| // Copyright 2012-2015 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 ty::subst; |
| use ty::{self, Ty, TypeFlags, TypeFoldable}; |
| |
| pub struct FlagComputation { |
| pub flags: TypeFlags, |
| |
| // maximum depth of any bound region that we have seen thus far |
| pub depth: u32, |
| } |
| |
| impl FlagComputation { |
| fn new() -> FlagComputation { |
| FlagComputation { flags: TypeFlags::empty(), depth: 0 } |
| } |
| |
| pub fn for_sty(st: &ty::TypeVariants) -> FlagComputation { |
| let mut result = FlagComputation::new(); |
| result.add_sty(st); |
| result |
| } |
| |
| fn add_flags(&mut self, flags: TypeFlags) { |
| self.flags = self.flags | (flags & TypeFlags::NOMINAL_FLAGS); |
| } |
| |
| fn add_depth(&mut self, depth: u32) { |
| if depth > self.depth { |
| self.depth = depth; |
| } |
| } |
| |
| /// Adds the flags/depth from a set of types that appear within the current type, but within a |
| /// region binder. |
| fn add_bound_computation(&mut self, computation: &FlagComputation) { |
| self.add_flags(computation.flags); |
| |
| // The types that contributed to `computation` occurred within |
| // a region binder, so subtract one from the region depth |
| // within when adding the depth to `self`. |
| let depth = computation.depth; |
| if depth > 0 { |
| self.add_depth(depth - 1); |
| } |
| } |
| |
| fn add_sty(&mut self, st: &ty::TypeVariants) { |
| match st { |
| &ty::TyBool | |
| &ty::TyChar | |
| &ty::TyInt(_) | |
| &ty::TyFloat(_) | |
| &ty::TyUint(_) | |
| &ty::TyStr => { |
| } |
| |
| // You might think that we could just return TyError for |
| // any type containing TyError as a component, and get |
| // rid of the TypeFlags::HAS_TY_ERR flag -- likewise for ty_bot (with |
| // the exception of function types that return bot). |
| // But doing so caused sporadic memory corruption, and |
| // neither I (tjc) nor nmatsakis could figure out why, |
| // so we're doing it this way. |
| &ty::TyError => { |
| self.add_flags(TypeFlags::HAS_TY_ERR) |
| } |
| |
| &ty::TyParam(ref p) => { |
| self.add_flags(TypeFlags::HAS_LOCAL_NAMES); |
| if p.space == subst::SelfSpace { |
| self.add_flags(TypeFlags::HAS_SELF); |
| } else { |
| self.add_flags(TypeFlags::HAS_PARAMS); |
| } |
| } |
| |
| &ty::TyClosure(_, ref substs) => { |
| self.add_flags(TypeFlags::HAS_TY_CLOSURE); |
| self.add_flags(TypeFlags::HAS_LOCAL_NAMES); |
| self.add_substs(&substs.func_substs); |
| self.add_tys(&substs.upvar_tys); |
| } |
| |
| &ty::TyInfer(infer) => { |
| self.add_flags(TypeFlags::HAS_LOCAL_NAMES); // it might, right? |
| self.add_flags(TypeFlags::HAS_TY_INFER); |
| match infer { |
| ty::FreshTy(_) | |
| ty::FreshIntTy(_) | |
| ty::FreshFloatTy(_) => {} |
| _ => self.add_flags(TypeFlags::KEEP_IN_LOCAL_TCX) |
| } |
| } |
| |
| &ty::TyEnum(_, substs) | &ty::TyStruct(_, substs) => { |
| self.add_substs(substs); |
| } |
| |
| &ty::TyProjection(ref data) => { |
| self.add_flags(TypeFlags::HAS_PROJECTION); |
| self.add_projection_ty(data); |
| } |
| |
| &ty::TyTrait(box ty::TraitTy { ref principal, ref bounds }) => { |
| let mut computation = FlagComputation::new(); |
| computation.add_substs(principal.0.substs); |
| for projection_bound in &bounds.projection_bounds { |
| let mut proj_computation = FlagComputation::new(); |
| proj_computation.add_projection_predicate(&projection_bound.0); |
| self.add_bound_computation(&proj_computation); |
| } |
| self.add_bound_computation(&computation); |
| |
| self.add_bounds(bounds); |
| } |
| |
| &ty::TyBox(tt) | &ty::TyArray(tt, _) | &ty::TySlice(tt) => { |
| self.add_ty(tt) |
| } |
| |
| &ty::TyRawPtr(ref m) => { |
| self.add_ty(m.ty); |
| } |
| |
| &ty::TyRef(r, ref m) => { |
| self.add_region(*r); |
| self.add_ty(m.ty); |
| } |
| |
| &ty::TyTuple(ref ts) => { |
| self.add_tys(&ts[..]); |
| } |
| |
| &ty::TyFnDef(_, substs, ref f) => { |
| self.add_substs(substs); |
| self.add_fn_sig(&f.sig); |
| } |
| |
| &ty::TyFnPtr(ref f) => { |
| self.add_fn_sig(&f.sig); |
| } |
| } |
| } |
| |
| fn add_ty(&mut self, ty: Ty) { |
| self.add_flags(ty.flags.get()); |
| self.add_depth(ty.region_depth); |
| } |
| |
| fn add_tys(&mut self, tys: &[Ty]) { |
| for &ty in tys { |
| self.add_ty(ty); |
| } |
| } |
| |
| fn add_fn_sig(&mut self, fn_sig: &ty::PolyFnSig) { |
| let mut computation = FlagComputation::new(); |
| |
| computation.add_tys(&fn_sig.0.inputs); |
| |
| if let ty::FnConverging(output) = fn_sig.0.output { |
| computation.add_ty(output); |
| } |
| |
| self.add_bound_computation(&computation); |
| } |
| |
| fn add_region(&mut self, r: ty::Region) { |
| match r { |
| ty::ReVar(..) => { |
| self.add_flags(TypeFlags::HAS_RE_INFER); |
| self.add_flags(TypeFlags::KEEP_IN_LOCAL_TCX); |
| } |
| ty::ReSkolemized(..) => { |
| self.add_flags(TypeFlags::HAS_RE_INFER); |
| self.add_flags(TypeFlags::HAS_RE_SKOL); |
| self.add_flags(TypeFlags::KEEP_IN_LOCAL_TCX); |
| } |
| ty::ReLateBound(debruijn, _) => { self.add_depth(debruijn.depth); } |
| ty::ReEarlyBound(..) => { self.add_flags(TypeFlags::HAS_RE_EARLY_BOUND); } |
| ty::ReStatic | ty::ReErased => {} |
| _ => { self.add_flags(TypeFlags::HAS_FREE_REGIONS); } |
| } |
| |
| if !r.is_global() { |
| self.add_flags(TypeFlags::HAS_LOCAL_NAMES); |
| } |
| } |
| |
| fn add_projection_predicate(&mut self, projection_predicate: &ty::ProjectionPredicate) { |
| self.add_projection_ty(&projection_predicate.projection_ty); |
| self.add_ty(projection_predicate.ty); |
| } |
| |
| fn add_projection_ty(&mut self, projection_ty: &ty::ProjectionTy) { |
| self.add_substs(projection_ty.trait_ref.substs); |
| } |
| |
| fn add_substs(&mut self, substs: &subst::Substs) { |
| self.add_tys(substs.types.as_slice()); |
| for &r in &substs.regions { |
| self.add_region(r); |
| } |
| } |
| |
| fn add_bounds(&mut self, bounds: &ty::ExistentialBounds) { |
| self.add_region(bounds.region_bound); |
| } |
| } |