[libc++][C++03] Use `__cxx03/` headers in C++03 mode (#109002)

This patch implements the forwarding to frozen C++03 headers as
discussed in
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-

[libc++][C++03] Use `__cxx03/` headers in C++03 mode (#109002)

This patch implements the forwarding to frozen C++03 headers as
discussed in
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc. In the
RFC, we initially proposed selecting the right headers from the Clang
driver, however consensus seemed to steer towards handling this in the
library itself. This patch implements that direction.

At a high level, the changes basically amount to making each public
header look like this:

```
// inside <vector>
#ifdef _LIBCPP_CXX03_LANG
# include <__cxx03/vector>
#else
// normal <vector> content
#endif
```

In most cases, public headers are simple umbrella headers so there isn't
much code in the #else branch. In other cases, the #else branch contains
the actual implementation of the header.

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[libc++] Add #if 0 block to all the top-level headers (#119234)

Including The frozen C++03 headers results in a lot of formatting
changes in the main headers, so this splits these changes into a
sep

[libc++] Add #if 0 block to all the top-level headers (#119234)

Including The frozen C++03 headers results in a lot of formatting
changes in the main headers, so this splits these changes into a
separate commit instead.

This is part of
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc.

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[libc++][modules] Modularize <cstddef> (#107254)

Many headers include `<cstddef>` just for size_t, and pulling in
additional content (e.g. the traits used for std::byte) is unnecessary.
To solve t

[libc++][modules] Modularize <cstddef> (#107254)

Many headers include `<cstddef>` just for size_t, and pulling in
additional content (e.g. the traits used for std::byte) is unnecessary.
To solve this problem, this patch splits up `<cstddef>` into
subcomponents so that headers can include only the parts that they
actually require.

This has the added benefit of making the modules build a lot stricter
with respect to IWYU, and also providing a canonical location where we
define `std::size_t` and friends (which were previously defined in
multiple headers like `<cstddef>` and `<ctime>`).

After this patch, there's still many places in the codebase where we
include `<cstddef>` when `<__cstddef/size_t.h>` would be sufficient.
This patch focuses on removing `<cstddef>` includes from __type_traits
to make these headers non-circular with `<cstddef>`. Additional
refactorings can be tackled separately.

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[libc++] Clean up includes of <__assert> (#80091)

Originally, we used __libcpp_verbose_abort to handle assertion failures.
That function was declared from all public headers. Since we don't use
th

[libc++] Clean up includes of <__assert> (#80091)

Originally, we used __libcpp_verbose_abort to handle assertion failures.
That function was declared from all public headers. Since we don't use
that mechanism anymore, we don't need to declare __libcpp_verbose_abort
from all public headers, and we can clean up a lot of unnecessary
includes.

This patch also moves the definition of the various assertion categories
to the <__assert> header, since we now rely on regular IWYU for these
assertion macros.

rdar://105510916

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[libc++] Move constexpr <cstring> functions into their own headers and remove unused <cstring> includes

Reviewed By: ldionne, Mordante, #libc, #libc_abi

Spies: libcxx-commits

Differential Revision

[libc++] Move constexpr <cstring> functions into their own headers and remove unused <cstring> includes

Reviewed By: ldionne, Mordante, #libc, #libc_abi

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D143329

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[libc++] Refactor char_traits

This allows us to reuse workarounds for compilers that don't provide the builtins or constexpr support.

Reviewed By: ldionne, Mordante, #libc

Spies: libcxx-commits

D

[libc++] Refactor char_traits

This allows us to reuse workarounds for compilers that don't provide the builtins or constexpr support.

Reviewed By: ldionne, Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D139555

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[libc++] Diagnose when header search paths are set up incorrectly

An issue I often see in codebases compiled for unusual platforms is
that header search paths are specified manually and are subtly w

[libc++] Diagnose when header search paths are set up incorrectly

An issue I often see in codebases compiled for unusual platforms is
that header search paths are specified manually and are subtly wrong.
For example, people will manually add `-isystem <some-toolchain>/usr/include`,
which ends up messing up the layering of header search paths required by
libc++ (because the C Standard Library now appears *before* libc++ in
the search paths). Without this patch, this will end up causing
compilation errors that are pretty inscrutable. This patch aims to
improve the user experience by diagnosing this issue explicitly.

In all cases I can think of, I would expect that a compilation error
occur if these header search paths are not layered properly. This
should only provide an explicit diagnostic instead of failing due
to seemingly unrelated compilation errors.

Differential Revision: https://reviews.llvm.org/D131441

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[libc++] Ensure that all public C++ headers include <__assert>

This patch changes the requirement for getting the declaration of the
assertion handler from including <__assert> to including any publ

[libc++] Ensure that all public C++ headers include <__assert>

This patch changes the requirement for getting the declaration of the
assertion handler from including <__assert> to including any public
C++ header of the library. Note that C compatibility headers are
excluded because we don't implement all the C headers ourselves --
some of them are taken straight from the C library, like assert.h.

It also adds a generated test to check it. Furthermore, this new
generated test is designed in a way that will make it possible to
replace almost all the existing test-generation scripts with this
system in upcoming patches.

Differential Revision: https://reviews.llvm.org/D122506

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[libc++] Normalize all our '#pragma GCC system_header', and regression-test.

Now we'll notice if a header forgets to include this magic phrase.

Differential Revision: https://reviews.llvm.org/D1188

[libc++] Normalize all our '#pragma GCC system_header', and regression-test.

Now we'll notice if a header forgets to include this magic phrase.

Differential Revision: https://reviews.llvm.org/D118800

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[runtimes][NFC] Remove filenames at the top of the license notice

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 st

[runtimes][NFC] Remove filenames at the top of the license notice

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.

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[libc++] Remove support for CloudABI, which has been abandoned

Based on https://github.com/NuxiNL/cloudlibc, it appears that the CloudABI
project has been abandoned. This patch removes a bunch of Cl

[libc++] Remove support for CloudABI, which has been abandoned

Based on https://github.com/NuxiNL/cloudlibc, it appears that the CloudABI
project has been abandoned. This patch removes a bunch of CloudABI specific
logic that had been added to support that platform.

Note that some knobs like LIBCXX_ENABLE_STDIN and LIBCXX_ENABLE_STDOUT
coud be useful in their own right, however those are currently broken.
If we want to re-add such knobs in the future, we can do it like we've
done it for localization & friends so that we can officially support
that configuration.

Differential Revision: https://reviews.llvm.org/D108637

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[libc++] Use the using_if_exists attribute when provided

As discussed on cfe-dev [1], use the using_if_exists Clang attribute when
the compiler supports it. This makes it easier to port libc++ on to

[libc++] Use the using_if_exists attribute when provided

As discussed on cfe-dev [1], use the using_if_exists Clang attribute when
the compiler supports it. This makes it easier to port libc++ on top of
new platforms that don't fully support the C Standard library.

Previously, libc++ would fail to build when trying to import a missing
declaration in a <cXXXX> header. With the attribute, the declaration will
simply not be imported into namespace std, and hence it won't be available
for libc++ to use. In many cases, the declarations were *not* actually
required for libc++ to work (they were only surfaced for users to use
them as std::XXXX), so not importing them into namespace std is acceptable.

The same thing could be achieved by conscious usage of `#ifdef` along
with platform detection, however that quickly creates a maintenance
problem as libc++ is ported to new platforms. Furthermore, this problem
is exacerbated when mixed with vendor internal-only platforms, which can
lead to difficulties maintaining a downstream fork of the library.

For the time being, we only use the using_if_exists attribute when it
is supported. At some point in the future, we will start removing #ifdef
paths that are unnecessary when the attribute is supported, and folks
who need those #ifdef paths will be required to use a compiler that
supports the attribute.

[1]: http://lists.llvm.org/pipermail/cfe-dev/2020-June/066038.html

Differential Revision: https://reviews.llvm.org/D90257

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[libc++] NFC: Normalize `#endif //` comment indentation

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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Fix overload sets of strchr, strpbrk, strrchr, memchr and strstr from
<string.h> and wcschr, wcspbrk, wcsrchr, wmemchr, and wcsstr from <wchar.h> to
provide a const-correct overload set even when the

Fix overload sets of strchr, strpbrk, strrchr, memchr and strstr from
<string.h> and wcschr, wcspbrk, wcsrchr, wmemchr, and wcsstr from <wchar.h> to
provide a const-correct overload set even when the underlying C library does
not.

This change adds a new macro, _LIBCPP_PREFERRED_OVERLOAD, which (if defined)
specifies that a given overload is a better match than an otherwise equally
good function declaration without the overload. This is implemented in modern
versions of Clang via __attribute__((enable_if)), and not elsewhere.

We use this new macro to define overloads in the global namespace for these
functions that displace the overloads provided by the C library, unless we
believe the C library is already providing the correct signatures.

llvm-svn: 260337

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Revert r249929 ("Split <string.h> out of <cstring>").

This change caused problems when building code like povray that:
a) uses 'using namespace std;'
b) is built on an environment where the C librar

Revert r249929 ("Split <string.h> out of <cstring>").

This change caused problems when building code like povray that:
a) uses 'using namespace std;'
b) is built on an environment where the C library provides the "wrong"
(non-const-correct) interface for the str* functions
c) makes an unqualified call to one of those str* functions

A patch is out for review to add a facility to fix this (and to give the
correct signatures for these functions whenever possible, even when the C
library does not do so). This revert is expected to be temporary.

llvm-svn: 251665

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Split <string.h> out of <cstring>.

Also fix the overload set for the five functions whose signatures change in the
case where we can fix it. This is already covered by existing tests for the
affecte

Split <string.h> out of <cstring>.

Also fix the overload set for the five functions whose signatures change in the
case where we can fix it. This is already covered by existing tests for the
affected systems.

llvm-svn: 249929

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Make support for thread-unsafe C functions optional.

One of the aspects of CloudABI is that it aims to help you write code
that is thread-safe out of the box. This is very important if you want
to w

Make support for thread-unsafe C functions optional.

One of the aspects of CloudABI is that it aims to help you write code
that is thread-safe out of the box. This is very important if you want
to write libraries that are easy to reuse. For CloudABI we decided to
not provide the thread-unsafe functions. So far this is working out
pretty well, as thread-unsafety issues are detected really early on.

The following patch adds a knob to libc++,
_LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS, that can be set to disable
thread-unsafe functions that can easily be avoided in practice. The
following functions are not thread-safe:

- <clocale>: locale handles should be preferred over setlocale().
- <cstdlib>: mbrlen(), mbrtowc() and wcrtomb() should be preferred over
their non-restartable counterparts.
- <ctime>: asctime(), ctime(), gmtime() and localtime() are not
thread-safe. The first two are also deprecated by POSIX.

Differential Revision: http://reviews.llvm.org/D8703
Reviewed by: marshall

llvm-svn: 240527

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Revert changes inadvertantly committed

llvm-svn: 238880

Move uncaught_exeption() definition inside the #ifdef block like uncaught_exceptions()

llvm-svn: 238879

Nico Rieck: Currently _MSC_VER and _WIN32 are used to guard code which is
MSVC-specific, MSVCRT-specific, or Windows-specific. Because Clang can
also define _MSC_VER, and MSVCRT is not necessarily t

Nico Rieck: Currently _MSC_VER and _WIN32 are used to guard code which is
MSVC-specific, MSVCRT-specific, or Windows-specific. Because Clang can
also define _MSC_VER, and MSVCRT is not necessarily the only C runtime,
these macros should not be used interchangeably.

This patch divides all Windows-related bits into the aforementioned
categories. Two new macros are introduced:

- _LIBCPP_MSVC: Defined when compiling with MSVC. Detected using
_MSC_VER, excluding Clang.
- _LIBCPP_MSVCRT: Defined when using the Microsoft CRT. This is the default
when _WIN32 is defined.

This leaves _WIN32 for code using the Windows API.

This also corrects the spelling of _LIBCP_HAS_IS_BASE_OF to _LIBCPP_HAS_IS_BASE_OF.

Nico, please prepare a patch for CREDITS.TXT, thanks.

llvm-svn: 187593

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Change <cwchar> and <cstring> to look out for flags which may or may not be set by the C headers <wchar.h> and <string.h> indicating C support for the C++-altered wcschr, wcspbrk, wcsrchr, wcsstr, wm

Change <cwchar> and <cstring> to look out for flags which may or may not be set by the C headers <wchar.h> and <string.h> indicating C support for the C++-altered wcschr, wcspbrk, wcsrchr, wcsstr, wmemchr, strchr, strpbrk, strrchr, memchr, and strstr. This was already done in <cstring> for other platforms using other flags, so just had to add one more flag to the list there.

llvm-svn: 179041

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Solaris port. Currently sees around 200 test failures, mostly related to
Solaris not providing some of the locales that the test suite uses.

Note: This depends on an xlocale (partial) implementatio

Solaris port. Currently sees around 200 test failures, mostly related to
Solaris not providing some of the locales that the test suite uses.

Note: This depends on an xlocale (partial) implementation for Solaris and a
couple of fixed standard headers. These will be committed to a branch later
today.

llvm-svn: 151720

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More windows port work by Ruben Van Boxem

llvm-svn: 142732

Windows support by Ruben Van Boxem.

llvm-svn: 142235