diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs index 6589e824187fd..6ee4395395800 100644 --- a/src/librustc/mir/visit.rs +++ b/src/librustc/mir/visit.rs @@ -256,7 +256,9 @@ macro_rules! make_mir_visitor { } fn visit_local(&mut self, - _local: & $($mutability)* Local) { + _local: & $($mutability)* Local, + _context: LvalueContext<'tcx>, + _location: Location) { } fn visit_visibility_scope(&mut self, @@ -610,7 +612,7 @@ macro_rules! make_mir_visitor { location: Location) { match *lvalue { Lvalue::Local(ref $($mutability)* local) => { - self.visit_local(local); + self.visit_local(local, context, location); } Lvalue::Static(ref $($mutability)* static_) => { self.visit_static(static_, context, location); diff --git a/src/librustc_mir/transform/copy_prop.rs b/src/librustc_mir/transform/copy_prop.rs index 186c465f60105..ac8ebd306d321 100644 --- a/src/librustc_mir/transform/copy_prop.rs +++ b/src/librustc_mir/transform/copy_prop.rs @@ -236,8 +236,7 @@ impl<'tcx> Action<'tcx> { } // Replace all uses of the destination local with the source local. - let src_lvalue = Lvalue::Local(src_local); - def_use_analysis.replace_all_defs_and_uses_with(dest_local, mir, src_lvalue); + def_use_analysis.replace_all_defs_and_uses_with(dest_local, mir, src_local); // Finally, zap the now-useless assignment instruction. debug!(" Deleting assignment"); diff --git a/src/librustc_mir/transform/generator.rs b/src/librustc_mir/transform/generator.rs index 9bc572c66b6f8..8328bb9461ede 100644 --- a/src/librustc_mir/transform/generator.rs +++ b/src/librustc_mir/transform/generator.rs @@ -88,7 +88,9 @@ struct RenameLocalVisitor { impl<'tcx> MutVisitor<'tcx> for RenameLocalVisitor { fn visit_local(&mut self, - local: &mut Local) { + local: &mut Local, + _: LvalueContext<'tcx>, + _: Location) { if *local == self.from { *local = self.to; } @@ -98,6 +100,13 @@ impl<'tcx> MutVisitor<'tcx> for RenameLocalVisitor { struct DerefArgVisitor; impl<'tcx> MutVisitor<'tcx> for DerefArgVisitor { + fn visit_local(&mut self, + local: &mut Local, + _: LvalueContext<'tcx>, + _: Location) { + assert_ne!(*local, self_arg()); + } + fn visit_lvalue(&mut self, lvalue: &mut Lvalue<'tcx>, context: LvalueContext<'tcx>, @@ -177,6 +186,13 @@ impl<'a, 'tcx> TransformVisitor<'a, 'tcx> { } impl<'a, 'tcx> MutVisitor<'tcx> for TransformVisitor<'a, 'tcx> { + fn visit_local(&mut self, + local: &mut Local, + _: LvalueContext<'tcx>, + _: Location) { + assert_eq!(self.remap.get(local), None); + } + fn visit_lvalue(&mut self, lvalue: &mut Lvalue<'tcx>, context: LvalueContext<'tcx>, diff --git a/src/librustc_mir/transform/inline.rs b/src/librustc_mir/transform/inline.rs index 124a1ef946e2b..3f8070fb3aa31 100644 --- a/src/librustc_mir/transform/inline.rs +++ b/src/librustc_mir/transform/inline.rs @@ -589,16 +589,6 @@ impl<'a, 'tcx> Integrator<'a, 'tcx> { new } - fn update_local(&self, local: Local) -> Option { - let idx = local.index(); - if idx < (self.args.len() + 1) { - return None; - } - let idx = idx - (self.args.len() + 1); - let local = Local::new(idx); - self.local_map.get(local).cloned() - } - fn arg_index(&self, arg: Local) -> Option { let idx = arg.index(); if idx > 0 && idx <= self.args.len() { @@ -610,32 +600,35 @@ impl<'a, 'tcx> Integrator<'a, 'tcx> { } impl<'a, 'tcx> MutVisitor<'tcx> for Integrator<'a, 'tcx> { + fn visit_local(&mut self, + local: &mut Local, + _ctxt: LvalueContext<'tcx>, + _location: Location) { + if *local == RETURN_POINTER { + match self.destination { + Lvalue::Local(l) => *local = l, + ref lval => bug!("Return lvalue is {:?}, not local", lval) + } + } + let idx = local.index() - 1; + if idx < self.args.len() { + match self.args[idx] { + Operand::Consume(Lvalue::Local(l)) => *local = l, + ref op => bug!("Arg operand `{:?}` is {:?}, not local", idx, op) + } + } + *local = self.local_map[Local::new(idx - self.args.len())]; + } + fn visit_lvalue(&mut self, lvalue: &mut Lvalue<'tcx>, _ctxt: LvalueContext<'tcx>, _location: Location) { - if let Lvalue::Local(ref mut local) = *lvalue { - if let Some(l) = self.update_local(*local) { - // Temp or Var; update the local reference - *local = l; - return; - } - } - if let Lvalue::Local(local) = *lvalue { - if local == RETURN_POINTER { - // Return pointer; update the lvalue itself - *lvalue = self.destination.clone(); - } else if local.index() < (self.args.len() + 1) { - // Argument, once again update the the lvalue itself - let idx = local.index() - 1; - if let Operand::Consume(ref lval) = self.args[idx] { - *lvalue = lval.clone(); - } else { - bug!("Arg operand `{:?}` is not an Lvalue use.", idx) - } - } + if let Lvalue::Local(RETURN_POINTER) = *lvalue { + // Return pointer; update the lvalue itself + *lvalue = self.destination.clone(); } else { - self.super_lvalue(lvalue, _ctxt, _location) + self.super_lvalue(lvalue, _ctxt, _location); } } diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs index 3e136fb9e9c49..53191806981a0 100644 --- a/src/librustc_mir/transform/promote_consts.rs +++ b/src/librustc_mir/transform/promote_consts.rs @@ -83,52 +83,49 @@ struct TempCollector<'tcx> { } impl<'tcx> Visitor<'tcx> for TempCollector<'tcx> { - fn visit_lvalue(&mut self, - lvalue: &Lvalue<'tcx>, - context: LvalueContext<'tcx>, - location: Location) { - self.super_lvalue(lvalue, context, location); - if let Lvalue::Local(index) = *lvalue { - // We're only interested in temporaries - if self.mir.local_kind(index) != LocalKind::Temp { - return; - } + fn visit_local(&mut self, + &index: &Local, + context: LvalueContext<'tcx>, + location: Location) { + // We're only interested in temporaries + if self.mir.local_kind(index) != LocalKind::Temp { + return; + } - // Ignore drops, if the temp gets promoted, - // then it's constant and thus drop is noop. - // Storage live ranges are also irrelevant. - if context.is_drop() || context.is_storage_marker() { - return; - } + // Ignore drops, if the temp gets promoted, + // then it's constant and thus drop is noop. + // Storage live ranges are also irrelevant. + if context.is_drop() || context.is_storage_marker() { + return; + } - let temp = &mut self.temps[index]; - if *temp == TempState::Undefined { - match context { - LvalueContext::Store | - LvalueContext::Call => { - *temp = TempState::Defined { - location, - uses: 0 - }; - return; - } - _ => { /* mark as unpromotable below */ } - } - } else if let TempState::Defined { ref mut uses, .. } = *temp { - // We always allow borrows, even mutable ones, as we need - // to promote mutable borrows of some ZSTs e.g. `&mut []`. - let allowed_use = match context { - LvalueContext::Borrow {..} => true, - _ => context.is_nonmutating_use() - }; - if allowed_use { - *uses += 1; + let temp = &mut self.temps[index]; + if *temp == TempState::Undefined { + match context { + LvalueContext::Store | + LvalueContext::Call => { + *temp = TempState::Defined { + location, + uses: 0 + }; return; } - /* mark as unpromotable below */ + _ => { /* mark as unpromotable below */ } } - *temp = TempState::Unpromotable; + } else if let TempState::Defined { ref mut uses, .. } = *temp { + // We always allow borrows, even mutable ones, as we need + // to promote mutable borrows of some ZSTs e.g. `&mut []`. + let allowed_use = match context { + LvalueContext::Borrow {..} => true, + _ => context.is_nonmutating_use() + }; + if allowed_use { + *uses += 1; + return; + } + /* mark as unpromotable below */ } + *temp = TempState::Unpromotable; } fn visit_source_info(&mut self, source_info: &SourceInfo) { @@ -326,16 +323,13 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> { /// Replaces all temporaries with their promoted counterparts. impl<'a, 'tcx> MutVisitor<'tcx> for Promoter<'a, 'tcx> { - fn visit_lvalue(&mut self, - lvalue: &mut Lvalue<'tcx>, - context: LvalueContext<'tcx>, - location: Location) { - if let Lvalue::Local(ref mut temp) = *lvalue { - if self.source.local_kind(*temp) == LocalKind::Temp { - *temp = self.promote_temp(*temp); - } + fn visit_local(&mut self, + local: &mut Local, + _: LvalueContext<'tcx>, + _: Location) { + if self.source.local_kind(*local) == LocalKind::Temp { + *local = self.promote_temp(*local); } - self.super_lvalue(lvalue, context, location); } } diff --git a/src/librustc_mir/transform/qualify_consts.rs b/src/librustc_mir/transform/qualify_consts.rs index 9e64b0f9c77be..99e9f638a749b 100644 --- a/src/librustc_mir/transform/qualify_consts.rs +++ b/src/librustc_mir/transform/qualify_consts.rs @@ -499,33 +499,40 @@ impl<'a, 'tcx> Qualifier<'a, 'tcx, 'tcx> { /// For functions (constant or not), it also records /// candidates for promotion in promotion_candidates. impl<'a, 'tcx> Visitor<'tcx> for Qualifier<'a, 'tcx, 'tcx> { + fn visit_local(&mut self, + &local: &Local, + _: LvalueContext<'tcx>, + _: Location) { + match self.mir.local_kind(local) { + LocalKind::ReturnPointer => { + self.not_const(); + } + LocalKind::Arg => { + self.add(Qualif::FN_ARGUMENT); + } + LocalKind::Var => { + self.add(Qualif::NOT_CONST); + } + LocalKind::Temp => { + if !self.temp_promotion_state[local].is_promotable() { + self.add(Qualif::NOT_PROMOTABLE); + } + + if let Some(qualif) = self.temp_qualif[local] { + self.add(qualif); + } else { + self.not_const(); + } + } + } + } + fn visit_lvalue(&mut self, lvalue: &Lvalue<'tcx>, context: LvalueContext<'tcx>, location: Location) { match *lvalue { - Lvalue::Local(local) => match self.mir.local_kind(local) { - LocalKind::ReturnPointer => { - self.not_const(); - } - LocalKind::Arg => { - self.add(Qualif::FN_ARGUMENT); - } - LocalKind::Var => { - self.add(Qualif::NOT_CONST); - } - LocalKind::Temp => { - if !self.temp_promotion_state[local].is_promotable() { - self.add(Qualif::NOT_PROMOTABLE); - } - - if let Some(qualif) = self.temp_qualif[local] { - self.add(qualif); - } else { - self.not_const(); - } - } - }, + Lvalue::Local(ref local) => self.visit_local(local, context, location), Lvalue::Static(ref global) => { self.add(Qualif::STATIC); diff --git a/src/librustc_mir/transform/simplify.rs b/src/librustc_mir/transform/simplify.rs index 070250cda4d5d..4b825e585aab9 100644 --- a/src/librustc_mir/transform/simplify.rs +++ b/src/librustc_mir/transform/simplify.rs @@ -352,15 +352,11 @@ struct DeclMarker { } impl<'tcx> Visitor<'tcx> for DeclMarker { - fn visit_lvalue(&mut self, lval: &Lvalue<'tcx>, ctx: LvalueContext<'tcx>, loc: Location) { - if ctx == LvalueContext::StorageLive || ctx == LvalueContext::StorageDead { - // ignore these altogether, they get removed along with their otherwise unused decls. - return; + fn visit_local(&mut self, local: &Local, ctx: LvalueContext<'tcx>, _: Location) { + // ignore these altogether, they get removed along with their otherwise unused decls. + if ctx != LvalueContext::StorageLive && ctx != LvalueContext::StorageDead { + self.locals.insert(local.index()); } - if let Lvalue::Local(ref v) = *lval { - self.locals.insert(v.index()); - } - self.super_lvalue(lval, ctx, loc); } } @@ -384,11 +380,7 @@ impl<'tcx> MutVisitor<'tcx> for LocalUpdater { }); self.super_basic_block_data(block, data); } - fn visit_lvalue(&mut self, lval: &mut Lvalue<'tcx>, ctx: LvalueContext<'tcx>, loc: Location) { - match *lval { - Lvalue::Local(ref mut l) => *l = Local::new(self.map[l.index()]), - _ => (), - }; - self.super_lvalue(lval, ctx, loc); + fn visit_local(&mut self, l: &mut Local, _: LvalueContext<'tcx>, _: Location) { + *l = Local::new(self.map[l.index()]); } } diff --git a/src/librustc_mir/util/def_use.rs b/src/librustc_mir/util/def_use.rs index 8263e149d84e7..bd9fb4bc3cc5f 100644 --- a/src/librustc_mir/util/def_use.rs +++ b/src/librustc_mir/util/def_use.rs @@ -10,7 +10,7 @@ //! Def-use analysis. -use rustc::mir::{Local, Location, Lvalue, Mir}; +use rustc::mir::{Local, Location, Mir}; use rustc::mir::visit::{LvalueContext, MutVisitor, Visitor}; use rustc_data_structures::indexed_vec::IndexVec; use std::marker::PhantomData; @@ -51,7 +51,7 @@ impl<'tcx> DefUseAnalysis<'tcx> { } fn mutate_defs_and_uses(&self, local: Local, mir: &mut Mir<'tcx>, mut callback: F) - where F: for<'a> FnMut(&'a mut Lvalue<'tcx>, + where F: for<'a> FnMut(&'a mut Local, LvalueContext<'tcx>, Location) { for lvalue_use in &self.info[local].defs_and_uses { @@ -65,8 +65,8 @@ impl<'tcx> DefUseAnalysis<'tcx> { pub fn replace_all_defs_and_uses_with(&self, local: Local, mir: &mut Mir<'tcx>, - new_lvalue: Lvalue<'tcx>) { - self.mutate_defs_and_uses(local, mir, |lvalue, _, _| *lvalue = new_lvalue.clone()) + new_local: Local) { + self.mutate_defs_and_uses(local, mir, |local, _, _| *local = new_local) } } @@ -74,30 +74,15 @@ struct DefUseFinder<'tcx> { info: IndexVec>, } -impl<'tcx> DefUseFinder<'tcx> { - fn lvalue_mut_info(&mut self, lvalue: &Lvalue<'tcx>) -> Option<&mut Info<'tcx>> { - let info = &mut self.info; - - if let Lvalue::Local(local) = *lvalue { - Some(&mut info[local]) - } else { - None - } - } -} - impl<'tcx> Visitor<'tcx> for DefUseFinder<'tcx> { - fn visit_lvalue(&mut self, - lvalue: &Lvalue<'tcx>, - context: LvalueContext<'tcx>, - location: Location) { - if let Some(ref mut info) = self.lvalue_mut_info(lvalue) { - info.defs_and_uses.push(Use { - context, - location, - }) - } - self.super_lvalue(lvalue, context, location) + fn visit_local(&mut self, + &local: &Local, + context: LvalueContext<'tcx>, + location: Location) { + self.info[local].defs_and_uses.push(Use { + context, + location, + }); } } @@ -134,7 +119,7 @@ struct MutateUseVisitor<'tcx, F> { impl<'tcx, F> MutateUseVisitor<'tcx, F> { fn new(query: Local, callback: F, _: &Mir<'tcx>) -> MutateUseVisitor<'tcx, F> - where F: for<'a> FnMut(&'a mut Lvalue<'tcx>, LvalueContext<'tcx>, Location) { + where F: for<'a> FnMut(&'a mut Local, LvalueContext<'tcx>, Location) { MutateUseVisitor { query, callback, @@ -144,16 +129,13 @@ impl<'tcx, F> MutateUseVisitor<'tcx, F> { } impl<'tcx, F> MutVisitor<'tcx> for MutateUseVisitor<'tcx, F> - where F: for<'a> FnMut(&'a mut Lvalue<'tcx>, LvalueContext<'tcx>, Location) { - fn visit_lvalue(&mut self, - lvalue: &mut Lvalue<'tcx>, + where F: for<'a> FnMut(&'a mut Local, LvalueContext<'tcx>, Location) { + fn visit_local(&mut self, + local: &mut Local, context: LvalueContext<'tcx>, location: Location) { - if let Lvalue::Local(local) = *lvalue { - if local == self.query { - (self.callback)(lvalue, context, location) - } + if *local == self.query { + (self.callback)(local, context, location) } - self.super_lvalue(lvalue, context, location) } } diff --git a/src/librustc_mir/util/liveness.rs b/src/librustc_mir/util/liveness.rs index fd15c90dc9013..e6d3a82ff9b53 100644 --- a/src/librustc_mir/util/liveness.rs +++ b/src/librustc_mir/util/liveness.rs @@ -60,49 +60,45 @@ struct BlockInfoVisitor { } impl<'tcx> Visitor<'tcx> for BlockInfoVisitor { - fn visit_lvalue(&mut self, - lvalue: &Lvalue<'tcx>, - context: LvalueContext<'tcx>, - location: Location) { - if let Lvalue::Local(local) = *lvalue { - match context { - LvalueContext::Store | - - // We let Call defined the result in both the success and unwind cases. - // This may not be right. - LvalueContext::Call | - - // Storage live and storage dead aren't proper defines, but we can ignore - // values that come before them. - LvalueContext::StorageLive | - LvalueContext::StorageDead => { - self.defs.add(&local); - } - LvalueContext::Projection(..) | - - // Borrows only consider their local used at the point of the borrow. - // This won't affect the results since we use this analysis for generators - // and we only care about the result at suspension points. Borrows cannot - // cross suspension points so this behavior is unproblematic. - LvalueContext::Borrow { .. } | - - LvalueContext::Inspect | - LvalueContext::Consume | - LvalueContext::Validate | - - // We consider drops to always be uses of locals. - // Drop eloboration should be run before this analysis otherwise - // the results might be too pessimistic. - LvalueContext::Drop => { - // Ignore uses which are already defined in this block - if !self.pre_defs.contains(&local) { - self.uses.add(&local); - } + fn visit_local(&mut self, + &local: &Local, + context: LvalueContext<'tcx>, + _: Location) { + match context { + LvalueContext::Store | + + // We let Call defined the result in both the success and unwind cases. + // This may not be right. + LvalueContext::Call | + + // Storage live and storage dead aren't proper defines, but we can ignore + // values that come before them. + LvalueContext::StorageLive | + LvalueContext::StorageDead => { + self.defs.add(&local); + } + LvalueContext::Projection(..) | + + // Borrows only consider their local used at the point of the borrow. + // This won't affect the results since we use this analysis for generators + // and we only care about the result at suspension points. Borrows cannot + // cross suspension points so this behavior is unproblematic. + LvalueContext::Borrow { .. } | + + LvalueContext::Inspect | + LvalueContext::Consume | + LvalueContext::Validate | + + // We consider drops to always be uses of locals. + // Drop eloboration should be run before this analysis otherwise + // the results might be too pessimistic. + LvalueContext::Drop => { + // Ignore uses which are already defined in this block + if !self.pre_defs.contains(&local) { + self.uses.add(&local); } } } - - self.super_lvalue(lvalue, context, location) } } diff --git a/src/librustc_trans/mir/analyze.rs b/src/librustc_trans/mir/analyze.rs index a17ddabb1a7cd..95b76d32bf848 100644 --- a/src/librustc_trans/mir/analyze.rs +++ b/src/librustc_trans/mir/analyze.rs @@ -134,60 +134,61 @@ impl<'mir, 'a, 'tcx> Visitor<'tcx> for LocalAnalyzer<'mir, 'a, 'tcx> { location: Location) { debug!("visit_lvalue(lvalue={:?}, context={:?})", lvalue, context); - // Allow uses of projections of immediate pair fields. if let mir::Lvalue::Projection(ref proj) = *lvalue { - if let mir::Lvalue::Local(_) = proj.base { - let ty = proj.base.ty(self.cx.mir, self.cx.ccx.tcx()); - - let ty = self.cx.monomorphize(&ty.to_ty(self.cx.ccx.tcx())); - if common::type_is_imm_pair(self.cx.ccx, ty) { + // Allow uses of projections of immediate pair fields. + if let LvalueContext::Consume = context { + if let mir::Lvalue::Local(_) = proj.base { if let mir::ProjectionElem::Field(..) = proj.elem { - if let LvalueContext::Consume = context { + let ty = proj.base.ty(self.cx.mir, self.cx.ccx.tcx()); + + let ty = self.cx.monomorphize(&ty.to_ty(self.cx.ccx.tcx())); + if common::type_is_imm_pair(self.cx.ccx, ty) { return; } } } } - } - if let mir::Lvalue::Local(index) = *lvalue { - match context { - LvalueContext::Call => { - self.mark_assigned(index); - } + // A deref projection only reads the pointer, never needs the lvalue. + if let mir::ProjectionElem::Deref = proj.elem { + return self.visit_lvalue(&proj.base, LvalueContext::Consume, location); + } + } - LvalueContext::StorageLive | - LvalueContext::StorageDead | - LvalueContext::Validate | - LvalueContext::Inspect | - LvalueContext::Consume => {} + self.super_lvalue(lvalue, context, location); + } - LvalueContext::Store | - LvalueContext::Borrow { .. } | - LvalueContext::Projection(..) => { - self.mark_as_lvalue(index); - } + fn visit_local(&mut self, + &index: &mir::Local, + context: LvalueContext<'tcx>, + _: Location) { + match context { + LvalueContext::Call => { + self.mark_assigned(index); + } - LvalueContext::Drop => { - let ty = lvalue.ty(self.cx.mir, self.cx.ccx.tcx()); - let ty = self.cx.monomorphize(&ty.to_ty(self.cx.ccx.tcx())); + LvalueContext::StorageLive | + LvalueContext::StorageDead | + LvalueContext::Validate | + LvalueContext::Inspect | + LvalueContext::Consume => {} - // Only need the lvalue if we're actually dropping it. - if self.cx.ccx.shared().type_needs_drop(ty) { - self.mark_as_lvalue(index); - } - } + LvalueContext::Store | + LvalueContext::Borrow { .. } | + LvalueContext::Projection(..) => { + self.mark_as_lvalue(index); } - } - // A deref projection only reads the pointer, never needs the lvalue. - if let mir::Lvalue::Projection(ref proj) = *lvalue { - if let mir::ProjectionElem::Deref = proj.elem { - return self.visit_lvalue(&proj.base, LvalueContext::Consume, location); + LvalueContext::Drop => { + let ty = mir::Lvalue::Local(index).ty(self.cx.mir, self.cx.ccx.tcx()); + let ty = self.cx.monomorphize(&ty.to_ty(self.cx.ccx.tcx())); + + // Only need the lvalue if we're actually dropping it. + if self.cx.ccx.shared().type_needs_drop(ty) { + self.mark_as_lvalue(index); + } } } - - self.super_lvalue(lvalue, context, location); } }