bjoernager/rust
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Reuse more rustc code instead of copying it into miri

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This commit is contained in:
Oliver Schneider 2017-03-23 13:35:19 +01:00
parent 0255a51468
commit 70ea218d2b
1 changed files with 12 additions and 219 deletions
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231
src/traits.rs
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@ -1,12 +1,11 @@
use rustc::traits::{self, Reveal, SelectionContext};
use rustc::traits::{self, Reveal};
use eval_context::EvalContext;
use memory::Pointer;
use rustc::hir::def_id::DefId;
use rustc::ty::fold::TypeFoldable;
use rustc::ty::subst::Substs;
use rustc::ty::{self, Ty, TyCtxt};
use rustc::ty::{self, Ty};
use syntax::codemap::DUMMY_SP;
use syntax::ast;
@ -43,101 +42,27 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
/// making an object `Foo<Trait>` from a value of type `Foo<T>`, then
/// `trait_ref` would map `T:Trait`.
pub fn get_vtable(&mut self, ty: Ty<'tcx>, trait_ref: ty::PolyTraitRef<'tcx>) -> EvalResult<'tcx, Pointer> {
let tcx = self.tcx;
debug!("get_vtable(trait_ref={:?})", trait_ref);
let methods: Vec<_> = traits::supertraits(tcx, trait_ref).flat_map(|trait_ref| {
match self.fulfill_obligation(trait_ref) {
// Should default trait error here?
traits::VtableDefaultImpl(_) |
traits::VtableBuiltin(_) => {
Vec::new().into_iter()
}
traits::VtableImpl(traits::VtableImplData { impl_def_id: id, substs, .. }) => {
self.get_vtable_methods(id, substs)
.into_iter()
.map(|opt_mth| opt_mth.map(|mth| {
self.memory.create_fn_ptr(mth.method.def_id, mth.substs)
}))
.collect::<Vec<_>>()
.into_iter()
}
traits::VtableClosure(
traits::VtableClosureData {
closure_def_id,
substs,
..
}
) => {
let instance = ::eval_context::resolve_closure(self.tcx, closure_def_id, substs, ty::ClosureKind::FnOnce);
vec![Some(self.memory.create_fn_alloc(instance))].into_iter()
}
// turn a function definition into a Fn trait object
traits::VtableFnPointer(traits::VtableFnPointerData { fn_ty, .. }) => {
match fn_ty.sty {
ty::TyFnDef(did, substs, _) => {
let instance = ty::Instance {
def: ty::InstanceDef::FnPtrShim(did, fn_ty),
substs,
};
vec![Some(self.memory.create_fn_alloc(instance))].into_iter()
},
ty::TyFnPtr(_) => {
unimplemented!();
},
_ => bug!("bad VtableFnPointer fn_ty: {:#?}", fn_ty.sty),
}
}
traits::VtableObject(ref data) => {
// this would imply that the Self type being erased is
// an object type; this cannot happen because we
// cannot cast an unsized type into a trait object
bug!("cannot get vtable for an object type: {:?}",
data);
}
vtable @ traits::VtableParam(..) => {
bug!("resolved vtable for {:?} to bad vtable {:?} in trans",
trait_ref,
vtable);
}
}
}).collect();
let size = self.type_size(trait_ref.self_ty())?.expect("can't create a vtable for an unsized type");
let align = self.type_align(trait_ref.self_ty())?;
let ptr_size = self.memory.pointer_size();
let vtable = self.memory.allocate(ptr_size * (3 + methods.len() as u64), ptr_size)?;
let methods = ::rustc::traits::get_vtable_methods(self.tcx, trait_ref);
let vtable = self.memory.allocate(ptr_size * (3 + methods.count() as u64), ptr_size)?;
// in case there is no drop function to be called, this still needs to be initialized
self.memory.write_usize(vtable, 0)?;
let drop_in_place = self.tcx.lang_items.drop_in_place_fn().expect("drop_in_place lang item not available");
if let ty::TyAdt(adt_def, substs) = trait_ref.self_ty().sty {
if adt_def.has_dtor(self.tcx) {
let env = self.tcx.empty_parameter_environment();
let def = if self.tcx.type_needs_drop_given_env(ty, &env) {
ty::InstanceDef::DropGlue(drop_in_place, Some(ty))
} else {
ty::InstanceDef::DropGlue(drop_in_place, None)
};
let instance = ty::Instance { substs, def };
let fn_ptr = self.memory.create_fn_alloc(instance);
self.memory.write_ptr(vtable, fn_ptr)?;
}
}
let drop = ::eval_context::resolve_drop_in_place(self.tcx, ty);
let drop = self.memory.create_fn_alloc(drop);
self.memory.write_ptr(vtable, drop)?;
self.memory.write_usize(vtable.offset(ptr_size), size)?;
self.memory.write_usize(vtable.offset(ptr_size * 2), align)?;
for (i, method) in methods.into_iter().enumerate() {
if let Some(method) = method {
self.memory.write_ptr(vtable.offset(ptr_size * (3 + i as u64)), method)?;
for (i, method) in ::rustc::traits::get_vtable_methods(self.tcx, trait_ref).enumerate() {
if let Some((def_id, substs)) = method {
let instance = ::eval_context::resolve(self.tcx, def_id, substs);
let fn_ptr = self.memory.create_fn_alloc(instance);
self.memory.write_ptr(vtable.offset(ptr_size * (3 + i as u64)), fn_ptr)?;
}
}
@ -167,94 +92,6 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
Ok((size, align))
}
fn get_vtable_methods(&mut self, impl_id: DefId, substs: &'tcx Substs<'tcx>) -> Vec<Option<ImplMethod<'tcx>>> {
debug!("get_vtable_methods(impl_id={:?}, substs={:?}", impl_id, substs);
let trait_id = match self.tcx.impl_trait_ref(impl_id) {
Some(t_id) => t_id.def_id,
None => bug!("make_impl_vtable: don't know how to \
make a vtable for a type impl!")
};
self.tcx.populate_implementations_for_trait_if_necessary(trait_id);
self.tcx
.associated_items(trait_id)
// Filter out non-method items.
.filter_map(|trait_method_type| {
if trait_method_type.kind != ty::AssociatedKind::Method {
return None;
}
debug!("get_vtable_methods: trait_method_type={:?}",
trait_method_type);
let name = trait_method_type.name;
// Some methods cannot be called on an object; skip those.
if !self.tcx.is_vtable_safe_method(trait_id, &trait_method_type) {
debug!("get_vtable_methods: not vtable safe");
return Some(None);
}
debug!("get_vtable_methods: trait_method_type={:?}",
trait_method_type);
// the method may have some early-bound lifetimes, add
// regions for those
let method_substs = Substs::for_item(self.tcx, trait_method_type.def_id,
|_, _| self.tcx.mk_region(ty::ReErased),
|_, _| self.tcx.types.err);
// The substitutions we have are on the impl, so we grab
// the method type from the impl to substitute into.
let mth = get_impl_method(self.tcx, method_substs, impl_id, substs, name);
debug!("get_vtable_methods: mth={:?}", mth);
// If this is a default method, it's possible that it
// relies on where clauses that do not hold for this
// particular set of type parameters. Note that this
// method could then never be called, so we do not want to
// try and trans it, in that case. Issue #23435.
if mth.is_provided {
let predicates = self.tcx.item_predicates(trait_method_type.def_id).instantiate_own(self.tcx, mth.substs);
if !self.normalize_and_test_predicates(predicates.predicates) {
debug!("get_vtable_methods: predicates do not hold");
return Some(None);
}
}
Some(Some(mth))
})
.collect()
}
/// Normalizes the predicates and checks whether they hold. If this
/// returns false, then either normalize encountered an error or one
/// of the predicates did not hold. Used when creating vtables to
/// check for unsatisfiable methods.
fn normalize_and_test_predicates(&mut self, predicates: Vec<ty::Predicate<'tcx>>) -> bool {
debug!("normalize_and_test_predicates(predicates={:?})",
predicates);
self.tcx.infer_ctxt((), Reveal::All).enter(|infcx| {
let mut selcx = SelectionContext::new(&infcx);
let mut fulfill_cx = traits::FulfillmentContext::new();
let cause = traits::ObligationCause::dummy();
let traits::Normalized { value: predicates, obligations } =
traits::normalize(&mut selcx, cause.clone(), &predicates);
for obligation in obligations {
fulfill_cx.register_predicate_obligation(&infcx, obligation);
}
for predicate in predicates {
let obligation = traits::Obligation::new(cause.clone(), predicate);
fulfill_cx.register_predicate_obligation(&infcx, obligation);
}
fulfill_cx.select_all_or_error(&infcx).is_ok()
})
}
pub(crate) fn resolve_associated_const(
&self,
def_id: DefId,
@ -275,47 +112,3 @@ impl<'a, 'tcx> EvalContext<'a, 'tcx> {
ty::Instance::new(def_id, substs)
}
}
#[derive(Debug)]
pub(super) struct ImplMethod<'tcx> {
pub(super) method: ty::AssociatedItem,
pub(super) substs: &'tcx Substs<'tcx>,
pub(super) is_provided: bool,
}
/// Locates the applicable definition of a method, given its name.
pub(super) fn get_impl_method<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
substs: &'tcx Substs<'tcx>,
impl_def_id: DefId,
impl_substs: &'tcx Substs<'tcx>,
name: ast::Name,
) -> ImplMethod<'tcx> {
assert!(!substs.needs_infer());
let trait_def_id = tcx.trait_id_of_impl(impl_def_id).unwrap();
let trait_def = tcx.lookup_trait_def(trait_def_id);
match trait_def.ancestors(impl_def_id).defs(tcx, name, ty::AssociatedKind::Method).next() {
Some(node_item) => {
let substs = tcx.infer_ctxt((), Reveal::All).enter(|infcx| {
let substs = substs.rebase_onto(tcx, trait_def_id, impl_substs);
let substs = traits::translate_substs(&infcx, impl_def_id,
substs, node_item.node);
tcx.lift(&substs).unwrap_or_else(|| {
bug!("trans::meth::get_impl_method: translate_substs \
returned {:?} which contains inference types/regions",
substs);
})
});
ImplMethod {
method: node_item.item,
substs,
is_provided: node_item.node.is_from_trait(),
}
}
None => {
bug!("method {:?} not found in {:?}", name, impl_def_id)
}
}
}