eBPF backend: generate P4Runtime files if required (#4113)

* eBPF backend: generate P4Runtime files if required

* Disable generation of p4info files for filter model

It is not supported by P4RuntimeSerializer

* Add support for testing P4info files in PTF tests

* Add example P4info files

* Add P4info files for more test cases

backends/ebpf/p4c-ebpf.cpp

@@ -20,6 +20,7 @@ limitations under the License.
 #include <string>
 
 #include "backends/ebpf/version.h"
+#include "control-plane/p4RuntimeSerializer.h"
 #include "ebpfBackend.h"
 #include "ebpfOptions.h"
 #include "frontends/common/applyOptionsPragmas.h"
@@ -71,6 +72,12 @@ void compile(EbpfOptions &options) {
         program = frontend.run(options, program);
         if (::errorCount() > 0) return;
     }
+
+    if (!options.arch.isNullOrEmpty() && options.arch != "filter") {
+        P4::serializeP4RuntimeIfRequired(program, options);
+        if (::errorCount() > 0) return;
+    }
+
     EBPF::MidEnd midend;
     midend.addDebugHook(hook);
     auto toplevel = midend.run(options, program);