Re: Thread Specific Architectures And Python Unwinder API
Luis Machado via Gdb <[email protected]>
| Newsgroups | gmane.comp.gdb.devel |
|---|---|
| Message-ID | <[email protected]> |
On 10/12/23 14:02, Andrew Burgess wrote: > Luis Machado <[email protected]> writes: > >> On 10/11/23 11:06, Luis Machado wrote: >>> Hi Andrew, >>> >>> On 10/11/23 09:47, Andrew Burgess wrote: >>>> >>>> Hi Luis, >>>> >>>> While working on something else I was looking at the Python Unwinder API >>>> code, and I suspect that the thread-specific architectures support might >>>> (currently) break the Python Unwinder support. >>>> >>>> If it is, then I think the fix is pretty simple, but before I posted it, >>>> I wondered if you could confirm that things are indeed, currently >>>> broken. >>>> >>>> Attached at the end of this email is a Python unwinder. You'll need to >>>> supply your own test program that makes use of sve/sme, and thus uses >>>> thread-specific architectures. >>>> >>>> What you'll need to do is: >>>> >>>> $ gdb -q test_file_that_uses_sve_sme >>>> Reading symbols from .... etc ... >>>> (gdb) source ./unwinder.py >>>> (gdb) break function_where_a_thread_specific_arch_will_be_in_use >>>> Breakpoint 1 at ... etc ... >>>> (gdb) run >>>> Starting program: ... etc ... >>>> >>>> Now at this point, when you stop, you should see at least one instance >>>> of the banner: >>>> >>>> *********************************** >>>> * Have executed the test unwinder * >>>> *********************************** >>>> >>>> being printed, probably more. As you step though the function you >>>> should see more instances of the banner being printed. >>>> >>>> To reveal the bug then it is important that when GDB stops in >>>> function_where_a_thread_specific_arch_will_be_in_use, the per-thread >>>> gdbarch that it creates _must_ be different from the inferior wide, >>>> top-level gdbarch. >>>> >>>> If you don't see the banner then my suspicion is correct, and the Python >>>> Unwinder API was broken when the thread-specific architecture support >>>> was added. >> >> I've confirmed I don't see the banner. So this seems to be broken. >> >> Is the fix to set the python unwinder hook elsewhere? Or maybe save that >> information when we're trying to pick a different gdbarch? > > I'll post my patch for this later today. But I'm going to propose > changing the 'architecture_changed' observable into a 'new_architecture' > observable (which is called in a different place). As such, every new > architecture will have the Python unwinder registered correctly. > > I just need to update the commit message with some details of this issue > as justification for the change, and I'll post it -- it's a pretty small > change. I'll CC you on the new thread. Great. Thanks for the heads-up. Let me know if you need some more testing.