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1 // dynobj.h -- dynamic object support for gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
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.
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.
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.
23 #ifndef GOLD_DYNOBJ_H
24 #define GOLD_DYNOBJ_H
26 #include <vector>
28 #include "stringpool.h"
29 #include "object.h"
31 namespace gold
34 class Version_script_info;
36 // A dynamic object (ET_DYN). This is an abstract base class itself.
37 // The implementations is the template class Sized_dynobj.
39 class Dynobj : public Object
41 public:
42 // We keep a list of all the DT_NEEDED entries we find.
43 typedef std::vector<std::string> Needed;
45 Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0);
47 // Return the name to use in a DT_NEEDED entry for this object.
48 const char*
49 soname() const
50 { return this->soname_.c_str(); }
52 // Return the list of DT_NEEDED strings.
53 const Needed&
54 needed() const
55 { return this->needed_; }
57 // Return whether this dynamic object has any DT_NEEDED entries
58 // which were not seen during the link.
59 bool
60 has_unknown_needed_entries() const
62 gold_assert(this->unknown_needed_ != UNKNOWN_NEEDED_UNSET);
63 return this->unknown_needed_ == UNKNOWN_NEEDED_TRUE;
66 // Set whether this dynamic object has any DT_NEEDED entries which
67 // were not seen during the link.
68 void
69 set_has_unknown_needed_entries(bool set)
71 gold_assert(this->unknown_needed_ == UNKNOWN_NEEDED_UNSET);
72 this->unknown_needed_ = set ? UNKNOWN_NEEDED_TRUE : UNKNOWN_NEEDED_FALSE;
75 // Compute the ELF hash code for a string.
76 static uint32_t
77 elf_hash(const char*);
79 // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
80 // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the
81 // number of local dynamic symbols, which is the index of the first
82 // dynamic gobal symbol.
83 static void
84 create_elf_hash_table(const std::vector<Symbol*>& dynsyms,
85 unsigned int local_dynsym_count,
86 unsigned char** pphash,
87 unsigned int* phashlen);
89 // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS
90 // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number
91 // of local dynamic symbols, which is the index of the first dynamic
92 // gobal symbol.
93 static void
94 create_gnu_hash_table(const std::vector<Symbol*>& dynsyms,
95 unsigned int local_dynsym_count,
96 unsigned char** pphash, unsigned int* phashlen);
98 protected:
99 // Set the DT_SONAME string.
100 void
101 set_soname_string(const char* s)
102 { this->soname_.assign(s); }
104 // Add an entry to the list of DT_NEEDED strings.
105 void
106 add_needed(const char* s)
107 { this->needed_.push_back(std::string(s)); }
109 private:
110 // Compute the GNU hash code for a string.
111 static uint32_t
112 gnu_hash(const char*);
114 // Compute the number of hash buckets to use.
115 static unsigned int
116 compute_bucket_count(const std::vector<uint32_t>& hashcodes,
117 bool for_gnu_hash_table);
119 // Sized version of create_elf_hash_table.
120 template<bool big_endian>
121 static void
122 sized_create_elf_hash_table(const std::vector<uint32_t>& bucket,
123 const std::vector<uint32_t>& chain,
124 unsigned char* phash,
125 unsigned int hashlen);
127 // Sized version of create_gnu_hash_table.
128 template<int size, bool big_endian>
129 static void
130 sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms,
131 const std::vector<uint32_t>& dynsym_hashvals,
132 unsigned int unhashed_dynsym_count,
133 unsigned char** pphash,
134 unsigned int* phashlen);
136 // Values for the has_unknown_needed_entries_ field.
137 enum Unknown_needed
139 UNKNOWN_NEEDED_UNSET,
140 UNKNOWN_NEEDED_TRUE,
141 UNKNOWN_NEEDED_FALSE
144 // The DT_SONAME name, if any.
145 std::string soname_;
146 // The list of DT_NEEDED entries.
147 Needed needed_;
148 // Whether this dynamic object has any DT_NEEDED entries not seen
149 // during the link.
150 Unknown_needed unknown_needed_;
153 // A dynamic object, size and endian specific version.
155 template<int size, bool big_endian>
156 class Sized_dynobj : public Dynobj
158 public:
159 typedef typename Sized_relobj<size, big_endian>::Symbols Symbols;
161 Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset,
162 const typename elfcpp::Ehdr<size, big_endian>&);
164 // Set up the object file based on TARGET.
165 void
166 setup();
168 // Read the symbols.
169 void
170 do_read_symbols(Read_symbols_data*);
172 // Lay out the input sections.
173 void
174 do_layout(Symbol_table*, Layout*, Read_symbols_data*);
176 // Add the symbols to the symbol table.
177 void
178 do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
180 Archive::Should_include
181 do_should_include_member(Symbol_table* symtab, Read_symbols_data*,
182 std::string* why);
184 // Get the size of a section.
185 uint64_t
186 do_section_size(unsigned int shndx)
187 { return this->elf_file_.section_size(shndx); }
189 // Get the name of a section.
190 std::string
191 do_section_name(unsigned int shndx)
192 { return this->elf_file_.section_name(shndx); }
194 // Return a view of the contents of a section. Set *PLEN to the
195 // size.
196 Object::Location
197 do_section_contents(unsigned int shndx)
198 { return this->elf_file_.section_contents(shndx); }
200 // Return section flags.
201 uint64_t
202 do_section_flags(unsigned int shndx)
203 { return this->elf_file_.section_flags(shndx); }
205 // Not used for dynobj.
206 uint64_t
207 do_section_entsize(unsigned int )
208 { gold_unreachable(); }
210 // Return section address.
211 uint64_t
212 do_section_address(unsigned int shndx)
213 { return this->elf_file_.section_addr(shndx); }
215 // Return section type.
216 unsigned int
217 do_section_type(unsigned int shndx)
218 { return this->elf_file_.section_type(shndx); }
220 // Return the section link field.
221 unsigned int
222 do_section_link(unsigned int shndx)
223 { return this->elf_file_.section_link(shndx); }
225 // Return the section link field.
226 unsigned int
227 do_section_info(unsigned int shndx)
228 { return this->elf_file_.section_info(shndx); }
230 // Return the section alignment.
231 uint64_t
232 do_section_addralign(unsigned int shndx)
233 { return this->elf_file_.section_addralign(shndx); }
235 // Return the Xindex structure to use.
236 Xindex*
237 do_initialize_xindex();
239 // Get symbol counts.
240 void
241 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
243 // Get the global symbols.
244 const Symbols*
245 do_get_global_symbols() const
246 { return this->symbols_; }
248 private:
249 // For convenience.
250 typedef Sized_dynobj<size, big_endian> This;
251 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
252 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
253 static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
254 typedef elfcpp::Shdr<size, big_endian> Shdr;
255 typedef elfcpp::Dyn<size, big_endian> Dyn;
257 // Adjust a section index if necessary.
258 unsigned int
259 adjust_shndx(unsigned int shndx)
261 if (shndx >= elfcpp::SHN_LORESERVE)
262 shndx += this->elf_file_.large_shndx_offset();
263 return shndx;
266 // Find the dynamic symbol table and the version sections, given the
267 // section headers.
268 void
269 find_dynsym_sections(const unsigned char* pshdrs,
270 unsigned int* pversym_shndx,
271 unsigned int* pverdef_shndx,
272 unsigned int* pverneed_shndx,
273 unsigned int* pdynamic_shndx);
275 // Read the dynamic symbol section SHNDX.
276 void
277 read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
278 elfcpp::SHT type, unsigned int link,
279 File_view** view, section_size_type* view_size,
280 unsigned int* view_info);
282 // Read the dynamic tags.
283 void
284 read_dynamic(const unsigned char* pshdrs, unsigned int dynamic_shndx,
285 unsigned int strtab_shndx, const unsigned char* strtabu,
286 off_t strtab_size);
288 // Mapping from version number to version name.
289 typedef std::vector<const char*> Version_map;
291 // Create the version map.
292 void
293 make_version_map(Read_symbols_data* sd, Version_map*) const;
295 // Add version definitions to the version map.
296 void
297 make_verdef_map(Read_symbols_data* sd, Version_map*) const;
299 // Add version references to the version map.
300 void
301 make_verneed_map(Read_symbols_data* sd, Version_map*) const;
303 // Add an entry to the version map.
304 void
305 set_version_map(Version_map*, unsigned int ndx, const char* name) const;
307 // General access to the ELF file.
308 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
309 // The section index of the dynamic symbol table.
310 unsigned int dynsym_shndx_;
311 // The entries in the symbol table for the symbols. We only keep
312 // this if we need it to print symbol information.
313 Symbols* symbols_;
314 // Number of defined symbols.
315 size_t defined_count_;
318 // A base class for Verdef and Verneed_version which just handles the
319 // version index which will be stored in the SHT_GNU_versym section.
321 class Version_base
323 public:
324 Version_base()
325 : index_(-1U)
328 virtual
329 ~Version_base()
332 // Return the version index.
333 unsigned int
334 index() const
336 gold_assert(this->index_ != -1U);
337 return this->index_;
340 // Set the version index.
341 void
342 set_index(unsigned int index)
344 gold_assert(this->index_ == -1U);
345 this->index_ = index;
348 // Clear the weak flag in a version definition.
349 virtual void
350 clear_weak() = 0;
352 private:
353 Version_base(const Version_base&);
354 Version_base& operator=(const Version_base&);
356 // The index of the version definition or reference.
357 unsigned int index_;
360 // This class handles a version being defined in the file we are
361 // generating.
363 class Verdef : public Version_base
365 public:
366 Verdef(const char* name, const std::vector<std::string>& deps,
367 bool is_base, bool is_weak, bool is_info, bool is_symbol_created)
368 : name_(name), deps_(deps), is_base_(is_base), is_weak_(is_weak),
369 is_info_(is_info), is_symbol_created_(is_symbol_created)
372 // Return the version name.
373 const char*
374 name() const
375 { return this->name_; }
377 // Return the number of dependencies.
378 unsigned int
379 count_dependencies() const
380 { return this->deps_.size(); }
382 // Add a dependency to this version. The NAME should be
383 // canonicalized in the dynamic Stringpool.
384 void
385 add_dependency(const char* name)
386 { this->deps_.push_back(name); }
388 // Return whether this definition is weak.
389 bool
390 is_weak() const
391 { return this->is_weak_; }
393 // Clear the weak flag.
394 void
395 clear_weak()
396 { this->is_weak_ = false; }
398 // Return whether this definition is informational.
399 bool
400 is_info() const
401 { return this->is_info_; }
403 // Return whether a version symbol has been created for this
404 // definition.
405 bool
406 is_symbol_created() const
407 { return this->is_symbol_created_; }
409 // Write contents to buffer.
410 template<int size, bool big_endian>
411 unsigned char*
412 write(const Stringpool*, bool is_last, unsigned char*) const;
414 private:
415 Verdef(const Verdef&);
416 Verdef& operator=(const Verdef&);
418 // The type of the list of version dependencies. Each dependency
419 // should be canonicalized in the dynamic Stringpool.
420 typedef std::vector<std::string> Deps;
422 // The name of this version. This should be canonicalized in the
423 // dynamic Stringpool.
424 const char* name_;
425 // A list of other versions which this version depends upon.
426 Deps deps_;
427 // Whether this is the base version.
428 bool is_base_;
429 // Whether this version is weak.
430 bool is_weak_;
431 // Whether this version is informational.
432 bool is_info_;
433 // Whether a version symbol has been created.
434 bool is_symbol_created_;
437 // A referened version. This will be associated with a filename by
438 // Verneed.
440 class Verneed_version : public Version_base
442 public:
443 Verneed_version(const char* version)
444 : version_(version)
447 // Return the version name.
448 const char*
449 version() const
450 { return this->version_; }
452 // Clear the weak flag. This is invalid for a reference.
453 void
454 clear_weak()
455 { gold_unreachable(); }
457 private:
458 Verneed_version(const Verneed_version&);
459 Verneed_version& operator=(const Verneed_version&);
461 const char* version_;
464 // Version references in a single dynamic object.
466 class Verneed
468 public:
469 Verneed(const char* filename)
470 : filename_(filename), need_versions_()
473 ~Verneed();
475 // Return the file name.
476 const char*
477 filename() const
478 { return this->filename_; }
480 // Return the number of versions.
481 unsigned int
482 count_versions() const
483 { return this->need_versions_.size(); }
485 // Add a version name. The name should be canonicalized in the
486 // dynamic Stringpool. If the name is already present, this does
487 // nothing.
488 Verneed_version*
489 add_name(const char* name);
491 // Set the version indexes, starting at INDEX. Return the updated
492 // INDEX.
493 unsigned int
494 finalize(unsigned int index);
496 // Write contents to buffer.
497 template<int size, bool big_endian>
498 unsigned char*
499 write(const Stringpool*, bool is_last, unsigned char*) const;
501 private:
502 Verneed(const Verneed&);
503 Verneed& operator=(const Verneed&);
505 // The type of the list of version names. Each name should be
506 // canonicalized in the dynamic Stringpool.
507 typedef std::vector<Verneed_version*> Need_versions;
509 // The filename of the dynamic object. This should be
510 // canonicalized in the dynamic Stringpool.
511 const char* filename_;
512 // The list of version names.
513 Need_versions need_versions_;
516 // This class handles version definitions and references which go into
517 // the output file.
519 class Versions
521 public:
522 Versions(const Version_script_info&, Stringpool*);
524 ~Versions();
526 // SYM is going into the dynamic symbol table and has a version.
527 // Record the appropriate version information.
528 void
529 record_version(const Symbol_table* symtab, Stringpool*, const Symbol* sym);
531 // Set the version indexes. DYNSYM_INDEX is the index we should use
532 // for the next dynamic symbol. We add new dynamic symbols to SYMS
533 // and return an updated DYNSYM_INDEX.
534 unsigned int
535 finalize(Symbol_table* symtab, unsigned int dynsym_index,
536 std::vector<Symbol*>* syms);
538 // Return whether there are any version definitions.
539 bool
540 any_defs() const
541 { return !this->defs_.empty(); }
543 // Return whether there are any version references.
544 bool
545 any_needs() const
546 { return !this->needs_.empty(); }
548 // Build an allocated buffer holding the contents of the symbol
549 // version section (.gnu.version).
550 template<int size, bool big_endian>
551 void
552 symbol_section_contents(const Symbol_table*, const Stringpool*,
553 unsigned int local_symcount,
554 const std::vector<Symbol*>& syms,
555 unsigned char**, unsigned int*) const;
557 // Build an allocated buffer holding the contents of the version
558 // definition section (.gnu.version_d).
559 template<int size, bool big_endian>
560 void
561 def_section_contents(const Stringpool*, unsigned char**,
562 unsigned int* psize, unsigned int* pentries) const;
564 // Build an allocated buffer holding the contents of the version
565 // reference section (.gnu.version_r).
566 template<int size, bool big_endian>
567 void
568 need_section_contents(const Stringpool*, unsigned char**,
569 unsigned int* psize, unsigned int* pentries) const;
571 const Version_script_info&
572 version_script() const
573 { return this->version_script_; }
575 private:
576 Versions(const Versions&);
577 Versions& operator=(const Versions&);
579 // The type of the list of version definitions.
580 typedef std::vector<Verdef*> Defs;
582 // The type of the list of version references.
583 typedef std::vector<Verneed*> Needs;
585 // Handle a symbol SYM defined with version VERSION.
586 void
587 add_def(const Symbol* sym, const char* version, Stringpool::Key);
589 // Add a reference to version NAME in file FILENAME.
590 void
591 add_need(Stringpool*, const char* filename, const char* name,
592 Stringpool::Key);
594 // Get the dynamic object to use for SYM.
595 Dynobj*
596 get_dynobj_for_sym(const Symbol_table*, const Symbol* sym) const;
598 // Return the version index to use for SYM.
599 unsigned int
600 version_index(const Symbol_table*, const Stringpool*,
601 const Symbol* sym) const;
603 // Define the base version of a shared library.
604 void
605 define_base_version(Stringpool* dynpool);
607 // We keep a hash table mapping canonicalized name/version pairs to
608 // a version base.
609 typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
611 struct Version_table_hash
613 size_t
614 operator()(const Key& k) const
615 { return k.first + k.second; }
618 struct Version_table_eq
620 bool
621 operator()(const Key& k1, const Key& k2) const
622 { return k1.first == k2.first && k1.second == k2.second; }
625 typedef Unordered_map<Key, Version_base*, Version_table_hash,
626 Version_table_eq> Version_table;
628 // The version definitions.
629 Defs defs_;
630 // The version references.
631 Needs needs_;
632 // The mapping from a canonicalized version/filename pair to a
633 // version index. The filename may be NULL.
634 Version_table version_table_;
635 // Whether the version indexes have been set.
636 bool is_finalized_;
637 // Contents of --version-script, if passed, or NULL.
638 const Version_script_info& version_script_;
639 // Whether we need to insert a base version. This is only used for
640 // shared libaries and is cleared when the base version is defined.
641 bool needs_base_version_;
644 } // End namespace gold.
646 #endif // !defined(GOLD_DYNOBJ_H)