1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
15 use rustc::hir::def_id::DefId;
16 use rustc::middle::lang_items::DropInPlaceFnLangItem;
18 use rustc::ty::adjustment::CustomCoerceUnsized;
19 use rustc::ty::subst::{Kind, Subst, Substs};
20 use rustc::ty::{self, Ty, TyCtxt};
22 use syntax::codemap::DUMMY_SP;
24 pub use rustc::ty::Instance;
26 fn fn_once_adapter_instance<'a, 'tcx>(
27 tcx: TyCtxt<'a, 'tcx, 'tcx>,
29 substs: ty::ClosureSubsts<'tcx>,
31 debug!("fn_once_adapter_shim({:?}, {:?})",
34 let fn_once = tcx.lang_items.fn_once_trait().unwrap();
35 let call_once = tcx.associated_items(fn_once)
36 .find(|it| it.kind == ty::AssociatedKind::Method)
38 let def = ty::InstanceDef::ClosureOnceShim { call_once };
40 let self_ty = tcx.mk_closure_from_closure_substs(
43 let sig = tcx.closure_type(closure_did).subst(tcx, substs.substs);
44 let sig = tcx.erase_late_bound_regions_and_normalize(&sig);
45 assert_eq!(sig.inputs().len(), 1);
46 let substs = tcx.mk_substs([
48 Kind::from(sig.inputs()[0]),
51 debug!("fn_once_adapter_shim: self_ty={:?} sig={:?}", self_ty, sig);
52 Instance { def, substs }
55 fn needs_fn_once_adapter_shim(actual_closure_kind: ty::ClosureKind,
56 trait_closure_kind: ty::ClosureKind)
59 match (actual_closure_kind, trait_closure_kind) {
60 (ty::ClosureKind::Fn, ty::ClosureKind::Fn) |
61 (ty::ClosureKind::FnMut, ty::ClosureKind::FnMut) |
62 (ty::ClosureKind::FnOnce, ty::ClosureKind::FnOnce) => {
66 (ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => {
67 // The closure fn `llfn` is a `fn(&self, ...)`. We want a
68 // `fn(&mut self, ...)`. In fact, at trans time, these are
69 // basically the same thing, so we can just return llfn.
72 (ty::ClosureKind::Fn, ty::ClosureKind::FnOnce) |
73 (ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => {
74 // The closure fn `llfn` is a `fn(&self, ...)` or `fn(&mut
75 // self, ...)`. We want a `fn(self, ...)`. We can produce
76 // this by doing something like:
78 // fn call_once(self, ...) { call_mut(&self, ...) }
79 // fn call_once(mut self, ...) { call_mut(&mut self, ...) }
81 // These are both the same at trans time.
88 pub fn resolve_closure<'a, 'tcx> (
89 scx: &SharedCrateContext<'a, 'tcx>,
91 substs: ty::ClosureSubsts<'tcx>,
92 requested_kind: ty::ClosureKind)
95 let actual_kind = scx.tcx().closure_kind(def_id);
97 match needs_fn_once_adapter_shim(actual_kind, requested_kind) {
98 Ok(true) => fn_once_adapter_instance(scx.tcx(), def_id, substs),
99 _ => Instance::new(def_id, substs.substs)
103 fn resolve_associated_item<'a, 'tcx>(
104 scx: &SharedCrateContext<'a, 'tcx>,
105 trait_item: &ty::AssociatedItem,
107 rcvr_substs: &'tcx Substs<'tcx>
108 ) -> Instance<'tcx> {
110 let def_id = trait_item.def_id;
111 debug!("resolve_associated_item(trait_item={:?}, \
114 def_id, trait_id, rcvr_substs);
116 let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs);
117 let vtbl = tcx.trans_fulfill_obligation(DUMMY_SP, ty::Binder(trait_ref));
119 // Now that we know which impl is being used, we can dispatch to
120 // the actual function:
122 traits::VtableImpl(impl_data) => {
123 let (def_id, substs) = traits::find_associated_item(
124 tcx, trait_item, rcvr_substs, &impl_data);
125 let substs = tcx.erase_regions(&substs);
126 ty::Instance::new(def_id, substs)
128 traits::VtableClosure(closure_data) => {
129 let trait_closure_kind = tcx.lang_items.fn_trait_kind(trait_id).unwrap();
130 resolve_closure(scx, closure_data.closure_def_id, closure_data.substs,
133 traits::VtableFnPointer(ref data) => {
135 def: ty::InstanceDef::FnPtrShim(trait_item.def_id, data.fn_ty),
139 traits::VtableObject(ref data) => {
140 let index = tcx.get_vtable_index_of_object_method(data, def_id);
142 def: ty::InstanceDef::Virtual(def_id, index),
147 bug!("static call to invalid vtable: {:?}", vtbl)
152 /// The point where linking happens. Resolve a (def_id, substs)
153 /// pair to an instance.
154 pub fn resolve<'a, 'tcx>(
155 scx: &SharedCrateContext<'a, 'tcx>,
157 substs: &'tcx Substs<'tcx>
158 ) -> Instance<'tcx> {
159 debug!("resolve(def_id={:?}, substs={:?})",
161 let result = if let Some(trait_def_id) = scx.tcx().trait_of_item(def_id) {
162 debug!(" => associated item, attempting to find impl");
163 let item = scx.tcx().associated_item(def_id);
164 resolve_associated_item(scx, &item, trait_def_id, substs)
166 let item_type = def_ty(scx, def_id, substs);
167 let def = match item_type.sty {
168 ty::TyFnDef(_, _, f) if
169 f.abi() == Abi::RustIntrinsic ||
170 f.abi() == Abi::PlatformIntrinsic =>
172 debug!(" => intrinsic");
173 ty::InstanceDef::Intrinsic(def_id)
176 if Some(def_id) == scx.tcx().lang_items.drop_in_place_fn() {
177 let ty = substs.type_at(0);
178 if glue::needs_drop_glue(scx, ty) {
179 debug!(" => nontrivial drop glue");
180 ty::InstanceDef::DropGlue(def_id, Some(ty))
182 debug!(" => trivial drop glue");
183 ty::InstanceDef::DropGlue(def_id, None)
186 debug!(" => free item");
187 ty::InstanceDef::Item(def_id)
191 Instance { def, substs }
193 debug!("resolve(def_id={:?}, substs={:?}) = {}",
194 def_id, substs, result);
198 pub fn resolve_drop_in_place<'a, 'tcx>(
199 scx: &SharedCrateContext<'a, 'tcx>,
201 -> ty::Instance<'tcx>
203 let def_id = scx.tcx().require_lang_item(DropInPlaceFnLangItem);
204 let substs = scx.tcx().intern_substs(&[Kind::from(ty)]);
205 resolve(scx, def_id, substs)
208 pub fn custom_coerce_unsize_info<'scx, 'tcx>(scx: &SharedCrateContext<'scx, 'tcx>,
211 -> CustomCoerceUnsized {
212 let trait_ref = ty::Binder(ty::TraitRef {
213 def_id: scx.tcx().lang_items.coerce_unsized_trait().unwrap(),
214 substs: scx.tcx().mk_substs_trait(source_ty, &[target_ty])
217 match scx.tcx().trans_fulfill_obligation(DUMMY_SP, trait_ref) {
218 traits::VtableImpl(traits::VtableImplData { impl_def_id, .. }) => {
219 scx.tcx().coerce_unsized_info(impl_def_id).custom_kind.unwrap()
222 bug!("invalid CoerceUnsized vtable: {:?}", vtable);
227 /// Returns the normalized type of a struct field
228 pub fn field_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
229 param_substs: &Substs<'tcx>,
230 f: &'tcx ty::FieldDef)
233 tcx.normalize_associated_type(&f.ty(tcx, param_substs))