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/*
* kmp_utils.h -- Utilities that used internally
*/
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef __KMP_UTILS_H__
#define __KMP_UTILS_H__
#include <cstddef>
#include "kmp.h"
/// A simple pure header implementation of VLA that aims to replace uses of
/// actual VLA, which can cause compile warning. This class by default creates a
/// stack buffer that can accomodate \p N elements. If the number of elements is
/// greater than \p N, then a heap buffer will be allocated and used to
/// accomodate the elements. Similar to the actual VLA, we don't check boundary
/// (for now), so we will not store the number of elements. We can always revise
/// it later.
template <typename T, unsigned N = 8> class SimpleVLA final {
T StackBuffer[N];
T *HeapBuffer = nullptr;
T *Ptr = StackBuffer;
public:
SimpleVLA() = delete;
SimpleVLA(const SimpleVLA &) = delete;
SimpleVLA(SimpleVLA &&) = delete;
SimpleVLA &operator=(const SimpleVLA &) = delete;
SimpleVLA &operator=(SimpleVLA &&) = delete;
explicit SimpleVLA(unsigned NumOfElements) noexcept {
if (NumOfElements > N) {
HeapBuffer =
reinterpret_cast<T *>(__kmp_allocate(NumOfElements * sizeof(T)));
Ptr = HeapBuffer;
}
}
~SimpleVLA() {
if (HeapBuffer)
__kmp_free(HeapBuffer);
}
operator T *() noexcept { return Ptr; }
operator const T *() const noexcept { return Ptr; }
};
#endif
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