2.9BSD - /usr/src/cmd/yacc/y3.c

   1: # include "dextern"
   2: 
   3:     /* important local variables */
   4: int lastred;  /* the number of the last reduction of a state */
   5: int defact[NSTATES];  /* the default actions of states */
   6: 
   7: output(){ /* print the output for the states */
   8: 
   9:     int i, k, c;
  10:     register struct wset *u, *v;
  11: 
  12:     fprintf( ftable, "short yyexca[] ={\n" );
  13: 
  14:     SLOOP(i) { /* output the stuff for state i */
  15:         nolook = !(tystate[i]==MUSTLOOKAHEAD);
  16:         closure(i);
  17:         /* output actions */
  18:         nolook = 1;
  19:         aryfil( temp1, ntokens+nnonter+1, 0 );
  20:         WSLOOP(wsets,u){
  21:             c = *( u->pitem );
  22:             if( c>1 && c<NTBASE && temp1[c]==0 ) {
  23:                 WSLOOP(u,v){
  24:                     if( c == *(v->pitem) ) putitem( v->pitem+1, (struct looksets *)0 );
  25:                     }
  26:                 temp1[c] = state(c);
  27:                 }
  28:             else if( c > NTBASE && temp1[ (c -= NTBASE) + ntokens ] == 0 ){
  29:                 temp1[ c+ntokens ] = amem[indgo[i]+c];
  30:                 }
  31:             }
  32: 
  33:         if( i == 1 ) temp1[1] = ACCEPTCODE;
  34: 
  35:         /* now, we have the shifts; look at the reductions */
  36: 
  37:         lastred = 0;
  38:         WSLOOP(wsets,u){
  39:             c = *( u->pitem );
  40:             if( c<=0 ){ /* reduction */
  41:                 lastred = -c;
  42:                 TLOOP(k){
  43:                     if( BIT(u->ws.lset,k) ){
  44:                           if( temp1[k] == 0 ) temp1[k] = c;
  45:                           else if( temp1[k]<0 ){ /* reduce/reduce conflict */
  46:                             if( foutput!=NULL )
  47:                               fprintf( foutput,
  48:                                 "\n%d: reduce/reduce conflict (red'ns %d and %d ) on %s",
  49:                                 i, -temp1[k], lastred, symnam(k) );
  50:                             if( -temp1[k] > lastred ) temp1[k] = -lastred;
  51:                             ++zzrrconf;
  52:                             }
  53:                           else { /* potential shift/reduce conflict */
  54:                             precftn( lastred, k, i );
  55:                             }
  56:                         }
  57:                     }
  58:                 }
  59:             }
  60:         wract(i);
  61:         }
  62: 
  63:     fprintf( ftable, "\t};\n" );
  64: 
  65:     wdef( "YYNPROD", nprod );
  66: 
  67:     }
  68: 
  69: int pkdebug = 0;
  70: apack(p, n ) int *p;{ /* pack state i from temp1 into amem */
  71:     int off;
  72:     register *pp, *qq, *rr;
  73:     int *q, *r;
  74: 
  75:     /* we don't need to worry about checking because we
  76: 	   we will only look entries known to be there... */
  77: 
  78:     /* eliminate leading and trailing 0's */
  79: 
  80:     q = p+n;
  81:     for( pp=p,off=0 ; *pp==0 && pp<=q; ++pp,--off ) /* VOID */ ;
  82:     if( pp > q ) return(0);  /* no actions */
  83:     p = pp;
  84: 
  85:     /* now, find a place for the elements from p to q, inclusive */
  86: 
  87:     r = &amem[ACTSIZE-1];
  88:     for( rr=amem; rr<=r; ++rr,++off ){  /* try rr */
  89:         for( qq=rr,pp=p ; pp<=q ; ++pp,++qq){
  90:             if( *pp != 0 ){
  91:                 if( *pp != *qq && *qq != 0 ) goto nextk;
  92:                 }
  93:             }
  94: 
  95:         /* we have found an acceptable k */
  96: 
  97:         if( pkdebug && foutput!=NULL ) fprintf( foutput, "off = %d, k = %d\n", off, rr-amem );
  98: 
  99:         for( qq=rr,pp=p; pp<=q; ++pp,++qq ){
 100:             if( *pp ){
 101:                 if( qq > r ) error( "action table overflow" );
 102:                 if( qq>memp ) memp = qq;
 103:                 *qq = *pp;
 104:                 }
 105:             }
 106:         if( pkdebug && foutput!=NULL ){
 107:             for( pp=amem; pp<= memp; pp+=10 ){
 108:                 fprintf( foutput, "\t");
 109:                 for( qq=pp; qq<=pp+9; ++qq ) fprintf( foutput, "%d ", *qq );
 110:                 fprintf( foutput, "\n");
 111:                 }
 112:             }
 113:         return( off );
 114: 
 115:         nextk: ;
 116:         }
 117:     error("no space in action table" );
 118:     /* NOTREACHED */
 119:     }
 120: 
 121: go2out(){ /* output the gotos for the nontermninals */
 122:     int i, j, k, best, count, cbest, times;
 123: 
 124:     fprintf( ftemp, "$\n" );  /* mark begining of gotos */
 125: 
 126:     for( i=1; i<=nnonter; ++i ) {
 127:         go2gen(i);
 128: 
 129:         /* find the best one to make default */
 130: 
 131:         best = -1;
 132:         times = 0;
 133: 
 134:         for( j=0; j<=nstate; ++j ){ /* is j the most frequent */
 135:             if( tystate[j] == 0 ) continue;
 136:             if( tystate[j] == best ) continue;
 137: 
 138:             /* is tystate[j] the most frequent */
 139: 
 140:             count = 0;
 141:             cbest = tystate[j];
 142: 
 143:             for( k=j; k<=nstate; ++k ) if( tystate[k]==cbest ) ++count;
 144: 
 145:             if( count > times ){
 146:                 best = cbest;
 147:                 times = count;
 148:                 }
 149:             }
 150: 
 151:         /* best is now the default entry */
 152: 
 153:         zzgobest += (times-1);
 154:         for( j=0; j<=nstate; ++j ){
 155:             if( tystate[j] != 0 && tystate[j]!=best ){
 156:                 fprintf( ftemp, "%d,%d,", j, tystate[j] );
 157:                 zzgoent += 1;
 158:                 }
 159:             }
 160: 
 161:         /* now, the default */
 162: 
 163:         zzgoent += 1;
 164:         fprintf( ftemp, "%d\n", best );
 165: 
 166:         }
 167: 
 168: 
 169: 
 170:     }
 171: 
 172: int g2debug = 0;
 173: go2gen(c){ /* output the gotos for nonterminal c */
 174: 
 175:     int i, work, cc;
 176:     struct item *p, *q;
 177: 
 178: 
 179:     /* first, find nonterminals with gotos on c */
 180: 
 181:     aryfil( temp1, nnonter+1, 0 );
 182:     temp1[c] = 1;
 183: 
 184:     work = 1;
 185:     while( work ){
 186:         work = 0;
 187:         PLOOP(0,i){
 188:             if( (cc=prdptr[i][1]-NTBASE) >= 0 ){ /* cc is a nonterminal */
 189:                 if( temp1[cc] != 0 ){ /* cc has a goto on c */
 190:                     cc = *prdptr[i]-NTBASE; /* thus, the left side of production i does too */
 191:                     if( temp1[cc] == 0 ){
 192:                           work = 1;
 193:                           temp1[cc] = 1;
 194:                           }
 195:                     }
 196:                 }
 197:             }
 198:         }
 199: 
 200:     /* now, we have temp1[c] = 1 if a goto on c in closure of cc */
 201: 
 202:     if( g2debug && foutput!=NULL ){
 203:         fprintf( foutput, "%s: gotos on ", nontrst[c].name );
 204:         NTLOOP(i) if( temp1[i] ) fprintf( foutput, "%s ", nontrst[i].name);
 205:         fprintf( foutput, "\n");
 206:         }
 207: 
 208:     /* now, go through and put gotos into tystate */
 209: 
 210:     aryfil( tystate, nstate, 0 );
 211:     SLOOP(i){
 212:         ITMLOOP(i,p,q){
 213:             if( (cc= *p->pitem) >= NTBASE ){
 214:                 if( temp1[cc -= NTBASE] ){ /* goto on c is possible */
 215:                     tystate[i] = amem[indgo[i]+c];
 216:                     break;
 217:                     }
 218:                 }
 219:             }
 220:         }
 221:     }
 222: 
 223: precftn(r,t,s){ /* decide a shift/reduce conflict by precedence.
 224: 	/* r is a rule number, t a token number */
 225:     /* the conflict is in state s */
 226:     /* temp1[t] is changed to reflect the action */
 227: 
 228:     int lp,lt, action;
 229: 
 230:     lp = levprd[r];
 231:     lt = toklev[t];
 232:     if( PLEVEL(lt) == 0 || PLEVEL(lp) == 0 ) {
 233:         /* conflict */
 234:         if( foutput != NULL ) fprintf( foutput, "\n%d: shift/reduce conflict (shift %d, red'n %d) on %s",
 235:                         s, temp1[t], r, symnam(t) );
 236:         ++zzsrconf;
 237:         return;
 238:         }
 239:     if( PLEVEL(lt) == PLEVEL(lp) ) action = ASSOC(lt);
 240:     else if( PLEVEL(lt) > PLEVEL(lp) ) action = RASC;  /* shift */
 241:     else action = LASC;  /* reduce */
 242: 
 243:     switch( action ){
 244: 
 245:     case BASC:  /* error action */
 246:         temp1[t] = ERRCODE;
 247:         return;
 248: 
 249:     case LASC:  /* reduce */
 250:         temp1[t] = -r;
 251:         return;
 252: 
 253:         }
 254:     }
 255: 
 256: wract(i){ /* output state i */
 257:     /* temp1 has the actions, lastred the default */
 258:     int p, p0, p1;
 259:     int ntimes, tred, count, j;
 260:     int flag;
 261: 
 262:     /* find the best choice for lastred */
 263: 
 264:     lastred = 0;
 265:     ntimes = 0;
 266:     TLOOP(j){
 267:         if( temp1[j] >= 0 ) continue;
 268:         if( temp1[j]+lastred == 0 ) continue;
 269:         /* count the number of appearances of temp1[j] */
 270:         count = 0;
 271:         tred = -temp1[j];
 272:         levprd[tred] |= REDFLAG;
 273:         TLOOP(p){
 274:             if( temp1[p]+tred == 0 ) ++count;
 275:             }
 276:         if( count >ntimes ){
 277:             lastred = tred;
 278:             ntimes = count;
 279:             }
 280:         }
 281: 
 282:     /* for error recovery, arrange that, if there is a shift on the
 283: 	/* error recovery token, `error', that the default be the error action */
 284:     if( temp1[1] > 0 ) lastred = 0;
 285: 
 286:     /* clear out entries in temp1 which equal lastred */
 287:     TLOOP(p) if( temp1[p]+lastred == 0 )temp1[p]=0;
 288: 
 289:     wrstate(i);
 290:     defact[i] = lastred;
 291: 
 292:     flag = 0;
 293:     TLOOP(p0){
 294:         if( (p1=temp1[p0])!=0 ) {
 295:             if( p1 < 0 ){
 296:                 p1 = -p1;
 297:                 goto exc;
 298:                 }
 299:             else if( p1 == ACCEPTCODE ) {
 300:                 p1 = -1;
 301:                 goto exc;
 302:                 }
 303:             else if( p1 == ERRCODE ) {
 304:                 p1 = 0;
 305:                 goto exc;
 306:             exc:
 307:                 if( flag++ == 0 ) fprintf( ftable, "-1, %d,\n", i );
 308:                 fprintf( ftable, "\t%d, %d,\n", tokset[p0].value, p1 );
 309:                 ++zzexcp;
 310:                 }
 311:             else {
 312:                 fprintf( ftemp, "%d,%d,", tokset[p0].value, p1 );
 313:                 ++zzacent;
 314:                 }
 315:             }
 316:         }
 317:     if( flag ) {
 318:         defact[i] = -2;
 319:         fprintf( ftable, "\t-2, %d,\n", lastred );
 320:         }
 321:     fprintf( ftemp, "\n" );
 322:     return;
 323:     }
 324: 
 325: wrstate(i){ /* writes state i */
 326:     register j0,j1;
 327:     register struct item *pp, *qq;
 328:     register struct wset *u;
 329: 
 330:     if( foutput == NULL ) return;
 331:     fprintf( foutput, "\nstate %d\n",i);
 332:     ITMLOOP(i,pp,qq) fprintf( foutput, "\t%s\n", writem(pp->pitem));
 333:     if( tystate[i] == MUSTLOOKAHEAD ){
 334:         /* print out empty productions in closure */
 335:         WSLOOP( wsets+(pstate[i+1]-pstate[i]), u ){
 336:             if( *(u->pitem) < 0 ) fprintf( foutput, "\t%s\n", writem(u->pitem) );
 337:             }
 338:         }
 339: 
 340:     /* check for state equal to another */
 341: 
 342:     TLOOP(j0) if( (j1=temp1[j0]) != 0 ){
 343:         fprintf( foutput, "\n\t%s  ", symnam(j0) );
 344:         if( j1>0 ){ /* shift, error, or accept */
 345:             if( j1 == ACCEPTCODE ) fprintf( foutput,  "accept" );
 346:             else if( j1 == ERRCODE ) fprintf( foutput, "error" );
 347:             else fprintf( foutput,  "shift %d", j1 );
 348:             }
 349:         else fprintf( foutput, "reduce %d",-j1 );
 350:         }
 351: 
 352:     /* output the final production */
 353: 
 354:     if( lastred ) fprintf( foutput, "\n\t.  reduce %d\n\n", lastred );
 355:     else fprintf( foutput, "\n\t.  error\n\n" );
 356: 
 357:     /* now, output nonterminal actions */
 358: 
 359:     j1 = ntokens;
 360:     for( j0 = 1; j0 <= nnonter; ++j0 ){
 361:         if( temp1[++j1] ) fprintf( foutput, "\t%s  goto %d\n", symnam( j0+NTBASE), temp1[j1] );
 362:         }
 363: 
 364:     }
 365: 
 366: wdef( s, n ) char *s; { /* output a definition of s to the value n */
 367:     fprintf( ftable, "# define %s %d\n", s, n );
 368:     }
 369: 
 370: warray( s, v, n ) char *s; int *v, n; {
 371: 
 372:     register i;
 373: 
 374:     fprintf( ftable, "short %s[]={\n", s );
 375:     for( i=0; i<n; ){
 376:         if( i%10 == 0 ) fprintf( ftable, "\n" );
 377:         fprintf( ftable, "%4d", v[i] );
 378:         if( ++i == n ) fprintf( ftable, " };\n" );
 379:         else fprintf( ftable, "," );
 380:         }
 381:     }
 382: 
 383: hideprod(){
 384:     /* in order to free up the mem and amem arrays for the optimizer,
 385: 	/* and still be able to output yyr1, etc., after the sizes of
 386: 	/* the action array is known, we hide the nonterminals
 387: 	/* derived by productions in levprd.
 388: 	*/
 389: 
 390:     register i, j;
 391: 
 392:     j = 0;
 393:     levprd[0] = 0;
 394:     PLOOP(1,i){
 395:         if( !(levprd[i] & REDFLAG) ){
 396:             ++j;
 397:             if( foutput != NULL ){
 398:                 fprintf( foutput, "Rule not reduced:   %s\n", writem( prdptr[i] ) );
 399:                 }
 400:             }
 401:         levprd[i] = *prdptr[i] - NTBASE;
 402:         }
 403:     if( j ) fprintf( stdout, "%d rules never reduced\n", j );
 404:     }

Defined functions

Defined variables