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diff --git a/gnu/usr.bin/binutils/bfd/doc/bfd.info-6 b/gnu/usr.bin/binutils/bfd/doc/bfd.info-6 deleted file mode 100644 index 0c59a3dc63d..00000000000 --- a/gnu/usr.bin/binutils/bfd/doc/bfd.info-6 +++ /dev/null @@ -1,683 +0,0 @@ -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 Free Software Foundation, Inc. - - Permission is granted to make and distribute verbatim copies of this -manual provided the copyright notice and this permission notice are -preserved on all copies. - - Permission is granted to copy and distribute modified versions of -this manual under the conditions for verbatim copying, subject to the -terms of the GNU General Public License, which includes the provision -that the entire resulting derived work is distributed under the terms -of a permission notice identical to this one. - - Permission is granted to copy and distribute translations of this -manual into another language, under the above conditions for modified -versions. - - -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; - 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_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. - |