llvm-project

c660b281 - [lldb][SymbolFileDWARF] Ignore Declaration when searching through UniqueDWARFASTTypeList in C++ (#120809)

[lldb][SymbolFileDWARF] Ignore Declaration when searching through UniqueDWARFASTTypeList in C++ (#120809) This addresses an issue encountered when investigating https://github.com/llvm/llvm-project/pull/120569. In `ParseTypeFromDWARF`, we insert the parsed type into `UniqueDWARFASTTypeMap` using the typename and `Declaration` obtained with `GetUniqueTypeNameAndDeclaration`. For C++ `GetUniqueTypeNameAndDeclaration` will zero the `Declaration` info (presumably because forward declaration may not have it, and for C++, ODR means we can rely on fully qualified typenames for uniqueing). When we then called `CompleteType`, we would first `MapDeclDIEToDefDIE`, updating the `UniqueDWARFASTType` we inserted previously with the `Declaration` of the definition DIE (without zeroing it). We would then call into `ParseTypeFromDWARF` for the same type again, and search the `UniqueDWARFASTTypeMap`. But we do the search using a zeroed declaration we get from `GetUniqueTypeNameAndDeclaration`. This particular example was fixed by https://github.com/llvm/llvm-project/pull/120569 but this still feels a little inconsistent. I'm not entirely sure we can get into that situation after that patch anymore. So the only test-case I could come up with was the unit-test which calls `MapDeclDIEToDefDIE` directly.