1 /*
   2  * Copyright (c) 1997, 2009, 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 "incls/_precompiled.incl"
  26 # include "incls/_codeBuffer.cpp.incl"
  27 
  28 // The structure of a CodeSection:
  29 //
  30 //    _start ->           +----------------+
  31 //                        | machine code...|
  32 //    _end ->             |----------------|
  33 //                        |                |
  34 //                        |    (empty)     |
  35 //                        |                |
  36 //                        |                |
  37 //                        +----------------+
  38 //    _limit ->           |                |
  39 //
  40 //    _locs_start ->      +----------------+
  41 //                        |reloc records...|
  42 //                        |----------------|
  43 //    _locs_end ->        |                |
  44 //                        |                |
  45 //                        |    (empty)     |
  46 //                        |                |
  47 //                        |                |
  48 //                        +----------------+
  49 //    _locs_limit ->      |                |
  50 // The _end (resp. _limit) pointer refers to the first
  51 // unused (resp. unallocated) byte.
  52 
  53 // The structure of the CodeBuffer while code is being accumulated:
  54 //
  55 //    _total_start ->    \
  56 //    _insts._start ->              +----------------+
  57 //                                  |                |
  58 //                                  |     Code       |
  59 //                                  |                |
  60 //    _stubs._start ->              |----------------|
  61 //                                  |                |
  62 //                                  |    Stubs       | (also handlers for deopt/exception)
  63 //                                  |                |
  64 //    _consts._start ->             |----------------|
  65 //                                  |                |
  66 //                                  |   Constants    |
  67 //                                  |                |
  68 //                                  +----------------+
  69 //    + _total_size ->              |                |
  70 //
  71 // When the code and relocations are copied to the code cache,
  72 // the empty parts of each section are removed, and everything
  73 // is copied into contiguous locations.
  74 
  75 typedef CodeBuffer::csize_t csize_t;  // file-local definition
  76 
  77 // external buffer, in a predefined CodeBlob or other buffer area
  78 // Important: The code_start must be taken exactly, and not realigned.
  79 CodeBuffer::CodeBuffer(address code_start, csize_t code_size) {
  80   assert(code_start != NULL, "sanity");
  81   initialize_misc("static buffer");
  82   initialize(code_start, code_size);
  83   assert(verify_section_allocation(), "initial use of buffer OK");
  84 }
  85 
  86 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) {
  87   // Compute maximal alignment.
  88   int align = _insts.alignment();
  89   // Always allow for empty slop around each section.
  90   int slop = (int) CodeSection::end_slop();
  91 
  92   assert(blob() == NULL, "only once");
  93   set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1)));
  94   if (blob() == NULL) {
  95     // The assembler constructor will throw a fatal on an empty CodeBuffer.
  96     return;  // caller must test this
  97   }
  98 
  99   // Set up various pointers into the blob.
 100   initialize(_total_start, _total_size);
 101 
 102   assert((uintptr_t)code_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned");
 103 
 104   pd_initialize();
 105 
 106   if (locs_size != 0) {
 107     _insts.initialize_locs(locs_size / sizeof(relocInfo));
 108   }
 109 
 110   assert(verify_section_allocation(), "initial use of blob is OK");
 111 }
 112 
 113 
 114 CodeBuffer::~CodeBuffer() {
 115   // If we allocate our code buffer from the CodeCache
 116   // via a BufferBlob, and it's not permanent, then
 117   // free the BufferBlob.
 118   // The rest of the memory will be freed when the ResourceObj
 119   // is released.
 120   assert(verify_section_allocation(), "final storage configuration still OK");
 121   for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) {
 122     // Previous incarnations of this buffer are held live, so that internal
 123     // addresses constructed before expansions will not be confused.
 124     cb->free_blob();
 125   }
 126 
 127   // free any overflow storage
 128   delete _overflow_arena;
 129 
 130 #ifdef ASSERT
 131   Copy::fill_to_bytes(this, sizeof(*this), badResourceValue);
 132 #endif
 133 }
 134 
 135 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) {
 136   assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once");
 137   DEBUG_ONLY(_default_oop_recorder.oop_size());  // force unused OR to be frozen
 138   _oop_recorder = r;
 139 }
 140 
 141 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) {
 142   assert(cs != &_insts, "insts is the memory provider, not the consumer");
 143 #ifdef ASSERT
 144   for (int n = (int)SECT_INSTS+1; n < (int)SECT_LIMIT; n++) {
 145     CodeSection* prevCS = code_section(n);
 146     if (prevCS == cs)  break;
 147     assert(!prevCS->is_allocated(), "section allocation must be in reverse order");
 148   }
 149 #endif
 150   csize_t slop = CodeSection::end_slop();  // margin between sections
 151   int align = cs->alignment();
 152   assert(is_power_of_2(align), "sanity");
 153   address start  = _insts._start;
 154   address limit  = _insts._limit;
 155   address middle = limit - size;
 156   middle -= (intptr_t)middle & (align-1);  // align the division point downward
 157   guarantee(middle - slop > start, "need enough space to divide up");
 158   _insts._limit = middle - slop;  // subtract desired space, plus slop
 159   cs->initialize(middle, limit - middle);
 160   assert(cs->start() == middle, "sanity");
 161   assert(cs->limit() == limit,  "sanity");
 162   // give it some relocations to start with, if the main section has them
 163   if (_insts.has_locs())  cs->initialize_locs(1);
 164 }
 165 
 166 void CodeBuffer::freeze_section(CodeSection* cs) {
 167   CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1);
 168   csize_t frozen_size = cs->size();
 169   if (next_cs != NULL) {
 170     frozen_size = next_cs->align_at_start(frozen_size);
 171   }
 172   address old_limit = cs->limit();
 173   address new_limit = cs->start() + frozen_size;
 174   relocInfo* old_locs_limit = cs->locs_limit();
 175   relocInfo* new_locs_limit = cs->locs_end();
 176   // Patch the limits.
 177   cs->_limit = new_limit;
 178   cs->_locs_limit = new_locs_limit;
 179   cs->_frozen = true;
 180   if (!next_cs->is_allocated() && !next_cs->is_frozen()) {
 181     // Give remaining buffer space to the following section.
 182     next_cs->initialize(new_limit, old_limit - new_limit);
 183     next_cs->initialize_shared_locs(new_locs_limit,
 184                                     old_locs_limit - new_locs_limit);
 185   }
 186 }
 187 
 188 void CodeBuffer::set_blob(BufferBlob* blob) {
 189   _blob = blob;
 190   if (blob != NULL) {
 191     address start = blob->instructions_begin();
 192     address end   = blob->instructions_end();
 193     // Round up the starting address.
 194     int align = _insts.alignment();
 195     start += (-(intptr_t)start) & (align-1);
 196     _total_start = start;
 197     _total_size  = end - start;
 198   } else {
 199     #ifdef ASSERT
 200     // Clean out dangling pointers.
 201     _total_start    = badAddress;
 202     _insts._start   = _insts._end   = badAddress;
 203     _stubs._start   = _stubs._end   = badAddress;
 204     _consts._start  = _consts._end  = badAddress;
 205     #endif //ASSERT
 206   }
 207 }
 208 
 209 void CodeBuffer::free_blob() {
 210   if (_blob != NULL) {
 211     BufferBlob::free(_blob);
 212     set_blob(NULL);
 213   }
 214 }
 215 
 216 const char* CodeBuffer::code_section_name(int n) {
 217 #ifdef PRODUCT
 218   return NULL;
 219 #else //PRODUCT
 220   switch (n) {
 221   case SECT_INSTS:             return "insts";
 222   case SECT_STUBS:             return "stubs";
 223   case SECT_CONSTS:            return "consts";
 224   default:                     return NULL;
 225   }
 226 #endif //PRODUCT
 227 }
 228 
 229 int CodeBuffer::section_index_of(address addr) const {
 230   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 231     const CodeSection* cs = code_section(n);
 232     if (cs->allocates(addr))  return n;
 233   }
 234   return SECT_NONE;
 235 }
 236 
 237 int CodeBuffer::locator(address addr) const {
 238   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 239     const CodeSection* cs = code_section(n);
 240     if (cs->allocates(addr)) {
 241       return locator(addr - cs->start(), n);
 242     }
 243   }
 244   return -1;
 245 }
 246 
 247 address CodeBuffer::locator_address(int locator) const {
 248   if (locator < 0)  return NULL;
 249   address start = code_section(locator_sect(locator))->start();
 250   return start + locator_pos(locator);
 251 }
 252 
 253 address CodeBuffer::decode_begin() {
 254   address begin = _insts.start();
 255   if (_decode_begin != NULL && _decode_begin > begin)
 256     begin = _decode_begin;
 257   return begin;
 258 }
 259 
 260 
 261 GrowableArray<int>* CodeBuffer::create_patch_overflow() {
 262   if (_overflow_arena == NULL) {
 263     _overflow_arena = new Arena();
 264   }
 265   return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0);
 266 }
 267 
 268 
 269 // Helper function for managing labels and their target addresses.
 270 // Returns a sensible address, and if it is not the label's final
 271 // address, notes the dependency (at 'branch_pc') on the label.
 272 address CodeSection::target(Label& L, address branch_pc) {
 273   if (L.is_bound()) {
 274     int loc = L.loc();
 275     if (index() == CodeBuffer::locator_sect(loc)) {
 276       return start() + CodeBuffer::locator_pos(loc);
 277     } else {
 278       return outer()->locator_address(loc);
 279     }
 280   } else {
 281     assert(allocates2(branch_pc), "sanity");
 282     address base = start();
 283     int patch_loc = CodeBuffer::locator(branch_pc - base, index());
 284     L.add_patch_at(outer(), patch_loc);
 285 
 286     // Need to return a pc, doesn't matter what it is since it will be
 287     // replaced during resolution later.
 288     // Don't return NULL or badAddress, since branches shouldn't overflow.
 289     // Don't return base either because that could overflow displacements
 290     // for shorter branches.  It will get checked when bound.
 291     return branch_pc;
 292   }
 293 }
 294 
 295 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) {
 296   Relocation* reloc = spec.reloc();
 297   relocInfo::relocType rtype = (relocInfo::relocType) reloc->type();
 298   if (rtype == relocInfo::none)  return;
 299 
 300   // The assertion below has been adjusted, to also work for
 301   // relocation for fixup.  Sometimes we want to put relocation
 302   // information for the next instruction, since it will be patched
 303   // with a call.
 304   assert(start() <= at && at <= end()+1,
 305          "cannot relocate data outside code boundaries");
 306 
 307   if (!has_locs()) {
 308     // no space for relocation information provided => code cannot be
 309     // relocated.  Make sure that relocate is only called with rtypes
 310     // that can be ignored for this kind of code.
 311     assert(rtype == relocInfo::none              ||
 312            rtype == relocInfo::runtime_call_type ||
 313            rtype == relocInfo::internal_word_type||
 314            rtype == relocInfo::section_word_type ||
 315            rtype == relocInfo::external_word_type,
 316            "code needs relocation information");
 317     // leave behind an indication that we attempted a relocation
 318     DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress);
 319     return;
 320   }
 321 
 322   // Advance the point, noting the offset we'll have to record.
 323   csize_t offset = at - locs_point();
 324   set_locs_point(at);
 325 
 326   // Test for a couple of overflow conditions; maybe expand the buffer.
 327   relocInfo* end = locs_end();
 328   relocInfo* req = end + relocInfo::length_limit;
 329   // Check for (potential) overflow
 330   if (req >= locs_limit() || offset >= relocInfo::offset_limit()) {
 331     req += (uint)offset / (uint)relocInfo::offset_limit();
 332     if (req >= locs_limit()) {
 333       // Allocate or reallocate.
 334       expand_locs(locs_count() + (req - end));
 335       // reload pointer
 336       end = locs_end();
 337     }
 338   }
 339 
 340   // If the offset is giant, emit filler relocs, of type 'none', but
 341   // each carrying the largest possible offset, to advance the locs_point.
 342   while (offset >= relocInfo::offset_limit()) {
 343     assert(end < locs_limit(), "adjust previous paragraph of code");
 344     *end++ = filler_relocInfo();
 345     offset -= filler_relocInfo().addr_offset();
 346   }
 347 
 348   // If it's a simple reloc with no data, we'll just write (rtype | offset).
 349   (*end) = relocInfo(rtype, offset, format);
 350 
 351   // If it has data, insert the prefix, as (data_prefix_tag | data1), data2.
 352   end->initialize(this, reloc);
 353 }
 354 
 355 void CodeSection::initialize_locs(int locs_capacity) {
 356   assert(_locs_start == NULL, "only one locs init step, please");
 357   // Apply a priori lower limits to relocation size:
 358   csize_t min_locs = MAX2(size() / 16, (csize_t)4);
 359   if (locs_capacity < min_locs)  locs_capacity = min_locs;
 360   relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity);
 361   _locs_start    = locs_start;
 362   _locs_end      = locs_start;
 363   _locs_limit    = locs_start + locs_capacity;
 364   _locs_own      = true;
 365 }
 366 
 367 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) {
 368   assert(_locs_start == NULL, "do this before locs are allocated");
 369   // Internal invariant:  locs buf must be fully aligned.
 370   // See copy_relocations_to() below.
 371   while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) {
 372     ++buf; --length;
 373   }
 374   if (length > 0) {
 375     _locs_start = buf;
 376     _locs_end   = buf;
 377     _locs_limit = buf + length;
 378     _locs_own   = false;
 379   }
 380 }
 381 
 382 void CodeSection::initialize_locs_from(const CodeSection* source_cs) {
 383   int lcount = source_cs->locs_count();
 384   if (lcount != 0) {
 385     initialize_shared_locs(source_cs->locs_start(), lcount);
 386     _locs_end = _locs_limit = _locs_start + lcount;
 387     assert(is_allocated(), "must have copied code already");
 388     set_locs_point(start() + source_cs->locs_point_off());
 389   }
 390   assert(this->locs_count() == source_cs->locs_count(), "sanity");
 391 }
 392 
 393 void CodeSection::expand_locs(int new_capacity) {
 394   if (_locs_start == NULL) {
 395     initialize_locs(new_capacity);
 396     return;
 397   } else {
 398     int old_count    = locs_count();
 399     int old_capacity = locs_capacity();
 400     if (new_capacity < old_capacity * 2)
 401       new_capacity = old_capacity * 2;
 402     relocInfo* locs_start;
 403     if (_locs_own) {
 404       locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity);
 405     } else {
 406       locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity);
 407       Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo));
 408       _locs_own = true;
 409     }
 410     _locs_start    = locs_start;
 411     _locs_end      = locs_start + old_count;
 412     _locs_limit    = locs_start + new_capacity;
 413   }
 414 }
 415 
 416 
 417 /// Support for emitting the code to its final location.
 418 /// The pattern is the same for all functions.
 419 /// We iterate over all the sections, padding each to alignment.
 420 
 421 csize_t CodeBuffer::total_code_size() const {
 422   csize_t code_size_so_far = 0;
 423   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 424     const CodeSection* cs = code_section(n);
 425     if (cs->is_empty())  continue;  // skip trivial section
 426     code_size_so_far = cs->align_at_start(code_size_so_far);
 427     code_size_so_far += cs->size();
 428   }
 429   return code_size_so_far;
 430 }
 431 
 432 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const {
 433   address buf = dest->_total_start;
 434   csize_t buf_offset = 0;
 435   assert(dest->_total_size >= total_code_size(), "must be big enough");
 436 
 437   {
 438     // not sure why this is here, but why not...
 439     int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment);
 440     assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment");
 441   }
 442 
 443   const CodeSection* prev_cs      = NULL;
 444   CodeSection*       prev_dest_cs = NULL;
 445   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 446     // figure compact layout of each section
 447     const CodeSection* cs = code_section(n);
 448     address cstart = cs->start();
 449     address cend   = cs->end();
 450     csize_t csize  = cend - cstart;
 451 
 452     CodeSection* dest_cs = dest->code_section(n);
 453     if (!cs->is_empty()) {
 454       // Compute initial padding; assign it to the previous non-empty guy.
 455       // Cf. figure_expanded_capacities.
 456       csize_t padding = cs->align_at_start(buf_offset) - buf_offset;
 457       if (padding != 0) {
 458         buf_offset += padding;
 459         assert(prev_dest_cs != NULL, "sanity");
 460         prev_dest_cs->_limit += padding;
 461       }
 462       #ifdef ASSERT
 463       if (prev_cs != NULL && prev_cs->is_frozen() && n < SECT_CONSTS) {
 464         // Make sure the ends still match up.
 465         // This is important because a branch in a frozen section
 466         // might target code in a following section, via a Label,
 467         // and without a relocation record.  See Label::patch_instructions.
 468         address dest_start = buf+buf_offset;
 469         csize_t start2start = cs->start() - prev_cs->start();
 470         csize_t dest_start2start = dest_start - prev_dest_cs->start();
 471         assert(start2start == dest_start2start, "cannot stretch frozen sect");
 472       }
 473       #endif //ASSERT
 474       prev_dest_cs = dest_cs;
 475       prev_cs      = cs;
 476     }
 477 
 478     debug_only(dest_cs->_start = NULL);  // defeat double-initialization assert
 479     dest_cs->initialize(buf+buf_offset, csize);
 480     dest_cs->set_end(buf+buf_offset+csize);
 481     assert(dest_cs->is_allocated(), "must always be allocated");
 482     assert(cs->is_empty() == dest_cs->is_empty(), "sanity");
 483 
 484     buf_offset += csize;
 485   }
 486 
 487   // Done calculating sections; did it come out to the right end?
 488   assert(buf_offset == total_code_size(), "sanity");
 489   assert(dest->verify_section_allocation(), "final configuration works");
 490 }
 491 
 492 csize_t CodeBuffer::total_offset_of(address addr) const {
 493   csize_t code_size_so_far = 0;
 494   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 495     const CodeSection* cs = code_section(n);
 496     if (!cs->is_empty()) {
 497       code_size_so_far = cs->align_at_start(code_size_so_far);
 498     }
 499     if (cs->contains2(addr)) {
 500       return code_size_so_far + (addr - cs->start());
 501     }
 502     code_size_so_far += cs->size();
 503   }
 504 #ifndef PRODUCT
 505   tty->print_cr("Dangling address " PTR_FORMAT " in:", addr);
 506   ((CodeBuffer*)this)->print();
 507 #endif
 508   ShouldNotReachHere();
 509   return -1;
 510 }
 511 
 512 csize_t CodeBuffer::total_relocation_size() const {
 513   csize_t lsize = copy_relocations_to(NULL);  // dry run only
 514   csize_t csize = total_code_size();
 515   csize_t total = RelocIterator::locs_and_index_size(csize, lsize);
 516   return (csize_t) align_size_up(total, HeapWordSize);
 517 }
 518 
 519 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const {
 520   address buf = NULL;
 521   csize_t buf_offset = 0;
 522   csize_t buf_limit = 0;
 523   if (dest != NULL) {
 524     buf = (address)dest->relocation_begin();
 525     buf_limit = (address)dest->relocation_end() - buf;
 526     assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned");
 527     assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized");
 528   }
 529   // if dest == NULL, this is just the sizing pass
 530 
 531   csize_t code_end_so_far = 0;
 532   csize_t code_point_so_far = 0;
 533   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 534     // pull relocs out of each section
 535     const CodeSection* cs = code_section(n);
 536     assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity");
 537     if (cs->is_empty())  continue;  // skip trivial section
 538     relocInfo* lstart = cs->locs_start();
 539     relocInfo* lend   = cs->locs_end();
 540     csize_t    lsize  = (csize_t)( (address)lend - (address)lstart );
 541     csize_t    csize  = cs->size();
 542     code_end_so_far = cs->align_at_start(code_end_so_far);
 543 
 544     if (lsize > 0) {
 545       // Figure out how to advance the combined relocation point
 546       // first to the beginning of this section.
 547       // We'll insert one or more filler relocs to span that gap.
 548       // (Don't bother to improve this by editing the first reloc's offset.)
 549       csize_t new_code_point = code_end_so_far;
 550       for (csize_t jump;
 551            code_point_so_far < new_code_point;
 552            code_point_so_far += jump) {
 553         jump = new_code_point - code_point_so_far;
 554         relocInfo filler = filler_relocInfo();
 555         if (jump >= filler.addr_offset()) {
 556           jump = filler.addr_offset();
 557         } else {  // else shrink the filler to fit
 558           filler = relocInfo(relocInfo::none, jump);
 559         }
 560         if (buf != NULL) {
 561           assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds");
 562           *(relocInfo*)(buf+buf_offset) = filler;
 563         }
 564         buf_offset += sizeof(filler);
 565       }
 566 
 567       // Update code point and end to skip past this section:
 568       csize_t last_code_point = code_end_so_far + cs->locs_point_off();
 569       assert(code_point_so_far <= last_code_point, "sanity");
 570       code_point_so_far = last_code_point; // advance past this guy's relocs
 571     }
 572     code_end_so_far += csize;  // advance past this guy's instructions too
 573 
 574     // Done with filler; emit the real relocations:
 575     if (buf != NULL && lsize != 0) {
 576       assert(buf_offset + lsize <= buf_limit, "target in bounds");
 577       assert((uintptr_t)lstart % HeapWordSize == 0, "sane start");
 578       if (buf_offset % HeapWordSize == 0) {
 579         // Use wordwise copies if possible:
 580         Copy::disjoint_words((HeapWord*)lstart,
 581                              (HeapWord*)(buf+buf_offset),
 582                              (lsize + HeapWordSize-1) / HeapWordSize);
 583       } else {
 584         Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize);
 585       }
 586     }
 587     buf_offset += lsize;
 588   }
 589 
 590   // Align end of relocation info in target.
 591   while (buf_offset % HeapWordSize != 0) {
 592     if (buf != NULL) {
 593       relocInfo padding = relocInfo(relocInfo::none, 0);
 594       assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds");
 595       *(relocInfo*)(buf+buf_offset) = padding;
 596     }
 597     buf_offset += sizeof(relocInfo);
 598   }
 599 
 600   assert(code_end_so_far == total_code_size(), "sanity");
 601 
 602   // Account for index:
 603   if (buf != NULL) {
 604     RelocIterator::create_index(dest->relocation_begin(),
 605                                 buf_offset / sizeof(relocInfo),
 606                                 dest->relocation_end());
 607   }
 608 
 609   return buf_offset;
 610 }
 611 
 612 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) {
 613 #ifndef PRODUCT
 614   if (PrintNMethods && (WizardMode || Verbose)) {
 615     tty->print("done with CodeBuffer:");
 616     ((CodeBuffer*)this)->print();
 617   }
 618 #endif //PRODUCT
 619 
 620   CodeBuffer dest(dest_blob->instructions_begin(),
 621                   dest_blob->instructions_size());
 622   assert(dest_blob->instructions_size() >= total_code_size(), "good sizing");
 623   this->compute_final_layout(&dest);
 624   relocate_code_to(&dest);
 625 
 626   // transfer comments from buffer to blob
 627   dest_blob->set_comments(_comments);
 628 
 629   // Done moving code bytes; were they the right size?
 630   assert(round_to(dest.total_code_size(), oopSize) == dest_blob->instructions_size(), "sanity");
 631 
 632   // Flush generated code
 633   ICache::invalidate_range(dest_blob->instructions_begin(),
 634                            dest_blob->instructions_size());
 635 }
 636 
 637 // Move all my code into another code buffer.
 638 // Consult applicable relocs to repair embedded addresses.
 639 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const {
 640   DEBUG_ONLY(address dest_end = dest->_total_start + dest->_total_size);
 641   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 642     // pull code out of each section
 643     const CodeSection* cs = code_section(n);
 644     if (cs->is_empty())  continue;  // skip trivial section
 645     CodeSection* dest_cs = dest->code_section(n);
 646     assert(cs->size() == dest_cs->size(), "sanity");
 647     csize_t usize = dest_cs->size();
 648     csize_t wsize = align_size_up(usize, HeapWordSize);
 649     assert(dest_cs->start() + wsize <= dest_end, "no overflow");
 650     // Copy the code as aligned machine words.
 651     // This may also include an uninitialized partial word at the end.
 652     Copy::disjoint_words((HeapWord*)cs->start(),
 653                          (HeapWord*)dest_cs->start(),
 654                          wsize / HeapWordSize);
 655 
 656     if (dest->blob() == NULL) {
 657       // Destination is a final resting place, not just another buffer.
 658       // Normalize uninitialized bytes in the final padding.
 659       Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(),
 660                           Assembler::code_fill_byte());
 661     }
 662 
 663     assert(cs->locs_start() != (relocInfo*)badAddress,
 664            "this section carries no reloc storage, but reloc was attempted");
 665 
 666     // Make the new code copy use the old copy's relocations:
 667     dest_cs->initialize_locs_from(cs);
 668 
 669     { // Repair the pc relative information in the code after the move
 670       RelocIterator iter(dest_cs);
 671       while (iter.next()) {
 672         iter.reloc()->fix_relocation_after_move(this, dest);
 673       }
 674     }
 675   }
 676 }
 677 
 678 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs,
 679                                                csize_t amount,
 680                                                csize_t* new_capacity) {
 681   csize_t new_total_cap = 0;
 682 
 683   int prev_n = -1;
 684   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 685     const CodeSection* sect = code_section(n);
 686 
 687     if (!sect->is_empty()) {
 688       // Compute initial padding; assign it to the previous non-empty guy.
 689       // Cf. compute_final_layout.
 690       csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap;
 691       if (padding != 0) {
 692         new_total_cap += padding;
 693         assert(prev_n >= 0, "sanity");
 694         new_capacity[prev_n] += padding;
 695       }
 696       prev_n = n;
 697     }
 698 
 699     csize_t exp = sect->size();  // 100% increase
 700     if ((uint)exp < 4*K)  exp = 4*K;       // minimum initial increase
 701     if (sect == which_cs) {
 702       if (exp < amount)  exp = amount;
 703       if (StressCodeBuffers)  exp = amount;  // expand only slightly
 704     } else if (n == SECT_INSTS) {
 705       // scale down inst increases to a more modest 25%
 706       exp = 4*K + ((exp - 4*K) >> 2);
 707       if (StressCodeBuffers)  exp = amount / 2;  // expand only slightly
 708     } else if (sect->is_empty()) {
 709       // do not grow an empty secondary section
 710       exp = 0;
 711     }
 712     // Allow for inter-section slop:
 713     exp += CodeSection::end_slop();
 714     csize_t new_cap = sect->size() + exp;
 715     if (new_cap < sect->capacity()) {
 716       // No need to expand after all.
 717       new_cap = sect->capacity();
 718     }
 719     new_capacity[n] = new_cap;
 720     new_total_cap += new_cap;
 721   }
 722 
 723   return new_total_cap;
 724 }
 725 
 726 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) {
 727 #ifndef PRODUCT
 728   if (PrintNMethods && (WizardMode || Verbose)) {
 729     tty->print("expanding CodeBuffer:");
 730     this->print();
 731   }
 732 
 733   if (StressCodeBuffers && blob() != NULL) {
 734     static int expand_count = 0;
 735     if (expand_count >= 0)  expand_count += 1;
 736     if (expand_count > 100 && is_power_of_2(expand_count)) {
 737       tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count);
 738       // simulate an occasional allocation failure:
 739       free_blob();
 740     }
 741   }
 742 #endif //PRODUCT
 743 
 744   // Resizing must be allowed
 745   {
 746     if (blob() == NULL)  return;  // caller must check for blob == NULL
 747     for (int n = 0; n < (int)SECT_LIMIT; n++) {
 748       guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen");
 749     }
 750   }
 751 
 752   // Figure new capacity for each section.
 753   csize_t new_capacity[SECT_LIMIT];
 754   csize_t new_total_cap
 755     = figure_expanded_capacities(which_cs, amount, new_capacity);
 756 
 757   // Create a new (temporary) code buffer to hold all the new data
 758   CodeBuffer cb(name(), new_total_cap, 0);
 759   if (cb.blob() == NULL) {
 760     // Failed to allocate in code cache.
 761     free_blob();
 762     return;
 763   }
 764 
 765   // Create an old code buffer to remember which addresses used to go where.
 766   // This will be useful when we do final assembly into the code cache,
 767   // because we will need to know how to warp any internal address that
 768   // has been created at any time in this CodeBuffer's past.
 769   CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size);
 770   bxp->take_over_code_from(this);  // remember the old undersized blob
 771   DEBUG_ONLY(this->_blob = NULL);  // silence a later assert
 772   bxp->_before_expand = this->_before_expand;
 773   this->_before_expand = bxp;
 774 
 775   // Give each section its required (expanded) capacity.
 776   for (int n = (int)SECT_LIMIT-1; n >= SECT_INSTS; n--) {
 777     CodeSection* cb_sect   = cb.code_section(n);
 778     CodeSection* this_sect = code_section(n);
 779     if (new_capacity[n] == 0)  continue;  // already nulled out
 780     if (n > SECT_INSTS) {
 781       cb.initialize_section_size(cb_sect, new_capacity[n]);
 782     }
 783     assert(cb_sect->capacity() >= new_capacity[n], "big enough");
 784     address cb_start = cb_sect->start();
 785     cb_sect->set_end(cb_start + this_sect->size());
 786     if (this_sect->mark() == NULL) {
 787       cb_sect->clear_mark();
 788     } else {
 789       cb_sect->set_mark(cb_start + this_sect->mark_off());
 790     }
 791   }
 792 
 793   // Move all the code and relocations to the new blob:
 794   relocate_code_to(&cb);
 795 
 796   // Copy the temporary code buffer into the current code buffer.
 797   // Basically, do {*this = cb}, except for some control information.
 798   this->take_over_code_from(&cb);
 799   cb.set_blob(NULL);
 800 
 801   // Zap the old code buffer contents, to avoid mistakenly using them.
 802   debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size,
 803                                  badCodeHeapFreeVal));
 804 
 805   _decode_begin = NULL;  // sanity
 806 
 807   // Make certain that the new sections are all snugly inside the new blob.
 808   assert(verify_section_allocation(), "expanded allocation is ship-shape");
 809 
 810 #ifndef PRODUCT
 811   if (PrintNMethods && (WizardMode || Verbose)) {
 812     tty->print("expanded CodeBuffer:");
 813     this->print();
 814   }
 815 #endif //PRODUCT
 816 }
 817 
 818 void CodeBuffer::take_over_code_from(CodeBuffer* cb) {
 819   // Must already have disposed of the old blob somehow.
 820   assert(blob() == NULL, "must be empty");
 821 #ifdef ASSERT
 822 
 823 #endif
 824   // Take the new blob away from cb.
 825   set_blob(cb->blob());
 826   // Take over all the section pointers.
 827   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 828     CodeSection* cb_sect   = cb->code_section(n);
 829     CodeSection* this_sect = code_section(n);
 830     this_sect->take_over_code_from(cb_sect);
 831   }
 832   _overflow_arena = cb->_overflow_arena;
 833   // Make sure the old cb won't try to use it or free it.
 834   DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress);
 835 }
 836 
 837 #ifdef ASSERT
 838 bool CodeBuffer::verify_section_allocation() {
 839   address tstart = _total_start;
 840   if (tstart == badAddress)  return true;  // smashed by set_blob(NULL)
 841   address tend   = tstart + _total_size;
 842   if (_blob != NULL) {
 843     assert(tstart >= _blob->instructions_begin(), "sanity");
 844     assert(tend   <= _blob->instructions_end(),   "sanity");
 845   }
 846   address tcheck = tstart;  // advancing pointer to verify disjointness
 847   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 848     CodeSection* sect = code_section(n);
 849     if (!sect->is_allocated())  continue;
 850     assert(sect->start() >= tcheck, "sanity");
 851     tcheck = sect->start();
 852     assert((intptr_t)tcheck % sect->alignment() == 0
 853            || sect->is_empty() || _blob == NULL,
 854            "start is aligned");
 855     assert(sect->end()   >= tcheck, "sanity");
 856     assert(sect->end()   <= tend,   "sanity");
 857   }
 858   return true;
 859 }
 860 #endif //ASSERT
 861 
 862 #ifndef PRODUCT
 863 
 864 void CodeSection::dump() {
 865   address ptr = start();
 866   for (csize_t step; ptr < end(); ptr += step) {
 867     step = end() - ptr;
 868     if (step > jintSize * 4)  step = jintSize * 4;
 869     tty->print(PTR_FORMAT ": ", ptr);
 870     while (step > 0) {
 871       tty->print(" " PTR32_FORMAT, *(jint*)ptr);
 872       ptr += jintSize;
 873     }
 874     tty->cr();
 875   }
 876 }
 877 
 878 
 879 void CodeSection::decode() {
 880   Disassembler::decode(start(), end());
 881 }
 882 
 883 
 884 void CodeBuffer::block_comment(intptr_t offset, const char * comment) {
 885   _comments.add_comment(offset, comment);
 886 }
 887 
 888 
 889 class CodeComment: public CHeapObj {
 890  private:
 891   friend class CodeComments;
 892   intptr_t     _offset;
 893   const char * _comment;
 894   CodeComment* _next;
 895 
 896   ~CodeComment() {
 897     assert(_next == NULL, "wrong interface for freeing list");
 898     os::free((void*)_comment);
 899   }
 900 
 901  public:
 902   CodeComment(intptr_t offset, const char * comment) {
 903     _offset = offset;
 904     _comment = os::strdup(comment);
 905     _next = NULL;
 906   }
 907 
 908   intptr_t     offset()  const { return _offset;  }
 909   const char * comment() const { return _comment; }
 910   CodeComment* next()          { return _next; }
 911 
 912   void set_next(CodeComment* next) { _next = next; }
 913 
 914   CodeComment* find(intptr_t offset) {
 915     CodeComment* a = this;
 916     while (a != NULL && a->_offset != offset) {
 917       a = a->_next;
 918     }
 919     return a;
 920   }
 921 };
 922 
 923 
 924 void CodeComments::add_comment(intptr_t offset, const char * comment) {
 925   CodeComment* c = new CodeComment(offset, comment);
 926   CodeComment* insert = NULL;
 927   if (_comments != NULL) {
 928     CodeComment* c = _comments->find(offset);
 929     insert = c;
 930     while (c && c->offset() == offset) {
 931       insert = c;
 932       c = c->next();
 933     }
 934   }
 935   if (insert) {
 936     // insert after comments with same offset
 937     c->set_next(insert->next());
 938     insert->set_next(c);
 939   } else {
 940     c->set_next(_comments);
 941     _comments = c;
 942   }
 943 }
 944 
 945 
 946 void CodeComments::assign(CodeComments& other) {
 947   assert(_comments == NULL, "don't overwrite old value");
 948   _comments = other._comments;
 949 }
 950 
 951 
 952 void CodeComments::print_block_comment(outputStream* stream, intptr_t offset) {
 953   if (_comments != NULL) {
 954     CodeComment* c = _comments->find(offset);
 955     while (c && c->offset() == offset) {
 956       stream->bol();
 957       stream->print("  ;; ");
 958       stream->print_cr(c->comment());
 959       c = c->next();
 960     }
 961   }
 962 }
 963 
 964 
 965 void CodeComments::free() {
 966   CodeComment* n = _comments;
 967   while (n) {
 968     // unlink the node from the list saving a pointer to the next
 969     CodeComment* p = n->_next;
 970     n->_next = NULL;
 971     delete n;
 972     n = p;
 973   }
 974   _comments = NULL;
 975 }
 976 
 977 
 978 
 979 void CodeBuffer::decode() {
 980   Disassembler::decode(decode_begin(), code_end());
 981   _decode_begin = code_end();
 982 }
 983 
 984 
 985 void CodeBuffer::skip_decode() {
 986   _decode_begin = code_end();
 987 }
 988 
 989 
 990 void CodeBuffer::decode_all() {
 991   for (int n = 0; n < (int)SECT_LIMIT; n++) {
 992     // dump contents of each section
 993     CodeSection* cs = code_section(n);
 994     tty->print_cr("! %s:", code_section_name(n));
 995     if (cs != consts())
 996       cs->decode();
 997     else
 998       cs->dump();
 999   }
1000 }
1001 
1002 
1003 void CodeSection::print(const char* name) {
1004   csize_t locs_size = locs_end() - locs_start();
1005   tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s",
1006                 name, start(), end(), limit(), size(), capacity(),
1007                 is_frozen()? " [frozen]": "");
1008   tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d",
1009                 name, locs_start(), locs_end(), locs_limit(), locs_size, locs_capacity(), locs_point_off());
1010   if (PrintRelocations) {
1011     RelocIterator iter(this);
1012     iter.print();
1013   }
1014 }
1015 
1016 void CodeBuffer::print() {
1017   if (this == NULL) {
1018     tty->print_cr("NULL CodeBuffer pointer");
1019     return;
1020   }
1021 
1022   tty->print_cr("CodeBuffer:");
1023   for (int n = 0; n < (int)SECT_LIMIT; n++) {
1024     // print each section
1025     CodeSection* cs = code_section(n);
1026     cs->print(code_section_name(n));
1027   }
1028 }
1029 
1030 #endif // PRODUCT