Auto merge of #94157 - erikdesjardins:more-noundef, r=nikic

Apply noundef attribute to all scalar types which do not permit raw init

Beyond `&`/`&mut`/`Box`, this covers `char`, enum discriminants, `NonZero*`, etc.
All such types currently cause a Miri error if left uninitialized,
and an `invalid_value` lint in cases like `mem::uninitialized::<char>()`.

Note that this _does not_ change whether or not it is UB for `u64` (or
other integer types with no invalid values) to be undef.

Fixes (partially) #74378.

r? `@ghost` (blocked on #94127)

`@rustbot` label S-blocked

1 files changed, 49 insertions, 1 deletions

diff --git a/src/test/codegen/function-arguments.rs b/src/test/codegen/function-arguments.rs
index 17b54d86cb0..b1ccbdd934a 100644
--- a/src/test/codegen/function-arguments.rs
+++ b/src/test/codegen/function-arguments.rs
@@ -4,6 +4,7 @@
 #![feature(rustc_attrs)]
 
 use std::mem::MaybeUninit;
+use std::num::NonZeroU64;
 
 pub struct S {
   _field: [i32; 8],
@@ -13,6 +14,11 @@ pub struct UnsafeInner {
   _field: std::cell::UnsafeCell<i16>,
 }
 
+pub enum MyBool {
+  True,
+  False,
+}
+
 // CHECK: noundef zeroext i1 @boolean(i1 noundef zeroext %x)
 #[no_mangle]
 pub fn boolean(x: bool) -> bool {
@@ -25,6 +31,48 @@ pub fn maybeuninit_boolean(x: MaybeUninit<bool>) -> MaybeUninit<bool> {
   x
 }
 
+// CHECK: noundef zeroext i1 @enum_bool(i1 noundef zeroext %x)
+#[no_mangle]
+pub fn enum_bool(x: MyBool) -> MyBool {
+  x
+}
+
+// CHECK: i8 @maybeuninit_enum_bool(i8 %x)
+#[no_mangle]
+pub fn maybeuninit_enum_bool(x: MaybeUninit<MyBool>) -> MaybeUninit<MyBool> {
+  x
+}
+
+// CHECK: noundef i32 @char(i32 noundef %x)
+#[no_mangle]
+pub fn char(x: char) -> char {
+  x
+}
+
+// CHECK: i32 @maybeuninit_char(i32 %x)
+#[no_mangle]
+pub fn maybeuninit_char(x: MaybeUninit<char>) -> MaybeUninit<char> {
+  x
+}
+
+// CHECK: i64 @int(i64 %x)
+#[no_mangle]
+pub fn int(x: u64) -> u64 {
+  x
+}
+
+// CHECK: noundef i64 @nonzero_int(i64 noundef %x)
+#[no_mangle]
+pub fn nonzero_int(x: NonZeroU64) -> NonZeroU64 {
+  x
+}
+
+// CHECK: i64 @option_nonzero_int(i64 %x)
+#[no_mangle]
+pub fn option_nonzero_int(x: Option<NonZeroU64>) -> Option<NonZeroU64> {
+  x
+}
+
 // CHECK: @readonly_borrow(i32* noalias noundef readonly align 4 dereferenceable(4) %_1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
@@ -156,7 +204,7 @@ pub fn return_slice(x: &[u16]) -> &[u16] {
   x
 }
 
-// CHECK: { i16, i16 } @enum_id_1(i16 %x.0, i16 %x.1)
+// CHECK: { i16, i16 } @enum_id_1(i16 noundef %x.0, i16 %x.1)
 #[no_mangle]
 pub fn enum_id_1(x: Option<Result<u16, u16>>) -> Option<Result<u16, u16>> {
   x