closures - 6g support

R=ken
OCL=24501
CL=24566

src/cmd/6g/cgen.c

@@ -205,7 +205,7 @@ cgen(Node *n, Node *res)
 	case ODOTPTR:
 	case OINDEX:
 	case OIND:
-	case ONAME:	// PHEAP var
+	case ONAME:	// PHEAP or PPARAMREF var
 		igen(n, &n1, res);
 		gmove(&n1, res);
 		regfree(&n1);
@@ -526,9 +526,18 @@ agen(Node *n, Node *res)
 		break;
 
 	case ONAME:
-		// should only get here for heap vars
-		if(!(n->class & PHEAP))
+		// should only get here with names in this func.
+		if(n->funcdepth > 0 && n->funcdepth != funcdepth) {
+			dump("bad agen", n);
+			fatal("agen: bad ONAME funcdepth %d != %d",
+				n->funcdepth, funcdepth);
+		}
+
+		// should only get here for heap vars or paramref
+		if(!(n->class & PHEAP) && n->class != PPARAMREF) {
+			dump("bad agen", n);
 			fatal("agen: bad ONAME class %#x", n->class);
+		}
 		cgen(n->heapaddr, res);
 		if(n->xoffset != 0) {
 			nodconst(&n1, types[TINT64], n->xoffset);

src/cmd/gc/dcl.c

@@ -402,13 +402,12 @@ funchdr(Node *n)
 	autodcl = dcl();
 	autodcl->back = autodcl;
 
-	if(dclcontext != PEXTERN)
+	if(funcdepth == 0 && dclcontext != PEXTERN)
 		fatal("funchdr: dclcontext");
 
 	dclcontext = PAUTO;
 	markdcl();
 	funcargs(n->type);
-
 }
 
 void
@@ -418,6 +417,8 @@ funcargs(Type *ft)
 	Iter save;
 	int all;
 
+	funcdepth++;
+
 	// declare the this/in arguments
 	t = funcfirst(&save, ft);
 	while(t != T) {
@@ -466,9 +467,176 @@ funcbody(Node *n)
 	if(dclcontext != PAUTO)
 		fatal("funcbody: dclcontext");
 	popdcl();
+	funcdepth--;
+	if(funcdepth == 0)
 		dclcontext = PEXTERN;
 }
 
+void
+funclit0(Type *t)
+{
+	Node *n;
+
+	n = nod(OXXX, N, N);
+	n->outer = funclit;
+	funclit = n;
+
+	funcargs(t);
+}
+
+Node*
+funclit1(Type *type, Node *body)
+{
+	Node *func;
+	Node *a, *d, *f, *n, *args, *clos, *in, *out;
+	Type *ft, *t;
+	Iter save;
+	int narg, shift;
+
+	popdcl();
+	func = funclit;
+	funclit = func->outer;
+
+	// build up type of func f that we're going to compile.
+	// as we referred to variables from the outer function,
+	// we accumulated a list of PHEAP names in func.
+	//
+	narg = 0;
+	if(func->cvars == N)
+		ft = type;
+	else {
+		// add PHEAP versions as function arguments.
+		in = N;
+		for(a=listfirst(&save, &func->cvars); a; a=listnext(&save)) {
+			d = nod(ODCLFIELD, a, N);
+			d->type = ptrto(a->type);
+			in = list(in, d);
+
+			// while we're here, set up a->heapaddr for back end
+			n = nod(ONAME, N, N);
+			snprint(namebuf, sizeof namebuf, "&%s", a->sym->name);
+			n->sym = lookup(namebuf);
+			n->type = ptrto(a->type);
+			n->class = PPARAM;
+			n->xoffset = narg*types[tptr]->width;
+			n->addable = 1;
+			n->ullman = 1;
+			narg++;
+			a->heapaddr = n;
+
+			a->xoffset = 0;
+
+			// unlink from actual ONAME in symbol table
+			a->closure->closure = a->outer;
+		}
+
+		// add a dummy arg for the closure's caller pc
+		d = nod(ODCLFIELD, a, N);
+		d->type = types[TUINTPTR];
+		in = list(in, d);
+
+		// slide param offset to make room for ptrs above.
+		// narg+1 to skip over caller pc.
+		shift = (narg+1)*types[tptr]->width;
+
+		// now the original arguments.
+		for(t=structfirst(&save, getinarg(type)); t; t=structnext(&save)) {
+			d = nod(ODCLFIELD, t->nname, N);
+			d->type = t->type;
+			in = list(in, d);
+
+			a = t->nname;
+			if(a != N) {
+				if(a->stackparam != N)
+					a = a->stackparam;
+				a->xoffset += shift;
+			}
+		}
+		in = rev(in);
+
+		// out arguments
+		out = N;
+		for(t=structfirst(&save, getoutarg(type)); t; t=structnext(&save)) {
+			d = nod(ODCLFIELD, t->nname, N);
+			d->type = t->type;
+			out = list(out, d);
+
+			a = t->nname;
+			if(a != N) {
+				if(a->stackparam != N)
+					a = a->stackparam;
+				a->xoffset += shift;
+			}
+		}
+		out = rev(out);
+
+		ft = functype(N, in, out);
+	}
+
+	// declare function.
+	vargen++;
+	snprint(namebuf, sizeof(namebuf), "_f%.3ld", vargen);
+	f = newname(lookup(namebuf));
+	addvar(f, ft, PFUNC);
+	f->funcdepth = 0;
+
+	// compile function
+	n = nod(ODCLFUNC, N, N);
+	n->nname = f;
+	n->type = ft;
+	if(body == N)
+		body = nod(ORETURN, N, N);
+	n->nbody = body;
+	compile(n);
+	funcdepth--;
+
+	// if there's no closure, we can use f directly
+	if(func->cvars == N)
+		return f;
+
+	// build up type for this instance of the closure func.
+	in = N;
+	d = nod(ODCLFIELD, N, N);	// siz
+	d->type = types[TINT];
+	in = list(in, d);
+	d = nod(ODCLFIELD, N, N);	// f
+	d->type = ft;
+	in = list(in, d);
+	for(a=listfirst(&save, &func->cvars); a; a=listnext(&save)) {
+		d = nod(ODCLFIELD, N, N);	// arg
+		d->type = ptrto(a->type);
+		in = list(in, d);
+	}
+	in = rev(in);
+
+	d = nod(ODCLFIELD, N, N);
+	d->type = type;
+	out = d;
+
+	clos = syslook("closure", 1);
+	clos->type = functype(N, in, out);
+
+	// literal expression is sys.closure(siz, f, arg0, arg1, ...)
+	// which builds a function that calls f after filling in arg0,
+	// arg1, ... for the PHEAP arguments above.
+	args = N;
+	if(narg*8 > 100)
+		yyerror("closure needs too many variables; runtime will reject it");
+	a = nodintconst(narg*8);
+	args = list(args, a);	// siz
+	args = list(args, f);	// f
+	for(a=listfirst(&save, &func->cvars); a; a=listnext(&save)) {
+		d = oldname(a->sym);
+		addrescapes(d);
+		args = list(args, nod(OADDR, d, N));
+	}
+	args = rev(args);
+
+	return nod(OCALL, clos, args);
+}
+
+
+
 /*
  * turn a parsed struct into a type
  */
@@ -657,28 +825,6 @@ markdcl(void)
 //		print("markdcl\n");
 }
 
-void
-markdclstack(void)
-{
-	Sym *d, *s;
-
-	markdcl();
-
-	// copy the entire pop of the stack
-	// all the way back to block0.
-	// after this the symbol table is at
-	// block0 and popdcl will restore it.
-	for(d=dclstack; d!=S; d=d->link) {
-		if(d == b0stack)
-			break;
-		if(d->name != nil) {
-			s = pkglookup(d->name, d->package);
-			pushdcl(s);
-			dcopy(s, d);
-		}
-	}
-}
-
 void
 dumpdcl(char *st)
 {
@@ -755,6 +901,7 @@ addvar(Node *n, Type *t, int ctxt)
 	s->offset = 0;
 	s->lexical = LNAME;
 
+	n->funcdepth = funcdepth;
 	n->type = t;
 	n->vargen = gen;
 	n->class = ctxt;
@@ -909,6 +1056,7 @@ Node*
 oldname(Sym *s)
 {
 	Node *n;
+	Node *c;
 
 	n = s->oname;
 	if(n == N) {
@@ -918,6 +1066,26 @@ oldname(Sym *s)
 		n->addable = 1;
 		n->ullman = 1;
 	}
+	if(n->funcdepth > 0 && n->funcdepth != funcdepth) {
+		// inner func is referring to var
+		// in outer func.
+		if(n->closure == N || n->closure->funcdepth != funcdepth) {
+			// create new closure var.
+			c = nod(ONAME, N, N);
+			c->sym = s;
+			c->class = PPARAMREF;
+			c->type = n->type;
+			c->addable = 0;
+			c->ullman = 2;
+			c->funcdepth = funcdepth;
+			c->outer = n->closure;
+			n->closure = c;
+			c->closure = n;
+			funclit->cvars = list(c, funclit->cvars);
+		}
+		// return ref to closure var, not original
+		return n->closure;
+	}
 	return n;
 }
 

src/cmd/gc/go.h

@@ -187,6 +187,7 @@ struct	Node
 	uchar	colas;		// OAS resulting from :=
 	uchar	diag;		// already printed error about this
 	uchar	noescape;	// ONAME never move to heap
+	uchar	funcdepth;
 
 	// most nodes
 	Node*	left;
@@ -209,6 +210,7 @@ struct	Node
 	Node*	nname;
 	Node*	enter;
 	Node*	exit;
+	Node*	cvars;	// closure params
 
 	// OLITERAL/OREGISTER
 	Val	val;
@@ -218,6 +220,10 @@ struct	Node
 	Node*	stackparam;	// OPARAM node referring to stack copy of param
 	Node*	alloc;	// allocation call
 
+	// ONAME closure param with PPARAMREF
+	Node*	outer;	// outer PPARAMREF in nested closure
+	Node*	closure;	// ONAME/PHEAP <-> ONAME/PPARAMREF
+
 	Sym*	osym;		// import
 	Sym*	psym;		// import
 	Sym*	sym;		// various
@@ -414,6 +420,7 @@ enum
 	PAUTO,
 	PPARAM,
 	PPARAMOUT,
+	PPARAMREF,	// param passed by reference
 	PFUNC,
 
 	PHEAP = 1<<7,
@@ -527,6 +534,10 @@ EXTERN	int32	thunk;
 
 EXTERN	int	exporting;
 
+EXTERN	int	funcdepth;
+
+EXTERN	Node*	funclit;
+
 /*
  *	y.tab.c
  */
@@ -750,6 +761,9 @@ Node*	embedded(Sym*);
 Node*	variter(Node*, Type*, Node*);
 void	constiter(Node*, Type*, Node*);
 
+void	funclit0(Type*);
+Node*	funclit1(Type*, Node*);
+
 /*
  *	export.c
  */

src/cmd/gc/go.y

@@ -1245,33 +1245,15 @@ Bfntype:
 fnlitdcl:
 	fntype
 	{
-		markdclstack();	// save dcl stack and revert to block0
+		markdcl();
 		$$ = $1;
-		funcargs($$);
+		funclit0($$);
 	}
 
 fnliteral:
 	fnlitdcl '{' ostmt_list '}'
 	{
-		popdcl();
-
-		vargen++;
-		snprint(namebuf, sizeof(namebuf), "_f%.3ld", vargen);
-
-		$$ = newname(lookup(namebuf));
-		addvar($$, $1, PFUNC);
-
-		{
-			Node *n;
-
-			n = nod(ODCLFUNC, N, N);
-			n->nname = $$;
-			n->type = $1;
-			n->nbody = $3;
-			if(n->nbody == N)
-				n->nbody = nod(ORETURN, N, N);
-			compile(n);
-		}
+		$$ = funclit1($1, $3);
 	}
 
 fnbody:

src/cmd/gc/subr.c

@@ -880,6 +880,11 @@ Jconv(Fmt *fp)
 		strncat(buf, buf1, sizeof(buf));
 	}
 
+	if(n->xoffset != 0) {
+		snprint(buf1, sizeof(buf1), " x(%lld)", n->xoffset);
+		strncat(buf, buf1, sizeof(buf));
+	}
+
 	if(n->class != 0) {
 		snprint(buf1, sizeof(buf1), " class(%d)", n->class);
 		strncat(buf, buf1, sizeof(buf));
@@ -890,6 +895,12 @@ Jconv(Fmt *fp)
 		strncat(buf, buf1, sizeof(buf));
 	}
 
+	if(n->funcdepth != 0) {
+		snprint(buf1, sizeof(buf1), " f(%d)", n->funcdepth);
+		strncat(buf, buf1, sizeof(buf));
+	}
+
+
 	return fmtstrcpy(fp, buf);
 }
 
@@ -2070,6 +2081,8 @@ ullmancalc(Node *n)
 	case OLITERAL:
 	case ONAME:
 		ul = 1;
+		if(n->class == PPARAMREF || (n->class & PHEAP))
+			ul++;
 		goto out;
 	case OCALL:
 	case OCALLMETH:

src/cmd/gc/sys.go

@@ -67,6 +67,8 @@ func	arraysliced(old []any, lb int, hb int, width int) (ary []any);
 func	arrayslices(old *any, nel int, lb int, hb int, width int) (ary []any);
 func	arrays2d(old *any, nel int) (ary []any);
 
+func	closure();	// has args, but compiler fills in
+
 // used by go programs
 
 func	Breakpoint();

src/cmd/gc/sysimport.c

@@ -50,6 +50,7 @@ char *sysimport =
 	"func sys.arraysliced (old []any, lb int, hb int, width int) (ary []any)\n"
 	"func sys.arrayslices (old *any, nel int, lb int, hb int, width int) (ary []any)\n"
 	"func sys.arrays2d (old *any, nel int) (ary []any)\n"
+	"func sys.closure ()\n"
 	"func sys.Breakpoint ()\n"
 	"func sys.Reflect (i interface { }) (? uint64, ? string, ? bool)\n"
 	"func sys.Unreflect (? uint64, ? string, ? bool) (ret interface { })\n"

src/cmd/gc/walk.c

@@ -294,7 +294,7 @@ loop:
 	case ONAME:
 		if(top == Etop)
 			goto nottop;
-		if(!(n->class & PHEAP))
+		if(!(n->class & PHEAP) && n->class != PPARAMREF)
 			n->addable = 1;
 		if(n->type == T) {
 			s = n->sym;
@@ -2022,7 +2022,10 @@ loop:
 			argtype(on, l->type);		// any-1
 			break;
 		}
-		if(isptr[l->type->etype] || l->type->etype == TCHAN || l->type->etype == TMAP) {
+		if(isptr[l->type->etype]
+		|| l->type->etype == TCHAN
+		|| l->type->etype == TMAP
+		|| l->type->etype == TFUNC) {
 			on = syslook("printpointer", 1);
 			argtype(on, l->type);	// any-1
 			break;
@@ -3668,22 +3671,22 @@ addrescapes(Node *n)
 		case PPARAM:
 			if(debug['E'])
 				print("%L %s %S escapes %p\n", n->lineno, pnames[n->class], n->sym, n);
-			n->class |= PHEAP;
-			n->addable = 0;
-			n->ullman = 2;
-			n->alloc = callnew(n->type);
-
 			// if func param, need separate temporary
 			// to hold heap pointer.
-			if(n->class == PPARAM+PHEAP) {
+			if(n->class == PPARAM) {
 				// expression to refer to stack copy
 				n->stackparam = nod(OPARAM, n, N);
 				n->stackparam->type = n->type;
 				n->stackparam->addable = 1;
 				n->stackparam->xoffset = n->xoffset;
-				n->xoffset = 0;
 			}
 
+			n->class |= PHEAP;
+			n->addable = 0;
+			n->ullman = 2;
+			n->alloc = callnew(n->type);
+			n->xoffset = 0;
+
 			// create stack variable to hold pointer to heap
 			n->heapaddr = nod(0, N, N);
 			tempname(n->heapaddr, ptrto(n->type));
@@ -3721,9 +3724,7 @@ paramstoheap(Type **argin)
 
 	nn = N;
 	for(t = structfirst(&savet, argin); t != T; t = structnext(&savet)) {
-		if(t->sym == S)
-			continue;
-		v = t->sym->oname;
+		v = t->nname;
 		if(v == N || !(v->class & PHEAP))
 			continue;