Unblock literal initialisers for str/slice/struct globals by wiring
an R_X86_64_64 relocation kind through both assembler and static
linker.
w6a:
- new A_DATAR directive, syntax `DATAR slot+off(SB),target(SB)`,
records an R_X86_64_64 reloc at slot+off in .data pointing at
target. The slot must be pre-defined by a prior DATAW;
- parse_operand learned the `name+disp(SB)` shape so the slot's
byte offset can be addressed explicitly;
- Areloc carries a `section` flag (0=.text / 1=.data) and obj.c
splits the reloc list into .rela.text and .rela.data, emitting
the latter conditionally with sh_info pointing at .data.
w6l:
- Lrel grows the same `section` flag; obj.c loads `.rela.data`
sections into the global reloc list with offsets shifted by
each input's data_off;
- pass.c handles R_X86_64_64: target VA is data_va+sym.val for
in_data symbols (else text_va+sym.val), addend is added, and
the 8-byte slot is patched in l->data (or l->text).
Inputs without DATAR are unaffected — bootstrap, 991 (selfhost .o
diff) and 992 (selfhost exe diff) keep their byte-identical
output. 520_datar covers the new path: asm a DATAW+DATAR pair,
verify .rela.data has exactly one R_X86_64_64 entry, link, run,
confirm the relocated pointer feeds a 5-byte write that prints
"hello".
Selfhost mirror + w6c emission for str/slice/struct literal init
land in follow-ups.
Hojun-Cho
d998425391