Add support for _BitInt on clang #4072

Arghnews · 2024-07-13T18:09:44Z

Only enabled for clang >= 14 as that's all that supports _BitInt at the moment

We need a forwarding reference for map to be a "more specialized" match; const T&, T etc. are ambiguous.

I'm not too familiar, would there be a better way to do this by adding an entry into enum class type for _BitInts? Or this is fine?

Fyi this worked in version 9 because of this catch-all overload:

fmt/include/fmt/core.h

Lines 1506 to 1516 in a337011

    
           template <typename T, typename U = remove_cvref_t<T>, 
        
                     FMT_ENABLE_IF(!is_string<U>::value && !is_char<U>::value && 
        
                                   !std::is_array<U>::value && 
        
                                   !std::is_pointer<U>::value && 
        
                                   !has_format_as<U>::value && 
        
                                   (has_formatter<U, Context>::value || 
        
                                    has_fallback_formatter<U, char_type>::value))> 
        
           FMT_CONSTEXPR FMT_INLINE auto map(T&& val) 
        
               -> decltype(this->do_map(std::forward<T>(val))) { 
        
             return do_map(std::forward<T>(val)); 
        
           }

Which was then subsequently narrowed down to extended FP types (which "broke" the accidental support for this):

fmt/include/fmt/base.h

Lines 1527 to 1537 in 6a192f8

    
           // is_fundamental is used to allow formatters for extended FP types. 
        
           template <typename T, typename U = remove_const_t<T>, 
        
                     FMT_ENABLE_IF( 
        
                         (std::is_class<U>::value || std::is_enum<U>::value || 
        
                          std::is_union<U>::value || std::is_fundamental<U>::value) && 
        
                         !has_to_string_view<U>::value && !is_char<U>::value && 
        
                         !is_named_arg<U>::value && !std::is_integral<U>::value && 
        
                         !std::is_arithmetic<format_as_t<U>>::value)> 
        
           FMT_MAP_API auto map(T& val) -> decltype(FMT_DECLTYPE_THIS do_map(val)) { 
        
             return do_map(val); 
        
           }

include/fmt/base.h

vitaut

Thanks for the PR!

include/fmt/base.h

test/format-test.cc

include/fmt/base.h

vitaut · 2024-07-27T18:40:29Z

@Arghnews, do you plan to update this PR or shall we close it for now (can be reopened later)?

Arghnews · 2024-07-27T22:25:45Z

@Arghnews, do you plan to update this PR or shall we close it for now (can be reopened later)?

@vitaut Hi, sorry been busy and now I'm on holiday for 2 weeks, but will update once back and implement your feedback. I'd say leave it open and I'll update in 2-3 weeks, but it's up to you (can reopen of course). Cheers!

vitaut · 2024-07-27T23:41:33Z

No hurry. Let's keep it open and enjoy your holiday!

Arghnews · 2024-08-26T14:09:59Z

Hi,

Reworked this so that now fmtlib will format _BitInts up to 128 bits

Uses wider formatter ie. integer types are widened to 64bit if <= 64 bits wide (assume this is acceptable for performance)
If FMT_USE_INT128 then supports up to 128 bits

Can't write static_assert(fmt::is_formattable<signed_bitint<129>, char>{}, ""); as apple clang only allows up to 128 bits. BITINT_MAXWIDTH isn't defined, could check __apple_build_version__ but I just removed this test

Let me know any feedback @vitaut

vitaut

A few more comments.

include/fmt/base.h

include/fmt/format.h

test/format-test.cc

vitaut · 2024-08-28T22:00:18Z

include/fmt/format.h

+  using type = conditional_t<
+      N <= 64, conditional_t<is_signed, int64_t, uint64_t>,
+      conditional_t<(N > 64 && N <= 128),
+                    conditional_t<is_signed, __int128, unsigned __int128>,
+                    void>>;


I think this can be moved to bitint_traits which would make number_of_bits and is_signed unnecessary.

I think this can be moved to bitint_traits which would make number_of_bits and is_signed unnecessary.

Nice suggestion, have done. Only thing to note, we must #include <cstdint> in base.h now, for the int64_t, if this is acceptable. This was already included in format.h

Let's use (unsigned) long long which is guaranteed to be at least 64-bit and avoid additional include.

Let's use (unsigned) long long which is guaranteed to be at least 64-bit and avoid additional include.

Good shout, have made this change

Issue fmtlib#4007 Make _BitInt up to 128bits formattable Note, libstdc++ is_signed doesn't work with _BitInt (so use own)

vitaut · 2024-08-29T01:57:58Z

Merged, thanks!

@timsong-cpp

- Update from version 11.0.2 to 11.1.3 - Update of rootfile - Changelog 11.1.3 - Fixed compilation on GCC 9.4 (fmtlib/fmt#4313). - Worked around an internal compiler error when using C++20 modules with GCC 14.2 and earlier (fmtlib/fmt#4295). - Worked around a bug in GCC 6 (fmtlib/fmt#4318). - Fixed an issue caused by instantiating `formatter<const T>` (fmtlib/fmt#4303, fmtlib/fmt#4325). Thanks @timsong-cpp. - Fixed formatting into `std::ostreambuf_iterator` when using format string compilation (fmtlib/fmt#4309, fmtlib/fmt#4312). Thanks @phprus. - Restored a constraint on the map formatter so that it correctly reports as unformattable when the element is (fmtlib/fmt#4326). Thanks @timsong-cpp. - Reduced the size of format specs (fmtlib/fmt#4298). - Readded `args()` to `fmt::format_context` (fmtlib/fmt#4307, fmtlib/fmt#4310). Thanks @Erroneous1. - Fixed a bogus MSVC warning (fmtlib/fmt#4314, fmtlib/fmt#4322). Thanks @ZehMatt. - Fixed a pedantic mode error in the CMake config (fmtlib/fmt#4327). Thanks @rlalik. 11.1.2 - Fixed ABI compatibility with earlier 11.x versions (fmtlib/fmt#4292). - Added `wchar_t` support to the `std::bitset` formatter (fmtlib/fmt#4285, fmtlib/fmt#4286, fmtlib/fmt#4289, fmtlib/fmt#4290). Thanks @phprus. - Prefixed CMake components with `fmt-` to simplify usage of {fmt} via `add_subdirectory` (fmtlib/fmt#4283). - Updated docs for meson (fmtlib/fmt#4291). Thanks @trim21. - Fixed a compilation error in chrono on nvcc (fmtlib/fmt#4297, fmtlib/fmt#4301). Thanks @breyerml. - Fixed various warnings (fmtlib/fmt#4288, fmtlib/fmt#4299). Thanks @GamesTrap and @edo9300. 11.1.1 - Fixed ABI compatibility with earlier 11.x versions (fmtlib/fmt#4278). - Defined CMake components (`core` and `doc`) to allow docs to be installed separately (fmtlib/fmt#4276). Thanks @carlsmedstad. 11.1.0 - Improved C++20 module support (fmtlib/fmt#4081, fmtlib/fmt#4083, fmtlib/fmt#4084, fmtlib/fmt#4152, fmtlib/fmt#4153, fmtlib/fmt#4169, fmtlib/fmt#4190, fmtlib/fmt#4234, fmtlib/fmt#4239). Thanks @kamrann and @Arghnews. - Reduced debug (unoptimized) binary code size and the number of template instantiations when passing formatting arguments. For example, unoptimized binary code size for `fmt::print("{}", 42)` was reduced by ~40% on GCC and ~60% on clang (x86-64). GCC: - Before: 161 instructions of which 105 are in reusable functions ([godbolt](https://www.godbolt.org/z/s9bGoo4ze)). - After: 116 instructions of which 60 are in reusable functions ([godbolt](https://www.godbolt.org/z/r7GGGxMs6)). Clang: - Before: 310 instructions of which 251 are in reusable functions ([godbolt](https://www.godbolt.org/z/Ts88b7M9o)). - After: 194 instructions of which 135 are in reusable functions ([godbolt](https://www.godbolt.org/z/vcrjP8ceW)). - Added an experimental `fmt::writer` API that can be used for writing to different destinations such as files or strings (fmtlib/fmt#2354). For example ([godbolt](https://www.godbolt.org/z/rWoKfbP7e)): ```c++ #include <fmt/os.h> void write_text(fmt::writer w) { w.print("The answer is {}.", 42); } int main() { // Write to FILE. write_text(stdout); // Write to fmt::ostream. auto f = fmt::output_file("myfile"); write_text(f); // Write to std::string. auto sb = fmt::string_buffer(); write_text(sb); std::string s = sb.str(); } ``` - Added width and alignment support to the formatter of `std::error_code`. - Made `std::expected<void, E>` formattable (fmtlib/fmt#4145, fmtlib/fmt#4148). For example ([godbolt](https://www.godbolt.org/z/hrj5c6G86)): ```c++ fmt::print("{}", std::expected<void, int>()); ``` prints ``` expected() ``` Thanks @phprus. - Made `fmt::is_formattable<void>` SFINAE-friendly (fmtlib/fmt#4147). - Added support for `_BitInt` formatting when using clang (fmtlib/fmt#4007, fmtlib/fmt#4072, fmtlib/fmt#4140, fmtlib/fmt#4173, fmtlib/fmt#4176). For example ([godbolt](https://www.godbolt.org/z/KWjbWec5z)): ```c++ using int42 = _BitInt(42); fmt::print("{}", int42(100)); ``` Thanks @Arghnews. - Added the `n` specifier for tuples and pairs (fmtlib/fmt#4107). Thanks @someonewithpc. - Added support for tuple-like types to `fmt::join` (fmtlib/fmt#4226, fmtlib/fmt#4230). Thanks @phprus. - Made more types formattable at compile time (fmtlib/fmt#4127). Thanks @AnthonyVH. - Implemented a more efficient compile-time `fmt::formatted_size` (fmtlib/fmt#4102, fmtlib/fmt#4103). Thanks @phprus. - Fixed compile-time formatting of some string types (fmtlib/fmt#4065). Thanks @torshepherd. - Made compiled version of `fmt::format_to` work with `std::back_insert_iterator<std::vector<char>>` (fmtlib/fmt#4206, fmtlib/fmt#4211). Thanks @phprus. - Added a formatter for `std::reference_wrapper` (fmtlib/fmt#4163, fmtlib/fmt#4164). Thanks @yfeldblum and @phprus. - Added experimental padding support (glibc `strftime` extension) to `%m`, `%j` and `%Y` (fmtlib/fmt#4161). Thanks @KKhanhH. - Made microseconds formatted as `us` instead of `µs` if the Unicode support is disabled (fmtlib/fmt#4088). - Fixed an unreleased regression in transcoding of surrogate pairs (fmtlib/fmt#4094, fmtlib/fmt#4095). Thanks @phprus. - Made `fmt::appender` satisfy `std::output_iterator` concept (fmtlib/fmt#4092, fmtlib/fmt#4093). Thanks @phprus. - Made `std::iterator_traits<fmt::appender>` standard-conforming (fmtlib/fmt#4185). Thanks @CaseyCarter. - Made it easier to reuse `fmt::formatter<std::string_view>` for types with an implicit conversion to `std::string_view` (fmtlib/fmt#4036, fmtlib/fmt#4055). Thanks @Arghnews. - Made it possible to disable `<filesystem>` use via `FMT_CPP_LIB_FILESYSTEM` for compatibility with some video game console SDKs, e.g. Nintendo Switch SDK (fmtlib/fmt#4257, fmtlib/fmt#4258, fmtlib/fmt#4259). Thanks @W4RH4WK and @phprus. - Fixed compatibility with platforms that use 80-bit `long double` (fmtlib/fmt#4245, fmtlib/fmt#4246). Thanks @jsirpoma. - Added support for UTF-32 code units greater than `0xFFFF` in fill (fmtlib/fmt#4201). - Fixed handling of legacy encodings on Windows with GCC (fmtlib/fmt#4162). - Made `fmt::to_string` take `fmt::basic_memory_buffer` by const reference (fmtlib/fmt#4261, fmtlib/fmt#4262). Thanks @sascha-devel. - Added `fmt::dynamic_format_arg_store::size` (fmtlib/fmt#4270). Thanks @hannes-harnisch. - Removed the ability to control locale usage via an undocumented `FMT_STATIC_THOUSANDS_SEPARATOR` in favor of `FMT_USE_LOCALE`. - Renamed `FMT_EXCEPTIONS` to `FMT_USE_EXCEPTIONS` for consistency with other similar macros. - Improved include directory ordering to reduce the chance of including incorrect headers when using multiple versions of {fmt} (fmtlib/fmt#4116). Thanks @cdzhan. - Made it possible to compile a subset of {fmt} without the C++ runtime. - Improved documentation and README (fmtlib/fmt#4066, fmtlib/fmt#4117, fmtlib/fmt#4203, fmtlib/fmt#4235). Thanks @zyctree and @nikola-sh. - Improved the documentation generator (fmtlib/fmt#4110, fmtlib/fmt#4115). Thanks @rturrado. - Improved CI (fmtlib/fmt#4155, fmtlib/fmt#4151). Thanks @phprus. - Fixed various warnings and compilation issues (fmtlib/fmt#2708, fmtlib/fmt#4091, fmtlib/fmt#4109, fmtlib/fmt#4113, fmtlib/fmt#4125, fmtlib/fmt#4129, fmtlib/fmt#4130, fmtlib/fmt#4131, fmtlib/fmt#4132, fmtlib/fmt#4133, fmtlib/fmt#4144, fmtlib/fmt#4150, fmtlib/fmt#4158, fmtlib/fmt#4159, fmtlib/fmt#4160, fmtlib/fmt#4170, fmtlib/fmt#4177, fmtlib/fmt#4187, fmtlib/fmt#4188, fmtlib/fmt#4194, fmtlib/fmt#4200, fmtlib/fmt#4205, fmtlib/fmt#4207, fmtlib/fmt#4208, fmtlib/fmt#4210, fmtlib/fmt#4220, fmtlib/fmt#4231, fmtlib/fmt#4232, fmtlib/fmt#4233, fmtlib/fmt#4236, fmtlib/fmt#4267, fmtlib/fmt#4271). Thanks @torsten48, @Arghnews, @tinfoilboy, @aminya, @Ottani, @zeroomega, @c4v4, @kongy, @vinayyadav3016, @sergio-nsk, @phprus and @YexuanXiao. Signed-off-by: Adolf Belka <[email protected]> Signed-off-by: Michael Tremer <[email protected]>

Arghnews force-pushed the support_bitint branch 3 times, most recently from 903edfd to 3666cee Compare July 13, 2024 18:35

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Arghnews force-pushed the support_bitint branch 2 times, most recently from 7322e2c to d8ad099 Compare August 26, 2024 14:00

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Arghnews force-pushed the support_bitint branch from d8ad099 to df02f20 Compare August 28, 2024 21:54

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Arghnews force-pushed the support_bitint branch from df02f20 to 1191f39 Compare August 28, 2024 23:46

Add support for _BitInt on clang

d32293c

Issue fmtlib#4007 Make _BitInt up to 128bits formattable Note, libstdc++ is_signed doesn't work with _BitInt (so use own)

Arghnews force-pushed the support_bitint branch from 1191f39 to d32293c Compare August 29, 2024 00:13

vitaut approved these changes Aug 29, 2024

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vitaut merged commit 5a0a373 into fmtlib:master Aug 29, 2024
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vitaut mentioned this pull request Aug 29, 2024

Error when formatting _BitInt #4007

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Add support for _BitInt on clang #4072

Add support for _BitInt on clang #4072

Arghnews commented Jul 13, 2024

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vitaut Aug 28, 2024

Arghnews Aug 28, 2024 •

edited

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vitaut Aug 29, 2024

Arghnews Aug 29, 2024

vitaut commented Aug 29, 2024

	template <typename T, typename U = remove_cvref_t<T>,
	FMT_ENABLE_IF(!is_string<U>::value && !is_char<U>::value &&
	!std::is_array<U>::value &&
	!std::is_pointer<U>::value &&
	!has_format_as<U>::value &&
	(has_formatter<U, Context>::value \|\|
	has_fallback_formatter<U, char_type>::value))>
	FMT_CONSTEXPR FMT_INLINE auto map(T&& val)
	-> decltype(this->do_map(std::forward<T>(val))) {
	return do_map(std::forward<T>(val));
	}

	// is_fundamental is used to allow formatters for extended FP types.
	template <typename T, typename U = remove_const_t<T>,
	FMT_ENABLE_IF(
	(std::is_class<U>::value \|\| std::is_enum<U>::value \|\|
	std::is_union<U>::value \|\| std::is_fundamental<U>::value) &&
	!has_to_string_view<U>::value && !is_char<U>::value &&
	!is_named_arg<U>::value && !std::is_integral<U>::value &&
	!std::is_arithmetic<format_as_t<U>>::value)>
	FMT_MAP_API auto map(T& val) -> decltype(FMT_DECLTYPE_THIS do_map(val)) {
	return do_map(val);
	}

Add support for _BitInt on clang #4072

Add support for _BitInt on clang #4072

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