unittests/Support/AlignOfTest.cpp

   1 //===- llvm/unittest/Support/AlignOfTest.cpp - Alignment utility 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/Support/AlignOf.h"
  11 #include "llvm/Support/Compiler.h"
  12
  13 #include "gtest/gtest.h"
  14
  15 using namespace llvm;
  16
  17 namespace {
  18
  19 // Define some fixed alignment types to use in these tests.
  20 #if __cplusplus == 201103L || __has_feature(cxx_alignas)
  21 typedef char alignas(1) A1;
  22 typedef char alignas(2) A2;
  23 typedef char alignas(4) A4;
  24 typedef char alignas(8) A8;
  25 #elif defined(__clang__) || defined(__GNUC__)
  26 typedef char A1 __attribute__((aligned(1)));
  27 typedef char A2 __attribute__((aligned(2)));
  28 typedef char A4 __attribute__((aligned(4)));
  29 typedef char A8 __attribute__((aligned(8)));
  30 #elif defined(_MSC_VER)
  31 typedef __declspec(align(1)) char A1;
  32 typedef __declspec(align(2)) char A2;
  33 typedef __declspec(align(4)) char A4;
  34 typedef __declspec(align(8)) char A8;
  35 #else
  36 # error No supported align as directive.
  37 #endif
  38
  39 // Wrap the forced aligned types in structs to hack around compiler bugs.
  40 struct SA1 { A1 a; };
  41 struct SA2 { A2 a; };
  42 struct SA4 { A4 a; };
  43 struct SA8 { A8 a; };
  44
  45 struct S1 {};
  46 struct S2 { char a; };
  47 struct S3 { int x; };
  48 struct S4 { double y; };
  49 struct S5 { A1 a1; A2 a2; A4 a4; A8 a8; };
  50 struct S6 { double f(); };
  51 struct D1 : S1 {};
  52 struct D2 : S6 { float g(); };
  53 struct D3 : S2 {};
  54 struct D4 : S2 { int x; };
  55 struct D5 : S3 { char c; };
  56 struct D6 : S2, S3 {};
  57 struct D7 : S1, S3 {};
  58 struct D8 : S1, D4, D5 { double x[2]; };
  59 struct D9 : S1, D1 { S1 s1; };
  60 struct V1 { virtual ~V1(); };
  61 struct V2 { int x; virtual ~V2(); };
  62 struct V3 : V1 { virtual ~V3(); };
  63 struct V4 : virtual V2 { int y; virtual ~V4(); };
  64 struct V5 : V4, V3 { double z; virtual ~V5(); };
  65 struct V6 : S1 { virtual ~V6(); };
  66 struct V7 : virtual V2, virtual V6 { virtual ~V7(); };
  67 struct V8 : V5, virtual V6, V7 { double zz; virtual ~V8(); };
  68
  69 // Ensure alignment is a compile-time constant.
  70 char LLVM_ATTRIBUTE_UNUSED test_arr1
  71   [AlignOf<char>::Alignment > 0]
  72   [AlignOf<short>::Alignment > 0]
  73   [AlignOf<int>::Alignment > 0]
  74   [AlignOf<long>::Alignment > 0]
  75   [AlignOf<long long>::Alignment > 0]
  76   [AlignOf<float>::Alignment > 0]
  77   [AlignOf<double>::Alignment > 0]
  78   [AlignOf<long double>::Alignment > 0]
  79   [AlignOf<void *>::Alignment > 0]
  80   [AlignOf<int *>::Alignment > 0]
  81   [AlignOf<double (*)(double)>::Alignment > 0]
  82   [AlignOf<double (S6::*)()>::Alignment > 0];
  83 char LLVM_ATTRIBUTE_UNUSED test_arr2
  84   [AlignOf<A1>::Alignment > 0]
  85   [AlignOf<A2>::Alignment > 0]
  86   [AlignOf<A4>::Alignment > 0]
  87   [AlignOf<A8>::Alignment > 0]
  88   [AlignOf<SA1>::Alignment > 0]
  89   [AlignOf<SA2>::Alignment > 0]
  90   [AlignOf<SA4>::Alignment > 0]
  91   [AlignOf<SA8>::Alignment > 0];
  92 char LLVM_ATTRIBUTE_UNUSED test_arr3
  93   [AlignOf<S1>::Alignment > 0]
  94   [AlignOf<S2>::Alignment > 0]
  95   [AlignOf<S3>::Alignment > 0]
  96   [AlignOf<S4>::Alignment > 0]
  97   [AlignOf<S5>::Alignment > 0]
  98   [AlignOf<S6>::Alignment > 0];
  99 char LLVM_ATTRIBUTE_UNUSED test_arr4
 100   [AlignOf<D1>::Alignment > 0]
 101   [AlignOf<D2>::Alignment > 0]
 102   [AlignOf<D3>::Alignment > 0]
 103   [AlignOf<D4>::Alignment > 0]
 104   [AlignOf<D5>::Alignment > 0]
 105   [AlignOf<D6>::Alignment > 0]
 106   [AlignOf<D7>::Alignment > 0]
 107   [AlignOf<D8>::Alignment > 0]
 108   [AlignOf<D9>::Alignment > 0];
 109 char LLVM_ATTRIBUTE_UNUSED test_arr5
 110   [AlignOf<V1>::Alignment > 0]
 111   [AlignOf<V2>::Alignment > 0]
 112   [AlignOf<V3>::Alignment > 0]
 113   [AlignOf<V4>::Alignment > 0]
 114   [AlignOf<V5>::Alignment > 0]
 115   [AlignOf<V6>::Alignment > 0]
 116   [AlignOf<V7>::Alignment > 0]
 117   [AlignOf<V8>::Alignment > 0];
 118
 119 TEST(AlignOfTest, BasicAlignmentInvariants) {
 120   // For a very strange reason, many compilers do not support this. Both Clang
 121   // and GCC fail to align these properly.
 122   EXPECT_EQ(1u, alignOf<A1>());
 123 #if 0
 124   EXPECT_EQ(2u, alignOf<A2>());
 125   EXPECT_EQ(4u, alignOf<A4>());
 126   EXPECT_EQ(8u, alignOf<A8>());
 127 #endif
 128
 129   // But once wrapped in structs, the alignment is correctly managed.
 130   EXPECT_LE(1u, alignOf<SA1>());
 131   EXPECT_LE(2u, alignOf<SA2>());
 132   EXPECT_LE(4u, alignOf<SA4>());
 133   EXPECT_LE(8u, alignOf<SA8>());
 134
 135   EXPECT_EQ(1u, alignOf<char>());
 136   EXPECT_LE(alignOf<char>(),   alignOf<short>());
 137   EXPECT_LE(alignOf<short>(),  alignOf<int>());
 138   EXPECT_LE(alignOf<int>(),    alignOf<long>());
 139   EXPECT_LE(alignOf<long>(),   alignOf<long long>());
 140   EXPECT_LE(alignOf<char>(),   alignOf<float>());
 141   EXPECT_LE(alignOf<float>(),  alignOf<double>());
 142   EXPECT_LE(alignOf<double>(), alignOf<long double>());
 143   EXPECT_LE(alignOf<char>(),   alignOf<void *>());
 144   EXPECT_EQ(alignOf<void *>(), alignOf<int *>());
 145   EXPECT_LE(alignOf<char>(),   alignOf<S1>());
 146   EXPECT_LE(alignOf<S1>(),     alignOf<S2>());
 147   EXPECT_LE(alignOf<S1>(),     alignOf<S3>());
 148   EXPECT_LE(alignOf<S1>(),     alignOf<S4>());
 149   EXPECT_LE(alignOf<S1>(),     alignOf<S5>());
 150   EXPECT_LE(alignOf<S1>(),     alignOf<S6>());
 151   EXPECT_LE(alignOf<S1>(),     alignOf<D1>());
 152   EXPECT_LE(alignOf<S1>(),     alignOf<D2>());
 153   EXPECT_LE(alignOf<S1>(),     alignOf<D3>());
 154   EXPECT_LE(alignOf<S1>(),     alignOf<D4>());
 155   EXPECT_LE(alignOf<S1>(),     alignOf<D5>());
 156   EXPECT_LE(alignOf<S1>(),     alignOf<D6>());
 157   EXPECT_LE(alignOf<S1>(),     alignOf<D7>());
 158   EXPECT_LE(alignOf<S1>(),     alignOf<D8>());
 159   EXPECT_LE(alignOf<S1>(),     alignOf<D9>());
 160   EXPECT_LE(alignOf<S1>(),     alignOf<V1>());
 161   EXPECT_LE(alignOf<V1>(),     alignOf<V2>());
 162   EXPECT_LE(alignOf<V1>(),     alignOf<V3>());
 163   EXPECT_LE(alignOf<V1>(),     alignOf<V4>());
 164   EXPECT_LE(alignOf<V1>(),     alignOf<V5>());
 165   EXPECT_LE(alignOf<V1>(),     alignOf<V6>());
 166   EXPECT_LE(alignOf<V1>(),     alignOf<V7>());
 167   EXPECT_LE(alignOf<V1>(),     alignOf<V8>());
 168 }
 169
 170 TEST(AlignOfTest, BasicAlignedArray) {
 171   // Note: this code exclusively uses the struct-wrapped arbitrarily aligned
 172   // types because of the bugs mentioned above where GCC and Clang both
 173   // disregard the arbitrary alignment specifier until the type is used to
 174   // declare a member of a struct.
 175   EXPECT_LE(1u, alignOf<AlignedCharArray<SA1>::union_type>());
 176   EXPECT_LE(2u, alignOf<AlignedCharArray<SA2>::union_type>());
 177   EXPECT_LE(4u, alignOf<AlignedCharArray<SA4>::union_type>());
 178   EXPECT_LE(8u, alignOf<AlignedCharArray<SA8>::union_type>());
 179
 180   EXPECT_LE(1u, sizeof(AlignedCharArray<SA1>::union_type));
 181   EXPECT_LE(2u, sizeof(AlignedCharArray<SA2>::union_type));
 182   EXPECT_LE(4u, sizeof(AlignedCharArray<SA4>::union_type));
 183   EXPECT_LE(8u, sizeof(AlignedCharArray<SA8>::union_type));
 184
 185   EXPECT_EQ(1u, (alignOf<AlignedCharArray<SA1>::union_type>()));
 186   EXPECT_EQ(2u, (alignOf<AlignedCharArray<SA1, SA2>::union_type>()));
 187   EXPECT_EQ(4u, (alignOf<AlignedCharArray<SA1, SA2, SA4>::union_type>()));
 188   EXPECT_EQ(8u, (alignOf<AlignedCharArray<SA1, SA2, SA4, SA8>::union_type>()));
 189
 190   EXPECT_EQ(1u, sizeof(AlignedCharArray<SA1>::union_type));
 191   EXPECT_EQ(2u, sizeof(AlignedCharArray<SA1, SA2>::union_type));
 192   EXPECT_EQ(4u, sizeof(AlignedCharArray<SA1, SA2, SA4>::union_type));
 193   EXPECT_EQ(8u, sizeof(AlignedCharArray<SA1, SA2, SA4, SA8>::union_type));
 194
 195   EXPECT_EQ(1u, (alignOf<AlignedCharArray<SA1[1]>::union_type>()));
 196   EXPECT_EQ(2u, (alignOf<AlignedCharArray<SA1[2], SA2[1]>::union_type>()));
 197   EXPECT_EQ(4u, (alignOf<AlignedCharArray<SA1[42], SA2[55],
 198                                           SA4[13]>::union_type>()));
 199   EXPECT_EQ(8u, (alignOf<AlignedCharArray<SA1[2], SA2[1],
 200                                           SA4, SA8>::union_type>()));
 201
 202   EXPECT_EQ(1u,  sizeof(AlignedCharArray<SA1[1]>::union_type));
 203   EXPECT_EQ(2u,  sizeof(AlignedCharArray<SA1[2], SA2[1]>::union_type));
 204   EXPECT_EQ(4u,  sizeof(AlignedCharArray<SA1[3], SA2[2], SA4>::union_type));
 205   EXPECT_EQ(16u, sizeof(AlignedCharArray<SA1, SA2[3],
 206                                          SA4[3], SA8>::union_type));
 207
 208   // For other tests we simply assert that the alignment of the union mathes
 209   // that of the fundamental type and hope that we have any weird type
 210   // productions that would trigger bugs.
 211   EXPECT_EQ(alignOf<char>(), alignOf<AlignedCharArray<char>::union_type>());
 212   EXPECT_EQ(alignOf<short>(), alignOf<AlignedCharArray<short>::union_type>());
 213   EXPECT_EQ(alignOf<int>(), alignOf<AlignedCharArray<int>::union_type>());
 214   EXPECT_EQ(alignOf<long>(), alignOf<AlignedCharArray<long>::union_type>());
 215   EXPECT_EQ(alignOf<long long>(),
 216             alignOf<AlignedCharArray<long long>::union_type>());
 217   EXPECT_EQ(alignOf<float>(), alignOf<AlignedCharArray<float>::union_type>());
 218   EXPECT_EQ(alignOf<double>(), alignOf<AlignedCharArray<double>::union_type>());
 219   EXPECT_EQ(alignOf<long double>(),
 220             alignOf<AlignedCharArray<long double>::union_type>());
 221   EXPECT_EQ(alignOf<void *>(), alignOf<AlignedCharArray<void *>::union_type>());
 222   EXPECT_EQ(alignOf<int *>(), alignOf<AlignedCharArray<int *>::union_type>());
 223   EXPECT_EQ(alignOf<double (*)(double)>(),
 224             alignOf<AlignedCharArray<double (*)(double)>::union_type>());
 225   EXPECT_EQ(alignOf<double (S6::*)()>(),
 226             alignOf<AlignedCharArray<double (S6::*)()>::union_type>());
 227   EXPECT_EQ(alignOf<S1>(), alignOf<AlignedCharArray<S1>::union_type>());
 228   EXPECT_EQ(alignOf<S2>(), alignOf<AlignedCharArray<S2>::union_type>());
 229   EXPECT_EQ(alignOf<S3>(), alignOf<AlignedCharArray<S3>::union_type>());
 230   EXPECT_EQ(alignOf<S4>(), alignOf<AlignedCharArray<S4>::union_type>());
 231   EXPECT_EQ(alignOf<S5>(), alignOf<AlignedCharArray<S5>::union_type>());
 232   EXPECT_EQ(alignOf<S6>(), alignOf<AlignedCharArray<S6>::union_type>());
 233   EXPECT_EQ(alignOf<D1>(), alignOf<AlignedCharArray<D1>::union_type>());
 234   EXPECT_EQ(alignOf<D2>(), alignOf<AlignedCharArray<D2>::union_type>());
 235   EXPECT_EQ(alignOf<D3>(), alignOf<AlignedCharArray<D3>::union_type>());
 236   EXPECT_EQ(alignOf<D4>(), alignOf<AlignedCharArray<D4>::union_type>());
 237   EXPECT_EQ(alignOf<D5>(), alignOf<AlignedCharArray<D5>::union_type>());
 238   EXPECT_EQ(alignOf<D6>(), alignOf<AlignedCharArray<D6>::union_type>());
 239   EXPECT_EQ(alignOf<D7>(), alignOf<AlignedCharArray<D7>::union_type>());
 240   EXPECT_EQ(alignOf<D8>(), alignOf<AlignedCharArray<D8>::union_type>());
 241   EXPECT_EQ(alignOf<D9>(), alignOf<AlignedCharArray<D9>::union_type>());
 242   EXPECT_EQ(alignOf<V1>(), alignOf<AlignedCharArray<V1>::union_type>());
 243   EXPECT_EQ(alignOf<V2>(), alignOf<AlignedCharArray<V2>::union_type>());
 244   EXPECT_EQ(alignOf<V3>(), alignOf<AlignedCharArray<V3>::union_type>());
 245   EXPECT_EQ(alignOf<V4>(), alignOf<AlignedCharArray<V4>::union_type>());
 246   EXPECT_EQ(alignOf<V5>(), alignOf<AlignedCharArray<V5>::union_type>());
 247   EXPECT_EQ(alignOf<V6>(), alignOf<AlignedCharArray<V6>::union_type>());
 248   EXPECT_EQ(alignOf<V7>(), alignOf<AlignedCharArray<V7>::union_type>());
 249   EXPECT_EQ(alignOf<V8>(), alignOf<AlignedCharArray<V8>::union_type>());
 250 }
 251
 252 }