diff options
Diffstat (limited to 'bfd/syms.c')
| -rw-r--r-- | bfd/syms.c | 288 |
1 files changed, 192 insertions, 96 deletions
@@ -1,5 +1,5 @@ /* Generic symbol-table support for the BFD library. - Copyright (C) 1990-1991 Free Software Foundation, Inc. + Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc. Written by Cygnus Support. This file is part of BFD, the Binary File Descriptor library. @@ -22,20 +22,20 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ SECTION Symbols - BFD trys to maintain as much symbol information as it can when + 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 <<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 infomation passed to - applications some targets keep some information 'behind the - sceans', in a structure only the particular back end knows + 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 was read, but was written + 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 @@ -43,8 +43,8 @@ SECTION application with pointers to the canonical information. To output symbols, the application provides BFD with a table of pointers to pointers to <<asymbol>>s. This allows applications - like the linker to output a symbol as read, since the 'behind - the sceens' information will be still available. + 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:: @@ -52,13 +52,14 @@ SECTION @* symbol handling functions:: @end menu -@node Reading Symbols, Writing Symbols, Symbols, Symbols +INODE +Reading Symbols, Writing Symbols, Symbols, Symbols SUBSECTION Reading Symbols - There are two stages to reading a symbol table from a BFD; + 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 appliction which reads the symbol table: + excerpt from an application which reads the symbol table: | unsigned int storage_needed; | asymbol **symbol_table; @@ -80,10 +81,11 @@ SUBSECTION | } All storage for the symbols themselves is in an obstack - connected to the BFD, and is freed when the BFD is closed. + connected to the BFD; it is freed when the BFD is closed. -@node Writing Symbols, typedef asymbol, Reading Symbols, Symbols +INODE +Writing Symbols, typedef asymbol, Reading Symbols, Symbols SUBSECTION Writing Symbols @@ -92,9 +94,9 @@ SUBSECTION 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 outputing code must always be provided with an - 'owned' symbol; one which has come from another BFD, or one - which has been created using <<bfd_make_empty_symbol>>. An + 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 <<bfd_make_empty_symbol>>. Here is an example showing the creation of a symbol table with only one element: | #include "bfd.h" @@ -124,7 +126,7 @@ SUBSECTION | 00012345 A dummy_symbol Many formats cannot represent arbitary symbol information; for - instance the <<a.out>> object format does not allow an + instance, the <<a.out>> object format does not allow an arbitary number of sections. A symbol pointing to a section which is not one of <<.text>>, <<.data>> or <<.bss>> cannot be described. @@ -132,8 +134,11 @@ SUBSECTION */ + /* -@node typedef asymbol, symbol handling functions, Writing Symbols, Symbols +DOCDD +INODE +typedef asymbol, symbol handling functions, Writing Symbols, Symbols */ /* @@ -147,20 +152,28 @@ SUBSECTION /* CODE_FRAGMENT +. .typedef struct symbol_cache_entry .{ . {* A pointer to the BFD which owns the symbol. This information . is necessary so that a back end can work out what additional -. (invisible to the application writer) information is carried -. with the symbol. *} +. 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; +. 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 +. {* 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.*} +. {* 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: *} @@ -175,43 +188,37 @@ CODE_FRAGMENT . value is the offset into the section of the data. *} .#define BSF_GLOBAL 0x02 . -. {* Obsolete *} -.#define BSF_IMPORT 0x04 -. -. {* The symbol has global scope, and is exported. The value is +. {* The symbol has global scope and is exported. The value is . the offset into the section of the data. *} -.#define BSF_EXPORT 0x08 -. -. {* The symbol is undefined. <<extern>> in <<C>>. The value has -. no meaning. *} -.#define BSF_UNDEFINED_OBS 0x10 -. -. {* The symbol is common, initialized to zero; default in -. <<C>>. The value is the size of the object in bytes. *} -.#define BSF_FORT_COMM_OBS 0x20 +.#define BSF_EXPORT BSF_GLOBAL {* no real difference *} . . {* A normal C symbol would be one of: . <<BSF_LOCAL>>, <<BSF_FORT_COMM>>, <<BSF_UNDEFINED>> or -. <<BSF_EXPORT|BSD_GLOBAL>> *} +. <<BSF_GLOBAL>> *} . . {* The symbol is a debugging record. The value has an arbitary . meaning. *} -.#define BSF_DEBUGGING 0x40 +.#define BSF_DEBUGGING 0x08 . -. {* Used by the linker *} -.#define BSF_KEEP 0x10000 -.#define BSF_KEEP_G 0x80000 +. {* The symbol denotes a function entry point. Used in ELF, +. perhaps others someday. *} +.#define BSF_FUNCTION 0x10 . -. {* Unused *} -.#define BSF_WEAK 0x100000 -.#define BSF_CTOR 0x200000 +. {* Used by the linker. *} +.#define BSF_KEEP 0x20 +.#define BSF_KEEP_G 0x40 . -. {* This symbol was created to point to a section *} -.#define BSF_SECTION_SYM 0x400000 +. {* 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 0x800000 +.#define BSF_OLD_COMMON 0x200 . . {* The default value for common data. *} .#define BFD_FORT_COMM_DEFAULT_VALUE 0 @@ -222,21 +229,25 @@ CODE_FRAGMENT . 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 0x40000 +.#define BSF_NOT_AT_END 0x400 . . {* Signal that the symbol is the label of constructor section. *} -.#define BSF_CONSTRUCTOR 0x1000000 +.#define BSF_CONSTRUCTOR 0x800 . . {* Signal that the symbol is a warning symbol. If the symbol . is a warning symbol, then the value field (I know this is . tacky) will point to the asymbol which when referenced will . cause the warning. *} -.#define BSF_WARNING 0x2000000 +.#define BSF_WARNING 0x1000 . . {* Signal that the symbol is indirect. The value of the symbol . is a pointer to an undefined asymbol which contains the . name to use instead. *} -.#define BSF_INDIRECT 0x4000000 +.#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 . . flagword flags; . @@ -247,18 +258,21 @@ CODE_FRAGMENT . . {* Back end special data. This is being phased out in favour . of making this a union. *} -. PTR udata; +. PTR udata; . .} asymbol; */ #include "bfd.h" #include "sysdep.h" + #include "libbfd.h" #include "aout/stab_gnu.h" /* -@node symbol handling functions, , typedef asymbol, Symbols +DOCDD +INODE +symbol handling functions, , typedef asymbol, Symbols SUBSECTION Symbol Handling Functions */ @@ -268,10 +282,10 @@ FUNCTION get_symtab_upper_bound DESCRIPTION - Returns the number of bytes required in a vector of pointers - to <<asymbols>> for all the symbols in the supplied BFD, + Return the number of bytes required to store a vector of pointers + to <<asymbols>> for all the symbols in the BFD @var{abfd}, including a terminal NULL pointer. If there are no symbols in - the BFD, then 0 is returned. + the BFD, then return 0. .#define get_symtab_upper_bound(abfd) \ . BFD_SEND (abfd, _get_symtab_upper_bound, (abfd)) @@ -283,10 +297,10 @@ FUNCTION bfd_canonicalize_symtab DESCRIPTION - Supplied a BFD and a pointer to an uninitialized vector of - pointers. This reads in the symbols from the BFD, and fills in - the table with pointers to the symbols, and a trailing NULL. - The routine returns the actual number of symbol pointers not + 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. @@ -301,12 +315,13 @@ DESCRIPTION FUNCTION bfd_set_symtab -DESCRIPTION - Provided a table of pointers to symbols and a count, writes to - the output BFD the symbols when closed. - SYNOPSIS - boolean bfd_set_symtab (bfd *, asymbol **, unsigned int ); + boolean bfd_set_symtab (bfd *abfd, asymbol **location, unsigned int count); + +DESCRIPTION + Arrange that when the output BFD @var{abfd} is closed, + the table @var{location} of @var{count} pointers to symbols + will be written. */ boolean @@ -329,11 +344,12 @@ bfd_set_symtab (abfd, location, symcount) FUNCTION bfd_print_symbol_vandf -DESCRIPTION - Prints the value and flags of the symbol supplied to the stream file. - SYNOPSIS void bfd_print_symbol_vandf(PTR file, asymbol *symbol); + +DESCRIPTION + Print the value and flags of the @var{symbol} supplied to the + stream @var{file}. */ void DEFUN(bfd_print_symbol_vandf,(file, symbol), @@ -349,11 +365,10 @@ asymbol *symbol) { fprintf_vma(file, symbol->value); } - fprintf(file," %c%c%c%c%c%c%c%c", + fprintf(file," %c%c%c%c%c%c%c", (type & BSF_LOCAL) ? 'l':' ', (type & BSF_GLOBAL) ? 'g' : ' ', - (type & BSF_IMPORT) ? 'i' : ' ', - (type & BSF_EXPORT) ? 'e' : ' ', + (type & BSF_WEAK) ? 'w' : ' ', (type & BSF_CONSTRUCTOR) ? 'C' : ' ', (type & BSF_WARNING) ? 'W' : ' ', (type & BSF_INDIRECT) ? 'I' : ' ', @@ -367,10 +382,10 @@ FUNCTION bfd_make_empty_symbol DESCRIPTION - This function creates a new <<asymbol>> structure for the BFD, - and returns a pointer to it. + Create a new <<asymbol>> structure for the BFD @var{abfd} + and return a pointer to it. - This routine is necessary, since each back end has private + This routine is necessary because each back end has private information surrounding the <<asymbol>>. Building your own <<asymbol>> and pointing to it will not create the private information, and will cause problems later on. @@ -381,11 +396,66 @@ DESCRIPTION /* FUNCTION + bfd_make_debug_symbol + +DESCRIPTION + Create a new <<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. + +.#define bfd_make_debug_symbol(abfd,ptr,size) \ +. BFD_SEND (abfd, _bfd_make_debug_symbol, (abfd, ptr, size)) +*/ + +struct section_to_type +{ + CONST char *section; + char type; +}; + +/* Map section names to POSIX/BSD single-character symbol types. + This table is probably incomplete. It is sorted for convenience of + adding entries. Since it is so short, a linear search is used. */ +static CONST struct section_to_type stt[] = { + {"*DEBUG*", 'N'}, + {".bss", 'b'}, + {".data", 'd'}, + {".sbss", 's'}, /* Small BSS (uninitialized data) */ + {".scommon", 'c'}, /* Small common */ + {".sdata", 'g'}, /* Small initialized data */ + {".text", 't'}, + {0, 0} +}; + +/* Return the single-character symbol type corresponding to + section S, or '?' for an unknown COFF section. */ + +static char +coff_section_type (s) + char *s; +{ + CONST struct section_to_type *t; + + for (t = &stt[0]; t->section; t++) + if (!strcmp (s, t->section)) + return t->type; + return '?'; +} + +#ifndef islower +#define islower(c) ((c) >= 'a' && (c) <= 'z') +#endif +#ifndef toupper +#define toupper(c) (islower(c) ? ((c) & ~0x20) : (c)) +#endif + +/* +FUNCTION bfd_decode_symclass DESCRIPTION - Return a lower-case character corresponding to the symbol - class of symbol. + Return a character corresponding to the symbol + class of @var{symbol}, or '?' for an unknown class. SYNOPSIS int bfd_decode_symclass(asymbol *symbol); @@ -394,23 +464,26 @@ int DEFUN(bfd_decode_symclass,(symbol), asymbol *symbol) { - flagword flags = symbol->flags; - - if (symbol->section == &bfd_com_section) return 'C'; - if (symbol->section == &bfd_und_section) return 'U'; - - if ( flags & (BSF_GLOBAL|BSF_LOCAL) ) { - if ( symbol->section == &bfd_abs_section) - return (flags & BSF_GLOBAL) ? 'A' : 'a'; - else if ( !strcmp(symbol->section->name, ".text") ) - return (flags & BSF_GLOBAL) ? 'T' : 't'; - else if ( !strcmp(symbol->section->name, ".data") ) - return (flags & BSF_GLOBAL) ? 'D' : 'd'; - else if ( !strcmp(symbol->section->name, ".bss") ) - return (flags & BSF_GLOBAL) ? 'B' : 'b'; - else - return (flags & BSF_GLOBAL) ? 'O' : 'o'; - } + char c; + + if (bfd_is_com_section (symbol->section)) + return 'C'; + if (symbol->section == &bfd_und_section) + return 'U'; + if (symbol->section == &bfd_ind_section) + return 'I'; + if (!(symbol->flags & (BSF_GLOBAL|BSF_LOCAL))) + return '?'; + + if (symbol->section == &bfd_abs_section) + c = 'a'; + else if (symbol->section) + c = coff_section_type (symbol->section->name); + else + return '?'; + if (symbol->flags & BSF_GLOBAL) + c = toupper (c); + return c; /* We don't have to handle these cases just yet, but we will soon: N_SETV: 'v'; @@ -420,14 +493,37 @@ asymbol *symbol) N_SETB: 's'; N_INDR: 'i'; */ - - return '?'; } +/* +FUNCTION + bfd_symbol_info + +DESCRIPTION + Fill in the basic info about symbol that nm needs. + Additional info may be added by the back-ends after + calling this function. + +SYNOPSIS + void bfd_symbol_info(asymbol *symbol, symbol_info *ret); +*/ +void +DEFUN(bfd_symbol_info,(symbol, ret), + asymbol *symbol AND + symbol_info *ret) +{ + ret->type = bfd_decode_symclass (symbol); + if (ret->type != 'U') + ret->value = symbol->value+symbol->section->vma; + else + ret->value = 0; + ret->name = symbol->name; +} + +void bfd_symbol_is_absolute() { - abort(); } |