Previously, we would have a private backing variable and an internal
alias pointing at it.
However, -fdata-sections only fires if a global variable has non-private
linkage. This means that an unreferenced vftable wouldn't get
discarded, bloating the object file.
Instead, stick the backing variable in a comdat even if the alias has
internal linkage. This will allow the linker to drop the vftable if it
is unused.
llvm-svn: 212901
Comdat IR references were mistakenly printed for aliases when they
passed through the IR/AsmWriter code.
This makes clang's tests not check for the existance of these wrongly
printed comdat references.
llvm-svn: 212733