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Diffstat (limited to 'include/bfdlink.h')
| -rw-r--r-- | include/bfdlink.h | 520 |
1 files changed, 520 insertions, 0 deletions
diff --git a/include/bfdlink.h b/include/bfdlink.h new file mode 100644 index 0000000..a055fa0 --- /dev/null +++ b/include/bfdlink.h @@ -0,0 +1,520 @@ +/* bfdlink.h -- header file for BFD link routines + Copyright 1993, 94, 95, 96, 97, 1999 Free Software Foundation, Inc. + Written by Steve Chamberlain and Ian Lance Taylor, Cygnus Support. + +This file is part of BFD, the Binary File Descriptor library. + +This program is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or +(at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + +#ifndef BFDLINK_H +#define BFDLINK_H + +/* Which symbols to strip during a link. */ +enum bfd_link_strip +{ + strip_none, /* Don't strip any symbols. */ + strip_debugger, /* Strip debugging symbols. */ + strip_some, /* keep_hash is the list of symbols to keep. */ + strip_all /* Strip all symbols. */ +}; + +/* Which local symbols to discard during a link. This is irrelevant + if strip_all is used. */ +enum bfd_link_discard +{ + discard_none, /* Don't discard any locals. */ + discard_l, /* Discard local temporary symbols. */ + discard_all /* Discard all locals. */ +}; + +/* These are the possible types of an entry in the BFD link hash + table. */ + +enum bfd_link_hash_type +{ + bfd_link_hash_new, /* Symbol is new. */ + bfd_link_hash_undefined, /* Symbol seen before, but undefined. */ + bfd_link_hash_undefweak, /* Symbol is weak and undefined. */ + bfd_link_hash_defined, /* Symbol is defined. */ + bfd_link_hash_defweak, /* Symbol is weak and defined. */ + bfd_link_hash_common, /* Symbol is common. */ + bfd_link_hash_indirect, /* Symbol is an indirect link. */ + bfd_link_hash_warning /* Like indirect, but warn if referenced. */ +}; + +/* The linking routines use a hash table which uses this structure for + its elements. */ + +struct bfd_link_hash_entry +{ + /* Base hash table entry structure. */ + struct bfd_hash_entry root; + /* Type of this entry. */ + enum bfd_link_hash_type type; + + /* Undefined and common symbols are kept in a linked list through + this field. This field is not in the union because that would + force us to remove entries from the list when we changed their + type, which would force the list to be doubly linked, which would + waste more memory. When an undefined or common symbol is + created, it should be added to this list, the head of which is in + the link hash table itself. As symbols are defined, they need + not be removed from the list; anything which reads the list must + doublecheck the symbol type. + + Weak symbols are not kept on this list. + + Defined and defweak symbols use this field as a reference marker. + If the field is not NULL, or this structure is the tail of the + undefined symbol list, the symbol has been referenced. If the + symbol is undefined and becomes defined, this field will + automatically be non-NULL since the symbol will have been on the + undefined symbol list. */ + struct bfd_link_hash_entry *next; + /* A union of information depending upon the type. */ + union + { + /* Nothing is kept for bfd_hash_new. */ + /* bfd_link_hash_undefined, bfd_link_hash_undefweak. */ + struct + { + bfd *abfd; /* BFD symbol was found in. */ + } undef; + /* bfd_link_hash_defined, bfd_link_hash_defweak. */ + struct + { + bfd_vma value; /* Symbol value. */ + asection *section; /* Symbol section. */ + } def; + /* bfd_link_hash_indirect, bfd_link_hash_warning. */ + struct + { + struct bfd_link_hash_entry *link; /* Real symbol. */ + const char *warning; /* Warning (bfd_link_hash_warning only). */ + } i; + /* bfd_link_hash_common. */ + struct + { + /* The linker needs to know three things about common + symbols: the size, the alignment, and the section in + which the symbol should be placed. We store the size + here, and we allocate a small structure to hold the + section and the alignment. The alignment is stored as a + power of two. We don't store all the information + directly because we don't want to increase the size of + the union; this structure is a major space user in the + linker. */ + bfd_size_type size; /* Common symbol size. */ + struct bfd_link_hash_common_entry + { + unsigned int alignment_power; /* Alignment. */ + asection *section; /* Symbol section. */ + } *p; + } c; + } u; +}; + +/* This is the link hash table. It is a derived class of + bfd_hash_table. */ + +struct bfd_link_hash_table +{ + /* The hash table itself. */ + struct bfd_hash_table table; + /* The back end which created this hash table. This indicates the + type of the entries in the hash table, which is sometimes + important information when linking object files of different + types together. */ + const bfd_target *creator; + /* A linked list of undefined and common symbols, linked through the + next field in the bfd_link_hash_entry structure. */ + struct bfd_link_hash_entry *undefs; + /* Entries are added to the tail of the undefs list. */ + struct bfd_link_hash_entry *undefs_tail; +}; + +/* Look up an entry in a link hash table. If FOLLOW is true, this + follows bfd_link_hash_indirect and bfd_link_hash_warning links to + the real symbol. */ +extern struct bfd_link_hash_entry *bfd_link_hash_lookup + PARAMS ((struct bfd_link_hash_table *, const char *, boolean create, + boolean copy, boolean follow)); + +/* Look up an entry in the main linker hash table if the symbol might + be wrapped. This should only be used for references to an + undefined symbol, not for definitions of a symbol. */ + +extern struct bfd_link_hash_entry *bfd_wrapped_link_hash_lookup + PARAMS ((bfd *, struct bfd_link_info *, const char *, boolean, boolean, + boolean)); + +/* Traverse a link hash table. */ +extern void bfd_link_hash_traverse + PARAMS ((struct bfd_link_hash_table *, + boolean (*) (struct bfd_link_hash_entry *, PTR), + PTR)); + +/* Add an entry to the undefs list. */ +extern void bfd_link_add_undef + PARAMS ((struct bfd_link_hash_table *, struct bfd_link_hash_entry *)); + +/* This structure holds all the information needed to communicate + between BFD and the linker when doing a link. */ + +struct bfd_link_info +{ + /* Function callbacks. */ + const struct bfd_link_callbacks *callbacks; + /* true if BFD should generate a relocateable object file. */ + boolean relocateable; + /* true if BFD should generate a "task linked" object file, + similar to relocatable but also with globals converted to statics. */ + boolean task_link; + /* true if BFD should generate a shared object. */ + boolean shared; + /* true if BFD should pre-bind symbols in a shared object. */ + boolean symbolic; + /* true if shared objects should be linked directly, not shared. */ + boolean static_link; + /* true if the output file should be in a traditional format. This + is equivalent to the setting of the BFD_TRADITIONAL_FORMAT flag + on the output file, but may be checked when reading the input + files. */ + boolean traditional_format; + /* true if we want to produced optimized output files. This might + need much more time and therefore must be explicitly selected. */ + boolean optimize; + /* true if BFD should generate errors for undefined symbols + even if generating a shared object. */ + boolean no_undefined; + /* Which symbols to strip. */ + enum bfd_link_strip strip; + /* Which local symbols to discard. */ + enum bfd_link_discard discard; + /* true if symbols should be retained in memory, false if they + should be freed and reread. */ + boolean keep_memory; + /* The list of input BFD's involved in the link. These are chained + together via the link_next field. */ + bfd *input_bfds; + /* If a symbol should be created for each input BFD, this is section + where those symbols should be placed. It must be a section in + the output BFD. It may be NULL, in which case no such symbols + will be created. This is to support CREATE_OBJECT_SYMBOLS in the + linker command language. */ + asection *create_object_symbols_section; + /* Hash table handled by BFD. */ + struct bfd_link_hash_table *hash; + /* Hash table of symbols to keep. This is NULL unless strip is + strip_some. */ + struct bfd_hash_table *keep_hash; + /* true if every symbol should be reported back via the notice + callback. */ + boolean notice_all; + /* Hash table of symbols to report back via the notice callback. If + this is NULL, and notice_all is false, then no symbols are + reported back. */ + struct bfd_hash_table *notice_hash; + /* Hash table of symbols which are being wrapped (the --wrap linker + option). If this is NULL, no symbols are being wrapped. */ + struct bfd_hash_table *wrap_hash; + /* If a base output file is wanted, then this points to it */ + PTR base_file; + + /* If non-zero, specifies that branches which are problematic for the + MPC860 C0 (or earlier) should be checked for and modified. It gives the + number of bytes that should be checked at the end of each text page. */ + int mpc860c0; +}; + +/* This structures holds a set of callback functions. These are + called by the BFD linker routines. The first argument to each + callback function is the bfd_link_info structure being used. Each + function returns a boolean value. If the function returns false, + then the BFD function which called it will return with a failure + indication. */ + +struct bfd_link_callbacks +{ + /* A function which is called when an object is added from an + archive. ABFD is the archive element being added. NAME is the + name of the symbol which caused the archive element to be pulled + in. */ + boolean (*add_archive_element) PARAMS ((struct bfd_link_info *, + bfd *abfd, + const char *name)); + /* A function which is called when a symbol is found with multiple + definitions. NAME is the symbol which is defined multiple times. + OBFD is the old BFD, OSEC is the old section, OVAL is the old + value, NBFD is the new BFD, NSEC is the new section, and NVAL is + the new value. OBFD may be NULL. OSEC and NSEC may be + bfd_com_section or bfd_ind_section. */ + boolean (*multiple_definition) PARAMS ((struct bfd_link_info *, + const char *name, + bfd *obfd, + asection *osec, + bfd_vma oval, + bfd *nbfd, + asection *nsec, + bfd_vma nval)); + /* A function which is called when a common symbol is defined + multiple times. NAME is the symbol appearing multiple times. + OBFD is the BFD of the existing symbol; it may be NULL if this is + not known. OTYPE is the type of the existing symbol, which may + be bfd_link_hash_defined, bfd_link_hash_defweak, + bfd_link_hash_common, or bfd_link_hash_indirect. If OTYPE is + bfd_link_hash_common, OSIZE is the size of the existing symbol. + NBFD is the BFD of the new symbol. NTYPE is the type of the new + symbol, one of bfd_link_hash_defined, bfd_link_hash_common, or + bfd_link_hash_indirect. If NTYPE is bfd_link_hash_common, NSIZE + is the size of the new symbol. */ + boolean (*multiple_common) PARAMS ((struct bfd_link_info *, + const char *name, + bfd *obfd, + enum bfd_link_hash_type otype, + bfd_vma osize, + bfd *nbfd, + enum bfd_link_hash_type ntype, + bfd_vma nsize)); + /* A function which is called to add a symbol to a set. ENTRY is + the link hash table entry for the set itself (e.g., + __CTOR_LIST__). RELOC is the relocation to use for an entry in + the set when generating a relocateable file, and is also used to + get the size of the entry when generating an executable file. + ABFD, SEC and VALUE identify the value to add to the set. */ + boolean (*add_to_set) PARAMS ((struct bfd_link_info *, + struct bfd_link_hash_entry *entry, + bfd_reloc_code_real_type reloc, + bfd *abfd, asection *sec, bfd_vma value)); + /* A function which is called when the name of a g++ constructor or + destructor is found. This is only called by some object file + formats. CONSTRUCTOR is true for a constructor, false for a + destructor. This will use BFD_RELOC_CTOR when generating a + relocateable file. NAME is the name of the symbol found. ABFD, + SECTION and VALUE are the value of the symbol. */ + boolean (*constructor) PARAMS ((struct bfd_link_info *, + boolean constructor, + const char *name, bfd *abfd, asection *sec, + bfd_vma value)); + /* A function which is called to issue a linker warning. For + example, this is called when there is a reference to a warning + symbol. WARNING is the warning to be issued. SYMBOL is the name + of the symbol which triggered the warning; it may be NULL if + there is none. ABFD, SECTION and ADDRESS identify the location + which trigerred the warning; either ABFD or SECTION or both may + be NULL if the location is not known. */ + boolean (*warning) PARAMS ((struct bfd_link_info *, + const char *warning, const char *symbol, + bfd *abfd, asection *section, + bfd_vma address)); + /* A function which is called when a relocation is attempted against + an undefined symbol. NAME is the symbol which is undefined. + ABFD, SECTION and ADDRESS identify the location from which the + reference is made. In some cases SECTION may be NULL. */ + boolean (*undefined_symbol) PARAMS ((struct bfd_link_info *, + const char *name, bfd *abfd, + asection *section, bfd_vma address)); + /* A function which is called when a reloc overflow occurs. NAME is + the name of the symbol or section the reloc is against, + RELOC_NAME is the name of the relocation, and ADDEND is any + addend that is used. ABFD, SECTION and ADDRESS identify the + location at which the overflow occurs; if this is the result of a + bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then + ABFD will be NULL. */ + boolean (*reloc_overflow) PARAMS ((struct bfd_link_info *, + const char *name, + const char *reloc_name, bfd_vma addend, + bfd *abfd, asection *section, + bfd_vma address)); + /* A function which is called when a dangerous reloc is performed. + The canonical example is an a29k IHCONST reloc which does not + follow an IHIHALF reloc. MESSAGE is an appropriate message. + ABFD, SECTION and ADDRESS identify the location at which the + problem occurred; if this is the result of a + bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then + ABFD will be NULL. */ + boolean (*reloc_dangerous) PARAMS ((struct bfd_link_info *, + const char *message, + bfd *abfd, asection *section, + bfd_vma address)); + /* A function which is called when a reloc is found to be attached + to a symbol which is not being written out. NAME is the name of + the symbol. ABFD, SECTION and ADDRESS identify the location of + the reloc; if this is the result of a + bfd_section_reloc_link_order or bfd_symbol_reloc_link_order, then + ABFD will be NULL. */ + boolean (*unattached_reloc) PARAMS ((struct bfd_link_info *, + const char *name, + bfd *abfd, asection *section, + bfd_vma address)); + /* A function which is called when a symbol in notice_hash is + defined or referenced. NAME is the symbol. ABFD, SECTION and + ADDRESS are the value of the symbol. If SECTION is + bfd_und_section, this is a reference. */ + boolean (*notice) PARAMS ((struct bfd_link_info *, const char *name, + bfd *abfd, asection *section, bfd_vma address)); +}; + +/* The linker builds link_order structures which tell the code how to + include input data in the output file. */ + +/* These are the types of link_order structures. */ + +enum bfd_link_order_type +{ + bfd_undefined_link_order, /* Undefined. */ + bfd_indirect_link_order, /* Built from a section. */ + bfd_fill_link_order, /* Fill with a 16 bit constant. */ + bfd_data_link_order, /* Set to explicit data. */ + bfd_section_reloc_link_order, /* Relocate against a section. */ + bfd_symbol_reloc_link_order /* Relocate against a symbol. */ +}; + +/* This is the link_order structure itself. These form a chain + attached to the section whose contents they are describing. */ + +struct bfd_link_order +{ + /* Next link_order in chain. */ + struct bfd_link_order *next; + /* Type of link_order. */ + enum bfd_link_order_type type; + /* Offset within output section. */ + bfd_vma offset; + /* Size within output section. */ + bfd_size_type size; + /* Type specific information. */ + union + { + struct + { + /* Section to include. If this is used, then + section->output_section must be the section the + link_order is attached to, section->output_offset must + equal the link_order offset field, and section->_raw_size + must equal the link_order size field. Maybe these + restrictions should be relaxed someday. */ + asection *section; + } indirect; + struct + { + /* Value to fill with. */ + unsigned int value; + } fill; + struct + { + /* Data to put into file. The size field gives the number + of bytes which this field points to. */ + bfd_byte *contents; + } data; + struct + { + /* Description of reloc to generate. Used for + bfd_section_reloc_link_order and + bfd_symbol_reloc_link_order. */ + struct bfd_link_order_reloc *p; + } reloc; + } u; +}; + +/* A linker order of type bfd_section_reloc_link_order or + bfd_symbol_reloc_link_order means to create a reloc against a + section or symbol, respectively. This is used to implement -Ur to + generate relocs for the constructor tables. The + bfd_link_order_reloc structure describes the reloc that BFD should + create. It is similar to a arelent, but I didn't use arelent + because the linker does not know anything about most symbols, and + any asymbol structure it creates will be partially meaningless. + This information could logically be in the bfd_link_order struct, + but I didn't want to waste the space since these types of relocs + are relatively rare. */ + +struct bfd_link_order_reloc +{ + /* Reloc type. */ + bfd_reloc_code_real_type reloc; + + union + { + /* For type bfd_section_reloc_link_order, this is the section + the reloc should be against. This must be a section in the + output BFD, not any of the input BFDs. */ + asection *section; + /* For type bfd_symbol_reloc_link_order, this is the name of the + symbol the reloc should be against. */ + const char *name; + } u; + + /* Addend to use. The object file should contain zero. The BFD + backend is responsible for filling in the contents of the object + file correctly. For some object file formats (e.g., COFF) the + addend must be stored into in the object file, and for some + (e.g., SPARC a.out) it is kept in the reloc. */ + bfd_vma addend; +}; + +/* Allocate a new link_order for a section. */ +extern struct bfd_link_order *bfd_new_link_order PARAMS ((bfd *, asection *)); + +/* These structures are used to describe version information for the + ELF linker. These structures could be manipulated entirely inside + BFD, but it would be a pain. Instead, the regular linker sets up + these structures, and then passes them into BFD. */ + +/* Regular expressions for a version. */ + +struct bfd_elf_version_expr +{ + /* Next regular expression for this version. */ + struct bfd_elf_version_expr *next; + /* Regular expression. */ + const char *pattern; + /* Matching function. */ + int (*match) PARAMS((struct bfd_elf_version_expr *, const char *)); +}; + +/* Version dependencies. */ + +struct bfd_elf_version_deps +{ + /* Next dependency for this version. */ + struct bfd_elf_version_deps *next; + /* The version which this version depends upon. */ + struct bfd_elf_version_tree *version_needed; +}; + +/* A node in the version tree. */ + +struct bfd_elf_version_tree +{ + /* Next version. */ + struct bfd_elf_version_tree *next; + /* Name of this version. */ + const char *name; + /* Version number. */ + unsigned int vernum; + /* Regular expressions for global symbols in this version. */ + struct bfd_elf_version_expr *globals; + /* Regular expressions for local symbols in this version. */ + struct bfd_elf_version_expr *locals; + /* List of versions which this version depends upon. */ + struct bfd_elf_version_deps *deps; + /* Index of the version name. This is used within BFD. */ + unsigned int name_indx; + /* Whether this version tree was used. This is used within BFD. */ + int used; +}; + +#endif |