eigen/unsupported/test/cxx11_tensor_move.cpp
Antonio Sanchez 543e34ab9d Re-implement move assignments.
The original swap approach leads to potential undefined behavior (reading
uninitialized memory) and results in unnecessary copying of data for static
storage.

Here we pass down the move assignment to the underlying storage.  Static
storage does a one-way copy, dynamic storage does a swap.

Modified the tests to no longer read from the moved-from matrix/tensor,
since that can lead to UB. Added a test to ensure we do not access
uninitialized memory in a move.

Fixes: #2119
2021-03-10 16:55:20 +00:00

77 lines
1.7 KiB
C++

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2017 Viktor Csomor <viktor.csomor@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#include "main.h"
#include <Eigen/CXX11/Tensor>
#include <utility>
using Eigen::Tensor;
using Eigen::RowMajor;
static void calc_indices(int i, int& x, int& y, int& z)
{
x = i / 4;
y = (i % 4) / 2;
z = i % 2;
}
static void test_move()
{
int x;
int y;
int z;
Tensor<int,3> tensor1(2, 2, 2);
Tensor<int,3,RowMajor> tensor2(2, 2, 2);
for (int i = 0; i < 8; i++)
{
calc_indices(i, x, y, z);
tensor1(x,y,z) = i;
tensor2(x,y,z) = 2 * i;
}
// Invokes the move constructor.
Tensor<int,3> moved_tensor1 = std::move(tensor1);
Tensor<int,3,RowMajor> moved_tensor2 = std::move(tensor2);
VERIFY_IS_EQUAL(tensor1.size(), 0);
VERIFY_IS_EQUAL(tensor2.size(), 0);
for (int i = 0; i < 8; i++)
{
calc_indices(i, x, y, z);
VERIFY_IS_EQUAL(moved_tensor1(x,y,z), i);
VERIFY_IS_EQUAL(moved_tensor2(x,y,z), 2 * i);
}
Tensor<int,3> moved_tensor3(2,2,2);
Tensor<int,3,RowMajor> moved_tensor4(2,2,2);
moved_tensor3.setZero();
moved_tensor4.setZero();
// Invokes the move assignment operator.
moved_tensor3 = std::move(moved_tensor1);
moved_tensor4 = std::move(moved_tensor2);
for (int i = 0; i < 8; i++)
{
calc_indices(i, x, y, z);
VERIFY_IS_EQUAL(moved_tensor3(x,y,z), i);
VERIFY_IS_EQUAL(moved_tensor4(x,y,z), 2 * i);
}
}
EIGEN_DECLARE_TEST(cxx11_tensor_move)
{
CALL_SUBTEST(test_move());
}