// Phase 1 step 1.8 (PLAN-FFI.md): >16 B non-HFA struct returns
// through `#objc_call`. AAPCS64 routes these through the indirect-
// return convention: caller allocates the result slot, passes its
// pointer as a hidden `x8` arg with the `sret(<T>)` attribute,
// callee writes through it and returns void.
//
// 1.6's `objc_msg_send` lowering hands the IR struct type straight
// to LLVMBuildCall2 — works for ≤16 B aggregates and HFAs of any
// size (since those stay register-resident) but breaks >16 B int
// aggregates: LLVM accepts the signature but the AArch64 backend
// expects the result in x0/x1, the runtime stub doesn't populate
// those for sret-shaped returns, and the upper fields come back
// as garbage.
//
// 1.8a (this commit): xfail. Snapshot shows garbage in the third
// field — pins the broken behavior.
// 1.8b (next commit): emit_llvm.zig applies the sret transform
// (ret type collapses to void, prepend ptr sret param, alloca
// slot at call site, load result post-call) for non-HFA >16 B
// returns. Snapshot flips to all-zeros (Obj-C runtime contract).

#import "modules/std.sx";
#import "modules/compiler.sx";

// 24 B non-HFA integer aggregate. Distinct from any HFA path —
// no all-float / all-double check fires.
Triple :: struct { a: s64; b: s64; c: s64; }

main :: () -> s32 {
    inline if OS == .macos {
        t := #objc_call(Triple)(null, "tripleValue");
        // Per the [nil structReturn] = 0 contract, all three fields
        // should be 0 after 1.8b lands. Today: a/b correct, c is
        // whatever the callee-saves left in the high register.
        print("triple = ({}, {}, {})\n", t.a, t.b, t.c);
    }
    inline if OS != .macos {
        print("skipped (not macos)\n");
    }
    0;
}