gc: fix infinite recursion for embedded interfaces

Fixes #1909

R=rsc, gri
CC=golang-dev
https://golang.org/cl/5523047

Author: Luuk van Dijk

src/cmd/gc/dcl.c

@@ -940,19 +940,28 @@ interfacefield(Node *n)
 Type*
 tointerface(NodeList *l)
 {
-	Type *t, *f, **tp, *t1;
+	Type *t, *f, **tp, **otp, *t1;
 
 	t = typ(TINTER);
+	t->orig = typ(TINTER);
 
-	for(tp = &t->type; l; l=l->next) {
+	tp = &t->type;
+	otp = &t->orig->type;
+
+	for(; l; l=l->next) {
 		f = interfacefield(l->n);
+		*otp = typ(TFIELD);
+		**otp = *f;
+		otp = &(*otp)->down;
+
 		if (l->n->left == N && f->type->etype == TINTER) {
 			// embedded interface, inline methods
 			for(t1=f->type->type; t1; t1=t1->down) {
 				f = typ(TFIELD);
 				f->type = t1->type;
 				f->broke = t1->broke;
 				f->sym = t1->sym;
+				f->embedded = 1;
 				if(f->sym)
 					f->nname = newname(f->sym);
 				*tp = f;

src/cmd/gc/export.c

@@ -241,6 +241,13 @@ dumpexporttype(Type *t)
 	if(t->sym != S && t->etype != TFIELD)
 		dumppkg(t->sym->pkg);
 
+	// fmt will print the ->orig of an interface, which has the original embedded interfaces.
+	// be sure to dump them here
+	if(t->etype == TINTER)
+		for(f=t->orig->type; f; f=f->down)
+			if(f->sym == S)
+				dumpexporttype(f->type);
+
 	dumpexporttype(t->type);
 	dumpexporttype(t->down);
 
@@ -470,8 +477,8 @@ importtype(Type *pt, Type *t)
 		pt->sym->lastlineno = parserline();
 		declare(n, PEXTERN);
 		checkwidth(pt);
-	} else if(!eqtype(pt->orig, t))
-		yyerror("inconsistent definition for type %S during import\n\t%lT\n\t%lT", pt->sym, pt->orig, t);
+	} else if(!eqtype(pt->orig, t->orig))
+		yyerror("inconsistent definition for type %S during import\n\t%lT\n\t%lT", pt->sym, pt, t);
 
 	if(debug['E'])
 		print("import type %T %lT\n", pt, t);

src/cmd/gc/fmt.c

@@ -195,6 +195,7 @@ goopnames[] =
 	[OCONTINUE]	= "continue",
 	[OCOPY]		= "copy",
 	[ODEC]		= "--",
+	[ODELETE]	= "delete",
 	[ODEFER]	= "defer",
 	[ODIV]		= "/",
 	[OEQ]		= "==",
@@ -639,9 +640,15 @@ typefmt(Fmt *fp, Type *t)
 		return fmtprint(fp, "map[%T]%T", t->down, t->type);
 
 	case TINTER:
+		t = t->orig;
 		fmtstrcpy(fp, "interface {");
 		for(t1=t->type; t1!=T; t1=t1->down)
-			if(exportname(t1->sym->name)) {
+			if(!t1->sym) {
+				if(t1->down)
+					fmtprint(fp, " %T;", t1->type);
+				else
+					fmtprint(fp, " %T ", t1->type);
+			} else if(exportname(t1->sym->name)) {
 				if(t1->down)
 					fmtprint(fp, " %hS%hT;", t1->sym, t1->type);
 				else
@@ -946,6 +953,7 @@ static int opprec[] = {
 	[OCONVNOP] = 8,
 	[OCONV] = 8,
 	[OCOPY] = 8,
+	[ODELETE] = 8,
 	[OLEN] = 8,
 	[OLITERAL] = 8,
 	[OMAKESLICE] = 8,
@@ -1010,6 +1018,7 @@ static int opprec[] = {
 	[OGT] = 4,
 	[ONE] = 4,
 	[OCMPSTR] = 4,
+	[OCMPIFACE] = 4,
 
 	[OSEND] = 3,
 	[OANDAND] = 2,
@@ -1218,6 +1227,7 @@ exprfmt(Fmt *f, Node *n, int prec)
 	case OAPPEND:
 	case OCAP:
 	case OCLOSE:
+	case ODELETE:
 	case OLEN:
 	case OMAKE:
 	case ONEW:
@@ -1288,6 +1298,7 @@ exprfmt(Fmt *f, Node *n, int prec)
 		return 0;
 
 	case OCMPSTR:
+	case OCMPIFACE:
 		exprfmt(f, n->left, nprec);
 		fmtprint(f, " %#O ", n->etype);
 		exprfmt(f, n->right, nprec+1);
@@ -1303,8 +1314,10 @@ nodefmt(Fmt *f, Node *n)
 	Type *t;
 
 	t = n->type;
-	if(n->orig == N)
+	if(n->orig == N) {
+		n->orig = n;
 		fatal("node with no orig %N", n);
+	}
 
 	// we almost always want the original, except in export mode for literals
 	// this saves the importer some work, and avoids us having to redo some
@@ -1359,6 +1372,7 @@ nodedump(Fmt *fp, Node *n)
 			indent(fp);
 		}
 	}
+		fmtprint(fp, "[%p]", n);
 
 	switch(n->op) {
 	default:

src/cmd/gc/go.y

@@ -1620,7 +1620,7 @@ non_dcl_stmt:
 		$$->list = $2;
 		if($$->list == nil && curfn != N) {
 			NodeList *l;
-			
+
 			for(l=curfn->dcl; l; l=l->next) {
 				if(l->n->class == PPARAM)
 					continue;
@@ -1953,6 +1953,10 @@ hidden_interfacedcl:
 	{
 		$$ = nod(ODCLFIELD, newname($1), typenod(functype(fakethis(), $3, $5)));
 	}
+|	hidden_type
+	{
+		$$ = nod(ODCLFIELD, N, typenod($1));
+	}
 
 ohidden_funres:
 	{

src/pkg/exp/types/gcimporter.go

@@ -460,29 +460,32 @@ func (p *gcParser) parseSignature() *Func {
 	return &Func{Params: params, Results: results, IsVariadic: isVariadic}
 }
 
-// MethodSpec = ( identifier | ExportedName )  Signature .
+// MethodOrEmbedSpec = Name [ Signature ] .
 //
-func (p *gcParser) parseMethodSpec() *ast.Object {
-	if p.tok == scanner.Ident {
-		p.expect(scanner.Ident)
-	} else {
-		p.parseExportedName()
+func (p *gcParser) parseMethodOrEmbedSpec() *ast.Object {
+	p.parseName()
+	if p.tok == '(' {
+		p.parseSignature()
+		// TODO(gri) compute method object
+		return ast.NewObj(ast.Fun, "_")
 	}
-	p.parseSignature()
-
-	// TODO(gri) compute method object
-	return ast.NewObj(ast.Fun, "_")
+	// TODO lookup name and return that type
+	return ast.NewObj(ast.Typ, "_")
 }
 
-// InterfaceType = "interface" "{" [ MethodList ] "}" .
-// MethodList    = MethodSpec { ";" MethodSpec } .
+// InterfaceType = "interface" "{" [ MethodOrEmbedList ] "}" .
+// MethodOrEmbedList = MethodOrEmbedSpec { ";" MethodOrEmbedSpec } .
 //
 func (p *gcParser) parseInterfaceType() Type {
 	var methods ObjList
 
 	parseMethod := func() {
-		meth := p.parseMethodSpec()
-		methods = append(methods, meth)
+		switch m := p.parseMethodOrEmbedSpec(); m.Kind {
+		case ast.Typ:
+			// TODO expand embedded methods
+		case ast.Fun:
+			methods = append(methods, m)
+		}
 	}
 
 	p.expectKeyword("interface")

test/fixedbugs/bug395.go

@@ -0,0 +1,15 @@
+// $G $D/$F.go || echo "Bug395"
+
+// Copyright 2011 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.
+
+// Issue 1909
+// Would OOM due to exponential recursion on Foo's expanded methodset in nodefmt
+package test
+
+type Foo interface {
+       Bar() interface{Foo}
+       Baz() interface{Foo}
+       Bug() interface{Foo}
+}