107 #endif
 108 
 109   // We need to copy the entries too.
 110   for (OopMapStream oms(source); !oms.is_done(); oms.next()) {
 111     OopMapValue omv = oms.current();
 112     omv.write_on(write_stream());
 113     increment_count();
 114   }
 115 }
 116 
 117 
 118 OopMap* OopMap::deep_copy() {
 119   return new OopMap(_deep_copy_token, this);
 120 }
 121 
 122 void OopMap::copy_data_to(address addr) const {
 123   memcpy(addr, write_stream()->buffer(), write_stream()->position());
 124 }
 125 
 126 int OopMap::heap_size() const {
 127   int size = sizeof(OopMap);
 128   int align = sizeof(void *) - 1;
 129   size += write_stream()->position();
 130   // Align to a reasonable ending point
 131   size = ((size+align) & ~align);
 132   return size;
 133 }
 134 
 135 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
 136 // slots to hold 4-byte values like ints and floats in the LP64 build.
 137 void OopMap::set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional) {
 138 
 139   assert(reg->value() < _locs_length, "too big reg value for stack size");
 140   assert( _locs_used[reg->value()] == OopMapValue::unused_value, "cannot insert twice" );
 141   debug_only( _locs_used[reg->value()] = x; )
 142 
 143   OopMapValue o(reg, x);
 144 
 145   if(x == OopMapValue::callee_saved_value) {
 146     // This can never be a stack location, so we don't need to transform it.
 147     assert(optional->is_reg(), "Trying to callee save a stack location");
 148     o.set_content_reg(optional);
 149   } else if(x == OopMapValue::derived_oop_value) {
 150     o.set_content_reg(optional);
 151   }
 152 
 153   o.write_on(write_stream());
 154   increment_count();
 155 }
 156 
 157 
 158 void OopMap::set_oop(VMReg reg) {
 159   set_xxx(reg, OopMapValue::oop_value, VMRegImpl::Bad());
 160 }
 161 
 162 
 163 void OopMap::set_value(VMReg reg) {
 164   // At this time, we don't need value entries in our OopMap.
 165 }
 166 
 167 
 168 void OopMap::set_narrowoop(VMReg reg) {
 169   set_xxx(reg, OopMapValue::narrowoop_value, VMRegImpl::Bad());
 170 }
 171 
 172 
 173 void OopMap::set_callee_saved(VMReg reg, VMReg caller_machine_register ) {
 174   set_xxx(reg, OopMapValue::callee_saved_value, caller_machine_register);
 175 }
 176 
 177 
 178 void OopMap::set_derived_oop(VMReg reg, VMReg derived_from_local_register ) {
 179   if( reg == derived_from_local_register ) {
 180     // Actually an oop, derived shares storage with base,
 181     set_oop(reg);
 182   } else {
 183     set_xxx(reg, OopMapValue::derived_oop_value, derived_from_local_register);
 184   }
 185 }
 186 
 187 // OopMapSet
 188 
 189 OopMapSet::OopMapSet() {
 190   set_om_size(MinOopMapAllocation);
 191   set_om_count(0);
 192   OopMap** temp = NEW_RESOURCE_ARRAY(OopMap*, om_size());
 193   set_om_data(temp);
 194 }
 195 
 196 
 197 void OopMapSet::grow_om_data() {
 198   int new_size = om_size() * 2;
 199   OopMap** new_data = NEW_RESOURCE_ARRAY(OopMap*, new_size);
 200   memcpy(new_data,om_data(),om_size() * sizeof(OopMap*));
 201   set_om_size(new_size);
 202   set_om_data(new_data);
 203 }
 204 
 205 void OopMapSet::add_gc_map(int pc_offset, OopMap *map ) {
 206   assert(om_size() != -1,"Cannot grow a fixed OopMapSet");
 207 
 208   if(om_count() >= om_size()) {
 209     grow_om_data();
 210   }
 211   map->set_offset(pc_offset);
 212 
 213 #ifdef ASSERT
 214   if(om_count() > 0) {
 215     OopMap* last = at(om_count()-1);
 216     if (last->offset() == map->offset() ) {
 217       fatal("OopMap inserted twice");
 218     }
 219     if(last->offset() > map->offset()) {
 220       tty->print_cr( "WARNING, maps not sorted: pc[%d]=%d, pc[%d]=%d",
 221                       om_count(),last->offset(),om_count()+1,map->offset());
 222     }
 223   }
 224 #endif // ASSERT
 225 
 226   set(om_count(),map);
 227   increment_count();
 228 }
 229 
 230 
 231 int OopMapSet::heap_size() const {
 232   // The space we use
 233   int size = sizeof(OopMap);
 234   int align = sizeof(void *) - 1;
 235   size = ((size+align) & ~align);
 236   size += om_count() * sizeof(OopMap*);
 237 
 238   // Now add in the space needed for the indivdiual OopMaps
 239   for(int i=0; i < om_count(); i++) {
 240     size += at(i)->heap_size();
 241   }
 242   // We don't need to align this, it will be naturally pointer aligned
 243   return size;
 244 }
 245 
 246 
 247 OopMap* OopMapSet::singular_oop_map() {
 248   guarantee(om_count() == 1, "Make sure we only have a single gc point");
 249   return at(0);
 250 }
 251 
 252 
 253 OopMap* OopMapSet::find_map_at_offset(int pc_offset) const {
 254   int i, len = om_count();
 255   assert( len > 0, "must have pointer maps" );
 256 
 257   // Scan through oopmaps. Stop when current offset is either equal or greater
 258   // than the one we are looking for.
 259   for( i = 0; i < len; i++) {
 260     if( at(i)->offset() >= pc_offset )
 261       break;
 262   }
 263 
 264   assert( i < len, "oopmap not found" );
 265 
 266   OopMap* m = at(i);
 267   assert( m->offset() == pc_offset, "oopmap not found" );
 268   return m;
 269 }
 270 
 271 static void add_derived_oop(oop* base, oop* derived) {
 272 #if !defined(TIERED) && !INCLUDE_JVMCI
 273   COMPILER1_PRESENT(ShouldNotReachHere();)
 274 #endif // !defined(TIERED) && !INCLUDE_JVMCI
 275 #if COMPILER2_OR_JVMCI
 276   DerivedPointerTable::add(derived, base);
 277 #endif // COMPILER2_OR_JVMCI
 278 }
 279 
 280 
 281 #ifndef PRODUCT
 282 static void trace_codeblob_maps(const frame *fr, const RegisterMap *reg_map) {
 283   // Print oopmap and regmap
 284   tty->print_cr("------ ");
 285   CodeBlob* cb = fr->cb();
 286   const ImmutableOopMapSet* maps = cb->oop_maps();
 287   const ImmutableOopMap* map = cb->oop_map_for_return_address(fr->pc());
 288   map->print();
 289   if( cb->is_nmethod() ) {
 290     nmethod* nm = (nmethod*)cb;
 291     // native wrappers have no scope data, it is implied
 292     if (nm->is_native_method()) {
 293       tty->print("bci: 0 (native)");
 294     } else {
 295       ScopeDesc* scope  = nm->scope_desc_at(fr->pc());
 296       tty->print("bci: %d ",scope->bci());
 297     }
 298   }
 299   tty->cr();
 300   fr->print_on(tty);
 301   tty->print("     ");
 302   cb->print_value_on(tty);  tty->cr();
 303   reg_map->print();
 304   tty->print_cr("------ ");
 305 
 306 }
 307 #endif // PRODUCT
 308 
 309 void OopMapSet::oops_do(const frame *fr, const RegisterMap* reg_map, OopClosure* f) {
 310   // add derived oops to a table
 311   all_do(fr, reg_map, f, add_derived_oop, &do_nothing_cl);
 312 }
 313 
 314 
 315 void OopMapSet::all_do(const frame *fr, const RegisterMap *reg_map,
 316                        OopClosure* oop_fn, void derived_oop_fn(oop*, oop*),
 317                        OopClosure* value_fn) {
 318   CodeBlob* cb = fr->cb();
 319   assert(cb != NULL, "no codeblob");
 320 
 321   NOT_PRODUCT(if (TraceCodeBlobStacks) trace_codeblob_maps(fr, reg_map);)
 322 
 323   const ImmutableOopMapSet* maps = cb->oop_maps();
 324   const ImmutableOopMap* map = cb->oop_map_for_return_address(fr->pc());
 325   assert(map != NULL, "no ptr map found");
 326 
 327   // handle derived pointers first (otherwise base pointer may be
 328   // changed before derived pointer offset has been collected)
 329   OopMapValue omv;
 330   {
 331     OopMapStream oms(map,OopMapValue::derived_oop_value);
 332     if (!oms.is_done()) {
 333 #ifndef TIERED
 334       COMPILER1_PRESENT(ShouldNotReachHere();)
 335 #if INCLUDE_JVMCI
 336       if (UseJVMCICompiler) {
 337         ShouldNotReachHere();
 338       }
 339 #endif
 340 #endif // !TIERED
 341       do {
 342         omv = oms.current();
 343         oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
 344         guarantee(loc != NULL, "missing saved register");
 345         oop *derived_loc = loc;
 346         oop *base_loc    = fr->oopmapreg_to_location(omv.content_reg(), reg_map);
 347         // Ignore NULL oops and decoded NULL narrow oops which
 348         // equal to CompressedOops::base() when a narrow oop
 349         // implicit null check is used in compiled code.
 350         // The narrow_oop_base could be NULL or be the address
 351         // of the page below heap depending on compressed oops mode.
 352         if (base_loc != NULL && *base_loc != NULL && !CompressedOops::is_base(*base_loc)) {
 353           derived_oop_fn(base_loc, derived_loc);
 354         }
 355         oms.next();
 356       }  while (!oms.is_done());
 357     }
 358   }
 359 
 360   // We want coop and oop oop_types
 361   int mask = OopMapValue::oop_value | OopMapValue::narrowoop_value;
 362   {
 363     for (OopMapStream oms(map,mask); !oms.is_done(); oms.next()) {
 364       omv = oms.current();
 365       oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
 366       // It should be an error if no location can be found for a
 367       // register mentioned as contained an oop of some kind.  Maybe
 368       // this was allowed previously because value_value items might
 369       // be missing?
 370       guarantee(loc != NULL, "missing saved register");
 371       if ( omv.type() == OopMapValue::oop_value ) {
 372         oop val = *loc;
 373         if (val == NULL || CompressedOops::is_base(val)) {
 374           // Ignore NULL oops and decoded NULL narrow oops which
 375           // equal to CompressedOops::base() when a narrow oop
 376           // implicit null check is used in compiled code.
 377           // The narrow_oop_base could be NULL or be the address
 378           // of the page below heap depending on compressed oops mode.
 379           continue;
 380         }
 381 #ifdef ASSERT
 382         if ((((uintptr_t)loc & (sizeof(*loc)-1)) != 0) ||
 383             !Universe::heap()->is_in_or_null(*loc)) {
 384           tty->print_cr("# Found non oop pointer.  Dumping state at failure");
 385           // try to dump out some helpful debugging information
 386           trace_codeblob_maps(fr, reg_map);
 387           omv.print();
 388           tty->print_cr("register r");
 389           omv.reg()->print();
 390           tty->print_cr("loc = %p *loc = %p\n", loc, (address)*loc);
 391           // do the real assert.
 392           assert(Universe::heap()->is_in_or_null(*loc), "found non oop pointer");
 393         }
 394 #endif // ASSERT
 395         oop_fn->do_oop(loc);
 396       } else if ( omv.type() == OopMapValue::narrowoop_value ) {
 397         narrowOop *nl = (narrowOop*)loc;
 398 #ifndef VM_LITTLE_ENDIAN
 399         VMReg vmReg = omv.reg();
 400         // Don't do this on SPARC float registers as they can be individually addressed
 401         if (!vmReg->is_stack() SPARC_ONLY(&& !vmReg->is_FloatRegister())) {
 402           // compressed oops in registers only take up 4 bytes of an
 403           // 8 byte register but they are in the wrong part of the
 404           // word so adjust loc to point at the right place.
 405           nl = (narrowOop*)((address)nl + 4);
 406         }
 407 #endif
 408         oop_fn->do_oop(nl);
 409       }
 410     }
 411   }
 412 }
 413 
 414 
 415 // Update callee-saved register info for the following frame
 416 void OopMapSet::update_register_map(const frame *fr, RegisterMap *reg_map) {
 417   ResourceMark rm;
 418   CodeBlob* cb = fr->cb();
 419   assert(cb != NULL, "no codeblob");
 420 
 421   // Any reg might be saved by a safepoint handler (see generate_handler_blob).
 422   assert( reg_map->_update_for_id == NULL || fr->is_older(reg_map->_update_for_id),
 423          "already updated this map; do not 'update' it twice!" );
 424   debug_only(reg_map->_update_for_id = fr->id());
 425 
 426   // Check if caller must update oop argument
 427   assert((reg_map->include_argument_oops() ||
 428           !cb->caller_must_gc_arguments(reg_map->thread())),
 429          "include_argument_oops should already be set");
 430 
 431   // Scan through oopmap and find location of all callee-saved registers
 432   // (we do not do update in place, since info could be overwritten)
 433 
 434   address pc = fr->pc();
 435   const ImmutableOopMap* map  = cb->oop_map_for_return_address(pc);
 436   assert(map != NULL, "no ptr map found");
 437   DEBUG_ONLY(int nof_callee = 0;)
 438 
 439   for (OopMapStream oms(map, OopMapValue::callee_saved_value); !oms.is_done(); oms.next()) {
 440     OopMapValue omv = oms.current();
 441     VMReg reg = omv.content_reg();
 442     oop* loc = fr->oopmapreg_to_location(omv.reg(), reg_map);
 443     reg_map->set_location(reg, (address) loc);
 444     DEBUG_ONLY(nof_callee++;)
 445   }
 446 
 447   // Check that runtime stubs save all callee-saved registers
 448 #ifdef COMPILER2
 449   assert(cb->is_compiled_by_c1() || cb->is_compiled_by_jvmci() || !cb->is_runtime_stub() ||
 450          (nof_callee >= SAVED_ON_ENTRY_REG_COUNT || nof_callee >= C_SAVED_ON_ENTRY_REG_COUNT),
 451          "must save all");
 452 #endif // COMPILER2
 453 }
 454 
 455 //=============================================================================
 456 // Non-Product code
 457 
 458 #ifndef PRODUCT
 459 
 460 bool ImmutableOopMap::has_derived_pointer() const {
 461 #if !defined(TIERED) && !INCLUDE_JVMCI
 462   COMPILER1_PRESENT(return false);
 463 #endif // !TIERED
 464 #if COMPILER2_OR_JVMCI
 465   OopMapStream oms(this,OopMapValue::derived_oop_value);
 466   return oms.is_done();
 467 #else
 468   return false;
 469 #endif // COMPILER2_OR_JVMCI
 470 }
 471 
 472 #endif //PRODUCT
 473 
 474 // Printing code is present in product build for -XX:+PrintAssembly.
 475 
 476 static
 477 void print_register_type(OopMapValue::oop_types x, VMReg optional,
 478                          outputStream* st) {
 479   switch( x ) {
 480   case OopMapValue::oop_value:
 481     st->print("Oop");
 482     break;
 483   case OopMapValue::narrowoop_value:
 484     st->print("NarrowOop");
 485     break;
 486   case OopMapValue::callee_saved_value:
 487     st->print("Callers_");
 488     optional->print_on(st);
 489     break;
 490   case OopMapValue::derived_oop_value:
 491     st->print("Derived_oop_");
 492     optional->print_on(st);
 493     break;
 494   default:
 495     ShouldNotReachHere();
 496   }
 497 }
 498 
 499 void OopMapValue::print_on(outputStream* st) const {
 500   reg()->print_on(st);
 501   st->print("=");
 502   print_register_type(type(),content_reg(),st);
 503   st->print(" ");
 504 }
 505 
 506 void OopMapValue::print() const { print_on(tty); }
 507 
 508 void ImmutableOopMap::print_on(outputStream* st) const {
 509   OopMapValue omv;
 510   st->print("ImmutableOopMap {");
 511   for(OopMapStream oms(this); !oms.is_done(); oms.next()) {
 512     omv = oms.current();
 513     omv.print_on(st);
 514   }
 515   st->print("}");
 516 }
 517 
 518 void ImmutableOopMap::print() const { print_on(tty); }
 519 
 520 void OopMap::print_on(outputStream* st) const {
 521   OopMapValue omv;
 522   st->print("OopMap {");
 523   for(OopMapStream oms((OopMap*)this); !oms.is_done(); oms.next()) {
 524     omv = oms.current();
 525     omv.print_on(st);
 526   }
 527   // Print hex offset in addition.
 528   st->print("off=%d/0x%x}", (int) offset(), (int) offset());
 529 }
 530 
 531 void OopMap::print() const { print_on(tty); }
 532 
 533 void ImmutableOopMapSet::print_on(outputStream* st) const {
 534   const ImmutableOopMap* last = NULL;
 535   const int len = count();
 536 
 537   st->print_cr("ImmutableOopMapSet contains %d OopMaps", len);
 538 
 539   for (int i = 0; i < len; i++) {
 540     const ImmutableOopMapPair* pair = pair_at(i);
 541     const ImmutableOopMap* map = pair->get_from(this);
 542     if (map != last) {
 543       st->cr();
 544       map->print_on(st);
 545       st->print(" pc offsets: ");
 546     }
 547     last = map;
 548     st->print("%d ", pair->pc_offset());
 549   }
 550   st->cr();
 551 }
 552 
 553 void ImmutableOopMapSet::print() const { print_on(tty); }
 554 
 555 void OopMapSet::print_on(outputStream* st) const {
 556   const int len = om_count();
 557 
 558   st->print_cr("OopMapSet contains %d OopMaps", len);
 559 
 560   for( int i = 0; i < len; i++) {
 561     OopMap* m = at(i);
 562     st->print_cr("#%d ",i);
 563     m->print_on(st);
 564     st->cr();
 565   }
 566   st->cr();
 567 }
 568 
 569 void OopMapSet::print() const { print_on(tty); }
 570 
 571 bool OopMap::equals(const OopMap* other) const {
 572   if (other->_omv_count != _omv_count) {
 573     return false;
 574   }
 575   if (other->write_stream()->position() != write_stream()->position()) {
 576     return false;
 577   }
 578   if (memcmp(other->write_stream()->buffer(), write_stream()->buffer(), write_stream()->position()) != 0) {
 579     return false;
 580   }
 581   return true;
 582 }
 583 
 584 const ImmutableOopMap* ImmutableOopMapSet::find_map_at_offset(int pc_offset) const {
 585   ImmutableOopMapPair* pairs = get_pairs();
 586   ImmutableOopMapPair* last  = NULL;
 587 
 588   for (int i = 0; i < _count; ++i) {
 589     if (pairs[i].pc_offset() >= pc_offset) {
 590       last = &pairs[i];
 591       break;
 592     }
 593   }
 594 
 595   // Heal Coverity issue: potential index out of bounds access.
 596   guarantee(last != NULL, "last may not be null");
 597   assert(last->pc_offset() == pc_offset, "oopmap not found");
 598   return last->get_from(this);
 599 }
 600 
 601 const ImmutableOopMap* ImmutableOopMapPair::get_from(const ImmutableOopMapSet* set) const {
 602   return set->oopmap_at_offset(_oopmap_offset);
 603 }
 604 
 605 ImmutableOopMap::ImmutableOopMap(const OopMap* oopmap) : _count(oopmap->count()) {
 606   address addr = data_addr();
 607   oopmap->copy_data_to(addr);
 608 }
 609 
 610 #ifdef ASSERT
 611 int ImmutableOopMap::nr_of_bytes() const {
 612   OopMapStream oms(this);
 613 
 614   while (!oms.is_done()) {
 615     oms.next();
 616   }
 617   return sizeof(ImmutableOopMap) + oms.stream_position();
 618 }
 619 #endif
 620 
 621 ImmutableOopMapBuilder::ImmutableOopMapBuilder(const OopMapSet* set) : _set(set), _empty(NULL), _last(NULL), _empty_offset(-1), _last_offset(-1), _offset(0), _required(-1), _new_set(NULL) {
 622   _mapping = NEW_RESOURCE_ARRAY(Mapping, _set->size());
 623 }
 624 
 625 int ImmutableOopMapBuilder::size_for(const OopMap* map) const {
 626   return align_up((int)sizeof(ImmutableOopMap) + map->data_size(), 8);
 627 }
 628 
 629 int ImmutableOopMapBuilder::heap_size() {
 630   int base = sizeof(ImmutableOopMapSet);
 631   base = align_up(base, 8);
 632 
 633   // all of ours pc / offset pairs
 634   int pairs = _set->size() * sizeof(ImmutableOopMapPair);
 635   pairs = align_up(pairs, 8);
 636 
 637   for (int i = 0; i < _set->size(); ++i) {
 638     int size = 0;
 639     OopMap* map = _set->at(i);
 640 
 641     if (is_empty(map)) {
 642       /* only keep a single empty map in the set */
 643       if (has_empty()) {
 644         _mapping[i].set(Mapping::OOPMAP_EMPTY, _empty_offset, 0, map, _empty);
 645       } else {
 646         _empty_offset = _offset;
 647         _empty = map;
 648         size = size_for(map);
 649         _mapping[i].set(Mapping::OOPMAP_NEW, _offset, size, map);
 650       }
 651     } else if (is_last_duplicate(map)) {
 652       /* if this entry is identical to the previous one, just point it there */
 653       _mapping[i].set(Mapping::OOPMAP_DUPLICATE, _last_offset, 0, map, _last);
 654     } else {
 655       /* not empty, not an identical copy of the previous entry */
 656       size = size_for(map);
 657       _mapping[i].set(Mapping::OOPMAP_NEW, _offset, size, map);
 658       _last_offset = _offset;
 659       _last = map;
 660     }
 661 
 662     assert(_mapping[i]._map == map, "check");
 663     _offset += size;
 664   }
 665 
 666   int total = base + pairs + _offset;
 667   DEBUG_ONLY(total += 8);
 668   _required = total;
 669   return total;
 670 }
 671 
 672 void ImmutableOopMapBuilder::fill_pair(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set) {
 673   assert(offset < set->nr_of_bytes(), "check");
 674   new ((address) pair) ImmutableOopMapPair(map->offset(), offset);
 675 }
 676 
 677 int ImmutableOopMapBuilder::fill_map(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set) {
 678   fill_pair(pair, map, offset, set);
 679   address addr = (address) pair->get_from(_new_set); // location of the ImmutableOopMap
 680 
 681   new (addr) ImmutableOopMap(map);
 682   return size_for(map);
 683 }
 684 
 685 void ImmutableOopMapBuilder::fill(ImmutableOopMapSet* set, int sz) {
 686   ImmutableOopMapPair* pairs = set->get_pairs();
 687 
 688   for (int i = 0; i < set->count(); ++i) {
 689     const OopMap* map = _mapping[i]._map;
 690     ImmutableOopMapPair* pair = NULL;
 691     int size = 0;
 692 
 693     if (_mapping[i]._kind == Mapping::OOPMAP_NEW) {
 694       size = fill_map(&pairs[i], map, _mapping[i]._offset, set);
 695     } else if (_mapping[i]._kind == Mapping::OOPMAP_DUPLICATE || _mapping[i]._kind == Mapping::OOPMAP_EMPTY) {
 696       fill_pair(&pairs[i], map, _mapping[i]._offset, set);
 697     }
 698 
 699     const ImmutableOopMap* nv = set->find_map_at_offset(map->offset());
 700     assert(memcmp(map->data(), nv->data_addr(), map->data_size()) == 0, "check identity");
 701   }
 702 }
 703 
 704 #ifdef ASSERT
 705 void ImmutableOopMapBuilder::verify(address buffer, int size, const ImmutableOopMapSet* set) {
 706   for (int i = 0; i < 8; ++i) {
 707     assert(buffer[size - 8 + i] == (unsigned char) 0xff, "overwritten memory check");
 708   }
 709 
 710   for (int i = 0; i < set->count(); ++i) {
 711     const ImmutableOopMapPair* pair = set->pair_at(i);
 712     assert(pair->oopmap_offset() < set->nr_of_bytes(), "check size");
 713     const ImmutableOopMap* map = pair->get_from(set);
 714     int nr_of_bytes = map->nr_of_bytes();
 715     assert(pair->oopmap_offset() + nr_of_bytes <= set->nr_of_bytes(), "check size + size");
 716   }
 717 }
 718 #endif
 719 
 720 ImmutableOopMapSet* ImmutableOopMapBuilder::generate_into(address buffer) {
 721   DEBUG_ONLY(memset(&buffer[_required-8], 0xff, 8));
 722 
 723   _new_set = new (buffer) ImmutableOopMapSet(_set, _required);
 724   fill(_new_set, _required);
 725 
 726   DEBUG_ONLY(verify(buffer, _required, _new_set));
 727 
 728   return _new_set;
 729 }
 730 
 731 ImmutableOopMapSet* ImmutableOopMapBuilder::build() {
 732   _required = heap_size();
 733 
 734   // We need to allocate a chunk big enough to hold the ImmutableOopMapSet and all of its ImmutableOopMaps
 735   address buffer = (address) NEW_C_HEAP_ARRAY(unsigned char, _required, mtCode);
 736   return generate_into(buffer);
 737 }
 738 
 739 ImmutableOopMapSet* ImmutableOopMapSet::build_from(const OopMapSet* oopmap_set) {
 740   ResourceMark mark;
 741   ImmutableOopMapBuilder builder(oopmap_set);
 742   return builder.build();
 743 }
 744 
 745 
 746 //------------------------------DerivedPointerTable---------------------------
 747 
 748 #if COMPILER2_OR_JVMCI
 749 
 750 class DerivedPointerTable::Entry : public CHeapObj<mtCompiler> {
 751   oop* _location;   // Location of derived pointer, also pointing to base
 752   intptr_t _offset; // Offset from base pointer
 753   Entry* volatile _next;
 754 
 755   static Entry* volatile* next_ptr(Entry& entry) { return &entry._next; }
 756 
 757 public:
 758   Entry(oop* location, intptr_t offset) :
 759     _location(location), _offset(offset), _next(NULL) {}
 760 
 761   oop* location() const { return _location; }
 762   intptr_t offset() const { return _offset; }
 763   Entry* next() const { return _next; }
 764 
 765   typedef LockFreeStack<Entry, &next_ptr> List;
 766   static List* _list;
 767 };
 768 
 769 DerivedPointerTable::Entry::List* DerivedPointerTable::Entry::_list = NULL;
 770 bool DerivedPointerTable::_active = false;
 771 
 772 bool DerivedPointerTable::is_empty() {
 773   return Entry::_list == NULL || Entry::_list->empty();
 774 }
 775 
 776 void DerivedPointerTable::clear() {
 777   // The first time, we create the list.  Otherwise it should be
 778   // empty.  If not, then we have probably forgotton to call
 779   // update_pointers after last GC/Scavenge.
 780   assert (!_active, "should not be active");
 781   assert(is_empty(), "table not empty");
 782   if (Entry::_list == NULL) {
 783     void* mem = NEW_C_HEAP_OBJ(Entry::List, mtCompiler);
 784     Entry::_list = ::new (mem) Entry::List();
 785   }
 786   _active = true;
 787 }
 788 
 789 // Returns value of location as an int
 790 inline intptr_t value_of_loc(oop *pointer) {
 791   return cast_from_oop<intptr_t>((*pointer));
 792 }
 793 
 794 void DerivedPointerTable::add(oop *derived_loc, oop *base_loc) {
 795   assert(Universe::heap()->is_in_or_null(*base_loc), "not an oop");
 796   assert(derived_loc != base_loc, "Base and derived in same location");
 797   if (_active) {
 798     assert(*derived_loc != (void*)base_loc, "location already added");
 799     assert(Entry::_list != NULL, "list must exist");
 800     intptr_t offset = value_of_loc(derived_loc) - value_of_loc(base_loc);
 801     // This assert is invalid because derived pointers can be
 802     // arbitrarily far away from their base.
 803     // assert(offset >= -1000000, "wrong derived pointer info");
 804 
 805     if (TraceDerivedPointers) {
 806       tty->print_cr(
 807         "Add derived pointer@" INTPTR_FORMAT
 808         " - Derived: " INTPTR_FORMAT
 809         " Base: " INTPTR_FORMAT " (@" INTPTR_FORMAT ") (Offset: " INTX_FORMAT ")",
 810         p2i(derived_loc), p2i((address)*derived_loc), p2i((address)*base_loc), p2i(base_loc), offset
 811       );
 812     }
 813     // Set derived oop location to point to base.
 814     *derived_loc = (oop)base_loc;
 815     Entry* entry = new Entry(derived_loc, offset);
 816     Entry::_list->push(*entry);
 817   }
 818 }
 819 
 820 void DerivedPointerTable::update_pointers() {
 821   assert(Entry::_list != NULL, "list must exist");
 822   Entry* entries = Entry::_list->pop_all();
 823   while (entries != NULL) {
 824     Entry* entry = entries;
 825     entries = entry->next();
 826     oop* derived_loc = entry->location();
 827     intptr_t offset  = entry->offset();
 828     // The derived oop was setup to point to location of base
 829     oop base = **(oop**)derived_loc;
 830     assert(Universe::heap()->is_in_or_null(base), "must be an oop");
 831 
 832     *derived_loc = (oop)(((address)base) + offset);
 833     assert(value_of_loc(derived_loc) - value_of_loc(&base) == offset, "sanity check");
 834 
 835     if (TraceDerivedPointers) {
 836       tty->print_cr("Updating derived pointer@" INTPTR_FORMAT
 837                     " - Derived: " INTPTR_FORMAT "  Base: " INTPTR_FORMAT " (Offset: " INTX_FORMAT ")",
 838           p2i(derived_loc), p2i((address)*derived_loc), p2i((address)base), offset);
 839     }
 840 
 841     // Delete entry
 842     delete entry;
 843   }
 844   assert(Entry::_list->empty(), "invariant");
 845   _active = false;
 846 }
 847 
 848 #endif // COMPILER2_OR_JVMCI