[Bug sanitizer/82501] AddressSanitizer does not handle negative offset for first global variable

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82501

--- Comment #24 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Martin Liška from comment #23)
> (In reply to Andrey Drobyshev from comment #22)
> > Created attachment 45851 [details]
> > Work-in-progress fix considering relocations
> > 
> > I'm a bit stuck. I managed to precompute reloc value for the globals (the
> > code for detect_reloc_for_node() is stealed from get_variable_section ()). I
> > also succeded in putting dummy variable into .data.rel.ro by making a decl
> > of a pointer type.
> 
> Nice progress!
> 
> > But .data.rel is not working: checks from varasm.c:1173
> > and varasm.c:1197 are somewhat conflicting. Maybe you could find a way to
> > overcome this?
> 
> Can you please paste content of the lines, the lines you mentioned point to
> a '}' for me.

I would like to ask, has the idea of adding an artificial object linked with
-fsanitize=address early on the link line which would register artificial dummy
variables in at least the most common data sections been considered and
rejected?
I mean, it should at least for large libraries mean significantly fewer dummy
variables, on the other side, when mixing sanitized and non-sanitized objects
within one binary/library (having sanitized ones first and then say linking a
static library non-sanitized would be fine) would mean catching up fewer
issues.