Merge tag 'debian/1.52.1+dfsg1-1_exp2' into proxmox/buster

[rustc.git] / src / test / run-make-fulldeps / c-unwind-abi-catch-panic / main.rs

diff --git a/src/test/run-make-fulldeps/c-unwind-abi-catch-panic/main.rs b/src/test/run-make-fulldeps/c-unwind-abi-catch-panic/main.rs
new file mode 100644 (file)
index 0000000..15d38d7
--- /dev/null
+++ b/src/test/run-make-fulldeps/c-unwind-abi-catch-panic/main.rs
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+//! A test for calling `C-unwind` functions across foreign function boundaries.
+//!
+//! This test triggers a panic when calling a foreign function that calls *back* into Rust.
+#![feature(c_unwind)]
+
+use std::panic::{catch_unwind, AssertUnwindSafe};
+
+fn main() {
+    // Call `add_small_numbers`, passing arguments that will NOT trigger a panic.
+    let (a, b) = (9, 1);
+    let c = unsafe { add_small_numbers(a, b) };
+    assert_eq!(c, 10);
+
+    // Call `add_small_numbers`, passing arguments that will trigger a panic, and catch it.
+    let caught_unwind = catch_unwind(AssertUnwindSafe(|| {
+        let (a, b) = (10, 1);
+        let _c = unsafe { add_small_numbers(a, b) };
+        unreachable!("should have unwound instead of returned");
+    }));
+
+    // Assert that we did indeed panic, then unwrap and downcast the panic into the sum.
+    assert!(caught_unwind.is_err());
+    let panic_obj = caught_unwind.unwrap_err();
+    let msg = panic_obj.downcast_ref::<String>().unwrap();
+    assert_eq!(msg, "11");
+}
+
+#[link(name = "add", kind = "static")]
+extern "C-unwind" {
+    /// An external function, defined in C.
+    ///
+    /// Returns the sum of two numbers, or panics if the sum is greater than 10.
+    fn add_small_numbers(a: u32, b: u32) -> u32;
+}
+
+/// This function will panic if `x` is greater than 10.
+///
+/// This function is called by `add_small_numbers`.
+#[no_mangle]
+pub extern "C-unwind" fn panic_if_greater_than_10(x: u32) {
+    if x > 10 {
+        panic!("{}", x); // That is too big!
+    }
+}