| 1 | // layout.cc -- lay out output file sections for gold |
| 2 | |
| 3 | // Copyright (C) 2006-2018 Free Software Foundation, Inc. |
| 4 | // Written by Ian Lance Taylor <iant@google.com>. |
| 5 | |
| 6 | // This file is part of gold. |
| 7 | |
| 8 | // This program is free software; you can redistribute it and/or modify |
| 9 | // it under the terms of the GNU General Public License as published by |
| 10 | // the Free Software Foundation; either version 3 of the License, or |
| 11 | // (at your option) any later version. |
| 12 | |
| 13 | // This program is distributed in the hope that it will be useful, |
| 14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | // GNU General Public License for more details. |
| 17 | |
| 18 | // You should have received a copy of the GNU General Public License |
| 19 | // along with this program; if not, write to the Free Software |
| 20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 21 | // MA 02110-1301, USA. |
| 22 | |
| 23 | #include "gold.h" |
| 24 | |
| 25 | #include <cerrno> |
| 26 | #include <cstring> |
| 27 | #include <algorithm> |
| 28 | #include <iostream> |
| 29 | #include <fstream> |
| 30 | #include <utility> |
| 31 | #include <fcntl.h> |
| 32 | #include <fnmatch.h> |
| 33 | #include <unistd.h> |
| 34 | #include "libiberty.h" |
| 35 | #include "md5.h" |
| 36 | #include "sha1.h" |
| 37 | #ifdef __MINGW32__ |
| 38 | #include <windows.h> |
| 39 | #include <rpcdce.h> |
| 40 | #endif |
| 41 | |
| 42 | #include "parameters.h" |
| 43 | #include "options.h" |
| 44 | #include "mapfile.h" |
| 45 | #include "script.h" |
| 46 | #include "script-sections.h" |
| 47 | #include "output.h" |
| 48 | #include "symtab.h" |
| 49 | #include "dynobj.h" |
| 50 | #include "ehframe.h" |
| 51 | #include "gdb-index.h" |
| 52 | #include "compressed_output.h" |
| 53 | #include "reduced_debug_output.h" |
| 54 | #include "object.h" |
| 55 | #include "reloc.h" |
| 56 | #include "descriptors.h" |
| 57 | #include "plugin.h" |
| 58 | #include "incremental.h" |
| 59 | #include "layout.h" |
| 60 | |
| 61 | namespace gold |
| 62 | { |
| 63 | |
| 64 | // Class Free_list. |
| 65 | |
| 66 | // The total number of free lists used. |
| 67 | unsigned int Free_list::num_lists = 0; |
| 68 | // The total number of free list nodes used. |
| 69 | unsigned int Free_list::num_nodes = 0; |
| 70 | // The total number of calls to Free_list::remove. |
| 71 | unsigned int Free_list::num_removes = 0; |
| 72 | // The total number of nodes visited during calls to Free_list::remove. |
| 73 | unsigned int Free_list::num_remove_visits = 0; |
| 74 | // The total number of calls to Free_list::allocate. |
| 75 | unsigned int Free_list::num_allocates = 0; |
| 76 | // The total number of nodes visited during calls to Free_list::allocate. |
| 77 | unsigned int Free_list::num_allocate_visits = 0; |
| 78 | |
| 79 | // Initialize the free list. Creates a single free list node that |
| 80 | // describes the entire region of length LEN. If EXTEND is true, |
| 81 | // allocate() is allowed to extend the region beyond its initial |
| 82 | // length. |
| 83 | |
| 84 | void |
| 85 | Free_list::init(off_t len, bool extend) |
| 86 | { |
| 87 | this->list_.push_front(Free_list_node(0, len)); |
| 88 | this->last_remove_ = this->list_.begin(); |
| 89 | this->extend_ = extend; |
| 90 | this->length_ = len; |
| 91 | ++Free_list::num_lists; |
| 92 | ++Free_list::num_nodes; |
| 93 | } |
| 94 | |
| 95 | // Remove a chunk from the free list. Because we start with a single |
| 96 | // node that covers the entire section, and remove chunks from it one |
| 97 | // at a time, we do not need to coalesce chunks or handle cases that |
| 98 | // span more than one free node. We expect to remove chunks from the |
| 99 | // free list in order, and we expect to have only a few chunks of free |
| 100 | // space left (corresponding to files that have changed since the last |
| 101 | // incremental link), so a simple linear list should provide sufficient |
| 102 | // performance. |
| 103 | |
| 104 | void |
| 105 | Free_list::remove(off_t start, off_t end) |
| 106 | { |
| 107 | if (start == end) |
| 108 | return; |
| 109 | gold_assert(start < end); |
| 110 | |
| 111 | ++Free_list::num_removes; |
| 112 | |
| 113 | Iterator p = this->last_remove_; |
| 114 | if (p->start_ > start) |
| 115 | p = this->list_.begin(); |
| 116 | |
| 117 | for (; p != this->list_.end(); ++p) |
| 118 | { |
| 119 | ++Free_list::num_remove_visits; |
| 120 | // Find a node that wholly contains the indicated region. |
| 121 | if (p->start_ <= start && p->end_ >= end) |
| 122 | { |
| 123 | // Case 1: the indicated region spans the whole node. |
| 124 | // Add some fuzz to avoid creating tiny free chunks. |
| 125 | if (p->start_ + 3 >= start && p->end_ <= end + 3) |
| 126 | p = this->list_.erase(p); |
| 127 | // Case 2: remove a chunk from the start of the node. |
| 128 | else if (p->start_ + 3 >= start) |
| 129 | p->start_ = end; |
| 130 | // Case 3: remove a chunk from the end of the node. |
| 131 | else if (p->end_ <= end + 3) |
| 132 | p->end_ = start; |
| 133 | // Case 4: remove a chunk from the middle, and split |
| 134 | // the node into two. |
| 135 | else |
| 136 | { |
| 137 | Free_list_node newnode(p->start_, start); |
| 138 | p->start_ = end; |
| 139 | this->list_.insert(p, newnode); |
| 140 | ++Free_list::num_nodes; |
| 141 | } |
| 142 | this->last_remove_ = p; |
| 143 | return; |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | // Did not find a node containing the given chunk. This could happen |
| 148 | // because a small chunk was already removed due to the fuzz. |
| 149 | gold_debug(DEBUG_INCREMENTAL, |
| 150 | "Free_list::remove(%d,%d) not found", |
| 151 | static_cast<int>(start), static_cast<int>(end)); |
| 152 | } |
| 153 | |
| 154 | // Allocate a chunk of size LEN from the free list. Returns -1ULL |
| 155 | // if a sufficiently large chunk of free space is not found. |
| 156 | // We use a simple first-fit algorithm. |
| 157 | |
| 158 | off_t |
| 159 | Free_list::allocate(off_t len, uint64_t align, off_t minoff) |
| 160 | { |
| 161 | gold_debug(DEBUG_INCREMENTAL, |
| 162 | "Free_list::allocate(%08lx, %d, %08lx)", |
| 163 | static_cast<long>(len), static_cast<int>(align), |
| 164 | static_cast<long>(minoff)); |
| 165 | if (len == 0) |
| 166 | return align_address(minoff, align); |
| 167 | |
| 168 | ++Free_list::num_allocates; |
| 169 | |
| 170 | // We usually want to drop free chunks smaller than 4 bytes. |
| 171 | // If we need to guarantee a minimum hole size, though, we need |
| 172 | // to keep track of all free chunks. |
| 173 | const int fuzz = this->min_hole_ > 0 ? 0 : 3; |
| 174 | |
| 175 | for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p) |
| 176 | { |
| 177 | ++Free_list::num_allocate_visits; |
| 178 | off_t start = p->start_ > minoff ? p->start_ : minoff; |
| 179 | start = align_address(start, align); |
| 180 | off_t end = start + len; |
| 181 | if (end > p->end_ && p->end_ == this->length_ && this->extend_) |
| 182 | { |
| 183 | this->length_ = end; |
| 184 | p->end_ = end; |
| 185 | } |
| 186 | if (end == p->end_ || (end <= p->end_ - this->min_hole_)) |
| 187 | { |
| 188 | if (p->start_ + fuzz >= start && p->end_ <= end + fuzz) |
| 189 | this->list_.erase(p); |
| 190 | else if (p->start_ + fuzz >= start) |
| 191 | p->start_ = end; |
| 192 | else if (p->end_ <= end + fuzz) |
| 193 | p->end_ = start; |
| 194 | else |
| 195 | { |
| 196 | Free_list_node newnode(p->start_, start); |
| 197 | p->start_ = end; |
| 198 | this->list_.insert(p, newnode); |
| 199 | ++Free_list::num_nodes; |
| 200 | } |
| 201 | return start; |
| 202 | } |
| 203 | } |
| 204 | if (this->extend_) |
| 205 | { |
| 206 | off_t start = align_address(this->length_, align); |
| 207 | this->length_ = start + len; |
| 208 | return start; |
| 209 | } |
| 210 | return -1; |
| 211 | } |
| 212 | |
| 213 | // Dump the free list (for debugging). |
| 214 | void |
| 215 | Free_list::dump() |
| 216 | { |
| 217 | gold_info("Free list:\n start end length\n"); |
| 218 | for (Iterator p = this->list_.begin(); p != this->list_.end(); ++p) |
| 219 | gold_info(" %08lx %08lx %08lx", static_cast<long>(p->start_), |
| 220 | static_cast<long>(p->end_), |
| 221 | static_cast<long>(p->end_ - p->start_)); |
| 222 | } |
| 223 | |
| 224 | // Print the statistics for the free lists. |
| 225 | void |
| 226 | Free_list::print_stats() |
| 227 | { |
| 228 | fprintf(stderr, _("%s: total free lists: %u\n"), |
| 229 | program_name, Free_list::num_lists); |
| 230 | fprintf(stderr, _("%s: total free list nodes: %u\n"), |
| 231 | program_name, Free_list::num_nodes); |
| 232 | fprintf(stderr, _("%s: calls to Free_list::remove: %u\n"), |
| 233 | program_name, Free_list::num_removes); |
| 234 | fprintf(stderr, _("%s: nodes visited: %u\n"), |
| 235 | program_name, Free_list::num_remove_visits); |
| 236 | fprintf(stderr, _("%s: calls to Free_list::allocate: %u\n"), |
| 237 | program_name, Free_list::num_allocates); |
| 238 | fprintf(stderr, _("%s: nodes visited: %u\n"), |
| 239 | program_name, Free_list::num_allocate_visits); |
| 240 | } |
| 241 | |
| 242 | // A Hash_task computes the MD5 checksum of an array of char. |
| 243 | |
| 244 | class Hash_task : public Task |
| 245 | { |
| 246 | public: |
| 247 | Hash_task(Output_file* of, |
| 248 | size_t offset, |
| 249 | size_t size, |
| 250 | unsigned char* dst, |
| 251 | Task_token* final_blocker) |
| 252 | : of_(of), offset_(offset), size_(size), dst_(dst), |
| 253 | final_blocker_(final_blocker) |
| 254 | { } |
| 255 | |
| 256 | void |
| 257 | run(Workqueue*) |
| 258 | { |
| 259 | const unsigned char* iv = |
| 260 | this->of_->get_input_view(this->offset_, this->size_); |
| 261 | md5_buffer(reinterpret_cast<const char*>(iv), this->size_, this->dst_); |
| 262 | this->of_->free_input_view(this->offset_, this->size_, iv); |
| 263 | } |
| 264 | |
| 265 | Task_token* |
| 266 | is_runnable() |
| 267 | { return NULL; } |
| 268 | |
| 269 | // Unblock FINAL_BLOCKER_ when done. |
| 270 | void |
| 271 | locks(Task_locker* tl) |
| 272 | { tl->add(this, this->final_blocker_); } |
| 273 | |
| 274 | std::string |
| 275 | get_name() const |
| 276 | { return "Hash_task"; } |
| 277 | |
| 278 | private: |
| 279 | Output_file* of_; |
| 280 | const size_t offset_; |
| 281 | const size_t size_; |
| 282 | unsigned char* const dst_; |
| 283 | Task_token* const final_blocker_; |
| 284 | }; |
| 285 | |
| 286 | // Layout::Relaxation_debug_check methods. |
| 287 | |
| 288 | // Check that sections and special data are in reset states. |
| 289 | // We do not save states for Output_sections and special Output_data. |
| 290 | // So we check that they have not assigned any addresses or offsets. |
| 291 | // clean_up_after_relaxation simply resets their addresses and offsets. |
| 292 | void |
| 293 | Layout::Relaxation_debug_check::check_output_data_for_reset_values( |
| 294 | const Layout::Section_list& sections, |
| 295 | const Layout::Data_list& special_outputs, |
| 296 | const Layout::Data_list& relax_outputs) |
| 297 | { |
| 298 | for(Layout::Section_list::const_iterator p = sections.begin(); |
| 299 | p != sections.end(); |
| 300 | ++p) |
| 301 | gold_assert((*p)->address_and_file_offset_have_reset_values()); |
| 302 | |
| 303 | for(Layout::Data_list::const_iterator p = special_outputs.begin(); |
| 304 | p != special_outputs.end(); |
| 305 | ++p) |
| 306 | gold_assert((*p)->address_and_file_offset_have_reset_values()); |
| 307 | |
| 308 | gold_assert(relax_outputs.empty()); |
| 309 | } |
| 310 | |
| 311 | // Save information of SECTIONS for checking later. |
| 312 | |
| 313 | void |
| 314 | Layout::Relaxation_debug_check::read_sections( |
| 315 | const Layout::Section_list& sections) |
| 316 | { |
| 317 | for(Layout::Section_list::const_iterator p = sections.begin(); |
| 318 | p != sections.end(); |
| 319 | ++p) |
| 320 | { |
| 321 | Output_section* os = *p; |
| 322 | Section_info info; |
| 323 | info.output_section = os; |
| 324 | info.address = os->is_address_valid() ? os->address() : 0; |
| 325 | info.data_size = os->is_data_size_valid() ? os->data_size() : -1; |
| 326 | info.offset = os->is_offset_valid()? os->offset() : -1 ; |
| 327 | this->section_infos_.push_back(info); |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | // Verify SECTIONS using previously recorded information. |
| 332 | |
| 333 | void |
| 334 | Layout::Relaxation_debug_check::verify_sections( |
| 335 | const Layout::Section_list& sections) |
| 336 | { |
| 337 | size_t i = 0; |
| 338 | for(Layout::Section_list::const_iterator p = sections.begin(); |
| 339 | p != sections.end(); |
| 340 | ++p, ++i) |
| 341 | { |
| 342 | Output_section* os = *p; |
| 343 | uint64_t address = os->is_address_valid() ? os->address() : 0; |
| 344 | off_t data_size = os->is_data_size_valid() ? os->data_size() : -1; |
| 345 | off_t offset = os->is_offset_valid()? os->offset() : -1 ; |
| 346 | |
| 347 | if (i >= this->section_infos_.size()) |
| 348 | { |
| 349 | gold_fatal("Section_info of %s missing.\n", os->name()); |
| 350 | } |
| 351 | const Section_info& info = this->section_infos_[i]; |
| 352 | if (os != info.output_section) |
| 353 | gold_fatal("Section order changed. Expecting %s but see %s\n", |
| 354 | info.output_section->name(), os->name()); |
| 355 | if (address != info.address |
| 356 | || data_size != info.data_size |
| 357 | || offset != info.offset) |
| 358 | gold_fatal("Section %s changed.\n", os->name()); |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | // Layout_task_runner methods. |
| 363 | |
| 364 | // Lay out the sections. This is called after all the input objects |
| 365 | // have been read. |
| 366 | |
| 367 | void |
| 368 | Layout_task_runner::run(Workqueue* workqueue, const Task* task) |
| 369 | { |
| 370 | // See if any of the input definitions violate the One Definition Rule. |
| 371 | // TODO: if this is too slow, do this as a task, rather than inline. |
| 372 | this->symtab_->detect_odr_violations(task, this->options_.output_file_name()); |
| 373 | |
| 374 | Layout* layout = this->layout_; |
| 375 | off_t file_size = layout->finalize(this->input_objects_, |
| 376 | this->symtab_, |
| 377 | this->target_, |
| 378 | task); |
| 379 | |
| 380 | // Now we know the final size of the output file and we know where |
| 381 | // each piece of information goes. |
| 382 | |
| 383 | if (this->mapfile_ != NULL) |
| 384 | { |
| 385 | this->mapfile_->print_discarded_sections(this->input_objects_); |
| 386 | layout->print_to_mapfile(this->mapfile_); |
| 387 | } |
| 388 | |
| 389 | Output_file* of; |
| 390 | if (layout->incremental_base() == NULL) |
| 391 | { |
| 392 | of = new Output_file(parameters->options().output_file_name()); |
| 393 | if (this->options_.oformat_enum() != General_options::OBJECT_FORMAT_ELF) |
| 394 | of->set_is_temporary(); |
| 395 | of->open(file_size); |
| 396 | } |
| 397 | else |
| 398 | { |
| 399 | of = layout->incremental_base()->output_file(); |
| 400 | |
| 401 | // Apply the incremental relocations for symbols whose values |
| 402 | // have changed. We do this before we resize the file and start |
| 403 | // writing anything else to it, so that we can read the old |
| 404 | // incremental information from the file before (possibly) |
| 405 | // overwriting it. |
| 406 | if (parameters->incremental_update()) |
| 407 | layout->incremental_base()->apply_incremental_relocs(this->symtab_, |
| 408 | this->layout_, |
| 409 | of); |
| 410 | |
| 411 | of->resize(file_size); |
| 412 | } |
| 413 | |
| 414 | // Queue up the final set of tasks. |
| 415 | gold::queue_final_tasks(this->options_, this->input_objects_, |
| 416 | this->symtab_, layout, workqueue, of); |
| 417 | } |
| 418 | |
| 419 | // Layout methods. |
| 420 | |
| 421 | Layout::Layout(int number_of_input_files, Script_options* script_options) |
| 422 | : number_of_input_files_(number_of_input_files), |
| 423 | script_options_(script_options), |
| 424 | namepool_(), |
| 425 | sympool_(), |
| 426 | dynpool_(), |
| 427 | signatures_(), |
| 428 | section_name_map_(), |
| 429 | segment_list_(), |
| 430 | section_list_(), |
| 431 | unattached_section_list_(), |
| 432 | special_output_list_(), |
| 433 | relax_output_list_(), |
| 434 | section_headers_(NULL), |
| 435 | tls_segment_(NULL), |
| 436 | relro_segment_(NULL), |
| 437 | interp_segment_(NULL), |
| 438 | increase_relro_(0), |
| 439 | symtab_section_(NULL), |
| 440 | symtab_xindex_(NULL), |
| 441 | dynsym_section_(NULL), |
| 442 | dynsym_xindex_(NULL), |
| 443 | dynamic_section_(NULL), |
| 444 | dynamic_symbol_(NULL), |
| 445 | dynamic_data_(NULL), |
| 446 | eh_frame_section_(NULL), |
| 447 | eh_frame_data_(NULL), |
| 448 | added_eh_frame_data_(false), |
| 449 | eh_frame_hdr_section_(NULL), |
| 450 | gdb_index_data_(NULL), |
| 451 | build_id_note_(NULL), |
| 452 | debug_abbrev_(NULL), |
| 453 | debug_info_(NULL), |
| 454 | group_signatures_(), |
| 455 | output_file_size_(-1), |
| 456 | have_added_input_section_(false), |
| 457 | sections_are_attached_(false), |
| 458 | input_requires_executable_stack_(false), |
| 459 | input_with_gnu_stack_note_(false), |
| 460 | input_without_gnu_stack_note_(false), |
| 461 | has_static_tls_(false), |
| 462 | any_postprocessing_sections_(false), |
| 463 | resized_signatures_(false), |
| 464 | have_stabstr_section_(false), |
| 465 | section_ordering_specified_(false), |
| 466 | unique_segment_for_sections_specified_(false), |
| 467 | incremental_inputs_(NULL), |
| 468 | record_output_section_data_from_script_(false), |
| 469 | script_output_section_data_list_(), |
| 470 | segment_states_(NULL), |
| 471 | relaxation_debug_check_(NULL), |
| 472 | section_order_map_(), |
| 473 | section_segment_map_(), |
| 474 | input_section_position_(), |
| 475 | input_section_glob_(), |
| 476 | incremental_base_(NULL), |
| 477 | free_list_() |
| 478 | { |
| 479 | // Make space for more than enough segments for a typical file. |
| 480 | // This is just for efficiency--it's OK if we wind up needing more. |
| 481 | this->segment_list_.reserve(12); |
| 482 | |
| 483 | // We expect two unattached Output_data objects: the file header and |
| 484 | // the segment headers. |
| 485 | this->special_output_list_.reserve(2); |
| 486 | |
| 487 | // Initialize structure needed for an incremental build. |
| 488 | if (parameters->incremental()) |
| 489 | this->incremental_inputs_ = new Incremental_inputs; |
| 490 | |
| 491 | // The section name pool is worth optimizing in all cases, because |
| 492 | // it is small, but there are often overlaps due to .rel sections. |
| 493 | this->namepool_.set_optimize(); |
| 494 | } |
| 495 | |
| 496 | // For incremental links, record the base file to be modified. |
| 497 | |
| 498 | void |
| 499 | Layout::set_incremental_base(Incremental_binary* base) |
| 500 | { |
| 501 | this->incremental_base_ = base; |
| 502 | this->free_list_.init(base->output_file()->filesize(), true); |
| 503 | } |
| 504 | |
| 505 | // Hash a key we use to look up an output section mapping. |
| 506 | |
| 507 | size_t |
| 508 | Layout::Hash_key::operator()(const Layout::Key& k) const |
| 509 | { |
| 510 | return k.first + k.second.first + k.second.second; |
| 511 | } |
| 512 | |
| 513 | // These are the debug sections that are actually used by gdb. |
| 514 | // Currently, we've checked versions of gdb up to and including 7.4. |
| 515 | // We only check the part of the name that follows ".debug_" or |
| 516 | // ".zdebug_". |
| 517 | |
| 518 | static const char* gdb_sections[] = |
| 519 | { |
| 520 | "abbrev", |
| 521 | "addr", // Fission extension |
| 522 | // "aranges", // not used by gdb as of 7.4 |
| 523 | "frame", |
| 524 | "gdb_scripts", |
| 525 | "info", |
| 526 | "types", |
| 527 | "line", |
| 528 | "loc", |
| 529 | "macinfo", |
| 530 | "macro", |
| 531 | // "pubnames", // not used by gdb as of 7.4 |
| 532 | // "pubtypes", // not used by gdb as of 7.4 |
| 533 | // "gnu_pubnames", // Fission extension |
| 534 | // "gnu_pubtypes", // Fission extension |
| 535 | "ranges", |
| 536 | "str", |
| 537 | "str_offsets", |
| 538 | }; |
| 539 | |
| 540 | // This is the minimum set of sections needed for line numbers. |
| 541 | |
| 542 | static const char* lines_only_debug_sections[] = |
| 543 | { |
| 544 | "abbrev", |
| 545 | // "addr", // Fission extension |
| 546 | // "aranges", // not used by gdb as of 7.4 |
| 547 | // "frame", |
| 548 | // "gdb_scripts", |
| 549 | "info", |
| 550 | // "types", |
| 551 | "line", |
| 552 | // "loc", |
| 553 | // "macinfo", |
| 554 | // "macro", |
| 555 | // "pubnames", // not used by gdb as of 7.4 |
| 556 | // "pubtypes", // not used by gdb as of 7.4 |
| 557 | // "gnu_pubnames", // Fission extension |
| 558 | // "gnu_pubtypes", // Fission extension |
| 559 | // "ranges", |
| 560 | "str", |
| 561 | "str_offsets", // Fission extension |
| 562 | }; |
| 563 | |
| 564 | // These sections are the DWARF fast-lookup tables, and are not needed |
| 565 | // when building a .gdb_index section. |
| 566 | |
| 567 | static const char* gdb_fast_lookup_sections[] = |
| 568 | { |
| 569 | "aranges", |
| 570 | "pubnames", |
| 571 | "gnu_pubnames", |
| 572 | "pubtypes", |
| 573 | "gnu_pubtypes", |
| 574 | }; |
| 575 | |
| 576 | // Returns whether the given debug section is in the list of |
| 577 | // debug-sections-used-by-some-version-of-gdb. SUFFIX is the |
| 578 | // portion of the name following ".debug_" or ".zdebug_". |
| 579 | |
| 580 | static inline bool |
| 581 | is_gdb_debug_section(const char* suffix) |
| 582 | { |
| 583 | // We can do this faster: binary search or a hashtable. But why bother? |
| 584 | for (size_t i = 0; i < sizeof(gdb_sections)/sizeof(*gdb_sections); ++i) |
| 585 | if (strcmp(suffix, gdb_sections[i]) == 0) |
| 586 | return true; |
| 587 | return false; |
| 588 | } |
| 589 | |
| 590 | // Returns whether the given section is needed for lines-only debugging. |
| 591 | |
| 592 | static inline bool |
| 593 | is_lines_only_debug_section(const char* suffix) |
| 594 | { |
| 595 | // We can do this faster: binary search or a hashtable. But why bother? |
| 596 | for (size_t i = 0; |
| 597 | i < sizeof(lines_only_debug_sections)/sizeof(*lines_only_debug_sections); |
| 598 | ++i) |
| 599 | if (strcmp(suffix, lines_only_debug_sections[i]) == 0) |
| 600 | return true; |
| 601 | return false; |
| 602 | } |
| 603 | |
| 604 | // Returns whether the given section is a fast-lookup section that |
| 605 | // will not be needed when building a .gdb_index section. |
| 606 | |
| 607 | static inline bool |
| 608 | is_gdb_fast_lookup_section(const char* suffix) |
| 609 | { |
| 610 | // We can do this faster: binary search or a hashtable. But why bother? |
| 611 | for (size_t i = 0; |
| 612 | i < sizeof(gdb_fast_lookup_sections)/sizeof(*gdb_fast_lookup_sections); |
| 613 | ++i) |
| 614 | if (strcmp(suffix, gdb_fast_lookup_sections[i]) == 0) |
| 615 | return true; |
| 616 | return false; |
| 617 | } |
| 618 | |
| 619 | // Sometimes we compress sections. This is typically done for |
| 620 | // sections that are not part of normal program execution (such as |
| 621 | // .debug_* sections), and where the readers of these sections know |
| 622 | // how to deal with compressed sections. This routine doesn't say for |
| 623 | // certain whether we'll compress -- it depends on commandline options |
| 624 | // as well -- just whether this section is a candidate for compression. |
| 625 | // (The Output_compressed_section class decides whether to compress |
| 626 | // a given section, and picks the name of the compressed section.) |
| 627 | |
| 628 | static bool |
| 629 | is_compressible_debug_section(const char* secname) |
| 630 | { |
| 631 | return (is_prefix_of(".debug", secname)); |
| 632 | } |
| 633 | |
| 634 | // We may see compressed debug sections in input files. Return TRUE |
| 635 | // if this is the name of a compressed debug section. |
| 636 | |
| 637 | bool |
| 638 | is_compressed_debug_section(const char* secname) |
| 639 | { |
| 640 | return (is_prefix_of(".zdebug", secname)); |
| 641 | } |
| 642 | |
| 643 | std::string |
| 644 | corresponding_uncompressed_section_name(std::string secname) |
| 645 | { |
| 646 | gold_assert(secname[0] == '.' && secname[1] == 'z'); |
| 647 | std::string ret("."); |
| 648 | ret.append(secname, 2, std::string::npos); |
| 649 | return ret; |
| 650 | } |
| 651 | |
| 652 | // Whether to include this section in the link. |
| 653 | |
| 654 | template<int size, bool big_endian> |
| 655 | bool |
| 656 | Layout::include_section(Sized_relobj_file<size, big_endian>*, const char* name, |
| 657 | const elfcpp::Shdr<size, big_endian>& shdr) |
| 658 | { |
| 659 | if (!parameters->options().relocatable() |
| 660 | && (shdr.get_sh_flags() & elfcpp::SHF_EXCLUDE)) |
| 661 | return false; |
| 662 | |
| 663 | elfcpp::Elf_Word sh_type = shdr.get_sh_type(); |
| 664 | |
| 665 | if ((sh_type >= elfcpp::SHT_LOOS && sh_type <= elfcpp::SHT_HIOS) |
| 666 | || (sh_type >= elfcpp::SHT_LOPROC && sh_type <= elfcpp::SHT_HIPROC)) |
| 667 | return parameters->target().should_include_section(sh_type); |
| 668 | |
| 669 | switch (sh_type) |
| 670 | { |
| 671 | case elfcpp::SHT_NULL: |
| 672 | case elfcpp::SHT_SYMTAB: |
| 673 | case elfcpp::SHT_DYNSYM: |
| 674 | case elfcpp::SHT_HASH: |
| 675 | case elfcpp::SHT_DYNAMIC: |
| 676 | case elfcpp::SHT_SYMTAB_SHNDX: |
| 677 | return false; |
| 678 | |
| 679 | case elfcpp::SHT_STRTAB: |
| 680 | // Discard the sections which have special meanings in the ELF |
| 681 | // ABI. Keep others (e.g., .stabstr). We could also do this by |
| 682 | // checking the sh_link fields of the appropriate sections. |
| 683 | return (strcmp(name, ".dynstr") != 0 |
| 684 | && strcmp(name, ".strtab") != 0 |
| 685 | && strcmp(name, ".shstrtab") != 0); |
| 686 | |
| 687 | case elfcpp::SHT_RELA: |
| 688 | case elfcpp::SHT_REL: |
| 689 | case elfcpp::SHT_GROUP: |
| 690 | // If we are emitting relocations these should be handled |
| 691 | // elsewhere. |
| 692 | gold_assert(!parameters->options().relocatable()); |
| 693 | return false; |
| 694 | |
| 695 | case elfcpp::SHT_PROGBITS: |
| 696 | if (parameters->options().strip_debug() |
| 697 | && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) |
| 698 | { |
| 699 | if (is_debug_info_section(name)) |
| 700 | return false; |
| 701 | } |
| 702 | if (parameters->options().strip_debug_non_line() |
| 703 | && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) |
| 704 | { |
| 705 | // Debugging sections can only be recognized by name. |
| 706 | if (is_prefix_of(".debug_", name) |
| 707 | && !is_lines_only_debug_section(name + 7)) |
| 708 | return false; |
| 709 | if (is_prefix_of(".zdebug_", name) |
| 710 | && !is_lines_only_debug_section(name + 8)) |
| 711 | return false; |
| 712 | } |
| 713 | if (parameters->options().strip_debug_gdb() |
| 714 | && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) |
| 715 | { |
| 716 | // Debugging sections can only be recognized by name. |
| 717 | if (is_prefix_of(".debug_", name) |
| 718 | && !is_gdb_debug_section(name + 7)) |
| 719 | return false; |
| 720 | if (is_prefix_of(".zdebug_", name) |
| 721 | && !is_gdb_debug_section(name + 8)) |
| 722 | return false; |
| 723 | } |
| 724 | if (parameters->options().gdb_index() |
| 725 | && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) |
| 726 | { |
| 727 | // When building .gdb_index, we can strip .debug_pubnames, |
| 728 | // .debug_pubtypes, and .debug_aranges sections. |
| 729 | if (is_prefix_of(".debug_", name) |
| 730 | && is_gdb_fast_lookup_section(name + 7)) |
| 731 | return false; |
| 732 | if (is_prefix_of(".zdebug_", name) |
| 733 | && is_gdb_fast_lookup_section(name + 8)) |
| 734 | return false; |
| 735 | } |
| 736 | if (parameters->options().strip_lto_sections() |
| 737 | && !parameters->options().relocatable() |
| 738 | && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0) |
| 739 | { |
| 740 | // Ignore LTO sections containing intermediate code. |
| 741 | if (is_prefix_of(".gnu.lto_", name)) |
| 742 | return false; |
| 743 | } |
| 744 | // The GNU linker strips .gnu_debuglink sections, so we do too. |
| 745 | // This is a feature used to keep debugging information in |
| 746 | // separate files. |
| 747 | if (strcmp(name, ".gnu_debuglink") == 0) |
| 748 | return false; |
| 749 | return true; |
| 750 | |
| 751 | default: |
| 752 | return true; |
| 753 | } |
| 754 | } |
| 755 | |
| 756 | // Return an output section named NAME, or NULL if there is none. |
| 757 | |
| 758 | Output_section* |
| 759 | Layout::find_output_section(const char* name) const |
| 760 | { |
| 761 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 762 | p != this->section_list_.end(); |
| 763 | ++p) |
| 764 | if (strcmp((*p)->name(), name) == 0) |
| 765 | return *p; |
| 766 | return NULL; |
| 767 | } |
| 768 | |
| 769 | // Return an output segment of type TYPE, with segment flags SET set |
| 770 | // and segment flags CLEAR clear. Return NULL if there is none. |
| 771 | |
| 772 | Output_segment* |
| 773 | Layout::find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, |
| 774 | elfcpp::Elf_Word clear) const |
| 775 | { |
| 776 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 777 | p != this->segment_list_.end(); |
| 778 | ++p) |
| 779 | if (static_cast<elfcpp::PT>((*p)->type()) == type |
| 780 | && ((*p)->flags() & set) == set |
| 781 | && ((*p)->flags() & clear) == 0) |
| 782 | return *p; |
| 783 | return NULL; |
| 784 | } |
| 785 | |
| 786 | // When we put a .ctors or .dtors section with more than one word into |
| 787 | // a .init_array or .fini_array section, we need to reverse the words |
| 788 | // in the .ctors/.dtors section. This is because .init_array executes |
| 789 | // constructors front to back, where .ctors executes them back to |
| 790 | // front, and vice-versa for .fini_array/.dtors. Although we do want |
| 791 | // to remap .ctors/.dtors into .init_array/.fini_array because it can |
| 792 | // be more efficient, we don't want to change the order in which |
| 793 | // constructors/destructors are run. This set just keeps track of |
| 794 | // these sections which need to be reversed. It is only changed by |
| 795 | // Layout::layout. It should be a private member of Layout, but that |
| 796 | // would require layout.h to #include object.h to get the definition |
| 797 | // of Section_id. |
| 798 | static Unordered_set<Section_id, Section_id_hash> ctors_sections_in_init_array; |
| 799 | |
| 800 | // Return whether OBJECT/SHNDX is a .ctors/.dtors section mapped to a |
| 801 | // .init_array/.fini_array section. |
| 802 | |
| 803 | bool |
| 804 | Layout::is_ctors_in_init_array(Relobj* relobj, unsigned int shndx) const |
| 805 | { |
| 806 | return (ctors_sections_in_init_array.find(Section_id(relobj, shndx)) |
| 807 | != ctors_sections_in_init_array.end()); |
| 808 | } |
| 809 | |
| 810 | // Return the output section to use for section NAME with type TYPE |
| 811 | // and section flags FLAGS. NAME must be canonicalized in the string |
| 812 | // pool, and NAME_KEY is the key. ORDER is where this should appear |
| 813 | // in the output sections. IS_RELRO is true for a relro section. |
| 814 | |
| 815 | Output_section* |
| 816 | Layout::get_output_section(const char* name, Stringpool::Key name_key, |
| 817 | elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, |
| 818 | Output_section_order order, bool is_relro) |
| 819 | { |
| 820 | elfcpp::Elf_Word lookup_type = type; |
| 821 | |
| 822 | // For lookup purposes, treat INIT_ARRAY, FINI_ARRAY, and |
| 823 | // PREINIT_ARRAY like PROGBITS. This ensures that we combine |
| 824 | // .init_array, .fini_array, and .preinit_array sections by name |
| 825 | // whatever their type in the input file. We do this because the |
| 826 | // types are not always right in the input files. |
| 827 | if (lookup_type == elfcpp::SHT_INIT_ARRAY |
| 828 | || lookup_type == elfcpp::SHT_FINI_ARRAY |
| 829 | || lookup_type == elfcpp::SHT_PREINIT_ARRAY) |
| 830 | lookup_type = elfcpp::SHT_PROGBITS; |
| 831 | |
| 832 | elfcpp::Elf_Xword lookup_flags = flags; |
| 833 | |
| 834 | // Ignoring SHF_WRITE and SHF_EXECINSTR here means that we combine |
| 835 | // read-write with read-only sections. Some other ELF linkers do |
| 836 | // not do this. FIXME: Perhaps there should be an option |
| 837 | // controlling this. |
| 838 | lookup_flags &= ~(elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); |
| 839 | |
| 840 | const Key key(name_key, std::make_pair(lookup_type, lookup_flags)); |
| 841 | const std::pair<Key, Output_section*> v(key, NULL); |
| 842 | std::pair<Section_name_map::iterator, bool> ins( |
| 843 | this->section_name_map_.insert(v)); |
| 844 | |
| 845 | if (!ins.second) |
| 846 | return ins.first->second; |
| 847 | else |
| 848 | { |
| 849 | // This is the first time we've seen this name/type/flags |
| 850 | // combination. For compatibility with the GNU linker, we |
| 851 | // combine sections with contents and zero flags with sections |
| 852 | // with non-zero flags. This is a workaround for cases where |
| 853 | // assembler code forgets to set section flags. FIXME: Perhaps |
| 854 | // there should be an option to control this. |
| 855 | Output_section* os = NULL; |
| 856 | |
| 857 | if (lookup_type == elfcpp::SHT_PROGBITS) |
| 858 | { |
| 859 | if (flags == 0) |
| 860 | { |
| 861 | Output_section* same_name = this->find_output_section(name); |
| 862 | if (same_name != NULL |
| 863 | && (same_name->type() == elfcpp::SHT_PROGBITS |
| 864 | || same_name->type() == elfcpp::SHT_INIT_ARRAY |
| 865 | || same_name->type() == elfcpp::SHT_FINI_ARRAY |
| 866 | || same_name->type() == elfcpp::SHT_PREINIT_ARRAY) |
| 867 | && (same_name->flags() & elfcpp::SHF_TLS) == 0) |
| 868 | os = same_name; |
| 869 | } |
| 870 | else if ((flags & elfcpp::SHF_TLS) == 0) |
| 871 | { |
| 872 | elfcpp::Elf_Xword zero_flags = 0; |
| 873 | const Key zero_key(name_key, std::make_pair(lookup_type, |
| 874 | zero_flags)); |
| 875 | Section_name_map::iterator p = |
| 876 | this->section_name_map_.find(zero_key); |
| 877 | if (p != this->section_name_map_.end()) |
| 878 | os = p->second; |
| 879 | } |
| 880 | } |
| 881 | |
| 882 | if (os == NULL) |
| 883 | os = this->make_output_section(name, type, flags, order, is_relro); |
| 884 | |
| 885 | ins.first->second = os; |
| 886 | return os; |
| 887 | } |
| 888 | } |
| 889 | |
| 890 | // Returns TRUE iff NAME (an input section from RELOBJ) will |
| 891 | // be mapped to an output section that should be KEPT. |
| 892 | |
| 893 | bool |
| 894 | Layout::keep_input_section(const Relobj* relobj, const char* name) |
| 895 | { |
| 896 | if (! this->script_options_->saw_sections_clause()) |
| 897 | return false; |
| 898 | |
| 899 | Script_sections* ss = this->script_options_->script_sections(); |
| 900 | const char* file_name = relobj == NULL ? NULL : relobj->name().c_str(); |
| 901 | Output_section** output_section_slot; |
| 902 | Script_sections::Section_type script_section_type; |
| 903 | bool keep; |
| 904 | |
| 905 | name = ss->output_section_name(file_name, name, &output_section_slot, |
| 906 | &script_section_type, &keep, true); |
| 907 | return name != NULL && keep; |
| 908 | } |
| 909 | |
| 910 | // Clear the input section flags that should not be copied to the |
| 911 | // output section. |
| 912 | |
| 913 | elfcpp::Elf_Xword |
| 914 | Layout::get_output_section_flags(elfcpp::Elf_Xword input_section_flags) |
| 915 | { |
| 916 | // Some flags in the input section should not be automatically |
| 917 | // copied to the output section. |
| 918 | input_section_flags &= ~ (elfcpp::SHF_INFO_LINK |
| 919 | | elfcpp::SHF_GROUP |
| 920 | | elfcpp::SHF_COMPRESSED |
| 921 | | elfcpp::SHF_MERGE |
| 922 | | elfcpp::SHF_STRINGS); |
| 923 | |
| 924 | // We only clear the SHF_LINK_ORDER flag in for |
| 925 | // a non-relocatable link. |
| 926 | if (!parameters->options().relocatable()) |
| 927 | input_section_flags &= ~elfcpp::SHF_LINK_ORDER; |
| 928 | |
| 929 | return input_section_flags; |
| 930 | } |
| 931 | |
| 932 | // Pick the output section to use for section NAME, in input file |
| 933 | // RELOBJ, with type TYPE and flags FLAGS. RELOBJ may be NULL for a |
| 934 | // linker created section. IS_INPUT_SECTION is true if we are |
| 935 | // choosing an output section for an input section found in a input |
| 936 | // file. ORDER is where this section should appear in the output |
| 937 | // sections. IS_RELRO is true for a relro section. This will return |
| 938 | // NULL if the input section should be discarded. MATCH_INPUT_SPEC |
| 939 | // is true if the section name should be matched against input specs |
| 940 | // in a linker script. |
| 941 | |
| 942 | Output_section* |
| 943 | Layout::choose_output_section(const Relobj* relobj, const char* name, |
| 944 | elfcpp::Elf_Word type, elfcpp::Elf_Xword flags, |
| 945 | bool is_input_section, Output_section_order order, |
| 946 | bool is_relro, bool is_reloc, |
| 947 | bool match_input_spec) |
| 948 | { |
| 949 | // We should not see any input sections after we have attached |
| 950 | // sections to segments. |
| 951 | gold_assert(!is_input_section || !this->sections_are_attached_); |
| 952 | |
| 953 | flags = this->get_output_section_flags(flags); |
| 954 | |
| 955 | if (this->script_options_->saw_sections_clause() && !is_reloc) |
| 956 | { |
| 957 | // We are using a SECTIONS clause, so the output section is |
| 958 | // chosen based only on the name. |
| 959 | |
| 960 | Script_sections* ss = this->script_options_->script_sections(); |
| 961 | const char* file_name = relobj == NULL ? NULL : relobj->name().c_str(); |
| 962 | Output_section** output_section_slot; |
| 963 | Script_sections::Section_type script_section_type; |
| 964 | const char* orig_name = name; |
| 965 | bool keep; |
| 966 | name = ss->output_section_name(file_name, name, &output_section_slot, |
| 967 | &script_section_type, &keep, |
| 968 | match_input_spec); |
| 969 | |
| 970 | if (name == NULL) |
| 971 | { |
| 972 | gold_debug(DEBUG_SCRIPT, _("Unable to create output section '%s' " |
| 973 | "because it is not allowed by the " |
| 974 | "SECTIONS clause of the linker script"), |
| 975 | orig_name); |
| 976 | // The SECTIONS clause says to discard this input section. |
| 977 | return NULL; |
| 978 | } |
| 979 | |
| 980 | // We can only handle script section types ST_NONE and ST_NOLOAD. |
| 981 | switch (script_section_type) |
| 982 | { |
| 983 | case Script_sections::ST_NONE: |
| 984 | break; |
| 985 | case Script_sections::ST_NOLOAD: |
| 986 | flags &= elfcpp::SHF_ALLOC; |
| 987 | break; |
| 988 | default: |
| 989 | gold_unreachable(); |
| 990 | } |
| 991 | |
| 992 | // If this is an orphan section--one not mentioned in the linker |
| 993 | // script--then OUTPUT_SECTION_SLOT will be NULL, and we do the |
| 994 | // default processing below. |
| 995 | |
| 996 | if (output_section_slot != NULL) |
| 997 | { |
| 998 | if (*output_section_slot != NULL) |
| 999 | { |
| 1000 | (*output_section_slot)->update_flags_for_input_section(flags); |
| 1001 | return *output_section_slot; |
| 1002 | } |
| 1003 | |
| 1004 | // We don't put sections found in the linker script into |
| 1005 | // SECTION_NAME_MAP_. That keeps us from getting confused |
| 1006 | // if an orphan section is mapped to a section with the same |
| 1007 | // name as one in the linker script. |
| 1008 | |
| 1009 | name = this->namepool_.add(name, false, NULL); |
| 1010 | |
| 1011 | Output_section* os = this->make_output_section(name, type, flags, |
| 1012 | order, is_relro); |
| 1013 | |
| 1014 | os->set_found_in_sections_clause(); |
| 1015 | |
| 1016 | // Special handling for NOLOAD sections. |
| 1017 | if (script_section_type == Script_sections::ST_NOLOAD) |
| 1018 | { |
| 1019 | os->set_is_noload(); |
| 1020 | |
| 1021 | // The constructor of Output_section sets addresses of non-ALLOC |
| 1022 | // sections to 0 by default. We don't want that for NOLOAD |
| 1023 | // sections even if they have no SHF_ALLOC flag. |
| 1024 | if ((os->flags() & elfcpp::SHF_ALLOC) == 0 |
| 1025 | && os->is_address_valid()) |
| 1026 | { |
| 1027 | gold_assert(os->address() == 0 |
| 1028 | && !os->is_offset_valid() |
| 1029 | && !os->is_data_size_valid()); |
| 1030 | os->reset_address_and_file_offset(); |
| 1031 | } |
| 1032 | } |
| 1033 | |
| 1034 | *output_section_slot = os; |
| 1035 | return os; |
| 1036 | } |
| 1037 | } |
| 1038 | |
| 1039 | // FIXME: Handle SHF_OS_NONCONFORMING somewhere. |
| 1040 | |
| 1041 | size_t len = strlen(name); |
| 1042 | std::string uncompressed_name; |
| 1043 | |
| 1044 | // Compressed debug sections should be mapped to the corresponding |
| 1045 | // uncompressed section. |
| 1046 | if (is_compressed_debug_section(name)) |
| 1047 | { |
| 1048 | uncompressed_name = |
| 1049 | corresponding_uncompressed_section_name(std::string(name, len)); |
| 1050 | name = uncompressed_name.c_str(); |
| 1051 | len = uncompressed_name.length(); |
| 1052 | } |
| 1053 | |
| 1054 | // Turn NAME from the name of the input section into the name of the |
| 1055 | // output section. |
| 1056 | if (is_input_section |
| 1057 | && !this->script_options_->saw_sections_clause() |
| 1058 | && !parameters->options().relocatable()) |
| 1059 | { |
| 1060 | const char *orig_name = name; |
| 1061 | name = parameters->target().output_section_name(relobj, name, &len); |
| 1062 | if (name == NULL) |
| 1063 | name = Layout::output_section_name(relobj, orig_name, &len); |
| 1064 | } |
| 1065 | |
| 1066 | Stringpool::Key name_key; |
| 1067 | name = this->namepool_.add_with_length(name, len, true, &name_key); |
| 1068 | |
| 1069 | // Find or make the output section. The output section is selected |
| 1070 | // based on the section name, type, and flags. |
| 1071 | return this->get_output_section(name, name_key, type, flags, order, is_relro); |
| 1072 | } |
| 1073 | |
| 1074 | // For incremental links, record the initial fixed layout of a section |
| 1075 | // from the base file, and return a pointer to the Output_section. |
| 1076 | |
| 1077 | template<int size, bool big_endian> |
| 1078 | Output_section* |
| 1079 | Layout::init_fixed_output_section(const char* name, |
| 1080 | elfcpp::Shdr<size, big_endian>& shdr) |
| 1081 | { |
| 1082 | unsigned int sh_type = shdr.get_sh_type(); |
| 1083 | |
| 1084 | // We preserve the layout of PROGBITS, NOBITS, INIT_ARRAY, FINI_ARRAY, |
| 1085 | // PRE_INIT_ARRAY, and NOTE sections. |
| 1086 | // All others will be created from scratch and reallocated. |
| 1087 | if (!can_incremental_update(sh_type)) |
| 1088 | return NULL; |
| 1089 | |
| 1090 | // If we're generating a .gdb_index section, we need to regenerate |
| 1091 | // it from scratch. |
| 1092 | if (parameters->options().gdb_index() |
| 1093 | && sh_type == elfcpp::SHT_PROGBITS |
| 1094 | && strcmp(name, ".gdb_index") == 0) |
| 1095 | return NULL; |
| 1096 | |
| 1097 | typename elfcpp::Elf_types<size>::Elf_Addr sh_addr = shdr.get_sh_addr(); |
| 1098 | typename elfcpp::Elf_types<size>::Elf_Off sh_offset = shdr.get_sh_offset(); |
| 1099 | typename elfcpp::Elf_types<size>::Elf_WXword sh_size = shdr.get_sh_size(); |
| 1100 | typename elfcpp::Elf_types<size>::Elf_WXword sh_flags = shdr.get_sh_flags(); |
| 1101 | typename elfcpp::Elf_types<size>::Elf_WXword sh_addralign = |
| 1102 | shdr.get_sh_addralign(); |
| 1103 | |
| 1104 | // Make the output section. |
| 1105 | Stringpool::Key name_key; |
| 1106 | name = this->namepool_.add(name, true, &name_key); |
| 1107 | Output_section* os = this->get_output_section(name, name_key, sh_type, |
| 1108 | sh_flags, ORDER_INVALID, false); |
| 1109 | os->set_fixed_layout(sh_addr, sh_offset, sh_size, sh_addralign); |
| 1110 | if (sh_type != elfcpp::SHT_NOBITS) |
| 1111 | this->free_list_.remove(sh_offset, sh_offset + sh_size); |
| 1112 | return os; |
| 1113 | } |
| 1114 | |
| 1115 | // Return the index by which an input section should be ordered. This |
| 1116 | // is used to sort some .text sections, for compatibility with GNU ld. |
| 1117 | |
| 1118 | int |
| 1119 | Layout::special_ordering_of_input_section(const char* name) |
| 1120 | { |
| 1121 | // The GNU linker has some special handling for some sections that |
| 1122 | // wind up in the .text section. Sections that start with these |
| 1123 | // prefixes must appear first, and must appear in the order listed |
| 1124 | // here. |
| 1125 | static const char* const text_section_sort[] = |
| 1126 | { |
| 1127 | ".text.unlikely", |
| 1128 | ".text.exit", |
| 1129 | ".text.startup", |
| 1130 | ".text.hot" |
| 1131 | }; |
| 1132 | |
| 1133 | for (size_t i = 0; |
| 1134 | i < sizeof(text_section_sort) / sizeof(text_section_sort[0]); |
| 1135 | i++) |
| 1136 | if (is_prefix_of(text_section_sort[i], name)) |
| 1137 | return i; |
| 1138 | |
| 1139 | return -1; |
| 1140 | } |
| 1141 | |
| 1142 | // Return the output section to use for input section SHNDX, with name |
| 1143 | // NAME, with header HEADER, from object OBJECT. RELOC_SHNDX is the |
| 1144 | // index of a relocation section which applies to this section, or 0 |
| 1145 | // if none, or -1U if more than one. RELOC_TYPE is the type of the |
| 1146 | // relocation section if there is one. Set *OFF to the offset of this |
| 1147 | // input section without the output section. Return NULL if the |
| 1148 | // section should be discarded. Set *OFF to -1 if the section |
| 1149 | // contents should not be written directly to the output file, but |
| 1150 | // will instead receive special handling. |
| 1151 | |
| 1152 | template<int size, bool big_endian> |
| 1153 | Output_section* |
| 1154 | Layout::layout(Sized_relobj_file<size, big_endian>* object, unsigned int shndx, |
| 1155 | const char* name, const elfcpp::Shdr<size, big_endian>& shdr, |
| 1156 | unsigned int sh_type, unsigned int reloc_shndx, |
| 1157 | unsigned int, off_t* off) |
| 1158 | { |
| 1159 | *off = 0; |
| 1160 | |
| 1161 | if (!this->include_section(object, name, shdr)) |
| 1162 | return NULL; |
| 1163 | |
| 1164 | // In a relocatable link a grouped section must not be combined with |
| 1165 | // any other sections. |
| 1166 | Output_section* os; |
| 1167 | if (parameters->options().relocatable() |
| 1168 | && (shdr.get_sh_flags() & elfcpp::SHF_GROUP) != 0) |
| 1169 | { |
| 1170 | // Some flags in the input section should not be automatically |
| 1171 | // copied to the output section. |
| 1172 | elfcpp::Elf_Xword flags = (shdr.get_sh_flags() |
| 1173 | & ~ elfcpp::SHF_COMPRESSED); |
| 1174 | name = this->namepool_.add(name, true, NULL); |
| 1175 | os = this->make_output_section(name, sh_type, flags, |
| 1176 | ORDER_INVALID, false); |
| 1177 | } |
| 1178 | else |
| 1179 | { |
| 1180 | // All ".text.unlikely.*" sections can be moved to a unique |
| 1181 | // segment with --text-unlikely-segment option. |
| 1182 | bool text_unlikely_segment |
| 1183 | = (parameters->options().text_unlikely_segment() |
| 1184 | && is_prefix_of(".text.unlikely", |
| 1185 | object->section_name(shndx).c_str())); |
| 1186 | if (text_unlikely_segment) |
| 1187 | { |
| 1188 | elfcpp::Elf_Xword flags |
| 1189 | = this->get_output_section_flags(shdr.get_sh_flags()); |
| 1190 | |
| 1191 | Stringpool::Key name_key; |
| 1192 | const char* os_name = this->namepool_.add(".text.unlikely", true, |
| 1193 | &name_key); |
| 1194 | os = this->get_output_section(os_name, name_key, sh_type, flags, |
| 1195 | ORDER_INVALID, false); |
| 1196 | // Map this output section to a unique segment. This is done to |
| 1197 | // separate "text" that is not likely to be executed from "text" |
| 1198 | // that is likely executed. |
| 1199 | os->set_is_unique_segment(); |
| 1200 | } |
| 1201 | else |
| 1202 | { |
| 1203 | // Plugins can choose to place one or more subsets of sections in |
| 1204 | // unique segments and this is done by mapping these section subsets |
| 1205 | // to unique output sections. Check if this section needs to be |
| 1206 | // remapped to a unique output section. |
| 1207 | Section_segment_map::iterator it |
| 1208 | = this->section_segment_map_.find(Const_section_id(object, shndx)); |
| 1209 | if (it == this->section_segment_map_.end()) |
| 1210 | { |
| 1211 | os = this->choose_output_section(object, name, sh_type, |
| 1212 | shdr.get_sh_flags(), true, |
| 1213 | ORDER_INVALID, false, false, |
| 1214 | true); |
| 1215 | } |
| 1216 | else |
| 1217 | { |
| 1218 | // We know the name of the output section, directly call |
| 1219 | // get_output_section here by-passing choose_output_section. |
| 1220 | elfcpp::Elf_Xword flags |
| 1221 | = this->get_output_section_flags(shdr.get_sh_flags()); |
| 1222 | |
| 1223 | const char* os_name = it->second->name; |
| 1224 | Stringpool::Key name_key; |
| 1225 | os_name = this->namepool_.add(os_name, true, &name_key); |
| 1226 | os = this->get_output_section(os_name, name_key, sh_type, flags, |
| 1227 | ORDER_INVALID, false); |
| 1228 | if (!os->is_unique_segment()) |
| 1229 | { |
| 1230 | os->set_is_unique_segment(); |
| 1231 | os->set_extra_segment_flags(it->second->flags); |
| 1232 | os->set_segment_alignment(it->second->align); |
| 1233 | } |
| 1234 | } |
| 1235 | } |
| 1236 | if (os == NULL) |
| 1237 | return NULL; |
| 1238 | } |
| 1239 | |
| 1240 | // By default the GNU linker sorts input sections whose names match |
| 1241 | // .ctors.*, .dtors.*, .init_array.*, or .fini_array.*. The |
| 1242 | // sections are sorted by name. This is used to implement |
| 1243 | // constructor priority ordering. We are compatible. When we put |
| 1244 | // .ctor sections in .init_array and .dtor sections in .fini_array, |
| 1245 | // we must also sort plain .ctor and .dtor sections. |
| 1246 | if (!this->script_options_->saw_sections_clause() |
| 1247 | && !parameters->options().relocatable() |
| 1248 | && (is_prefix_of(".ctors.", name) |
| 1249 | || is_prefix_of(".dtors.", name) |
| 1250 | || is_prefix_of(".init_array.", name) |
| 1251 | || is_prefix_of(".fini_array.", name) |
| 1252 | || (parameters->options().ctors_in_init_array() |
| 1253 | && (strcmp(name, ".ctors") == 0 |
| 1254 | || strcmp(name, ".dtors") == 0)))) |
| 1255 | os->set_must_sort_attached_input_sections(); |
| 1256 | |
| 1257 | // By default the GNU linker sorts some special text sections ahead |
| 1258 | // of others. We are compatible. |
| 1259 | if (parameters->options().text_reorder() |
| 1260 | && !this->script_options_->saw_sections_clause() |
| 1261 | && !this->is_section_ordering_specified() |
| 1262 | && !parameters->options().relocatable() |
| 1263 | && Layout::special_ordering_of_input_section(name) >= 0) |
| 1264 | os->set_must_sort_attached_input_sections(); |
| 1265 | |
| 1266 | // If this is a .ctors or .ctors.* section being mapped to a |
| 1267 | // .init_array section, or a .dtors or .dtors.* section being mapped |
| 1268 | // to a .fini_array section, we will need to reverse the words if |
| 1269 | // there is more than one. Record this section for later. See |
| 1270 | // ctors_sections_in_init_array above. |
| 1271 | if (!this->script_options_->saw_sections_clause() |
| 1272 | && !parameters->options().relocatable() |
| 1273 | && shdr.get_sh_size() > size / 8 |
| 1274 | && (((strcmp(name, ".ctors") == 0 |
| 1275 | || is_prefix_of(".ctors.", name)) |
| 1276 | && strcmp(os->name(), ".init_array") == 0) |
| 1277 | || ((strcmp(name, ".dtors") == 0 |
| 1278 | || is_prefix_of(".dtors.", name)) |
| 1279 | && strcmp(os->name(), ".fini_array") == 0))) |
| 1280 | ctors_sections_in_init_array.insert(Section_id(object, shndx)); |
| 1281 | |
| 1282 | // FIXME: Handle SHF_LINK_ORDER somewhere. |
| 1283 | |
| 1284 | elfcpp::Elf_Xword orig_flags = os->flags(); |
| 1285 | |
| 1286 | *off = os->add_input_section(this, object, shndx, name, shdr, reloc_shndx, |
| 1287 | this->script_options_->saw_sections_clause()); |
| 1288 | |
| 1289 | // If the flags changed, we may have to change the order. |
| 1290 | if ((orig_flags & elfcpp::SHF_ALLOC) != 0) |
| 1291 | { |
| 1292 | orig_flags &= (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); |
| 1293 | elfcpp::Elf_Xword new_flags = |
| 1294 | os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR); |
| 1295 | if (orig_flags != new_flags) |
| 1296 | os->set_order(this->default_section_order(os, false)); |
| 1297 | } |
| 1298 | |
| 1299 | this->have_added_input_section_ = true; |
| 1300 | |
| 1301 | return os; |
| 1302 | } |
| 1303 | |
| 1304 | // Maps section SECN to SEGMENT s. |
| 1305 | void |
| 1306 | Layout::insert_section_segment_map(Const_section_id secn, |
| 1307 | Unique_segment_info *s) |
| 1308 | { |
| 1309 | gold_assert(this->unique_segment_for_sections_specified_); |
| 1310 | this->section_segment_map_[secn] = s; |
| 1311 | } |
| 1312 | |
| 1313 | // Handle a relocation section when doing a relocatable link. |
| 1314 | |
| 1315 | template<int size, bool big_endian> |
| 1316 | Output_section* |
| 1317 | Layout::layout_reloc(Sized_relobj_file<size, big_endian>*, |
| 1318 | unsigned int, |
| 1319 | const elfcpp::Shdr<size, big_endian>& shdr, |
| 1320 | Output_section* data_section, |
| 1321 | Relocatable_relocs* rr) |
| 1322 | { |
| 1323 | gold_assert(parameters->options().relocatable() |
| 1324 | || parameters->options().emit_relocs()); |
| 1325 | |
| 1326 | int sh_type = shdr.get_sh_type(); |
| 1327 | |
| 1328 | std::string name; |
| 1329 | if (sh_type == elfcpp::SHT_REL) |
| 1330 | name = ".rel"; |
| 1331 | else if (sh_type == elfcpp::SHT_RELA) |
| 1332 | name = ".rela"; |
| 1333 | else |
| 1334 | gold_unreachable(); |
| 1335 | name += data_section->name(); |
| 1336 | |
| 1337 | // If the output data section already has a reloc section, use that; |
| 1338 | // otherwise, make a new one. |
| 1339 | Output_section* os = data_section->reloc_section(); |
| 1340 | if (os == NULL) |
| 1341 | { |
| 1342 | const char* n = this->namepool_.add(name.c_str(), true, NULL); |
| 1343 | os = this->make_output_section(n, sh_type, shdr.get_sh_flags(), |
| 1344 | ORDER_INVALID, false); |
| 1345 | os->set_should_link_to_symtab(); |
| 1346 | os->set_info_section(data_section); |
| 1347 | data_section->set_reloc_section(os); |
| 1348 | } |
| 1349 | |
| 1350 | Output_section_data* posd; |
| 1351 | if (sh_type == elfcpp::SHT_REL) |
| 1352 | { |
| 1353 | os->set_entsize(elfcpp::Elf_sizes<size>::rel_size); |
| 1354 | posd = new Output_relocatable_relocs<elfcpp::SHT_REL, |
| 1355 | size, |
| 1356 | big_endian>(rr); |
| 1357 | } |
| 1358 | else if (sh_type == elfcpp::SHT_RELA) |
| 1359 | { |
| 1360 | os->set_entsize(elfcpp::Elf_sizes<size>::rela_size); |
| 1361 | posd = new Output_relocatable_relocs<elfcpp::SHT_RELA, |
| 1362 | size, |
| 1363 | big_endian>(rr); |
| 1364 | } |
| 1365 | else |
| 1366 | gold_unreachable(); |
| 1367 | |
| 1368 | os->add_output_section_data(posd); |
| 1369 | rr->set_output_data(posd); |
| 1370 | |
| 1371 | return os; |
| 1372 | } |
| 1373 | |
| 1374 | // Handle a group section when doing a relocatable link. |
| 1375 | |
| 1376 | template<int size, bool big_endian> |
| 1377 | void |
| 1378 | Layout::layout_group(Symbol_table* symtab, |
| 1379 | Sized_relobj_file<size, big_endian>* object, |
| 1380 | unsigned int, |
| 1381 | const char* group_section_name, |
| 1382 | const char* signature, |
| 1383 | const elfcpp::Shdr<size, big_endian>& shdr, |
| 1384 | elfcpp::Elf_Word flags, |
| 1385 | std::vector<unsigned int>* shndxes) |
| 1386 | { |
| 1387 | gold_assert(parameters->options().relocatable()); |
| 1388 | gold_assert(shdr.get_sh_type() == elfcpp::SHT_GROUP); |
| 1389 | group_section_name = this->namepool_.add(group_section_name, true, NULL); |
| 1390 | Output_section* os = this->make_output_section(group_section_name, |
| 1391 | elfcpp::SHT_GROUP, |
| 1392 | shdr.get_sh_flags(), |
| 1393 | ORDER_INVALID, false); |
| 1394 | |
| 1395 | // We need to find a symbol with the signature in the symbol table. |
| 1396 | // If we don't find one now, we need to look again later. |
| 1397 | Symbol* sym = symtab->lookup(signature, NULL); |
| 1398 | if (sym != NULL) |
| 1399 | os->set_info_symndx(sym); |
| 1400 | else |
| 1401 | { |
| 1402 | // Reserve some space to minimize reallocations. |
| 1403 | if (this->group_signatures_.empty()) |
| 1404 | this->group_signatures_.reserve(this->number_of_input_files_ * 16); |
| 1405 | |
| 1406 | // We will wind up using a symbol whose name is the signature. |
| 1407 | // So just put the signature in the symbol name pool to save it. |
| 1408 | signature = symtab->canonicalize_name(signature); |
| 1409 | this->group_signatures_.push_back(Group_signature(os, signature)); |
| 1410 | } |
| 1411 | |
| 1412 | os->set_should_link_to_symtab(); |
| 1413 | os->set_entsize(4); |
| 1414 | |
| 1415 | section_size_type entry_count = |
| 1416 | convert_to_section_size_type(shdr.get_sh_size() / 4); |
| 1417 | Output_section_data* posd = |
| 1418 | new Output_data_group<size, big_endian>(object, entry_count, flags, |
| 1419 | shndxes); |
| 1420 | os->add_output_section_data(posd); |
| 1421 | } |
| 1422 | |
| 1423 | // Special GNU handling of sections name .eh_frame. They will |
| 1424 | // normally hold exception frame data as defined by the C++ ABI |
| 1425 | // (http://codesourcery.com/cxx-abi/). |
| 1426 | |
| 1427 | template<int size, bool big_endian> |
| 1428 | Output_section* |
| 1429 | Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object, |
| 1430 | const unsigned char* symbols, |
| 1431 | off_t symbols_size, |
| 1432 | const unsigned char* symbol_names, |
| 1433 | off_t symbol_names_size, |
| 1434 | unsigned int shndx, |
| 1435 | const elfcpp::Shdr<size, big_endian>& shdr, |
| 1436 | unsigned int reloc_shndx, unsigned int reloc_type, |
| 1437 | off_t* off) |
| 1438 | { |
| 1439 | const unsigned int unwind_section_type = |
| 1440 | parameters->target().unwind_section_type(); |
| 1441 | |
| 1442 | gold_assert(shdr.get_sh_type() == elfcpp::SHT_PROGBITS |
| 1443 | || shdr.get_sh_type() == unwind_section_type); |
| 1444 | gold_assert((shdr.get_sh_flags() & elfcpp::SHF_ALLOC) != 0); |
| 1445 | |
| 1446 | Output_section* os = this->make_eh_frame_section(object); |
| 1447 | if (os == NULL) |
| 1448 | return NULL; |
| 1449 | |
| 1450 | gold_assert(this->eh_frame_section_ == os); |
| 1451 | |
| 1452 | elfcpp::Elf_Xword orig_flags = os->flags(); |
| 1453 | |
| 1454 | Eh_frame::Eh_frame_section_disposition disp = |
| 1455 | Eh_frame::EH_UNRECOGNIZED_SECTION; |
| 1456 | if (!parameters->incremental()) |
| 1457 | { |
| 1458 | disp = this->eh_frame_data_->add_ehframe_input_section(object, |
| 1459 | symbols, |
| 1460 | symbols_size, |
| 1461 | symbol_names, |
| 1462 | symbol_names_size, |
| 1463 | shndx, |
| 1464 | reloc_shndx, |
| 1465 | reloc_type); |
| 1466 | } |
| 1467 | |
| 1468 | if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION) |
| 1469 | { |
| 1470 | os->update_flags_for_input_section(shdr.get_sh_flags()); |
| 1471 | |
| 1472 | // A writable .eh_frame section is a RELRO section. |
| 1473 | if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)) |
| 1474 | != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))) |
| 1475 | { |
| 1476 | os->set_is_relro(); |
| 1477 | os->set_order(ORDER_RELRO); |
| 1478 | } |
| 1479 | |
| 1480 | *off = -1; |
| 1481 | return os; |
| 1482 | } |
| 1483 | |
| 1484 | if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_) |
| 1485 | { |
| 1486 | // We found the end marker section, so now we can add the set of |
| 1487 | // optimized sections to the output section. We need to postpone |
| 1488 | // adding this until we've found a section we can optimize so that |
| 1489 | // the .eh_frame section in crtbeginT.o winds up at the start of |
| 1490 | // the output section. |
| 1491 | os->add_output_section_data(this->eh_frame_data_); |
| 1492 | this->added_eh_frame_data_ = true; |
| 1493 | } |
| 1494 | |
| 1495 | // We couldn't handle this .eh_frame section for some reason. |
| 1496 | // Add it as a normal section. |
| 1497 | bool saw_sections_clause = this->script_options_->saw_sections_clause(); |
| 1498 | *off = os->add_input_section(this, object, shndx, ".eh_frame", shdr, |
| 1499 | reloc_shndx, saw_sections_clause); |
| 1500 | this->have_added_input_section_ = true; |
| 1501 | |
| 1502 | if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)) |
| 1503 | != (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))) |
| 1504 | os->set_order(this->default_section_order(os, false)); |
| 1505 | |
| 1506 | return os; |
| 1507 | } |
| 1508 | |
| 1509 | void |
| 1510 | Layout::finalize_eh_frame_section() |
| 1511 | { |
| 1512 | // If we never found an end marker section, we need to add the |
| 1513 | // optimized eh sections to the output section now. |
| 1514 | if (!parameters->incremental() |
| 1515 | && this->eh_frame_section_ != NULL |
| 1516 | && !this->added_eh_frame_data_) |
| 1517 | { |
| 1518 | this->eh_frame_section_->add_output_section_data(this->eh_frame_data_); |
| 1519 | this->added_eh_frame_data_ = true; |
| 1520 | } |
| 1521 | } |
| 1522 | |
| 1523 | // Create and return the magic .eh_frame section. Create |
| 1524 | // .eh_frame_hdr also if appropriate. OBJECT is the object with the |
| 1525 | // input .eh_frame section; it may be NULL. |
| 1526 | |
| 1527 | Output_section* |
| 1528 | Layout::make_eh_frame_section(const Relobj* object) |
| 1529 | { |
| 1530 | const unsigned int unwind_section_type = |
| 1531 | parameters->target().unwind_section_type(); |
| 1532 | |
| 1533 | Output_section* os = this->choose_output_section(object, ".eh_frame", |
| 1534 | unwind_section_type, |
| 1535 | elfcpp::SHF_ALLOC, false, |
| 1536 | ORDER_EHFRAME, false, false, |
| 1537 | false); |
| 1538 | if (os == NULL) |
| 1539 | return NULL; |
| 1540 | |
| 1541 | if (this->eh_frame_section_ == NULL) |
| 1542 | { |
| 1543 | this->eh_frame_section_ = os; |
| 1544 | this->eh_frame_data_ = new Eh_frame(); |
| 1545 | |
| 1546 | // For incremental linking, we do not optimize .eh_frame sections |
| 1547 | // or create a .eh_frame_hdr section. |
| 1548 | if (parameters->options().eh_frame_hdr() && !parameters->incremental()) |
| 1549 | { |
| 1550 | Output_section* hdr_os = |
| 1551 | this->choose_output_section(NULL, ".eh_frame_hdr", |
| 1552 | unwind_section_type, |
| 1553 | elfcpp::SHF_ALLOC, false, |
| 1554 | ORDER_EHFRAME, false, false, |
| 1555 | false); |
| 1556 | |
| 1557 | if (hdr_os != NULL) |
| 1558 | { |
| 1559 | Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os, |
| 1560 | this->eh_frame_data_); |
| 1561 | hdr_os->add_output_section_data(hdr_posd); |
| 1562 | |
| 1563 | hdr_os->set_after_input_sections(); |
| 1564 | |
| 1565 | if (!this->script_options_->saw_phdrs_clause()) |
| 1566 | { |
| 1567 | Output_segment* hdr_oseg; |
| 1568 | hdr_oseg = this->make_output_segment(elfcpp::PT_GNU_EH_FRAME, |
| 1569 | elfcpp::PF_R); |
| 1570 | hdr_oseg->add_output_section_to_nonload(hdr_os, |
| 1571 | elfcpp::PF_R); |
| 1572 | } |
| 1573 | |
| 1574 | this->eh_frame_data_->set_eh_frame_hdr(hdr_posd); |
| 1575 | } |
| 1576 | } |
| 1577 | } |
| 1578 | |
| 1579 | return os; |
| 1580 | } |
| 1581 | |
| 1582 | // Add an exception frame for a PLT. This is called from target code. |
| 1583 | |
| 1584 | void |
| 1585 | Layout::add_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data, |
| 1586 | size_t cie_length, const unsigned char* fde_data, |
| 1587 | size_t fde_length) |
| 1588 | { |
| 1589 | if (parameters->incremental()) |
| 1590 | { |
| 1591 | // FIXME: Maybe this could work some day.... |
| 1592 | return; |
| 1593 | } |
| 1594 | Output_section* os = this->make_eh_frame_section(NULL); |
| 1595 | if (os == NULL) |
| 1596 | return; |
| 1597 | this->eh_frame_data_->add_ehframe_for_plt(plt, cie_data, cie_length, |
| 1598 | fde_data, fde_length); |
| 1599 | if (!this->added_eh_frame_data_) |
| 1600 | { |
| 1601 | os->add_output_section_data(this->eh_frame_data_); |
| 1602 | this->added_eh_frame_data_ = true; |
| 1603 | } |
| 1604 | } |
| 1605 | |
| 1606 | // Remove .eh_frame information for a PLT. FDEs using the CIE must |
| 1607 | // be removed in reverse order to the order they were added. |
| 1608 | |
| 1609 | void |
| 1610 | Layout::remove_eh_frame_for_plt(Output_data* plt, const unsigned char* cie_data, |
| 1611 | size_t cie_length, const unsigned char* fde_data, |
| 1612 | size_t fde_length) |
| 1613 | { |
| 1614 | if (parameters->incremental()) |
| 1615 | { |
| 1616 | // FIXME: Maybe this could work some day.... |
| 1617 | return; |
| 1618 | } |
| 1619 | this->eh_frame_data_->remove_ehframe_for_plt(plt, cie_data, cie_length, |
| 1620 | fde_data, fde_length); |
| 1621 | } |
| 1622 | |
| 1623 | // Scan a .debug_info or .debug_types section, and add summary |
| 1624 | // information to the .gdb_index section. |
| 1625 | |
| 1626 | template<int size, bool big_endian> |
| 1627 | void |
| 1628 | Layout::add_to_gdb_index(bool is_type_unit, |
| 1629 | Sized_relobj<size, big_endian>* object, |
| 1630 | const unsigned char* symbols, |
| 1631 | off_t symbols_size, |
| 1632 | unsigned int shndx, |
| 1633 | unsigned int reloc_shndx, |
| 1634 | unsigned int reloc_type) |
| 1635 | { |
| 1636 | if (this->gdb_index_data_ == NULL) |
| 1637 | { |
| 1638 | Output_section* os = this->choose_output_section(NULL, ".gdb_index", |
| 1639 | elfcpp::SHT_PROGBITS, 0, |
| 1640 | false, ORDER_INVALID, |
| 1641 | false, false, false); |
| 1642 | if (os == NULL) |
| 1643 | return; |
| 1644 | |
| 1645 | this->gdb_index_data_ = new Gdb_index(os); |
| 1646 | os->add_output_section_data(this->gdb_index_data_); |
| 1647 | os->set_after_input_sections(); |
| 1648 | } |
| 1649 | |
| 1650 | this->gdb_index_data_->scan_debug_info(is_type_unit, object, symbols, |
| 1651 | symbols_size, shndx, reloc_shndx, |
| 1652 | reloc_type); |
| 1653 | } |
| 1654 | |
| 1655 | // Add POSD to an output section using NAME, TYPE, and FLAGS. Return |
| 1656 | // the output section. |
| 1657 | |
| 1658 | Output_section* |
| 1659 | Layout::add_output_section_data(const char* name, elfcpp::Elf_Word type, |
| 1660 | elfcpp::Elf_Xword flags, |
| 1661 | Output_section_data* posd, |
| 1662 | Output_section_order order, bool is_relro) |
| 1663 | { |
| 1664 | Output_section* os = this->choose_output_section(NULL, name, type, flags, |
| 1665 | false, order, is_relro, |
| 1666 | false, false); |
| 1667 | if (os != NULL) |
| 1668 | os->add_output_section_data(posd); |
| 1669 | return os; |
| 1670 | } |
| 1671 | |
| 1672 | // Map section flags to segment flags. |
| 1673 | |
| 1674 | elfcpp::Elf_Word |
| 1675 | Layout::section_flags_to_segment(elfcpp::Elf_Xword flags) |
| 1676 | { |
| 1677 | elfcpp::Elf_Word ret = elfcpp::PF_R; |
| 1678 | if ((flags & elfcpp::SHF_WRITE) != 0) |
| 1679 | ret |= elfcpp::PF_W; |
| 1680 | if ((flags & elfcpp::SHF_EXECINSTR) != 0) |
| 1681 | ret |= elfcpp::PF_X; |
| 1682 | return ret; |
| 1683 | } |
| 1684 | |
| 1685 | // Make a new Output_section, and attach it to segments as |
| 1686 | // appropriate. ORDER is the order in which this section should |
| 1687 | // appear in the output segment. IS_RELRO is true if this is a relro |
| 1688 | // (read-only after relocations) section. |
| 1689 | |
| 1690 | Output_section* |
| 1691 | Layout::make_output_section(const char* name, elfcpp::Elf_Word type, |
| 1692 | elfcpp::Elf_Xword flags, |
| 1693 | Output_section_order order, bool is_relro) |
| 1694 | { |
| 1695 | Output_section* os; |
| 1696 | if ((flags & elfcpp::SHF_ALLOC) == 0 |
| 1697 | && strcmp(parameters->options().compress_debug_sections(), "none") != 0 |
| 1698 | && is_compressible_debug_section(name)) |
| 1699 | os = new Output_compressed_section(¶meters->options(), name, type, |
| 1700 | flags); |
| 1701 | else if ((flags & elfcpp::SHF_ALLOC) == 0 |
| 1702 | && parameters->options().strip_debug_non_line() |
| 1703 | && strcmp(".debug_abbrev", name) == 0) |
| 1704 | { |
| 1705 | os = this->debug_abbrev_ = new Output_reduced_debug_abbrev_section( |
| 1706 | name, type, flags); |
| 1707 | if (this->debug_info_) |
| 1708 | this->debug_info_->set_abbreviations(this->debug_abbrev_); |
| 1709 | } |
| 1710 | else if ((flags & elfcpp::SHF_ALLOC) == 0 |
| 1711 | && parameters->options().strip_debug_non_line() |
| 1712 | && strcmp(".debug_info", name) == 0) |
| 1713 | { |
| 1714 | os = this->debug_info_ = new Output_reduced_debug_info_section( |
| 1715 | name, type, flags); |
| 1716 | if (this->debug_abbrev_) |
| 1717 | this->debug_info_->set_abbreviations(this->debug_abbrev_); |
| 1718 | } |
| 1719 | else |
| 1720 | { |
| 1721 | // Sometimes .init_array*, .preinit_array* and .fini_array* do |
| 1722 | // not have correct section types. Force them here. |
| 1723 | if (type == elfcpp::SHT_PROGBITS) |
| 1724 | { |
| 1725 | if (is_prefix_of(".init_array", name)) |
| 1726 | type = elfcpp::SHT_INIT_ARRAY; |
| 1727 | else if (is_prefix_of(".preinit_array", name)) |
| 1728 | type = elfcpp::SHT_PREINIT_ARRAY; |
| 1729 | else if (is_prefix_of(".fini_array", name)) |
| 1730 | type = elfcpp::SHT_FINI_ARRAY; |
| 1731 | } |
| 1732 | |
| 1733 | // FIXME: const_cast is ugly. |
| 1734 | Target* target = const_cast<Target*>(¶meters->target()); |
| 1735 | os = target->make_output_section(name, type, flags); |
| 1736 | } |
| 1737 | |
| 1738 | // With -z relro, we have to recognize the special sections by name. |
| 1739 | // There is no other way. |
| 1740 | bool is_relro_local = false; |
| 1741 | if (!this->script_options_->saw_sections_clause() |
| 1742 | && parameters->options().relro() |
| 1743 | && (flags & elfcpp::SHF_ALLOC) != 0 |
| 1744 | && (flags & elfcpp::SHF_WRITE) != 0) |
| 1745 | { |
| 1746 | if (type == elfcpp::SHT_PROGBITS) |
| 1747 | { |
| 1748 | if ((flags & elfcpp::SHF_TLS) != 0) |
| 1749 | is_relro = true; |
| 1750 | else if (strcmp(name, ".data.rel.ro") == 0) |
| 1751 | is_relro = true; |
| 1752 | else if (strcmp(name, ".data.rel.ro.local") == 0) |
| 1753 | { |
| 1754 | is_relro = true; |
| 1755 | is_relro_local = true; |
| 1756 | } |
| 1757 | else if (strcmp(name, ".ctors") == 0 |
| 1758 | || strcmp(name, ".dtors") == 0 |
| 1759 | || strcmp(name, ".jcr") == 0) |
| 1760 | is_relro = true; |
| 1761 | } |
| 1762 | else if (type == elfcpp::SHT_INIT_ARRAY |
| 1763 | || type == elfcpp::SHT_FINI_ARRAY |
| 1764 | || type == elfcpp::SHT_PREINIT_ARRAY) |
| 1765 | is_relro = true; |
| 1766 | } |
| 1767 | |
| 1768 | if (is_relro) |
| 1769 | os->set_is_relro(); |
| 1770 | |
| 1771 | if (order == ORDER_INVALID && (flags & elfcpp::SHF_ALLOC) != 0) |
| 1772 | order = this->default_section_order(os, is_relro_local); |
| 1773 | |
| 1774 | os->set_order(order); |
| 1775 | |
| 1776 | parameters->target().new_output_section(os); |
| 1777 | |
| 1778 | this->section_list_.push_back(os); |
| 1779 | |
| 1780 | // The GNU linker by default sorts some sections by priority, so we |
| 1781 | // do the same. We need to know that this might happen before we |
| 1782 | // attach any input sections. |
| 1783 | if (!this->script_options_->saw_sections_clause() |
| 1784 | && !parameters->options().relocatable() |
| 1785 | && (strcmp(name, ".init_array") == 0 |
| 1786 | || strcmp(name, ".fini_array") == 0 |
| 1787 | || (!parameters->options().ctors_in_init_array() |
| 1788 | && (strcmp(name, ".ctors") == 0 |
| 1789 | || strcmp(name, ".dtors") == 0)))) |
| 1790 | os->set_may_sort_attached_input_sections(); |
| 1791 | |
| 1792 | // The GNU linker by default sorts .text.{unlikely,exit,startup,hot} |
| 1793 | // sections before other .text sections. We are compatible. We |
| 1794 | // need to know that this might happen before we attach any input |
| 1795 | // sections. |
| 1796 | if (parameters->options().text_reorder() |
| 1797 | && !this->script_options_->saw_sections_clause() |
| 1798 | && !this->is_section_ordering_specified() |
| 1799 | && !parameters->options().relocatable() |
| 1800 | && strcmp(name, ".text") == 0) |
| 1801 | os->set_may_sort_attached_input_sections(); |
| 1802 | |
| 1803 | // GNU linker sorts section by name with --sort-section=name. |
| 1804 | if (strcmp(parameters->options().sort_section(), "name") == 0) |
| 1805 | os->set_must_sort_attached_input_sections(); |
| 1806 | |
| 1807 | // Check for .stab*str sections, as .stab* sections need to link to |
| 1808 | // them. |
| 1809 | if (type == elfcpp::SHT_STRTAB |
| 1810 | && !this->have_stabstr_section_ |
| 1811 | && strncmp(name, ".stab", 5) == 0 |
| 1812 | && strcmp(name + strlen(name) - 3, "str") == 0) |
| 1813 | this->have_stabstr_section_ = true; |
| 1814 | |
| 1815 | // During a full incremental link, we add patch space to most |
| 1816 | // PROGBITS and NOBITS sections. Flag those that may be |
| 1817 | // arbitrarily padded. |
| 1818 | if ((type == elfcpp::SHT_PROGBITS || type == elfcpp::SHT_NOBITS) |
| 1819 | && order != ORDER_INTERP |
| 1820 | && order != ORDER_INIT |
| 1821 | && order != ORDER_PLT |
| 1822 | && order != ORDER_FINI |
| 1823 | && order != ORDER_RELRO_LAST |
| 1824 | && order != ORDER_NON_RELRO_FIRST |
| 1825 | && strcmp(name, ".eh_frame") != 0 |
| 1826 | && strcmp(name, ".ctors") != 0 |
| 1827 | && strcmp(name, ".dtors") != 0 |
| 1828 | && strcmp(name, ".jcr") != 0) |
| 1829 | { |
| 1830 | os->set_is_patch_space_allowed(); |
| 1831 | |
| 1832 | // Certain sections require "holes" to be filled with |
| 1833 | // specific fill patterns. These fill patterns may have |
| 1834 | // a minimum size, so we must prevent allocations from the |
| 1835 | // free list that leave a hole smaller than the minimum. |
| 1836 | if (strcmp(name, ".debug_info") == 0) |
| 1837 | os->set_free_space_fill(new Output_fill_debug_info(false)); |
| 1838 | else if (strcmp(name, ".debug_types") == 0) |
| 1839 | os->set_free_space_fill(new Output_fill_debug_info(true)); |
| 1840 | else if (strcmp(name, ".debug_line") == 0) |
| 1841 | os->set_free_space_fill(new Output_fill_debug_line()); |
| 1842 | } |
| 1843 | |
| 1844 | // If we have already attached the sections to segments, then we |
| 1845 | // need to attach this one now. This happens for sections created |
| 1846 | // directly by the linker. |
| 1847 | if (this->sections_are_attached_) |
| 1848 | this->attach_section_to_segment(¶meters->target(), os); |
| 1849 | |
| 1850 | return os; |
| 1851 | } |
| 1852 | |
| 1853 | // Return the default order in which a section should be placed in an |
| 1854 | // output segment. This function captures a lot of the ideas in |
| 1855 | // ld/scripttempl/elf.sc in the GNU linker. Note that the order of a |
| 1856 | // linker created section is normally set when the section is created; |
| 1857 | // this function is used for input sections. |
| 1858 | |
| 1859 | Output_section_order |
| 1860 | Layout::default_section_order(Output_section* os, bool is_relro_local) |
| 1861 | { |
| 1862 | gold_assert((os->flags() & elfcpp::SHF_ALLOC) != 0); |
| 1863 | bool is_write = (os->flags() & elfcpp::SHF_WRITE) != 0; |
| 1864 | bool is_execinstr = (os->flags() & elfcpp::SHF_EXECINSTR) != 0; |
| 1865 | bool is_bss = false; |
| 1866 | |
| 1867 | switch (os->type()) |
| 1868 | { |
| 1869 | default: |
| 1870 | case elfcpp::SHT_PROGBITS: |
| 1871 | break; |
| 1872 | case elfcpp::SHT_NOBITS: |
| 1873 | is_bss = true; |
| 1874 | break; |
| 1875 | case elfcpp::SHT_RELA: |
| 1876 | case elfcpp::SHT_REL: |
| 1877 | if (!is_write) |
| 1878 | return ORDER_DYNAMIC_RELOCS; |
| 1879 | break; |
| 1880 | case elfcpp::SHT_HASH: |
| 1881 | case elfcpp::SHT_DYNAMIC: |
| 1882 | case elfcpp::SHT_SHLIB: |
| 1883 | case elfcpp::SHT_DYNSYM: |
| 1884 | case elfcpp::SHT_GNU_HASH: |
| 1885 | case elfcpp::SHT_GNU_verdef: |
| 1886 | case elfcpp::SHT_GNU_verneed: |
| 1887 | case elfcpp::SHT_GNU_versym: |
| 1888 | if (!is_write) |
| 1889 | return ORDER_DYNAMIC_LINKER; |
| 1890 | break; |
| 1891 | case elfcpp::SHT_NOTE: |
| 1892 | return is_write ? ORDER_RW_NOTE : ORDER_RO_NOTE; |
| 1893 | } |
| 1894 | |
| 1895 | if ((os->flags() & elfcpp::SHF_TLS) != 0) |
| 1896 | return is_bss ? ORDER_TLS_BSS : ORDER_TLS_DATA; |
| 1897 | |
| 1898 | if (!is_bss && !is_write) |
| 1899 | { |
| 1900 | if (is_execinstr) |
| 1901 | { |
| 1902 | if (strcmp(os->name(), ".init") == 0) |
| 1903 | return ORDER_INIT; |
| 1904 | else if (strcmp(os->name(), ".fini") == 0) |
| 1905 | return ORDER_FINI; |
| 1906 | else if (parameters->options().keep_text_section_prefix()) |
| 1907 | { |
| 1908 | // -z,keep-text-section-prefix introduces additional |
| 1909 | // output sections. |
| 1910 | if (strcmp(os->name(), ".text.hot") == 0) |
| 1911 | return ORDER_TEXT_HOT; |
| 1912 | else if (strcmp(os->name(), ".text.startup") == 0) |
| 1913 | return ORDER_TEXT_STARTUP; |
| 1914 | else if (strcmp(os->name(), ".text.exit") == 0) |
| 1915 | return ORDER_TEXT_EXIT; |
| 1916 | else if (strcmp(os->name(), ".text.unlikely") == 0) |
| 1917 | return ORDER_TEXT_UNLIKELY; |
| 1918 | } |
| 1919 | } |
| 1920 | return is_execinstr ? ORDER_TEXT : ORDER_READONLY; |
| 1921 | } |
| 1922 | |
| 1923 | if (os->is_relro()) |
| 1924 | return is_relro_local ? ORDER_RELRO_LOCAL : ORDER_RELRO; |
| 1925 | |
| 1926 | if (os->is_small_section()) |
| 1927 | return is_bss ? ORDER_SMALL_BSS : ORDER_SMALL_DATA; |
| 1928 | if (os->is_large_section()) |
| 1929 | return is_bss ? ORDER_LARGE_BSS : ORDER_LARGE_DATA; |
| 1930 | |
| 1931 | return is_bss ? ORDER_BSS : ORDER_DATA; |
| 1932 | } |
| 1933 | |
| 1934 | // Attach output sections to segments. This is called after we have |
| 1935 | // seen all the input sections. |
| 1936 | |
| 1937 | void |
| 1938 | Layout::attach_sections_to_segments(const Target* target) |
| 1939 | { |
| 1940 | for (Section_list::iterator p = this->section_list_.begin(); |
| 1941 | p != this->section_list_.end(); |
| 1942 | ++p) |
| 1943 | this->attach_section_to_segment(target, *p); |
| 1944 | |
| 1945 | this->sections_are_attached_ = true; |
| 1946 | } |
| 1947 | |
| 1948 | // Attach an output section to a segment. |
| 1949 | |
| 1950 | void |
| 1951 | Layout::attach_section_to_segment(const Target* target, Output_section* os) |
| 1952 | { |
| 1953 | if ((os->flags() & elfcpp::SHF_ALLOC) == 0) |
| 1954 | this->unattached_section_list_.push_back(os); |
| 1955 | else |
| 1956 | this->attach_allocated_section_to_segment(target, os); |
| 1957 | } |
| 1958 | |
| 1959 | // Attach an allocated output section to a segment. |
| 1960 | |
| 1961 | void |
| 1962 | Layout::attach_allocated_section_to_segment(const Target* target, |
| 1963 | Output_section* os) |
| 1964 | { |
| 1965 | elfcpp::Elf_Xword flags = os->flags(); |
| 1966 | gold_assert((flags & elfcpp::SHF_ALLOC) != 0); |
| 1967 | |
| 1968 | if (parameters->options().relocatable()) |
| 1969 | return; |
| 1970 | |
| 1971 | // If we have a SECTIONS clause, we can't handle the attachment to |
| 1972 | // segments until after we've seen all the sections. |
| 1973 | if (this->script_options_->saw_sections_clause()) |
| 1974 | return; |
| 1975 | |
| 1976 | gold_assert(!this->script_options_->saw_phdrs_clause()); |
| 1977 | |
| 1978 | // This output section goes into a PT_LOAD segment. |
| 1979 | |
| 1980 | elfcpp::Elf_Word seg_flags = Layout::section_flags_to_segment(flags); |
| 1981 | |
| 1982 | // If this output section's segment has extra flags that need to be set, |
| 1983 | // coming from a linker plugin, do that. |
| 1984 | seg_flags |= os->extra_segment_flags(); |
| 1985 | |
| 1986 | // Check for --section-start. |
| 1987 | uint64_t addr; |
| 1988 | bool is_address_set = parameters->options().section_start(os->name(), &addr); |
| 1989 | |
| 1990 | // In general the only thing we really care about for PT_LOAD |
| 1991 | // segments is whether or not they are writable or executable, |
| 1992 | // so that is how we search for them. |
| 1993 | // Large data sections also go into their own PT_LOAD segment. |
| 1994 | // People who need segments sorted on some other basis will |
| 1995 | // have to use a linker script. |
| 1996 | |
| 1997 | Segment_list::const_iterator p; |
| 1998 | if (!os->is_unique_segment()) |
| 1999 | { |
| 2000 | for (p = this->segment_list_.begin(); |
| 2001 | p != this->segment_list_.end(); |
| 2002 | ++p) |
| 2003 | { |
| 2004 | if ((*p)->type() != elfcpp::PT_LOAD) |
| 2005 | continue; |
| 2006 | if ((*p)->is_unique_segment()) |
| 2007 | continue; |
| 2008 | if (!parameters->options().omagic() |
| 2009 | && ((*p)->flags() & elfcpp::PF_W) != (seg_flags & elfcpp::PF_W)) |
| 2010 | continue; |
| 2011 | if ((target->isolate_execinstr() || parameters->options().rosegment()) |
| 2012 | && ((*p)->flags() & elfcpp::PF_X) != (seg_flags & elfcpp::PF_X)) |
| 2013 | continue; |
| 2014 | // If -Tbss was specified, we need to separate the data and BSS |
| 2015 | // segments. |
| 2016 | if (parameters->options().user_set_Tbss()) |
| 2017 | { |
| 2018 | if ((os->type() == elfcpp::SHT_NOBITS) |
| 2019 | == (*p)->has_any_data_sections()) |
| 2020 | continue; |
| 2021 | } |
| 2022 | if (os->is_large_data_section() && !(*p)->is_large_data_segment()) |
| 2023 | continue; |
| 2024 | |
| 2025 | if (is_address_set) |
| 2026 | { |
| 2027 | if ((*p)->are_addresses_set()) |
| 2028 | continue; |
| 2029 | |
| 2030 | (*p)->add_initial_output_data(os); |
| 2031 | (*p)->update_flags_for_output_section(seg_flags); |
| 2032 | (*p)->set_addresses(addr, addr); |
| 2033 | break; |
| 2034 | } |
| 2035 | |
| 2036 | (*p)->add_output_section_to_load(this, os, seg_flags); |
| 2037 | break; |
| 2038 | } |
| 2039 | } |
| 2040 | |
| 2041 | if (p == this->segment_list_.end() |
| 2042 | || os->is_unique_segment()) |
| 2043 | { |
| 2044 | Output_segment* oseg = this->make_output_segment(elfcpp::PT_LOAD, |
| 2045 | seg_flags); |
| 2046 | if (os->is_large_data_section()) |
| 2047 | oseg->set_is_large_data_segment(); |
| 2048 | oseg->add_output_section_to_load(this, os, seg_flags); |
| 2049 | if (is_address_set) |
| 2050 | oseg->set_addresses(addr, addr); |
| 2051 | // Check if segment should be marked unique. For segments marked |
| 2052 | // unique by linker plugins, set the new alignment if specified. |
| 2053 | if (os->is_unique_segment()) |
| 2054 | { |
| 2055 | oseg->set_is_unique_segment(); |
| 2056 | if (os->segment_alignment() != 0) |
| 2057 | oseg->set_minimum_p_align(os->segment_alignment()); |
| 2058 | } |
| 2059 | } |
| 2060 | |
| 2061 | // If we see a loadable SHT_NOTE section, we create a PT_NOTE |
| 2062 | // segment. |
| 2063 | if (os->type() == elfcpp::SHT_NOTE) |
| 2064 | { |
| 2065 | // See if we already have an equivalent PT_NOTE segment. |
| 2066 | for (p = this->segment_list_.begin(); |
| 2067 | p != segment_list_.end(); |
| 2068 | ++p) |
| 2069 | { |
| 2070 | if ((*p)->type() == elfcpp::PT_NOTE |
| 2071 | && (((*p)->flags() & elfcpp::PF_W) |
| 2072 | == (seg_flags & elfcpp::PF_W))) |
| 2073 | { |
| 2074 | (*p)->add_output_section_to_nonload(os, seg_flags); |
| 2075 | break; |
| 2076 | } |
| 2077 | } |
| 2078 | |
| 2079 | if (p == this->segment_list_.end()) |
| 2080 | { |
| 2081 | Output_segment* oseg = this->make_output_segment(elfcpp::PT_NOTE, |
| 2082 | seg_flags); |
| 2083 | oseg->add_output_section_to_nonload(os, seg_flags); |
| 2084 | } |
| 2085 | } |
| 2086 | |
| 2087 | // If we see a loadable SHF_TLS section, we create a PT_TLS |
| 2088 | // segment. There can only be one such segment. |
| 2089 | if ((flags & elfcpp::SHF_TLS) != 0) |
| 2090 | { |
| 2091 | if (this->tls_segment_ == NULL) |
| 2092 | this->make_output_segment(elfcpp::PT_TLS, seg_flags); |
| 2093 | this->tls_segment_->add_output_section_to_nonload(os, seg_flags); |
| 2094 | } |
| 2095 | |
| 2096 | // If -z relro is in effect, and we see a relro section, we create a |
| 2097 | // PT_GNU_RELRO segment. There can only be one such segment. |
| 2098 | if (os->is_relro() && parameters->options().relro()) |
| 2099 | { |
| 2100 | gold_assert(seg_flags == (elfcpp::PF_R | elfcpp::PF_W)); |
| 2101 | if (this->relro_segment_ == NULL) |
| 2102 | this->make_output_segment(elfcpp::PT_GNU_RELRO, seg_flags); |
| 2103 | this->relro_segment_->add_output_section_to_nonload(os, seg_flags); |
| 2104 | } |
| 2105 | |
| 2106 | // If we see a section named .interp, put it into a PT_INTERP |
| 2107 | // segment. This seems broken to me, but this is what GNU ld does, |
| 2108 | // and glibc expects it. |
| 2109 | if (strcmp(os->name(), ".interp") == 0 |
| 2110 | && !this->script_options_->saw_phdrs_clause()) |
| 2111 | { |
| 2112 | if (this->interp_segment_ == NULL) |
| 2113 | this->make_output_segment(elfcpp::PT_INTERP, seg_flags); |
| 2114 | else |
| 2115 | gold_warning(_("multiple '.interp' sections in input files " |
| 2116 | "may cause confusing PT_INTERP segment")); |
| 2117 | this->interp_segment_->add_output_section_to_nonload(os, seg_flags); |
| 2118 | } |
| 2119 | } |
| 2120 | |
| 2121 | // Make an output section for a script. |
| 2122 | |
| 2123 | Output_section* |
| 2124 | Layout::make_output_section_for_script( |
| 2125 | const char* name, |
| 2126 | Script_sections::Section_type section_type) |
| 2127 | { |
| 2128 | name = this->namepool_.add(name, false, NULL); |
| 2129 | elfcpp::Elf_Xword sh_flags = elfcpp::SHF_ALLOC; |
| 2130 | if (section_type == Script_sections::ST_NOLOAD) |
| 2131 | sh_flags = 0; |
| 2132 | Output_section* os = this->make_output_section(name, elfcpp::SHT_PROGBITS, |
| 2133 | sh_flags, ORDER_INVALID, |
| 2134 | false); |
| 2135 | os->set_found_in_sections_clause(); |
| 2136 | if (section_type == Script_sections::ST_NOLOAD) |
| 2137 | os->set_is_noload(); |
| 2138 | return os; |
| 2139 | } |
| 2140 | |
| 2141 | // Return the number of segments we expect to see. |
| 2142 | |
| 2143 | size_t |
| 2144 | Layout::expected_segment_count() const |
| 2145 | { |
| 2146 | size_t ret = this->segment_list_.size(); |
| 2147 | |
| 2148 | // If we didn't see a SECTIONS clause in a linker script, we should |
| 2149 | // already have the complete list of segments. Otherwise we ask the |
| 2150 | // SECTIONS clause how many segments it expects, and add in the ones |
| 2151 | // we already have (PT_GNU_STACK, PT_GNU_EH_FRAME, etc.) |
| 2152 | |
| 2153 | if (!this->script_options_->saw_sections_clause()) |
| 2154 | return ret; |
| 2155 | else |
| 2156 | { |
| 2157 | const Script_sections* ss = this->script_options_->script_sections(); |
| 2158 | return ret + ss->expected_segment_count(this); |
| 2159 | } |
| 2160 | } |
| 2161 | |
| 2162 | // Handle the .note.GNU-stack section at layout time. SEEN_GNU_STACK |
| 2163 | // is whether we saw a .note.GNU-stack section in the object file. |
| 2164 | // GNU_STACK_FLAGS is the section flags. The flags give the |
| 2165 | // protection required for stack memory. We record this in an |
| 2166 | // executable as a PT_GNU_STACK segment. If an object file does not |
| 2167 | // have a .note.GNU-stack segment, we must assume that it is an old |
| 2168 | // object. On some targets that will force an executable stack. |
| 2169 | |
| 2170 | void |
| 2171 | Layout::layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags, |
| 2172 | const Object* obj) |
| 2173 | { |
| 2174 | if (!seen_gnu_stack) |
| 2175 | { |
| 2176 | this->input_without_gnu_stack_note_ = true; |
| 2177 | if (parameters->options().warn_execstack() |
| 2178 | && parameters->target().is_default_stack_executable()) |
| 2179 | gold_warning(_("%s: missing .note.GNU-stack section" |
| 2180 | " implies executable stack"), |
| 2181 | obj->name().c_str()); |
| 2182 | } |
| 2183 | else |
| 2184 | { |
| 2185 | this->input_with_gnu_stack_note_ = true; |
| 2186 | if ((gnu_stack_flags & elfcpp::SHF_EXECINSTR) != 0) |
| 2187 | { |
| 2188 | this->input_requires_executable_stack_ = true; |
| 2189 | if (parameters->options().warn_execstack()) |
| 2190 | gold_warning(_("%s: requires executable stack"), |
| 2191 | obj->name().c_str()); |
| 2192 | } |
| 2193 | } |
| 2194 | } |
| 2195 | |
| 2196 | // Create automatic note sections. |
| 2197 | |
| 2198 | void |
| 2199 | Layout::create_notes() |
| 2200 | { |
| 2201 | this->create_gold_note(); |
| 2202 | this->create_stack_segment(); |
| 2203 | this->create_build_id(); |
| 2204 | } |
| 2205 | |
| 2206 | // Create the dynamic sections which are needed before we read the |
| 2207 | // relocs. |
| 2208 | |
| 2209 | void |
| 2210 | Layout::create_initial_dynamic_sections(Symbol_table* symtab) |
| 2211 | { |
| 2212 | if (parameters->doing_static_link()) |
| 2213 | return; |
| 2214 | |
| 2215 | this->dynamic_section_ = this->choose_output_section(NULL, ".dynamic", |
| 2216 | elfcpp::SHT_DYNAMIC, |
| 2217 | (elfcpp::SHF_ALLOC |
| 2218 | | elfcpp::SHF_WRITE), |
| 2219 | false, ORDER_RELRO, |
| 2220 | true, false, false); |
| 2221 | |
| 2222 | // A linker script may discard .dynamic, so check for NULL. |
| 2223 | if (this->dynamic_section_ != NULL) |
| 2224 | { |
| 2225 | this->dynamic_symbol_ = |
| 2226 | symtab->define_in_output_data("_DYNAMIC", NULL, |
| 2227 | Symbol_table::PREDEFINED, |
| 2228 | this->dynamic_section_, 0, 0, |
| 2229 | elfcpp::STT_OBJECT, elfcpp::STB_LOCAL, |
| 2230 | elfcpp::STV_HIDDEN, 0, false, false); |
| 2231 | |
| 2232 | this->dynamic_data_ = new Output_data_dynamic(&this->dynpool_); |
| 2233 | |
| 2234 | this->dynamic_section_->add_output_section_data(this->dynamic_data_); |
| 2235 | } |
| 2236 | } |
| 2237 | |
| 2238 | // For each output section whose name can be represented as C symbol, |
| 2239 | // define __start and __stop symbols for the section. This is a GNU |
| 2240 | // extension. |
| 2241 | |
| 2242 | void |
| 2243 | Layout::define_section_symbols(Symbol_table* symtab) |
| 2244 | { |
| 2245 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 2246 | p != this->section_list_.end(); |
| 2247 | ++p) |
| 2248 | { |
| 2249 | const char* const name = (*p)->name(); |
| 2250 | if (is_cident(name)) |
| 2251 | { |
| 2252 | const std::string name_string(name); |
| 2253 | const std::string start_name(cident_section_start_prefix |
| 2254 | + name_string); |
| 2255 | const std::string stop_name(cident_section_stop_prefix |
| 2256 | + name_string); |
| 2257 | |
| 2258 | symtab->define_in_output_data(start_name.c_str(), |
| 2259 | NULL, // version |
| 2260 | Symbol_table::PREDEFINED, |
| 2261 | *p, |
| 2262 | 0, // value |
| 2263 | 0, // symsize |
| 2264 | elfcpp::STT_NOTYPE, |
| 2265 | elfcpp::STB_GLOBAL, |
| 2266 | elfcpp::STV_PROTECTED, |
| 2267 | 0, // nonvis |
| 2268 | false, // offset_is_from_end |
| 2269 | true); // only_if_ref |
| 2270 | |
| 2271 | symtab->define_in_output_data(stop_name.c_str(), |
| 2272 | NULL, // version |
| 2273 | Symbol_table::PREDEFINED, |
| 2274 | *p, |
| 2275 | 0, // value |
| 2276 | 0, // symsize |
| 2277 | elfcpp::STT_NOTYPE, |
| 2278 | elfcpp::STB_GLOBAL, |
| 2279 | elfcpp::STV_PROTECTED, |
| 2280 | 0, // nonvis |
| 2281 | true, // offset_is_from_end |
| 2282 | true); // only_if_ref |
| 2283 | } |
| 2284 | } |
| 2285 | } |
| 2286 | |
| 2287 | // Define symbols for group signatures. |
| 2288 | |
| 2289 | void |
| 2290 | Layout::define_group_signatures(Symbol_table* symtab) |
| 2291 | { |
| 2292 | for (Group_signatures::iterator p = this->group_signatures_.begin(); |
| 2293 | p != this->group_signatures_.end(); |
| 2294 | ++p) |
| 2295 | { |
| 2296 | Symbol* sym = symtab->lookup(p->signature, NULL); |
| 2297 | if (sym != NULL) |
| 2298 | p->section->set_info_symndx(sym); |
| 2299 | else |
| 2300 | { |
| 2301 | // Force the name of the group section to the group |
| 2302 | // signature, and use the group's section symbol as the |
| 2303 | // signature symbol. |
| 2304 | if (strcmp(p->section->name(), p->signature) != 0) |
| 2305 | { |
| 2306 | const char* name = this->namepool_.add(p->signature, |
| 2307 | true, NULL); |
| 2308 | p->section->set_name(name); |
| 2309 | } |
| 2310 | p->section->set_needs_symtab_index(); |
| 2311 | p->section->set_info_section_symndx(p->section); |
| 2312 | } |
| 2313 | } |
| 2314 | |
| 2315 | this->group_signatures_.clear(); |
| 2316 | } |
| 2317 | |
| 2318 | // Find the first read-only PT_LOAD segment, creating one if |
| 2319 | // necessary. |
| 2320 | |
| 2321 | Output_segment* |
| 2322 | Layout::find_first_load_seg(const Target* target) |
| 2323 | { |
| 2324 | Output_segment* best = NULL; |
| 2325 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 2326 | p != this->segment_list_.end(); |
| 2327 | ++p) |
| 2328 | { |
| 2329 | if ((*p)->type() == elfcpp::PT_LOAD |
| 2330 | && ((*p)->flags() & elfcpp::PF_R) != 0 |
| 2331 | && (parameters->options().omagic() |
| 2332 | || ((*p)->flags() & elfcpp::PF_W) == 0) |
| 2333 | && (!target->isolate_execinstr() |
| 2334 | || ((*p)->flags() & elfcpp::PF_X) == 0)) |
| 2335 | { |
| 2336 | if (best == NULL || this->segment_precedes(*p, best)) |
| 2337 | best = *p; |
| 2338 | } |
| 2339 | } |
| 2340 | if (best != NULL) |
| 2341 | return best; |
| 2342 | |
| 2343 | gold_assert(!this->script_options_->saw_phdrs_clause()); |
| 2344 | |
| 2345 | Output_segment* load_seg = this->make_output_segment(elfcpp::PT_LOAD, |
| 2346 | elfcpp::PF_R); |
| 2347 | return load_seg; |
| 2348 | } |
| 2349 | |
| 2350 | // Save states of all current output segments. Store saved states |
| 2351 | // in SEGMENT_STATES. |
| 2352 | |
| 2353 | void |
| 2354 | Layout::save_segments(Segment_states* segment_states) |
| 2355 | { |
| 2356 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 2357 | p != this->segment_list_.end(); |
| 2358 | ++p) |
| 2359 | { |
| 2360 | Output_segment* segment = *p; |
| 2361 | // Shallow copy. |
| 2362 | Output_segment* copy = new Output_segment(*segment); |
| 2363 | (*segment_states)[segment] = copy; |
| 2364 | } |
| 2365 | } |
| 2366 | |
| 2367 | // Restore states of output segments and delete any segment not found in |
| 2368 | // SEGMENT_STATES. |
| 2369 | |
| 2370 | void |
| 2371 | Layout::restore_segments(const Segment_states* segment_states) |
| 2372 | { |
| 2373 | // Go through the segment list and remove any segment added in the |
| 2374 | // relaxation loop. |
| 2375 | this->tls_segment_ = NULL; |
| 2376 | this->relro_segment_ = NULL; |
| 2377 | Segment_list::iterator list_iter = this->segment_list_.begin(); |
| 2378 | while (list_iter != this->segment_list_.end()) |
| 2379 | { |
| 2380 | Output_segment* segment = *list_iter; |
| 2381 | Segment_states::const_iterator states_iter = |
| 2382 | segment_states->find(segment); |
| 2383 | if (states_iter != segment_states->end()) |
| 2384 | { |
| 2385 | const Output_segment* copy = states_iter->second; |
| 2386 | // Shallow copy to restore states. |
| 2387 | *segment = *copy; |
| 2388 | |
| 2389 | // Also fix up TLS and RELRO segment pointers as appropriate. |
| 2390 | if (segment->type() == elfcpp::PT_TLS) |
| 2391 | this->tls_segment_ = segment; |
| 2392 | else if (segment->type() == elfcpp::PT_GNU_RELRO) |
| 2393 | this->relro_segment_ = segment; |
| 2394 | |
| 2395 | ++list_iter; |
| 2396 | } |
| 2397 | else |
| 2398 | { |
| 2399 | list_iter = this->segment_list_.erase(list_iter); |
| 2400 | // This is a segment created during section layout. It should be |
| 2401 | // safe to remove it since we should have removed all pointers to it. |
| 2402 | delete segment; |
| 2403 | } |
| 2404 | } |
| 2405 | } |
| 2406 | |
| 2407 | // Clean up after relaxation so that sections can be laid out again. |
| 2408 | |
| 2409 | void |
| 2410 | Layout::clean_up_after_relaxation() |
| 2411 | { |
| 2412 | // Restore the segments to point state just prior to the relaxation loop. |
| 2413 | Script_sections* script_section = this->script_options_->script_sections(); |
| 2414 | script_section->release_segments(); |
| 2415 | this->restore_segments(this->segment_states_); |
| 2416 | |
| 2417 | // Reset section addresses and file offsets |
| 2418 | for (Section_list::iterator p = this->section_list_.begin(); |
| 2419 | p != this->section_list_.end(); |
| 2420 | ++p) |
| 2421 | { |
| 2422 | (*p)->restore_states(); |
| 2423 | |
| 2424 | // If an input section changes size because of relaxation, |
| 2425 | // we need to adjust the section offsets of all input sections. |
| 2426 | // after such a section. |
| 2427 | if ((*p)->section_offsets_need_adjustment()) |
| 2428 | (*p)->adjust_section_offsets(); |
| 2429 | |
| 2430 | (*p)->reset_address_and_file_offset(); |
| 2431 | } |
| 2432 | |
| 2433 | // Reset special output object address and file offsets. |
| 2434 | for (Data_list::iterator p = this->special_output_list_.begin(); |
| 2435 | p != this->special_output_list_.end(); |
| 2436 | ++p) |
| 2437 | (*p)->reset_address_and_file_offset(); |
| 2438 | |
| 2439 | // A linker script may have created some output section data objects. |
| 2440 | // They are useless now. |
| 2441 | for (Output_section_data_list::const_iterator p = |
| 2442 | this->script_output_section_data_list_.begin(); |
| 2443 | p != this->script_output_section_data_list_.end(); |
| 2444 | ++p) |
| 2445 | delete *p; |
| 2446 | this->script_output_section_data_list_.clear(); |
| 2447 | |
| 2448 | // Special-case fill output objects are recreated each time through |
| 2449 | // the relaxation loop. |
| 2450 | this->reset_relax_output(); |
| 2451 | } |
| 2452 | |
| 2453 | void |
| 2454 | Layout::reset_relax_output() |
| 2455 | { |
| 2456 | for (Data_list::const_iterator p = this->relax_output_list_.begin(); |
| 2457 | p != this->relax_output_list_.end(); |
| 2458 | ++p) |
| 2459 | delete *p; |
| 2460 | this->relax_output_list_.clear(); |
| 2461 | } |
| 2462 | |
| 2463 | // Prepare for relaxation. |
| 2464 | |
| 2465 | void |
| 2466 | Layout::prepare_for_relaxation() |
| 2467 | { |
| 2468 | // Create an relaxation debug check if in debugging mode. |
| 2469 | if (is_debugging_enabled(DEBUG_RELAXATION)) |
| 2470 | this->relaxation_debug_check_ = new Relaxation_debug_check(); |
| 2471 | |
| 2472 | // Save segment states. |
| 2473 | this->segment_states_ = new Segment_states(); |
| 2474 | this->save_segments(this->segment_states_); |
| 2475 | |
| 2476 | for(Section_list::const_iterator p = this->section_list_.begin(); |
| 2477 | p != this->section_list_.end(); |
| 2478 | ++p) |
| 2479 | (*p)->save_states(); |
| 2480 | |
| 2481 | if (is_debugging_enabled(DEBUG_RELAXATION)) |
| 2482 | this->relaxation_debug_check_->check_output_data_for_reset_values( |
| 2483 | this->section_list_, this->special_output_list_, |
| 2484 | this->relax_output_list_); |
| 2485 | |
| 2486 | // Also enable recording of output section data from scripts. |
| 2487 | this->record_output_section_data_from_script_ = true; |
| 2488 | } |
| 2489 | |
| 2490 | // If the user set the address of the text segment, that may not be |
| 2491 | // compatible with putting the segment headers and file headers into |
| 2492 | // that segment. For isolate_execinstr() targets, it's the rodata |
| 2493 | // segment rather than text where we might put the headers. |
| 2494 | static inline bool |
| 2495 | load_seg_unusable_for_headers(const Target* target) |
| 2496 | { |
| 2497 | const General_options& options = parameters->options(); |
| 2498 | if (target->isolate_execinstr()) |
| 2499 | return (options.user_set_Trodata_segment() |
| 2500 | && options.Trodata_segment() % target->abi_pagesize() != 0); |
| 2501 | else |
| 2502 | return (options.user_set_Ttext() |
| 2503 | && options.Ttext() % target->abi_pagesize() != 0); |
| 2504 | } |
| 2505 | |
| 2506 | // Relaxation loop body: If target has no relaxation, this runs only once |
| 2507 | // Otherwise, the target relaxation hook is called at the end of |
| 2508 | // each iteration. If the hook returns true, it means re-layout of |
| 2509 | // section is required. |
| 2510 | // |
| 2511 | // The number of segments created by a linking script without a PHDRS |
| 2512 | // clause may be affected by section sizes and alignments. There is |
| 2513 | // a remote chance that relaxation causes different number of PT_LOAD |
| 2514 | // segments are created and sections are attached to different segments. |
| 2515 | // Therefore, we always throw away all segments created during section |
| 2516 | // layout. In order to be able to restart the section layout, we keep |
| 2517 | // a copy of the segment list right before the relaxation loop and use |
| 2518 | // that to restore the segments. |
| 2519 | // |
| 2520 | // PASS is the current relaxation pass number. |
| 2521 | // SYMTAB is a symbol table. |
| 2522 | // PLOAD_SEG is the address of a pointer for the load segment. |
| 2523 | // PHDR_SEG is a pointer to the PHDR segment. |
| 2524 | // SEGMENT_HEADERS points to the output segment header. |
| 2525 | // FILE_HEADER points to the output file header. |
| 2526 | // PSHNDX is the address to store the output section index. |
| 2527 | |
| 2528 | off_t inline |
| 2529 | Layout::relaxation_loop_body( |
| 2530 | int pass, |
| 2531 | Target* target, |
| 2532 | Symbol_table* symtab, |
| 2533 | Output_segment** pload_seg, |
| 2534 | Output_segment* phdr_seg, |
| 2535 | Output_segment_headers* segment_headers, |
| 2536 | Output_file_header* file_header, |
| 2537 | unsigned int* pshndx) |
| 2538 | { |
| 2539 | // If this is not the first iteration, we need to clean up after |
| 2540 | // relaxation so that we can lay out the sections again. |
| 2541 | if (pass != 0) |
| 2542 | this->clean_up_after_relaxation(); |
| 2543 | |
| 2544 | // If there is a SECTIONS clause, put all the input sections into |
| 2545 | // the required order. |
| 2546 | Output_segment* load_seg; |
| 2547 | if (this->script_options_->saw_sections_clause()) |
| 2548 | load_seg = this->set_section_addresses_from_script(symtab); |
| 2549 | else if (parameters->options().relocatable()) |
| 2550 | load_seg = NULL; |
| 2551 | else |
| 2552 | load_seg = this->find_first_load_seg(target); |
| 2553 | |
| 2554 | if (parameters->options().oformat_enum() |
| 2555 | != General_options::OBJECT_FORMAT_ELF) |
| 2556 | load_seg = NULL; |
| 2557 | |
| 2558 | if (load_seg_unusable_for_headers(target)) |
| 2559 | { |
| 2560 | load_seg = NULL; |
| 2561 | phdr_seg = NULL; |
| 2562 | } |
| 2563 | |
| 2564 | gold_assert(phdr_seg == NULL |
| 2565 | || load_seg != NULL |
| 2566 | || this->script_options_->saw_sections_clause()); |
| 2567 | |
| 2568 | // If the address of the load segment we found has been set by |
| 2569 | // --section-start rather than by a script, then adjust the VMA and |
| 2570 | // LMA downward if possible to include the file and section headers. |
| 2571 | uint64_t header_gap = 0; |
| 2572 | if (load_seg != NULL |
| 2573 | && load_seg->are_addresses_set() |
| 2574 | && !this->script_options_->saw_sections_clause() |
| 2575 | && !parameters->options().relocatable()) |
| 2576 | { |
| 2577 | file_header->finalize_data_size(); |
| 2578 | segment_headers->finalize_data_size(); |
| 2579 | size_t sizeof_headers = (file_header->data_size() |
| 2580 | + segment_headers->data_size()); |
| 2581 | const uint64_t abi_pagesize = target->abi_pagesize(); |
| 2582 | uint64_t hdr_paddr = load_seg->paddr() - sizeof_headers; |
| 2583 | hdr_paddr &= ~(abi_pagesize - 1); |
| 2584 | uint64_t subtract = load_seg->paddr() - hdr_paddr; |
| 2585 | if (load_seg->paddr() < subtract || load_seg->vaddr() < subtract) |
| 2586 | load_seg = NULL; |
| 2587 | else |
| 2588 | { |
| 2589 | load_seg->set_addresses(load_seg->vaddr() - subtract, |
| 2590 | load_seg->paddr() - subtract); |
| 2591 | header_gap = subtract - sizeof_headers; |
| 2592 | } |
| 2593 | } |
| 2594 | |
| 2595 | // Lay out the segment headers. |
| 2596 | if (!parameters->options().relocatable()) |
| 2597 | { |
| 2598 | gold_assert(segment_headers != NULL); |
| 2599 | if (header_gap != 0 && load_seg != NULL) |
| 2600 | { |
| 2601 | Output_data_zero_fill* z = new Output_data_zero_fill(header_gap, 1); |
| 2602 | load_seg->add_initial_output_data(z); |
| 2603 | } |
| 2604 | if (load_seg != NULL) |
| 2605 | load_seg->add_initial_output_data(segment_headers); |
| 2606 | if (phdr_seg != NULL) |
| 2607 | phdr_seg->add_initial_output_data(segment_headers); |
| 2608 | } |
| 2609 | |
| 2610 | // Lay out the file header. |
| 2611 | if (load_seg != NULL) |
| 2612 | load_seg->add_initial_output_data(file_header); |
| 2613 | |
| 2614 | if (this->script_options_->saw_phdrs_clause() |
| 2615 | && !parameters->options().relocatable()) |
| 2616 | { |
| 2617 | // Support use of FILEHDRS and PHDRS attachments in a PHDRS |
| 2618 | // clause in a linker script. |
| 2619 | Script_sections* ss = this->script_options_->script_sections(); |
| 2620 | ss->put_headers_in_phdrs(file_header, segment_headers); |
| 2621 | } |
| 2622 | |
| 2623 | // We set the output section indexes in set_segment_offsets and |
| 2624 | // set_section_indexes. |
| 2625 | *pshndx = 1; |
| 2626 | |
| 2627 | // Set the file offsets of all the segments, and all the sections |
| 2628 | // they contain. |
| 2629 | off_t off; |
| 2630 | if (!parameters->options().relocatable()) |
| 2631 | off = this->set_segment_offsets(target, load_seg, pshndx); |
| 2632 | else |
| 2633 | off = this->set_relocatable_section_offsets(file_header, pshndx); |
| 2634 | |
| 2635 | // Verify that the dummy relaxation does not change anything. |
| 2636 | if (is_debugging_enabled(DEBUG_RELAXATION)) |
| 2637 | { |
| 2638 | if (pass == 0) |
| 2639 | this->relaxation_debug_check_->read_sections(this->section_list_); |
| 2640 | else |
| 2641 | this->relaxation_debug_check_->verify_sections(this->section_list_); |
| 2642 | } |
| 2643 | |
| 2644 | *pload_seg = load_seg; |
| 2645 | return off; |
| 2646 | } |
| 2647 | |
| 2648 | // Search the list of patterns and find the position of the given section |
| 2649 | // name in the output section. If the section name matches a glob |
| 2650 | // pattern and a non-glob name, then the non-glob position takes |
| 2651 | // precedence. Return 0 if no match is found. |
| 2652 | |
| 2653 | unsigned int |
| 2654 | Layout::find_section_order_index(const std::string& section_name) |
| 2655 | { |
| 2656 | Unordered_map<std::string, unsigned int>::iterator map_it; |
| 2657 | map_it = this->input_section_position_.find(section_name); |
| 2658 | if (map_it != this->input_section_position_.end()) |
| 2659 | return map_it->second; |
| 2660 | |
| 2661 | // Absolute match failed. Linear search the glob patterns. |
| 2662 | std::vector<std::string>::iterator it; |
| 2663 | for (it = this->input_section_glob_.begin(); |
| 2664 | it != this->input_section_glob_.end(); |
| 2665 | ++it) |
| 2666 | { |
| 2667 | if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0) |
| 2668 | { |
| 2669 | map_it = this->input_section_position_.find(*it); |
| 2670 | gold_assert(map_it != this->input_section_position_.end()); |
| 2671 | return map_it->second; |
| 2672 | } |
| 2673 | } |
| 2674 | return 0; |
| 2675 | } |
| 2676 | |
| 2677 | // Read the sequence of input sections from the file specified with |
| 2678 | // option --section-ordering-file. |
| 2679 | |
| 2680 | void |
| 2681 | Layout::read_layout_from_file() |
| 2682 | { |
| 2683 | const char* filename = parameters->options().section_ordering_file(); |
| 2684 | std::ifstream in; |
| 2685 | std::string line; |
| 2686 | |
| 2687 | in.open(filename); |
| 2688 | if (!in) |
| 2689 | gold_fatal(_("unable to open --section-ordering-file file %s: %s"), |
| 2690 | filename, strerror(errno)); |
| 2691 | |
| 2692 | std::getline(in, line); // this chops off the trailing \n, if any |
| 2693 | unsigned int position = 1; |
| 2694 | this->set_section_ordering_specified(); |
| 2695 | |
| 2696 | while (in) |
| 2697 | { |
| 2698 | if (!line.empty() && line[line.length() - 1] == '\r') // Windows |
| 2699 | line.resize(line.length() - 1); |
| 2700 | // Ignore comments, beginning with '#' |
| 2701 | if (line[0] == '#') |
| 2702 | { |
| 2703 | std::getline(in, line); |
| 2704 | continue; |
| 2705 | } |
| 2706 | this->input_section_position_[line] = position; |
| 2707 | // Store all glob patterns in a vector. |
| 2708 | if (is_wildcard_string(line.c_str())) |
| 2709 | this->input_section_glob_.push_back(line); |
| 2710 | position++; |
| 2711 | std::getline(in, line); |
| 2712 | } |
| 2713 | } |
| 2714 | |
| 2715 | // Finalize the layout. When this is called, we have created all the |
| 2716 | // output sections and all the output segments which are based on |
| 2717 | // input sections. We have several things to do, and we have to do |
| 2718 | // them in the right order, so that we get the right results correctly |
| 2719 | // and efficiently. |
| 2720 | |
| 2721 | // 1) Finalize the list of output segments and create the segment |
| 2722 | // table header. |
| 2723 | |
| 2724 | // 2) Finalize the dynamic symbol table and associated sections. |
| 2725 | |
| 2726 | // 3) Determine the final file offset of all the output segments. |
| 2727 | |
| 2728 | // 4) Determine the final file offset of all the SHF_ALLOC output |
| 2729 | // sections. |
| 2730 | |
| 2731 | // 5) Create the symbol table sections and the section name table |
| 2732 | // section. |
| 2733 | |
| 2734 | // 6) Finalize the symbol table: set symbol values to their final |
| 2735 | // value and make a final determination of which symbols are going |
| 2736 | // into the output symbol table. |
| 2737 | |
| 2738 | // 7) Create the section table header. |
| 2739 | |
| 2740 | // 8) Determine the final file offset of all the output sections which |
| 2741 | // are not SHF_ALLOC, including the section table header. |
| 2742 | |
| 2743 | // 9) Finalize the ELF file header. |
| 2744 | |
| 2745 | // This function returns the size of the output file. |
| 2746 | |
| 2747 | off_t |
| 2748 | Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab, |
| 2749 | Target* target, const Task* task) |
| 2750 | { |
| 2751 | unsigned int local_dynamic_count = 0; |
| 2752 | unsigned int forced_local_dynamic_count = 0; |
| 2753 | |
| 2754 | target->finalize_sections(this, input_objects, symtab); |
| 2755 | |
| 2756 | this->count_local_symbols(task, input_objects); |
| 2757 | |
| 2758 | this->link_stabs_sections(); |
| 2759 | |
| 2760 | Output_segment* phdr_seg = NULL; |
| 2761 | if (!parameters->options().relocatable() && !parameters->doing_static_link()) |
| 2762 | { |
| 2763 | // There was a dynamic object in the link. We need to create |
| 2764 | // some information for the dynamic linker. |
| 2765 | |
| 2766 | // Create the PT_PHDR segment which will hold the program |
| 2767 | // headers. |
| 2768 | if (!this->script_options_->saw_phdrs_clause()) |
| 2769 | phdr_seg = this->make_output_segment(elfcpp::PT_PHDR, elfcpp::PF_R); |
| 2770 | |
| 2771 | // Create the dynamic symbol table, including the hash table. |
| 2772 | Output_section* dynstr; |
| 2773 | std::vector<Symbol*> dynamic_symbols; |
| 2774 | Versions versions(*this->script_options()->version_script_info(), |
| 2775 | &this->dynpool_); |
| 2776 | this->create_dynamic_symtab(input_objects, symtab, &dynstr, |
| 2777 | &local_dynamic_count, |
| 2778 | &forced_local_dynamic_count, |
| 2779 | &dynamic_symbols, |
| 2780 | &versions); |
| 2781 | |
| 2782 | // Create the .interp section to hold the name of the |
| 2783 | // interpreter, and put it in a PT_INTERP segment. Don't do it |
| 2784 | // if we saw a .interp section in an input file. |
| 2785 | if ((!parameters->options().shared() |
| 2786 | || parameters->options().dynamic_linker() != NULL) |
| 2787 | && this->interp_segment_ == NULL) |
| 2788 | this->create_interp(target); |
| 2789 | |
| 2790 | // Finish the .dynamic section to hold the dynamic data, and put |
| 2791 | // it in a PT_DYNAMIC segment. |
| 2792 | this->finish_dynamic_section(input_objects, symtab); |
| 2793 | |
| 2794 | // We should have added everything we need to the dynamic string |
| 2795 | // table. |
| 2796 | this->dynpool_.set_string_offsets(); |
| 2797 | |
| 2798 | // Create the version sections. We can't do this until the |
| 2799 | // dynamic string table is complete. |
| 2800 | this->create_version_sections(&versions, symtab, |
| 2801 | (local_dynamic_count |
| 2802 | + forced_local_dynamic_count), |
| 2803 | dynamic_symbols, dynstr); |
| 2804 | |
| 2805 | // Set the size of the _DYNAMIC symbol. We can't do this until |
| 2806 | // after we call create_version_sections. |
| 2807 | this->set_dynamic_symbol_size(symtab); |
| 2808 | } |
| 2809 | |
| 2810 | // Create segment headers. |
| 2811 | Output_segment_headers* segment_headers = |
| 2812 | (parameters->options().relocatable() |
| 2813 | ? NULL |
| 2814 | : new Output_segment_headers(this->segment_list_)); |
| 2815 | |
| 2816 | // Lay out the file header. |
| 2817 | Output_file_header* file_header = new Output_file_header(target, symtab, |
| 2818 | segment_headers); |
| 2819 | |
| 2820 | this->special_output_list_.push_back(file_header); |
| 2821 | if (segment_headers != NULL) |
| 2822 | this->special_output_list_.push_back(segment_headers); |
| 2823 | |
| 2824 | // Find approriate places for orphan output sections if we are using |
| 2825 | // a linker script. |
| 2826 | if (this->script_options_->saw_sections_clause()) |
| 2827 | this->place_orphan_sections_in_script(); |
| 2828 | |
| 2829 | Output_segment* load_seg; |
| 2830 | off_t off; |
| 2831 | unsigned int shndx; |
| 2832 | int pass = 0; |
| 2833 | |
| 2834 | // Take a snapshot of the section layout as needed. |
| 2835 | if (target->may_relax()) |
| 2836 | this->prepare_for_relaxation(); |
| 2837 | |
| 2838 | // Run the relaxation loop to lay out sections. |
| 2839 | do |
| 2840 | { |
| 2841 | off = this->relaxation_loop_body(pass, target, symtab, &load_seg, |
| 2842 | phdr_seg, segment_headers, file_header, |
| 2843 | &shndx); |
| 2844 | pass++; |
| 2845 | } |
| 2846 | while (target->may_relax() |
| 2847 | && target->relax(pass, input_objects, symtab, this, task)); |
| 2848 | |
| 2849 | // If there is a load segment that contains the file and program headers, |
| 2850 | // provide a symbol __ehdr_start pointing there. |
| 2851 | // A program can use this to examine itself robustly. |
| 2852 | Symbol *ehdr_start = symtab->lookup("__ehdr_start"); |
| 2853 | if (ehdr_start != NULL && ehdr_start->is_predefined()) |
| 2854 | { |
| 2855 | if (load_seg != NULL) |
| 2856 | ehdr_start->set_output_segment(load_seg, Symbol::SEGMENT_START); |
| 2857 | else |
| 2858 | ehdr_start->set_undefined(); |
| 2859 | } |
| 2860 | |
| 2861 | // Set the file offsets of all the non-data sections we've seen so |
| 2862 | // far which don't have to wait for the input sections. We need |
| 2863 | // this in order to finalize local symbols in non-allocated |
| 2864 | // sections. |
| 2865 | off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS); |
| 2866 | |
| 2867 | // Set the section indexes of all unallocated sections seen so far, |
| 2868 | // in case any of them are somehow referenced by a symbol. |
| 2869 | shndx = this->set_section_indexes(shndx); |
| 2870 | |
| 2871 | // Create the symbol table sections. |
| 2872 | this->create_symtab_sections(input_objects, symtab, shndx, &off, |
| 2873 | local_dynamic_count); |
| 2874 | if (!parameters->doing_static_link()) |
| 2875 | this->assign_local_dynsym_offsets(input_objects); |
| 2876 | |
| 2877 | // Process any symbol assignments from a linker script. This must |
| 2878 | // be called after the symbol table has been finalized. |
| 2879 | this->script_options_->finalize_symbols(symtab, this); |
| 2880 | |
| 2881 | // Create the incremental inputs sections. |
| 2882 | if (this->incremental_inputs_) |
| 2883 | { |
| 2884 | this->incremental_inputs_->finalize(); |
| 2885 | this->create_incremental_info_sections(symtab); |
| 2886 | } |
| 2887 | |
| 2888 | // Create the .shstrtab section. |
| 2889 | Output_section* shstrtab_section = this->create_shstrtab(); |
| 2890 | |
| 2891 | // Set the file offsets of the rest of the non-data sections which |
| 2892 | // don't have to wait for the input sections. |
| 2893 | off = this->set_section_offsets(off, BEFORE_INPUT_SECTIONS_PASS); |
| 2894 | |
| 2895 | // Now that all sections have been created, set the section indexes |
| 2896 | // for any sections which haven't been done yet. |
| 2897 | shndx = this->set_section_indexes(shndx); |
| 2898 | |
| 2899 | // Create the section table header. |
| 2900 | this->create_shdrs(shstrtab_section, &off); |
| 2901 | |
| 2902 | // If there are no sections which require postprocessing, we can |
| 2903 | // handle the section names now, and avoid a resize later. |
| 2904 | if (!this->any_postprocessing_sections_) |
| 2905 | { |
| 2906 | off = this->set_section_offsets(off, |
| 2907 | POSTPROCESSING_SECTIONS_PASS); |
| 2908 | off = |
| 2909 | this->set_section_offsets(off, |
| 2910 | STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS); |
| 2911 | } |
| 2912 | |
| 2913 | file_header->set_section_info(this->section_headers_, shstrtab_section); |
| 2914 | |
| 2915 | // Now we know exactly where everything goes in the output file |
| 2916 | // (except for non-allocated sections which require postprocessing). |
| 2917 | Output_data::layout_complete(); |
| 2918 | |
| 2919 | this->output_file_size_ = off; |
| 2920 | |
| 2921 | return off; |
| 2922 | } |
| 2923 | |
| 2924 | // Create a note header following the format defined in the ELF ABI. |
| 2925 | // NAME is the name, NOTE_TYPE is the type, SECTION_NAME is the name |
| 2926 | // of the section to create, DESCSZ is the size of the descriptor. |
| 2927 | // ALLOCATE is true if the section should be allocated in memory. |
| 2928 | // This returns the new note section. It sets *TRAILING_PADDING to |
| 2929 | // the number of trailing zero bytes required. |
| 2930 | |
| 2931 | Output_section* |
| 2932 | Layout::create_note(const char* name, int note_type, |
| 2933 | const char* section_name, size_t descsz, |
| 2934 | bool allocate, size_t* trailing_padding) |
| 2935 | { |
| 2936 | // Authorities all agree that the values in a .note field should |
| 2937 | // be aligned on 4-byte boundaries for 32-bit binaries. However, |
| 2938 | // they differ on what the alignment is for 64-bit binaries. |
| 2939 | // The GABI says unambiguously they take 8-byte alignment: |
| 2940 | // http://sco.com/developers/gabi/latest/ch5.pheader.html#note_section |
| 2941 | // Other documentation says alignment should always be 4 bytes: |
| 2942 | // http://www.netbsd.org/docs/kernel/elf-notes.html#note-format |
| 2943 | // GNU ld and GNU readelf both support the latter (at least as of |
| 2944 | // version 2.16.91), and glibc always generates the latter for |
| 2945 | // .note.ABI-tag (as of version 1.6), so that's the one we go with |
| 2946 | // here. |
| 2947 | #ifdef GABI_FORMAT_FOR_DOTNOTE_SECTION // This is not defined by default. |
| 2948 | const int size = parameters->target().get_size(); |
| 2949 | #else |
| 2950 | const int size = 32; |
| 2951 | #endif |
| 2952 | |
| 2953 | // The contents of the .note section. |
| 2954 | size_t namesz = strlen(name) + 1; |
| 2955 | size_t aligned_namesz = align_address(namesz, size / 8); |
| 2956 | size_t aligned_descsz = align_address(descsz, size / 8); |
| 2957 | |
| 2958 | size_t notehdrsz = 3 * (size / 8) + aligned_namesz; |
| 2959 | |
| 2960 | unsigned char* buffer = new unsigned char[notehdrsz]; |
| 2961 | memset(buffer, 0, notehdrsz); |
| 2962 | |
| 2963 | bool is_big_endian = parameters->target().is_big_endian(); |
| 2964 | |
| 2965 | if (size == 32) |
| 2966 | { |
| 2967 | if (!is_big_endian) |
| 2968 | { |
| 2969 | elfcpp::Swap<32, false>::writeval(buffer, namesz); |
| 2970 | elfcpp::Swap<32, false>::writeval(buffer + 4, descsz); |
| 2971 | elfcpp::Swap<32, false>::writeval(buffer + 8, note_type); |
| 2972 | } |
| 2973 | else |
| 2974 | { |
| 2975 | elfcpp::Swap<32, true>::writeval(buffer, namesz); |
| 2976 | elfcpp::Swap<32, true>::writeval(buffer + 4, descsz); |
| 2977 | elfcpp::Swap<32, true>::writeval(buffer + 8, note_type); |
| 2978 | } |
| 2979 | } |
| 2980 | else if (size == 64) |
| 2981 | { |
| 2982 | if (!is_big_endian) |
| 2983 | { |
| 2984 | elfcpp::Swap<64, false>::writeval(buffer, namesz); |
| 2985 | elfcpp::Swap<64, false>::writeval(buffer + 8, descsz); |
| 2986 | elfcpp::Swap<64, false>::writeval(buffer + 16, note_type); |
| 2987 | } |
| 2988 | else |
| 2989 | { |
| 2990 | elfcpp::Swap<64, true>::writeval(buffer, namesz); |
| 2991 | elfcpp::Swap<64, true>::writeval(buffer + 8, descsz); |
| 2992 | elfcpp::Swap<64, true>::writeval(buffer + 16, note_type); |
| 2993 | } |
| 2994 | } |
| 2995 | else |
| 2996 | gold_unreachable(); |
| 2997 | |
| 2998 | memcpy(buffer + 3 * (size / 8), name, namesz); |
| 2999 | |
| 3000 | elfcpp::Elf_Xword flags = 0; |
| 3001 | Output_section_order order = ORDER_INVALID; |
| 3002 | if (allocate) |
| 3003 | { |
| 3004 | flags = elfcpp::SHF_ALLOC; |
| 3005 | order = ORDER_RO_NOTE; |
| 3006 | } |
| 3007 | Output_section* os = this->choose_output_section(NULL, section_name, |
| 3008 | elfcpp::SHT_NOTE, |
| 3009 | flags, false, order, false, |
| 3010 | false, true); |
| 3011 | if (os == NULL) |
| 3012 | return NULL; |
| 3013 | |
| 3014 | Output_section_data* posd = new Output_data_const_buffer(buffer, notehdrsz, |
| 3015 | size / 8, |
| 3016 | "** note header"); |
| 3017 | os->add_output_section_data(posd); |
| 3018 | |
| 3019 | *trailing_padding = aligned_descsz - descsz; |
| 3020 | |
| 3021 | return os; |
| 3022 | } |
| 3023 | |
| 3024 | // For an executable or shared library, create a note to record the |
| 3025 | // version of gold used to create the binary. |
| 3026 | |
| 3027 | void |
| 3028 | Layout::create_gold_note() |
| 3029 | { |
| 3030 | if (parameters->options().relocatable() |
| 3031 | || parameters->incremental_update()) |
| 3032 | return; |
| 3033 | |
| 3034 | std::string desc = std::string("gold ") + gold::get_version_string(); |
| 3035 | |
| 3036 | size_t trailing_padding; |
| 3037 | Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_GOLD_VERSION, |
| 3038 | ".note.gnu.gold-version", desc.size(), |
| 3039 | false, &trailing_padding); |
| 3040 | if (os == NULL) |
| 3041 | return; |
| 3042 | |
| 3043 | Output_section_data* posd = new Output_data_const(desc, 4); |
| 3044 | os->add_output_section_data(posd); |
| 3045 | |
| 3046 | if (trailing_padding > 0) |
| 3047 | { |
| 3048 | posd = new Output_data_zero_fill(trailing_padding, 0); |
| 3049 | os->add_output_section_data(posd); |
| 3050 | } |
| 3051 | } |
| 3052 | |
| 3053 | // Record whether the stack should be executable. This can be set |
| 3054 | // from the command line using the -z execstack or -z noexecstack |
| 3055 | // options. Otherwise, if any input file has a .note.GNU-stack |
| 3056 | // section with the SHF_EXECINSTR flag set, the stack should be |
| 3057 | // executable. Otherwise, if at least one input file a |
| 3058 | // .note.GNU-stack section, and some input file has no .note.GNU-stack |
| 3059 | // section, we use the target default for whether the stack should be |
| 3060 | // executable. If -z stack-size was used to set a p_memsz value for |
| 3061 | // PT_GNU_STACK, we generate the segment regardless. Otherwise, we |
| 3062 | // don't generate a stack note. When generating a object file, we |
| 3063 | // create a .note.GNU-stack section with the appropriate marking. |
| 3064 | // When generating an executable or shared library, we create a |
| 3065 | // PT_GNU_STACK segment. |
| 3066 | |
| 3067 | void |
| 3068 | Layout::create_stack_segment() |
| 3069 | { |
| 3070 | bool is_stack_executable; |
| 3071 | if (parameters->options().is_execstack_set()) |
| 3072 | { |
| 3073 | is_stack_executable = parameters->options().is_stack_executable(); |
| 3074 | if (!is_stack_executable |
| 3075 | && this->input_requires_executable_stack_ |
| 3076 | && parameters->options().warn_execstack()) |
| 3077 | gold_warning(_("one or more inputs require executable stack, " |
| 3078 | "but -z noexecstack was given")); |
| 3079 | } |
| 3080 | else if (!this->input_with_gnu_stack_note_ |
| 3081 | && (!parameters->options().user_set_stack_size() |
| 3082 | || parameters->options().relocatable())) |
| 3083 | return; |
| 3084 | else |
| 3085 | { |
| 3086 | if (this->input_requires_executable_stack_) |
| 3087 | is_stack_executable = true; |
| 3088 | else if (this->input_without_gnu_stack_note_) |
| 3089 | is_stack_executable = |
| 3090 | parameters->target().is_default_stack_executable(); |
| 3091 | else |
| 3092 | is_stack_executable = false; |
| 3093 | } |
| 3094 | |
| 3095 | if (parameters->options().relocatable()) |
| 3096 | { |
| 3097 | const char* name = this->namepool_.add(".note.GNU-stack", false, NULL); |
| 3098 | elfcpp::Elf_Xword flags = 0; |
| 3099 | if (is_stack_executable) |
| 3100 | flags |= elfcpp::SHF_EXECINSTR; |
| 3101 | this->make_output_section(name, elfcpp::SHT_PROGBITS, flags, |
| 3102 | ORDER_INVALID, false); |
| 3103 | } |
| 3104 | else |
| 3105 | { |
| 3106 | if (this->script_options_->saw_phdrs_clause()) |
| 3107 | return; |
| 3108 | int flags = elfcpp::PF_R | elfcpp::PF_W; |
| 3109 | if (is_stack_executable) |
| 3110 | flags |= elfcpp::PF_X; |
| 3111 | Output_segment* seg = |
| 3112 | this->make_output_segment(elfcpp::PT_GNU_STACK, flags); |
| 3113 | seg->set_size(parameters->options().stack_size()); |
| 3114 | // BFD lets targets override this default alignment, but the only |
| 3115 | // targets that do so are ones that Gold does not support so far. |
| 3116 | seg->set_minimum_p_align(16); |
| 3117 | } |
| 3118 | } |
| 3119 | |
| 3120 | // If --build-id was used, set up the build ID note. |
| 3121 | |
| 3122 | void |
| 3123 | Layout::create_build_id() |
| 3124 | { |
| 3125 | if (!parameters->options().user_set_build_id()) |
| 3126 | return; |
| 3127 | |
| 3128 | const char* style = parameters->options().build_id(); |
| 3129 | if (strcmp(style, "none") == 0) |
| 3130 | return; |
| 3131 | |
| 3132 | // Set DESCSZ to the size of the note descriptor. When possible, |
| 3133 | // set DESC to the note descriptor contents. |
| 3134 | size_t descsz; |
| 3135 | std::string desc; |
| 3136 | if (strcmp(style, "md5") == 0) |
| 3137 | descsz = 128 / 8; |
| 3138 | else if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) |
| 3139 | descsz = 160 / 8; |
| 3140 | else if (strcmp(style, "uuid") == 0) |
| 3141 | { |
| 3142 | #ifndef __MINGW32__ |
| 3143 | const size_t uuidsz = 128 / 8; |
| 3144 | |
| 3145 | char buffer[uuidsz]; |
| 3146 | memset(buffer, 0, uuidsz); |
| 3147 | |
| 3148 | int descriptor = open_descriptor(-1, "/dev/urandom", O_RDONLY); |
| 3149 | if (descriptor < 0) |
| 3150 | gold_error(_("--build-id=uuid failed: could not open /dev/urandom: %s"), |
| 3151 | strerror(errno)); |
| 3152 | else |
| 3153 | { |
| 3154 | ssize_t got = ::read(descriptor, buffer, uuidsz); |
| 3155 | release_descriptor(descriptor, true); |
| 3156 | if (got < 0) |
| 3157 | gold_error(_("/dev/urandom: read failed: %s"), strerror(errno)); |
| 3158 | else if (static_cast<size_t>(got) != uuidsz) |
| 3159 | gold_error(_("/dev/urandom: expected %zu bytes, got %zd bytes"), |
| 3160 | uuidsz, got); |
| 3161 | } |
| 3162 | |
| 3163 | desc.assign(buffer, uuidsz); |
| 3164 | descsz = uuidsz; |
| 3165 | #else // __MINGW32__ |
| 3166 | UUID uuid; |
| 3167 | typedef RPC_STATUS (RPC_ENTRY *UuidCreateFn)(UUID *Uuid); |
| 3168 | |
| 3169 | HMODULE rpc_library = LoadLibrary("rpcrt4.dll"); |
| 3170 | if (!rpc_library) |
| 3171 | gold_error(_("--build-id=uuid failed: could not load rpcrt4.dll")); |
| 3172 | else |
| 3173 | { |
| 3174 | UuidCreateFn uuid_create = reinterpret_cast<UuidCreateFn>( |
| 3175 | GetProcAddress(rpc_library, "UuidCreate")); |
| 3176 | if (!uuid_create) |
| 3177 | gold_error(_("--build-id=uuid failed: could not find UuidCreate")); |
| 3178 | else if (uuid_create(&uuid) != RPC_S_OK) |
| 3179 | gold_error(_("__build_id=uuid failed: call UuidCreate() failed")); |
| 3180 | FreeLibrary(rpc_library); |
| 3181 | } |
| 3182 | desc.assign(reinterpret_cast<const char *>(&uuid), sizeof(UUID)); |
| 3183 | descsz = sizeof(UUID); |
| 3184 | #endif // __MINGW32__ |
| 3185 | } |
| 3186 | else if (strncmp(style, "0x", 2) == 0) |
| 3187 | { |
| 3188 | hex_init(); |
| 3189 | const char* p = style + 2; |
| 3190 | while (*p != '\0') |
| 3191 | { |
| 3192 | if (hex_p(p[0]) && hex_p(p[1])) |
| 3193 | { |
| 3194 | char c = (hex_value(p[0]) << 4) | hex_value(p[1]); |
| 3195 | desc += c; |
| 3196 | p += 2; |
| 3197 | } |
| 3198 | else if (*p == '-' || *p == ':') |
| 3199 | ++p; |
| 3200 | else |
| 3201 | gold_fatal(_("--build-id argument '%s' not a valid hex number"), |
| 3202 | style); |
| 3203 | } |
| 3204 | descsz = desc.size(); |
| 3205 | } |
| 3206 | else |
| 3207 | gold_fatal(_("unrecognized --build-id argument '%s'"), style); |
| 3208 | |
| 3209 | // Create the note. |
| 3210 | size_t trailing_padding; |
| 3211 | Output_section* os = this->create_note("GNU", elfcpp::NT_GNU_BUILD_ID, |
| 3212 | ".note.gnu.build-id", descsz, true, |
| 3213 | &trailing_padding); |
| 3214 | if (os == NULL) |
| 3215 | return; |
| 3216 | |
| 3217 | if (!desc.empty()) |
| 3218 | { |
| 3219 | // We know the value already, so we fill it in now. |
| 3220 | gold_assert(desc.size() == descsz); |
| 3221 | |
| 3222 | Output_section_data* posd = new Output_data_const(desc, 4); |
| 3223 | os->add_output_section_data(posd); |
| 3224 | |
| 3225 | if (trailing_padding != 0) |
| 3226 | { |
| 3227 | posd = new Output_data_zero_fill(trailing_padding, 0); |
| 3228 | os->add_output_section_data(posd); |
| 3229 | } |
| 3230 | } |
| 3231 | else |
| 3232 | { |
| 3233 | // We need to compute a checksum after we have completed the |
| 3234 | // link. |
| 3235 | gold_assert(trailing_padding == 0); |
| 3236 | this->build_id_note_ = new Output_data_zero_fill(descsz, 4); |
| 3237 | os->add_output_section_data(this->build_id_note_); |
| 3238 | } |
| 3239 | } |
| 3240 | |
| 3241 | // If we have both .stabXX and .stabXXstr sections, then the sh_link |
| 3242 | // field of the former should point to the latter. I'm not sure who |
| 3243 | // started this, but the GNU linker does it, and some tools depend |
| 3244 | // upon it. |
| 3245 | |
| 3246 | void |
| 3247 | Layout::link_stabs_sections() |
| 3248 | { |
| 3249 | if (!this->have_stabstr_section_) |
| 3250 | return; |
| 3251 | |
| 3252 | for (Section_list::iterator p = this->section_list_.begin(); |
| 3253 | p != this->section_list_.end(); |
| 3254 | ++p) |
| 3255 | { |
| 3256 | if ((*p)->type() != elfcpp::SHT_STRTAB) |
| 3257 | continue; |
| 3258 | |
| 3259 | const char* name = (*p)->name(); |
| 3260 | if (strncmp(name, ".stab", 5) != 0) |
| 3261 | continue; |
| 3262 | |
| 3263 | size_t len = strlen(name); |
| 3264 | if (strcmp(name + len - 3, "str") != 0) |
| 3265 | continue; |
| 3266 | |
| 3267 | std::string stab_name(name, len - 3); |
| 3268 | Output_section* stab_sec; |
| 3269 | stab_sec = this->find_output_section(stab_name.c_str()); |
| 3270 | if (stab_sec != NULL) |
| 3271 | stab_sec->set_link_section(*p); |
| 3272 | } |
| 3273 | } |
| 3274 | |
| 3275 | // Create .gnu_incremental_inputs and related sections needed |
| 3276 | // for the next run of incremental linking to check what has changed. |
| 3277 | |
| 3278 | void |
| 3279 | Layout::create_incremental_info_sections(Symbol_table* symtab) |
| 3280 | { |
| 3281 | Incremental_inputs* incr = this->incremental_inputs_; |
| 3282 | |
| 3283 | gold_assert(incr != NULL); |
| 3284 | |
| 3285 | // Create the .gnu_incremental_inputs, _symtab, and _relocs input sections. |
| 3286 | incr->create_data_sections(symtab); |
| 3287 | |
| 3288 | // Add the .gnu_incremental_inputs section. |
| 3289 | const char* incremental_inputs_name = |
| 3290 | this->namepool_.add(".gnu_incremental_inputs", false, NULL); |
| 3291 | Output_section* incremental_inputs_os = |
| 3292 | this->make_output_section(incremental_inputs_name, |
| 3293 | elfcpp::SHT_GNU_INCREMENTAL_INPUTS, 0, |
| 3294 | ORDER_INVALID, false); |
| 3295 | incremental_inputs_os->add_output_section_data(incr->inputs_section()); |
| 3296 | |
| 3297 | // Add the .gnu_incremental_symtab section. |
| 3298 | const char* incremental_symtab_name = |
| 3299 | this->namepool_.add(".gnu_incremental_symtab", false, NULL); |
| 3300 | Output_section* incremental_symtab_os = |
| 3301 | this->make_output_section(incremental_symtab_name, |
| 3302 | elfcpp::SHT_GNU_INCREMENTAL_SYMTAB, 0, |
| 3303 | ORDER_INVALID, false); |
| 3304 | incremental_symtab_os->add_output_section_data(incr->symtab_section()); |
| 3305 | incremental_symtab_os->set_entsize(4); |
| 3306 | |
| 3307 | // Add the .gnu_incremental_relocs section. |
| 3308 | const char* incremental_relocs_name = |
| 3309 | this->namepool_.add(".gnu_incremental_relocs", false, NULL); |
| 3310 | Output_section* incremental_relocs_os = |
| 3311 | this->make_output_section(incremental_relocs_name, |
| 3312 | elfcpp::SHT_GNU_INCREMENTAL_RELOCS, 0, |
| 3313 | ORDER_INVALID, false); |
| 3314 | incremental_relocs_os->add_output_section_data(incr->relocs_section()); |
| 3315 | incremental_relocs_os->set_entsize(incr->relocs_entsize()); |
| 3316 | |
| 3317 | // Add the .gnu_incremental_got_plt section. |
| 3318 | const char* incremental_got_plt_name = |
| 3319 | this->namepool_.add(".gnu_incremental_got_plt", false, NULL); |
| 3320 | Output_section* incremental_got_plt_os = |
| 3321 | this->make_output_section(incremental_got_plt_name, |
| 3322 | elfcpp::SHT_GNU_INCREMENTAL_GOT_PLT, 0, |
| 3323 | ORDER_INVALID, false); |
| 3324 | incremental_got_plt_os->add_output_section_data(incr->got_plt_section()); |
| 3325 | |
| 3326 | // Add the .gnu_incremental_strtab section. |
| 3327 | const char* incremental_strtab_name = |
| 3328 | this->namepool_.add(".gnu_incremental_strtab", false, NULL); |
| 3329 | Output_section* incremental_strtab_os = this->make_output_section(incremental_strtab_name, |
| 3330 | elfcpp::SHT_STRTAB, 0, |
| 3331 | ORDER_INVALID, false); |
| 3332 | Output_data_strtab* strtab_data = |
| 3333 | new Output_data_strtab(incr->get_stringpool()); |
| 3334 | incremental_strtab_os->add_output_section_data(strtab_data); |
| 3335 | |
| 3336 | incremental_inputs_os->set_after_input_sections(); |
| 3337 | incremental_symtab_os->set_after_input_sections(); |
| 3338 | incremental_relocs_os->set_after_input_sections(); |
| 3339 | incremental_got_plt_os->set_after_input_sections(); |
| 3340 | |
| 3341 | incremental_inputs_os->set_link_section(incremental_strtab_os); |
| 3342 | incremental_symtab_os->set_link_section(incremental_inputs_os); |
| 3343 | incremental_relocs_os->set_link_section(incremental_inputs_os); |
| 3344 | incremental_got_plt_os->set_link_section(incremental_inputs_os); |
| 3345 | } |
| 3346 | |
| 3347 | // Return whether SEG1 should be before SEG2 in the output file. This |
| 3348 | // is based entirely on the segment type and flags. When this is |
| 3349 | // called the segment addresses have normally not yet been set. |
| 3350 | |
| 3351 | bool |
| 3352 | Layout::segment_precedes(const Output_segment* seg1, |
| 3353 | const Output_segment* seg2) |
| 3354 | { |
| 3355 | // In order to produce a stable ordering if we're called with the same pointer |
| 3356 | // return false. |
| 3357 | if (seg1 == seg2) |
| 3358 | return false; |
| 3359 | |
| 3360 | elfcpp::Elf_Word type1 = seg1->type(); |
| 3361 | elfcpp::Elf_Word type2 = seg2->type(); |
| 3362 | |
| 3363 | // The single PT_PHDR segment is required to precede any loadable |
| 3364 | // segment. We simply make it always first. |
| 3365 | if (type1 == elfcpp::PT_PHDR) |
| 3366 | { |
| 3367 | gold_assert(type2 != elfcpp::PT_PHDR); |
| 3368 | return true; |
| 3369 | } |
| 3370 | if (type2 == elfcpp::PT_PHDR) |
| 3371 | return false; |
| 3372 | |
| 3373 | // The single PT_INTERP segment is required to precede any loadable |
| 3374 | // segment. We simply make it always second. |
| 3375 | if (type1 == elfcpp::PT_INTERP) |
| 3376 | { |
| 3377 | gold_assert(type2 != elfcpp::PT_INTERP); |
| 3378 | return true; |
| 3379 | } |
| 3380 | if (type2 == elfcpp::PT_INTERP) |
| 3381 | return false; |
| 3382 | |
| 3383 | // We then put PT_LOAD segments before any other segments. |
| 3384 | if (type1 == elfcpp::PT_LOAD && type2 != elfcpp::PT_LOAD) |
| 3385 | return true; |
| 3386 | if (type2 == elfcpp::PT_LOAD && type1 != elfcpp::PT_LOAD) |
| 3387 | return false; |
| 3388 | |
| 3389 | // We put the PT_TLS segment last except for the PT_GNU_RELRO |
| 3390 | // segment, because that is where the dynamic linker expects to find |
| 3391 | // it (this is just for efficiency; other positions would also work |
| 3392 | // correctly). |
| 3393 | if (type1 == elfcpp::PT_TLS |
| 3394 | && type2 != elfcpp::PT_TLS |
| 3395 | && type2 != elfcpp::PT_GNU_RELRO) |
| 3396 | return false; |
| 3397 | if (type2 == elfcpp::PT_TLS |
| 3398 | && type1 != elfcpp::PT_TLS |
| 3399 | && type1 != elfcpp::PT_GNU_RELRO) |
| 3400 | return true; |
| 3401 | |
| 3402 | // We put the PT_GNU_RELRO segment last, because that is where the |
| 3403 | // dynamic linker expects to find it (as with PT_TLS, this is just |
| 3404 | // for efficiency). |
| 3405 | if (type1 == elfcpp::PT_GNU_RELRO && type2 != elfcpp::PT_GNU_RELRO) |
| 3406 | return false; |
| 3407 | if (type2 == elfcpp::PT_GNU_RELRO && type1 != elfcpp::PT_GNU_RELRO) |
| 3408 | return true; |
| 3409 | |
| 3410 | const elfcpp::Elf_Word flags1 = seg1->flags(); |
| 3411 | const elfcpp::Elf_Word flags2 = seg2->flags(); |
| 3412 | |
| 3413 | // The order of non-PT_LOAD segments is unimportant. We simply sort |
| 3414 | // by the numeric segment type and flags values. There should not |
| 3415 | // be more than one segment with the same type and flags, except |
| 3416 | // when a linker script specifies such. |
| 3417 | if (type1 != elfcpp::PT_LOAD) |
| 3418 | { |
| 3419 | if (type1 != type2) |
| 3420 | return type1 < type2; |
| 3421 | gold_assert(flags1 != flags2 |
| 3422 | || this->script_options_->saw_phdrs_clause()); |
| 3423 | return flags1 < flags2; |
| 3424 | } |
| 3425 | |
| 3426 | // If the addresses are set already, sort by load address. |
| 3427 | if (seg1->are_addresses_set()) |
| 3428 | { |
| 3429 | if (!seg2->are_addresses_set()) |
| 3430 | return true; |
| 3431 | |
| 3432 | unsigned int section_count1 = seg1->output_section_count(); |
| 3433 | unsigned int section_count2 = seg2->output_section_count(); |
| 3434 | if (section_count1 == 0 && section_count2 > 0) |
| 3435 | return true; |
| 3436 | if (section_count1 > 0 && section_count2 == 0) |
| 3437 | return false; |
| 3438 | |
| 3439 | uint64_t paddr1 = (seg1->are_addresses_set() |
| 3440 | ? seg1->paddr() |
| 3441 | : seg1->first_section_load_address()); |
| 3442 | uint64_t paddr2 = (seg2->are_addresses_set() |
| 3443 | ? seg2->paddr() |
| 3444 | : seg2->first_section_load_address()); |
| 3445 | |
| 3446 | if (paddr1 != paddr2) |
| 3447 | return paddr1 < paddr2; |
| 3448 | } |
| 3449 | else if (seg2->are_addresses_set()) |
| 3450 | return false; |
| 3451 | |
| 3452 | // A segment which holds large data comes after a segment which does |
| 3453 | // not hold large data. |
| 3454 | if (seg1->is_large_data_segment()) |
| 3455 | { |
| 3456 | if (!seg2->is_large_data_segment()) |
| 3457 | return false; |
| 3458 | } |
| 3459 | else if (seg2->is_large_data_segment()) |
| 3460 | return true; |
| 3461 | |
| 3462 | // Otherwise, we sort PT_LOAD segments based on the flags. Readonly |
| 3463 | // segments come before writable segments. Then writable segments |
| 3464 | // with data come before writable segments without data. Then |
| 3465 | // executable segments come before non-executable segments. Then |
| 3466 | // the unlikely case of a non-readable segment comes before the |
| 3467 | // normal case of a readable segment. If there are multiple |
| 3468 | // segments with the same type and flags, we require that the |
| 3469 | // address be set, and we sort by virtual address and then physical |
| 3470 | // address. |
| 3471 | if ((flags1 & elfcpp::PF_W) != (flags2 & elfcpp::PF_W)) |
| 3472 | return (flags1 & elfcpp::PF_W) == 0; |
| 3473 | if ((flags1 & elfcpp::PF_W) != 0 |
| 3474 | && seg1->has_any_data_sections() != seg2->has_any_data_sections()) |
| 3475 | return seg1->has_any_data_sections(); |
| 3476 | if ((flags1 & elfcpp::PF_X) != (flags2 & elfcpp::PF_X)) |
| 3477 | return (flags1 & elfcpp::PF_X) != 0; |
| 3478 | if ((flags1 & elfcpp::PF_R) != (flags2 & elfcpp::PF_R)) |
| 3479 | return (flags1 & elfcpp::PF_R) == 0; |
| 3480 | |
| 3481 | // We shouldn't get here--we shouldn't create segments which we |
| 3482 | // can't distinguish. Unless of course we are using a weird linker |
| 3483 | // script or overlapping --section-start options. We could also get |
| 3484 | // here if plugins want unique segments for subsets of sections. |
| 3485 | gold_assert(this->script_options_->saw_phdrs_clause() |
| 3486 | || parameters->options().any_section_start() |
| 3487 | || this->is_unique_segment_for_sections_specified() |
| 3488 | || parameters->options().text_unlikely_segment()); |
| 3489 | return false; |
| 3490 | } |
| 3491 | |
| 3492 | // Increase OFF so that it is congruent to ADDR modulo ABI_PAGESIZE. |
| 3493 | |
| 3494 | static off_t |
| 3495 | align_file_offset(off_t off, uint64_t addr, uint64_t abi_pagesize) |
| 3496 | { |
| 3497 | uint64_t unsigned_off = off; |
| 3498 | uint64_t aligned_off = ((unsigned_off & ~(abi_pagesize - 1)) |
| 3499 | | (addr & (abi_pagesize - 1))); |
| 3500 | if (aligned_off < unsigned_off) |
| 3501 | aligned_off += abi_pagesize; |
| 3502 | return aligned_off; |
| 3503 | } |
| 3504 | |
| 3505 | // On targets where the text segment contains only executable code, |
| 3506 | // a non-executable segment is never the text segment. |
| 3507 | |
| 3508 | static inline bool |
| 3509 | is_text_segment(const Target* target, const Output_segment* seg) |
| 3510 | { |
| 3511 | elfcpp::Elf_Xword flags = seg->flags(); |
| 3512 | if ((flags & elfcpp::PF_W) != 0) |
| 3513 | return false; |
| 3514 | if ((flags & elfcpp::PF_X) == 0) |
| 3515 | return !target->isolate_execinstr(); |
| 3516 | return true; |
| 3517 | } |
| 3518 | |
| 3519 | // Set the file offsets of all the segments, and all the sections they |
| 3520 | // contain. They have all been created. LOAD_SEG must be laid out |
| 3521 | // first. Return the offset of the data to follow. |
| 3522 | |
| 3523 | off_t |
| 3524 | Layout::set_segment_offsets(const Target* target, Output_segment* load_seg, |
| 3525 | unsigned int* pshndx) |
| 3526 | { |
| 3527 | // Sort them into the final order. We use a stable sort so that we |
| 3528 | // don't randomize the order of indistinguishable segments created |
| 3529 | // by linker scripts. |
| 3530 | std::stable_sort(this->segment_list_.begin(), this->segment_list_.end(), |
| 3531 | Layout::Compare_segments(this)); |
| 3532 | |
| 3533 | // Find the PT_LOAD segments, and set their addresses and offsets |
| 3534 | // and their section's addresses and offsets. |
| 3535 | uint64_t start_addr; |
| 3536 | if (parameters->options().user_set_Ttext()) |
| 3537 | start_addr = parameters->options().Ttext(); |
| 3538 | else if (parameters->options().output_is_position_independent()) |
| 3539 | start_addr = 0; |
| 3540 | else |
| 3541 | start_addr = target->default_text_segment_address(); |
| 3542 | |
| 3543 | uint64_t addr = start_addr; |
| 3544 | off_t off = 0; |
| 3545 | |
| 3546 | // If LOAD_SEG is NULL, then the file header and segment headers |
| 3547 | // will not be loadable. But they still need to be at offset 0 in |
| 3548 | // the file. Set their offsets now. |
| 3549 | if (load_seg == NULL) |
| 3550 | { |
| 3551 | for (Data_list::iterator p = this->special_output_list_.begin(); |
| 3552 | p != this->special_output_list_.end(); |
| 3553 | ++p) |
| 3554 | { |
| 3555 | off = align_address(off, (*p)->addralign()); |
| 3556 | (*p)->set_address_and_file_offset(0, off); |
| 3557 | off += (*p)->data_size(); |
| 3558 | } |
| 3559 | } |
| 3560 | |
| 3561 | unsigned int increase_relro = this->increase_relro_; |
| 3562 | if (this->script_options_->saw_sections_clause()) |
| 3563 | increase_relro = 0; |
| 3564 | |
| 3565 | const bool check_sections = parameters->options().check_sections(); |
| 3566 | Output_segment* last_load_segment = NULL; |
| 3567 | |
| 3568 | unsigned int shndx_begin = *pshndx; |
| 3569 | unsigned int shndx_load_seg = *pshndx; |
| 3570 | |
| 3571 | for (Segment_list::iterator p = this->segment_list_.begin(); |
| 3572 | p != this->segment_list_.end(); |
| 3573 | ++p) |
| 3574 | { |
| 3575 | if ((*p)->type() == elfcpp::PT_LOAD) |
| 3576 | { |
| 3577 | if (target->isolate_execinstr()) |
| 3578 | { |
| 3579 | // When we hit the segment that should contain the |
| 3580 | // file headers, reset the file offset so we place |
| 3581 | // it and subsequent segments appropriately. |
| 3582 | // We'll fix up the preceding segments below. |
| 3583 | if (load_seg == *p) |
| 3584 | { |
| 3585 | if (off == 0) |
| 3586 | load_seg = NULL; |
| 3587 | else |
| 3588 | { |
| 3589 | off = 0; |
| 3590 | shndx_load_seg = *pshndx; |
| 3591 | } |
| 3592 | } |
| 3593 | } |
| 3594 | else |
| 3595 | { |
| 3596 | // Verify that the file headers fall into the first segment. |
| 3597 | if (load_seg != NULL && load_seg != *p) |
| 3598 | gold_unreachable(); |
| 3599 | load_seg = NULL; |
| 3600 | } |
| 3601 | |
| 3602 | bool are_addresses_set = (*p)->are_addresses_set(); |
| 3603 | if (are_addresses_set) |
| 3604 | { |
| 3605 | // When it comes to setting file offsets, we care about |
| 3606 | // the physical address. |
| 3607 | addr = (*p)->paddr(); |
| 3608 | } |
| 3609 | else if (parameters->options().user_set_Ttext() |
| 3610 | && (parameters->options().omagic() |
| 3611 | || is_text_segment(target, *p))) |
| 3612 | { |
| 3613 | are_addresses_set = true; |
| 3614 | } |
| 3615 | else if (parameters->options().user_set_Trodata_segment() |
| 3616 | && ((*p)->flags() & (elfcpp::PF_W | elfcpp::PF_X)) == 0) |
| 3617 | { |
| 3618 | addr = parameters->options().Trodata_segment(); |
| 3619 | are_addresses_set = true; |
| 3620 | } |
| 3621 | else if (parameters->options().user_set_Tdata() |
| 3622 | && ((*p)->flags() & elfcpp::PF_W) != 0 |
| 3623 | && (!parameters->options().user_set_Tbss() |
| 3624 | || (*p)->has_any_data_sections())) |
| 3625 | { |
| 3626 | addr = parameters->options().Tdata(); |
| 3627 | are_addresses_set = true; |
| 3628 | } |
| 3629 | else if (parameters->options().user_set_Tbss() |
| 3630 | && ((*p)->flags() & elfcpp::PF_W) != 0 |
| 3631 | && !(*p)->has_any_data_sections()) |
| 3632 | { |
| 3633 | addr = parameters->options().Tbss(); |
| 3634 | are_addresses_set = true; |
| 3635 | } |
| 3636 | |
| 3637 | uint64_t orig_addr = addr; |
| 3638 | uint64_t orig_off = off; |
| 3639 | |
| 3640 | uint64_t aligned_addr = 0; |
| 3641 | uint64_t abi_pagesize = target->abi_pagesize(); |
| 3642 | uint64_t common_pagesize = target->common_pagesize(); |
| 3643 | |
| 3644 | if (!parameters->options().nmagic() |
| 3645 | && !parameters->options().omagic()) |
| 3646 | (*p)->set_minimum_p_align(abi_pagesize); |
| 3647 | |
| 3648 | if (!are_addresses_set) |
| 3649 | { |
| 3650 | // Skip the address forward one page, maintaining the same |
| 3651 | // position within the page. This lets us store both segments |
| 3652 | // overlapping on a single page in the file, but the loader will |
| 3653 | // put them on different pages in memory. We will revisit this |
| 3654 | // decision once we know the size of the segment. |
| 3655 | |
| 3656 | uint64_t max_align = (*p)->maximum_alignment(); |
| 3657 | if (max_align > abi_pagesize) |
| 3658 | addr = align_address(addr, max_align); |
| 3659 | aligned_addr = addr; |
| 3660 | |
| 3661 | if (load_seg == *p) |
| 3662 | { |
| 3663 | // This is the segment that will contain the file |
| 3664 | // headers, so its offset will have to be exactly zero. |
| 3665 | gold_assert(orig_off == 0); |
| 3666 | |
| 3667 | // If the target wants a fixed minimum distance from the |
| 3668 | // text segment to the read-only segment, move up now. |
| 3669 | uint64_t min_addr = |
| 3670 | start_addr + (parameters->options().user_set_rosegment_gap() |
| 3671 | ? parameters->options().rosegment_gap() |
| 3672 | : target->rosegment_gap()); |
| 3673 | if (addr < min_addr) |
| 3674 | addr = min_addr; |
| 3675 | |
| 3676 | // But this is not the first segment! To make its |
| 3677 | // address congruent with its offset, that address better |
| 3678 | // be aligned to the ABI-mandated page size. |
| 3679 | addr = align_address(addr, abi_pagesize); |
| 3680 | aligned_addr = addr; |
| 3681 | } |
| 3682 | else |
| 3683 | { |
| 3684 | if ((addr & (abi_pagesize - 1)) != 0) |
| 3685 | addr = addr + abi_pagesize; |
| 3686 | |
| 3687 | off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); |
| 3688 | } |
| 3689 | } |
| 3690 | |
| 3691 | if (!parameters->options().nmagic() |
| 3692 | && !parameters->options().omagic()) |
| 3693 | { |
| 3694 | // Here we are also taking care of the case when |
| 3695 | // the maximum segment alignment is larger than the page size. |
| 3696 | off = align_file_offset(off, addr, |
| 3697 | std::max(abi_pagesize, |
| 3698 | (*p)->maximum_alignment())); |
| 3699 | } |
| 3700 | else |
| 3701 | { |
| 3702 | // This is -N or -n with a section script which prevents |
| 3703 | // us from using a load segment. We need to ensure that |
| 3704 | // the file offset is aligned to the alignment of the |
| 3705 | // segment. This is because the linker script |
| 3706 | // implicitly assumed a zero offset. If we don't align |
| 3707 | // here, then the alignment of the sections in the |
| 3708 | // linker script may not match the alignment of the |
| 3709 | // sections in the set_section_addresses call below, |
| 3710 | // causing an error about dot moving backward. |
| 3711 | off = align_address(off, (*p)->maximum_alignment()); |
| 3712 | } |
| 3713 | |
| 3714 | unsigned int shndx_hold = *pshndx; |
| 3715 | bool has_relro = false; |
| 3716 | uint64_t new_addr = (*p)->set_section_addresses(target, this, |
| 3717 | false, addr, |
| 3718 | &increase_relro, |
| 3719 | &has_relro, |
| 3720 | &off, pshndx); |
| 3721 | |
| 3722 | // Now that we know the size of this segment, we may be able |
| 3723 | // to save a page in memory, at the cost of wasting some |
| 3724 | // file space, by instead aligning to the start of a new |
| 3725 | // page. Here we use the real machine page size rather than |
| 3726 | // the ABI mandated page size. If the segment has been |
| 3727 | // aligned so that the relro data ends at a page boundary, |
| 3728 | // we do not try to realign it. |
| 3729 | |
| 3730 | if (!are_addresses_set |
| 3731 | && !has_relro |
| 3732 | && aligned_addr != addr |
| 3733 | && !parameters->incremental()) |
| 3734 | { |
| 3735 | uint64_t first_off = (common_pagesize |
| 3736 | - (aligned_addr |
| 3737 | & (common_pagesize - 1))); |
| 3738 | uint64_t last_off = new_addr & (common_pagesize - 1); |
| 3739 | if (first_off > 0 |
| 3740 | && last_off > 0 |
| 3741 | && ((aligned_addr & ~ (common_pagesize - 1)) |
| 3742 | != (new_addr & ~ (common_pagesize - 1))) |
| 3743 | && first_off + last_off <= common_pagesize) |
| 3744 | { |
| 3745 | *pshndx = shndx_hold; |
| 3746 | addr = align_address(aligned_addr, common_pagesize); |
| 3747 | addr = align_address(addr, (*p)->maximum_alignment()); |
| 3748 | if ((addr & (abi_pagesize - 1)) != 0) |
| 3749 | addr = addr + abi_pagesize; |
| 3750 | off = orig_off + ((addr - orig_addr) & (abi_pagesize - 1)); |
| 3751 | off = align_file_offset(off, addr, abi_pagesize); |
| 3752 | |
| 3753 | increase_relro = this->increase_relro_; |
| 3754 | if (this->script_options_->saw_sections_clause()) |
| 3755 | increase_relro = 0; |
| 3756 | has_relro = false; |
| 3757 | |
| 3758 | new_addr = (*p)->set_section_addresses(target, this, |
| 3759 | true, addr, |
| 3760 | &increase_relro, |
| 3761 | &has_relro, |
| 3762 | &off, pshndx); |
| 3763 | } |
| 3764 | } |
| 3765 | |
| 3766 | addr = new_addr; |
| 3767 | |
| 3768 | // Implement --check-sections. We know that the segments |
| 3769 | // are sorted by LMA. |
| 3770 | if (check_sections && last_load_segment != NULL) |
| 3771 | { |
| 3772 | gold_assert(last_load_segment->paddr() <= (*p)->paddr()); |
| 3773 | if (last_load_segment->paddr() + last_load_segment->memsz() |
| 3774 | > (*p)->paddr()) |
| 3775 | { |
| 3776 | unsigned long long lb1 = last_load_segment->paddr(); |
| 3777 | unsigned long long le1 = lb1 + last_load_segment->memsz(); |
| 3778 | unsigned long long lb2 = (*p)->paddr(); |
| 3779 | unsigned long long le2 = lb2 + (*p)->memsz(); |
| 3780 | gold_error(_("load segment overlap [0x%llx -> 0x%llx] and " |
| 3781 | "[0x%llx -> 0x%llx]"), |
| 3782 | lb1, le1, lb2, le2); |
| 3783 | } |
| 3784 | } |
| 3785 | last_load_segment = *p; |
| 3786 | } |
| 3787 | } |
| 3788 | |
| 3789 | if (load_seg != NULL && target->isolate_execinstr()) |
| 3790 | { |
| 3791 | // Process the early segments again, setting their file offsets |
| 3792 | // so they land after the segments starting at LOAD_SEG. |
| 3793 | off = align_file_offset(off, 0, target->abi_pagesize()); |
| 3794 | |
| 3795 | this->reset_relax_output(); |
| 3796 | |
| 3797 | for (Segment_list::iterator p = this->segment_list_.begin(); |
| 3798 | *p != load_seg; |
| 3799 | ++p) |
| 3800 | { |
| 3801 | if ((*p)->type() == elfcpp::PT_LOAD) |
| 3802 | { |
| 3803 | // We repeat the whole job of assigning addresses and |
| 3804 | // offsets, but we really only want to change the offsets and |
| 3805 | // must ensure that the addresses all come out the same as |
| 3806 | // they did the first time through. |
| 3807 | bool has_relro = false; |
| 3808 | const uint64_t old_addr = (*p)->vaddr(); |
| 3809 | const uint64_t old_end = old_addr + (*p)->memsz(); |
| 3810 | uint64_t new_addr = (*p)->set_section_addresses(target, this, |
| 3811 | true, old_addr, |
| 3812 | &increase_relro, |
| 3813 | &has_relro, |
| 3814 | &off, |
| 3815 | &shndx_begin); |
| 3816 | gold_assert(new_addr == old_end); |
| 3817 | } |
| 3818 | } |
| 3819 | |
| 3820 | gold_assert(shndx_begin == shndx_load_seg); |
| 3821 | } |
| 3822 | |
| 3823 | // Handle the non-PT_LOAD segments, setting their offsets from their |
| 3824 | // section's offsets. |
| 3825 | for (Segment_list::iterator p = this->segment_list_.begin(); |
| 3826 | p != this->segment_list_.end(); |
| 3827 | ++p) |
| 3828 | { |
| 3829 | // PT_GNU_STACK was set up correctly when it was created. |
| 3830 | if ((*p)->type() != elfcpp::PT_LOAD |
| 3831 | && (*p)->type() != elfcpp::PT_GNU_STACK) |
| 3832 | (*p)->set_offset((*p)->type() == elfcpp::PT_GNU_RELRO |
| 3833 | ? increase_relro |
| 3834 | : 0); |
| 3835 | } |
| 3836 | |
| 3837 | // Set the TLS offsets for each section in the PT_TLS segment. |
| 3838 | if (this->tls_segment_ != NULL) |
| 3839 | this->tls_segment_->set_tls_offsets(); |
| 3840 | |
| 3841 | return off; |
| 3842 | } |
| 3843 | |
| 3844 | // Set the offsets of all the allocated sections when doing a |
| 3845 | // relocatable link. This does the same jobs as set_segment_offsets, |
| 3846 | // only for a relocatable link. |
| 3847 | |
| 3848 | off_t |
| 3849 | Layout::set_relocatable_section_offsets(Output_data* file_header, |
| 3850 | unsigned int* pshndx) |
| 3851 | { |
| 3852 | off_t off = 0; |
| 3853 | |
| 3854 | file_header->set_address_and_file_offset(0, 0); |
| 3855 | off += file_header->data_size(); |
| 3856 | |
| 3857 | for (Section_list::iterator p = this->section_list_.begin(); |
| 3858 | p != this->section_list_.end(); |
| 3859 | ++p) |
| 3860 | { |
| 3861 | // We skip unallocated sections here, except that group sections |
| 3862 | // have to come first. |
| 3863 | if (((*p)->flags() & elfcpp::SHF_ALLOC) == 0 |
| 3864 | && (*p)->type() != elfcpp::SHT_GROUP) |
| 3865 | continue; |
| 3866 | |
| 3867 | off = align_address(off, (*p)->addralign()); |
| 3868 | |
| 3869 | // The linker script might have set the address. |
| 3870 | if (!(*p)->is_address_valid()) |
| 3871 | (*p)->set_address(0); |
| 3872 | (*p)->set_file_offset(off); |
| 3873 | (*p)->finalize_data_size(); |
| 3874 | if ((*p)->type() != elfcpp::SHT_NOBITS) |
| 3875 | off += (*p)->data_size(); |
| 3876 | |
| 3877 | (*p)->set_out_shndx(*pshndx); |
| 3878 | ++*pshndx; |
| 3879 | } |
| 3880 | |
| 3881 | return off; |
| 3882 | } |
| 3883 | |
| 3884 | // Set the file offset of all the sections not associated with a |
| 3885 | // segment. |
| 3886 | |
| 3887 | off_t |
| 3888 | Layout::set_section_offsets(off_t off, Layout::Section_offset_pass pass) |
| 3889 | { |
| 3890 | off_t startoff = off; |
| 3891 | off_t maxoff = off; |
| 3892 | |
| 3893 | for (Section_list::iterator p = this->unattached_section_list_.begin(); |
| 3894 | p != this->unattached_section_list_.end(); |
| 3895 | ++p) |
| 3896 | { |
| 3897 | // The symtab section is handled in create_symtab_sections. |
| 3898 | if (*p == this->symtab_section_) |
| 3899 | continue; |
| 3900 | |
| 3901 | // If we've already set the data size, don't set it again. |
| 3902 | if ((*p)->is_offset_valid() && (*p)->is_data_size_valid()) |
| 3903 | continue; |
| 3904 | |
| 3905 | if (pass == BEFORE_INPUT_SECTIONS_PASS |
| 3906 | && (*p)->requires_postprocessing()) |
| 3907 | { |
| 3908 | (*p)->create_postprocessing_buffer(); |
| 3909 | this->any_postprocessing_sections_ = true; |
| 3910 | } |
| 3911 | |
| 3912 | if (pass == BEFORE_INPUT_SECTIONS_PASS |
| 3913 | && (*p)->after_input_sections()) |
| 3914 | continue; |
| 3915 | else if (pass == POSTPROCESSING_SECTIONS_PASS |
| 3916 | && (!(*p)->after_input_sections() |
| 3917 | || (*p)->type() == elfcpp::SHT_STRTAB)) |
| 3918 | continue; |
| 3919 | else if (pass == STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS |
| 3920 | && (!(*p)->after_input_sections() |
| 3921 | || (*p)->type() != elfcpp::SHT_STRTAB)) |
| 3922 | continue; |
| 3923 | |
| 3924 | if (!parameters->incremental_update()) |
| 3925 | { |
| 3926 | off = align_address(off, (*p)->addralign()); |
| 3927 | (*p)->set_file_offset(off); |
| 3928 | (*p)->finalize_data_size(); |
| 3929 | } |
| 3930 | else |
| 3931 | { |
| 3932 | // Incremental update: allocate file space from free list. |
| 3933 | (*p)->pre_finalize_data_size(); |
| 3934 | off_t current_size = (*p)->current_data_size(); |
| 3935 | off = this->allocate(current_size, (*p)->addralign(), startoff); |
| 3936 | if (off == -1) |
| 3937 | { |
| 3938 | if (is_debugging_enabled(DEBUG_INCREMENTAL)) |
| 3939 | this->free_list_.dump(); |
| 3940 | gold_assert((*p)->output_section() != NULL); |
| 3941 | gold_fallback(_("out of patch space for section %s; " |
| 3942 | "relink with --incremental-full"), |
| 3943 | (*p)->output_section()->name()); |
| 3944 | } |
| 3945 | (*p)->set_file_offset(off); |
| 3946 | (*p)->finalize_data_size(); |
| 3947 | if ((*p)->data_size() > current_size) |
| 3948 | { |
| 3949 | gold_assert((*p)->output_section() != NULL); |
| 3950 | gold_fallback(_("%s: section changed size; " |
| 3951 | "relink with --incremental-full"), |
| 3952 | (*p)->output_section()->name()); |
| 3953 | } |
| 3954 | gold_debug(DEBUG_INCREMENTAL, |
| 3955 | "set_section_offsets: %08lx %08lx %s", |
| 3956 | static_cast<long>(off), |
| 3957 | static_cast<long>((*p)->data_size()), |
| 3958 | ((*p)->output_section() != NULL |
| 3959 | ? (*p)->output_section()->name() : "(special)")); |
| 3960 | } |
| 3961 | |
| 3962 | off += (*p)->data_size(); |
| 3963 | if (off > maxoff) |
| 3964 | maxoff = off; |
| 3965 | |
| 3966 | // At this point the name must be set. |
| 3967 | if (pass != STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS) |
| 3968 | this->namepool_.add((*p)->name(), false, NULL); |
| 3969 | } |
| 3970 | return maxoff; |
| 3971 | } |
| 3972 | |
| 3973 | // Set the section indexes of all the sections not associated with a |
| 3974 | // segment. |
| 3975 | |
| 3976 | unsigned int |
| 3977 | Layout::set_section_indexes(unsigned int shndx) |
| 3978 | { |
| 3979 | for (Section_list::iterator p = this->unattached_section_list_.begin(); |
| 3980 | p != this->unattached_section_list_.end(); |
| 3981 | ++p) |
| 3982 | { |
| 3983 | if (!(*p)->has_out_shndx()) |
| 3984 | { |
| 3985 | (*p)->set_out_shndx(shndx); |
| 3986 | ++shndx; |
| 3987 | } |
| 3988 | } |
| 3989 | return shndx; |
| 3990 | } |
| 3991 | |
| 3992 | // Set the section addresses according to the linker script. This is |
| 3993 | // only called when we see a SECTIONS clause. This returns the |
| 3994 | // program segment which should hold the file header and segment |
| 3995 | // headers, if any. It will return NULL if they should not be in a |
| 3996 | // segment. |
| 3997 | |
| 3998 | Output_segment* |
| 3999 | Layout::set_section_addresses_from_script(Symbol_table* symtab) |
| 4000 | { |
| 4001 | Script_sections* ss = this->script_options_->script_sections(); |
| 4002 | gold_assert(ss->saw_sections_clause()); |
| 4003 | return this->script_options_->set_section_addresses(symtab, this); |
| 4004 | } |
| 4005 | |
| 4006 | // Place the orphan sections in the linker script. |
| 4007 | |
| 4008 | void |
| 4009 | Layout::place_orphan_sections_in_script() |
| 4010 | { |
| 4011 | Script_sections* ss = this->script_options_->script_sections(); |
| 4012 | gold_assert(ss->saw_sections_clause()); |
| 4013 | |
| 4014 | // Place each orphaned output section in the script. |
| 4015 | for (Section_list::iterator p = this->section_list_.begin(); |
| 4016 | p != this->section_list_.end(); |
| 4017 | ++p) |
| 4018 | { |
| 4019 | if (!(*p)->found_in_sections_clause()) |
| 4020 | ss->place_orphan(*p); |
| 4021 | } |
| 4022 | } |
| 4023 | |
| 4024 | // Count the local symbols in the regular symbol table and the dynamic |
| 4025 | // symbol table, and build the respective string pools. |
| 4026 | |
| 4027 | void |
| 4028 | Layout::count_local_symbols(const Task* task, |
| 4029 | const Input_objects* input_objects) |
| 4030 | { |
| 4031 | // First, figure out an upper bound on the number of symbols we'll |
| 4032 | // be inserting into each pool. This helps us create the pools with |
| 4033 | // the right size, to avoid unnecessary hashtable resizing. |
| 4034 | unsigned int symbol_count = 0; |
| 4035 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 4036 | p != input_objects->relobj_end(); |
| 4037 | ++p) |
| 4038 | symbol_count += (*p)->local_symbol_count(); |
| 4039 | |
| 4040 | // Go from "upper bound" to "estimate." We overcount for two |
| 4041 | // reasons: we double-count symbols that occur in more than one |
| 4042 | // object file, and we count symbols that are dropped from the |
| 4043 | // output. Add it all together and assume we overcount by 100%. |
| 4044 | symbol_count /= 2; |
| 4045 | |
| 4046 | // We assume all symbols will go into both the sympool and dynpool. |
| 4047 | this->sympool_.reserve(symbol_count); |
| 4048 | this->dynpool_.reserve(symbol_count); |
| 4049 | |
| 4050 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 4051 | p != input_objects->relobj_end(); |
| 4052 | ++p) |
| 4053 | { |
| 4054 | Task_lock_obj<Object> tlo(task, *p); |
| 4055 | (*p)->count_local_symbols(&this->sympool_, &this->dynpool_); |
| 4056 | } |
| 4057 | } |
| 4058 | |
| 4059 | // Create the symbol table sections. Here we also set the final |
| 4060 | // values of the symbols. At this point all the loadable sections are |
| 4061 | // fully laid out. SHNUM is the number of sections so far. |
| 4062 | |
| 4063 | void |
| 4064 | Layout::create_symtab_sections(const Input_objects* input_objects, |
| 4065 | Symbol_table* symtab, |
| 4066 | unsigned int shnum, |
| 4067 | off_t* poff, |
| 4068 | unsigned int local_dynamic_count) |
| 4069 | { |
| 4070 | int symsize; |
| 4071 | unsigned int align; |
| 4072 | if (parameters->target().get_size() == 32) |
| 4073 | { |
| 4074 | symsize = elfcpp::Elf_sizes<32>::sym_size; |
| 4075 | align = 4; |
| 4076 | } |
| 4077 | else if (parameters->target().get_size() == 64) |
| 4078 | { |
| 4079 | symsize = elfcpp::Elf_sizes<64>::sym_size; |
| 4080 | align = 8; |
| 4081 | } |
| 4082 | else |
| 4083 | gold_unreachable(); |
| 4084 | |
| 4085 | // Compute file offsets relative to the start of the symtab section. |
| 4086 | off_t off = 0; |
| 4087 | |
| 4088 | // Save space for the dummy symbol at the start of the section. We |
| 4089 | // never bother to write this out--it will just be left as zero. |
| 4090 | off += symsize; |
| 4091 | unsigned int local_symbol_index = 1; |
| 4092 | |
| 4093 | // Add STT_SECTION symbols for each Output section which needs one. |
| 4094 | for (Section_list::iterator p = this->section_list_.begin(); |
| 4095 | p != this->section_list_.end(); |
| 4096 | ++p) |
| 4097 | { |
| 4098 | if (!(*p)->needs_symtab_index()) |
| 4099 | (*p)->set_symtab_index(-1U); |
| 4100 | else |
| 4101 | { |
| 4102 | (*p)->set_symtab_index(local_symbol_index); |
| 4103 | ++local_symbol_index; |
| 4104 | off += symsize; |
| 4105 | } |
| 4106 | } |
| 4107 | |
| 4108 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 4109 | p != input_objects->relobj_end(); |
| 4110 | ++p) |
| 4111 | { |
| 4112 | unsigned int index = (*p)->finalize_local_symbols(local_symbol_index, |
| 4113 | off, symtab); |
| 4114 | off += (index - local_symbol_index) * symsize; |
| 4115 | local_symbol_index = index; |
| 4116 | } |
| 4117 | |
| 4118 | unsigned int local_symcount = local_symbol_index; |
| 4119 | gold_assert(static_cast<off_t>(local_symcount * symsize) == off); |
| 4120 | |
| 4121 | off_t dynoff; |
| 4122 | size_t dyncount; |
| 4123 | if (this->dynsym_section_ == NULL) |
| 4124 | { |
| 4125 | dynoff = 0; |
| 4126 | dyncount = 0; |
| 4127 | } |
| 4128 | else |
| 4129 | { |
| 4130 | off_t locsize = local_dynamic_count * this->dynsym_section_->entsize(); |
| 4131 | dynoff = this->dynsym_section_->offset() + locsize; |
| 4132 | dyncount = (this->dynsym_section_->data_size() - locsize) / symsize; |
| 4133 | gold_assert(static_cast<off_t>(dyncount * symsize) |
| 4134 | == this->dynsym_section_->data_size() - locsize); |
| 4135 | } |
| 4136 | |
| 4137 | off_t global_off = off; |
| 4138 | off = symtab->finalize(off, dynoff, local_dynamic_count, dyncount, |
| 4139 | &this->sympool_, &local_symcount); |
| 4140 | |
| 4141 | if (!parameters->options().strip_all()) |
| 4142 | { |
| 4143 | this->sympool_.set_string_offsets(); |
| 4144 | |
| 4145 | const char* symtab_name = this->namepool_.add(".symtab", false, NULL); |
| 4146 | Output_section* osymtab = this->make_output_section(symtab_name, |
| 4147 | elfcpp::SHT_SYMTAB, |
| 4148 | 0, ORDER_INVALID, |
| 4149 | false); |
| 4150 | this->symtab_section_ = osymtab; |
| 4151 | |
| 4152 | Output_section_data* pos = new Output_data_fixed_space(off, align, |
| 4153 | "** symtab"); |
| 4154 | osymtab->add_output_section_data(pos); |
| 4155 | |
| 4156 | // We generate a .symtab_shndx section if we have more than |
| 4157 | // SHN_LORESERVE sections. Technically it is possible that we |
| 4158 | // don't need one, because it is possible that there are no |
| 4159 | // symbols in any of sections with indexes larger than |
| 4160 | // SHN_LORESERVE. That is probably unusual, though, and it is |
| 4161 | // easier to always create one than to compute section indexes |
| 4162 | // twice (once here, once when writing out the symbols). |
| 4163 | if (shnum >= elfcpp::SHN_LORESERVE) |
| 4164 | { |
| 4165 | const char* symtab_xindex_name = this->namepool_.add(".symtab_shndx", |
| 4166 | false, NULL); |
| 4167 | Output_section* osymtab_xindex = |
| 4168 | this->make_output_section(symtab_xindex_name, |
| 4169 | elfcpp::SHT_SYMTAB_SHNDX, 0, |
| 4170 | ORDER_INVALID, false); |
| 4171 | |
| 4172 | size_t symcount = off / symsize; |
| 4173 | this->symtab_xindex_ = new Output_symtab_xindex(symcount); |
| 4174 | |
| 4175 | osymtab_xindex->add_output_section_data(this->symtab_xindex_); |
| 4176 | |
| 4177 | osymtab_xindex->set_link_section(osymtab); |
| 4178 | osymtab_xindex->set_addralign(4); |
| 4179 | osymtab_xindex->set_entsize(4); |
| 4180 | |
| 4181 | osymtab_xindex->set_after_input_sections(); |
| 4182 | |
| 4183 | // This tells the driver code to wait until the symbol table |
| 4184 | // has written out before writing out the postprocessing |
| 4185 | // sections, including the .symtab_shndx section. |
| 4186 | this->any_postprocessing_sections_ = true; |
| 4187 | } |
| 4188 | |
| 4189 | const char* strtab_name = this->namepool_.add(".strtab", false, NULL); |
| 4190 | Output_section* ostrtab = this->make_output_section(strtab_name, |
| 4191 | elfcpp::SHT_STRTAB, |
| 4192 | 0, ORDER_INVALID, |
| 4193 | false); |
| 4194 | |
| 4195 | Output_section_data* pstr = new Output_data_strtab(&this->sympool_); |
| 4196 | ostrtab->add_output_section_data(pstr); |
| 4197 | |
| 4198 | off_t symtab_off; |
| 4199 | if (!parameters->incremental_update()) |
| 4200 | symtab_off = align_address(*poff, align); |
| 4201 | else |
| 4202 | { |
| 4203 | symtab_off = this->allocate(off, align, *poff); |
| 4204 | if (off == -1) |
| 4205 | gold_fallback(_("out of patch space for symbol table; " |
| 4206 | "relink with --incremental-full")); |
| 4207 | gold_debug(DEBUG_INCREMENTAL, |
| 4208 | "create_symtab_sections: %08lx %08lx .symtab", |
| 4209 | static_cast<long>(symtab_off), |
| 4210 | static_cast<long>(off)); |
| 4211 | } |
| 4212 | |
| 4213 | symtab->set_file_offset(symtab_off + global_off); |
| 4214 | osymtab->set_file_offset(symtab_off); |
| 4215 | osymtab->finalize_data_size(); |
| 4216 | osymtab->set_link_section(ostrtab); |
| 4217 | osymtab->set_info(local_symcount); |
| 4218 | osymtab->set_entsize(symsize); |
| 4219 | |
| 4220 | if (symtab_off + off > *poff) |
| 4221 | *poff = symtab_off + off; |
| 4222 | } |
| 4223 | } |
| 4224 | |
| 4225 | // Create the .shstrtab section, which holds the names of the |
| 4226 | // sections. At the time this is called, we have created all the |
| 4227 | // output sections except .shstrtab itself. |
| 4228 | |
| 4229 | Output_section* |
| 4230 | Layout::create_shstrtab() |
| 4231 | { |
| 4232 | // FIXME: We don't need to create a .shstrtab section if we are |
| 4233 | // stripping everything. |
| 4234 | |
| 4235 | const char* name = this->namepool_.add(".shstrtab", false, NULL); |
| 4236 | |
| 4237 | Output_section* os = this->make_output_section(name, elfcpp::SHT_STRTAB, 0, |
| 4238 | ORDER_INVALID, false); |
| 4239 | |
| 4240 | if (strcmp(parameters->options().compress_debug_sections(), "none") != 0) |
| 4241 | { |
| 4242 | // We can't write out this section until we've set all the |
| 4243 | // section names, and we don't set the names of compressed |
| 4244 | // output sections until relocations are complete. FIXME: With |
| 4245 | // the current names we use, this is unnecessary. |
| 4246 | os->set_after_input_sections(); |
| 4247 | } |
| 4248 | |
| 4249 | Output_section_data* posd = new Output_data_strtab(&this->namepool_); |
| 4250 | os->add_output_section_data(posd); |
| 4251 | |
| 4252 | return os; |
| 4253 | } |
| 4254 | |
| 4255 | // Create the section headers. SIZE is 32 or 64. OFF is the file |
| 4256 | // offset. |
| 4257 | |
| 4258 | void |
| 4259 | Layout::create_shdrs(const Output_section* shstrtab_section, off_t* poff) |
| 4260 | { |
| 4261 | Output_section_headers* oshdrs; |
| 4262 | oshdrs = new Output_section_headers(this, |
| 4263 | &this->segment_list_, |
| 4264 | &this->section_list_, |
| 4265 | &this->unattached_section_list_, |
| 4266 | &this->namepool_, |
| 4267 | shstrtab_section); |
| 4268 | off_t off; |
| 4269 | if (!parameters->incremental_update()) |
| 4270 | off = align_address(*poff, oshdrs->addralign()); |
| 4271 | else |
| 4272 | { |
| 4273 | oshdrs->pre_finalize_data_size(); |
| 4274 | off = this->allocate(oshdrs->data_size(), oshdrs->addralign(), *poff); |
| 4275 | if (off == -1) |
| 4276 | gold_fallback(_("out of patch space for section header table; " |
| 4277 | "relink with --incremental-full")); |
| 4278 | gold_debug(DEBUG_INCREMENTAL, |
| 4279 | "create_shdrs: %08lx %08lx (section header table)", |
| 4280 | static_cast<long>(off), |
| 4281 | static_cast<long>(off + oshdrs->data_size())); |
| 4282 | } |
| 4283 | oshdrs->set_address_and_file_offset(0, off); |
| 4284 | off += oshdrs->data_size(); |
| 4285 | if (off > *poff) |
| 4286 | *poff = off; |
| 4287 | this->section_headers_ = oshdrs; |
| 4288 | } |
| 4289 | |
| 4290 | // Count the allocated sections. |
| 4291 | |
| 4292 | size_t |
| 4293 | Layout::allocated_output_section_count() const |
| 4294 | { |
| 4295 | size_t section_count = 0; |
| 4296 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 4297 | p != this->segment_list_.end(); |
| 4298 | ++p) |
| 4299 | section_count += (*p)->output_section_count(); |
| 4300 | return section_count; |
| 4301 | } |
| 4302 | |
| 4303 | // Create the dynamic symbol table. |
| 4304 | // *PLOCAL_DYNAMIC_COUNT will be set to the number of local symbols |
| 4305 | // from input objects, and *PFORCED_LOCAL_DYNAMIC_COUNT will be set |
| 4306 | // to the number of global symbols that have been forced local. |
| 4307 | // We need to remember the former because the forced-local symbols are |
| 4308 | // written along with the global symbols in Symtab::write_globals(). |
| 4309 | |
| 4310 | void |
| 4311 | Layout::create_dynamic_symtab(const Input_objects* input_objects, |
| 4312 | Symbol_table* symtab, |
| 4313 | Output_section** pdynstr, |
| 4314 | unsigned int* plocal_dynamic_count, |
| 4315 | unsigned int* pforced_local_dynamic_count, |
| 4316 | std::vector<Symbol*>* pdynamic_symbols, |
| 4317 | Versions* pversions) |
| 4318 | { |
| 4319 | // Count all the symbols in the dynamic symbol table, and set the |
| 4320 | // dynamic symbol indexes. |
| 4321 | |
| 4322 | // Skip symbol 0, which is always all zeroes. |
| 4323 | unsigned int index = 1; |
| 4324 | |
| 4325 | // Add STT_SECTION symbols for each Output section which needs one. |
| 4326 | for (Section_list::iterator p = this->section_list_.begin(); |
| 4327 | p != this->section_list_.end(); |
| 4328 | ++p) |
| 4329 | { |
| 4330 | if (!(*p)->needs_dynsym_index()) |
| 4331 | (*p)->set_dynsym_index(-1U); |
| 4332 | else |
| 4333 | { |
| 4334 | (*p)->set_dynsym_index(index); |
| 4335 | ++index; |
| 4336 | } |
| 4337 | } |
| 4338 | |
| 4339 | // Count the local symbols that need to go in the dynamic symbol table, |
| 4340 | // and set the dynamic symbol indexes. |
| 4341 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 4342 | p != input_objects->relobj_end(); |
| 4343 | ++p) |
| 4344 | { |
| 4345 | unsigned int new_index = (*p)->set_local_dynsym_indexes(index); |
| 4346 | index = new_index; |
| 4347 | } |
| 4348 | |
| 4349 | unsigned int local_symcount = index; |
| 4350 | unsigned int forced_local_count = 0; |
| 4351 | |
| 4352 | index = symtab->set_dynsym_indexes(index, &forced_local_count, |
| 4353 | pdynamic_symbols, &this->dynpool_, |
| 4354 | pversions); |
| 4355 | |
| 4356 | *plocal_dynamic_count = local_symcount; |
| 4357 | *pforced_local_dynamic_count = forced_local_count; |
| 4358 | |
| 4359 | int symsize; |
| 4360 | unsigned int align; |
| 4361 | const int size = parameters->target().get_size(); |
| 4362 | if (size == 32) |
| 4363 | { |
| 4364 | symsize = elfcpp::Elf_sizes<32>::sym_size; |
| 4365 | align = 4; |
| 4366 | } |
| 4367 | else if (size == 64) |
| 4368 | { |
| 4369 | symsize = elfcpp::Elf_sizes<64>::sym_size; |
| 4370 | align = 8; |
| 4371 | } |
| 4372 | else |
| 4373 | gold_unreachable(); |
| 4374 | |
| 4375 | // Create the dynamic symbol table section. |
| 4376 | |
| 4377 | Output_section* dynsym = this->choose_output_section(NULL, ".dynsym", |
| 4378 | elfcpp::SHT_DYNSYM, |
| 4379 | elfcpp::SHF_ALLOC, |
| 4380 | false, |
| 4381 | ORDER_DYNAMIC_LINKER, |
| 4382 | false, false, false); |
| 4383 | |
| 4384 | // Check for NULL as a linker script may discard .dynsym. |
| 4385 | if (dynsym != NULL) |
| 4386 | { |
| 4387 | Output_section_data* odata = new Output_data_fixed_space(index * symsize, |
| 4388 | align, |
| 4389 | "** dynsym"); |
| 4390 | dynsym->add_output_section_data(odata); |
| 4391 | |
| 4392 | dynsym->set_info(local_symcount + forced_local_count); |
| 4393 | dynsym->set_entsize(symsize); |
| 4394 | dynsym->set_addralign(align); |
| 4395 | |
| 4396 | this->dynsym_section_ = dynsym; |
| 4397 | } |
| 4398 | |
| 4399 | Output_data_dynamic* const odyn = this->dynamic_data_; |
| 4400 | if (odyn != NULL) |
| 4401 | { |
| 4402 | odyn->add_section_address(elfcpp::DT_SYMTAB, dynsym); |
| 4403 | odyn->add_constant(elfcpp::DT_SYMENT, symsize); |
| 4404 | } |
| 4405 | |
| 4406 | // If there are more than SHN_LORESERVE allocated sections, we |
| 4407 | // create a .dynsym_shndx section. It is possible that we don't |
| 4408 | // need one, because it is possible that there are no dynamic |
| 4409 | // symbols in any of the sections with indexes larger than |
| 4410 | // SHN_LORESERVE. This is probably unusual, though, and at this |
| 4411 | // time we don't know the actual section indexes so it is |
| 4412 | // inconvenient to check. |
| 4413 | if (this->allocated_output_section_count() >= elfcpp::SHN_LORESERVE) |
| 4414 | { |
| 4415 | Output_section* dynsym_xindex = |
| 4416 | this->choose_output_section(NULL, ".dynsym_shndx", |
| 4417 | elfcpp::SHT_SYMTAB_SHNDX, |
| 4418 | elfcpp::SHF_ALLOC, |
| 4419 | false, ORDER_DYNAMIC_LINKER, false, false, |
| 4420 | false); |
| 4421 | |
| 4422 | if (dynsym_xindex != NULL) |
| 4423 | { |
| 4424 | this->dynsym_xindex_ = new Output_symtab_xindex(index); |
| 4425 | |
| 4426 | dynsym_xindex->add_output_section_data(this->dynsym_xindex_); |
| 4427 | |
| 4428 | dynsym_xindex->set_link_section(dynsym); |
| 4429 | dynsym_xindex->set_addralign(4); |
| 4430 | dynsym_xindex->set_entsize(4); |
| 4431 | |
| 4432 | dynsym_xindex->set_after_input_sections(); |
| 4433 | |
| 4434 | // This tells the driver code to wait until the symbol table |
| 4435 | // has written out before writing out the postprocessing |
| 4436 | // sections, including the .dynsym_shndx section. |
| 4437 | this->any_postprocessing_sections_ = true; |
| 4438 | } |
| 4439 | } |
| 4440 | |
| 4441 | // Create the dynamic string table section. |
| 4442 | |
| 4443 | Output_section* dynstr = this->choose_output_section(NULL, ".dynstr", |
| 4444 | elfcpp::SHT_STRTAB, |
| 4445 | elfcpp::SHF_ALLOC, |
| 4446 | false, |
| 4447 | ORDER_DYNAMIC_LINKER, |
| 4448 | false, false, false); |
| 4449 | *pdynstr = dynstr; |
| 4450 | if (dynstr != NULL) |
| 4451 | { |
| 4452 | Output_section_data* strdata = new Output_data_strtab(&this->dynpool_); |
| 4453 | dynstr->add_output_section_data(strdata); |
| 4454 | |
| 4455 | if (dynsym != NULL) |
| 4456 | dynsym->set_link_section(dynstr); |
| 4457 | if (this->dynamic_section_ != NULL) |
| 4458 | this->dynamic_section_->set_link_section(dynstr); |
| 4459 | |
| 4460 | if (odyn != NULL) |
| 4461 | { |
| 4462 | odyn->add_section_address(elfcpp::DT_STRTAB, dynstr); |
| 4463 | odyn->add_section_size(elfcpp::DT_STRSZ, dynstr); |
| 4464 | } |
| 4465 | } |
| 4466 | |
| 4467 | // Create the hash tables. The Gnu-style hash table must be |
| 4468 | // built first, because it changes the order of the symbols |
| 4469 | // in the dynamic symbol table. |
| 4470 | |
| 4471 | if (strcmp(parameters->options().hash_style(), "gnu") == 0 |
| 4472 | || strcmp(parameters->options().hash_style(), "both") == 0) |
| 4473 | { |
| 4474 | unsigned char* phash; |
| 4475 | unsigned int hashlen; |
| 4476 | Dynobj::create_gnu_hash_table(*pdynamic_symbols, |
| 4477 | local_symcount + forced_local_count, |
| 4478 | &phash, &hashlen); |
| 4479 | |
| 4480 | Output_section* hashsec = |
| 4481 | this->choose_output_section(NULL, ".gnu.hash", elfcpp::SHT_GNU_HASH, |
| 4482 | elfcpp::SHF_ALLOC, false, |
| 4483 | ORDER_DYNAMIC_LINKER, false, false, |
| 4484 | false); |
| 4485 | |
| 4486 | Output_section_data* hashdata = new Output_data_const_buffer(phash, |
| 4487 | hashlen, |
| 4488 | align, |
| 4489 | "** hash"); |
| 4490 | if (hashsec != NULL && hashdata != NULL) |
| 4491 | hashsec->add_output_section_data(hashdata); |
| 4492 | |
| 4493 | if (hashsec != NULL) |
| 4494 | { |
| 4495 | if (dynsym != NULL) |
| 4496 | hashsec->set_link_section(dynsym); |
| 4497 | |
| 4498 | // For a 64-bit target, the entries in .gnu.hash do not have |
| 4499 | // a uniform size, so we only set the entry size for a |
| 4500 | // 32-bit target. |
| 4501 | if (parameters->target().get_size() == 32) |
| 4502 | hashsec->set_entsize(4); |
| 4503 | |
| 4504 | if (odyn != NULL) |
| 4505 | odyn->add_section_address(elfcpp::DT_GNU_HASH, hashsec); |
| 4506 | } |
| 4507 | } |
| 4508 | |
| 4509 | if (strcmp(parameters->options().hash_style(), "sysv") == 0 |
| 4510 | || strcmp(parameters->options().hash_style(), "both") == 0) |
| 4511 | { |
| 4512 | unsigned char* phash; |
| 4513 | unsigned int hashlen; |
| 4514 | Dynobj::create_elf_hash_table(*pdynamic_symbols, |
| 4515 | local_symcount + forced_local_count, |
| 4516 | &phash, &hashlen); |
| 4517 | |
| 4518 | Output_section* hashsec = |
| 4519 | this->choose_output_section(NULL, ".hash", elfcpp::SHT_HASH, |
| 4520 | elfcpp::SHF_ALLOC, false, |
| 4521 | ORDER_DYNAMIC_LINKER, false, false, |
| 4522 | false); |
| 4523 | |
| 4524 | Output_section_data* hashdata = new Output_data_const_buffer(phash, |
| 4525 | hashlen, |
| 4526 | align, |
| 4527 | "** hash"); |
| 4528 | if (hashsec != NULL && hashdata != NULL) |
| 4529 | hashsec->add_output_section_data(hashdata); |
| 4530 | |
| 4531 | if (hashsec != NULL) |
| 4532 | { |
| 4533 | if (dynsym != NULL) |
| 4534 | hashsec->set_link_section(dynsym); |
| 4535 | hashsec->set_entsize(parameters->target().hash_entry_size() / 8); |
| 4536 | } |
| 4537 | |
| 4538 | if (odyn != NULL) |
| 4539 | odyn->add_section_address(elfcpp::DT_HASH, hashsec); |
| 4540 | } |
| 4541 | } |
| 4542 | |
| 4543 | // Assign offsets to each local portion of the dynamic symbol table. |
| 4544 | |
| 4545 | void |
| 4546 | Layout::assign_local_dynsym_offsets(const Input_objects* input_objects) |
| 4547 | { |
| 4548 | Output_section* dynsym = this->dynsym_section_; |
| 4549 | if (dynsym == NULL) |
| 4550 | return; |
| 4551 | |
| 4552 | off_t off = dynsym->offset(); |
| 4553 | |
| 4554 | // Skip the dummy symbol at the start of the section. |
| 4555 | off += dynsym->entsize(); |
| 4556 | |
| 4557 | for (Input_objects::Relobj_iterator p = input_objects->relobj_begin(); |
| 4558 | p != input_objects->relobj_end(); |
| 4559 | ++p) |
| 4560 | { |
| 4561 | unsigned int count = (*p)->set_local_dynsym_offset(off); |
| 4562 | off += count * dynsym->entsize(); |
| 4563 | } |
| 4564 | } |
| 4565 | |
| 4566 | // Create the version sections. |
| 4567 | |
| 4568 | void |
| 4569 | Layout::create_version_sections(const Versions* versions, |
| 4570 | const Symbol_table* symtab, |
| 4571 | unsigned int local_symcount, |
| 4572 | const std::vector<Symbol*>& dynamic_symbols, |
| 4573 | const Output_section* dynstr) |
| 4574 | { |
| 4575 | if (!versions->any_defs() && !versions->any_needs()) |
| 4576 | return; |
| 4577 | |
| 4578 | switch (parameters->size_and_endianness()) |
| 4579 | { |
| 4580 | #ifdef HAVE_TARGET_32_LITTLE |
| 4581 | case Parameters::TARGET_32_LITTLE: |
| 4582 | this->sized_create_version_sections<32, false>(versions, symtab, |
| 4583 | local_symcount, |
| 4584 | dynamic_symbols, dynstr); |
| 4585 | break; |
| 4586 | #endif |
| 4587 | #ifdef HAVE_TARGET_32_BIG |
| 4588 | case Parameters::TARGET_32_BIG: |
| 4589 | this->sized_create_version_sections<32, true>(versions, symtab, |
| 4590 | local_symcount, |
| 4591 | dynamic_symbols, dynstr); |
| 4592 | break; |
| 4593 | #endif |
| 4594 | #ifdef HAVE_TARGET_64_LITTLE |
| 4595 | case Parameters::TARGET_64_LITTLE: |
| 4596 | this->sized_create_version_sections<64, false>(versions, symtab, |
| 4597 | local_symcount, |
| 4598 | dynamic_symbols, dynstr); |
| 4599 | break; |
| 4600 | #endif |
| 4601 | #ifdef HAVE_TARGET_64_BIG |
| 4602 | case Parameters::TARGET_64_BIG: |
| 4603 | this->sized_create_version_sections<64, true>(versions, symtab, |
| 4604 | local_symcount, |
| 4605 | dynamic_symbols, dynstr); |
| 4606 | break; |
| 4607 | #endif |
| 4608 | default: |
| 4609 | gold_unreachable(); |
| 4610 | } |
| 4611 | } |
| 4612 | |
| 4613 | // Create the version sections, sized version. |
| 4614 | |
| 4615 | template<int size, bool big_endian> |
| 4616 | void |
| 4617 | Layout::sized_create_version_sections( |
| 4618 | const Versions* versions, |
| 4619 | const Symbol_table* symtab, |
| 4620 | unsigned int local_symcount, |
| 4621 | const std::vector<Symbol*>& dynamic_symbols, |
| 4622 | const Output_section* dynstr) |
| 4623 | { |
| 4624 | Output_section* vsec = this->choose_output_section(NULL, ".gnu.version", |
| 4625 | elfcpp::SHT_GNU_versym, |
| 4626 | elfcpp::SHF_ALLOC, |
| 4627 | false, |
| 4628 | ORDER_DYNAMIC_LINKER, |
| 4629 | false, false, false); |
| 4630 | |
| 4631 | // Check for NULL since a linker script may discard this section. |
| 4632 | if (vsec != NULL) |
| 4633 | { |
| 4634 | unsigned char* vbuf; |
| 4635 | unsigned int vsize; |
| 4636 | versions->symbol_section_contents<size, big_endian>(symtab, |
| 4637 | &this->dynpool_, |
| 4638 | local_symcount, |
| 4639 | dynamic_symbols, |
| 4640 | &vbuf, &vsize); |
| 4641 | |
| 4642 | Output_section_data* vdata = new Output_data_const_buffer(vbuf, vsize, 2, |
| 4643 | "** versions"); |
| 4644 | |
| 4645 | vsec->add_output_section_data(vdata); |
| 4646 | vsec->set_entsize(2); |
| 4647 | vsec->set_link_section(this->dynsym_section_); |
| 4648 | } |
| 4649 | |
| 4650 | Output_data_dynamic* const odyn = this->dynamic_data_; |
| 4651 | if (odyn != NULL && vsec != NULL) |
| 4652 | odyn->add_section_address(elfcpp::DT_VERSYM, vsec); |
| 4653 | |
| 4654 | if (versions->any_defs()) |
| 4655 | { |
| 4656 | Output_section* vdsec; |
| 4657 | vdsec = this->choose_output_section(NULL, ".gnu.version_d", |
| 4658 | elfcpp::SHT_GNU_verdef, |
| 4659 | elfcpp::SHF_ALLOC, |
| 4660 | false, ORDER_DYNAMIC_LINKER, false, |
| 4661 | false, false); |
| 4662 | |
| 4663 | if (vdsec != NULL) |
| 4664 | { |
| 4665 | unsigned char* vdbuf; |
| 4666 | unsigned int vdsize; |
| 4667 | unsigned int vdentries; |
| 4668 | versions->def_section_contents<size, big_endian>(&this->dynpool_, |
| 4669 | &vdbuf, &vdsize, |
| 4670 | &vdentries); |
| 4671 | |
| 4672 | Output_section_data* vddata = |
| 4673 | new Output_data_const_buffer(vdbuf, vdsize, 4, "** version defs"); |
| 4674 | |
| 4675 | vdsec->add_output_section_data(vddata); |
| 4676 | vdsec->set_link_section(dynstr); |
| 4677 | vdsec->set_info(vdentries); |
| 4678 | |
| 4679 | if (odyn != NULL) |
| 4680 | { |
| 4681 | odyn->add_section_address(elfcpp::DT_VERDEF, vdsec); |
| 4682 | odyn->add_constant(elfcpp::DT_VERDEFNUM, vdentries); |
| 4683 | } |
| 4684 | } |
| 4685 | } |
| 4686 | |
| 4687 | if (versions->any_needs()) |
| 4688 | { |
| 4689 | Output_section* vnsec; |
| 4690 | vnsec = this->choose_output_section(NULL, ".gnu.version_r", |
| 4691 | elfcpp::SHT_GNU_verneed, |
| 4692 | elfcpp::SHF_ALLOC, |
| 4693 | false, ORDER_DYNAMIC_LINKER, false, |
| 4694 | false, false); |
| 4695 | |
| 4696 | if (vnsec != NULL) |
| 4697 | { |
| 4698 | unsigned char* vnbuf; |
| 4699 | unsigned int vnsize; |
| 4700 | unsigned int vnentries; |
| 4701 | versions->need_section_contents<size, big_endian>(&this->dynpool_, |
| 4702 | &vnbuf, &vnsize, |
| 4703 | &vnentries); |
| 4704 | |
| 4705 | Output_section_data* vndata = |
| 4706 | new Output_data_const_buffer(vnbuf, vnsize, 4, "** version refs"); |
| 4707 | |
| 4708 | vnsec->add_output_section_data(vndata); |
| 4709 | vnsec->set_link_section(dynstr); |
| 4710 | vnsec->set_info(vnentries); |
| 4711 | |
| 4712 | if (odyn != NULL) |
| 4713 | { |
| 4714 | odyn->add_section_address(elfcpp::DT_VERNEED, vnsec); |
| 4715 | odyn->add_constant(elfcpp::DT_VERNEEDNUM, vnentries); |
| 4716 | } |
| 4717 | } |
| 4718 | } |
| 4719 | } |
| 4720 | |
| 4721 | // Create the .interp section and PT_INTERP segment. |
| 4722 | |
| 4723 | void |
| 4724 | Layout::create_interp(const Target* target) |
| 4725 | { |
| 4726 | gold_assert(this->interp_segment_ == NULL); |
| 4727 | |
| 4728 | const char* interp = parameters->options().dynamic_linker(); |
| 4729 | if (interp == NULL) |
| 4730 | { |
| 4731 | interp = target->dynamic_linker(); |
| 4732 | gold_assert(interp != NULL); |
| 4733 | } |
| 4734 | |
| 4735 | size_t len = strlen(interp) + 1; |
| 4736 | |
| 4737 | Output_section_data* odata = new Output_data_const(interp, len, 1); |
| 4738 | |
| 4739 | Output_section* osec = this->choose_output_section(NULL, ".interp", |
| 4740 | elfcpp::SHT_PROGBITS, |
| 4741 | elfcpp::SHF_ALLOC, |
| 4742 | false, ORDER_INTERP, |
| 4743 | false, false, false); |
| 4744 | if (osec != NULL) |
| 4745 | osec->add_output_section_data(odata); |
| 4746 | } |
| 4747 | |
| 4748 | // Add dynamic tags for the PLT and the dynamic relocs. This is |
| 4749 | // called by the target-specific code. This does nothing if not doing |
| 4750 | // a dynamic link. |
| 4751 | |
| 4752 | // USE_REL is true for REL relocs rather than RELA relocs. |
| 4753 | |
| 4754 | // If PLT_GOT is not NULL, then DT_PLTGOT points to it. |
| 4755 | |
| 4756 | // If PLT_REL is not NULL, it is used for DT_PLTRELSZ, and DT_JMPREL, |
| 4757 | // and we also set DT_PLTREL. We use PLT_REL's output section, since |
| 4758 | // some targets have multiple reloc sections in PLT_REL. |
| 4759 | |
| 4760 | // If DYN_REL is not NULL, it is used for DT_REL/DT_RELA, |
| 4761 | // DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output |
| 4762 | // section. |
| 4763 | |
| 4764 | // If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an |
| 4765 | // executable. |
| 4766 | |
| 4767 | void |
| 4768 | Layout::add_target_dynamic_tags(bool use_rel, const Output_data* plt_got, |
| 4769 | const Output_data* plt_rel, |
| 4770 | const Output_data_reloc_generic* dyn_rel, |
| 4771 | bool add_debug, bool dynrel_includes_plt) |
| 4772 | { |
| 4773 | Output_data_dynamic* odyn = this->dynamic_data_; |
| 4774 | if (odyn == NULL) |
| 4775 | return; |
| 4776 | |
| 4777 | if (plt_got != NULL && plt_got->output_section() != NULL) |
| 4778 | odyn->add_section_address(elfcpp::DT_PLTGOT, plt_got); |
| 4779 | |
| 4780 | if (plt_rel != NULL && plt_rel->output_section() != NULL) |
| 4781 | { |
| 4782 | odyn->add_section_size(elfcpp::DT_PLTRELSZ, plt_rel->output_section()); |
| 4783 | odyn->add_section_address(elfcpp::DT_JMPREL, plt_rel->output_section()); |
| 4784 | odyn->add_constant(elfcpp::DT_PLTREL, |
| 4785 | use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA); |
| 4786 | } |
| 4787 | |
| 4788 | if ((dyn_rel != NULL && dyn_rel->output_section() != NULL) |
| 4789 | || (dynrel_includes_plt |
| 4790 | && plt_rel != NULL |
| 4791 | && plt_rel->output_section() != NULL)) |
| 4792 | { |
| 4793 | bool have_dyn_rel = dyn_rel != NULL && dyn_rel->output_section() != NULL; |
| 4794 | bool have_plt_rel = plt_rel != NULL && plt_rel->output_section() != NULL; |
| 4795 | odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA, |
| 4796 | (have_dyn_rel |
| 4797 | ? dyn_rel->output_section() |
| 4798 | : plt_rel->output_section())); |
| 4799 | elfcpp::DT size_tag = use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ; |
| 4800 | if (have_dyn_rel && have_plt_rel && dynrel_includes_plt) |
| 4801 | odyn->add_section_size(size_tag, |
| 4802 | dyn_rel->output_section(), |
| 4803 | plt_rel->output_section()); |
| 4804 | else if (have_dyn_rel) |
| 4805 | odyn->add_section_size(size_tag, dyn_rel->output_section()); |
| 4806 | else |
| 4807 | odyn->add_section_size(size_tag, plt_rel->output_section()); |
| 4808 | const int size = parameters->target().get_size(); |
| 4809 | elfcpp::DT rel_tag; |
| 4810 | int rel_size; |
| 4811 | if (use_rel) |
| 4812 | { |
| 4813 | rel_tag = elfcpp::DT_RELENT; |
| 4814 | if (size == 32) |
| 4815 | rel_size = Reloc_types<elfcpp::SHT_REL, 32, false>::reloc_size; |
| 4816 | else if (size == 64) |
| 4817 | rel_size = Reloc_types<elfcpp::SHT_REL, 64, false>::reloc_size; |
| 4818 | else |
| 4819 | gold_unreachable(); |
| 4820 | } |
| 4821 | else |
| 4822 | { |
| 4823 | rel_tag = elfcpp::DT_RELAENT; |
| 4824 | if (size == 32) |
| 4825 | rel_size = Reloc_types<elfcpp::SHT_RELA, 32, false>::reloc_size; |
| 4826 | else if (size == 64) |
| 4827 | rel_size = Reloc_types<elfcpp::SHT_RELA, 64, false>::reloc_size; |
| 4828 | else |
| 4829 | gold_unreachable(); |
| 4830 | } |
| 4831 | odyn->add_constant(rel_tag, rel_size); |
| 4832 | |
| 4833 | if (parameters->options().combreloc() && have_dyn_rel) |
| 4834 | { |
| 4835 | size_t c = dyn_rel->relative_reloc_count(); |
| 4836 | if (c > 0) |
| 4837 | odyn->add_constant((use_rel |
| 4838 | ? elfcpp::DT_RELCOUNT |
| 4839 | : elfcpp::DT_RELACOUNT), |
| 4840 | c); |
| 4841 | } |
| 4842 | } |
| 4843 | |
| 4844 | if (add_debug && !parameters->options().shared()) |
| 4845 | { |
| 4846 | // The value of the DT_DEBUG tag is filled in by the dynamic |
| 4847 | // linker at run time, and used by the debugger. |
| 4848 | odyn->add_constant(elfcpp::DT_DEBUG, 0); |
| 4849 | } |
| 4850 | } |
| 4851 | |
| 4852 | void |
| 4853 | Layout::add_target_specific_dynamic_tag(elfcpp::DT tag, unsigned int val) |
| 4854 | { |
| 4855 | Output_data_dynamic* odyn = this->dynamic_data_; |
| 4856 | if (odyn == NULL) |
| 4857 | return; |
| 4858 | odyn->add_constant(tag, val); |
| 4859 | } |
| 4860 | |
| 4861 | // Finish the .dynamic section and PT_DYNAMIC segment. |
| 4862 | |
| 4863 | void |
| 4864 | Layout::finish_dynamic_section(const Input_objects* input_objects, |
| 4865 | const Symbol_table* symtab) |
| 4866 | { |
| 4867 | if (!this->script_options_->saw_phdrs_clause() |
| 4868 | && this->dynamic_section_ != NULL) |
| 4869 | { |
| 4870 | Output_segment* oseg = this->make_output_segment(elfcpp::PT_DYNAMIC, |
| 4871 | (elfcpp::PF_R |
| 4872 | | elfcpp::PF_W)); |
| 4873 | oseg->add_output_section_to_nonload(this->dynamic_section_, |
| 4874 | elfcpp::PF_R | elfcpp::PF_W); |
| 4875 | } |
| 4876 | |
| 4877 | Output_data_dynamic* const odyn = this->dynamic_data_; |
| 4878 | if (odyn == NULL) |
| 4879 | return; |
| 4880 | |
| 4881 | for (Input_objects::Dynobj_iterator p = input_objects->dynobj_begin(); |
| 4882 | p != input_objects->dynobj_end(); |
| 4883 | ++p) |
| 4884 | { |
| 4885 | if (!(*p)->is_needed() && (*p)->as_needed()) |
| 4886 | { |
| 4887 | // This dynamic object was linked with --as-needed, but it |
| 4888 | // is not needed. |
| 4889 | continue; |
| 4890 | } |
| 4891 | |
| 4892 | odyn->add_string(elfcpp::DT_NEEDED, (*p)->soname()); |
| 4893 | } |
| 4894 | |
| 4895 | if (parameters->options().shared()) |
| 4896 | { |
| 4897 | const char* soname = parameters->options().soname(); |
| 4898 | if (soname != NULL) |
| 4899 | odyn->add_string(elfcpp::DT_SONAME, soname); |
| 4900 | } |
| 4901 | |
| 4902 | Symbol* sym = symtab->lookup(parameters->options().init()); |
| 4903 | if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) |
| 4904 | odyn->add_symbol(elfcpp::DT_INIT, sym); |
| 4905 | |
| 4906 | sym = symtab->lookup(parameters->options().fini()); |
| 4907 | if (sym != NULL && sym->is_defined() && !sym->is_from_dynobj()) |
| 4908 | odyn->add_symbol(elfcpp::DT_FINI, sym); |
| 4909 | |
| 4910 | // Look for .init_array, .preinit_array and .fini_array by checking |
| 4911 | // section types. |
| 4912 | for(Layout::Section_list::const_iterator p = this->section_list_.begin(); |
| 4913 | p != this->section_list_.end(); |
| 4914 | ++p) |
| 4915 | switch((*p)->type()) |
| 4916 | { |
| 4917 | case elfcpp::SHT_FINI_ARRAY: |
| 4918 | odyn->add_section_address(elfcpp::DT_FINI_ARRAY, *p); |
| 4919 | odyn->add_section_size(elfcpp::DT_FINI_ARRAYSZ, *p); |
| 4920 | break; |
| 4921 | case elfcpp::SHT_INIT_ARRAY: |
| 4922 | odyn->add_section_address(elfcpp::DT_INIT_ARRAY, *p); |
| 4923 | odyn->add_section_size(elfcpp::DT_INIT_ARRAYSZ, *p); |
| 4924 | break; |
| 4925 | case elfcpp::SHT_PREINIT_ARRAY: |
| 4926 | odyn->add_section_address(elfcpp::DT_PREINIT_ARRAY, *p); |
| 4927 | odyn->add_section_size(elfcpp::DT_PREINIT_ARRAYSZ, *p); |
| 4928 | break; |
| 4929 | default: |
| 4930 | break; |
| 4931 | } |
| 4932 | |
| 4933 | // Add a DT_RPATH entry if needed. |
| 4934 | const General_options::Dir_list& rpath(parameters->options().rpath()); |
| 4935 | if (!rpath.empty()) |
| 4936 | { |
| 4937 | std::string rpath_val; |
| 4938 | for (General_options::Dir_list::const_iterator p = rpath.begin(); |
| 4939 | p != rpath.end(); |
| 4940 | ++p) |
| 4941 | { |
| 4942 | if (rpath_val.empty()) |
| 4943 | rpath_val = p->name(); |
| 4944 | else |
| 4945 | { |
| 4946 | // Eliminate duplicates. |
| 4947 | General_options::Dir_list::const_iterator q; |
| 4948 | for (q = rpath.begin(); q != p; ++q) |
| 4949 | if (q->name() == p->name()) |
| 4950 | break; |
| 4951 | if (q == p) |
| 4952 | { |
| 4953 | rpath_val += ':'; |
| 4954 | rpath_val += p->name(); |
| 4955 | } |
| 4956 | } |
| 4957 | } |
| 4958 | |
| 4959 | if (!parameters->options().enable_new_dtags()) |
| 4960 | odyn->add_string(elfcpp::DT_RPATH, rpath_val); |
| 4961 | else |
| 4962 | odyn->add_string(elfcpp::DT_RUNPATH, rpath_val); |
| 4963 | } |
| 4964 | |
| 4965 | // Look for text segments that have dynamic relocations. |
| 4966 | bool have_textrel = false; |
| 4967 | if (!this->script_options_->saw_sections_clause()) |
| 4968 | { |
| 4969 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 4970 | p != this->segment_list_.end(); |
| 4971 | ++p) |
| 4972 | { |
| 4973 | if ((*p)->type() == elfcpp::PT_LOAD |
| 4974 | && ((*p)->flags() & elfcpp::PF_W) == 0 |
| 4975 | && (*p)->has_dynamic_reloc()) |
| 4976 | { |
| 4977 | have_textrel = true; |
| 4978 | break; |
| 4979 | } |
| 4980 | } |
| 4981 | } |
| 4982 | else |
| 4983 | { |
| 4984 | // We don't know the section -> segment mapping, so we are |
| 4985 | // conservative and just look for readonly sections with |
| 4986 | // relocations. If those sections wind up in writable segments, |
| 4987 | // then we have created an unnecessary DT_TEXTREL entry. |
| 4988 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 4989 | p != this->section_list_.end(); |
| 4990 | ++p) |
| 4991 | { |
| 4992 | if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0 |
| 4993 | && ((*p)->flags() & elfcpp::SHF_WRITE) == 0 |
| 4994 | && (*p)->has_dynamic_reloc()) |
| 4995 | { |
| 4996 | have_textrel = true; |
| 4997 | break; |
| 4998 | } |
| 4999 | } |
| 5000 | } |
| 5001 | |
| 5002 | if (parameters->options().filter() != NULL) |
| 5003 | odyn->add_string(elfcpp::DT_FILTER, parameters->options().filter()); |
| 5004 | if (parameters->options().any_auxiliary()) |
| 5005 | { |
| 5006 | for (options::String_set::const_iterator p = |
| 5007 | parameters->options().auxiliary_begin(); |
| 5008 | p != parameters->options().auxiliary_end(); |
| 5009 | ++p) |
| 5010 | odyn->add_string(elfcpp::DT_AUXILIARY, *p); |
| 5011 | } |
| 5012 | |
| 5013 | // Add a DT_FLAGS entry if necessary. |
| 5014 | unsigned int flags = 0; |
| 5015 | if (have_textrel) |
| 5016 | { |
| 5017 | // Add a DT_TEXTREL for compatibility with older loaders. |
| 5018 | odyn->add_constant(elfcpp::DT_TEXTREL, 0); |
| 5019 | flags |= elfcpp::DF_TEXTREL; |
| 5020 | |
| 5021 | if (parameters->options().text()) |
| 5022 | gold_error(_("read-only segment has dynamic relocations")); |
| 5023 | else if (parameters->options().warn_shared_textrel() |
| 5024 | && parameters->options().shared()) |
| 5025 | gold_warning(_("shared library text segment is not shareable")); |
| 5026 | } |
| 5027 | if (parameters->options().shared() && this->has_static_tls()) |
| 5028 | flags |= elfcpp::DF_STATIC_TLS; |
| 5029 | if (parameters->options().origin()) |
| 5030 | flags |= elfcpp::DF_ORIGIN; |
| 5031 | if (parameters->options().Bsymbolic() |
| 5032 | && !parameters->options().have_dynamic_list()) |
| 5033 | { |
| 5034 | flags |= elfcpp::DF_SYMBOLIC; |
| 5035 | // Add DT_SYMBOLIC for compatibility with older loaders. |
| 5036 | odyn->add_constant(elfcpp::DT_SYMBOLIC, 0); |
| 5037 | } |
| 5038 | if (parameters->options().now()) |
| 5039 | flags |= elfcpp::DF_BIND_NOW; |
| 5040 | if (flags != 0) |
| 5041 | odyn->add_constant(elfcpp::DT_FLAGS, flags); |
| 5042 | |
| 5043 | flags = 0; |
| 5044 | if (parameters->options().global()) |
| 5045 | flags |= elfcpp::DF_1_GLOBAL; |
| 5046 | if (parameters->options().initfirst()) |
| 5047 | flags |= elfcpp::DF_1_INITFIRST; |
| 5048 | if (parameters->options().interpose()) |
| 5049 | flags |= elfcpp::DF_1_INTERPOSE; |
| 5050 | if (parameters->options().loadfltr()) |
| 5051 | flags |= elfcpp::DF_1_LOADFLTR; |
| 5052 | if (parameters->options().nodefaultlib()) |
| 5053 | flags |= elfcpp::DF_1_NODEFLIB; |
| 5054 | if (parameters->options().nodelete()) |
| 5055 | flags |= elfcpp::DF_1_NODELETE; |
| 5056 | if (parameters->options().nodlopen()) |
| 5057 | flags |= elfcpp::DF_1_NOOPEN; |
| 5058 | if (parameters->options().nodump()) |
| 5059 | flags |= elfcpp::DF_1_NODUMP; |
| 5060 | if (!parameters->options().shared()) |
| 5061 | flags &= ~(elfcpp::DF_1_INITFIRST |
| 5062 | | elfcpp::DF_1_NODELETE |
| 5063 | | elfcpp::DF_1_NOOPEN); |
| 5064 | if (parameters->options().origin()) |
| 5065 | flags |= elfcpp::DF_1_ORIGIN; |
| 5066 | if (parameters->options().now()) |
| 5067 | flags |= elfcpp::DF_1_NOW; |
| 5068 | if (parameters->options().Bgroup()) |
| 5069 | flags |= elfcpp::DF_1_GROUP; |
| 5070 | if (flags != 0) |
| 5071 | odyn->add_constant(elfcpp::DT_FLAGS_1, flags); |
| 5072 | } |
| 5073 | |
| 5074 | // Set the size of the _DYNAMIC symbol table to be the size of the |
| 5075 | // dynamic data. |
| 5076 | |
| 5077 | void |
| 5078 | Layout::set_dynamic_symbol_size(const Symbol_table* symtab) |
| 5079 | { |
| 5080 | Output_data_dynamic* const odyn = this->dynamic_data_; |
| 5081 | if (odyn == NULL) |
| 5082 | return; |
| 5083 | odyn->finalize_data_size(); |
| 5084 | if (this->dynamic_symbol_ == NULL) |
| 5085 | return; |
| 5086 | off_t data_size = odyn->data_size(); |
| 5087 | const int size = parameters->target().get_size(); |
| 5088 | if (size == 32) |
| 5089 | symtab->get_sized_symbol<32>(this->dynamic_symbol_)->set_symsize(data_size); |
| 5090 | else if (size == 64) |
| 5091 | symtab->get_sized_symbol<64>(this->dynamic_symbol_)->set_symsize(data_size); |
| 5092 | else |
| 5093 | gold_unreachable(); |
| 5094 | } |
| 5095 | |
| 5096 | // The mapping of input section name prefixes to output section names. |
| 5097 | // In some cases one prefix is itself a prefix of another prefix; in |
| 5098 | // such a case the longer prefix must come first. These prefixes are |
| 5099 | // based on the GNU linker default ELF linker script. |
| 5100 | |
| 5101 | #define MAPPING_INIT(f, t) { f, sizeof(f) - 1, t, sizeof(t) - 1 } |
| 5102 | #define MAPPING_INIT_EXACT(f, t) { f, 0, t, sizeof(t) - 1 } |
| 5103 | const Layout::Section_name_mapping Layout::section_name_mapping[] = |
| 5104 | { |
| 5105 | MAPPING_INIT(".text.", ".text"), |
| 5106 | MAPPING_INIT(".rodata.", ".rodata"), |
| 5107 | MAPPING_INIT(".data.rel.ro.local.", ".data.rel.ro.local"), |
| 5108 | MAPPING_INIT_EXACT(".data.rel.ro.local", ".data.rel.ro.local"), |
| 5109 | MAPPING_INIT(".data.rel.ro.", ".data.rel.ro"), |
| 5110 | MAPPING_INIT_EXACT(".data.rel.ro", ".data.rel.ro"), |
| 5111 | MAPPING_INIT(".data.", ".data"), |
| 5112 | MAPPING_INIT(".bss.", ".bss"), |
| 5113 | MAPPING_INIT(".tdata.", ".tdata"), |
| 5114 | MAPPING_INIT(".tbss.", ".tbss"), |
| 5115 | MAPPING_INIT(".init_array.", ".init_array"), |
| 5116 | MAPPING_INIT(".fini_array.", ".fini_array"), |
| 5117 | MAPPING_INIT(".sdata.", ".sdata"), |
| 5118 | MAPPING_INIT(".sbss.", ".sbss"), |
| 5119 | // FIXME: In the GNU linker, .sbss2 and .sdata2 are handled |
| 5120 | // differently depending on whether it is creating a shared library. |
| 5121 | MAPPING_INIT(".sdata2.", ".sdata"), |
| 5122 | MAPPING_INIT(".sbss2.", ".sbss"), |
| 5123 | MAPPING_INIT(".lrodata.", ".lrodata"), |
| 5124 | MAPPING_INIT(".ldata.", ".ldata"), |
| 5125 | MAPPING_INIT(".lbss.", ".lbss"), |
| 5126 | MAPPING_INIT(".gcc_except_table.", ".gcc_except_table"), |
| 5127 | MAPPING_INIT(".gnu.linkonce.d.rel.ro.local.", ".data.rel.ro.local"), |
| 5128 | MAPPING_INIT(".gnu.linkonce.d.rel.ro.", ".data.rel.ro"), |
| 5129 | MAPPING_INIT(".gnu.linkonce.t.", ".text"), |
| 5130 | MAPPING_INIT(".gnu.linkonce.r.", ".rodata"), |
| 5131 | MAPPING_INIT(".gnu.linkonce.d.", ".data"), |
| 5132 | MAPPING_INIT(".gnu.linkonce.b.", ".bss"), |
| 5133 | MAPPING_INIT(".gnu.linkonce.s.", ".sdata"), |
| 5134 | MAPPING_INIT(".gnu.linkonce.sb.", ".sbss"), |
| 5135 | MAPPING_INIT(".gnu.linkonce.s2.", ".sdata"), |
| 5136 | MAPPING_INIT(".gnu.linkonce.sb2.", ".sbss"), |
| 5137 | MAPPING_INIT(".gnu.linkonce.wi.", ".debug_info"), |
| 5138 | MAPPING_INIT(".gnu.linkonce.td.", ".tdata"), |
| 5139 | MAPPING_INIT(".gnu.linkonce.tb.", ".tbss"), |
| 5140 | MAPPING_INIT(".gnu.linkonce.lr.", ".lrodata"), |
| 5141 | MAPPING_INIT(".gnu.linkonce.l.", ".ldata"), |
| 5142 | MAPPING_INIT(".gnu.linkonce.lb.", ".lbss"), |
| 5143 | MAPPING_INIT(".ARM.extab", ".ARM.extab"), |
| 5144 | MAPPING_INIT(".gnu.linkonce.armextab.", ".ARM.extab"), |
| 5145 | MAPPING_INIT(".ARM.exidx", ".ARM.exidx"), |
| 5146 | MAPPING_INIT(".gnu.linkonce.armexidx.", ".ARM.exidx"), |
| 5147 | }; |
| 5148 | |
| 5149 | // Mapping for ".text" section prefixes with -z,keep-text-section-prefix. |
| 5150 | const Layout::Section_name_mapping Layout::text_section_name_mapping[] = |
| 5151 | { |
| 5152 | MAPPING_INIT(".text.hot.", ".text.hot"), |
| 5153 | MAPPING_INIT_EXACT(".text.hot", ".text.hot"), |
| 5154 | MAPPING_INIT(".text.unlikely.", ".text.unlikely"), |
| 5155 | MAPPING_INIT_EXACT(".text.unlikely", ".text.unlikely"), |
| 5156 | MAPPING_INIT(".text.startup.", ".text.startup"), |
| 5157 | MAPPING_INIT_EXACT(".text.startup", ".text.startup"), |
| 5158 | MAPPING_INIT(".text.exit.", ".text.exit"), |
| 5159 | MAPPING_INIT_EXACT(".text.exit", ".text.exit"), |
| 5160 | MAPPING_INIT(".text.", ".text"), |
| 5161 | }; |
| 5162 | #undef MAPPING_INIT |
| 5163 | #undef MAPPING_INIT_EXACT |
| 5164 | |
| 5165 | const int Layout::section_name_mapping_count = |
| 5166 | (sizeof(Layout::section_name_mapping) |
| 5167 | / sizeof(Layout::section_name_mapping[0])); |
| 5168 | |
| 5169 | const int Layout::text_section_name_mapping_count = |
| 5170 | (sizeof(Layout::text_section_name_mapping) |
| 5171 | / sizeof(Layout::text_section_name_mapping[0])); |
| 5172 | |
| 5173 | // Find section name NAME in PSNM and return the mapped name if found |
| 5174 | // with the length set in PLEN. |
| 5175 | const char * |
| 5176 | Layout::match_section_name(const Layout::Section_name_mapping* psnm, |
| 5177 | const int count, |
| 5178 | const char* name, size_t* plen) |
| 5179 | { |
| 5180 | for (int i = 0; i < count; ++i, ++psnm) |
| 5181 | { |
| 5182 | if (psnm->fromlen > 0) |
| 5183 | { |
| 5184 | if (strncmp(name, psnm->from, psnm->fromlen) == 0) |
| 5185 | { |
| 5186 | *plen = psnm->tolen; |
| 5187 | return psnm->to; |
| 5188 | } |
| 5189 | } |
| 5190 | else |
| 5191 | { |
| 5192 | if (strcmp(name, psnm->from) == 0) |
| 5193 | { |
| 5194 | *plen = psnm->tolen; |
| 5195 | return psnm->to; |
| 5196 | } |
| 5197 | } |
| 5198 | } |
| 5199 | return NULL; |
| 5200 | } |
| 5201 | |
| 5202 | // Choose the output section name to use given an input section name. |
| 5203 | // Set *PLEN to the length of the name. *PLEN is initialized to the |
| 5204 | // length of NAME. |
| 5205 | |
| 5206 | const char* |
| 5207 | Layout::output_section_name(const Relobj* relobj, const char* name, |
| 5208 | size_t* plen) |
| 5209 | { |
| 5210 | // gcc 4.3 generates the following sorts of section names when it |
| 5211 | // needs a section name specific to a function: |
| 5212 | // .text.FN |
| 5213 | // .rodata.FN |
| 5214 | // .sdata2.FN |
| 5215 | // .data.FN |
| 5216 | // .data.rel.FN |
| 5217 | // .data.rel.local.FN |
| 5218 | // .data.rel.ro.FN |
| 5219 | // .data.rel.ro.local.FN |
| 5220 | // .sdata.FN |
| 5221 | // .bss.FN |
| 5222 | // .sbss.FN |
| 5223 | // .tdata.FN |
| 5224 | // .tbss.FN |
| 5225 | |
| 5226 | // The GNU linker maps all of those to the part before the .FN, |
| 5227 | // except that .data.rel.local.FN is mapped to .data, and |
| 5228 | // .data.rel.ro.local.FN is mapped to .data.rel.ro. The sections |
| 5229 | // beginning with .data.rel.ro.local are grouped together. |
| 5230 | |
| 5231 | // For an anonymous namespace, the string FN can contain a '.'. |
| 5232 | |
| 5233 | // Also of interest: .rodata.strN.N, .rodata.cstN, both of which the |
| 5234 | // GNU linker maps to .rodata. |
| 5235 | |
| 5236 | // The .data.rel.ro sections are used with -z relro. The sections |
| 5237 | // are recognized by name. We use the same names that the GNU |
| 5238 | // linker does for these sections. |
| 5239 | |
| 5240 | // It is hard to handle this in a principled way, so we don't even |
| 5241 | // try. We use a table of mappings. If the input section name is |
| 5242 | // not found in the table, we simply use it as the output section |
| 5243 | // name. |
| 5244 | |
| 5245 | if (parameters->options().keep_text_section_prefix() |
| 5246 | && is_prefix_of(".text", name)) |
| 5247 | { |
| 5248 | const char* match = match_section_name(text_section_name_mapping, |
| 5249 | text_section_name_mapping_count, |
| 5250 | name, plen); |
| 5251 | if (match != NULL) |
| 5252 | return match; |
| 5253 | } |
| 5254 | |
| 5255 | const char* match = match_section_name(section_name_mapping, |
| 5256 | section_name_mapping_count, name, plen); |
| 5257 | if (match != NULL) |
| 5258 | return match; |
| 5259 | |
| 5260 | // As an additional complication, .ctors sections are output in |
| 5261 | // either .ctors or .init_array sections, and .dtors sections are |
| 5262 | // output in either .dtors or .fini_array sections. |
| 5263 | if (is_prefix_of(".ctors.", name) || is_prefix_of(".dtors.", name)) |
| 5264 | { |
| 5265 | if (parameters->options().ctors_in_init_array()) |
| 5266 | { |
| 5267 | *plen = 11; |
| 5268 | return name[1] == 'c' ? ".init_array" : ".fini_array"; |
| 5269 | } |
| 5270 | else |
| 5271 | { |
| 5272 | *plen = 6; |
| 5273 | return name[1] == 'c' ? ".ctors" : ".dtors"; |
| 5274 | } |
| 5275 | } |
| 5276 | if (parameters->options().ctors_in_init_array() |
| 5277 | && (strcmp(name, ".ctors") == 0 || strcmp(name, ".dtors") == 0)) |
| 5278 | { |
| 5279 | // To make .init_array/.fini_array work with gcc we must exclude |
| 5280 | // .ctors and .dtors sections from the crtbegin and crtend |
| 5281 | // files. |
| 5282 | if (relobj == NULL |
| 5283 | || (!Layout::match_file_name(relobj, "crtbegin") |
| 5284 | && !Layout::match_file_name(relobj, "crtend"))) |
| 5285 | { |
| 5286 | *plen = 11; |
| 5287 | return name[1] == 'c' ? ".init_array" : ".fini_array"; |
| 5288 | } |
| 5289 | } |
| 5290 | |
| 5291 | return name; |
| 5292 | } |
| 5293 | |
| 5294 | // Return true if RELOBJ is an input file whose base name matches |
| 5295 | // FILE_NAME. The base name must have an extension of ".o", and must |
| 5296 | // be exactly FILE_NAME.o or FILE_NAME, one character, ".o". This is |
| 5297 | // to match crtbegin.o as well as crtbeginS.o without getting confused |
| 5298 | // by other possibilities. Overall matching the file name this way is |
| 5299 | // a dreadful hack, but the GNU linker does it in order to better |
| 5300 | // support gcc, and we need to be compatible. |
| 5301 | |
| 5302 | bool |
| 5303 | Layout::match_file_name(const Relobj* relobj, const char* match) |
| 5304 | { |
| 5305 | const std::string& file_name(relobj->name()); |
| 5306 | const char* base_name = lbasename(file_name.c_str()); |
| 5307 | size_t match_len = strlen(match); |
| 5308 | if (strncmp(base_name, match, match_len) != 0) |
| 5309 | return false; |
| 5310 | size_t base_len = strlen(base_name); |
| 5311 | if (base_len != match_len + 2 && base_len != match_len + 3) |
| 5312 | return false; |
| 5313 | return memcmp(base_name + base_len - 2, ".o", 2) == 0; |
| 5314 | } |
| 5315 | |
| 5316 | // Check if a comdat group or .gnu.linkonce section with the given |
| 5317 | // NAME is selected for the link. If there is already a section, |
| 5318 | // *KEPT_SECTION is set to point to the existing section and the |
| 5319 | // function returns false. Otherwise, OBJECT, SHNDX, IS_COMDAT, and |
| 5320 | // IS_GROUP_NAME are recorded for this NAME in the layout object, |
| 5321 | // *KEPT_SECTION is set to the internal copy and the function returns |
| 5322 | // true. |
| 5323 | |
| 5324 | bool |
| 5325 | Layout::find_or_add_kept_section(const std::string& name, |
| 5326 | Relobj* object, |
| 5327 | unsigned int shndx, |
| 5328 | bool is_comdat, |
| 5329 | bool is_group_name, |
| 5330 | Kept_section** kept_section) |
| 5331 | { |
| 5332 | // It's normal to see a couple of entries here, for the x86 thunk |
| 5333 | // sections. If we see more than a few, we're linking a C++ |
| 5334 | // program, and we resize to get more space to minimize rehashing. |
| 5335 | if (this->signatures_.size() > 4 |
| 5336 | && !this->resized_signatures_) |
| 5337 | { |
| 5338 | reserve_unordered_map(&this->signatures_, |
| 5339 | this->number_of_input_files_ * 64); |
| 5340 | this->resized_signatures_ = true; |
| 5341 | } |
| 5342 | |
| 5343 | Kept_section candidate; |
| 5344 | std::pair<Signatures::iterator, bool> ins = |
| 5345 | this->signatures_.insert(std::make_pair(name, candidate)); |
| 5346 | |
| 5347 | if (kept_section != NULL) |
| 5348 | *kept_section = &ins.first->second; |
| 5349 | if (ins.second) |
| 5350 | { |
| 5351 | // This is the first time we've seen this signature. |
| 5352 | ins.first->second.set_object(object); |
| 5353 | ins.first->second.set_shndx(shndx); |
| 5354 | if (is_comdat) |
| 5355 | ins.first->second.set_is_comdat(); |
| 5356 | if (is_group_name) |
| 5357 | ins.first->second.set_is_group_name(); |
| 5358 | return true; |
| 5359 | } |
| 5360 | |
| 5361 | // We have already seen this signature. |
| 5362 | |
| 5363 | if (ins.first->second.is_group_name()) |
| 5364 | { |
| 5365 | // We've already seen a real section group with this signature. |
| 5366 | // If the kept group is from a plugin object, and we're in the |
| 5367 | // replacement phase, accept the new one as a replacement. |
| 5368 | if (ins.first->second.object() == NULL |
| 5369 | && parameters->options().plugins()->in_replacement_phase()) |
| 5370 | { |
| 5371 | ins.first->second.set_object(object); |
| 5372 | ins.first->second.set_shndx(shndx); |
| 5373 | return true; |
| 5374 | } |
| 5375 | return false; |
| 5376 | } |
| 5377 | else if (is_group_name) |
| 5378 | { |
| 5379 | // This is a real section group, and we've already seen a |
| 5380 | // linkonce section with this signature. Record that we've seen |
| 5381 | // a section group, and don't include this section group. |
| 5382 | ins.first->second.set_is_group_name(); |
| 5383 | return false; |
| 5384 | } |
| 5385 | else |
| 5386 | { |
| 5387 | // We've already seen a linkonce section and this is a linkonce |
| 5388 | // section. These don't block each other--this may be the same |
| 5389 | // symbol name with different section types. |
| 5390 | return true; |
| 5391 | } |
| 5392 | } |
| 5393 | |
| 5394 | // Store the allocated sections into the section list. |
| 5395 | |
| 5396 | void |
| 5397 | Layout::get_allocated_sections(Section_list* section_list) const |
| 5398 | { |
| 5399 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5400 | p != this->section_list_.end(); |
| 5401 | ++p) |
| 5402 | if (((*p)->flags() & elfcpp::SHF_ALLOC) != 0) |
| 5403 | section_list->push_back(*p); |
| 5404 | } |
| 5405 | |
| 5406 | // Store the executable sections into the section list. |
| 5407 | |
| 5408 | void |
| 5409 | Layout::get_executable_sections(Section_list* section_list) const |
| 5410 | { |
| 5411 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5412 | p != this->section_list_.end(); |
| 5413 | ++p) |
| 5414 | if (((*p)->flags() & (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)) |
| 5415 | == (elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR)) |
| 5416 | section_list->push_back(*p); |
| 5417 | } |
| 5418 | |
| 5419 | // Create an output segment. |
| 5420 | |
| 5421 | Output_segment* |
| 5422 | Layout::make_output_segment(elfcpp::Elf_Word type, elfcpp::Elf_Word flags) |
| 5423 | { |
| 5424 | gold_assert(!parameters->options().relocatable()); |
| 5425 | Output_segment* oseg = new Output_segment(type, flags); |
| 5426 | this->segment_list_.push_back(oseg); |
| 5427 | |
| 5428 | if (type == elfcpp::PT_TLS) |
| 5429 | this->tls_segment_ = oseg; |
| 5430 | else if (type == elfcpp::PT_GNU_RELRO) |
| 5431 | this->relro_segment_ = oseg; |
| 5432 | else if (type == elfcpp::PT_INTERP) |
| 5433 | this->interp_segment_ = oseg; |
| 5434 | |
| 5435 | return oseg; |
| 5436 | } |
| 5437 | |
| 5438 | // Return the file offset of the normal symbol table. |
| 5439 | |
| 5440 | off_t |
| 5441 | Layout::symtab_section_offset() const |
| 5442 | { |
| 5443 | if (this->symtab_section_ != NULL) |
| 5444 | return this->symtab_section_->offset(); |
| 5445 | return 0; |
| 5446 | } |
| 5447 | |
| 5448 | // Return the section index of the normal symbol table. It may have |
| 5449 | // been stripped by the -s/--strip-all option. |
| 5450 | |
| 5451 | unsigned int |
| 5452 | Layout::symtab_section_shndx() const |
| 5453 | { |
| 5454 | if (this->symtab_section_ != NULL) |
| 5455 | return this->symtab_section_->out_shndx(); |
| 5456 | return 0; |
| 5457 | } |
| 5458 | |
| 5459 | // Write out the Output_sections. Most won't have anything to write, |
| 5460 | // since most of the data will come from input sections which are |
| 5461 | // handled elsewhere. But some Output_sections do have Output_data. |
| 5462 | |
| 5463 | void |
| 5464 | Layout::write_output_sections(Output_file* of) const |
| 5465 | { |
| 5466 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5467 | p != this->section_list_.end(); |
| 5468 | ++p) |
| 5469 | { |
| 5470 | if (!(*p)->after_input_sections()) |
| 5471 | (*p)->write(of); |
| 5472 | } |
| 5473 | } |
| 5474 | |
| 5475 | // Write out data not associated with a section or the symbol table. |
| 5476 | |
| 5477 | void |
| 5478 | Layout::write_data(const Symbol_table* symtab, Output_file* of) const |
| 5479 | { |
| 5480 | if (!parameters->options().strip_all()) |
| 5481 | { |
| 5482 | const Output_section* symtab_section = this->symtab_section_; |
| 5483 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5484 | p != this->section_list_.end(); |
| 5485 | ++p) |
| 5486 | { |
| 5487 | if ((*p)->needs_symtab_index()) |
| 5488 | { |
| 5489 | gold_assert(symtab_section != NULL); |
| 5490 | unsigned int index = (*p)->symtab_index(); |
| 5491 | gold_assert(index > 0 && index != -1U); |
| 5492 | off_t off = (symtab_section->offset() |
| 5493 | + index * symtab_section->entsize()); |
| 5494 | symtab->write_section_symbol(*p, this->symtab_xindex_, of, off); |
| 5495 | } |
| 5496 | } |
| 5497 | } |
| 5498 | |
| 5499 | const Output_section* dynsym_section = this->dynsym_section_; |
| 5500 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5501 | p != this->section_list_.end(); |
| 5502 | ++p) |
| 5503 | { |
| 5504 | if ((*p)->needs_dynsym_index()) |
| 5505 | { |
| 5506 | gold_assert(dynsym_section != NULL); |
| 5507 | unsigned int index = (*p)->dynsym_index(); |
| 5508 | gold_assert(index > 0 && index != -1U); |
| 5509 | off_t off = (dynsym_section->offset() |
| 5510 | + index * dynsym_section->entsize()); |
| 5511 | symtab->write_section_symbol(*p, this->dynsym_xindex_, of, off); |
| 5512 | } |
| 5513 | } |
| 5514 | |
| 5515 | // Write out the Output_data which are not in an Output_section. |
| 5516 | for (Data_list::const_iterator p = this->special_output_list_.begin(); |
| 5517 | p != this->special_output_list_.end(); |
| 5518 | ++p) |
| 5519 | (*p)->write(of); |
| 5520 | |
| 5521 | // Write out the Output_data which are not in an Output_section |
| 5522 | // and are regenerated in each iteration of relaxation. |
| 5523 | for (Data_list::const_iterator p = this->relax_output_list_.begin(); |
| 5524 | p != this->relax_output_list_.end(); |
| 5525 | ++p) |
| 5526 | (*p)->write(of); |
| 5527 | } |
| 5528 | |
| 5529 | // Write out the Output_sections which can only be written after the |
| 5530 | // input sections are complete. |
| 5531 | |
| 5532 | void |
| 5533 | Layout::write_sections_after_input_sections(Output_file* of) |
| 5534 | { |
| 5535 | // Determine the final section offsets, and thus the final output |
| 5536 | // file size. Note we finalize the .shstrab last, to allow the |
| 5537 | // after_input_section sections to modify their section-names before |
| 5538 | // writing. |
| 5539 | if (this->any_postprocessing_sections_) |
| 5540 | { |
| 5541 | off_t off = this->output_file_size_; |
| 5542 | off = this->set_section_offsets(off, POSTPROCESSING_SECTIONS_PASS); |
| 5543 | |
| 5544 | // Now that we've finalized the names, we can finalize the shstrab. |
| 5545 | off = |
| 5546 | this->set_section_offsets(off, |
| 5547 | STRTAB_AFTER_POSTPROCESSING_SECTIONS_PASS); |
| 5548 | |
| 5549 | if (off > this->output_file_size_) |
| 5550 | { |
| 5551 | of->resize(off); |
| 5552 | this->output_file_size_ = off; |
| 5553 | } |
| 5554 | } |
| 5555 | |
| 5556 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5557 | p != this->section_list_.end(); |
| 5558 | ++p) |
| 5559 | { |
| 5560 | if ((*p)->after_input_sections()) |
| 5561 | (*p)->write(of); |
| 5562 | } |
| 5563 | |
| 5564 | this->section_headers_->write(of); |
| 5565 | } |
| 5566 | |
| 5567 | // If a tree-style build ID was requested, the parallel part of that computation |
| 5568 | // is already done, and the final hash-of-hashes is computed here. For other |
| 5569 | // types of build IDs, all the work is done here. |
| 5570 | |
| 5571 | void |
| 5572 | Layout::write_build_id(Output_file* of, unsigned char* array_of_hashes, |
| 5573 | size_t size_of_hashes) const |
| 5574 | { |
| 5575 | if (this->build_id_note_ == NULL) |
| 5576 | return; |
| 5577 | |
| 5578 | unsigned char* ov = of->get_output_view(this->build_id_note_->offset(), |
| 5579 | this->build_id_note_->data_size()); |
| 5580 | |
| 5581 | if (array_of_hashes == NULL) |
| 5582 | { |
| 5583 | const size_t output_file_size = this->output_file_size(); |
| 5584 | const unsigned char* iv = of->get_input_view(0, output_file_size); |
| 5585 | const char* style = parameters->options().build_id(); |
| 5586 | |
| 5587 | // If we get here with style == "tree" then the output must be |
| 5588 | // too small for chunking, and we use SHA-1 in that case. |
| 5589 | if ((strcmp(style, "sha1") == 0) || (strcmp(style, "tree") == 0)) |
| 5590 | sha1_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov); |
| 5591 | else if (strcmp(style, "md5") == 0) |
| 5592 | md5_buffer(reinterpret_cast<const char*>(iv), output_file_size, ov); |
| 5593 | else |
| 5594 | gold_unreachable(); |
| 5595 | |
| 5596 | of->free_input_view(0, output_file_size, iv); |
| 5597 | } |
| 5598 | else |
| 5599 | { |
| 5600 | // Non-overlapping substrings of the output file have been hashed. |
| 5601 | // Compute SHA-1 hash of the hashes. |
| 5602 | sha1_buffer(reinterpret_cast<const char*>(array_of_hashes), |
| 5603 | size_of_hashes, ov); |
| 5604 | delete[] array_of_hashes; |
| 5605 | } |
| 5606 | |
| 5607 | of->write_output_view(this->build_id_note_->offset(), |
| 5608 | this->build_id_note_->data_size(), |
| 5609 | ov); |
| 5610 | } |
| 5611 | |
| 5612 | // Write out a binary file. This is called after the link is |
| 5613 | // complete. IN is the temporary output file we used to generate the |
| 5614 | // ELF code. We simply walk through the segments, read them from |
| 5615 | // their file offset in IN, and write them to their load address in |
| 5616 | // the output file. FIXME: with a bit more work, we could support |
| 5617 | // S-records and/or Intel hex format here. |
| 5618 | |
| 5619 | void |
| 5620 | Layout::write_binary(Output_file* in) const |
| 5621 | { |
| 5622 | gold_assert(parameters->options().oformat_enum() |
| 5623 | == General_options::OBJECT_FORMAT_BINARY); |
| 5624 | |
| 5625 | // Get the size of the binary file. |
| 5626 | uint64_t max_load_address = 0; |
| 5627 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 5628 | p != this->segment_list_.end(); |
| 5629 | ++p) |
| 5630 | { |
| 5631 | if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0) |
| 5632 | { |
| 5633 | uint64_t max_paddr = (*p)->paddr() + (*p)->filesz(); |
| 5634 | if (max_paddr > max_load_address) |
| 5635 | max_load_address = max_paddr; |
| 5636 | } |
| 5637 | } |
| 5638 | |
| 5639 | Output_file out(parameters->options().output_file_name()); |
| 5640 | out.open(max_load_address); |
| 5641 | |
| 5642 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 5643 | p != this->segment_list_.end(); |
| 5644 | ++p) |
| 5645 | { |
| 5646 | if ((*p)->type() == elfcpp::PT_LOAD && (*p)->filesz() > 0) |
| 5647 | { |
| 5648 | const unsigned char* vin = in->get_input_view((*p)->offset(), |
| 5649 | (*p)->filesz()); |
| 5650 | unsigned char* vout = out.get_output_view((*p)->paddr(), |
| 5651 | (*p)->filesz()); |
| 5652 | memcpy(vout, vin, (*p)->filesz()); |
| 5653 | out.write_output_view((*p)->paddr(), (*p)->filesz(), vout); |
| 5654 | in->free_input_view((*p)->offset(), (*p)->filesz(), vin); |
| 5655 | } |
| 5656 | } |
| 5657 | |
| 5658 | out.close(); |
| 5659 | } |
| 5660 | |
| 5661 | // Print the output sections to the map file. |
| 5662 | |
| 5663 | void |
| 5664 | Layout::print_to_mapfile(Mapfile* mapfile) const |
| 5665 | { |
| 5666 | for (Segment_list::const_iterator p = this->segment_list_.begin(); |
| 5667 | p != this->segment_list_.end(); |
| 5668 | ++p) |
| 5669 | (*p)->print_sections_to_mapfile(mapfile); |
| 5670 | for (Section_list::const_iterator p = this->unattached_section_list_.begin(); |
| 5671 | p != this->unattached_section_list_.end(); |
| 5672 | ++p) |
| 5673 | (*p)->print_to_mapfile(mapfile); |
| 5674 | } |
| 5675 | |
| 5676 | // Print statistical information to stderr. This is used for --stats. |
| 5677 | |
| 5678 | void |
| 5679 | Layout::print_stats() const |
| 5680 | { |
| 5681 | this->namepool_.print_stats("section name pool"); |
| 5682 | this->sympool_.print_stats("output symbol name pool"); |
| 5683 | this->dynpool_.print_stats("dynamic name pool"); |
| 5684 | |
| 5685 | for (Section_list::const_iterator p = this->section_list_.begin(); |
| 5686 | p != this->section_list_.end(); |
| 5687 | ++p) |
| 5688 | (*p)->print_merge_stats(); |
| 5689 | } |
| 5690 | |
| 5691 | // Write_sections_task methods. |
| 5692 | |
| 5693 | // We can always run this task. |
| 5694 | |
| 5695 | Task_token* |
| 5696 | Write_sections_task::is_runnable() |
| 5697 | { |
| 5698 | return NULL; |
| 5699 | } |
| 5700 | |
| 5701 | // We need to unlock both OUTPUT_SECTIONS_BLOCKER and FINAL_BLOCKER |
| 5702 | // when finished. |
| 5703 | |
| 5704 | void |
| 5705 | Write_sections_task::locks(Task_locker* tl) |
| 5706 | { |
| 5707 | tl->add(this, this->output_sections_blocker_); |
| 5708 | if (this->input_sections_blocker_ != NULL) |
| 5709 | tl->add(this, this->input_sections_blocker_); |
| 5710 | tl->add(this, this->final_blocker_); |
| 5711 | } |
| 5712 | |
| 5713 | // Run the task--write out the data. |
| 5714 | |
| 5715 | void |
| 5716 | Write_sections_task::run(Workqueue*) |
| 5717 | { |
| 5718 | this->layout_->write_output_sections(this->of_); |
| 5719 | } |
| 5720 | |
| 5721 | // Write_data_task methods. |
| 5722 | |
| 5723 | // We can always run this task. |
| 5724 | |
| 5725 | Task_token* |
| 5726 | Write_data_task::is_runnable() |
| 5727 | { |
| 5728 | return NULL; |
| 5729 | } |
| 5730 | |
| 5731 | // We need to unlock FINAL_BLOCKER when finished. |
| 5732 | |
| 5733 | void |
| 5734 | Write_data_task::locks(Task_locker* tl) |
| 5735 | { |
| 5736 | tl->add(this, this->final_blocker_); |
| 5737 | } |
| 5738 | |
| 5739 | // Run the task--write out the data. |
| 5740 | |
| 5741 | void |
| 5742 | Write_data_task::run(Workqueue*) |
| 5743 | { |
| 5744 | this->layout_->write_data(this->symtab_, this->of_); |
| 5745 | } |
| 5746 | |
| 5747 | // Write_symbols_task methods. |
| 5748 | |
| 5749 | // We can always run this task. |
| 5750 | |
| 5751 | Task_token* |
| 5752 | Write_symbols_task::is_runnable() |
| 5753 | { |
| 5754 | return NULL; |
| 5755 | } |
| 5756 | |
| 5757 | // We need to unlock FINAL_BLOCKER when finished. |
| 5758 | |
| 5759 | void |
| 5760 | Write_symbols_task::locks(Task_locker* tl) |
| 5761 | { |
| 5762 | tl->add(this, this->final_blocker_); |
| 5763 | } |
| 5764 | |
| 5765 | // Run the task--write out the symbols. |
| 5766 | |
| 5767 | void |
| 5768 | Write_symbols_task::run(Workqueue*) |
| 5769 | { |
| 5770 | this->symtab_->write_globals(this->sympool_, this->dynpool_, |
| 5771 | this->layout_->symtab_xindex(), |
| 5772 | this->layout_->dynsym_xindex(), this->of_); |
| 5773 | } |
| 5774 | |
| 5775 | // Write_after_input_sections_task methods. |
| 5776 | |
| 5777 | // We can only run this task after the input sections have completed. |
| 5778 | |
| 5779 | Task_token* |
| 5780 | Write_after_input_sections_task::is_runnable() |
| 5781 | { |
| 5782 | if (this->input_sections_blocker_->is_blocked()) |
| 5783 | return this->input_sections_blocker_; |
| 5784 | return NULL; |
| 5785 | } |
| 5786 | |
| 5787 | // We need to unlock FINAL_BLOCKER when finished. |
| 5788 | |
| 5789 | void |
| 5790 | Write_after_input_sections_task::locks(Task_locker* tl) |
| 5791 | { |
| 5792 | tl->add(this, this->final_blocker_); |
| 5793 | } |
| 5794 | |
| 5795 | // Run the task. |
| 5796 | |
| 5797 | void |
| 5798 | Write_after_input_sections_task::run(Workqueue*) |
| 5799 | { |
| 5800 | this->layout_->write_sections_after_input_sections(this->of_); |
| 5801 | } |
| 5802 | |
| 5803 | // Build IDs can be computed as a "flat" sha1 or md5 of a string of bytes, |
| 5804 | // or as a "tree" where each chunk of the string is hashed and then those |
| 5805 | // hashes are put into a (much smaller) string which is hashed with sha1. |
| 5806 | // We compute a checksum over the entire file because that is simplest. |
| 5807 | |
| 5808 | void |
| 5809 | Build_id_task_runner::run(Workqueue* workqueue, const Task*) |
| 5810 | { |
| 5811 | Task_token* post_hash_tasks_blocker = new Task_token(true); |
| 5812 | const Layout* layout = this->layout_; |
| 5813 | Output_file* of = this->of_; |
| 5814 | const size_t filesize = (layout->output_file_size() <= 0 ? 0 |
| 5815 | : static_cast<size_t>(layout->output_file_size())); |
| 5816 | unsigned char* array_of_hashes = NULL; |
| 5817 | size_t size_of_hashes = 0; |
| 5818 | |
| 5819 | if (strcmp(this->options_->build_id(), "tree") == 0 |
| 5820 | && this->options_->build_id_chunk_size_for_treehash() > 0 |
| 5821 | && filesize > 0 |
| 5822 | && (filesize >= this->options_->build_id_min_file_size_for_treehash())) |
| 5823 | { |
| 5824 | static const size_t MD5_OUTPUT_SIZE_IN_BYTES = 16; |
| 5825 | const size_t chunk_size = |
| 5826 | this->options_->build_id_chunk_size_for_treehash(); |
| 5827 | const size_t num_hashes = ((filesize - 1) / chunk_size) + 1; |
| 5828 | post_hash_tasks_blocker->add_blockers(num_hashes); |
| 5829 | size_of_hashes = num_hashes * MD5_OUTPUT_SIZE_IN_BYTES; |
| 5830 | array_of_hashes = new unsigned char[size_of_hashes]; |
| 5831 | unsigned char *dst = array_of_hashes; |
| 5832 | for (size_t i = 0, src_offset = 0; i < num_hashes; |
| 5833 | i++, dst += MD5_OUTPUT_SIZE_IN_BYTES, src_offset += chunk_size) |
| 5834 | { |
| 5835 | size_t size = std::min(chunk_size, filesize - src_offset); |
| 5836 | workqueue->queue(new Hash_task(of, |
| 5837 | src_offset, |
| 5838 | size, |
| 5839 | dst, |
| 5840 | post_hash_tasks_blocker)); |
| 5841 | } |
| 5842 | } |
| 5843 | |
| 5844 | // Queue the final task to write the build id and close the output file. |
| 5845 | workqueue->queue(new Task_function(new Close_task_runner(this->options_, |
| 5846 | layout, |
| 5847 | of, |
| 5848 | array_of_hashes, |
| 5849 | size_of_hashes), |
| 5850 | post_hash_tasks_blocker, |
| 5851 | "Task_function Close_task_runner")); |
| 5852 | } |
| 5853 | |
| 5854 | // Close_task_runner methods. |
| 5855 | |
| 5856 | // Finish up the build ID computation, if necessary, and write a binary file, |
| 5857 | // if necessary. Then close the output file. |
| 5858 | |
| 5859 | void |
| 5860 | Close_task_runner::run(Workqueue*, const Task*) |
| 5861 | { |
| 5862 | // At this point the multi-threaded part of the build ID computation, |
| 5863 | // if any, is done. See Build_id_task_runner. |
| 5864 | this->layout_->write_build_id(this->of_, this->array_of_hashes_, |
| 5865 | this->size_of_hashes_); |
| 5866 | |
| 5867 | // If we've been asked to create a binary file, we do so here. |
| 5868 | if (this->options_->oformat_enum() != General_options::OBJECT_FORMAT_ELF) |
| 5869 | this->layout_->write_binary(this->of_); |
| 5870 | |
| 5871 | this->of_->close(); |
| 5872 | } |
| 5873 | |
| 5874 | // Instantiate the templates we need. We could use the configure |
| 5875 | // script to restrict this to only the ones for implemented targets. |
| 5876 | |
| 5877 | #ifdef HAVE_TARGET_32_LITTLE |
| 5878 | template |
| 5879 | Output_section* |
| 5880 | Layout::init_fixed_output_section<32, false>( |
| 5881 | const char* name, |
| 5882 | elfcpp::Shdr<32, false>& shdr); |
| 5883 | #endif |
| 5884 | |
| 5885 | #ifdef HAVE_TARGET_32_BIG |
| 5886 | template |
| 5887 | Output_section* |
| 5888 | Layout::init_fixed_output_section<32, true>( |
| 5889 | const char* name, |
| 5890 | elfcpp::Shdr<32, true>& shdr); |
| 5891 | #endif |
| 5892 | |
| 5893 | #ifdef HAVE_TARGET_64_LITTLE |
| 5894 | template |
| 5895 | Output_section* |
| 5896 | Layout::init_fixed_output_section<64, false>( |
| 5897 | const char* name, |
| 5898 | elfcpp::Shdr<64, false>& shdr); |
| 5899 | #endif |
| 5900 | |
| 5901 | #ifdef HAVE_TARGET_64_BIG |
| 5902 | template |
| 5903 | Output_section* |
| 5904 | Layout::init_fixed_output_section<64, true>( |
| 5905 | const char* name, |
| 5906 | elfcpp::Shdr<64, true>& shdr); |
| 5907 | #endif |
| 5908 | |
| 5909 | #ifdef HAVE_TARGET_32_LITTLE |
| 5910 | template |
| 5911 | Output_section* |
| 5912 | Layout::layout<32, false>(Sized_relobj_file<32, false>* object, |
| 5913 | unsigned int shndx, |
| 5914 | const char* name, |
| 5915 | const elfcpp::Shdr<32, false>& shdr, |
| 5916 | unsigned int, unsigned int, unsigned int, off_t*); |
| 5917 | #endif |
| 5918 | |
| 5919 | #ifdef HAVE_TARGET_32_BIG |
| 5920 | template |
| 5921 | Output_section* |
| 5922 | Layout::layout<32, true>(Sized_relobj_file<32, true>* object, |
| 5923 | unsigned int shndx, |
| 5924 | const char* name, |
| 5925 | const elfcpp::Shdr<32, true>& shdr, |
| 5926 | unsigned int, unsigned int, unsigned int, off_t*); |
| 5927 | #endif |
| 5928 | |
| 5929 | #ifdef HAVE_TARGET_64_LITTLE |
| 5930 | template |
| 5931 | Output_section* |
| 5932 | Layout::layout<64, false>(Sized_relobj_file<64, false>* object, |
| 5933 | unsigned int shndx, |
| 5934 | const char* name, |
| 5935 | const elfcpp::Shdr<64, false>& shdr, |
| 5936 | unsigned int, unsigned int, unsigned int, off_t*); |
| 5937 | #endif |
| 5938 | |
| 5939 | #ifdef HAVE_TARGET_64_BIG |
| 5940 | template |
| 5941 | Output_section* |
| 5942 | Layout::layout<64, true>(Sized_relobj_file<64, true>* object, |
| 5943 | unsigned int shndx, |
| 5944 | const char* name, |
| 5945 | const elfcpp::Shdr<64, true>& shdr, |
| 5946 | unsigned int, unsigned int, unsigned int, off_t*); |
| 5947 | #endif |
| 5948 | |
| 5949 | #ifdef HAVE_TARGET_32_LITTLE |
| 5950 | template |
| 5951 | Output_section* |
| 5952 | Layout::layout_reloc<32, false>(Sized_relobj_file<32, false>* object, |
| 5953 | unsigned int reloc_shndx, |
| 5954 | const elfcpp::Shdr<32, false>& shdr, |
| 5955 | Output_section* data_section, |
| 5956 | Relocatable_relocs* rr); |
| 5957 | #endif |
| 5958 | |
| 5959 | #ifdef HAVE_TARGET_32_BIG |
| 5960 | template |
| 5961 | Output_section* |
| 5962 | Layout::layout_reloc<32, true>(Sized_relobj_file<32, true>* object, |
| 5963 | unsigned int reloc_shndx, |
| 5964 | const elfcpp::Shdr<32, true>& shdr, |
| 5965 | Output_section* data_section, |
| 5966 | Relocatable_relocs* rr); |
| 5967 | #endif |
| 5968 | |
| 5969 | #ifdef HAVE_TARGET_64_LITTLE |
| 5970 | template |
| 5971 | Output_section* |
| 5972 | Layout::layout_reloc<64, false>(Sized_relobj_file<64, false>* object, |
| 5973 | unsigned int reloc_shndx, |
| 5974 | const elfcpp::Shdr<64, false>& shdr, |
| 5975 | Output_section* data_section, |
| 5976 | Relocatable_relocs* rr); |
| 5977 | #endif |
| 5978 | |
| 5979 | #ifdef HAVE_TARGET_64_BIG |
| 5980 | template |
| 5981 | Output_section* |
| 5982 | Layout::layout_reloc<64, true>(Sized_relobj_file<64, true>* object, |
| 5983 | unsigned int reloc_shndx, |
| 5984 | const elfcpp::Shdr<64, true>& shdr, |
| 5985 | Output_section* data_section, |
| 5986 | Relocatable_relocs* rr); |
| 5987 | #endif |
| 5988 | |
| 5989 | #ifdef HAVE_TARGET_32_LITTLE |
| 5990 | template |
| 5991 | void |
| 5992 | Layout::layout_group<32, false>(Symbol_table* symtab, |
| 5993 | Sized_relobj_file<32, false>* object, |
| 5994 | unsigned int, |
| 5995 | const char* group_section_name, |
| 5996 | const char* signature, |
| 5997 | const elfcpp::Shdr<32, false>& shdr, |
| 5998 | elfcpp::Elf_Word flags, |
| 5999 | std::vector<unsigned int>* shndxes); |
| 6000 | #endif |
| 6001 | |
| 6002 | #ifdef HAVE_TARGET_32_BIG |
| 6003 | template |
| 6004 | void |
| 6005 | Layout::layout_group<32, true>(Symbol_table* symtab, |
| 6006 | Sized_relobj_file<32, true>* object, |
| 6007 | unsigned int, |
| 6008 | const char* group_section_name, |
| 6009 | const char* signature, |
| 6010 | const elfcpp::Shdr<32, true>& shdr, |
| 6011 | elfcpp::Elf_Word flags, |
| 6012 | std::vector<unsigned int>* shndxes); |
| 6013 | #endif |
| 6014 | |
| 6015 | #ifdef HAVE_TARGET_64_LITTLE |
| 6016 | template |
| 6017 | void |
| 6018 | Layout::layout_group<64, false>(Symbol_table* symtab, |
| 6019 | Sized_relobj_file<64, false>* object, |
| 6020 | unsigned int, |
| 6021 | const char* group_section_name, |
| 6022 | const char* signature, |
| 6023 | const elfcpp::Shdr<64, false>& shdr, |
| 6024 | elfcpp::Elf_Word flags, |
| 6025 | std::vector<unsigned int>* shndxes); |
| 6026 | #endif |
| 6027 | |
| 6028 | #ifdef HAVE_TARGET_64_BIG |
| 6029 | template |
| 6030 | void |
| 6031 | Layout::layout_group<64, true>(Symbol_table* symtab, |
| 6032 | Sized_relobj_file<64, true>* object, |
| 6033 | unsigned int, |
| 6034 | const char* group_section_name, |
| 6035 | const char* signature, |
| 6036 | const elfcpp::Shdr<64, true>& shdr, |
| 6037 | elfcpp::Elf_Word flags, |
| 6038 | std::vector<unsigned int>* shndxes); |
| 6039 | #endif |
| 6040 | |
| 6041 | #ifdef HAVE_TARGET_32_LITTLE |
| 6042 | template |
| 6043 | Output_section* |
| 6044 | Layout::layout_eh_frame<32, false>(Sized_relobj_file<32, false>* object, |
| 6045 | const unsigned char* symbols, |
| 6046 | off_t symbols_size, |
| 6047 | const unsigned char* symbol_names, |
| 6048 | off_t symbol_names_size, |
| 6049 | unsigned int shndx, |
| 6050 | const elfcpp::Shdr<32, false>& shdr, |
| 6051 | unsigned int reloc_shndx, |
| 6052 | unsigned int reloc_type, |
| 6053 | off_t* off); |
| 6054 | #endif |
| 6055 | |
| 6056 | #ifdef HAVE_TARGET_32_BIG |
| 6057 | template |
| 6058 | Output_section* |
| 6059 | Layout::layout_eh_frame<32, true>(Sized_relobj_file<32, true>* object, |
| 6060 | const unsigned char* symbols, |
| 6061 | off_t symbols_size, |
| 6062 | const unsigned char* symbol_names, |
| 6063 | off_t symbol_names_size, |
| 6064 | unsigned int shndx, |
| 6065 | const elfcpp::Shdr<32, true>& shdr, |
| 6066 | unsigned int reloc_shndx, |
| 6067 | unsigned int reloc_type, |
| 6068 | off_t* off); |
| 6069 | #endif |
| 6070 | |
| 6071 | #ifdef HAVE_TARGET_64_LITTLE |
| 6072 | template |
| 6073 | Output_section* |
| 6074 | Layout::layout_eh_frame<64, false>(Sized_relobj_file<64, false>* object, |
| 6075 | const unsigned char* symbols, |
| 6076 | off_t symbols_size, |
| 6077 | const unsigned char* symbol_names, |
| 6078 | off_t symbol_names_size, |
| 6079 | unsigned int shndx, |
| 6080 | const elfcpp::Shdr<64, false>& shdr, |
| 6081 | unsigned int reloc_shndx, |
| 6082 | unsigned int reloc_type, |
| 6083 | off_t* off); |
| 6084 | #endif |
| 6085 | |
| 6086 | #ifdef HAVE_TARGET_64_BIG |
| 6087 | template |
| 6088 | Output_section* |
| 6089 | Layout::layout_eh_frame<64, true>(Sized_relobj_file<64, true>* object, |
| 6090 | const unsigned char* symbols, |
| 6091 | off_t symbols_size, |
| 6092 | const unsigned char* symbol_names, |
| 6093 | off_t symbol_names_size, |
| 6094 | unsigned int shndx, |
| 6095 | const elfcpp::Shdr<64, true>& shdr, |
| 6096 | unsigned int reloc_shndx, |
| 6097 | unsigned int reloc_type, |
| 6098 | off_t* off); |
| 6099 | #endif |
| 6100 | |
| 6101 | #ifdef HAVE_TARGET_32_LITTLE |
| 6102 | template |
| 6103 | void |
| 6104 | Layout::add_to_gdb_index(bool is_type_unit, |
| 6105 | Sized_relobj<32, false>* object, |
| 6106 | const unsigned char* symbols, |
| 6107 | off_t symbols_size, |
| 6108 | unsigned int shndx, |
| 6109 | unsigned int reloc_shndx, |
| 6110 | unsigned int reloc_type); |
| 6111 | #endif |
| 6112 | |
| 6113 | #ifdef HAVE_TARGET_32_BIG |
| 6114 | template |
| 6115 | void |
| 6116 | Layout::add_to_gdb_index(bool is_type_unit, |
| 6117 | Sized_relobj<32, true>* object, |
| 6118 | const unsigned char* symbols, |
| 6119 | off_t symbols_size, |
| 6120 | unsigned int shndx, |
| 6121 | unsigned int reloc_shndx, |
| 6122 | unsigned int reloc_type); |
| 6123 | #endif |
| 6124 | |
| 6125 | #ifdef HAVE_TARGET_64_LITTLE |
| 6126 | template |
| 6127 | void |
| 6128 | Layout::add_to_gdb_index(bool is_type_unit, |
| 6129 | Sized_relobj<64, false>* object, |
| 6130 | const unsigned char* symbols, |
| 6131 | off_t symbols_size, |
| 6132 | unsigned int shndx, |
| 6133 | unsigned int reloc_shndx, |
| 6134 | unsigned int reloc_type); |
| 6135 | #endif |
| 6136 | |
| 6137 | #ifdef HAVE_TARGET_64_BIG |
| 6138 | template |
| 6139 | void |
| 6140 | Layout::add_to_gdb_index(bool is_type_unit, |
| 6141 | Sized_relobj<64, true>* object, |
| 6142 | const unsigned char* symbols, |
| 6143 | off_t symbols_size, |
| 6144 | unsigned int shndx, |
| 6145 | unsigned int reloc_shndx, |
| 6146 | unsigned int reloc_type); |
| 6147 | #endif |
| 6148 | |
| 6149 | } // End namespace gold. |