Add results cursor

mir-state-analysis/src/free_pcs/check/checker.rs

@@ -6,36 +6,37 @@
 
 use prusti_rustc_interface::{
     data_structures::fx::FxHashMap,
-    dataflow::Results,
     middle::mir::{visit::Visitor, Location},
 };
 
 use crate::{
-    engine::FreePlaceCapabilitySummary, join_semi_lattice::RepackingJoinSemiLattice,
-    utils::PlaceRepacker, CapabilityKind, CapabilityLocal, CapabilitySummary, PlaceOrdering,
-    RepackOp,
+    utils::PlaceRepacker, CapabilityKind, CapabilityLocal, CapabilitySummary, Fpcs,
+    FreePcsAnalysis, PlaceOrdering, RepackOp,
 };
 
 use super::consistency::CapabilityConistency;
 
-pub(crate) fn check<'tcx>(results: Results<'tcx, FreePlaceCapabilitySummary<'_, 'tcx>>) {
-    let rp = results.analysis.0;
+pub(crate) fn check(mut results: FreePcsAnalysis<'_, '_>) {
+    let rp = results.repacker();
     let body = rp.body();
-    let mut cursor = results.into_results_cursor(body);
     for (block, data) in body.basic_blocks.iter_enumerated() {
-        cursor.seek_to_block_start(block);
-        let mut fpcs = cursor.get().clone();
+        let mut cursor = results.analysis_for_bb(block);
+        let mut fpcs = Fpcs {
+            summary: cursor.initial_state().clone(),
+            repackings: Vec::new(),
+            repacker: rp,
+        };
         // Consistency
         fpcs.summary.consistency_check(rp);
         for (statement_index, stmt) in data.statements.iter().enumerate() {
             let loc = Location {
                 block,
                 statement_index,
             };
-            cursor.seek_after_primary_effect(loc);
-            let fpcs_after = cursor.get();
+            let fpcs_after = cursor.next().unwrap();
+            assert_eq!(fpcs_after.location, loc);
             // Repacks
-            for op in &fpcs_after.repackings {
+            for op in fpcs_after.repacks {
                 op.update_free(&mut fpcs.summary, false, rp);
             }
             // Consistency
@@ -51,10 +52,10 @@ pub(crate) fn check<'tcx>(results: Results<'tcx, FreePlaceCapabilitySummary<'_,
             block,
             statement_index: data.statements.len(),
         };
-        cursor.seek_after_primary_effect(loc);
-        let fpcs_after = cursor.get();
+        let fpcs_after = cursor.next().unwrap();
+        assert_eq!(fpcs_after.location, loc);
         // Repacks
-        for op in &fpcs_after.repackings {
+        for op in fpcs_after.repacks {
             op.update_free(&mut fpcs.summary, false, rp);
         }
         // Consistency
@@ -65,19 +66,23 @@ pub(crate) fn check<'tcx>(results: Results<'tcx, FreePlaceCapabilitySummary<'_,
         assert!(fpcs.repackings.is_empty());
         // Consistency
         fpcs.summary.consistency_check(rp);
-        assert_eq!(&fpcs, fpcs_after);
+        assert_eq!(&fpcs.summary, fpcs_after.state);
 
-        for succ in data.terminator().successors() {
-            // Get repacks
-            let to = cursor.results().entry_set_for_block(succ);
-            let repacks = fpcs.summary.bridge(&to.summary, rp);
+        let Err(fpcs_end) = cursor.next() else {
+            panic!("Expected error at the end of the block");
+        };
 
+        for succ in fpcs_end.succs {
             // Repacks
             let mut from = fpcs.clone();
-            for op in repacks {
-                op.update_free(&mut from.summary, body.basic_blocks[succ].is_cleanup, rp);
+            for op in succ.repacks {
+                op.update_free(
+                    &mut from.summary,
+                    body.basic_blocks[succ.location.block].is_cleanup,
+                    rp,
+                );
             }
-            assert_eq!(&from, to);
+            assert_eq!(&from.summary, succ.state);
         }
     }
 }

mir-state-analysis/src/free_pcs/results/cursor.rs

@@ -0,0 +1,113 @@
+// © 2023, ETH Zurich
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use prusti_rustc_interface::{
+    dataflow::ResultsCursor,
+    middle::mir::{BasicBlock, Body, Location},
+};
+
+use crate::{
+    engine::FreePlaceCapabilitySummary, join_semi_lattice::RepackingJoinSemiLattice,
+    utils::PlaceRepacker, CapabilitySummary, RepackOp,
+};
+
+type Cursor<'mir, 'tcx> = ResultsCursor<'mir, 'tcx, FreePlaceCapabilitySummary<'mir, 'tcx>>;
+
+pub struct FreePcsAnalysis<'mir, 'tcx>(pub(crate) Cursor<'mir, 'tcx>);
+
+impl<'mir, 'tcx> FreePcsAnalysis<'mir, 'tcx> {
+    pub fn analysis_for_bb(&mut self, block: BasicBlock) -> FreePcsCursor<'_, 'mir, 'tcx> {
+        self.0.seek_to_block_start(block);
+        let end_stmt = self
+            .0
+            .analysis()
+            .0
+            .body()
+            .terminator_loc(block)
+            .successor_within_block();
+        FreePcsCursor {
+            analysis: self,
+            curr_stmt: Location {
+                block,
+                statement_index: 0,
+            },
+            end_stmt,
+        }
+    }
+
+    pub(crate) fn body(&self) -> &'mir Body<'tcx> {
+        self.0.analysis().0.body()
+    }
+    pub(crate) fn repacker(&self) -> PlaceRepacker<'mir, 'tcx> {
+        self.0.results().analysis.0
+    }
+}
+
+pub struct FreePcsCursor<'a, 'mir, 'tcx> {
+    analysis: &'a mut FreePcsAnalysis<'mir, 'tcx>,
+    curr_stmt: Location,
+    end_stmt: Location,
+}
+
+impl<'a, 'mir, 'tcx> FreePcsCursor<'a, 'mir, 'tcx> {
+    pub fn initial_state(&self) -> &CapabilitySummary<'tcx> {
+        &self.analysis.0.get().summary
+    }
+    pub fn next<'b>(
+        &'b mut self,
+    ) -> Result<FreePcsLocation<'b, 'tcx>, FreePcsTerminator<'b, 'tcx>> {
+        let location = self.curr_stmt;
+        assert!(location <= self.end_stmt);
+        self.curr_stmt = location.successor_within_block();
+
+        if location == self.end_stmt {
+            // TODO: cleanup
+            let cursor = &self.analysis.0;
+            let state = cursor.get();
+            let rp = self.analysis.repacker();
+            let block = &self.analysis.body()[location.block];
+            let succs = block
+                .terminator()
+                .successors()
+                .map(|succ| {
+                    // Get repacks
+                    let to = cursor.results().entry_set_for_block(succ);
+                    FreePcsLocation {
+                        location: Location {
+                            block: succ,
+                            statement_index: 0,
+                        },
+                        state: &to.summary,
+                        repacks: state.summary.bridge(&to.summary, rp),
+                    }
+                })
+                .collect();
+            Err(FreePcsTerminator { succs })
+        } else {
+            self.analysis.0.seek_after_primary_effect(location);
+            let state = self.analysis.0.get();
+            Ok(FreePcsLocation {
+                location,
+                state: &state.summary,
+                repacks: state.repackings.clone(),
+            })
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct FreePcsLocation<'a, 'tcx> {
+    pub location: Location,
+    /// Repacks before the statement
+    pub repacks: Vec<RepackOp<'tcx>>,
+    /// State after the statement
+    pub state: &'a CapabilitySummary<'tcx>,
+}
+
+#[derive(Debug)]
+pub struct FreePcsTerminator<'a, 'tcx> {
+    pub succs: Vec<FreePcsLocation<'a, 'tcx>>,
+}

mir-state-analysis/src/free_pcs/results/mod.rs

@@ -5,5 +5,7 @@
 // file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 mod repacks;
+mod cursor;
 
+pub use cursor::*;
 pub use repacks::*;

mir-state-analysis/src/lib.rs

@@ -18,11 +18,19 @@ use prusti_rustc_interface::{
     middle::{mir::Body, ty::TyCtxt},
 };
 
-pub fn test_free_pcs<'tcx>(mir: &Body<'tcx>, tcx: TyCtxt<'tcx>) {
+pub fn run_free_pcs<'mir, 'tcx>(
+    mir: &'mir Body<'tcx>,
+    tcx: TyCtxt<'tcx>,
+) -> FreePcsAnalysis<'mir, 'tcx> {
     let fpcs = free_pcs::engine::FreePlaceCapabilitySummary::new(tcx, mir);
     let analysis = fpcs
         .into_engine(tcx, mir)
         .pass_name("free_pcs")
         .iterate_to_fixpoint();
+    FreePcsAnalysis(analysis.into_results_cursor(mir))
+}
+
+pub fn test_free_pcs<'tcx>(mir: &Body<'tcx>, tcx: TyCtxt<'tcx>) {
+    let analysis = run_free_pcs(mir, tcx);
     free_pcs::check(analysis);
 }