Commit Graph

411 Commits

Author SHA1 Message Date
Richard Smith ae62727a28 Remove libc++ checks and workarounds for unsupported old versions of GCC (<4.9).
Differential Revision: https://reviews.llvm.org/D61107

llvm-svn: 359232
2019-04-25 20:02:10 +00:00
Martin Storsjo 2bbb7feda8 Set _LIBCPP_DLL_VIS on _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS in MinGW mode
Contrary to MSVC, MinGW compilers wants the dllexport attribute on
the declaration of an explicit template instantiation, not on the
definition.

Differential Revision: https://reviews.llvm.org/D61123

llvm-svn: 359227
2019-04-25 19:46:28 +00:00
Eric Fiselier 2fc5a786be Add std::is_constant_evaluated.
Clang recently added __builtin_is_constant_evaluated() and GCC 9.0
has it as well.

This patch adds support for it in libc++.

llvm-svn: 359119
2019-04-24 17:54:25 +00:00
Louis Dionne 81875a67b0 [libc++] Use the no_destroy attribute to avoid destroying debug DB statics
Summary:
Otherwise, we can run into problems when the program has static variables
that need to use the debug database during their deinitialization, if
the debug DB has already been deinitialized.

Reviewers: EricWF

Subscribers: christof, jkorous, dexonsmith, libcxx-commits

Tags: #libc

Differential Revision: https://reviews.llvm.org/D60830

llvm-svn: 358602
2019-04-17 18:20:19 +00:00
Marshall Clow 1931c4306a Fix PR#35967: '<regex> syntax_option_type is not a proper bitmask' Sadly, this is an ABI break, so it's only available if you define either '_LIBCPP_ABI_VERSION > 2' or '_LIBCPP_ABI_UNSTABLE' or '_LIBCPP_ABI_REGEX_CONSTANTS_NONZERO' and rebuild your dylib.
llvm-svn: 357190
2019-03-28 17:30:23 +00:00
Louis Dionne fa0573027f [libc++] Mark <filesystem> as unavailable on Apple platforms using pragmas
Summary:
Also add the corresponding XFAILs to tests that require filesystem.
The approach taken to mark <filesystem> as unavailable in this patch
is to mark all the header as unavailable using #pragma clang attribute.
Marking each declaration using the attribute is more intrusive and
does not provide a lot of value right now because pretty much everything
in <filesystem> requires dylib support, often transitively.

This is an alternative to https://reviews.llvm.org/D59093.
A similar (but partial) patch was already applied in r356558.

Reviewers: mclow.lists, EricWF, serge-sans-paille

Subscribers: christof, jkorous, dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D59224

llvm-svn: 356616
2019-03-20 21:18:14 +00:00
Louis Dionne 77bca6d296 [NFC] Fix a couple of typos in libc++'s __config
llvm-svn: 356574
2019-03-20 17:05:52 +00:00
Louis Dionne b38c08ac02 [libc++] Mark <filesystem> tests as failing when the dylib doesn't support filesystem
This fixes CI for back-deployment testers on platforms that don't have
<filesystem> support in the dylib.

This is effectively half of https://reviews.llvm.org/D59224. The other
half requires fixes in Clang.

llvm-svn: 356558
2019-03-20 14:34:00 +00:00
Eric Fiselier 61b302f94f Remove exception throwing debug mode handler support.
Summary:
The reason libc++ implemented a throwing debug mode handler was for ease of testing. Specifically,
I thought that if a debug violation aborted, we could only test one violation per file. This made
it impossible to test debug mode. Which throwing behavior we could test more!

However, the throwing approach didn't work either, since there are debug violations underneath noexcept
functions. This lead to the introduction of `_NOEXCEPT_DEBUG`, which was only noexcept when debug
mode was off.

Having thought more and having grown wiser, `_NOEXCEPT_DEBUG` was a horrible decision. It was
viral, it didn't cover all the cases it needed to, and it was observable to the user -- at worst
changing the behavior of their program.

  This patch removes the throwing debug handler, and rewrites the debug tests using 'fork-ing' style
  death tests.

Reviewers: mclow.lists, ldionne, thomasanderson

Reviewed By: ldionne

Subscribers: christof, arphaman, libcxx-commits, #libc

Differential Revision: https://reviews.llvm.org/D59166

llvm-svn: 356417
2019-03-18 21:50:12 +00:00
Louis Dionne a470a13a70 [libc++] Enable deprecation warnings by default
Summary:
In r342843, I added deprecation warnings to some facilities that were
deprectated in C++14 and C++17. However, those deprecation warnings
were not enabled by default.

After discussing this on IRC, we had finally gotten consensus to enable
those warnings by default, and I'm getting around to doing that only
now.

Reviewers: mclow.lists, EricWF

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

Differential Revision: https://reviews.llvm.org/D58140

llvm-svn: 355961
2019-03-12 20:10:06 +00:00
Davide Italiano 6de760ac4e Reinstate libc++ patches now that the lldb formatter has been updated.
"[libc++] Fix <atomic> failures on GCC"
"[libc++] Change memory_order to an enum class"
"[libc++] decoupling Freestanding atomic<T> from libatomic.a"

llvm-svn: 355427
2019-03-05 18:40:49 +00:00
Davide Italiano 1061cb6a93 [libcxx] Revert set of atomic patches that broke lldb.
Revert "[libc++] Fix <atomic> failures on GCC"
Revert "[libc++] Change memory_order to an enum class"
Revert "[libc++] decoupling Freestanding atomic<T> from libatomic.a"

The lldb formatter nededs to be updated. Shafik and Louis will
coordinate to do so.

llvm-svn: 355417
2019-03-05 17:38:33 +00:00
Eric Fiselier e69290dc7f Make VCRuntime ABI configuration a first-class option.
Summary:
On Windows we currently provide two separate ABI configurations. One which defers to `vcruntime` to provide the C++ runtime and another which doesn't.
Using `vcruntime` allows interoperability which programs compiled against the MSVC STL, and should be preferred whenever possible.

When deferring to `vcruntime` much of the ABI we provide changes. Including the layout of `<stdexcept>` types, their vtables, and how the linkage of their members.

This patch introduces the `_LIBCPP_ABI_VCRUNTIME` macro to denote this configuration. It also cleans up the existing configuration for using `vcruntime`.

This cleanup lays the groundwork for fixing a number of ABI and interoperability bugs in  `<stdexcept>`.


Reviewers: thomasanderson, ldionne, smeenai

Reviewed By: smeenai

Subscribers: jdoerfert, libcxx-commits, #libc

Differential Revision: https://reviews.llvm.org/D58942

llvm-svn: 355366
2019-03-05 01:57:01 +00:00
Louis Dionne 21450545d1 [libc++] decoupling Freestanding atomic<T> from libatomic.a
This patch introduces non-lockfree atomics that do not require using
an external libatomic. This work is done with the long-term goal of
allowing the use of <atomic> in freestanding environments.

Thanks to Olivier Giroux for the patch.
Differential Revision: https://reviews.llvm.org/D56913

llvm-svn: 355318
2019-03-04 15:26:27 +00:00
Louis Dionne 5d79eaa82f [libc++] Rename _NOALIAS macro to _LIBCPP_NOALIAS
Summary:
For consistency, libc++ macros always start with _LIBCPP. This should
have no functionality change.

Reviewers: EricWF, mclow.lists

Subscribers: christof, jkorous, dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D58558

llvm-svn: 354848
2019-02-26 06:34:42 +00:00
Thomas Anderson 13447450bc [libc++] Don't define operator new/delete when using vcruntime
Fixes build errors on Windows without libc++abi of the form:

    new(173,36):  error: redeclaration of 'operator delete' cannot add 'dllexport' attribute
    _LIBCPP_OVERRIDABLE_FUNC_VIS void  operator delete(void* __p) _NOEXCEPT;
    vcruntime_new.h(87,16):  note: previous declaration is here
    void __CRTDECL operator delete(
    new(205,70):  error: redefinition of 'operator new'
    _LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new  (std::size_t, void* __p) _NOEXCEPT {return __p;}
    vcruntime_new.h(184,28):  note: previous definition is here
        inline void* __CRTDECL operator new(size_t _Size, _Writable_bytes_(_Size) void* _Where) noexcept
    new(206,70):  error: redefinition of 'operator new[]'
    _LIBCPP_NODISCARD_AFTER_CXX17 inline _LIBCPP_INLINE_VISIBILITY void* operator new[](std::size_t, void* __p) _NOEXCEPT {return __p;}
    vcruntime_new.h(199,28):  note: previous definition is here
        inline void* __CRTDECL operator new[](size_t _Size,
    new(207,40):  error: redefinition of 'operator delete'
    inline _LIBCPP_INLINE_VISIBILITY void  operator delete  (void*, void*) _NOEXCEPT {}
    vcruntime_new.h(190,27):  note: previous definition is here
        inline void __CRTDECL operator delete(void*, void*) noexcept
    new(208,40):  error: redefinition of 'operator delete[]'
    inline _LIBCPP_INLINE_VISIBILITY void  operator delete[](void*, void*) _NOEXCEPT {}
    vcruntime_new.h(206,27):  note: previous definition is here
        inline void __CRTDECL operator delete[](void*, void*) noexcept

Differential Revision: https://reviews.llvm.org/D57362

llvm-svn: 352647
2019-01-30 19:08:32 +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
Hans Wennborg 1fe469ae6c Bump the trunk version to 9.0.0svn
llvm-svn: 351320
2019-01-16 10:57:02 +00:00
Eric Fiselier d108bf85b0 Move internal usages of `alignof`/`__alignof` to use `_LIBCPP_ALIGNOF`.
Summary:
Starting in Clang 8.0 and GCC 8.0, `alignof` and `__alignof` return different values in same cases. Specifically `alignof` and `_Alignof` return the minimum alignment for a type, where as `__alignof` returns the preferred alignment. libc++ currently uses `__alignof` but means to use `alignof`. See  llvm.org/PR39713

This patch introduces the macro `_LIBCPP_ALIGNOF` so we can control which spelling gets used.

This patch does not introduce any ABI guard to provide the old behavior with newer compilers. However, if we decide that is needed, this patch makes it trivial to implement.

I think we should commit this change immediately, and decide what we want to do about the ABI afterwards. 

Reviewers: ldionne, EricWF

Reviewed By: ldionne, EricWF

Subscribers: jyknight, christof, libcxx-commits

Differential Revision: https://reviews.llvm.org/D54814

llvm-svn: 351289
2019-01-16 01:51:12 +00:00
Petr Hosek 2fefe153dd [libcxx] Mark do_open, do_get and do_close parameters unused when catopen is missing
When catopen is missing, do_open, do_get and do_close end up being
no-op, and as such their parameters will be unused which triggers a
warning/error when building with -Wunused-parameter.

Differential Revision: https://reviews.llvm.org/D56023

llvm-svn: 351027
2019-01-13 22:15:37 +00:00
Louis Dionne c8ca4d8cc1 [libcxx][NFC] Properly indent nested #ifdefs and #defines
I just realized I had always been reading this wrong because of the lack
of indentation, so I'm re-indenting this properly.

llvm-svn: 349408
2018-12-17 22:22:44 +00:00
Thomas Anderson 1cffc38485 [libc++] Fix _LIBCPP_EXPORTED_FROM_ABI when visibility annotations are disabled
Fixes a bug where functions would get exported when building with
-fvisibility=hidden and defining _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS. No
visibility annotations should be added in this case.

The new logic for _LIBCPP_EXPORTED_FROM_ABI matches that of the other visibility
annotations around it.

Differential Revision: https://reviews.llvm.org/D55664

llvm-svn: 349080
2018-12-13 20:06:14 +00:00
Marshall Clow 7dad0bd68b Second part of P0482 - char8_t. Reviewed as https://reviews.llvm.org/D55308
llvm-svn: 348828
2018-12-11 04:35:44 +00:00
Eric Fiselier 08e231dd9c Add a version of std::function that includes a few optimizations in ABI V2.
Patch by Jordan Soyke (jsoyke@google.com)
Reviewed as D55045

The result of running the benchmarks and comparing them can be found
here: https://gist.github.com/EricWF/a77fd42ec87fc98da8039e26d0349498

llvm-svn: 348812
2018-12-11 00:14:34 +00:00
Louis Dionne f7f5a1f778 [libcxx] Don't depend on availability markup to provide the streams in the dylib
Whether an explicit instantiation declaration should be provided is not
a matter of availability markup.

This problem is exemplified by the fact that some tests were incorrectly
marked as XFAIL when they should instead have been using the definition
of streams from the headers, and hence passing, and that, regardless of
whether visibility annotations are enabled.

llvm-svn: 348436
2018-12-06 00:24:58 +00:00
Louis Dionne e823b6d7e6 [libcxx] Remove bad_array_length
Summary:
std::bad_array_length was added by n3467, but this never made it into C++.
This commit removes the definition of std::bad_array_length from the headers
AND from the shared library. See the comments in the ABI changelog for details
about the ABI implications of this change.

Reviewers: mclow.lists, dexonsmith, howard.hinnant, EricWF

Subscribers: christof, jkorous, libcxx-commits

Differential Revision: https://reviews.llvm.org/D54804

llvm-svn: 347903
2018-11-29 19:44:57 +00:00
Eric Fiselier 9d25ada420 Revert "Move internal usages of `alignof`/`__alignof` to use `_LIBCPP_ALIGNOF`. "
This reverts commit 087f065cb0c7463f521a62599884493aaee2ea12.

The tests were failing on 32 bit builds, and I don't have time
to clean them up right now. I'll recommit tomorrow with fixed tests.

llvm-svn: 347816
2018-11-28 22:24:19 +00:00
Eric Fiselier 8a486dac25 Move internal usages of `alignof`/`__alignof` to use `_LIBCPP_ALIGNOF`.
Summary:
Starting in Clang 8.0 and GCC 8.0, `alignof` and `__alignof` return different values in same cases. Specifically `alignof` and `_Alignof` return the minimum alignment for a type, where as `__alignof` returns the preferred alignment. libc++ currently uses `__alignof` but means to use `alignof`. See  llvm.org/PR39713

This patch introduces the macro `_LIBCPP_ALIGNOF` so we can control which spelling gets used.

This patch does not introduce any ABI guard to provide the old behavior with newer compilers. However, if we decide that is needed, this patch makes it trivial to implement.

I think we should commit this change immediately, and decide what we want to do about the ABI afterwards. 

Reviewers: ldionne, EricWF

Reviewed By: EricWF

Subscribers: christof, libcxx-commits

Differential Revision: https://reviews.llvm.org/D54814

llvm-svn: 347787
2018-11-28 18:16:02 +00:00
Louis Dionne 9a494eacba [libcxx] Remove dynarray
Summary:
std::dynarray had been proposed for C++14, but it was pulled out from C++14
and there are no plans to standardize it anymore.

Reviewers: mclow.lists, EricWF

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

Differential Revision: https://reviews.llvm.org/D54801

llvm-svn: 347783
2018-11-28 18:02:00 +00:00
Louis Dionne 2804508ffe [libcxx] Remove unused definition of aligned allocation macro on old OS X
We don't support mac OS 10.6 and older anymore, so this macro can never
be defined. This bit of code had been added in D28931 as a fix for
PR31448, but it doesn't seem necessary anymore.

llvm-svn: 347427
2018-11-21 21:22:08 +00:00
Louis Dionne 8eb65cb25e [NFC] Reformat availability #defines in __config
Aligning everything makes what we're doing more obvious.

llvm-svn: 347363
2018-11-20 23:18:25 +00:00
Louis Dionne c2b375ad60 [libcxx] Fix threads detection on GNU/Hurd
GNU/Hurd provides standard Posix threads

Reviewed as https://reviews.llvm.org/D54339.
Thanks to Samuel Thibault for the patch.

llvm-svn: 347347
2018-11-20 21:14:05 +00:00
Louis Dionne 8a063df194 [libcxx] Add availability markup for bad_optional_access, bad_variant_access and bad_any_cast
Reviewers: dexonsmith, EricWF

Subscribers: christof, arphaman, libcxx-commits

Differential Revision: https://reviews.llvm.org/D53256

llvm-svn: 347219
2018-11-19 15:37:04 +00:00
Reid Kleckner 60cce5c782 Use C++11 fallthrough attribute syntax when available and add a break
Summary:
This silences the two -Wimplicit-fallthrough warnings clang finds in
ItaniumDemangle.h in libc++abi.

Clang does not have a GNU attribute spelling for this attribute, so this
is necessary.

I will commit the same change to the LLVM demangler soon.

Reviewers: EricWF, ldionne

Subscribers: christof, erik.pilkington, cfe-commits

Differential Revision: https://reviews.llvm.org/D53985

llvm-svn: 345870
2018-11-01 18:24:03 +00:00
Eric Fiselier fe13c13cc2 Make libc++'s versioning namespace customizable
Summary:
This patch makes the versioning namespace libc++ uses customizable by the user using `-DLIBCXX_ABI_NAMESPACE=__foo`. 

This allows users to build custom versions of libc++ which can be linked into binaries with other libc++ versions without causing symbol conflicts or ODR issues. 

Reviewers: mclow.lists, ldionne

Reviewed By: ldionne

Subscribers: kristina, smeenai, mgorny, phosek, libcxx-commits

Differential Revision: https://reviews.llvm.org/D53879

llvm-svn: 345657
2018-10-30 21:44:53 +00:00
Eric Fiselier 2f3e8b3d2e Unify definition of _LIBCPP_BEGIN/END_NAMESPACE_STD
llvm-svn: 345561
2018-10-30 02:02:00 +00:00
Louis Dionne e9d85264ac [libc++] Use exclude_from_explicit_instantiation instead of always_inline
Summary:
This commit adopts the exclude_from_explicit_instantiation attribute discussed
at [1] and reviewed in [2] in libc++ to supplant the use of __always_inline__
for visibility purposes.

This change means that users wanting to link together translation units built
with different versions of libc++'s headers into the same final linked image
MUST define the _LIBCPP_HIDE_FROM_ABI_PER_TU macro to 1 when building those
TUs. Doing otherwise will lead to ODR violations and ABI issues.

[1]: http://lists.llvm.org/pipermail/cfe-dev/2018-August/059024.html
[2]: https://reviews.llvm.org/D51789

Reviewers: rsmith, EricWF

Subscribers: dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D52405

llvm-svn: 345516
2018-10-29 17:30:04 +00:00
Louis Dionne 9b3222f613 [libc++] Make sure we can build libc++ with -fvisibility=hidden
Summary:
When building with -fvisibility=hidden, some symbols do not get exported from
libc++.dylib. This means that some entities are not explicitly given default
visibility in the source code, and that we rely on the fact -fvisibility=default
is the default. This commit explicitly gives default visibility to those
symbols to avoid being dependent on the command line flags used.

The commit also remove symbols from the dylib -- those symbols do not
actually need to be exported from the dylib and this should not be an
ABI break.

Finally, in the future, we may want to mark the whole std:: namespace as
having hidden visibility (to switch from opt-out to opt-in), in which
case the changes done in this commit will be required.

Reviewers: EricWF

Subscribers: mgorny, christof, dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D52662

llvm-svn: 345260
2018-10-25 12:13:43 +00:00
Louis Dionne 4084df0040 [libcxx] Avoid repeating the definition of std:: namespaces
This reduces code duplication a tiny bit.

llvm-svn: 344642
2018-10-16 20:02:59 +00:00
Louis Dionne 7833b88ad8 [libcxx] Remove _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
That macro has been defined to _LIBCPP_HIDE_FROM_ABI_AFTER_V1 for many
weeks now, so we're actually replacing uses of it for uses of
_LIBCPP_HIDE_FROM_ABI_AFTER_V1 directly.

This should not change or break anything since the two macros are
100% equivalent, unless somebody is (incorrectly!) relying on
_LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY being defined.

llvm-svn: 344641
2018-10-16 19:26:23 +00:00
Marshall Clow 5b08c1742a Recommit <chrono> changes with a couple xtra tests marked to fail on apple's clang. Reviewed as D51762
llvm-svn: 344627
2018-10-16 17:27:54 +00:00
Artem Dergachev a9bc0face5 Revert r344529 "Implement the first part of the calendar support for C++20"
Revert r344535 "Wrap up the new chrono literals in an #ifdef..."
Revert r344546 "Mark a couple of test cases as 'C++17-only'..."

Some of the buildbot failures were masked by another error,
and this one was probably missed.

llvm-svn: 344580
2018-10-16 02:40:42 +00:00
Marshall Clow 323e01d46f Wrap up the new chrono literals in an #ifdef so that old versions of clang don't complain. I'm looking at you, clang 5.0.1
llvm-svn: 344535
2018-10-15 17:33:20 +00:00
Eric Fiselier 42f9868cd8 Distinguish between library and language support for aligned allocation.
There are two cases:
1. The library has all it needs to provide align_val_t and the
new/delete overloads needed to support aligned allocation.
2. The compiler has actually turned the language feature on.

There are times where libc++ needs to distinguish between the two.

This patch adds the additional macro
_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION which denotes when case (1)
does not hold. _LIBCPP_HAS_NO_ALIGNED_ALLOCATION is defined whenever
_LIBCPP_HAS_NO_LIBRARY_ALIGNED_ALLOCATION is defined, or when the
compiler has not enabled the language feature.

Additionally this patch cleans up a number of other macros related
to detection of aligned allocation machinery.

llvm-svn: 344207
2018-10-11 00:17:24 +00:00
Louis Dionne f9a52903ef [libc++] Remove Fuchsia-specific knowledge to pick the ABI version
Summary:
The ABI version used by libc++ is a configuration option just like any other
configuration option. It is a knob that can be used by vendors to customize
the libc++ that they ship. As such, we should not be hardcoding vendor-specific
configuration choices in libc++.

When building libc++ for Fuchsia, Fuchsia's build scripts should simply define
the libc++ ABI version to 2 -- this will result in the _LIBCPP_ABI_VERSION
macro being defined in the __config header that is generated when libc++ is
built and installed, which is the correct way to customize libc++'s behavior
for specific vendors.

Reviewers: phosek, EricWF

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

Differential Revision: https://reviews.llvm.org/D52397

llvm-svn: 343079
2018-09-26 08:24:51 +00:00
Louis Dionne ea5cd3b476 [libc++] Add deprecated attributes to many deprecated components
Summary:
These deprecation warnings are opt-in: they are only enabled when the
_LIBCXX_DEPRECATION_WARNINGS macro is defined, which is not the case
by default. Note that this is a first step in the right direction, but
I wasn't able to get an exhaustive list of all deprecated components
per standard, so there's certainly stuff that's missing. The list of
components this commit marks as deprecated is:

in C++11:
- auto_ptr, auto_ptr_ref
- binder1st, binder2nd, bind1st(), bind2nd()
- pointer_to_unary_function, pointer_to_binary_function, ptr_fun()
- mem_fun_t, mem_fun1_t, const_mem_fun_t, const_mem_fun1_t, mem_fun()
- mem_fun_ref_t, mem_fun1_ref_t, const_mem_fun_ref_t, const_mem_fun1_ref_t, mem_fun_ref()

in C++14:
- random_shuffle()

in C++17:
- unary_negate, binary_negate, not1(), not2()

<rdar://problem/18168350>

Reviewers: mclow.lists, EricWF

Subscribers: christof, dexonsmith, llvm-commits

Differential Revision: https://reviews.llvm.org/D48912

llvm-svn: 342843
2018-09-23 18:35:00 +00:00
Roman Lebedev c65d39a464 [libc++] Add _LIBCPP_ENABLE_NODISCARD and _LIBCPP_NODISCARD_EXT to allow pre-C++2a [[nodiscard]]
Summary:
The `[[nodiscard]]` attribute is intended to help users find bugs where
function return values are ignored when they shouldn't be. After C++17 the
C++ standard has started to declared such library functions as `[[nodiscard]]`.
However, this application is limited and applies only to dialects after C++17.
Users who want help diagnosing misuses of STL functions may desire a more
liberal application of `[[nodiscard]]`.

For this reason libc++ provides an extension that does just that! The
extension must be enabled by defining `_LIBCPP_ENABLE_NODISCARD`. The extended
applications of `[[nodiscard]]` takes two forms:

1. Backporting `[[nodiscard]]` to entities declared as such by the
   standard in newer dialects, but not in the present one.

2. Extended applications of `[[nodiscard]]`, at the libraries discretion,
   applied to entities never declared as such by the standard.

Users may also opt-out of additional applications `[[nodiscard]]` using
additional macros.

Applications of the first form, which backport `[[nodiscard]]` from a newer
dialect may be disabled using macros specific to the dialect it was added. For
example `_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17`.

Applications of the second form, which are pure extensions, may be disabled
by defining `_LIBCPP_DISABLE_NODISCARD_EXT`.

This patch was originally written by me (Roman Lebedev),
then but then reworked by Eric Fiselier.

Reviewers: mclow.lists, thakis, EricWF

Reviewed By: thakis, EricWF

Subscribers: llvm-commits, mclow.lists, lebedev.ri, EricWF, rjmccall, Quuxplusone, cfe-commits, christof

Differential Revision: https://reviews.llvm.org/D45179

llvm-svn: 342808
2018-09-22 17:54:48 +00:00
Louis Dionne 61cd687009 [libcxx] By default, do not use internal_linkage to hide symbols from the ABI
Summary:
https://reviews.llvm.org/D49240 led to symbol size problems in Chromium, and
we expect this may be the case in other projects built in debug mode too.
Instead, unless users explicitly ask for internal_linkage, we use always_inline
like we used to.

In the future, when we have a solution that allows us to drop always_inline
without falling back on internal_linkage, we can replace always_inline by
that.

Note that this commit introduces a change in contract for existing libc++
users: by default, libc++ used to guarantee that TUs built with different
versions of libc++ could be linked together. With the introduction of the
_LIBCPP_HIDE_FROM_ABI_PER_TU macro, the default behavior is that TUs built
with different libc++ versions are not guaranteed to link. This is a change
in contract but not a change in behavior, since the current implementation
still allows linking TUs built with different libc++ versions together.

Reviewers: EricWF, mclow.lists, dexonsmith, hans, rnk

Subscribers: christof, cfe-commits

Differential Revision: https://reviews.llvm.org/D50652

llvm-svn: 339874
2018-08-16 12:44:28 +00:00
Marshall Clow 171c77b7da Selectively import timespec_get into namespace std, since some C libraries don't have it. Reviewed as https://reviews.llvm.org/D50799
llvm-svn: 339816
2018-08-15 21:19:08 +00:00
Louis Dionne 894ffdd82f [libc++] Detect C11 features on non-Clang compilers
Summary:
The macros were inside `#if defined(_LIBCPP_COMPILER_CLANG)`, which means
we would never detect C11 features on non-Clang compilers. According to
Marshall Clow, this is not the intended behavior.

Reviewers: mclow.lists, EricWF

Subscribers: krytarowski, christof, dexonsmith, cfe-commits

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

llvm-svn: 339741
2018-08-15 00:16:41 +00:00