binutils-gdb/gas/stabs.c

/* Generic stabs parsing for gas.
   Copyright (C) 1989, 1990, 1991, 1993 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. */

#include "as.h"
#include "libiberty.h"
#include "obstack.h"
#include "subsegs.h"

/* We need this, despite the apparent object format dependency, since
   it defines stab types, which all object formats can use now. */

#include "aout/stab_gnu.h"

/* Allow backends to override the names used for the stab sections.  */
#ifndef STAB_SECTION_NAME
#define STAB_SECTION_NAME ".stab"
#endif

#ifndef STAB_STRING_SECTION_NAME
#define STAB_STRING_SECTION_NAME ".stabstr"
#endif

/*
 * Handle .stabX directives, which used to be open-coded.
 * So much creeping featurism overloaded the semantics that we decided
 * to put all .stabX thinking in one place. Here.
 *
 * We try to make any .stabX directive legal. Other people's AS will often
 * do assembly-time consistency checks: eg assigning meaning to n_type bits
 * and "protecting" you from setting them to certain values. (They also zero
 * certain bits before emitting symbols. Tut tut.)
 *
 * If an expression is not absolute we either gripe or use the relocation
 * information. Other people's assemblers silently forget information they
 * don't need and invent information they need that you didn't supply.
 */

/*
 * Build a string dictionary entry for a .stabX symbol.
 * The symbol is added to the .<secname>str section.
 */

#ifndef SEPARATE_STAB_SECTIONS
#define SEPARATE_STAB_SECTIONS 0
#endif

unsigned int
get_stab_string_offset (string, stabstr_secname)
     const char *string;
     const char *stabstr_secname;
{
  unsigned int length;
  unsigned int retval;

  if (! SEPARATE_STAB_SECTIONS)
    abort ();

  retval = 0;
  length = strlen (string);
  if (length > 0)
    {				/* Ordinary case. */
      segT save_seg;
      subsegT save_subseg;
      segT seg;
      char *p;

      save_seg = now_seg;
      save_subseg = now_subseg;

      /* Create the stab string section.  */
      seg = subseg_new (stabstr_secname, 0);

      retval = seg_info (seg)->stabu.stab_string_size;
      if (retval <= 0)
	{
	  /* Make sure the first string is empty.  */
	  p = frag_more (1);
	  *p = 0;
	  retval = seg_info (seg)->stabu.stab_string_size = 1;
#ifdef BFD_ASSEMBLER
	  bfd_set_section_flags (stdoutput, seg, SEC_READONLY | SEC_DEBUGGING);
	  if (seg->name == stabstr_secname)
	    seg->name = xstrdup (stabstr_secname);
#endif
	}

      p = frag_more (length + 1);
      strcpy (p, string);

      seg_info (seg)->stabu.stab_string_size += length + 1;

      subseg_set (save_seg, save_subseg);
    }

  return retval;
}

#ifdef AOUT_STABS
#ifndef OBJ_PROCESS_STAB
#define OBJ_PROCESS_STAB(SEG,W,S,T,O,D)	aout_process_stab(W,S,T,O,D)
#endif

static void
aout_process_stab (what, string, type, other, desc)
     int what;
     const char *string;
     int type, other, desc;
{
  /* Put the stab information in the symbol table.  */
  symbolS *symbol;

  /* Create the symbol now, but only insert it into the symbol chain
     after any symbols mentioned in the value expression get into the
     symbol chain.  This is to avoid "continuation symbols" (where one
     ends in "\" and the debug info is continued in the next .stabs
     directive) from being separated by other random symbols.  */
  symbol = symbol_create (string, undefined_section, 0,
			  (struct frag *) NULL);
  if (what == 's' || what == 'n')
    {
      /* Pick up the value from the input line.  */
      symbol->sy_frag = &zero_address_frag;
      pseudo_set (symbol);
    }
  else
    {
      /* .stabd sets the name to NULL.  Why?  */
      S_SET_NAME (symbol, NULL);
      symbol->sy_frag = frag_now;
      S_SET_VALUE (symbol, (valueT) frag_now_fix ());
    }

  symbol_append (symbol, symbol_lastP, &symbol_rootP, &symbol_lastP);

  S_SET_TYPE (symbol, type);
  S_SET_OTHER (symbol, other);
  S_SET_DESC (symbol, desc);
}
#endif

/* This can handle different kinds of stabs (s,n,d) and different
   kinds of stab sections. */

static void 
s_stab_generic (what, stab_secname, stabstr_secname)
     int what;
     char *stab_secname;
     char *stabstr_secname;
{
  long longint;
  char *string;
  int type;
  int other;
  int desc;

  /* The general format is:
     .stabs "STRING",TYPE,OTHER,DESC,VALUE
     .stabn TYPE,OTHER,DESC,VALUE
     .stabd TYPE,OTHER,DESC
     At this point input_line_pointer points after the pseudo-op and
     any trailing whitespace.  The argument what is one of 's', 'n' or
     'd' indicating which type of .stab this is.  */

  if (what != 's')
    string = "";
  else
    {
      int length;

      string = demand_copy_C_string (&length);
      SKIP_WHITESPACE ();
      if (*input_line_pointer == ',')
	input_line_pointer++;
      else
	{
	  as_warn (".stabs: Missing comma");
	  ignore_rest_of_line ();
	  return;
	}
    }

  if (get_absolute_expression_and_terminator (&longint) != ',')
    {
      as_warn (".stab%c: Missing comma", what);
      ignore_rest_of_line ();
      return;
    }
  type = longint;

  if (get_absolute_expression_and_terminator (&longint) != ',')
    {
      as_warn (".stab%c: Missing comma", what);
      ignore_rest_of_line ();
      return;
    }
  other = longint;

  desc = get_absolute_expression ();
  if (what == 's' || what == 'n')
    {
      if (*input_line_pointer != ',')
	{
	  as_warn (".stab%c: Missing comma", what);
	  ignore_rest_of_line ();
	  return;
	}
      input_line_pointer++;
      SKIP_WHITESPACE ();
    }

#ifdef TC_PPC
#ifdef OBJ_ELF
  /* Solaris on PowerPC has decided that .stabd takes 4 arguments, so emulate it.  */
  else if (what == 'd')
    {
      char *save_location = input_line_pointer;

      SKIP_WHITESPACE ();
      if (*input_line_pointer == ',')
	{
	  int dummy;

	  input_line_pointer++;
	  SKIP_WHITESPACE ();

	  dummy = get_absolute_expression ();
	  if (dummy != 0)
	    {
	      as_warn (".stabd: Fourth field must be 0");
	      ignore_rest_of_line ();
	      return;
	    }
	  SKIP_WHITESPACE ();
	}
      else
	input_line_pointer = save_location;
    }
#endif /* OBJ_ELF */
#endif /* TC_PPC */

#ifndef NO_LISTING
  if (listing)
    {
      switch (type)
	{
	case N_SLINE:
	  listing_source_line ((unsigned int) desc);
	  break;
	case N_SO:
	case N_SOL:
	  listing_source_file (string);
	  break;
	}
    }
#endif /* ! NO_LISTING */

  /* We have now gathered the type, other, and desc information.  For
     .stabs or .stabn, input_line_pointer is now pointing at the
     value.  */

  if (SEPARATE_STAB_SECTIONS)
    /* Output the stab information in a separate section.  This is used
       at least for COFF and ELF.  */
    {
      segT saved_seg = now_seg;
      subsegT saved_subseg = now_subseg;
      fragS *saved_frag = frag_now;
      valueT dot;
      segT seg;
      unsigned int stroff;
      char *p;

      static segT cached_sec;
      static char *cached_secname;

      dot = frag_now_fix ();

      if (cached_secname && !strcmp (cached_secname, stab_secname))
	{
	  seg = cached_sec;
	  subseg_set (seg, 0);
	}
      else
	{
	  seg = subseg_new (stab_secname, 0);
	  if (cached_secname)
	    free (cached_secname);
	  cached_secname = xstrdup (stab_secname);
	  cached_sec = seg;
	}

      if (! seg_info (seg)->hadone)
	{
#ifdef BFD_ASSEMBLER
	  bfd_set_section_flags (stdoutput, seg,
				 SEC_READONLY | SEC_RELOC | SEC_DEBUGGING);
#endif
#ifdef INIT_STAB_SECTION
	  INIT_STAB_SECTION (seg);
#endif
	  seg_info (seg)->hadone = 1;
	}

      stroff = get_stab_string_offset (string, stabstr_secname);
      if (what == 's')
	{
	  /* release the string */
	  obstack_free (&notes, string);
	}

      /* At least for now, stabs in a special stab section are always
	 output as 12 byte blocks of information.  */
      p = frag_more (8);
      md_number_to_chars (p, (valueT) stroff, 4);
      md_number_to_chars (p + 4, (valueT) type, 1);
      md_number_to_chars (p + 5, (valueT) other, 1);
      md_number_to_chars (p + 6, (valueT) desc, 2);

      if (what == 's' || what == 'n')
	{
	  /* Pick up the value from the input line.  */
	  cons (4);
	  input_line_pointer--;
	}
      else
	{
	  const char *fake;
	  symbolS *symbol;
	  expressionS exp;

	  /* Arrange for a value representing the current location.  */
	  fake = FAKE_LABEL_NAME;
	  symbol = symbol_new (fake, saved_seg, dot, saved_frag);

	  exp.X_op = O_symbol;
	  exp.X_add_symbol = symbol;
	  exp.X_add_number = 0;

	  emit_expr (&exp, 4);
	}

#ifdef OBJ_PROCESS_STAB
      OBJ_PROCESS_STAB (seg, what, string, type, other, desc);
#endif

      subseg_set (saved_seg, saved_subseg);
    }
  else
    {
#ifdef OBJ_PROCESS_STAB
      OBJ_PROCESS_STAB (0, what, string, type, other, desc);
#else
      abort ();
#endif
    }

  demand_empty_rest_of_line ();
}

/* Regular stab directive. */

void
s_stab (what)
     int what;
{
  s_stab_generic (what, STAB_SECTION_NAME, STAB_STRING_SECTION_NAME);
}

/* "Extended stabs", used in Solaris only now. */

void
s_xstab (what)
     int what;
{
  int length;
  char *stab_secname, *stabstr_secname;
  static char *saved_secname, *saved_strsecname;

  /* @@ MEMORY LEAK: This allocates a copy of the string, but in most
     cases it will be the same string, so we could release the storage
     back to the obstack it came from.  */
  stab_secname = demand_copy_C_string (&length);
  SKIP_WHITESPACE ();
  if (*input_line_pointer == ',')
    input_line_pointer++;
  else
    {
      as_bad ("comma missing in .xstabs");
      ignore_rest_of_line ();
      return;
    }

  /* To get the name of the stab string section, simply add "str" to
     the stab section name.  */
  if (saved_secname == 0 || strcmp (saved_secname, stab_secname))
    {
      stabstr_secname = (char *) xmalloc (strlen (stab_secname) + 4);
      strcpy (stabstr_secname, stab_secname);
      strcat (stabstr_secname, "str");
      if (saved_secname)
	{
	  free (saved_secname);
	  free (saved_strsecname);
	}
      saved_secname = stab_secname;
      saved_strsecname = stabstr_secname;
    }
  s_stab_generic (what, saved_secname, saved_strsecname);
}

#ifdef S_SET_DESC

/* Frob invented at RMS' request. Set the n_desc of a symbol.  */

void 
s_desc (ignore)
     int ignore;
{
  char *name;
  char c;
  char *p;
  symbolS *symbolP;
  int temp;

  name = input_line_pointer;
  c = get_symbol_end ();
  p = input_line_pointer;
  *p = c;
  SKIP_WHITESPACE ();
  if (*input_line_pointer != ',')
    {
      *p = 0;
      as_bad ("Expected comma after name \"%s\"", name);
      *p = c;
      ignore_rest_of_line ();
    }
  else
    {
      input_line_pointer++;
      temp = get_absolute_expression ();
      *p = 0;
      symbolP = symbol_find_or_make (name);
      *p = c;
      S_SET_DESC (symbolP, temp);
    }
  demand_empty_rest_of_line ();
}				/* s_desc() */

#endif /* defined (S_SET_DESC) */