[EXTERNAL] Re: [PATCH] RISC-V: Do not gp relax against an ABS symbol if it is far away.

[Maciej W. Rozycki]

On Tue, 8 Aug 2023, Joseph Faulls wrote:

> > What's the use case for using AUIPC/LW to load an absolute symbol?  
> > Such symbols are not used in contexts where an address could 
> > alternatively be expected, so the correct sequence, and in PIC or PIE 
> > code indeed the only valid, for direct references from code is 
> > LUI/ADDI
> 
> For my clarification, are you saying that the AUIPC/LW should never have 
> been generated? If so, how is it possible for the compiler to know that 
> the symbol referenced will be an absolute symbol?

 No, the compiler won't ever know that a reference will ultimately resolve 
to an absolute symbol; I don't think there's a way to tell it.  Then such 
symbols aren't usually used in compiled code as they are awkward to refer 
to (e.g. in C you'll only ever use `&symbol' to get at one).  Most often 
I'd expect them to be referred in handcoded assembly, via the LI macro, 
and possibly defined via the GAS's or LD's `--defsym' command-line option, 
or in a linker script.

  Maciej