tests/codegen-llvm/cffi/c-variadic.rs

//@ needs-unwind
//@ compile-flags: -C no-prepopulate-passes -Copt-level=0
// Pauthtest generates pointer authentication metadata for call instructions
// and wraps function pointers in ConstPtrAuth. Disable this test for this target
// to avoid clutter from pointer authentication complexity.
//@ ignore-pauthtest

#![crate_type = "lib"]
#![no_std]
use core::ffi::VaList;

extern "C" {
    fn foreign_c_variadic_0(_: i32, ...);
}

pub unsafe extern "C" fn use_foreign_c_variadic_0() {
    // Ensure that we correctly call foreign C-variadic functions.
    // CHECK: call void (i32, ...) @foreign_c_variadic_0([[PARAM:i32( signext)?]] 0)
    foreign_c_variadic_0(0);
    // CHECK: call void (i32, ...) @foreign_c_variadic_0([[PARAM]] 0, [[PARAM]] 42)
    foreign_c_variadic_0(0, 42i32);
    // CHECK: call void (i32, ...) @foreign_c_variadic_0([[PARAM]] 0, [[PARAM]] 42, [[PARAM]] 1024)
    foreign_c_variadic_0(0, 42i32, 1024i32);
    // CHECK: call void (i32, ...) @foreign_c_variadic_0([[PARAM]] 0, [[PARAM]] 42, [[PARAM]] 1024, [[PARAM]] 0)
    foreign_c_variadic_0(0, 42i32, 1024i32, 0i32);
}

// Ensure that `va_start` and `va_end` are properly injected.
#[no_mangle]
pub unsafe extern "C" fn c_variadic(n: i32, mut ap: ...) -> i32 {
    // CHECK: call void @llvm.va_start
    let mut sum = 0;
    for _ in 0..n {
        sum += ap.next_arg::<i32>();
    }
    sum
    // We no longer call the LLVM va_end.
    // CHECK-NOT: call void @llvm.va_end
}

// Ensure that we generate the correct `call` signature when calling a Rust
// defined C-variadic.
pub unsafe fn test_c_variadic_call() {
    // CHECK: call [[RET:(signext )?i32]] (i32, ...) @c_variadic([[PARAM]] 0)
    c_variadic(0);
    // CHECK: call [[RET]] (i32, ...) @c_variadic([[PARAM]] 0, [[PARAM]] 42)
    c_variadic(0, 42i32);
    // CHECK: call [[RET]] (i32, ...) @c_variadic([[PARAM]] 0, [[PARAM]] 42, [[PARAM]] 1024)
    c_variadic(0, 42i32, 1024i32);
    // CHECK: call [[RET]] (i32, ...) @c_variadic([[PARAM]] 0, [[PARAM]] 42, [[PARAM]] 1024, [[PARAM]] 0)
    c_variadic(0, 42i32, 1024i32, 0i32);
}