chore: import upstream snapshot with attribution

include/tvm/runtime/c_backend_api.h

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+/*
+ * 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 tvm/runtime/c_backend_api.h
+ * \brief TVM runtime backend API.
+ *
+ *  The functions defined in this header are intended to be
+ *  used by compiled tvm operators, usually user do not need to use these
+ *  function directly.
+ */
+#ifndef TVM_RUNTIME_C_BACKEND_API_H_
+#define TVM_RUNTIME_C_BACKEND_API_H_
+
+#include <tvm/runtime/base.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*!
+ * \brief Backend function to allocate temporal workspace.
+ *
+ * \note The result allocated space is ensured to be aligned to kTempAllocaAlignment.
+ *
+ * \param nbytes The size of the space requested.
+ * \param device_type The device type which the space will be allocated.
+ * \param device_id The device id which the space will be allocated.
+ * \param dtype_code_hint The type code of the array elements. Only used in
+ * certain backends such as OpenGL.
+ * \param dtype_bits_hint The type bits of the array elements. Only used in
+ * certain backends such as OpenGL.
+ * \return nullptr when error is thrown, a valid ptr if success
+ */
+TVM_RUNTIME_DLL void* TVMBackendAllocWorkspace(int device_type, int device_id, uint64_t nbytes,
+                                               int dtype_code_hint, int dtype_bits_hint);
+
+/*!
+ * \brief Backend function to free temporal workspace.
+ *
+ * \param ptr The result allocated space pointer.
+ * \param device_type The device type which the space will be allocated.
+ * \param device_id The device id which the space will be allocated.
+ * \return 0 when no error is thrown, -1 when failure happens
+ *
+ * \sa TVMBackendAllocWorkspace
+ */
+TVM_RUNTIME_DLL int TVMBackendFreeWorkspace(int device_type, int device_id, void* ptr);
+
+/*!
+ * \brief Environment for TVM parallel task.
+ */
+typedef struct {
+  /*!
+   * \brief Auxiliary used for synchronization
+   */
+  void* sync_handle;
+  /*! \brief total amount of task */
+  int32_t num_task;
+} TVMParallelGroupEnv;
+
+/*!
+ * \brief The callback function to execute a parallel lambda
+ * \param task_id the task id of the function.
+ * \param penv The parallel environment backs the execution.
+ * \param cdata The supporting closure data.
+ */
+typedef int (*FTVMParallelLambda)(int task_id, TVMParallelGroupEnv* penv, void* cdata);
+
+/*!
+ * \brief Backend function for running parallel jobs.
+ *
+ * \param flambda The parallel function to be launched.
+ * \param cdata The closure data.
+ * \param num_task Number of tasks to launch, can be 0, means launch
+ *           with all available threads.
+ *
+ * \return 0 when no error is thrown, -1 when failure happens
+ */
+TVM_RUNTIME_DLL int TVMBackendParallelLaunch(FTVMParallelLambda flambda, void* cdata, int num_task);
+
+/*!
+ * \brief BSP barrrier between parallel threads
+ * \param task_id the task id of the function.
+ * \param penv The parallel environment backs the execution.
+ * \return 0 when no error is thrown, -1 when failure happens
+ */
+TVM_RUNTIME_DLL int TVMBackendParallelBarrier(int task_id, TVMParallelGroupEnv* penv);
+
+#ifdef __cplusplus
+}  // TVM_EXTERN_C
+#endif
+#endif  // TVM_RUNTIME_C_BACKEND_API_H_