1 /* 2 * Copyright (c) 1997, 2014, 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 "asm/codeBuffer.hpp" 27 #include "compiler/disassembler.hpp" 28 #include "memory/gcLocker.hpp" 29 #include "oops/methodData.hpp" 30 #include "oops/oop.inline.hpp" 31 #include "utilities/copy.hpp" 32 #include "utilities/xmlstream.hpp" 33 34 // The structure of a CodeSection: 35 // 36 // _start -> +----------------+ 37 // | machine code...| 38 // _end -> |----------------| 39 // | | 40 // | (empty) | 41 // | | 42 // | | 43 // +----------------+ 44 // _limit -> | | 45 // 46 // _locs_start -> +----------------+ 47 // |reloc records...| 48 // |----------------| 49 // _locs_end -> | | 50 // | | 51 // | (empty) | 52 // | | 53 // | | 54 // +----------------+ 55 // _locs_limit -> | | 56 // The _end (resp. _limit) pointer refers to the first 57 // unused (resp. unallocated) byte. 58 59 // The structure of the CodeBuffer while code is being accumulated: 60 // 61 // _total_start -> \ 62 // _insts._start -> +----------------+ 63 // | | 64 // | Code | 65 // | | 66 // _stubs._start -> |----------------| 67 // | | 68 // | Stubs | (also handlers for deopt/exception) 69 // | | 70 // _consts._start -> |----------------| 71 // | | 72 // | Constants | 73 // | | 74 // +----------------+ 75 // + _total_size -> | | 76 // 77 // When the code and relocations are copied to the code cache, 78 // the empty parts of each section are removed, and everything 79 // is copied into contiguous locations. 80 81 typedef CodeBuffer::csize_t csize_t; // file-local definition 82 83 // External buffer, in a predefined CodeBlob. 84 // Important: The code_start must be taken exactly, and not realigned. 85 CodeBuffer::CodeBuffer(CodeBlob* blob) { 86 initialize_misc("static buffer"); 87 initialize(blob->content_begin(), blob->content_size()); 88 verify_section_allocation(); 89 } 90 91 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) { 92 // Compute maximal alignment. 93 int align = _insts.alignment(); 94 // Always allow for empty slop around each section. 95 int slop = (int) CodeSection::end_slop(); 96 97 assert(blob() == NULL, "only once"); 98 set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1))); 99 if (blob() == NULL) { 100 // The assembler constructor will throw a fatal on an empty CodeBuffer. 101 return; // caller must test this 102 } 103 104 // Set up various pointers into the blob. 105 initialize(_total_start, _total_size); 106 107 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned"); 108 109 pd_initialize(); 110 111 if (locs_size != 0) { 112 _insts.initialize_locs(locs_size / sizeof(relocInfo)); 113 } 114 115 verify_section_allocation(); 116 } 117 118 119 CodeBuffer::~CodeBuffer() { 120 verify_section_allocation(); 121 122 // If we allocate our code buffer from the CodeCache 123 // via a BufferBlob, and it's not permanent, then 124 // free the BufferBlob. 125 // The rest of the memory will be freed when the ResourceObj 126 // is released. 127 for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) { 128 // Previous incarnations of this buffer are held live, so that internal 129 // addresses constructed before expansions will not be confused. 130 cb->free_blob(); 131 } 132 133 // free any overflow storage 134 delete _overflow_arena; 135 136 // Claim is that stack allocation ensures resources are cleaned up. 137 // This is resource clean up, let's hope that all were properly copied out. 138 free_strings(); 139 140 #ifdef ASSERT 141 // Save allocation type to execute assert in ~ResourceObj() 142 // which is called after this destructor. 143 assert(_default_oop_recorder.allocated_on_stack(), "should be embedded object"); 144 ResourceObj::allocation_type at = _default_oop_recorder.get_allocation_type(); 145 Copy::fill_to_bytes(this, sizeof(*this), badResourceValue); 146 ResourceObj::set_allocation_type((address)(&_default_oop_recorder), at); 147 #endif 148 } 149 150 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) { 151 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once"); 152 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen 153 _oop_recorder = r; 154 } 155 156 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) { 157 assert(cs != &_insts, "insts is the memory provider, not the consumer"); 158 csize_t slop = CodeSection::end_slop(); // margin between sections 159 int align = cs->alignment(); 160 assert(is_power_of_2(align), "sanity"); 161 address start = _insts._start; 162 address limit = _insts._limit; 163 address middle = limit - size; 164 middle -= (intptr_t)middle & (align-1); // align the division point downward 165 guarantee(middle - slop > start, "need enough space to divide up"); 166 _insts._limit = middle - slop; // subtract desired space, plus slop 167 cs->initialize(middle, limit - middle); 168 assert(cs->start() == middle, "sanity"); 169 assert(cs->limit() == limit, "sanity"); 170 // give it some relocations to start with, if the main section has them 171 if (_insts.has_locs()) cs->initialize_locs(1); 172 } 173 174 void CodeBuffer::freeze_section(CodeSection* cs) { 175 CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1); 176 csize_t frozen_size = cs->size(); 177 if (next_cs != NULL) { 178 frozen_size = next_cs->align_at_start(frozen_size); 179 } 180 address old_limit = cs->limit(); 181 address new_limit = cs->start() + frozen_size; 182 relocInfo* old_locs_limit = cs->locs_limit(); 183 relocInfo* new_locs_limit = cs->locs_end(); 184 // Patch the limits. 185 cs->_limit = new_limit; 186 cs->_locs_limit = new_locs_limit; 187 cs->_frozen = true; 188 if (!next_cs->is_allocated() && !next_cs->is_frozen()) { 189 // Give remaining buffer space to the following section. 190 next_cs->initialize(new_limit, old_limit - new_limit); 191 next_cs->initialize_shared_locs(new_locs_limit, 192 old_locs_limit - new_locs_limit); 193 } 194 } 195 196 void CodeBuffer::set_blob(BufferBlob* blob) { 197 _blob = blob; 198 if (blob != NULL) { 199 address start = blob->content_begin(); 200 address end = blob->content_end(); 201 // Round up the starting address. 202 int align = _insts.alignment(); 203 start += (-(intptr_t)start) & (align-1); 204 _total_start = start; 205 _total_size = end - start; 206 } else { 207 #ifdef ASSERT 208 // Clean out dangling pointers. 209 _total_start = badAddress; 210 _consts._start = _consts._end = badAddress; 211 _insts._start = _insts._end = badAddress; 212 _stubs._start = _stubs._end = badAddress; 213 #endif //ASSERT 214 } 215 } 216 217 void CodeBuffer::free_blob() { 218 if (_blob != NULL) { 219 BufferBlob::free(_blob); 220 set_blob(NULL); 221 } 222 } 223 224 const char* CodeBuffer::code_section_name(int n) { 225 #ifdef PRODUCT 226 return NULL; 227 #else //PRODUCT 228 switch (n) { 229 case SECT_CONSTS: return "consts"; 230 case SECT_INSTS: return "insts"; 231 case SECT_STUBS: return "stubs"; 232 default: return NULL; 233 } 234 #endif //PRODUCT 235 } 236 237 int CodeBuffer::section_index_of(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)) return n; 241 } 242 return SECT_NONE; 243 } 244 245 int CodeBuffer::locator(address addr) const { 246 for (int n = 0; n < (int)SECT_LIMIT; n++) { 247 const CodeSection* cs = code_section(n); 248 if (cs->allocates(addr)) { 249 return locator(addr - cs->start(), n); 250 } 251 } 252 return -1; 253 } 254 255 address CodeBuffer::locator_address(int locator) const { 256 if (locator < 0) return NULL; 257 address start = code_section(locator_sect(locator))->start(); 258 return start + locator_pos(locator); 259 } 260 261 bool CodeBuffer::is_backward_branch(Label& L) { 262 return L.is_bound() && insts_end() <= locator_address(L.loc()); 263 } 264 265 address CodeBuffer::decode_begin() { 266 address begin = _insts.start(); 267 if (_decode_begin != NULL && _decode_begin > begin) 268 begin = _decode_begin; 269 return begin; 270 } 271 272 273 GrowableArray<int>* CodeBuffer::create_patch_overflow() { 274 if (_overflow_arena == NULL) { 275 _overflow_arena = new (mtCode) Arena(mtCode); 276 } 277 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0); 278 } 279 280 281 // Helper function for managing labels and their target addresses. 282 // Returns a sensible address, and if it is not the label's final 283 // address, notes the dependency (at 'branch_pc') on the label. 284 address CodeSection::target(Label& L, address branch_pc) { 285 if (L.is_bound()) { 286 int loc = L.loc(); 287 if (index() == CodeBuffer::locator_sect(loc)) { 288 return start() + CodeBuffer::locator_pos(loc); 289 } else { 290 return outer()->locator_address(loc); 291 } 292 } else { 293 assert(allocates2(branch_pc), "sanity"); 294 address base = start(); 295 int patch_loc = CodeBuffer::locator(branch_pc - base, index()); 296 L.add_patch_at(outer(), patch_loc); 297 298 // Need to return a pc, doesn't matter what it is since it will be 299 // replaced during resolution later. 300 // Don't return NULL or badAddress, since branches shouldn't overflow. 301 // Don't return base either because that could overflow displacements 302 // for shorter branches. It will get checked when bound. 303 return branch_pc; 304 } 305 } 306 307 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) { 308 Relocation* reloc = spec.reloc(); 309 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type(); 310 if (rtype == relocInfo::none) return; 311 312 // The assertion below has been adjusted, to also work for 313 // relocation for fixup. Sometimes we want to put relocation 314 // information for the next instruction, since it will be patched 315 // with a call. 316 assert(start() <= at && at <= end()+1, 317 "cannot relocate data outside code boundaries"); 318 319 if (!has_locs()) { 320 // no space for relocation information provided => code cannot be 321 // relocated. Make sure that relocate is only called with rtypes 322 // that can be ignored for this kind of code. 323 assert(rtype == relocInfo::none || 324 rtype == relocInfo::runtime_call_type || 325 rtype == relocInfo::internal_word_type|| 326 rtype == relocInfo::section_word_type || 327 rtype == relocInfo::external_word_type, 328 "code needs relocation information"); 329 // leave behind an indication that we attempted a relocation 330 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress); 331 return; 332 } 333 334 // Advance the point, noting the offset we'll have to record. 335 csize_t offset = at - locs_point(); 336 set_locs_point(at); 337 338 // Test for a couple of overflow conditions; maybe expand the buffer. 339 relocInfo* end = locs_end(); 340 relocInfo* req = end + relocInfo::length_limit; 341 // Check for (potential) overflow 342 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) { 343 req += (uint)offset / (uint)relocInfo::offset_limit(); 344 if (req >= locs_limit()) { 345 // Allocate or reallocate. 346 expand_locs(locs_count() + (req - end)); 347 // reload pointer 348 end = locs_end(); 349 } 350 } 351 352 // If the offset is giant, emit filler relocs, of type 'none', but 353 // each carrying the largest possible offset, to advance the locs_point. 354 while (offset >= relocInfo::offset_limit()) { 355 assert(end < locs_limit(), "adjust previous paragraph of code"); 356 *end++ = filler_relocInfo(); 357 offset -= filler_relocInfo().addr_offset(); 358 } 359 360 // If it's a simple reloc with no data, we'll just write (rtype | offset). 361 (*end) = relocInfo(rtype, offset, format); 362 363 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2. 364 end->initialize(this, reloc); 365 } 366 367 void CodeSection::initialize_locs(int locs_capacity) { 368 assert(_locs_start == NULL, "only one locs init step, please"); 369 // Apply a priori lower limits to relocation size: 370 csize_t min_locs = MAX2(size() / 16, (csize_t)4); 371 if (locs_capacity < min_locs) locs_capacity = min_locs; 372 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity); 373 _locs_start = locs_start; 374 _locs_end = locs_start; 375 _locs_limit = locs_start + locs_capacity; 376 _locs_own = true; 377 } 378 379 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) { 380 assert(_locs_start == NULL, "do this before locs are allocated"); 381 // Internal invariant: locs buf must be fully aligned. 382 // See copy_relocations_to() below. 383 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) { 384 ++buf; --length; 385 } 386 if (length > 0) { 387 _locs_start = buf; 388 _locs_end = buf; 389 _locs_limit = buf + length; 390 _locs_own = false; 391 } 392 } 393 394 void CodeSection::initialize_locs_from(const CodeSection* source_cs) { 395 int lcount = source_cs->locs_count(); 396 if (lcount != 0) { 397 initialize_shared_locs(source_cs->locs_start(), lcount); 398 _locs_end = _locs_limit = _locs_start + lcount; 399 assert(is_allocated(), "must have copied code already"); 400 set_locs_point(start() + source_cs->locs_point_off()); 401 } 402 assert(this->locs_count() == source_cs->locs_count(), "sanity"); 403 } 404 405 void CodeSection::expand_locs(int new_capacity) { 406 if (_locs_start == NULL) { 407 initialize_locs(new_capacity); 408 return; 409 } else { 410 int old_count = locs_count(); 411 int old_capacity = locs_capacity(); 412 if (new_capacity < old_capacity * 2) 413 new_capacity = old_capacity * 2; 414 relocInfo* locs_start; 415 if (_locs_own) { 416 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity); 417 } else { 418 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity); 419 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo)); 420 _locs_own = true; 421 } 422 _locs_start = locs_start; 423 _locs_end = locs_start + old_count; 424 _locs_limit = locs_start + new_capacity; 425 } 426 } 427 428 429 /// Support for emitting the code to its final location. 430 /// The pattern is the same for all functions. 431 /// We iterate over all the sections, padding each to alignment. 432 433 csize_t CodeBuffer::total_content_size() const { 434 csize_t size_so_far = 0; 435 for (int n = 0; n < (int)SECT_LIMIT; n++) { 436 const CodeSection* cs = code_section(n); 437 if (cs->is_empty()) continue; // skip trivial section 438 size_so_far = cs->align_at_start(size_so_far); 439 size_so_far += cs->size(); 440 } 441 return size_so_far; 442 } 443 444 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const { 445 address buf = dest->_total_start; 446 csize_t buf_offset = 0; 447 assert(dest->_total_size >= total_content_size(), "must be big enough"); 448 449 { 450 // not sure why this is here, but why not... 451 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment); 452 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment"); 453 } 454 455 const CodeSection* prev_cs = NULL; 456 CodeSection* prev_dest_cs = NULL; 457 458 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 459 // figure compact layout of each section 460 const CodeSection* cs = code_section(n); 461 csize_t csize = cs->size(); 462 463 CodeSection* dest_cs = dest->code_section(n); 464 if (!cs->is_empty()) { 465 // Compute initial padding; assign it to the previous non-empty guy. 466 // Cf. figure_expanded_capacities. 467 csize_t padding = cs->align_at_start(buf_offset) - buf_offset; 468 if (padding != 0) { 469 buf_offset += padding; 470 assert(prev_dest_cs != NULL, "sanity"); 471 prev_dest_cs->_limit += padding; 472 } 473 #ifdef ASSERT 474 if (prev_cs != NULL && prev_cs->is_frozen() && n < (SECT_LIMIT - 1)) { 475 // Make sure the ends still match up. 476 // This is important because a branch in a frozen section 477 // might target code in a following section, via a Label, 478 // and without a relocation record. See Label::patch_instructions. 479 address dest_start = buf+buf_offset; 480 csize_t start2start = cs->start() - prev_cs->start(); 481 csize_t dest_start2start = dest_start - prev_dest_cs->start(); 482 assert(start2start == dest_start2start, "cannot stretch frozen sect"); 483 } 484 #endif //ASSERT 485 prev_dest_cs = dest_cs; 486 prev_cs = cs; 487 } 488 489 debug_only(dest_cs->_start = NULL); // defeat double-initialization assert 490 dest_cs->initialize(buf+buf_offset, csize); 491 dest_cs->set_end(buf+buf_offset+csize); 492 assert(dest_cs->is_allocated(), "must always be allocated"); 493 assert(cs->is_empty() == dest_cs->is_empty(), "sanity"); 494 495 buf_offset += csize; 496 } 497 498 // Done calculating sections; did it come out to the right end? 499 assert(buf_offset == total_content_size(), "sanity"); 500 dest->verify_section_allocation(); 501 } 502 503 // Append an oop reference that keeps the class alive. 504 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) { 505 oop cl = k->klass_holder(); 506 if (cl != NULL && !oops->contains(cl)) { 507 oops->append(cl); 508 } 509 } 510 511 void CodeBuffer::finalize_oop_references(methodHandle mh) { 512 No_Safepoint_Verifier nsv; 513 514 GrowableArray<oop> oops; 515 516 // Make sure that immediate metadata records something in the OopRecorder 517 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 518 // pull code out of each section 519 CodeSection* cs = code_section(n); 520 if (cs->is_empty()) continue; // skip trivial section 521 RelocIterator iter(cs); 522 while (iter.next()) { 523 if (iter.type() == relocInfo::metadata_type) { 524 metadata_Relocation* md = iter.metadata_reloc(); 525 if (md->metadata_is_immediate()) { 526 Metadata* m = md->metadata_value(); 527 if (oop_recorder()->is_real(m)) { 528 if (m->is_methodData()) { 529 m = ((MethodData*)m)->method(); 530 } 531 if (m->is_method()) { 532 m = ((Method*)m)->method_holder(); 533 } 534 if (m->is_klass()) { 535 append_oop_references(&oops, (Klass*)m); 536 } else { 537 // XXX This will currently occur for MDO which don't 538 // have a backpointer. This has to be fixed later. 539 m->print(); 540 ShouldNotReachHere(); 541 } 542 } 543 } 544 } 545 } 546 } 547 548 if (!oop_recorder()->is_unused()) { 549 for (int i = 0; i < oop_recorder()->metadata_count(); i++) { 550 Metadata* m = oop_recorder()->metadata_at(i); 551 if (oop_recorder()->is_real(m)) { 552 if (m->is_methodData()) { 553 m = ((MethodData*)m)->method(); 554 } 555 if (m->is_method()) { 556 m = ((Method*)m)->method_holder(); 557 } 558 if (m->is_klass()) { 559 append_oop_references(&oops, (Klass*)m); 560 } else { 561 m->print(); 562 ShouldNotReachHere(); 563 } 564 } 565 } 566 567 } 568 569 // Add the class loader of Method* for the nmethod itself 570 append_oop_references(&oops, mh->method_holder()); 571 572 // Add any oops that we've found 573 Thread* thread = Thread::current(); 574 for (int i = 0; i < oops.length(); i++) { 575 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i))); 576 } 577 } 578 579 580 581 csize_t CodeBuffer::total_offset_of(CodeSection* cs) const { 582 csize_t size_so_far = 0; 583 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 584 const CodeSection* cur_cs = code_section(n); 585 if (!cur_cs->is_empty()) { 586 size_so_far = cur_cs->align_at_start(size_so_far); 587 } 588 if (cur_cs->index() == cs->index()) { 589 return size_so_far; 590 } 591 size_so_far += cur_cs->size(); 592 } 593 ShouldNotReachHere(); 594 return -1; 595 } 596 597 csize_t CodeBuffer::total_relocation_size() const { 598 csize_t lsize = copy_relocations_to(NULL); // dry run only 599 csize_t csize = total_content_size(); 600 csize_t total = RelocIterator::locs_and_index_size(csize, lsize); 601 return (csize_t) align_size_up(total, HeapWordSize); 602 } 603 604 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const { 605 address buf = NULL; 606 csize_t buf_offset = 0; 607 csize_t buf_limit = 0; 608 if (dest != NULL) { 609 buf = (address)dest->relocation_begin(); 610 buf_limit = (address)dest->relocation_end() - buf; 611 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned"); 612 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized"); 613 } 614 // if dest == NULL, this is just the sizing pass 615 616 csize_t code_end_so_far = 0; 617 csize_t code_point_so_far = 0; 618 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) { 619 // pull relocs out of each section 620 const CodeSection* cs = code_section(n); 621 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity"); 622 if (cs->is_empty()) continue; // skip trivial section 623 relocInfo* lstart = cs->locs_start(); 624 relocInfo* lend = cs->locs_end(); 625 csize_t lsize = (csize_t)( (address)lend - (address)lstart ); 626 csize_t csize = cs->size(); 627 code_end_so_far = cs->align_at_start(code_end_so_far); 628 629 if (lsize > 0) { 630 // Figure out how to advance the combined relocation point 631 // first to the beginning of this section. 632 // We'll insert one or more filler relocs to span that gap. 633 // (Don't bother to improve this by editing the first reloc's offset.) 634 csize_t new_code_point = code_end_so_far; 635 for (csize_t jump; 636 code_point_so_far < new_code_point; 637 code_point_so_far += jump) { 638 jump = new_code_point - code_point_so_far; 639 relocInfo filler = filler_relocInfo(); 640 if (jump >= filler.addr_offset()) { 641 jump = filler.addr_offset(); 642 } else { // else shrink the filler to fit 643 filler = relocInfo(relocInfo::none, jump); 644 } 645 if (buf != NULL) { 646 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds"); 647 *(relocInfo*)(buf+buf_offset) = filler; 648 } 649 buf_offset += sizeof(filler); 650 } 651 652 // Update code point and end to skip past this section: 653 csize_t last_code_point = code_end_so_far + cs->locs_point_off(); 654 assert(code_point_so_far <= last_code_point, "sanity"); 655 code_point_so_far = last_code_point; // advance past this guy's relocs 656 } 657 code_end_so_far += csize; // advance past this guy's instructions too 658 659 // Done with filler; emit the real relocations: 660 if (buf != NULL && lsize != 0) { 661 assert(buf_offset + lsize <= buf_limit, "target in bounds"); 662 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start"); 663 if (buf_offset % HeapWordSize == 0) { 664 // Use wordwise copies if possible: 665 Copy::disjoint_words((HeapWord*)lstart, 666 (HeapWord*)(buf+buf_offset), 667 (lsize + HeapWordSize-1) / HeapWordSize); 668 } else { 669 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize); 670 } 671 } 672 buf_offset += lsize; 673 } 674 675 // Align end of relocation info in target. 676 while (buf_offset % HeapWordSize != 0) { 677 if (buf != NULL) { 678 relocInfo padding = relocInfo(relocInfo::none, 0); 679 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds"); 680 *(relocInfo*)(buf+buf_offset) = padding; 681 } 682 buf_offset += sizeof(relocInfo); 683 } 684 685 assert(code_end_so_far == total_content_size(), "sanity"); 686 687 // Account for index: 688 if (buf != NULL) { 689 RelocIterator::create_index(dest->relocation_begin(), 690 buf_offset / sizeof(relocInfo), 691 dest->relocation_end()); 692 } 693 694 return buf_offset; 695 } 696 697 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) { 698 #ifndef PRODUCT 699 if (PrintNMethods && (WizardMode || Verbose)) { 700 tty->print("done with CodeBuffer:"); 701 ((CodeBuffer*)this)->print(); 702 } 703 #endif //PRODUCT 704 705 CodeBuffer dest(dest_blob); 706 assert(dest_blob->content_size() >= total_content_size(), "good sizing"); 707 this->compute_final_layout(&dest); 708 relocate_code_to(&dest); 709 710 // transfer strings and comments from buffer to blob 711 dest_blob->set_strings(_code_strings); 712 713 // Done moving code bytes; were they the right size? 714 assert(round_to(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity"); 715 716 // Flush generated code 717 ICache::invalidate_range(dest_blob->code_begin(), dest_blob->code_size()); 718 } 719 720 // Move all my code into another code buffer. Consult applicable 721 // relocs to repair embedded addresses. The layout in the destination 722 // CodeBuffer is different to the source CodeBuffer: the destination 723 // CodeBuffer gets the final layout (consts, insts, stubs in order of 724 // ascending address). 725 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const { 726 address dest_end = dest->_total_start + dest->_total_size; 727 address dest_filled = NULL; 728 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 729 // pull code out of each section 730 const CodeSection* cs = code_section(n); 731 if (cs->is_empty()) continue; // skip trivial section 732 CodeSection* dest_cs = dest->code_section(n); 733 assert(cs->size() == dest_cs->size(), "sanity"); 734 csize_t usize = dest_cs->size(); 735 csize_t wsize = align_size_up(usize, HeapWordSize); 736 assert(dest_cs->start() + wsize <= dest_end, "no overflow"); 737 // Copy the code as aligned machine words. 738 // This may also include an uninitialized partial word at the end. 739 Copy::disjoint_words((HeapWord*)cs->start(), 740 (HeapWord*)dest_cs->start(), 741 wsize / HeapWordSize); 742 743 if (dest->blob() == NULL) { 744 // Destination is a final resting place, not just another buffer. 745 // Normalize uninitialized bytes in the final padding. 746 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(), 747 Assembler::code_fill_byte()); 748 } 749 // Keep track of the highest filled address 750 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining()); 751 752 assert(cs->locs_start() != (relocInfo*)badAddress, 753 "this section carries no reloc storage, but reloc was attempted"); 754 755 // Make the new code copy use the old copy's relocations: 756 dest_cs->initialize_locs_from(cs); 757 } 758 759 // Do relocation after all sections are copied. 760 // This is necessary if the code uses constants in stubs, which are 761 // relocated when the corresponding instruction in the code (e.g., a 762 // call) is relocated. Stubs are placed behind the main code 763 // section, so that section has to be copied before relocating. 764 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) { 765 // pull code out of each section 766 const CodeSection* cs = code_section(n); 767 if (cs->is_empty()) continue; // skip trivial section 768 CodeSection* dest_cs = dest->code_section(n); 769 { // Repair the pc relative information in the code after the move 770 RelocIterator iter(dest_cs); 771 while (iter.next()) { 772 iter.reloc()->fix_relocation_after_move(this, dest); 773 } 774 } 775 } 776 777 if (dest->blob() == NULL && dest_filled != NULL) { 778 // Destination is a final resting place, not just another buffer. 779 // Normalize uninitialized bytes in the final padding. 780 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled, 781 Assembler::code_fill_byte()); 782 783 } 784 } 785 786 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs, 787 csize_t amount, 788 csize_t* new_capacity) { 789 csize_t new_total_cap = 0; 790 791 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 792 const CodeSection* sect = code_section(n); 793 794 if (!sect->is_empty()) { 795 // Compute initial padding; assign it to the previous section, 796 // even if it's empty (e.g. consts section can be empty). 797 // Cf. compute_final_layout 798 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap; 799 if (padding != 0) { 800 new_total_cap += padding; 801 assert(n - 1 >= SECT_FIRST, "sanity"); 802 new_capacity[n - 1] += padding; 803 } 804 } 805 806 csize_t exp = sect->size(); // 100% increase 807 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase 808 if (sect == which_cs) { 809 if (exp < amount) exp = amount; 810 if (StressCodeBuffers) exp = amount; // expand only slightly 811 } else if (n == SECT_INSTS) { 812 // scale down inst increases to a more modest 25% 813 exp = 4*K + ((exp - 4*K) >> 2); 814 if (StressCodeBuffers) exp = amount / 2; // expand only slightly 815 } else if (sect->is_empty()) { 816 // do not grow an empty secondary section 817 exp = 0; 818 } 819 // Allow for inter-section slop: 820 exp += CodeSection::end_slop(); 821 csize_t new_cap = sect->size() + exp; 822 if (new_cap < sect->capacity()) { 823 // No need to expand after all. 824 new_cap = sect->capacity(); 825 } 826 new_capacity[n] = new_cap; 827 new_total_cap += new_cap; 828 } 829 830 return new_total_cap; 831 } 832 833 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) { 834 #ifndef PRODUCT 835 if (PrintNMethods && (WizardMode || Verbose)) { 836 tty->print("expanding CodeBuffer:"); 837 this->print(); 838 } 839 840 if (StressCodeBuffers && blob() != NULL) { 841 static int expand_count = 0; 842 if (expand_count >= 0) expand_count += 1; 843 if (expand_count > 100 && is_power_of_2(expand_count)) { 844 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count); 845 // simulate an occasional allocation failure: 846 free_blob(); 847 } 848 } 849 #endif //PRODUCT 850 851 // Resizing must be allowed 852 { 853 if (blob() == NULL) return; // caller must check for blob == NULL 854 for (int n = 0; n < (int)SECT_LIMIT; n++) { 855 guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen"); 856 } 857 } 858 859 // Figure new capacity for each section. 860 csize_t new_capacity[SECT_LIMIT]; 861 csize_t new_total_cap 862 = figure_expanded_capacities(which_cs, amount, new_capacity); 863 864 // Create a new (temporary) code buffer to hold all the new data 865 CodeBuffer cb(name(), new_total_cap, 0); 866 if (cb.blob() == NULL) { 867 // Failed to allocate in code cache. 868 free_blob(); 869 return; 870 } 871 872 // Create an old code buffer to remember which addresses used to go where. 873 // This will be useful when we do final assembly into the code cache, 874 // because we will need to know how to warp any internal address that 875 // has been created at any time in this CodeBuffer's past. 876 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size); 877 bxp->take_over_code_from(this); // remember the old undersized blob 878 DEBUG_ONLY(this->_blob = NULL); // silence a later assert 879 bxp->_before_expand = this->_before_expand; 880 this->_before_expand = bxp; 881 882 // Give each section its required (expanded) capacity. 883 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) { 884 CodeSection* cb_sect = cb.code_section(n); 885 CodeSection* this_sect = code_section(n); 886 if (new_capacity[n] == 0) continue; // already nulled out 887 if (n != SECT_INSTS) { 888 cb.initialize_section_size(cb_sect, new_capacity[n]); 889 } 890 assert(cb_sect->capacity() >= new_capacity[n], "big enough"); 891 address cb_start = cb_sect->start(); 892 cb_sect->set_end(cb_start + this_sect->size()); 893 if (this_sect->mark() == NULL) { 894 cb_sect->clear_mark(); 895 } else { 896 cb_sect->set_mark(cb_start + this_sect->mark_off()); 897 } 898 } 899 900 // Move all the code and relocations to the new blob: 901 relocate_code_to(&cb); 902 903 // Copy the temporary code buffer into the current code buffer. 904 // Basically, do {*this = cb}, except for some control information. 905 this->take_over_code_from(&cb); 906 cb.set_blob(NULL); 907 908 // Zap the old code buffer contents, to avoid mistakenly using them. 909 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size, 910 badCodeHeapFreeVal)); 911 912 _decode_begin = NULL; // sanity 913 914 // Make certain that the new sections are all snugly inside the new blob. 915 verify_section_allocation(); 916 917 #ifndef PRODUCT 918 if (PrintNMethods && (WizardMode || Verbose)) { 919 tty->print("expanded CodeBuffer:"); 920 this->print(); 921 } 922 #endif //PRODUCT 923 } 924 925 void CodeBuffer::take_over_code_from(CodeBuffer* cb) { 926 // Must already have disposed of the old blob somehow. 927 assert(blob() == NULL, "must be empty"); 928 #ifdef ASSERT 929 930 #endif 931 // Take the new blob away from cb. 932 set_blob(cb->blob()); 933 // Take over all the section pointers. 934 for (int n = 0; n < (int)SECT_LIMIT; n++) { 935 CodeSection* cb_sect = cb->code_section(n); 936 CodeSection* this_sect = code_section(n); 937 this_sect->take_over_code_from(cb_sect); 938 } 939 _overflow_arena = cb->_overflow_arena; 940 // Make sure the old cb won't try to use it or free it. 941 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress); 942 } 943 944 void CodeBuffer::verify_section_allocation() { 945 address tstart = _total_start; 946 if (tstart == badAddress) return; // smashed by set_blob(NULL) 947 address tend = tstart + _total_size; 948 if (_blob != NULL) { 949 950 guarantee(tstart >= _blob->content_begin(), "sanity"); 951 guarantee(tend <= _blob->content_end(), "sanity"); 952 } 953 // Verify disjointness. 954 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 955 CodeSection* sect = code_section(n); 956 if (!sect->is_allocated() || sect->is_empty()) continue; 957 guarantee((intptr_t)sect->start() % sect->alignment() == 0 958 || sect->is_empty() || _blob == NULL, 959 "start is aligned"); 960 for (int m = (int) SECT_FIRST; m < (int) SECT_LIMIT; m++) { 961 CodeSection* other = code_section(m); 962 if (!other->is_allocated() || other == sect) continue; 963 guarantee(!other->contains(sect->start() ), "sanity"); 964 // limit is an exclusive address and can be the start of another 965 // section. 966 guarantee(!other->contains(sect->limit() - 1), "sanity"); 967 } 968 guarantee(sect->end() <= tend, "sanity"); 969 guarantee(sect->end() <= sect->limit(), "sanity"); 970 } 971 } 972 973 void CodeBuffer::log_section_sizes(const char* name) { 974 if (xtty != NULL) { 975 // log info about buffer usage 976 xtty->print_cr("<blob name='%s' size='%d'>", name, _total_size); 977 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) { 978 CodeSection* sect = code_section(n); 979 if (!sect->is_allocated() || sect->is_empty()) continue; 980 xtty->print_cr("<sect index='%d' size='" SIZE_FORMAT "' free='" SIZE_FORMAT "'/>", 981 n, sect->limit() - sect->start(), sect->limit() - sect->end()); 982 } 983 xtty->print_cr("</blob>"); 984 } 985 } 986 987 #ifndef PRODUCT 988 989 void CodeSection::dump() { 990 address ptr = start(); 991 for (csize_t step; ptr < end(); ptr += step) { 992 step = end() - ptr; 993 if (step > jintSize * 4) step = jintSize * 4; 994 tty->print(INTPTR_FORMAT ": ", p2i(ptr)); 995 while (step > 0) { 996 tty->print(" " PTR32_FORMAT, *(jint*)ptr); 997 ptr += jintSize; 998 } 999 tty->cr(); 1000 } 1001 } 1002 1003 1004 void CodeSection::decode() { 1005 Disassembler::decode(start(), end()); 1006 } 1007 1008 1009 void CodeBuffer::block_comment(intptr_t offset, const char * comment) { 1010 _code_strings.add_comment(offset, comment); 1011 } 1012 1013 const char* CodeBuffer::code_string(const char* str) { 1014 return _code_strings.add_string(str); 1015 } 1016 1017 class CodeString: public CHeapObj<mtCode> { 1018 private: 1019 friend class CodeStrings; 1020 const char * _string; 1021 CodeString* _next; 1022 intptr_t _offset; 1023 1024 ~CodeString() { 1025 assert(_next == NULL, "wrong interface for freeing list"); 1026 os::free((void*)_string, mtCode); 1027 } 1028 1029 bool is_comment() const { return _offset >= 0; } 1030 1031 public: 1032 CodeString(const char * string, intptr_t offset = -1) 1033 : _next(NULL), _offset(offset) { 1034 _string = os::strdup(string, mtCode); 1035 } 1036 1037 const char * string() const { return _string; } 1038 intptr_t offset() const { assert(_offset >= 0, "offset for non comment?"); return _offset; } 1039 CodeString* next() const { return _next; } 1040 1041 void set_next(CodeString* next) { _next = next; } 1042 1043 CodeString* first_comment() { 1044 if (is_comment()) { 1045 return this; 1046 } else { 1047 return next_comment(); 1048 } 1049 } 1050 CodeString* next_comment() const { 1051 CodeString* s = _next; 1052 while (s != NULL && !s->is_comment()) { 1053 s = s->_next; 1054 } 1055 return s; 1056 } 1057 }; 1058 1059 CodeString* CodeStrings::find(intptr_t offset) const { 1060 CodeString* a = _strings->first_comment(); 1061 while (a != NULL && a->offset() != offset) { 1062 a = a->next_comment(); 1063 } 1064 return a; 1065 } 1066 1067 // Convenience for add_comment. 1068 CodeString* CodeStrings::find_last(intptr_t offset) const { 1069 CodeString* a = find(offset); 1070 if (a != NULL) { 1071 CodeString* c = NULL; 1072 while (((c = a->next_comment()) != NULL) && (c->offset() == offset)) { 1073 a = c; 1074 } 1075 } 1076 return a; 1077 } 1078 1079 void CodeStrings::add_comment(intptr_t offset, const char * comment) { 1080 check_valid(); 1081 CodeString* c = new CodeString(comment, offset); 1082 CodeString* inspos = (_strings == NULL) ? NULL : find_last(offset); 1083 1084 if (inspos) { 1085 // insert after already existing comments with same offset 1086 c->set_next(inspos->next()); 1087 inspos->set_next(c); 1088 } else { 1089 // no comments with such offset, yet. Insert before anything else. 1090 c->set_next(_strings); 1091 _strings = c; 1092 } 1093 } 1094 1095 void CodeStrings::assign(CodeStrings& other) { 1096 other.check_valid(); 1097 // Cannot do following because CodeStrings constructor is not alway run! 1098 assert(is_null(), "Cannot assign onto non-empty CodeStrings"); 1099 _strings = other._strings; 1100 other.set_null_and_invalidate(); 1101 } 1102 1103 // Deep copy of CodeStrings for consistent memory management. 1104 // Only used for actual disassembly so this is cheaper than reference counting 1105 // for the "normal" fastdebug case. 1106 void CodeStrings::copy(CodeStrings& other) { 1107 other.check_valid(); 1108 check_valid(); 1109 assert(is_null(), "Cannot copy onto non-empty CodeStrings"); 1110 CodeString* n = other._strings; 1111 CodeString** ps = &_strings; 1112 while (n != NULL) { 1113 *ps = new CodeString(n->string(),n->offset()); 1114 ps = &((*ps)->_next); 1115 n = n->next(); 1116 } 1117 } 1118 1119 void CodeStrings::print_block_comment(outputStream* stream, intptr_t offset) const { 1120 check_valid(); 1121 if (_strings != NULL) { 1122 CodeString* c = find(offset); 1123 while (c && c->offset() == offset) { 1124 stream->bol(); 1125 stream->print(" ;; "); 1126 stream->print_cr("%s", c->string()); 1127 c = c->next_comment(); 1128 } 1129 } 1130 } 1131 1132 // Also sets isNull() 1133 void CodeStrings::free() { 1134 CodeString* n = _strings; 1135 while (n) { 1136 // unlink the node from the list saving a pointer to the next 1137 CodeString* p = n->next(); 1138 n->set_next(NULL); 1139 delete n; 1140 n = p; 1141 } 1142 set_null_and_invalidate(); 1143 } 1144 1145 const char* CodeStrings::add_string(const char * string) { 1146 check_valid(); 1147 CodeString* s = new CodeString(string); 1148 s->set_next(_strings); 1149 _strings = s; 1150 assert(s->string() != NULL, "should have a string"); 1151 return s->string(); 1152 } 1153 1154 void CodeBuffer::decode() { 1155 ttyLocker ttyl; 1156 Disassembler::decode(decode_begin(), insts_end()); 1157 _decode_begin = insts_end(); 1158 } 1159 1160 1161 void CodeBuffer::skip_decode() { 1162 _decode_begin = insts_end(); 1163 } 1164 1165 1166 void CodeBuffer::decode_all() { 1167 ttyLocker ttyl; 1168 for (int n = 0; n < (int)SECT_LIMIT; n++) { 1169 // dump contents of each section 1170 CodeSection* cs = code_section(n); 1171 tty->print_cr("! %s:", code_section_name(n)); 1172 if (cs != consts()) 1173 cs->decode(); 1174 else 1175 cs->dump(); 1176 } 1177 } 1178 1179 1180 void CodeSection::print(const char* name) { 1181 csize_t locs_size = locs_end() - locs_start(); 1182 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s", 1183 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity(), 1184 is_frozen()? " [frozen]": ""); 1185 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d", 1186 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off()); 1187 if (PrintRelocations) { 1188 RelocIterator iter(this); 1189 iter.print(); 1190 } 1191 } 1192 1193 void CodeBuffer::print() { 1194 if (this == NULL) { 1195 tty->print_cr("NULL CodeBuffer pointer"); 1196 return; 1197 } 1198 1199 tty->print_cr("CodeBuffer:"); 1200 for (int n = 0; n < (int)SECT_LIMIT; n++) { 1201 // print each section 1202 CodeSection* cs = code_section(n); 1203 cs->print(code_section_name(n)); 1204 } 1205 } 1206 1207 #endif // PRODUCT