[PATCH] D36138: [ELF] - Don't segfault when accessing location counter inside MEMORY command.

[George Rimar via llvm-commits]

>This LGTM, but a nicer error message would be a good followup.
>
>We might be able to diagnose this in the parser and fuzz a bit more to
>find if anything else gets here too soon.
>
>Cheers,
>Rafael

Thanks ! 

Btw, one of more fuzzed scripts that fixed by this issue was
"PHDRS {all PT_LOAD FILEHDR PHDRS FLAGS (DATA_SEGMENT_RELRO_END ..."

I think we probably can change text from "unable to get location counter value"
to more clear one like "location counter can not be accessed outside of SECTIONS." 
and that should work for all cases we expect.

Rui, what do you think ? Are you ok to land it with/without change to error message text ?

George.