[gcc r14-7831] gccrs: [E0045] Variadic Parameters Used on Non-C ABI Function

[gcc r14-7831] gccrs: [E0045] Variadic Parameters Used on Non-C ABI Function

[Arthur Cohen]

https://gcc.gnu.org/g:da58dc1a33dea1fea05636003118ef8d50fdb5f7

commit r14-7831-gda58dc1a33dea1fea05636003118ef8d50fdb5f7
Author: Muhammad Mahad <mahadtxt@gmail.com>
Date:   Wed Jul 19 15:49:25 2023 +0500

    gccrs: [E0045] Variadic Parameters Used on Non-C ABI Function
    
    Added error code support for using variadic parameters used
    on Non-C ABI function. Fixes #2382
    
    gcc/rust/ChangeLog:
    
            * typecheck/rust-hir-type-check-implitem.cc (TypeCheckTopLevelExternItem::visit):
            Added check for error code support.
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/abi-vardaic.rs: New test.
    
    Signed-off-by: Muhammad Mahad <mahadtxt@gmail.com>

Diff:
---
 gcc/rust/typecheck/rust-hir-type-check-implitem.cc | 10 +++++++++-
 gcc/testsuite/rust/compile/abi-vardaic.rs          |  7 +++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/gcc/rust/typecheck/rust-hir-type-check-implitem.cc b/gcc/rust/typecheck/rust-hir-type-check-implitem.cc
index 189dd8797d1..92868b9e343 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-implitem.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-implitem.cc
@@ -138,7 +138,15 @@ TypeCheckTopLevelExternItem::visit (HIR::ExternalFunctionItem &function)
 
   uint8_t flags = TyTy::FnType::FNTYPE_IS_EXTERN_FLAG;
   if (function.is_variadic ())
-    flags |= TyTy::FnType::FNTYPE_IS_VARADIC_FLAG;
+    {
+      flags |= TyTy::FnType::FNTYPE_IS_VARADIC_FLAG;
+      if (parent.get_abi () != Rust::ABI::C)
+	{
+	  rust_error_at (
+	    function.get_locus (), ErrorCode ("E0045"),
+	    "C-variadic function must have C or cdecl calling convention");
+	}
+    }
 
   RustIdent ident{
     CanonicalPath::new_seg (function.get_mappings ().get_nodeid (),
diff --git a/gcc/testsuite/rust/compile/abi-vardaic.rs b/gcc/testsuite/rust/compile/abi-vardaic.rs
new file mode 100644
index 00000000000..b5e0c9a9eff
--- /dev/null
+++ b/gcc/testsuite/rust/compile/abi-vardaic.rs
@@ -0,0 +1,7 @@
+// https://doc.rust-lang.org/error_codes/E0045.html
+#![allow(unused)]
+fn main() {
+    extern "Rust" {
+        fn foo(x: u8, ...); // { dg-error "C-variadic function must have C or cdecl calling convention" }
+    }
+}
\ No newline at end of file