Auto merge of #105613 - Nilstrieb:rename-assert_uninit_valid, r=RalfJung

Rename `assert_uninit_valid` intrinsic

It's not about "uninit" anymore but about "filling with 0x01 bytes" so the name should at least try to reflect that.

This is actually not fully correct though, as it does still panic for all uninit with `-Zstrict-init-checks`. I'm not sure what the best way is to deal with that not causing confusion. I guess we could just remove the flag? I don't think having it makes a lot of sense anymore with the direction that we have chose to go. It could be relevant again if #100423 lands so removing it may be a bit over eager.

r? `@RalfJung`

9 files changed, 24 insertions, 19 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
index 7a380acf798..e4ac89a7bec 100644
--- a/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/mod.rs
@@ -644,7 +644,7 @@ fn codegen_regular_intrinsic_call<'tcx>(
             let res = CValue::by_val(res, arg.layout());
             ret.write_cvalue(fx, res);
         }
-        sym::assert_inhabited | sym::assert_zero_valid | sym::assert_uninit_valid => {
+        sym::assert_inhabited | sym::assert_zero_valid | sym::assert_mem_uninitialized_valid => {
             intrinsic_args!(fx, args => (); intrinsic);
 
             let layout = fx.layout_of(substs.type_at(0));
@@ -673,7 +673,9 @@ fn codegen_regular_intrinsic_call<'tcx>(
                 return;
             }
 
-            if intrinsic == sym::assert_uninit_valid && !fx.tcx.permits_uninit_init(layout) {
+            if intrinsic == sym::assert_mem_uninitialized_valid
+                && !fx.tcx.permits_uninit_init(layout)
+            {
                 with_no_trimmed_paths!({
                     crate::base::codegen_panic(
                         fx,
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs
index 3860138018b..cff72048ead 100644
--- a/compiler/rustc_codegen_ssa/src/mir/block.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/block.rs
@@ -663,12 +663,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         enum AssertIntrinsic {
             Inhabited,
             ZeroValid,
-            UninitValid,
+            MemUninitializedValid,
         }
         let panic_intrinsic = intrinsic.and_then(|i| match i {
             sym::assert_inhabited => Some(AssertIntrinsic::Inhabited),
             sym::assert_zero_valid => Some(AssertIntrinsic::ZeroValid),
-            sym::assert_uninit_valid => Some(AssertIntrinsic::UninitValid),
+            sym::assert_mem_uninitialized_valid => Some(AssertIntrinsic::MemUninitializedValid),
             _ => None,
         });
         if let Some(intrinsic) = panic_intrinsic {
@@ -679,7 +679,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             let do_panic = match intrinsic {
                 Inhabited => layout.abi.is_uninhabited(),
                 ZeroValid => !bx.tcx().permits_zero_init(layout),
-                UninitValid => !bx.tcx().permits_uninit_init(layout),
+                MemUninitializedValid => !bx.tcx().permits_uninit_init(layout),
             };
             Some(if do_panic {
                 let msg_str = with_no_visible_paths!({
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index 9b56757eb39..d4c99af43c3 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -428,7 +428,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             sym::transmute => {
                 self.copy_op(&args[0], dest, /*allow_transmute*/ true)?;
             }
-            sym::assert_inhabited | sym::assert_zero_valid | sym::assert_uninit_valid => {
+            sym::assert_inhabited
+            | sym::assert_zero_valid
+            | sym::assert_mem_uninitialized_valid => {
                 let ty = instance.substs.type_at(0);
                 let layout = self.layout_of(ty)?;
 
@@ -460,7 +462,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     }
                 }
 
-                if intrinsic_name == sym::assert_uninit_valid {
+                if intrinsic_name == sym::assert_mem_uninitialized_valid {
                     let should_panic = !self.tcx.permits_uninit_init(layout);
 
                     if should_panic {
diff --git a/compiler/rustc_hir_analysis/src/check/intrinsic.rs b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
index 69e54b41d4c..598dc2dca5c 100644
--- a/compiler/rustc_hir_analysis/src/check/intrinsic.rs
+++ b/compiler/rustc_hir_analysis/src/check/intrinsic.rs
@@ -75,7 +75,7 @@ pub fn intrinsic_operation_unsafety(tcx: TyCtxt<'_>, intrinsic_id: DefId) -> hir
         sym::abort
         | sym::assert_inhabited
         | sym::assert_zero_valid
-        | sym::assert_uninit_valid
+        | sym::assert_mem_uninitialized_valid
         | sym::size_of
         | sym::min_align_of
         | sym::needs_drop
@@ -193,9 +193,9 @@ pub fn check_intrinsic_type(tcx: TyCtxt<'_>, it: &hir::ForeignItem<'_>) {
             }
             sym::rustc_peek => (1, vec![param(0)], param(0)),
             sym::caller_location => (0, vec![], tcx.caller_location_ty()),
-            sym::assert_inhabited | sym::assert_zero_valid | sym::assert_uninit_valid => {
-                (1, Vec::new(), tcx.mk_unit())
-            }
+            sym::assert_inhabited
+            | sym::assert_zero_valid
+            | sym::assert_mem_uninitialized_valid => (1, Vec::new(), tcx.mk_unit()),
             sym::forget => (1, vec![param(0)], tcx.mk_unit()),
             sym::transmute => (2, vec![param(0)], param(1)),
             sym::prefetch_read_data
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index f23959b6e47..e8026634713 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -376,9 +376,9 @@ symbols! {
         assert_eq_macro,
         assert_inhabited,
         assert_macro,
+        assert_mem_uninitialized_valid,
         assert_ne_macro,
         assert_receiver_is_total_eq,
-        assert_uninit_valid,
         assert_zero_valid,
         asserting,
         associated_const_equality,
diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 7ed7d767f2f..a521905a9e7 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -959,13 +959,13 @@ extern "rust-intrinsic" {
     #[rustc_safe_intrinsic]
     pub fn assert_zero_valid<T>();
 
-    /// A guard for unsafe functions that cannot ever be executed if `T` has invalid
-    /// bit patterns: This will statically either panic, or do nothing.
+    /// A guard for `std::mem::uninitialized`. This will statically either panic, or do nothing.
     ///
     /// This intrinsic does not have a stable counterpart.
     #[rustc_const_unstable(feature = "const_assert_type2", issue = "none")]
     #[rustc_safe_intrinsic]
-    pub fn assert_uninit_valid<T>();
+    #[cfg(not(bootstrap))]
+    pub fn assert_mem_uninitialized_valid<T>();
 
     /// Gets a reference to a static `Location` indicating where it was called.
     ///
diff --git a/library/core/src/mem/mod.rs b/library/core/src/mem/mod.rs
index 383bdc7b6e2..5e01ccc07d8 100644
--- a/library/core/src/mem/mod.rs
+++ b/library/core/src/mem/mod.rs
@@ -682,7 +682,8 @@ pub unsafe fn zeroed<T>() -> T {
 pub unsafe fn uninitialized<T>() -> T {
     // SAFETY: the caller must guarantee that an uninitialized value is valid for `T`.
     unsafe {
-        intrinsics::assert_uninit_valid::<T>();
+        #[cfg(not(bootstrap))] // If the compiler hits this itself then it deserves the UB.
+        intrinsics::assert_mem_uninitialized_valid::<T>();
         let mut val = MaybeUninit::<T>::uninit();
 
         // Fill memory with 0x01, as an imperfect mitigation for old code that uses this function on
diff --git a/src/test/ui/consts/assert-type-intrinsics.rs b/src/test/ui/consts/assert-type-intrinsics.rs
index 263d1ae6a3e..b4fd423becd 100644
--- a/src/test/ui/consts/assert-type-intrinsics.rs
+++ b/src/test/ui/consts/assert-type-intrinsics.rs
@@ -13,7 +13,7 @@ fn main() {
         //~^ERROR: evaluation of constant value failed
     };
     const _BAD2: () = {
-        intrinsics::assert_uninit_valid::<&'static i32>();
+        intrinsics::assert_mem_uninitialized_valid::<&'static i32>();
         //~^ERROR: evaluation of constant value failed
     };
     const _BAD3: () = {
diff --git a/src/test/ui/consts/assert-type-intrinsics.stderr b/src/test/ui/consts/assert-type-intrinsics.stderr
index f92f9fda069..70aec91e226 100644
--- a/src/test/ui/consts/assert-type-intrinsics.stderr
+++ b/src/test/ui/consts/assert-type-intrinsics.stderr
@@ -7,8 +7,8 @@ LL |         MaybeUninit::<!>::uninit().assume_init();
 error[E0080]: evaluation of constant value failed
   --> $DIR/assert-type-intrinsics.rs:16:9
    |
-LL |         intrinsics::assert_uninit_valid::<&'static i32>();
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to leave type `&i32` uninitialized, which is invalid
+LL |         intrinsics::assert_mem_uninitialized_valid::<&'static i32>();
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ aborted execution: attempted to leave type `&i32` uninitialized, which is invalid
 
 error[E0080]: evaluation of constant value failed
   --> $DIR/assert-type-intrinsics.rs:20:9