Use unique_ptr to manage ownership of GCFunctionInfos in GCStrategy

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206249 91177308-0d34-0410-b5e6-96231b3b80d8
Use unique_ptr to manage TypePromotionActions owned by TypePromotionTransaction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206250 91177308-0d34-0410-b5e6-96231b3b80d8
[Allocator] Constrain the Deallocate templated overloads to only apply
to types which we can compute the size of. The comparison with zero
isn't actually interesting here, it's mostly about putting sizeof into
a sfinae context.

This is particular important for Deallocate as otherwise the void*
overload can quickly become ambiguous.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206251 91177308-0d34-0410-b5e6-96231b3b80d8
[C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206252 91177308-0d34-0410-b5e6-96231b3b80d8