1 use rustc_data_structures::base_n;
2 use rustc_data_structures::fx::FxHashMap;
3 use rustc_data_structures::intern::Interned;
4 use rustc_hir as hir;
5 use rustc_hir::def::CtorKind;
6 use rustc_hir::def_id::{CrateNum, DefId};
7 use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData};
8 use rustc_middle::ty::layout::IntegerExt;
9 use rustc_middle::ty::print::{Print, Printer};
10 use rustc_middle::ty::{
11 self, EarlyBinder, FloatTy, Instance, IntTy, Ty, TyCtxt, TypeVisitable, TypeVisitableExt,
12 UintTy,
13 };
14 use rustc_middle::ty::{GenericArg, GenericArgKind};
15 use rustc_span::symbol::kw;
16 use rustc_target::abi::Integer;
17 use rustc_target::spec::abi::Abi;
18
19 use std::fmt::Write;
20 use std::iter;
21 use std::ops::Range;
22
mangle<'tcx>( tcx: TyCtxt<'tcx>, instance: Instance<'tcx>, instantiating_crate: Option<CrateNum>, ) -> String23 pub(super) fn mangle<'tcx>(
24 tcx: TyCtxt<'tcx>,
25 instance: Instance<'tcx>,
26 instantiating_crate: Option<CrateNum>,
27 ) -> String {
28 let def_id = instance.def_id();
29 // FIXME(eddyb) this should ideally not be needed.
30 let substs = tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), instance.substs);
31
32 let prefix = "_R";
33 let mut cx = &mut SymbolMangler {
34 tcx,
35 start_offset: prefix.len(),
36 paths: FxHashMap::default(),
37 types: FxHashMap::default(),
38 consts: FxHashMap::default(),
39 binders: vec![],
40 out: String::from(prefix),
41 };
42
43 // Append `::{shim:...#0}` to shims that can coexist with a non-shim instance.
44 let shim_kind = match instance.def {
45 ty::InstanceDef::ThreadLocalShim(_) => Some("tls"),
46 ty::InstanceDef::VTableShim(_) => Some("vtable"),
47 ty::InstanceDef::ReifyShim(_) => Some("reify"),
48
49 _ => None,
50 };
51
52 cx = if let Some(shim_kind) = shim_kind {
53 cx.path_append_ns(|cx| cx.print_def_path(def_id, substs), 'S', 0, shim_kind).unwrap()
54 } else {
55 cx.print_def_path(def_id, substs).unwrap()
56 };
57 if let Some(instantiating_crate) = instantiating_crate {
58 cx = cx.print_def_path(instantiating_crate.as_def_id(), &[]).unwrap();
59 }
60 std::mem::take(&mut cx.out)
61 }
62
mangle_typeid_for_trait_ref<'tcx>( tcx: TyCtxt<'tcx>, trait_ref: ty::PolyExistentialTraitRef<'tcx>, ) -> String63 pub(super) fn mangle_typeid_for_trait_ref<'tcx>(
64 tcx: TyCtxt<'tcx>,
65 trait_ref: ty::PolyExistentialTraitRef<'tcx>,
66 ) -> String {
67 // FIXME(flip1995): See comment in `mangle_typeid_for_fnabi`.
68 let mut cx = &mut SymbolMangler {
69 tcx,
70 start_offset: 0,
71 paths: FxHashMap::default(),
72 types: FxHashMap::default(),
73 consts: FxHashMap::default(),
74 binders: vec![],
75 out: String::new(),
76 };
77 cx = cx.print_def_path(trait_ref.def_id(), &[]).unwrap();
78 std::mem::take(&mut cx.out)
79 }
80
81 struct BinderLevel {
82 /// The range of distances from the root of what's
83 /// being printed, to the lifetimes in a binder.
84 /// Specifically, a `BrAnon` lifetime has depth
85 /// `lifetime_depths.start + index`, going away from the
86 /// the root and towards its use site, as the var index increases.
87 /// This is used to flatten rustc's pairing of `BrAnon`
88 /// (intra-binder disambiguation) with a `DebruijnIndex`
89 /// (binder addressing), to "true" de Bruijn indices,
90 /// by subtracting the depth of a certain lifetime, from
91 /// the innermost depth at its use site.
92 lifetime_depths: Range<u32>,
93 }
94
95 struct SymbolMangler<'tcx> {
96 tcx: TyCtxt<'tcx>,
97 binders: Vec<BinderLevel>,
98 out: String,
99
100 /// The length of the prefix in `out` (e.g. 2 for `_R`).
101 start_offset: usize,
102 /// The values are start positions in `out`, in bytes.
103 paths: FxHashMap<(DefId, &'tcx [GenericArg<'tcx>]), usize>,
104 types: FxHashMap<Ty<'tcx>, usize>,
105 consts: FxHashMap<ty::Const<'tcx>, usize>,
106 }
107
108 impl<'tcx> SymbolMangler<'tcx> {
push(&mut self, s: &str)109 fn push(&mut self, s: &str) {
110 self.out.push_str(s);
111 }
112
113 /// Push a `_`-terminated base 62 integer, using the format
114 /// specified in the RFC as `<base-62-number>`, that is:
115 /// * `x = 0` is encoded as just the `"_"` terminator
116 /// * `x > 0` is encoded as `x - 1` in base 62, followed by `"_"`,
117 /// e.g. `1` becomes `"0_"`, `62` becomes `"Z_"`, etc.
push_integer_62(&mut self, x: u64)118 fn push_integer_62(&mut self, x: u64) {
119 if let Some(x) = x.checked_sub(1) {
120 base_n::push_str(x as u128, 62, &mut self.out);
121 }
122 self.push("_");
123 }
124
125 /// Push a `tag`-prefixed base 62 integer, when larger than `0`, that is:
126 /// * `x = 0` is encoded as `""` (nothing)
127 /// * `x > 0` is encoded as the `tag` followed by `push_integer_62(x - 1)`
128 /// e.g. `1` becomes `tag + "_"`, `2` becomes `tag + "0_"`, etc.
push_opt_integer_62(&mut self, tag: &str, x: u64)129 fn push_opt_integer_62(&mut self, tag: &str, x: u64) {
130 if let Some(x) = x.checked_sub(1) {
131 self.push(tag);
132 self.push_integer_62(x);
133 }
134 }
135
push_disambiguator(&mut self, dis: u64)136 fn push_disambiguator(&mut self, dis: u64) {
137 self.push_opt_integer_62("s", dis);
138 }
139
push_ident(&mut self, ident: &str)140 fn push_ident(&mut self, ident: &str) {
141 let mut use_punycode = false;
142 for b in ident.bytes() {
143 match b {
144 b'_' | b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' => {}
145 0x80..=0xff => use_punycode = true,
146 _ => bug!("symbol_names: bad byte {} in ident {:?}", b, ident),
147 }
148 }
149
150 let punycode_string;
151 let ident = if use_punycode {
152 self.push("u");
153
154 // FIXME(eddyb) we should probably roll our own punycode implementation.
155 let mut punycode_bytes = match punycode::encode(ident) {
156 Ok(s) => s.into_bytes(),
157 Err(()) => bug!("symbol_names: punycode encoding failed for ident {:?}", ident),
158 };
159
160 // Replace `-` with `_`.
161 if let Some(c) = punycode_bytes.iter_mut().rfind(|&&mut c| c == b'-') {
162 *c = b'_';
163 }
164
165 // FIXME(eddyb) avoid rechecking UTF-8 validity.
166 punycode_string = String::from_utf8(punycode_bytes).unwrap();
167 &punycode_string
168 } else {
169 ident
170 };
171
172 let _ = write!(self.out, "{}", ident.len());
173
174 // Write a separating `_` if necessary (leading digit or `_`).
175 if let Some('_' | '0'..='9') = ident.chars().next() {
176 self.push("_");
177 }
178
179 self.push(ident);
180 }
181
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, !>182 fn path_append_ns<'a>(
183 mut self: &'a mut Self,
184 print_prefix: impl FnOnce(&'a mut Self) -> Result<&'a mut Self, !>,
185 ns: char,
186 disambiguator: u64,
187 name: &str,
188 ) -> Result<&'a mut Self, !> {
189 self.push("N");
190 self.out.push(ns);
191 self = print_prefix(self)?;
192 self.push_disambiguator(disambiguator as u64);
193 self.push_ident(name);
194 Ok(self)
195 }
196
print_backref(&mut self, i: usize) -> Result<&mut Self, !>197 fn print_backref(&mut self, i: usize) -> Result<&mut Self, !> {
198 self.push("B");
199 self.push_integer_62((i - self.start_offset) as u64);
200 Ok(self)
201 }
202
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<TyCtxt<'tcx>>,203 fn in_binder<'a, T>(
204 mut self: &'a mut Self,
205 value: &ty::Binder<'tcx, T>,
206 print_value: impl FnOnce(&'a mut Self, &T) -> Result<&'a mut Self, !>,
207 ) -> Result<&'a mut Self, !>
208 where
209 T: TypeVisitable<TyCtxt<'tcx>>,
210 {
211 let mut lifetime_depths =
212 self.binders.last().map(|b| b.lifetime_depths.end).map_or(0..0, |i| i..i);
213
214 // FIXME(non-lifetime-binders): What to do here?
215 let lifetimes = value
216 .bound_vars()
217 .iter()
218 .filter(|var| matches!(var, ty::BoundVariableKind::Region(..)))
219 .count() as u32;
220
221 self.push_opt_integer_62("G", lifetimes as u64);
222 lifetime_depths.end += lifetimes;
223
224 self.binders.push(BinderLevel { lifetime_depths });
225 self = print_value(self, value.as_ref().skip_binder())?;
226 self.binders.pop();
227
228 Ok(self)
229 }
230 }
231
232 impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
233 type Error = !;
234
235 type Path = Self;
236 type Region = Self;
237 type Type = Self;
238 type DynExistential = Self;
239 type Const = Self;
240
tcx(&self) -> TyCtxt<'tcx>241 fn tcx(&self) -> TyCtxt<'tcx> {
242 self.tcx
243 }
244
print_def_path( mut self, def_id: DefId, substs: &'tcx [GenericArg<'tcx>], ) -> Result<Self::Path, Self::Error>245 fn print_def_path(
246 mut self,
247 def_id: DefId,
248 substs: &'tcx [GenericArg<'tcx>],
249 ) -> Result<Self::Path, Self::Error> {
250 if let Some(&i) = self.paths.get(&(def_id, substs)) {
251 return self.print_backref(i);
252 }
253 let start = self.out.len();
254
255 self = self.default_print_def_path(def_id, substs)?;
256
257 // Only cache paths that do not refer to an enclosing
258 // binder (which would change depending on context).
259 if !substs.iter().any(|k| k.has_escaping_bound_vars()) {
260 self.paths.insert((def_id, substs), start);
261 }
262 Ok(self)
263 }
264
print_impl_path( mut 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>265 fn print_impl_path(
266 mut self,
267 impl_def_id: DefId,
268 substs: &'tcx [GenericArg<'tcx>],
269 mut self_ty: Ty<'tcx>,
270 mut impl_trait_ref: Option<ty::TraitRef<'tcx>>,
271 ) -> Result<Self::Path, Self::Error> {
272 let key = self.tcx.def_key(impl_def_id);
273 let parent_def_id = DefId { index: key.parent.unwrap(), ..impl_def_id };
274
275 let mut param_env = self.tcx.param_env_reveal_all_normalized(impl_def_id);
276 if !substs.is_empty() {
277 param_env = EarlyBinder::bind(param_env).subst(self.tcx, substs);
278 }
279
280 match &mut impl_trait_ref {
281 Some(impl_trait_ref) => {
282 assert_eq!(impl_trait_ref.self_ty(), self_ty);
283 *impl_trait_ref = self.tcx.normalize_erasing_regions(param_env, *impl_trait_ref);
284 self_ty = impl_trait_ref.self_ty();
285 }
286 None => {
287 self_ty = self.tcx.normalize_erasing_regions(param_env, self_ty);
288 }
289 }
290
291 self.push(match impl_trait_ref {
292 Some(_) => "X",
293 None => "M",
294 });
295
296 // Encode impl generic params if the substitutions contain parameters (implying
297 // polymorphization is enabled) and this isn't an inherent impl.
298 if impl_trait_ref.is_some() && substs.iter().any(|a| a.has_non_region_param()) {
299 self = self.path_generic_args(
300 |this| {
301 this.path_append_ns(
302 |cx| cx.print_def_path(parent_def_id, &[]),
303 'I',
304 key.disambiguated_data.disambiguator as u64,
305 "",
306 )
307 },
308 substs,
309 )?;
310 } else {
311 self.push_disambiguator(key.disambiguated_data.disambiguator as u64);
312 self = self.print_def_path(parent_def_id, &[])?;
313 }
314
315 self = self_ty.print(self)?;
316
317 if let Some(trait_ref) = impl_trait_ref {
318 self = self.print_def_path(trait_ref.def_id, trait_ref.substs)?;
319 }
320
321 Ok(self)
322 }
323
print_region(self, region: ty::Region<'_>) -> Result<Self::Region, Self::Error>324 fn print_region(self, region: ty::Region<'_>) -> Result<Self::Region, Self::Error> {
325 let i = match *region {
326 // Erased lifetimes use the index 0, for a
327 // shorter mangling of `L_`.
328 ty::ReErased => 0,
329
330 // Late-bound lifetimes use indices starting at 1,
331 // see `BinderLevel` for more details.
332 ty::ReLateBound(debruijn, ty::BoundRegion { var, kind: ty::BrAnon(_) }) => {
333 let binder = &self.binders[self.binders.len() - 1 - debruijn.index()];
334 let depth = binder.lifetime_depths.start + var.as_u32();
335
336 1 + (self.binders.last().unwrap().lifetime_depths.end - 1 - depth)
337 }
338
339 _ => bug!("symbol_names: non-erased region `{:?}`", region),
340 };
341 self.push("L");
342 self.push_integer_62(i as u64);
343 Ok(self)
344 }
345
print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error>346 fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> {
347 // Basic types, never cached (single-character).
348 let basic_type = match ty.kind() {
349 ty::Bool => "b",
350 ty::Char => "c",
351 ty::Str => "e",
352 ty::Tuple(_) if ty.is_unit() => "u",
353 ty::Int(IntTy::I8) => "a",
354 ty::Int(IntTy::I16) => "s",
355 ty::Int(IntTy::I32) => "l",
356 ty::Int(IntTy::I64) => "x",
357 ty::Int(IntTy::I128) => "n",
358 ty::Int(IntTy::Isize) => "i",
359 ty::Uint(UintTy::U8) => "h",
360 ty::Uint(UintTy::U16) => "t",
361 ty::Uint(UintTy::U32) => "m",
362 ty::Uint(UintTy::U64) => "y",
363 ty::Uint(UintTy::U128) => "o",
364 ty::Uint(UintTy::Usize) => "j",
365 ty::Float(FloatTy::F32) => "f",
366 ty::Float(FloatTy::F64) => "d",
367 ty::Never => "z",
368
369 // Placeholders (should be demangled as `_`).
370 ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => "p",
371
372 _ => "",
373 };
374 if !basic_type.is_empty() {
375 self.push(basic_type);
376 return Ok(self);
377 }
378
379 if let Some(&i) = self.types.get(&ty) {
380 return self.print_backref(i);
381 }
382 let start = self.out.len();
383
384 match *ty.kind() {
385 // Basic types, handled above.
386 ty::Bool | ty::Char | ty::Str | ty::Int(_) | ty::Uint(_) | ty::Float(_) | ty::Never => {
387 unreachable!()
388 }
389 ty::Tuple(_) if ty.is_unit() => unreachable!(),
390
391 // Placeholders, also handled as part of basic types.
392 ty::Param(_) | ty::Bound(..) | ty::Placeholder(_) | ty::Infer(_) | ty::Error(_) => {
393 unreachable!()
394 }
395
396 ty::Ref(r, ty, mutbl) => {
397 self.push(match mutbl {
398 hir::Mutability::Not => "R",
399 hir::Mutability::Mut => "Q",
400 });
401 if !r.is_erased() {
402 self = r.print(self)?;
403 }
404 self = ty.print(self)?;
405 }
406
407 ty::RawPtr(mt) => {
408 self.push(match mt.mutbl {
409 hir::Mutability::Not => "P",
410 hir::Mutability::Mut => "O",
411 });
412 self = mt.ty.print(self)?;
413 }
414
415 ty::Array(ty, len) => {
416 self.push("A");
417 self = ty.print(self)?;
418 self = self.print_const(len)?;
419 }
420 ty::Slice(ty) => {
421 self.push("S");
422 self = ty.print(self)?;
423 }
424
425 ty::Tuple(tys) => {
426 self.push("T");
427 for ty in tys.iter() {
428 self = ty.print(self)?;
429 }
430 self.push("E");
431 }
432
433 // Mangle all nominal types as paths.
434 ty::Adt(ty::AdtDef(Interned(&ty::AdtDefData { did: def_id, .. }, _)), substs)
435 | ty::FnDef(def_id, substs)
436 | ty::Alias(ty::Projection | ty::Opaque, ty::AliasTy { def_id, substs, .. })
437 | ty::Closure(def_id, substs)
438 | ty::Generator(def_id, substs, _) => {
439 self = self.print_def_path(def_id, substs)?;
440 }
441 ty::Foreign(def_id) => {
442 self = self.print_def_path(def_id, &[])?;
443 }
444
445 ty::FnPtr(sig) => {
446 self.push("F");
447 self = self.in_binder(&sig, |mut cx, sig| {
448 if sig.unsafety == hir::Unsafety::Unsafe {
449 cx.push("U");
450 }
451 match sig.abi {
452 Abi::Rust => {}
453 Abi::C { unwind: false } => cx.push("KC"),
454 abi => {
455 cx.push("K");
456 let name = abi.name();
457 if name.contains('-') {
458 cx.push_ident(&name.replace('-', "_"));
459 } else {
460 cx.push_ident(name);
461 }
462 }
463 }
464 for &ty in sig.inputs() {
465 cx = ty.print(cx)?;
466 }
467 if sig.c_variadic {
468 cx.push("v");
469 }
470 cx.push("E");
471 sig.output().print(cx)
472 })?;
473 }
474
475 ty::Dynamic(predicates, r, kind) => {
476 self.push(match kind {
477 ty::Dyn => "D",
478 // FIXME(dyn-star): need to update v0 mangling docs
479 ty::DynStar => "D*",
480 });
481 self = self.print_dyn_existential(predicates)?;
482 self = r.print(self)?;
483 }
484
485 ty::Alias(ty::Inherent, _) => bug!("symbol_names: unexpected inherent projection"),
486 ty::Alias(ty::Weak, _) => bug!("symbol_names: unexpected weak projection"),
487 ty::GeneratorWitness(_) => bug!("symbol_names: unexpected `GeneratorWitness`"),
488 ty::GeneratorWitnessMIR(..) => bug!("symbol_names: unexpected `GeneratorWitnessMIR`"),
489 }
490
491 // Only cache types that do not refer to an enclosing
492 // binder (which would change depending on context).
493 if !ty.has_escaping_bound_vars() {
494 self.types.insert(ty, start);
495 }
496 Ok(self)
497 }
498
print_dyn_existential( mut self, predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>, ) -> Result<Self::DynExistential, Self::Error>499 fn print_dyn_existential(
500 mut self,
501 predicates: &'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>,
502 ) -> Result<Self::DynExistential, Self::Error> {
503 // Okay, so this is a bit tricky. Imagine we have a trait object like
504 // `dyn for<'a> Foo<'a, Bar = &'a ()>`. When we mangle this, the
505 // output looks really close to the syntax, where the `Bar = &'a ()` bit
506 // is under the same binders (`['a]`) as the `Foo<'a>` bit. However, we
507 // actually desugar these into two separate `ExistentialPredicate`s. We
508 // can't enter/exit the "binder scope" twice though, because then we
509 // would mangle the binders twice. (Also, side note, we merging these
510 // two is kind of difficult, because of potential HRTBs in the Projection
511 // predicate.)
512 //
513 // Also worth mentioning: imagine that we instead had
514 // `dyn for<'a> Foo<'a, Bar = &'a ()> + Send`. In this case, `Send` is
515 // under the same binders as `Foo`. Currently, this doesn't matter,
516 // because only *auto traits* are allowed other than the principal trait
517 // and all auto traits don't have any generics. Two things could
518 // make this not an "okay" mangling:
519 // 1) Instead of mangling only *used*
520 // bound vars, we want to mangle *all* bound vars (`for<'b> Send` is a
521 // valid trait predicate);
522 // 2) We allow multiple "principal" traits in the future, or at least
523 // allow in any form another trait predicate that can take generics.
524 //
525 // Here we assume that predicates have the following structure:
526 // [<Trait> [{<Projection>}]] [{<Auto>}]
527 // Since any predicates after the first one shouldn't change the binders,
528 // just put them all in the binders of the first.
529 self = self.in_binder(&predicates[0], |mut cx, _| {
530 for predicate in predicates.iter() {
531 // It would be nice to be able to validate bound vars here, but
532 // projections can actually include bound vars from super traits
533 // because of HRTBs (only in the `Self` type). Also, auto traits
534 // could have different bound vars *anyways*.
535 match predicate.as_ref().skip_binder() {
536 ty::ExistentialPredicate::Trait(trait_ref) => {
537 // Use a type that can't appear in defaults of type parameters.
538 let dummy_self = Ty::new_fresh(cx.tcx, 0);
539 let trait_ref = trait_ref.with_self_ty(cx.tcx, dummy_self);
540 cx = cx.print_def_path(trait_ref.def_id, trait_ref.substs)?;
541 }
542 ty::ExistentialPredicate::Projection(projection) => {
543 let name = cx.tcx.associated_item(projection.def_id).name;
544 cx.push("p");
545 cx.push_ident(name.as_str());
546 cx = match projection.term.unpack() {
547 ty::TermKind::Ty(ty) => ty.print(cx),
548 ty::TermKind::Const(c) => c.print(cx),
549 }?;
550 }
551 ty::ExistentialPredicate::AutoTrait(def_id) => {
552 cx = cx.print_def_path(*def_id, &[])?;
553 }
554 }
555 }
556 Ok(cx)
557 })?;
558
559 self.push("E");
560 Ok(self)
561 }
562
print_const(mut self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error>563 fn print_const(mut self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> {
564 // We only mangle a typed value if the const can be evaluated.
565 let ct = ct.eval(self.tcx, ty::ParamEnv::reveal_all());
566 match ct.kind() {
567 ty::ConstKind::Value(_) => {}
568
569 // Placeholders (should be demangled as `_`).
570 // NOTE(eddyb) despite `Unevaluated` having a `DefId` (and therefore
571 // a path), even for it we still need to encode a placeholder, as
572 // the path could refer back to e.g. an `impl` using the constant.
573 ty::ConstKind::Unevaluated(_)
574 | ty::ConstKind::Expr(_)
575 | ty::ConstKind::Param(_)
576 | ty::ConstKind::Infer(_)
577 | ty::ConstKind::Bound(..)
578 | ty::ConstKind::Placeholder(_)
579 | ty::ConstKind::Error(_) => {
580 // Never cached (single-character).
581 self.push("p");
582 return Ok(self);
583 }
584 }
585
586 if let Some(&i) = self.consts.get(&ct) {
587 return self.print_backref(i);
588 }
589
590 let start = self.out.len();
591 let ty = ct.ty();
592
593 match ty.kind() {
594 ty::Uint(_) | ty::Int(_) | ty::Bool | ty::Char => {
595 self = ty.print(self)?;
596
597 let mut bits = ct.eval_bits(self.tcx, ty::ParamEnv::reveal_all(), ty);
598
599 // Negative integer values are mangled using `n` as a "sign prefix".
600 if let ty::Int(ity) = ty.kind() {
601 let val =
602 Integer::from_int_ty(&self.tcx, *ity).size().sign_extend(bits) as i128;
603 if val < 0 {
604 self.push("n");
605 }
606 bits = val.unsigned_abs();
607 }
608
609 let _ = write!(self.out, "{bits:x}_");
610 }
611
612 // FIXME(valtrees): Remove the special case for `str`
613 // here and fully support unsized constants.
614 ty::Ref(_, inner_ty, mutbl) => {
615 self.push(match mutbl {
616 hir::Mutability::Not => "R",
617 hir::Mutability::Mut => "Q",
618 });
619
620 match inner_ty.kind() {
621 ty::Str if mutbl.is_not() => {
622 match ct.kind() {
623 ty::ConstKind::Value(valtree) => {
624 let slice =
625 valtree.try_to_raw_bytes(self.tcx(), ty).unwrap_or_else(|| {
626 bug!(
627 "expected to get raw bytes from valtree {:?} for type {:}",
628 valtree, ty
629 )
630 });
631 let s = std::str::from_utf8(slice).expect("non utf8 str from miri");
632
633 self.push("e");
634
635 // FIXME(eddyb) use a specialized hex-encoding loop.
636 for byte in s.bytes() {
637 let _ = write!(self.out, "{byte:02x}");
638 }
639
640 self.push("_");
641 }
642
643 _ => {
644 bug!("symbol_names: unsupported `&str` constant: {:?}", ct);
645 }
646 }
647 }
648 _ => {
649 let pointee_ty = ct
650 .ty()
651 .builtin_deref(true)
652 .expect("tried to dereference on non-ptr type")
653 .ty;
654 // FIXME(const_generics): add an assert that we only do this for valtrees.
655 let dereferenced_const = self.tcx.mk_ct_from_kind(ct.kind(), pointee_ty);
656 self = dereferenced_const.print(self)?;
657 }
658 }
659 }
660
661 ty::Array(..) | ty::Tuple(..) | ty::Adt(..) | ty::Slice(_) => {
662 let contents = self.tcx.destructure_const(ct);
663 let fields = contents.fields.iter().copied();
664
665 let print_field_list = |mut this: Self| {
666 for field in fields.clone() {
667 this = field.print(this)?;
668 }
669 this.push("E");
670 Ok(this)
671 };
672
673 match *ct.ty().kind() {
674 ty::Array(..) | ty::Slice(_) => {
675 self.push("A");
676 self = print_field_list(self)?;
677 }
678 ty::Tuple(..) => {
679 self.push("T");
680 self = print_field_list(self)?;
681 }
682 ty::Adt(def, substs) => {
683 let variant_idx =
684 contents.variant.expect("destructed const of adt without variant idx");
685 let variant_def = &def.variant(variant_idx);
686
687 self.push("V");
688 self = self.print_def_path(variant_def.def_id, substs)?;
689
690 match variant_def.ctor_kind() {
691 Some(CtorKind::Const) => {
692 self.push("U");
693 }
694 Some(CtorKind::Fn) => {
695 self.push("T");
696 self = print_field_list(self)?;
697 }
698 None => {
699 self.push("S");
700 for (field_def, field) in iter::zip(&variant_def.fields, fields) {
701 // HACK(eddyb) this mimics `path_append`,
702 // instead of simply using `field_def.ident`,
703 // just to be able to handle disambiguators.
704 let disambiguated_field =
705 self.tcx.def_key(field_def.did).disambiguated_data;
706 let field_name = disambiguated_field.data.get_opt_name();
707 self.push_disambiguator(
708 disambiguated_field.disambiguator as u64,
709 );
710 self.push_ident(field_name.unwrap_or(kw::Empty).as_str());
711
712 self = field.print(self)?;
713 }
714 self.push("E");
715 }
716 }
717 }
718 _ => unreachable!(),
719 }
720 }
721 _ => {
722 bug!("symbol_names: unsupported constant of type `{}` ({:?})", ct.ty(), ct);
723 }
724 }
725
726 // Only cache consts that do not refer to an enclosing
727 // binder (which would change depending on context).
728 if !ct.has_escaping_bound_vars() {
729 self.consts.insert(ct, start);
730 }
731 Ok(self)
732 }
733
path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error>734 fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> {
735 self.push("C");
736 let stable_crate_id = self.tcx.def_path_hash(cnum.as_def_id()).stable_crate_id();
737 self.push_disambiguator(stable_crate_id.as_u64());
738 let name = self.tcx.crate_name(cnum);
739 self.push_ident(name.as_str());
740 Ok(self)
741 }
742
path_qualified( mut self, self_ty: Ty<'tcx>, trait_ref: Option<ty::TraitRef<'tcx>>, ) -> Result<Self::Path, Self::Error>743 fn path_qualified(
744 mut self,
745 self_ty: Ty<'tcx>,
746 trait_ref: Option<ty::TraitRef<'tcx>>,
747 ) -> Result<Self::Path, Self::Error> {
748 assert!(trait_ref.is_some());
749 let trait_ref = trait_ref.unwrap();
750
751 self.push("Y");
752 self = self_ty.print(self)?;
753 self.print_def_path(trait_ref.def_id, trait_ref.substs)
754 }
755
path_append_impl( self, _: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, _: &DisambiguatedDefPathData, _: Ty<'tcx>, _: Option<ty::TraitRef<'tcx>>, ) -> Result<Self::Path, Self::Error>756 fn path_append_impl(
757 self,
758 _: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
759 _: &DisambiguatedDefPathData,
760 _: Ty<'tcx>,
761 _: Option<ty::TraitRef<'tcx>>,
762 ) -> Result<Self::Path, Self::Error> {
763 // Inlined into `print_impl_path`
764 unreachable!()
765 }
766
path_append( self, print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, disambiguated_data: &DisambiguatedDefPathData, ) -> Result<Self::Path, Self::Error>767 fn path_append(
768 self,
769 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
770 disambiguated_data: &DisambiguatedDefPathData,
771 ) -> Result<Self::Path, Self::Error> {
772 let ns = match disambiguated_data.data {
773 // Extern block segments can be skipped, names from extern blocks
774 // are effectively living in their parent modules.
775 DefPathData::ForeignMod => return print_prefix(self),
776
777 // Uppercase categories are more stable than lowercase ones.
778 DefPathData::TypeNs(_) => 't',
779 DefPathData::ValueNs(_) => 'v',
780 DefPathData::ClosureExpr => 'C',
781 DefPathData::Ctor => 'c',
782 DefPathData::AnonConst => 'k',
783 DefPathData::ImplTrait => 'i',
784
785 // These should never show up as `path_append` arguments.
786 DefPathData::CrateRoot
787 | DefPathData::Use
788 | DefPathData::GlobalAsm
789 | DefPathData::Impl
790 | DefPathData::ImplTraitAssocTy
791 | DefPathData::MacroNs(_)
792 | DefPathData::LifetimeNs(_) => {
793 bug!("symbol_names: unexpected DefPathData: {:?}", disambiguated_data.data)
794 }
795 };
796
797 let name = disambiguated_data.data.get_opt_name();
798
799 self.path_append_ns(
800 print_prefix,
801 ns,
802 disambiguated_data.disambiguator as u64,
803 name.unwrap_or(kw::Empty).as_str(),
804 )
805 }
806
path_generic_args( mut self, print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, args: &[GenericArg<'tcx>], ) -> Result<Self::Path, Self::Error>807 fn path_generic_args(
808 mut self,
809 print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>,
810 args: &[GenericArg<'tcx>],
811 ) -> Result<Self::Path, Self::Error> {
812 // Don't print any regions if they're all erased.
813 let print_regions = args.iter().any(|arg| match arg.unpack() {
814 GenericArgKind::Lifetime(r) => !r.is_erased(),
815 _ => false,
816 });
817 let args = args.iter().cloned().filter(|arg| match arg.unpack() {
818 GenericArgKind::Lifetime(_) => print_regions,
819 _ => true,
820 });
821
822 if args.clone().next().is_none() {
823 return print_prefix(self);
824 }
825
826 self.push("I");
827 self = print_prefix(self)?;
828 for arg in args {
829 match arg.unpack() {
830 GenericArgKind::Lifetime(lt) => {
831 self = lt.print(self)?;
832 }
833 GenericArgKind::Type(ty) => {
834 self = ty.print(self)?;
835 }
836 GenericArgKind::Const(c) => {
837 self.push("K");
838 self = c.print(self)?;
839 }
840 }
841 }
842 self.push("E");
843
844 Ok(self)
845 }
846 }
847