Commit Graph

89 Commits

Author SHA1 Message Date
Mark de Wever 24e1736d84 [libc++][random] Removes transitive includes.
It seems these includes are still provided by the sub headers, so it only
removes the duplicates.

There is no change in the list of includes, but the change affects the
modular build. By not having the includes in the top-level header the
module map has changed. This uncovers missing includes in the tests
and missing exports in the module map. This causes the huge amount of
changes in the patch.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D133252
2022-09-11 17:39:27 +02:00
Igor Zhukov db0ac307c9 [libc++] Fix warning C4244 in std/numerics/rand/rand.dist/rand.dist.samp/rand.dist.samp.discrete/eval.pass.cpp
frederick-vs-ja noticed that https://github.com/microsoft/STL/pull/2976#issuecomment-1201926893
while we are working on updating LLVM submodule for MS STL:

    [...]\std\numerics\rand\rand.dist\rand.dist.samp\rand.dist.samp.discrete\eval.pass.cpp(33): error C2220: the following warning is treated as an error
    [...]\std\numerics\rand\rand.dist\rand.dist.samp\rand.dist.samp.discrete\eval.pass.cpp(287): note: see reference to function template instantiation 'void tests<__int64>(void)' being compiled
    [...]\std\numerics\rand\rand.dist\rand.dist.samp\rand.dist.samp.discrete\eval.pass.cpp(33): warning C4244: 'argument': conversion from '__int64' to 'const unsigned int', possible loss of data

Differential Revision: https://reviews.llvm.org/D130963
2022-08-02 20:44:46 -04:00
Muhammad Usman Shahid 76476efd68 Rewording "static_assert" diagnostics
This patch rewords the static assert diagnostic output. Failing a
_Static_assert in C should not report that static_assert failed. This
changes the wording to be more like GCC and uses "static assertion"
when possible instead of hard coding the name. This also changes some
instances of 'static_assert' to instead be based on the token in the
source code.

Differential Revision: https://reviews.llvm.org/D129048
2022-07-25 07:22:54 -04:00
Louis Dionne 07e984bc52 [libc++] Support int8_t and uint8_t in integer distributions as an extension
In D125283, we ensured that integer distributions would not compile when
used with arbitrary unsupported types. This effectively enforced what
the Standard mentions here: http://eel.is/c++draft/rand#req.genl-1.5.

However, this also had the effect of breaking some users that were
using integer distributions with unsupported types like int8_t. Since we
already support using __int128_t in those distributions, it is reasonable
to also support smaller types like int8_t and its unsigned variant. This
commit implements that, adds tests and documents the extension. Note that
we voluntarily don't add support for instantiating these distributions
with bool and char, since those are not integer types. However, it is
trivial to replace uses of these random distributions on char using int8_t.

It is also interesting to note that in the process of adding tests
for smaller types, I discovered that our distributions sometimes don't
provide as faithful a distribution when instantiated with smaller types,
so I had to relax a couple of tests. In particular, we do a really bad
job at implementing the negative binomial, geometric and poisson distributions
for small types. I think this all boils down to the algorithm we use in
std::poisson_distribution, however I am running out of time to investigate
that and changing the algorithm would be an ABI break (which might be
reasonable).

As part of this patch, I also added a mitigation for a very likely
integer overflow bug we were hitting in our tests in negative_binomial_distribution.
I also filed http://llvm.org/PR56656 to track fixing the problematic
distributions with int8_t and uint8_t.

Supersedes D125283.

Differential Revision: https://reviews.llvm.org/D126823
2022-07-22 08:33:01 -04:00
Erich Keane 1da3119025 Revert "Rewording the "static_assert" to static assertion"
Looks like we again are going to have problems with libcxx tests that
are overly specific in their dependency on clang's diagnostics.

This reverts commit 6542cb55a3.
2022-07-21 06:40:14 -07:00
Muhammad Usman Shahid 6542cb55a3 Rewording the "static_assert" to static assertion
This patch is basically the rewording of the static assert statement's
output(error) on screen after failing. Failing a _Static_assert in C
should not report that static_assert failed. It’d probably be better to
reword the diagnostic to be more like GCC and say “static assertion”
failed in both C and C++.

consider a c file having code

_Static_assert(0, "oh no!");

In clang the output is like:

<source>:1:1: error: static_assert failed: oh no!
_Static_assert(0, "oh no!");
^              ~
1 error generated.
Compiler returned: 1

Thus here the "static_assert" is not much good, it will be better to
reword it to the "static assertion failed" to more generic. as the gcc
prints as:

<source>:1:1: error: static assertion failed: "oh no!"
    1 | _Static_assert(0, "oh no!");
          | ^~~~~~~~~~~~~~
          Compiler returned: 1

The above can also be seen here. This patch is about rewording
the static_assert to static assertion.

Differential Revision: https://reviews.llvm.org/D129048
2022-07-21 06:34:14 -07:00
Corentin Jabot da1609ad73 Improve the formatting of static_assert messages
Display 'static_assert failed: message' instead of
'static_assert failed "message"' to be consistent
with other implementations and be slightly more
readable.

Reviewed By: #libc, aaron.ballman, philnik, Mordante

Differential Revision: https://reviews.llvm.org/D128844
2022-06-30 23:59:21 +02:00
Louis Dionne a7f9895cc1 [runtimes] Rename various libcpp-has-no-XYZ Lit features to just no-XYZ
Since those features are general properties of the environment, it makes
sense to use them from libc++abi too, and so the name libcpp-has-no-xxx
doesn't make sense.

Differential Revision: https://reviews.llvm.org/D126482
2022-05-27 15:24:45 -04:00
Nikolas Klauser eb1c50378e [libc++][NFC] Rename rand.dis to rand.dist
Reviewed By: ldionne, #libc

Spies: libcxx-commits, mgrang, mstorsjo

Differential Revision: https://reviews.llvm.org/D126221
2022-05-27 21:22:20 +02:00
Louis Dionne b7042b73a3 [libc++] Add back-deployment testing on arm64 macs
Differential Revision: https://reviews.llvm.org/D123081
2022-04-07 10:15:40 -04:00
Nikolas Klauser 14324fa428 [libc++] Add warning pragma macros in the test suite
Reviewed By: ldionne, #libc, EricWF

Spies: EricWF, libcxx-commits

Differential Revision: https://reviews.llvm.org/D121552
2022-03-17 00:11:20 +01:00
Joe Loser d2baefae68
[libc++] Replace _LIBCPP_HAS_NO_CONCEPTS with _LIBCPP_STD_VER > 17. NFCI.
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
2022-03-13 12:32:06 -04:00
Mark de Wever 8f972cb0fd [libc++][nfc] Add TEST_HAS_NO_INT128.
Avoid using the libc++ internal `_LIBCPP_HAS_NO_INT128` in our tests.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D117992
2022-01-27 17:31:27 +01:00
Mark de Wever 5d3ab6a2bb [libc++][nfc] Include test_macros.h in more tests.
This should fix the regressions detected in D117992.

This lands before D117992 to avoid breaking main.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D118056
2022-01-27 17:28:26 +01:00
Martin Storsjö 0d5b35934e [libcxx] [test] Narrow down a MinGW bug workaround in rand.dist.uni.int/eval.pass.cpp
Differential Revision: https://reviews.llvm.org/D118235
2022-01-27 13:19:06 +02:00
Arthur O'Dwyer 8b29b84c99 [libc++] Fix LWG3422 "Issues of seed_seq's constructors"
https://cplusplus.github.io/LWG/issue3422

Also add a static_assert to check the "Mandates:" on the
iterator-pair constructor. Oddly, the `InputIterator` parameter
itself is merely preconditioned, not constrained, to satisfy the
input iterator requirements.

Also drive-by rename `init` to `__init`.

Differential Revision: https://reviews.llvm.org/D117962
2022-01-24 20:14:25 -05:00
Casey Carter 4e00a1921f [libcxx][test] compiler options are non-portable
... it's easier to suppress warnings internally, where we can detect the compiler.

* Rename `TEST_COMPILER_C1XX` to `TEST_COMPILER_MSVC`
* Rename all `TEST_WORKAROUND_C1XX_<meow>` to `TEST_WORKAROUND_MSVC_<meow>`

Differential Revision: https://reviews.llvm.org/D117422
2022-01-18 11:34:57 -08:00
Arthur O'Dwyer 5820322cb1 [libc++] [test] UNSUPPORTED my new uniform_int_distribution test on MinGW.
After 9fe67486cc, this test fails on MinGW for some reason.
https://buildkite.com/llvm-project/libcxx-ci/builds/7922#9e267294-441d-4b79-8a19-30fdb5599c1f
All it says in the build output is

    note: command had no output on stdout or stderr
    error: command failed with exit status: 4294967295
2022-01-17 16:32:44 -05:00
Arthur O'Dwyer 9fe67486cc [libc++] [test] Improve the test for `uniform_int_distribution<T>`.
Extracted from https://reviews.llvm.org/D114920
2022-01-17 10:31:10 -05:00
Arthur O'Dwyer 0359b85c61 [libc++] [ABI BREAK] Conform lognormal_distribution::param_type.
Fixes #52906.

Differential Revision: https://reviews.llvm.org/D116344
2022-01-17 10:22:41 -05:00
Louis Dionne d202c76441 [libc++] Start using `arc4random()` to implement `std::random_device` on Apple
On Apple platforms, arc4random is faster than /dev/urandom, and it is
the recommended user-space RNG according to Apple's own OS folks.

This commit adds an ABI switch to guard ABI-break-protections in
std::random_device, and starts using arc4random instead of /dev/urandom
to implement std::random_device on Apple platforms.

Note that previously, `std::random_device` would allow passing a custom
token to its constructor, and that token would be interpreted as the name
of a file to read entropy from. This was implementation-defined and
undocumented. After this change, Apple platforms will be using arc4random()
instead, and any custom token passed to the constructor will be ignored.
This behavioral change will also impact other platforms that use the
arc4random() implementation, such as OpenBSD. This should be fine since
that is effectively a relaxation of the constructor's requirements.

rdar://86638350

Differential Revision: https://reviews.llvm.org/D116045
2022-01-12 11:24:23 -05:00
Louis Dionne 84654f2733 [libc++] Refactor the tests for std::random_device
That will make it easier to change the behavior of the arc4random()
based implementation. Note that in particular, the eval.pass.cpp test
used to work with non "/dev/random" based implementations because we'd
throw an exception upon constructing the random_device. This patch makes
the intent of the test clearer.
2022-01-10 16:34:16 -05:00
Louis Dionne d5b3cb0711 [libc++][NFC] Fix links to https://llvm.org/PR20183 in the tests 2021-12-21 10:34:08 -05:00
Fabian Wolff b254c2e2c4 [libc++] Fix `uniform_int_distribution` for 128-bit result type
Fixes https://llvm.org/PR51520. The problem is that `uniform_int_distribution`
currently uses an unsigned integer with at most 64 bits internally, which
is then casted to the desired result type. If the result type is `int64_t`,
this will produce a negative number if the most significant bit is set,
but if the result type is `__int128_t`, the value remains non-negative
and will be out of bounds for the example in PR#51520. (The reason why
it also seems to work if the upper or lower bound is changed is
because the branch at [1] will then no longer be taken, and proper
rejection sampling takes place.)

The bigger issue here is probably that `uniform_int_distribution` can be
instantiated with `__int128_t` but will silently produce incorrect results
(only the lowest 64 bits can ever be set). libstdc++ also supports `__int128_t`
as a result type, so I have simply extended the maximum width of the
internal intermediate result type.

[1]: https://github.com/llvm/llvm-project/blob/6d28dffb6/libcxx/include/__random/uniform_int_distribution.h#L266-L267

Differential Revision: https://reviews.llvm.org/D114129
2021-12-01 11:03:29 -05:00
Arthur O'Dwyer 344cef6695 [libc++] Granularize the <random> header. NFCI.
Actually there's one functional change here, which is that users can
no longer depend on <random> to include all of C++20 <concepts>. That
inclusion is so new that we believe nobody should be depending on it
yet, even in the presence of Hyrum's Law. We keep the includes of <vector>,
<algorithm>, etc., so as not to break pre-C++20 Hyrum's Law users.

Differential Revision: https://reviews.llvm.org/D114281
2021-11-22 13:24:27 -05:00
Louis Dionne c360553c15 [runtimes] Simplify how we specify XFAIL & friends based on the triple
Now that Lit supports regular expressions inside XFAIL & friends, it is
much easier to write Lit annotations based on the triple.

Differential Revision: https://reviews.llvm.org/D104747
2021-07-01 14:03:30 -04:00
Louis Dionne 2cf78d4ead [libc++] Remove unused variable warnings
Since D100581, Clang started flagging this variable which is set but
never read. Based on comparing this function with __match_at_start_posix_nosubs
(which is very similar), I am pretty confident that `__j` was simply left
behind as an oversight in Howard's 6afe8b0a23.

Also workaround some unused variable warnings in the <random> tests.
It's pretty lame that we're not asserting the skew and kurtosis of
the binomial and negative binomial distributions, but that should be
tackled separately.

Differential Revision: https://reviews.llvm.org/D103533
2021-06-03 09:43:08 -04:00
Arthur O'Dwyer 866b27950a [libc++] s/_VSTD::is_unsigned/is_unsigned/ in <random>. NFCI. 2021-05-11 12:23:55 -04:00
Louis Dionne 74d096e558 [libc++] Move handling of the target triple to the DSL
This fixes a long standing issue where the triple is not always set
consistently in all configurations. This change also moves the
back-deployment Lit features to using the proper target triple
instead of using something ad-hoc.

This will be necessary for using from scratch Lit configuration files
in both normal testing and back-deployment testing.

Differential Revision: https://reviews.llvm.org/D102012
2021-05-08 11:10:53 -04:00
Marek Kurdej 5c703f0fd8 [libc++] Build and test with -Wundef warning. NFC.
This will avoid typos like `_LIBCPP_STD_VERS` (<future>) or using `#if TEST_STD_VER > 17` without including "test_macros.h".

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D99515
2021-04-01 08:32:56 +02:00
Christopher Di Bella 9f4f6ac94b [libcxx] adds concept `std::uniform_random_bit_generator`
Implements parts of:
    - P0898R3 Standard Library Concepts
    - P1754 Rename concepts to standard_case for C++20, while we still can

Differential Revision: https://reviews.llvm.org/D96577
2021-02-19 01:47:29 +00:00
Marek Kurdej f3b979b65e [libc++] Use ioctl when available to get random_device entropy.
Implemented the idea from D94571 to improve entropy on Linux.

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D94953
2021-01-21 18:01:02 +01:00
Marek Kurdej a11f8b1ad6 [libc++] [P0935] [C++20] Eradicating unnecessarily explicit default constructors from the standard library.
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0935r0.html

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D91292
2021-01-19 08:22:06 +01:00
Richard Smith 7de9c61f31 Fix test expectation to cope with custom version namespaces. 2020-12-13 22:43:24 -08:00
zoecarver 31dfaff3b3 [libc++] Change requirements on linear_congruential_engine.
This patch changes how linear_congruential_engine picks its randomization
algorithm. It adds two restrictions, `_OverflowOK` and `_SchrageOK`.
`_OverflowOK` means that m is a power of two so using the classic
`(a * x + c) % m` will create a meaningless overflow. The second checks
that Schrage's algorithm will produce results that are in bounds of min
and max. This patch fixes https://llvm.org/PR27839.

Differential Revision: D65041
2020-11-10 18:23:22 -08:00
Louis Dionne 5a829ef6ad [libc++] Fix invalid parsing of ints in a <random> test
The strings were concatenated together without adding spaces between
numbers, which lead to numbers that wouldn't fit in an unsigned int.

Thanks to Casey Carter for the find.
2020-11-02 19:20:59 -05:00
Louis Dionne 88ffc72717 [libc++] Add a libc++ configuration that does not support localization
When porting libc++ to embedded systems, it can be useful to drop support
for localization, which these systems don't implement or care about.

Differential Revision: https://reviews.llvm.org/D90072
2020-10-27 14:56:30 -04:00
Louis Dionne d1afe2e25c [libc++] Remove the reliance of several <random> tests on <iostream> 2020-10-26 18:02:01 -04:00
Louis Dionne e0d01294bc [libc++] Allow building libc++ on platforms without a random device
Some platforms, like several embedded platforms, do not provide a source
of randomness through a random device. This commit makes it possible to
build and test libc++ for such platforms, i.e. without std::random_device.

Surprisingly, the only functionality that doesn't work on such platforms
is std::random_device itself -- everything else in <random> still works,
one just has to find alternative ways to seed the PRNGs.
2020-10-15 12:20:29 -04:00
Louis Dionne 31cbe0f240 [libc++] Remove the c++98 Lit feature from the test suite
C++98 and C++03 are effectively aliases as far as Clang is concerned.
As such, allowing both std=c++98 and std=c++03 as Lit parameters is
just slightly confusing, but provides no value. It's similar to allowing
both std=c++17 and std=c++1z, which we don't do.

This was discovered because we had an internal bot that ran the test
suite under both c++98 AND c++03 -- one of which is redundant.

Differential Revision: https://reviews.llvm.org/D80926
2020-06-03 09:37:22 -04:00
Louis Dionne 7a6aaf9b23 [libc++] Remove workaround for .fail.cpp tests that don't have clang-verify markup
By renaming .fail.cpp tests that don't need clang-verify to .compile.fail.cpp,
the new test format will not try to compile these tests with clang-verify,
and the old test format will work just the same. However, this allows
removing a workaround that requires parsing each test looking for
clang-verify markup.

After this change, a .fail.cpp test should always have clang-verify markup.
When clang-verify is not supported by the compiler, we will just check that
these tests fail to compile. When clang-verify is supported, these tests
will be compiled with clang-verify whether they have markup or not (so
they should have markup, or they will fail).

This simplifies the test suite and also ensures that all of our .fail.cpp
tests provide clang-verify markup. If it's impossible for a test to have
clang-verify markup, it can be moved to a .compile.fail.cpp test, which
are unconditionally just checked for compilation failure.
2020-04-15 10:53:37 -04:00
Louis Dionne 7149bb7068 [libc++] NFC: Clean up a lot of old Lit features
The libc++ test suite has a lot of old Lit features used to XFAIL tests
and mark them as UNSUPPORTED. Many of them are to workaround problems on
old compilers or old platforms. As time goes by, it is good to go and
clean those up to simplify the configuration of the test suite, and also
to reflect the testing reality. It's not useful to have markup that gives
the impression that e.g. clang-3.3 is supported, when we don't really
test on it anymore (and hence several new tests probably don't have the
necessary markup on them).
2020-04-10 17:20:29 -04:00
Louis Dionne aaaa25e23d [libc++] Remove useless nothing_to_do.pass.cpp tests
The testing script used to test libc++ historically did not like directories
without any testing files, so these tests had been added. Since this is
not necessary anymore, we can now remove these files. This has the benefit
that the total number of tests reflects the real number of tests more
closely, and we also skip some unnecessary work (especially relevant when
running tests over SSH).

However, some nothing_to_do.pass.cpp tests actually serve the purpose of
documenting that an area of the Standard doesn't need to be tested, or is
tested elsewhere. These files are not removed by this commit.

Removal done with:

  import os
  import itertools
  for (dirpath, dirnames, filenames) in itertools.chain(os.walk('./libcxx/test'),
                                                        os.walk('./libcxxabi/test')):
      if len(filenames + dirnames) > 1 and \
         any(p == 'nothing_to_do.pass.cpp' for p in filenames):
          os.remove(os.path.join(dirpath, 'nothing_to_do.pass.cpp'))
2020-04-03 13:48:34 -04:00
Atmn Patel 51b78a3e06 [libc++] Bugfix to std::binomial_distribution<int>
The current implementation of binomial_distribution is not guaranteed to
converge for certain extreme configurations of the engine and distribution.
This is due to a mistake in the implementation of the algorithm from the
given reference paper. The algorithm in the paper is guaranteed to
terminate but has redundant statements. The current implementation
simplified away the redundancy into a while loop, but it excludes the
return condition of the case where a good sample cannot be returned for
the particular sample being used from the uniform distribution, which is
what causes the infinite loop. This change guarantees termination by
recognizing that a good sample cannot be returned and returning 0 after
breaking the loop. This is also in contrast to the paper because the
return value as specified in the paper violates basic checks in at least
a subset of the extreme cases where the current implementation fails to
terminate. This default return value of 0 is satisfactory for the
extreme case known so far.

Since this is only meant to affect extreme cases where the algorithm
does not terminate anyways, the behavior is expected to remain exactly
the same for all non-extreme cases that have been terminating so far.

Fixes https://llvm.org/PR44847

Differential Revision: https://reviews.llvm.org/D74997
2020-03-17 15:56:16 -04:00
Louis Dionne 0ec6a4882e [libc++] Fix potential OOB in poisson_distribution
See details in the original Chromium bug report:
    https://bugs.chromium.org/p/chromium/issues/detail?id=994957
2019-11-07 13:29:40 +00:00
Louis Dionne b43923da5b [libc++] Fix broken <random> test
In r369429, I hoisted a floating point computation to a variable in order
to remove a warning. However, it turns out this doesn't play well with
floating point arithmetic. This commit reverts r369429 and instead casts
the result of the floating point computation to remove the warning.

Whether hoisting the computaiton to a variable should give the same
result can be investigated independently.

llvm-svn: 369693
2019-08-22 19:35:46 +00:00
Louis Dionne c310e5a7ab [libc++] Avoid implicit conversion warning in a <random> test
By stashing the computation of `E::max() - E::min()` in a variable, we
avoid the warning introduced in r367497. Note that we use `auto` to
avoid having to deduce the type of the computation, which is not a
problem since Clang provides `auto` as an extension even in C++03 (and
we disable warnings related to using C++11 extensions in the test suite).

llvm-svn: 369429
2019-08-20 19:28:26 +00:00
Marshall Clow 7fc6a55688 Add include for 'test_macros.h' to all the tests that were missing them. Thanks to Zoe for the (big, but simple) patch. NFC intended.
llvm-svn: 362252
2019-05-31 18:35:30 +00:00
Louis Dionne afeff20c0f [libc++] Remove unnecessary <iostream> #includes in tests
Some tests #include <iostream> but they don't use anything from the
header. Those are probably artifacts of when the tests were developped.

llvm-svn: 357181
2019-03-28 16:38:15 +00:00
JF Bastien 2df59c5068 Support tests in freestanding
Summary:
Freestanding is *weird*. The standard allows it to differ in a bunch of odd
manners from regular C++, and the committee would like to improve that
situation. I'd like to make libc++ behave better with what freestanding should
be, so that it can be a tool we use in improving the standard. To do that we
need to try stuff out, both with "freestanding the language mode" and
"freestanding the library subset".

Let's start with the super basic: run the libc++ tests in freestanding, using
clang as the compiler, and see what works. The easiest hack to do this:

In utils/libcxx/test/config.py add:

  self.cxx.compile_flags += ['-ffreestanding']

Run the tests and they all fail.

Why? Because in freestanding `main` isn't special. This "not special" property
has two effects: main doesn't get mangled, and main isn't allowed to omit its
`return` statement. The first means main gets mangled and the linker can't
create a valid executable for us to test. The second means we spew out warnings
(ew) and the compiler doesn't insert the `return` we omitted, and main just
falls of the end and does whatever undefined behavior (if you're luck, ud2
leading to non-zero return code).

Let's start my work with the basics. This patch changes all libc++ tests to
declare `main` as `int main(int, char**` so it mangles consistently (enabling us
to declare another `extern "C"` main for freestanding which calls the mangled
one), and adds `return 0;` to all places where it was missing. This touches 6124
files, and I apologize.

The former was done with The Magic Of Sed.

The later was done with a (not quite correct but decent) clang tool:

  https://gist.github.com/jfbastien/793819ff360baa845483dde81170feed

This works for most tests, though I did have to adjust a few places when e.g.
the test runs with `-x c`, macros are used for main (such as for the filesystem
tests), etc.

Once this is in we can create a freestanding bot which will prevent further
regressions. After that, we can start the real work of supporting C++
freestanding fairly well in libc++.

<rdar://problem/47754795>

Reviewers: ldionne, mclow.lists, EricWF

Subscribers: christof, jkorous, dexonsmith, arphaman, miyuki, libcxx-commits

Differential Revision: https://reviews.llvm.org/D57624

llvm-svn: 353086
2019-02-04 20:31:13 +00:00