Commit Graph

1643 Commits

Author SHA1 Message Date
Marshall Clow
575d6888eb Update the failure annotations for the uncaught_exceptions test. The underlying abi library on some Mac OS versions does not support the plural uncaught_exceptions, so libc++ emulates it from the singlar; this means it will only return 0 or 1.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@342063 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-12 16:59:09 +00:00
Marshall Clow
ec25143bbb Implement LWG #3017. list splice functions should use addressof
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@342057 91177308-0d34-0410-b5e6-96231b3b80d8
2018-09-12 14:46:17 +00:00
Marshall Clow
8220dac54c Last week, someone noted that a couple of the time_point member functions were not constexpr. I looked, and they were right. They were made constexpr in p0505, so I looked at all the other bits in that paper to make sure that I didn't miss anything else. There were a couple methods in the synopsis that should have been marked constexpr, but the code was correct.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340992 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-29 23:02:15 +00:00
Marshall Clow
c4f0f1eaa8 Use addressof instead of operator& in make_shared. Fixes PR38729. As a drive-by, make the same change in raw_storage_iterator (twice).
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340823 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-28 13:29:30 +00:00
Louis Dionne
cd04d45e3a [libc++] Fix handling of negated character classes in regex
Summary:
This commit fixes a regression introduced in r316095, where we don't match
inverted character classes when there's no negated characrers in the []'s.

rdar://problem/43060054

Reviewers: mclow.lists, timshen, EricWF

Subscribers: christof, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D50534

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340609 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-24 14:10:28 +00:00
Louis Dionne
39ad1d12c1 [libc++] Remove race condition in std::async
Summary:
The state associated to the future was set in one thread (with synchronization)
but read in another thread without synchronization, which led to a data race.

https://bugs.llvm.org/show_bug.cgi?id=38181
rdar://problem/42548261

Reviewers: mclow.lists, EricWF

Subscribers: christof, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D51170

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340608 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-24 14:00:59 +00:00
Eric Fiselier
c39fe08b20 Add diagnostics for min/max algorithms when a InputIterator is used.
These algorithms require a ForwardIterator or better. Ensure
we diagnose the contract violation at compile time instead of
of silently doing the wrong thing.

Further algorithms will be audited in upcoming patches.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340426 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-22 17:47:13 +00:00
Marshall Clow
4c90425692 Fix Bug 38644: multimap::clear() missing exception specifier. Add noexcept tests for all the containers that have clear().
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@340385 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-22 04:28:43 +00:00
Hubert Tong
aec9e0e5a2 [libc++] Use correct rand.eng.mers all-zeroes seed sequence fallback
Summary:
When a seed sequence would lead to having no non-zero significant bits
in the initial state of a `mersenne_twister_engine`, the fallback is to
flip the most significant bit of the first value that appears in the
textual representation of the initial state.

rand.eng.mers describes this as setting the value to be 2 to the power
of one less than w; the previous value encoded in the implementation,
namely one less than "2 to the power of w", is replaced by the correct
value in this patch.

Reviewers: mclow.lists, EricWF, jasonliu

Reviewed By: mclow.lists

Subscribers: mclow.lists, jasonliu, EricWF, christof, ldionne, cfe-commits

Differential Revision: https://reviews.llvm.org/D50736


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339969 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-16 23:56:54 +00:00
Marshall Clow
43d7c79aae Selectively import timespec_get into namespace std, since some C libraries don't have it. Reviewed as https://reviews.llvm.org/D50799
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339816 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-15 21:19:08 +00:00
Marshall Clow
a87d98049c Mark the at_exit and at_quick_exit tests as unsupported under C++98 an 03, since those calls were introduced in C++11. They're already guarded by an ifdef in the code, so this is a 'belt-and-suspenders' change.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339804 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-15 19:27:53 +00:00
Louis Dionne
a1b4766c47 [libcxx] Fix XFAILs for aligned allocation tests on older OSX versions
Summary:
Since r338934, Clang emits an error when aligned allocation functions are
used in conjunction with a system libc++ dylib that does not support those
functions. This causes some tests to fail when testing against older libc++
dylibs. This commit marks those tests as UNSUPPORTED, and also documents the
various reasons for the tests being unsupported.

Reviewers: vsapsai, EricWF

Subscribers: christof, dexonsmith, cfe-commits, mclow.lists, EricWF

Differential Revision: https://reviews.llvm.org/D50341

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339743 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-15 00:30:03 +00:00
Louis Dionne
010c53f892 [libc++] Disable failing C11 feature tests for <cfloat> and <float.h>
Summary:
Those tests are breaking the test bots. A Bugzilla has been filed to
make sure those tests are re-enabled: https://bugs.llvm.org/show_bug.cgi?id=38572

Reviewers: mclow.lists, EricWF

Subscribers: krytarowski, christof, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D50748

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339742 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-15 00:18:01 +00:00
Louis Dionne
4d5214346e [libc++] Add missing #include in C11 features tests
Summary:
These #includes are quite important, since otherwise any

    #if TEST_STD_VER > 14 && defined(TEST_HAS_C11_FEATURES)

checks are always false, and so we don't actually test for C11 support
in the standard library.

Reviewers: mclow.lists, EricWF

Subscribers: christof, dexonsmith, cfe-commits

Differential Revision: https://reviews.llvm.org/D50674

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339675 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-14 13:29:17 +00:00
Volodymyr Sapsai
6699cd385e [libcxx] Mark charconv tests as failing for previous libcxx versions.
<charconv> was added in r338479. Previous libcxx versions don't have
this functionality and corresponding tests should be failing.

Reviewers: mclow.lists, ldionne, EricWF

Reviewed By: ldionne

Subscribers: christof, dexonsmith, lichray, EricWF, cfe-commits

Differential Revision: https://reviews.llvm.org/D50543


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339451 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-10 17:03:47 +00:00
Billy Robert O'Neal III
5428c6b9d6 [libcxx] [test] Avoid -Wunused-local-typedef in node_handle.pass.cpp.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339218 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-08 04:24:47 +00:00
Billy Robert O'Neal III
d39a48c04b [libcxx] [test] Allow a standard library that implements LWG 1203 in istream.rvalue/rvalue.pass.cpp
(Still pending review at https://reviews.llvm.org/D47400 which has been open since may; will ask for forgiveness rather than permission :) )

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339214 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-08 00:49:02 +00:00
Billy Robert O'Neal III
76dae9f0ba [libcxx] [test] Remove nonportable locale assumption in basic.ios.members/narrow.pass.cpp
I'm not sure if libcxx is asserting UTF-8 here; but on Windows the full char value is always passed through in its entirety, since the default codepage is something like Windows-1252. The replacement character is only used for non-chars there; and that should be a more portable test everywhere.

(Still pending review at https://reviews.llvm.org/D47395 which has been open since may; will ask for forgiveness rather than permission :) )

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339213 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-08 00:47:29 +00:00
Billy Robert O'Neal III
d963dbfd40 [libcxx] [test] Remove asserts that <cstddef> and <stdexcept> are included by <bitset>
Reviewed as https://reviews.llvm.org/D50421

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339212 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-08 00:43:38 +00:00
Billy Robert O'Neal III
8989fab841 [libcxx] [test] Add missing <stdexcept> in several tests.
Reviewed as https://reviews.llvm.org/D50420

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339209 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-08 00:40:32 +00:00
Marshall Clow
de134800ae Mark LWG#2260 as complete. We already did the right thing, so I just added tests to ensure that we continue to DTRT.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338936 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-03 23:28:48 +00:00
Marshall Clow
3a225ef042 Update the changes to the array tests (that I committed yesterday) to use the test_comparison routines that I committed last week. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338797 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-03 00:47:12 +00:00
Marshall Clow
88f5d7a38b Implement P1023: constexpr comparison operators for std::array
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338668 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-02 02:11:06 +00:00
Marshall Clow
48282b6a2a Implement P0887: The identity metafunction
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338666 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-02 01:56:02 +00:00
Zhihao Yuan
80f0ca024a [libc++] Fix build failures after merging <charconv>
Summary:
- fix a stupid unit test typo
- add <charconv> symbols to Linux abilist

Reviewers: EricWF

Subscribers: christof, ldionne, cfe-commits

Differential Revision: https://reviews.llvm.org/D50130

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338486 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 05:21:26 +00:00
Zhihao Yuan
dc38e97601 [libc++][C++17] Elementary string conversions for integral types
Summary:
Major QoI considerations:

- The facility is backported to C++14, same as libstdc++.
- Efforts have been made to minimize the header dependencies.
- The design is friendly to the uses of MSVC intrinsics (`__emulu`, `_umul128`, `_BitScanForward`, `_BitScanForward64`) but not implemented; future contributions are welcome.

Thanks to Milo Yip for contributing the implementation of `__u64toa` and `__u32toa`.

References:
 https://wg21.link/p0067r5
 https://wg21.link/p0682r1

Reviewers: mclow.lists, EricWF

Reviewed By: mclow.lists

Subscribers: ldionne, Quuxplusone, christof, mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D41458

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338479 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 02:38:30 +00:00
Erik Pilkington
36fc737189 First half of C++17's splicing maps and sets
This commit adds a node handle type, (located in __node_handle), and adds
extract() and insert() members to all map and set types, as well as their
implementations in __tree and __hash_table.

The second half of this feature is adding merge() members, which splice nodes
in bulk from one container into another. This will be committed in a follow-up.

Differential revision: https://reviews.llvm.org/D46845

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338472 91177308-0d34-0410-b5e6-96231b3b80d8
2018-08-01 01:33:38 +00:00
Marshall Clow
ea96e3a707 Final bit of P0063 - make sure that aligned_alloc is available when the underlying C library supports it
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338457 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-31 23:39:12 +00:00
Marshall Clow
4983a7a649 Test for the presence of a bunch of new macros for c++17. These macros come from C11. Part of P0063
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338454 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-31 23:29:06 +00:00
Marshall Clow
8a16d40991 import timespec and timespec_get into namespace std if we're under c++17 or later AND the underlying C library has them. Fixes PR#38220, but doesn't implement all of P0063 yet.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338419 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-31 19:25:00 +00:00
Tim Shen
379cbeb1a2 [libcxx] fix >> 42 UB in <experimental/simd>
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338325 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-30 23:05:40 +00:00
Tim Shen
154f393a5c Re-apply "[libcxx] implement <simd> ABI for Clang/GCC vector extension, constructors, copy_from and copy_to."
...with proper guarding #ifdefs for unsupported C++11.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338318 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-30 22:27:38 +00:00
Tim Shen
b6244cf5af Revert "[libcxx] implement <simd> ABI for Clang/GCC vector extension, constructors, copy_from and copy_to."
This reverts commit r338309.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338316 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-30 22:21:22 +00:00
Tim Shen
373299533a [libcxx] implement <simd> ABI for Clang/GCC vector extension, constructors, copy_from and copy_to.
Summary:
This patch adds a new macro _LIBCPP_HAS_NO_VECTOR_EXTENSION for detecting
whether a vector extension (\_\_attribute\_\_((vector_size(num_bytes)))) is
available.

On the top of that, this patch implements the following API:
* all constructors
* operator[]
* copy_from
* copy_to

It also defines simd_abi::native to use vector extension, if available.
In GCC and Clang, certain values with vector extension are passed by registers,
instead of memory.

Based on D41148.

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits, MaskRay, lichray, sanjoy

Differential Revision: https://reviews.llvm.org/D41376

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338309 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-30 21:23:13 +00:00
Eric Fiselier
a0866c5fb5 Implement <filesystem>
This patch implements the <filesystem> header and uses that
to provide <experimental/filesystem>.

Unlike other standard headers, the symbols needed for <filesystem>
have not yet been placed in libc++.so. Instead they live in the
new libc++fs.a library. Users of filesystem are required to link this
library. (Also note that libc++experimental no longer contains the
definition of <experimental/filesystem>, which now requires linking libc++fs).

The reason for keeping <filesystem> out of the dylib for now is that
it's still somewhat experimental, and the possibility of requiring an
ABI breaking change is very real. In the future the symbols will likely
be moved into the dylib, or the dylib will be made to link libc++fs automagically).

Note that moving the symbols out of libc++experimental may break user builds
until they update to -lc++fs. This should be OK, because the experimental
library provides no stability guarantees. However, I plan on looking into
ways we can force libc++experimental to automagically link libc++fs.

In order to use a single implementation and set of tests for <filesystem>, it
has been placed in a special `__fs` namespace. This namespace is inline in
C++17 onward, but not before that. As such implementation is available
in C++11 onward, but no filesystem namespace is present "directly", and
as such name conflicts shouldn't occur in C++11 or C++14.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338093 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-27 03:07:09 +00:00
Eric Fiselier
cff3d7b202 Correct comment about stat truncating st_mtimespec to seconds
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338000 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-26 03:42:25 +00:00
Eric Fiselier
6655abbc33 Workaround OS X 10.11 behavior where stat truncates st_mtimespec to seconds.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337998 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-26 03:28:48 +00:00
Eric Fiselier
8940394a74 Add print statements to help debugging
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337991 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-26 01:10:50 +00:00
Eric Fiselier
0c29afae93 Remove test which shouldn't have been committed
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337971 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-25 21:58:37 +00:00
Eric Fiselier
81872e95bf [libc++] Use __int128_t to represent file_time_type.
Summary:
The ``file_time_type`` time point is used to represent the write times for files.
Its job is to act as part of a C++ wrapper for less ideal system interfaces. The
underlying filesystem uses the ``timespec`` struct for the same purpose.

However, the initial implementation of ``file_time_type`` could not represent
either the range or resolution of ``timespec``, making it unsuitable. Fixing
this requires an implementation which uses more than 64 bits to store the
time point.

I primarily considered two solutions: Using ``__int128_t`` and using a
arithmetic emulation of ``timespec``. Each has its pros and cons, and both
come with more than one complication.

However, after a lot of consideration, I decided on using `__int128_t`. This patch implements that change.

Please see the [FileTimeType Design Document](http://libcxx.llvm.org/docs/DesignDocs/FileTimeType.html) for more information.

Reviewers: mclow.lists, ldionne, joerg, arthur.j.odwyer, EricWF

Reviewed By: EricWF

Subscribers: christof, K-ballo, cfe-commits, BillyONeal

Differential Revision: https://reviews.llvm.org/D49774

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337960 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-25 20:51:49 +00:00
Eric Fiselier
8410c8170a Fix bugs in create_directory implementation.
Libc++ was incorrectly reporting an error when the target of create_directory
already exists, but was not a directory. This behavior is not specified
in the most recent standard, which says no error should be reported.

Additionally, libc++ failed to report an error when the attribute directory
path didn't exist or didn't name a directory. This has been fixed as well.

Although it's not clear if we should call status or symlink_status on the
attribute directory. This patch chooses to still call status.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337888 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-25 04:46:32 +00:00
Eric Fiselier
2493db4b26 Make <experimental/filesystem> explicitly require C++11.
Previously the <experimental/filesystem> didn't guard its
contents in any dialect. However, the implementation implicitly
requires at least C++11, and the tests have always been marked
unsupported in C++03. This patch puts a header guard around the
contents to avoid exposing them before C++11.

Additionally, it replaces all of the usages of _NOEXCEPT or
_LIBCPP_CONSTEXPR with the keyword directly, since we can
expect the compiler to implement those by now.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337884 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-25 03:41:31 +00:00
Marshall Clow
dfd0874465 Disable 'suggest braces' warnings for std::array in tests
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337808 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-24 03:41:36 +00:00
Marshall Clow
fbd3e84fa1 Implement <span>. Reviewed as https://reviews.llvm.org/D49338
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337804 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-24 03:01:02 +00:00
Eric Fiselier
f581ed2017 Fix accidentally removed test.
When adding the new tests for the filesystem_error::what method,
I incorrectly removed a test case and replaced it with something else.

This patch restores that test case

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337764 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-23 22:39:56 +00:00
Eric Fiselier
0ddb77a467 Implement filesystem_error::what() and improve reporting.
This patch implements the `what()` for filesystem errors. The message
includes the 'what_arg', any paths that were specified, and the
error code message.

Additionally this patch refactors how errors are created, making it easier
to report them correctly.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337664 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-23 02:00:52 +00:00
Eric Fiselier
1061b65e6e fix test failures with older clang versions
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337658 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-22 20:50:16 +00:00
Eric Fiselier
70c866bfc1 Implement a better copy_file.
This patch improves both the performance, and the safety of the
copy_file implementation.

The performance improvements are achieved by using sendfile on
Linux and copyfile on OS X when available.

The TOCTOU hardening is achieved by opening the source and
destination files and then using fstat to check their attributes to
see if we can copy them.

Unfortunately for the destination file, there is no way to open
it without accidentally creating it, so we first have to use
stat to determine if it exists, and if we should copy to it.
Then, once we're sure we should try to copy, we open the dest
file and ensure it names the same entity we previously stat'ed.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337649 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-22 02:00:53 +00:00
Eric Fiselier
e274f439c6 [libc++] Implement Directory Entry Caching -- Sort of.
Summary:
This patch implements directory_entry caching *almost* as specified in P0317r1. However, I explicitly chose to deviate from the standard as I'll explain below.

The approach I decided to take is a fully caching one. When `refresh()` is called, the cache is populated by calls to `stat` and `lstat` as needed.
During directory iteration the cache is only populated with the `file_type` as reported by `readdir`.
The cache can be in the following states:

* `_Empty`: There is nothing in the cache (likely due to an error)
* `_IterSymlink`: Created by directory iteration when we walk onto a symlink only the symlink file type is known.
* `_IterNonSymlink`: Created by directory iteration when we walk onto a non-symlink. Both the regular file type and symlink file type are known.
* `_RefreshSymlink` and `_RefreshNonSymlink`: A full cache created by `refresh()`.  This case includes dead symlinks.
* `_RefreshSymlinkUnresolved`: A partial cache created by refresh when we fail to resolve the file pointed to by a symlink (likely due to permissions). Symlink attributes are cached, but attributes about the linked entity are not.

As mentioned, this implementation purposefully deviates from the standard. According to some readings of the specification, and the Windows filesystem implementation, the constructors and modifiers which don't pass an `error_code` must throw when the `directory_entry` points to a entity which doesn't exist. or when attribute resolution fails for another reason. 

@BillyONeal  has proposed a more reasonable set of requirements, where modifiers other than refresh ignore errors. This is the behavior libc++ currently implements, with the expectation some form of the new language will be accepted into the standard.

Some additional semantics which differ from the Windows implementation:

1. `refresh` will not throw when the entry doesn't exist. In this case we can still meet the functions specification, so we don't treat it as an error.
2. We don't clear the path name when a constructor fails via refresh (this will hopefully be changed in the standard as well).

It should be noted that libstdc++'s current implementation has the same behavior as libc++, except for point (2).

If the changes to the specification don't get accepted, we'll be able to make the changes later.

[1] http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0317r1.html

Reviewers: mclow.lists, gromer, ldionne, aaron.ballman

Subscribers: BillyONeal, christof, cfe-commits

Differential Revision: https://reviews.llvm.org/D49530

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337516 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-20 01:22:32 +00:00
Marshall Clow
9765ed0367 Fix a couple of 'unused variable' warnings in a vector test. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@337016 91177308-0d34-0410-b5e6-96231b3b80d8
2018-07-13 16:26:16 +00:00