`#jni_call` collapses to a single surface — env is *always* implicit:
either picked up from the lexically-enclosing `#jni_env(env) { ... }`
block's Ref (cheap, register-resident, no TL touch) or from the
runtime's thread-local slot via `sx_jni_env_tl_get()` (one fn call
per dispatch). The explicit-env shape is gone — chess and the
existing tests migrate cleanly by wrapping their helper-fn bodies
in `#jni_env(env) { ... }`.
The TL slot lives outside the user's IR module so the LLVM ORC JIT
can load object files cleanly without `orc_rt` for TLS support:
library/vendors/sx_jni_runtime/sx_jni_env_tl.c:
static _Thread_local void *sx_jni_env_tl_slot;
void *sx_jni_env_tl_get(void) { return sx_jni_env_tl_slot; }
void sx_jni_env_tl_set(void *env) { sx_jni_env_tl_slot = env; }
Linkage:
- sx-the-compiler links the .c file via build.zig so the JIT
process-symbol generator resolves `sx_jni_env_tl_get`/`_set`.
- AOT targets get the same .c file auto-linked via the lowering
pass: when lower touches the TL externs, it sets
`needs_jni_env_tl_runtime`, and `Compilation.lowerToIR` appends a
synthetic `CImportInfo` to `lowering_extra_c_sources` that
`collectCImportSources` merges with user-written ones.
Lowering-side changes:
- `getJniEnvTlFids` lazily declares the two externs (parallel
to `getSelRegisterNameFid`) and flips `needs_jni_env_tl_runtime`.
- `#jni_env(env) { body }` emits save→set→body→restore via three
`call` ops to the externs; the inner body sees env via the
lexical-direct stack.
- `lowerJniCall` resolves env from `jni_env_stack` (top) or the TL
fallback. The explicit-env branch is gone.
- `jni_env_stack_base` tracks per-fn lexical scope so lazy-lowering
a callee doesn't accidentally see the caller's Ref (Refs are only
valid inside one fn's instruction stream).
Test migration (mechanical):
- ffi-jni-call-{01..09}: each helper fn wraps `#jni_call(...)`
bodies in `#jni_env(env) { ... }`. Returning values pass through
the block as an expression — `#jni_env` now also lowers in
expression position.
Verified:
- zig build test + tests/run_examples.sh: 130/130 green.
- tests/cross_compile.sh: 3/3 green.
- Chess APK rebuilt + reinstalled on Pixel. Board renders with
status-bar clearance + info panel intact; no crashes in logcat.
Safe-insets dispatch through `#jni_env` + lexical-direct now
fully exercised end-to-end on real hardware.
`Lowering` gains a `jni_env_stack: ArrayList(Ref)`. When lowering
the `jni_env_block` arm pushes the env_expr's Ref before lowering
the body and pops after; `defer` ensures cleanup on early return.
`lowerJniCall` now disambiguates explicit-vs-omitted env via the
position of the first string-literal arg: at index 1 → omitted
(3-arg form `target, "name", "sig"`), at index 2 → explicit
(4-arg form `env, target, "name", "sig"`). Omitted form reads the
top of `jni_env_stack`; missing scope → diagnostic.
End-to-end test runs cleanly. Locked-in IR snapshot at
`tests/expected/ffi-jni-env-02-lexical-direct.ir` shows env coming
from the enclosing fn's `*void` param straight into the jni_msg_send
expansion — no extra load, no thread-local read. The hot-path
optimisation from the design discussion is now real.
128/128 examples + 1 new IR snapshot green; zig test clean.
