obj-aout.c

来自「基于4个mips核的noc设计」· C语言 代码 · 共 759 行 · 第 1/2 页

/* a.out object file format
   Copyright 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1999, 2000, 2001
   Free Software Foundation, Inc.

This file is part of GAS, the GNU Assembler.

GAS 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,
or (at your option) any later version.

GAS 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 GAS; see the file COPYING.  If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.  */

#define OBJ_HEADER "obj-aout.h"

#include "as.h"
#ifdef BFD_ASSEMBLER
#undef NO_RELOC
#include "aout/aout64.h"
#endif
#include "obstack.h"

#ifndef BFD_ASSEMBLER
/* in: segT   out: N_TYPE bits */
const short seg_N_TYPE[] =
{
  N_ABS,
  N_TEXT,
  N_DATA,
  N_BSS,
  N_UNDF,			/* unknown */
  N_UNDF,			/* error */
  N_UNDF,			/* expression */
  N_UNDF,			/* debug */
  N_UNDF,			/* ntv */
  N_UNDF,			/* ptv */
  N_REGISTER,			/* register */
};

const segT N_TYPE_seg[N_TYPE + 2] =
{				/* N_TYPE == 0x1E = 32-2 */
  SEG_UNKNOWN,			/* N_UNDF == 0 */
  SEG_GOOF,
  SEG_ABSOLUTE,			/* N_ABS == 2 */
  SEG_GOOF,
  SEG_TEXT,			/* N_TEXT == 4 */
  SEG_GOOF,
  SEG_DATA,			/* N_DATA == 6 */
  SEG_GOOF,
  SEG_BSS,			/* N_BSS == 8 */
  SEG_GOOF,
  SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
  SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
  SEG_GOOF, SEG_GOOF, SEG_GOOF, SEG_GOOF,
  SEG_REGISTER,			/* dummy N_REGISTER for regs = 30 */
  SEG_GOOF,
};
#endif

static void obj_aout_line PARAMS ((int));
static void obj_aout_weak PARAMS ((int));
static void obj_aout_type PARAMS ((int));

const pseudo_typeS aout_pseudo_table[] =
{
  {"line", obj_aout_line, 0},	/* source code line number */
  {"ln", obj_aout_line, 0},	/* coff line number that we use anyway */

  {"weak", obj_aout_weak, 0},	/* mark symbol as weak.  */

  {"type", obj_aout_type, 0},

  /* coff debug pseudos (ignored) */
  {"def", s_ignore, 0},
  {"dim", s_ignore, 0},
  {"endef", s_ignore, 0},
  {"ident", s_ignore, 0},
  {"line", s_ignore, 0},
  {"ln", s_ignore, 0},
  {"scl", s_ignore, 0},
  {"size", s_ignore, 0},
  {"tag", s_ignore, 0},
  {"val", s_ignore, 0},
  {"version", s_ignore, 0},

  {"optim", s_ignore, 0},	/* For sun386i cc (?) */

  /* other stuff */
  {"ABORT", s_abort, 0},

  {NULL, NULL, 0}		/* end sentinel */
};				/* aout_pseudo_table */

#ifdef BFD_ASSEMBLER

void
obj_aout_frob_symbol (sym, punt)
     symbolS *sym;
     int *punt ATTRIBUTE_UNUSED;
{
  flagword flags;
  asection *sec;
  int desc, type, other;

  flags = symbol_get_bfdsym (sym)->flags;
  desc = aout_symbol (symbol_get_bfdsym (sym))->desc;
  type = aout_symbol (symbol_get_bfdsym (sym))->type;
  other = aout_symbol (symbol_get_bfdsym (sym))->other;
  sec = S_GET_SEGMENT (sym);

  /* Only frob simple symbols this way right now.  */
  if (! (type & ~ (N_TYPE | N_EXT)))
    {
      if (type == (N_UNDF | N_EXT)
	  && sec == &bfd_abs_section)
	{
	  sec = bfd_und_section_ptr;
	  S_SET_SEGMENT (sym, sec);
	}

      if ((type & N_TYPE) != N_INDR
	  && (type & N_TYPE) != N_SETA
	  && (type & N_TYPE) != N_SETT
	  && (type & N_TYPE) != N_SETD
	  && (type & N_TYPE) != N_SETB
	  && type != N_WARNING
	  && (sec == &bfd_abs_section
	      || sec == &bfd_und_section))
	return;
      if (flags & BSF_EXPORT)
	type |= N_EXT;

      switch (type & N_TYPE)
	{
	case N_SETA:
	case N_SETT:
	case N_SETD:
	case N_SETB:
	  /* Set the debugging flag for constructor symbols so that
	     BFD leaves them alone.  */
	  symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;

	  /* You can't put a common symbol in a set.  The way a set
	     element works is that the symbol has a definition and a
	     name, and the linker adds the definition to the set of
	     that name.  That does not work for a common symbol,
	     because the linker can't tell which common symbol the
	     user means.  FIXME: Using as_bad here may be
	     inappropriate, since the user may want to force a
	     particular type without regard to the semantics of sets;
	     on the other hand, we certainly don't want anybody to be
	     mislead into thinking that their code will work.  */
	  if (S_IS_COMMON (sym))
	    as_bad (_("Attempt to put a common symbol into set %s"),
		    S_GET_NAME (sym));
	  /* Similarly, you can't put an undefined symbol in a set.  */
	  else if (! S_IS_DEFINED (sym))
	    as_bad (_("Attempt to put an undefined symbol into set %s"),
		    S_GET_NAME (sym));

	  break;
	case N_INDR:
	  /* Put indirect symbols in the indirect section.  */
	  S_SET_SEGMENT (sym, bfd_ind_section_ptr);
	  symbol_get_bfdsym (sym)->flags |= BSF_INDIRECT;
	  if (type & N_EXT)
	    {
	      symbol_get_bfdsym (sym)->flags |= BSF_EXPORT;
	      symbol_get_bfdsym (sym)->flags &=~ BSF_LOCAL;
	    }
	  break;
	case N_WARNING:
	  /* Mark warning symbols.  */
	  symbol_get_bfdsym (sym)->flags |= BSF_WARNING;
	  break;
	}
    }
  else
    {
      symbol_get_bfdsym (sym)->flags |= BSF_DEBUGGING;
    }

  aout_symbol (symbol_get_bfdsym (sym))->type = type;

  /* Double check weak symbols.  */
  if (S_IS_WEAK (sym))
    {
      if (S_IS_COMMON (sym))
	as_bad (_("Symbol `%s' can not be both weak and common"),
		S_GET_NAME (sym));
    }
}

void
obj_aout_frob_file ()
{
  /* Relocation processing may require knowing the VMAs of the sections.
     Since writing to a section will cause the BFD back end to compute the
     VMAs, fake it out here....  */
  bfd_byte b = 0;
  boolean x = true;
  if (bfd_section_size (stdoutput, text_section) != 0)
    {
      x = bfd_set_section_contents (stdoutput, text_section, &b, (file_ptr) 0,
				    (bfd_size_type) 1);
    }
  else if (bfd_section_size (stdoutput, data_section) != 0)
    {
      x = bfd_set_section_contents (stdoutput, data_section, &b, (file_ptr) 0,
				    (bfd_size_type) 1);
    }
  assert (x == true);
}

#else /* ! BFD_ASSEMBLER */

/* Relocation.  */

/*
 *		emit_relocations()
 *
 * Crawl along a fixS chain. Emit the segment's relocations.
 */
void
obj_emit_relocations (where, fixP, segment_address_in_file)
     char **where;
     fixS *fixP;		/* Fixup chain for this segment.  */
     relax_addressT segment_address_in_file;
{
  for (; fixP; fixP = fixP->fx_next)
    if (fixP->fx_done == 0)
      {
	symbolS *sym;

	sym = fixP->fx_addsy;
	while (sym->sy_value.X_op == O_symbol
	       && (! S_IS_DEFINED (sym) || S_IS_COMMON (sym)))
	  sym = sym->sy_value.X_add_symbol;
	fixP->fx_addsy = sym;

	if (! sym->sy_resolved && ! S_IS_DEFINED (sym))
	  {
	    char *file;
	    unsigned int line;

	    if (expr_symbol_where (sym, &file, &line))
	      as_bad_where (file, line, _("unresolved relocation"));
	    else
	      as_bad (_("bad relocation: symbol `%s' not in symbol table"),
		      S_GET_NAME (sym));
	  }

	tc_aout_fix_to_chars (*where, fixP, segment_address_in_file);
	*where += md_reloc_size;
      }
}

#ifndef obj_header_append
/* Aout file generation & utilities */
void
obj_header_append (where, headers)
     char **where;
     object_headers *headers;
{
  tc_headers_hook (headers);

#ifdef CROSS_COMPILE
  md_number_to_chars (*where, headers->header.a_info, sizeof (headers->header.a_info));
  *where += sizeof (headers->header.a_info);
  md_number_to_chars (*where, headers->header.a_text, sizeof (headers->header.a_text));
  *where += sizeof (headers->header.a_text);
  md_number_to_chars (*where, headers->header.a_data, sizeof (headers->header.a_data));
  *where += sizeof (headers->header.a_data);
  md_number_to_chars (*where, headers->header.a_bss, sizeof (headers->header.a_bss));
  *where += sizeof (headers->header.a_bss);
  md_number_to_chars (*where, headers->header.a_syms, sizeof (headers->header.a_syms));
  *where += sizeof (headers->header.a_syms);
  md_number_to_chars (*where, headers->header.a_entry, sizeof (headers->header.a_entry));
  *where += sizeof (headers->header.a_entry);
  md_number_to_chars (*where, headers->header.a_trsize, sizeof (headers->header.a_trsize));
  *where += sizeof (headers->header.a_trsize);
  md_number_to_chars (*where, headers->header.a_drsize, sizeof (headers->header.a_drsize));
  *where += sizeof (headers->header.a_drsize);

#else /* CROSS_COMPILE */

  append (where, (char *) &headers->header, sizeof (headers->header));
#endif /* CROSS_COMPILE */

}
#endif /* ! defined (obj_header_append) */

void
obj_symbol_to_chars (where, symbolP)
     char **where;
     symbolS *symbolP;
{
  md_number_to_chars ((char *) &(S_GET_OFFSET (symbolP)), S_GET_OFFSET (symbolP), sizeof (S_GET_OFFSET (symbolP)));
  md_number_to_chars ((char *) &(S_GET_DESC (symbolP)), S_GET_DESC (symbolP), sizeof (S_GET_DESC (symbolP)));
  md_number_to_chars ((char *) &(symbolP->sy_symbol.n_value), S_GET_VALUE (symbolP), sizeof (symbolP->sy_symbol.n_value));

  append (where, (char *) &symbolP->sy_symbol, sizeof (obj_symbol_type));
}

void
obj_emit_symbols (where, symbol_rootP)
     char **where;
     symbolS *symbol_rootP;
{
  symbolS *symbolP;

  /* Emit all symbols left in the symbol chain.  */
  for (symbolP = symbol_rootP; symbolP; symbolP = symbol_next (symbolP))
    {
      /* Used to save the offset of the name. It is used to point
	 to the string in memory but must be a file offset.  */
      register char *temp;

      temp = S_GET_NAME (symbolP);
      S_SET_OFFSET (symbolP, symbolP->sy_name_offset);

      /* Any symbol still undefined and is not a dbg symbol is made N_EXT.  */
      if (!S_IS_DEBUG (symbolP) && !S_IS_DEFINED (symbolP))
	S_SET_EXTERNAL (symbolP);

      /* Adjust the type of a weak symbol.  */
      if (S_GET_WEAK (symbolP))
	{
	  switch (S_GET_TYPE (symbolP))
	    {
	    case N_UNDF: S_SET_TYPE (symbolP, N_WEAKU); break;
	    case N_ABS:	 S_SET_TYPE (symbolP, N_WEAKA); break;
	    case N_TEXT: S_SET_TYPE (symbolP, N_WEAKT); break;
	    case N_DATA: S_SET_TYPE (symbolP, N_WEAKD); break;
	    case N_BSS:  S_SET_TYPE (symbolP, N_WEAKB); break;
	    default: as_bad (_("%s: bad type for weak symbol"), temp); break;
	    }
	}

      obj_symbol_to_chars (where, symbolP);
      S_SET_NAME (symbolP, temp);
    }
}

#endif /* ! BFD_ASSEMBLER */

static void
obj_aout_line (ignore)
     int ignore ATTRIBUTE_UNUSED;
{
  /* Assume delimiter is part of expression.
     BSD4.2 as fails with delightful bug, so we
     are not being incompatible here.  */
  new_logical_line ((char *) NULL, (int) (get_absolute_expression ()));
  demand_empty_rest_of_line ();
}				/* obj_aout_line() */

/* Handle .weak.  This is a GNU extension.  */

static void
obj_aout_weak (ignore)
     int ignore ATTRIBUTE_UNUSED;
{
  char *name;
  int c;
  symbolS *symbolP;

  do
    {
      name = input_line_pointer;
      c = get_symbol_end ();
      symbolP = symbol_find_or_make (name);