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poly: support for alignment requirements

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This commit is contained in:
Michele Caini
2021-03-22 12:00:21 +01:00
parent b05d84e8e3
commit 44fa466618
4 changed files with 66 additions and 12 deletions
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2
src/entt/poly/fwd.hpp
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@@ -5,7 +5,7 @@
namespace entt {
template<typename, std::size_t>
template<typename, std::size_t, std::size_t...>
class basic_poly;

24
src/entt/poly/poly.hpp
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@@ -46,25 +46,26 @@ struct poly_inspector {
* @brief Static virtual table factory.
* @tparam Concept Concept descriptor.
* @tparam Len Size of the storage reserved for the small buffer optimization.
* @tparam Align Optional alignment requirement.
*/
template<typename Concept, std::size_t Len>
template<typename Concept, std::size_t Len, std::size_t... Align>
class poly_vtable {
using inspector = typename Concept::template type<poly_inspector>;
template<typename Ret, typename... Args>
static auto vtable_entry(Ret(*)(inspector &, Args...)) -> Ret(*)(basic_any<Len> &, Args...);
static auto vtable_entry(Ret(*)(inspector &, Args...)) -> Ret(*)(basic_any<Len, Align...> &, Args...);
template<typename Ret, typename... Args>
static auto vtable_entry(Ret(*)(const inspector &, Args...)) -> Ret(*)(const basic_any<Len> &, Args...);
static auto vtable_entry(Ret(*)(const inspector &, Args...)) -> Ret(*)(const basic_any<Len, Align...> &, Args...);
template<typename Ret, typename... Args>
static auto vtable_entry(Ret(*)(Args...)) -> Ret(*)(const basic_any<Len> &, Args...);
static auto vtable_entry(Ret(*)(Args...)) -> Ret(*)(const basic_any<Len, Align...> &, Args...);
template<typename Ret, typename... Args>
static auto vtable_entry(Ret(inspector:: *)(Args...)) -> Ret(*)(basic_any<Len> &, Args...);
static auto vtable_entry(Ret(inspector:: *)(Args...)) -> Ret(*)(basic_any<Len, Align...> &, Args...);
template<typename Ret, typename... Args>
static auto vtable_entry(Ret(inspector:: *)(Args...) const) -> Ret(*)(const basic_any<Len> &, Args...);
static auto vtable_entry(Ret(inspector:: *)(Args...) const) -> Ret(*)(const basic_any<Len, Align...> &, Args...);
template<auto... Candidate>
static auto make_vtable(value_list<Candidate...>)
@@ -174,13 +175,14 @@ decltype(auto) poly_call(Poly &&self, Args &&... args) {
*
* @tparam Concept Concept descriptor.
* @tparam Len Size of the storage reserved for the small buffer optimization.
* @tparam Align Optional alignment requirement.
*/
template<typename Concept, std::size_t Len>
class basic_poly: private Concept::template type<poly_base<basic_poly<Concept, Len>>> {
template<typename Concept, std::size_t Len, std::size_t... Align>
class basic_poly: private Concept::template type<poly_base<basic_poly<Concept, Len, Align...>>> {
/*! @brief A poly base is allowed to snoop into a poly object. */
friend struct poly_base<basic_poly>;
using vtable_type = typename poly_vtable<Concept, Len>::type;
using vtable_type = typename poly_vtable<Concept, Len, Align...>::type;
public:
/*! @brief Concept type. */
@@ -201,7 +203,7 @@ public:
template<typename Type, typename... Args>
explicit basic_poly(std::in_place_type_t<Type>, Args &&... args)
: storage{std::in_place_type<Type>, std::forward<Args>(args)...},
vtable{poly_vtable<Concept, Len>::template instance<std::remove_const_t<std::remove_reference_t<Type>>>()}
vtable{poly_vtable<Concept, Len, Align...>::template instance<std::remove_const_t<std::remove_reference_t<Type>>>()}
{}
/**
@@ -338,7 +340,7 @@ public:
}
private:
basic_any<Len> storage;
basic_any<Len, Align...> storage;
const vtable_type *vtable;
};

26
test/entt/poly/poly_deduced.cpp
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@@ -41,6 +41,8 @@ struct impl {
int value{};
};
struct alignas(64u) over_aligned: impl {};
TEST(PolyDeduced, Functionalities) {
impl instance{};
@@ -227,3 +229,27 @@ TEST(PolyDeduced, SBOVsZeroedSBOSize) {
ASSERT_EQ(same->get(), 1);
}
TEST(PolyDeduced, Alignment) {
static constexpr auto alignment = alignof(over_aligned);
auto test = [](auto *target, auto cb) {
const auto *data = target[0].data();
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[0u].data()) % alignment) == 0u);
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[1u].data()) % alignment) == 0u);
std::swap(target[0], target[1]);
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[0u].data()) % alignment) == 0u);
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[1u].data()) % alignment) == 0u);
cb(data, target[1].data());
};
entt::basic_poly<Deduced, alignment> nosbo[2] = { over_aligned{}, over_aligned{} };
test(nosbo, [](auto *pre, auto *post) { ASSERT_EQ(pre, post); });
entt::basic_poly<Deduced, alignment, alignment> sbo[2] = { over_aligned{}, over_aligned{} };
test(sbo, [](auto *pre, auto *post) { ASSERT_NE(pre, post); });
}

26
test/entt/poly/poly_defined.cpp
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@@ -47,6 +47,8 @@ struct impl {
int value{};
};
struct alignas(64u) over_aligned: impl {};
TEST(PolyDefined, Functionalities) {
impl instance{};
@@ -233,3 +235,27 @@ TEST(PolyDefined, SBOVsZeroedSBOSize) {
ASSERT_EQ(same->get(), 1);
}
TEST(PolyDefined, Alignment) {
static constexpr auto alignment = alignof(over_aligned);
auto test = [](auto *target, auto cb) {
const auto *data = target[0].data();
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[0u].data()) % alignment) == 0u);
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[1u].data()) % alignment) == 0u);
std::swap(target[0], target[1]);
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[0u].data()) % alignment) == 0u);
ASSERT_TRUE((reinterpret_cast<std::uintptr_t>(target[1u].data()) % alignment) == 0u);
cb(data, target[1].data());
};
entt::basic_poly<Defined, alignment> nosbo[2] = { over_aligned{}, over_aligned{} };
test(nosbo, [](auto *pre, auto *post) { ASSERT_EQ(pre, post); });
entt::basic_poly<Defined, alignment, alignment> sbo[2] = { over_aligned{}, over_aligned{} };
test(sbo, [](auto *pre, auto *post) { ASSERT_NE(pre, post); });
}