To reduce instantiation count, function_ref(nontype<&S::x>, r) previously
reused the invoker from function_ref(nontype<&S::x>, &r). This assumed r was
always a reference to S or a derived class. However, this constructor is also
valid for lvalues (but not rvalues) of reference_wrapper specializations.
This patch fixes this by limiting above optimization only to situations,
when argument is not specialization of reference_wrapper. This is achieved
bu comparing __inv_unwrap<_Td>::type with _Td. We use __inv_unwrap because
unwrap_reference_t does not handle cv-qualified types.
PR libstdc++/121858
libstdc++-v3/ChangeLog:
* include/bits/funcref_impl.h
(function_ref::function_ref(nontype<__fn>, _Up&&)): Handle.
reference_wrapper.
* testsuite/20_util/function_ref/call.cc: Call and update
test05(). Add new test06() for reference_wrapper.
---
v3 only expands test for rebinding.
Tested on x86_64-linux. OK for trunk?
libstdc++-v3/include/bits/funcref_impl.h | 6 +-
.../testsuite/20_util/function_ref/call.cc | 115 +++++++++++++++---
2 files changed, 99 insertions(+), 22 deletions(-)
diff --git a/libstdc++-v3/include/bits/funcref_impl.h
b/libstdc++-v3/include/bits/funcref_impl.h
index 44c992281be..3fe2fb1b3f5 100644
--- a/libstdc++-v3/include/bits/funcref_impl.h
+++ b/libstdc++-v3/include/bits/funcref_impl.h
@@ -138,13 +138,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
if constexpr (is_pointer_v<_Fn> || is_member_pointer_v<_Fn>)
static_assert(__fn != nullptr);
- using _Tr = _Td _GLIBCXX_MOF_CV&;
- if constexpr (is_member_pointer_v<_Fn> && is_lvalue_reference_v<_Tr>)
+ if constexpr (is_member_pointer_v<_Fn>
+ && same_as<_Td, typename __inv_unwrap<_Td>::type>)
// N.B. invoking member pointer on lvalue produces the same effects,
// as invoking it on pointer to that lvalue.
_M_invoke = &_Invoker::template _S_bind_ptr<__fn, _Td
_GLIBCXX_MOF_CV>;
else
- _M_invoke = &_Invoker::template _S_bind_ref<__fn, _Tr>;
+ _M_invoke = &_Invoker::template _S_bind_ref<__fn, _Td
_GLIBCXX_MOF_CV&>;
_M_init(std::addressof(__ref));
}
diff --git a/libstdc++-v3/testsuite/20_util/function_ref/call.cc
b/libstdc++-v3/testsuite/20_util/function_ref/call.cc
index 23253c33ee3..49c6030b221 100644
--- a/libstdc++-v3/testsuite/20_util/function_ref/call.cc
+++ b/libstdc++-v3/testsuite/20_util/function_ref/call.cc
@@ -130,7 +130,6 @@ int callback_ref(ftype& f, int x) { return f(x); }
void
test05()
{
-
function_ref<int(int)> r1(nontype<&callback_ptr>, &twice);
VERIFY( r1(2) == 4 );
function_ref<int(int)> r2(nontype<&callback_ptr>, cube);
@@ -140,27 +139,103 @@ test05()
VERIFY( r3(3) == 6 );
function_ref<int(int)> r4(nontype<&callback_ref>, cube);
VERIFY( r4(3) == 27 );
+}
- // Checks if distinction between reference and pointer
- // is preserved.
- struct F
- {
- static
- int operator()(ftype* f, int x)
- { return f(x) + 1000; }
+void
+test06()
+{
+ struct S {
+ int v;
+ int& m() { return v; }
+ const int& c() const { return v; }
- static
- int operator()(ftype& f, int x)
- { return f(x) + 2000; }
+ int& operator()(int) { return v; }
+ int const& operator()(int, int) const { return v; }
};
- function_ref<int(int)> r5(nontype<F{}>, &twice);
- VERIFY( r5(2) == 1004 );
- function_ref<int(int)> r6(nontype<F{}>, twice);
- VERIFY( r6(2) == 2008 );
- function_ref<int(int)> r7(nontype<F{}>, &cube);
- VERIFY( r7(3) == 1006 );
- function_ref<int(int)> r8(nontype<F{}>, cube);
- VERIFY( r8(3) == 2027 );
+ S s{10};
+ std::reference_wrapper<S> sr(s);
+ std::reference_wrapper<const S> csr(s);
+
+ std::function_ref<int&(int)> e1(sr);
+ VERIFY( &e1(0) == &s.v );
+ std::function_ref<int&(int) const> e2(sr);
+ VERIFY( &e2(0) == &s.v );
+ std::function_ref<int&(int) const> e3(std::as_const(sr));
+ VERIFY( &e3(0) == &s.v );
+
+ std::function_ref<const int&(int, int)> e4(sr);
+ VERIFY( &e4(0, 0) == &s.v );
+ std::function_ref<const int&(int, int) const> e5(sr);
+ VERIFY( &e5(0, 0) == &s.v );
+ std::function_ref<const int&(int, int)> e6(csr);
+ VERIFY( &e6(0, 0) == &s.v );
+ std::function_ref<const int&(int, int) const> e7(csr);
+ VERIFY( &e7(0, 0) == &s.v );
+ std::function_ref<const int&(int, int) const> e8(std::as_const(csr));
+ VERIFY( &e8(0, 0) == &s.v );
+
+ std::function_ref<int&()> f1(std::nontype<&S::v>, sr);
+ VERIFY( &f1() == &s.v );
+ std::function_ref<const int&()> f2(std::nontype<&S::v>, sr);
+ VERIFY( &f2() == &s.v );
+ std::function_ref<int&()> f3(std::nontype<&S::m>, sr);
+ VERIFY( &f3() == &s.v );
+ std::function_ref<const int&()> f4(std::nontype<&S::c>, sr);
+ VERIFY( &f4() == &s.v );
+
+ std::function_ref<const int&()> f5(std::nontype<&S::v>, csr);
+ VERIFY( &f5() == &s.v );
+ std::function_ref<const int&()> f6(std::nontype<&S::c>, sr);
+ VERIFY( &f6() == &s.v );
+ static_assert( !std::is_constructible_v<
+ std::function_ref<int&()>,
+ std::nontype_t<&S::c>, std::reference_wrapper<S>&>
+ );
+
+ std::function_ref<int&()> f7(std::nontype<&S::v>, std::as_const(sr));
+ VERIFY( &f7() == &s.v );
+ std::function_ref<const int&()> f8(std::nontype<&S::m>, std::as_const(sr));
+ VERIFY( &f8() == &s.v );
+
+ // No rvalue reference_wrapper support
+ static_assert( !std::is_constructible_v<
+ std::function_ref<int&()>,
+ std::nontype_t<&S::v>, std::reference_wrapper<S>>
+ );
+ static_assert( !std::is_constructible_v<
+ std::function_ref<int&()>,
+ std::nontype_t<&S::v>, std::reference_wrapper<const S>>
+ );
+
+ // reference to reference_wrapper are bound, so mutation are visible
+ S s2{20};
+ sr = s2;
+ csr = s2;
+ VERIFY( &e1(0) == &s2.v );
+ VERIFY( &e2(0) == &s2.v );
+ VERIFY( &e3(0) == &s2.v );
+ VERIFY( &e4(0, 0) == &s2.v );
+ VERIFY( &e5(0, 0) == &s2.v );
+ VERIFY( &e6(0, 0) == &s2.v );
+ VERIFY( &e7(0, 0) == &s2.v );
+ VERIFY( &e8(0, 0) == &s2.v );
+ VERIFY( &f1() == &s2.v );
+ VERIFY( &f2() == &s2.v );
+ VERIFY( &f3() == &s2.v );
+ VERIFY( &f4() == &s2.v );
+ VERIFY( &f5() == &s2.v );
+ VERIFY( &f6() == &s2.v );
+ VERIFY( &f7() == &s2.v );
+ VERIFY( &f8() == &s2.v );
+
+ constexpr auto id = []<typename T>(const std::reference_wrapper<T>& x)
+ { return &x; };
+
+ // identity of reference_wrapper is preserved
+ std::function_ref<const std::reference_wrapper<S>*()> g1(std::nontype<id>,
sr);
+ VERIFY( g1() == &sr );
+ std::function_ref<const std::reference_wrapper<const S>*()>
g2(std::nontype<id>, csr);
+ VERIFY( g2() == &csr );
}
struct Incomplete;
@@ -182,5 +257,7 @@ int main()
test02();
test03();
test04();
+ test05();
+ test06();
test_params();
}
--
2.51.1
