> By saying that .debug_frame supports shrink wrapping, do you also mean that > it supports the “two paths join with different register state” case? Which > means it’s only a matter of the .cfi_xxx directives, and if I were to build > the .debug_frame/.eh_frame section by hand I would be fine?
No, I don't believe that it can in general. There's no way to express a conditional "if p then DW_CFA_def_offset else DW_CFA_def_same_value", for example. If a register is spilled to the stack in both paths, but at different offsets, you could encode it with DW_CFA_def_offset, using a DWARF expression that evaluates to different values based on a condition, but this technique would be limited to the case where you could use DW_CFA_def_offset for both paths. I think this would also lead to some undesirable bulk in your .debug_frame or .eh_frame sections. And I'm not actually sure whether the unwinder (Which unwinder? There are several!) completely supports DWARF expressions in that context. -cary _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
