erlang: 10b progress — 8/18 handlers real (hot-BIFs done) + log

plans/erlang-on-sx.md

@@ -145,7 +145,7 @@ Replace today's hardcoded BIF dispatch (`er-apply-bif`/`er-apply-remote-bif` in
 The Phase 9 opcodes are registered, tested, and bridged SX↔OCaml, but inert: nothing emits them. Phase 10 makes the speedup real.
 
 - [ ] **10a — compiler emits `erlang.OP_*` at hot sites**: teach the Erlang transpiler / `lib/compiler.sx` to emit `erlang.OP_PATTERN_TUPLE` etc. (resolved via `extension-opcode-id`) for hot `case`/`receive`/BIF call sites instead of generic dispatch. **Note:** Erlang currently runs as a pure tree-walking interpreter (`er-eval-expr` over the CEK machine) — there is no Erlang→bytecode path at all. This is a large standalone effort (build an Erlang codegen, or have `lib/compiler.sx` recognize Erlang runtime-helper call sites). Vertical slice de-risked first (see 10b).
-- [~] **10b — real `erlang_ext.ml` handlers** — **vertical slice landed**: `erlang.OP_BIF_LENGTH` (230) is a real register-machine handler (pops an Erlang cons-list off the VM stack, walks `tag`=cons/nil, pushes `Integer` length). End-to-end run_tests proof: bytecode `[CONST 0; 230; RETURN]` with `[1,2,3]` in the constant pool → `Integer 3`, exercising extension-opcode-id → Sx_vm dispatch fallthrough → erlang_ext handler → correct stack result. The other 17 opcodes still `not_wired` (honest raise). Remaining 10b work: real handlers for the other 17 (pattern match, perform/handle, receive-scan, spawn/send, remaining hot BIFs). **+1 run_tests test** (real length) + retained not-wired guard (switched to 231). 715/715 conformance unaffected.
+- [~] **10b — real `erlang_ext.ml` handlers** — **8 of 18 real** (all hot-BIFs done). Real register-machine handlers: `OP_BIF_LENGTH` (230, cons-walk), `OP_BIF_HD` (231), `OP_BIF_TL` (232), `OP_BIF_TUPLE_SIZE` (234, handles List + ListRef `:elements`), `OP_BIF_IS_INTEGER` (236, `Integer _`), `OP_BIF_IS_ATOM` (237), `OP_BIF_IS_LIST` (238, cons|nil), `OP_BIF_IS_TUPLE` (239) — all operate on the tagged-Dict value repr, push Erlang bool atoms via a `mk_atom` helper, raise on type errors. **15 end-to-end run_tests tests** (build real bytecode `[CONST i; op; RETURN]` with list/tuple/atom constants, assert via `Sx_vm.execute_module`). Still `not_wired`: the 8 control opcodes — `OP_PATTERN_TUPLE/LIST/BINARY` (222-224), `OP_PERFORM/HANDLE` (225-226), `OP_RECEIVE_SCAN` (227), `OP_SPAWN/SEND` (228-229) — plus `OP_BIF_ELEMENT` (233, needs 2 operands) and `OP_BIF_LISTS_REVERSE` (235). not-wired guard repointed to 233. 715/715 conformance unaffected (VM-bytecode path only; interpreter untouched). Remaining 10b: the 10 control/structural handlers.
 - [ ] **10c — perf validation**: re-run `bench_ring.sh`; target 100k+ hops/sec at N=1000, 1M-process spawn < 30s; record in `bench_ring_results.md`. Conformance must stay green.
 
 **Acceptance:** ring benchmark hits the 100k hops/sec target. All prior phase tests pass. Two opcodes chiselled to `lib/guest/vm/` (or annotated as candidates with a written rationale).
@@ -154,6 +154,8 @@ The Phase 9 opcodes are registered, tested, and bridged SX↔OCaml, but inert: n
 
 _Newest first._
 
+- **2026-05-15 Phase 10b — all 8 hot-BIF handlers real** — Built on the vertical slice: added 7 more real register-machine handlers in `erlang_ext.ml` (HD 231, TL 232, TUPLE_SIZE 234, IS_INTEGER 236, IS_ATOM 237, IS_LIST 238, IS_TUPLE 239), joining LENGTH 230. Shared helpers added: `mk_atom` (builds the Erlang bool atom `{tag→atom, name→true|false}`), `er_bool`, `is_tag` (Dict tag predicate). TUPLE_SIZE handles both `List` and `ListRef` `:elements` (Erlang tuples may be built mutably). IS_INTEGER keys off `Sx_types.Integer`. All raise descriptive `Eval_error` on type mismatch. The `op N "name"` stub helper now only covers the 10 remaining control/structural opcodes. 9 new end-to-end run_tests assertions added (HD, TL∘HD, TUPLE_SIZE, IS_INTEGER pos+neg, IS_ATOM, IS_LIST nil-true + tuple-false, IS_TUPLE) — each builds real bytecode with a list/tuple/atom constant and executes via `Sx_vm.execute_module`. erlang_ext suite 6→15 PASS; dispatch_count 12. not-wired guard repointed 231→233 (OP_BIF_ELEMENT, still stubbed — it needs two operands so it's a later sub-step). Erlang conformance **715/715** (the interpreter path is untouched; only the VM-bytecode dispatch gained real handlers). Remaining 10b: pattern tuple/list/binary, perform/handle, receive-scan, spawn/send, element, lists:reverse (10 opcodes).
+
 - **2026-05-15 Phase 10b vertical slice — first real opcode handler, end-to-end VM proof** — Investigation first: confirmed Erlang runs as a pure tree-walking interpreter (`er-eval-expr` over CEK) — there is **no** Erlang→bytecode compiler, so full 10a (compiler emits opcodes) is a multi-week standalone effort, not one iteration. Rather than fake it, de-risked the whole Phase 9/10 architecture with a vertical slice: replaced the `not_wired` raise for `erlang.OP_BIF_LENGTH` (id 230) with a genuine register-machine handler in `erlang_ext.ml` — pops a value, walks the Erlang cons-list representation (`Dict` with `"tag"`→`"cons"`/`"nil"`, `"head"`, `"tail"`), pushes `Integer` length, raises on improper lists. Added an end-to-end run_tests test that builds real bytecode `[| 1; 0; 0; 230; 50 |]` (CONST idx 0 → OP_BIF_LENGTH → RETURN) with an Erlang `[1,2,3]` in `vc_constants`, executes via `Sx_vm.execute_module`, asserts `Integer 3`. This proves the complete path works: `extension-opcode-id` → bytecode → `Sx_vm` ≥200 dispatch fallthrough → `erlang_ext` handler → correct VM stack result — the load-bearing proof that Phase 9's wiring isn't just stubs. The other 17 opcodes still honestly raise `not_wired`; the prior not-wired guard test was repointed from 230 to 231 (OP_BIF_HD) so it still verifies the honest-failure path. erlang_ext suite 5→6 tests, dispatch_count now 2. Erlang conformance **715/715** unaffected (the new path is VM-bytecode-only; the interpreter path is untouched). 10b marked in-progress `[~]`; remaining: real handlers for the other 17 opcodes + 10a compiler emission. Builds clean via `dune build bin/run_tests.exe bin/sx_server.exe`.
 
 - **2026-05-15 Phase 9g — perf bench recorded on integrated binary; Phase 10 scoped** — Built the fresh `sx_server.exe` (9a+9h+9i wired in), ran `lib/erlang/bench_ring.sh 10 100 500 1000`: 11/36/35/31 hops/s — statistically identical to the pre-9a baseline (11/24/26/29/34). This is the *expected* outcome and the iteration's actual deliverable: it proves the entire extension stack (vm-ext A-E cherry-pick + `Sx_vm_extensions` force-link + `erlang_ext.ml` + SX dispatcher bridge) added **zero per-hop overhead** — a clean no-regression result — while honestly showing the speedup hasn't arrived because the bytecode compiler still doesn't emit `erlang.OP_*` (every hop takes the general CEK path). Updated `bench_ring_results.md` with a "Phase 9g" section: the table + the rationale that unchanged numbers = correct + no-regression. Conformance **715/715** on the integrated binary. Added **Phase 10 — bytecode emission** to the roadmap (10a compiler emits opcodes at hot sites, 10b real register-machine `erlang_ext.ml` handlers replacing the not-wired raises, 10c perf validation against the 100k-hops/1M-spawn targets). Phase 9 is now fully ticked (9a-9i); the actual speedup is honestly deferred to Phase 10 rather than faked. No code change this iteration — measurement + documentation + roadmap.