1 // dynobj.h -- dynamic object support for gold -*- C++ -*-
8 #include "stringpool.h"
14 class General_options;
17 // A dynamic object (ET_DYN). This is an abstract base class itself.
18 // The implementations is the template class Sized_dynobj.
20 class Dynobj : public Object
23 Dynobj(const std::string& name, Input_file* input_file, off_t offset = 0)
24 : Object(name, input_file, true, offset), soname_()
27 // Return the name to use in a DT_NEEDED entry for this object.
31 // Compute the ELF hash code for a string.
33 elf_hash(const char*);
35 // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
36 // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the
37 // number of local dynamic symbols, which is the index of the first
38 // dynamic gobal symbol.
40 create_elf_hash_table(const Target*, const std::vector<Symbol*>& dynsyms,
41 unsigned int local_dynsym_count,
42 unsigned char** pphash,
43 unsigned int* phashlen);
45 // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS
46 // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number
47 // of local dynamic symbols, which is the index of the first dynamic
50 create_gnu_hash_table(const Target*, const std::vector<Symbol*>& dynsyms,
51 unsigned int local_dynsym_count,
52 unsigned char** pphash, unsigned int* phashlen);
55 // Set the DT_SONAME string.
57 set_soname_string(const char* s)
58 { this->soname_.assign(s); }
61 // Compute the GNU hash code for a string.
63 gnu_hash(const char*);
65 // Compute the number of hash buckets to use.
67 compute_bucket_count(const std::vector<uint32_t>& hashcodes,
68 bool for_gnu_hash_table);
70 // Sized version of create_elf_hash_table.
71 template<bool big_endian>
73 sized_create_elf_hash_table(const std::vector<uint32_t>& bucket,
74 const std::vector<uint32_t>& chain,
76 unsigned int hashlen);
78 // Sized version of create_gnu_hash_table.
79 template<int size, bool big_endian>
81 sized_create_gnu_hash_table(const std::vector<Symbol*>& hashed_dynsyms,
82 const std::vector<uint32_t>& dynsym_hashvals,
83 unsigned int unhashed_dynsym_count,
84 unsigned char** pphash,
85 unsigned int* phashlen);
87 // The DT_SONAME name, if any.
91 // A dynamic object, size and endian specific version.
93 template<int size, bool big_endian>
94 class Sized_dynobj : public Dynobj
97 Sized_dynobj(const std::string& name, Input_file* input_file, off_t offset,
98 const typename elfcpp::Ehdr<size, big_endian>&);
100 // Set up the object file based on the ELF header.
102 setup(const typename elfcpp::Ehdr<size, big_endian>&);
106 do_read_symbols(Read_symbols_data*);
108 // Lay out the input sections.
110 do_layout(const General_options&, Symbol_table*, Layout*,
113 // Add the symbols to the symbol table.
115 do_add_symbols(Symbol_table*, Read_symbols_data*);
117 // Get the name of a section.
119 do_section_name(unsigned int shndx)
120 { return this->elf_file_.section_name(shndx); }
122 // Return a view of the contents of a section. Set *PLEN to the
125 do_section_contents(unsigned int shndx)
126 { return this->elf_file_.section_contents(shndx); }
128 // Return section flags.
130 do_section_flags(unsigned int shndx)
131 { return this->elf_file_.section_flags(shndx); }
135 typedef Sized_dynobj<size, big_endian> This;
136 static const int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
137 static const int sym_size = elfcpp::Elf_sizes<size>::sym_size;
138 static const int dyn_size = elfcpp::Elf_sizes<size>::dyn_size;
139 typedef elfcpp::Shdr<size, big_endian> Shdr;
140 typedef elfcpp::Dyn<size, big_endian> Dyn;
142 // Find the dynamic symbol table and the version sections, given the
145 find_dynsym_sections(const unsigned char* pshdrs,
146 unsigned int* pdynshm_shndx,
147 unsigned int* pversym_shndx,
148 unsigned int* pverdef_shndx,
149 unsigned int* pverneed_shndx,
150 unsigned int* pdynamic_shndx);
152 // Read the dynamic symbol section SHNDX.
154 read_dynsym_section(const unsigned char* pshdrs, unsigned int shndx,
155 elfcpp::SHT type, unsigned int link,
156 File_view** view, off_t* view_size,
157 unsigned int* view_info);
159 // Set the SONAME from the SHT_DYNAMIC section at DYNAMIC_SHNDX.
160 // The STRTAB parameters may have the relevant string table.
162 set_soname(const unsigned char* pshdrs, unsigned int dynamic_shndx,
163 unsigned int strtab_shndx, const unsigned char* strtabu,
166 // Mapping from version number to version name.
167 typedef std::vector<const char*> Version_map;
169 // Create the version map.
171 make_version_map(Read_symbols_data* sd, Version_map*) const;
173 // Add version definitions to the version map.
175 make_verdef_map(Read_symbols_data* sd, Version_map*) const;
177 // Add version references to the version map.
179 make_verneed_map(Read_symbols_data* sd, Version_map*) const;
181 // Add an entry to the version map.
183 set_version_map(Version_map*, unsigned int ndx, const char* name) const;
185 // General access to the ELF file.
186 elfcpp::Elf_file<size, big_endian, Object> elf_file_;
189 // A base class for Verdef and Verneed_version which just handles the
190 // version index which will be stored in the SHT_GNU_versym section.
203 // Return the version index.
207 gold_assert(this->index_ != -1U);
211 // Set the version index.
213 set_index(unsigned int index)
215 gold_assert(this->index_ == -1U);
216 this->index_ = index;
219 // Clear the weak flag in a version definition.
224 Version_base(const Version_base&);
225 Version_base& operator=(const Version_base&);
227 // The index of the version definition or reference.
231 // This class handles a version being defined in the file we are
234 class Verdef : public Version_base
237 Verdef(const char* name, bool is_base, bool is_weak, bool is_symbol_created)
238 : name_(name), deps_(), is_base_(is_base), is_weak_(is_weak),
239 is_symbol_created_(is_symbol_created)
242 // Return the version name.
245 { return this->name_; }
247 // Return the number of dependencies.
249 count_dependencies() const
250 { return this->deps_.size(); }
252 // Add a dependency to this version. The NAME should be
253 // canonicalized in the dynamic Stringpool.
255 add_dependency(const char* name)
256 { this->deps_.push_back(name); }
258 // Return whether this definition is weak.
261 { return this->is_weak_; }
263 // Clear the weak flag.
266 { this->is_weak_ = false; }
268 // Return whether a version symbol has been created for this
271 is_symbol_created() const
272 { return this->is_symbol_created_; }
274 // Write contents to buffer.
275 template<int size, bool big_endian>
277 write(const Stringpool*, bool is_last, unsigned char*) const;
280 Verdef(const Verdef&);
281 Verdef& operator=(const Verdef&);
283 // The type of the list of version dependencies. Each dependency
284 // should be canonicalized in the dynamic Stringpool.
285 typedef std::vector<const char*> Deps;
287 // The name of this version. This should be canonicalized in the
288 // dynamic Stringpool.
290 // A list of other versions which this version depends upon.
292 // Whether this is the base version.
294 // Whether this version is weak.
296 // Whether a version symbol has been created.
297 bool is_symbol_created_;
300 // A referened version. This will be associated with a filename by
303 class Verneed_version : public Version_base
306 Verneed_version(const char* version)
310 // Return the version name.
313 { return this->version_; }
315 // Clear the weak flag. This is invalid for a reference.
318 { gold_unreachable(); }
321 Verneed_version(const Verneed_version&);
322 Verneed_version& operator=(const Verneed_version&);
324 const char* version_;
327 // Version references in a single dynamic object.
332 Verneed(const char* filename)
333 : filename_(filename), need_versions_()
338 // Return the file name.
341 { return this->filename_; }
343 // Return the number of versions.
345 count_versions() const
346 { return this->need_versions_.size(); }
348 // Add a version name. The name should be canonicalized in the
349 // dynamic Stringpool. If the name is already present, this does
352 add_name(const char* name);
354 // Set the version indexes, starting at INDEX. Return the updated
357 finalize(unsigned int index);
359 // Write contents to buffer.
360 template<int size, bool big_endian>
362 write(const Stringpool*, bool is_last, unsigned char*) 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*) const;
421 // Build an allocated buffer holding the contents of the version
422 // definition section (.gnu.version_d).
423 template<int size, bool big_endian>
425 def_section_contents(const Stringpool*, unsigned char**,
426 unsigned int* psize, unsigned int* pentries) const;
428 // Build an allocated buffer holding the contents of the version
429 // reference section (.gnu.version_r).
430 template<int size, bool big_endian>
432 need_section_contents(const Stringpool*, unsigned char**,
433 unsigned int* psize, unsigned int* pentries) const;
436 // The type of the list of version definitions.
437 typedef std::vector<Verdef*> Defs;
439 // The type of the list of version references.
440 typedef std::vector<Verneed*> Needs;
442 // Handle a symbol SYM defined with version VERSION.
444 add_def(const General_options*, const Symbol* sym, const char* version,
447 // Add a reference to version NAME in file FILENAME.
449 add_need(Stringpool*, const char* filename, const char* name,
452 // Return the version index to use for SYM.
454 version_index(const Stringpool*, const Symbol* sym) const;
456 // We keep a hash table mapping canonicalized name/version pairs to
458 typedef std::pair<Stringpool::Key, Stringpool::Key> Key;
460 struct Version_table_hash
463 operator()(const Key& k) const
464 { return k.first + k.second; }
467 struct Version_table_eq
470 operator()(const Key& k1, const Key& k2) const
471 { return k1.first == k2.first && k1.second == k2.second; }
474 typedef Unordered_map<Key, Version_base*, Version_table_hash,
475 Version_table_eq> Version_table;
477 // The version definitions.
479 // The version references.
481 // The mapping from a canonicalized version/filename pair to a
482 // version index. The filename may be NULL.
483 Version_table version_table_;
484 // Whether the version indexes have been set.
488 } // End namespace gold.
490 #endif // !defined(GOLD_DYNOBJ_H)