Add (temporary) error for ICT_SCOPE_GENERATE

Generate scopes were previously ignored, and this would cause a segfault
later on. This patch gives an error whenever it encounters a generate
scope. This should be removed once generate statements are implemented.

tgt-vhdl/scope.cc

@@ -625,8 +625,20 @@ static void create_skeleton_entity_for(ivl_scope_t scope)
  */
 static int draw_skeleton_scope(ivl_scope_t scope, void *_parent)
 {
-   if (ivl_scope_type(scope) == IVL_SCT_MODULE)
+   switch (ivl_scope_type(scope)) {
+   case IVL_SCT_MODULE:
       create_skeleton_entity_for(scope);
+      break;
+   case IVL_SCT_GENERATE:
+      error("No translation for generate statements yet");
+      return 1;
+   case IVL_SCT_FORK:
+      error("No translation for fork statements yet");
+      return 1;
+   default:
+      // The other scope types are expanded later on
+      break;
+   }
       
    return ivl_scope_children(scope, draw_skeleton_scope, scope);
 }

tgt-vhdl/vhdl.cc

@@ -159,10 +159,13 @@ extern "C" int target_design(ivl_design_t des)
    for (unsigned int i = 0; i < nroots; i++)
       draw_scope(roots[i], NULL);
 
-   ivl_design_process(des, draw_process, NULL);
+   // Only generate processes if there were no errors generating entities
+   // (otherwise the necessary information won't be present)
+   if (0 == g_errors)
+      ivl_design_process(des, draw_process, NULL);
 
    // Write the generated elements to the output file
-   // only if there are no errors
+   // only if there were no errors generating entities or processes
    if (0 == g_errors) {
       const char *ofname = ivl_design_flag(des, "-o");
       ofstream outfile(ofname);