text: /* cond.c - conditional assembly pseudo-ops, and .include
     Copyright 1990, 1991, 1992, 1993, 1995, 1997, 1998, 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.  */
  
  #include "as.h"
  #include "macro.h"
  
  #include "obstack.h"
  
  /* This is allocated to grow and shrink as .ifdef/.endif pairs are
     scanned.  */
  struct obstack cond_obstack;
  
  struct file_line {
    char *file;
    unsigned int line;
  };
  
  /* We push one of these structures for each .if, and pop it at the
     .endif.  */
  
  struct conditional_frame {
    /* The source file & line number of the "if".  */
    struct file_line if_file_line;
    /* The source file & line of the "else".  */
    struct file_line else_file_line;
    /* The previous conditional.  */
    struct conditional_frame *previous_cframe;
    /* Have we seen an else yet?  */
    int else_seen;
    /* Whether we are currently ignoring input.  */
    int ignoring;
    /* Whether a conditional at a higher level is ignoring input.
       Set also when a branch of an "if .. elseif .." tree has matched
       to prevent further matches.  */
    int dead_tree;
    /* Macro nesting level at which this conditional was created.  */
    int macro_nest;
  };
  
  static void initialize_cframe PARAMS ((struct conditional_frame *cframe));
  static char *get_mri_string PARAMS ((int, int *));
  
  static struct conditional_frame *current_cframe = NULL;
  
  /* Performs the .ifdef (test_defined == 1) and
     the .ifndef (test_defined == 0) pseudo op.  */
  
  void
  s_ifdef (test_defined)
       int test_defined;
  {
    /* Points to name of symbol.  */
    char *name;
    /* Points to symbol.  */
    symbolS *symbolP;
    struct conditional_frame cframe;
    char c;
  
    /* Leading whitespace is part of operand.  */
    SKIP_WHITESPACE ();
    name = input_line_pointer;
  
    if (!is_name_beginner (*name))
      {
        as_bad (_("invalid identifier for \".ifdef\""));
        obstack_1grow (&cond_obstack, 0);
        ignore_rest_of_line ();
        return;
      }
  
    c = get_symbol_end ();
    symbolP = symbol_find (name);
    *input_line_pointer = c;
  
    initialize_cframe (&cframe);
    
    if (cframe.dead_tree)
      cframe.ignoring = 1;
    else
      {
        int is_defined;
  
        /* Use the same definition of 'defined' as .equiv so that a symbol
  	 which has been referenced but not yet given a value/address is
  	 considered to be undefined.  */
        is_defined =
  	symbolP != NULL
  	&& S_IS_DEFINED (symbolP)
  	&& S_GET_SEGMENT (symbolP) != reg_section;
  
        cframe.ignoring = ! (test_defined ^ is_defined);
      }
  
    current_cframe = ((struct conditional_frame *)
  		    obstack_copy (&cond_obstack, &cframe,
  				  sizeof (cframe)));
  
    if (LISTING_SKIP_COND ()
        && cframe.ignoring
        && (cframe.previous_cframe == NULL
  	  || ! cframe.previous_cframe->ignoring))
      listing_list (2);
  
    demand_empty_rest_of_line ();
  }
  
  void
  s_if (arg)
       int arg;
  {
    expressionS operand;
    struct conditional_frame cframe;
    int t;
    char *stop = NULL;
    char stopc;
  
    if (flag_mri)
      stop = mri_comment_field (&stopc);
  
    /* Leading whitespace is part of operand.  */
    SKIP_WHITESPACE ();
  
    if (current_cframe != NULL && current_cframe->ignoring)
      {
        operand.X_add_number = 0;
        while (! is_end_of_line[(unsigned char) *input_line_pointer])
  	++input_line_pointer;
      }
    else
      {
        expression (&operand);
        if (operand.X_op != O_constant)
  	as_bad (_("non-constant expression in \".if\" statement"));
      }
  
    switch ((operatorT) arg)
      {
      case O_eq: t = operand.X_add_number == 0; break;
      case O_ne: t = operand.X_add_number != 0; break;
      case O_lt: t = operand.X_add_number < 0; break;
      case O_le: t = operand.X_add_number <= 0; break;
      case O_ge: t = operand.X_add_number >= 0; break;
      case O_gt: t = operand.X_add_number > 0; break;
      default:
        abort ();
        return;
      }
  
    /* If the above error is signaled, this will dispatch
       using an undefined result.  No big deal.  */
    initialize_cframe (&cframe);
    cframe.ignoring = cframe.dead_tree || ! t;
    current_cframe = ((struct conditional_frame *)
  		    obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
  
    if (LISTING_SKIP_COND ()
        && cframe.ignoring
        && (cframe.previous_cframe == NULL
  	  || ! cframe.previous_cframe->ignoring))
      listing_list (2);
  
    if (flag_mri)
      mri_comment_end (stop, stopc);
  
    demand_empty_rest_of_line ();
  }
  
  /* Get a string for the MRI IFC or IFNC pseudo-ops.  */
  
  static char *
  get_mri_string (terminator, len)
       int terminator;
       int *len;
  {
    char *ret;
    char *s;
  
    SKIP_WHITESPACE ();
    s = ret = input_line_pointer;
    if (*input_line_pointer == '\'')
      {
        ++s;
        ++input_line_pointer;
        while (! is_end_of_line[(unsigned char) *input_line_pointer])
  	{
  	  *s++ = *input_line_pointer++;
  	  if (s[-1] == '\'')
  	    {
  	      if (*input_line_pointer != '\'')
  		break;
  	      ++input_line_pointer;
  	    }
  	}
        SKIP_WHITESPACE ();
      }
    else
      {
        while (*input_line_pointer != terminator
  	     && ! is_end_of_line[(unsigned char) *input_line_pointer])
  	++input_line_pointer;
        s = input_line_pointer;
        while (s > ret && (s[-1] == ' ' || s[-1] == '\t'))
  	--s;
      }
  
    *len = s - ret;
    return ret;
  }
  
  /* The MRI IFC and IFNC pseudo-ops.  */
  
  void
  s_ifc (arg)
       int arg;
  {
    char *stop = NULL;
    char stopc;
    char *s1, *s2;
    int len1, len2;
    int res;
    struct conditional_frame cframe;
  
    if (flag_mri)
      stop = mri_comment_field (&stopc);
  
    s1 = get_mri_string (',', &len1);
  
    if (*input_line_pointer != ',')
      as_bad (_("bad format for ifc or ifnc"));
    else
      ++input_line_pointer;
  
    s2 = get_mri_string (';', &len2);
  
    res = len1 == len2 && strncmp (s1, s2, len1) == 0;
  
    initialize_cframe (&cframe);
    cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
    current_cframe = ((struct conditional_frame *)
  		    obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
  
    if (LISTING_SKIP_COND ()
        && cframe.ignoring
        && (cframe.previous_cframe == NULL
  	  || ! cframe.previous_cframe->ignoring))
      listing_list (2);
  
    if (flag_mri)
      mri_comment_end (stop, stopc);
  
    demand_empty_rest_of_line ();
  }
  
  void
  s_elseif (arg)
       int arg;
  {
    if (current_cframe == NULL)
      {
        as_bad (_("\".elseif\" without matching \".if\""));
      }
    else if (current_cframe->else_seen)
      {
        as_bad (_("\".elseif\" after \".else\""));
        as_bad_where (current_cframe->else_file_line.file,
  		    current_cframe->else_file_line.line,
  		    _("here is the previous \"else\""));
        as_bad_where (current_cframe->if_file_line.file,
  		    current_cframe->if_file_line.line,
  		    _("here is the previous \"if\""));
      }
    else
      {
        as_where (&current_cframe->else_file_line.file,
  		&current_cframe->else_file_line.line);
  
        current_cframe->dead_tree |= !current_cframe->ignoring;
        current_cframe->ignoring = current_cframe->dead_tree;
      }
  
    if (current_cframe == NULL || current_cframe->ignoring)
      {
        while (! is_end_of_line[(unsigned char) *input_line_pointer])
  	++input_line_pointer;
  
        if (current_cframe == NULL)
  	return;
      }
    else
      {
        expressionS operand;
        int t;
  
        /* Leading whitespace is part of operand.  */
        SKIP_WHITESPACE ();
  
        expression (&operand);
        if (operand.X_op != O_constant)
  	as_bad (_("non-constant expression in \".elseif\" statement"));
  
        switch ((operatorT) arg)
  	{
  	case O_eq: t = operand.X_add_number == 0; break;
  	case O_ne: t = operand.X_add_number != 0; break;
  	case O_lt: t = operand.X_add_number < 0; break;
  	case O_le: t = operand.X_add_number <= 0; break;
  	case O_ge: t = operand.X_add_number >= 0; break;
  	case O_gt: t = operand.X_add_number > 0; break;
  	default:
  	  abort ();
  	  return;
  	}
  
        current_cframe->ignoring = current_cframe->dead_tree || ! t;
      }
  
    if (LISTING_SKIP_COND ()
        && (current_cframe->previous_cframe == NULL
  	  || ! current_cframe->previous_cframe->ignoring))
      {
        if (! current_cframe->ignoring)
  	listing_list (1);
        else
  	listing_list (2);
      }
  
    demand_empty_rest_of_line ();
  }
  
  void
  s_endif (arg)
       int arg ATTRIBUTE_UNUSED;
  {
    struct conditional_frame *hold;
  
    if (current_cframe == NULL)
      {
        as_bad (_("\".endif\" without \".if\""));
      }
    else
      {
        if (LISTING_SKIP_COND ()
  	  && current_cframe->ignoring
  	  && (current_cframe->previous_cframe == NULL
  	      || ! current_cframe->previous_cframe->ignoring))
  	listing_list (1);
  
        hold = current_cframe;
        current_cframe = current_cframe->previous_cframe;
        obstack_free (&cond_obstack, hold);
      }				/* if one pop too many */
  
    if (flag_mri)
      {
        while (! is_end_of_line[(unsigned char) *input_line_pointer])
  	++input_line_pointer;
      }
  
    demand_empty_rest_of_line ();
  }
  
  void
  s_else (arg)
       int arg ATTRIBUTE_UNUSED;
  {
    if (current_cframe == NULL)
      {
        as_bad (_("\".else\" without matching \".if\""));
      }
    else if (current_cframe->else_seen)
      {
        as_bad (_("duplicate \"else\""));
        as_bad_where (current_cframe->else_file_line.file,
  		    current_cframe->else_file_line.line,
  		    _("here is the previous \"else\""));
        as_bad_where (current_cframe->if_file_line.file,
  		    current_cframe->if_file_line.line,
  		    _("here is the previous \"if\""));
      }
    else
      {
        as_where (&current_cframe->else_file_line.file,
  		&current_cframe->else_file_line.line);
  
        current_cframe->ignoring =
  	current_cframe->dead_tree | !current_cframe->ignoring;
  
        if (LISTING_SKIP_COND ()
  	  && (current_cframe->previous_cframe == NULL
  	      || ! current_cframe->previous_cframe->ignoring))
  	{
  	  if (! current_cframe->ignoring)
  	    listing_list (1);
  	  else
  	    listing_list (2);
  	}
  
        current_cframe->else_seen = 1;
      }
  
    if (flag_mri)
      {
        while (! is_end_of_line[(unsigned char) *input_line_pointer])
  	++input_line_pointer;
      }
  
    demand_empty_rest_of_line ();
  }
  
  void
  s_ifeqs (arg)
       int arg;
  {
    char *s1, *s2;
    int len1, len2;
    int res;
    struct conditional_frame cframe;
  
    s1 = demand_copy_C_string (&len1);
  
    SKIP_WHITESPACE ();
    if (*input_line_pointer != ',')
      {
        as_bad (_(".ifeqs syntax error"));
        ignore_rest_of_line ();
        return;
      }
  
    ++input_line_pointer;
  
    s2 = demand_copy_C_string (&len2);
  
    res = len1 == len2 && strncmp (s1, s2, len1) == 0;
  
    initialize_cframe (&cframe);
    cframe.ignoring = cframe.dead_tree || ! (res ^ arg);
    current_cframe = ((struct conditional_frame *)
  		    obstack_copy (&cond_obstack, &cframe, sizeof (cframe)));
  
    if (LISTING_SKIP_COND ()
        && cframe.ignoring
        && (cframe.previous_cframe == NULL
  	  || ! cframe.previous_cframe->ignoring))
      listing_list (2);
  
    demand_empty_rest_of_line ();
  }
  
  int
  ignore_input ()
  {
    char *s;
  
    s = input_line_pointer;
  
    if (NO_PSEUDO_DOT || flag_m68k_mri)
      {
        if (s[-1] != '.')
  	--s;
      }
    else
      {
        if (s[-1] != '.')
  	return (current_cframe != NULL) && (current_cframe->ignoring);
      }
  
    /* We cannot ignore certain pseudo ops.  */
    if (((s[0] == 'i'
  	|| s[0] == 'I')
         && (!strncasecmp (s, "if", 2)
  	   || !strncasecmp (s, "ifdef", 5)
  	   || !strncasecmp (s, "ifndef", 6)))
        || ((s[0] == 'e'
  	   || s[0] == 'E')
  	  && (!strncasecmp (s, "else", 4)
  	      || !strncasecmp (s, "endif", 5)
  	      || !strncasecmp (s, "endc", 4))))
      return 0;
  
    return (current_cframe != NULL) && (current_cframe->ignoring);
  }
  
  static void
  initialize_cframe (cframe)
       struct conditional_frame *cframe;
  {
    memset (cframe, 0, sizeof (*cframe));
    as_where (&cframe->if_file_line.file,
  	    &cframe->if_file_line.line);
    cframe->previous_cframe = current_cframe;
    cframe->dead_tree = current_cframe != NULL && current_cframe->ignoring;
    cframe->macro_nest = macro_nest;
  }
  
  /* Give an error if a conditional is unterminated inside a macro or
     the assembly as a whole.  If NEST is non negative, we are being
     called because of the end of a macro expansion.  If NEST is
     negative, we are being called at the of the input files.  */
  
  void
  cond_finish_check (nest)
       int nest;
  {
    if (current_cframe != NULL && current_cframe->macro_nest >= nest)
      {
        if (nest >= 0)
  	as_bad (_("end of macro inside conditional"));
        else
  	as_bad (_("end of file inside conditional"));
        as_bad_where (current_cframe->if_file_line.file,
  		    current_cframe->if_file_line.line,
  		    _("here is the start of the unterminated conditional"));
        if (current_cframe->else_seen)
  	as_bad_where (current_cframe->else_file_line.file,
  		      current_cframe->else_file_line.line,
  		      _("here is the \"else\" of the unterminated conditional"));
      }
  }
  
  /* This function is called when we exit out of a macro.  We assume
     that any conditionals which began within the macro are correctly
     nested, and just pop them off the stack.  */
  
  void
  cond_exit_macro (nest)
       int nest;
  {
    while (current_cframe != NULL && current_cframe->macro_nest >= nest)
      {
        struct conditional_frame *hold;
  
        hold = current_cframe;
        current_cframe = current_cframe->previous_cframe;
        obstack_free (&cond_obstack, hold);
      }
  }
  