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do not store the allocator/stack pointer directly, also call stack allocator dtor

master
Daniel Kolesa 2017-03-15 01:19:01 +01:00
parent 78d6a23ad3
commit ce155190e0
1 changed files with 22 additions and 12 deletions
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34
ostd/internal/context.hh
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@ -49,12 +49,10 @@ protected:
coroutine_context(coroutine_context const &) = delete;
coroutine_context(coroutine_context &&c):
p_stack(std::move(c.p_stack)), p_coro(c.p_coro), p_orig(c.p_orig),
p_except(std::move(c.p_except)), p_state(std::move(c.p_state)),
p_sa(c.p_sa)
p_except(std::move(c.p_except)), p_state(std::move(c.p_state))
{
c.p_coro = c.p_orig = nullptr;
c.p_stack = { nullptr, 0 };
c.p_sa = nullptr;
c.set_dead();
}
@ -100,28 +98,38 @@ protected:
swap(p_orig, other.p_orig);
swap(p_except, other.p_except);
swap(p_state, other.p_state);
swap(p_sa, other.p_sa);
}
template<typename C, typename SA>
void make_context(SA &sa) {
p_stack = sa.allocate();
void *sp = get_stack_ptr<SA>();
size_t asize = p_stack.size -
(static_cast<byte *>(p_stack.ptr) - static_cast<byte *>(sp));
p_coro = ostd_make_fcontext(sp, asize, &context_call<C, SA>);
new (sp) SA(std::move(sa));
}
private:
/* we also store the stack allocator at the end of the stack */
template<typename SA>
void *get_stack_ptr() {
/* 16 byte stack pointer alignment */
constexpr size_t salign = 16;
/* makes enough space so that we can store the allocator at
* stack pointer location (we'll need it for dealloc later)
*/
constexpr size_t sasize = sizeof(SA);
void *sp = static_cast<byte *>(p_stack.ptr) - sasize - salign;
size_t space = sasize + salign;
sp = std::align(salign, sasize, sp, space);
size_t asize = p_stack.size -
(static_cast<byte *>(p_stack.ptr) - static_cast<byte *>(sp));
p_coro = ostd_make_fcontext(sp, asize, &context_call<C, SA>);
p_sa = new (sp) SA(std::move(sa));
return sp;
}
private:
struct forced_unwind {
fcontext_t ctx;
forced_unwind(fcontext_t c): ctx(c) {}
@ -159,8 +167,11 @@ private:
set_dead();
ostd_ontop_fcontext(p_orig, this, [](transfer_t t) -> transfer_t {
auto &self = *(static_cast<coroutine_context *>(t.data));
auto &sa = *(static_cast<SA *>(self.p_sa));
sa.deallocate(self.p_stack);
auto &sa = *(static_cast<SA *>(self.get_stack_ptr<SA>()));
SA dsa{std::move(sa)};
/* in case it holds any state that needs destroying */
sa.~SA();
dsa.deallocate(self.p_stack);
return { nullptr, nullptr };
});
}
@ -194,7 +205,6 @@ release:
fcontext_t p_orig;
std::exception_ptr p_except;
state p_state = state::HOLD;
void *p_sa = nullptr;
};
} /* namespace detail */