trees.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 1,611 行 · 第 1/3 页

#ifndef	lint
static char *sccsid ="@(#)trees.c	1.1 (decvax!reilly) 4/27/84";
#endif

/************************************************************************
 *
 *			Modification History
 *
 *	Stephen Reilly, 13-Feb-84
 * 002- Fix a coding bug from ( 001 ).  The problem was I thought asgop
 *	only was true for assign type operations.  Not true the RETURN
 *	CAST are considered assign typea which causes conversion problems.
 *
 *	Stephen Reilly, 20-Jan-84
 * 001- Fix the problem with ( int op= real ). The bug was that the
 *	real was converted to the int rather than the int being 
 *	converted to real.  
 *
 ***********************************************************************/

/************************************************************************
 *									*
 *			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.	*
 *									*
 ************************************************************************/

# include "mfile1"

	    /* corrections when in violation of lint */

/*	some special actions, used in finding the type of nodes */
# define NCVT 01
# define PUN 02
# define TYPL 04
# define TYPR 010
# define TYMATCH 040
# define LVAL 0100
# define CVTO 0200
# define CVTL 0400
# define CVTR 01000
# define PTMATCH 02000
# define OTHER 04000
# define NCVTR 010000

/* node conventions:

	NAME:	rval>0 is stab index for external
		rval<0 is -inlabel number
		lval is offset in bits
	ICON:	lval has the value
		rval has the STAB index, or - label number,
			if a name whose address is in the constant
		rval = NONAME means no name
	REG:	rval is reg. identification cookie

	*/

int bdebug = 0;
extern ddebug;

NODE *
buildtree( o, l, r ) register NODE *l, *r; {
	register NODE *p, *q;
	register actions;
	register opty;
	register struct symtab *sp;
	register NODE *lr, *ll;
	int i;
	extern int eprint();

# ifndef BUG1
	if( bdebug ) printf( "buildtree( %s, %o, %o )\n", opst[o], l, r );
# endif
	opty = optype(o);

	/* check for constants */

	if( opty == UTYPE && l->in.op == ICON ){

		switch( o ){

		case NOT:
			if( hflag ) werror( "constant argument to NOT" );
		case UNARY MINUS:
		case COMPL:
			if( conval( l, o, l ) ) return(l);
			break;

			}
		}

	else if( o==UNARY MINUS && l->in.op==FCON ){
		l->fpn.dval = -l->fpn.dval;
		return(l);
		}

	else if( o==QUEST && l->in.op==ICON ) {
		l->in.op = FREE;
		r->in.op = FREE;
		if( l->tn.lval ){
			tfree( r->in.right );
			return( r->in.left );
			}
		else {
			tfree( r->in.left );
			return( r->in.right );
			}
		}

	else if( (o==ANDAND || o==OROR) && (l->in.op==ICON||r->in.op==ICON) ) goto ccwarn;

	else if( opty == BITYPE && l->in.op == ICON && r->in.op == ICON ){

		switch( o ){

		case ULT:
		case UGT:
		case ULE:
		case UGE:
		case LT:
		case GT:
		case LE:
		case GE:
		case EQ:
		case NE:
		case ANDAND:
		case OROR:
		case CBRANCH:

		ccwarn:
			if( hflag ) werror( "constant in conditional context" );

		case PLUS:
		case MINUS:
		case MUL:
		case DIV:
		case MOD:
		case AND:
		case OR:
		case ER:
		case LS:
		case RS:
			if( conval( l, o, r ) ) {
				r->in.op = FREE;
				return(l);
				}
			break;
			}
		}

	else if( opty == BITYPE && (l->in.op==FCON||l->in.op==ICON) &&
		(r->in.op==FCON||r->in.op==ICON) ){
		switch(o){
		case PLUS:
		case MINUS:
		case MUL:
		case DIV:
			if( l->in.op == ICON ){
				l->fpn.dval = l->tn.lval;
				}
			if( r->in.op == ICON ){
				r->fpn.dval = r->tn.lval;
				}
			l->in.op = FCON;
			l->in.type = l->fn.csiz = DOUBLE;
			r->in.op = FREE;
			switch(o){
			case PLUS:
				l->fpn.dval += r->fpn.dval;
				return(l);
			case MINUS:
				l->fpn.dval -= r->fpn.dval;
				return(l);
			case MUL:
				l->fpn.dval *= r->fpn.dval;
				return(l);
			case DIV:
				if( r->fpn.dval == 0 ) uerror( "division by 0." );
				else l->fpn.dval /= r->fpn.dval;
				return(l);
				}
			}
		}

	/* its real; we must make a new node */

	p = block( o, l, r, INT, 0, INT );

	actions = opact(p);

	if( actions&LVAL ){ /* check left descendent */
		if( notlval(p->in.left) ) {
			uerror( "illegal lhs of assignment operator" );
			}
		}

	if( actions & NCVTR ){
		p->in.left = pconvert( p->in.left );
		}
	else if( !(actions & NCVT ) ){
		switch( opty ){

		case BITYPE:
			p->in.right = pconvert( p->in.right );
		case UTYPE:
			p->in.left = pconvert( p->in.left );

			}
		}

	if( (actions&PUN) && (o!=CAST||cflag) ){
		chkpun(p);
		}

	if( actions & (TYPL|TYPR) ){

		q = (actions&TYPL) ? p->in.left : p->in.right;

		p->in.type = q->in.type;
		p->fn.cdim = q->fn.cdim;
		p->fn.csiz = q->fn.csiz;
		}

	if( actions & CVTL ) p = convert( p, CVTL );
	if( actions & CVTR ) p = convert( p, CVTR );
	if( actions & TYMATCH ) p = tymatch(p);
	if( actions & PTMATCH ) p = ptmatch(p);

	if( actions & OTHER ){
		l = p->in.left;
		r = p->in.right;

		switch(o){

		case NAME:
			sp = &stab[idname];
			if( sp->stype == UNDEF ){
#ifndef FLEXNAMES
				uerror( "%.8s undefined", sp->sname );
#else
				uerror( "%s undefined", sp->sname );
#endif
				/* make p look reasonable */
				p->in.type = p->fn.cdim = p->fn.csiz = INT;
				p->tn.rval = idname;
				p->tn.lval = 0;
				defid( p, SNULL );
				break;
				}
			p->in.type = sp->stype;
			p->fn.cdim = sp->dimoff;
			p->fn.csiz = sp->sizoff;
			p->tn.lval = 0;
			p->tn.rval = idname;
			/* special case: MOETY is really an ICON... */
			if( p->in.type == MOETY ){
				p->tn.rval = NONAME;
				p->tn.lval = sp->offset;
				p->fn.cdim = 0;
				p->in.type = ENUMTY;
				p->in.op = ICON;
				}
			break;

		case ICON:
			p->in.type = INT;
			p->fn.cdim = 0;
			p->fn.csiz = INT;
			break;

		case STRING:
			p->in.op = NAME;
			p->in.type = CHAR+ARY;
			p->tn.lval = 0;
			p->tn.rval = NOLAB;
			p->fn.cdim = curdim;
			p->fn.csiz = CHAR;
			break;

		case FCON:
			p->tn.lval = 0;
			p->tn.rval = 0;
			p->in.type = DOUBLE;
			p->fn.cdim = 0;
			p->fn.csiz = DOUBLE;
			break;

		case STREF:
			/* p->x turned into *(p+offset) */
			/* rhs must be a name; check correctness */

			i = r->tn.rval;
			if( i<0 || ((sp= &stab[i])->sclass != MOS && sp->sclass != MOU && !(sp->sclass&FIELD)) ){
				uerror( "member of structure or union required" );
				}else
			/* if this name is non-unique, find right one */
			if( stab[i].sflags & SNONUNIQ &&
				(l->in.type==PTR+STRTY || l->in.type == PTR+UNIONTY) &&
				(l->fn.csiz +1) >= 0 ){
				/* nonunique name && structure defined */
				char * memnam, * tabnam;
				register k;
				int j;
				int memi;
				j=dimtab[l->fn.csiz+1];
				for( ; (memi=dimtab[j]) >= 0; ++j ){
					tabnam = stab[memi].sname;
					memnam = stab[i].sname;
# ifndef BUG1
					if( ddebug>1 ){
#ifndef FLEXNAMES
						printf("member %.8s==%.8s?\n",
#else
						printf("member %s==%s?\n",
#endif
							memnam, tabnam);
						}
# endif
					if( stab[memi].sflags & SNONUNIQ ){
#ifndef FLEXNAMES
						for( k=0; k<NCHNAM; ++k ){
							if(*memnam++!=*tabnam)
								goto next;
							if(!*tabnam++) break;
							}
#else
						if (memnam != tabnam)
							goto next;
#endif
						r->tn.rval = i = memi;
						break;
						}
					next: continue;
					}
				if( memi < 0 )
#ifndef FLEXNAMES
					uerror("illegal member use: %.8s",
#else
					uerror("illegal member use: %s",
#endif
						stab[i].sname);
				}
			else {
				register j;
				if( l->in.type != PTR+STRTY && l->in.type != PTR+UNIONTY ){
					if( stab[i].sflags & SNONUNIQ ){
						uerror( "nonunique name demands struct/union or struct/union pointer" );
						}
					else werror( "struct/union or struct/union pointer required" );
					}
				else if( (j=l->fn.csiz+1)<0 ) cerror( "undefined structure or union" );
				else if( !chkstr( i, dimtab[j], DECREF(l->in.type) ) ){
#ifndef FLEXNAMES
					werror( "illegal member use: %.8s", stab[i].sname );
#else
					werror( "illegal member use: %s", stab[i].sname );
#endif
					}
				}

			p = stref( p );
			break;

		case UNARY MUL:
			if( l->in.op == UNARY AND ){
				p->in.op = l->in.op = FREE;
				p = l->in.left;
				}
			if( !ISPTR(l->in.type))uerror("illegal indirection");
			p->in.type = DECREF(l->in.type);
			p->fn.cdim = l->fn.cdim;
			p->fn.csiz = l->fn.csiz;
			break;

		case UNARY AND:
			switch( l->in.op ){

			case UNARY MUL:
				p->in.op = l->in.op = FREE;
				p = l->in.left;
			case NAME:
				p->in.type = INCREF( l->in.type );
				p->fn.cdim = l->fn.cdim;
				p->fn.csiz = l->fn.csiz;
				break;

			case COMOP:
				lr = buildtree( UNARY AND, l->in.right, NIL );
				p->in.op = l->in.op = FREE;
				p = buildtree( COMOP, l->in.left, lr );
				break;

			case QUEST:
				lr = buildtree( UNARY AND, l->in.right->in.right, NIL );
				ll = buildtree( UNARY AND, l->in.right->in.left, NIL );
				p->in.op = l->in.op = l->in.right->in.op = FREE;
				p = buildtree( QUEST, l->in.left, buildtree( COLON, ll, lr ) );
				break;

# ifdef ADDROREG
			case OREG:
				/* OREG was built in clocal()
				 * for an auto or formal parameter
				 * now its address is being taken
				 * local code must unwind it
				 * back to PLUS/MINUS REG ICON
				 * according to local conventions
				 */
				{
				extern NODE * addroreg();
				p->in.op = FREE;
				p = addroreg( l );
				}
				break;

# endif
			default:
				uerror( "unacceptable operand of &" );
				break;
				}
			break;

		case LS:
		case RS:
		case ASG LS:
		case ASG RS:
			if(tsize(p->in.right->in.type, p->in.right->fn.cdim, p->in.right->fn.csiz) > SZINT)
				p->in.right = makety(p->in.right, INT, 0, INT );
			break;

		case RETURN:
		case ASSIGN:
		case CAST:
			/* structure assignment */
			/* take the addresses of the two sides; then make an
			/* operator using STASG and
			/* the addresses of left and right */

			{
				register TWORD t;
				register d, s;

				if( l->fn.csiz != r->fn.csiz ) uerror( "assignment of different structures" );

				r = buildtree( UNARY AND, r, NIL );
				t = r->in.type;
				d = r->fn.cdim;
				s = r->fn.csiz;

				l = block( STASG, l, r, t, d, s );

				if( o == RETURN ){
					p->in.op = FREE;
					p = l;
					break;
					}

				p->in.op = UNARY MUL;
				p->in.left = l;
				p->in.right = NIL;
				break;
				}
		case COLON:
			/* structure colon */

			if( l->fn.csiz != r->fn.csiz ) uerror( "type clash in conditional" );
			break;

		case CALL:
			p->in.right = r = strargs( p->in.right );
		case UNARY CALL:
			if( !ISPTR(l->in.type)) uerror("illegal function");
			p->in.type = DECREF(l->in.type);
			if( !ISFTN(p->in.type)) uerror("illegal function");
			p->in.type = DECREF( p->in.type );
			p->fn.cdim = l->fn.cdim;
			p->fn.csiz = l->fn.csiz;
			if( l->in.op == UNARY AND && l->in.left->in.op == NAME &&
				l->in.left->tn.rval >= 0 && l->in.left->tn.rval != NONAME &&
				( (i=stab[l->in.left->tn.rval].sclass) == FORTRAN || i==UFORTRAN ) ){
				p->in.op += (FORTCALL-CALL);
				}
			if( p->in.type == STRTY || p->in.type == UNIONTY ){
				/* function returning structure */
				/*  make function really return ptr to str., with * */

				p->in.op += STCALL-CALL;
				p->in.type = INCREF( p->in.type );
				p = buildtree( UNARY MUL, p, NIL );

				}
			break;

		default:
			cerror( "other code %d", o );
			}

		}

	if( actions & CVTO ) p = oconvert(p);
	p = clocal(p);

# ifndef BUG1
	if( bdebug ) fwalk( p, eprint, 0 );
# endif

	return(p);

	}

NODE *
strargs( p ) register NODE *p;  { /* rewrite structure flavored arguments */

	if( p->in.op == CM ){