Add large byval align regression

Author: Dnreikronos

build_system/tests.rs

@@ -92,6 +92,40 @@ const BASE_SYSROOT_SUITE: &[TestCase] = &[
     TestCase::build_bin_and_run("aot.neon", "example/neon.rs", &[]),
     TestCase::build_bin_and_run("aot.gen_block_iterate", "example/gen_block_iterate.rs", &[]),
     TestCase::build_bin_and_run("aot.raw-dylib", "example/raw-dylib.rs", &[]),
+    TestCase::custom("aot.large-byval-align", &|runner| {
+        if !runner.target_compiler.triple.starts_with("x86_64-")
+            || runner.target_compiler.triple.contains("windows")
+        {
+            eprintln!(
+                "Skipping large-byval-align: target {} does not hit the backend limit",
+                runner.target_compiler.triple
+            );
+            return;
+        }
+
+        let output = runner
+            .rustc_command(["example/large-byval-align.rs", "--crate-type", "lib", "-Copt-level=0"])
+            .output()
+            .expect("failed to run rustc");
+        assert!(
+            !output.status.success(),
+            "expected large-byval-align.rs to exceed a backend implementation limit"
+        );
+
+        let stderr = String::from_utf8_lossy(&output.stderr);
+        assert!(
+            stderr.contains("backend implementation limit exceeded"),
+            "expected backend implementation limit error, got:\n{stderr}"
+        );
+        assert!(
+            !stderr.contains("internal compiler error"),
+            "backend implementation limit should not ICE:\n{stderr}"
+        );
+        assert!(
+            !stderr.contains("expected abort due to worker thread errors"),
+            "worker thread fatal should be reported through diagnostics:\n{stderr}"
+        );
+    }),
     TestCase::custom("test.sysroot", &|runner| {
         apply_patches(
             &runner.dirs,

config.txt

@@ -24,6 +24,7 @@ aot.issue-59326
 aot.neon
 aot.gen_block_iterate
 aot.raw-dylib
+aot.large-byval-align
 test.sysroot
 
 testsuite.extended_sysroot

example/large-byval-align.rs

@@ -0,0 +1,6 @@
+#[allow(dead_code)]
+#[repr(align(536870912))]
+pub struct A(i64);
+
+#[allow(improper_ctypes_definitions, unused_variables)]
+pub extern "C" fn foo(x: A) {}