diff options
Diffstat (limited to 'src/librustc/middle/mem_categorization.rs')
| -rw-r--r-- | src/librustc/middle/mem_categorization.rs | 169 |
1 files changed, 118 insertions, 51 deletions
diff --git a/src/librustc/middle/mem_categorization.rs b/src/librustc/middle/mem_categorization.rs index 2d9bb2af1b2..3738e38f687 100644 --- a/src/librustc/middle/mem_categorization.rs +++ b/src/librustc/middle/mem_categorization.rs @@ -71,6 +71,8 @@ pub use self::Note::*; pub use self::deref_kind::*; pub use self::categorization::*; +use self::Aliasability::*; + use middle::check_const; use middle::def; use middle::region; @@ -295,23 +297,29 @@ pub trait Typer<'tcx> : ty::ClosureTyper<'tcx> { impl MutabilityCategory { pub fn from_mutbl(m: ast::Mutability) -> MutabilityCategory { - match m { + let ret = match m { MutImmutable => McImmutable, MutMutable => McDeclared - } + }; + debug!("MutabilityCategory::{}({:?}) => {:?}", + "from_mutbl", m, ret); + ret } pub fn from_borrow_kind(borrow_kind: ty::BorrowKind) -> MutabilityCategory { - match borrow_kind { + let ret = match borrow_kind { ty::ImmBorrow => McImmutable, ty::UniqueImmBorrow => McImmutable, ty::MutBorrow => McDeclared, - } + }; + debug!("MutabilityCategory::{}({:?}) => {:?}", + "from_borrow_kind", borrow_kind, ret); + ret } - pub fn from_pointer_kind(base_mutbl: MutabilityCategory, - ptr: PointerKind) -> MutabilityCategory { - match ptr { + fn from_pointer_kind(base_mutbl: MutabilityCategory, + ptr: PointerKind) -> MutabilityCategory { + let ret = match ptr { Unique => { base_mutbl.inherit() } @@ -321,11 +329,14 @@ impl MutabilityCategory { UnsafePtr(m) => { MutabilityCategory::from_mutbl(m) } - } + }; + debug!("MutabilityCategory::{}({:?}, {:?}) => {:?}", + "from_pointer_kind", base_mutbl, ptr, ret); + ret } fn from_local(tcx: &ty::ctxt, id: ast::NodeId) -> MutabilityCategory { - match tcx.map.get(id) { + let ret = match tcx.map.get(id) { ast_map::NodeLocal(p) | ast_map::NodeArg(p) => match p.node { ast::PatIdent(bind_mode, _, _) => { if bind_mode == ast::BindByValue(ast::MutMutable) { @@ -337,30 +348,39 @@ impl MutabilityCategory { _ => tcx.sess.span_bug(p.span, "expected identifier pattern") }, _ => tcx.sess.span_bug(tcx.map.span(id), "expected identifier pattern") - } + }; + debug!("MutabilityCategory::{}(tcx, id={:?}) => {:?}", + "from_local", id, ret); + ret } pub fn inherit(&self) -> MutabilityCategory { - match *self { + let ret = match *self { McImmutable => McImmutable, McDeclared => McInherited, McInherited => McInherited, - } + }; + debug!("{:?}.inherit() => {:?}", self, ret); + ret } pub fn is_mutable(&self) -> bool { - match *self { + let ret = match *self { McImmutable => false, McInherited => true, McDeclared => true, - } + }; + debug!("{:?}.is_mutable() => {:?}", self, ret); + ret } pub fn is_immutable(&self) -> bool { - match *self { + let ret = match *self { McImmutable => true, McDeclared | McInherited => false - } + }; + debug!("{:?}.is_immutable() => {:?}", self, ret); + ret } pub fn to_user_str(&self) -> &'static str { @@ -733,7 +753,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { } }; - Ok(Rc::new(cmt_result)) + let ret = Rc::new(cmt_result); + debug!("cat_upvar ret={}", ret.repr(self.tcx())); + Ok(ret) } fn env_deref(&self, @@ -794,14 +816,18 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { McDeclared | McInherited => { } } - cmt_ { + let ret = cmt_ { id: id, span: span, cat: cat_deref(Rc::new(cmt_result), 0, env_ptr), mutbl: deref_mutbl, ty: var_ty, note: NoteClosureEnv(upvar_id) - } + }; + + debug!("env_deref ret {}", ret.repr(self.tcx())); + + ret } pub fn cat_rvalue_node(&self, @@ -831,7 +857,9 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { } } }; - self.cat_rvalue(id, span, re, expr_ty) + let ret = self.cat_rvalue(id, span, re, expr_ty); + debug!("cat_rvalue_node ret {}", ret.repr(self.tcx())); + ret } pub fn cat_rvalue(&self, @@ -839,14 +867,16 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { span: Span, temp_scope: ty::Region, expr_ty: Ty<'tcx>) -> cmt<'tcx> { - Rc::new(cmt_ { + let ret = Rc::new(cmt_ { id:cmt_id, span:span, cat:cat_rvalue(temp_scope), mutbl:McDeclared, ty:expr_ty, note: NoteNone - }) + }); + debug!("cat_rvalue ret {}", ret.repr(self.tcx())); + ret } pub fn cat_field<N:ast_node>(&self, @@ -855,14 +885,16 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { f_name: ast::Name, f_ty: Ty<'tcx>) -> cmt<'tcx> { - Rc::new(cmt_ { + let ret = Rc::new(cmt_ { id: node.id(), span: node.span(), mutbl: base_cmt.mutbl.inherit(), cat: cat_interior(base_cmt, InteriorField(NamedField(f_name))), ty: f_ty, note: NoteNone - }) + }); + debug!("cat_field ret {}", ret.repr(self.tcx())); + ret } pub fn cat_tup_field<N:ast_node>(&self, @@ -871,14 +903,16 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { f_idx: usize, f_ty: Ty<'tcx>) -> cmt<'tcx> { - Rc::new(cmt_ { + let ret = Rc::new(cmt_ { id: node.id(), span: node.span(), mutbl: base_cmt.mutbl.inherit(), cat: cat_interior(base_cmt, InteriorField(PositionalField(f_idx))), ty: f_ty, note: NoteNone - }) + }); + debug!("cat_tup_field ret {}", ret.repr(self.tcx())); + ret } fn cat_deref<N:ast_node>(&self, @@ -913,10 +947,14 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { }; let base_cmt_ty = base_cmt.ty; match ty::deref(base_cmt_ty, true) { - Some(mt) => self.cat_deref_common(node, base_cmt, deref_cnt, + Some(mt) => { + let ret = self.cat_deref_common(node, base_cmt, deref_cnt, mt.ty, deref_context, - /* implicit: */ false), + /* implicit: */ false); + debug!("cat_deref ret {}", ret.repr(self.tcx())); + ret + } None => { debug!("Explicit deref of non-derefable type: {}", base_cmt_ty.repr(self.tcx())); @@ -954,14 +992,16 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { (base_cmt.mutbl.inherit(), cat_interior(base_cmt, interior)) } }; - Ok(Rc::new(cmt_ { + let ret = Rc::new(cmt_ { id: node.id(), span: node.span(), cat: cat, mutbl: m, ty: deref_ty, note: NoteNone - })) + }); + debug!("cat_deref_common ret {}", ret.repr(self.tcx())); + Ok(ret) } pub fn cat_index<N:ast_node>(&self, @@ -1009,8 +1049,10 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { }; let m = base_cmt.mutbl.inherit(); - return Ok(interior(elt, base_cmt.clone(), base_cmt.ty, - m, context, element_ty)); + let ret = interior(elt, base_cmt.clone(), base_cmt.ty, + m, context, element_ty); + debug!("cat_index ret {}", ret.repr(self.tcx())); + return Ok(ret); fn interior<'tcx, N: ast_node>(elt: &N, of_cmt: cmt<'tcx>, @@ -1039,14 +1081,14 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { context: InteriorOffsetKind) -> McResult<cmt<'tcx>> { - match try!(deref_kind(base_cmt.ty, Some(context))) { + let ret = match try!(deref_kind(base_cmt.ty, Some(context))) { deref_ptr(ptr) => { // for unique ptrs, we inherit mutability from the // owning reference. let m = MutabilityCategory::from_pointer_kind(base_cmt.mutbl, ptr); // the deref is explicit in the resulting cmt - Ok(Rc::new(cmt_ { + Rc::new(cmt_ { id:elt.id(), span:elt.span(), cat:cat_deref(base_cmt.clone(), 0, ptr), @@ -1056,13 +1098,15 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { None => self.tcx().sess.bug("Found non-derefable type") }, note: NoteNone - })) + }) } deref_interior(_) => { - Ok(base_cmt) + base_cmt } - } + }; + debug!("deref_vec ret {}", ret.repr(self.tcx())); + Ok(ret) } /// Given a pattern P like: `[_, ..Q, _]`, where `vec_cmt` is the cmt for `P`, `slice_pat` is @@ -1112,14 +1156,16 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { interior_ty: Ty<'tcx>, interior: InteriorKind) -> cmt<'tcx> { - Rc::new(cmt_ { + let ret = Rc::new(cmt_ { id: node.id(), span: node.span(), mutbl: base_cmt.mutbl.inherit(), cat: cat_interior(base_cmt, interior), ty: interior_ty, note: NoteNone - }) + }); + debug!("cat_imm_interior ret={}", ret.repr(self.tcx())); + ret } pub fn cat_downcast<N:ast_node>(&self, @@ -1128,14 +1174,16 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { downcast_ty: Ty<'tcx>, variant_did: ast::DefId) -> cmt<'tcx> { - Rc::new(cmt_ { + let ret = Rc::new(cmt_ { id: node.id(), span: node.span(), mutbl: base_cmt.mutbl.inherit(), cat: cat_downcast(base_cmt, variant_did), ty: downcast_ty, note: NoteNone - }) + }); + debug!("cat_downcast ret={}", ret.repr(self.tcx())); + ret } pub fn cat_pattern<F>(&self, cmt: cmt<'tcx>, pat: &ast::Pat, mut op: F) -> McResult<()> @@ -1341,17 +1389,25 @@ impl<'t,'tcx,TYPER:Typer<'tcx>> MemCategorizationContext<'t,TYPER> { } } -#[derive(Copy)] +#[derive(Copy, Clone, Debug)] pub enum InteriorSafety { InteriorUnsafe, InteriorSafe } -#[derive(Copy)] +#[derive(Clone, Debug)] +pub enum Aliasability { + FreelyAliasable(AliasableReason), + NonAliasable, + ImmutableUnique(Box<Aliasability>), +} + +#[derive(Copy, Clone, Debug)] pub enum AliasableReason { AliasableBorrowed, AliasableClosure(ast::NodeId), // Aliasable due to capture Fn closure env AliasableOther, + UnaliasableImmutable, // Created as needed upon seeing ImmutableUnique AliasableStatic(InteriorSafety), AliasableStaticMut(InteriorSafety), } @@ -1380,9 +1436,9 @@ impl<'tcx> cmt_<'tcx> { } } - /// Returns `Some(_)` if this lvalue represents a freely aliasable pointer type. + /// Returns `FreelyAliasable(_)` if this lvalue represents a freely aliasable pointer type. pub fn freely_aliasable(&self, ctxt: &ty::ctxt<'tcx>) - -> Option<AliasableReason> { + -> Aliasability { // Maybe non-obvious: copied upvars can only be considered // non-aliasable in once closures, since any other kind can be // aliased and eventually recused. @@ -1393,17 +1449,27 @@ impl<'tcx> cmt_<'tcx> { cat_deref(ref b, _, BorrowedPtr(ty::UniqueImmBorrow, _)) | cat_deref(ref b, _, Implicit(ty::UniqueImmBorrow, _)) | cat_downcast(ref b, _) | - cat_deref(ref b, _, Unique) | cat_interior(ref b, _) => { // Aliasability depends on base cmt b.freely_aliasable(ctxt) } + cat_deref(ref b, _, Unique) => { + let sub = b.freely_aliasable(ctxt); + if b.mutbl.is_mutable() { + // Aliasability depends on base cmt alone + sub + } else { + // Do not allow mutation through an immutable box. + ImmutableUnique(Box::new(sub)) + } + } + cat_rvalue(..) | cat_local(..) | cat_upvar(..) | cat_deref(_, _, UnsafePtr(..)) => { // yes, it's aliasable, but... - None + NonAliasable } cat_static_item(..) => { @@ -1414,17 +1480,18 @@ impl<'tcx> cmt_<'tcx> { }; if self.mutbl.is_mutable() { - Some(AliasableStaticMut(int_safe)) + FreelyAliasable(AliasableStaticMut(int_safe)) } else { - Some(AliasableStatic(int_safe)) + FreelyAliasable(AliasableStatic(int_safe)) } } cat_deref(ref base, _, BorrowedPtr(ty::ImmBorrow, _)) | cat_deref(ref base, _, Implicit(ty::ImmBorrow, _)) => { match base.cat { - cat_upvar(Upvar{ id, .. }) => Some(AliasableClosure(id.closure_expr_id)), - _ => Some(AliasableBorrowed) + cat_upvar(Upvar{ id, .. }) => + FreelyAliasable(AliasableClosure(id.closure_expr_id)), + _ => FreelyAliasable(AliasableBorrowed) } } } |