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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}; |
29967ef6 | 3 | use crate::ty::subst::{InternalSubsts, Subst}; |
064997fb FG |
4 | use crate::ty::{ |
5 | self, EarlyBinder, SubstsRef, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable, TypeVisitable, | |
6 | }; | |
5e7ed085 | 7 | use rustc_errors::ErrorGuaranteed; |
dfeec247 XL |
8 | use rustc_hir::def::Namespace; |
9 | use rustc_hir::def_id::{CrateNum, DefId}; | |
3dfed10e | 10 | use rustc_hir::lang_items::LangItem; |
532ac7d7 | 11 | use rustc_macros::HashStable; |
a2a8927a | 12 | use rustc_middle::ty::normalize_erasing_regions::NormalizationError; |
04454e1e | 13 | use rustc_span::Symbol; |
cc61c64b XL |
14 | |
15 | use std::fmt; | |
16 | ||
f035d41b XL |
17 | /// A monomorphized `InstanceDef`. |
18 | /// | |
19 | /// Monomorphization happens on-the-fly and no monomorphized MIR is ever created. Instead, this type | |
20 | /// simply couples a potentially generic `InstanceDef` with some substs, and codegen and const eval | |
21 | /// will do all required substitution as they run. | |
3dfed10e | 22 | #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, TyEncodable, TyDecodable)] |
60c5eb7d | 23 | #[derive(HashStable, Lift)] |
cc61c64b XL |
24 | pub struct Instance<'tcx> { |
25 | pub def: InstanceDef<'tcx>, | |
532ac7d7 | 26 | pub substs: SubstsRef<'tcx>, |
cc61c64b XL |
27 | } |
28 | ||
29967ef6 | 29 | #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] |
064997fb | 30 | #[derive(TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)] |
cc61c64b | 31 | pub enum InstanceDef<'tcx> { |
f035d41b XL |
32 | /// A user-defined callable item. |
33 | /// | |
34 | /// This includes: | |
35 | /// - `fn` items | |
36 | /// - closures | |
37 | /// - generators | |
3dfed10e | 38 | Item(ty::WithOptConstParam<DefId>), |
f035d41b XL |
39 | |
40 | /// An intrinsic `fn` item (with `"rust-intrinsic"` or `"platform-intrinsic"` ABI). | |
41 | /// | |
42 | /// Alongside `Virtual`, this is the only `InstanceDef` that does not have its own callable MIR. | |
43 | /// Instead, codegen and const eval "magically" evaluate calls to intrinsics purely in the | |
44 | /// caller. | |
cc61c64b | 45 | Intrinsic(DefId), |
3b2f2976 | 46 | |
f035d41b XL |
47 | /// `<T as Trait>::method` where `method` receives unsizeable `self: Self` (part of the |
48 | /// `unsized_locals` feature). | |
49 | /// | |
50 | /// The generated shim will take `Self` via `*mut Self` - conceptually this is `&owned Self` - | |
51 | /// and dereference the argument to call the original function. | |
064997fb | 52 | VTableShim(DefId), |
a1dfa0c6 | 53 | |
e74abb32 XL |
54 | /// `fn()` pointer where the function itself cannot be turned into a pointer. |
55 | /// | |
60c5eb7d XL |
56 | /// One example is `<dyn Trait as Trait>::fn`, where the shim contains |
57 | /// a virtual call, which codegen supports only via a direct call to the | |
58 | /// `<dyn Trait as Trait>::fn` instance (an `InstanceDef::Virtual`). | |
59 | /// | |
60 | /// Another example is functions annotated with `#[track_caller]`, which | |
61 | /// must have their implicit caller location argument populated for a call. | |
62 | /// Because this is a required part of the function's ABI but can't be tracked | |
63 | /// as a property of the function pointer, we use a single "caller location" | |
64 | /// (the definition of the function itself). | |
e74abb32 XL |
65 | ReifyShim(DefId), |
66 | ||
f035d41b XL |
67 | /// `<fn() as FnTrait>::call_*` (generated `FnTrait` implementation for `fn()` pointers). |
68 | /// | |
60c5eb7d | 69 | /// `DefId` is `FnTrait::call_*`. |
cc61c64b | 70 | FnPtrShim(DefId, Ty<'tcx>), |
3b2f2976 | 71 | |
f035d41b | 72 | /// Dynamic dispatch to `<dyn Trait as Trait>::fn`. |
60c5eb7d | 73 | /// |
f035d41b XL |
74 | /// This `InstanceDef` does not have callable MIR. Calls to `Virtual` instances must be |
75 | /// codegen'd as virtual calls through the vtable. | |
76 | /// | |
77 | /// If this is reified to a `fn` pointer, a `ReifyShim` is used (see `ReifyShim` above for more | |
78 | /// details on that). | |
cc61c64b | 79 | Virtual(DefId, usize), |
3b2f2976 | 80 | |
f035d41b XL |
81 | /// `<[FnMut closure] as FnOnce>::call_once`. |
82 | /// | |
83 | /// The `DefId` is the ID of the `call_once` method in `FnOnce`. | |
c295e0f8 | 84 | ClosureOnceShim { call_once: DefId, track_caller: bool }, |
3b2f2976 | 85 | |
74b04a01 | 86 | /// `core::ptr::drop_in_place::<T>`. |
f035d41b | 87 | /// |
74b04a01 XL |
88 | /// The `DefId` is for `core::ptr::drop_in_place`. |
89 | /// The `Option<Ty<'tcx>>` is either `Some(T)`, or `None` for empty drop | |
90 | /// glue. | |
cc61c64b | 91 | DropGlue(DefId, Option<Ty<'tcx>>), |
3b2f2976 | 92 | |
f035d41b XL |
93 | /// Compiler-generated `<T as Clone>::clone` implementation. |
94 | /// | |
95 | /// For all types that automatically implement `Copy`, a trivial `Clone` impl is provided too. | |
96 | /// Additionally, arrays, tuples, and closures get a `Clone` shim even if they aren't `Copy`. | |
97 | /// | |
98 | /// The `DefId` is for `Clone::clone`, the `Ty` is the type `T` with the builtin `Clone` impl. | |
3b2f2976 | 99 | CloneShim(DefId, Ty<'tcx>), |
cc61c64b XL |
100 | } |
101 | ||
dc9dc135 | 102 | impl<'tcx> Instance<'tcx> { |
3dfed10e XL |
103 | /// Returns the `Ty` corresponding to this `Instance`, with generic substitutions applied and |
104 | /// lifetimes erased, allowing a `ParamEnv` to be specified for use during normalization. | |
105 | pub fn ty(&self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Ty<'tcx> { | |
ff7c6d11 | 106 | let ty = tcx.type_of(self.def.def_id()); |
5099ac24 | 107 | tcx.subst_and_normalize_erasing_regions(self.substs, param_env, ty) |
dfeec247 XL |
108 | } |
109 | ||
110 | /// Finds a crate that contains a monomorphization of this instance that | |
111 | /// can be linked to from the local crate. A return value of `None` means | |
112 | /// no upstream crate provides such an exported monomorphization. | |
113 | /// | |
114 | /// This method already takes into account the global `-Zshare-generics` | |
115 | /// setting, always returning `None` if `share-generics` is off. | |
116 | pub fn upstream_monomorphization(&self, tcx: TyCtxt<'tcx>) -> Option<CrateNum> { | |
117 | // If we are not in share generics mode, we don't link to upstream | |
118 | // monomorphizations but always instantiate our own internal versions | |
119 | // instead. | |
120 | if !tcx.sess.opts.share_generics() { | |
121 | return None; | |
122 | } | |
123 | ||
124 | // If this is an item that is defined in the local crate, no upstream | |
125 | // crate can know about it/provide a monomorphization. | |
126 | if self.def_id().is_local() { | |
127 | return None; | |
128 | } | |
129 | ||
130 | // If this a non-generic instance, it cannot be a shared monomorphization. | |
74b04a01 | 131 | self.substs.non_erasable_generics().next()?; |
dfeec247 XL |
132 | |
133 | match self.def { | |
3dfed10e XL |
134 | InstanceDef::Item(def) => tcx |
135 | .upstream_monomorphizations_for(def.did) | |
dfeec247 XL |
136 | .and_then(|monos| monos.get(&self.substs).cloned()), |
137 | InstanceDef::DropGlue(_, Some(_)) => tcx.upstream_drop_glue_for(self.substs), | |
138 | _ => None, | |
139 | } | |
ff7c6d11 XL |
140 | } |
141 | } | |
142 | ||
cc61c64b XL |
143 | impl<'tcx> InstanceDef<'tcx> { |
144 | #[inline] | |
3dfed10e XL |
145 | pub fn def_id(self) -> DefId { |
146 | match self { | |
147 | InstanceDef::Item(def) => def.did, | |
064997fb | 148 | InstanceDef::VTableShim(def_id) |
dfeec247 XL |
149 | | InstanceDef::ReifyShim(def_id) |
150 | | InstanceDef::FnPtrShim(def_id, _) | |
151 | | InstanceDef::Virtual(def_id, _) | |
152 | | InstanceDef::Intrinsic(def_id) | |
c295e0f8 | 153 | | InstanceDef::ClosureOnceShim { call_once: def_id, track_caller: _ } |
dfeec247 XL |
154 | | InstanceDef::DropGlue(def_id, _) |
155 | | InstanceDef::CloneShim(def_id, _) => def_id, | |
cc61c64b XL |
156 | } |
157 | } | |
158 | ||
c295e0f8 XL |
159 | /// Returns the `DefId` of instances which might not require codegen locally. |
160 | pub fn def_id_if_not_guaranteed_local_codegen(self) -> Option<DefId> { | |
161 | match self { | |
162 | ty::InstanceDef::Item(def) => Some(def.did), | |
163 | ty::InstanceDef::DropGlue(def_id, Some(_)) => Some(def_id), | |
064997fb | 164 | InstanceDef::VTableShim(..) |
c295e0f8 XL |
165 | | InstanceDef::ReifyShim(..) |
166 | | InstanceDef::FnPtrShim(..) | |
167 | | InstanceDef::Virtual(..) | |
168 | | InstanceDef::Intrinsic(..) | |
169 | | InstanceDef::ClosureOnceShim { .. } | |
170 | | InstanceDef::DropGlue(..) | |
171 | | InstanceDef::CloneShim(..) => None, | |
172 | } | |
173 | } | |
174 | ||
3dfed10e XL |
175 | #[inline] |
176 | pub fn with_opt_param(self) -> ty::WithOptConstParam<DefId> { | |
177 | match self { | |
178 | InstanceDef::Item(def) => def, | |
064997fb | 179 | InstanceDef::VTableShim(def_id) |
3dfed10e XL |
180 | | InstanceDef::ReifyShim(def_id) |
181 | | InstanceDef::FnPtrShim(def_id, _) | |
182 | | InstanceDef::Virtual(def_id, _) | |
183 | | InstanceDef::Intrinsic(def_id) | |
c295e0f8 | 184 | | InstanceDef::ClosureOnceShim { call_once: def_id, track_caller: _ } |
3dfed10e XL |
185 | | InstanceDef::DropGlue(def_id, _) |
186 | | InstanceDef::CloneShim(def_id, _) => ty::WithOptConstParam::unknown(def_id), | |
187 | } | |
188 | } | |
189 | ||
cc61c64b | 190 | #[inline] |
04454e1e FG |
191 | pub fn get_attrs(&self, tcx: TyCtxt<'tcx>, attr: Symbol) -> ty::Attributes<'tcx> { |
192 | tcx.get_attrs(self.def_id(), attr) | |
cc61c64b | 193 | } |
ff7c6d11 | 194 | |
dfeec247 XL |
195 | /// Returns `true` if the LLVM version of this instance is unconditionally |
196 | /// marked with `inline`. This implies that a copy of this instance is | |
197 | /// generated in every codegen unit. | |
198 | /// Note that this is only a hint. See the documentation for | |
199 | /// `generates_cgu_internal_copy` for more information. | |
200 | pub fn requires_inline(&self, tcx: TyCtxt<'tcx>) -> bool { | |
ba9703b0 | 201 | use rustc_hir::definitions::DefPathData; |
ff7c6d11 | 202 | let def_id = match *self { |
3dfed10e | 203 | ty::InstanceDef::Item(def) => def.did, |
ff7c6d11 | 204 | ty::InstanceDef::DropGlue(_, Some(_)) => return false, |
dfeec247 | 205 | _ => return true, |
ff7c6d11 | 206 | }; |
29967ef6 XL |
207 | matches!( |
208 | tcx.def_key(def_id).disambiguated_data.data, | |
209 | DefPathData::Ctor | DefPathData::ClosureExpr | |
210 | ) | |
ff7c6d11 XL |
211 | } |
212 | ||
dfeec247 XL |
213 | /// Returns `true` if the machine code for this instance is instantiated in |
214 | /// each codegen unit that references it. | |
215 | /// Note that this is only a hint! The compiler can globally decide to *not* | |
216 | /// do this in order to speed up compilation. CGU-internal copies are | |
217 | /// only exist to enable inlining. If inlining is not performed (e.g. at | |
218 | /// `-Copt-level=0`) then the time for generating them is wasted and it's | |
219 | /// better to create a single copy with external linkage. | |
220 | pub fn generates_cgu_internal_copy(&self, tcx: TyCtxt<'tcx>) -> bool { | |
221 | if self.requires_inline(tcx) { | |
222 | return true; | |
ff7c6d11 | 223 | } |
74b04a01 XL |
224 | if let ty::InstanceDef::DropGlue(.., Some(ty)) = *self { |
225 | // Drop glue generally wants to be instantiated at every codegen | |
ff7c6d11 XL |
226 | // unit, but without an #[inline] hint. We should make this |
227 | // available to normal end-users. | |
74b04a01 XL |
228 | if tcx.sess.opts.incremental.is_none() { |
229 | return true; | |
230 | } | |
231 | // When compiling with incremental, we can generate a *lot* of | |
232 | // codegen units. Including drop glue into all of them has a | |
233 | // considerable compile time cost. | |
234 | // | |
235 | // We include enums without destructors to allow, say, optimizing | |
236 | // drops of `Option::None` before LTO. We also respect the intent of | |
237 | // `#[inline]` on `Drop::drop` implementations. | |
238 | return ty.ty_adt_def().map_or(true, |adt_def| { | |
cdc7bbd5 XL |
239 | adt_def.destructor(tcx).map_or_else( |
240 | || adt_def.is_enum(), | |
241 | |dtor| tcx.codegen_fn_attrs(dtor.did).requests_inline(), | |
242 | ) | |
74b04a01 | 243 | }); |
ff7c6d11 | 244 | } |
a1dfa0c6 | 245 | tcx.codegen_fn_attrs(self.def_id()).requests_inline() |
ff7c6d11 | 246 | } |
60c5eb7d XL |
247 | |
248 | pub fn requires_caller_location(&self, tcx: TyCtxt<'_>) -> bool { | |
dfeec247 | 249 | match *self { |
136023e0 XL |
250 | InstanceDef::Item(ty::WithOptConstParam { did: def_id, .. }) |
251 | | InstanceDef::Virtual(def_id, _) => { | |
04454e1e | 252 | tcx.body_codegen_attrs(def_id).flags.contains(CodegenFnAttrFlags::TRACK_CALLER) |
dfeec247 | 253 | } |
c295e0f8 | 254 | InstanceDef::ClosureOnceShim { call_once: _, track_caller } => track_caller, |
dfeec247 XL |
255 | _ => false, |
256 | } | |
60c5eb7d | 257 | } |
1b1a35ee XL |
258 | |
259 | /// Returns `true` when the MIR body associated with this instance should be monomorphized | |
260 | /// by its users (e.g. codegen or miri) by substituting the `substs` from `Instance` (see | |
261 | /// `Instance::substs_for_mir_body`). | |
262 | /// | |
263 | /// Otherwise, returns `false` only for some kinds of shims where the construction of the MIR | |
264 | /// body should perform necessary substitutions. | |
265 | pub fn has_polymorphic_mir_body(&self) -> bool { | |
266 | match *self { | |
267 | InstanceDef::CloneShim(..) | |
268 | | InstanceDef::FnPtrShim(..) | |
269 | | InstanceDef::DropGlue(_, Some(_)) => false, | |
270 | InstanceDef::ClosureOnceShim { .. } | |
271 | | InstanceDef::DropGlue(..) | |
272 | | InstanceDef::Item(_) | |
273 | | InstanceDef::Intrinsic(..) | |
274 | | InstanceDef::ReifyShim(..) | |
275 | | InstanceDef::Virtual(..) | |
064997fb | 276 | | InstanceDef::VTableShim(..) => true, |
1b1a35ee XL |
277 | } |
278 | } | |
cc61c64b XL |
279 | } |
280 | ||
281 | impl<'tcx> fmt::Display for Instance<'tcx> { | |
0bf4aa26 | 282 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
532ac7d7 | 283 | ty::tls::with(|tcx| { |
29967ef6 | 284 | let substs = tcx.lift(self.substs).expect("could not lift for printing"); |
5e7ed085 FG |
285 | let s = FmtPrinter::new(tcx, Namespace::ValueNS) |
286 | .print_def_path(self.def_id(), substs)? | |
287 | .into_buffer(); | |
288 | f.write_str(&s) | |
532ac7d7 XL |
289 | })?; |
290 | ||
cc61c64b XL |
291 | match self.def { |
292 | InstanceDef::Item(_) => Ok(()), | |
064997fb | 293 | InstanceDef::VTableShim(_) => write!(f, " - shim(vtable)"), |
dfeec247 XL |
294 | InstanceDef::ReifyShim(_) => write!(f, " - shim(reify)"), |
295 | InstanceDef::Intrinsic(_) => write!(f, " - intrinsic"), | |
296 | InstanceDef::Virtual(_, num) => write!(f, " - virtual#{}", num), | |
1b1a35ee | 297 | InstanceDef::FnPtrShim(_, ty) => write!(f, " - shim({})", ty), |
dfeec247 | 298 | InstanceDef::ClosureOnceShim { .. } => write!(f, " - shim"), |
1b1a35ee XL |
299 | InstanceDef::DropGlue(_, None) => write!(f, " - shim(None)"), |
300 | InstanceDef::DropGlue(_, Some(ty)) => write!(f, " - shim(Some({}))", ty), | |
301 | InstanceDef::CloneShim(_, ty) => write!(f, " - shim({})", ty), | |
cc61c64b XL |
302 | } |
303 | } | |
304 | } | |
305 | ||
dc9dc135 | 306 | impl<'tcx> Instance<'tcx> { |
dfeec247 XL |
307 | pub fn new(def_id: DefId, substs: SubstsRef<'tcx>) -> Instance<'tcx> { |
308 | assert!( | |
309 | !substs.has_escaping_bound_vars(), | |
310 | "substs of instance {:?} not normalized for codegen: {:?}", | |
311 | def_id, | |
312 | substs | |
313 | ); | |
3dfed10e | 314 | Instance { def: InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), substs } |
cc61c64b XL |
315 | } |
316 | ||
dc9dc135 | 317 | pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx> { |
29967ef6 XL |
318 | let substs = InternalSubsts::for_item(tcx, def_id, |param, _| match param.kind { |
319 | ty::GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(), | |
320 | ty::GenericParamDefKind::Type { .. } => { | |
321 | bug!("Instance::mono: {:?} has type parameters", def_id) | |
322 | } | |
323 | ty::GenericParamDefKind::Const { .. } => { | |
324 | bug!("Instance::mono: {:?} has const parameters", def_id) | |
325 | } | |
326 | }); | |
327 | ||
328 | Instance::new(def_id, substs) | |
cc61c64b XL |
329 | } |
330 | ||
331 | #[inline] | |
332 | pub fn def_id(&self) -> DefId { | |
333 | self.def.def_id() | |
334 | } | |
ea8adc8c | 335 | |
9fa01778 | 336 | /// Resolves a `(def_id, substs)` pair to an (optional) instance -- most commonly, |
ea8adc8c XL |
337 | /// this is used to find the precise code that will run for a trait method invocation, |
338 | /// if known. | |
339 | /// | |
f9f354fc | 340 | /// Returns `Ok(None)` if we cannot resolve `Instance` to a specific instance. |
ea8adc8c XL |
341 | /// For example, in a context like this, |
342 | /// | |
04454e1e | 343 | /// ```ignore (illustrative) |
ea8adc8c XL |
344 | /// fn foo<T: Debug>(t: T) { ... } |
345 | /// ``` | |
346 | /// | |
f9f354fc | 347 | /// trying to resolve `Debug::fmt` applied to `T` will yield `Ok(None)`, because we do not |
ea8adc8c XL |
348 | /// know what code ought to run. (Note that this setting is also affected by the |
349 | /// `RevealMode` in the parameter environment.) | |
350 | /// | |
351 | /// Presuming that coherence and type-check have succeeded, if this method is invoked | |
94b46f34 | 352 | /// in a monomorphic context (i.e., like during codegen), then it is guaranteed to return |
f9f354fc XL |
353 | /// `Ok(Some(instance))`. |
354 | /// | |
5e7ed085 | 355 | /// Returns `Err(ErrorGuaranteed)` when the `Instance` resolution process |
f9f354fc XL |
356 | /// couldn't complete due to errors elsewhere - this is distinct |
357 | /// from `Ok(None)` to avoid misleading diagnostics when an error | |
358 | /// has already been/will be emitted, for the original cause | |
dc9dc135 XL |
359 | pub fn resolve( |
360 | tcx: TyCtxt<'tcx>, | |
361 | param_env: ty::ParamEnv<'tcx>, | |
362 | def_id: DefId, | |
363 | substs: SubstsRef<'tcx>, | |
5e7ed085 | 364 | ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> { |
3dfed10e XL |
365 | Instance::resolve_opt_const_arg( |
366 | tcx, | |
367 | param_env, | |
368 | ty::WithOptConstParam::unknown(def_id), | |
369 | substs, | |
370 | ) | |
371 | } | |
372 | ||
373 | // This should be kept up to date with `resolve`. | |
374 | pub fn resolve_opt_const_arg( | |
375 | tcx: TyCtxt<'tcx>, | |
376 | param_env: ty::ParamEnv<'tcx>, | |
377 | def: ty::WithOptConstParam<DefId>, | |
378 | substs: SubstsRef<'tcx>, | |
5e7ed085 | 379 | ) -> Result<Option<Instance<'tcx>>, ErrorGuaranteed> { |
ba9703b0 XL |
380 | // All regions in the result of this query are erased, so it's |
381 | // fine to erase all of the input regions. | |
f9f354fc XL |
382 | |
383 | // HACK(eddyb) erase regions in `substs` first, so that `param_env.and(...)` | |
384 | // below is more likely to ignore the bounds in scope (e.g. if the only | |
385 | // generic parameters mentioned by `substs` were lifetime ones). | |
fc512014 | 386 | let substs = tcx.erase_regions(substs); |
f9f354fc XL |
387 | |
388 | // FIXME(eddyb) should this always use `param_env.with_reveal_all()`? | |
3dfed10e XL |
389 | if let Some((did, param_did)) = def.as_const_arg() { |
390 | tcx.resolve_instance_of_const_arg( | |
fc512014 | 391 | tcx.erase_regions(param_env.and((did, param_did, substs))), |
3dfed10e XL |
392 | ) |
393 | } else { | |
fc512014 | 394 | tcx.resolve_instance(tcx.erase_regions(param_env.and((def.did, substs)))) |
3dfed10e | 395 | } |
ea8adc8c | 396 | } |
ea8adc8c | 397 | |
e74abb32 XL |
398 | pub fn resolve_for_fn_ptr( |
399 | tcx: TyCtxt<'tcx>, | |
400 | param_env: ty::ParamEnv<'tcx>, | |
401 | def_id: DefId, | |
402 | substs: SubstsRef<'tcx>, | |
403 | ) -> Option<Instance<'tcx>> { | |
404 | debug!("resolve(def_id={:?}, substs={:?})", def_id, substs); | |
c295e0f8 XL |
405 | // Use either `resolve_closure` or `resolve_for_vtable` |
406 | assert!(!tcx.is_closure(def_id), "Called `resolve_for_fn_ptr` on closure: {:?}", def_id); | |
f9f354fc | 407 | Instance::resolve(tcx, param_env, def_id, substs).ok().flatten().map(|mut resolved| { |
e74abb32 | 408 | match resolved.def { |
3dfed10e | 409 | InstanceDef::Item(def) if resolved.def.requires_caller_location(tcx) => { |
e74abb32 | 410 | debug!(" => fn pointer created for function with #[track_caller]"); |
3dfed10e | 411 | resolved.def = InstanceDef::ReifyShim(def.did); |
60c5eb7d XL |
412 | } |
413 | InstanceDef::Virtual(def_id, _) => { | |
414 | debug!(" => fn pointer created for virtual call"); | |
415 | resolved.def = InstanceDef::ReifyShim(def_id); | |
416 | } | |
417 | _ => {} | |
e74abb32 | 418 | } |
60c5eb7d XL |
419 | |
420 | resolved | |
e74abb32 XL |
421 | }) |
422 | } | |
423 | ||
dc9dc135 XL |
424 | pub fn resolve_for_vtable( |
425 | tcx: TyCtxt<'tcx>, | |
426 | param_env: ty::ParamEnv<'tcx>, | |
427 | def_id: DefId, | |
428 | substs: SubstsRef<'tcx>, | |
429 | ) -> Option<Instance<'tcx>> { | |
136023e0 | 430 | debug!("resolve_for_vtable(def_id={:?}, substs={:?})", def_id, substs); |
a1dfa0c6 | 431 | let fn_sig = tcx.fn_sig(def_id); |
74b04a01 | 432 | let is_vtable_shim = !fn_sig.inputs().skip_binder().is_empty() |
e1599b0c XL |
433 | && fn_sig.input(0).skip_binder().is_param(0) |
434 | && tcx.generics_of(def_id).has_self; | |
a1dfa0c6 XL |
435 | if is_vtable_shim { |
436 | debug!(" => associated item with unsizeable self: Self"); | |
064997fb | 437 | Some(Instance { def: InstanceDef::VTableShim(def_id), substs }) |
a1dfa0c6 | 438 | } else { |
136023e0 XL |
439 | Instance::resolve(tcx, param_env, def_id, substs).ok().flatten().map(|mut resolved| { |
440 | match resolved.def { | |
441 | InstanceDef::Item(def) => { | |
442 | // We need to generate a shim when we cannot guarantee that | |
443 | // the caller of a trait object method will be aware of | |
444 | // `#[track_caller]` - this ensures that the caller | |
445 | // and callee ABI will always match. | |
446 | // | |
447 | // The shim is generated when all of these conditions are met: | |
448 | // | |
449 | // 1) The underlying method expects a caller location parameter | |
450 | // in the ABI | |
451 | if resolved.def.requires_caller_location(tcx) | |
452 | // 2) The caller location parameter comes from having `#[track_caller]` | |
453 | // on the implementation, and *not* on the trait method. | |
454 | && !tcx.should_inherit_track_caller(def.did) | |
455 | // If the method implementation comes from the trait definition itself | |
456 | // (e.g. `trait Foo { #[track_caller] my_fn() { /* impl */ } }`), | |
457 | // then we don't need to generate a shim. This check is needed because | |
458 | // `should_inherit_track_caller` returns `false` if our method | |
459 | // implementation comes from the trait block, and not an impl block | |
460 | && !matches!( | |
461 | tcx.opt_associated_item(def.did), | |
462 | Some(ty::AssocItem { | |
064997fb | 463 | container: ty::AssocItemContainer::TraitContainer, |
136023e0 XL |
464 | .. |
465 | }) | |
466 | ) | |
467 | { | |
c295e0f8 XL |
468 | if tcx.is_closure(def.did) { |
469 | debug!(" => vtable fn pointer created for closure with #[track_caller]: {:?} for method {:?} {:?}", | |
470 | def.did, def_id, substs); | |
471 | ||
472 | // Create a shim for the `FnOnce/FnMut/Fn` method we are calling | |
473 | // - unlike functions, invoking a closure always goes through a | |
474 | // trait. | |
475 | resolved = Instance { def: InstanceDef::ReifyShim(def_id), substs }; | |
476 | } else { | |
477 | debug!( | |
478 | " => vtable fn pointer created for function with #[track_caller]: {:?}", def.did | |
479 | ); | |
480 | resolved.def = InstanceDef::ReifyShim(def.did); | |
481 | } | |
136023e0 XL |
482 | } |
483 | } | |
484 | InstanceDef::Virtual(def_id, _) => { | |
485 | debug!(" => vtable fn pointer created for virtual call"); | |
486 | resolved.def = InstanceDef::ReifyShim(def_id); | |
487 | } | |
488 | _ => {} | |
489 | } | |
490 | ||
491 | resolved | |
492 | }) | |
a1dfa0c6 XL |
493 | } |
494 | } | |
495 | ||
ff7c6d11 | 496 | pub fn resolve_closure( |
dc9dc135 | 497 | tcx: TyCtxt<'tcx>, |
0bf4aa26 | 498 | def_id: DefId, |
e74abb32 | 499 | substs: ty::SubstsRef<'tcx>, |
dc9dc135 | 500 | requested_kind: ty::ClosureKind, |
064997fb | 501 | ) -> Option<Instance<'tcx>> { |
ba9703b0 | 502 | let actual_kind = substs.as_closure().kind(); |
ea8adc8c | 503 | |
ff7c6d11 | 504 | match needs_fn_once_adapter_shim(actual_kind, requested_kind) { |
dc9dc135 | 505 | Ok(true) => Instance::fn_once_adapter_instance(tcx, def_id, substs), |
064997fb | 506 | _ => Some(Instance::new(def_id, substs)), |
ff7c6d11 | 507 | } |
ea8adc8c | 508 | } |
a1dfa0c6 | 509 | |
dc9dc135 | 510 | pub fn resolve_drop_in_place(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> ty::Instance<'tcx> { |
3dfed10e | 511 | let def_id = tcx.require_lang_item(LangItem::DropInPlace, None); |
dc9dc135 | 512 | let substs = tcx.intern_substs(&[ty.into()]); |
f9f354fc | 513 | Instance::resolve(tcx, ty::ParamEnv::reveal_all(), def_id, substs).unwrap().unwrap() |
dc9dc135 XL |
514 | } |
515 | ||
516 | pub fn fn_once_adapter_instance( | |
517 | tcx: TyCtxt<'tcx>, | |
518 | closure_did: DefId, | |
e74abb32 | 519 | substs: ty::SubstsRef<'tcx>, |
064997fb | 520 | ) -> Option<Instance<'tcx>> { |
dfeec247 | 521 | debug!("fn_once_adapter_shim({:?}, {:?})", closure_did, substs); |
3dfed10e | 522 | let fn_once = tcx.require_lang_item(LangItem::FnOnce, None); |
dfeec247 XL |
523 | let call_once = tcx |
524 | .associated_items(fn_once) | |
74b04a01 | 525 | .in_definition_order() |
ba9703b0 | 526 | .find(|it| it.kind == ty::AssocKind::Fn) |
dfeec247 XL |
527 | .unwrap() |
528 | .def_id; | |
c295e0f8 XL |
529 | let track_caller = |
530 | tcx.codegen_fn_attrs(closure_did).flags.contains(CodegenFnAttrFlags::TRACK_CALLER); | |
531 | let def = ty::InstanceDef::ClosureOnceShim { call_once, track_caller }; | |
dc9dc135 XL |
532 | |
533 | let self_ty = tcx.mk_closure(closure_did, substs); | |
534 | ||
ba9703b0 | 535 | let sig = substs.as_closure().sig(); |
064997fb FG |
536 | let sig = |
537 | tcx.try_normalize_erasing_late_bound_regions(ty::ParamEnv::reveal_all(), sig).ok()?; | |
dc9dc135 XL |
538 | assert_eq!(sig.inputs().len(), 1); |
539 | let substs = tcx.mk_substs_trait(self_ty, &[sig.inputs()[0].into()]); | |
540 | ||
541 | debug!("fn_once_adapter_shim: self_ty={:?} sig={:?}", self_ty, sig); | |
064997fb | 542 | Some(Instance { def, substs }) |
dc9dc135 XL |
543 | } |
544 | ||
1b1a35ee | 545 | /// Depending on the kind of `InstanceDef`, the MIR body associated with an |
ba9703b0 XL |
546 | /// instance is expressed in terms of the generic parameters of `self.def_id()`, and in other |
547 | /// cases the MIR body is expressed in terms of the types found in the substitution array. | |
548 | /// In the former case, we want to substitute those generic types and replace them with the | |
549 | /// values from the substs when monomorphizing the function body. But in the latter case, we | |
550 | /// don't want to do that substitution, since it has already been done effectively. | |
551 | /// | |
1b1a35ee | 552 | /// This function returns `Some(substs)` in the former case and `None` otherwise -- i.e., if |
ba9703b0 | 553 | /// this function returns `None`, then the MIR body does not require substitution during |
1b1a35ee | 554 | /// codegen. |
29967ef6 | 555 | fn substs_for_mir_body(&self) -> Option<SubstsRef<'tcx>> { |
1b1a35ee | 556 | if self.def.has_polymorphic_mir_body() { Some(self.substs) } else { None } |
a1dfa0c6 | 557 | } |
3dfed10e | 558 | |
29967ef6 XL |
559 | pub fn subst_mir<T>(&self, tcx: TyCtxt<'tcx>, v: &T) -> T |
560 | where | |
561 | T: TypeFoldable<'tcx> + Copy, | |
562 | { | |
04454e1e FG |
563 | if let Some(substs) = self.substs_for_mir_body() { |
564 | EarlyBinder(*v).subst(tcx, substs) | |
565 | } else { | |
566 | *v | |
567 | } | |
29967ef6 XL |
568 | } |
569 | ||
cdc7bbd5 | 570 | #[inline(always)] |
29967ef6 XL |
571 | pub fn subst_mir_and_normalize_erasing_regions<T>( |
572 | &self, | |
573 | tcx: TyCtxt<'tcx>, | |
574 | param_env: ty::ParamEnv<'tcx>, | |
fc512014 | 575 | v: T, |
29967ef6 XL |
576 | ) -> T |
577 | where | |
578 | T: TypeFoldable<'tcx> + Clone, | |
579 | { | |
580 | if let Some(substs) = self.substs_for_mir_body() { | |
581 | tcx.subst_and_normalize_erasing_regions(substs, param_env, v) | |
582 | } else { | |
fc512014 | 583 | tcx.normalize_erasing_regions(param_env, v) |
29967ef6 XL |
584 | } |
585 | } | |
586 | ||
a2a8927a XL |
587 | #[inline(always)] |
588 | pub fn try_subst_mir_and_normalize_erasing_regions<T>( | |
589 | &self, | |
590 | tcx: TyCtxt<'tcx>, | |
591 | param_env: ty::ParamEnv<'tcx>, | |
592 | v: T, | |
593 | ) -> Result<T, NormalizationError<'tcx>> | |
594 | where | |
595 | T: TypeFoldable<'tcx> + Clone, | |
596 | { | |
597 | if let Some(substs) = self.substs_for_mir_body() { | |
598 | tcx.try_subst_and_normalize_erasing_regions(substs, param_env, v) | |
599 | } else { | |
600 | tcx.try_normalize_erasing_regions(param_env, v) | |
601 | } | |
602 | } | |
603 | ||
3dfed10e | 604 | /// Returns a new `Instance` where generic parameters in `instance.substs` are replaced by |
6a06907d | 605 | /// identity parameters if they are determined to be unused in `instance.def`. |
3dfed10e XL |
606 | pub fn polymorphize(self, tcx: TyCtxt<'tcx>) -> Self { |
607 | debug!("polymorphize: running polymorphization analysis"); | |
064997fb | 608 | if !tcx.sess.opts.unstable_opts.polymorphize { |
3dfed10e XL |
609 | return self; |
610 | } | |
611 | ||
c295e0f8 XL |
612 | let polymorphized_substs = polymorphize(tcx, self.def, self.substs); |
613 | debug!("polymorphize: self={:?} polymorphized_substs={:?}", self, polymorphized_substs); | |
614 | Self { def: self.def, substs: polymorphized_substs } | |
3dfed10e XL |
615 | } |
616 | } | |
617 | ||
618 | fn polymorphize<'tcx>( | |
619 | tcx: TyCtxt<'tcx>, | |
c295e0f8 | 620 | instance: ty::InstanceDef<'tcx>, |
3dfed10e XL |
621 | substs: SubstsRef<'tcx>, |
622 | ) -> SubstsRef<'tcx> { | |
c295e0f8 XL |
623 | debug!("polymorphize({:?}, {:?})", instance, substs); |
624 | let unused = tcx.unused_generic_params(instance); | |
3dfed10e XL |
625 | debug!("polymorphize: unused={:?}", unused); |
626 | ||
627 | // If this is a closure or generator then we need to handle the case where another closure | |
628 | // from the function is captured as an upvar and hasn't been polymorphized. In this case, | |
629 | // the unpolymorphized upvar closure would result in a polymorphized closure producing | |
630 | // multiple mono items (and eventually symbol clashes). | |
c295e0f8 | 631 | let def_id = instance.def_id(); |
3dfed10e XL |
632 | let upvars_ty = if tcx.is_closure(def_id) { |
633 | Some(substs.as_closure().tupled_upvars_ty()) | |
634 | } else if tcx.type_of(def_id).is_generator() { | |
635 | Some(substs.as_generator().tupled_upvars_ty()) | |
636 | } else { | |
637 | None | |
638 | }; | |
5e7ed085 | 639 | let has_upvars = upvars_ty.map_or(false, |ty| !ty.tuple_fields().is_empty()); |
3dfed10e XL |
640 | debug!("polymorphize: upvars_ty={:?} has_upvars={:?}", upvars_ty, has_upvars); |
641 | ||
642 | struct PolymorphizationFolder<'tcx> { | |
643 | tcx: TyCtxt<'tcx>, | |
fc512014 | 644 | } |
3dfed10e | 645 | |
a2a8927a | 646 | impl<'tcx> ty::TypeFolder<'tcx> for PolymorphizationFolder<'tcx> { |
3dfed10e XL |
647 | fn tcx<'a>(&'a self) -> TyCtxt<'tcx> { |
648 | self.tcx | |
649 | } | |
650 | ||
651 | fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> { | |
652 | debug!("fold_ty: ty={:?}", ty); | |
5099ac24 | 653 | match *ty.kind() { |
3dfed10e | 654 | ty::Closure(def_id, substs) => { |
c295e0f8 XL |
655 | let polymorphized_substs = polymorphize( |
656 | self.tcx, | |
657 | ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), | |
658 | substs, | |
659 | ); | |
3dfed10e XL |
660 | if substs == polymorphized_substs { |
661 | ty | |
662 | } else { | |
663 | self.tcx.mk_closure(def_id, polymorphized_substs) | |
664 | } | |
665 | } | |
666 | ty::Generator(def_id, substs, movability) => { | |
c295e0f8 XL |
667 | let polymorphized_substs = polymorphize( |
668 | self.tcx, | |
669 | ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)), | |
670 | substs, | |
671 | ); | |
3dfed10e XL |
672 | if substs == polymorphized_substs { |
673 | ty | |
674 | } else { | |
675 | self.tcx.mk_generator(def_id, polymorphized_substs, movability) | |
676 | } | |
677 | } | |
678 | _ => ty.super_fold_with(self), | |
679 | } | |
680 | } | |
681 | } | |
682 | ||
683 | InternalSubsts::for_item(tcx, def_id, |param, _| { | |
684 | let is_unused = unused.contains(param.index).unwrap_or(false); | |
685 | debug!("polymorphize: param={:?} is_unused={:?}", param, is_unused); | |
686 | match param.kind { | |
687 | // Upvar case: If parameter is a type parameter.. | |
688 | ty::GenericParamDefKind::Type { .. } if | |
689 | // ..and has upvars.. | |
690 | has_upvars && | |
691 | // ..and this param has the same type as the tupled upvars.. | |
692 | upvars_ty == Some(substs[param.index as usize].expect_ty()) => { | |
693 | // ..then double-check that polymorphization marked it used.. | |
694 | debug_assert!(!is_unused); | |
695 | // ..and polymorphize any closures/generators captured as upvars. | |
696 | let upvars_ty = upvars_ty.unwrap(); | |
697 | let polymorphized_upvars_ty = upvars_ty.fold_with( | |
698 | &mut PolymorphizationFolder { tcx }); | |
699 | debug!("polymorphize: polymorphized_upvars_ty={:?}", polymorphized_upvars_ty); | |
700 | ty::GenericArg::from(polymorphized_upvars_ty) | |
701 | }, | |
702 | ||
703 | // Simple case: If parameter is a const or type parameter.. | |
cdc7bbd5 | 704 | ty::GenericParamDefKind::Const { .. } | ty::GenericParamDefKind::Type { .. } if |
3dfed10e XL |
705 | // ..and is within range and unused.. |
706 | unused.contains(param.index).unwrap_or(false) => | |
707 | // ..then use the identity for this parameter. | |
708 | tcx.mk_param_from_def(param), | |
709 | ||
710 | // Otherwise, use the parameter as before. | |
711 | _ => substs[param.index as usize], | |
712 | } | |
713 | }) | |
ea8adc8c XL |
714 | } |
715 | ||
dc9dc135 XL |
716 | fn needs_fn_once_adapter_shim( |
717 | actual_closure_kind: ty::ClosureKind, | |
718 | trait_closure_kind: ty::ClosureKind, | |
719 | ) -> Result<bool, ()> { | |
ea8adc8c | 720 | match (actual_closure_kind, trait_closure_kind) { |
dfeec247 XL |
721 | (ty::ClosureKind::Fn, ty::ClosureKind::Fn) |
722 | | (ty::ClosureKind::FnMut, ty::ClosureKind::FnMut) | |
723 | | (ty::ClosureKind::FnOnce, ty::ClosureKind::FnOnce) => { | |
724 | // No adapter needed. | |
725 | Ok(false) | |
726 | } | |
ea8adc8c XL |
727 | (ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => { |
728 | // The closure fn `llfn` is a `fn(&self, ...)`. We want a | |
94b46f34 | 729 | // `fn(&mut self, ...)`. In fact, at codegen time, these are |
ea8adc8c XL |
730 | // basically the same thing, so we can just return llfn. |
731 | Ok(false) | |
732 | } | |
ba9703b0 | 733 | (ty::ClosureKind::Fn | ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => { |
dfeec247 XL |
734 | // The closure fn `llfn` is a `fn(&self, ...)` or `fn(&mut |
735 | // self, ...)`. We want a `fn(self, ...)`. We can produce | |
736 | // this by doing something like: | |
737 | // | |
738 | // fn call_once(self, ...) { call_mut(&self, ...) } | |
739 | // fn call_once(mut self, ...) { call_mut(&mut self, ...) } | |
740 | // | |
741 | // These are both the same at codegen time. | |
742 | Ok(true) | |
ea8adc8c | 743 | } |
ba9703b0 | 744 | (ty::ClosureKind::FnMut | ty::ClosureKind::FnOnce, _) => Err(()), |
ea8adc8c XL |
745 | } |
746 | } |