[mlir][CAPI][python] expose the python bindings for linalg::isaContractionOpInterface and linalg::inferContractionDims (#134935)

This PR is mainly about exposing the python bindings for`
linalg::isaContractionOpInterface` and` linalg::inferContractionDims`.

---------

Signed-off-by: Bangtian Liu <[email protected]>

Author: bangtianliu

mlir/include/mlir-c/Dialect/Linalg.h

@@ -22,6 +22,18 @@ extern "C" {
 MLIR_CAPI_EXPORTED void
 mlirLinalgFillBuiltinNamedOpRegion(MlirOperation mlirOp);
 
+MLIR_CAPI_EXPORTED bool mlirLinalgIsContractionOp(MlirOperation op);
+
+struct MlirLinalgContractionDimensions {
+  MlirAttribute batch;
+  MlirAttribute m;
+  MlirAttribute n;
+  MlirAttribute k;
+};
+
+MLIR_CAPI_EXPORTED MlirLinalgContractionDimensions
+mlirLinalgInferContractionDimensions(MlirOperation op);
+
 MLIR_DECLARE_CAPI_DIALECT_REGISTRATION(Linalg, linalg);
 
 #ifdef __cplusplus

mlir/lib/Bindings/Python/DialectLinalg.cpp

@@ -8,10 +8,25 @@
 
 #include "mlir-c/Dialect/Linalg.h"
 #include "mlir-c/IR.h"
-#include "mlir/Bindings/Python/NanobindAdaptors.h"
 #include "mlir/Bindings/Python/Nanobind.h"
+#include "mlir/Bindings/Python/NanobindAdaptors.h"
 
 namespace nb = nanobind;
+using namespace mlir::python::nanobind_adaptors;
+
+static std::optional<MlirLinalgContractionDimensions>
+InferContractionDimensions(MlirOperation op) {
+  MlirLinalgContractionDimensions dims =
+      mlirLinalgInferContractionDimensions(op);
+
+  // Detect "empty" result. This occurs when `op` is not a contraction op,
+  // or when `linalg::inferContractionDims` fails.
+  if (mlirAttributeIsNull(dims.batch) && mlirAttributeIsNull(dims.m) &&
+      mlirAttributeIsNull(dims.n) && mlirAttributeIsNull(dims.k)) {
+    return std::nullopt;
+  }
+  return dims;
+}
 
 static void populateDialectLinalgSubmodule(nb::module_ m) {
   m.def(
@@ -20,6 +35,30 @@ static void populateDialectLinalgSubmodule(nb::module_ m) {
       nb::arg("op"),
       "Fill the region for `op`, which is assumed to be a builtin named Linalg "
       "op.");
+
+  m.def("isa_contraction_op", &mlirLinalgIsContractionOp,
+        "Checks if the given operation is a Linalg contraction operation.",
+        nb::arg("op"));
+
+  nb::class_<MlirLinalgContractionDimensions>(m, "ContractionDimensions")
+      .def_prop_ro("batch",
+                   [](const MlirLinalgContractionDimensions &self) {
+                     return self.batch;
+                   })
+      .def_prop_ro(
+          "m",
+          [](const MlirLinalgContractionDimensions &self) { return self.m; })
+      .def_prop_ro(
+          "n",
+          [](const MlirLinalgContractionDimensions &self) { return self.n; })
+      .def_prop_ro("k", [](const MlirLinalgContractionDimensions &self) {
+        return self.k;
+      });
+
+  m.def("infer_contraction_dimensions", &InferContractionDimensions,
+        "Infers contraction dimensions (batch/m/n/k) for a Linalg contraction "
+        "op.",
+        nb::arg("op"));
 }
 
 NB_MODULE(_mlirDialectsLinalg, m) {

mlir/lib/CAPI/Dialect/Linalg.cpp

@@ -41,4 +41,38 @@ void mlirLinalgFillBuiltinNamedOpRegion(MlirOperation mlirOp) {
   fun(b, *body, op->getAttrs());
 }
 
+MLIR_CAPI_EXPORTED bool mlirLinalgIsContractionOp(MlirOperation op) {
+  auto linalgOp = llvm::dyn_cast<mlir::linalg::LinalgOp>(unwrap(op));
+  // isaContractionOpInterface handles null linalgOp internally.
+  return linalg::isaContractionOpInterface(linalgOp);
+}
+
+MLIR_CAPI_EXPORTED MlirLinalgContractionDimensions
+mlirLinalgInferContractionDimensions(MlirOperation op) {
+  MlirLinalgContractionDimensions result{};
+  auto linalgOp = dyn_cast<linalg::LinalgOp>(unwrap(op));
+  if (!linalgOp)
+    return result;
+
+  FailureOr<linalg::ContractionDimensions> maybeDims =
+      linalg::inferContractionDims(linalgOp);
+  if (failed(maybeDims))
+    return result;
+
+  linalg::ContractionDimensions contractionDims = *maybeDims;
+  MLIRContext *ctx = linalgOp.getContext();
+
+  auto toAttr = [&ctx](const SmallVector<unsigned, 2> &vals) -> MlirAttribute {
+    return wrap(
+        DenseI32ArrayAttr::get(ctx, llvm::to_vector_of<int32_t, 2>(vals)));
+  };
+
+  result.batch = toAttr(contractionDims.batch);
+  result.m = toAttr(contractionDims.m);
+  result.n = toAttr(contractionDims.n);
+  result.k = toAttr(contractionDims.k);
+
+  return result;
+}
+
 MLIR_DEFINE_CAPI_DIALECT_REGISTRATION(Linalg, linalg, LinalgDialect)