jmorse wrote: There's precedent for splitting the debug-info into fragments early, we do something similar for C++ structured-bindings in SROA and a very similar process happens when the i128 argument is split up in instruction-selection.
Split-up locations become brittle to optimisations though: any source-expression that gets salvaged into a DIExpression can't be decomposed into two fragments, and we have to mark them optimised out. Any salvaging into DIExpression for an i128 will almost certainly fail when the value gets split up in isel. Plus I believe DWARF doesn't support values on the expression stack larger than the machine-address-size, but that's an assumption that can be bent. Presumably the desire here is to improve the variable availability of parameters rather than fully supporting i128's through LLVM debug-info? If so, the least invasive approach may be to teach SROA to decompose into fragments similar to structured-bindings for the first variable location in the function. Or, passing an i128 instead works alright, I have no opinion on ABI matters. (Paging @OCHyams as he worked on structured bindings; and @slinder1 as this is another scenario that might be easier with a typed expression stack) https://github.com/llvm/llvm-project/pull/135230 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
