From 33de0ffcf050e581eb931eb4f1c5ad9c0cdc6bf6 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Tue, 18 Oct 2022 20:49:42 +0100 Subject: libstdc++: Fix std::move_only_function for incomplete parameter types The std::move_only_function::__param_t alias template attempts to optimize argument passing for the invoker, by passing by rvalue reference for types that are non-trivial or large. However, the precondition for is_trivally_copyable makes it unsuitable for using here, and can cause ODR violations. Just use is_scalar instead, and pass all class types (even small, trivial ones) by value. libstdc++-v3/ChangeLog: * include/bits/mofunc_impl.h (move_only_function::__param_t): Use __is_scalar instead of is_trivially_copyable. * testsuite/20_util/move_only_function/call.cc: Check parameters involving incomplete types. --- libstdc++-v3/include/bits/mofunc_impl.h | 5 +---- libstdc++-v3/testsuite/20_util/move_only_function/call.cc | 11 +++++++++++ 2 files changed, 12 insertions(+), 4 deletions(-) (limited to 'libstdc++-v3') diff --git a/libstdc++-v3/include/bits/mofunc_impl.h b/libstdc++-v3/include/bits/mofunc_impl.h index 405c405..47e1e50 100644 --- a/libstdc++-v3/include/bits/mofunc_impl.h +++ b/libstdc++-v3/include/bits/mofunc_impl.h @@ -205,10 +205,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION private: template - using __param_t - = __conditional_t - && sizeof(_Tp) <= sizeof(long), - _Tp, _Tp&&>; + using __param_t = __conditional_t, _Tp, _Tp&&>; using _Invoker = _Res (*)(_Mofunc_base _GLIBCXX_MOF_CV*, __param_t<_ArgTypes>...) noexcept(_Noex); diff --git a/libstdc++-v3/testsuite/20_util/move_only_function/call.cc b/libstdc++-v3/testsuite/20_util/move_only_function/call.cc index 68aa205..3e15983 100644 --- a/libstdc++-v3/testsuite/20_util/move_only_function/call.cc +++ b/libstdc++-v3/testsuite/20_util/move_only_function/call.cc @@ -191,10 +191,21 @@ test04() VERIFY( std::move(std::as_const(f5))() == 3 ); } +struct Incomplete; + +void +test_params() +{ + std::move_only_function f1; + std::move_only_function f2; + std::move_only_function f3; +} + int main() { test01(); test02(); test03(); test04(); + test_params(); } -- cgit v1.1