Michael137 wrote: > While logically correct I think we might have to teach LLDB how to handle > this. LLDB has a special "frame recognizer" where it looks for frames using > this fake debug info mechanism (e.g. __builtin_verbose_trap) and it assumes > the frame below it is the real source code and automatically selects this > frame when trapping so that the user sees the correct source location when > the trap is hit. If the frame below the fake frame isn't the user's code and > is instead another fake frame this won't work properly.
Yea everything that @delcypher said here is accurate from the LLDB-side. Here's the logic that LLDB uses to pick which frame to display: https://github.com/llvm/llvm-project/blob/9ba332f9963561bb5ac6933266afe38eb8fde8cd/lldb/source/Target/VerboseTrapFrameRecognizer.cpp#L22-L50 Currently we just pick the frame just above the fake inlined frame (and skip over any `std::` frames). We can definitely adjust the heuristic to accommodate the case where we have another fake frame above the UBSan trap one. > It's probably possible to make LLDB work with which ever top frame we decide > but we'd probably want the fake frame names be easily recognizable and stable > so that LLDB's feature continues to work reliably. Agreed, for the `__builtin_verbose_trap` we picked `__clang_trap_msg` as the prefix for the fake frame. And that's how LLDB knows to activate the frame recognizer: https://github.com/llvm/llvm-project/blob/9ba332f9963561bb5ac6933266afe38eb8fde8cd/lldb/source/Target/VerboseTrapFrameRecognizer.cpp#L145-L146 We'll want a similar prefix for any other fake frames that LLDB is supposed to recognize > Given that -fsanitize-annotate-debug-info is off by default my suggestion is > that @anthonyhatran land the simplest version of his patch possible by not > concerning himself with -fsanitize-annotate-debug-info at this stage. And > after it's landed we can then decide how to make the two features interact in > a way that the LLDB folks are happy with. Agreed https://github.com/llvm/llvm-project/pull/141997 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
