blob: 80b0944d8baf9151fcb205c0c3737ca62763593c [file] [log] [blame]
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "go.h"
static Node* walkprint(Node*, NodeList**);
static Node* conv(Node*, Type*);
static Node* mapfn(char*, Type*);
static Node* makenewvar(Type*, NodeList**, Node**);
enum
{
Inone,
I2T,
I2T2,
I2I,
I2Ix,
I2I2,
T2I,
I2Isame,
E2T,
E2T2,
E2I,
E2I2,
I2E,
I2E2,
T2E,
E2Esame,
};
// can this code branch reach the end
// without an undcontitional RETURN
// this is hard, so it is conservative
int
walkret(NodeList *l)
{
Node *n;
loop:
while(l && l->next)
l = l->next;
if(l == nil)
return 1;
// at this point, we have the last
// statement of the function
n = l->n;
switch(n->op) {
case OBLOCK:
l = n->list;
goto loop;
case OGOTO:
case ORETURN:
case OPANIC:
case OPANICN:
return 0;
break;
}
// all other statements
// will flow to the end
return 1;
}
void
walk(Node *fn)
{
char s[50];
NodeList *l;
Node *n;
int lno;
curfn = fn;
if(debug['W']) {
snprint(s, sizeof(s), "\nbefore %S", curfn->nname->sym);
dumplist(s, curfn->nbody);
}
if(curfn->type->outtuple)
if(walkret(curfn->nbody))
yyerror("function ends without a return statement");
typechecklist(curfn->nbody, Etop);
lno = lineno;
for(l=fn->dcl; l; l=l->next) {
n = l->n;
if(n->op != ONAME || n->class != PAUTO)
continue;
lineno = n->lineno;
typecheck(&n, Erv | Easgn); // only needed for unused variables
if(!n->used && n->sym->name[0] != '&' && !nsyntaxerrors)
yyerror("%S declared and not used", n->sym);
}
lineno = lno;
if(nerrors != 0)
return;
walkstmtlist(curfn->nbody);
if(debug['W']) {
snprint(s, sizeof(s), "after walk %S", curfn->nname->sym);
dumplist(s, curfn->nbody);
}
heapmoves();
if(debug['W'] && curfn->enter != nil) {
snprint(s, sizeof(s), "enter %S", curfn->nname->sym);
dumplist(s, curfn->enter);
}
}
void
gettype(Node **np, NodeList **init)
{
if(debug['W'])
dump("\nbefore gettype", *np);
typecheck(np, Erv);
if(debug['W'])
dump("after gettype", *np);
}
void
walkdeflist(NodeList *l)
{
for(; l; l=l->next)
walkdef(l->n);
}
void
walkdef(Node *n)
{
int lno, maplineno, embedlineno;
NodeList *init;
Node *e;
Type *t;
lno = lineno;
setlineno(n);
if(n->op == ONONAME) {
if(!n->diag) {
n->diag = 1;
yyerror("undefined: %S", n->sym);
}
return;
}
if(n->walkdef == 1)
return;
if(n->walkdef == 2) {
// TODO(rsc): better loop message
fatal("loop");
}
n->walkdef = 2;
if(n->type != T || n->sym == S) // builtin or no name
goto ret;
init = nil;
switch(n->op) {
default:
fatal("walkdef %O", n->op);
case OLITERAL:
if(n->ntype != N) {
typecheck(&n->ntype, Etype);
n->type = n->ntype->type;
n->ntype = N;
if(n->type == T) {
n->diag = 1;
goto ret;
}
}
e = n->defn;
n->defn = N;
if(e == N) {
lineno = n->lineno;
dump("walkdef nil defn", n);
yyerror("xxx");
}
typecheck(&e, Erv | Eiota);
if(e->type != T && e->op != OLITERAL) {
yyerror("const initializer must be constant");
goto ret;
}
t = n->type;
if(t != T)
convlit(&e, t);
n->val = e->val;
n->type = e->type;
break;
case ONAME:
if(n->ntype != N) {
typecheck(&n->ntype, Etype);
n->type = n->ntype->type;
if(n->type == T) {
n->diag = 1;
goto ret;
}
}
if(n->type != T)
break;
if(n->defn == N)
fatal("var without type, init: %S", n->sym);
if(n->defn->op == ONAME) {
typecheck(&n->defn, Erv);
n->type = n->defn->type;
break;
}
typecheck(&n->defn, Etop); // fills in n->type
break;
case OTYPE:
n->walkdef = 1;
n->type = typ(TFORW);
n->type->sym = n->sym;
n->typecheck = 1;
typecheck(&n->ntype, Etype);
if((t = n->ntype->type) == T) {
n->diag = 1;
goto ret;
}
// copy new type and clear fields
// that don't come along
maplineno = n->type->maplineno;
embedlineno = n->type->embedlineno;
*n->type = *t;
t = n->type;
t->sym = n->sym;
t->local = n->local;
t->vargen = n->vargen;
t->siggen = 0;
t->printed = 0;
t->method = nil;
t->nod = N;
t->printed = 0;
t->deferwidth = 0;
// double-check use of type as map key
// TODO(rsc): also use of type as receiver?
if(maplineno) {
lineno = maplineno;
maptype(n->type, types[TBOOL]);
}
if(embedlineno) {
lineno = embedlineno;
if(isptr[t->etype])
yyerror("embedded type cannot be a pointer");
}
break;
case OPACK:
// nothing to see here
break;
}
ret:
lineno = lno;
n->walkdef = 1;
}
void
walkstmtlist(NodeList *l)
{
for(; l; l=l->next)
walkstmt(&l->n);
}
static int
samelist(NodeList *a, NodeList *b)
{
for(; a && b; a=a->next, b=b->next)
if(a->n != b->n)
return 0;
return a == b;
}
void
walkstmt(Node **np)
{
NodeList *init;
NodeList *ll, *rl;
int cl, lno;
Node *n;
n = *np;
if(n == N)
return;
lno = lineno;
setlineno(n);
switch(n->op) {
default:
if(n->op == ONAME)
yyerror("%S is not a top level statement", n->sym);
else
yyerror("%O is not a top level statement", n->op);
dump("nottop", n);
break;
case OAPPENDSTR:
case OASOP:
case OAS:
case OAS2:
case OAS2DOTTYPE:
case OAS2RECV:
case OAS2FUNC:
case OAS2MAPW:
case OAS2MAPR:
case OCLOSE:
case OCLOSED:
case OCOPY:
case OCALLMETH:
case OCALLINTER:
case OCALL:
case OCALLFUNC:
case OSEND:
case ORECV:
case OPRINT:
case OPRINTN:
case OPANIC:
case OPANICN:
case OEMPTY:
if(n->typecheck == 0)
fatal("missing typecheck");
init = n->ninit;
n->ninit = nil;
walkexpr(&n, &init);
n->ninit = concat(init, n->ninit);
break;
case OBREAK:
case ODCL:
case OCONTINUE:
case OFALL:
case OGOTO:
case OLABEL:
case ODCLCONST:
case ODCLTYPE:
break;
case OBLOCK:
walkstmtlist(n->list);
break;
case OXCASE:
yyerror("case statement out of place");
n->op = OCASE;
case OCASE:
walkstmt(&n->right);
break;
case ODEFER:
hasdefer = 1;
walkexpr(&n->left, &n->ninit);
break;
case OFOR:
walkstmtlist(n->ninit);
if(n->ntest != N) {
walkstmtlist(n->ntest->ninit);
walkexpr(&n->ntest, &n->ninit);
}
walkstmt(&n->nincr);
walkstmtlist(n->nbody);
break;
case OIF:
walkstmtlist(n->ninit);
walkexpr(&n->ntest, &n->ninit);
walkstmtlist(n->nbody);
walkstmtlist(n->nelse);
break;
case OPROC:
walkexpr(&n->left, &n->ninit);
break;
case ORETURN:
walkexprlist(n->list, &n->ninit);
if(curfn->type->outnamed && count(n->list) != 1) {
if(n->list == nil) {
// print("special return\n");
break;
}
// assign to the function out parameters,
// so that reorder3 can fix up conflicts
rl = nil;
for(ll=curfn->dcl; ll != nil; ll=ll->next) {
cl = ll->n->class & ~PHEAP;
if(cl == PAUTO)
break;
if(cl == PPARAMOUT)
rl = list(rl, ll->n);
}
if(samelist(rl, n->list)) {
// special return in disguise
n->list = nil;
break;
}
ll = ascompatee(n->op, rl, n->list, &n->ninit);
n->list = reorder3(ll);
break;
}
ll = ascompatte(n->op, getoutarg(curfn->type), n->list, 1, &n->ninit);
n->list = reorder4(ll);
break;
case OSELECT:
walkselect(n);
break;
case OSWITCH:
walkswitch(n);
break;
case ORANGE:
walkrange(n);
break;
case OXFALL:
yyerror("fallthrough statement out of place");
n->op = OFALL;
break;
}
*np = n;
}
/*
* walk the whole tree of the body of an
* expression or simple statement.
* the types expressions are calculated.
* compile-time constants are evaluated.
* complex side effects like statements are appended to init
*/
void
walkexprlist(NodeList *l, NodeList **init)
{
for(; l; l=l->next)
walkexpr(&l->n, init);
}
void
walkexpr(Node **np, NodeList **init)
{
Node *r, *l;
NodeList *ll, *lr;
Type *t;
int et;
int32 lno;
Node *n, *fn;
n = *np;
if(n == N)
return;
if(init == &n->ninit) {
// not okay to use n->ninit when walking n,
// because we might replace n with some other node
// and would lose the init list.
fatal("walkexpr init == &n->ninit");
}
// annoying case - not typechecked
if(n->op == OKEY) {
walkexpr(&n->left, init);
walkexpr(&n->right, init);
return;
}
lno = setlineno(n);
if(debug['w'] > 1)
dump("walk-before", n);
if(n->typecheck != 1) {
dump("missed typecheck", n);
fatal("missed typecheck");
}
t = T;
et = Txxx;
switch(n->op) {
default:
dump("walk", n);
fatal("walkexpr: switch 1 unknown op %N", n);
goto ret;
case OTYPE:
case ONONAME:
case OINDREG:
case OEMPTY:
goto ret;
case ONOT:
case OMINUS:
case OPLUS:
case OCOM:
case OLEN:
case OCAP:
case ODOT:
case ODOTPTR:
case ODOTMETH:
case ODOTINTER:
case OIND:
walkexpr(&n->left, init);
goto ret;
case OLSH:
case ORSH:
case OAND:
case OOR:
case OXOR:
case OANDAND:
case OOROR:
case OSUB:
case OMUL:
case OEQ:
case ONE:
case OLT:
case OLE:
case OGE:
case OGT:
case OADD:
walkexpr(&n->left, init);
walkexpr(&n->right, init);
goto ret;
case OPRINT:
case OPRINTN:
case OPANIC:
case OPANICN:
walkexprlist(n->list, init);
n = walkprint(n, init);
goto ret;
case OLITERAL:
n->addable = 1;
goto ret;
case ONAME:
if(!(n->class & PHEAP) && n->class != PPARAMREF)
n->addable = 1;
goto ret;
case OCALLINTER:
t = n->left->type;
if(n->list && n->list->n->op == OAS)
goto ret;
walkexpr(&n->left, init);
walkexprlist(n->list, init);
ll = ascompatte(n->op, getinarg(t), n->list, 0, init);
n->list = reorder1(ll);
goto ret;
case OCALLFUNC:
t = n->left->type;
if(n->list && n->list->n->op == OAS)
goto ret;
walkexpr(&n->left, init);
walkexprlist(n->list, init);
ll = ascompatte(n->op, getinarg(t), n->list, 0, init);
n->list = reorder1(ll);
if(isselect(n)) {
// special prob with selectsend and selectrecv:
// if chan is nil, they don't know big the channel
// element is and therefore don't know how to find
// the output bool, so we clear it before the call.
Node *b;
b = nodbool(0);
lr = ascompatte(n->op, getoutarg(t), list1(b), 0, init);
n->list = concat(n->list, lr);
}
goto ret;
case OCALLMETH:
t = n->left->type;
if(n->list && n->list->n->op == OAS)
goto ret;
walkexpr(&n->left, init);
walkexprlist(n->list, init);
ll = ascompatte(n->op, getinarg(t), n->list, 0, init);
lr = ascompatte(n->op, getthis(t), list1(n->left->left), 0, init);
ll = concat(ll, lr);
n->left->left = N;
ullmancalc(n->left);
n->list = reorder1(ll);
goto ret;
case OAS:
*init = concat(*init, n->ninit);
n->ninit = nil;
walkexpr(&n->left, init);
if(oaslit(n, init))
goto ret;
walkexpr(&n->right, init);
l = n->left;
r = n->right;
if(l == N || r == N)
goto ret;
r = ascompatee1(n->op, l, r, init);
if(r != N)
n = r;
goto ret;
case OAS2:
as2:
*init = concat(*init, n->ninit);
n->ninit = nil;
walkexprlist(n->list, init);
walkexprlist(n->rlist, init);
ll = ascompatee(OAS, n->list, n->rlist, init);
ll = reorder3(ll);
n = liststmt(ll);
goto ret;
case OAS2FUNC:
as2func:
// a,b,... = fn()
*init = concat(*init, n->ninit);
n->ninit = nil;
r = n->rlist->n;
walkexprlist(n->list, init);
walkexpr(&r, init);
ll = ascompatet(n->op, n->list, &r->type, 0, init);
n = liststmt(concat(list1(r), ll));
goto ret;
case OAS2RECV:
// a,b = <-c
*init = concat(*init, n->ninit);
n->ninit = nil;
r = n->rlist->n;
walkexprlist(n->list, init);
walkexpr(&r->left, init);
fn = chanfn("chanrecv2", 2, r->left->type);
r = mkcall1(fn, getoutargx(fn->type), init, r->left);
n->rlist->n = r;
n->op = OAS2FUNC;
goto as2func;
case OAS2MAPR:
// a,b = m[i];
*init = concat(*init, n->ninit);
n->ninit = nil;
r = n->rlist->n;
walkexprlist(n->list, init);
walkexpr(&r->left, init);
fn = mapfn("mapaccess2", r->left->type);
r = mkcall1(fn, getoutargx(fn->type), init, r->left, r->right);
n->rlist = list1(r);
n->op = OAS2FUNC;
goto as2func;
case OAS2MAPW:
// map[] = a,b - mapassign2
// a,b = m[i];
*init = concat(*init, n->ninit);
n->ninit = nil;
walkexprlist(n->list, init);
l = n->list->n;
t = l->left->type;
n = mkcall1(mapfn("mapassign2", t), T, init, l->left, l->right, n->rlist->n, n->rlist->next->n);
goto ret;
case OAS2DOTTYPE:
// a,b = i.(T)
*init = concat(*init, n->ninit);
n->ninit = nil;
r = n->rlist->n;
walkexprlist(n->list, init);
walkdottype(r, init);
et = ifaceas1(r->type, r->left->type, 1);
switch(et) {
case I2Isame:
case E2Esame:
n->rlist = list(list1(r->left), nodbool(1));
typechecklist(n->rlist, Erv);
goto as2;
case I2E:
n->list = list(list1(n->right), nodbool(1));
typechecklist(n->rlist, Erv);
goto as2;
case I2T:
et = I2T2;
break;
case I2Ix:
et = I2I2;
break;
case E2I:
et = E2I2;
break;
case E2T:
et = E2T2;
break;
default:
et = Inone;
break;
}
if(et == Inone)
break;
r = ifacecvt(r->type, r->left, et, init);
ll = ascompatet(n->op, n->list, &r->type, 0, init);
n = liststmt(concat(list1(r), ll));
goto ret;
case ODOTTYPE:
walkdottype(n, init);
walkconv(&n, init);
goto ret;
case OCONV:
case OCONVNOP:
if(thechar == '5') {
if(isfloat[n->left->type->etype] && (n->type->etype == TINT64 || n->type->etype == TUINT64)) {
n = mkcall("float64toint64", n->type, init, conv(n->left, types[TFLOAT64]));
goto ret;
}
if((n->left->type->etype == TINT64 || n->left->type->etype == TUINT64) && isfloat[n->type->etype]) {
n = mkcall("int64tofloat64", n->type, init, conv(n->left, types[TINT64]));
goto ret;
}
}
walkexpr(&n->left, init);
goto ret;
case OASOP:
walkexpr(&n->left, init);
l = n->left;
if(l->op == OINDEXMAP)
n = mapop(n, init);
walkexpr(&n->right, init);
if(n->etype == OANDNOT) {
n->etype = OAND;
n->right = nod(OCOM, n->right, N);
typecheck(&n->right, Erv);
goto ret;
}
/*
* on 32-bit arch, rewrite 64-bit ops into l = l op r
*/
et = n->left->type->etype;
if(widthptr == 4 && (et == TUINT64 || et == TINT64)) {
l = saferef(n->left, init);
r = nod(OAS, l, nod(n->etype, l, n->right));
typecheck(&r, Etop);
walkexpr(&r, init);
n = r;
}
goto ret;
case OANDNOT:
walkexpr(&n->left, init);
walkexpr(&n->right, init);
n->op = OAND;
n->right = nod(OCOM, n->right, N);
typecheck(&n->right, Erv);
goto ret;
case ODIV:
case OMOD:
/*
* rewrite div and mod into function calls
* on 32-bit architectures.
*/
walkexpr(&n->left, init);
walkexpr(&n->right, init);
et = n->left->type->etype;
if(widthptr > 4 || (et != TUINT64 && et != TINT64))
goto ret;
if(et == TINT64)
strcpy(namebuf, "int64");
else
strcpy(namebuf, "uint64");
if(n->op == ODIV)
strcat(namebuf, "div");
else
strcat(namebuf, "mod");
n = mkcall(namebuf, n->type, init,
conv(n->left, types[et]), conv(n->right, types[et]));
goto ret;
case OINDEX:
walkexpr(&n->left, init);
walkexpr(&n->right, init);
// if range of type cannot exceed static array bound,
// disable bounds check
if(!isslice(n->left->type))
if(n->right->type->width < 4)
if((1<<(8*n->right->type->width)) <= n->left->type->bound)
n->etype = 1;
goto ret;
case OINDEXMAP:
if(n->etype == 1)
goto ret;
t = n->left->type;
n = mkcall1(mapfn("mapaccess1", t), t->type, init, n->left, n->right);
goto ret;
case ORECV:
walkexpr(&n->left, init);
walkexpr(&n->right, init);
n = mkcall1(chanfn("chanrecv1", 2, n->left->type), n->type, init, n->left);
goto ret;
case OSLICE:
walkexpr(&n->left, init);
walkexpr(&n->right->left, init);
walkexpr(&n->right->right, init);
// dynamic slice
// sliceslice(old []any, lb int, hb int, width int) (ary []any)
// sliceslice1(old []any, lb int, width int) (ary []any)
t = n->type;
if(n->right->right != N) {
fn = syslook("sliceslice", 1);
argtype(fn, t->type); // any-1
argtype(fn, t->type); // any-2
n = mkcall1(fn, t, init,
n->left,
conv(n->right->left, types[TINT]),
conv(n->right->right, types[TINT]),
nodintconst(t->type->width));
} else {
fn = syslook("sliceslice1", 1);
argtype(fn, t->type); // any-1
argtype(fn, t->type); // any-2
n = mkcall1(fn, t, init,
n->left,
conv(n->right->left, types[TINT]),
nodintconst(t->type->width));
}
goto ret;
case OSLICEARR:
walkexpr(&n->left, init);
walkexpr(&n->right->left, init);
walkexpr(&n->right->right, init);
// static slice
// slicearray(old *any, nel int, lb int, hb int, width int) (ary []any)
t = n->type;
fn = syslook("slicearray", 1);
argtype(fn, n->left->type); // any-1
argtype(fn, t->type); // any-2
if(n->right->right == N)
r = nodintconst(n->left->type->bound);
else
r = conv(n->right->right, types[TINT]);
n = mkcall1(fn, t, init,
nod(OADDR, n->left, N), nodintconst(n->left->type->bound),
conv(n->right->left, types[TINT]),
r,
nodintconst(t->type->width));
goto ret;
case OCONVSLICE:
// slicearray(old *any, nel int, lb int, hb int, width int) (ary []any)
fn = syslook("slicearray", 1);
argtype(fn, n->left->type->type); // any-1
argtype(fn, n->type->type); // any-2
n = mkcall1(fn, n->type, init, n->left,
nodintconst(n->left->type->type->bound),
nodintconst(0),
nodintconst(n->left->type->type->bound),
nodintconst(n->type->type->width));
goto ret;
case OADDR:;
Node *nvar, *nstar;
// turn &Point(1, 2) or &[]int(1, 2) or &[...]int(1, 2) into allocation.
// initialize with
// nvar := new(*Point);
// *nvar = Point(1, 2);
// and replace expression with nvar
switch(n->left->op) {
case OARRAYLIT:
case OMAPLIT:
case OSTRUCTLIT:
nvar = makenewvar(n->type, init, &nstar);
anylit(n->left, nstar, init);
n = nvar;
goto ret;
}
walkexpr(&n->left, init);
goto ret;
case ONEW:
n = callnew(n->type->type);
goto ret;
case OCMPSTR:
// sys_cmpstring(s1, s2) :: 0
r = mkcall("cmpstring", types[TINT], init,
conv(n->left, types[TSTRING]),
conv(n->right, types[TSTRING]));
r = nod(n->etype, r, nodintconst(0));
typecheck(&r, Erv);
n = r;
goto ret;
case OADDSTR:
// sys_catstring(s1, s2)
n = mkcall("catstring", n->type, init,
conv(n->left, types[TSTRING]),
conv(n->right, types[TSTRING]));
goto ret;
case OAPPENDSTR:
// s1 = sys_catstring(s1, s2)
if(n->etype != OADD)
fatal("walkasopstring: not add");
r = mkcall("catstring", n->left->type, init,
conv(n->left, types[TSTRING]),
conv(n->right, types[TSTRING]));
r = nod(OAS, n->left, r);
n = r;
goto ret;
case OSLICESTR:
// sys_slicestring(s, lb, hb)
if(n->right->right) {
n = mkcall("slicestring", n->type, init,
conv(n->left, types[TSTRING]),
conv(n->right->left, types[TINT]),
conv(n->right->right, types[TINT]));
} else {
n = mkcall("slicestring1", n->type, init,
conv(n->left, types[TSTRING]),
conv(n->right->left, types[TINT]));
}
goto ret;
case OINDEXSTR:
// TODO(rsc): should be done in back end
// sys_indexstring(s, i)
n = mkcall("indexstring", n->type, init,
conv(n->left, types[TSTRING]),
conv(n->right, types[TINT]));
goto ret;
case OCOPY:
fn = syslook("slicecopy", 1);
argtype(fn, n->left->type);
argtype(fn, n->right->type);
n = mkcall1(fn, n->type, init,
n->left, n->right,
nodintconst(n->left->type->type->width));
goto ret;
case OCLOSE:
// cannot use chanfn - closechan takes any, not chan any
fn = syslook("closechan", 1);
argtype(fn, n->left->type);
n = mkcall1(fn, T, init, n->left);
goto ret;
case OCLOSED:
// cannot use chanfn - closechan takes any, not chan any
fn = syslook("closedchan", 1);
argtype(fn, n->left->type);
n = mkcall1(fn, n->type, init, n->left);
goto ret;
case OMAKECHAN:
n = mkcall1(chanfn("makechan", 1, n->type), n->type, init,
typename(n->type->type),
conv(n->left, types[TINT]));
goto ret;
case OMAKEMAP:
t = n->type;
fn = syslook("makemap", 1);
argtype(fn, t->down); // any-1
argtype(fn, t->type); // any-2
n = mkcall1(fn, n->type, init,
typename(t->down), // key type
typename(t->type), // value type
conv(n->left, types[TINT]));
goto ret;
case OMAKESLICE:
// makeslice(nel int, max int, width int) (ary []any)
t = n->type;
fn = syslook("makeslice", 1);
argtype(fn, t->type); // any-1
n = mkcall1(fn, n->type, nil,
typename(n->type),
conv(n->left, types[TINT]),
conv(n->right, types[TINT]));
goto ret;
case ORUNESTR:
// sys_intstring(v)
n = mkcall("intstring", n->type, init,
conv(n->left, types[TINT64])); // TODO(rsc): int64?!
goto ret;
case OARRAYBYTESTR:
// slicebytetostring([]byte) string;
n = mkcall("slicebytetostring", n->type, init, n->left);
goto ret;
case OARRAYRUNESTR:
// sliceinttostring([]byte) string;
n = mkcall("sliceinttostring", n->type, init, n->left);
goto ret;
case OCMPIFACE:
// ifaceeq(i1 any-1, i2 any-2) (ret bool);
if(!eqtype(n->left->type, n->right->type))
fatal("ifaceeq %O %T %T", n->op, n->left->type, n->right->type);
if(isnilinter(n->left->type))
fn = syslook("efaceeq", 1);
else
fn = syslook("ifaceeq", 1);
argtype(fn, n->right->type);
argtype(fn, n->left->type);
r = mkcall1(fn, n->type, init, n->left, n->right);
if(n->etype == ONE) {
r = nod(ONOT, r, N);
typecheck(&r, Erv);
}
n = r;
goto ret;
case OARRAYLIT:
case OMAPLIT:
case OSTRUCTLIT:
nvar = nod(OXXX, N, N);
tempname(nvar, n->type);
anylit(n, nvar, init);
n = nvar;
goto ret;
case OSEND:
n = mkcall1(chanfn("chansend1", 2, n->left->type), T, init, n->left, n->right);
goto ret;
case OSENDNB:
n = mkcall1(chanfn("chansend2", 2, n->left->type), n->type, init, n->left, n->right);
goto ret;
case OCONVIFACE:
walkexpr(&n->left, init);
n = ifacecvt(n->type, n->left, n->etype, init);
goto ret;
case OCLOSURE:
n = walkclosure(n, init);
goto ret;
}
fatal("missing switch %O", n->op);
ret:
if(debug['w'] && n != N)
dump("walk", n);
ullmancalc(n);
lineno = lno;
*np = n;
}
Node*
makenewvar(Type *t, NodeList **init, Node **nstar)
{
Node *nvar, *nas;
nvar = nod(OXXX, N, N);
tempname(nvar, t);
nas = nod(OAS, nvar, callnew(t->type));
typecheck(&nas, Etop);
walkexpr(&nas, init);
*init = list(*init, nas);
*nstar = nod(OIND, nvar, N);
typecheck(nstar, Erv);
return nvar;
}
// TODO(rsc): cut
void
walkdottype(Node *n, NodeList **init)
{
walkexpr(&n->left, init);
if(n->left == N)
return;
if(n->right != N) {
walkexpr(&n->right, init);
n->type = n->right->type;
n->right = N;
}
}
// TODO(rsc): cut
void
walkconv(Node **np, NodeList **init)
{
int et;
char *what;
Type *t;
Node *l;
Node *n;
n = *np;
t = n->type;
if(t == T)
return;
walkexpr(&n->left, init);
l = n->left;
if(l == N)
return;
if(l->type == T)
return;
// if using .(T), interface assertion.
if(n->op == ODOTTYPE) {
et = ifaceas1(t, l->type, 1);
if(et == I2Isame || et == E2Esame) {
n->op = OCONVNOP;
return;
}
if(et != Inone) {
n = ifacecvt(t, l, et, init);
*np = n;
return;
}
goto bad;
}
fatal("walkconv");
bad:
if(n->diag)
return;
n->diag = 1;
if(n->op == ODOTTYPE)
what = "type assertion";
else
what = "conversion";
if(l->type != T)
yyerror("invalid %s: %T to %T", what, l->type, t);
}
Node*
ascompatee1(int op, Node *l, Node *r, NodeList **init)
{
return convas(nod(OAS, l, r), init);
}
NodeList*
ascompatee(int op, NodeList *nl, NodeList *nr, NodeList **init)
{
NodeList *ll, *lr, *nn;
/*
* check assign expression list to
* a expression list. called in
* expr-list = expr-list
*/
nn = nil;
for(ll=nl, lr=nr; ll && lr; ll=ll->next, lr=lr->next)
nn = list(nn, ascompatee1(op, ll->n, lr->n, init));
// cannot happen: caller checked that lists had same length
if(ll || lr)
yyerror("error in shape across %O", op);
return nn;
}
/*
* l is an lv and rt is the type of an rv
* return 1 if this implies a function call
* evaluating the lv or a function call
* in the conversion of the types
*/
int
fncall(Node *l, Type *rt)
{
if(l->ullman >= UINF)
return 1;
if(eqtype(l->type, rt))
return 0;
return 1;
}
NodeList*
ascompatet(int op, NodeList *nl, Type **nr, int fp, NodeList **init)
{
Node *l, *tmp, *a;
NodeList *ll;
Type *r;
Iter saver;
int ucount;
NodeList *nn, *mm;
/*
* check assign type list to
* a expression list. called in
* expr-list = func()
*/
r = structfirst(&saver, nr);
nn = nil;
mm = nil;
ucount = 0;
for(ll=nl; ll; ll=ll->next) {
if(r == T)
break;
l = ll->n;
if(isblank(l)) {
r = structnext(&saver);
continue;
}
// any lv that causes a fn call must be
// deferred until all the return arguments
// have been pulled from the output arguments
if(fncall(l, r->type)) {
tmp = nod(OXXX, N, N);
tempname(tmp, r->type);
a = nod(OAS, l, tmp);
a = convas(a, init);
mm = list(mm, a);
l = tmp;
}
a = nod(OAS, l, nodarg(r, fp));
a = convas(a, init);
ullmancalc(a);
if(a->ullman >= UINF)
ucount++;
nn = list(nn, a);
r = structnext(&saver);
}
if(ll != nil || r != T)
yyerror("assignment count mismatch: %d = %d",
count(nl), structcount(*nr));
if(ucount)
yyerror("reorder2: too many function calls evaluating parameters");
return concat(nn, mm);
}
/*
* make a tsig for the structure
* carrying the ... arguments
*/
Type*
sigtype(Type *st)
{
Sym *s;
Type *t;
static int sigdddgen;
dowidth(st);
sigdddgen++;
snprint(namebuf, sizeof(namebuf), "dsigddd_%d", sigdddgen);
s = lookup(namebuf);
t = newtype(s);
t = dodcltype(t);
updatetype(t, st);
t->local = 1;
return t;
}
/*
* package all the arguments that
* match a ... parameter into an
* automatic structure.
* then call the ... arg (interface)
* with a pointer to the structure.
*/
NodeList*
mkdotargs(NodeList *lr0, NodeList *nn, Type *l, int fp, NodeList **init)
{
Node *r;
Type *t, *st, *ft;
Node *a, *var;
NodeList *lr, *n;
n = nil; // list of assignments
st = typ(TSTRUCT); // generated structure
ft = T; // last field
for(lr=lr0; lr; lr=lr->next) {
r = lr->n;
if(r->op == OLITERAL && r->val.ctype == CTNIL) {
if(r->type == T || r->type->etype == TNIL) {
yyerror("inappropriate use of nil in ... argument");
return nil;
}
}
defaultlit(&r, T);
lr->n = r;
if(r->type == T) // type check failed
return nil;
// generate the next structure field
t = typ(TFIELD);
t->type = r->type;
if(ft == T)
st->type = t;
else
ft->down = t;
ft = t;
a = nod(OAS, N, r);
n = list(n, a);
}
// make a named type for the struct
st = sigtype(st);
dowidth(st);
// now we have the size, make the struct
var = nod(OXXX, N, N);
tempname(var, st);
var->sym = lookup(".ddd");
// assign the fields to the struct.
// use the init list so that reorder1 doesn't reorder
// these assignments after the interface conversion
// below.
t = st->type;
for(lr=n; lr; lr=lr->next) {
r = lr->n;
r->left = nod(OXXX, N, N);
*r->left = *var;
r->left->type = r->right->type;
r->left->xoffset += t->width;
typecheck(&r, Etop);
walkexpr(&r, init);
lr->n = r;
t = t->down;
}
*init = concat(*init, n);
// last thing is to put assignment
// of the structure to the DDD parameter
a = nod(OAS, nodarg(l, fp), var);
nn = list(nn, convas(a, init));
return nn;
}
/*
* helpers for shape errors
*/
static void
dumptypes(Type **nl, char *what)
{
int first;
Type *l;
Iter savel;
l = structfirst(&savel, nl);
print("\t");
first = 1;
for(l = structfirst(&savel, nl); l != T; l = structnext(&savel)) {
if(first)
first = 0;
else
print(", ");
print("%T", l);
}
if(first)
print("[no arguments %s]", what);
print("\n");
}
static void
dumpnodetypes(NodeList *l, char *what)
{
int first;
Node *r;
print("\t");
first = 1;
for(; l; l=l->next) {
r = l->n;
if(first)
first = 0;
else
print(", ");
print("%T", r->type);
}
if(first)
print("[no arguments %s]", what);
print("\n");
}
/*
* check assign expression list to
* a type list. called in
* return expr-list
* func(expr-list)
*/
NodeList*
ascompatte(int op, Type **nl, NodeList *lr, int fp, NodeList **init)
{
Type *l, *ll;
Node *r, *a;
NodeList *nn, *lr0, *alist;
Iter savel, peekl;
lr0 = lr;
l = structfirst(&savel, nl);
r = N;
if(lr)
r = lr->n;
nn = nil;
// 1 to many
peekl = savel;
if(l != T && r != N && structnext(&peekl) != T && lr->next == nil
&& r->type->etype == TSTRUCT && r->type->funarg) {
// optimization - can do block copy
if(eqtypenoname(r->type, *nl)) {
a = nodarg(*nl, fp);
a->type = r->type;
nn = list1(convas(nod(OAS, a, r), init));
goto ret;
}
// conversions involved.
// copy into temporaries.
alist = nil;
for(l=structfirst(&savel, &r->type); l; l=structnext(&savel)) {
a = nod(OXXX, N, N);
tempname(a, l->type);
alist = list(alist, a);
}
a = nod(OAS2, N, N);
a->list = alist;
a->rlist = lr;
typecheck(&a, Etop);
walkstmt(&a);
*init = list(*init, a);
lr = alist;
r = lr->n;
l = structfirst(&savel, nl);
}
loop:
if(l != T && isddd(l->type)) {
// the ddd parameter must be last
ll = structnext(&savel);
if(ll != T)
yyerror("... must be last argument");
// special case --
// only if we are assigning a single ddd
// argument to a ddd parameter then it is
// passed thru unencapsulated
if(r != N && lr->next == nil && isddd(r->type)) {
a = nod(OAS, nodarg(l, fp), r);
a = convas(a, init);
nn = list(nn, a);
goto ret;
}
// normal case -- make a structure of all
// remaining arguments and pass a pointer to
// it to the ddd parameter (empty interface)
nn = mkdotargs(lr, nn, l, fp, init);
goto ret;
}
if(l == T || r == N) {
if(l != T || r != N) {
if(l != T)
yyerror("xxx not enough arguments to %O", op);
else
yyerror("xxx too many arguments to %O", op);
dumptypes(nl, "expected");
dumpnodetypes(lr0, "given");
}
goto ret;
}
a = nod(OAS, nodarg(l, fp), r);
a = convas(a, init);
nn = list(nn, a);
l = structnext(&savel);
r = N;
lr = lr->next;
if(lr != nil)
r = lr->n;
goto loop;
ret:
for(lr=nn; lr; lr=lr->next)
lr->n->typecheck = 1;
return nn;
}
// generate code for print
static Node*
walkprint(Node *nn, NodeList **init)
{
Node *r;
Node *n;
NodeList *l, *all;
Node *on;
Type *t;
int notfirst, et, op;
NodeList *calls;
op = nn->op;
all = nn->list;
calls = nil;
notfirst = 0;
for(l=all; l; l=l->next) {
if(notfirst)
calls = list(calls, mkcall("printsp", T, init));
notfirst = op == OPRINTN || op == OPANICN;
n = l->n;
if(n->op == OLITERAL) {
switch(n->val.ctype) {
case CTINT:
defaultlit(&n, types[TINT64]);
break;
case CTFLT:
defaultlit(&n, types[TFLOAT64]);
break;
}
}
if(n->op != OLITERAL && n->type && n->type->etype == TIDEAL)
defaultlit(&n, types[TINT64]);
defaultlit(&n, nil);
l->n = n;
if(n->type == T || n->type->etype == TFORW)
continue;
et = n->type->etype;
if(isinter(n->type)) {
if(isnilinter(n->type))
on = syslook("printeface", 1);
else
on = syslook("printiface", 1);
argtype(on, n->type); // any-1
} else if(isptr[et] || et == TCHAN || et == TMAP || et == TFUNC) {
on = syslook("printpointer", 1);
argtype(on, n->type); // any-1
} else if(isslice(n->type)) {
on = syslook("printslice", 1);
argtype(on, n->type); // any-1
} else if(isint[et]) {
if(et == TUINT64)
on = syslook("printuint", 0);
else
on = syslook("printint", 0);
} else if(isfloat[et]) {
on = syslook("printfloat", 0);
} else if(et == TBOOL) {
on = syslook("printbool", 0);
} else if(et == TSTRING) {
on = syslook("printstring", 0);
} else {
badtype(OPRINT, n->type, T);
continue;
}
t = *getinarg(on->type);
if(t != nil)
t = t->type;
if(t != nil)
t = t->type;
if(!eqtype(t, n->type)) {
n = nod(OCONV, n, N);
n->type = t;
}
r = nod(OCALL, on, N);
r->list = list1(n);
calls = list(calls, r);
}
if(op == OPRINTN)
calls = list(calls, mkcall("printnl", T, nil));
typechecklist(calls, Etop);
walkexprlist(calls, init);
if(op == OPANIC || op == OPANICN)
r = mkcall("panicl", T, nil);
else
r = nod(OEMPTY, N, N);
typecheck(&r, Etop);
walkexpr(&r, init);
r->ninit = calls;
return r;
}
Node*
callnew(Type *t)
{
Node *fn;
dowidth(t);
fn = syslook("mal", 1);
argtype(fn, t);
return mkcall1(fn, ptrto(t), nil, nodintconst(t->width));
}
Type*
fixchan(Type *t)
{
if(t == T)
goto bad;
if(t->etype != TCHAN)
goto bad;
if(t->type == T)
goto bad;
dowidth(t->type);
return t;
bad:
yyerror("not a channel: %lT", t);
return T;
}
Node*
mapop(Node *n, NodeList **init)
{
Node *r, *a;
r = n;
switch(n->op) {
default:
fatal("mapop: unknown op %O", n->op);
case OASOP:
// rewrite map[index] op= right
// into tmpi := index; map[tmpi] = map[tmpi] op right
// make it ok to double-evaluate map[tmpi]
n->left->left = safeval(n->left->left, init);
n->left->right = safeval(n->left->right, init);
a = nod(OXXX, N, N);
*a = *n->left; // copy of map[tmpi]
a->etype = 0;
a = nod(n->etype, a, n->right); // m[tmpi] op right
r = nod(OAS, n->left, a); // map[tmpi] = map[tmpi] op right
typecheck(&r, Etop);
walkexpr(&r, init);
break;
}
return r;
}
/*
* assigning src to dst involving interfaces?
* return op to use.
*/
int
ifaceas1(Type *dst, Type *src, int explicit)
{
if(src == T || dst == T)
return Inone;
if(explicit && !isinter(src))
yyerror("cannot use .(T) on non-interface type %T", src);
if(isinter(dst)) {
if(isinter(src)) {
if(isnilinter(dst)) {
if(isnilinter(src))
return E2Esame;
return I2E;
}
if(eqtype(dst, src))
return I2Isame;
ifacecheck(dst, src, lineno, explicit);
if(isnilinter(src))
return E2I;
if(explicit)
return I2Ix;
return I2I;
}
if(isnilinter(dst))
return T2E;
ifacecheck(dst, src, lineno, explicit);
return T2I;
}
if(isinter(src)) {
ifacecheck(dst, src, lineno, explicit);
if(isnilinter(src))
return E2T;
return I2T;
}
return Inone;
}
/*
* treat convert T to T as noop
*/
int
ifaceas(Type *dst, Type *src, int explicit)
{
int et;
et = ifaceas1(dst, src, explicit);
if(et == I2Isame || et == E2Esame)
et = Inone;
return et;
}
static char*
ifacename[] =
{
[I2T] = "ifaceI2T",
[I2T2] = "ifaceI2T2",
[I2I] = "ifaceI2I",
[I2Ix] = "ifaceI2Ix",
[I2I2] = "ifaceI2I2",
[I2Isame] = "ifaceI2Isame",
[E2T] = "ifaceE2T",
[E2T2] = "ifaceE2T2",
[E2I] = "ifaceE2I",
[E2I2] = "ifaceE2I2",
[I2E] = "ifaceI2E",
[I2E2] = "ifaceI2E2",
[T2I] = "ifaceT2I",
[T2E] = "ifaceT2E",
[E2Esame] = "ifaceE2Esame",
};
Node*
ifacecvt(Type *tl, Node *n, int et, NodeList **init)
{
Type *tr;
Node *r, *on;
NodeList *args;
tr = n->type;
switch(et) {
default:
fatal("ifacecvt: unknown op %d\n", et);
case I2Isame:
case E2Esame:
return n;
case T2I:
// ifaceT2I(sigi *byte, sigt *byte, elem any) (ret any);
args = list1(typename(tl)); // sigi
args = list(args, typename(tr)); // sigt
args = list(args, n); // elem
on = syslook("ifaceT2I", 1);
argtype(on, tr);
argtype(on, tl);
dowidth(on->type);
break;
case I2T:
case I2T2:
case I2I:
case I2Ix:
case I2I2:
case E2T:
case E2T2:
case E2I:
case E2I2:
// iface[IT]2[IT][2](sigt *byte, iface any) (ret any[, ok bool]);
args = list1(typename(tl)); // sigi or sigt
args = list(args, n); // iface
on = syslook(ifacename[et], 1);
argtype(on, tr);
argtype(on, tl);
break;
case I2E:
// TODO(rsc): Should do this in back end, without a call.
// ifaceI2E(elem any) (ret any);
args = list1(n); // elem
on = syslook("ifaceI2E", 1);
argtype(on, tr);
argtype(on, tl);
break;
case T2E:
// TODO(rsc): Should do this in back end for pointer case, without a call.
// ifaceT2E(sigt *byte, elem any) (ret any);
args = list1(typename(tr)); // sigt
args = list(args, n); // elem
on = syslook("ifaceT2E", 1);
argtype(on, tr);
argtype(on, tl);
break;
}
dowidth(on->type);
r = nod(OCALL, on, N);
r->list = args;
typecheck(&r, Erv | Efnstruct);
walkexpr(&r, init);
return r;
}
Node*
convas(Node *n, NodeList **init)
{
Node *l, *r;
Type *lt, *rt;
int et;
if(n->op != OAS)
fatal("convas: not OAS %O", n->op);
n->typecheck = 1;
lt = T;
rt = T;
l = n->left;
r = n->right;
if(l == N || r == N)
goto out;
lt = l->type;
rt = r->type;
if(lt == T || rt == T)
goto out;
if(isblank(n->left))
goto out;
if(n->left->op == OINDEXMAP) {
n = mkcall1(mapfn("mapassign1", n->left->left->type), T, init,
n->left->left, n->left->right, n->right);
goto out;
}
if(eqtype(lt, rt))
goto out;
et = ifaceas(lt, rt, 0);
if(et != Inone) {
n->right = ifacecvt(lt, r, et, init);
goto out;
}
out:
ullmancalc(n);
return n;
}
/*
* from ascompat[te]
* evaluating actual function arguments.
* f(a,b)
* if there is exactly one function expr,
* then it is done first. otherwise must
* make temp variables
*/
NodeList*
reorder1(NodeList *all)
{
Node *f, *a, *n;
NodeList *l, *r, *g;
int c, d, t;
c = 0; // function calls
t = 0; // total parameters
for(l=all; l; l=l->next) {
n = l->n;
t++;
ullmancalc(n);
if(n->ullman >= UINF)
c++;
}
if(c == 0 || t == 1)
return all;
g = nil; // fncalls assigned to tempnames
f = N; // last fncall assigned to stack
r = nil; // non fncalls and tempnames assigned to stack
d = 0;
for(l=all; l; l=l->next) {
n = l->n;
if(n->ullman < UINF) {
r = list(r, n);
continue;
}
d++;
if(d == c) {
f = n;
continue;
}
// make assignment of fncall to tempname
a = nod(OXXX, N, N);
tempname(a, n->right->type);
a = nod(OAS, a, n->right);
g = list(g, a);
// put normal arg assignment on list
// with fncall replaced by tempname
n->right = a->left;
r = list(r, n);
}
if(f != N)
g = list(g, f);
return concat(g, r);
}
/*
* from ascompat[ee]
* a,b = c,d
* simultaneous assignment. there cannot
* be later use of an earlier lvalue.
*/
int
vmatch2(Node *l, Node *r)
{
NodeList *ll;
/*
* isolate all right sides
*/
if(r == N)
return 0;
switch(r->op) {
case ONAME:
// match each right given left
if(l == r)
return 1;
case OLITERAL:
return 0;
}
if(vmatch2(l, r->left))
return 1;
if(vmatch2(l, r->right))
return 1;
for(ll=r->list; ll; ll=ll->next)
if(vmatch2(l, ll->n))
return 1;
return 0;
}
int
vmatch1(Node *l, Node *r)
{
NodeList *ll;
/*
* isolate all left sides
*/
if(l == N || r == N)
return 0;
switch(l->op) {
case ONAME:
switch(l->class) {
case PPARAM:
case PPARAMREF:
case PAUTO:
break;
default:
// assignment to non-stack variable
// must be delayed if right has function calls.
if(r->ullman >= UINF)
return 1;
break;
}
return vmatch2(l, r);
case OLITERAL:
return 0;
}
if(vmatch1(l->left, r))
return 1;
if(vmatch1(l->right, r))
return 1;
for(ll=l->list; ll; ll=ll->next)
if(vmatch1(ll->n, r))
return 1;
return 0;
}
NodeList*
reorder3(NodeList *all)
{
Node *n1, *n2, *q;
int c1, c2;
NodeList *l1, *l2, *r;
r = nil;
for(l1=all, c1=0; l1; l1=l1->next, c1++) {
n1 = l1->n;
for(l2=all, c2=0; l2; l2=l2->next, c2++) {
n2 = l2->n;
if(c2 > c1) {
if(vmatch1(n1->left, n2->right)) {
// delay assignment to n1->left
q = nod(OXXX, N, N);
tempname(q, n1->right->type);
q = nod(OAS, n1->left, q);
n1->left = q->right;
r = list(r, q);
break;
}
}
}
}
return concat(all, r);
}
NodeList*
reorder4(NodeList *ll)
{
/*
* from ascompat[te]
* return c,d
* return expression assigned to output
* parameters. there may be no problems.
*
* TODO(rsc): i don't believe that.
* func f() (a, b int) {
* a, b = 1, 2;
* return b, a;
* }
*/
return ll;
}
/*
* walk through argin parameters.
* generate and return code to allocate
* copies of escaped parameters to the heap.
*/
NodeList*
paramstoheap(Type **argin)
{
Type *t;
Iter savet;
Node *v;
NodeList *nn;
nn = nil;
for(t = structfirst(&savet, argin); t != T; t = structnext(&savet)) {
v = t->nname;
if(v == N || !(v->class & PHEAP))
continue;
// generate allocation & copying code
nn = list(nn, nod(OAS, v->heapaddr, v->alloc));
nn = list(nn, nod(OAS, v, v->stackparam));
}
return nn;
}
/*
* take care of migrating any function in/out args
* between the stack and the heap. adds code to
* curfn's before and after lists.
*/
void
heapmoves(void)
{
NodeList *nn;
nn = paramstoheap(getthis(curfn->type));
nn = concat(nn, paramstoheap(getinarg(curfn->type)));
curfn->enter = concat(curfn->enter, nn);
}
static Node*
vmkcall(Node *fn, Type *t, NodeList **init, va_list va)
{
int i, n;
Node *r;
NodeList *args;
if(fn->type == T || fn->type->etype != TFUNC)
fatal("mkcall %#N %T", fn, fn->type);
args = nil;
n = fn->type->intuple;
for(i=0; i<n; i++)
args = list(args, va_arg(va, Node*));
r = nod(OCALL, fn, N);
r->list = args;
if(fn->type->outtuple > 0)
typecheck(&r, Erv | Efnstruct);
else
typecheck(&r, Etop);
walkexpr(&r, init);
r->type = t;
return r;
}
Node*
mkcall(char *name, Type *t, NodeList **init, ...)
{
Node *r;
va_list va;
va_start(va, init);
r = vmkcall(syslook(name, 0), t, init, va);
va_end(va);
return r;
}
Node*
mkcall1(Node *fn, Type *t, NodeList **init, ...)
{
Node *r;
va_list va;
va_start(va, init);
r = vmkcall(fn, t, init, va);
va_end(va);
return r;
}
static Node*
conv(Node *n, Type *t)
{
if(eqtype(n->type, t))
return n;
n = nod(OCONV, n, N);
n->type = t;
typecheck(&n, Erv);
return n;
}
Node*
chanfn(char *name, int n, Type *t)
{
Node *fn;
int i;
if(t->etype != TCHAN)
fatal("chanfn %T", t);
fn = syslook(name, 1);
for(i=0; i<n; i++)
argtype(fn, t->type);
return fn;
}
static Node*
mapfn(char *name, Type *t)
{
Node *fn;
if(t->etype != TMAP)
fatal("mapfn %T", t);
fn = syslook(name, 1);
argtype(fn, t->down);
argtype(fn, t->type);
argtype(fn, t->down);
argtype(fn, t->type);
return fn;
}