Pushed to trunk now. Backport to gcc-14 needed too.
On Thu, 20 Jun 2024 at 16:27, Jonathan Wakely <jwak...@redhat.com> wrote:
>
> This unfortunately means we can never increase __cpp_lib_chrono again
> for the old string ABI, but I don't see any alternative (except
> supporting chrono::tzdb for the old string, which will be a lot of work
> that I don't want to do!)
>
> -- >8 --
>
> The <chrono> header is incomplete for the old std::string ABI, because
> std::chrono::tzdb is only defined for the new ABI. The feature test
> macro advertising full C++20 support should not be defined for the old
> ABI.
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/version.def (chrono): Add cxx11abi = yes.
> * include/bits/version.h: Regenerate.
> * testsuite/std/time/syn_c++20.cc: Adjust expected value for
> the feature test macro.
> ---
> libstdc++-v3/include/bits/version.def | 1 +
> libstdc++-v3/include/bits/version.h | 2 +-
> libstdc++-v3/testsuite/std/time/syn_c++20.cc | 11 +++++++++--
> 3 files changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/libstdc++-v3/include/bits/version.def
> b/libstdc++-v3/include/bits/version.def
> index 683b967d54b..42cdef2f526 100644
> --- a/libstdc++-v3/include/bits/version.def
> +++ b/libstdc++-v3/include/bits/version.def
> @@ -574,6 +574,7 @@ ftms = {
> v = 201907;
> cxxmin = 20;
> hosted = yes;
> + cxx11abi = yes; // std::chrono::tzdb requires cxx11 std::string
> };
> values = {
> v = 201611;
> diff --git a/libstdc++-v3/include/bits/version.h
> b/libstdc++-v3/include/bits/version.h
> index 4850041c0a3..1eaf3733bc2 100644
> --- a/libstdc++-v3/include/bits/version.h
> +++ b/libstdc++-v3/include/bits/version.h
> @@ -639,7 +639,7 @@
> #undef __glibcxx_want_boyer_moore_searcher
>
> #if !defined(__cpp_lib_chrono)
> -# if (__cplusplus >= 202002L) && _GLIBCXX_HOSTED
> +# if (__cplusplus >= 202002L) && _GLIBCXX_USE_CXX11_ABI && _GLIBCXX_HOSTED
> # define __glibcxx_chrono 201907L
> # if defined(__glibcxx_want_all) || defined(__glibcxx_want_chrono)
> # define __cpp_lib_chrono 201907L
> diff --git a/libstdc++-v3/testsuite/std/time/syn_c++20.cc
> b/libstdc++-v3/testsuite/std/time/syn_c++20.cc
> index f0b86199e9d..4a527262e9d 100644
> --- a/libstdc++-v3/testsuite/std/time/syn_c++20.cc
> +++ b/libstdc++-v3/testsuite/std/time/syn_c++20.cc
> @@ -20,9 +20,16 @@
>
> #include <chrono>
>
> +// std::chrono::tzdb is not defined for the old std::string ABI.
> +#if _GLIBCXX_USE_CXX_ABI
> +# define EXPECTED_VALUE 201907L
> +#else
> +# define EXPECTED_VALUE 201611L
> +#endif
> +
> #ifndef __cpp_lib_chrono
> # error "Feature test macro for chrono is missing in <chrono>"
> -#elif __cpp_lib_chrono < 201907L
> +#elif __cpp_lib_chrono < EXPECTED_VALUE
> # error "Feature test macro for chrono has wrong value in <chrono>"
> #endif
>
> @@ -94,7 +101,7 @@ namespace __gnu_test
> using std::chrono::make12;
> using std::chrono::make24;
>
> -#if _GLIBCXX_USE_CXX11_ABI
> +#if __cpp_lib_chrono >= 201803L
> using std::chrono::tzdb;
> using std::chrono::tzdb_list;
> using std::chrono::get_tzdb;
> --
> 2.45.2
>
