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
Vitaly Buka