1 /* 2 * Copyright (c) 1997, 2015, 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 "gc/shared/gcLocker.hpp" 29 #include "oops/methodData.hpp" 30 #include "oops/oop.inline.hpp" 31 #include "runtime/icache.hpp" 32 #include "utilities/copy.hpp" 33 #include "utilities/xmlstream.hpp" 34 35 // The structure of a CodeSection: 36 // 37 // _start -> +----------------+ 38 // | machine code...| 39 // _end -> |----------------| 40 // | | 41 // | (empty) | 42 // | | 43 // | | 44 // +----------------+ 45 // _limit -> | | 46 // 47 // _locs_start -> +----------------+ 48 // |reloc records...| 49 // |----------------| 50 // _locs_end -> | | 51 // | | 52 // | (empty) | 53 // | | 54 // | | 55 // +----------------+ 56 // _locs_limit -> | | 57 // The _end (resp. _limit) pointer refers to the first 58 // unused (resp. unallocated) byte. 59 60 // The structure of the CodeBuffer while code is being accumulated: 61 // 62 // _total_start -> \ 63 // _insts._start -> +----------------+ 64 // | | 65 // | Code | 66 // | | 67 // _stubs._start -> |----------------| 68 // | | 69 // | Stubs | (also handlers for deopt/exception) 70 // | | 71 // _consts._start -> |----------------| 72 // | | 73 // | Constants | 74 // | | 75 // +----------------+ 76 // + _total_size -> | | 77 // 78 // When the code and relocations are copied to the code cache, 79 // the empty parts of each section are removed, and everything 80 // is copied into contiguous locations. 81 82 typedef CodeBuffer::csize_t csize_t; // file-local definition 83 84 // External buffer, in a predefined CodeBlob. 85 // Important: The code_start must be taken exactly, and not realigned. 86 CodeBuffer::CodeBuffer(CodeBlob* blob) { 87 initialize_misc("static buffer"); 88 initialize(blob->content_begin(), blob->content_size()); 89 verify_section_allocation(); 90 } 91 92 void CodeBuffer::initialize(csize_t code_size, csize_t locs_size) { 93 // Compute maximal alignment. 94 int align = _insts.alignment(); 95 // Always allow for empty slop around each section. 96 int slop = (int) CodeSection::end_slop(); 97 98 assert(blob() == NULL, "only once"); 99 set_blob(BufferBlob::create(_name, code_size + (align+slop) * (SECT_LIMIT+1))); 100 if (blob() == NULL) { 101 // The assembler constructor will throw a fatal on an empty CodeBuffer. 102 return; // caller must test this 103 } 104 105 // Set up various pointers into the blob. 106 initialize(_total_start, _total_size); 107 108 assert((uintptr_t)insts_begin() % CodeEntryAlignment == 0, "instruction start not code entry aligned"); 109 110 pd_initialize(); 111 112 if (locs_size != 0) { 113 _insts.initialize_locs(locs_size / sizeof(relocInfo)); 114 } 115 116 verify_section_allocation(); 117 } 118 119 120 CodeBuffer::~CodeBuffer() { 121 verify_section_allocation(); 122 123 // If we allocate our code buffer from the CodeCache 124 // via a BufferBlob, and it's not permanent, then 125 // free the BufferBlob. 126 // The rest of the memory will be freed when the ResourceObj 127 // is released. 128 for (CodeBuffer* cb = this; cb != NULL; cb = cb->before_expand()) { 129 // Previous incarnations of this buffer are held live, so that internal 130 // addresses constructed before expansions will not be confused. 131 cb->free_blob(); 132 } 133 134 // free any overflow storage 135 delete _overflow_arena; 136 137 // Claim is that stack allocation ensures resources are cleaned up. 138 // This is resource clean up, let's hope that all were properly copied out. 139 free_strings(); 140 141 #ifdef ASSERT 142 // Save allocation type to execute assert in ~ResourceObj() 143 // which is called after this destructor. 144 assert(_default_oop_recorder.allocated_on_stack(), "should be embedded object"); 145 ResourceObj::allocation_type at = _default_oop_recorder.get_allocation_type(); 146 Copy::fill_to_bytes(this, sizeof(*this), badResourceValue); 147 ResourceObj::set_allocation_type((address)(&_default_oop_recorder), at); 148 #endif 149 } 150 151 void CodeBuffer::initialize_oop_recorder(OopRecorder* r) { 152 assert(_oop_recorder == &_default_oop_recorder && _default_oop_recorder.is_unused(), "do this once"); 153 DEBUG_ONLY(_default_oop_recorder.freeze()); // force unused OR to be frozen 154 _oop_recorder = r; 155 } 156 157 void CodeBuffer::initialize_section_size(CodeSection* cs, csize_t size) { 158 assert(cs != &_insts, "insts is the memory provider, not the consumer"); 159 csize_t slop = CodeSection::end_slop(); // margin between sections 160 int align = cs->alignment(); 161 assert(is_power_of_2(align), "sanity"); 162 address start = _insts._start; 163 address limit = _insts._limit; 164 address middle = limit - size; 165 middle -= (intptr_t)middle & (align-1); // align the division point downward 166 guarantee(middle - slop > start, "need enough space to divide up"); 167 _insts._limit = middle - slop; // subtract desired space, plus slop 168 cs->initialize(middle, limit - middle); 169 assert(cs->start() == middle, "sanity"); 170 assert(cs->limit() == limit, "sanity"); 171 // give it some relocations to start with, if the main section has them 172 if (_insts.has_locs()) cs->initialize_locs(1); 173 } 174 175 void CodeBuffer::freeze_section(CodeSection* cs) { 176 CodeSection* next_cs = (cs == consts())? NULL: code_section(cs->index()+1); 177 csize_t frozen_size = cs->size(); 178 if (next_cs != NULL) { 179 frozen_size = next_cs->align_at_start(frozen_size); 180 } 181 address old_limit = cs->limit(); 182 address new_limit = cs->start() + frozen_size; 183 relocInfo* old_locs_limit = cs->locs_limit(); 184 relocInfo* new_locs_limit = cs->locs_end(); 185 // Patch the limits. 186 cs->_limit = new_limit; 187 cs->_locs_limit = new_locs_limit; 188 cs->_frozen = true; 189 if (!next_cs->is_allocated() && !next_cs->is_frozen()) { 190 // Give remaining buffer space to the following section. 191 next_cs->initialize(new_limit, old_limit - new_limit); 192 next_cs->initialize_shared_locs(new_locs_limit, 193 old_locs_limit - new_locs_limit); 194 } 195 } 196 197 void CodeBuffer::set_blob(BufferBlob* blob) { 198 _blob = blob; 199 if (blob != NULL) { 200 address start = blob->content_begin(); 201 address end = blob->content_end(); 202 // Round up the starting address. 203 int align = _insts.alignment(); 204 start += (-(intptr_t)start) & (align-1); 205 _total_start = start; 206 _total_size = end - start; 207 } else { 208 #ifdef ASSERT 209 // Clean out dangling pointers. 210 _total_start = badAddress; 211 _consts._start = _consts._end = badAddress; 212 _insts._start = _insts._end = badAddress; 213 _stubs._start = _stubs._end = badAddress; 214 #endif //ASSERT 215 } 216 } 217 218 void CodeBuffer::free_blob() { 219 if (_blob != NULL) { 220 BufferBlob::free(_blob); 221 set_blob(NULL); 222 } 223 } 224 225 const char* CodeBuffer::code_section_name(int n) { 226 #ifdef PRODUCT 227 return NULL; 228 #else //PRODUCT 229 switch (n) { 230 case SECT_CONSTS: return "consts"; 231 case SECT_INSTS: return "insts"; 232 case SECT_STUBS: return "stubs"; 233 default: return NULL; 234 } 235 #endif //PRODUCT 236 } 237 238 int CodeBuffer::section_index_of(address addr) const { 239 for (int n = 0; n < (int)SECT_LIMIT; n++) { 240 const CodeSection* cs = code_section(n); 241 if (cs->allocates(addr)) return n; 242 } 243 return SECT_NONE; 244 } 245 246 int CodeBuffer::locator(address addr) const { 247 for (int n = 0; n < (int)SECT_LIMIT; n++) { 248 const CodeSection* cs = code_section(n); 249 if (cs->allocates(addr)) { 250 return locator(addr - cs->start(), n); 251 } 252 } 253 return -1; 254 } 255 256 address CodeBuffer::locator_address(int locator) const { 257 if (locator < 0) return NULL; 258 address start = code_section(locator_sect(locator))->start(); 259 return start + locator_pos(locator); 260 } 261 262 bool CodeBuffer::is_backward_branch(Label& L) { 263 return L.is_bound() && insts_end() <= locator_address(L.loc()); 264 } 265 266 address CodeBuffer::decode_begin() { 267 address begin = _insts.start(); 268 if (_decode_begin != NULL && _decode_begin > begin) 269 begin = _decode_begin; 270 return begin; 271 } 272 273 274 GrowableArray<int>* CodeBuffer::create_patch_overflow() { 275 if (_overflow_arena == NULL) { 276 _overflow_arena = new (mtCode) Arena(mtCode); 277 } 278 return new (_overflow_arena) GrowableArray<int>(_overflow_arena, 8, 0, 0); 279 } 280 281 282 // Helper function for managing labels and their target addresses. 283 // Returns a sensible address, and if it is not the label's final 284 // address, notes the dependency (at 'branch_pc') on the label. 285 address CodeSection::target(Label& L, address branch_pc) { 286 if (L.is_bound()) { 287 int loc = L.loc(); 288 if (index() == CodeBuffer::locator_sect(loc)) { 289 return start() + CodeBuffer::locator_pos(loc); 290 } else { 291 return outer()->locator_address(loc); 292 } 293 } else { 294 assert(allocates2(branch_pc), "sanity"); 295 address base = start(); 296 int patch_loc = CodeBuffer::locator(branch_pc - base, index()); 297 L.add_patch_at(outer(), patch_loc); 298 299 // Need to return a pc, doesn't matter what it is since it will be 300 // replaced during resolution later. 301 // Don't return NULL or badAddress, since branches shouldn't overflow. 302 // Don't return base either because that could overflow displacements 303 // for shorter branches. It will get checked when bound. 304 return branch_pc; 305 } 306 } 307 308 void CodeSection::relocate(address at, relocInfo::relocType rtype, int format, jint method_index) { 309 RelocationHolder rh; 310 switch (rtype) { 311 case relocInfo::none: return; 312 case relocInfo::opt_virtual_call_type: { 313 rh = opt_virtual_call_Relocation::spec(method_index); 314 break; 315 } 316 case relocInfo::static_call_type: { 317 rh = static_call_Relocation::spec(method_index); 318 break; 319 } 320 case relocInfo::virtual_call_type: { 321 assert(method_index == 0, "resolved method overriding is not supported"); 322 rh = Relocation::spec_simple(rtype); 323 break; 324 } 325 default: { 326 rh = Relocation::spec_simple(rtype); 327 break; 328 } 329 } 330 relocate(at, rh, format); 331 } 332 333 void CodeSection::relocate(address at, RelocationHolder const& spec, int format) { 334 Relocation* reloc = spec.reloc(); 335 relocInfo::relocType rtype = (relocInfo::relocType) reloc->type(); 336 if (rtype == relocInfo::none) return; 337 338 // The assertion below has been adjusted, to also work for 339 // relocation for fixup. Sometimes we want to put relocation 340 // information for the next instruction, since it will be patched 341 // with a call. 342 assert(start() <= at && at <= end()+1, 343 "cannot relocate data outside code boundaries"); 344 345 if (!has_locs()) { 346 // no space for relocation information provided => code cannot be 347 // relocated. Make sure that relocate is only called with rtypes 348 // that can be ignored for this kind of code. 349 assert(rtype == relocInfo::none || 350 rtype == relocInfo::runtime_call_type || 351 rtype == relocInfo::internal_word_type|| 352 rtype == relocInfo::section_word_type || 353 rtype == relocInfo::external_word_type, 354 "code needs relocation information"); 355 // leave behind an indication that we attempted a relocation 356 DEBUG_ONLY(_locs_start = _locs_limit = (relocInfo*)badAddress); 357 return; 358 } 359 360 // Advance the point, noting the offset we'll have to record. 361 csize_t offset = at - locs_point(); 362 set_locs_point(at); 363 364 // Test for a couple of overflow conditions; maybe expand the buffer. 365 relocInfo* end = locs_end(); 366 relocInfo* req = end + relocInfo::length_limit; 367 // Check for (potential) overflow 368 if (req >= locs_limit() || offset >= relocInfo::offset_limit()) { 369 req += (uint)offset / (uint)relocInfo::offset_limit(); 370 if (req >= locs_limit()) { 371 // Allocate or reallocate. 372 expand_locs(locs_count() + (req - end)); 373 // reload pointer 374 end = locs_end(); 375 } 376 } 377 378 // If the offset is giant, emit filler relocs, of type 'none', but 379 // each carrying the largest possible offset, to advance the locs_point. 380 while (offset >= relocInfo::offset_limit()) { 381 assert(end < locs_limit(), "adjust previous paragraph of code"); 382 *end++ = filler_relocInfo(); 383 offset -= filler_relocInfo().addr_offset(); 384 } 385 386 // If it's a simple reloc with no data, we'll just write (rtype | offset). 387 (*end) = relocInfo(rtype, offset, format); 388 389 // If it has data, insert the prefix, as (data_prefix_tag | data1), data2. 390 end->initialize(this, reloc); 391 } 392 393 void CodeSection::initialize_locs(int locs_capacity) { 394 assert(_locs_start == NULL, "only one locs init step, please"); 395 // Apply a priori lower limits to relocation size: 396 csize_t min_locs = MAX2(size() / 16, (csize_t)4); 397 if (locs_capacity < min_locs) locs_capacity = min_locs; 398 relocInfo* locs_start = NEW_RESOURCE_ARRAY(relocInfo, locs_capacity); 399 _locs_start = locs_start; 400 _locs_end = locs_start; 401 _locs_limit = locs_start + locs_capacity; 402 _locs_own = true; 403 } 404 405 void CodeSection::initialize_shared_locs(relocInfo* buf, int length) { 406 assert(_locs_start == NULL, "do this before locs are allocated"); 407 // Internal invariant: locs buf must be fully aligned. 408 // See copy_relocations_to() below. 409 while ((uintptr_t)buf % HeapWordSize != 0 && length > 0) { 410 ++buf; --length; 411 } 412 if (length > 0) { 413 _locs_start = buf; 414 _locs_end = buf; 415 _locs_limit = buf + length; 416 _locs_own = false; 417 } 418 } 419 420 void CodeSection::initialize_locs_from(const CodeSection* source_cs) { 421 int lcount = source_cs->locs_count(); 422 if (lcount != 0) { 423 initialize_shared_locs(source_cs->locs_start(), lcount); 424 _locs_end = _locs_limit = _locs_start + lcount; 425 assert(is_allocated(), "must have copied code already"); 426 set_locs_point(start() + source_cs->locs_point_off()); 427 } 428 assert(this->locs_count() == source_cs->locs_count(), "sanity"); 429 } 430 431 void CodeSection::expand_locs(int new_capacity) { 432 if (_locs_start == NULL) { 433 initialize_locs(new_capacity); 434 return; 435 } else { 436 int old_count = locs_count(); 437 int old_capacity = locs_capacity(); 438 if (new_capacity < old_capacity * 2) 439 new_capacity = old_capacity * 2; 440 relocInfo* locs_start; 441 if (_locs_own) { 442 locs_start = REALLOC_RESOURCE_ARRAY(relocInfo, _locs_start, old_capacity, new_capacity); 443 } else { 444 locs_start = NEW_RESOURCE_ARRAY(relocInfo, new_capacity); 445 Copy::conjoint_jbytes(_locs_start, locs_start, old_capacity * sizeof(relocInfo)); 446 _locs_own = true; 447 } 448 _locs_start = locs_start; 449 _locs_end = locs_start + old_count; 450 _locs_limit = locs_start + new_capacity; 451 } 452 } 453 454 455 /// Support for emitting the code to its final location. 456 /// The pattern is the same for all functions. 457 /// We iterate over all the sections, padding each to alignment. 458 459 csize_t CodeBuffer::total_content_size() const { 460 csize_t size_so_far = 0; 461 for (int n = 0; n < (int)SECT_LIMIT; n++) { 462 const CodeSection* cs = code_section(n); 463 if (cs->is_empty()) continue; // skip trivial section 464 size_so_far = cs->align_at_start(size_so_far); 465 size_so_far += cs->size(); 466 } 467 return size_so_far; 468 } 469 470 void CodeBuffer::compute_final_layout(CodeBuffer* dest) const { 471 address buf = dest->_total_start; 472 csize_t buf_offset = 0; 473 assert(dest->_total_size >= total_content_size(), "must be big enough"); 474 475 { 476 // not sure why this is here, but why not... 477 int alignSize = MAX2((intx) sizeof(jdouble), CodeEntryAlignment); 478 assert( (dest->_total_start - _insts.start()) % alignSize == 0, "copy must preserve alignment"); 479 } 480 481 const CodeSection* prev_cs = NULL; 482 CodeSection* prev_dest_cs = NULL; 483 484 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 485 // figure compact layout of each section 486 const CodeSection* cs = code_section(n); 487 csize_t csize = cs->size(); 488 489 CodeSection* dest_cs = dest->code_section(n); 490 if (!cs->is_empty()) { 491 // Compute initial padding; assign it to the previous non-empty guy. 492 // Cf. figure_expanded_capacities. 493 csize_t padding = cs->align_at_start(buf_offset) - buf_offset; 494 if (padding != 0) { 495 buf_offset += padding; 496 assert(prev_dest_cs != NULL, "sanity"); 497 prev_dest_cs->_limit += padding; 498 } 499 #ifdef ASSERT 500 if (prev_cs != NULL && prev_cs->is_frozen() && n < (SECT_LIMIT - 1)) { 501 // Make sure the ends still match up. 502 // This is important because a branch in a frozen section 503 // might target code in a following section, via a Label, 504 // and without a relocation record. See Label::patch_instructions. 505 address dest_start = buf+buf_offset; 506 csize_t start2start = cs->start() - prev_cs->start(); 507 csize_t dest_start2start = dest_start - prev_dest_cs->start(); 508 assert(start2start == dest_start2start, "cannot stretch frozen sect"); 509 } 510 #endif //ASSERT 511 prev_dest_cs = dest_cs; 512 prev_cs = cs; 513 } 514 515 debug_only(dest_cs->_start = NULL); // defeat double-initialization assert 516 dest_cs->initialize(buf+buf_offset, csize); 517 dest_cs->set_end(buf+buf_offset+csize); 518 assert(dest_cs->is_allocated(), "must always be allocated"); 519 assert(cs->is_empty() == dest_cs->is_empty(), "sanity"); 520 521 buf_offset += csize; 522 } 523 524 // Done calculating sections; did it come out to the right end? 525 assert(buf_offset == total_content_size(), "sanity"); 526 dest->verify_section_allocation(); 527 } 528 529 // Append an oop reference that keeps the class alive. 530 static void append_oop_references(GrowableArray<oop>* oops, Klass* k) { 531 oop cl = k->klass_holder(); 532 if (cl != NULL && !oops->contains(cl)) { 533 oops->append(cl); 534 } 535 } 536 537 void CodeBuffer::finalize_oop_references(const methodHandle& mh) { 538 No_Safepoint_Verifier nsv; 539 540 GrowableArray<oop> oops; 541 542 // Make sure that immediate metadata records something in the OopRecorder 543 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 544 // pull code out of each section 545 CodeSection* cs = code_section(n); 546 if (cs->is_empty()) continue; // skip trivial section 547 RelocIterator iter(cs); 548 while (iter.next()) { 549 if (iter.type() == relocInfo::metadata_type) { 550 metadata_Relocation* md = iter.metadata_reloc(); 551 if (md->metadata_is_immediate()) { 552 Metadata* m = md->metadata_value(); 553 if (oop_recorder()->is_real(m)) { 554 if (m->is_methodData()) { 555 m = ((MethodData*)m)->method(); 556 } 557 if (m->is_method()) { 558 m = ((Method*)m)->method_holder(); 559 } 560 if (m->is_klass()) { 561 append_oop_references(&oops, (Klass*)m); 562 } else { 563 // XXX This will currently occur for MDO which don't 564 // have a backpointer. This has to be fixed later. 565 m->print(); 566 ShouldNotReachHere(); 567 } 568 } 569 } 570 } 571 } 572 } 573 574 if (!oop_recorder()->is_unused()) { 575 for (int i = 0; i < oop_recorder()->metadata_count(); i++) { 576 Metadata* m = oop_recorder()->metadata_at(i); 577 if (oop_recorder()->is_real(m)) { 578 if (m->is_methodData()) { 579 m = ((MethodData*)m)->method(); 580 } 581 if (m->is_method()) { 582 m = ((Method*)m)->method_holder(); 583 } 584 if (m->is_klass()) { 585 append_oop_references(&oops, (Klass*)m); 586 } else { 587 m->print(); 588 ShouldNotReachHere(); 589 } 590 } 591 } 592 593 } 594 595 // Add the class loader of Method* for the nmethod itself 596 append_oop_references(&oops, mh->method_holder()); 597 598 // Add any oops that we've found 599 Thread* thread = Thread::current(); 600 for (int i = 0; i < oops.length(); i++) { 601 oop_recorder()->find_index((jobject)thread->handle_area()->allocate_handle(oops.at(i))); 602 } 603 } 604 605 606 607 csize_t CodeBuffer::total_offset_of(CodeSection* cs) const { 608 csize_t size_so_far = 0; 609 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 610 const CodeSection* cur_cs = code_section(n); 611 if (!cur_cs->is_empty()) { 612 size_so_far = cur_cs->align_at_start(size_so_far); 613 } 614 if (cur_cs->index() == cs->index()) { 615 return size_so_far; 616 } 617 size_so_far += cur_cs->size(); 618 } 619 ShouldNotReachHere(); 620 return -1; 621 } 622 623 csize_t CodeBuffer::total_relocation_size() const { 624 csize_t lsize = copy_relocations_to(NULL); // dry run only 625 csize_t csize = total_content_size(); 626 csize_t total = RelocIterator::locs_and_index_size(csize, lsize); 627 return (csize_t) align_size_up(total, HeapWordSize); 628 } 629 630 csize_t CodeBuffer::copy_relocations_to(address buf, csize_t buf_limit, bool only_inst) const { 631 csize_t buf_offset = 0; 632 csize_t code_end_so_far = 0; 633 csize_t code_point_so_far = 0; 634 635 assert((uintptr_t)buf % HeapWordSize == 0, "buf must be fully aligned"); 636 assert(buf_limit % HeapWordSize == 0, "buf must be evenly sized"); 637 638 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) { 639 if (only_inst && (n != (int)SECT_INSTS)) { 640 // Need only relocation info for code. 641 continue; 642 } 643 // pull relocs out of each section 644 const CodeSection* cs = code_section(n); 645 assert(!(cs->is_empty() && cs->locs_count() > 0), "sanity"); 646 if (cs->is_empty()) continue; // skip trivial section 647 relocInfo* lstart = cs->locs_start(); 648 relocInfo* lend = cs->locs_end(); 649 csize_t lsize = (csize_t)( (address)lend - (address)lstart ); 650 csize_t csize = cs->size(); 651 code_end_so_far = cs->align_at_start(code_end_so_far); 652 653 if (lsize > 0) { 654 // Figure out how to advance the combined relocation point 655 // first to the beginning of this section. 656 // We'll insert one or more filler relocs to span that gap. 657 // (Don't bother to improve this by editing the first reloc's offset.) 658 csize_t new_code_point = code_end_so_far; 659 for (csize_t jump; 660 code_point_so_far < new_code_point; 661 code_point_so_far += jump) { 662 jump = new_code_point - code_point_so_far; 663 relocInfo filler = filler_relocInfo(); 664 if (jump >= filler.addr_offset()) { 665 jump = filler.addr_offset(); 666 } else { // else shrink the filler to fit 667 filler = relocInfo(relocInfo::none, jump); 668 } 669 if (buf != NULL) { 670 assert(buf_offset + (csize_t)sizeof(filler) <= buf_limit, "filler in bounds"); 671 *(relocInfo*)(buf+buf_offset) = filler; 672 } 673 buf_offset += sizeof(filler); 674 } 675 676 // Update code point and end to skip past this section: 677 csize_t last_code_point = code_end_so_far + cs->locs_point_off(); 678 assert(code_point_so_far <= last_code_point, "sanity"); 679 code_point_so_far = last_code_point; // advance past this guy's relocs 680 } 681 code_end_so_far += csize; // advance past this guy's instructions too 682 683 // Done with filler; emit the real relocations: 684 if (buf != NULL && lsize != 0) { 685 assert(buf_offset + lsize <= buf_limit, "target in bounds"); 686 assert((uintptr_t)lstart % HeapWordSize == 0, "sane start"); 687 if (buf_offset % HeapWordSize == 0) { 688 // Use wordwise copies if possible: 689 Copy::disjoint_words((HeapWord*)lstart, 690 (HeapWord*)(buf+buf_offset), 691 (lsize + HeapWordSize-1) / HeapWordSize); 692 } else { 693 Copy::conjoint_jbytes(lstart, buf+buf_offset, lsize); 694 } 695 } 696 buf_offset += lsize; 697 } 698 699 // Align end of relocation info in target. 700 while (buf_offset % HeapWordSize != 0) { 701 if (buf != NULL) { 702 relocInfo padding = relocInfo(relocInfo::none, 0); 703 assert(buf_offset + (csize_t)sizeof(padding) <= buf_limit, "padding in bounds"); 704 *(relocInfo*)(buf+buf_offset) = padding; 705 } 706 buf_offset += sizeof(relocInfo); 707 } 708 709 assert(only_inst || code_end_so_far == total_content_size(), "sanity"); 710 711 return buf_offset; 712 } 713 714 csize_t CodeBuffer::copy_relocations_to(CodeBlob* dest) const { 715 address buf = NULL; 716 csize_t buf_offset = 0; 717 csize_t buf_limit = 0; 718 719 if (dest != NULL) { 720 buf = (address)dest->relocation_begin(); 721 buf_limit = (address)dest->relocation_end() - buf; 722 } 723 // if dest == NULL, this is just the sizing pass 724 // 725 buf_offset = copy_relocations_to(buf, buf_limit, false); 726 727 // Account for index: 728 if (buf != NULL) { 729 RelocIterator::create_index(dest->relocation_begin(), 730 buf_offset / sizeof(relocInfo), 731 dest->relocation_end()); 732 } 733 734 return buf_offset; 735 } 736 737 void CodeBuffer::copy_code_to(CodeBlob* dest_blob) { 738 #ifndef PRODUCT 739 if (PrintNMethods && (WizardMode || Verbose)) { 740 tty->print("done with CodeBuffer:"); 741 ((CodeBuffer*)this)->print(); 742 } 743 #endif //PRODUCT 744 745 CodeBuffer dest(dest_blob); 746 assert(dest_blob->content_size() >= total_content_size(), "good sizing"); 747 this->compute_final_layout(&dest); 748 relocate_code_to(&dest); 749 750 // transfer strings and comments from buffer to blob 751 dest_blob->set_strings(_code_strings); 752 753 // Done moving code bytes; were they the right size? 754 assert(round_to(dest.total_content_size(), oopSize) == dest_blob->content_size(), "sanity"); 755 756 // Flush generated code 757 ICache::invalidate_range(dest_blob->code_begin(), dest_blob->code_size()); 758 } 759 760 // Move all my code into another code buffer. Consult applicable 761 // relocs to repair embedded addresses. The layout in the destination 762 // CodeBuffer is different to the source CodeBuffer: the destination 763 // CodeBuffer gets the final layout (consts, insts, stubs in order of 764 // ascending address). 765 void CodeBuffer::relocate_code_to(CodeBuffer* dest) const { 766 address dest_end = dest->_total_start + dest->_total_size; 767 address dest_filled = NULL; 768 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 769 // pull code out of each section 770 const CodeSection* cs = code_section(n); 771 if (cs->is_empty()) continue; // skip trivial section 772 CodeSection* dest_cs = dest->code_section(n); 773 assert(cs->size() == dest_cs->size(), "sanity"); 774 csize_t usize = dest_cs->size(); 775 csize_t wsize = align_size_up(usize, HeapWordSize); 776 assert(dest_cs->start() + wsize <= dest_end, "no overflow"); 777 // Copy the code as aligned machine words. 778 // This may also include an uninitialized partial word at the end. 779 Copy::disjoint_words((HeapWord*)cs->start(), 780 (HeapWord*)dest_cs->start(), 781 wsize / HeapWordSize); 782 783 if (dest->blob() == NULL) { 784 // Destination is a final resting place, not just another buffer. 785 // Normalize uninitialized bytes in the final padding. 786 Copy::fill_to_bytes(dest_cs->end(), dest_cs->remaining(), 787 Assembler::code_fill_byte()); 788 } 789 // Keep track of the highest filled address 790 dest_filled = MAX2(dest_filled, dest_cs->end() + dest_cs->remaining()); 791 792 assert(cs->locs_start() != (relocInfo*)badAddress, 793 "this section carries no reloc storage, but reloc was attempted"); 794 795 // Make the new code copy use the old copy's relocations: 796 dest_cs->initialize_locs_from(cs); 797 } 798 799 // Do relocation after all sections are copied. 800 // This is necessary if the code uses constants in stubs, which are 801 // relocated when the corresponding instruction in the code (e.g., a 802 // call) is relocated. Stubs are placed behind the main code 803 // section, so that section has to be copied before relocating. 804 for (int n = (int) SECT_FIRST; n < (int)SECT_LIMIT; n++) { 805 // pull code out of each section 806 const CodeSection* cs = code_section(n); 807 if (cs->is_empty()) continue; // skip trivial section 808 CodeSection* dest_cs = dest->code_section(n); 809 { // Repair the pc relative information in the code after the move 810 RelocIterator iter(dest_cs); 811 while (iter.next()) { 812 iter.reloc()->fix_relocation_after_move(this, dest); 813 } 814 } 815 } 816 817 if (dest->blob() == NULL && dest_filled != NULL) { 818 // Destination is a final resting place, not just another buffer. 819 // Normalize uninitialized bytes in the final padding. 820 Copy::fill_to_bytes(dest_filled, dest_end - dest_filled, 821 Assembler::code_fill_byte()); 822 823 } 824 } 825 826 csize_t CodeBuffer::figure_expanded_capacities(CodeSection* which_cs, 827 csize_t amount, 828 csize_t* new_capacity) { 829 csize_t new_total_cap = 0; 830 831 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 832 const CodeSection* sect = code_section(n); 833 834 if (!sect->is_empty()) { 835 // Compute initial padding; assign it to the previous section, 836 // even if it's empty (e.g. consts section can be empty). 837 // Cf. compute_final_layout 838 csize_t padding = sect->align_at_start(new_total_cap) - new_total_cap; 839 if (padding != 0) { 840 new_total_cap += padding; 841 assert(n - 1 >= SECT_FIRST, "sanity"); 842 new_capacity[n - 1] += padding; 843 } 844 } 845 846 csize_t exp = sect->size(); // 100% increase 847 if ((uint)exp < 4*K) exp = 4*K; // minimum initial increase 848 if (sect == which_cs) { 849 if (exp < amount) exp = amount; 850 if (StressCodeBuffers) exp = amount; // expand only slightly 851 } else if (n == SECT_INSTS) { 852 // scale down inst increases to a more modest 25% 853 exp = 4*K + ((exp - 4*K) >> 2); 854 if (StressCodeBuffers) exp = amount / 2; // expand only slightly 855 } else if (sect->is_empty()) { 856 // do not grow an empty secondary section 857 exp = 0; 858 } 859 // Allow for inter-section slop: 860 exp += CodeSection::end_slop(); 861 csize_t new_cap = sect->size() + exp; 862 if (new_cap < sect->capacity()) { 863 // No need to expand after all. 864 new_cap = sect->capacity(); 865 } 866 new_capacity[n] = new_cap; 867 new_total_cap += new_cap; 868 } 869 870 return new_total_cap; 871 } 872 873 void CodeBuffer::expand(CodeSection* which_cs, csize_t amount) { 874 #ifndef PRODUCT 875 if (PrintNMethods && (WizardMode || Verbose)) { 876 tty->print("expanding CodeBuffer:"); 877 this->print(); 878 } 879 880 if (StressCodeBuffers && blob() != NULL) { 881 static int expand_count = 0; 882 if (expand_count >= 0) expand_count += 1; 883 if (expand_count > 100 && is_power_of_2(expand_count)) { 884 tty->print_cr("StressCodeBuffers: have expanded %d times", expand_count); 885 // simulate an occasional allocation failure: 886 free_blob(); 887 } 888 } 889 #endif //PRODUCT 890 891 // Resizing must be allowed 892 { 893 if (blob() == NULL) return; // caller must check for blob == NULL 894 for (int n = 0; n < (int)SECT_LIMIT; n++) { 895 guarantee(!code_section(n)->is_frozen(), "resizing not allowed when frozen"); 896 } 897 } 898 899 // Figure new capacity for each section. 900 csize_t new_capacity[SECT_LIMIT]; 901 memset(new_capacity, 0, sizeof(csize_t) * SECT_LIMIT); 902 csize_t new_total_cap 903 = figure_expanded_capacities(which_cs, amount, new_capacity); 904 905 // Create a new (temporary) code buffer to hold all the new data 906 CodeBuffer cb(name(), new_total_cap, 0); 907 if (cb.blob() == NULL) { 908 // Failed to allocate in code cache. 909 free_blob(); 910 return; 911 } 912 913 // Create an old code buffer to remember which addresses used to go where. 914 // This will be useful when we do final assembly into the code cache, 915 // because we will need to know how to warp any internal address that 916 // has been created at any time in this CodeBuffer's past. 917 CodeBuffer* bxp = new CodeBuffer(_total_start, _total_size); 918 bxp->take_over_code_from(this); // remember the old undersized blob 919 DEBUG_ONLY(this->_blob = NULL); // silence a later assert 920 bxp->_before_expand = this->_before_expand; 921 this->_before_expand = bxp; 922 923 // Give each section its required (expanded) capacity. 924 for (int n = (int)SECT_LIMIT-1; n >= SECT_FIRST; n--) { 925 CodeSection* cb_sect = cb.code_section(n); 926 CodeSection* this_sect = code_section(n); 927 if (new_capacity[n] == 0) continue; // already nulled out 928 if (n != SECT_INSTS) { 929 cb.initialize_section_size(cb_sect, new_capacity[n]); 930 } 931 assert(cb_sect->capacity() >= new_capacity[n], "big enough"); 932 address cb_start = cb_sect->start(); 933 cb_sect->set_end(cb_start + this_sect->size()); 934 if (this_sect->mark() == NULL) { 935 cb_sect->clear_mark(); 936 } else { 937 cb_sect->set_mark(cb_start + this_sect->mark_off()); 938 } 939 } 940 941 // Move all the code and relocations to the new blob: 942 relocate_code_to(&cb); 943 944 // Copy the temporary code buffer into the current code buffer. 945 // Basically, do {*this = cb}, except for some control information. 946 this->take_over_code_from(&cb); 947 cb.set_blob(NULL); 948 949 // Zap the old code buffer contents, to avoid mistakenly using them. 950 debug_only(Copy::fill_to_bytes(bxp->_total_start, bxp->_total_size, 951 badCodeHeapFreeVal)); 952 953 _decode_begin = NULL; // sanity 954 955 // Make certain that the new sections are all snugly inside the new blob. 956 verify_section_allocation(); 957 958 #ifndef PRODUCT 959 if (PrintNMethods && (WizardMode || Verbose)) { 960 tty->print("expanded CodeBuffer:"); 961 this->print(); 962 } 963 #endif //PRODUCT 964 } 965 966 void CodeBuffer::take_over_code_from(CodeBuffer* cb) { 967 // Must already have disposed of the old blob somehow. 968 assert(blob() == NULL, "must be empty"); 969 // Take the new blob away from cb. 970 set_blob(cb->blob()); 971 // Take over all the section pointers. 972 for (int n = 0; n < (int)SECT_LIMIT; n++) { 973 CodeSection* cb_sect = cb->code_section(n); 974 CodeSection* this_sect = code_section(n); 975 this_sect->take_over_code_from(cb_sect); 976 } 977 _overflow_arena = cb->_overflow_arena; 978 // Make sure the old cb won't try to use it or free it. 979 DEBUG_ONLY(cb->_blob = (BufferBlob*)badAddress); 980 } 981 982 void CodeBuffer::verify_section_allocation() { 983 address tstart = _total_start; 984 if (tstart == badAddress) return; // smashed by set_blob(NULL) 985 address tend = tstart + _total_size; 986 if (_blob != NULL) { 987 988 guarantee(tstart >= _blob->content_begin(), "sanity"); 989 guarantee(tend <= _blob->content_end(), "sanity"); 990 } 991 // Verify disjointness. 992 for (int n = (int) SECT_FIRST; n < (int) SECT_LIMIT; n++) { 993 CodeSection* sect = code_section(n); 994 if (!sect->is_allocated() || sect->is_empty()) continue; 995 guarantee((intptr_t)sect->start() % sect->alignment() == 0 996 || sect->is_empty() || _blob == NULL, 997 "start is aligned"); 998 for (int m = (int) SECT_FIRST; m < (int) SECT_LIMIT; m++) { 999 CodeSection* other = code_section(m); 1000 if (!other->is_allocated() || other == sect) continue; 1001 guarantee(!other->contains(sect->start() ), "sanity"); 1002 // limit is an exclusive address and can be the start of another 1003 // section. 1004 guarantee(!other->contains(sect->limit() - 1), "sanity"); 1005 } 1006 guarantee(sect->end() <= tend, "sanity"); 1007 guarantee(sect->end() <= sect->limit(), "sanity"); 1008 } 1009 } 1010 1011 void CodeBuffer::log_section_sizes(const char* name) { 1012 if (xtty != NULL) { 1013 ttyLocker ttyl; 1014 // log info about buffer usage 1015 xtty->print_cr("<blob name='%s' size='%d'>", name, _total_size); 1016 for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) { 1017 CodeSection* sect = code_section(n); 1018 if (!sect->is_allocated() || sect->is_empty()) continue; 1019 xtty->print_cr("<sect index='%d' size='" SIZE_FORMAT "' free='" SIZE_FORMAT "'/>", 1020 n, sect->limit() - sect->start(), sect->limit() - sect->end()); 1021 } 1022 xtty->print_cr("</blob>"); 1023 } 1024 } 1025 1026 #ifndef PRODUCT 1027 1028 void CodeSection::dump() { 1029 address ptr = start(); 1030 for (csize_t step; ptr < end(); ptr += step) { 1031 step = end() - ptr; 1032 if (step > jintSize * 4) step = jintSize * 4; 1033 tty->print(INTPTR_FORMAT ": ", p2i(ptr)); 1034 while (step > 0) { 1035 tty->print(" " PTR32_FORMAT, *(jint*)ptr); 1036 ptr += jintSize; 1037 } 1038 tty->cr(); 1039 } 1040 } 1041 1042 1043 void CodeSection::decode() { 1044 Disassembler::decode(start(), end()); 1045 } 1046 1047 1048 void CodeBuffer::block_comment(intptr_t offset, const char * comment) { 1049 _code_strings.add_comment(offset, comment); 1050 } 1051 1052 const char* CodeBuffer::code_string(const char* str) { 1053 return _code_strings.add_string(str); 1054 } 1055 1056 class CodeString: public CHeapObj<mtCode> { 1057 private: 1058 friend class CodeStrings; 1059 const char * _string; 1060 CodeString* _next; 1061 intptr_t _offset; 1062 1063 ~CodeString() { 1064 assert(_next == NULL, "wrong interface for freeing list"); 1065 os::free((void*)_string); 1066 } 1067 1068 bool is_comment() const { return _offset >= 0; } 1069 1070 public: 1071 CodeString(const char * string, intptr_t offset = -1) 1072 : _next(NULL), _offset(offset) { 1073 _string = os::strdup(string, mtCode); 1074 } 1075 1076 const char * string() const { return _string; } 1077 intptr_t offset() const { assert(_offset >= 0, "offset for non comment?"); return _offset; } 1078 CodeString* next() const { return _next; } 1079 1080 void set_next(CodeString* next) { _next = next; } 1081 1082 CodeString* first_comment() { 1083 if (is_comment()) { 1084 return this; 1085 } else { 1086 return next_comment(); 1087 } 1088 } 1089 CodeString* next_comment() const { 1090 CodeString* s = _next; 1091 while (s != NULL && !s->is_comment()) { 1092 s = s->_next; 1093 } 1094 return s; 1095 } 1096 }; 1097 1098 CodeString* CodeStrings::find(intptr_t offset) const { 1099 CodeString* a = _strings->first_comment(); 1100 while (a != NULL && a->offset() != offset) { 1101 a = a->next_comment(); 1102 } 1103 return a; 1104 } 1105 1106 // Convenience for add_comment. 1107 CodeString* CodeStrings::find_last(intptr_t offset) const { 1108 CodeString* a = find(offset); 1109 if (a != NULL) { 1110 CodeString* c = NULL; 1111 while (((c = a->next_comment()) != NULL) && (c->offset() == offset)) { 1112 a = c; 1113 } 1114 } 1115 return a; 1116 } 1117 1118 void CodeStrings::add_comment(intptr_t offset, const char * comment) { 1119 check_valid(); 1120 CodeString* c = new CodeString(comment, offset); 1121 CodeString* inspos = (_strings == NULL) ? NULL : find_last(offset); 1122 1123 if (inspos) { 1124 // insert after already existing comments with same offset 1125 c->set_next(inspos->next()); 1126 inspos->set_next(c); 1127 } else { 1128 // no comments with such offset, yet. Insert before anything else. 1129 c->set_next(_strings); 1130 _strings = c; 1131 } 1132 } 1133 1134 void CodeStrings::assign(CodeStrings& other) { 1135 other.check_valid(); 1136 assert(is_null(), "Cannot assign onto non-empty CodeStrings"); 1137 _strings = other._strings; 1138 #ifdef ASSERT 1139 _defunct = false; 1140 #endif 1141 other.set_null_and_invalidate(); 1142 } 1143 1144 // Deep copy of CodeStrings for consistent memory management. 1145 // Only used for actual disassembly so this is cheaper than reference counting 1146 // for the "normal" fastdebug case. 1147 void CodeStrings::copy(CodeStrings& other) { 1148 other.check_valid(); 1149 check_valid(); 1150 assert(is_null(), "Cannot copy onto non-empty CodeStrings"); 1151 CodeString* n = other._strings; 1152 CodeString** ps = &_strings; 1153 while (n != NULL) { 1154 *ps = new CodeString(n->string(),n->offset()); 1155 ps = &((*ps)->_next); 1156 n = n->next(); 1157 } 1158 } 1159 1160 const char* CodeStrings::_prefix = " ;; "; // default: can be changed via set_prefix 1161 1162 void CodeStrings::print_block_comment(outputStream* stream, intptr_t offset) const { 1163 check_valid(); 1164 if (_strings != NULL) { 1165 CodeString* c = find(offset); 1166 while (c && c->offset() == offset) { 1167 stream->bol(); 1168 stream->print("%s", _prefix); 1169 // Don't interpret as format strings since it could contain % 1170 stream->print_raw_cr(c->string()); 1171 c = c->next_comment(); 1172 } 1173 } 1174 } 1175 1176 // Also sets isNull() 1177 void CodeStrings::free() { 1178 CodeString* n = _strings; 1179 while (n) { 1180 // unlink the node from the list saving a pointer to the next 1181 CodeString* p = n->next(); 1182 n->set_next(NULL); 1183 delete n; 1184 n = p; 1185 } 1186 set_null_and_invalidate(); 1187 } 1188 1189 const char* CodeStrings::add_string(const char * string) { 1190 check_valid(); 1191 CodeString* s = new CodeString(string); 1192 s->set_next(_strings); 1193 _strings = s; 1194 assert(s->string() != NULL, "should have a string"); 1195 return s->string(); 1196 } 1197 1198 void CodeBuffer::decode() { 1199 ttyLocker ttyl; 1200 Disassembler::decode(decode_begin(), insts_end()); 1201 _decode_begin = insts_end(); 1202 } 1203 1204 1205 void CodeBuffer::skip_decode() { 1206 _decode_begin = insts_end(); 1207 } 1208 1209 1210 void CodeBuffer::decode_all() { 1211 ttyLocker ttyl; 1212 for (int n = 0; n < (int)SECT_LIMIT; n++) { 1213 // dump contents of each section 1214 CodeSection* cs = code_section(n); 1215 tty->print_cr("! %s:", code_section_name(n)); 1216 if (cs != consts()) 1217 cs->decode(); 1218 else 1219 cs->dump(); 1220 } 1221 } 1222 1223 1224 void CodeSection::print(const char* name) { 1225 csize_t locs_size = locs_end() - locs_start(); 1226 tty->print_cr(" %7s.code = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d)%s", 1227 name, p2i(start()), p2i(end()), p2i(limit()), size(), capacity(), 1228 is_frozen()? " [frozen]": ""); 1229 tty->print_cr(" %7s.locs = " PTR_FORMAT " : " PTR_FORMAT " : " PTR_FORMAT " (%d of %d) point=%d", 1230 name, p2i(locs_start()), p2i(locs_end()), p2i(locs_limit()), locs_size, locs_capacity(), locs_point_off()); 1231 if (PrintRelocations) { 1232 RelocIterator iter(this); 1233 iter.print(); 1234 } 1235 } 1236 1237 void CodeBuffer::print() { 1238 if (this == NULL) { 1239 tty->print_cr("NULL CodeBuffer pointer"); 1240 return; 1241 } 1242 1243 tty->print_cr("CodeBuffer:"); 1244 for (int n = 0; n < (int)SECT_LIMIT; n++) { 1245 // print each section 1246 CodeSection* cs = code_section(n); 1247 cs->print(code_section_name(n)); 1248 } 1249 } 1250 1251 #endif // PRODUCT