match.c

<B>Digital的Unix操作系统VAX 4.2源码</B>

#ifndef lint
static	char	*sccsid = "@(#)match.c	1.3	(ULTRIX)	3/12/86";
#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
*	Lu anne Van de Pas 02-mar-86
* vdp003 - added support for doing f floating arithmetic in f float when
*	fflag is set. Uses the productions with need FLOATFLG. Also 
* 	added qdebug which prints out the table production the was matched
*	
*	Rich Phillips  8-17-84
* RAP002  Add code to put out code for UNARY CALL's to _asm.
*
*	Rich Phillips  7-11-84
* RAP001  Print an error message when the register number in tshape
*	  is out of bounds. If it happens, its probably because oreg is
*	  changed to a register when a structure is passed as a parameter
*	  for some reason (see genargs in order.c).
*
*************************************************************************/
# include "mfile2"

# ifdef WCARD1
# ifdef WCARD2
# define NOINDIRECT
# endif
# endif

extern qdebug;		/*vdp003 print out the code template matched*/
extern vdebug;
extern int fflag; 	/*vdp003 floating point */ 
int fldsz, fldshf;

static int mamask[] = { /* masks for matching dope with shapes */
	SIMPFLG,		/* OPSIMP */
	SIMPFLG|ASGFLG,		/* ASG OPSIMP */
	COMMFLG,	/* OPCOMM */
	COMMFLG|ASGFLG,	/* ASG OPCOMM */
	MULFLG,		/* OPMUL */
	MULFLG|ASGFLG,	/* ASG OPMUL */
	DIVFLG,		/* OPDIV */
	DIVFLG|ASGFLG,	/* ASG OPDIV */
	UTYPE,		/* OPUNARY */
	TYFLG,		/* ASG OPUNARY is senseless */
	LTYPE,		/* OPLEAF */
	TYFLG,		/* ASG OPLEAF is senseless */
	0,		/* OPANY */
	ASGOPFLG|ASGFLG,	/* ASG OPANY */
	LOGFLG,		/* OPLOG */
	TYFLG,		/* ASG OPLOG is senseless */
	FLOFLG,		/* OPFLOAT */
	FLOFLG|ASGFLG,	/* ASG OPFLOAT */
	SHFFLG,		/* OPSHFT */
	SHFFLG|ASGFLG,	/* ASG OPSHIFT */
	SPFLG,		/* OPLTYPE */
	TYFLG,		/* ASG OPLTYPE is senseless */
	};

int sdebug = 0;

tshape( p, shape ) NODE *p; {
	/* return true if shape is appropriate for the node p
	   side effect for SFLD is to set up fldsz,etc */
	register o, mask;

	o = p->in.op;

# ifndef BUG3
	if( sdebug ){
		printf( "tshape( %o, %o), op = %d\n", p, shape, o );
		}
# endif

	if( shape & SPECIAL ){

		switch( shape ){

		case SZERO:
		case SONE:
		case SMONE:
		case SSCON:
		case SCCON:
			if( o != ICON || p->in.name[0] ) return(0);
			if( p->tn.lval == 0 && shape == SZERO ) return(1);
			else if( p->tn.lval == 1 && shape == SONE ) return(1);
			else if( p->tn.lval == -1 && shape == SMONE ) return(1);
			else if( p->tn.lval > -129 && p->tn.lval < 128 && shape == SCCON ) return(1);
			else if( p->tn.lval > -32769 && p->tn.lval < 32768 && shape == SSCON ) return(1);
			else return(0);

		case SSOREG:	/* non-indexed OREG */
			if( o == OREG && !R2TEST(p->tn.rval) ) return(1);
			else return(0);

		default:
# ifdef MULTILEVEL
			if( shape & MULTILEVEL )
				return( mlmatch(p,shape,0) );
			else
# endif
			return( special( p, shape ) );
			}
		}

	if( shape & SANY ) return(1);

	if( (shape&INTEMP) && shtemp(p) ) return(1);

	if( (shape&SWADD) && (o==NAME||o==OREG) ){
		if( BYTEOFF(p->tn.lval) ) return(0);
		}

# ifdef WCARD1
	if( shape & WCARD1 )
		return( wcard1(p) & shape );
# endif

# ifdef WCARD2
	if( shape & WCARD2 )
		return( wcard2(p) & shape );
# endif
	switch( o ){

	case NAME:
		return( shape&SNAME );
	case ICON:
		mask = SCON;
		return( shape & mask );

	case FLD:
		if( shape & SFLD ){
			if( !flshape( p->in.left ) ) return(0);
			/* it is a FIELD shape; make side-effects */
			o = p->tn.rval;
			fldsz = UPKFSZ(o);
# ifdef RTOLBYTES
			fldshf = UPKFOFF(o);
# else
			fldshf = SZINT - fldsz - UPKFOFF(o);
# endif
			return(1);
			}
		return(0);

	case CCODES:
		return( shape&SCC );

	case REG:
		/* distinctions:
		SAREG	any scalar register
		STAREG	any temporary scalar register
		SBREG	any lvalue (index) register
		STBREG	any temporary lvalue register
		*/
		mask = isbreg( p->tn.rval ) ? SBREG : SAREG;
		/* RAP001 */
		if (p->tn.rval >=REGSZ ) 
			cerror ("incorrect register number in tshape");

		if( istreg( p->tn.rval ) && busy[p->tn.rval]<=1 ) mask |= mask==SAREG ? STAREG : STBREG;
		return( shape & mask );

	case OREG:
		return( shape & SOREG );

# ifndef NOINDIRECT
	case UNARY MUL:
		/* return STARNM or STARREG or 0 */
		return( shumul(p->in.left) & shape );
# endif

		}

	return(0);
	}

int tdebug = 0;

ttype( t, tword ) TWORD t; {
	/* does the type t match tword */

	if( tword & TANY ) return(1);

	if( t == UNDEF ) t=INT; /* void functions eased thru tables */
# ifndef BUG3
	if( tdebug ){
		printf( "ttype( %o, %o )\n", t, tword );
		}
# endif
	if( ISPTR(t) && (tword&TPTRTO) ) {
		do {
			t = DECREF(t);
		} while ( ISARY(t) );
			/* arrays that are left are usually only
			   in structure references... */
		return( ttype( t, tword&(~TPTRTO) ) );
		}
	if( t != BTYPE(t) ) return( tword & TPOINT ); /* TPOINT means not simple! */
	if( tword & TPTRTO ) return(0);

	switch( t ){

	case CHAR:
		return( tword & TCHAR );
	case SHORT:
		return( tword & TSHORT );
	case STRTY:
	case UNIONTY:
		return( tword & TSTRUCT );
	case INT:
		return( tword & TINT );
	case UNSIGNED:
		return( tword & TUNSIGNED );
	case USHORT:
		return( tword & TUSHORT );
	case UCHAR:
		return( tword & TUCHAR );
	case ULONG:
		return( tword & TULONG );
	case LONG:
		return( tword & TLONG );
	case FLOAT:
		return( tword & TFLOAT );
	case DOUBLE:
		return( tword & TDOUBLE );
		}

	return(0);
	}

struct optab *rwtable;

struct optab *opptr[DSIZE];

setrew(){
	/* set rwtable to first value which allows rewrite */
	register struct optab *q;
	register int i;

# ifdef MULTILEVEL
	/* also initialize multi-level tree links */
	mlinit();
# endif

	for( q = table; q->op != FREE; ++q ){
		if( q->needs == REWRITE ){
			rwtable = q;
			goto more;
			}
		}
	cerror( "bad setrew" );


	more:
	for( i=0; i<DSIZE; ++i ){
		if( dope[i] ){ /* there is an op... */
			for( q=table; q->op != FREE; ++q ){
				/*  beware; things like LTYPE that match
				    multiple things in the tree must
				    not try to look at the NIL at this
				    stage of things!  Put something else
				    first in table.c  */
				/* at one point, the operator matching was 15% of the
				    total comile time; thus, the function
				    call that was here was removed...
				*/

				if( q->op < OPSIMP ){
					if( q->op==i ) break;
					}
				else {
					register opmtemp;
					if((opmtemp=mamask[q->op - OPSIMP])&SPFLG){
						if( i==NAME || i==ICON || i==OREG ) break;
						else if( shltype( i, NIL ) ) break;
						}
					else if( (dope[i]&(opmtemp|ASGFLG)) == opmtemp ) break;
					}
				}
			opptr[i] = q;
			}
		}
	}

match( p, cookie ) NODE *p; {
	/* called by: order, gencall
	   look for match in table and generate code if found unless
	   entry specified REWRITE.
	   returns MDONE, MNOPE, or rewrite specification from table */

	register struct optab *q;
	register NODE *r;

	rcount();
	if( cookie == FORREW ) q = rwtable;
	else q = opptr[p->in.op];

	for( ; q->op != FREE; ++q ){

		/* at one point the call that was here was over 15% of the total time;
		    thus the function call was expanded inline */
		if( q->op < OPSIMP ){
			if( q->op!=p->in.op ) continue;
			}
		else {
			register opmtemp;
			if((opmtemp=mamask[q->op - OPSIMP])&SPFLG){
				if( p->in.op!=NAME && p->in.op!=ICON && p->in.op!= OREG &&
					! shltype( p->in.op, p ) ) continue;
				}
			else if( (dope[p->in.op]&(opmtemp|ASGFLG)) != opmtemp ) continue;
			}

		if( !(q->visit & cookie ) ) continue;
		r = getlr( p, 'L' );			/* see if left child matches */
		if( !tshape( r, q->lshape ) ) continue;
		if( !ttype( r->in.type, q->ltype ) ) continue;
		r = getlr( p, 'R' );			/* see if right child matches */
		if( !tshape( r, q->rshape ) ) continue;
		if( !ttype( r->in.type, q->rtype ) ) continue;

		/* No match if floating point flag is not set and we have a 
		 * float production (i.e. FLOATFLG)  -ugh-  vdp003  
		 */ 
		if ((!fflag) && (q->needs & FLOATFLG) )
			 continue;  

			/* REWRITE means no code from this match but go ahead
			 * and rewrite node to help future match 
			 */
		if( q->needs & REWRITE ) return( q->rewrite );
		if( !allo( p, q ) ) continue;			/* if can't generate code, skip entry */