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      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 "gtest/gtest.h"
     11 #include "llvm/ADT/PointerIntPair.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
    103