liveness: Include upvars in the analysis

src/librustc_passes/liveness.rs

@@ -244,6 +244,7 @@ struct LocalInfo {
 enum VarKind {
  Param(HirId, Symbol),
  Local(LocalInfo),
+ Upvar(HirId, Symbol),
 }
 
 struct IrMaps<'tcx> {
@@ -296,7 +297,7 @@ impl IrMaps<'tcx> {
  self.num_vars += 1;
 
  match vk {
- Local(LocalInfo { id: node_id, .. }) | Param(node_id, _) => {
+ Local(LocalInfo { id: node_id, .. }) | Param(node_id, _) | Upvar(node_id, _) => {
  self.variable_map.insert(node_id, v);
  }
  }
@@ -317,14 +318,14 @@ impl IrMaps<'tcx> {
 
  fn variable_name(&self, var: Variable) -> String {
  match self.var_kinds[var.get()] {
- Local(LocalInfo { name, .. }) | Param(_, name) => name.to_string(),
+ Local(LocalInfo { name, .. }) | Param(_, name) | Upvar(_, name) => name.to_string(),
  }
  }
 
  fn variable_is_shorthand(&self, var: Variable) -> bool {
  match self.var_kinds[var.get()] {
  Local(LocalInfo { is_shorthand, .. }) => is_shorthand,
- Param(..) => false,
+ Param(..) | Upvar(..) => false,
  }
  }
 
@@ -365,6 +366,14 @@ fn visit_fn<'tcx>(
 
  let body = ir.tcx.hir().body(body_id);
 
+ if let Some(upvars) = ir.tcx.upvars_mentioned(def_id) {
+ for (&var_hir_id, _upvar) in upvars {
+ debug!("adding upvar {:?}", var_hir_id);
+ let var_name = ir.tcx.hir().name(var_hir_id);
+ fn_maps.add_variable(Upvar(var_hir_id, var_name));
+ }
+ }
+
  for param in body.params {
  let is_shorthand = match param.pat.kind {
  rustc_hir::PatKind::Struct(..) => true,
@@ -450,11 +459,8 @@ fn visit_expr<'tcx>(ir: &mut IrMaps<'tcx>, expr: &'tcx Expr<'tcx>) {
  // live nodes required for uses or definitions of variables:
  hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) => {
  debug!("expr {}: path that leads to {:?}", expr.hir_id, path.res);
- if let Res::Local(var_hir_id) = path.res {
- let upvars = ir.tcx.upvars_mentioned(ir.body_owner);
- if !upvars.map_or(false, |upvars| upvars.contains_key(&var_hir_id)) {
- ir.add_live_node_for_node(expr.hir_id, ExprNode(expr.span));
- }
+ if let Res::Local(_var_hir_id) = path.res {
+ ir.add_live_node_for_node(expr.hir_id, ExprNode(expr.span));
  }
  intravisit::walk_expr(ir, expr);
  }
@@ -470,16 +476,9 @@ fn visit_expr<'tcx>(ir: &mut IrMaps<'tcx>, expr: &'tcx Expr<'tcx>) {
  let mut call_caps = Vec::new();
  let closure_def_id = ir.tcx.hir().local_def_id(expr.hir_id);
  if let Some(upvars) = ir.tcx.upvars_mentioned(closure_def_id) {
- let parent_upvars = ir.tcx.upvars_mentioned(ir.body_owner);
- call_caps.extend(upvars.iter().filter_map(|(&var_id, upvar)| {
- let has_parent =
- parent_upvars.map_or(false, |upvars| upvars.contains_key(&var_id));
- if !has_parent {
- let upvar_ln = ir.add_live_node(UpvarNode(upvar.span));
- Some(CaptureInfo { ln: upvar_ln, var_hid: var_id })
- } else {
- None
- }
+ call_caps.extend(upvars.iter().map(|(&var_id, upvar)| {
+ let upvar_ln = ir.add_live_node(UpvarNode(upvar.span));
+ CaptureInfo { ln: upvar_ln, var_hid: var_id }
  }));
  }
  ir.set_captures(expr.hir_id, call_caps);
@@ -894,6 +893,14 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  debug!("compute: using id for body, {:?}", body);
 
  let s = self.s;
+
+ if let Some(upvars) = self.ir.tcx.upvars_mentioned(self.ir.body_owner) {
+ for (&var_hir_id, upvar) in upvars.iter().rev() {
+ let var = self.variable(var_hir_id, upvar.span);
+ self.acc(s.exit_ln, var, ACC_READ | ACC_USE);
+ }
+ }
+
  let entry_ln = self.propagate_through_expr(body, s.exit_ln);
 
  // hack to skip the loop unless debug! is enabled:
@@ -1345,14 +1352,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
  acc: u32,
  ) -> LiveNode {
  match path.res {
- Res::Local(hid) => {
- let upvars = self.ir.tcx.upvars_mentioned(self.ir.body_owner);
- if !upvars.map_or(false, |upvars| upvars.contains_key(&hid)) {
- self.access_var(hir_id, hid, succ, acc, path.span)
- } else {
- succ
- }
- }
+ Res::Local(hid) => self.access_var(hir_id, hid, succ, acc, path.span),
  _ => succ,
  }
  }
@@ -1511,16 +1511,13 @@ impl<'tcx> Liveness<'_, 'tcx> {
  match expr.kind {
  hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) => {
  if let Res::Local(var_hid) = path.res {
- let upvars = self.ir.tcx.upvars_mentioned(self.ir.body_owner);
- if !upvars.map_or(false, |upvars| upvars.contains_key(&var_hid)) {
- // Assignment to an immutable variable or argument: only legal
- // if there is no later assignment. If this local is actually
- // mutable, then check for a reassignment to flag the mutability
- // as being used.
- let ln = self.live_node(expr.hir_id, expr.span);
- let var = self.variable(var_hid, expr.span);
- self.warn_about_dead_assign(vec![expr.span], expr.hir_id, ln, var);
- }
+ // Assignment to an immutable variable or argument: only legal
+ // if there is no later assignment. If this local is actually
+ // mutable, then check for a reassignment to flag the mutability
+ // as being used.
+ let ln = self.live_node(expr.hir_id, expr.span);
+ let var = self.variable(var_hid, expr.span);
+ self.warn_about_dead_assign(vec![expr.span], expr.hir_id, ln, var);
  }
  }
  _ => {