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// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use rustc::hir::def_id::DefId;
use rustc::middle::lang_items::DropInPlaceFnLangItem;
use rustc::traits;
use rustc::ty::adjustment::CustomCoerceUnsized;
use rustc::ty::subst::Kind;
use rustc::ty::{self, Ty, TyCtxt};
pub use rustc::ty::Instance;
pub use self::item::{MonoItem, MonoItemExt};
pub mod collector;
pub mod item;
pub mod partitioning;
fn fn_once_adapter_instance<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
closure_did: DefId,
substs: ty::ClosureSubsts<'tcx>,
) -> Instance<'tcx> {
debug!("fn_once_adapter_shim({:?}, {:?})",
closure_did,
substs);
let fn_once = tcx.lang_items().fn_once_trait().unwrap();
let call_once = tcx.associated_items(fn_once)
.find(|it| it.kind == ty::AssociatedKind::Method)
.unwrap().def_id;
let def = ty::InstanceDef::ClosureOnceShim { call_once };
let self_ty = tcx.mk_closure_from_closure_substs(
closure_did, substs);
let sig = substs.closure_sig(closure_did, tcx);
let sig = tcx.erase_late_bound_regions_and_normalize(&sig);
assert_eq!(sig.inputs().len(), 1);
let substs = tcx.mk_substs([
Kind::from(self_ty),
Kind::from(sig.inputs()[0]),
].iter().cloned());
debug!("fn_once_adapter_shim: self_ty={:?} sig={:?}", self_ty, sig);
Instance { def, substs }
}
fn needs_fn_once_adapter_shim(actual_closure_kind: ty::ClosureKind,
trait_closure_kind: ty::ClosureKind)
-> Result<bool, ()>
{
match (actual_closure_kind, trait_closure_kind) {
(ty::ClosureKind::Fn, ty::ClosureKind::Fn) |
(ty::ClosureKind::FnMut, ty::ClosureKind::FnMut) |
(ty::ClosureKind::FnOnce, ty::ClosureKind::FnOnce) => {
// No adapter needed.
Ok(false)
}
(ty::ClosureKind::Fn, ty::ClosureKind::FnMut) => {
// The closure fn `llfn` is a `fn(&self, ...)`. We want a
// `fn(&mut self, ...)`. In fact, at trans time, these are
// basically the same thing, so we can just return llfn.
Ok(false)
}
(ty::ClosureKind::Fn, ty::ClosureKind::FnOnce) |
(ty::ClosureKind::FnMut, ty::ClosureKind::FnOnce) => {
// The closure fn `llfn` is a `fn(&self, ...)` or `fn(&mut
// self, ...)`. We want a `fn(self, ...)`. We can produce
// this by doing something like:
//
// fn call_once(self, ...) { call_mut(&self, ...) }
// fn call_once(mut self, ...) { call_mut(&mut self, ...) }
//
// These are both the same at trans time.
Ok(true)
}
_ => Err(()),
}
}
pub fn resolve_closure<'a, 'tcx> (
tcx: TyCtxt<'a, 'tcx, 'tcx>,
def_id: DefId,
substs: ty::ClosureSubsts<'tcx>,
requested_kind: ty::ClosureKind)
-> Instance<'tcx>
{
let actual_kind = substs.closure_kind(def_id, tcx);
match needs_fn_once_adapter_shim(actual_kind, requested_kind) {
Ok(true) => fn_once_adapter_instance(tcx, def_id, substs),
_ => Instance::new(def_id, substs.substs)
}
}
pub fn resolve_drop_in_place<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
ty: Ty<'tcx>)
-> ty::Instance<'tcx>
{
let def_id = tcx.require_lang_item(DropInPlaceFnLangItem);
let substs = tcx.intern_substs(&[Kind::from(ty)]);
Instance::resolve(tcx, ty::ParamEnv::empty(traits::Reveal::All), def_id, substs).unwrap()
}
pub fn custom_coerce_unsize_info<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
source_ty: Ty<'tcx>,
target_ty: Ty<'tcx>)
-> CustomCoerceUnsized {
let def_id = tcx.lang_items().coerce_unsized_trait().unwrap();
let trait_ref = ty::Binder(ty::TraitRef {
def_id: def_id,
substs: tcx.mk_substs_trait(source_ty, &[target_ty])
});
match tcx.trans_fulfill_obligation( (ty::ParamEnv::empty(traits::Reveal::All), trait_ref)) {
traits::VtableImpl(traits::VtableImplData { impl_def_id, .. }) => {
tcx.coerce_unsized_info(impl_def_id).custom_kind.unwrap()
}
vtable => {
bug!("invalid CoerceUnsized vtable: {:?}", vtable);
}
}
}
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