#include	"l.h" voidreadundefs(char *f, int t){	int i, n;	Sym *s;	Biobuf *b;	char *l, buf[256], *fields[64]; 	if(f == nil)		return;	b = Bopen(f, OREAD);	if(b == nil){		diag("could not open %s: %r", f);		errorexit();	}	while((l = Brdline(b, '\n')) != nil){		n = Blinelen(b);		if(n >= sizeof(buf)){			diag("%s: line too long", f);			errorexit();		}		memmove(buf, l, n);		buf[n-1] = '\0';		n = getfields(buf, fields, nelem(fields), 1, " \t\r\n");		if(n == nelem(fields)){			diag("%s: bad format", f);			errorexit();		}		for(i = 0; i < n; i++){			s = lookup(fields[i], 0);			s->type = SXREF;			s->subtype = t;			if(t == SIMPORT)				nimports++;			else				nexports++;		}	}	Bterm(b);} voidundefsym(Sym *s){	int n; 	n = imports;	if(s->value != 0)		diag("value != 0 on SXREF");	if(n >= 1<<Rindex)		diag("import index %d out of range", n);	s->value = n<<Roffset;	s->type = SUNDEF;	imports++;} voidzerosig(char *sp){	Sym *s; 	s = lookup(sp, 0);	s->sig = 0;} voidimport(void){	int i;	Sym *s; 	for(i = 0; i < NHASH; i++)		for(s = hash[i]; s != S; s = s->link)			if(s->sig != 0 && s->type == SXREF && (nimports == 0 || s->subtype == SIMPORT)){				undefsym(s);				Bprint(&bso, "IMPORT: %s sig=%lux v=%lld\n", s->name, s->sig, (vlong)s->value);			}} voidckoff(Sym *s, long v){	if(v < 0 || v >= 1<<Roffset)		diag("relocation offset %ld for %s out of range", v, s->name);} static Prog*newdata(Sym *s, int o, int w, int t){	Prog *p; 	p = prg();	p->link = datap;	datap = p;	p->as = ADATA;	p->reg = w;	p->from.type = D_OREG;	p->from.name = t;	p->from.sym = s;	p->from.offset = o;	p->to.type = D_CONST;	p->to.name = D_NONE;	return p;} voidexport(void){	int i, j, n, off, nb, sv, ne;	Sym *s, *et, *str, **esyms;	Prog *p;	char buf[NSNAME], *t; 	n = 0;	for(i = 0; i < NHASH; i++)		for(s = hash[i]; s != S; s = s->link)			if(s->sig != 0 && s->type != SXREF && s->type != SUNDEF && (nexports == 0 || s->subtype == SEXPORT))				n++;	esyms = malloc(n*sizeof(Sym*));	ne = n;	n = 0;	for(i = 0; i < NHASH; i++)		for(s = hash[i]; s != S; s = s->link)			if(s->sig != 0 && s->type != SXREF && s->type != SUNDEF && (nexports == 0 || s->subtype == SEXPORT))				esyms[n++] = s;	for(i = 0; i < ne-1; i++)		for(j = i+1; j < ne; j++)			if(strcmp(esyms[i]->name, esyms[j]->name) > 0){				s = esyms[i];				esyms[i] = esyms[j];				esyms[j] = s;			} 	nb = 0;	off = 0;	et = lookup(EXPTAB, 0);	if(et->type != 0 && et->type != SXREF)		diag("%s already defined", EXPTAB);	et->type = SDATA;	str = lookup(".string", 0);	if(str->type == 0)		str->type = SDATA;	sv = str->value;	for(i = 0; i < ne; i++){		s = esyms[i];		Bprint(&bso, "EXPORT: %s sig=%lux t=%d\n", s->name, s->sig, s->type); 		/* signature */		p = newdata(et, off, sizeof(long), D_EXTERN);		off += sizeof(long);		p->to.offset = s->sig; 		/* address */		p = newdata(et, off, sizeof(long), D_EXTERN);		off += sizeof(long);		p->to.name = D_EXTERN;		p->to.sym = s; 		/* string */		t = s->name;		n = strlen(t)+1;		for(;;){			buf[nb++] = *t;			sv++;			if(nb >= NSNAME){				p = newdata(str, sv-NSNAME, NSNAME, D_STATIC);				p->to.type = D_SCONST;				p->to.sval = malloc(NSNAME);				memmove(p->to.sval, buf, NSNAME);				nb = 0;			}			if(*t++ == 0)				break;		} 		/* name */		p = newdata(et, off, sizeof(long), D_EXTERN);		off += sizeof(long);		p->to.name = D_STATIC;		p->to.sym = str;		p->to.offset = sv-n;	} 	if(nb > 0){		p = newdata(str, sv-nb, nb, D_STATIC);		p->to.type = D_SCONST;		p->to.sval = malloc(NSNAME);		memmove(p->to.sval, buf, nb);	} 	for(i = 0; i < 3; i++){		newdata(et, off, sizeof(long), D_EXTERN);		off += sizeof(long);	}	et->value = off;	if(sv == 0)		sv = 1;	str->value = sv;	exports = ne;	free(esyms);}