tests: Test line number in debuginfo for diverging function calls

tests/codegen/diverging-function-call-debuginfo.rs

@@ -0,0 +1,38 @@
+/// Make sure that line debuginfo is correct for diverging calls under certain
+/// conditions. In particular we want to ensure that the line number is never
+/// 0, but we check the absence of 0 by looking for the expected exact line
+/// numbers. Regression test for <https://github.com/rust-lang/rust/issues/59558>.
+
+//@ compile-flags: -g -Clto -Copt-level=0
+//@ no-prefer-dynamic
+
+// First find the scope of both diverge() calls, namely this main() function.
+// CHECK-DAG: [[MAIN_SCOPE:![0-9]+]] = distinct !DISubprogram(name: "main", linkageName: {{.*}}diverging_function_call_debuginfo{{.*}}main{{.*}}
+fn main() {
+    if True == False {
+        // unreachable
+        // Then find the DILocation with the correct line number for this call ...
+        // CHECK-DAG: [[UNREACHABLE_CALL_DBG:![0-9]+]] = !DILocation(line: [[@LINE+1]], {{.*}}scope: [[MAIN_SCOPE]]
+        diverge();
+    }
+
+    // ... and this call.
+    // CHECK-DAG: [[LAST_CALL_DBG:![0-9]+]] = !DILocation(line: [[@LINE+1]], {{.*}}scope: [[MAIN_SCOPE]]
+    diverge();
+}
+
+#[derive(PartialEq)]
+pub enum MyBool {
+    True,
+    False,
+}
+
+use MyBool::*;
+
+fn diverge() -> ! {
+    panic!();
+}
+
+// Finally make sure both DILocations belong to each the respective diverge() call.
+// CHECK-DAG: call void {{.*}}diverging_function_call_debuginfo{{.*}}diverge{{.*}} !dbg [[LAST_CALL_DBG]]
+// CHECK-DAG: call void {{.*}}diverging_function_call_debuginfo{{.*}}diverge{{.*}} !dbg [[UNREACHABLE_CALL_DBG]]