Expose portable ops as utils (add/stack)

kernels/portable/cpu/op_add.cpp

@@ -15,6 +15,7 @@
 namespace torch {
 namespace executor {
 namespace native {
+namespace impl {
 
 Tensor& add_out(
     KernelRuntimeContext& ctx,
@@ -151,6 +152,47 @@ Tensor& add_scalar_out(
   return out;
 }
 
+} // namespace impl
+
+Tensor& add_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& a,
+    const Tensor& b,
+    const Scalar& alpha,
+    Tensor& out) {
+  return impl::add_out(ctx, a, b, alpha, out);
+}
+
+Tensor& add_scalar_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& a,
+    const Scalar& b,
+    const Scalar& alpha,
+    Tensor& out) {
+  return impl::add_scalar_out(ctx, a, b, alpha, out);
+}
+
+namespace utils {
+
+Tensor& add_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& a,
+    const Tensor& b,
+    const Scalar& alpha,
+    Tensor& out) {
+  return impl::add_out(ctx, a, b, alpha, out);
+}
+
+Tensor& add_scalar_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& a,
+    const Scalar& b,
+    const Scalar& alpha,
+    Tensor& out) {
+  return impl::add_scalar_out(ctx, a, b, alpha, out);
+}
+
+} // namespace utils
 } // namespace native
 } // namespace executor
 } // namespace torch

kernels/portable/cpu/op_add.h

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <executorch/runtime/kernel/kernel_includes.h>
+
+#pragma once
+
+namespace torch {
+namespace executor {
+namespace native {
+namespace utils {
+
+Tensor& add_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& a,
+    const Tensor& b,
+    const Scalar& alpha,
+    Tensor& out);
+
+Tensor& add_scalar_out(
+    KernelRuntimeContext& ctx,
+    const Tensor& a,
+    const Scalar& b,
+    const Scalar& alpha,
+    Tensor& out);
+
+} // namespace utils
+} // namespace native
+} // namespace executor
+} // namespace torch

kernels/portable/cpu/op_stack.cpp

@@ -14,6 +14,7 @@
 namespace torch {
 namespace executor {
 namespace native {
+namespace impl {
 
 using Tensor = executorch::aten::Tensor;
 
@@ -76,6 +77,27 @@ Tensor& stack_out(
   return out;
 }
 
+} // namespace impl
+
+Tensor& stack_out(
+    KernelRuntimeContext& ctx,
+    executorch::aten::ArrayRef<Tensor> tensors,
+    int64_t dim,
+    Tensor& out) {
+  return impl::stack_out(ctx, tensors, dim, out);
+}
+
+namespace utils {
+
+Tensor& stack_out(
+    KernelRuntimeContext& ctx,
+    executorch::aten::ArrayRef<Tensor> tensors,
+    int64_t dim,
+    Tensor& out) {
+  return impl::stack_out(ctx, tensors, dim, out);
+}
+
+} // namespace utils
 } // namespace native
 } // namespace executor
 } // namespace torch

kernels/portable/cpu/op_stack.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <executorch/runtime/kernel/kernel_includes.h>
+
+#pragma once
+
+namespace torch {
+namespace executor {
+namespace native {
+namespace utils {
+
+Tensor& stack_out(
+    KernelRuntimeContext& ctx,
+    executorch::aten::ArrayRef<Tensor> tensors,
+    int64_t dim,
+    Tensor& out);
+
+} // namespace utils
+} // namespace native
+} // namespace executor
+} // namespace torch

shim_et/xplat/executorch/kernels/portable/op_registration_util.bzl

@@ -5,7 +5,7 @@ def get_compiler_optimization_flags():
     # App size regressons requires this to be baktraced until I have a better solution
     return []
 
-def op_target(name, deps = [], android_deps = [], _allow_third_party_deps = False, _aten_mode_deps = []):
+def op_target(name, deps = [], android_deps = [], _allow_third_party_deps = False, _aten_mode_deps = [], exposed_as_util = False):
     """Registers an implementation of an operator overload group.
 
     An operator overload group is a set of operator overloads with a common
@@ -45,6 +45,8 @@ def op_target(name, deps = [], android_deps = [], _allow_third_party_deps = Fals
             from third-party optimization libraries.
         _aten_mode_deps: List of deps to add to the cxx_library() when building
             for ATen mode.
+        exposed_as_util: If True, this op has a utils namespace that should be exposed
+            as a separate library target for reuse by other operators.
     """
 
     # Note that this doesn't actually define the target, but helps register
@@ -55,6 +57,7 @@ def op_target(name, deps = [], android_deps = [], _allow_third_party_deps = Fals
         "name": name,
         "_allow_third_party_deps": _allow_third_party_deps,
         "_aten_mode_deps": _aten_mode_deps,
+        "exposed_as_util": exposed_as_util,
     }
 
 def _enforce_deps(deps, name, allow_third_party_deps):
@@ -154,7 +157,7 @@ def define_op_library(name, deps, android_deps, aten_target, _allow_third_party_
         link_whole = True,
     )
 
-def define_op_target(name, deps, android_deps, is_aten_op, is_et_op = True, _allow_third_party_deps = False, _aten_mode_deps = []):
+def define_op_target(name, deps, android_deps, is_aten_op, is_et_op = True, _allow_third_party_deps = False, _aten_mode_deps = [], exposed_as_util = False):
     """Possibly defines cxx_library targets for the named operator group.
 
     Args:
@@ -166,8 +169,37 @@ def define_op_target(name, deps, android_deps, is_aten_op, is_et_op = True, _all
         _allow_third_party_deps: If True, the op is allowed to depend on
             third-party deps outside of //executorch. Should only be used by
             targets under //executorch/kernels/optimized.
+        exposed_as_util: If True, this op has a utils namespace that should be exposed
+            as a separate library target for reuse by other operators.
     """
 
+    # If this op has utils, create a separate utils library target
+    if exposed_as_util:
+        utils_name = name + "_util"
+        runtime.cxx_library(
+            name = utils_name,
+            srcs = ["{}.cpp".format(name)],
+            exported_headers = ["{}.h".format(name)],
+            visibility = [
+                "//executorch/kernels/portable/...",
+                "//executorch/kernels/quantized/...",
+                "//executorch/kernels/optimized/...",
+                "//executorch/kernels/test/...",
+                "@EXECUTORCH_CLIENTS",
+            ],
+            fbandroid_platform_deps = android_deps,
+            compiler_flags = select({
+                    "DEFAULT": ["-Wno-missing-prototypes"],
+                    "ovr_config//os:windows": [],
+                }) + (
+                ["-fvisibility=hidden"] if is_xplat() else []
+            ) + get_compiler_optimization_flags(),
+            deps = [
+                "//executorch/runtime/kernel:kernel_includes",
+            ] + deps,
+            force_static = True,
+        )
+
     # If this is a custom op, define a target that builds it with at::Tensor
     # so that it can be imported into a host PyTorch environment for authoring.
     if not is_aten_op and True in get_aten_mode_options():
@@ -226,6 +258,7 @@ ATEN_OPS = (
             "//executorch/kernels/portable/cpu/util:kernel_ops_util",
             ":scalar_utils",
         ],
+        exposed_as_util = True,
     ),
     op_target(
         name = "op_addmm",
@@ -1194,6 +1227,7 @@ ATEN_OPS = (
         deps = [
             "//executorch/kernels/portable/cpu/util:copy_ops_util",
         ],
+        exposed_as_util = True,
     ),
     op_target(
         name = "op_sub",