tweak names and output and bless

Author: RalfJung

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -167,7 +167,7 @@ pub(crate) fn codegen_const_value<'tcx>(
     }
 
     match const_val {
-        ConstValue::Zst => unreachable!(), // we already handles ZST above
+        ConstValue::ZeroSized => unreachable!(), // we already handles ZST above
         ConstValue::Scalar(x) => match x {
             Scalar::Int(int) => {
                 if fx.clif_type(layout.ty).is_some() {

compiler/rustc_codegen_ssa/src/mir/operand.rs

@@ -84,7 +84,7 @@ impl<'a, 'tcx, V: CodegenObject> OperandRef<'tcx, V> {
                 let llval = bx.scalar_to_backend(x, scalar, bx.immediate_backend_type(layout));
                 OperandValue::Immediate(llval)
             }
-            ConstValue::Zst => {
+            ConstValue::ZeroSized => {
                 let llval = bx.zst_to_backend(bx.immediate_backend_type(layout));
                 OperandValue::Immediate(llval)
             }

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -157,7 +157,7 @@ pub(super) fn op_to_const<'tcx>(
                     "this MPlaceTy must come from a validated constant, thus we can assume the \
                 alignment is correct",
                 );
-                ConstValue::Zst
+                ConstValue::ZeroSized
             }
         }
     };

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -272,7 +272,7 @@ pub fn valtree_to_const_value<'tcx>(
     match ty.kind() {
         ty::FnDef(..) => {
             assert!(valtree.unwrap_branch().is_empty());
-            ConstValue::Zst
+            ConstValue::ZeroSized
         }
         ty::Bool | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Char => match valtree {
             ty::ValTree::Leaf(scalar_int) => ConstValue::Scalar(Scalar::Int(scalar_int)),

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -709,7 +709,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 Operand::Indirect(MemPlace::from_ptr(ptr.into()))
             }
             ConstValue::Scalar(x) => Operand::Immediate(tag_scalar(x)?.into()),
-            ConstValue::Zst => Operand::Immediate(Immediate::Uninit),
+            ConstValue::ZeroSized => Operand::Immediate(Immediate::Uninit),
             ConstValue::Slice { data, start, end } => {
                 // We rely on mutability being set correctly in `data` to prevent writes
                 // where none should happen.

compiler/rustc_middle/src/mir/interpret/value.rs

@@ -35,7 +35,7 @@ pub enum ConstValue<'tcx> {
     Scalar(Scalar),
 
     /// Only used for ZSTs.
-    Zst,
+    ZeroSized,
 
     /// Used only for `&[u8]` and `&str`
     Slice { data: ConstAllocation<'tcx>, start: usize, end: usize },
@@ -58,7 +58,7 @@ impl<'a, 'tcx> Lift<'tcx> for ConstValue<'a> {
     fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ConstValue<'tcx>> {
         Some(match self {
             ConstValue::Scalar(s) => ConstValue::Scalar(s),
-            ConstValue::Zst => ConstValue::Zst,
+            ConstValue::ZeroSized => ConstValue::ZeroSized,
             ConstValue::Slice { data, start, end } => {
                 ConstValue::Slice { data: tcx.lift(data)?, start, end }
             }
@@ -73,7 +73,7 @@ impl<'tcx> ConstValue<'tcx> {
     #[inline]
     pub fn try_to_scalar(&self) -> Option<Scalar<AllocId>> {
         match *self {
-            ConstValue::ByRef { .. } | ConstValue::Slice { .. } | ConstValue::Zst => None,
+            ConstValue::ByRef { .. } | ConstValue::Slice { .. } | ConstValue::ZeroSized => None,
             ConstValue::Scalar(val) => Some(val),
         }
     }

compiler/rustc_middle/src/mir/mod.rs

@@ -1711,7 +1711,7 @@ impl<'tcx> Operand<'tcx> {
         Operand::Constant(Box::new(Constant {
             span,
             user_ty: None,
-            literal: ConstantKind::Val(ConstValue::Zst, ty),
+            literal: ConstantKind::Val(ConstValue::ZeroSized, ty),
         }))
     }
 
@@ -2196,7 +2196,7 @@ impl<'tcx> ConstantKind<'tcx> {
 
     #[inline]
     pub fn zero_sized(ty: Ty<'tcx>) -> Self {
-        let cv = ConstValue::Zst;
+        let cv = ConstValue::ZeroSized;
         Self::Val(cv, ty)
     }
 
@@ -2772,6 +2772,13 @@ fn pretty_print_const_value<'tcx>(
                 fmt.write_str(&cx.into_buffer())?;
                 return Ok(());
             }
+            (ConstValue::ZeroSized, ty::FnDef(d, s)) => {
+                let mut cx = FmtPrinter::new(tcx, Namespace::ValueNS);
+                cx.print_alloc_ids = true;
+                let cx = cx.print_value_path(*d, s)?;
+                fmt.write_str(&cx.into_buffer())?;
+                return Ok(());
+            }
             // FIXME(oli-obk): also pretty print arrays and other aggregate constants by reading
             // their fields instead of just dumping the memory.
             _ => {}

compiler/rustc_middle/src/mir/pretty.rs

@@ -448,8 +448,9 @@ impl<'tcx> Visitor<'tcx> for ExtraComments<'tcx> {
                 self.push(&format!("+ user_ty: {:?}", user_ty));
             }
 
+            // FIXME: this is a poor version of `pretty_print_const_value`.
             let fmt_val = |val: &ConstValue<'tcx>| match val {
-                ConstValue::Zst => format!("ZST"),
+                ConstValue::ZeroSized => format!("<ZST>"),
                 ConstValue::Scalar(s) => format!("Scalar({:?})", s),
                 ConstValue::Slice { .. } => format!("Slice(..)"),
                 ConstValue::ByRef { .. } => format!("ByRef(..)"),
@@ -680,7 +681,7 @@ pub fn write_allocations<'tcx>(
             ConstValue::Scalar(interpret::Scalar::Int { .. }) => {
                 Either::Left(Either::Right(std::iter::empty()))
             }
-            ConstValue::Zst => Either::Left(Either::Right(std::iter::empty())),
+            ConstValue::ZeroSized => Either::Left(Either::Right(std::iter::empty())),
             ConstValue::ByRef { alloc, .. } | ConstValue::Slice { data: alloc, .. } => {
                 Either::Right(alloc_ids_from_alloc(alloc))
             }

compiler/rustc_mir_build/src/build/expr/as_constant.rs

@@ -61,7 +61,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                         inferred_ty: ty,
                     })
                 });
-                let literal = ConstantKind::Val(ConstValue::Zst, ty);
+                let literal = ConstantKind::Val(ConstValue::ZeroSized, ty);
 
                 Constant { span, user_ty: user_ty, literal }
             }

src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.32bit.mir

@@ -39,7 +39,7 @@ fn main() -> () {
         _5 = foo(move _6) -> bb1;        // scope 4 at $DIR/array-index-is-temporary.rs:16:21: 16:27
                                          // mir::Constant
                                          // + span: $DIR/array-index-is-temporary.rs:16:21: 16:24
-                                         // + literal: Const { ty: unsafe fn(*mut usize) -> u32 {foo}, val: Value(Scalar(<ZST>)) }
+                                         // + literal: Const { ty: unsafe fn(*mut usize) -> u32 {foo}, val: Value(<ZST>) }
     }
 
     bb1: {