[Mlir-commits] [mlir] afe75b4 - [mlir python] Add nanobind support for standalone dialects. (#117922)

llvmlistbot at llvm.org llvmlistbot at llvm.org
Tue Dec 3 09:13:38 PST 2024


Author: Peter Hawkins
Date: 2024-12-03T09:13:34-08:00
New Revision: afe75b4d5fcebd6fdd292ca1797de1b35cb687b0

URL: https://github.com/llvm/llvm-project/commit/afe75b4d5fcebd6fdd292ca1797de1b35cb687b0
DIFF: https://github.com/llvm/llvm-project/commit/afe75b4d5fcebd6fdd292ca1797de1b35cb687b0.diff

LOG: [mlir python] Add nanobind support for standalone dialects. (#117922)

This PR allows out-of-tree dialects to write Python dialect modules
using nanobind instead of pybind11.

It may make sense to migrate in-tree dialects and some of the ODS Python
infrastructure to nanobind, but that is a topic for a future change.

This PR makes the following changes:
* adds nanobind to the CMake and Bazel build systems. We also add
robin_map to the Bazel build, which is a dependency of nanobind.
* adds a PYTHON_BINDING_LIBRARY option to various CMake functions, such
as declare_mlir_python_extension, allowing users to select a Python
binding library.
* creates a fork of mlir/include/mlir/Bindings/Python/PybindAdaptors.h
named NanobindAdaptors.h. This plays the same role, using nanobind
instead of pybind11.
* splits CollectDiagnosticsToStringScope out of PybindAdaptors.h and
into a new header mlir/include/mlir/Bindings/Python/Diagnostics.h, since
it is code that is no way related to pybind11 or for that matter,
Python.
* changed the standalone Python extension example to have both pybind11
and nanobind variants.
* changed mlir/python/mlir/dialects/python_test.py to have both pybind11
and nanobind variants.

Notes:
* A slightly unfortunate thing that I needed to do in the CMake
integration was to use FindPython in addition to FindPython3, since
nanobind's CMake integration expects the Python_ names for variables.
Perhaps there's a better way to do this.

Added: 
    mlir/examples/standalone/python/StandaloneExtensionNanobind.cpp
    mlir/examples/standalone/python/StandaloneExtensionPybind11.cpp
    mlir/examples/standalone/python/mlir_standalone/dialects/standalone_nanobind.py
    mlir/examples/standalone/python/mlir_standalone/dialects/standalone_pybind11.py
    mlir/include/mlir/Bindings/Python/Diagnostics.h
    mlir/include/mlir/Bindings/Python/NanobindAdaptors.h
    mlir/test/python/lib/PythonTestModuleNanobind.cpp
    mlir/test/python/lib/PythonTestModulePybind11.cpp
    utils/bazel/third_party_build/nanobind.BUILD
    utils/bazel/third_party_build/robin_map.BUILD

Modified: 
    mlir/cmake/modules/AddMLIRPython.cmake
    mlir/cmake/modules/MLIRDetectPythonEnv.cmake
    mlir/docs/Bindings/Python.md
    mlir/examples/standalone/python/CMakeLists.txt
    mlir/examples/standalone/test/python/smoketest.py
    mlir/include/mlir/Bindings/Python/PybindAdaptors.h
    mlir/lib/Bindings/Python/DialectLLVM.cpp
    mlir/lib/Bindings/Python/TransformInterpreter.cpp
    mlir/python/CMakeLists.txt
    mlir/python/mlir/dialects/python_test.py
    mlir/python/requirements.txt
    mlir/test/python/dialects/python_test.py
    mlir/test/python/lib/CMakeLists.txt
    utils/bazel/WORKSPACE
    utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

Removed: 
    mlir/examples/standalone/python/StandaloneExtension.cpp
    mlir/examples/standalone/python/mlir_standalone/dialects/standalone.py
    mlir/test/python/lib/PythonTestModule.cpp


################################################################################
diff  --git a/mlir/cmake/modules/AddMLIRPython.cmake b/mlir/cmake/modules/AddMLIRPython.cmake
index 7b91f43e2d57fd..67619a90c90be9 100644
--- a/mlir/cmake/modules/AddMLIRPython.cmake
+++ b/mlir/cmake/modules/AddMLIRPython.cmake
@@ -114,10 +114,11 @@ endfunction()
 #   EMBED_CAPI_LINK_LIBS: Dependent CAPI libraries that this extension depends
 #     on. These will be collected for all extensions and put into an
 #     aggregate dylib that is linked against.
+#   PYTHON_BINDINGS_LIBRARY: Either pybind11 or nanobind.
 function(declare_mlir_python_extension name)
   cmake_parse_arguments(ARG
     ""
-    "ROOT_DIR;MODULE_NAME;ADD_TO_PARENT"
+    "ROOT_DIR;MODULE_NAME;ADD_TO_PARENT;PYTHON_BINDINGS_LIBRARY"
     "SOURCES;PRIVATE_LINK_LIBS;EMBED_CAPI_LINK_LIBS"
     ${ARGN})
 
@@ -126,15 +127,20 @@ function(declare_mlir_python_extension name)
   endif()
   set(_install_destination "src/python/${name}")
 
+  if(NOT ARG_PYTHON_BINDINGS_LIBRARY)
+    set(ARG_PYTHON_BINDINGS_LIBRARY "pybind11")
+  endif()
+
   add_library(${name} INTERFACE)
   set_target_properties(${name} PROPERTIES
     # Yes: Leading-lowercase property names are load bearing and the recommended
     # way to do this: https://gitlab.kitware.com/cmake/cmake/-/issues/19261
-    EXPORT_PROPERTIES "mlir_python_SOURCES_TYPE;mlir_python_EXTENSION_MODULE_NAME;mlir_python_EMBED_CAPI_LINK_LIBS;mlir_python_DEPENDS"
+    EXPORT_PROPERTIES "mlir_python_SOURCES_TYPE;mlir_python_EXTENSION_MODULE_NAME;mlir_python_EMBED_CAPI_LINK_LIBS;mlir_python_DEPENDS;mlir_python_BINDINGS_LIBRARY"
     mlir_python_SOURCES_TYPE extension
     mlir_python_EXTENSION_MODULE_NAME "${ARG_MODULE_NAME}"
     mlir_python_EMBED_CAPI_LINK_LIBS "${ARG_EMBED_CAPI_LINK_LIBS}"
     mlir_python_DEPENDS ""
+    mlir_python_BINDINGS_LIBRARY "${ARG_PYTHON_BINDINGS_LIBRARY}"
   )
 
   # Set the interface source and link_libs properties of the target
@@ -223,12 +229,14 @@ function(add_mlir_python_modules name)
     elseif(_source_type STREQUAL "extension")
       # Native CPP extension.
       get_target_property(_module_name ${sources_target} mlir_python_EXTENSION_MODULE_NAME)
+      get_target_property(_bindings_library ${sources_target} mlir_python_BINDINGS_LIBRARY)
       # Transform relative source to based on root dir.
       set(_extension_target "${modules_target}.extension.${_module_name}.dso")
       add_mlir_python_extension(${_extension_target} "${_module_name}"
         INSTALL_COMPONENT ${modules_target}
         INSTALL_DIR "${ARG_INSTALL_PREFIX}/_mlir_libs"
         OUTPUT_DIRECTORY "${ARG_ROOT_PREFIX}/_mlir_libs"
+        PYTHON_BINDINGS_LIBRARY ${_bindings_library}
         LINK_LIBS PRIVATE
           ${sources_target}
           ${ARG_COMMON_CAPI_LINK_LIBS}
@@ -634,7 +642,7 @@ endfunction()
 function(add_mlir_python_extension libname extname)
   cmake_parse_arguments(ARG
   ""
-  "INSTALL_COMPONENT;INSTALL_DIR;OUTPUT_DIRECTORY"
+  "INSTALL_COMPONENT;INSTALL_DIR;OUTPUT_DIRECTORY;PYTHON_BINDINGS_LIBRARY"
   "SOURCES;LINK_LIBS"
   ${ARGN})
   if(ARG_UNPARSED_ARGUMENTS)
@@ -644,9 +652,16 @@ function(add_mlir_python_extension libname extname)
   # The actual extension library produces a shared-object or DLL and has
   # sources that must be compiled in accordance with pybind11 needs (RTTI and
   # exceptions).
-  pybind11_add_module(${libname}
-    ${ARG_SOURCES}
-  )
+  if(NOT DEFINED ARG_PYTHON_BINDINGS_LIBRARY OR ARG_PYTHON_BINDINGS_LIBRARY STREQUAL "pybind11")
+    pybind11_add_module(${libname}
+      ${ARG_SOURCES}
+    )
+  elseif(ARG_PYTHON_BINDINGS_LIBRARY STREQUAL "nanobind")
+    nanobind_add_module(${libname}
+      NB_DOMAIN mlir
+      ${ARG_SOURCES}
+    )
+  endif()
 
   # The extension itself must be compiled with RTTI and exceptions enabled.
   # Also, some warning classes triggered by pybind11 are disabled.

diff  --git a/mlir/cmake/modules/MLIRDetectPythonEnv.cmake b/mlir/cmake/modules/MLIRDetectPythonEnv.cmake
index 05397b7a1e1c75..c62ac7fa615ea6 100644
--- a/mlir/cmake/modules/MLIRDetectPythonEnv.cmake
+++ b/mlir/cmake/modules/MLIRDetectPythonEnv.cmake
@@ -21,6 +21,12 @@ macro(mlir_configure_python_dev_packages)
 
     find_package(Python3 ${LLVM_MINIMUM_PYTHON_VERSION}
       COMPONENTS Interpreter ${_python_development_component} REQUIRED)
+
+    # It's a little silly to detect Python a second time, but nanobind's cmake
+    # code looks for Python_ not Python3_.
+    find_package(Python ${LLVM_MINIMUM_PYTHON_VERSION}
+      COMPONENTS Interpreter ${_python_development_component} REQUIRED)
+
     unset(_python_development_component)
     message(STATUS "Found python include dirs: ${Python3_INCLUDE_DIRS}")
     message(STATUS "Found python libraries: ${Python3_LIBRARIES}")
@@ -31,6 +37,13 @@ macro(mlir_configure_python_dev_packages)
     message(STATUS "Python prefix = '${PYTHON_MODULE_PREFIX}', "
                   "suffix = '${PYTHON_MODULE_SUFFIX}', "
                   "extension = '${PYTHON_MODULE_EXTENSION}")
+
+    mlir_detect_nanobind_install()
+    find_package(nanobind 2.2 CONFIG REQUIRED)
+    message(STATUS "Found nanobind v${nanobind_VERSION}: ${nanobind_INCLUDE_DIR}")
+    message(STATUS "Python prefix = '${PYTHON_MODULE_PREFIX}', "
+                  "suffix = '${PYTHON_MODULE_SUFFIX}', "
+                  "extension = '${PYTHON_MODULE_EXTENSION}")
   endif()
 endmacro()
 
@@ -58,3 +71,29 @@ function(mlir_detect_pybind11_install)
     set(pybind11_DIR "${PACKAGE_DIR}" PARENT_SCOPE)
   endif()
 endfunction()
+
+
+# Detects a nanobind package installed in the current python environment
+# and sets variables to allow it to be found. This allows nanobind to be
+# installed via pip, which typically yields a much more recent version than
+# the OS install, which will be available otherwise.
+function(mlir_detect_nanobind_install)
+  if(nanobind_DIR)
+    message(STATUS "Using explicit nanobind cmake directory: ${nanobind_DIR} (-Dnanobind_DIR to change)")
+  else()
+    message(STATUS "Checking for nanobind in python path...")
+    execute_process(
+      COMMAND "${Python3_EXECUTABLE}"
+      -c "import nanobind;print(nanobind.cmake_dir(), end='')"
+      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+      RESULT_VARIABLE STATUS
+      OUTPUT_VARIABLE PACKAGE_DIR
+      ERROR_QUIET)
+    if(NOT STATUS EQUAL "0")
+      message(STATUS "not found (install via 'pip install nanobind' or set nanobind_DIR)")
+      return()
+    endif()
+    message(STATUS "found (${PACKAGE_DIR})")
+    set(nanobind_DIR "${PACKAGE_DIR}" PARENT_SCOPE)
+  endif()
+endfunction()

diff  --git a/mlir/docs/Bindings/Python.md b/mlir/docs/Bindings/Python.md
index 6e52c4deaad9aa..a0bd1cac118bad 100644
--- a/mlir/docs/Bindings/Python.md
+++ b/mlir/docs/Bindings/Python.md
@@ -1138,12 +1138,14 @@ attributes and types must connect to the relevant C APIs for building and
 inspection, which must be provided first. Bindings for `Attribute` and `Type`
 subclasses can be defined using
 [`include/mlir/Bindings/Python/PybindAdaptors.h`](https://github.com/llvm/llvm-project/blob/main/mlir/include/mlir/Bindings/Python/PybindAdaptors.h)
-utilities that mimic pybind11 API for defining functions and properties. These
-bindings are to be included in a separate pybind11 module. The utilities also
-provide automatic casting between C API handles `MlirAttribute` and `MlirType`
-and their Python counterparts so that the C API handles can be used directly in
-binding implementations. The methods and properties provided by the bindings
-should follow the principles discussed above.
+or
+[`include/mlir/Bindings/Python/NanobindAdaptors.h`](https://github.com/llvm/llvm-project/blob/main/mlir/include/mlir/Bindings/Python/NanobindAdaptors.h)
+utilities that mimic pybind11/nanobind API for defining functions and
+properties. These bindings are to be included in a separate module. The
+utilities also provide automatic casting between C API handles `MlirAttribute`
+and `MlirType` and their Python counterparts so that the C API handles can be
+used directly in binding implementations. The methods and properties provided by
+the bindings should follow the principles discussed above.
 
 The attribute and type bindings for a dialect can be located in
 `lib/Bindings/Python/Dialect<Name>.cpp` and should be compiled into a separate
@@ -1179,7 +1181,9 @@ make the passes available along with the dialect.
 Dialect functionality other than IR objects or passes, such as helper functions,
 can be exposed to Python similarly to attributes and types. C API is expected to
 exist for this functionality, which can then be wrapped using pybind11 and
-`[include/mlir/Bindings/Python/PybindAdaptors.h](https://github.com/llvm/llvm-project/blob/main/mlir/include/mlir/Bindings/Python/PybindAdaptors.h)`
+`[include/mlir/Bindings/Python/PybindAdaptors.h](https://github.com/llvm/llvm-project/blob/main/mlir/include/mlir/Bindings/Python/PybindAdaptors.h)`,
+or nanobind and
+`[include/mlir/Bindings/Python/NanobindAdaptors.h](https://github.com/llvm/llvm-project/blob/main/mlir/include/mlir/Bindings/Python/NanobindAdaptors.h)`
 utilities to connect to the rest of Python API. The bindings can be located in a
-separate pybind11 module or in the same module as attributes and types, and
+separate module or in the same module as attributes and types, and
 loaded along with the dialect.

diff  --git a/mlir/examples/standalone/python/CMakeLists.txt b/mlir/examples/standalone/python/CMakeLists.txt
index a8c43827a5a375..69c82fd9135798 100644
--- a/mlir/examples/standalone/python/CMakeLists.txt
+++ b/mlir/examples/standalone/python/CMakeLists.txt
@@ -17,18 +17,32 @@ declare_mlir_dialect_python_bindings(
   ROOT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/mlir_standalone"
   TD_FILE dialects/StandaloneOps.td
   SOURCES
-    dialects/standalone.py
+    dialects/standalone_pybind11.py
+    dialects/standalone_nanobind.py
   DIALECT_NAME standalone)
 
-declare_mlir_python_extension(StandalonePythonSources.Extension
-  MODULE_NAME _standaloneDialects
+
+declare_mlir_python_extension(StandalonePythonSources.Pybind11Extension
+  MODULE_NAME _standaloneDialectsPybind11
+  ADD_TO_PARENT StandalonePythonSources
+  SOURCES
+    StandaloneExtensionPybind11.cpp
+  EMBED_CAPI_LINK_LIBS
+    StandaloneCAPI
+  PYTHON_BINDINGS_LIBRARY pybind11
+)
+
+declare_mlir_python_extension(StandalonePythonSources.NanobindExtension
+  MODULE_NAME _standaloneDialectsNanobind
   ADD_TO_PARENT StandalonePythonSources
   SOURCES
-    StandaloneExtension.cpp
+    StandaloneExtensionNanobind.cpp
   EMBED_CAPI_LINK_LIBS
     StandaloneCAPI
+  PYTHON_BINDINGS_LIBRARY nanobind
 )
 
+
 ################################################################################
 # Common CAPI
 ################################################################################

diff  --git a/mlir/examples/standalone/python/StandaloneExtensionNanobind.cpp b/mlir/examples/standalone/python/StandaloneExtensionNanobind.cpp
new file mode 100644
index 00000000000000..6d83dc585dcd1d
--- /dev/null
+++ b/mlir/examples/standalone/python/StandaloneExtensionNanobind.cpp
@@ -0,0 +1,35 @@
+//===- StandaloneExtension.cpp - Extension module -------------------------===//
+//
+// This is the nanobind version of the example module. There is also a pybind11
+// example in StandaloneExtensionPybind11.cpp.
+//
+// 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 <nanobind/nanobind.h>
+
+#include "Standalone-c/Dialects.h"
+#include "mlir/Bindings/Python/NanobindAdaptors.h"
+
+namespace nb = nanobind;
+
+NB_MODULE(_standaloneDialectsNanobind, m) {
+  //===--------------------------------------------------------------------===//
+  // standalone dialect
+  //===--------------------------------------------------------------------===//
+  auto standaloneM = m.def_submodule("standalone");
+
+  standaloneM.def(
+      "register_dialect",
+      [](MlirContext context, bool load) {
+        MlirDialectHandle handle = mlirGetDialectHandle__standalone__();
+        mlirDialectHandleRegisterDialect(handle, context);
+        if (load) {
+          mlirDialectHandleLoadDialect(handle, context);
+        }
+      },
+      nb::arg("context").none() = nb::none(), nb::arg("load") = true);
+}

diff  --git a/mlir/examples/standalone/python/StandaloneExtension.cpp b/mlir/examples/standalone/python/StandaloneExtensionPybind11.cpp
similarity index 81%
rename from mlir/examples/standalone/python/StandaloneExtension.cpp
rename to mlir/examples/standalone/python/StandaloneExtensionPybind11.cpp
index 5e83060cd48d82..397db4c20e7432 100644
--- a/mlir/examples/standalone/python/StandaloneExtension.cpp
+++ b/mlir/examples/standalone/python/StandaloneExtensionPybind11.cpp
@@ -1,4 +1,7 @@
-//===- StandaloneExtension.cpp - Extension module -------------------------===//
+//===- StandaloneExtensionPybind11.cpp - Extension module -----------------===//
+//
+// This is the pybind11 version of the example module. There is also a nanobind
+// example in StandaloneExtensionNanobind.cpp.
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -11,7 +14,7 @@
 
 using namespace mlir::python::adaptors;
 
-PYBIND11_MODULE(_standaloneDialects, m) {
+PYBIND11_MODULE(_standaloneDialectsPybind11, m) {
   //===--------------------------------------------------------------------===//
   // standalone dialect
   //===--------------------------------------------------------------------===//

diff  --git a/mlir/examples/standalone/python/mlir_standalone/dialects/standalone.py b/mlir/examples/standalone/python/mlir_standalone/dialects/standalone_nanobind.py
similarity index 78%
rename from mlir/examples/standalone/python/mlir_standalone/dialects/standalone.py
rename to mlir/examples/standalone/python/mlir_standalone/dialects/standalone_nanobind.py
index c958b2ac193682..6218720951c82a 100644
--- a/mlir/examples/standalone/python/mlir_standalone/dialects/standalone.py
+++ b/mlir/examples/standalone/python/mlir_standalone/dialects/standalone_nanobind.py
@@ -3,4 +3,4 @@
 #  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 from ._standalone_ops_gen import *
-from .._mlir_libs._standaloneDialects.standalone import *
+from .._mlir_libs._standaloneDialectsNanobind.standalone import *

diff  --git a/mlir/examples/standalone/python/mlir_standalone/dialects/standalone_pybind11.py b/mlir/examples/standalone/python/mlir_standalone/dialects/standalone_pybind11.py
new file mode 100644
index 00000000000000..bfb98e404e13f2
--- /dev/null
+++ b/mlir/examples/standalone/python/mlir_standalone/dialects/standalone_pybind11.py
@@ -0,0 +1,6 @@
+#  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
+
+from ._standalone_ops_gen import *
+from .._mlir_libs._standaloneDialectsPybind11.standalone import *

diff  --git a/mlir/examples/standalone/test/python/smoketest.py b/mlir/examples/standalone/test/python/smoketest.py
index 08e08cbd2fe24c..bd40c65d161645 100644
--- a/mlir/examples/standalone/test/python/smoketest.py
+++ b/mlir/examples/standalone/test/python/smoketest.py
@@ -1,7 +1,17 @@
-# RUN: %python %s | FileCheck %s
+# RUN: %python %s pybind11 | FileCheck %s
+# RUN: %python %s nanobind | FileCheck %s
 
+import sys
 from mlir_standalone.ir import *
-from mlir_standalone.dialects import builtin as builtin_d, standalone as standalone_d
+from mlir_standalone.dialects import builtin as builtin_d
+
+if sys.argv[1] == "pybind11":
+    from mlir_standalone.dialects import standalone_pybind11 as standalone_d
+elif sys.argv[1] == "nanobind":
+    from mlir_standalone.dialects import standalone_nanobind as standalone_d
+else:
+    raise ValueError("Expected either pybind11 or nanobind as arguments")
+
 
 with Context():
     standalone_d.register_dialect()

diff  --git a/mlir/include/mlir/Bindings/Python/Diagnostics.h b/mlir/include/mlir/Bindings/Python/Diagnostics.h
new file mode 100644
index 00000000000000..ea80e14dde0f3a
--- /dev/null
+++ b/mlir/include/mlir/Bindings/Python/Diagnostics.h
@@ -0,0 +1,59 @@
+//===- Diagnostics.h - Helpers for diagnostics in Python bindings ---------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_BINDINGS_PYTHON_DIAGNOSTICS_H
+#define MLIR_BINDINGS_PYTHON_DIAGNOSTICS_H
+
+#include <cassert>
+#include <string>
+
+#include "mlir-c/Diagnostics.h"
+#include "mlir-c/IR.h"
+#include "llvm/ADT/StringRef.h"
+
+namespace mlir {
+namespace python {
+
+/// RAII scope intercepting all diagnostics into a string. The message must be
+/// checked before this goes out of scope.
+class CollectDiagnosticsToStringScope {
+public:
+  explicit CollectDiagnosticsToStringScope(MlirContext ctx) : context(ctx) {
+    handlerID = mlirContextAttachDiagnosticHandler(ctx, &handler, &errorMessage,
+                                                   /*deleteUserData=*/nullptr);
+  }
+  ~CollectDiagnosticsToStringScope() {
+    assert(errorMessage.empty() && "unchecked error message");
+    mlirContextDetachDiagnosticHandler(context, handlerID);
+  }
+
+  [[nodiscard]] std::string takeMessage() { return std::move(errorMessage); }
+
+private:
+  static MlirLogicalResult handler(MlirDiagnostic diag, void *data) {
+    auto printer = +[](MlirStringRef message, void *data) {
+      *static_cast<std::string *>(data) +=
+          llvm::StringRef(message.data, message.length);
+    };
+    MlirLocation loc = mlirDiagnosticGetLocation(diag);
+    *static_cast<std::string *>(data) += "at ";
+    mlirLocationPrint(loc, printer, data);
+    *static_cast<std::string *>(data) += ": ";
+    mlirDiagnosticPrint(diag, printer, data);
+    return mlirLogicalResultSuccess();
+  }
+
+  MlirContext context;
+  MlirDiagnosticHandlerID handlerID;
+  std::string errorMessage = "";
+};
+
+} // namespace python
+} // namespace mlir
+
+#endif // MLIR_BINDINGS_PYTHON_DIAGNOSTICS_H

diff  --git a/mlir/include/mlir/Bindings/Python/NanobindAdaptors.h b/mlir/include/mlir/Bindings/Python/NanobindAdaptors.h
new file mode 100644
index 00000000000000..5e01cebcb09c91
--- /dev/null
+++ b/mlir/include/mlir/Bindings/Python/NanobindAdaptors.h
@@ -0,0 +1,671 @@
+//===- NanobindAdaptors.h - Interop with MLIR APIs via nanobind -----------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// This file contains adaptors for clients of the core MLIR Python APIs to
+// interop via MLIR CAPI types, using nanobind. The facilities here do not
+// depend on implementation details of the MLIR Python API and do not introduce
+// C++-level dependencies with it (requiring only Python and CAPI-level
+// dependencies).
+//
+// It is encouraged to be used both in-tree and out-of-tree. For in-tree use
+// cases, it should be used for dialect implementations (versus relying on
+// Pybind-based internals of the core libraries).
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_BINDINGS_PYTHON_NANOBINDADAPTORS_H
+#define MLIR_BINDINGS_PYTHON_NANOBINDADAPTORS_H
+
+#include <nanobind/nanobind.h>
+#include <nanobind/stl/string.h>
+
+#include <cstdint>
+
+#include "mlir-c/Bindings/Python/Interop.h"
+#include "mlir-c/Diagnostics.h"
+#include "mlir-c/IR.h"
+#include "llvm/ADT/Twine.h"
+
+// Raw CAPI type casters need to be declared before use, so always include them
+// first.
+namespace nanobind {
+namespace detail {
+
+/// Helper to convert a presumed MLIR API object to a capsule, accepting either
+/// an explicit Capsule (which can happen when two C APIs are communicating
+/// directly via Python) or indirectly by querying the MLIR_PYTHON_CAPI_PTR_ATTR
+/// attribute (through which supported MLIR Python API objects export their
+/// contained API pointer as a capsule). Throws a type error if the object is
+/// neither. This is intended to be used from type casters, which are invoked
+/// with a raw handle (unowned). The returned object's lifetime may not extend
+/// beyond the apiObject handle without explicitly having its refcount increased
+/// (i.e. on return).
+static nanobind::object mlirApiObjectToCapsule(nanobind::handle apiObject) {
+  if (PyCapsule_CheckExact(apiObject.ptr()))
+    return nanobind::borrow<nanobind::object>(apiObject);
+  if (!nanobind::hasattr(apiObject, MLIR_PYTHON_CAPI_PTR_ATTR)) {
+    std::string repr = nanobind::cast<std::string>(nanobind::repr(apiObject));
+    throw nanobind::type_error(
+        (llvm::Twine("Expected an MLIR object (got ") + repr + ").")
+            .str()
+            .c_str());
+  }
+  return apiObject.attr(MLIR_PYTHON_CAPI_PTR_ATTR);
+}
+
+// Note: Currently all of the following support cast from nanobind::object to
+// the Mlir* C-API type, but only a few light-weight, context-bound ones
+// implicitly cast the other way because the use case has not yet emerged and
+// ownership is unclear.
+
+/// Casts object <-> MlirAffineMap.
+template <>
+struct type_caster<MlirAffineMap> {
+  NB_TYPE_CASTER(MlirAffineMap, const_name("MlirAffineMap"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToAffineMap(capsule.ptr());
+    if (mlirAffineMapIsNull(value)) {
+      return false;
+    }
+    return !mlirAffineMapIsNull(value);
+  }
+  static handle from_cpp(MlirAffineMap v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonAffineMapToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("AffineMap")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  }
+};
+
+/// Casts object <-> MlirAttribute.
+template <>
+struct type_caster<MlirAttribute> {
+  NB_TYPE_CASTER(MlirAttribute, const_name("MlirAttribute"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToAttribute(capsule.ptr());
+    return !mlirAttributeIsNull(value);
+  }
+  static handle from_cpp(MlirAttribute v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonAttributeToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("Attribute")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .attr(MLIR_PYTHON_MAYBE_DOWNCAST_ATTR)()
+        .release();
+  }
+};
+
+/// Casts object -> MlirBlock.
+template <>
+struct type_caster<MlirBlock> {
+  NB_TYPE_CASTER(MlirBlock, const_name("MlirBlock"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToBlock(capsule.ptr());
+    return !mlirBlockIsNull(value);
+  }
+};
+
+/// Casts object -> MlirContext.
+template <>
+struct type_caster<MlirContext> {
+  NB_TYPE_CASTER(MlirContext, const_name("MlirContext"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    if (src.is_none()) {
+      // Gets the current thread-bound context.
+      // TODO: This raises an error of "No current context" currently.
+      // Update the implementation to pretty-print the helpful error that the
+      // core implementations print in this case.
+      src = nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+                .attr("Context")
+                .attr("current");
+    }
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToContext(capsule.ptr());
+    return !mlirContextIsNull(value);
+  }
+};
+
+/// Casts object <-> MlirDialectRegistry.
+template <>
+struct type_caster<MlirDialectRegistry> {
+  NB_TYPE_CASTER(MlirDialectRegistry, const_name("MlirDialectRegistry"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToDialectRegistry(capsule.ptr());
+    return !mlirDialectRegistryIsNull(value);
+  }
+  static handle from_cpp(MlirDialectRegistry v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    nanobind::object capsule = nanobind::steal<nanobind::object>(
+        mlirPythonDialectRegistryToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("DialectRegistry")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  }
+};
+
+/// Casts object <-> MlirLocation.
+template <>
+struct type_caster<MlirLocation> {
+  NB_TYPE_CASTER(MlirLocation, const_name("MlirLocation"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    if (src.is_none()) {
+      // Gets the current thread-bound context.
+      src = nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+                .attr("Location")
+                .attr("current");
+    }
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToLocation(capsule.ptr());
+    return !mlirLocationIsNull(value);
+  }
+  static handle from_cpp(MlirLocation v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonLocationToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("Location")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  }
+};
+
+/// Casts object <-> MlirModule.
+template <>
+struct type_caster<MlirModule> {
+  NB_TYPE_CASTER(MlirModule, const_name("MlirModule"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToModule(capsule.ptr());
+    return !mlirModuleIsNull(value);
+  }
+  static handle from_cpp(MlirModule v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonModuleToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("Module")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  };
+};
+
+/// Casts object <-> MlirFrozenRewritePatternSet.
+template <>
+struct type_caster<MlirFrozenRewritePatternSet> {
+  NB_TYPE_CASTER(MlirFrozenRewritePatternSet,
+                 const_name("MlirFrozenRewritePatternSet"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToFrozenRewritePatternSet(capsule.ptr());
+    return value.ptr != nullptr;
+  }
+  static handle from_cpp(MlirFrozenRewritePatternSet v, rv_policy, handle) {
+    nanobind::object capsule = nanobind::steal<nanobind::object>(
+        mlirPythonFrozenRewritePatternSetToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("rewrite"))
+        .attr("FrozenRewritePatternSet")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  };
+};
+
+/// Casts object <-> MlirOperation.
+template <>
+struct type_caster<MlirOperation> {
+  NB_TYPE_CASTER(MlirOperation, const_name("MlirOperation"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToOperation(capsule.ptr());
+    return !mlirOperationIsNull(value);
+  }
+  static handle from_cpp(MlirOperation v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    if (v.ptr == nullptr)
+      return nanobind::none();
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonOperationToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("Operation")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  };
+};
+
+/// Casts object <-> MlirValue.
+template <>
+struct type_caster<MlirValue> {
+  NB_TYPE_CASTER(MlirValue, const_name("MlirValue"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToValue(capsule.ptr());
+    return !mlirValueIsNull(value);
+  }
+  static handle from_cpp(MlirValue v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    if (v.ptr == nullptr)
+      return nanobind::none();
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonValueToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("Value")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .attr(MLIR_PYTHON_MAYBE_DOWNCAST_ATTR)()
+        .release();
+  };
+};
+
+/// Casts object -> MlirPassManager.
+template <>
+struct type_caster<MlirPassManager> {
+  NB_TYPE_CASTER(MlirPassManager, const_name("MlirPassManager"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToPassManager(capsule.ptr());
+    return !mlirPassManagerIsNull(value);
+  }
+};
+
+/// Casts object <-> MlirTypeID.
+template <>
+struct type_caster<MlirTypeID> {
+  NB_TYPE_CASTER(MlirTypeID, const_name("MlirTypeID"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToTypeID(capsule.ptr());
+    return !mlirTypeIDIsNull(value);
+  }
+  static handle from_cpp(MlirTypeID v, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    if (v.ptr == nullptr)
+      return nanobind::none();
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonTypeIDToCapsule(v));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("TypeID")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .release();
+  };
+};
+
+/// Casts object <-> MlirType.
+template <>
+struct type_caster<MlirType> {
+  NB_TYPE_CASTER(MlirType, const_name("MlirType"));
+  bool from_python(handle src, uint8_t flags, cleanup_list *cleanup) {
+    nanobind::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToType(capsule.ptr());
+    return !mlirTypeIsNull(value);
+  }
+  static handle from_cpp(MlirType t, rv_policy,
+                         cleanup_list *cleanup) noexcept {
+    nanobind::object capsule =
+        nanobind::steal<nanobind::object>(mlirPythonTypeToCapsule(t));
+    return nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+        .attr("Type")
+        .attr(MLIR_PYTHON_CAPI_FACTORY_ATTR)(capsule)
+        .attr(MLIR_PYTHON_MAYBE_DOWNCAST_ATTR)()
+        .release();
+  }
+};
+
+} // namespace detail
+} // namespace nanobind
+
+namespace mlir {
+namespace python {
+namespace nanobind_adaptors {
+
+/// Provides a facility like nanobind::class_ for defining a new class in a
+/// scope, but this allows extension of an arbitrary Python class, defining
+/// methods on it is a similar way. Classes defined in this way are very similar
+/// to if defined in Python in the usual way but use nanobind machinery to
+/// do it. These are not "real" nanobind classes but pure Python classes
+/// with no relation to a concrete C++ class.
+///
+/// Derived from a discussion upstream:
+///   https://github.com/pybind/pybind11/issues/1193
+///   (plus a fair amount of extra curricular poking)
+///   TODO: If this proves useful, see about including it in nanobind.
+class pure_subclass {
+public:
+  pure_subclass(nanobind::handle scope, const char *derivedClassName,
+                const nanobind::object &superClass) {
+    nanobind::object pyType =
+        nanobind::borrow<nanobind::object>((PyObject *)&PyType_Type);
+    nanobind::object metaclass = pyType(superClass);
+    nanobind::dict attributes;
+
+    thisClass = metaclass(derivedClassName, nanobind::make_tuple(superClass),
+                          attributes);
+    scope.attr(derivedClassName) = thisClass;
+  }
+
+  template <typename Func, typename... Extra>
+  pure_subclass &def(const char *name, Func &&f, const Extra &...extra) {
+    nanobind::object cf = nanobind::cpp_function(
+        std::forward<Func>(f), nanobind::name(name), nanobind::is_method(),
+        nanobind::scope(thisClass), extra...);
+    thisClass.attr(name) = cf;
+    return *this;
+  }
+
+  template <typename Func, typename... Extra>
+  pure_subclass &def_property_readonly(const char *name, Func &&f,
+                                       const Extra &...extra) {
+    nanobind::object cf = nanobind::cpp_function(
+        std::forward<Func>(f), nanobind::name(name), nanobind::is_method(),
+        nanobind::scope(thisClass), extra...);
+    auto builtinProperty =
+        nanobind::borrow<nanobind::object>((PyObject *)&PyProperty_Type);
+    thisClass.attr(name) = builtinProperty(cf);
+    return *this;
+  }
+
+  template <typename Func, typename... Extra>
+  pure_subclass &def_staticmethod(const char *name, Func &&f,
+                                  const Extra &...extra) {
+    static_assert(!std::is_member_function_pointer<Func>::value,
+                  "def_staticmethod(...) called with a non-static member "
+                  "function pointer");
+    nanobind::object cf = nanobind::cpp_function(
+        std::forward<Func>(f),
+        nanobind::name(name), // nanobind::scope(thisClass),
+        extra...);
+    thisClass.attr(name) = cf;
+    return *this;
+  }
+
+  template <typename Func, typename... Extra>
+  pure_subclass &def_classmethod(const char *name, Func &&f,
+                                 const Extra &...extra) {
+    static_assert(!std::is_member_function_pointer<Func>::value,
+                  "def_classmethod(...) called with a non-static member "
+                  "function pointer");
+    nanobind::object cf = nanobind::cpp_function(
+        std::forward<Func>(f),
+        nanobind::name(name), // nanobind::scope(thisClass),
+        extra...);
+    thisClass.attr(name) =
+        nanobind::borrow<nanobind::object>(PyClassMethod_New(cf.ptr()));
+    return *this;
+  }
+
+  nanobind::object get_class() const { return thisClass; }
+
+protected:
+  nanobind::object superClass;
+  nanobind::object thisClass;
+};
+
+/// Creates a custom subclass of mlir.ir.Attribute, implementing a casting
+/// constructor and type checking methods.
+class mlir_attribute_subclass : public pure_subclass {
+public:
+  using IsAFunctionTy = bool (*)(MlirAttribute);
+  using GetTypeIDFunctionTy = MlirTypeID (*)();
+
+  /// Subclasses by looking up the super-class dynamically.
+  mlir_attribute_subclass(nanobind::handle scope, const char *attrClassName,
+                          IsAFunctionTy isaFunction,
+                          GetTypeIDFunctionTy getTypeIDFunction = nullptr)
+      : mlir_attribute_subclass(
+            scope, attrClassName, isaFunction,
+            nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+                .attr("Attribute"),
+            getTypeIDFunction) {}
+
+  /// Subclasses with a provided mlir.ir.Attribute super-class. This must
+  /// be used if the subclass is being defined in the same extension module
+  /// as the mlir.ir class (otherwise, it will trigger a recursive
+  /// initialization).
+  mlir_attribute_subclass(nanobind::handle scope, const char *typeClassName,
+                          IsAFunctionTy isaFunction,
+                          const nanobind::object &superCls,
+                          GetTypeIDFunctionTy getTypeIDFunction = nullptr)
+      : pure_subclass(scope, typeClassName, superCls) {
+    // Casting constructor. Note that it hard, if not impossible, to properly
+    // call chain to parent `__init__` in nanobind due to its special handling
+    // for init functions that don't have a fully constructed self-reference,
+    // which makes it impossible to forward it to `__init__` of a superclass.
+    // Instead, provide a custom `__new__` and call that of a superclass, which
+    // eventually calls `__init__` of the superclass. Since attribute subclasses
+    // have no additional members, we can just return the instance thus created
+    // without amending it.
+    std::string captureTypeName(
+        typeClassName); // As string in case if typeClassName is not static.
+    nanobind::object newCf = nanobind::cpp_function(
+        [superCls, isaFunction, captureTypeName](
+            nanobind::object cls, nanobind::object otherAttribute) {
+          MlirAttribute rawAttribute =
+              nanobind::cast<MlirAttribute>(otherAttribute);
+          if (!isaFunction(rawAttribute)) {
+            auto origRepr =
+                nanobind::cast<std::string>(nanobind::repr(otherAttribute));
+            throw std::invalid_argument(
+                (llvm::Twine("Cannot cast attribute to ") + captureTypeName +
+                 " (from " + origRepr + ")")
+                    .str());
+          }
+          nanobind::object self = superCls.attr("__new__")(cls, otherAttribute);
+          return self;
+        },
+        nanobind::name("__new__"), nanobind::arg("cls"),
+        nanobind::arg("cast_from_attr"));
+    thisClass.attr("__new__") = newCf;
+
+    // 'isinstance' method.
+    def_staticmethod(
+        "isinstance",
+        [isaFunction](MlirAttribute other) { return isaFunction(other); },
+        nanobind::arg("other_attribute"));
+    def("__repr__", [superCls, captureTypeName](nanobind::object self) {
+      return nanobind::repr(superCls(self))
+          .attr("replace")(superCls.attr("__name__"), captureTypeName);
+    });
+    if (getTypeIDFunction) {
+      def_staticmethod("get_static_typeid",
+                       [getTypeIDFunction]() { return getTypeIDFunction(); });
+      nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+          .attr(MLIR_PYTHON_CAPI_TYPE_CASTER_REGISTER_ATTR)(
+              getTypeIDFunction())(nanobind::cpp_function(
+              [thisClass = thisClass](const nanobind::object &mlirAttribute) {
+                return thisClass(mlirAttribute);
+              }));
+    }
+  }
+};
+
+/// Creates a custom subclass of mlir.ir.Type, implementing a casting
+/// constructor and type checking methods.
+class mlir_type_subclass : public pure_subclass {
+public:
+  using IsAFunctionTy = bool (*)(MlirType);
+  using GetTypeIDFunctionTy = MlirTypeID (*)();
+
+  /// Subclasses by looking up the super-class dynamically.
+  mlir_type_subclass(nanobind::handle scope, const char *typeClassName,
+                     IsAFunctionTy isaFunction,
+                     GetTypeIDFunctionTy getTypeIDFunction = nullptr)
+      : mlir_type_subclass(
+            scope, typeClassName, isaFunction,
+            nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+                .attr("Type"),
+            getTypeIDFunction) {}
+
+  /// Subclasses with a provided mlir.ir.Type super-class. This must
+  /// be used if the subclass is being defined in the same extension module
+  /// as the mlir.ir class (otherwise, it will trigger a recursive
+  /// initialization).
+  mlir_type_subclass(nanobind::handle scope, const char *typeClassName,
+                     IsAFunctionTy isaFunction,
+                     const nanobind::object &superCls,
+                     GetTypeIDFunctionTy getTypeIDFunction = nullptr)
+      : pure_subclass(scope, typeClassName, superCls) {
+    // Casting constructor. Note that it hard, if not impossible, to properly
+    // call chain to parent `__init__` in nanobind due to its special handling
+    // for init functions that don't have a fully constructed self-reference,
+    // which makes it impossible to forward it to `__init__` of a superclass.
+    // Instead, provide a custom `__new__` and call that of a superclass, which
+    // eventually calls `__init__` of the superclass. Since attribute subclasses
+    // have no additional members, we can just return the instance thus created
+    // without amending it.
+    std::string captureTypeName(
+        typeClassName); // As string in case if typeClassName is not static.
+    nanobind::object newCf = nanobind::cpp_function(
+        [superCls, isaFunction, captureTypeName](nanobind::object cls,
+                                                 nanobind::object otherType) {
+          MlirType rawType = nanobind::cast<MlirType>(otherType);
+          if (!isaFunction(rawType)) {
+            auto origRepr =
+                nanobind::cast<std::string>(nanobind::repr(otherType));
+            throw std::invalid_argument((llvm::Twine("Cannot cast type to ") +
+                                         captureTypeName + " (from " +
+                                         origRepr + ")")
+                                            .str());
+          }
+          nanobind::object self = superCls.attr("__new__")(cls, otherType);
+          return self;
+        },
+        nanobind::name("__new__"), nanobind::arg("cls"),
+        nanobind::arg("cast_from_type"));
+    thisClass.attr("__new__") = newCf;
+
+    // 'isinstance' method.
+    def_staticmethod(
+        "isinstance",
+        [isaFunction](MlirType other) { return isaFunction(other); },
+        nanobind::arg("other_type"));
+    def("__repr__", [superCls, captureTypeName](nanobind::object self) {
+      return nanobind::repr(superCls(self))
+          .attr("replace")(superCls.attr("__name__"), captureTypeName);
+    });
+    if (getTypeIDFunction) {
+      // 'get_static_typeid' method.
+      // This is modeled as a static method instead of a static property because
+      // `def_property_readonly_static` is not available in `pure_subclass` and
+      // we do not want to introduce the complexity that pybind uses to
+      // implement it.
+      def_staticmethod("get_static_typeid",
+                       [getTypeIDFunction]() { return getTypeIDFunction(); });
+      nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+          .attr(MLIR_PYTHON_CAPI_TYPE_CASTER_REGISTER_ATTR)(
+              getTypeIDFunction())(nanobind::cpp_function(
+              [thisClass = thisClass](const nanobind::object &mlirType) {
+                return thisClass(mlirType);
+              }));
+    }
+  }
+};
+
+/// Creates a custom subclass of mlir.ir.Value, implementing a casting
+/// constructor and type checking methods.
+class mlir_value_subclass : public pure_subclass {
+public:
+  using IsAFunctionTy = bool (*)(MlirValue);
+
+  /// Subclasses by looking up the super-class dynamically.
+  mlir_value_subclass(nanobind::handle scope, const char *valueClassName,
+                      IsAFunctionTy isaFunction)
+      : mlir_value_subclass(
+            scope, valueClassName, isaFunction,
+            nanobind::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+                .attr("Value")) {}
+
+  /// Subclasses with a provided mlir.ir.Value super-class. This must
+  /// be used if the subclass is being defined in the same extension module
+  /// as the mlir.ir class (otherwise, it will trigger a recursive
+  /// initialization).
+  mlir_value_subclass(nanobind::handle scope, const char *valueClassName,
+                      IsAFunctionTy isaFunction,
+                      const nanobind::object &superCls)
+      : pure_subclass(scope, valueClassName, superCls) {
+    // Casting constructor. Note that it hard, if not impossible, to properly
+    // call chain to parent `__init__` in nanobind due to its special handling
+    // for init functions that don't have a fully constructed self-reference,
+    // which makes it impossible to forward it to `__init__` of a superclass.
+    // Instead, provide a custom `__new__` and call that of a superclass, which
+    // eventually calls `__init__` of the superclass. Since attribute subclasses
+    // have no additional members, we can just return the instance thus created
+    // without amending it.
+    std::string captureValueName(
+        valueClassName); // As string in case if valueClassName is not static.
+    nanobind::object newCf = nanobind::cpp_function(
+        [superCls, isaFunction, captureValueName](nanobind::object cls,
+                                                  nanobind::object otherValue) {
+          MlirValue rawValue = nanobind::cast<MlirValue>(otherValue);
+          if (!isaFunction(rawValue)) {
+            auto origRepr =
+                nanobind::cast<std::string>(nanobind::repr(otherValue));
+            throw std::invalid_argument((llvm::Twine("Cannot cast value to ") +
+                                         captureValueName + " (from " +
+                                         origRepr + ")")
+                                            .str());
+          }
+          nanobind::object self = superCls.attr("__new__")(cls, otherValue);
+          return self;
+        },
+        nanobind::name("__new__"), nanobind::arg("cls"),
+        nanobind::arg("cast_from_value"));
+    thisClass.attr("__new__") = newCf;
+
+    // 'isinstance' method.
+    def_staticmethod(
+        "isinstance",
+        [isaFunction](MlirValue other) { return isaFunction(other); },
+        nanobind::arg("other_value"));
+  }
+};
+
+} // namespace nanobind_adaptors
+
+/// RAII scope intercepting all diagnostics into a string. The message must be
+/// checked before this goes out of scope.
+class CollectDiagnosticsToStringScope {
+public:
+  explicit CollectDiagnosticsToStringScope(MlirContext ctx) : context(ctx) {
+    handlerID = mlirContextAttachDiagnosticHandler(ctx, &handler, &errorMessage,
+                                                   /*deleteUserData=*/nullptr);
+  }
+  ~CollectDiagnosticsToStringScope() {
+    assert(errorMessage.empty() && "unchecked error message");
+    mlirContextDetachDiagnosticHandler(context, handlerID);
+  }
+
+  [[nodiscard]] std::string takeMessage() { return std::move(errorMessage); }
+
+private:
+  static MlirLogicalResult handler(MlirDiagnostic diag, void *data) {
+    auto printer = +[](MlirStringRef message, void *data) {
+      *static_cast<std::string *>(data) +=
+          llvm::StringRef(message.data, message.length);
+    };
+    MlirLocation loc = mlirDiagnosticGetLocation(diag);
+    *static_cast<std::string *>(data) += "at ";
+    mlirLocationPrint(loc, printer, data);
+    *static_cast<std::string *>(data) += ": ";
+    mlirDiagnosticPrint(diag, printer, data);
+    return mlirLogicalResultSuccess();
+  }
+
+  MlirContext context;
+  MlirDiagnosticHandlerID handlerID;
+  std::string errorMessage = "";
+};
+
+} // namespace python
+} // namespace mlir
+
+#endif // MLIR_BINDINGS_PYTHON_NANOBINDADAPTORS_H

diff  --git a/mlir/include/mlir/Bindings/Python/PybindAdaptors.h b/mlir/include/mlir/Bindings/Python/PybindAdaptors.h
index df4b9bf713592d..c8233355d1d67b 100644
--- a/mlir/include/mlir/Bindings/Python/PybindAdaptors.h
+++ b/mlir/include/mlir/Bindings/Python/PybindAdaptors.h
@@ -1,4 +1,4 @@
-//===- PybindAdaptors.h - Adaptors for interop with MLIR APIs -------------===//
+//===- PybindAdaptors.h - Interop with MLIR APIs via pybind11 -------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -6,9 +6,10 @@
 //
 //===----------------------------------------------------------------------===//
 // This file contains adaptors for clients of the core MLIR Python APIs to
-// interop via MLIR CAPI types. The facilities here do not depend on
-// implementation details of the MLIR Python API and do not introduce C++-level
-// dependencies with it (requiring only Python and CAPI-level dependencies).
+// interop via MLIR CAPI types, using pybind11. The facilities here do not
+// depend on implementation details of the MLIR Python API and do not introduce
+// C++-level dependencies with it (requiring only Python and CAPI-level
+// dependencies).
 //
 // It is encouraged to be used both in-tree and out-of-tree. For in-tree use
 // cases, it should be used for dialect implementations (versus relying on
@@ -611,40 +612,6 @@ class mlir_value_subclass : public pure_subclass {
 
 } // namespace adaptors
 
-/// RAII scope intercepting all diagnostics into a string. The message must be
-/// checked before this goes out of scope.
-class CollectDiagnosticsToStringScope {
-public:
-  explicit CollectDiagnosticsToStringScope(MlirContext ctx) : context(ctx) {
-    handlerID = mlirContextAttachDiagnosticHandler(ctx, &handler, &errorMessage,
-                                                   /*deleteUserData=*/nullptr);
-  }
-  ~CollectDiagnosticsToStringScope() {
-    assert(errorMessage.empty() && "unchecked error message");
-    mlirContextDetachDiagnosticHandler(context, handlerID);
-  }
-
-  [[nodiscard]] std::string takeMessage() { return std::move(errorMessage); }
-
-private:
-  static MlirLogicalResult handler(MlirDiagnostic diag, void *data) {
-    auto printer = +[](MlirStringRef message, void *data) {
-      *static_cast<std::string *>(data) +=
-          llvm::StringRef(message.data, message.length);
-    };
-    MlirLocation loc = mlirDiagnosticGetLocation(diag);
-    *static_cast<std::string *>(data) += "at ";
-    mlirLocationPrint(loc, printer, data);
-    *static_cast<std::string *>(data) += ": ";
-    mlirDiagnosticPrint(diag, printer, data);
-    return mlirLogicalResultSuccess();
-  }
-
-  MlirContext context;
-  MlirDiagnosticHandlerID handlerID;
-  std::string errorMessage = "";
-};
-
 } // namespace python
 } // namespace mlir
 

diff  --git a/mlir/lib/Bindings/Python/DialectLLVM.cpp b/mlir/lib/Bindings/Python/DialectLLVM.cpp
index 42a4c8c0793ba8..cccf1370b8cc87 100644
--- a/mlir/lib/Bindings/Python/DialectLLVM.cpp
+++ b/mlir/lib/Bindings/Python/DialectLLVM.cpp
@@ -6,11 +6,13 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <string>
+
 #include "mlir-c/Dialect/LLVM.h"
 #include "mlir-c/IR.h"
 #include "mlir-c/Support.h"
+#include "mlir/Bindings/Python/Diagnostics.h"
 #include "mlir/Bindings/Python/PybindAdaptors.h"
-#include <string>
 
 namespace py = pybind11;
 using namespace llvm;

diff  --git a/mlir/lib/Bindings/Python/TransformInterpreter.cpp b/mlir/lib/Bindings/Python/TransformInterpreter.cpp
index f6b4532b1b6be4..0c8c0e0a965aa7 100644
--- a/mlir/lib/Bindings/Python/TransformInterpreter.cpp
+++ b/mlir/lib/Bindings/Python/TransformInterpreter.cpp
@@ -10,14 +10,15 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include <pybind11/detail/common.h>
+#include <pybind11/pybind11.h>
+
 #include "mlir-c/Dialect/Transform/Interpreter.h"
 #include "mlir-c/IR.h"
 #include "mlir-c/Support.h"
+#include "mlir/Bindings/Python/Diagnostics.h"
 #include "mlir/Bindings/Python/PybindAdaptors.h"
 
-#include <pybind11/detail/common.h>
-#include <pybind11/pybind11.h>
-
 namespace py = pybind11;
 
 namespace {

diff  --git a/mlir/python/CMakeLists.txt b/mlir/python/CMakeLists.txt
index 23187f256455bb..e1b870b53ad25c 100644
--- a/mlir/python/CMakeLists.txt
+++ b/mlir/python/CMakeLists.txt
@@ -683,7 +683,9 @@ if(MLIR_INCLUDE_TESTS)
     MLIRPythonTestSources.Dialects.PythonTest
     ROOT_DIR "${CMAKE_CURRENT_SOURCE_DIR}/mlir"
     ADD_TO_PARENT MLIRPythonTestSources.Dialects
-    SOURCES dialects/python_test.py)
+    SOURCES
+      dialects/python_test.py
+  )
   set(LLVM_TARGET_DEFINITIONS
     "${MLIR_MAIN_SRC_DIR}/test/python/python_test_ops.td")
   mlir_tablegen(
@@ -697,12 +699,25 @@ if(MLIR_INCLUDE_TESTS)
     ADD_TO_PARENT MLIRPythonTestSources.Dialects.PythonTest
     SOURCES "dialects/_python_test_ops_gen.py")
 
-  declare_mlir_python_extension(MLIRPythonTestSources.PythonTestExtension
-    MODULE_NAME _mlirPythonTest
+  declare_mlir_python_extension(MLIRPythonTestSources.PythonTestExtensionPybind11
+    MODULE_NAME _mlirPythonTestPybind11
+    ADD_TO_PARENT MLIRPythonTestSources.Dialects
+    ROOT_DIR "${MLIR_SOURCE_DIR}/test/python/lib"
+    PYTHON_BINDINGS_LIBRARY pybind11
+    SOURCES
+      PythonTestModulePybind11.cpp
+    PRIVATE_LINK_LIBS
+      LLVMSupport
+    EMBED_CAPI_LINK_LIBS
+      MLIRCAPIPythonTestDialect
+  )
+  declare_mlir_python_extension(MLIRPythonTestSources.PythonTestExtensionNanobind
+    MODULE_NAME _mlirPythonTestNanobind
     ADD_TO_PARENT MLIRPythonTestSources.Dialects
     ROOT_DIR "${MLIR_SOURCE_DIR}/test/python/lib"
+    PYTHON_BINDINGS_LIBRARY nanobind
     SOURCES
-      PythonTestModule.cpp
+      PythonTestModuleNanobind.cpp
     PRIVATE_LINK_LIBS
       LLVMSupport
     EMBED_CAPI_LINK_LIBS

diff  --git a/mlir/python/mlir/dialects/python_test.py b/mlir/python/mlir/dialects/python_test.py
index b5baa80bc767fb..9380896c8c06e8 100644
--- a/mlir/python/mlir/dialects/python_test.py
+++ b/mlir/python/mlir/dialects/python_test.py
@@ -3,15 +3,14 @@
 #  SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
 from ._python_test_ops_gen import *
-from .._mlir_libs._mlirPythonTest import (
-    TestAttr,
-    TestType,
-    TestTensorValue,
-    TestIntegerRankedTensorType,
-)
 
 
-def register_python_test_dialect(registry):
-    from .._mlir_libs import _mlirPythonTest
+def register_python_test_dialect(registry, use_nanobind):
+    if use_nanobind:
+        from .._mlir_libs import _mlirPythonTestNanobind
 
-    _mlirPythonTest.register_dialect(registry)
+        _mlirPythonTestNanobind.register_dialect(registry)
+    else:
+        from .._mlir_libs import _mlirPythonTestPybind11
+
+        _mlirPythonTestPybind11.register_dialect(registry)

diff  --git a/mlir/python/requirements.txt b/mlir/python/requirements.txt
index 272d066831f927..ab8a9122919e19 100644
--- a/mlir/python/requirements.txt
+++ b/mlir/python/requirements.txt
@@ -1,3 +1,4 @@
+nanobind>=2.0, <3.0
 numpy>=1.19.5, <=2.1.2
 pybind11>=2.10.0, <=2.13.6
 PyYAML>=5.4.0, <=6.0.1

diff  --git a/mlir/test/python/dialects/python_test.py b/mlir/test/python/dialects/python_test.py
index 948d1225ea489c..fd678f8321fd93 100644
--- a/mlir/test/python/dialects/python_test.py
+++ b/mlir/test/python/dialects/python_test.py
@@ -1,12 +1,33 @@
-# RUN: %PYTHON %s | FileCheck %s
+# RUN: %PYTHON %s pybind11 | FileCheck %s
+# RUN: %PYTHON %s nanobind | FileCheck %s
 
+import sys
 from mlir.ir import *
 import mlir.dialects.func as func
 import mlir.dialects.python_test as test
 import mlir.dialects.tensor as tensor
 import mlir.dialects.arith as arith
 
-test.register_python_test_dialect(get_dialect_registry())
+if sys.argv[1] == "pybind11":
+    from mlir._mlir_libs._mlirPythonTestPybind11 import (
+        TestAttr,
+        TestType,
+        TestTensorValue,
+        TestIntegerRankedTensorType,
+    )
+
+    test.register_python_test_dialect(get_dialect_registry(), use_nanobind=False)
+elif sys.argv[1] == "nanobind":
+    from mlir._mlir_libs._mlirPythonTestNanobind import (
+        TestAttr,
+        TestType,
+        TestTensorValue,
+        TestIntegerRankedTensorType,
+    )
+
+    test.register_python_test_dialect(get_dialect_registry(), use_nanobind=True)
+else:
+    raise ValueError("Expected pybind11 or nanobind as argument")
 
 
 def run(f):
@@ -308,7 +329,7 @@ def testOptionalOperandOp():
 @run
 def testCustomAttribute():
     with Context() as ctx, Location.unknown():
-        a = test.TestAttr.get()
+        a = TestAttr.get()
         # CHECK: #python_test.test_attr
         print(a)
 
@@ -325,11 +346,11 @@ def testCustomAttribute():
         print(repr(op2.test_attr))
 
         # The following cast must not assert.
-        b = test.TestAttr(a)
+        b = TestAttr(a)
 
         unit = UnitAttr.get()
         try:
-            test.TestAttr(unit)
+            TestAttr(unit)
         except ValueError as e:
             assert "Cannot cast attribute to TestAttr" in str(e)
         else:
@@ -338,7 +359,7 @@ def testCustomAttribute():
         # The following must trigger a TypeError from our adaptors and must not
         # crash.
         try:
-            test.TestAttr(42)
+            TestAttr(42)
         except TypeError as e:
             assert "Expected an MLIR object" in str(e)
         else:
@@ -347,7 +368,7 @@ def testCustomAttribute():
         # The following must trigger a TypeError from pybind (therefore, not
         # checking its message) and must not crash.
         try:
-            test.TestAttr(42, 56)
+            TestAttr(42, 56)
         except TypeError:
             pass
         else:
@@ -357,12 +378,12 @@ def testCustomAttribute():
 @run
 def testCustomType():
     with Context() as ctx:
-        a = test.TestType.get()
+        a = TestType.get()
         # CHECK: !python_test.test_type
         print(a)
 
         # The following cast must not assert.
-        b = test.TestType(a)
+        b = TestType(a)
         # Instance custom types should have typeids
         assert isinstance(b.typeid, TypeID)
         # Subclasses of ir.Type should not have a static_typeid
@@ -374,7 +395,7 @@ def testCustomType():
 
         i8 = IntegerType.get_signless(8)
         try:
-            test.TestType(i8)
+            TestType(i8)
         except ValueError as e:
             assert "Cannot cast type to TestType" in str(e)
         else:
@@ -383,7 +404,7 @@ def testCustomType():
         # The following must trigger a TypeError from our adaptors and must not
         # crash.
         try:
-            test.TestType(42)
+            TestType(42)
         except TypeError as e:
             assert "Expected an MLIR object" in str(e)
         else:
@@ -392,7 +413,7 @@ def testCustomType():
         # The following must trigger a TypeError from pybind (therefore, not
         # checking its message) and must not crash.
         try:
-            test.TestType(42, 56)
+            TestType(42, 56)
         except TypeError:
             pass
         else:
@@ -405,7 +426,7 @@ def testTensorValue():
     with Context() as ctx, Location.unknown():
         i8 = IntegerType.get_signless(8)
 
-        class Tensor(test.TestTensorValue):
+        class Tensor(TestTensorValue):
             def __str__(self):
                 return super().__str__().replace("Value", "Tensor")
 
@@ -425,9 +446,9 @@ def __str__(self):
 
             # Classes of custom types that inherit from concrete types should have
             # static_typeid
-            assert isinstance(test.TestIntegerRankedTensorType.static_typeid, TypeID)
+            assert isinstance(TestIntegerRankedTensorType.static_typeid, TypeID)
             # And it should be equal to the in-tree concrete type
-            assert test.TestIntegerRankedTensorType.static_typeid == t.type.typeid
+            assert TestIntegerRankedTensorType.static_typeid == t.type.typeid
 
             d = tensor.EmptyOp([1, 2, 3], IntegerType.get_signless(5)).result
             # CHECK: Value(%{{.*}} = tensor.empty() : tensor<1x2x3xi5>)
@@ -491,7 +512,7 @@ def inferReturnTypeComponents():
 @run
 def testCustomTypeTypeCaster():
     with Context() as ctx, Location.unknown():
-        a = test.TestType.get()
+        a = TestType.get()
         assert a.typeid is not None
 
         b = Type.parse("!python_test.test_type")
@@ -500,7 +521,7 @@ def testCustomTypeTypeCaster():
         # CHECK: TestType(!python_test.test_type)
         print(repr(b))
 
-        c = test.TestIntegerRankedTensorType.get([10, 10], 5)
+        c = TestIntegerRankedTensorType.get([10, 10], 5)
         # CHECK: tensor<10x10xi5>
         print(c)
         # CHECK: TestIntegerRankedTensorType(tensor<10x10xi5>)
@@ -511,7 +532,7 @@ def testCustomTypeTypeCaster():
 
             @register_type_caster(c.typeid)
             def type_caster(pytype):
-                return test.TestIntegerRankedTensorType(pytype)
+                return TestIntegerRankedTensorType(pytype)
 
         except RuntimeError as e:
             print(e)
@@ -530,7 +551,7 @@ def type_caster(pytype):
 
         @register_type_caster(c.typeid, replace=True)
         def type_caster(pytype):
-            return test.TestIntegerRankedTensorType(pytype)
+            return TestIntegerRankedTensorType(pytype)
 
         d = tensor.EmptyOp([10, 10], IntegerType.get_signless(5)).result
         # CHECK: tensor<10x10xi5>

diff  --git a/mlir/test/python/lib/CMakeLists.txt b/mlir/test/python/lib/CMakeLists.txt
index d7cbbfbc214772..198ed8211e773f 100644
--- a/mlir/test/python/lib/CMakeLists.txt
+++ b/mlir/test/python/lib/CMakeLists.txt
@@ -1,7 +1,8 @@
 set(LLVM_OPTIONAL_SOURCES
   PythonTestCAPI.cpp
   PythonTestDialect.cpp
-  PythonTestModule.cpp
+  PythonTestModulePybind11.cpp
+  PythonTestModuleNanobind.cpp
 )
 
 add_mlir_library(MLIRPythonTestDialect

diff  --git a/mlir/test/python/lib/PythonTestModuleNanobind.cpp b/mlir/test/python/lib/PythonTestModuleNanobind.cpp
new file mode 100644
index 00000000000000..7c504d04be0d13
--- /dev/null
+++ b/mlir/test/python/lib/PythonTestModuleNanobind.cpp
@@ -0,0 +1,121 @@
+//===- PythonTestModuleNanobind.cpp - PythonTest dialect extension --------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+// This is the nanobind edition of the PythonTest dialect module.
+//===----------------------------------------------------------------------===//
+
+#include <nanobind/nanobind.h>
+#include <nanobind/stl/vector.h>
+
+#include "PythonTestCAPI.h"
+#include "mlir-c/BuiltinAttributes.h"
+#include "mlir-c/BuiltinTypes.h"
+#include "mlir-c/IR.h"
+#include "mlir/Bindings/Python/NanobindAdaptors.h"
+
+namespace nb = nanobind;
+using namespace mlir::python::nanobind_adaptors;
+
+static bool mlirTypeIsARankedIntegerTensor(MlirType t) {
+  return mlirTypeIsARankedTensor(t) &&
+         mlirTypeIsAInteger(mlirShapedTypeGetElementType(t));
+}
+
+NB_MODULE(_mlirPythonTestNanobind, m) {
+  m.def(
+      "register_python_test_dialect",
+      [](MlirContext context, bool load) {
+        MlirDialectHandle pythonTestDialect =
+            mlirGetDialectHandle__python_test__();
+        mlirDialectHandleRegisterDialect(pythonTestDialect, context);
+        if (load) {
+          mlirDialectHandleLoadDialect(pythonTestDialect, context);
+        }
+      },
+      nb::arg("context"), nb::arg("load") = true);
+
+  m.def(
+      "register_dialect",
+      [](MlirDialectRegistry registry) {
+        MlirDialectHandle pythonTestDialect =
+            mlirGetDialectHandle__python_test__();
+        mlirDialectHandleInsertDialect(pythonTestDialect, registry);
+      },
+      nb::arg("registry"));
+
+  mlir_attribute_subclass(m, "TestAttr",
+                          mlirAttributeIsAPythonTestTestAttribute,
+                          mlirPythonTestTestAttributeGetTypeID)
+      .def_classmethod(
+          "get",
+          [](const nb::object &cls, MlirContext ctx) {
+            return cls(mlirPythonTestTestAttributeGet(ctx));
+          },
+          nb::arg("cls"), nb::arg("context").none() = nb::none());
+
+  mlir_type_subclass(m, "TestType", mlirTypeIsAPythonTestTestType,
+                     mlirPythonTestTestTypeGetTypeID)
+      .def_classmethod(
+          "get",
+          [](const nb::object &cls, MlirContext ctx) {
+            return cls(mlirPythonTestTestTypeGet(ctx));
+          },
+          nb::arg("cls"), nb::arg("context").none() = nb::none());
+
+  auto typeCls =
+      mlir_type_subclass(m, "TestIntegerRankedTensorType",
+                         mlirTypeIsARankedIntegerTensor,
+                         nb::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+                             .attr("RankedTensorType"))
+          .def_classmethod(
+              "get",
+              [](const nb::object &cls, std::vector<int64_t> shape,
+                 unsigned width, MlirContext ctx) {
+                MlirAttribute encoding = mlirAttributeGetNull();
+                return cls(mlirRankedTensorTypeGet(
+                    shape.size(), shape.data(), mlirIntegerTypeGet(ctx, width),
+                    encoding));
+              },
+              nb::arg("cls"), nb::arg("shape"), nb::arg("width"),
+              nb::arg("context").none() = nb::none());
+
+  assert(nb::hasattr(typeCls.get_class(), "static_typeid") &&
+         "TestIntegerRankedTensorType has no static_typeid");
+
+  MlirTypeID mlirRankedTensorTypeID = mlirRankedTensorTypeGetTypeID();
+
+  nb::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+      .attr(MLIR_PYTHON_CAPI_TYPE_CASTER_REGISTER_ATTR)(
+          mlirRankedTensorTypeID, nb::arg("replace") = true)(
+          nanobind::cpp_function([typeCls](const nb::object &mlirType) {
+            return typeCls.get_class()(mlirType);
+          }));
+
+  auto valueCls = mlir_value_subclass(m, "TestTensorValue",
+                                      mlirTypeIsAPythonTestTestTensorValue)
+                      .def("is_null", [](MlirValue &self) {
+                        return mlirValueIsNull(self);
+                      });
+
+  nb::module_::import_(MAKE_MLIR_PYTHON_QUALNAME("ir"))
+      .attr(MLIR_PYTHON_CAPI_VALUE_CASTER_REGISTER_ATTR)(
+          mlirRankedTensorTypeID)(
+          nanobind::cpp_function([valueCls](const nb::object &valueObj) {
+            nb::object capsule = mlirApiObjectToCapsule(valueObj);
+            MlirValue v = mlirPythonCapsuleToValue(capsule.ptr());
+            MlirType t = mlirValueGetType(v);
+            // This is hyper-specific in order to exercise/test registering a
+            // value caster from cpp (but only for a single test case; see
+            // testTensorValue python_test.py).
+            if (mlirShapedTypeHasStaticShape(t) &&
+                mlirShapedTypeGetDimSize(t, 0) == 1 &&
+                mlirShapedTypeGetDimSize(t, 1) == 2 &&
+                mlirShapedTypeGetDimSize(t, 2) == 3)
+              return valueCls.get_class()(valueObj);
+            return valueObj;
+          }));
+}

diff  --git a/mlir/test/python/lib/PythonTestModule.cpp b/mlir/test/python/lib/PythonTestModulePybind11.cpp
similarity index 96%
rename from mlir/test/python/lib/PythonTestModule.cpp
rename to mlir/test/python/lib/PythonTestModulePybind11.cpp
index a4f538dcb55944..94a5f5178d16e8 100644
--- a/mlir/test/python/lib/PythonTestModule.cpp
+++ b/mlir/test/python/lib/PythonTestModulePybind11.cpp
@@ -5,6 +5,8 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
+// This is the pybind11 edition of the PythonTest dialect module.
+//===----------------------------------------------------------------------===//
 
 #include "PythonTestCAPI.h"
 #include "mlir-c/BuiltinAttributes.h"
@@ -21,7 +23,7 @@ static bool mlirTypeIsARankedIntegerTensor(MlirType t) {
          mlirTypeIsAInteger(mlirShapedTypeGetElementType(t));
 }
 
-PYBIND11_MODULE(_mlirPythonTest, m) {
+PYBIND11_MODULE(_mlirPythonTestPybind11, m) {
   m.def(
       "register_python_test_dialect",
       [](MlirContext context, bool load) {

diff  --git a/utils/bazel/WORKSPACE b/utils/bazel/WORKSPACE
index 7baca11eed3d39..66ba1ac1b17e1e 100644
--- a/utils/bazel/WORKSPACE
+++ b/utils/bazel/WORKSPACE
@@ -148,6 +148,24 @@ maybe(
     url = "https://github.com/pybind/pybind11/archive/v2.10.3.zip",
 )
 
+maybe(
+    http_archive,
+    name = "robin_map",
+    strip_prefix = "robin-map-1.3.0",
+    sha256 = "a8424ad3b0affd4c57ed26f0f3d8a29604f0e1f2ef2089f497f614b1c94c7236",
+    build_file = "@llvm-raw//utils/bazel/third_party_build:robin_map.BUILD",
+    url = "https://github.com/Tessil/robin-map/archive/refs/tags/v1.3.0.tar.gz",
+)
+
+maybe(
+    http_archive,
+    name = "nanobind",
+    build_file = "@llvm-raw//utils/bazel/third_party_build:nanobind.BUILD",
+    sha256 = "bfbfc7e5759f1669e4ddb48752b1ddc5647d1430e94614d6f8626df1d508e65a",
+    strip_prefix = "nanobind-2.2.0",
+    url = "https://github.com/wjakob/nanobind/archive/refs/tags/v2.2.0.tar.gz",
+)
+
 load("@rules_python//python:repositories.bzl", "py_repositories", "python_register_toolchains")
 
 py_repositories()

diff  --git a/utils/bazel/llvm-project-overlay/mlir/BUILD.bazel b/utils/bazel/llvm-project-overlay/mlir/BUILD.bazel
index 179fed2f5e9a00..544becfa30b40f 100644
--- a/utils/bazel/llvm-project-overlay/mlir/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/mlir/BUILD.bazel
@@ -932,7 +932,6 @@ exports_files(
 filegroup(
     name = "MLIRBindingsPythonHeaderFiles",
     srcs = glob([
-        "lib/Bindings/Python/*.h",
         "include/mlir-c/Bindings/Python/*.h",
         "include/mlir/Bindings/Python/*.h",
     ]),
@@ -942,12 +941,10 @@ cc_library(
     name = "MLIRBindingsPythonHeaders",
     includes = [
         "include",
-        "lib/Bindings/Python",
     ],
     textual_hdrs = [":MLIRBindingsPythonHeaderFiles"],
     deps = [
         ":CAPIIRHeaders",
-        ":CAPITransformsHeaders",
         "@pybind11",
         "@rules_python//python/cc:current_py_cc_headers",
     ],
@@ -957,17 +954,41 @@ cc_library(
     name = "MLIRBindingsPythonHeadersAndDeps",
     includes = [
         "include",
-        "lib/Bindings/Python",
     ],
     textual_hdrs = [":MLIRBindingsPythonHeaderFiles"],
     deps = [
         ":CAPIIR",
-        ":CAPITransforms",
         "@pybind11",
         "@rules_python//python/cc:current_py_cc_headers",
     ],
 )
 
+cc_library(
+    name = "MLIRBindingsPythonNanobindHeaders",
+    includes = [
+        "include",
+    ],
+    textual_hdrs = [":MLIRBindingsPythonHeaderFiles"],
+    deps = [
+        ":CAPIIRHeaders",
+        "@nanobind",
+        "@rules_python//python/cc:current_py_cc_headers",
+    ],
+)
+
+cc_library(
+    name = "MLIRBindingsPythonNanobindHeadersAndDeps",
+    includes = [
+        "include",
+    ],
+    textual_hdrs = [":MLIRBindingsPythonHeaderFiles"],
+    deps = [
+        ":CAPIIR",
+        "@nanobind",
+        "@rules_python//python/cc:current_py_cc_headers",
+    ],
+)
+
 # These flags are needed for pybind11 to work.
 PYBIND11_COPTS = [
     "-fexceptions",
@@ -993,16 +1014,25 @@ filegroup(
     ],
 )
 
+filegroup(
+    name = "MLIRBindingsPythonCoreHeaders",
+    srcs = glob([
+        "lib/Bindings/Python/*.h",
+    ]),
+)
+
 cc_library(
     name = "MLIRBindingsPythonCore",
     srcs = [":MLIRBindingsPythonSourceFiles"],
     copts = PYBIND11_COPTS,
     features = PYBIND11_FEATURES,
+    textual_hdrs = [":MLIRBindingsPythonCoreHeaders"],
     deps = [
         ":CAPIAsync",
         ":CAPIDebug",
         ":CAPIIR",
         ":CAPIInterfaces",
+        ":CAPITransforms",
         ":MLIRBindingsPythonHeadersAndDeps",
         ":Support",
         ":config",
@@ -1017,10 +1047,12 @@ cc_library(
     srcs = [":MLIRBindingsPythonSourceFiles"],
     copts = PYBIND11_COPTS,
     features = PYBIND11_FEATURES,
+    textual_hdrs = [":MLIRBindingsPythonCoreHeaders"],
     deps = [
         ":CAPIAsyncHeaders",
         ":CAPIDebugHeaders",
         ":CAPIIRHeaders",
+        ":CAPITransformsHeaders",
         ":MLIRBindingsPythonHeaders",
         ":Support",
         ":config",
@@ -1050,6 +1082,9 @@ cc_binary(
     # These flags are needed for pybind11 to work.
     copts = PYBIND11_COPTS,
     features = PYBIND11_FEATURES,
+    includes = [
+        "lib/Bindings/Python",
+    ],
     linkshared = 1,
     linkstatic = 0,
     deps = [
@@ -1063,6 +1098,9 @@ cc_binary(
     srcs = ["lib/Bindings/Python/DialectLinalg.cpp"],
     copts = PYBIND11_COPTS,
     features = PYBIND11_FEATURES,
+    includes = [
+        "lib/Bindings/Python",
+    ],
     linkshared = 1,
     linkstatic = 0,
     deps = [
@@ -8448,9 +8486,9 @@ cc_library(
     hdrs = ["include/mlir/Conversion/ConvertToLLVM/ToLLVMPass.h"],
     includes = ["include"],
     deps = [
+        ":Analysis",
         ":ConversionPassIncGen",
         ":ConvertToLLVMInterface",
-        ":Analysis",
         ":IR",
         ":LLVMCommonConversion",
         ":LLVMDialect",

diff  --git a/utils/bazel/third_party_build/nanobind.BUILD b/utils/bazel/third_party_build/nanobind.BUILD
new file mode 100644
index 00000000000000..262d14a040b87e
--- /dev/null
+++ b/utils/bazel/third_party_build/nanobind.BUILD
@@ -0,0 +1,25 @@
+cc_library(
+    name = "nanobind",
+    srcs = glob(
+        [
+            "src/*.cpp",
+        ],
+        exclude = ["src/nb_combined.cpp"],
+    ),
+    defines = [
+        "NB_BUILD=1",
+        "NB_SHARED=1",
+    ],
+    includes = ["include"],
+    textual_hdrs = glob(
+        [
+            "include/**/*.h",
+            "src/*.h",
+        ],
+    ),
+    visibility = ["//visibility:public"],
+    deps = [
+        "@robin_map",
+        "@rules_python//python/cc:current_py_cc_headers",
+    ],
+)

diff  --git a/utils/bazel/third_party_build/robin_map.BUILD b/utils/bazel/third_party_build/robin_map.BUILD
new file mode 100644
index 00000000000000..b8d04beaed81f9
--- /dev/null
+++ b/utils/bazel/third_party_build/robin_map.BUILD
@@ -0,0 +1,12 @@
+cc_library(
+    name = "robin_map",
+    hdrs = [
+        "include/tsl/robin_growth_policy.h",
+        "include/tsl/robin_hash.h",
+        "include/tsl/robin_map.h",
+        "include/tsl/robin_set.h",
+    ],
+    includes = ["."],
+    strip_include_prefix = "include",
+    visibility = ["//visibility:public"],
+)


        


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