Previously we implemented all one trillion tuple-like constructors using
a single generic overload. This worked fairly well, except that it
differed in behavior from the standard version because it didn't
consider both T&& and T const&. This was observable for certain
types.
This patch addresses that issue by splitting the generic constructor
in two. We now provide both T&& and T const& versions of the
tuple-like constructors (sort of).
llvm-svn: 365973
The paper P0608R3 - "A sane variant converting constructor" disallows
narrowing conversions in variant. It was meant to address this
surprising problem:
std::variant<std::string, bool> v = "abc";
assert(v.index() == 1); // constructs a bool.
However, it also disables every potentially narrowing conversion. For
example:
variant<unsigned> v = 0; // ill-formed
variant<string, double> v2 = 42; // ill-formed (int -> double narrows)
These latter changes break code. A lot of code. Within Google it broke
on the order of a hundred thousand target with thousands of root causes
responsible for the breakages.
Of the breakages related to the narrowing restrictions, none of them
exposed outstanding bugs. However, the breakages caused by boolean
conversions (~13 root causes), all but one of them were bugs.
For this reasons, I am adding a flag to disable the narrowing conversion
changes but not the boolean conversions one.
One purpose of this flag is to allow users to opt-out of breaking changes
in variant until the offending code can be cleaned up. For non-trivial
variant usages the amount of cleanup may be significant.
This flag is also required to support automated tooling, such as
clang-tidy, that can automatically fix code broken by this change.
In order for clang-tidy to know the correct alternative to construct,
it must know what alternative was being constructed previously, which
means running it over the old version of std::variant.
Because this change breaks so much code, I will be implementing the
aforementioned clang-tidy check in the very near future.
Additionally I'm plan present this new information to the committee so they can
re-consider if this is a breaking change we want to make.
I think libc++ should very seriously consider pulling this change
before the 9.0 release branch is cut. But that's a separate discussion
that I will start on the lists.
For now this is the minimal first step.
llvm-svn: 365960
The buildbots were changed to pass -DLIBCXX_CXX_ABI=libcxxabi, but
they don't provide an include path for the library, so cxxabi.h is
never found while building libc++.
This is a temporary change until the buildbots are updated or until
D63883 lands in a form that unbreaks the bots
llvm-svn: 365847
When assigning an initializer list into set/map, libc++ would
leak memory if the initializer list contained equivalent keys
because we failed to check if the insertion was successful.
llvm-svn: 365840
Rather than building up a list to iterate over later, just create multiple
install commands based on the configuration. This makes it easier to see what
is getting installed and allows for the install handling to be centralised. NFC
llvm-svn: 365562
Summary:
Otherwise, when libcxxabi is not an enabled project in the monorepo, we
get a link error because we try to link against non-existent cxxabi_shared.
More generally, we shouldn't change the behavior of the build based on
implicit things like whether a file happens to be at a specific path or
not.
This is a re-application of r365222 that had been reverted in r365233
because it broke the build bots. However, the build bots now specify
explicitly what ABI library they want to use (libc++abi), so this
commit should now be OK to merge.
Differential Revision: https://reviews.llvm.org/D63883
llvm-svn: 365326
The implementations of __libcpp_mutex_destroy and __libcpp_condvar_destroy
are already NOPs, so this optimization is safe to perform.
See r365273 and PR27658 for more information.
llvm-svn: 365281
Currently std::mutex has a constexpr constructor, but a non-trivial
destruction.
The constexpr constructor is required to ensure the construction of a
mutex with static storage duration happens at compile time, during
constant initialization, and not during dynamic initialization.
This means that static mutex's are always initialized and can be used
safely during dynamic initialization without the "static initialization
order fiasco".
A trivial destructor is important for similar reasons. If a mutex is
used during dynamic initialization it might also be used during program
termination. If a static mutex has a non-trivial destructor it will be
invoked during termination. This can introduce the "static
deinitialization order fiasco".
Additionally, function-local statics emit a guard variable around
non-trivially destructible types. This results in horrible codegen and
adds a runtime cost to every call to that function. non-local static's
also result in slightly worse codegen but it's not as big of a problem.
Example codegen can be found here: https://goo.gl/3CSzbM
Note: This optimization is not safe with every pthread implementation.
Some implementations allocate on the first call to pthread_mutex_lock
and free the allocation in pthread_mutex_destroy.
Also, changing the triviality of the destructor is not an ABI break.
At least to the best of my knowledge :-)
llvm-svn: 365273
Summary:
Otherwise, when libcxxabi is not an enabled project in the monorepo, we
get a link error because we try to link against non-existent cxxabi_shared.
More generally, we shouldn't change the behavior of the build based on
implicit things like whether a file happens to be at a specific path or
not.
Reviewers: EricWF
Subscribers: mgorny, christof, jkorous, dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D63883
llvm-svn: 365222
types.
It seems some people like to write types that can explicitly convert
to anything, but cannot be used to explicitly construct anything.
This patch makes tuple tolerate such types, as is required
by the standard.
llvm-svn: 365074
Summary:
This fixes a clang-tidy warning when building something that uses
this file.
Reviewers: mclow.lists, EricWF
Subscribers: cfe-commits
Differential Revision: https://reviews.llvm.org/D43226
llvm-svn: 364799
when _LIBCPP_ABI_UNSTABLE is defined.
User defined _LIBCPP_ABI_NAMESPACE will still be respected,
but the default version namespace in unstable mode will be the libc++ version
(Currently '__9000').
Previously `_LIBCPP_ABI_VERSION` and `_LIBCPP_ABI_NAMESPACE` were
`1` and `__1` respectively, whuch conflicted with the stable ABI
llvm-svn: 364354
Use binary mode to read test files in libcxx LibcxxTestFormat class.
This ensures that tests are read correctly independently of encoding,
and therefore fixes UnicodeDecodeError when file is opened in Python 3
that defaults to pure ASCII encoding.
Technically this could be also fixed via conditionally appending
encoding argument when opening the file in Python 3. However, since
the code in question only searches for fixed ASCII substrings reading
it in binary mode is simpler and more universal.
Differential Revision: https://reviews.llvm.org/D63346
llvm-svn: 364170
The new meta-programming primitives are lower cost than the old versions. This patch removes those old versions and switches libc++ to use the new ones.
llvm-svn: 364160
Clang provides __is_same that doesn't produce any instantiations
and just returns a bool. It's a lot faster than using std::is_same
I'll follow up with a patch to actually start using it.
llvm-svn: 364148
The CMake CheckLibcxxAtomic module was always failing to compile
the example, even when libatomic wasn't needed. This was caused
because the check doesn't link a C++ runtime library to provide
std::terminate, which is required for exception support.
The check is still really broken, but <atomic> is better!
llvm-svn: 364146
Using class templates instead of alias templates causes a lot of
instantiations. As part of the move away from C++03, we want to
improve the efficiency of our meta-programming.
This patch lays the groundwork by introducing new _If, _EnableIf,
_And, _Or, and _IsValidExpansion (detect member). Future patches
will replace the existing implementations after verifying there
compile time differences.
llvm-svn: 364114
These functions are key to allowing the use of rvalues and variadics
in C++03 mode. Everything works the same as in C++11, except for one
tangentially related case:
struct T {
T(T &&) = default;
};
In C++11, T has a deleted copy constructor. But in C++03 Clang gives
it both a move and a copy constructor. This seems reasonable enough
given the extensions it's using.
The other changes in this patch were the minimal set required
to keep the tests passing after the move/forward change. Most notably
the removal of the `__rv<unique_ptr>` hack that was present
in an attempt to make unique_ptr move only without language support.
llvm-svn: 364063
All the compilers we support provide these builtins. We don't
need to do a configuration dance anymore.
This patch also cleans up some dead or almost dead
C++11 feature detection macros.
llvm-svn: 364047
Summary:
The type timespec is unconditionally used in __threading_support.
Since the C library is only required to provide it in C11, this might
cause problems for platforms with external thread porting layer (i.e.
when _LIBCPP_HAS_THREAD_API_EXTERNAL is defined) with pre-C11
C libraries.
In our downstream port of libc++ we used to provide a definition of
timespec in __external_threading, but this solution is not ideal
because timespec is not a reserved name.
This patch renames timespec into __libcpp_timespec_t in the
thread-related parts of libc++. For all cases except external
threading this type is an alias for ::timespec (and no functional
changes are intended).
In case of external threading it is expected that the
__external_threading header will either provide a similar typedef (if
timespec is available in the vendor's C library) or provide a
definition of __libcpp_timespec_t compatible with POSIX timespec.
Reviewers: ldionne, mclow.lists, EricWF
Reviewed By: ldionne
Subscribers: dexonsmith, libcxx-commits, christof, carwil
Tags: #libc
Differential Revision: https://reviews.llvm.org/D63328
llvm-svn: 364012
This is a re-application of r362986 (which was reverted in r363688) with fixes
for the issue that caused it to be reverted.
Thanks to Arthur O'Dwyer for the patch.
Differential Revision: https://reviews.llvm.org/D58587
llvm-svn: 363968
Summary:
AIX system headers need stdint.h and inttypes.h to be re-enterable when macro _STD_TYPES_T is defined so that limit macro definitions such as UINT32_MAX can be found. This patch attempts to allow that on AIX.
Reviewers: hubert.reinterpretcast, jasonliu, mclow.lists, EricWF
Reviewed by: hubert.reinterpretcast, mclow.lists
Subscribers: jfb, jsji, christof, cfe-commits, libcxx-commits, llvm-commits
Tags: #LLVM, #clang, #libc++
Differential Revision: https://reviews.llvm.org/D59253
llvm-svn: 363939
This was found to be broken on Clang trunk. This is a revert of the
following commits (the subsequent commits added XFAILs to the tests
that were missing from the original submission):
r362986: Implement deduction guides for map/multimap.
r363014: Add some XFAILs
r363097: Add more XFAILs
r363197: Add even more XFAILs
llvm-svn: 363688
Summary:
The class ctype_base in the header <__locale> contains masks for
character classification functions, which are kept in sync with
platform's C library, hence it contains many special cases.
The value of the bit mask __regex_word in the header <regex> must not
clash with those bit masks.
Currently the default case (i.e. unknown platform/C library) is
handled incorrectly: the __regex_word clashes with ctype_base::punct.
To avoid replicating the whole list of platforms in <regex> this patch
defines __regex_word in <__locale>, so that it is always kept in sync
with other masks.
Reviewers: ldionne, mclow.lists, EricWF
Reviewed By: ldionne
Subscribers: krytarowski, christof, dexonsmith, pbarrio, simon_tatham, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D63284
llvm-svn: 363363
Summary:
This patch make G++03 explicitly unsupported with libc++, as discussed on the mailing lists.
Below is the rational for this decision.
----------------------------------------------------------------------------------------------------
libc++ claims to support GCC with C++03 ("G++03"), and this is a problem for our users.
Our C++03 users are all using Clang. They must be. Less than 9% of the C++03 tests pass with GCC [1][2]. No non-trivial C++ program could work.
Attempting to support G++03 impacts our QoI considerably. Unlike Clang, G++03 offers almost no C++11 extensions. If we could remove all the fallbacks for G++03, it would mean libc++ could::
* Improve Correctness:
Every `#ifdef _LIBCPP_HAS_NO_<C++11-feature>` is a bug manifest. It exists to admit for deviant semantics.
* Achieve ABI stability between C++03 and C++11
Differences between our C++03 and C++Rest branches contain ABI bugs. For example `std::nullptr_t` and `std::function::operator()(...)` are currently incompatible between C++11 and C++03, but could be fixed.
* Decrease Compile Times and Memory Usage:
Writing efficient SFINAE requires C++11. Using alias templates, libc++ could reduce the number of instantiations it produces substantially.
* Decrease Binary Size
Similar to the last point, G++03 forces metaprogramming techniques that emit more debug information [3] [4]. Compared to libstdc++, debug information size increases of +10% are not uncommon.
Reviewers: ldionne, mclow.lists, EricWF
Reviewed By: ldionne, EricWF
Subscribers: zoecarver, aprantl, dexonsmith, arphaman, libcxx-commits, #libc
Differential Revision: https://reviews.llvm.org/D63154
llvm-svn: 363219
When applied to a typedef or alias template, the [[nodebug]] attribute
makes the typedef transparent to the debugger, so instead of seeing
`std::__function::__alloc_func<remove_reference<void(&)()>::type,
allocator<remove_reference<void(&)()>, void()>::_Target` you see
`void(&)()` as the type of the variable in your debugger.
Removing all this SFINAE noise from debug info has huge binary size
wins, in addition to improving the readability.
For now this change is on by default. Users can override it by
specifying -D_LIBCPP_NODEBUG_TYPE=
llvm-svn: 363117
As we gear up to drop support for GCC in C++03, we should make clear
what our C++03 mode is, the C++11 extensions it provides,
and the C++11 extensions it depends on.
The section of this document discussing user-facing extensions has
been left blank while the community discusses new directions. For now
it's just a warning to users.
Additionally, the document contains examples of how these extensions
should be used and why. For example, using alias templates over class
templates.
llvm-svn: 363110
Summary:
This is not mandated by the Standard, but it's nonetheless a nice
property to have, especially since it's so easy to implement. It
also shrinks our bug list!
PR41714
Reviewers: mclow.lists, EricWF
Subscribers: christof, jkorous, dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D62618
llvm-svn: 363075
Summary:
Following the discussion on the libcxx-dev mailing list
(http://lists.llvm.org/pipermail/libcxx-dev/2019-May/000358.html),
this implements the new policy for handling experimental features and
their deprecation. We basically add a deprecation warning for
std::experimental::filesystem, and we remove a bunch of <experimental/*>
headers that were now empty.
Reviewers: mclow.lists, EricWF
Subscribers: mgorny, christof, jkorous, dexonsmith, arphaman, libcxx-commits, jfb
Tags: #libc
Differential Revision: https://reviews.llvm.org/D62428
llvm-svn: 363072
std::function uses a standard allocator to manage its memory, however
standard allocators are templates and using them correctly requires
a stupid amount of instantiations. This leads to a substantial increase
in debug info and object sizes.
This patch addresses the issue by dropping the allocator when possible
and using raw new and delete to get memory.
This change decreases the object file size for the test func.wrap.func.con/F.pass.cpp by 33% and the final binary by 29% (when compiled with -g -ggnu-pubnames -gpubnames).
It also roughly halfs the number of entries in the pubnames and pubtype
sections.
llvm-svn: 362865
Some tests require `TEST_WORKAROUND_CONSTEXPR_IMPLIES_NOEXCEPT`, but they
did not include the header that defines that macro.
Thanks to Michael Park for the patch.
Differential Revision: https://reviews.llvm.org/D62920
llvm-svn: 362660
This commit adds tests that repeated characters in regular expressions
are within numeric limits, and that a <= b in a regex like `x{a,b}`.
Thanks to Andrey Maksimov for the patch.
Differential Revision: https://reviews.llvm.org/D62816
llvm-svn: 362525
ar doesn't produce the correct results when used for linking static
archives on Apple platforms, so instead use libtool -static which is
the official way to build static archives on those platforms.
Differential Revision: https://reviews.llvm.org/D62770
llvm-svn: 362311
Summary:
This updates all places in documentation that refer to "Mac OS X", "OS X", etc.
to instead use the modern name "macOS" when no specific version number is
mentioned.
If a specific version is mentioned, this attempts to use the OS name at the time
of that version:
* Mac OS X for 10.0 - 10.7
* OS X for 10.8 - 10.11
* macOS for 10.12 - present
Reviewers: JDevlieghere
Subscribers: mgorny, christof, arphaman, cfe-commits, lldb-commits, libcxx-commits, llvm-commits
Tags: #clang, #lldb, #libc, #llvm
Differential Revision: https://reviews.llvm.org/D62654
llvm-svn: 362113
These seemed to have been used in the past but were since removed
by the add_compile_flags_if_supported functions that combine these
these checks and adding the flag, but the original checks were never
removed.
Differential Revision: https://reviews.llvm.org/D62566
llvm-svn: 362058
This fixes the issue introduced by r362048 where we always use
pragma comment(lib, ...) for dependent libraries when the compiler
is Clang, but older Clang versions don't support this pragma so
we need to check first if it's supported before using it.
llvm-svn: 362055
As of r360984, LLD supports dependent libraries feature for ELF.
libunwind, libc++abi and libc++ have library dependencies: libdl librt
and libpthread, which means that when libunwind and libc++ are being
statically linked (using -static-libstdc++ flag), user has to manually
specify -ldl -lpthread which is onerous.
This change includes the lib pragma to specify the library dependencies
directly in the source that uses those libraries. This doesn't make any
difference when using linkers that don't support dependent libraries.
However, when using LLD that has dependent libraries feature, users no
longer have to manually specifying library dependencies when using
static linking, linker will pick the library automatically.
Differential Revision: https://reviews.llvm.org/D62090
llvm-svn: 362048
merged type info names.
Previously std::type_info always expected type info string to be unique.
But this isn't always the case. Like when -Bsymbolic is passed to the
linker or due to llvm.org/PR37398.
This patch adds the LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT CMake
option which, when specified, overrides the default configuration for
the library.
The current defaults still assume unique names even though this isn't
strictly correct for ELF binaries. We should consider changing the
default in a follow up commit.
llvm-svn: 361913
Summary:
This provides the `std::destroying_delete_t` declaration in C++2a and after. (Even when the compiler doesn't support the language feature).
However, the feature test macro `__cpp_lib_destroying_delete` is only defined when we have both language support and C++2a.
Reviewers: ldionne, ckennelly, serge-sans-paille, EricWF
Reviewed By: EricWF
Subscribers: dexonsmith, riccibruno, christof, jwakely, jdoerfert, mclow.lists, ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D55840
llvm-svn: 361572
Summary: On some platforms C++ headers are packaged with the compiler not the sysroot. If you don't copy C++ headers into the build include directory during configuraiton of the outer build the C++ check during the runtime configuration may get inaccurate results.
Reviewers: phosek, compnerd, smeenai, EricWF
Reviewed By: compnerd
Subscribers: EricWF, christof, libcxx-commits, mgorny, llvm-commits
Tags: #llvm, #libc
Differential Revision: https://reviews.llvm.org/D62155
llvm-svn: 361513
Some tests assume that iteration through an unordered multiset elements
will return them in the same order as at the container creation. This
assumption is not true since the container is unordered, so that no
specific order of elements is ever guaranteed for such container. This
patch introduces checks verifying that any iteration will return
elements exactly from a set of valid values and without repetition,
but in no particular order.
Thanks to Andrey Maksimov for the patch.
Differential Revision: https://reviews.llvm.org/D56500
llvm-svn: 361494
This change is a consequence of the discussion in "RFC: Place libs in
Clang-dedicated directories", specifically the suggestion that
libunwind, libc++abi and libc++ shouldn't be using Clang resource
directory. Tools like clangd make this assumption, but this is
currently not true for the LLVM_ENABLE_PER_TARGET_RUNTIME_DIR build.
This change addresses that by moving the output of these libraries to
lib/$target/c++ and include/c++ directories, leaving resource directory
only for compiler-rt runtimes and Clang builtin headers.
Differential Revision: https://reviews.llvm.org/D59168
llvm-svn: 361432
Some tests assume that iteration through an unordered multimap elements
will return them in the same order as at the container creation. This
assumption is not true since the container is unordered, so that no
specific order of elements is ever guaranteed for such container. This
patch is a continuation of D54838 and introduces checks verifying that
any iteration will return elements exactly from a set of valid values
and without repetition, but in no particular order.
Thanks to Andrey Maksimov for the patch.
Differential Revision: https://reviews.llvm.org/D56498
llvm-svn: 361414
The MSVC CRT uses TLS storage to implement per-thread locales.
This storage gets freed during program termination, and if we attempt
to do any io operations (like flushing the std streams) after this occurs
the program may abort.
This patch is a speculative fix for that issue.
The fix tries forcing the initialization of the locale TLS before
initializing the std streams. This should mean that the TLS is freed
after we destroy the streams.
llvm-svn: 361348
The `using namespace std;` opens us up to ambiguity
when any of the std:: names are also present in the global namespace.
Instead we should properly qualify names we use from std::.
llvm-svn: 361074
Use std::nextafter() instead of std::nexttoward() in midpoint tests.
In the context of this test, this should not cause any difference.
Since nexttowardl() is not implemented on NetBSD 8, the latter function
combined with 'long double' type caused test failure. nextafterl() does
not have this problem.
Differential Revision: https://reviews.llvm.org/D61748
llvm-svn: 360673
Eric Fiselier