Merge pull request #125 from lqd/a_region_has_no_name

Clean up terminology: step 1 — rename `Region` to `Origin`

Author: nikomatsakis

polonius-engine/src/facts.rs

@@ -3,68 +3,70 @@ use std::hash::Hash;
 
 /// The "facts" which are the basis of the NLL borrow analysis.
 #[derive(Clone, Debug)]
-pub struct AllFacts<R: Atom, L: Atom, P: Atom, V: Atom, M: Atom> {
-    /// `borrow_region(R, B, P)` -- the region R may refer to data
-    /// from borrow B starting at the point P (this is usually the
+pub struct AllFacts<Origin: Atom, Loan: Atom, Point: Atom, Variable: Atom, MovePath: Atom> {
+    /// `borrow_region(O, L, P)` -- the origin `O` may refer to data
+    /// from loan `L` starting at the point `P` (this is usually the
     /// point *after* a borrow rvalue)
-    pub borrow_region: Vec<(R, L, P)>,
+    pub borrow_region: Vec<(Origin, Loan, Point)>,
 
-    /// `universal_region(R)` -- this is a "free region" within fn body
-    pub universal_region: Vec<R>,
+    /// `universal_region(O)` -- this is a "free region" within fn body
+    pub universal_region: Vec<Origin>,
 
-    /// `cfg_edge(P,Q)` for each edge P -> Q in the control flow
-    pub cfg_edge: Vec<(P, P)>,
+    /// `cfg_edge(P, Q)` for each edge `P -> Q` in the control flow
+    pub cfg_edge: Vec<(Point, Point)>,
 
-    /// `killed(B,P)` when some prefix of the path borrowed at B is assigned at point P
-    pub killed: Vec<(L, P)>,
+    /// `killed(L, P)` when some prefix of the path borrowed at `L` is assigned at point `P`
+    pub killed: Vec<(Loan, Point)>,
 
-    /// `outlives(R1, R2, P)` when we require `R1@P: R2@P`
-    pub outlives: Vec<(R, R, P)>,
+    /// `outlives(O1, P2, P)` when we require `O1@P: O2@P`
+    pub outlives: Vec<(Origin, Origin, Point)>,
 
-    ///  `invalidates(P, L)` when the loan L is invalidated at point P
-    pub invalidates: Vec<(P, L)>,
+    ///  `invalidates(P, L)` when the loan `L` is invalidated at point `P`
+    pub invalidates: Vec<(Point, Loan)>,
 
-    /// `var_used(V, P) when the variable V is used for anything but a drop at point P`
-    pub var_used: Vec<(V, P)>,
+    /// `var_used(V, P)` when the variable `V` is used for anything but a drop at point `P`
+    pub var_used: Vec<(Variable, Point)>,
 
-    /// `var_defined(V, P) when the variable V is overwritten by the point P`
-    pub var_defined: Vec<(V, P)>,
+    /// `var_defined(V, P)` when the variable `V` is overwritten by the point `P`
+    pub var_defined: Vec<(Variable, Point)>,
 
-    /// `var_used(V, P) when the variable V is used in a drop at point P`
-    pub var_drop_used: Vec<(V, P)>,
+    /// `var_used(V, P)` when the variable `V` is used in a drop at point `P`
+    pub var_drop_used: Vec<(Variable, Point)>,
 
-    /// `var_uses_region(V, R) when the type of V includes the region R`
-    pub var_uses_region: Vec<(V, R)>,
+    /// `var_uses_region(V, O)` when the type of `V` includes the origin `O`
+    pub var_uses_region: Vec<(Variable, Origin)>,
 
-    /// `var_drops_region(V, R) when the type of V includes the region R and uses
-    /// it when dropping`
-    pub var_drops_region: Vec<(V, R)>,
+    /// `var_drops_region(V, O)` when the type of `V` includes the origin `O` and uses
+    /// it when dropping
+    pub var_drops_region: Vec<(Variable, Origin)>,
 
-    /// `child(M1, M2) when the move path `M1` is the direct or transitive child
+    /// `child(M1, M2)` when the move path `M1` is the direct or transitive child
     /// of `M2`, e.g. `child(x.y, x)`, `child(x.y.z, x.y)`, `child(x.y.z, x)`
     /// would all be true if there was a path like `x.y.z`.
-    pub child: Vec<(M, M)>,
+    pub child: Vec<(MovePath, MovePath)>,
 
-    /// `path_belongs_to_var(M, V) the root path `M` starting in variable `V`.
-    pub path_belongs_to_var: Vec<(M, V)>,
+    /// `path_belongs_to_var(M, V)` the root path `M` starting in variable `V`.
+    pub path_belongs_to_var: Vec<(MovePath, Variable)>,
 
-    /// `initialized_at(M, P) when the move path `M` was initialized at point
+    /// `initialized_at(M, P)` when the move path `M` was initialized at point
     /// `P`. This fact is only emitted for a prefix `M`, and not for the
     /// implicit initialization of all of `M`'s children. E.g. a statement like
     /// `x.y = 3` at point `P` would give the fact `initialized_at(x.y, P)` (but
     /// neither `initialized_at(x.y.z, P)` nor `initialized_at(x, P)`).
-    pub initialized_at: Vec<(M, P)>,
+    pub initialized_at: Vec<(MovePath, Point)>,
 
-    /// `moved_out_at(M, P) when the move path `M` was moved at point `P`. The
+    /// `moved_out_at(M, P)` when the move path `M` was moved at point `P`. The
     /// same logic is applied as for `initialized_at` above.
-    pub moved_out_at: Vec<(M, P)>,
+    pub moved_out_at: Vec<(MovePath, Point)>,
 
-    /// `path_accessed_at(M, P) when the move path `M` was accessed at point
+    /// `path_accessed_at(M, P)` when the move path `M` was accessed at point
     /// `P`. The same logic as for `initialized_at` and `moved_out_at` applies.
-    pub path_accessed_at: Vec<(M, P)>,
+    pub path_accessed_at: Vec<(MovePath, Point)>,
 }
 
-impl<R: Atom, L: Atom, P: Atom, V: Atom, M: Atom> Default for AllFacts<R, L, P, V, M> {
+impl<Origin: Atom, Loan: Atom, Point: Atom, Variable: Atom, MovePath: Atom> Default
+    for AllFacts<Origin, Loan, Point, Variable, MovePath>
+{
     fn default() -> Self {
         AllFacts {
             borrow_region: Vec::default(),

polonius-engine/src/output/datafrog_opt.rs

@@ -18,10 +18,10 @@ use crate::output::Output;
 use datafrog::{Iteration, Relation, RelationLeaper};
 use facts::{AllFacts, Atom};
 
-pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, MovePath: Atom>(
+pub(super) fn compute<Origin: Atom, Loan: Atom, Point: Atom, Variable: Atom, MovePath: Atom>(
     dump_enabled: bool,
-    all_facts: AllFacts<Region, Loan, Point, Variable, MovePath>,
-) -> Output<Region, Loan, Point, Variable, MovePath> {
+    all_facts: AllFacts<Origin, Loan, Point, Variable, MovePath>,
+) -> Output<Origin, Loan, Point, Variable, MovePath> {
     let mut result = Output::new(dump_enabled);
 
     let var_maybe_initialized_on_exit = initialization::init_var_maybe_initialized_on_exit(
@@ -62,22 +62,22 @@ pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, Mov
 
         // we need `region_live_at` in both variable and relation forms.
         // (respectively, for join and antijoin).
-        let region_live_at_rel: Relation<(Region, Point)> = region_live_at.into();
-        let region_live_at_var = iteration.variable::<((Region, Point), ())>("region_live_at");
+        let region_live_at_rel: Relation<(Origin, Point)> = region_live_at.into();
+        let region_live_at_var = iteration.variable::<((Origin, Point), ())>("region_live_at");
 
         // `borrow_region` input but organized for join
-        let borrow_region_rp = iteration.variable::<((Region, Point), Loan)>("borrow_region_rp");
+        let borrow_region_rp = iteration.variable::<((Origin, Point), Loan)>("borrow_region_rp");
 
         // .decl subset(R1, R2, P)
         //
         // Indicates that `R1: R2` at the point `P`.
-        let subset_r1p = iteration.variable::<((Region, Point), Region)>("subset_r1p");
+        let subset_r1p = iteration.variable::<((Origin, Point), Origin)>("subset_r1p");
 
         // .decl requires(R, B, P)
         //
-        // At the point, things with region R may depend on data from
+        // At the point, things with origin R may depend on data from
         // borrow B
-        let requires_rp = iteration.variable::<((Region, Point), Loan)>("requires_rp");
+        let requires_rp = iteration.variable::<((Origin, Point), Loan)>("requires_rp");
 
         // .decl borrow_live_at(B, P) -- true if the restrictions of the borrow B
         // need to be enforced at the point P
@@ -95,55 +95,55 @@ pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, Mov
         // live things reachable from `R2` to `R1`.
         //
         let live_to_dying_regions_r2pq =
-            iteration.variable::<((Region, Point, Point), Region)>("live_to_dying_regions_r2pq");
+            iteration.variable::<((Origin, Point, Point), Origin)>("live_to_dying_regions_r2pq");
 
         // .decl dying_region_requires((R, P, Q), B)
         //
-        // The region `R` requires the borrow `B`, but the
-        // region `R` goes dead along the edge `P -> Q`
+        // The origin `R` requires the borrow `B`, but the
+        // origin `R` goes dead along the edge `P -> Q`
         let dying_region_requires =
-            iteration.variable::<((Region, Point, Point), Loan)>("dying_region_requires");
+            iteration.variable::<((Origin, Point, Point), Loan)>("dying_region_requires");
 
         // .decl dying_can_reach_origins(R, P, Q)
         //
         // Contains dead regions where we are interested
         // in computing the transitive closure of things they
         // can reach.
         let dying_can_reach_origins =
-            iteration.variable::<((Region, Point), Point)>("dying_can_reach_origins");
+            iteration.variable::<((Origin, Point), Point)>("dying_can_reach_origins");
 
         // .decl dying_can_reach(R1, R2, P, Q)
         //
-        // Indicates that the region `R1`, which is dead
-        // in `Q`, can reach the region `R2` in P.
+        // Indicates that the origin `R1`, which is dead
+        // in `Q`, can reach the origin `R2` in P.
         //
         // This is effectively the transitive subset
         // relation, but we try to limit it to regions
         // that are dying on the edge P -> Q.
         let dying_can_reach_r2q =
-            iteration.variable::<((Region, Point), (Region, Point))>("dying_can_reach");
+            iteration.variable::<((Origin, Point), (Origin, Point))>("dying_can_reach");
         let dying_can_reach_1 = iteration.variable_indistinct("dying_can_reach_1");
 
         // .decl dying_can_reach_live(R1, R2, P, Q)
         //
         // Indicates that, along the edge `P -> Q`, the dead (in Q)
-        // region R1 can reach the live (in Q) region R2 via a subset
+        // origin R1 can reach the live (in Q) origin R2 via a subset
         // relation. This is a subset of the full `dying_can_reach`
         // relation where we filter down to those cases where R2 is
         // live in Q.
         let dying_can_reach_live =
-            iteration.variable::<((Region, Point, Point), Region)>("dying_can_reach_live");
+            iteration.variable::<((Origin, Point, Point), Origin)>("dying_can_reach_live");
 
         // .decl dead_borrow_region_can_reach_root((R, P), B)
         //
         // Indicates a "borrow region" R at P which is not live on
         // entry to P.
         let dead_borrow_region_can_reach_root =
-            iteration.variable::<((Region, Point), Loan)>("dead_borrow_region_can_reach_root");
+            iteration.variable::<((Origin, Point), Loan)>("dead_borrow_region_can_reach_root");
 
         // .decl dead_borrow_region_can_reach_dead((R2, P), B)
         let dead_borrow_region_can_reach_dead =
-            iteration.variable::<((Region, Point), Loan)>("dead_borrow_region_can_reach_dead");
+            iteration.variable::<((Origin, Point), Loan)>("dead_borrow_region_can_reach_dead");
         let dead_borrow_region_can_reach_dead_1 =
             iteration.variable_indistinct("dead_borrow_region_can_reach_dead_1");
 
@@ -234,7 +234,7 @@ pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, Mov
             //
             // This is the "transitive closure" rule, but
             // note that we only apply it with the
-            // "intermediate" region R2 is dead at Q.
+            // "intermediate" origin R2 is dead at Q.
             dying_can_reach_1.from_antijoin(
                 &dying_can_reach_r2q,
                 &region_live_at_rel,
@@ -288,7 +288,7 @@ pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, Mov
             //
             // Communicate a `R1 requires B` relation across
             // an edge `P -> Q` where `R1` is dead in Q; in
-            // that case, for each region `R2` live in `Q`
+            // that case, for each origin `R2` live in `Q`
             // where `R1 <= R2` in P, we add `R2 requires B`
             // to `Q`.
             requires_rp.from_join(
@@ -366,12 +366,12 @@ pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, Mov
         }
 
         if dump_enabled {
-            for (region, location) in &region_live_at_rel.elements {
+            for (origin, location) in &region_live_at_rel.elements {
                 result
                     .region_live_at
                     .entry(*location)
                     .or_insert(vec![])
-                    .push(*region);
+                    .push(*origin);
             }
 
             let subset_r1p = subset_r1p.complete();
@@ -390,12 +390,12 @@ pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, Mov
             }
 
             let requires_rp = requires_rp.complete();
-            for ((region, location), borrow) in &requires_rp.elements {
+            for ((origin, location), borrow) in &requires_rp.elements {
                 result
                     .restricts
                     .entry(*location)
                     .or_insert(BTreeMap::new())
-                    .entry(*region)
+                    .entry(*origin)
                     .or_insert(BTreeSet::new())
                     .insert(*borrow);
             }

polonius-engine/src/output/hybrid.rs

@@ -16,10 +16,10 @@ use crate::output::location_insensitive;
 use crate::output::Output;
 use facts::{AllFacts, Atom};
 
-pub(super) fn compute<Region: Atom, Loan: Atom, Point: Atom, Variable: Atom, MovePath: Atom>(
+pub(super) fn compute<Origin: Atom, Loan: Atom, Point: Atom, Variable: Atom, MovePath: Atom>(
     dump_enabled: bool,
-    all_facts: AllFacts<Region, Loan, Point, Variable, MovePath>,
-) -> Output<Region, Loan, Point, Variable, MovePath> {
+    all_facts: AllFacts<Origin, Loan, Point, Variable, MovePath>,
+) -> Output<Origin, Loan, Point, Variable, MovePath> {
     let lins_output = location_insensitive::compute(dump_enabled, &all_facts);
     if lins_output.errors.is_empty() {
         lins_output

polonius-engine/src/output/initialization.rs

@@ -5,17 +5,17 @@ use facts::Atom;
 
 use datafrog::{Iteration, Relation, RelationLeaper};
 
-pub(super) fn init_var_maybe_initialized_on_exit<Region, Loan, Point, Variable, MovePath>(
+pub(super) fn init_var_maybe_initialized_on_exit<Origin, Loan, Point, Variable, MovePath>(
     child: Vec<(MovePath, MovePath)>,
     path_belongs_to_var: Vec<(MovePath, Variable)>,
     initialized_at: Vec<(MovePath, Point)>,
     moved_out_at: Vec<(MovePath, Point)>,
     path_accessed_at: Vec<(MovePath, Point)>,
     cfg_edge: &[(Point, Point)],
-    output: &mut Output<Region, Loan, Point, Variable, MovePath>,
+    output: &mut Output<Origin, Loan, Point, Variable, MovePath>,
 ) -> Vec<(Variable, Point)>
 where
-    Region: Atom,
+    Origin: Atom,
     Loan: Atom,
     Point: Atom,
     Variable: Atom,

polonius-engine/src/output/liveness.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-//! An implementation of the region liveness calculation logic
+//! An implementation of the origin liveness calculation logic
 
 use std::collections::BTreeSet;
 use std::time::Instant;
@@ -18,18 +18,18 @@ use facts::Atom;
 
 use datafrog::{Iteration, Relation, RelationLeaper};
 
-pub(super) fn compute_live_regions<Region, Loan, Point, Variable, MovePath>(
+pub(super) fn compute_live_regions<Origin, Loan, Point, Variable, MovePath>(
     var_used: Vec<(Variable, Point)>,
     var_drop_used: Vec<(Variable, Point)>,
     var_defined: Vec<(Variable, Point)>,
-    var_uses_region: Vec<(Variable, Region)>,
-    var_drops_region: Vec<(Variable, Region)>,
+    var_uses_region: Vec<(Variable, Origin)>,
+    var_drops_region: Vec<(Variable, Origin)>,
     cfg_edge: &[(Point, Point)],
     var_maybe_initialized_on_exit: Vec<(Variable, Point)>,
-    output: &mut Output<Region, Loan, Point, Variable, MovePath>,
-) -> Vec<(Region, Point)>
+    output: &mut Output<Origin, Loan, Point, Variable, MovePath>,
+) -> Vec<(Origin, Point)>
 where
-    Region: Atom,
+    Origin: Atom,
     Loan: Atom,
     Point: Atom,
     Variable: Atom,
@@ -44,8 +44,8 @@ where
     let cfg_edge_rel: Relation<(Point, Point)> = cfg_edge.iter().map(|(p, q)| (*p, *q)).collect();
     let cfg_edge_reverse_rel: Relation<(Point, Point)> =
         cfg_edge.iter().map(|(p, q)| (*q, *p)).collect();
-    let var_uses_region_rel: Relation<(Variable, Region)> = var_uses_region.into();
-    let var_drops_region_rel: Relation<(Variable, Region)> = var_drops_region.into();
+    let var_uses_region_rel: Relation<(Variable, Origin)> = var_uses_region.into();
+    let var_drops_region_rel: Relation<(Variable, Origin)> = var_drops_region.into();
     let var_maybe_initialized_on_exit_rel: Relation<(Variable, Point)> =
         var_maybe_initialized_on_exit.into();
     let var_drop_used_rel: Relation<((Variable, Point), ())> = var_drop_used
@@ -61,7 +61,7 @@ where
     let var_drop_live_var = iteration.variable::<(Variable, Point)>("var_drop_live_at");
 
     // This is what we are actually calculating:
-    let region_live_at_var = iteration.variable::<((Region, Point), ())>("region_live_at");
+    let region_live_at_var = iteration.variable::<((Origin, Point), ())>("region_live_at");
 
     // This propagates the relation `var_live(V, P) :- var_used(V, P)`:
     var_live_var.insert(var_used.into());
@@ -163,10 +163,10 @@ where
         .collect()
 }
 
-pub(super) fn make_universal_region_live<Region: Atom, Point: Atom>(
-    region_live_at: &mut Vec<(Region, Point)>,
+pub(super) fn make_universal_region_live<Origin: Atom, Point: Atom>(
+    region_live_at: &mut Vec<(Origin, Point)>,
     cfg_edge: &[(Point, Point)],
-    universal_region: Vec<Region>,
+    universal_region: Vec<Origin>,
 ) {
     debug!("make_universal_regions_live()");
 
@@ -185,7 +185,7 @@ pub(super) fn make_universal_region_live<Region: Atom, Point: Atom>(
 }
 
 pub(super) fn init_region_live_at<
-    Region: Atom,
+    Origin: Atom,
     Loan: Atom,
     Point: Atom,
     Variable: Atom,
@@ -194,13 +194,13 @@ pub(super) fn init_region_live_at<
     var_used: Vec<(Variable, Point)>,
     var_drop_used: Vec<(Variable, Point)>,
     var_defined: Vec<(Variable, Point)>,
-    var_uses_region: Vec<(Variable, Region)>,
-    var_drops_region: Vec<(Variable, Region)>,
+    var_uses_region: Vec<(Variable, Origin)>,
+    var_drops_region: Vec<(Variable, Origin)>,
     var_maybe_initialized_on_exit: Vec<(Variable, Point)>,
     cfg_edge: &[(Point, Point)],
-    universal_region: Vec<Region>,
-    output: &mut Output<Region, Loan, Point, Variable, MovePath>,
-) -> Vec<(Region, Point)> {
+    universal_region: Vec<Origin>,
+    output: &mut Output<Origin, Loan, Point, Variable, MovePath>,
+) -> Vec<(Origin, Point)> {
     debug!("init_region_live_at()");
     let mut region_live_at = compute_live_regions(
         var_used,