unittests/Support/TrailingObjectsTest.cpp

   1 //=== - llvm/unittest/Support/TrailingObjectsTest.cpp ---------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/Support/TrailingObjects.h"
  11 #include "gtest/gtest.h"
  12
  13 using namespace llvm;
  14
  15 namespace {
  16 // This class, beyond being used by the test case, a nice
  17 // demonstration of the intended usage of TrailingObjects, with a
  18 // single trailing array.
  19 class Class1 final : private TrailingObjects<Class1, short> {
  20   friend TrailingObjects;
  21
  22   unsigned NumShorts;
  23
  24 protected:
  25   size_t numTrailingObjects(OverloadToken<short>) const { return NumShorts; }
  26
  27   Class1(int *ShortArray, unsigned NumShorts) : NumShorts(NumShorts) {
  28     std::uninitialized_copy(ShortArray, ShortArray + NumShorts,
  29                             getTrailingObjects<short>());
  30   }
  31
  32 public:
  33   static Class1 *create(int *ShortArray, unsigned NumShorts) {
  34     void *Mem = ::operator new(totalSizeToAlloc<short>(NumShorts));
  35     return new (Mem) Class1(ShortArray, NumShorts);
  36   }
  37
  38   short get(unsigned Num) const { return getTrailingObjects<short>()[Num]; }
  39
  40   unsigned numShorts() const { return NumShorts; }
  41
  42   // Pull some protected members in as public, for testability.
  43   using TrailingObjects::totalSizeToAlloc;
  44   using TrailingObjects::additionalSizeToAlloc;
  45   using TrailingObjects::getTrailingObjects;
  46 };
  47
  48 // Here, there are two singular optional object types appended.
  49 // Note that it fails to compile without the alignment spec.
  50 class LLVM_ALIGNAS(8) Class2 final : private TrailingObjects<Class2, double, short> {
  51   friend TrailingObjects;
  52
  53   bool HasShort, HasDouble;
  54
  55 protected:
  56   size_t numTrailingObjects(OverloadToken<short>) const {
  57     return HasShort ? 1 : 0;
  58   }
  59   size_t numTrailingObjects(OverloadToken<double>) const {
  60     return HasDouble ? 1 : 0;
  61   }
  62
  63   Class2(bool HasShort, bool HasDouble)
  64       : HasShort(HasShort), HasDouble(HasDouble) {}
  65
  66 public:
  67   static Class2 *create(short S = 0, double D = 0.0) {
  68     bool HasShort = S != 0;
  69     bool HasDouble = D != 0.0;
  70
  71     void *Mem =
  72         ::operator new(totalSizeToAlloc<double, short>(HasDouble, HasShort));
  73     Class2 *C = new (Mem) Class2(HasShort, HasDouble);
  74     if (HasShort)
  75       *C->getTrailingObjects<short>() = S;
  76     if (HasDouble)
  77       *C->getTrailingObjects<double>() = D;
  78     return C;
  79   }
  80
  81   short getShort() const {
  82     if (!HasShort)
  83       return 0;
  84     return *getTrailingObjects<short>();
  85   }
  86
  87   double getDouble() const {
  88     if (!HasDouble)
  89       return 0.0;
  90     return *getTrailingObjects<double>();
  91   }
  92
  93   // Pull some protected members in as public, for testability.
  94   using TrailingObjects::totalSizeToAlloc;
  95   using TrailingObjects::additionalSizeToAlloc;
  96   using TrailingObjects::getTrailingObjects;
  97 };
  98
  99 TEST(TrailingObjects, OneArg) {
 100   int arr[] = {1, 2, 3};
 101   Class1 *C = Class1::create(arr, 3);
 102   EXPECT_EQ(sizeof(Class1), sizeof(unsigned));
 103   EXPECT_EQ(Class1::additionalSizeToAlloc<short>(1), sizeof(short));
 104   EXPECT_EQ(Class1::additionalSizeToAlloc<short>(3), sizeof(short) * 3);
 105
 106   EXPECT_EQ(Class1::totalSizeToAlloc<short>(1), sizeof(Class1) + sizeof(short));
 107   EXPECT_EQ(Class1::totalSizeToAlloc<short>(3),
 108             sizeof(Class1) + sizeof(short) * 3);
 109
 110   EXPECT_EQ(C->getTrailingObjects<short>(), reinterpret_cast<short *>(C + 1));
 111   EXPECT_EQ(C->get(0), 1);
 112   EXPECT_EQ(C->get(2), 3);
 113   delete C;
 114 }
 115
 116 TEST(TrailingObjects, TwoArg) {
 117   Class2 *C1 = Class2::create(4);
 118   Class2 *C2 = Class2::create(0, 4.2);
 119
 120   EXPECT_EQ(sizeof(Class2), 8u); // due to alignment
 121
 122   EXPECT_EQ((Class2::additionalSizeToAlloc<double, short>(1, 0)),
 123             sizeof(double));
 124   EXPECT_EQ((Class2::additionalSizeToAlloc<double, short>(0, 1)),
 125             sizeof(short));
 126   EXPECT_EQ((Class2::additionalSizeToAlloc<double, short>(3, 1)),
 127             sizeof(double) * 3 + sizeof(short));
 128
 129   EXPECT_EQ((Class2::totalSizeToAlloc<double, short>(1, 1)),
 130             sizeof(Class2) + sizeof(double) + sizeof(short));
 131
 132   EXPECT_EQ(C1->getDouble(), 0);
 133   EXPECT_EQ(C1->getShort(), 4);
 134   EXPECT_EQ(C1->getTrailingObjects<double>(),
 135             reinterpret_cast<double *>(C1 + 1));
 136   EXPECT_EQ(C1->getTrailingObjects<short>(), reinterpret_cast<short *>(C1 + 1));
 137
 138   EXPECT_EQ(C2->getDouble(), 4.2);
 139   EXPECT_EQ(C2->getShort(), 0);
 140   EXPECT_EQ(C2->getTrailingObjects<double>(),
 141             reinterpret_cast<double *>(C2 + 1));
 142   EXPECT_EQ(C2->getTrailingObjects<short>(),
 143             reinterpret_cast<short *>(reinterpret_cast<double *>(C2 + 1) + 1));
 144   delete C1;
 145   delete C2;
 146 }
 147 }