[PATCH] D67774: [Mangle] Add flag to asm labels to disable '\01' prefixing

[John McCall via cfe-commits]

On Tue, Jan 7, 2020 at 3:02 PM Aaron Ballman <aaron at aaronballman.com> wrote:
> On Tue, Jan 7, 2020 at 2:57 PM John McCall via cfe-commits
> <cfe-commits at lists.llvm.org> wrote:
> > On Tue, Jan 7, 2020 at 1:44 PM Aaron Ballman via Phabricator
> > <reviews at reviews.llvm.org> wrote:
> > > Sorry to dredge up an old review, but I recently ran into a bug in this area and am not certain of how to fix it. What should happen if the asm label is a literal which is empty?
> >
> > The problems here are unique to empty labels, right?
>
> To the best of my knowledge, yes.
>
> > Can we just
> > diagnose this as an error?
>
> I don't think so -- GCC's function attribute documentation seems to
> suggest you should do this with noinline functions (see the docs for
> noinline here https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#Common-Function-Attributes)

That's an assembly statement, not a label.

> > Is this bug occurring with real code, or
> > is LLDB constructing something bizarre?
>
> It was a c-reduced test case that we found when doing AST dumping to
> JSON, so I think the code was probably real at one point.

Unless your reducer is smart enough to try to minimize string
literals, which it might be.

John.