Attempt to print liveness results for yield expressions. Currently fails because this creates a type checking cycle.

Author: eholk

compiler/rustc_middle/src/hir/map/mod.rs

@@ -179,7 +179,7 @@ impl<'hir> Map<'hir> {
     pub fn local_def_id(&self, hir_id: HirId) -> LocalDefId {
         self.opt_local_def_id(hir_id).unwrap_or_else(|| {
             bug!(
-                "local_def_id: no entry for `{:?}`, which has a map of `{:?}`",
+                "local_def_id: no entry for `{:#?}`, which has a map of `{:#?}`",
                 hir_id,
                 self.find(hir_id)
             )

compiler/rustc_passes/src/liveness.rs

@@ -192,7 +192,7 @@ enum VarKind {
 pub struct IrMaps<'tcx> {
     tcx: TyCtxt<'tcx>,
     live_node_map: HirIdMap<LiveNode>,
-    variable_map: HirIdMap<Variable>,
+    pub variable_map: HirIdMap<Variable>,
     capture_info_map: HirIdMap<Rc<Vec<CaptureInfo>>>,
     var_kinds: IndexVec<Variable, VarKind>,
     lnks: IndexVec<LiveNode, LiveNodeKind>,
@@ -248,7 +248,7 @@ impl IrMaps<'tcx> {
         }
     }
 
-    fn variable_name(&self, var: Variable) -> Symbol {
+    pub fn variable_name(&self, var: Variable) -> Symbol {
         match self.var_kinds[var] {
             Local(LocalInfo { name, .. }) | Param(_, name) | Upvar(_, name) => name,
         }
@@ -481,7 +481,7 @@ pub fn compute_body_liveness(
     body_id: hir::BodyId,
 ) -> Liveness<'a, 'tcx> {
     let body = maps.tcx.hir().body(body_id);
-    let local_def_id = maps.tcx.hir().local_def_id(body_id.hir_id);
+    let local_def_id = maps.tcx.hir().local_def_id(maps.tcx.hir().body_owner(body_id));
 
     // gather up the various local variables, significant expressions,
     // and so forth:
@@ -505,7 +505,7 @@ const ACC_WRITE: u32 = 2;
 const ACC_USE: u32 = 4;
 
 pub struct Liveness<'a, 'tcx> {
-    ir: &'a mut IrMaps<'tcx>,
+    pub ir: &'a mut IrMaps<'tcx>,
     typeck_results: &'a ty::TypeckResults<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     closure_min_captures: Option<&'tcx RootVariableMinCaptureList<'tcx>>,
@@ -552,7 +552,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
         }
     }
 
-    fn live_node(&self, hir_id: HirId, span: Span) -> LiveNode {
+    pub fn live_node(&self, hir_id: HirId, span: Span) -> LiveNode {
         match self.ir.live_node_map.get(&hir_id) {
             Some(&ln) => ln,
             None => {
@@ -583,7 +583,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
         succ
     }
 
-    fn live_on_entry(&self, ln: LiveNode, var: Variable) -> bool {
+    pub fn live_on_entry(&self, ln: LiveNode, var: Variable) -> bool {
         self.rwu_table.get_reader(ln, var)
     }
 

compiler/rustc_typeck/src/check/generator_interior.rs

@@ -13,7 +13,7 @@ use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
 use rustc_hir::{Arm, Expr, ExprKind, Guard, HirId, Pat, PatKind};
 use rustc_middle::middle::region::{self, YieldData};
 use rustc_middle::ty::{self, Ty};
-use rustc_passes::liveness::{compute_body_liveness, IrMaps};
+use rustc_passes::liveness::{compute_body_liveness, IrMaps, Liveness};
 use rustc_span::Span;
 use smallvec::SmallVec;
 
@@ -31,6 +31,7 @@ struct InteriorVisitor<'a, 'tcx> {
     /// that they may succeed the said yield point in the post-order.
     guard_bindings: SmallVec<[SmallVec<[HirId; 4]>; 1]>,
     guard_bindings_set: HirIdSet,
+    liveness: Liveness<'a, 'tcx>,
 }
 
 impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> {
@@ -156,7 +157,7 @@ pub fn resolve_interior<'a, 'tcx>(
 ) {
     let mut ir_maps = IrMaps::new(fcx.tcx);
     // FIXME: use this to inform capture information
-    let _liveness = compute_body_liveness(&mut ir_maps, body_id);
+    let liveness = compute_body_liveness(&mut ir_maps, body_id);
     let body = fcx.tcx.hir().body(body_id);
     let mut visitor = InteriorVisitor {
         fcx,
@@ -167,6 +168,7 @@ pub fn resolve_interior<'a, 'tcx>(
         prev_unresolved_span: None,
         guard_bindings: <_>::default(),
         guard_bindings_set: <_>::default(),
+        liveness,
     };
     intravisit::walk_body(&mut visitor, body);
 
@@ -336,6 +338,21 @@ impl<'a, 'tcx> Visitor<'tcx> for InteriorVisitor<'a, 'tcx> {
                     _ => {}
                 }
             }
+            ExprKind::Yield(..) => {
+                let live_node = self.liveness.live_node(expr.hir_id, expr.span);
+
+                for (_, &var) in self.liveness.ir.variable_map.iter() {
+                    if self.liveness.live_on_entry(live_node, var) {
+                        debug!(
+                            "Variable {:?} is live on entry at {:?}",
+                            self.liveness.ir.variable_name(var),
+                            expr.span
+                        );
+                    }
+                }
+
+                intravisit::walk_expr(self, expr)
+            }
             _ => intravisit::walk_expr(self, expr),
         }