ref: abad00c11d5e0407b20281cbdae9386c275f4bf5
dir: /parse/infer.c/
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <inttypes.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 <assert.h>
#include "util.h"
#include "parse.h"
static void infernode(Node **np, Type *ret, int *sawret);
static void inferexpr(Node **np, Type *ret, int *sawret);
static void inferdecl(Node *n);
static Type *tf(Type *t);
static Type *unify(Node *ctx, Type *a, Type *b);
static Type *tyfix(Node *ctx, Type *orig, int noerr);
static void typesub(Node *n, int noerr);
/* tracking where we are in the inference */
static int ingeneric;
static int inaggr;
static int indentdepth;
static Srcloc *unifysrc;
static size_t nunifysrc;
/* post-inference checking/unification */
static Htab *delayed;
static Node **postcheck;
static size_t npostcheck;
static Stab **postcheckscope;
static size_t npostcheckscope;
/* generic declarations to be specialized */
static Node **genericdecls;
static size_t ngenericdecls;
static Node **impldecl;
static size_t nimpldecl;
/* specializations of generics */
static Node **specializations;
static size_t nspecializations;
static Stab **specializationscope;
static size_t nspecializationscope;
static Htab *seqbase;
static void
ctxstrcall(char *buf, size_t sz, Node *n)
{
char *p, *end, *sep, *t;
size_t nargs, i;
Node **args;
Type *et;
args = n->expr.args;
nargs = n->expr.nargs;
p = buf;
end = buf + sz;
sep = "";
if (exprop(args[0]) == Ovar)
p += bprintf(p, end - p, "%s(", namestr(args[0]->expr.args[0]));
else
p += bprintf(p, end - p, "<e>(");
for (i = 1; i < nargs; i++) {
et = tyfix(NULL, exprtype(args[i]), 1);
if (et != NULL)
t = tystr(et);
else
t = strdup("?");
if (exprop(args[i]) == Ovar)
p += bprintf(p, end - p, "%s%s:%s", sep, namestr(args[i]->expr.args[0]), t);
else
p += bprintf(p, end - p, "%s<e%zd>:%s", sep, i, t);
sep = ", ";
free(t);
}
if (exprtype(args[0])->nsub)
t = tystr(tyfix(NULL, exprtype(args[0])->sub[0], 1));
else
t = strdup("unknown");
p += bprintf(p, end - p, "): %s", t);
free(t);
}
static char *
nodetystr(Node *n)
{
Type *t;
t = NULL;
if (n->type == Nexpr && exprtype(n) != NULL)
t = tyfix(NULL, exprtype(n), 1);
else if (n->type == Ndecl && decltype(n) != NULL)
t = tyfix(n, decltype(n), 1);
if (t && tybase(t)->type != Tyvar)
return tystr(t);
else
return strdup("unknown");
}
static void
marksrc(Type *t, Srcloc l)
{
t = tf(t);
if (t->tid >= nunifysrc) {
unifysrc = zrealloc(unifysrc, nunifysrc*sizeof(Srcloc), (t->tid + 1)*sizeof(Srcloc));
nunifysrc = t->tid + 1;
}
if (unifysrc[t->tid].line <= 0)
unifysrc[t->tid] = l;
}
static char *
srcstr(Type *ty)
{
char src[128];
Srcloc l;
char *s;
src[0] = 0;
if (nunifysrc > ty->tid && unifysrc[ty->tid].line > 0) {
l = unifysrc[ty->tid];
s = tystr(ty);
snprintf(src, sizeof src, "\n\t%s from %s:%d", s, fname(l), lnum(l));
free(s);
}
return strdup(src);
}
/* Tries to give a good string describing the context
* for the sake of error messages. */
static char *
ctxstr(Node *n)
{
char *t, *t1, *t2, *t3;
char *s, *d;
size_t nargs;
Node **args;
char buf[512];
switch (n->type) {
default: s = strdup(nodestr[n->type]); break;
case Ndecl:
d = declname(n);
t = nodetystr(n);
bprintf(buf, sizeof buf, "%s:%s", d, t);
s = strdup(buf);
free(t);
break;
case Nname: s = strdup(namestr(n)); break;
case Nexpr:
args = n->expr.args;
nargs = n->expr.nargs;
t1 = NULL;
t2 = NULL;
t3 = NULL;
if (exprop(n) == Ovar)
d = namestr(args[0]);
else
d = opstr[exprop(n)];
t = nodetystr(n);
if (nargs >= 1)
t1 = nodetystr(args[0]);
if (nargs >= 2)
t2 = nodetystr(args[1]);
if (nargs >= 3)
t3 = nodetystr(args[2]);
switch (opclass[exprop(n)]) {
case OTpre: bprintf(buf, sizeof buf, "%s<e:%s>", oppretty[exprop(n)], t1); break;
case OTpost: bprintf(buf, sizeof buf, "<e:%s>%s", t1, oppretty[exprop(n)]); break;
case OTzarg: bprintf(buf, sizeof buf, "%s", oppretty[exprop(n)]); break;
case OTbin:
bprintf(buf, sizeof buf, "<e1:%s> %s <e2:%s>", t1, oppretty[exprop(n)], t2);
break;
case OTmisc:
switch (exprop(n)) {
case Ovar: bprintf(buf, sizeof buf, "%s:%s", namestr(args[0]), t); break;
case Ocall: ctxstrcall(buf, sizeof buf,n); break;
case Oidx:
if (exprop(args[0]) == Ovar)
bprintf(buf, sizeof buf, "%s[<e1:%s>]", namestr(args[0]->expr.args[0]), t2);
else
bprintf(buf, sizeof buf, "<sl:%s>[<e1%s>]", t1, t2);
break;
case Oslice:
if (exprop(args[0]) == Ovar)
bprintf(buf, sizeof buf, "%s[<e1:%s>:<e2:%s>]", namestr(args[0]->expr.args[0]), t2, t3);
else
bprintf( buf, sizeof buf, "<sl:%s>[<e1%s>:<e2:%s>]", t1, t2, t3);
break;
case Omemb:
bprintf(buf, sizeof buf, "<%s>.%s", t1, namestr(args[1]));
break;
default:
bprintf(buf, sizeof buf, "%s:%s", d, t);
break;
}
break;
default: bprintf(buf, sizeof buf, "%s", d); break;
}
free(t);
free(t1);
free(t2);
free(t3);
s = strdup(buf);
break;
}
return s;
}
static void
addspecialization(Node *n, Stab *stab)
{
Node *dcl;
dcl = decls[n->expr.did];
lappend(&specializationscope, &nspecializationscope, stab);
lappend(&specializations, &nspecializations, n);
lappend(&genericdecls, &ngenericdecls, dcl);
}
static void
additerspecializations(Node *n, Stab *stab)
{
Trait *tr;
Type *ty;
size_t i;
tr = traittab[Tciter];
ty = exprtype(n->iterstmt.seq);
if (!ty->traits || !bshas(ty->traits, Tciter))
return;
if (ty->type == Tyslice || ty->type == Tyarray || ty->type == Typtr)
return;
for (i = 0; i < tr->nproto; i++) {
ty = exprtype(n->iterstmt.seq);
if (hthas(tr->proto[i]->decl.impls, ty))
continue;
lappend(&specializationscope, &nspecializationscope, stab);
lappend(&specializations, &nspecializations, n);
lappend(&genericdecls, &ngenericdecls, tr->proto[i]);
}
}
static void
delayedcheck(Node *n, Stab *s)
{
lappend(&postcheck, &npostcheck, n);
lappend(&postcheckscope, &npostcheckscope, s);
}
static void
typeerror(Type *a, Type *b, Node *ctx, char *msg)
{
char *t1, *t2, *s1, *s2, *c;
t1 = tystr(tyfix(NULL, a, 1));
t2 = tystr(tyfix(NULL, b, 1));
s1 = srcstr(a);
s2 = srcstr(b);
c = ctxstr(ctx);
if (msg)
fatal(ctx, "type \"%s\" incompatible with \"%s\" near %s: %s%s%s", t1, t2, c, msg, s1, s2);
else
fatal(ctx, "type \"%s\" incompatible with \"%s\" near %s%s%s", t1, t2, c, s1, s2);
free(t1);
free(t2);
free(s1);
free(s2);
free(c);
}
/* Set a scope's enclosing scope up correctly. */
static void
setsuperenv(Tyenv *e, Tyenv *super)
{
Tyenv *te;
/* verify that we don't accidentally create loops */
if (!e)
return;
for (te = super; te; te = te->super)
assert(te->super != e);
e->super = super;
}
/* Set a scope's enclosing scope up correctly. */
static void
setsuper(Stab *st, Stab *super)
{
Stab *s;
/* verify that we don't accidentally create loops */
for (s = super; s; s = s->super)
assert(s->super != st);
st->super = super;
}
/* Checks if a type that directly contains itself.
* Recursive types that contain themselves through
* pointers or slices are fine, but any other self-inclusion
* would lead to a value of infinite size */
static int
occurs_rec(Type *sub, Bitset *bs)
{
size_t i;
if (bshas(bs, sub->tid))
return 1;
bsput(bs, sub->tid);
switch (sub->type) {
case Typtr:
case Tyslice:
break;
case Tystruct:
for (i = 0; i < sub->nmemb; i++)
if (occurs_rec(decltype(sub->sdecls[i]), bs))
return 1;
break;
case Tyunion:
for (i = 0; i < sub->nmemb; i++) {
if (!sub->udecls[i]->etype)
continue;
if (occurs_rec(sub->udecls[i]->etype, bs))
return 1;
}
break;
default:
for (i = 0; i < sub->nsub; i++)
if (occurs_rec(sub->sub[i], bs))
return 1;
break;
}
bsdel(bs, sub->tid);
return 0;
}
static int
occursin(Type *a, Type *b)
{
Bitset *bs;
int r;
bs = mkbs();
bsput(bs, b->tid);
r = occurs_rec(a, bs);
bsfree(bs);
return r;
}
static int
occurs(Type *t)
{
Bitset *bs;
int r;
bs = mkbs();
r = occurs_rec(t, bs);
bsfree(bs);
return r;
}
static int
needfreshenrec(Type *t, Bitset *visited)
{
size_t i;
if (bshas(visited, t->tid))
return 0;
bsput(visited, t->tid);
switch (t->type) {
case Typaram: return 1;
case Tygeneric: return 1;
case Tyname:
for (i = 0; i < t->narg; i++)
if (needfreshenrec(t->arg[i], visited))
return 1;
return needfreshenrec(t->sub[0], visited);
case Tystruct:
for (i = 0; i < t->nmemb; i++)
if (needfreshenrec(decltype(t->sdecls[i]), visited))
return 1;
break;
case Tyunion:
for (i = 0; i < t->nmemb; i++)
if (t->udecls[i]->etype && needfreshenrec(t->udecls[i]->etype, visited))
return 1;
break;
default:
for (i = 0; i < t->nsub; i++)
if (needfreshenrec(t->sub[i], visited))
return 1;
break;
}
return 0;
}
static int
needfreshen(Type *t)
{
Bitset *visited;
int ret;
visited = mkbs();
ret = needfreshenrec(t, visited);
bsfree(visited);
return ret;
}
/* Freshens the type of a declaration. */
static Type *
tyfreshen(Tysubst *subst, Type *orig)
{
Type *t;
if (!needfreshen(orig))
return orig;
pushenv(orig->env);
if (!subst) {
subst = mksubst();
t = tyspecialize(orig, subst, delayed, seqbase);
substfree(subst);
} else {
t = tyspecialize(orig, subst, delayed, seqbase);
}
popenv(orig->env);
return t;
}
/* Resolves a type and all its subtypes recursively. */
static void
tyresolve(Type *t)
{
size_t i;
Type *base;
if (t->resolved)
return;
/* type resolution should never throw errors about non-generic
* showing up within a generic type, so we push and pop a generic
* around resolution */
ingeneric++;
t->resolved = 1;
/* Walk through aggregate type members */
pushenv(t->env);
switch (t->type) {
case Tystruct:
inaggr++;
for (i = 0; i < t->nmemb; i++)
infernode(&t->sdecls[i], NULL, NULL);
inaggr--;
break;
case Tyunion:
inaggr++;
for (i = 0; i < t->nmemb; i++) {
t->udecls[i]->utype = t;
t->udecls[i]->utype = tf(t->udecls[i]->utype);
if (t->udecls[i]->etype) {
tyresolve(t->udecls[i]->etype);
t->udecls[i]->etype = tf(t->udecls[i]->etype);
}
}
inaggr--;
break;
case Tyarray:
if (!inaggr && !t->asize)
lfatal(t->loc, "unsized array type outside of struct");
infernode(&t->asize, NULL, NULL);
break;
case Typaram:
if (!isbound(t))
lfatal(t->loc, "type parameter %s is undefined in generic context", tystr(t));
break;
default:
break;
}
for (i = 0; i < t->nsub; i++)
t->sub[i] = tf(t->sub[i]);
base = tybase(t);
/* no-ops if base == t */
if (t->traits && base->traits)
bsunion(t->traits, base->traits);
else if (base->traits)
t->traits = bsdup(base->traits);
if (occurs(t))
lfatal(t->loc, "type %s includes itself", tystr(t));
popenv(t->env);
ingeneric--;
}
Type *
tysearch(Type *t)
{
if (!t)
return t;
while (tytab[t->tid])
t = tytab[t->tid];
return t;
}
/* Look up the best type to date in the unification table, returning it */
static Type *
tylookup(Type *t)
{
Type *lu;
Stab *ns;
assert(t != NULL);
lu = NULL;
while (1) {
if (!tytab[t->tid] && t->type == Tyunres) {
ns = curstab();
if (t->name->name.ns)
ns = getns(file, t->name->name.ns);
if (!ns)
fatal(t->name, "no namespace \"%s\"", t->name->name.ns);
lu = gettype(ns, t->name);
if (!lu)
fatal(t->name, "no type %s", tystr(t));
if (lu && lu != t)
tytab[t->tid] = lu;
}
if (!tytab[t->tid])
break;
/* compress paths: shift the link up one level */
if (tytab[tytab[t->tid]->tid])
tytab[t->tid] = tytab[tytab[t->tid]->tid];
t = tytab[t->tid];
}
return t;
}
static Type *
tysubstmap(Tysubst *subst, Type *t, Type *orig)
{
size_t i;
for (i = 0; i < t->ngparam; i++) {
substput(subst, t->gparam[i], tf(orig->arg[i]));
}
t = tyfreshen(subst, t);
return t;
}
static Type *
tysubst(Type *t, Type *orig)
{
Tysubst *subst;
subst = mksubst();
t = tysubstmap(subst, t, orig);
substfree(subst);
return t;
}
/* find the most accurate type mapping we have (ie,
* the end of the unification chain */
static Type *
tf(Type *orig)
{
int isgeneric;
Type *t;
assert(orig != NULL);
t = tylookup(orig);
isgeneric = t->type == Tygeneric;
ingeneric += isgeneric;
tyresolve(t);
/* If this is an instantiation of a generic type, we want the params to
* match the instantiation */
if (orig->type == Tyunres && t->type == Tygeneric) {
if (t->ngparam != orig->narg) {
lfatal(orig->loc, "%s incompatibly specialized with %s, declared on %s:%d",
tystr(orig), tystr(t), file->file.files[t->loc.file], t->loc.line);
}
pushenv(orig->env);
t = tysubst(t, orig);
popenv(orig->env);
}
ingeneric -= isgeneric;
return t;
}
/* set the type of any typable node */
static void
settype(Node *n, Type *t)
{
t = tf(t);
switch (n->type) {
case Nexpr: n->expr.type = t; break;
case Ndecl: n->decl.type = t; break;
case Nlit: n->lit.type = t; break;
case Nfunc: n->func.type = t; break;
default: die("untypable node %s", nodestr[n->type]); break;
}
if (t->type != Tyvar)
marksrc(t, n->loc);
}
/* Gets the type of a literal value */
static Type *
littype(Node *n)
{
Type *t;
t = NULL;
if (!n->lit.type) {
switch (n->lit.littype) {
case Lvoid: t = mktype(n->loc, Tyvoid); break;
case Lchr: t = mktype(n->loc, Tychar); break;
case Lbool: t = mktype(n->loc, Tybool); break;
case Lint: t = mktylike(n->loc, Tyint); break;
case Lflt: t = mktylike(n->loc, Tyflt64); break;
case Lstr: t = mktyslice(n->loc, mktype(n->loc, Tybyte)); break;
case Llbl: t = mktyptr(n->loc, mktype(n->loc, Tyvoid)); break;
case Lfunc: t = n->lit.fnval->func.type; break;
}
n->lit.type = t;
}
return n->lit.type;
}
static Type *
delayeducon(Type *fallback)
{
Type *t;
char *from, *to;
if (fallback->type != Tyunion)
return fallback;
t = mktylike(fallback->loc, fallback->type);
htput(delayed, t, fallback);
if (debugopt['u']) {
from = tystr(t);
to = tystr(fallback);
indentf(indentdepth, "Delay %s -> %s\n", from, to);
free(from);
free(to);
}
return t;
}
/* Finds the type of any typable node */
static Type *
type(Node *n)
{
Type *t;
switch (n->type) {
case Nlit: t = littype(n); break;
case Nexpr: t = n->expr.type; break;
case Ndecl: t = decltype(n); break;
case Nfunc: t = n->func.type; break;
default:
t = NULL;
die("untypeable node %s", nodestr[n->type]);
break;
};
return tf(t);
}
static Ucon *
uconresolve(Node *n)
{
Ucon *uc;
Node **args;
Stab *ns;
args = n->expr.args;
ns = curstab();
if (args[0]->name.ns)
ns = getns(file, args[0]->name.ns);
if (!ns)
fatal(n, "no namespace %s\n", args[0]->name.ns);
uc = getucon(ns, args[0]);
if (!uc)
fatal(n, "no union constructor `%s", ctxstr(args[0]));
if (!uc->etype && n->expr.nargs > 1)
fatal(n, "nullary union constructor `%s passed arg ", ctxstr(args[0]));
else if (uc->etype && n->expr.nargs != 2)
fatal(n, "union constructor `%s needs arg ", ctxstr(args[0]));
return uc;
}
/* Binds the type parameters in the
* declaration into the type environment */
void
_bind(Tyenv *e, Node *n)
{
assert(n->type == Ndecl);
if(!n->decl.isgeneric)
return;
ingeneric++;
bindtype(e, n->decl.type);
if (n->decl.init)
bindtype(e, n->decl.init->expr.type);
}
/* Constrains a type to implement the required constraints. On
* type variables, the constraint is added to the required
* constraint list. Otherwise, the type is checked to see
* if it has the required constraint */
static void
constrain(Node *ctx, Type *a, Trait *c)
{
if (a->type == Tyvar) {
if (!a->traits)
a->traits = mkbs();
settrait(a, c);
} else if (!a->traits || !bshas(a->traits, c->uid)) {
fatal(ctx, "%s needs %s near %s", tystr(a), namestr(c->name), ctxstr(ctx));
}
}
static int
satisfiestraits(Type *a, Type *b)
{
if (!a->traits || bscount(a->traits) == 0)
return 1;
return bsissubset(a->traits, b->traits);
}
static void
verifytraits(Node *ctx, Type *a, Type *b)
{
size_t i, n;
Srcloc l;
char *sep;
char traitbuf[64], abuf[64], bbuf[64];
char asrc[64], bsrc[64];
if (!satisfiestraits(a, b)) {
sep = "";
n = 0;
for (i = 0; bsiter(a->traits, &i); i++) {
if (!b->traits || !bshas(b->traits, i))
n += bprintf(traitbuf + n, sizeof(traitbuf) - n, "%s%s", sep,
namestr(traittab[i]->name));
sep = ",";
}
tyfmt(abuf, sizeof abuf, a);
tyfmt(bbuf, sizeof bbuf, b);
bsrc[0] = 0;
if (nunifysrc > b->tid && unifysrc[b->tid].line > 0) {
l = unifysrc[b->tid];
snprintf(bsrc, sizeof asrc, "\n\t%s from %s:%d", bbuf, fname(l), lnum(l));
}
fatal(ctx, "%s missing traits %s for %s near %s%s%s",
bbuf, traitbuf, abuf, ctxstr(ctx),
srcstr(a), srcstr(b));
}
}
/* Merges the constraints on types */
static void
mergetraits(Node *ctx, Type *a, Type *b)
{
if (b->type == Tyvar) {
/* make sure that if a = b, both have same traits */
if (a->traits && b->traits)
bsunion(b->traits, a->traits);
else if (a->traits)
b->traits = bsdup(a->traits);
else if (b->traits)
a->traits = bsdup(b->traits);
} else {
verifytraits(ctx, a, b);
}
}
/* Computes the 'rank' of the type; ie, in which
* direction should we unify. A lower ranked type
* should be mapped to the higher ranked (ie, more
* specific) type. */
static int
tyrank(Type *t)
{
if (t->type == Tyvar) {
/* has associated iterator type */
if (hthas(seqbase, t))
return 1;
else
return 0;
}
return 2;
}
static void
unionunify(Node *ctx, Type *u, Type *v)
{
size_t i, j;
int found;
if (u->nmemb != v->nmemb)
fatal(ctx, "can't unify %s and %s near %s%s%s\n",
tystr(u), tystr(v), ctxstr(ctx),
srcstr(u), srcstr(v));
for (i = 0; i < u->nmemb; i++) {
found = 0;
for (j = 0; j < v->nmemb; j++) {
if (!nameeq(u->udecls[i]->name, v->udecls[j]->name))
continue;
found = 1;
if (u->udecls[i]->etype == NULL && v->udecls[j]->etype == NULL)
continue;
else if (u->udecls[i]->etype && v->udecls[j]->etype)
unify(ctx, u->udecls[i]->etype, v->udecls[j]->etype);
else
fatal(ctx, "can't unify %s and %s near %s%s%s",
tystr(u), tystr(v), ctxstr(ctx),
srcstr(u), srcstr(v));
}
if (!found)
fatal(ctx, "can't unify %s and %s near %s%s%s",
tystr(u), tystr(v), ctxstr(ctx),
srcstr(u), srcstr(v));
}
}
static void
structunify(Node *ctx, Type *u, Type *v)
{
size_t i, j;
int found;
char *ud, *vd;
if (u->nmemb != v->nmemb)
fatal(ctx, "can't unify %s and %s near %s%s%s",
tystr(u), tystr(v), ctxstr(ctx),
srcstr(u), srcstr(v));
for (i = 0; i < u->nmemb; i++) {
found = 0;
for (j = 0; j < v->nmemb; j++) {
ud = namestr(u->sdecls[i]->decl.name);
vd = namestr(v->sdecls[j]->decl.name);
if (strcmp(ud, vd) == 0) {
found = 1;
unify(ctx, type(u->sdecls[i]), type(v->sdecls[j]));
}
}
/* we had at least one missing member */
if (!found)
fatal(ctx, "can't unify %s and %s near %s%s%s",
tystr(u), tystr(v), ctxstr(ctx),
srcstr(u), srcstr(v));
}
}
static void
membunify(Node *ctx, Type *u, Type *v)
{
if (hthas(delayed, u))
u = htget(delayed, u);
u = tybase(u);
if (hthas(delayed, v))
v = htget(delayed, v);
v = tybase(v);
if (u->type == Tyunion && v->type == Tyunion && u != v)
unionunify(ctx, u, v);
else if (u->type == Tystruct && v->type == Tystruct && u != v)
structunify(ctx, u, v);
}
static Type *
basetype(Type *a)
{
Type *t;
t = htget(seqbase, a);
while (!t && a->type == Tyname) {
a = a->sub[0];
t = htget(seqbase, a);
}
if (!t && (a->type == Tyslice || a->type == Tyarray || a->type == Typtr))
t = a->sub[0];
if (t)
t = tf(t);
return t;
}
static void
checksize(Node *ctx, Type *a, Type *b)
{
if (a->asize)
a->asize = fold(a->asize, 1);
if (b->asize)
b->asize = fold(b->asize, 1);
if (a->asize && exprop(a->asize) != Olit)
lfatal(ctx->loc, "%s: array size is not constant near %s",
tystr(a), ctxstr(ctx));
if (b->asize && exprop(b->asize) != Olit)
lfatal(ctx->loc, "%s: array size is not constant near %s",
tystr(b), ctxstr(ctx));
if (!a->asize)
a->asize = b->asize;
else if (!b->asize)
b->asize = a->asize;
else if (a->asize && b->asize)
if (!litvaleq(a->asize->expr.args[0], b->asize->expr.args[0]))
lfatal(ctx->loc, "array size of %s does not match %s near %s",
tystr(a), tystr(b), ctxstr(ctx));
}
static int
hasargs(Type *t)
{
return t->type == Tyname && t->narg > 0;
}
/* Unifies two types, or errors if the types are not unifiable. */
static Type *
unify(Node *ctx, Type *u, Type *v)
{
Type *t, *r;
Type *a, *b;
Type *ea, *eb;
char *from, *to;
size_t i;
/* a ==> b */
a = tf(u);
b = tf(v);
if (a->tid == b->tid)
return a;
/* we unify from lower to higher ranked types */
if (tyrank(b) < tyrank(a)) {
t = a;
a = b;
b = t;
}
if (debugopt['u']) {
from = tystr(a);
to = tystr(b);
indentf(indentdepth, "Unify %s => %s\n", from, to);
indentf(indentdepth + 1, "indexes: %s => %s\n",
tystr(htget(seqbase, a)), tystr(htget(seqbase, b)));
free(from);
free(to);
}
/* Disallow recursive types */
if (a->type == Tyvar && b->type != Tyvar) {
if (occursin(a, b))
fatal(ctx, "%s occurs within %s, leading to infinite type near %s\n",
tystr(a), tystr(b), ctxstr(ctx));
}
r = NULL;
if (a->type == Tyvar || tyeq(a, b)) {
tytab[a->tid] = b;
if (ctx) {
marksrc(a, ctx->loc);
marksrc(b, ctx->loc);
}
}
if (a->type == Tyvar) {
ea = basetype(a);
eb = basetype(b);
if (ea && eb)
unify(ctx, ea, eb);
r = b;
}
if (a->type == Tyarray && b->type == Tyarray) {
checksize(ctx, a, b);
}
/* if the tyrank of a is 0 (ie, a raw tyvar), just unify.
* Otherwise, match up subtypes. */
if (a->type == b->type && a->type != Tyvar) {
if (a->type == Tyname)
if (!nameeq(a->name, b->name))
typeerror(a, b, ctx, "incompatible types");
if (hasargs(a) && hasargs(b)) {
/* Only Tygeneric and Tyname should be able to unify. And they
* should have the same names for this to be true. */
if (!nameeq(a->name, b->name))
typeerror(a, b, ctx, NULL);
if (a->narg != b->narg)
typeerror(a, b, ctx, "incompatible parameter lists");
for (i = 0; i < a->narg; i++)
unify(ctx, a->arg[i], b->arg[i]);
r = b;
}
if (a->nsub != b->nsub) {
verifytraits(ctx, a, b);
if (tybase(a)->type == Tyfunc)
typeerror(a, b, ctx, "function arity mismatch");
else
typeerror(a, b, ctx, "subtype counts incompatible");
}
for (i = 0; i < b->nsub; i++)
unify(ctx, a->sub[i], b->sub[i]);
r = b;
} else if (a->type != Tyvar) {
typeerror(a, b, ctx, NULL);
}
mergetraits(ctx, a, b);
if (a->isreflect || b->isreflect) {
tagreflect(r);
tagreflect(a);
tagreflect(b);
}
membunify(ctx, a, b);
/* if we have delayed types for a tyvar, transfer it over. */
if (a->type == Tyvar && b->type == Tyvar) {
if (hthas(delayed, a) && !hthas(delayed, b))
htput(delayed, b, htget(delayed, a));
else if (hthas(delayed, b) && !hthas(delayed, a))
htput(delayed, a, htget(delayed, b));
} else if (hthas(delayed, a)) {
unify(ctx, htget(delayed, a), tybase(b));
}
return r;
}
/* Applies unifications to function calls.
* Funciton application requires a slightly
* different approach to unification. */
static void
unifycall(Node *n)
{
size_t i;
Type *ft;
char *ret, *ctx;
ft = type(n->expr.args[0]);
if (ft->type == Tyvar) {
/* the first arg is the function itself, so it shouldn't be counted */
ft = mktyfunc(n->loc, &n->expr.args[1], n->expr.nargs - 1, mktyvar(n->loc));
unify(n, ft, type(n->expr.args[0]));
} else if (tybase(ft)->type != Tyfunc) {
fatal(n, "calling uncallable type %s", tystr(ft));
}
/* first arg: function itself */
for (i = 1; i < n->expr.nargs; i++) {
if (i == ft->nsub)
fatal(n, "%s arity mismatch (expected %zd args, got %zd)",
ctxstr(n->expr.args[0]), ft->nsub - 1, n->expr.nargs - 1);
if (ft->sub[i]->type == Tyvalist) {
break;
}
unify(n->expr.args[0], ft->sub[i], type(n->expr.args[i]));
}
if (i < ft->nsub && ft->sub[i]->type != Tyvalist)
fatal(n, "%s arity mismatch (expected %zd args, got %zd)",
ctxstr(n->expr.args[0]), ft->nsub - 1, i - 1);
if (debugopt['u']) {
ret = tystr(ft->sub[0]);
ctx = ctxstr(n->expr.args[0]);
indentf(indentdepth, "Call of %s returns %s\n", ctx, ret);
free(ctx);
free(ret);
}
settype(n, ft->sub[0]);
}
static void
unifyparams(Node *ctx, Type *a, Type *b)
{
size_t i;
/* The only types with unifiable params are Tyunres and Tyname.
* Tygeneric should always be freshened, and no other types have
* parameters attached.
*
* FIXME: Is it possible to have parameterized typarams? */
if (a->type != Tyunres && a->type != Tyname)
return;
if (b->type != Tyunres && b->type != Tyname)
return;
if (a->narg != b->narg)
fatal(ctx, "mismatched arg list sizes: %s with %s near %s", tystr(a), tystr(b),
ctxstr(ctx));
for (i = 0; i < a->narg; i++)
unify(ctx, a->arg[i], b->arg[i]);
}
static void
loaduses(Node *n)
{
size_t i;
/* uses only allowed at top level. Do we want to keep it this way? */
for (i = 0; i < n->file.nuses; i++)
readuse(n->file.uses[i], n->file.globls, Visintern);
}
static Type *
initvar(Node *n, Node *s)
{
Type *t, *param;
Tysubst *subst;
if (s->decl.ishidden)
fatal(n, "attempting to refer to hidden decl %s", ctxstr(n));
param = n->expr.param;
if (s->decl.isgeneric) {
subst = mksubst();
if (param)
substput(subst, s->decl.trait->param, param);
pushenv(s->decl.env);
t = tysubstmap(subst, tf(s->decl.type), s->decl.type);
popenv(s->decl.env);
if (s->decl.trait && !param) {
param = substget(subst, s->decl.trait->param);
if (!param)
fatal(n, "ambiguous trait decl %s", ctxstr(s));
}
substfree(subst);
} else {
t = s->decl.type;
}
n->expr.did = s->decl.did;
n->expr.isconst = s->decl.isconst;
if (param) {
n->expr.param = param;
delayedcheck(n, curstab());
}
if (s->decl.isgeneric && !ingeneric) {
t = tyfreshen(NULL, t);
addspecialization(n, curstab());
if (t->type == Tyvar) {
settype(n, mktyvar(n->loc));
delayedcheck(n, curstab());
} else {
settype(n, t);
}
} else {
settype(n, t);
}
return t;
}
/* Finds out if the member reference is actually
* referring to a namespaced name, instead of a struct
* member. If it is, it transforms it into the variable
* reference we should have, instead of the Omemb expr
* that we do have */
static Node *
checkns(Node *n, Node **ret)
{
Node *var, *name, *nsname;
Node **args;
Stab *stab;
Node *s;
/* check that this is a namespaced declaration */
if (n->type != Nexpr)
return n;
if (exprop(n) != Omemb)
return n;
if (!n->expr.nargs)
return n;
args = n->expr.args;
if (args[0]->type != Nexpr || exprop(args[0]) != Ovar)
return n;
name = args[0]->expr.args[0];
stab = getns(file, namestr(name));
if (!stab)
return n;
/* substitute the namespaced name */
nsname = mknsname(n->loc, namestr(name), namestr(args[1]));
s = getdcl(stab, args[1]);
if (!s)
fatal(n, "undeclared var %s.%s", nsname->name.ns, nsname->name.name);
var = mkexpr(n->loc, Ovar, nsname, NULL);
var->expr.idx = n->expr.idx;
initvar(var, s);
*ret = var;
return var;
}
static void
inferstruct(Node *n, int *isconst)
{
size_t i;
*isconst = 1;
/* we want to check outer nodes before inner nodes when unifying nested structs */
delayedcheck(n, curstab());
for (i = 0; i < n->expr.nargs; i++) {
infernode(&n->expr.args[i], NULL, NULL);
if (!n->expr.args[i]->expr.isconst)
*isconst = 0;
}
settype(n, mktyvar(n->loc));
}
static int64_t
arraysize(Node *n)
{
int64_t sz, off, i;
Node **args, *idx;
sz = 0;
args = n->expr.args;
for (i = 0; i < n->expr.nargs; i++) {
if (args[i]->expr.idx) {
args[i]->expr.idx = fold(args[i]->expr.idx, 1);
idx = args[i]->expr.idx;
if (exprop(idx) != Olit)
fatal(idx, "nonconstant array initializer index near %s\n",
ctxstr(idx));
if (idx->expr.args[0]->lit.littype == Lchr)
off = idx->expr.args[0]->lit.chrval;
else if (idx->expr.args[0]->lit.littype == Lint)
off = idx->expr.args[0]->lit.intval;
else
fatal(idx, "noninteger array initializer index near %s\n",
ctxstr(idx));
if (off >= sz)
sz = off + 1;
} else {
sz++;
}
}
return sz;
}
static void
inferarray(Node *n, int *isconst)
{
size_t i;
Type *t;
Node *len;
*isconst = 1;
len = mkintlit(n->loc, arraysize(n));
t = mktyarray(n->loc, mktyvar(n->loc), len);
for (i = 0; i < n->expr.nargs; i++) {
infernode(&n->expr.args[i], NULL, NULL);
unify(n, t->sub[0], type(n->expr.args[i]));
if (!n->expr.args[i]->expr.isconst)
*isconst = 0;
}
settype(n, t);
}
static void
infertuple(Node *n, int *isconst)
{
Type **types;
size_t i;
*isconst = 1;
types = xalloc(sizeof(Type *) * n->expr.nargs);
for (i = 0; i < n->expr.nargs; i++) {
infernode(&n->expr.args[i], NULL, NULL);
n->expr.isconst = n->expr.isconst && n->expr.args[i]->expr.isconst;
types[i] = type(n->expr.args[i]);
}
*isconst = n->expr.isconst;
settype(n, mktytuple(n->loc, types, n->expr.nargs));
}
static void
inferucon(Node *n, int *isconst)
{
Ucon *uc;
Type *t;
*isconst = 1;
uc = uconresolve(n);
/* Hackety hack hack.
* the types in a generic union may be bound from the tyname that
* defined it, which is not accessible here.
*
* To make it compile, for now, we just bind the types in here.
*/
//tybindall(uc->utype);
t = tysubst(tf(uc->utype), uc->utype);
uc = tybase(t)->udecls[uc->id];
if (uc->etype) {
inferexpr(&n->expr.args[1], NULL, NULL);
unify(n, uc->etype, type(n->expr.args[1]));
*isconst = n->expr.args[1]->expr.isconst;
}
settype(n, delayeducon(t));
//tyunbind();
}
static void
inferpat(Node **np, Node *val, Node ***bind, size_t *nbind)
{
size_t i;
Node **args;
Node *s, *n;
Stab *ns;
Type *t;
n = *np;
n = checkns(n, np);
args = n->expr.args;
for (i = 0; i < n->expr.nargs; i++)
if (args[i]->type == Nexpr)
inferpat(&args[i], val, bind, nbind);
switch (exprop(n)) {
case Otup:
case Ostruct:
case Oarr:
case Olit:
case Omemb:
infernode(np, NULL, NULL);
break;
/* arithmetic expressions just need to be constant */
case Oneg:
case Oadd:
case Osub:
case Omul:
case Odiv:
case Obsl:
case Obsr:
case Oband:
case Obor:
case Obxor:
case Obnot:
infernode(np, NULL, NULL);
if (!n->expr.isconst)
fatal(n, "matching against non-constant expression near %s", ctxstr(n));
break;
case Oucon:
inferucon(n, &n->expr.isconst);
break;
case Ovar:
ns = curstab();
if (args[0]->name.ns)
ns = getns(file, args[0]->name.ns);
s = getdcl(ns, args[0]);
if (s && !s->decl.ishidden) {
if (s->decl.isgeneric)
t = tysubst(s->decl.type, s->decl.type);
else if (s->decl.isconst)
t = s->decl.type;
else
fatal(n, "pattern shadows variable declared on %s:%d near %s",
fname(s->loc), lnum(s->loc), ctxstr(s));
} else {
t = mktyvar(n->loc);
s = mkdecl(n->loc, n->expr.args[0], t);
s->decl.init = val;
settype(n, t);
lappend(bind, nbind, s);
}
settype(n, t);
n->expr.did = s->decl.did;
n->expr.isconst = s->decl.isconst;
break;
case Oaddr:
infernode(np, NULL, NULL);
break;
case Ogap:
infernode(np, NULL, NULL); break;
default: fatal(n, "invalid pattern"); break;
}
}
void
addbindings(Node *n, Node **bind, size_t nbind)
{
size_t i;
/* order of binding shouldn't matter, so push them into the block
* in reverse order. */
for (i = 0; i < nbind; i++) {
putdcl(n->block.scope, bind[i]);
linsert(&n->block.stmts, &n->block.nstmts, 0, bind[i]);
}
}
static void
infersub(Node *n, Type *ret, int *sawret, int *exprconst)
{
Node **args;
size_t i, nargs;
int isconst;
/* Ovar has no subexpressions */
if (exprop(n) == Ovar)
return;
args = n->expr.args;
nargs = n->expr.nargs;
isconst = 1;
for (i = 0; i < nargs; i++) {
/* Nlit, Nvar, etc should not be inferred as exprs */
if (args[i]->type == Nexpr) {
/* Omemb can sometimes resolve to a namespace. We have to check
* this. Icky. */
checkns(args[i], &args[i]);
inferexpr(&args[i], ret, sawret);
isconst = isconst && args[i]->expr.isconst;
}
}
if (opispure[exprop(n)])
n->expr.isconst = isconst;
*exprconst = n->expr.isconst;
}
static void
inferexpr(Node **np, Type *ret, int *sawret)
{
Node **args;
size_t i, nargs;
Node *s, *n;
Type *t, *b;
int isconst;
Stab *ns;
n = *np;
assert(n->type == Nexpr);
args = n->expr.args;
nargs = n->expr.nargs;
infernode(&n->expr.idx, NULL, NULL);
n = checkns(n, np);
switch (exprop(n)) {
/* all operands are same type */
case Oadd: /* @a + @a -> @a */
case Osub: /* @a - @a -> @a */
case Omul: /* @a * @a -> @a */
case Odiv: /* @a / @a -> @a */
case Oneg: /* -@a -> @a */
case Oaddeq: /* @a += @a -> @a */
case Osubeq: /* @a -= @a -> @a */
case Omuleq: /* @a *= @a -> @a */
case Odiveq: /* @a /= @a -> @a */
infersub(n, ret, sawret, &isconst);
t = type(args[0]);
constrain(n, type(args[0]), traittab[Tcnum]);
isconst = args[0]->expr.isconst;
for (i = 1; i < nargs; i++) {
isconst = isconst && args[i]->expr.isconst;
t = unify(n, t, type(args[i]));
}
n->expr.isconst = isconst;
settype(n, t);
break;
case Omod: /* @a % @a -> @a */
case Obor: /* @a | @a -> @a */
case Oband: /* @a & @a -> @a */
case Obxor: /* @a ^ @a -> @a */
case Obsl: /* @a << @a -> @a */
case Obsr: /* @a >> @a -> @a */
case Obnot: /* ~@a -> @a */
case Opreinc: /* ++@a -> @a */
case Opredec: /* --@a -> @a */
case Opostinc: /* @a++ -> @a */
case Opostdec: /* @a-- -> @a */
case Omodeq: /* @a %= @a -> @a */
case Oboreq: /* @a |= @a -> @a */
case Obandeq: /* @a &= @a -> @a */
case Obxoreq: /* @a ^= @a -> @a */
case Obsleq: /* @a <<= @a -> @a */
case Obsreq: /* @a >>= @a -> @a */
infersub(n, ret, sawret, &isconst);
t = type(args[0]);
constrain(n, type(args[0]), traittab[Tcnum]);
constrain(n, type(args[0]), traittab[Tcint]);
isconst = args[0]->expr.isconst;
for (i = 1; i < nargs; i++) {
isconst = isconst && args[i]->expr.isconst;
t = unify(n, t, type(args[i]));
}
n->expr.isconst = isconst;
settype(n, t);
break;
case Oasn: /* @a = @a -> @a */
infersub(n, ret, sawret, &isconst);
t = type(args[0]);
for (i = 1; i < nargs; i++)
t = unify(n, t, type(args[i]));
settype(n, t);
if (args[0]->expr.isconst)
fatal(n, "attempting to assign constant \"%s\"", ctxstr(args[0]));
break;
/* operands same type, returning bool */
case Olor: /* @a || @b -> bool */
case Oland: /* @a && @b -> bool */
case Oeq: /* @a == @a -> bool */
case One: /* @a != @a -> bool */
case Ogt: /* @a > @a -> bool */
case Oge: /* @a >= @a -> bool */
case Olt: /* @a < @a -> bool */
case Ole: /* @a <= @b -> bool */
infersub(n, ret, sawret, &isconst);
t = type(args[0]);
for (i = 1; i < nargs; i++)
unify(n, t, type(args[i]));
settype(n, mktype(Zloc, Tybool));
break;
case Olnot: /* !bool -> bool */
infersub(n, ret, sawret, &isconst);
t = unify(n, type(args[0]), mktype(Zloc, Tybool));
settype(n, t);
break;
/* reach into a type and pull out subtypes */
case Oaddr: /* &@a -> @a* */
infersub(n, ret, sawret, &isconst);
settype(n, mktyptr(n->loc, type(args[0])));
break;
case Oderef: /* @a# -> @a */
infersub(n, ret, sawret, &isconst);
t = unify(n, type(args[0]), mktyptr(n->loc, mktyvar(n->loc)));
settype(n, t->sub[0]);
break;
case Oidx: /* @a[@b::tcint] -> @a */
infersub(n, ret, sawret, &isconst);
b = mktyvar(n->loc);
t = mktyvar(n->loc);
htput(seqbase, t, b);
unify(n, type(args[0]), t);
constrain(n, type(args[0]), traittab[Tcidx]);
constrain(n, type(args[1]), traittab[Tcint]);
settype(n, b);
break;
case Oslice: /* @a[@b::tcint,@b::tcint] -> @a[,] */
infersub(n, ret, sawret, &isconst);
b = mktyvar(n->loc);
t = mktyvar(n->loc);
htput(seqbase, t, b);
unify(n, type(args[0]), t);
constrain(n, type(args[1]), traittab[Tcint]);
constrain(n, type(args[2]), traittab[Tcint]);
settype(n, mktyslice(n->loc, b));
break;
/* special cases */
case Omemb: /* @a.Ident -> @b, verify type(@a.Ident)==@b later */
infersub(n, ret, sawret, &isconst);
settype(n, mktyvar(n->loc));
delayedcheck(n, curstab());
break;
case Osize: /* sizeof(@a) -> size */
infersub(n, ret, sawret, &isconst);
settype(n, mktylike(n->loc, Tyuint));
break;
case Ocall: /* (@a, @b, @c, ... -> @r)(@a, @b, @c, ...) -> @r */
infersub(n, ret, sawret, &isconst);
unifycall(n);
break;
case Ocast: /* (@a : @b) -> @b */
infersub(n, ret, sawret, &isconst);
delayedcheck(n, curstab());
break;
case Oret: /* -> @a -> void */
infersub(n, ret, sawret, &isconst);
if (sawret)
*sawret = 1;
if (!ret)
fatal(n, "returns are not valid near %s", ctxstr(n));
t = unify(n, ret, type(args[0]));
settype(n, t);
break;
case Obreak:
case Ocontinue:
/* nullary: nothing to infer. */
settype(n, mktype(Zloc, Tyvoid));
break;
case Ojmp: /* goto void* -> void */
if (args[0]->type == Nlit && args[0]->lit.littype == Llbl)
args[0] = getlbl(curstab(), args[0]->loc, args[0]->lit.lblname);
infersub(n, ret, sawret, &isconst);
settype(n, mktype(Zloc, Tyvoid));
break;
case Ovar: /* a:@a -> @a */
infersub(n, ret, sawret, &isconst);
/* if we created this from a namespaced var, the type should be
* set, and the normal lookup is expected to fail. Since we're
* already done with this node, we can just return. */
if (n->expr.type)
return;
ns = curstab();
if (args[0]->name.ns)
ns = getns(file, args[0]->name.ns);
s = getdcl(ns, args[0]);
if (!s)
fatal(n, "undeclared var %s", ctxstr(args[0]));
if (n->expr.param && !s->decl.trait)
fatal(n, "var %s must refer to a trait decl", ctxstr(args[0]));
initvar(n, s);
break;
case Ogap: /* _ -> @a */
if (n->expr.type)
return;
n->expr.type = mktyvar(n->loc);
break;
case Oucon: inferucon(n, &n->expr.isconst); break;
case Otup: infertuple(n, &n->expr.isconst); break;
case Ostruct: inferstruct(n, &n->expr.isconst); break;
case Oarr: inferarray(n, &n->expr.isconst); break;
case Olit: /* <lit>:@a::tyclass -> @a */
infersub(n, ret, sawret, &isconst);
switch (args[0]->lit.littype) {
case Lfunc:
//tybindall(args[0]->lit.fnval->func.type);
infernode(&args[0]->lit.fnval, NULL, NULL);
//tyunbind();
/* FIXME: env capture means this is non-const */
n->expr.isconst = 1;
break;
case Llbl:
s = getlbl(curstab(), args[0]->loc, args[0]->lit.lblname);
if (!s)
fatal(n, "unable to find label %s in function scope\n", args[0]->lit.lblname);
*np = s;
break;
default:
n->expr.isconst = 1;
break;
}
settype(n, type(args[0]));
break;
case Oundef:
infersub(n, ret, sawret, &isconst);
settype(n, mktype(n->loc, Tyvoid));
break;
case Odef:
case Odead:
n->expr.type = mktype(n->loc, Tyvoid);
break;
/* unexpected in frontend */
case Obad:
case Ocjmp:
case Ovjmp:
case Oset:
case Oslbase:
case Osllen:
case Outag:
case Ocallind:
case Oblit:
case Oclear:
case Oudata:
case Otrunc:
case Oswiden:
case Ozwiden:
case Oint2flt:
case Oflt2int:
case Oflt2flt:
case Ofadd:
case Ofsub:
case Ofmul:
case Ofdiv:
case Ofneg:
case Ofeq:
case Ofne:
case Ofgt:
case Ofge:
case Oflt:
case Ofle:
case Oueq:
case Oune:
case Ougt:
case Ouge:
case Oult:
case Oule:
case Otupget:
case Numops:
die("Should not see %s in fe", opstr[exprop(n)]);
break;
}
}
static void
inferfunc(Node *n)
{
size_t i;
int sawret;
sawret = 0;
for (i = 0; i < n->func.nargs; i++)
infernode(&n->func.args[i], NULL, NULL);
infernode(&n->func.body, n->func.type->sub[0], &sawret);
/* if there's no return stmt in the function, assume void ret */
if (!sawret)
unify(n, type(n)->sub[0], mktype(Zloc, Tyvoid));
}
static void
specializeimpl(Node *n)
{
Node *dcl, *proto, *name, *sym;
Tysubst *subst;
Type *ty;
Trait *t;
size_t i, j;
t = gettrait(curstab(), n->impl.traitname);
if (!t)
fatal(n, "no trait %s\n", namestr(n->impl.traitname));
n->impl.trait = t;
dcl = NULL;
if (n->impl.naux != t->naux)
fatal(n, "%s incompatibly specialized with %zd types instead of %zd types",
namestr(n->impl.traitname), n->impl.naux, t->naux);
n->impl.type = tf(n->impl.type);
pushenv(n->impl.type->env);
for (i = 0; i < n->impl.naux; i++)
n->impl.aux[i] = tf(n->impl.aux[i]);
for (i = 0; i < n->impl.ndecls; i++) {
/* look up the prototype */
proto = NULL;
dcl = n->impl.decls[i];
/*
since the decls in an impl are not installed in a namespace,
their names are not updated when we call updatens() on the
symbol table. Because we need to do namespace dependent
comparisons for specializing, we need to set the namespace
here.
*/
if (file->file.globls->name)
setns(dcl->decl.name, file->file.globls->name);
for (j = 0; j < t->nproto; j++) {
if (nsnameeq(dcl->decl.name, t->proto[j]->decl.name)) {
proto = t->proto[j];
break;
}
}
if (!proto)
fatal(n, "declaration %s missing in %s, near %s", namestr(dcl->decl.name),
namestr(t->name), ctxstr(n));
/* infer and unify types */
verifytraits(n, t->param, n->impl.type);
subst = mksubst();
substput(subst, t->param, n->impl.type);
for (j = 0; j < t->naux; j++)
substput(subst, t->aux[j], n->impl.aux[j]);
ty = tyspecialize(type(proto), subst, delayed, NULL);
substfree(subst);
inferdecl(dcl);
unify(n, type(dcl), ty);
/* and put the specialization into the global stab */
name = genericname(proto, n->impl.type, ty);
sym = getdcl(file->file.globls, name);
if (sym)
fatal(n, "trait %s already specialized with %s on %s:%d",
namestr(t->name), tystr(n->impl.type),
fname(sym->loc), lnum(sym->loc));
dcl->decl.name = name;
putdcl(file->file.globls, dcl);
htput(proto->decl.impls, n->impl.type, dcl);
dcl->decl.isconst = 1;
if (ty->type == Tygeneric || hasparams(ty)) {
dcl->decl.isgeneric = 1;
lappend(&proto->decl.gimpl, &proto->decl.ngimpl, dcl);
lappend(&proto->decl.gtype, &proto->decl.ngtype, ty);
}
if (debugopt['S'])
printf("specializing trait [%d]%s:%s => %s:%s\n", n->loc.line,
namestr(proto->decl.name), tystr(type(proto)), namestr(name),
tystr(ty));
dcl->decl.vis = t->vis;
lappend(&impldecl, &nimpldecl, dcl);
}
popenv(n->impl.type->env);
}
static void
inferdecl(Node *n)
{
Type *t;
t = tf(decltype(n));
if (t->type == Tygeneric && !n->decl.isgeneric) {
t = tyfreshen(NULL, t);
unifyparams(n, t, decltype(n));
}
settype(n, t);
if (n->decl.init) {
inferexpr(&n->decl.init, NULL, NULL);
unify(n, type(n), type(n->decl.init));
if (n->decl.isconst && !n->decl.init->expr.isconst)
fatal(n, "non-const initializer for \"%s\"", ctxstr(n));
}
}
static void
inferstab(Stab *s)
{
void **k;
size_t n, i;
Node *dcl;
Type *t;
void *se;
k = htkeys(s->dcl, &n);
se = curenv();
for (i = 0; i < n; i++) {
dcl = htget(s->dcl, k[i]);
pushenv(dcl->decl.env);
tf(type(dcl));
popenv(dcl->decl.env);
assert(se == curenv());
}
free(k);
k = htkeys(s->ty, &n);
for (i = 0; i < n; i++) {
t = gettype(s, k[i]);
if (!t)
fatal(k[i], "undefined type %s", namestr(k[i]));
t = tysearch(t);
if (t->env)
setsuperenv(t->env, curenv());
pushenv(t->env);
tyresolve(t);
popenv(t->env);
updatetype(s, k[i], t);
}
free(k);
}
static void
infernode(Node **np, Type *ret, int *sawret)
{
size_t i, nbound;
Node **bound, *n, *pat;
Type *t, *b;
n = *np;
if (!n)
return;
if (n->inferred)
return;
n->inferred = 1;
switch (n->type) {
case Nfile:
pushstab(n->file.globls);
inferstab(n->file.globls);
for (i = 0; i < n->file.nstmts; i++)
infernode(&n->file.stmts[i], NULL, sawret);
popstab();
break;
case Ndecl:
if (debugopt['u'])
indentf(indentdepth, "--- infer %s ---\n", declname(n));
if (n->decl.isgeneric)
ingeneric++;
indentdepth++;
setsuperenv(n->decl.env, curenv());
pushenv(n->decl.env);
inferdecl(n);
if (type(n)->type == Typaram && !ingeneric)
fatal(n, "generic type %s in non-generic near %s", tystr(type(n)),
ctxstr(n));
popenv(n->decl.env);
indentdepth--;
if (debugopt['u'])
indentf(indentdepth, "--- done ---\n");
if (n->decl.isgeneric)
ingeneric--;
break;
case Nblock:
setsuper(n->block.scope, curstab());
pushstab(n->block.scope);
inferstab(n->block.scope);
for (i = 0; i < n->block.nstmts; i++)
infernode(&n->block.stmts[i], ret, sawret);
popstab();
break;
case Nifstmt:
infernode(&n->ifstmt.cond, NULL, sawret);
infernode(&n->ifstmt.iftrue, ret, sawret);
infernode(&n->ifstmt.iffalse, ret, sawret);
unify(n, type(n->ifstmt.cond), mktype(n->loc, Tybool));
break;
case Nloopstmt:
setsuper(n->loopstmt.scope, curstab());
pushstab(n->loopstmt.scope);
infernode(&n->loopstmt.init, ret, sawret);
infernode(&n->loopstmt.cond, NULL, sawret);
infernode(&n->loopstmt.step, ret, sawret);
infernode(&n->loopstmt.body, ret, sawret);
unify(n, type(n->loopstmt.cond), mktype(n->loc, Tybool));
popstab();
break;
case Niterstmt:
bound = NULL;
nbound = 0;
inferpat(&n->iterstmt.elt, NULL, &bound, &nbound);
addbindings(n->iterstmt.body, bound, nbound);
infernode(&n->iterstmt.seq, NULL, sawret);
infernode(&n->iterstmt.body, ret, sawret);
b = mktyvar(n->loc);
t = mktyvar(n->loc);
htput(seqbase, t, b);
constrain(n, type(n->iterstmt.seq), traittab[Tciter]);
unify(n, type(n->iterstmt.seq), t);
unify(n, type(n->iterstmt.elt), b);
break;
case Nmatchstmt:
infernode(&n->matchstmt.val, NULL, sawret);
for (i = 0; i < n->matchstmt.nmatches; i++) {
infernode(&n->matchstmt.matches[i], ret, sawret);
pat = n->matchstmt.matches[i]->match.pat;
unify(pat, type(n->matchstmt.val),
type(n->matchstmt.matches[i]->match.pat));
}
break;
case Nmatch:
bound = NULL;
nbound = 0;
inferpat(&n->match.pat, NULL, &bound, &nbound);
addbindings(n->match.block, bound, nbound);
infernode(&n->match.block, ret, sawret);
break;
case Nexpr:
inferexpr(np, ret, sawret);
break;
case Nfunc:
setsuper(n->func.scope, curstab());
pushstab(n->func.scope);
setsuperenv(n->func.env, curenv());
pushenv(n->func.env);
inferstab(n->func.scope);
inferfunc(n);
popenv(n->func.env);
popstab();
break;
case Nimpl:
specializeimpl(n);
break;
case Nlit:
case Nname:
case Nuse:
break;
case Nnone:
die("Nnone should not be seen as node type!");
break;
}
}
/* returns the final type for t, after all unification
* and default constraint selections */
static Type *
tyfix(Node *ctx, Type *orig, int noerr)
{
static Type *tyint, *tyflt;
Type *t, *d, *base;
char *from, *to;
size_t i;
char buf[1024];
if (!tyint)
tyint = mktype(Zloc, Tyint);
if (!tyflt)
tyflt = mktype(Zloc, Tyflt64);
t = tysearch(tf(orig));
base = htget(seqbase, orig);
if (orig->type == Tyvar && hthas(delayed, orig)) {
d = htget(delayed, orig);
if (t->type == Tyvar) {
/* tyvar is guaranteed to unify error-free */
unify(ctx, t, d);
t = tf(t);
} else if (tybase(t)->type != d->type && !noerr) {
fatal(ctx, "type %s not compatible with %s near %s\n", tystr(t),
tystr(d), ctxstr(ctx));
}
}
if (t->type == Tyvar) {
if (hastrait(t, traittab[Tcint]) && satisfiestraits(t, tyint))
t = tyint;
if (hastrait(t, traittab[Tcfloat]) && satisfiestraits(t, tyflt))
t = tyflt;
} else if (!t->fixed) {
t->fixed = 1;
if (t->type == Tyarray) {
typesub(t->asize, noerr);
} else if (t->type == Tystruct) {
inaggr++;
for (i = 0; i < t->nmemb; i++)
typesub(t->sdecls[i], noerr);
inaggr--;
} else if (t->type == Tyunion) {
for (i = 0; i < t->nmemb; i++) {
if (t->udecls[i]->etype) {
tyresolve(t->udecls[i]->etype);
t->udecls[i]->etype =
tyfix(ctx, t->udecls[i]->etype, noerr);
}
}
} else if (t->type == Tyname) {
for (i = 0; i < t->narg; i++)
t->arg[i] = tyfix(ctx, t->arg[i], noerr);
}
for (i = 0; i < t->nsub; i++)
t->sub[i] = tyfix(ctx, t->sub[i], noerr);
}
if (t->type == Tyvar && !noerr) {
if (debugopt['T'])
dump(file, stdout);
fatal(ctx, "underconstrained type %s near %s", tyfmt(buf, 1024, t), ctxstr(ctx));
}
if (debugopt['u'] && !tyeq(orig, t)) {
from = tystr(orig);
to = tystr(t);
indentf(indentdepth, "subst %s => %s\n", from, to);
free(from);
free(to);
}
if (base)
htput(seqbase, t, base);
return t;
}
static void
checkcast(Node *n, Node ***rem, size_t *nrem, Stab ***remscope, size_t *nremscope)
{
/* FIXME: actually verify the casts. Right now, it's ok to leave thi
* unimplemented because bad casts get caught by the backend. */
}
static void
infercompn(Node *n, Node ***rem, size_t *nrem, Stab ***remscope, size_t *nremscope)
{
Node *aggr;
Node *memb;
Node **nl;
Type *t;
size_t i;
int found;
aggr = n->expr.args[0];
memb = n->expr.args[1];
found = 0;
t = tybase(tf(type(aggr)));
/* all array-like types have a fake "len" member that we emulate */
if (t->type == Tyslice || t->type == Tyarray) {
if (!strcmp(namestr(memb), "len")) {
constrain(n, type(n), traittab[Tcnum]);
constrain(n, type(n), traittab[Tcint]);
found = 1;
}
/*
* otherwise, we search aggregate types for the member, and unify
* the expression with the member type; ie:
*
* x: aggrtype y : memb in aggrtype
* ---------------------------------------
* x.y : membtype
*/
} else {
if (tybase(t)->type == Typtr)
t = tybase(tf(t->sub[0]));
if (tybase(t)->type == Tyvar) {
if (!rem)
fatal(n, "underspecified type defined on %s:%d used near %s",
fname(t->loc), lnum(t->loc), ctxstr(n));
lappend(rem, nrem, n);
lappend(remscope, nremscope, curstab());
return;
} else if (tybase(t)->type != Tystruct) {
fatal(n, "type %s does not support member operators near %s",
tystr(t), ctxstr(n));
}
nl = t->sdecls;
for (i = 0; i < t->nmemb; i++) {
if (!strcmp(namestr(memb), declname(nl[i]))) {
unify(n, type(n), decltype(nl[i]));
found = 1;
break;
}
}
}
if (!found)
fatal(aggr, "type %s has no member \"%s\" near %s", tystr(type(aggr)),
ctxstr(memb), ctxstr(aggr));
}
static void
checkstruct(Node *n, Node ***rem, size_t *nrem, Stab ***remscope, size_t *nremscope)
{
Type *t, *et;
Node *val, *name;
size_t i, j;
t = tybase(tf(n->lit.type));
/*
* If we haven't inferred the type, and it's inside another struct,
* we'll eventually get to it.
*
* If, on the other hand, it is genuinely underspecified, we'll give
* a better error on it later.
*/
if (t->type == Tyvar)
return;
if (t->type != Tystruct)
fatal(n, "struct literal is used as non struct type %s", tystr(n->lit.type));
for (i = 0; i < n->expr.nargs; i++) {
val = n->expr.args[i];
name = val->expr.idx;
et = NULL;
for (j = 0; j < t->nmemb; j++) {
if (!strcmp(namestr(t->sdecls[j]->decl.name), namestr(name))) {
et = type(t->sdecls[j]);
break;
}
}
if (!et) {
if (rem) {
lappend(rem, nrem, n);
lappend(remscope, nremscope, curstab());
return;
} else {
fatal(n, "could not find member %s in struct %s, near %s",
namestr(name), tystr(t), ctxstr(n));
}
}
unify(val, et, type(val));
}
}
static void
checkvar(Node *n, Node ***rem, size_t *nrem, Stab ***remscope, size_t *nremscope)
{
Node *proto, *dcl;
Type *ty;
proto = decls[n->expr.did];
ty = NULL;
dcl = NULL;
if (n->expr.param)
dcl = htget(proto->decl.impls, tf(n->expr.param));
if (dcl)
ty = dcl->decl.type;
if (!ty)
ty = tyfreshen(NULL, type(proto));
unify(n, type(n), ty);
}
static void
postcheckpass(Node ***rem, size_t *nrem, Stab ***remscope, size_t *nremscope)
{
size_t i;
Node *n;
for (i = 0; i < npostcheck; i++) {
n = postcheck[i];
pushstab(postcheckscope[i]);
switch (exprop(n)) {
case Omemb: infercompn(n, rem, nrem, remscope, nremscope); break;
case Ocast: checkcast(n, rem, nrem, remscope, nremscope); break;
case Ostruct: checkstruct(n, rem, nrem, remscope, nremscope); break;
case Ovar: checkvar(n, rem, nrem, remscope, nremscope); break;
default: die("should not see %s in postcheck\n", opstr[exprop(n)]);
}
popstab();
}
}
static void
postinfer(void)
{
size_t nrem, nremscope;
Stab **remscope;
Node **rem;
while (1) {
remscope = NULL;
nremscope = 0;
rem = NULL;
nrem = 0;
postcheckpass(&rem, &nrem, &remscope, &nremscope);
if (nrem == npostcheck) {
break;
}
postcheck = rem;
npostcheck = nrem;
postcheckscope = remscope;
npostcheckscope = nremscope;
}
postcheckpass(NULL, NULL, NULL, NULL);
}
/* After inference, replace all
* types in symbol tables with
* the final computed types */
static void
stabsub(Stab *s)
{
void **k;
size_t n, i;
Type *t;
Node *d;
char *dt;
k = htkeys(s->ty, &n);
for (i = 0; i < n; i++) {
t = tysearch(gettype(s, k[i]));
updatetype(s, k[i], t);
tyfix(k[i], t, 0);
}
free(k);
k = htkeys(s->dcl, &n);
for (i = 0; i < n; i++) {
d = getdcl(s, k[i]);
pushenv(d->decl.env);
d->decl.type = tyfix(d, d->decl.type, 0);
popenv(d->decl.env);
if (!d->decl.isconst && !d->decl.isgeneric)
continue;
if (d->decl.trait)
continue;
dt = "const";
if (d->decl.isgeneric)
dt = "generic";
if (!d->decl.isimport && !d->decl.isextern && !d->decl.init)
fatal(d, "non-extern %s \"%s\" has no initializer", dt, ctxstr(d));
}
free(k);
}
static void
checkrange(Node *n)
{
Type *t;
int64_t sval;
uint64_t uval;
static const int64_t svranges[][2] = {
/* signed ints */
[Tyint8] = {-128LL, 127LL}, [Tyint16] = {-32768LL, 32767LL},
/* FIXME: this has been doubled allow for uints... */
[Tyint32] = {-2147483648LL, 2 * 2147483647LL},
[Tyint] = {-2147483648LL, 2 * 2147483647LL},
[Tyint64] = {-9223372036854775808ULL, 9223372036854775807LL},
};
static const uint64_t uvranges[][2] = {
[Tybyte] = {0, 255ULL}, [Tyuint8] = {0, 255ULL}, [Tyuint16] = {0, 65535ULL},
[Tyuint32] = {0, 4294967295ULL}, [Tyuint64] = {0, 18446744073709551615ULL},
[Tychar] = {0, 4294967295ULL},
};
/* signed types */
t = type(n);
if (t->type >= Tyint8 && t->type <= Tyint64) {
sval = n->lit.intval;
if (sval < svranges[t->type][0] || sval > svranges[t->type][1])
fatal(n, "literal value %lld out of range for type \"%s\"", sval, tystr(t));
} else if ((t->type >= Tybyte && t->type <= Tyint64) || t->type == Tychar) {
uval = n->lit.intval;
if (uval < uvranges[t->type][0] || uval > uvranges[t->type][1])
fatal(n, "literal value %llu out of range for type \"%s\"", uval, tystr(t));
}
}
static int
initcompatible(Type *t)
{
if (t->type != Tyfunc)
return 0;
if (t->nsub != 1)
return 0;
if (tybase(t->sub[0])->type != Tyvoid)
return 0;
return 1;
}
static int
maincompatible(Type *t)
{
if (t->nsub > 2)
return 0;
if (tybase(t->sub[0])->type != Tyvoid)
return 0;
if (t->nsub == 2) {
t = tybase(t->sub[1]);
if (t->type != Tyslice)
return 0;
t = tybase(t->sub[0]);
if (t->type != Tyslice)
return 0;
t = tybase(t->sub[0]);
if (t->type != Tybyte)
return 0;
}
return 1;
}
static void
verifyop(Node *n)
{
Type *ty;
ty = exprtype(n);
switch (exprop(n)) {
case Ostruct:
if (tybase(ty)->type != Tystruct)
fatal(n, "wrong type for struct literal: %s\n", tystr(ty));
break;
case Oarr:
if (tybase(ty)->type != Tyarray)
fatal(n, "wrong type for struct literal: %s\n", tystr(ty));
break;
default:
break;
}
}
/* After type inference, replace all type
* with the final computed type */
static void
typesub(Node *n, int noerr)
{
size_t i;
if (!n)
return;
switch (n->type) {
case Nfile:
pushstab(n->file.globls);
stabsub(n->file.globls);
for (i = 0; i < n->file.nstmts; i++)
typesub(n->file.stmts[i], noerr);
popstab();
break;
case Ndecl:
pushenv(n->decl.env);
settype(n, tyfix(n, type(n), noerr));
if (n->decl.init)
typesub(n->decl.init, noerr);
if (streq(declname(n), "main"))
if (!maincompatible(tybase(decltype(n))))
fatal(n, "main must be (->void) or (byte[:][:] -> void), got %s",
tystr(decltype(n)));
if (streq(declname(n), "__init__"))
if (!initcompatible(tybase(decltype(n))))
fatal(n, "__init__ must be (->void), got %s", tystr(decltype(n)));
popenv(n->decl.env);
break;
case Nblock:
pushstab(n->block.scope);
for (i = 0; i < n->block.nstmts; i++)
typesub(n->block.stmts[i], noerr);
popstab();
break;
case Nifstmt:
typesub(n->ifstmt.cond, noerr);
typesub(n->ifstmt.iftrue, noerr);
typesub(n->ifstmt.iffalse, noerr);
break;
case Nloopstmt:
typesub(n->loopstmt.cond, noerr);
typesub(n->loopstmt.init, noerr);
typesub(n->loopstmt.step, noerr);
typesub(n->loopstmt.body, noerr);
break;
case Niterstmt:
typesub(n->iterstmt.elt, noerr);
typesub(n->iterstmt.seq, noerr);
typesub(n->iterstmt.body, noerr);
additerspecializations(n, curstab());
break;
case Nmatchstmt:
typesub(n->matchstmt.val, noerr);
for (i = 0; i < n->matchstmt.nmatches; i++) {
typesub(n->matchstmt.matches[i], noerr);
}
break;
case Nmatch:
typesub(n->match.pat, noerr);
typesub(n->match.block, noerr);
break;
case Nexpr:
settype(n, tyfix(n, type(n), 0));
if (n->expr.param)
n->expr.param = tyfix(n, n->expr.param, 0);
typesub(n->expr.idx, noerr);
if (exprop(n) == Ocast && exprop(n->expr.args[0]) == Olit &&
n->expr.args[0]->expr.args[0]->lit.littype == Lint) {
settype(n->expr.args[0], exprtype(n));
settype(n->expr.args[0]->expr.args[0], exprtype(n));
}
for (i = 0; i < n->expr.nargs; i++)
typesub(n->expr.args[i], noerr);
if (!noerr)
verifyop(n);
break;
case Nfunc:
pushstab(n->func.scope);
settype(n, tyfix(n, n->func.type, 0));
for (i = 0; i < n->func.nargs; i++)
typesub(n->func.args[i], noerr);
typesub(n->func.body, noerr);
popstab();
break;
case Nlit:
settype(n, tyfix(n, type(n), 0));
switch (n->lit.littype) {
case Lfunc: typesub(n->lit.fnval, noerr); break;
case Lint: checkrange(n);
default: break;
}
break;
case Nimpl: putimpl(curstab(), n);
case Nname:
case Nuse: break;
case Nnone: die("Nnone should not be seen as node type!"); break;
}
}
static Type *
itertype(Node *n, Type *ret)
{
Type *it, *val, *itp, *valp, *fn;
it = exprtype(n);
itp = mktyptr(n->loc, it);
val = basetype(it);
if (!val)
die("FAIL! %s", tystr(it));
valp = mktyptr(n->loc, val);
fn = mktyfunc(n->loc, NULL, 0, ret);
lappend(&fn->sub, &fn->nsub, itp);
lappend(&fn->sub, &fn->nsub, valp);
return fn;
}
/* Take generics and build new versions of them
* with the type parameters replaced with the
* specialized types */
static void
specialize(Node *f)
{
Node *d, *n, *name;
Type *ty, *it;
size_t i;
Trait *tr;
for (i = 0; i < nimpldecl; i++) {
d = impldecl[i];
lappend(&file->file.stmts, &file->file.nstmts, d);
typesub(d, 0);
}
for (i = 0; i < nspecializations; i++) {
pushstab(specializationscope[i]);
n = specializations[i];
if (n->type == Nexpr) {
d = specializedcl(genericdecls[i], n->expr.param, n->expr.type, &name);
n->expr.args[0] = name;
n->expr.did = d->decl.did;
/* we need to sub in default types in the specialization, so call
* typesub on the specialized function */
typesub(d, 0);
} else if (n->type == Niterstmt) {
tr = traittab[Tciter];
assert(tr->nproto == 2);
ty = exprtype(n->iterstmt.seq);
it = itertype(n->iterstmt.seq, mktype(n->loc, Tybool));
d = specializedcl(tr->proto[0], ty, it, &name);
htput(tr->proto[0]->decl.impls, ty, d);
it = itertype(n->iterstmt.seq, mktype(n->loc, Tyvoid));
d = specializedcl(tr->proto[1], ty, it, &name);
htput(tr->proto[1]->decl.impls, ty, d);
} else {
die("unknown node for specialization\n");
}
popstab();
}
}
static void
applytraits(Node *f)
{
size_t i;
Node *impl, *n;
Trait *tr;
Type *ty;
Stab *ns;
tr = NULL;
pushstab(f->file.globls);
/* for now, traits can only be declared globally */
for (i = 0; i < nimpltab; i++) {
impl = impltab[i];
tr = impl->impl.trait;
if (!tr) {
n = impl->impl.traitname;
ns = file->file.globls;
if (n->name.ns)
ns = getns(file, n->name.ns);
if (ns)
tr = gettrait(ns, n);
if (!tr)
fatal(impl, "trait %s does not exist near %s",
namestr(impl->impl.traitname), ctxstr(impl));
if (tr->naux != impl->impl.naux)
fatal(impl, "incompatible implementation of %s: mismatched aux types",
namestr(impl->impl.traitname), ctxstr(impl));
}
pushenv(impl->impl.env);
ty = tf(impl->impl.type);
settrait(ty, tr);
if (tr->uid == Tciter) {
htput(seqbase, tf(impl->impl.type), tf(impl->impl.aux[0]));
}
popenv(impl->impl.env);
}
popstab();
}
void
verify(Node *f)
{
Node *n;
size_t i;
pushstab(f->file.globls);
/* for now, traits can only be declared globally */
for (i = 0; i < f->file.nstmts; i++) {
if (f->file.stmts[i]->type == Nimpl) {
n = f->file.stmts[i];
/* we merge, so we need to get it back again when error checking */
if (n->impl.isproto)
fatal(n, "missing implementation for prototype '%s %s'",
namestr(n->impl.traitname), tystr(n->impl.type));
}
}
}
void
infer(Node *file)
{
assert(file->type == Nfile);
delayed = mkht(tyhash, tyeq);
seqbase = mkht(tyhash, tyeq);
/* set up the symtabs */
loaduses(file);
// mergeexports(&st, file);
/* do the inference */
applytraits(file);
infernode(&file, NULL, NULL);
postinfer();
/* and replace type vars with actual types */
typesub(file, 0);
specialize(file);
verify(file);
}