output.c

生成C++词法/语法分析的GNU语法分析器

	  else if (*p < 040 || *p >= 0177)
	    {
	      fprintf(ftable, "\\%03o", *p);
	      j += 4;
	    }
	  else
	    {
	      putc(*p, ftable);
	      j++;
	    }
	}

      putc ('\"', ftable);
      j++;
    }

  fprintf(ftable, "\n};\n#endif\n\nstatic const short yyr1[] = {     0");

  j = 10;
  for (i = 1; i <= nrules; i++)
    {
      putc(',', ftable);

      if (j >= 10)
	{
	  putc('\n', ftable);
	  j = 1;
	}
      else
	{
	  j++;
	}

      fprintf(ftable, "%6d", rlhs[i]);
    }

  FREE(rlhs + 1);

  fprintf(ftable, "\n};\n\nstatic const short yyr2[] = {     0");

  j = 10;
  for (i = 1; i < nrules; i++)
    {
      putc(',', ftable);

      if (j >= 10)
	{
	  putc('\n', ftable);
	  j = 1;
	}
      else
	{
	  j++;
	}

      fprintf(ftable, "%6d", rrhs[i + 1] - rrhs[i] - 1);
    }

  putc(',', ftable);
  if (j >= 10)
    putc('\n', ftable);

  fprintf(ftable, "%6d\n};\n", nitems - rrhs[nrules] - 1);
  FREE(rrhs + 1);
}


void
output_defines()
{
  fprintf(ftable, "\n\n#define\tYYFINAL\t\t%d\n", final_state);
  fprintf(ftable, "#define\tYYFLAG\t\t%d\n", MINSHORT);
  fprintf(ftable, "#define\tYYNTBASE\t%d\n", ntokens);
}



/* compute and output yydefact, yydefgoto, yypact, yypgoto, yytable and yycheck.  */

void
output_actions()
{
  nvectors = nstates + nvars;

  froms = NEW2(nvectors, short *);
  tos = NEW2(nvectors, short *);
  tally = NEW2(nvectors, short);
  width = NEW2(nvectors, short);

  token_actions();
  free_shifts();
  free_reductions();
  FREE(lookaheads);
  FREE(LA);
  FREE(LAruleno);
  FREE(accessing_symbol);

  goto_actions();
  FREE(goto_map + ntokens);
  FREE(from_state);
  FREE(to_state);

  sort_actions();
  pack_table();
  output_base();
  output_table();
  output_check();
}



/* figure out the actions for the specified state, indexed by lookahead token type.

   The yydefact table is output now.  The detailed info
   is saved for putting into yytable later.  */

void
token_actions()
{
  register int i;
  register int j;
  register int k;

  actrow = NEW2(ntokens, short);

  k = action_row(0);
  fprintf(ftable, "\nstatic const short yydefact[] = {%6d", k);
  save_row(0);

  j = 10;
  for (i = 1; i < nstates; i++)
    {
      putc(',', ftable);

      if (j >= 10)
	{
	  putc('\n', ftable);
	  j = 1;
	}
      else
	{
	  j++;
	}

      k = action_row(i);
      fprintf(ftable, "%6d", k);
      save_row(i);
    }

  fprintf(ftable, "\n};\n");
  FREE(actrow);
}



/* Decide what to do for each type of token if seen as the lookahead token in specified state.
   The value returned is used as the default action (yydefact) for the state.
   In addition, actrow is filled with what to do for each kind of token,
   index by symbol number, with zero meaning do the default action.
   The value MINSHORT, a very negative number, means this situation
   is an error.  The parser recognizes this value specially.

   This is where conflicts are resolved.  The loop over lookahead rules
   considered lower-numbered rules last, and the last rule considered that likes
   a token gets to handle it.  */

int
action_row(state)
int state;
{
  register int i;
  register int j;
  register int k;
  register int m;
  register int n;
  register int count;
  register int default_rule;
  register int nreds;
  register int max;
  register int rule;
  register int shift_state;
  register int symbol;
  register unsigned mask;
  register unsigned *wordp;
  register reductions *redp;
  register shifts *shiftp;
  register errs *errp;
  int nodefault = 0;  /* set nonzero to inhibit having any default reduction */

  for (i = 0; i < ntokens; i++)
    actrow[i] = 0;

  default_rule = 0;
  nreds = 0;
  redp = reduction_table[state];

  if (redp)
    {
      nreds = redp->nreds;

      if (nreds >= 1)
	{
	  /* loop over all the rules available here which require lookahead */
	  m = lookaheads[state];
	  n = lookaheads[state + 1];

	  for (i = n - 1; i >= m; i--)
	    {
	      rule = - LAruleno[i];
	      wordp = LA + i * tokensetsize;
	      mask = 1;

	      /* and find each token which the rule finds acceptable to come next */
	      for (j = 0; j < ntokens; j++)
		{
		  /* and record this rule as the rule to use if that token follows.  */
		  if (mask & *wordp)
		    actrow[j] = rule;

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

  shiftp = shift_table[state];

  /* now see which tokens are allowed for shifts in this state.
     For them, record the shift as the thing to do.  So shift is preferred to reduce.  */

  if (shiftp)
    {
      k = shiftp->nshifts;

      for (i = 0; i < k; i++)
	{
	  shift_state = shiftp->shifts[i];
	  if (! shift_state) continue;

	  symbol = accessing_symbol[shift_state];

	  if (ISVAR(symbol))
	    break;

	  actrow[symbol] = shift_state;

	  /* do not use any default reduction if there is a shift for error */

	  if (symbol == error_token_number) nodefault = 1;
	}
    }

  errp = err_table[state];

  /* See which tokens are an explicit error in this state
     (due to %nonassoc).  For them, record MINSHORT as the action.  */

  if (errp)
    {
      k = errp->nerrs;

      for (i = 0; i < k; i++)
	{
	  symbol = errp->errs[i];
	  actrow[symbol] = MINSHORT;
	}
    }

  /* now find the most common reduction and make it the default action for this state.  */

  if (nreds >= 1 && ! nodefault)
    {
      if (consistent[state])
	default_rule = redp->rules[0];
      else
	{
	  max = 0;
	  for (i = m; i < n; i++)
	    {
	      count = 0;
	      rule = - LAruleno[i];
    
	      for (j = 0; j < ntokens; j++)
		{
		  if (actrow[j] == rule)
		    count++;
		}
    
	      if (count > max)
		{
		  max = count;
		  default_rule = rule;
		}
	    }
    
	  /* actions which match the default are replaced with zero,
	     which means "use the default" */
    
	  if (max > 0)
	    {
	      for (j = 0; j < ntokens; j++)
		{
		  if (actrow[j] == default_rule)
		    actrow[j] = 0;
		}
    
	      default_rule = - default_rule;
	    }
	}
    }

  /* If have no default rule, the default is an error.
     So replace any action which says "error" with "use default".  */

  if (default_rule == 0)
    for (j = 0; j < ntokens; j++)
      {
	if (actrow[j] == MINSHORT)
	  actrow[j] = 0;
      }

  return (default_rule);
}


void
save_row(state)
int state;
{
  register int i;
  register int count;
  register short *sp;
  register short *sp1;
  register short *sp2;

  count = 0;
  for (i = 0; i < ntokens; i++)
    {
      if (actrow[i] != 0)
	count++;
    }

  if (count == 0)
    return;

  froms[state] = sp1 = sp = NEW2(count, short);
  tos[state] = sp2 = NEW2(count, short);

  for (i = 0; i < ntokens; i++)
    {
      if (actrow[i] != 0)
	{
	  *sp1++ = i;
	  *sp2++ = actrow[i];
	}
    }

  tally[state] = count;
  width[state] = sp1[-1] - sp[0] + 1;
}



/* figure out what to do after reducing with each rule,
   depending on the saved state from before the beginning
   of parsing the data that matched this rule.

   The yydefgoto table is output now.  The detailed info
   is saved for putting into yytable later.  */

void
goto_actions()
{
  register int i;
  register int j;
  register int k;

  state_count = NEW2(nstates, short);

  k = default_goto(ntokens);
  fprintf(ftable, "\nstatic const short yydefgoto[] = {%6d", k);
  save_column(ntokens, k);

  j = 10;
  for (i = ntokens + 1; i < nsyms; i++)
    {
      putc(',', ftable);

      if (j >= 10)
	{
	  putc('\n', ftable);
	  j = 1;
	}
      else
	{
	  j++;
	}

      k = default_goto(i);
      fprintf(ftable, "%6d", k);
      save_column(i, k);
    }

  fprintf(ftable, "\n};\n");
  FREE(state_count);
}



int
default_goto(symbol)
int symbol;
{
  register int i;
  register int m;
  register int n;
  register int default_state;
  register int max;

  m = goto_map[symbol];
  n = goto_map[symbol + 1];

  if (m == n)
    return (-1);

  for (i = 0; i < nstates; i++)
    state_count[i] = 0;

  for (i = m; i < n; i++)
    state_count[to_state[i]]++;

  max = 0;
  default_state = -1;

  for (i = 0; i < nstates; i++)
    {
      if (state_count[i] > max)
	{
	  max = state_count[i];
	  default_state = i;
	}
    }

  return (default_state);
}


void
save_column(symbol, default_state)
int symbol;
int default_state;
{
  register int i;
  register int m;
  register int n;
  register short *sp;
  register short *sp1;
  register short *sp2;
  register int count;
  register int symno;

  m = goto_map[symbol];
  n = goto_map[symbol + 1];

  count = 0;
  for (i = m; i < n; i++)
    {
      if (to_state[i] != default_state)
	count++;
    }

  if (count == 0)
    return;

  symno = symbol - ntokens + nstates;

  froms[symno] = sp1 = sp = NEW2(count, short);
  tos[symno] = sp2 = NEW2(count, short);

  for (i = m; i < n; i++)
    {
      if (to_state[i] != default_state)
	{
	  *sp1++ = from_state[i];
	  *sp2++ = to_state[i];
	}
    }

  tally[symno] = count;
  width[symno] = sp1[-1] - sp[0] + 1;
}



/* the next few functions decide how to pack 
   the actions and gotos information into yytable. */

void
sort_actions()
{
  register int i;
  register int j;
  register int k;
  register int t;
  register int w;

  order = NEW2(nvectors, short);
  nentries = 0;

  for (i = 0; i < nvectors; i++)
    {
      if (tally[i] > 0)
	{
	  t = tally[i];
	  w = width[i];
	  j = nentries - 1;

	  while (j >= 0 && (width[order[j]] < w))
	    j--;

	  while (j >= 0 && (width[order[j]] == w) && (tally[order[j]] < t))
	    j--;

	  for (k = nentries - 1; k > j; k--)
	    order[k + 1] = order[k];

	  order[j + 1] = i;
	  nentries++;
	}
    }
}


void
pack_table()
{
  register int i;
  register int place;
  register int state;

  base = NEW2(nvectors, short);
  pos = NEW2(nentries, short);
  table = NEW2(MAXTABLE, short);
  check = NEW2(MAXTABLE, short);

  lowzero = 0;
  high = 0;