cleanup in preparation for new scoping.

walkstate -> walkstmt
walktype -> walkexpr; stmts moved to walkstmt

walktype and friends have a final Node **init
argument that can have side effects appended,
making it more explicit when they do and do not happen.
this replaces the old global addtop and addtotop.

delete switch map and interface conversion cases
(dropped from the language months ago).

R=ken
OCL=31465
CL=31468

src/cmd/gc/dcl.c

@@ -17,8 +17,12 @@ dflag(void)
 	return 1;
 }
 
+/*
+ * declare (possible list) n of type t.
+ * append ODCL nodes to *init
+ */
 void
-dodclvar(Node *n, Type *t)
+dodclvar(Node *n, Type *t, Node **init)
 {
 	if(n == N)
 		return;
@@ -26,7 +30,7 @@ dodclvar(Node *n, Type *t)
 	if(t != T && (t->etype == TIDEAL || t->etype == TNIL))
 		fatal("dodclvar %T", t);
 	for(; n->op == OLIST; n = n->right)
-		dodclvar(n->left, t);
+		dodclvar(n->left, t, init);
 
 	dowidth(t);
 
@@ -39,7 +43,7 @@ dodclvar(Node *n, Type *t)
 	addvar(n, t, dclcontext);
 	autoexport(n->sym);
 	if(funcdepth > 0)
-		addtop = list(addtop, nod(ODCL, n, N));
+		*init = list(*init, nod(ODCL, n, N));
 }
 
 void
@@ -1665,13 +1669,14 @@ embedded(Sym *s)
 
 /*
  * declare variables from grammar
- * new_name_list [type] = expr_list
+ * new_name_list (type | [type] = expr_list)
  */
 Node*
 variter(Node *vv, Type *t, Node *ee)
 {
 	Iter viter, eiter;
 	Node *v, *e, *r, *a;
+	Type *tv;
 
 	vv = rev(vv);
 	ee = rev(ee);
@@ -1680,29 +1685,31 @@ variter(Node *vv, Type *t, Node *ee)
 	e = listfirst(&eiter, &ee);
 	r = N;
 
-loop:
-	if(v == N && e == N)
-		return rev(r);
-
-	if(v == N || e == N) {
-		yyerror("shape error in var dcl");
-		return rev(r);
-	}
-
-	a = nod(OAS, v, N);
-	if(t == T) {
-		gettype(e, a);
-		defaultlit(e, T);
-		dodclvar(v, e->type);
-	} else
-		dodclvar(v, t);
-	a->right = e;
+	while(v != N) {
+		if(ee != N && e == N) {
+			yyerror("missing expr in var dcl");
+			break;
+		}
 
-	r = list(r, a);
+		a = N;
+		if(e != N || funcdepth > 0)
+			a = nod(OAS, v, e);
+		tv = t;
+		if(t == T) {
+			gettype(e, &r);
+			defaultlit(e, T);
+			tv = e->type;
+		}
+		dodclvar(v, tv, &r);
+		r = list(r, a);
 
-	v = listnext(&viter);
-	e = listnext(&eiter);
-	goto loop;
+		v = listnext(&viter);
+		if(ee != N)
+			e = listnext(&eiter);
+	}
+	if(e != N)
+		yyerror("extra expr in var dcl");
+	return rev(r);
 }
 
 /*
@@ -1713,7 +1720,7 @@ void
 constiter(Node *vv, Type *t, Node *cc)
 {
 	Iter viter, citer;
-	Node *v, *c, n1;
+	Node *v, *c, *init;
 
 	if(cc == N) {
 		if(t != T)
@@ -1741,9 +1748,9 @@ loop:
 		return;
 	}
 
-	memset(&n1, 0, sizeof n1);
-	gettype(c, &n1);
-	if(n1.ninit != nil) {
+	init = N;
+	gettype(c, &init);
+	if(init != N) {
 		// the expression had extra code to run.
 		// dodclconst is going to print an error
 		// because the expression isn't constant,
@@ -1771,7 +1778,7 @@ loop:
 Node*
 unsafenmagic(Node *l, Node *r)
 {
-	Node *n;
+	Node *n, *init;
 	Sym *s;
 	Type *t, *tr;
 	long v;
@@ -1787,8 +1794,9 @@ unsafenmagic(Node *l, Node *r)
 	if(strcmp(s->package, "unsafe") != 0)
 		goto no;
 
+	init = N;
 	if(strcmp(s->name, "Sizeof") == 0) {
-		walktype(r, Erv);
+		walkexpr(r, Erv, &init);
 		tr = r->type;
 		if(r->op == OLITERAL && r->val.ctype == CTSTR)
 			tr = types[TSTRING];
@@ -1800,12 +1808,12 @@ unsafenmagic(Node *l, Node *r)
 	if(strcmp(s->name, "Offsetof") == 0) {
 		if(r->op != ODOT && r->op != ODOTPTR)
 			goto no;
-		walktype(r, Erv);
+		walkexpr(r, Erv, &init);
 		v = r->xoffset;
 		goto yes;
 	}
 	if(strcmp(s->name, "Alignof") == 0) {
-		walktype(r, Erv);
+		walkexpr(r, Erv, &init);
 		tr = r->type;
 		if(r->op == OLITERAL && r->val.ctype == CTSTR)
 			tr = types[TSTRING];
@@ -1830,7 +1838,7 @@ no:
 	return N;
 
 yes:
-	addtop = N;	// any side effects disappear
+	// any side effects disappear; ignore init
 	val.ctype = CTINT;
 	val.u.xval = mal(sizeof(*n->val.u.xval));
 	mpmovecfix(val.u.xval, v);

src/cmd/gc/go.h

@@ -601,7 +601,6 @@ EXTERN	int	widthptr;
 EXTERN	Node*	retnil;
 EXTERN	Node*	fskel;
 
-EXTERN	Node*	addtop;
 EXTERN	Node*	typeswvar;
 
 EXTERN	char*	structpkg;
@@ -765,7 +764,7 @@ void	tempname(Node*, Type*);
 Node*	staticname(Type*);
 int	iscomposite(Type*);
 Node*	callnew(Type*);
-Node*	saferef(Node*);
+Node*	saferef(Node*, Node**);
 int	is64(Type*);
 int	noconv(Type*, Type*);
 
@@ -812,7 +811,7 @@ int	simsimtype(Type*);
 /*
  *	dcl.c
  */
-void	dodclvar(Node*, Type*);
+void	dodclvar(Node*, Type*, Node**);
 Type*	dodcltype(Type*);
 void	updatetype(Type*, Type*);
 void	dodclconst(Node*, Node*);
@@ -907,30 +906,29 @@ Type*	pkgtype(Sym*);
 /*
  *	walk.c
  */
-void	addtotop(Node*);
-void	gettype(Node*, Node*);
+void	gettype(Node*, Node**);
 void	walk(Node*);
-void	walkstate(Node*);
-void	walktype(Node*, int);
-void	walkconv(Node*);
+void	walkstmt(Node*);
+void	walkexpr(Node*, int, Node**);
+void	walkconv(Node*, Node**);
 void	walkas(Node*);
 void	walkbool(Node*);
 void	walkswitch(Node*);
 void	walkselect(Node*);
-void	walkdot(Node*);
-Node*	ascompatee(int, Node**, Node**);
-Node*	ascompatet(int, Node**, Type**, int);
-Node*	ascompatte(int, Type**, Node**, int);
+void	walkdot(Node*, Node**);
+Node*	ascompatee(int, Node**, Node**, Node**);
+Node*	ascompatet(int, Node**, Type**, int, Node**);
+Node*	ascompatte(int, Type**, Node**, int, Node**);
 int	ascompat(Type*, Type*);
 Node*	prcompat(Node*, int);
 Node*	nodpanic(int32);
 Node*	newcompat(Node*);
 Node*	makecompat(Node*);
-Node*	stringop(Node*, int);
+Node*	stringop(Node*, int, Node**);
 Type*	fixmap(Type*);
-Node*	mapop(Node*, int);
+Node*	mapop(Node*, int, Node**);
 Type*	fixchan(Type*);
-Node*	chanop(Node*, int);
+Node*	chanop(Node*, int, Node**);
 Node*	arrayop(Node*, int);
 Node*	ifacecvt(Type*, Node*, int);
 Node*	ifaceop(Node*);
@@ -938,18 +936,18 @@ int	ifaceas(Type*, Type*, int);
 int	ifaceas1(Type*, Type*, int);
 void	ifacecheck(Type*, Type*, int, int);
 void	runifacechecks(void);
-Node*	convas(Node*);
+Node*	convas(Node*, Node**);
 void	arrayconv(Type*, Node*);
-Node*	colas(Node*, Node*);
+Node*	colas(Node*, Node*, Node**);
 Node*	dorange(Node*);
 Node*	reorder1(Node*);
 Node*	reorder3(Node*);
 Node*	reorder4(Node*);
-Node*	structlit(Node*, Node*);
-Node*	arraylit(Node*, Node*);
-Node*	maplit(Node*, Node*);
-Node*	selectas(Node*, Node*);
-Node*	old2new(Node*, Type*);
+Node*	structlit(Node*, Node*, Node**);
+Node*	arraylit(Node*, Node*, Node**);
+Node*	maplit(Node*, Node*, Node**);
+Node*	selectas(Node*, Node*, Node**);
+Node*	old2new(Node*, Type*, Node**);
 void	addrescapes(Node*);
 void	heapmoves(void);
 

src/cmd/gc/go.y

@@ -351,30 +351,15 @@ varoptsemi:
 vardcl:
 	name_list type varoptsemi
 	{
-		dodclvar($$, $2);
-
-		if(funcdepth == 0) {
-			$$ = N;
-		} else {
-			$$ = nod(OAS, $$, N);
-			addtotop($$);
-		}
+		$$ = variter($1, $2, N);
 	}
 |	name_list type varoptsemi '=' expr_list
 	{
-		if(addtop != N)
-			fatal("new_name_list_r type '=' expr_list");
-
 		$$ = variter($1, $2, $5);
-		addtotop($$);
 	}
 |	name_list '=' expr_list
 	{
-		if(addtop != N)
-			fatal("new_name_list_r '=' expr_list");
-
 		$$ = variter($1, T, $3);
-		addtotop($$);
 	}
 
 constdcl:
@@ -438,16 +423,17 @@ simple_stmt:
 	}
 |	expr_list LCOLAS expr_list
 	{
-		if(addtop != N)
-			fatal("expr_list LCOLAS expr_list");
+		Node *top;
+
 		if($3->op == OTYPESW) {
 			$$ = nod(OTYPESW, $1, $3->left);
 			break;
 		}
-		$$ = colas($$, $3);
+		top = N;
+		$$ = colas($$, $3, &top);
 		$$ = nod(OAS, $$, $3);
 		$$->colas = 1;
-		addtotop($$);
+		$$->ninit = top;
 	}
 |	expr LINC
 	{
@@ -463,9 +449,12 @@ simple_stmt:
 case:
 	LCASE expr_list ':'
 	{
+		Node *top;
+
 		// will be converted to OCASE
 		// right will point to next case
 		// done in casebody()
+		top = N;
 		poptodcl();
 		if(typeswvar != N && typeswvar->right != N) {
 			int e;
@@ -476,14 +465,14 @@ case:
 				break;
 			}
 			if($2->op == OTYPE) {
-				$$ = old2new(typeswvar->right, $2->type);
+				$$ = old2new(typeswvar->right, $2->type, &top);
 				$$ = nod(OTYPESW, $$, N);
 				$$ = nod(OXCASE, $$, N);
-				addtotop($$);
+				$$->ninit = top;
 				break;
 			}
 			e = nerrors;
-			gettype($2, N);
+			gettype($2, nil);
 			// maybe gettype found problems that keep
 			// e from being valid even outside a type switch.
 			// only complain if gettype didn't print new errors.
@@ -497,15 +486,18 @@ case:
 	}
 |	LCASE type ':'
 	{
+		Node *top;
+
+		top = N;
 		poptodcl();
 		if(typeswvar == N || typeswvar->right == N) {
 			yyerror("type case not in a type switch");
 			$$ = N;
 		} else
-			$$ = old2new(typeswvar->right, $2);
+			$$ = old2new(typeswvar->right, $2, &top);
 		$$ = nod(OTYPESW, $$, N);
 		$$ = nod(OXCASE, $$, N);
-		addtotop($$);
+		$$->ninit = top;
 	}
 |	LCASE name '=' expr ':'
 	{
@@ -518,13 +510,16 @@ case:
 	}
 |	LCASE name LCOLAS expr ':'
 	{
+		Node *top;
+
 		// will be converted to OCASE
 		// right will point to next case
 		// done in casebody()
 		poptodcl();
-		$$ = nod(OAS, selectas($2,$4), $4);
+		top = N;
+		$$ = nod(OAS, selectas($2, $4, &top), $4);
 		$$ = nod(OXCASE, $$, N);
-		addtotop($$);
+		$$->ninit = top;
 	}
 |	LDEFAULT ':'
 	{
@@ -621,7 +616,6 @@ for_header:
 |	range_stmt
 	{
 		$$ = dorange($1);
-		addtotop($$);
 	}
 
 for_body:

src/cmd/gc/sinit.c

@@ -249,7 +249,7 @@ mapindex(Node *n)
 	b = nod(OAS, b, val);
 
 	a = nod(OLIST, a, b);
-	walktype(a, Etop);
+	walkexpr(a, Etop, nil);
 
 	return a;
 }

src/cmd/gc/subr.c

@@ -517,11 +517,13 @@ appendr(Node *na, Node *nb)
 Type*
 aindex(Node *b, Type *t)
 {
+	Node *top;
 	Type *r;
 	int bound;
 
 	bound = -1;	// open bound
-	walktype(b, Erv);
+	top = N;
+	walkexpr(b, Erv, &top);
 	if(b != nil) {
 		switch(consttype(b)) {
 		default:
@@ -2452,25 +2454,26 @@ staticname(Type *t)
 }
 
 /*
- * return side effect-free n, moving side effects to top.
+ * return side effect-free n, appending side effects to init.
  */
 Node*
-saferef(Node *n)
+saferef(Node *n, Node **init)
 {
 	Node *l;
 	Node *r;
+	Node *a;
 
 	switch(n->op) {
 	case ONAME:
 		return n;
 	case ODOT:
-		l = saferef(n->left);
+		l = saferef(n->left, init);
 		if(l == n->left)
 			return n;
 		r = nod(OXXX, N, N);
 		*r = *n;
 		r->left = l;
-		walktype(r, Elv);
+		walkexpr(r, Elv, init);
 		return r;
 
 	case OINDEX:
@@ -2478,9 +2481,11 @@ saferef(Node *n)
 	case OIND:
 		l = nod(OXXX, N, N);
 		tempname(l, ptrto(n->type));
-		addtop = list(addtop, nod(OAS, l, nod(OADDR, n, N)));
+		a = nod(OAS, l, nod(OADDR, n, N));
+		walkexpr(a, Etop, init);
+		*init = list(*init, a);
 		r = nod(OIND, l, N);
-		walktype(r, Elv);
+		walkexpr(r, Elv, init);
 		return r;
 	}
 	fatal("saferef %N", n);
@@ -2634,11 +2639,13 @@ out:
 Node*
 adddot(Node *n)
 {
+	Node *top;
 	Type *t;
 	Sym *s;
 	int c, d;
 
-	walktype(n->left, Erv);
+	top = N;
+	walkexpr(n->left, Erv, &top);
 	t = n->left->type;
 	if(t == T)
 		goto ret;
@@ -2666,8 +2673,8 @@ out:
 		n->left->right = newname(dotlist[c].field->sym);
 	}
 ret:
-	n->ninit = list(addtop, n->ninit);
-	addtop = N;
+	if(top != N)
+		n->ninit = list(top, n->ninit);
 	return n;
 }
 

src/cmd/gc/swt.c

@@ -247,7 +247,7 @@ sw0(Node *c, Type *place, int arg)
 			yyerror("inappropriate case for a type switch");
 			return T;
 		}
-		walktype(c, Erv);
+		walkexpr(c, Erv, nil);
 		break;
 	case OTYPESW:
 		if(arg != Stype)
@@ -298,7 +298,7 @@ sw3(Node *c, Type *place, int arg)
 }
 
 /*
- * over all cases, call paramenter function.
+ * over all cases, call parameter function.
  * four passes of these are used to allocate
  * types to cases and switch
  */
@@ -335,7 +335,7 @@ loop:
 }
 
 Node*
-newlabel()
+newlabel(void)
 {
 	static int label;
 
@@ -598,7 +598,7 @@ exprswitch(Node *sw)
 		if(sw->ntest->val.u.bval == 0)
 			arg = Sfalse;
 	}
-	walktype(sw->ntest, Erv);
+	walkexpr(sw->ntest, Erv, &sw->ninit);
 
 	/*
 	 * pass 0,1,2,3
@@ -639,7 +639,7 @@ loop:
 	if(c0 == C) {
 		cas = list(cas, def);
 		sw->nbody->left = rev(cas);
-		walkstate(sw->nbody);
+		walkstmt(sw->nbody);
 		return;
 	}
 
@@ -773,7 +773,7 @@ typeswitch(Node *sw)
 		yyerror("type switch must have an assignment");
 		return;
 	}
-	walktype(sw->ntest->right, Erv);
+	walkexpr(sw->ntest->right, Erv, &sw->ninit);
 	if(!istype(sw->ntest->right->type, TINTER)) {
 		yyerror("type switch must be on an interface");
 		return;
@@ -818,7 +818,7 @@ loop:
 	if(c0 == C) {
 		cas = list(cas, def);
 		sw->nbody->left = rev(cas);
-		walkstate(sw->nbody);
+		walkstmt(sw->nbody);
 		return;
 	}
 
@@ -860,7 +860,7 @@ walkswitch(Node *sw)
 	 * cases have OGOTO into statements.
 	 * both have inserted OBREAK statements
 	 */
-	walkstate(sw->ninit);
+	walkstmt(sw->ninit);
 	if(sw->ntest == N)
 		sw->ntest = nodbool(1);
 	casebody(sw);