old-cross-binutils/bfd/syms.c
Ian Lance Taylor 0ee75d02e5 * syms.c (BSF_DYNAMIC): New symbol flag.
(bfd_print_symbol_vandf): Print it.
	* bfd-in2.h: Rebuilt.
	* libaout.h (struct aout_backend_data): New read_dynamic_symbols
	and read_dynamic_relocs fields.
	(struct aoutdata): New dynamic_info field.
	(obj_aout_dynamic_info): New accessor macro.
	* sunos.c (struct sunos_dynamic_info): New structure.
	(sunos_read_dynamic_info, MY(read_dynamic_symbols),
	MY(read_dynamic_relocs)): New functions to read dynamic symbols
	and relocs.
	* aoutx.h (NAME(aout,some_aout_object_p)): If the object is
	dynamically linked, set SEC_RELOC for both the .text and .data
	sections.
	(translate_from_native_sym_flags): Don't set BSF_LOCAL for an
	undefined symbol.
	(translate_symbol_table): New function, split out of
	slurp_symbol_table; set the BSF_DYNAMIC flag appropriately.
	(NAME(aout,slurp_symbol_table)): Read dynamic symbols, if any.
	(NAME(aout,slurp_reloc_table)): Read dynamic relocs, if any.
	(NAME(aout,get_reloc_upper_bound)): Include dynamic reloc count in
	return value.
	* aoutf1.h (NAME(aout,sunos4_write_object_contents)): Don't write
	out dynamic symbols or relocs against reloc symbols, since they
	are already in the .text section and we wouldn't know where to
	write them anyhow.
	(sunos4_aout_backend): Initialize read_dynamic_symbols and
	read_dynamic_relocs fields.
	* aout-target.h (MY(backend_data)): Initialize
	read_dynamic_symbols and read_dynamic_relocs fields.
1994-01-21 06:29:21 +00:00

536 lines
14 KiB
C

/* Generic symbol-table support for the BFD library.
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.
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., 675 Mass Ave, Cambridge, MA 02139, 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::
@* 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:
| unsigned int storage_needed;
| asymbol **symbol_table;
| unsigned int number_of_symbols;
| unsigned int i;
|
| storage_needed = get_symtab_upper_bound (abfd);
|
| if (storage_needed == 0) {
| return ;
| }
| symbol_table = (asymbol **) bfd_xmalloc (storage_needed);
| ...
| number_of_symbols =
| bfd_canonicalize_symtab (abfd, symbol_table);
|
| for (i = 0; i < number_of_symbols; i++) {
| process_symbol (symbol_table[i]);
| }
All storage for the symbols themselves is in an obstack
connected to the BFD; it is freed when the BFD is closed.
INODE
Writing Symbols, typedef asymbol, 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.
*/
/*
DOCDD
INODE
typedef asymbol, symbol handling functions, Writing 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. *}
.#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. 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 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 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
.
. 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. This is being phased out in favour
. of making this a union. *}
. PTR udata;
.
.} asymbol;
*/
#include "bfd.h"
#include "sysdep.h"
#include "libbfd.h"
#include "aout/stab_gnu.h"
/*
DOCDD
INODE
symbol handling functions, , typedef asymbol, Symbols
SUBSECTION
Symbol handling functions
*/
/*
FUNCTION
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.
.#define get_symtab_upper_bound(abfd) \
. BFD_SEND (abfd, _get_symtab_upper_bound, (abfd))
*/
/*
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_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(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,(arg, symbol),
PTR arg AND
asymbol *symbol)
{
FILE *file = (FILE *) arg;
flagword type = symbol->flags;
if (symbol->section != (asection *)NULL)
{
fprintf_vma(file, symbol->value+symbol->section->vma);
}
else
{
fprintf_vma(file, symbol->value);
}
/* This presumes that a symbol can not be both BSF_DEBUGGING and
BSF_DYNAMIC. */
fprintf(file," %c%c%c%c%c%c%c",
(type & BSF_LOCAL) ? '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' : ' ');
}
/*
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_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 character corresponding to the symbol
class of @var{symbol}, or '?' for an unknown class.
SYNOPSIS
int bfd_decode_symclass(asymbol *symbol);
*/
int
DEFUN(bfd_decode_symclass,(symbol),
asymbol *symbol)
{
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';
N_SETA: 'l';
N_SETT: 'x';
N_SETD: 'z';
N_SETB: 's';
N_INDR: 'i';
*/
}
/*
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();
}