add creator for missing types, to avoid crashes when

signature is absent from object file.

R=rsc
DELTA=18  (18 added, 0 deleted, 0 changed)
OCL=18315
CL=18323

src/lib/reflect/test.go

@@ -91,6 +91,7 @@ func main() {
 	var s string;
 	var t reflect.Type;
 
+	typedump("missing", "$missing$");
 	typedump("int", "int");
 	typedump("int8", "int8");
 	typedump("int16", "int16");
@@ -106,6 +107,7 @@ func main() {
 	typedump("float64", "float64");
 	typedump("float80", "float80");
 	typedump("int8", "int8");
+	typedump("whoknows.whatsthis", "$missing$");
 	typedump("**int8", "**int8");
 	typedump("**P.integer", "**P.integer");
 	typedump("[32]int32", "[32]int32");

src/lib/reflect/value.go

@@ -60,6 +60,21 @@ func AddrToPtrFloat80(Addr) *float80
 func AddrToPtrString(Addr) *string
 func AddrToPtrBool(Addr) *bool
 
+// -- Missing
+
+export type MissingValue interface {
+	Kind()	int;
+	Type()	Type;
+}
+
+type MissingValueStruct struct {
+	CommonV
+}
+
+func MissingCreator(typ Type, addr Addr) Value {
+	return &MissingValueStruct{ CommonV{IntKind, typ, addr} }
+}
+
 // -- Int
 
 export type IntValue interface {
@@ -676,6 +691,7 @@ var creator *map[int] Creator
 
 func init() {
 	creator = new(map[int] Creator);
+	creator[MissingKind] = &MissingCreator;
 	creator[IntKind] = &IntCreator;
 	creator[Int8Kind] = &Int8Creator;
 	creator[Int16Kind] = &Int16Creator;