reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
  150
  151
  152
  153
  154
  155
  156
  157
  158
  159
  160
  161
  162
  163
  164
  165
  166
  167
  168
  169
  170
  171
  172
  173
  174
  175
  176
  177
  178
  179
  180
  181
  182
  183
  184
  185
  186
  187
  188
  189
  190
  191
  192
  193
  194
  195
  196
  197
  198
  199
  200
  201
  202
  203
  204
  205
  206
  207
  208
  209
  210
  211
  212
  213
  214
  215
  216
  217
  218
  219
  220
  221
  222
  223
  224
  225
  226
  227
//===- FunctionExtrasTest.cpp - Unit tests for function type erasure ------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/FunctionExtras.h"
#include "gtest/gtest.h"

#include <memory>

using namespace llvm;

namespace {

TEST(UniqueFunctionTest, Basic) {
  unique_function<int(int, int)> Sum = [](int A, int B) { return A + B; };
  EXPECT_EQ(Sum(1, 2), 3);

  unique_function<int(int, int)> Sum2 = std::move(Sum);
  EXPECT_EQ(Sum2(1, 2), 3);

  unique_function<int(int, int)> Sum3 = [](int A, int B) { return A + B; };
  Sum2 = std::move(Sum3);
  EXPECT_EQ(Sum2(1, 2), 3);

  Sum2 = unique_function<int(int, int)>([](int A, int B) { return A + B; });
  EXPECT_EQ(Sum2(1, 2), 3);

  // Explicit self-move test.
  *&Sum2 = std::move(Sum2);
  EXPECT_EQ(Sum2(1, 2), 3);

  Sum2 = unique_function<int(int, int)>();
  EXPECT_FALSE(Sum2);

  // Make sure we can forward through l-value reference parameters.
  unique_function<void(int &)> Inc = [](int &X) { ++X; };
  int X = 42;
  Inc(X);
  EXPECT_EQ(X, 43);

  // Make sure we can forward through r-value reference parameters with
  // move-only types.
  unique_function<int(std::unique_ptr<int> &&)> ReadAndDeallocByRef =
      [](std::unique_ptr<int> &&Ptr) {
        int V = *Ptr;
        Ptr.reset();
        return V;
      };
  std::unique_ptr<int> Ptr{new int(13)};
  EXPECT_EQ(ReadAndDeallocByRef(std::move(Ptr)), 13);
  EXPECT_FALSE((bool)Ptr);

  // Make sure we can pass a move-only temporary as opposed to a local variable.
  EXPECT_EQ(ReadAndDeallocByRef(std::unique_ptr<int>(new int(42))), 42);

  // Make sure we can pass a move-only type by-value.
  unique_function<int(std::unique_ptr<int>)> ReadAndDeallocByVal =
      [](std::unique_ptr<int> Ptr) {
        int V = *Ptr;
        Ptr.reset();
        return V;
      };
  Ptr.reset(new int(13));
  EXPECT_EQ(ReadAndDeallocByVal(std::move(Ptr)), 13);
  EXPECT_FALSE((bool)Ptr);

  EXPECT_EQ(ReadAndDeallocByVal(std::unique_ptr<int>(new int(42))), 42);
}

TEST(UniqueFunctionTest, Captures) {
  long A = 1, B = 2, C = 3, D = 4, E = 5;

  unique_function<long()> Tmp;

  unique_function<long()> C1 = [A]() { return A; };
  EXPECT_EQ(C1(), 1);
  Tmp = std::move(C1);
  EXPECT_EQ(Tmp(), 1);

  unique_function<long()> C2 = [A, B]() { return A + B; };
  EXPECT_EQ(C2(), 3);
  Tmp = std::move(C2);
  EXPECT_EQ(Tmp(), 3);

  unique_function<long()> C3 = [A, B, C]() { return A + B + C; };
  EXPECT_EQ(C3(), 6);
  Tmp = std::move(C3);
  EXPECT_EQ(Tmp(), 6);

  unique_function<long()> C4 = [A, B, C, D]() { return A + B + C + D; };
  EXPECT_EQ(C4(), 10);
  Tmp = std::move(C4);
  EXPECT_EQ(Tmp(), 10);

  unique_function<long()> C5 = [A, B, C, D, E]() { return A + B + C + D + E; };
  EXPECT_EQ(C5(), 15);
  Tmp = std::move(C5);
  EXPECT_EQ(Tmp(), 15);
}

TEST(UniqueFunctionTest, MoveOnly) {
  struct SmallCallable {
    std::unique_ptr<int> A{new int(1)};

    int operator()(int B) { return *A + B; }
  };
  unique_function<int(int)> Small = SmallCallable();
  EXPECT_EQ(Small(2), 3);
  unique_function<int(int)> Small2 = std::move(Small);
  EXPECT_EQ(Small2(2), 3);

  struct LargeCallable {
    std::unique_ptr<int> A{new int(1)};
    std::unique_ptr<int> B{new int(2)};
    std::unique_ptr<int> C{new int(3)};
    std::unique_ptr<int> D{new int(4)};
    std::unique_ptr<int> E{new int(5)};

    int operator()() { return *A + *B + *C + *D + *E; }
  };
  unique_function<int()> Large = LargeCallable();
  EXPECT_EQ(Large(), 15);
  unique_function<int()> Large2 = std::move(Large);
  EXPECT_EQ(Large2(), 15);
}

TEST(UniqueFunctionTest, CountForwardingCopies) {
  struct CopyCounter {
    int &CopyCount;

    CopyCounter(int &CopyCount) : CopyCount(CopyCount) {}
    CopyCounter(const CopyCounter &Arg) : CopyCount(Arg.CopyCount) {
      ++CopyCount;
    }
  };

  unique_function<void(CopyCounter)> ByValF = [](CopyCounter) {};
  int CopyCount = 0;
  ByValF(CopyCounter(CopyCount));
  EXPECT_EQ(1, CopyCount);

  CopyCount = 0;
  {
    CopyCounter Counter{CopyCount};
    ByValF(Counter);
  }
  EXPECT_EQ(2, CopyCount);

  // Check that we don't generate a copy at all when we can bind a reference all
  // the way down, even if that reference could *in theory* allow copies.
  unique_function<void(const CopyCounter &)> ByRefF = [](const CopyCounter &) {
  };
  CopyCount = 0;
  ByRefF(CopyCounter(CopyCount));
  EXPECT_EQ(0, CopyCount);

  CopyCount = 0;
  {
    CopyCounter Counter{CopyCount};
    ByRefF(Counter);
  }
  EXPECT_EQ(0, CopyCount);

  // If we use a reference, we can make a stronger guarantee that *no* copy
  // occurs.
  struct Uncopyable {
    Uncopyable() = default;
    Uncopyable(const Uncopyable &) = delete;
  };
  unique_function<void(const Uncopyable &)> UncopyableF =
      [](const Uncopyable &) {};
  UncopyableF(Uncopyable());
  Uncopyable X;
  UncopyableF(X);
}

TEST(UniqueFunctionTest, CountForwardingMoves) {
  struct MoveCounter {
    int &MoveCount;

    MoveCounter(int &MoveCount) : MoveCount(MoveCount) {}
    MoveCounter(MoveCounter &&Arg) : MoveCount(Arg.MoveCount) { ++MoveCount; }
  };

  unique_function<void(MoveCounter)> ByValF = [](MoveCounter) {};
  int MoveCount = 0;
  ByValF(MoveCounter(MoveCount));
  EXPECT_EQ(1, MoveCount);

  MoveCount = 0;
  {
    MoveCounter Counter{MoveCount};
    ByValF(std::move(Counter));
  }
  EXPECT_EQ(2, MoveCount);

  // Check that when we use an r-value reference we get no spurious copies.
  unique_function<void(MoveCounter &&)> ByRefF = [](MoveCounter &&) {};
  MoveCount = 0;
  ByRefF(MoveCounter(MoveCount));
  EXPECT_EQ(0, MoveCount);

  MoveCount = 0;
  {
    MoveCounter Counter{MoveCount};
    ByRefF(std::move(Counter));
  }
  EXPECT_EQ(0, MoveCount);

  // If we use an r-value reference we can in fact make a stronger guarantee
  // with an unmovable type.
  struct Unmovable {
    Unmovable() = default;
    Unmovable(Unmovable &&) = delete;
  };
  unique_function<void(const Unmovable &)> UnmovableF = [](const Unmovable &) {
  };
  UnmovableF(Unmovable());
  Unmovable X;
  UnmovableF(X);
}

} // anonymous namespace