Unicode security

[Joseph Myers]

On Mon, 10 Jan 2022, Reini Urban via Binutils wrote:

> So sooner or later some ELF/COFF/bla header field will be needed to state
> the obvious:
> name is UTF-8.

I think that's a matter for the ELF gABI document, where it describes the 
*C binding to ELF* (where it says "External C symbols have the same names 
in C and object files' symbol tables." - which says nothing about 
encoding, since the point of that statement in its historical context was 
probably to imply "no leading underscores added").  That is, ELF symbols 
are arbitrary 0-terminated octet sequences (ELF is not limited to C 
objects, symbols only need to be interpreted when included in diagnostics, 
the assembler and linker should allow you to work with objects with 
arbitrary 0-terminated octet sequences for symbols if you want to, just as 
you can use ASCII characters in ELF symbols that aren't valid in C 
identifiers), but when ELF is used for objects compiled from C, those 
octet sequences for C identifiers with external linkage need to be 
interpreted in a particular way.

Maybe such a change could be proposed on the generic-abi list once Cary's 
public repository is available.

I attempted to get such a statement about UTF-8 encoding of ELF symbols 
for C identifiers with external linkage into the gABI in January 2005, and 
was directed to the ia64-abi@unix-os.sc.intel.com mailing list for that 
purpose.  At that time, the gABI maintainers on that mailing list weren't 
willing to accept such a change, but maybe the current maintainers on the 
current mailing list would be.  If it's still not acceptable for the gABI, 
then an operating-system-specific ABI would be the place to go.

DWARF (version 3 and later) does have DW_AT_use_UTF8.

-- 
Joseph S. Myers
joseph@codesourcery.com