lld/unittests/CoreTests/ParallelTest.cpp

//===- lld/unittest/ParallelTest.cpp --------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief Parallel.h unit tests.
///
//===----------------------------------------------------------------------===//

#include "gtest/gtest.h"
#include "lld/Core/Parallel.h"
#include <array>
#include <random>

uint32_t array[1024 * 1024];

TEST(Parallel, sort) {
  std::mt19937 randEngine;
  std::uniform_int_distribution<uint32_t> dist;

  for (auto &i : array)
    i = dist(randEngine);

  sort(lld::parallel::par, std::begin(array), std::end(array));
  ASSERT_TRUE(std::is_sorted(std::begin(array), std::end(array)));
}

TEST(Parallel, parallel_for) {
  // We need to test the case with a TaskSize > 1. We are white-box testing
  // here. The TaskSize is calculated as (End - Begin) / 1024 at the time of
  // writing.
  uint32_t range[2050];
  std::fill(range, range + 2050, 1);
  for_each_n(lld::parallel::par, 0, 2049, [&range](size_t I) { ++range[I]; });

  uint32_t expected[2049];
  std::fill(expected, expected + 2049, 2);
  ASSERT_TRUE(std::equal(range, range + 2049, expected));
  // Check that we don't write past the end of the requested range.
  ASSERT_EQ(range[2049], 1u);
}