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Commit | Line | Data |
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dfeec247 | 1 | use crate::middle::codegen_fn_attrs::CodegenFnAttrFlags; |
dfeec247 | 2 | use crate::ty::print::{FmtPrinter, Printer}; |
2b03887a FG |
3 | use crate::ty::{self, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitable}; |
4 | use crate::ty::{EarlyBinder, InternalSubsts, SubstsRef}; | |
5e7ed085 | 5 | use rustc_errors::ErrorGuaranteed; |
dfeec247 XL |
6 | use rustc_hir::def::Namespace; |
7 | use rustc_hir::def_id::{CrateNum, DefId}; | |
3dfed10e | 8 | use rustc_hir::lang_items::LangItem; |
532ac7d7 | 9 | use rustc_macros::HashStable; |
a2a8927a | 10 | use rustc_middle::ty::normalize_erasing_regions::NormalizationError; |
04454e1e | 11 | use rustc_span::Symbol; |
cc61c64b XL |
12 | |
13 | use std::fmt; | |
14 | ||
f035d41b XL |
15 | /// A monomorphized `InstanceDef`. |
16 | /// | |
17 | /// Monomorphization happens on-the-fly and no monomorphized MIR is ever created. Instead, this type | |
18 | /// simply couples a potentially generic `InstanceDef` with some substs, and codegen and const eval | |
19 | /// will do all required substitution as they run. | |
3dfed10e | 20 | #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)] |
f2b60f7d | 21 | #[derive(HashStable, Lift, TypeFoldable, TypeVisitable)] |
cc61c64b XL |
22 | pub struct Instance<'tcx> { |
23 | pub def: InstanceDef<'tcx>, | |
532ac7d7 | 24 | pub substs: SubstsRef<'tcx>, |
cc61c64b XL |
25 | } |
26 | ||
29967ef6 | 27 | #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] |
f2b60f7d | 28 | #[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable, Lift)] |
cc61c64b | 29 | pub enum InstanceDef<'tcx> { |
f035d41b XL |
30 | /// A user-defined callable item. |
31 | /// | |
32 | /// This includes: | |
33 | /// - `fn` items | |
34 | /// - closures | |
35 | /// - generators | |
3dfed10e | 36 | Item(ty::WithOptConstParam<DefId>), |
f035d41b XL |
37 | |
38 | /// An intrinsic `fn` item (with `"rust-intrinsic"` or `"platform-intrinsic"` ABI). | |
39 | /// | |
40 | /// Alongside `Virtual`, this is the only `InstanceDef` that does not have its own callable MIR. | |
41 | /// Instead, codegen and const eval "magically" evaluate calls to intrinsics purely in the | |
42 | /// caller. | |
cc61c64b | 43 | Intrinsic(DefId), |
3b2f2976 | 44 | |
f035d41b XL |
45 | /// `<T as Trait>::method` where `method` receives unsizeable `self: Self` (part of the |
46 | /// `unsized_locals` feature). | |
47 | /// | |
48 | /// The generated shim will take `Self` via `*mut Self` - conceptually this is `&owned Self` - | |
49 | /// and dereference the argument to call the original function. | |
064997fb | 50 | VTableShim(DefId), |
a1dfa0c6 | 51 | |
e74abb32 XL |
52 | /// `fn()` pointer where the function itself cannot be turned into a pointer. |
53 | /// | |
60c5eb7d XL |
54 | /// One example is `<dyn Trait as Trait>::fn`, where the shim contains |
55 | /// a virtual call, which codegen supports only via a direct call to the | |
56 | /// `<dyn Trait as Trait>::fn` instance (an `InstanceDef::Virtual`). | |
57 | /// | |
58 | /// Another example is functions annotated with `#[track_caller]`, which | |
59 | /// must have their implicit caller location argument populated for a call. | |
60 | /// Because this is a required part of the function's ABI but can't be tracked | |
61 | /// as a property of the function pointer, we use a single "caller location" | |
62 | /// (the definition of the function itself). | |
e74abb32 XL |
63 | ReifyShim(DefId), |
64 | ||
f035d41b XL |
65 | /// `<fn() as FnTrait>::call_*` (generated `FnTrait` implementation for `fn()` pointers). |
66 | /// | |
60c5eb7d | 67 | /// `DefId` is `FnTrait::call_*`. |
cc61c64b | 68 | FnPtrShim(DefId, Ty<'tcx>), |
3b2f2976 | 69 | |
f035d41b | 70 | /// Dynamic dispatch to `<dyn Trait as Trait>::fn`. |
60c5eb7d | 71 | /// |
f035d41b XL |
72 | /// This `InstanceDef` does not have callable MIR. Calls to `Virtual` instances must be |
73 | /// codegen'd as virtual calls through the vtable. | |
74 | /// | |
75 | /// If this is reified to a `fn` pointer, a `ReifyShim` is used (see `ReifyShim` above for more | |
76 | /// details on that). | |
cc61c64b | 77 | Virtual(DefId, usize), |
3b2f2976 | 78 | |
f035d41b XL |
79 | /// `<[FnMut closure] as FnOnce>::call_once`. |
80 | /// | |
81 | /// The `DefId` is the ID of the `call_once` method in `FnOnce`. | |
c295e0f8 | 82 | ClosureOnceShim { call_once: DefId, track_caller: bool }, |
3b2f2976 | 83 | |
74b04a01 | 84 | /// `core::ptr::drop_in_place::<T>`. |
f035d41b | 85 | /// |
74b04a01 XL |
86 | /// The `DefId` is for `core::ptr::drop_in_place`. |
87 | /// The `Option<Ty<'tcx>>` is either `Some(T)`, or `None` for empty drop | |
88 | /// glue. | |
cc61c64b | 89 | DropGlue(DefId, Option<Ty<'tcx>>), |
3b2f2976 | 90 | |
f035d41b XL |
91 | /// Compiler-generated `<T as Clone>::clone` implementation. |
92 | /// | |
93 | /// For all types that automatically implement `Copy`, a trivial `Clone` impl is provided too. | |
94 | /// Additionally, arrays, tuples, and closures get a `Clone` shim even if they aren't `Copy`. | |
95 | /// | |
96 | /// The `DefId` is for `Clone::clone`, the `Ty` is the type `T` with the builtin `Clone` impl. | |
3b2f2976 | 97 | CloneShim(DefId, Ty<'tcx>), |
cc61c64b XL |
98 | } |
99 | ||
dc9dc135 | 100 | impl<'tcx> Instance<'tcx> { |
3dfed10e XL |
101 | /// Returns the `Ty` corresponding to this `Instance`, with generic substitutions applied and |
102 | /// lifetimes erased, allowing a `ParamEnv` to be specified for use during normalization. | |
103 | pub fn ty(&self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Ty<'tcx> { | |
ff7c6d11 | 104 | let ty = tcx.type_of(self.def.def_id()); |
5099ac24 | 105 | tcx.subst_and_normalize_erasing_regions(self.substs, param_env, ty) |
dfeec247 XL |
106 | } |
107 | ||
108 | /// Finds a crate that contains a monomorphization of this instance that | |
109 | /// can be linked to from the local crate. A return value of `None` means | |
110 | /// no upstream crate provides such an exported monomorphization. | |
111 | /// | |
112 | /// This method already takes into account the global `-Zshare-generics` | |
113 | /// setting, always returning `None` if `share-generics` is off. | |
114 | pub fn upstream_monomorphization(&self, tcx: TyCtxt<'tcx>) -> Option<CrateNum> { | |
115 | // If we are not in share generics mode, we don't link to upstream | |
116 | // monomorphizations but always instantiate our own internal versions | |
117 | // instead. | |
118 | if !tcx.sess.opts.share_generics() { | |
119 | return None; | |
120 | } | |
121 | ||
122 | // If this is an item that is defined in the local crate, no upstream | |
123 | // crate can know about it/provide a monomorphization. | |
124 | if self.def_id().is_local() { | |
125 | return None; | |
126 | } | |
127 | ||
128 | // If this a non-generic instance, it cannot be a shared monomorphization. | |
74b04a01 | 129 | self.substs.non_erasable_generics().next()?; |
dfeec247 XL |
130 | |
131 | match self.def { | |
3dfed10e XL |
132 | InstanceDef::Item(def) => tcx |
133 | .upstream_monomorphizations_for(def.did) | |
dfeec247 XL |
134 | .and_then(|monos| monos.get(&self.substs).cloned()), |
135 | InstanceDef::DropGlue(_, Some(_)) => tcx.upstream_drop_glue_for(self.substs), | |
136 | _ => None, | |
137 | } | |
ff7c6d11 XL |
138 | } |
139 | } | |
140 | ||
cc61c64b XL |
141 | impl<'tcx> InstanceDef<'tcx> { |
142 | #[inline] | |
3dfed10e XL |
143 | pub fn def_id(self) -> DefId { |
144 | match self { | |
145 | InstanceDef::Item(def) => def.did, | |
064997fb | 146 | InstanceDef::VTableShim(def_id) |
dfeec247 XL |
147 | | InstanceDef::ReifyShim(def_id) |
148 | | InstanceDef::FnPtrShim(def_id, _) | |
149 | | InstanceDef::Virtual(def_id, _) | |
150 | | InstanceDef::Intrinsic(def_id) | |
c295e0f8 | 151 | | InstanceDef::ClosureOnceShim { call_once: def_id, track_caller: _ } |
dfeec247 XL |
152 | | InstanceDef::DropGlue(def_id, _) |
153 | | InstanceDef::CloneShim(def_id, _) => def_id, | |
cc61c64b XL |
154 | } |
155 | } | |
156 | ||
c295e0f8 XL |
157 | /// Returns the `DefId` of instances which might not require codegen locally. |
158 | pub fn def_id_if_not_guaranteed_local_codegen(self) -> Option<DefId> { | |
159 | match self { | |
160 | ty::InstanceDef::Item(def) => Some(def.did), | |
161 | ty::InstanceDef::DropGlue(def_id, Some(_)) => Some(def_id), | |
064997fb | 162 | InstanceDef::VTableShim(..) |
c295e0f8 XL |
163 | | InstanceDef::ReifyShim(..) |
164 | | InstanceDef::FnPtrShim(..) | |
165 | | InstanceDef::Virtual(..) | |
166 | | InstanceDef::Intrinsic(..) | |
167 | | InstanceDef::ClosureOnceShim { .. } | |
168 | | InstanceDef::DropGlue(..) | |
169 | | InstanceDef::CloneShim(..) => None, | |
170 | } | |
171 | } | |
172 | ||
3dfed10e XL |
173 | #[inline] |
174 | pub fn with_opt_param(self) -> ty::WithOptConstParam<DefId> { | |
175 | match self { | |
176 | InstanceDef::Item(def) => def, | |
064997fb | 177 | InstanceDef::VTableShim(def_id) |
3dfed10e XL |
178 | | InstanceDef::ReifyShim(def_id) |
179 | | InstanceDef::FnPtrShim(def_id, _) | |
180 | | InstanceDef::Virtual(def_id, _) | |
181 | | InstanceDef::Intrinsic(def_id) | |
c295e0f8 | 182 | | InstanceDef::ClosureOnceShim { call_once: def_id, track_caller: _ } |
3dfed10e XL |
183 | | InstanceDef::DropGlue(def_id, _) |
184 | | InstanceDef::CloneShim(def_id, _) => ty::WithOptConstParam::unknown(def_id), | |
185 | } | |
186 | } | |
187 | ||
cc61c64b | 188 | #[inline] |
04454e1e FG |
189 | pub fn get_attrs(&self, tcx: TyCtxt<'tcx>, attr: Symbol) -> ty::Attributes<'tcx> { |
190 | tcx.get_attrs(self.def_id(), attr) | |
cc61c64b | 191 | } |
ff7c6d11 | 192 | |
dfeec247 XL |
193 | /// Returns `true` if the LLVM version of this instance is unconditionally |
194 | /// marked with `inline`. This implies that a copy of this instance is | |
195 | /// generated in every codegen unit. | |
196 | /// Note that this is only a hint. See the documentation for | |
197 | /// `generates_cgu_internal_copy` for more information. | |
198 | pub fn requires_inline(&self, tcx: TyCtxt<'tcx>) -> bool { | |
ba9703b0 | 199 | use rustc_hir::definitions::DefPathData; |
ff7c6d11 | 200 | let def_id = match *self { |
3dfed10e | 201 | ty::InstanceDef::Item(def) => def.did, |
ff7c6d11 | 202 | ty::InstanceDef::DropGlue(_, Some(_)) => return false, |
dfeec247 | 203 | _ => return true, |
ff7c6d11 | 204 | }; |
29967ef6 XL |
205 | matches!( |
206 | tcx.def_key(def_id).disambiguated_data.data, | |
207 | DefPathData::Ctor | DefPathData::ClosureExpr | |
208 | ) | |
ff7c6d11 XL |
209 | } |
210 | ||
dfeec247 XL |
211 | /// Returns `true` if the machine code for this instance is instantiated in |
212 | /// each codegen unit that references it. | |
213 | /// Note that this is only a hint! The compiler can globally decide to *not* | |
214 | /// do this in order to speed up compilation. CGU-internal copies are | |
215 | /// only exist to enable inlining. If inlining is not performed (e.g. at | |
216 | /// `-Copt-level=0`) then the time for generating them is wasted and it's | |
217 | /// better to create a single copy with external linkage. | |
218 | pub fn generates_cgu_internal_copy(&self, tcx: TyCtxt<'tcx>) -> bool { | |
219 | if self.requires_inline(tcx) { | |
220 | return true; | |
ff7c6d11 | 221 | } |
74b04a01 XL |
222 | if let ty::InstanceDef::DropGlue(.., Some(ty)) = *self { |
223 | // Drop glue generally wants to be instantiated at every codegen | |
ff7c6d11 XL |
224 | // unit, but without an #[inline] hint. We should make this |
225 | // available to normal end-users. | |
74b04a01 XL |
226 | if tcx.sess.opts.incremental.is_none() { |
227 | return true; | |
228 | } | |
229 | // When compiling with incremental, we can generate a *lot* of | |
230 | // codegen units. Including drop glue into all of them has a | |
231 | // considerable compile time cost. | |
232 | // | |
233 | // We include enums without destructors to allow, say, optimizing | |
234 | // drops of `Option::None` before LTO. We also respect the intent of | |
235 | // `#[inline]` on `Drop::drop` implementations. | |
236 | return ty.ty_adt_def().map_or(true, |adt_def| { | |
cdc7bbd5 XL |
237 | adt_def.destructor(tcx).map_or_else( |
238 | || adt_def.is_enum(), | |
239 | |dtor| tcx.codegen_fn_attrs(dtor.did).requests_inline(), | |
240 | ) | |
74b04a01 | 241 | }); |
ff7c6d11 | 242 | } |
a1dfa0c6 | 243 | tcx.codegen_fn_attrs(self.def_id()).requests_inline() |
ff7c6d11 | 244 | } |
60c5eb7d XL |
245 | |
246 | pub fn requires_caller_location(&self, tcx: TyCtxt<'_>) -> bool { | |
dfeec247 | 247 | match *self { |
136023e0 XL |
248 | InstanceDef::Item(ty::WithOptConstParam { did: def_id, .. }) |
249 | | InstanceDef::Virtual(def_id, _) => { | |
04454e1e | 250 | tcx.body_codegen_attrs(def_id).flags.contains(CodegenFnAttrFlags::TRACK_CALLER) |
dfeec247 | 251 | } |
c295e0f8 | 252 | InstanceDef::ClosureOnceShim { call_once: _, track_caller } => track_caller, |
dfeec247 XL |
253 | _ => false, |
254 | } | |
60c5eb7d | 255 | } |
1b1a35ee XL |
256 | |
257 | /// Returns `true` when the MIR body associated with this instance should be monomorphized | |
258 | /// by its users (e.g. codegen or miri) by substituting the `substs` from `Instance` (see | |
259 | /// `Instance::substs_for_mir_body`). | |
260 | /// | |
261 | /// Otherwise, returns `false` only for some kinds of shims where the construction of the MIR | |
262 | /// body should perform necessary substitutions. | |
263 | pub fn has_polymorphic_mir_body(&self) -> bool { | |
264 | match *self { | |
265 | InstanceDef::CloneShim(..) | |
266 | | InstanceDef::FnPtrShim(..) | |
267 | | InstanceDef::DropGlue(_, Some(_)) => false, | |
268 | InstanceDef::ClosureOnceShim { .. } | |
269 | | InstanceDef::DropGlue(..) | |
270 | | InstanceDef::Item(_) | |
271 | | InstanceDef::Intrinsic(..) | |
272 | | InstanceDef::ReifyShim(..) | |
273 | | InstanceDef::Virtual(..) | |
064997fb | 274 | | InstanceDef::VTableShim(..) => true, |
1b1a35ee XL |
275 | } |
276 | } | |
cc61c64b XL |
277 | } |
278 | ||
279 | impl<'tcx> fmt::Display for Instance<'tcx> { | |
0bf4aa26 | 280 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
532ac7d7 | 281 | ty::tls::with(|tcx| { |
29967ef6 | 282 | let substs = tcx.lift(self.substs).expect("could not lift for printing"); |
5e7ed085 FG |
283 | let s = FmtPrinter::new(tcx, Namespace::ValueNS) |
284 | .print_def_path(self.def_id(), substs)? | |
285 | .into_buffer(); | |
286 | f.write_str(&s) | |
532ac7d7 XL |
287 | })?; |
288 | ||
cc61c64b XL |
289 | match self.def { |
290 | InstanceDef::Item(_) => Ok(()), | |
064997fb | 291 | InstanceDef::VTableShim(_) => write!(f, " - shim(vtable)"), |
dfeec247 XL |
292 | InstanceDef::ReifyShim(_) => write!(f, " - shim(reify)"), |
293 | InstanceDef::Intrinsic(_) => write!(f, " - intrinsic"), | |
294 | InstanceDef::Virtual(_, num) => write!(f, " - virtual#{}", num), | |
1b1a35ee | 295 | InstanceDef::FnPtrShim(_, ty) => write!(f, " - shim({})", ty), |
dfeec247 | 296 | InstanceDef::ClosureOnceShim { .. } => write!(f, " - shim"), |
1b1a35ee XL |
297 | InstanceDef::DropGlue(_, None) => write!(f, " - shim(None)"), |
298 | InstanceDef::DropGlue(_, Some(ty)) => write!(f, " - shim(Some({}))", ty), | |
299 | InstanceDef::CloneShim(_, ty) => write!(f, " - shim({})", ty), | |
cc61c64b XL |
300 | } |
301 | } | |
302 | } | |
303 | ||
dc9dc135 | 304 | impl<'tcx> Instance<'tcx> { |
dfeec247 XL |
305 | pub fn new(def_id: DefId, substs: SubstsRef<'tcx>) -> Instance<'tcx> { |
306 | assert!( | |
307 | !substs.has_escaping_bound_vars(), | |
308 | "substs of instance {:?} not normalized for codegen: {:?}", | |
309 | def_id, | |
310 | substs | |
311 | ); | |
3dfed10e | 312 | Instance { def: InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), substs } |
cc61c64b XL |
313 | } |
314 | ||
dc9dc135 | 315 | pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx> { |
29967ef6 XL |
316 | let substs = InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind { |
317 | ty::GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(), | |
318 | ty::GenericParamDefKind::Type { .. } => { | |
319 | bug!("Instance::mono: {:?} has type parameters", def_id) | |
320 | } | |
321 | ty::GenericParamDefKind::Const { .. } => { | |
322 | bug!("Instance::mono: {:?} has const parameters", def_id) | |
323 | } | |
324 | }); | |
325 | ||
326 | Instance::new(def_id, substs) | |
cc61c64b XL |
327 | } |
328 | ||
329 | #[inline] | |
330 | pub fn def_id(&self) -> DefId { | |
331 | self.def.def_id() | |
332 | } | |
ea8adc8c | 333 | |
9fa01778 | 334 | /// Resolves a `(def_id, substs)` pair to an (optional) instance -- most commonly, |
ea8adc8c XL |
335 | /// this is used to find the precise code that will run for a trait method invocation, |
336 | /// if known. | |
337 | /// | |
f9f354fc | 338 | /// Returns `Ok(None)` if we cannot resolve `Instance` to a specific instance. |
ea8adc8c XL |
339 | /// For example, in a context like this, |
340 | /// | |
04454e1e | 341 | /// ```ignore (illustrative) |
ea8adc8c XL |
342 | /// fn foo<T: Debug>(t: T) { ... } |
343 | /// ``` | |
344 | /// | |
f9f354fc | 345 | /// trying to resolve `Debug::fmt` applied to `T` will yield `Ok(None)`, because we do not |
ea8adc8c XL |
346 | /// know what code ought to run. (Note that this setting is also affected by the |
347 | /// `RevealMode` in the parameter environment.) | |
348 | /// | |
349 | /// Presuming that coherence and type-check have succeeded, if this method is invoked | |
94b46f34 | 350 | /// in a monomorphic context (i.e., like during codegen), then it is guaranteed to return |
f9f354fc XL |
351 | /// `Ok(Some(instance))`. |
352 | /// | |
5e7ed085 | 353 | /// Returns `Err(ErrorGuaranteed)` when the `Instance` resolution process |
f9f354fc XL |
354 | /// couldn't complete due to errors elsewhere - this is distinct |
355 | /// from `Ok(None)` to avoid misleading diagnostics when an error | |
356 | /// has already been/will be emitted, for the original cause | |
dc9dc135 XL |
357 | pub fn resolve( |
358 | tcx: TyCtxt<'tcx>, | |
359 | param_env: ty::ParamEnv<'tcx>, | |
360 | def_id: DefId, | |
361 | substs: SubstsRef<'tcx>, | |
5e7ed085 | 362 | ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> { |
3dfed10e XL |
363 | Instance::resolve_opt_const_arg( |
364 | tcx, | |
365 | param_env, | |
366 | ty::WithOptConstParam::unknown(def_id), | |
367 | substs, | |
368 | ) | |
369 | } | |
370 | ||
371 | // This should be kept up to date with `resolve`. | |
372 | pub fn resolve_opt_const_arg( | |
373 | tcx: TyCtxt<'tcx>, | |
374 | param_env: ty::ParamEnv<'tcx>, | |
375 | def: ty::WithOptConstParam<DefId>, | |
376 | substs: SubstsRef<'tcx>, | |
5e7ed085 | 377 | ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> { |
ba9703b0 XL |
378 | // All regions in the result of this query are erased, so it's |
379 | // fine to erase all of the input regions. | |
f9f354fc XL |
380 | |
381 | // HACK(eddyb) erase regions in `substs` first, so that `param_env.and(...)` | |
382 | // below is more likely to ignore the bounds in scope (e.g. if the only | |
383 | // generic parameters mentioned by `substs` were lifetime ones). | |
fc512014 | 384 | let substs = tcx.erase_regions(substs); |
f9f354fc XL |
385 | |
386 | // FIXME(eddyb) should this always use `param_env.with_reveal_all()`? | |
3dfed10e XL |
387 | if let Some((did, param_did)) = def.as_const_arg() { |
388 | tcx.resolve_instance_of_const_arg( | |
fc512014 | 389 | tcx.erase_regions(param_env.and((did, param_did, substs))), |
3dfed10e XL |
390 | ) |
391 | } else { | |
fc512014 | 392 | tcx.resolve_instance(tcx.erase_regions(param_env.and((def.did, substs)))) |
3dfed10e | 393 | } |
ea8adc8c | 394 | } |
ea8adc8c | 395 | |
e74abb32 XL |
396 | pub fn resolve_for_fn_ptr( |
397 | tcx: TyCtxt<'tcx>, | |
398 | param_env: ty::ParamEnv<'tcx>, | |
399 | def_id: DefId, | |
400 | substs: SubstsRef<'tcx>, | |
401 | ) -> Option<Instance<'tcx>> { | |
402 | debug!("resolve(def_id={:?}, substs={:?})", def_id, substs); | |
c295e0f8 XL |
403 | // Use either `resolve_closure` or `resolve_for_vtable` |
404 | assert!(!tcx.is_closure(def_id), "Called `resolve_for_fn_ptr` on closure: {:?}", def_id); | |
f9f354fc | 405 | Instance::resolve(tcx, param_env, def_id, substs).ok().flatten().map(|mut resolved| { |
e74abb32 | 406 | match resolved.def { |
3dfed10e | 407 | InstanceDef::Item(def) if resolved.def.requires_caller_location(tcx) => { |
e74abb32 | 408 | debug!(" => fn pointer created for function with #[track_caller]"); |
3dfed10e | 409 | resolved.def = InstanceDef::ReifyShim(def.did); |
60c5eb7d XL |
410 | } |
411 | InstanceDef::Virtual(def_id, _) => { | |
412 | debug!(" => fn pointer created for virtual call"); | |
413 | resolved.def = InstanceDef::ReifyShim(def_id); | |
414 | } | |
415 | _ => {} | |
e74abb32 | 416 | } |
60c5eb7d XL |
417 | |
418 | resolved | |
e74abb32 XL |
419 | }) |
420 | } | |
421 | ||
dc9dc135 XL |
422 | pub fn resolve_for_vtable( |
423 | tcx: TyCtxt<'tcx>, | |
424 | param_env: ty::ParamEnv<'tcx>, | |
425 | def_id: DefId, | |
426 | substs: SubstsRef<'tcx>, | |
427 | ) -> Option<Instance<'tcx>> { | |
136023e0 | 428 | debug!("resolve_for_vtable(def_id={:?}, substs={:?})", def_id, substs); |
a1dfa0c6 | 429 | let fn_sig = tcx.fn_sig(def_id); |
74b04a01 | 430 | let is_vtable_shim = !fn_sig.inputs().skip_binder().is_empty() |
e1599b0c XL |
431 | && fn_sig.input(0).skip_binder().is_param(0) |
432 | && tcx.generics_of(def_id).has_self; | |
a1dfa0c6 XL |
433 | if is_vtable_shim { |
434 | debug!(" => associated item with unsizeable self: Self"); | |
064997fb | 435 | Some(Instance { def: InstanceDef::VTableShim(def_id), substs }) |
a1dfa0c6 | 436 | } else { |
136023e0 XL |
437 | Instance::resolve(tcx, param_env, def_id, substs).ok().flatten().map(|mut resolved| { |
438 | match resolved.def { | |
439 | InstanceDef::Item(def) => { | |
440 | // We need to generate a shim when we cannot guarantee that | |
441 | // the caller of a trait object method will be aware of | |
442 | // `#[track_caller]` - this ensures that the caller | |
443 | // and callee ABI will always match. | |
444 | // | |
445 | // The shim is generated when all of these conditions are met: | |
446 | // | |
447 | // 1) The underlying method expects a caller location parameter | |
448 | // in the ABI | |
449 | if resolved.def.requires_caller_location(tcx) | |
450 | // 2) The caller location parameter comes from having `#[track_caller]` | |
451 | // on the implementation, and *not* on the trait method. | |
452 | && !tcx.should_inherit_track_caller(def.did) | |
453 | // If the method implementation comes from the trait definition itself | |
454 | // (e.g. `trait Foo { #[track_caller] my_fn() { /* impl */ } }`), | |
455 | // then we don't need to generate a shim. This check is needed because | |
456 | // `should_inherit_track_caller` returns `false` if our method | |
457 | // implementation comes from the trait block, and not an impl block | |
458 | && !matches!( | |
459 | tcx.opt_associated_item(def.did), | |
460 | Some(ty::AssocItem { | |
064997fb | 461 | container: ty::AssocItemContainer::TraitContainer, |
136023e0 XL |
462 | .. |
463 | }) | |
464 | ) | |
465 | { | |
c295e0f8 XL |
466 | if tcx.is_closure(def.did) { |
467 | debug!(" => vtable fn pointer created for closure with #[track_caller]: {:?} for method {:?} {:?}", | |
468 | def.did, def_id, substs); | |
469 | ||
470 | // Create a shim for the `FnOnce/FnMut/Fn` method we are calling | |
471 | // - unlike functions, invoking a closure always goes through a | |
472 | // trait. | |
473 | resolved = Instance { def: InstanceDef::ReifyShim(def_id), substs }; | |
474 | } else { | |
475 | debug!( | |
476 | " => vtable fn pointer created for function with #[track_caller]: {:?}", def.did | |
477 | ); | |
478 | resolved.def = InstanceDef::ReifyShim(def.did); | |
479 | } | |
136023e0 XL |
480 | } |
481 | } | |
482 | InstanceDef::Virtual(def_id, _) => { | |
483 | debug!(" => vtable fn pointer created for virtual call"); | |
484 | resolved.def = InstanceDef::ReifyShim(def_id); | |
485 | } | |
486 | _ => {} | |
487 | } | |
488 | ||
489 | resolved | |
490 | }) | |
a1dfa0c6 XL |
491 | } |
492 | } | |
493 | ||
ff7c6d11 | 494 | pub fn resolve_closure( |
dc9dc135 | 495 | tcx: TyCtxt<'tcx>, |
0bf4aa26 | 496 | def_id: DefId, |
e74abb32 | 497 | substs: ty::SubstsRef<'tcx>, |
dc9dc135 | 498 | requested_kind: ty::ClosureKind, |
064997fb | 499 | ) -> Option<Instance<'tcx>> { |
ba9703b0 | 500 | let actual_kind = substs.as_closure().kind(); |
ea8adc8c | 501 | |
ff7c6d11 | 502 | match needs_fn_once_adapter_shim(actual_kind, requested_kind) { |
dc9dc135 | 503 | Ok(true) => Instance::fn_once_adapter_instance(tcx, def_id, substs), |
064997fb | 504 | _ => Some(Instance::new(def_id, substs)), |
ff7c6d11 | 505 | } |
ea8adc8c | 506 | } |
a1dfa0c6 | 507 | |
dc9dc135 | 508 | pub fn resolve_drop_in_place(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ty::Instance<'tcx> { |
3dfed10e | 509 | let def_id = tcx.require_lang_item(LangItem::DropInPlace, None); |
dc9dc135 | 510 | let substs = tcx.intern_substs(&[ty.into()]); |
f9f354fc | 511 | Instance::resolve(tcx, ty::ParamEnv::reveal_all(), def_id, substs).unwrap().unwrap() |
dc9dc135 XL |
512 | } |
513 | ||
514 | pub fn fn_once_adapter_instance( | |
515 | tcx: TyCtxt<'tcx>, | |
516 | closure_did: DefId, | |
e74abb32 | 517 | substs: ty::SubstsRef<'tcx>, |
064997fb | 518 | ) -> Option<Instance<'tcx>> { |
dfeec247 | 519 | debug!("fn_once_adapter_shim({:?}, {:?})", closure_did, substs); |
3dfed10e | 520 | let fn_once = tcx.require_lang_item(LangItem::FnOnce, None); |
dfeec247 XL |
521 | let call_once = tcx |
522 | .associated_items(fn_once) | |
74b04a01 | 523 | .in_definition_order() |
ba9703b0 | 524 | .find(|it| it.kind == ty::AssocKind::Fn) |
dfeec247 XL |
525 | .unwrap() |
526 | .def_id; | |
c295e0f8 XL |
527 | let track_caller = |
528 | tcx.codegen_fn_attrs(closure_did).flags.contains(CodegenFnAttrFlags::TRACK_CALLER); | |
529 | let def = ty::InstanceDef::ClosureOnceShim { call_once, track_caller }; | |
dc9dc135 XL |
530 | |
531 | let self_ty = tcx.mk_closure(closure_did, substs); | |
532 | ||
ba9703b0 | 533 | let sig = substs.as_closure().sig(); |
064997fb FG |
534 | let sig = |
535 | tcx.try_normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig).ok()?; | |
dc9dc135 XL |
536 | assert_eq!(sig.inputs().len(), 1); |
537 | let substs = tcx.mk_substs_trait(self_ty, &[sig.inputs()[0].into()]); | |
538 | ||
539 | debug!("fn_once_adapter_shim: self_ty={:?} sig={:?}", self_ty, sig); | |
064997fb | 540 | Some(Instance { def, substs }) |
dc9dc135 XL |
541 | } |
542 | ||
1b1a35ee | 543 | /// Depending on the kind of `InstanceDef`, the MIR body associated with an |
ba9703b0 XL |
544 | /// instance is expressed in terms of the generic parameters of `self.def_id()`, and in other |
545 | /// cases the MIR body is expressed in terms of the types found in the substitution array. | |
546 | /// In the former case, we want to substitute those generic types and replace them with the | |
547 | /// values from the substs when monomorphizing the function body. But in the latter case, we | |
548 | /// don't want to do that substitution, since it has already been done effectively. | |
549 | /// | |
1b1a35ee | 550 | /// This function returns `Some(substs)` in the former case and `None` otherwise -- i.e., if |
ba9703b0 | 551 | /// this function returns `None`, then the MIR body does not require substitution during |
1b1a35ee | 552 | /// codegen. |
29967ef6 | 553 | fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>> { |
1b1a35ee | 554 | if self.def.has_polymorphic_mir_body() { Some(self.substs) } else { None } |
a1dfa0c6 | 555 | } |
3dfed10e | 556 | |
29967ef6 XL |
557 | pub fn subst_mir<T>(&self, tcx: TyCtxt<'tcx>, v: &T) -> T |
558 | where | |
559 | T: TypeFoldable<'tcx> + Copy, | |
560 | { | |
04454e1e FG |
561 | if let Some(substs) = self.substs_for_mir_body() { |
562 | EarlyBinder(*v).subst(tcx, substs) | |
563 | } else { | |
564 | *v | |
565 | } | |
29967ef6 XL |
566 | } |
567 | ||
cdc7bbd5 | 568 | #[inline(always)] |
29967ef6 XL |
569 | pub fn subst_mir_and_normalize_erasing_regions<T>( |
570 | &self, | |
571 | tcx: TyCtxt<'tcx>, | |
572 | param_env: ty::ParamEnv<'tcx>, | |
fc512014 | 573 | v: T, |
29967ef6 XL |
574 | ) -> T |
575 | where | |
576 | T: TypeFoldable<'tcx> + Clone, | |
577 | { | |
578 | if let Some(substs) = self.substs_for_mir_body() { | |
579 | tcx.subst_and_normalize_erasing_regions(substs, param_env, v) | |
580 | } else { | |
fc512014 | 581 | tcx.normalize_erasing_regions(param_env, v) |
29967ef6 XL |
582 | } |
583 | } | |
584 | ||
a2a8927a XL |
585 | #[inline(always)] |
586 | pub fn try_subst_mir_and_normalize_erasing_regions<T>( | |
587 | &self, | |
588 | tcx: TyCtxt<'tcx>, | |
589 | param_env: ty::ParamEnv<'tcx>, | |
590 | v: T, | |
591 | ) -> Result<T, NormalizationError<'tcx>> | |
592 | where | |
593 | T: TypeFoldable<'tcx> + Clone, | |
594 | { | |
595 | if let Some(substs) = self.substs_for_mir_body() { | |
596 | tcx.try_subst_and_normalize_erasing_regions(substs, param_env, v) | |
597 | } else { | |
598 | tcx.try_normalize_erasing_regions(param_env, v) | |
599 | } | |
600 | } | |
601 | ||
3dfed10e | 602 | /// Returns a new `Instance` where generic parameters in `instance.substs` are replaced by |
6a06907d | 603 | /// identity parameters if they are determined to be unused in `instance.def`. |
3dfed10e XL |
604 | pub fn polymorphize(self, tcx: TyCtxt<'tcx>) -> Self { |
605 | debug!("polymorphize: running polymorphization analysis"); | |
064997fb | 606 | if !tcx.sess.opts.unstable_opts.polymorphize { |
3dfed10e XL |
607 | return self; |
608 | } | |
609 | ||
c295e0f8 XL |
610 | let polymorphized_substs = polymorphize(tcx, self.def, self.substs); |
611 | debug!("polymorphize: self={:?} polymorphized_substs={:?}", self, polymorphized_substs); | |
612 | Self { def: self.def, substs: polymorphized_substs } | |
3dfed10e XL |
613 | } |
614 | } | |
615 | ||
616 | fn polymorphize<'tcx>( | |
617 | tcx: TyCtxt<'tcx>, | |
c295e0f8 | 618 | instance: ty::InstanceDef<'tcx>, |
3dfed10e XL |
619 | substs: SubstsRef<'tcx>, |
620 | ) -> SubstsRef<'tcx> { | |
c295e0f8 XL |
621 | debug!("polymorphize({:?}, {:?})", instance, substs); |
622 | let unused = tcx.unused_generic_params(instance); | |
3dfed10e XL |
623 | debug!("polymorphize: unused={:?}", unused); |
624 | ||
625 | // If this is a closure or generator then we need to handle the case where another closure | |
626 | // from the function is captured as an upvar and hasn't been polymorphized. In this case, | |
627 | // the unpolymorphized upvar closure would result in a polymorphized closure producing | |
628 | // multiple mono items (and eventually symbol clashes). | |
c295e0f8 | 629 | let def_id = instance.def_id(); |
3dfed10e XL |
630 | let upvars_ty = if tcx.is_closure(def_id) { |
631 | Some(substs.as_closure().tupled_upvars_ty()) | |
632 | } else if tcx.type_of(def_id).is_generator() { | |
633 | Some(substs.as_generator().tupled_upvars_ty()) | |
634 | } else { | |
635 | None | |
636 | }; | |
5e7ed085 | 637 | let has_upvars = upvars_ty.map_or(false, |ty| !ty.tuple_fields().is_empty()); |
3dfed10e XL |
638 | debug!("polymorphize: upvars_ty={:?} has_upvars={:?}", upvars_ty, has_upvars); |
639 | ||
640 | struct PolymorphizationFolder<'tcx> { | |
641 | tcx: TyCtxt<'tcx>, | |
fc512014 | 642 | } |
3dfed10e | 643 | |
a2a8927a | 644 | impl<'tcx> ty::TypeFolder<'tcx> for PolymorphizationFolder<'tcx> { |
3dfed10e XL |
645 | fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { |
646 | self.tcx | |
647 | } | |
648 | ||
649 | fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
650 | debug!("fold_ty: ty={:?}", ty); | |
5099ac24 | 651 | match *ty.kind() { |
3dfed10e | 652 | ty::Closure(def_id, substs) => { |
c295e0f8 XL |
653 | let polymorphized_substs = polymorphize( |
654 | self.tcx, | |
655 | ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), | |
656 | substs, | |
657 | ); | |
3dfed10e XL |
658 | if substs == polymorphized_substs { |
659 | ty | |
660 | } else { | |
661 | self.tcx.mk_closure(def_id, polymorphized_substs) | |
662 | } | |
663 | } | |
664 | ty::Generator(def_id, substs, movability) => { | |
c295e0f8 XL |
665 | let polymorphized_substs = polymorphize( |
666 | self.tcx, | |
667 | ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), | |
668 | substs, | |
669 | ); | |
3dfed10e XL |
670 | if substs == polymorphized_substs { |
671 | ty | |
672 | } else { | |
673 | self.tcx.mk_generator(def_id, polymorphized_substs, movability) | |
674 | } | |
675 | } | |
676 | _ => ty.super_fold_with(self), | |
677 | } | |
678 | } | |
679 | } | |
680 | ||
681 | InternalSubsts::for_item(tcx, def_id, |param, _| { | |
682 | let is_unused = unused.contains(param.index).unwrap_or(false); | |
683 | debug!("polymorphize: param={:?} is_unused={:?}", param, is_unused); | |
684 | match param.kind { | |
685 | // Upvar case: If parameter is a type parameter.. | |
686 | ty::GenericParamDefKind::Type { .. } if | |
687 | // ..and has upvars.. | |
688 | has_upvars && | |
689 | // ..and this param has the same type as the tupled upvars.. | |
690 | upvars_ty == Some(substs[param.index as usize].expect_ty()) => { | |
691 | // ..then double-check that polymorphization marked it used.. | |
692 | debug_assert!(!is_unused); | |
693 | // ..and polymorphize any closures/generators captured as upvars. | |
694 | let upvars_ty = upvars_ty.unwrap(); | |
695 | let polymorphized_upvars_ty = upvars_ty.fold_with( | |
696 | &mut PolymorphizationFolder { tcx }); | |
697 | debug!("polymorphize: polymorphized_upvars_ty={:?}", polymorphized_upvars_ty); | |
698 | ty::GenericArg::from(polymorphized_upvars_ty) | |
699 | }, | |
700 | ||
701 | // Simple case: If parameter is a const or type parameter.. | |
cdc7bbd5 | 702 | ty::GenericParamDefKind::Const { .. } | ty::GenericParamDefKind::Type { .. } if |
3dfed10e XL |
703 | // ..and is within range and unused.. |
704 | unused.contains(param.index).unwrap_or(false) => | |
705 | // ..then use the identity for this parameter. | |
706 | tcx.mk_param_from_def(param), | |
707 | ||
708 | // Otherwise, use the parameter as before. | |
709 | _ => substs[param.index as usize], | |
710 | } | |
711 | }) | |
ea8adc8c XL |
712 | } |
713 | ||
dc9dc135 XL |
714 | fn needs_fn_once_adapter_shim( |
715 | actual_closure_kind: ty::ClosureKind, | |
716 | trait_closure_kind: ty::ClosureKind, | |
717 | ) -> Result<bool, ()> { | |
ea8adc8c | 718 | match (actual_closure_kind, trait_closure_kind) { |
dfeec247 XL |
719 | (ty::ClosureKind::Fn, ty::ClosureKind::Fn) |
720 | | (ty::ClosureKind::FnMut, ty::ClosureKind::FnMut) | |
721 | | (ty::ClosureKind::FnOnce, ty::ClosureKind::FnOnce) => { | |
722 | // No adapter needed. | |
723 | Ok(false) | |
724 | } | |
ea8adc8c XL |
725 | (ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => { |
726 | // The closure fn `llfn` is a `fn(&self, ...)`. We want a | |
94b46f34 | 727 | // `fn(&mut self, ...)`. In fact, at codegen time, these are |
ea8adc8c XL |
728 | // basically the same thing, so we can just return llfn. |
729 | Ok(false) | |
730 | } | |
ba9703b0 | 731 | (ty::ClosureKind::Fn | ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => { |
dfeec247 XL |
732 | // The closure fn `llfn` is a `fn(&self, ...)` or `fn(&mut |
733 | // self, ...)`. We want a `fn(self, ...)`. We can produce | |
734 | // this by doing something like: | |
735 | // | |
736 | // fn call_once(self, ...) { call_mut(&self, ...) } | |
737 | // fn call_once(mut self, ...) { call_mut(&mut self, ...) } | |
738 | // | |
739 | // These are both the same at codegen time. | |
740 | Ok(true) | |
ea8adc8c | 741 | } |
ba9703b0 | 742 | (ty::ClosureKind::FnMut | ty::ClosureKind::FnOnce, _) => Err(()), |
ea8adc8c XL |
743 | } |
744 | } |