ref: ce93c2af0b4aeb2c40a05f2b45c1397b7a2ced23
dir: /mi/flatten.c/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <inttypes.h>
#include <ctype.h>
#include <string.h>
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "util.h"
#include "parse.h"
#include "mi.h"
#include "../config.h"
/* takes a list of nodes, and reduces it (and it's subnodes) to a list
* following these constraints:
* - All nodes are expression nodes
* - Nodes with side effects are root nodes
* - All nodes operate on machine-primitive types and tuples
*/
typedef struct Flattenctx Flattenctx;
struct Flattenctx {
int isglobl;
/* return handling */
Node **stmts;
size_t nstmts;
/* return handling */
int hasenv;
int isbigret;
/* pre/postinc handling */
Node **incqueue;
size_t nqueue;
/* break/continue handling */
Node **loopstep;
size_t nloopstep;
Node **loopexit;
size_t nloopexit;
/* location handling */
Htab *globls;
size_t stksz;
};
static Node *flatten(Flattenctx *s, Node *n);
static Node *rval(Flattenctx *s, Node *n);
static Node *lval(Flattenctx *s, Node *n);
static Node *assign(Flattenctx *s, Node *lhs, Node *rhs);
static void append(Flattenctx *s, Node *n)
{
if (debugopt['F'])
dump(n, stdout);
lappend(&s->stmts, &s->nstmts, n);
}
static void cjmp(Flattenctx *s, Node *cond, Node *iftrue, Node *iffalse)
{
Node *jmp;
jmp = mkexpr(cond->loc, Ocjmp, cond, iftrue, iffalse, NULL);
jmp->expr.type = mktype(cond->loc, Tyvoid);
append(s, jmp);
}
static void jmp(Flattenctx *s, Node *lbl)
{
Node *n;
n = mkexpr(lbl->loc, Ojmp, lbl, NULL);
n->expr.type = mktype(n->loc, Tyvoid);
append(s, n);
}
static Node *asn(Node *a, Node *b)
{
Node *n;
assert(a != NULL && b != NULL);
if (tybase(exprtype(a))->type == Tyvoid)
return a;
n = mkexpr(a->loc, Oasn, a, b, NULL);
n->expr.type = exprtype(a);
return n;
}
static int islbl(Node *n)
{
Node *l;
if (exprop(n) != Olit)
return 0;
l = n->expr.args[0];
return l->type == Nlit && l->lit.littype == Llbl;
}
static Node *temp(Flattenctx *flatten, Node *e)
{
Node *t, *dcl;
assert(e->type == Nexpr);
t = gentemp(e->loc, e->expr.type, &dcl);
return t;
}
static Node *add(Node *a, Node *b)
{
Node *n;
n = mkexpr(a->loc, Oadd, a, b, NULL);
n->expr.type = a->expr.type;
return n;
}
static Node *addk(Node *n, uvlong v)
{
Node *k;
k = mkintlit(n->loc, v);
k->expr.type = exprtype(n);
return add(n, k);
}
static Node *sub(Node *a, Node *b)
{
Node *n;
n = mkexpr(a->loc, Osub, a, b, NULL);
n->expr.type = a->expr.type;
return n;
}
static Node *subk(Node *n, uvlong v)
{
Node *k;
k = mkintlit(n->loc, v);
k->expr.type = exprtype(n);
return sub(n, k);
}
static Node *seqlen(Flattenctx *s, Node *n, Type *ty)
{
Node *r;
if (!ty)
ty = n->expr.type;
if (exprtype(n)->type == Tyarray) {
r = mkexpr(n->loc, Osllen, rval(s, n), NULL);
r->expr.type = ty;
} else if (exprtype(n)->type == Tyslice) {
r = mkexpr(n->loc, Osllen, rval(s, n), NULL);
r->expr.type = ty;
} else {
die("invalid seq type for len");
}
return r;
}
static Node *visit(Flattenctx *s, Node *n)
{
size_t i;
Node *r;
for (i = 0; i < n->expr.nargs; i++)
n->expr.args[i] = rval(s, n->expr.args[i]);
if (opispure[exprop(n)]) {
r = n;
} else {
if (exprtype(n)->type == Tyvoid) {
r = mkexpr(n->loc, Olit, mkvoid(n->loc), NULL);
r->expr.type = mktype(n->loc, Tyvoid);
append(s, n);
} else {
r = temp(s, n);
append(s, asn(r, n));
}
}
return r;
}
static void flattencond(Flattenctx *s, Node *n, Node *ltrue, Node *lfalse)
{
Node **args;
Node *v, *lnext;
args = n->expr.args;
switch (exprop(n)) {
case Oland:
lnext = genlbl(n->loc);
flattencond(s, args[0], lnext, lfalse);
append(s, lnext);
flattencond(s, args[1], ltrue, lfalse);
break;
case Olor:
lnext = genlbl(n->loc);
flattencond(s, args[0], ltrue, lnext);
append(s, lnext);
flattencond(s, args[1], ltrue, lfalse);
break;
case Olnot:
flattencond(s, args[0], lfalse, ltrue);
break;
default:
v = rval(s, n);
cjmp(s, v, ltrue, lfalse);
break;
}
}
/* flattenlifies
* a || b
* to
* if a || b
* t = true
* else
* t = false
* ;;
*/
static Node *flattenlazy(Flattenctx *s, Node *n)
{
Node *r, *t, *u;
Node *ltrue, *lfalse, *ldone;
/* set up temps and labels */
r = temp(s, n);
ltrue = genlbl(n->loc);
lfalse = genlbl(n->loc);
ldone = genlbl(n->loc);
/* flatten the conditional */
flattencond(s, n, ltrue, lfalse);
/* if true */
append(s, ltrue);
u = mkexpr(n->loc, Olit, mkbool(n->loc, 1), NULL);
u->expr.type = mktype(n->loc, Tybool);
t = asn(r, u);
append(s, t);
jmp(s, ldone);
/* if false */
append(s, lfalse);
u = mkexpr(n->loc, Olit, mkbool(n->loc, 0), NULL);
u->expr.type = mktype(n->loc, Tybool);
t = asn(r, u);
append(s, t);
jmp(s, ldone);
/* finish */
append(s, ldone);
return r;
}
static Node *destructure(Flattenctx *s, Node *lhs, Node *rhs)
{
Node *lv, *rv, *idx;
Node **args;
size_t i;
args = lhs->expr.args;
rhs = rval(s, rhs);
for (i = 0; i < lhs->expr.nargs; i++) {
idx = mkintlit(rhs->loc, i);
idx->expr.type = mktype(rhs->loc, Tyuint64);
rv = mkexpr(rhs->loc, Otupget, rhs, idx, NULL);
rv->expr.type = lhs->expr.type;
if (exprop(args[i]) == Otup) {
destructure(s, args[i], rv);
} else {
lv = lval(s, args[i]);
append(s, assign(s, lv, rv));
}
}
return rhs;
}
static Node *comparecomplex(Flattenctx *s, Node *n, Op op)
{
fatal(n, "Complex comparisons not yet supported\n");
return NULL;
}
static Node *compare(Flattenctx *s, Node *n, int fields)
{
const Op cmpmap[Numops][3] = {
[Oeq] = {Oeq, Oueq, Ofeq},
[One] = {One, Oune, Ofne},
[Ogt] = {Ogt, Ougt, Ofgt},
[Oge] = {Oge, Ouge, Ofge},
[Olt] = {Olt, Oult, Oflt},
[Ole] = {Ole, Oule, Ofle}
};
Node *r;
Type *ty;
Op newop;
/* void is always void */
if (tybase(exprtype(n->expr.args[0]))->type == Tyvoid)
return mkboollit(n->loc, 1);
newop = Obad;
ty = tybase(exprtype(n->expr.args[0]));
if (istysigned(ty))
newop = cmpmap[n->expr.op][0];
else if (istyunsigned(ty))
newop = cmpmap[n->expr.op][1];
else if (istyunsigned(ty))
newop = cmpmap[n->expr.op][1];
else if (ty->type == Typtr)
newop = cmpmap[n->expr.op][1];
else if (istyfloat(ty))
newop = cmpmap[n->expr.op][2];
if (newop != Obad) {
n->expr.op = newop;
r = visit(s, n);
} else if (fields) {
r = comparecomplex(s, n, exprop(n));
} else {
fatal(n, "unsupported comparison on values");
}
r->expr.type = mktype(n->loc, Tybool);
return r;
}
static Node *assign(Flattenctx *s, Node *lhs, Node *rhs)
{
Node *r, *t, *u;
if (exprop(lhs) == Otup) {
r = destructure(s, lhs, rhs);
} else if (tybase(exprtype(lhs))->type != Tyvoid) {
t = lval(s, lhs);
u = rval(s, rhs);
r = asn(t, u);
} else {
r = rval(s, rhs);
}
return r;
}
static Node *rval(Flattenctx *s, Node *n)
{
Node *t, *u, *v; /* temporary nodes */
Node *r; /* expression result */
Node **args;
size_t i;
Type *ty;
const Op fusedmap[Numops] = {
[Oaddeq] = Oadd,
[Osubeq] = Osub,
[Omuleq] = Omul,
[Odiveq] = Odiv,
[Omodeq] = Omod,
[Oboreq] = Obor,
[Obandeq] = Oband,
[Obxoreq] = Obxor,
[Obsleq] = Obsl,
[Obsreq] = Obsr,
};
r = NULL;
args = n->expr.args;
switch (exprop(n)) {
case Osize:
r = n; /* don't touch subexprs; they're a pseudo decl */
break;
case Olor: case Oland:
r = flattenlazy(s, n);
break;
case Oidx:
t = rval(s, n->expr.args[0]);
u = rval(s, n->expr.args[1]);
r = mkexpr(n->loc, Oidx, t, u, NULL);
r->expr.type = n->expr.type;
break;
/* array.len slice.len are magic 'virtual' members.
* they need to be special cased. */
case Omemb:
ty = tybase(exprtype(args[0]));
if (ty->type == Tyslice || ty->type == Tyarray) {
r = seqlen(s, args[0], exprtype(n));
} else {
t = rval(s, args[0]);
r = mkexpr(n->loc, Omemb, t, args[1], NULL);
r->expr.type = n->expr.type;
}
break;
case Oucon:
if (n->expr.nargs > 1)
t = rval(s, args[1]);
else
t = NULL;
r = mkexpr(n->loc, Oucon, args[0], t, NULL);
r->expr.type = n->expr.type;
break;
/* fused ops:
* foo ?= blah
* =>
* foo = foo ? blah*/
case Oaddeq: case Osubeq: case Omuleq: case Odiveq: case Omodeq:
case Oboreq: case Obandeq: case Obxoreq: case Obsleq: case Obsreq:
assert(fusedmap[exprop(n)] != Obad);
u = lval(s, args[0]);
v = rval(s, args[1]);
v = mkexpr(n->loc, fusedmap[exprop(n)], u, v, NULL);
v->expr.type = u->expr.type;
r = asn(u, v);
break;
/* ++expr(x)
* => args[0] = args[0] + 1
* expr(x) */
case Opreinc:
t = lval(s, args[0]);
v = asn(t, addk(t, 1));
append(s, v);
r = rval(s, t);
break;
case Opredec:
t = lval(s, args[0]);
v = asn(t, subk(t, 1));
append(s, v);
r = rval(s, t);
break;
/* expr(x++)
* => expr
* x = x + 1
*/
case Opostinc:
r = lval(s, args[0]);
t = asn(r, addk(r, 1));
lappend(&s->incqueue, &s->nqueue, t);
break;
case Opostdec:
r = lval(s, args[0]);
t = asn(r, subk(r, 1));
lappend(&s->incqueue, &s->nqueue, t);
break;
case Olit:
switch (args[0]->lit.littype) {
case Lvoid:
case Lchr:
case Lbool:
case Llbl:
case Lint:
case Lstr:
case Lflt:
case Lfunc:
r = n; //capture(s, n, dst);
break;
}
break;
case Ovar:
r = n;
break;;
case Oret:
/* drain the increment queue before we return */
t = rval(s, args[0]);
for (i = 0; i < s->nqueue; i++)
append(s, s->incqueue[i]);
lfree(&s->incqueue, &s->nqueue);
append(s, mkexpr(n->loc, Oret, t, NULL));
break;
case Oasn:
r = assign(s, args[0], args[1]);
break;
case Obreak:
r = NULL;
if (s->nloopexit == 0)
fatal(n, "trying to break when not in loop");
jmp(s, s->loopexit[s->nloopexit - 1]);
break;
case Ocontinue:
r = NULL;
if (s->nloopstep == 0)
fatal(n, "trying to continue when not in loop");
jmp(s, s->loopstep[s->nloopstep - 1]);
break;
case Oeq: case One:
r = compare(s, n, 1);
break;
case Ogt: case Oge: case Olt: case Ole:
r = compare(s, n, 0);
break;
default:
if (istyfloat(exprtype(n))) {
switch (exprop(n)) {
case Oadd: n->expr.op = Ofadd; break;
case Osub: n->expr.op = Ofsub; break;
case Omul: n->expr.op = Ofmul; break;
case Odiv: n->expr.op = Ofdiv; break;
default: break;
}
}
r = visit(s, n);
break;
}
if (r && n->expr.idx)
r->expr.idx = n->expr.idx;
return r;
}
static Node *lval(Flattenctx *s, Node *n)
{
Node *r;
switch (exprop(n)) {
case Ovar: r = n; break;
case Oidx: r = rval(s, n); break;//loadidx(s, args[0], args[1]); break;
case Oderef: r = rval(s, n); break;
case Omemb: r = rval(s, n); break;
case Ostruct: r = rval(s, n); break;
case Oucon: r = rval(s, n); break;
case Oarr: r = rval(s, n); break;
case Ogap: r = temp(s, n); break;
/* not actually expressible as lvalues in syntax, but we generate them */
case Oudata: r = rval(s, n); break;
case Outag: r = rval(s, n); break;
case Otupget: r = rval(s, n); break;
default:
fatal(n, "%s cannot be an lvalue", opstr[exprop(n)]);
break;
}
return r;
}
static void flattenblk(Flattenctx *fc, Node *n)
{
size_t i;
for (i = 0; i < n->block.nstmts; i++) {
n->block.stmts[i] = fold(n->block.stmts[i], 0);
flatten(fc, n->block.stmts[i]);
}
}
/* init; while cond; body;;
* => init
* jmp :cond
* :body
* ...body...
* ...step...
* :cond
* ...cond...
* cjmp (cond) :body :end
* :end
*/
static void flattenloop(Flattenctx *s, Node *n)
{
Node *lbody;
Node *lend;
Node *lcond;
Node *lstep;
lbody = genlbl(n->loc);
lcond = genlbl(n->loc);
lstep = genlbl(n->loc);
lend = genlbl(n->loc);
lappend(&s->loopstep, &s->nloopstep, lstep);
lappend(&s->loopexit, &s->nloopexit, lend);
flatten(s, n->loopstmt.init); /* init */
jmp(s, lcond); /* goto test */
flatten(s, lbody); /* body lbl */
flatten(s, n->loopstmt.body); /* body */
flatten(s, lstep); /* test lbl */
flatten(s, n->loopstmt.step); /* step */
flatten(s, lcond); /* test lbl */
flattencond(s, n->loopstmt.cond, lbody, lend); /* repeat? */
flatten(s, lend); /* exit */
s->nloopstep--;
s->nloopexit--;
}
/* if foo; bar; else baz;;
* => cjmp (foo) :bar :baz */
static void flattenif(Flattenctx *s, Node *n, Node *exit)
{
Node *l1, *l2, *l3;
Node *iftrue, *iffalse;
l1 = genlbl(n->loc);
l2 = genlbl(n->loc);
if (exit)
l3 = exit;
else
l3 = genlbl(n->loc);
iftrue = n->ifstmt.iftrue;
iffalse = n->ifstmt.iffalse;
flattencond(s, n->ifstmt.cond, l1, l2);
flatten(s, l1);
flatten(s, iftrue);
jmp(s, l3);
flatten(s, l2);
/* because lots of bunched up end labels are ugly,
* coalesce them by handling 'elif'-like constructs
* separately */
if (iffalse && iffalse->type == Nifstmt) {
flattenif(s, iffalse, exit);
} else {
flatten(s, iffalse);
jmp(s, l3);
}
if (!exit)
flatten(s, l3);
}
static void flattenloopmatch(Flattenctx *s, Node *pat, Node *val, Node *ltrue, Node *lfalse)
{
Node **cap, **out, *lload;
size_t i, ncap, nout;
/* pattern match */
lload = genlbl(pat->loc);
out = NULL;
nout = 0;
cap = NULL;
ncap = 0;
genonematch(pat, val, lload, lfalse, &out, &nout, &cap, &ncap);
for (i = 0; i < nout; i++)
flatten(s, out[i]);
flatten(s, lload);
for (i = 0; i < ncap; i++)
flatten(s, cap[i]);
jmp(s, ltrue);
}
/* pat; seq;
* body;;
*
* =>
* .pseudo = seqinit
* jmp :cond
* :body
* ...body...
* :step
* ...step...
* :cond
* ...cond...
* cjmp (cond) :match :end
* :match
* ...match...
* cjmp (match) :load :step
* :load
* matchval = load
* :end
*/
static void flattenidxiter(Flattenctx *s, Node *n)
{
Node *lbody, *lstep, *lcond, *lmatch, *lend;
Node *idx, *len, *dcl, *seq, *val, *done;
Node *zero;
Type *idxtype;
lbody = genlbl(n->loc);
lstep = genlbl(n->loc);
lcond = genlbl(n->loc);
lmatch = genlbl(n->loc);
lend = genlbl(n->loc);
lappend(&s->loopstep, &s->nloopstep, lstep);
lappend(&s->loopexit, &s->nloopexit, lend);
/* FIXME: pass this in from main() */
idxtype = mktype(n->loc, Tyuint64);
zero = mkintlit(n->loc, 0);
zero->expr.type = idxtype;
seq = rval(s, n->iterstmt.seq);
idx = gentemp(n->loc, idxtype, &dcl);
/* setup */
append(s, asn(idx, zero));
jmp(s, lcond);
flatten(s, lbody);
/* body */
flatten(s, n->iterstmt.body);
/* step */
flatten(s, lstep);
flatten(s, asn(idx, addk(idx, 1)));
/* condition */
flatten(s, lcond);
len = seqlen(s, seq, idxtype);
done = mkexpr(n->loc, Olt, idx, len, NULL);
done->expr.type = mktype(n->loc, Tybool);
cjmp(s, done, lmatch, lend);
flatten(s, lmatch);
val = mkexpr(n->loc, Oidx, seq, idx, NULL);
val->expr.type = tybase(exprtype(seq))->sub[0];
/* pattern match */
flattenloopmatch(s, n->iterstmt.elt, val, lbody, lstep);
jmp(s, lbody);
flatten(s, lend);
s->nloopstep--;
s->nloopexit--;
}
static Node *itertraitfn(Srcloc loc, Trait *tr, char *fn, Type *ty)
{
Node *proto, *dcl, *var;
char *name;
size_t i;
for (i = 0; i < tr->nfuncs; i++) {
name = declname(tr->funcs[i]);
if (!strcmp(fn, name)) {
proto = tr->funcs[i];
dcl = htget(proto->decl.impls, ty);
var = mkexpr(loc, Ovar, dcl->decl.name, NULL);
var->expr.type = dcl->decl.type;
var->expr.did = dcl->decl.did;
return var;
}
}
return NULL;
}
/* for pat in seq
* body;;
* =>
* .seq = seq
* .elt = elt
* :body
* ..body..
* :step
* __iterfin__(&seq, &elt)
* cond = __iternext__(&seq, &eltout)
* cjmp (cond) :match :end
* :match
* ...match...
* cjmp (match) :load :step
* :load
* ...load matches...
* :end
*/
static void flattentraititer(Flattenctx *s, Node *n)
{
Node *lbody, *lclean, *lstep, *lmatch, *lend;
Node *done, *val, *iter, *valptr, *iterptr;
Node *func, *call;
Trait *tr;
val = temp(s, n->iterstmt.elt);
valptr = mkexpr(val->loc, Oaddr, val, NULL);
valptr->expr.type = mktyptr(n->loc, exprtype(val));
iter = temp(s, n->iterstmt.seq);
iterptr = mkexpr(val->loc, Oaddr, iter, NULL);
iterptr->expr.type = mktyptr(n->loc, exprtype(iter));
tr = traittab[Tciter];
/* create labels */
lbody = genlbl(n->loc);
lclean = genlbl(n->loc);
lstep = genlbl(n->loc);
lmatch = genlbl(n->loc);
lend = genlbl(n->loc);
lappend(&s->loopstep, &s->nloopstep, lstep);
lappend(&s->loopexit, &s->nloopexit, lend);
append(s, asn(iter, n->iterstmt.seq));
jmp(s, lstep);
flatten(s, lbody);
/* body */
flatten(s, n->iterstmt.body);
flatten(s, lclean);
/* call iterator cleanup */
func = itertraitfn(n->loc, tr, "__iterfin__", exprtype(iter));
call = mkexpr(n->loc, Ocall, func, iterptr, valptr, NULL);
call->expr.type = mktype(n->loc, Tyvoid);
append(s, call);
flatten(s, lstep);
/* call iterator step */
func = itertraitfn(n->loc, tr, "__iternext__", exprtype(iter));
call = mkexpr(n->loc, Ocall, func, iterptr, valptr, NULL);
done = gentemp(n->loc, mktype(n->loc, Tybool), NULL);
call->expr.type = exprtype(done);
append(s, asn(done, call));
cjmp(s, done, lmatch, lend);
/* pattern match */
flatten(s, lmatch);
flattenloopmatch(s, n->iterstmt.elt, val, lbody, lclean);
jmp(s, lbody);
flatten(s, lend);
s->nloopstep--;
s->nloopexit--;
}
static void flatteniter(Flattenctx *s, Node *n)
{
switch (tybase(exprtype(n->iterstmt.seq))->type) {
case Tyarray: flattenidxiter(s, n); break;
case Tyslice: flattenidxiter(s, n); break;
default: flattentraititer(s, n); break;
}
}
static void flattenmatch(Flattenctx *fc, Node *n)
{
Node *val;
Node **match;
size_t i, nmatch;
val = rval(fc, n->matchstmt.val);
match = NULL;
nmatch = 0;
genmatch(n, val, &match, &nmatch);
for (i = 0; i < nmatch; i++)
flatten(fc, match[i]);
}
static void flattenexpr(Flattenctx *fc, Node *n)
{
Node *r;
size_t i;
if (islbl(n)) {
append(fc, n);
return;
}
r = rval(fc, n);
if (r)
append(fc, r);
for (i = 0; i < fc->nqueue; i++)
append(fc, fc->incqueue[i]);
lfree(&fc->incqueue, &fc->nqueue);
}
static Node *flatten(Flattenctx *fc, Node *n)
{
Node *r, *u, *t;
if (!n)
return NULL;
r = NULL;
switch (n->type) {
case Nblock: flattenblk(fc, n); break;
case Nloopstmt: flattenloop(fc, n); break;
case Niterstmt: flatteniter(fc, n); break;
case Nifstmt: flattenif(fc, n, NULL); break;
case Nmatchstmt: flattenmatch(fc, n); break;
case Nexpr: flattenexpr(fc, n); break;
case Ndecl:
append(fc, n);
r = mkexpr(n->loc, Ovar, n->decl.name, NULL);
if (n->decl.init) {
t = rval(fc, n->decl.init);
u = mkexpr(n->loc, Oasn, r, t, NULL);
u->expr.type = n->decl.type;
r->expr.type = n->decl.type;
r->expr.did = n->decl.did;
flatten(fc, u);
}
break;
default:
dump(n, stderr);
die("bad node passsed to flatten()");
break;
}
return r;
}
static Node *flatteninit(Node *dcl)
{
Flattenctx fc = {0,};
Node *lit, *fn, *blk, *body;
lit = dcl->decl.init->expr.args[0];
fn = lit->lit.fnval;
body = fn->func.body;
flatten(&fc, fn->func.body);
blk = mkblock(fn->loc, body->block.scope);
blk->block.stmts = fc.stmts;
blk->block.nstmts = fc.nstmts;
fn->func.body = blk;
return dcl;
}
static int ismain(Node *n)
{
n = n->decl.name;
if (n->name.ns)
return 0;
return strcmp(n->name.name, "main") == 0;
}
Node *flattenfn(Node *dcl)
{
if (ismain(dcl))
dcl->decl.vis = Vishidden;
if (dcl->decl.isextern || dcl->decl.isgeneric)
return dcl;
if (isconstfn(dcl)) {
dcl = flatteninit(dcl);
//lappend(fn, nfn, f);
}
//lappend(fn, nfn, f);
return dcl;
}
int isconstfn(Node *n)
{
Node *d, *e;
Type *t;
if (n->type == Nexpr) {
if (exprop(n) != Ovar)
return 0;
d = decls[n->expr.did];
} else {
d = n;
}
t = tybase(decltype(d));
if (!d || !d->decl.isconst || !d->decl.isglobl || d->decl.isgeneric)
return 0;
if (t->type != Tyfunc && t->type != Tycode)
return 0;
e = d->decl.init;
if (e && (exprop(e) != Olit || e->expr.args[0]->lit.littype != Lfunc))
return 0;
if (!e && !d->decl.isextern && !d->decl.isimport)
return 0;
return 1;
}