selfhost — ww reimplementation of the toolchain (wcc, w6c, w6a, w6l, ww, wwdump). Compiled by the C bootstrap (`../cmd/`); the goal is to eventually compile itself.

Identifiers: Plan 9 style. lowercase, words run together (`newbuf`, `tcpsock`, `parsefile`). No snake_case.

Syntax and idioms: Hare-shaped. Trailing `;`, `=` after fn/type signatures, `export` for visibility, `match`/`?`/`!` for tagged-union errors. Consult `ref/hare/` for canonical signatures and error-handling patterns before inventing your own.

The C bootstrap's cgen has known silent-miscompilation traps. They produce wrong runtime behavior, not compile errors. When porting C → ww here, default to the workarounds:

1. **`amalloc(n)` with n < struct size silently corrupts neighbours.** No error — the bump arena hands out n bytes and field writes overflow into the next record. When introducing or growing a struct, audit every `amalloc(_, n)` call site and over-size (we routinely pass 48 for a 40-byte struct). Symptom: linked-list prepends lose all but the most recent entry.

Fixed (no workaround needed):

- `def NAME: str = "..."` field access. `.len`/`.ptr` on an Sdef ident
  now inline the literal length / strlit address rather than reading
  BP+8. See cmd/w6c/cgen.c N_DOT.
- Two-level field write through pointer field: `r.sym.isdyn = 1` where
  `r.sym: *T` now stores. The chained-N_DOT N_ASSIGN branch evaluates
  the inner pointer and stores at *(ptr + field.offset). See
  cmd/w6c/cgen.c N_ASSIGN and selfhost/cmd/wcc/cgenexpr.ww cgassign.
- Tuple return `(scalar, str)` (24B). Returns now follow an AX:DX:CX
  convention: AX = scalar elem, DX = str.ptr, CX = str.len. Receive
  sites all destructure off the same regs regardless of positional
  order:
    let n, s = call();           // ww comma form
    let (n, s) = call();         // Hare-style paren form
    let t: (i64, str) = call();  // positional t.0 / t.1.len
  Wwstage parser + cgen are byte-identical to C cgen on these shapes.
  See cmd/w6c/cgen.c N_RETURN/N_LET/N_DOT/N_MLET, lib/ww/parse/{stmt,
  expr}.ww and selfhost/cmd/wcc/{cgenstmt,cgenexpr,cgenutil,cgendecl}.ww.

If a port "should work" but the binary is wrong, suspect these first.