local.c

来自「<B>Digital的Unix操作系统VAX 4.2源码</B>」· C语言 代码 · 共 464 行

#ifndef lint
static char	*sccsid = " @(#)local.c	4.1	(ULTRIX)	7/17/90";
#endif lint

/************************************************************************
 *									*
 *			Copyright (c) 1986 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		14-Jan-86
*
* 001	Added from BSD 4.3 version as part of upgrade.
*
*	Based on:	local.c		1.8		8/23/85
*
*************************************************************************/

# include "pass1.h"

/*	this file contains code which is dependent on the target machine */

NODE *
cast( p, t ) register NODE *p; TWORD t; {
	/* cast node p to type t */

	p = buildtree( CAST, block( NAME, NIL, NIL, t, 0, (int)t ), p );
	p->in.left->in.op = FREE;
	p->in.op = FREE;
	return( p->in.right );
	}

NODE *
clocal(p) NODE *p; {

	/* this is called to do local transformations on
	   an expression tree preparitory to its being
	   written out in intermediate code.
	*/

	/* the major essential job is rewriting the
	   automatic variables and arguments in terms of
	   REG and OREG nodes */
	/* conversion ops which are not necessary are also clobbered here */
	/* in addition, any special features (such as rewriting
	   exclusive or) are easily handled here as well */

	register struct symtab *q;
	register NODE *r;
	register o;
	register m, ml;

	switch( o = p->in.op ){

	case NAME:
		if( p->tn.rval < 0 ) { /* already processed; ignore... */
			return(p);
			}
		q = &stab[p->tn.rval];
		switch( q->sclass ){

		case AUTO:
		case PARAM:
			/* fake up a structure reference */
			r = block( REG, NIL, NIL, PTR+STRTY, 0, 0 );
			r->tn.lval = 0;
			r->tn.rval = (q->sclass==AUTO?STKREG:ARGREG);
			p = stref( block( STREF, r, p, 0, 0, 0 ) );
			break;

		case ULABEL:
		case LABEL:
		case STATIC:
			if( q->slevel == 0 ) break;
			p->tn.lval = 0;
			p->tn.rval = -q->offset;
			break;

		case REGISTER:
			p->in.op = REG;
			p->tn.lval = 0;
			p->tn.rval = q->offset;
			break;

			}
		break;

	case PCONV:
		/* do pointer conversions for char and longs */
		ml = p->in.left->in.type;
		if( ( ml==CHAR || ml==UCHAR || ml==SHORT || ml==USHORT ) && p->in.left->in.op != ICON ) break;

		/* pointers all have the same representation; the type is inherited */

		p->in.left->in.type = p->in.type;
		p->in.left->fn.cdim = p->fn.cdim;
		p->in.left->fn.csiz = p->fn.csiz;
		p->in.op = FREE;
		return( p->in.left );

	case SCONV:
		m = (p->in.type == FLOAT || p->in.type == DOUBLE );
		ml = (p->in.left->in.type == FLOAT || p->in.left->in.type == DOUBLE );
		o = p->in.left->in.op;
		if( (o == FCON || o == DCON) && ml && !m ) {
			/* float type to int type */
			r = block( ICON, (NODE *)NULL, (NODE *)NULL, INT, 0, 0 );
			if( o == FCON )
				r->tn.lval = (int) p->in.left->fpn.fval;
			else
				r->tn.lval = (int) p->in.left->dpn.dval;
			r->tn.rval = NONAME;
			p->in.left->in.op = FREE;
			p->in.left = r;
			}
		else
#ifdef SPRECC
			if ( ml || m )
#else
			if ( ml != m )
#endif
				break;

		/* now, look for conversions downwards */

		m = p->in.type;
		ml = p->in.left->in.type;
		if( p->in.left->in.op == ICON ){ /* simulate the conversion here */
			CONSZ val;
			val = p->in.left->tn.lval;
			switch( m ){
			case CHAR:
				p->in.left->tn.lval = (char) val;
				break;
			case UCHAR:
				p->in.left->tn.lval = val & 0XFF;
				break;
			case USHORT:
				p->in.left->tn.lval = val & 0XFFFFL;
				break;
			case SHORT:
				p->in.left->tn.lval = (short)val;
				break;
			case UNSIGNED:
				p->in.left->tn.lval = val & 0xFFFFFFFFL;
				break;
			case INT:
				p->in.left->tn.lval = (int)val;
				break;
				}
			p->in.left->in.type = m;
			}
		else if( m != FLOAT && m != DOUBLE )
			break;

		/* clobber conversion */
		p->in.op = FREE;
		return( p->in.left );  /* conversion gets clobbered */

	case PVCONV:
	case PMCONV:
		if( p->in.right->in.op != ICON ) cerror( "bad conversion", 0);
		p->in.op = FREE;
		return( buildtree( o==PMCONV?MUL:DIV, p->in.left, p->in.right ) );

	case RS:
	case ASG RS:
		/* convert >> to << with negative shift count */
		/* only if type of left operand is not unsigned */

		if( ISUNSIGNED(p->in.left->in.type) ) break;
		if( p->in.right->in.op != UNARY MINUS )
			p->in.right = buildtree( UNARY MINUS, p->in.right, NIL );
		else {
			r = p->in.right;
			p->in.right = p->in.right->in.left;
			r->in.op = FREE;
		}
		if( p->in.op == RS ) p->in.op = LS;
		else p->in.op = ASG LS;
		break;

	case FLD:
		/* make sure that the second pass does not make the
		   descendant of a FLD operator into a doubly indexed OREG */

		if( p->in.left->in.op == UNARY MUL
				&& (r=p->in.left->in.left)->in.op == PCONV)
			if( r->in.left->in.op == PLUS || r->in.left->in.op == MINUS ) 
				if( ISPTR(r->in.type) ) {
					if( ISUNSIGNED(p->in.left->in.type) )
						p->in.left->in.type = UCHAR;
					else
						p->in.left->in.type = CHAR;
				}
		break;
		}

	return(p);
	}

andable( p ) NODE *p; {
	return(1);  /* all names can have & taken on them */
	}

cendarg(){ /* at the end of the arguments of a ftn, set the automatic offset */
	autooff = AUTOINIT;
	}

cisreg( t ) TWORD t; { /* is an automatic variable of type t OK for a register variable */

#ifdef TRUST_REG_CHAR_AND_REG_SHORT
	if( t==INT || t==UNSIGNED || t==LONG || t==ULONG	/* tbl */
		|| t==CHAR || t==UCHAR || t==SHORT 		/* tbl */
		|| t==USHORT || ISPTR(t)) return(1);		/* tbl */
#else
	if( t==INT || t==UNSIGNED || t==LONG || t==ULONG	/* wnj */
#ifdef SPRECC
		|| t==FLOAT
#endif
		|| ISPTR(t)) return (1);			/* wnj */
#endif
	return(0);
	}

NODE *
offcon( off, t, d, s ) OFFSZ off; TWORD t; {

	/* return a node, for structure references, which is suitable for
	   being added to a pointer of type t, in order to be off bits offset
	   into a structure */

	register NODE *p;

	/* t, d, and s are the type, dimension offset, and sizeoffset */
	/* in general they  are necessary for offcon, but not on H'well */

	p = bcon(0);
	p->tn.lval = off/SZCHAR;
	return(p);

	}


static inwd	/* current bit offsed in word */;
static word	/* word being built from fields */;

incode( p, sz ) register NODE *p; {

	/* generate initialization code for assigning a constant c
		to a field of width sz */
	/* we assume that the proper alignment has been obtained */
	/* inoff is updated to have the proper final value */
	/* we also assume sz  < SZINT */

	if((sz+inwd) > SZINT) cerror("incode: field > int");
	word |= ((unsigned)(p->tn.lval<<(32-sz))) >> (32-sz-inwd);
	inwd += sz;
	inoff += sz;
	if(inoff%SZINT == 0) {
		printf( "	.long	0x%x\n", word);
		word = inwd = 0;
		}
	}

fincode( d, sz ) double d; {
	/* output code to initialize space of size sz to the value d */
	/* the proper alignment has been obtained */
	/* inoff is updated to have the proper final value */
	/* on the target machine, write it out in octal! */


	printf("	%s	0%c%.20e\n", sz == SZDOUBLE ? ".double" : ".float",
		sz == SZDOUBLE ? 'd' : 'f', d);
	inoff += sz;
	}

cinit( p, sz ) NODE *p; {
	NODE *l;

	/*
	 * as a favor (?) to people who want to write
	 *     int i = 9600/134.5;
	 * we will, under the proper circumstances, do
	 * a coersion here.
	 */
	switch (p->in.type) {
	case INT:
	case UNSIGNED:
		l = p->in.left;
		if (l->in.op != SCONV ||
		    (l->in.left->tn.op != DCON && l->in.left->tn.op != FCON))
			break;
		l->in.op = FREE;
		l = l->in.left;
		l->tn.lval = l->tn.op == DCON ? (long)(l->dpn.dval) :
			(long)(l->fpn.fval);
		l->tn.rval = NONAME;
		l->tn.op = ICON;
		l->tn.type = INT;
		p->in.left = l;
		break;
	}
	/* arrange for the initialization of p into a space of size sz */
	/* the proper alignment has been opbtained */
	/* inoff is updated to have the proper final value */
	ecode( p );
	inoff += sz;
	}

vfdzero( n ){ /* define n bits of zeros in a vfd */

	if( n <= 0 ) return;

	inwd += n;
	inoff += n;
	if( inoff%ALINT ==0 ) {
		printf( "	.long	0x%x\n", word );
		word = inwd = 0;
		}
	}

char *
exname( p ) char *p; {
	/* make a name look like an external name in the local machine */

#ifndef FLEXNAMES
	static char text[NCHNAM+1];
#else
	static char text[BUFSIZ+1];
#endif

	register i;

	text[0] = '_';
#ifndef FLEXNAMES
	for( i=1; *p&&i<NCHNAM; ++i )
#else
	for( i=1; *p; ++i )
#endif
		text[i] = *p++;

	text[i] = '\0';
#ifndef FLEXNAMES
	text[NCHNAM] = '\0';  /* truncate */
#endif

	return( text );
	}

ctype( type ) TWORD type;
	{ /* map types which are not defined on the local machine */
	switch( BTYPE(type) ){

	case LONG:
		MODTYPE(type,INT);
		break;

	case ULONG:
		MODTYPE(type,UNSIGNED);
		}
	return( type );
	}

noinit() { /* curid is a variable which is defined but
	is not initialized (and not a function );
	This routine returns the stroage class for an uninitialized declaration */

	return(EXTERN);

	}

commdec( id ){ /* make a common declaration for id, if reasonable */
	register struct symtab *q;
	OFFSZ off, tsize();

	q = &stab[id];
	printf( "	.comm	%s,", exname( q->sname ) );
	off = tsize( q->stype, q->dimoff, q->sizoff );
	printf( CONFMT, off/SZCHAR );
	printf( "\n" );
	}

isitlong( cb, ce ){ /* is lastcon to be long or short */
	/* cb is the first character of the representation, ce the last */

	if( ce == 'l' || ce == 'L' ||
		lastcon >= (1L << (SZINT-1) ) ) return (1);
	return(0);
	}


isitfloat( s ) char *s; {
	union cvt {
		double	d;
		int	n[2];
	} cvt;
	double atof();

	/* avoid floating point exception for double -> float conversions */
	dcon = cvt.d = atof(s);
	if( cvt.n[1] == 0 ){
		fcon = dcon;
		return( FCON );
		}
	return( DCON );
	}

ecode( p ) NODE *p; {

	/* walk the tree and write out the nodes.. */

	if( nerrors ) return;
	p2tree( p );
	p2compile( p );
	}

#ifndef ONEPASS
tlen(p) NODE *p; 
{
	switch(p->in.type) {
		case CHAR:
		case UCHAR:
			return(1);
			
		case SHORT:
		case USHORT:
			return(2);
			
		case DOUBLE:
			return(8);
			
		default:
			return(4);
		}
	}
#endif