[ET-VK] Deserialize VkGraph in ET-VK

Add logic to deserialize a VkGraph blob back python object. This allows us to get a implement debugging / visualization directly on the vulkan-exported program.  Still extra works need to be done: From the entire bundle, need to extract the specific vulkan delegate first.

Differential Revision: [D66443780](https://our.internmc.facebook.com/intern/diff/D66443780/)

[ghstack-poisoned]

Author: yipjustin

backends/vulkan/serialization/vulkan_graph_serialize.py

@@ -19,9 +19,9 @@
     VkBytes,
     VkGraph,
 )
-from executorch.exir._serialize._dataclass import _DataclassEncoder
+from executorch.exir._serialize._dataclass import _DataclassEncoder, _json_to_dataclass
 
-from executorch.exir._serialize._flatbuffer import _flatc_compile
+from executorch.exir._serialize._flatbuffer import _flatc_compile, _flatc_decompile
 
 
 def convert_to_flatbuffer(vk_graph: VkGraph) -> bytes:
@@ -40,6 +40,23 @@ def convert_to_flatbuffer(vk_graph: VkGraph) -> bytes:
             return output_file.read()
 
 
+def flatbuffer_to_vk_graph(flatbuffers: bytes) -> VkGraph:
+    with tempfile.TemporaryDirectory() as d:
+        schema_path = os.path.join(d, "schema.fbs")
+        with open(schema_path, "wb") as schema_file:
+            schema_file.write(pkg_resources.resource_string(__name__, "schema.fbs"))
+
+        bin_path = os.path.join(d, "schema.bin")
+        with open(bin_path, "wb") as bin_file:
+            bin_file.write(flatbuffers)
+
+        _flatc_decompile(d, schema_path, bin_path, ["--raw-binary"])
+
+        json_path = os.path.join(d, "schema.json")
+        with open(json_path, "rb") as output_file:
+            return _json_to_dataclass(json.load(output_file), VkGraph)
+
+
 @dataclass
 class VulkanDelegateHeader:
     # Defines the byte region that each component of the header corresponds to

backends/vulkan/test/test_serialization.py

@@ -11,9 +11,17 @@
 
 import torch
 
-from executorch.backends.vulkan.serialization.vulkan_graph_schema import VkGraph
+from executorch.backends.vulkan.serialization.vulkan_graph_schema import (
+    IntList,
+    OperatorCall,
+    String,
+    VkGraph,
+    VkValue,
+)
 
 from executorch.backends.vulkan.serialization.vulkan_graph_serialize import (
+    convert_to_flatbuffer,
+    flatbuffer_to_vk_graph,
     serialize_vulkan_graph,
     VulkanDelegateHeader,
 )
@@ -93,3 +101,33 @@ def test_serialize_vulkan_binary(self):
 
             tensor_bytes = bytes(array)
             self.assertEqual(constant_data_bytes, tensor_bytes)
+
+    def test_serialize_deserialize_vkgraph(self):
+        in_vk_graph = VkGraph(
+            version="1",
+            chain=[
+                OperatorCall(node_id=1, name="foo", args=[1, 2, 3]),
+                OperatorCall(node_id=2, name="bar", args=[]),
+            ],
+            values=[
+                VkValue(
+                    value=String(
+                        string_val="abc",
+                    ),
+                ),
+                VkValue(
+                    value=IntList(
+                        items=[-1, -4, 2],
+                    ),
+                ),
+            ],
+            input_ids=[],
+            output_ids=[],
+            constants=[],
+            shaders=[],
+        )
+
+        bs = convert_to_flatbuffer(in_vk_graph)
+        out_vk_graph = flatbuffer_to_vk_graph(bs)
+
+        self.assertEqual(in_vk_graph, out_vk_graph)