Move tensor layout into exir

TensorLayout is used by the data_serializer.py abstract class, which is part of //executorch/exir:lib

https://www.internalfb.com/code/fbsource/[721dbb621c0b8c460715e5c49bc9c12757e8ccc8]/fbcode/executorch/exir/_serialize/data_serializer.py?lines=6

Shouldn't add extension/flat_tensor:flat_tensor_schema as a dependency to executorch/exir:lib.

Note the C++ equivalent is in runtime/core, so I think this makes sense.

Differential Revision: [D83504588](https://our.internmc.facebook.com/intern/diff/D83504588/)

[ghstack-poisoned]

Author: lucylq

exir/TARGETS

@@ -79,6 +79,16 @@ runtime.python_library(
     ],
 )
 
+runtime.python_library(
+    name = "tensor_layout",
+    srcs = [
+        "tensor_layout.py",
+    ],
+    deps = [
+        ":scalar_type",
+    ]
+)
+
 runtime.python_library(
     name = "memory",
     srcs = [

exir/_serialize/TARGETS

@@ -65,5 +65,6 @@ runtime.python_library(
     deps = [
         "//executorch/exir:schema",
         "//executorch/exir:tensor",
+        "//executorch/exir:tensor_layout",
     ],
 )

exir/_serialize/_serialize.py

@@ -16,12 +16,12 @@
     DataEntry,
     DataPayload,
     DataSerializer,
-    TensorLayout,
 )
 
 from executorch.exir.capture._config import ExecutorchBackendConfig
 from executorch.exir.emit import EmitterOutput
 from executorch.exir.schema import Tensor, TensorDataLocation
+from executorch.exir.tensor_layout import TensorLayout
 
 
 def serialize_for_executorch(

exir/_serialize/data_serializer.py

@@ -3,7 +3,7 @@
 from typing import Dict, Optional, Sequence
 
 from executorch.exir._serialize._cord import Cord
-from executorch.extension.flat_tensor.serialize.flat_tensor_schema import TensorLayout
+from executorch.exir.tensor_layout import TensorLayout
 
 
 @dataclass

exir/tensor_layout.py

@@ -0,0 +1,21 @@
+# 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.
+
+# pyre-unsafe
+
+from dataclasses import dataclass
+from typing import List
+
+from executorch.exir.scalar_type import ScalarType
+
+
+# Note: keep this in sync with the TensorLayout definition in
+# executorch/extension/flat_tensor/serialize/flat_tensor.fbs
+@dataclass
+class TensorLayout:
+    scalar_type: ScalarType
+    sizes: List[int]
+    dim_order: List[int]

extension/flat_tensor/serialize/TARGETS

@@ -13,6 +13,9 @@ runtime.python_library(
     visibility = [
         "//executorch/...",
     ],
+    deps = [
+        "//executorch/exir:tensor_layout",
+    ]
 )
 
 runtime.python_library(

extension/flat_tensor/serialize/flat_tensor.fbs

@@ -7,6 +7,8 @@ namespace flat_tensor_flatbuffer;
 file_identifier "FT01";
 file_extension "ptd";
 
+// Note: keep this in sync with the python definition in
+// executorch/exir/tensor_layout.py
 table TensorLayout {
   scalar_type: executorch_flatbuffer.ScalarType;
 

extension/flat_tensor/serialize/flat_tensor_schema.py

@@ -9,18 +9,11 @@
 from dataclasses import dataclass
 from typing import List, Optional
 
-from executorch.exir.scalar_type import ScalarType
+from executorch.exir.tensor_layout import TensorLayout
 
 # Note: check executorch/extension/data_format/flat_tensor.fbs for explanations of these fields.
 
 
-@dataclass
-class TensorLayout:
-    scalar_type: ScalarType
-    sizes: List[int]
-    dim_order: List[int]
-
-
 @dataclass
 class DataSegment:
     offset: int

extension/flat_tensor/test/test_serialize.py

@@ -22,7 +22,7 @@
 from executorch.exir._serialize.padding import aligned_size
 
 from executorch.exir.schema import ScalarType
-from executorch.extension.flat_tensor.serialize.flat_tensor_schema import TensorLayout
+from executorch.exir.tensor_layout import TensorLayout
 
 from executorch.extension.flat_tensor.serialize.serialize import (
     _deserialize_to_flat_tensor,