unittests/ADT/PointerIntPairTest.cpp

   1 //===- llvm/unittest/ADT/PointerIntPairTest.cpp - Unit tests --------------===//
   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/ADT/PointerIntPair.h"
  11 #include "gtest/gtest.h"
  12 #include <limits>
  13 using namespace llvm;
  14
  15 namespace {
  16
  17 TEST(PointerIntPairTest, GetSet) {
  18   struct S {
  19     int i;
  20   };
  21   S s;
  22
  23   PointerIntPair<S *, 2> Pair(&s, 1U);
  24   EXPECT_EQ(&s, Pair.getPointer());
  25   EXPECT_EQ(1U, Pair.getInt());
  26
  27   Pair.setInt(2);
  28   EXPECT_EQ(&s, Pair.getPointer());
  29   EXPECT_EQ(2U, Pair.getInt());
  30
  31   Pair.setPointer(nullptr);
  32   EXPECT_EQ(nullptr, Pair.getPointer());
  33   EXPECT_EQ(2U, Pair.getInt());
  34
  35   Pair.setPointerAndInt(&s, 3U);
  36   EXPECT_EQ(&s, Pair.getPointer());
  37   EXPECT_EQ(3U, Pair.getInt());
  38
  39   // Make sure that we can perform all of our operations on enum classes.
  40   //
  41   // The concern is that enum classes are only explicitly convertible to
  42   // integers. This means that if we assume in PointerIntPair this, a
  43   // compilation error will result. This group of tests exercises the enum class
  44   // code to make sure that we do not run into such issues in the future.
  45   enum class E : unsigned {
  46     Case1,
  47     Case2,
  48     Case3,
  49   };
  50   PointerIntPair<S *, 2, E> Pair2(&s, E::Case1);
  51   EXPECT_EQ(&s, Pair2.getPointer());
  52   EXPECT_EQ(E::Case1, Pair2.getInt());
  53
  54   Pair2.setInt(E::Case2);
  55   EXPECT_EQ(&s, Pair2.getPointer());
  56   EXPECT_EQ(E::Case2, Pair2.getInt());
  57
  58   Pair2.setPointer(nullptr);
  59   EXPECT_EQ(nullptr, Pair2.getPointer());
  60   EXPECT_EQ(E::Case2, Pair2.getInt());
  61
  62   Pair2.setPointerAndInt(&s, E::Case3);
  63   EXPECT_EQ(&s, Pair2.getPointer());
  64   EXPECT_EQ(E::Case3, Pair2.getInt());
  65 }
  66
  67 TEST(PointerIntPairTest, DefaultInitialize) {
  68   PointerIntPair<float *, 2> Pair;
  69   EXPECT_EQ(nullptr, Pair.getPointer());
  70   EXPECT_EQ(0U, Pair.getInt());
  71 }
  72
  73 TEST(PointerIntPairTest, ManyUnusedBits) {
  74   // In real code this would be a word-sized integer limited to 31 bits.
  75   struct Fixnum31 {
  76     uintptr_t Value;
  77   };
  78   class FixnumPointerTraits {
  79   public:
  80     static inline void *getAsVoidPointer(Fixnum31 Num) {
  81       return reinterpret_cast<void *>(Num.Value << NumLowBitsAvailable);
  82     }
  83     static inline Fixnum31 getFromVoidPointer(void *P) {
  84       // In real code this would assert that the value is in range.
  85       return { reinterpret_cast<uintptr_t>(P) >> NumLowBitsAvailable };
  86     }
  87     enum { NumLowBitsAvailable = std::numeric_limits<uintptr_t>::digits - 31 };
  88   };
  89
  90   PointerIntPair<Fixnum31, 1, bool, FixnumPointerTraits> pair;
  91   EXPECT_EQ((uintptr_t)0, pair.getPointer().Value);
  92   EXPECT_FALSE(pair.getInt());
  93
  94   pair.setPointerAndInt({ 0x7FFFFFFF }, true );
  95   EXPECT_EQ((uintptr_t)0x7FFFFFFF, pair.getPointer().Value);
  96   EXPECT_TRUE(pair.getInt());
  97
  98   EXPECT_EQ(FixnumPointerTraits::NumLowBitsAvailable - 1,
  99             PointerLikeTypeTraits<decltype(pair)>::NumLowBitsAvailable);
 100 }
 101
 102 } // end anonymous namespace