1 // dynobj.h -- dynamic object support for gold -*- C++ -*-
8 #include "stringpool.h"
14 class General_options;
16 // A dynamic object (ET_DYN). This is an abstract base class itself.
17 // The implementations is the template class Sized_dynobj.
19 class Dynobj : public Object
22 Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0)
23 : Object(name, input_file, true, offset), soname_()
26 // Return the name to use in a DT_NEEDED entry for this object.
30 // Compute the ELF hash code for a string.
32 elf_hash(const char*);
34 // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
35 // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the
36 // number of local dynamic symbols, which is the index of the first
37 // dynamic gobal symbol.
39 create_elf_hash_table(const Target*, const std::vector<Symbol*>& dynsyms,
40 unsigned int local_dynsym_count,
41 unsigned char** pphash,
42 unsigned int* phashlen);
44 // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS
45 // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number
46 // of local dynamic symbols, which is the index of the first dynamic
49 create_gnu_hash_table(const Target*, const std::vector<Symbol*>& dynsyms,
50 unsigned int local_dynsym_count,
51 unsigned char** pphash, unsigned int* phashlen);
54 // Set the DT_SONAME string.
56 set_soname_string(const char* s)
57 { this->soname_.assign(s); }
60 // Compute the GNU hash code for a string.
62 gnu_hash(const char*);
64 // Compute the number of hash buckets to use.
66 compute_bucket_count(const std::vector<uint32_t>& hashcodes,
67 bool for_gnu_hash_table);
69 // Sized version of create_elf_hash_table.
70 template<bool big_endian>
72 sized_create_elf_hash_table(const std::vector<uint32_t>& bucket,
73 const std::vector<uint32_t>& chain,
75 unsigned int hashlen);
77 // Sized version of create_gnu_hash_table.
78 template<int size, bool big_endian>
80 sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms,
81 const std::vector<uint32_t>& dynsym_hashvals,
82 unsigned int unhashed_dynsym_count,
83 unsigned char** pphash,
84 unsigned int* phashlen);
86 // The DT_SONAME name, if any.
90 // A dynamic object, size and endian specific version.
92 template<int size, bool big_endian>
93 class Sized_dynobj : public Dynobj
96 Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset,
97 const typename elfcpp::Ehdr<size, big_endian>&);
99 // Set up the object file based on the ELF header.
101 setup(const typename elfcpp::Ehdr<size, big_endian>&);
105 do_read_symbols(Read_symbols_data*);
107 // Lay out the input sections.
109 do_layout(Symbol_table*, Layout*, Read_symbols_data*);
111 // Add the symbols to the symbol table.
113 do_add_symbols(Symbol_table*, Read_symbols_data*);
115 // Get the name of a section.
117 do_section_name(unsigned int shndx)
118 { return this->elf_file_.section_name(shndx); }
120 // Return a view of the contents of a section. Set *PLEN to the
123 do_section_contents(unsigned int shndx)
124 { return this->elf_file_.section_contents(shndx); }
126 // Return section flags.
128 do_section_flags(unsigned int shndx)
129 { return this->elf_file_.section_flags(shndx); }
133 typedef Sized_dynobj<size, big_endian> This;
134 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
135 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
136 static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
137 typedef elfcpp::Shdr<size, big_endian> Shdr;
138 typedef elfcpp::Dyn<size, big_endian> Dyn;
140 // Find the dynamic symbol table and the version sections, given the
143 find_dynsym_sections(const unsigned char* pshdrs,
144 unsigned int* pdynshm_shndx,
145 unsigned int* pversym_shndx,
146 unsigned int* pverdef_shndx,
147 unsigned int* pverneed_shndx,
148 unsigned int* pdynamic_shndx);
150 // Read the dynamic symbol section SHNDX.
152 read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
153 elfcpp::SHT type, unsigned int link,
154 File_view** view, off_t* view_size,
155 unsigned int* view_info);
157 // Set the SONAME from the SHT_DYNAMIC section at DYNAMIC_SHNDX.
158 // The STRTAB parameters may have the relevant string table.
160 set_soname(const unsigned char* pshdrs, unsigned int dynamic_shndx,
161 unsigned int strtab_shndx, const unsigned char* strtabu,
164 // Mapping from version number to version name.
165 typedef std::vector<const char*> Version_map;
167 // Create the version map.
169 make_version_map(Read_symbols_data* sd, Version_map*) const;
171 // Add version definitions to the version map.
173 make_verdef_map(Read_symbols_data* sd, Version_map*) const;
175 // Add version references to the version map.
177 make_verneed_map(Read_symbols_data* sd, Version_map*) const;
179 // Add an entry to the version map.
181 set_version_map(Version_map*, unsigned int ndx, const char* name) const;
183 // General access to the ELF file.
184 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
187 // A base class for Verdef and Verneed_version which just handles the
188 // version index which will be stored in the SHT_GNU_versym section.
201 // Return the version index.
205 gold_assert(this->index_ != -1U);
209 // Set the version index.
211 set_index(unsigned int index)
213 gold_assert(this->index_ == -1U);
214 this->index_ = index;
217 // Clear the weak flag in a version definition.
222 Version_base(const Version_base&);
223 Version_base& operator=(const Version_base&);
225 // The index of the version definition or reference.
229 // This class handles a version being defined in the file we are
232 class Verdef : public Version_base
235 Verdef(const char* name, bool is_base, bool is_weak, bool is_symbol_created)
236 : name_(name), deps_(), is_base_(is_base), is_weak_(is_weak),
237 is_symbol_created_(is_symbol_created)
240 // Return the version name.
243 { return this->name_; }
245 // Return the number of dependencies.
247 count_dependencies() const
248 { return this->deps_.size(); }
250 // Add a dependency to this version. The NAME should be
251 // canonicalized in the dynamic Stringpool.
253 add_dependency(const char* name)
254 { this->deps_.push_back(name); }
256 // Return whether this definition is weak.
259 { return this->is_weak_; }
261 // Clear the weak flag.
264 { this->is_weak_ = false; }
266 // Return whether a version symbol has been created for this
269 is_symbol_created() const
270 { return this->is_symbol_created_; }
272 // Write contents to buffer.
273 template<int size, bool big_endian>
275 write(const Stringpool*, bool is_last, unsigned char*
276 ACCEPT_SIZE_ENDIAN) const;
279 Verdef(const Verdef&);
280 Verdef& operator=(const Verdef&);
282 // The type of the list of version dependencies. Each dependency
283 // should be canonicalized in the dynamic Stringpool.
284 typedef std::vector<const char*> Deps;
286 // The name of this version. This should be canonicalized in the
287 // dynamic Stringpool.
289 // A list of other versions which this version depends upon.
291 // Whether this is the base version.
293 // Whether this version is weak.
295 // Whether a version symbol has been created.
296 bool is_symbol_created_;
299 // A referened version. This will be associated with a filename by
302 class Verneed_version : public Version_base
305 Verneed_version(const char* version)
309 // Return the version name.
312 { return this->version_; }
314 // Clear the weak flag. This is invalid for a reference.
317 { gold_unreachable(); }
320 Verneed_version(const Verneed_version&);
321 Verneed_version& operator=(const Verneed_version&);
323 const char* version_;
326 // Version references in a single dynamic object.
331 Verneed(const char* filename)
332 : filename_(filename), need_versions_()
337 // Return the file name.
340 { return this->filename_; }
342 // Return the number of versions.
344 count_versions() const
345 { return this->need_versions_.size(); }
347 // Add a version name. The name should be canonicalized in the
348 // dynamic Stringpool. If the name is already present, this does
351 add_name(const char* name);
353 // Set the version indexes, starting at INDEX. Return the updated
356 finalize(unsigned int index);
358 // Write contents to buffer.
359 template<int size, bool big_endian>
361 write(const Stringpool*, bool is_last, unsigned char*
362 ACCEPT_SIZE_ENDIAN) const;
365 Verneed(const Verneed&);
366 Verneed& operator=(const Verneed&);
368 // The type of the list of version names. Each name should be
369 // canonicalized in the dynamic Stringpool.
370 typedef std::vector<Verneed_version*> Need_versions;
372 // The filename of the dynamic object. This should be
373 // canonicalized in the dynamic Stringpool.
374 const char* filename_;
375 // The list of version names.
376 Need_versions need_versions_;
379 // This class handles version definitions and references which go into
386 : defs_(), needs_(), version_table_(), is_finalized_(false)
391 // SYM is going into the dynamic symbol table and has a version.
392 // Record the appropriate version information.
394 record_version(const General_options*, Stringpool*, const Symbol* sym);
396 // Set the version indexes. DYNSYM_INDEX is the index we should use
397 // for the next dynamic symbol. We add new dynamic symbols to SYMS
398 // and return an updated DYNSYM_INDEX.
400 finalize(const Target*, Symbol_table* symtab, unsigned int dynsym_index,
401 std::vector<Symbol*>* syms);
403 // Return whether there are any version definitions.
406 { return !this->defs_.empty(); }
408 // Return whether there are any version references.
411 { return !this->needs_.empty(); }
413 // Build an allocated buffer holding the contents of the symbol
414 // version section (.gnu.version).
415 template<int size, bool big_endian>
417 symbol_section_contents(const Stringpool*, unsigned int local_symcount,
418 const std::vector<Symbol*>& syms,
419 unsigned char**, unsigned int*
420 ACCEPT_SIZE_ENDIAN) const;
422 // Build an allocated buffer holding the contents of the version
423 // definition section (.gnu.version_d).
424 template<int size, bool big_endian>
426 def_section_contents(const Stringpool*, unsigned char**,
427 unsigned int* psize, unsigned int* pentries
428 ACCEPT_SIZE_ENDIAN) const;
430 // Build an allocated buffer holding the contents of the version
431 // reference section (.gnu.version_r).
432 template<int size, bool big_endian>
434 need_section_contents(const Stringpool*, unsigned char**,
435 unsigned int* psize, unsigned int* pentries
436 ACCEPT_SIZE_ENDIAN) const;
439 // The type of the list of version definitions.
440 typedef std::vector<Verdef*> Defs;
442 // The type of the list of version references.
443 typedef std::vector<Verneed*> Needs;
445 // Handle a symbol SYM defined with version VERSION.
447 add_def(const General_options*, const Symbol* sym, const char* version,
450 // Add a reference to version NAME in file FILENAME.
452 add_need(Stringpool*, const char* filename, const char* name,
455 // Return the version index to use for SYM.
457 version_index(const Stringpool*, const Symbol* sym) const;
459 // We keep a hash table mapping canonicalized name/version pairs to
461 typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
463 struct Version_table_hash
466 operator()(const Key& k) const
467 { return k.first + k.second; }
470 struct Version_table_eq
473 operator()(const Key& k1, const Key& k2) const
474 { return k1.first == k2.first && k1.second == k2.second; }
477 typedef Unordered_map<Key, Version_base*, Version_table_hash,
478 Version_table_eq> Version_table;
480 // The version definitions.
482 // The version references.
484 // The mapping from a canonicalized version/filename pair to a
485 // version index. The filename may be NULL.
486 Version_table version_table_;
487 // Whether the version indexes have been set.
491 } // End namespace gold.
493 #endif // !defined(GOLD_DYNOBJ_H)