diff options
| -rw-r--r-- | src/librustc/traits/trans/mod.rs | 147 | ||||
| -rw-r--r-- | src/librustc_trans/collector.rs | 28 | ||||
| -rw-r--r-- | src/librustc_trans/common.rs | 4 | ||||
| -rw-r--r-- | src/librustc_trans/mir/constant.rs | 4 | ||||
| -rw-r--r-- | src/librustc_trans/mir/mod.rs | 7 | ||||
| -rw-r--r-- | src/librustc_trans/monomorphize.rs | 128 |
6 files changed, 164 insertions, 154 deletions
diff --git a/src/librustc/traits/trans/mod.rs b/src/librustc/traits/trans/mod.rs index 8517f573e60..e38306aed2a 100644 --- a/src/librustc/traits/trans/mod.rs +++ b/src/librustc/traits/trans/mod.rs @@ -1,15 +1,154 @@ +// 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. + +// This file contains various trait resolution methods used by trans. +// They all assume regions can be erased and monomorphic types. It +// seems likely that they should eventually be merged into more +// general routines. + use dep_graph::{DepGraph, DepNode, DepTrackingMap, DepTrackingMapConfig}; use hir::def_id::DefId; +use infer::TransNormalize; use std::cell::RefCell; use std::marker::PhantomData; -use traits::Vtable; -use ty::{self, Ty}; +use syntax::ast; +use syntax_pos::Span; +use traits::{FulfillmentContext, Obligation, ObligationCause, Reveal, SelectionContext, Vtable}; +use ty::{self, Ty, TyCtxt}; +use ty::subst::{Subst, Substs}; +use ty::fold::{TypeFoldable, TypeFolder}; +use util::common::MemoizationMap; + +impl<'a, 'tcx> TyCtxt<'a, 'tcx, 'tcx> { + /// Attempts to resolve an obligation to a vtable.. The result is + /// a shallow vtable resolution -- meaning that we do not + /// (necessarily) resolve all nested obligations on the impl. Note + /// that type check should guarantee to us that all nested + /// obligations *could be* resolved if we wanted to. + pub fn trans_fulfill_obligation(self, + span: Span, + trait_ref: ty::PolyTraitRef<'tcx>) + -> Vtable<'tcx, ()> + { + // Remove any references to regions; this helps improve caching. + let trait_ref = self.erase_regions(&trait_ref); + + self.trans_trait_caches.trait_cache.memoize(trait_ref, || { + debug!("trans::fulfill_obligation(trait_ref={:?}, def_id={:?})", + trait_ref, trait_ref.def_id()); + + // Do the initial selection for the obligation. This yields the + // shallow result we are looking for -- that is, what specific impl. + self.infer_ctxt((), Reveal::All).enter(|infcx| { + let mut selcx = SelectionContext::new(&infcx); + + let obligation_cause = ObligationCause::misc(span, + ast::DUMMY_NODE_ID); + let obligation = Obligation::new(obligation_cause, + trait_ref.to_poly_trait_predicate()); + + let selection = match selcx.select(&obligation) { + Ok(Some(selection)) => selection, + Ok(None) => { + // Ambiguity can happen when monomorphizing during trans + // expands to some humongo type that never occurred + // statically -- this humongo type can then overflow, + // leading to an ambiguous result. So report this as an + // overflow bug, since I believe this is the only case + // where ambiguity can result. + debug!("Encountered ambiguity selecting `{:?}` during trans, \ + presuming due to overflow", + trait_ref); + self.sess.span_fatal(span, + "reached the recursion limit during monomorphization \ + (selection ambiguity)"); + } + Err(e) => { + span_bug!(span, "Encountered error `{:?}` selecting `{:?}` during trans", + e, trait_ref) + } + }; + + debug!("fulfill_obligation: selection={:?}", selection); + + // Currently, we use a fulfillment context to completely resolve + // all nested obligations. This is because they can inform the + // inference of the impl's type parameters. + let mut fulfill_cx = FulfillmentContext::new(); + let vtable = selection.map(|predicate| { + debug!("fulfill_obligation: register_predicate_obligation {:?}", predicate); + fulfill_cx.register_predicate_obligation(&infcx, predicate); + }); + let vtable = infcx.drain_fulfillment_cx_or_panic(span, &mut fulfill_cx, &vtable); + + info!("Cache miss: {:?} => {:?}", trait_ref, vtable); + vtable + }) + }) + } + + /// Monomorphizes a type from the AST by first applying the in-scope + /// substitutions and then normalizing any associated types. + pub fn trans_apply_param_substs<T>(self, + param_substs: &Substs<'tcx>, + value: &T) + -> T + where T: TransNormalize<'tcx> + { + debug!("apply_param_substs(param_substs={:?}, value={:?})", param_substs, value); + let substituted = value.subst(self, param_substs); + let substituted = self.erase_regions(&substituted); + AssociatedTypeNormalizer::new(self).fold(&substituted) + } +} + +struct AssociatedTypeNormalizer<'a, 'gcx: 'a> { + tcx: TyCtxt<'a, 'gcx, 'gcx>, +} + +impl<'a, 'gcx> AssociatedTypeNormalizer<'a, 'gcx> { + fn new(tcx: TyCtxt<'a, 'gcx, 'gcx>) -> Self { + AssociatedTypeNormalizer { tcx } + } + + fn fold<T:TypeFoldable<'gcx>>(&mut self, value: &T) -> T { + if !value.has_projection_types() { + value.clone() + } else { + value.fold_with(self) + } + } +} + +impl<'a, 'gcx> TypeFolder<'gcx, 'gcx> for AssociatedTypeNormalizer<'a, 'gcx> { + fn tcx<'c>(&'c self) -> TyCtxt<'c, 'gcx, 'gcx> { + self.tcx + } + + fn fold_ty(&mut self, ty: Ty<'gcx>) -> Ty<'gcx> { + if !ty.has_projection_types() { + ty + } else { + self.tcx.trans_trait_caches.project_cache.memoize(ty, || { + debug!("AssociatedTypeNormalizer: ty={:?}", ty); + self.tcx.normalize_associated_type(&ty) + }) + } + } +} /// Specializes caches used in trans -- in particular, they assume all /// types are fully monomorphized and that free regions can be erased. pub struct TransTraitCaches<'tcx> { - pub trait_cache: RefCell<DepTrackingMap<TraitSelectionCache<'tcx>>>, - pub project_cache: RefCell<DepTrackingMap<ProjectionCache<'tcx>>>, + trait_cache: RefCell<DepTrackingMap<TraitSelectionCache<'tcx>>>, + project_cache: RefCell<DepTrackingMap<ProjectionCache<'tcx>>>, } impl<'tcx> TransTraitCaches<'tcx> { diff --git a/src/librustc_trans/collector.rs b/src/librustc_trans/collector.rs index ba2b807d5a0..13bb0d37125 100644 --- a/src/librustc_trans/collector.rs +++ b/src/librustc_trans/collector.rs @@ -467,13 +467,11 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> { // have to instantiate all methods of the trait being cast to, so we // can build the appropriate vtable. mir::Rvalue::Cast(mir::CastKind::Unsize, ref operand, target_ty) => { - let target_ty = monomorphize::apply_param_substs(self.scx, - self.param_substs, - &target_ty); + let target_ty = self.scx.tcx().trans_apply_param_substs(self.param_substs, + &target_ty); let source_ty = operand.ty(self.mir, self.scx.tcx()); - let source_ty = monomorphize::apply_param_substs(self.scx, - self.param_substs, - &source_ty); + let source_ty = self.scx.tcx().trans_apply_param_substs(self.param_substs, + &source_ty); let (source_ty, target_ty) = find_vtable_types_for_unsizing(self.scx, source_ty, target_ty); @@ -489,10 +487,8 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> { } mir::Rvalue::Cast(mir::CastKind::ReifyFnPointer, ref operand, _) => { let fn_ty = operand.ty(self.mir, self.scx.tcx()); - let fn_ty = monomorphize::apply_param_substs( - self.scx, - self.param_substs, - &fn_ty); + let fn_ty = self.scx.tcx().trans_apply_param_substs(self.param_substs, + &fn_ty); visit_fn_use(self.scx, fn_ty, false, &mut self.output); } mir::Rvalue::Cast(mir::CastKind::ClosureFnPointer, ref operand, _) => { @@ -534,9 +530,8 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> { } if let mir::Literal::Item { def_id, substs } = constant.literal { - let substs = monomorphize::apply_param_substs(self.scx, - self.param_substs, - &substs); + let substs = self.scx.tcx().trans_apply_param_substs(self.param_substs, + &substs); let instance = monomorphize::resolve(self.scx, def_id, substs); collect_neighbours(self.scx, instance, self.output); } @@ -552,17 +547,14 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> { match *kind { mir::TerminatorKind::Call { ref func, .. } => { let callee_ty = func.ty(self.mir, tcx); - let callee_ty = monomorphize::apply_param_substs( - self.scx, self.param_substs, &callee_ty); + let callee_ty = tcx.trans_apply_param_substs(self.param_substs, &callee_ty); visit_fn_use(self.scx, callee_ty, true, &mut self.output); } mir::TerminatorKind::Drop { ref location, .. } | mir::TerminatorKind::DropAndReplace { ref location, .. } => { let ty = location.ty(self.mir, self.scx.tcx()) .to_ty(self.scx.tcx()); - let ty = monomorphize::apply_param_substs(self.scx, - self.param_substs, - &ty); + let ty = tcx.trans_apply_param_substs(self.param_substs, &ty); visit_drop_use(self.scx, ty, true, self.output); } mir::TerminatorKind::Goto { .. } | diff --git a/src/librustc_trans/common.rs b/src/librustc_trans/common.rs index 5d58c935389..648ea92c843 100644 --- a/src/librustc_trans/common.rs +++ b/src/librustc_trans/common.rs @@ -564,7 +564,7 @@ pub fn def_ty<'a, 'tcx>(shared: &SharedCrateContext<'a, 'tcx>, -> Ty<'tcx> { let ty = shared.tcx().item_type(def_id); - monomorphize::apply_param_substs(shared, substs, &ty) + shared.tcx().trans_apply_param_substs(substs, &ty) } /// Return the substituted type of an instance. @@ -573,5 +573,5 @@ pub fn instance_ty<'a, 'tcx>(shared: &SharedCrateContext<'a, 'tcx>, -> Ty<'tcx> { let ty = instance.def.def_ty(shared.tcx()); - monomorphize::apply_param_substs(shared, instance.substs, &ty) + shared.tcx().trans_apply_param_substs(instance.substs, &ty) } diff --git a/src/librustc_trans/mir/constant.rs b/src/librustc_trans/mir/constant.rs index 8bce0cf85c0..dbae79e034d 100644 --- a/src/librustc_trans/mir/constant.rs +++ b/src/librustc_trans/mir/constant.rs @@ -260,9 +260,7 @@ impl<'a, 'tcx> MirConstContext<'a, 'tcx> { fn monomorphize<T>(&self, value: &T) -> T where T: TransNormalize<'tcx> { - monomorphize::apply_param_substs(self.ccx.shared(), - self.substs, - value) + self.ccx.tcx().trans_apply_param_substs(self.substs, value) } fn trans(&mut self) -> Result<Const<'tcx>, ConstEvalErr<'tcx>> { diff --git a/src/librustc_trans/mir/mod.rs b/src/librustc_trans/mir/mod.rs index 3d8c5085462..2669f722f9c 100644 --- a/src/librustc_trans/mir/mod.rs +++ b/src/librustc_trans/mir/mod.rs @@ -22,7 +22,7 @@ use base; use builder::Builder; use common::{self, CrateContext, Funclet}; use debuginfo::{self, declare_local, VariableAccess, VariableKind, FunctionDebugContext}; -use monomorphize::{self, Instance}; +use monomorphize::Instance; use abi::FnType; use type_of; @@ -102,8 +102,9 @@ pub struct MirContext<'a, 'tcx:'a> { impl<'a, 'tcx> MirContext<'a, 'tcx> { pub fn monomorphize<T>(&self, value: &T) -> T - where T: TransNormalize<'tcx> { - monomorphize::apply_param_substs(self.ccx.shared(), self.param_substs, value) + where T: TransNormalize<'tcx> + { + self.ccx.tcx().trans_apply_param_substs(self.param_substs, value) } pub fn set_debug_loc(&mut self, bcx: &Builder, source_info: mir::SourceInfo) { diff --git a/src/librustc_trans/monomorphize.rs b/src/librustc_trans/monomorphize.rs index 33626e7c39f..d27eeb2b646 100644 --- a/src/librustc_trans/monomorphize.rs +++ b/src/librustc_trans/monomorphize.rs @@ -13,17 +13,13 @@ use common::*; use glue; use rustc::hir::def_id::DefId; -use rustc::infer::TransNormalize; use rustc::middle::lang_items::DropInPlaceFnLangItem; -use rustc::traits::{self, SelectionContext, Reveal}; +use rustc::traits; use rustc::ty::adjustment::CustomCoerceUnsized; -use rustc::ty::fold::{TypeFolder, TypeFoldable}; use rustc::ty::subst::{Kind, Subst, Substs}; use rustc::ty::{self, Ty, TyCtxt}; -use rustc::util::common::MemoizationMap; -use syntax::ast; -use syntax::codemap::{Span, DUMMY_SP}; +use syntax::codemap::DUMMY_SP; pub use rustc::ty::Instance; @@ -104,73 +100,6 @@ pub fn resolve_closure<'a, 'tcx> ( } } -/// Attempts to resolve an obligation. The result is a shallow vtable resolution -- meaning that we -/// do not (necessarily) resolve all nested obligations on the impl. Note that type check should -/// guarantee to us that all nested obligations *could be* resolved if we wanted to. -fn fulfill_obligation<'a, 'tcx>(scx: &SharedCrateContext<'a, 'tcx>, - span: Span, - trait_ref: ty::PolyTraitRef<'tcx>) - -> traits::Vtable<'tcx, ()> -{ - let tcx = scx.tcx(); - - // Remove any references to regions; this helps improve caching. - let trait_ref = tcx.erase_regions(&trait_ref); - - tcx.trans_trait_caches.trait_cache.memoize(trait_ref, || { - debug!("trans::fulfill_obligation(trait_ref={:?}, def_id={:?})", - trait_ref, trait_ref.def_id()); - - // Do the initial selection for the obligation. This yields the - // shallow result we are looking for -- that is, what specific impl. - tcx.infer_ctxt((), Reveal::All).enter(|infcx| { - let mut selcx = SelectionContext::new(&infcx); - - let obligation_cause = traits::ObligationCause::misc(span, - ast::DUMMY_NODE_ID); - let obligation = traits::Obligation::new(obligation_cause, - trait_ref.to_poly_trait_predicate()); - - let selection = match selcx.select(&obligation) { - Ok(Some(selection)) => selection, - Ok(None) => { - // Ambiguity can happen when monomorphizing during trans - // expands to some humongo type that never occurred - // statically -- this humongo type can then overflow, - // leading to an ambiguous result. So report this as an - // overflow bug, since I believe this is the only case - // where ambiguity can result. - debug!("Encountered ambiguity selecting `{:?}` during trans, \ - presuming due to overflow", - trait_ref); - tcx.sess.span_fatal(span, - "reached the recursion limit during monomorphization \ - (selection ambiguity)"); - } - Err(e) => { - span_bug!(span, "Encountered error `{:?}` selecting `{:?}` during trans", - e, trait_ref) - } - }; - - debug!("fulfill_obligation: selection={:?}", selection); - - // Currently, we use a fulfillment context to completely resolve - // all nested obligations. This is because they can inform the - // inference of the impl's type parameters. - let mut fulfill_cx = traits::FulfillmentContext::new(); - let vtable = selection.map(|predicate| { - debug!("fulfill_obligation: register_predicate_obligation {:?}", predicate); - fulfill_cx.register_predicate_obligation(&infcx, predicate); - }); - let vtable = infcx.drain_fulfillment_cx_or_panic(span, &mut fulfill_cx, &vtable); - - info!("Cache miss: {:?} => {:?}", trait_ref, vtable); - vtable - }) - }) -} - fn resolve_associated_item<'a, 'tcx>( scx: &SharedCrateContext<'a, 'tcx>, trait_item: &ty::AssociatedItem, @@ -185,7 +114,7 @@ fn resolve_associated_item<'a, 'tcx>( def_id, trait_id, rcvr_substs); let trait_ref = ty::TraitRef::from_method(tcx, trait_id, rcvr_substs); - let vtbl = fulfill_obligation(scx, DUMMY_SP, ty::Binder(trait_ref)); + let vtbl = tcx.trans_fulfill_obligation(DUMMY_SP, ty::Binder(trait_ref)); // Now that we know which impl is being used, we can dispatch to // the actual function: @@ -285,7 +214,7 @@ pub fn custom_coerce_unsize_info<'scx, 'tcx>(scx: &SharedCrateContext<'scx, 'tcx substs: scx.tcx().mk_substs_trait(source_ty, &[target_ty]) }); - match fulfill_obligation(scx, DUMMY_SP, trait_ref) { + match scx.tcx().trans_fulfill_obligation(DUMMY_SP, trait_ref) { traits::VtableImpl(traits::VtableImplData { impl_def_id, .. }) => { scx.tcx().coerce_unsized_info(impl_def_id).custom_kind.unwrap() } @@ -295,21 +224,6 @@ pub fn custom_coerce_unsize_info<'scx, 'tcx>(scx: &SharedCrateContext<'scx, 'tcx } } -/// Monomorphizes a type from the AST by first applying the in-scope -/// substitutions and then normalizing any associated types. -pub fn apply_param_substs<'a, 'tcx, T>(scx: &SharedCrateContext<'a, 'tcx>, - param_substs: &Substs<'tcx>, - value: &T) - -> T - where T: TransNormalize<'tcx> -{ - let tcx = scx.tcx(); - debug!("apply_param_substs(param_substs={:?}, value={:?})", param_substs, value); - let substituted = value.subst(tcx, param_substs); - let substituted = scx.tcx().erase_regions(&substituted); - AssociatedTypeNormalizer::new(tcx).fold(&substituted) -} - /// Returns the normalized type of a struct field pub fn field_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, param_substs: &Substs<'tcx>, @@ -319,37 +233,3 @@ pub fn field_ty<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, tcx.normalize_associated_type(&f.ty(tcx, param_substs)) } -struct AssociatedTypeNormalizer<'a, 'gcx: 'a> { - tcx: TyCtxt<'a, 'gcx, 'gcx>, -} - -impl<'a, 'gcx> AssociatedTypeNormalizer<'a, 'gcx> { - fn new(tcx: TyCtxt<'a, 'gcx, 'gcx>) -> Self { - AssociatedTypeNormalizer { tcx } - } - - fn fold<T:TypeFoldable<'gcx>>(&mut self, value: &T) -> T { - if !value.has_projection_types() { - value.clone() - } else { - value.fold_with(self) - } - } -} - -impl<'a, 'gcx> TypeFolder<'gcx, 'gcx> for AssociatedTypeNormalizer<'a, 'gcx> { - fn tcx<'c>(&'c self) -> TyCtxt<'c, 'gcx, 'gcx> { - self.tcx - } - - fn fold_ty(&mut self, ty: Ty<'gcx>) -> Ty<'gcx> { - if !ty.has_projection_types() { - ty - } else { - self.tcx.trans_trait_caches.project_cache.memoize(ty, || { - debug!("AssociatedTypeNormalizer: ty={:?}", ty); - self.tcx.normalize_associated_type(&ty) - }) - } - } -} |