Add Python binding to run a PassManager on a MLIR Module

mlir/lib/Bindings/Python/Pass.cpp

py::class_<PyPassManager>(m, "PassManager")
                                    pipeline + "'.");
             return new PyPassManager(passManager);
           },
           py::arg("pipeline"), py::arg("context") = py::none(),
           "Parse a textual pass-pipeline and return a top-level PassManager "
           "that can be applied on a Module. Throw a ValueError if the pipeline "
           "can't be parsed")
       .def(
+          "run",
+          [](PyPassManager &passManager, PyModule &module) {
+            MlirLogicalResult status =
+                mlirPassManagerRun(passManager.get(), module.get());
+            if (mlirLogicalResultIsFailure(status))
+              throw SetPyError(PyExc_RuntimeError,
+                               "Failure while executing pass pipeline.");
+          },
+          "Run the pass manager on the provided module, throw a RuntimeError "
+          "on failure.")
+      .def(
           "__str__",
           [](PyPassManager &self) {
             MlirPassManager passManager = self.get();
             PyPrintAccumulator printAccum;
             mlirPrintPassPipeline(
                 mlirPassManagerGetAsOpPassManager(passManager),
                 printAccum.getCallback(), printAccum.getUserData());
             return printAccum.join();
           },
           "Print the textual representation for this PassManager, suitable to "
           "be passed to `parse` for round-tripping.");
 }

mlir/test/Bindings/Python/pass_manager.py

 # RUN: %PYTHON %s 2>&1 | FileCheck %s
 
 import gc, sys
 from mlir.ir import *
 from mlir.passmanager import *
 
 # Log everything to stderr and flush so that we have a unified stream to match
-# errors emitted by MLIR to stderr. TODO: this shouldn't be needed when
-# everything is plumbed.
+# errors/info emitted by MLIR to stderr.
 def log(*args):
   print(*args, file=sys.stderr)
   sys.stderr.flush()
 
 def run(f):
   log("\nTEST:", f.__name__)
   f()
   gc.collect()
with Context():
     try:
       pm = PassManager.parse("unknown-pass")
     except ValueError as e:
       # CHECK: ValueError exception: invalid pass pipeline 'unknown-pass'.
       log("ValueError exception:", e)
     else:
       log("Exception not produced")
 run(testParseFail)
+
+
+# Verify that a pass manager can execute on IR
+# CHECK-LABEL: TEST: testRun
+def testRunPipeline():
+  with Context():
+    pm = PassManager.parse("print-op-stats")
+    module = Module.parse(r"""func @successfulParse() { return }""")
+    pm.run(module)
+# CHECK: Operations encountered:
+# CHECK: func              , 1
+# CHECK: module            , 1
+# CHECK: module_terminator , 1
+# CHECK: std.return        , 1
+run(testRunPipeline)