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