On 5/10/22 02:15, Pedro Alves via Dwarf-Discuss wrote:
But still, at the language level, the types ARE different. And DWARF is also about language source to machine code mapping. C/C++ don't let you take the address of a bitfield, for example, so it's possible type expressions in the debugger that behave differently depending on what the DWARF described.
In a previous email in this thread, I mentioned that I thought "char a;" and "char a:8" in a struct were equivalent. I forgot about the restriction on using the address operator, mentioned in ISO C Sect. 6.5.3.2 (at least, in the old copy I have). They are not equivalent. Thanks for reminding me.
So in my view, you'd want a producer to always indicate that the field is a bitfield somehow, even if the memory layout wouldn't change, i.e., regardless of ABI. Maybe we can convince Clang folks of the same as GCC, that certainly sounds simpler, but I figured that maybe there would be agreement that the spec itself should be tweaked in this direction, if every producer would come to the same conclusion.
It's better to propose a change to the DWARF Standard. You can submit a proposal on the Public Comment page: https://dwarfstd.org/Comment.php. Describe the issue briefly and, if possible, please specify the change to the wording of the DWARF Standard that would think appropriate. -- Michael Eager _______________________________________________ Dwarf-Discuss mailing list Dwarf-Discuss@lists.dwarfstd.org http://lists.dwarfstd.org/listinfo.cgi/dwarf-discuss-dwarfstd.org
