2.9BSD - /usr/src/ucb/eyacc/ey4.c

   1: /* (c) 1979 Regents of the University of California */
   2: # include "ey.h"
   3: 
   4: output(){ /* print the output for the states */
   5: 
   6:   int i, j, k, c;
   7: 
   8:   settab();
   9:   arrset("yyact");
  10: 
  11:   for( i=0; i<nstate; ++i ){ /* output the stuff for state i */
  12:     nolook = (tystate[i]==0);
  13:     closure(i);
  14:     /* output actions */
  15:     aryfil( temp1, nterms+1, 0 );
  16:     for( j=0; j<cwset; ++j ){ /* look at the items */
  17:       c = *( wsets[j].pitem );
  18:       if( c>0 && c<NTBASE && temp1[c]==0 ) temp1[c] = go2(i,c);
  19:       }
  20: 
  21:     if( i == 1 ) temp1[1] = ACCEPTCODE;
  22: 
  23:     /* now, we have the shifts; look at the reductions */
  24: 
  25:     lastred = 0;
  26:     for( j=0; j<cwset; ++j ){
  27:       c = *( wsets[j].pitem );
  28:       if( c<=0 ){ /* reduction */
  29:         lastred = -c;
  30:         for( k=1; k<=nterms; ++k ){
  31:           if( ((wsets[j].ws[k>>4])&(1<<(k&017))) != 0 ) {
  32:             if( temp1[k] == 0 ) temp1[k] = c;
  33:             else if( temp1[k]<0 ){ /* reduce/reduce conflict */
  34:               settty();
  35:               fprintf( cout , "\n%d: reduce/reduce conflict (red'ns %d and %d ) on %s",
  36:                 i, -temp1[k], lastred, symnam(k) );
  37:               if( -temp1[k] > lastred ) temp1[k] = -lastred;
  38:               ++zzrrconf;
  39:               settab();
  40:               }
  41:             else { /* potential shift/reduce conflict */
  42:               switch( precftn( lastred, k ) ) {
  43: 
  44:             case 0: /* precedence does not apply */
  45: 
  46:                 settty();
  47:                 fprintf( cout , "\n%d: shift/reduce conflict (shift %d, red'n %d) on %s", i,
  48:             temp1[k], lastred, symnam(k) );
  49:                 ++zzsrconf;
  50:                 settab();
  51:                 break;
  52: 
  53:             case 1: /*  reduce */
  54: 
  55:                 temp1[k] = -lastred;
  56:                 break;
  57: 
  58:             case 2: /* error, binary operator */
  59: 
  60:                 temp1[k] = ERRCODE;
  61:                 break;
  62: 
  63:             case 3: /* shift ... leave the entry alone */
  64: 
  65:                 break;
  66:                 }
  67:               }
  68:             }
  69:           }
  70:         }
  71:       }
  72:     wract(i);
  73:     }
  74: 
  75:   settab();
  76:   arrdone();
  77: 
  78:   /* now, output the pointers to the action array */
  79:   /* also output the info about reductions */
  80:   prred();
  81:   }
  82: 
  83: prred(){ /* print the information about the actions and the reductions */
  84:   int index, i;
  85: 
  86:   arrset("yypact");
  87:   index = 1;    /* position in the output table */
  88: 
  89:   for( i=0; i<nstate; ++i ){
  90:     if( tystate[i]>0 ){  /* the state is real */
  91:       temp1[i] = index;
  92:       arrval( index );
  93:       index += tystate[i];
  94:       }
  95:     else {
  96:       arrval( temp1[-tystate[i]] );
  97:       }
  98:     }
  99: 
 100:   arrdone();
 101: 
 102:   arrset("yyr1");
 103:   for( i=1; i<nprod; ++i ) arrval( *prdptr[i] - NTBASE );
 104:   arrdone();
 105: 
 106:   arrset("yyr2");
 107:   for( i=1; i<nprod; ++i ) arrval( ( prdptr[i+1]-prdptr[i]-2 ) );
 108:   arrdone();
 109: 
 110:   }
 111: 
 112: go2(i,c){ /* do a goto on the closure state, not worrying about lookaheads */
 113:   if( c<NTBASE ) return( amem[ apstate[i]+c ] );
 114:   else return( amem[ apstate[i] + c - NTBASE + nterms ] );
 115:   }
 116: 
 117: int pkdebug = 0;
 118: apack(p, n ) int *p;{ /* pack state i from temp1 into amem */
 119:   _REGISTER k, l, off;
 120:   int j;
 121: 
 122:   /* find the spot */
 123: 
 124:   j = n;
 125:   for( off = 0; off <= j && p[off] == 0; ++off ) ;
 126:   if( off > j ){ /* no actions */
 127:     return(0);
 128:     }
 129:   j -= off;
 130:   for( k=0; k<actsiz; ++k ){
 131:     for( l=0; l<=j; ++l ){
 132:       if( p[off+l] != 0 ){
 133:         if( p[off+l] != amem[k+l] && amem[k+l] != 0 ) goto nextk;
 134:         }
 135:       }
 136:     if( pkdebug ){ settty(); fprintf( cout , "off = %d, k = %d\n", off, k ); }
 137:     /* we have found an acceptable k */
 138:     for( l=0; l<=j; ++l ){
 139:       if( p[off+l] ){
 140:         if( k+l >= actsiz ) error("action table overflow");
 141:         if( k+l >= memact ) memact = k+l;
 142:         amem[k+l] = p[off+l];
 143:         }
 144:       }
 145:     if( pkdebug ){
 146:       for( k=0; k<memact; k+=10){
 147:         fprintf( cout , "\t");
 148:         for( l=0; l<=9; ++l ) fprintf( cout , "%d ", amem[k+l] );
 149:         fprintf( cout , "\n");
 150:         }
 151:       }
 152:     return(k-off);
 153: 
 154:     nextk: ;
 155:     }
 156:   error("no space in action table");
 157:   }
 158: 
 159: go2out(){ /* output the gotos for the nontermninals */
 160:   int i, j, k, best, offset, count, cbest, times;
 161: 
 162:   settab();
 163:   arrset("yygo");
 164:   offset = 1;
 165: 
 166:   for( i=1; i<=nnonter; ++i ) {
 167:     go2gen(i);
 168: 
 169:     /* find the best one to make default */
 170: 
 171:     temp2[i] = offset;
 172: 
 173:     best = -1;
 174:     times = 0;
 175: 
 176:     for( j=0; j<=nstate; ++j ){ /* is j the most frequent */
 177:       if( tystate[j] == 0 ) continue;
 178:       if( tystate[j] == best ) continue;
 179: 
 180:       /* is tystate[j] the most frequent */
 181: 
 182:       count = 0;
 183:       cbest = tystate[j];
 184: 
 185:       for( k=j; k<=nstate; ++k ) if( tystate[k]==cbest ) ++count;
 186: 
 187:       if( count > times ){
 188:         best = cbest;
 189:         times = count;
 190:         }
 191:       }
 192: 
 193:     /* best is now the default entry */
 194: 
 195:     zzgobest += (times-1)*2;
 196:     settab();
 197:     for( j=0; j<=nstate; ++j ){
 198:       if( tystate[j] != 0 && tystate[j]!=best ){
 199:         arrval( j );
 200:         arrval( tystate[j] );
 201:         offset += 2;
 202:         zzgoent += 2;
 203:         }
 204:       }
 205: 
 206:     /* now, the default */
 207: 
 208:     zzgoent += 2;
 209:     arrval( -1 );
 210:     arrval( best );
 211:     offset += 2;
 212: 
 213:     }
 214: 
 215:   arrdone();
 216: 
 217:   arrset("yypgo");
 218:   for( i=1; i<=nnonter; ++i ) arrval( temp2[i] );
 219:   arrdone();
 220: 
 221:   }
 222: 
 223: int g2debug = 0;
 224: go2gen(c){ /* output the gotos for nonterminal c */
 225: 
 226:   int i, work, cc;
 227:   struct item *p, *q;
 228: 
 229:   /* first, find nonterminals with gotos on c */
 230: 
 231:   aryfil( temp1, nnonter+1, 0 );
 232:   temp1[c] = 1;
 233: 
 234:   work = 1;
 235:   while( work ){
 236:     work = 0;
 237:     for( i=0; i<nprod; ++i ){
 238:       if( (cc=prdptr[i][1]-NTBASE) >= 0 ){ /* cc is a nonterminal */
 239:         if( temp1[cc] != 0 ){ /* cc has a goto on c */
 240:           cc = *prdptr[i]-NTBASE; /* thus, the left side of production i does too */
 241:           if( temp1[cc] == 0 ){
 242:             work = 1;
 243:             temp1[cc] = 1;
 244:             }
 245:           }
 246:         }
 247:       }
 248:     }
 249: 
 250:   /* now, we have temp1[c] = 1 if a goto on c in closure of cc */
 251: 
 252:   if( g2debug ){
 253:     settty();
 254:     fprintf( cout , "%s: gotos on ", nontrst[c].name );
 255:     for( i=0; i<=nnonter; ++i ) if( temp1[i]) fprintf( cout , "%s ", nontrst[i].name);
 256:     fprintf( cout , "\n");
 257:     }
 258: 
 259:   /* now, go through and put gotos into tystate */
 260: 
 261:   aryfil( tystate, nstate, 0 );
 262:   settty();
 263:   fprintf( cout , "\nnonterminal %s\n", nontrst[c].name );
 264:   for( i=0; i<nstate; ++i ){
 265:     q = pstate[i+1];
 266:     for( p=pstate[i]; p<q; ++p ){
 267:       if( (cc= *p->pitem) >= NTBASE ){
 268:         if( temp1[cc -= NTBASE] ){ /* goto on c is possible */
 269:           tystate[i] = amem[indgo[i]+c];
 270:           break;
 271:           }
 272:         }
 273:       }
 274:     if( tystate[i] ) fprintf( cout , "\t%d\t%d\n", i, tystate[i]);
 275:     }
 276:   }
 277: 
 278: precftn(r,t){ /* decide a shift/reduce conflict by precedence.
 279: 			Returns 0 if action is 'do nothing',1 if action is reduce,
 280: 			2 if the action is 'error,binary operator'
 281: 			and 3 if the action is 'reduce'. */
 282: 
 283:     int lp,lt;
 284:     lp = levprd[r];
 285:     lt = trmlev[t];
 286:     if ((lt==0)||((lp&03)==0))return(0);
 287:     if((lt>>3) == (lp>>3)){
 288:         return(lt&03);
 289:         }
 290:     if((lt>>3) > (lp>>3)) return(3);
 291:     return(1);
 292:     }
 293: 
 294: int cdebug = 0; /* debug for common states */
 295: wract(i){ /* output state i */
 296:   /* temp1 has the actions, lastred the default */
 297:   int p, p0, p1, size;
 298:   int ntimes, tred, count, j;
 299:   struct item *q0, *q1;
 300: 
 301:   /* find the best choice for lastred */
 302: 
 303:   lastred = 0;
 304:   ntimes = 0;
 305:   /***** UCB MOD - full state spec if shift on error *****/
 306:   if (temp1[2] <= 0)
 307:   for( j=1; j<=nterms; ++j ){
 308:     if( temp1[j] >= 0 ) continue;
 309:     if( temp1[j]+lastred == 0 ) continue;
 310:     /* count the number of appearances of temp1[j] */
 311:     count = 0;
 312:     tred = -temp1[j];
 313:     for( p=1; p<=nterms; ++p ){
 314:       if( temp1[p]+tred == 0 ) ++count;
 315:       }
 316:     if( count >ntimes ){
 317:       lastred = tred;
 318:       ntimes = count;
 319:       }
 320:     }
 321: 
 322:     /* clear out entries in temp1 which equal lastred */
 323:     for( p=1; p<= nterms; ++p ) if( temp1[p]+lastred == 0 )temp1[p]=0;
 324: 
 325:     /* write out the state */
 326: 
 327:     /* first, check for equality with another state */
 328:     /* see if there is a nonterminal with all dots before it. */
 329: 
 330:     p0 = 0;
 331:     q1 = pstate[i+1];
 332:     for( q0=pstate[i]; q0<q1; ++q0 ){
 333:       if( (p1= *(q0->pitem) ) < NTBASE ) goto standard;
 334:       if( p0 == 0 ) p0 = p1;
 335:       else if( p0 != p1 ) goto standard;
 336:       }
 337: 
 338:     /* now, all items have dots before p0 */
 339:     if( cdebug ){
 340:       settty();
 341:       fprintf( cout , "state %d, pre-nonterminal %s\n",i,nontrst[p0-NTBASE].name);
 342:       }
 343: 
 344:     for( j=0; j<i; ++j ){
 345:       if( apstate[i] != apstate[j] ) continue;
 346: 
 347:       /* equal positions -- check items */
 348: 
 349:       if( cdebug )fprintf( cout , "states %d and %d have equal positions\n",i,j);
 350:       q1 = pstate[j+1];
 351:       for( q0=pstate[j]; q0<q1; ++q0 ){
 352:         if( *(q0->pitem) != p0 ) goto nextj;
 353:         }
 354: 
 355:       /* we have a match with state j ! */
 356: 
 357:       tystate[i] = -j;
 358:       zzacsave += tystate[j];
 359:       zznsave++;
 360:       wrstate(i);
 361:       return;
 362: 
 363:     nextj:  ;
 364:       }
 365: 
 366: 
 367:   standard:
 368:     tystate[i] = 2;
 369:     wrstate(i);
 370: 
 371:     size = 0;
 372:     for( p0=1; p0<=nterms; ++p0 )
 373:       if( (p1=temp1[p0])!=0 ) {
 374:     /***** UCB MOD - test actions are negative of symbol to be tested
 375: 			 this speeds up the parser as it is easy to check for
 376: 	 *****/
 377:         arrval( -trmset[p0].value );
 378:         if( p1 < 0 ) arrval( REDUCACT - p1 );
 379:         else if( p1 == ACCEPTCODE ) arrval( ACCEPTACT );
 380:         else if( p1 == ERRCODE ) arrval( ERRACT );
 381:         else arrval( SHIFTACT + p1 );
 382:         size += 2;
 383:         }
 384:     if( lastred ) arrval( REDUCACT + lastred );
 385:     else arrval( ERRACT );
 386:     tystate[i] = size+1; /* store entry size in tystate */
 387:     zzacent += (size+1);
 388:     return;
 389:   }
 390: 
 391: wrstate(i){ /* writes state i */
 392:     int j0,j1,s;
 393:         struct item *pp, *qq;
 394:     settty();
 395:     fprintf( cout , "\nstate %d\n",i);
 396:     qq = pstate[i+1];
 397:     for( pp=pstate[i]; pp<qq; ++pp) fprintf( cout , "\t%s\n", writem(pp));
 398: 
 399:         /* check for state equal to another */
 400: 
 401:         if( tystate[i] <= 0 ){
 402:           fprintf( cout , "\n\tsame as %d\n\n", -tystate[i] );
 403:           return;
 404:           }
 405: 
 406:     for( j0=1; j0<=nterms; ++j0 ) if( (j1=temp1[j0]) != 0 ){
 407:     fprintf( cout , "\n\t%s  ", symnam(j0) );
 408:              if( j1>0 ){ /* shift, error, or accept */
 409:                if( j1 == ACCEPTCODE ) fprintf( cout ,  "accept" );
 410:                else if( j1 == ERRCODE ) fprintf( cout ,  "error" );
 411:                else fprintf( cout ,  "shift %d", j1 );
 412:                }
 413:            else fprintf( cout , "reduce %d",-j1 );
 414:        }
 415: 
 416:     /* output the final production */
 417: 
 418:     if( lastred ) fprintf( cout , "\n\t.  reduce %d\n\n", lastred );
 419:     else fprintf( cout , "\n\t.  error\n\n" );
 420: 
 421: ret:
 422:     settab();
 423:     }

Defined functions

Defined variables