Category : C Source Code
Archive   : F2CSRC.ZIP
Filename : EXEC.C

/****************************************************************
Copyright 1990 by AT&T Bell Laboratories and Bellcore.

Permission to use, copy, modify, and distribute this software
and its documentation for any purpose and without fee is hereby
granted, provided that the above copyright notice appear in all
copies and that both that the copyright notice and this
permission notice and warranty disclaimer appear in supporting
documentation, and that the names of AT&T Bell Laboratories or
Bellcore or any of their entities not be used in advertising or
publicity pertaining to distribution of the software without
specific, written prior permission.

AT&T and Bellcore disclaim all warranties with regard to this
software, including all implied warranties of merchantability
and fitness. In no event shall AT&T or Bellcore be liable for
any special, indirect or consequential damages or any damages
whatsoever resulting from loss of use, data or profits, whether
in an action of contract, negligence or other tortious action,
arising out of or in connection with the use or performance of
this software.
****************************************************************/

#include "defs.h"
#include "p1defs.h"
#include "names.h"

LOCAL void exar2(), popctl(), pushctl();

/* Logical IF codes
*/


exif(p)
expptr p;
{
pushctl(CTLIF);
putif(p, 0); /* 0 => if, not elseif */
}



exelif(p)
expptr p;
{
if (ctlstack->ctltype == CTLIF || ctlstack->ctltype == CTLIFX)
putif(p, 1); /* 1 ==> elseif */
else
execerr("elseif out of place", CNULL);
}





exelse()
{
register struct Ctlframe *c;

for(c = ctlstack; c->ctltype == CTLIFX; --c);
if(c->ctltype == CTLIF) {
p1_else ();
c->ctltype = CTLELSE;
}
else
execerr("else out of place", CNULL);
}


exendif()
{
while(ctlstack->ctltype == CTLIFX) {
popctl();
p1else_end();
}
if(ctlstack->ctltype == CTLIF) {
popctl();
p1_endif ();
}
else if(ctlstack->ctltype == CTLELSE) {
popctl();
p1else_end ();
}
else
execerr("endif out of place", CNULL);
}


new_endif()
{
if (ctlstack->ctltype == CTLIF || ctlstack->ctltype == CTLIFX)
pushctl(CTLIFX);
else
err("new_endif bug");
}

/* pushctl -- Start a new control construct, initialize the labels (to
zero) */

LOCAL void
pushctl(code)
int code;
{
register int i;

if(++ctlstack >= lastctl)
many("loops or if-then-elses", 'c', maxctl);
ctlstack->ctltype = code;
for(i = 0 ; i < 4 ; ++i)
ctlstack->ctlabels[i] = 0;
ctlstack->dowhile = 0;
++blklevel;
}


LOCAL void
popctl()
{
if( ctlstack-- < ctls )
Fatal("control stack empty");
--blklevel;
}



/* poplab -- update the flags in labeltab */

LOCAL poplab()
{
register struct Labelblock *lp;

for(lp = labeltab ; lp < highlabtab ; ++lp)
if(lp->labdefined)
{
/* mark all labels in inner blocks unreachable */
if(lp->blklevel > blklevel)
lp->labinacc = YES;
}
else if(lp->blklevel > blklevel)
{
/* move all labels referred to in inner blocks out a level */
lp->blklevel = blklevel;
}
}


/* BRANCHING CODE
*/

exgoto(lab)
struct Labelblock *lab;
{
lab->labused = 1;
p1_goto (lab -> stateno);
}







exequals(lp, rp)
register struct Primblock *lp;
register expptr rp;
{
if(lp->tag != TPRIM)
{
err("assignment to a non-variable");
frexpr((expptr)lp);
frexpr(rp);
}
else if(lp->namep->vclass!=CLVAR && lp->argsp)
{
if(parstate >= INEXEC)
err("statement function amid executables");
mkstfunct(lp, rp);
}
else
{
expptr new_lp, new_rp;

if(parstate < INDATA)
enddcl();
new_lp = mklhs (lp);
new_rp = fixtype (rp);
puteq(new_lp, new_rp);
}
}



/* Make Statement Function */

long laststfcn = -1, thisstno;
int doing_stmtfcn;

mkstfunct(lp, rp)
struct Primblock *lp;
expptr rp;
{
register struct Primblock *p;
register Namep np;
chainp args;

laststfcn = thisstno;
np = lp->namep;
if(np->vclass == CLUNKNOWN)
np->vclass = CLPROC;
else
{
dclerr("redeclaration of statement function", np);
return;
}
np->vprocclass = PSTFUNCT;
np->vstg = STGSTFUNCT;

/* Set the type of the function */

impldcl(np);
if (np->vtype == TYCHAR && !np->vleng)
err("character statement function with length (*)");
args = (lp->argsp ? lp->argsp->listp : CHNULL);
np->varxptr.vstfdesc = mkchain((char *)args, (chainp)rp);

for(doing_stmtfcn = 1 ; args ; args = args->nextp)

/* It is an error for the formal parameters to have arguments or
subscripts */

if( ((tagptr)(args->datap))->tag!=TPRIM ||
(p = (struct Primblock *)(args->datap) )->argsp ||
p->fcharp || p->lcharp )
err("non-variable argument in statement function definition");
else
{

/* Replace the name on the left-hand side */

args->datap = (char *)p->namep;
vardcl(p -> namep);
free((char *)p);
}
doing_stmtfcn = 0;
}

static void
mixed_type(np)
Namep np;
{
char buf[128];
sprintf(buf, "%s function %.90s invoked as subroutine",
ftn_types[np->vtype], np->fvarname);
warn(buf);
}


excall(name, args, nstars, labels)
Namep name;
struct Listblock *args;
int nstars;
struct Labelblock *labels[ ];
{
register expptr p;

if (name->vtype != TYSUBR) {
if (name->vinfproc && !name->vcalled) {
name->vtype = TYSUBR;
frexpr(name->vleng);
name->vleng = 0;
}
else if (!name->vimpltype && name->vtype != TYUNKNOWN)
mixed_type(name);
else
settype(name, TYSUBR, (ftnint)0);
}
p = mkfunct( mkprim(name, args, CHNULL) );

/* Subroutines and their identifiers acquire the type INT */

p->exprblock.vtype = p->exprblock.leftp->headblock.vtype = TYINT;

/* Handle the alternate return mechanism */

if(nstars > 0)
putcmgo(putx(fixtype(p)), nstars, labels);
else
putexpr(p);
}



exstop(stop, p)
int stop;
register expptr p;
{
char *str;
int n;
expptr mkstrcon();

if(p)
{
if( ! ISCONST(p) )
{
execerr("pause/stop argument must be constant", CNULL);
frexpr(p);
p = mkstrcon(0, CNULL);
}
else if( ISINT(p->constblock.vtype) )
{
str = convic(p->constblock.Const.ci);
n = strlen(str);
if(n > 0)
{
p->constblock.Const.ccp = copyn(n, str);
p->constblock.Const.ccp1.blanks = 0;
p->constblock.vtype = TYCHAR;
p->constblock.vleng = (expptr) ICON(n);
}
else
p = (expptr) mkstrcon(0, CNULL);
}
else if(p->constblock.vtype != TYCHAR)
{
execerr("pause/stop argument must be integer or string", CNULL);
p = (expptr) mkstrcon(0, CNULL);
}
}
else p = (expptr) mkstrcon(0, CNULL);

{
expptr subr_call;

subr_call = call1(TYSUBR, (stop ? "s_stop" : "s_paus"), p);
putexpr( subr_call );
}
}

/* DO LOOP CODE */

#define DOINIT par[0]
#define DOLIMIT par[1]
#define DOINCR par[2]


/* Macros for ctlstack -> dostepsign */

#define VARSTEP 0
#define POSSTEP 1
#define NEGSTEP 2


/* exdo -- generate DO loop code. In the case of a variable increment,
positive increment tests are placed above the body, negative increment
tests are placed below (see enddo() ) */

exdo(range, loopname, spec)
int range; /* end label */
Namep loopname;
chainp spec; /* input spec must have at least 2 exprs */
{
register expptr p;
register Namep np;
chainp cp; /* loops over the fields in spec */
register int i;
int dotype; /* type of the index variable */
int incsign; /* sign of the increment, if it's constant
*/
Addrp dovarp; /* loop index variable */
expptr doinit; /* constant or register for init param */
expptr par[3]; /* local specification parameters */

expptr init, test, inc; /* Expressions in the resulting FOR loop */


test = ENULL;

pushctl(CTLDO);
dorange = ctlstack->dolabel = range;
ctlstack->loopname = loopname;

/* Declare the loop index */

np = (Namep)spec->datap;
ctlstack->donamep = NULL;
if (!np) { /* do while */
ctlstack->dowhile = 1;
#if 0
if (loopname) {
if (loopname->vtype == TYUNKNOWN) {
loopname->vdcldone = 1;
loopname->vclass = CLLABEL;
loopname->vprocclass = PLABEL;
loopname->vtype = TYLABEL;
}
if (loopname->vtype == TYLABEL)
if (loopname->vdovar)
dclerr("already in use as a loop name",
loopname);
else
loopname->vdovar = 1;
else
dclerr("already declared; cannot be a loop name",
loopname);
}
#endif
putwhile((expptr)spec->nextp);
NOEXT("do while");
spec->nextp = 0;
frchain(&spec);
return;
}
if(np->vdovar)
{
errstr("nested loops with variable %s", np->fvarname);
ctlstack->donamep = NULL;
return;
}

/* Create a memory-resident version of the index variable */

dovarp = mkplace(np);
if( ! ONEOF(dovarp->vtype, MSKINT|MSKREAL) )
{
err("bad type on do variable");
return;
}
ctlstack->donamep = np;

np->vdovar = YES;

/* Now dovarp points to the index to be used within the loop, dostgp
points to the one which may need to be stored */

dotype = dovarp->vtype;

/* Count the input specifications and type-check each one independently;
this just eliminates non-numeric values from the specification */

for(i=0 , cp = spec->nextp ; cp!=NULL && i<3 ; cp = cp->nextp)
{
p = par[i++] = fixtype((tagptr)cp->datap);
if( ! ONEOF(p->headblock.vtype, MSKINT|MSKREAL) )
{
err("bad type on DO parameter");
return;
}
}

frchain(&spec);
switch(i)
{
case 0:
case 1:
err("too few DO parameters");
return;

default:
err("too many DO parameters");
return;

case 2:
DOINCR = (expptr) ICON(1);

case 3:
break;
}


/* Now all of the local specification fields are set, but their types are
not yet consistent */

/* Declare the loop initialization value, casting it properly and declaring a
register if need be */

if (ISCONST (DOINIT) || !onetripflag)
/* putx added 6-29-89 (mwm), not sure if fixtype is required, but I doubt it
since mkconv is called just before */
doinit = putx (mkconv (dotype, DOINIT));
else {
doinit = (expptr) mktmp(dotype, ENULL);
puteq (cpexpr (doinit), DOINIT);
} /* else */

/* Declare the loop ending value, casting it to the type of the index
variable */

if( ISCONST(DOLIMIT) )
ctlstack->domax = mkconv(dotype, DOLIMIT);
else {
ctlstack->domax = (expptr) mktmp0(dotype, ENULL);
puteq (cpexpr (ctlstack -> domax), DOLIMIT);
} /* else */

/* Declare the loop increment value, casting it to the type of the index
variable */

if( ISCONST(DOINCR) )
{
ctlstack->dostep = mkconv(dotype, DOINCR);
if( (incsign = conssgn(ctlstack->dostep)) == 0)
err("zero DO increment");
ctlstack->dostepsign = (incsign > 0 ? POSSTEP : NEGSTEP);
}
else
{
ctlstack->dostep = (expptr) mktmp0(dotype, ENULL);
ctlstack->dostepsign = VARSTEP;
puteq (cpexpr (ctlstack -> dostep), DOINCR);
}

/* All data is now properly typed and in the ctlstack, except for the
initial value. Assignments of temps have been generated already */

switch (ctlstack -> dostepsign) {
case VARSTEP:
test = mkexpr (OPQUEST, mkexpr (OPLT,
cpexpr (ctlstack -> dostep), ICON(0)),
mkexpr (OPCOLON,
mkexpr (OPGE, cpexpr((expptr)dovarp),
cpexpr (ctlstack -> domax)),
mkexpr (OPLE, cpexpr((expptr)dovarp),
cpexpr (ctlstack -> domax))));
break;
case POSSTEP:
test = mkexpr (OPLE, cpexpr((expptr)dovarp),
cpexpr (ctlstack -> domax));
break;
case NEGSTEP:
test = mkexpr (OPGE, cpexpr((expptr)dovarp),
cpexpr (ctlstack -> domax));
break;
default:
erri ("exdo: bad dostepsign '%d'", ctlstack -> dostepsign);
break;
} /* switch (ctlstack -> dostepsign) */

if (onetripflag)
test = mkexpr (OPOR, test,
mkexpr (OPEQ, cpexpr((expptr)dovarp), cpexpr (doinit)));
init = mkexpr (OPASSIGN, cpexpr((expptr)dovarp), doinit);
inc = mkexpr (OPPLUSEQ, (expptr)dovarp, cpexpr (ctlstack -> dostep));

if (!onetripflag && ISCONST (ctlstack -> domax) && ISCONST (doinit)
&& ctlstack -> dostepsign != VARSTEP) {
expptr tester;

tester = mkexpr (OPMINUS, cpexpr (doinit),
cpexpr (ctlstack -> domax));
if (incsign == conssgn (tester))
warn ("DO range never executed");
frexpr (tester);
} /* if !onetripflag && */

p1_for (init, test, inc);
}

exenddo(np)
Namep np;
{
Namep np1;
int here;
struct Ctlframe *cf;

if( ctlstack < ctls )
Fatal("control stack empty");
here = ctlstack->dolabel;
if (ctlstack->ctltype != CTLDO || here >= 0) {
err("misplaced ENDDO");
return;
}
if (np != ctlstack->loopname) {
if (np1 = ctlstack->loopname)
errstr("expected \"enddo %s\"", np1->fvarname);
else
err("expected unnamed ENDDO");
for(cf = ctls; cf < ctlstack; cf++)
if (cf->ctltype == CTLDO && cf->loopname == np) {
here = cf->dolabel;
break;
}
}
enddo(here);
}


enddo(here)
int here;
{
register struct Ctlframe *q;
Namep np; /* name of the current DO index */
Addrp ap;
register int i;
register expptr e;

/* Many DO's can end at the same statement, so keep looping over all
nested indicies */

while(here == dorange)
{
if(np = ctlstack->donamep)
{
p1for_end ();

/* Now we're done with all of the tests, and the loop has terminated.
Store the index value back in long-term memory */

if(ap = memversion(np))
puteq((expptr)ap, (expptr)mkplace(np));
for(i = 0 ; i < 4 ; ++i)
ctlstack->ctlabels[i] = 0;
deregister(ctlstack->donamep);
ctlstack->donamep->vdovar = NO;
e = ctlstack->dostep;
if (e->tag == TADDR && e->addrblock.istemp)
frtemp((Addrp)e);
else
frexpr(e);
e = ctlstack->domax;
if (e->tag == TADDR && e->addrblock.istemp)
frtemp((Addrp)e);
else
frexpr(e);
}
else if (ctlstack->dowhile)
p1for_end ();

/* Set dorange to the closing label of the next most enclosing DO loop
*/

popctl();
poplab();
dorange = 0;
for(q = ctlstack ; q>=ctls ; --q)
if(q->ctltype == CTLDO)
{
dorange = q->dolabel;
break;
}
}
}

exassign(vname, labelval)
register Namep vname;
struct Labelblock *labelval;
{
Addrp p;
expptr mkaddcon();
register Addrp q;
static char nullstr[] = "";
char *fs;
register chainp cp, cpprev;
register ftnint k, stno;

p = mkplace(vname);
if( ! ONEOF(p->vtype, MSKINT|MSKADDR) ) {
err("noninteger assign variable");
return;
}

/* If the label hasn't been defined, then we do things twice:
* once for an executable stmt label, once for a format
*/

/* code for executable label... */

/* Now store the assigned value in a list associated with this variable.
This will be used later to generate a switch() statement in the C output */

if (!labelval->labdefined || !labelval->fmtstring) {

if (vname -> vis_assigned == 0) {
vname -> varxptr.assigned_values = CHNULL;
vname -> vis_assigned = 1;
}

/* don't duplicate labels... */

stno = labelval->stateno;
cpprev = 0;
for(k = 0, cp = vname->varxptr.assigned_values;
cp; cpprev = cp, cp = cp->nextp, k++)
if ((ftnint)cp->datap == stno)
break;
if (!cp) {
cp = mkchain((char *)stno, CHNULL);
if (cpprev)
cpprev->nextp = cp;
else
vname->varxptr.assigned_values = cp;
labelval->labused = 1;
}
putout(mkexpr(OPASSIGN, (expptr)p, mkintcon(k)));
}

/* Code for FORMAT label... */

fs = labelval->fmtstring;
if (!labelval->labdefined || fs && fs != nullstr) {
extern void fmtname();

if (!fs)
labelval->fmtstring = nullstr;
labelval->fmtlabused = 1;
p = ALLOC(Addrblock);
p->tag = TADDR;
p->vtype = TYCHAR;
p->vstg = STGAUTO;
p->memoffset = ICON(0);
fmtname(vname, p);
q = ALLOC(Addrblock);
q->tag = TADDR;
q->vtype = TYCHAR;
q->vstg = STGAUTO;
q->ntempelt = 1;
q->memoffset = ICON(0);
q->uname_tag = UNAM_IDENT;
sprintf(q->user.ident, "fmt_%ld", labelval->stateno);
putout(mkexpr(OPASSIGN, (expptr)p, (expptr)q));
}

} /* exassign */



exarif(expr, neglab, zerlab, poslab)
expptr expr;
struct Labelblock *neglab, *zerlab, *poslab;
{
register int lm, lz, lp;

lm = neglab->stateno;
lz = zerlab->stateno;
lp = poslab->stateno;
expr = fixtype(expr);

if( ! ONEOF(expr->headblock.vtype, MSKINT|MSKREAL) )
{
err("invalid type of arithmetic if expression");
frexpr(expr);
}
else
{
if (lm == lz && lz == lp)
exgoto (neglab);
else if(lm == lz)
exar2(OPLE, expr, neglab, poslab);
else if(lm == lp)
exar2(OPNE, expr, neglab, zerlab);
else if(lz == lp)
exar2(OPGE, expr, zerlab, neglab);
else {
expptr t;

if (!addressable (expr)) {
t = (expptr) mktmp(expr -> headblock.vtype, ENULL);
expr = mkexpr (OPASSIGN, cpexpr (t), expr);
} else
t = (expptr) cpexpr (expr);

p1_if(putx(fixtype(mkexpr (OPLT, expr, ICON (0)))));
exgoto(neglab);
p1_elif (mkexpr (OPEQ, t, ICON (0)));
exgoto(zerlab);
p1_else ();
exgoto(poslab);
p1else_end ();
} /* else */
}
}



/* exar2 -- Do arithmetic IF for only 2 distinct labels; if !(e.op.0)
goto l2 else goto l1. If this seems backwards, that's because it is,
in order to make the 1 pass algorithm work. */

LOCAL void
exar2(op, e, l1, l2)
int op;
expptr e;
struct Labelblock *l1, *l2;
{
expptr comp;

comp = mkexpr (op, e, ICON (0));
p1_if(putx(fixtype(comp)));
exgoto(l1);
p1_else ();
exgoto(l2);
p1else_end ();
}


/* exreturn -- return the value in p from a SUBROUTINE call -- used to
implement the alternate return mechanism */

exreturn(p)
register expptr p;
{
if(procclass != CLPROC)
warn("RETURN statement in main or block data");
if(p && (proctype!=TYSUBR || procclass!=CLPROC) )
{
err("alternate return in nonsubroutine");
p = 0;
}

if (p || proctype == TYSUBR) {
if (p == ENULL) p = ICON (0);
p = mkconv (TYLONG, fixtype (p));
p1_subr_ret (p);
} /* if p || proctype == TYSUBR */
else
p1_subr_ret((expptr)retslot);
}


exasgoto(labvar)
Namep labvar;
{
register Addrp p;
void p1_asgoto();

p = mkplace(labvar);
if( ! ISINT(p->vtype) )
err("assigned goto variable must be integer");
else {
p1_asgoto (p);
} /* else */
}