# Session save — 2026-09-25: self-hosting runtime

Started from "the whole compiler source set compiles under V3 and links"
(`v3-selfcompile-image`) and pushed the **runtime** much further.

## Landed

| Tag | What |
|---|---|
| `v3-selfcompile-image` | nested modules (`ListHandler`); `HALT`; `Strings.Delete`/`Append`; 1-char literal to `VAR ARRAY OF CHAR`; nested anonymous-array bound-clobber fix; `sessBuf` 4 MiB + manual flush; `strNams/strTexts` 4096 |
| `v3-inline-array-fields` | record array fields are **inline** (standard M2 layout), not pointers: SymTab layout, QbeGen data/access/copy, `InitHeap` in place, `SymTab` `ALLOCATE`→`NEW` |
| `v3-nul-strings` | **NUL-terminated** CHAR arrays (terminator slot at index = count, index = count readable); stdlib `Strings` and the C shim are NUL-based; `m2arg` keeps capacity |
| `af392e1` | scanner `Reset`: `NEW(buf[i])` (BufBlock needs a descriptor header) |
| `v3-deref-var-actual` | `^` yields the pointee address: `sfx := TRUE`, so a `VAR` actual `p^`/`a[i]^` passes the pointee address (was `AddrOf(base)`) |

Main suite 111/111 throughout.

## Self-compiled compiler status

It now:
1. **runs** (no startup crash — the heap/inline-array fix),
2. **opens its input** via the self-hosted `FileIO` + shim,
3. **starts parsing** — and crashes in the scanner's `Reset`.

### Fixed: `VAR` actual of a dereferenced pointer (`v3-deref-var-actual`)

For a `VAR` actual that is a dereferenced pointer (`b[0]^`), V3 passed
`AddrOf(b)` instead of the pointee address. `Design`'s `^` handler now
always sets `sfx := TRUE` (q holds the pointee address), so Fact's
VAR-actual note is `q` itself. Repro `Fill(b[0]^)` now works; the
scanner's `FileIO.ReadBytes(src, buf[i]^, read)` is correct.

## Current crash

The self-compiled compiler now parses the scanner/parser and reaches the
source's `TYPE` block, then segfaults in `SymTab.OpaqueBase`
(`TypeItem ← TypeBlock ← DeclSeq ← ProgModule`), dereferencing a bad
symbol node (`mov 0x49(%rax),…`). Next runtime bug to chase.

## Remaining after that

- Re-run the self-compiled compiler on a file; iterate on further
  runtime bugs.
- Cross-stage `FileIO` selection and `bootstrap/fixpoint.sh`
  (Stage1 gm2 → Stage2 V3 → Stage3 V3, byte-identical `.ssa`), with the
  stage-aware CR flag (`-m` for gm2, no `-m` for V3).

## Note

`compiler/toto.mod` is the user's uncommitted edit (left alone).