30fed66616
Trailing `args: ..T` on a #foreign declaration now lowers to the C calling convention's `...` instead of sx-side slice-packing. Drops the per-arity #foreign-shim workaround for callers of variadic C APIs (__android_log_print, printf-family, etc.). Closes issue-0043. - IR: Function.is_variadic on inst.Function; declareFunction drops the variadic param from the IR signature for foreign+variadic decls. - emit_llvm: LLVMFunctionType receives is_var_arg=1 when the flag is set; call lowering passes extras through unchanged. - Lowering: packVariadicCallArgs early-outs for foreign+variadic (no slice-pack); new promoteCVariadicArgs applies C default argument promotion (bool/s8/s16/u8/u16 -> s32, f32 -> f64) to extras past the fixed param count. - Test: examples/ffi-foreign-cvariadic.sx + .c exercise s64/f64/s32 returns through C va_arg over s32/f64/*u8 element types. 134 host + 6 cross tests pass on the WIP-less baseline.
29 lines
1.0 KiB
Plaintext
29 lines
1.0 KiB
Plaintext
// `#foreign` C-variadic tail: trailing `args: ..T` on a foreign fn maps
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// to the C calling convention's `...`. Extras at the call site are
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// passed via the variadic slot with the standard default argument
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// promotion (s8/s16/bool → s32, f32 → f64) applied implicitly.
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#import "modules/std.sx";
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#import c {
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#source "ffi-foreign-cvariadic.c";
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};
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sx_ffi_sum_ints :: (n: s32, args: ..s32) -> s64 #foreign;
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sx_ffi_avg_doubles :: (n: s32, args: ..f64) -> f64 #foreign;
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sx_ffi_count_args :: (tag: *u8, args: ..*u8) -> s32 #foreign;
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main :: () -> s32 {
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print("sum_ints(3, 10, 20, 30) = {}\n", sx_ffi_sum_ints(3, 10, 20, 30));
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print("sum_ints(0) = {}\n", sx_ffi_sum_ints(0));
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print("avg_doubles(2) = {}\n", sx_ffi_avg_doubles(2, 1.5, 2.5));
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print("avg_doubles(3) = {}\n", sx_ffi_avg_doubles(3, 1.0, 2.0, 3.0));
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a := "alpha".ptr;
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b := "beta".ptr;
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g := "gamma".ptr;
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sentinel : *u8 = null;
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print("count_args(3 strs) = {}\n", sx_ffi_count_args("tag".ptr, a, b, g, sentinel));
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0;
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}
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