[ET-VK] Store unique ptr to StagingBuffer and SymInt in Value instead of inlined object, to reduce Value struct size from 80 to 32 bytes.

This diff aims to reduce the size of the `Value` struct from 80 bytes to 32 bytes by storing a unique pointer to `StagingBuffer` and `SymInt` instead of inlining the objects.

Differential Revision: [D66677759](https://our.internmc.facebook.com/intern/diff/D66677759/)

ghstack-source-id: 256135680
Pull Request resolved: #7152

Author: trivedivivek

backends/vulkan/runtime/graph/containers/Value.h

@@ -59,7 +59,7 @@ struct Value final {
     } u;
 
     std::unique_ptr<api::vTensor> as_tensor;
-    api::StagingBuffer as_staging;
+    std::unique_ptr<api::StagingBuffer> as_staging;
     TensorRef as_tensorref;
 
     std::vector<int64_t> as_int_list;
@@ -73,7 +73,7 @@ struct Value final {
 
     std::string as_string;
 
-    SymInt as_symint;
+    std::unique_ptr<SymInt> as_symint;
 
     Payload() : u() {}
     // NOLINTNEXTLINE
@@ -117,9 +117,7 @@ struct Value final {
       CASE_MOVE_TRIVIALLY_COPYABLE_TYPE(TypeTag::INT, as_int);
       CASE_MOVE_TRIVIALLY_COPYABLE_TYPE(TypeTag::DOUBLE, as_double);
       CASE_MOVE_TRIVIALLY_COPYABLE_TYPE(TypeTag::BOOL, as_bool);
-      // Tensor adjacent types
-      CASE_MOVE_MOVEABLE_TYPE(
-          TypeTag::STAGING, api::StagingBuffer, as_staging, StagingBuffer);
+      // Tensor adjacent type
       CASE_MOVE_MOVEABLE_TYPE(
           TypeTag::TENSORREF, TensorRef, as_tensorref, TensorRef);
       // Scalar lists
@@ -134,9 +132,10 @@ struct Value final {
           TypeTag::VALUELIST, std::vector<ValueRef>, as_value_list, vector);
       CASE_MOVE_MOVEABLE_TYPE(
           TypeTag::STRING, std::string, as_string, basic_string);
-      CASE_MOVE_MOVEABLE_TYPE(TypeTag::SYMINT, SymInt, as_symint, SymInt);
       // Tensor type
       CASE_MOVE_UNIQUE_PTR_TYPE(TypeTag::TENSOR, as_tensor);
+      CASE_MOVE_UNIQUE_PTR_TYPE(TypeTag::STAGING, as_staging);
+      CASE_MOVE_UNIQUE_PTR_TYPE(TypeTag::SYMINT, as_symint);
 
       case TypeTag::NONE:
         clearToNone();
@@ -163,9 +162,6 @@ struct Value final {
 
   ~Value() {
     switch (tag) {
-      case TypeTag::STAGING:
-        payload.as_staging.~StagingBuffer();
-        break;
       case TypeTag::TENSORREF:
         payload.as_tensorref.~TensorRef();
         break;
@@ -184,9 +180,6 @@ struct Value final {
       case TypeTag::STRING:
         payload.as_string.~basic_string();
         break;
-      case TypeTag::SYMINT:
-        payload.as_symint.~SymInt();
-        break;
       // Manually list out the types so that if a type here is added later and
       // not handled the compiler can catch it.
       case TypeTag::NONE:
@@ -197,6 +190,12 @@ struct Value final {
       case TypeTag::TENSOR:
         payload.as_tensor.reset();
         break;
+      case TypeTag::STAGING:
+        payload.as_staging.reset();
+        break;
+      case TypeTag::SYMINT:
+        payload.as_symint.reset();
+        break;
     }
   }
 
@@ -258,12 +257,6 @@ struct Value final {
     return payload.member_name;                             \
   }
 
-  SUPPORT_TRIVIALLY_MOVEABLE_TYPE(
-      api::StagingBuffer,
-      Staging,
-      TypeTag::STAGING,
-      as_staging);
-
   SUPPORT_TRIVIALLY_MOVEABLE_TYPE(
       TensorRef,
       TensorRef,
@@ -300,8 +293,6 @@ struct Value final {
       TypeTag::STRING,
       as_string);
 
-  SUPPORT_TRIVIALLY_MOVEABLE_TYPE(SymInt, SymInt, TypeTag::SYMINT, as_symint);
-
 #undef SUPPORT_TRIVIALLY_MOVEABLE_TYPE
 
 #define SUPPORT_UNIQUE_PTR_TYPE(type, type_name, type_tag, member_name) \
@@ -330,6 +321,14 @@ struct Value final {
 
   SUPPORT_UNIQUE_PTR_TYPE(api::vTensor, Tensor, TypeTag::TENSOR, as_tensor);
 
+  SUPPORT_UNIQUE_PTR_TYPE(
+      api::StagingBuffer,
+      Staging,
+      TypeTag::STAGING,
+      as_staging);
+
+  SUPPORT_UNIQUE_PTR_TYPE(SymInt, SymInt, TypeTag::SYMINT, as_symint);
+
 #undef SUPPORT_UNIQUE_PTR_TYPE
 
  private: