This happened because we had a section
```
- Index: 3
Kind: DATA
Name: weak_import_data
Flags: [ BINDING_WEAK, UNDEFINED ]
```
Which does not have size. We managed to reproduce it by building llvm
under msan with libcxx as a standard library and debug mode with
-D_LIBCPP_DEBUG_STRICT_WEAK_ORDERING_CHECK. It called comp(a, a) and
full tie detected uninitialized memory
This started to happen after https://reviews.llvm.org/D158799
aea0ea57b7