second temp commit: i will soft-reset and recommit after next changes

src/PIM/Dialect/Spatial/SpatialLayoutInterface.td

@@ -0,0 +1,24 @@
+#ifndef SPATIAL_LAYOUT_INTERFACE_TD
+#define SPATIAL_LAYOUT_INTERFACE_TD
+
+include "mlir/IR/OpBase.td"
+
+def SpatialLayoutCapabilityInterface : OpInterface<"SpatialLayoutCapabilityInterface"> {
+  let description = [{
+    Contract implemented by logical Spatial planning operations that expose
+    their legal physical layout alternatives to the Spatial planner.
+  }];
+
+  let methods = [
+    InterfaceMethod<
+      "Return legal physical layout alternatives for this operation and its current operand layouts.",
+      "::llvm::SmallVector<::onnx_mlir::spatial::LayoutAlternative>",
+      "getLayoutAlternatives",
+      (ins "const ::onnx_mlir::spatial::SpatialTargetInfo &":$target,
+           "::llvm::ArrayRef<::onnx_mlir::spatial::PhysicalLayout>":$operandLayouts)>
+  ];
+
+  let cppNamespace = "::onnx_mlir::spatial";
+}
+
+#endif