[python] Add `walk_with_filter` to walk subset of IR (#7591)

This adds `walk_with_filter` python method to invoke callbacks
only for subset of operations. We require GIL to call python function
so this could improve performance of the tools based on Python API.

```
Starting walk_with_filter
walk_with_filter elapsed time: 0.005462 seconds cnt=1
Starting operation.walk
operation.walk elapsed time: 1.061360 seconds cnt=2
```

integration_test/Bindings/Python/support/walk.py

@@ -0,0 +1,76 @@
+# REQUIRES: bindings_python
+# RUN: %PYTHON% %s | FileCheck %s
+
+import circt
+from circt.support import walk_with_filter
+from circt.dialects import hw
+from circt.ir import Context, Module, WalkOrder, WalkResult
+
+
+def test_walk_with_filter():
+  ctx = Context()
+  circt.register_dialects(ctx)
+  module = Module.parse(
+      r"""
+    builtin.module {
+      hw.module @f() {
+        hw.output
+      }
+    }
+  """,
+      ctx,
+  )
+
+  def callback(op):
+    print(op.name)
+    return WalkResult.ADVANCE
+
+  # Test post-order walk.
+  # CHECK:       Post-order
+  # CHECK-NEXT:  hw.output
+  # CHECK-NEXT:  hw.module
+  # CHECK-NOT:  builtin.module
+  print("Post-order")
+  walk_with_filter(module.operation, [hw.HWModuleOp, hw.OutputOp], callback,
+                   WalkOrder.POST_ORDER)
+
+  # Test pre-order walk.
+  # CHECK-NEXT:  Pre-order
+  # CHECK-NOT:  builtin.module
+  # CHECK-NEXT:  hw.module
+  # CHECK-NEXT:  hw.output
+  print("Pre-order")
+  walk_with_filter(module.operation, [hw.HWModuleOp, hw.OutputOp], callback,
+                   WalkOrder.PRE_ORDER)
+
+  # Test interrupt.
+  # CHECK-NEXT:  Interrupt post-order
+  # CHECK-NEXT:  hw.output
+  print("Interrupt post-order")
+
+  def interrupt_callback(op):
+    print(op.name)
+    return WalkResult.INTERRUPT
+
+  walk_with_filter(module.operation, [hw.OutputOp], interrupt_callback,
+                   WalkOrder.POST_ORDER)
+
+  # Test exception.
+  # CHECK: Exception
+  # CHECK-NEXT: hw.output
+  # CHECK-NEXT: Exception raised
+  print("Exception")
+
+  def exception_callback(op):
+    print(op.name)
+    raise ValueError
+    return WalkResult.ADVANCE
+
+  try:
+    walk_with_filter(module.operation, [hw.OutputOp], exception_callback,
+                     WalkOrder.POST_ORDER)
+  except RuntimeError:
+    print("Exception raised")
+
+
+test_walk_with_filter()

lib/Bindings/Python/CIRCTModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 
 #include "circt-c/Conversion.h"
 #include "circt-c/Dialect/Comb.h"
@@ -142,4 +142,6 @@ PYBIND11_MODULE(_circt, m) {
   circt::python::populateDialectOMSubmodule(om);
   py::module sv = m.def_submodule("_sv", "SV API");
   circt::python::populateDialectSVSubmodule(sv);
+  py::module support = m.def_submodule("_support", "CIRCT support");
+  circt::python::populateSupportSubmodule(support);
 }

lib/Bindings/Python/CIRCTModules.h

@@ -1,4 +1,4 @@
-//===- DialectModules.h - Populate submodules -----------------------------===//
+//===- CIRCTModules.h - Populate submodules -------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,12 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// Functions to populate each dialect's submodule (if provided).
+// Functions to populate submodules in CIRCT (if provided).
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef CIRCT_BINDINGS_PYTHON_DIALECTMODULES_H
-#define CIRCT_BINDINGS_PYTHON_DIALECTMODULES_H
+#ifndef CIRCT_BINDINGS_PYTHON_CIRCTMODULES_H
+#define CIRCT_BINDINGS_PYTHON_CIRCTMODULES_H
 
 #include <pybind11/pybind11.h>
 
@@ -24,6 +24,7 @@ void populateDialectMSFTSubmodule(pybind11::module &m);
 void populateDialectOMSubmodule(pybind11::module &m);
 void populateDialectSeqSubmodule(pybind11::module &m);
 void populateDialectSVSubmodule(pybind11::module &m);
+void populateSupportSubmodule(pybind11::module &m);
 
 } // namespace python
 } // namespace circt

lib/Bindings/Python/CMakeLists.txt

@@ -20,6 +20,7 @@ declare_mlir_python_extension(CIRCTBindingsPythonExtension
     OMModule.cpp
     MSFTModule.cpp
     SeqModule.cpp
+    SupportModule.cpp
     SVModule.cpp
   EMBED_CAPI_LINK_LIBS
     CIRCTCAPIComb

lib/Bindings/Python/ESIModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 
 #include "circt/Dialect/ESI/ESIDialect.h"
 

lib/Bindings/Python/HWModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 
 #include "circt-c/Dialect/HW.h"
 

lib/Bindings/Python/MSFTModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 
 #include "circt-c/Dialect/MSFT.h"
 #include "circt/Dialect/MSFT/MSFTDialect.h"

lib/Bindings/Python/OMModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 #include "circt-c/Dialect/HW.h"
 #include "circt-c/Dialect/OM.h"
 #include "mlir-c/BuiltinAttributes.h"

lib/Bindings/Python/SVModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 
 #include "circt-c/Dialect/SV.h"
 #include "mlir-c/Bindings/Python/Interop.h"

lib/Bindings/Python/SeqModule.cpp

@@ -6,7 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "DialectModules.h"
+#include "CIRCTModules.h"
 
 #include "circt-c/Dialect/Seq.h"
 #include "mlir/Bindings/Python/PybindAdaptors.h"

lib/Bindings/Python/SupportModule.cpp

@@ -0,0 +1,86 @@
+//===- SupportModule.cpp - Support API pybind module ----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "CIRCTModules.h"
+
+#include "mlir/Bindings/Python/PybindAdaptors.h"
+
+#include "PybindUtils.h"
+#include "mlir-c/Support.h"
+#include <pybind11/pybind11.h>
+#include <pybind11/pytypes.h>
+#include <pybind11/stl.h>
+
+namespace py = pybind11;
+
+using namespace circt;
+using namespace mlir::python::adaptors;
+
+/// Populate the support python module.
+void circt::python::populateSupportSubmodule(py::module &m) {
+  m.doc() = "CIRCT Python utils";
+  // Walk with filter.
+  m.def(
+      "_walk_with_filter",
+      [](MlirOperation operation, std::vector<std::string> op_names,
+         std::function<MlirWalkResult(MlirOperation)> callback,
+         MlirWalkOrder walkOrder) {
+        struct UserData {
+          std::function<MlirWalkResult(MlirOperation)> callback;
+          bool gotException;
+          std::string exceptionWhat;
+          py::object exceptionType;
+          std::vector<MlirIdentifier> op_names;
+        };
+
+        std::vector<MlirIdentifier> op_names_identifiers;
+
+        // Construct MlirIdentifier from string to perform pointer comparison.
+        for (auto &op_name : op_names)
+          op_names_identifiers.push_back(mlirIdentifierGet(
+              mlirOperationGetContext(operation),
+              mlirStringRefCreateFromCString(op_name.c_str())));
+
+        UserData userData{callback, false, {}, {}, op_names_identifiers};
+        MlirOperationWalkCallback walkCallback = [](MlirOperation op,
+                                                    void *userData) {
+          UserData *calleeUserData = static_cast<UserData *>(userData);
+          auto op_name = mlirOperationGetName(op);
+
+          // Check if the operation name is in the filter.
+          bool inFilter = false;
+          for (auto &op_name_identifier : calleeUserData->op_names) {
+            if (mlirIdentifierEqual(op_name, op_name_identifier)) {
+              inFilter = true;
+              break;
+            }
+          }
+
+          // If the operation name is not in the filter, skip it.
+          if (!inFilter)
+            return MlirWalkResult::MlirWalkResultAdvance;
+
+          try {
+            return (calleeUserData->callback)(op);
+          } catch (py::error_already_set &e) {
+            calleeUserData->gotException = true;
+            calleeUserData->exceptionWhat = e.what();
+            calleeUserData->exceptionType = e.type();
+            return MlirWalkResult::MlirWalkResultInterrupt;
+          }
+        };
+        mlirOperationWalk(operation, walkCallback, &userData, walkOrder);
+        if (userData.gotException) {
+          std::string message("Exception raised in callback: ");
+          message.append(userData.exceptionWhat);
+          throw std::runtime_error(message);
+        }
+      },
+      py::arg("op"), py::arg("op_names"), py::arg("callback"),
+      py::arg("walk_order"));
+}

lib/Bindings/Python/support.py

@@ -4,6 +4,8 @@
 
 from . import ir
 
+from ._mlir_libs._circt._support import _walk_with_filter
+from .ir import Operation
 from contextlib import AbstractContextManager
 from contextvars import ContextVar
 from typing import List
@@ -409,3 +411,13 @@ class NamedValueOpView:
   def operation(self):
     """Get the operation associated with this builder."""
     return self.opview.operation
+
+
+# Helper function to walk operation with a filter on operation names.
+# `op_views` is a list of operation views to visit. This is a wrapper
+# around the C++ implementation of walk_with_filter.
+def walk_with_filter(operation: Operation, op_views: List[ir.OpView], callback,
+                     walk_order):
+  op_names_identifiers = [name.OPERATION_NAME for name in op_views]
+  return _walk_with_filter(operation, op_names_identifiers, callback,
+                           walk_order)