assyms.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

/*#@(#)assyms.c	4.3	Ultrix	9/4/90*/

/************************************************************************
 *									*
 *			Copyright (c) 1984 by				*
 *		Digital Equipment Corporation, Maynard, MA		*
 *			All rights reserved.				*
 *									*
 *   This software is furnished under a license and may be used and	*
 *   copied  only  in accordance with the terms of such license and	*
 *   with the  inclusion  of  the  above  copyright  notice.   This	*
 *   software  or  any  other copies thereof may not be provided or	*
 *   otherwise made available to any other person.  No title to and	*
 *   ownership of the software is hereby transferred.			*
 *									*
 *   This software is  derived  from  software  received  from  the	*
 *   University    of   California,   Berkeley,   and   from   Bell	*
 *   Laboratories.  Use, duplication, or disclosure is  subject  to	*
 *   restrictions  under  license  agreements  with  University  of	*
 *   California and with AT&T.						*
 *									*
 *   The information in this software is subject to change  without	*
 *   notice  and should not be construed as a commitment by Digital	*
 *   Equipment Corporation.						*
 *									*
 *   Digital assumes no responsibility for the use  or  reliability	*
 *   of its software on equipment which is not supplied by Digital.	*
 *									*
 ************************************************************************/

/************************************************************************
 *									*
 *			Modification History				*
 *									*
 *
 * 002  Tanya Klinchina, 20-Nov-1989
 *      Added support for vector instructions.
 *									*
 *	001 - Modified stabfix() to work with changes made in asparse.c *
 *	      (don't have to shift/mask the offset back out of		*
 *	      n_desc and n_other fields).  Takes advantage of new	*
 *	      stabtype FORWARDSTAB.					*
 *	      Also modified sortsymtab():  no longer assign value field *
 *	      of a forward-referencing stab for sorting; this is	*
 *	      unnecessary, and munges the s_value field of the stab	*
 *	      which might be used to hold an offset later needed in	*
 *	      stabfix().						*
 *	      (Victoria Holt, May 7, 1985)				*
 *									*
 ************************************************************************/

/*
 *	Copyright (c) 1982 Regents of the University of California
 */
#ifndef lint
static char sccsid[] = "@(#)assyms.c 4.14 8/11/83";
#endif /* not lint */

#include <stdio.h>
#include <ctype.h>
#include "as.h"
#include "asscan.h"
#include "assyms.h"

/*
 *	Managers for chunks of symbols allocated from calloc()
 *	We maintain a linked list of such chunks.
 *
 */
struct	allocbox	*allochead;	/*head of chunk list*/
struct	allocbox	*alloctail;	/*tail*/
struct	allocbox	*newbox;	/*for creating a new chunk*/
struct	symtab		*nextsym;	/*next symbol free*/
int			symsleft;	/*slots left in current chunk*/

struct	symtab		**symptrs;
struct	symtab		**symdelim[NLOC + NLOC +1];
struct	symtab		**symptrub;
/*
 *	Managers for the dynamically extendable hash table
 */
struct	hashdallop	*htab;

Iptr	*itab[NINST];	/*maps opcodes to instructions*/
/*
 *	Counts what went into the symbol table, so that the
 *	size of the symbol table can be computed.
 */
int	nsyms;		/* total number in the symbol table */
int	njxxx;		/* number of jxxx entrys */
int	nforgotten;	/* number of symbols erroneously entered */
int	nlabels;	/* number of label entries */

/*
 *	Managers of the symbol literal storage.
 */
struct	strpool		*strplhead = 0;

symtabinit()
{
	allochead = 0;
	alloctail = 0;
	nextsym = 0;
	symsleft = 0;
	strpoolalloc();		/* get the first strpool storage area */
	htab = 0;
	htaballoc();		/* get the first part of the hash table */
}

/*
 *	Install all known instructions in the symbol table
 */
syminstall()
{
	register	Iptr	ip;
	register	struct	symtab	**hp;
	register	char	*p1, *p2;
	register	int	i;

	for (i = 0; i < NINST; i++)
		itab[i] = (Iptr*)BADPOINT;

	for (ip = (Iptr)instab; FETCHNAME(ip)[0]; ip++) {
		p1 = FETCHNAME(ip);
		p2 = yytext;
		while (*p2++ = *p1++);
		hp = lookup(0);		/* 0 => don't install this*/
		if (*hp==NULL) {
			*hp = (struct symtab *)ip;
			if (   (ip->s_tag!=INSTn)
			    && (ip->s_tag!=INST0)
			    && (ip->s_tag!=VINSTn)
			    && (ip->s_tag!=VINST0)
			    && (ip->s_tag!=0))
				continue; /* was pseudo-op */
			if (itab[ip->i_eopcode] == (Iptr*)BADPOINT){
				itab[ip->i_eopcode] =
					(Iptr*)ClearCalloc(256, sizeof(Iptr));
				for (i = 0; i < 256; i++)
					itab[ip->i_eopcode][i] =
						(Iptr)BADPOINT;
			}
			itab[ip->i_eopcode][ip->i_popcode] = ip;
		}
	}
}	/*end of syminstall*/

#define ISLABEL(sp) \
	(   (!savelabels) \
	 && (sp->s_tag == LABELID) \
	 && (STRPLACE(sp) & STR_CORE) \
	 && (FETCHNAME(sp)[0] == 'L'))
/*
 *	Assign final values to symbols,
 *	and overwrite the index field with its relative position in
 *	the symbol table we give to the loader.
 */
extern struct exec hdr;

freezesymtab()
{
	register	struct	symtab	*sp;
				long	bs;
	register	int	relpos = 0;
	register	struct	symtab		*ubsp;
	register	struct	allocbox	*allocwalk;

	DECLITERATE(allocwalk, sp, ubsp)
	{
		if (sp->s_tag >= IGNOREBOUND)
			continue; 		/*totally ignore jxxx entries */
		/*
		 *	Ignore stabs, but give them a symbol table index
		 */
		if (sp->s_type & STABFLAG)
			goto assignindex;
		if ((sp->s_type&XTYPE)==XUNDEF)
			sp->s_type = XXTRN+XUNDEF;
		else if ((sp->s_type&XTYPE)==XDATA)
			sp->s_value += usedot[sp->s_index].e_xvalue;
		else if ((sp->s_type&XTYPE)==XTEXT)
			sp->s_value += usedot[sp->s_index].e_xvalue;
		else if ((sp->s_type&XTYPE)==XBSS) {
			bs = sp->s_value;
			sp->s_value = hdr.a_bss + datbase;
			hdr.a_bss += bs;
		}
	   assignindex:
		if (!ISLABEL(sp))
			sp->s_index = relpos++;
	}
}

/*
 *	For all of the stabs that had their final value undefined
 *	at pass 1, we now assign a final value.
 *	We have already given stab entrys a initial approximation
 *	when we constsructed the sorted symbol table.
 *	Iteration order doesn't matter.
 */

stabfix()
{
	register struct symtab *sp, **cosp;
	register struct symtab *p;
	
	SYMITERATE(cosp, sp) {
		if(sp->s_ptype && (sp->s_type & STABFLAG)) {	
			p = sp->s_dest;	
			sp->s_index = p->s_index;
			sp->s_type = p->s_type;
			if (sp->s_tag == FORWARDSTAB) {
			    sp->s_value += p->s_value;
			} else {
			    sp->s_value = p->s_value;
			}
		}
	}
}

char *Calloc(number, size)
	int	number, size;
{
	register	char *newstuff;
	char	*sbrk();
	newstuff = sbrk(number*size);
	if ((int)newstuff == -1){
		yyerror("Ran out of Memory");
		delexit();
	}
	return(newstuff);
}

char *ClearCalloc(number, size)
	int	number, size;
{
	register	char	*newstuff;		/* r11 */
	register	int	length = number * size;	/* r10 */
#ifdef lint
	length = length;
#endif /* length */
	newstuff = Calloc(number, size);
	asm("movc5 $0, (r0), $0, r10, (r11)");
	return(newstuff);
}

struct symtab *symalloc()
{
	if (symsleft == 0){
		newbox = (struct allocbox *)ClearCalloc(1,ALLOCQTY);
		symsleft = SYMDALLOP;
		nextsym = &newbox->symslots[0];
		if (alloctail == 0){
			allochead = alloctail = newbox;
		} else {
			alloctail->nextalloc = newbox;
			alloctail = newbox;
		}
	}
	--symsleft;
	++nsyms;
	return(nextsym++);
}

strpoolalloc()
{
	register	struct	strpool	*new;

	new = (struct strpool *)Calloc(1, sizeof (struct strpool));
	new->str_nalloc = 0;
	new->str_next = strplhead;
	strplhead = new;
}

symcmp(Pptr, Qptr)
	struct symtab **Pptr, **Qptr;
{
	register struct symtab *p = *Pptr;
	register struct symtab *q = *Qptr;
	if (p->s_index < q->s_index)
		return(-1);
	if (p->s_index > q->s_index)
		return(1);
	if (p->s_value < q->s_value)
		return(-1);
	if (p->s_value > q->s_value)
		return(1);
	/*
	 *	Force jxxx entries to virtually preceed labels defined
	 *	to follow the jxxxx instruction, so that bumping the
	 *	jxxx instruction correctly fixes up the following labels
	 */
	if (p->s_tag >= IGNOREBOUND)	/*p points to a jxxx*/
		return(-1);		
	if (q->s_tag >= IGNOREBOUND)
		return(1);
	/*
	 *	both are now just plain labels; the relative order doesn't
	 *	matter.  Both can't be jxxxes, as they would have different
	 *	values.
	 */
	return(0);			
}	/*end of symcmp*/

/*
 *	We construct the auxiliary table of pointers, symptrs and
 *	symdelim.
 *	Also assign a segment (s_index) to stabs that previously 
 *	addressed a forward reference.
 */

sortsymtab()
{
	register	struct	symtab	*sp;
	register	struct	symtab	**cowalk;
	register	struct	allocbox	*allocwalk;
			struct	symtab	*ubsp;
				int	segno;
				int	slotno;
				int	symsin;	/*number put into symptrs*/

	symptrs =  (struct symtab **)Calloc(nsyms + 2, sizeof *symptrs);
	/*
	 *	Allocate one word at the beginning of the symptr array
	 *	so that backwards scans through the symptr array will
	 *	work correctly while scanning through the zeroth segment
	 */
	*symptrs++ = 0;
	cowalk = symptrs;
	symsin = 0;
	DECLITERATE(allocwalk, sp, ubsp) {
		if (sp->s_ptype && (sp->s_type &STABFLAG)){
			sp->s_index = sp->s_dest->s_index;

			/* No longer assign the address; is not needed */
			/* because true value will be assigned in */
			/* stabfix().  Sorting of stabs need only be */
			/* done by index for this reason (jxxxfix will */
			/* not have any effect. */
			/* sp->s_value = sp->dest->s_value; */
		}
		if (symsin >= nsyms)
			yyerror("INTERNAL ERROR: overfilled symbol table indirection table");
		*cowalk++ = sp;
		symsin++;
	}
	if (symsin != nsyms)
		yyerror("INTERNAL ERROR: installed %d syms, should have installed %d",
			symsin, nsyms);
	symptrub = &symptrs[nsyms ];
	qsort(symptrs, nsyms, sizeof *symptrs, symcmp);
	symdelim[0] = symptrs;
	for (cowalk = symptrs, sp = *cowalk, segno = 0, slotno = 1;
	     segno < NLOC + NLOC;
	     segno++, slotno++){
		for (; sp && sp->s_index == segno; sp = *++cowalk);
		symdelim[slotno] = cowalk;	/*forms the ub delimeter*/
	}
}	/*end of sortsymtab*/

#ifdef DEBUG
dumpsymtab()
{
	register	int	segno;
	register	struct symtab *sp, **cosp, *ub;
	char		*tagstring();

	printf("Symbol Table dump:\n");
	for (segno = 0; segno < NLOC + NLOC; segno++){
		printf("Segment number: %d\n", segno);
		SEGITERATE(segno, 0, 0, cosp, sp, ub, ++){
			printf("\tSeg: %d \"%s\" value: %d index: %d tag %s\n",
				segno, FETCHNAME(sp),
				sp->s_value, sp->s_index,
				tagstring(sp->s_tag));
			printf("\t\ttype: %d jxbump %d jxfear: %d\n",
				sp->s_type, sp->s_jxbump, sp->s_jxfear);
		}
		printf("\n\n");
	}
}

static	char tagbuff[4];

char *tagstring(tag)
	unsigned	char	tag;
{
	switch(tag){
		case JXACTIVE:		return("active");
		case JXNOTYET:		return("notyet");