[ET][Metal] Update aoti_common with additional AOTI functions needed by Metal backend

backends/aoti/aoti_model_container.cpp

@@ -25,6 +25,12 @@ AOTInductorModelContainerGetNumOutputsFunc
     AOTInductorModelContainerGetNumOutputs = nullptr;
 AOTInductorModelContainerRunFunc AOTInductorModelContainerRun = nullptr;
 
+// Global function pointers needed by Metal backend
+AOTInductorModelContainerGetInputNameFunc
+    AOTInductorModelContainerGetInputName = nullptr;
+AOTInductorModelContainerGetNumConstantsFunc
+    AOTInductorModelContainerGetNumConstants = nullptr;
+
 } // extern "C"
 
 } // namespace aoti

backends/aoti/aoti_model_container.h

@@ -70,6 +70,22 @@ extern AOTInductorModelContainerGetNumOutputsFunc
     AOTInductorModelContainerGetNumOutputs;
 extern AOTInductorModelContainerRunFunc AOTInductorModelContainerRun;
 
+// Function pointer types needed by Metal backend
+using AOTInductorModelContainerGetInputNameFunc = AOTIRuntimeError (*)(
+    AOTInductorModelContainerHandle container_handle,
+    size_t input_idx,
+    const char** input_name);
+
+using AOTInductorModelContainerGetNumConstantsFunc = AOTIRuntimeError (*)(
+    AOTInductorModelContainerHandle container_handle,
+    size_t* num_constants);
+
+// Global function pointers needed by Metal backend
+extern AOTInductorModelContainerGetInputNameFunc
+    AOTInductorModelContainerGetInputName;
+extern AOTInductorModelContainerGetNumConstantsFunc
+    AOTInductorModelContainerGetNumConstants;
+
 } // extern "C"
 
 // AOTI Delegate Handle structure

backends/aoti/common_shims.cpp

@@ -145,6 +145,11 @@ void cleanup_tensor_metadata() {
   internal::tensor_to_strides.clear();
 }
 
+// Needed by Metal backend
+size_t aoti_torch_dtype_element_size(int32_t dtype) {
+  return dtype_to_element_size(dtype);
+}
+
 } // extern "C"
 
 } // namespace aoti

backends/aoti/common_shims.h

@@ -68,6 +68,9 @@ void aoti_torch_grad_mode_set_enabled(bool enabled);
 // Cleanup functions for clearing global state
 void cleanup_tensor_metadata();
 
+// Needed by Metal backend
+size_t aoti_torch_dtype_element_size(int32_t dtype);
+
 } // extern "C"
 
 } // namespace aoti