[llvm] r291503 - Lift the 10-type limit for AlignedCharArrayUnion
Reid Kleckner via llvm-commits
llvm-commits at lists.llvm.org
Fri Jan 13 08:45:18 PST 2017
Yeah, sorry, Takumi's email about the linux failure fell out of my inbox
somehow and I didn't take action on it.
i686-linux seems to have this problem:
struct Double { double d; };
static_assert(alignof(double) == 8, "");
static_assert(alignof(Double) == 4, "");
Both asserts pass and that is... a little insane. Both should report 4,
unless -malign-double is enabled. I recall this was something we had to do
for GCC compatibility, which reports the preferred alignment for
alignof(double) instead of the required alignment.
On Thu, Jan 12, 2017 at 5:24 PM, NAKAMURA Takumi <geek4civic at gmail.com>
wrote:
> Reverted in r291875.
>
> Hans, I supposed you would make the branch later. Would it be too late?
>
> On Fri, Jan 13, 2017 at 3:53 AM Hans Wennborg <hans at chromium.org> wrote:
>
>> 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>));
>> >
>> >
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>>
>
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