9a2c78d6b9
A trailing `..args: []T` on an `extern` fn must map to the C `...` tail like its `#foreign` twin (example 1218). Today the variadic handling in both declareFunction (is_variadic drop) and packVariadicCallArgs (call-site early-out) is gated on `#foreign` only, so a variadic `extern` keeps the trailing slice param and slice-packs the extras — garbage at the C ABI (probe: sum_ints(3,10,20,30) → 53316585, not 60). Example 1229 pins the DESIRED correct output; the next commit extends both gates to cover extern and greens it. Prerequisite for migrating the fn-decl `#foreign` path onto `extern`. 645 corpus (1229 xfail), 444 unit.
28 lines
1.1 KiB
Plaintext
28 lines
1.1 KiB
Plaintext
// `extern` C-variadic tail: a trailing `..args: []T` on an `extern` fn
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// maps to the C calling convention's `...`, exactly like its `#foreign`
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// twin (example 1218). Extras at the call site pass through the variadic
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// slot with standard default argument promotion (i8/i16/bool → i32,
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// f32 → f64), NOT packed into an sx slice.
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//
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// Regression (FFI-linkage Part B): the `is_variadic` drop in
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// `declareFunction` + the call-site early-out in `packVariadicCallArgs`
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// were gated on `#foreign` only, so a migrated variadic `extern` lost
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// its `...` tail and slice-packed the extras (garbage at the C ABI).
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#import "modules/std.sx";
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#import c {
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#source "1229-ffi-extern-cvariadic.c";
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};
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sx_ext_sum_ints :: (n: i32, ..args: []i32) -> i64 extern;
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sx_ext_avg_doubles :: (n: i32, ..args: []f64) -> f64 extern;
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main :: () -> i32 {
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print("sum_ints(3, 10, 20, 30) = {}\n", sx_ext_sum_ints(3, 10, 20, 30));
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print("sum_ints(0) = {}\n", sx_ext_sum_ints(0));
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print("avg_doubles(2) = {}\n", sx_ext_avg_doubles(2, 1.5, 2.5));
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print("avg_doubles(3) = {}\n", sx_ext_avg_doubles(3, 1.0, 2.0, 3.0));
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0
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}
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