Auto merge of #44878 - Nashenas88:master, r=nikomatsakis

Store a new Region value every time we create a new region variable

Paired with @spastorino to walk through this and implement #44870.

src/Cargo.lock

@@ -1668,6 +1668,7 @@ dependencies = [
  "rustc_const_math 0.0.0",
  "rustc_data_structures 0.0.0",
  "rustc_errors 0.0.0",
+ "serialize 0.0.0",
  "syntax 0.0.0",
  "syntax_pos 0.0.0",
 ]

src/librustc/dep_graph/graph.rs

@@ -406,7 +406,7 @@ impl DepGraph {
         for (current_dep_node_index, edges) in current_dep_graph.edges.iter_enumerated() {
             let start = edge_list_data.len() as u32;
             // This should really just be a memcpy :/
-            edge_list_data.extend(edges.iter().map(|i| SerializedDepNodeIndex(i.index)));
+            edge_list_data.extend(edges.iter().map(|i| SerializedDepNodeIndex::new(i.index())));
             let end = edge_list_data.len() as u32;
 
             debug_assert_eq!(current_dep_node_index.index(), edge_list_indices.len());

src/librustc/dep_graph/serialized.rs

@@ -14,23 +14,7 @@ use dep_graph::DepNode;
 use ich::Fingerprint;
 use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 
-/// The index of a DepNode in the SerializedDepGraph::nodes array.
-#[derive(Copy, Clone, Hash, Eq, PartialEq, Ord, PartialOrd, Debug,
-         RustcEncodable, RustcDecodable)]
-pub struct SerializedDepNodeIndex(pub u32);
-
-impl Idx for SerializedDepNodeIndex {
-    #[inline]
-    fn new(idx: usize) -> Self {
-        assert!(idx <= ::std::u32::MAX as usize);
-        SerializedDepNodeIndex(idx as u32)
-    }
-
-    #[inline]
-    fn index(self) -> usize {
-        self.0 as usize
-    }
-}
+newtype_index!(SerializedDepNodeIndex);
 
 /// Data for use when recompiling the **current crate**.
 #[derive(Debug, RustcEncodable, RustcDecodable)]

src/librustc/lib.rs

@@ -43,6 +43,7 @@
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(conservative_impl_trait)]
+#![feature(const_fn)]
 #![feature(core_intrinsics)]
 #![feature(i128_type)]
 #![cfg_attr(windows, feature(libc))]
@@ -71,7 +72,7 @@ extern crate graphviz;
 extern crate libc;
 extern crate owning_ref;
 extern crate rustc_back;
-extern crate rustc_data_structures;
+#[macro_use] extern crate rustc_data_structures;
 extern crate serialize;
 extern crate rustc_const_math;
 extern crate rustc_errors as errors;

src/librustc/mir/mod.rs

@@ -43,30 +43,6 @@ pub mod visit;
 pub mod transform;
 pub mod traversal;
 
-macro_rules! newtype_index {
-    ($name:ident, $debug_name:expr) => (
-        #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord,
-         RustcEncodable, RustcDecodable)]
-        pub struct $name(u32);
-
-        impl Idx for $name {
-            fn new(value: usize) -> Self {
-                assert!(value < (u32::MAX) as usize);
-                $name(value as u32)
-            }
-            fn index(self) -> usize {
-                self.0 as usize
-            }
-        }
-
-        impl Debug for $name {
-            fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
-                write!(fmt, "{}{}", $debug_name, self.0)
-            }
-        }
-    )
-}
-
 /// Types for locals
 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
 

src/librustc_data_structures/indexed_vec.rs

@@ -38,6 +38,43 @@ impl Idx for u32 {
     fn index(self) -> usize { self as usize }
 }
 
+#[macro_export]
+macro_rules! newtype_index {
+    ($name:ident) => (
+        newtype_index!($name, unsafe { ::std::intrinsics::type_name::<$name>() });
+    );
+
+    ($name:ident, $debug_name:expr) => (
+        #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord,
+         RustcEncodable, RustcDecodable)]
+        pub struct $name(u32);
+
+        impl $name {
+            // HACK use for constants
+            #[allow(unused)]
+            const fn const_new(x: u32) -> Self {
+                $name(x)
+            }
+        }
+
+        impl Idx for $name {
+            fn new(value: usize) -> Self {
+                assert!(value < (::std::u32::MAX) as usize);
+                $name(value as u32)
+            }
+            fn index(self) -> usize {
+                self.0 as usize
+            }
+        }
+
+        impl ::std::fmt::Debug for $name {
+            fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+                write!(fmt, "{}{}", $debug_name, self.0)
+            }
+        }
+    )
+}
+
 #[derive(Clone, PartialEq, Eq)]
 pub struct IndexVec<I: Idx, T> {
     pub raw: Vec<T>,

src/librustc_mir/Cargo.toml

@@ -17,5 +17,6 @@ rustc_const_eval = { path = "../librustc_const_eval" }
 rustc_const_math = { path = "../librustc_const_math" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
+serialize = { path = "../libserialize" }
 syntax = { path = "../libsyntax" }
 syntax_pos = { path = "../libsyntax_pos" }

src/librustc_mir/build/mod.rs

@@ -311,19 +311,7 @@ struct CFG<'tcx> {
     basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
-pub struct ScopeId(u32);
-
-impl Idx for ScopeId {
-    fn new(index: usize) -> ScopeId {
-        assert!(index < (u32::MAX as usize));
-        ScopeId(index as u32)
-    }
-
-    fn index(self) -> usize {
-        self.0 as usize
-    }
-}
+newtype_index!(ScopeId);
 
 ///////////////////////////////////////////////////////////////////////////
 /// The `BlockAnd` "monad" packages up the new basic block along with a

src/librustc_mir/lib.rs

@@ -18,6 +18,8 @@ Rust MIR: a lowered representation of Rust. Also: an experiment!
 
 #![feature(box_patterns)]
 #![feature(box_syntax)]
+#![feature(const_fn)]
+#![feature(core_intrinsics)]
 #![feature(i128_type)]
 #![feature(rustc_diagnostic_macros)]
 #![feature(placement_in_syntax)]
@@ -30,7 +32,8 @@ extern crate bitflags;
 extern crate graphviz as dot;
 #[macro_use]
 extern crate rustc;
-extern crate rustc_data_structures;
+#[macro_use] extern crate rustc_data_structures;
+extern crate serialize as rustc_serialize;
 extern crate rustc_errors;
 #[macro_use]
 extern crate syntax;

src/librustc_mir/transform/nll/mod.rs

@@ -15,12 +15,15 @@ use rustc::mir::{Mir, Location, Rvalue, BasicBlock, Statement, StatementKind};
 use rustc::mir::visit::{MutVisitor, Lookup};
 use rustc::mir::transform::{MirPass, MirSource};
 use rustc::infer::{self, InferCtxt};
+use rustc::util::nodemap::FxHashSet;
+use rustc_data_structures::indexed_vec::{IndexVec, Idx};
 use syntax_pos::DUMMY_SP;
 use std::collections::HashMap;
 
 #[allow(dead_code)]
 struct NLLVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
     lookup_map: HashMap<RegionVid, Lookup>,
+    regions: IndexVec<RegionIndex, Region>,
     infcx: InferCtxt<'a, 'gcx, 'tcx>,
 }
 
@@ -29,6 +32,7 @@ impl<'a, 'gcx, 'tcx> NLLVisitor<'a, 'gcx, 'tcx> {
         NLLVisitor {
             infcx,
             lookup_map: HashMap::new(),
+            regions: IndexVec::new(),
         }
     }
 
@@ -36,8 +40,9 @@ impl<'a, 'gcx, 'tcx> NLLVisitor<'a, 'gcx, 'tcx> {
         self.lookup_map
     }
 
-    fn renumber_regions<T>(&self, value: &T) -> T where T: TypeFoldable<'tcx> {
+    fn renumber_regions<T>(&mut self, value: &T) -> T where T: TypeFoldable<'tcx> {
         self.infcx.tcx.fold_regions(value, &mut false, |_region, _depth| {
+            self.regions.push(Region::default());
             self.infcx.next_region_var(infer::MiscVariable(DUMMY_SP))
         })
     }
@@ -143,4 +148,11 @@ impl MirPass for NLL {
             let _results = visitor.into_results();
         })
     }
-}
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+struct Region {
+    points: FxHashSet<Location>,
+}
+
+newtype_index!(RegionIndex);