xref: /csrg-svn/usr.bin/pascal/src/lab.c (revision 9137)

/* Copyright (c) 1979 Regents of the University of California */

static char sccsid[] = "@(#)lab.c 1.16 11/12/82";

#include "whoami.h"
#include "0.h"
#include "tree.h"
#include "opcode.h"
#include "objfmt.h"
#ifdef PC
#   include	"pc.h"
#   include	"pcops.h"
#endif PC

/*
 * Label enters the definitions
 * of the label declaration part
 * into the namelist.
 */
label(r, l)
	int *r, l;
{
    static bool	label_order = FALSE;
    static bool	label_seen = FALSE;
#ifdef PC
	char	extname[ BUFSIZ ];
#endif PC
#ifndef PI0
	register *ll;
	register struct nl *p, *lp;

	lp = NIL;
#else
	send(REVLAB, r);
#endif
	if ( ! progseen ) {
	    level1();
	}
	line = l;
#ifndef PI1
	if (parts[ cbn ] & (CPRT|TPRT|VPRT|RPRT)){
	    if ( opt( 's' ) ) {
		standard();
		error("Label declarations should precede const, type, var and routine declarations");
	    } else {
		if ( !label_order ) {
		    label_order = TRUE;
		    warning();
		    error("Label declarations should precede const, type, var and routine declarations");
		}
	    }
	}
	if (parts[ cbn ] & LPRT) {
	    if ( opt( 's' ) ) {
		standard();
		error("All labels should be declared in one label part");
	    } else {
		if ( !label_seen ) {
		    label_seen = TRUE;
		    warning();
		    error("All labels should be declared in one label part");
		}
	    }
	}
	parts[ cbn ] |= LPRT;
#endif
#ifndef PI0
	for (ll = r; ll != NIL; ll = ll[2]) {
		l = getlab();
		p = enter(defnl(ll[1], LABEL, 0, l));
		/*
		 * Get the label for the eventual target
		 */
		p->value[1] = getlab();
		p->chain = lp;
		p->nl_flags |= (NFORWD|NMOD);
		p->value[NL_GOLEV] = NOTYET;
		p->value[NL_ENTLOC] = l;
		lp = p;
#		ifdef OBJ
		    /*
		     * This operator is between
		     * the bodies of two procedures
		     * and provides a target for
		     * gotos for this label via TRA.
		     */
		    putlab(l);
		    put(2, O_GOTO | cbn<<8, (long)p->value[1]);
#		endif OBJ
#		ifdef PC
		    /*
		     *	labels have to be .globl otherwise /lib/c2 may
		     *	throw them away if they aren't used in the function
		     *	which defines them.
		     */
		    extlabname( extname , p -> symbol , cbn );
		    putprintf( "	.globl	%s" , 0 , extname );
		    if ( cbn == 1 ) {
			stabglabel( extname , line );
		    }
#		endif PC
	}
	gotos[cbn] = lp;
#	ifdef PTREE
	    {
		pPointer	Labels = LabelDCopy( r );

		pDEF( PorFHeader[ nesting ] ).PorFLabels = Labels;
	    }
#	endif PTREE
#endif
}

#ifndef PI0
/*
 * Gotoop is called when
 * we get a statement "goto label"
 * and generates the needed tra.
 */
gotoop(s)
	char *s;
{
	register struct nl *p;
#ifdef PC
	char	extname[ BUFSIZ ];
#endif PC

	gocnt++;
	p = lookup(s);
	if (p == NIL)
		return (NIL);
#	ifdef OBJ
	    put(2, O_TRA4, (long)p->value[NL_ENTLOC]);
#	endif OBJ
#	ifdef PC
	    if ( cbn == bn ) {
		    /*
		     *	local goto.
		     */
		extlabname( extname , p -> symbol , bn );
		    /*
		     *	this is a jmp because it's a jump to a label that
		     *	has been declared global. Although this branch is
		     *	within this module the assembler will complain that
		     *	the destination is a global symbol. The complaint
		     *	arises because the assembler doesn't change jbr's
		     *	into jmp's and consequently may cause a branch
		     *	displacement overflow when the module is subsequently
		     *	linked into the rest of the program.
		     */
		putprintf( "	jmp	%s" , 0 , extname );
	    } else {
		    /*
		     *	Non-local goto.
		     *
		     *  Close all active files between top of stack and
		     *  frame at the destination level.	Then call longjmp
		     *	to unwind the stack to the destination level.
		     *
		     *	For nested routines the end is calculated as:
		     *	__disply[ bn ] . ap + sizeof( local frame )
		     *	The size of the local frame is dumped out by
		     *	the second pass as an assembler constant.
		     *	The main routine may not be compiled in this
		     *	module, so its size may not be available.
		     * 	However all of its variables will be globally
		     *	declared, so only the known runtime temporaries
		     *	will be in its stack frame.
		     */
		parts[ bn ] |= NONLOCALGOTO;
		putleaf( P2ICON , 0 , 0 , ADDTYPE( P2FTN | P2INT , P2PTR )
			, "_PCLOSE" );
		if ( bn > 1 ) {
		    p = lookup( enclosing[ bn - 1 ] );
		    sprintf( extname, "LF%d+%d", p -> value[ NL_ENTLOC ]
			, sizeof( int ) );
		    p = lookup(s);
		    putLV( extname , bn , 0 , NNLOCAL , P2PTR | P2CHAR );
		} else {
		    putLV( 0 , bn , -( DPOFF1 + sizeof( int ) ) , LOCALVAR ,
			P2PTR | P2CHAR );
		}
		putop( P2CALL , P2INT );
		putdot( filename , line );
		putleaf( P2ICON , 0 , 0 , ADDTYPE( P2FTN | P2INT , P2PTR )
			, "_longjmp" );
		putLV( 0 , bn , GOTOENVOFFSET , NLOCAL , P2PTR|P2STRTY );
		extlabname( extname , p -> symbol , bn );
		putLV( extname , 0 , 0 , NGLOBAL , P2PTR|P2STRTY );
		putop( P2LISTOP , P2INT );
		putop( P2CALL , P2INT );
		putdot( filename , line );
	    }
#	endif PC
	if (bn == cbn)
		if (p->nl_flags & NFORWD) {
			if (p->value[NL_GOLEV] == NOTYET) {
				p->value[NL_GOLEV] = level;
				p->value[NL_GOLINE] = line;
			}
		} else
			if (p->value[NL_GOLEV] == DEAD) {
				recovered();
				error("Goto %s is into a structured statement", p->symbol);
			}
}

/*
 * Labeled is called when a label
 * definition is encountered, and
 * marks that it has been found and
 * patches the associated GOTO generated
 * by gotoop.
 */
labeled(s)
	char *s;
{
	register struct nl *p;
#ifdef PC
	char	extname[ BUFSIZ ];
#endif PC

	p = lookup(s);
	if (p == NIL)
		return (NIL);
	if (bn != cbn) {
		error("Label %s not defined in correct block", s);
		return;
	}
	if ((p->nl_flags & NFORWD) == 0) {
		error("Label %s redefined", s);
		return;
	}
	p->nl_flags &= ~NFORWD;
#	ifdef OBJ
	    patch4(p->value[NL_ENTLOC]);
#	endif OBJ
#	ifdef PC
	    extlabname( extname , p -> symbol , bn );
	    putprintf( "%s:" , 0 , extname );
#	endif PC
	if (p->value[NL_GOLEV] != NOTYET)
		if (p->value[NL_GOLEV] < level) {
			recovered();
			error("Goto %s from line %d is into a structured statement", s, p->value[NL_GOLINE]);
		}
	p->value[NL_GOLEV] = level;
}
#endif

#ifdef PC
    /*
     *	construct the long name of a label based on it's static nesting.
     *	into a caller-supplied buffer (that should be about BUFSIZ big).
     */
extlabname( buffer , name , level )
    char	buffer[];
    char	*name;
    int		level;
{
    char	*starthere;
    int		i;

    starthere = &buffer[0];
    for ( i = 1 ; i < level ; i++ ) {
	sprintf( starthere , EXTFORMAT , enclosing[ i ] );
	starthere += strlen( enclosing[ i ] ) + 1;
    }
    sprintf( starthere , EXTFORMAT , "" );
    starthere += 1;
    sprintf( starthere , LABELFORMAT , name );
    starthere += strlen( name ) + 1;
    if ( starthere >= &buffer[ BUFSIZ ] ) {
	panic( "extlabname" );
    }
}
#endif PC