llvm-project

2f0910d2 - [C++20] [Modules] Skip ODR checks if either declaration comes from GMF

[C++20] [Modules] Skip ODR checks if either declaration comes from GMF This patch tries to workaround the case that: - in a module unit that imports another module unit - both the module units including overlapped headers - the compiler emits false positive ODR violation diagnostics for the overlapped headers if ODR check is enabled - the current module units enables PCH For the third point, we disabled ODR check if the declarations comes from GMF. However, due to the forth point, the check whether the declaration comes from GMF failed. Then we still going to check it and then the users get false positive checks. What's worse is that, this always happens in clangd, where will generate the PCH automatically before parsing the input files. The root cause of the problem we mixed the modules in the semantical level and the module in the serialization level. The problem is pretty fundamental and we need time to fix that. But 19.x is going to be branched and I hope to give clangd better user experience. So I decided to land this workaround even if it is pretyy niche and may only work for the case of clangd's pattern.