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
Things done in this patch:
1. Make __debug include __config since it uses macros from it.
2. The current method of defining _LIBCPP_ASSERT is prone to redefinitions. Move
the null _LIBCPP_ASSERT definition into the __debug header to prevent this.
3. Remove external <__debug> include gaurds. <__debug> guards almost all of its
contents internally. There is no reason to be doing it externally.
This patch should not change any functionality.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@215332 91177308-0d34-0410-b5e6-96231b3b80d8
unordered_set, however it is not complete yet for unordered_multiset,
unordered_map or unordered_multimap. There has been a lot of work done
for these other three containers, however that work was done just to
keep all of the tests passing.
You can try this out with -D_LIBCPP_DEBUG2. You will have to link to a
libc++.dylib that has been compiled with src/debug.cpp. So far, vector
(but not vector<bool>), list, and unordered_set are treated. I hope to
get the other three unordered containers up fairly quickly now that
unordered_set is done.
The flag _LIBCPP_DEBUG2 will eventually be changed to _LIBCPP_DEBUG, but
not today. This is my second effort at getting debug mode going for
libc++, and I'm not quite yet ready to throw all of the work under the
first attempt away.
The basic design is that all of the debug information is kept in a
central database, instead of in the containers. This has been done as
an attempt to have debug mode and non-debug mode be ABI compatible with
each other. There are some circumstances where if you construct a
container in an environment without debug mode and pass it into debug
mode, the checking will get confused and let you know with a readable
error message. Passing containers the other way: from debug mode out to
a non-debugging mode container should be 100% safe (at least that is the
goal).
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@186991 91177308-0d34-0410-b5e6-96231b3b80d8
