Commit Graph

79 Commits

Author SHA1 Message Date
Louis Dionne
9783f28cbb [libc++] Format the code base (#74334)
This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.

This patch was generated with:

   find libcxx/include libcxx/src -type f \
      | grep -v 'module.modulemap.in' \
      | grep -v 'CMakeLists.txt' \
      | grep -v 'README.txt' \
      | grep -v 'libcxx.imp' \
      | grep -v '__config_site.in' \
      | xargs clang-format -i

A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.

[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
2023-12-18 14:01:33 -05:00
Louis Dionne
77a00c0d54 [libc++] Replace uses of _VSTD:: by std:: (#74331)
As part of the upcoming clang-formatting of libc++, this patch performs
the long desired removal of the _VSTD macro.

See https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
for the clang-format proposal.
2023-12-05 11:19:15 -05:00
Louis Dionne
4c19854222 [libc++] Rename _LIBCPP_INLINE_VISIBILITY to _LIBCPP_HIDE_FROM_ABI (#74095)
In preparation for running clang-format on the whole code base, we are
also removing mentions of the legacy _LIBCPP_INLINE_VISIBILITY macro in
favor of the newer _LIBCPP_HIDE_FROM_ABI.

We're still leaving the definition of _LIBCPP_INLINE_VISIBILITY to avoid
creating needless breakage in case some older patches are checked-in
with mentions of the old macro. After we branch for LLVM 18, we can do
another pass to clean up remaining uses of the macro that might have
gotten introduced by mistake (if any) and remove the macro itself at the
same time. This is just a minor convenience to smooth out the transition
as much as possible.

See
https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
for the clang-format proposal.
2023-12-04 10:25:14 -05:00
philnik777
ec350ad418 [libc++] Remove availability annotations which can never be triggered (#69226)
According to https://developer.apple.com/support/xcode/, quite a few of
our availability macros don't do anything anymore, so we might as well
remove them to clean up the code a bit.
2023-11-01 23:56:43 +01:00
philnik777
a65070a76a [libc++] Remove a few transitive includes (#70553) 2023-10-29 18:31:37 +01:00
Ilya Biryukov
f722db02d3 [libc++] Use correct size for deallocation of arrays in shared_ptr (#68233)
Fixes #68051.

Current implementation passes the number of `_AlignedStorage` objects
when it calls to `allocate` and the number of **bytes** on `deallocate`.
This only applies to allocations that allocate control block and the
storage together, i.e. `make_shared` and `allocate_shared`.

Found by ASan under Clang combined with `-fsized-deallocation`.
2023-10-05 15:27:58 +02:00
Amirreza Ashouri
b861457c90 [libc++] Fix a segfault in weak_ptr(const weak_ptr<Y>&) (#67956)
Fixes https://github.com/llvm/llvm-project/issues/40459
2023-10-02 17:52:34 -04:00
Louis Dionne
85f27d126d [libc++] Make sure LWG2070 is implemented as a DR (#65998)
When we implemented C++20's P0674R1, we didn't enable the part of
P0674R1 that was resolving LWG2070 as a DR. This patch fixes that and
makes sure that we consistently go through the allocator when
constructing and destroying the underlying object in
std::allocate_shared.

Fixes #54365.
2023-09-14 15:12:06 -04:00
Igor Zhukov
70248920fc [libc++][test] Add '-Wdeprecated-copy', '-Wdeprecated-copy-dtor' warnings to the test suite
This is a follow up to https://reviews.llvm.org/D144694.
Fixes https://github.com/llvm/llvm-project/issues/60977.

Differential Revision: https://reviews.llvm.org/D144775
2023-09-12 08:53:38 -04:00
Nikolas Klauser
4da76ea70a [libc++][NFC] Refactor enable_ifs in defaulted arguments to defaulted template arguments
This brings most of the enable_ifs in libc++ to the same style. It also has the nice side-effect of reducing the size of names of these symbols, since the arguments don't get mangled anymore.

Reviewed By: #libc, Mordante

Spies: Mordante, libcxx-commits

Differential Revision: https://reviews.llvm.org/D157748
2023-08-18 13:08:18 -07:00
Nikolas Klauser
475bd19ee8 [libc++][NFC] Refactor return type enable_ifs to defaulted template arguments
This brings most of the enable_ifs in libc++ to the same style. It also has the nice side-effect of reducing the size of names of these symbols, since the depedent return type is shorter.

Reviewed By: #libc, ldionne

Spies: ldionne, libcxx-commits

Differential Revision: https://reviews.llvm.org/D157736
2023-08-15 12:19:21 -07:00
pateldeev
347f45ed2b [libc++][LWG 2996] Implement c++20 shared_ptr rvalue overloads.
Implement c++20 `shared_ptr` rvalue overloads for aliasing constructor and pointer casts. See https://cplusplus.github.io/LWG/issue2996

Commit from
"patedeev" <dkp10000@gmail.com>

Reviewed By: philnik, #libc, ldionne, pateldeev

Differential Revision: https://reviews.llvm.org/D135548
2023-07-18 20:04:21 +02:00
Nikolas Klauser
f1ea0b11ca [libc++] Merge _LIBCPP_FUNC_VIS, _LIBCPP_TYPE_VIS and _LIBCPP_EXCEPTION_ABI into _LIBCPP_EXPORTED_FROM_ABI
These macros are always defined identically, so we can simplify the code a bit by merging them.

Reviewed By: ldionne, #libc

Spies: libcxx-commits, krytarowski, smeenai

Differential Revision: https://reviews.llvm.org/D152652
2023-06-15 08:56:45 -07:00
Nikolas Klauser
83ce139721 [libc++] Add hide_from_abi check for classes
We already have a clang-tidy check for making sure that `_LIBCPP_HIDE_FROM_ABI` is on free functions. This patch extends this to class members. The places where we don't check for `_LIBCPP_HIDE_FROM_ABI` are classes for which we have an instantiation in the library.

Reviewed By: ldionne, Mordante, #libc

Spies: jplehr, mikhail.ramalho, sstefan1, libcxx-commits, krytarowski, miyuki, smeenai

Differential Revision: https://reviews.llvm.org/D142332
2023-04-16 15:23:23 +02:00
Nikolas Klauser
75196f8e72 [libc++] Remove <cstdlib> includes
We changed the `abort` calls when trying to throw exceptions in `-fno-exceptions` mode to `__verbose_abort` calls, which removes the dependency in most files.

Reviewed By: ldionne, #libc

Spies: dim, emaste, mikhail.ramalho, smeenai, libcxx-commits

Differential Revision: https://reviews.llvm.org/D146076
2023-04-09 02:52:33 +02:00
Nikolas Klauser
308bcb3f7b [libc++] Use the _LIBCPP_VERBOSE_ABORT macro instead of calling the function directly
These calls were added in D141222.

Reviewed By: #libc, ldionne

Spies: ldionne, libcxx-commits, smeenai, mikhail.ramalho

Differential Revision: https://reviews.llvm.org/D146227
2023-03-18 00:34:28 +01:00
Nikolas Klauser
16d1b0e105 [libc++] Use __verbose_abort instead of std::abort in __throw_ functions
This results in proper error messages instead of just an abort.

Reviewed By: ldionne, Mordante, #libc

Spies: #libc_vendors, smeenai, libcxx-commits

Differential Revision: https://reviews.llvm.org/D141222
2023-03-14 19:33:19 +01:00
Nikolas Klauser
43562287a8 [libc++] Granularize <exception>
This patch also updates the moved code to the new style (i.e. formatted, replaced marcos and typedefs)

Reviewed By: ldionne, #libc

Spies: arichardson, libcxx-commits

Differential Revision: https://reviews.llvm.org/D145095
2023-03-12 22:19:41 +01:00
Nikolas Klauser
70617a1a23 [libc++] Granularize <atomic> includes
Reviewed By: ldionne, Mordante, #libc

Spies: arichardson, libcxx-commits

Differential Revision: https://reviews.llvm.org/D144255
2023-03-10 13:28:29 +01:00
Nikolas Klauser
0a4aa8a122 [libc++] Granularize <type_traits> includes
Reviewed By: ldionne, #libc, #libc_abi

Spies: #libc_vendors, smeenai, libcxx-commits

Differential Revision: https://reviews.llvm.org/D145320
2023-03-08 22:05:04 +01:00
Nikolas Klauser
e65cd4ce83 [libc++] Enable -Wunused-template
Clang wants to enable this flag by default, but libc++ isn't working with it yet.

Reviewed By: Mordante, #libc, #libc_abi, EricWF

Spies: libcxx-commits, arichardson

Differential Revision: https://reviews.llvm.org/D144667
2023-03-08 19:26:49 +01:00
Nikolas Klauser
b22aa3d74f [libc++][NFC] Rename _LIBCPP_NO_EXCEPTIONS to _LIBCPP_HAS_NO_EXCEPTIONS
Other macros that disable parts of the library are named `_LIBCPP_HAS_NO_WHATEVER`.

Reviewed By: ldionne, Mordante, #libc

Spies: libcxx-commits, smeenai

Differential Revision: https://reviews.llvm.org/D143163
2023-02-17 17:39:03 +01:00
Nikolas Klauser
4f15267d3d [libc++][NFC] Replace _LIBCPP_STD_VER > x with _LIBCPP_STD_VER >= x
This change is almost fully mechanical. The only interesting change is in `generate_feature_test_macro_components.py` to generate `_LIBCPP_STD_VER >=` instead. To avoid churn in the git-blame this commit should be added to the `.git-blame-ignore-revs` once committed.

Reviewed By: ldionne, var-const, #libc

Spies: jloser, libcxx-commits, arichardson, arphaman, wenlei

Differential Revision: https://reviews.llvm.org/D143962
2023-02-15 16:52:25 +01:00
Louis Dionne
5801090258 [libc++] Fix bug in allocate_shared_for_overwrite
Instead of destroying the object with allocator::destroy, we must
call its destructor directly. As a fly-by also mark LWG3008 as
fixed since it is handled by our implementation.

This was pointed out by Tim Song in https://reviews.llvm.org/D140913.

Differential Revision: https://reviews.llvm.org/D143791
2023-02-13 08:50:54 -05:00
Hui
a38a4654ce [libc++] fix shared_ptr's incorrect constraints
Fix several bugs:
1. https://llvm.org/PR60258
   The conversion constructors' constraint `__compatible_with` incorrectly allow array types conversion to scalar types
2. https://llvm.org/PR53368
   The constructor that takes `unique_ptr` are not suffiently constrained.
3. The constructors that take raw pointers incorretly use `__compatible_with`. They have different constraints

Differential Revision: https://reviews.llvm.org/D143346
2023-02-11 19:44:38 +00:00
Nikolas Klauser
cf65d275ac [libc++][NFC] Rename _LIBCPP_NO_RTTI to _LIBCPP_HAS_NO_RTTI
Other macros that disable parts of the library are named `_LIBCPP_HAS_NO_WHATEVER`.

Reviewed By: ldionne, Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D143164
2023-02-05 00:21:56 +01:00
Nikolas Klauser
c8eff9560f [libc++] Add a clang-tidy check to make sure we use _Uglyfied attribute names
Reviewed By: ldionne, #libc

Spies: krytarowski, jdoerfert, libcxx-commits

Differential Revision: https://reviews.llvm.org/D142322
2023-02-01 18:57:06 +01:00
Nikolas Klauser
ba43f3e857 [libc++][NFC] Rename multidimentional uninitialized algorithms
Reviewed By: Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D142526
2023-01-26 09:58:29 +01:00
Hui
9af9d39a47 [libc++] implement P1020R1 P1973R1 make_unique[shared]_for_overwrite
Differential Revision: https://reviews.llvm.org/D140913
2023-01-23 21:07:22 +00:00
Nikolas Klauser
73e8e1ba8d [libc++][NFC] Qualify declval
While it's not necessary to qualify calls to `declval` it makes error messages very crypric if the declaration isn't reachable anymore

For example:
```
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:53:66: error: no type named 'type' in 'std::common_type<long, long>'
        typedef chrono::duration<typename common_type<_Rep1, _Rep2>::type,
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_type.h:107:14: note: in instantiation of template class 'std::common_type<std::chrono::duration<long, std::ratio<3600, 1>>, std::chrono::duration<long, std::ratio<3600, 1>>>' requested here
        : public common_type<_Tp, _Tp> {};
                 ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:279:58: note: in instantiation of template class 'std::common_type<std::chrono::duration<long, std::ratio<3600, 1>>>' requested here
        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator+() const {return typename common_type<duration>::type(*this);}
                                                             ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:308:54: note: in instantiation of template class 'std::chrono::duration<long, std::ratio<3600, 1>>' requested here
    typedef duration<     int, ratio_multiply<ratio<24>, hours::period>>         days;
                                                         ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:280:81: error: no type named 'type' in 'std::common_type<std::chrono::duration<long, std::ratio<3600, 1>>>'
        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator-() const {return typename common_type<duration>::type(-__rep_);}
                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:308:54: note: in instantiation of template class 'std::chrono::duration<long, std::ratio<3600, 1>>' requested here
    typedef duration<     int, ratio_multiply<ratio<24>, hours::period>>         days;
                                                         ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:53:66: error: no type named 'type' in 'std::common_type<int, int>'
        typedef chrono::duration<typename common_type<_Rep1, _Rep2>::type,
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_type.h:107:14: note: in instantiation of template class 'std::common_type<std::chrono::duration<int, std::ratio<86400, 1>>, std::chrono::duration<int, std::ratio<86400, 1>>>' requested here
        : public common_type<_Tp, _Tp> {};
                 ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:279:58: note: in instantiation of template class 'std::common_type<std::chrono::duration<int, std::ratio<86400, 1>>>' requested here
        _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR typename common_type<duration>::type operator+() const {return typename common_type<duration>::type(*this);}
                                                             ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__chrono/duration.h:309:55: note: in instantiation of template class 'std::chrono::duration<int, std::ratio<86400, 1>>' requested here
    typedef duration<     int, ratio_multiply<ratio<7>,   days::period>>         weeks;
                                                          ^
    19 similar errors omitted
```
changes with qualification added to:
```
    While building module 'std' imported from /home/nikolask/llvm-projects/libcxx/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp:13:
    In file included from <module-includes>:17:
    In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/math.h:309:
    In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/limits:107:
    In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/type_traits:432:
    In file included from /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_reference.h:13:
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__type_traits/common_type.h:28:43: error: declaration of 'declval' must be imported from module 'std.utility.__utility.declval' before it is required
    using __cond_type = decltype(false ? std::declval<_Tp>() : std::declval<_Up>());
                                              ^
    /home/nikolask/llvm-projects/libcxx/build/include/c++/v1/__utility/declval.h:30:34: note: declaration here is not visible
    decltype(std::__declval<_Tp>(0)) declval() _NOEXCEPT;
                                     ^
    /home/nikolask/llvm-projects/libcxx/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp:13:10: fatal error: could not build module 'std'
    #include <functional>
     ~~~~~~~~^
    2 errors generated.
```

Reviewed By: ldionne, Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D130854
2023-01-12 18:28:41 +01:00
Louis Dionne
5efc81166d [libc++] Remove HIDE_FROM_ABI from virtual functions
_LIBCPP_HIDE_FROM_ABI (which is what _LIBCPP_INLINE_VISIBILITY is) uses
ABI tags to avoid ODR violations when linking together object files
compiled against different versions of libc++. However, pointer
authentication uses the mangled name of the function to sign the
function pointer in the vtable, which means that the ABI tag effectively
changes how the pointers are signed.

This leads to PAC failures when passing an object that holds one of these
pointers in its vtable across an ABI boundary: one side will sign the
pointer using one function mangling (with one ABI tag), and the other
side will authenticate the pointer expecting it to have a different
mangled name, which won't work.

To make sure this does not regress in the future, this patch also adds
a clang-query test to detect incorrect applications of _LIBCPP_HIDE_FROM_ABI.

Differential Revision: https://reviews.llvm.org/D140453
2023-01-09 10:29:42 -05:00
Nikolas Klauser
841399a218 [libc++] Add custom clang-tidy checks
Reviewed By: #libc, ldionne

Spies: jwakely, beanz, smeenai, cfe-commits, tschuett, avogelsgesang, Mordante, sstefan1, libcxx-commits, ldionne, mgorny, arichardson, miyuki

Differential Revision: https://reviews.llvm.org/D131963
2022-12-23 15:42:13 +01:00
Nikolas Klauser
e0a66116fc [libc++] Granularize <type_traits> includes in <compare>
Reviewed By: Mordante, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D140480
2022-12-23 02:58:06 +01:00
Nikolas Klauser
59ef4b3686 [libc++] Split __allocator_destructor out of shared_ptr.h
Reviewed By: ldionne, huixie90, #libc

Spies: libcxx-commits

Differential Revision: https://reviews.llvm.org/D134479
2022-11-05 21:25:54 +01:00
Nikolas Klauser
5fab33af7f [libc++] Avoid instantiating type_trait classes
Use `using` aliases to avoid instantiating lots of types

Reviewed By: ldionne, #libc

Spies: libcxx-commits, miyuki

Differential Revision: https://reviews.llvm.org/D132785
2022-09-06 19:09:42 +02:00
Nikolas Klauser
d5e26775d0 [libc++] Granularize the rest of memory
Reviewed By: ldionne, #libc

Spies: vitalybuka, paulkirth, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D132790
2022-09-05 12:36:41 +02:00
Vitaly Buka
bc8fd9c633 Revert "[libc++] Granularize the rest of memory"
Breaks buildbots.

This reverts commit 30adaa730c.
2022-09-02 19:42:49 -07:00
Nikolas Klauser
30adaa730c [libc++] Granularize the rest of memory
Reviewed By: ldionne, #libc

Spies: libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D132790
2022-09-02 21:42:41 +02:00
Nikolas Klauser
84fc2c3cd6 [libc++] Make the naming of private member variables consistent and enforce it through readability-identifier-naming
Reviewed By: ldionne, #libc

Spies: aheejin, sstefan1, libcxx-commits

Differential Revision: https://reviews.llvm.org/D129386
2022-09-02 21:36:36 +02:00
Nikolas Klauser
4262b523ff [libc++][NFC] Enable modernize-use-override
Reviewed By: Mordante, #libc

Spies: aheejin, libcxx-commits, smeenai

Differential Revision: https://reviews.llvm.org/D124714
2022-08-25 20:55:08 +02:00
Nikolas Klauser
80c7e93a2a [libc++] Add a bunch of missing _LIBCPP_HIDE_FROM_ABI
Reviewed By: ldionne, Mordante, var-const, huixie90, #libc

Spies: jloser, libcxx-commits, arichardson, miyuki

Differential Revision: https://reviews.llvm.org/D129968
2022-08-13 22:41:22 +02:00
Adrian Vogelsgesang
3b217f2f12 [libc++] Implement operator<=> for shared_ptr
Implements part of:

* P1614R2 The Mothership has Landed

Fixes LWG3427

Reviewed By: #libc, Mordante

Differential Revision: https://reviews.llvm.org/D130852
2022-08-03 18:32:45 +02:00
Nikolas Klauser
681cde7dd8 [libc++] Complete the implementation of N4190
Fixes #37402

Reviewed By: ldionne

Spies: EricWF, avogelsgesang, libcxx-commits, arphaman

Differential Revision: https://reviews.llvm.org/D124346
2022-06-22 10:13:03 +02:00
Nikolas Klauser
971e9c80e9 [libc++] Implement std::boyer_moore{, _horspool}_searcher
This mostly copys the `<experimental/functional>` stuff and updates the code to current libc++ style.

Reviewed By: ldionne, #libc

Spies: nlopes, adamdebreceni, arichardson, libcxx-commits, mgorny

Differential Revision: https://reviews.llvm.org/D121074
2022-06-17 19:09:40 +02:00
Louis Dionne
0cc34ca7ec [libc++] Define legacy symbols for inline functions at a finer-grained level
When we build the library with the stable ABI, we need to include some
functions in the dylib that were made inline in later versions of the
library (to avoid breaking code that might be relying on those symbols).

However, those methods were made non-inline whenever we'd be building
the library, which means that all translation units would end up using
the old out-of-line definition of these methods, as opposed to the new
inlined version. This patch makes it so that only the translation units
that actually define the out-of-line methods use the old definition,
opening up potential optimization opportunities in other translation
units.

This should solve some of the issues encountered in D65667.

Differential Revision: https://reviews.llvm.org/D123519
2022-04-12 13:44:30 -04:00
Louis Dionne
b9ca1e5a5a [libc++][NFC] Use noexcept instead of _NOEXCEPT for code compiled into the library
We build the library with C++20 anyways, so we can use noexcept directly.
2022-04-11 12:30:38 -04:00
Louis Dionne
e27a122b3a [libc++] Support arrays in make_shared and allocate_shared (P0674R1)
This patch implements P0674R1, i.e. support for arrays in std::make_shared
and std::allocate_shared.

Co-authored-by: Zoe Carver <z.zoelec2@gmail.com>

Differential Revision: https://reviews.llvm.org/D62641
2022-04-06 08:42:55 -04:00
Asher Mancinelli
34538dba9b [libc++] Make shared_ptr move unique_ptr's deleter
Addresses LWG 3548 which mandates that when shared_ptr is being constructed from a unique_ptr, the unique_ptr's deleter should be moved and not copied.

Reviewed By: #libc, philnik, EricWF

Differential Revision: https://reviews.llvm.org/D119159
2022-03-18 11:50:31 -06:00
Louis Dionne
a54d028895 Revert "[libc++] Remove extension to support allocator<const T>"
This reverts commit 276ca873. That commit has quite a history at this
point. It was first landed in dbc647643577, which broke std::shared_ptr<T const>
and was reverted in 9138666f5. It was then re-applied in 276ca873, with
the std::shared_ptr issue fixed, but it caused widespread breakage at
Google (which suggests it would cause similar breakage in the wild too),
so now I'm reverting again.

Instead, I will add a escape hatch that vendors can turn on to enable
the extension and perform a phased transition over one or two releases
like we sometimes do when things become non-trivial.
2022-03-09 17:04:18 -05:00
Louis Dionne
276ca87382 [libc++] Remove extension to support allocator<const T>
This extension is a portability trap for users, since no other standard
library supports it. Furthermore, the Standard explicitly allows
implementations to reject std::allocator<cv T>, so allowing it is
really going against the current.

This was discovered in D120684: this extension required `const_cast`ing
in `__construct_range_forward`, a fishy bit of code that can be removed
if we don't support the extension anymore.

This is a re-application of dbc647643577, which was reverted in 9138666f5
because it broke std::shared_ptr<T const>. Tests have now been added and
we've made sure that std::shared_ptr<T const> wouldn't be broken in this
version.

Differential Revision: https://reviews.llvm.org/D120996
2022-03-08 15:05:12 -05:00