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Lemon collapses common destructors and reduce actions into a single case. (CVS 1837)
FossilOrigin-Name: 3c5aa850eeec5c75c5200a3707852cc5fc9e780b
This commit is contained in:
drh
190
tool/lemon.c
190
tool/lemon.c
@ -2999,6 +2999,115 @@ struct lemon *lemp;
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return ret;
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}
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/*
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** Append text to a dynamically allocated string. If zText is 0 then
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** reset the string to be empty again. Always return the complete text
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** of the string (which is overwritten with each call).
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*/
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PRIVATE char *append_str(char *zText, int n, int p1, int p2){
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static char *z = 0;
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static int alloced = 0;
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static int used = 0;
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int i, c;
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char zInt[40];
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if( zText==0 ){
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used = 0;
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return z;
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}
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if( n<=0 ) n = strlen(zText);
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if( n+sizeof(zInt)*2+used >= alloced ){
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alloced = n + sizeof(zInt)*2 + used + 200;
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z = realloc(z, alloced);
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}
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if( z==0 ) return "";
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while( n-- > 0 ){
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c = *(zText++);
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if( c=='%' && zText[0]=='d' ){
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sprintf(zInt, "%d", p1);
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p1 = p2;
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strcpy(&z[used], zInt);
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used += strlen(&z[used]);
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zText++;
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n--;
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}else{
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z[used++] = c;
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}
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}
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z[used] = 0;
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return z;
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}
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/*
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** zCode is a string that is the action associated with a rule. Expand
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** the symbols in this string so that the refer to elements of the parser
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** stack. Return a new string stored in space obtained from malloc.
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*/
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PRIVATE char *translate_code(struct lemon *lemp, struct rule *rp){
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char *cp, *xp;
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int i;
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char lhsused = 0; /* True if the LHS element has been used */
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char used[MAXRHS]; /* True for each RHS element which is used */
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for(i=0; i<rp->nrhs; i++) used[i] = 0;
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lhsused = 0;
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append_str(0,0,0,0);
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for(cp=rp->code; *cp; cp++){
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if( isalpha(*cp) && (cp==rp->code || (!isalnum(cp[-1]) && cp[-1]!='_')) ){
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char saved;
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for(xp= &cp[1]; isalnum(*xp) || *xp=='_'; xp++);
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saved = *xp;
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*xp = 0;
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if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){
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append_str("yygotominor.yy%d",-1,rp->lhs->dtnum,0);
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cp = xp;
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lhsused = 1;
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}else{
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for(i=0; i<rp->nrhs; i++){
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if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){
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append_str("yymsp[%d].minor.yy%d",-1,
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i-rp->nrhs+1,rp->rhs[i]->dtnum);
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cp = xp;
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used[i] = 1;
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break;
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}
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}
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}
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*xp = saved;
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}
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append_str(cp, 1, 0, 0);
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} /* End loop */
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/* Check to make sure the LHS has been used */
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if( rp->lhsalias && !lhsused ){
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ErrorMsg(lemp->filename,rp->ruleline,
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"Label \"%s\" for \"%s(%s)\" is never used.",
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rp->lhsalias,rp->lhs->name,rp->lhsalias);
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lemp->errorcnt++;
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}
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/* Generate destructor code for RHS symbols which are not used in the
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** reduce code */
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for(i=0; i<rp->nrhs; i++){
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if( rp->rhsalias[i] && !used[i] ){
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ErrorMsg(lemp->filename,rp->ruleline,
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"Label %s for \"%s(%s)\" is never used.",
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rp->rhsalias[i],rp->rhs[i]->name,rp->rhsalias[i]);
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lemp->errorcnt++;
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}else if( rp->rhsalias[i]==0 ){
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if( has_destructor(rp->rhs[i],lemp) ){
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append_str(" yy_destructor(%d,&yymsp[%d].minor);\n", -1,
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rp->rhs[i]->index,i-rp->nrhs+1);
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}else{
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/* No destructor defined for this term */
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}
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}
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}
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cp = append_str(0,0,0,0);
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rp->code = Strsafe(cp);
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}
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/*
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** Generate code which executes when the rule "rp" is reduced. Write
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** the code to "out". Make sure lineno stays up-to-date.
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@ -3009,74 +3118,20 @@ struct rule *rp;
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struct lemon *lemp;
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int *lineno;
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{
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char *cp, *xp;
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char *cp;
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int linecnt = 0;
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int i;
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char lhsused = 0; /* True if the LHS element has been used */
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char used[MAXRHS]; /* True for each RHS element which is used */
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for(i=0; i<rp->nrhs; i++) used[i] = 0;
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lhsused = 0;
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/* Generate code to do the reduce action */
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if( rp->code ){
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fprintf(out,"#line %d \"%s\"\n{",rp->line,lemp->filename);
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fprintf(out,"%s",rp->code);
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for(cp=rp->code; *cp; cp++){
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if( isalpha(*cp) && (cp==rp->code || (!isalnum(cp[-1]) && cp[-1]!='_')) ){
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char saved;
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for(xp= &cp[1]; isalnum(*xp) || *xp=='_'; xp++);
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saved = *xp;
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*xp = 0;
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if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){
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fprintf(out,"yygotominor.yy%d",rp->lhs->dtnum);
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cp = xp;
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lhsused = 1;
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}else{
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for(i=0; i<rp->nrhs; i++){
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if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){
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fprintf(out,"yymsp[%d].minor.yy%d",i-rp->nrhs+1,rp->rhs[i]->dtnum);
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cp = xp;
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used[i] = 1;
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break;
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}
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}
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}
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*xp = saved;
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}
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if( *cp=='\n' ) linecnt++;
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fputc(*cp,out);
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} /* End loop */
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(*lineno) += 3 + linecnt;
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fprintf(out,"}\n#line %d \"%s\"\n",*lineno,lemp->outname);
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} /* End if( rp->code ) */
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/* Check to make sure the LHS has been used */
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if( rp->lhsalias && !lhsused ){
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ErrorMsg(lemp->filename,rp->ruleline,
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"Label \"%s\" for \"%s(%s)\" is never used.",
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rp->lhsalias,rp->lhs->name,rp->lhsalias);
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lemp->errorcnt++;
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}
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/* Generate destructor code for RHS symbols which are not used in the
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** reduce code */
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for(i=0; i<rp->nrhs; i++){
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if( rp->rhsalias[i] && !used[i] ){
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ErrorMsg(lemp->filename,rp->ruleline,
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"Label %s for \"%s(%s)\" is never used.",
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rp->rhsalias[i],rp->rhs[i]->name,rp->rhsalias[i]);
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lemp->errorcnt++;
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}else if( rp->rhsalias[i]==0 ){
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if( has_destructor(rp->rhs[i],lemp) ){
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fprintf(out," yy_destructor(%d,&yymsp[%d].minor);\n",
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rp->rhs[i]->index,i-rp->nrhs+1); (*lineno)++;
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}else{
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fprintf(out," /* No destructor defined for %s */\n",
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rp->rhs[i]->name);
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(*lineno)++;
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}
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}
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}
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return;
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}
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@ -3569,6 +3624,18 @@ int mhflag; /* Output in makeheaders format if true */
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struct symbol *sp = lemp->symbols[i];
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if( sp==0 || sp->type==TERMINAL || sp->destructor==0 ) continue;
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fprintf(out," case %d:\n",sp->index); lineno++;
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/* Combine duplicate destructors into a single case */
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for(j=i+1; j<lemp->nsymbol; j++){
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struct symbol *sp2 = lemp->symbols[j];
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if( sp2 && sp2->type!=TERMINAL && sp2->destructor
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&& sp2->dtnum==sp->dtnum
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&& strcmp(sp->destructor,sp2->destructor)==0 ){
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fprintf(out," case %d:\n",sp2->index); lineno++;
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sp2->destructor = 0;
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}
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}
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emit_destructor_code(out,lemp->symbols[i],lemp,&lineno);
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fprintf(out," break;\n"); lineno++;
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}
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@ -3604,7 +3671,18 @@ int mhflag; /* Output in makeheaders format if true */
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/* Generate code which execution during each REDUCE action */
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for(rp=lemp->rule; rp; rp=rp->next){
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if( rp->code ) translate_code(lemp, rp);
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}
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for(rp=lemp->rule; rp; rp=rp->next){
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struct rule *rp2;
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if( rp->code==0 ) continue;
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fprintf(out," case %d:\n",rp->index); lineno++;
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for(rp2=rp->next; rp2; rp2=rp2->next){
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if( rp2->code==rp->code ){
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fprintf(out," case %d:\n",rp2->index); lineno++;
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rp2->code = 0;
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}
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}
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emit_code(out,rp,lemp,&lineno);
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fprintf(out," break;\n"); lineno++;
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}
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