Start a new version of generator liveness.

Author: eholk

Cargo.lock

@@ -4506,6 +4506,7 @@ dependencies = [
  "rustc_lint",
  "rustc_macros",
  "rustc_middle",
+ "rustc_passes",
  "rustc_session",
  "rustc_span",
  "rustc_target",

compiler/rustc_passes/src/lib.rs

@@ -32,7 +32,7 @@ mod intrinsicck;
 mod lang_items;
 pub mod layout_test;
 mod lib_features;
-mod liveness;
+pub mod liveness;
 pub mod loops;
 mod naked_functions;
 mod reachable;

compiler/rustc_passes/src/liveness.rs

@@ -176,20 +176,24 @@ struct CaptureInfo {
 }
 
 #[derive(Copy, Clone, Debug)]
-struct LocalInfo {
+pub struct LocalInfo {
     id: HirId,
     name: Symbol,
     is_shorthand: bool,
 }
 
 #[derive(Copy, Clone, Debug)]
-enum VarKind {
+pub enum VarKind {
     Param(HirId, Symbol),
     Local(LocalInfo),
     Upvar(HirId, Symbol),
+    /// A virtual variable for a temporary expression.
+    ///
+    /// Used primarily by generator_interior.
+    Temporary(HirId),
 }
 
-struct IrMaps<'tcx> {
+pub struct IrMaps<'tcx> {
     tcx: TyCtxt<'tcx>,
     live_node_map: HirIdMap<LiveNode>,
     variable_map: HirIdMap<Variable>,
@@ -225,11 +229,14 @@ impl IrMaps<'tcx> {
         debug!("{:?} is node {:?}", ln, hir_id);
     }
 
-    fn add_variable(&mut self, vk: VarKind) -> Variable {
+    pub fn add_variable(&mut self, vk: VarKind) -> Variable {
         let v = self.var_kinds.push(vk);
 
         match vk {
-            Local(LocalInfo { id: node_id, .. }) | Param(node_id, _) | Upvar(node_id, _) => {
+            Local(LocalInfo { id: node_id, .. })
+            | Param(node_id, _)
+            | Upvar(node_id, _)
+            | Temporary(node_id) => {
                 self.variable_map.insert(node_id, v);
             }
         }
@@ -251,13 +258,14 @@ impl IrMaps<'tcx> {
     fn variable_name(&self, var: Variable) -> Symbol {
         match self.var_kinds[var] {
             Local(LocalInfo { name, .. }) | Param(_, name) | Upvar(_, name) => name,
+            Temporary(..) => Symbol::intern("[temporary]"),
         }
     }
 
     fn variable_is_shorthand(&self, var: Variable) -> bool {
         match self.var_kinds[var] {
             Local(LocalInfo { is_shorthand, .. }) => is_shorthand,
-            Param(..) | Upvar(..) => false,
+            Param(..) | Upvar(..) | Temporary(..) => false,
         }
     }
 
@@ -485,7 +493,7 @@ const ACC_READ: u32 = 1;
 const ACC_WRITE: u32 = 2;
 const ACC_USE: u32 = 4;
 
-struct Liveness<'a, 'tcx> {
+pub struct Liveness<'a, 'tcx> {
     ir: &'a mut IrMaps<'tcx>,
     typeck_results: &'a ty::TypeckResults<'tcx>,
     param_env: ty::ParamEnv<'tcx>,

compiler/rustc_typeck/Cargo.toml

@@ -17,6 +17,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_hir_pretty = { path = "../rustc_hir_pretty" }
+rustc_passes = { path = "../rustc_passes" }
 rustc_target = { path = "../rustc_target" }
 rustc_session = { path = "../rustc_session" }
 smallvec = { version = "1.6.1", features = ["union", "may_dangle"] }

compiler/rustc_typeck/src/check/generator_liveness.rs

@@ -0,0 +1,39 @@
+use crate::expr_use_visitor;
+use rustc_passes::liveness::{IrMaps, VarKind};
+
+use VarKind::*;
+
+impl<'tcx> expr_use_visitor::Delegate<'tcx> for IrMaps<'tcx> {
+    fn consume(
+        &mut self,
+        place_with_id: &rustc_middle::hir::place::PlaceWithHirId<'tcx>,
+        _diag_expr_id: rustc_hir::HirId,
+    ) {
+        self.add_variable(Temporary(place_with_id.hir_id));
+    }
+
+    fn borrow(
+        &mut self,
+        place_with_id: &rustc_middle::hir::place::PlaceWithHirId<'tcx>,
+        _diag_expr_id: rustc_hir::HirId,
+        _bk: rustc_middle::ty::BorrowKind,
+    ) {
+        self.add_variable(Temporary(place_with_id.hir_id));
+    }
+
+    fn mutate(
+        &mut self,
+        assignee_place: &rustc_middle::hir::place::PlaceWithHirId<'tcx>,
+        _diag_expr_id: rustc_hir::HirId,
+    ) {
+        self.add_variable(Temporary(assignee_place.hir_id));
+    }
+
+    fn fake_read(
+        &mut self,
+        _place: rustc_middle::hir::place::Place<'tcx>,
+        _cause: rustc_middle::mir::FakeReadCause,
+        _diag_expr_id: rustc_hir::HirId,
+    ) {
+    }
+}

compiler/rustc_typeck/src/check/mod.rs

@@ -79,6 +79,7 @@ mod fallback;
 mod fn_ctxt;
 mod gather_locals;
 mod generator_interior;
+mod generator_liveness;
 mod inherited;
 pub mod intrinsic;
 pub mod method;