Adds __str__ support to python mlir.ir.MlirModule.

* Also raises an exception on parse error.
* Removes placeholder smoketest.
* Adds docstrings.

Differential Revision: https://reviews.llvm.org/D86046

mlir/lib/Bindings/Python/MainModule.cpp

@@ -11,21 +11,14 @@
 #include <pybind11/pybind11.h>
 
 #include "IRModules.h"
-#include "mlir/IR/MLIRContext.h"
 
+namespace py = pybind11;
 using namespace mlir;
+using namespace mlir::python;
 
 PYBIND11_MODULE(_mlir, m) {
   m.doc() = "MLIR Python Native Extension";
 
-  m.def("get_test_value", []() {
-    // This is just calling a method on the MLIRContext as a smoketest
-    // for linkage.
-    MLIRContext context;
-    return std::make_tuple(std::string("From the native module"),
-                           context.isMultithreadingEnabled());
-  });
-
   // Define and populate IR submodule.
   auto irModule = m.def_submodule("ir", "MLIR IR Bindings");
   populateIRSubmodule(irModule);