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Diffstat (limited to 'compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs')
| -rw-r--r-- | compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs | 929 |
1 files changed, 929 insertions, 0 deletions
diff --git a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs new file mode 100644 index 000000000..a09b52fbf --- /dev/null +++ b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs @@ -0,0 +1,929 @@ +// For more information about type metadata and type metadata identifiers for cross-language LLVM +// CFI support, see Type metadata in the design document in the tracking issue #89653. + +// FIXME(rcvalle): Identify C char and integer type uses and encode them with their respective +// builtin type encodings as specified by the Itanium C++ ABI for extern function types with the "C" +// calling convention to use this encoding for cross-language LLVM CFI. + +use bitflags::bitflags; +use core::fmt::Display; +use rustc_data_structures::base_n; +use rustc_data_structures::fx::FxHashMap; +use rustc_hir as hir; +use rustc_middle::ty::subst::{GenericArg, GenericArgKind, SubstsRef}; +use rustc_middle::ty::{ + self, Binder, Const, ExistentialPredicate, FloatTy, FnSig, IntTy, List, Region, RegionKind, + Term, Ty, TyCtxt, UintTy, +}; +use rustc_span::def_id::DefId; +use rustc_span::symbol::sym; +use rustc_target::abi::call::{Conv, FnAbi}; +use rustc_target::spec::abi::Abi; +use std::fmt::Write as _; + +/// Type and extended type qualifiers. +#[derive(Eq, Hash, PartialEq)] +enum TyQ { + None, + Const, + Mut, +} + +/// Substitution dictionary key. +#[derive(Eq, Hash, PartialEq)] +enum DictKey<'tcx> { + Ty(Ty<'tcx>, TyQ), + Region(Region<'tcx>), + Const(Const<'tcx>), + Predicate(ExistentialPredicate<'tcx>), +} + +bitflags! { + /// Options for typeid_for_fnabi and typeid_for_fnsig. + pub struct TypeIdOptions: u32 { + const NO_OPTIONS = 0; + const GENERALIZE_POINTERS = 1; + const GENERALIZE_REPR_C = 2; + } +} + +/// Options for encode_ty. +type EncodeTyOptions = TypeIdOptions; + +/// Options for transform_ty. +type TransformTyOptions = TypeIdOptions; + +/// Converts a number to a disambiguator (see +/// <https://rust-lang.github.io/rfcs/2603-rust-symbol-name-mangling-v0.html>). +fn to_disambiguator(num: u64) -> String { + if let Some(num) = num.checked_sub(1) { + format!("s{}_", base_n::encode(num as u128, 62)) + } else { + "s_".to_string() + } +} + +/// Converts a number to a sequence number (see +/// <https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangle.seq-id>). +fn to_seq_id(num: usize) -> String { + if let Some(num) = num.checked_sub(1) { + base_n::encode(num as u128, 36).to_uppercase() + } else { + "".to_string() + } +} + +/// Substitutes a component if found in the substitution dictionary (see +/// <https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling-compression>). +fn compress<'tcx>( + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + key: DictKey<'tcx>, + comp: &mut String, +) { + match dict.get(&key) { + Some(num) => { + comp.clear(); + let _ = write!(comp, "S{}_", to_seq_id(*num)); + } + None => { + dict.insert(key, dict.len()); + } + } +} + +// FIXME(rcvalle): Move to compiler/rustc_middle/src/ty/sty.rs after C types work is done, possibly +// along with other is_c_type methods. +/// Returns whether a `ty::Ty` is `c_void`. +fn is_c_void_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool { + match ty.kind() { + ty::Adt(adt_def, ..) => { + let def_id = adt_def.0.did; + let crate_name = tcx.crate_name(def_id.krate); + if tcx.item_name(def_id).as_str() == "c_void" + && (crate_name == sym::core || crate_name == sym::std || crate_name == sym::libc) + { + true + } else { + false + } + } + _ => false, + } +} + +/// Encodes a const using the Itanium C++ ABI as a literal argument (see +/// <https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling.literal>). +fn encode_const<'tcx>( + tcx: TyCtxt<'tcx>, + c: Const<'tcx>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + options: EncodeTyOptions, +) -> String { + // L<element-type>[n]<element-value>E as literal argument + let mut s = String::from('L'); + + // Element type + s.push_str(&encode_ty(tcx, c.ty(), dict, options)); + + // The only allowed types of const parameters are bool, u8, u16, u32, u64, u128, usize i8, i16, + // i32, i64, i128, isize, and char. The bool value false is encoded as 0 and true as 1. + fn push_signed_value<T: Display + PartialOrd>(s: &mut String, value: T, zero: T) { + if value < zero { + s.push('n') + }; + let _ = write!(s, "{}", value); + } + + fn push_unsigned_value<T: Display>(s: &mut String, value: T) { + let _ = write!(s, "{}", value); + } + + if let Some(scalar_int) = c.kind().try_to_scalar_int() { + let signed = c.ty().is_signed(); + match scalar_int.size().bits() { + 8 if signed => push_signed_value(&mut s, scalar_int.try_to_i8().unwrap(), 0), + 16 if signed => push_signed_value(&mut s, scalar_int.try_to_i16().unwrap(), 0), + 32 if signed => push_signed_value(&mut s, scalar_int.try_to_i32().unwrap(), 0), + 64 if signed => push_signed_value(&mut s, scalar_int.try_to_i64().unwrap(), 0), + 128 if signed => push_signed_value(&mut s, scalar_int.try_to_i128().unwrap(), 0), + 8 => push_unsigned_value(&mut s, scalar_int.try_to_u8().unwrap()), + 16 => push_unsigned_value(&mut s, scalar_int.try_to_u16().unwrap()), + 32 => push_unsigned_value(&mut s, scalar_int.try_to_u32().unwrap()), + 64 => push_unsigned_value(&mut s, scalar_int.try_to_u64().unwrap()), + 128 => push_unsigned_value(&mut s, scalar_int.try_to_u128().unwrap()), + _ => { + bug!("encode_const: unexpected size `{:?}`", scalar_int.size().bits()); + } + }; + } else { + bug!("encode_const: unexpected type `{:?}`", c.ty()); + } + + // Close the "L..E" pair + s.push('E'); + + compress(dict, DictKey::Const(c), &mut s); + + s +} + +/// Encodes a FnSig using the Itanium C++ ABI with vendor extended type qualifiers and types for +/// Rust types that are not used at the FFI boundary. +fn encode_fnsig<'tcx>( + tcx: TyCtxt<'tcx>, + fn_sig: &FnSig<'tcx>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + options: TypeIdOptions, +) -> String { + // Function types are delimited by an "F..E" pair + let mut s = String::from("F"); + + let mut encode_ty_options = EncodeTyOptions::from_bits(options.bits()) + .unwrap_or_else(|| bug!("encode_fnsig: invalid option(s) `{:?}`", options.bits())); + match fn_sig.abi { + Abi::C { .. } => { + encode_ty_options.insert(EncodeTyOptions::GENERALIZE_REPR_C); + } + _ => { + encode_ty_options.remove(EncodeTyOptions::GENERALIZE_REPR_C); + } + } + + // Encode the return type + let transform_ty_options = TransformTyOptions::from_bits(options.bits()) + .unwrap_or_else(|| bug!("encode_fnsig: invalid option(s) `{:?}`", options.bits())); + let ty = transform_ty(tcx, fn_sig.output(), transform_ty_options); + s.push_str(&encode_ty(tcx, ty, dict, encode_ty_options)); + + // Encode the parameter types + let tys = fn_sig.inputs(); + if !tys.is_empty() { + for ty in tys { + let ty = transform_ty(tcx, *ty, transform_ty_options); + s.push_str(&encode_ty(tcx, ty, dict, encode_ty_options)); + } + + if fn_sig.c_variadic { + s.push('z'); + } + } else { + if fn_sig.c_variadic { + s.push('z'); + } else { + // Empty parameter lists, whether declared as () or conventionally as (void), are + // encoded with a void parameter specifier "v". + s.push('v') + } + } + + // Close the "F..E" pair + s.push('E'); + + s +} + +/// Encodes a predicate using the Itanium C++ ABI with vendor extended type qualifiers and types for +/// Rust types that are not used at the FFI boundary. +fn encode_predicate<'tcx>( + tcx: TyCtxt<'tcx>, + predicate: Binder<'tcx, ExistentialPredicate<'tcx>>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + options: EncodeTyOptions, +) -> String { + // u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>, as vendor + // extended type. + let mut s = String::new(); + match predicate.as_ref().skip_binder() { + ty::ExistentialPredicate::Trait(trait_ref) => { + let name = encode_ty_name(tcx, trait_ref.def_id); + let _ = write!(s, "u{}{}", name.len(), &name); + s.push_str(&encode_substs(tcx, trait_ref.substs, dict, options)); + } + ty::ExistentialPredicate::Projection(projection) => { + let name = encode_ty_name(tcx, projection.item_def_id); + let _ = write!(s, "u{}{}", name.len(), &name); + s.push_str(&encode_substs(tcx, projection.substs, dict, options)); + match projection.term { + Term::Ty(ty) => { + s.push_str(&encode_ty(tcx, ty, dict, options)); + } + Term::Const(c) => { + s.push_str(&encode_const(tcx, c, dict, options)); + } + } + } + ty::ExistentialPredicate::AutoTrait(def_id) => { + let name = encode_ty_name(tcx, *def_id); + let _ = write!(s, "u{}{}", name.len(), &name); + } + }; + compress(dict, DictKey::Predicate(*predicate.as_ref().skip_binder()), &mut s); + s +} + +/// Encodes predicates using the Itanium C++ ABI with vendor extended type qualifiers and types for +/// Rust types that are not used at the FFI boundary. +fn encode_predicates<'tcx>( + tcx: TyCtxt<'tcx>, + predicates: &List<Binder<'tcx, ExistentialPredicate<'tcx>>>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + options: EncodeTyOptions, +) -> String { + // <predicate1[..predicateN]>E as part of vendor extended type + let mut s = String::new(); + let predicates: Vec<Binder<'tcx, ExistentialPredicate<'tcx>>> = + predicates.iter().map(|predicate| predicate).collect(); + for predicate in predicates { + s.push_str(&encode_predicate(tcx, predicate, dict, options)); + } + s +} + +/// Encodes a region using the Itanium C++ ABI as a vendor extended type. +fn encode_region<'tcx>( + _tcx: TyCtxt<'tcx>, + region: Region<'tcx>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + _options: EncodeTyOptions, +) -> String { + // u6region[I[<region-disambiguator>][<region-index>]E] as vendor extended type + let mut s = String::new(); + match region.kind() { + RegionKind::ReLateBound(debruijn, r) => { + s.push_str("u6regionI"); + // Debruijn index, which identifies the binder, as region disambiguator + let num = debruijn.index() as u64; + if num > 0 { + s.push_str(&to_disambiguator(num)); + } + // Index within the binder + let _ = write!(s, "{}", r.var.index() as u64); + s.push('E'); + compress(dict, DictKey::Region(region), &mut s); + } + RegionKind::ReErased => { + s.push_str("u6region"); + compress(dict, DictKey::Region(region), &mut s); + } + RegionKind::ReEarlyBound(..) + | RegionKind::ReFree(..) + | RegionKind::ReStatic + | RegionKind::ReVar(..) + | RegionKind::RePlaceholder(..) + | RegionKind::ReEmpty(..) => { + bug!("encode_region: unexpected `{:?}`", region.kind()); + } + } + s +} + +/// Encodes substs using the Itanium C++ ABI with vendor extended type qualifiers and types for Rust +/// types that are not used at the FFI boundary. +fn encode_substs<'tcx>( + tcx: TyCtxt<'tcx>, + substs: SubstsRef<'tcx>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + options: EncodeTyOptions, +) -> String { + // [I<subst1..substN>E] as part of vendor extended type + let mut s = String::new(); + let substs: Vec<GenericArg<'_>> = substs.iter().map(|subst| subst).collect(); + if !substs.is_empty() { + s.push('I'); + for subst in substs { + match subst.unpack() { + GenericArgKind::Lifetime(region) => { + s.push_str(&encode_region(tcx, region, dict, options)); + } + GenericArgKind::Type(ty) => { + s.push_str(&encode_ty(tcx, ty, dict, options)); + } + GenericArgKind::Const(c) => { + s.push_str(&encode_const(tcx, c, dict, options)); + } + } + } + s.push('E'); + } + s +} + +/// Encodes a ty:Ty name, including its crate and path disambiguators and names. +fn encode_ty_name<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> String { + // Encode <name> for use in u<length><name>[I<element-type1..element-typeN>E], where + // <element-type> is <subst>, using v0's <path> without v0's extended form of paths: + // + // N<namespace-tagN>..N<namespace-tag1> + // C<crate-disambiguator><crate-name> + // <path-disambiguator1><path-name1>..<path-disambiguatorN><path-nameN> + // + // With additional tags for DefPathData::Impl and DefPathData::ForeignMod. For instance: + // + // pub type Type1 = impl Send; + // let _: Type1 = <Struct1<i32>>::foo; + // fn foo1(_: Type1) { } + // + // pub type Type2 = impl Send; + // let _: Type2 = <Trait1<i32>>::foo; + // fn foo2(_: Type2) { } + // + // pub type Type3 = impl Send; + // let _: Type3 = <i32 as Trait1<i32>>::foo; + // fn foo3(_: Type3) { } + // + // pub type Type4 = impl Send; + // let _: Type4 = <Struct1<i32> as Trait1<i32>>::foo; + // fn foo3(_: Type4) { } + // + // Are encoded as: + // + // _ZTSFvu29NvNIC1234_5crate8{{impl}}3fooIu3i32EE + // _ZTSFvu27NvNtC1234_5crate6Trait13fooIu3dynIu21NtC1234_5crate6Trait1Iu3i32Eu6regionES_EE + // _ZTSFvu27NvNtC1234_5crate6Trait13fooIu3i32S_EE + // _ZTSFvu27NvNtC1234_5crate6Trait13fooIu22NtC1234_5crate7Struct1Iu3i32ES_EE + // + // The reason for not using v0's extended form of paths is to use a consistent and simpler + // encoding, as the reasoning for using it isn't relevand for type metadata identifiers (i.e., + // keep symbol names close to how methods are represented in error messages). See + // https://rust-lang.github.io/rfcs/2603-rust-symbol-name-mangling-v0.html#methods. + let mut s = String::new(); + + // Start and namespace tags + let mut def_path = tcx.def_path(def_id); + def_path.data.reverse(); + for disambiguated_data in &def_path.data { + s.push('N'); + s.push_str(match disambiguated_data.data { + hir::definitions::DefPathData::Impl => "I", // Not specified in v0's <namespace> + hir::definitions::DefPathData::ForeignMod => "F", // Not specified in v0's <namespace> + hir::definitions::DefPathData::TypeNs(..) => "t", + hir::definitions::DefPathData::ValueNs(..) => "v", + hir::definitions::DefPathData::ClosureExpr => "C", + hir::definitions::DefPathData::Ctor => "c", + hir::definitions::DefPathData::AnonConst => "k", + hir::definitions::DefPathData::ImplTrait => "i", + hir::definitions::DefPathData::CrateRoot + | hir::definitions::DefPathData::Use + | hir::definitions::DefPathData::GlobalAsm + | hir::definitions::DefPathData::MacroNs(..) + | hir::definitions::DefPathData::LifetimeNs(..) => { + bug!("encode_ty_name: unexpected `{:?}`", disambiguated_data.data); + } + }); + } + + // Crate disambiguator and name + s.push('C'); + s.push_str(&to_disambiguator(tcx.stable_crate_id(def_path.krate).to_u64())); + let crate_name = tcx.crate_name(def_path.krate).to_string(); + let _ = write!(s, "{}{}", crate_name.len(), &crate_name); + + // Disambiguators and names + def_path.data.reverse(); + for disambiguated_data in &def_path.data { + let num = disambiguated_data.disambiguator as u64; + if num > 0 { + s.push_str(&to_disambiguator(num)); + } + + let name = disambiguated_data.data.to_string(); + let _ = write!(s, "{}", name.len()); + + // Prepend a '_' if name starts with a digit or '_' + if let Some(first) = name.as_bytes().get(0) { + if first.is_ascii_digit() || *first == b'_' { + s.push('_'); + } + } else { + bug!("encode_ty_name: invalid name `{:?}`", name); + } + + s.push_str(&name); + } + + s +} + +/// Encodes a ty:Ty using the Itanium C++ ABI with vendor extended type qualifiers and types for +/// Rust types that are not used at the FFI boundary. +fn encode_ty<'tcx>( + tcx: TyCtxt<'tcx>, + ty: Ty<'tcx>, + dict: &mut FxHashMap<DictKey<'tcx>, usize>, + options: EncodeTyOptions, +) -> String { + let mut typeid = String::new(); + + match ty.kind() { + // Primitive types + ty::Bool => { + typeid.push('b'); + } + + ty::Int(..) | ty::Uint(..) | ty::Float(..) => { + // u<length><type-name> as vendor extended type + let mut s = String::from(match ty.kind() { + ty::Int(IntTy::I8) => "u2i8", + ty::Int(IntTy::I16) => "u3i16", + ty::Int(IntTy::I32) => "u3i32", + ty::Int(IntTy::I64) => "u3i64", + ty::Int(IntTy::I128) => "u4i128", + ty::Int(IntTy::Isize) => "u5isize", + ty::Uint(UintTy::U8) => "u2u8", + ty::Uint(UintTy::U16) => "u3u16", + ty::Uint(UintTy::U32) => "u3u32", + ty::Uint(UintTy::U64) => "u3u64", + ty::Uint(UintTy::U128) => "u4u128", + ty::Uint(UintTy::Usize) => "u5usize", + ty::Float(FloatTy::F32) => "u3f32", + ty::Float(FloatTy::F64) => "u3f64", + _ => "", + }); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + ty::Char => { + // u4char as vendor extended type + let mut s = String::from("u4char"); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + ty::Str => { + // u3str as vendor extended type + let mut s = String::from("u3str"); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + ty::Never => { + // u5never as vendor extended type + let mut s = String::from("u5never"); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + // Compound types + // () in Rust is equivalent to void return type in C + _ if ty.is_unit() => { + typeid.push('v'); + } + + // Sequence types + ty::Tuple(tys) => { + // u5tupleI<element-type1..element-typeN>E as vendor extended type + let mut s = String::from("u5tupleI"); + for ty in tys.iter() { + s.push_str(&encode_ty(tcx, ty, dict, options)); + } + s.push('E'); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + ty::Array(ty0, len) => { + // A<array-length><element-type> + let mut s = String::from("A"); + let _ = write!(s, "{}", &len.kind().try_to_scalar().unwrap().to_u64().unwrap()); + s.push_str(&encode_ty(tcx, *ty0, dict, options)); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + ty::Slice(ty0) => { + // u5sliceI<element-type>E as vendor extended type + let mut s = String::from("u5sliceI"); + s.push_str(&encode_ty(tcx, *ty0, dict, options)); + s.push('E'); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + // User-defined types + ty::Adt(adt_def, substs) => { + let mut s = String::new(); + let def_id = adt_def.0.did; + if options.contains(EncodeTyOptions::GENERALIZE_REPR_C) && adt_def.repr().c() { + // For for cross-language CFI support, the encoding must be compatible at the FFI + // boundary. For instance: + // + // struct type1 {}; + // void foo(struct type1* bar) {} + // + // Is encoded as: + // + // _ZTSFvP5type1E + // + // So, encode any repr(C) user-defined type for extern function types with the "C" + // calling convention (or extern types [i.e., ty::Foreign]) as <length><name>, where + // <name> is <unscoped-name>. + let name = tcx.item_name(def_id).to_string(); + let _ = write!(s, "{}{}", name.len(), &name); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + } else { + // u<length><name>[I<element-type1..element-typeN>E], where <element-type> is + // <subst>, as vendor extended type. + let name = encode_ty_name(tcx, def_id); + let _ = write!(s, "u{}{}", name.len(), &name); + s.push_str(&encode_substs(tcx, substs, dict, options)); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + } + typeid.push_str(&s); + } + + ty::Foreign(def_id) => { + // <length><name>, where <name> is <unscoped-name> + let mut s = String::new(); + let name = tcx.item_name(*def_id).to_string(); + let _ = write!(s, "{}{}", name.len(), &name); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + // Function types + ty::FnDef(def_id, substs) + | ty::Closure(def_id, substs) + | ty::Generator(def_id, substs, ..) => { + // u<length><name>[I<element-type1..element-typeN>E], where <element-type> is <subst>, + // as vendor extended type. + let mut s = String::new(); + let name = encode_ty_name(tcx, *def_id); + let _ = write!(s, "u{}{}", name.len(), &name); + s.push_str(&encode_substs(tcx, substs, dict, options)); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + // Pointer types + ty::Ref(region, ty0, ..) => { + // [U3mut]u3refI<element-type>E as vendor extended type qualifier and type + let mut s = String::new(); + s.push_str("u3refI"); + s.push_str(&encode_ty(tcx, *ty0, dict, options)); + s.push('E'); + compress(dict, DictKey::Ty(tcx.mk_imm_ref(*region, *ty0), TyQ::None), &mut s); + if ty.is_mutable_ptr() { + s = format!("{}{}", "U3mut", &s); + compress(dict, DictKey::Ty(ty, TyQ::Mut), &mut s); + } + typeid.push_str(&s); + } + + ty::RawPtr(tm) => { + // P[K]<element-type> + let mut s = String::new(); + s.push_str(&encode_ty(tcx, tm.ty, dict, options)); + if !ty.is_mutable_ptr() { + s = format!("{}{}", "K", &s); + compress(dict, DictKey::Ty(tm.ty, TyQ::Const), &mut s); + }; + s = format!("{}{}", "P", &s); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + ty::FnPtr(fn_sig) => { + // PF<return-type><parameter-type1..parameter-typeN>E + let mut s = String::from("P"); + s.push_str(&encode_fnsig(tcx, &fn_sig.skip_binder(), dict, TypeIdOptions::NO_OPTIONS)); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + // Trait types + ty::Dynamic(predicates, region) => { + // u3dynI<element-type1[..element-typeN]>E, where <element-type> is <predicate>, as + // vendor extended type. + let mut s = String::from("u3dynI"); + s.push_str(&encode_predicates(tcx, predicates, dict, options)); + s.push_str(&encode_region(tcx, *region, dict, options)); + s.push('E'); + compress(dict, DictKey::Ty(ty, TyQ::None), &mut s); + typeid.push_str(&s); + } + + // Unexpected types + ty::Bound(..) + | ty::Error(..) + | ty::GeneratorWitness(..) + | ty::Infer(..) + | ty::Opaque(..) + | ty::Param(..) + | ty::Placeholder(..) + | ty::Projection(..) => { + bug!("encode_ty: unexpected `{:?}`", ty.kind()); + } + }; + + typeid +} + +// Transforms a ty:Ty for being encoded and used in the substitution dictionary. It transforms all +// c_void types into unit types unconditionally, and generalizes all pointers if +// TransformTyOptions::GENERALIZE_POINTERS option is set. +fn transform_ty<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, options: TransformTyOptions) -> Ty<'tcx> { + let mut ty = ty; + + match ty.kind() { + ty::Bool + | ty::Int(..) + | ty::Uint(..) + | ty::Float(..) + | ty::Char + | ty::Str + | ty::Never + | ty::Foreign(..) + | ty::Dynamic(..) => {} + + _ if ty.is_unit() => {} + + ty::Tuple(tys) => { + ty = tcx.mk_tup(tys.iter().map(|ty| transform_ty(tcx, ty, options))); + } + + ty::Array(ty0, len) => { + let len = len.kind().try_to_scalar().unwrap().to_u64().unwrap(); + ty = tcx.mk_array(transform_ty(tcx, *ty0, options), len); + } + + ty::Slice(ty0) => { + ty = tcx.mk_slice(transform_ty(tcx, *ty0, options)); + } + + ty::Adt(adt_def, substs) => { + if is_c_void_ty(tcx, ty) { + ty = tcx.mk_unit(); + } else if options.contains(TransformTyOptions::GENERALIZE_REPR_C) && adt_def.repr().c() + { + ty = tcx.mk_adt(*adt_def, ty::List::empty()); + } else if adt_def.repr().transparent() && adt_def.is_struct() { + let variant = adt_def.non_enum_variant(); + let param_env = tcx.param_env(variant.def_id); + let field = variant.fields.iter().find(|field| { + let ty = tcx.type_of(field.did); + let is_zst = + tcx.layout_of(param_env.and(ty)).map_or(false, |layout| layout.is_zst()); + !is_zst + }); + if field.is_none() { + // Transform repr(transparent) types without non-ZST field into () + ty = tcx.mk_unit(); + } else { + let ty0 = tcx.type_of(field.unwrap().did); + // Generalize any repr(transparent) user-defined type that is either a pointer + // or reference, and either references itself or any other type that contains or + // references itself, to avoid a reference cycle. + if ty0.is_any_ptr() && ty0.contains(ty) { + ty = transform_ty( + tcx, + ty0, + options | TransformTyOptions::GENERALIZE_POINTERS, + ); + } else { + ty = transform_ty(tcx, ty0, options); + } + } + } else { + ty = tcx.mk_adt(*adt_def, transform_substs(tcx, substs, options)); + } + } + + ty::FnDef(def_id, substs) => { + ty = tcx.mk_fn_def(*def_id, transform_substs(tcx, substs, options)); + } + + ty::Closure(def_id, substs) => { + ty = tcx.mk_closure(*def_id, transform_substs(tcx, substs, options)); + } + + ty::Generator(def_id, substs, movability) => { + ty = tcx.mk_generator(*def_id, transform_substs(tcx, substs, options), *movability); + } + + ty::Ref(region, ty0, ..) => { + if options.contains(TransformTyOptions::GENERALIZE_POINTERS) { + if ty.is_mutable_ptr() { + ty = tcx.mk_mut_ref(tcx.lifetimes.re_static, tcx.mk_unit()); + } else { + ty = tcx.mk_imm_ref(tcx.lifetimes.re_static, tcx.mk_unit()); + } + } else { + if ty.is_mutable_ptr() { + ty = tcx.mk_mut_ref(*region, transform_ty(tcx, *ty0, options)); + } else { + ty = tcx.mk_imm_ref(*region, transform_ty(tcx, *ty0, options)); + } + } + } + + ty::RawPtr(tm) => { + if options.contains(TransformTyOptions::GENERALIZE_POINTERS) { + if ty.is_mutable_ptr() { + ty = tcx.mk_mut_ptr(tcx.mk_unit()); + } else { + ty = tcx.mk_imm_ptr(tcx.mk_unit()); + } + } else { + if ty.is_mutable_ptr() { + ty = tcx.mk_mut_ptr(transform_ty(tcx, tm.ty, options)); + } else { + ty = tcx.mk_imm_ptr(transform_ty(tcx, tm.ty, options)); + } + } + } + + ty::FnPtr(fn_sig) => { + if options.contains(TransformTyOptions::GENERALIZE_POINTERS) { + ty = tcx.mk_imm_ptr(tcx.mk_unit()); + } else { + let parameters: Vec<Ty<'tcx>> = fn_sig + .skip_binder() + .inputs() + .iter() + .map(|ty| transform_ty(tcx, *ty, options)) + .collect(); + let output = transform_ty(tcx, fn_sig.skip_binder().output(), options); + ty = tcx.mk_fn_ptr(ty::Binder::bind_with_vars( + tcx.mk_fn_sig( + parameters.iter(), + &output, + fn_sig.c_variadic(), + fn_sig.unsafety(), + fn_sig.abi(), + ), + fn_sig.bound_vars(), + )); + } + } + + ty::Bound(..) + | ty::Error(..) + | ty::GeneratorWitness(..) + | ty::Infer(..) + | ty::Opaque(..) + | ty::Param(..) + | ty::Placeholder(..) + | ty::Projection(..) => { + bug!("transform_ty: unexpected `{:?}`", ty.kind()); + } + } + + ty +} + +/// Transforms substs for being encoded and used in the substitution dictionary. +fn transform_substs<'tcx>( + tcx: TyCtxt<'tcx>, + substs: SubstsRef<'tcx>, + options: TransformTyOptions, +) -> SubstsRef<'tcx> { + let substs: Vec<GenericArg<'tcx>> = substs + .iter() + .map(|subst| { + if let GenericArgKind::Type(ty) = subst.unpack() { + if is_c_void_ty(tcx, ty) { + tcx.mk_unit().into() + } else { + transform_ty(tcx, ty, options).into() + } + } else { + subst + } + }) + .collect(); + tcx.mk_substs(substs.iter()) +} + +/// Returns a type metadata identifier for the specified FnAbi using the Itanium C++ ABI with vendor +/// extended type qualifiers and types for Rust types that are not used at the FFI boundary. +pub fn typeid_for_fnabi<'tcx>( + tcx: TyCtxt<'tcx>, + fn_abi: &FnAbi<'tcx, Ty<'tcx>>, + options: TypeIdOptions, +) -> String { + // A name is mangled by prefixing "_Z" to an encoding of its name, and in the case of functions + // its type. + let mut typeid = String::from("_Z"); + + // Clang uses the Itanium C++ ABI's virtual tables and RTTI typeinfo structure name as type + // metadata identifiers for function pointers. The typeinfo name encoding is a two-character + // code (i.e., 'TS') prefixed to the type encoding for the function. + typeid.push_str("TS"); + + // Function types are delimited by an "F..E" pair + typeid.push('F'); + + // A dictionary of substitution candidates used for compression (see + // https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling-compression). + let mut dict: FxHashMap<DictKey<'tcx>, usize> = FxHashMap::default(); + + let mut encode_ty_options = EncodeTyOptions::from_bits(options.bits()) + .unwrap_or_else(|| bug!("typeid_for_fnabi: invalid option(s) `{:?}`", options.bits())); + match fn_abi.conv { + Conv::C => { + encode_ty_options.insert(EncodeTyOptions::GENERALIZE_REPR_C); + } + _ => { + encode_ty_options.remove(EncodeTyOptions::GENERALIZE_REPR_C); + } + } + + // Encode the return type + let transform_ty_options = TransformTyOptions::from_bits(options.bits()) + .unwrap_or_else(|| bug!("typeid_for_fnabi: invalid option(s) `{:?}`", options.bits())); + let ty = transform_ty(tcx, fn_abi.ret.layout.ty, transform_ty_options); + typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options)); + + // Encode the parameter types + if !fn_abi.c_variadic { + if !fn_abi.args.is_empty() { + for arg in fn_abi.args.iter() { + let ty = transform_ty(tcx, arg.layout.ty, transform_ty_options); + typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options)); + } + } else { + // Empty parameter lists, whether declared as () or conventionally as (void), are + // encoded with a void parameter specifier "v". + typeid.push('v'); + } + } else { + for n in 0..fn_abi.fixed_count { + let ty = transform_ty(tcx, fn_abi.args[n].layout.ty, transform_ty_options); + typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options)); + } + + typeid.push('z'); + } + + // Close the "F..E" pair + typeid.push('E'); + + typeid +} + +/// Returns a type metadata identifier for the specified FnSig using the Itanium C++ ABI with vendor +/// extended type qualifiers and types for Rust types that are not used at the FFI boundary. +pub fn typeid_for_fnsig<'tcx>( + tcx: TyCtxt<'tcx>, + fn_sig: &FnSig<'tcx>, + options: TypeIdOptions, +) -> String { + // A name is mangled by prefixing "_Z" to an encoding of its name, and in the case of functions + // its type. + let mut typeid = String::from("_Z"); + + // Clang uses the Itanium C++ ABI's virtual tables and RTTI typeinfo structure name as type + // metadata identifiers for function pointers. The typeinfo name encoding is a two-character + // code (i.e., 'TS') prefixed to the type encoding for the function. + typeid.push_str("TS"); + + // A dictionary of substitution candidates used for compression (see + // https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling-compression). + let mut dict: FxHashMap<DictKey<'tcx>, usize> = FxHashMap::default(); + + // Encode the function signature + typeid.push_str(&encode_fnsig(tcx, fn_sig, &mut dict, options)); + + typeid +} |