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new_delete_resource (#33)
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@kelbon
kelbon authored Oct 13, 2024
1 parent d38bccb commit afcffb0
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Showing 3 changed files with 105 additions and 89 deletions.
172 changes: 99 additions & 73 deletions include/kelcoro/memory_support.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,15 +8,88 @@

namespace dd {

consteval size_t coroframe_align() {
// Question: what will be if coroutine local contains alignas(64) int i; ?
// Answer: (quote from std::generator paper)
// "Let BAlloc be allocator_traits<A>::template rebind_alloc<U> where U denotes an unspecified type
// whose size and alignment are both _STDCPP_DEFAULT_NEW_ALIGNMENT__"
return __STDCPP_DEFAULT_NEW_ALIGNMENT__;
}

template <typename T>
concept memory_resource = (!std::is_reference_v<T>)&&requires(T value, size_t sz, size_t align, void* ptr) {
{ value.allocate(sz, align) } -> std::convertible_to<void*>;
{ value.deallocate(ptr, sz, align) } noexcept -> std::same_as<void>;
concept memory_resource = !std::is_reference_v<T> && requires(T value, size_t sz, void* ptr) {
// align of result must be atleast aligned as dd::coroframe_align()
// align arg do not required, because standard do not provide interface
// for passing alignment to promise_type::new
{ value.allocate(sz) } -> std::convertible_to<void*>;
{ value.deallocate(ptr, sz) } noexcept -> std::same_as<void>;
requires std::is_nothrow_move_constructible_v<T>;
requires alignof(T) <= alignof(std::max_align_t);
requires !(std::is_empty_v<T> && !std::default_initializable<T>);
};

// typical usage:
// using with_my_resource = dd::with_resource<chunk_from<MyResource>>;
// coro foo(int, double, with_my_resource);
// ...
// foo(5, 3.14, my_resource);
template <typename R>
struct chunk_from {
private:
KELCORO_NO_UNIQUE_ADDRESS std::conditional_t<std::is_empty_v<R>, R, R*> _resource;

public:
R& resource() noexcept {
if constexpr (std::is_empty_v<R>)
return _resource;
else
return *_resource;
}

// implicit
chunk_from(R& r) noexcept {
if constexpr (!std::is_empty_v<R>)
_resource = std::addressof(r);
}

void* allocate(size_t sz) {
return std::assume_aligned<dd::coroframe_align()>(resource().allocate(sz));
}

void deallocate(void* p, std::size_t sz) noexcept {
resource().deallocate(p, sz);
}
};

// default resource for with_memory_resource
struct new_delete_resource {
static void* allocate(size_t sz) {
// not malloc because of memory alignment requirement
return new char[sz];
}
static void deallocate(void* p, std::size_t) noexcept {
delete[] static_cast<char*>(p);
}
};

// when passed into coroutine as last argument coro will allocate/deallocate memory using this resource
// example:
// generator<int> gen(int, float, with_resource<MyResource>);
template <memory_resource R>
struct with_resource {
KELCORO_NO_UNIQUE_ADDRESS R resource;

// implicit
template <typename... Args>
with_resource(Args&&... args) noexcept(std::is_nothrow_constructible_v<R, Args&&...>)
: resource(std::forward<Args>(args)...) {
}
};

template <typename X>
with_resource(X&&) -> with_resource<std::remove_cvref_t<X>>;
with_resource(std::pmr::memory_resource&) -> with_resource<chunk_from<std::pmr::memory_resource>>;

namespace pmr {

struct polymorphic_resource {
Expand Down Expand Up @@ -44,11 +117,11 @@ struct polymorphic_resource {
}
polymorphic_resource(std::pmr::memory_resource& m) noexcept : passed(&m) {
}
void* allocate(size_t sz, size_t align) {
return passed->allocate(sz, align);
void* allocate(size_t sz) {
return passed->allocate(sz, coroframe_align());
}
void deallocate(void* p, std::size_t sz, std::size_t align) noexcept {
passed->deallocate(p, sz, align);
void deallocate(void* p, std::size_t sz) noexcept {
passed->deallocate(p, sz, coroframe_align());
}
};

Expand All @@ -63,59 +136,10 @@ inline void pass_resource(std::pmr::memory_resource& m) noexcept {
polymorphic_resource::passed_resource() = &m;
}

struct std_pmr_resource {
private:
std::pmr::memory_resource* mr;

public:
std_pmr_resource(std::pmr::memory_resource& r) noexcept : mr(&r) {
}
void* allocate(size_t sz, size_t align) {
return mr->allocate(sz, align);
}
void deallocate(void* p, std::size_t sz, std::size_t align) noexcept {
mr->deallocate(p, sz, align);
}
};

} // namespace pmr

consteval size_t coroframe_align() {
// Question: what will be if coroutine local contains alignas(64) int i; ?
// Answer: (quote from std::generator paper)
// "Let BAlloc be allocator_traits<A>::template rebind_alloc<U> where U denotes an unspecified type
// whose size and alignment are both _STDCPP_DEFAULT_NEW_ALIGNMENT__"
return __STDCPP_DEFAULT_NEW_ALIGNMENT__;
}

// TODO free list with customizable max blocks
// must be good because coroutines have same sizes,
// its easy to reuse memory for them
// TODO info about current channel/generator call, is_top, handle, iteration from top to bot/reverse, swap two
// generators in chain
// struct co_memory_resource { ... };

// when passed into coroutine coro will allocate/deallocate memory using this resource
template <memory_resource R>
struct with_resource {
KELCORO_NO_UNIQUE_ADDRESS R resource;
};
template <typename X>
with_resource(X&&) -> with_resource<std::remove_cvref_t<X>>;
with_resource(std::pmr::memory_resource&) -> with_resource<pmr::polymorphic_resource>;

// specialization for implicit ctor
template <>
struct with_resource<pmr::std_pmr_resource> {
pmr::std_pmr_resource resource;

with_resource(std::pmr::memory_resource& mr) noexcept : resource(mr) {
}
with_resource(pmr::std_pmr_resource mr) noexcept : resource(std::move(mr)) {
}
};

using with_pmr_resource = with_resource<pmr::std_pmr_resource>;
using with_default_resource = with_resource<new_delete_resource>;
using with_pmr_resource = with_resource<chunk_from<std::pmr::memory_resource>>;

namespace noexport {

Expand Down Expand Up @@ -170,16 +194,13 @@ constexpr size_t padding_len(size_t sz) noexcept {
template <memory_resource R>
struct overload_new_delete {
private:
enum { frame_align = std::max(coroframe_align(), alignof(R)) };
static void* do_allocate(size_t frame_sz, R& r) {
if constexpr (std::is_empty_v<R>)
return (void*)r.allocate(frame_sz, coroframe_align());
return (void*)r.allocate(frame_sz);
else {
const size_t padding = noexport::padding_len<frame_align>(frame_sz);
const size_t bytes_count = frame_sz + padding + sizeof(R);
std::byte* p = (std::byte*)r.allocate(bytes_count, frame_align);
std::byte* resource_place = p + frame_sz + padding;
std::construct_at((R*)resource_place, std::move(r));
frame_sz += noexport::padding_len<alignof(R)>(frame_sz);
std::byte* p = (std::byte*)r.allocate(frame_sz + sizeof(R));
new (p + frame_sz) R(std::move(r));
return p;
}
}
Expand All @@ -205,15 +226,19 @@ struct overload_new_delete {
static void operator delete(void* ptr, std::size_t frame_sz) noexcept {
if constexpr (std::is_empty_v<R>) {
R r{};
r.deallocate(ptr, frame_sz, coroframe_align());
r.deallocate(ptr, frame_sz);
} else {
const size_t padding = noexport::padding_len<frame_align>(frame_sz);
const size_t bytes_count = frame_sz + padding + sizeof(R);
R* onframe_resource = (R*)((std::byte*)ptr + frame_sz + padding);
frame_sz += noexport::padding_len<alignof(R)>(frame_sz);
R* onframe_resource = (R*)((std::byte*)ptr + frame_sz);
assert((((uintptr_t)onframe_resource % alignof(R)) == 0));
R r = std::move(*onframe_resource);
std::destroy_at(onframe_resource);
r.deallocate(ptr, bytes_count, frame_align);
if constexpr (std::is_trivially_destructible_v<R>) {
onframe_resource->deallocate(ptr, frame_sz + sizeof(R));
} else {
// save to stack from deallocated memory
R r = std::move(*onframe_resource);
std::destroy_at(onframe_resource);
r.deallocate(ptr, frame_sz + sizeof(R));
}
}
}
};
Expand Down Expand Up @@ -289,7 +314,8 @@ struct coroutine_traits<::dd::resourced<Coro, R>, Args...> {

// enable_resource_deduction always uses last argument if present (memory_resource<R>)
template <typename Coro, typename... Args>
requires(derived_from<Coro, ::dd::enable_resource_deduction> && dd::last_is_memory_resource_tag<Args...>)
requires(derived_from<Coro, ::dd::enable_resource_deduction> && dd::last_is_memory_resource_tag<Args...> &&
!std::is_same_v<dd::noexport::last_type_t<Args...>, dd::with_default_resource>)
struct coroutine_traits<Coro, Args...> {
using promise_type = ::dd::resourced_promise<typename Coro::promise_type, ::dd::resource_type_t<Args...>>;
};
Expand Down
9 changes: 5 additions & 4 deletions tests/test_coroutines.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -93,8 +93,8 @@ TEST(allocations) {
static_assert(std::is_same_v<decltype(x0), with_resource<r>>);
}
struct some_resource {
void* allocate(size_t, size_t);
void deallocate(void*, size_t, size_t) noexcept;
void* allocate(size_t);
void deallocate(void*, size_t) noexcept;
};
// resource deduction
{
Expand All @@ -110,7 +110,8 @@ TEST(allocations) {
EXPECT_PROMISE(expected, test_t, float, float, double, int, with_resource<r>); \
EXPECT_PROMISE(default_promise, test_t, float, float, double, int, with_resource<r>, int); \
EXPECT_PROMISE(some_resource_promise, test_t, float, float, double, int, with_resource<r>&, \
with_resource<some_resource>)
with_resource<some_resource>); \
EXPECT_PROMISE(default_promise, test_t, float, dd::with_default_resource)
TEST_DEDUCTED;
}
{
Expand Down Expand Up @@ -827,7 +828,7 @@ struct test_mem_resource : std::pmr::memory_resource {
};

dd::generator<int> gen_with_alloc(std::string val, dd::with_pmr_resource = *std::pmr::new_delete_resource()) {
for (int i = 0; i < 100; ++i)
for (alignas(64) int i = 0; i < 100; ++i)
co_yield i;
}

Expand Down
13 changes: 1 addition & 12 deletions tests/test_generator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -659,18 +659,7 @@ struct log_resource : std::pmr::memory_resource {
}

inline auto sz = size_t(-1);
struct new_delete_resource {
void* allocate(size_t s, size_t a) {
sz = s;
(void)a; // cannot use new with 'align_val_t' on msvc... Its broken
return malloc(s);
}
void deallocate(void* p, size_t s, size_t a) noexcept {
sz -= s;
(void)a;
free(p);
}
};
using new_delete_resource = dd::new_delete_resource;
dd::generator_r<int, new_delete_resource> new_ints() {
co_yield 1;
}
Expand Down

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