trees.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

				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);

	}

/* vdp012 report floating point exception.  
 * If fpe_count is not less then 0 then 
 * the floating point signal occured when 
 * we were combining constants in buildtree
 * (see call to setjmp)
 */
int fpe_count = -1;
jmp_buf gotfpe;

void
fpe() {
	if (fpe_count < 0)
		cerror("floating point exception");
	++fpe_count;
	longjmp(gotfpe, 1);
	}

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

	if( p->in.op == CM ){
		p->in.left = strargs( p->in.left );
		p->in.right = strargs( p->in.right );
		return( p );
		}

	/*RAP005
		Catch use of functions that don't return values used as
		arguements.
	*/
	if ((p->in.op==UNARY CALL || p->in.op==CALL ) && p->in.type==UNDEF)
		uerror("void or undef used in value required context");

	if( p->in.type == STRTY || p->in.type == UNIONTY ){
		p = block( STARG, p, NIL, p->in.type, p->fn.cdim, p->fn.csiz );
		p->in.left = buildtree( UNARY AND, p->in.left, NIL );
		p = clocal(p);
		}

       /* vdp Single	(e.g. 34.56f )  
 	* precision floating point constants are
 	* cast to double (to eliminate convert code).
 	*/

	else if( p->in.op == FCON )
		p = makety(p, DOUBLE, 0, 0);

	return( p );
	}


chkstr( i, j, type ) TWORD type; {
	/* is the MOS or MOU at stab[i] OK for strict reference by a ptr */
	/* i has been checked to contain a MOS or MOU */
	/* j is the index in dimtab of the members... */
	int k, kk;

	extern int ddebug;

# ifndef BUG1
#ifndef FLEXNAMES
	if( ddebug > 1 ) printf( "chkstr( %.8s(%d), %d )\n", stab[i].sname, i, j );
#else
	if( ddebug > 1 ) printf( "chkstr( %s(%d), %d )\n", stab[i].sname, i, j );
#endif
# endif
	if( (k = j) < 0 ) uerror( "undefined structure or union" );
	else {
		for( ; (kk = dimtab[k] ) >= 0; ++k ){
			if( kk >= SYMTSZ ){
				cerror( "gummy structure" );
				return(1);
				}
			if( kk == i ) return( 1 );
			switch( stab[kk].stype ){

			case STRTY:
			case UNIONTY:
				if( type == STRTY ) continue;  /* no recursive looking for strs */
				if( hflag && chkstr( i, dimtab[stab[kk].sizoff+1], stab[kk].stype ) ){
					if( stab[kk].sname[0] == '$' ) return(0);  /* $FAKE */
					werror(
#ifndef FLEXNAMES
					"illegal member use: perhaps %.8s.%.8s?",
#else
					"illegal member use: perhaps %s.%s?",
#endif
					stab[kk].sname, stab[i].sname );
					return(1);
					}
				}
			}
		}
	return( 0 );
	}

conval( p, o, q ) register NODE *p, *q; {
	/* apply the op o to the lval part of p; if binary, rhs is val */
	int i, u;
	CONSZ val;

	val = q->tn.lval;
	u = ISUNSIGNED(p->in.type) || ISUNSIGNED(q->in.type);
	if( u && (o==LE||o==LT||o==GE||o==GT)) o += (UGE-GE);

	if( p->tn.rval != NONAME && q->tn.rval != NONAME ) return(0);
	if( q->tn.rval != NONAME && o!=PLUS ) return(0);
	if( p->tn.rval != NONAME && o!=PLUS && o!=MINUS ) return(0);

	switch( o ){

	case PLUS:
		p->tn.lval += val;
		if( p->tn.rval == NONAME ){
			p->tn.rval = q->tn.rval;
			p->in.type = q->in.type;
			}
		break;
	case MINUS:
		p->tn.lval -= val;
		break;
	case MUL:
		p->tn.lval *= val;
		break;
	case DIV:
		if( val == 0 )
			uerror( "division by 0" );
		else if (u)
			p->tn.lval /= (unsigned)val;
		else
			p->tn.lval /= val;
		break;
	case MOD:
		if( val == 0 )
			uerror( "division by 0" );
		else if (u)
			p->tn.lval %= (unsigned)val;
		else
			p->tn.lval %= val;
		break;
	case AND:
		p->tn.lval &= val;
		break;
	case OR:
		p->tn.lval |= val;
		break;
	case ER:
		p->tn.lval ^=  val;
		break;
	case LS:
		i = val;
		if (u)
			p->tn.lval = (unsigned)p->tn.lval << i;
		else
			p->tn.lval = p->tn.lval << i;
		break;
	case RS:
		i = val;
		if (u)
			p->tn.lval = (unsigned)p->tn.lval >> i;
		else
			p->tn.lval = p->tn.lval >> i;
		break;

	case UNARY MINUS:
		p->tn.lval = - p->tn.lval;
		break;
	case COMPL:
		p->tn.lval = ~p->tn.lval;
		break;
	case NOT:
		p->tn.lval = !p->tn.lval;
		break;
	case LT:
		p->tn.lval = p->tn.lval < val;
		break;
	case LE:
		p->tn.lval = p->tn.lval <= val;
		break;
	case GT:
		p->tn.lval = p->tn.lval > val;
		break;
	case GE:
		p->tn.lval = p->tn.lval >= val;
		break;
	case ULT:
		p->tn.lval = (p->tn.lval-val)<0;
		break;
	case ULE:
		p->tn.lval = (p->tn.lval-val)<=0;
		break;
	case UGE:
		p->tn.lval = (p->tn.lval-val)>=0;
		break;
	case UGT:
		p->tn.lval = (p->tn.lval-val)>0;
		break;
	case EQ:
		p->tn.lval = p->tn.lval == val;
		break;
	case NE:
		p->tn.lval = p->tn.lval != val;
		break;
	default:
		return(0);
		}
	return(1);
	}

chkpun(p) register NODE *p; {

	/* checks p for the existance of a pun */

	/* this is called when the op of p is ASSIGN, RETURN, CAST, COLON, or relational */

	/* one case is when enumerations are used: this applies only to lint */
	/* in the other case, one operand is a pointer, the other integer type */
	/* we check that this integer is in fact a constant zero... */

	/* in the case of ASSIGN, any assignment of pointer to integer is illegal */
	/* this falls out, because the LHS is never 0 */

	register NODE *q;
	register t1, t2;
	register d1, d2;

	t1  = p->in.left->in.type;
	t2  = p->in.right->in.type;

	if( t1==ENUMTY || t2==ENUMTY ) { /* check for enumerations */
		if( logop( p->in.op ) && p->in.op != EQ && p->in.op != NE ) {
			uerror( "illegal comparison of enums" );
			return;
			}
		if( t1==ENUMTY && t2==ENUMTY && p->in.left->fn.csiz==p->in.right->fn.csiz ) return;
		werror( "enumeration type clash, operator %s", opst[p->in.op] );
		return;
		}

	if( ISPTR(t1) || ISARY(t1) ) q = p->in.right;
	else q = p->in.left;

	if( !ISPTR(q->in.type) && !ISARY(q->in.type) ){
		if( q->in.op != ICON || q->tn.lval != 0 ){
			werror( "illegal combination of pointer and integer, op %s",
				opst[p->in.op] );
			}
		}
	else {
		d1 = p->in.left->fn.cdim;
		d2 = p->in.right->fn.cdim;
		for( ;; ){
			if( t1 == t2 ) {;
				if( p->in.left->fn.csiz != p->in.right->fn.csiz ) {
					werror( "illegal structure pointer combination" );
					}
				return;
				}
			if( ISARY(t1) || ISPTR(t1) ){
				if( !ISARY(t2) && !ISPTR(t2) ) break;
				if( ISARY(t1) && ISARY(t2) && dimtab[d1] != dimtab[d2] ){
					werror( "illegal array size combination" );
					return;
					}
				if( ISARY(t1) ) ++d1;
				if( ISARY(t2) ) ++d2;
				}
			else break;
			t1 = DECREF(t1);
			t2 = DECREF(t2);
			}
		werror( "illegal pointer combination" );
		}

	}

NODE *
stref( p ) register NODE *p; {

	TWORD t;
	int d, s, dsc, align;
	OFFSZ off;
	register struct symtab *q;

	/* make p->x */
	/* this is also used to reference automatic variables */

	q = &stab[p->in.right->tn.rval];
	p->in.right->in.op = FREE;
	p->in.op = FREE;
	p = pconvert( p->in.left );

	/* make p look like ptr to x */

	if( !ISPTR(p->in.type)){
		p->in.type = PTR+UNIONTY;
		}

	t = INCREF( q->stype );
	d = q->dimoff;
	s = q->sizoff;

	p = makety( p, t, d, s );
 	p->in.typattr = INCATTR(q->stypattr);

	/* compute the offset to be added */

	off = q->offset;
	dsc = q->sclass;

	if( dsc & FIELD ) {  /* normalize offset */
		align = ALINT;
		s = INT;
		off = (off/align)*align;
		}
	if( off != 0 ) p = clocal( block( PLUS, p, offcon( off, t, d, s ), t, d, s ) );

	p = buildtree( UNARY MUL, p, NIL );

	/* if field, build field info */

	if( dsc & FIELD ){
		p = block( FLD, p, NIL, q->stype, 0, q->sizoff );
		p->tn.rval = PKFIELD( dsc&FLDSIZ, q->offset%align );
		}

	return( clocal(p) );
	}

notlval(p) register NODE *p; {

	/* return 0 if p an lvalue, 1 otherwise */

	again:

	switch( p->in.op ){

	case FLD:
		p = p->in.left;
		goto again;

	case UNARY MUL:
		/* fix the &(a=b) bug, given that a and b are structures */
		if( p->in.left->in.op == STASG ) return( 1 );
		/* and the f().a bug, given that f returns a structure */
		if( p->in.left->in.op == UNARY STCALL ||
		    p->in.left->in.op == STCALL ) return( 1 );
	case NAME:
	case OREG:
		if (ISARY(p->in.type) || ISFTN(p->in.type))
		   return(1);
	case REG:
		return(0);

	default:
		return(1);

		}

	}

NODE *
bcon( i ){ /* make a constant node with value i */
	register NODE *p;

	p = block( ICON, NIL, NIL, INT, 0, INT );
	p->tn.lval = i;
	p->tn.rval = NONAME;
	return( clocal(p) );
	}

NODE *
bpsize(p) register NODE *p; {
	return( offcon( psize(p), p->in.type, p->fn.cdim, p->fn.csiz ) );
	}

OFFSZ
psize( p ) NODE *p; {
	/* p is a node of type pointer; psize returns the
	   size of the thing pointed to */

	if( !ISPTR(p->in.type) ){
		uerror( "pointer required");
		return( SZINT );
		}
	/* note: no pointers to fields */
	return( tsize( DECREF(p->in.type), p->fn.cdim, p->fn.csiz ) );
	}

NODE *
convert( p, f )  register NODE *p; {
	/*  convert an operand of p
	    f is either CVTL or CVTR
	    operand has type int, and is converted by the size of the other side
	    */

	register NODE *q, *r;

	q = (f==CVTL)?p->in.left:p->in.right;

	r = block( PMCONV,
		q, bpsize(f==CVTL?p->in.right:p->in.left), INT, 0, INT );
	r = clocal(r);
	if( f == CVTL )
		p->in.left = r;
	else
		p->in.right = r;
	return(p);

	}

#ifndef econvert
econvert( p ) register NODE *p; {

	/* change enums to ints, or appropriate types */

	register TWORD ty;

	if( (ty=BTYPE(p->in.type)) == ENUMTY || ty == MOETY ) {
		if( dimtab[ p->fn.csiz ] == SZCHAR ) ty = CHAR;
		else if( dimtab[ p->fn.csiz ] == SZINT ) ty = INT;
		else if( dimtab[ p->fn.csiz ] == SZSHORT ) ty = SHORT;
		else ty = LONG;
		ty = ctype( ty );
		p->fn.csiz = ty;
		MODTYPE(p->in.type,ty);
		if( p->in.op == ICON && ty != LONG )
			p->in.type = p->fn.csiz = INT;
		}
	}
#endif

NODE *
pconvert( p ) register NODE *p; {

	/* if p should be changed into a pointer, do so */

	if( ISARY( p->in.type) ){
		p->in.type = DECREF( p->in.type );
		++p->fn.cdim;
		return( buildtree( UNARY AND, p, NIL ) );
		}
	if( ISFTN( p->in.type) )
		return( buildtree( UNARY AND, p, NIL ) );

	return( p );
	}

NODE *
oconvert(p) register NODE *p; {
	/* convert the result itself: used for pointer and unsigned */

	switch(p->in.op) {

	case LE:
	case LT:
	case GE:
	case GT:
		if( ISUNSIGNED(p->in.left->in.type) || ISUNSIGNED(p->in.right->in.type) )  p->in.op += (ULE-LE);
	case EQ:
	case NE:
		return( p );

	case MINUS:
		return(  clocal( block( PVCONV,
			p, bpsize(p->in.left), INT, 0, INT ) ) );
		}

	cerror( "illegal oconvert: %d", p->in.op );

	return(p);
	}

NODE *
ptmatch(p)  register NODE *p; {

	/* makes the operands of p agree; they are
	   either pointers or integers, by this time */
	/* with MINUS, the sizes must be the same */
	/* with COLON, the types must be the same */

 	TWORD ta, t1, t2, t;
	int o, d2, d, s2, s;

	o = p->in.op;
	t = t1 = p->in.left->in.type;
	t2 = p->in.right->in.type;
 	ta = p->in.left->in.typattr;
	d = p->in.left->fn.cdim;
	d2 = p->in.right->fn.cdim;
	s = p->in.left->fn.csiz;
	s2 = p->in.right->fn.csiz;

	switch( o ){

	case ASSIGN:
	case RETURN:
	case CAST:
		{  break; }

	case MINUS:
		{  if( psize(p->in.left) != psize(p->in.right) ){
			uerror( "illegal pointer subtraction");
			}
		   break;
		   }
	case COLON:
		{  if( t1 != t2 ) uerror( "illegal types in :");
		   break;
		   }
	default:  /* must work harder: relationals or comparisons */

		if( !ISPTR(t1) ){
			t = t2;
			d = d2;
			s = s2;
			break;
			}
		if( !ISPTR(t2) ){
			break;
			}

		/* both are pointers */
		if( talign(t2,s2) < talign(t,s) ){
			t = t2;
			s = s2;
			}
		break;
		}

	p->in.left = makety( p->in.left, t, d, s );
	p->in.right = makety( p->in.right, t, d, s );
	if( o!=MINUS && !logop(o) ){

		p->in.type = t;
		p->fn.cdim = d;
		p->fn.csiz = s;
		}

 	if (o == CAST) p->in.right->in.typattr = ta;
	return(clocal(p));
	}

int tdebug = 0;

NODE *
tymatch(p)  register NODE *p; {

	/* satisfy the types of various arithmetic binary ops */

	/* rules are:
		if assignment, op, type of LHS
		if any float or doubles, make double
		if any longs, make long
		otherwise, make int
		if either operand is unsigned, the result is...
	*/

	register TWORD t1, t2, t, tu;
	register o, u;
	o = p->in.op;

	t1 = p->in.left->in.type;
	t2 = p->in.right->in.type;
	if( (t1==UNDEF || t2==UNDEF) && o!=CAST )
		uerror("void type illegal in expression");

	u = 0;
	if( ISUNSIGNED(t1) ){
		u = 1;
		t1 = DEUNSIGN(t1);
		}
	if( ISUNSIGNED(t2) ){
		u = 1;
		t2 = DEUNSIGN(t2);
		}

	if( ( t1 == CHAR || t1 == SHORT ) && o!= RETURN ) t1 = INT;
	if( t2 == CHAR || t2 == SHORT ) t2 = INT;

	/* vdp009 - if floating point is not to be promoted 
	 * up to double (fflag) we check for that here 
	 */
 
	if ((fflag) && (t1==DOUBLE || t2==DOUBLE)) 
		t = DOUBLE; 
	else if ((fflag) && (t1==FLOAT || t2==FLOAT)) 
		t = FLOAT;
	else if( t1==DOUBLE || t1==FLOAT || t2==DOUBLE || t2==FLOAT )
		 t = DOUBLE;
	else if( t1==LONG || t2==LONG ) 
		t = LONG;
	else t = INT;

	if( asgop(o) ){

		/*
		 *  We use the right hand side to determine which operand
		 *  must be converted.  This fixes the problem of