Add aoti_torch_item_bool and aoti_torch_assign_tensors_out shims (pytorch#16345)

Add two new shim implementations for the CUDA AOTI backend:

1. aoti_torch_item_bool: Extracts a boolean value from a 0D boolean
tensor.
Handles both CPU and CUDA tensors by using cudaPointerGetAttributes to
   determine the memory location and copying from device if needed.

2. aoti_torch_assign_tensors_out: Creates a new tensor view that shares
the
same underlying data as the source tensor. The new tensor has the same
   shape, strides, and dtype as the source.

Also adds:
- Declaration of aoti_torch_dtype_bool() in common_shims.h
- Unit tests for both new functions
- Update CMakeLists.txt with new test targets
- Update targets.bzl with new test targets

Author: larryliu0820

backends/aoti/common_shims.h

@@ -64,6 +64,7 @@ AOTI_SHIM_EXPORT int32_t aoti_torch_device_type_cpu();
 AOTI_SHIM_EXPORT int32_t aoti_torch_layout_strided();
 AOTI_SHIM_EXPORT int32_t aoti_torch_dtype_float32();
 AOTI_SHIM_EXPORT int32_t aoti_torch_dtype_bfloat16();
+AOTI_SHIM_EXPORT int32_t aoti_torch_dtype_bool();
 AOTI_SHIM_EXPORT int32_t aoti_torch_dtype_int8();
 AOTI_SHIM_EXPORT int32_t aoti_torch_dtype_int16();
 AOTI_SHIM_EXPORT int32_t aoti_torch_dtype_int32();

backends/cuda/runtime/shims/memory.cpp

@@ -24,6 +24,7 @@ namespace executorch::backends::cuda {
 
 using executorch::aten::SizesType;
 using executorch::aten::StridesType;
+using executorch::backends::aoti::aoti_torch_dtype_bool;
 using executorch::backends::aoti::aoti_torch_get_device_index;
 using executorch::backends::aoti::aoti_torch_get_dtype;
 using executorch::backends::aoti::aoti_torch_get_sizes;
@@ -800,6 +801,126 @@ AOTITorchError aoti_torch_new_tensor_handle(
 
   return Error::Ok;
 }
+
+AOTITorchError aoti_torch_item_bool(Tensor* tensor, bool* ret_value) {
+  // Validate input parameters
+  ET_CHECK_OR_RETURN_ERROR(
+      tensor != nullptr,
+      InvalidArgument,
+      "aoti_torch_item_bool failed: tensor is null");
+
+  ET_CHECK_OR_RETURN_ERROR(
+      ret_value != nullptr,
+      InvalidArgument,
+      "aoti_torch_item_bool failed: ret_value is null");
+
+  // Validate that tensor dtype is bool
+  int32_t dtype;
+  ET_CHECK_OK_OR_RETURN_ERROR(aoti_torch_get_dtype(tensor, &dtype));
+
+  ET_CHECK_OR_RETURN_ERROR(
+      dtype == aoti_torch_dtype_bool(),
+      InvalidArgument,
+      "aoti_torch_item_bool failed: tensor dtype is not bool (got %d)",
+      dtype);
+
+  // Get the data pointer
+  const void* data_ptr = tensor->const_data_ptr();
+  ET_CHECK_OR_RETURN_ERROR(
+      data_ptr != nullptr,
+      InvalidArgument,
+      "aoti_torch_item_bool failed: tensor data pointer is null");
+
+  // Check if tensor is on CUDA or CPU
+  cudaPointerAttributes attributes{};
+  ET_CUDA_CHECK_OR_RETURN_ERROR(
+      cudaPointerGetAttributes(&attributes, data_ptr));
+
+  if (attributes.type == cudaMemoryTypeDevice) {
+    // CUDA memory case: copy from device to host
+    bool device_value;
+    ET_CUDA_CHECK_OR_RETURN_ERROR(cudaMemcpy(
+        &device_value, data_ptr, sizeof(bool), cudaMemcpyDeviceToHost));
+    *ret_value = device_value;
+  } else {
+    // CPU memory case: direct access
+    const bool* bool_ptr = static_cast<const bool*>(data_ptr);
+    *ret_value = *bool_ptr;
+  }
+
+  return Error::Ok;
+}
+
+AOTITorchError aoti_torch_assign_tensors_out(Tensor* src, Tensor** ret_dst) {
+  // Validate input parameters
+  ET_CHECK_OR_RETURN_ERROR(
+      src != nullptr,
+      InvalidArgument,
+      "aoti_torch_assign_tensors_out failed: src is null");
+
+  ET_CHECK_OR_RETURN_ERROR(
+      ret_dst != nullptr,
+      InvalidArgument,
+      "aoti_torch_assign_tensors_out failed: ret_dst is null");
+
+  // Get the data pointer from the source tensor
+  void* data_ptr = src->mutable_data_ptr();
+  ET_CHECK_OR_RETURN_ERROR(
+      data_ptr != nullptr,
+      InvalidArgument,
+      "Source tensor has null data pointer");
+
+  // Check if the given memory is in the map, if not return error
+  auto memory_it = memory_to_n_tensor.find(data_ptr);
+  ET_CHECK_OR_RETURN_ERROR(
+      memory_it != memory_to_n_tensor.end(),
+      InvalidArgument,
+      "Memory address %p is not being tracked by reference counting system",
+      data_ptr);
+
+  // Get dtype from source tensor
+  int32_t dtype = 0;
+  ET_CHECK_OK_OR_RETURN_ERROR(aoti_torch_get_dtype(src, &dtype));
+
+  // Get sizes and strides from source tensor
+  int64_t* sizes_ptr;
+  int64_t* strides_ptr;
+  ET_CHECK_OK_OR_RETURN_ERROR(aoti_torch_get_sizes(src, &sizes_ptr));
+  ET_CHECK_OK_OR_RETURN_ERROR(aoti_torch_get_strides(src, &strides_ptr));
+
+  int64_t ndim = src->dim();
+
+  // Convert to vectors
+  std::vector<SizesType> sizes = convert_sizes_to_vector(ndim, sizes_ptr);
+  std::vector<StridesType> strides =
+      convert_strides_to_vector(ndim, sizes_ptr, strides_ptr);
+
+  // Create new tensor view that shares the same memory as source tensor
+  std::shared_ptr<Tensor> tensor = make_tensor(
+      sizes,
+      data_ptr, // Share the same memory from source tensor
+      {}, // dim_order (empty, will be auto-generated)
+      strides,
+      dtype_to_scalar_type(dtype));
+
+  ET_CHECK_OR_RETURN_ERROR(
+      tensor != nullptr,
+      InvalidArgument,
+      "Failed to create tensor view in aoti_torch_assign_tensors_out");
+
+  // Store the tensor so it doesn't get destroyed
+  tensors.insert(tensor);
+
+  *ret_dst = tensor.get();
+
+  // Increment the reference count for this memory address only if it is owned
+  // by tensor
+  memory_to_n_tensor[data_ptr] = memory_to_n_tensor[data_ptr] == NOT_OWN
+      ? NOT_OWN
+      : memory_to_n_tensor[data_ptr] + 1;
+
+  return Error::Ok;
+}
 } // extern "C"
 
 } // namespace executorch::backends::cuda

backends/cuda/runtime/shims/memory.h

@@ -161,9 +161,41 @@ aoti_torch_copy_(Tensor* self, Tensor* src, int32_t non_blocking);
  * @return Error::Ok on success, appropriate error code on failure:
  *         - Error::InvalidArgument: null pointers or invalid parameters
  */
-AOTITorchError aoti_torch_new_tensor_handle(
-    Tensor* orig_handle,
-    Tensor** new_handle);
+AOTI_SHIM_EXPORT AOTITorchError
+aoti_torch_new_tensor_handle(Tensor* orig_handle, Tensor** new_handle);
+
+/**
+ * Retrieves a boolean value from a 0D boolean tensor.
+ *
+ * This function extracts the scalar boolean value from a tensor that contains
+ * a single boolean element. The tensor can be on either CPU or CUDA device.
+ * For CUDA tensors, the value is copied from device to host memory.
+ *
+ * @param tensor Pointer to a 0D boolean tensor (must not be null)
+ * @param ret_value Output pointer to store the boolean value (must not be null)
+ *
+ * @return Error::Ok on success, appropriate error code on failure:
+ *         - Error::InvalidArgument: null pointers or tensor dtype is not bool
+ */
+AOTI_SHIM_EXPORT AOTITorchError
+aoti_torch_item_bool(Tensor* tensor, bool* ret_value);
+
+/**
+ * Creates a new tensor that shares the same underlying data as the source
+ * tensor.
+ *
+ * This function creates a new tensor view with the same shape, strides, and
+ * dtype as the source tensor, sharing the same underlying memory. The new
+ * tensor handle will be stored in ret_dst.
+ *
+ * @param src The source tensor providing the data and metadata.
+ * @param ret_dst On output, this will point to the new tensor view.
+ *
+ * @return Error::Ok on success, appropriate error code on failure:
+ *         - Error::InvalidArgument: null pointers or memory not tracked
+ */
+AOTI_SHIM_EXPORT AOTITorchError
+aoti_torch_assign_tensors_out(Tensor* src, Tensor** ret_dst);
 
 // Function to clear all tensors from internal storage
 AOTI_SHIM_EXPORT void clear_all_tensors();

backends/cuda/runtime/shims/tests/CMakeLists.txt

@@ -37,9 +37,14 @@ find_package(executorch CONFIG REQUIRED HINTS ${CMAKE_INSTALL_PREFIX})
 
 # List of test files
 set(CUDA_SHIM_TESTS
-    test_aoti_torch_create_tensor_from_blob_v2 test_aoti_torch_empty_strided
-    test_aoti_torch_delete_tensor_object test_aoti_torch__reinterpret_tensor
-    test_aoti_torch_copy_ test_aoti_torch_new_tensor_handle
+    test_aoti_torch_create_tensor_from_blob_v2
+    test_aoti_torch_empty_strided
+    test_aoti_torch_delete_tensor_object
+    test_aoti_torch__reinterpret_tensor
+    test_aoti_torch_copy_
+    test_aoti_torch_new_tensor_handle
+    test_aoti_torch_item_bool
+    test_aoti_torch_assign_tensors_out
 )
 
 enable_testing()

backends/cuda/runtime/shims/tests/targets.bzl

@@ -35,3 +35,5 @@ def define_common_targets():
     cuda_shim_cpp_unittest("aoti_torch_cuda_guard")
     cuda_shim_cpp_unittest("aoti_torch_cuda__weight_int4pack_mm")
     cuda_shim_cpp_unittest("aoti_torch_new_tensor_handle")
+    cuda_shim_cpp_unittest("aoti_torch_item_bool")
+    cuda_shim_cpp_unittest("aoti_torch_assign_tensors_out")