Commit Graph

175 Commits

Author SHA1 Message Date
Eric Fiselier
5fd0d08f72 Fix demangle.h on Windows
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292028 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 20:21:18 +00:00
Eric Fiselier
157fd34124 [libc++][CMake] Use debug MSVC runtimes when libc++ is built in debug mode
Summary: This patch allows libc++ to be built against the debug MSVC runtimes instead of just the release ones.

Reviewers: rnk, majnemer, compnerd, smeenai

Subscribers: mgorny, cfe-commits

Differential Revision: https://reviews.llvm.org/D28725

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@292006 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-14 07:54:39 +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
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
Eric Fiselier
5616ee5bac Get all tuple tests passing on Windows
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@291311 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-07 00:10:42 +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
Asiri Rathnayake
e29d9ff936 [libcxx] Fix testing of the externally-threaded library build
after r290850

Before r290850, building libcxx with -DLIBCXX_HAS_EXTERNAL_THREAD_API=ON had two
uses:
  - Allow platform vendors to plug-in an __external_threading header which
    should take care of the entire threading infrastructure of libcxx

  - Allow testing of an externally-threaded library build; where the thread API
    is declared using pthread data structures, and the implementation of this
    API is provided as a separate library (test/support/external_threads.cpp)
   and linked-in when running the test suite.

r290850 breaks the second use case (pthread data structures are no longer
available). This patch re-stores the ability to build+test an
externally-threaded library variant on a pthread based system.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290878 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-03 11:32:31 +00:00
Saleem Abdulrasool
1d19237a46 threading_support: refactor for Win32 threading
Refactor the header to allow us to implement alternate threading models
with alternate data structures.  Take the opportunity to clang-format
the area.  This will allow us to avoid re-declaring the interfaces for
Win32 threading.  NFC

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290850 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-03 02:00:31 +00:00
Eric Fiselier
47257c4a7d Add tests for unordered container tests and std::string
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290655 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-28 05:53:01 +00:00
Eric Fiselier
3678f7d6ee Fix another unused warning
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290470 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-24 00:28:19 +00:00
Eric Fiselier
0e5ebbc77c Fix unused parameters and variables
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@290459 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-23 23:37:52 +00:00
Eric Fiselier
9663ee4d4f Revert r289727 due to PR31384
This patch reverts the changes to tuple which fixed construction from
types derived from tuple. It breaks the code mentioned in llvm.org/PR31384.
I'll follow this commit up with a test case.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289773 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-15 06:34:54 +00:00
Eric Fiselier
bad1d6c248 Fix PR31378 - std::list::remove should not require a default constructible allocator.
In list::remove we collect the nodes we're removing in a seperate
list instance. However we construct this list using the default
constructor which default constructs the allocator. However allocators
are not required to be default constructible. This patch fixes the
construction of the second list.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289735 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-14 22:48:38 +00:00
Eric Fiselier
18e56b438e [libcxx] Fix tuple construction/assignment from types derived from tuple/pair/array.
Summary:
The standard requires tuple have the following constructors:
```
tuple(tuple<OtherTypes...> const&);
tuple(tuple<OtherTypes...> &&);
tuple(pair<T1, T2> const&);
tuple(pair<T1, T2> &&);
tuple(array<T, N> const&);
tuple(array<T, N> &&);
```
However libc++ implements these as a single constructor with the signature:
```
template <class TupleLike, enable_if_t<__is_tuple_like<TupleLike>::value>>
tuple(TupleLike&&);
```

This causes the constructor to reject types derived from tuple-like types; Unlike if we had all of the concrete overloads, because they cause the derived->base conversion in the signature.

This patch fixes this issue by detecting derived types and the tuple-like base they are derived from. It does this by creating an overloaded function with signatures for each of tuple/pair/array and checking if the possibly derived type can convert to any of them.

This patch fixes [PR17550]( https://llvm.org/bugs/show_bug.cgi?id=17550)

This patch 

Reviewers: mclow.lists, K-ballo, mpark, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D27606

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289727 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-14 22:22:38 +00:00
Eric Fiselier
11f64dcc58 Fix undefined behavior in container swap tests.
These swap tests were swapping non-POCS non-equal allocators which
is undefined behavior. This patch changes the tests to use allocators
which compare equal. In order to test that the allocators were not
swapped I added an "id" field to test_allocator which does not
participate in equality but does propagate across copies/swaps.

This patch is based off of D26623 which was submitted by STL.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289358 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-11 03:41:12 +00:00
Eric Fiselier
e5bca2ba66 Fix more uses of dynamic exception specifications in C++17
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289356 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-11 02:47:36 +00:00
Eric Fiselier
b61c998ece Fix count_new.hpp to work w/o dynamic exception specifications
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289355 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-11 02:20:17 +00:00
Stephan T. Lavavej
aa1d62b4af [libcxx] [test] Add LIBCPP_ASSERT_NOEXCEPT/LIBCPP_ASSERT_NOT_NOEXCEPT, remove an unused variable.
test/support/test_macros.h
For convenience/greppability, add macros for libcxx-specific static_asserts about noexceptness.

(Moving the definitions of ASSERT_NOEXCEPT/ASSERT_NOT_NOEXCEPT isn't technically necessary
because they're macros, but I think it's better style to define stuff before using it.)

test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
There was a completely unused `TrackedCallable obj;`.

apply() isn't depicted with conditional noexcept in C++17.

test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
Now that we have LIBCPP_ASSERT_NOEXCEPT, use it.

Fixes D27622.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289264 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-09 19:53:08 +00:00
Eric Fiselier
e386ad3090 Refactor uses_allocator test types for upcoming fixes
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289197 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-09 09:51:09 +00:00
Eric Fiselier
11715ba8e2 Put C++ ABI headers in a special build directory instead of the top level.
This patch changes where the C++ ABI headers are put during the build. Previously
    they were put in the top level include directory (not the libc++ header directory).
    However that just polutes the top level directory. Instead this patch creates a special
    directory to put them in. The reason they can't be put under c++/v1 until after the build
    is because libc++ uses the in-source headers, so we can't add the include path of the libc++
    headers in the object dir.

    Additionally this patch teaches the test suite how to find the ABI headers,
    and adds a demangling utility to help debug tests with.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289195 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-09 09:31:01 +00:00
Stephan T. Lavavej
ae5809a70c [libcxx] [test] D27268: Fix MSVC x64 warning C4267 "conversion from 'size_t' to 'int' [or 'unsigned int'], possible loss of data", part 2/4.
Use static_cast<int> when storing size_t in int (or passing size_t to int).

Also, remove a spurious semicolon in test/support/archetypes.hpp.

test/support/count_new.hpp
Additionally, change data members (and parameters) to size_t.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@288752 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-06 01:14:43 +00:00
Stephan T. Lavavej
e2dbcaf969 [libcxx] [test] D27266: Remove spurious semicolons.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@288750 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-06 01:14:06 +00:00
Eric Fiselier
e041941007 Fix __hash_table::max_size() on 32 bit systems
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287749 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-23 09:16:12 +00:00
Eric Fiselier
ef3060ef96 [libcxx] Fix max_size() across all containers
Summary: The `max_size()` method of containers should respect both the allocator's reported `max_size` and the range of the `difference_type`. This patch makes all containers choose the smallest of those two values.

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D26885

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287729 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-23 01:18:56 +00:00
Eric Fiselier
0373708cdc Add <variant> tests but disable them for libc++
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287728 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-23 01:02:51 +00:00
Eric Fiselier
388ffe1db1 Adjust uses_alloc_types helpers for later changes
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@287512 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-21 00:41:32 +00:00
Stephan T. Lavavej
e619862dbf [libcxx] [test] Replace _LIBCPP_STD_VER with TEST_STD_VER.
This replaces every occurrence of _LIBCPP_STD_VER in the tests with
TEST_STD_VER. Additionally, for every affected
file, #include "test_macros.h" is being added explicitly if it wasn't
already there.

https://reviews.llvm.org/D26294

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@286007 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-04 20:26:59 +00:00
Roger Ferrer Ibanez
1c0757acd1 Fix archetypes.hpp under libcpp-no-extensions and std level < 14
Under -fno-exceptions TEST_THROW becomes abort / __builtin_abort which returns
void. This causes a type mismatch in the conditional operator when testing the
library in C++98,03,11 modes.

Use a comma operator to workaround this problem.

Differential Revision: https://reviews.llvm.org/D26147



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@285572 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-31 14:14:13 +00:00
Casey Carter
b035d8f064 Silence unused parameter warnings in archetypes.hpp
Reviewed at: https://reviews.llvm.org/D25958



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@285213 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-26 17:22:25 +00:00
Eric Fiselier
317120240b Fix unreferenced parameters. Patch from STL@microsoft.com
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284942 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-23 18:52:58 +00:00
Eric Fiselier
846edfb837 Update issue status for LWG 2744
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284322 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-16 02:51:50 +00:00
Eric Fiselier
c69d8ca589 Correctly grant rebound limited_allocators friendship.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284006 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 11:35:37 +00:00
Eric Fiselier
de8e3d3a4f Unbreak C++03 build
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@284004 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 11:20:27 +00:00
Eric Fiselier
4775578c61 Remove usages of _ALIGNAS_TYPE
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283999 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 10:19:48 +00:00
Eric Fiselier
6f6a9607c2 Fix more C++11 constexpr issues in the tests
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283996 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 09:48:44 +00:00
Eric Fiselier
159b45f505 Fix nasty_containers.hpp for other stdlibs
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283994 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 09:31:26 +00:00
Eric Fiselier
bf148f02bc Fix use of C++14 constexpr in C++11
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283993 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 09:20:58 +00:00
Eric Fiselier
028a2091ea Protect special members of NullBase archetype to avoid exposing them
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283983 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 08:09:22 +00:00
Eric Fiselier
35ce4859dd Implement N4606 optional
Summary:
Adapt implementation of Library Fundamentals TS optional into an implementation of N4606 optional.

  - Update relational operators per http://wg21.link/P0307
  - Update to requirements of http://wg21.link/P0032
  - Extension: Implement trivial copy/move construction/assignment for `optional<T>` when `T` is trivially copyable.

Audit P/Rs for optional LWG issues:
  - 2756 "C++ WP optional<T> should 'forward' T's implicit conversions" Implemented, which also resolves 2753 "Optional's constructors and assignments need constraints" (modulo my refusal to explicitly delete the move operations, which is a design error that I'm working on correcting in the 2756 P/R).
  - 2736 "nullopt_t insufficiently constrained" Already conforming. I've added a test ensuring that `nullopt_t` is not copy-initializable from an empty braced-init-list, which I believe is the root intent of the issue, to avoid regression.
  - 2740 "constexpr optional<T>::operator->" Already conforming.
  - 2746 "Inconsistency between requirements for emplace between optional and variant" No P/R, but note that the author's '"suggested resolution" is already implemented.
  - 2748 "swappable traits for optionals" Already conforming.
  - 2753 "Optional's constructors and assignments need constraints" Implemented.

Most of the work for this patch was done by Casey Carter @ Microsoft. Thank you Casey!



Reviewers: mclow.lists, CaseyCarter, EricWF

Differential Revision: https://reviews.llvm.org/D22741

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283980 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 07:46:20 +00:00
Eric Fiselier
ead5d404cc Revert Add <optional>. Will recommit with better commit message
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283978 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 06:48:31 +00:00
Eric Fiselier
fbc80168bb Add <optional> header.
This patch is largely thanks to Casey Carter @ Microsoft. He did the initial
work of porting our experimental implementation and tests over to namespace
std.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283977 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-12 06:45:11 +00:00
Eric Fiselier
ef9e52bc90 Add missing include in test_allocator.h
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283632 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-08 00:57:56 +00:00
Eric Fiselier
124ed406e5 [libc++] Fix stack_allocator
Summary:
To quote STL the problems with stack allocator are"

>"stack_allocator<T, N> is seriously nonconformant to N4582 17.6.3.5 [allocator.requirements].
> First, it lacks a rebinding constructor. (The nested "struct rebind" isn't sufficient.)
> Second, it lacks templated equality/inequality.
> Third, it completely ignores alignment.
> Finally, and most severely, the Standard forbids its existence. Allocators are forbidden from returning memory "inside themselves". This requirement is implied by the Standard's requirements for rebinding and equality. It's permitted to return memory from a separate buffer object on the stack, though."

This patch attempts to address all of those issues.

First, instead of storing the buffer inside the allocator I've change `stack_allocator` to accept the buffer as an argument.

Second, in order to fix rebinding I changed the parameter list from `<class T, size_t NumElements>` to `<class T, size_t NumBytes>`. This allows allocator rebinding
between types that have different sizes. 

Third, I added copy and rebinding constructors and assignment operators.

And finally I fixed the allocation logic to always return properly aligned storage.



Reviewers: mclow.lists, howard.hinnant, STL_MSFT

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D25154

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283631 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-08 00:56:22 +00:00
Eric Fiselier
2c429bee79 Fix various issues in std::any and the related tests.
* Fix self-swap. Patch from Casey Carter.

* Remove workarounds and tests for types with deleted move constructors. This
  was originally added as part of a LWG proposed resolution that has since
  changed.

* Re-apply most recent PR for LWG 2769.

* Re-apply most recent PR for LWG 2754. Specifically fix the SFINAE checks to
  use the decayed type.

* Fix tests to allow moved-from std::any's to have a non-empty state. This is
  the behavior of MSVC's std::any.

* Various whitespace and test fixes.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283606 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-07 21:27:45 +00:00
Eric Fiselier
45a9570f5d Remove MSVC workarounds. Patch from STL@microsoft.com
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283580 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-07 18:51:33 +00:00
Eric Fiselier
8f972f6538 [libcxx] [test] Guard __has_include usage with a macro
Summary: There's a macro scheme already being used for __has_feature etc. Use it for __has_include too, which makes MSVC happy (it doesn't support __has_include yet, and unguarded use explodes horribly).

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D25251

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283260 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-04 21:25:51 +00:00
Eric Fiselier
cdac787ae8 Replace test_throw.h header with a single test macro
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@283030 91177308-0d34-0410-b5e6-96231b3b80d8
2016-10-01 10:34:13 +00:00
Eric Fiselier
4e3e15ad99 [libc++] Remove various C++03 feature test macros
Summary:
Libc++ still uses per-feature configuration macros when configuring for C++11. However libc++ requires a feature-complete C++11 compiler so there is no reason to check individual features. This patch starts the process of removing the feature specific macros and replacing their usage with `_LIBCPP_CXX03_LANG`.

This patch removes the __config macros:

* _LIBCPP_HAS_NO_TRAILING_RETURN
* _LIBCPP_HAS_NO_TEMPLATE_ALIASES
* _LIBCPP_HAS_NO_ADVANCED_SFINAE
* _LIBCPP_HAS_NO_DEFAULT_FUNCTION_TEMPLATE_ARGS
* _LIBCPP_HAS_NO_STATIC_ASSERT

As a drive I also changed our C++03 static_assert to use _Static_assert if available.

I plan to commit this without review if nobody voices an objection.

Reviewers: mclow.lists

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24895

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@282347 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-25 03:34:28 +00:00
Asiri Rathnayake
040945b81f [libcxx] Introduce an externally-threaded libc++ variant.
This patch further decouples libc++ from pthread, allowing libc++ to be built
against other threading systems. There are two main use cases:

- Building libc++ against a thread library other than pthreads.

- Building libc++ with an "external" thread API, allowing a separate library to
  provide the implementation of that API.

The two use cases are quite similar, the second one being sligtly more
de-coupled than the first. The cmake option LIBCXX_HAS_EXTERNAL_THREAD_API
enables both kinds of builds. One needs to place an <__external_threading>
header file containing an implementation of the "libc++ thread API" declared
in the <__threading_support> header.

For the second use case, the implementation of the libc++ thread API can
delegate to a custom "external" thread API where the implementation of this
external API is provided in a seperate library. This mechanism allows toolchain
vendors to distribute a build of libc++ with a custom thread-porting-layer API
(which is the "external" API above), platform vendors (recipients of the
toolchain/libc++) are then required to provide their implementation of this API
to be linked with (end-user) C++ programs.

Note that the second use case still requires establishing the basic types that
get passed between the external thread library and the libc++ library
(e.g. __libcpp_mutex_t). These cannot be opaque pointer types (libc++ sources
won't compile otherwise). It should also be noted that the second use case can
have a slight performance penalty; as all the thread constructs need to cross a
library boundary through an additional function call.

When the header <__external_threading> is omitted, libc++ is built with the
"libc++ thread API" (declared in <__threading_support>) as the "external" thread
API (basic types are pthread based). An implementation (pthread based) of this
API is provided in test/support/external_threads.cpp, which is built into a
separate DSO and linked in when running the libc++ test suite. A test run
therefore demonstrates the second use case (less the intermediate custom API).

Differential revision: https://reviews.llvm.org/D21968

Reviewers: bcraig, compnerd, EricWF, mclow.lists

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@281179 91177308-0d34-0410-b5e6-96231b3b80d8
2016-09-11 21:46:40 +00:00