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1.1 ! root 1: # ! 2: static char sccsid[] = "@(#)c20.c 4.3 10/17/80"; ! 3: /* char C20[] = {"@(#)c20.c 1.35 80/08/26 14:13:40"}; /* sccs ident */ ! 4: /* ! 5: * C object code improver ! 6: */ ! 7: ! 8: #include "c2.h" ! 9: #include <stdio.h> ! 10: #include <ctype.h> ! 11: ! 12: char _sibuf[BUFSIZ], _sobuf[BUFSIZ]; ! 13: int ioflag; ! 14: long isn = 2000000; ! 15: struct optab *oplook(); ! 16: struct optab *getline(); ! 17: long lgensym[10] = ! 18: {100000L,200000L,300000L,400000L,500000L,600000L,700000L,800000L,900000L,1000000L}; ! 19: ! 20: struct node * ! 21: alloc(an) ! 22: { ! 23: register int n; ! 24: register char *p; ! 25: ! 26: n = an; ! 27: n+=sizeof(char *)-1; ! 28: n &= ~(sizeof(char *)-1); ! 29: if (lasta+n >= lastr) { ! 30: if (sbrk(2000) == -1) { ! 31: fprintf(stderr, "Optimizer: out of space\n"); ! 32: exit(1); ! 33: } ! 34: lastr += 2000; ! 35: } ! 36: p = lasta; ! 37: lasta += n; ! 38: return(p); ! 39: } ! 40: ! 41: main(argc, argv) ! 42: char **argv; ! 43: { ! 44: register int niter, maxiter, isend; ! 45: int nflag,infound; ! 46: ! 47: nflag = 0; infound=0; argc--; argv++; ! 48: while (argc>0) {/* get flags */ ! 49: if (**argv=='+') debug++; ! 50: else if (**argv=='-') { ! 51: if ((*argv)[1]=='i') ioflag++; else nflag++; ! 52: } else if (infound==0) { ! 53: if (freopen(*argv, "r", stdin) ==NULL) { ! 54: fprintf(stderr,"C2: can't find %s\n", *argv); ! 55: exit(1); ! 56: } ! 57: setbuf(stdin,_sibuf); ++infound; ! 58: } else if (freopen(*argv, "w", stdout) ==NULL) { ! 59: fprintf(stderr,"C2: can't create %s\n", *argv); ! 60: exit(1); ! 61: } ! 62: setbuf(stdout,_sobuf); ! 63: argc--; argv++; ! 64: } ! 65: lasta = lastr = sbrk(2); ! 66: opsetup(); ! 67: lasta = firstr = lastr = alloc(0); ! 68: maxiter = 0; ! 69: do { ! 70: isend = input(); ! 71: niter = 0; ! 72: bmove(); ! 73: do { ! 74: refcount(); ! 75: do { ! 76: iterate(); ! 77: clearreg(); ! 78: niter++; ! 79: } while (nchange); ! 80: comjump(); ! 81: rmove(); ! 82: } while (nchange || jumpsw()); ! 83: addsob(); ! 84: output(); ! 85: if (niter > maxiter) ! 86: maxiter = niter; ! 87: lasta = firstr; ! 88: } while (isend); ! 89: if (nflag) { ! 90: fprintf(stderr,"%d iterations\n", maxiter); ! 91: fprintf(stderr,"%d jumps to jumps\n", nbrbr); ! 92: fprintf(stderr,"%d inst. after jumps\n", iaftbr); ! 93: fprintf(stderr,"%d jumps to .+1\n", njp1); ! 94: fprintf(stderr,"%d redundant labels\n", nrlab); ! 95: fprintf(stderr,"%d cross-jumps\n", nxjump); ! 96: fprintf(stderr,"%d code motions\n", ncmot); ! 97: fprintf(stderr,"%d branches reversed\n", nrevbr); ! 98: fprintf(stderr,"%d redundant moves\n", redunm); ! 99: fprintf(stderr,"%d simplified addresses\n", nsaddr); ! 100: fprintf(stderr,"%d loops inverted\n", loopiv); ! 101: fprintf(stderr,"%d redundant jumps\n", nredunj); ! 102: fprintf(stderr,"%d common seqs before jmp's\n", ncomj); ! 103: fprintf(stderr,"%d skips over jumps\n", nskip); ! 104: fprintf(stderr,"%d sob's added\n", nsob); ! 105: fprintf(stderr,"%d redundant tst's\n", nrtst); ! 106: fprintf(stderr,"%d jump on bit\n", nbj); ! 107: fprintf(stderr,"%d field operations\n", nfield); ! 108: fprintf(stderr,"%dK core\n", ((unsigned)lastr+01777) >> 10); ! 109: } ! 110: putc('\n',stdout); ! 111: fflush(stdout); exit(0); ! 112: } ! 113: ! 114: input() ! 115: { ! 116: register struct node *p, *lastp; ! 117: struct optab *op; register char *cp1; ! 118: static struct optab F77JSW = {".long", T(JSW,1)}; ! 119: ! 120: lastp = &first; ! 121: for (;;) { ! 122: top: ! 123: op = getline(); ! 124: if (debug && op==0) fprintf(stderr,"? %s\n",line); ! 125: switch (op->opcode&0377) { ! 126: ! 127: case LABEL: ! 128: p = alloc(sizeof first); ! 129: if (isdigit(line[0]) && (p->labno=locdef(line)) || ! 130: (line[0] == 'L') && (p->labno=getnum(line+1))) { ! 131: p->combop = LABEL; ! 132: if (p->labno<100000L && isn<=p->labno) isn=1+p->labno; ! 133: p->code = 0; ! 134: } else { ! 135: p->combop = DLABEL; ! 136: p->labno = 0; ! 137: p->code = copy(line); ! 138: } ! 139: break; ! 140: ! 141: case LGEN: ! 142: if (*curlp!='L' && !locuse(curlp)) goto std; ! 143: op= &F77JSW; ! 144: case JBR: ! 145: if (op->opcode==T(JBR,RET) || op->opcode==T(JBR,RSB)) goto std; ! 146: case CBR: ! 147: case JMP: ! 148: case JSW: ! 149: case SOBGEQ: case SOBGTR: case AOBLEQ: case AOBLSS: case ACB: ! 150: p = alloc(sizeof first); ! 151: p->combop = op->opcode; p->code=0; cp1=curlp; ! 152: if ((!isdigit(*cp1) || 0==(p->labno=locuse(cp1))) && ! 153: (*cp1!='L' || 0==(p->labno = getnum(cp1+1)))) {/* jbs, etc.? */ ! 154: while (*cp1++); while (*--cp1!=',' && cp1!=curlp); ! 155: if (cp1==curlp || ! 156: (!isdigit(*++cp1) || 0==(p->labno=locuse(cp1))) && ! 157: (*cp1!='L' || 0==(p->labno=getnum(cp1+1)))) ! 158: p->labno = 0; ! 159: else *--cp1=0; ! 160: p->code = copy(curlp); ! 161: } ! 162: if (isn<=p->labno) isn=1+p->labno; ! 163: break; ! 164: ! 165: case MOVA: ! 166: p=alloc(sizeof first); ! 167: p->combop=op->opcode; p->code=0; cp1=curlp+1; ! 168: if (cp1[-1]=='L' || isdigit(cp1[-1])) { ! 169: while (*cp1++!=','); *--cp1=0; ! 170: if (0!=(p->labno=locuse(curlp)) || ! 171: 0!=(p->labno=getnum(curlp+1))) p->code=copy(cp1+1); ! 172: else {*cp1=','; p->code=copy(curlp);} ! 173: } else {p->code=copy(--cp1); p->labno=0;} ! 174: break; ! 175: ! 176: case SET: ! 177: case COMM: ! 178: case LCOMM: ! 179: printf("%s\n",line); goto top; ! 180: ! 181: case BSS: ! 182: case DATA: ! 183: for (;;) { ! 184: printf("%s%c",line,(op->opcode==LABEL ? ':' : '\n')); ! 185: if (op->opcode==TEXT) goto top; ! 186: if (END==(op=getline())->opcode) {/* dangling .data is bad for you */ ! 187: printf(".text\n"); ! 188: break; ! 189: } ! 190: } ! 191: ! 192: std: ! 193: default: ! 194: p = alloc(sizeof first); ! 195: p->combop = op->opcode; ! 196: p->labno = 0; ! 197: p->code = copy(curlp); ! 198: break; ! 199: ! 200: } ! 201: p->forw = 0; ! 202: p->back = lastp; ! 203: p->pop = op; ! 204: lastp->forw = p; ! 205: lastp = p; ! 206: p->ref = 0; ! 207: if (p->op==CASE) { ! 208: char *lp; int ncase; ! 209: lp=curlp; while (*lp++); while (*--lp!='$'); ncase=getnum(lp+1); ! 210: if (LABEL!=(getline())->opcode) abort(-2); ! 211: do { ! 212: if (WGEN!=(getline())->opcode) abort(-3); ! 213: p = alloc(sizeof first); p->combop = JSW; p->code = 0; ! 214: lp=curlp; while(*lp++!='-'); *--lp=0; p->labno=getnum(curlp+1); ! 215: if (isn<=p->labno) isn=1+p->labno; ! 216: p->forw = 0; p->back = lastp; lastp->forw = p; lastp = p; ! 217: p->ref = 0; p->pop=0; ! 218: } while (--ncase>=0); ! 219: } ! 220: if (op->opcode==EROU) ! 221: return(1); ! 222: if (op->opcode==END) ! 223: return(0); ! 224: } ! 225: } ! 226: ! 227: struct optab * ! 228: getline() ! 229: { ! 230: register char *lp; ! 231: register c; ! 232: static struct optab OPLABEL={"",LABEL}; ! 233: static struct optab OPEND={"",END}; ! 234: ! 235: lp = line; ! 236: while (EOF!=(c=getchar()) && isspace(c)); ! 237: while (EOF!=c) { ! 238: if (c==':') { ! 239: *lp++ = 0; ! 240: return(&OPLABEL); ! 241: } ! 242: if (c=='\n') { ! 243: *lp++ = 0; ! 244: return(oplook()); ! 245: } ! 246: *lp++ = c; ! 247: c = getchar(); ! 248: } ! 249: *lp++ = 0; ! 250: return(&OPEND); ! 251: } ! 252: ! 253: long ! 254: getnum(p) ! 255: register char *p; ! 256: { ! 257: register c; int neg; register long n; ! 258: ! 259: n = 0; neg=0; if (*p=='-') {++neg; ++p;} ! 260: while (isdigit(c = *p++)) { ! 261: c -= '0'; n *= 10; if (neg) n -= c; else n += c; ! 262: } ! 263: if (*--p != 0) ! 264: return(0); ! 265: return(n); ! 266: } ! 267: ! 268: locuse(p) ! 269: register char *p; ! 270: { ! 271: register c; int neg; register long n; ! 272: ! 273: if (!isdigit(p[0]) || p[1] != 'f' && p[1] != 'b' || p[2]) return(0); ! 274: return (lgensym[p[0] - '0'] - (p[1] == 'b')); ! 275: } ! 276: ! 277: locdef(p) ! 278: register char *p; ! 279: { ! 280: ! 281: if (!isdigit(p[0]) || p[1]) return(0); ! 282: return (lgensym[p[0] - '0']++); ! 283: } ! 284: ! 285: output() ! 286: { ! 287: register struct node *t; ! 288: int casebas; ! 289: ! 290: t = &first; ! 291: while (t = t->forw) switch (t->op) { ! 292: ! 293: case END: ! 294: fflush(stdout); ! 295: return; ! 296: ! 297: case LABEL: ! 298: printf("L%d:", t->labno); ! 299: continue; ! 300: ! 301: case DLABEL: ! 302: printf("%s:", t->code); ! 303: continue; ! 304: ! 305: case CASE: ! 306: casebas=0; ! 307: ! 308: default: std: ! 309: if (t->pop==0) {/* must find it */ ! 310: register struct optab *p; ! 311: for (p=optab; p->opstring[0]; ++p) ! 312: if (p->opcode==t->combop) {t->pop=p; break;} ! 313: } ! 314: printf("%s", t->pop->opstring); ! 315: if (t->code) printf("\t%s", t->code); ! 316: if (t->labno!=0) printf("%cL%d\n", ! 317: (t->code ? ',' : '\t'), ! 318: t->labno); ! 319: else printf("\n"); ! 320: continue; ! 321: ! 322: case MOVA: ! 323: if (t->labno==0) goto std; ! 324: printf("mova%c\tL%d,%s\n","bwlq"[t->subop-BYTE],t->labno,t->code); ! 325: continue; ! 326: ! 327: case JSW: ! 328: if (t->subop!=0) {/* F77JSW */ ! 329: printf(".long\tL%d\n",t->labno); continue; ! 330: } ! 331: if (casebas==0) printf("L%d:\n",casebas=isn++); ! 332: printf(".word L%d-L%d\n", t->labno, casebas); ! 333: continue; ! 334: ! 335: } ! 336: } ! 337: ! 338: char * ! 339: copy(ap) ! 340: char *ap; ! 341: { ! 342: register char *p, *np; ! 343: char *onp; ! 344: register n; ! 345: int na; ! 346: ! 347: na = nargs(); ! 348: p = ap; ! 349: n = 0; ! 350: if (*p==0) ! 351: return(0); ! 352: do ! 353: n++; ! 354: while (*p++); ! 355: if (na>1) { ! 356: p = (&ap)[1]; ! 357: while (*p++) ! 358: n++; ! 359: } ! 360: onp = np = alloc(n); ! 361: p = ap; ! 362: while (*np++ = *p++); ! 363: if (na>1) { ! 364: p = (&ap)[1]; ! 365: np--; ! 366: while (*np++ = *p++); ! 367: } ! 368: return(onp); ! 369: } ! 370: ! 371: #define OPHS 560 ! 372: struct optab *ophash[OPHS]; ! 373: ! 374: opsetup() ! 375: { ! 376: register struct optab *optp, **ophp; ! 377: register int i,t; ! 378: ! 379: for(i=NREG+5;--i>=0;) regs[i]=alloc(20); ! 380: for (optp = optab; optp->opstring[0]; optp++) { ! 381: t=7; i=0; while (--t>=0) i+= i+optp->opstring[t]; ! 382: ophp = &ophash[i % OPHS]; ! 383: while (*ophp++) { ! 384: /* fprintf(stderr,"\ncollision: %d %s %s", ! 385: /* ophp-1-ophash,optp->opstring,(*(ophp-1))->opstring); ! 386: */ ! 387: if (ophp > &ophash[OPHS]) ! 388: ophp = ophash; ! 389: } ! 390: *--ophp = optp; ! 391: } ! 392: } ! 393: ! 394: struct optab * ! 395: oplook() ! 396: { ! 397: register struct optab *optp,**ophp; ! 398: register char *p,*p2; ! 399: register int t; ! 400: char tempop[20]; ! 401: static struct optab OPNULL={"",0}; ! 402: ! 403: for (p=line, p2=tempop; *p && !isspace(*p); *p2++= *p++); *p2=0; p2=p; ! 404: while (isspace(*p2)) ++p2; curlp=p2; ! 405: t=0; while(--p>=line) t += t+*p; ophp = &ophash[t % OPHS]; ! 406: while (optp = *ophp) { ! 407: if (equstr(tempop,optp->opstring)) return(optp); ! 408: if ((++ophp) >= &ophash[OPHS]) ophp = ophash; ! 409: } ! 410: curlp = line; ! 411: return(&OPNULL); ! 412: } ! 413: ! 414: refcount() ! 415: { ! 416: register struct node *p, *lp; ! 417: struct node *labhash[LABHS]; ! 418: register struct node **hp; ! 419: ! 420: for (hp = labhash; hp < &labhash[LABHS];) ! 421: *hp++ = 0; ! 422: for (p = first.forw; p!=0; p = p->forw) ! 423: if (p->op==LABEL) { ! 424: labhash[p->labno % LABHS] = p; ! 425: p->refc = 0; ! 426: } ! 427: for (p = first.forw; p!=0; p = p->forw) { ! 428: if (p->combop==JBR || p->op==CBR || p->op==JSW || p->op==JMP ! 429: || p->op==SOBGEQ || p->op==SOBGTR || p->op==AOBLEQ || p->op==AOBLSS ! 430: || p->op==ACB || (p->op==MOVA && p->labno!=0)) { ! 431: p->ref = 0; ! 432: lp = labhash[p->labno % LABHS]; ! 433: if (lp==0 || p->labno!=lp->labno) ! 434: for (lp = first.forw; lp!=0; lp = lp->forw) { ! 435: if (lp->op==LABEL && p->labno==lp->labno) ! 436: break; ! 437: } ! 438: if (lp) { ! 439: hp = nonlab(lp)->back; ! 440: if (hp!=lp) { ! 441: p->labno = hp->labno; ! 442: lp = hp; ! 443: } ! 444: p->ref = lp; ! 445: lp->refc++; ! 446: } ! 447: } ! 448: } ! 449: for (p = first.forw; p!=0; p = p->forw) ! 450: if (p->op==LABEL && p->refc==0 ! 451: && (lp = nonlab(p))->op && lp->op!=JSW) ! 452: decref(p); ! 453: } ! 454: ! 455: iterate() ! 456: { ! 457: register struct node *p, *rp, *p1; ! 458: ! 459: nchange = 0; ! 460: for (p = first.forw; p!=0; p = p->forw) { ! 461: if ((p->op==JBR||p->op==CBR||p->op==JSW) && p->ref) { ! 462: rp = nonlab(p->ref); ! 463: if (rp->op==JBR && rp->labno && p->labno!=rp->labno) { ! 464: nbrbr++; ! 465: p->labno = rp->labno; ! 466: decref(p->ref); ! 467: rp->ref->refc++; ! 468: p->ref = rp->ref; ! 469: nchange++; ! 470: } ! 471: } ! 472: #ifndef COPYCODE ! 473: if (p->op==CBR && (p1 = p->forw)->combop==JBR) {/* combop: RET problems */ ! 474: #else ! 475: if (p->op==CBR && (p1 = p->forw)->combop==JBR && ! 476: p->ref) {/* combop: RET problems */ ! 477: #endif ! 478: rp = p->ref; ! 479: do ! 480: rp = rp->back; ! 481: while (rp->op==LABEL); ! 482: if (rp==p1) { ! 483: decref(p->ref); ! 484: p->ref = p1->ref; ! 485: p->labno = p1->labno; ! 486: #ifdef COPYCODE ! 487: if (p->labno == 0) ! 488: p->code = p1->code; ! 489: #endif ! 490: p1->forw->back = p; ! 491: p->forw = p1->forw; ! 492: p->subop = revbr[p->subop]; ! 493: p->pop=0; ! 494: nchange++; ! 495: nskip++; ! 496: } ! 497: } ! 498: if (p->op==JBR || p->op==JMP) { ! 499: while (p->forw && p->forw->op!=LABEL && p->forw->op!=DLABEL ! 500: && p->forw->op!=EROU && p->forw->op!=END ! 501: && p->forw->op!=ALIGN ! 502: && p->forw->op!=0 && p->forw->op!=DATA) { ! 503: nchange++; ! 504: iaftbr++; ! 505: if (p->forw->ref) ! 506: decref(p->forw->ref); ! 507: p->forw = p->forw->forw; ! 508: p->forw->back = p; ! 509: } ! 510: rp = p->forw; ! 511: while (rp && rp->op==LABEL) { ! 512: if (p->ref == rp) { ! 513: p->back->forw = p->forw; ! 514: p->forw->back = p->back; ! 515: p = p->back; ! 516: decref(rp); ! 517: nchange++; ! 518: njp1++; ! 519: break; ! 520: } ! 521: rp = rp->forw; ! 522: } ! 523: xjump(p); ! 524: p = codemove(p); ! 525: } ! 526: } ! 527: } ! 528: ! 529: xjump(p1) ! 530: register struct node *p1; ! 531: { ! 532: register struct node *p2, *p3; ! 533: int nxj; ! 534: ! 535: nxj = 0; ! 536: if ((p2 = p1->ref)==0) ! 537: return(0); ! 538: for (;;) { ! 539: while ((p1 = p1->back) && p1->op==LABEL); ! 540: while ((p2 = p2->back) && p2->op==LABEL); ! 541: if (!equop(p1, p2) || p1==p2) ! 542: return(nxj); ! 543: p3 = insertl(p2); ! 544: p1->combop = JBR; ! 545: p1->pop=0; ! 546: p1->ref = p3; ! 547: p1->labno = p3->labno; ! 548: p1->code = 0; ! 549: nxj++; ! 550: nxjump++; ! 551: nchange++; ! 552: } ! 553: } ! 554: ! 555: struct node * ! 556: insertl(op) ! 557: register struct node *op; ! 558: { ! 559: register struct node *lp; ! 560: ! 561: if (op->op == LABEL) { ! 562: op->refc++; ! 563: return(op); ! 564: } ! 565: if (op->back->op == LABEL) { ! 566: op = op->back; ! 567: op->refc++; ! 568: return(op); ! 569: } ! 570: lp = alloc(sizeof first); ! 571: lp->combop = LABEL; ! 572: lp->labno = isn++; ! 573: lp->ref = 0; ! 574: lp->code = 0; ! 575: lp->refc = 1; ! 576: lp->back = op->back; ! 577: lp->forw = op; ! 578: op->back->forw = lp; ! 579: op->back = lp; ! 580: return(lp); ! 581: } ! 582: ! 583: struct node * ! 584: codemove(ap) ! 585: struct node *ap; ! 586: { ! 587: register struct node *p1, *p2, *p3; ! 588: struct node *t, *tl; ! 589: int n; ! 590: ! 591: p1 = ap; ! 592: /* last clause to avoid infinite loop on partial compiler droppings: ! 593: L183: jbr L179 ! 594: L191: jbr L179 ! 595: casel r0,$0,$1 ! 596: L193: .word L183-L193 ! 597: .word L191-L193 ! 598: L179: ret ! 599: */ ! 600: if (p1->op!=JBR || (p2 = p1->ref)==0 || p2==p1->forw) ! 601: return(p1); ! 602: while (p2->op == LABEL) ! 603: if ((p2 = p2->back) == 0) ! 604: return(p1); ! 605: if (p2->op!=JBR && p2->op!=JMP) ! 606: goto ivloop; ! 607: p2 = p2->forw; ! 608: p3 = p1->ref; ! 609: while (p3) { ! 610: if (p3->op==JBR || p3->op==JMP) { ! 611: if (p1==p3) ! 612: return(p1); ! 613: ncmot++; ! 614: nchange++; ! 615: p1->back->forw = p2; ! 616: p1->forw->back = p3; ! 617: p2->back->forw = p3->forw; ! 618: p3->forw->back = p2->back; ! 619: p2->back = p1->back; ! 620: p3->forw = p1->forw; ! 621: decref(p1->ref); ! 622: return(p2); ! 623: } else ! 624: p3 = p3->forw; ! 625: } ! 626: return(p1); ! 627: ivloop: ! 628: if (p1->forw->op!=LABEL) ! 629: return(p1); ! 630: p3 = p2 = p2->forw; ! 631: n = 16; ! 632: do { ! 633: if ((p3 = p3->forw) == 0 || p3==p1 || --n==0) ! 634: return(p1); ! 635: } while (p3->op!=CBR || p3->labno!=p1->forw->labno); ! 636: do ! 637: if ((p1 = p1->back) == 0) ! 638: return(ap); ! 639: while (p1!=p3); ! 640: p1 = ap; ! 641: tl = insertl(p1); ! 642: p3->subop = revbr[p3->subop]; ! 643: p3->pop=0; ! 644: decref(p3->ref); ! 645: p2->back->forw = p1; ! 646: p3->forw->back = p1; ! 647: p1->back->forw = p2; ! 648: p1->forw->back = p3; ! 649: t = p1->back; ! 650: p1->back = p2->back; ! 651: p2->back = t; ! 652: t = p1->forw; ! 653: p1->forw = p3->forw; ! 654: p3->forw = t; ! 655: p2 = insertl(p1->forw); ! 656: p3->labno = p2->labno; ! 657: #ifdef COPYCODE ! 658: if (p3->labno == 0) ! 659: p3->code = p2->code; ! 660: #endif ! 661: p3->ref = p2; ! 662: decref(tl); ! 663: if (tl->refc<=0) ! 664: nrlab--; ! 665: loopiv++; ! 666: nchange++; ! 667: return(p3); ! 668: } ! 669: ! 670: comjump() ! 671: { ! 672: register struct node *p1, *p2, *p3; ! 673: ! 674: for (p1 = first.forw; p1!=0; p1 = p1->forw) ! 675: if (p1->op==JBR && ((p2 = p1->ref) && p2->refc > 1 ! 676: || p1->subop==RET || p1->subop==RSB)) ! 677: for (p3 = p1->forw; p3!=0; p3 = p3->forw) ! 678: if (p3->op==JBR && p3->ref == p2) ! 679: backjmp(p1, p3); ! 680: } ! 681: ! 682: backjmp(ap1, ap2) ! 683: struct node *ap1, *ap2; ! 684: { ! 685: register struct node *p1, *p2, *p3; ! 686: ! 687: p1 = ap1; ! 688: p2 = ap2; ! 689: for(;;) { ! 690: while ((p1 = p1->back) && p1->op==LABEL); ! 691: p2 = p2->back; ! 692: if (equop(p1, p2)) { ! 693: p3 = insertl(p1); ! 694: p2->back->forw = p2->forw; ! 695: p2->forw->back = p2->back; ! 696: p2 = p2->forw; ! 697: decref(p2->ref); ! 698: p2->combop = JBR; /* to handle RET */ ! 699: p2->pop=0; ! 700: p2->labno = p3->labno; ! 701: #ifdef COPYCODE ! 702: p2->code = 0; ! 703: #endif ! 704: p2->ref = p3; ! 705: nchange++; ! 706: ncomj++; ! 707: } else ! 708: return; ! 709: } ! 710: }
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