restructure `CollectItem` dep-node to separate fn sigs from bodies

Setup two tasks, one of which only processes the signatures, in order to
isolate the typeck entries for signatures from those for bodies.

Fixes #36078
Fixes #37720

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 0fc8bf9e17de2e06dca4e9f260917e4fd1a17b05..d19bef6babea283e57557f849ac93c2232545531 100644 (file)
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -62,6 +62,7 @@ pub enum DepNode<D: Clone + Debug> {
     PluginRegistrar,
     StabilityIndex,
     CollectItem(D),
+    CollectItemSig(D),
     Coherence,
     EffectCheck,
     Liveness,
@@ -206,6 +207,7 @@ pub fn map_def<E, OP>(&self, mut op: OP) -> Option<DepNode<E>>
             HirBody(ref d) => op(d).map(HirBody),
             MetaData(ref d) => op(d).map(MetaData),
             CollectItem(ref d) => op(d).map(CollectItem),
+            CollectItemSig(ref d) => op(d).map(CollectItemSig),
             CoherenceCheckImpl(ref d) => op(d).map(CoherenceCheckImpl),
             CoherenceOverlapCheck(ref d) => op(d).map(CoherenceOverlapCheck),
             CoherenceOverlapCheckSpecial(ref d) => op(d).map(CoherenceOverlapCheckSpecial),

diff --git a/src/librustc_typeck/collect.rs b/src/librustc_typeck/collect.rs
index bdf0f988117349a69524b7aefdbe9c297fdc2c55..09e54cb9c5366ea34b502dc713fd6a95a13a3852 100644 (file)
--- a/src/librustc_typeck/collect.rs
+++ b/src/librustc_typeck/collect.rs
@@ -128,13 +128,62 @@ struct CollectItemTypesVisitor<'a, 'tcx: 'a> {
     ccx: &'a CrateCtxt<'a, 'tcx>
 }
 
+impl<'a, 'tcx> CollectItemTypesVisitor<'a, 'tcx> {
+    /// Collect item types is structured into two tasks. The outer
+    /// task, `CollectItem`, walks the entire content of an item-like
+    /// thing, including its body. It also spawns an inner task,
+    /// `CollectItemSig`, which walks only the signature. This inner
+    /// task is the one that writes the item-type into the various
+    /// maps.  This setup ensures that the item body is never
+    /// accessible to the task that computes its signature, so that
+    /// changes to the body don't affect the signature.
+    ///
+    /// Consider an example function `foo` that also has a closure in its body:
+    ///
+    /// ```
+    /// fn foo(<sig>) {
+    ///     ...
+    ///     let bar = || ...; // we'll label this closure as "bar" below
+    /// }
+    /// ```
+    ///
+    /// This results in a dep-graph like so. I've labeled the edges to
+    /// document where they arise.
+    ///
+    /// ```
+    /// [HirBody(foo)] -2--> [CollectItem(foo)] -4-> [ItemSignature(bar)]
+    ///                       ^           ^
+    ///                       1           3
+    /// [Hir(foo)] -----------+-6-> [CollectItemSig(foo)] -5-> [ItemSignature(foo)]
+    /// ```
+    ///
+    /// 1. This is added by the `visit_all_item_likes_in_krate`.
+    /// 2. This is added when we fetch the item body.
+    /// 3. This is added because `CollectItem` launches `CollectItemSig`.
+    ///    - it is arguably false; if we refactor the `with_task` system;
+    ///      we could get probably rid of it, but it is also harmless enough.
+    /// 4. This is added by the code in `visit_expr` when we write to `item_types`.
+    /// 5. This is added by the code in `convert_item` when we write to `item_types`;
+    ///    note that this write occurs inside the `CollectItemSig` task.
+    /// 6. Added by explicit `read` below
+    fn with_collect_item_sig<OP>(&self, id: ast::NodeId, op: OP)
+        where OP: FnOnce()
+    {
+        let def_id = self.ccx.tcx.map.local_def_id(id);
+        self.ccx.tcx.dep_graph.with_task(DepNode::CollectItemSig(def_id), || {
+            self.ccx.tcx.map.read(id);
+            op();
+        });
+    }
+}
+
 impl<'a, 'tcx> Visitor<'tcx> for CollectItemTypesVisitor<'a, 'tcx> {
     fn nested_visit_map(&mut self) -> Option<(&hir::map::Map<'tcx>, NestedVisitMode)> {
         Some((&self.ccx.tcx.map, NestedVisitMode::OnlyBodies))
     }
 
     fn visit_item(&mut self, item: &'tcx hir::Item) {
-        convert_item(self.ccx, item);
+        self.with_collect_item_sig(item.id, || convert_item(self.ccx, item));
         intravisit::walk_item(self, item);
     }
 
@@ -156,7 +205,9 @@ fn visit_ty(&mut self, ty: &'tcx hir::Ty) {
     }
 
     fn visit_impl_item(&mut self, impl_item: &'tcx hir::ImplItem) {
-        convert_impl_item(self.ccx, impl_item);
+        self.with_collect_item_sig(impl_item.id, || {
+            convert_impl_item(self.ccx, impl_item)
+        });
         intravisit::walk_impl_item(self, impl_item);
     }
 }

diff --git a/src/test/incremental/change_private_impl_method_cc/struct_point.rs b/src/test/incremental/change_private_impl_method_cc/struct_point.rs
index bb7f7025c59052d14bdffb5f8e80791834fbfcec..4d9ca77969bd7359e7f4f71f6816f5c7e3cc561e 100644 (file)
--- a/src/test/incremental/change_private_impl_method_cc/struct_point.rs
+++ b/src/test/incremental/change_private_impl_method_cc/struct_point.rs
@@ -23,9 +23,8 @@
 #![rustc_partition_reused(module="struct_point-fn_write_field", cfg="rpass2")]
 #![rustc_partition_reused(module="struct_point-fn_make_struct", cfg="rpass2")]
 
-// FIXME(#37720) these two should be reused, but data gets entangled across crates
-#![rustc_partition_translated(module="struct_point-fn_calls_methods_in_same_impl", cfg="rpass2")]
-#![rustc_partition_translated(module="struct_point-fn_calls_methods_in_another_impl", cfg="rpass2")]
+#![rustc_partition_reused(module="struct_point-fn_calls_methods_in_same_impl", cfg="rpass2")]
+#![rustc_partition_reused(module="struct_point-fn_calls_methods_in_another_impl", cfg="rpass2")]
 
 extern crate point;
 
@@ -33,8 +32,7 @@
 mod fn_calls_methods_in_same_impl {
     use point::Point;
 
-    // FIXME(#37720) data gets entangled across crates
-    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
     pub fn check() {
         let x = Point { x: 2.0, y: 2.0 };
         x.distance_from_origin();
@@ -45,8 +43,7 @@ pub fn check() {
 mod fn_calls_methods_in_another_impl {
     use point::Point;
 
-    // FIXME(#37720) data gets entangled across crates
-    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
     pub fn dirty() {
         let mut x = Point { x: 2.0, y: 2.0 };
         x.translate(3.0, 3.0);

diff --git a/src/test/incremental/change_pub_inherent_method_body/struct_point.rs b/src/test/incremental/change_pub_inherent_method_body/struct_point.rs
index 665eafb4f4eeb66fcd3310a506b575c4f163374a..e0047e5ec6455aa805b60c183ee43175fb90918d 100644 (file)
--- a/src/test/incremental/change_pub_inherent_method_body/struct_point.rs
+++ b/src/test/incremental/change_pub_inherent_method_body/struct_point.rs
@@ -19,9 +19,7 @@
 
 #![rustc_partition_translated(module="struct_point-point", cfg="rpass2")]
 
-// FIXME(#35078) -- this gets recompiled because we don't separate sig from body
-#![rustc_partition_translated(module="struct_point-fn_calls_changed_method", cfg="rpass2")]
-
+#![rustc_partition_reused(module="struct_point-fn_calls_changed_method", cfg="rpass2")]
 #![rustc_partition_reused(module="struct_point-fn_calls_another_method", cfg="rpass2")]
 #![rustc_partition_reused(module="struct_point-fn_make_struct", cfg="rpass2")]
 #![rustc_partition_reused(module="struct_point-fn_read_field", cfg="rpass2")]
@@ -52,8 +50,7 @@ pub fn x(&self) -> f32 {
 mod fn_calls_changed_method {
     use point::Point;
 
-    // FIXME(#35078) -- this gets recompiled because we don't separate sig from body
-    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
     pub fn check() {
         let p = Point { x: 2.0, y: 2.0 };
         p.distance_from_origin();

diff --git a/src/test/incremental/hello_world.rs b/src/test/incremental/hello_world.rs
index 14e4cfcd988db92d24818adf7822585080f67275..b7f90c09b565cd41e552856c2c75d2bcf8f999bf 100644 (file)
--- a/src/test/incremental/hello_world.rs
+++ b/src/test/incremental/hello_world.rs
@@ -31,8 +31,7 @@ pub fn xxxx() -> i32 {
 mod y {
     use x;
 
-    // FIXME: This should be clean
-    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
     pub fn yyyy() {
         x::xxxx();
     }