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
;
35 class Version_script_info
;
37 // A dynamic object (ET_DYN). This is an abstract base class itself.
38 // The implementations is the template class Sized_dynobj.
40 class Dynobj
: public Object
43 // We keep a list of all the DT_NEEDED entries we find.
44 typedef std::vector
<std::string
> Needed
;
46 Dynobj(const std::string
& name
, Input_file
* input_file
, off_t offset
= 0);
48 // Return the name to use in a DT_NEEDED entry for this object.
51 { return this->soname_
.c_str(); }
53 // Return the list of DT_NEEDED strings.
56 { return this->needed_
; }
58 // Return whether this dynamic object has any DT_NEEDED entries
59 // which were not seen during the link.
61 has_unknown_needed_entries() const
63 gold_assert(this->unknown_needed_
!= UNKNOWN_NEEDED_UNSET
);
64 return this->unknown_needed_
== UNKNOWN_NEEDED_TRUE
;
67 // Set whether this dynamic object has any DT_NEEDED entries which
68 // were not seen during the link.
70 set_has_unknown_needed_entries(bool set
)
72 gold_assert(this->unknown_needed_
== UNKNOWN_NEEDED_UNSET
);
73 this->unknown_needed_
= set
? UNKNOWN_NEEDED_TRUE
: UNKNOWN_NEEDED_FALSE
;
76 // Compute the ELF hash code for a string.
78 elf_hash(const char*);
80 // Create a standard ELF hash table, setting *PPHASH and *PHASHLEN.
81 // DYNSYMS is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the
82 // number of local dynamic symbols, which is the index of the first
83 // dynamic gobal symbol.
85 create_elf_hash_table(const std::vector
<Symbol
*>& dynsyms
,
86 unsigned int local_dynsym_count
,
87 unsigned char** pphash
,
88 unsigned int* phashlen
);
90 // Create a GNU hash table, setting *PPHASH and *PHASHLEN. DYNSYMS
91 // is the global dynamic symbols. LOCAL_DYNSYM_COUNT is the number
92 // of local dynamic symbols, which is the index of the first dynamic
95 create_gnu_hash_table(const std::vector
<Symbol
*>& dynsyms
,
96 unsigned int local_dynsym_count
,
97 unsigned char** pphash
, unsigned int* phashlen
);
100 // Set the DT_SONAME string.
102 set_soname_string(const char* s
)
103 { this->soname_
.assign(s
); }
105 // Add an entry to the list of DT_NEEDED strings.
107 add_needed(const char* s
)
108 { this->needed_
.push_back(std::string(s
)); }
111 // Compute the GNU hash code for a string.
113 gnu_hash(const char*);
115 // Compute the number of hash buckets to use.
117 compute_bucket_count(const std::vector
<uint32_t>& hashcodes
,
118 bool for_gnu_hash_table
);
120 // Sized version of create_elf_hash_table.
121 template<bool big_endian
>
123 sized_create_elf_hash_table(const std::vector
<uint32_t>& bucket
,
124 const std::vector
<uint32_t>& chain
,
125 unsigned char* phash
,
126 unsigned int hashlen
);
128 // Sized version of create_gnu_hash_table.
129 template<int size
, bool big_endian
>
131 sized_create_gnu_hash_table(const std::vector
<Symbol
*>& hashed_dynsyms
,
132 const std::vector
<uint32_t>& dynsym_hashvals
,
133 unsigned int unhashed_dynsym_count
,
134 unsigned char** pphash
,
135 unsigned int* phashlen
);
137 // Values for the has_unknown_needed_entries_ field.
140 UNKNOWN_NEEDED_UNSET
,
145 // The DT_SONAME name, if any.
147 // The list of DT_NEEDED entries.
149 // Whether this dynamic object has any DT_NEEDED entries not seen
151 Unknown_needed unknown_needed_
;
154 // A dynamic object, size and endian specific version.
156 template<int size
, bool big_endian
>
157 class Sized_dynobj
: public Dynobj
160 Sized_dynobj(const std::string
& name
, Input_file
* input_file
, off_t offset
,
161 const typename
elfcpp::Ehdr
<size
, big_endian
>&);
163 // Set up the object file based on the ELF header.
165 setup(const typename
elfcpp::Ehdr
<size
, big_endian
>&);
169 do_read_symbols(Read_symbols_data
*);
171 // Lay out the input sections.
173 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*);
175 // Add the symbols to the symbol table.
177 do_add_symbols(Symbol_table
*, Read_symbols_data
*);
179 // Get the name of a section.
181 do_section_name(unsigned int shndx
)
182 { return this->elf_file_
.section_name(shndx
); }
184 // Return a view of the contents of a section. Set *PLEN to the
187 do_section_contents(unsigned int shndx
)
188 { return this->elf_file_
.section_contents(shndx
); }
190 // Return section flags.
192 do_section_flags(unsigned int shndx
)
193 { return this->elf_file_
.section_flags(shndx
); }
195 // Return section type.
197 do_section_type(unsigned int shndx
)
198 { return this->elf_file_
.section_type(shndx
); }
200 // Return the section link field.
202 do_section_link(unsigned int shndx
)
203 { return this->elf_file_
.section_link(shndx
); }
205 // Return the section link field.
207 do_section_info(unsigned int shndx
)
208 { return this->elf_file_
.section_info(shndx
); }
212 typedef Sized_dynobj
<size
, big_endian
> This
;
213 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
214 static const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
215 static const int dyn_size
= elfcpp::Elf_sizes
<size
>::dyn_size
;
216 typedef elfcpp::Shdr
<size
, big_endian
> Shdr
;
217 typedef elfcpp::Dyn
<size
, big_endian
> Dyn
;
219 // Find the dynamic symbol table and the version sections, given the
222 find_dynsym_sections(const unsigned char* pshdrs
,
223 unsigned int* pdynshm_shndx
,
224 unsigned int* pversym_shndx
,
225 unsigned int* pverdef_shndx
,
226 unsigned int* pverneed_shndx
,
227 unsigned int* pdynamic_shndx
);
229 // Read the dynamic symbol section SHNDX.
231 read_dynsym_section(const unsigned char* pshdrs
, unsigned int shndx
,
232 elfcpp::SHT type
, unsigned int link
,
233 File_view
** view
, section_size_type
* view_size
,
234 unsigned int* view_info
);
236 // Read the dynamic tags.
238 read_dynamic(const unsigned char* pshdrs
, unsigned int dynamic_shndx
,
239 unsigned int strtab_shndx
, const unsigned char* strtabu
,
242 // Mapping from version number to version name.
243 typedef std::vector
<const char*> Version_map
;
245 // Create the version map.
247 make_version_map(Read_symbols_data
* sd
, Version_map
*) const;
249 // Add version definitions to the version map.
251 make_verdef_map(Read_symbols_data
* sd
, Version_map
*) const;
253 // Add version references to the version map.
255 make_verneed_map(Read_symbols_data
* sd
, Version_map
*) const;
257 // Add an entry to the version map.
259 set_version_map(Version_map
*, unsigned int ndx
, const char* name
) const;
261 // General access to the ELF file.
262 elfcpp::Elf_file
<size
, big_endian
, Object
> elf_file_
;
265 // A base class for Verdef and Verneed_version which just handles the
266 // version index which will be stored in the SHT_GNU_versym section.
279 // Return the version index.
283 gold_assert(this->index_
!= -1U);
287 // Set the version index.
289 set_index(unsigned int index
)
291 gold_assert(this->index_
== -1U);
292 this->index_
= index
;
295 // Clear the weak flag in a version definition.
300 Version_base(const Version_base
&);
301 Version_base
& operator=(const Version_base
&);
303 // The index of the version definition or reference.
307 // This class handles a version being defined in the file we are
310 class Verdef
: public Version_base
313 Verdef(const char* name
, const std::vector
<std::string
>& deps
,
314 bool is_base
, bool is_weak
, bool is_symbol_created
)
315 : name_(name
), deps_(deps
), is_base_(is_base
), is_weak_(is_weak
),
316 is_symbol_created_(is_symbol_created
)
319 // Return the version name.
322 { return this->name_
; }
324 // Return the number of dependencies.
326 count_dependencies() const
327 { return this->deps_
.size(); }
329 // Add a dependency to this version. The NAME should be
330 // canonicalized in the dynamic Stringpool.
332 add_dependency(const char* name
)
333 { this->deps_
.push_back(name
); }
335 // Return whether this definition is weak.
338 { return this->is_weak_
; }
340 // Clear the weak flag.
343 { this->is_weak_
= false; }
345 // Return whether a version symbol has been created for this
348 is_symbol_created() const
349 { return this->is_symbol_created_
; }
351 // Write contents to buffer.
352 template<int size
, bool big_endian
>
354 write(const Stringpool
*, bool is_last
, unsigned char*
355 ACCEPT_SIZE_ENDIAN
) const;
358 Verdef(const Verdef
&);
359 Verdef
& operator=(const Verdef
&);
361 // The type of the list of version dependencies. Each dependency
362 // should be canonicalized in the dynamic Stringpool.
363 typedef std::vector
<std::string
> Deps
;
365 // The name of this version. This should be canonicalized in the
366 // dynamic Stringpool.
368 // A list of other versions which this version depends upon.
370 // Whether this is the base version.
372 // Whether this version is weak.
374 // Whether a version symbol has been created.
375 bool is_symbol_created_
;
378 // A referened version. This will be associated with a filename by
381 class Verneed_version
: public Version_base
384 Verneed_version(const char* version
)
388 // Return the version name.
391 { return this->version_
; }
393 // Clear the weak flag. This is invalid for a reference.
396 { gold_unreachable(); }
399 Verneed_version(const Verneed_version
&);
400 Verneed_version
& operator=(const Verneed_version
&);
402 const char* version_
;
405 // Version references in a single dynamic object.
410 Verneed(const char* filename
)
411 : filename_(filename
), need_versions_()
416 // Return the file name.
419 { return this->filename_
; }
421 // Return the number of versions.
423 count_versions() const
424 { return this->need_versions_
.size(); }
426 // Add a version name. The name should be canonicalized in the
427 // dynamic Stringpool. If the name is already present, this does
430 add_name(const char* name
);
432 // Set the version indexes, starting at INDEX. Return the updated
435 finalize(unsigned int index
);
437 // Write contents to buffer.
438 template<int size
, bool big_endian
>
440 write(const Stringpool
*, bool is_last
, unsigned char*
441 ACCEPT_SIZE_ENDIAN
) const;
444 Verneed(const Verneed
&);
445 Verneed
& operator=(const Verneed
&);
447 // The type of the list of version names. Each name should be
448 // canonicalized in the dynamic Stringpool.
449 typedef std::vector
<Verneed_version
*> Need_versions
;
451 // The filename of the dynamic object. This should be
452 // canonicalized in the dynamic Stringpool.
453 const char* filename_
;
454 // The list of version names.
455 Need_versions need_versions_
;
458 // This class handles version definitions and references which go into
464 Versions(const General_options
&, Stringpool
*);
468 // SYM is going into the dynamic symbol table and has a version.
469 // Record the appropriate version information.
471 record_version(const Symbol_table
* symtab
, Stringpool
*, const Symbol
* sym
);
473 // Set the version indexes. DYNSYM_INDEX is the index we should use
474 // for the next dynamic symbol. We add new dynamic symbols to SYMS
475 // and return an updated DYNSYM_INDEX.
477 finalize(Symbol_table
* symtab
, unsigned int dynsym_index
,
478 std::vector
<Symbol
*>* syms
);
480 // Return whether there are any version definitions.
483 { return !this->defs_
.empty(); }
485 // Return whether there are any version references.
488 { return !this->needs_
.empty(); }
490 // Build an allocated buffer holding the contents of the symbol
491 // version section (.gnu.version).
492 template<int size
, bool big_endian
>
494 symbol_section_contents(const Symbol_table
*, const Stringpool
*,
495 unsigned int local_symcount
,
496 const std::vector
<Symbol
*>& syms
,
497 unsigned char**, unsigned int*
498 ACCEPT_SIZE_ENDIAN
) const;
500 // Build an allocated buffer holding the contents of the version
501 // definition section (.gnu.version_d).
502 template<int size
, bool big_endian
>
504 def_section_contents(const Stringpool
*, unsigned char**,
505 unsigned int* psize
, unsigned int* pentries
506 ACCEPT_SIZE_ENDIAN
) const;
508 // Build an allocated buffer holding the contents of the version
509 // reference section (.gnu.version_r).
510 template<int size
, bool big_endian
>
512 need_section_contents(const Stringpool
*, unsigned char**,
513 unsigned int* psize
, unsigned int* pentries
514 ACCEPT_SIZE_ENDIAN
) const;
516 const Version_script_info
&
517 version_script() const
518 { return this->version_script_
; }
521 Versions(const Versions
&);
522 Versions
& operator=(const Versions
&);
524 // The type of the list of version definitions.
525 typedef std::vector
<Verdef
*> Defs
;
527 // The type of the list of version references.
528 typedef std::vector
<Verneed
*> Needs
;
530 // Handle a symbol SYM defined with version VERSION.
532 add_def(const Symbol
* sym
, const char* version
, Stringpool::Key
);
534 // Add a reference to version NAME in file FILENAME.
536 add_need(Stringpool
*, const char* filename
, const char* name
,
539 // Get the dynamic object to use for SYM.
541 get_dynobj_for_sym(const Symbol_table
*, const Symbol
* sym
) const;
543 // Return the version index to use for SYM.
545 version_index(const Symbol_table
*, const Stringpool
*,
546 const Symbol
* sym
) const;
548 // We keep a hash table mapping canonicalized name/version pairs to
550 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Key
;
552 struct Version_table_hash
555 operator()(const Key
& k
) const
556 { return k
.first
+ k
.second
; }
559 struct Version_table_eq
562 operator()(const Key
& k1
, const Key
& k2
) const
563 { return k1
.first
== k2
.first
&& k1
.second
== k2
.second
; }
566 typedef Unordered_map
<Key
, Version_base
*, Version_table_hash
,
567 Version_table_eq
> Version_table
;
569 // The version definitions.
571 // The version references.
573 // The mapping from a canonicalized version/filename pair to a
574 // version index. The filename may be NULL.
575 Version_table version_table_
;
576 // Whether the version indexes have been set.
578 // Contents of --version-script, if passed, or NULL.
579 const Version_script_info
& version_script_
;
582 } // End namespace gold.
584 #endif // !defined(GOLD_DYNOBJ_H)