[Metal] Update aoti_common with additional AOTI functions needed by Metal backend (#15003)

Author: manuelcandales

backends/aoti/aoti_model_container.cpp

@@ -25,6 +25,13 @@ AOTInductorModelContainerGetNumOutputsFunc
     AOTInductorModelContainerGetNumOutputs = nullptr;
 AOTInductorModelContainerRunFunc AOTInductorModelContainerRun = nullptr;
 
+// Additional global function pointers for AOT Inductor model container
+// operations needed by Metal backend
+AOTInductorModelContainerGetInputNameFunc
+    AOTInductorModelContainerGetInputName = nullptr;
+AOTInductorModelContainerGetNumConstantsFunc
+    AOTInductorModelContainerGetNumConstants = nullptr;
+
 } // extern "C"
 
 } // namespace aoti

backends/aoti/aoti_model_container.h

@@ -70,6 +70,26 @@ extern AOTInductorModelContainerGetNumOutputsFunc
     AOTInductorModelContainerGetNumOutputs;
 extern AOTInductorModelContainerRunFunc AOTInductorModelContainerRun;
 
+// Retrieves the name of an input tensor by index from the AOTI model container.
+// Needed by Metal backend
+using AOTInductorModelContainerGetInputNameFunc = AOTIRuntimeError (*)(
+    AOTInductorModelContainerHandle container_handle,
+    size_t input_idx,
+    const char** input_name);
+
+// Retrieves the number of constants from the AOTI model container.
+// Needed by Metal backend
+using AOTInductorModelContainerGetNumConstantsFunc = AOTIRuntimeError (*)(
+    AOTInductorModelContainerHandle container_handle,
+    size_t* num_constants);
+
+// Global function pointers (will be loaded dynamically).
+// Needed by Metal backend
+extern AOTInductorModelContainerGetInputNameFunc
+    AOTInductorModelContainerGetInputName;
+extern AOTInductorModelContainerGetNumConstantsFunc
+    AOTInductorModelContainerGetNumConstants;
+
 } // extern "C"
 
 // AOTI Delegate Handle structure

backends/aoti/common_shims.cpp

@@ -176,6 +176,12 @@ int32_t aoti_torch_dtype_int64() {
   return 4; // PyTorch's int64 dtype code
 }
 
+// Dtype utility function needed by Metal backend.
+// Returns the size of the dtype in bytes.
+size_t aoti_torch_dtype_element_size(int32_t dtype) {
+  return dtype_to_element_size(dtype);
+}
+
 // Cleanup functions
 void cleanup_tensor_metadata() {
   internal::tensor_to_sizes.clear();

backends/aoti/common_shims.h

@@ -61,6 +61,9 @@ int32_t aoti_torch_dtype_float32();
 int32_t aoti_torch_dtype_bfloat16();
 int32_t aoti_torch_dtype_int64();
 
+// Dtype utility function needed by Metal backend
+size_t aoti_torch_dtype_element_size(int32_t dtype);
+
 // Autograd mode functions
 int32_t aoti_torch_grad_mode_is_enabled();
 void aoti_torch_grad_mode_set_enabled(bool enabled);