This patch removes the base template implementation for std::char_traits.
If my reading of http://eel.is/c++draft/char.traits is correct, the
Standard mandates that the library provides specializations for several
types like char and wchar_t, but not any implementation in the base
template. Indeed, such an implementation is bound to be incorrect for
most types anyways, since things like `eof()` and `int_type` will definitely
have to be customized.
Since the base template implementation should not have worked for anyone,
this shouldn't be a breaking change (I expect that anyone defining a
custom character type today will already have to provide their own
specialization of char_traits). However, since we're aware of some users
of char_traits for unsigned char and signed char, we're keeping those two
specializations around for two releases to give people some time to migrate.
Differential Revision: https://reviews.llvm.org/D138307
compressed_pair is widely used in the library, but most of the uses don't use the tuple parts. To avoid including <tuple> everywhere, use the forward declaration instead in compressed_pair.h
Reviewed By: ldionne, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D133331
This was discussed on Discord with the consensus that we should rename the macros.
Reviewed By: ldionne, Mordante, var-const, avogelsgesang, jloser, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D131498
As a fly-by fix, also move it closer to where it is needed, and add a
comment explaining the existence of this weird function.
Differential Revision: https://reviews.llvm.org/D121231
Move `__quoted_output_proxy` into the one file that uses it.
A `const char*` has no associated traits class, so `std::quoted("literal")`
should be printable into any basic_ostream regardless of traits.
Use hidden-friend `operator<<` and `operator>>`, since we're permitted to.
(The exact signature is unspecified because the class itself is unspecified.)
We shouldn't support `std::quoted("literal")` in C++03 or C++11 mode.
(We do need `std::__quoted(s)` and `std::__quoted(cs)` in C++11 mode,
because they're used by `std::__fs::filesystem::path`.)
Differential Revision: https://reviews.llvm.org/D120135
Notably the following ctors remain non-explicit because they
are used as implicit conversions in too many places:
* __debug_less(_Compare&)
* __map_iterator(_TreeIterator)
* __map_const_iterator(_TreeIterator)
* __hash_map_iterator(_HashIterator)
* __hash_map_const_iterator(_HashIterator)
Differential Revision: https://reviews.llvm.org/D119894
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 is the first step towards disentangling the debug mode and assertions
in libc++. This patch doesn't make any functional change: it simply moves
_LIBCPP_ASSERT-related stuff to its own file so as to make it clear that
libc++ assertions and the debug mode are different things. Future patches
will make it possible to enable assertions without enabling the debug
mode.
Differential Revision: https://reviews.llvm.org/D119769
The NFC part of D116809. We still want to enforce this in CI,
but the mechanism for that is still to-be-determined.
Differential Revision: https://reviews.llvm.org/D116809
Allow `__move_constexpr` to work with unrelated pointers and `_LIBCPP_ASSERT` that `__copy_constexpr`, `__move_constexpr` and `__assign_constexpr` are only run during constant evaluation
Reviewed By: ldionne, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D115986
GCC currently does not allow `__builtin_strlen()` during constant evaluation. This PR adds a workaround in `std::char_traits<char>::length()`
Reviewed By: Quuxplusone, ldionne, #libc, Mordante
Spies: Mordante, libcxx-commits
Differential Revision: https://reviews.llvm.org/D115795
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
Some embedded platforms do not wish to support the C library functionality
for handling wchar_t because they have no use for it. It makes sense for
libc++ to work properly on those platforms, so this commit adds a carve-out
of functionality for wchar_t.
Unfortunately, unlike some other carve-outs (e.g. random device), this
patch touches several parts of the library. However, despite the wide
impact of this patch, I still think it is important to support this
configuration since it makes it much simpler to port libc++ to some
embedded platforms.
Differential Revision: https://reviews.llvm.org/D111265
Now that __builtin_is_constant_evaluated() is present on all supported
compilers, we can use it to skip the UB-inducing assert in cases where
the computation might be happening at constexpr time.
Differential Revision: https://reviews.llvm.org/D101674
Left to finish P0482:
* <cuchar> header.
* Parts of <memory_resource> concerning char8_t. Also, tests for hash<pmr::*string>.
Reviewed By: ldionne, #libc, Quuxplusone
Differential Revision: https://reviews.llvm.org/D99184
Adds `noexcept` to `string_view`/`string::find` and similar members
(`rfind`, etc.). See discussion in D95251. Refs D95821.
Reviewed By: curdeius, ldionne
Differential Revision: https://reviews.llvm.org/D95848
Generally these calls aren't vulnerable to ADL because they involve only
primitive types. The ones in <list> and <vector> drag in namespace std
but that's OK; the ones in <fstream> and <strstream> are vulnerable
iff `CharT` is an enum type, which seems far-fetched.
But absolutely zero of them *need* ADL to happen; so in my opinion
they should all be consistently qualified, just like calls to any
other (non-user-customizable) functions in namespace std.
Also: Include <cstring> and <cwchar> in <__string>.
We seemed to be getting lucky that <memory> included <iterator>
included <iosfwd> included <wchar.h>. That gave us the
global-namespace `wmemmove`, but not `_VSTD::wmemmove`.
This is now fixed.
I didn't touch these headers:
<ext/__hash> uses strlen, safely
<support/ibm/locale_mgmt_aix.h> uses memcpy, safely
<string.h> uses memchr and strchr, safely
<wchar.h> uses wcschr, safely
<__bsd_locale_fallbacks.h> uses wcsnrtombs, safely
Differential Revision: https://reviews.llvm.org/D93061
I used a lot of `git grep` to find places where `std::` was being used
outside of comments and assert-messages. There were three outcomes:
- Qualified function calls, e.g. `std::move` becomes `_VSTD::move`.
This is the most common case.
- Typenames that don't need qualification, e.g. `std::allocator` becomes `allocator`.
Leaving these as `_VSTD::allocator` would also be fine, but I decided
that removing the qualification is more consistent with existing practice.
- Names that specifically need un-versioned `std::` qualification,
or that I wasn't sure about. For example, I didn't touch any code in
<atomic>, <math.h>, <new>, or any ext/ or experimental/ headers;
and I didn't touch any instances of `std::type_info`.
In some deduction guides, we were accidentally using `class Alloc = typename std::allocator<T>`,
despite `std::allocator<T>`'s type-ness not being template-dependent.
Because `std::allocator` is a qualified name, this did parse as we intended;
but what we meant was simply `class Alloc = allocator<T>`.
Differential Revision: https://reviews.llvm.org/D92250
Zoe Carver says: "We decided that libc++ only supports C++20 constexpr algorithms
when `is_constant_evaluated` is also supported. Here's a link to the discussion."
https://reviews.llvm.org/D65721#inline-735682
Remove _LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED from tests, too.
See Louis's 5911e6a885 if needed to fix bots.
I've applied `UNSUPPORTED: clang-8` preemptively to the altered tests;
I don't know for sure that this was needed, because no clang-8 buildbots
are triggered on pull requests.
Summary: We discovered that the compiler may chose not to inline the operator=, which leads to an expensive extra stack frame. This change makes __assign_no_alias always tail called.
Reviewers: EricWF, #libc!
Subscribers: libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D77913
Summary:
This is a recommit of https://reviews.llvm.org/D73223 where the added function accidentally ended up inside an idef block.
This change splits the copy constructor up inlining short initialization, and explicitly outlining long initialization into __init_copy_ctor_external() which is the externally instantiated slow path.
For unstable ABI, this has the following changes:
remove basic_string(const basic_string&)
remove basic_string(const basic_string&, const Allocator&)
add __init_copy_ctor_external(const value_type*, size_type)
Quick local benchmark for Copy:
Master
```
---------------------------------------------------------------
Benchmark Time CPU Iterations
---------------------------------------------------------------
BM_StringCopy_Empty 3.50 ns 3.51 ns 199326720
BM_StringCopy_Small 3.50 ns 3.51 ns 199510016
BM_StringCopy_Large 15.7 ns 15.7 ns 45230080
BM_StringCopy_Huge 1503 ns 1503 ns 464896
```
With this change
```
---------------------------------------------------------------
Benchmark Time CPU Iterations
---------------------------------------------------------------
BM_StringCopy_Empty 1.99 ns 2.00 ns 356471808
BM_StringCopy_Small 3.29 ns 3.30 ns 203425792
BM_StringCopy_Large 13.3 ns 13.3 ns 52948992
BM_StringCopy_Huge 1472 ns 1472 ns 475136
```
Subscribers: libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D75639
Louis Dionne