assyms.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

		case JXALIGN:		return("align");
		case JXQUESTIONABLE:	return("jxquestionable");
		case JXINACTIVE:	return("inactive");
		case JXTUNNEL:		return("tunnel");
		case OBSOLETE:		return("obsolete");
		case IGNOREBOUND:	return("ignorebound");
		case FORWARDSTAB:	return("forwardstab");
		case FLOATINGSTAB:	return("floatingstab");
		case FIXEDSTAB:		return("fixedstab");
		case LABELID:		return("labelid");
		case OKTOBUMP:		return("oktobump");
		case ISET:		return("iset");
		case ILSYM:		return("ilsym");
		default:		sprintf(tagbuff,"%d", tag);
					return(tagbuff);
	}
}
#endif /* DEBUG */

htaballoc()
{
	register	struct	hashdallop	*new;
	new = (struct hashdallop *)ClearCalloc(1, sizeof (struct hashdallop));
	if (htab == 0)
		htab = new;
	else {		/* add AFTER the 1st slot */
		new->h_next = htab->h_next;
		htab->h_next = new;
	}
}

#define 	HASHCLOGGED	(NHASH / 2)

/*
 *	Lookup a symbol stored in extern yytext.
 *	All strings passed in via extern yytext had better have
 *	a trailing null.  Strings are placed in yytext for hashing by
 *	syminstall() and by yylex();
 *
 *	We take pains to avoid function calls; this functdion
 *	is called quite frequently, and the calls overhead
 *	in the vax contributes significantly to the overall
 *	execution speed of as.
 */
struct symtab **lookup(instflg)
	int	instflg;		/* 0: don't install */
{
	static	 int		initialprobe;
	register struct	symtab 	**hp;
	register char 		*from;
	register char		*to;
	register	int	len;
	register	int	nprobes;
	static	struct	hashdallop *hdallop;
	static	struct	symtab	**emptyslot;
	static 	struct	hashdallop *emptyhd;
	static	struct	symtab	**hp_ub;

	emptyslot = 0;
	for (nprobes = 0, from = yytext;
	     *from;
	     nprobes <<= 2, nprobes += *from++)
		continue;
	nprobes += from[-1] << 5;
	nprobes %= NHASH;
	if (nprobes < 0)
		nprobes += NHASH;

	initialprobe = nprobes;
	for (hdallop = htab; hdallop != 0; hdallop = hdallop->h_next){
		for (hp = &(hdallop->h_htab[initialprobe]),
				nprobes = 1,
				hp_ub = &(hdallop->h_htab[NHASH]);
		     (*hp) && (nprobes < NHASH);
				hp += nprobes,
				hp -= (hp >= hp_ub) ? NHASH:0,
				nprobes += 2)
		{
			from = yytext;
			to = FETCHNAME(*hp);
			while (*from && *to)
				if (*from++ != *to++)
					goto nextprobe;
			if (*to == *from)	/*assert both are == 0*/
				return(hp);
		nextprobe: ;
		}
		if (*hp == 0 && emptyslot == 0 &&
		    hdallop->h_nused < HASHCLOGGED) {
			emptyslot = hp;
			emptyhd = hdallop;
		}
	}
	if (emptyslot == 0) {
		htaballoc();
		hdallop = htab->h_next;		/* aren't we smart! */
		hp = &hdallop->h_htab[initialprobe];
	} else {
		hdallop = emptyhd;
		hp = emptyslot;
	}
	if (instflg) {
		*hp = symalloc();
		hdallop->h_nused++;
		for (from = yytext, len = 0; *from++; len++)
			continue;
		(*hp)->s_name = (char *)savestr(yytext, len + 1, STR_BOTH);
	}
	return(hp);
}	/*end of lookup*/
/*
 *	save a string str with len in the places indicated by place
 */
struct strdesc *savestr(str, len, place)
	char	*str;
	int	len;
	int	place;
{
	reg	struct	strdesc	*res;
		int	tlen;
	/*
	 *	Compute the total length of the record to live in core
	 */
	tlen = sizeof(struct strdesc) - sizeof(res->sd_string);
	if (place & STR_CORE)
		tlen += len;
	/*
	 *	See if there is enough space for the record,
	 *	and allocate the record.
	 */
	if (tlen >= (STRPOOLDALLOP - strplhead->str_nalloc))
		strpoolalloc();
	res = (struct strdesc *)(strplhead->str_names + strplhead->str_nalloc);
	/*
	 *	Save the string information that is always present
	 */
	res->sd_stroff = strfilepos;
	res->sd_strlen = len;
	res->sd_place = place;
	/*
	 *	Now, save the string itself.  If str is null, then
	 *	the characters have already been dumped to the file
	 */
	if ((place & STR_CORE) && str)
		movestr(res[0].sd_string, str, len);
	if (place & STR_FILE){
		if (str){
			fwrite(str, 1, len, strfile);
		}
		strfilepos += len;
	}
	/*
	 *	Adjust the in core string pool size
	 */
	strplhead->str_nalloc += tlen;
	return(res);
}
/*
 *	The relocation information is saved internally in an array of
 *	lists of relocation buffers.  The relocation buffers are
 *	exactly the same size as a token buffer; if we use VM for the
 *	temporary file we reclaim this storage, otherwise we create
 *	them by mallocing.
 */
#define	RELBUFLG	TOKBUFLG
#define	NRELOC		((TOKBUFLG - \
			  (sizeof (int) + sizeof (struct relbufdesc *)) \
			) / (sizeof (struct relocation_info)))

struct	relbufdesc{
	int	rel_count;
	struct	relbufdesc	*rel_next;
	struct	relocation_info	rel_reloc[NRELOC];
};
extern	struct	relbufdesc	*tok_free;
#define	rel_free tok_free
static	struct	relbufdesc	*rel_temp;
struct	relocation_info r_can_1PC;
struct	relocation_info	r_can_0PC;

initoutrel()
{
	r_can_0PC.r_address = 0;
	r_can_0PC.r_symbolnum = 0;
	r_can_0PC.r_pcrel = 0;
	r_can_0PC.r_length = 0;
	r_can_0PC.r_extern = 0;

	r_can_1PC = r_can_0PC;
	r_can_1PC.r_pcrel = 1;
}

outrel(xp, reloc_how)
	register	struct	exp	*xp;
	int		reloc_how;	/* TYPB..TYPH + (possibly)RELOC_PCREL */
{
	struct		relocation_info	reloc;
	register	int	x_type_mask;	
			int	pcrel;

	x_type_mask = xp->e_xtype & ~XFORW;
	pcrel = reloc_how & RELOC_PCREL;
	reloc_how &= ~RELOC_PCREL;
	
	if (bitoff&07)
		yyerror("Padding error");
	if (x_type_mask == XUNDEF)
		yyerror("Undefined reference");

	if ( (x_type_mask != XABS) || pcrel ) {
		if (ty_NORELOC[reloc_how])
			yyerror("Illegal Relocation of floating or large int number.");
		reloc = pcrel ? r_can_1PC : r_can_0PC;
		reloc.r_address = dotp->e_xvalue -
		    ( (dotp < &usedot[NLOC] || readonlydata) ? 0 : datbase );
		reloc.r_length = ty_nlg[reloc_how];
		switch(x_type_mask){
			case XXTRN | XUNDEF:
				reloc.r_symbolnum = xp->e_xname->s_index;
				reloc.r_extern = 1;
				break;
			default:
				if (readonlydata && (x_type_mask&~XXTRN) == XDATA)
					x_type_mask = XTEXT | (x_type_mask&XXTRN);
				reloc.r_symbolnum = x_type_mask;
				break;
		}
		if ( (relfil == 0) || (relfil->rel_count >= NRELOC) ){
			if (rel_free){
				rel_temp = rel_free;
				rel_free = rel_temp->rel_next;
			} else {
				rel_temp = (struct relbufdesc *)
					Calloc(1,sizeof (struct relbufdesc));
			}
			rel_temp->rel_count = 0;
			rel_temp->rel_next = relfil;
			relfil = rusefile[dotp - &usedot[0]] = rel_temp;
		}
		relfil->rel_reloc[relfil->rel_count++] = reloc;
	}
	/*
	 *	write the unrelocated value to the text file
	 */
	dotp->e_xvalue += ty_nbyte[reloc_how];
	if (pcrel)
		xp->e_xvalue -= dotp->e_xvalue;
	switch(reloc_how){
	case TYPO:
	case TYPQ:

	case TYPF:
	case TYPD:
	case TYPG:
	case TYPH:
		bignumwrite(xp->e_number, reloc_how);
		break;

	default:
		bwrite((char *)&(xp->e_xvalue), ty_nbyte[reloc_how], txtfil);
		break;
	}
}
/*
 *	Flush out all of the relocation information.
 *	Note that the individual lists of buffers are in
 *	reverse order, so we must reverse them
 */
off_t closeoutrel(relocfile)
	BFILE	*relocfile;
{
	int	locindex;
	u_long	Closeoutrel();

	trsize = 0;
	for (locindex = 0; locindex < NLOC; locindex++){
		trsize += Closeoutrel(rusefile[locindex], relocfile);
	}
	drsize = 0;
	for (locindex = 0; locindex < NLOC; locindex++){
		drsize += Closeoutrel(rusefile[NLOC + locindex], relocfile);
	}
	return(trsize + drsize);
}

u_long Closeoutrel(relfil, relocfile)
	struct	relbufdesc	*relfil;
	BFILE	*relocfile;
{
	u_long	tail;
	if (relfil == 0)
		return(0L);
	tail = Closeoutrel(relfil->rel_next, relocfile);
	bwrite((char *)&relfil->rel_reloc[0],
		relfil->rel_count * sizeof (struct relocation_info),
		relocfile);
	return(tail + relfil->rel_count * sizeof (struct relocation_info));
}

#define NOUTSYMS (nsyms - njxxx - nforgotten - (savelabels ? 0 : nlabels))
int sizesymtab()
{
	return (sizeof (struct nlist) * NOUTSYMS);
}
/*
 *	Write out n symbols to file f, beginning at p
 *	ignoring symbols that are obsolete, jxxx instructions, and
 *	possibly, labels
 */
int symwrite(symfile)
	BFILE *symfile;
{
		int	symsout;		/*those actually written*/
		int	symsdesired = NOUTSYMS;
	reg	struct	symtab *sp, *ub;
		char	*name;			/* temp to save the name */
		int	totalstr;
	/*
	 *	We use sp->s_index to hold the length of the
	 *	name; it isn't used for anything else
	 */
	register	struct	allocbox	*allocwalk;

	symsout = 0;
	totalstr = sizeof(totalstr);
	DECLITERATE(allocwalk, sp, ub) {
		if (sp->s_tag >= IGNOREBOUND) 
			continue;
		if (ISLABEL(sp))
			continue;
		symsout++;
		name = sp->s_name;		/* save pointer */
		/*
		 *	the length of the symbol table string
		 *	always includes the trailing null;
		 *	blast the pointer to its a.out value.
		 */
		if (sp->s_name && (sp->s_index = STRLEN(sp))){
			sp->s_nmx = totalstr;
			totalstr += sp->s_index;
		} else {
			sp->s_nmx = 0;
		}
		if (sp->s_ptype != 0)
			sp->s_type = sp->s_ptype;
		else
			sp->s_type = (sp->s_type & (~XFORW));
		if (readonlydata && (sp->s_type&~N_EXT) == N_DATA)
			sp->s_type = N_TEXT | (sp->s_type & N_EXT);
		bwrite((char *)&sp->s_nm, sizeof (struct nlist), symfile);
		sp->s_name = name;		/* restore pointer */
	}
	if (symsout != symsdesired)
		yyerror("INTERNAL ERROR: Wrote %d symbols, wanted to write %d symbols\n",
			symsout, symsdesired);
	/*
	 *	Construct the string pool from the symbols that were written,
	 *	possibly fetching from the string file if the string
	 *	is not core resident.
	 */
	bwrite(&totalstr, sizeof(totalstr), symfile);
	symsout = 0;
	DECLITERATE(allocwalk, sp, ub) {
		if (sp->s_tag >= IGNOREBOUND) 
			continue;
		if (ISLABEL(sp))
			continue;
		symsout++;
		if (STRLEN(sp) > 0){
		 if (STRPLACE(sp) & STR_CORE){
			bwrite(FETCHNAME(sp), STRLEN(sp), symfile);
		 } else if (STRPLACE(sp) & STR_FILE){
			char	rbuf[2048];
			int	left, nread;
			fseek(strfile, STROFF(sp), 0);
			for (left = STRLEN(sp); left > 0; left -= nread){
				nread = fread(rbuf, sizeof(char),
					min(sizeof(rbuf), left), strfile);
				if (nread == 0)
					break;
				bwrite(rbuf, nread, symfile);
			}
		 }
		}
	}
	if (symsout != symsdesired)
		yyerror("INTERNAL ERROR: Wrote %d strings, wanted %d\n",
			symsout, symsdesired);
}