This optimizes the __format_arg_store type to allow a more efficient
storage of the basic_format_args.
It stores the data in two arrays:
- A struct with the tag of the exposition only variant's type and the
offset of the element in the data array. Since this array only depends
on the type information it's calculated at compile time and can be
shared by different instances of this class.
- The arguments converted to the types used in the exposition only
variant of basic_format_arg. This means the packed data can be
directly copied to an element of this variant.
The new code uses rvalue reference arguments in preparation for P2418.
The handle class also has some changes to prepare for P2418. The real
changed for P2418 will be done separately, but these parts make it
easier to implement that paper.
Some parts of existing test code are removed since they were no longer
valid after the changes, but new tests have been added.
Implements parts of:
- P2418 Add support for std::generator-like types to std::format
Completes:
- LWG3473 Normative encouragement in non-normative note
Depends on D121138
Reviewed By: #libc, vitaut, Mordante
Differential Revision: https://reviews.llvm.org/D121514
The concept is based on P2286R2 Formatting Ranges. It will be used to
optimise the storage of __format_arg_store as required by LWG-3473.
Depends on D120916
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D120921
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.
Differential Revision: https://reviews.llvm.org/D121528
This commit reverts 5aaefa51 (and also partly 7f285f48e7 and b6d75682f9,
which were related to the original commit). As landed, 5aaefa51 had
unintended consequences on some downstream bots and didn't have proper
coverage upstream due to a few subtle things. Implementing this is
something we should do in libc++, however we'll first need to address
a few issues listed in https://reviews.llvm.org/D106124#3349710.
Differential Revision: https://reviews.llvm.org/D120683
libc++ has started splicing standard library headers into much more
fine-grained content for maintainability. It's very likely that outdated
and naive tooling (some of which is outside of LLVM's scope) will
suggest users include things such as <__ranges/access.h> instead of
<ranges>, and Hyrum's law suggests that users will eventually begin to
rely on this without the help of tooling. As such, this commit
intends to protect users from themselves, by making it a hard error for
anyone outside of the standard library to include libc++ detail headers.
Differential Revision: https://reviews.llvm.org/D106124
This implements the struct `__format_arg_store` and its dependencies:
* the class basic_format_arg,
* the class basic_format_args,
* the class basic_format_context,
* the function make_format_args,
* the function wmake_format_args,
* the function visit_format_arg,
* several Standard required typedefs.
The following parts will be implemented in a later patch:
* the child class `basic_format_arg::handle`,
* the function `basic_format_arg::basic_format_arg(const T* p)`.
The following extension has been implemented:
* the class basic_format_arg supports `__[u]int128_t` on platform where libc++ supports 128 bit integrals.
Implements parts of:
* P0645 Text Formatting
Completes:
* LWG3371 visit_format_arg and make_format_args are not hidden friends
* LWG3542 basic_format_arg mishandles basic_string_view with custom traits
Note https://mordante.github.io/blog/2021/06/05/format.html gives a bit more information about the goals and non-goals of this initial patch series.
Reviewed By: #libc, ldionne, vitaut
Differential Revision: https://reviews.llvm.org/D103357
Mark de Wever