| 1 | // i386.cc -- i386 target support for gold. |
| 2 | |
| 3 | #include "gold.h" |
| 4 | |
| 5 | #include <cstring> |
| 6 | |
| 7 | #include "elfcpp.h" |
| 8 | #include "reloc.h" |
| 9 | #include "i386.h" |
| 10 | #include "object.h" |
| 11 | #include "symtab.h" |
| 12 | #include "layout.h" |
| 13 | #include "output.h" |
| 14 | #include "target.h" |
| 15 | #include "target-reloc.h" |
| 16 | #include "target-select.h" |
| 17 | |
| 18 | namespace |
| 19 | { |
| 20 | |
| 21 | using namespace gold; |
| 22 | |
| 23 | class Output_data_plt_i386; |
| 24 | |
| 25 | // The i386 target class. |
| 26 | |
| 27 | class Target_i386 : public Sized_target<32, false> |
| 28 | { |
| 29 | public: |
| 30 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| 31 | |
| 32 | Target_i386() |
| 33 | : Sized_target<32, false>(&i386_info), |
| 34 | got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL), |
| 35 | copy_relocs_(NULL), dynbss_(NULL) |
| 36 | { } |
| 37 | |
| 38 | // Scan the relocations to look for symbol adjustments. |
| 39 | void |
| 40 | scan_relocs(const General_options& options, |
| 41 | Symbol_table* symtab, |
| 42 | Layout* layout, |
| 43 | Sized_relobj<32, false>* object, |
| 44 | unsigned int data_shndx, |
| 45 | unsigned int sh_type, |
| 46 | const unsigned char* prelocs, |
| 47 | size_t reloc_count, |
| 48 | size_t local_symbol_count, |
| 49 | const unsigned char* plocal_symbols, |
| 50 | Symbol** global_symbols); |
| 51 | |
| 52 | // Finalize the sections. |
| 53 | void |
| 54 | do_finalize_sections(const General_options*, Layout*); |
| 55 | |
| 56 | // Relocate a section. |
| 57 | void |
| 58 | relocate_section(const Relocate_info<32, false>*, |
| 59 | unsigned int sh_type, |
| 60 | const unsigned char* prelocs, |
| 61 | size_t reloc_count, |
| 62 | unsigned char* view, |
| 63 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 64 | off_t view_size); |
| 65 | |
| 66 | private: |
| 67 | // The class which scans relocations. |
| 68 | struct Scan |
| 69 | { |
| 70 | inline void |
| 71 | local(const General_options& options, Symbol_table* symtab, |
| 72 | Layout* layout, Target_i386* target, |
| 73 | Sized_relobj<32, false>* object, |
| 74 | unsigned int data_shndx, |
| 75 | const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| 76 | const elfcpp::Sym<32, false>& lsym); |
| 77 | |
| 78 | inline void |
| 79 | global(const General_options& options, Symbol_table* symtab, |
| 80 | Layout* layout, Target_i386* target, |
| 81 | Sized_relobj<32, false>* object, |
| 82 | unsigned int data_shndx, |
| 83 | const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| 84 | Symbol* gsym); |
| 85 | }; |
| 86 | |
| 87 | // The class which implements relocation. |
| 88 | class Relocate |
| 89 | { |
| 90 | public: |
| 91 | Relocate() |
| 92 | : skip_call_tls_get_addr_(false) |
| 93 | { } |
| 94 | |
| 95 | ~Relocate() |
| 96 | { |
| 97 | if (this->skip_call_tls_get_addr_) |
| 98 | { |
| 99 | // FIXME: This needs to specify the location somehow. |
| 100 | fprintf(stderr, _("%s: missing expected TLS relocation\n"), |
| 101 | program_name); |
| 102 | gold_exit(false); |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | // Do a relocation. Return false if the caller should not issue |
| 107 | // any warnings about this relocation. |
| 108 | inline bool |
| 109 | relocate(const Relocate_info<32, false>*, Target_i386*, size_t relnum, |
| 110 | const elfcpp::Rel<32, false>&, |
| 111 | unsigned int r_type, const Sized_symbol<32>*, |
| 112 | elfcpp::Elf_types<32>::Elf_Addr, |
| 113 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| 114 | off_t); |
| 115 | |
| 116 | private: |
| 117 | // Do a TLS relocation. |
| 118 | inline void |
| 119 | relocate_tls(const Relocate_info<32, false>*, size_t relnum, |
| 120 | const elfcpp::Rel<32, false>&, |
| 121 | unsigned int r_type, const Sized_symbol<32>*, |
| 122 | elfcpp::Elf_types<32>::Elf_Addr, |
| 123 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t); |
| 124 | |
| 125 | // Do a TLS Initial-Exec to Local-Exec transition. |
| 126 | static inline void |
| 127 | tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 128 | Output_segment* tls_segment, |
| 129 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 130 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 131 | unsigned char* view, |
| 132 | off_t view_size); |
| 133 | |
| 134 | // Do a TLS Global-Dynamic to Local-Exec transition. |
| 135 | inline void |
| 136 | tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 137 | Output_segment* tls_segment, |
| 138 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 139 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 140 | unsigned char* view, |
| 141 | off_t view_size); |
| 142 | |
| 143 | // Check the range for a TLS relocation. |
| 144 | static inline void |
| 145 | check_range(const Relocate_info<32, false>*, size_t relnum, |
| 146 | const elfcpp::Rel<32, false>&, off_t, off_t); |
| 147 | |
| 148 | // Check the validity of a TLS relocation. This is like assert. |
| 149 | static inline void |
| 150 | check_tls(const Relocate_info<32, false>*, size_t relnum, |
| 151 | const elfcpp::Rel<32, false>&, bool); |
| 152 | |
| 153 | // This is set if we should skip the next reloc, which should be a |
| 154 | // PLT32 reloc against ___tls_get_addr. |
| 155 | bool skip_call_tls_get_addr_; |
| 156 | }; |
| 157 | |
| 158 | // Adjust TLS relocation type based on the options and whether this |
| 159 | // is a local symbol. |
| 160 | static unsigned int |
| 161 | optimize_tls_reloc(const General_options*, bool is_final, int r_type); |
| 162 | |
| 163 | // Get the GOT section, creating it if necessary. |
| 164 | Output_data_got<32, false>* |
| 165 | got_section(const General_options*, Symbol_table*, Layout*); |
| 166 | |
| 167 | // Create a PLT entry for a global symbol. |
| 168 | void |
| 169 | make_plt_entry(const General_options* options, Symbol_table*, |
| 170 | Layout*, Symbol*); |
| 171 | |
| 172 | // Get the PLT section. |
| 173 | Output_data_plt_i386* |
| 174 | plt_section() const |
| 175 | { |
| 176 | gold_assert(this->plt_ != NULL); |
| 177 | return this->plt_; |
| 178 | } |
| 179 | |
| 180 | // Get the dynamic reloc section, creating it if necessary. |
| 181 | Reloc_section* |
| 182 | rel_dyn_section(Layout*); |
| 183 | |
| 184 | // Copy a relocation against a global symbol. |
| 185 | void |
| 186 | copy_reloc(const General_options*, Symbol_table*, Layout*, |
| 187 | Sized_relobj<32, false>*, unsigned int, |
| 188 | Symbol*, const elfcpp::Rel<32, false>&); |
| 189 | |
| 190 | // Information about this specific target which we pass to the |
| 191 | // general Target structure. |
| 192 | static const Target::Target_info i386_info; |
| 193 | |
| 194 | // The GOT section. |
| 195 | Output_data_got<32, false>* got_; |
| 196 | // The PLT section. |
| 197 | Output_data_plt_i386* plt_; |
| 198 | // The GOT PLT section. |
| 199 | Output_data_space* got_plt_; |
| 200 | // The dynamic reloc section. |
| 201 | Reloc_section* rel_dyn_; |
| 202 | // Relocs saved to avoid a COPY reloc. |
| 203 | Copy_relocs<32, false>* copy_relocs_; |
| 204 | // Space for variables copied with a COPY reloc. |
| 205 | Output_data_space* dynbss_; |
| 206 | }; |
| 207 | |
| 208 | const Target::Target_info Target_i386::i386_info = |
| 209 | { |
| 210 | 32, // size |
| 211 | false, // is_big_endian |
| 212 | elfcpp::EM_386, // machine_code |
| 213 | false, // has_make_symbol |
| 214 | false, // has_resolve |
| 215 | "/usr/lib/libc.so.1", // dynamic_linker |
| 216 | 0x08048000, // text_segment_address |
| 217 | 0x1000, // abi_pagesize |
| 218 | 0x1000 // common_pagesize |
| 219 | }; |
| 220 | |
| 221 | // Get the GOT section, creating it if necessary. |
| 222 | |
| 223 | Output_data_got<32, false>* |
| 224 | Target_i386::got_section(const General_options* options, Symbol_table* symtab, |
| 225 | Layout* layout) |
| 226 | { |
| 227 | if (this->got_ == NULL) |
| 228 | { |
| 229 | gold_assert(options != NULL && symtab != NULL && layout != NULL); |
| 230 | |
| 231 | this->got_ = new Output_data_got<32, false>(options); |
| 232 | |
| 233 | layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| 234 | elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, |
| 235 | this->got_); |
| 236 | |
| 237 | // The old GNU linker creates a .got.plt section. We just |
| 238 | // create another set of data in the .got section. Note that we |
| 239 | // always create a PLT if we create a GOT, although the PLT |
| 240 | // might be empty. |
| 241 | this->got_plt_ = new Output_data_space(4); |
| 242 | layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| 243 | elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE, |
| 244 | this->got_plt_); |
| 245 | |
| 246 | // The first three entries are reserved. |
| 247 | this->got_plt_->set_space_size(3 * 4); |
| 248 | |
| 249 | // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| 250 | symtab->define_in_output_data(this, "_GLOBAL_OFFSET_TABLE_", NULL, |
| 251 | this->got_plt_, |
| 252 | 0, 0, elfcpp::STT_OBJECT, |
| 253 | elfcpp::STB_LOCAL, |
| 254 | elfcpp::STV_HIDDEN, 0, |
| 255 | false, false); |
| 256 | } |
| 257 | |
| 258 | return this->got_; |
| 259 | } |
| 260 | |
| 261 | // Get the dynamic reloc section, creating it if necessary. |
| 262 | |
| 263 | Target_i386::Reloc_section* |
| 264 | Target_i386::rel_dyn_section(Layout* layout) |
| 265 | { |
| 266 | if (this->rel_dyn_ == NULL) |
| 267 | { |
| 268 | gold_assert(layout != NULL); |
| 269 | this->rel_dyn_ = new Reloc_section(); |
| 270 | layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| 271 | elfcpp::SHF_ALLOC, this->rel_dyn_); |
| 272 | } |
| 273 | return this->rel_dyn_; |
| 274 | } |
| 275 | |
| 276 | // A class to handle the PLT data. |
| 277 | |
| 278 | class Output_data_plt_i386 : public Output_section_data |
| 279 | { |
| 280 | public: |
| 281 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| 282 | |
| 283 | Output_data_plt_i386(Layout*, Output_data_space*, bool is_shared); |
| 284 | |
| 285 | // Add an entry to the PLT. |
| 286 | void |
| 287 | add_entry(Symbol* gsym); |
| 288 | |
| 289 | // Return the .rel.plt section data. |
| 290 | const Reloc_section* |
| 291 | rel_plt() const |
| 292 | { return this->rel_; } |
| 293 | |
| 294 | protected: |
| 295 | void |
| 296 | do_adjust_output_section(Output_section* os); |
| 297 | |
| 298 | private: |
| 299 | // The size of an entry in the PLT. |
| 300 | static const int plt_entry_size = 16; |
| 301 | |
| 302 | // The first entry in the PLT for an executable. |
| 303 | static unsigned char exec_first_plt_entry[plt_entry_size]; |
| 304 | |
| 305 | // The first entry in the PLT for a shared object. |
| 306 | static unsigned char dyn_first_plt_entry[plt_entry_size]; |
| 307 | |
| 308 | // Other entries in the PLT for an executable. |
| 309 | static unsigned char exec_plt_entry[plt_entry_size]; |
| 310 | |
| 311 | // Other entries in the PLT for a shared object. |
| 312 | static unsigned char dyn_plt_entry[plt_entry_size]; |
| 313 | |
| 314 | // Set the final size. |
| 315 | void |
| 316 | do_set_address(uint64_t, off_t) |
| 317 | { this->set_data_size((this->count_ + 1) * plt_entry_size); } |
| 318 | |
| 319 | // Write out the PLT data. |
| 320 | void |
| 321 | do_write(Output_file*); |
| 322 | |
| 323 | // The reloc section. |
| 324 | Reloc_section* rel_; |
| 325 | // The .got.plt section. |
| 326 | Output_data_space* got_plt_; |
| 327 | // The number of PLT entries. |
| 328 | unsigned int count_; |
| 329 | // Whether we are generated a shared object. |
| 330 | bool is_shared_; |
| 331 | }; |
| 332 | |
| 333 | // Create the PLT section. The ordinary .got section is an argument, |
| 334 | // since we need to refer to the start. We also create our own .got |
| 335 | // section just for PLT entries. |
| 336 | |
| 337 | Output_data_plt_i386::Output_data_plt_i386(Layout* layout, |
| 338 | Output_data_space* got_plt, |
| 339 | bool is_shared) |
| 340 | : Output_section_data(4), got_plt_(got_plt), is_shared_(is_shared) |
| 341 | { |
| 342 | this->rel_ = new Reloc_section(); |
| 343 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| 344 | elfcpp::SHF_ALLOC, this->rel_); |
| 345 | } |
| 346 | |
| 347 | // For some reason |
| 348 | |
| 349 | void |
| 350 | Output_data_plt_i386::do_adjust_output_section(Output_section* os) |
| 351 | { |
| 352 | // UnixWare sets the entsize of .plt to 4, and so does the old GNU |
| 353 | // linker, and so do we. |
| 354 | os->set_entsize(4); |
| 355 | } |
| 356 | |
| 357 | // Add an entry to the PLT. |
| 358 | |
| 359 | void |
| 360 | Output_data_plt_i386::add_entry(Symbol* gsym) |
| 361 | { |
| 362 | gold_assert(!gsym->has_plt_offset()); |
| 363 | |
| 364 | // Note that when setting the PLT offset we skip the initial |
| 365 | // reserved PLT entry. |
| 366 | gsym->set_plt_offset((this->count_ + 1) * plt_entry_size); |
| 367 | |
| 368 | ++this->count_; |
| 369 | |
| 370 | off_t got_offset = this->got_plt_->data_size(); |
| 371 | |
| 372 | // Every PLT entry needs a GOT entry which points back to the PLT |
| 373 | // entry (this will be changed by the dynamic linker, normally |
| 374 | // lazily when the function is called). |
| 375 | this->got_plt_->set_space_size(got_offset + 4); |
| 376 | |
| 377 | // Every PLT entry needs a reloc. |
| 378 | gsym->set_needs_dynsym_entry(); |
| 379 | this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_, |
| 380 | got_offset); |
| 381 | |
| 382 | // Note that we don't need to save the symbol. The contents of the |
| 383 | // PLT are independent of which symbols are used. The symbols only |
| 384 | // appear in the relocations. |
| 385 | } |
| 386 | |
| 387 | // The first entry in the PLT for an executable. |
| 388 | |
| 389 | unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] = |
| 390 | { |
| 391 | 0xff, 0x35, // pushl contents of memory address |
| 392 | 0, 0, 0, 0, // replaced with address of .got + 4 |
| 393 | 0xff, 0x25, // jmp indirect |
| 394 | 0, 0, 0, 0, // replaced with address of .got + 8 |
| 395 | 0, 0, 0, 0 // unused |
| 396 | }; |
| 397 | |
| 398 | // The first entry in the PLT for a shared object. |
| 399 | |
| 400 | unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] = |
| 401 | { |
| 402 | 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) |
| 403 | 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx) |
| 404 | 0, 0, 0, 0 // unused |
| 405 | }; |
| 406 | |
| 407 | // Subsequent entries in the PLT for an executable. |
| 408 | |
| 409 | unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] = |
| 410 | { |
| 411 | 0xff, 0x25, // jmp indirect |
| 412 | 0, 0, 0, 0, // replaced with address of symbol in .got |
| 413 | 0x68, // pushl immediate |
| 414 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 415 | 0xe9, // jmp relative |
| 416 | 0, 0, 0, 0 // replaced with offset to start of .plt |
| 417 | }; |
| 418 | |
| 419 | // Subsequent entries in the PLT for a shared object. |
| 420 | |
| 421 | unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] = |
| 422 | { |
| 423 | 0xff, 0xa3, // jmp *offset(%ebx) |
| 424 | 0, 0, 0, 0, // replaced with offset of symbol in .got |
| 425 | 0x68, // pushl immediate |
| 426 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 427 | 0xe9, // jmp relative |
| 428 | 0, 0, 0, 0 // replaced with offset to start of .plt |
| 429 | }; |
| 430 | |
| 431 | // Write out the PLT. This uses the hand-coded instructions above, |
| 432 | // and adjusts them as needed. This is all specified by the i386 ELF |
| 433 | // Processor Supplement. |
| 434 | |
| 435 | void |
| 436 | Output_data_plt_i386::do_write(Output_file* of) |
| 437 | { |
| 438 | const off_t offset = this->offset(); |
| 439 | const off_t oview_size = this->data_size(); |
| 440 | unsigned char* const oview = of->get_output_view(offset, oview_size); |
| 441 | |
| 442 | const off_t got_file_offset = this->got_plt_->offset(); |
| 443 | const off_t got_size = this->got_plt_->data_size(); |
| 444 | unsigned char* const got_view = of->get_output_view(got_file_offset, |
| 445 | got_size); |
| 446 | |
| 447 | unsigned char* pov = oview; |
| 448 | |
| 449 | elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); |
| 450 | elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); |
| 451 | |
| 452 | if (this->is_shared_) |
| 453 | memcpy(pov, dyn_first_plt_entry, plt_entry_size); |
| 454 | else |
| 455 | { |
| 456 | memcpy(pov, exec_first_plt_entry, plt_entry_size); |
| 457 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4); |
| 458 | elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8); |
| 459 | } |
| 460 | pov += plt_entry_size; |
| 461 | |
| 462 | unsigned char* got_pov = got_view; |
| 463 | |
| 464 | memset(got_pov, 0, 12); |
| 465 | got_pov += 12; |
| 466 | |
| 467 | const int rel_size = elfcpp::Elf_sizes<32>::rel_size; |
| 468 | |
| 469 | unsigned int plt_offset = plt_entry_size; |
| 470 | unsigned int plt_rel_offset = 0; |
| 471 | unsigned int got_offset = 12; |
| 472 | const unsigned int count = this->count_; |
| 473 | for (unsigned int i = 0; |
| 474 | i < count; |
| 475 | ++i, |
| 476 | pov += plt_entry_size, |
| 477 | got_pov += 4, |
| 478 | plt_offset += plt_entry_size, |
| 479 | plt_rel_offset += rel_size, |
| 480 | got_offset += 4) |
| 481 | { |
| 482 | // Set and adjust the PLT entry itself. |
| 483 | |
| 484 | if (this->is_shared_) |
| 485 | { |
| 486 | memcpy(pov, dyn_plt_entry, plt_entry_size); |
| 487 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); |
| 488 | } |
| 489 | else |
| 490 | { |
| 491 | memcpy(pov, exec_plt_entry, plt_entry_size); |
| 492 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| 493 | (got_address |
| 494 | + got_offset)); |
| 495 | } |
| 496 | |
| 497 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| 498 | elfcpp::Swap<32, false>::writeval(pov + 12, |
| 499 | - (plt_offset + plt_entry_size)); |
| 500 | |
| 501 | // Set the entry in the GOT. |
| 502 | elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6); |
| 503 | } |
| 504 | |
| 505 | gold_assert(pov - oview == oview_size); |
| 506 | gold_assert(got_pov - got_view == got_size); |
| 507 | |
| 508 | of->write_output_view(offset, oview_size, oview); |
| 509 | of->write_output_view(got_file_offset, got_size, got_view); |
| 510 | } |
| 511 | |
| 512 | // Create a PLT entry for a global symbol. |
| 513 | |
| 514 | void |
| 515 | Target_i386::make_plt_entry(const General_options* options, |
| 516 | Symbol_table* symtab, Layout* layout, Symbol* gsym) |
| 517 | { |
| 518 | if (gsym->has_plt_offset()) |
| 519 | return; |
| 520 | |
| 521 | if (this->plt_ == NULL) |
| 522 | { |
| 523 | // Create the GOT sections first. |
| 524 | this->got_section(options, symtab, layout); |
| 525 | |
| 526 | this->plt_ = new Output_data_plt_i386(layout, this->got_plt_, |
| 527 | options->is_shared()); |
| 528 | layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| 529 | (elfcpp::SHF_ALLOC |
| 530 | | elfcpp::SHF_EXECINSTR), |
| 531 | this->plt_); |
| 532 | } |
| 533 | |
| 534 | this->plt_->add_entry(gsym); |
| 535 | } |
| 536 | |
| 537 | // Handle a relocation against a non-function symbol defined in a |
| 538 | // dynamic object. The traditional way to handle this is to generate |
| 539 | // a COPY relocation to copy the variable at runtime from the shared |
| 540 | // object into the executable's data segment. However, this is |
| 541 | // undesirable in general, as if the size of the object changes in the |
| 542 | // dynamic object, the executable will no longer work correctly. If |
| 543 | // this relocation is in a writable section, then we can create a |
| 544 | // dynamic reloc and the dynamic linker will resolve it to the correct |
| 545 | // address at runtime. However, we do not want do that if the |
| 546 | // relocation is in a read-only section, as it would prevent the |
| 547 | // readonly segment from being shared. And if we have to eventually |
| 548 | // generate a COPY reloc, then any dynamic relocations will be |
| 549 | // useless. So this means that if this is a writable section, we need |
| 550 | // to save the relocation until we see whether we have to create a |
| 551 | // COPY relocation for this symbol for any other relocation. |
| 552 | |
| 553 | void |
| 554 | Target_i386::copy_reloc(const General_options* options, |
| 555 | Symbol_table* symtab, |
| 556 | Layout* layout, |
| 557 | Sized_relobj<32, false>* object, |
| 558 | unsigned int data_shndx, Symbol* gsym, |
| 559 | const elfcpp::Rel<32, false>& rel) |
| 560 | { |
| 561 | Sized_symbol<32>* ssym; |
| 562 | ssym = symtab->get_sized_symbol SELECT_SIZE_NAME(32) (gsym |
| 563 | SELECT_SIZE(32)); |
| 564 | |
| 565 | if (!Copy_relocs<32, false>::need_copy_reloc(options, object, |
| 566 | data_shndx, ssym)) |
| 567 | { |
| 568 | // So far we do not need a COPY reloc. Save this relocation. |
| 569 | // If it turns out that we never need a COPY reloc for this |
| 570 | // symbol, then we will emit the relocation. |
| 571 | if (this->copy_relocs_ == NULL) |
| 572 | this->copy_relocs_ = new Copy_relocs<32, false>(); |
| 573 | this->copy_relocs_->save(ssym, object, data_shndx, rel); |
| 574 | } |
| 575 | else |
| 576 | { |
| 577 | // Allocate space for this symbol in the .bss section. |
| 578 | |
| 579 | elfcpp::Elf_types<32>::Elf_WXword symsize = ssym->symsize(); |
| 580 | |
| 581 | // There is no defined way to determine the required alignment |
| 582 | // of the symbol. We pick the alignment based on the size. We |
| 583 | // set an arbitrary maximum of 256. |
| 584 | unsigned int align; |
| 585 | for (align = 1; align < 512; align <<= 1) |
| 586 | if ((symsize & align) != 0) |
| 587 | break; |
| 588 | |
| 589 | if (this->dynbss_ == NULL) |
| 590 | { |
| 591 | this->dynbss_ = new Output_data_space(align); |
| 592 | layout->add_output_section_data(".bss", |
| 593 | elfcpp::SHT_NOBITS, |
| 594 | (elfcpp::SHF_ALLOC |
| 595 | | elfcpp::SHF_WRITE), |
| 596 | this->dynbss_); |
| 597 | } |
| 598 | |
| 599 | Output_data_space* dynbss = this->dynbss_; |
| 600 | |
| 601 | if (align > dynbss->addralign()) |
| 602 | dynbss->set_space_alignment(align); |
| 603 | |
| 604 | off_t dynbss_size = dynbss->data_size(); |
| 605 | dynbss_size = align_address(dynbss_size, align); |
| 606 | off_t offset = dynbss_size; |
| 607 | dynbss->set_space_size(dynbss_size + symsize); |
| 608 | |
| 609 | // Define the symbol in the .dynbss section. |
| 610 | symtab->define_in_output_data(this, ssym->name(), ssym->version(), |
| 611 | dynbss, offset, symsize, ssym->type(), |
| 612 | ssym->binding(), ssym->visibility(), |
| 613 | ssym->nonvis(), false, false); |
| 614 | |
| 615 | // Add the COPY reloc. |
| 616 | ssym->set_needs_dynsym_entry(); |
| 617 | Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| 618 | rel_dyn->add_global(ssym, elfcpp::R_386_COPY, dynbss, offset); |
| 619 | } |
| 620 | } |
| 621 | |
| 622 | // Optimize the TLS relocation type based on what we know about the |
| 623 | // symbol. IS_FINAL is true if the final address of this symbol is |
| 624 | // known at link time. |
| 625 | |
| 626 | unsigned int |
| 627 | Target_i386::optimize_tls_reloc(const General_options* options, |
| 628 | bool is_final, |
| 629 | int r_type) |
| 630 | { |
| 631 | // If we are generating a shared library, then we can't do anything |
| 632 | // in the linker. |
| 633 | if (options->is_shared()) |
| 634 | return r_type; |
| 635 | |
| 636 | switch (r_type) |
| 637 | { |
| 638 | case elfcpp::R_386_TLS_GD: |
| 639 | case elfcpp::R_386_TLS_GOTDESC: |
| 640 | case elfcpp::R_386_TLS_DESC_CALL: |
| 641 | // These are Global-Dynamic which permits fully general TLS |
| 642 | // access. Since we know that we are generating an executable, |
| 643 | // we can convert this to Initial-Exec. If we also know that |
| 644 | // this is a local symbol, we can further switch to Local-Exec. |
| 645 | if (is_final) |
| 646 | return elfcpp::R_386_TLS_LE_32; |
| 647 | return elfcpp::R_386_TLS_IE_32; |
| 648 | |
| 649 | case elfcpp::R_386_TLS_LDM: |
| 650 | // This is Local-Dynamic, which refers to a local symbol in the |
| 651 | // dynamic TLS block. Since we know that we generating an |
| 652 | // executable, we can switch to Local-Exec. |
| 653 | return elfcpp::R_386_TLS_LE_32; |
| 654 | |
| 655 | case elfcpp::R_386_TLS_LDO_32: |
| 656 | // Another type of Local-Dynamic relocation. |
| 657 | return elfcpp::R_386_TLS_LE; |
| 658 | |
| 659 | case elfcpp::R_386_TLS_IE: |
| 660 | case elfcpp::R_386_TLS_GOTIE: |
| 661 | case elfcpp::R_386_TLS_IE_32: |
| 662 | // These are Initial-Exec relocs which get the thread offset |
| 663 | // from the GOT. If we know that we are linking against the |
| 664 | // local symbol, we can switch to Local-Exec, which links the |
| 665 | // thread offset into the instruction. |
| 666 | if (is_final) |
| 667 | return elfcpp::R_386_TLS_LE_32; |
| 668 | return r_type; |
| 669 | |
| 670 | case elfcpp::R_386_TLS_LE: |
| 671 | case elfcpp::R_386_TLS_LE_32: |
| 672 | // When we already have Local-Exec, there is nothing further we |
| 673 | // can do. |
| 674 | return r_type; |
| 675 | |
| 676 | default: |
| 677 | gold_unreachable(); |
| 678 | } |
| 679 | } |
| 680 | |
| 681 | // Scan a relocation for a local symbol. |
| 682 | |
| 683 | inline void |
| 684 | Target_i386::Scan::local(const General_options& options, |
| 685 | Symbol_table* symtab, |
| 686 | Layout* layout, |
| 687 | Target_i386* target, |
| 688 | Sized_relobj<32, false>* object, |
| 689 | unsigned int, |
| 690 | const elfcpp::Rel<32, false>&, |
| 691 | unsigned int r_type, |
| 692 | const elfcpp::Sym<32, false>&) |
| 693 | { |
| 694 | switch (r_type) |
| 695 | { |
| 696 | case elfcpp::R_386_NONE: |
| 697 | case elfcpp::R_386_GNU_VTINHERIT: |
| 698 | case elfcpp::R_386_GNU_VTENTRY: |
| 699 | break; |
| 700 | |
| 701 | case elfcpp::R_386_32: |
| 702 | case elfcpp::R_386_16: |
| 703 | case elfcpp::R_386_8: |
| 704 | // FIXME: If we are generating a shared object we need to copy |
| 705 | // this relocation into the object. |
| 706 | gold_assert(!options.is_shared()); |
| 707 | break; |
| 708 | |
| 709 | case elfcpp::R_386_PC32: |
| 710 | case elfcpp::R_386_PC16: |
| 711 | case elfcpp::R_386_PC8: |
| 712 | break; |
| 713 | |
| 714 | case elfcpp::R_386_GOTOFF: |
| 715 | case elfcpp::R_386_GOTPC: |
| 716 | // We need a GOT section. |
| 717 | target->got_section(&options, symtab, layout); |
| 718 | break; |
| 719 | |
| 720 | case elfcpp::R_386_COPY: |
| 721 | case elfcpp::R_386_GLOB_DAT: |
| 722 | case elfcpp::R_386_JUMP_SLOT: |
| 723 | case elfcpp::R_386_RELATIVE: |
| 724 | case elfcpp::R_386_TLS_TPOFF: |
| 725 | case elfcpp::R_386_TLS_DTPMOD32: |
| 726 | case elfcpp::R_386_TLS_DTPOFF32: |
| 727 | case elfcpp::R_386_TLS_TPOFF32: |
| 728 | case elfcpp::R_386_TLS_DESC: |
| 729 | fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"), |
| 730 | program_name, object->name().c_str(), r_type); |
| 731 | gold_exit(false); |
| 732 | break; |
| 733 | |
| 734 | case elfcpp::R_386_TLS_IE: |
| 735 | case elfcpp::R_386_TLS_GOTIE: |
| 736 | case elfcpp::R_386_TLS_LE: |
| 737 | case elfcpp::R_386_TLS_GD: |
| 738 | case elfcpp::R_386_TLS_LDM: |
| 739 | case elfcpp::R_386_TLS_LDO_32: |
| 740 | case elfcpp::R_386_TLS_IE_32: |
| 741 | case elfcpp::R_386_TLS_LE_32: |
| 742 | case elfcpp::R_386_TLS_GOTDESC: |
| 743 | case elfcpp::R_386_TLS_DESC_CALL: |
| 744 | r_type = Target_i386::optimize_tls_reloc(&options, |
| 745 | !options.is_shared(), |
| 746 | r_type); |
| 747 | switch (r_type) |
| 748 | { |
| 749 | case elfcpp::R_386_TLS_LE: |
| 750 | case elfcpp::R_386_TLS_LE_32: |
| 751 | // FIXME: If generating a shared object, we need to copy |
| 752 | // this relocation into the object. |
| 753 | gold_assert(!options.is_shared()); |
| 754 | break; |
| 755 | |
| 756 | case elfcpp::R_386_TLS_IE: |
| 757 | case elfcpp::R_386_TLS_GOTIE: |
| 758 | case elfcpp::R_386_TLS_GD: |
| 759 | case elfcpp::R_386_TLS_LDM: |
| 760 | case elfcpp::R_386_TLS_LDO_32: |
| 761 | case elfcpp::R_386_TLS_IE_32: |
| 762 | case elfcpp::R_386_TLS_GOTDESC: |
| 763 | case elfcpp::R_386_TLS_DESC_CALL: |
| 764 | fprintf(stderr, |
| 765 | _("%s: %s: unsupported reloc %u against local symbol\n"), |
| 766 | program_name, object->name().c_str(), r_type); |
| 767 | break; |
| 768 | } |
| 769 | break; |
| 770 | |
| 771 | case elfcpp::R_386_GOT32: |
| 772 | case elfcpp::R_386_PLT32: |
| 773 | case elfcpp::R_386_32PLT: |
| 774 | case elfcpp::R_386_TLS_GD_32: |
| 775 | case elfcpp::R_386_TLS_GD_PUSH: |
| 776 | case elfcpp::R_386_TLS_GD_CALL: |
| 777 | case elfcpp::R_386_TLS_GD_POP: |
| 778 | case elfcpp::R_386_TLS_LDM_32: |
| 779 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 780 | case elfcpp::R_386_TLS_LDM_CALL: |
| 781 | case elfcpp::R_386_TLS_LDM_POP: |
| 782 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 783 | default: |
| 784 | fprintf(stderr, _("%s: %s: unsupported reloc %u against local symbol\n"), |
| 785 | program_name, object->name().c_str(), r_type); |
| 786 | break; |
| 787 | } |
| 788 | } |
| 789 | |
| 790 | // Scan a relocation for a global symbol. |
| 791 | |
| 792 | inline void |
| 793 | Target_i386::Scan::global(const General_options& options, |
| 794 | Symbol_table* symtab, |
| 795 | Layout* layout, |
| 796 | Target_i386* target, |
| 797 | Sized_relobj<32, false>* object, |
| 798 | unsigned int data_shndx, |
| 799 | const elfcpp::Rel<32, false>& reloc, |
| 800 | unsigned int r_type, |
| 801 | Symbol* gsym) |
| 802 | { |
| 803 | switch (r_type) |
| 804 | { |
| 805 | case elfcpp::R_386_NONE: |
| 806 | case elfcpp::R_386_GNU_VTINHERIT: |
| 807 | case elfcpp::R_386_GNU_VTENTRY: |
| 808 | break; |
| 809 | |
| 810 | case elfcpp::R_386_32: |
| 811 | case elfcpp::R_386_PC32: |
| 812 | case elfcpp::R_386_16: |
| 813 | case elfcpp::R_386_PC16: |
| 814 | case elfcpp::R_386_8: |
| 815 | case elfcpp::R_386_PC8: |
| 816 | // FIXME: If we are generating a shared object we may need to |
| 817 | // copy this relocation into the object. If this symbol is |
| 818 | // defined in a shared object, we may need to copy this |
| 819 | // relocation in order to avoid a COPY relocation. |
| 820 | gold_assert(!options.is_shared()); |
| 821 | |
| 822 | if (gsym->is_from_dynobj()) |
| 823 | { |
| 824 | // This symbol is defined in a dynamic object. If it is a |
| 825 | // function, we make a PLT entry. Otherwise we need to |
| 826 | // either generate a COPY reloc or copy this reloc. |
| 827 | if (gsym->type() == elfcpp::STT_FUNC) |
| 828 | target->make_plt_entry(&options, symtab, layout, gsym); |
| 829 | else |
| 830 | target->copy_reloc(&options, symtab, layout, object, data_shndx, |
| 831 | gsym, reloc); |
| 832 | } |
| 833 | |
| 834 | break; |
| 835 | |
| 836 | case elfcpp::R_386_GOT32: |
| 837 | // The symbol requires a GOT entry. |
| 838 | if (target->got_section(&options, symtab, layout)->add_global(gsym)) |
| 839 | { |
| 840 | // If this symbol is not fully resolved, we need to add a |
| 841 | // dynamic relocation for it. |
| 842 | if (!gsym->final_value_is_known(&options)) |
| 843 | gold_unreachable(); |
| 844 | } |
| 845 | break; |
| 846 | |
| 847 | case elfcpp::R_386_PLT32: |
| 848 | // If the symbol is fully resolved, this is just a PC32 reloc. |
| 849 | // Otherwise we need a PLT entry. |
| 850 | if (gsym->final_value_is_known(&options)) |
| 851 | break; |
| 852 | target->make_plt_entry(&options, symtab, layout, gsym); |
| 853 | break; |
| 854 | |
| 855 | case elfcpp::R_386_GOTOFF: |
| 856 | case elfcpp::R_386_GOTPC: |
| 857 | // We need a GOT section. |
| 858 | target->got_section(&options, symtab, layout); |
| 859 | break; |
| 860 | |
| 861 | case elfcpp::R_386_COPY: |
| 862 | case elfcpp::R_386_GLOB_DAT: |
| 863 | case elfcpp::R_386_JUMP_SLOT: |
| 864 | case elfcpp::R_386_RELATIVE: |
| 865 | case elfcpp::R_386_TLS_TPOFF: |
| 866 | case elfcpp::R_386_TLS_DTPMOD32: |
| 867 | case elfcpp::R_386_TLS_DTPOFF32: |
| 868 | case elfcpp::R_386_TLS_TPOFF32: |
| 869 | case elfcpp::R_386_TLS_DESC: |
| 870 | fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"), |
| 871 | program_name, object->name().c_str(), r_type); |
| 872 | gold_exit(false); |
| 873 | break; |
| 874 | |
| 875 | case elfcpp::R_386_TLS_IE: |
| 876 | case elfcpp::R_386_TLS_GOTIE: |
| 877 | case elfcpp::R_386_TLS_LE: |
| 878 | case elfcpp::R_386_TLS_GD: |
| 879 | case elfcpp::R_386_TLS_LDM: |
| 880 | case elfcpp::R_386_TLS_LDO_32: |
| 881 | case elfcpp::R_386_TLS_IE_32: |
| 882 | case elfcpp::R_386_TLS_LE_32: |
| 883 | case elfcpp::R_386_TLS_GOTDESC: |
| 884 | case elfcpp::R_386_TLS_DESC_CALL: |
| 885 | { |
| 886 | const bool is_final = gsym->final_value_is_known(&options); |
| 887 | r_type = Target_i386::optimize_tls_reloc(&options, is_final, r_type); |
| 888 | switch (r_type) |
| 889 | { |
| 890 | case elfcpp::R_386_TLS_LE: |
| 891 | case elfcpp::R_386_TLS_LE_32: |
| 892 | // FIXME: If generating a shared object, we need to copy |
| 893 | // this relocation into the object. |
| 894 | gold_assert(!options.is_shared()); |
| 895 | break; |
| 896 | |
| 897 | case elfcpp::R_386_TLS_IE: |
| 898 | case elfcpp::R_386_TLS_GOTIE: |
| 899 | case elfcpp::R_386_TLS_GD: |
| 900 | case elfcpp::R_386_TLS_LDM: |
| 901 | case elfcpp::R_386_TLS_LDO_32: |
| 902 | case elfcpp::R_386_TLS_IE_32: |
| 903 | case elfcpp::R_386_TLS_GOTDESC: |
| 904 | case elfcpp::R_386_TLS_DESC_CALL: |
| 905 | fprintf(stderr, |
| 906 | _("%s: %s: unsupported reloc %u " |
| 907 | "against global symbol %s\n"), |
| 908 | program_name, object->name().c_str(), r_type, |
| 909 | gsym->name()); |
| 910 | break; |
| 911 | } |
| 912 | } |
| 913 | break; |
| 914 | |
| 915 | case elfcpp::R_386_32PLT: |
| 916 | case elfcpp::R_386_TLS_GD_32: |
| 917 | case elfcpp::R_386_TLS_GD_PUSH: |
| 918 | case elfcpp::R_386_TLS_GD_CALL: |
| 919 | case elfcpp::R_386_TLS_GD_POP: |
| 920 | case elfcpp::R_386_TLS_LDM_32: |
| 921 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 922 | case elfcpp::R_386_TLS_LDM_CALL: |
| 923 | case elfcpp::R_386_TLS_LDM_POP: |
| 924 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 925 | default: |
| 926 | fprintf(stderr, |
| 927 | _("%s: %s: unsupported reloc %u against global symbol %s\n"), |
| 928 | program_name, object->name().c_str(), r_type, gsym->name()); |
| 929 | break; |
| 930 | } |
| 931 | } |
| 932 | |
| 933 | // Scan relocations for a section. |
| 934 | |
| 935 | void |
| 936 | Target_i386::scan_relocs(const General_options& options, |
| 937 | Symbol_table* symtab, |
| 938 | Layout* layout, |
| 939 | Sized_relobj<32, false>* object, |
| 940 | unsigned int data_shndx, |
| 941 | unsigned int sh_type, |
| 942 | const unsigned char* prelocs, |
| 943 | size_t reloc_count, |
| 944 | size_t local_symbol_count, |
| 945 | const unsigned char* plocal_symbols, |
| 946 | Symbol** global_symbols) |
| 947 | { |
| 948 | if (sh_type == elfcpp::SHT_RELA) |
| 949 | { |
| 950 | fprintf(stderr, _("%s: %s: unsupported RELA reloc section\n"), |
| 951 | program_name, object->name().c_str()); |
| 952 | gold_exit(false); |
| 953 | } |
| 954 | |
| 955 | gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL, |
| 956 | Target_i386::Scan>( |
| 957 | options, |
| 958 | symtab, |
| 959 | layout, |
| 960 | this, |
| 961 | object, |
| 962 | data_shndx, |
| 963 | prelocs, |
| 964 | reloc_count, |
| 965 | local_symbol_count, |
| 966 | plocal_symbols, |
| 967 | global_symbols); |
| 968 | } |
| 969 | |
| 970 | // Finalize the sections. |
| 971 | |
| 972 | void |
| 973 | Target_i386::do_finalize_sections(const General_options* options, |
| 974 | Layout* layout) |
| 975 | { |
| 976 | // Fill in some more dynamic tags. |
| 977 | Output_data_dynamic* const odyn = layout->dynamic_data(); |
| 978 | if (odyn != NULL) |
| 979 | { |
| 980 | if (this->got_plt_ != NULL) |
| 981 | odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_); |
| 982 | |
| 983 | if (this->plt_ != NULL) |
| 984 | { |
| 985 | const Output_data* od = this->plt_->rel_plt(); |
| 986 | odyn->add_section_size(elfcpp::DT_PLTRELSZ, od); |
| 987 | odyn->add_section_address(elfcpp::DT_JMPREL, od); |
| 988 | odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL); |
| 989 | } |
| 990 | |
| 991 | if (this->rel_dyn_ != NULL) |
| 992 | { |
| 993 | const Output_data* od = this->rel_dyn_; |
| 994 | odyn->add_section_address(elfcpp::DT_REL, od); |
| 995 | odyn->add_section_size(elfcpp::DT_RELSZ, od); |
| 996 | odyn->add_constant(elfcpp::DT_RELENT, |
| 997 | elfcpp::Elf_sizes<32>::rel_size); |
| 998 | } |
| 999 | |
| 1000 | if (!options->is_shared()) |
| 1001 | { |
| 1002 | // The value of the DT_DEBUG tag is filled in by the dynamic |
| 1003 | // linker at run time, and used by the debugger. |
| 1004 | odyn->add_constant(elfcpp::DT_DEBUG, 0); |
| 1005 | } |
| 1006 | } |
| 1007 | |
| 1008 | // Emit any relocs we saved in an attempt to avoid generating COPY |
| 1009 | // relocs. |
| 1010 | if (this->copy_relocs_ == NULL) |
| 1011 | return; |
| 1012 | if (this->copy_relocs_->any_to_emit()) |
| 1013 | { |
| 1014 | Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| 1015 | this->copy_relocs_->emit(rel_dyn); |
| 1016 | } |
| 1017 | delete this->copy_relocs_; |
| 1018 | this->copy_relocs_ = NULL; |
| 1019 | } |
| 1020 | |
| 1021 | // Perform a relocation. |
| 1022 | |
| 1023 | inline bool |
| 1024 | Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, |
| 1025 | Target_i386* target, |
| 1026 | size_t relnum, |
| 1027 | const elfcpp::Rel<32, false>& rel, |
| 1028 | unsigned int r_type, |
| 1029 | const Sized_symbol<32>* gsym, |
| 1030 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 1031 | unsigned char* view, |
| 1032 | elfcpp::Elf_types<32>::Elf_Addr address, |
| 1033 | off_t view_size) |
| 1034 | { |
| 1035 | if (this->skip_call_tls_get_addr_) |
| 1036 | { |
| 1037 | if (r_type != elfcpp::R_386_PLT32 |
| 1038 | || gsym == NULL |
| 1039 | || strcmp(gsym->name(), "___tls_get_addr") != 0) |
| 1040 | { |
| 1041 | fprintf(stderr, _("%s: %s: missing expected TLS relocation\n"), |
| 1042 | program_name, |
| 1043 | relinfo->location(relnum, rel.get_r_offset()).c_str()); |
| 1044 | gold_exit(false); |
| 1045 | } |
| 1046 | |
| 1047 | this->skip_call_tls_get_addr_ = false; |
| 1048 | |
| 1049 | return false; |
| 1050 | } |
| 1051 | |
| 1052 | // Pick the value to use for symbols defined in shared objects. |
| 1053 | if (gsym != NULL && gsym->is_from_dynobj()) |
| 1054 | { |
| 1055 | if (gsym->has_plt_offset()) |
| 1056 | value = target->plt_section()->address() + gsym->plt_offset(); |
| 1057 | else |
| 1058 | gold_unreachable(); |
| 1059 | } |
| 1060 | |
| 1061 | switch (r_type) |
| 1062 | { |
| 1063 | case elfcpp::R_386_NONE: |
| 1064 | case elfcpp::R_386_GNU_VTINHERIT: |
| 1065 | case elfcpp::R_386_GNU_VTENTRY: |
| 1066 | break; |
| 1067 | |
| 1068 | case elfcpp::R_386_32: |
| 1069 | Relocate_functions<32, false>::rel32(view, value); |
| 1070 | break; |
| 1071 | |
| 1072 | case elfcpp::R_386_PC32: |
| 1073 | Relocate_functions<32, false>::pcrel32(view, value, address); |
| 1074 | break; |
| 1075 | |
| 1076 | case elfcpp::R_386_16: |
| 1077 | Relocate_functions<32, false>::rel16(view, value); |
| 1078 | break; |
| 1079 | |
| 1080 | case elfcpp::R_386_PC16: |
| 1081 | Relocate_functions<32, false>::pcrel16(view, value, address); |
| 1082 | break; |
| 1083 | |
| 1084 | case elfcpp::R_386_8: |
| 1085 | Relocate_functions<32, false>::rel8(view, value); |
| 1086 | break; |
| 1087 | |
| 1088 | case elfcpp::R_386_PC8: |
| 1089 | Relocate_functions<32, false>::pcrel8(view, value, address); |
| 1090 | break; |
| 1091 | |
| 1092 | case elfcpp::R_386_PLT32: |
| 1093 | gold_assert(gsym->has_plt_offset() |
| 1094 | || gsym->final_value_is_known(relinfo->options)); |
| 1095 | Relocate_functions<32, false>::pcrel32(view, value, address); |
| 1096 | break; |
| 1097 | |
| 1098 | case elfcpp::R_386_GOT32: |
| 1099 | // Local GOT offsets not yet supported. |
| 1100 | gold_assert(gsym); |
| 1101 | gold_assert(gsym->has_got_offset()); |
| 1102 | value = gsym->got_offset(); |
| 1103 | Relocate_functions<32, false>::rel32(view, value); |
| 1104 | break; |
| 1105 | |
| 1106 | case elfcpp::R_386_GOTOFF: |
| 1107 | value -= target->got_section(NULL, NULL, NULL)->address(); |
| 1108 | Relocate_functions<32, false>::rel32(view, value); |
| 1109 | break; |
| 1110 | |
| 1111 | case elfcpp::R_386_GOTPC: |
| 1112 | value = target->got_section(NULL, NULL, NULL)->address(); |
| 1113 | Relocate_functions<32, false>::pcrel32(view, value, address); |
| 1114 | break; |
| 1115 | |
| 1116 | case elfcpp::R_386_COPY: |
| 1117 | case elfcpp::R_386_GLOB_DAT: |
| 1118 | case elfcpp::R_386_JUMP_SLOT: |
| 1119 | case elfcpp::R_386_RELATIVE: |
| 1120 | case elfcpp::R_386_TLS_TPOFF: |
| 1121 | case elfcpp::R_386_TLS_DTPMOD32: |
| 1122 | case elfcpp::R_386_TLS_DTPOFF32: |
| 1123 | case elfcpp::R_386_TLS_TPOFF32: |
| 1124 | case elfcpp::R_386_TLS_DESC: |
| 1125 | fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"), |
| 1126 | program_name, |
| 1127 | relinfo->location(relnum, rel.get_r_offset()).c_str(), |
| 1128 | r_type); |
| 1129 | gold_exit(false); |
| 1130 | break; |
| 1131 | |
| 1132 | case elfcpp::R_386_TLS_IE: |
| 1133 | case elfcpp::R_386_TLS_GOTIE: |
| 1134 | case elfcpp::R_386_TLS_LE: |
| 1135 | case elfcpp::R_386_TLS_GD: |
| 1136 | case elfcpp::R_386_TLS_LDM: |
| 1137 | case elfcpp::R_386_TLS_LDO_32: |
| 1138 | case elfcpp::R_386_TLS_IE_32: |
| 1139 | case elfcpp::R_386_TLS_LE_32: |
| 1140 | case elfcpp::R_386_TLS_GOTDESC: |
| 1141 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1142 | this->relocate_tls(relinfo, relnum, rel, r_type, gsym, value, view, |
| 1143 | address, view_size); |
| 1144 | break; |
| 1145 | |
| 1146 | case elfcpp::R_386_32PLT: |
| 1147 | case elfcpp::R_386_TLS_GD_32: |
| 1148 | case elfcpp::R_386_TLS_GD_PUSH: |
| 1149 | case elfcpp::R_386_TLS_GD_CALL: |
| 1150 | case elfcpp::R_386_TLS_GD_POP: |
| 1151 | case elfcpp::R_386_TLS_LDM_32: |
| 1152 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 1153 | case elfcpp::R_386_TLS_LDM_CALL: |
| 1154 | case elfcpp::R_386_TLS_LDM_POP: |
| 1155 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 1156 | default: |
| 1157 | fprintf(stderr, _("%s: %s: unsupported reloc %u\n"), |
| 1158 | program_name, |
| 1159 | relinfo->location(relnum, rel.get_r_offset()).c_str(), |
| 1160 | r_type); |
| 1161 | // gold_exit(false); |
| 1162 | break; |
| 1163 | } |
| 1164 | |
| 1165 | return true; |
| 1166 | } |
| 1167 | |
| 1168 | // Perform a TLS relocation. |
| 1169 | |
| 1170 | inline void |
| 1171 | Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo, |
| 1172 | size_t relnum, |
| 1173 | const elfcpp::Rel<32, false>& rel, |
| 1174 | unsigned int r_type, |
| 1175 | const Sized_symbol<32>* gsym, |
| 1176 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 1177 | unsigned char* view, |
| 1178 | elfcpp::Elf_types<32>::Elf_Addr, |
| 1179 | off_t view_size) |
| 1180 | { |
| 1181 | Output_segment* tls_segment = relinfo->layout->tls_segment(); |
| 1182 | if (tls_segment == NULL) |
| 1183 | { |
| 1184 | fprintf(stderr, _("%s: %s: TLS reloc but no TLS segment\n"), |
| 1185 | program_name, |
| 1186 | relinfo->location(relnum, rel.get_r_offset()).c_str()); |
| 1187 | gold_exit(false); |
| 1188 | } |
| 1189 | |
| 1190 | const bool is_final = (gsym == NULL |
| 1191 | ? !relinfo->options->is_shared() |
| 1192 | : gsym->final_value_is_known(relinfo->options)); |
| 1193 | const unsigned int opt_r_type = |
| 1194 | Target_i386::optimize_tls_reloc(relinfo->options, is_final, r_type); |
| 1195 | switch (r_type) |
| 1196 | { |
| 1197 | case elfcpp::R_386_TLS_LE_32: |
| 1198 | value = tls_segment->vaddr() + tls_segment->memsz() - value; |
| 1199 | Relocate_functions<32, false>::rel32(view, value); |
| 1200 | break; |
| 1201 | |
| 1202 | case elfcpp::R_386_TLS_LE: |
| 1203 | value = value - (tls_segment->vaddr() + tls_segment->memsz()); |
| 1204 | Relocate_functions<32, false>::rel32(view, value); |
| 1205 | break; |
| 1206 | |
| 1207 | case elfcpp::R_386_TLS_IE: |
| 1208 | case elfcpp::R_386_TLS_GOTIE: |
| 1209 | case elfcpp::R_386_TLS_IE_32: |
| 1210 | if (opt_r_type == elfcpp::R_386_TLS_LE_32) |
| 1211 | { |
| 1212 | Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment, |
| 1213 | rel, r_type, value, view, |
| 1214 | view_size); |
| 1215 | break; |
| 1216 | } |
| 1217 | fprintf(stderr, _("%s: %s: unsupported reloc type %u\n"), |
| 1218 | program_name, |
| 1219 | relinfo->location(relnum, rel.get_r_offset()).c_str(), |
| 1220 | r_type); |
| 1221 | // gold_exit(false); |
| 1222 | break; |
| 1223 | |
| 1224 | case elfcpp::R_386_TLS_GD: |
| 1225 | if (opt_r_type == elfcpp::R_386_TLS_LE_32) |
| 1226 | { |
| 1227 | this->tls_gd_to_le(relinfo, relnum, tls_segment, |
| 1228 | rel, r_type, value, view, |
| 1229 | view_size); |
| 1230 | break; |
| 1231 | } |
| 1232 | fprintf(stderr, _("%s: %s: unsupported reloc %u\n"), |
| 1233 | program_name, |
| 1234 | relinfo->location(relnum, rel.get_r_offset()).c_str(), |
| 1235 | r_type); |
| 1236 | // gold_exit(false); |
| 1237 | break; |
| 1238 | |
| 1239 | case elfcpp::R_386_TLS_LDM: |
| 1240 | case elfcpp::R_386_TLS_LDO_32: |
| 1241 | case elfcpp::R_386_TLS_GOTDESC: |
| 1242 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1243 | fprintf(stderr, _("%s: %s: unsupported reloc %u\n"), |
| 1244 | program_name, |
| 1245 | relinfo->location(relnum, rel.get_r_offset()).c_str(), |
| 1246 | r_type); |
| 1247 | // gold_exit(false); |
| 1248 | break; |
| 1249 | } |
| 1250 | } |
| 1251 | |
| 1252 | // Do a relocation in which we convert a TLS Initial-Exec to a |
| 1253 | // Local-Exec. |
| 1254 | |
| 1255 | inline void |
| 1256 | Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo, |
| 1257 | size_t relnum, |
| 1258 | Output_segment* tls_segment, |
| 1259 | const elfcpp::Rel<32, false>& rel, |
| 1260 | unsigned int r_type, |
| 1261 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 1262 | unsigned char* view, |
| 1263 | off_t view_size) |
| 1264 | { |
| 1265 | // We have to actually change the instructions, which means that we |
| 1266 | // need to examine the opcodes to figure out which instruction we |
| 1267 | // are looking at. |
| 1268 | if (r_type == elfcpp::R_386_TLS_IE) |
| 1269 | { |
| 1270 | // movl %gs:XX,%eax ==> movl $YY,%eax |
| 1271 | // movl %gs:XX,%reg ==> movl $YY,%reg |
| 1272 | // addl %gs:XX,%reg ==> addl $YY,%reg |
| 1273 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -1); |
| 1274 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4); |
| 1275 | |
| 1276 | unsigned char op1 = view[-1]; |
| 1277 | if (op1 == 0xa1) |
| 1278 | { |
| 1279 | // movl XX,%eax ==> movl $YY,%eax |
| 1280 | view[-1] = 0xb8; |
| 1281 | } |
| 1282 | else |
| 1283 | { |
| 1284 | Target_i386::Relocate::check_range(relinfo, relnum, rel, |
| 1285 | view_size, -2); |
| 1286 | |
| 1287 | unsigned char op2 = view[-2]; |
| 1288 | if (op2 == 0x8b) |
| 1289 | { |
| 1290 | // movl XX,%reg ==> movl $YY,%reg |
| 1291 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1292 | (op1 & 0xc7) == 0x05); |
| 1293 | view[-2] = 0xc7; |
| 1294 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 1295 | } |
| 1296 | else if (op2 == 0x03) |
| 1297 | { |
| 1298 | // addl XX,%reg ==> addl $YY,%reg |
| 1299 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1300 | (op1 & 0xc7) == 0x05); |
| 1301 | view[-2] = 0x81; |
| 1302 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 1303 | } |
| 1304 | else |
| 1305 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0); |
| 1306 | } |
| 1307 | } |
| 1308 | else |
| 1309 | { |
| 1310 | // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| 1311 | // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| 1312 | // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| 1313 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2); |
| 1314 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4); |
| 1315 | |
| 1316 | unsigned char op1 = view[-1]; |
| 1317 | unsigned char op2 = view[-2]; |
| 1318 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1319 | (op1 & 0xc0) == 0x80 && (op1 & 7) != 4); |
| 1320 | if (op2 == 0x8b) |
| 1321 | { |
| 1322 | // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| 1323 | view[-2] = 0xc7; |
| 1324 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 1325 | } |
| 1326 | else if (op2 == 0x2b) |
| 1327 | { |
| 1328 | // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| 1329 | view[-2] = 0x81; |
| 1330 | view[-1] = 0xe8 | ((op1 >> 3) & 7); |
| 1331 | } |
| 1332 | else if (op2 == 0x03) |
| 1333 | { |
| 1334 | // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| 1335 | view[-2] = 0x81; |
| 1336 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 1337 | } |
| 1338 | else |
| 1339 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0); |
| 1340 | } |
| 1341 | |
| 1342 | value = tls_segment->vaddr() + tls_segment->memsz() - value; |
| 1343 | if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE) |
| 1344 | value = - value; |
| 1345 | |
| 1346 | Relocate_functions<32, false>::rel32(view, value); |
| 1347 | } |
| 1348 | |
| 1349 | // Do a relocation in which we convert a TLS Global-Dynamic to a |
| 1350 | // Local-Exec. |
| 1351 | |
| 1352 | inline void |
| 1353 | Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo, |
| 1354 | size_t relnum, |
| 1355 | Output_segment* tls_segment, |
| 1356 | const elfcpp::Rel<32, false>& rel, |
| 1357 | unsigned int, |
| 1358 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 1359 | unsigned char* view, |
| 1360 | off_t view_size) |
| 1361 | { |
| 1362 | // leal foo(,%reg,1),%eax; call ___tls_get_addr |
| 1363 | // ==> movl %gs,0,%eax; subl $foo@tpoff,%eax |
| 1364 | // leal foo(%reg),%eax; call ___tls_get_addr |
| 1365 | // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| 1366 | |
| 1367 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2); |
| 1368 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 9); |
| 1369 | |
| 1370 | unsigned char op1 = view[-1]; |
| 1371 | unsigned char op2 = view[-2]; |
| 1372 | |
| 1373 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1374 | op2 == 0x8d || op2 == 0x04); |
| 1375 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1376 | view[4] == 0xe8); |
| 1377 | |
| 1378 | int roff = 5; |
| 1379 | |
| 1380 | if (op2 == 0x04) |
| 1381 | { |
| 1382 | Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -3); |
| 1383 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1384 | view[-3] == 0x8d); |
| 1385 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1386 | ((op1 & 0xc7) == 0x05 |
| 1387 | && op1 != (4 << 3))); |
| 1388 | memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 1389 | } |
| 1390 | else |
| 1391 | { |
| 1392 | Target_i386::Relocate::check_tls(relinfo, relnum, rel, |
| 1393 | (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| 1394 | if (rel.get_r_offset() + 9 < view_size && view[9] == 0x90) |
| 1395 | { |
| 1396 | // There is a trailing nop. Use the size byte subl. |
| 1397 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 1398 | roff = 6; |
| 1399 | } |
| 1400 | else |
| 1401 | { |
| 1402 | // Use the five byte subl. |
| 1403 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| 1404 | } |
| 1405 | } |
| 1406 | |
| 1407 | value = tls_segment->vaddr() + tls_segment->memsz() - value; |
| 1408 | Relocate_functions<32, false>::rel32(view + roff, value); |
| 1409 | |
| 1410 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 1411 | // We can skip it. |
| 1412 | this->skip_call_tls_get_addr_ = true; |
| 1413 | } |
| 1414 | |
| 1415 | // Check the range for a TLS relocation. |
| 1416 | |
| 1417 | inline void |
| 1418 | Target_i386::Relocate::check_range(const Relocate_info<32, false>* relinfo, |
| 1419 | size_t relnum, |
| 1420 | const elfcpp::Rel<32, false>& rel, |
| 1421 | off_t view_size, off_t off) |
| 1422 | { |
| 1423 | off_t offset = rel.get_r_offset() + off; |
| 1424 | if (offset < 0 || offset > view_size) |
| 1425 | { |
| 1426 | fprintf(stderr, _("%s: %s: TLS relocation out of range\n"), |
| 1427 | program_name, |
| 1428 | relinfo->location(relnum, rel.get_r_offset()).c_str()); |
| 1429 | gold_exit(false); |
| 1430 | } |
| 1431 | } |
| 1432 | |
| 1433 | // Check the validity of a TLS relocation. This is like assert. |
| 1434 | |
| 1435 | inline void |
| 1436 | Target_i386::Relocate::check_tls(const Relocate_info<32, false>* relinfo, |
| 1437 | size_t relnum, |
| 1438 | const elfcpp::Rel<32, false>& rel, |
| 1439 | bool valid) |
| 1440 | { |
| 1441 | if (!valid) |
| 1442 | { |
| 1443 | fprintf(stderr, |
| 1444 | _("%s: %s: TLS relocation against invalid instruction\n"), |
| 1445 | program_name, |
| 1446 | relinfo->location(relnum, rel.get_r_offset()).c_str()); |
| 1447 | gold_exit(false); |
| 1448 | } |
| 1449 | } |
| 1450 | |
| 1451 | // Relocate section data. |
| 1452 | |
| 1453 | void |
| 1454 | Target_i386::relocate_section(const Relocate_info<32, false>* relinfo, |
| 1455 | unsigned int sh_type, |
| 1456 | const unsigned char* prelocs, |
| 1457 | size_t reloc_count, |
| 1458 | unsigned char* view, |
| 1459 | elfcpp::Elf_types<32>::Elf_Addr address, |
| 1460 | off_t view_size) |
| 1461 | { |
| 1462 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 1463 | |
| 1464 | gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL, |
| 1465 | Target_i386::Relocate>( |
| 1466 | relinfo, |
| 1467 | this, |
| 1468 | prelocs, |
| 1469 | reloc_count, |
| 1470 | view, |
| 1471 | address, |
| 1472 | view_size); |
| 1473 | } |
| 1474 | |
| 1475 | // The selector for i386 object files. |
| 1476 | |
| 1477 | class Target_selector_i386 : public Target_selector |
| 1478 | { |
| 1479 | public: |
| 1480 | Target_selector_i386() |
| 1481 | : Target_selector(elfcpp::EM_386, 32, false) |
| 1482 | { } |
| 1483 | |
| 1484 | Target* |
| 1485 | recognize(int machine, int osabi, int abiversion); |
| 1486 | |
| 1487 | private: |
| 1488 | Target_i386* target_; |
| 1489 | }; |
| 1490 | |
| 1491 | // Recognize an i386 object file when we already know that the machine |
| 1492 | // number is EM_386. |
| 1493 | |
| 1494 | Target* |
| 1495 | Target_selector_i386::recognize(int, int, int) |
| 1496 | { |
| 1497 | if (this->target_ == NULL) |
| 1498 | this->target_ = new Target_i386(); |
| 1499 | return this->target_; |
| 1500 | } |
| 1501 | |
| 1502 | Target_selector_i386 target_selector_i386; |
| 1503 | |
| 1504 | } // End anonymous namespace. |