[mlir][linalg] Create a dedicated target for LinalgRelayoutInterface (llvm#128485)

Creates an interface target for `LinalgRelayoutInterface`. This is
primarily to reduce the dependency of `Tensor` on `Linalg` to the
required minimum. For context and rationale, see:
  * llvm#127668

Note, I also took the liberty of renaming `LinalgRelayoutInterface` as
`RelayoutOpInterface` (removed `Linalg`, added `Op`).

Author: banach-space

mlir/include/mlir/Dialect/Linalg/IR/CMakeLists.txt

@@ -25,6 +25,22 @@ function(add_linalg_ods_yaml_gen yaml_ast_file output_file)
   set(LLVM_TARGET_DEPENDS ${LLVM_TARGET_DEPENDS} PARENT_SCOPE)
 endfunction()
 
+# NOTE: `add_mlir_interface(interface)` adds `interface` as a dependency of
+# mlir-generic-headers, i.e.:
+#   * mlir-generic-headers -> interface
+# In addition, we have an existing MLIR-wide dependency of:
+#   * mlir-headers -> mlir-generic-headers.
+# Now, observe that:
+#   1. The targets below define _new_ dependencies for mlir-headers.
+#   2. Before the new targets are defined, `add_linalg_ods_yaml_gen` updates
+#     LLVM_TARGET_DEPENDS.
+#   3. All tablegen targets pick-up LLVM_TARGET_DEPENDS.
+# In order to avoid cyclic dependencies, we need to invoke
+# `add_mlir_interface` (and update `mlir-generic-headers`) _before_
+# LLVM_TARGET_DEPENDS is updated and new dependencies for `mlir-headers` are
+# defined + added.
+add_mlir_interface(RelayoutOpInterface)
+
 # NOTE: LLVM_TARGET_DEPENDS gets picked up by tablegen targets to add file
 # level dependencies. This is gross but CMake requires depending on both
 # targets and generated files, and it must be done when the custom target is
@@ -77,3 +93,4 @@ mlir_tablegen(LinalgInterfaces.h.inc -gen-op-interface-decls)
 mlir_tablegen(LinalgInterfaces.cpp.inc -gen-op-interface-defs)
 add_public_tablegen_target(MLIRLinalgInterfacesIncGen)
 add_dependencies(mlir-headers MLIRLinalgInterfacesIncGen)
+

mlir/include/mlir/Dialect/Linalg/IR/LinalgInterfaces.h

@@ -221,4 +221,7 @@ LogicalResult verifyStructuredOpInterface(Operation *op);
 /// Include the generated interface declarations.
 #include "mlir/Dialect/Linalg/IR/LinalgInterfaces.h.inc"
 
+/// Include the generated relayout interface declarations.
+#include "mlir/Dialect/Linalg/IR/RelayoutOpInterface.h.inc"
+
 #endif // MLIR_DIALECT_LINALG_IR_LINALGINTERFACES_H_

mlir/include/mlir/Dialect/Linalg/IR/LinalgInterfaces.td

@@ -178,16 +178,6 @@ def LinalgConvolutionOpInterface : OpInterface<"ConvolutionOpInterface"> {
   ];
 }
 
-def LinalgRelayoutOpInterface : OpInterface<"RelayoutOpInterface"> {
-  let description = [{
-    A Linalg relayout-op is either linalg.pack or linalg.unpack.
-
-    While we could extend this interface with methods from Linalg_RelayoutOp,
-    this is currently not needed and left as a TODO.
-  }];
-  let cppNamespace = "::mlir::linalg";
-}
-
 def LinalgFillOpInterface : OpInterface<"FillOpInterface"> {
   let description = [{
     A fill operation is defined in general terms:

mlir/include/mlir/Dialect/Linalg/IR/LinalgRelayoutOps.td

@@ -23,6 +23,7 @@ include "mlir/Interfaces/DestinationStyleOpInterface.td"
 include "mlir/Interfaces/SideEffectInterfaces.td"
 include "mlir/Interfaces/InferTypeOpInterface.td"
 include "mlir/Dialect/Linalg/IR/LinalgInterfaces.td"
+include "mlir/Dialect/Linalg/IR/RelayoutOpInterface.td"
 include "mlir/IR/OpAsmInterface.td"
 
 //===----------------------------------------------------------------------===//

mlir/include/mlir/Dialect/Linalg/IR/RelayoutOpInterface.h

@@ -0,0 +1,18 @@
+//===- RelayoutOpInterface.h - Relayout op interface ----------------------===//
+//
+// 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 implements the operation interface for relayout ops.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_DIALECT_RELAYOUTOPINTERFACE_H_
+#define MLIR_DIALECT_RELAYOUTOPINTERFACE_H_
+
+#include "mlir/Dialect/Linalg/IR/RelayoutOpInterface.h.inc"
+
+#endif // MLIR_DIALECT_RELAYOUTOPINTERFACE_H_

mlir/include/mlir/Dialect/Linalg/IR/RelayoutOpInterface.td

@@ -0,0 +1,25 @@
+//===- RelayoutOpInterface.td ----- Intrerface Declaration -*- tablegen -*-===//
+//
+// 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 LINALG_IR_RELAYOUTOPINTERFACE
+#define LINALG_IR_RELAYOUTOPINTERFACE
+
+include "mlir/Interfaces/DestinationStyleOpInterface.td"
+include "mlir/IR/OpBase.td"
+
+def LinalgRelayoutOpInterface : OpInterface<"RelayoutOpInterface"> {
+  let description = [{
+    A Linalg relayout-op is either linalg.pack or linalg.unpack.
+
+    While we could extend this interface with methods from Linalg_RelayoutOp,
+    this is currently not needed and left as a TODO.
+  }];
+  let cppNamespace = "::mlir::linalg";
+}
+
+#endif // LINALG_IR_RELAYOUTOPINTERFACE

mlir/lib/Dialect/Tensor/IR/TensorOps.cpp

@@ -10,7 +10,7 @@
 #include "mlir/Dialect/Arith/IR/Arith.h"
 #include "mlir/Dialect/Arith/Utils/Utils.h"
 #include "mlir/Dialect/Complex/IR/Complex.h"
-#include "mlir/Dialect/Linalg/IR/LinalgInterfaces.h"
+#include "mlir/Dialect/Linalg/IR/RelayoutOpInterface.h"
 #include "mlir/Dialect/Tensor/IR/Tensor.h"
 #include "mlir/Dialect/Utils/IndexingUtils.h"
 #include "mlir/Dialect/Utils/ReshapeOpsUtils.h"