| 1 | // i386.cc -- i386 target support for gold. |
| 2 | |
| 3 | // Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 |
| 4 | // Free Software Foundation, Inc. |
| 5 | // Written by Ian Lance Taylor <iant@google.com>. |
| 6 | |
| 7 | // This file is part of gold. |
| 8 | |
| 9 | // This program is free software; you can redistribute it and/or modify |
| 10 | // it under the terms of the GNU General Public License as published by |
| 11 | // the Free Software Foundation; either version 3 of the License, or |
| 12 | // (at your option) any later version. |
| 13 | |
| 14 | // This program is distributed in the hope that it will be useful, |
| 15 | // but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | // GNU General Public License for more details. |
| 18 | |
| 19 | // You should have received a copy of the GNU General Public License |
| 20 | // along with this program; if not, write to the Free Software |
| 21 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 22 | // MA 02110-1301, USA. |
| 23 | |
| 24 | #include "gold.h" |
| 25 | |
| 26 | #include <cstring> |
| 27 | |
| 28 | #include "elfcpp.h" |
| 29 | #include "dwarf.h" |
| 30 | #include "parameters.h" |
| 31 | #include "reloc.h" |
| 32 | #include "i386.h" |
| 33 | #include "object.h" |
| 34 | #include "symtab.h" |
| 35 | #include "layout.h" |
| 36 | #include "output.h" |
| 37 | #include "copy-relocs.h" |
| 38 | #include "target.h" |
| 39 | #include "target-reloc.h" |
| 40 | #include "target-select.h" |
| 41 | #include "tls.h" |
| 42 | #include "freebsd.h" |
| 43 | #include "nacl.h" |
| 44 | #include "gc.h" |
| 45 | |
| 46 | namespace |
| 47 | { |
| 48 | |
| 49 | using namespace gold; |
| 50 | |
| 51 | // A class to handle the PLT data. |
| 52 | // This is an abstract base class that handles most of the linker details |
| 53 | // but does not know the actual contents of PLT entries. The derived |
| 54 | // classes below fill in those details. |
| 55 | |
| 56 | class Output_data_plt_i386 : public Output_section_data |
| 57 | { |
| 58 | public: |
| 59 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| 60 | |
| 61 | Output_data_plt_i386(Layout*, uint64_t addralign, |
| 62 | Output_data_space*, Output_data_space*); |
| 63 | |
| 64 | // Add an entry to the PLT. |
| 65 | void |
| 66 | add_entry(Symbol_table*, Layout*, Symbol* gsym); |
| 67 | |
| 68 | // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. |
| 69 | unsigned int |
| 70 | add_local_ifunc_entry(Symbol_table*, Layout*, |
| 71 | Sized_relobj_file<32, false>* relobj, |
| 72 | unsigned int local_sym_index); |
| 73 | |
| 74 | // Return the .rel.plt section data. |
| 75 | Reloc_section* |
| 76 | rel_plt() const |
| 77 | { return this->rel_; } |
| 78 | |
| 79 | // Return where the TLS_DESC relocations should go. |
| 80 | Reloc_section* |
| 81 | rel_tls_desc(Layout*); |
| 82 | |
| 83 | // Return where the IRELATIVE relocations should go. |
| 84 | Reloc_section* |
| 85 | rel_irelative(Symbol_table*, Layout*); |
| 86 | |
| 87 | // Return whether we created a section for IRELATIVE relocations. |
| 88 | bool |
| 89 | has_irelative_section() const |
| 90 | { return this->irelative_rel_ != NULL; } |
| 91 | |
| 92 | // Return the number of PLT entries. |
| 93 | unsigned int |
| 94 | entry_count() const |
| 95 | { return this->count_ + this->irelative_count_; } |
| 96 | |
| 97 | // Return the offset of the first non-reserved PLT entry. |
| 98 | unsigned int |
| 99 | first_plt_entry_offset() |
| 100 | { return this->get_plt_entry_size(); } |
| 101 | |
| 102 | // Return the size of a PLT entry. |
| 103 | unsigned int |
| 104 | get_plt_entry_size() const |
| 105 | { return this->do_get_plt_entry_size(); } |
| 106 | |
| 107 | // Return the PLT address to use for a global symbol. |
| 108 | uint64_t |
| 109 | address_for_global(const Symbol*); |
| 110 | |
| 111 | // Return the PLT address to use for a local symbol. |
| 112 | uint64_t |
| 113 | address_for_local(const Relobj*, unsigned int symndx); |
| 114 | |
| 115 | // Add .eh_frame information for the PLT. |
| 116 | void |
| 117 | add_eh_frame(Layout* layout) |
| 118 | { this->do_add_eh_frame(layout); } |
| 119 | |
| 120 | protected: |
| 121 | // Fill the first PLT entry, given the pointer to the PLT section data |
| 122 | // and the runtime address of the GOT. |
| 123 | void |
| 124 | fill_first_plt_entry(unsigned char* pov, |
| 125 | elfcpp::Elf_types<32>::Elf_Addr got_address) |
| 126 | { this->do_fill_first_plt_entry(pov, got_address); } |
| 127 | |
| 128 | // Fill a normal PLT entry, given the pointer to the entry's data in the |
| 129 | // section, the runtime address of the GOT, the offset into the GOT of |
| 130 | // the corresponding slot, the offset into the relocation section of the |
| 131 | // corresponding reloc, and the offset of this entry within the whole |
| 132 | // PLT. Return the offset from this PLT entry's runtime address that |
| 133 | // should be used to compute the initial value of the GOT slot. |
| 134 | unsigned int |
| 135 | fill_plt_entry(unsigned char* pov, |
| 136 | elfcpp::Elf_types<32>::Elf_Addr got_address, |
| 137 | unsigned int got_offset, |
| 138 | unsigned int plt_offset, |
| 139 | unsigned int plt_rel_offset) |
| 140 | { |
| 141 | return this->do_fill_plt_entry(pov, got_address, got_offset, |
| 142 | plt_offset, plt_rel_offset); |
| 143 | } |
| 144 | |
| 145 | virtual unsigned int |
| 146 | do_get_plt_entry_size() const = 0; |
| 147 | |
| 148 | virtual void |
| 149 | do_fill_first_plt_entry(unsigned char* pov, |
| 150 | elfcpp::Elf_types<32>::Elf_Addr got_address) = 0; |
| 151 | |
| 152 | virtual unsigned int |
| 153 | do_fill_plt_entry(unsigned char* pov, |
| 154 | elfcpp::Elf_types<32>::Elf_Addr got_address, |
| 155 | unsigned int got_offset, |
| 156 | unsigned int plt_offset, |
| 157 | unsigned int plt_rel_offset) = 0; |
| 158 | |
| 159 | virtual void |
| 160 | do_add_eh_frame(Layout*) = 0; |
| 161 | |
| 162 | void |
| 163 | do_adjust_output_section(Output_section* os); |
| 164 | |
| 165 | // Write to a map file. |
| 166 | void |
| 167 | do_print_to_mapfile(Mapfile* mapfile) const |
| 168 | { mapfile->print_output_data(this, _("** PLT")); } |
| 169 | |
| 170 | // The .eh_frame unwind information for the PLT. |
| 171 | // The CIE is common across variants of the PLT format. |
| 172 | static const int plt_eh_frame_cie_size = 16; |
| 173 | static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size]; |
| 174 | |
| 175 | private: |
| 176 | // Set the final size. |
| 177 | void |
| 178 | set_final_data_size() |
| 179 | { |
| 180 | this->set_data_size((this->count_ + this->irelative_count_ + 1) |
| 181 | * this->get_plt_entry_size()); |
| 182 | } |
| 183 | |
| 184 | // Write out the PLT data. |
| 185 | void |
| 186 | do_write(Output_file*); |
| 187 | |
| 188 | // We keep a list of global STT_GNU_IFUNC symbols, each with its |
| 189 | // offset in the GOT. |
| 190 | struct Global_ifunc |
| 191 | { |
| 192 | Symbol* sym; |
| 193 | unsigned int got_offset; |
| 194 | }; |
| 195 | |
| 196 | // We keep a list of local STT_GNU_IFUNC symbols, each with its |
| 197 | // offset in the GOT. |
| 198 | struct Local_ifunc |
| 199 | { |
| 200 | Sized_relobj_file<32, false>* object; |
| 201 | unsigned int local_sym_index; |
| 202 | unsigned int got_offset; |
| 203 | }; |
| 204 | |
| 205 | // A pointer to the Layout class, so that we can find the .dynamic |
| 206 | // section when we write out the GOT PLT section. |
| 207 | Layout* layout_; |
| 208 | // The reloc section. |
| 209 | Reloc_section* rel_; |
| 210 | // The TLS_DESC relocations, if necessary. These must follow the |
| 211 | // regular PLT relocs. |
| 212 | Reloc_section* tls_desc_rel_; |
| 213 | // The IRELATIVE relocations, if necessary. These must follow the |
| 214 | // regular relocatoins and the TLS_DESC relocations. |
| 215 | Reloc_section* irelative_rel_; |
| 216 | // The .got.plt section. |
| 217 | Output_data_space* got_plt_; |
| 218 | // The part of the .got.plt section used for IRELATIVE relocs. |
| 219 | Output_data_space* got_irelative_; |
| 220 | // The number of PLT entries. |
| 221 | unsigned int count_; |
| 222 | // Number of PLT entries with R_386_IRELATIVE relocs. These follow |
| 223 | // the regular PLT entries. |
| 224 | unsigned int irelative_count_; |
| 225 | // Global STT_GNU_IFUNC symbols. |
| 226 | std::vector<Global_ifunc> global_ifuncs_; |
| 227 | // Local STT_GNU_IFUNC symbols. |
| 228 | std::vector<Local_ifunc> local_ifuncs_; |
| 229 | }; |
| 230 | |
| 231 | // This is an abstract class for the standard PLT layout. |
| 232 | // The derived classes below handle the actual PLT contents |
| 233 | // for the executable (non-PIC) and shared-library (PIC) cases. |
| 234 | // The unwind information is uniform across those two, so it's here. |
| 235 | |
| 236 | class Output_data_plt_i386_standard : public Output_data_plt_i386 |
| 237 | { |
| 238 | public: |
| 239 | Output_data_plt_i386_standard(Layout* layout, |
| 240 | Output_data_space* got_plt, |
| 241 | Output_data_space* got_irelative) |
| 242 | : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative) |
| 243 | { } |
| 244 | |
| 245 | protected: |
| 246 | virtual unsigned int |
| 247 | do_get_plt_entry_size() const |
| 248 | { return plt_entry_size; } |
| 249 | |
| 250 | virtual void |
| 251 | do_add_eh_frame(Layout* layout) |
| 252 | { |
| 253 | layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size, |
| 254 | plt_eh_frame_fde, plt_eh_frame_fde_size); |
| 255 | } |
| 256 | |
| 257 | // The size of an entry in the PLT. |
| 258 | static const int plt_entry_size = 16; |
| 259 | |
| 260 | // The .eh_frame unwind information for the PLT. |
| 261 | static const int plt_eh_frame_fde_size = 32; |
| 262 | static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; |
| 263 | }; |
| 264 | |
| 265 | // Actually fill the PLT contents for an executable (non-PIC). |
| 266 | |
| 267 | class Output_data_plt_i386_exec : public Output_data_plt_i386_standard |
| 268 | { |
| 269 | public: |
| 270 | Output_data_plt_i386_exec(Layout* layout, |
| 271 | Output_data_space* got_plt, |
| 272 | Output_data_space* got_irelative) |
| 273 | : Output_data_plt_i386_standard(layout, got_plt, got_irelative) |
| 274 | { } |
| 275 | |
| 276 | protected: |
| 277 | virtual void |
| 278 | do_fill_first_plt_entry(unsigned char* pov, |
| 279 | elfcpp::Elf_types<32>::Elf_Addr got_address); |
| 280 | |
| 281 | virtual unsigned int |
| 282 | do_fill_plt_entry(unsigned char* pov, |
| 283 | elfcpp::Elf_types<32>::Elf_Addr got_address, |
| 284 | unsigned int got_offset, |
| 285 | unsigned int plt_offset, |
| 286 | unsigned int plt_rel_offset); |
| 287 | |
| 288 | private: |
| 289 | // The first entry in the PLT for an executable. |
| 290 | static const unsigned char first_plt_entry[plt_entry_size]; |
| 291 | |
| 292 | // Other entries in the PLT for an executable. |
| 293 | static const unsigned char plt_entry[plt_entry_size]; |
| 294 | }; |
| 295 | |
| 296 | // Actually fill the PLT contents for a shared library (PIC). |
| 297 | |
| 298 | class Output_data_plt_i386_dyn : public Output_data_plt_i386_standard |
| 299 | { |
| 300 | public: |
| 301 | Output_data_plt_i386_dyn(Layout* layout, |
| 302 | Output_data_space* got_plt, |
| 303 | Output_data_space* got_irelative) |
| 304 | : Output_data_plt_i386_standard(layout, got_plt, got_irelative) |
| 305 | { } |
| 306 | |
| 307 | protected: |
| 308 | virtual void |
| 309 | do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr); |
| 310 | |
| 311 | virtual unsigned int |
| 312 | do_fill_plt_entry(unsigned char* pov, |
| 313 | elfcpp::Elf_types<32>::Elf_Addr, |
| 314 | unsigned int got_offset, |
| 315 | unsigned int plt_offset, |
| 316 | unsigned int plt_rel_offset); |
| 317 | |
| 318 | private: |
| 319 | // The first entry in the PLT for a shared object. |
| 320 | static const unsigned char first_plt_entry[plt_entry_size]; |
| 321 | |
| 322 | // Other entries in the PLT for a shared object. |
| 323 | static const unsigned char plt_entry[plt_entry_size]; |
| 324 | }; |
| 325 | |
| 326 | // The i386 target class. |
| 327 | // TLS info comes from |
| 328 | // http://people.redhat.com/drepper/tls.pdf |
| 329 | // http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt |
| 330 | |
| 331 | class Target_i386 : public Sized_target<32, false> |
| 332 | { |
| 333 | public: |
| 334 | typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section; |
| 335 | |
| 336 | Target_i386(const Target::Target_info* info = &i386_info) |
| 337 | : Sized_target<32, false>(info), |
| 338 | got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL), |
| 339 | got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL), |
| 340 | rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY), |
| 341 | got_mod_index_offset_(-1U), tls_base_symbol_defined_(false) |
| 342 | { } |
| 343 | |
| 344 | // Process the relocations to determine unreferenced sections for |
| 345 | // garbage collection. |
| 346 | void |
| 347 | gc_process_relocs(Symbol_table* symtab, |
| 348 | Layout* layout, |
| 349 | Sized_relobj_file<32, false>* object, |
| 350 | unsigned int data_shndx, |
| 351 | unsigned int sh_type, |
| 352 | const unsigned char* prelocs, |
| 353 | size_t reloc_count, |
| 354 | Output_section* output_section, |
| 355 | bool needs_special_offset_handling, |
| 356 | size_t local_symbol_count, |
| 357 | const unsigned char* plocal_symbols); |
| 358 | |
| 359 | // Scan the relocations to look for symbol adjustments. |
| 360 | void |
| 361 | scan_relocs(Symbol_table* symtab, |
| 362 | Layout* layout, |
| 363 | Sized_relobj_file<32, false>* object, |
| 364 | unsigned int data_shndx, |
| 365 | unsigned int sh_type, |
| 366 | const unsigned char* prelocs, |
| 367 | size_t reloc_count, |
| 368 | Output_section* output_section, |
| 369 | bool needs_special_offset_handling, |
| 370 | size_t local_symbol_count, |
| 371 | const unsigned char* plocal_symbols); |
| 372 | |
| 373 | // Finalize the sections. |
| 374 | void |
| 375 | do_finalize_sections(Layout*, const Input_objects*, Symbol_table*); |
| 376 | |
| 377 | // Return the value to use for a dynamic which requires special |
| 378 | // treatment. |
| 379 | uint64_t |
| 380 | do_dynsym_value(const Symbol*) const; |
| 381 | |
| 382 | // Relocate a section. |
| 383 | void |
| 384 | relocate_section(const Relocate_info<32, false>*, |
| 385 | unsigned int sh_type, |
| 386 | const unsigned char* prelocs, |
| 387 | size_t reloc_count, |
| 388 | Output_section* output_section, |
| 389 | bool needs_special_offset_handling, |
| 390 | unsigned char* view, |
| 391 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 392 | section_size_type view_size, |
| 393 | const Reloc_symbol_changes*); |
| 394 | |
| 395 | // Scan the relocs during a relocatable link. |
| 396 | void |
| 397 | scan_relocatable_relocs(Symbol_table* symtab, |
| 398 | Layout* layout, |
| 399 | Sized_relobj_file<32, false>* object, |
| 400 | unsigned int data_shndx, |
| 401 | unsigned int sh_type, |
| 402 | const unsigned char* prelocs, |
| 403 | size_t reloc_count, |
| 404 | Output_section* output_section, |
| 405 | bool needs_special_offset_handling, |
| 406 | size_t local_symbol_count, |
| 407 | const unsigned char* plocal_symbols, |
| 408 | Relocatable_relocs*); |
| 409 | |
| 410 | // Emit relocations for a section. |
| 411 | void |
| 412 | relocate_relocs(const Relocate_info<32, false>*, |
| 413 | unsigned int sh_type, |
| 414 | const unsigned char* prelocs, |
| 415 | size_t reloc_count, |
| 416 | Output_section* output_section, |
| 417 | elfcpp::Elf_types<32>::Elf_Off offset_in_output_section, |
| 418 | const Relocatable_relocs*, |
| 419 | unsigned char* view, |
| 420 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 421 | section_size_type view_size, |
| 422 | unsigned char* reloc_view, |
| 423 | section_size_type reloc_view_size); |
| 424 | |
| 425 | // Return a string used to fill a code section with nops. |
| 426 | std::string |
| 427 | do_code_fill(section_size_type length) const; |
| 428 | |
| 429 | // Return whether SYM is defined by the ABI. |
| 430 | bool |
| 431 | do_is_defined_by_abi(const Symbol* sym) const |
| 432 | { return strcmp(sym->name(), "___tls_get_addr") == 0; } |
| 433 | |
| 434 | // Return whether a symbol name implies a local label. The UnixWare |
| 435 | // 2.1 cc generates temporary symbols that start with .X, so we |
| 436 | // recognize them here. FIXME: do other SVR4 compilers also use .X?. |
| 437 | // If so, we should move the .X recognition into |
| 438 | // Target::do_is_local_label_name. |
| 439 | bool |
| 440 | do_is_local_label_name(const char* name) const |
| 441 | { |
| 442 | if (name[0] == '.' && name[1] == 'X') |
| 443 | return true; |
| 444 | return Target::do_is_local_label_name(name); |
| 445 | } |
| 446 | |
| 447 | // Return the PLT address to use for a global symbol. |
| 448 | uint64_t |
| 449 | do_plt_address_for_global(const Symbol* gsym) const |
| 450 | { return this->plt_section()->address_for_global(gsym); } |
| 451 | |
| 452 | uint64_t |
| 453 | do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const |
| 454 | { return this->plt_section()->address_for_local(relobj, symndx); } |
| 455 | |
| 456 | // We can tell whether we take the address of a function. |
| 457 | inline bool |
| 458 | do_can_check_for_function_pointers() const |
| 459 | { return true; } |
| 460 | |
| 461 | // Return the base for a DW_EH_PE_datarel encoding. |
| 462 | uint64_t |
| 463 | do_ehframe_datarel_base() const; |
| 464 | |
| 465 | // Return whether SYM is call to a non-split function. |
| 466 | bool |
| 467 | do_is_call_to_non_split(const Symbol* sym, unsigned int) const; |
| 468 | |
| 469 | // Adjust -fsplit-stack code which calls non-split-stack code. |
| 470 | void |
| 471 | do_calls_non_split(Relobj* object, unsigned int shndx, |
| 472 | section_offset_type fnoffset, section_size_type fnsize, |
| 473 | unsigned char* view, section_size_type view_size, |
| 474 | std::string* from, std::string* to) const; |
| 475 | |
| 476 | // Return the size of the GOT section. |
| 477 | section_size_type |
| 478 | got_size() const |
| 479 | { |
| 480 | gold_assert(this->got_ != NULL); |
| 481 | return this->got_->data_size(); |
| 482 | } |
| 483 | |
| 484 | // Return the number of entries in the GOT. |
| 485 | unsigned int |
| 486 | got_entry_count() const |
| 487 | { |
| 488 | if (this->got_ == NULL) |
| 489 | return 0; |
| 490 | return this->got_size() / 4; |
| 491 | } |
| 492 | |
| 493 | // Return the number of entries in the PLT. |
| 494 | unsigned int |
| 495 | plt_entry_count() const; |
| 496 | |
| 497 | // Return the offset of the first non-reserved PLT entry. |
| 498 | unsigned int |
| 499 | first_plt_entry_offset() const; |
| 500 | |
| 501 | // Return the size of each PLT entry. |
| 502 | unsigned int |
| 503 | plt_entry_size() const; |
| 504 | |
| 505 | protected: |
| 506 | // Instantiate the plt_ member. |
| 507 | // This chooses the right PLT flavor for an executable or a shared object. |
| 508 | Output_data_plt_i386* |
| 509 | make_data_plt(Layout* layout, |
| 510 | Output_data_space* got_plt, |
| 511 | Output_data_space* got_irelative, |
| 512 | bool dyn) |
| 513 | { return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); } |
| 514 | |
| 515 | virtual Output_data_plt_i386* |
| 516 | do_make_data_plt(Layout* layout, |
| 517 | Output_data_space* got_plt, |
| 518 | Output_data_space* got_irelative, |
| 519 | bool dyn) |
| 520 | { |
| 521 | if (dyn) |
| 522 | return new Output_data_plt_i386_dyn(layout, got_plt, got_irelative); |
| 523 | else |
| 524 | return new Output_data_plt_i386_exec(layout, got_plt, got_irelative); |
| 525 | } |
| 526 | |
| 527 | private: |
| 528 | // The class which scans relocations. |
| 529 | struct Scan |
| 530 | { |
| 531 | static inline int |
| 532 | |
| 533 | get_reference_flags(unsigned int r_type); |
| 534 | |
| 535 | inline void |
| 536 | local(Symbol_table* symtab, Layout* layout, Target_i386* target, |
| 537 | Sized_relobj_file<32, false>* object, |
| 538 | unsigned int data_shndx, |
| 539 | Output_section* output_section, |
| 540 | const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| 541 | const elfcpp::Sym<32, false>& lsym, |
| 542 | bool is_discarded); |
| 543 | |
| 544 | inline void |
| 545 | global(Symbol_table* symtab, Layout* layout, Target_i386* target, |
| 546 | Sized_relobj_file<32, false>* object, |
| 547 | unsigned int data_shndx, |
| 548 | Output_section* output_section, |
| 549 | const elfcpp::Rel<32, false>& reloc, unsigned int r_type, |
| 550 | Symbol* gsym); |
| 551 | |
| 552 | inline bool |
| 553 | local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| 554 | Target_i386* target, |
| 555 | Sized_relobj_file<32, false>* object, |
| 556 | unsigned int data_shndx, |
| 557 | Output_section* output_section, |
| 558 | const elfcpp::Rel<32, false>& reloc, |
| 559 | unsigned int r_type, |
| 560 | const elfcpp::Sym<32, false>& lsym); |
| 561 | |
| 562 | inline bool |
| 563 | global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout, |
| 564 | Target_i386* target, |
| 565 | Sized_relobj_file<32, false>* object, |
| 566 | unsigned int data_shndx, |
| 567 | Output_section* output_section, |
| 568 | const elfcpp::Rel<32, false>& reloc, |
| 569 | unsigned int r_type, |
| 570 | Symbol* gsym); |
| 571 | |
| 572 | inline bool |
| 573 | possible_function_pointer_reloc(unsigned int r_type); |
| 574 | |
| 575 | bool |
| 576 | reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*, |
| 577 | unsigned int r_type); |
| 578 | |
| 579 | static void |
| 580 | unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type); |
| 581 | |
| 582 | static void |
| 583 | unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type, |
| 584 | Symbol*); |
| 585 | }; |
| 586 | |
| 587 | // The class which implements relocation. |
| 588 | class Relocate |
| 589 | { |
| 590 | public: |
| 591 | Relocate() |
| 592 | : skip_call_tls_get_addr_(false), |
| 593 | local_dynamic_type_(LOCAL_DYNAMIC_NONE) |
| 594 | { } |
| 595 | |
| 596 | ~Relocate() |
| 597 | { |
| 598 | if (this->skip_call_tls_get_addr_) |
| 599 | { |
| 600 | // FIXME: This needs to specify the location somehow. |
| 601 | gold_error(_("missing expected TLS relocation")); |
| 602 | } |
| 603 | } |
| 604 | |
| 605 | // Return whether the static relocation needs to be applied. |
| 606 | inline bool |
| 607 | should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| 608 | unsigned int r_type, |
| 609 | bool is_32bit, |
| 610 | Output_section* output_section); |
| 611 | |
| 612 | // Do a relocation. Return false if the caller should not issue |
| 613 | // any warnings about this relocation. |
| 614 | inline bool |
| 615 | relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*, |
| 616 | size_t relnum, const elfcpp::Rel<32, false>&, |
| 617 | unsigned int r_type, const Sized_symbol<32>*, |
| 618 | const Symbol_value<32>*, |
| 619 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| 620 | section_size_type); |
| 621 | |
| 622 | private: |
| 623 | // Do a TLS relocation. |
| 624 | inline void |
| 625 | relocate_tls(const Relocate_info<32, false>*, Target_i386* target, |
| 626 | size_t relnum, const elfcpp::Rel<32, false>&, |
| 627 | unsigned int r_type, const Sized_symbol<32>*, |
| 628 | const Symbol_value<32>*, |
| 629 | unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, |
| 630 | section_size_type); |
| 631 | |
| 632 | // Do a TLS General-Dynamic to Initial-Exec transition. |
| 633 | inline void |
| 634 | tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| 635 | Output_segment* tls_segment, |
| 636 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 637 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 638 | unsigned char* view, |
| 639 | section_size_type view_size); |
| 640 | |
| 641 | // Do a TLS General-Dynamic to Local-Exec transition. |
| 642 | inline void |
| 643 | tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 644 | Output_segment* tls_segment, |
| 645 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 646 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 647 | unsigned char* view, |
| 648 | section_size_type view_size); |
| 649 | |
| 650 | // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec |
| 651 | // transition. |
| 652 | inline void |
| 653 | tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum, |
| 654 | Output_segment* tls_segment, |
| 655 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 656 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 657 | unsigned char* view, |
| 658 | section_size_type view_size); |
| 659 | |
| 660 | // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec |
| 661 | // transition. |
| 662 | inline void |
| 663 | tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 664 | Output_segment* tls_segment, |
| 665 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 666 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 667 | unsigned char* view, |
| 668 | section_size_type view_size); |
| 669 | |
| 670 | // Do a TLS Local-Dynamic to Local-Exec transition. |
| 671 | inline void |
| 672 | tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 673 | Output_segment* tls_segment, |
| 674 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 675 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 676 | unsigned char* view, |
| 677 | section_size_type view_size); |
| 678 | |
| 679 | // Do a TLS Initial-Exec to Local-Exec transition. |
| 680 | static inline void |
| 681 | tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum, |
| 682 | Output_segment* tls_segment, |
| 683 | const elfcpp::Rel<32, false>&, unsigned int r_type, |
| 684 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 685 | unsigned char* view, |
| 686 | section_size_type view_size); |
| 687 | |
| 688 | // We need to keep track of which type of local dynamic relocation |
| 689 | // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly. |
| 690 | enum Local_dynamic_type |
| 691 | { |
| 692 | LOCAL_DYNAMIC_NONE, |
| 693 | LOCAL_DYNAMIC_SUN, |
| 694 | LOCAL_DYNAMIC_GNU |
| 695 | }; |
| 696 | |
| 697 | // This is set if we should skip the next reloc, which should be a |
| 698 | // PLT32 reloc against ___tls_get_addr. |
| 699 | bool skip_call_tls_get_addr_; |
| 700 | // The type of local dynamic relocation we have seen in the section |
| 701 | // being relocated, if any. |
| 702 | Local_dynamic_type local_dynamic_type_; |
| 703 | }; |
| 704 | |
| 705 | // A class which returns the size required for a relocation type, |
| 706 | // used while scanning relocs during a relocatable link. |
| 707 | class Relocatable_size_for_reloc |
| 708 | { |
| 709 | public: |
| 710 | unsigned int |
| 711 | get_size_for_reloc(unsigned int, Relobj*); |
| 712 | }; |
| 713 | |
| 714 | // Adjust TLS relocation type based on the options and whether this |
| 715 | // is a local symbol. |
| 716 | static tls::Tls_optimization |
| 717 | optimize_tls_reloc(bool is_final, int r_type); |
| 718 | |
| 719 | // Get the GOT section, creating it if necessary. |
| 720 | Output_data_got<32, false>* |
| 721 | got_section(Symbol_table*, Layout*); |
| 722 | |
| 723 | // Get the GOT PLT section. |
| 724 | Output_data_space* |
| 725 | got_plt_section() const |
| 726 | { |
| 727 | gold_assert(this->got_plt_ != NULL); |
| 728 | return this->got_plt_; |
| 729 | } |
| 730 | |
| 731 | // Get the GOT section for TLSDESC entries. |
| 732 | Output_data_got<32, false>* |
| 733 | got_tlsdesc_section() const |
| 734 | { |
| 735 | gold_assert(this->got_tlsdesc_ != NULL); |
| 736 | return this->got_tlsdesc_; |
| 737 | } |
| 738 | |
| 739 | // Create the PLT section. |
| 740 | void |
| 741 | make_plt_section(Symbol_table* symtab, Layout* layout); |
| 742 | |
| 743 | // Create a PLT entry for a global symbol. |
| 744 | void |
| 745 | make_plt_entry(Symbol_table*, Layout*, Symbol*); |
| 746 | |
| 747 | // Create a PLT entry for a local STT_GNU_IFUNC symbol. |
| 748 | void |
| 749 | make_local_ifunc_plt_entry(Symbol_table*, Layout*, |
| 750 | Sized_relobj_file<32, false>* relobj, |
| 751 | unsigned int local_sym_index); |
| 752 | |
| 753 | // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| 754 | void |
| 755 | define_tls_base_symbol(Symbol_table*, Layout*); |
| 756 | |
| 757 | // Create a GOT entry for the TLS module index. |
| 758 | unsigned int |
| 759 | got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| 760 | Sized_relobj_file<32, false>* object); |
| 761 | |
| 762 | // Get the PLT section. |
| 763 | Output_data_plt_i386* |
| 764 | plt_section() const |
| 765 | { |
| 766 | gold_assert(this->plt_ != NULL); |
| 767 | return this->plt_; |
| 768 | } |
| 769 | |
| 770 | // Get the dynamic reloc section, creating it if necessary. |
| 771 | Reloc_section* |
| 772 | rel_dyn_section(Layout*); |
| 773 | |
| 774 | // Get the section to use for TLS_DESC relocations. |
| 775 | Reloc_section* |
| 776 | rel_tls_desc_section(Layout*) const; |
| 777 | |
| 778 | // Get the section to use for IRELATIVE relocations. |
| 779 | Reloc_section* |
| 780 | rel_irelative_section(Layout*); |
| 781 | |
| 782 | // Add a potential copy relocation. |
| 783 | void |
| 784 | copy_reloc(Symbol_table* symtab, Layout* layout, |
| 785 | Sized_relobj_file<32, false>* object, |
| 786 | unsigned int shndx, Output_section* output_section, |
| 787 | Symbol* sym, const elfcpp::Rel<32, false>& reloc) |
| 788 | { |
| 789 | this->copy_relocs_.copy_reloc(symtab, layout, |
| 790 | symtab->get_sized_symbol<32>(sym), |
| 791 | object, shndx, output_section, reloc, |
| 792 | this->rel_dyn_section(layout)); |
| 793 | } |
| 794 | |
| 795 | // Information about this specific target which we pass to the |
| 796 | // general Target structure. |
| 797 | static const Target::Target_info i386_info; |
| 798 | |
| 799 | // The types of GOT entries needed for this platform. |
| 800 | // These values are exposed to the ABI in an incremental link. |
| 801 | // Do not renumber existing values without changing the version |
| 802 | // number of the .gnu_incremental_inputs section. |
| 803 | enum Got_type |
| 804 | { |
| 805 | GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol |
| 806 | GOT_TYPE_TLS_NOFFSET = 1, // GOT entry for negative TLS offset |
| 807 | GOT_TYPE_TLS_OFFSET = 2, // GOT entry for positive TLS offset |
| 808 | GOT_TYPE_TLS_PAIR = 3, // GOT entry for TLS module/offset pair |
| 809 | GOT_TYPE_TLS_DESC = 4 // GOT entry for TLS_DESC pair |
| 810 | }; |
| 811 | |
| 812 | // The GOT section. |
| 813 | Output_data_got<32, false>* got_; |
| 814 | // The PLT section. |
| 815 | Output_data_plt_i386* plt_; |
| 816 | // The GOT PLT section. |
| 817 | Output_data_space* got_plt_; |
| 818 | // The GOT section for IRELATIVE relocations. |
| 819 | Output_data_space* got_irelative_; |
| 820 | // The GOT section for TLSDESC relocations. |
| 821 | Output_data_got<32, false>* got_tlsdesc_; |
| 822 | // The _GLOBAL_OFFSET_TABLE_ symbol. |
| 823 | Symbol* global_offset_table_; |
| 824 | // The dynamic reloc section. |
| 825 | Reloc_section* rel_dyn_; |
| 826 | // The section to use for IRELATIVE relocs. |
| 827 | Reloc_section* rel_irelative_; |
| 828 | // Relocs saved to avoid a COPY reloc. |
| 829 | Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_; |
| 830 | // Offset of the GOT entry for the TLS module index. |
| 831 | unsigned int got_mod_index_offset_; |
| 832 | // True if the _TLS_MODULE_BASE_ symbol has been defined. |
| 833 | bool tls_base_symbol_defined_; |
| 834 | }; |
| 835 | |
| 836 | const Target::Target_info Target_i386::i386_info = |
| 837 | { |
| 838 | 32, // size |
| 839 | false, // is_big_endian |
| 840 | elfcpp::EM_386, // machine_code |
| 841 | false, // has_make_symbol |
| 842 | false, // has_resolve |
| 843 | true, // has_code_fill |
| 844 | true, // is_default_stack_executable |
| 845 | true, // can_icf_inline_merge_sections |
| 846 | '\0', // wrap_char |
| 847 | "/usr/lib/libc.so.1", // dynamic_linker |
| 848 | 0x08048000, // default_text_segment_address |
| 849 | 0x1000, // abi_pagesize (overridable by -z max-page-size) |
| 850 | 0x1000, // common_pagesize (overridable by -z common-page-size) |
| 851 | false, // isolate_execinstr |
| 852 | 0, // rosegment_gap |
| 853 | elfcpp::SHN_UNDEF, // small_common_shndx |
| 854 | elfcpp::SHN_UNDEF, // large_common_shndx |
| 855 | 0, // small_common_section_flags |
| 856 | 0, // large_common_section_flags |
| 857 | NULL, // attributes_section |
| 858 | NULL, // attributes_vendor |
| 859 | "_start" // entry_symbol_name |
| 860 | }; |
| 861 | |
| 862 | // Get the GOT section, creating it if necessary. |
| 863 | |
| 864 | Output_data_got<32, false>* |
| 865 | Target_i386::got_section(Symbol_table* symtab, Layout* layout) |
| 866 | { |
| 867 | if (this->got_ == NULL) |
| 868 | { |
| 869 | gold_assert(symtab != NULL && layout != NULL); |
| 870 | |
| 871 | this->got_ = new Output_data_got<32, false>(); |
| 872 | |
| 873 | // When using -z now, we can treat .got.plt as a relro section. |
| 874 | // Without -z now, it is modified after program startup by lazy |
| 875 | // PLT relocations. |
| 876 | bool is_got_plt_relro = parameters->options().now(); |
| 877 | Output_section_order got_order = (is_got_plt_relro |
| 878 | ? ORDER_RELRO |
| 879 | : ORDER_RELRO_LAST); |
| 880 | Output_section_order got_plt_order = (is_got_plt_relro |
| 881 | ? ORDER_RELRO |
| 882 | : ORDER_NON_RELRO_FIRST); |
| 883 | |
| 884 | layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS, |
| 885 | (elfcpp::SHF_ALLOC |
| 886 | | elfcpp::SHF_WRITE), |
| 887 | this->got_, got_order, true); |
| 888 | |
| 889 | this->got_plt_ = new Output_data_space(4, "** GOT PLT"); |
| 890 | layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| 891 | (elfcpp::SHF_ALLOC |
| 892 | | elfcpp::SHF_WRITE), |
| 893 | this->got_plt_, got_plt_order, |
| 894 | is_got_plt_relro); |
| 895 | |
| 896 | // The first three entries are reserved. |
| 897 | this->got_plt_->set_current_data_size(3 * 4); |
| 898 | |
| 899 | if (!is_got_plt_relro) |
| 900 | { |
| 901 | // Those bytes can go into the relro segment. |
| 902 | layout->increase_relro(3 * 4); |
| 903 | } |
| 904 | |
| 905 | // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT. |
| 906 | this->global_offset_table_ = |
| 907 | symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL, |
| 908 | Symbol_table::PREDEFINED, |
| 909 | this->got_plt_, |
| 910 | 0, 0, elfcpp::STT_OBJECT, |
| 911 | elfcpp::STB_LOCAL, |
| 912 | elfcpp::STV_HIDDEN, 0, |
| 913 | false, false); |
| 914 | |
| 915 | // If there are any IRELATIVE relocations, they get GOT entries |
| 916 | // in .got.plt after the jump slot relocations. |
| 917 | this->got_irelative_ = new Output_data_space(4, "** GOT IRELATIVE PLT"); |
| 918 | layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| 919 | (elfcpp::SHF_ALLOC |
| 920 | | elfcpp::SHF_WRITE), |
| 921 | this->got_irelative_, |
| 922 | got_plt_order, is_got_plt_relro); |
| 923 | |
| 924 | // If there are any TLSDESC relocations, they get GOT entries in |
| 925 | // .got.plt after the jump slot entries. |
| 926 | this->got_tlsdesc_ = new Output_data_got<32, false>(); |
| 927 | layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS, |
| 928 | (elfcpp::SHF_ALLOC |
| 929 | | elfcpp::SHF_WRITE), |
| 930 | this->got_tlsdesc_, |
| 931 | got_plt_order, is_got_plt_relro); |
| 932 | } |
| 933 | |
| 934 | return this->got_; |
| 935 | } |
| 936 | |
| 937 | // Get the dynamic reloc section, creating it if necessary. |
| 938 | |
| 939 | Target_i386::Reloc_section* |
| 940 | Target_i386::rel_dyn_section(Layout* layout) |
| 941 | { |
| 942 | if (this->rel_dyn_ == NULL) |
| 943 | { |
| 944 | gold_assert(layout != NULL); |
| 945 | this->rel_dyn_ = new Reloc_section(parameters->options().combreloc()); |
| 946 | layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| 947 | elfcpp::SHF_ALLOC, this->rel_dyn_, |
| 948 | ORDER_DYNAMIC_RELOCS, false); |
| 949 | } |
| 950 | return this->rel_dyn_; |
| 951 | } |
| 952 | |
| 953 | // Get the section to use for IRELATIVE relocs, creating it if |
| 954 | // necessary. These go in .rel.dyn, but only after all other dynamic |
| 955 | // relocations. They need to follow the other dynamic relocations so |
| 956 | // that they can refer to global variables initialized by those |
| 957 | // relocs. |
| 958 | |
| 959 | Target_i386::Reloc_section* |
| 960 | Target_i386::rel_irelative_section(Layout* layout) |
| 961 | { |
| 962 | if (this->rel_irelative_ == NULL) |
| 963 | { |
| 964 | // Make sure we have already create the dynamic reloc section. |
| 965 | this->rel_dyn_section(layout); |
| 966 | this->rel_irelative_ = new Reloc_section(false); |
| 967 | layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL, |
| 968 | elfcpp::SHF_ALLOC, this->rel_irelative_, |
| 969 | ORDER_DYNAMIC_RELOCS, false); |
| 970 | gold_assert(this->rel_dyn_->output_section() |
| 971 | == this->rel_irelative_->output_section()); |
| 972 | } |
| 973 | return this->rel_irelative_; |
| 974 | } |
| 975 | |
| 976 | // Create the PLT section. The ordinary .got section is an argument, |
| 977 | // since we need to refer to the start. We also create our own .got |
| 978 | // section just for PLT entries. |
| 979 | |
| 980 | Output_data_plt_i386::Output_data_plt_i386(Layout* layout, |
| 981 | uint64_t addralign, |
| 982 | Output_data_space* got_plt, |
| 983 | Output_data_space* got_irelative) |
| 984 | : Output_section_data(addralign), |
| 985 | layout_(layout), tls_desc_rel_(NULL), |
| 986 | irelative_rel_(NULL), got_plt_(got_plt), got_irelative_(got_irelative), |
| 987 | count_(0), irelative_count_(0), global_ifuncs_(), local_ifuncs_() |
| 988 | { |
| 989 | this->rel_ = new Reloc_section(false); |
| 990 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| 991 | elfcpp::SHF_ALLOC, this->rel_, |
| 992 | ORDER_DYNAMIC_PLT_RELOCS, false); |
| 993 | } |
| 994 | |
| 995 | void |
| 996 | Output_data_plt_i386::do_adjust_output_section(Output_section* os) |
| 997 | { |
| 998 | // UnixWare sets the entsize of .plt to 4, and so does the old GNU |
| 999 | // linker, and so do we. |
| 1000 | os->set_entsize(4); |
| 1001 | } |
| 1002 | |
| 1003 | // Add an entry to the PLT. |
| 1004 | |
| 1005 | void |
| 1006 | Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout, |
| 1007 | Symbol* gsym) |
| 1008 | { |
| 1009 | gold_assert(!gsym->has_plt_offset()); |
| 1010 | |
| 1011 | // Every PLT entry needs a reloc. |
| 1012 | if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 1013 | && gsym->can_use_relative_reloc(false)) |
| 1014 | { |
| 1015 | gsym->set_plt_offset(this->irelative_count_ * this->get_plt_entry_size()); |
| 1016 | ++this->irelative_count_; |
| 1017 | section_offset_type got_offset = |
| 1018 | this->got_irelative_->current_data_size(); |
| 1019 | this->got_irelative_->set_current_data_size(got_offset + 4); |
| 1020 | Reloc_section* rel = this->rel_irelative(symtab, layout); |
| 1021 | rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE, |
| 1022 | this->got_irelative_, got_offset); |
| 1023 | struct Global_ifunc gi; |
| 1024 | gi.sym = gsym; |
| 1025 | gi.got_offset = got_offset; |
| 1026 | this->global_ifuncs_.push_back(gi); |
| 1027 | } |
| 1028 | else |
| 1029 | { |
| 1030 | // When setting the PLT offset we skip the initial reserved PLT |
| 1031 | // entry. |
| 1032 | gsym->set_plt_offset((this->count_ + 1) * this->get_plt_entry_size()); |
| 1033 | |
| 1034 | ++this->count_; |
| 1035 | |
| 1036 | section_offset_type got_offset = this->got_plt_->current_data_size(); |
| 1037 | |
| 1038 | // Every PLT entry needs a GOT entry which points back to the |
| 1039 | // PLT entry (this will be changed by the dynamic linker, |
| 1040 | // normally lazily when the function is called). |
| 1041 | this->got_plt_->set_current_data_size(got_offset + 4); |
| 1042 | |
| 1043 | gsym->set_needs_dynsym_entry(); |
| 1044 | this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_, |
| 1045 | got_offset); |
| 1046 | } |
| 1047 | |
| 1048 | // Note that we don't need to save the symbol. The contents of the |
| 1049 | // PLT are independent of which symbols are used. The symbols only |
| 1050 | // appear in the relocations. |
| 1051 | } |
| 1052 | |
| 1053 | // Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return |
| 1054 | // the PLT offset. |
| 1055 | |
| 1056 | unsigned int |
| 1057 | Output_data_plt_i386::add_local_ifunc_entry( |
| 1058 | Symbol_table* symtab, |
| 1059 | Layout* layout, |
| 1060 | Sized_relobj_file<32, false>* relobj, |
| 1061 | unsigned int local_sym_index) |
| 1062 | { |
| 1063 | unsigned int plt_offset = this->irelative_count_ * this->get_plt_entry_size(); |
| 1064 | ++this->irelative_count_; |
| 1065 | |
| 1066 | section_offset_type got_offset = this->got_irelative_->current_data_size(); |
| 1067 | |
| 1068 | // Every PLT entry needs a GOT entry which points back to the PLT |
| 1069 | // entry. |
| 1070 | this->got_irelative_->set_current_data_size(got_offset + 4); |
| 1071 | |
| 1072 | // Every PLT entry needs a reloc. |
| 1073 | Reloc_section* rel = this->rel_irelative(symtab, layout); |
| 1074 | rel->add_symbolless_local_addend(relobj, local_sym_index, |
| 1075 | elfcpp::R_386_IRELATIVE, |
| 1076 | this->got_irelative_, got_offset); |
| 1077 | |
| 1078 | struct Local_ifunc li; |
| 1079 | li.object = relobj; |
| 1080 | li.local_sym_index = local_sym_index; |
| 1081 | li.got_offset = got_offset; |
| 1082 | this->local_ifuncs_.push_back(li); |
| 1083 | |
| 1084 | return plt_offset; |
| 1085 | } |
| 1086 | |
| 1087 | // Return where the TLS_DESC relocations should go, creating it if |
| 1088 | // necessary. These follow the JUMP_SLOT relocations. |
| 1089 | |
| 1090 | Output_data_plt_i386::Reloc_section* |
| 1091 | Output_data_plt_i386::rel_tls_desc(Layout* layout) |
| 1092 | { |
| 1093 | if (this->tls_desc_rel_ == NULL) |
| 1094 | { |
| 1095 | this->tls_desc_rel_ = new Reloc_section(false); |
| 1096 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| 1097 | elfcpp::SHF_ALLOC, this->tls_desc_rel_, |
| 1098 | ORDER_DYNAMIC_PLT_RELOCS, false); |
| 1099 | gold_assert(this->tls_desc_rel_->output_section() |
| 1100 | == this->rel_->output_section()); |
| 1101 | } |
| 1102 | return this->tls_desc_rel_; |
| 1103 | } |
| 1104 | |
| 1105 | // Return where the IRELATIVE relocations should go in the PLT. These |
| 1106 | // follow the JUMP_SLOT and TLS_DESC relocations. |
| 1107 | |
| 1108 | Output_data_plt_i386::Reloc_section* |
| 1109 | Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout) |
| 1110 | { |
| 1111 | if (this->irelative_rel_ == NULL) |
| 1112 | { |
| 1113 | // Make sure we have a place for the TLS_DESC relocations, in |
| 1114 | // case we see any later on. |
| 1115 | this->rel_tls_desc(layout); |
| 1116 | this->irelative_rel_ = new Reloc_section(false); |
| 1117 | layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL, |
| 1118 | elfcpp::SHF_ALLOC, this->irelative_rel_, |
| 1119 | ORDER_DYNAMIC_PLT_RELOCS, false); |
| 1120 | gold_assert(this->irelative_rel_->output_section() |
| 1121 | == this->rel_->output_section()); |
| 1122 | |
| 1123 | if (parameters->doing_static_link()) |
| 1124 | { |
| 1125 | // A statically linked executable will only have a .rel.plt |
| 1126 | // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC |
| 1127 | // symbols. The library will use these symbols to locate |
| 1128 | // the IRELATIVE relocs at program startup time. |
| 1129 | symtab->define_in_output_data("__rel_iplt_start", NULL, |
| 1130 | Symbol_table::PREDEFINED, |
| 1131 | this->irelative_rel_, 0, 0, |
| 1132 | elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, |
| 1133 | elfcpp::STV_HIDDEN, 0, false, true); |
| 1134 | symtab->define_in_output_data("__rel_iplt_end", NULL, |
| 1135 | Symbol_table::PREDEFINED, |
| 1136 | this->irelative_rel_, 0, 0, |
| 1137 | elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL, |
| 1138 | elfcpp::STV_HIDDEN, 0, true, true); |
| 1139 | } |
| 1140 | } |
| 1141 | return this->irelative_rel_; |
| 1142 | } |
| 1143 | |
| 1144 | // Return the PLT address to use for a global symbol. |
| 1145 | |
| 1146 | uint64_t |
| 1147 | Output_data_plt_i386::address_for_global(const Symbol* gsym) |
| 1148 | { |
| 1149 | uint64_t offset = 0; |
| 1150 | if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 1151 | && gsym->can_use_relative_reloc(false)) |
| 1152 | offset = (this->count_ + 1) * this->get_plt_entry_size(); |
| 1153 | return this->address() + offset + gsym->plt_offset(); |
| 1154 | } |
| 1155 | |
| 1156 | // Return the PLT address to use for a local symbol. These are always |
| 1157 | // IRELATIVE relocs. |
| 1158 | |
| 1159 | uint64_t |
| 1160 | Output_data_plt_i386::address_for_local(const Relobj* object, |
| 1161 | unsigned int r_sym) |
| 1162 | { |
| 1163 | return (this->address() |
| 1164 | + (this->count_ + 1) * this->get_plt_entry_size() |
| 1165 | + object->local_plt_offset(r_sym)); |
| 1166 | } |
| 1167 | |
| 1168 | // The first entry in the PLT for an executable. |
| 1169 | |
| 1170 | const unsigned char Output_data_plt_i386_exec::first_plt_entry[plt_entry_size] = |
| 1171 | { |
| 1172 | 0xff, 0x35, // pushl contents of memory address |
| 1173 | 0, 0, 0, 0, // replaced with address of .got + 4 |
| 1174 | 0xff, 0x25, // jmp indirect |
| 1175 | 0, 0, 0, 0, // replaced with address of .got + 8 |
| 1176 | 0, 0, 0, 0 // unused |
| 1177 | }; |
| 1178 | |
| 1179 | void |
| 1180 | Output_data_plt_i386_exec::do_fill_first_plt_entry( |
| 1181 | unsigned char* pov, |
| 1182 | elfcpp::Elf_types<32>::Elf_Addr got_address) |
| 1183 | { |
| 1184 | memcpy(pov, first_plt_entry, plt_entry_size); |
| 1185 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4); |
| 1186 | elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8); |
| 1187 | } |
| 1188 | |
| 1189 | // The first entry in the PLT for a shared object. |
| 1190 | |
| 1191 | const unsigned char Output_data_plt_i386_dyn::first_plt_entry[plt_entry_size] = |
| 1192 | { |
| 1193 | 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) |
| 1194 | 0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx) |
| 1195 | 0, 0, 0, 0 // unused |
| 1196 | }; |
| 1197 | |
| 1198 | void |
| 1199 | Output_data_plt_i386_dyn::do_fill_first_plt_entry( |
| 1200 | unsigned char* pov, |
| 1201 | elfcpp::Elf_types<32>::Elf_Addr) |
| 1202 | { |
| 1203 | memcpy(pov, first_plt_entry, plt_entry_size); |
| 1204 | } |
| 1205 | |
| 1206 | // Subsequent entries in the PLT for an executable. |
| 1207 | |
| 1208 | const unsigned char Output_data_plt_i386_exec::plt_entry[plt_entry_size] = |
| 1209 | { |
| 1210 | 0xff, 0x25, // jmp indirect |
| 1211 | 0, 0, 0, 0, // replaced with address of symbol in .got |
| 1212 | 0x68, // pushl immediate |
| 1213 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 1214 | 0xe9, // jmp relative |
| 1215 | 0, 0, 0, 0 // replaced with offset to start of .plt |
| 1216 | }; |
| 1217 | |
| 1218 | unsigned int |
| 1219 | Output_data_plt_i386_exec::do_fill_plt_entry( |
| 1220 | unsigned char* pov, |
| 1221 | elfcpp::Elf_types<32>::Elf_Addr got_address, |
| 1222 | unsigned int got_offset, |
| 1223 | unsigned int plt_offset, |
| 1224 | unsigned int plt_rel_offset) |
| 1225 | { |
| 1226 | memcpy(pov, plt_entry, plt_entry_size); |
| 1227 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| 1228 | got_address + got_offset); |
| 1229 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| 1230 | elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4)); |
| 1231 | return 6; |
| 1232 | } |
| 1233 | |
| 1234 | // Subsequent entries in the PLT for a shared object. |
| 1235 | |
| 1236 | const unsigned char Output_data_plt_i386_dyn::plt_entry[plt_entry_size] = |
| 1237 | { |
| 1238 | 0xff, 0xa3, // jmp *offset(%ebx) |
| 1239 | 0, 0, 0, 0, // replaced with offset of symbol in .got |
| 1240 | 0x68, // pushl immediate |
| 1241 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 1242 | 0xe9, // jmp relative |
| 1243 | 0, 0, 0, 0 // replaced with offset to start of .plt |
| 1244 | }; |
| 1245 | |
| 1246 | unsigned int |
| 1247 | Output_data_plt_i386_dyn::do_fill_plt_entry(unsigned char* pov, |
| 1248 | elfcpp::Elf_types<32>::Elf_Addr, |
| 1249 | unsigned int got_offset, |
| 1250 | unsigned int plt_offset, |
| 1251 | unsigned int plt_rel_offset) |
| 1252 | { |
| 1253 | memcpy(pov, plt_entry, plt_entry_size); |
| 1254 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); |
| 1255 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset); |
| 1256 | elfcpp::Swap<32, false>::writeval(pov + 12, - (plt_offset + 12 + 4)); |
| 1257 | return 6; |
| 1258 | } |
| 1259 | |
| 1260 | // The .eh_frame unwind information for the PLT. |
| 1261 | |
| 1262 | const unsigned char |
| 1263 | Output_data_plt_i386::plt_eh_frame_cie[plt_eh_frame_cie_size] = |
| 1264 | { |
| 1265 | 1, // CIE version. |
| 1266 | 'z', // Augmentation: augmentation size included. |
| 1267 | 'R', // Augmentation: FDE encoding included. |
| 1268 | '\0', // End of augmentation string. |
| 1269 | 1, // Code alignment factor. |
| 1270 | 0x7c, // Data alignment factor. |
| 1271 | 8, // Return address column. |
| 1272 | 1, // Augmentation size. |
| 1273 | (elfcpp::DW_EH_PE_pcrel // FDE encoding. |
| 1274 | | elfcpp::DW_EH_PE_sdata4), |
| 1275 | elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4. |
| 1276 | elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4. |
| 1277 | elfcpp::DW_CFA_nop, // Align to 16 bytes. |
| 1278 | elfcpp::DW_CFA_nop |
| 1279 | }; |
| 1280 | |
| 1281 | const unsigned char |
| 1282 | Output_data_plt_i386_standard::plt_eh_frame_fde[plt_eh_frame_fde_size] = |
| 1283 | { |
| 1284 | 0, 0, 0, 0, // Replaced with offset to .plt. |
| 1285 | 0, 0, 0, 0, // Replaced with size of .plt. |
| 1286 | 0, // Augmentation size. |
| 1287 | elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8. |
| 1288 | elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. |
| 1289 | elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12. |
| 1290 | elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16. |
| 1291 | elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. |
| 1292 | 11, // Block length. |
| 1293 | elfcpp::DW_OP_breg4, 4, // Push %esp + 4. |
| 1294 | elfcpp::DW_OP_breg8, 0, // Push %eip. |
| 1295 | elfcpp::DW_OP_lit15, // Push 0xf. |
| 1296 | elfcpp::DW_OP_and, // & (%eip & 0xf). |
| 1297 | elfcpp::DW_OP_lit11, // Push 0xb. |
| 1298 | elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb) |
| 1299 | elfcpp::DW_OP_lit2, // Push 2. |
| 1300 | elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2) |
| 1301 | elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+4 |
| 1302 | elfcpp::DW_CFA_nop, // Align to 32 bytes. |
| 1303 | elfcpp::DW_CFA_nop, |
| 1304 | elfcpp::DW_CFA_nop, |
| 1305 | elfcpp::DW_CFA_nop |
| 1306 | }; |
| 1307 | |
| 1308 | // Write out the PLT. This uses the hand-coded instructions above, |
| 1309 | // and adjusts them as needed. This is all specified by the i386 ELF |
| 1310 | // Processor Supplement. |
| 1311 | |
| 1312 | void |
| 1313 | Output_data_plt_i386::do_write(Output_file* of) |
| 1314 | { |
| 1315 | const off_t offset = this->offset(); |
| 1316 | const section_size_type oview_size = |
| 1317 | convert_to_section_size_type(this->data_size()); |
| 1318 | unsigned char* const oview = of->get_output_view(offset, oview_size); |
| 1319 | |
| 1320 | const off_t got_file_offset = this->got_plt_->offset(); |
| 1321 | gold_assert(parameters->incremental_update() |
| 1322 | || (got_file_offset + this->got_plt_->data_size() |
| 1323 | == this->got_irelative_->offset())); |
| 1324 | const section_size_type got_size = |
| 1325 | convert_to_section_size_type(this->got_plt_->data_size() |
| 1326 | + this->got_irelative_->data_size()); |
| 1327 | unsigned char* const got_view = of->get_output_view(got_file_offset, |
| 1328 | got_size); |
| 1329 | |
| 1330 | unsigned char* pov = oview; |
| 1331 | |
| 1332 | elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address(); |
| 1333 | elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address(); |
| 1334 | |
| 1335 | this->fill_first_plt_entry(pov, got_address); |
| 1336 | pov += this->get_plt_entry_size(); |
| 1337 | |
| 1338 | unsigned char* got_pov = got_view; |
| 1339 | |
| 1340 | // The first entry in the GOT is the address of the .dynamic section |
| 1341 | // aka the PT_DYNAMIC segment. The next two entries are reserved. |
| 1342 | // We saved space for them when we created the section in |
| 1343 | // Target_i386::got_section. |
| 1344 | Output_section* dynamic = this->layout_->dynamic_section(); |
| 1345 | uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address(); |
| 1346 | elfcpp::Swap<32, false>::writeval(got_pov, dynamic_addr); |
| 1347 | got_pov += 4; |
| 1348 | memset(got_pov, 0, 8); |
| 1349 | got_pov += 8; |
| 1350 | |
| 1351 | const int rel_size = elfcpp::Elf_sizes<32>::rel_size; |
| 1352 | |
| 1353 | unsigned int plt_offset = this->get_plt_entry_size(); |
| 1354 | unsigned int plt_rel_offset = 0; |
| 1355 | unsigned int got_offset = 12; |
| 1356 | const unsigned int count = this->count_ + this->irelative_count_; |
| 1357 | for (unsigned int i = 0; |
| 1358 | i < count; |
| 1359 | ++i, |
| 1360 | pov += this->get_plt_entry_size(), |
| 1361 | got_pov += 4, |
| 1362 | plt_offset += this->get_plt_entry_size(), |
| 1363 | plt_rel_offset += rel_size, |
| 1364 | got_offset += 4) |
| 1365 | { |
| 1366 | // Set and adjust the PLT entry itself. |
| 1367 | unsigned int lazy_offset = this->fill_plt_entry(pov, |
| 1368 | got_address, |
| 1369 | got_offset, |
| 1370 | plt_offset, |
| 1371 | plt_rel_offset); |
| 1372 | |
| 1373 | // Set the entry in the GOT. |
| 1374 | elfcpp::Swap<32, false>::writeval(got_pov, |
| 1375 | plt_address + plt_offset + lazy_offset); |
| 1376 | } |
| 1377 | |
| 1378 | // If any STT_GNU_IFUNC symbols have PLT entries, we need to change |
| 1379 | // the GOT to point to the actual symbol value, rather than point to |
| 1380 | // the PLT entry. That will let the dynamic linker call the right |
| 1381 | // function when resolving IRELATIVE relocations. |
| 1382 | unsigned char* got_irelative_view = got_view + this->got_plt_->data_size(); |
| 1383 | for (std::vector<Global_ifunc>::const_iterator p = |
| 1384 | this->global_ifuncs_.begin(); |
| 1385 | p != this->global_ifuncs_.end(); |
| 1386 | ++p) |
| 1387 | { |
| 1388 | const Sized_symbol<32>* ssym = |
| 1389 | static_cast<const Sized_symbol<32>*>(p->sym); |
| 1390 | elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset, |
| 1391 | ssym->value()); |
| 1392 | } |
| 1393 | |
| 1394 | for (std::vector<Local_ifunc>::const_iterator p = |
| 1395 | this->local_ifuncs_.begin(); |
| 1396 | p != this->local_ifuncs_.end(); |
| 1397 | ++p) |
| 1398 | { |
| 1399 | const Symbol_value<32>* psymval = |
| 1400 | p->object->local_symbol(p->local_sym_index); |
| 1401 | elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset, |
| 1402 | psymval->value(p->object, 0)); |
| 1403 | } |
| 1404 | |
| 1405 | gold_assert(static_cast<section_size_type>(pov - oview) == oview_size); |
| 1406 | gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size); |
| 1407 | |
| 1408 | of->write_output_view(offset, oview_size, oview); |
| 1409 | of->write_output_view(got_file_offset, got_size, got_view); |
| 1410 | } |
| 1411 | |
| 1412 | // Create the PLT section. |
| 1413 | |
| 1414 | void |
| 1415 | Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout) |
| 1416 | { |
| 1417 | if (this->plt_ == NULL) |
| 1418 | { |
| 1419 | // Create the GOT sections first. |
| 1420 | this->got_section(symtab, layout); |
| 1421 | |
| 1422 | const bool dyn = parameters->options().output_is_position_independent(); |
| 1423 | this->plt_ = this->make_data_plt(layout, |
| 1424 | this->got_plt_, |
| 1425 | this->got_irelative_, |
| 1426 | dyn); |
| 1427 | |
| 1428 | // Add unwind information if requested. |
| 1429 | if (parameters->options().ld_generated_unwind_info()) |
| 1430 | this->plt_->add_eh_frame(layout); |
| 1431 | |
| 1432 | layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS, |
| 1433 | (elfcpp::SHF_ALLOC |
| 1434 | | elfcpp::SHF_EXECINSTR), |
| 1435 | this->plt_, ORDER_PLT, false); |
| 1436 | |
| 1437 | // Make the sh_info field of .rel.plt point to .plt. |
| 1438 | Output_section* rel_plt_os = this->plt_->rel_plt()->output_section(); |
| 1439 | rel_plt_os->set_info_section(this->plt_->output_section()); |
| 1440 | } |
| 1441 | } |
| 1442 | |
| 1443 | // Create a PLT entry for a global symbol. |
| 1444 | |
| 1445 | void |
| 1446 | Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym) |
| 1447 | { |
| 1448 | if (gsym->has_plt_offset()) |
| 1449 | return; |
| 1450 | if (this->plt_ == NULL) |
| 1451 | this->make_plt_section(symtab, layout); |
| 1452 | this->plt_->add_entry(symtab, layout, gsym); |
| 1453 | } |
| 1454 | |
| 1455 | // Make a PLT entry for a local STT_GNU_IFUNC symbol. |
| 1456 | |
| 1457 | void |
| 1458 | Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout, |
| 1459 | Sized_relobj_file<32, false>* relobj, |
| 1460 | unsigned int local_sym_index) |
| 1461 | { |
| 1462 | if (relobj->local_has_plt_offset(local_sym_index)) |
| 1463 | return; |
| 1464 | if (this->plt_ == NULL) |
| 1465 | this->make_plt_section(symtab, layout); |
| 1466 | unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout, |
| 1467 | relobj, |
| 1468 | local_sym_index); |
| 1469 | relobj->set_local_plt_offset(local_sym_index, plt_offset); |
| 1470 | } |
| 1471 | |
| 1472 | // Return the number of entries in the PLT. |
| 1473 | |
| 1474 | unsigned int |
| 1475 | Target_i386::plt_entry_count() const |
| 1476 | { |
| 1477 | if (this->plt_ == NULL) |
| 1478 | return 0; |
| 1479 | return this->plt_->entry_count(); |
| 1480 | } |
| 1481 | |
| 1482 | // Return the offset of the first non-reserved PLT entry. |
| 1483 | |
| 1484 | unsigned int |
| 1485 | Target_i386::first_plt_entry_offset() const |
| 1486 | { |
| 1487 | return this->plt_->first_plt_entry_offset(); |
| 1488 | } |
| 1489 | |
| 1490 | // Return the size of each PLT entry. |
| 1491 | |
| 1492 | unsigned int |
| 1493 | Target_i386::plt_entry_size() const |
| 1494 | { |
| 1495 | return this->plt_->get_plt_entry_size(); |
| 1496 | } |
| 1497 | |
| 1498 | // Get the section to use for TLS_DESC relocations. |
| 1499 | |
| 1500 | Target_i386::Reloc_section* |
| 1501 | Target_i386::rel_tls_desc_section(Layout* layout) const |
| 1502 | { |
| 1503 | return this->plt_section()->rel_tls_desc(layout); |
| 1504 | } |
| 1505 | |
| 1506 | // Define the _TLS_MODULE_BASE_ symbol in the TLS segment. |
| 1507 | |
| 1508 | void |
| 1509 | Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout) |
| 1510 | { |
| 1511 | if (this->tls_base_symbol_defined_) |
| 1512 | return; |
| 1513 | |
| 1514 | Output_segment* tls_segment = layout->tls_segment(); |
| 1515 | if (tls_segment != NULL) |
| 1516 | { |
| 1517 | bool is_exec = parameters->options().output_is_executable(); |
| 1518 | symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL, |
| 1519 | Symbol_table::PREDEFINED, |
| 1520 | tls_segment, 0, 0, |
| 1521 | elfcpp::STT_TLS, |
| 1522 | elfcpp::STB_LOCAL, |
| 1523 | elfcpp::STV_HIDDEN, 0, |
| 1524 | (is_exec |
| 1525 | ? Symbol::SEGMENT_END |
| 1526 | : Symbol::SEGMENT_START), |
| 1527 | true); |
| 1528 | } |
| 1529 | this->tls_base_symbol_defined_ = true; |
| 1530 | } |
| 1531 | |
| 1532 | // Create a GOT entry for the TLS module index. |
| 1533 | |
| 1534 | unsigned int |
| 1535 | Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout, |
| 1536 | Sized_relobj_file<32, false>* object) |
| 1537 | { |
| 1538 | if (this->got_mod_index_offset_ == -1U) |
| 1539 | { |
| 1540 | gold_assert(symtab != NULL && layout != NULL && object != NULL); |
| 1541 | Reloc_section* rel_dyn = this->rel_dyn_section(layout); |
| 1542 | Output_data_got<32, false>* got = this->got_section(symtab, layout); |
| 1543 | unsigned int got_offset = got->add_constant(0); |
| 1544 | rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got, |
| 1545 | got_offset); |
| 1546 | got->add_constant(0); |
| 1547 | this->got_mod_index_offset_ = got_offset; |
| 1548 | } |
| 1549 | return this->got_mod_index_offset_; |
| 1550 | } |
| 1551 | |
| 1552 | // Optimize the TLS relocation type based on what we know about the |
| 1553 | // symbol. IS_FINAL is true if the final address of this symbol is |
| 1554 | // known at link time. |
| 1555 | |
| 1556 | tls::Tls_optimization |
| 1557 | Target_i386::optimize_tls_reloc(bool is_final, int r_type) |
| 1558 | { |
| 1559 | // If we are generating a shared library, then we can't do anything |
| 1560 | // in the linker. |
| 1561 | if (parameters->options().shared()) |
| 1562 | return tls::TLSOPT_NONE; |
| 1563 | |
| 1564 | switch (r_type) |
| 1565 | { |
| 1566 | case elfcpp::R_386_TLS_GD: |
| 1567 | case elfcpp::R_386_TLS_GOTDESC: |
| 1568 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1569 | // These are General-Dynamic which permits fully general TLS |
| 1570 | // access. Since we know that we are generating an executable, |
| 1571 | // we can convert this to Initial-Exec. If we also know that |
| 1572 | // this is a local symbol, we can further switch to Local-Exec. |
| 1573 | if (is_final) |
| 1574 | return tls::TLSOPT_TO_LE; |
| 1575 | return tls::TLSOPT_TO_IE; |
| 1576 | |
| 1577 | case elfcpp::R_386_TLS_LDM: |
| 1578 | // This is Local-Dynamic, which refers to a local symbol in the |
| 1579 | // dynamic TLS block. Since we know that we generating an |
| 1580 | // executable, we can switch to Local-Exec. |
| 1581 | return tls::TLSOPT_TO_LE; |
| 1582 | |
| 1583 | case elfcpp::R_386_TLS_LDO_32: |
| 1584 | // Another type of Local-Dynamic relocation. |
| 1585 | return tls::TLSOPT_TO_LE; |
| 1586 | |
| 1587 | case elfcpp::R_386_TLS_IE: |
| 1588 | case elfcpp::R_386_TLS_GOTIE: |
| 1589 | case elfcpp::R_386_TLS_IE_32: |
| 1590 | // These are Initial-Exec relocs which get the thread offset |
| 1591 | // from the GOT. If we know that we are linking against the |
| 1592 | // local symbol, we can switch to Local-Exec, which links the |
| 1593 | // thread offset into the instruction. |
| 1594 | if (is_final) |
| 1595 | return tls::TLSOPT_TO_LE; |
| 1596 | return tls::TLSOPT_NONE; |
| 1597 | |
| 1598 | case elfcpp::R_386_TLS_LE: |
| 1599 | case elfcpp::R_386_TLS_LE_32: |
| 1600 | // When we already have Local-Exec, there is nothing further we |
| 1601 | // can do. |
| 1602 | return tls::TLSOPT_NONE; |
| 1603 | |
| 1604 | default: |
| 1605 | gold_unreachable(); |
| 1606 | } |
| 1607 | } |
| 1608 | |
| 1609 | // Get the Reference_flags for a particular relocation. |
| 1610 | |
| 1611 | int |
| 1612 | Target_i386::Scan::get_reference_flags(unsigned int r_type) |
| 1613 | { |
| 1614 | switch (r_type) |
| 1615 | { |
| 1616 | case elfcpp::R_386_NONE: |
| 1617 | case elfcpp::R_386_GNU_VTINHERIT: |
| 1618 | case elfcpp::R_386_GNU_VTENTRY: |
| 1619 | case elfcpp::R_386_GOTPC: |
| 1620 | // No symbol reference. |
| 1621 | return 0; |
| 1622 | |
| 1623 | case elfcpp::R_386_32: |
| 1624 | case elfcpp::R_386_16: |
| 1625 | case elfcpp::R_386_8: |
| 1626 | return Symbol::ABSOLUTE_REF; |
| 1627 | |
| 1628 | case elfcpp::R_386_PC32: |
| 1629 | case elfcpp::R_386_PC16: |
| 1630 | case elfcpp::R_386_PC8: |
| 1631 | case elfcpp::R_386_GOTOFF: |
| 1632 | return Symbol::RELATIVE_REF; |
| 1633 | |
| 1634 | case elfcpp::R_386_PLT32: |
| 1635 | return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF; |
| 1636 | |
| 1637 | case elfcpp::R_386_GOT32: |
| 1638 | // Absolute in GOT. |
| 1639 | return Symbol::ABSOLUTE_REF; |
| 1640 | |
| 1641 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1642 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 1643 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1644 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1645 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1646 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1647 | case elfcpp::R_386_TLS_IE_32: |
| 1648 | case elfcpp::R_386_TLS_GOTIE: |
| 1649 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1650 | case elfcpp::R_386_TLS_LE_32: |
| 1651 | return Symbol::TLS_REF; |
| 1652 | |
| 1653 | case elfcpp::R_386_COPY: |
| 1654 | case elfcpp::R_386_GLOB_DAT: |
| 1655 | case elfcpp::R_386_JUMP_SLOT: |
| 1656 | case elfcpp::R_386_RELATIVE: |
| 1657 | case elfcpp::R_386_IRELATIVE: |
| 1658 | case elfcpp::R_386_TLS_TPOFF: |
| 1659 | case elfcpp::R_386_TLS_DTPMOD32: |
| 1660 | case elfcpp::R_386_TLS_DTPOFF32: |
| 1661 | case elfcpp::R_386_TLS_TPOFF32: |
| 1662 | case elfcpp::R_386_TLS_DESC: |
| 1663 | case elfcpp::R_386_32PLT: |
| 1664 | case elfcpp::R_386_TLS_GD_32: |
| 1665 | case elfcpp::R_386_TLS_GD_PUSH: |
| 1666 | case elfcpp::R_386_TLS_GD_CALL: |
| 1667 | case elfcpp::R_386_TLS_GD_POP: |
| 1668 | case elfcpp::R_386_TLS_LDM_32: |
| 1669 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 1670 | case elfcpp::R_386_TLS_LDM_CALL: |
| 1671 | case elfcpp::R_386_TLS_LDM_POP: |
| 1672 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 1673 | default: |
| 1674 | // Not expected. We will give an error later. |
| 1675 | return 0; |
| 1676 | } |
| 1677 | } |
| 1678 | |
| 1679 | // Report an unsupported relocation against a local symbol. |
| 1680 | |
| 1681 | void |
| 1682 | Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object, |
| 1683 | unsigned int r_type) |
| 1684 | { |
| 1685 | gold_error(_("%s: unsupported reloc %u against local symbol"), |
| 1686 | object->name().c_str(), r_type); |
| 1687 | } |
| 1688 | |
| 1689 | // Return whether we need to make a PLT entry for a relocation of a |
| 1690 | // given type against a STT_GNU_IFUNC symbol. |
| 1691 | |
| 1692 | bool |
| 1693 | Target_i386::Scan::reloc_needs_plt_for_ifunc( |
| 1694 | Sized_relobj_file<32, false>* object, |
| 1695 | unsigned int r_type) |
| 1696 | { |
| 1697 | int flags = Scan::get_reference_flags(r_type); |
| 1698 | if (flags & Symbol::TLS_REF) |
| 1699 | gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"), |
| 1700 | object->name().c_str(), r_type); |
| 1701 | return flags != 0; |
| 1702 | } |
| 1703 | |
| 1704 | // Scan a relocation for a local symbol. |
| 1705 | |
| 1706 | inline void |
| 1707 | Target_i386::Scan::local(Symbol_table* symtab, |
| 1708 | Layout* layout, |
| 1709 | Target_i386* target, |
| 1710 | Sized_relobj_file<32, false>* object, |
| 1711 | unsigned int data_shndx, |
| 1712 | Output_section* output_section, |
| 1713 | const elfcpp::Rel<32, false>& reloc, |
| 1714 | unsigned int r_type, |
| 1715 | const elfcpp::Sym<32, false>& lsym, |
| 1716 | bool is_discarded) |
| 1717 | { |
| 1718 | if (is_discarded) |
| 1719 | return; |
| 1720 | |
| 1721 | // A local STT_GNU_IFUNC symbol may require a PLT entry. |
| 1722 | if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC |
| 1723 | && this->reloc_needs_plt_for_ifunc(object, r_type)) |
| 1724 | { |
| 1725 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1726 | target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym); |
| 1727 | } |
| 1728 | |
| 1729 | switch (r_type) |
| 1730 | { |
| 1731 | case elfcpp::R_386_NONE: |
| 1732 | case elfcpp::R_386_GNU_VTINHERIT: |
| 1733 | case elfcpp::R_386_GNU_VTENTRY: |
| 1734 | break; |
| 1735 | |
| 1736 | case elfcpp::R_386_32: |
| 1737 | // If building a shared library (or a position-independent |
| 1738 | // executable), we need to create a dynamic relocation for |
| 1739 | // this location. The relocation applied at link time will |
| 1740 | // apply the link-time value, so we flag the location with |
| 1741 | // an R_386_RELATIVE relocation so the dynamic loader can |
| 1742 | // relocate it easily. |
| 1743 | if (parameters->options().output_is_position_independent()) |
| 1744 | { |
| 1745 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1746 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1747 | rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE, |
| 1748 | output_section, data_shndx, |
| 1749 | reloc.get_r_offset()); |
| 1750 | } |
| 1751 | break; |
| 1752 | |
| 1753 | case elfcpp::R_386_16: |
| 1754 | case elfcpp::R_386_8: |
| 1755 | // If building a shared library (or a position-independent |
| 1756 | // executable), we need to create a dynamic relocation for |
| 1757 | // this location. Because the addend needs to remain in the |
| 1758 | // data section, we need to be careful not to apply this |
| 1759 | // relocation statically. |
| 1760 | if (parameters->options().output_is_position_independent()) |
| 1761 | { |
| 1762 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1763 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1764 | if (lsym.get_st_type() != elfcpp::STT_SECTION) |
| 1765 | rel_dyn->add_local(object, r_sym, r_type, output_section, |
| 1766 | data_shndx, reloc.get_r_offset()); |
| 1767 | else |
| 1768 | { |
| 1769 | gold_assert(lsym.get_st_value() == 0); |
| 1770 | unsigned int shndx = lsym.get_st_shndx(); |
| 1771 | bool is_ordinary; |
| 1772 | shndx = object->adjust_sym_shndx(r_sym, shndx, |
| 1773 | &is_ordinary); |
| 1774 | if (!is_ordinary) |
| 1775 | object->error(_("section symbol %u has bad shndx %u"), |
| 1776 | r_sym, shndx); |
| 1777 | else |
| 1778 | rel_dyn->add_local_section(object, shndx, |
| 1779 | r_type, output_section, |
| 1780 | data_shndx, reloc.get_r_offset()); |
| 1781 | } |
| 1782 | } |
| 1783 | break; |
| 1784 | |
| 1785 | case elfcpp::R_386_PC32: |
| 1786 | case elfcpp::R_386_PC16: |
| 1787 | case elfcpp::R_386_PC8: |
| 1788 | break; |
| 1789 | |
| 1790 | case elfcpp::R_386_PLT32: |
| 1791 | // Since we know this is a local symbol, we can handle this as a |
| 1792 | // PC32 reloc. |
| 1793 | break; |
| 1794 | |
| 1795 | case elfcpp::R_386_GOTOFF: |
| 1796 | case elfcpp::R_386_GOTPC: |
| 1797 | // We need a GOT section. |
| 1798 | target->got_section(symtab, layout); |
| 1799 | break; |
| 1800 | |
| 1801 | case elfcpp::R_386_GOT32: |
| 1802 | { |
| 1803 | // The symbol requires a GOT entry. |
| 1804 | Output_data_got<32, false>* got = target->got_section(symtab, layout); |
| 1805 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1806 | |
| 1807 | // For a STT_GNU_IFUNC symbol we want the PLT offset. That |
| 1808 | // lets function pointers compare correctly with shared |
| 1809 | // libraries. Otherwise we would need an IRELATIVE reloc. |
| 1810 | bool is_new; |
| 1811 | if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC) |
| 1812 | is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD); |
| 1813 | else |
| 1814 | is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD); |
| 1815 | if (is_new) |
| 1816 | { |
| 1817 | // If we are generating a shared object, we need to add a |
| 1818 | // dynamic RELATIVE relocation for this symbol's GOT entry. |
| 1819 | if (parameters->options().output_is_position_independent()) |
| 1820 | { |
| 1821 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1822 | unsigned int got_offset = |
| 1823 | object->local_got_offset(r_sym, GOT_TYPE_STANDARD); |
| 1824 | rel_dyn->add_local_relative(object, r_sym, |
| 1825 | elfcpp::R_386_RELATIVE, |
| 1826 | got, got_offset); |
| 1827 | } |
| 1828 | } |
| 1829 | } |
| 1830 | break; |
| 1831 | |
| 1832 | // These are relocations which should only be seen by the |
| 1833 | // dynamic linker, and should never be seen here. |
| 1834 | case elfcpp::R_386_COPY: |
| 1835 | case elfcpp::R_386_GLOB_DAT: |
| 1836 | case elfcpp::R_386_JUMP_SLOT: |
| 1837 | case elfcpp::R_386_RELATIVE: |
| 1838 | case elfcpp::R_386_IRELATIVE: |
| 1839 | case elfcpp::R_386_TLS_TPOFF: |
| 1840 | case elfcpp::R_386_TLS_DTPMOD32: |
| 1841 | case elfcpp::R_386_TLS_DTPOFF32: |
| 1842 | case elfcpp::R_386_TLS_TPOFF32: |
| 1843 | case elfcpp::R_386_TLS_DESC: |
| 1844 | gold_error(_("%s: unexpected reloc %u in object file"), |
| 1845 | object->name().c_str(), r_type); |
| 1846 | break; |
| 1847 | |
| 1848 | // These are initial TLS relocs, which are expected when |
| 1849 | // linking. |
| 1850 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1851 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 1852 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1853 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1854 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1855 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1856 | case elfcpp::R_386_TLS_IE_32: |
| 1857 | case elfcpp::R_386_TLS_GOTIE: |
| 1858 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1859 | case elfcpp::R_386_TLS_LE_32: |
| 1860 | { |
| 1861 | bool output_is_shared = parameters->options().shared(); |
| 1862 | const tls::Tls_optimization optimized_type |
| 1863 | = Target_i386::optimize_tls_reloc(!output_is_shared, r_type); |
| 1864 | switch (r_type) |
| 1865 | { |
| 1866 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 1867 | if (optimized_type == tls::TLSOPT_NONE) |
| 1868 | { |
| 1869 | // Create a pair of GOT entries for the module index and |
| 1870 | // dtv-relative offset. |
| 1871 | Output_data_got<32, false>* got |
| 1872 | = target->got_section(symtab, layout); |
| 1873 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1874 | unsigned int shndx = lsym.get_st_shndx(); |
| 1875 | bool is_ordinary; |
| 1876 | shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary); |
| 1877 | if (!is_ordinary) |
| 1878 | object->error(_("local symbol %u has bad shndx %u"), |
| 1879 | r_sym, shndx); |
| 1880 | else |
| 1881 | got->add_local_pair_with_rel(object, r_sym, shndx, |
| 1882 | GOT_TYPE_TLS_PAIR, |
| 1883 | target->rel_dyn_section(layout), |
| 1884 | elfcpp::R_386_TLS_DTPMOD32); |
| 1885 | } |
| 1886 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1887 | unsupported_reloc_local(object, r_type); |
| 1888 | break; |
| 1889 | |
| 1890 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva) |
| 1891 | target->define_tls_base_symbol(symtab, layout); |
| 1892 | if (optimized_type == tls::TLSOPT_NONE) |
| 1893 | { |
| 1894 | // Create a double GOT entry with an R_386_TLS_DESC |
| 1895 | // reloc. The R_386_TLS_DESC reloc is resolved |
| 1896 | // lazily, so the GOT entry needs to be in an area in |
| 1897 | // .got.plt, not .got. Call got_section to make sure |
| 1898 | // the section has been created. |
| 1899 | target->got_section(symtab, layout); |
| 1900 | Output_data_got<32, false>* got = target->got_tlsdesc_section(); |
| 1901 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1902 | if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC)) |
| 1903 | { |
| 1904 | unsigned int got_offset = got->add_constant(0); |
| 1905 | // The local symbol value is stored in the second |
| 1906 | // GOT entry. |
| 1907 | got->add_local(object, r_sym, GOT_TYPE_TLS_DESC); |
| 1908 | // That set the GOT offset of the local symbol to |
| 1909 | // point to the second entry, but we want it to |
| 1910 | // point to the first. |
| 1911 | object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC, |
| 1912 | got_offset); |
| 1913 | Reloc_section* rt = target->rel_tls_desc_section(layout); |
| 1914 | rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset); |
| 1915 | } |
| 1916 | } |
| 1917 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1918 | unsupported_reloc_local(object, r_type); |
| 1919 | break; |
| 1920 | |
| 1921 | case elfcpp::R_386_TLS_DESC_CALL: |
| 1922 | break; |
| 1923 | |
| 1924 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 1925 | if (optimized_type == tls::TLSOPT_NONE) |
| 1926 | { |
| 1927 | // Create a GOT entry for the module index. |
| 1928 | target->got_mod_index_entry(symtab, layout, object); |
| 1929 | } |
| 1930 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1931 | unsupported_reloc_local(object, r_type); |
| 1932 | break; |
| 1933 | |
| 1934 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 1935 | break; |
| 1936 | |
| 1937 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 1938 | case elfcpp::R_386_TLS_IE_32: |
| 1939 | case elfcpp::R_386_TLS_GOTIE: |
| 1940 | layout->set_has_static_tls(); |
| 1941 | if (optimized_type == tls::TLSOPT_NONE) |
| 1942 | { |
| 1943 | // For the R_386_TLS_IE relocation, we need to create a |
| 1944 | // dynamic relocation when building a shared library. |
| 1945 | if (r_type == elfcpp::R_386_TLS_IE |
| 1946 | && parameters->options().shared()) |
| 1947 | { |
| 1948 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1949 | unsigned int r_sym |
| 1950 | = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1951 | rel_dyn->add_local_relative(object, r_sym, |
| 1952 | elfcpp::R_386_RELATIVE, |
| 1953 | output_section, data_shndx, |
| 1954 | reloc.get_r_offset()); |
| 1955 | } |
| 1956 | // Create a GOT entry for the tp-relative offset. |
| 1957 | Output_data_got<32, false>* got |
| 1958 | = target->got_section(symtab, layout); |
| 1959 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1960 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 1961 | ? elfcpp::R_386_TLS_TPOFF32 |
| 1962 | : elfcpp::R_386_TLS_TPOFF); |
| 1963 | unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 1964 | ? GOT_TYPE_TLS_OFFSET |
| 1965 | : GOT_TYPE_TLS_NOFFSET); |
| 1966 | got->add_local_with_rel(object, r_sym, got_type, |
| 1967 | target->rel_dyn_section(layout), |
| 1968 | dyn_r_type); |
| 1969 | } |
| 1970 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 1971 | unsupported_reloc_local(object, r_type); |
| 1972 | break; |
| 1973 | |
| 1974 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 1975 | case elfcpp::R_386_TLS_LE_32: |
| 1976 | layout->set_has_static_tls(); |
| 1977 | if (output_is_shared) |
| 1978 | { |
| 1979 | // We need to create a dynamic relocation. |
| 1980 | gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION); |
| 1981 | unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info()); |
| 1982 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| 1983 | ? elfcpp::R_386_TLS_TPOFF32 |
| 1984 | : elfcpp::R_386_TLS_TPOFF); |
| 1985 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 1986 | rel_dyn->add_local(object, r_sym, dyn_r_type, output_section, |
| 1987 | data_shndx, reloc.get_r_offset()); |
| 1988 | } |
| 1989 | break; |
| 1990 | |
| 1991 | default: |
| 1992 | gold_unreachable(); |
| 1993 | } |
| 1994 | } |
| 1995 | break; |
| 1996 | |
| 1997 | case elfcpp::R_386_32PLT: |
| 1998 | case elfcpp::R_386_TLS_GD_32: |
| 1999 | case elfcpp::R_386_TLS_GD_PUSH: |
| 2000 | case elfcpp::R_386_TLS_GD_CALL: |
| 2001 | case elfcpp::R_386_TLS_GD_POP: |
| 2002 | case elfcpp::R_386_TLS_LDM_32: |
| 2003 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 2004 | case elfcpp::R_386_TLS_LDM_CALL: |
| 2005 | case elfcpp::R_386_TLS_LDM_POP: |
| 2006 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 2007 | default: |
| 2008 | unsupported_reloc_local(object, r_type); |
| 2009 | break; |
| 2010 | } |
| 2011 | } |
| 2012 | |
| 2013 | // Report an unsupported relocation against a global symbol. |
| 2014 | |
| 2015 | void |
| 2016 | Target_i386::Scan::unsupported_reloc_global( |
| 2017 | Sized_relobj_file<32, false>* object, |
| 2018 | unsigned int r_type, |
| 2019 | Symbol* gsym) |
| 2020 | { |
| 2021 | gold_error(_("%s: unsupported reloc %u against global symbol %s"), |
| 2022 | object->name().c_str(), r_type, gsym->demangled_name().c_str()); |
| 2023 | } |
| 2024 | |
| 2025 | inline bool |
| 2026 | Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type) |
| 2027 | { |
| 2028 | switch (r_type) |
| 2029 | { |
| 2030 | case elfcpp::R_386_32: |
| 2031 | case elfcpp::R_386_16: |
| 2032 | case elfcpp::R_386_8: |
| 2033 | case elfcpp::R_386_GOTOFF: |
| 2034 | case elfcpp::R_386_GOT32: |
| 2035 | { |
| 2036 | return true; |
| 2037 | } |
| 2038 | default: |
| 2039 | return false; |
| 2040 | } |
| 2041 | return false; |
| 2042 | } |
| 2043 | |
| 2044 | inline bool |
| 2045 | Target_i386::Scan::local_reloc_may_be_function_pointer( |
| 2046 | Symbol_table* , |
| 2047 | Layout* , |
| 2048 | Target_i386* , |
| 2049 | Sized_relobj_file<32, false>* , |
| 2050 | unsigned int , |
| 2051 | Output_section* , |
| 2052 | const elfcpp::Rel<32, false>& , |
| 2053 | unsigned int r_type, |
| 2054 | const elfcpp::Sym<32, false>&) |
| 2055 | { |
| 2056 | return possible_function_pointer_reloc(r_type); |
| 2057 | } |
| 2058 | |
| 2059 | inline bool |
| 2060 | Target_i386::Scan::global_reloc_may_be_function_pointer( |
| 2061 | Symbol_table* , |
| 2062 | Layout* , |
| 2063 | Target_i386* , |
| 2064 | Sized_relobj_file<32, false>* , |
| 2065 | unsigned int , |
| 2066 | Output_section* , |
| 2067 | const elfcpp::Rel<32, false>& , |
| 2068 | unsigned int r_type, |
| 2069 | Symbol*) |
| 2070 | { |
| 2071 | return possible_function_pointer_reloc(r_type); |
| 2072 | } |
| 2073 | |
| 2074 | // Scan a relocation for a global symbol. |
| 2075 | |
| 2076 | inline void |
| 2077 | Target_i386::Scan::global(Symbol_table* symtab, |
| 2078 | Layout* layout, |
| 2079 | Target_i386* target, |
| 2080 | Sized_relobj_file<32, false>* object, |
| 2081 | unsigned int data_shndx, |
| 2082 | Output_section* output_section, |
| 2083 | const elfcpp::Rel<32, false>& reloc, |
| 2084 | unsigned int r_type, |
| 2085 | Symbol* gsym) |
| 2086 | { |
| 2087 | // A STT_GNU_IFUNC symbol may require a PLT entry. |
| 2088 | if (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 2089 | && this->reloc_needs_plt_for_ifunc(object, r_type)) |
| 2090 | target->make_plt_entry(symtab, layout, gsym); |
| 2091 | |
| 2092 | switch (r_type) |
| 2093 | { |
| 2094 | case elfcpp::R_386_NONE: |
| 2095 | case elfcpp::R_386_GNU_VTINHERIT: |
| 2096 | case elfcpp::R_386_GNU_VTENTRY: |
| 2097 | break; |
| 2098 | |
| 2099 | case elfcpp::R_386_32: |
| 2100 | case elfcpp::R_386_16: |
| 2101 | case elfcpp::R_386_8: |
| 2102 | { |
| 2103 | // Make a PLT entry if necessary. |
| 2104 | if (gsym->needs_plt_entry()) |
| 2105 | { |
| 2106 | target->make_plt_entry(symtab, layout, gsym); |
| 2107 | // Since this is not a PC-relative relocation, we may be |
| 2108 | // taking the address of a function. In that case we need to |
| 2109 | // set the entry in the dynamic symbol table to the address of |
| 2110 | // the PLT entry. |
| 2111 | if (gsym->is_from_dynobj() && !parameters->options().shared()) |
| 2112 | gsym->set_needs_dynsym_value(); |
| 2113 | } |
| 2114 | // Make a dynamic relocation if necessary. |
| 2115 | if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) |
| 2116 | { |
| 2117 | if (gsym->may_need_copy_reloc()) |
| 2118 | { |
| 2119 | target->copy_reloc(symtab, layout, object, |
| 2120 | data_shndx, output_section, gsym, reloc); |
| 2121 | } |
| 2122 | else if (r_type == elfcpp::R_386_32 |
| 2123 | && gsym->type() == elfcpp::STT_GNU_IFUNC |
| 2124 | && gsym->can_use_relative_reloc(false) |
| 2125 | && !gsym->is_from_dynobj() |
| 2126 | && !gsym->is_undefined() |
| 2127 | && !gsym->is_preemptible()) |
| 2128 | { |
| 2129 | // Use an IRELATIVE reloc for a locally defined |
| 2130 | // STT_GNU_IFUNC symbol. This makes a function |
| 2131 | // address in a PIE executable match the address in a |
| 2132 | // shared library that it links against. |
| 2133 | Reloc_section* rel_dyn = target->rel_irelative_section(layout); |
| 2134 | rel_dyn->add_symbolless_global_addend(gsym, |
| 2135 | elfcpp::R_386_IRELATIVE, |
| 2136 | output_section, |
| 2137 | object, data_shndx, |
| 2138 | reloc.get_r_offset()); |
| 2139 | } |
| 2140 | else if (r_type == elfcpp::R_386_32 |
| 2141 | && gsym->can_use_relative_reloc(false)) |
| 2142 | { |
| 2143 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 2144 | rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| 2145 | output_section, object, |
| 2146 | data_shndx, reloc.get_r_offset()); |
| 2147 | } |
| 2148 | else |
| 2149 | { |
| 2150 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 2151 | rel_dyn->add_global(gsym, r_type, output_section, object, |
| 2152 | data_shndx, reloc.get_r_offset()); |
| 2153 | } |
| 2154 | } |
| 2155 | } |
| 2156 | break; |
| 2157 | |
| 2158 | case elfcpp::R_386_PC32: |
| 2159 | case elfcpp::R_386_PC16: |
| 2160 | case elfcpp::R_386_PC8: |
| 2161 | { |
| 2162 | // Make a PLT entry if necessary. |
| 2163 | if (gsym->needs_plt_entry()) |
| 2164 | { |
| 2165 | // These relocations are used for function calls only in |
| 2166 | // non-PIC code. For a 32-bit relocation in a shared library, |
| 2167 | // we'll need a text relocation anyway, so we can skip the |
| 2168 | // PLT entry and let the dynamic linker bind the call directly |
| 2169 | // to the target. For smaller relocations, we should use a |
| 2170 | // PLT entry to ensure that the call can reach. |
| 2171 | if (!parameters->options().shared() |
| 2172 | || r_type != elfcpp::R_386_PC32) |
| 2173 | target->make_plt_entry(symtab, layout, gsym); |
| 2174 | } |
| 2175 | // Make a dynamic relocation if necessary. |
| 2176 | if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))) |
| 2177 | { |
| 2178 | if (gsym->may_need_copy_reloc()) |
| 2179 | { |
| 2180 | target->copy_reloc(symtab, layout, object, |
| 2181 | data_shndx, output_section, gsym, reloc); |
| 2182 | } |
| 2183 | else |
| 2184 | { |
| 2185 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 2186 | rel_dyn->add_global(gsym, r_type, output_section, object, |
| 2187 | data_shndx, reloc.get_r_offset()); |
| 2188 | } |
| 2189 | } |
| 2190 | } |
| 2191 | break; |
| 2192 | |
| 2193 | case elfcpp::R_386_GOT32: |
| 2194 | { |
| 2195 | // The symbol requires a GOT entry. |
| 2196 | Output_data_got<32, false>* got = target->got_section(symtab, layout); |
| 2197 | if (gsym->final_value_is_known()) |
| 2198 | { |
| 2199 | // For a STT_GNU_IFUNC symbol we want the PLT address. |
| 2200 | if (gsym->type() == elfcpp::STT_GNU_IFUNC) |
| 2201 | got->add_global_plt(gsym, GOT_TYPE_STANDARD); |
| 2202 | else |
| 2203 | got->add_global(gsym, GOT_TYPE_STANDARD); |
| 2204 | } |
| 2205 | else |
| 2206 | { |
| 2207 | // If this symbol is not fully resolved, we need to add a |
| 2208 | // GOT entry with a dynamic relocation. |
| 2209 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 2210 | |
| 2211 | // Use a GLOB_DAT rather than a RELATIVE reloc if: |
| 2212 | // |
| 2213 | // 1) The symbol may be defined in some other module. |
| 2214 | // |
| 2215 | // 2) We are building a shared library and this is a |
| 2216 | // protected symbol; using GLOB_DAT means that the dynamic |
| 2217 | // linker can use the address of the PLT in the main |
| 2218 | // executable when appropriate so that function address |
| 2219 | // comparisons work. |
| 2220 | // |
| 2221 | // 3) This is a STT_GNU_IFUNC symbol in position dependent |
| 2222 | // code, again so that function address comparisons work. |
| 2223 | if (gsym->is_from_dynobj() |
| 2224 | || gsym->is_undefined() |
| 2225 | || gsym->is_preemptible() |
| 2226 | || (gsym->visibility() == elfcpp::STV_PROTECTED |
| 2227 | && parameters->options().shared()) |
| 2228 | || (gsym->type() == elfcpp::STT_GNU_IFUNC |
| 2229 | && parameters->options().output_is_position_independent())) |
| 2230 | got->add_global_with_rel(gsym, GOT_TYPE_STANDARD, |
| 2231 | rel_dyn, elfcpp::R_386_GLOB_DAT); |
| 2232 | else |
| 2233 | { |
| 2234 | // For a STT_GNU_IFUNC symbol we want to write the PLT |
| 2235 | // offset into the GOT, so that function pointer |
| 2236 | // comparisons work correctly. |
| 2237 | bool is_new; |
| 2238 | if (gsym->type() != elfcpp::STT_GNU_IFUNC) |
| 2239 | is_new = got->add_global(gsym, GOT_TYPE_STANDARD); |
| 2240 | else |
| 2241 | { |
| 2242 | is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD); |
| 2243 | // Tell the dynamic linker to use the PLT address |
| 2244 | // when resolving relocations. |
| 2245 | if (gsym->is_from_dynobj() |
| 2246 | && !parameters->options().shared()) |
| 2247 | gsym->set_needs_dynsym_value(); |
| 2248 | } |
| 2249 | if (is_new) |
| 2250 | { |
| 2251 | unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD); |
| 2252 | rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| 2253 | got, got_off); |
| 2254 | } |
| 2255 | } |
| 2256 | } |
| 2257 | } |
| 2258 | break; |
| 2259 | |
| 2260 | case elfcpp::R_386_PLT32: |
| 2261 | // If the symbol is fully resolved, this is just a PC32 reloc. |
| 2262 | // Otherwise we need a PLT entry. |
| 2263 | if (gsym->final_value_is_known()) |
| 2264 | break; |
| 2265 | // If building a shared library, we can also skip the PLT entry |
| 2266 | // if the symbol is defined in the output file and is protected |
| 2267 | // or hidden. |
| 2268 | if (gsym->is_defined() |
| 2269 | && !gsym->is_from_dynobj() |
| 2270 | && !gsym->is_preemptible()) |
| 2271 | break; |
| 2272 | target->make_plt_entry(symtab, layout, gsym); |
| 2273 | break; |
| 2274 | |
| 2275 | case elfcpp::R_386_GOTOFF: |
| 2276 | case elfcpp::R_386_GOTPC: |
| 2277 | // We need a GOT section. |
| 2278 | target->got_section(symtab, layout); |
| 2279 | break; |
| 2280 | |
| 2281 | // These are relocations which should only be seen by the |
| 2282 | // dynamic linker, and should never be seen here. |
| 2283 | case elfcpp::R_386_COPY: |
| 2284 | case elfcpp::R_386_GLOB_DAT: |
| 2285 | case elfcpp::R_386_JUMP_SLOT: |
| 2286 | case elfcpp::R_386_RELATIVE: |
| 2287 | case elfcpp::R_386_IRELATIVE: |
| 2288 | case elfcpp::R_386_TLS_TPOFF: |
| 2289 | case elfcpp::R_386_TLS_DTPMOD32: |
| 2290 | case elfcpp::R_386_TLS_DTPOFF32: |
| 2291 | case elfcpp::R_386_TLS_TPOFF32: |
| 2292 | case elfcpp::R_386_TLS_DESC: |
| 2293 | gold_error(_("%s: unexpected reloc %u in object file"), |
| 2294 | object->name().c_str(), r_type); |
| 2295 | break; |
| 2296 | |
| 2297 | // These are initial tls relocs, which are expected when |
| 2298 | // linking. |
| 2299 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 2300 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 2301 | case elfcpp::R_386_TLS_DESC_CALL: |
| 2302 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 2303 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 2304 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 2305 | case elfcpp::R_386_TLS_IE_32: |
| 2306 | case elfcpp::R_386_TLS_GOTIE: |
| 2307 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 2308 | case elfcpp::R_386_TLS_LE_32: |
| 2309 | { |
| 2310 | const bool is_final = gsym->final_value_is_known(); |
| 2311 | const tls::Tls_optimization optimized_type |
| 2312 | = Target_i386::optimize_tls_reloc(is_final, r_type); |
| 2313 | switch (r_type) |
| 2314 | { |
| 2315 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 2316 | if (optimized_type == tls::TLSOPT_NONE) |
| 2317 | { |
| 2318 | // Create a pair of GOT entries for the module index and |
| 2319 | // dtv-relative offset. |
| 2320 | Output_data_got<32, false>* got |
| 2321 | = target->got_section(symtab, layout); |
| 2322 | got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR, |
| 2323 | target->rel_dyn_section(layout), |
| 2324 | elfcpp::R_386_TLS_DTPMOD32, |
| 2325 | elfcpp::R_386_TLS_DTPOFF32); |
| 2326 | } |
| 2327 | else if (optimized_type == tls::TLSOPT_TO_IE) |
| 2328 | { |
| 2329 | // Create a GOT entry for the tp-relative offset. |
| 2330 | Output_data_got<32, false>* got |
| 2331 | = target->got_section(symtab, layout); |
| 2332 | got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET, |
| 2333 | target->rel_dyn_section(layout), |
| 2334 | elfcpp::R_386_TLS_TPOFF); |
| 2335 | } |
| 2336 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 2337 | unsupported_reloc_global(object, r_type, gsym); |
| 2338 | break; |
| 2339 | |
| 2340 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (~oliva url) |
| 2341 | target->define_tls_base_symbol(symtab, layout); |
| 2342 | if (optimized_type == tls::TLSOPT_NONE) |
| 2343 | { |
| 2344 | // Create a double GOT entry with an R_386_TLS_DESC |
| 2345 | // reloc. The R_386_TLS_DESC reloc is resolved |
| 2346 | // lazily, so the GOT entry needs to be in an area in |
| 2347 | // .got.plt, not .got. Call got_section to make sure |
| 2348 | // the section has been created. |
| 2349 | target->got_section(symtab, layout); |
| 2350 | Output_data_got<32, false>* got = target->got_tlsdesc_section(); |
| 2351 | Reloc_section* rt = target->rel_tls_desc_section(layout); |
| 2352 | got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt, |
| 2353 | elfcpp::R_386_TLS_DESC, 0); |
| 2354 | } |
| 2355 | else if (optimized_type == tls::TLSOPT_TO_IE) |
| 2356 | { |
| 2357 | // Create a GOT entry for the tp-relative offset. |
| 2358 | Output_data_got<32, false>* got |
| 2359 | = target->got_section(symtab, layout); |
| 2360 | got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET, |
| 2361 | target->rel_dyn_section(layout), |
| 2362 | elfcpp::R_386_TLS_TPOFF); |
| 2363 | } |
| 2364 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 2365 | unsupported_reloc_global(object, r_type, gsym); |
| 2366 | break; |
| 2367 | |
| 2368 | case elfcpp::R_386_TLS_DESC_CALL: |
| 2369 | break; |
| 2370 | |
| 2371 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 2372 | if (optimized_type == tls::TLSOPT_NONE) |
| 2373 | { |
| 2374 | // Create a GOT entry for the module index. |
| 2375 | target->got_mod_index_entry(symtab, layout, object); |
| 2376 | } |
| 2377 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 2378 | unsupported_reloc_global(object, r_type, gsym); |
| 2379 | break; |
| 2380 | |
| 2381 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 2382 | break; |
| 2383 | |
| 2384 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 2385 | case elfcpp::R_386_TLS_IE_32: |
| 2386 | case elfcpp::R_386_TLS_GOTIE: |
| 2387 | layout->set_has_static_tls(); |
| 2388 | if (optimized_type == tls::TLSOPT_NONE) |
| 2389 | { |
| 2390 | // For the R_386_TLS_IE relocation, we need to create a |
| 2391 | // dynamic relocation when building a shared library. |
| 2392 | if (r_type == elfcpp::R_386_TLS_IE |
| 2393 | && parameters->options().shared()) |
| 2394 | { |
| 2395 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 2396 | rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE, |
| 2397 | output_section, object, |
| 2398 | data_shndx, |
| 2399 | reloc.get_r_offset()); |
| 2400 | } |
| 2401 | // Create a GOT entry for the tp-relative offset. |
| 2402 | Output_data_got<32, false>* got |
| 2403 | = target->got_section(symtab, layout); |
| 2404 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 2405 | ? elfcpp::R_386_TLS_TPOFF32 |
| 2406 | : elfcpp::R_386_TLS_TPOFF); |
| 2407 | unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 2408 | ? GOT_TYPE_TLS_OFFSET |
| 2409 | : GOT_TYPE_TLS_NOFFSET); |
| 2410 | got->add_global_with_rel(gsym, got_type, |
| 2411 | target->rel_dyn_section(layout), |
| 2412 | dyn_r_type); |
| 2413 | } |
| 2414 | else if (optimized_type != tls::TLSOPT_TO_LE) |
| 2415 | unsupported_reloc_global(object, r_type, gsym); |
| 2416 | break; |
| 2417 | |
| 2418 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 2419 | case elfcpp::R_386_TLS_LE_32: |
| 2420 | layout->set_has_static_tls(); |
| 2421 | if (parameters->options().shared()) |
| 2422 | { |
| 2423 | // We need to create a dynamic relocation. |
| 2424 | unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32 |
| 2425 | ? elfcpp::R_386_TLS_TPOFF32 |
| 2426 | : elfcpp::R_386_TLS_TPOFF); |
| 2427 | Reloc_section* rel_dyn = target->rel_dyn_section(layout); |
| 2428 | rel_dyn->add_global(gsym, dyn_r_type, output_section, object, |
| 2429 | data_shndx, reloc.get_r_offset()); |
| 2430 | } |
| 2431 | break; |
| 2432 | |
| 2433 | default: |
| 2434 | gold_unreachable(); |
| 2435 | } |
| 2436 | } |
| 2437 | break; |
| 2438 | |
| 2439 | case elfcpp::R_386_32PLT: |
| 2440 | case elfcpp::R_386_TLS_GD_32: |
| 2441 | case elfcpp::R_386_TLS_GD_PUSH: |
| 2442 | case elfcpp::R_386_TLS_GD_CALL: |
| 2443 | case elfcpp::R_386_TLS_GD_POP: |
| 2444 | case elfcpp::R_386_TLS_LDM_32: |
| 2445 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 2446 | case elfcpp::R_386_TLS_LDM_CALL: |
| 2447 | case elfcpp::R_386_TLS_LDM_POP: |
| 2448 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 2449 | default: |
| 2450 | unsupported_reloc_global(object, r_type, gsym); |
| 2451 | break; |
| 2452 | } |
| 2453 | } |
| 2454 | |
| 2455 | // Process relocations for gc. |
| 2456 | |
| 2457 | void |
| 2458 | Target_i386::gc_process_relocs(Symbol_table* symtab, |
| 2459 | Layout* layout, |
| 2460 | Sized_relobj_file<32, false>* object, |
| 2461 | unsigned int data_shndx, |
| 2462 | unsigned int, |
| 2463 | const unsigned char* prelocs, |
| 2464 | size_t reloc_count, |
| 2465 | Output_section* output_section, |
| 2466 | bool needs_special_offset_handling, |
| 2467 | size_t local_symbol_count, |
| 2468 | const unsigned char* plocal_symbols) |
| 2469 | { |
| 2470 | gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL, |
| 2471 | Target_i386::Scan, |
| 2472 | Target_i386::Relocatable_size_for_reloc>( |
| 2473 | symtab, |
| 2474 | layout, |
| 2475 | this, |
| 2476 | object, |
| 2477 | data_shndx, |
| 2478 | prelocs, |
| 2479 | reloc_count, |
| 2480 | output_section, |
| 2481 | needs_special_offset_handling, |
| 2482 | local_symbol_count, |
| 2483 | plocal_symbols); |
| 2484 | } |
| 2485 | |
| 2486 | // Scan relocations for a section. |
| 2487 | |
| 2488 | void |
| 2489 | Target_i386::scan_relocs(Symbol_table* symtab, |
| 2490 | Layout* layout, |
| 2491 | Sized_relobj_file<32, false>* object, |
| 2492 | unsigned int data_shndx, |
| 2493 | unsigned int sh_type, |
| 2494 | const unsigned char* prelocs, |
| 2495 | size_t reloc_count, |
| 2496 | Output_section* output_section, |
| 2497 | bool needs_special_offset_handling, |
| 2498 | size_t local_symbol_count, |
| 2499 | const unsigned char* plocal_symbols) |
| 2500 | { |
| 2501 | if (sh_type == elfcpp::SHT_RELA) |
| 2502 | { |
| 2503 | gold_error(_("%s: unsupported RELA reloc section"), |
| 2504 | object->name().c_str()); |
| 2505 | return; |
| 2506 | } |
| 2507 | |
| 2508 | gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL, |
| 2509 | Target_i386::Scan>( |
| 2510 | symtab, |
| 2511 | layout, |
| 2512 | this, |
| 2513 | object, |
| 2514 | data_shndx, |
| 2515 | prelocs, |
| 2516 | reloc_count, |
| 2517 | output_section, |
| 2518 | needs_special_offset_handling, |
| 2519 | local_symbol_count, |
| 2520 | plocal_symbols); |
| 2521 | } |
| 2522 | |
| 2523 | // Finalize the sections. |
| 2524 | |
| 2525 | void |
| 2526 | Target_i386::do_finalize_sections( |
| 2527 | Layout* layout, |
| 2528 | const Input_objects*, |
| 2529 | Symbol_table* symtab) |
| 2530 | { |
| 2531 | const Reloc_section* rel_plt = (this->plt_ == NULL |
| 2532 | ? NULL |
| 2533 | : this->plt_->rel_plt()); |
| 2534 | layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt, |
| 2535 | this->rel_dyn_, true, false); |
| 2536 | |
| 2537 | // Emit any relocs we saved in an attempt to avoid generating COPY |
| 2538 | // relocs. |
| 2539 | if (this->copy_relocs_.any_saved_relocs()) |
| 2540 | this->copy_relocs_.emit(this->rel_dyn_section(layout)); |
| 2541 | |
| 2542 | // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of |
| 2543 | // the .got.plt section. |
| 2544 | Symbol* sym = this->global_offset_table_; |
| 2545 | if (sym != NULL) |
| 2546 | { |
| 2547 | uint32_t data_size = this->got_plt_->current_data_size(); |
| 2548 | symtab->get_sized_symbol<32>(sym)->set_symsize(data_size); |
| 2549 | } |
| 2550 | |
| 2551 | if (parameters->doing_static_link() |
| 2552 | && (this->plt_ == NULL || !this->plt_->has_irelative_section())) |
| 2553 | { |
| 2554 | // If linking statically, make sure that the __rel_iplt symbols |
| 2555 | // were defined if necessary, even if we didn't create a PLT. |
| 2556 | static const Define_symbol_in_segment syms[] = |
| 2557 | { |
| 2558 | { |
| 2559 | "__rel_iplt_start", // name |
| 2560 | elfcpp::PT_LOAD, // segment_type |
| 2561 | elfcpp::PF_W, // segment_flags_set |
| 2562 | elfcpp::PF(0), // segment_flags_clear |
| 2563 | 0, // value |
| 2564 | 0, // size |
| 2565 | elfcpp::STT_NOTYPE, // type |
| 2566 | elfcpp::STB_GLOBAL, // binding |
| 2567 | elfcpp::STV_HIDDEN, // visibility |
| 2568 | 0, // nonvis |
| 2569 | Symbol::SEGMENT_START, // offset_from_base |
| 2570 | true // only_if_ref |
| 2571 | }, |
| 2572 | { |
| 2573 | "__rel_iplt_end", // name |
| 2574 | elfcpp::PT_LOAD, // segment_type |
| 2575 | elfcpp::PF_W, // segment_flags_set |
| 2576 | elfcpp::PF(0), // segment_flags_clear |
| 2577 | 0, // value |
| 2578 | 0, // size |
| 2579 | elfcpp::STT_NOTYPE, // type |
| 2580 | elfcpp::STB_GLOBAL, // binding |
| 2581 | elfcpp::STV_HIDDEN, // visibility |
| 2582 | 0, // nonvis |
| 2583 | Symbol::SEGMENT_START, // offset_from_base |
| 2584 | true // only_if_ref |
| 2585 | } |
| 2586 | }; |
| 2587 | |
| 2588 | symtab->define_symbols(layout, 2, syms, |
| 2589 | layout->script_options()->saw_sections_clause()); |
| 2590 | } |
| 2591 | } |
| 2592 | |
| 2593 | // Return whether a direct absolute static relocation needs to be applied. |
| 2594 | // In cases where Scan::local() or Scan::global() has created |
| 2595 | // a dynamic relocation other than R_386_RELATIVE, the addend |
| 2596 | // of the relocation is carried in the data, and we must not |
| 2597 | // apply the static relocation. |
| 2598 | |
| 2599 | inline bool |
| 2600 | Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym, |
| 2601 | unsigned int r_type, |
| 2602 | bool is_32bit, |
| 2603 | Output_section* output_section) |
| 2604 | { |
| 2605 | // If the output section is not allocated, then we didn't call |
| 2606 | // scan_relocs, we didn't create a dynamic reloc, and we must apply |
| 2607 | // the reloc here. |
| 2608 | if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0) |
| 2609 | return true; |
| 2610 | |
| 2611 | int ref_flags = Scan::get_reference_flags(r_type); |
| 2612 | |
| 2613 | // For local symbols, we will have created a non-RELATIVE dynamic |
| 2614 | // relocation only if (a) the output is position independent, |
| 2615 | // (b) the relocation is absolute (not pc- or segment-relative), and |
| 2616 | // (c) the relocation is not 32 bits wide. |
| 2617 | if (gsym == NULL) |
| 2618 | return !(parameters->options().output_is_position_independent() |
| 2619 | && (ref_flags & Symbol::ABSOLUTE_REF) |
| 2620 | && !is_32bit); |
| 2621 | |
| 2622 | // For global symbols, we use the same helper routines used in the |
| 2623 | // scan pass. If we did not create a dynamic relocation, or if we |
| 2624 | // created a RELATIVE dynamic relocation, we should apply the static |
| 2625 | // relocation. |
| 2626 | bool has_dyn = gsym->needs_dynamic_reloc(ref_flags); |
| 2627 | bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF) |
| 2628 | && gsym->can_use_relative_reloc(ref_flags |
| 2629 | & Symbol::FUNCTION_CALL); |
| 2630 | return !has_dyn || is_rel; |
| 2631 | } |
| 2632 | |
| 2633 | // Perform a relocation. |
| 2634 | |
| 2635 | inline bool |
| 2636 | Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo, |
| 2637 | Target_i386* target, |
| 2638 | Output_section* output_section, |
| 2639 | size_t relnum, |
| 2640 | const elfcpp::Rel<32, false>& rel, |
| 2641 | unsigned int r_type, |
| 2642 | const Sized_symbol<32>* gsym, |
| 2643 | const Symbol_value<32>* psymval, |
| 2644 | unsigned char* view, |
| 2645 | elfcpp::Elf_types<32>::Elf_Addr address, |
| 2646 | section_size_type view_size) |
| 2647 | { |
| 2648 | if (this->skip_call_tls_get_addr_) |
| 2649 | { |
| 2650 | if ((r_type != elfcpp::R_386_PLT32 |
| 2651 | && r_type != elfcpp::R_386_PC32) |
| 2652 | || gsym == NULL |
| 2653 | || strcmp(gsym->name(), "___tls_get_addr") != 0) |
| 2654 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2655 | _("missing expected TLS relocation")); |
| 2656 | else |
| 2657 | { |
| 2658 | this->skip_call_tls_get_addr_ = false; |
| 2659 | return false; |
| 2660 | } |
| 2661 | } |
| 2662 | |
| 2663 | if (view == NULL) |
| 2664 | return true; |
| 2665 | |
| 2666 | const Sized_relobj_file<32, false>* object = relinfo->object; |
| 2667 | |
| 2668 | // Pick the value to use for symbols defined in shared objects. |
| 2669 | Symbol_value<32> symval; |
| 2670 | if (gsym != NULL |
| 2671 | && gsym->type() == elfcpp::STT_GNU_IFUNC |
| 2672 | && r_type == elfcpp::R_386_32 |
| 2673 | && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)) |
| 2674 | && gsym->can_use_relative_reloc(false) |
| 2675 | && !gsym->is_from_dynobj() |
| 2676 | && !gsym->is_undefined() |
| 2677 | && !gsym->is_preemptible()) |
| 2678 | { |
| 2679 | // In this case we are generating a R_386_IRELATIVE reloc. We |
| 2680 | // want to use the real value of the symbol, not the PLT offset. |
| 2681 | } |
| 2682 | else if (gsym != NULL |
| 2683 | && gsym->use_plt_offset(Scan::get_reference_flags(r_type))) |
| 2684 | { |
| 2685 | symval.set_output_value(target->plt_address_for_global(gsym)); |
| 2686 | psymval = &symval; |
| 2687 | } |
| 2688 | else if (gsym == NULL && psymval->is_ifunc_symbol()) |
| 2689 | { |
| 2690 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2691 | if (object->local_has_plt_offset(r_sym)) |
| 2692 | { |
| 2693 | symval.set_output_value(target->plt_address_for_local(object, r_sym)); |
| 2694 | psymval = &symval; |
| 2695 | } |
| 2696 | } |
| 2697 | |
| 2698 | // Get the GOT offset if needed. |
| 2699 | // The GOT pointer points to the end of the GOT section. |
| 2700 | // We need to subtract the size of the GOT section to get |
| 2701 | // the actual offset to use in the relocation. |
| 2702 | bool have_got_offset = false; |
| 2703 | unsigned int got_offset = 0; |
| 2704 | switch (r_type) |
| 2705 | { |
| 2706 | case elfcpp::R_386_GOT32: |
| 2707 | if (gsym != NULL) |
| 2708 | { |
| 2709 | gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD)); |
| 2710 | got_offset = (gsym->got_offset(GOT_TYPE_STANDARD) |
| 2711 | - target->got_size()); |
| 2712 | } |
| 2713 | else |
| 2714 | { |
| 2715 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2716 | gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD)); |
| 2717 | got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD) |
| 2718 | - target->got_size()); |
| 2719 | } |
| 2720 | have_got_offset = true; |
| 2721 | break; |
| 2722 | |
| 2723 | default: |
| 2724 | break; |
| 2725 | } |
| 2726 | |
| 2727 | switch (r_type) |
| 2728 | { |
| 2729 | case elfcpp::R_386_NONE: |
| 2730 | case elfcpp::R_386_GNU_VTINHERIT: |
| 2731 | case elfcpp::R_386_GNU_VTENTRY: |
| 2732 | break; |
| 2733 | |
| 2734 | case elfcpp::R_386_32: |
| 2735 | if (should_apply_static_reloc(gsym, r_type, true, output_section)) |
| 2736 | Relocate_functions<32, false>::rel32(view, object, psymval); |
| 2737 | break; |
| 2738 | |
| 2739 | case elfcpp::R_386_PC32: |
| 2740 | if (should_apply_static_reloc(gsym, r_type, true, output_section)) |
| 2741 | Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| 2742 | break; |
| 2743 | |
| 2744 | case elfcpp::R_386_16: |
| 2745 | if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| 2746 | Relocate_functions<32, false>::rel16(view, object, psymval); |
| 2747 | break; |
| 2748 | |
| 2749 | case elfcpp::R_386_PC16: |
| 2750 | if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| 2751 | Relocate_functions<32, false>::pcrel16(view, object, psymval, address); |
| 2752 | break; |
| 2753 | |
| 2754 | case elfcpp::R_386_8: |
| 2755 | if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| 2756 | Relocate_functions<32, false>::rel8(view, object, psymval); |
| 2757 | break; |
| 2758 | |
| 2759 | case elfcpp::R_386_PC8: |
| 2760 | if (should_apply_static_reloc(gsym, r_type, false, output_section)) |
| 2761 | Relocate_functions<32, false>::pcrel8(view, object, psymval, address); |
| 2762 | break; |
| 2763 | |
| 2764 | case elfcpp::R_386_PLT32: |
| 2765 | gold_assert(gsym == NULL |
| 2766 | || gsym->has_plt_offset() |
| 2767 | || gsym->final_value_is_known() |
| 2768 | || (gsym->is_defined() |
| 2769 | && !gsym->is_from_dynobj() |
| 2770 | && !gsym->is_preemptible())); |
| 2771 | Relocate_functions<32, false>::pcrel32(view, object, psymval, address); |
| 2772 | break; |
| 2773 | |
| 2774 | case elfcpp::R_386_GOT32: |
| 2775 | gold_assert(have_got_offset); |
| 2776 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2777 | break; |
| 2778 | |
| 2779 | case elfcpp::R_386_GOTOFF: |
| 2780 | { |
| 2781 | elfcpp::Elf_types<32>::Elf_Addr value; |
| 2782 | value = (psymval->value(object, 0) |
| 2783 | - target->got_plt_section()->address()); |
| 2784 | Relocate_functions<32, false>::rel32(view, value); |
| 2785 | } |
| 2786 | break; |
| 2787 | |
| 2788 | case elfcpp::R_386_GOTPC: |
| 2789 | { |
| 2790 | elfcpp::Elf_types<32>::Elf_Addr value; |
| 2791 | value = target->got_plt_section()->address(); |
| 2792 | Relocate_functions<32, false>::pcrel32(view, value, address); |
| 2793 | } |
| 2794 | break; |
| 2795 | |
| 2796 | case elfcpp::R_386_COPY: |
| 2797 | case elfcpp::R_386_GLOB_DAT: |
| 2798 | case elfcpp::R_386_JUMP_SLOT: |
| 2799 | case elfcpp::R_386_RELATIVE: |
| 2800 | case elfcpp::R_386_IRELATIVE: |
| 2801 | // These are outstanding tls relocs, which are unexpected when |
| 2802 | // linking. |
| 2803 | case elfcpp::R_386_TLS_TPOFF: |
| 2804 | case elfcpp::R_386_TLS_DTPMOD32: |
| 2805 | case elfcpp::R_386_TLS_DTPOFF32: |
| 2806 | case elfcpp::R_386_TLS_TPOFF32: |
| 2807 | case elfcpp::R_386_TLS_DESC: |
| 2808 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2809 | _("unexpected reloc %u in object file"), |
| 2810 | r_type); |
| 2811 | break; |
| 2812 | |
| 2813 | // These are initial tls relocs, which are expected when |
| 2814 | // linking. |
| 2815 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 2816 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 2817 | case elfcpp::R_386_TLS_DESC_CALL: |
| 2818 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 2819 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 2820 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 2821 | case elfcpp::R_386_TLS_IE_32: |
| 2822 | case elfcpp::R_386_TLS_GOTIE: |
| 2823 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 2824 | case elfcpp::R_386_TLS_LE_32: |
| 2825 | this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval, |
| 2826 | view, address, view_size); |
| 2827 | break; |
| 2828 | |
| 2829 | case elfcpp::R_386_32PLT: |
| 2830 | case elfcpp::R_386_TLS_GD_32: |
| 2831 | case elfcpp::R_386_TLS_GD_PUSH: |
| 2832 | case elfcpp::R_386_TLS_GD_CALL: |
| 2833 | case elfcpp::R_386_TLS_GD_POP: |
| 2834 | case elfcpp::R_386_TLS_LDM_32: |
| 2835 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 2836 | case elfcpp::R_386_TLS_LDM_CALL: |
| 2837 | case elfcpp::R_386_TLS_LDM_POP: |
| 2838 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 2839 | default: |
| 2840 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2841 | _("unsupported reloc %u"), |
| 2842 | r_type); |
| 2843 | break; |
| 2844 | } |
| 2845 | |
| 2846 | return true; |
| 2847 | } |
| 2848 | |
| 2849 | // Perform a TLS relocation. |
| 2850 | |
| 2851 | inline void |
| 2852 | Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo, |
| 2853 | Target_i386* target, |
| 2854 | size_t relnum, |
| 2855 | const elfcpp::Rel<32, false>& rel, |
| 2856 | unsigned int r_type, |
| 2857 | const Sized_symbol<32>* gsym, |
| 2858 | const Symbol_value<32>* psymval, |
| 2859 | unsigned char* view, |
| 2860 | elfcpp::Elf_types<32>::Elf_Addr, |
| 2861 | section_size_type view_size) |
| 2862 | { |
| 2863 | Output_segment* tls_segment = relinfo->layout->tls_segment(); |
| 2864 | |
| 2865 | const Sized_relobj_file<32, false>* object = relinfo->object; |
| 2866 | |
| 2867 | elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0); |
| 2868 | |
| 2869 | const bool is_final = (gsym == NULL |
| 2870 | ? !parameters->options().shared() |
| 2871 | : gsym->final_value_is_known()); |
| 2872 | const tls::Tls_optimization optimized_type |
| 2873 | = Target_i386::optimize_tls_reloc(is_final, r_type); |
| 2874 | switch (r_type) |
| 2875 | { |
| 2876 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 2877 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2878 | { |
| 2879 | if (tls_segment == NULL) |
| 2880 | { |
| 2881 | gold_assert(parameters->errors()->error_count() > 0 |
| 2882 | || issue_undefined_symbol_error(gsym)); |
| 2883 | return; |
| 2884 | } |
| 2885 | this->tls_gd_to_le(relinfo, relnum, tls_segment, |
| 2886 | rel, r_type, value, view, |
| 2887 | view_size); |
| 2888 | break; |
| 2889 | } |
| 2890 | else |
| 2891 | { |
| 2892 | unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE |
| 2893 | ? GOT_TYPE_TLS_NOFFSET |
| 2894 | : GOT_TYPE_TLS_PAIR); |
| 2895 | unsigned int got_offset; |
| 2896 | if (gsym != NULL) |
| 2897 | { |
| 2898 | gold_assert(gsym->has_got_offset(got_type)); |
| 2899 | got_offset = gsym->got_offset(got_type) - target->got_size(); |
| 2900 | } |
| 2901 | else |
| 2902 | { |
| 2903 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2904 | gold_assert(object->local_has_got_offset(r_sym, got_type)); |
| 2905 | got_offset = (object->local_got_offset(r_sym, got_type) |
| 2906 | - target->got_size()); |
| 2907 | } |
| 2908 | if (optimized_type == tls::TLSOPT_TO_IE) |
| 2909 | { |
| 2910 | this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type, |
| 2911 | got_offset, view, view_size); |
| 2912 | break; |
| 2913 | } |
| 2914 | else if (optimized_type == tls::TLSOPT_NONE) |
| 2915 | { |
| 2916 | // Relocate the field with the offset of the pair of GOT |
| 2917 | // entries. |
| 2918 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2919 | break; |
| 2920 | } |
| 2921 | } |
| 2922 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2923 | _("unsupported reloc %u"), |
| 2924 | r_type); |
| 2925 | break; |
| 2926 | |
| 2927 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 2928 | case elfcpp::R_386_TLS_DESC_CALL: |
| 2929 | this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU; |
| 2930 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 2931 | { |
| 2932 | if (tls_segment == NULL) |
| 2933 | { |
| 2934 | gold_assert(parameters->errors()->error_count() > 0 |
| 2935 | || issue_undefined_symbol_error(gsym)); |
| 2936 | return; |
| 2937 | } |
| 2938 | this->tls_desc_gd_to_le(relinfo, relnum, tls_segment, |
| 2939 | rel, r_type, value, view, |
| 2940 | view_size); |
| 2941 | break; |
| 2942 | } |
| 2943 | else |
| 2944 | { |
| 2945 | unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE |
| 2946 | ? GOT_TYPE_TLS_NOFFSET |
| 2947 | : GOT_TYPE_TLS_DESC); |
| 2948 | unsigned int got_offset = 0; |
| 2949 | if (r_type == elfcpp::R_386_TLS_GOTDESC |
| 2950 | && optimized_type == tls::TLSOPT_NONE) |
| 2951 | { |
| 2952 | // We created GOT entries in the .got.tlsdesc portion of |
| 2953 | // the .got.plt section, but the offset stored in the |
| 2954 | // symbol is the offset within .got.tlsdesc. |
| 2955 | got_offset = (target->got_size() |
| 2956 | + target->got_plt_section()->data_size()); |
| 2957 | } |
| 2958 | if (gsym != NULL) |
| 2959 | { |
| 2960 | gold_assert(gsym->has_got_offset(got_type)); |
| 2961 | got_offset += gsym->got_offset(got_type) - target->got_size(); |
| 2962 | } |
| 2963 | else |
| 2964 | { |
| 2965 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 2966 | gold_assert(object->local_has_got_offset(r_sym, got_type)); |
| 2967 | got_offset += (object->local_got_offset(r_sym, got_type) |
| 2968 | - target->got_size()); |
| 2969 | } |
| 2970 | if (optimized_type == tls::TLSOPT_TO_IE) |
| 2971 | { |
| 2972 | if (tls_segment == NULL) |
| 2973 | { |
| 2974 | gold_assert(parameters->errors()->error_count() > 0 |
| 2975 | || issue_undefined_symbol_error(gsym)); |
| 2976 | return; |
| 2977 | } |
| 2978 | this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type, |
| 2979 | got_offset, view, view_size); |
| 2980 | break; |
| 2981 | } |
| 2982 | else if (optimized_type == tls::TLSOPT_NONE) |
| 2983 | { |
| 2984 | if (r_type == elfcpp::R_386_TLS_GOTDESC) |
| 2985 | { |
| 2986 | // Relocate the field with the offset of the pair of GOT |
| 2987 | // entries. |
| 2988 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 2989 | } |
| 2990 | break; |
| 2991 | } |
| 2992 | } |
| 2993 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 2994 | _("unsupported reloc %u"), |
| 2995 | r_type); |
| 2996 | break; |
| 2997 | |
| 2998 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 2999 | if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN) |
| 3000 | { |
| 3001 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 3002 | _("both SUN and GNU model " |
| 3003 | "TLS relocations")); |
| 3004 | break; |
| 3005 | } |
| 3006 | this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU; |
| 3007 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 3008 | { |
| 3009 | if (tls_segment == NULL) |
| 3010 | { |
| 3011 | gold_assert(parameters->errors()->error_count() > 0 |
| 3012 | || issue_undefined_symbol_error(gsym)); |
| 3013 | return; |
| 3014 | } |
| 3015 | this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type, |
| 3016 | value, view, view_size); |
| 3017 | break; |
| 3018 | } |
| 3019 | else if (optimized_type == tls::TLSOPT_NONE) |
| 3020 | { |
| 3021 | // Relocate the field with the offset of the GOT entry for |
| 3022 | // the module index. |
| 3023 | unsigned int got_offset; |
| 3024 | got_offset = (target->got_mod_index_entry(NULL, NULL, NULL) |
| 3025 | - target->got_size()); |
| 3026 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 3027 | break; |
| 3028 | } |
| 3029 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 3030 | _("unsupported reloc %u"), |
| 3031 | r_type); |
| 3032 | break; |
| 3033 | |
| 3034 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 3035 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 3036 | { |
| 3037 | // This reloc can appear in debugging sections, in which |
| 3038 | // case we must not convert to local-exec. We decide what |
| 3039 | // to do based on whether the section is marked as |
| 3040 | // containing executable code. That is what the GNU linker |
| 3041 | // does as well. |
| 3042 | elfcpp::Shdr<32, false> shdr(relinfo->data_shdr); |
| 3043 | if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0) |
| 3044 | { |
| 3045 | if (tls_segment == NULL) |
| 3046 | { |
| 3047 | gold_assert(parameters->errors()->error_count() > 0 |
| 3048 | || issue_undefined_symbol_error(gsym)); |
| 3049 | return; |
| 3050 | } |
| 3051 | value -= tls_segment->memsz(); |
| 3052 | } |
| 3053 | } |
| 3054 | Relocate_functions<32, false>::rel32(view, value); |
| 3055 | break; |
| 3056 | |
| 3057 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 3058 | case elfcpp::R_386_TLS_GOTIE: |
| 3059 | case elfcpp::R_386_TLS_IE_32: |
| 3060 | if (optimized_type == tls::TLSOPT_TO_LE) |
| 3061 | { |
| 3062 | if (tls_segment == NULL) |
| 3063 | { |
| 3064 | gold_assert(parameters->errors()->error_count() > 0 |
| 3065 | || issue_undefined_symbol_error(gsym)); |
| 3066 | return; |
| 3067 | } |
| 3068 | Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment, |
| 3069 | rel, r_type, value, view, |
| 3070 | view_size); |
| 3071 | break; |
| 3072 | } |
| 3073 | else if (optimized_type == tls::TLSOPT_NONE) |
| 3074 | { |
| 3075 | // Relocate the field with the offset of the GOT entry for |
| 3076 | // the tp-relative offset of the symbol. |
| 3077 | unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32 |
| 3078 | ? GOT_TYPE_TLS_OFFSET |
| 3079 | : GOT_TYPE_TLS_NOFFSET); |
| 3080 | unsigned int got_offset; |
| 3081 | if (gsym != NULL) |
| 3082 | { |
| 3083 | gold_assert(gsym->has_got_offset(got_type)); |
| 3084 | got_offset = gsym->got_offset(got_type); |
| 3085 | } |
| 3086 | else |
| 3087 | { |
| 3088 | unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info()); |
| 3089 | gold_assert(object->local_has_got_offset(r_sym, got_type)); |
| 3090 | got_offset = object->local_got_offset(r_sym, got_type); |
| 3091 | } |
| 3092 | // For the R_386_TLS_IE relocation, we need to apply the |
| 3093 | // absolute address of the GOT entry. |
| 3094 | if (r_type == elfcpp::R_386_TLS_IE) |
| 3095 | got_offset += target->got_plt_section()->address(); |
| 3096 | // All GOT offsets are relative to the end of the GOT. |
| 3097 | got_offset -= target->got_size(); |
| 3098 | Relocate_functions<32, false>::rel32(view, got_offset); |
| 3099 | break; |
| 3100 | } |
| 3101 | gold_error_at_location(relinfo, relnum, rel.get_r_offset(), |
| 3102 | _("unsupported reloc %u"), |
| 3103 | r_type); |
| 3104 | break; |
| 3105 | |
| 3106 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 3107 | // If we're creating a shared library, a dynamic relocation will |
| 3108 | // have been created for this location, so do not apply it now. |
| 3109 | if (!parameters->options().shared()) |
| 3110 | { |
| 3111 | if (tls_segment == NULL) |
| 3112 | { |
| 3113 | gold_assert(parameters->errors()->error_count() > 0 |
| 3114 | || issue_undefined_symbol_error(gsym)); |
| 3115 | return; |
| 3116 | } |
| 3117 | value -= tls_segment->memsz(); |
| 3118 | Relocate_functions<32, false>::rel32(view, value); |
| 3119 | } |
| 3120 | break; |
| 3121 | |
| 3122 | case elfcpp::R_386_TLS_LE_32: |
| 3123 | // If we're creating a shared library, a dynamic relocation will |
| 3124 | // have been created for this location, so do not apply it now. |
| 3125 | if (!parameters->options().shared()) |
| 3126 | { |
| 3127 | if (tls_segment == NULL) |
| 3128 | { |
| 3129 | gold_assert(parameters->errors()->error_count() > 0 |
| 3130 | || issue_undefined_symbol_error(gsym)); |
| 3131 | return; |
| 3132 | } |
| 3133 | value = tls_segment->memsz() - value; |
| 3134 | Relocate_functions<32, false>::rel32(view, value); |
| 3135 | } |
| 3136 | break; |
| 3137 | } |
| 3138 | } |
| 3139 | |
| 3140 | // Do a relocation in which we convert a TLS General-Dynamic to a |
| 3141 | // Local-Exec. |
| 3142 | |
| 3143 | inline void |
| 3144 | Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo, |
| 3145 | size_t relnum, |
| 3146 | Output_segment* tls_segment, |
| 3147 | const elfcpp::Rel<32, false>& rel, |
| 3148 | unsigned int, |
| 3149 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 3150 | unsigned char* view, |
| 3151 | section_size_type view_size) |
| 3152 | { |
| 3153 | // leal foo(,%reg,1),%eax; call ___tls_get_addr |
| 3154 | // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| 3155 | // leal foo(%reg),%eax; call ___tls_get_addr |
| 3156 | // ==> movl %gs:0,%eax; subl $foo@tpoff,%eax |
| 3157 | |
| 3158 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3159 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| 3160 | |
| 3161 | unsigned char op1 = view[-1]; |
| 3162 | unsigned char op2 = view[-2]; |
| 3163 | |
| 3164 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3165 | op2 == 0x8d || op2 == 0x04); |
| 3166 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| 3167 | |
| 3168 | int roff = 5; |
| 3169 | |
| 3170 | if (op2 == 0x04) |
| 3171 | { |
| 3172 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3); |
| 3173 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d); |
| 3174 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3175 | ((op1 & 0xc7) == 0x05 && op1 != (4 << 3))); |
| 3176 | memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 3177 | } |
| 3178 | else |
| 3179 | { |
| 3180 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3181 | (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| 3182 | if (rel.get_r_offset() + 9 < view_size |
| 3183 | && view[9] == 0x90) |
| 3184 | { |
| 3185 | // There is a trailing nop. Use the size byte subl. |
| 3186 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 3187 | roff = 6; |
| 3188 | } |
| 3189 | else |
| 3190 | { |
| 3191 | // Use the five byte subl. |
| 3192 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| 3193 | } |
| 3194 | } |
| 3195 | |
| 3196 | value = tls_segment->memsz() - value; |
| 3197 | Relocate_functions<32, false>::rel32(view + roff, value); |
| 3198 | |
| 3199 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 3200 | // We can skip it. |
| 3201 | this->skip_call_tls_get_addr_ = true; |
| 3202 | } |
| 3203 | |
| 3204 | // Do a relocation in which we convert a TLS General-Dynamic to an |
| 3205 | // Initial-Exec. |
| 3206 | |
| 3207 | inline void |
| 3208 | Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo, |
| 3209 | size_t relnum, |
| 3210 | Output_segment*, |
| 3211 | const elfcpp::Rel<32, false>& rel, |
| 3212 | unsigned int, |
| 3213 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 3214 | unsigned char* view, |
| 3215 | section_size_type view_size) |
| 3216 | { |
| 3217 | // leal foo(,%ebx,1),%eax; call ___tls_get_addr |
| 3218 | // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax |
| 3219 | |
| 3220 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3221 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| 3222 | |
| 3223 | unsigned char op1 = view[-1]; |
| 3224 | unsigned char op2 = view[-2]; |
| 3225 | |
| 3226 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3227 | op2 == 0x8d || op2 == 0x04); |
| 3228 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| 3229 | |
| 3230 | int roff = 5; |
| 3231 | |
| 3232 | // FIXME: For now, support only the first (SIB) form. |
| 3233 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04); |
| 3234 | |
| 3235 | if (op2 == 0x04) |
| 3236 | { |
| 3237 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3); |
| 3238 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d); |
| 3239 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3240 | ((op1 & 0xc7) == 0x05 && op1 != (4 << 3))); |
| 3241 | memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12); |
| 3242 | } |
| 3243 | else |
| 3244 | { |
| 3245 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3246 | (op1 & 0xf8) == 0x80 && (op1 & 7) != 4); |
| 3247 | if (rel.get_r_offset() + 9 < view_size |
| 3248 | && view[9] == 0x90) |
| 3249 | { |
| 3250 | // FIXME: This is not the right instruction sequence. |
| 3251 | // There is a trailing nop. Use the size byte subl. |
| 3252 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12); |
| 3253 | roff = 6; |
| 3254 | } |
| 3255 | else |
| 3256 | { |
| 3257 | // FIXME: This is not the right instruction sequence. |
| 3258 | // Use the five byte subl. |
| 3259 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11); |
| 3260 | } |
| 3261 | } |
| 3262 | |
| 3263 | Relocate_functions<32, false>::rel32(view + roff, value); |
| 3264 | |
| 3265 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 3266 | // We can skip it. |
| 3267 | this->skip_call_tls_get_addr_ = true; |
| 3268 | } |
| 3269 | |
| 3270 | // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL |
| 3271 | // General-Dynamic to a Local-Exec. |
| 3272 | |
| 3273 | inline void |
| 3274 | Target_i386::Relocate::tls_desc_gd_to_le( |
| 3275 | const Relocate_info<32, false>* relinfo, |
| 3276 | size_t relnum, |
| 3277 | Output_segment* tls_segment, |
| 3278 | const elfcpp::Rel<32, false>& rel, |
| 3279 | unsigned int r_type, |
| 3280 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 3281 | unsigned char* view, |
| 3282 | section_size_type view_size) |
| 3283 | { |
| 3284 | if (r_type == elfcpp::R_386_TLS_GOTDESC) |
| 3285 | { |
| 3286 | // leal foo@TLSDESC(%ebx), %eax |
| 3287 | // ==> leal foo@NTPOFF, %eax |
| 3288 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3289 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 3290 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3291 | view[-2] == 0x8d && view[-1] == 0x83); |
| 3292 | view[-1] = 0x05; |
| 3293 | value -= tls_segment->memsz(); |
| 3294 | Relocate_functions<32, false>::rel32(view, value); |
| 3295 | } |
| 3296 | else |
| 3297 | { |
| 3298 | // call *foo@TLSCALL(%eax) |
| 3299 | // ==> nop; nop |
| 3300 | gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL); |
| 3301 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2); |
| 3302 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3303 | view[0] == 0xff && view[1] == 0x10); |
| 3304 | view[0] = 0x66; |
| 3305 | view[1] = 0x90; |
| 3306 | } |
| 3307 | } |
| 3308 | |
| 3309 | // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL |
| 3310 | // General-Dynamic to an Initial-Exec. |
| 3311 | |
| 3312 | inline void |
| 3313 | Target_i386::Relocate::tls_desc_gd_to_ie( |
| 3314 | const Relocate_info<32, false>* relinfo, |
| 3315 | size_t relnum, |
| 3316 | Output_segment*, |
| 3317 | const elfcpp::Rel<32, false>& rel, |
| 3318 | unsigned int r_type, |
| 3319 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 3320 | unsigned char* view, |
| 3321 | section_size_type view_size) |
| 3322 | { |
| 3323 | if (r_type == elfcpp::R_386_TLS_GOTDESC) |
| 3324 | { |
| 3325 | // leal foo@TLSDESC(%ebx), %eax |
| 3326 | // ==> movl foo@GOTNTPOFF(%ebx), %eax |
| 3327 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3328 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 3329 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3330 | view[-2] == 0x8d && view[-1] == 0x83); |
| 3331 | view[-2] = 0x8b; |
| 3332 | Relocate_functions<32, false>::rel32(view, value); |
| 3333 | } |
| 3334 | else |
| 3335 | { |
| 3336 | // call *foo@TLSCALL(%eax) |
| 3337 | // ==> nop; nop |
| 3338 | gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL); |
| 3339 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2); |
| 3340 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3341 | view[0] == 0xff && view[1] == 0x10); |
| 3342 | view[0] = 0x66; |
| 3343 | view[1] = 0x90; |
| 3344 | } |
| 3345 | } |
| 3346 | |
| 3347 | // Do a relocation in which we convert a TLS Local-Dynamic to a |
| 3348 | // Local-Exec. |
| 3349 | |
| 3350 | inline void |
| 3351 | Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo, |
| 3352 | size_t relnum, |
| 3353 | Output_segment*, |
| 3354 | const elfcpp::Rel<32, false>& rel, |
| 3355 | unsigned int, |
| 3356 | elfcpp::Elf_types<32>::Elf_Addr, |
| 3357 | unsigned char* view, |
| 3358 | section_size_type view_size) |
| 3359 | { |
| 3360 | // leal foo(%reg), %eax; call ___tls_get_addr |
| 3361 | // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi |
| 3362 | |
| 3363 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3364 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9); |
| 3365 | |
| 3366 | // FIXME: Does this test really always pass? |
| 3367 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3368 | view[-2] == 0x8d && view[-1] == 0x83); |
| 3369 | |
| 3370 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8); |
| 3371 | |
| 3372 | memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11); |
| 3373 | |
| 3374 | // The next reloc should be a PLT32 reloc against __tls_get_addr. |
| 3375 | // We can skip it. |
| 3376 | this->skip_call_tls_get_addr_ = true; |
| 3377 | } |
| 3378 | |
| 3379 | // Do a relocation in which we convert a TLS Initial-Exec to a |
| 3380 | // Local-Exec. |
| 3381 | |
| 3382 | inline void |
| 3383 | Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo, |
| 3384 | size_t relnum, |
| 3385 | Output_segment* tls_segment, |
| 3386 | const elfcpp::Rel<32, false>& rel, |
| 3387 | unsigned int r_type, |
| 3388 | elfcpp::Elf_types<32>::Elf_Addr value, |
| 3389 | unsigned char* view, |
| 3390 | section_size_type view_size) |
| 3391 | { |
| 3392 | // We have to actually change the instructions, which means that we |
| 3393 | // need to examine the opcodes to figure out which instruction we |
| 3394 | // are looking at. |
| 3395 | if (r_type == elfcpp::R_386_TLS_IE) |
| 3396 | { |
| 3397 | // movl %gs:XX,%eax ==> movl $YY,%eax |
| 3398 | // movl %gs:XX,%reg ==> movl $YY,%reg |
| 3399 | // addl %gs:XX,%reg ==> addl $YY,%reg |
| 3400 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1); |
| 3401 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 3402 | |
| 3403 | unsigned char op1 = view[-1]; |
| 3404 | if (op1 == 0xa1) |
| 3405 | { |
| 3406 | // movl XX,%eax ==> movl $YY,%eax |
| 3407 | view[-1] = 0xb8; |
| 3408 | } |
| 3409 | else |
| 3410 | { |
| 3411 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3412 | |
| 3413 | unsigned char op2 = view[-2]; |
| 3414 | if (op2 == 0x8b) |
| 3415 | { |
| 3416 | // movl XX,%reg ==> movl $YY,%reg |
| 3417 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3418 | (op1 & 0xc7) == 0x05); |
| 3419 | view[-2] = 0xc7; |
| 3420 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 3421 | } |
| 3422 | else if (op2 == 0x03) |
| 3423 | { |
| 3424 | // addl XX,%reg ==> addl $YY,%reg |
| 3425 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3426 | (op1 & 0xc7) == 0x05); |
| 3427 | view[-2] = 0x81; |
| 3428 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 3429 | } |
| 3430 | else |
| 3431 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0); |
| 3432 | } |
| 3433 | } |
| 3434 | else |
| 3435 | { |
| 3436 | // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| 3437 | // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| 3438 | // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| 3439 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2); |
| 3440 | tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4); |
| 3441 | |
| 3442 | unsigned char op1 = view[-1]; |
| 3443 | unsigned char op2 = view[-2]; |
| 3444 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), |
| 3445 | (op1 & 0xc0) == 0x80 && (op1 & 7) != 4); |
| 3446 | if (op2 == 0x8b) |
| 3447 | { |
| 3448 | // movl %gs:XX(%reg1),%reg2 ==> movl $YY,%reg2 |
| 3449 | view[-2] = 0xc7; |
| 3450 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 3451 | } |
| 3452 | else if (op2 == 0x2b) |
| 3453 | { |
| 3454 | // subl %gs:XX(%reg1),%reg2 ==> subl $YY,%reg2 |
| 3455 | view[-2] = 0x81; |
| 3456 | view[-1] = 0xe8 | ((op1 >> 3) & 7); |
| 3457 | } |
| 3458 | else if (op2 == 0x03) |
| 3459 | { |
| 3460 | // addl %gs:XX(%reg1),%reg2 ==> addl $YY,$reg2 |
| 3461 | view[-2] = 0x81; |
| 3462 | view[-1] = 0xc0 | ((op1 >> 3) & 7); |
| 3463 | } |
| 3464 | else |
| 3465 | tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0); |
| 3466 | } |
| 3467 | |
| 3468 | value = tls_segment->memsz() - value; |
| 3469 | if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE) |
| 3470 | value = - value; |
| 3471 | |
| 3472 | Relocate_functions<32, false>::rel32(view, value); |
| 3473 | } |
| 3474 | |
| 3475 | // Relocate section data. |
| 3476 | |
| 3477 | void |
| 3478 | Target_i386::relocate_section(const Relocate_info<32, false>* relinfo, |
| 3479 | unsigned int sh_type, |
| 3480 | const unsigned char* prelocs, |
| 3481 | size_t reloc_count, |
| 3482 | Output_section* output_section, |
| 3483 | bool needs_special_offset_handling, |
| 3484 | unsigned char* view, |
| 3485 | elfcpp::Elf_types<32>::Elf_Addr address, |
| 3486 | section_size_type view_size, |
| 3487 | const Reloc_symbol_changes* reloc_symbol_changes) |
| 3488 | { |
| 3489 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 3490 | |
| 3491 | gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL, |
| 3492 | Target_i386::Relocate, gold::Default_comdat_behavior>( |
| 3493 | relinfo, |
| 3494 | this, |
| 3495 | prelocs, |
| 3496 | reloc_count, |
| 3497 | output_section, |
| 3498 | needs_special_offset_handling, |
| 3499 | view, |
| 3500 | address, |
| 3501 | view_size, |
| 3502 | reloc_symbol_changes); |
| 3503 | } |
| 3504 | |
| 3505 | // Return the size of a relocation while scanning during a relocatable |
| 3506 | // link. |
| 3507 | |
| 3508 | unsigned int |
| 3509 | Target_i386::Relocatable_size_for_reloc::get_size_for_reloc( |
| 3510 | unsigned int r_type, |
| 3511 | Relobj* object) |
| 3512 | { |
| 3513 | switch (r_type) |
| 3514 | { |
| 3515 | case elfcpp::R_386_NONE: |
| 3516 | case elfcpp::R_386_GNU_VTINHERIT: |
| 3517 | case elfcpp::R_386_GNU_VTENTRY: |
| 3518 | case elfcpp::R_386_TLS_GD: // Global-dynamic |
| 3519 | case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url) |
| 3520 | case elfcpp::R_386_TLS_DESC_CALL: |
| 3521 | case elfcpp::R_386_TLS_LDM: // Local-dynamic |
| 3522 | case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic |
| 3523 | case elfcpp::R_386_TLS_IE: // Initial-exec |
| 3524 | case elfcpp::R_386_TLS_IE_32: |
| 3525 | case elfcpp::R_386_TLS_GOTIE: |
| 3526 | case elfcpp::R_386_TLS_LE: // Local-exec |
| 3527 | case elfcpp::R_386_TLS_LE_32: |
| 3528 | return 0; |
| 3529 | |
| 3530 | case elfcpp::R_386_32: |
| 3531 | case elfcpp::R_386_PC32: |
| 3532 | case elfcpp::R_386_GOT32: |
| 3533 | case elfcpp::R_386_PLT32: |
| 3534 | case elfcpp::R_386_GOTOFF: |
| 3535 | case elfcpp::R_386_GOTPC: |
| 3536 | return 4; |
| 3537 | |
| 3538 | case elfcpp::R_386_16: |
| 3539 | case elfcpp::R_386_PC16: |
| 3540 | return 2; |
| 3541 | |
| 3542 | case elfcpp::R_386_8: |
| 3543 | case elfcpp::R_386_PC8: |
| 3544 | return 1; |
| 3545 | |
| 3546 | // These are relocations which should only be seen by the |
| 3547 | // dynamic linker, and should never be seen here. |
| 3548 | case elfcpp::R_386_COPY: |
| 3549 | case elfcpp::R_386_GLOB_DAT: |
| 3550 | case elfcpp::R_386_JUMP_SLOT: |
| 3551 | case elfcpp::R_386_RELATIVE: |
| 3552 | case elfcpp::R_386_IRELATIVE: |
| 3553 | case elfcpp::R_386_TLS_TPOFF: |
| 3554 | case elfcpp::R_386_TLS_DTPMOD32: |
| 3555 | case elfcpp::R_386_TLS_DTPOFF32: |
| 3556 | case elfcpp::R_386_TLS_TPOFF32: |
| 3557 | case elfcpp::R_386_TLS_DESC: |
| 3558 | object->error(_("unexpected reloc %u in object file"), r_type); |
| 3559 | return 0; |
| 3560 | |
| 3561 | case elfcpp::R_386_32PLT: |
| 3562 | case elfcpp::R_386_TLS_GD_32: |
| 3563 | case elfcpp::R_386_TLS_GD_PUSH: |
| 3564 | case elfcpp::R_386_TLS_GD_CALL: |
| 3565 | case elfcpp::R_386_TLS_GD_POP: |
| 3566 | case elfcpp::R_386_TLS_LDM_32: |
| 3567 | case elfcpp::R_386_TLS_LDM_PUSH: |
| 3568 | case elfcpp::R_386_TLS_LDM_CALL: |
| 3569 | case elfcpp::R_386_TLS_LDM_POP: |
| 3570 | case elfcpp::R_386_USED_BY_INTEL_200: |
| 3571 | default: |
| 3572 | object->error(_("unsupported reloc %u in object file"), r_type); |
| 3573 | return 0; |
| 3574 | } |
| 3575 | } |
| 3576 | |
| 3577 | // Scan the relocs during a relocatable link. |
| 3578 | |
| 3579 | void |
| 3580 | Target_i386::scan_relocatable_relocs(Symbol_table* symtab, |
| 3581 | Layout* layout, |
| 3582 | Sized_relobj_file<32, false>* object, |
| 3583 | unsigned int data_shndx, |
| 3584 | unsigned int sh_type, |
| 3585 | const unsigned char* prelocs, |
| 3586 | size_t reloc_count, |
| 3587 | Output_section* output_section, |
| 3588 | bool needs_special_offset_handling, |
| 3589 | size_t local_symbol_count, |
| 3590 | const unsigned char* plocal_symbols, |
| 3591 | Relocatable_relocs* rr) |
| 3592 | { |
| 3593 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 3594 | |
| 3595 | typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL, |
| 3596 | Relocatable_size_for_reloc> Scan_relocatable_relocs; |
| 3597 | |
| 3598 | gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL, |
| 3599 | Scan_relocatable_relocs>( |
| 3600 | symtab, |
| 3601 | layout, |
| 3602 | object, |
| 3603 | data_shndx, |
| 3604 | prelocs, |
| 3605 | reloc_count, |
| 3606 | output_section, |
| 3607 | needs_special_offset_handling, |
| 3608 | local_symbol_count, |
| 3609 | plocal_symbols, |
| 3610 | rr); |
| 3611 | } |
| 3612 | |
| 3613 | // Emit relocations for a section. |
| 3614 | |
| 3615 | void |
| 3616 | Target_i386::relocate_relocs( |
| 3617 | const Relocate_info<32, false>* relinfo, |
| 3618 | unsigned int sh_type, |
| 3619 | const unsigned char* prelocs, |
| 3620 | size_t reloc_count, |
| 3621 | Output_section* output_section, |
| 3622 | elfcpp::Elf_types<32>::Elf_Off offset_in_output_section, |
| 3623 | const Relocatable_relocs* rr, |
| 3624 | unsigned char* view, |
| 3625 | elfcpp::Elf_types<32>::Elf_Addr view_address, |
| 3626 | section_size_type view_size, |
| 3627 | unsigned char* reloc_view, |
| 3628 | section_size_type reloc_view_size) |
| 3629 | { |
| 3630 | gold_assert(sh_type == elfcpp::SHT_REL); |
| 3631 | |
| 3632 | gold::relocate_relocs<32, false, elfcpp::SHT_REL>( |
| 3633 | relinfo, |
| 3634 | prelocs, |
| 3635 | reloc_count, |
| 3636 | output_section, |
| 3637 | offset_in_output_section, |
| 3638 | rr, |
| 3639 | view, |
| 3640 | view_address, |
| 3641 | view_size, |
| 3642 | reloc_view, |
| 3643 | reloc_view_size); |
| 3644 | } |
| 3645 | |
| 3646 | // Return the value to use for a dynamic which requires special |
| 3647 | // treatment. This is how we support equality comparisons of function |
| 3648 | // pointers across shared library boundaries, as described in the |
| 3649 | // processor specific ABI supplement. |
| 3650 | |
| 3651 | uint64_t |
| 3652 | Target_i386::do_dynsym_value(const Symbol* gsym) const |
| 3653 | { |
| 3654 | gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset()); |
| 3655 | return this->plt_address_for_global(gsym); |
| 3656 | } |
| 3657 | |
| 3658 | // Return a string used to fill a code section with nops to take up |
| 3659 | // the specified length. |
| 3660 | |
| 3661 | std::string |
| 3662 | Target_i386::do_code_fill(section_size_type length) const |
| 3663 | { |
| 3664 | if (length >= 16) |
| 3665 | { |
| 3666 | // Build a jmp instruction to skip over the bytes. |
| 3667 | unsigned char jmp[5]; |
| 3668 | jmp[0] = 0xe9; |
| 3669 | elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5); |
| 3670 | return (std::string(reinterpret_cast<char*>(&jmp[0]), 5) |
| 3671 | + std::string(length - 5, static_cast<char>(0x90))); |
| 3672 | } |
| 3673 | |
| 3674 | // Nop sequences of various lengths. |
| 3675 | const char nop1[1] = { '\x90' }; // nop |
| 3676 | const char nop2[2] = { '\x66', '\x90' }; // xchg %ax %ax |
| 3677 | const char nop3[3] = { '\x8d', '\x76', '\x00' }; // leal 0(%esi),%esi |
| 3678 | const char nop4[4] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi |
| 3679 | '\x00'}; |
| 3680 | const char nop5[5] = { '\x90', '\x8d', '\x74', // nop |
| 3681 | '\x26', '\x00' }; // leal 0(%esi,1),%esi |
| 3682 | const char nop6[6] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi |
| 3683 | '\x00', '\x00', '\x00' }; |
| 3684 | const char nop7[7] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi |
| 3685 | '\x00', '\x00', '\x00', |
| 3686 | '\x00' }; |
| 3687 | const char nop8[8] = { '\x90', '\x8d', '\xb4', // nop |
| 3688 | '\x26', '\x00', '\x00', // leal 0L(%esi,1),%esi |
| 3689 | '\x00', '\x00' }; |
| 3690 | const char nop9[9] = { '\x89', '\xf6', '\x8d', // movl %esi,%esi |
| 3691 | '\xbc', '\x27', '\x00', // leal 0L(%edi,1),%edi |
| 3692 | '\x00', '\x00', '\x00' }; |
| 3693 | const char nop10[10] = { '\x8d', '\x76', '\x00', // leal 0(%esi),%esi |
| 3694 | '\x8d', '\xbc', '\x27', // leal 0L(%edi,1),%edi |
| 3695 | '\x00', '\x00', '\x00', |
| 3696 | '\x00' }; |
| 3697 | const char nop11[11] = { '\x8d', '\x74', '\x26', // leal 0(%esi,1),%esi |
| 3698 | '\x00', '\x8d', '\xbc', // leal 0L(%edi,1),%edi |
| 3699 | '\x27', '\x00', '\x00', |
| 3700 | '\x00', '\x00' }; |
| 3701 | const char nop12[12] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi |
| 3702 | '\x00', '\x00', '\x00', // leal 0L(%edi),%edi |
| 3703 | '\x8d', '\xbf', '\x00', |
| 3704 | '\x00', '\x00', '\x00' }; |
| 3705 | const char nop13[13] = { '\x8d', '\xb6', '\x00', // leal 0L(%esi),%esi |
| 3706 | '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi |
| 3707 | '\x8d', '\xbc', '\x27', |
| 3708 | '\x00', '\x00', '\x00', |
| 3709 | '\x00' }; |
| 3710 | const char nop14[14] = { '\x8d', '\xb4', '\x26', // leal 0L(%esi,1),%esi |
| 3711 | '\x00', '\x00', '\x00', // leal 0L(%edi,1),%edi |
| 3712 | '\x00', '\x8d', '\xbc', |
| 3713 | '\x27', '\x00', '\x00', |
| 3714 | '\x00', '\x00' }; |
| 3715 | const char nop15[15] = { '\xeb', '\x0d', '\x90', // jmp .+15 |
| 3716 | '\x90', '\x90', '\x90', // nop,nop,nop,... |
| 3717 | '\x90', '\x90', '\x90', |
| 3718 | '\x90', '\x90', '\x90', |
| 3719 | '\x90', '\x90', '\x90' }; |
| 3720 | |
| 3721 | const char* nops[16] = { |
| 3722 | NULL, |
| 3723 | nop1, nop2, nop3, nop4, nop5, nop6, nop7, |
| 3724 | nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15 |
| 3725 | }; |
| 3726 | |
| 3727 | return std::string(nops[length], length); |
| 3728 | } |
| 3729 | |
| 3730 | // Return the value to use for the base of a DW_EH_PE_datarel offset |
| 3731 | // in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their |
| 3732 | // assembler can not write out the difference between two labels in |
| 3733 | // different sections, so instead of using a pc-relative value they |
| 3734 | // use an offset from the GOT. |
| 3735 | |
| 3736 | uint64_t |
| 3737 | Target_i386::do_ehframe_datarel_base() const |
| 3738 | { |
| 3739 | gold_assert(this->global_offset_table_ != NULL); |
| 3740 | Symbol* sym = this->global_offset_table_; |
| 3741 | Sized_symbol<32>* ssym = static_cast<Sized_symbol<32>*>(sym); |
| 3742 | return ssym->value(); |
| 3743 | } |
| 3744 | |
| 3745 | // Return whether SYM should be treated as a call to a non-split |
| 3746 | // function. We don't want that to be true of a call to a |
| 3747 | // get_pc_thunk function. |
| 3748 | |
| 3749 | bool |
| 3750 | Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const |
| 3751 | { |
| 3752 | return (sym->type() == elfcpp::STT_FUNC |
| 3753 | && !is_prefix_of("__i686.get_pc_thunk.", sym->name())); |
| 3754 | } |
| 3755 | |
| 3756 | // FNOFFSET in section SHNDX in OBJECT is the start of a function |
| 3757 | // compiled with -fsplit-stack. The function calls non-split-stack |
| 3758 | // code. We have to change the function so that it always ensures |
| 3759 | // that it has enough stack space to run some random function. |
| 3760 | |
| 3761 | void |
| 3762 | Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx, |
| 3763 | section_offset_type fnoffset, |
| 3764 | section_size_type fnsize, |
| 3765 | unsigned char* view, |
| 3766 | section_size_type view_size, |
| 3767 | std::string* from, |
| 3768 | std::string* to) const |
| 3769 | { |
| 3770 | // The function starts with a comparison of the stack pointer and a |
| 3771 | // field in the TCB. This is followed by a jump. |
| 3772 | |
| 3773 | // cmp %gs:NN,%esp |
| 3774 | if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3) |
| 3775 | && fnsize > 7) |
| 3776 | { |
| 3777 | // We will call __morestack if the carry flag is set after this |
| 3778 | // comparison. We turn the comparison into an stc instruction |
| 3779 | // and some nops. |
| 3780 | view[fnoffset] = '\xf9'; |
| 3781 | this->set_view_to_nop(view, view_size, fnoffset + 1, 6); |
| 3782 | } |
| 3783 | // lea NN(%esp),%ecx |
| 3784 | // lea NN(%esp),%edx |
| 3785 | else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3) |
| 3786 | || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3)) |
| 3787 | && fnsize > 7) |
| 3788 | { |
| 3789 | // This is loading an offset from the stack pointer for a |
| 3790 | // comparison. The offset is negative, so we decrease the |
| 3791 | // offset by the amount of space we need for the stack. This |
| 3792 | // means we will avoid calling __morestack if there happens to |
| 3793 | // be plenty of space on the stack already. |
| 3794 | unsigned char* pval = view + fnoffset + 3; |
| 3795 | uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval); |
| 3796 | val -= parameters->options().split_stack_adjust_size(); |
| 3797 | elfcpp::Swap_unaligned<32, false>::writeval(pval, val); |
| 3798 | } |
| 3799 | else |
| 3800 | { |
| 3801 | if (!object->has_no_split_stack()) |
| 3802 | object->error(_("failed to match split-stack sequence at " |
| 3803 | "section %u offset %0zx"), |
| 3804 | shndx, static_cast<size_t>(fnoffset)); |
| 3805 | return; |
| 3806 | } |
| 3807 | |
| 3808 | // We have to change the function so that it calls |
| 3809 | // __morestack_non_split instead of __morestack. The former will |
| 3810 | // allocate additional stack space. |
| 3811 | *from = "__morestack"; |
| 3812 | *to = "__morestack_non_split"; |
| 3813 | } |
| 3814 | |
| 3815 | // The selector for i386 object files. Note this is never instantiated |
| 3816 | // directly. It's only used in Target_selector_i386_nacl, below. |
| 3817 | |
| 3818 | class Target_selector_i386 : public Target_selector_freebsd |
| 3819 | { |
| 3820 | public: |
| 3821 | Target_selector_i386() |
| 3822 | : Target_selector_freebsd(elfcpp::EM_386, 32, false, |
| 3823 | "elf32-i386", "elf32-i386-freebsd", |
| 3824 | "elf_i386") |
| 3825 | { } |
| 3826 | |
| 3827 | Target* |
| 3828 | do_instantiate_target() |
| 3829 | { return new Target_i386(); } |
| 3830 | }; |
| 3831 | |
| 3832 | // NaCl variant. It uses different PLT contents. |
| 3833 | |
| 3834 | class Output_data_plt_i386_nacl : public Output_data_plt_i386 |
| 3835 | { |
| 3836 | public: |
| 3837 | Output_data_plt_i386_nacl(Layout* layout, |
| 3838 | Output_data_space* got_plt, |
| 3839 | Output_data_space* got_irelative) |
| 3840 | : Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative) |
| 3841 | { } |
| 3842 | |
| 3843 | protected: |
| 3844 | virtual unsigned int |
| 3845 | do_get_plt_entry_size() const |
| 3846 | { return plt_entry_size; } |
| 3847 | |
| 3848 | virtual void |
| 3849 | do_add_eh_frame(Layout* layout) |
| 3850 | { |
| 3851 | layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size, |
| 3852 | plt_eh_frame_fde, plt_eh_frame_fde_size); |
| 3853 | } |
| 3854 | |
| 3855 | // The size of an entry in the PLT. |
| 3856 | static const int plt_entry_size = 64; |
| 3857 | |
| 3858 | // The .eh_frame unwind information for the PLT. |
| 3859 | static const int plt_eh_frame_fde_size = 32; |
| 3860 | static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size]; |
| 3861 | }; |
| 3862 | |
| 3863 | class Output_data_plt_i386_nacl_exec : public Output_data_plt_i386_nacl |
| 3864 | { |
| 3865 | public: |
| 3866 | Output_data_plt_i386_nacl_exec(Layout* layout, |
| 3867 | Output_data_space* got_plt, |
| 3868 | Output_data_space* got_irelative) |
| 3869 | : Output_data_plt_i386_nacl(layout, got_plt, got_irelative) |
| 3870 | { } |
| 3871 | |
| 3872 | protected: |
| 3873 | virtual void |
| 3874 | do_fill_first_plt_entry(unsigned char* pov, |
| 3875 | elfcpp::Elf_types<32>::Elf_Addr got_address); |
| 3876 | |
| 3877 | virtual unsigned int |
| 3878 | do_fill_plt_entry(unsigned char* pov, |
| 3879 | elfcpp::Elf_types<32>::Elf_Addr got_address, |
| 3880 | unsigned int got_offset, |
| 3881 | unsigned int plt_offset, |
| 3882 | unsigned int plt_rel_offset); |
| 3883 | |
| 3884 | private: |
| 3885 | // The first entry in the PLT for an executable. |
| 3886 | static const unsigned char first_plt_entry[plt_entry_size]; |
| 3887 | |
| 3888 | // Other entries in the PLT for an executable. |
| 3889 | static const unsigned char plt_entry[plt_entry_size]; |
| 3890 | }; |
| 3891 | |
| 3892 | class Output_data_plt_i386_nacl_dyn : public Output_data_plt_i386_nacl |
| 3893 | { |
| 3894 | public: |
| 3895 | Output_data_plt_i386_nacl_dyn(Layout* layout, |
| 3896 | Output_data_space* got_plt, |
| 3897 | Output_data_space* got_irelative) |
| 3898 | : Output_data_plt_i386_nacl(layout, got_plt, got_irelative) |
| 3899 | { } |
| 3900 | |
| 3901 | protected: |
| 3902 | virtual void |
| 3903 | do_fill_first_plt_entry(unsigned char* pov, elfcpp::Elf_types<32>::Elf_Addr); |
| 3904 | |
| 3905 | virtual unsigned int |
| 3906 | do_fill_plt_entry(unsigned char* pov, |
| 3907 | elfcpp::Elf_types<32>::Elf_Addr, |
| 3908 | unsigned int got_offset, |
| 3909 | unsigned int plt_offset, |
| 3910 | unsigned int plt_rel_offset); |
| 3911 | |
| 3912 | private: |
| 3913 | // The first entry in the PLT for a shared object. |
| 3914 | static const unsigned char first_plt_entry[plt_entry_size]; |
| 3915 | |
| 3916 | // Other entries in the PLT for a shared object. |
| 3917 | static const unsigned char plt_entry[plt_entry_size]; |
| 3918 | }; |
| 3919 | |
| 3920 | class Target_i386_nacl : public Target_i386 |
| 3921 | { |
| 3922 | public: |
| 3923 | Target_i386_nacl() |
| 3924 | : Target_i386(&i386_nacl_info) |
| 3925 | { } |
| 3926 | |
| 3927 | protected: |
| 3928 | virtual Output_data_plt_i386* |
| 3929 | do_make_data_plt(Layout* layout, |
| 3930 | Output_data_space* got_plt, |
| 3931 | Output_data_space* got_irelative, |
| 3932 | bool dyn) |
| 3933 | { |
| 3934 | if (dyn) |
| 3935 | return new Output_data_plt_i386_nacl_dyn(layout, got_plt, got_irelative); |
| 3936 | else |
| 3937 | return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative); |
| 3938 | } |
| 3939 | |
| 3940 | virtual std::string |
| 3941 | do_code_fill(section_size_type length) const; |
| 3942 | |
| 3943 | private: |
| 3944 | static const Target::Target_info i386_nacl_info; |
| 3945 | }; |
| 3946 | |
| 3947 | const Target::Target_info Target_i386_nacl::i386_nacl_info = |
| 3948 | { |
| 3949 | 32, // size |
| 3950 | false, // is_big_endian |
| 3951 | elfcpp::EM_386, // machine_code |
| 3952 | false, // has_make_symbol |
| 3953 | false, // has_resolve |
| 3954 | true, // has_code_fill |
| 3955 | true, // is_default_stack_executable |
| 3956 | true, // can_icf_inline_merge_sections |
| 3957 | '\0', // wrap_char |
| 3958 | "/lib/ld-nacl-x86-32.so.1", // dynamic_linker |
| 3959 | 0x20000, // default_text_segment_address |
| 3960 | 0x10000, // abi_pagesize (overridable by -z max-page-size) |
| 3961 | 0x10000, // common_pagesize (overridable by -z common-page-size) |
| 3962 | true, // isolate_execinstr |
| 3963 | 0x10000000, // rosegment_gap |
| 3964 | elfcpp::SHN_UNDEF, // small_common_shndx |
| 3965 | elfcpp::SHN_UNDEF, // large_common_shndx |
| 3966 | 0, // small_common_section_flags |
| 3967 | 0, // large_common_section_flags |
| 3968 | NULL, // attributes_section |
| 3969 | NULL, // attributes_vendor |
| 3970 | "_start" // entry_symbol_name |
| 3971 | }; |
| 3972 | |
| 3973 | #define NACLMASK 0xe0 // 32-byte alignment mask |
| 3974 | |
| 3975 | const unsigned char |
| 3976 | Output_data_plt_i386_nacl_exec::first_plt_entry[plt_entry_size] = |
| 3977 | { |
| 3978 | 0xff, 0x35, // pushl contents of memory address |
| 3979 | 0, 0, 0, 0, // replaced with address of .got + 4 |
| 3980 | 0x8b, 0x0d, // movl contents of address, %ecx |
| 3981 | 0, 0, 0, 0, // replaced with address of .got + 8 |
| 3982 | 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx |
| 3983 | 0xff, 0xe1, // jmp *%ecx |
| 3984 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3985 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3986 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3987 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3988 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3989 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3990 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 3991 | 0x90, 0x90, 0x90, 0x90, 0x90 |
| 3992 | }; |
| 3993 | |
| 3994 | void |
| 3995 | Output_data_plt_i386_nacl_exec::do_fill_first_plt_entry( |
| 3996 | unsigned char* pov, |
| 3997 | elfcpp::Elf_types<32>::Elf_Addr got_address) |
| 3998 | { |
| 3999 | memcpy(pov, first_plt_entry, plt_entry_size); |
| 4000 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4); |
| 4001 | elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8); |
| 4002 | } |
| 4003 | |
| 4004 | // The first entry in the PLT for a shared object. |
| 4005 | |
| 4006 | const unsigned char |
| 4007 | Output_data_plt_i386_nacl_dyn::first_plt_entry[plt_entry_size] = |
| 4008 | { |
| 4009 | 0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx) |
| 4010 | 0x8b, 0x4b, 0x08, // mov 0x8(%ebx), %ecx |
| 4011 | 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx |
| 4012 | 0xff, 0xe1, // jmp *%ecx |
| 4013 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4014 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4015 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4016 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4017 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4018 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4019 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4020 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4021 | 0x90, 0x90, 0x90, 0x90, 0x90, // nops |
| 4022 | 0x90, 0x90, 0x90, 0x90, 0x90 // nops |
| 4023 | }; |
| 4024 | |
| 4025 | void |
| 4026 | Output_data_plt_i386_nacl_dyn::do_fill_first_plt_entry( |
| 4027 | unsigned char* pov, |
| 4028 | elfcpp::Elf_types<32>::Elf_Addr) |
| 4029 | { |
| 4030 | memcpy(pov, first_plt_entry, plt_entry_size); |
| 4031 | } |
| 4032 | |
| 4033 | // Subsequent entries in the PLT for an executable. |
| 4034 | |
| 4035 | const unsigned char |
| 4036 | Output_data_plt_i386_nacl_exec::plt_entry[plt_entry_size] = |
| 4037 | { |
| 4038 | 0x8b, 0x0d, // movl contents of address, %ecx */ |
| 4039 | 0, 0, 0, 0, // replaced with address of symbol in .got |
| 4040 | 0x83, 0xe1, NACLMASK, // andl $NACLMASK, %ecx |
| 4041 | 0xff, 0xe1, // jmp *%ecx |
| 4042 | |
| 4043 | // Pad to the next 32-byte boundary with nop instructions. |
| 4044 | 0x90, |
| 4045 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4046 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4047 | |
| 4048 | // Lazy GOT entries point here (32-byte aligned). |
| 4049 | 0x68, // pushl immediate |
| 4050 | 0, 0, 0, 0, // replaced with offset into relocation table |
| 4051 | 0xe9, // jmp relative |
| 4052 | 0, 0, 0, 0, // replaced with offset to start of .plt |
| 4053 | |
| 4054 | // Pad to the next 32-byte boundary with nop instructions. |
| 4055 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4056 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4057 | 0x90, 0x90 |
| 4058 | }; |
| 4059 | |
| 4060 | unsigned int |
| 4061 | Output_data_plt_i386_nacl_exec::do_fill_plt_entry( |
| 4062 | unsigned char* pov, |
| 4063 | elfcpp::Elf_types<32>::Elf_Addr got_address, |
| 4064 | unsigned int got_offset, |
| 4065 | unsigned int plt_offset, |
| 4066 | unsigned int plt_rel_offset) |
| 4067 | { |
| 4068 | memcpy(pov, plt_entry, plt_entry_size); |
| 4069 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, |
| 4070 | got_address + got_offset); |
| 4071 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset); |
| 4072 | elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4)); |
| 4073 | return 32; |
| 4074 | } |
| 4075 | |
| 4076 | // Subsequent entries in the PLT for a shared object. |
| 4077 | |
| 4078 | const unsigned char |
| 4079 | Output_data_plt_i386_nacl_dyn::plt_entry[plt_entry_size] = |
| 4080 | { |
| 4081 | 0x8b, 0x8b, // movl offset(%ebx), %ecx |
| 4082 | 0, 0, 0, 0, // replaced with offset of symbol in .got |
| 4083 | 0x83, 0xe1, 0xe0, // andl $NACLMASK, %ecx |
| 4084 | 0xff, 0xe1, // jmp *%ecx |
| 4085 | |
| 4086 | // Pad to the next 32-byte boundary with nop instructions. |
| 4087 | 0x90, |
| 4088 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4089 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4090 | |
| 4091 | // Lazy GOT entries point here (32-byte aligned). |
| 4092 | 0x68, // pushl immediate |
| 4093 | 0, 0, 0, 0, // replaced with offset into relocation table. |
| 4094 | 0xe9, // jmp relative |
| 4095 | 0, 0, 0, 0, // replaced with offset to start of .plt. |
| 4096 | |
| 4097 | // Pad to the next 32-byte boundary with nop instructions. |
| 4098 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4099 | 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, |
| 4100 | 0x90, 0x90 |
| 4101 | }; |
| 4102 | |
| 4103 | unsigned int |
| 4104 | Output_data_plt_i386_nacl_dyn::do_fill_plt_entry( |
| 4105 | unsigned char* pov, |
| 4106 | elfcpp::Elf_types<32>::Elf_Addr, |
| 4107 | unsigned int got_offset, |
| 4108 | unsigned int plt_offset, |
| 4109 | unsigned int plt_rel_offset) |
| 4110 | { |
| 4111 | memcpy(pov, plt_entry, plt_entry_size); |
| 4112 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset); |
| 4113 | elfcpp::Swap_unaligned<32, false>::writeval(pov + 33, plt_rel_offset); |
| 4114 | elfcpp::Swap<32, false>::writeval(pov + 38, - (plt_offset + 38 + 4)); |
| 4115 | return 32; |
| 4116 | } |
| 4117 | |
| 4118 | const unsigned char |
| 4119 | Output_data_plt_i386_nacl::plt_eh_frame_fde[plt_eh_frame_fde_size] = |
| 4120 | { |
| 4121 | 0, 0, 0, 0, // Replaced with offset to .plt. |
| 4122 | 0, 0, 0, 0, // Replaced with size of .plt. |
| 4123 | 0, // Augmentation size. |
| 4124 | elfcpp::DW_CFA_def_cfa_offset, 8, // DW_CFA_def_cfa_offset: 8. |
| 4125 | elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6. |
| 4126 | elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12. |
| 4127 | elfcpp::DW_CFA_advance_loc + 58, // Advance 58 to __PLT__ + 64. |
| 4128 | elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression. |
| 4129 | 13, // Block length. |
| 4130 | elfcpp::DW_OP_breg4, 4, // Push %esp + 4. |
| 4131 | elfcpp::DW_OP_breg8, 0, // Push %eip. |
| 4132 | elfcpp::DW_OP_const1u, 63, // Push 0x3f. |
| 4133 | elfcpp::DW_OP_and, // & (%eip & 0x3f). |
| 4134 | elfcpp::DW_OP_const1u, 37, // Push 0x25. |
| 4135 | elfcpp::DW_OP_ge, // >= ((%eip & 0x3f) >= 0x25) |
| 4136 | elfcpp::DW_OP_lit2, // Push 2. |
| 4137 | elfcpp::DW_OP_shl, // << (((%eip & 0x3f) >= 0x25) << 2) |
| 4138 | elfcpp::DW_OP_plus, // + ((((%eip&0x3f)>=0x25)<<2)+%esp+4 |
| 4139 | elfcpp::DW_CFA_nop, // Align to 32 bytes. |
| 4140 | elfcpp::DW_CFA_nop |
| 4141 | }; |
| 4142 | |
| 4143 | // Return a string used to fill a code section with nops. |
| 4144 | // For NaCl, long NOPs are only valid if they do not cross |
| 4145 | // bundle alignment boundaries, so keep it simple with one-byte NOPs. |
| 4146 | std::string |
| 4147 | Target_i386_nacl::do_code_fill(section_size_type length) const |
| 4148 | { |
| 4149 | return std::string(length, static_cast<char>(0x90)); |
| 4150 | } |
| 4151 | |
| 4152 | // The selector for i386-nacl object files. |
| 4153 | |
| 4154 | class Target_selector_i386_nacl |
| 4155 | : public Target_selector_nacl<Target_selector_i386, Target_i386_nacl> |
| 4156 | { |
| 4157 | public: |
| 4158 | Target_selector_i386_nacl() |
| 4159 | : Target_selector_nacl<Target_selector_i386, |
| 4160 | Target_i386_nacl>("x86-32", |
| 4161 | "elf32-i386-nacl", |
| 4162 | "elf_i386_nacl") |
| 4163 | { } |
| 4164 | }; |
| 4165 | |
| 4166 | Target_selector_i386_nacl target_selector_i386; |
| 4167 | |
| 4168 | } // End anonymous namespace. |