From 698f8c2f01ea549d77d7dc3338a12e04c11057b9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 17 Apr 2024 14:02:58 +0200 Subject: Adding upstream version 1.64.0+dfsg1. Signed-off-by: Daniel Baumann --- compiler/rustc_symbol_mangling/src/v0.rs | 844 +++++++++++++++++++++++++++++++ 1 file changed, 844 insertions(+) create mode 100644 compiler/rustc_symbol_mangling/src/v0.rs (limited to 'compiler/rustc_symbol_mangling/src/v0.rs') diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs new file mode 100644 index 000000000..71fa5a448 --- /dev/null +++ b/compiler/rustc_symbol_mangling/src/v0.rs @@ -0,0 +1,844 @@ +use rustc_data_structures::base_n; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_data_structures::intern::Interned; +use rustc_hir as hir; +use rustc_hir::def::CtorKind; +use rustc_hir::def_id::{CrateNum, DefId}; +use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData}; +use rustc_middle::ty::layout::IntegerExt; +use rustc_middle::ty::print::{Print, Printer}; +use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst}; +use rustc_middle::ty::{ + self, EarlyBinder, FloatTy, Instance, IntTy, Ty, TyCtxt, TypeVisitable, UintTy, +}; +use rustc_span::symbol::kw; +use rustc_target::abi::Integer; +use rustc_target::spec::abi::Abi; + +use std::fmt::Write; +use std::iter; +use std::ops::Range; + +pub(super) fn mangle<'tcx>( + tcx: TyCtxt<'tcx>, + instance: Instance<'tcx>, + instantiating_crate: Option, +) -> String { + let def_id = instance.def_id(); + // FIXME(eddyb) this should ideally not be needed. + let substs = tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), instance.substs); + + let prefix = "_R"; + let mut cx = &mut SymbolMangler { + tcx, + start_offset: prefix.len(), + paths: FxHashMap::default(), + types: FxHashMap::default(), + consts: FxHashMap::default(), + binders: vec![], + out: String::from(prefix), + }; + + // Append `::{shim:...#0}` to shims that can coexist with a non-shim instance. + let shim_kind = match instance.def { + ty::InstanceDef::VTableShim(_) => Some("vtable"), + ty::InstanceDef::ReifyShim(_) => Some("reify"), + + _ => None, + }; + + cx = if let Some(shim_kind) = shim_kind { + cx.path_append_ns(|cx| cx.print_def_path(def_id, substs), 'S', 0, shim_kind).unwrap() + } else { + cx.print_def_path(def_id, substs).unwrap() + }; + if let Some(instantiating_crate) = instantiating_crate { + cx = cx.print_def_path(instantiating_crate.as_def_id(), &[]).unwrap(); + } + std::mem::take(&mut cx.out) +} + +pub(super) fn mangle_typeid_for_trait_ref<'tcx>( + tcx: TyCtxt<'tcx>, + trait_ref: ty::PolyExistentialTraitRef<'tcx>, +) -> String { + // FIXME(flip1995): See comment in `mangle_typeid_for_fnabi`. + let mut cx = &mut SymbolMangler { + tcx, + start_offset: 0, + paths: FxHashMap::default(), + types: FxHashMap::default(), + consts: FxHashMap::default(), + binders: vec![], + out: String::new(), + }; + cx = cx.print_def_path(trait_ref.def_id(), &[]).unwrap(); + std::mem::take(&mut cx.out) +} + +struct BinderLevel { + /// The range of distances from the root of what's + /// being printed, to the lifetimes in a binder. + /// Specifically, a `BrAnon(i)` lifetime has depth + /// `lifetime_depths.start + i`, going away from the + /// the root and towards its use site, as `i` increases. + /// This is used to flatten rustc's pairing of `BrAnon` + /// (intra-binder disambiguation) with a `DebruijnIndex` + /// (binder addressing), to "true" de Bruijn indices, + /// by subtracting the depth of a certain lifetime, from + /// the innermost depth at its use site. + lifetime_depths: Range, +} + +struct SymbolMangler<'tcx> { + tcx: TyCtxt<'tcx>, + binders: Vec, + out: String, + + /// The length of the prefix in `out` (e.g. 2 for `_R`). + start_offset: usize, + /// The values are start positions in `out`, in bytes. + paths: FxHashMap<(DefId, &'tcx [GenericArg<'tcx>]), usize>, + types: FxHashMap, usize>, + consts: FxHashMap, usize>, +} + +impl<'tcx> SymbolMangler<'tcx> { + fn push(&mut self, s: &str) { + self.out.push_str(s); + } + + /// Push a `_`-terminated base 62 integer, using the format + /// specified in the RFC as ``, that is: + /// * `x = 0` is encoded as just the `"_"` terminator + /// * `x > 0` is encoded as `x - 1` in base 62, followed by `"_"`, + /// e.g. `1` becomes `"0_"`, `62` becomes `"Z_"`, etc. + fn push_integer_62(&mut self, x: u64) { + if let Some(x) = x.checked_sub(1) { + base_n::push_str(x as u128, 62, &mut self.out); + } + self.push("_"); + } + + /// Push a `tag`-prefixed base 62 integer, when larger than `0`, that is: + /// * `x = 0` is encoded as `""` (nothing) + /// * `x > 0` is encoded as the `tag` followed by `push_integer_62(x - 1)` + /// e.g. `1` becomes `tag + "_"`, `2` becomes `tag + "0_"`, etc. + fn push_opt_integer_62(&mut self, tag: &str, x: u64) { + if let Some(x) = x.checked_sub(1) { + self.push(tag); + self.push_integer_62(x); + } + } + + fn push_disambiguator(&mut self, dis: u64) { + self.push_opt_integer_62("s", dis); + } + + fn push_ident(&mut self, ident: &str) { + let mut use_punycode = false; + for b in ident.bytes() { + match b { + b'_' | b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' => {} + 0x80..=0xff => use_punycode = true, + _ => bug!("symbol_names: bad byte {} in ident {:?}", b, ident), + } + } + + let punycode_string; + let ident = if use_punycode { + self.push("u"); + + // FIXME(eddyb) we should probably roll our own punycode implementation. + let mut punycode_bytes = match punycode::encode(ident) { + Ok(s) => s.into_bytes(), + Err(()) => bug!("symbol_names: punycode encoding failed for ident {:?}", ident), + }; + + // Replace `-` with `_`. + if let Some(c) = punycode_bytes.iter_mut().rfind(|&&mut c| c == b'-') { + *c = b'_'; + } + + // FIXME(eddyb) avoid rechecking UTF-8 validity. + punycode_string = String::from_utf8(punycode_bytes).unwrap(); + &punycode_string + } else { + ident + }; + + let _ = write!(self.out, "{}", ident.len()); + + // Write a separating `_` if necessary (leading digit or `_`). + if let Some('_' | '0'..='9') = ident.chars().next() { + self.push("_"); + } + + self.push(ident); + } + + fn path_append_ns<'a>( + mut self: &'a mut Self, + print_prefix: impl FnOnce(&'a mut Self) -> Result<&'a mut Self, !>, + ns: char, + disambiguator: u64, + name: &str, + ) -> Result<&'a mut Self, !> { + self.push("N"); + self.out.push(ns); + self = print_prefix(self)?; + self.push_disambiguator(disambiguator as u64); + self.push_ident(name); + Ok(self) + } + + fn print_backref(&mut self, i: usize) -> Result<&mut Self, !> { + self.push("B"); + self.push_integer_62((i - self.start_offset) as u64); + Ok(self) + } + + fn in_binder<'a, T>( + mut self: &'a mut Self, + value: &ty::Binder<'tcx, T>, + print_value: impl FnOnce(&'a mut Self, &T) -> Result<&'a mut Self, !>, + ) -> Result<&'a mut Self, !> + where + T: TypeVisitable<'tcx>, + { + let regions = if value.has_late_bound_regions() { + self.tcx.collect_referenced_late_bound_regions(value) + } else { + FxHashSet::default() + }; + + let mut lifetime_depths = + self.binders.last().map(|b| b.lifetime_depths.end).map_or(0..0, |i| i..i); + + let lifetimes = regions + .into_iter() + .map(|br| match br { + ty::BrAnon(i) => i, + _ => bug!("symbol_names: non-anonymized region `{:?}` in `{:?}`", br, value), + }) + .max() + .map_or(0, |max| max + 1); + + self.push_opt_integer_62("G", lifetimes as u64); + lifetime_depths.end += lifetimes; + + self.binders.push(BinderLevel { lifetime_depths }); + self = print_value(self, value.as_ref().skip_binder())?; + self.binders.pop(); + + Ok(self) + } +} + +impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> { + type 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_def_path( + mut self, + def_id: DefId, + substs: &'tcx [GenericArg<'tcx>], + ) -> Result { + if let Some(&i) = self.paths.get(&(def_id, substs)) { + return self.print_backref(i); + } + let start = self.out.len(); + + self = self.default_print_def_path(def_id, substs)?; + + // Only cache paths that do not refer to an enclosing + // binder (which would change depending on context). + if !substs.iter().any(|k| k.has_escaping_bound_vars()) { + self.paths.insert((def_id, substs), start); + } + Ok(self) + } + + fn print_impl_path( + mut self, + impl_def_id: DefId, + substs: &'tcx [GenericArg<'tcx>], + mut self_ty: Ty<'tcx>, + mut impl_trait_ref: Option>, + ) -> Result { + let key = self.tcx.def_key(impl_def_id); + let parent_def_id = DefId { index: key.parent.unwrap(), ..impl_def_id }; + + let mut param_env = self.tcx.param_env_reveal_all_normalized(impl_def_id); + if !substs.is_empty() { + param_env = EarlyBinder(param_env).subst(self.tcx, substs); + } + + match &mut impl_trait_ref { + Some(impl_trait_ref) => { + assert_eq!(impl_trait_ref.self_ty(), self_ty); + *impl_trait_ref = self.tcx.normalize_erasing_regions(param_env, *impl_trait_ref); + self_ty = impl_trait_ref.self_ty(); + } + None => { + self_ty = self.tcx.normalize_erasing_regions(param_env, self_ty); + } + } + + self.push(match impl_trait_ref { + Some(_) => "X", + None => "M", + }); + + // Encode impl generic params if the substitutions contain parameters (implying + // polymorphization is enabled) and this isn't an inherent impl. + if impl_trait_ref.is_some() && substs.iter().any(|a| a.has_param_types_or_consts()) { + self = self.path_generic_args( + |this| { + this.path_append_ns( + |cx| cx.print_def_path(parent_def_id, &[]), + 'I', + key.disambiguated_data.disambiguator as u64, + "", + ) + }, + substs, + )?; + } else { + self.push_disambiguator(key.disambiguated_data.disambiguator as u64); + self = self.print_def_path(parent_def_id, &[])?; + } + + self = self_ty.print(self)?; + + if let Some(trait_ref) = impl_trait_ref { + self = self.print_def_path(trait_ref.def_id, trait_ref.substs)?; + } + + Ok(self) + } + + fn print_region(self, region: ty::Region<'_>) -> Result { + let i = match *region { + // Erased lifetimes use the index 0, for a + // shorter mangling of `L_`. + ty::ReErased => 0, + + // Late-bound lifetimes use indices starting at 1, + // see `BinderLevel` for more details. + ty::ReLateBound(debruijn, ty::BoundRegion { kind: ty::BrAnon(i), .. }) => { + let binder = &self.binders[self.binders.len() - 1 - debruijn.index()]; + let depth = binder.lifetime_depths.start + i; + + 1 + (self.binders.last().unwrap().lifetime_depths.end - 1 - depth) + } + + _ => bug!("symbol_names: non-erased region `{:?}`", region), + }; + self.push("L"); + self.push_integer_62(i as u64); + Ok(self) + } + + fn print_type(mut self, ty: Ty<'tcx>) -> Result { + // Basic types, never cached (single-character). + let basic_type = match ty.kind() { + ty::Bool => "b", + ty::Char => "c", + ty::Str => "e", + ty::Tuple(_) if ty.is_unit() => "u", + ty::Int(IntTy::I8) => "a", + ty::Int(IntTy::I16) => "s", + ty::Int(IntTy::I32) => "l", + ty::Int(IntTy::I64) => "x", + ty::Int(IntTy::I128) => "n", + ty::Int(IntTy::Isize) => "i", + ty::Uint(UintTy::U8) => "h", + ty::Uint(UintTy::U16) => "t", + ty::Uint(UintTy::U32) => "m", + ty::Uint(UintTy::U64) => "y", + ty::Uint(UintTy::U128) => "o", + ty::Uint(UintTy::Usize) => "j", + ty::Float(FloatTy::F32) => "f", + ty::Float(FloatTy::F64) => "d", + ty::Never => "z", + + // Placeholders (should be demangled as `_`). + ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => "p", + + _ => "", + }; + if !basic_type.is_empty() { + self.push(basic_type); + return Ok(self); + } + + if let Some(&i) = self.types.get(&ty) { + return self.print_backref(i); + } + let start = self.out.len(); + + match *ty.kind() { + // Basic types, handled above. + ty::Bool | ty::Char | ty::Str | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Never => { + unreachable!() + } + ty::Tuple(_) if ty.is_unit() => unreachable!(), + + // Placeholders, also handled as part of basic types. + ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => { + unreachable!() + } + + ty::Ref(r, ty, mutbl) => { + self.push(match mutbl { + hir::Mutability::Not => "R", + hir::Mutability::Mut => "Q", + }); + if !r.is_erased() { + self = r.print(self)?; + } + self = ty.print(self)?; + } + + ty::RawPtr(mt) => { + self.push(match mt.mutbl { + hir::Mutability::Not => "P", + hir::Mutability::Mut => "O", + }); + self = mt.ty.print(self)?; + } + + ty::Array(ty, len) => { + self.push("A"); + self = ty.print(self)?; + self = self.print_const(len)?; + } + ty::Slice(ty) => { + self.push("S"); + self = ty.print(self)?; + } + + ty::Tuple(tys) => { + self.push("T"); + for ty in tys.iter() { + self = ty.print(self)?; + } + self.push("E"); + } + + // Mangle all nominal types as paths. + 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 = self.print_def_path(def_id, substs)?; + } + ty::Foreign(def_id) => { + self = self.print_def_path(def_id, &[])?; + } + + ty::FnPtr(sig) => { + self.push("F"); + self = self.in_binder(&sig, |mut cx, sig| { + if sig.unsafety == hir::Unsafety::Unsafe { + cx.push("U"); + } + match sig.abi { + Abi::Rust => {} + Abi::C { unwind: false } => cx.push("KC"), + abi => { + cx.push("K"); + let name = abi.name(); + if name.contains('-') { + cx.push_ident(&name.replace('-', "_")); + } else { + cx.push_ident(name); + } + } + } + for &ty in sig.inputs() { + cx = ty.print(cx)?; + } + if sig.c_variadic { + cx.push("v"); + } + cx.push("E"); + sig.output().print(cx) + })?; + } + + ty::Dynamic(predicates, r) => { + self.push("D"); + self = self.print_dyn_existential(predicates)?; + self = r.print(self)?; + } + + ty::GeneratorWitness(_) => bug!("symbol_names: unexpected `GeneratorWitness`"), + } + + // Only cache types that do not refer to an enclosing + // binder (which would change depending on context). + if !ty.has_escaping_bound_vars() { + self.types.insert(ty, start); + } + Ok(self) + } + + fn print_dyn_existential( + mut self, + predicates: &'tcx ty::List>>, + ) -> Result { + // Okay, so this is a bit tricky. Imagine we have a trait object like + // `dyn for<'a> Foo<'a, Bar = &'a ()>`. When we mangle this, the + // output looks really close to the syntax, where the `Bar = &'a ()` bit + // is under the same binders (`['a]`) as the `Foo<'a>` bit. However, we + // actually desugar these into two separate `ExistentialPredicate`s. We + // can't enter/exit the "binder scope" twice though, because then we + // would mangle the binders twice. (Also, side note, we merging these + // two is kind of difficult, because of potential HRTBs in the Projection + // predicate.) + // + // Also worth mentioning: imagine that we instead had + // `dyn for<'a> Foo<'a, Bar = &'a ()> + Send`. In this case, `Send` is + // under the same binders as `Foo`. Currently, this doesn't matter, + // because only *auto traits* are allowed other than the principal trait + // and all auto traits don't have any generics. Two things could + // make this not an "okay" mangling: + // 1) Instead of mangling only *used* + // bound vars, we want to mangle *all* bound vars (`for<'b> Send` is a + // valid trait predicate); + // 2) We allow multiple "principal" traits in the future, or at least + // allow in any form another trait predicate that can take generics. + // + // Here we assume that predicates have the following structure: + // [ [{}]] [{}] + // Since any predicates after the first one shouldn't change the binders, + // just put them all in the binders of the first. + self = self.in_binder(&predicates[0], |mut cx, _| { + for predicate in predicates.iter() { + // It would be nice to be able to validate bound vars here, but + // projections can actually include bound vars from super traits + // because of HRTBs (only in the `Self` type). Also, auto traits + // could have different bound vars *anyways*. + match predicate.as_ref().skip_binder() { + ty::ExistentialPredicate::Trait(trait_ref) => { + // Use a type that can't appear in defaults of type parameters. + let dummy_self = cx.tcx.mk_ty_infer(ty::FreshTy(0)); + let trait_ref = trait_ref.with_self_ty(cx.tcx, dummy_self); + cx = cx.print_def_path(trait_ref.def_id, trait_ref.substs)?; + } + ty::ExistentialPredicate::Projection(projection) => { + let name = cx.tcx.associated_item(projection.item_def_id).name; + cx.push("p"); + cx.push_ident(name.as_str()); + cx = match projection.term { + ty::Term::Ty(ty) => ty.print(cx), + ty::Term::Const(c) => c.print(cx), + }?; + } + ty::ExistentialPredicate::AutoTrait(def_id) => { + cx = cx.print_def_path(*def_id, &[])?; + } + } + } + Ok(cx) + })?; + + self.push("E"); + Ok(self) + } + + fn print_const(mut self, ct: ty::Const<'tcx>) -> Result { + // We only mangle a typed value if the const can be evaluated. + let ct = ct.eval(self.tcx, ty::ParamEnv::reveal_all()); + match ct.kind() { + ty::ConstKind::Value(_) => {} + + // Placeholders (should be demangled as `_`). + // NOTE(eddyb) despite `Unevaluated` having a `DefId` (and therefore + // a path), even for it we still need to encode a placeholder, as + // the path could refer back to e.g. an `impl` using the constant. + ty::ConstKind::Unevaluated(_) + | ty::ConstKind::Param(_) + | ty::ConstKind::Infer(_) + | ty::ConstKind::Bound(..) + | ty::ConstKind::Placeholder(_) + | ty::ConstKind::Error(_) => { + // Never cached (single-character). + self.push("p"); + return Ok(self); + } + } + + if let Some(&i) = self.consts.get(&ct) { + return self.print_backref(i); + } + + let start = self.out.len(); + let ty = ct.ty(); + + match ty.kind() { + ty::Uint(_) | ty::Int(_) | ty::Bool | ty::Char => { + self = ty.print(self)?; + + let mut bits = ct.eval_bits(self.tcx, ty::ParamEnv::reveal_all(), ty); + + // Negative integer values are mangled using `n` as a "sign prefix". + if let ty::Int(ity) = ty.kind() { + let val = + Integer::from_int_ty(&self.tcx, *ity).size().sign_extend(bits) as i128; + if val < 0 { + self.push("n"); + } + bits = val.unsigned_abs(); + } + + let _ = write!(self.out, "{:x}_", bits); + } + + // FIXME(valtrees): Remove the special case for `str` + // here and fully support unsized constants. + ty::Ref(_, inner_ty, mutbl) => { + self.push(match mutbl { + hir::Mutability::Not => "R", + hir::Mutability::Mut => "Q", + }); + + match inner_ty.kind() { + ty::Str if *mutbl == hir::Mutability::Not => { + match ct.kind() { + ty::ConstKind::Value(valtree) => { + let slice = + valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| { + bug!( + "expected to get raw bytes from valtree {:?} for type {:}", + valtree, ty + ) + }); + let s = std::str::from_utf8(slice).expect("non utf8 str from miri"); + + self.push("e"); + + // FIXME(eddyb) use a specialized hex-encoding loop. + for byte in s.bytes() { + let _ = write!(self.out, "{:02x}", byte); + } + + self.push("_"); + } + + _ => { + bug!("symbol_names: unsupported `&str` constant: {:?}", ct); + } + } + } + _ => { + let pointee_ty = ct + .ty() + .builtin_deref(true) + .expect("tried to dereference on non-ptr type") + .ty; + let dereferenced_const = + self.tcx.mk_const(ty::ConstS { kind: ct.kind(), ty: pointee_ty }); + self = dereferenced_const.print(self)?; + } + } + } + + ty::Array(..) | ty::Tuple(..) | ty::Adt(..) | ty::Slice(_) => { + let contents = self.tcx.destructure_const(ct); + let fields = contents.fields.iter().copied(); + + let print_field_list = |mut this: Self| { + for field in fields.clone() { + this = field.print(this)?; + } + this.push("E"); + Ok(this) + }; + + match *ct.ty().kind() { + ty::Array(..) | ty::Slice(_) => { + self.push("A"); + self = print_field_list(self)?; + } + ty::Tuple(..) => { + self.push("T"); + self = print_field_list(self)?; + } + ty::Adt(def, substs) => { + let variant_idx = + contents.variant.expect("destructed const of adt without variant idx"); + let variant_def = &def.variant(variant_idx); + + self.push("V"); + self = self.print_def_path(variant_def.def_id, substs)?; + + match variant_def.ctor_kind { + CtorKind::Const => { + self.push("U"); + } + CtorKind::Fn => { + self.push("T"); + self = print_field_list(self)?; + } + CtorKind::Fictive => { + self.push("S"); + for (field_def, field) in iter::zip(&variant_def.fields, fields) { + // HACK(eddyb) this mimics `path_append`, + // instead of simply using `field_def.ident`, + // just to be able to handle disambiguators. + let disambiguated_field = + self.tcx.def_key(field_def.did).disambiguated_data; + let field_name = disambiguated_field.data.get_opt_name(); + self.push_disambiguator( + disambiguated_field.disambiguator as u64, + ); + self.push_ident(field_name.unwrap_or(kw::Empty).as_str()); + + self = field.print(self)?; + } + self.push("E"); + } + } + } + _ => unreachable!(), + } + } + _ => { + bug!("symbol_names: unsupported constant of type `{}` ({:?})", ct.ty(), ct); + } + } + + // Only cache consts that do not refer to an enclosing + // binder (which would change depending on context). + if !ct.has_escaping_bound_vars() { + self.consts.insert(ct, start); + } + Ok(self) + } + + fn path_crate(self, cnum: CrateNum) -> Result { + self.push("C"); + let stable_crate_id = self.tcx.def_path_hash(cnum.as_def_id()).stable_crate_id(); + self.push_disambiguator(stable_crate_id.to_u64()); + let name = self.tcx.crate_name(cnum); + self.push_ident(name.as_str()); + Ok(self) + } + + fn path_qualified( + mut self, + self_ty: Ty<'tcx>, + trait_ref: Option>, + ) -> Result { + assert!(trait_ref.is_some()); + let trait_ref = trait_ref.unwrap(); + + self.push("Y"); + self = self_ty.print(self)?; + self.print_def_path(trait_ref.def_id, trait_ref.substs) + } + + fn path_append_impl( + self, + _: impl FnOnce(Self) -> Result, + _: &DisambiguatedDefPathData, + _: Ty<'tcx>, + _: Option>, + ) -> Result { + // Inlined into `print_impl_path` + unreachable!() + } + + fn path_append( + self, + print_prefix: impl FnOnce(Self) -> Result, + disambiguated_data: &DisambiguatedDefPathData, + ) -> Result { + let ns = match disambiguated_data.data { + // Extern block segments can be skipped, names from extern blocks + // are effectively living in their parent modules. + DefPathData::ForeignMod => return print_prefix(self), + + // Uppercase categories are more stable than lowercase ones. + DefPathData::TypeNs(_) => 't', + DefPathData::ValueNs(_) => 'v', + DefPathData::ClosureExpr => 'C', + DefPathData::Ctor => 'c', + DefPathData::AnonConst => 'k', + DefPathData::ImplTrait => 'i', + + // These should never show up as `path_append` arguments. + DefPathData::CrateRoot + | DefPathData::Use + | DefPathData::GlobalAsm + | DefPathData::Impl + | DefPathData::MacroNs(_) + | DefPathData::LifetimeNs(_) => { + bug!("symbol_names: unexpected DefPathData: {:?}", disambiguated_data.data) + } + }; + + let name = disambiguated_data.data.get_opt_name(); + + self.path_append_ns( + print_prefix, + ns, + disambiguated_data.disambiguator as u64, + name.unwrap_or(kw::Empty).as_str(), + ) + } + + fn path_generic_args( + mut self, + print_prefix: impl FnOnce(Self) -> Result, + args: &[GenericArg<'tcx>], + ) -> Result { + // Don't print any regions if they're all erased. + let print_regions = args.iter().any(|arg| match arg.unpack() { + GenericArgKind::Lifetime(r) => !r.is_erased(), + _ => false, + }); + let args = args.iter().cloned().filter(|arg| match arg.unpack() { + GenericArgKind::Lifetime(_) => print_regions, + _ => true, + }); + + if args.clone().next().is_none() { + return print_prefix(self); + } + + self.push("I"); + self = print_prefix(self)?; + for arg in args { + match arg.unpack() { + GenericArgKind::Lifetime(lt) => { + self = lt.print(self)?; + } + GenericArgKind::Type(ty) => { + self = ty.print(self)?; + } + GenericArgKind::Const(c) => { + self.push("K"); + self = c.print(self)?; + } + } + } + self.push("E"); + + Ok(self) + } +} -- cgit v1.2.3