Add the `no-builtins` attribute to functions when `no_builtins` is applied at the crate level.

When `no_builtins` is applied at the crate level, we should add the
`no-builtins` attribute to each function to ensure it takes effect in LTO.

1 files changed, 24 insertions, 0 deletions

diff --git a/tests/codegen/no_builtins-at-crate.rs b/tests/codegen/no_builtins-at-crate.rs
new file mode 100644
index 00000000000..02ed670900e
--- /dev/null
+++ b/tests/codegen/no_builtins-at-crate.rs
@@ -0,0 +1,24 @@
+// compile-flags: -C opt-level=1
+
+#![no_builtins]
+#![crate_type = "lib"]
+
+// CHECK: define
+// CHECK-SAME: @__aeabi_memcpy
+// CHECK-SAME: #0
+#[no_mangle]
+pub unsafe extern "C" fn __aeabi_memcpy(dest: *mut u8, src: *const u8, size: usize) {
+    // CHECK: call
+    // CHECK-SAME: @memcpy(
+    memcpy(dest, src, size);
+}
+
+// CHECK: declare
+// CHECK-SAME: @memcpy
+// CHECK-SAME: #0
+extern "C" {
+    pub fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8;
+}
+
+// CHECK: attributes #0
+// CHECK-SAME: "no-builtins"