1BSD/pi/fdec.c
#
/*
* pi - Pascal interpreter code translator
*
* Charles Haley, Bill Joy UCB
* Version 1.0 August 1977
*/
#include "whoami"
#include "0.h"
#include "tree.h"
#include "opcode.h"
int cntpatch;
int nfppatch;
/*
* Funchdr inserts
* declaration of a the
* prog/proc/func into the
* namelist. It also handles
* the arguments and puts out
* a transfer which defines
* the entry point of a procedure.
*/
funchdr(r)
int *r;
{
register struct nl *p;
register *il, **rl;
int *rll;
struct nl *cp, *dp, *sp;
int o, *pp;
if (inpflist(r[2])) {
opush('l');
yyretrieve(); /* kludge */
}
pfcnt++;
line = r[1];
if (r[3] == NIL && (p=lookup1(r[2])) != NIL && bn == cbn) {
/*
* Symbol already defined
* in this block. it is either
* a redeclared symbol (error)
* or a forward declaration.
*/
if ((p->class == FUNC || p->class == PROC) && (p->nl_flags & NFORWD) != 0) {
/*
* Grammar doesnt forbid
* types on a resolution
* of a forward function
* declaration.
*/
if (p->class == FUNC && r[4])
error("Function type should be given only in forward declaration");
putcnt();
return (p);
}
}
/*
* Declare the prog/proc/func
*/
switch (r[0]) {
case T_PROG:
if (opt('z'))
monflg++;
program = p = defnl(r[2], PROG, 0, 0);
p->value[3] = r[1];
break;
case T_PDEC:
if (r[4] != NIL)
error("Procedures do not have types, only functions do");
p = enter(defnl(r[2], PROC, 0, 0));
p->nl_flags =| NMOD;
break;
case T_FDEC:
il = r[4];
if (il == NIL)
error("Function type must be specified");
else if (il[0] != T_TYID) {
il = NIL;
error("Function type can be specified only by using a type identifier");
} else
il = gtype(il);
p = enter(defnl(r[2], FUNC, il, NIL));
p->nl_flags =| NMOD;
/*
* An arbitrary restriction
*/
switch (o = classify(p->type)) {
case TFILE:
case TARY:
case TREC:
case TSET:
case TSTR:
warning();
if (opt('s'))
standard();
error("Functions should not return %ss", clnames[o]);
}
break;
default:
panic("funchdr");
}
if (r[0] != T_PROG) {
/*
* Mark this proc/func as
* begin forward declared
*/
p->nl_flags =| NFORWD;
/*
* Enter the parameters
* in the next block for
* the time being
*/
if (++cbn >= DSPLYSZ) {
error("Procedure/function nesting too deep");
pexit(ERRS);
}
/*
* For functions, the function variable
*/
if (p->class == FUNC) {
cp = defnl(r[2], FVAR, p->type, 0);
cp->chain = p;
p->value[NL_FVAR] = cp;
}
/*
* Enter the parameters
* and compute total size
*/
cp = sp = p;
o = 0;
for (rl = r[3]; rl != NIL; rl = rl[2]) {
p = NIL;
if (rl[1] == NIL)
continue;
/*
* Parametric procedures
* don't have types !?!
*/
if (rl[1][0] != T_PPROC) {
rll = rl[1][2];
if (rll[0] != T_TYID) {
error("Types for arguments can be specified only by using type identifiers");
p = NIL;
} else
p = gtype(rll);
}
for (il = rl[1][1]; il != NIL; il = il[2]) {
switch (rl[1][0]) {
default:
panic("funchdr2");
case T_PVAL:
if (p != NIL) {
if (p->class == FILE)
error("Files cannot be passed by value");
else if (p->nl_flags & NFILES)
error("Files cannot be a component of %ss passed by value",
nameof(p));
}
dp = defnl(il[1], VAR, p, o=- even(width(p)));
dp->nl_flags =| NMOD;
break;
case T_PVAR:
dp = defnl(il[1], REF, p, o=- 2);
break;
case T_PFUNC:
case T_PPROC:
error("Procedure/function parameters not implemented");
break;
}
if (dp != NIL) {
cp->chain = dp;
cp = dp;
}
}
}
cbn--;
p = sp;
p->value[NL_OFFS] = -o+DPOFF2;
/*
* Correct the naievity
* of our above code to
* calculate offsets
*/
for (il = p->chain; il != NIL; il = il->chain)
il->value[NL_OFFS] =+ p->value[NL_OFFS];
} else {
/*
* The wonderful
* program statement!
*/
if (monflg) {
cntpatch = put2(O_PXPBUF, 0);
nfppatch = put3(NIL, 0, 0);
}
cp = p;
for (rl = r[3]; rl; rl = rl[2]) {
if (rl[1] == NIL)
continue;
dp = defnl(rl[1], VAR, 0, 0);
cp->chain = dp;
cp = dp;
}
}
/*
* Define a branch at
* the "entry point" of
* the prog/proc/func.
*/
p->value[NL_LOC] = getlab();
if (monflg) {
put2(O_TRACNT, p->value[NL_LOC]);
putcnt();
} else
put2(O_TRA, p->value[NL_LOC]);
return (p);
}
funcfwd(fp)
struct nl *fp;
{
return (fp);
}
/*
* Funcbody is called
* when the actual (resolved)
* declaration of a procedure is
* encountered. It puts the names
* of the (function) and parameters
* into the symbol table.
*/
funcbody(fp)
struct nl *fp;
{
register struct nl *q, *p;
cbn++;
if (cbn >= DSPLYSZ) {
error("Too many levels of function/procedure nesting");
pexit(ERRS);
}
sizes[cbn].om_off = 0;
sizes[cbn].om_max = 0;
gotos[cbn] = NIL;
errcnt[cbn] = syneflg;
parts = NIL;
if (fp == NIL)
return (NIL);
/*
* Save the virtual name
* list stack pointer so
* the space can be freed
* later (funcend).
*/
fp->value[2] = nlp;
if (fp->class != PROG)
for (q = fp->chain; q != NIL; q = q->chain)
enter(q);
if (fp->class == FUNC) {
/*
* For functions, enter the fvar
*/
enter(fp->value[NL_FVAR]);
}
return (fp);
}
struct nl *Fp;
int pnumcnt;
/*
* Funcend is called to
* finish a block by generating
* the code for the statements.
* It then looks for unresolved declarations
* of labels, procedures and functions,
* and cleans up the name list.
* For the program, it checks the
* semantics of the program
* statement (yuchh).
*/
funcend(fp, bundle, endline)
struct nl *fp;
int *bundle;
int endline;
{
register struct nl *p;
register int i, b;
int var, inp, out, chkref, *blk;
struct nl *iop;
char *cp;
extern int cntstat;
cntstat = 0;
/*
yyoutline();
*/
if (program != NIL)
line = program->value[3];
blk = bundle[1];
if (fp == NIL) {
cbn--;
return;
}
/*
* Patch the branch to the
* entry point of the function
*/
patch(fp->value[NL_LOC]);
/*
* Put out the block entrance code and the block name.
* the CONG is overlaid by a patch later!
*/
var = put1(cbn == 1 && opt('p') == 0 ? O_NODUMP: O_BEG);
put3(O_CONG, 8, fp->symbol);
put2(NIL, bundle[0]);
if (fp->class == PROG) {
/*
* The glorious buffers option.
* 0 = don't buffer output
* 1 = line buffer output
* 2 = 512 byte buffer output
*/
if (opt('b') != 1)
put1(O_BUFF | opt('b') << 8);
inp = 0;
out = 0;
for (p = fp->chain; p != NIL; p = p->chain) {
if (strcmp(p->symbol, "input") == 0) {
inp++;
continue;
}
if (strcmp(p->symbol, "output") == 0) {
out++;
continue;
}
iop = lookup1(p->symbol);
if (iop == NIL || bn != cbn) {
error("File %s listed in program statement but not declared", p->symbol);
continue;
}
if (iop->class != VAR) {
error("File %s listed in program statement but declared as a %s", p->symbol, classes[iop->class]);
continue;
}
if (iop->type == NIL)
continue;
if (iop->type->class != FILE) {
error("File %s listed in program statement but defined as %s",
p->symbol, nameof(iop->type));
continue;
}
put2(O_LV | bn << 9, iop->value[NL_OFFS]);
b = p->symbol;
while (b->pchar != '\0')
b++;
i = b - p->symbol;
put3(O_CONG, i, p->symbol);
put2(O_DEFNAME | i << 8, text(iop->type) ? 0: width(iop->type->type));
}
if (out == 0 && fp->chain != NIL) {
recovered();
error("The file output must appear in the program statement file list");
}
}
/*
* Process the prog/proc/func body
*/
noreach = 0;
line = bundle[0];
statlist(blk);
if (cbn== 1 && monflg != 0) {
patchfil(cntpatch, cnts);
patchfil(nfppatch, pfcnt);
}
if (fp->class == PROG && inp == 0 && (input->nl_flags & (NUSED|NMOD)) != 0) {
recovered();
error("Input is used but not defined in the program statement");
}
/*
* Clean up the symbol table displays and check for unresolves
*/
line = endline;
b = cbn;
Fp = fp;
chkref = syneflg == errcnt[cbn] && opt('w') == 0;
for (i = 0; i <= 077; i++) {
for (p = disptab[i]; p != NIL && (p->nl_block & 037) == b; p = p->nl_next) {
/*
* Check for variables defined
* but not referenced
*/
if (chkref && p->symbol != NIL)
switch (p->class) {
case FIELD:
/*
* If the corresponding record is
* unused, we shouldn't complain about
* the fields.
*/
default:
if ((p->nl_flags & (NUSED|NMOD)) == 0) {
warning();
nerror("%s %s is neither used nor set", classes[p->class], p->symbol);
break;
}
/*
* If a var parameter is either
* modified or used that is enough.
*/
if (p->class == REF)
continue;
if ((p->nl_flags & NUSED) == 0) {
warning();
nerror("%s %s is never used", classes[p->class], p->symbol);
break;
}
if ((p->nl_flags & NMOD) == 0) {
warning();
nerror("%s %s is used but never set", classes[p->class], p->symbol);
break;
}
case LABEL:
case FVAR:
case BADUSE:
break;
}
switch (p->class) {
case BADUSE:
cp = "s";
if (p->chain->ud_next == NIL)
cp++;
eholdnl();
if (p->value[NL_KINDS] & ISUNDEF)
nerror("%s undefined on line%s", p->symbol, cp);
else
nerror("%s improperly used on line%s", p->symbol, cp);
pnumcnt = 10;
pnums(p->chain);
putchar('\n');
break;
case FUNC:
case PROC:
if (p->nl_flags & NFORWD)
nerror("Unresolved forward declaration of %s %s", classes[p->class], p->symbol);
break;
case LABEL:
if (p->nl_flags & NFORWD)
nerror("label %s was declared but not defined", p->symbol);
break;
case FVAR:
if ((p->nl_flags & NMOD) == 0)
nerror("No assignment to the function variable");
break;
}
}
/*
* Pop this symbol
* table slot
*/
disptab[i] = p;
}
put1(O_END);
#ifdef DEBUG
dumpnl(fp->value[2], fp->symbol);
#endif
/*
* Restore the
* (virtual) name list
* position
*/
nlfree(fp->value[2]);
/*
* Proc/func has been
* resolved
*/
fp->nl_flags =& ~NFORWD;
/*
* Patch the beg
* of the proc/func to
* the proper variable size
*/
i = sizes[cbn].om_max;
if (sizes[cbn].om_max < -50000.)
nerror("Storage requirement of %ld bytes exceeds hardware capacity", -sizes[cbn].om_max);
if (Fp == NIL)
elineon();
patchfil(var, i);
cbn--;
if (inpflist(fp->symbol)) {
opop('l');
}
}
pnums(p)
struct udinfo *p;
{
if (p->ud_next != NIL)
pnums(p->ud_next);
if (pnumcnt == 0) {
printf("\n\t");
pnumcnt = 20;
}
pnumcnt--;
printf(" %d", p->ud_line);
}
nerror(a1, a2, a3)
{
if (Fp != NIL) {
yySsync();
printf("In %s %s:\n", classes[Fp->class], Fp->symbol);
Fp = NIL;
elineoff();
}
error(a1, a2, a3);
}