[llvm] r291503 - Lift the 10-type limit for AlignedCharArrayUnion
Hans Wennborg via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 12 10:53:20 PST 2017
Takumi's buildbot started failing tests around this revision:
http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/33628/steps/test_all/logs/LLVM-Unit%20%3A%3A%20Support__SupportTests__AlignOfTest.BasicAlignedArray
Reid, I saw you landed some fixes after this as well.
I'm about create the branch for 4.0.0 later today. Please let me know
if something needs to be fixed here and merged to the branch.
Thanks,
Hans
On Mon, Jan 9, 2017 at 3:23 PM, Sean Callanan via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: spyffe
> Date: Mon Jan 9 17:23:25 2017
> New Revision: 291503
>
> URL: http://llvm.org/viewvc/llvm-project?rev=291503&view=rev
> Log:
> Lift the 10-type limit for AlignedCharArrayUnion
>
> This patch uses C++11 parameter packs and constexpr functions
> to allow AlignedCharArrayUnion to hold an arbitrary number of
> types.
>
> Differential Revision: https://reviews.llvm.org/D28429
>
> Modified:
> llvm/trunk/include/llvm/Support/AlignOf.h
> llvm/trunk/unittests/Support/AlignOfTest.cpp
>
> Modified: llvm/trunk/include/llvm/Support/AlignOf.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/AlignOf.h?rev=291503&r1=291502&r2=291503&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/Support/AlignOf.h (original)
> +++ llvm/trunk/include/llvm/Support/AlignOf.h Mon Jan 9 17:23:25 2017
> @@ -102,45 +102,38 @@ LLVM_ALIGNEDCHARARRAY_TEMPLATE_ALIGNMENT
>
> #endif // _MSC_VER
>
> +// This code implements the equivalent of std::aligned_union from C++11.
> +// That is supported by Visual Studio 2015 and GCC 5.1.
> +// Once these are the baselines for LLVM, we can use std::aligned_union instead.
> +
> namespace detail {
> -template <typename T1,
> - typename T2 = char, typename T3 = char, typename T4 = char,
> - typename T5 = char, typename T6 = char, typename T7 = char,
> - typename T8 = char, typename T9 = char, typename T10 = char>
> -class AlignerImpl {
> - T1 t1; T2 t2; T3 t3; T4 t4; T5 t5; T6 t6; T7 t7; T8 t8; T9 t9; T10 t10;
> +template <typename... Ts> class AlignerImpl;
>
> +template <typename T1, typename... Ts>
> +class AlignerImpl<T1, Ts...> : AlignerImpl<Ts...> {
> + T1 t;
> AlignerImpl() = delete;
> };
>
> -template <typename T1,
> - typename T2 = char, typename T3 = char, typename T4 = char,
> - typename T5 = char, typename T6 = char, typename T7 = char,
> - typename T8 = char, typename T9 = char, typename T10 = char>
> -union SizerImpl {
> - char arr1[sizeof(T1)], arr2[sizeof(T2)], arr3[sizeof(T3)], arr4[sizeof(T4)],
> - arr5[sizeof(T5)], arr6[sizeof(T6)], arr7[sizeof(T7)], arr8[sizeof(T8)],
> - arr9[sizeof(T9)], arr10[sizeof(T10)];
> -};
> +template <> class AlignerImpl<> { AlignerImpl() = delete; };
> +
> +template <typename T1> constexpr size_t sizer() { return sizeof(T1); }
> +
> +template <typename T1, typename T2, typename... Ts> constexpr size_t sizer() {
> + return (sizeof(T1) > sizer<T2, Ts...>()) ? sizeof(T1) : sizer<T2, Ts...>();
> +}
> } // end namespace detail
>
> /// \brief This union template exposes a suitably aligned and sized character
> -/// array member which can hold elements of any of up to ten types.
> +/// array member which can hold elements of any of a number of types.
> ///
> /// These types may be arrays, structs, or any other types. The goal is to
> /// expose a char array buffer member which can be used as suitable storage for
> -/// a placement new of any of these types. Support for more than ten types can
> -/// be added at the cost of more boilerplate.
> -template <typename T1,
> - typename T2 = char, typename T3 = char, typename T4 = char,
> - typename T5 = char, typename T6 = char, typename T7 = char,
> - typename T8 = char, typename T9 = char, typename T10 = char>
> -struct AlignedCharArrayUnion : llvm::AlignedCharArray<
> - alignof(llvm::detail::AlignerImpl<T1, T2, T3, T4, T5,
> - T6, T7, T8, T9, T10>),
> - sizeof(::llvm::detail::SizerImpl<T1, T2, T3, T4, T5,
> - T6, T7, T8, T9, T10>)> {
> -};
> +/// a placement new of any of these types.
> +template <typename... Ts>
> +struct AlignedCharArrayUnion
> + : llvm::AlignedCharArray<alignof(llvm::detail::AlignerImpl<Ts...>),
> + detail::sizer<Ts...>()> {};
> } // end namespace llvm
>
> #endif // LLVM_SUPPORT_ALIGNOF_H
>
> Modified: llvm/trunk/unittests/Support/AlignOfTest.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/AlignOfTest.cpp?rev=291503&r1=291502&r2=291503&view=diff
> ==============================================================================
> --- llvm/trunk/unittests/Support/AlignOfTest.cpp (original)
> +++ llvm/trunk/unittests/Support/AlignOfTest.cpp Mon Jan 9 17:23:25 2017
> @@ -91,6 +91,24 @@ V8::~V8() {}
>
> template <typename M> struct T { M m; };
>
> +typedef uint8_t t1;
> +typedef uint16_t t2;
> +typedef uint32_t t3;
> +typedef uint64_t t4;
> +typedef int8_t t5;
> +typedef int16_t t6;
> +typedef int32_t t7;
> +typedef int64_t t8;
> +typedef struct { uint8_t bytes[16]; } t9;
> +typedef struct { uint16_t words[16]; } t10;
> +typedef struct { uint32_t words[16]; } t11;
> +typedef struct { uint64_t words[16]; } t12;
> +
> +typedef AlignedCharArrayUnion<t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12> U;
> +
> +static_assert(sizeof(U) == sizeof(uint64_t[16]), "Statically-computed size must be right");
> +static_assert(alignof(U) == alignof(uint64_t), "Statically-computed alignment must be right");
> +
> TEST(AlignOfTest, BasicAlignedArray) {
> EXPECT_LE(1u, alignof(AlignedCharArrayUnion<A1>));
> EXPECT_LE(2u, alignof(AlignedCharArrayUnion<A2>));
>
>
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