Rework exception matching.

- Remove typeinfo since thing break if the compiler decides to use the
  system one and merge its contents into typeinfo.h
- Make each type_info object have a vtable with the same layout as the
  public vtable in libstdc++'s <typeinfo>.  This fixes code (e.g.
  libobjc2's Objective-C++ exception handling) which rely on being able
  to add new types.
- Add some extra tests

I suspect exceptions catching pointer-to-member types will not work
correctly, but I've never seen anyone do this and don't have any tests
for it.
It appears that the standard accidentally removed the default constructor for error_category.  I'm putting it back in.  This fixes http://llvm.org/bugs/show_bug.cgi?id=12321.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153194 91177308-0d34-0410-b5e6-96231b3b80d8
Rearrange the virtual functions in type_info to match the gcc layout,
rather than the FreeBSD layout.
Ensure the correct happens-before relationship between set / get
functions.

Add the C++11 std::get_new_handler().
Correctly handle the case where 0 is passed to operator new.
Small doc tweak.
I believe tuple is still under development in the standard.  Daniel Krugler is/will be making convincing arguments that a modified form of LWG 2051 (currently NAD Future) is easily acheivable and desirable.  He has demonstrated that a tuple<T...> where all of the T are implicitly convertible from U... should have a tuple constructor that is also implicit, instead of explicit.  This would support the use cases in LWG 2051 while not undermining T... with explicit conversions from U....  This check-in is an experimental implementation of Daniel's work.  I believe this work to be mature enough to warrant inclusion into libc++.  If anyone sees real-world problems that this check in causes, please let me know and I will revert it, and provide the feedback to the LWG.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153855 91177308-0d34-0410-b5e6-96231b3b80d8
This is an initial commit of constexpr support as proposed by Richard Smith.  This by no means completes constexpr support.  Indeed, it hardly scratches the surface.  All it does is lay the foundation in <__config> and changes those few places in the library that are already using that foundation.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153856 91177308-0d34-0410-b5e6-96231b3b80d8
Fix test for default constructor of discrete_distribution.  This partially addresses http://llvm.org/bugs/show_bug.cgi?id=12436.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153873 91177308-0d34-0410-b5e6-96231b3b80d8
Update <limits> with constexpr support.  Patch contributed by Jonathan Sauer.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153888 91177308-0d34-0410-b5e6-96231b3b80d8
Update <random> with constexpr support.  Patch contributed by Jonathan Sauer.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153896 91177308-0d34-0410-b5e6-96231b3b80d8
Updated documentation contributed by Christopher Jefferson.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153955 91177308-0d34-0410-b5e6-96231b3b80d8
constexpr support for <utility>.  Patch contributed by Jonathan Sauer.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153968 91177308-0d34-0410-b5e6-96231b3b80d8
Put std::piecewise_construct_t back into the dylib for ABI stability.  When clients are in C++11/constexpr mode this will be safely ignored because piecewise_construct is then declared with internal linkage.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@153981 91177308-0d34-0410-b5e6-96231b3b80d8
Fix use of __atomic_is_lock_free() intrinsic.



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@154093 91177308-0d34-0410-b5e6-96231b3b80d8
Fix test cases that were trying to make atomic things that are not trivially copyable.

Now all of the test cases compile.  Some of them even run!



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@154094 91177308-0d34-0410-b5e6-96231b3b80d8
Fix the remaining atomic tests, all of which were wrong for the case where a
compare-and-exchange failed (it should update the expected value to the current
value, and the tests were checking that it didn't...).

Results of the atomics part of the test suite on FreeBSD with clang trunk and
the atomic.c from compiler-rt (currently kludged into the test, not installed
properly):

****************************************************
Results for /root/libc++/test/atomics:
using clang version 3.1 (trunk 153415)
Target: x86_64-unknown-freebsd10.0
Thread model: posix
with -std=c++0x -stdlib=libc++ -pthread /tmp/atomic.o  
----------------------------------------------------
sections without tests   : 0
sections with failures   : 0
sections without failures: 14
                       +   ----
total number of sections : 14
----------------------------------------------------
number of tests failed   : 0
number of tests passed   : 52
                       +   ----
total number of tests    : 52
****************************************************

Yay!



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@154095 91177308-0d34-0410-b5e6-96231b3b80d8
Now that clang supports doing the right thing with regard to atomic
initialisation, do the right thing with regard to atomic initialisation.

Note: clang r154507 or later required for <atomic> to work now.



git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@154508 91177308-0d34-0410-b5e6-96231b3b80d8
Switch libc++ from __atomic_* builtins to __c11_atomic_* builtins.
Per discussion with Howard, we are not interested in maintaining
compatibility with older versions of clang.

All tests pass with ToT clang, except for two which assert due to
a pre-existing, unrelated bug.


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@154521 91177308-0d34-0410-b5e6-96231b3b80d8
Apply noexcept and constexpr to <atomic>.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@154526 91177308-0d34-0410-b5e6-96231b3b80d8