This is bfd.info, produced by makeinfo version 4.0 from bfd.texinfo. START-INFO-DIR-ENTRY * Bfd: (bfd). The Binary File Descriptor library. END-INFO-DIR-ENTRY This file documents the BFD library. Copyright (C) 1991, 2000 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".  File: bfd.info, Node: coff, Next: elf, Prev: aout, Up: BFD back ends coff backends ============= BFD supports a number of different flavours of coff format. The major differences between formats are the sizes and alignments of fields in structures on disk, and the occasional extra field. Coff in all its varieties is implemented with a few common files and a number of implementation specific files. For example, The 88k bcs coff format is implemented in the file `coff-m88k.c'. This file `#include's `coff/m88k.h' which defines the external structure of the coff format for the 88k, and `coff/internal.h' which defines the internal structure. `coff-m88k.c' also defines the relocations used by the 88k format *Note Relocations::. The Intel i960 processor version of coff is implemented in `coff-i960.c'. This file has the same structure as `coff-m88k.c', except that it includes `coff/i960.h' rather than `coff-m88k.h'. Porting to a new version of coff -------------------------------- The recommended method is to select from the existing implementations the version of coff which is most like the one you want to use. For example, we'll say that i386 coff is the one you select, and that your coff flavour is called foo. Copy `i386coff.c' to `foocoff.c', copy `../include/coff/i386.h' to `../include/coff/foo.h', and add the lines to `targets.c' and `Makefile.in' so that your new back end is used. Alter the shapes of the structures in `../include/coff/foo.h' so that they match what you need. You will probably also have to add `#ifdef's to the code in `coff/internal.h' and `coffcode.h' if your version of coff is too wild. You can verify that your new BFD backend works quite simply by building `objdump' from the `binutils' directory, and making sure that its version of what's going on and your host system's idea (assuming it has the pretty standard coff dump utility, usually called `att-dump' or just `dump') are the same. Then clean up your code, and send what you've done to Cygnus. Then your stuff will be in the next release, and you won't have to keep integrating it. How the coff backend works -------------------------- File layout ........... The Coff backend is split into generic routines that are applicable to any Coff target and routines that are specific to a particular target. The target-specific routines are further split into ones which are basically the same for all Coff targets except that they use the external symbol format or use different values for certain constants. The generic routines are in `coffgen.c'. These routines work for any Coff target. They use some hooks into the target specific code; the hooks are in a `bfd_coff_backend_data' structure, one of which exists for each target. The essentially similar target-specific routines are in `coffcode.h'. This header file includes executable C code. The various Coff targets first include the appropriate Coff header file, make any special defines that are needed, and then include `coffcode.h'. Some of the Coff targets then also have additional routines in the target source file itself. For example, `coff-i960.c' includes `coff/internal.h' and `coff/i960.h'. It then defines a few constants, such as `I960', and includes `coffcode.h'. Since the i960 has complex relocation types, `coff-i960.c' also includes some code to manipulate the i960 relocs. This code is not in `coffcode.h' because it would not be used by any other target. Bit twiddling ............. Each flavour of coff supported in BFD has its own header file describing the external layout of the structures. There is also an internal description of the coff layout, in `coff/internal.h'. A major function of the coff backend is swapping the bytes and twiddling the bits to translate the external form of the structures into the normal internal form. This is all performed in the `bfd_swap'_thing_direction routines. Some elements are different sizes between different versions of coff; it is the duty of the coff version specific include file to override the definitions of various packing routines in `coffcode.h'. E.g., the size of line number entry in coff is sometimes 16 bits, and sometimes 32 bits. `#define'ing `PUT_LNSZ_LNNO' and `GET_LNSZ_LNNO' will select the correct one. No doubt, some day someone will find a version of coff which has a varying field size not catered to at the moment. To port BFD, that person will have to add more `#defines'. Three of the bit twiddling routines are exported to `gdb'; `coff_swap_aux_in', `coff_swap_sym_in' and `coff_swap_lineno_in'. `GDB' reads the symbol table on its own, but uses BFD to fix things up. More of the bit twiddlers are exported for `gas'; `coff_swap_aux_out', `coff_swap_sym_out', `coff_swap_lineno_out', `coff_swap_reloc_out', `coff_swap_filehdr_out', `coff_swap_aouthdr_out', `coff_swap_scnhdr_out'. `Gas' currently keeps track of all the symbol table and reloc drudgery itself, thereby saving the internal BFD overhead, but uses BFD to swap things on the way out, making cross ports much safer. Doing so also allows BFD (and thus the linker) to use the same header files as `gas', which makes one avenue to disaster disappear. Symbol reading .............. The simple canonical form for symbols used by BFD is not rich enough to keep all the information available in a coff symbol table. The back end gets around this problem by keeping the original symbol table around, "behind the scenes". When a symbol table is requested (through a call to `bfd_canonicalize_symtab'), a request gets through to `coff_get_normalized_symtab'. This reads the symbol table from the coff file and swaps all the structures inside into the internal form. It also fixes up all the pointers in the table (represented in the file by offsets from the first symbol in the table) into physical pointers to elements in the new internal table. This involves some work since the meanings of fields change depending upon context: a field that is a pointer to another structure in the symbol table at one moment may be the size in bytes of a structure at the next. Another pass is made over the table. All symbols which mark file names (`C_FILE' symbols) are modified so that the internal string points to the value in the auxent (the real filename) rather than the normal text associated with the symbol (`".file"'). At this time the symbol names are moved around. Coff stores all symbols less than nine characters long physically within the symbol table; longer strings are kept at the end of the file in the string table. This pass moves all strings into memory and replaces them with pointers to the strings. The symbol table is massaged once again, this time to create the canonical table used by the BFD application. Each symbol is inspected in turn, and a decision made (using the `sclass' field) about the various flags to set in the `asymbol'. *Note Symbols::. The generated canonical table shares strings with the hidden internal symbol table. Any linenumbers are read from the coff file too, and attached to the symbols which own the functions the linenumbers belong to. Symbol writing .............. Writing a symbol to a coff file which didn't come from a coff file will lose any debugging information. The `asymbol' structure remembers the BFD from which the symbol was taken, and on output the back end makes sure that the same destination target as source target is present. When the symbols have come from a coff file then all the debugging information is preserved. Symbol tables are provided for writing to the back end in a vector of pointers to pointers. This allows applications like the linker to accumulate and output large symbol tables without having to do too much byte copying. This function runs through the provided symbol table and patches each symbol marked as a file place holder (`C_FILE') to point to the next file place holder in the list. It also marks each `offset' field in the list with the offset from the first symbol of the current symbol. Another function of this procedure is to turn the canonical value form of BFD into the form used by coff. Internally, BFD expects symbol values to be offsets from a section base; so a symbol physically at 0x120, but in a section starting at 0x100, would have the value 0x20. Coff expects symbols to contain their final value, so symbols have their values changed at this point to reflect their sum with their owning section. This transformation uses the `output_section' field of the `asymbol''s `asection' *Note Sections::. * `coff_mangle_symbols' This routine runs though the provided symbol table and uses the offsets generated by the previous pass and the pointers generated when the symbol table was read in to create the structured hierachy required by coff. It changes each pointer to a symbol into the index into the symbol table of the asymbol. * `coff_write_symbols' This routine runs through the symbol table and patches up the symbols from their internal form into the coff way, calls the bit twiddlers, and writes out the table to the file. `coff_symbol_type' .................. *Description* The hidden information for an `asymbol' is described in a `combined_entry_type': typedef struct coff_ptr_struct { /* Remembers the offset from the first symbol in the file for this symbol. Generated by coff_renumber_symbols. */ unsigned int offset; /* Should the value of this symbol be renumbered. Used for XCOFF C_BSTAT symbols. Set by coff_slurp_symbol_table. */ unsigned int fix_value : 1; /* Should the tag field of this symbol be renumbered. Created by coff_pointerize_aux. */ unsigned int fix_tag : 1; /* Should the endidx field of this symbol be renumbered. Created by coff_pointerize_aux. */ unsigned int fix_end : 1; /* Should the x_csect.x_scnlen field be renumbered. Created by coff_pointerize_aux. */ unsigned int fix_scnlen : 1; /* Fix up an XCOFF C_BINCL/C_EINCL symbol. The value is the index into the line number entries. Set by coff_slurp_symbol_table. */ unsigned int fix_line : 1; /* The container for the symbol structure as read and translated from the file. */ union { union internal_auxent auxent; struct internal_syment syment; } u; } combined_entry_type; /* Each canonical asymbol really looks like this: */ typedef struct coff_symbol_struct { /* The actual symbol which the rest of BFD works with */ asymbol symbol; /* A pointer to the hidden information for this symbol */ combined_entry_type *native; /* A pointer to the linenumber information for this symbol */ struct lineno_cache_entry *lineno; /* Have the line numbers been relocated yet ? */ boolean done_lineno; } coff_symbol_type; `bfd_coff_backend_data' ....................... /* COFF symbol classifications. */ enum coff_symbol_classification { /* Global symbol. */ COFF_SYMBOL_GLOBAL, /* Common symbol. */ COFF_SYMBOL_COMMON, /* Undefined symbol. */ COFF_SYMBOL_UNDEFINED, /* Local symbol. */ COFF_SYMBOL_LOCAL, /* PE section symbol. */ COFF_SYMBOL_PE_SECTION }; Special entry points for gdb to swap in coff symbol table parts: typedef struct { void (*_bfd_coff_swap_aux_in) PARAMS (( bfd *abfd, PTR ext, int type, int class, int indaux, int numaux, PTR in)); void (*_bfd_coff_swap_sym_in) PARAMS (( bfd *abfd , PTR ext, PTR in)); void (*_bfd_coff_swap_lineno_in) PARAMS (( bfd *abfd, PTR ext, PTR in)); Special entry points for gas to swap out coff parts: unsigned int (*_bfd_coff_swap_aux_out) PARAMS (( bfd *abfd, PTR in, int type, int class, int indaux, int numaux, PTR ext)); unsigned int (*_bfd_coff_swap_sym_out) PARAMS (( bfd *abfd, PTR in, PTR ext)); unsigned int (*_bfd_coff_swap_lineno_out) PARAMS (( bfd *abfd, PTR in, PTR ext)); unsigned int (*_bfd_coff_swap_reloc_out) PARAMS (( bfd *abfd, PTR src, PTR dst)); unsigned int (*_bfd_coff_swap_filehdr_out) PARAMS (( bfd *abfd, PTR in, PTR out)); unsigned int (*_bfd_coff_swap_aouthdr_out) PARAMS (( bfd *abfd, PTR in, PTR out)); unsigned int (*_bfd_coff_swap_scnhdr_out) PARAMS (( bfd *abfd, PTR in, PTR out)); Special entry points for generic COFF routines to call target dependent COFF routines: unsigned int _bfd_filhsz; unsigned int _bfd_aoutsz; unsigned int _bfd_scnhsz; unsigned int _bfd_symesz; unsigned int _bfd_auxesz; unsigned int _bfd_relsz; unsigned int _bfd_linesz; unsigned int _bfd_filnmlen; boolean _bfd_coff_long_filenames; boolean _bfd_coff_long_section_names; unsigned int _bfd_coff_default_section_alignment_power; boolean _bfd_coff_force_symnames_in_strings; unsigned int _bfd_coff_debug_string_prefix_length; void (*_bfd_coff_swap_filehdr_in) PARAMS (( bfd *abfd, PTR ext, PTR in)); void (*_bfd_coff_swap_aouthdr_in) PARAMS (( bfd *abfd, PTR ext, PTR in)); void (*_bfd_coff_swap_scnhdr_in) PARAMS (( bfd *abfd, PTR ext, PTR in)); void (*_bfd_coff_swap_reloc_in) PARAMS (( bfd *abfd, PTR ext, PTR in)); boolean (*_bfd_coff_bad_format_hook) PARAMS (( bfd *abfd, PTR internal_filehdr)); boolean (*_bfd_coff_set_arch_mach_hook) PARAMS (( bfd *abfd, PTR internal_filehdr)); PTR (*_bfd_coff_mkobject_hook) PARAMS (( bfd *abfd, PTR internal_filehdr, PTR internal_aouthdr)); flagword (*_bfd_styp_to_sec_flags_hook) PARAMS (( bfd *abfd, PTR internal_scnhdr, const char *name, asection *section)); void (*_bfd_set_alignment_hook) PARAMS (( bfd *abfd, asection *sec, PTR internal_scnhdr)); boolean (*_bfd_coff_slurp_symbol_table) PARAMS (( bfd *abfd)); boolean (*_bfd_coff_symname_in_debug) PARAMS (( bfd *abfd, struct internal_syment *sym)); boolean (*_bfd_coff_pointerize_aux_hook) PARAMS (( bfd *abfd, combined_entry_type *table_base, combined_entry_type *symbol, unsigned int indaux, combined_entry_type *aux)); boolean (*_bfd_coff_print_aux) PARAMS (( bfd *abfd, FILE *file, combined_entry_type *table_base, combined_entry_type *symbol, combined_entry_type *aux, unsigned int indaux)); void (*_bfd_coff_reloc16_extra_cases) PARAMS (( bfd *abfd, struct bfd_link_info *link_info, struct bfd_link_order *link_order, arelent *reloc, bfd_byte *data, unsigned int *src_ptr, unsigned int *dst_ptr)); int (*_bfd_coff_reloc16_estimate) PARAMS (( bfd *abfd, asection *input_section, arelent *r, unsigned int shrink, struct bfd_link_info *link_info)); enum coff_symbol_classification (*_bfd_coff_classify_symbol) PARAMS (( bfd *abfd, struct internal_syment *)); boolean (*_bfd_coff_compute_section_file_positions) PARAMS (( bfd *abfd)); boolean (*_bfd_coff_start_final_link) PARAMS (( bfd *output_bfd, struct bfd_link_info *info)); boolean (*_bfd_coff_relocate_section) PARAMS (( bfd *output_bfd, struct bfd_link_info *info, bfd *input_bfd, asection *input_section, bfd_byte *contents, struct internal_reloc *relocs, struct internal_syment *syms, asection **sections)); reloc_howto_type *(*_bfd_coff_rtype_to_howto) PARAMS (( bfd *abfd, asection *sec, struct internal_reloc *rel, struct coff_link_hash_entry *h, struct internal_syment *sym, bfd_vma *addendp)); boolean (*_bfd_coff_adjust_symndx) PARAMS (( bfd *obfd, struct bfd_link_info *info, bfd *ibfd, asection *sec, struct internal_reloc *reloc, boolean *adjustedp)); boolean (*_bfd_coff_link_add_one_symbol) PARAMS (( struct bfd_link_info *info, bfd *abfd, const char *name, flagword flags, asection *section, bfd_vma value, const char *string, boolean copy, boolean collect, struct bfd_link_hash_entry **hashp)); boolean (*_bfd_coff_link_output_has_begun) PARAMS (( bfd * abfd, struct coff_final_link_info * pfinfo)); boolean (*_bfd_coff_final_link_postscript) PARAMS (( bfd * abfd, struct coff_final_link_info * pfinfo)); } bfd_coff_backend_data; #define coff_backend_info(abfd) ((bfd_coff_backend_data *) (abfd)->xvec->backend_data) #define bfd_coff_swap_aux_in(a,e,t,c,ind,num,i) \ ((coff_backend_info (a)->_bfd_coff_swap_aux_in) (a,e,t,c,ind,num,i)) #define bfd_coff_swap_sym_in(a,e,i) \ ((coff_backend_info (a)->_bfd_coff_swap_sym_in) (a,e,i)) #define bfd_coff_swap_lineno_in(a,e,i) \ ((coff_backend_info ( a)->_bfd_coff_swap_lineno_in) (a,e,i)) #define bfd_coff_swap_reloc_out(abfd, i, o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_reloc_out) (abfd, i, o)) #define bfd_coff_swap_lineno_out(abfd, i, o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_lineno_out) (abfd, i, o)) #define bfd_coff_swap_aux_out(a,i,t,c,ind,num,o) \ ((coff_backend_info (a)->_bfd_coff_swap_aux_out) (a,i,t,c,ind,num,o)) #define bfd_coff_swap_sym_out(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_sym_out) (abfd, i, o)) #define bfd_coff_swap_scnhdr_out(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_scnhdr_out) (abfd, i, o)) #define bfd_coff_swap_filehdr_out(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_filehdr_out) (abfd, i, o)) #define bfd_coff_swap_aouthdr_out(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_aouthdr_out) (abfd, i, o)) #define bfd_coff_filhsz(abfd) (coff_backend_info (abfd)->_bfd_filhsz) #define bfd_coff_aoutsz(abfd) (coff_backend_info (abfd)->_bfd_aoutsz) #define bfd_coff_scnhsz(abfd) (coff_backend_info (abfd)->_bfd_scnhsz) #define bfd_coff_symesz(abfd) (coff_backend_info (abfd)->_bfd_symesz) #define bfd_coff_auxesz(abfd) (coff_backend_info (abfd)->_bfd_auxesz) #define bfd_coff_relsz(abfd) (coff_backend_info (abfd)->_bfd_relsz) #define bfd_coff_linesz(abfd) (coff_backend_info (abfd)->_bfd_linesz) #define bfd_coff_filnmlen(abfd) (coff_backend_info (abfd)->_bfd_filnmlen) #define bfd_coff_long_filenames(abfd) (coff_backend_info (abfd)->_bfd_coff_long_filenames) #define bfd_coff_long_section_names(abfd) \ (coff_backend_info (abfd)->_bfd_coff_long_section_names) #define bfd_coff_default_section_alignment_power(abfd) \ (coff_backend_info (abfd)->_bfd_coff_default_section_alignment_power) #define bfd_coff_swap_filehdr_in(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_filehdr_in) (abfd, i, o)) #define bfd_coff_swap_aouthdr_in(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_aouthdr_in) (abfd, i, o)) #define bfd_coff_swap_scnhdr_in(abfd, i,o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_scnhdr_in) (abfd, i, o)) #define bfd_coff_swap_reloc_in(abfd, i, o) \ ((coff_backend_info (abfd)->_bfd_coff_swap_reloc_in) (abfd, i, o)) #define bfd_coff_bad_format_hook(abfd, filehdr) \ ((coff_backend_info (abfd)->_bfd_coff_bad_format_hook) (abfd, filehdr)) #define bfd_coff_set_arch_mach_hook(abfd, filehdr)\ ((coff_backend_info (abfd)->_bfd_coff_set_arch_mach_hook) (abfd, filehdr)) #define bfd_coff_mkobject_hook(abfd, filehdr, aouthdr)\ ((coff_backend_info (abfd)->_bfd_coff_mkobject_hook) (abfd, filehdr, aouthdr)) #define bfd_coff_styp_to_sec_flags_hook(abfd, scnhdr, name, section)\ ((coff_backend_info (abfd)->_bfd_styp_to_sec_flags_hook)\ (abfd, scnhdr, name, section)) #define bfd_coff_set_alignment_hook(abfd, sec, scnhdr)\ ((coff_backend_info (abfd)->_bfd_set_alignment_hook) (abfd, sec, scnhdr)) #define bfd_coff_slurp_symbol_table(abfd)\ ((coff_backend_info (abfd)->_bfd_coff_slurp_symbol_table) (abfd)) #define bfd_coff_symname_in_debug(abfd, sym)\ ((coff_backend_info (abfd)->_bfd_coff_symname_in_debug) (abfd, sym)) #define bfd_coff_force_symnames_in_strings(abfd)\ (coff_backend_info (abfd)->_bfd_coff_force_symnames_in_strings) #define bfd_coff_debug_string_prefix_length(abfd)\ (coff_backend_info (abfd)->_bfd_coff_debug_string_prefix_length) #define bfd_coff_print_aux(abfd, file, base, symbol, aux, indaux)\ ((coff_backend_info (abfd)->_bfd_coff_print_aux)\ (abfd, file, base, symbol, aux, indaux)) #define bfd_coff_reloc16_extra_cases(abfd, link_info, link_order, reloc, data, src_ptr, dst_ptr)\ ((coff_backend_info (abfd)->_bfd_coff_reloc16_extra_cases)\ (abfd, link_info, link_order, reloc, data, src_ptr, dst_ptr)) #define bfd_coff_reloc16_estimate(abfd, section, reloc, shrink, link_info)\ ((coff_backend_info (abfd)->_bfd_coff_reloc16_estimate)\ (abfd, section, reloc, shrink, link_info)) #define bfd_coff_classify_symbol(abfd, sym)\ ((coff_backend_info (abfd)->_bfd_coff_classify_symbol)\ (abfd, sym)) #define bfd_coff_compute_section_file_positions(abfd)\ ((coff_backend_info (abfd)->_bfd_coff_compute_section_file_positions)\ (abfd)) #define bfd_coff_start_final_link(obfd, info)\ ((coff_backend_info (obfd)->_bfd_coff_start_final_link)\ (obfd, info)) #define bfd_coff_relocate_section(obfd,info,ibfd,o,con,rel,isyms,secs)\ ((coff_backend_info (ibfd)->_bfd_coff_relocate_section)\ (obfd, info, ibfd, o, con, rel, isyms, secs)) #define bfd_coff_rtype_to_howto(abfd, sec, rel, h, sym, addendp)\ ((coff_backend_info (abfd)->_bfd_coff_rtype_to_howto)\ (abfd, sec, rel, h, sym, addendp)) #define bfd_coff_adjust_symndx(obfd, info, ibfd, sec, rel, adjustedp)\ ((coff_backend_info (abfd)->_bfd_coff_adjust_symndx)\ (obfd, info, ibfd, sec, rel, adjustedp)) #define bfd_coff_link_add_one_symbol(info,abfd,name,flags,section,value,string,cp,coll,hashp)\ ((coff_backend_info (abfd)->_bfd_coff_link_add_one_symbol)\ (info, abfd, name, flags, section, value, string, cp, coll, hashp)) #define bfd_coff_link_output_has_begun(a,p) \ ((coff_backend_info (a)->_bfd_coff_link_output_has_begun) (a,p)) #define bfd_coff_final_link_postscript(a,p) \ ((coff_backend_info (a)->_bfd_coff_final_link_postscript) (a,p)) Writing relocations ................... To write relocations, the back end steps though the canonical relocation table and create an `internal_reloc'. The symbol index to use is removed from the `offset' field in the symbol table supplied. The address comes directly from the sum of the section base address and the relocation offset; the type is dug directly from the howto field. Then the `internal_reloc' is swapped into the shape of an `external_reloc' and written out to disk. Reading linenumbers ................... Creating the linenumber table is done by reading in the entire coff linenumber table, and creating another table for internal use. A coff linenumber table is structured so that each function is marked as having a line number of 0. Each line within the function is an offset from the first line in the function. The base of the line number information for the table is stored in the symbol associated with the function. Note: The PE format uses line number 0 for a flag indicating a new source file. The information is copied from the external to the internal table, and each symbol which marks a function is marked by pointing its... How does this work ? Reading relocations ................... Coff relocations are easily transformed into the internal BFD form (`arelent'). Reading a coff relocation table is done in the following stages: * Read the entire coff relocation table into memory. * Process each relocation in turn; first swap it from the external to the internal form. * Turn the symbol referenced in the relocation's symbol index into a pointer into the canonical symbol table. This table is the same as the one returned by a call to `bfd_canonicalize_symtab'. The back end will call that routine and save the result if a canonicalization hasn't been done. * The reloc index is turned into a pointer to a howto structure, in a back end specific way. For instance, the 386 and 960 use the `r_type' to directly produce an index into a howto table vector; the 88k subtracts a number from the `r_type' field and creates an addend field.  File: bfd.info, Node: elf, Prev: coff, Up: BFD back ends ELF backends ============ BFD support for ELF formats is being worked on. Currently, the best supported back ends are for sparc and i386 (running svr4 or Solaris 2). Documentation of the internals of the support code still needs to be written. The code is changing quickly enough that we haven't bothered yet. `bfd_elf_find_section' ...................... *Synopsis* struct elf_internal_shdr *bfd_elf_find_section (bfd *abfd, char *name); *Description* Helper functions for GDB to locate the string tables. Since BFD hides string tables from callers, GDB needs to use an internal hook to find them. Sun's .stabstr, in particular, isn't even pointed to by the .stab section, so ordinary mechanisms wouldn't work to find it, even if we had some.  File: bfd.info, Node: GNU Free Documentation License, Next: Index, Prev: BFD back ends, Up: Top GNU Free Documentation License ****************************** GNU Free Documentation License Version 1.1, March 2000 Copyright (C) 2000 Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other written document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software. We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference. 1. APPLICABILITY AND DEFINITIONS This License applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language. A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (For example, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them. The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, whose contents can be viewed and edited directly and straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent. A copy that is not "Transparent" is called "Opaque". Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML designed for human modification. Opaque formats include PostScript, PDF, proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML produced by some word processors for output purposes only. The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text. 2. VERBATIM COPYING You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3. You may also lend copies, under the same conditions stated above, and you may publicly display copies. 3. COPYING IN QUANTITY If you publish printed copies of the Document numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects. If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages. If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a publicly-accessible computer-network location containing a complete Transparent copy of the Document, free of added material, which the general network-using public has access to download anonymously at no charge using public-standard network protocols. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public. It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document. 4. MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission. B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has less than five). C. State on the Title page the name of the publisher of the Modified Version, as the publisher. D. Preserve all the copyright notices of the Document. E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices. F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below. G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice. H. Include an unaltered copy of this License. I. Preserve the section entitled "History", and its title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence. J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission. K. In any section entitled "Acknowledgements" or "Dedications", preserve the section's title, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein. L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles. M. Delete any section entitled "Endorsements". Such a section may not be included in the Modified Version. N. Do not retitle any existing section as "Endorsements" or to conflict in title with any Invariant Section. If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles. You may add a section entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties-for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard. You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one. The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version. 5. COMBINING DOCUMENTS You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice. The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work. In the combination, you must combine any sections entitled "History" in the various original documents, forming one section entitled "History"; likewise combine any sections entitled "Acknowledgements", and any sections entitled "Dedications". You must delete all sections entitled "Endorsements." 6. COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects. You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document. 7. AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, does not as a whole count as a Modified Version of the Document, provided no compilation copyright is claimed for the compilation. Such a compilation is called an "aggregate", and this License does not apply to the other self-contained works thus compiled with the Document, on account of their being thus compiled, if they are not themselves derivative works of the Document. If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one quarter of the entire aggregate, the Document's Cover Texts may be placed on covers that surround only the Document within the aggregate. Otherwise they must appear on covers around the whole aggregate. 8. TRANSLATION Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License provided that you also include the original English version of this License. In case of a disagreement between the translation and the original English version of this License, the original English version will prevail. 9. TERMINATION You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. 10. FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/. Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. ADDENDUM: How to use this License for your documents To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (c) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. A copy of the license is included in the section entitled "GNU Free Documentation License". If you have no Invariant Sections, write "with no Invariant Sections" instead of saying which ones are invariant. If you have no Front-Cover Texts, write "no Front-Cover Texts" instead of "Front-Cover Texts being LIST"; likewise for Back-Cover Texts. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.