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bae7f79e ILT |
1 | // object.h -- support for an object file for linking in gold -*- C++ -*- |
2 | ||
3 | #ifndef GOLD_OBJECT_H | |
4 | #define GOLD_OBJECT_H | |
5 | ||
14bfc3f5 | 6 | #include <cassert> |
a2fb1b05 | 7 | #include <vector> |
14bfc3f5 | 8 | |
bae7f79e | 9 | #include "elfcpp.h" |
bae7f79e | 10 | #include "fileread.h" |
14bfc3f5 ILT |
11 | #include "target.h" |
12 | #include "symtab.h" | |
bae7f79e ILT |
13 | |
14 | namespace gold | |
15 | { | |
16 | ||
75f65a3e | 17 | class Stringpool; |
a2fb1b05 | 18 | class Layout; |
61ba1cf9 ILT |
19 | class Output_section; |
20 | class Output_file; | |
a2fb1b05 | 21 | |
bae7f79e ILT |
22 | // Data to pass from read_symbols() to add_symbols(). |
23 | ||
24 | struct Read_symbols_data | |
25 | { | |
26 | // Symbol data. | |
27 | File_view* symbols; | |
28 | // Size of symbol data in bytes. | |
29 | off_t symbols_size; | |
30 | // Symbol names. | |
31 | File_view* symbol_names; | |
32 | // Size of symbol name data in bytes. | |
33 | off_t symbol_names_size; | |
34 | }; | |
35 | ||
36 | // Object is an interface which represents either a 32-bit or a 64-bit | |
14bfc3f5 ILT |
37 | // input object. This can be a regular object file (ET_REL) or a |
38 | // shared object (ET_DYN). The actual instantiations are | |
39 | // Sized_object<32> and Sized_object<64> | |
bae7f79e ILT |
40 | |
41 | class Object | |
42 | { | |
43 | public: | |
44 | // NAME is the name of the object as we would report it to the user | |
45 | // (e.g., libfoo.a(bar.o) if this is in an archive. INPUT_FILE is | |
46 | // used to read the file. OFFSET is the offset within the input | |
47 | // file--0 for a .o or .so file, something else for a .a file. | |
14bfc3f5 ILT |
48 | Object(const std::string& name, Input_file* input_file, bool is_dynamic, |
49 | off_t offset = 0) | |
50 | : name_(name), input_file_(input_file), offset_(offset), | |
a2fb1b05 ILT |
51 | shnum_(0), is_dynamic_(is_dynamic), target_(NULL), |
52 | map_to_output_() | |
bae7f79e ILT |
53 | { } |
54 | ||
55 | virtual ~Object() | |
56 | { } | |
57 | ||
14bfc3f5 | 58 | // Return the name of the object as we would report it to the tuser. |
bae7f79e ILT |
59 | const std::string& |
60 | name() const | |
61 | { return this->name_; } | |
62 | ||
14bfc3f5 ILT |
63 | // Return whether this is a dynamic object. |
64 | bool | |
65 | is_dynamic() const | |
66 | { return this->is_dynamic_; } | |
67 | ||
14bfc3f5 ILT |
68 | // Return the target structure associated with this object. |
69 | Target* | |
a2fb1b05 | 70 | target() const |
14bfc3f5 ILT |
71 | { return this->target_; } |
72 | ||
a2fb1b05 ILT |
73 | // Lock the underlying file. |
74 | void | |
75 | lock() | |
76 | { this->input_file_->file().lock(); } | |
77 | ||
78 | // Unlock the underlying file. | |
79 | void | |
80 | unlock() | |
81 | { this->input_file_->file().unlock(); } | |
82 | ||
83 | // Return whether the underlying file is locked. | |
84 | bool | |
85 | is_locked() const | |
86 | { return this->input_file_->file().is_locked(); } | |
87 | ||
d288e464 | 88 | #ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS |
14bfc3f5 ILT |
89 | // Return the sized target structure associated with this object. |
90 | // This is like the target method but it returns a pointer of | |
91 | // appropriate checked type. | |
92 | template<int size, bool big_endian> | |
93 | Sized_target<size, big_endian>* | |
94 | sized_target(); | |
d288e464 | 95 | #endif |
bae7f79e | 96 | |
a2fb1b05 ILT |
97 | // Read the symbol and relocation information. |
98 | Read_symbols_data | |
99 | read_symbols() | |
100 | { return this->do_read_symbols(); } | |
101 | ||
102 | // Add symbol information to the global symbol table. | |
103 | void | |
104 | add_symbols(Symbol_table* symtab, Read_symbols_data rd) | |
105 | { this->do_add_symbols(symtab, rd); } | |
106 | ||
107 | // Pass sections which should be included in the link to the Layout | |
108 | // object, and record where the sections go in the output file. | |
109 | void | |
110 | layout(Layout* lay) | |
111 | { this->do_layout(lay); } | |
112 | ||
75f65a3e ILT |
113 | // Initial local symbol processing: set the offset where local |
114 | // symbol information will be stored; add local symbol names to | |
115 | // *POOL; return the offset following the local symbols. | |
116 | off_t | |
117 | finalize_local_symbols(off_t off, Stringpool* pool) | |
118 | { return this->do_finalize_local_symbols(off, pool); } | |
119 | ||
61ba1cf9 ILT |
120 | // Relocate the input sections and write out the local symbols. |
121 | void | |
122 | relocate(const General_options& options, const Symbol_table* symtab, | |
123 | const Stringpool* sympool, Output_file* of) | |
124 | { return this->do_relocate(options, symtab, sympool, of); } | |
125 | ||
a2fb1b05 ILT |
126 | // What we need to know to map an input section to an output |
127 | // section. We keep an array of these, one for each input section, | |
128 | // indexed by the input section number. | |
129 | struct Map_to_output | |
130 | { | |
131 | // The output section. This is NULL if the input section is to be | |
132 | // discarded. | |
133 | Output_section* output_section; | |
134 | // The offset within the output section. | |
135 | off_t offset; | |
136 | }; | |
137 | ||
75f65a3e ILT |
138 | // Given a section index, return the corresponding Map_to_output |
139 | // information. | |
140 | const Map_to_output* | |
141 | section_output_info(unsigned int shnum) const | |
61ba1cf9 ILT |
142 | { |
143 | assert(shnum < this->map_to_output_.size()); | |
144 | return &this->map_to_output_[shnum]; | |
145 | } | |
75f65a3e ILT |
146 | |
147 | protected: | |
bae7f79e ILT |
148 | // Read the symbols--implemented by child class. |
149 | virtual Read_symbols_data | |
150 | do_read_symbols() = 0; | |
151 | ||
152 | // Add symbol information to the global symbol table--implemented by | |
153 | // child class. | |
154 | virtual void | |
14bfc3f5 | 155 | do_add_symbols(Symbol_table*, Read_symbols_data) = 0; |
bae7f79e | 156 | |
a2fb1b05 ILT |
157 | // Lay out sections--implemented by child class. |
158 | virtual void | |
159 | do_layout(Layout*) = 0; | |
160 | ||
75f65a3e ILT |
161 | // Finalize local symbols--implemented by child class. |
162 | virtual off_t | |
163 | do_finalize_local_symbols(off_t, Stringpool*) = 0; | |
164 | ||
61ba1cf9 ILT |
165 | // Relocate the input sections and write out the local |
166 | // symbols--implemented by child class. | |
167 | virtual void | |
168 | do_relocate(const General_options& options, const Symbol_table* symtab, | |
169 | const Stringpool*, Output_file* of) = 0; | |
170 | ||
bae7f79e ILT |
171 | // Get the file. |
172 | Input_file* | |
173 | input_file() const | |
174 | { return this->input_file_; } | |
175 | ||
176 | // Get the offset into the file. | |
177 | off_t | |
178 | offset() const | |
179 | { return this->offset_; } | |
180 | ||
181 | // Get a view into the underlying file. | |
182 | const unsigned char* | |
183 | get_view(off_t start, off_t size); | |
184 | ||
a2fb1b05 ILT |
185 | // Get the number of sections. |
186 | unsigned int | |
75f65a3e | 187 | shnum() const |
a2fb1b05 ILT |
188 | { return this->shnum_; } |
189 | ||
190 | // Set the number of sections. | |
191 | void | |
192 | set_shnum(int shnum) | |
193 | { this->shnum_ = shnum; } | |
194 | ||
14bfc3f5 ILT |
195 | // Set the target. |
196 | void | |
197 | set_target(Target* target) | |
198 | { this->target_ = target; } | |
199 | ||
bae7f79e ILT |
200 | // Read data from the underlying file. |
201 | void | |
202 | read(off_t start, off_t size, void* p); | |
203 | ||
204 | // Get a lasting view into the underlying file. | |
205 | File_view* | |
206 | get_lasting_view(off_t start, off_t size); | |
207 | ||
a2fb1b05 ILT |
208 | // Return the vector mapping input sections to output sections. |
209 | std::vector<Map_to_output>& | |
210 | map_to_output() | |
211 | { return this->map_to_output_; } | |
212 | ||
bae7f79e ILT |
213 | private: |
214 | // This class may not be copied. | |
215 | Object(const Object&); | |
216 | Object& operator=(const Object&); | |
217 | ||
61ba1cf9 | 218 | // Name of object as printed to user. |
bae7f79e ILT |
219 | std::string name_; |
220 | // For reading the file. | |
221 | Input_file* input_file_; | |
222 | // Offset within the file--0 for an object file, non-0 for an | |
223 | // archive. | |
224 | off_t offset_; | |
a2fb1b05 ILT |
225 | // Number of input sections. |
226 | unsigned int shnum_; | |
14bfc3f5 ILT |
227 | // Whether this is a dynamic object. |
228 | bool is_dynamic_; | |
229 | // Target functions--may be NULL if the target is not known. | |
230 | Target* target_; | |
a2fb1b05 ILT |
231 | // Mapping from input sections to output section. |
232 | std::vector<Map_to_output> map_to_output_; | |
bae7f79e ILT |
233 | }; |
234 | ||
d288e464 ILT |
235 | #ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS |
236 | ||
14bfc3f5 ILT |
237 | // Implement sized_target inline for efficiency. This approach breaks |
238 | // static type checking, but is made safe using asserts. | |
239 | ||
240 | template<int size, bool big_endian> | |
241 | inline Sized_target<size, big_endian>* | |
242 | Object::sized_target() | |
243 | { | |
244 | assert(this->target_->get_size() == size); | |
245 | assert(this->target_->is_big_endian() ? big_endian : !big_endian); | |
246 | return static_cast<Sized_target<size, big_endian>*>(this->target_); | |
247 | } | |
248 | ||
d288e464 ILT |
249 | #endif |
250 | ||
14bfc3f5 | 251 | // A regular object file. This is size and endian specific. |
bae7f79e ILT |
252 | |
253 | template<int size, bool big_endian> | |
254 | class Sized_object : public Object | |
255 | { | |
256 | public: | |
257 | Sized_object(const std::string& name, Input_file* input_file, off_t offset, | |
258 | const typename elfcpp::Ehdr<size, big_endian>&); | |
259 | ||
260 | ~Sized_object(); | |
261 | ||
a2fb1b05 | 262 | // Set up the object file based on the ELF header. |
bae7f79e ILT |
263 | void |
264 | setup(const typename elfcpp::Ehdr<size, big_endian>&); | |
265 | ||
a2fb1b05 | 266 | // Read the symbols. |
bae7f79e ILT |
267 | Read_symbols_data |
268 | do_read_symbols(); | |
269 | ||
a2fb1b05 | 270 | // Add the symbols to the symbol table. |
bae7f79e | 271 | void |
14bfc3f5 ILT |
272 | do_add_symbols(Symbol_table*, Read_symbols_data); |
273 | ||
a2fb1b05 ILT |
274 | // Lay out the input sections. |
275 | void | |
276 | do_layout(Layout*); | |
277 | ||
75f65a3e ILT |
278 | // Finalize the local symbols. |
279 | off_t | |
280 | do_finalize_local_symbols(off_t, Stringpool*); | |
281 | ||
61ba1cf9 ILT |
282 | // Relocate the input sections and write out the local symbols. |
283 | void | |
284 | do_relocate(const General_options& options, const Symbol_table* symtab, | |
285 | const Stringpool*, Output_file* of); | |
286 | ||
a2fb1b05 | 287 | // Return the appropriate Sized_target structure. |
14bfc3f5 ILT |
288 | Sized_target<size, big_endian>* |
289 | sized_target() | |
274e99f9 ILT |
290 | { |
291 | #ifdef HAVE_MEMBER_TEMPLATE_SPECIFICATIONS | |
292 | return this->Object::sized_target<size, big_endian>(); | |
293 | #else | |
294 | return static_cast<Sized_target<size, big_endian>*>(this->target()); | |
295 | #endif | |
296 | } | |
bae7f79e ILT |
297 | |
298 | private: | |
299 | // This object may not be copied. | |
300 | Sized_object(const Sized_object&); | |
301 | Sized_object& operator=(const Sized_object&); | |
302 | ||
a2fb1b05 ILT |
303 | // For convenience. |
304 | typedef Sized_object<size, big_endian> This; | |
305 | static const int ehdr_size = elfcpp::Elf_sizes<size>::ehdr_size; | |
306 | static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; | |
307 | static const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
75f65a3e ILT |
308 | typedef elfcpp::Shdr<size, big_endian> Shdr; |
309 | ||
310 | // Read the section header for section SHNUM. | |
311 | const unsigned char* | |
312 | section_header(unsigned int shnum); | |
a2fb1b05 ILT |
313 | |
314 | // Whether to include a section group in the link. | |
315 | bool | |
316 | include_section_group(Layout*, unsigned int, | |
317 | const elfcpp::Shdr<size, big_endian>&, | |
318 | std::vector<bool>*); | |
319 | ||
320 | // Whether to include a linkonce section in the link. | |
321 | bool | |
322 | include_linkonce_section(Layout*, const char*, | |
323 | const elfcpp::Shdr<size, big_endian>&); | |
324 | ||
61ba1cf9 ILT |
325 | // Views and sizes when relocating. |
326 | struct View_size | |
327 | { | |
328 | unsigned char* view; | |
329 | typename elfcpp::Elf_types<size>::Elf_Addr address; | |
330 | off_t offset; | |
331 | off_t view_size; | |
332 | }; | |
333 | ||
334 | typedef std::vector<View_size> Views; | |
335 | ||
336 | // Write section data to the output file. Record the views and | |
337 | // sizes in VIEWS for use when relocating. | |
338 | void | |
339 | write_sections(const unsigned char* pshdrs, Output_file*, Views*); | |
340 | ||
341 | // Relocate the sections in the output file. | |
342 | void | |
343 | relocate_sections(const Symbol_table*, const unsigned char* pshdrs, Views*); | |
344 | ||
345 | // Write out the local symbols. | |
346 | void | |
347 | write_local_symbols(Output_file*, const Stringpool*); | |
348 | ||
bae7f79e ILT |
349 | // ELF file header e_flags field. |
350 | unsigned int flags_; | |
bae7f79e ILT |
351 | // File offset of section header table. |
352 | off_t shoff_; | |
bae7f79e ILT |
353 | // Offset of SHT_STRTAB section holding section names. |
354 | unsigned int shstrndx_; | |
355 | // Index of SHT_SYMTAB section. | |
356 | unsigned int symtab_shnum_; | |
61ba1cf9 ILT |
357 | // The number of local symbols. |
358 | unsigned int local_symbol_count_; | |
359 | // The number of local symbols which go into the output file. | |
360 | unsigned int output_local_symbol_count_; | |
14bfc3f5 ILT |
361 | // The entries in the symbol table for the external symbols. |
362 | Symbol** symbols_; | |
75f65a3e ILT |
363 | // File offset for local symbols. |
364 | off_t local_symbol_offset_; | |
61ba1cf9 ILT |
365 | // Values of local symbols. |
366 | typename elfcpp::Elf_types<size>::Elf_Addr *values_; | |
bae7f79e ILT |
367 | }; |
368 | ||
54dc6425 | 369 | // A class to manage the list of all objects. |
a2fb1b05 | 370 | |
54dc6425 ILT |
371 | class Input_objects |
372 | { | |
373 | public: | |
374 | Input_objects() | |
75f65a3e | 375 | : object_list_(), target_(NULL), any_dynamic_(false) |
54dc6425 ILT |
376 | { } |
377 | ||
378 | // The type of the list of input objects. | |
379 | typedef std::list<Object*> Object_list; | |
380 | ||
381 | // Add an object to the list. | |
382 | void | |
383 | add_object(Object*); | |
384 | ||
75f65a3e ILT |
385 | // Get the target we should use for the output file. |
386 | Target* | |
387 | target() const | |
388 | { return this->target_; } | |
389 | ||
54dc6425 ILT |
390 | // Iterate over all objects. |
391 | Object_list::const_iterator | |
392 | begin() const | |
393 | { return this->object_list_.begin(); } | |
394 | ||
395 | Object_list::const_iterator | |
396 | end() const | |
397 | { return this->object_list_.end(); } | |
398 | ||
399 | // Return whether we have seen any dynamic objects. | |
400 | bool | |
401 | any_dynamic() const | |
402 | { return this->any_dynamic_; } | |
403 | ||
404 | private: | |
405 | Input_objects(const Input_objects&); | |
406 | Input_objects& operator=(const Input_objects&); | |
407 | ||
408 | Object_list object_list_; | |
75f65a3e | 409 | Target* target_; |
54dc6425 ILT |
410 | bool any_dynamic_; |
411 | }; | |
a2fb1b05 | 412 | |
bae7f79e ILT |
413 | // Return an Object appropriate for the input file. P is BYTES long, |
414 | // and holds the ELF header. | |
415 | ||
61ba1cf9 ILT |
416 | extern Object* |
417 | make_elf_object(const std::string& name, Input_file*, | |
418 | off_t offset, const unsigned char* p, | |
419 | off_t bytes); | |
bae7f79e ILT |
420 | |
421 | } // end namespace gold | |
422 | ||
423 | #endif // !defined(GOLD_OBJECT_H) |