llvm/unittests/ADT/PointerIntPairTest.cpp

   1 //===- llvm/unittest/ADT/PointerIntPairTest.cpp - Unit tests --------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/ADT/PointerIntPair.h"
  10 #include "gtest/gtest.h"
  11 #include <limits>
  12 using namespace llvm;
  13
  14 namespace {
  15
  16 TEST(PointerIntPairTest, GetSet) {
  17   struct S {
  18     int i;
  19   };
  20   S s;
  21
  22   PointerIntPair<S *, 2> Pair(&s, 1U);
  23   EXPECT_EQ(&s, Pair.getPointer());
  24   EXPECT_EQ(1U, Pair.getInt());
  25
  26   Pair.setInt(2);
  27   EXPECT_EQ(&s, Pair.getPointer());
  28   EXPECT_EQ(2U, Pair.getInt());
  29
  30   Pair.setPointer(nullptr);
  31   EXPECT_EQ(nullptr, Pair.getPointer());
  32   EXPECT_EQ(2U, Pair.getInt());
  33
  34   Pair.setPointerAndInt(&s, 3U);
  35   EXPECT_EQ(&s, Pair.getPointer());
  36   EXPECT_EQ(3U, Pair.getInt());
  37
  38   // Make sure that we can perform all of our operations on enum classes.
  39   //
  40   // The concern is that enum classes are only explicitly convertible to
  41   // integers. This means that if we assume in PointerIntPair this, a
  42   // compilation error will result. This group of tests exercises the enum class
  43   // code to make sure that we do not run into such issues in the future.
  44   enum class E : unsigned {
  45     Case1,
  46     Case2,
  47     Case3,
  48   };
  49   PointerIntPair<S *, 2, E> Pair2(&s, E::Case1);
  50   EXPECT_EQ(&s, Pair2.getPointer());
  51   EXPECT_EQ(E::Case1, Pair2.getInt());
  52
  53   Pair2.setInt(E::Case2);
  54   EXPECT_EQ(&s, Pair2.getPointer());
  55   EXPECT_EQ(E::Case2, Pair2.getInt());
  56
  57   Pair2.setPointer(nullptr);
  58   EXPECT_EQ(nullptr, Pair2.getPointer());
  59   EXPECT_EQ(E::Case2, Pair2.getInt());
  60
  61   Pair2.setPointerAndInt(&s, E::Case3);
  62   EXPECT_EQ(&s, Pair2.getPointer());
  63   EXPECT_EQ(E::Case3, Pair2.getInt());
  64
  65   auto [Pointer2, Int2] = Pair2;
  66   EXPECT_EQ(Pair2.getPointer(), Pointer2);
  67   EXPECT_EQ(Pair2.getInt(), Int2);
  68
  69   static_assert(std::is_trivially_copyable_v<PointerIntPair<S *, 2, E>>,
  70                 "trivially copyable");
  71 }
  72
  73 TEST(PointerIntPairTest, DefaultInitialize) {
  74   PointerIntPair<float *, 2> Pair;
  75   EXPECT_EQ(nullptr, Pair.getPointer());
  76   EXPECT_EQ(0U, Pair.getInt());
  77 }
  78
  79 // In real code this would be a word-sized integer limited to 31 bits.
  80 struct Fixnum31 {
  81   uintptr_t Value;
  82 };
  83 struct FixnumPointerTraits {
  84   static inline void *getAsVoidPointer(Fixnum31 Num) {
  85     return reinterpret_cast<void *>(Num.Value << NumLowBitsAvailable);
  86   }
  87   static inline Fixnum31 getFromVoidPointer(void *P) {
  88     // In real code this would assert that the value is in range.
  89     return {reinterpret_cast<uintptr_t>(P) >> NumLowBitsAvailable};
  90   }
  91   static constexpr int NumLowBitsAvailable =
  92       std::numeric_limits<uintptr_t>::digits - 31;
  93 };
  94 TEST(PointerIntPairTest, ManyUnusedBits) {
  95
  96   PointerIntPair<Fixnum31, 1, bool, FixnumPointerTraits> pair;
  97   EXPECT_EQ((uintptr_t)0, pair.getPointer().Value);
  98   EXPECT_FALSE(pair.getInt());
  99
 100   pair.setPointerAndInt({ 0x7FFFFFFF }, true );
 101   EXPECT_EQ((uintptr_t)0x7FFFFFFF, pair.getPointer().Value);
 102   EXPECT_TRUE(pair.getInt());
 103
 104   EXPECT_EQ(FixnumPointerTraits::NumLowBitsAvailable - 1,
 105             (int)PointerLikeTypeTraits<decltype(pair)>::NumLowBitsAvailable);
 106
 107   static_assert(std::is_trivially_copyable_v<
 108                     PointerIntPair<Fixnum31, 1, bool, FixnumPointerTraits>>,
 109                 "trivially copyable");
 110 }
 111
 112 TEST(PointerIntPairTest, TypePunning) {
 113   int I = 0;
 114   int *IntPtr = &I;
 115
 116   int **IntPtrBegin = &IntPtr;
 117   int **IntPtrEnd = IntPtrBegin + 1;
 118
 119   PointerIntPair<int *, 1> Pair;
 120   int **PairAddr = Pair.getAddrOfPointer();
 121
 122   while (IntPtrBegin != IntPtrEnd) {
 123     *PairAddr = *IntPtrBegin;
 124     ++PairAddr;
 125     ++IntPtrBegin;
 126   }
 127   EXPECT_EQ(Pair.getPointer(), IntPtr);
 128 }
 129
 130 } // end anonymous namespace