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 // Disable warnings about questionable type definitions.
  20 // We're testing that even questionable types work with the alignment utilities.
  21 #ifdef _MSC_VER
  22 #pragma warning(disable:4584)
  23 #endif
  24
  25 // Define some fixed alignment types to use in these tests.
  26 #if __cplusplus == 201103L || __has_feature(cxx_alignas)
  27 typedef char alignas(1) A1;
  28 typedef char alignas(2) A2;
  29 typedef char alignas(4) A4;
  30 typedef char alignas(8) A8;
  31 #elif defined(__clang__) || defined(__GNUC__)
  32 typedef char A1 __attribute__((aligned(1)));
  33 typedef char A2 __attribute__((aligned(2)));
  34 typedef char A4 __attribute__((aligned(4)));
  35 typedef char A8 __attribute__((aligned(8)));
  36 #elif defined(_MSC_VER)
  37 typedef __declspec(align(1)) char A1;
  38 typedef __declspec(align(2)) char A2;
  39 typedef __declspec(align(4)) char A4;
  40 typedef __declspec(align(8)) char A8;
  41 #else
  42 # error No supported align as directive.
  43 #endif
  44
  45 // Wrap the forced aligned types in structs to hack around compiler bugs.
  46 struct SA1 { A1 a; };
  47 struct SA2 { A2 a; };
  48 struct SA4 { A4 a; };
  49 struct SA8 { A8 a; };
  50
  51 struct S1 {};
  52 struct S2 { char a; };
  53 struct S3 { int x; };
  54 struct S4 { double y; };
  55 struct S5 { A1 a1; A2 a2; A4 a4; A8 a8; };
  56 struct S6 { double f(); };
  57 struct D1 : S1 {};
  58 struct D2 : S6 { float g(); };
  59 struct D3 : S2 {};
  60 struct D4 : S2 { int x; };
  61 struct D5 : S3 { char c; };
  62 struct D6 : S2, S3 {};
  63 struct D7 : S1, S3 {};
  64 struct D8 : S1, D4, D5 { double x[2]; };
  65 struct D9 : S1, D1 { S1 s1; };
  66 struct V1 { virtual ~V1(); };
  67 struct V2 { int x; virtual ~V2(); };
  68 struct V3 : V1 { virtual ~V3(); };
  69 struct V4 : virtual V2 { int y; virtual ~V4(); };
  70 struct V5 : V4, V3 { double z; virtual ~V5(); };
  71 struct V6 : S1 { virtual ~V6(); };
  72 struct V7 : virtual V2, virtual V6 { virtual ~V7(); };
  73 struct V8 : V5, virtual V6, V7 { double zz; virtual ~V8(); };
  74
  75 // Ensure alignment is a compile-time constant.
  76 char LLVM_ATTRIBUTE_UNUSED test_arr1
  77   [AlignOf<char>::Alignment > 0]
  78   [AlignOf<short>::Alignment > 0]
  79   [AlignOf<int>::Alignment > 0]
  80   [AlignOf<long>::Alignment > 0]
  81   [AlignOf<long long>::Alignment > 0]
  82   [AlignOf<float>::Alignment > 0]
  83   [AlignOf<double>::Alignment > 0]
  84   [AlignOf<long double>::Alignment > 0]
  85   [AlignOf<void *>::Alignment > 0]
  86   [AlignOf<int *>::Alignment > 0]
  87   [AlignOf<double (*)(double)>::Alignment > 0]
  88   [AlignOf<double (S6::*)()>::Alignment > 0];
  89 char LLVM_ATTRIBUTE_UNUSED test_arr2
  90   [AlignOf<A1>::Alignment > 0]
  91   [AlignOf<A2>::Alignment > 0]
  92   [AlignOf<A4>::Alignment > 0]
  93   [AlignOf<A8>::Alignment > 0]
  94   [AlignOf<SA1>::Alignment > 0]
  95   [AlignOf<SA2>::Alignment > 0]
  96   [AlignOf<SA4>::Alignment > 0]
  97   [AlignOf<SA8>::Alignment > 0];
  98 char LLVM_ATTRIBUTE_UNUSED test_arr3
  99   [AlignOf<S1>::Alignment > 0]
 100   [AlignOf<S2>::Alignment > 0]
 101   [AlignOf<S3>::Alignment > 0]
 102   [AlignOf<S4>::Alignment > 0]
 103   [AlignOf<S5>::Alignment > 0]
 104   [AlignOf<S6>::Alignment > 0];
 105 char LLVM_ATTRIBUTE_UNUSED test_arr4
 106   [AlignOf<D1>::Alignment > 0]
 107   [AlignOf<D2>::Alignment > 0]
 108   [AlignOf<D3>::Alignment > 0]
 109   [AlignOf<D4>::Alignment > 0]
 110   [AlignOf<D5>::Alignment > 0]
 111   [AlignOf<D6>::Alignment > 0]
 112   [AlignOf<D7>::Alignment > 0]
 113   [AlignOf<D8>::Alignment > 0]
 114   [AlignOf<D9>::Alignment > 0];
 115 char LLVM_ATTRIBUTE_UNUSED test_arr5
 116   [AlignOf<V1>::Alignment > 0]
 117   [AlignOf<V2>::Alignment > 0]
 118   [AlignOf<V3>::Alignment > 0]
 119   [AlignOf<V4>::Alignment > 0]
 120   [AlignOf<V5>::Alignment > 0]
 121   [AlignOf<V6>::Alignment > 0]
 122   [AlignOf<V7>::Alignment > 0]
 123   [AlignOf<V8>::Alignment > 0];
 124
 125 TEST(AlignOfTest, BasicAlignmentInvariants) {
 126   // For a very strange reason, many compilers do not support this. Both Clang
 127   // and GCC fail to align these properly.
 128   EXPECT_EQ(1u, alignOf<A1>());
 129 #if 0
 130   EXPECT_EQ(2u, alignOf<A2>());
 131   EXPECT_EQ(4u, alignOf<A4>());
 132   EXPECT_EQ(8u, alignOf<A8>());
 133 #endif
 134
 135   // But once wrapped in structs, the alignment is correctly managed.
 136   EXPECT_LE(1u, alignOf<SA1>());
 137   EXPECT_LE(2u, alignOf<SA2>());
 138   EXPECT_LE(4u, alignOf<SA4>());
 139   EXPECT_LE(8u, alignOf<SA8>());
 140
 141   EXPECT_EQ(1u, alignOf<char>());
 142   EXPECT_LE(alignOf<char>(),   alignOf<short>());
 143   EXPECT_LE(alignOf<short>(),  alignOf<int>());
 144   EXPECT_LE(alignOf<int>(),    alignOf<long>());
 145   EXPECT_LE(alignOf<long>(),   alignOf<long long>());
 146   EXPECT_LE(alignOf<char>(),   alignOf<float>());
 147   EXPECT_LE(alignOf<float>(),  alignOf<double>());
 148   EXPECT_LE(alignOf<char>(),   alignOf<long double>());
 149   EXPECT_LE(alignOf<char>(),   alignOf<void *>());
 150   EXPECT_EQ(alignOf<void *>(), alignOf<int *>());
 151   EXPECT_LE(alignOf<char>(),   alignOf<S1>());
 152   EXPECT_LE(alignOf<S1>(),     alignOf<S2>());
 153   EXPECT_LE(alignOf<S1>(),     alignOf<S3>());
 154   EXPECT_LE(alignOf<S1>(),     alignOf<S4>());
 155   EXPECT_LE(alignOf<S1>(),     alignOf<S5>());
 156   EXPECT_LE(alignOf<S1>(),     alignOf<S6>());
 157   EXPECT_LE(alignOf<S1>(),     alignOf<D1>());
 158   EXPECT_LE(alignOf<S1>(),     alignOf<D2>());
 159   EXPECT_LE(alignOf<S1>(),     alignOf<D3>());
 160   EXPECT_LE(alignOf<S1>(),     alignOf<D4>());
 161   EXPECT_LE(alignOf<S1>(),     alignOf<D5>());
 162   EXPECT_LE(alignOf<S1>(),     alignOf<D6>());
 163   EXPECT_LE(alignOf<S1>(),     alignOf<D7>());
 164   EXPECT_LE(alignOf<S1>(),     alignOf<D8>());
 165   EXPECT_LE(alignOf<S1>(),     alignOf<D9>());
 166   EXPECT_LE(alignOf<S1>(),     alignOf<V1>());
 167   EXPECT_LE(alignOf<V1>(),     alignOf<V2>());
 168   EXPECT_LE(alignOf<V1>(),     alignOf<V3>());
 169   EXPECT_LE(alignOf<V1>(),     alignOf<V4>());
 170   EXPECT_LE(alignOf<V1>(),     alignOf<V5>());
 171   EXPECT_LE(alignOf<V1>(),     alignOf<V6>());
 172   EXPECT_LE(alignOf<V1>(),     alignOf<V7>());
 173   EXPECT_LE(alignOf<V1>(),     alignOf<V8>());
 174 }
 175
 176 TEST(AlignOfTest, BasicAlignedArray) {
 177   // Note: this code exclusively uses the struct-wrapped arbitrarily aligned
 178   // types because of the bugs mentioned above where GCC and Clang both
 179   // disregard the arbitrary alignment specifier until the type is used to
 180   // declare a member of a struct.
 181   EXPECT_LE(1u, alignOf<AlignedCharArray<SA1>::union_type>());
 182   EXPECT_LE(2u, alignOf<AlignedCharArray<SA2>::union_type>());
 183   EXPECT_LE(4u, alignOf<AlignedCharArray<SA4>::union_type>());
 184   EXPECT_LE(8u, alignOf<AlignedCharArray<SA8>::union_type>());
 185
 186   EXPECT_LE(1u, sizeof(AlignedCharArray<SA1>::union_type));
 187   EXPECT_LE(2u, sizeof(AlignedCharArray<SA2>::union_type));
 188   EXPECT_LE(4u, sizeof(AlignedCharArray<SA4>::union_type));
 189   EXPECT_LE(8u, sizeof(AlignedCharArray<SA8>::union_type));
 190
 191   EXPECT_EQ(1u, (alignOf<AlignedCharArray<SA1>::union_type>()));
 192   EXPECT_EQ(2u, (alignOf<AlignedCharArray<SA1, SA2>::union_type>()));
 193   EXPECT_EQ(4u, (alignOf<AlignedCharArray<SA1, SA2, SA4>::union_type>()));
 194   EXPECT_EQ(8u, (alignOf<AlignedCharArray<SA1, SA2, SA4, SA8>::union_type>()));
 195
 196   EXPECT_EQ(1u, sizeof(AlignedCharArray<SA1>::union_type));
 197   EXPECT_EQ(2u, sizeof(AlignedCharArray<SA1, SA2>::union_type));
 198   EXPECT_EQ(4u, sizeof(AlignedCharArray<SA1, SA2, SA4>::union_type));
 199   EXPECT_EQ(8u, sizeof(AlignedCharArray<SA1, SA2, SA4, SA8>::union_type));
 200
 201   EXPECT_EQ(1u, (alignOf<AlignedCharArray<SA1[1]>::union_type>()));
 202   EXPECT_EQ(2u, (alignOf<AlignedCharArray<SA1[2], SA2[1]>::union_type>()));
 203   EXPECT_EQ(4u, (alignOf<AlignedCharArray<SA1[42], SA2[55],
 204                                           SA4[13]>::union_type>()));
 205   EXPECT_EQ(8u, (alignOf<AlignedCharArray<SA1[2], SA2[1],
 206                                           SA4, SA8>::union_type>()));
 207
 208   EXPECT_EQ(1u,  sizeof(AlignedCharArray<SA1[1]>::union_type));
 209   EXPECT_EQ(2u,  sizeof(AlignedCharArray<SA1[2], SA2[1]>::union_type));
 210   EXPECT_EQ(4u,  sizeof(AlignedCharArray<SA1[3], SA2[2], SA4>::union_type));
 211   EXPECT_EQ(16u, sizeof(AlignedCharArray<SA1, SA2[3],
 212                                          SA4[3], SA8>::union_type));
 213
 214   // For other tests we simply assert that the alignment of the union mathes
 215   // that of the fundamental type and hope that we have any weird type
 216   // productions that would trigger bugs.
 217   EXPECT_EQ(alignOf<char>(), alignOf<AlignedCharArray<char>::union_type>());
 218   EXPECT_EQ(alignOf<short>(), alignOf<AlignedCharArray<short>::union_type>());
 219   EXPECT_EQ(alignOf<int>(), alignOf<AlignedCharArray<int>::union_type>());
 220   EXPECT_EQ(alignOf<long>(), alignOf<AlignedCharArray<long>::union_type>());
 221   EXPECT_EQ(alignOf<long long>(),
 222             alignOf<AlignedCharArray<long long>::union_type>());
 223   EXPECT_EQ(alignOf<float>(), alignOf<AlignedCharArray<float>::union_type>());
 224   EXPECT_EQ(alignOf<double>(), alignOf<AlignedCharArray<double>::union_type>());
 225   EXPECT_EQ(alignOf<long double>(),
 226             alignOf<AlignedCharArray<long double>::union_type>());
 227   EXPECT_EQ(alignOf<void *>(), alignOf<AlignedCharArray<void *>::union_type>());
 228   EXPECT_EQ(alignOf<int *>(), alignOf<AlignedCharArray<int *>::union_type>());
 229   EXPECT_EQ(alignOf<double (*)(double)>(),
 230             alignOf<AlignedCharArray<double (*)(double)>::union_type>());
 231   EXPECT_EQ(alignOf<double (S6::*)()>(),
 232             alignOf<AlignedCharArray<double (S6::*)()>::union_type>());
 233   EXPECT_EQ(alignOf<S1>(), alignOf<AlignedCharArray<S1>::union_type>());
 234   EXPECT_EQ(alignOf<S2>(), alignOf<AlignedCharArray<S2>::union_type>());
 235   EXPECT_EQ(alignOf<S3>(), alignOf<AlignedCharArray<S3>::union_type>());
 236   EXPECT_EQ(alignOf<S4>(), alignOf<AlignedCharArray<S4>::union_type>());
 237   EXPECT_EQ(alignOf<S5>(), alignOf<AlignedCharArray<S5>::union_type>());
 238   EXPECT_EQ(alignOf<S6>(), alignOf<AlignedCharArray<S6>::union_type>());
 239   EXPECT_EQ(alignOf<D1>(), alignOf<AlignedCharArray<D1>::union_type>());
 240   EXPECT_EQ(alignOf<D2>(), alignOf<AlignedCharArray<D2>::union_type>());
 241   EXPECT_EQ(alignOf<D3>(), alignOf<AlignedCharArray<D3>::union_type>());
 242   EXPECT_EQ(alignOf<D4>(), alignOf<AlignedCharArray<D4>::union_type>());
 243   EXPECT_EQ(alignOf<D5>(), alignOf<AlignedCharArray<D5>::union_type>());
 244   EXPECT_EQ(alignOf<D6>(), alignOf<AlignedCharArray<D6>::union_type>());
 245   EXPECT_EQ(alignOf<D7>(), alignOf<AlignedCharArray<D7>::union_type>());
 246   EXPECT_EQ(alignOf<D8>(), alignOf<AlignedCharArray<D8>::union_type>());
 247   EXPECT_EQ(alignOf<D9>(), alignOf<AlignedCharArray<D9>::union_type>());
 248   EXPECT_EQ(alignOf<V1>(), alignOf<AlignedCharArray<V1>::union_type>());
 249   EXPECT_EQ(alignOf<V2>(), alignOf<AlignedCharArray<V2>::union_type>());
 250   EXPECT_EQ(alignOf<V3>(), alignOf<AlignedCharArray<V3>::union_type>());
 251   EXPECT_EQ(alignOf<V4>(), alignOf<AlignedCharArray<V4>::union_type>());
 252   EXPECT_EQ(alignOf<V5>(), alignOf<AlignedCharArray<V5>::union_type>());
 253   EXPECT_EQ(alignOf<V6>(), alignOf<AlignedCharArray<V6>::union_type>());
 254   EXPECT_EQ(alignOf<V7>(), alignOf<AlignedCharArray<V7>::union_type>());
 255
 256   // Some versions of MSVC get this wrong somewhat disturbingly. The failure
 257   // appears to be benign: alignOf<V8>() produces a preposterous value: 12
 258 #ifndef _MSC_VER
 259   EXPECT_EQ(alignOf<V8>(), alignOf<AlignedCharArray<V8>::union_type>());
 260 #endif
 261
 262   EXPECT_EQ(sizeof(char), sizeof(AlignedCharArray<char>::union_type));
 263   EXPECT_EQ(sizeof(char[1]), sizeof(AlignedCharArray<char[1]>::union_type));
 264   EXPECT_EQ(sizeof(char[2]), sizeof(AlignedCharArray<char[2]>::union_type));
 265   EXPECT_EQ(sizeof(char[3]), sizeof(AlignedCharArray<char[3]>::union_type));
 266   EXPECT_EQ(sizeof(char[4]), sizeof(AlignedCharArray<char[4]>::union_type));
 267   EXPECT_EQ(sizeof(char[5]), sizeof(AlignedCharArray<char[5]>::union_type));
 268   EXPECT_EQ(sizeof(char[8]), sizeof(AlignedCharArray<char[8]>::union_type));
 269   EXPECT_EQ(sizeof(char[13]), sizeof(AlignedCharArray<char[13]>::union_type));
 270   EXPECT_EQ(sizeof(char[16]), sizeof(AlignedCharArray<char[16]>::union_type));
 271   EXPECT_EQ(sizeof(char[21]), sizeof(AlignedCharArray<char[21]>::union_type));
 272   EXPECT_EQ(sizeof(char[32]), sizeof(AlignedCharArray<char[32]>::union_type));
 273   EXPECT_EQ(sizeof(short), sizeof(AlignedCharArray<short>::union_type));
 274   EXPECT_EQ(sizeof(int), sizeof(AlignedCharArray<int>::union_type));
 275   EXPECT_EQ(sizeof(long), sizeof(AlignedCharArray<long>::union_type));
 276   EXPECT_EQ(sizeof(long long),
 277             sizeof(AlignedCharArray<long long>::union_type));
 278   EXPECT_EQ(sizeof(float), sizeof(AlignedCharArray<float>::union_type));
 279   EXPECT_EQ(sizeof(double), sizeof(AlignedCharArray<double>::union_type));
 280   EXPECT_EQ(sizeof(long double),
 281             sizeof(AlignedCharArray<long double>::union_type));
 282   EXPECT_EQ(sizeof(void *), sizeof(AlignedCharArray<void *>::union_type));
 283   EXPECT_EQ(sizeof(int *), sizeof(AlignedCharArray<int *>::union_type));
 284   EXPECT_EQ(sizeof(double (*)(double)),
 285             sizeof(AlignedCharArray<double (*)(double)>::union_type));
 286   EXPECT_EQ(sizeof(double (S6::*)()),
 287             sizeof(AlignedCharArray<double (S6::*)()>::union_type));
 288   EXPECT_EQ(sizeof(S1), sizeof(AlignedCharArray<S1>::union_type));
 289   EXPECT_EQ(sizeof(S2), sizeof(AlignedCharArray<S2>::union_type));
 290   EXPECT_EQ(sizeof(S3), sizeof(AlignedCharArray<S3>::union_type));
 291   EXPECT_EQ(sizeof(S4), sizeof(AlignedCharArray<S4>::union_type));
 292   EXPECT_EQ(sizeof(S5), sizeof(AlignedCharArray<S5>::union_type));
 293   EXPECT_EQ(sizeof(S6), sizeof(AlignedCharArray<S6>::union_type));
 294   EXPECT_EQ(sizeof(D1), sizeof(AlignedCharArray<D1>::union_type));
 295   EXPECT_EQ(sizeof(D2), sizeof(AlignedCharArray<D2>::union_type));
 296   EXPECT_EQ(sizeof(D3), sizeof(AlignedCharArray<D3>::union_type));
 297   EXPECT_EQ(sizeof(D4), sizeof(AlignedCharArray<D4>::union_type));
 298   EXPECT_EQ(sizeof(D5), sizeof(AlignedCharArray<D5>::union_type));
 299   EXPECT_EQ(sizeof(D6), sizeof(AlignedCharArray<D6>::union_type));
 300   EXPECT_EQ(sizeof(D7), sizeof(AlignedCharArray<D7>::union_type));
 301   EXPECT_EQ(sizeof(D8), sizeof(AlignedCharArray<D8>::union_type));
 302   EXPECT_EQ(sizeof(D9), sizeof(AlignedCharArray<D9>::union_type));
 303   EXPECT_EQ(sizeof(D9[1]), sizeof(AlignedCharArray<D9[1]>::union_type));
 304   EXPECT_EQ(sizeof(D9[2]), sizeof(AlignedCharArray<D9[2]>::union_type));
 305   EXPECT_EQ(sizeof(D9[3]), sizeof(AlignedCharArray<D9[3]>::union_type));
 306   EXPECT_EQ(sizeof(D9[4]), sizeof(AlignedCharArray<D9[4]>::union_type));
 307   EXPECT_EQ(sizeof(D9[5]), sizeof(AlignedCharArray<D9[5]>::union_type));
 308   EXPECT_EQ(sizeof(D9[8]), sizeof(AlignedCharArray<D9[8]>::union_type));
 309   EXPECT_EQ(sizeof(D9[13]), sizeof(AlignedCharArray<D9[13]>::union_type));
 310   EXPECT_EQ(sizeof(D9[16]), sizeof(AlignedCharArray<D9[16]>::union_type));
 311   EXPECT_EQ(sizeof(D9[21]), sizeof(AlignedCharArray<D9[21]>::union_type));
 312   EXPECT_EQ(sizeof(D9[32]), sizeof(AlignedCharArray<D9[32]>::union_type));
 313   EXPECT_EQ(sizeof(V1), sizeof(AlignedCharArray<V1>::union_type));
 314   EXPECT_EQ(sizeof(V2), sizeof(AlignedCharArray<V2>::union_type));
 315   EXPECT_EQ(sizeof(V3), sizeof(AlignedCharArray<V3>::union_type));
 316   EXPECT_EQ(sizeof(V4), sizeof(AlignedCharArray<V4>::union_type));
 317   EXPECT_EQ(sizeof(V5), sizeof(AlignedCharArray<V5>::union_type));
 318   EXPECT_EQ(sizeof(V6), sizeof(AlignedCharArray<V6>::union_type));
 319   EXPECT_EQ(sizeof(V7), sizeof(AlignedCharArray<V7>::union_type));
 320
 321   // Some versions of MSVC also get this wrong. The failure again appears to be
 322   // benign: sizeof(V8) is only 52 bytes, but our array reserves 56.
 323 #ifndef _MSC_VER
 324   EXPECT_EQ(sizeof(V8), sizeof(AlignedCharArray<V8>::union_type));
 325 #endif
 326 }
 327
 328 }