Summary:
Throughout the libc++ headers, there are a few instances where
_VSTD::move() is used to return a local variable. Howard commented in
r189039 that these were there "for non-obvious reasons such as to help
things limp along in C++03 language mode".
However, when compiling these headers with warnings on, and in C++11 or
higher mode (like we do in FreeBSD), they cause the following complaints
about pessimizing moves:
In file included from tests.cpp:26:
In file included from tests.hpp:29:
/usr/include/c++/v1/map:1368:12: error: moving a local object in a return statement prevents copy elision [-Werror,-Wpessimizing-move]
return _VSTD::move(__h); // explicitly moved for C++03
^
/usr/include/c++/v1/__config:368:15: note: expanded from macro '_VSTD'
#define _VSTD std::_LIBCPP_NAMESPACE
^
Attempt to fix this by adding a _LIBCPP_EXPLICIT_MOVE() macro to
__config, which gets defined to _VSTD::move for pre-C++11, and to
nothing for C++11 and later.
I am not completely satisfied with the macro name (I also considered
_LIBCPP_COMPAT_MOVE and some other variants), so suggestions are
welcome. :)
Reviewers: mclow.lists, howard.hinnant, EricWF
Subscribers: arthur.j.odwyer, cfe-commits
Differential Revision: http://reviews.llvm.org/D11394
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@245421 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: Currently we only enable the use of __is_final(...) with Clang. GCC also provides __is_final(...) since 4.7 in all standard modes. This patch creates the macro _LIBCPP_HAS_IS_FINAL to note the availability of `__is_final`.
Reviewers: danalbert, mclow.lists
Reviewed By: mclow.lists
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D8795
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@239664 91177308-0d34-0410-b5e6-96231b3b80d8
Instead, define explicit specializations for the basic types listed in
the SGI documentation. This solves two problems:
1) Helps avoid silent ODR violations caused by the absence of a
user-supplied __gnu_cxx::hash specialization in cases where a std::hash
specialization exists (e.g. for std::string).
2) __gnu_cxx::hash semantics are slightly different to those of
std::hash (for example, the former may dereference a pointer argument)
so it is inappropriate for __gnu_cxx::hash to receive std::hash
specializations by default.
Differential Revision: http://llvm-reviews.chandlerc.com/D2747
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@203070 91177308-0d34-0410-b5e6-96231b3b80d8
This was checked in without review. It is not clear its reasonable to
include with libc++ at all, and needs discussion at a highlevel before
moving forward.
It's also completely lacking tests, and included several bugs in the
implementation.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136577 91177308-0d34-0410-b5e6-96231b3b80d8
together to get it working with code, and is neither optimal
(erase(Iterator, Iterator) calculates the previous iterator twice,
rather than calculating the previous iterator of the first one, then
advancing it until the second is found) nor complete (splice() was not
implemented). Most of the implementation is borrowed from forward_list
via using-declarations.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136542 91177308-0d34-0410-b5e6-96231b3b80d8
are two motivations for this.
First, this allows users who are specializing __gnu_ext::hash to
continue doing so without changing their code.
Second, SGI specifies hash overloads for char* and const char* that
perform a hash of the string, not of the pointer.
In order to support this, the hashing code for string is factored out.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136539 91177308-0d34-0410-b5e6-96231b3b80d8
the type name 'data_type', which is specified by the SGI spec as being
the correct type name for the mapped type. The second is an overload of
insert found in standard containers, taking an iterator as a 'hint'
(which we ignore in the standard containers as well). libstdc++'s
implementation includes these overloads, and they are needed to make
insert_iterator work (which I suspect is the real motivation for
including them in the standard containers).
The motivation for including these overloads of insert and leaving the
mapped_type typedef is to make it easier for clients to migrate to the
standard containers.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136538 91177308-0d34-0410-b5e6-96231b3b80d8
