Drew T
2.5 KiB
§171b — THREE CARRIES THE MECHANICAL DRAFT NEEDS (P30 S50, banking the top-reach families)
Working the frontier's top three families end-to-end exposed three carries a seed-body draft needs beyond the symbol rebase. Each was found by reading a single compiler verdict, and each generalises.
1. DATA DEFINED INSIDE THE MEMBER'S OWN .s must be DEFINED, not declared. When a symbol's
bytes live between dlabel/enddlabel in the very .s the draft replaces, an extern links to
nothing — the data vanishes with the stub. Emit the seed's definition re-initialised with this
member's own bytes: they differ per location (the 0x801F1CD8 family carries four distinct
8-byte patterns across 42 members). Substitute only when the initializer is a flat byte list whose
count matches, and refuse otherwise — a partially-understood initializer silently mis-initialised
is a failure the gate catches but nobody can explain. Verdict that names it: undefined reference to 'D_…' on a symbol that visibly exists in the binary's asm.
2. SHARED TYPES the destination cannot see. MATRIX, SVECTOR and friends live in
engine_types.h, which ov_* TUs reach through engine_core.h and md_* TUs do not include at
all. A draft using one in an md module dies as parse error before 'm1' — 4 of the 9
0x8017D290 members, and the only thing between them and a bank. Carry the brace-matched typedef
block, vetoed by the destination (re-declaring a type it already has is a hard C89 error).
3. A POSITIONAL LITERAL MAP where the ordinal engine gives up. imm_map_tier1 refuses a value
that also appears at a NON-differing asm position (asm-ambiguous) — here 0x10, which collides
with the struct offsets param_1 + 0x10. But when the differing slots map 1:1 onto the C's call
sites in order, the substitution is exact: assert [C literals in order] == [seed slot values]
first, then rewrite positionally. That assert is the whole safety argument — it fails loudly if the
C and the asm ever disagree, and it took a family the generic engine had refused 10/10 to 9/9.
AND THE TRAP UNDER ALL THREE: body_text matched extern void func_X(s32, s16 *); at column 0
and returned the next function's body. Silent, and it had been shipping wrong seed bodies —
visible only as "no definition of the member after rename" skips, which read like a niche edge case
and were actually the symptom. A definition is confirmed by a { with no ; before it; a name
match alone never is.