[llvm-dev] Question regarding correctness of debug information generated by LLC

[via llvm-dev]

> Sorry for the late reply, this is my first day back after a long
> holiday weekend. The gist of your reply seems to be that it's a little
> hard to determine what might be going wrong because there is no debug
> information in the IR I shared. There was debug information in my
> original IR, it's true, but I was still able to reproduce the issue I
> was encountering whether or not the debug information was present, so
> it got removed during the process of minimization. The reason I
> considered this normal is because LLC still generates CFI/CFA
> directives in the assembly even when no debug information is present
> in the IR, and my understanding was that this was the information that
> the debugger used in order to unwind the stack.

Ah, okay, I misunderstood.  The CFI/CFA directives are not what I
normally think of as debug information, although of course they are
used to build the unwind tables in the .debug_frame section (or in
the .eh_frame section, if you're not producing debug info).

I suspect you are not targeting an X86-family architecture?  I was
not able to persuade llc for x86_64 Ubuntu to emit the tail calls
that you describe.  Could you provide a complete llc command line
(including triple) that demonstrates the problem for you?

Thanks,
--paulr