diff options
Diffstat (limited to 'compiler/rustc_symbol_mangling/src/v0.rs')
| -rw-r--r-- | compiler/rustc_symbol_mangling/src/v0.rs | 647 |
1 files changed, 647 insertions, 0 deletions
diff --git a/compiler/rustc_symbol_mangling/src/v0.rs b/compiler/rustc_symbol_mangling/src/v0.rs new file mode 100644 index 00000000000..f01c3da8b5f --- /dev/null +++ b/compiler/rustc_symbol_mangling/src/v0.rs @@ -0,0 +1,647 @@ +use rustc_ast::{FloatTy, IntTy, UintTy}; +use rustc_data_structures::base_n; +use rustc_data_structures::fx::{FxHashMap, FxHashSet}; +use rustc_hir as hir; +use rustc_hir::def_id::{CrateNum, DefId}; +use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData}; +use rustc_middle::ty::print::{Print, Printer}; +use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst}; +use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeFoldable}; +use rustc_target::spec::abi::Abi; + +use std::fmt::Write; +use std::ops::Range; + +pub(super) fn mangle( + tcx: TyCtxt<'tcx>, + instance: Instance<'tcx>, + instantiating_crate: Option<CrateNum>, +) -> 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 = SymbolMangler { + tcx, + compress: Some(Box::new(CompressionCaches { + 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(); + } + cx.out +} + +struct CompressionCaches<'tcx> { + // 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<Ty<'tcx>, usize>, + consts: FxHashMap<&'tcx ty::Const<'tcx>, usize>, +} + +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<u32>, +} + +struct SymbolMangler<'tcx> { + tcx: TyCtxt<'tcx>, + compress: Option<Box<CompressionCaches<'tcx>>>, + binders: Vec<BinderLevel>, + out: String, +} + +impl 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 `<base-62-number>`, 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 `_`). + match ident.chars().next() { + Some('_' | '0'..='9') => { + self.push("_"); + } + _ => {} + } + + self.push(ident); + } + + fn path_append_ns( + mut self, + print_prefix: impl FnOnce(Self) -> Result<Self, !>, + ns: char, + disambiguator: u64, + name: &str, + ) -> Result<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<Self, !> { + self.push("B"); + self.push_integer_62((i - self.compress.as_ref().unwrap().start_offset) as u64); + Ok(self) + } + + fn in_binder<T>( + mut self, + value: &ty::Binder<T>, + print_value: impl FnOnce(Self, &T) -> Result<Self, !>, + ) -> Result<Self, !> + where + T: TypeFoldable<'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) => { + // FIXME(eddyb) for some reason, `anonymize_late_bound_regions` starts at `1`. + assert_ne!(i, 0); + i - 1 + } + _ => 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 Printer<'tcx> for 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<Self::Path, Self::Error> { + if let Some(&i) = self.compress.as_ref().and_then(|c| c.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()) { + if let Some(c) = &mut self.compress { + c.paths.insert((def_id, substs), start); + } + } + Ok(self) + } + + fn print_impl_path( + self, + impl_def_id: DefId, + substs: &'tcx [GenericArg<'tcx>], + mut self_ty: Ty<'tcx>, + mut impl_trait_ref: Option<ty::TraitRef<'tcx>>, + ) -> Result<Self::Path, Self::Error> { + 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 = 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.path_append_impl( + |cx| cx.print_def_path(parent_def_id, &[]), + &key.disambiguated_data, + self_ty, + impl_trait_ref, + ) + } + + fn print_region(mut self, region: ty::Region<'_>) -> Result<Self::Region, Self::Error> { + 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::BrAnon(i)) => { + // FIXME(eddyb) for some reason, `anonymize_late_bound_regions` starts at `1`. + assert_ne!(i, 0); + let i = i - 1; + + 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<Self::Type, Self::Error> { + // 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.compress.as_ref().and_then(|c| c.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 != ty::ReErased { + 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().map(|k| k.expect_ty()) { + self = ty.print(self)?; + } + self.push("E"); + } + + // Mangle all nominal types as paths. + ty::Adt(&ty::AdtDef { 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 => 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.in_binder(&predicates, |cx, predicates| { + cx.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() { + if let Some(c) = &mut self.compress { + c.types.insert(ty, start); + } + } + Ok(self) + } + + fn print_dyn_existential( + mut self, + predicates: &'tcx ty::List<ty::ExistentialPredicate<'tcx>>, + ) -> Result<Self::DynExistential, Self::Error> { + for predicate in predicates { + match predicate { + ty::ExistentialPredicate::Trait(trait_ref) => { + // Use a type that can't appear in defaults of type parameters. + let dummy_self = self.tcx.mk_ty_infer(ty::FreshTy(0)); + let trait_ref = trait_ref.with_self_ty(self.tcx, dummy_self); + self = self.print_def_path(trait_ref.def_id, trait_ref.substs)?; + } + ty::ExistentialPredicate::Projection(projection) => { + let name = self.tcx.associated_item(projection.item_def_id).ident; + self.push("p"); + self.push_ident(&name.as_str()); + self = projection.ty.print(self)?; + } + ty::ExistentialPredicate::AutoTrait(def_id) => { + self = self.print_def_path(def_id, &[])?; + } + } + } + self.push("E"); + Ok(self) + } + + fn print_const(mut self, ct: &'tcx ty::Const<'tcx>) -> Result<Self::Const, Self::Error> { + if let Some(&i) = self.compress.as_ref().and_then(|c| c.consts.get(&ct)) { + return self.print_backref(i); + } + let start = self.out.len(); + + match ct.ty.kind { + ty::Uint(_) => {} + _ => { + bug!("symbol_names: unsupported constant of type `{}` ({:?})", ct.ty, ct); + } + } + self = ct.ty.print(self)?; + + if let Some(bits) = ct.try_eval_bits(self.tcx, ty::ParamEnv::reveal_all(), ct.ty) { + let _ = write!(self.out, "{:x}_", bits); + } else { + // NOTE(eddyb) despite having the path, we need to + // encode a placeholder, as the path could refer + // back to e.g. an `impl` using the constant. + self.push("p"); + } + + // Only cache consts that do not refer to an enclosing + // binder (which would change depending on context). + if !ct.has_escaping_bound_vars() { + if let Some(c) = &mut self.compress { + c.consts.insert(ct, start); + } + } + Ok(self) + } + + fn path_crate(mut self, cnum: CrateNum) -> Result<Self::Path, Self::Error> { + self.push("C"); + let fingerprint = self.tcx.crate_disambiguator(cnum).to_fingerprint(); + self.push_disambiguator(fingerprint.to_smaller_hash()); + let name = self.tcx.original_crate_name(cnum).as_str(); + self.push_ident(&name); + Ok(self) + } + fn path_qualified( + mut self, + self_ty: Ty<'tcx>, + trait_ref: Option<ty::TraitRef<'tcx>>, + ) -> Result<Self::Path, Self::Error> { + 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( + mut 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.push(match trait_ref { + Some(_) => "X", + None => "M", + }); + self.push_disambiguator(disambiguated_data.disambiguator as u64); + self = print_prefix(self)?; + self = self_ty.print(self)?; + if let Some(trait_ref) = trait_ref { + self = self.print_def_path(trait_ref.def_id, trait_ref.substs)?; + } + Ok(self) + } + fn path_append( + self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + disambiguated_data: &DisambiguatedDefPathData, + ) -> Result<Self::Path, Self::Error> { + let ns = match disambiguated_data.data { + // 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::Misc + | DefPathData::Impl + | DefPathData::MacroNs(_) + | DefPathData::LifetimeNs(_) => { + bug!("symbol_names: unexpected DefPathData: {:?}", disambiguated_data.data) + } + }; + + let name = disambiguated_data.data.get_opt_name().map(|s| s.as_str()); + + self.path_append_ns( + print_prefix, + ns, + disambiguated_data.disambiguator as u64, + name.as_ref().map_or("", |s| &s[..]), + ) + } + fn path_generic_args( + mut self, + print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, + args: &[GenericArg<'tcx>], + ) -> Result<Self::Path, Self::Error> { + // Don't print any regions if they're all erased. + let print_regions = args.iter().any(|arg| match arg.unpack() { + GenericArgKind::Lifetime(r) => *r != ty::ReErased, + _ => 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) + } +} |