bug157

R=ken
OCL=29651
CL=29653

3 files changed, 190 insertions, 166 deletions

diff --git a/src/cmd/gc/go.y b/src/cmd/gc/go.y
index 374b671b6..cc9caf926 100644
--- a/src/cmd/gc/go.y
+++ b/src/cmd/gc/go.y
@@ -47,11 +47,11 @@
 %type	<node>		common_dcl Acommon_dcl Bcommon_dcl
 %type	<node>		oarg_type_list arg_type_list_r arg_chunk arg_chunk_list_r arg_type_list
 %type	<node>		Aelse_stmt Belse_stmt
-%type	<node>		complex_stmt compound_stmt ostmt_list
-%type	<node>		stmt_list_r Astmt_list_r Bstmt_list_r
+%type	<node>		complex_stmt compound_stmt switch_body ocaseblock_list ostmt_list
+%type	<node>		caseblock_list_r stmt_list_r Astmt_list_r Bstmt_list_r
 %type	<node>		Astmt Bstmt
 %type	<node>		for_stmt for_body for_header
-%type	<node>		if_stmt if_body if_header select_stmt condition
+%type	<node>		if_stmt if_header select_stmt switch_stmt condition case caseblock
 %type	<node>		simple_stmt osimple_stmt range_stmt semi_stmt
 %type	<node>		expr uexpr pexpr expr_list oexpr oexpr_list expr_list_r
 %type	<node>		exprsym3_list_r exprsym3 pseudocall
@@ -511,34 +511,23 @@ simple_stmt:
 	}
 
 complex_stmt:
-	LFOR for_stmt
+	for_stmt
+|	switch_stmt
+|	select_stmt
+|	if_stmt
 	{
 		popdcl();
-		$$ = $2;
-	}
-|	LSWITCH if_stmt
-	{
-		popdcl();
-		$$ = $2;
-		$$->op = OSWITCH;
-	}
-|	LIF if_stmt
-	{
-		popdcl();
-		$$ = $2;
-	}
-|	LIF if_stmt LELSE Aelse_stmt
-	{
-		popdcl();
-		$$ = $2;
-		$$->nelse = $4;
+		$$ = $1;
 	}
-|	LSELECT select_stmt
+|	if_stmt LELSE Aelse_stmt
 	{
 		popdcl();
-		$$ = $2;
+		$$ = $1;
+		$$->nelse = $3;
 	}
-|	LCASE expr_list ':'
+
+case:
+	LCASE expr_list ':'
 	{
 		// will be converted to OCASE
 		// right will point to next case
@@ -620,11 +609,11 @@ semi_stmt:
 	{
 		$$ = nod(ORETURN, $2, N);
 	}
-|	LIF if_stmt LELSE Belse_stmt
+|	if_stmt LELSE Belse_stmt
 	{
 		popdcl();
-		$$ = $2;
-		$$->nelse = $4;
+		$$ = $1;
+		$$->nelse = $3;
 	}
 
 compound_stmt:
@@ -639,6 +628,33 @@ compound_stmt:
 		popdcl();
 	}
 
+switch_body:
+	'{'
+	{
+		markdcl();
+	}
+	ocaseblock_list '}'
+	{
+		$$ = $3;
+		if($$ == N)
+			$$ = nod(OEMPTY, N, N);
+		popdcl();
+	}
+
+caseblock:
+	case ostmt_list
+	{
+		$$ = $1;
+		$$->nbody = $2;
+	}
+
+caseblock_list_r:
+	caseblock
+|	caseblock_list_r caseblock
+	{
+		$$ = nod(OLIST, $1, $2);
+	}
+
 range_stmt:
 	exprsym3_list_r '=' LRANGE expr
 	{
@@ -684,11 +700,14 @@ for_body:
 	}
 
 for_stmt:
+	LFOR
 	{
 		markdcl();
-	} for_body
+	}
+	for_body
 	{
-		$$ = $2;
+		$$ = $3;
+		popdcl();
 	}
 
 /*
@@ -722,38 +741,51 @@ if_header:
 		$$->ntest = $3;
 	}
 
-if_body:
+if_stmt:
+	LIF
+	{
+		markdcl();
+	}
+	if_header compound_stmt
+	{
+		$$ = $3;
+		$$->nbody = $4;
+		// no popdcl; maybe there's an LELSE
+	}
+
+switch_stmt:
+	LSWITCH
+	{
+		markdcl();
+	}
 	if_header
 	{
 		Node *n;
-		n = $1->ntest;
+		n = $3->ntest;
 		if(n != N && n->op == OTYPESW)
 			n = n->left;
 		else
 			n = N;
 		typeswvar = nod(OLIST, typeswvar, n);
-	} compound_stmt
-	{
-		$$ = $1;
-		$$->nbody = $3;
-		typeswvar = typeswvar->left;
 	}
-
-if_stmt:
-	{
-		markdcl();
-	} if_body
+	switch_body
 	{
-		$$ = $2;
+		$$ = $3;
+		$$->op = OSWITCH;
+		$$->nbody = $5;
+		typeswvar = typeswvar->left;
+		popdcl();
 	}
 
 select_stmt:
+	LSELECT
 	{
 		markdcl();
 	}
-	compound_stmt
+	switch_body
 	{
-		$$ = nod(OSELECT, $2, N);
+		$$ = nod(OSELECT, $3, N);
+		popdcl();
 	}
 
 /*
@@ -1849,6 +1881,15 @@ ostmt_list:
 		$$ = rev($1);
 	}
 
+ocaseblock_list:
+	{
+		$$ = N;
+	}
+|	caseblock_list_r
+	{
+		$$ = rev($1);
+	}
+
 oxdcl_list:
 	{
 		$$ = N;
diff --git a/src/cmd/gc/swt.c b/src/cmd/gc/swt.c
index 318427636..486e181b1 100644
--- a/src/cmd/gc/swt.c
+++ b/src/cmd/gc/swt.c
@@ -348,8 +348,8 @@ newlabel()
 void
 casebody(Node *sw)
 {
-	Iter save;
-	Node *os, *oc, *n, *c;
+	Iter save, save1;
+	Node *os, *oc, *n, *n1, *c;
 	Node *cas, *stat, *def;
 	Node *go, *br;
 	int32 lno;
@@ -368,70 +368,56 @@ casebody(Node *sw)
 	oc = N;		// last case
 	br = nod(OBREAK, N, N);
 
-loop:
-	if(n == N) {
-		if(oc == N && os != N)
-			yyerror("first switch statement must be a case");
-
-		stat = list(stat, br);
-		cas = list(cas, def);
-
-		sw->nbody = nod(OLIST, rev(cas), rev(stat));
-//dump("case", sw->nbody->left);
-//dump("stat", sw->nbody->right);
-		lineno = lno;
-		return;
-	}
-
-	lno = setlineno(n);
-
-	if(n->op != OXCASE) {
-		stat = list(stat, n);
-		os = n;
-		goto next;
-	}
-
-	n->op = OCASE;
-	if(oc == N && os != N)
-		yyerror("first switch statement must be a case");
+	for(; n != N; n = listnext(&save)) {
+		lno = setlineno(n);
+		if(n->op != OXCASE)
+			fatal("casebody %O", n->op);
+		n->op = OCASE;
+
+		go = nod(OGOTO, newlabel(), N);
+		c = n->left;
+		if(c == N) {
+			if(def != N)
+				yyerror("more than one default case");
+			// reuse original default case
+			n->right = go;
+			def = n;
+		}
 
-	// botch - shouldnt fall thru declaration
-	if(os != N && os->op == OXFALL)
-		os->op = OFALL;
-	else
-		stat = list(stat, br);
+		// expand multi-valued cases
+		for(; c!=N; c=c->right) {
+			if(c->op != OLIST) {
+				// reuse original case
+				n->left = c;
+				n->right = go;
+				cas = list(cas, n);
+				break;
+			}
+			cas = list(cas, nod(OCASE, c->left, go));
+		}
 
-	go = nod(OGOTO, newlabel(), N);
+		stat = list(stat, nod(OLABEL, go->left, N));
 
-	c = n->left;
-	if(c == N) {
-		if(def != N)
-			yyerror("more than one default case");
+		os = N;
+		for(n1 = listfirst(&save1, &n->nbody); n1 != N; n1 = listnext(&save1)) {
+			os = n1;
+			stat = list(stat, n1);
+		}
 
-		// reuse original default case
-		n->right = go;
-		def = n;
+		// botch - shouldnt fall thru declaration
+		if(os != N && os->op == OXFALL)
+			os->op = OFALL;
+		else
+			stat = list(stat, br);
 	}
 
-	// expand multi-valued cases
-	for(; c!=N; c=c->right) {
-		if(c->op != OLIST) {
-			// reuse original case
-			n->left = c;
-			n->right = go;
-			cas = list(cas, n);
-			break;
-		}
-		cas = list(cas, nod(OCASE, c->left, go));
-	}
-	stat = list(stat, nod(OLABEL, go->left, N));
-	oc = n;
-	os = N;
-	goto next;
+	stat = list(stat, br);
+	cas = list(cas, def);
 
-next:
-	n = listnext(&save);
-	goto loop;
+	sw->nbody = nod(OLIST, rev(cas), rev(stat));
+//dump("case", sw->nbody->left);
+//dump("stat", sw->nbody->right);
+	lineno = lno;
 }
 
 Case*
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index f18227951..1cfac55af 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -1539,8 +1539,8 @@ bad:
 void
 walkselect(Node *sel)
 {
-	Iter iter;
-	Node *n, *l, *oc, *on, *r;
+	Iter iter, iter1;
+	Node *n, *n1, *l, *oc, *on, *r;
 	Node *var, *bod, *nbod, *res, *def;
 	int count, op;
 	int32 lno;
@@ -1552,8 +1552,10 @@ walkselect(Node *sel)
 	tempname(var, ptrto(types[TUINT8]));
 
 	n = listfirst(&iter, &sel->left);
-	if(n == N || n->op != OXCASE)
-		yyerror("first select statement must be a case");
+	if(n == N || n->op == OEMPTY) {
+		yyerror("empty select");
+		return;
+	}
 
 	count = 0;	// number of cases
 	res = N;	// entire select body
@@ -1563,72 +1565,67 @@ walkselect(Node *sel)
 
 	for(; n!=N; n=listnext(&iter)) {
 		setlineno(n);
+		if(n->op != OXCASE)
+			fatal("walkselect %O", n->op);
 
-		switch(n->op) {
+		count++;
+		if(n->left == N) {
+			op = ORECV;	// actual value not used
+			if(def != N)
+				yyerror("repeated default; first at %L", def->lineno);
+			def = n;
+		} else
+			op = n->left->op;
+
+		nbod = N;
+		switch(op) {
 		default:
-			bod = list(bod, n);
-			break;
+			yyerror("select cases must be send, recv or default");
+			continue;
 
-		case OXCASE:
-			if(n->left == N) {
-				op = ORECV;	// actual value not used
-				if(def != N)
-					yyerror("only one default select allowed");
-				def = n;
-			} else
-				op = n->left->op;
-			nbod = N;
-			switch(op) {
-			default:
+		case OAS:
+			// convert new syntax (a=recv(chan)) to (recv(a,chan))
+			l = n->left;
+			if(l->right == N || l->right->op != ORECV) {
 				yyerror("select cases must be send, recv or default");
 				break;
-
-			case OAS:
-				// convert new syntax (a=recv(chan)) to (recv(a,chan))
-				l = n->left;
-				if(l->right == N || l->right->op != ORECV) {
-					yyerror("select cases must be send, recv or default");
-					break;
-				}
-				r = l->right;	// rcv
-				r->right = r->left;
-				r->left = l->left;
-				n->left = r;
-
-				// convert case x := foo: body
-				// to case tmp := foo: x := tmp; body.
-				// if x escapes and must be allocated
-				// on the heap, this delays the allocation
-				// until after the select has chosen this branch.
-				if(n->ninit != N && n->ninit->op == ODCL) {
-					on = nod(OXXX, N, N);
-					tempname(on, l->left->type);
-					on->sym = lookup("!tmpselect!");
-					r->left = on;
-					nbod = nod(OAS, l->left, on);
-					nbod->ninit = n->ninit;
-					n->ninit = N;
-				}
-
-				// fall through
-			case OSEND:
-			case ORECV:
-				if(oc != N) {
-					bod = list(bod, nod(OBREAK, N, N));
-					oc->nbody = rev(bod);
-				}
-				oc = selcase(n, var);
-				res = list(res, oc);
-				break;
 			}
-			bod = nbod;
-			count++;
+			r = l->right;	// rcv
+			r->right = r->left;
+			r->left = l->left;
+			n->left = r;
+
+			// convert case x := foo: body
+			// to case tmp := foo: x := tmp; body.
+			// if x escapes and must be allocated
+			// on the heap, this delays the allocation
+			// until after the select has chosen this branch.
+			if(n->ninit != N && n->ninit->op == ODCL) {
+				on = nod(OXXX, N, N);
+				tempname(on, l->left->type);
+				on->sym = lookup("!tmpselect!");
+				r->left = on;
+				nbod = nod(OAS, l->left, on);
+				nbod->ninit = n->ninit;
+				n->ninit = N;
+			}
+			break;
+
+		case OSEND:
+		case ORECV:
 			break;
 		}
-	}
-	if(oc != N) {
-		bod = list(bod, nod(OBREAK, N, N));
-		oc->nbody = rev(bod);
+
+		for(n1 = listfirst(&iter1, &n->nbody); n1 != N; n1 = listnext(&iter1))
+			nbod = list(nbod, n1);
+		nbod = list(nbod, nod(OBREAK, N, N));
+		n->nbody = N;
+
+		oc = selcase(n, var);
+		if(oc != N) {
+			oc->nbody = rev(nbod);
+			res = list(res, oc);
+		}
 	}
 	setlineno(sel);