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a2fb1b05 ILT |
1 | // layout.h -- lay out output file sections for gold -*- C++ -*- |
2 | ||
6cb15b7f ILT |
3 | // Copyright 2006, 2007 Free Software Foundation, Inc. |
4 | // Written by Ian Lance Taylor <iant@google.com>. | |
5 | ||
6 | // This file is part of gold. | |
7 | ||
8 | // This program is free software; you can redistribute it and/or modify | |
9 | // it under the terms of the GNU General Public License as published by | |
10 | // the Free Software Foundation; either version 3 of the License, or | |
11 | // (at your option) any later version. | |
12 | ||
13 | // This program is distributed in the hope that it will be useful, | |
14 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | // GNU General Public License for more details. | |
17 | ||
18 | // You should have received a copy of the GNU General Public License | |
19 | // along with this program; if not, write to the Free Software | |
20 | // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, | |
21 | // MA 02110-1301, USA. | |
22 | ||
a2fb1b05 ILT |
23 | #ifndef GOLD_LAYOUT_H |
24 | #define GOLD_LAYOUT_H | |
25 | ||
26 | #include <list> | |
27 | #include <string> | |
28 | #include <utility> | |
29 | #include <vector> | |
30 | ||
a2fb1b05 ILT |
31 | #include "workqueue.h" |
32 | #include "object.h" | |
14b31740 | 33 | #include "dynobj.h" |
a2fb1b05 ILT |
34 | #include "stringpool.h" |
35 | ||
36 | namespace gold | |
37 | { | |
38 | ||
ead1e424 | 39 | class General_options; |
54dc6425 | 40 | class Input_objects; |
75f65a3e | 41 | class Symbol_table; |
ead1e424 | 42 | class Output_section_data; |
a2fb1b05 | 43 | class Output_section; |
75f65a3e | 44 | class Output_section_headers; |
a2fb1b05 | 45 | class Output_segment; |
54dc6425 | 46 | class Output_data; |
a3ad94ed | 47 | class Output_data_dynamic; |
61ba1cf9 | 48 | class Target; |
a2fb1b05 | 49 | |
92e059d8 ILT |
50 | // This task function handles mapping the input sections to output |
51 | // sections and laying them out in memory. | |
a2fb1b05 | 52 | |
92e059d8 | 53 | class Layout_task_runner : public Task_function_runner |
a2fb1b05 ILT |
54 | { |
55 | public: | |
56 | // OPTIONS is the command line options, INPUT_OBJECTS is the list of | |
92e059d8 ILT |
57 | // input objects, SYMTAB is the symbol table, LAYOUT is the layout |
58 | // object. | |
59 | Layout_task_runner(const General_options& options, | |
60 | const Input_objects* input_objects, | |
61 | Symbol_table* symtab, | |
62 | Layout* layout) | |
75f65a3e | 63 | : options_(options), input_objects_(input_objects), symtab_(symtab), |
92e059d8 | 64 | layout_(layout) |
a2fb1b05 ILT |
65 | { } |
66 | ||
92e059d8 | 67 | // Run the operation. |
a2fb1b05 ILT |
68 | void |
69 | run(Workqueue*); | |
70 | ||
71 | private: | |
92e059d8 ILT |
72 | Layout_task_runner(const Layout_task_runner&); |
73 | Layout_task_runner& operator=(const Layout_task_runner&); | |
a2fb1b05 ILT |
74 | |
75 | const General_options& options_; | |
54dc6425 | 76 | const Input_objects* input_objects_; |
75f65a3e | 77 | Symbol_table* symtab_; |
12e14209 | 78 | Layout* layout_; |
a2fb1b05 ILT |
79 | }; |
80 | ||
81 | // This class handles the details of laying out input sections. | |
82 | ||
83 | class Layout | |
84 | { | |
85 | public: | |
54dc6425 ILT |
86 | Layout(const General_options& options); |
87 | ||
ead1e424 ILT |
88 | // Given an input section SHNDX, named NAME, with data in SHDR, from |
89 | // the object file OBJECT, return the output section where this | |
90 | // input section should go. Set *OFFSET to the offset within the | |
91 | // output section. | |
a2fb1b05 ILT |
92 | template<int size, bool big_endian> |
93 | Output_section* | |
f6ce93d6 | 94 | layout(Relobj *object, unsigned int shndx, const char* name, |
a2fb1b05 ILT |
95 | const elfcpp::Shdr<size, big_endian>& shdr, off_t* offset); |
96 | ||
35cdfc9a ILT |
97 | // Handle a GNU stack note. This is called once per input object |
98 | // file. SEEN_GNU_STACK is true if the object file has a | |
99 | // .note.GNU-stack section. GNU_STACK_FLAGS is the section flags | |
100 | // from that section if there was one. | |
101 | void | |
102 | layout_gnu_stack(bool seen_gnu_stack, uint64_t gnu_stack_flags); | |
103 | ||
ead1e424 ILT |
104 | // Add an Output_section_data to the layout. This is used for |
105 | // special sections like the GOT section. | |
106 | void | |
107 | add_output_section_data(const char* name, elfcpp::Elf_Word type, | |
108 | elfcpp::Elf_Xword flags, | |
109 | Output_section_data*); | |
110 | ||
a3ad94ed ILT |
111 | // Create dynamic sections if necessary. |
112 | void | |
113 | create_initial_dynamic_sections(const Input_objects*, Symbol_table*); | |
114 | ||
bfd58944 ILT |
115 | // Define __start and __stop symbols for output sections. |
116 | void | |
117 | define_section_symbols(Symbol_table*, const Target*); | |
118 | ||
61ba1cf9 ILT |
119 | // Return the Stringpool used for symbol names. |
120 | const Stringpool* | |
121 | sympool() const | |
122 | { return &this->sympool_; } | |
123 | ||
16649710 ILT |
124 | // Return the Stringpool used for dynamic symbol names and dynamic |
125 | // tags. | |
126 | const Stringpool* | |
127 | dynpool() const | |
128 | { return &this->dynpool_; } | |
129 | ||
a2fb1b05 ILT |
130 | // Return whether a section is a .gnu.linkonce section, given the |
131 | // section name. | |
132 | static inline bool | |
133 | is_linkonce(const char* name) | |
134 | { return strncmp(name, ".gnu.linkonce", sizeof(".gnu.linkonce") - 1) == 0; } | |
135 | ||
136 | // Record the signature of a comdat section, and return whether to | |
137 | // include it in the link. The GROUP parameter is true for a | |
138 | // section group signature, false for a signature derived from a | |
139 | // .gnu.linkonce section. | |
140 | bool | |
141 | add_comdat(const char*, bool group); | |
142 | ||
54dc6425 | 143 | // Finalize the layout after all the input sections have been added. |
75f65a3e ILT |
144 | off_t |
145 | finalize(const Input_objects*, Symbol_table*); | |
54dc6425 | 146 | |
e44fcf3b ILT |
147 | // Return the size of the output file. |
148 | off_t | |
149 | output_file_size() const | |
150 | { return this->output_file_size_; } | |
151 | ||
16649710 ILT |
152 | // Return the TLS segment. This will return NULL if there isn't |
153 | // one. | |
92e059d8 ILT |
154 | Output_segment* |
155 | tls_segment() const | |
156 | { return this->tls_segment_; } | |
157 | ||
16649710 ILT |
158 | // Return the normal symbol table. |
159 | Output_section* | |
160 | symtab_section() const | |
161 | { | |
162 | gold_assert(this->symtab_section_ != NULL); | |
163 | return this->symtab_section_; | |
164 | } | |
165 | ||
166 | // Return the dynamic symbol table. | |
167 | Output_section* | |
168 | dynsym_section() const | |
169 | { | |
170 | gold_assert(this->dynsym_section_ != NULL); | |
171 | return this->dynsym_section_; | |
172 | } | |
173 | ||
174 | // Return the dynamic tags. | |
175 | Output_data_dynamic* | |
176 | dynamic_data() const | |
177 | { return this->dynamic_data_; } | |
178 | ||
61ba1cf9 ILT |
179 | // Write out data not associated with an input file or the symbol |
180 | // table. | |
181 | void | |
9025d29d | 182 | write_data(const Symbol_table*, Output_file*) const; |
61ba1cf9 | 183 | |
ead1e424 ILT |
184 | // Return an output section named NAME, or NULL if there is none. |
185 | Output_section* | |
186 | find_output_section(const char* name) const; | |
187 | ||
188 | // Return an output segment of type TYPE, with segment flags SET set | |
189 | // and segment flags CLEAR clear. Return NULL if there is none. | |
190 | Output_segment* | |
191 | find_output_segment(elfcpp::PT type, elfcpp::Elf_Word set, | |
192 | elfcpp::Elf_Word clear) const; | |
193 | ||
54dc6425 ILT |
194 | // The list of segments. |
195 | ||
196 | typedef std::vector<Output_segment*> Segment_list; | |
197 | ||
198 | // The list of sections not attached to a segment. | |
199 | ||
a3ad94ed | 200 | typedef std::vector<Output_section*> Section_list; |
54dc6425 ILT |
201 | |
202 | // The list of information to write out which is not attached to | |
203 | // either a section or a segment. | |
a3ad94ed | 204 | typedef std::vector<Output_data*> Data_list; |
54dc6425 | 205 | |
a2fb1b05 ILT |
206 | private: |
207 | Layout(const Layout&); | |
208 | Layout& operator=(const Layout&); | |
209 | ||
210 | // Mapping from .gnu.linkonce section names to output section names. | |
211 | struct Linkonce_mapping | |
212 | { | |
213 | const char* from; | |
214 | int fromlen; | |
215 | const char* to; | |
ead1e424 | 216 | int tolen; |
a2fb1b05 ILT |
217 | }; |
218 | static const Linkonce_mapping linkonce_mapping[]; | |
219 | static const int linkonce_mapping_count; | |
220 | ||
3151305a ILT |
221 | // Handle an exception frame section. |
222 | template<int size, bool big_endian> | |
223 | void | |
224 | layout_eh_frame(Relobj*, unsigned int, const char*, | |
225 | const elfcpp::Shdr<size, big_endian>&, | |
226 | Output_section*, off_t*); | |
227 | ||
4f211c8b ILT |
228 | // Create a .note section for gold. |
229 | void | |
35cdfc9a ILT |
230 | create_gold_note(); |
231 | ||
232 | // Record whether the stack must be executable. | |
233 | void | |
234 | create_executable_stack_info(const Target*); | |
4f211c8b | 235 | |
75f65a3e ILT |
236 | // Find the first read-only PT_LOAD segment, creating one if |
237 | // necessary. | |
238 | Output_segment* | |
239 | find_first_load_seg(); | |
240 | ||
54dc6425 ILT |
241 | // Create the output sections for the symbol table. |
242 | void | |
9025d29d | 243 | create_symtab_sections(const Input_objects*, Symbol_table*, off_t*); |
54dc6425 | 244 | |
75f65a3e ILT |
245 | // Create the .shstrtab section. |
246 | Output_section* | |
247 | create_shstrtab(); | |
248 | ||
249 | // Create the section header table. | |
250 | Output_section_headers* | |
9025d29d | 251 | create_shdrs(off_t*); |
54dc6425 | 252 | |
dbe717ef ILT |
253 | // Create the dynamic symbol table. |
254 | void | |
14b31740 ILT |
255 | create_dynamic_symtab(const Target*, Symbol_table*, Output_section** pdynstr, |
256 | unsigned int* plocal_dynamic_count, | |
257 | std::vector<Symbol*>* pdynamic_symbols, | |
258 | Versions* versions); | |
dbe717ef | 259 | |
a3ad94ed | 260 | // Finish the .dynamic section and PT_DYNAMIC segment. |
dbe717ef | 261 | void |
16649710 | 262 | finish_dynamic_section(const Input_objects*, const Symbol_table*); |
dbe717ef ILT |
263 | |
264 | // Create the .interp section and PT_INTERP segment. | |
265 | void | |
266 | create_interp(const Target* target); | |
267 | ||
14b31740 ILT |
268 | // Create the version sections. |
269 | void | |
9025d29d | 270 | create_version_sections(const Versions*, |
46fe1623 | 271 | const Symbol_table*, |
14b31740 ILT |
272 | unsigned int local_symcount, |
273 | const std::vector<Symbol*>& dynamic_symbols, | |
274 | const Output_section* dynstr); | |
275 | ||
276 | template<int size, bool big_endian> | |
277 | void | |
278 | sized_create_version_sections(const Versions* versions, | |
46fe1623 | 279 | const Symbol_table*, |
14b31740 ILT |
280 | unsigned int local_symcount, |
281 | const std::vector<Symbol*>& dynamic_symbols, | |
91da9340 ILT |
282 | const Output_section* dynstr |
283 | ACCEPT_SIZE_ENDIAN); | |
14b31740 | 284 | |
a2fb1b05 ILT |
285 | // Return whether to include this section in the link. |
286 | template<int size, bool big_endian> | |
287 | bool | |
288 | include_section(Object* object, const char* name, | |
289 | const elfcpp::Shdr<size, big_endian>&); | |
290 | ||
ead1e424 ILT |
291 | // Return the output section name to use given an input section |
292 | // name. Set *PLEN to the length of the name. *PLEN must be | |
293 | // initialized to the length of NAME. | |
294 | static const char* | |
295 | output_section_name(const char* name, size_t* plen); | |
296 | ||
a2fb1b05 | 297 | // Return the output section name to use for a linkonce section |
ead1e424 | 298 | // name. PLEN is as for output_section_name. |
a2fb1b05 | 299 | static const char* |
ead1e424 ILT |
300 | linkonce_output_name(const char* name, size_t* plen); |
301 | ||
302 | // Return the output section for NAME, TYPE and FLAGS. | |
303 | Output_section* | |
f0641a0b ILT |
304 | get_output_section(const char* name, Stringpool::Key name_key, |
305 | elfcpp::Elf_Word type, elfcpp::Elf_Xword flags); | |
a2fb1b05 ILT |
306 | |
307 | // Create a new Output_section. | |
308 | Output_section* | |
309 | make_output_section(const char* name, elfcpp::Elf_Word type, | |
310 | elfcpp::Elf_Xword flags); | |
311 | ||
dbe717ef ILT |
312 | // Set the final file offsets of all the segments. |
313 | off_t | |
314 | set_segment_offsets(const Target*, Output_segment*, unsigned int* pshndx); | |
315 | ||
14b31740 | 316 | // Set the final file offsets and section indexes of all the |
dbe717ef ILT |
317 | // sections not associated with a segment. |
318 | off_t | |
319 | set_section_offsets(off_t, unsigned int *pshndx); | |
320 | ||
a2fb1b05 ILT |
321 | // Return whether SEG1 comes before SEG2 in the output file. |
322 | static bool | |
b3168e9d | 323 | segment_precedes(const Output_segment* seg1, const Output_segment* seg2); |
a2fb1b05 ILT |
324 | |
325 | // Map from section flags to segment flags. | |
326 | static elfcpp::Elf_Word | |
327 | section_flags_to_segment(elfcpp::Elf_Xword flags); | |
328 | ||
329 | // A mapping used for group signatures. | |
330 | typedef Unordered_map<std::string, bool> Signatures; | |
331 | ||
332 | // Mapping from input section name/type/flags to output section. We | |
333 | // use canonicalized strings here. | |
334 | ||
f0641a0b | 335 | typedef std::pair<Stringpool::Key, |
a2fb1b05 ILT |
336 | std::pair<elfcpp::Elf_Word, elfcpp::Elf_Xword> > Key; |
337 | ||
338 | struct Hash_key | |
339 | { | |
340 | size_t | |
341 | operator()(const Key& k) const; | |
342 | }; | |
343 | ||
344 | typedef Unordered_map<Key, Output_section*, Hash_key> Section_name_map; | |
345 | ||
346 | // A comparison class for segments. | |
347 | ||
348 | struct Compare_segments | |
349 | { | |
350 | bool | |
351 | operator()(const Output_segment* seg1, const Output_segment* seg2) | |
352 | { return Layout::segment_precedes(seg1, seg2); } | |
353 | }; | |
354 | ||
a2fb1b05 ILT |
355 | // A reference to the options on the command line. |
356 | const General_options& options_; | |
357 | // The output section names. | |
358 | Stringpool namepool_; | |
75f65a3e ILT |
359 | // The output symbol names. |
360 | Stringpool sympool_; | |
a3ad94ed ILT |
361 | // The dynamic strings, if needed. |
362 | Stringpool dynpool_; | |
a2fb1b05 ILT |
363 | // The list of group sections and linkonce sections which we have seen. |
364 | Signatures signatures_; | |
365 | // The mapping from input section name/type/flags to output sections. | |
366 | Section_name_map section_name_map_; | |
367 | // The list of output segments. | |
368 | Segment_list segment_list_; | |
a3ad94ed ILT |
369 | // The list of output sections. |
370 | Section_list section_list_; | |
a2fb1b05 ILT |
371 | // The list of output sections which are not attached to any output |
372 | // segment. | |
a3ad94ed ILT |
373 | Section_list unattached_section_list_; |
374 | // The list of unattached Output_data objects which require special | |
375 | // handling because they are not Output_sections. | |
61ba1cf9 | 376 | Data_list special_output_list_; |
92e059d8 ILT |
377 | // A pointer to the PT_TLS segment if there is one. |
378 | Output_segment* tls_segment_; | |
a3ad94ed ILT |
379 | // The SHT_SYMTAB output section. |
380 | Output_section* symtab_section_; | |
381 | // The SHT_DYNSYM output section if there is one. | |
382 | Output_section* dynsym_section_; | |
383 | // The SHT_DYNAMIC output section if there is one. | |
384 | Output_section* dynamic_section_; | |
16649710 ILT |
385 | // The dynamic data which goes into dynamic_section_. |
386 | Output_data_dynamic* dynamic_data_; | |
3151305a ILT |
387 | // The exception frame section. |
388 | Output_section* eh_frame_section_; | |
e44fcf3b ILT |
389 | // The size of the output file. |
390 | off_t output_file_size_; | |
35cdfc9a ILT |
391 | // Whether we have seen an object file marked to require an |
392 | // executable stack. | |
393 | bool input_requires_executable_stack_; | |
394 | // Whether we have seen at least one object file with an executable | |
395 | // stack marker. | |
396 | bool input_with_gnu_stack_note_; | |
397 | // Whether we have seen at least one object file without an | |
398 | // executable stack marker. | |
399 | bool input_without_gnu_stack_note_; | |
61ba1cf9 ILT |
400 | }; |
401 | ||
402 | // This task handles writing out data which is not part of a section | |
403 | // or segment. | |
404 | ||
405 | class Write_data_task : public Task | |
406 | { | |
407 | public: | |
a3ad94ed | 408 | Write_data_task(const Layout* layout, const Symbol_table* symtab, |
9025d29d ILT |
409 | Output_file* of, Task_token* final_blocker) |
410 | : layout_(layout), symtab_(symtab), of_(of), final_blocker_(final_blocker) | |
61ba1cf9 ILT |
411 | { } |
412 | ||
413 | // The standard Task methods. | |
414 | ||
415 | Is_runnable_type | |
416 | is_runnable(Workqueue*); | |
417 | ||
418 | Task_locker* | |
419 | locks(Workqueue*); | |
420 | ||
421 | void | |
422 | run(Workqueue*); | |
423 | ||
424 | private: | |
425 | const Layout* layout_; | |
a3ad94ed | 426 | const Symbol_table* symtab_; |
61ba1cf9 ILT |
427 | Output_file* of_; |
428 | Task_token* final_blocker_; | |
429 | }; | |
430 | ||
431 | // This task handles writing out the global symbols. | |
432 | ||
433 | class Write_symbols_task : public Task | |
434 | { | |
435 | public: | |
436 | Write_symbols_task(const Symbol_table* symtab, const Target* target, | |
16649710 ILT |
437 | const Stringpool* sympool, const Stringpool* dynpool, |
438 | Output_file* of, Task_token* final_blocker) | |
439 | : symtab_(symtab), target_(target), sympool_(sympool), dynpool_(dynpool), | |
440 | of_(of), final_blocker_(final_blocker) | |
61ba1cf9 ILT |
441 | { } |
442 | ||
443 | // The standard Task methods. | |
444 | ||
445 | Is_runnable_type | |
446 | is_runnable(Workqueue*); | |
447 | ||
448 | Task_locker* | |
449 | locks(Workqueue*); | |
450 | ||
451 | void | |
452 | run(Workqueue*); | |
453 | ||
454 | private: | |
455 | const Symbol_table* symtab_; | |
456 | const Target* target_; | |
457 | const Stringpool* sympool_; | |
16649710 | 458 | const Stringpool* dynpool_; |
61ba1cf9 ILT |
459 | Output_file* of_; |
460 | Task_token* final_blocker_; | |
461 | }; | |
462 | ||
92e059d8 | 463 | // This task function handles closing the file. |
61ba1cf9 | 464 | |
92e059d8 | 465 | class Close_task_runner : public Task_function_runner |
61ba1cf9 ILT |
466 | { |
467 | public: | |
92e059d8 ILT |
468 | Close_task_runner(Output_file* of) |
469 | : of_(of) | |
61ba1cf9 ILT |
470 | { } |
471 | ||
92e059d8 | 472 | // Run the operation. |
61ba1cf9 ILT |
473 | void |
474 | run(Workqueue*); | |
475 | ||
476 | private: | |
477 | Output_file* of_; | |
a2fb1b05 ILT |
478 | }; |
479 | ||
ead1e424 ILT |
480 | // A small helper function to align an address. |
481 | ||
482 | inline uint64_t | |
483 | align_address(uint64_t address, uint64_t addralign) | |
484 | { | |
485 | if (addralign != 0) | |
486 | address = (address + addralign - 1) &~ (addralign - 1); | |
487 | return address; | |
488 | } | |
489 | ||
a2fb1b05 ILT |
490 | } // End namespace gold. |
491 | ||
492 | #endif // !defined(GOLD_LAYOUT_H) |