On Wed, Nov 4, 2020 at 1:56 PM Hans-Peter Nilsson <h...@bitrange.com> wrote: > > > > On Wed, 4 Nov 2020, H.J. Lu wrote: > > > On Wed, Nov 4, 2020 at 1:03 PM Hans-Peter Nilsson <h...@bitrange.com> wrote: > > > > > > On Wed, 4 Nov 2020, H.J. Lu wrote: > > > > On Wed, Nov 4, 2020 at 10:09 AM Hans-Peter Nilsson <h...@bitrange.com> > > > > wrote: > > > > > > > > > > On Wed, 4 Nov 2020, Jozef Lawrynowicz wrote: > > > > > > I personally do not see the problem with the .retain attribute, > > > > > > however > > > > > > if it is going to be a barrier to getting the functionality > > > > > > committed, I > > > > > > am happy to change it, since I really just want the functionality in > > > > > > upstream sources. > > > > > > > > > > > > If a global maintainer would comment on whether any of the proposed > > > > > > approaches are acceptable, then I will try to block out time from > > > > > > other > > > > > > deadlines so I can work on the fixups and submit a patch in time > > > > > > for the > > > > > > GCC 11 freeze. > > > > > > > > > > > > Thanks, > > > > > > Jozef > > > > > > > > > > I'm not much more than a random voice, but an assembly directive > > > > > that specifies the symbol (IIUC your .retain directive) to > > > > > > > > But .retain directive DOES NOT adjust symbol attribute. > > I see I missed to point out that I was speaking about the *gcc > symbol* attribute "used".
There is no such corresponding symbol attribute in ELF. > > > > Instead, it sets > > > > the SHF_GNU_RETAIN bit on the section which contains the symbol > > > > definition. The same section can have many unrelated symbols. > > > > > > That's an implementation detail *left to the assembler and > > > linker*. It's not something the compiler needs to know, and > > > teoretically it could even change. > > > > > > > The ELF extension is SHF_GNU_RETAIN. .retain directive is a hack > > which I strongly objected and showed that it wasn't needed to implement > > SHF_GNU_RETAIN in binutils. > > It's still an implementation detail better kept in the > assembler, that the mechanism used to retain a symbol for the > compiler, happens to map to a section attribute. Some may call > *that* a hack. > > It's cleaner to the compiler if it can pass on to the assembler > the specific symbol that needs to be kept. > SHF_GNU_RETAIN is for section and GCC should place the symbol, which should be kept, in the SHF_GNU_RETAIN section directly, not through .retain directive. -- H.J.
