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avoid translating roots with predicates that do not hold

Fixes #37725.
This commit is contained in:
Ariel Ben-Yehuda 2017-06-21 14:50:43 +03:00
parent 1143eb26a2
commit 3ac976861d
4 changed files with 41 additions and 12 deletions

View file

@ -597,7 +597,7 @@ pub fn normalize_and_test_predicates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
debug!("normalize_and_test_predicates(predicates={:?})", debug!("normalize_and_test_predicates(predicates={:?})",
predicates); predicates);
tcx.infer_ctxt().enter(|infcx| { let result = tcx.infer_ctxt().enter(|infcx| {
let param_env = ty::ParamEnv::empty(Reveal::All); let param_env = ty::ParamEnv::empty(Reveal::All);
let mut selcx = SelectionContext::new(&infcx); let mut selcx = SelectionContext::new(&infcx);
let mut fulfill_cx = FulfillmentContext::new(); let mut fulfill_cx = FulfillmentContext::new();
@ -613,7 +613,10 @@ pub fn normalize_and_test_predicates<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
} }
fulfill_cx.select_all_or_error(&infcx).is_ok() fulfill_cx.select_all_or_error(&infcx).is_ok()
}) });
debug!("normalize_and_test_predicates(predicates={:?}) = {:?}",
predicates, result);
result
} }
/// Given a trait `trait_ref`, iterates the vtable entries /// Given a trait `trait_ref`, iterates the vtable entries

View file

@ -195,7 +195,7 @@ use rustc::hir::map as hir_map;
use rustc::hir::def_id::DefId; use rustc::hir::def_id::DefId;
use rustc::middle::lang_items::{ExchangeMallocFnLangItem}; use rustc::middle::lang_items::{ExchangeMallocFnLangItem};
use rustc::traits; use rustc::traits;
use rustc::ty::subst::{Substs, Subst}; use rustc::ty::subst::Substs;
use rustc::ty::{self, TypeFoldable, TyCtxt}; use rustc::ty::{self, TypeFoldable, TyCtxt};
use rustc::ty::adjustment::CustomCoerceUnsized; use rustc::ty::adjustment::CustomCoerceUnsized;
use rustc::mir::{self, Location}; use rustc::mir::{self, Location};
@ -304,6 +304,7 @@ fn collect_roots<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>,
scx.tcx().hir.krate().visit_all_item_likes(&mut visitor); scx.tcx().hir.krate().visit_all_item_likes(&mut visitor);
} }
roots.retain(|root| root.is_instantiable(scx.tcx()));
roots roots
} }
@ -937,14 +938,9 @@ fn create_trans_items_for_default_impls<'a, 'tcx>(scx: &SharedCrateContext<'a, '
let instance = let instance =
monomorphize::resolve(scx, method.def_id, callee_substs); monomorphize::resolve(scx, method.def_id, callee_substs);
let predicates = tcx.predicates_of(instance.def_id()).predicates let trans_item = create_fn_trans_item(instance);
.subst(tcx, instance.substs); if trans_item.is_instantiable(tcx) && should_trans_locally(tcx, &instance) {
if !traits::normalize_and_test_predicates(tcx, predicates) { output.push(trans_item);
continue;
}
if should_trans_locally(tcx, &instance) {
output.push(create_fn_trans_item(instance));
} }
} }
} }

View file

@ -25,8 +25,9 @@ use llvm;
use monomorphize::Instance; use monomorphize::Instance;
use rustc::hir; use rustc::hir;
use rustc::hir::def_id::DefId; use rustc::hir::def_id::DefId;
use rustc::traits;
use rustc::ty::{self, Ty, TyCtxt, TypeFoldable}; use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
use rustc::ty::subst::Substs; use rustc::ty::subst::{Subst, Substs};
use syntax::ast::{self, NodeId}; use syntax::ast::{self, NodeId};
use syntax::attr; use syntax::attr;
use syntax_pos::Span; use syntax_pos::Span;
@ -250,6 +251,21 @@ impl<'a, 'tcx> TransItem<'tcx> {
} }
} }
/// Returns whether this instance is instantiable - whether it has no unsatisfied
/// predicates.
pub fn is_instantiable(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> bool {
debug!("is_instantiable({:?})", self);
let (def_id, substs) = match *self {
TransItem::Fn(ref instance) => (instance.def_id(), instance.substs),
TransItem::Static(node_id) => (tcx.hir.local_def_id(node_id), Substs::empty()),
// global asm never has predicates
TransItem::GlobalAsm(..) => return true
};
let predicates = tcx.predicates_of(def_id).predicates.subst(tcx, substs);
traits::normalize_and_test_predicates(tcx, predicates)
}
pub fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String { pub fn to_string(&self, tcx: TyCtxt<'a, 'tcx, 'tcx>) -> String {
let hir_map = &tcx.hir; let hir_map = &tcx.hir;

View file

@ -0,0 +1,14 @@
// Copyright 2016 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.
pub fn foo<'a>(s: &'a mut ()) where &'a mut (): Clone {
s.clone();
}
fn main() {}