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Commit | Line | Data |
---|---|---|
dc9dc135 | 1 | use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; |
dfeec247 | 2 | use rustc_hir::def_id::CrateNum; |
ba9703b0 | 3 | use rustc_hir::definitions::{DefPathData, DisambiguatedDefPathData}; |
ba9703b0 XL |
4 | use rustc_middle::ty::print::{PrettyPrinter, Print, Printer}; |
5 | use rustc_middle::ty::subst::{GenericArg, GenericArgKind}; | |
064997fb | 6 | use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeVisitable}; |
ba9703b0 | 7 | use rustc_middle::util::common::record_time; |
dc9dc135 | 8 | |
3dfed10e | 9 | use tracing::debug; |
dc9dc135 XL |
10 | |
11 | use std::fmt::{self, Write}; | |
12 | use std::mem::{self, discriminant}; | |
13 | ||
a2a8927a | 14 | pub(super) fn mangle<'tcx>( |
dc9dc135 XL |
15 | tcx: TyCtxt<'tcx>, |
16 | instance: Instance<'tcx>, | |
17 | instantiating_crate: Option<CrateNum>, | |
18 | ) -> String { | |
19 | let def_id = instance.def_id(); | |
20 | ||
21 | // We want to compute the "type" of this item. Unfortunately, some | |
22 | // kinds of items (e.g., closures) don't have an entry in the | |
23 | // item-type array. So walk back up the find the closest parent | |
24 | // that DOES have an entry. | |
25 | let mut ty_def_id = def_id; | |
26 | let instance_ty; | |
27 | loop { | |
28 | let key = tcx.def_key(ty_def_id); | |
29 | match key.disambiguated_data.data { | |
30 | DefPathData::TypeNs(_) | DefPathData::ValueNs(_) => { | |
31 | instance_ty = tcx.type_of(ty_def_id); | |
923072b8 | 32 | debug!(?instance_ty); |
dc9dc135 XL |
33 | break; |
34 | } | |
35 | _ => { | |
36 | // if we're making a symbol for something, there ought | |
37 | // to be a value or type-def or something in there | |
38 | // *somewhere* | |
39 | ty_def_id.index = key.parent.unwrap_or_else(|| { | |
40 | bug!( | |
41 | "finding type for {:?}, encountered def-id {:?} with no \ | |
42 | parent", | |
43 | def_id, | |
44 | ty_def_id | |
45 | ); | |
46 | }); | |
47 | } | |
48 | } | |
49 | } | |
50 | ||
51 | // Erase regions because they may not be deterministic when hashed | |
52 | // and should not matter anyhow. | |
fc512014 | 53 | let instance_ty = tcx.erase_regions(instance_ty); |
dc9dc135 XL |
54 | |
55 | let hash = get_symbol_hash(tcx, instance, instance_ty, instantiating_crate); | |
56 | ||
94222f64 XL |
57 | let mut printer = SymbolPrinter { tcx, path: SymbolPath::new(), keep_within_component: false }; |
58 | printer | |
5869c6ff XL |
59 | .print_def_path( |
60 | def_id, | |
61 | if let ty::InstanceDef::DropGlue(_, _) = instance.def { | |
62 | // Add the name of the dropped type to the symbol name | |
63 | &*instance.substs | |
64 | } else { | |
65 | &[] | |
66 | }, | |
67 | ) | |
dfeec247 | 68 | .unwrap(); |
dc9dc135 | 69 | |
064997fb | 70 | if let ty::InstanceDef::VTableShim(..) = instance.def { |
dc9dc135 XL |
71 | let _ = printer.write_str("{{vtable-shim}}"); |
72 | } | |
73 | ||
ba9703b0 XL |
74 | if let ty::InstanceDef::ReifyShim(..) = instance.def { |
75 | let _ = printer.write_str("{{reify-shim}}"); | |
76 | } | |
77 | ||
dc9dc135 XL |
78 | printer.path.finish(hash) |
79 | } | |
80 | ||
81 | fn get_symbol_hash<'tcx>( | |
82 | tcx: TyCtxt<'tcx>, | |
83 | ||
84 | // instance this name will be for | |
85 | instance: Instance<'tcx>, | |
86 | ||
87 | // type of the item, without any generic | |
88 | // parameters substituted; this is | |
89 | // included in the hash as a kind of | |
90 | // safeguard. | |
91 | item_type: Ty<'tcx>, | |
92 | ||
93 | instantiating_crate: Option<CrateNum>, | |
94 | ) -> u64 { | |
95 | let def_id = instance.def_id(); | |
96 | let substs = instance.substs; | |
dfeec247 | 97 | debug!("get_symbol_hash(def_id={:?}, parameters={:?})", def_id, substs); |
dc9dc135 | 98 | |
064997fb FG |
99 | tcx.with_stable_hashing_context(|mut hcx| { |
100 | let mut hasher = StableHasher::new(); | |
101 | ||
102 | record_time(&tcx.sess.perf_stats.symbol_hash_time, || { | |
103 | // the main symbol name is not necessarily unique; hash in the | |
104 | // compiler's internal def-path, guaranteeing each symbol has a | |
105 | // truly unique path | |
106 | tcx.def_path_hash(def_id).hash_stable(&mut hcx, &mut hasher); | |
107 | ||
108 | // Include the main item-type. Note that, in this case, the | |
109 | // assertions about `needs_subst` may not hold, but this item-type | |
110 | // ought to be the same for every reference anyway. | |
111 | assert!(!item_type.has_erasable_regions()); | |
112 | hcx.while_hashing_spans(false, |hcx| { | |
113 | item_type.hash_stable(hcx, &mut hasher); | |
114 | ||
115 | // If this is a function, we hash the signature as well. | |
116 | // This is not *strictly* needed, but it may help in some | |
117 | // situations, see the `run-make/a-b-a-linker-guard` test. | |
118 | if let ty::FnDef(..) = item_type.kind() { | |
119 | item_type.fn_sig(tcx).hash_stable(hcx, &mut hasher); | |
120 | } | |
121 | ||
122 | // also include any type parameters (for generic items) | |
123 | substs.hash_stable(hcx, &mut hasher); | |
124 | ||
125 | if let Some(instantiating_crate) = instantiating_crate { | |
126 | tcx.def_path_hash(instantiating_crate.as_def_id()) | |
127 | .stable_crate_id() | |
128 | .hash_stable(hcx, &mut hasher); | |
129 | } | |
130 | ||
131 | // We want to avoid accidental collision between different types of instances. | |
132 | // Especially, `VTableShim`s and `ReifyShim`s may overlap with their original | |
133 | // instances without this. | |
134 | discriminant(&instance.def).hash_stable(hcx, &mut hasher); | |
135 | }); | |
dc9dc135 | 136 | }); |
dc9dc135 | 137 | |
064997fb FG |
138 | // 64 bits should be enough to avoid collisions. |
139 | hasher.finish::<u64>() | |
140 | }) | |
dc9dc135 XL |
141 | } |
142 | ||
143 | // Follow C++ namespace-mangling style, see | |
3dfed10e | 144 | // https://en.wikipedia.org/wiki/Name_mangling for more info. |
dc9dc135 XL |
145 | // |
146 | // It turns out that on macOS you can actually have arbitrary symbols in | |
147 | // function names (at least when given to LLVM), but this is not possible | |
148 | // when using unix's linker. Perhaps one day when we just use a linker from LLVM | |
149 | // we won't need to do this name mangling. The problem with name mangling is | |
150 | // that it seriously limits the available characters. For example we can't | |
151 | // have things like &T in symbol names when one would theoretically | |
152 | // want them for things like impls of traits on that type. | |
153 | // | |
154 | // To be able to work on all platforms and get *some* reasonable output, we | |
155 | // use C++ name-mangling. | |
156 | #[derive(Debug)] | |
157 | struct SymbolPath { | |
158 | result: String, | |
159 | temp_buf: String, | |
160 | } | |
161 | ||
162 | impl SymbolPath { | |
163 | fn new() -> Self { | |
dfeec247 XL |
164 | let mut result = |
165 | SymbolPath { result: String::with_capacity(64), temp_buf: String::with_capacity(16) }; | |
dc9dc135 XL |
166 | result.result.push_str("_ZN"); // _Z == Begin name-sequence, N == nested |
167 | result | |
168 | } | |
169 | ||
170 | fn finalize_pending_component(&mut self) { | |
171 | if !self.temp_buf.is_empty() { | |
172 | let _ = write!(self.result, "{}{}", self.temp_buf.len(), self.temp_buf); | |
173 | self.temp_buf.clear(); | |
174 | } | |
175 | } | |
176 | ||
177 | fn finish(mut self, hash: u64) -> String { | |
178 | self.finalize_pending_component(); | |
179 | // E = end name-sequence | |
180 | let _ = write!(self.result, "17h{:016x}E", hash); | |
181 | self.result | |
182 | } | |
183 | } | |
184 | ||
185 | struct SymbolPrinter<'tcx> { | |
186 | tcx: TyCtxt<'tcx>, | |
187 | path: SymbolPath, | |
188 | ||
189 | // When `true`, `finalize_pending_component` isn't used. | |
190 | // This is needed when recursing into `path_qualified`, | |
191 | // or `path_generic_args`, as any nested paths are | |
192 | // logically within one component. | |
193 | keep_within_component: bool, | |
194 | } | |
195 | ||
196 | // HACK(eddyb) this relies on using the `fmt` interface to get | |
197 | // `PrettyPrinter` aka pretty printing of e.g. types in paths, | |
198 | // symbol names should have their own printing machinery. | |
199 | ||
a2a8927a | 200 | impl<'tcx> Printer<'tcx> for &mut SymbolPrinter<'tcx> { |
dc9dc135 XL |
201 | type Error = fmt::Error; |
202 | ||
203 | type Path = Self; | |
204 | type Region = Self; | |
205 | type Type = Self; | |
206 | type DynExistential = Self; | |
207 | type Const = Self; | |
208 | ||
209 | fn tcx(&self) -> TyCtxt<'tcx> { | |
210 | self.tcx | |
211 | } | |
212 | ||
dfeec247 | 213 | fn print_region(self, _region: ty::Region<'_>) -> Result<Self::Region, Self::Error> { |
dc9dc135 XL |
214 | Ok(self) |
215 | } | |
216 | ||
5e7ed085 | 217 | fn print_type(mut self, ty: Ty<'tcx>) -> Result<Self::Type, Self::Error> { |
1b1a35ee | 218 | match *ty.kind() { |
dc9dc135 | 219 | // Print all nominal types as paths (unlike `pretty_print_type`). |
dfeec247 XL |
220 | ty::FnDef(def_id, substs) |
221 | | ty::Opaque(def_id, substs) | |
222 | | ty::Projection(ty::ProjectionTy { item_def_id: def_id, substs }) | |
dfeec247 XL |
223 | | ty::Closure(def_id, substs) |
224 | | ty::Generator(def_id, substs, _) => self.print_def_path(def_id, substs), | |
5e7ed085 FG |
225 | |
226 | // The `pretty_print_type` formatting of array size depends on | |
227 | // -Zverbose flag, so we cannot reuse it here. | |
228 | ty::Array(ty, size) => { | |
229 | self.write_str("[")?; | |
230 | self = self.print_type(ty)?; | |
231 | self.write_str("; ")?; | |
923072b8 | 232 | if let Some(size) = size.kind().try_to_bits(self.tcx().data_layout.pointer_size) { |
5e7ed085 | 233 | write!(self, "{}", size)? |
923072b8 | 234 | } else if let ty::ConstKind::Param(param) = size.kind() { |
5e7ed085 FG |
235 | self = param.print(self)? |
236 | } else { | |
237 | self.write_str("_")? | |
238 | } | |
239 | self.write_str("]")?; | |
240 | Ok(self) | |
241 | } | |
242 | ||
dc9dc135 XL |
243 | _ => self.pretty_print_type(ty), |
244 | } | |
245 | } | |
246 | ||
247 | fn print_dyn_existential( | |
248 | mut self, | |
cdc7bbd5 | 249 | predicates: &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>>, |
dc9dc135 XL |
250 | ) -> Result<Self::DynExistential, Self::Error> { |
251 | let mut first = true; | |
252 | for p in predicates { | |
253 | if !first { | |
254 | write!(self, "+")?; | |
255 | } | |
256 | first = false; | |
257 | self = p.print(self)?; | |
258 | } | |
259 | Ok(self) | |
260 | } | |
261 | ||
5099ac24 | 262 | fn print_const(self, ct: ty::Const<'tcx>) -> Result<Self::Const, Self::Error> { |
dc9dc135 | 263 | // only print integers |
923072b8 FG |
264 | match (ct.kind(), ct.ty().kind()) { |
265 | (ty::ConstKind::Value(ty::ValTree::Leaf(scalar)), ty::Int(_) | ty::Uint(_)) => { | |
5e7ed085 FG |
266 | // The `pretty_print_const` formatting depends on -Zverbose |
267 | // flag, so we cannot reuse it here. | |
268 | let signed = matches!(ct.ty().kind(), ty::Int(_)); | |
269 | write!( | |
270 | self, | |
271 | "{:#?}", | |
272 | ty::ConstInt::new(scalar, signed, ct.ty().is_ptr_sized_integral()) | |
273 | )?; | |
dc9dc135 | 274 | } |
5e7ed085 | 275 | _ => self.write_str("_")?, |
dc9dc135 | 276 | } |
dc9dc135 XL |
277 | Ok(self) |
278 | } | |
279 | ||
94222f64 | 280 | fn path_crate(self, cnum: CrateNum) -> Result<Self::Path, Self::Error> { |
a2a8927a | 281 | self.write_str(self.tcx.crate_name(cnum).as_str())?; |
dc9dc135 XL |
282 | Ok(self) |
283 | } | |
284 | fn path_qualified( | |
285 | self, | |
286 | self_ty: Ty<'tcx>, | |
287 | trait_ref: Option<ty::TraitRef<'tcx>>, | |
288 | ) -> Result<Self::Path, Self::Error> { | |
289 | // Similar to `pretty_path_qualified`, but for the other | |
290 | // types that are printed as paths (see `print_type` above). | |
1b1a35ee | 291 | match self_ty.kind() { |
dfeec247 XL |
292 | ty::FnDef(..) |
293 | | ty::Opaque(..) | |
294 | | ty::Projection(_) | |
dfeec247 XL |
295 | | ty::Closure(..) |
296 | | ty::Generator(..) | |
dc9dc135 XL |
297 | if trait_ref.is_none() => |
298 | { | |
299 | self.print_type(self_ty) | |
300 | } | |
301 | ||
dfeec247 | 302 | _ => self.pretty_path_qualified(self_ty, trait_ref), |
dc9dc135 XL |
303 | } |
304 | } | |
305 | ||
306 | fn path_append_impl( | |
307 | self, | |
308 | print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, | |
309 | _disambiguated_data: &DisambiguatedDefPathData, | |
310 | self_ty: Ty<'tcx>, | |
311 | trait_ref: Option<ty::TraitRef<'tcx>>, | |
312 | ) -> Result<Self::Path, Self::Error> { | |
313 | self.pretty_path_append_impl( | |
314 | |mut cx| { | |
315 | cx = print_prefix(cx)?; | |
316 | ||
317 | if cx.keep_within_component { | |
318 | // HACK(eddyb) print the path similarly to how `FmtPrinter` prints it. | |
319 | cx.write_str("::")?; | |
320 | } else { | |
321 | cx.path.finalize_pending_component(); | |
322 | } | |
323 | ||
324 | Ok(cx) | |
325 | }, | |
326 | self_ty, | |
327 | trait_ref, | |
328 | ) | |
329 | } | |
330 | fn path_append( | |
331 | mut self, | |
332 | print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, | |
333 | disambiguated_data: &DisambiguatedDefPathData, | |
334 | ) -> Result<Self::Path, Self::Error> { | |
335 | self = print_prefix(self)?; | |
336 | ||
a2a8927a XL |
337 | // Skip `::{{extern}}` blocks and `::{{constructor}}` on tuple/unit structs. |
338 | if let DefPathData::ForeignMod | DefPathData::Ctor = disambiguated_data.data { | |
ba9703b0 | 339 | return Ok(self); |
dc9dc135 XL |
340 | } |
341 | ||
342 | if self.keep_within_component { | |
343 | // HACK(eddyb) print the path similarly to how `FmtPrinter` prints it. | |
344 | self.write_str("::")?; | |
345 | } else { | |
346 | self.path.finalize_pending_component(); | |
347 | } | |
348 | ||
1b1a35ee XL |
349 | write!(self, "{}", disambiguated_data.data)?; |
350 | ||
dc9dc135 XL |
351 | Ok(self) |
352 | } | |
353 | fn path_generic_args( | |
354 | mut self, | |
355 | print_prefix: impl FnOnce(Self) -> Result<Self::Path, Self::Error>, | |
e74abb32 | 356 | args: &[GenericArg<'tcx>], |
dfeec247 | 357 | ) -> Result<Self::Path, Self::Error> { |
dc9dc135 XL |
358 | self = print_prefix(self)?; |
359 | ||
29967ef6 XL |
360 | let args = |
361 | args.iter().cloned().filter(|arg| !matches!(arg.unpack(), GenericArgKind::Lifetime(_))); | |
dc9dc135 XL |
362 | |
363 | if args.clone().next().is_some() { | |
364 | self.generic_delimiters(|cx| cx.comma_sep(args)) | |
365 | } else { | |
366 | Ok(self) | |
367 | } | |
368 | } | |
369 | } | |
370 | ||
a2a8927a | 371 | impl<'tcx> PrettyPrinter<'tcx> for &mut SymbolPrinter<'tcx> { |
5e7ed085 | 372 | fn should_print_region(&self, _region: ty::Region<'_>) -> bool { |
dc9dc135 XL |
373 | false |
374 | } | |
375 | fn comma_sep<T>(mut self, mut elems: impl Iterator<Item = T>) -> Result<Self, Self::Error> | |
376 | where | |
377 | T: Print<'tcx, Self, Output = Self, Error = Self::Error>, | |
378 | { | |
379 | if let Some(first) = elems.next() { | |
380 | self = first.print(self)?; | |
381 | for elem in elems { | |
382 | self.write_str(",")?; | |
383 | self = elem.print(self)?; | |
384 | } | |
385 | } | |
386 | Ok(self) | |
387 | } | |
388 | ||
389 | fn generic_delimiters( | |
390 | mut self, | |
391 | f: impl FnOnce(Self) -> Result<Self, Self::Error>, | |
392 | ) -> Result<Self, Self::Error> { | |
393 | write!(self, "<")?; | |
394 | ||
dfeec247 | 395 | let kept_within_component = mem::replace(&mut self.keep_within_component, true); |
dc9dc135 XL |
396 | self = f(self)?; |
397 | self.keep_within_component = kept_within_component; | |
398 | ||
399 | write!(self, ">")?; | |
400 | ||
401 | Ok(self) | |
402 | } | |
403 | } | |
404 | ||
405 | impl fmt::Write for SymbolPrinter<'_> { | |
406 | fn write_str(&mut self, s: &str) -> fmt::Result { | |
407 | // Name sanitation. LLVM will happily accept identifiers with weird names, but | |
408 | // gas doesn't! | |
409 | // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $ | |
410 | // NVPTX assembly has more strict naming rules than gas, so additionally, dots | |
411 | // are replaced with '$' there. | |
412 | ||
413 | for c in s.chars() { | |
414 | if self.path.temp_buf.is_empty() { | |
415 | match c { | |
416 | 'a'..='z' | 'A'..='Z' | '_' => {} | |
417 | _ => { | |
418 | // Underscore-qualify anything that didn't start as an ident. | |
419 | self.path.temp_buf.push('_'); | |
420 | } | |
421 | } | |
422 | } | |
423 | match c { | |
424 | // Escape these with $ sequences | |
425 | '@' => self.path.temp_buf.push_str("$SP$"), | |
426 | '*' => self.path.temp_buf.push_str("$BP$"), | |
427 | '&' => self.path.temp_buf.push_str("$RF$"), | |
428 | '<' => self.path.temp_buf.push_str("$LT$"), | |
429 | '>' => self.path.temp_buf.push_str("$GT$"), | |
430 | '(' => self.path.temp_buf.push_str("$LP$"), | |
431 | ')' => self.path.temp_buf.push_str("$RP$"), | |
432 | ',' => self.path.temp_buf.push_str("$C$"), | |
433 | ||
434 | '-' | ':' | '.' if self.tcx.has_strict_asm_symbol_naming() => { | |
435 | // NVPTX doesn't support these characters in symbol names. | |
436 | self.path.temp_buf.push('$') | |
437 | } | |
438 | ||
439 | // '.' doesn't occur in types and functions, so reuse it | |
440 | // for ':' and '-' | |
441 | '-' | ':' => self.path.temp_buf.push('.'), | |
442 | ||
443 | // Avoid crashing LLVM in certain (LTO-related) situations, see #60925. | |
444 | 'm' if self.path.temp_buf.ends_with(".llv") => self.path.temp_buf.push_str("$u6d$"), | |
445 | ||
446 | // These are legal symbols | |
447 | 'a'..='z' | 'A'..='Z' | '0'..='9' | '_' | '.' | '$' => self.path.temp_buf.push(c), | |
448 | ||
449 | _ => { | |
450 | self.path.temp_buf.push('$'); | |
451 | for c in c.escape_unicode().skip(1) { | |
452 | match c { | |
453 | '{' => {} | |
454 | '}' => self.path.temp_buf.push('$'), | |
455 | c => self.path.temp_buf.push(c), | |
456 | } | |
457 | } | |
458 | } | |
459 | } | |
460 | } | |
461 | ||
462 | Ok(()) | |
463 | } | |
464 | } |