scope_stack.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.
 */
 
#ifndef TVM_IR_SCOPE_STACK_H_
#define TVM_IR_SCOPE_STACK_H_
 
#include <tvm/ffi/error.h>
 
#include <deque>
#include <type_traits>
 
namespace tvm {
 
template <typename T>
class ScopeStack {
 public:
  ScopeStack() { stack_.emplace_back(); }
 
  size_t size() const { return stack_.size(); }
 
  bool empty() const { return stack_.empty(); }
 
  T& Current() {
    TVM_FFI_ICHECK(!stack_.empty());
    return stack_.back();
  }
 
  const T& Current() const {
    TVM_FFI_ICHECK(!stack_.empty());
    return stack_.back();
  }
 
  template <typename F>
  auto WithNewScope(F&& body) -> decltype(body()) {
    stack_.emplace_back();
    struct Guard {
      std::deque<T>* stack;
      ~Guard() noexcept(false) { stack->pop_back(); }
    } guard{&stack_};
    if constexpr (std::is_void_v<decltype(body())>) {
      body();
    } else {
      return body();
    }
  }
 
 private:
  std::deque<T> stack_;
};
 
}  // namespace tvm
 
#endif  // TVM_IR_SCOPE_STACK_H_