conflicts.c

Bison语法分析器

      /* If invoked under the name `yacc', use the output format
	 specified by POSIX.  */
      fprintf(stderr, _("conflicts: "));
      if (src_total > 0)
	fprintf(stderr, _(" %d shift/reduce"), src_total);
      if (src_total > 0 && rrc_total > 0)
	fprintf(stderr, ",");
      if (rrc_total > 0)
	fprintf(stderr, _(" %d reduce/reduce"), rrc_total);
      putc('\n', stderr);
    }
  else
    {
      fprintf(stderr, _("%s contains"), infile);

      if (src_total == 1)
	fprintf(stderr, _(" 1 shift/reduce conflict"));
      else if (src_total > 1)
	fprintf(stderr, _(" %d shift/reduce conflicts"), src_total);

      if (src_total > 0 && rrc_total > 0)
	fprintf(stderr, _(" and"));

      if (rrc_total == 1)
	fprintf(stderr, _(" 1 reduce/reduce conflict"));
      else if (rrc_total > 1)
	fprintf(stderr, _(" %d reduce/reduce conflicts"), rrc_total);

      putc('.', stderr);
      putc('\n', stderr);
    }
}


void
count_sr_conflicts (int state)
{
  register int i;
  register int k;
  register int mask;
  register shifts *shiftp;
  register unsigned *fp1;
  register unsigned *fp2;
  register unsigned *fp3;
  register int symbol;

  src_count = 0;

  shiftp = shift_table[state];
  if (!shiftp) return;

  for (i = 0; i < tokensetsize; i++)
    {
      shiftset[i] = 0;
      lookaheadset[i] = 0;
    }

  k = shiftp->nshifts;
  for (i = 0; i < k; i++)
    {
      if (! shiftp->shifts[i]) continue;
      symbol = accessing_symbol[shiftp->shifts[i]];
      if (ISVAR(symbol)) break;
      SETBIT(shiftset, symbol);
    }

  k = lookaheads[state + 1];
  fp3 = lookaheadset + tokensetsize;

  for (i = lookaheads[state]; i < k; i++)
    {
      fp1 = LA + i * tokensetsize;
      fp2 = lookaheadset;

      while (fp2 < fp3)
	*fp2++ |= *fp1++;
    }

  fp1 = shiftset;
  fp2 = lookaheadset;

  while (fp2 < fp3)
    *fp2++ &= *fp1++;

  mask = 1;
  fp2 = lookaheadset;
  for (i = 0; i < ntokens; i++)
    {
      if (mask & *fp2)
	src_count++;

      mask <<= 1;
      if (mask == 0)
	{
	  mask = 1;
	  fp2++;
	}
    }
}


void
count_rr_conflicts (int state)
{
  register int i;
  register int j;
  register int count;
  register unsigned mask;
  register unsigned *baseword;
  register unsigned *wordp;
  register int m;
  register int n;

  rrc_count = 0;

  m = lookaheads[state];
  n = lookaheads[state + 1];

  if (n - m < 2) return;

  mask = 1;
  baseword = LA + m * tokensetsize;
  for (i = 0; i < ntokens; i++)
    {
      wordp = baseword;

      count = 0;
      for (j = m; j < n; j++)
	{
	  if (mask & *wordp)
	    count++;

	  wordp += tokensetsize;
	}

      if (count >= 2) rrc_count++;

      mask <<= 1;
      if (mask == 0)
	{
	  mask = 1;
	  baseword++;
	}
    }
}


void
print_reductions (int state)
{
  register int i;
  register int j;
  register int k;
  register unsigned *fp1;
  register unsigned *fp2;
  register unsigned *fp3;
  register unsigned *fp4;
  register int rule;
  register int symbol;
  register unsigned mask;
  register int m;
  register int n;
  register int default_LA;
  register int default_rule = 0;
  register int cmax;
  register int count;
  register shifts *shiftp;
  register errs *errp;
  int nodefault = 0;

  for (i = 0; i < tokensetsize; i++)
    shiftset[i] = 0;

  shiftp = shift_table[state];
  if (shiftp)
    {
      k = shiftp->nshifts;
      for (i = 0; i < k; i++)
	{
	  if (! shiftp->shifts[i]) continue;
	  symbol = accessing_symbol[shiftp->shifts[i]];
	  if (ISVAR(symbol)) break;
	  /* if this state has a shift for the error token,
	     don't use a default rule.  */
	  if (symbol == error_token_number) nodefault = 1;
	  SETBIT(shiftset, symbol);
	}
    }

  errp = err_table[state];
  if (errp)
    {
      k = errp->nerrs;
      for (i = 0; i < k; i++)
	{
	  if (! errp->errs[i]) continue;
	  symbol = errp->errs[i];
	  SETBIT(shiftset, symbol);
	}
    }

  m = lookaheads[state];
  n = lookaheads[state + 1];

  if (n - m == 1 && ! nodefault)
    {
      default_rule = LAruleno[m];

      fp1 = LA + m * tokensetsize;
      fp2 = shiftset;
      fp3 = lookaheadset;
      fp4 = lookaheadset + tokensetsize;

      while (fp3 < fp4)
	*fp3++ = *fp1++ & *fp2++;

      mask = 1;
      fp3 = lookaheadset;

      for (i = 0; i < ntokens; i++)
	{
	  if (mask & *fp3)
	    fprintf(foutput, _("    %-4s\t[reduce using rule %d (%s)]\n"),
		    tags[i], default_rule, tags[rlhs[default_rule]]);

	  mask <<= 1;
	  if (mask == 0)
	    {
	      mask = 1;
	      fp3++;
	    }
	}

      fprintf(foutput, _("    $default\treduce using rule %d (%s)\n\n"),
	      default_rule, tags[rlhs[default_rule]]);
    }
  else if (n - m >= 1)
    {
      cmax = 0;
      default_LA = -1;
      fp4 = lookaheadset + tokensetsize;

      if (! nodefault)
	for (i = m; i < n; i++)
	  {
	    fp1 = LA + i * tokensetsize;
	    fp2 = shiftset;
	    fp3 = lookaheadset;
  
	    while (fp3 < fp4)
	      *fp3++ = *fp1++ & (~(*fp2++));
  
	    count = 0;
	    mask = 1;
	    fp3 = lookaheadset;
	    for (j = 0; j < ntokens; j++)
	      {
		if (mask & *fp3)
		  count++;
  
		mask <<= 1;
		if (mask == 0)
		  {
		    mask = 1;
		    fp3++;
		  }
	      }
  
	    if (count > cmax)
	      {
		cmax = count;
		default_LA = i;
		default_rule = LAruleno[i];
	      }
  
	    fp2 = shiftset;
	    fp3 = lookaheadset;
  
	    while (fp3 < fp4)
	      *fp2++ |= *fp3++;
	  }

      for (i = 0; i < tokensetsize; i++)
        shiftset[i] = 0;

      if (shiftp)
        {
          k = shiftp->nshifts;
          for (i = 0; i < k; i++)
	    {
	      if (! shiftp->shifts[i]) continue;
	      symbol = accessing_symbol[shiftp->shifts[i]];
	      if (ISVAR(symbol)) break;
	      SETBIT(shiftset, symbol);
	    }
        }

      mask = 1;
      fp1 = LA + m * tokensetsize;
      fp2 = shiftset;
      for (i = 0; i < ntokens; i++)
	{
	  int defaulted = 0;

	  if (mask & *fp2)
	    count = 1;
	  else
	    count = 0;

	  fp3 = fp1;
	  for (j = m; j < n; j++)
	    {
	      if (mask & *fp3)
		{
		  if (count == 0)
		    {
		      if (j != default_LA)
			{
			  rule = LAruleno[j];
			  fprintf(foutput, _("    %-4s\treduce using rule %d (%s)\n"),
				  tags[i], rule, tags[rlhs[rule]]);
			}
		      else defaulted = 1;

		      count++;
		    }
		  else
		    {
		      if (defaulted)
			{
			  rule = LAruleno[default_LA];
			  fprintf(foutput, _("    %-4s\treduce using rule %d (%s)\n"),
				  tags[i], rule, tags[rlhs[rule]]);
			  defaulted = 0;
			}
		      rule = LAruleno[j];
		      fprintf(foutput, _("    %-4s\t[reduce using rule %d (%s)]\n"),
			      tags[i], rule, tags[rlhs[rule]]);
		    }
		}

	      fp3 += tokensetsize;
	    }

	  mask <<= 1;
	  if (mask == 0)
	    {
	      mask = 1;
	      /* We tried incrementing just fp1, and just fp2; both seem wrong.
		 It seems necessary to increment both in sync.  */
	      fp1++;
	      fp2++;
	    }
	}

      if (default_LA >= 0)
	{
	  fprintf(foutput, _("    $default\treduce using rule %d (%s)\n"),
		  default_rule, tags[rlhs[default_rule]]);
	}

      putc('\n', foutput);
    }
}


void
finalize_conflicts (void)
{
  FREE(conflicts);
  FREE(shiftset);
  FREE(lookaheadset);
}