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/* Generic symbol-table support for the BFD library.

   Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,

   2000, 2001, 2002

   Free Software Foundation, Inc.

   Written by Cygnus Support.

This file is part of BFD, the Binary File Descriptor library.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/*

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 <<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 <<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

INODE

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:

|         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 = (asymbol **) 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]);

|         }

        All storage for the symbols themselves is in an objalloc

        connected to the BFD; it is freed when the BFD is closed.

INODE

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 <<bfd_make_empty_symbol>>.  Here is an

        example showing the creation of a symbol table with only one element:

|       #include "bfd.h"

|       main()

|       {

|         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] = (asymbol *)0;

|

|         bfd_set_symtab(abfd, ptrs, 1);

|         bfd_close(abfd);

|       }

|

|       ./makesym

|       nm foo

|       00012345 A dummy_symbol

        Many formats cannot represent arbitary symbol information; for

        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.

INODE

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 <<bfd_read_minisymbols>> function will read the symbols

        into memory in an internal form.  It will return a <<void *>>

        pointer to a block of memory, a symbol count, and the size of

        each symbol.  The pointer is allocated using <<malloc>>, and

        should be freed by the caller when it is no longer needed.

        The function <<bfd_minisymbol_to_symbol>> will take a pointer

        to a minisymbol, and a pointer to a structure returned by

        <<bfd_make_empty_symbol>>, and return a <<asymbol>> structure.

        The return value may or may not be the same as the value from

        <<bfd_make_empty_symbol>> which was passed in.

*/

/*

DOCDD

INODE

typedef asymbol, symbol handling functions, Mini Symbols, Symbols

*/

/*

SUBSECTION

        typedef asymbol

        An <<asymbol>> has the form:

*/

/*

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

.     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; <<static>> in <<C>>. The value

.     is the offset into the section of the data.  *}

.#define BSF_LOCAL      0x01

.

.  {* The symbol has global scope; initialized data in <<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:

.     <<BSF_LOCAL>>, <<BSF_FORT_COMM>>,  <<BSF_UNDEFINED>> or

.     <<BSF_GLOBAL>>.  *}

.

.  {* The symbol is a debugging record. The value has an arbitary

.     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 <<ISFCN>> symbol

.     which is also <<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 sec *section;

.

.  {* Back end special data.  *}

.  union

.    {

.      PTR p;

.      bfd_vma i;

.    }

.  udata;

.}

.asymbol;

.

*/

#include "bfd.h"

#include "sysdep.h"

#include "libbfd.h"

#include "safe-ctype.h"

#include "bfdlink.h"

#include "aout/stab_gnu.h"

static char coff_section_type PARAMS ((const char *));

static char decode_section_type PARAMS ((const struct sec *));

static int cmpindexentry PARAMS ((const PTR, const PTR));

/*

DOCDD

INODE

symbol handling functions,  , typedef asymbol, Symbols

SUBSECTION

        Symbol handling functions

*/

/*

FUNCTION

        bfd_get_symtab_upper_bound

DESCRIPTION

        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 return 0.  If an error occurs, return -1.

.#define bfd_get_symtab_upper_bound(abfd) \

.     BFD_SEND (abfd, _bfd_get_symtab_upper_bound, (abfd))

.

*/

/*

FUNCTION

        bfd_is_local_label

SYNOPSIS

        boolean bfd_is_local_label(bfd *abfd, asymbol *sym);

DESCRIPTION

        Return true if the given symbol @var{sym} in the BFD @var{abfd} is

        a compiler generated local label, else return false.

*/

boolean

bfd_is_local_label (abfd, sym)

     bfd *abfd;

     asymbol *sym;

{

  /* The BSF_SECTION_SYM check is needed for IA-64, where every label that

     starts with '.' is local.  This would accidentally catch section names

     if we didn't reject them here.  */

  if ((sym->flags & (BSF_GLOBAL | BSF_WEAK | BSF_SECTION_SYM)) != 0)

    return false;

  if (sym->name == NULL)

    return false;

  return bfd_is_local_label_name (abfd, sym->name);

}

/*

FUNCTION

        bfd_is_local_label_name

SYNOPSIS

        boolean bfd_is_local_label_name(bfd *abfd, const char *name);

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.

.#define bfd_is_local_label_name(abfd, name) \

.     BFD_SEND (abfd, _bfd_is_local_label_name, (abfd, name))

.

*/

/*

FUNCTION

        bfd_canonicalize_symtab

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.

.#define bfd_canonicalize_symtab(abfd, location) \

.     BFD_SEND (abfd, _bfd_canonicalize_symtab,\

.                  (abfd, location))

.

*/

/*

FUNCTION

        bfd_set_symtab

SYNOPSIS

        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

bfd_set_symtab (abfd, location, symcount)

     bfd *abfd;

     asymbol **location;

     unsigned int symcount;

{

  if ((abfd->format != bfd_object) || (bfd_read_p (abfd)))

    {

      bfd_set_error (bfd_error_invalid_operation);

      return false;

    }

  bfd_get_outsymbols (abfd) = location;

  bfd_get_symcount (abfd) = symcount;

  return true;

}

/*

FUNCTION

        bfd_print_symbol_vandf

SYNOPSIS

        void bfd_print_symbol_vandf(bfd *abfd, PTR file, asymbol *symbol);

DESCRIPTION

        Print the value and flags of the @var{symbol} supplied to the

        stream @var{file}.

*/

void

bfd_print_symbol_vandf (abfd, arg, symbol)

     bfd *abfd;

     PTR arg;

     asymbol *symbol;

{

  FILE *file = (FILE *) arg;

  flagword type = symbol->flags;

  if (symbol->section != (asection *) NULL)

    {

      bfd_fprintf_vma (abfd, file,

                       symbol->value + symbol->section->vma);

    }

  else

    {

      bfd_fprintf_vma (abfd, file, symbol->value);

    }

  /* This presumes that a symbol can not be both BSF_DEBUGGING and

     BSF_DYNAMIC, nor more than one of BSF_FUNCTION, BSF_FILE, and

     BSF_OBJECT.  */

  fprintf (file, " %c%c%c%c%c%c%c",

           ((type & BSF_LOCAL)

            ? (type & BSF_GLOBAL) ? '!' : 'l'

            : (type & BSF_GLOBAL) ? 'g' : ' '),

           (type & BSF_WEAK) ? 'w' : ' ',

           (type & BSF_CONSTRUCTOR) ? 'C' : ' ',

           (type & BSF_WARNING) ? 'W' : ' ',

           (type & BSF_INDIRECT) ? 'I' : ' ',

           (type & BSF_DEBUGGING) ? 'd' : (type & BSF_DYNAMIC) ? 'D' : ' ',

           ((type & BSF_FUNCTION)

            ? 'F'

            : ((type & BSF_FILE)

               ? 'f'

               : ((type & BSF_OBJECT) ? 'O' : ' '))));

}

/*

FUNCTION

        bfd_make_empty_symbol

DESCRIPTION

        Create a new <<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 <<asymbol>>. Building your own

        <<asymbol>> and pointing to it will not create the private

        information, and will cause problems later on.

.#define bfd_make_empty_symbol(abfd) \

.     BFD_SEND (abfd, _bfd_make_empty_symbol, (abfd))

.

*/

/*

FUNCTION

        _bfd_generic_make_empty_symbol

SYNOPSIS

        asymbol *_bfd_generic_make_empty_symbol (bfd *);

DESCRIPTION

        Create a new <<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.

*/

asymbol *

_bfd_generic_make_empty_symbol (abfd)

     bfd *abfd;

{

  bfd_size_type amt = sizeof (asymbol);

  asymbol *new = (asymbol *) bfd_zalloc (abfd, amt);

  if (new)

    new->the_bfd = abfd;

  return new;

}

/*

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[] =

{

  {".bss", 'b'},

  {"code", 't'},                /* MRI .text */

  {".data", 'd'},

  {"*DEBUG*", 'N'},

  {".debug", 'N'},              /* MSVC's .debug (non-standard debug syms) */

  {".drectve", 'i'},            /* MSVC's .drective section */

  {".edata", 'e'},              /* MSVC's .edata (export) section */

  {".fini", 't'},               /* ELF fini section */

  {".idata", 'i'},              /* MSVC's .idata (import) section */

  {".init", 't'},               /* ELF init section */

  {".pdata", 'p'},              /* MSVC's .pdata (stack unwind) section */

  {".rdata", 'r'},              /* Read only data.  */

  {".rodata", 'r'},             /* Read only data.  */

  {".sbss", 's'},               /* Small BSS (uninitialized data).  */

  {".scommon", 'c'},            /* Small common.  */

  {".sdata", 'g'},              /* Small initialized data.  */

  {".text", 't'},

  {"vars", 'd'},                /* MRI .data */

  {"zerovars", 'b'},            /* MRI .bss */

  {0, 0}

};

/* Return the single-character symbol type corresponding to

   section S, or '?' for an unknown COFF section.

   Check for any leading string which matches, so .text5 returns

   't' as well as .text */

static char

coff_section_type (s)

     const char *s;

{

  const struct section_to_type *t;

  for (t = &stt[0]; t->section; t++)

    if (!strncmp (s, t->section, strlen (t->section)))

      return t->type;

  return '?';

}

/* Return the single-character symbol type corresponding to section

   SECTION, or '?' for an unknown section.  This uses section flags to

   identify sections.

   FIXME These types are unhandled: c, i, e, p.  If we handled these also,

   we could perhaps obsolete coff_section_type.  */

static char

decode_section_type (section)

     const struct sec *section;

{

  if (section->flags & SEC_CODE)

    return 't';

  if (section->flags & SEC_DATA)

    {

      if (section->flags & SEC_READONLY)

        return 'r';

      else if (section->flags & SEC_SMALL_DATA)

        return 'g';

      else

        return 'd';

    }

  if ((section->flags & SEC_HAS_CONTENTS) == 0)

    {

      if (section->flags & SEC_SMALL_DATA)

        return 's';

      else

        return 'b';

    }

  if (section->flags & SEC_DEBUGGING)

    return 'N';

  return '?';

}

/*

FUNCTION

        bfd_decode_symclass

DESCRIPTION

        Return a character corresponding to the symbol

        class of @var{symbol}, or '?' for an unknown class.

SYNOPSIS

        int bfd_decode_symclass(asymbol *symbol);

*/

int

bfd_decode_symclass (symbol)

     asymbol *symbol;

{

  char c;

  if (bfd_is_com_section (symbol->section))

    return 'C';

  if (bfd_is_und_section (symbol->section))

    {

      if (symbol->flags & BSF_WEAK)

        {

          /* If weak, determine if it's specifically an object

             or non-object weak.  */

          if (symbol->flags & BSF_OBJECT)

            return 'v';

          else

            return 'w';

        }

      else

        return 'U';

    }

  if (bfd_is_ind_section (symbol->section))

    return 'I';

  if (symbol->flags & BSF_WEAK)

    {

      /* If weak, determine if it's specifically an object

         or non-object weak.  */

      if (symbol->flags & BSF_OBJECT)

        return 'V';

      else

        return 'W';

    }

  if (!(symbol->flags & (BSF_GLOBAL | BSF_LOCAL)))

    return '?';

  if (bfd_is_abs_section (symbol->section))

    c = 'a';

  else if (symbol->section)

    {

      c = coff_section_type (symbol->section->name);

      if (c == '?')

        c = decode_section_type (symbol->section);

    }

  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';

     N_SETA: 'l';

     N_SETT: 'x';

     N_SETD: 'z';

     N_SETB: 's';

     N_INDR: 'i';

     */

}

/*

FUNCTION

        bfd_is_undefined_symclass

DESCRIPTION

        Returns non-zero if the class symbol returned by

        bfd_decode_symclass represents an undefined symbol.

        Returns zero otherwise.

SYNOPSIS

        boolean bfd_is_undefined_symclass (int symclass);

*/

boolean

bfd_is_undefined_symclass (symclass)

     int symclass;

{

  return symclass == 'U' || symclass == 'w' || symclass == 'v';

}

/*

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

bfd_symbol_info (symbol, ret)

     asymbol *symbol;

     symbol_info *ret;

{

  ret->type = bfd_decode_symclass (symbol);

  if (bfd_is_undefined_symclass (ret->type))

    ret->value = 0;

  else

    ret->value = symbol->value + symbol->section->vma;

  ret->name = symbol->name;

}

/*

FUNCTION

        bfd_copy_private_symbol_data

SYNOPSIS

        boolean bfd_copy_private_symbol_data(bfd *ibfd, asymbol *isym, bfd *obfd, asymbol *osym);

DESCRIPTION

        Copy private symbol information from @var{isym} in the BFD

        @var{ibfd} to the symbol @var{osym} in the BFD @var{obfd}.

        Return <<true>> on success, <<false>> on error.  Possible error

        returns are:

        o <<bfd_error_no_memory>> -

        Not enough memory exists to create private data for @var{osec}.

.#define bfd_copy_private_symbol_data(ibfd, isymbol, obfd, osymbol) \

.     BFD_SEND (obfd, _bfd_copy_private_symbol_data, \

.               (ibfd, isymbol, obfd, osymbol))

.

*/

/* The generic version of the function which returns mini symbols.

   This is used when the backend does not provide a more efficient

   version.  It just uses BFD asymbol structures as mini symbols.  */

long

_bfd_generic_read_minisymbols (abfd, dynamic, minisymsp, sizep)

     bfd *abfd;

     boolean dynamic;

     PTR *minisymsp;

     unsigned int *sizep;

{

  long storage;

  asymbol **syms = NULL;

  long symcount;

  if (dynamic)

    storage = bfd_get_dynamic_symtab_upper_bound (abfd);

  else

    storage = bfd_get_symtab_upper_bound (abfd);

  if (storage < 0)

    goto error_return;

  if (storage == 0)

    return 0;

  syms = (asymbol **) bfd_malloc ((bfd_size_type) storage);

  if (syms == NULL)

    goto error_return;

  if (dynamic)

    symcount = bfd_canonicalize_dynamic_symtab (abfd, syms);

  else

    symcount = bfd_canonicalize_symtab (abfd, syms);

  if (symcount < 0)

    goto error_return;

  *minisymsp = (PTR) syms;

  *sizep = sizeof (asymbol *);

  return symcount;

 error_return:

  bfd_set_error (bfd_error_no_symbols);

  if (syms != NULL)