We're only doing it with -flto currently, however it never "hurt"
to pass it, and users that are linking without -flto can get in
trouble if one of the dependency (a static library for instance)
contains bitcode.
Differential Revision: https://reviews.llvm.org/D25932
llvm-svn: 285254
Reapply r248935.
Usually, when using LTO with a clang installation newer than the
system's one, there's a libLTO.dylib version mismatch and LTO fails. One
solution to this is to make ld point to the right libLTO.dylib by
changing DYLD_LIBRARY_PATH.
However, ld64 supports specifying the complete path to the desired
libLTO.dylib through the -lto_library option. This commit adds support
for the clang driver to use this option whenever it's capable of finding
a libLTO.dylib in clang's installed library directory. This way, we
don't need to rely on DYLD_LIBRARY_PATH nor get caught by version
mismatches.
Differential Revision: http://reviews.llvm.org/D13117
rdar://problem/7363476
llvm-svn: 249143
Mehdi Amini