[mlir] Add PDL C & Python usage

mlir/include/mlir-c/Bindings/Python/Interop.h

@@ -39,6 +39,7 @@
 #include "mlir-c/IR.h"
 #include "mlir-c/IntegerSet.h"
 #include "mlir-c/Pass.h"
+#include "mlir-c/Rewrite.h"
 
 // The 'mlir' Python package is relocatable and supports co-existing in multiple
 // projects. Each project must define its outer package prefix with this define
@@ -284,6 +285,26 @@ static inline MlirModule mlirPythonCapsuleToModule(PyObject *capsule) {
   return module;
 }
 
+/** Creates a capsule object encapsulating the raw C-API
+ * MlirFrozenRewritePatternSet.
+ * The returned capsule does not extend or affect ownership of any Python
+ * objects that reference the module in any way. */
+static inline PyObject *
+mlirPythonFrozenRewritePatternSetToCapsule(MlirFrozenRewritePatternSet pm) {
+  return PyCapsule_New(MLIR_PYTHON_GET_WRAPPED_POINTER(pm),
+                       MLIR_PYTHON_CAPSULE_PASS_MANAGER, NULL);
+}
+
+/** Extracts an MlirFrozenRewritePatternSet from a capsule as produced from
+ * mlirPythonFrozenRewritePatternSetToCapsule. If the capsule is not of the
+ * right type, then a null module is returned. */
+static inline MlirFrozenRewritePatternSet
+mlirPythonCapsuleToFrozenRewritePatternSet(PyObject *capsule) {
+  void *ptr = PyCapsule_GetPointer(capsule, MLIR_PYTHON_CAPSULE_PASS_MANAGER);
+  MlirFrozenRewritePatternSet pm = {ptr};
+  return pm;
+}
+
 /** Creates a capsule object encapsulating the raw C-API MlirPassManager.
  * The returned capsule does not extend or affect ownership of any Python
  * objects that reference the module in any way. */

mlir/include/mlir-c/Rewrite.h

@@ -0,0 +1,60 @@
+//===-- mlir-c/Rewrite.h - Helpers for C API to Rewrites ----------*- C -*-===//
+//
+// 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 header declares the registration and creation method for
+// rewrite patterns.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_C_REWRITE_H
+#define MLIR_C_REWRITE_H
+
+#include "mlir-c/IR.h"
+#include "mlir-c/Support.h"
+#include "mlir/Config/mlir-config.h"
+
+//===----------------------------------------------------------------------===//
+/// Opaque type declarations (see mlir-c/IR.h for more details).
+//===----------------------------------------------------------------------===//
+
+#define DEFINE_C_API_STRUCT(name, storage)                                     \
+  struct name {                                                                \
+    storage *ptr;                                                              \
+  };                                                                           \
+  typedef struct name name
+
+DEFINE_C_API_STRUCT(MlirFrozenRewritePatternSet, void);
+DEFINE_C_API_STRUCT(MlirGreedyRewriteDriverConfig, void);
+DEFINE_C_API_STRUCT(MlirRewritePatternSet, void);
+
+MLIR_CAPI_EXPORTED MlirFrozenRewritePatternSet
+mlirFreezeRewritePattern(MlirRewritePatternSet op);
+
+MLIR_CAPI_EXPORTED void
+mlirFrozenRewritePatternSetDestroy(MlirFrozenRewritePatternSet op);
+
+MLIR_CAPI_EXPORTED MlirLogicalResult mlirApplyPatternsAndFoldGreedily(
+    MlirModule op, MlirFrozenRewritePatternSet patterns,
+    MlirGreedyRewriteDriverConfig);
+
+#if MLIR_ENABLE_PDL_IN_PATTERNMATCH
+DEFINE_C_API_STRUCT(MlirPDLPatternModule, void);
+
+MLIR_CAPI_EXPORTED MlirPDLPatternModule
+mlirPDLPatternModuleFromModule(MlirModule op);
+
+MLIR_CAPI_EXPORTED void mlirPDLPatternModuleDestroy(MlirPDLPatternModule op);
+
+MLIR_CAPI_EXPORTED MlirRewritePatternSet
+mlirRewritePatternSetFromPDLPatternModule(MlirPDLPatternModule op);
+#endif // MLIR_ENABLE_PDL_IN_PATTERNMATCH
+
+#undef DEFINE_C_API_STRUCT
+
+#endif // MLIR_C_REWRITE_H

mlir/include/mlir/Bindings/Python/PybindAdaptors.h

@@ -198,6 +198,27 @@ struct type_caster<MlirModule> {
   };
 };
 
+/// Casts object <-> MlirFrozenRewritePatternSet.
+template <>
+struct type_caster<MlirFrozenRewritePatternSet> {
+  PYBIND11_TYPE_CASTER(MlirFrozenRewritePatternSet,
+                       _("MlirFrozenRewritePatternSet"));
+  bool load(handle src, bool) {
+    py::object capsule = mlirApiObjectToCapsule(src);
+    value = mlirPythonCapsuleToFrozenRewritePatternSet(capsule.ptr());
+    return value.ptr != nullptr;
+  }
+  static handle cast(MlirFrozenRewritePatternSet v, return_value_policy,
+                     handle) {
+    py::object capsule = py::reinterpret_steal<py::object>(
+        mlirPythonFrozenRewritePatternSetToCapsule(v));
+    return py::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> {

mlir/lib/Bindings/Python/IRModule.h

@@ -22,6 +22,7 @@
 #include "mlir-c/Diagnostics.h"
 #include "mlir-c/IR.h"
 #include "mlir-c/IntegerSet.h"
+#include "mlir-c/Transforms.h"
 #include "mlir/Bindings/Python/PybindAdaptors.h"
 #include "llvm/ADT/DenseMap.h"
 

mlir/lib/Bindings/Python/MainModule.cpp

@@ -11,6 +11,7 @@
 #include "Globals.h"
 #include "IRModule.h"
 #include "Pass.h"
+#include "Rewrite.h"
 
 namespace py = pybind11;
 using namespace mlir;
@@ -116,6 +117,9 @@ PYBIND11_MODULE(_mlir, m) {
   populateIRInterfaces(irModule);
   populateIRTypes(irModule);
 
+  auto rewriteModule = m.def_submodule("rewrite", "MLIR Rewrite Bindings");
+  populateRewriteSubmodule(rewriteModule);
+
   // Define and populate PassManager submodule.
   auto passModule =
       m.def_submodule("passmanager", "MLIR Pass Management Bindings");

mlir/lib/Bindings/Python/Rewrite.cpp

@@ -0,0 +1,110 @@
+//===- Rewrite.cpp - Rewrite ----------------------------------------------===//
+//
+// 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 "Rewrite.h"
+
+#include "IRModule.h"
+#include "mlir-c/Bindings/Python/Interop.h"
+#include "mlir-c/Rewrite.h"
+#include "mlir/Config/mlir-config.h"
+
+namespace py = pybind11;
+using namespace mlir;
+using namespace py::literals;
+using namespace mlir::python;
+
+namespace {
+
+#if MLIR_ENABLE_PDL_IN_PATTERNMATCH
+/// Owning Wrapper around a PDLPatternModule.
+class PyPDLPatternModule {
+public:
+  PyPDLPatternModule(MlirPDLPatternModule module) : module(module) {}
+  PyPDLPatternModule(PyPDLPatternModule &&other) noexcept
+      : module(other.module) {
+    other.module.ptr = nullptr;
+  }
+  ~PyPDLPatternModule() {
+    if (module.ptr != nullptr)
+      mlirPDLPatternModuleDestroy(module);
+  }
+  MlirPDLPatternModule get() { return module; }
+
+private:
+  MlirPDLPatternModule module;
+};
+#endif // MLIR_ENABLE_PDL_IN_PATTERNMATCH
+
+/// Owning Wrapper around a FrozenRewritePatternSet.
+class PyFrozenRewritePatternSet {
+public:
+  PyFrozenRewritePatternSet(MlirFrozenRewritePatternSet set) : set(set) {}
+  PyFrozenRewritePatternSet(PyFrozenRewritePatternSet &&other) noexcept
+      : set(other.set) {
+    other.set.ptr = nullptr;
+  }
+  ~PyFrozenRewritePatternSet() {
+    if (set.ptr != nullptr)
+      mlirFrozenRewritePatternSetDestroy(set);
+  }
+  MlirFrozenRewritePatternSet get() { return set; }
+
+  pybind11::object getCapsule() {
+    return py::reinterpret_steal<py::object>(
+        mlirPythonFrozenRewritePatternSetToCapsule(get()));
+  }
+
+  static pybind11::object createFromCapsule(pybind11::object capsule) {
+    MlirFrozenRewritePatternSet rawPm =
+        mlirPythonCapsuleToFrozenRewritePatternSet(capsule.ptr());
+    if (rawPm.ptr == nullptr)
+      throw py::error_already_set();
+    return py::cast(PyFrozenRewritePatternSet(rawPm),
+                    py::return_value_policy::move);
+  }
+
+private:
+  MlirFrozenRewritePatternSet set;
+};
+
+} // namespace
+
+/// Create the `mlir.rewrite` here.
+void mlir::python::populateRewriteSubmodule(py::module &m) {
+  //----------------------------------------------------------------------------
+  // Mapping of the top-level PassManager
+  //----------------------------------------------------------------------------
+#if MLIR_ENABLE_PDL_IN_PATTERNMATCH
+  py::class_<PyPDLPatternModule>(m, "PDLModule", py::module_local())
+      .def(py::init<>([](MlirModule module) {
+             return mlirPDLPatternModuleFromModule(module);
+           }),
+           "module"_a, "Create a PDL module from the given module.")
+      .def("freeze", [](PyPDLPatternModule &self) {
+        return new PyFrozenRewritePatternSet(mlirFreezeRewritePattern(
+            mlirRewritePatternSetFromPDLPatternModule(self.get())));
+      });
+#endif // MLIR_ENABLE_PDL_IN_PATTERNMATCg
+  py::class_<PyFrozenRewritePatternSet>(m, "FrozenRewritePatternSet",
+                                        py::module_local())
+      .def_property_readonly(MLIR_PYTHON_CAPI_PTR_ATTR,
+                             &PyFrozenRewritePatternSet::getCapsule)
+      .def(MLIR_PYTHON_CAPI_FACTORY_ATTR,
+           &PyFrozenRewritePatternSet::createFromCapsule);
+  m.def(
+      "apply_patterns_and_fold_greedily",
+      [](MlirModule module, MlirFrozenRewritePatternSet set) {
+        auto status = mlirApplyPatternsAndFoldGreedily(module, set, {});
+        if (mlirLogicalResultIsFailure(status))
+          // FIXME: Not sure this is the right error to throw here.
+          throw py::value_error("pattern application failed to converge");
+      },
+      "module"_a, "set"_a,
+      "Applys the given patterns to the given module greedily while folding "
+      "results.");
+}

mlir/lib/Bindings/Python/Rewrite.h

@@ -0,0 +1,22 @@
+//===- Rewrite.h - Rewrite Submodules of 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_BINDINGS_PYTHON_REWRITE_H
+#define MLIR_BINDINGS_PYTHON_REWRITE_H
+
+#include "PybindUtils.h"
+
+namespace mlir {
+namespace python {
+
+void populateRewriteSubmodule(pybind11::module &m);
+
+} // namespace python
+} // namespace mlir
+
+#endif // MLIR_BINDINGS_PYTHON_REWRITE_H

mlir/lib/CAPI/Transforms/CMakeLists.txt

@@ -1,6 +1,9 @@
 add_mlir_upstream_c_api_library(MLIRCAPITransforms
   Passes.cpp
+  Rewrite.cpp
 
   LINK_LIBS PUBLIC
+  MLIRIR
   MLIRTransforms
+  MLIRTransformUtils
 )

mlir/lib/CAPI/Transforms/Rewrite.cpp

@@ -0,0 +1,83 @@
+//===- Rewrite.cpp - C API for Rewrite Patterns ---------------------------===//
+//
+// 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 "mlir-c/Rewrite.h"
+#include "mlir-c/Transforms.h"
+#include "mlir/CAPI/IR.h"
+#include "mlir/CAPI/Support.h"
+#include "mlir/IR/PatternMatch.h"
+#include "mlir/Rewrite/FrozenRewritePatternSet.h"
+#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
+
+using namespace mlir;
+
+inline mlir::RewritePatternSet &unwrap(MlirRewritePatternSet module) {
+  assert(module.ptr && "unexpected null module");
+  return *(static_cast<mlir::RewritePatternSet *>(module.ptr));
+}
+
+inline MlirRewritePatternSet wrap(mlir::RewritePatternSet *module) {
+  return {module};
+}
+
+inline mlir::FrozenRewritePatternSet *
+unwrap(MlirFrozenRewritePatternSet module) {
+  assert(module.ptr && "unexpected null module");
+  return static_cast<mlir::FrozenRewritePatternSet *>(module.ptr);
+}
+
+inline MlirFrozenRewritePatternSet wrap(mlir::FrozenRewritePatternSet *module) {
+  return {module};
+}
+
+MlirFrozenRewritePatternSet mlirFreezeRewritePattern(MlirRewritePatternSet op) {
+  auto *m = new mlir::FrozenRewritePatternSet(std::move(unwrap(op)));
+  op.ptr = nullptr;
+  return wrap(m);
+}
+
+void mlirFrozenRewritePatternSetDestroy(MlirFrozenRewritePatternSet op) {
+  delete unwrap(op);
+  op.ptr = nullptr;
+}
+
+MlirLogicalResult
+mlirApplyPatternsAndFoldGreedily(MlirModule op,
+                                 MlirFrozenRewritePatternSet patterns,
+                                 MlirGreedyRewriteDriverConfig) {
+  return wrap(
+      mlir::applyPatternsAndFoldGreedily(unwrap(op), *unwrap(patterns)));
+}
+
+#if MLIR_ENABLE_PDL_IN_PATTERNMATCH
+inline mlir::PDLPatternModule *unwrap(MlirPDLPatternModule module) {
+  assert(module.ptr && "unexpected null module");
+  return static_cast<mlir::PDLPatternModule *>(module.ptr);
+}
+
+inline MlirPDLPatternModule wrap(mlir::PDLPatternModule *module) {
+  return {module};
+}
+
+MlirPDLPatternModule mlirPDLPatternModuleFromModule(MlirModule op) {
+  return wrap(new mlir::PDLPatternModule(
+      mlir::OwningOpRef<mlir::ModuleOp>(unwrap(op))));
+}
+
+void mlirPDLPatternModuleDestroy(MlirPDLPatternModule op) {
+  delete unwrap(op);
+  op.ptr = nullptr;
+}
+
+MlirRewritePatternSet
+mlirRewritePatternSetFromPDLPatternModule(MlirPDLPatternModule op) {
+  auto *m = new mlir::RewritePatternSet(std::move(*unwrap(op)));
+  op.ptr = nullptr;
+  return wrap(m);
+}
+#endif // MLIR_ENABLE_PDL_IN_PATTERNMATCH

mlir/python/CMakeLists.txt

@@ -21,6 +21,7 @@ declare_mlir_python_sources(MLIRPythonSources.Core.Python
     _mlir_libs/__init__.py
     ir.py
     passmanager.py
+    rewrite.py
     dialects/_ods_common.py
 
     # The main _mlir module has submodules: include stubs from each.
@@ -448,6 +449,7 @@ declare_mlir_python_extension(MLIRPythonExtension.Core
     IRModule.cpp
     IRTypes.cpp
     Pass.cpp
+    Rewrite.cpp
 
     # Headers must be included explicitly so they are installed.
     Globals.h