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enable algiment of control structures on stack

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Oliver Kowalke
2015-06-10 20:52:14 +02:00
parent 5f2c8e47d4
commit baf9a55868
1 changed files with 13 additions and 0 deletions
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13
include/boost/fiber/fiber.hpp
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@@ -44,9 +44,22 @@ private:
template< typename StackAlloc, typename Fn, typename ... Args >
static ptr_t create( StackAlloc salloc, Fn && fn, Args && ... args) {
context::stack_context sctx( salloc.allocate() );
#if defined(BOOST_NO_CXX14_CONSTEXPR) || defined(BOOST_NO_CXX11_STD_ALIGN)
// reserve space for control structure
std::size_t size = sctx.size - sizeof( fiber_context);
void * sp = static_cast< char * >( sctx.sp) - sizeof( fiber_context);
#else
constexpr std::size_t func_alignment = 64; // alignof( fiber_context);
constexpr std::size_t func_size = sizeof( fiber_context);
// reserve space on stack
void * sp = static_cast< char * >( sctx.sp) - func_size - func_alignment;
// align sp pointer
std::size_t space = func_size + func_alignment;
sp = std::align( func_alignment, func_size, sp, space);
BOOST_ASSERT( nullptr != sp);
// calculate remaining size
std::size_t size = sctx.size - ( static_cast< char * >( sctx.sp) - static_cast< char * >( sp) );
#endif
// placement new of fiber_context on top of fiber's stack
return ptr_t(
new ( sp) fiber_context( context::preallocated( sp, size, sctx), salloc,