diff options
| -rw-r--r-- | include/llvm/Support/AlignOf.h | 90 | ||||
| -rw-r--r-- | unittests/CMakeLists.txt | 1 | ||||
| -rw-r--r-- | unittests/Support/AlignOfTest.cpp | 248 |
3 files changed, 339 insertions, 0 deletions
diff --git a/include/llvm/Support/AlignOf.h b/include/llvm/Support/AlignOf.h index cebfa79..b63e75f 100644 --- a/include/llvm/Support/AlignOf.h +++ b/include/llvm/Support/AlignOf.h @@ -15,6 +15,9 @@ #ifndef LLVM_SUPPORT_ALIGNOF_H #define LLVM_SUPPORT_ALIGNOF_H +#include "llvm/Support/Compiler.h" +#include <cstddef> + namespace llvm { template <typename T> @@ -56,5 +59,92 @@ struct AlignOf { template <typename T> static inline unsigned alignOf() { return AlignOf<T>::Alignment; } + +/// \brief Helper for building an aligned character array type. +/// +/// This template is used to explicitly build up a collection of aligned +/// character types. We have to build these up using a macro and explicit +/// specialization to cope with old versions of MSVC and GCC where only an +/// integer literal can be used to specify an alignment constraint. Once built +/// up here, we can then begin to indirect between these using normal C++ +/// template parameters. +template <size_t Alignment> struct AlignedCharArrayImpl {}; +template <> struct AlignedCharArrayImpl<0> { + typedef char type; +}; +#if __cplusplus == 201103L || __has_feature(cxx_alignas) +#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \ + template <> struct AlignedCharArrayImpl<x> { \ + typedef char alignas(x) type; \ + } +#elif defined(__clang__) || defined(__GNUC__) +#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \ + template <> struct AlignedCharArrayImpl<x> { \ + typedef char type __attribute__((aligned(x))); \ + } +#elif defined(_MSC_VER) +#define LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(x) \ + template <> struct AlignedCharArrayImpl<x> { \ + typedef __declspec(align(x)) char type; \ + } +#else +# error No supported align as directive. +#endif + +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(1); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(2); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(4); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(8); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(16); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(32); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(64); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(128); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(512); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(1024); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(2048); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(4096); +LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT(8192); +// Any larger and MSVC complains. +#undef LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT + +/// \brief This class template exposes a typedef for type containing a suitable +/// aligned character array to hold elements of any of up to four types. +/// +/// These types may be arrays, structs, or any other types. The goal is to +/// produce a union type containing a character array which, when used, forms +/// storage suitable to placement new any of these types over. Support for more +/// than four types can be added at the cost of more boiler plate. +template <typename T1, + typename T2 = char, typename T3 = char, typename T4 = char> +class AlignedCharArray { + class AlignerImpl { + T1 t1; T2 t2; T3 t3; T4 t4; + + AlignerImpl(); // Never defined or instantiated. + }; + union SizerImpl { + char arr1[sizeof(T1)], arr2[sizeof(T2)], arr3[sizeof(T3)], arr4[sizeof(T4)]; + }; + +public: + // Sadly, Clang and GCC both fail to align a character array properly even + // with an explicit alignment attribute. To work around this, we union + // the character array that will actually be used with a struct that contains + // a single aligned character member. Tests seem to indicate that both Clang + // and GCC will properly register the alignment of a struct containing an + // aligned member, and this alignment should carry over to the character + // array in the union. + union union_type { + // This is the only member of the union which should be used by clients: + char buffer[sizeof(SizerImpl)]; + + // This member of the union only exists to force the alignment. + struct { + typename llvm::AlignedCharArrayImpl<AlignOf<AlignerImpl>::Alignment>::type + nonce_inner_member; + } nonce_member; + }; +}; + } // end namespace llvm #endif diff --git a/unittests/CMakeLists.txt b/unittests/CMakeLists.txt index 11a5a5a..bfb05ed 100644 --- a/unittests/CMakeLists.txt +++ b/unittests/CMakeLists.txt @@ -166,6 +166,7 @@ set(LLVM_LINK_COMPONENTS ) add_llvm_unittest(Support + Support/AlignOfTest.cpp Support/AllocatorTest.cpp Support/Casting.cpp Support/CommandLineTest.cpp diff --git a/unittests/Support/AlignOfTest.cpp b/unittests/Support/AlignOfTest.cpp new file mode 100644 index 0000000..b86f2bd --- /dev/null +++ b/unittests/Support/AlignOfTest.cpp @@ -0,0 +1,248 @@ +//===- llvm/unittest/Support/AlignOfTest.cpp - Alignment utility tests ----===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Support/AlignOf.h" +#include "llvm/Support/Compiler.h" + +#include "gtest/gtest.h" + +using namespace llvm; + +namespace { + +// Define some fixed alignment types to use in these tests. +#if __cplusplus == 201103L || __has_feature(cxx_alignas) +typedef char alignas(1) A1; +typedef char alignas(2) A2; +typedef char alignas(4) A4; +typedef char alignas(8) A8; +#elif defined(__clang__) || defined(__GNUC__) +typedef char A1 __attribute__((aligned(1))); +typedef char A2 __attribute__((aligned(2))); +typedef char A4 __attribute__((aligned(4))); +typedef char A8 __attribute__((aligned(8))); +#elif defined(_MSC_VER) +typedef __declspec(align(1)) char A1; +typedef __declspec(align(2)) char A2; +typedef __declspec(align(4)) char A4; +typedef __declspec(align(8)) char A8; +#else +# error No supported align as directive. +#endif + +// Wrap the forced aligned types in structs to hack around compiler bugs. +struct SA1 { A1 a; }; +struct SA2 { A2 a; }; +struct SA4 { A4 a; }; +struct SA8 { A8 a; }; + +struct S1 {}; +struct S2 { char a; }; +struct S3 { int x; }; +struct S4 { double y; }; +struct S5 { A1 a1; A2 a2; A4 a4; A8 a8; }; +struct S6 { double f(); }; +struct D1 : S1 {}; +struct D2 : S6 { float g(); }; +struct D3 : S2 {}; +struct D4 : S2 { int x; }; +struct D5 : S3 { char c; }; +struct D6 : S2, S3 {}; +struct D7 : S1, S3 {}; +struct D8 : S1, D4, D5 { double x[2]; }; +struct D9 : S1, D1 { S1 s1; }; +struct V1 { virtual ~V1(); }; +struct V2 { int x; virtual ~V2(); }; +struct V3 : V1 { virtual ~V3(); }; +struct V4 : virtual V2 { int y; virtual ~V4(); }; +struct V5 : V4, V3 { double z; virtual ~V5(); }; +struct V6 : S1 { virtual ~V6(); }; +struct V7 : virtual V2, virtual V6 { virtual ~V7(); }; +struct V8 : V5, virtual V6, V7 { double zz; virtual ~V8(); }; + +// Ensure alignment is a compile-time constant. +char LLVM_ATTRIBUTE_UNUSED test_arr + [AlignOf<char>::Alignment] + [AlignOf<short>::Alignment] + [AlignOf<int>::Alignment] + [AlignOf<long>::Alignment] + [AlignOf<long long>::Alignment] + [AlignOf<float>::Alignment] + [AlignOf<double>::Alignment] + [AlignOf<long double>::Alignment] + [AlignOf<void *>::Alignment] + [AlignOf<int *>::Alignment] + [AlignOf<double (*)(double)>::Alignment] + [AlignOf<double (S6::*)()>::Alignment] + [AlignOf<A1>::Alignment] + [AlignOf<A2>::Alignment] + [AlignOf<A4>::Alignment] + [AlignOf<A8>::Alignment] + [AlignOf<SA1>::Alignment] + [AlignOf<SA2>::Alignment] + [AlignOf<SA4>::Alignment] + [AlignOf<SA8>::Alignment] + [AlignOf<S1>::Alignment] + [AlignOf<S2>::Alignment] + [AlignOf<S3>::Alignment] + [AlignOf<S4>::Alignment] + [AlignOf<S5>::Alignment] + [AlignOf<S6>::Alignment] + [AlignOf<D1>::Alignment] + [AlignOf<D2>::Alignment] + [AlignOf<D3>::Alignment] + [AlignOf<D4>::Alignment] + [AlignOf<D5>::Alignment] + [AlignOf<D6>::Alignment] + [AlignOf<D7>::Alignment] + [AlignOf<D8>::Alignment] + [AlignOf<D9>::Alignment] + [AlignOf<V1>::Alignment] + [AlignOf<V2>::Alignment] + [AlignOf<V3>::Alignment] + [AlignOf<V4>::Alignment] + [AlignOf<V5>::Alignment] + [AlignOf<V6>::Alignment] + [AlignOf<V7>::Alignment] + [AlignOf<V8>::Alignment]; + +TEST(AlignOfTest, BasicAlignmentInvariants) { + // For a very strange reason, many compilers do not support this. Both Clang + // and GCC fail to align these properly. + EXPECT_EQ(1u, alignOf<A1>()); +#if 0 + EXPECT_EQ(2u, alignOf<A2>()); + EXPECT_EQ(4u, alignOf<A4>()); + EXPECT_EQ(8u, alignOf<A8>()); +#endif + + // But once wrapped in structs, the alignment is correctly managed. + EXPECT_LE(1u, alignOf<SA1>()); + EXPECT_LE(2u, alignOf<SA2>()); + EXPECT_LE(4u, alignOf<SA4>()); + EXPECT_LE(8u, alignOf<SA8>()); + + EXPECT_EQ(1u, alignOf<char>()); + EXPECT_LE(alignOf<char>(), alignOf<short>()); + EXPECT_LE(alignOf<short>(), alignOf<int>()); + EXPECT_LE(alignOf<int>(), alignOf<long>()); + EXPECT_LE(alignOf<long>(), alignOf<long long>()); + EXPECT_LE(alignOf<char>(), alignOf<float>()); + EXPECT_LE(alignOf<float>(), alignOf<double>()); + EXPECT_LE(alignOf<double>(), alignOf<long double>()); + EXPECT_LE(alignOf<char>(), alignOf<void *>()); + EXPECT_EQ(alignOf<void *>(), alignOf<int *>()); + EXPECT_LE(alignOf<char>(), alignOf<S1>()); + EXPECT_LE(alignOf<S1>(), alignOf<S2>()); + EXPECT_LE(alignOf<S1>(), alignOf<S3>()); + EXPECT_LE(alignOf<S1>(), alignOf<S4>()); + EXPECT_LE(alignOf<S1>(), alignOf<S5>()); + EXPECT_LE(alignOf<S1>(), alignOf<S6>()); + EXPECT_LE(alignOf<S1>(), alignOf<D1>()); + EXPECT_LE(alignOf<S1>(), alignOf<D2>()); + EXPECT_LE(alignOf<S1>(), alignOf<D3>()); + EXPECT_LE(alignOf<S1>(), alignOf<D4>()); + EXPECT_LE(alignOf<S1>(), alignOf<D5>()); + EXPECT_LE(alignOf<S1>(), alignOf<D6>()); + EXPECT_LE(alignOf<S1>(), alignOf<D7>()); + EXPECT_LE(alignOf<S1>(), alignOf<D8>()); + EXPECT_LE(alignOf<S1>(), alignOf<D9>()); + EXPECT_LE(alignOf<S1>(), alignOf<V1>()); + EXPECT_LE(alignOf<V1>(), alignOf<V2>()); + EXPECT_LE(alignOf<V1>(), alignOf<V3>()); + EXPECT_LE(alignOf<V1>(), alignOf<V4>()); + EXPECT_LE(alignOf<V1>(), alignOf<V5>()); + EXPECT_LE(alignOf<V1>(), alignOf<V6>()); + EXPECT_LE(alignOf<V1>(), alignOf<V7>()); + EXPECT_LE(alignOf<V1>(), alignOf<V8>()); +} + +TEST(AlignOfTest, BasicAlignedArray) { + // Note: this code exclusively uses the struct-wrapped arbitrarily aligned + // types because of the bugs mentioned above where GCC and Clang both + // disregard the arbitrary alignment specifier until the type is used to + // declare a member of a struct. + EXPECT_LE(1u, alignOf<AlignedCharArray<SA1>::union_type>()); + EXPECT_LE(2u, alignOf<AlignedCharArray<SA2>::union_type>()); + EXPECT_LE(4u, alignOf<AlignedCharArray<SA4>::union_type>()); + EXPECT_LE(8u, alignOf<AlignedCharArray<SA8>::union_type>()); + + EXPECT_LE(1u, sizeof(AlignedCharArray<SA1>::union_type)); + EXPECT_LE(2u, sizeof(AlignedCharArray<SA2>::union_type)); + EXPECT_LE(4u, sizeof(AlignedCharArray<SA4>::union_type)); + EXPECT_LE(8u, sizeof(AlignedCharArray<SA8>::union_type)); + + EXPECT_EQ(1u, (alignOf<AlignedCharArray<SA1>::union_type>())); + EXPECT_EQ(2u, (alignOf<AlignedCharArray<SA1, SA2>::union_type>())); + EXPECT_EQ(4u, (alignOf<AlignedCharArray<SA1, SA2, SA4>::union_type>())); + EXPECT_EQ(8u, (alignOf<AlignedCharArray<SA1, SA2, SA4, SA8>::union_type>())); + + EXPECT_EQ(1u, sizeof(AlignedCharArray<SA1>::union_type)); + EXPECT_EQ(2u, sizeof(AlignedCharArray<SA1, SA2>::union_type)); + EXPECT_EQ(4u, sizeof(AlignedCharArray<SA1, SA2, SA4>::union_type)); + EXPECT_EQ(8u, sizeof(AlignedCharArray<SA1, SA2, SA4, SA8>::union_type)); + + EXPECT_EQ(1u, (alignOf<AlignedCharArray<SA1[1]>::union_type>())); + EXPECT_EQ(2u, (alignOf<AlignedCharArray<SA1[2], SA2[1]>::union_type>())); + EXPECT_EQ(4u, (alignOf<AlignedCharArray<SA1[42], SA2[55], + SA4[13]>::union_type>())); + EXPECT_EQ(8u, (alignOf<AlignedCharArray<SA1[2], SA2[1], + SA4, SA8>::union_type>())); + + EXPECT_EQ(1u, sizeof(AlignedCharArray<SA1[1]>::union_type)); + EXPECT_EQ(2u, sizeof(AlignedCharArray<SA1[2], SA2[1]>::union_type)); + EXPECT_EQ(4u, sizeof(AlignedCharArray<SA1[3], SA2[2], SA4>::union_type)); + EXPECT_EQ(16u, sizeof(AlignedCharArray<SA1, SA2[3], + SA4[3], SA8>::union_type)); + + // For other tests we simply assert that the alignment of the union mathes + // that of the fundamental type and hope that we have any weird type + // productions that would trigger bugs. + EXPECT_EQ(alignOf<char>(), alignOf<AlignedCharArray<char>::union_type>()); + EXPECT_EQ(alignOf<short>(), alignOf<AlignedCharArray<short>::union_type>()); + EXPECT_EQ(alignOf<int>(), alignOf<AlignedCharArray<int>::union_type>()); + EXPECT_EQ(alignOf<long>(), alignOf<AlignedCharArray<long>::union_type>()); + EXPECT_EQ(alignOf<long long>(), + alignOf<AlignedCharArray<long long>::union_type>()); + EXPECT_EQ(alignOf<float>(), alignOf<AlignedCharArray<float>::union_type>()); + EXPECT_EQ(alignOf<double>(), alignOf<AlignedCharArray<double>::union_type>()); + EXPECT_EQ(alignOf<long double>(), + alignOf<AlignedCharArray<long double>::union_type>()); + EXPECT_EQ(alignOf<void *>(), alignOf<AlignedCharArray<void *>::union_type>()); + EXPECT_EQ(alignOf<int *>(), alignOf<AlignedCharArray<int *>::union_type>()); + EXPECT_EQ(alignOf<double (*)(double)>(), + alignOf<AlignedCharArray<double (*)(double)>::union_type>()); + EXPECT_EQ(alignOf<double (S6::*)()>(), + alignOf<AlignedCharArray<double (S6::*)()>::union_type>()); + EXPECT_EQ(alignOf<S1>(), alignOf<AlignedCharArray<S1>::union_type>()); + EXPECT_EQ(alignOf<S2>(), alignOf<AlignedCharArray<S2>::union_type>()); + EXPECT_EQ(alignOf<S3>(), alignOf<AlignedCharArray<S3>::union_type>()); + EXPECT_EQ(alignOf<S4>(), alignOf<AlignedCharArray<S4>::union_type>()); + EXPECT_EQ(alignOf<S5>(), alignOf<AlignedCharArray<S5>::union_type>()); + EXPECT_EQ(alignOf<S6>(), alignOf<AlignedCharArray<S6>::union_type>()); + EXPECT_EQ(alignOf<D1>(), alignOf<AlignedCharArray<D1>::union_type>()); + EXPECT_EQ(alignOf<D2>(), alignOf<AlignedCharArray<D2>::union_type>()); + EXPECT_EQ(alignOf<D3>(), alignOf<AlignedCharArray<D3>::union_type>()); + EXPECT_EQ(alignOf<D4>(), alignOf<AlignedCharArray<D4>::union_type>()); + EXPECT_EQ(alignOf<D5>(), alignOf<AlignedCharArray<D5>::union_type>()); + EXPECT_EQ(alignOf<D6>(), alignOf<AlignedCharArray<D6>::union_type>()); + EXPECT_EQ(alignOf<D7>(), alignOf<AlignedCharArray<D7>::union_type>()); + EXPECT_EQ(alignOf<D8>(), alignOf<AlignedCharArray<D8>::union_type>()); + EXPECT_EQ(alignOf<D9>(), alignOf<AlignedCharArray<D9>::union_type>()); + EXPECT_EQ(alignOf<V1>(), alignOf<AlignedCharArray<V1>::union_type>()); + EXPECT_EQ(alignOf<V2>(), alignOf<AlignedCharArray<V2>::union_type>()); + EXPECT_EQ(alignOf<V3>(), alignOf<AlignedCharArray<V3>::union_type>()); + EXPECT_EQ(alignOf<V4>(), alignOf<AlignedCharArray<V4>::union_type>()); + EXPECT_EQ(alignOf<V5>(), alignOf<AlignedCharArray<V5>::union_type>()); + EXPECT_EQ(alignOf<V6>(), alignOf<AlignedCharArray<V6>::union_type>()); + EXPECT_EQ(alignOf<V7>(), alignOf<AlignedCharArray<V7>::union_type>()); + EXPECT_EQ(alignOf<V8>(), alignOf<AlignedCharArray<V8>::union_type>()); +} + +} |