[FFI][DOCS] Add missing files in packaging example

ffi/examples/packaging/run_example.py

@@ -0,0 +1,40 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations.
+# Base logic to load library for extension package
+import torch
+import sys
+import tvm_ffi_extension
+
+
+def run_add_one():
+    x = torch.tensor([1, 2, 3, 4, 5], dtype=torch.float32)
+    y = torch.empty_like(x)
+    tvm_ffi_extension.add_one(x, y)
+    print(y)
+
+
+def run_raise_error():
+    tvm_ffi_extension.raise_error("This is an error")
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        if sys.argv[1] == "add_one":
+            run_add_one()
+        elif sys.argv[1] == "raise_error":
+            run_raise_error()
+    else:
+        print("Usage: python run_example.py <add_one|raise_error>")

ffi/examples/packaging/src/extension.cc

@@ -0,0 +1,88 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+/*!
+ * \file example.cc
+ * \brief Example of a tvm-ffi based library that registers various functions.
+ *
+ * It is a simple example that demonstrates how to package a tvm-ffi library into a python wheel.
+ * The library is written in C++ and can be compiled into a shared library.
+ * The shared library can then be loaded into python and used to call the functions.
+ */
+#include <tvm/ffi/dtype.h>
+#include <tvm/ffi/error.h>
+#include <tvm/ffi/function.h>
+#include <tvm/ffi/reflection/registry.h>
+
+namespace tvm_ffi_extension {
+
+namespace ffi = tvm::ffi;
+
+/*!
+ * \brief Raises a runtime error
+ *
+ * This is an example function to show how to raise and propagate
+ * an error across the language boundary.
+ *
+ * \param msg The message to raise the error with
+ */
+void RaiseError(ffi::String msg) { TVM_FFI_THROW(RuntimeError) << msg; }
+
+void AddOne(DLTensor* x, DLTensor* y) {
+  // implementation of a library function
+  TVM_FFI_ICHECK(x->ndim == 1) << "x must be a 1D tensor";
+  DLDataType f32_dtype{kDLFloat, 32, 1};
+  TVM_FFI_ICHECK(x->dtype == f32_dtype) << "x must be a float tensor";
+  TVM_FFI_ICHECK(y->ndim == 1) << "y must be a 1D tensor";
+  TVM_FFI_ICHECK(y->dtype == f32_dtype) << "y must be a float tensor";
+  TVM_FFI_ICHECK(x->shape[0] == y->shape[0]) << "x and y must have the same shape";
+  for (int i = 0; i < x->shape[0]; ++i) {
+    static_cast<float*>(y->data)[i] = static_cast<float*>(x->data)[i] + 1;
+  }
+}
+
+// expose global symbol add_one
+TVM_FFI_DLL_EXPORT_TYPED_FUNC(add_one, tvm_ffi_extension::AddOne);
+
+// The static initialization block is
+// called once when the library is loaded.
+TVM_FFI_STATIC_INIT_BLOCK({
+  namespace refl = tvm::ffi::reflection;
+  // In this particular example, we use the reflection mechanisms to
+  // register the functions directly into the global function table.
+  //
+  // This is an alternative approach to TVM_FFI_DLL_EXPORT_TYPED_FUNC
+  // that exports the function directly as C symbol that follows tvm-ffi abi.
+  //
+  // - For functions that are expected to be static part of tvm_ffi_example project,
+  //   one can use reflection mechanisms to register the globa function.
+  // - For functions that are compiled and dynamically loaded at runtime, consider
+  //   using the normal export mechanism so they won't be exposed to the global function table.
+  //
+  // Make sure to have a unique name across all registered functions,
+  // always prefix with a package namespace name to avoid name collision.
+  //
+  // The function can then be found via tvm_ffi.get_global_func(name)
+  // If the function is expected to stay throughout the lifetime of the program/
+  //
+  // When registering via reflection mechanisms, the library do not need to be loaded via
+  // tvm::ffi::Module::LoadFromFile, instead, just load the dll or simply bundle into the
+  // final project
+  refl::GlobalDef().def("tvm_ffi_extension.raise_error", RaiseError);
+});
+}  // namespace tvm_ffi_extension