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 // 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 Sized_dynobj(const std::string
& name
, Input_file
* input_file
, off_t offset
,
160 const typename
elfcpp::Ehdr
<size
, big_endian
>&);
162 // Set up the object file based on the ELF header.
164 setup(const typename
elfcpp::Ehdr
<size
, big_endian
>&);
168 do_read_symbols(Read_symbols_data
*);
170 // Lay out the input sections.
172 do_layout(Symbol_table
*, Layout
*, Read_symbols_data
*);
174 // Add the symbols to the symbol table.
176 do_add_symbols(Symbol_table
*, Read_symbols_data
*);
178 // Get the name of a section.
180 do_section_name(unsigned int shndx
)
181 { return this->elf_file_
.section_name(shndx
); }
183 // Return a view of the contents of a section. Set *PLEN to the
186 do_section_contents(unsigned int shndx
)
187 { return this->elf_file_
.section_contents(shndx
); }
189 // Return section flags.
191 do_section_flags(unsigned int shndx
)
192 { return this->elf_file_
.section_flags(shndx
); }
194 // Return section type.
196 do_section_type(unsigned int shndx
)
197 { return this->elf_file_
.section_type(shndx
); }
199 // Return the section link field.
201 do_section_link(unsigned int shndx
)
202 { return this->elf_file_
.section_link(shndx
); }
204 // Return the section link field.
206 do_section_info(unsigned int shndx
)
207 { return this->elf_file_
.section_info(shndx
); }
211 typedef Sized_dynobj
<size
, big_endian
> This
;
212 static const int shdr_size
= elfcpp::Elf_sizes
<size
>::shdr_size
;
213 static const int sym_size
= elfcpp::Elf_sizes
<size
>::sym_size
;
214 static const int dyn_size
= elfcpp::Elf_sizes
<size
>::dyn_size
;
215 typedef elfcpp::Shdr
<size
, big_endian
> Shdr
;
216 typedef elfcpp::Dyn
<size
, big_endian
> Dyn
;
218 // Find the dynamic symbol table and the version sections, given the
221 find_dynsym_sections(const unsigned char* pshdrs
,
222 unsigned int* pdynshm_shndx
,
223 unsigned int* pversym_shndx
,
224 unsigned int* pverdef_shndx
,
225 unsigned int* pverneed_shndx
,
226 unsigned int* pdynamic_shndx
);
228 // Read the dynamic symbol section SHNDX.
230 read_dynsym_section(const unsigned char* pshdrs
, unsigned int shndx
,
231 elfcpp::SHT type
, unsigned int link
,
232 File_view
** view
, off_t
* view_size
,
233 unsigned int* view_info
);
235 // Read the dynamic tags.
237 read_dynamic(const unsigned char* pshdrs
, unsigned int dynamic_shndx
,
238 unsigned int strtab_shndx
, const unsigned char* strtabu
,
241 // Mapping from version number to version name.
242 typedef std::vector
<const char*> Version_map
;
244 // Create the version map.
246 make_version_map(Read_symbols_data
* sd
, Version_map
*) const;
248 // Add version definitions to the version map.
250 make_verdef_map(Read_symbols_data
* sd
, Version_map
*) const;
252 // Add version references to the version map.
254 make_verneed_map(Read_symbols_data
* sd
, Version_map
*) const;
256 // Add an entry to the version map.
258 set_version_map(Version_map
*, unsigned int ndx
, const char* name
) const;
260 // General access to the ELF file.
261 elfcpp::Elf_file
<size
, big_endian
, Object
> elf_file_
;
264 // A base class for Verdef and Verneed_version which just handles the
265 // version index which will be stored in the SHT_GNU_versym section.
278 // Return the version index.
282 gold_assert(this->index_
!= -1U);
286 // Set the version index.
288 set_index(unsigned int index
)
290 gold_assert(this->index_
== -1U);
291 this->index_
= index
;
294 // Clear the weak flag in a version definition.
299 Version_base(const Version_base
&);
300 Version_base
& operator=(const Version_base
&);
302 // The index of the version definition or reference.
306 // This class handles a version being defined in the file we are
309 class Verdef
: public Version_base
312 Verdef(const char* name
, bool is_base
, bool is_weak
, bool is_symbol_created
)
313 : name_(name
), deps_(), is_base_(is_base
), is_weak_(is_weak
),
314 is_symbol_created_(is_symbol_created
)
317 // Return the version name.
320 { return this->name_
; }
322 // Return the number of dependencies.
324 count_dependencies() const
325 { return this->deps_
.size(); }
327 // Add a dependency to this version. The NAME should be
328 // canonicalized in the dynamic Stringpool.
330 add_dependency(const char* name
)
331 { this->deps_
.push_back(name
); }
333 // Return whether this definition is weak.
336 { return this->is_weak_
; }
338 // Clear the weak flag.
341 { this->is_weak_
= false; }
343 // Return whether a version symbol has been created for this
346 is_symbol_created() const
347 { return this->is_symbol_created_
; }
349 // Write contents to buffer.
350 template<int size
, bool big_endian
>
352 write(const Stringpool
*, bool is_last
, unsigned char*
353 ACCEPT_SIZE_ENDIAN
) const;
356 Verdef(const Verdef
&);
357 Verdef
& operator=(const Verdef
&);
359 // The type of the list of version dependencies. Each dependency
360 // should be canonicalized in the dynamic Stringpool.
361 typedef std::vector
<const char*> Deps
;
363 // The name of this version. This should be canonicalized in the
364 // dynamic Stringpool.
366 // A list of other versions which this version depends upon.
368 // Whether this is the base version.
370 // Whether this version is weak.
372 // Whether a version symbol has been created.
373 bool is_symbol_created_
;
376 // A referened version. This will be associated with a filename by
379 class Verneed_version
: public Version_base
382 Verneed_version(const char* version
)
386 // Return the version name.
389 { return this->version_
; }
391 // Clear the weak flag. This is invalid for a reference.
394 { gold_unreachable(); }
397 Verneed_version(const Verneed_version
&);
398 Verneed_version
& operator=(const Verneed_version
&);
400 const char* version_
;
403 // Version references in a single dynamic object.
408 Verneed(const char* filename
)
409 : filename_(filename
), need_versions_()
414 // Return the file name.
417 { return this->filename_
; }
419 // Return the number of versions.
421 count_versions() const
422 { return this->need_versions_
.size(); }
424 // Add a version name. The name should be canonicalized in the
425 // dynamic Stringpool. If the name is already present, this does
428 add_name(const char* name
);
430 // Set the version indexes, starting at INDEX. Return the updated
433 finalize(unsigned int index
);
435 // Write contents to buffer.
436 template<int size
, bool big_endian
>
438 write(const Stringpool
*, bool is_last
, unsigned char*
439 ACCEPT_SIZE_ENDIAN
) const;
442 Verneed(const Verneed
&);
443 Verneed
& operator=(const Verneed
&);
445 // The type of the list of version names. Each name should be
446 // canonicalized in the dynamic Stringpool.
447 typedef std::vector
<Verneed_version
*> Need_versions
;
449 // The filename of the dynamic object. This should be
450 // canonicalized in the dynamic Stringpool.
451 const char* filename_
;
452 // The list of version names.
453 Need_versions need_versions_
;
456 // This class handles version definitions and references which go into
463 : defs_(), needs_(), version_table_(), is_finalized_(false)
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(const Target
*, 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;
517 // The type of the list of version definitions.
518 typedef std::vector
<Verdef
*> Defs
;
520 // The type of the list of version references.
521 typedef std::vector
<Verneed
*> Needs
;
523 // Handle a symbol SYM defined with version VERSION.
525 add_def(const Symbol
* sym
, const char* version
, Stringpool::Key
);
527 // Add a reference to version NAME in file FILENAME.
529 add_need(Stringpool
*, const char* filename
, const char* name
,
532 // Get the dynamic object to use for SYM.
534 get_dynobj_for_sym(const Symbol_table
*, const Symbol
* sym
) const;
536 // Return the version index to use for SYM.
538 version_index(const Symbol_table
*, const Stringpool
*,
539 const Symbol
* sym
) const;
541 // We keep a hash table mapping canonicalized name/version pairs to
543 typedef std::pair
<Stringpool::Key
, Stringpool::Key
> Key
;
545 struct Version_table_hash
548 operator()(const Key
& k
) const
549 { return k
.first
+ k
.second
; }
552 struct Version_table_eq
555 operator()(const Key
& k1
, const Key
& k2
) const
556 { return k1
.first
== k2
.first
&& k1
.second
== k2
.second
; }
559 typedef Unordered_map
<Key
, Version_base
*, Version_table_hash
,
560 Version_table_eq
> Version_table
;
562 // The version definitions.
564 // The version references.
566 // The mapping from a canonicalized version/filename pair to a
567 // version index. The filename may be NULL.
568 Version_table version_table_
;
569 // Whether the version indexes have been set.
573 } // End namespace gold.
575 #endif // !defined(GOLD_DYNOBJ_H)