The unique_ptr prettyprinter calls `GetValueOfLibCXXCompressedPair`,
which looks for a `__value_` child. However, when the second value in
the compressed pair is not an empty class, there are two `__value_`
children because `__compressed_pair` derives twice from
`__compressed_pair_elem`, one for each member of the pair. And then the
lookup fails because it's ambiguous.
This patch makes the following changes:
- Rename `GetValueOfLibCXXCompressedPair` to
`GetFirstValueOfLibCXXCompressedPair`, and add a similar function to
get the second value. Put both functions in
Plugin/Language/CPlusPlus/LibCxx.cpp because it seems inappropriate to
have libcxx-specific helpers separate from all the libcxx-dependent
code.
- Read the second value of the `__ptr_` pair and display a "deleter"
child in the unique_ptr synthetic child provider, when available.
- Add a test case for the non-empty deleter case.
Differential Revision: https://reviews.llvm.org/D148662
d366da97bd