[libcxx] Fix PR 22468 - std::function<void()> does not accept non-void-returning functions
Summary:
The bug can be found here: http://llvm.org/bugs/show_bug.cgi?id=22468
`__invoke_void_return_wrapper` is needed to properly handle calling a function that returns a value but where the std::function return type is void. Without this '-Wsystem-headers' will cause `function::operator()(...)` to not compile.
Reviewers: eugenis, K-ballo, mclow.lists
Reviewed By: mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D7444
llvm-svn: 228705
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 54519a6be9296fb115b949f1f0785d9cbfacc7c5
diff --git a/include/__functional_03 b/include/__functional_03
index d8a9f05..157d6bf 100644
--- a/include/__functional_03
+++ b/include/__functional_03
@@ -369,7 +369,8 @@
_Rp
__func<_Fp, _Alloc, _Rp()>::operator()()
{
- return __invoke(__f_.first());
+ typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+ return _Invoker::__call(__f_.first());
}
#ifndef _LIBCPP_NO_RTTI
@@ -452,7 +453,8 @@
_Rp
__func<_Fp, _Alloc, _Rp(_A0)>::operator()(_A0 __a0)
{
- return __invoke(__f_.first(), __a0);
+ typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+ return _Invoker::__call(__f_.first(), __a0);
}
#ifndef _LIBCPP_NO_RTTI
@@ -535,7 +537,8 @@
_Rp
__func<_Fp, _Alloc, _Rp(_A0, _A1)>::operator()(_A0 __a0, _A1 __a1)
{
- return __invoke(__f_.first(), __a0, __a1);
+ typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+ return _Invoker::__call(__f_.first(), __a0, __a1);
}
#ifndef _LIBCPP_NO_RTTI
@@ -618,7 +621,8 @@
_Rp
__func<_Fp, _Alloc, _Rp(_A0, _A1, _A2)>::operator()(_A0 __a0, _A1 __a1, _A2 __a2)
{
- return __invoke(__f_.first(), __a0, __a1, __a2);
+ typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+ return _Invoker::__call(__f_.first(), __a0, __a1, __a2);
}
#ifndef _LIBCPP_NO_RTTI
diff --git a/include/__functional_base b/include/__functional_base
index 6766793..e174e0c 100644
--- a/include/__functional_base
+++ b/include/__functional_base
@@ -419,6 +419,26 @@
typedef decltype(__invoke(_VSTD::declval<_Tp>(), _VSTD::declval<_Args>()...)) type;
};
+template <class _Ret>
+struct __invoke_void_return_wrapper
+{
+ template <class ..._Args>
+ static _Ret __call(_Args&&... __args)
+ {
+ return __invoke(_VSTD::forward<_Args>(__args)...);
+ }
+};
+
+template <>
+struct __invoke_void_return_wrapper<void>
+{
+ template <class ..._Args>
+ static void __call(_Args&&... __args)
+ {
+ __invoke(_VSTD::forward<_Args>(__args)...);
+ }
+};
+
template <class _Tp>
class _LIBCPP_TYPE_VIS_ONLY reference_wrapper
: public __weak_result_type<_Tp>
diff --git a/include/__functional_base_03 b/include/__functional_base_03
index 22c06ad..6550277 100644
--- a/include/__functional_base_03
+++ b/include/__functional_base_03
@@ -995,6 +995,63 @@
_VSTD::declval<_A2>())) type;
};
+template <class _Ret>
+struct __invoke_void_return_wrapper
+{
+ template <class _Fn>
+ static _Ret __call(_Fn __f)
+ {
+ return __invoke(__f);
+ }
+
+ template <class _Fn, class _A0>
+ static _Ret __call(_Fn __f, _A0& __a0)
+ {
+ return __invoke(__f, __a0);
+ }
+
+ template <class _Fn, class _A0, class _A1>
+ static _Ret __call(_Fn __f, _A0& __a0, _A1& __a1)
+ {
+ return __invoke(__f, __a0, __a1);
+ }
+
+ template <class _Fn, class _A0, class _A1, class _A2>
+ static _Ret __call(_Fn __f, _A0& __a0, _A1& __a1, _A2& __a2)
+ {
+ return __invoke(__f, __a0, __a1, __a2);
+ }
+};
+
+
+template <>
+struct __invoke_void_return_wrapper<void>
+{
+ template <class _Fn>
+ static void __call(_Fn __f)
+ {
+ __invoke(__f);
+ }
+
+ template <class _Fn, class _A0>
+ static void __call(_Fn __f, _A0& __a0)
+ {
+ __invoke(__f, __a0);
+ }
+
+ template <class _Fn, class _A0, class _A1>
+ static void __call(_Fn __f, _A0& __a0, _A1& __a1)
+ {
+ __invoke(__f, __a0, __a1);
+ }
+
+ template <class _Fn, class _A0, class _A1, class _A2>
+ static void __call(_Fn __f, _A0& __a0, _A1& __a1, _A2& __a2)
+ {
+ __invoke(__f, __a0, __a1, __a2);
+ }
+};
+
template <class _Tp>
class _LIBCPP_TYPE_VIS_ONLY reference_wrapper
: public __weak_result_type<_Tp>
diff --git a/include/functional b/include/functional
index d14b46b..36d422c 100644
--- a/include/functional
+++ b/include/functional
@@ -1367,7 +1367,8 @@
_Rp
__func<_Fp, _Alloc, _Rp(_ArgTypes...)>::operator()(_ArgTypes&& ... __arg)
{
- return __invoke(__f_.first(), _VSTD::forward<_ArgTypes>(__arg)...);
+ typedef __invoke_void_return_wrapper<_Rp> _Invoker;
+ return _Invoker::__call(__f_.first(), _VSTD::forward<_ArgTypes>(__arg)...);
}
#ifndef _LIBCPP_NO_RTTI
@@ -1429,7 +1430,7 @@
template <class _Fp>
struct __callable<_Fp, true>
{
- static const bool value =
+ static const bool value = is_same<void, _Rp>::value ||
is_convertible<typename __invoke_of<_Fp&, _ArgTypes...>::type,
_Rp>::value;
};