Summary:
Recent commits broke the check-cxx-abilist by changing the default OS X to use `-rexport_library` instead of `-reexport_symbol_list`. Apparently `-reexport_library` doesn't export the symbols into `libc++.dylib`s symbol table, whereas `-reexport_symbol_list` does.
This means the change removed ~500 symbols from the symbol table. I've been told this change is non ABI breaking, but it does make it harder to maintain the ABI lists, and hence the ABI.
This patch fixes the issue by switching back to `-reexport_symbol_list`. It still avoid the issues fixed in r299052 by putting the new/delete symbols in a different symbol list file, which is only exported when LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS in OFF.
Reviewers: mehdi_amini, smeenai, dexonsmith
Reviewed By: smeenai
Subscribers: mgorny, cfe-commits
Differential Revision: https://reviews.llvm.org/D31644
llvm-svn: 300390
Both libc++ and libc++abi export a weak definition of operator
new/delete. On Darwin, this can often cause dirty __DATA in the
shared cache when having to switch from one to the other. Instead,
libc++ should reexport libc++abi's implementation of these symbols.
Patch by: Ted Kremenek <kremenek@apple.com>
Differential Revision: https://reviews.llvm.org/D30765
llvm-svn: 299054
Summary:
On OS X libc++ needs to reexport libc++abi's symbols in order for them to be provided. We explicitly list the symbols to reexport it libcxx/lib/libc++abi2.exp. This patch adds the symbols required by std::bad_array_length which have been missing for some time.
However there is a problem. std::bad_array_length was add to libc++abi in September of 2013 by commit r190479, about a year after everything else. Therefore I think older OS X version have libc++abi versions without std::bad_array_length. On those systems
libc++ won't build with this change because we will try and export undefined symbols.
The workaround I would write to support older systems depends on the amount of people who would need it. If only a small number of developers are affected it might be sufficient to provide a CMake switch like `LIBCPP_LIBCPPABI_HAS_BAD_ARRAY_LENGTH` which is
ON by default and can be disabled by those who need it. Otherwise I think we should try to automatically detect if the symbols are present in `/usr/lib/libc++abi.dylib` and configure accordingly. I would prefer the first solution because writing CMake sucks.
Reviewers: mclow.lists, aprantl
Subscribers: aprantl, cfe-commits
Differential Revision: http://reviews.llvm.org/D13445
llvm-svn: 249339
Eric Fiselier