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author | dim <dim@FreeBSD.org> | 2010-11-01 19:35:33 +0000 |
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committer | dim <dim@FreeBSD.org> | 2010-11-01 19:35:33 +0000 |
commit | 3f5c947f4453c6016a2a6a9636367ee3f48fc6fc (patch) | |
tree | 461aafc934d462eb9b9221308f8e25238c0ada62 /contrib/binutils/bfd/doc/syms.texi | |
parent | e6be3e7867eb43d220575baee2ce5662fb03e46c (diff) | |
parent | d0f678fa0ff3f08a4eca29daf4d1ac39797b6326 (diff) | |
download | FreeBSD-src-3f5c947f4453c6016a2a6a9636367ee3f48fc6fc.zip FreeBSD-src-3f5c947f4453c6016a2a6a9636367ee3f48fc6fc.tar.gz |
Merge ^/vendor/binutils/dist@214571 into contrib/binutils, which brings
us up to version 2.17.50.20070703, at the last GPLv2 commit.
Amongst others, this added upstream support for some FreeBSD-specific
things that we previously had to manually hack in, such as the OSABI
label support, and so on.
There are also quite a number of new files, some for cpu's (e.g. SPU)
that we may or may not be interested in, but those can be cleaned up
later on, if needed.
Diffstat (limited to 'contrib/binutils/bfd/doc/syms.texi')
-rw-r--r-- | contrib/binutils/bfd/doc/syms.texi | 461 |
1 files changed, 0 insertions, 461 deletions
diff --git a/contrib/binutils/bfd/doc/syms.texi b/contrib/binutils/bfd/doc/syms.texi deleted file mode 100644 index dc56bbc..0000000 --- a/contrib/binutils/bfd/doc/syms.texi +++ /dev/null @@ -1,461 +0,0 @@ -@section Symbols -BFD tries to maintain as much symbol information as it can when -it moves information from file to file. BFD passes information -to applications though the @code{asymbol} structure. When the -application requests the symbol table, BFD reads the table in -the native form and translates parts of it into the internal -format. To maintain more than the information passed to -applications, some targets keep some information ``behind the -scenes'' in a structure only the particular back end knows -about. For example, the coff back end keeps the original -symbol table structure as well as the canonical structure when -a BFD is read in. On output, the coff back end can reconstruct -the output symbol table so that no information is lost, even -information unique to coff which BFD doesn't know or -understand. If a coff symbol table were read, but were written -through an a.out back end, all the coff specific information -would be lost. The symbol table of a BFD -is not necessarily read in until a canonicalize request is -made. Then the BFD back end fills in a table provided by the -application with pointers to the canonical information. To -output symbols, the application provides BFD with a table of -pointers to pointers to @code{asymbol}s. This allows applications -like the linker to output a symbol as it was read, since the ``behind -the scenes'' information will be still available. -@menu -* Reading Symbols:: -* Writing Symbols:: -* Mini Symbols:: -* typedef asymbol:: -* symbol handling functions:: -@end menu - -@node Reading Symbols, Writing Symbols, Symbols, Symbols -@subsection Reading symbols -There are two stages to reading a symbol table from a BFD: -allocating storage, and the actual reading process. This is an -excerpt from an application which reads the symbol table: - -@example - long storage_needed; - asymbol **symbol_table; - long number_of_symbols; - long i; - - storage_needed = bfd_get_symtab_upper_bound (abfd); - - if (storage_needed < 0) - FAIL - - if (storage_needed == 0) - return; - - symbol_table = xmalloc (storage_needed); - ... - number_of_symbols = - bfd_canonicalize_symtab (abfd, symbol_table); - - if (number_of_symbols < 0) - FAIL - - for (i = 0; i < number_of_symbols; i++) - process_symbol (symbol_table[i]); -@end example - -All storage for the symbols themselves is in an objalloc -connected to the BFD; it is freed when the BFD is closed. - -@node Writing Symbols, Mini Symbols, Reading Symbols, Symbols -@subsection Writing symbols -Writing of a symbol table is automatic when a BFD open for -writing is closed. The application attaches a vector of -pointers to pointers to symbols to the BFD being written, and -fills in the symbol count. The close and cleanup code reads -through the table provided and performs all the necessary -operations. The BFD output code must always be provided with an -``owned'' symbol: one which has come from another BFD, or one -which has been created using @code{bfd_make_empty_symbol}. Here is an -example showing the creation of a symbol table with only one element: - -@example - #include "bfd.h" - int main (void) - @{ - bfd *abfd; - asymbol *ptrs[2]; - asymbol *new; - - abfd = bfd_openw ("foo","a.out-sunos-big"); - bfd_set_format (abfd, bfd_object); - new = bfd_make_empty_symbol (abfd); - new->name = "dummy_symbol"; - new->section = bfd_make_section_old_way (abfd, ".text"); - new->flags = BSF_GLOBAL; - new->value = 0x12345; - - ptrs[0] = new; - ptrs[1] = 0; - - bfd_set_symtab (abfd, ptrs, 1); - bfd_close (abfd); - return 0; - @} - - ./makesym - nm foo - 00012345 A dummy_symbol -@end example - -Many formats cannot represent arbitrary symbol information; for -instance, the @code{a.out} object format does not allow an -arbitrary number of sections. A symbol pointing to a section -which is not one of @code{.text}, @code{.data} or @code{.bss} cannot -be described. - -@node Mini Symbols, typedef asymbol, Writing Symbols, Symbols -@subsection Mini Symbols -Mini symbols provide read-only access to the symbol table. -They use less memory space, but require more time to access. -They can be useful for tools like nm or objdump, which may -have to handle symbol tables of extremely large executables. - -The @code{bfd_read_minisymbols} function will read the symbols -into memory in an internal form. It will return a @code{void *} -pointer to a block of memory, a symbol count, and the size of -each symbol. The pointer is allocated using @code{malloc}, and -should be freed by the caller when it is no longer needed. - -The function @code{bfd_minisymbol_to_symbol} will take a pointer -to a minisymbol, and a pointer to a structure returned by -@code{bfd_make_empty_symbol}, and return a @code{asymbol} structure. -The return value may or may not be the same as the value from -@code{bfd_make_empty_symbol} which was passed in. - - -@node typedef asymbol, symbol handling functions, Mini Symbols, Symbols -@subsection typedef asymbol -An @code{asymbol} has the form: - - -@example - -typedef struct bfd_symbol -@{ - /* A pointer to the BFD which owns the symbol. This information - is necessary so that a back end can work out what additional - information (invisible to the application writer) is carried - with the symbol. - - This field is *almost* redundant, since you can use section->owner - instead, except that some symbols point to the global sections - bfd_@{abs,com,und@}_section. This could be fixed by making - these globals be per-bfd (or per-target-flavor). FIXME. */ - struct bfd *the_bfd; /* Use bfd_asymbol_bfd(sym) to access this field. */ - - /* The text of the symbol. The name is left alone, and not copied; the - application may not alter it. */ - const char *name; - - /* The value of the symbol. This really should be a union of a - numeric value with a pointer, since some flags indicate that - a pointer to another symbol is stored here. */ - symvalue value; - - /* Attributes of a symbol. */ -#define BSF_NO_FLAGS 0x00 - - /* The symbol has local scope; @code{static} in @code{C}. The value - is the offset into the section of the data. */ -#define BSF_LOCAL 0x01 - - /* The symbol has global scope; initialized data in @code{C}. The - value is the offset into the section of the data. */ -#define BSF_GLOBAL 0x02 - - /* The symbol has global scope and is exported. The value is - the offset into the section of the data. */ -#define BSF_EXPORT BSF_GLOBAL /* No real difference. */ - - /* A normal C symbol would be one of: - @code{BSF_LOCAL}, @code{BSF_FORT_COMM}, @code{BSF_UNDEFINED} or - @code{BSF_GLOBAL}. */ - - /* The symbol is a debugging record. The value has an arbitrary - meaning, unless BSF_DEBUGGING_RELOC is also set. */ -#define BSF_DEBUGGING 0x08 - - /* The symbol denotes a function entry point. Used in ELF, - perhaps others someday. */ -#define BSF_FUNCTION 0x10 - - /* Used by the linker. */ -#define BSF_KEEP 0x20 -#define BSF_KEEP_G 0x40 - - /* A weak global symbol, overridable without warnings by - a regular global symbol of the same name. */ -#define BSF_WEAK 0x80 - - /* This symbol was created to point to a section, e.g. ELF's - STT_SECTION symbols. */ -#define BSF_SECTION_SYM 0x100 - - /* The symbol used to be a common symbol, but now it is - allocated. */ -#define BSF_OLD_COMMON 0x200 - - /* The default value for common data. */ -#define BFD_FORT_COMM_DEFAULT_VALUE 0 - - /* In some files the type of a symbol sometimes alters its - location in an output file - ie in coff a @code{ISFCN} symbol - which is also @code{C_EXT} symbol appears where it was - declared and not at the end of a section. This bit is set - by the target BFD part to convey this information. */ -#define BSF_NOT_AT_END 0x400 - - /* Signal that the symbol is the label of constructor section. */ -#define BSF_CONSTRUCTOR 0x800 - - /* Signal that the symbol is a warning symbol. The name is a - warning. The name of the next symbol is the one to warn about; - if a reference is made to a symbol with the same name as the next - symbol, a warning is issued by the linker. */ -#define BSF_WARNING 0x1000 - - /* Signal that the symbol is indirect. This symbol is an indirect - pointer to the symbol with the same name as the next symbol. */ -#define BSF_INDIRECT 0x2000 - - /* BSF_FILE marks symbols that contain a file name. This is used - for ELF STT_FILE symbols. */ -#define BSF_FILE 0x4000 - - /* Symbol is from dynamic linking information. */ -#define BSF_DYNAMIC 0x8000 - - /* The symbol denotes a data object. Used in ELF, and perhaps - others someday. */ -#define BSF_OBJECT 0x10000 - - /* This symbol is a debugging symbol. The value is the offset - into the section of the data. BSF_DEBUGGING should be set - as well. */ -#define BSF_DEBUGGING_RELOC 0x20000 - - /* This symbol is thread local. Used in ELF. */ -#define BSF_THREAD_LOCAL 0x40000 - - flagword flags; - - /* A pointer to the section to which this symbol is - relative. This will always be non NULL, there are special - sections for undefined and absolute symbols. */ - struct bfd_section *section; - - /* Back end special data. */ - union - @{ - void *p; - bfd_vma i; - @} - udata; -@} -asymbol; - -@end example - -@node symbol handling functions, , typedef asymbol, Symbols -@subsection Symbol handling functions - - -@findex bfd_get_symtab_upper_bound -@subsubsection @code{bfd_get_symtab_upper_bound} -@strong{Description}@* -Return the number of bytes required to store a vector of pointers -to @code{asymbols} for all the symbols in the BFD @var{abfd}, -including a terminal NULL pointer. If there are no symbols in -the BFD, then return 0. If an error occurs, return -1. -@example -#define bfd_get_symtab_upper_bound(abfd) \ - BFD_SEND (abfd, _bfd_get_symtab_upper_bound, (abfd)) - -@end example - -@findex bfd_is_local_label -@subsubsection @code{bfd_is_local_label} -@strong{Synopsis} -@example -bfd_boolean bfd_is_local_label (bfd *abfd, asymbol *sym); -@end example -@strong{Description}@* -Return TRUE if the given symbol @var{sym} in the BFD @var{abfd} is -a compiler generated local label, else return FALSE. - -@findex bfd_is_local_label_name -@subsubsection @code{bfd_is_local_label_name} -@strong{Synopsis} -@example -bfd_boolean bfd_is_local_label_name (bfd *abfd, const char *name); -@end example -@strong{Description}@* -Return TRUE if a symbol with the name @var{name} in the BFD -@var{abfd} is a compiler generated local label, else return -FALSE. This just checks whether the name has the form of a -local label. -@example -#define bfd_is_local_label_name(abfd, name) \ - BFD_SEND (abfd, _bfd_is_local_label_name, (abfd, name)) - -@end example - -@findex bfd_is_target_special_symbol -@subsubsection @code{bfd_is_target_special_symbol} -@strong{Synopsis} -@example -bfd_boolean bfd_is_target_special_symbol (bfd *abfd, asymbol *sym); -@end example -@strong{Description}@* -Return TRUE iff a symbol @var{sym} in the BFD @var{abfd} is something -special to the particular target represented by the BFD. Such symbols -should normally not be mentioned to the user. -@example -#define bfd_is_target_special_symbol(abfd, sym) \ - BFD_SEND (abfd, _bfd_is_target_special_symbol, (abfd, sym)) - -@end example - -@findex bfd_canonicalize_symtab -@subsubsection @code{bfd_canonicalize_symtab} -@strong{Description}@* -Read the symbols from the BFD @var{abfd}, and fills in -the vector @var{location} with pointers to the symbols and -a trailing NULL. -Return the actual number of symbol pointers, not -including the NULL. -@example -#define bfd_canonicalize_symtab(abfd, location) \ - BFD_SEND (abfd, _bfd_canonicalize_symtab, (abfd, location)) - -@end example - -@findex bfd_set_symtab -@subsubsection @code{bfd_set_symtab} -@strong{Synopsis} -@example -bfd_boolean bfd_set_symtab - (bfd *abfd, asymbol **location, unsigned int count); -@end example -@strong{Description}@* -Arrange that when the output BFD @var{abfd} is closed, -the table @var{location} of @var{count} pointers to symbols -will be written. - -@findex bfd_print_symbol_vandf -@subsubsection @code{bfd_print_symbol_vandf} -@strong{Synopsis} -@example -void bfd_print_symbol_vandf (bfd *abfd, void *file, asymbol *symbol); -@end example -@strong{Description}@* -Print the value and flags of the @var{symbol} supplied to the -stream @var{file}. - -@findex bfd_make_empty_symbol -@subsubsection @code{bfd_make_empty_symbol} -@strong{Description}@* -Create a new @code{asymbol} structure for the BFD @var{abfd} -and return a pointer to it. - -This routine is necessary because each back end has private -information surrounding the @code{asymbol}. Building your own -@code{asymbol} and pointing to it will not create the private -information, and will cause problems later on. -@example -#define bfd_make_empty_symbol(abfd) \ - BFD_SEND (abfd, _bfd_make_empty_symbol, (abfd)) - -@end example - -@findex _bfd_generic_make_empty_symbol -@subsubsection @code{_bfd_generic_make_empty_symbol} -@strong{Synopsis} -@example -asymbol *_bfd_generic_make_empty_symbol (bfd *); -@end example -@strong{Description}@* -Create a new @code{asymbol} structure for the BFD @var{abfd} -and return a pointer to it. Used by core file routines, -binary back-end and anywhere else where no private info -is needed. - -@findex bfd_make_debug_symbol -@subsubsection @code{bfd_make_debug_symbol} -@strong{Description}@* -Create a new @code{asymbol} structure for the BFD @var{abfd}, -to be used as a debugging symbol. Further details of its use have -yet to be worked out. -@example -#define bfd_make_debug_symbol(abfd,ptr,size) \ - BFD_SEND (abfd, _bfd_make_debug_symbol, (abfd, ptr, size)) - -@end example - -@findex bfd_decode_symclass -@subsubsection @code{bfd_decode_symclass} -@strong{Description}@* -Return a character corresponding to the symbol -class of @var{symbol}, or '?' for an unknown class. - -@strong{Synopsis} -@example -int bfd_decode_symclass (asymbol *symbol); -@end example -@findex bfd_is_undefined_symclass -@subsubsection @code{bfd_is_undefined_symclass} -@strong{Description}@* -Returns non-zero if the class symbol returned by -bfd_decode_symclass represents an undefined symbol. -Returns zero otherwise. - -@strong{Synopsis} -@example -bfd_boolean bfd_is_undefined_symclass (int symclass); -@end example -@findex bfd_symbol_info -@subsubsection @code{bfd_symbol_info} -@strong{Description}@* -Fill in the basic info about symbol that nm needs. -Additional info may be added by the back-ends after -calling this function. - -@strong{Synopsis} -@example -void bfd_symbol_info (asymbol *symbol, symbol_info *ret); -@end example -@findex bfd_copy_private_symbol_data -@subsubsection @code{bfd_copy_private_symbol_data} -@strong{Synopsis} -@example -bfd_boolean bfd_copy_private_symbol_data - (bfd *ibfd, asymbol *isym, bfd *obfd, asymbol *osym); -@end example -@strong{Description}@* -Copy private symbol information from @var{isym} in the BFD -@var{ibfd} to the symbol @var{osym} in the BFD @var{obfd}. -Return @code{TRUE} on success, @code{FALSE} on error. Possible error -returns are: - -@itemize @bullet - -@item -@code{bfd_error_no_memory} - -Not enough memory exists to create private data for @var{osec}. -@end itemize -@example -#define bfd_copy_private_symbol_data(ibfd, isymbol, obfd, osymbol) \ - BFD_SEND (obfd, _bfd_copy_private_symbol_data, \ - (ibfd, isymbol, obfd, osymbol)) - -@end example - |