1 files changed, 106 insertions, 0 deletions
diff --git a/tests/codegen-llvm/avr/avr-func-addrspace.rs b/tests/codegen-llvm/avr/avr-func-addrspace.rs
new file mode 100644
index 00000000000..e0192f8b45a
--- /dev/null
+++ b/tests/codegen-llvm/avr/avr-func-addrspace.rs
@@ -0,0 +1,106 @@
+//@ add-core-stubs
+//@ compile-flags: -Copt-level=3 --target=avr-none -C target-cpu=atmega328p --crate-type=rlib -C panic=abort
+//@ needs-llvm-components: avr
+
+// This test validates that function pointers can be stored in global variables
+// and called upon. It ensures that Rust emits function pointers in the correct
+// address space to LLVM so that an assertion error relating to casting is
+// not triggered.
+//
+// It also validates that functions can be called through function pointers
+// through traits.
+
+#![feature(no_core, lang_items, intrinsics, unboxed_closures, arbitrary_self_types)]
+#![crate_type = "lib"]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
+
+#[rustc_intrinsic]
+pub unsafe fn transmute<Src, Dst>(src: Src) -> Dst;
+
+pub static mut STORAGE_FOO: fn(&usize, &mut u32) -> Result<(), ()> = arbitrary_black_box;
+pub static mut STORAGE_BAR: u32 = 12;
+
+fn arbitrary_black_box(ptr: &usize, _: &mut u32) -> Result<(), ()> {
+    let raw_ptr = ptr as *const usize;
+    let _v: usize = unsafe { *raw_ptr };
+    loop {}
+}
+
+#[inline(never)]
+#[no_mangle]
+fn call_through_fn_trait(a: &mut impl Fn<(), Output = ()>) {
+    (*a)()
+}
+
+#[inline(never)]
+fn update_bar_value() {
+    unsafe {
+        STORAGE_BAR = 88;
+    }
+}
+
+// CHECK: define dso_local void @test(){{.+}}addrspace(1)
+#[no_mangle]
+pub extern "C" fn test() {
+    let mut buf = 7;
+
+    // A call through the Fn trait must use address space 1.
+    //
+    // CHECK: call{{.+}}addrspace(1) void @call_through_fn_trait({{.*}})
+    call_through_fn_trait(&mut update_bar_value);
+
+    // A call through a global variable must use address space 1.
+    // CHECK: load {{.*}}addrspace(1){{.+}}FOO
+    unsafe {
+        STORAGE_FOO(&1, &mut buf);
+    }
+}
+
+// Validate that we can codegen transmutes between data ptrs and fn ptrs.
+
+// CHECK: define{{.+}}ptr addrspace(1) @transmute_data_ptr_to_fn(ptr{{.*}} %x)
+#[no_mangle]
+pub unsafe fn transmute_data_ptr_to_fn(x: *const ()) -> fn() {
+    // It doesn't matter precisely how this is codegenned (through memory or an addrspacecast),
+    // as long as it doesn't cause a verifier error by using `bitcast`.
+    transmute(x)
+}
+
+// CHECK: define{{.+}}ptr @transmute_fn_ptr_to_data(ptr addrspace(1){{.*}} %x)
+#[no_mangle]
+pub unsafe fn transmute_fn_ptr_to_data(x: fn()) -> *const () {
+    // It doesn't matter precisely how this is codegenned (through memory or an addrspacecast),
+    // as long as it doesn't cause a verifier error by using `bitcast`.
+    transmute(x)
+}
+
+pub enum Either<T, U> {
+    A(T),
+    B(U),
+}
+
+// Previously, we would codegen this as passing/returning a scalar pair of `{ i8, ptr }`,
+// with the `ptr` field representing both `&i32` and `fn()` depending on the variant.
+// This is incorrect, because `fn()` should be `ptr addrspace(1)`, not `ptr`.
+
+// CHECK: define{{.+}}void @should_not_combine_addrspace(ptr{{.+}}sret{{.+}}%_0, ptr{{.+}}%x)
+#[no_mangle]
+#[inline(never)]
+pub fn should_not_combine_addrspace(x: Either<&i32, fn()>) -> Either<&i32, fn()> {
+    x
+}
+
+// The incorrectness described above would result in us producing (after optimizations)
+// a `ptrtoint`/`inttoptr` roundtrip to convert from `ptr` to `ptr addrspace(1)`.
+
+// CHECK-LABEL: @call_with_fn_ptr
+#[no_mangle]
+pub fn call_with_fn_ptr<'a>(f: fn()) -> Either<&'a i32, fn()> {
+    // CHECK-NOT: ptrtoint
+    // CHECK-NOT: inttoptr
+    // CHECK: call addrspace(1) void @should_not_combine_addrspace
+    should_not_combine_addrspace(Either::B(f))
+}