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1 | // dynobj.h -- dynamic object support for gold -*- C++ -*- |
2 | ||
3 | #ifndef GOLD_DYNOBJ_H | |
4 | #define GOLD_DYNOBJ_H | |
5 | ||
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6 | #include <vector> |
7 | ||
14b31740 | 8 | #include "stringpool.h" |
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9 | #include "object.h" |
10 | ||
11 | namespace gold | |
12 | { | |
13 | ||
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14 | class General_options; |
15 | class Stringpool; | |
16 | ||
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17 | // A dynamic object (ET_DYN). This is an abstract base class itself. |
18 | // The implementations is the template class Sized_dynobj. | |
19 | ||
20 | class Dynobj : public Object | |
21 | { | |
22 | public: | |
23 | Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0) | |
a3ad94ed | 24 | : Object(name, input_file, true, offset), soname_() |
f6ce93d6 | 25 | { } |
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26 | |
27 | // Return the name to use in a DT_NEEDED entry for this object. | |
28 | const char* | |
29 | soname() const; | |
30 | ||
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31 | // Compute the ELF hash code for a string. |
32 | static uint32_t | |
33 | elf_hash(const char*); | |
34 | ||
a3ad94ed ILT |
35 | // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN. |
36 | // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the | |
37 | // number of local dynamic symbols, which is the index of the first | |
38 | // dynamic gobal symbol. | |
39 | static void | |
40 | create_elf_hash_table(const Target*, const std::vector<Symbol*>& dynsyms, | |
41 | unsigned int local_dynsym_count, | |
42 | unsigned char** pphash, | |
43 | unsigned int* phashlen); | |
44 | ||
45 | // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS | |
46 | // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number | |
47 | // of local dynamic symbols, which is the index of the first dynamic | |
48 | // gobal symbol. | |
49 | static void | |
50 | create_gnu_hash_table(const Target*, const std::vector<Symbol*>& dynsyms, | |
51 | unsigned int local_dynsym_count, | |
52 | unsigned char** pphash, unsigned int* phashlen); | |
53 | ||
54 | protected: | |
55 | // Set the DT_SONAME string. | |
56 | void | |
57 | set_soname_string(const char* s) | |
58 | { this->soname_.assign(s); } | |
59 | ||
60 | private: | |
a3ad94ed ILT |
61 | // Compute the GNU hash code for a string. |
62 | static uint32_t | |
63 | gnu_hash(const char*); | |
64 | ||
65 | // Compute the number of hash buckets to use. | |
66 | static unsigned int | |
67 | compute_bucket_count(const std::vector<uint32_t>& hashcodes, | |
68 | bool for_gnu_hash_table); | |
69 | ||
70 | // Sized version of create_elf_hash_table. | |
71 | template<bool big_endian> | |
72 | static void | |
73 | sized_create_elf_hash_table(const std::vector<uint32_t>& bucket, | |
74 | const std::vector<uint32_t>& chain, | |
75 | unsigned char* phash, | |
76 | unsigned int hashlen); | |
77 | ||
78 | // Sized version of create_gnu_hash_table. | |
79 | template<int size, bool big_endian> | |
80 | static void | |
81 | sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms, | |
82 | const std::vector<uint32_t>& dynsym_hashvals, | |
83 | unsigned int unhashed_dynsym_count, | |
84 | unsigned char** pphash, | |
85 | unsigned int* phashlen); | |
86 | ||
87 | // The DT_SONAME name, if any. | |
88 | std::string soname_; | |
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89 | }; |
90 | ||
91 | // A dynamic object, size and endian specific version. | |
92 | ||
93 | template<int size, bool big_endian> | |
94 | class Sized_dynobj : public Dynobj | |
95 | { | |
96 | public: | |
97 | Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset, | |
98 | const typename elfcpp::Ehdr<size, big_endian>&); | |
99 | ||
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100 | // Set up the object file based on the ELF header. |
101 | void | |
102 | setup(const typename elfcpp::Ehdr<size, big_endian>&); | |
103 | ||
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104 | // Read the symbols. |
105 | void | |
106 | do_read_symbols(Read_symbols_data*); | |
107 | ||
108 | // Lay out the input sections. | |
109 | void | |
110 | do_layout(const General_options&, Symbol_table*, Layout*, | |
111 | Read_symbols_data*); | |
112 | ||
113 | // Add the symbols to the symbol table. | |
114 | void | |
115 | do_add_symbols(Symbol_table*, Read_symbols_data*); | |
116 | ||
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117 | // Get the name of a section. |
118 | std::string | |
119 | do_section_name(unsigned int shndx) | |
120 | { return this->elf_file_.section_name(shndx); } | |
121 | ||
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122 | // Return a view of the contents of a section. Set *PLEN to the |
123 | // size. | |
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124 | Object::Location |
125 | do_section_contents(unsigned int shndx) | |
126 | { return this->elf_file_.section_contents(shndx); } | |
f6ce93d6 | 127 | |
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128 | // Return section flags. |
129 | uint64_t | |
130 | do_section_flags(unsigned int shndx) | |
131 | { return this->elf_file_.section_flags(shndx); } | |
132 | ||
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133 | private: |
134 | // For convenience. | |
135 | typedef Sized_dynobj<size, big_endian> This; | |
136 | static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size; | |
137 | static const int sym_size = elfcpp::Elf_sizes<size>::sym_size; | |
138 | static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size; | |
139 | typedef elfcpp::Shdr<size, big_endian> Shdr; | |
140 | typedef elfcpp::Dyn<size, big_endian> Dyn; | |
141 | ||
142 | // Find the dynamic symbol table and the version sections, given the | |
143 | // section headers. | |
144 | void | |
145 | find_dynsym_sections(const unsigned char* pshdrs, | |
146 | unsigned int* pdynshm_shndx, | |
147 | unsigned int* pversym_shndx, | |
148 | unsigned int* pverdef_shndx, | |
149 | unsigned int* pverneed_shndx, | |
150 | unsigned int* pdynamic_shndx); | |
151 | ||
152 | // Read the dynamic symbol section SHNDX. | |
153 | void | |
154 | read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx, | |
155 | elfcpp::SHT type, unsigned int link, | |
156 | File_view** view, off_t* view_size, | |
157 | unsigned int* view_info); | |
158 | ||
159 | // Set the SONAME from the SHT_DYNAMIC section at DYNAMIC_SHNDX. | |
160 | // The STRTAB parameters may have the relevant string table. | |
161 | void | |
162 | set_soname(const unsigned char* pshdrs, unsigned int dynamic_shndx, | |
163 | unsigned int strtab_shndx, const unsigned char* strtabu, | |
164 | off_t strtab_size); | |
165 | ||
166 | // Mapping from version number to version name. | |
167 | typedef std::vector<const char*> Version_map; | |
168 | ||
169 | // Create the version map. | |
170 | void | |
171 | make_version_map(Read_symbols_data* sd, Version_map*) const; | |
172 | ||
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173 | // Add version definitions to the version map. |
174 | void | |
175 | make_verdef_map(Read_symbols_data* sd, Version_map*) const; | |
176 | ||
177 | // Add version references to the version map. | |
178 | void | |
179 | make_verneed_map(Read_symbols_data* sd, Version_map*) const; | |
180 | ||
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181 | // Add an entry to the version map. |
182 | void | |
183 | set_version_map(Version_map*, unsigned int ndx, const char* name) const; | |
184 | ||
185 | // General access to the ELF file. | |
186 | elfcpp::Elf_file<size, big_endian, Object> elf_file_; | |
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187 | }; |
188 | ||
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189 | // A base class for Verdef and Verneed_version which just handles the |
190 | // version index which will be stored in the SHT_GNU_versym section. | |
191 | ||
192 | class Version_base | |
193 | { | |
194 | public: | |
195 | Version_base() | |
196 | : index_(-1U) | |
197 | { } | |
198 | ||
199 | virtual | |
200 | ~Version_base() | |
201 | { } | |
202 | ||
203 | // Return the version index. | |
204 | unsigned int | |
205 | index() const | |
206 | { | |
207 | gold_assert(this->index_ != -1U); | |
208 | return this->index_; | |
209 | } | |
210 | ||
211 | // Set the version index. | |
212 | void | |
213 | set_index(unsigned int index) | |
214 | { | |
215 | gold_assert(this->index_ == -1U); | |
216 | this->index_ = index; | |
217 | } | |
218 | ||
219 | // Clear the weak flag in a version definition. | |
220 | virtual void | |
221 | clear_weak() = 0; | |
222 | ||
223 | private: | |
224 | Version_base(const Version_base&); | |
225 | Version_base& operator=(const Version_base&); | |
226 | ||
227 | // The index of the version definition or reference. | |
228 | unsigned int index_; | |
229 | }; | |
230 | ||
231 | // This class handles a version being defined in the file we are | |
232 | // generating. | |
233 | ||
234 | class Verdef : public Version_base | |
235 | { | |
236 | public: | |
237 | Verdef(const char* name, bool is_base, bool is_weak, bool is_symbol_created) | |
238 | : name_(name), deps_(), is_base_(is_base), is_weak_(is_weak), | |
239 | is_symbol_created_(is_symbol_created) | |
240 | { } | |
241 | ||
242 | // Return the version name. | |
243 | const char* | |
244 | name() const | |
245 | { return this->name_; } | |
246 | ||
247 | // Return the number of dependencies. | |
248 | unsigned int | |
249 | count_dependencies() const | |
250 | { return this->deps_.size(); } | |
251 | ||
252 | // Add a dependency to this version. The NAME should be | |
253 | // canonicalized in the dynamic Stringpool. | |
254 | void | |
255 | add_dependency(const char* name) | |
256 | { this->deps_.push_back(name); } | |
257 | ||
258 | // Return whether this definition is weak. | |
259 | bool | |
260 | is_weak() const | |
261 | { return this->is_weak_; } | |
262 | ||
263 | // Clear the weak flag. | |
264 | void | |
265 | clear_weak() | |
266 | { this->is_weak_ = false; } | |
267 | ||
268 | // Return whether a version symbol has been created for this | |
269 | // definition. | |
270 | bool | |
271 | is_symbol_created() const | |
272 | { return this->is_symbol_created_; } | |
273 | ||
274 | // Write contents to buffer. | |
275 | template<int size, bool big_endian> | |
276 | unsigned char* | |
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277 | write(const Stringpool*, bool is_last, unsigned char* |
278 | ACCEPT_SIZE_ENDIAN) const; | |
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279 | |
280 | private: | |
281 | Verdef(const Verdef&); | |
282 | Verdef& operator=(const Verdef&); | |
283 | ||
284 | // The type of the list of version dependencies. Each dependency | |
285 | // should be canonicalized in the dynamic Stringpool. | |
286 | typedef std::vector<const char*> Deps; | |
287 | ||
288 | // The name of this version. This should be canonicalized in the | |
289 | // dynamic Stringpool. | |
290 | const char* name_; | |
291 | // A list of other versions which this version depends upon. | |
292 | Deps deps_; | |
293 | // Whether this is the base version. | |
294 | bool is_base_; | |
295 | // Whether this version is weak. | |
296 | bool is_weak_; | |
297 | // Whether a version symbol has been created. | |
298 | bool is_symbol_created_; | |
299 | }; | |
300 | ||
301 | // A referened version. This will be associated with a filename by | |
302 | // Verneed. | |
303 | ||
304 | class Verneed_version : public Version_base | |
305 | { | |
306 | public: | |
307 | Verneed_version(const char* version) | |
308 | : version_(version) | |
309 | { } | |
310 | ||
311 | // Return the version name. | |
312 | const char* | |
313 | version() const | |
314 | { return this->version_; } | |
315 | ||
316 | // Clear the weak flag. This is invalid for a reference. | |
317 | void | |
318 | clear_weak() | |
319 | { gold_unreachable(); } | |
320 | ||
321 | private: | |
322 | Verneed_version(const Verneed_version&); | |
323 | Verneed_version& operator=(const Verneed_version&); | |
324 | ||
325 | const char* version_; | |
326 | }; | |
327 | ||
328 | // Version references in a single dynamic object. | |
329 | ||
330 | class Verneed | |
331 | { | |
332 | public: | |
333 | Verneed(const char* filename) | |
334 | : filename_(filename), need_versions_() | |
335 | { } | |
336 | ||
337 | ~Verneed(); | |
338 | ||
339 | // Return the file name. | |
340 | const char* | |
341 | filename() const | |
342 | { return this->filename_; } | |
343 | ||
344 | // Return the number of versions. | |
345 | unsigned int | |
346 | count_versions() const | |
347 | { return this->need_versions_.size(); } | |
348 | ||
349 | // Add a version name. The name should be canonicalized in the | |
350 | // dynamic Stringpool. If the name is already present, this does | |
351 | // nothing. | |
352 | Verneed_version* | |
353 | add_name(const char* name); | |
354 | ||
355 | // Set the version indexes, starting at INDEX. Return the updated | |
356 | // INDEX. | |
357 | unsigned int | |
358 | finalize(unsigned int index); | |
359 | ||
360 | // Write contents to buffer. | |
361 | template<int size, bool big_endian> | |
362 | unsigned char* | |
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363 | write(const Stringpool*, bool is_last, unsigned char* |
364 | ACCEPT_SIZE_ENDIAN) const; | |
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365 | |
366 | private: | |
367 | Verneed(const Verneed&); | |
368 | Verneed& operator=(const Verneed&); | |
369 | ||
370 | // The type of the list of version names. Each name should be | |
371 | // canonicalized in the dynamic Stringpool. | |
372 | typedef std::vector<Verneed_version*> Need_versions; | |
373 | ||
374 | // The filename of the dynamic object. This should be | |
375 | // canonicalized in the dynamic Stringpool. | |
376 | const char* filename_; | |
377 | // The list of version names. | |
378 | Need_versions need_versions_; | |
379 | }; | |
380 | ||
381 | // This class handles version definitions and references which go into | |
382 | // the output file. | |
383 | ||
384 | class Versions | |
385 | { | |
386 | public: | |
387 | Versions() | |
388 | : defs_(), needs_(), version_table_(), is_finalized_(false) | |
389 | { } | |
390 | ||
391 | ~Versions(); | |
392 | ||
393 | // SYM is going into the dynamic symbol table and has a version. | |
394 | // Record the appropriate version information. | |
395 | void | |
396 | record_version(const General_options*, Stringpool*, const Symbol* sym); | |
397 | ||
398 | // Set the version indexes. DYNSYM_INDEX is the index we should use | |
399 | // for the next dynamic symbol. We add new dynamic symbols to SYMS | |
400 | // and return an updated DYNSYM_INDEX. | |
401 | unsigned int | |
402 | finalize(const Target*, Symbol_table* symtab, unsigned int dynsym_index, | |
403 | std::vector<Symbol*>* syms); | |
404 | ||
405 | // Return whether there are any version definitions. | |
406 | bool | |
407 | any_defs() const | |
408 | { return !this->defs_.empty(); } | |
409 | ||
410 | // Return whether there are any version references. | |
411 | bool | |
412 | any_needs() const | |
413 | { return !this->needs_.empty(); } | |
414 | ||
415 | // Build an allocated buffer holding the contents of the symbol | |
416 | // version section (.gnu.version). | |
417 | template<int size, bool big_endian> | |
418 | void | |
419 | symbol_section_contents(const Stringpool*, unsigned int local_symcount, | |
420 | const std::vector<Symbol*>& syms, | |
91da9340 ILT |
421 | unsigned char**, unsigned int* |
422 | ACCEPT_SIZE_ENDIAN) const; | |
14b31740 ILT |
423 | |
424 | // Build an allocated buffer holding the contents of the version | |
425 | // definition section (.gnu.version_d). | |
426 | template<int size, bool big_endian> | |
427 | void | |
428 | def_section_contents(const Stringpool*, unsigned char**, | |
91da9340 ILT |
429 | unsigned int* psize, unsigned int* pentries |
430 | ACCEPT_SIZE_ENDIAN) const; | |
14b31740 ILT |
431 | |
432 | // Build an allocated buffer holding the contents of the version | |
433 | // reference section (.gnu.version_r). | |
434 | template<int size, bool big_endian> | |
435 | void | |
436 | need_section_contents(const Stringpool*, unsigned char**, | |
91da9340 ILT |
437 | unsigned int* psize, unsigned int* pentries |
438 | ACCEPT_SIZE_ENDIAN) const; | |
14b31740 ILT |
439 | |
440 | private: | |
441 | // The type of the list of version definitions. | |
442 | typedef std::vector<Verdef*> Defs; | |
443 | ||
444 | // The type of the list of version references. | |
445 | typedef std::vector<Verneed*> Needs; | |
446 | ||
447 | // Handle a symbol SYM defined with version VERSION. | |
448 | void | |
449 | add_def(const General_options*, const Symbol* sym, const char* version, | |
450 | Stringpool::Key); | |
451 | ||
452 | // Add a reference to version NAME in file FILENAME. | |
453 | void | |
454 | add_need(Stringpool*, const char* filename, const char* name, | |
455 | Stringpool::Key); | |
456 | ||
457 | // Return the version index to use for SYM. | |
458 | unsigned int | |
459 | version_index(const Stringpool*, const Symbol* sym) const; | |
460 | ||
461 | // We keep a hash table mapping canonicalized name/version pairs to | |
462 | // a version base. | |
463 | typedef std::pair<Stringpool::Key, Stringpool::Key> Key; | |
464 | ||
465 | struct Version_table_hash | |
466 | { | |
467 | size_t | |
468 | operator()(const Key& k) const | |
469 | { return k.first + k.second; } | |
470 | }; | |
471 | ||
472 | struct Version_table_eq | |
473 | { | |
474 | bool | |
475 | operator()(const Key& k1, const Key& k2) const | |
476 | { return k1.first == k2.first && k1.second == k2.second; } | |
477 | }; | |
478 | ||
479 | typedef Unordered_map<Key, Version_base*, Version_table_hash, | |
480 | Version_table_eq> Version_table; | |
481 | ||
482 | // The version definitions. | |
483 | Defs defs_; | |
484 | // The version references. | |
485 | Needs needs_; | |
486 | // The mapping from a canonicalized version/filename pair to a | |
487 | // version index. The filename may be NULL. | |
488 | Version_table version_table_; | |
489 | // Whether the version indexes have been set. | |
490 | bool is_finalized_; | |
491 | }; | |
492 | ||
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493 | } // End namespace gold. |
494 | ||
495 | #endif // !defined(GOLD_DYNOBJ_H) |