| 1 | // output.h -- manage the output file for gold -*- C++ -*- |
| 2 | |
| 3 | #ifndef GOLD_OUTPUT_H |
| 4 | #define GOLD_OUTPUT_H |
| 5 | |
| 6 | #include <cassert> |
| 7 | #include <list> |
| 8 | |
| 9 | #include "elfcpp.h" |
| 10 | #include "layout.h" |
| 11 | |
| 12 | namespace gold |
| 13 | { |
| 14 | |
| 15 | class Object; |
| 16 | class Output_file; |
| 17 | |
| 18 | template<int size, bool big_endian> |
| 19 | class Sized_target; |
| 20 | |
| 21 | // An abtract class for data which has to go into the output file. |
| 22 | |
| 23 | class Output_data |
| 24 | { |
| 25 | public: |
| 26 | explicit Output_data(off_t data_size = 0) |
| 27 | : address_(0), data_size_(data_size), offset_(0) |
| 28 | { } |
| 29 | |
| 30 | virtual |
| 31 | ~Output_data(); |
| 32 | |
| 33 | // Return the address. |
| 34 | uint64_t |
| 35 | address() const |
| 36 | { return this->address_; } |
| 37 | |
| 38 | // Return the size of the data. |
| 39 | off_t |
| 40 | data_size() const |
| 41 | { return this->data_size_; } |
| 42 | |
| 43 | // Return the file offset. |
| 44 | off_t |
| 45 | offset() const |
| 46 | { return this->offset_; } |
| 47 | |
| 48 | // Return the required alignment. |
| 49 | uint64_t |
| 50 | addralign() const |
| 51 | { return this->do_addralign(); } |
| 52 | |
| 53 | // Return whether this is an Output_section. |
| 54 | bool |
| 55 | is_section() const |
| 56 | { return this->do_is_section(); } |
| 57 | |
| 58 | // Return whether this is an Output_section of the specified type. |
| 59 | bool |
| 60 | is_section_type(elfcpp::Elf_Word stt) const |
| 61 | { return this->do_is_section_type(stt); } |
| 62 | |
| 63 | // Return whether this is an Output_section with the specified flag |
| 64 | // set. |
| 65 | bool |
| 66 | is_section_flag_set(elfcpp::Elf_Xword shf) const |
| 67 | { return this->do_is_section_flag_set(shf); } |
| 68 | |
| 69 | // Set the address and file offset of this data. |
| 70 | void |
| 71 | set_address(uint64_t addr, off_t off); |
| 72 | |
| 73 | // Write the data to the output file. |
| 74 | void |
| 75 | write(Output_file* file) |
| 76 | { this->do_write(file); } |
| 77 | |
| 78 | protected: |
| 79 | // Functions that child classes may or in some cases must implement. |
| 80 | |
| 81 | // Write the data to the output file. |
| 82 | virtual void |
| 83 | do_write(Output_file*) = 0; |
| 84 | |
| 85 | // Return the required alignment. |
| 86 | virtual uint64_t |
| 87 | do_addralign() const = 0; |
| 88 | |
| 89 | // Return whether this is an Output_section. |
| 90 | virtual bool |
| 91 | do_is_section() const |
| 92 | { return false; } |
| 93 | |
| 94 | // Return whether this is an Output_section of the specified type. |
| 95 | // This only needs to be implement by Output_section. |
| 96 | virtual bool |
| 97 | do_is_section_type(elfcpp::Elf_Word) const |
| 98 | { return false; } |
| 99 | |
| 100 | // Return whether this is an Output_section with the specific flag |
| 101 | // set. This only needs to be implemented by Output_section. |
| 102 | virtual bool |
| 103 | do_is_section_flag_set(elfcpp::Elf_Xword) const |
| 104 | { return false; } |
| 105 | |
| 106 | // Set the address and file offset of the data. This only needs to |
| 107 | // be implemented if the child needs to know. |
| 108 | virtual void |
| 109 | do_set_address(uint64_t, off_t) |
| 110 | { } |
| 111 | |
| 112 | // Functions that child classes may call. |
| 113 | |
| 114 | // Set the size of the data. |
| 115 | void |
| 116 | set_data_size(off_t data_size) |
| 117 | { this->data_size_ = data_size; } |
| 118 | |
| 119 | // Return default alignment for a size--32 or 64. |
| 120 | static uint64_t |
| 121 | default_alignment(int size); |
| 122 | |
| 123 | private: |
| 124 | Output_data(const Output_data&); |
| 125 | Output_data& operator=(const Output_data&); |
| 126 | |
| 127 | // Memory address in file (not always meaningful). |
| 128 | uint64_t address_; |
| 129 | // Size of data in file. |
| 130 | off_t data_size_; |
| 131 | // Offset within file. |
| 132 | off_t offset_; |
| 133 | }; |
| 134 | |
| 135 | // A simple case of Output_data in which we have constant data to |
| 136 | // output. |
| 137 | |
| 138 | class Output_data_const : public Output_data |
| 139 | { |
| 140 | public: |
| 141 | Output_data_const(const std::string& data, uint64_t addralign) |
| 142 | : Output_data(data.size()), data_(data), addralign_(addralign) |
| 143 | { } |
| 144 | |
| 145 | Output_data_const(const char* p, off_t len, uint64_t addralign) |
| 146 | : Output_data(len), data_(p, len), addralign_(addralign) |
| 147 | { } |
| 148 | |
| 149 | // Write the data to the file. |
| 150 | void |
| 151 | do_write(Output_file* output); |
| 152 | |
| 153 | // Return the required alignment. |
| 154 | uint64_t |
| 155 | do_addralign() const |
| 156 | { return this->addralign_; } |
| 157 | |
| 158 | private: |
| 159 | std::string data_; |
| 160 | uint64_t addralign_; |
| 161 | }; |
| 162 | |
| 163 | // Output the section headers. |
| 164 | |
| 165 | class Output_section_headers : public Output_data |
| 166 | { |
| 167 | public: |
| 168 | Output_section_headers(int size, |
| 169 | const Layout::Segment_list&, |
| 170 | const Layout::Section_list&); |
| 171 | |
| 172 | // Write the data to the file. |
| 173 | void |
| 174 | do_write(Output_file*); |
| 175 | |
| 176 | // Return the required alignment. |
| 177 | uint64_t |
| 178 | do_addralign() const |
| 179 | { return Output_data::default_alignment(this->size_); } |
| 180 | |
| 181 | private: |
| 182 | int size_; |
| 183 | const Layout::Segment_list& segment_list_; |
| 184 | const Layout::Section_list& section_list_; |
| 185 | }; |
| 186 | |
| 187 | // Output the segment headers. |
| 188 | |
| 189 | class Output_segment_headers : public Output_data |
| 190 | { |
| 191 | public: |
| 192 | Output_segment_headers(int size, const Layout::Segment_list& segment_list) |
| 193 | : size_(size), segment_list_(segment_list) |
| 194 | { } |
| 195 | |
| 196 | // Write the data to the file. |
| 197 | void |
| 198 | do_write(Output_file*); |
| 199 | |
| 200 | // Return the required alignment. |
| 201 | uint64_t |
| 202 | do_addralign() const |
| 203 | { return Output_data::default_alignment(this->size_); } |
| 204 | |
| 205 | private: |
| 206 | int size_; |
| 207 | const Layout::Segment_list& segment_list_; |
| 208 | }; |
| 209 | |
| 210 | // Output the ELF file header. |
| 211 | |
| 212 | class Output_file_header : public Output_data |
| 213 | { |
| 214 | public: |
| 215 | Output_file_header(int size, |
| 216 | const General_options&, |
| 217 | const Target*, |
| 218 | const Symbol_table*, |
| 219 | const Output_segment_headers*); |
| 220 | |
| 221 | // Add information about the section headers. We lay out the ELF |
| 222 | // file header before we create the section headers. |
| 223 | void set_section_info(const Output_section_headers*, |
| 224 | const Output_section* shstrtab); |
| 225 | |
| 226 | // Write the data to the file. |
| 227 | void |
| 228 | do_write(Output_file*); |
| 229 | |
| 230 | // Return the required alignment. |
| 231 | uint64_t |
| 232 | do_addralign() const |
| 233 | { return Output_data::default_alignment(this->size_); } |
| 234 | |
| 235 | // Set the address and offset--we only implement this for error |
| 236 | // checking. |
| 237 | void |
| 238 | do_set_address(uint64_t, off_t off) const |
| 239 | { assert(off == 0); } |
| 240 | |
| 241 | private: |
| 242 | int size_; |
| 243 | const General_options& options_; |
| 244 | const Target* target_; |
| 245 | const Symbol_table* symtab_; |
| 246 | const Output_segment_headers* program_header_; |
| 247 | const Output_section_headers* section_header_; |
| 248 | const Output_section* shstrtab_; |
| 249 | }; |
| 250 | |
| 251 | // An output section. We don't expect to have too many output |
| 252 | // sections, so we don't bother to do a template on the size. |
| 253 | |
| 254 | class Output_section : public Output_data |
| 255 | { |
| 256 | public: |
| 257 | // Create an output section, giving the name, type, and flags. |
| 258 | Output_section(const char* name, elfcpp::Elf_Word, elfcpp::Elf_Xword); |
| 259 | virtual ~Output_section(); |
| 260 | |
| 261 | // Add a new input section named NAME with header SHDR from object |
| 262 | // OBJECT. Return the offset within the output section. |
| 263 | template<int size, bool big_endian> |
| 264 | off_t |
| 265 | add_input_section(Object* object, const char *name, |
| 266 | const elfcpp::Shdr<size, big_endian>& shdr); |
| 267 | |
| 268 | // Return the section name. |
| 269 | const char* |
| 270 | name() const |
| 271 | { return this->name_; } |
| 272 | |
| 273 | // Return the section type. |
| 274 | elfcpp::Elf_Word |
| 275 | type() const |
| 276 | { return this->type_; } |
| 277 | |
| 278 | // Return the section flags. |
| 279 | elfcpp::Elf_Xword |
| 280 | flags() const |
| 281 | { return this->flags_; } |
| 282 | |
| 283 | // Return the address alignment. |
| 284 | uint64_t |
| 285 | addralign() const |
| 286 | { return this->addralign_; } |
| 287 | |
| 288 | // Write the data to the file. For a typical Output_section, this |
| 289 | // does nothing. We write out the data by looping over all the |
| 290 | // input sections. |
| 291 | virtual void |
| 292 | do_write(Output_file*) |
| 293 | { } |
| 294 | |
| 295 | // Return the address alignment--function required by parent class. |
| 296 | uint64_t |
| 297 | do_addralign() const |
| 298 | { return this->addralign_; } |
| 299 | |
| 300 | // Return whether this is an Output_section. |
| 301 | bool |
| 302 | do_is_section() const |
| 303 | { return true; } |
| 304 | |
| 305 | // Return whether this is a section of the specified type. |
| 306 | bool |
| 307 | do_is_section_type(elfcpp::Elf_Word type) const |
| 308 | { return this->type_ == type; } |
| 309 | |
| 310 | // Return whether the specified section flag is set. |
| 311 | bool |
| 312 | do_is_section_flag_set(elfcpp::Elf_Xword flag) const |
| 313 | { return (this->flags_ & flag) != 0; } |
| 314 | |
| 315 | private: |
| 316 | // Most of these fields are only valid after layout. |
| 317 | |
| 318 | // The name of the section. This will point into a Stringpool. |
| 319 | const char* name_; |
| 320 | // The section address is in the parent class. |
| 321 | // The section alignment. |
| 322 | uint64_t addralign_; |
| 323 | // The section entry size. |
| 324 | uint64_t entsize_; |
| 325 | // The file offset is in the parent class. |
| 326 | // The section link field. |
| 327 | unsigned int link_; |
| 328 | // The section info field. |
| 329 | unsigned int info_; |
| 330 | // The section type. |
| 331 | elfcpp::Elf_Word type_; |
| 332 | // The section flags. |
| 333 | elfcpp::Elf_Xword flags_; |
| 334 | }; |
| 335 | |
| 336 | // A special Output_section which represents the symbol table |
| 337 | // (SHT_SYMTAB). |
| 338 | |
| 339 | class Output_section_symtab : public Output_section |
| 340 | { |
| 341 | public: |
| 342 | Output_section_symtab(const char* name, off_t size); |
| 343 | }; |
| 344 | |
| 345 | // A special Output_section which holds a string table. |
| 346 | |
| 347 | class Output_section_strtab : public Output_section |
| 348 | { |
| 349 | public: |
| 350 | Output_section_strtab(const char* name, Stringpool* contents); |
| 351 | |
| 352 | // Write out the data. |
| 353 | void |
| 354 | do_write(Output_file*); |
| 355 | |
| 356 | private: |
| 357 | Stringpool* contents_; |
| 358 | }; |
| 359 | |
| 360 | // An output segment. PT_LOAD segments are built from collections of |
| 361 | // output sections. Other segments typically point within PT_LOAD |
| 362 | // segments, and are built directly as needed. |
| 363 | |
| 364 | class Output_segment |
| 365 | { |
| 366 | public: |
| 367 | // Create an output segment, specifying the type and flags. |
| 368 | Output_segment(elfcpp::Elf_Word, elfcpp::Elf_Word); |
| 369 | |
| 370 | // Return the virtual address. |
| 371 | uint64_t |
| 372 | vaddr() const |
| 373 | { return this->vaddr_; } |
| 374 | |
| 375 | // Return the physical address. |
| 376 | uint64_t |
| 377 | paddr() const |
| 378 | { return this->paddr_; } |
| 379 | |
| 380 | // Return the segment type. |
| 381 | elfcpp::Elf_Word |
| 382 | type() const |
| 383 | { return this->type_; } |
| 384 | |
| 385 | // Return the segment flags. |
| 386 | elfcpp::Elf_Word |
| 387 | flags() const |
| 388 | { return this->flags_; } |
| 389 | |
| 390 | // Return the maximum alignment of the Output_data. |
| 391 | uint64_t |
| 392 | max_data_align() const; |
| 393 | |
| 394 | // Add an Output_section to this segment. |
| 395 | void |
| 396 | add_output_section(Output_section*, elfcpp::Elf_Word seg_flags); |
| 397 | |
| 398 | // Add an Output_data (which is not an Output_section) to the start |
| 399 | // of this segment. |
| 400 | void |
| 401 | add_initial_output_data(Output_data*); |
| 402 | |
| 403 | // Set the address of the segment to ADDR and the offset to *POFF |
| 404 | // (aligned if necessary), and set the addresses and offsets of all |
| 405 | // contained output sections accordingly. Return the address of the |
| 406 | // immediately following segment. Update *POFF. This should only |
| 407 | // be called for a PT_LOAD segment. |
| 408 | uint64_t |
| 409 | set_section_addresses(uint64_t addr, off_t* poff); |
| 410 | |
| 411 | // Set the offset of this segment based on the section. This should |
| 412 | // only be called for a non-PT_LOAD segment. |
| 413 | void |
| 414 | set_offset(); |
| 415 | |
| 416 | // Return the number of output sections. |
| 417 | unsigned int |
| 418 | output_section_count() const; |
| 419 | |
| 420 | private: |
| 421 | Output_segment(const Output_segment&); |
| 422 | Output_segment& operator=(const Output_segment&); |
| 423 | |
| 424 | typedef std::list<Output_data*> Output_data_list; |
| 425 | |
| 426 | // Set the section addresses in an Output_data_list. |
| 427 | uint64_t |
| 428 | set_section_list_addresses(Output_data_list*, uint64_t addr, off_t* poff); |
| 429 | |
| 430 | // Return the number of Output_sections in an Output_data_list. |
| 431 | unsigned int |
| 432 | output_section_count_list(const Output_data_list*) const; |
| 433 | |
| 434 | // The list of output data with contents attached to this segment. |
| 435 | Output_data_list output_data_; |
| 436 | // The list of output data without contents attached to this segment. |
| 437 | Output_data_list output_bss_; |
| 438 | // The segment virtual address. |
| 439 | uint64_t vaddr_; |
| 440 | // The segment physical address. |
| 441 | uint64_t paddr_; |
| 442 | // The size of the segment in memory. |
| 443 | uint64_t memsz_; |
| 444 | // The segment alignment. |
| 445 | uint64_t align_; |
| 446 | // The offset of the segment data within the file. |
| 447 | off_t offset_; |
| 448 | // The size of the segment data in the file. |
| 449 | off_t filesz_; |
| 450 | // The segment type; |
| 451 | elfcpp::Elf_Word type_; |
| 452 | // The segment flags. |
| 453 | elfcpp::Elf_Word flags_; |
| 454 | }; |
| 455 | |
| 456 | // This class represents the output file. The output file is a |
| 457 | // collection of output segments and a collection of output sections |
| 458 | // which are not associated with segments. |
| 459 | |
| 460 | class Output_file |
| 461 | { |
| 462 | public: |
| 463 | Output_file(); |
| 464 | ~Output_file(); |
| 465 | |
| 466 | // Write data to the output file. |
| 467 | void |
| 468 | write(off_t off, const void* data, off_t len); |
| 469 | }; |
| 470 | |
| 471 | } // End namespace gold. |
| 472 | |
| 473 | #endif // !defined(GOLD_OUTPUT_H) |