Rollup merge of #108029 - oli-obk:🞋_usize, r=RalfJung

s/eval_usize/eval_target_usize/ for clarity

r? `@nnethercote`

as discussed in https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/.60Const.60.20and.20.60usize.60.2F.60u64.60 it is unclear what `usize` means and why we use a `u64` for something talking about `usize`. This renaming should make it clear that we're talking about `usize`s on the target platform, irrespective of the compiler host platform.

7 files changed, 20 insertions, 12 deletions

diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 6f42b69633c..6378ca6e77d 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -2344,9 +2344,13 @@ impl<'tcx> ConstantKind<'tcx> {
     }
 
     #[inline]
-    pub fn try_eval_usize(&self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Option<u64> {
+    pub fn try_eval_target_usize(
+        &self,
+        tcx: TyCtxt<'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+    ) -> Option<u64> {
         match self {
-            Self::Ty(ct) => ct.try_eval_usize(tcx, param_env),
+            Self::Ty(ct) => ct.try_eval_target_usize(tcx, param_env),
             Self::Val(val, _) => val.try_to_machine_usize(tcx),
             Self::Unevaluated(uneval, _) => {
                 match tcx.const_eval_resolve(param_env, *uneval, None) {
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index 9f544de9f87..97dc8a99f9b 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -97,7 +97,7 @@ impl<'tcx> PlaceTy<'tcx> {
                     ty::Slice(..) => self.ty,
                     ty::Array(inner, _) if !from_end => tcx.mk_array(*inner, (to - from) as u64),
                     ty::Array(inner, size) if from_end => {
-                        let size = size.eval_usize(tcx, param_env);
+                        let size = size.eval_target_usize(tcx, param_env);
                         let len = size - (from as u64) - (to as u64);
                         tcx.mk_array(*inner, len)
                     }
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index 65cbac3e8f1..3ad56e8f273 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -175,7 +175,7 @@ impl<'tcx> Const<'tcx> {
 
     #[inline]
     /// Creates an interned usize constant.
-    pub fn from_usize(tcx: TyCtxt<'tcx>, n: u64) -> Self {
+    pub fn from_target_usize(tcx: TyCtxt<'tcx>, n: u64) -> Self {
         Self::from_bits(tcx, n as u128, ParamEnv::empty().and(tcx.types.usize))
     }
 
@@ -201,7 +201,11 @@ impl<'tcx> Const<'tcx> {
     }
 
     #[inline]
-    pub fn try_eval_usize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> Option<u64> {
+    pub fn try_eval_target_usize(
+        self,
+        tcx: TyCtxt<'tcx>,
+        param_env: ParamEnv<'tcx>,
+    ) -> Option<u64> {
         self.kind().eval(tcx, param_env).try_to_machine_usize(tcx)
     }
 
@@ -229,8 +233,8 @@ impl<'tcx> Const<'tcx> {
 
     #[inline]
     /// Panics if the value cannot be evaluated or doesn't contain a valid `usize`.
-    pub fn eval_usize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> u64 {
-        self.try_eval_usize(tcx, param_env)
+    pub fn eval_target_usize(self, tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>) -> u64 {
+        self.try_eval_target_usize(tcx, param_env)
             .unwrap_or_else(|| bug!("expected usize, got {:#?}", self))
     }
 
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 02088fffeb6..e67c89c194e 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1787,7 +1787,7 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn mk_array(self, ty: Ty<'tcx>, n: u64) -> Ty<'tcx> {
-        self.mk_ty(Array(ty, ty::Const::from_usize(self, n)))
+        self.mk_ty(Array(ty, ty::Const::from_target_usize(self, n)))
     }
 
     #[inline]
diff --git a/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs b/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
index 33f72729798..8d0c7bf2f47 100644
--- a/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
+++ b/compiler/rustc_middle/src/ty/inhabitedness/inhabited_predicate.rs
@@ -57,7 +57,7 @@ impl<'tcx> InhabitedPredicate<'tcx> {
         match self {
             Self::False => Ok(false),
             Self::True => Ok(true),
-            Self::ConstIsZero(const_) => match const_.try_eval_usize(tcx, param_env) {
+            Self::ConstIsZero(const_) => match const_.try_eval_target_usize(tcx, param_env) {
                 None | Some(0) => Ok(true),
                 Some(1..) => Ok(false),
             },
diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 3b22da41a57..8b08ea9a58c 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -511,8 +511,8 @@ pub fn super_relate_tys<'tcx, R: TypeRelation<'tcx>>(
                     // we however cannot end up with errors in `Relate` during both
                     // `type_of` and `predicates_of`. This means that evaluating the
                     // constants should not cause cycle errors here.
-                    let sz_a = sz_a.try_eval_usize(tcx, relation.param_env());
-                    let sz_b = sz_b.try_eval_usize(tcx, relation.param_env());
+                    let sz_a = sz_a.try_eval_target_usize(tcx, relation.param_env());
+                    let sz_b = sz_b.try_eval_target_usize(tcx, relation.param_env());
                     match (sz_a, sz_b) {
                         (Some(sz_a_val), Some(sz_b_val)) if sz_a_val != sz_b_val => Err(
                             TypeError::FixedArraySize(expected_found(relation, sz_a_val, sz_b_val)),
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index abde81236e2..c613b3627f2 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -1879,7 +1879,7 @@ impl<'tcx> Ty<'tcx> {
                         // The way we evaluate the `N` in `[T; N]` here only works since we use
                         // `simd_size_and_type` post-monomorphization. It will probably start to ICE
                         // if we use it in generic code. See the `simd-array-trait` ui test.
-                        (f0_len.eval_usize(tcx, ParamEnv::empty()) as u64, *f0_elem_ty)
+                        (f0_len.eval_target_usize(tcx, ParamEnv::empty()) as u64, *f0_elem_ty)
                     }
                     // Otherwise, the fields of this Adt are the SIMD components (and we assume they
                     // all have the same type).