Rollup merge of #94681 - RalfJung:miri-cast, r=oli-obk
CTFE engine: expose misc_cast to Miri We need that to implement `simd_cast`/`simd_as` in Miri. While at it, also change other code outside `cast.rs` to use `misc_cast` instead of lower-level methods. r? `@oli-obk`
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commit
f7eb3830df
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@ -97,7 +97,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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Ok(())
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Ok(())
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}
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}
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fn misc_cast(
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pub fn misc_cast(
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&self,
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&self,
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src: &ImmTy<'tcx, M::PointerTag>,
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src: &ImmTy<'tcx, M::PointerTag>,
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cast_ty: Ty<'tcx>,
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cast_ty: Ty<'tcx>,
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@ -139,7 +139,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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if let Some(discr) = src.layout.ty.discriminant_for_variant(*self.tcx, index) {
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if let Some(discr) = src.layout.ty.discriminant_for_variant(*self.tcx, index) {
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assert!(src.layout.is_zst());
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assert!(src.layout.is_zst());
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let discr_layout = self.layout_of(discr.ty)?;
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let discr_layout = self.layout_of(discr.ty)?;
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return Ok(self.cast_from_scalar(discr.val, discr_layout, cast_ty).into());
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return Ok(self.cast_from_int_like(discr.val, discr_layout, cast_ty).into());
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}
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}
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}
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}
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Variants::Multiple { .. } => {}
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Variants::Multiple { .. } => {}
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@ -169,17 +169,17 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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}
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}
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}
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}
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// # The remaining source values are scalar.
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// # The remaining source values are scalar and "int-like".
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// For all remaining casts, we either
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// For all remaining casts, we either
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// (a) cast a raw ptr to usize, or
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// (a) cast a raw ptr to usize, or
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// (b) cast from an integer-like (including bool, char, enums).
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// (b) cast from an integer-like (including bool, char, enums).
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// In both cases we want the bits.
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// In both cases we want the bits.
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let bits = src.to_scalar()?.to_bits(src.layout.size)?;
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let bits = src.to_scalar()?.to_bits(src.layout.size)?;
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Ok(self.cast_from_scalar(bits, src.layout, cast_ty).into())
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Ok(self.cast_from_int_like(bits, src.layout, cast_ty).into())
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}
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}
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pub(super) fn cast_from_scalar(
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fn cast_from_int_like(
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&self,
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&self,
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v: u128, // raw bits (there is no ScalarTy so we separate data+layout)
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v: u128, // raw bits (there is no ScalarTy so we separate data+layout)
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src_layout: TyAndLayout<'tcx>,
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src_layout: TyAndLayout<'tcx>,
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@ -681,18 +681,22 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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let tag_val = self.read_immediate(&self.operand_field(op, tag_field)?)?;
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let tag_val = self.read_immediate(&self.operand_field(op, tag_field)?)?;
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assert_eq!(tag_layout.size, tag_val.layout.size);
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assert_eq!(tag_layout.size, tag_val.layout.size);
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assert_eq!(tag_layout.abi.is_signed(), tag_val.layout.abi.is_signed());
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assert_eq!(tag_layout.abi.is_signed(), tag_val.layout.abi.is_signed());
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let tag_val = tag_val.to_scalar()?;
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trace!("tag value: {}", tag_val);
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trace!("tag value: {:?}", tag_val);
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// Figure out which discriminant and variant this corresponds to.
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// Figure out which discriminant and variant this corresponds to.
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Ok(match *tag_encoding {
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Ok(match *tag_encoding {
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TagEncoding::Direct => {
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TagEncoding::Direct => {
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// Generate a specific error if `tag_val` is not an integer.
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// (`tag_bits` itself is only used for error messages below.)
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let tag_bits = tag_val
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let tag_bits = tag_val
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.to_scalar()?
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.try_to_int()
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.try_to_int()
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.map_err(|dbg_val| err_ub!(InvalidTag(dbg_val)))?
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.map_err(|dbg_val| err_ub!(InvalidTag(dbg_val)))?
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.assert_bits(tag_layout.size);
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.assert_bits(tag_layout.size);
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// Cast bits from tag layout to discriminant layout.
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// Cast bits from tag layout to discriminant layout.
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let discr_val = self.cast_from_scalar(tag_bits, tag_layout, discr_layout.ty);
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// After the checks we did above, this cannot fail.
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let discr_val =
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self.misc_cast(&tag_val, discr_layout.ty).unwrap().to_scalar().unwrap();
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let discr_bits = discr_val.assert_bits(discr_layout.size);
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let discr_bits = discr_val.assert_bits(discr_layout.size);
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// Convert discriminant to variant index, and catch invalid discriminants.
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// Convert discriminant to variant index, and catch invalid discriminants.
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let index = match *op.layout.ty.kind() {
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let index = match *op.layout.ty.kind() {
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@ -712,6 +716,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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(discr_val, index.0)
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(discr_val, index.0)
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}
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}
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TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
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TagEncoding::Niche { dataful_variant, ref niche_variants, niche_start } => {
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let tag_val = tag_val.to_scalar()?;
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// Compute the variant this niche value/"tag" corresponds to. With niche layout,
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// Compute the variant this niche value/"tag" corresponds to. With niche layout,
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// discriminant (encoded in niche/tag) and variant index are the same.
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// discriminant (encoded in niche/tag) and variant index are the same.
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let variants_start = niche_variants.start().as_u32();
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let variants_start = niche_variants.start().as_u32();
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