Commit Graph

2070 Commits

Author SHA1 Message Date
Eric Fiselier
a7ae303de3 Add ABI option to remove recently inlined __shared_count functions from the library.
In order to allow inlining of previously out-of-line functions without an ABI break
libc++ provides legacy definitions in the dylib that old programs can
continue to use. Unfortunatly Windows link.exe detects this hack and diagnoses the duplicate
definitions.

This patch disable the duplicate definitions on Windows by adding an ABI option
which disables all "legacy out-of-line symbols"

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292190 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 03:16:26 +00:00
Eric Fiselier
9133eadd60 Fix DLL build by removing _LIBCPP_FUNC_VIS from member of class marked dllexport
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292185 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 03:05:31 +00:00
Kevin Hu
8993759ae9 [Test patch] Inline hot functions in libcxx shared_ptr
Moves hot functions such as atomic add into the memory header file
so that they can be inlined, which brings performance benefits.

Patch by Kevin Hu, Aditya Kumar, Sebastian Pop

Differential Revision: https://reviews.llvm.org/D24991


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292184 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-17 02:46:33 +00:00
Eric Fiselier
7d24e9101d Fix std::tuples EBO when targeting the MSVC ABI.
MSVC/clang-cl doesn't do a full EBO unless __declspec(empty_bases)
is applied to the derived type. This causes certain tuple tests
to fail.

This patch adds the empty_bases attribute to __tuple_impl in order
for tuple to fully provide the EBO.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292159 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 21:15:08 +00:00
Eric Fiselier
dae39608bb [libc++] Introduce _LIBCPP_EXTERN_VIS to fix __libcpp_debug_function link errors
Summary: On Windows tests that use `_LIBCPP_ASSERT` fail to link because the assertion handler function isn't correctly exported from the libc++ dylib. This patch fixes the dll import/export issues by introducing a new visibility macro `_LIBCPP_EXTERN_VIS` for use on external variables.

Reviewers: compnerd, smeenai, EricWF

Reviewed By: EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D28728

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292158 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 21:01:00 +00:00
Asiri Rathnayake
a1d7d2ffb8 [libcxx] Don't assume __libcpp_thread_t is an integral type
We have already refactored the underlying platform thread type into
__libcpp_thread_t, but there are few places in the source where we
still assume it is an integral type.

This patch refactores those points back into the threading API.

Differential revision: https://reviews.llvm.org/D28608

Reviewers: EricWF

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292107 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 12:19:54 +00:00
Michael Park
b894a0b46d Added a workaround for a -fdelayed-template-parsing bug.
Summary:
There seems to be an additional bug in `-fdelayed-template-parsing`
similar to
http://llvm.org/viewvc/llvm-project?view=revision&revision=236063.

This is a workaround for it for <variant> to compile with `clang-cl` on Windows.

Reviewers: EricWF

Differential Revision: https://reviews.llvm.org/D28734

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292097 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 08:14:25 +00:00
Marshall Clow
d25c997c77 Implement the missing constexpr stuff in <array>. Fixes PR#31645.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292091 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-16 03:02:10 +00:00
Eric Fiselier
543e83bfc7 Attempt two at fixing threading on Windows
Reviewers: compnerd

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D28735

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292027 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 20:19:00 +00:00
Eric Fiselier
433a39703b Fix thread creation on Windows
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292022 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 19:11:07 +00:00
Eric Fiselier
30d12e372a Fix Windows try_lock implementation
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292011 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 10:27:12 +00:00
Eric Fiselier
50ca3248fb Use __is_identifier to detect Clang extensions instead of __has_extension.
When -pedantic-errors is specified `__has_extension(<feature>)` is always
false when it would otherwise be true. This causes C++03 <atomic> to break
along with other issues.

This patch avoids the above problem by using __is_identifier(...) instead since
it is not affected by -pedantic-errors. For example instead of checking for
__has_extension(c_atomics) we now check `!__is_identifier(_Atomic)`, which
is only true when _Atomic is not a keyword provided by the compiler.

This patch applies similar changes to the detection logic for __decltype and
__nullptr as well.

Note that it does not apply this change to the C++03
`static_assert` macro since -Wc11-extensions warnings generated by expanding
that macro will appear in user code, and will not be suppressed as part of a
system header.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291995 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 04:27:58 +00:00
Eric Fiselier
bfcceeeadf Remove unused parameters in C++03
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291986 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 01:33:53 +00:00
Eric Fiselier
5ed767588b Diagnose invalid memory orderings in <atomic>
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291976 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 23:45:39 +00:00
Eric Fiselier
eaf292013d Diagnose non-const-callable hash functions and comparators
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291969 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 22:42:53 +00:00
Eric Fiselier
ebaf7dab14 Add _LIBCPP_DIAGNOSE_WARNING and _LIBCPP_DIAGNOSE_ERROR macros.
Clang recently added a `diagnose_if(cond, msg, type)` attribute
which can be used to generate diagnostics when `cond` is a constant
expression that evaluates to true. Otherwise no attribute has no
effect.

This patch adds _LIBCPP_DIAGNOSE_ERROR/WARNING macros which
use this new attribute. Additionally this patch implements
a diagnostic message when a non-const-callable comparator is
given to a container.

Note: For now the warning version of the diagnostic is useless
within libc++ since warning diagnostics are suppressed by the
system header pragma. I'm going to work on fixing this.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291961 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 22:02:08 +00:00
Eric Fiselier
ccb58d0a2c Update version to 5.0
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291928 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 18:29:56 +00:00
Eric Fiselier
1669d3dac5 Fix merge conflict caused by r291921
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291925 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 18:25:13 +00:00
Eric Fiselier
1a147b7d64 Revert "Rework fix for PR19460 - Use explicit bool as an extension instead."
This reverts commit 3a1b90a866.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291921 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-13 18:03:46 +00:00
Marshall Clow
c4d3afdfad Add new macro _LIBCPP_BUILTIN_MEMCMP_ISCONSTEXPR to use in std::char_traits.
This tells whether or not the builtin function __builtin_memcmp is constexpr.
Only defined for clang 4.0 and later, and not true for any shipping version of Apple's clang.



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291773 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-12 16:25:07 +00:00
Marshall Clow
d704617793 disable use of __builtin_memcmp temporarily to get the tests passing again
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291742 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-12 05:40:58 +00:00
Marshall Clow
ce921fa962 Implement P0426: Constexpr for std::char_traits
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291741 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-12 04:37:14 +00:00
Marshall Clow
bd7c88461b Qualify some type names that I thought were fine, but some of the bots don't like.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291580 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 18:40:01 +00:00
Marshall Clow
f6c0b90773 Fix up some mismatched SFINAE conditionsin shared_ptr; some used '_Tp*', others used 'element_type *'. Today, they're the same - but soon they won't be. No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291572 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 16:59:33 +00:00
Saleem Abdulrasool
1d3240888f threading_support: delete the critical section
Although the CriticalSection itself doesnt need to be destroyed, there
may be debug data associated with it.  Plug a possible small leak.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291536 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-10 04:18:47 +00:00
Justin Bogner
7ebce14ad5 Adorn __call_once_proxy with inline and _LIBCPP_INLINE_VISIBILITY
As per discussion with mclow and EricWF on irc, this is small and
simple enough to deserve being inlined.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291497 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-09 23:07:12 +00:00
Marshall Clow
f3e7677540 Swap two lines in __mutex_base. On systems with high clock rates, we could mistakenly return no_timeout when a mutex had timed out if we got a tick between these two lines. Thanks to Brian Cain for the bug report.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291492 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-09 22:32:11 +00:00
Dimitry Andric
8fe92cc0c9 Move _PairT declaration out of __hash_combine to avoid warning under C++98
Summary:
Some parts of the FreeBSD tree are still compiled with C++98, and until
rL288554 this has always worked fine.  After that, a complaint about the
newly introduced local _PairT is produced:

    /usr/include/c++/v1/memory:3354:27: error: template argument uses local type '_PairT' [-Werror,-Wlocal-type-template-args]
        typedef __scalar_hash<_PairT> _HashT;
                              ^~~~~~
    /usr/include/c++/v1/memory:3284:29: error: template argument uses local type '_PairT' [-Werror,-Wlocal-type-template-args]
        : public unary_function<_Tp, size_t>
                                ^~~
    /usr/include/c++/v1/memory:3356:12: note: in instantiation of template class 'std::__1::__scalar_hash<_PairT, 2>' requested here
        return _HashT()(__p);
               ^

As far as I can see, there should be no problem moving the _PairT
struct to just before the __hash_combine() function, which fixes this
particular warning.

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits, emaste

Differential Revision: https://reviews.llvm.org/D28472


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291476 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-09 20:29:35 +00:00
Marshall Clow
7d32d2f5a1 Implement P0403R1 - 'Literal suffixes for basic_string_view'. Requires clang 4.0 (specifically, r290744)
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291457 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-09 18:07:34 +00:00
Eric Fiselier
c60e8fcdcd Replace identifiers called __out because Windows.h #defines it.
Windows is greedy and it defines the identifier `__out` as a macro.
This patch renames all conflicting libc++ identifiers in order
to correctly work on Windows.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291345 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 11:27:06 +00:00
Saleem Abdulrasool
678eadd13f provide Win32 native threading
Add an implementation for the Win32 threading model as a backing API for
the internal c++ threading interfaces.  This uses the Fls* family for
the TLS (which has the support for adding termination callbacks),
CRITICAL_SECTIONs for the recursive mutex, and Slim Reader/Writer locks
(SRW locks) for non-recursive mutexes.  These APIs should all be
available on Vista or newer.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291333 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 03:07:45 +00:00
Eric Fiselier
32b19c3d9f [libc++] Tolerate presence of __deallocate macro
Summary:
On Windows the identifier `__deallocate` is defined as a macro by one of the Windows system headers. Previously libc++ worked around this by `#undef __deallocate` and generating a warning. However this causes the WIN32 version of `__threading_support` to always generate a warning on Windows. This is not OK.

This patch renames all usages of `__deallocate` internally as to not conflict with the macro.

Reviewers: mclow.lists, majnemer, rnk, rsmith, smeenai, compnerd

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D28426

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291332 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 03:01:24 +00:00
Eric Fiselier
32ff3279eb Add _LIBCPP_ABI_[ITANIUM|MICROSOFT] macros.
This patch adds a libc++ configuration macro for the ABI we
are targeting, either Itanium or Microsoft. For now we configure
for the Microsoft ABI when on Windows with a compiler that defines
_MSC_VER. However this is only temporary until Clang implements
builtin macros we can use.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291329 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 02:43:58 +00:00
Eric Fiselier
1572c468b3 Fix breakage caused when _LIBCPP_HAS_THREAD_API_PTHREAD is manually defined
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291298 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-06 23:15:16 +00:00
Eric Fiselier
5170d7d88f Add _LIBCPP_COMPILER_[CLANG|GCC|MSVC|IBM] macros.
This patch refactors the compiler detection done in `__config` by creating a
set of `_LIBCPP_COMPILER_<TYPE>` macros. The goal of this patch is to make
it easier to detect what compiler is being used outside of `__config`.

Additionally this patch removes workarounds for GCC in `__bit_reference`. I
tested GCC 4.8 and 4.9 without the workaround and neither seemed to need it
anymore.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291286 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-06 21:42:58 +00:00
Eric Fiselier
8eb066a106 Replace _LIBCPP_HAS_NO_DELETED_FUNCTIONS with _LIBCPP_CXX03_LANG
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291278 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-06 20:58:25 +00:00
Eric Fiselier
66134e8a5f [libc++] Cleanup and document <__threading_support>
Summary:
This patch attempts to clean up the macro configuration mess in `<__threading_support>`, specifically the mess involving external threading variants. Additionally this patch adds design documentation for `<__threading_support>` and the configuration macros it uses.

The primary change in this patch is separating the idea of an "external API" provided by `<__external_threading>` and the idea of having an external threading library. Now `_LIBCPP_HAS_THREAD_API_EXTERNAL` means that libc++ should use `<__external_threading>` and that the header is expected to exist.  Additionally the new macro `_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL` is now used to configure for using an "external library"  with the default threading API.

Reviewers: compnerd, rmaprath

Subscribers: smeenai, cfe-commits, mgorny

Differential Revision: https://reviews.llvm.org/D28316

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291275 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-06 20:05:40 +00:00
Saleem Abdulrasool
aa6429dc41 typeinfo: style adjustments for adding MS ABI RTTI
This is motivated by adding a third RTTI scheme to libc++.  Split out
the two forms of the itanium RTTI representation.  This is based on
suggestions from Eric Fiselier.  NFC

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291174 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 21:22:22 +00:00
Saleem Abdulrasool
3451a65e1b thread_support: split out {,non-}recursive mutex
Split out the recursive and non-recursive mutex.  This split is needed
for platforms which may use differing types for the two mutex (e.g.
Win32 threads).

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291145 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 17:54:45 +00:00
Eric Fiselier
856712bda2 [libcxx] Fix PR31402: map::__find_equal_key has undefined behavior.
Summary:
This patch fixes llvm.org/PR31402 by replacing `map::__find_equal_key` with `__tree::__find_equal`, which has already addressed the same undefined behavior.

Unfortunately I haven't been able to write a test case which causes the UBSAN diagnostic mentioned in the bug report. I can write tests which exercise the UB but for some reason they do not cause UBSAN to fail. Any help writing a test case would be appreciated.


Reviewers: mclow.lists, vsk, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D28131

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291087 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 06:06:18 +00:00
Eric Fiselier
c3dfeced41 Fix PR26961 - Add default constructor to std::pointer_safety struct.
In ABI v1 libc++ implements std::pointer_safety as a class type instead
of an enumeration. However this class type does not provide
a default constructor as it should. This patch adds that default constructor.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291059 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 01:28:40 +00:00
Eric Fiselier
46a0c2ef0c Fix std::pointer_safety type in ABI v2
In the C++ standard `std::pointer_safety` is defined
as a C++11 strongly typed enum. However libc++ currently defines
it as a class type which simulates a C++11 enumeration. This
can be detected in valid C++ code.

This patch introduces an the _LIBCPP_ABI_POINTER_SAFETY_ENUM_TYPE ABI option.
When defined `std::pointer_safety` is implemented as an enum type.
Unfortunatly this also means it can no longer be provided as an extension
in C++03.

Additionally this patch moves the definition for `get_pointer_safety()`
out of the dylib, and into the headers. New usages of `get_pointer_safety()`
will now use the inline version instead of the dylib version. However in
order to keep the dylib ABI compatible the old definition is explicitly
compiled into it.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291046 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-05 01:15:42 +00:00
Eric Fiselier
c3589a8305 [NFC] Rename _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS
The name _LIBCPP_TYPE_VIS_ONLY is no longer accurate because both
_LIBCPP_TYPE_VIS and _LIBCPP_TYPE_VIS_ONLY expand to
__attribute__((__type_visibility__)) with Clang. The only remaining difference
is that _LIBCPP_TYPE_VIS_ONLY can be applied to templates whereas
_LIBCPP_TYPE_VIS cannot (due to dllimport/dllexport not being allowed on
templates).

This patch renames _LIBCPP_TYPE_VIS_ONLY to _LIBCPP_TEMPLATE_VIS.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291035 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 23:56:00 +00:00
Eric Fiselier
2d2247d0da Fix private inheritance in C++03 tuple_size
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291032 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 23:35:51 +00:00
Marshall Clow
3df90c94a3 Implement P0505: 'Wording for GB 50'
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291028 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 23:03:24 +00:00
Eric Fiselier
06a0febbbd [libcxx] Re-implement LWG 2770 again: Fix tuple_size to work with structured bindings
Summary:
This patch attempts to re-implement a fix for LWG 2770, but not the actual specified PR. 

The PR for 2770 specifies tuple_size<T const> as only conditionally providing a `::value` member. However C++17 structured bindings require `tuple_size<T const>` to be complete only if  `tuple_size<T>` is also complete. Therefore this patch implements only provides the specialization `tuple_size<T CV>` iff `tuple_size<T>` is a complete type.

This fixes http://llvm.org/PR31513.

Reviewers: mclow.lists, rsmith, mpark

Subscribers: mpark, cfe-commits

Differential Revision: https://reviews.llvm.org/D28222

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291019 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 22:38:46 +00:00
Marshall Clow
e22af6b758 Implement the last bit of P0031: 'A Proposal to Add Constexpr Modifiers to reverse_iterator, move_iterator, array and Range Access' for C++17
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290976 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 17:58:17 +00:00
Saleem Abdulrasool
4508216a70 config: MSVC 19+ has unicode chars
MSVC 19+ and clang-cl with emulation version >= 19.00 will provide
char{16,32}_t as builtin types.  Adjust the configuration accordingly.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290940 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 05:49:59 +00:00
Saleem Abdulrasool
5c737d8395 Refactor bitscan64 check
Introduce a `_LIBCPP_HAS_BITSCAN64` macro to specify if the 64-bit
variant of the bitscan family of APIs is available.  This avoids
duplicating the check in the support header.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290924 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-04 01:53:24 +00:00
Saleem Abdulrasool
e34f9d5ef3 clean up use of _WIN32
Replace the use of _WIN32 in libc++. Replace most use with a C runtime
check _LIBCPP_MSVCRT or the new _LIBCPP_WIN32 to indicate that we are
using the Win32 API. Use a new _LIBCPP_WCHAR_IS_UCS2 to indicate that we
are on an environment that has a short wchar_t.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290910 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-03 21:53:51 +00:00