/* bfdlink.h -- header file for BFD link routines Copyright 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003 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_sec_merge, /* Discard local temporary symbols in SEC_MERGE sections. */ discard_none, /* Don't discard any locals. */ discard_l, /* Discard local temporary symbols. */ discard_all /* Discard all locals. */ }; /* Describes the type of hash table entry structure being used. Different hash table structure have different fields and so support different linking features. */ enum bfd_link_hash_table_type { bfd_link_generic_hash_table, bfd_link_elf_hash_table }; /* 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. */ }; enum bfd_link_common_skip_ar_aymbols { bfd_link_common_skip_none, bfd_link_common_skip_text, bfd_link_common_skip_data, bfd_link_common_skip_all }; /* 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 *und_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; /* The type of the link hash table. */ enum bfd_link_hash_table_type type; }; /* 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 (struct bfd_link_hash_table *, const char *, bfd_boolean create, bfd_boolean copy, bfd_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 (bfd *, struct bfd_link_info *, const char *, bfd_boolean, bfd_boolean, bfd_boolean); /* Traverse a link hash table. */ extern void bfd_link_hash_traverse (struct bfd_link_hash_table *, bfd_boolean (*) (struct bfd_link_hash_entry *, void *), void *); /* Add an entry to the undefs list. */ extern void bfd_link_add_undef (struct bfd_link_hash_table *, struct bfd_link_hash_entry *); struct bfd_sym_chain { struct bfd_sym_chain *next; const char *name; }; /* How to handle unresolved symbols. There are four possibilities which are enumerated below: */ enum report_method { /* This is the initial value when then link_info structure is created. It allows the various stages of the linker to determine whether they allowed to set the value. */ RM_NOT_YET_SET = 0, RM_IGNORE, RM_GENERATE_WARNING, RM_GENERATE_ERROR }; /* This structure holds all the information needed to communicate between BFD and the linker when doing a link. */ struct bfd_link_info { /* TRUE if BFD should generate a relocatable object file. */ unsigned int relocatable: 1; /* TRUE if BFD should generate relocation information in the final executable. */ unsigned int emitrelocations: 1; /* TRUE if BFD should generate a "task linked" object file, similar to relocatable but also with globals converted to statics. */ unsigned int task_link: 1; /* TRUE if BFD should generate a shared object. */ unsigned int shared: 1; /* TRUE if BFD should pre-bind symbols in a shared object. */ unsigned int symbolic: 1; /* TRUE if BFD should export all symbols in the dynamic symbol table of an executable, rather than only those used. */ unsigned int export_dynamic: 1; /* TRUE if shared objects should be linked directly, not shared. */ unsigned int static_link: 1; /* 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. */ unsigned int traditional_format: 1; /* TRUE if we want to produced optimized output files. This might need much more time and therefore must be explicitly selected. */ unsigned int optimize: 1; /* TRUE if ok to have multiple definition. */ unsigned int allow_multiple_definition: 1; /* TRUE if ok to have version with no definition. */ unsigned int allow_undefined_version: 1; /* TRUE if symbols should be retained in memory, FALSE if they should be freed and reread. */ unsigned int keep_memory: 1; /* TRUE if every symbol should be reported back via the notice callback. */ unsigned int notice_all: 1; /* TRUE if executable should not contain copy relocs. Setting this true may result in a non-sharable text segment. */ unsigned int nocopyreloc: 1; /* TRUE if the new ELF dynamic tags are enabled. */ unsigned int new_dtags: 1; /* TRUE if non-PLT relocs should be merged into one reloc section and sorted so that relocs against the same symbol come together. */ unsigned int combreloc: 1; /* TRUE if .eh_frame_hdr section and PT_GNU_EH_FRAME ELF segment should be created. */ unsigned int eh_frame_hdr: 1; /* TRUE if global symbols in discarded sections should be stripped. */ unsigned int strip_discarded: 1; /* TRUE if the final relax pass is needed. */ unsigned int need_relax_finalize: 1; /* TRUE if generating a position independent executable. */ unsigned int pie: 1; /* TRUE if generating an executable, position independent or not. */ unsigned int executable : 1; /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W|PF_X flags. */ unsigned int execstack: 1; /* TRUE if PT_GNU_STACK segment should be created with PF_R|PF_W flags. */ unsigned int noexecstack: 1; /* What to do with unresolved symbols in an object file. When producing static binaries the default is GENERATE_ERROR. When producing dynamic binaries the default is IGNORE. The assumption with dynamic binaries is that the reference will be resolved at load/execution time. */ enum report_method unresolved_syms_in_objects; /* What to do with unresolved symbols in a shared library. The same defaults apply. */ enum report_method unresolved_syms_in_shared_libs; /* Which symbols to strip. */ enum bfd_link_strip strip; /* Which local symbols to discard. */ enum bfd_link_discard discard; /* Criteria for skipping symbols when detemining whether to include an object from an archive. */ enum bfd_link_common_skip_ar_aymbols common_skip_ar_aymbols; /* Function callbacks. */ const struct bfd_link_callbacks *callbacks; /* 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; /* 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; /* 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; /* List of global symbol names that are starting points for marking sections against garbage collection. */ struct bfd_sym_chain *gc_sym_list; /* If a base output file is wanted, then this points to it */ void *base_file; /* The function to call when the executable or shared object is loaded. */ const char *init_function; /* The function to call when the executable or shared object is unloaded. */ const char *fini_function; /* Non-zero if auto-import thunks for DATA items in pei386 DLLs should be generated/linked against. Set to 1 if this feature is explicitly requested by the user, -1 if enabled by default. */ int pei386_auto_import; /* Non-zero if runtime relocs for DATA items with non-zero addends in pei386 DLLs should be generated. Set to 1 if this feature is explicitly requested by the user, -1 if enabled by default. */ int pei386_runtime_pseudo_reloc; /* How many spare .dynamic DT_NULL entries should be added? */ unsigned int spare_dynamic_tags; /* May be used to set DT_FLAGS for ELF. */ bfd_vma flags; /* May be used to set DT_FLAGS_1 for ELF. */ bfd_vma flags_1; }; /* 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. */ bfd_boolean (*add_archive_element) (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. */ bfd_boolean (*multiple_definition) (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. */ bfd_boolean (*multiple_common) (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 relocatable 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. */ bfd_boolean (*add_to_set) (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 relocatable file. NAME is the name of the symbol found. ABFD, SECTION and VALUE are the value of the symbol. */ bfd_boolean (*constructor) (struct bfd_link_info *, bfd_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. */ bfd_boolean (*warning) (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. FATAL indicates whether an undefined symbol is a fatal error or not. In some cases SECTION may be NULL. */ bfd_boolean (*undefined_symbol) (struct bfd_link_info *, const char *name, bfd *abfd, asection *section, bfd_vma address, bfd_boolean fatal); /* 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. */ bfd_boolean (*reloc_overflow) (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. */ bfd_boolean (*reloc_dangerous) (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. */ bfd_boolean (*unattached_reloc) (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. */ bfd_boolean (*notice) (struct bfd_link_info *, const char *name, bfd *abfd, asection *section, bfd_vma address); /* A function which is called for reporting a linker error. ID is the error identifier. The remaining input is the same as einfo () in ld. */ bfd_boolean (*error_handler) (int id, const char *fmt, ...); /* Identifiers of linker error messages used by error_handler. */ #define LD_DEFINITION_IN_DISCARDED_SECTION 1 }; /* 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_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 { /* Size of contents, or zero when contents size == size within output section. A non-zero value allows filling of the output section with an arbitrary repeated pattern. */ unsigned int size; /* Data to put into file. */ 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 (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. */ /* Glob pattern for a version. */ struct bfd_elf_version_expr { /* Next glob pattern for this version. */ struct bfd_elf_version_expr *next; /* Glob pattern. */ const char *pattern; /* NULL for a glob pattern, otherwise a straight symbol. */ const char *symbol; /* Defined by ".symver". */ unsigned int symver : 1; /* Defined by version script. */ unsigned int script : 1; /* Pattern type. */ #define BFD_ELF_VERSION_C_TYPE 1 #define BFD_ELF_VERSION_CXX_TYPE 2 #define BFD_ELF_VERSION_JAVA_TYPE 4 unsigned int mask : 3; }; struct bfd_elf_version_expr_head { /* List of all patterns, both wildcards and non-wildcards. */ struct bfd_elf_version_expr *list; /* Hash table for non-wildcards. */ void *htab; /* Remaining patterns. */ struct bfd_elf_version_expr *remaining; /* What kind of pattern types are present in list (bitmask). */ unsigned int mask; }; /* 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_head globals; /* Regular expressions for local symbols in this version. */ struct bfd_elf_version_expr_head 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; /* Matching hook. */ struct bfd_elf_version_expr *(*match) (struct bfd_elf_version_expr_head *head, struct bfd_elf_version_expr *prev, const char *sym); }; #endif