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-rw-r--r--boost/context/execution_context_winfib.ipp407
1 files changed, 230 insertions, 177 deletions
diff --git a/boost/context/execution_context_winfib.ipp b/boost/context/execution_context_winfib.ipp
index 7b0a92b550..1b106fa245 100644
--- a/boost/context/execution_context_winfib.ipp
+++ b/boost/context/execution_context_winfib.ipp
@@ -13,6 +13,8 @@
#include <windows.h>
+#include <algorithm>
+#include <atomic>
#include <cstddef>
#include <cstdint>
#include <cstdlib>
@@ -25,6 +27,7 @@
#include <boost/intrusive_ptr.hpp>
#include <boost/context/detail/invoke.hpp>
+#include <boost/context/fixedsize_stack.hpp>
#include <boost/context/stack_context.hpp>
#ifdef BOOST_HAS_ABI_HEADERS
@@ -33,132 +36,162 @@
namespace boost {
namespace context {
+namespace detail {
-struct preallocated {
- void * sp;
- std::size_t size;
- stack_context sctx;
+struct activation_record {
+ typedef boost::intrusive_ptr< activation_record > ptr_t;
- preallocated( void * sp_, std::size_t size_, stack_context sctx_) noexcept :
- sp( sp_), size( size_), sctx( sctx_) {
- }
-};
+ enum flag_t {
+ flag_main_ctx = 1 << 1,
+ flag_preserve_fpu = 1 << 2,
+ flag_segmented_stack = 1 << 3
+ };
-class BOOST_CONTEXT_DECL execution_context {
-private:
- struct activation_record {
- typedef boost::intrusive_ptr< activation_record > ptr_t;
-
- enum flag_t {
- flag_main_ctx = 1 << 1,
- flag_preserve_fpu = 1 << 2,
- flag_segmented_stack = 1 << 3
- };
-
- thread_local static activation_record toplevel_rec;
- thread_local static ptr_t current_rec;
-
- std::size_t use_count;
- LPVOID fiber;
- stack_context sctx;
- int flags;
-
- // used for toplevel-context
- // (e.g. main context, thread-entry context)
- activation_record() noexcept :
- use_count( 1),
- fiber( nullptr),
- sctx(),
- flags( flag_main_ctx) {
- }
-
- activation_record( stack_context sctx_, bool use_segmented_stack) noexcept :
- use_count( 0),
- fiber( nullptr),
- sctx( sctx_),
- flags( use_segmented_stack ? flag_segmented_stack : 0) {
- }
-
- virtual ~activation_record() noexcept = default;
-
- void resume() noexcept {
- // store current activation record in local variable
- activation_record * from = current_rec.get();
- // store `this` in static, thread local pointer
- // `this` will become the active (running) context
- // returned by execution_context::current()
- current_rec = this;
- // context switch from parent context to `this`-context
+ thread_local static ptr_t current_rec;
+
+ std::atomic< std::size_t > use_count;
+ LPVOID fiber;
+ stack_context sctx;
+ void * data;
+ int flags;
+
+ // used for toplevel-context
+ // (e.g. main context, thread-entry context)
+ activation_record() noexcept :
+ use_count( 0),
+ fiber( nullptr),
+ sctx(),
+ flags( flag_main_ctx
+# if defined(BOOST_USE_SEGMENTED_STACKS)
+ | flag_segmented_stack
+# endif
+ ) {
+ }
+
+ activation_record( stack_context sctx_, bool use_segmented_stack) noexcept :
+ use_count( 0),
+ fiber( nullptr),
+ sctx( sctx_),
+ data( nullptr),
+ flags( use_segmented_stack ? flag_segmented_stack : 0) {
+ }
+
+ virtual ~activation_record() noexcept = default;
+
+ void * resume( void * vp, bool fpu) noexcept {
+ // store current activation record in local variable
+ activation_record * from = current_rec.get();
+ // store `this` in static, thread local pointer
+ // `this` will become the active (running) context
+ // returned by execution_context::current()
+ current_rec = this;
+ // context switch from parent context to `this`-context
#if ( _WIN32_WINNT > 0x0600)
- if ( ::IsThreadAFiber() ) {
- from->fiber = ::GetCurrentFiber();
- } else {
- from->fiber = ::ConvertThreadToFiber( nullptr);
- }
-#else
+ if ( ::IsThreadAFiber() ) {
+ from->fiber = ::GetCurrentFiber();
+ } else {
from->fiber = ::ConvertThreadToFiber( nullptr);
- if ( nullptr == from->fiber) {
- DWORD err = ::GetLastError();
- BOOST_ASSERT( ERROR_ALREADY_FIBER == err);
- from->fiber = ::GetCurrentFiber();
- BOOST_ASSERT( nullptr != from->fiber);
- BOOST_ASSERT( reinterpret_cast< LPVOID >( 0x1E00) != from->fiber);
- }
-#endif
- ::SwitchToFiber( fiber);
}
+#else
+ from->fiber = ::ConvertThreadToFiber( nullptr);
+ if ( nullptr == from->fiber) {
+ DWORD err = ::GetLastError();
+ BOOST_ASSERT( ERROR_ALREADY_FIBER == err);
+ from->fiber = ::GetCurrentFiber();
+ BOOST_ASSERT( nullptr != from->fiber);
+ BOOST_ASSERT( reinterpret_cast< LPVOID >( 0x1E00) != from->fiber);
+ }
+#endif
+ // store passed argument (void pointer)
+ data = vp;
+ // context switch
+ ::SwitchToFiber( fiber);
+ // access the activation-record of the current fiber
+ activation_record * ar = static_cast< activation_record * >( GetFiberData() );
+ return nullptr != ar ? ar->data : nullptr;
+ }
- virtual void deallocate() {}
+ virtual void deallocate() {
+ delete this;
+ }
- friend void intrusive_ptr_add_ref( activation_record * ar) {
- ++ar->use_count;
- }
+ friend void intrusive_ptr_add_ref( activation_record * ar) {
+ ++ar->use_count;
+ }
- friend void intrusive_ptr_release( activation_record * ar) {
- BOOST_ASSERT( nullptr != ar);
+ friend void intrusive_ptr_release( activation_record * ar) {
+ BOOST_ASSERT( nullptr != ar);
- if ( 0 == --ar->use_count) {
- ar->deallocate();
- }
+ if ( 0 == --ar->use_count) {
+ ar->deallocate();
}
- };
+ }
+};
- template< typename Fn, typename StackAlloc >
- class capture_record : public activation_record {
- private:
- StackAlloc salloc_;
- Fn fn_;
-
- static void destroy( capture_record * p) {
- StackAlloc salloc( p->salloc_);
- stack_context sctx( p->sctx);
- // deallocate activation record
- p->~capture_record();
- // destroy stack with stack allocator
- salloc.deallocate( sctx);
- }
+struct activation_record_initializer {
+ activation_record_initializer();
+ ~activation_record_initializer();
+};
- public:
- explicit capture_record( stack_context sctx, StackAlloc const& salloc, Fn && fn, bool use_segmented_stack) noexcept :
- activation_record( sctx, use_segmented_stack),
- salloc_( salloc),
- fn_( std::forward< Fn >( fn) ) {
- }
+template< typename Fn, typename Tpl, typename StackAlloc >
+class capture_record : public activation_record {
+private:
+ StackAlloc salloc_;
+ Fn fn_;
+ Tpl tpl_;
+ activation_record * caller_;
+
+ static void destroy( capture_record * p) {
+ StackAlloc salloc( p->salloc_);
+ stack_context sctx( p->sctx);
+ // deallocate activation record
+ p->~capture_record();
+ // destroy stack with stack allocator
+ salloc.deallocate( sctx);
+ }
- void deallocate() override final {
- destroy( this);
- }
+public:
+ explicit capture_record(
+ stack_context sctx, StackAlloc const& salloc,
+ Fn && fn, Tpl && tpl,
+ activation_record * caller,
+ bool use_segmented_stack) noexcept :
+ activation_record( sctx, use_segmented_stack),
+ salloc_( salloc),
+ fn_( std::forward< Fn >( fn) ),
+ tpl_( std::forward< Tpl >( tpl) ),
+ caller_( caller) {
+ }
- void run() noexcept {
- try {
- fn_();
- } catch (...) {
- std::terminate();
- }
- BOOST_ASSERT( 0 == (flags & flag_main_ctx) );
+ void deallocate() override final {
+ destroy( this);
+ }
+
+ void run() noexcept {
+ try {
+ void * vp = caller_->resume( caller_, true);
+ do_invoke( fn_, std::tuple_cat( tpl_, std::tie( vp) ) );
+ } catch (...) {
+ std::terminate();
}
- };
+ BOOST_ASSERT( 0 == (flags & flag_main_ctx) );
+ }
+};
+}
+
+struct preallocated {
+ void * sp;
+ std::size_t size;
+ stack_context sctx;
+
+ preallocated( void * sp_, std::size_t size_, stack_context sctx_) noexcept :
+ sp( sp_), size( size_), sctx( sctx_) {
+ }
+};
+
+class BOOST_CONTEXT_DECL execution_context {
+private:
// tampoline function
// entered if the execution context
// is resumed for the first time
@@ -173,23 +206,30 @@ private:
::DeleteFiber( ar->fiber);
}
- typedef boost::intrusive_ptr< activation_record > ptr_t;
+ typedef boost::intrusive_ptr< detail::activation_record > ptr_t;
ptr_t ptr_;
- template< typename StackAlloc, typename Fn >
- static activation_record * create_context( StackAlloc salloc, Fn && fn, bool use_segmented_stack) {
- typedef capture_record< Fn, StackAlloc > capture_t;
+ template< typename StackAlloc, typename Fn ,typename Tpl >
+ static detail::activation_record * create_context(
+ StackAlloc salloc,
+ Fn && fn, Tpl && tpl,
+ bool use_segmented_stack) {
+ typedef detail::capture_record< Fn, Tpl, StackAlloc > capture_t;
// hackish
std::size_t fsize = salloc.size_;
- salloc.size_ = sizeof( capture_t);
+ // protected_fixedsize_stack needs at least 2*page-size
+ salloc.size_ = ( std::max)( sizeof( capture_t), 2 * stack_traits::page_size() );
stack_context sctx( salloc.allocate() );
// reserve space for control structure
void * sp = static_cast< char * >( sctx.sp) - sizeof( capture_t);
- // placment new for control structure on fast-context stack
- capture_t * cr = new ( sp) capture_t( sctx, salloc, std::forward< Fn >( fn), use_segmented_stack);
+ // get current activation record
+ ptr_t curr = execution_context::current().ptr_;
+ // placement new for control structure on fast-context stack
+ capture_t * cr = new ( sp) capture_t(
+ sctx, salloc, std::forward< Fn >( fn), std::forward< Tpl >( tpl), curr.get(), use_segmented_stack);
// create fiber
// use default stacksize
cr->fiber = ::CreateFiber( fsize, execution_context::entry_func< capture_t >, cr);
@@ -197,18 +237,25 @@ private:
return cr;
}
- template< typename StackAlloc, typename Fn >
- static activation_record * create_context( preallocated palloc, StackAlloc salloc, Fn && fn, bool use_segmented_stack) {
- typedef capture_record< Fn, StackAlloc > capture_t;
+ template< typename StackAlloc, typename Fn , typename Tpl >
+ static detail::activation_record * create_context(
+ preallocated palloc, StackAlloc salloc,
+ Fn && fn, Tpl && tpl,
+ bool use_segmented_stack) {
+ typedef detail::capture_record< Fn, Tpl, StackAlloc > capture_t;
// hackish
std::size_t fsize = salloc.size_;
- salloc.size_ = sizeof( capture_t);
+ // protected_fixedsize_stack needs at least 2*page-size
+ salloc.size_ = ( std::max)( sizeof( capture_t), 2 * stack_traits::page_size() );
// reserve space for control structure
void * sp = static_cast< char * >( palloc.sp) - sizeof( capture_t);
- // placment new for control structure on fast-context stack
- capture_t * cr = new ( sp) capture_t( palloc.sctx, salloc, std::forward< Fn >( fn), use_segmented_stack);
+ // get current activation record
+ ptr_t curr = execution_context::current().ptr_;
+ // placement new for control structure on fast-context stack
+ capture_t * cr = new ( sp) capture_t(
+ palloc.sctx, salloc, std::forward< Fn >( fn), std::forward< Tpl >( tpl), curr.get(), use_segmented_stack);
// create fiber
// use default stacksize
cr->fiber = ::CreateFiber( fsize, execution_context::entry_func< capture_t >, cr);
@@ -216,84 +263,90 @@ private:
return cr;
}
- template< typename StackAlloc, typename Fn, typename Tpl, std::size_t ... I >
- static activation_record * create_capture_record( StackAlloc salloc,
- Fn && fn_, Tpl && tpl_,
- std::index_sequence< I ... >,
- bool use_segmented_stack) {
- return create_context(
- salloc,
- // lambda, executed in new execution context
- [fn=std::forward< Fn >( fn_),tpl=std::forward< Tpl >( tpl_)] () mutable -> decltype( auto) {
- detail::invoke( fn,
- // non-type template parameter pack used to extract the
- // parameters (arguments) from the tuple and pass them to fn
- // via parameter pack expansion
- // std::tuple_element<> does not perfect forwarding
- std::forward< decltype( std::get< I >( std::declval< Tpl >() ) ) >(
- std::get< I >( std::forward< Tpl >( tpl) ) ) ... );
- },
- use_segmented_stack);
- }
-
- template< typename StackAlloc, typename Fn, typename Tpl, std::size_t ... I >
- static activation_record * create_capture_record( preallocated palloc, StackAlloc salloc,
- Fn && fn_, Tpl && tpl_,
- std::index_sequence< I ... >,
- bool use_segmented_stack) {
- return create_context(
- palloc, salloc,
- // lambda, executed in new execution context
- [fn=std::forward< Fn >( fn_),tpl=std::forward< Tpl >( tpl_)] () mutable -> decltype( auto) {
- detail::invoke( fn,
- // non-type template parameter pack used to extract the
- // parameters (arguments) from the tuple and pass them to fn
- // via parameter pack expansion
- // std::tuple_element<> does not perfect forwarding
- std::forward< decltype( std::get< I >( std::declval< Tpl >() ) ) >(
- std::get< I >( std::forward< Tpl >( tpl) ) ) ... );
- },
- use_segmented_stack);
- }
-
execution_context() :
// default constructed with current activation_record
- ptr_( activation_record::current_rec) {
+ ptr_( detail::activation_record::current_rec) {
}
public:
- static execution_context current() noexcept {
- return execution_context();
+ static execution_context current() noexcept;
+
+ template< typename Fn, typename ... Args >
+ explicit execution_context( Fn && fn, Args && ... args) :
+ // deferred execution of fn and its arguments
+ // arguments are stored in std::tuple<>
+ // non-type template parameter pack via std::index_sequence_for<>
+ // preserves the number of arguments
+ // used to extract the function arguments from std::tuple<>
+ ptr_( create_context( fixedsize_stack(),
+ std::forward< Fn >( fn),
+ std::make_tuple( std::forward< Args >( args) ...),
+ false) ) {
+ ptr_->resume( ptr_.get(), true);
}
template< typename StackAlloc, typename Fn, typename ... Args >
- explicit execution_context( StackAlloc salloc, Fn && fn, Args && ... args) :
+ explicit execution_context( std::allocator_arg_t, StackAlloc salloc, Fn && fn, Args && ... args) :
// deferred execution of fn and its arguments
// arguments are stored in std::tuple<>
// non-type template parameter pack via std::index_sequence_for<>
// preserves the number of arguments
// used to extract the function arguments from std::tuple<>
- ptr_( create_capture_record( salloc,
- std::forward< Fn >( fn),
- std::make_tuple( std::forward< Args >( args) ... ),
- std::index_sequence_for< Args ... >(), false) ) {
+ ptr_( create_context( salloc,
+ std::forward< Fn >( fn),
+ std::make_tuple( std::forward< Args >( args) ...),
+ false) ) {
+ ptr_->resume( ptr_.get(), true);
}
template< typename StackAlloc, typename Fn, typename ... Args >
- explicit execution_context( preallocated palloc, StackAlloc salloc, Fn && fn, Args && ... args) :
+ explicit execution_context( std::allocator_arg_t, preallocated palloc, StackAlloc salloc, Fn && fn, Args && ... args) :
// deferred execution of fn and its arguments
// arguments are stored in std::tuple<>
// non-type template parameter pack via std::index_sequence_for<>
// preserves the number of arguments
// used to extract the function arguments from std::tuple<>
- ptr_( create_capture_record( palloc, salloc,
- std::forward< Fn >( fn),
- std::make_tuple( std::forward< Args >( args) ... ),
- std::index_sequence_for< Args ... >(), false) ) {
+ ptr_( create_context( palloc, salloc,
+ std::forward< Fn >( fn),
+ std::make_tuple( std::forward< Args >( args) ...),
+ false) ) {
+ ptr_->resume( ptr_.get(), true);
+ }
+
+ execution_context( execution_context const& other) noexcept :
+ ptr_( other.ptr_) {
+ }
+
+ execution_context( execution_context && other) noexcept :
+ ptr_( other.ptr_) {
+ other.ptr_.reset();
+ }
+
+ execution_context & operator=( execution_context const& other) noexcept {
+ if ( this != & other) {
+ ptr_ = other.ptr_;
+ }
+ return * this;
+ }
+
+ execution_context & operator=( execution_context && other) noexcept {
+ if ( this != & other) {
+ ptr_ = other.ptr_;
+ other.ptr_.reset();
+ }
+ return * this;
+ }
+
+ explicit operator bool() const noexcept {
+ return nullptr != ptr_.get();
+ }
+
+ bool operator!() const noexcept {
+ return nullptr == ptr_.get();
}
- void operator()( bool preserve_fpu = false) noexcept {
- ptr_->resume();
+ void * operator()( void * vp = nullptr, bool preserve_fpu = false) noexcept {
+ return ptr_->resume( vp, preserve_fpu);
}
};