Update on "[ET-VK] Replace Uniform buffers with push constants for copy op"

This diff replaces uniform buffers with push constants for copy op in the Vulkan backend of Executorch. The changes include updating the GLSL code to use push constants instead of uniform buffers and updating the C++ code to pass the sizes as push constants to the shader.

Differential Revision: [D66890851](https://our.internmc.facebook.com/intern/diff/D66890851/)

[ghstack-poisoned]

Author: trivedivivek

backends/vulkan/runtime/graph/ops/DispatchNode.h

@@ -32,7 +32,7 @@ class PushConstantDataInfo {
     };
     struct {
       uint8_t data[16];
-      uint32_t dataSize{};
+      uint32_t dataSize;
     };
   };
 
@@ -46,12 +46,15 @@ class PushConstantDataInfo {
     payload_.attr = attr;
   }
 
-  explicit PushConstantDataInfo(const void* data, uint32_t dataLen)
+  explicit PushConstantDataInfo(
+      const void* data,
+      uint32_t dataLen,
+      uint32_t pushConstantLen = 0)
       : tensorUniformData(nullptr) {
     VK_CHECK_COND(
         dataLen <= 16, "Single push constant data size must be <= 16 bytes");
-    payload_.dataSize = dataLen;
-    memcpy(payload_.data, data, payload_.dataSize);
+    payload_.dataSize = pushConstantLen ? pushConstantLen : dataLen;
+    memcpy(payload_.data, data, dataLen);
   }
 
   /*

backends/vulkan/runtime/graph/ops/impl/Copy.cpp

@@ -52,9 +52,9 @@ void add_copy_offset_node(
       nullptr,
       {},
       {
-          PushConstantDataInfo(&range, sizeof(range)),
-          PushConstantDataInfo(&src_offset, sizeof(src_offset)),
-          PushConstantDataInfo(&dst_offset, sizeof(dst_offset)),
+          PushConstantDataInfo(&range, sizeof(range), sizeof(utils::ivec4)),
+          PushConstantDataInfo(&src_offset, sizeof(src_offset), sizeof(utils::ivec4)),
+          PushConstantDataInfo(&dst_offset, sizeof(dst_offset), sizeof(utils::ivec4)),
       }));
 }