f886d5f1be
Passing a default-conv sx function to a `callconv(.c)` fn-pointer slot (e.g. pthread_create's start routine) used to silently mismatch ABIs: the C-side caller didn't supply __sx_ctx, so the sx-side body read its first user param as garbage. The bug surfaced as a SIGSEGV inside ANativeWindow_setBuffersGeometry on Android during chess bringup. Now the compiler rejects the coercion outright at the bare-fn name lookup site: error: call-convention mismatch: 'sx_handler' is declared with default sx convention but the target type expects callconv(.c) Also: `#foreign` declarations without an explicit `callconv` now default to `.c` instead of `.default`. Every external C symbol is by definition C-conv; the previous default silently typed `objc_msgSend` (et al.) as default-conv, so the check would fire on the consumer side when the user typed a fn-ptr as `callconv(.c)`. With the foreign-default fix, the existing typed-msgSend casts in `std/objc.sx` and `gpu/metal.sx` keep type-checking and the rule is "C-conv on both sides or neither." Caught by the new check (fixed in the same commit): - `ios_gl_proc` in `platform/uikit.sx` lacked callconv(.c) but was passed to `load_gl` whose `get_proc` slot expects it. - `ffi_apply_callback` / `ffi_apply_callback2` in `examples/ffi-06-callback.sx` had default-conv fn-ptr params but the C bodies (in the companion .c) are unambiguously C-conv. Regression test: `examples/131-callconv-mismatch-diagnostic.sx` locks in the diagnostic shape (sx-conv fn → callconv(.c) slot). 153/153 example tests pass. Chess green on macOS / iOS sim / Android.
60 lines
2.1 KiB
Plaintext
60 lines
2.1 KiB
Plaintext
// Phase 0 baseline (PLAN-FFI.md step 0.6): sx function passed to C
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// as a function pointer; C invokes it; sx-side observable effect.
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// Mirrors the `app->onInputEvent` install pattern in
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// library/modules/platform/android.sx.
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//
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// Two arities covered:
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// 1. (s32) -> s32 — single-arg callback
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// 2. (*void, s32) -> s32 — pointer + value (onInputEvent shape)
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//
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// Plus a side-effect via a global so we can confirm the callback
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// actually fired (return value + state mutation both observable).
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#import "modules/std.sx";
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#import c {
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#source "ffi-06-callback.c";
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};
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ffi_apply_callback :: (cb: (s32) -> s32 callconv(.c), value: s32) -> s32 #foreign;
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ffi_apply_callback2 :: (cb: (*void, s32) -> s32 callconv(.c), ctx: *void, v: s32) -> s32 #foreign;
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g_callback_hits : s32 = 0;
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g_callback_sum : s32 = 0;
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double_it :: (x: s32) -> s32 callconv(.c) {
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g_callback_hits += 1;
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g_callback_sum += x;
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x * 2;
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}
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add_with_ctx :: (ctx: *void, v: s32) -> s32 callconv(.c) {
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g_callback_hits += 1;
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// Pass a sentinel via ctx to prove the pointer arg also survives the
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// round-trip — read it back as an s32 through *s32.
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p : *s32 = xx ctx;
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p.* + v;
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}
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main :: () -> s32 {
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// ── Single-arg callback ────────────────────────────────────────
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r1 := ffi_apply_callback(double_it, 21);
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print("callback returned = {}\n", r1);
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print("hits after first call = {}\n", g_callback_hits);
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print("sum after first call = {}\n", g_callback_sum);
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// Two more calls confirm the same fn pointer keeps working.
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ffi_apply_callback(double_it, 7);
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ffi_apply_callback(double_it, 11);
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print("hits after three calls = {}\n", g_callback_hits);
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print("sum after three calls = {}\n", g_callback_sum);
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// ── Two-arg callback with opaque ctx pointer ───────────────────
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ctx_val : s32 = 100;
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r2 := ffi_apply_callback2(add_with_ctx, xx @ctx_val, 42);
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print("ctx + value = {}\n", r2);
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print("hits after ctx callback = {}\n", g_callback_hits);
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0;
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}
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