1 /*
   2  * Copyright (c) 1997, 2024, 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 "ci/ciUtilities.hpp"
  27 #include "code/codeCache.hpp"
  28 #include "code/compiledIC.hpp"
  29 #include "code/nmethod.hpp"
  30 #include "code/relocInfo.hpp"
  31 #include "code/SCCache.hpp"
  32 #include "memory/resourceArea.hpp"
  33 #include "memory/universe.hpp"
  34 #include "oops/compressedOops.inline.hpp"
  35 #include "oops/oop.inline.hpp"
  36 #include "runtime/flags/flagSetting.hpp"
  37 #include "runtime/stubCodeGenerator.hpp"
  38 #include "utilities/align.hpp"
  39 #include "utilities/checkedCast.hpp"
  40 #include "utilities/copy.hpp"
  41 
  42 #include <new>
  43 #include <type_traits>
  44 
  45 const RelocationHolder RelocationHolder::none; // its type is relocInfo::none
  46 
  47 
  48 // Implementation of relocInfo
  49 
  50 #ifdef ASSERT
  51 relocInfo::relocType relocInfo::check_relocType(relocType type) {
  52   assert(type != data_prefix_tag, "cannot build a prefix this way");
  53   assert((type & type_mask) == type, "wrong type");
  54   return type;
  55 }
  56 
  57 void relocInfo::check_offset_and_format(int offset, int format) {
  58   assert(offset >= 0 && offset < offset_limit(), "offset out off bounds");
  59   assert(is_aligned(offset, offset_unit), "misaligned offset");
  60   assert((format & format_mask) == format, "wrong format");
  61 }
  62 #endif // ASSERT
  63 
  64 void relocInfo::initialize(CodeSection* dest, Relocation* reloc) {
  65   relocInfo* data = this+1;  // here's where the data might go
  66   dest->set_locs_end(data);  // sync end: the next call may read dest.locs_end
  67   reloc->pack_data_to(dest); // maybe write data into locs, advancing locs_end
  68   relocInfo* data_limit = dest->locs_end();
  69   if (data_limit > data) {
  70     relocInfo suffix = (*this);
  71     data_limit = this->finish_prefix((short*) data_limit);
  72     // Finish up with the suffix.  (Hack note: pack_data_to might edit this.)
  73     *data_limit = suffix;
  74     dest->set_locs_end(data_limit+1);
  75   }
  76 }
  77 
  78 relocInfo* relocInfo::finish_prefix(short* prefix_limit) {
  79   assert(sizeof(relocInfo) == sizeof(short), "change this code");
  80   short* p = (short*)(this+1);
  81   assert(prefix_limit >= p, "must be a valid span of data");
  82   int plen = checked_cast<int>(prefix_limit - p);
  83   if (plen == 0) {
  84     debug_only(_value = 0xFFFF);
  85     return this;                         // no data: remove self completely
  86   }
  87   if (plen == 1 && fits_into_immediate(p[0])) {
  88     (*this) = immediate_relocInfo(p[0]); // move data inside self
  89     return this+1;
  90   }
  91   // cannot compact, so just update the count and return the limit pointer
  92   (*this) = prefix_info(plen);       // write new datalen
  93   assert(data() + datalen() == prefix_limit, "pointers must line up");
  94   return (relocInfo*)prefix_limit;
  95 }
  96 
  97 void relocInfo::set_type(relocType t) {
  98   int old_offset = addr_offset();
  99   int old_format = format();
 100   (*this) = relocInfo(t, old_offset, old_format);
 101   assert(type()==(int)t, "sanity check");
 102   assert(addr_offset()==old_offset, "sanity check");
 103   assert(format()==old_format, "sanity check");
 104 }
 105 
 106 void relocInfo::change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type) {
 107   bool found = false;
 108   while (itr->next() && !found) {
 109     if (itr->addr() == pc) {
 110       assert(itr->type()==old_type, "wrong relocInfo type found");
 111       itr->current()->set_type(new_type);
 112       found=true;
 113     }
 114   }
 115   assert(found, "no relocInfo found for pc");
 116 }
 117 
 118 
 119 // ----------------------------------------------------------------------------------------------------
 120 // Implementation of RelocIterator
 121 
 122 void RelocIterator::initialize(nmethod* nm, address begin, address limit) {
 123   initialize_misc();
 124 
 125   if (nm == nullptr && begin != nullptr) {
 126     // allow nmethod to be deduced from beginning address
 127     CodeBlob* cb = CodeCache::find_blob(begin);
 128     nm = (cb != nullptr) ? cb->as_nmethod_or_null() : nullptr;
 129   }
 130   guarantee(nm != nullptr, "must be able to deduce nmethod from other arguments");
 131 
 132   _code    = nm;
 133   _current = nm->relocation_begin() - 1;
 134   _end     = nm->relocation_end();
 135   _addr    = nm->content_begin();
 136 
 137   // Initialize code sections.
 138   _section_start[CodeBuffer::SECT_CONSTS] = nm->consts_begin();
 139   _section_start[CodeBuffer::SECT_INSTS ] = nm->insts_begin() ;
 140   _section_start[CodeBuffer::SECT_STUBS ] = nm->stub_begin()  ;
 141 
 142   _section_end  [CodeBuffer::SECT_CONSTS] = nm->consts_end()  ;
 143   _section_end  [CodeBuffer::SECT_INSTS ] = nm->insts_end()   ;
 144   _section_end  [CodeBuffer::SECT_STUBS ] = nm->stub_end()    ;
 145 
 146   assert(!has_current(), "just checking");
 147   assert(begin == nullptr || begin >= nm->code_begin(), "in bounds");
 148   assert(limit == nullptr || limit <= nm->code_end(),   "in bounds");
 149   set_limits(begin, limit);
 150 }
 151 
 152 
 153 RelocIterator::RelocIterator(CodeSection* cs, address begin, address limit) {
 154   initialize_misc();
 155   assert(((cs->locs_start() != nullptr) && (cs->locs_end() != nullptr)), "valid start and end pointer");
 156   _current = cs->locs_start()-1;
 157   _end     = cs->locs_end();
 158   _addr    = cs->start();
 159   _code    = nullptr; // Not cb->blob();
 160 
 161   CodeBuffer* cb = cs->outer();
 162   assert((int) SECT_LIMIT == CodeBuffer::SECT_LIMIT, "my copy must be equal");
 163   for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {
 164     CodeSection* cs = cb->code_section(n);
 165     _section_start[n] = cs->start();
 166     _section_end  [n] = cs->end();
 167   }
 168 
 169   assert(!has_current(), "just checking");
 170 
 171   assert(begin == nullptr || begin >= cs->start(), "in bounds");
 172   assert(limit == nullptr || limit <= cs->end(),   "in bounds");
 173   set_limits(begin, limit);
 174 }
 175 
 176 bool RelocIterator::addr_in_const() const {
 177   const int n = CodeBuffer::SECT_CONSTS;
 178   if (_section_start[n] == nullptr) {
 179     return false;
 180   }
 181   return section_start(n) <= addr() && addr() < section_end(n);
 182 }
 183 
 184 
 185 void RelocIterator::set_limits(address begin, address limit) {
 186   _limit = limit;
 187 
 188   // the limit affects this next stuff:
 189   if (begin != nullptr) {
 190     relocInfo* backup;
 191     address    backup_addr;
 192     while (true) {
 193       backup      = _current;
 194       backup_addr = _addr;
 195       if (!next() || addr() >= begin) break;
 196     }
 197     // At this point, either we are at the first matching record,
 198     // or else there is no such record, and !has_current().
 199     // In either case, revert to the immediately preceding state.
 200     _current = backup;
 201     _addr    = backup_addr;
 202     set_has_current(false);
 203   }
 204 }
 205 
 206 
 207 // All the strange bit-encodings are in here.
 208 // The idea is to encode relocation data which are small integers
 209 // very efficiently (a single extra halfword).  Larger chunks of
 210 // relocation data need a halfword header to hold their size.
 211 void RelocIterator::advance_over_prefix() {
 212   if (_current->is_datalen()) {
 213     _data    = (short*) _current->data();
 214     _datalen =          _current->datalen();
 215     _current += _datalen + 1;   // skip the embedded data & header
 216   } else {
 217     _databuf = _current->immediate();
 218     _data = &_databuf;
 219     _datalen = 1;
 220     _current++;                 // skip the header
 221   }
 222   // The client will see the following relocInfo, whatever that is.
 223   // It is the reloc to which the preceding data applies.
 224 }
 225 
 226 
 227 void RelocIterator::initialize_misc() {
 228   set_has_current(false);
 229   for (int i = (int) CodeBuffer::SECT_FIRST; i < (int) CodeBuffer::SECT_LIMIT; i++) {
 230     _section_start[i] = nullptr;  // these will be lazily computed, if needed
 231     _section_end  [i] = nullptr;
 232   }
 233 }
 234 
 235 
 236 Relocation* RelocIterator::reloc() {
 237   // (take the "switch" out-of-line)
 238   relocInfo::relocType t = type();
 239   if (false) {}
 240   #define EACH_TYPE(name)                             \
 241   else if (t == relocInfo::name##_type) {             \
 242     return name##_reloc();                            \
 243   }
 244   APPLY_TO_RELOCATIONS(EACH_TYPE);
 245   #undef EACH_TYPE
 246   assert(t == relocInfo::none, "must be padding");
 247   _rh = RelocationHolder::none;
 248   return _rh.reloc();
 249 }
 250 
 251 // Verify all the destructors are trivial, so we don't need to worry about
 252 // destroying old contents of a RelocationHolder being assigned or destroyed.
 253 #define VERIFY_TRIVIALLY_DESTRUCTIBLE_AUX(Reloc) \
 254   static_assert(std::is_trivially_destructible<Reloc>::value, "must be");
 255 
 256 #define VERIFY_TRIVIALLY_DESTRUCTIBLE(name) \
 257   VERIFY_TRIVIALLY_DESTRUCTIBLE_AUX(PASTE_TOKENS(name, _Relocation));
 258 
 259 APPLY_TO_RELOCATIONS(VERIFY_TRIVIALLY_DESTRUCTIBLE)
 260 VERIFY_TRIVIALLY_DESTRUCTIBLE_AUX(Relocation)
 261 
 262 #undef VERIFY_TRIVIALLY_DESTRUCTIBLE_AUX
 263 #undef VERIFY_TRIVIALLY_DESTRUCTIBLE
 264 
 265 // Define all the copy_into functions.  These rely on all Relocation types
 266 // being trivially destructible (verified above).  So it doesn't matter
 267 // whether the target holder has been previously initialized or not.  There's
 268 // no need to consider that distinction and destruct the relocation in an
 269 // already initialized holder.
 270 #define DEFINE_COPY_INTO_AUX(Reloc)                             \
 271   void Reloc::copy_into(RelocationHolder& holder) const {       \
 272     copy_into_helper(*this, holder);                            \
 273   }
 274 
 275 #define DEFINE_COPY_INTO(name) \
 276   DEFINE_COPY_INTO_AUX(PASTE_TOKENS(name, _Relocation))
 277 
 278 APPLY_TO_RELOCATIONS(DEFINE_COPY_INTO)
 279 DEFINE_COPY_INTO_AUX(Relocation)
 280 
 281 #undef DEFINE_COPY_INTO_AUX
 282 #undef DEFINE_COPY_INTO
 283 
 284 //////// Methods for flyweight Relocation types
 285 
 286 // some relocations can compute their own values
 287 address Relocation::value() {
 288   ShouldNotReachHere();
 289   return nullptr;
 290 }
 291 
 292 
 293 void Relocation::set_value(address x) {
 294   ShouldNotReachHere();
 295 }
 296 
 297 void Relocation::const_set_data_value(address x) {
 298 #ifdef _LP64
 299   if (format() == relocInfo::narrow_oop_in_const) {
 300     *(narrowOop*)addr() = CompressedOops::encode(cast_to_oop(x));
 301   } else {
 302 #endif
 303     *(address*)addr() = x;
 304 #ifdef _LP64
 305   }
 306 #endif
 307 }
 308 
 309 void Relocation::const_verify_data_value(address x) {
 310 #ifdef _LP64
 311   if (format() == relocInfo::narrow_oop_in_const) {
 312     guarantee(*(narrowOop*)addr() == CompressedOops::encode(cast_to_oop(x)), "must agree");
 313   } else {
 314 #endif
 315     guarantee(*(address*)addr() == x, "must agree");
 316 #ifdef _LP64
 317   }
 318 #endif
 319 }
 320 
 321 
 322 RelocationHolder Relocation::spec_simple(relocInfo::relocType rtype) {
 323   if (rtype == relocInfo::none)  return RelocationHolder::none;
 324   relocInfo ri = relocInfo(rtype, 0);
 325   RelocIterator itr;
 326   itr.set_current(ri);
 327   itr.reloc();
 328   return itr._rh;
 329 }
 330 
 331 address Relocation::old_addr_for(address newa,
 332                                  const CodeBuffer* src, CodeBuffer* dest) {
 333   int sect = dest->section_index_of(newa);
 334   guarantee(sect != CodeBuffer::SECT_NONE, "lost track of this address");
 335   address ostart = src->code_section(sect)->start();
 336   address nstart = dest->code_section(sect)->start();
 337   return ostart + (newa - nstart);
 338 }
 339 
 340 address Relocation::new_addr_for(address olda,
 341                                  const CodeBuffer* src, CodeBuffer* dest) {
 342   debug_only(const CodeBuffer* src0 = src);
 343   int sect = CodeBuffer::SECT_NONE;
 344   // Look for olda in the source buffer, and all previous incarnations
 345   // if the source buffer has been expanded.
 346   for (; src != nullptr; src = src->before_expand()) {
 347     sect = src->section_index_of(olda);
 348     if (sect != CodeBuffer::SECT_NONE)  break;
 349   }
 350   guarantee(sect != CodeBuffer::SECT_NONE, "lost track of this address");
 351   address ostart = src->code_section(sect)->start();
 352   address nstart = dest->code_section(sect)->start();
 353   return nstart + (olda - ostart);
 354 }
 355 
 356 void Relocation::normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections) {
 357   address addr0 = addr;
 358   if (addr0 == nullptr || dest->allocates2(addr0))  return;
 359   CodeBuffer* cb = dest->outer();
 360   addr = new_addr_for(addr0, cb, cb);
 361   assert(allow_other_sections || dest->contains2(addr),
 362          "addr must be in required section");
 363 }
 364 
 365 
 366 void CallRelocation::set_destination(address x) {
 367   pd_set_call_destination(x);
 368 }
 369 
 370 void CallRelocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
 371   // Usually a self-relative reference to an external routine.
 372   // On some platforms, the reference is absolute (not self-relative).
 373   // The enhanced use of pd_call_destination sorts this all out.
 374   address orig_addr = old_addr_for(addr(), src, dest);
 375   address callee    = pd_call_destination(orig_addr);
 376   // Reassert the callee address, this time in the new copy of the code.
 377   pd_set_call_destination(callee);
 378 }
 379 
 380 
 381 #ifdef USE_TRAMPOLINE_STUB_FIX_OWNER
 382 void trampoline_stub_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
 383   // Finalize owner destination only for nmethods
 384   if (dest->blob() != nullptr) return;
 385   pd_fix_owner_after_move();
 386 }
 387 #endif
 388 
 389 //// pack/unpack methods
 390 
 391 void oop_Relocation::pack_data_to(CodeSection* dest) {
 392   short* p = (short*) dest->locs_end();
 393   p = pack_1_int_to(p, _oop_index);
 394   dest->set_locs_end((relocInfo*) p);
 395 }
 396 
 397 
 398 void oop_Relocation::unpack_data() {
 399   _oop_index = unpack_1_int();
 400 }
 401 
 402 void metadata_Relocation::pack_data_to(CodeSection* dest) {
 403   short* p = (short*) dest->locs_end();
 404   p = pack_1_int_to(p, _metadata_index);
 405   dest->set_locs_end((relocInfo*) p);
 406 }
 407 
 408 
 409 void metadata_Relocation::unpack_data() {
 410   _metadata_index = unpack_1_int();
 411 }
 412 
 413 
 414 void virtual_call_Relocation::pack_data_to(CodeSection* dest) {
 415   short*  p     = (short*) dest->locs_end();
 416   address point =          dest->locs_point();
 417 
 418   normalize_address(_cached_value, dest);
 419   jint x0 = scaled_offset_null_special(_cached_value, point);
 420   p = pack_2_ints_to(p, x0, _method_index);
 421   dest->set_locs_end((relocInfo*) p);
 422 }
 423 
 424 
 425 void virtual_call_Relocation::unpack_data() {
 426   jint x0 = 0;
 427   unpack_2_ints(x0, _method_index);
 428   address point = addr();
 429   _cached_value = x0==0? nullptr: address_from_scaled_offset(x0, point);
 430 }
 431 
 432 void runtime_call_w_cp_Relocation::pack_data_to(CodeSection * dest) {
 433   short* p = pack_1_int_to((short *)dest->locs_end(), (jint)(_offset >> 2));
 434   dest->set_locs_end((relocInfo*) p);
 435 }
 436 
 437 void runtime_call_w_cp_Relocation::unpack_data() {
 438   _offset = unpack_1_int() << 2;
 439 }
 440 
 441 void static_stub_Relocation::pack_data_to(CodeSection* dest) {
 442   short* p = (short*) dest->locs_end();
 443   CodeSection* insts = dest->outer()->insts();
 444   normalize_address(_static_call, insts);
 445   p = pack_1_int_to(p, scaled_offset(_static_call, insts->start()));
 446   dest->set_locs_end((relocInfo*) p);
 447 }
 448 
 449 void static_stub_Relocation::unpack_data() {
 450   address base = binding()->section_start(CodeBuffer::SECT_INSTS);
 451   jint offset = unpack_1_int();
 452   _static_call = address_from_scaled_offset(offset, base);
 453 }
 454 
 455 void trampoline_stub_Relocation::pack_data_to(CodeSection* dest ) {
 456   short* p = (short*) dest->locs_end();
 457   CodeSection* insts = dest->outer()->insts();
 458   normalize_address(_owner, insts);
 459   p = pack_1_int_to(p, scaled_offset(_owner, insts->start()));
 460   dest->set_locs_end((relocInfo*) p);
 461 }
 462 
 463 void trampoline_stub_Relocation::unpack_data() {
 464   address base = binding()->section_start(CodeBuffer::SECT_INSTS);
 465   _owner = address_from_scaled_offset(unpack_1_int(), base);
 466 }
 467 
 468 void external_word_Relocation::pack_data_to(CodeSection* dest) {
 469   short* p = (short*) dest->locs_end();
 470   int index = ExternalsRecorder::find_index(_target);
 471   // Use 4 bytes to store index to be able patch it when
 472   // updating relocations in SCCReader::read_relocations().
 473   p = add_jint(p, index);
 474   dest->set_locs_end((relocInfo*) p);
 475 }
 476 
 477 void external_word_Relocation::unpack_data() {
 478   int index = unpack_1_int();
 479   _target = ExternalsRecorder::at(index);
 480 }
 481 
 482 
 483 void internal_word_Relocation::pack_data_to(CodeSection* dest) {
 484   short* p = (short*) dest->locs_end();
 485   normalize_address(_target, dest, true);
 486 
 487   // Check whether my target address is valid within this section.
 488   // If not, strengthen the relocation type to point to another section.
 489   int sindex = _section;
 490   if (sindex == CodeBuffer::SECT_NONE && _target != nullptr
 491       && (!dest->allocates(_target) || _target == dest->locs_point())) {
 492     sindex = dest->outer()->section_index_of(_target);
 493     guarantee(sindex != CodeBuffer::SECT_NONE, "must belong somewhere");
 494     relocInfo* base = dest->locs_end() - 1;
 495     assert(base->type() == this->type(), "sanity");
 496     // Change the written type, to be section_word_type instead.
 497     base->set_type(relocInfo::section_word_type);
 498   }
 499 
 500   // Note: An internal_word relocation cannot refer to its own instruction,
 501   // because we reserve "0" to mean that the pointer itself is embedded
 502   // in the code stream.  We use a section_word relocation for such cases.
 503 
 504   if (sindex == CodeBuffer::SECT_NONE) {
 505     assert(type() == relocInfo::internal_word_type, "must be base class");
 506     guarantee(_target == nullptr || dest->allocates2(_target), "must be within the given code section");
 507     jint x0 = scaled_offset_null_special(_target, dest->locs_point());
 508     assert(!(x0 == 0 && _target != nullptr), "correct encoding of null target");
 509     p = pack_1_int_to(p, x0);
 510   } else {
 511     assert(_target != nullptr, "sanity");
 512     CodeSection* sect = dest->outer()->code_section(sindex);
 513     guarantee(sect->allocates2(_target), "must be in correct section");
 514     address base = sect->start();
 515     jint offset = scaled_offset(_target, base);
 516     assert((uint)sindex < (uint)CodeBuffer::SECT_LIMIT, "sanity");
 517     assert(CodeBuffer::SECT_LIMIT <= (1 << section_width), "section_width++");
 518     p = pack_1_int_to(p, (offset << section_width) | sindex);
 519   }
 520 
 521   dest->set_locs_end((relocInfo*) p);
 522 }
 523 
 524 
 525 void internal_word_Relocation::unpack_data() {
 526   jint x0 = unpack_1_int();
 527   _target = x0==0? nullptr: address_from_scaled_offset(x0, addr());
 528   _section = CodeBuffer::SECT_NONE;
 529 }
 530 
 531 
 532 void section_word_Relocation::unpack_data() {
 533   jint    x      = unpack_1_int();
 534   jint    offset = (x >> section_width);
 535   int     sindex = (x & ((1<<section_width)-1));
 536   address base   = binding()->section_start(sindex);
 537 
 538   _section = sindex;
 539   _target  = address_from_scaled_offset(offset, base);
 540 }
 541 
 542 //// miscellaneous methods
 543 oop* oop_Relocation::oop_addr() {
 544   int n = _oop_index;
 545   if (n == 0) {
 546     // oop is stored in the code stream
 547     return (oop*) pd_address_in_code();
 548   } else {
 549     // oop is stored in table at nmethod::oops_begin
 550     return code()->oop_addr_at(n);
 551   }
 552 }
 553 
 554 
 555 oop oop_Relocation::oop_value() {
 556   // clean inline caches store a special pseudo-null
 557   if (Universe::contains_non_oop_word(oop_addr())) {
 558     return nullptr;
 559   }
 560   return *oop_addr();
 561 }
 562 
 563 
 564 void oop_Relocation::fix_oop_relocation() {
 565   if (!oop_is_immediate()) {
 566     // get the oop from the pool, and re-insert it into the instruction:
 567     set_value(value());
 568   }
 569 }
 570 
 571 
 572 void oop_Relocation::verify_oop_relocation() {
 573   if (!oop_is_immediate()) {
 574     // get the oop from the pool, and re-insert it into the instruction:
 575     verify_value(value());
 576   }
 577 }
 578 
 579 // meta data versions
 580 Metadata** metadata_Relocation::metadata_addr() {
 581   int n = _metadata_index;
 582   if (n == 0) {
 583     // metadata is stored in the code stream
 584     return (Metadata**) pd_address_in_code();
 585     } else {
 586     // metadata is stored in table at nmethod::metadatas_begin
 587     return code()->metadata_addr_at(n);
 588     }
 589   }
 590 
 591 
 592 Metadata* metadata_Relocation::metadata_value() {
 593   Metadata* v = *metadata_addr();
 594   // clean inline caches store a special pseudo-null
 595   if (v == (Metadata*)Universe::non_oop_word())  v = nullptr;
 596   return v;
 597   }
 598 
 599 
 600 void metadata_Relocation::fix_metadata_relocation() {
 601   if (!metadata_is_immediate()) {
 602     // get the metadata from the pool, and re-insert it into the instruction:
 603     pd_fix_value(value());
 604   }
 605 }
 606 
 607 address virtual_call_Relocation::cached_value() {
 608   assert(_cached_value != nullptr && _cached_value < addr(), "must precede ic_call");
 609   return _cached_value;
 610 }
 611 
 612 Method* virtual_call_Relocation::method_value() {
 613   nmethod* nm = code();
 614   if (nm == nullptr) return (Method*)nullptr;
 615   Metadata* m = nm->metadata_at(_method_index);
 616   assert(m != nullptr || _method_index == 0, "should be non-null for non-zero index");
 617   assert(m == nullptr || m->is_method(), "not a method");
 618   return (Method*)m;
 619 }
 620 
 621 void virtual_call_Relocation::clear_inline_cache() {
 622   ResourceMark rm;
 623   CompiledIC* icache = CompiledIC_at(this);
 624   icache->set_to_clean();
 625 }
 626 
 627 
 628 void opt_virtual_call_Relocation::pack_data_to(CodeSection* dest) {
 629   short* p = (short*) dest->locs_end();
 630   p = pack_1_int_to(p, _method_index);
 631   dest->set_locs_end((relocInfo*) p);
 632 }
 633 
 634 void opt_virtual_call_Relocation::unpack_data() {
 635   _method_index = unpack_1_int();
 636 }
 637 
 638 Method* opt_virtual_call_Relocation::method_value() {
 639   nmethod* nm = code();
 640   if (nm == nullptr) return (Method*)nullptr;
 641   Metadata* m = nm->metadata_at(_method_index);
 642   assert(m != nullptr || _method_index == 0, "should be non-null for non-zero index");
 643   assert(m == nullptr || m->is_method(), "not a method");
 644   return (Method*)m;
 645 }
 646 
 647 void opt_virtual_call_Relocation::clear_inline_cache() {
 648   ResourceMark rm;
 649   CompiledDirectCall* callsite = CompiledDirectCall::at(this);
 650   callsite->set_to_clean();
 651 }
 652 
 653 address opt_virtual_call_Relocation::static_stub() {
 654   // search for the static stub who points back to this static call
 655   address static_call_addr = addr();
 656   RelocIterator iter(code());
 657   while (iter.next()) {
 658     if (iter.type() == relocInfo::static_stub_type) {
 659       static_stub_Relocation* stub_reloc = iter.static_stub_reloc();
 660       if (stub_reloc->static_call() == static_call_addr) {
 661         return iter.addr();
 662       }
 663     }
 664   }
 665   return nullptr;
 666 }
 667 
 668 Method* static_call_Relocation::method_value() {
 669   nmethod* nm = code();
 670   if (nm == nullptr) return (Method*)nullptr;
 671   Metadata* m = nm->metadata_at(_method_index);
 672   assert(m != nullptr || _method_index == 0, "should be non-null for non-zero index");
 673   assert(m == nullptr || m->is_method(), "not a method");
 674   return (Method*)m;
 675 }
 676 
 677 void static_call_Relocation::pack_data_to(CodeSection* dest) {
 678   short* p = (short*) dest->locs_end();
 679   p = pack_1_int_to(p, _method_index);
 680   dest->set_locs_end((relocInfo*) p);
 681 }
 682 
 683 void static_call_Relocation::unpack_data() {
 684   _method_index = unpack_1_int();
 685 }
 686 
 687 void static_call_Relocation::clear_inline_cache() {
 688   ResourceMark rm;
 689   CompiledDirectCall* callsite = CompiledDirectCall::at(this);
 690   callsite->set_to_clean();
 691 }
 692 
 693 
 694 address static_call_Relocation::static_stub() {
 695   // search for the static stub who points back to this static call
 696   address static_call_addr = addr();
 697   RelocIterator iter(code());
 698   while (iter.next()) {
 699     if (iter.type() == relocInfo::static_stub_type) {
 700       static_stub_Relocation* stub_reloc = iter.static_stub_reloc();
 701       if (stub_reloc->static_call() == static_call_addr) {
 702         return iter.addr();
 703       }
 704     }
 705   }
 706   return nullptr;
 707 }
 708 
 709 // Finds the trampoline address for a call. If no trampoline stub is
 710 // found nullptr is returned which can be handled by the caller.
 711 address trampoline_stub_Relocation::get_trampoline_for(address call, nmethod* code) {
 712   // There are no relocations available when the code gets relocated
 713   // because of CodeBuffer expansion.
 714   if (code->relocation_size() == 0)
 715     return nullptr;
 716 
 717   RelocIterator iter(code, call);
 718   while (iter.next()) {
 719     if (iter.type() == relocInfo::trampoline_stub_type) {
 720       if (iter.trampoline_stub_reloc()->owner() == call) {
 721         return iter.addr();
 722       }
 723     }
 724   }
 725 
 726   return nullptr;
 727 }
 728 
 729 void static_stub_Relocation::clear_inline_cache() {
 730   // Call stub is only used when calling the interpreted code.
 731   // It does not really need to be cleared, except that we want to clean out the methodoop.
 732   CompiledDirectCall::set_stub_to_clean(this);
 733 }
 734 
 735 
 736 void external_word_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
 737   if (_target != nullptr) {
 738     // Probably this reference is absolute,  not relative, so the following is
 739     // probably a no-op.
 740     set_value(_target);
 741   }
 742   // If target is nullptr, this is  an absolute embedded reference to an external
 743   // location, which means  there is nothing to fix here.  In either case, the
 744   // resulting target should be an "external" address.
 745 #ifdef ASSERT
 746   if (SCCache::is_on()) {
 747     // SCA needs relocation info for card table base which may point to CodeCache
 748     if (is_card_table_address(target())) {
 749       return;
 750     }
 751   }
 752 #endif
 753   postcond(src->section_index_of(target()) == CodeBuffer::SECT_NONE);
 754   postcond(dest->section_index_of(target()) == CodeBuffer::SECT_NONE);
 755 }
 756 
 757 
 758 address external_word_Relocation::target() {
 759   address target = _target;
 760   if (target == nullptr) {
 761     target = pd_get_address_from_code();
 762   }
 763   return target;
 764 }
 765 
 766 
 767 void internal_word_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
 768   address target = _target;
 769   if (target == nullptr) {
 770     target = new_addr_for(this->target(), src, dest);
 771   }
 772   set_value(target);
 773 }
 774 
 775 
 776 address internal_word_Relocation::target() {
 777   address target = _target;
 778   if (target == nullptr) {
 779     if (addr_in_const()) {
 780       target = *(address*)addr();
 781     } else {
 782       target = pd_get_address_from_code();
 783     }
 784   }
 785   return target;
 786 }
 787 
 788 const char* relocInfo::type_name(relocInfo::relocType t) {
 789   switch (t) {
 790   #define EACH_CASE(name) \
 791   case relocInfo::name##_type: \
 792     return #name;
 793 
 794   APPLY_TO_RELOCATIONS(EACH_CASE);
 795   #undef EACH_CASE
 796 
 797   case relocInfo::none:
 798     return "none";
 799   case relocInfo::data_prefix_tag:
 800     return "prefix";
 801   default:
 802     return "UNKNOWN RELOC TYPE";
 803   }
 804 }
 805 
 806 
 807 void RelocIterator::print_current_on(outputStream* st) {
 808   if (!has_current()) {
 809     st->print_cr("(no relocs)");
 810     return;
 811   }
 812   st->print("relocInfo@" INTPTR_FORMAT " [type=%d(%s) addr=" INTPTR_FORMAT " offset=%d",
 813             p2i(_current), type(), relocInfo::type_name(type()), p2i(_addr), _current->addr_offset());
 814   if (current()->format() != 0)
 815     st->print(" format=%d", current()->format());
 816   if (datalen() == 1) {
 817     st->print(" data=%d", data()[0]);
 818   } else if (datalen() > 0) {
 819     st->print(" data={");
 820     for (int i = 0; i < datalen(); i++) {
 821       st->print("%04x", data()[i] & 0xFFFF);
 822     }
 823     st->print("}");
 824   }
 825   st->print("]");
 826   switch (type()) {
 827   case relocInfo::oop_type:
 828     {
 829       oop_Relocation* r = oop_reloc();
 830       oop* oop_addr  = nullptr;
 831       oop  raw_oop   = nullptr;
 832       oop  oop_value = nullptr;
 833       if (code() != nullptr || r->oop_is_immediate()) {
 834         oop_addr  = r->oop_addr();
 835         raw_oop   = *oop_addr;
 836         oop_value = r->oop_value();
 837       }
 838       st->print(" | [oop_addr=" INTPTR_FORMAT " *=" INTPTR_FORMAT " index=%d]",
 839                  p2i(oop_addr), p2i(raw_oop), r->oop_index());
 840       // Do not print the oop by default--we want this routine to
 841       // work even during GC or other inconvenient times.
 842       if (WizardMode && oop_value != nullptr) {
 843         st->print("oop_value=" INTPTR_FORMAT ": ", p2i(oop_value));
 844         if (oopDesc::is_oop(oop_value)) {
 845           oop_value->print_value_on(st);
 846         }
 847       }
 848       break;
 849     }
 850   case relocInfo::metadata_type:
 851     {
 852       metadata_Relocation* r = metadata_reloc();
 853       Metadata** metadata_addr  = nullptr;
 854       Metadata*    raw_metadata   = nullptr;
 855       Metadata*    metadata_value = nullptr;
 856       if (code() != nullptr || r->metadata_is_immediate()) {
 857         metadata_addr  = r->metadata_addr();
 858         raw_metadata   = *metadata_addr;
 859         metadata_value = r->metadata_value();
 860       }
 861       st->print(" | [metadata_addr=" INTPTR_FORMAT " *=" INTPTR_FORMAT " index=%d]",
 862                  p2i(metadata_addr), p2i(raw_metadata), r->metadata_index());
 863       if (metadata_value != nullptr) {
 864         st->print("metadata_value=" INTPTR_FORMAT ": ", p2i(metadata_value));
 865         metadata_value->print_value_on(st);
 866       }
 867       break;
 868     }
 869   case relocInfo::external_word_type:
 870   case relocInfo::internal_word_type:
 871   case relocInfo::section_word_type:
 872     {
 873       DataRelocation* r = (DataRelocation*) reloc();
 874       st->print(" | [target=" INTPTR_FORMAT "]", p2i(r->value())); //value==target
 875       break;
 876     }
 877   case relocInfo::static_call_type:
 878     {
 879       static_call_Relocation* r = (static_call_Relocation*) reloc();
 880       st->print(" | [destination=" INTPTR_FORMAT " metadata=" INTPTR_FORMAT "]",
 881                  p2i(r->destination()), p2i(r->method_value()));
 882       CodeBlob* cb = CodeCache::find_blob(r->destination());
 883       if (cb != nullptr) {
 884         st->print(" Blob::%s", cb->name());
 885       }
 886       break;
 887     }
 888   case relocInfo::runtime_call_type:
 889   case relocInfo::runtime_call_w_cp_type:
 890     {
 891       CallRelocation* r = (CallRelocation*) reloc();
 892       address dest = r->destination();
 893       st->print(" | [destination=" INTPTR_FORMAT "]", p2i(dest));
 894       if (StubRoutines::contains(dest)) {
 895         StubCodeDesc* desc = StubCodeDesc::desc_for(dest);
 896         if (desc == nullptr) {
 897           desc = StubCodeDesc::desc_for(dest + frame::pc_return_offset);
 898         }
 899         if (desc != nullptr) {
 900           st->print(" Stub::%s", desc->name());
 901         }
 902       } else {
 903         CodeBlob* cb = CodeCache::find_blob(dest);
 904         if (cb != nullptr) {
 905           st->print(" Blob::%s", cb->name());
 906         } else {
 907           ResourceMark rm;
 908           const int buflen = 1024;
 909           char* buf = NEW_RESOURCE_ARRAY(char, buflen);
 910           int offset;
 911           if (os::dll_address_to_function_name(dest, buf, buflen, &offset)) {
 912             st->print(" %s", buf);
 913             if (offset != 0) {
 914               st->print("+%d", offset);
 915             }
 916           }
 917         }
 918       }
 919       break;
 920     }
 921   case relocInfo::virtual_call_type:
 922     {
 923       virtual_call_Relocation* r = (virtual_call_Relocation*) reloc();
 924       st->print(" | [destination=" INTPTR_FORMAT " cached_value=" INTPTR_FORMAT " metadata=" INTPTR_FORMAT "]",
 925                 p2i(r->destination()), p2i(r->cached_value()), p2i(r->method_value()));
 926       CodeBlob* cb = CodeCache::find_blob(r->destination());
 927       if (cb != nullptr) {
 928         st->print(" Blob::%s", cb->name());
 929       }
 930       break;
 931     }
 932   case relocInfo::static_stub_type:
 933     {
 934       static_stub_Relocation* r = (static_stub_Relocation*) reloc();
 935       st->print(" | [static_call=" INTPTR_FORMAT "]", p2i(r->static_call()));
 936       break;
 937     }
 938   case relocInfo::trampoline_stub_type:
 939     {
 940       trampoline_stub_Relocation* r = (trampoline_stub_Relocation*) reloc();
 941       st->print(" | [trampoline owner=" INTPTR_FORMAT "]", p2i(r->owner()));
 942       break;
 943     }
 944   case relocInfo::opt_virtual_call_type:
 945     {
 946       opt_virtual_call_Relocation* r = (opt_virtual_call_Relocation*) reloc();
 947       st->print(" | [destination=" INTPTR_FORMAT " metadata=" INTPTR_FORMAT "]",
 948                  p2i(r->destination()), p2i(r->method_value()));
 949       CodeBlob* cb = CodeCache::find_blob(r->destination());
 950       if (cb != nullptr) {
 951         st->print(" Blob::%s", cb->name());
 952       }
 953       break;
 954     }
 955   default:
 956     break;
 957   }
 958   st->cr();
 959 }
 960 
 961 
 962 void RelocIterator::print_on(outputStream* st) {
 963   RelocIterator save_this = (*this);
 964   relocInfo* scan = _current;
 965   if (!has_current())  scan += 1;  // nothing to scan here!
 966 
 967   bool skip_next = has_current();
 968   bool got_next;
 969   while (true) {
 970     got_next = (skip_next || next());
 971     skip_next = false;
 972 
 973     st->print("         @" INTPTR_FORMAT ": ", p2i(scan));
 974     relocInfo* newscan = _current+1;
 975     if (!has_current())  newscan -= 1;  // nothing to scan here!
 976     while (scan < newscan) {
 977       st->print("%04x", *(short*)scan & 0xFFFF);
 978       scan++;
 979     }
 980     st->cr();
 981 
 982     if (!got_next)  break;
 983     print_current_on(st);
 984   }
 985 
 986   (*this) = save_this;
 987 }
 988 
 989 //---------------------------------------------------------------------------------
 990 // Non-product code
 991 
 992 #ifndef PRODUCT
 993 
 994 // For the debugger:
 995 extern "C"
 996 void print_blob_locs(nmethod* nm) {
 997   nm->print();
 998   RelocIterator iter(nm);
 999   iter.print_on(tty);
1000 }
1001 extern "C"
1002 void print_buf_locs(CodeBuffer* cb) {
1003   FlagSetting fs(PrintRelocations, true);
1004   cb->print_on(tty);
1005 }
1006 #endif // !PRODUCT