1 // dynobj.h -- dynamic object support for gold -*- C++ -*-
3 // Copyright 2006, 2007 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 General_options;
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 Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0);
44 // Return the name to use in a DT_NEEDED entry for this object.
48 // Compute the ELF hash code for a string.
50 elf_hash(const char*);
52 // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
53 // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the
54 // number of local dynamic symbols, which is the index of the first
55 // dynamic gobal symbol.
57 create_elf_hash_table(const std::vector<Symbol*>& dynsyms,
58 unsigned int local_dynsym_count,
59 unsigned char** pphash,
60 unsigned int* phashlen);
62 // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS
63 // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number
64 // of local dynamic symbols, which is the index of the first dynamic
67 create_gnu_hash_table(const std::vector<Symbol*>& dynsyms,
68 unsigned int local_dynsym_count,
69 unsigned char** pphash, unsigned int* phashlen);
72 // Set the DT_SONAME string.
74 set_soname_string(const char* s)
75 { this->soname_.assign(s); }
78 // Compute the GNU hash code for a string.
80 gnu_hash(const char*);
82 // Compute the number of hash buckets to use.
84 compute_bucket_count(const std::vector<uint32_t>& hashcodes,
85 bool for_gnu_hash_table);
87 // Sized version of create_elf_hash_table.
88 template<bool big_endian>
90 sized_create_elf_hash_table(const std::vector<uint32_t>& bucket,
91 const std::vector<uint32_t>& chain,
93 unsigned int hashlen);
95 // Sized version of create_gnu_hash_table.
96 template<int size, bool big_endian>
98 sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms,
99 const std::vector<uint32_t>& dynsym_hashvals,
100 unsigned int unhashed_dynsym_count,
101 unsigned char** pphash,
102 unsigned int* phashlen);
104 // The DT_SONAME name, if any.
108 // A dynamic object, size and endian specific version.
110 template<int size, bool big_endian>
111 class Sized_dynobj : public Dynobj
114 Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset,
115 const typename elfcpp::Ehdr<size, big_endian>&);
117 // Set up the object file based on the ELF header.
119 setup(const typename elfcpp::Ehdr<size, big_endian>&);
123 do_read_symbols(Read_symbols_data*);
125 // Lay out the input sections.
127 do_layout(Symbol_table*, Layout*, Read_symbols_data*);
129 // Add the symbols to the symbol table.
131 do_add_symbols(Symbol_table*, Read_symbols_data*);
133 // Get the name of a section.
135 do_section_name(unsigned int shndx)
136 { return this->elf_file_.section_name(shndx); }
138 // Return a view of the contents of a section. Set *PLEN to the
141 do_section_contents(unsigned int shndx)
142 { return this->elf_file_.section_contents(shndx); }
144 // Return section flags.
146 do_section_flags(unsigned int shndx)
147 { return this->elf_file_.section_flags(shndx); }
149 // Return the section link field.
151 do_section_link(unsigned int shndx)
152 { return this->elf_file_.section_link(shndx); }
156 typedef Sized_dynobj<size, big_endian> This;
157 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
158 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
159 static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
160 typedef elfcpp::Shdr<size, big_endian> Shdr;
161 typedef elfcpp::Dyn<size, big_endian> Dyn;
163 // Find the dynamic symbol table and the version sections, given the
166 find_dynsym_sections(const unsigned char* pshdrs,
167 unsigned int* pdynshm_shndx,
168 unsigned int* pversym_shndx,
169 unsigned int* pverdef_shndx,
170 unsigned int* pverneed_shndx,
171 unsigned int* pdynamic_shndx);
173 // Read the dynamic symbol section SHNDX.
175 read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
176 elfcpp::SHT type, unsigned int link,
177 File_view** view, off_t* view_size,
178 unsigned int* view_info);
180 // Set the SONAME from the SHT_DYNAMIC section at DYNAMIC_SHNDX.
181 // The STRTAB parameters may have the relevant string table.
183 set_soname(const unsigned char* pshdrs, unsigned int dynamic_shndx,
184 unsigned int strtab_shndx, const unsigned char* strtabu,
187 // Mapping from version number to version name.
188 typedef std::vector<const char*> Version_map;
190 // Create the version map.
192 make_version_map(Read_symbols_data* sd, Version_map*) const;
194 // Add version definitions to the version map.
196 make_verdef_map(Read_symbols_data* sd, Version_map*) const;
198 // Add version references to the version map.
200 make_verneed_map(Read_symbols_data* sd, Version_map*) const;
202 // Add an entry to the version map.
204 set_version_map(Version_map*, unsigned int ndx, const char* name) const;
206 // General access to the ELF file.
207 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
210 // A base class for Verdef and Verneed_version which just handles the
211 // version index which will be stored in the SHT_GNU_versym section.
224 // Return the version index.
228 gold_assert(this->index_ != -1U);
232 // Set the version index.
234 set_index(unsigned int index)
236 gold_assert(this->index_ == -1U);
237 this->index_ = index;
240 // Clear the weak flag in a version definition.
245 Version_base(const Version_base&);
246 Version_base& operator=(const Version_base&);
248 // The index of the version definition or reference.
252 // This class handles a version being defined in the file we are
255 class Verdef : public Version_base
258 Verdef(const char* name, bool is_base, bool is_weak, bool is_symbol_created)
259 : name_(name), deps_(), is_base_(is_base), is_weak_(is_weak),
260 is_symbol_created_(is_symbol_created)
263 // Return the version name.
266 { return this->name_; }
268 // Return the number of dependencies.
270 count_dependencies() const
271 { return this->deps_.size(); }
273 // Add a dependency to this version. The NAME should be
274 // canonicalized in the dynamic Stringpool.
276 add_dependency(const char* name)
277 { this->deps_.push_back(name); }
279 // Return whether this definition is weak.
282 { return this->is_weak_; }
284 // Clear the weak flag.
287 { this->is_weak_ = false; }
289 // Return whether a version symbol has been created for this
292 is_symbol_created() const
293 { return this->is_symbol_created_; }
295 // Write contents to buffer.
296 template<int size, bool big_endian>
298 write(const Stringpool*, bool is_last, unsigned char*
299 ACCEPT_SIZE_ENDIAN) const;
302 Verdef(const Verdef&);
303 Verdef& operator=(const Verdef&);
305 // The type of the list of version dependencies. Each dependency
306 // should be canonicalized in the dynamic Stringpool.
307 typedef std::vector<const char*> Deps;
309 // The name of this version. This should be canonicalized in the
310 // dynamic Stringpool.
312 // A list of other versions which this version depends upon.
314 // Whether this is the base version.
316 // Whether this version is weak.
318 // Whether a version symbol has been created.
319 bool is_symbol_created_;
322 // A referened version. This will be associated with a filename by
325 class Verneed_version : public Version_base
328 Verneed_version(const char* version)
332 // Return the version name.
335 { return this->version_; }
337 // Clear the weak flag. This is invalid for a reference.
340 { gold_unreachable(); }
343 Verneed_version(const Verneed_version&);
344 Verneed_version& operator=(const Verneed_version&);
346 const char* version_;
349 // Version references in a single dynamic object.
354 Verneed(const char* filename)
355 : filename_(filename), need_versions_()
360 // Return the file name.
363 { return this->filename_; }
365 // Return the number of versions.
367 count_versions() const
368 { return this->need_versions_.size(); }
370 // Add a version name. The name should be canonicalized in the
371 // dynamic Stringpool. If the name is already present, this does
374 add_name(const char* name);
376 // Set the version indexes, starting at INDEX. Return the updated
379 finalize(unsigned int index);
381 // Write contents to buffer.
382 template<int size, bool big_endian>
384 write(const Stringpool*, bool is_last, unsigned char*
385 ACCEPT_SIZE_ENDIAN) const;
388 Verneed(const Verneed&);
389 Verneed& operator=(const Verneed&);
391 // The type of the list of version names. Each name should be
392 // canonicalized in the dynamic Stringpool.
393 typedef std::vector<Verneed_version*> Need_versions;
395 // The filename of the dynamic object. This should be
396 // canonicalized in the dynamic Stringpool.
397 const char* filename_;
398 // The list of version names.
399 Need_versions need_versions_;
402 // This class handles version definitions and references which go into
409 : defs_(), needs_(), version_table_(), is_finalized_(false)
414 // SYM is going into the dynamic symbol table and has a version.
415 // Record the appropriate version information.
417 record_version(const Symbol_table* symtab, Stringpool*, const Symbol* sym);
419 // Set the version indexes. DYNSYM_INDEX is the index we should use
420 // for the next dynamic symbol. We add new dynamic symbols to SYMS
421 // and return an updated DYNSYM_INDEX.
423 finalize(const Target*, Symbol_table* symtab, unsigned int dynsym_index,
424 std::vector<Symbol*>* syms);
426 // Return whether there are any version definitions.
429 { return !this->defs_.empty(); }
431 // Return whether there are any version references.
434 { return !this->needs_.empty(); }
436 // Build an allocated buffer holding the contents of the symbol
437 // version section (.gnu.version).
438 template<int size, bool big_endian>
440 symbol_section_contents(const Symbol_table*, const Stringpool*,
441 unsigned int local_symcount,
442 const std::vector<Symbol*>& syms,
443 unsigned char**, unsigned int*
444 ACCEPT_SIZE_ENDIAN) const;
446 // Build an allocated buffer holding the contents of the version
447 // definition section (.gnu.version_d).
448 template<int size, bool big_endian>
450 def_section_contents(const Stringpool*, unsigned char**,
451 unsigned int* psize, unsigned int* pentries
452 ACCEPT_SIZE_ENDIAN) const;
454 // Build an allocated buffer holding the contents of the version
455 // reference section (.gnu.version_r).
456 template<int size, bool big_endian>
458 need_section_contents(const Stringpool*, unsigned char**,
459 unsigned int* psize, unsigned int* pentries
460 ACCEPT_SIZE_ENDIAN) const;
463 // The type of the list of version definitions.
464 typedef std::vector<Verdef*> Defs;
466 // The type of the list of version references.
467 typedef std::vector<Verneed*> Needs;
469 // Handle a symbol SYM defined with version VERSION.
471 add_def(const Symbol* sym, const char* version, Stringpool::Key);
473 // Add a reference to version NAME in file FILENAME.
475 add_need(Stringpool*, const char* filename, const char* name,
478 // Get the dynamic object to use for SYM.
480 get_dynobj_for_sym(const Symbol_table*, const Symbol* sym) const;
482 // Return the version index to use for SYM.
484 version_index(const Symbol_table*, const Stringpool*,
485 const Symbol* sym) const;
487 // We keep a hash table mapping canonicalized name/version pairs to
489 typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
491 struct Version_table_hash
494 operator()(const Key& k) const
495 { return k.first + k.second; }
498 struct Version_table_eq
501 operator()(const Key& k1, const Key& k2) const
502 { return k1.first == k2.first && k1.second == k2.second; }
505 typedef Unordered_map<Key, Version_base*, Version_table_hash,
506 Version_table_eq> Version_table;
508 // The version definitions.
510 // The version references.
512 // The mapping from a canonicalized version/filename pair to a
513 // version index. The filename may be NULL.
514 Version_table version_table_;
515 // Whether the version indexes have been set.
519 } // End namespace gold.
521 #endif // !defined(GOLD_DYNOBJ_H)