[PATCH v2] elf: Add DL_ADDRESS_WITHOUT_RELOC [BZ #33088]

[Florian Weimer]

* Alexander Monakov:

> On Mon, 16 Jun 2025, Florian Weimer wrote:
>
>> > @@ -428,7 +429,7 @@ static ElfW(Addr) _dl_start_final (void *arg,
>> >  
>> >  /* These are defined magically by the linker.  */
>> >  extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
>> > -extern char _end[] attribute_hidden;
>> > +extern char _end attribute_hidden;
>> 
>> Can you avoid this change (which may have unintended side effects on
>> other architectures) if you use
>> 
>> > +  ({ __typeof (+var) _result = var; asm ("" : "+r"(_result)); _result; })
>> 
>> in the definition of DL_ADDRESS_WITHOUT_RELOC?
>
> It won't work, but __auto_type, available since gcc-4.9 and clang-3.8,
> will:
>
>   __auto_type _result = val;
>
> or something like '__typeof(0 ? val : 0)' can be used for
> array-to-pointer decay inside of typeof.

Why doesn't it work?  Shouldn't the + trigger decay from array to
pointer?  Maybe it needs another one?

Thanks,
Florian