1 files changed, 72 insertions, 0 deletions
diff --git a/tests/codegen/c-variadic.rs b/tests/codegen/c-variadic.rs
new file mode 100644
index 000000000..cab326522
--- /dev/null
+++ b/tests/codegen/c-variadic.rs
@@ -0,0 +1,72 @@
+// ignore-wasm32-bare compiled with panic=abort by default
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
+//
+
+#![crate_type = "lib"]
+#![feature(c_variadic)]
+#![feature(c_unwind)]
+#![no_std]
+use core::ffi::VaList;
+
+extern "C" {
+    fn foreign_c_variadic_0(_: i32, ...);
+    fn foreign_c_variadic_1(_: VaList, ...);
+}
+
+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 we do not remove the `va_list` passed to the foreign function when
+// removing the "spoofed" `VaListImpl` that is used by Rust defined C-variadics.
+pub unsafe extern "C" fn use_foreign_c_variadic_1_0(ap: VaList) {
+    // CHECK: call void ({{.*}}, ...) @foreign_c_variadic_1({{.*}} %ap)
+    foreign_c_variadic_1(ap);
+}
+
+pub unsafe extern "C" fn use_foreign_c_variadic_1_1(ap: VaList) {
+    // CHECK: call void ({{.*}}, ...) @foreign_c_variadic_1({{.*}} %ap, [[PARAM]] 42)
+    foreign_c_variadic_1(ap, 42i32);
+}
+pub unsafe extern "C" fn use_foreign_c_variadic_1_2(ap: VaList) {
+    // CHECK: call void ({{.*}}, ...) @foreign_c_variadic_1({{.*}} %ap, [[PARAM]] 2, [[PARAM]] 42)
+    foreign_c_variadic_1(ap, 2i32, 42i32);
+}
+
+pub unsafe extern "C" fn use_foreign_c_variadic_1_3(ap: VaList) {
+    // CHECK: call void ({{.*}}, ...) @foreign_c_variadic_1({{.*}} %ap, [[PARAM]] 2, [[PARAM]] 42, [[PARAM]] 0)
+    foreign_c_variadic_1(ap, 2i32, 42i32, 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.arg::<i32>();
+    }
+    sum
+    // CHECK: 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);
+}