diff --git a/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs b/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs index 13f898219bc12..a71d23e7e1e7e 100644 --- a/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs +++ b/src/librustc_borrowck/borrowck/mir/elaborate_drops.rs @@ -161,6 +161,7 @@ impl<'b, 'tcx> ElaborateDropsCtxt<'b, 'tcx> { fn create_drop_flag(&mut self, index: MovePathIndex) { let tcx = self.tcx; let patch = &mut self.patch; + debug!("create_drop_flag({:?})", self.mir.span); self.drop_flags.entry(index).or_insert_with(|| { patch.new_temp(tcx.types.bool) }); diff --git a/src/librustc_mir/build/block.rs b/src/librustc_mir/build/block.rs index 121d592da0316..3305cfc0dfe1a 100644 --- a/src/librustc_mir/build/block.rs +++ b/src/librustc_mir/build/block.rs @@ -67,7 +67,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { this.expr_into_pattern(block, pattern, init) })); } else { - this.storage_live_for_bindings(block, &pattern); + this.visit_bindings(&pattern, &mut |this, _, _, node, span, _| { + this.storage_live_binding(block, node, span); + this.schedule_drop_for_binding(node, span); + }) } // Enter the visibility scope, after evaluating the initializer. diff --git a/src/librustc_mir/build/expr/as_lvalue.rs b/src/librustc_mir/build/expr/as_lvalue.rs index 5abfe084f2258..8886a310429ea 100644 --- a/src/librustc_mir/build/expr/as_lvalue.rs +++ b/src/librustc_mir/build/expr/as_lvalue.rs @@ -56,8 +56,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { let (usize_ty, bool_ty) = (this.hir.usize_ty(), this.hir.bool_ty()); let slice = unpack!(block = this.as_lvalue(block, lhs)); - - let idx = unpack!(block = this.as_operand(block, index)); + // extent=None so lvalue indexes live forever. They are scalars so they + // do not need storage annotations, and they are often copied between + // places. + let idx = unpack!(block = this.as_operand(block, None, index)); // bounds check: let (len, lt) = (this.temp(usize_ty.clone()), this.temp(bool_ty)); @@ -121,7 +123,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { Some(Category::Lvalue) => false, _ => true, }); - this.as_temp(block, expr) + this.as_temp(block, expr.temp_lifetime, expr) } } } diff --git a/src/librustc_mir/build/expr/as_operand.rs b/src/librustc_mir/build/expr/as_operand.rs index 09cdcc74ef63e..8d79e755685d0 100644 --- a/src/librustc_mir/build/expr/as_operand.rs +++ b/src/librustc_mir/build/expr/as_operand.rs @@ -13,29 +13,52 @@ use build::{BlockAnd, BlockAndExtension, Builder}; use build::expr::category::Category; use hair::*; +use rustc::middle::region::CodeExtent; use rustc::mir::*; impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { + /// Returns an operand suitable for use until the end of the current + /// scope expression. + /// + /// The operand returned from this function will *not be valid* after + /// an ExprKind::Scope is passed, so please do *not* return it from + /// functions to avoid bad miscompiles. + pub fn as_local_operand(&mut self, block: BasicBlock, expr: M) + -> BlockAnd> + where M: Mirror<'tcx, Output = Expr<'tcx>> + { + let topmost_scope = self.topmost_scope(); // FIXME(#6393) + self.as_operand(block, Some(topmost_scope), expr) + } + /// Compile `expr` into a value that can be used as an operand. /// If `expr` is an lvalue like `x`, this will introduce a /// temporary `tmp = x`, so that we capture the value of `x` at /// this time. - pub fn as_operand(&mut self, block: BasicBlock, expr: M) -> BlockAnd> + /// + /// The operand is known to be live until the end of `scope`. + pub fn as_operand(&mut self, + block: BasicBlock, + scope: Option, + expr: M) -> BlockAnd> where M: Mirror<'tcx, Output = Expr<'tcx>> { let expr = self.hir.mirror(expr); - self.expr_as_operand(block, expr) + self.expr_as_operand(block, scope, expr) } fn expr_as_operand(&mut self, mut block: BasicBlock, + scope: Option, expr: Expr<'tcx>) -> BlockAnd> { debug!("expr_as_operand(block={:?}, expr={:?})", block, expr); let this = self; if let ExprKind::Scope { extent, value } = expr.kind { - return this.in_scope(extent, block, |this| this.as_operand(block, value)); + return this.in_scope(extent, block, |this| { + this.as_operand(block, scope, value) + }); } let category = Category::of(&expr.kind).unwrap(); @@ -47,7 +70,8 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { } Category::Lvalue | Category::Rvalue(..) => { - let operand = unpack!(block = this.as_temp(block, expr)); + let operand = + unpack!(block = this.as_temp(block, scope, expr)); block.and(Operand::Consume(operand)) } } diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs index 7f5d9c36ecedf..961713bcfe6d5 100644 --- a/src/librustc_mir/build/expr/as_rvalue.rs +++ b/src/librustc_mir/build/expr/as_rvalue.rs @@ -21,22 +21,34 @@ use build::expr::category::{Category, RvalueFunc}; use hair::*; use rustc_const_math::{ConstInt, ConstIsize}; use rustc::middle::const_val::ConstVal; +use rustc::middle::region::CodeExtent; use rustc::ty; use rustc::mir::*; use syntax::ast; use syntax_pos::Span; impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { + /// See comment on `as_local_operand` + pub fn as_local_rvalue(&mut self, block: BasicBlock, expr: M) + -> BlockAnd> + where M: Mirror<'tcx, Output = Expr<'tcx>> + { + let topmost_scope = self.topmost_scope(); // FIXME(#6393) + self.as_rvalue(block, Some(topmost_scope), expr) + } + /// Compile `expr`, yielding an rvalue. - pub fn as_rvalue(&mut self, block: BasicBlock, expr: M) -> BlockAnd> + pub fn as_rvalue(&mut self, block: BasicBlock, scope: Option, expr: M) + -> BlockAnd> where M: Mirror<'tcx, Output = Expr<'tcx>> { let expr = self.hir.mirror(expr); - self.expr_as_rvalue(block, expr) + self.expr_as_rvalue(block, scope, expr) } fn expr_as_rvalue(&mut self, mut block: BasicBlock, + scope: Option, expr: Expr<'tcx>) -> BlockAnd> { debug!("expr_as_rvalue(block={:?}, expr={:?})", block, expr); @@ -47,10 +59,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { match expr.kind { ExprKind::Scope { extent, value } => { - this.in_scope(extent, block, |this| this.as_rvalue(block, value)) + this.in_scope(extent, block, |this| this.as_rvalue(block, scope, value)) } ExprKind::Repeat { value, count } => { - let value_operand = unpack!(block = this.as_operand(block, value)); + let value_operand = unpack!(block = this.as_operand(block, scope, value)); block.and(Rvalue::Repeat(value_operand, count)) } ExprKind::Borrow { region, borrow_kind, arg } => { @@ -58,13 +70,13 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { block.and(Rvalue::Ref(region, borrow_kind, arg_lvalue)) } ExprKind::Binary { op, lhs, rhs } => { - let lhs = unpack!(block = this.as_operand(block, lhs)); - let rhs = unpack!(block = this.as_operand(block, rhs)); + let lhs = unpack!(block = this.as_operand(block, scope, lhs)); + let rhs = unpack!(block = this.as_operand(block, scope, rhs)); this.build_binary_op(block, op, expr_span, expr.ty, lhs, rhs) } ExprKind::Unary { op, arg } => { - let arg = unpack!(block = this.as_operand(block, arg)); + let arg = unpack!(block = this.as_operand(block, scope, arg)); // Check for -MIN on signed integers if this.hir.check_overflow() && op == UnOp::Neg && expr.ty.is_signed() { let bool_ty = this.hir.bool_ty(); @@ -97,27 +109,27 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { ExprKind::Cast { source } => { let source = this.hir.mirror(source); - let source = unpack!(block = this.as_operand(block, source)); + let source = unpack!(block = this.as_operand(block, scope, source)); block.and(Rvalue::Cast(CastKind::Misc, source, expr.ty)) } ExprKind::Use { source } => { - let source = unpack!(block = this.as_operand(block, source)); + let source = unpack!(block = this.as_operand(block, scope, source)); block.and(Rvalue::Use(source)) } ExprKind::ReifyFnPointer { source } => { - let source = unpack!(block = this.as_operand(block, source)); + let source = unpack!(block = this.as_operand(block, scope, source)); block.and(Rvalue::Cast(CastKind::ReifyFnPointer, source, expr.ty)) } ExprKind::UnsafeFnPointer { source } => { - let source = unpack!(block = this.as_operand(block, source)); + let source = unpack!(block = this.as_operand(block, scope, source)); block.and(Rvalue::Cast(CastKind::UnsafeFnPointer, source, expr.ty)) } ExprKind::ClosureFnPointer { source } => { - let source = unpack!(block = this.as_operand(block, source)); + let source = unpack!(block = this.as_operand(block, scope, source)); block.and(Rvalue::Cast(CastKind::ClosureFnPointer, source, expr.ty)) } ExprKind::Unsize { source } => { - let source = unpack!(block = this.as_operand(block, source)); + let source = unpack!(block = this.as_operand(block, scope, source)); block.and(Rvalue::Cast(CastKind::Unsize, source, expr.ty)) } ExprKind::Array { fields } => { @@ -150,7 +162,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { // first process the set of fields let fields: Vec<_> = fields.into_iter() - .map(|f| unpack!(block = this.as_operand(block, f))) + .map(|f| unpack!(block = this.as_operand(block, scope, f))) .collect(); block.and(Rvalue::Aggregate(AggregateKind::Array, fields)) @@ -159,7 +171,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { // first process the set of fields let fields: Vec<_> = fields.into_iter() - .map(|f| unpack!(block = this.as_operand(block, f))) + .map(|f| unpack!(block = this.as_operand(block, scope, f))) .collect(); block.and(Rvalue::Aggregate(AggregateKind::Tuple, fields)) @@ -167,7 +179,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { ExprKind::Closure { closure_id, substs, upvars } => { // see (*) above let upvars = upvars.into_iter() - .map(|upvar| unpack!(block = this.as_operand(block, upvar))) + .map(|upvar| unpack!(block = this.as_operand(block, scope, upvar))) .collect(); block.and(Rvalue::Aggregate(AggregateKind::Closure(closure_id, substs), upvars)) } @@ -179,10 +191,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { // first process the set of fields that were provided // (evaluating them in order given by user) - let fields_map: FxHashMap<_, _> = - fields.into_iter() - .map(|f| (f.name, unpack!(block = this.as_operand(block, f.expr)))) - .collect(); + let fields_map: FxHashMap<_, _> = fields.into_iter() + .map(|f| (f.name, unpack!(block = this.as_operand(block, scope, f.expr)))) + .collect(); let field_names = this.hir.all_fields(adt_def, variant_index); @@ -235,7 +246,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { Some(Category::Rvalue(RvalueFunc::AsRvalue)) => false, _ => true, }); - let operand = unpack!(block = this.as_operand(block, expr)); + let operand = unpack!(block = this.as_operand(block, scope, expr)); block.and(Rvalue::Use(operand)) } } diff --git a/src/librustc_mir/build/expr/as_temp.rs b/src/librustc_mir/build/expr/as_temp.rs index 0ae4bcc4205d4..69b9570200921 100644 --- a/src/librustc_mir/build/expr/as_temp.rs +++ b/src/librustc_mir/build/expr/as_temp.rs @@ -13,29 +13,38 @@ use build::{BlockAnd, BlockAndExtension, Builder}; use build::expr::category::Category; use hair::*; +use rustc::middle::region::CodeExtent; use rustc::mir::*; impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { /// Compile `expr` into a fresh temporary. This is used when building /// up rvalues so as to freeze the value that will be consumed. - pub fn as_temp(&mut self, block: BasicBlock, expr: M) -> BlockAnd> + pub fn as_temp(&mut self, + block: BasicBlock, + temp_lifetime: Option, + expr: M) + -> BlockAnd> where M: Mirror<'tcx, Output = Expr<'tcx>> { let expr = self.hir.mirror(expr); - self.expr_as_temp(block, expr) + self.expr_as_temp(block, temp_lifetime, expr) } - fn expr_as_temp(&mut self, mut block: BasicBlock, expr: Expr<'tcx>) -> BlockAnd> { + fn expr_as_temp(&mut self, + mut block: BasicBlock, + temp_lifetime: Option, + expr: Expr<'tcx>) + -> BlockAnd> { debug!("expr_as_temp(block={:?}, expr={:?})", block, expr); let this = self; - if let ExprKind::Scope { extent, value } = expr.kind { - return this.in_scope(extent, block, |this| this.as_temp(block, value)); + if let ExprKind::Scope { .. } = expr.kind { + span_bug!(expr.span, "unexpected scope expression in as_temp: {:?}", + expr); } let expr_ty = expr.ty.clone(); let temp = this.temp(expr_ty.clone()); - let temp_lifetime = expr.temp_lifetime; let expr_span = expr.span; let source_info = this.source_info(expr_span); diff --git a/src/librustc_mir/build/expr/into.rs b/src/librustc_mir/build/expr/into.rs index ae51951b519bd..dab8510687329 100644 --- a/src/librustc_mir/build/expr/into.rs +++ b/src/librustc_mir/build/expr/into.rs @@ -52,7 +52,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { _ => false, }; - unpack!(block = this.as_rvalue(block, source)); + unpack!(block = this.as_local_rvalue(block, source)); // This is an optimization. If the expression was a call then we already have an // unreachable block. Don't bother to terminate it and create a new one. @@ -65,7 +65,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { } } ExprKind::If { condition: cond_expr, then: then_expr, otherwise: else_expr } => { - let operand = unpack!(block = this.as_operand(block, cond_expr)); + let operand = unpack!(block = this.as_local_operand(block, cond_expr)); let mut then_block = this.cfg.start_new_block(); let mut else_block = this.cfg.start_new_block(); @@ -107,7 +107,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { (this.cfg.start_new_block(), this.cfg.start_new_block(), this.cfg.start_new_block(), this.cfg.start_new_block()); - let lhs = unpack!(block = this.as_operand(block, lhs)); + let lhs = unpack!(block = this.as_local_operand(block, lhs)); let blocks = match op { LogicalOp::And => (else_block, false_block), LogicalOp::Or => (true_block, else_block), @@ -115,7 +115,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { let term = TerminatorKind::if_(this.hir.tcx(), lhs, blocks.0, blocks.1); this.cfg.terminate(block, source_info, term); - let rhs = unpack!(else_block = this.as_operand(else_block, rhs)); + let rhs = unpack!(else_block = this.as_local_operand(else_block, rhs)); let term = TerminatorKind::if_(this.hir.tcx(), rhs, true_block, false_block); this.cfg.terminate(else_block, source_info, term); @@ -173,7 +173,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { if let Some(cond_expr) = opt_cond_expr { let loop_block_end; let cond = unpack!( - loop_block_end = this.as_operand(loop_block, cond_expr)); + loop_block_end = this.as_local_operand(loop_block, cond_expr)); body_block = this.cfg.start_new_block(); let term = TerminatorKind::if_(this.hir.tcx(), cond, body_block, exit_block); @@ -206,10 +206,10 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { } _ => false }; - let fun = unpack!(block = this.as_operand(block, fun)); + let fun = unpack!(block = this.as_local_operand(block, fun)); let args: Vec<_> = args.into_iter() - .map(|arg| unpack!(block = this.as_operand(block, arg))) + .map(|arg| unpack!(block = this.as_local_operand(block, arg))) .collect(); let success = this.cfg.start_new_block(); @@ -265,7 +265,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { _ => true, }); - let rvalue = unpack!(block = this.as_rvalue(block, expr)); + let rvalue = unpack!(block = this.as_local_rvalue(block, expr)); this.cfg.push_assign(block, source_info, destination, rvalue); block.unit() } diff --git a/src/librustc_mir/build/expr/stmt.rs b/src/librustc_mir/build/expr/stmt.rs index c577aab40dbeb..be39dcbf6d08d 100644 --- a/src/librustc_mir/build/expr/stmt.rs +++ b/src/librustc_mir/build/expr/stmt.rs @@ -38,14 +38,14 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { // Generate better code for things that don't need to be // dropped. if this.hir.needs_drop(lhs.ty) { - let rhs = unpack!(block = this.as_operand(block, rhs)); + let rhs = unpack!(block = this.as_local_operand(block, rhs)); let lhs = unpack!(block = this.as_lvalue(block, lhs)); unpack!(block = this.build_drop_and_replace( block, lhs_span, lhs, rhs )); block.unit() } else { - let rhs = unpack!(block = this.as_rvalue(block, rhs)); + let rhs = unpack!(block = this.as_local_rvalue(block, rhs)); let lhs = unpack!(block = this.as_lvalue(block, lhs)); this.cfg.push_assign(block, source_info, &lhs, rhs); block.unit() @@ -64,7 +64,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { let lhs_ty = lhs.ty; // As above, RTL. - let rhs = unpack!(block = this.as_operand(block, rhs)); + let rhs = unpack!(block = this.as_local_operand(block, rhs)); let lhs = unpack!(block = this.as_lvalue(block, lhs)); // we don't have to drop prior contents or anything @@ -122,7 +122,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { unpack!(block = this.as_lvalue(block, output)) }).collect(); let inputs = inputs.into_iter().map(|input| { - unpack!(block = this.as_operand(block, input)) + unpack!(block = this.as_local_operand(block, input)) }).collect(); this.cfg.push(block, Statement { source_info: source_info, diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs index 6b6acb054b1b0..705eb1f56608e 100644 --- a/src/librustc_mir/build/matches/mod.rs +++ b/src/librustc_mir/build/matches/mod.rs @@ -123,16 +123,16 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { PatternKind::Binding { mode: BindingMode::ByValue, var, subpattern: None, .. } => { - self.storage_live_for_bindings(block, &irrefutable_pat); - let lvalue = Lvalue::Local(self.var_indices[&var]); - return self.into(&lvalue, block, initializer); + let lvalue = self.storage_live_binding(block, var, irrefutable_pat.span); + unpack!(block = self.into(&lvalue, block, initializer)); + self.schedule_drop_for_binding(var, irrefutable_pat.span); + block.unit() + } + _ => { + let lvalue = unpack!(block = self.as_lvalue(block, initializer)); + self.lvalue_into_pattern(block, irrefutable_pat, &lvalue) } - _ => {} } - let lvalue = unpack!(block = self.as_lvalue(block, initializer)); - self.lvalue_into_pattern(block, - irrefutable_pat, - &lvalue) } pub fn lvalue_into_pattern(&mut self, @@ -174,79 +174,70 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { scope_span: Span, pattern: &Pattern<'tcx>) -> Option { - match *pattern.kind { - PatternKind::Binding { mutability, name, mode: _, var, ty, ref subpattern } => { - if var_scope.is_none() { - var_scope = Some(self.new_visibility_scope(scope_span)); - } - let source_info = SourceInfo { - span: pattern.span, - scope: var_scope.unwrap() - }; - self.declare_binding(source_info, mutability, name, var, ty); - if let Some(subpattern) = subpattern.as_ref() { - var_scope = self.declare_bindings(var_scope, scope_span, subpattern); - } - } - PatternKind::Array { ref prefix, ref slice, ref suffix } | - PatternKind::Slice { ref prefix, ref slice, ref suffix } => { - for subpattern in prefix.iter().chain(slice).chain(suffix) { - var_scope = self.declare_bindings(var_scope, scope_span, subpattern); - } - } - PatternKind::Constant { .. } | PatternKind::Range { .. } | PatternKind::Wild => { - } - PatternKind::Deref { ref subpattern } => { - var_scope = self.declare_bindings(var_scope, scope_span, subpattern); - } - PatternKind::Leaf { ref subpatterns } | - PatternKind::Variant { ref subpatterns, .. } => { - for subpattern in subpatterns { - var_scope = self.declare_bindings(var_scope, scope_span, &subpattern.pattern); - } + self.visit_bindings(pattern, &mut |this, mutability, name, var, span, ty| { + if var_scope.is_none() { + var_scope = Some(this.new_visibility_scope(scope_span)); } - } + let source_info = SourceInfo { + span: span, + scope: var_scope.unwrap() + }; + this.declare_binding(source_info, mutability, name, var, ty); + }); var_scope } - /// Emit `StorageLive` for every binding in the pattern. - pub fn storage_live_for_bindings(&mut self, - block: BasicBlock, - pattern: &Pattern<'tcx>) { - match *pattern.kind { - PatternKind::Binding { var, ref subpattern, .. } => { - let lvalue = Lvalue::Local(self.var_indices[&var]); - let source_info = self.source_info(pattern.span); - self.cfg.push(block, Statement { - source_info: source_info, - kind: StatementKind::StorageLive(lvalue) - }); + pub fn storage_live_binding(&mut self, block: BasicBlock, var: NodeId, span: Span) + -> Lvalue<'tcx> + { + let local_id = self.var_indices[&var]; + let source_info = self.source_info(span); + self.cfg.push(block, Statement { + source_info: source_info, + kind: StatementKind::StorageLive(Lvalue::Local(local_id)) + }); + Lvalue::Local(local_id) + } + pub fn schedule_drop_for_binding(&mut self, var: NodeId, span: Span) { + let local_id = self.var_indices[&var]; + let var_ty = self.local_decls[local_id].ty; + let extent = self.hir.tcx().region_maps.var_scope(var); + self.schedule_drop(span, extent, &Lvalue::Local(local_id), var_ty); + } + + pub fn visit_bindings(&mut self, pattern: &Pattern<'tcx>, mut f: &mut F) + where F: FnMut(&mut Self, Mutability, Name, NodeId, Span, Ty<'tcx>) + { + match *pattern.kind { + PatternKind::Binding { mutability, name, var, ty, ref subpattern, .. } => { + f(self, mutability, name, var, pattern.span, ty); if let Some(subpattern) = subpattern.as_ref() { - self.storage_live_for_bindings(block, subpattern); + self.visit_bindings(subpattern, f); } } PatternKind::Array { ref prefix, ref slice, ref suffix } | PatternKind::Slice { ref prefix, ref slice, ref suffix } => { for subpattern in prefix.iter().chain(slice).chain(suffix) { - self.storage_live_for_bindings(block, subpattern); + self.visit_bindings(subpattern, f); } } PatternKind::Constant { .. } | PatternKind::Range { .. } | PatternKind::Wild => { } PatternKind::Deref { ref subpattern } => { - self.storage_live_for_bindings(block, subpattern); + self.visit_bindings(subpattern, f); } PatternKind::Leaf { ref subpatterns } | PatternKind::Variant { ref subpatterns, .. } => { for subpattern in subpatterns { - self.storage_live_for_bindings(block, &subpattern.pattern); + self.visit_bindings(&subpattern.pattern, f); } } } } } + /// List of blocks for each arm (and potentially other metadata in the /// future). struct ArmBlocks { @@ -670,7 +661,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { // guard, this block is simply unreachable let guard = self.hir.mirror(guard); let source_info = self.source_info(guard.span); - let cond = unpack!(block = self.as_operand(block, guard)); + let cond = unpack!(block = self.as_local_operand(block, guard)); let otherwise = self.cfg.start_new_block(); self.cfg.terminate(block, source_info, TerminatorKind::if_(self.hir.tcx(), cond, arm_block, otherwise)); @@ -691,25 +682,16 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { // Assign each of the bindings. This may trigger moves out of the candidate. for binding in bindings { - // Find the variable for the `var_id` being bound. It - // should have been created by a previous call to - // `declare_bindings`. - let var_index = self.var_indices[&binding.var_id]; - + let source_info = self.source_info(binding.span); + let local = self.storage_live_binding(block, binding.var_id, binding.span); + self.schedule_drop_for_binding(binding.var_id, binding.span); let rvalue = match binding.binding_mode { BindingMode::ByValue => Rvalue::Use(Operand::Consume(binding.source)), BindingMode::ByRef(region, borrow_kind) => Rvalue::Ref(region, borrow_kind, binding.source), }; - - let source_info = self.source_info(binding.span); - self.cfg.push(block, Statement { - source_info: source_info, - kind: StatementKind::StorageLive(Lvalue::Local(var_index)) - }); - self.cfg.push_assign(block, source_info, - &Lvalue::Local(var_index), rvalue); + self.cfg.push_assign(block, source_info, &local, rvalue); } } @@ -730,8 +712,6 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { name: Some(name), source_info: Some(source_info), }); - let extent = self.hir.tcx().region_maps.var_scope(var_id); - self.schedule_drop(source_info.span, extent, &Lvalue::Local(var), var_ty); self.var_indices.insert(var_id, var); debug!("declare_binding: var={:?}", var); diff --git a/src/librustc_mir/build/scope.rs b/src/librustc_mir/build/scope.rs index 282361fc13e27..3dab1717f6b2e 100644 --- a/src/librustc_mir/build/scope.rs +++ b/src/librustc_mir/build/scope.rs @@ -253,9 +253,9 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { f: F) where F: FnOnce(&mut Builder<'a, 'gcx, 'tcx>) { - let extent = self.scopes.last().map(|scope| scope.extent).unwrap(); + let extent = self.topmost_scope(); let loop_scope = LoopScope { - extent: extent.clone(), + extent: extent, continue_block: loop_block, break_block: break_block, break_destination: break_destination, @@ -416,6 +416,12 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> { self.scopes[1].extent } + /// Returns the topmost active scope, which is known to be alive until + /// the next scope expression. + pub fn topmost_scope(&self) -> CodeExtent { + self.scopes.last().expect("topmost_scope: no scopes present").extent + } + // Scheduling drops // ================ /// Indicates that `lvalue` should be dropped on exit from diff --git a/src/test/codegen/lifetime_start_end.rs b/src/test/codegen/lifetime_start_end.rs index e3b35cf355250..5c1f1f8f2bb20 100644 --- a/src/test/codegen/lifetime_start_end.rs +++ b/src/test/codegen/lifetime_start_end.rs @@ -11,11 +11,9 @@ // compile-flags: -O -C no-prepopulate-passes #![crate_type = "lib"] -#![feature(rustc_attrs)] // CHECK-LABEL: @test #[no_mangle] -#[rustc_mir] // FIXME #27840 MIR has different codegen. pub fn test() { let a = 0; &a; // keep variable in an alloca @@ -33,11 +31,11 @@ pub fn test() { // CHECK: [[S__5:%[0-9]+]] = bitcast %"core::option::Option"* %_5 to i8* // CHECK: call void @llvm.lifetime.start(i{{[0-9 ]+}}, i8* [[S__5]]) -// CHECK: [[E__5:%[0-9]+]] = bitcast %"core::option::Option"* %_5 to i8* -// CHECK: call void @llvm.lifetime.end(i{{[0-9 ]+}}, i8* [[E__5]]) - // CHECK: [[E_b:%[0-9]+]] = bitcast %"core::option::Option"** %b to i8* // CHECK: call void @llvm.lifetime.end(i{{[0-9 ]+}}, i8* [[E_b]]) + +// CHECK: [[E__5:%[0-9]+]] = bitcast %"core::option::Option"* %_5 to i8* +// CHECK: call void @llvm.lifetime.end(i{{[0-9 ]+}}, i8* [[E__5]]) } let c = 1; diff --git a/src/test/debuginfo/drop-locations.rs b/src/test/debuginfo/drop-locations.rs index 3a7c534c13902..b4f6b33be26a1 100644 --- a/src/test/debuginfo/drop-locations.rs +++ b/src/test/debuginfo/drop-locations.rs @@ -14,7 +14,8 @@ #![allow(unused)] -// compile-flags:-g +// compile-flags:-g -O -C no-prepopulate-passes +// -O -C no-prepopulate-passes added to work around https://bugs.llvm.org/show_bug.cgi?id=32123 // This test checks that drop glue code gets attributed to scope's closing brace, // and function epilogues - to function's closing brace. diff --git a/src/test/mir-opt/basic_assignment.rs b/src/test/mir-opt/basic_assignment.rs new file mode 100644 index 0000000000000..9c924a23903f9 --- /dev/null +++ b/src/test/mir-opt/basic_assignment.rs @@ -0,0 +1,85 @@ +// Copyright 2017 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// this tests move up progration, which is not yet implemented +// Copyright 2017 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// check that codegen of assignment expressions is sane. Assignments +// tend to be absent in simple code, so subtle breakage in them can +// leave a quite hard-to-find trail of destruction. + +fn main() { + let nodrop_x = false; + let nodrop_y; + + nodrop_y = nodrop_x; + + let drop_x : Option> = None; + let drop_y; + + drop_y = drop_x; +} + +// END RUST SOURCE +// START rustc.node4.SimplifyCfg.initial-after.mir +// bb0: { +// StorageLive(_1); +// _1 = const false; +// StorageLive(_2); +// StorageLive(_3); +// _3 = _1; +// _2 = _3; +// StorageDead(_3); +// StorageLive(_4); +// _4 = std::option::Option>::None; +// StorageLive(_6); +// StorageLive(_7); +// _7 = _4; +// replace(_6 <- _7) -> [return: bb5, unwind: bb4]; +// } +// bb1: { +// resume; +// } +// bb2: { +// drop(_4) -> bb1; +// } +// bb3: { +// drop(_6) -> bb2; +// } +// bb4: { +// drop(_7) -> bb3; +// } +// bb5: { +// drop(_7) -> [return: bb6, unwind: bb3]; +// } +// bb6: { +// StorageDead(_7); +// _0 = (); +// drop(_6) -> [return: bb7, unwind: bb2]; +// } +// bb7: { +// StorageDead(_6); +// drop(_4) -> bb8; +// } +// bb8: { +// StorageDead(_4); +// StorageDead(_2); +// StorageDead(_1); +// return; +// } +// END rustc.node4.SimplifyCfg.initial-after.mir diff --git a/src/test/mir-opt/issue-38669.rs b/src/test/mir-opt/issue-38669.rs new file mode 100644 index 0000000000000..1d452907cf59a --- /dev/null +++ b/src/test/mir-opt/issue-38669.rs @@ -0,0 +1,52 @@ +// Copyright 2017 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +// check that we don't StorageDead booleans before they are used + +fn main() { + let mut should_break = false; + loop { + if should_break { + break; + } + should_break = true; + } +} + +// END RUST SOURCE +// START rustc.node4.SimplifyCfg.initial-after.mir +// bb0: { +// StorageLive(_1); +// _1 = const false; +// goto -> bb1; +// } +// +// bb1: { +// StorageLive(_4); +// _4 = _1; +// switchInt(_4) -> [0u8: bb3, otherwise: bb2]; +// } +// +// bb2: { +// StorageLive(_6); +// _0 = (); +// StorageDead(_4); +// StorageDead(_1); +// return; +// } +// +// bb3: { +// _3 = (); +// StorageDead(_4); +// _1 = const true; +// _2 = (); +// goto -> bb1; +// } +// END rustc.node4.SimplifyCfg.initial-after.mir diff --git a/src/test/mir-opt/storage_ranges.rs b/src/test/mir-opt/storage_ranges.rs index 933bfa8df2ec2..3fbd1a36f2f16 100644 --- a/src/test/mir-opt/storage_ranges.rs +++ b/src/test/mir-opt/storage_ranges.rs @@ -28,16 +28,15 @@ fn main() { // StorageLive(_5); // _5 = _1; // _4 = std::option::Option::Some(_5,); -// _3 = &_4; // StorageDead(_5); +// _3 = &_4; // _2 = (); -// StorageDead(_4); // StorageDead(_3); +// StorageDead(_4); // StorageLive(_6); // _6 = const 1i32; // _0 = (); // StorageDead(_6); // StorageDead(_1); -// return; -// } +// } // END rustc.node4.TypeckMir.before.mir diff --git a/src/test/run-pass/mir_drop_order.rs b/src/test/run-pass/mir_drop_order.rs new file mode 100644 index 0000000000000..e7da43597f169 --- /dev/null +++ b/src/test/run-pass/mir_drop_order.rs @@ -0,0 +1,55 @@ +// Copyright 2017 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 or the MIT license +// , at your +// option. This file may not be copied, modified, or distributed +// except according to those terms. + +use std::cell::RefCell; +use std::panic; + +pub struct DropLogger<'a> { + id: usize, + log: &'a panic::AssertUnwindSafe>> +} + +impl<'a> Drop for DropLogger<'a> { + fn drop(&mut self) { + self.log.0.borrow_mut().push(self.id); + } +} + +struct InjectedFailure; + +#[allow(unreachable_code)] +fn main() { + let log = panic::AssertUnwindSafe(RefCell::new(vec![])); + let d = |id| DropLogger { id: id, log: &log }; + let get = || -> Vec<_> { + let mut m = log.0.borrow_mut(); + let n = m.drain(..); + n.collect() + }; + + { + let _x = (d(0), &d(1), d(2), &d(3)); + // all borrows are extended - nothing has been dropped yet + assert_eq!(get(), vec![]); + } + // in a let-statement, extended lvalues are dropped + // *after* the let result (tho they have the same scope + // as far as scope-based borrowck goes). + assert_eq!(get(), vec![0, 2, 3, 1]); + + let _ = std::panic::catch_unwind(|| { + (d(4), &d(5), d(6), &d(7), panic!(InjectedFailure)); + }); + + // here, the temporaries (5/7) live until the end of the + // containing statement, which is destroyed after the operands + // (4/6) on a panic. + assert_eq!(get(), vec![6, 4, 7, 5]); +}