interpret: more consistently use ImmTy in operators and casts

Author: RalfJung

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -3,7 +3,7 @@ use rustc_hir::{LangItem, CRATE_HIR_ID};
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::PointerArithmetic;
 use rustc_middle::ty::layout::{FnAbiOf, TyAndLayout};
-use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt};
 use rustc_session::lint::builtin::INVALID_ALIGNMENT;
 use std::borrow::Borrow;
 use std::hash::Hash;
@@ -596,7 +596,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         _bin_op: mir::BinOp,
         _left: &ImmTy<'tcx>,
         _right: &ImmTy<'tcx>,
-    ) -> InterpResult<'tcx, (Scalar, bool, Ty<'tcx>)> {
+    ) -> InterpResult<'tcx, (ImmTy<'tcx>, bool)> {
         throw_unsup_format!("pointer arithmetic or comparison is not supported at compile-time");
     }
 

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -34,31 +34,31 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             CastKind::PointerExposeAddress => {
                 let src = self.read_immediate(src)?;
                 let res = self.pointer_expose_address_cast(&src, cast_ty)?;
-                self.write_immediate(res, dest)?;
+                self.write_immediate(*res, dest)?;
             }
 
             CastKind::PointerFromExposedAddress => {
                 let src = self.read_immediate(src)?;
                 let res = self.pointer_from_exposed_address_cast(&src, cast_ty)?;
-                self.write_immediate(res, dest)?;
+                self.write_immediate(*res, dest)?;
             }
 
             CastKind::IntToInt | CastKind::IntToFloat => {
                 let src = self.read_immediate(src)?;
                 let res = self.int_to_int_or_float(&src, cast_ty)?;
-                self.write_immediate(res, dest)?;
+                self.write_immediate(*res, dest)?;
             }
 
             CastKind::FloatToFloat | CastKind::FloatToInt => {
                 let src = self.read_immediate(src)?;
                 let res = self.float_to_float_or_int(&src, cast_ty)?;
-                self.write_immediate(res, dest)?;
+                self.write_immediate(*res, dest)?;
             }
 
             CastKind::FnPtrToPtr | CastKind::PtrToPtr => {
                 let src = self.read_immediate(src)?;
                 let res = self.ptr_to_ptr(&src, cast_ty)?;
-                self.write_immediate(res, dest)?;
+                self.write_immediate(*res, dest)?;
             }
 
             CastKind::PointerCoercion(
@@ -165,55 +165,57 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         &self,
         src: &ImmTy<'tcx, M::Provenance>,
         cast_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, Immediate<M::Provenance>> {
+    ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         assert!(src.layout.ty.is_integral() || src.layout.ty.is_char() || src.layout.ty.is_bool());
         assert!(cast_ty.is_floating_point() || cast_ty.is_integral() || cast_ty.is_char());
 
-        Ok(self.cast_from_int_like(src.to_scalar(), src.layout, cast_ty)?.into())
+        let layout = self.layout_of(cast_ty)?;
+        Ok(ImmTy::from_scalar(
+            self.cast_from_int_like(src.to_scalar(), src.layout, cast_ty)?,
+            layout,
+        ))
     }
 
     /// Handles 'FloatToFloat' and 'FloatToInt' casts.
     pub fn float_to_float_or_int(
         &self,
         src: &ImmTy<'tcx, M::Provenance>,
         cast_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, Immediate<M::Provenance>> {
+    ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         use rustc_type_ir::sty::TyKind::*;
 
-        match src.layout.ty.kind() {
+        let layout = self.layout_of(cast_ty)?;
+        let val = match src.layout.ty.kind() {
             // Floating point
-            Float(FloatTy::F32) => {
-                return Ok(self.cast_from_float(src.to_scalar().to_f32()?, cast_ty).into());
-            }
-            Float(FloatTy::F64) => {
-                return Ok(self.cast_from_float(src.to_scalar().to_f64()?, cast_ty).into());
-            }
+            Float(FloatTy::F32) => self.cast_from_float(src.to_scalar().to_f32()?, cast_ty),
+            Float(FloatTy::F64) => self.cast_from_float(src.to_scalar().to_f64()?, cast_ty),
             _ => {
                 bug!("Can't cast 'Float' type into {:?}", cast_ty);
             }
-        }
+        };
+        Ok(ImmTy::from_scalar(val, layout))
     }
 
     /// Handles 'FnPtrToPtr' and 'PtrToPtr' casts.
     pub fn ptr_to_ptr(
         &self,
         src: &ImmTy<'tcx, M::Provenance>,
         cast_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, Immediate<M::Provenance>> {
+    ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         assert!(src.layout.ty.is_any_ptr());
         assert!(cast_ty.is_unsafe_ptr());
         // Handle casting any ptr to raw ptr (might be a fat ptr).
         let dest_layout = self.layout_of(cast_ty)?;
         if dest_layout.size == src.layout.size {
             // Thin or fat pointer that just hast the ptr kind of target type changed.
-            return Ok(**src);
+            return Ok(ImmTy::from_immediate(**src, dest_layout));
         } else {
             // Casting the metadata away from a fat ptr.
             assert_eq!(src.layout.size, 2 * self.pointer_size());
             assert_eq!(dest_layout.size, self.pointer_size());
             assert!(src.layout.ty.is_unsafe_ptr());
             return match **src {
-                Immediate::ScalarPair(data, _) => Ok(data.into()),
+                Immediate::ScalarPair(data, _) => Ok(ImmTy::from_scalar(data, dest_layout)),
                 Immediate::Scalar(..) => span_bug!(
                     self.cur_span(),
                     "{:?} input to a fat-to-thin cast ({:?} -> {:?})",
@@ -230,7 +232,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         &mut self,
         src: &ImmTy<'tcx, M::Provenance>,
         cast_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, Immediate<M::Provenance>> {
+    ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         assert_matches!(src.layout.ty.kind(), ty::RawPtr(_) | ty::FnPtr(_));
         assert!(cast_ty.is_integral());
 
@@ -240,14 +242,15 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             Ok(ptr) => M::expose_ptr(self, ptr)?,
             Err(_) => {} // Do nothing, exposing an invalid pointer (`None` provenance) is a NOP.
         };
-        Ok(self.cast_from_int_like(scalar, src.layout, cast_ty)?.into())
+        let layout = self.layout_of(cast_ty)?;
+        Ok(ImmTy::from_scalar(self.cast_from_int_like(scalar, src.layout, cast_ty)?, layout))
     }
 
     pub fn pointer_from_exposed_address_cast(
         &self,
         src: &ImmTy<'tcx, M::Provenance>,
         cast_ty: Ty<'tcx>,
-    ) -> InterpResult<'tcx, Immediate<M::Provenance>> {
+    ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
         assert!(src.layout.ty.is_integral());
         assert_matches!(cast_ty.kind(), ty::RawPtr(_));
 
@@ -258,12 +261,13 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
         // Then turn address into pointer.
         let ptr = M::ptr_from_addr_cast(&self, addr)?;
-        Ok(Scalar::from_maybe_pointer(ptr, self).into())
+        let layout = self.layout_of(cast_ty)?;
+        Ok(ImmTy::from_scalar(Scalar::from_maybe_pointer(ptr, self), layout))
     }
 
     /// Low-level cast helper function. This works directly on scalars and can take 'int-like' input
     /// type (basically everything with a scalar layout) to int/float/char types.
-    pub fn cast_from_int_like(
+    fn cast_from_int_like(
         &self,
         scalar: Scalar<M::Provenance>, // input value (there is no ScalarTy so we separate data+layout)
         src_layout: TyAndLayout<'tcx>,

compiler/rustc_const_eval/src/interpret/discriminant.rs

@@ -76,7 +76,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     let niche_start_val = ImmTy::from_uint(niche_start, tag_layout);
                     let variant_index_relative_val =
                         ImmTy::from_uint(variant_index_relative, tag_layout);
-                    let tag_val = self.binary_op(
+                    let tag_val = self.wrapping_binary_op(
                         mir::BinOp::Add,
                         &variant_index_relative_val,
                         &niche_start_val,
@@ -153,19 +153,18 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // Figure out which discriminant and variant this corresponds to.
         let index = match *tag_encoding {
             TagEncoding::Direct => {
-                let scalar = tag_val.to_scalar();
                 // Generate a specific error if `tag_val` is not an integer.
                 // (`tag_bits` itself is only used for error messages below.)
-                let tag_bits = scalar
+                let tag_bits = tag_val
+                    .to_scalar()
                     .try_to_int()
                     .map_err(|dbg_val| err_ub!(InvalidTag(dbg_val)))?
                     .assert_bits(tag_layout.size);
                 // Cast bits from tag layout to discriminant layout.
                 // After the checks we did above, this cannot fail, as
                 // discriminants are int-like.
-                let discr_val =
-                    self.cast_from_int_like(scalar, tag_val.layout, discr_layout.ty).unwrap();
-                let discr_bits = discr_val.assert_bits(discr_layout.size);
+                let discr_val = self.int_to_int_or_float(&tag_val, discr_layout.ty).unwrap();
+                let discr_bits = discr_val.to_scalar().assert_bits(discr_layout.size);
                 // Convert discriminant to variant index, and catch invalid discriminants.
                 let index = match *ty.kind() {
                     ty::Adt(adt, _) => {
@@ -208,7 +207,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         let tag_val = ImmTy::from_uint(tag_bits, tag_layout);
                         let niche_start_val = ImmTy::from_uint(niche_start, tag_layout);
                         let variant_index_relative_val =
-                            self.binary_op(mir::BinOp::Sub, &tag_val, &niche_start_val)?;
+                            self.wrapping_binary_op(mir::BinOp::Sub, &tag_val, &niche_start_val)?;
                         let variant_index_relative =
                             variant_index_relative_val.to_scalar().assert_bits(tag_val.layout.size);
                         // Check if this is in the range that indicates an actual discriminant.

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -307,7 +307,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let dist = {
                     // Addresses are unsigned, so this is a `usize` computation. We have to do the
                     // overflow check separately anyway.
-                    let (val, overflowed, _ty) = {
+                    let (val, overflowed) = {
                         let a_offset = ImmTy::from_uint(a_offset, usize_layout);
                         let b_offset = ImmTy::from_uint(b_offset, usize_layout);
                         self.overflowing_binary_op(BinOp::Sub, &a_offset, &b_offset)?
@@ -324,7 +324,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         // The signed form of the intrinsic allows this. If we interpret the
                         // difference as isize, we'll get the proper signed difference. If that
                         // seems *positive*, they were more than isize::MAX apart.
-                        let dist = val.to_target_isize(self)?;
+                        let dist = val.to_scalar().to_target_isize(self)?;
                         if dist >= 0 {
                             throw_ub_custom!(
                                 fluent::const_eval_offset_from_underflow,
@@ -334,7 +334,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                         dist
                     } else {
                         // b >= a
-                        let dist = val.to_target_isize(self)?;
+                        let dist = val.to_scalar().to_target_isize(self)?;
                         // If converting to isize produced a *negative* result, we had an overflow
                         // because they were more than isize::MAX apart.
                         if dist < 0 {
@@ -504,9 +504,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         // Performs an exact division, resulting in undefined behavior where
         // `x % y != 0` or `y == 0` or `x == T::MIN && y == -1`.
         // First, check x % y != 0 (or if that computation overflows).
-        let (res, overflow, _ty) = self.overflowing_binary_op(BinOp::Rem, &a, &b)?;
+        let (res, overflow) = self.overflowing_binary_op(BinOp::Rem, &a, &b)?;
         assert!(!overflow); // All overflow is UB, so this should never return on overflow.
-        if res.assert_bits(a.layout.size) != 0 {
+        if res.to_scalar().assert_bits(a.layout.size) != 0 {
             throw_ub_custom!(
                 fluent::const_eval_exact_div_has_remainder,
                 a = format!("{a}"),
@@ -524,7 +524,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         r: &ImmTy<'tcx, M::Provenance>,
     ) -> InterpResult<'tcx, Scalar<M::Provenance>> {
         assert!(matches!(mir_op, BinOp::Add | BinOp::Sub));
-        let (val, overflowed, _ty) = self.overflowing_binary_op(mir_op, l, r)?;
+        let (val, overflowed) = self.overflowing_binary_op(mir_op, l, r)?;
         Ok(if overflowed {
             let size = l.layout.size;
             let num_bits = size.bits();
@@ -556,7 +556,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 }
             }
         } else {
-            val
+            val.to_scalar()
         })
     }
 

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -9,7 +9,7 @@ use std::hash::Hash;
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
 use rustc_middle::mir;
 use rustc_middle::ty::layout::TyAndLayout;
-use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::def_id::DefId;
 use rustc_target::abi::{Align, Size};
 use rustc_target::spec::abi::Abi as CallAbi;
@@ -18,7 +18,7 @@ use crate::const_eval::CheckAlignment;
 
 use super::{
     AllocBytes, AllocId, AllocRange, Allocation, ConstAllocation, FnArg, Frame, ImmTy, InterpCx,
-    InterpResult, MPlaceTy, MemoryKind, OpTy, PlaceTy, Pointer, Provenance, Scalar,
+    InterpResult, MPlaceTy, MemoryKind, OpTy, PlaceTy, Pointer, Provenance,
 };
 
 /// Data returned by Machine::stack_pop,
@@ -238,7 +238,7 @@ pub trait Machine<'mir, 'tcx: 'mir>: Sized {
         bin_op: mir::BinOp,
         left: &ImmTy<'tcx, Self::Provenance>,
         right: &ImmTy<'tcx, Self::Provenance>,
-    ) -> InterpResult<'tcx, (Scalar<Self::Provenance>, bool, Ty<'tcx>)>;
+    ) -> InterpResult<'tcx, (ImmTy<'tcx, Self::Provenance>, bool)>;
 
     /// Called before writing the specified `local` of the `frame`.
     /// Since writing a ZST is not actually accessing memory or locals, this is never invoked

compiler/rustc_const_eval/src/interpret/operand.rs

@@ -8,7 +8,7 @@ use either::{Either, Left, Right};
 use rustc_hir::def::Namespace;
 use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
 use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter};
-use rustc_middle::ty::{ConstInt, Ty};
+use rustc_middle::ty::{ConstInt, Ty, TyCtxt};
 use rustc_middle::{mir, ty};
 use rustc_target::abi::{self, Abi, Align, HasDataLayout, Size};
 
@@ -188,6 +188,12 @@ impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> {
         Self::from_scalar(Scalar::from_int(i, layout.size), layout)
     }
 
+    #[inline]
+    pub fn from_bool(b: bool, tcx: TyCtxt<'tcx>) -> Self {
+        let layout = tcx.layout_of(ty::ParamEnv::reveal_all().and(tcx.types.bool)).unwrap();
+        Self::from_scalar(Scalar::from_bool(b), layout)
+    }
+
     #[inline]
     pub fn to_const_int(self) -> ConstInt {
         assert!(self.layout.ty.is_integral());