chore: import upstream snapshot with attribution

include/tvm/ir/function.h

@@ -0,0 +1,256 @@
+/*
+ * 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/ir/function.h
+ * \brief Function nodes.
+ */
+#ifndef TVM_IR_FUNCTION_H_
+#define TVM_IR_FUNCTION_H_
+
+#include <tvm/ffi/container/array.h>
+#include <tvm/ffi/container/map.h>
+#include <tvm/ffi/string.h>
+#include <tvm/ir/attrs.h>
+#include <tvm/ir/expr.h>
+
+#include <string>
+#include <type_traits>
+
+namespace tvm {
+
+/*!
+ * \brief Possible Calling conventions.
+ *
+ *  NOTE: The calling convention also implies
+ *  the way we implement the function during lowering.
+ */
+enum class CallingConv : int {
+  /*!
+   * \brief Default calling convention.
+   *
+   * - Uses the native calling convention of the target.
+   * - Implementation: specified by the native target.
+   */
+  kDefault = 0,
+  /*!
+   * \brief ffi::Function that exposes a Cffi::Function signature.
+   *
+   * - Calling by ffi::Function calling convention.
+   * - Implementation: Expose a function with the Cffi::Function signature.
+   */
+  kCPackedFunc = 1,
+  /*!
+   * \brief Device kernel launch
+   *
+   * - Call by ffi::Function calling convention.
+   * - Implementation: defined by device runtime(e.g. runtime/cuda)
+   */
+  kDeviceKernelLaunch = 2,
+};
+
+/*!
+ * \brief Supported linkage types.
+ */
+enum class LinkageType : int {
+  /*!
+   * \brief Internal linkage.
+   */
+  kInternal = 0,
+  /*!
+   * \brief External linkage.
+   - Function with external linkage should have a global symbol attached to it.
+   */
+  kExternal = 1
+};
+
+/*!
+ * \brief Generic attribute names that can be attached to any function.
+ *
+ * \sa tvm::tirx::attr, tvm::relax::attr
+ */
+namespace attr {
+/*!
+ * \brief Indicates the special calling convention.
+ *
+ * Type: IntImm
+ *
+ * \sa tvm::CallingConv
+ */
+constexpr const char* kCallingConv = "calling_conv";
+
+/*!
+ * \brief Compilation target of the function.
+ *
+ * Type: Target
+ *
+ * \sa tvm::Target
+ */
+constexpr const char* kTarget = "target";
+
+/*!
+ * \brief Global linker symbol of the function in generated code.
+ *
+ *  This option forces the code generator to name the
+ *  function with the given.
+ *
+ *  For example, we could set a global_symbol of a function
+ *  early to make sure that we can always refer to it by
+ *  the symbol name in the generated DLL.
+ *
+ *  We should not set the attribute for local functions,
+ *  so that the compiler can freely rename them.
+ *
+ *  A unique global symbol will be automatically assigned
+ *  to each function in the module before the target code
+ *  generation phase.
+ *
+ * Type: String
+ */
+constexpr const char* kGlobalSymbol = "global_symbol";
+
+/*!
+ * \brief The function uses s_tir (apache-derived TIR) semantics:
+ *        parser fills layout=None, ScriptComplete wraps body in a root SBlock,
+ *        and printer emits `s_tir=True` on the decorator.
+ *        Default (attr absent or False) is tirx semantics.
+ *
+ * Type: IntImm (bool dtype)
+ */
+constexpr const char* kSTir = "s_tir";
+
+/*!
+ * \brief Number of inputs of the Primfunc
+ *
+ * Type: Int
+ */
+constexpr const char* kNumInputs = "num_inputs";
+
+}  // namespace attr
+
+/*!
+ * \brief Base node of all functions.
+ *
+ * We support several variants of functions throughout the stack.
+ * All of the functions share the same type system
+ * to support cross variant calls.
+ *
+ * \sa BaseFunc
+ */
+class BaseFuncNode : public ExprNode {
+ public:
+  /*! \brief Additional attributes storing the meta-data */
+  DictAttrs attrs;
+
+  /*!
+   * \brief Get a function attribute.
+   *
+   * \param attr_key The attribute key.
+   * \param default_value The default value if the key does not exist, defaults to nullptr.
+   *
+   * \return The result
+   *
+   * \tparam TOBjectRef the expected object type.
+   * \throw Error if the key exists but the value does not match TObjectRef
+   *
+   * \code
+   *
+   *  void GetAttrExample(const BaseFunc& f) {
+   *    auto value = f->GetAttr<int64_t>("AttrKey", 0);
+   *  }
+   *
+   * \endcode
+   */
+  template <typename TObjectRef>
+  ffi::Optional<TObjectRef> GetAttr(const std::string& attr_key,
+                                    ffi::Optional<TObjectRef> default_value = std::nullopt) const {
+    return attrs.GetAttr(attr_key, default_value);
+  }
+  // variant that uses TObjectRef to enable implicit conversion to default value.
+  template <typename TObjectRef>
+  ffi::Optional<TObjectRef> GetAttr(const std::string& attr_key, TObjectRef default_value) const {
+    return GetAttr<TObjectRef>(attr_key, ffi::Optional<TObjectRef>(default_value));
+  }
+
+  /*!
+   * \brief Check whether the function has an non-zero integer attr.
+   *
+   * This function can be used to check whether an optional
+   * attribute mark(e.g. inline) exists.
+   *
+   * \param attr_key The key to the attribute.
+   * \return The check result.
+   *
+   * \code
+   *
+   *  void HasNonzeroAttrExample(const BaseFunc& f) {
+   *    if (f->HasNonzeroAttr(attr::kInline)) {
+   *      // inline the function.
+   *    }
+   *  }
+   *
+   * \endcode
+   */
+  bool HasNonzeroAttr(const std::string& attr_key) const { return attrs.HasNonzeroAttr(attr_key); }
+  /*!
+   * \brief Get the type of the linkage.
+   *
+   * Currently, we only consider external/internal linkage.
+   * This can be extended in the future when necessary.
+   *
+   * \return Linkage type.
+   *
+   * \code
+   *
+   *  void Example(const BaseFunc& f) {
+   *    if (f->GetLinkageType() == tvm::LinkageType::kExternal) {
+   *      // Do not remove a function with external linkage
+   *    }
+   *  }
+   *
+   * \endcode
+   */
+
+  LinkageType GetLinkageType() const {
+    if (GetAttr<ffi::String>(attr::kGlobalSymbol))
+      return LinkageType::kExternal;
+    else
+      return LinkageType::kInternal;
+  }
+
+  static void RegisterReflection() {
+    namespace refl = tvm::ffi::reflection;
+    refl::ObjectDef<BaseFuncNode>().def_ro("attrs", &BaseFuncNode::attrs);
+  }
+
+  static constexpr const uint32_t _type_child_slots = 2;
+  TVM_FFI_DECLARE_OBJECT_INFO("ir.BaseFunc", BaseFuncNode, ExprNode);
+};
+
+/*!
+ * \brief Managed reference to BaseFuncNode.
+ * \sa BaseFuncNode
+ */
+class BaseFunc : public Expr {
+ public:
+  TVM_FFI_DEFINE_OBJECT_REF_METHODS_NULLABLE(BaseFunc, Expr, BaseFuncNode);
+};
+
+}  // namespace tvm
+#endif  // TVM_IR_FUNCTION_H_