1 /*
   2  * Copyright (c) 1998, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "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 "runtime/frame.inline.hpp"
  36 #include "runtime/handles.inline.hpp"
  37 #include "runtime/signature.hpp"
  38 #include "utilities/align.hpp"
  39 #ifdef COMPILER1
  40 #include "c1/c1_Defs.hpp"
  41 #endif
  42 #ifdef COMPILER2
  43 #include "opto/optoreg.hpp"
  44 #endif
  45 
  46 // OopMapStream
  47 
  48 OopMapStream::OopMapStream(OopMap* oop_map, int oop_types_mask) {
  49   _stream = new CompressedReadStream(oop_map->write_stream()->buffer());
  50   _mask = oop_types_mask;
  51   _size = oop_map->omv_count();
  52   _position = 0;
  53   _valid_omv = false;
  54 }
  55 
  56 OopMapStream::OopMapStream(const ImmutableOopMap* oop_map, int oop_types_mask) {
  57   _stream = new CompressedReadStream(oop_map->data_addr());
  58   _mask = oop_types_mask;
  59   _size = oop_map->count();
  60   _position = 0;
  61   _valid_omv = false;
  62 }
  63 
  64 void OopMapStream::find_next() {
  65   while(_position++ < _size) {
  66     _omv.read_from(_stream);
  67     if(((int)_omv.type() & _mask) > 0) {
  68       _valid_omv = true;
  69       return;
  70     }
  71   }
  72   _valid_omv = false;
  73 }
  74 
  75 
  76 // OopMap
  77 
  78 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
  79 // slots to hold 4-byte values like ints and floats in the LP64 build.
  80 OopMap::OopMap(int frame_size, int arg_count) {
  81   // OopMaps are usually quite so small, so pick a small initial size
  82   set_write_stream(new CompressedWriteStream(32));
  83   set_omv_count(0);
  84 
  85 #ifdef ASSERT
  86   _locs_length = VMRegImpl::stack2reg(0)->value() + frame_size + arg_count;
  87   _locs_used   = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
  88   for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
  89 #endif
  90 }
  91 
  92 
  93 OopMap::OopMap(OopMap::DeepCopyToken, OopMap* source) {
  94   // This constructor does a deep copy
  95   // of the source OopMap.
  96   set_write_stream(new CompressedWriteStream(source->omv_count() * 2));
  97   set_omv_count(0);
  98   set_offset(source->offset());
  99 
 100 #ifdef ASSERT
 101   _locs_length = source->_locs_length;
 102   _locs_used = NEW_RESOURCE_ARRAY(OopMapValue::oop_types, _locs_length);
 103   for(int i = 0; i < _locs_length; i++) _locs_used[i] = OopMapValue::unused_value;
 104 #endif
 105 
 106   // We need to copy the entries too.
 107   for (OopMapStream oms(source); !oms.is_done(); oms.next()) {
 108     OopMapValue omv = oms.current();
 109     omv.write_on(write_stream());
 110     increment_count();
 111   }
 112 }
 113 
 114 
 115 OopMap* OopMap::deep_copy() {
 116   return new OopMap(_deep_copy_token, this);
 117 }
 118 
 119 void OopMap::copy_data_to(address addr) const {
 120   memcpy(addr, write_stream()->buffer(), write_stream()->position());
 121 }
 122 
 123 int OopMap::heap_size() const {
 124   int size = sizeof(OopMap);
 125   int align = sizeof(void *) - 1;
 126   size += write_stream()->position();
 127   // Align to a reasonable ending point
 128   size = ((size+align) & ~align);
 129   return size;
 130 }
 131 
 132 // frame_size units are stack-slots (4 bytes) NOT intptr_t; we can name odd
 133 // slots to hold 4-byte values like ints and floats in the LP64 build.
 134 void OopMap::set_xxx(VMReg reg, OopMapValue::oop_types x, VMReg optional) {
 135 
 136   assert(reg->value() < _locs_length, "too big reg value for stack size");
 137   assert( _locs_used[reg->value()] == OopMapValue::unused_value, "cannot insert twice" );
 138   debug_only( _locs_used[reg->value()] = x; )
 139 
 140   OopMapValue o(reg, x);
 141 
 142   if(x == OopMapValue::callee_saved_value) {
 143     // This can never be a stack location, so we don't need to transform it.
 144     assert(optional->is_reg(), "Trying to callee save a stack location");
 145     o.set_content_reg(optional);
 146   } else if(x == OopMapValue::derived_oop_value) {
 147     o.set_content_reg(optional);
 148   }
 149 
 150   o.write_on(write_stream());
 151   increment_count();
 152 }
 153 
 154 
 155 void OopMap::set_oop(VMReg reg) {
 156   set_xxx(reg, OopMapValue::oop_value, VMRegImpl::Bad());
 157 }
 158 
 159 
 160 void OopMap::set_value(VMReg reg) {
 161   // At this time, we don't need value entries in our OopMap.
 162 }
 163 
 164 
 165 void OopMap::set_narrowoop(VMReg reg) {
 166   set_xxx(reg, OopMapValue::narrowoop_value, VMRegImpl::Bad());
 167 }
 168 
 169 
 170 void OopMap::set_callee_saved(VMReg reg, VMReg caller_machine_register ) {
 171   set_xxx(reg, OopMapValue::callee_saved_value, caller_machine_register);
 172 }
 173 
 174 
 175 void OopMap::set_derived_oop(VMReg reg, VMReg derived_from_local_register ) {
 176   if( reg == derived_from_local_register ) {
 177     // Actually an oop, derived shares storage with base,
 178     set_oop(reg);
 179   } else {
 180     set_xxx(reg, OopMapValue::derived_oop_value, derived_from_local_register);
 181   }
 182 }
 183 
 184 // OopMapSet
 185 
 186 OopMapSet::OopMapSet() {
 187   set_om_size(MinOopMapAllocation);
 188   set_om_count(0);
 189   OopMap** temp = NEW_RESOURCE_ARRAY(OopMap*, om_size());
 190   set_om_data(temp);
 191 }
 192 
 193 
 194 void OopMapSet::grow_om_data() {
 195   int new_size = om_size() * 2;
 196   OopMap** new_data = NEW_RESOURCE_ARRAY(OopMap*, new_size);
 197   memcpy(new_data,om_data(),om_size() * sizeof(OopMap*));
 198   set_om_size(new_size);
 199   set_om_data(new_data);
 200 }
 201 
 202 void OopMapSet::add_gc_map(int pc_offset, OopMap *map ) {
 203   assert(om_size() != -1,"Cannot grow a fixed OopMapSet");
 204 
 205   if(om_count() >= om_size()) {
 206     grow_om_data();
 207   }
 208   map->set_offset(pc_offset);
 209 
 210 #ifdef ASSERT
 211   if(om_count() > 0) {
 212     OopMap* last = at(om_count()-1);
 213     if (last->offset() == map->offset() ) {
 214       fatal("OopMap inserted twice");
 215     }
 216     if(last->offset() > map->offset()) {
 217       tty->print_cr( "WARNING, maps not sorted: pc[%d]=%d, pc[%d]=%d",
 218                       om_count(),last->offset(),om_count()+1,map->offset());
 219     }
 220   }
 221 #endif // ASSERT
 222 
 223   set(om_count(),map);
 224   increment_count();
 225 }
 226 
 227 
 228 int OopMapSet::heap_size() const {
 229   // The space we use
 230   int size = sizeof(OopMap);
 231   int align = sizeof(void *) - 1;
 232   size = ((size+align) & ~align);
 233   size += om_count() * sizeof(OopMap*);
 234 
 235   // Now add in the space needed for the indivdiual OopMaps
 236   for(int i=0; i < om_count(); i++) {
 237     size += at(i)->heap_size();
 238   }
 239   // We don't need to align this, it will be naturally pointer aligned
 240   return size;
 241 }
 242 
 243 
 244 OopMap* OopMapSet::singular_oop_map() {
 245   guarantee(om_count() == 1, "Make sure we only have a single gc point");
 246   return at(0);
 247 }
 248 
 249 
 250 OopMap* OopMapSet::find_map_at_offset(int pc_offset) const {
 251   int i, len = om_count();
 252   assert( len > 0, "must have pointer maps" );
 253 
 254   // Scan through oopmaps. Stop when current offset is either equal or greater
 255   // than the one we are looking for.
 256   for( i = 0; i < len; i++) {
 257     if( at(i)->offset() >= pc_offset )
 258       break;
 259   }
 260 
 261   assert( i < len, "oopmap not found" );
 262 
 263   OopMap* m = at(i);
 264   assert( m->offset() == pc_offset, "oopmap not found" );
 265   return m;
 266 }
 267 
 268 static void add_derived_oop(oop* base, oop* derived) {
 269 #if !defined(TIERED) && !INCLUDE_JVMCI
 270   COMPILER1_PRESENT(ShouldNotReachHere();)
 271 #endif // !defined(TIERED) && !INCLUDE_JVMCI
 272 #if COMPILER2_OR_JVMCI
 273   DerivedPointerTable::add(derived, base);
 274 #endif // COMPILER2_OR_JVMCI
 275 }
 276 
 277 
 278 #ifndef PRODUCT
 279 static void trace_codeblob_maps(const frame *fr, const RegisterMap *reg_map) {
 280   // Print oopmap and regmap
 281   tty->print_cr("------ ");
 282   CodeBlob* cb = fr->cb();
 283   const ImmutableOopMapSet* maps = cb->oop_maps();
 284   const ImmutableOopMap* map = cb->oop_map_for_return_address(fr->pc());
 285   map->print();
 286   if( cb->is_nmethod() ) {
 287     nmethod* nm = (nmethod*)cb;
 288     // native wrappers have no scope data, it is implied
 289     if (nm->is_native_method()) {
 290       tty->print("bci: 0 (native)");
 291     } else {
 292       ScopeDesc* scope  = nm->scope_desc_at(fr->pc());
 293       tty->print("bci: %d ",scope->bci());
 294     }
 295   }
 296   tty->cr();
 297   fr->print_on(tty);
 298   tty->print("     ");
 299   cb->print_value_on(tty);  tty->cr();
 300   reg_map->print();
 301   tty->print_cr("------ ");
 302 
 303 }
 304 #endif // PRODUCT
 305 
 306 void OopMapSet::oops_do(const frame *fr, const RegisterMap* reg_map, OopClosure* f) {
 307   // add derived oops to a table
 308   all_do(fr, reg_map, f, add_derived_oop, &do_nothing_cl);
 309 }
 310 
 311 
 312 void OopMapSet::all_do(const frame *fr, const RegisterMap *reg_map,
 313                        OopClosure* oop_fn, void derived_oop_fn(oop*, oop*),
 314                        OopClosure* value_fn) {
 315   CodeBlob* cb = fr->cb();
 316   assert(cb != NULL, "no codeblob");
 317 
 318   NOT_PRODUCT(if (TraceCodeBlobStacks) trace_codeblob_maps(fr, reg_map);)
 319 
 320   const ImmutableOopMapSet* maps = cb->oop_maps();
 321   const ImmutableOopMap* map = cb->oop_map_for_return_address(fr->pc());
 322   assert(map != NULL, "no ptr map found");
 323 
 324   // handle derived pointers first (otherwise base pointer may be
 325   // changed before derived pointer offset has been collected)
 326   OopMapValue omv;
 327   {
 328     OopMapStream oms(map,OopMapValue::derived_oop_value);
 329     if (!oms.is_done()) {
 330 #ifndef TIERED
 331       COMPILER1_PRESENT(ShouldNotReachHere();)
 332 #if INCLUDE_JVMCI
 333       if (UseJVMCICompiler) {
 334         ShouldNotReachHere();
 335       }
 336 #endif
 337 #endif // !TIERED
 338       // Protect the operation on the derived pointers.  This
 339       // protects the addition of derived pointers to the shared
 340       // derived pointer table in DerivedPointerTable::add().
 341       MutexLockerEx x(DerivedPointerTableGC_lock, Mutex::_no_safepoint_check_flag);
 342       do {
 343         omv = oms.current();
 344         oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
 345         guarantee(loc != NULL, "missing saved register");
 346         oop *derived_loc = loc;
 347         oop *base_loc    = fr->oopmapreg_to_location(omv.content_reg(), reg_map);
 348         // Ignore NULL oops and decoded NULL narrow oops which
 349         // equal to Universe::narrow_oop_base when a narrow oop
 350         // implicit null check is used in compiled code.
 351         // The narrow_oop_base could be NULL or be the address
 352         // of the page below heap depending on compressed oops mode.
 353         if (base_loc != NULL && *base_loc != (oop)NULL && !Universe::is_narrow_oop_base(*base_loc)) {
 354           derived_oop_fn(base_loc, derived_loc);
 355         }
 356         oms.next();
 357       }  while (!oms.is_done());
 358     }
 359   }
 360 
 361   // We want coop and oop oop_types
 362   int mask = OopMapValue::oop_value | OopMapValue::narrowoop_value;
 363   {
 364     for (OopMapStream oms(map,mask); !oms.is_done(); oms.next()) {
 365       omv = oms.current();
 366       oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
 367       // It should be an error if no location can be found for a
 368       // register mentioned as contained an oop of some kind.  Maybe
 369       // this was allowed previously because value_value items might
 370       // be missing?
 371       guarantee(loc != NULL, "missing saved register");
 372       if ( omv.type() == OopMapValue::oop_value ) {
 373         oop val = *loc;
 374         if (val == (oop)NULL || Universe::is_narrow_oop_base(val)) {
 375           // Ignore NULL oops and decoded NULL narrow oops which
 376           // equal to Universe::narrow_oop_base when a narrow oop
 377           // implicit null check is used in compiled code.
 378           // The narrow_oop_base could be NULL or be the address
 379           // of the page below heap depending on compressed oops mode.
 380           continue;
 381         }
 382 #ifdef ASSERT
 383         // We can not verify the oop here if we are using ZGC, the oop
 384         // will be bad in case we had a safepoint between a load and a
 385         // load barrier.
 386         if (!UseZGC &&
 387             ((((uintptr_t)loc & (sizeof(*loc)-1)) != 0) ||
 388              !Universe::heap()->is_in_or_null(*loc))) {
 389           tty->print_cr("# Found non oop pointer.  Dumping state at failure");
 390           // try to dump out some helpful debugging information
 391           trace_codeblob_maps(fr, reg_map);
 392           omv.print();
 393           tty->print_cr("register r");
 394           omv.reg()->print();
 395           tty->print_cr("loc = %p *loc = %p\n", loc, (address)*loc);
 396           // do the real assert.
 397           assert(Universe::heap()->is_in_or_null(*loc), "found non oop pointer");
 398         }
 399 #endif // ASSERT
 400         oop_fn->do_oop(loc);
 401       } else if ( omv.type() == OopMapValue::narrowoop_value ) {
 402         narrowOop *nl = (narrowOop*)loc;
 403 #ifndef VM_LITTLE_ENDIAN
 404         VMReg vmReg = omv.reg();
 405         // Don't do this on SPARC float registers as they can be individually addressed
 406         if (!vmReg->is_stack() SPARC_ONLY(&& !vmReg->is_FloatRegister())) {
 407           // compressed oops in registers only take up 4 bytes of an
 408           // 8 byte register but they are in the wrong part of the
 409           // word so adjust loc to point at the right place.
 410           nl = (narrowOop*)((address)nl + 4);
 411         }
 412 #endif
 413         oop_fn->do_oop(nl);
 414       }
 415     }
 416   }
 417 }
 418 
 419 
 420 // Update callee-saved register info for the following frame
 421 void OopMapSet::update_register_map(const frame *fr, RegisterMap *reg_map) {
 422   ResourceMark rm;
 423   CodeBlob* cb = fr->cb();
 424   assert(cb != NULL, "no codeblob");
 425 
 426   // Any reg might be saved by a safepoint handler (see generate_handler_blob).
 427   assert( reg_map->_update_for_id == NULL || fr->is_older(reg_map->_update_for_id),
 428          "already updated this map; do not 'update' it twice!" );
 429   debug_only(reg_map->_update_for_id = fr->id());
 430 
 431   // Check if caller must update oop argument
 432   assert((reg_map->include_argument_oops() ||
 433           !cb->caller_must_gc_arguments(reg_map->thread())),
 434          "include_argument_oops should already be set");
 435 
 436   // Scan through oopmap and find location of all callee-saved registers
 437   // (we do not do update in place, since info could be overwritten)
 438 
 439   address pc = fr->pc();
 440   const ImmutableOopMap* map  = cb->oop_map_for_return_address(pc);
 441   assert(map != NULL, "no ptr map found");
 442   DEBUG_ONLY(int nof_callee = 0;)
 443 
 444   for (OopMapStream oms(map, OopMapValue::callee_saved_value); !oms.is_done(); oms.next()) {
 445     OopMapValue omv = oms.current();
 446     VMReg reg = omv.content_reg();
 447     oop* loc = fr->oopmapreg_to_location(omv.reg(), reg_map);
 448     reg_map->set_location(reg, (address) loc);
 449     DEBUG_ONLY(nof_callee++;)
 450   }
 451 
 452   // Check that runtime stubs save all callee-saved registers
 453 #ifdef COMPILER2
 454   assert(cb->is_compiled_by_c1() || cb->is_compiled_by_jvmci() || !cb->is_runtime_stub() ||
 455          (nof_callee >= SAVED_ON_ENTRY_REG_COUNT || nof_callee >= C_SAVED_ON_ENTRY_REG_COUNT),
 456          "must save all");
 457 #endif // COMPILER2
 458 }
 459 
 460 //=============================================================================
 461 // Non-Product code
 462 
 463 #ifndef PRODUCT
 464 
 465 bool ImmutableOopMap::has_derived_pointer() const {
 466 #if !defined(TIERED) && !INCLUDE_JVMCI
 467   COMPILER1_PRESENT(return false);
 468 #endif // !TIERED
 469 #if COMPILER2_OR_JVMCI
 470   OopMapStream oms(this,OopMapValue::derived_oop_value);
 471   return oms.is_done();
 472 #else
 473   return false;
 474 #endif // COMPILER2_OR_JVMCI
 475 }
 476 
 477 #endif //PRODUCT
 478 
 479 // Printing code is present in product build for -XX:+PrintAssembly.
 480 
 481 static
 482 void print_register_type(OopMapValue::oop_types x, VMReg optional,
 483                          outputStream* st) {
 484   switch( x ) {
 485   case OopMapValue::oop_value:
 486     st->print("Oop");
 487     break;
 488   case OopMapValue::narrowoop_value:
 489     st->print("NarrowOop");
 490     break;
 491   case OopMapValue::callee_saved_value:
 492     st->print("Callers_");
 493     optional->print_on(st);
 494     break;
 495   case OopMapValue::derived_oop_value:
 496     st->print("Derived_oop_");
 497     optional->print_on(st);
 498     break;
 499   default:
 500     ShouldNotReachHere();
 501   }
 502 }
 503 
 504 void OopMapValue::print_on(outputStream* st) const {
 505   reg()->print_on(st);
 506   st->print("=");
 507   print_register_type(type(),content_reg(),st);
 508   st->print(" ");
 509 }
 510 
 511 void ImmutableOopMap::print_on(outputStream* st) const {
 512   OopMapValue omv;
 513   st->print("ImmutableOopMap{");
 514   for(OopMapStream oms(this); !oms.is_done(); oms.next()) {
 515     omv = oms.current();
 516     omv.print_on(st);
 517   }
 518   st->print("}");
 519 }
 520 
 521 void OopMap::print_on(outputStream* st) const {
 522   OopMapValue omv;
 523   st->print("OopMap{");
 524   for(OopMapStream oms((OopMap*)this); !oms.is_done(); oms.next()) {
 525     omv = oms.current();
 526     omv.print_on(st);
 527   }
 528   st->print("off=%d}", (int) offset());
 529 }
 530 
 531 void ImmutableOopMapSet::print_on(outputStream* st) const {
 532   const ImmutableOopMap* last = NULL;
 533   for (int i = 0; i < _count; ++i) {
 534     const ImmutableOopMapPair* pair = pair_at(i);
 535     const ImmutableOopMap* map = pair->get_from(this);
 536     if (map != last) {
 537       st->cr();
 538       map->print_on(st);
 539       st->print("pc offsets: ");
 540     }
 541     last = map;
 542     st->print("%d ", pair->pc_offset());
 543   }
 544 }
 545 
 546 void OopMapSet::print_on(outputStream* st) const {
 547   int i, len = om_count();
 548 
 549   st->print_cr("OopMapSet contains %d OopMaps\n",len);
 550 
 551   for( i = 0; i < len; i++) {
 552     OopMap* m = at(i);
 553     st->print_cr("#%d ",i);
 554     m->print_on(st);
 555     st->cr();
 556   }
 557 }
 558 
 559 bool OopMap::equals(const OopMap* other) const {
 560   if (other->_omv_count != _omv_count) {
 561     return false;
 562   }
 563   if (other->write_stream()->position() != write_stream()->position()) {
 564     return false;
 565   }
 566   if (memcmp(other->write_stream()->buffer(), write_stream()->buffer(), write_stream()->position()) != 0) {
 567     return false;
 568   }
 569   return true;
 570 }
 571 
 572 const ImmutableOopMap* ImmutableOopMapSet::find_map_at_offset(int pc_offset) const {
 573   ImmutableOopMapPair* pairs = get_pairs();
 574 
 575   int i;
 576   for (i = 0; i < _count; ++i) {
 577     if (pairs[i].pc_offset() >= pc_offset) {
 578       break;
 579     }
 580   }
 581   ImmutableOopMapPair* last = &pairs[i];
 582 
 583   assert(last->pc_offset() == pc_offset, "oopmap not found");
 584   return last->get_from(this);
 585 }
 586 
 587 const ImmutableOopMap* ImmutableOopMapPair::get_from(const ImmutableOopMapSet* set) const {
 588   return set->oopmap_at_offset(_oopmap_offset);
 589 }
 590 
 591 ImmutableOopMap::ImmutableOopMap(const OopMap* oopmap) : _count(oopmap->count()) {
 592   address addr = data_addr();
 593   oopmap->copy_data_to(addr);
 594 }
 595 
 596 #ifdef ASSERT
 597 int ImmutableOopMap::nr_of_bytes() const {
 598   OopMapStream oms(this);
 599 
 600   while (!oms.is_done()) {
 601     oms.next();
 602   }
 603   return sizeof(ImmutableOopMap) + oms.stream_position();
 604 }
 605 #endif
 606 
 607 ImmutableOopMapBuilder::ImmutableOopMapBuilder(const OopMapSet* set) : _set(set), _new_set(NULL), _empty(NULL), _last(NULL), _empty_offset(-1), _last_offset(-1), _offset(0), _required(-1) {
 608   _mapping = NEW_RESOURCE_ARRAY(Mapping, _set->size());
 609 }
 610 
 611 int ImmutableOopMapBuilder::size_for(const OopMap* map) const {
 612   return align_up((int)sizeof(ImmutableOopMap) + map->data_size(), 8);
 613 }
 614 
 615 int ImmutableOopMapBuilder::heap_size() {
 616   int base = sizeof(ImmutableOopMapSet);
 617   base = align_up(base, 8);
 618 
 619   // all of ours pc / offset pairs
 620   int pairs = _set->size() * sizeof(ImmutableOopMapPair);
 621   pairs = align_up(pairs, 8);
 622 
 623   for (int i = 0; i < _set->size(); ++i) {
 624     int size = 0;
 625     OopMap* map = _set->at(i);
 626 
 627     if (is_empty(map)) {
 628       /* only keep a single empty map in the set */
 629       if (has_empty()) {
 630         _mapping[i].set(Mapping::OOPMAP_EMPTY, _empty_offset, 0, map, _empty);
 631       } else {
 632         _empty_offset = _offset;
 633         _empty = map;
 634         size = size_for(map);
 635         _mapping[i].set(Mapping::OOPMAP_NEW, _offset, size, map);
 636       }
 637     } else if (is_last_duplicate(map)) {
 638       /* if this entry is identical to the previous one, just point it there */
 639       _mapping[i].set(Mapping::OOPMAP_DUPLICATE, _last_offset, 0, map, _last);
 640     } else {
 641       /* not empty, not an identical copy of the previous entry */
 642       size = size_for(map);
 643       _mapping[i].set(Mapping::OOPMAP_NEW, _offset, size, map);
 644       _last_offset = _offset;
 645       _last = map;
 646     }
 647 
 648     assert(_mapping[i]._map == map, "check");
 649     _offset += size;
 650   }
 651 
 652   int total = base + pairs + _offset;
 653   DEBUG_ONLY(total += 8);
 654   _required = total;
 655   return total;
 656 }
 657 
 658 void ImmutableOopMapBuilder::fill_pair(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set) {
 659   assert(offset < set->nr_of_bytes(), "check");
 660   new ((address) pair) ImmutableOopMapPair(map->offset(), offset);
 661 }
 662 
 663 int ImmutableOopMapBuilder::fill_map(ImmutableOopMapPair* pair, const OopMap* map, int offset, const ImmutableOopMapSet* set) {
 664   fill_pair(pair, map, offset, set);
 665   address addr = (address) pair->get_from(_new_set); // location of the ImmutableOopMap
 666 
 667   new (addr) ImmutableOopMap(map);
 668   return size_for(map);
 669 }
 670 
 671 void ImmutableOopMapBuilder::fill(ImmutableOopMapSet* set, int sz) {
 672   ImmutableOopMapPair* pairs = set->get_pairs();
 673 
 674   for (int i = 0; i < set->count(); ++i) {
 675     const OopMap* map = _mapping[i]._map;
 676     ImmutableOopMapPair* pair = NULL;
 677     int size = 0;
 678 
 679     if (_mapping[i]._kind == Mapping::OOPMAP_NEW) {
 680       size = fill_map(&pairs[i], map, _mapping[i]._offset, set);
 681     } else if (_mapping[i]._kind == Mapping::OOPMAP_DUPLICATE || _mapping[i]._kind == Mapping::OOPMAP_EMPTY) {
 682       fill_pair(&pairs[i], map, _mapping[i]._offset, set);
 683     }
 684 
 685     const ImmutableOopMap* nv = set->find_map_at_offset(map->offset());
 686     assert(memcmp(map->data(), nv->data_addr(), map->data_size()) == 0, "check identity");
 687   }
 688 }
 689 
 690 #ifdef ASSERT
 691 void ImmutableOopMapBuilder::verify(address buffer, int size, const ImmutableOopMapSet* set) {
 692   for (int i = 0; i < 8; ++i) {
 693     assert(buffer[size - 8 + i] == (unsigned char) 0xff, "overwritten memory check");
 694   }
 695 
 696   for (int i = 0; i < set->count(); ++i) {
 697     const ImmutableOopMapPair* pair = set->pair_at(i);
 698     assert(pair->oopmap_offset() < set->nr_of_bytes(), "check size");
 699     const ImmutableOopMap* map = pair->get_from(set);
 700     int nr_of_bytes = map->nr_of_bytes();
 701     assert(pair->oopmap_offset() + nr_of_bytes <= set->nr_of_bytes(), "check size + size");
 702   }
 703 }
 704 #endif
 705 
 706 ImmutableOopMapSet* ImmutableOopMapBuilder::generate_into(address buffer) {
 707   DEBUG_ONLY(memset(&buffer[_required-8], 0xff, 8));
 708 
 709   _new_set = new (buffer) ImmutableOopMapSet(_set, _required);
 710   fill(_new_set, _required);
 711 
 712   DEBUG_ONLY(verify(buffer, _required, _new_set));
 713 
 714   return _new_set;
 715 }
 716 
 717 ImmutableOopMapSet* ImmutableOopMapBuilder::build() {
 718   _required = heap_size();
 719 
 720   // We need to allocate a chunk big enough to hold the ImmutableOopMapSet and all of its ImmutableOopMaps
 721   address buffer = (address) NEW_C_HEAP_ARRAY(unsigned char, _required, mtCode);
 722   return generate_into(buffer);
 723 }
 724 
 725 ImmutableOopMapSet* ImmutableOopMapSet::build_from(const OopMapSet* oopmap_set) {
 726   ResourceMark mark;
 727   ImmutableOopMapBuilder builder(oopmap_set);
 728   return builder.build();
 729 }
 730 
 731 
 732 //------------------------------DerivedPointerTable---------------------------
 733 
 734 #if COMPILER2_OR_JVMCI
 735 
 736 class DerivedPointerEntry : public CHeapObj<mtCompiler> {
 737  private:
 738   oop*     _location; // Location of derived pointer (also pointing to the base)
 739   intptr_t _offset;   // Offset from base pointer
 740  public:
 741   DerivedPointerEntry(oop* location, intptr_t offset) { _location = location; _offset = offset; }
 742   oop* location()    { return _location; }
 743   intptr_t  offset() { return _offset; }
 744 };
 745 
 746 
 747 GrowableArray<DerivedPointerEntry*>* DerivedPointerTable::_list = NULL;
 748 bool DerivedPointerTable::_active = false;
 749 
 750 
 751 void DerivedPointerTable::clear() {
 752   // The first time, we create the list.  Otherwise it should be
 753   // empty.  If not, then we have probably forgotton to call
 754   // update_pointers after last GC/Scavenge.
 755   assert (!_active, "should not be active");
 756   assert(_list == NULL || _list->length() == 0, "table not empty");
 757   if (_list == NULL) {
 758     _list = new (ResourceObj::C_HEAP, mtCompiler) GrowableArray<DerivedPointerEntry*>(10, true); // Allocated on C heap
 759   }
 760   _active = true;
 761 }
 762 
 763 
 764 // Returns value of location as an int
 765 intptr_t value_of_loc(oop *pointer) { return cast_from_oop<intptr_t>((*pointer)); }
 766 
 767 
 768 void DerivedPointerTable::add(oop *derived_loc, oop *base_loc) {
 769   assert(Universe::heap()->is_in_or_null(*base_loc), "not an oop");
 770   assert(derived_loc != base_loc, "Base and derived in same location");
 771   if (_active) {
 772     assert(*derived_loc != (oop)base_loc, "location already added");
 773     assert(_list != NULL, "list must exist");
 774     intptr_t offset = value_of_loc(derived_loc) - value_of_loc(base_loc);
 775     // This assert is invalid because derived pointers can be
 776     // arbitrarily far away from their base.
 777     // assert(offset >= -1000000, "wrong derived pointer info");
 778 
 779     if (TraceDerivedPointers) {
 780       tty->print_cr(
 781         "Add derived pointer@" INTPTR_FORMAT
 782         " - Derived: " INTPTR_FORMAT
 783         " Base: " INTPTR_FORMAT " (@" INTPTR_FORMAT ") (Offset: " INTX_FORMAT ")",
 784         p2i(derived_loc), p2i((address)*derived_loc), p2i((address)*base_loc), p2i(base_loc), offset
 785       );
 786     }
 787     // Set derived oop location to point to base.
 788     *derived_loc = (oop)base_loc;
 789     assert_lock_strong(DerivedPointerTableGC_lock);
 790     DerivedPointerEntry *entry = new DerivedPointerEntry(derived_loc, offset);
 791     _list->append(entry);
 792   }
 793 }
 794 
 795 
 796 void DerivedPointerTable::update_pointers() {
 797   assert(_list != NULL, "list must exist");
 798   for(int i = 0; i < _list->length(); i++) {
 799     DerivedPointerEntry* entry = _list->at(i);
 800     oop* derived_loc = entry->location();
 801     intptr_t offset  = entry->offset();
 802     // The derived oop was setup to point to location of base
 803     oop  base        = **(oop**)derived_loc;
 804     assert(Universe::heap()->is_in_or_null(base), "must be an oop");
 805 
 806     *derived_loc = (oop)(((address)base) + offset);
 807     assert(value_of_loc(derived_loc) - value_of_loc(&base) == offset, "sanity check");
 808 
 809     if (TraceDerivedPointers) {
 810       tty->print_cr("Updating derived pointer@" INTPTR_FORMAT
 811                     " - Derived: " INTPTR_FORMAT "  Base: " INTPTR_FORMAT " (Offset: " INTX_FORMAT ")",
 812           p2i(derived_loc), p2i((address)*derived_loc), p2i((address)base), offset);
 813     }
 814 
 815     // Delete entry
 816     delete entry;
 817     _list->at_put(i, NULL);
 818   }
 819   // Clear list, so it is ready for next traversal (this is an invariant)
 820   if (TraceDerivedPointers && !_list->is_empty()) {
 821     tty->print_cr("--------------------------");
 822   }
 823   _list->clear();
 824   _active = false;
 825 }
 826 
 827 #endif // COMPILER2_OR_JVMCI