* J. W. Jagersma: > On 2020-02-28 22:32, Florian Weimer wrote: >> * J. W. Jagersma: >> >>> The call instruction is just a practical example. The problem I want to >>> address is that no exception handling information is generated at all >>> for asm statements. Other operations, eg. memory access, division, etc >>> could trap and throw an exception. The unwind tables should cover this. >> >> I think permitted uses of asm cannot do anything that would make the >> tables invalid, at least for DWARF unwinding information. > > I don't see how a trapping instruction in asm would invalidate the > unwind table. An explicit call, maybe, but as I said that was only an > example. The problem is that there is no unwind table at all. > >> DWARF does not need to annotate any instruction that might throw (which >> would be every instruction in case of asynchronous unwind tables). > > But it should, if the instruction appears in a try block. Without that > it is impossible to catch the exception. I don't think this is true. DWARF unwind information is range-based, after all. The asm statement will be covered by the unwinding information for the surrounding code. Thanks, Florian
