Commit Graph

74 Commits

Author SHA1 Message Date
Martin Storsjö 7db4f2c694 [libcxx] [Windows] Store the lconv struct returned from localeconv in locale_t
This fixes using non-default locales, which currently can crash when
e.g. formatting numbers.

Within the localeconv_l function, the per-thread locale is temporarily
changed with __libcpp_locale_guard, then localeconv() is called,
returning an lconv * struct pointer.

When localeconv_l returns, the __libcpp_locale_guard dtor restores
the per-thread locale back to the original. This invalidates the
contents of the earlier returned lconv struct, and all C strings
that are pointed to within it are also invalidated.

Thus, to have an actually working localeconv_l function, the
function needs to allocate some sort of storage for the returned
contents, that stays valid for as long as the caller needs to use
the returned struct.

Extend the libcxx/win32 specific locale_t class with storage for
a deep copy of a lconv struct, and change localeconv_l to take
a reference to the locale_t, to allow it to store the returned
lconv struct there.

This works fine for libcxx itself, but wouldn't necessarily be right
for a caller that uses libcxx's localeconv_l function.

This fixes around 11 of libcxx's currently failing tests on windows.

Differential Revision: https://reviews.llvm.org/D69505
2020-01-29 22:37:11 +02:00
Martin Storsjö 337e435964 [libcxx] [Windows] Make a more proper implementation of strftime_l for mingw with msvcrt.dll
This also makes this function consistent with the rest of the
libc++ provided fallbacks.

The locale support in msvcrt.dll is very limited anyway; it can
only be configured processwide, not per thread, and it only seems
to support the locales "C" and "" (the user set locale), so it's
hard to make any meaningful automatic test for it. But manually tested,
this change does make time formatting locale code in libc++ output
times in the user requested format, when using locale "".

Differential Revision: https://reviews.llvm.org/D69554
2020-01-14 22:29:47 +02:00
Shoaib Meenai d018b556c7 [libcxx] Omit unneeded locale fallbacks on Android 21+
Android API level 21 and above have all these functions available, so we
don't need to include our fallback definitions.

Differential Revision: https://reviews.llvm.org/D69983
2019-11-25 11:06:08 -08:00
Louis Dionne 6b77ebdc91 [NFC] Strip trailing whitespace from libc++ 2019-10-23 11:19:19 -07:00
Louis Dionne 3836a49039 [libc++] Remove empty header xlocale/xlocale.h
Summary:
I can't think of a reason for shipping this empty header. If there is
a reason to do so, then hopefully this review can uncover it.

Reviewers: mclow.lists, EricWF

Subscribers: mgorny, christof, jkorous, dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D59137

llvm-svn: 355829
2019-03-11 15:41:51 +00:00
Chandler Carruth 57b08b0944 Update more file headers across all of the LLVM projects in the monorepo
to reflect the new license. These used slightly different spellings that
defeated my regular expressions.

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: 351648
2019-01-19 10:56:40 +00:00
Eric Fiselier a0e23576b8 Fix Shadowing warning on Windows
llvm-svn: 343439
2018-10-01 02:54:08 +00:00
Jordan Rupprecht 78b6374997 [libc++] Exclude posix_l/strtonum fallback inclusion for newlib > 2.4
Summary:
[libc++] Exclude posix_l/strtonum fallback inclusion for newlib > 2.4

r338122 changed the linkage of some methods which revealed an existing ODR violation, e.g.:
projects/libcxx/include/support/xlocale/__posix_l_fallback.h:83:38: error: 'internal_linkage' attribute does not appear on the first declaration of 'iswcntrl_l'
inline _LIBCPP_INLINE_VISIBILITY int iswcntrl_l(wint_t c, locale_t) {
                                     ^
lib/include/wctype.h:55:12: note: previous definition is here
extern int      iswcntrl_l (wint_t, locale_t);

These were added to newlib in 2.4 [1] [2], so move them to the already existing include guard.

[1] https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=commit;h=238455adfab4f8070ac65400aac22bb8a9e502fc
[2] https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;a=commit;h=8493c1631643fada62384768408852bc0fa6ff44

Reviewers: ldionne, rsmith, EricWF

Subscribers: christof, cfe-commits

Differential Revision: https://reviews.llvm.org/D49927

llvm-svn: 338157
2018-07-27 20:02:58 +00:00
Louis Dionne dc7200b486 [libc++] Take 2: Replace uses of _LIBCPP_ALWAYS_INLINE by _LIBCPP_INLINE_VISIBILITY
Summary:
We never actually mean to always inline a function -- all the uses of
the macro I could find are actually attempts to control the visibility
of symbols. This is better described by _LIBCPP_INLINE_VISIBILITY, which
is actually always defined the same.

This change is orthogonal to the decision of what we're actually going
to do with _LIBCPP_INLINE_VISIBILITY -- it just simplifies things by
having one canonical way of doing things.

Note that this commit had originally been applied in r336369 and then
reverted in r336382 because of unforeseen problems. Both of these problems
have now been fixed.

Reviewers: EricWF, mclow.lists

Subscribers: christof, dexonsmith, erikvanderpoel

Differential Revision: https://reviews.llvm.org/D48892

llvm-svn: 336866
2018-07-11 23:14:33 +00:00
Louis Dionne 195a499d63 Revert "[libc++] Replace uses of _LIBCPP_ALWAYS_INLINE by _LIBCPP_INLINE_VISIBILITY"
This reverts commit r336369. The commit had two problems:
1. __pbump was marked as _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY instead of
   _LIBCPP_INLINE_VISIBILITY, which lead to two symbols being added in the
   dylib and the check-cxx-abilist failing.

2. The LLDB tests started failing because they undefine
   `_LIBCPP_INLINE_VISIBILITY`. I need to figure out why they do that and
   fix the tests before we can go forward with this change.

llvm-svn: 336382
2018-07-05 18:41:50 +00:00
Louis Dionne 4a8f3f9948 [libc++] Replace uses of _LIBCPP_ALWAYS_INLINE by _LIBCPP_INLINE_VISIBILITY
Summary:
We never actually mean to always inline a function -- all the uses of
the macro I could find are actually attempts to control the visibility
of symbols. This is better described by _LIBCPP_INLINE_VISIBILITY, which
is actually always defined the same.

This change is orthogonal to the decision of what we're actually going
to do with _LIBCPP_INLINE_VISIBILITY -- it just simplifies things by
having one canonical way of doing things.

Reviewers: EricWF

Subscribers: christof, llvm-commits, dexonsmith, erikvanderpoel, mclow.lists

Differential Revision: https://reviews.llvm.org/D48892

llvm-svn: 336369
2018-07-05 16:49:38 +00:00
Pirama Arumuga Nainar 7aea360924 [Win32] Overload ==, != for locale_t and long long
Summary:
_is_chartype_l (needed for isxdigit_l) in MinGW compares locale_t and NULL.
NULL is 'long long' for 64-bit, and this results in ambiguous overloads when
compiled with Clang.  Define a concrete overload for the operators to fix the
ambiguity.

Reviewers: mstorsjo, EricWF, srhines, danalbert

Subscribers: christof, cfe-commits, ldionne

Differential Revision: https://reviews.llvm.org/D48749

llvm-svn: 336141
2018-07-02 20:11:15 +00:00
Peter Collingbourne acd1f4e738 Condition usage of locale stdlib functions on Android API version
Some *_l functions were not available in some versions of Bionic. This CL
checks that the NDK version supports the functions, and if not, falls back
on the corresponding functions that don't take a locale.

Patch by Tom Anderson!

Differential Revision: https://reviews.llvm.org/D46558

llvm-svn: 332543
2018-05-16 22:40:12 +00:00
Saleem Abdulrasool a4e874c516 support: add missing locale stubs for android L, M
The strto* family was introduced in android O (API Level 26).  However,
the support headers were adjusted to indicate that all locale aware
functions were added in L.  Provide stubs for the locale aware strto*
family until O.

llvm-svn: 330045
2018-04-13 18:14:57 +00:00
Dan Albert 9bc04e98c5 Stop using __strtonum_fallback on Android.
Fallback implementations are now provided by bionic when necessary,
which these may conflict with.

llvm-svn: 324534
2018-02-07 21:58:48 +00:00
Martin Storsjo 771edc7949 Allow to set locale on Windows.
Fix the problem PR31516 with setting locale on Windows by wrapping
_locale_t with a pointer-like class.

Reduces 74 test failures in std/localization test suite to 47 test
failures (on llvm clang, Visual Studio 2015). Number of test failures
doesn't depend on the platform (x86 or x64).

Patch by Andrey Khalyavin.

Differential Revision: https://reviews.llvm.org/D40181

llvm-svn: 318902
2017-11-23 10:38:18 +00:00
Martin Storsjo 837c5b6b13 Remove a broken win32 locale function redirection
One can't replace vsscanf(_l) with a sscanf(_l) that doesn't
take a va_list.

This has been untouched since it was added in SVN r140728, so
apparently it hasn't been used since. One reason for this mistake
originally might have been that there was no _vsscanf_l until MSVC
2015.

Since it's unused, just remove this define.

Differential Revision: https://reviews.llvm.org/D40323

llvm-svn: 318810
2017-11-21 22:41:15 +00:00
Martin Storsjo f8689b1be1 Redirect strftime_l to the locale-ignorant strftime on mingw
_strftime_l is only available in the numbered msvcrt versions
(starting from msvcr80.dll). In the default configuration, mingw
targets the unversioned msvcrt.dll - and there, _strftime_l is
not available (not even on windows 10).

If __MSVCRT_VERSION__ is set to a higher value (indicating a
non-default target and wanting to link to msvcrXX.dll), use the
correct function.

Differential Revision: https://reviews.llvm.org/D37468

llvm-svn: 312617
2017-09-06 05:07:25 +00:00
James Y Knight b6567b18c7 PR32476: __nop_locale_mgmt.h not needed with newlib 2.5+
Newlib 2.5 added the locale management functions, so it should not
include __nop_local_mgmt.h. This change adds proper guard around that
include statement.

For newlib 2.4, some releases contain these functions and some don't,
and they all have the same version numbers. This patch will work
properly with the initial "2.4.0" release which does not include these
functions and require __nop_local_mgmt.h.

This has been tested against newlib 2.2 and 2.5, and also sanity
checks against other different version numbers.

Patch by Martin J. O'Riordan and Walter Lee

Differential Revision: https://reviews.llvm.org/D32146

llvm-svn: 305394
2017-06-14 16:40:03 +00:00
Eric Fiselier 1ec026252b Fix Libc++ build with MinGW64
Summary: This patch corrects the build errors I encountered when building on MinGW64.

Reviewers: mati865, rnk, compnerd, smeenai, bcraig

Reviewed By: mati865, smeenai

Subscribers: martell, chapuni, cfe-commits

Differential Revision: https://reviews.llvm.org/D33082

llvm-svn: 304360
2017-05-31 22:14:05 +00:00
Eric Fiselier 80f8cfb37f Don't interfere with the __builtin_foo namespace under MSVC
This patch follows up on feedback received in the review for
D32988. Specifically that libc++ should not mess with the
__builtin namespace, and that libc++ should use __popcnt to implement
__pop_count under MSVC.

llvm-svn: 302731
2017-05-10 21:30:04 +00:00
Eric Fiselier 5d50aa3204 [libc++] Refactor Windows support headers.
Summary:
This patch refactors and tries to remove as much of the Windows support headers as possible. This is needed because they currently introduce super weird include cycles and dependencies between STL and libc headers.

The changes in this patch are:

* remove `support/win32/support.h` completely. The required parts have either been moved into `support/win32/msvc_support.h` (for `MSVC` only helpers not needed by Clang), or directly into their respective `foo.h` headers.

* Combine `locale_win32.h` and `locale_mgmt_win32.h` into a single headers, this header should only be included within `__locale` or `locale` to avoid include cycles.

* Remove the unneeded parts of `limits_win32.h` and re-name it to `limits_msvc_win32.h` since it's only needed by Clang.

I've tested this patch using Clang on Windows, but I suspect it might technically regress our non-existent support for MSVC. Is somebody able to double check?

This refactor is needed to support upcoming fixes to `<locale>` on Windows.



Reviewers: bcraig, rmaprath, compnerd, EricWF

Reviewed By: EricWF

Subscribers: majnemer, cfe-commits

Differential Revision: https://reviews.llvm.org/D32988

llvm-svn: 302727
2017-05-10 20:57:45 +00:00
Eric Fiselier 6d0dff294c Fix DLL import/export on Win32 locale helpers
llvm-svn: 302391
2017-05-08 00:37:31 +00:00
Petr Hosek d0e9481c55 [libcxx] Direct support for Fuchsia
Fuchsia's libc was forked from musl, but has evolved sufficiently
since then so it no longer makes sense to pretend it's musl. This
change implements direct support for Fuchsia rather than
piggybacking on musl support.

Differential Revision: https://reviews.llvm.org/D31970

llvm-svn: 300261
2017-04-13 21:29:21 +00:00
Shoaib Meenai 17af695f2b [libc++] Drop support for CRTs older than VS 2015
LLVM dropped support for Visual Studio versions older than 2015 quite
some time ago, so I consider it safe to drop libc++'s support for older
CRTs. The CRT in Visual Studio 2015 provides a lot of previously missing
functions, so targeting it requires less special casing.

Differential Revision: https://reviews.llvm.org/D31798

llvm-svn: 299743
2017-04-07 02:20:52 +00:00
Eric Fiselier 541f9e2830 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.

llvm-svn: 291286
2017-01-06 21:42:58 +00:00
Saleem Abdulrasool 86eebc5b65 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.

llvm-svn: 290924
2017-01-04 01:53:24 +00:00
Saleem Abdulrasool b2826a1ddc 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.

llvm-svn: 290910
2017-01-03 21:53:51 +00:00
Saleem Abdulrasool 8bcade547a locale: update ctype access for MSVC CRT 14+
Visual C++ 14 and newer split msvcrt into msvcrt and ucrt with flavours
of the ucrt for different environments.  This changed the access to the
ctype table by introducing the `__pctype_func` and `__pwctype_func`
accessors.  Use this rather than directly accessing `_ctype` which
allows us to be safer in threaded situations by going through the libc
locking.

llvm-svn: 290823
2017-01-02 18:41:48 +00:00
Shoaib Meenai c6f93e389e [libc++] Add missing locale aliases
Add underscore aliases for strtof_l and strtod_l. _strtold_l exists in
VS 2013 and above, so fix that definition as a drive-by fix.

Differential Revision: https://reviews.llvm.org/D25059

llvm-svn: 282681
2016-09-29 03:35:41 +00:00
Shoaib Meenai 4e14445e59 [libc++] Remove math_win32.h
Visual Studio 2013 and onward have all the required functions in their
CRT headers, and we don't support older versions anymore.

Differential Revision: https://reviews.llvm.org/D24879

llvm-svn: 282328
2016-09-24 06:27:28 +00:00
Dan Albert bc40821ee3 Fix signatures of fallback tow(upper|lower)_l.
Summary:
These functions take and return wint_t, not int:
http://pubs.opengroup.org/onlinepubs/9699919799/functions/towupper.html

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24743

llvm-svn: 281936
2016-09-19 20:42:57 +00:00
Dan Albert c991709f46 Replace __ANDROID__ with __BIONIC__.
Summary:
None of these checks are specific to Android devices. If libc++ was
used with Bionic on a normal Linux system these checks would still be
needed.

Reviewers: mclow.lists, EricWF

Subscribers: compnerd, tberghammer, danalbert, srhines, cfe-commits

Differential Revision: https://reviews.llvm.org/D24690

llvm-svn: 281921
2016-09-19 18:00:45 +00:00
Shoaib Meenai f6eea04cd1 [libc++] Avoid <memory> include in locale_win32.h
When `_LIBCPP_NO_EXCEPTIONS` is defined, we end up with compile errors
when targeting MSVCRT:

* Code includes `<new>`
* `<new>` includes `<cstdlib>` in order to get `abort`
* `<cstdlib>` includes `<stdlib.h>`, _before_ the `using ::abort`
* `<stdlib.h>` includes `locale_win32.h`
* `locale_win32.h` includes `<memory>`
* `<memory>` includes `<stdexcept>`
* `<stdexcept>` includes `<cstdlib` for `abort`, but that inclusion gets
  (correctly) ignored because of header guards
* `<stdexcept>` references `_VSTD::abort`, which isn't declared

The easiest solution is to make `locale_win32.h` not include `<memory>`,
by removing the use of `unique_ptr` and manually restoring the locale
instead.

Differential Revision: https://reviews.llvm.org/D24374

llvm-svn: 281641
2016-09-15 18:36:13 +00:00
Saleem Abdulrasool 0fbd53434d support: clean up MSVC support
Visual Studio 2013 (CRT version 12) added support for many C99 long long and
long double functions. Visual Studio 2015 (CRT version 14) increased C99 and C11
compliance further. Since we don't support Visual Studio versions older than
2013, we can considerably clean up the support header.

Patch by Shoaib Meenai!

llvm-svn: 280988
2016-09-08 20:52:48 +00:00
Eric Fiselier be13be47ba Implement LWG issue 1169. num_get not fully compatible with strto*
Use strtof and strtod for floats and doubles respectively instead of
always using strtold. The other parts of the change are already implemented
in libc++.

This patch also has a drive by fix to wbuffer_convert::underflow() which
prevents it from calling memmove(buff, null, 0).

llvm-svn: 273106
2016-06-19 06:58:22 +00:00
Ben Craig 57b8b1f75f Reorganize locale extension fallbacks. NFCI
The various _l locale extension functions originate from very
different places.  Some come from POSIX, some are BSD extensions,
and some are shared BSD and GLIBC extensions. This patch tries to
group the local extension reimplementations by source. This should
make it easier to make libcxx work with POSIX compliant C libraries
that lack these extensions.

The fallback locale functions are also useful on their own for other
lightweight platforms. Putting these fallback implementations in
support/xlocale should enable code sharing.

I have no access to a newlib system or an android system to build
and test with. I _do_ have access to a system without any of the _l
locale extensions though, and I was able to ensure that the new
__posix_l_fallback.h and __strtonum_fallback.h didn't have any massive
problems.

http://reviews.llvm.org/D17416

llvm-svn: 270213
2016-05-20 12:58:41 +00:00
Ben Craig 069b432bf7 Split locale management out of locale_win32. NFCI
For the locale refactor, the locale management functions (newlocale,
freelocale, uselocale) are needed in a separate header from the various _l
functions. This is because some platforms implement the _l functions in terms
of a locale switcher RAII helper, and the locale switcher RAII helper needs
the locale management functions. This patch helps pave the way by getting all
the functions in the right files, so that later diffs aren't completely
horrible.

Unfortunately, the Windows, Cygwin, and MinGW builds seemed to have
bit-rotted, so I wasn't able to test this completely. I don't think I made
things any worse than they already are though.

http://reviews.llvm.org/D17419

llvm-svn: 263020
2016-03-09 15:49:59 +00:00
Ben Craig b8aea04ef5 Split locale management out of newlib/xlocale.h. NFCI
This is one part of many of a locale refactor. See
http://reviews.llvm.org/D17146 for an idea of where this is going.

For the locale refactor, the locale management functions (newlocale,
freelocale, uselocale) are needed in a separate header from the various _l
functions. This is because some platforms implement the _l functions in terms
of a locale switcher RAII helper, and the locale switcher RAII helper needs
the locale management functions. This patch helps pave the way by getting all
the functions in the right files, so that later diffs aren't completely
horrible.

The "do-nothing" / "nop" locale functions are also useful on their own for
other lightweight platforms. Putting these nop implementations in
support/xlocale should enable code sharing.

Unfortunately, I have no access to a newlib system to build and test with, so
this change has been made blind.

Reviewed: http://reviews.llvm.org/D17382
llvm-svn: 261231
2016-02-18 17:40:16 +00:00
Ben Craig 217946da98 Split locale management out of ibm/xlocale.h. NFCI
This is one part of many of a locale refactor. See
http://reviews.llvm.org/D17146 for an idea of where this is going.

For the locale refactor, the locale management functions (newlocale,
freelocale, uselocale) are needed in a separate header from the various _l
functions. This is because some platforms implement the _l functions in terms
of a locale switcher RAII helper, and the locale switcher RAII helper needs
the locale management functions. This patch helps pave the way by getting all
the functions in the right files, so that later diffs aren't completely
horrible.

Unfortunately, I have no access to an AIX machine to build with, so this change
has been made blind. Also, the original author (Xing Xue) does not appear to
have a Phabricator account.

Reviewed: http://reviews.llvm.org/D17380
llvm-svn: 261230
2016-02-18 17:37:33 +00:00
Vasileios Kalintiris 8c58e92cd8 Add initial support for the MUSL C library.
Summary:
This patch adds the LIBCXX_LIBC_IS_MUSL cmake option to allow the
building of libcxx with the Musl C library. The option is necessary as
Musl does not provide any predefined macro in order to test for its
presence, like GLIBC. Most of the changes specify the correct path to
choose through the various #if/#else constructs in the locale code.

Depends on D13407.

Reviewers: mclow.lists, jroelofs, EricWF

Subscribers: jfb, tberghammer, danalbert, srhines, cfe-commits

Differential Revision: http://reviews.llvm.org/D13673

llvm-svn: 252457
2015-11-09 10:21:04 +00:00
Saleem Abdulrasool 66d4c6e78c cmath: account for MSVCRT 12.0 changes
MSVCRT 12.0 introduces better compatibility for C99. This includes a number of
math routines that were previously undefined. Use the crtversion.h header to
detect the version of MSVCRT being targeted and avoid re-declaring the
variables.

Since copysign has been introduced in MSVCRT, importing the definition via using
makes it difficult to provide overloads (due to minor differences between
throw () and noexcept. Avoid defining the overloads on newer MSVCRT
targets.

llvm-svn: 230867
2015-02-28 20:18:39 +00:00
Eric Fiselier fbbfd09214 Get libc++ building on Sun Solaris. Patch from C Bergstrom.
llvm-svn: 226947
2015-01-23 22:22:36 +00:00
Eric Fiselier 53deb607d9 Fixes to get libc++ building on sun solaris. Patch from C Bergstrom.
llvm-svn: 222794
2014-11-25 21:57:41 +00:00
Dan Albert cfc9229966 Fix win32 support header for mingw32.
These functions are defined as static in the mingw32 headers.

llvm-svn: 219140
2014-10-06 20:06:33 +00:00
Jonathan Roelofs 4f1561a5dd Support newlib as libc++'s C library [locale part]
http://reviews.llvm.org/D5385

llvm-svn: 218144
2014-09-19 20:09:12 +00:00
Marshall Clow b38f8f07c5 Add support for BIONIC C library (Android). Patch from Dan Albert
llvm-svn: 212724
2014-07-10 15:20:28 +00:00
Marshall Clow 354d39cabc Add license headers to a bunch of libc++ files that were missing them. No functionality change. Fixes 18291. Thanks to Nico for the bug report and the patch.
llvm-svn: 199400
2014-01-16 16:58:45 +00:00
Yaron Keren acb42aefd7 80 cols fixes.
llvm-svn: 198482
2014-01-04 09:27:39 +00:00
Yaron Keren f8f56755e0 Implement the functions: clz, clzl, clzll, ctz, ctzl, and ctzll
for libcxx when compiled with Visual C++ on Win32 and Win64.

clang and gcc (MinGW) compilers provide these implementations themselves.

llvm-svn: 198481
2014-01-04 08:56:00 +00:00