This was originally broken by r258744 which introduced a weak reference
from ubsan to ubsan_cxx. This reference does not work directly on
Windows because COFF has no direct concept of weak symbols. The fix is
to use /alternatename to create a weak external reference to ubsan_cxx.
Also fix the definition (and the name, so that we drop cached values)
of the cmake flag that controls whether to build ubsan_cxx. Now the
user-controllable flag is always on, and we turn it off internally
depending on whether we support building it.
Differential Revision: https://reviews.llvm.org/D37882
llvm-svn: 313391
Avoid crashing when printing diagnostics for vtable-related CFI
errors. In diagnostic mode, the frontend does an additional check of
the vtable pointer against the set of all known vtable addresses and
lets the runtime handler know if it is safe to inspect the vtable.
http://reviews.llvm.org/D16824
llvm-svn: 259717
Evgeniy Stepanov