1 // dynobj.h -- dynamic object support for gold -*- C++ -*-
3 // Copyright 2006, 2007, 2008 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.
28 #include "stringpool.h"
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
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.
50 { return this->soname_.c_str(); }
52 // Return the list of DT_NEEDED strings.
55 { return this->needed_; }
57 // Return whether this dynamic object has any DT_NEEDED entries
58 // which were not seen during the link.
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.
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.
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.
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
94 create_gnu_hash_table(const std::vector<Symbol*>& dynsyms,
95 unsigned int local_dynsym_count,
96 unsigned char** pphash, unsigned int* phashlen);
99 // Set the DT_SONAME string.
101 set_soname_string(const char* s)
102 { this->soname_.assign(s); }
104 // Add an entry to the list of DT_NEEDED strings.
106 add_needed(const char* s)
107 { this->needed_.push_back(std::string(s)); }
110 // Compute the GNU hash code for a string.
112 gnu_hash(const char*);
114 // Compute the number of hash buckets to use.
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>
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>
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.
139 UNKNOWN_NEEDED_UNSET,
144 // The DT_SONAME name, if any.
146 // The list of DT_NEEDED entries.
148 // Whether this dynamic object has any DT_NEEDED entries not seen
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
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 the ELF header.
166 setup(const typename elfcpp::Ehdr<size, big_endian>&);
170 do_read_symbols(Read_symbols_data*);
172 // Lay out the input sections.
174 do_layout(Symbol_table*, Layout*, Read_symbols_data*);
176 // Add the symbols to the symbol table.
178 do_add_symbols(Symbol_table*, Read_symbols_data*, Layout*);
180 // Get the size of a section.
182 do_section_size(unsigned int shndx)
183 { return this->elf_file_.section_size(shndx); }
185 // Get the name of a section.
187 do_section_name(unsigned int shndx)
188 { return this->elf_file_.section_name(shndx); }
190 // Return a view of the contents of a section. Set *PLEN to the
193 do_section_contents(unsigned int shndx)
194 { return this->elf_file_.section_contents(shndx); }
196 // Return section flags.
198 do_section_flags(unsigned int shndx)
199 { return this->elf_file_.section_flags(shndx); }
201 // Return section address.
203 do_section_address(unsigned int shndx)
204 { return this->elf_file_.section_addr(shndx); }
206 // Return section type.
208 do_section_type(unsigned int shndx)
209 { return this->elf_file_.section_type(shndx); }
211 // Return the section link field.
213 do_section_link(unsigned int shndx)
214 { return this->elf_file_.section_link(shndx); }
216 // Return the section link field.
218 do_section_info(unsigned int shndx)
219 { return this->elf_file_.section_info(shndx); }
221 // Return the section alignment.
223 do_section_addralign(unsigned int shndx)
224 { return this->elf_file_.section_addralign(shndx); }
226 // Return the Xindex structure to use.
228 do_initialize_xindex();
230 // Get symbol counts.
232 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
236 typedef Sized_dynobj<size, big_endian> This;
237 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
238 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
239 static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
240 typedef elfcpp::Shdr<size, big_endian> Shdr;
241 typedef elfcpp::Dyn<size, big_endian> Dyn;
243 // Adjust a section index if necessary.
245 adjust_shndx(unsigned int shndx)
247 if (shndx >= elfcpp::SHN_LORESERVE)
248 shndx += this->elf_file_.large_shndx_offset();
252 // Find the dynamic symbol table and the version sections, given the
255 find_dynsym_sections(const unsigned char* pshdrs,
256 unsigned int* pversym_shndx,
257 unsigned int* pverdef_shndx,
258 unsigned int* pverneed_shndx,
259 unsigned int* pdynamic_shndx);
261 // Read the dynamic symbol section SHNDX.
263 read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
264 elfcpp::SHT type, unsigned int link,
265 File_view** view, section_size_type* view_size,
266 unsigned int* view_info);
268 // Read the dynamic tags.
270 read_dynamic(const unsigned char* pshdrs, unsigned int dynamic_shndx,
271 unsigned int strtab_shndx, const unsigned char* strtabu,
274 // Mapping from version number to version name.
275 typedef std::vector<const char*> Version_map;
277 // Create the version map.
279 make_version_map(Read_symbols_data* sd, Version_map*) const;
281 // Add version definitions to the version map.
283 make_verdef_map(Read_symbols_data* sd, Version_map*) const;
285 // Add version references to the version map.
287 make_verneed_map(Read_symbols_data* sd, Version_map*) const;
289 // Add an entry to the version map.
291 set_version_map(Version_map*, unsigned int ndx, const char* name) const;
293 // General access to the ELF file.
294 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
295 // The section index of the dynamic symbol table.
296 unsigned int dynsym_shndx_;
297 // The entries in the symbol table for the symbols. We only keep
298 // this if we need it to print symbol information.
300 // Number of defined symbols.
301 size_t defined_count_;
304 // A base class for Verdef and Verneed_version which just handles the
305 // version index which will be stored in the SHT_GNU_versym section.
318 // Return the version index.
322 gold_assert(this->index_ != -1U);
326 // Set the version index.
328 set_index(unsigned int index)
330 gold_assert(this->index_ == -1U);
331 this->index_ = index;
334 // Clear the weak flag in a version definition.
339 Version_base(const Version_base&);
340 Version_base& operator=(const Version_base&);
342 // The index of the version definition or reference.
346 // This class handles a version being defined in the file we are
349 class Verdef : public Version_base
352 Verdef(const char* name, const std::vector<std::string>& deps,
353 bool is_base, bool is_weak, bool is_symbol_created)
354 : name_(name), deps_(deps), is_base_(is_base), is_weak_(is_weak),
355 is_symbol_created_(is_symbol_created)
358 // Return the version name.
361 { return this->name_; }
363 // Return the number of dependencies.
365 count_dependencies() const
366 { return this->deps_.size(); }
368 // Add a dependency to this version. The NAME should be
369 // canonicalized in the dynamic Stringpool.
371 add_dependency(const char* name)
372 { this->deps_.push_back(name); }
374 // Return whether this definition is weak.
377 { return this->is_weak_; }
379 // Clear the weak flag.
382 { this->is_weak_ = false; }
384 // Return whether a version symbol has been created for this
387 is_symbol_created() const
388 { return this->is_symbol_created_; }
390 // Write contents to buffer.
391 template<int size, bool big_endian>
393 write(const Stringpool*, bool is_last, unsigned char*) const;
396 Verdef(const Verdef&);
397 Verdef& operator=(const Verdef&);
399 // The type of the list of version dependencies. Each dependency
400 // should be canonicalized in the dynamic Stringpool.
401 typedef std::vector<std::string> Deps;
403 // The name of this version. This should be canonicalized in the
404 // dynamic Stringpool.
406 // A list of other versions which this version depends upon.
408 // Whether this is the base version.
410 // Whether this version is weak.
412 // Whether a version symbol has been created.
413 bool is_symbol_created_;
416 // A referened version. This will be associated with a filename by
419 class Verneed_version : public Version_base
422 Verneed_version(const char* version)
426 // Return the version name.
429 { return this->version_; }
431 // Clear the weak flag. This is invalid for a reference.
434 { gold_unreachable(); }
437 Verneed_version(const Verneed_version&);
438 Verneed_version& operator=(const Verneed_version&);
440 const char* version_;
443 // Version references in a single dynamic object.
448 Verneed(const char* filename)
449 : filename_(filename), need_versions_()
454 // Return the file name.
457 { return this->filename_; }
459 // Return the number of versions.
461 count_versions() const
462 { return this->need_versions_.size(); }
464 // Add a version name. The name should be canonicalized in the
465 // dynamic Stringpool. If the name is already present, this does
468 add_name(const char* name);
470 // Set the version indexes, starting at INDEX. Return the updated
473 finalize(unsigned int index);
475 // Write contents to buffer.
476 template<int size, bool big_endian>
478 write(const Stringpool*, bool is_last, unsigned char*) const;
481 Verneed(const Verneed&);
482 Verneed& operator=(const Verneed&);
484 // The type of the list of version names. Each name should be
485 // canonicalized in the dynamic Stringpool.
486 typedef std::vector<Verneed_version*> Need_versions;
488 // The filename of the dynamic object. This should be
489 // canonicalized in the dynamic Stringpool.
490 const char* filename_;
491 // The list of version names.
492 Need_versions need_versions_;
495 // This class handles version definitions and references which go into
501 Versions(const Version_script_info&, Stringpool*);
505 // SYM is going into the dynamic symbol table and has a version.
506 // Record the appropriate version information.
508 record_version(const Symbol_table* symtab, Stringpool*, const Symbol* sym);
510 // Set the version indexes. DYNSYM_INDEX is the index we should use
511 // for the next dynamic symbol. We add new dynamic symbols to SYMS
512 // and return an updated DYNSYM_INDEX.
514 finalize(Symbol_table* symtab, unsigned int dynsym_index,
515 std::vector<Symbol*>* syms);
517 // Return whether there are any version definitions.
520 { return !this->defs_.empty(); }
522 // Return whether there are any version references.
525 { return !this->needs_.empty(); }
527 // Build an allocated buffer holding the contents of the symbol
528 // version section (.gnu.version).
529 template<int size, bool big_endian>
531 symbol_section_contents(const Symbol_table*, const Stringpool*,
532 unsigned int local_symcount,
533 const std::vector<Symbol*>& syms,
534 unsigned char**, unsigned int*) const;
536 // Build an allocated buffer holding the contents of the version
537 // definition section (.gnu.version_d).
538 template<int size, bool big_endian>
540 def_section_contents(const Stringpool*, unsigned char**,
541 unsigned int* psize, unsigned int* pentries) const;
543 // Build an allocated buffer holding the contents of the version
544 // reference section (.gnu.version_r).
545 template<int size, bool big_endian>
547 need_section_contents(const Stringpool*, unsigned char**,
548 unsigned int* psize, unsigned int* pentries) const;
550 const Version_script_info&
551 version_script() const
552 { return this->version_script_; }
555 Versions(const Versions&);
556 Versions& operator=(const Versions&);
558 // The type of the list of version definitions.
559 typedef std::vector<Verdef*> Defs;
561 // The type of the list of version references.
562 typedef std::vector<Verneed*> Needs;
564 // Handle a symbol SYM defined with version VERSION.
566 add_def(const Symbol* sym, const char* version, Stringpool::Key);
568 // Add a reference to version NAME in file FILENAME.
570 add_need(Stringpool*, const char* filename, const char* name,
573 // Get the dynamic object to use for SYM.
575 get_dynobj_for_sym(const Symbol_table*, const Symbol* sym) const;
577 // Return the version index to use for SYM.
579 version_index(const Symbol_table*, const Stringpool*,
580 const Symbol* sym) const;
582 // We keep a hash table mapping canonicalized name/version pairs to
584 typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
586 struct Version_table_hash
589 operator()(const Key& k) const
590 { return k.first + k.second; }
593 struct Version_table_eq
596 operator()(const Key& k1, const Key& k2) const
597 { return k1.first == k2.first && k1.second == k2.second; }
600 typedef Unordered_map<Key, Version_base*, Version_table_hash,
601 Version_table_eq> Version_table;
603 // The version definitions.
605 // The version references.
607 // The mapping from a canonicalized version/filename pair to a
608 // version index. The filename may be NULL.
609 Version_table version_table_;
610 // Whether the version indexes have been set.
612 // Contents of --version-script, if passed, or NULL.
613 const Version_script_info& version_script_;
616 } // End namespace gold.
618 #endif // !defined(GOLD_DYNOBJ_H)