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.
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 TARGET.
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 Archive::Should_include
181 do_should_include_member(Symbol_table* symtab, Layout*, Read_symbols_data*,
184 // Iterate over global symbols, calling a visitor class V for each.
186 do_for_all_global_symbols(Read_symbols_data* sd,
187 Library_base::Symbol_visitor_base* v);
189 // Get the size of a section.
191 do_section_size(unsigned int shndx)
192 { return this->elf_file_.section_size(shndx); }
194 // Get the name of a section.
196 do_section_name(unsigned int shndx)
197 { return this->elf_file_.section_name(shndx); }
199 // Return a view of the contents of a section. Set *PLEN to the
202 do_section_contents(unsigned int shndx)
203 { return this->elf_file_.section_contents(shndx); }
205 // Return section flags.
207 do_section_flags(unsigned int shndx)
208 { return this->elf_file_.section_flags(shndx); }
210 // Not used for dynobj.
212 do_section_entsize(unsigned int )
213 { gold_unreachable(); }
215 // Return section address.
217 do_section_address(unsigned int shndx)
218 { return this->elf_file_.section_addr(shndx); }
220 // Return section type.
222 do_section_type(unsigned int shndx)
223 { return this->elf_file_.section_type(shndx); }
225 // Return the section link field.
227 do_section_link(unsigned int shndx)
228 { return this->elf_file_.section_link(shndx); }
230 // Return the section link field.
232 do_section_info(unsigned int shndx)
233 { return this->elf_file_.section_info(shndx); }
235 // Return the section alignment.
237 do_section_addralign(unsigned int shndx)
238 { return this->elf_file_.section_addralign(shndx); }
240 // Return the Xindex structure to use.
242 do_initialize_xindex();
244 // Get symbol counts.
246 do_get_global_symbol_counts(const Symbol_table*, size_t*, size_t*) const;
248 // Get the global symbols.
250 do_get_global_symbols() const
251 { return this->symbols_; }
255 typedef Sized_dynobj<size, big_endian> This;
256 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
257 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
258 static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
259 typedef elfcpp::Shdr<size, big_endian> Shdr;
260 typedef elfcpp::Dyn<size, big_endian> Dyn;
262 // Adjust a section index if necessary.
264 adjust_shndx(unsigned int shndx)
266 if (shndx >= elfcpp::SHN_LORESERVE)
267 shndx += this->elf_file_.large_shndx_offset();
271 // Find the dynamic symbol table and the version sections, given the
274 find_dynsym_sections(const unsigned char* pshdrs,
275 unsigned int* pversym_shndx,
276 unsigned int* pverdef_shndx,
277 unsigned int* pverneed_shndx,
278 unsigned int* pdynamic_shndx);
280 // Read the dynamic symbol section SHNDX.
282 read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
283 elfcpp::SHT type, unsigned int link,
284 File_view** view, section_size_type* view_size,
285 unsigned int* view_info);
287 // Read the dynamic tags.
289 read_dynamic(const unsigned char* pshdrs, unsigned int dynamic_shndx,
290 unsigned int strtab_shndx, const unsigned char* strtabu,
293 // Mapping from version number to version name.
294 typedef std::vector<const char*> Version_map;
296 // Create the version map.
298 make_version_map(Read_symbols_data* sd, Version_map*) const;
300 // Add version definitions to the version map.
302 make_verdef_map(Read_symbols_data* sd, Version_map*) const;
304 // Add version references to the version map.
306 make_verneed_map(Read_symbols_data* sd, Version_map*) const;
308 // Add an entry to the version map.
310 set_version_map(Version_map*, unsigned int ndx, const char* name) const;
312 // General access to the ELF file.
313 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
314 // The section index of the dynamic symbol table.
315 unsigned int dynsym_shndx_;
316 // The entries in the symbol table for the symbols. We only keep
317 // this if we need it to print symbol information.
319 // Number of defined symbols.
320 size_t defined_count_;
323 // A base class for Verdef and Verneed_version which just handles the
324 // version index which will be stored in the SHT_GNU_versym section.
337 // Return the version index.
341 gold_assert(this->index_ != -1U);
345 // Set the version index.
347 set_index(unsigned int index)
349 gold_assert(this->index_ == -1U);
350 this->index_ = index;
353 // Clear the weak flag in a version definition.
358 Version_base(const Version_base&);
359 Version_base& operator=(const Version_base&);
361 // The index of the version definition or reference.
365 // This class handles a version being defined in the file we are
368 class Verdef : public Version_base
371 Verdef(const char* name, const std::vector<std::string>& deps,
372 bool is_base, bool is_weak, bool is_info, bool is_symbol_created)
373 : name_(name), deps_(deps), is_base_(is_base), is_weak_(is_weak),
374 is_info_(is_info), is_symbol_created_(is_symbol_created)
377 // Return the version name.
380 { return this->name_; }
382 // Return the number of dependencies.
384 count_dependencies() const
385 { return this->deps_.size(); }
387 // Add a dependency to this version. The NAME should be
388 // canonicalized in the dynamic Stringpool.
390 add_dependency(const char* name)
391 { this->deps_.push_back(name); }
393 // Return whether this definition is weak.
396 { return this->is_weak_; }
398 // Clear the weak flag.
401 { this->is_weak_ = false; }
403 // Return whether this definition is informational.
406 { return this->is_info_; }
408 // Return whether a version symbol has been created for this
411 is_symbol_created() const
412 { return this->is_symbol_created_; }
414 // Write contents to buffer.
415 template<int size, bool big_endian>
417 write(const Stringpool*, bool is_last, unsigned char*) const;
420 Verdef(const Verdef&);
421 Verdef& operator=(const Verdef&);
423 // The type of the list of version dependencies. Each dependency
424 // should be canonicalized in the dynamic Stringpool.
425 typedef std::vector<std::string> Deps;
427 // The name of this version. This should be canonicalized in the
428 // dynamic Stringpool.
430 // A list of other versions which this version depends upon.
432 // Whether this is the base version.
434 // Whether this version is weak.
436 // Whether this version is informational.
438 // Whether a version symbol has been created.
439 bool is_symbol_created_;
442 // A referened version. This will be associated with a filename by
445 class Verneed_version : public Version_base
448 Verneed_version(const char* version)
452 // Return the version name.
455 { return this->version_; }
457 // Clear the weak flag. This is invalid for a reference.
460 { gold_unreachable(); }
463 Verneed_version(const Verneed_version&);
464 Verneed_version& operator=(const Verneed_version&);
466 const char* version_;
469 // Version references in a single dynamic object.
474 Verneed(const char* filename)
475 : filename_(filename), need_versions_()
480 // Return the file name.
483 { return this->filename_; }
485 // Return the number of versions.
487 count_versions() const
488 { return this->need_versions_.size(); }
490 // Add a version name. The name should be canonicalized in the
491 // dynamic Stringpool. If the name is already present, this does
494 add_name(const char* name);
496 // Set the version indexes, starting at INDEX. Return the updated
499 finalize(unsigned int index);
501 // Write contents to buffer.
502 template<int size, bool big_endian>
504 write(const Stringpool*, bool is_last, unsigned char*) const;
507 Verneed(const Verneed&);
508 Verneed& operator=(const Verneed&);
510 // The type of the list of version names. Each name should be
511 // canonicalized in the dynamic Stringpool.
512 typedef std::vector<Verneed_version*> Need_versions;
514 // The filename of the dynamic object. This should be
515 // canonicalized in the dynamic Stringpool.
516 const char* filename_;
517 // The list of version names.
518 Need_versions need_versions_;
521 // This class handles version definitions and references which go into
527 Versions(const Version_script_info&, Stringpool*);
531 // SYM is going into the dynamic symbol table and has a version.
532 // Record the appropriate version information.
534 record_version(const Symbol_table* symtab, Stringpool*, const Symbol* sym);
536 // Set the version indexes. DYNSYM_INDEX is the index we should use
537 // for the next dynamic symbol. We add new dynamic symbols to SYMS
538 // and return an updated DYNSYM_INDEX.
540 finalize(Symbol_table* symtab, unsigned int dynsym_index,
541 std::vector<Symbol*>* syms);
543 // Return whether there are any version definitions.
546 { return !this->defs_.empty(); }
548 // Return whether there are any version references.
551 { return !this->needs_.empty(); }
553 // Build an allocated buffer holding the contents of the symbol
554 // version section (.gnu.version).
555 template<int size, bool big_endian>
557 symbol_section_contents(const Symbol_table*, const Stringpool*,
558 unsigned int local_symcount,
559 const std::vector<Symbol*>& syms,
560 unsigned char**, unsigned int*) const;
562 // Build an allocated buffer holding the contents of the version
563 // definition section (.gnu.version_d).
564 template<int size, bool big_endian>
566 def_section_contents(const Stringpool*, unsigned char**,
567 unsigned int* psize, unsigned int* pentries) const;
569 // Build an allocated buffer holding the contents of the version
570 // reference section (.gnu.version_r).
571 template<int size, bool big_endian>
573 need_section_contents(const Stringpool*, unsigned char**,
574 unsigned int* psize, unsigned int* pentries) const;
576 const Version_script_info&
577 version_script() const
578 { return this->version_script_; }
581 Versions(const Versions&);
582 Versions& operator=(const Versions&);
584 // The type of the list of version definitions.
585 typedef std::vector<Verdef*> Defs;
587 // The type of the list of version references.
588 typedef std::vector<Verneed*> Needs;
590 // Handle a symbol SYM defined with version VERSION.
592 add_def(const Symbol* sym, const char* version, Stringpool::Key);
594 // Add a reference to version NAME in file FILENAME.
596 add_need(Stringpool*, const char* filename, const char* name,
599 // Get the dynamic object to use for SYM.
601 get_dynobj_for_sym(const Symbol_table*, const Symbol* sym) const;
603 // Return the version index to use for SYM.
605 version_index(const Symbol_table*, const Stringpool*,
606 const Symbol* sym) const;
608 // Define the base version of a shared library.
610 define_base_version(Stringpool* dynpool);
612 // We keep a hash table mapping canonicalized name/version pairs to
614 typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
616 struct Version_table_hash
619 operator()(const Key& k) const
620 { return k.first + k.second; }
623 struct Version_table_eq
626 operator()(const Key& k1, const Key& k2) const
627 { return k1.first == k2.first && k1.second == k2.second; }
630 typedef Unordered_map<Key, Version_base*, Version_table_hash,
631 Version_table_eq> Version_table;
633 // The version definitions.
635 // The version references.
637 // The mapping from a canonicalized version/filename pair to a
638 // version index. The filename may be NULL.
639 Version_table version_table_;
640 // Whether the version indexes have been set.
642 // Contents of --version-script, if passed, or NULL.
643 const Version_script_info& version_script_;
644 // Whether we need to insert a base version. This is only used for
645 // shared libaries and is cleared when the base version is defined.
646 bool needs_base_version_;
649 } // End namespace gold.
651 #endif // !defined(GOLD_DYNOBJ_H)