lint.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static	char	*sccsid = "@(#)lint.c	4.2	(ULTRIX)	12/9/87";
#endif lint

/************************************************************************
 *									*
 *			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				*
 *									*
 *	David Metsky, 2-Jul-87, 2.4(2.2)
 * 003	Made it OK to do a greater than of an unsigned number against	*
 *	0.								*
 *									*
 *	Lu Anne Van de Pas, 13-Mar-86, 2.0				*
 * 002  Added functions cvtfloat and cvtdouble to distinguish between   *
 *	double and float constants.					*
 *	David L. Ballenger, 14-Nov-1984, 1.2				*
 * 001	Add definitions of ALSTACK so that code shared with PCC will	*
 *	work								*
 *									*
 ************************************************************************/

# include "mfile1"

# include "lmanifest"

# include <ctype.h>

# define VAL 0
# define EFF 1

/* these are appropriate for the -p flag */
int  SZCHAR = 8;
int  SZINT = 16;
int  SZFLOAT = 32;
int  SZDOUBLE = 64;
int  SZLONG = 32;
int  SZSHORT = 16;
int SZPOINT = 16;
int ALCHAR = 8;
int ALINT = 16;
int ALFLOAT = 32;
int ALDOUBLE = 64;
int ALLONG = 32;
int ALSHORT = 16;
int ALPOINT = 16;
int ALSTRUCT = 16;
int ALSTACK = 32;

int vflag = 1;  /* tell about unused argments */
int xflag = 0;  /* tell about unused externals */
int argflag = 0;  /* used to turn off complaints about arguments */
int libflag = 0;  /* used to generate library descriptions */
int vaflag = -1;  /* used to signal functions with a variable number of args */
int aflag = 0;  /* used to check precision of assignments */
int zflag = 0;  /* no 'structure never defined' error */
int Cflag = 0;  /* filter out certain output, for generating libraries */
char *libname = 0;  /* name of the library we're generating */

	/* flags for the "outdef" function */
# define USUAL (-101)
# define DECTY (-102)
# define NOFILE (-103)
# define SVLINE (-104)

# define LNAMES 250

struct lnm {
	short lid, flgs;
	}  lnames[LNAMES], *lnp;

contx( p, down, pl, pr ) register NODE *p; register *pl, *pr; {

	*pl = *pr = VAL;
	switch( p->in.op ){

	case ANDAND:
	case OROR:
	case QUEST:
		*pr = down;
		break;

	case SCONV:
	case PCONV:
	case COLON:
		*pr = *pl = down;
		break;

	case COMOP:
		*pl = EFF;
		*pr = down;

	case FORCE:
	case INIT:
	case UNARY CALL:
	case STCALL:
	case UNARY STCALL:
	case CALL:
	case UNARY FORTCALL:
	case FORTCALL:
	case CBRANCH:
		break;

	default:
		if( asgop(p->in.op) ) break;
		if( p->in.op == UNARY MUL && ( p->in.type == STRTY || p->in.type == UNIONTY || p->in.type == UNDEF) ) {
		/* struct x f( );  main( ) {  (void) f( ); }
		 * the the cast call appears as U* UNDEF
		 */
			break;  /* the compiler does this... */
			}
		if( down == EFF && hflag ) werror( "null effect" );

		}
	}

ecode( p ) NODE *p; {
	/* compile code for p */

	fwalk( p, contx, EFF );
	lnp = lnames;
	lprt( p, EFF, 0 );
	}

ejobcode( flag ){
	/* called after processing each job */
	/* flag is nonzero if errors were detected */
	register k;
	register struct symtab *p;

	for( p=stab; p< &stab[SYMTSZ]; ++p ){

		if( p->stype != TNULL ) {

			if( p->stype == STRTY || p->stype == UNIONTY ){
				if( !zflag && dimtab[p->sizoff+1] < 0 ){
					/* never defined */
#ifndef FLEXNAMES
					if( hflag ) werror( "struct/union %.8s never defined", p->sname );
#else
					if( hflag ) werror( "struct/union %s never defined", p->sname );
#endif
					}
				}

			switch( p->sclass ){
			
			case STATIC:
				if( p->suse > 0 ){
					k = lineno;
					lineno = p->suse;
#ifndef FLEXNAMES
					uerror( "static variable %.8s unused",
#else
					uerror( "static variable %s unused",
#endif
						p->sname );
					lineno = k;
					break;
					}
				/* no statics in libraries */
				if( Cflag ) break;

			case EXTERN:
			case USTATIC:
				/* with the xflag, worry about externs not used */
				/* the filename may be wrong here... */
				if( xflag && p->suse >= 0 && !libflag ){
					outdef( p, LDX, NOFILE );
					}
			
			case EXTDEF:
				if( p->suse < 0 ){  /* used */
					outdef( p, LUM, SVLINE );
					}
				break;
				}
			
			}

		}
	exit( 0 );
	}

astype( t, i ) ATYPE *t; {
	TWORD tt;
	int j, k=0, l=0;

	if( (tt=BTYPE(t->aty))==STRTY || tt==UNIONTY ){
		if( i<0 || i>= DIMTABSZ-3 ){
			werror( "lint's little mind is blown" );
			}
		else {
			j = dimtab[i+3];
			if( j<0 || j>SYMTSZ ){
				k = dimtab[i];
				l = X_NONAME | stab[j].suse;
				}
			else {
				if( stab[j].suse <= 0 ) {
#ifndef FLEXNAMES
					werror( "no line number for %.8s",
#else
					werror( "no line number for %s",
#endif
						stab[j].sname );
					}
				else {
					k = dimtab[i];
#ifdef FLEXNAMES
					l = hashstr(stab[j].sname);
#else
					l = hashstr(stab[j].sname, LCHNM);
#endif
					}
				}
			}
		
		t->extra = k;
		t->extra1 = l;
		return( 1 );
		}
	else return( 0 );
	}

bfcode( a, n ) int a[]; {
	/* code for the beginning of a function; a is an array of
		indices in stab for the arguments; n is the number */
	/* this must also set retlab */
	register i;
	register struct symtab *cfp;
	static ATYPE t;

	retlab = 1;

	cfp = &stab[curftn];

	/* if creating library, don't do static functions */
	if( Cflag && cfp->sclass == STATIC ) return;

	/* if variable number of arguments, only print the ones which will be checked */
	if( vaflag > 0 ){
		if( n < vaflag ) werror( "declare the VARARGS arguments you want checked!" );
		else n = vaflag;
		}
	fsave( ftitle );
	if( cfp->sclass == STATIC ) outdef( cfp, LST, vaflag>=0?-n:n );
	else outdef( cfp, libflag?LIB:LDI, vaflag>=0?-n:n );
	vaflag = -1;

	/* output the arguments */
	if( n ){
		for( i=0; i<n; ++i ) {
			t.aty = stab[a[i]].stype;
			t.extra = 0;
			t.extra1 = 0;
			if( !astype( &t, stab[a[i]].sizoff ) ) {
				switch( t.aty ){

				case ULONG:
					break;

				case CHAR:
				case SHORT:
					t.aty = INT;
					break;

				case UCHAR:
				case USHORT:
				case UNSIGNED:
					t.aty = UNSIGNED;
					break;

					}
				}
			fwrite( (char *)&t, sizeof(ATYPE), 1, stdout );
			}
		}
	}

ctargs( p ) NODE *p; {
	/* count arguments; p points to at least one */
	/* the arguemnts are a tower of commas to the left */
	register c;
	c = 1; /* count the rhs */
	while( p->in.op == CM ){
		++c;
		p = p->in.left;
		}
	return( c );
	}

lpta( p ) NODE *p; {
	static ATYPE t;

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

	t.aty = p->in.type;
	t.extra = (p->in.op==ICON);
	t.extra1 = 0;

	if( !astype( &t, p->in.csiz ) ) {
		switch( t.aty ){

			case CHAR:
			case SHORT:
				t.aty = INT;
			case LONG:
			case ULONG:
			case INT:
			case UNSIGNED:
				break;

			case UCHAR:
			case USHORT:
				t.aty = UNSIGNED;
				break;

			case FLOAT:
				t.aty = DOUBLE;
				t.extra = 0;
				break;

			default:
				t.extra = 0;
				break;
			}
		}
	fwrite( (char *)&t, sizeof(ATYPE), 1, stdout );
	}

# define VALSET 1
# define VALUSED 2
# define VALASGOP 4
# define VALADDR 8

lprt( p, down, uses ) register NODE *p; {
	register struct symtab *q;
	register id;
	register acount;
	register down1, down2;
	register use1, use2;
	register struct lnm *np1, *np2;

	/* first, set variables which are set... */

	use1 = use2 = VALUSED;
	if( p->in.op == ASSIGN ) use1 = VALSET;
	else if( p->in.op == UNARY AND ) use1 = VALADDR;
	else if( asgop( p->in.op ) ){ /* =ops */
		use1 = VALUSED|VALSET;
		if( down == EFF ) use1 |= VALASGOP;
		}


	/* print the lines for lint */

	down2 = down1 = VAL;
	acount = 0;

	switch( p->in.op ){

	case EQ:
	case NE:
	case GT:
	case GE:
	case LT:
	case LE:
		if( p->in.left->in.type == CHAR && p->in.right->in.op==ICON && p->in.right->tn.lval < 0 ){
			werror( "nonportable character comparison" );
			}
		if( (p->in.op==EQ || p->in.op==NE ) && ISUNSIGNED(p->in.left->in.type) && p->in.right->in.op == ICON ){
			if( p->in.right->tn.lval < 0 && p->in.right->tn.rval == NONAME && !ISUNSIGNED(p->in.right->in.type) ){
				werror( "comparison of unsigned with negative constant" );
				}
			}
		break;

	case UGE:
	case ULT:
		if( p->in.right->in.op == ICON && p->in.right->tn.lval == 0 && p->in.right->tn.rval == NONAME ){
			werror( "unsigned comparison with 0?" );
			break;
			}
	case ULE:
		if( p->in.right->in.op == ICON && p->in.right->tn.lval <= 0 && !ISUNSIGNED(p->in.right->in.type) && p->in.right->tn.rval == NONAME ){
			werror( "degenerate unsigned comparison" );
			}
		break;

	case UGT:			/* 003 - dnm */
		if( p->in.right->in.op == ICON && p->in.right->tn.lval < 0 && !ISUNSIGNED(p->in.right->in.type) && p->in.right->tn.rval == NONAME ){
			werror( "degenerate unsigned comparison" );
			}
		break;

	case COMOP:
		down1 = EFF;

	case ANDAND:
	case OROR:
	case QUEST:
		down2 = down;
		/* go recursively left, then right  */
		np1 = lnp;
		lprt( p->in.left, down1, use1 );
		np2 = lnp;
		lprt( p->in.right, down2, use2 );
		lmerge( np1, np2, 0 );
		return;

	case SCONV:
	case PCONV:
	case COLON:
		down1 = down2 = down;
		break;

	case CALL:
	case STCALL:
	case FORTCALL:
		acount = ctargs( p->in.right );
	case UNARY CALL:
	case UNARY STCALL:
	case UNARY FORTCALL:
		if( p->in.left->in.op == ICON && (id=p->in.left->tn.rval) != NONAME ){ /* used to be &name */
			struct symtab *sp = &stab[id];
			int lty;

			fsave( ftitle );
			/*
			 * if we're generating a library -C then
			 * we don't want to output references to functions
			 */
			if( Cflag ) break;
			/*  if a function used in an effects context is
			 *  cast to type  void  then consider its value
			 *  to have been disposed of properly
			 *  thus a call of type  undef  in an effects
			 *  context is construed to be used in a value
			 *  context
			 */
			if ((down == EFF) && (p->in.type != UNDEF)) {
				lty = LUE;
			} else if (down == EFF) {
				lty = LUV | LUE;
			} else {
				lty = LUV;
			}
			outdef( sp, lty, acount );
			if( acount ) {
				lpta( p->in.right );
				}
			}
		break;

	case ICON:
		/* look for &name case */
		if( (id = p->tn.rval) >= 0 && id != NONAME ){
			q = &stab[id];
			q->sflags |= (SREF|SSET);
			q->suse = -lineno;
			}
		return;

	case NAME:
		if( (id = p->tn.rval) >= 0 && id != NONAME ){
			q = &stab[id];
			if( (uses&VALUSED) && !(q->sflags&SSET) ){
				if( q->sclass == AUTO || q->sclass == REGISTER ){
					if( !ISARY(q->stype ) && !ISFTN(q->stype) && q->stype!=STRTY && q->stype!=UNIONTY ){
#ifndef FLEXNAMES
						werror( "%.8s may be used before set", q->sname );
#else
						werror( "%s may be used before set", q->sname );
#endif
						q->sflags |= SSET;
						}
					}
				}
			if( uses & VALASGOP ) break;  /* not a real use */
			if( uses & VALSET ) q->sflags |= SSET;
			if( uses & VALUSED ) q->sflags |= SREF;
			if( uses & VALADDR ) q->sflags |= (SREF|SSET);
			if( p->tn.lval == 0 ){
				lnp->lid = id;
				lnp->flgs = (uses&VALADDR)?0:((uses&VALSET)?VALSET:VALUSED);
				if( ++lnp >= &lnames[LNAMES] ) --lnp;
				}
			}
		return;

		}

	/* recurse, going down the right side first if we can */

	switch( optype(p->in.op) ){

	case BITYPE:
		np1 = lnp;
		lprt( p->in.right, down2, use2 );
	case UTYPE:
		np2 = lnp;
		lprt( p->in.left, down1, use1 );
		}

	if( optype(p->in.op) == BITYPE ){
		if( p->in.op == ASSIGN && p->in.left->in.op == NAME ){ /* special case for a =  .. a .. */
			lmerge( np1, np2, 0 );
			}
		else lmerge( np1, np2, p->in.op != COLON );
		/* look for assignments to fields, and complain */
		if( p->in.op == ASSIGN && p->in.left->in.op == FLD && p->in.right->in.op == ICON ) fldcon( p );
		}

	}

lmerge( np1, np2, flag ) struct lnm *np1, *np2; {
	/* np1 and np2 point to lists of lnm members, for the two sides
	 * of a binary operator
	 * flag is 1 if commutation is possible, 0 otherwise
	 * lmerge returns a merged list, starting at np1, resetting lnp
	 * it also complains, if appropriate, about side effects
	 */