use std::assert_matches::assert_matches;
use rustc_apfloat::ieee::{Double, Half, Quad, Single};
use rustc_apfloat::{Float, FloatConvert};
use rustc_middle::mir::interpret::{InterpResult, PointerArithmetic, Scalar};
use rustc_middle::mir::CastKind;
use rustc_middle::ty::adjustment::PointerCoercion;
use rustc_middle::ty::layout::{IntegerExt, LayoutOf, TyAndLayout};
use rustc_middle::ty::{self, FloatTy, Ty};
use rustc_middle::{bug, span_bug};
use rustc_target::abi::Integer;
use rustc_type_ir::TyKind::*;
use tracing::trace;
use super::util::ensure_monomorphic_enough;
use super::{
err_inval, throw_ub, throw_ub_custom, FnVal, ImmTy, Immediate, InterpCx, Machine, OpTy, PlaceTy,
};
use crate::fluent_generated as fluent;
impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
pub fn cast(
&mut self,
src: &OpTy<'tcx, M::Provenance>,
cast_kind: CastKind,
cast_ty: Ty<'tcx>,
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx> {
let cast_layout =
if cast_ty == dest.layout.ty { dest.layout } else { self.layout_of(cast_ty)? };
match cast_kind {
CastKind::PointerCoercion(PointerCoercion::Unsize) => {
self.unsize_into(src, cast_layout, dest)?;
}
CastKind::PointerExposeProvenance => {
let src = self.read_immediate(src)?;
let res = self.pointer_expose_provenance_cast(&src, cast_layout)?;
self.write_immediate(*res, dest)?;
}
CastKind::PointerWithExposedProvenance => {
let src = self.read_immediate(src)?;
let res = self.pointer_with_exposed_provenance_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_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_layout)?;
self.write_immediate(*res, dest)?;
}
CastKind::FnPtrToPtr | CastKind::PtrToPtr => {
let src = self.read_immediate(src)?;
let res = self.ptr_to_ptr(&src, cast_layout)?;
self.write_immediate(*res, dest)?;
}
CastKind::PointerCoercion(
PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
) => {
bug!("{cast_kind:?} casts are for borrowck only, not runtime MIR");
}
CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {
ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;
match *src.layout.ty.kind() {
ty::FnDef(def_id, args) => {
let instance = ty::Instance::resolve_for_fn_ptr(
*self.tcx,
self.param_env,
def_id,
args,
)
.ok_or_else(|| err_inval!(TooGeneric))?;
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),
}
}
CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer) => {
let src = self.read_immediate(src)?;
match cast_ty.kind() {
ty::FnPtr(..) => {
self.write_immediate(*src, dest)?;
}
_ => span_bug!(self.cur_span(), "fn to unsafe fn cast on {}", cast_ty),
}
}
CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)) => {
ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;
match *src.layout.ty.kind() {
ty::Closure(def_id, args) => {
let instance = ty::Instance::resolve_closure(
*self.tcx,
def_id,
args,
ty::ClosureKind::FnOnce,
);
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),
}
}
CastKind::DynStar => {
if let ty::Dynamic(data, _, ty::DynStar) = cast_ty.kind() {
let vtable = self.get_vtable_ptr(src.layout.ty, data.principal())?;
let vtable = Scalar::from_maybe_pointer(vtable, self);
let data = self.read_immediate(src)?.to_scalar();
let _assert_pointer_like = data.to_pointer(self)?;
let val = Immediate::ScalarPair(data, vtable);
self.write_immediate(val, dest)?;
} else {
bug!()
}
}
CastKind::Transmute => {
assert!(src.layout.is_sized());
assert!(dest.layout.is_sized());
assert_eq!(cast_ty, dest.layout.ty); if src.layout.size != dest.layout.size {
throw_ub_custom!(
fluent::const_eval_invalid_transmute,
src_bytes = src.layout.size.bytes(),
dest_bytes = dest.layout.size.bytes(),
src = src.layout.ty,
dest = dest.layout.ty,
);
}
self.copy_op_allow_transmute(src, dest)?;
}
}
Ok(())
}
pub fn int_to_int_or_float(
&self,
src: &ImmTy<'tcx, 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_to.ty.is_floating_point() || cast_to.ty.is_integral() || cast_to.ty.is_char());
Ok(ImmTy::from_scalar(
self.cast_from_int_like(src.to_scalar(), src.layout, cast_to.ty)?,
cast_to,
))
}
pub fn float_to_float_or_int(
&self,
src: &ImmTy<'tcx, M::Provenance>,
cast_to: TyAndLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
use rustc_type_ir::TyKind::*;
let Float(fty) = src.layout.ty.kind() else {
bug!("FloatToFloat/FloatToInt cast: source type {} is not a float type", src.layout.ty)
};
let val = match fty {
FloatTy::F16 => self.cast_from_float(src.to_scalar().to_f16()?, cast_to.ty),
FloatTy::F32 => self.cast_from_float(src.to_scalar().to_f32()?, cast_to.ty),
FloatTy::F64 => self.cast_from_float(src.to_scalar().to_f64()?, cast_to.ty),
FloatTy::F128 => self.cast_from_float(src.to_scalar().to_f128()?, cast_to.ty),
};
Ok(ImmTy::from_scalar(val, cast_to))
}
pub fn ptr_to_ptr(
&self,
src: &ImmTy<'tcx, M::Provenance>,
cast_to: TyAndLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
assert!(src.layout.ty.is_any_ptr());
assert!(cast_to.ty.is_unsafe_ptr());
if cast_to.size == src.layout.size {
return Ok(ImmTy::from_immediate(**src, cast_to));
} else {
assert_eq!(src.layout.size, 2 * 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(ImmTy::from_scalar(data, cast_to)),
Immediate::Scalar(..) => span_bug!(
self.cur_span(),
"{:?} input to a fat-to-thin cast ({} -> {})",
*src,
src.layout.ty,
cast_to.ty
),
Immediate::Uninit => throw_ub!(InvalidUninitBytes(None)),
};
}
}
pub fn pointer_expose_provenance_cast(
&mut self,
src: &ImmTy<'tcx, M::Provenance>,
cast_to: TyAndLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
assert_matches!(src.layout.ty.kind(), ty::RawPtr(_, _) | ty::FnPtr(..));
assert!(cast_to.ty.is_integral());
let scalar = src.to_scalar();
let ptr = scalar.to_pointer(self)?;
match ptr.into_pointer_or_addr() {
Ok(ptr) => M::expose_ptr(self, ptr)?,
Err(_) => {} };
Ok(ImmTy::from_scalar(self.cast_from_int_like(scalar, src.layout, cast_to.ty)?, cast_to))
}
pub fn pointer_with_exposed_provenance_cast(
&self,
src: &ImmTy<'tcx, M::Provenance>,
cast_to: TyAndLayout<'tcx>,
) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> {
assert!(src.layout.ty.is_integral());
assert_matches!(cast_to.ty.kind(), ty::RawPtr(_, _));
let scalar = src.to_scalar();
let addr = self.cast_from_int_like(scalar, src.layout, self.tcx.types.usize)?;
let addr = addr.to_target_usize(self)?;
let ptr = M::ptr_from_addr_cast(self, addr)?;
Ok(ImmTy::from_scalar(Scalar::from_maybe_pointer(ptr, self), cast_to))
}
fn cast_from_int_like(
&self,
scalar: Scalar<M::Provenance>, src_layout: TyAndLayout<'tcx>,
cast_ty: Ty<'tcx>,
) -> InterpResult<'tcx, Scalar<M::Provenance>> {
let signed = src_layout.abi.is_signed(); let v = match src_layout.ty.kind() {
Uint(_) | RawPtr(..) | FnPtr(..) => scalar.to_uint(src_layout.size)?,
Int(_) => scalar.to_int(src_layout.size)? as u128, Bool => scalar.to_bool()?.into(),
Char => scalar.to_char()?.into(),
_ => span_bug!(self.cur_span(), "invalid int-like cast from {}", src_layout.ty),
};
Ok(match *cast_ty.kind() {
Int(_) | Uint(_) => {
let size = match *cast_ty.kind() {
Int(t) => Integer::from_int_ty(self, t).size(),
Uint(t) => Integer::from_uint_ty(self, t).size(),
_ => bug!(),
};
let v = size.truncate(v);
Scalar::from_uint(v, size)
}
Float(fty) if signed => {
let v = v as i128;
match fty {
FloatTy::F16 => Scalar::from_f16(Half::from_i128(v).value),
FloatTy::F32 => Scalar::from_f32(Single::from_i128(v).value),
FloatTy::F64 => Scalar::from_f64(Double::from_i128(v).value),
FloatTy::F128 => Scalar::from_f128(Quad::from_i128(v).value),
}
}
Float(fty) => match fty {
FloatTy::F16 => Scalar::from_f16(Half::from_u128(v).value),
FloatTy::F32 => Scalar::from_f32(Single::from_u128(v).value),
FloatTy::F64 => Scalar::from_f64(Double::from_u128(v).value),
FloatTy::F128 => Scalar::from_f128(Quad::from_u128(v).value),
},
Char => Scalar::from_u32(u8::try_from(v).unwrap().into()),
_ => span_bug!(self.cur_span(), "invalid int to {} cast", cast_ty),
})
}
fn cast_from_float<F>(&self, f: F, dest_ty: Ty<'tcx>) -> Scalar<M::Provenance>
where
F: Float
+ Into<Scalar<M::Provenance>>
+ FloatConvert<Half>
+ FloatConvert<Single>
+ FloatConvert<Double>
+ FloatConvert<Quad>,
{
use rustc_type_ir::TyKind::*;
fn adjust_nan<
'tcx,
M: Machine<'tcx>,
F1: rustc_apfloat::Float + FloatConvert<F2>,
F2: rustc_apfloat::Float,
>(
ecx: &InterpCx<'tcx, M>,
f1: F1,
f2: F2,
) -> F2 {
if f2.is_nan() { M::generate_nan(ecx, &[f1]) } else { f2 }
}
match *dest_ty.kind() {
Uint(t) => {
let size = Integer::from_uint_ty(self, t).size();
let v = f.to_u128(size.bits_usize()).value;
Scalar::from_uint(v, size)
}
Int(t) => {
let size = Integer::from_int_ty(self, t).size();
let v = f.to_i128(size.bits_usize()).value;
Scalar::from_int(v, size)
}
Float(fty) => match fty {
FloatTy::F16 => Scalar::from_f16(adjust_nan(self, f, f.convert(&mut false).value)),
FloatTy::F32 => Scalar::from_f32(adjust_nan(self, f, f.convert(&mut false).value)),
FloatTy::F64 => Scalar::from_f64(adjust_nan(self, f, f.convert(&mut false).value)),
FloatTy::F128 => {
Scalar::from_f128(adjust_nan(self, f, f.convert(&mut false).value))
}
},
_ => span_bug!(self.cur_span(), "invalid float to {} cast", dest_ty),
}
}
fn unsize_into_ptr(
&mut self,
src: &OpTy<'tcx, M::Provenance>,
dest: &PlaceTy<'tcx, M::Provenance>,
source_ty: Ty<'tcx>,
cast_ty: Ty<'tcx>,
) -> InterpResult<'tcx> {
let (src_pointee_ty, dest_pointee_ty) =
self.tcx.struct_lockstep_tails_for_codegen(source_ty, cast_ty, self.param_env);
match (src_pointee_ty.kind(), dest_pointee_ty.kind()) {
(&ty::Array(_, length), &ty::Slice(_)) => {
let ptr = self.read_pointer(src)?;
let val = Immediate::new_slice(
ptr,
length.eval_target_usize(*self.tcx, self.param_env),
self,
);
self.write_immediate(val, dest)
}
(ty::Dynamic(data_a, _, ty::Dyn), ty::Dynamic(data_b, _, ty::Dyn)) => {
let val = self.read_immediate(src)?;
if data_a == data_b {
return self.write_immediate(*val, dest);
}
let (old_data, old_vptr) = val.to_scalar_pair();
let old_data = old_data.to_pointer(self)?;
let old_vptr = old_vptr.to_pointer(self)?;
let ty = self.get_ptr_vtable_ty(old_vptr, Some(data_a))?;
if cfg!(debug_assertions) {
let vptr_entry_idx =
self.tcx.supertrait_vtable_slot((src_pointee_ty, dest_pointee_ty));
let vtable_entries = self.vtable_entries(data_a.principal(), ty);
if let Some(entry_idx) = vptr_entry_idx {
let Some(&ty::VtblEntry::TraitVPtr(upcast_trait_ref)) =
vtable_entries.get(entry_idx)
else {
span_bug!(
self.cur_span(),
"invalid vtable entry index in {} -> {} upcast",
src_pointee_ty,
dest_pointee_ty
);
};
let erased_trait_ref = upcast_trait_ref
.map_bound(|r| ty::ExistentialTraitRef::erase_self_ty(*self.tcx, r));
assert!(
data_b
.principal()
.is_some_and(|b| self.eq_in_param_env(erased_trait_ref, b))
);
} else {
let vtable_entries_b = self.vtable_entries(data_b.principal(), ty);
assert!(&vtable_entries[..vtable_entries_b.len()] == vtable_entries_b);
};
}
let new_vptr = self.get_vtable_ptr(ty, data_b.principal())?;
self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest)
}
(_, &ty::Dynamic(data, _, ty::Dyn)) => {
let vtable = self.get_vtable_ptr(src_pointee_ty, data.principal())?;
let ptr = self.read_pointer(src)?;
let val = Immediate::new_dyn_trait(ptr, vtable, &*self.tcx);
self.write_immediate(val, dest)
}
_ => {
ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;
ensure_monomorphic_enough(*self.tcx, cast_ty)?;
span_bug!(
self.cur_span(),
"invalid pointer unsizing {} -> {}",
src.layout.ty,
cast_ty
)
}
}
}
pub fn unsize_into(
&mut self,
src: &OpTy<'tcx, M::Provenance>,
cast_ty: TyAndLayout<'tcx>,
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx> {
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(c, _))
| (&ty::RawPtr(s, _), &ty::RawPtr(c, _)) => self.unsize_into_ptr(src, dest, s, c),
(&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {
assert_eq!(def_a, def_b); let mut found_cast_field = false;
for i in 0..src.layout.fields.count() {
let cast_ty_field = cast_ty.field(self, i);
let src_field = self.project_field(src, i)?;
let dst_field = self.project_field(dest, i)?;
if src_field.layout.is_1zst() && cast_ty_field.is_1zst() {
} else if src_field.layout.ty == cast_ty_field.ty {
self.copy_op(&src_field, &dst_field)?;
} else {
if found_cast_field {
span_bug!(self.cur_span(), "unsize_into: more than one field to cast");
}
found_cast_field = true;
self.unsize_into(&src_field, cast_ty_field, &dst_field)?;
}
}
Ok(())
}
_ => {
ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;
ensure_monomorphic_enough(*self.tcx, cast_ty.ty)?;
span_bug!(
self.cur_span(),
"unsize_into: invalid conversion: {:?} -> {:?}",
src.layout,
dest.layout
)
}
}
}
}