#900 pmpi- unify argument handling of --vt_trace_mpi

- Now uses an option instead of a flag. Specify the form of MPI to enable.
  In C++, the options should be separated with spaces:

      --vt_mpi_trace internal
      --vt_mpi_trace external
      --vt_mpi_trace internal externall

  'internal' is the few select internal calls, 'external' is PMPI overall.

src/vt/configs/arguments/args.cc

@@ -185,6 +185,11 @@ namespace vt { namespace arguments {
 
 /*static*/ bool        ArgParse::parsed_                = false;
 
+// Temporary variables used only for parsing artifacts.
+namespace {
+  std::vector<std::string> arg_trace_mpi;
+}
+
 void addColorArgs(CLI::App& app) {
   auto quiet  = "Quiet the output from vt (only errors, warnings)";
   auto always = "Colorize output (default)";
@@ -277,9 +282,7 @@ void addTraceArgs(CLI::App& app) {
    * Flags to control tracing output
    */
   auto trace     = "Enable tracing (must be compiled with trace_enabled)";
-  auto trace_mpi = "Enable tracing of select internal MPI calls"
-    " (must be compiled with trace_enabled)";
-  auto trace_pmpi = "Enable tracing of external PMPI calls"
+  auto trace_mpi = "Enable tracing of MPI calls"
     " (must be compiled with trace_enabled)";
   auto tfile     = "Name of trace files";
   auto tdir      = "Name of directory for trace files";
@@ -296,8 +299,8 @@ void addTraceArgs(CLI::App& app) {
   auto tpolled   = "Trace AsyncEvent component polling (inc. MPI_Isend requests)";
   auto tirecv     = "Trace MPI_Irecv request polling";
   auto n  = app.add_flag("--vt_trace",              ArgConfig::vt_trace,           trace);
-  auto nm = app.add_flag("--vt_trace_mpi",          ArgConfig::vt_trace_mpi,       trace_mpi);
-  auto no = app.add_flag("--vt_trace_pmpi",         ArgConfig::vt_trace_pmpi,      trace_pmpi);
+  auto nm = app.add_option("--vt_trace_mpi",        arg_trace_mpi,                 trace_mpi)
+    ->check(CLI::IsMember({"internal", "external"}));
   auto o  = app.add_option("--vt_trace_file",       ArgConfig::vt_trace_file,      tfile, "");
   auto p  = app.add_option("--vt_trace_dir",        ArgConfig::vt_trace_dir,       tdir,  "");
   auto q  = app.add_option("--vt_trace_mod",        ArgConfig::vt_trace_mod,       tmod,  1);
@@ -316,7 +319,6 @@ void addTraceArgs(CLI::App& app) {
   auto traceGroup = "Tracing Configuration";
   n->group(traceGroup);
   nm->group(traceGroup);
-  no->group(traceGroup);
   o->group(traceGroup);
   p->group(traceGroup);
   q->group(traceGroup);
@@ -657,6 +659,19 @@ std::tuple<int, std::string> parseArguments(CLI::App& app, int& argc, char**& ar
   return result;
 }
 
+/**
+ * \internal
+ * Application specific cleanup and mapping to actual app args.
+ */
+void postParseTransform() {
+  auto contains = [](std::vector<std::string> &v, std::string str){
+    return std::find(v.begin(), v.end(), str) not_eq v.end();
+  };
+
+  ArgConfig::vt_trace_mpi = contains(arg_trace_mpi, "internal");
+  ArgConfig::vt_trace_pmpi = contains(arg_trace_mpi, "external");
+}
+
 std::tuple<int, std::string> parseArguments(CLI::App& app, int& argc, char**& argv) {
 
   std::vector<char*> vt_args;
@@ -732,6 +747,8 @@ std::tuple<int, std::string> parseArguments(CLI::App& app, int& argc, char**& ar
   ArgConfig::mpi_init_args = mpi_args;
   ArgConfig::passthru_args = passthru_args;
 
+  postParseTransform();
+
   // Rebuild passthru into ref-returned argc/argv
   // (only pass-through, not MPI_Init-bound)
 

src/vt/pmpi/pmpi_component.h

@@ -66,8 +66,7 @@ struct PMPIComponent : runtime::component::Component<PMPIComponent> {
 
   using ArgType = vt::arguments::ArgConfig;
 
-  PMPIComponent() {
-  }
+  PMPIComponent() = default;
 
   std::string name() override { return "PMPI"; }
 

src/vt/runtime/runtime_banner.cc

@@ -209,6 +209,12 @@ void Runtime::printStartupBanner() {
       green, reset, magenta, opt, reset, compile, reset
     );
   };
+  auto opt_on_value = [=](std::string opt, std::string val, std::string compile) -> std::string {
+    return fmt::format(
+      "{}Option:{} flag {}{}{} on with value \"{}\": {}{}\n",
+      green, reset, magenta, opt, reset, val, compile, reset
+    );
+  };
   auto opt_off = [=](std::string opt, std::string compile) -> std::string {
     return fmt::format(
       "{}Option:{} flag {}{}{} not set: {}{}\n",
@@ -455,12 +461,12 @@ void Runtime::printStartupBanner() {
     }
     if (ArgType::vt_trace_mpi) {
       auto f11 = fmt::format("Tracing MPI invocations (select internal calls)");
-      auto f12 = opt_on("--vt_trace_mpi", f11);
+      auto f12 = opt_on_value("--vt_trace_mpi", "internal", f11);
       fmt::print("{}\t{}{}", vt_pre, f12, reset);
     }
     if (ArgType::vt_trace_pmpi) {
-      auto f11 = fmt::format("Tracing PMPI invocations (external calls)");
-      auto f12 = opt_on("--vt_trace_mpi", f11);
+      auto f11 = fmt::format("Tracing MPI invocations (external calls)");
+      auto f12 = opt_on_value("--vt_trace_mpi", "external", f11);
       fmt::print("{}\t{}{}", vt_pre, f12, reset);
     }
     if (ArgType::vt_trace_event_polling) {