diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/interpret/cast.rs')
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/cast.rs | 109 |
1 files changed, 56 insertions, 53 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs index bd897ffaafc..b9f88cf6352 100644 --- a/compiler/rustc_const_eval/src/interpret/cast.rs +++ b/compiler/rustc_const_eval/src/interpret/cast.rs @@ -24,41 +24,44 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { cast_ty: Ty<'tcx>, dest: &PlaceTy<'tcx, M::Provenance>, ) -> InterpResult<'tcx> { + // `cast_ty` will often be the same as `dest.ty`, but not always, since subtyping is still + // possible. + let cast_layout = + if cast_ty == dest.layout.ty { dest.layout } else { self.layout_of(cast_ty)? }; // FIXME: In which cases should we trigger UB when the source is uninit? match cast_kind { CastKind::PointerCoercion(PointerCoercion::Unsize) => { - let cast_ty = self.layout_of(cast_ty)?; - self.unsize_into(src, cast_ty, dest)?; + self.unsize_into(src, cast_layout, dest)?; } CastKind::PointerExposeAddress => { let src = self.read_immediate(src)?; - let res = self.pointer_expose_address_cast(&src, cast_ty)?; - self.write_immediate(res, dest)?; + let res = self.pointer_expose_address_cast(&src, cast_layout)?; + 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)?; + let res = self.pointer_from_exposed_address_cast(&src, cast_layout)?; + 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)?; + let res = self.int_to_int_or_float(&src, cast_layout)?; + 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)?; + let res = self.float_to_float_or_int(&src, cast_layout)?; + 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)?; + let res = self.ptr_to_ptr(&src, cast_layout)?; + self.write_immediate(*res, dest)?; } CastKind::PointerCoercion( @@ -87,7 +90,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { let fn_ptr = self.fn_ptr(FnVal::Instance(instance)); self.write_pointer(fn_ptr, dest)?; } - _ => span_bug!(self.cur_span(), "reify fn pointer on {:?}", src.layout.ty), + _ => span_bug!(self.cur_span(), "reify fn pointer on {}", src.layout.ty), } } @@ -98,7 +101,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { // No change to value self.write_immediate(*src, dest)?; } - _ => span_bug!(self.cur_span(), "fn to unsafe fn cast on {:?}", cast_ty), + _ => span_bug!(self.cur_span(), "fn to unsafe fn cast on {}", cast_ty), } } @@ -119,7 +122,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { let fn_ptr = self.fn_ptr(FnVal::Instance(instance)); self.write_pointer(fn_ptr, dest)?; } - _ => span_bug!(self.cur_span(), "closure fn pointer on {:?}", src.layout.ty), + _ => span_bug!(self.cur_span(), "closure fn pointer on {}", src.layout.ty), } } @@ -140,6 +143,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { CastKind::Transmute => { assert!(src.layout.is_sized()); assert!(dest.layout.is_sized()); + assert_eq!(cast_ty, dest.layout.ty); // we otherwise ignore `cast_ty` enirely... if src.layout.size != dest.layout.size { let src_bytes = src.layout.size.bytes(); let dest_bytes = dest.layout.size.bytes(); @@ -164,62 +168,61 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { pub fn int_to_int_or_float( &self, src: &ImmTy<'tcx, M::Provenance>, - cast_ty: Ty<'tcx>, - ) -> InterpResult<'tcx, Immediate<M::Provenance>> { + cast_to: TyAndLayout<'tcx>, + ) -> 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()); + assert!(cast_to.ty.is_floating_point() || cast_to.ty.is_integral() || cast_to.ty.is_char()); - Ok(self.cast_from_int_like(src.to_scalar(), src.layout, cast_ty)?.into()) + Ok(ImmTy::from_scalar( + self.cast_from_int_like(src.to_scalar(), src.layout, cast_to.ty)?, + cast_to, + )) } /// 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>> { + cast_to: TyAndLayout<'tcx>, + ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> { use rustc_type_ir::sty::TyKind::*; - match src.layout.ty.kind() { + 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_to.ty), + Float(FloatTy::F64) => self.cast_from_float(src.to_scalar().to_f64()?, cast_to.ty), _ => { - bug!("Can't cast 'Float' type into {:?}", cast_ty); + bug!("Can't cast 'Float' type into {}", cast_to.ty); } - } + }; + Ok(ImmTy::from_scalar(val, cast_to)) } /// 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>> { + cast_to: TyAndLayout<'tcx>, + ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> { assert!(src.layout.ty.is_any_ptr()); - assert!(cast_ty.is_unsafe_ptr()); + assert!(cast_to.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 { + if cast_to.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, cast_to)); } 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_eq!(cast_to.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, cast_to)), Immediate::Scalar(..) => span_bug!( self.cur_span(), - "{:?} input to a fat-to-thin cast ({:?} -> {:?})", + "{:?} input to a fat-to-thin cast ({} -> {})", *src, src.layout.ty, - cast_ty + cast_to.ty ), Immediate::Uninit => throw_ub!(InvalidUninitBytes(None)), }; @@ -229,10 +232,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { pub fn pointer_expose_address_cast( &mut self, src: &ImmTy<'tcx, M::Provenance>, - cast_ty: Ty<'tcx>, - ) -> InterpResult<'tcx, Immediate<M::Provenance>> { + cast_to: TyAndLayout<'tcx>, + ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> { assert_matches!(src.layout.ty.kind(), ty::RawPtr(_) | ty::FnPtr(_)); - assert!(cast_ty.is_integral()); + assert!(cast_to.ty.is_integral()); let scalar = src.to_scalar(); let ptr = scalar.to_pointer(self)?; @@ -240,16 +243,16 @@ 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()) + Ok(ImmTy::from_scalar(self.cast_from_int_like(scalar, src.layout, cast_to.ty)?, cast_to)) } pub fn pointer_from_exposed_address_cast( &self, src: &ImmTy<'tcx, M::Provenance>, - cast_ty: Ty<'tcx>, - ) -> InterpResult<'tcx, Immediate<M::Provenance>> { + cast_to: TyAndLayout<'tcx>, + ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> { assert!(src.layout.ty.is_integral()); - assert_matches!(cast_ty.kind(), ty::RawPtr(_)); + assert_matches!(cast_to.ty.kind(), ty::RawPtr(_)); // First cast to usize. let scalar = src.to_scalar(); @@ -258,12 +261,12 @@ 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()) + Ok(ImmTy::from_scalar(Scalar::from_maybe_pointer(ptr, self), cast_to)) } /// 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>, @@ -298,7 +301,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { } // Casts to bool are not permitted by rustc, no need to handle them here. - _ => span_bug!(self.cur_span(), "invalid int to {:?} cast", cast_ty), + _ => span_bug!(self.cur_span(), "invalid int to {} cast", cast_ty), }) } @@ -331,7 +334,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { // float -> f64 Float(FloatTy::F64) => Scalar::from_f64(f.convert(&mut false).value), // That's it. - _ => span_bug!(self.cur_span(), "invalid float to {:?} cast", dest_ty), + _ => span_bug!(self.cur_span(), "invalid float to {} cast", dest_ty), } } @@ -390,7 +393,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { span_bug!( self.cur_span(), - "invalid pointer unsizing {:?} -> {:?}", + "invalid pointer unsizing {} -> {}", src.layout.ty, cast_ty ) @@ -404,7 +407,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { cast_ty: TyAndLayout<'tcx>, dest: &PlaceTy<'tcx, M::Provenance>, ) -> InterpResult<'tcx> { - trace!("Unsizing {:?} of type {} into {:?}", *src, src.layout.ty, cast_ty.ty); + trace!("Unsizing {:?} of type {} into {}", *src, src.layout.ty, cast_ty.ty); match (&src.layout.ty.kind(), &cast_ty.ty.kind()) { (&ty::Ref(_, s, _), &ty::Ref(_, c, _) | &ty::RawPtr(TypeAndMut { ty: c, .. })) | (&ty::RawPtr(TypeAndMut { ty: s, .. }), &ty::RawPtr(TypeAndMut { ty: c, .. })) => { |