call_once is using relaxed atomic load to perform double-checked locking, which contains a data race. The fast-path load has to be an acquire atomic load.

Differential Revision: https://reviews.llvm.org/D24028

llvm-svn: 280621

Summary:
This patch allows threads not created using `std::thread` to use `std::notify_all_at_thread_exit` by ensuring the TL state has been initialized within `std::notify_all_at_thread_exit`.

Additionally this patch "fixes" a potential oddity in `__thread_local_pointer::reset(pointer)`, which would previously delete the old thread local data. However there should *never* be old thread local data because pthread *should* null it out on thread exit. Unfortunately it's possible that pthread failed to do this according to the spec:


> 
> Upon key creation, the value NULL shall be associated with the new key in all active threads. Upon thread creation, the value NULL shall be associated with all defined keys in the new thread.
> 
> An optional destructor function may be associated with each key value. At thread exit, if a key value has a non-NULL destructor pointer, and the thread has a non-NULL value associated with that key, the value of the key is set to NULL, and then the function pointed to is called with the previously associated value as its sole argument. The order of destructor calls is unspecified if more than one destructor exists for a thread when it exits.
> 
> If, after all the destructors have been called for all non-NULL values with associated destructors, there are still some non-NULL values with associated destructors, then the process is repeated. If, after at least {PTHREAD_DESTRUCTOR_ITERATIONS} iterations of destructor calls for outstanding non-NULL values, there are still some non-NULL values with associated destructors, implementations may stop calling destructors, or they may continue calling destructors until no non-NULL values with associated destructors exist, even though this might result in an infinite loop.

However if pthread fails to delete the value it is probably incorrect for us to do it. Destroying the value performs all of the "at thread exit" actions registered with it but we are way past "at thread exit".





Reviewers: mclow.lists, bcraig, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24159

llvm-svn: 280588

llvm-svn: 280585

Define _LIBCPP_SAFE_STATIC  __attribute__((require_constant_initialization)), and apply it to memory_resource

llvm-svn: 280561

Summary:
Currently a number of GCC warnings are emitted when building libc++. This patch fixes or ignores all of them. The primary changes are:

* Work around strict aliasing issues in `typeinfo::hash_code()` by using __attribute__((may_alias)). However I think a non-aliasing `hash_code()` implementation is possible. Further investigation needed.
* Add `_LIBCPP_UNREACHABLE()` to switch in `strstream.cpp` to avoid -Wpotentially-uninitialized.
* Fix -Wunused-value warning in `__all` by adding a void cast.
* Ignore -Wattributes for now. There are a number of real attribute issues when using GCC but enabling the warning is too noisy.
* Ignore -Wliteral-suffix since it warns about the use of reserved identifiers. Note Only GCC 7.0 supports disabling this warning.
* Ignore -Wc++14-compat since it warns about the sized new/delete overloads.



Reviewers: EricWF

Differential Revision: https://reviews.llvm.org/D24003

llvm-svn: 280007

Followon to r279744. Find the other exception types and make __throw_XXX routines (and call them).  Remove the generic __libcpp_throw routine, since no one uses it anymore.

llvm-svn: 279763

Add an _LIBCPP_NORETURN inline function named __throw_XXX for each exception type we define. They either construct and throw the exception, or abort() (if exceptions are disabled). Use these functions everywhere instead of assert()ing when exceptions are disabled. WARNING: This is a behavior change - but only with exceptions disabled.  Reviewed as: https://reviews.llvm.org/D23855.

llvm-svn: 279744

Summary:
This patch adds std::any by moving/adapting <experimental/any>.

This patch also implements the std::any parts of p0032r3 (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0032r3.pdf)
and LWG 2509 (http://cplusplus.github.io/LWG/lwg-defects.html#2509).

I plan to push it in a day or two if there are no comments.


Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D22733

llvm-svn: 278310

llvm-svn: 277456

If the last destruction is uncontended, skip the atomic store on
__shared_weak_owners_. This shifts some costs from normal
shared_ptr usage to weak_ptr uses.

https://reviews.llvm.org/D22470

llvm-svn: 277357

llvm-svn: 276511

llvm-svn: 275089

llvm-svn: 274419

llvm-svn: 274408

llvm-svn: 274407

llvm-svn: 274403

The end pointer should point to one past the end of the newly allocated
buffer.

rdar://problem/24265174

Differential Revision: http://reviews.llvm.org/D20334

llvm-svn: 274132

This patch makes the bind placeholders in std::placeholders both (1) const and
(2) constexpr (See below).

This is technically a breaking change for any code using the placeholders
outside of std::bind and depending on them being non-const. However I don't
think this will break any real world code.

(1) Previously the placeholders were non-const extern globals in all
dialects. This patch changes these extern globals to be const in all dialects.
Since the cv-qualifiers don't participate in name mangling for globals this
is an ABI compatible change.

(2) Make the placeholders constexpr in C++11 and beyond. Although LWG 2488 only
applies to C++17 I don't see any reason not to backport this change.

llvm-svn: 273824

llvm-svn: 273392

llvm-svn: 273391

This changes how filesystem::permissions(p, perms) handles symlinks. Previously
symlinks were not resolved by default instead only getting resolved when
"perms::resolve_symlinks" was used. After this change symlinks are resolved
by default and perms::symlink_nofollow must be given to change this.

This issue has not yet been moved to Ready status, and I will revert if it
doesn't get moved at the current meeting. However I feel confident that it
will and it's nice to have implementations when moving issues.

llvm-svn: 273328

* Fix non-null violation in strstream.cpp
  Overflow was calling memcpy with a null parameter and a size of 0.

* Fix std/atomics/atomics.flag/ tests:
  a.test_and_set() was reading from an uninitialized atomic, but wasn't
  using the value. The tests now clear the flag before performing the
  first test_and_set. This allows UBSAN to test that clear doesn't read
  an invalid value.

* Fix std/experimental/algorithms/alg.random.sample/sample.pass.cpp
  The tests were dereferencing a past-the-end pointer to an array so that
  they could do pointer arithmetic with it. Instead of dereference the iterator
  I changed the tests to use the special 'base()' test iterator method.

* Add -fno-sanitize=float-divide-by-zero to suppress division by zero UBSAN diagnostics.
  The tests that cause float division by zero are explicitly aware that they
  are doing that. Since this is well defined for IEEE floats suppress the warnings
  for now.

llvm-svn: 273107

* Fix passing a negative number as either tv_usec or tv_nsec. When file_time_type
  is negative and has a non-zero sub-second value we subtract 1 from tv_sec
  and make the sub-second duration positive.

* Detect and report when 'file_time_type' cannot be represented by time_t. This
  happens when using large/small file_time_type values with a 32 bit time_t.

There is more work to be done in the implementation. It should start to use
stat's st_mtim or st_mtimeval if it's provided as an extension. That way
we can provide a better resolution.

llvm-svn: 273103

As pointed out by @majnemer this is a better way to detect utimensat on all
platforms. The Apple specific guard is unneeded.

llvm-svn: 273093

llvm-svn: 273088

Summary:
Currently the  implementation of [util.smartptr.shared.atomic] is provided only when using Clang, and not with GCC. This is a relic of not having a GCC implementation of <atomic>, even though <atomic> isn't actually used in the implementation. This patch enables support for atomic shared_ptr functions when using GCC.

Note that this is not a header only change. Previously only Clang builds of libc++.so would provide the required symbols. There is no reason  for this restriction.
After this change both Clang and GCC builds should be binary compatible with each other WRT these symbols.


Reviewers: mclow.lists, rmaprath, EricWF

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D21407

llvm-svn: 273076

Currently 4 tests are failing on the ARM buildbot. To try and diagnose each
of the failures this patch does the following:

1) path.itr/iterator.pass.cpp
   * Temporarily print iteration sequence to see where its failing.

2) path.native.obs/string_alloc.pass.cpp
   * Remove test that ::new is not called when constructing a short string
     that requires a conversion. Since during the conversion global locale
     objects might be constructed.

3) fs.op.funcs/space.pass.cpp
   * Explicitly use uintmax_t in the implementation of space, hopefully
     preventing possible overflows.
   * Add additional tests that check for overflow is the calculation of the
     space_info values.
   * Add additional tests for the values returned from statfvs.

4) fs.op.funcs/last_write_time.pass.cpp
   * No changes made yet.

llvm-svn: 273075

r273060 didn't completely fix the issues in recursive_directory_iterator and
the tests. This patch follows up with more fixes

* Fix bug where recursive_directory_iterator::increment(ec) did not reset
  the error code if no failure occurred.

* Fix bad assertion in the recursive_directory_iterator::increment(ec) test
  that would only fire for certain iteration orders.

llvm-svn: 273070

There are two fixes in this patch:

* Fix bug where the constructor of recursive_directory_iterator did not reset
  the error code if no failure occurred.

* Fix tests were dependent on the iteration order of the test directories.

llvm-svn: 273060

Add the completed std::experimental::filesystem implementation and tests.
The implementation supports C++11 or newer.

The TS is built as part of 'libc++experimental.a'. Users of the TS need to
manually link this library. Building and testing the TS can be disabled using
the CMake option '-DLIBCXX_ENABLE_FILESYSTEM=OFF'.

Currently 'libc++experimental.a' is not installed by default. To turn on the
installation of the library use '-DLIBCXX_INSTALL_EXPERIMENTAL_LIBRARY=ON'.

llvm-svn: 273034

CloudABI has gained the mblen_l() function in the meantime that does
properly return whether the character set has shift-states (read:
never).

llvm-svn: 272886

Summary:
Android didn't gain GNU's strerror_r until Marshmallow. If we're
building libc++ against something older (we build the NDK library
against the oldest release we support, currently Gingerbread), fall
back to the POSIX version.

Reviewers: mclow.lists, EricWF

Subscribers: tberghammer, danalbert, srhines, cfe-commits

Differential Revision: http://reviews.llvm.org/D21402

llvm-svn: 272827

llvm-svn: 272641

llvm-svn: 272640

Summary:
system_error::message() uses `strerror` for the generic and system categories. This function is not thread safe.

The fix is to use `strerror_r`. It has been available since 2001 for GNU libc and since BSD 4.4 on FreeBSD/OS X.
On platforms with GNU libc the extended version is used which always returns a valid string, even if an error occurs.

In single-threaded builds `strerror` is still used.

See https://llvm.org/bugs/show_bug.cgi?id=25598

Reviewers: majnemer, mclow.lists

Subscribers: erik65536, cfe-commits, emaste

Differential Revision: http://reviews.llvm.org/D20903

llvm-svn: 272633

Some pthread implementations do not like being called pthead_join()
with the pthread_t argument set to 0, and causes a segfault. This
patch fixes this issue by validating the pthread_t argument before
invoking pthread_join().

NFC.

Differential revision: http://reviews.llvm.org/D20929

Change-Id: Ief817c57bd0e1f43cbaa03061e02417d6a180c38
Reviewers: EricWF
llvm-svn: 271634

llvm-svn: 268850

llvm-svn: 268839

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D20007

llvm-svn: 268829

This patch extracts out all the pthread dependencies of libcxx into the
new header __threading_support. The motivation is to make it easy to
re-target libcxx into platforms that do not support pthread.

Original patch from Fulvio Esposito (fulvio.esposito@outlook.com) - D11781

Applied with tweaks - D19412

Change-Id: I301111f0075de93dd8129416e06babc195aa936b
llvm-svn: 268734