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Diffstat (limited to '')
-rw-r--r-- | compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs new file mode 100644 index 000000000..f9847742f --- /dev/null +++ b/compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs @@ -0,0 +1,196 @@ +use rustc_data_structures::intern::Interned; +use rustc_hir::def_id::CrateNum; +use rustc_hir::definitions::DisambiguatedDefPathData; +use rustc_middle::mir::interpret::{Allocation, ConstAllocation}; +use rustc_middle::ty::{ + self, + print::{PrettyPrinter, Print, Printer}, + subst::{GenericArg, GenericArgKind}, + Ty, TyCtxt, +}; +use std::fmt::Write; + +struct AbsolutePathPrinter<'tcx> { + tcx: TyCtxt<'tcx>, + path: String, +} + +impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> { + type Error = std::fmt::Error; + + type Path = Self; + type Region = Self; + type Type = Self; + type DynExistential = Self; + type Const = Self; + + fn tcx(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> { + Ok(self) + } + + fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> { + match *ty.kind() { + // Types without identity. + ty::Bool + | ty::Char + | ty::Int(_) + | ty::Uint(_) + | ty::Float(_) + | ty::Str + | ty::Array(_, _) + | ty::Slice(_) + | ty::RawPtr(_) + | ty::Ref(_, _, _) + | ty::FnPtr(_) + | ty::Never + | ty::Tuple(_) + | ty::Dynamic(_, _) => self.pretty_print_type(ty), + + // Placeholders (all printed as `_` to uniformize them). + ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => { + write!(self, "_")?; + Ok(self) + } + + // Types with identity (print the module path). + ty::Adt(ty::AdtDef(Interned(&ty::AdtDefData { did: def_id, .. }, _)), substs) + | ty::FnDef(def_id, substs) + | ty::Opaque(def_id, substs) + | ty::Projection(ty::ProjectionTy { item_def_id: def_id, substs }) + | ty::Closure(def_id, substs) + | ty::Generator(def_id, substs, _) => self.print_def_path(def_id, substs), + ty::Foreign(def_id) => self.print_def_path(def_id, &[]), + + ty::GeneratorWitness(_) => bug!("type_name: unexpected `GeneratorWitness`"), + } + } + + fn print_const(self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> { + self.pretty_print_const(ct, false) + } + + fn print_dyn_existential( + mut self, + predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>, + ) -> Result<Self::DynExistential, Self::Error> { + let mut first = true; + for p in predicates { + if !first { + write!(self, "+")?; + } + first = false; + self = p.print(self)?; + } + Ok(self) + } + + fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> { + self.path.push_str(self.tcx.crate_name(cnum).as_str()); + Ok(self) + } + + fn path_qualified( + self, + self_ty: Ty<'tcx>, + trait_ref: Option<ty::TraitRef<'tcx>>, + ) -> Result<Self::Path, Self::Error> { + self.pretty_path_qualified(self_ty, trait_ref) + } + + fn path_append_impl( + self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + _disambiguated_data: &DisambiguatedDefPathData, + self_ty: Ty<'tcx>, + trait_ref: Option<ty::TraitRef<'tcx>>, + ) -> Result<Self::Path, Self::Error> { + self.pretty_path_append_impl( + |mut cx| { + cx = print_prefix(cx)?; + + cx.path.push_str("::"); + + Ok(cx) + }, + self_ty, + trait_ref, + ) + } + + fn path_append( + mut self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + disambiguated_data: &DisambiguatedDefPathData, + ) -> Result<Self::Path, Self::Error> { + self = print_prefix(self)?; + + write!(self.path, "::{}", disambiguated_data.data).unwrap(); + + Ok(self) + } + + fn path_generic_args( + mut self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + args: &[GenericArg<'tcx>], + ) -> Result<Self::Path, Self::Error> { + self = print_prefix(self)?; + let args = + args.iter().cloned().filter(|arg| !matches!(arg.unpack(), GenericArgKind::Lifetime(_))); + if args.clone().next().is_some() { + self.generic_delimiters(|cx| cx.comma_sep(args)) + } else { + Ok(self) + } + } +} + +impl<'tcx> PrettyPrinter<'tcx> for AbsolutePathPrinter<'tcx> { + fn should_print_region(&self, _region: ty::Region<'_>) -> bool { + false + } + fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, Self::Error> + where + T: Print<'tcx, Self, Output = Self, Error = Self::Error>, + { + if let Some(first) = elems.next() { + self = first.print(self)?; + for elem in elems { + self.path.push_str(", "); + self = elem.print(self)?; + } + } + Ok(self) + } + + fn generic_delimiters( + mut self, + f: impl FnOnce(Self) -> Result<Self, Self::Error>, + ) -> Result<Self, Self::Error> { + write!(self, "<")?; + + self = f(self)?; + + write!(self, ">")?; + + Ok(self) + } +} + +impl Write for AbsolutePathPrinter<'_> { + fn write_str(&mut self, s: &str) -> std::fmt::Result { + self.path.push_str(s); + Ok(()) + } +} + +/// Directly returns an `Allocation` containing an absolute path representation of the given type. +pub(crate) fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ConstAllocation<'tcx> { + let path = AbsolutePathPrinter { tcx, path: String::new() }.print_type(ty).unwrap().path; + let alloc = Allocation::from_bytes_byte_aligned_immutable(path.into_bytes()); + tcx.intern_const_alloc(alloc) +} |