debuginfo-tests: Add support for an lldb wrapper script
to be used on darwin in lieu of gdb.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190186 91177308-0d34-0410-b5e6-96231b3b80d8
Debug Info Testing: Updated to use null instead of "i32 0" for containing-type
field of DICompositeType.

This will help the follow-on patch of using DITypeRef for containing-type field.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190187 91177308-0d34-0410-b5e6-96231b3b80d8
Debug Info: Move a helper function getTypeIdentifier from DIBuilder to be part
of DIType.
    
Implement DIType::generateRef to return a type reference. This function will be
used in setContaintingType and in DIBuilder to generete the type reference.
    
No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190188 91177308-0d34-0410-b5e6-96231b3b80d8
Debug Info: Use identifier to reference DIType in containing type field of
a DICompositeType.
    
Verifier is updated accordingly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190190 91177308-0d34-0410-b5e6-96231b3b80d8