| 1 | // dwarf_reader.h -- parse dwarf2/3 debug information for gold -*- C++ -*- |
| 2 | |
| 3 | // Copyright (C) 2007-2015 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 | #ifndef GOLD_DWARF_READER_H |
| 24 | #define GOLD_DWARF_READER_H |
| 25 | |
| 26 | #include <vector> |
| 27 | #include <map> |
| 28 | #include <limits.h> |
| 29 | #include <sys/types.h> |
| 30 | |
| 31 | #include "elfcpp.h" |
| 32 | #include "elfcpp_swap.h" |
| 33 | #include "dwarf.h" |
| 34 | #include "reloc.h" |
| 35 | |
| 36 | namespace gold |
| 37 | { |
| 38 | |
| 39 | class Dwarf_info_reader; |
| 40 | struct LineStateMachine; |
| 41 | |
| 42 | // This class is used to extract the section index and offset of |
| 43 | // the target of a relocation for a given offset within the section. |
| 44 | |
| 45 | class Elf_reloc_mapper |
| 46 | { |
| 47 | public: |
| 48 | Elf_reloc_mapper() |
| 49 | { } |
| 50 | |
| 51 | virtual |
| 52 | ~Elf_reloc_mapper() |
| 53 | { } |
| 54 | |
| 55 | // Initialize the relocation tracker for section RELOC_SHNDX. |
| 56 | bool |
| 57 | initialize(unsigned int reloc_shndx, unsigned int reloc_type) |
| 58 | { return this->do_initialize(reloc_shndx, reloc_type); } |
| 59 | |
| 60 | // Return the next reloc_offset. |
| 61 | off_t |
| 62 | next_offset() |
| 63 | { return this->do_next_offset(); } |
| 64 | |
| 65 | // Advance to the next relocation past OFFSET. |
| 66 | void |
| 67 | advance(off_t offset) |
| 68 | { this->do_advance(offset); } |
| 69 | |
| 70 | // Return the section index and offset within the section of the target |
| 71 | // of the relocation for RELOC_OFFSET in the referring section. |
| 72 | unsigned int |
| 73 | get_reloc_target(off_t reloc_offset, off_t* target_offset) |
| 74 | { return this->do_get_reloc_target(reloc_offset, target_offset); } |
| 75 | |
| 76 | // Checkpoint the current position in the reloc section. |
| 77 | uint64_t |
| 78 | checkpoint() const |
| 79 | { return this->do_checkpoint(); } |
| 80 | |
| 81 | // Reset the current position to the CHECKPOINT. |
| 82 | void |
| 83 | reset(uint64_t checkpoint) |
| 84 | { this->do_reset(checkpoint); } |
| 85 | |
| 86 | protected: |
| 87 | virtual bool |
| 88 | do_initialize(unsigned int, unsigned int) = 0; |
| 89 | |
| 90 | // Return the next reloc_offset. |
| 91 | virtual off_t |
| 92 | do_next_offset() = 0; |
| 93 | |
| 94 | // Advance to the next relocation past OFFSET. |
| 95 | virtual void |
| 96 | do_advance(off_t offset) = 0; |
| 97 | |
| 98 | virtual unsigned int |
| 99 | do_get_reloc_target(off_t reloc_offset, off_t* target_offset) = 0; |
| 100 | |
| 101 | // Checkpoint the current position in the reloc section. |
| 102 | virtual uint64_t |
| 103 | do_checkpoint() const = 0; |
| 104 | |
| 105 | // Reset the current position to the CHECKPOINT. |
| 106 | virtual void |
| 107 | do_reset(uint64_t checkpoint) = 0; |
| 108 | }; |
| 109 | |
| 110 | template<int size, bool big_endian> |
| 111 | class Sized_elf_reloc_mapper : public Elf_reloc_mapper |
| 112 | { |
| 113 | public: |
| 114 | Sized_elf_reloc_mapper(Object* object, const unsigned char* symtab, |
| 115 | off_t symtab_size) |
| 116 | : object_(object), symtab_(symtab), symtab_size_(symtab_size), |
| 117 | reloc_type_(0), track_relocs_() |
| 118 | { } |
| 119 | |
| 120 | protected: |
| 121 | bool |
| 122 | do_initialize(unsigned int reloc_shndx, unsigned int reloc_type); |
| 123 | |
| 124 | // Return the next reloc_offset. |
| 125 | virtual off_t |
| 126 | do_next_offset() |
| 127 | { return this->track_relocs_.next_offset(); } |
| 128 | |
| 129 | // Advance to the next relocation past OFFSET. |
| 130 | virtual void |
| 131 | do_advance(off_t offset) |
| 132 | { this->track_relocs_.advance(offset); } |
| 133 | |
| 134 | unsigned int |
| 135 | do_get_reloc_target(off_t reloc_offset, off_t* target_offset); |
| 136 | |
| 137 | // Checkpoint the current position in the reloc section. |
| 138 | uint64_t |
| 139 | do_checkpoint() const |
| 140 | { return this->track_relocs_.checkpoint(); } |
| 141 | |
| 142 | // Reset the current position to the CHECKPOINT. |
| 143 | void |
| 144 | do_reset(uint64_t checkpoint) |
| 145 | { this->track_relocs_.reset(checkpoint); } |
| 146 | |
| 147 | private: |
| 148 | typedef typename elfcpp::Elf_types<size>::Elf_Addr Address; |
| 149 | |
| 150 | // Return the section index of symbol SYMNDX, and copy its value to *VALUE. |
| 151 | // Set *IS_ORDINARY true if the section index is an ordinary section index. |
| 152 | unsigned int |
| 153 | symbol_section(unsigned int symndx, Address* value, bool* is_ordinary); |
| 154 | |
| 155 | // The object file. |
| 156 | Object* object_; |
| 157 | // The ELF symbol table. |
| 158 | const unsigned char* symtab_; |
| 159 | // The size of the ELF symbol table. |
| 160 | off_t symtab_size_; |
| 161 | // Type of the relocation section (SHT_REL or SHT_RELA). |
| 162 | unsigned int reloc_type_; |
| 163 | // Relocations for the referring section. |
| 164 | Track_relocs<size, big_endian> track_relocs_; |
| 165 | }; |
| 166 | |
| 167 | // This class is used to read the abbreviations table from the |
| 168 | // .debug_abbrev section of the object file. |
| 169 | |
| 170 | class Dwarf_abbrev_table |
| 171 | { |
| 172 | public: |
| 173 | // An attribute list entry. |
| 174 | struct Attribute |
| 175 | { |
| 176 | Attribute(unsigned int a, unsigned int f) |
| 177 | : attr(a), form(f) |
| 178 | { } |
| 179 | unsigned int attr; |
| 180 | unsigned int form; |
| 181 | }; |
| 182 | |
| 183 | // An abbrev code entry. |
| 184 | struct Abbrev_code |
| 185 | { |
| 186 | Abbrev_code(unsigned int t, bool hc) |
| 187 | : tag(t), has_children(hc), has_sibling_attribute(false), attributes() |
| 188 | { |
| 189 | this->attributes.reserve(10); |
| 190 | } |
| 191 | |
| 192 | void |
| 193 | add_attribute(unsigned int attr, unsigned int form) |
| 194 | { |
| 195 | this->attributes.push_back(Attribute(attr, form)); |
| 196 | } |
| 197 | |
| 198 | // The DWARF tag. |
| 199 | unsigned int tag; |
| 200 | // True if the DIE has children. |
| 201 | bool has_children : 1; |
| 202 | // True if the DIE has a sibling attribute. |
| 203 | bool has_sibling_attribute : 1; |
| 204 | // The list of attributes and forms. |
| 205 | std::vector<Attribute> attributes; |
| 206 | }; |
| 207 | |
| 208 | Dwarf_abbrev_table() |
| 209 | : abbrev_shndx_(0), abbrev_offset_(0), buffer_(NULL), buffer_end_(NULL), |
| 210 | owns_buffer_(false), buffer_pos_(NULL), high_abbrev_codes_() |
| 211 | { |
| 212 | memset(this->low_abbrev_codes_, 0, sizeof(this->low_abbrev_codes_)); |
| 213 | } |
| 214 | |
| 215 | ~Dwarf_abbrev_table() |
| 216 | { |
| 217 | if (this->owns_buffer_ && this->buffer_ != NULL) |
| 218 | delete[] this->buffer_; |
| 219 | this->clear_abbrev_codes(); |
| 220 | } |
| 221 | |
| 222 | // Read the abbrev table from an object file. |
| 223 | bool |
| 224 | read_abbrevs(Relobj* object, |
| 225 | unsigned int abbrev_shndx, |
| 226 | off_t abbrev_offset) |
| 227 | { |
| 228 | // If we've already read this abbrev table, return immediately. |
| 229 | if (this->abbrev_shndx_ > 0 |
| 230 | && this->abbrev_shndx_ == abbrev_shndx |
| 231 | && this->abbrev_offset_ == abbrev_offset) |
| 232 | return true; |
| 233 | return this->do_read_abbrevs(object, abbrev_shndx, abbrev_offset); |
| 234 | } |
| 235 | |
| 236 | // Return the abbrev code entry for CODE. This is a fast path for |
| 237 | // abbrev codes that are in the direct lookup table. If not found |
| 238 | // there, we call do_get_abbrev() to do the hard work. |
| 239 | const Abbrev_code* |
| 240 | get_abbrev(unsigned int code) |
| 241 | { |
| 242 | if (code < this->low_abbrev_code_max_ |
| 243 | && this->low_abbrev_codes_[code] != NULL) |
| 244 | return this->low_abbrev_codes_[code]; |
| 245 | return this->do_get_abbrev(code); |
| 246 | } |
| 247 | |
| 248 | private: |
| 249 | // Read the abbrev table from an object file. |
| 250 | bool |
| 251 | do_read_abbrevs(Relobj* object, |
| 252 | unsigned int abbrev_shndx, |
| 253 | off_t abbrev_offset); |
| 254 | |
| 255 | // Lookup the abbrev code entry for CODE. |
| 256 | const Abbrev_code* |
| 257 | do_get_abbrev(unsigned int code); |
| 258 | |
| 259 | // Store an abbrev code entry for CODE. |
| 260 | void |
| 261 | store_abbrev(unsigned int code, const Abbrev_code* entry) |
| 262 | { |
| 263 | if (code < this->low_abbrev_code_max_) |
| 264 | this->low_abbrev_codes_[code] = entry; |
| 265 | else |
| 266 | this->high_abbrev_codes_[code] = entry; |
| 267 | } |
| 268 | |
| 269 | // Clear the abbrev code table and release the memory it uses. |
| 270 | void |
| 271 | clear_abbrev_codes(); |
| 272 | |
| 273 | typedef Unordered_map<unsigned int, const Abbrev_code*> Abbrev_code_table; |
| 274 | |
| 275 | // The section index of the current abbrev table. |
| 276 | unsigned int abbrev_shndx_; |
| 277 | // The offset within the section of the current abbrev table. |
| 278 | off_t abbrev_offset_; |
| 279 | // The buffer containing the .debug_abbrev section. |
| 280 | const unsigned char* buffer_; |
| 281 | const unsigned char* buffer_end_; |
| 282 | // True if this object owns the buffer and needs to delete it. |
| 283 | bool owns_buffer_; |
| 284 | // Pointer to the current position in the buffer. |
| 285 | const unsigned char* buffer_pos_; |
| 286 | // The table of abbrev codes. |
| 287 | // We use a direct-lookup array for low abbrev codes, |
| 288 | // and store the rest in a hash table. |
| 289 | static const unsigned int low_abbrev_code_max_ = 256; |
| 290 | const Abbrev_code* low_abbrev_codes_[low_abbrev_code_max_]; |
| 291 | Abbrev_code_table high_abbrev_codes_; |
| 292 | }; |
| 293 | |
| 294 | // A DWARF range list. The start and end offsets are relative |
| 295 | // to the input section SHNDX. Each range must lie entirely |
| 296 | // within a single section. |
| 297 | |
| 298 | class Dwarf_range_list |
| 299 | { |
| 300 | public: |
| 301 | struct Range |
| 302 | { |
| 303 | Range(unsigned int a_shndx, off_t a_start, off_t a_end) |
| 304 | : shndx(a_shndx), start(a_start), end(a_end) |
| 305 | { } |
| 306 | |
| 307 | unsigned int shndx; |
| 308 | off_t start; |
| 309 | off_t end; |
| 310 | }; |
| 311 | |
| 312 | Dwarf_range_list() |
| 313 | : range_list_() |
| 314 | { } |
| 315 | |
| 316 | void |
| 317 | add(unsigned int shndx, off_t start, off_t end) |
| 318 | { this->range_list_.push_back(Range(shndx, start, end)); } |
| 319 | |
| 320 | size_t |
| 321 | size() const |
| 322 | { return this->range_list_.size(); } |
| 323 | |
| 324 | const Range& |
| 325 | operator[](off_t i) const |
| 326 | { return this->range_list_[i]; } |
| 327 | |
| 328 | private: |
| 329 | std::vector<Range> range_list_; |
| 330 | }; |
| 331 | |
| 332 | // This class is used to read the ranges table from the |
| 333 | // .debug_ranges section of the object file. |
| 334 | |
| 335 | class Dwarf_ranges_table |
| 336 | { |
| 337 | public: |
| 338 | Dwarf_ranges_table(Dwarf_info_reader* dwinfo) |
| 339 | : dwinfo_(dwinfo), ranges_shndx_(0), ranges_buffer_(NULL), |
| 340 | ranges_buffer_end_(NULL), owns_ranges_buffer_(false), |
| 341 | ranges_reloc_mapper_(NULL), reloc_type_(0), output_section_offset_(0) |
| 342 | { } |
| 343 | |
| 344 | ~Dwarf_ranges_table() |
| 345 | { |
| 346 | if (this->owns_ranges_buffer_ && this->ranges_buffer_ != NULL) |
| 347 | delete[] this->ranges_buffer_; |
| 348 | if (this->ranges_reloc_mapper_ != NULL) |
| 349 | delete this->ranges_reloc_mapper_; |
| 350 | } |
| 351 | |
| 352 | // Read the ranges table from an object file. |
| 353 | bool |
| 354 | read_ranges_table(Relobj* object, |
| 355 | const unsigned char* symtab, |
| 356 | off_t symtab_size, |
| 357 | unsigned int ranges_shndx); |
| 358 | |
| 359 | // Read the range table from an object file. |
| 360 | Dwarf_range_list* |
| 361 | read_range_list(Relobj* object, |
| 362 | const unsigned char* symtab, |
| 363 | off_t symtab_size, |
| 364 | unsigned int address_size, |
| 365 | unsigned int ranges_shndx, |
| 366 | off_t ranges_offset); |
| 367 | |
| 368 | // Look for a relocation at offset OFF in the range table, |
| 369 | // and return the section index and offset of the target. |
| 370 | unsigned int |
| 371 | lookup_reloc(off_t off, off_t* target_off); |
| 372 | |
| 373 | private: |
| 374 | // The Dwarf_info_reader, for reading data. |
| 375 | Dwarf_info_reader* dwinfo_; |
| 376 | // The section index of the ranges table. |
| 377 | unsigned int ranges_shndx_; |
| 378 | // The buffer containing the .debug_ranges section. |
| 379 | const unsigned char* ranges_buffer_; |
| 380 | const unsigned char* ranges_buffer_end_; |
| 381 | // True if this object owns the buffer and needs to delete it. |
| 382 | bool owns_ranges_buffer_; |
| 383 | // Relocation mapper for the .debug_ranges section. |
| 384 | Elf_reloc_mapper* ranges_reloc_mapper_; |
| 385 | // Type of the relocation section (SHT_REL or SHT_RELA). |
| 386 | unsigned int reloc_type_; |
| 387 | // For incremental update links, this will hold the offset of the |
| 388 | // input section within the output section. Offsets read from |
| 389 | // relocated data will be relative to the output section, and need |
| 390 | // to be corrected before reading data from the input section. |
| 391 | uint64_t output_section_offset_; |
| 392 | }; |
| 393 | |
| 394 | // This class is used to read the pubnames and pubtypes tables from the |
| 395 | // .debug_pubnames and .debug_pubtypes sections of the object file. |
| 396 | |
| 397 | class Dwarf_pubnames_table |
| 398 | { |
| 399 | public: |
| 400 | Dwarf_pubnames_table(Dwarf_info_reader* dwinfo, bool is_pubtypes) |
| 401 | : dwinfo_(dwinfo), buffer_(NULL), buffer_end_(NULL), owns_buffer_(false), |
| 402 | offset_size_(0), pinfo_(NULL), end_of_table_(NULL), |
| 403 | is_pubtypes_(is_pubtypes), is_gnu_style_(false), |
| 404 | unit_length_(0), cu_offset_(0) |
| 405 | { } |
| 406 | |
| 407 | ~Dwarf_pubnames_table() |
| 408 | { |
| 409 | if (this->owns_buffer_ && this->buffer_ != NULL) |
| 410 | delete[] this->buffer_; |
| 411 | } |
| 412 | |
| 413 | // Read the pubnames section from the object file, using the symbol |
| 414 | // table for relocating it. |
| 415 | bool |
| 416 | read_section(Relobj* object, const unsigned char* symbol_table, |
| 417 | off_t symtab_size); |
| 418 | |
| 419 | // Read the header for the set at OFFSET. |
| 420 | bool |
| 421 | read_header(off_t offset); |
| 422 | |
| 423 | // Return the offset to the cu within the info or types section. |
| 424 | off_t |
| 425 | cu_offset() |
| 426 | { return this->cu_offset_; } |
| 427 | |
| 428 | // Return the size of this subsection of the table. The unit length |
| 429 | // doesn't include the size of its own field. |
| 430 | off_t |
| 431 | subsection_size() |
| 432 | { return this->unit_length_; } |
| 433 | |
| 434 | // Read the next name from the set. If the pubname table is gnu-style, |
| 435 | // FLAG_BYTE is set to the high-byte of a gdb_index version 7 cu_index. |
| 436 | const char* |
| 437 | next_name(uint8_t* flag_byte); |
| 438 | |
| 439 | private: |
| 440 | // The Dwarf_info_reader, for reading data. |
| 441 | Dwarf_info_reader* dwinfo_; |
| 442 | // The buffer containing the .debug_ranges section. |
| 443 | const unsigned char* buffer_; |
| 444 | const unsigned char* buffer_end_; |
| 445 | // True if this object owns the buffer and needs to delete it. |
| 446 | bool owns_buffer_; |
| 447 | // The size of a DWARF offset for the current set. |
| 448 | unsigned int offset_size_; |
| 449 | // The current position within the buffer. |
| 450 | const unsigned char* pinfo_; |
| 451 | // The end of the current pubnames table. |
| 452 | const unsigned char* end_of_table_; |
| 453 | // TRUE if this is a .debug_pubtypes section. |
| 454 | bool is_pubtypes_; |
| 455 | // Gnu-style pubnames table. This style has an extra flag byte between the |
| 456 | // offset and the name, and is used for generating version 7 of gdb-index. |
| 457 | bool is_gnu_style_; |
| 458 | // Fields read from the header. |
| 459 | uint64_t unit_length_; |
| 460 | off_t cu_offset_; |
| 461 | |
| 462 | // Track relocations for this table so we can find the CUs that |
| 463 | // correspond to the subsections. |
| 464 | Elf_reloc_mapper* reloc_mapper_; |
| 465 | // Type of the relocation section (SHT_REL or SHT_RELA). |
| 466 | unsigned int reloc_type_; |
| 467 | }; |
| 468 | |
| 469 | // This class represents a DWARF Debug Info Entry (DIE). |
| 470 | |
| 471 | class Dwarf_die |
| 472 | { |
| 473 | public: |
| 474 | // An attribute value. |
| 475 | struct Attribute_value |
| 476 | { |
| 477 | unsigned int attr; |
| 478 | unsigned int form; |
| 479 | union |
| 480 | { |
| 481 | int64_t intval; |
| 482 | uint64_t uintval; |
| 483 | const char* stringval; |
| 484 | const unsigned char* blockval; |
| 485 | off_t refval; |
| 486 | } val; |
| 487 | union |
| 488 | { |
| 489 | // Section index for reference forms. |
| 490 | unsigned int shndx; |
| 491 | // Block length for block forms. |
| 492 | unsigned int blocklen; |
| 493 | // Attribute offset for DW_FORM_strp. |
| 494 | unsigned int attr_off; |
| 495 | } aux; |
| 496 | }; |
| 497 | |
| 498 | // A list of attribute values. |
| 499 | typedef std::vector<Attribute_value> Attributes; |
| 500 | |
| 501 | Dwarf_die(Dwarf_info_reader* dwinfo, |
| 502 | off_t die_offset, |
| 503 | Dwarf_die* parent); |
| 504 | |
| 505 | // Return the DWARF tag for this DIE. |
| 506 | unsigned int |
| 507 | tag() const |
| 508 | { |
| 509 | if (this->abbrev_code_ == NULL) |
| 510 | return 0; |
| 511 | return this->abbrev_code_->tag; |
| 512 | } |
| 513 | |
| 514 | // Return true if this DIE has children. |
| 515 | bool |
| 516 | has_children() const |
| 517 | { |
| 518 | gold_assert(this->abbrev_code_ != NULL); |
| 519 | return this->abbrev_code_->has_children; |
| 520 | } |
| 521 | |
| 522 | // Return true if this DIE has a sibling attribute. |
| 523 | bool |
| 524 | has_sibling_attribute() const |
| 525 | { |
| 526 | gold_assert(this->abbrev_code_ != NULL); |
| 527 | return this->abbrev_code_->has_sibling_attribute; |
| 528 | } |
| 529 | |
| 530 | // Return the value of attribute ATTR. |
| 531 | const Attribute_value* |
| 532 | attribute(unsigned int attr); |
| 533 | |
| 534 | // Return the value of the DW_AT_name attribute. |
| 535 | const char* |
| 536 | name() |
| 537 | { |
| 538 | if (this->name_ == NULL) |
| 539 | this->set_name(); |
| 540 | return this->name_; |
| 541 | } |
| 542 | |
| 543 | // Return the value of the DW_AT_linkage_name |
| 544 | // or DW_AT_MIPS_linkage_name attribute. |
| 545 | const char* |
| 546 | linkage_name() |
| 547 | { |
| 548 | if (this->linkage_name_ == NULL) |
| 549 | this->set_linkage_name(); |
| 550 | return this->linkage_name_; |
| 551 | } |
| 552 | |
| 553 | // Return the value of the DW_AT_specification attribute. |
| 554 | off_t |
| 555 | specification() |
| 556 | { |
| 557 | if (!this->attributes_read_) |
| 558 | this->read_attributes(); |
| 559 | return this->specification_; |
| 560 | } |
| 561 | |
| 562 | // Return the value of the DW_AT_abstract_origin attribute. |
| 563 | off_t |
| 564 | abstract_origin() |
| 565 | { |
| 566 | if (!this->attributes_read_) |
| 567 | this->read_attributes(); |
| 568 | return this->abstract_origin_; |
| 569 | } |
| 570 | |
| 571 | // Return the value of attribute ATTR as a string. |
| 572 | const char* |
| 573 | string_attribute(unsigned int attr); |
| 574 | |
| 575 | // Return the value of attribute ATTR as an integer. |
| 576 | int64_t |
| 577 | int_attribute(unsigned int attr); |
| 578 | |
| 579 | // Return the value of attribute ATTR as an unsigned integer. |
| 580 | uint64_t |
| 581 | uint_attribute(unsigned int attr); |
| 582 | |
| 583 | // Return the value of attribute ATTR as a reference. |
| 584 | off_t |
| 585 | ref_attribute(unsigned int attr, unsigned int* shndx); |
| 586 | |
| 587 | // Return the value of attribute ATTR as a address. |
| 588 | off_t |
| 589 | address_attribute(unsigned int attr, unsigned int* shndx); |
| 590 | |
| 591 | // Return the value of attribute ATTR as a flag. |
| 592 | bool |
| 593 | flag_attribute(unsigned int attr) |
| 594 | { return this->int_attribute(attr) != 0; } |
| 595 | |
| 596 | // Return true if this DIE is a declaration. |
| 597 | bool |
| 598 | is_declaration() |
| 599 | { return this->flag_attribute(elfcpp::DW_AT_declaration); } |
| 600 | |
| 601 | // Return the parent of this DIE. |
| 602 | Dwarf_die* |
| 603 | parent() const |
| 604 | { return this->parent_; } |
| 605 | |
| 606 | // Return the offset of this DIE. |
| 607 | off_t |
| 608 | offset() const |
| 609 | { return this->die_offset_; } |
| 610 | |
| 611 | // Return the offset of this DIE's first child. |
| 612 | off_t |
| 613 | child_offset(); |
| 614 | |
| 615 | // Set the offset of this DIE's next sibling. |
| 616 | void |
| 617 | set_sibling_offset(off_t sibling_offset) |
| 618 | { this->sibling_offset_ = sibling_offset; } |
| 619 | |
| 620 | // Return the offset of this DIE's next sibling. |
| 621 | off_t |
| 622 | sibling_offset(); |
| 623 | |
| 624 | private: |
| 625 | typedef Dwarf_abbrev_table::Abbrev_code Abbrev_code; |
| 626 | |
| 627 | // Read all the attributes of the DIE. |
| 628 | bool |
| 629 | read_attributes(); |
| 630 | |
| 631 | // Set the name of the DIE if present. |
| 632 | void |
| 633 | set_name(); |
| 634 | |
| 635 | // Set the linkage name if present. |
| 636 | void |
| 637 | set_linkage_name(); |
| 638 | |
| 639 | // Skip all the attributes of the DIE and return the offset |
| 640 | // of the next DIE. |
| 641 | off_t |
| 642 | skip_attributes(); |
| 643 | |
| 644 | // The Dwarf_info_reader, for reading attributes. |
| 645 | Dwarf_info_reader* dwinfo_; |
| 646 | // The parent of this DIE. |
| 647 | Dwarf_die* parent_; |
| 648 | // Offset of this DIE within its compilation unit. |
| 649 | off_t die_offset_; |
| 650 | // Offset of the first attribute, relative to the beginning of the DIE. |
| 651 | off_t attr_offset_; |
| 652 | // Offset of the first child, relative to the compilation unit. |
| 653 | off_t child_offset_; |
| 654 | // Offset of the next sibling, relative to the compilation unit. |
| 655 | off_t sibling_offset_; |
| 656 | // The abbreviation table entry. |
| 657 | const Abbrev_code* abbrev_code_; |
| 658 | // The list of attributes. |
| 659 | Attributes attributes_; |
| 660 | // True if the attributes have been read. |
| 661 | bool attributes_read_; |
| 662 | // The following fields hold common attributes to avoid a linear |
| 663 | // search through the attribute list. |
| 664 | // The DIE name (DW_AT_name). |
| 665 | const char* name_; |
| 666 | // Offset of the name in the string table (for DW_FORM_strp). |
| 667 | off_t name_off_; |
| 668 | // The linkage name (DW_AT_linkage_name or DW_AT_MIPS_linkage_name). |
| 669 | const char* linkage_name_; |
| 670 | // Offset of the linkage name in the string table (for DW_FORM_strp). |
| 671 | off_t linkage_name_off_; |
| 672 | // Section index of the string table (for DW_FORM_strp). |
| 673 | unsigned int string_shndx_; |
| 674 | // The value of a DW_AT_specification attribute. |
| 675 | off_t specification_; |
| 676 | // The value of a DW_AT_abstract_origin attribute. |
| 677 | off_t abstract_origin_; |
| 678 | }; |
| 679 | |
| 680 | // This class is used to read the debug info from the .debug_info |
| 681 | // or .debug_types sections. This is a base class that implements |
| 682 | // the generic parsing of the compilation unit header and DIE |
| 683 | // structure. The parse() method parses the entire section, and |
| 684 | // calls the various visit_xxx() methods for each header. Clients |
| 685 | // should derive a new class from this one and implement the |
| 686 | // visit_compilation_unit() and visit_type_unit() functions. |
| 687 | |
| 688 | class Dwarf_info_reader |
| 689 | { |
| 690 | public: |
| 691 | Dwarf_info_reader(bool is_type_unit, |
| 692 | Relobj* object, |
| 693 | const unsigned char* symtab, |
| 694 | off_t symtab_size, |
| 695 | unsigned int shndx, |
| 696 | unsigned int reloc_shndx, |
| 697 | unsigned int reloc_type) |
| 698 | : is_type_unit_(is_type_unit), object_(object), symtab_(symtab), |
| 699 | symtab_size_(symtab_size), shndx_(shndx), reloc_shndx_(reloc_shndx), |
| 700 | reloc_type_(reloc_type), abbrev_shndx_(0), string_shndx_(0), |
| 701 | buffer_(NULL), buffer_end_(NULL), cu_offset_(0), cu_length_(0), |
| 702 | offset_size_(0), address_size_(0), cu_version_(0), |
| 703 | abbrev_table_(), ranges_table_(this), |
| 704 | reloc_mapper_(NULL), string_buffer_(NULL), string_buffer_end_(NULL), |
| 705 | owns_string_buffer_(false), string_output_section_offset_(0) |
| 706 | { } |
| 707 | |
| 708 | virtual |
| 709 | ~Dwarf_info_reader() |
| 710 | { |
| 711 | if (this->reloc_mapper_ != NULL) |
| 712 | delete this->reloc_mapper_; |
| 713 | if (this->owns_string_buffer_ && this->string_buffer_ != NULL) |
| 714 | delete[] this->string_buffer_; |
| 715 | } |
| 716 | |
| 717 | // Begin parsing the debug info. This calls visit_compilation_unit() |
| 718 | // or visit_type_unit() for each compilation or type unit found in the |
| 719 | // section, and visit_die() for each top-level DIE. |
| 720 | void |
| 721 | parse(); |
| 722 | |
| 723 | // Return the abbrev code entry for a CODE. |
| 724 | const Dwarf_abbrev_table::Abbrev_code* |
| 725 | get_abbrev(unsigned int code) |
| 726 | { return this->abbrev_table_.get_abbrev(code); } |
| 727 | |
| 728 | // Return a pointer to the DWARF info buffer at OFFSET. |
| 729 | const unsigned char* |
| 730 | buffer_at_offset(off_t offset) const |
| 731 | { |
| 732 | const unsigned char* p = this->buffer_ + this->cu_offset_ + offset; |
| 733 | if (this->check_buffer(p + 1)) |
| 734 | return p; |
| 735 | return NULL; |
| 736 | } |
| 737 | |
| 738 | // Read a possibly unaligned integer of SIZE. |
| 739 | template <int valsize> |
| 740 | inline typename elfcpp::Valtype_base<valsize>::Valtype |
| 741 | read_from_pointer(const unsigned char* source); |
| 742 | |
| 743 | // Read a possibly unaligned integer of SIZE. Update SOURCE after read. |
| 744 | template <int valsize> |
| 745 | inline typename elfcpp::Valtype_base<valsize>::Valtype |
| 746 | read_from_pointer(const unsigned char** source); |
| 747 | |
| 748 | // Look for a relocation at offset ATTR_OFF in the dwarf info, |
| 749 | // and return the section index and offset of the target. |
| 750 | unsigned int |
| 751 | lookup_reloc(off_t attr_off, off_t* target_off); |
| 752 | |
| 753 | // Return a string from the DWARF string table. |
| 754 | const char* |
| 755 | get_string(off_t str_off, unsigned int string_shndx); |
| 756 | |
| 757 | // Return the size of a DWARF offset. |
| 758 | unsigned int |
| 759 | offset_size() const |
| 760 | { return this->offset_size_; } |
| 761 | |
| 762 | // Return the size of an address. |
| 763 | unsigned int |
| 764 | address_size() const |
| 765 | { return this->address_size_; } |
| 766 | |
| 767 | // Set the section index of the .debug_abbrev section. |
| 768 | // We use this if there are no relocations for the .debug_info section. |
| 769 | // If not set, the code parse() routine will search for the section by name. |
| 770 | void |
| 771 | set_abbrev_shndx(unsigned int abbrev_shndx) |
| 772 | { this->abbrev_shndx_ = abbrev_shndx; } |
| 773 | |
| 774 | // Return a pointer to the object file's ELF symbol table. |
| 775 | const unsigned char* |
| 776 | symtab() const |
| 777 | { return this->symtab_; } |
| 778 | |
| 779 | // Return the size of the object file's ELF symbol table. |
| 780 | off_t |
| 781 | symtab_size() const |
| 782 | { return this->symtab_size_; } |
| 783 | |
| 784 | // Return the offset of the current compilation unit. |
| 785 | off_t |
| 786 | cu_offset() const |
| 787 | { return this->cu_offset_; } |
| 788 | |
| 789 | protected: |
| 790 | // Begin parsing the debug info. This calls visit_compilation_unit() |
| 791 | // or visit_type_unit() for each compilation or type unit found in the |
| 792 | // section, and visit_die() for each top-level DIE. |
| 793 | template<bool big_endian> |
| 794 | void |
| 795 | do_parse(); |
| 796 | |
| 797 | // The following methods are hooks that are meant to be implemented |
| 798 | // by a derived class. A default, do-nothing, implementation of |
| 799 | // each is provided for this base class. |
| 800 | |
| 801 | // Visit a compilation unit. |
| 802 | virtual void |
| 803 | visit_compilation_unit(off_t cu_offset, off_t cu_length, Dwarf_die* root_die); |
| 804 | |
| 805 | // Visit a type unit. |
| 806 | virtual void |
| 807 | visit_type_unit(off_t tu_offset, off_t tu_length, off_t type_offset, |
| 808 | uint64_t signature, Dwarf_die* root_die); |
| 809 | |
| 810 | // Read the range table. |
| 811 | Dwarf_range_list* |
| 812 | read_range_list(unsigned int ranges_shndx, off_t ranges_offset) |
| 813 | { |
| 814 | return this->ranges_table_.read_range_list(this->object_, |
| 815 | this->symtab_, |
| 816 | this->symtab_size_, |
| 817 | this->address_size_, |
| 818 | ranges_shndx, |
| 819 | ranges_offset); |
| 820 | } |
| 821 | |
| 822 | // Return the object. |
| 823 | Relobj* |
| 824 | object() const |
| 825 | { return this->object_; } |
| 826 | |
| 827 | // Checkpoint the relocation tracker. |
| 828 | uint64_t |
| 829 | get_reloc_checkpoint() const |
| 830 | { return this->reloc_mapper_->checkpoint(); } |
| 831 | |
| 832 | // Reset the relocation tracker to the CHECKPOINT. |
| 833 | void |
| 834 | reset_relocs(uint64_t checkpoint) |
| 835 | { this->reloc_mapper_->reset(checkpoint); } |
| 836 | |
| 837 | private: |
| 838 | // Print a warning about a corrupt debug section. |
| 839 | void |
| 840 | warn_corrupt_debug_section() const; |
| 841 | |
| 842 | // Check that P is within the bounds of the current section. |
| 843 | bool |
| 844 | check_buffer(const unsigned char* p) const |
| 845 | { |
| 846 | if (p > this->buffer_ + this->cu_offset_ + this->cu_length_) |
| 847 | { |
| 848 | this->warn_corrupt_debug_section(); |
| 849 | return false; |
| 850 | } |
| 851 | return true; |
| 852 | } |
| 853 | |
| 854 | // Read the DWARF string table. |
| 855 | bool |
| 856 | read_string_table(unsigned int string_shndx) |
| 857 | { |
| 858 | // If we've already read this string table, return immediately. |
| 859 | if (this->string_shndx_ > 0 && this->string_shndx_ == string_shndx) |
| 860 | return true; |
| 861 | if (string_shndx == 0 && this->string_shndx_ > 0) |
| 862 | return true; |
| 863 | return this->do_read_string_table(string_shndx); |
| 864 | } |
| 865 | |
| 866 | bool |
| 867 | do_read_string_table(unsigned int string_shndx); |
| 868 | |
| 869 | // True if this is a type unit; false for a compilation unit. |
| 870 | bool is_type_unit_; |
| 871 | // The object containing the .debug_info or .debug_types input section. |
| 872 | Relobj* object_; |
| 873 | // The ELF symbol table. |
| 874 | const unsigned char* symtab_; |
| 875 | // The size of the ELF symbol table. |
| 876 | off_t symtab_size_; |
| 877 | // Index of the .debug_info or .debug_types section. |
| 878 | unsigned int shndx_; |
| 879 | // Index of the relocation section. |
| 880 | unsigned int reloc_shndx_; |
| 881 | // Type of the relocation section (SHT_REL or SHT_RELA). |
| 882 | unsigned int reloc_type_; |
| 883 | // Index of the .debug_abbrev section (0 if not known). |
| 884 | unsigned int abbrev_shndx_; |
| 885 | // Index of the .debug_str section. |
| 886 | unsigned int string_shndx_; |
| 887 | // The buffer for the debug info. |
| 888 | const unsigned char* buffer_; |
| 889 | const unsigned char* buffer_end_; |
| 890 | // Offset of the current compilation unit. |
| 891 | off_t cu_offset_; |
| 892 | // Length of the current compilation unit. |
| 893 | off_t cu_length_; |
| 894 | // Size of a DWARF offset for the current compilation unit. |
| 895 | unsigned int offset_size_; |
| 896 | // Size of an address for the target architecture. |
| 897 | unsigned int address_size_; |
| 898 | // Compilation unit version number. |
| 899 | unsigned int cu_version_; |
| 900 | // Abbreviations table for current compilation unit. |
| 901 | Dwarf_abbrev_table abbrev_table_; |
| 902 | // Ranges table for the current compilation unit. |
| 903 | Dwarf_ranges_table ranges_table_; |
| 904 | // Relocation mapper for the section. |
| 905 | Elf_reloc_mapper* reloc_mapper_; |
| 906 | // The buffer for the debug string table. |
| 907 | const char* string_buffer_; |
| 908 | const char* string_buffer_end_; |
| 909 | // True if this object owns the buffer and needs to delete it. |
| 910 | bool owns_string_buffer_; |
| 911 | // For incremental update links, this will hold the offset of the |
| 912 | // input .debug_str section within the output section. Offsets read |
| 913 | // from relocated data will be relative to the output section, and need |
| 914 | // to be corrected before reading data from the input section. |
| 915 | uint64_t string_output_section_offset_; |
| 916 | }; |
| 917 | |
| 918 | // We can't do better than to keep the offsets in a sorted vector. |
| 919 | // Here, offset is the key, and file_num/line_num is the value. |
| 920 | struct Offset_to_lineno_entry |
| 921 | { |
| 922 | off_t offset; |
| 923 | int header_num; // which file-list to use (i.e. which .o file are we in) |
| 924 | // A pointer into files_. |
| 925 | unsigned int file_num : sizeof(int) * CHAR_BIT - 1; |
| 926 | // True if this was the last entry for the current offset, meaning |
| 927 | // it's the line that actually applies. |
| 928 | unsigned int last_line_for_offset : 1; |
| 929 | // The line number in the source file. -1 to indicate end-of-function. |
| 930 | int line_num; |
| 931 | |
| 932 | // This sorts by offsets first, and then puts the correct line to |
| 933 | // report for a given offset at the beginning of the run of equal |
| 934 | // offsets (so that asking for 1 line gives the best answer). This |
| 935 | // is not a total ordering. |
| 936 | bool operator<(const Offset_to_lineno_entry& that) const |
| 937 | { |
| 938 | if (this->offset != that.offset) |
| 939 | return this->offset < that.offset; |
| 940 | // Note the '>' which makes this sort 'true' first. |
| 941 | return this->last_line_for_offset > that.last_line_for_offset; |
| 942 | } |
| 943 | }; |
| 944 | |
| 945 | // This class is used to read the line information from the debugging |
| 946 | // section of an object file. |
| 947 | |
| 948 | class Dwarf_line_info |
| 949 | { |
| 950 | public: |
| 951 | Dwarf_line_info() |
| 952 | { } |
| 953 | |
| 954 | virtual |
| 955 | ~Dwarf_line_info() |
| 956 | { } |
| 957 | |
| 958 | // Given a section number and an offset, returns the associated |
| 959 | // file and line-number, as a string: "file:lineno". If unable |
| 960 | // to do the mapping, returns the empty string. You must call |
| 961 | // read_line_mappings() before calling this function. If |
| 962 | // 'other_lines' is non-NULL, fills that in with other line |
| 963 | // numbers assigned to the same offset. |
| 964 | std::string |
| 965 | addr2line(unsigned int shndx, off_t offset, |
| 966 | std::vector<std::string>* other_lines) |
| 967 | { return this->do_addr2line(shndx, offset, other_lines); } |
| 968 | |
| 969 | // A helper function for a single addr2line lookup. It also keeps a |
| 970 | // cache of the last CACHE_SIZE Dwarf_line_info objects it created; |
| 971 | // set to 0 not to cache at all. The larger CACHE_SIZE is, the more |
| 972 | // chance this routine won't have to re-create a Dwarf_line_info |
| 973 | // object for its addr2line computation; such creations are slow. |
| 974 | // NOTE: Not thread-safe, so only call from one thread at a time. |
| 975 | static std::string |
| 976 | one_addr2line(Object* object, unsigned int shndx, off_t offset, |
| 977 | size_t cache_size, std::vector<std::string>* other_lines); |
| 978 | |
| 979 | // This reclaims all the memory that one_addr2line may have cached. |
| 980 | // Use this when you know you will not be calling one_addr2line again. |
| 981 | static void |
| 982 | clear_addr2line_cache(); |
| 983 | |
| 984 | private: |
| 985 | virtual std::string |
| 986 | do_addr2line(unsigned int shndx, off_t offset, |
| 987 | std::vector<std::string>* other_lines) = 0; |
| 988 | }; |
| 989 | |
| 990 | template<int size, bool big_endian> |
| 991 | class Sized_dwarf_line_info : public Dwarf_line_info |
| 992 | { |
| 993 | public: |
| 994 | // Initializes a .debug_line reader for a given object file. |
| 995 | // If SHNDX is specified and non-negative, only read the debug |
| 996 | // information that pertains to the specified section. |
| 997 | Sized_dwarf_line_info(Object* object, unsigned int read_shndx = -1U); |
| 998 | |
| 999 | virtual |
| 1000 | ~Sized_dwarf_line_info() |
| 1001 | { |
| 1002 | if (this->buffer_start_ != NULL) |
| 1003 | delete[] this->buffer_start_; |
| 1004 | } |
| 1005 | |
| 1006 | private: |
| 1007 | std::string |
| 1008 | do_addr2line(unsigned int shndx, off_t offset, |
| 1009 | std::vector<std::string>* other_lines); |
| 1010 | |
| 1011 | // Formats a file and line number to a string like "dirname/filename:lineno". |
| 1012 | std::string |
| 1013 | format_file_lineno(const Offset_to_lineno_entry& lineno) const; |
| 1014 | |
| 1015 | // Start processing line info, and populates the offset_map_. |
| 1016 | // If SHNDX is non-negative, only store debug information that |
| 1017 | // pertains to the specified section. |
| 1018 | void |
| 1019 | read_line_mappings(unsigned int shndx); |
| 1020 | |
| 1021 | // Reads the relocation section associated with .debug_line and |
| 1022 | // stores relocation information in reloc_map_. |
| 1023 | void |
| 1024 | read_relocs(); |
| 1025 | |
| 1026 | // Reads the DWARF2/3 header for this line info. Each takes as input |
| 1027 | // a starting buffer position, and returns the ending position. |
| 1028 | const unsigned char* |
| 1029 | read_header_prolog(const unsigned char* lineptr); |
| 1030 | |
| 1031 | const unsigned char* |
| 1032 | read_header_tables(const unsigned char* lineptr); |
| 1033 | |
| 1034 | // Reads the DWARF2/3 line information. If shndx is non-negative, |
| 1035 | // discard all line information that doesn't pertain to the given |
| 1036 | // section. |
| 1037 | const unsigned char* |
| 1038 | read_lines(const unsigned char* lineptr, unsigned int shndx); |
| 1039 | |
| 1040 | // Process a single line info opcode at START using the state |
| 1041 | // machine at LSM. Return true if we should define a line using the |
| 1042 | // current state of the line state machine. Place the length of the |
| 1043 | // opcode in LEN. |
| 1044 | bool |
| 1045 | process_one_opcode(const unsigned char* start, |
| 1046 | struct LineStateMachine* lsm, size_t* len); |
| 1047 | |
| 1048 | // Some parts of processing differ depending on whether the input |
| 1049 | // was a .o file or not. |
| 1050 | bool input_is_relobj(); |
| 1051 | |
| 1052 | // If we saw anything amiss while parsing, we set this to false. |
| 1053 | // Then addr2line will always fail (rather than return possibly- |
| 1054 | // corrupt data). |
| 1055 | bool data_valid_; |
| 1056 | |
| 1057 | // A DWARF2/3 line info header. This is not the same size as in the |
| 1058 | // actual file, as the one in the file may have a 32 bit or 64 bit |
| 1059 | // lengths. |
| 1060 | |
| 1061 | struct Dwarf_line_infoHeader |
| 1062 | { |
| 1063 | off_t total_length; |
| 1064 | int version; |
| 1065 | off_t prologue_length; |
| 1066 | int min_insn_length; // insn stands for instructin |
| 1067 | bool default_is_stmt; // stmt stands for statement |
| 1068 | signed char line_base; |
| 1069 | int line_range; |
| 1070 | unsigned char opcode_base; |
| 1071 | std::vector<unsigned char> std_opcode_lengths; |
| 1072 | int offset_size; |
| 1073 | } header_; |
| 1074 | |
| 1075 | // buffer is the buffer for our line info, starting at exactly where |
| 1076 | // the line info to read is. |
| 1077 | const unsigned char* buffer_; |
| 1078 | const unsigned char* buffer_end_; |
| 1079 | // If the buffer was allocated temporarily, and therefore must be |
| 1080 | // deallocated in the dtor, this contains a pointer to the start |
| 1081 | // of the buffer. |
| 1082 | const unsigned char* buffer_start_; |
| 1083 | |
| 1084 | // This has relocations that point into buffer. |
| 1085 | Sized_elf_reloc_mapper<size, big_endian>* reloc_mapper_; |
| 1086 | // The type of the reloc section in track_relocs_--SHT_REL or SHT_RELA. |
| 1087 | unsigned int track_relocs_type_; |
| 1088 | |
| 1089 | // This is used to figure out what section to apply a relocation to. |
| 1090 | const unsigned char* symtab_buffer_; |
| 1091 | section_size_type symtab_buffer_size_; |
| 1092 | |
| 1093 | // Holds the directories and files as we see them. We have an array |
| 1094 | // of directory-lists, one for each .o file we're reading (usually |
| 1095 | // there will just be one, but there may be more if input is a .so). |
| 1096 | std::vector<std::vector<std::string> > directories_; |
| 1097 | // The first part is an index into directories_, the second the filename. |
| 1098 | std::vector<std::vector< std::pair<int, std::string> > > files_; |
| 1099 | |
| 1100 | // An index into the current directories_ and files_ vectors. |
| 1101 | int current_header_index_; |
| 1102 | |
| 1103 | // A sorted map from offset of the relocation target to the shndx |
| 1104 | // and addend for the relocation. |
| 1105 | typedef std::map<off_t, std::pair<unsigned int, off_t> > |
| 1106 | Reloc_map; |
| 1107 | Reloc_map reloc_map_; |
| 1108 | |
| 1109 | // We have a vector of offset->lineno entries for every input section. |
| 1110 | typedef Unordered_map<unsigned int, std::vector<Offset_to_lineno_entry> > |
| 1111 | Lineno_map; |
| 1112 | |
| 1113 | Lineno_map line_number_map_; |
| 1114 | }; |
| 1115 | |
| 1116 | } // End namespace gold. |
| 1117 | |
| 1118 | #endif // !defined(GOLD_DWARF_READER_H) |