Fix for issue #208

backends/bmv2/jsonconverter.cpp

@@ -1995,6 +1995,11 @@ void JsonConverter::addTypesAndInstances(const IR::Type_StructLike* type, bool m
     for (auto f : *type->fields) {
         auto ft = typeMap->getType(f, true);
         if (ft->is<IR::Type_StructLike>()) {
+            // The headers struct can not contain nested structures.
+            if (!meta && !ft->is<IR::Type_Header>()) {
+                ::error("Type %1% should only contain headers or header stacks", type);
+                return;
+            }
             auto st = ft->to<IR::Type_StructLike>();
             createJsonType(st);
         }
@@ -2013,10 +2018,6 @@ void JsonConverter::addTypesAndInstances(const IR::Type_StructLike* type, bool m
             // Done elsewhere
             continue;
         } else {
-            if (!meta) {
-                ::error("Type %1% should only contain headers or stacks", type);
-                return;
-            }
             // Treat this field like a scalar local variable
             auto scalarFields = scalarsStruct->get("fields")->to<Util::JsonArray>();
             CHECK_NULL(scalarFields);

testdata/p4_16_bmv_errors/README.md

@@ -1 +1,2 @@
 This folder contains negative tests: which are supposed to generate compiler errors when compiled.
+All files should be named like *-bmv2.p4

testdata/p4_16_bmv_errors/nested-headers-bmv2.p4

@@ -0,0 +1,54 @@
+/*
+Copyright 2016 VMware, Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include <core.p4>
+#include <v1model.p4>
+
+header foo {
+  bit<8> foo_1;
+  bit<7> foo_2;
+  bit<8> foo_3;
+}
+
+header bar {
+  bit<2> bar_1;
+}
+
+struct baz {
+  foo baz_1;
+}
+
+struct Headers {
+    bar a;
+    baz b;
+}
+
+struct Meta {}
+
+parser p(packet_in b, out Headers h, inout Meta m, inout standard_metadata_t sm) {
+    state start {
+        transition accept;
+    }
+}
+
+control vrfy(in Headers h, inout Meta m) { apply {} }
+control update(inout Headers h, inout Meta m) { apply {} }
+
+control egress(inout Headers h, inout Meta m, inout standard_metadata_t sm) { apply {} }
+control ingress(inout Headers h, inout Meta m, inout standard_metadata_t sm) { apply {} }
+control deparser(packet_out b, in Headers h) { apply {} }
+
+V1Switch(p(), vrfy(), ingress(), egress(), update(), deparser()) main;