[lldb] Refactor away UB in SBValue::GetLoadAddress (#141799)

The problem was in calling GetLoadAddress on a value in the error state,
where `ValueObject::GetLoadAddress` could end up accessing the
uninitialized "address type" by-ref return value from `GetAddressOf`.
This probably happened because each function expected the other to
initialize it.

We can guarantee initialization by turning this into a proper return
value.

I've added a test, but it only (reliably) crashes if lldb is built with
ubsan.

1 files changed, 1 insertions, 3 deletions

diff --git a/lldb/source/Expression/Materializer.cpp b/lldb/source/Expression/Materializer.cpp
index 8d48b5e..79c804c 100644
--- a/lldb/source/Expression/Materializer.cpp
+++ b/lldb/source/Expression/Materializer.cpp
@@ -508,10 +508,8 @@ public:
         return;
       }
     } else {
-      AddressType address_type = eAddressTypeInvalid;
-      const bool scalar_is_load_address = false;
       lldb::addr_t addr_of_valobj =
-          valobj_sp->GetAddressOf(scalar_is_load_address, &address_type);
+          valobj_sp->GetAddressOf(/*scalar_is_load_address=*/false).address;
       if (addr_of_valobj != LLDB_INVALID_ADDRESS) {
         Status write_error;
         map.WritePointerToMemory(load_addr, addr_of_valobj, write_error);