rename PointerKind::Shared → SharedMutable to indicate this is NOT the usual shared...

[rust.git] / compiler / rustc_target / src / abi / mod.rs

diff --git a/compiler/rustc_target/src/abi/mod.rs b/compiler/rustc_target/src/abi/mod.rs
index d1eafd6ac5fb82313977fc9ae4224447dbe2c139..b8398daadf1474674bbf3689cffa79db030b9309 100644 (file)
--- a/compiler/rustc_target/src/abi/mod.rs
+++ b/compiler/rustc_target/src/abi/mod.rs
@@ -1350,7 +1350,7 @@ fn deref(&self) -> &&'a LayoutS<'a> {
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
 pub enum PointerKind {
     /// Most general case, we know no restrictions to tell LLVM.
-    Shared,
+    SharedMutable,
 
     /// `&T` where `T` contains no `UnsafeCell`, is `noalias` and `readonly`.
     Frozen,
@@ -1372,7 +1372,7 @@ pub struct PointeeInfo {
 
 /// Used in `might_permit_raw_init` to indicate the kind of initialisation
 /// that is checked to be valid
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum InitKind {
     Zero,
     Uninit,
@@ -1487,14 +1487,18 @@ pub fn is_zst(&self) -> bool {
     ///
     /// `init_kind` indicates if the memory is zero-initialized or left uninitialized.
     ///
-    /// `strict` is an opt-in debugging flag added in #97323 that enables more checks.
+    /// This code is intentionally conservative, and will not detect
+    /// * zero init of an enum whose 0 variant does not allow zero initialization
+    /// * making uninitialized types who have a full valid range (ints, floats, raw pointers)
+    /// * Any form of invalid value being made inside an array (unless the value is uninhabited)
     ///
-    /// This is conservative: in doubt, it will answer `true`.
+    /// A strict form of these checks that uses const evaluation exists in
+    /// `rustc_const_eval::might_permit_raw_init`, and a tracking issue for making these checks
+    /// stricter is <https://github.com/rust-lang/rust/issues/66151>.
     ///
-    /// FIXME: Once we removed all the conservatism, we could alternatively
-    /// create an all-0/all-undef constant and run the const value validator to see if
-    /// this is a valid value for the given type.
-    pub fn might_permit_raw_init<C>(self, cx: &C, init_kind: InitKind, strict: bool) -> bool
+    /// FIXME: Once all the conservatism is removed from here, and the checks are ran by default,
+    /// we can use the const evaluation checks always instead.
+    pub fn might_permit_raw_init<C>(self, cx: &C, init_kind: InitKind) -> bool
     where
         Self: Copy,
         Ty: TyAbiInterface<'a, C>,
@@ -1507,13 +1511,8 @@ pub fn might_permit_raw_init<C>(self, cx: &C, init_kind: InitKind, strict: bool)
                     s.valid_range(cx).contains(0)
                 }
                 InitKind::Uninit => {
-                    if strict {
-                        // The type must be allowed to be uninit (which means "is a union").
-                        s.is_uninit_valid()
-                    } else {
-                        // The range must include all values.
-                        s.is_always_valid(cx)
-                    }
+                    // The range must include all values.
+                    s.is_always_valid(cx)
                 }
             }
         };
@@ -1534,19 +1533,12 @@ pub fn might_permit_raw_init<C>(self, cx: &C, init_kind: InitKind, strict: bool)
         // If we have not found an error yet, we need to recursively descend into fields.
         match &self.fields {
             FieldsShape::Primitive | FieldsShape::Union { .. } => {}
-            FieldsShape::Array { count, .. } => {
+            FieldsShape::Array { .. } => {
                 // FIXME(#66151): For now, we are conservative and do not check arrays by default.
-                if strict
-                    && *count > 0
-                    && !self.field(cx, 0).might_permit_raw_init(cx, init_kind, strict)
-                {
-                    // Found non empty array with a type that is unhappy about this kind of initialization
-                    return false;
-                }
             }
             FieldsShape::Arbitrary { offsets, .. } => {
                 for idx in 0..offsets.len() {
-                    if !self.field(cx, idx).might_permit_raw_init(cx, init_kind, strict) {
+                    if !self.field(cx, idx).might_permit_raw_init(cx, init_kind) {
                         // We found a field that is unhappy with this kind of initialization.
                         return false;
                     }