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wit/wasi-nn.wit

@@ -18,16 +18,17 @@ world ml {
 /// Inference is performed on a specific `device`.
 interface device {
     /// Define where tensors reside and graphs execute.
-    enum location {
-        cpu,
-        gpu,
-        tpu
+    record device {
+        name: string
     }
+
+    /// List the available devices for a given backend.
+    available-devices: func(backend: backend) -> list<device>;
 }
 
 /// All inputs and outputs to an ML inference are represented as `tensor`s.
 interface tensor {
-    use device.{location};
+    use device.{device};
 
     /// The dimensions of a tensor.
     ///
@@ -67,26 +68,23 @@ interface tensor {
         ty: func() -> tensor-type;
 
         // Describe where the tensor is currently located (e.g., `cpu`, `gpu`, `tpu`).
-        location: func() -> location;
+        location: func() -> device;
+
+        // Move the tensor to a different device. This operation may result in an expensive data
+        // copy.
+        move-to: func(device: device) -> result<tensor, error>;
 
         // Return the tensor data. If the tensor is located on a device other than the CPU, this
         // operation may result in an expensive data copy operation.
         data: func() -> tensor-data;
     }
-
-    /// Alternately, construct a tensor that lives exclusively on a specific device.
-    create_on_device: func(dimensions: tensor-dimensions, ty: tensor-type, data: tensor-data,
-        location: execution-target, backend: graph-encoding) -> result<tensor, error>;
-
-    // TODO: rename exection-target to... device?
-    // TODO: rename graph-encoding to... backend?
 }
 
 /// A `graph` is a loaded instance of a specific ML model (e.g., MobileNet) for a specific ML
 /// framework (e.g., TensorFlow):
 interface graph {
     use errors.{error};
-    use device.{location};
+    use device.{device};
     use inference.{graph-execution-context};
     use tensor.{tensor};
 
@@ -114,7 +112,7 @@ interface graph {
 
     /// Load a `graph` from an opaque sequence of bytes to use for inference on the specified device
     /// `location`.
-    load: func(builder: list<graph-builder>, encoding: graph-encoding, location: location) -> result<graph, error>;
+    load: func(builder: list<graph-builder>, encoding: graph-encoding, location: device) -> result<graph, error>;
 
     /// Load a `graph` by name.
     ///