# /* * C object code improver-- second part */ #include "c2.h" rmove() { register struct node *p; register int r; register r1, flt; for (p=first.forw; p!=0; p = p->forw) { flt = 0; switch (p->op) { case MOVF: case MOVFO: case MOVOF: flt = NREG; case MOV: if (p->subop==BYTE) goto dble; dualop(p); if ((r = findrand(regs[RT1], flt)) >= 0) { if (r == flt+isreg(regs[RT2]) && p->forw->op!=CBR && p->forw->op!=SXT && p->forw->op!=CFCC) { p->forw->back = p->back; p->back->forw = p->forw; redunm++; nchange++; continue; } } if (equstr(regs[RT1], "$0")) { p->op = CLR; strcpy(regs[RT1], regs[RT2]); regs[RT2][0] = 0; p->code = copy(1, regs[RT1]); nchange++; goto sngl; } repladdr(p, 0, flt); r = isreg(regs[RT1]); r1 = isreg(regs[RT2]); dest(regs[RT2], flt); if (r >= 0) if (r1 >= 0) savereg(r1+flt, regs[r+flt]); else savereg(r+flt, regs[RT2]); else if (r1 >= 0) savereg(r1+flt, regs[RT1]); else setcon(regs[RT1], regs[RT2]); source(regs[RT1]); setcc(regs[RT2]); continue; case ADDF: case SUBF: case DIVF: case MULF: flt = NREG; goto dble; case ADD: case SUB: case BIC: case BIS: case MUL: case DIV: case ASH: dble: dualop(p); if (p->op==BIC && (equstr(regs[RT1], "$-1") || equstr(regs[RT1], "$177777"))) { p->op = CLR; strcpy(regs[RT1], regs[RT2]); regs[RT2][0] = 0; p->code = copy(1, regs[RT1]); nchange++; goto sngl; } if ((p->op==BIC || p->op==BIS) && equstr(regs[RT1], "$0")) { if (p->forw->op!=CBR) { p->back->forw = p->forw; p->forw->back = p->back; nchange++; continue; } } /* * the next block of code looks for the sequences (which extract the * high byte of a word or the low byte respectively): * ash $-10,r * bic $-400,r * or * mov natural,r * bic $-400,r * and transforms them into: * clrb r * swab r * or * clr r * bisb natural,r * These constructs occur often enough in the kernel (dealing with major/minor * device numbers, etc) it's worth a little extra work at compile time. */ if (p->op == BIC && (equstr(regs[RT1],"$-400") || equstr(regs[RT1],"$-177400"))) { if (p->back->op == ASH) { r = isreg(regs[RT2]); dualop(p->back); if ((equstr(regs[RT1], "$-10") || equstr(regs[RT1], "$177770")) && r == isreg(regs[RT2])) { strcpy(regs[RT1], regs[RT2]); regs[RT2][0] = 0; p->back->op = CLR; p->back->subop = BYTE; p->back->code = copy(1, regs[RT1]); p->op = SWAB; p->code = copy(1, regs[RT1]); nchange++; goto sngl; } } else if (p->back->op == MOV && p->forw->op != CBR) { char temp[50]; r = isreg(regs[RT2]); if (r < 0 && !xnatural(regs[RT2])) goto out; strcpy(temp, regs[RT2]); dualop(p->back); if (isreg(regs[RT2]) == r && natural(regs[RT1])) { if (r < 0 && (!xnatural(regs[RT2]) || !equstr(temp, regs[RT2]))) goto out; /* * XXX - the sequence "movb rN,rN; bic $-400,rN" can not be transformed * because the 'clr' would lose all information about 'rN'. The best that can * be done is to remove the 'movb' instruction and leave the 'bic'. */ if (isreg(regs[RT1]) == r && r >= 0) { p = p->back; p->forw->back = p->back; p->back->forw = p->forw; nchange++; continue; } dest(regs[RT1], flt); p->back->op = CLR; p->back->subop = 0; p->back->code = copy(1, regs[RT2]); p->op = BIS; p->subop = BYTE; strcat(regs[RT1], ","); p->code = copy(2, regs[RT1], regs[RT2]); nchange++; } } out: dualop(p); /* restore banged up parsed operands */ } repladdr(p, 0, flt); source(regs[RT1]); dest(regs[RT2], flt); if (p->op==DIV && (r = isreg(regs[RT2]))>=0) regs[r|1][0] = 0; switch (p->op) { case ADD: case SUB: case BIC: case BIS: case ASH: setcc(regs[RT2]); break; default: ccloc[0] = 0; } continue; case SXT: singop(p); if (p->forw->op == CLR && p->forw->subop != BYTE && xnatural(regs[RT1]) && !strcmp(p->code, p->forw->code)){ p->forw->back = p->back; p->back->forw = p->forw; nchange++; continue; } goto sngl; case CLRF: case NEGF: flt = NREG; case CLR: case COM: case INC: case DEC: case NEG: case ASR: case ASL: case SWAB: singop(p); sngl: dest(regs[RT1], flt); if (p->op==CLR && flt==0) { if ((r = isreg(regs[RT1])) >= 0) savereg(r, "$0"); else setcon("$0", regs[RT1]); ccloc[0] = 0; } else setcc(regs[RT1]); continue; case TSTF: flt = NREG; case TST: singop(p); repladdr(p, 0, flt); source(regs[RT1]); if (p->back->op == TST && !flt && not_sp(regs[RT1])) { char rt1[MAXCPS + 2]; strcpy(rt1, regs[RT1]); singop(p->back); if (!strcmp("(sp)+", regs[RT1])) { p->back->subop = p->subop; p->back->forw = p->forw; p->forw->back = p->back; p = p->back; p->op = MOV; p->code = copy(2, rt1, ",(sp)+"); nrtst++; nchange++; continue; } singop(p); } if (p->back->op == MOV && p->back->subop == BYTE) { dualop(p->back); setcc(regs[RT2]); singop(p); } if (equstr(regs[RT1], ccloc) && p->subop == p->back->subop) { p->back->forw = p->forw; p->forw->back = p->back; p = p->back; nrtst++; nchange++; } else setcc(regs[RT1]); /* XXX - double TST in a row */ continue; case CMPF: flt = NREG; case CMP: case BIT: dualop(p); source(regs[RT1]); source(regs[RT2]); if(p->op==BIT) { if (equstr(regs[RT1], "$-1") || equstr(regs[RT1], "$177777")) { p->op = TST; strcpy(regs[RT1], regs[RT2]); regs[RT2][0] = 0; p->code = copy(1, regs[RT1]); nchange++; nsaddr++; } else if (equstr(regs[RT2], "$-1") || equstr(regs[RT2], "$177777")) { p->op = TST; regs[RT2][0] = 0; p->code = copy(1, regs[RT1]); nchange++; nsaddr++; } if (equstr(regs[RT1], "$0")) { p->op = TST; regs[RT2][0] = 0; p->code = copy(1, regs[RT1]); nchange++; nsaddr++; } else if (equstr(regs[RT2], "$0")) { p->op = TST; strcpy(regs[RT1], regs[RT2]); regs[RT2][0] = 0; p->code = copy(1, regs[RT1]); nchange++; nsaddr++; } } repladdr(p, 1, flt); ccloc[0] = 0; continue; case CBR: r = -1; if (p->back->op==TST || p->back->op==CMP) { if (p->back->op==TST) { singop(p->back); savereg(RT2, "$0"); } else dualop(p->back); if (equstr(regs[RT1], regs[RT2]) && natural(regs[RT1]) && natural(regs[RT2])) r = compare(p->subop, "$1", "$1"); else r = compare(p->subop, findcon(RT1), findcon(RT2)); if (r==0) { if (p->forw->op==CBR || p->forw->op==SXT || p->forw->op==CFCC) { p->back->forw = p->forw; p->forw->back = p->back; } else { p->back->back->forw = p->forw; p->forw->back = p->back->back; } decref(p->ref); p = p->back->back; nchange++; } else if (r>0) { p->op = JBR; p->subop = 0; p->back->back->forw = p; p->back = p->back->back; p = p->back; nchange++; } /* * If the instruction prior to the conditional branch was a 'tst' then * save the condition code status. The C construct: * if (x) * if (x > 0) * generates "tst _x; jeq ...; tst _x; jmi ...;jeq ...". The code below removes * the second "tst _x", leaving "tst _x; jeq ...;jmi ...; jeq ...". */ if (p->back->op == TST) { singop(p->back); setcc(regs[RT1]); break; } } /* * If the previous instruction was also a conditional branch then * attempt to merge the two into a single branch. */ if (p->back->op == CBR) fixupbr(p); case CFCC: ccloc[0] = 0; continue; /* * Unrecognized (unparsed) instructions, assignments (~foo=r2), and * data arrive here. In order to prevent throwing away information * about register contents just because a local assignment is done * we check for the first character being a tilde. */ case 0: if (p->code[0] != '~') clearreg(); continue; case JBR: redunbr(p); default: clearreg(); } } } /* * This table is used to convert two branches to the same label after a * 'tst' (which clears the C and V condition codes) into a single branch. * Entries which translate to JBR could eventually cause the 'tst' instruction * to be eliminated as well, but that can wait for now. There are unused or * impossible combinations ('tst' followed by 'jlo' for example. since * 'tst' clears C it makes little sense to 'jlo/bcs') in the table, it * would have cost more in code to remove them than the entries themselves. * * Example: "tst _x; jmi L3; jeq L3". Find the row for 'jmi', then look * at the column for 'jeq', the resulting "opcode" is 'jle'. */ char brtable[12][12] = { /* jeq jne jle jge jlt jgt jlo jhi jlos jhis jpl jmi */ /* jeq */ {JEQ ,JBR ,JLE ,JGE ,JLE ,JGE ,JEQ ,JBR ,JEQ ,JBR ,JGE ,JLE}, /* jne */ {JBR ,JNE ,JBR ,JBR ,JNE ,JNE ,JNE ,JNE ,JBR ,JBR ,JBR ,JNE}, /* jle */ {JLE ,JBR ,JLE ,JBR ,JLE ,JBR ,JLE ,JBR ,JLE ,JBR ,JBR ,JLE}, /* jge */ {JGE ,JBR ,JBR ,JGE ,JBR ,JGE ,JGE ,JBR ,JGE ,JBR ,JGE ,JBR}, /* jlt */ {JLE ,JNE ,JLE ,JBR ,JLT ,JNE ,JLT ,JBR ,JLE ,JBR ,JBR ,JLT}, /* jgt */ {JGE ,JNE ,JBR ,JGE ,JNE ,JGT ,JGT ,JGT ,JBR ,JGE ,JGE ,JNE}, /* jlo */ {JEQ ,JNE ,JLE ,JGE ,JLT ,JGT ,JLO ,JHI ,JLOS,JHIS,JPL ,JMI}, /* jhi */ {JBR ,JNE ,JBR ,JBR ,JNE ,JNE ,JNE ,JNE ,JBR ,JBR ,JBR ,JNE}, /* jlos*/ {JEQ ,JBR ,JLE ,JGE ,JLE ,JGE ,JLE ,JBR ,JEQ ,JBR ,JGE ,JLE}, /* jhis*/ {JBR ,JBR ,JBR ,JBR ,JBR ,JBR ,JBR ,JBR ,JBR ,JBR ,JBR ,JBR}, /* jpl */ {JGE ,JBR ,JBR ,JGE ,JBR ,JGE ,JGE ,JBR ,JGE ,JBR ,JGE ,JBR}, /* jmi */ {JLE ,JNE ,JLE ,JBR ,JLT ,JNE ,JLT ,JNE ,JLE ,JLT ,JBR ,JLT} }; fixupbr(p) register struct node *p; { register struct node *p1, *p2; int op; p1 = p->back; p2 = p1->back; if (p->labno != p1->labno) return; if (p2->op != TST) { if (p2->op == CBR && p2->back->op == TST) goto ok; return; } ok: p->subop = brtable[p->subop][p1->subop]; nchange++; nredunj++; p2->forw = p; p->back = p1->back; } jumpsw() { register struct node *p, *p1; register t; register struct node *tp; int nj; t = 0; nj = 0; for (p=first.forw; p!=0; p = p->forw) p->refc = ++t; for (p=first.forw; p!=0; p = p1) { p1 = p->forw; if (p->op == CBR && p1->op==JBR && p->ref && p1->ref && abs(p->refc - p->ref->refc) > abs(p1->refc - p1->ref->refc)) { if (p->ref==p1->ref) continue; p->subop = revbr[p->subop]; tp = p1->ref; p1->ref = p->ref; p->ref = tp; t = p1->labno; p1->labno = p->labno; p->labno = t; nrevbr++; nj++; } } return(nj); } addsob() { register struct node *p, *p1; for (p = &first; (p1 = p->forw)!=0; p = p1) { if (p->op==DEC && isreg(p->code)>=0 && p1->op==CBR && p1->subop==JNE) { if (p->refc < p1->ref->refc) continue; if (toofar(p1)) continue; p->labno = p1->labno; p->op = SOB; p->subop = 0; p1->forw->back = p; p->forw = p1->forw; nsob++; } } } toofar(p) struct node *p; { register struct node *p1; int len; len = 0; for (p1 = p->ref; p1 && p1!=p; p1 = p1->forw) len += ilen(p1); if (len < 128) return(0); return(1); } ilen(p) register struct node *p; { switch (p->op) { case LABEL: case DLABEL: case TEXT: case EROU: case EVEN: return(0); case CBR: return(6); default: dualop(p); return(2 + adrlen(regs[RT1]) + adrlen(regs[RT2])); } } adrlen(s) register char *s; { if (*s == 0) return(0); if (*s=='r') return(0); if (*s=='(' && *(s+1)=='r') return(0); if (*s=='-' && *(s+1)=='(') return(0); return(2); } abs(x) register int x; { return(x<0? -x: x); } equop(ap1, p2) struct node *ap1, *p2; { register char *cp1, *cp2; register struct node *p1; p1 = ap1; if (p1->op!=p2->op || p1->subop!=p2->subop) return(0); if (p1->op>0 && p1->opcode; cp2 = p2->code; if (cp1==0 && cp2==0) return(1); if (cp1==0 || cp2==0) return(0); while (*cp1 == *cp2++) if (*cp1++ == 0) return(1); return(0); } decref(p) register struct node *p; { if (--p->refc <= 0) { nrlab++; p->back->forw = p->forw; p->forw->back = p->back; } } struct node * nonlab(p) register struct node *p; { CHECK(10); while (p && p->op==LABEL) p = p->forw; return(p); } char * alloc(n) register n; { register char *p; #define round(a,b) ((((a)+(b)-1)/(b))*(b)) n=round(n,sizeof(char *)); if (alasta+n < alastr) { p = alasta; alasta += n; return(p); } if (lasta+n >= lastr) { if (sbrk(2000) == (char *)-1) { fprintf(stderr, "C Optimizer: out of space\n"); exit(1); } lastr += 2000; } p = lasta; lasta += n; return(p); } clearreg() { register int i; for (i=0; i<2*NREG; i++) regs[i][0] = '\0'; conloc[0] = 0; ccloc[0] = 0; } savereg(ai, as) char *as; { register char *p, *s, *sp; sp = p = regs[ai]; s = as; if (source(s)) return; while (*p++ = *s) { if (s[0]=='(' && s[1]=='r' && s[2]<'5') { *sp = 0; return; } if (*s++ == ',') break; } *--p = '\0'; } dest(as, flt) char *as; { register char *s; register int i; s = as; source(s); if ((i = isreg(s)) >= 0) regs[i+flt][0] = 0; /* v7orig: * for (i=0; i= 0) regs[i][0] = 0; while (*s) { if ((*s=='(' && (*(s+1)!='r' || *(s+2)!='5')) || *s++=='*') { /* v7.orig: * for (i=0; icode; p2 = regs[RT1]; while (*p2++ = *p1++); regs[RT2][0] = 0; } dualop(ap) struct node *ap; { register char *p1, *p2; register struct node *p; p = ap; p1 = p->code; p2 = regs[RT1]; while (*p1 && *p1!=',') *p2++ = *p1++; *p2++ = 0; p2 = regs[RT2]; *p2 = 0; if (*p1++ !=',') return; while (*p1==' ' || *p1=='\t') p1++; while (*p2++ = *p1++) ; } findrand(as, flt) char *as; { register int i; for (i = flt; i='0' && s[1]<='4' && s[2]==0) return(s[1]-'0'); return(-1); } check() { register struct node *p, *lp; register count; lp = &first; count = 0; for (p=first.forw; p!=0; p = p->forw) { if (++count > 10000) abort(0); if (p->back != lp) abort(1); lp = p; } } source(ap) char *ap; { register char *p1, *p2; p1 = ap; p2 = p1; if (*p1==0) return(0); while (*p2++); if (*p1=='-' && *(p1+1)=='(' || *p1=='*' && *(p1+1)=='-' && *(p1+2)=='(' || *(p2-2)=='+') { while (*p1 && *p1++!='r'); if (*p1>='0' && *p1<='4') regs[*p1 - '0'][0] = 0; return(1); } return(0); } repladdr(p, f, flt) struct node *p; { register r; int r1; register char *p1, *p2; static char rt1[50], rt2[50]; if (f) r1 = findrand(regs[RT2], flt); else r1 = -1; r = findrand(regs[RT1], flt); if (r1 >= NREG) r1 -= NREG; if (r >= NREG) r -= NREG; if (r>=0 || r1>=0) { p2 = regs[RT1]; for (p1 = rt1; *p1++ = *p2++;); if (regs[RT2][0]) { p1 = rt2; *p1++ = ','; for (p2 = regs[RT2]; *p1++ = *p2++;); } else rt2[0] = 0; if (r>=0) { rt1[0] = 'r'; rt1[1] = r + '0'; rt1[2] = 0; nsaddr++; nchange++; } if (r1>=0) { rt2[1] = 'r'; rt2[2] = r1 + '0'; rt2[3] = 0; nsaddr++; nchange++; } p->code = copy(2, rt1, rt2); } } movedat() { register struct node *p1, *p2; struct node *p3; register seg; struct node data; struct node *datp; if (first.forw == 0) return; if (lastseg != TEXT && lastseg != -1) { p1 = (struct node *)alloc(sizeof(first)); p1->op = lastseg; p1->subop = 0; p1->code = NULL; p1->forw = first.forw; p1->back = &first; first.forw->back = p1; first.forw = p1; } datp = &data; for (p1 = first.forw; p1!=0; p1 = p1->forw) { if (p1->op == DATA) { p2 = p1->forw; while (p2 && p2->op!=TEXT) p2 = p2->forw; if (p2==0) break; p3 = p1->back; p1->back->forw = p2->forw; p2->forw->back = p3; p2->forw = 0; datp->forw = p1; p1->back = datp; p1 = p3; datp = p2; } } if (data.forw) { datp->forw = first.forw; first.forw->back = datp; data.forw->back = &first; first.forw = data.forw; } seg = lastseg; for (p1 = first.forw; p1!=0; p1 = p1->forw) { if (p1->op==TEXT||p1->op==DATA||p1->op==BSS) { if (p2 = p1->forw) { if (p2->op==TEXT||p2->op==DATA||p2->op==BSS) p1->op = p2->op; } if (p1->op == seg || p1->forw&&p1->forw->op==seg) { p1->back->forw = p1->forw; p1->forw->back = p1->back; p1 = p1->back; continue; } seg = p1->op; } } } redunbr(p) register struct node *p; { register struct node *p1; register char *ap1; char *ap2; if ((p1 = p->ref) == 0) return; p1 = nonlab(p1); if (p1->op==TST) { singop(p1); savereg(RT2, "$0"); } else if (p1->op==CMP) dualop(p1); else return; if (p1->forw->op!=CBR) return; ap1 = findcon(RT1); ap2 = findcon(RT2); p1 = p1->forw; if (compare(p1->subop, ap1, ap2)>0) { nredunj++; nchange++; decref(p->ref); p->ref = p1->ref; p->labno = p1->labno; p->ref->refc++; } } char * findcon(i) { register char *p; register r; p = regs[i]; if (*p=='$') return(p); if ((r = isreg(p)) >= 0) return(regs[r]); if (equstr(p, conloc)) return(conval); return(p); } compare(oper, cp1, cp2) register char *cp1, *cp2; { register unsigned n1, n2; if (*cp1++ != '$' || *cp2++ != '$') return(-1); n1 = 0; while (*cp2 >= '0' && *cp2 <= '7') { n1 <<= 3; n1 += *cp2++ - '0'; } n2 = n1; n1 = 0; while (*cp1 >= '0' && *cp1 <= '7') { n1 <<= 3; n1 += *cp1++ - '0'; } if (*cp1=='+') cp1++; if (*cp2=='+') cp2++; do { if (*cp1++ != *cp2) return(-1); } while (*cp2++); switch(oper) { case JEQ: return(n1 == n2); case JNE: return(n1 != n2); case JLE: return((int)n1 <= (int)n2); case JGE: return((int)n1 >= (int)n2); case JLT: return((int)n1 < (int)n2); case JGT: return((int)n1 > (int)n2); case JLO: return(n1 < n2); case JHI: return(n1 > n2); case JLOS: return(n1 <= n2); case JHIS: return(n1 >= n2); } return(-1); } setcon(ar1, ar2) char *ar1, *ar2; { register char *cl, *cv, *p; cl = ar2; cv = ar1; if (*cv != '$') return; if (!natural(cl)) return; p = conloc; while (*p++ = *cl++); p = conval; while (*p++ = *cv++); } equstr(ap1, ap2) char *ap1, *ap2; { register char *p1, *p2; p1 = ap1; p2 = ap2; do { if (*p1++ != *p2) return(0); } while (*p2++); return(1); } setcc(ap) char *ap; { register char *p, *p1; p = ap; if (!natural(p)) { ccloc[0] = 0; return; } p1 = ccloc; while (*p1++ = *p++); } natural(ap) char *ap; { register char *p; p = ap; if (*p=='*' || *p=='(' || *p=='-'&&*(p+1)=='(') return(0); while (*p++); p--; if (*--p == '+' || *p ==')' && *--p != '5') return(0); return(1); } xnatural(ap) char *ap; { if (natural(ap)) return(1); return(equstr("(sp)", ap)); } not_sp(ap) register char *ap; { char c; while (c = *ap++) if (c == '(') return(*ap == 's' && ap[1] == 'p'); return(1); }