Stopped updating snap-refs - and only introducing top level. (#8048)

Author: orizi

crates/cairo-lang-lowering/src/borrow_check/test_data/closure

@@ -341,11 +341,12 @@ Statements:
   (v9: core::integer::u32) <- 2
   (v10: (core::integer::u32,)) <- struct_construct(v9{`2`})
   (v11: core::integer::u32) <- Generated `core::ops::function::Fn::call` for {[email protected]:3:13: 3:16}(v8{`c`}, v10{`c(2)`})
-  (v12: core::integer::u32) <- 0
-  (v13: @core::felt252) <- core::ops::index::DeprecatedIndexViewImpl::<core::array::Array::<core::felt252>, core::integer::u32, @core::felt252, core::array::ArrayIndex::<core::felt252>>::index(v5{`x`}, v12{`0`})
-  (v14: core::felt252) <- desnap(v13{`0`})
+  (v12: core::array::Array::<core::felt252>, v13: @core::array::Array::<core::felt252>) <- snapshot(v4{`x`})
+  (v14: core::integer::u32) <- 0
+  (v15: @core::felt252) <- core::ops::index::DeprecatedIndexViewImpl::<core::array::Array::<core::felt252>, core::integer::u32, @core::felt252, core::array::ArrayIndex::<core::felt252>>::index(v13{`x`}, v14{`0`})
+  (v16: core::felt252) <- desnap(v15{`0`})
 End:
-  Return(v14)
+  Return(v16)
 
 //! > ==========================================================================
 

crates/cairo-lang-lowering/src/lower/block_builder.rs

@@ -24,9 +24,9 @@ use crate::{Block, BlockEnd, BlockId, MatchInfo, Statement, VarRemapping, VarUsa
 #[derive(Clone)]
 pub struct BlockBuilder {
     /// A store for semantic variables, owning their OwnedVariable instances.
-    pub semantics: SemanticLoweringMapping,
+    semantics: SemanticLoweringMapping,
     /// The semantic variables that are captured as snapshots in this block.
-    pub snapped_semantics: OrderedHashMap<MemberPath, VariableId>,
+    snapped_semantics: OrderedHashMap<MemberPath, VariableId>,
     /// The semantic variables that are added/changed in this block.
     changed_member_paths: OrderedHashSet<MemberPath>,
     /// Current sequence of lowered statements emitted.
@@ -92,8 +92,6 @@ impl BlockBuilder {
         var: VariableId,
         location: LocationId,
     ) {
-        // Invalidate snapshot to the given memberpath.
-        self.snapped_semantics.swap_remove(&member_path);
         self.semantics.update(
             &mut BlockStructRecomposer { statements: &mut self.statements, ctx, location },
             &member_path,
@@ -125,9 +123,14 @@ impl BlockBuilder {
             .map(|var_id| VarUsage { var_id, location })
     }
 
-    /// Updates the reference of a semantic variable to a snapshot of its lowered variable.
-    pub fn update_snap_ref(&mut self, member_path: &ExprVarMemberPath, var: VariableId) {
-        self.snapped_semantics.insert(member_path.into(), var);
+    /// Introduces a semantic variable as the representation of the given member path.
+    pub fn introduce(&mut self, member_path: MemberPath, var: VariableId) {
+        self.semantics.introduce(member_path, var);
+    }
+
+    /// Introduces a semantic variable as the representation of the given member path as a snapshot.
+    pub fn introduce_snap(&mut self, member_path: MemberPath, var: VariableId) {
+        self.snapped_semantics.insert(member_path, var);
     }
 
     /// Gets the reference of a snapshot of semantic variable, possibly by deconstructing its

crates/cairo-lang-lowering/src/lower/context.rs

@@ -282,10 +282,7 @@ impl LoweredExpr {
                 let (original, snapshot) =
                     generators::Snapshot { input, location }.add(ctx, &mut builder.statements);
                 if let LoweredExpr::Member(member_path, _location) = &*expr {
-                    // `update_ref` invalidates snapshots so it must be called before
-                    // `update_snap_ref`.
                     builder.update_ref(ctx, member_path, original);
-                    builder.update_snap_ref(member_path, snapshot);
                 }
 
                 Ok(VarUsage { var_id: snapshot, location })

crates/cairo-lang-lowering/src/lower/mod.rs

@@ -411,9 +411,9 @@ pub fn lower_loop_function(
             let location = ctx.get_location(param.stable_ptr().untyped());
             let var = ctx.new_var(VarRequest { ty: param.ty(), location });
             if snapped_params.contains_key::<MemberPath>(&(&param).into()) {
-                builder.update_snap_ref(&param, var)
+                builder.introduce_snap((&param).into(), var)
             } else {
-                builder.semantics.introduce((&param).into(), var);
+                builder.introduce((&param).into(), var);
             }
             var
         })
@@ -1890,7 +1890,7 @@ fn get_destruct_lowering(
         .into_iter()
         .map(|param| {
             let var = ctx.new_var(VarRequest { ty: param.ty(), location: location_id });
-            builder.semantics.introduce((&param).into(), var);
+            builder.introduce((&param).into(), var);
             var
         })
         .collect_vec();
@@ -2001,12 +2001,10 @@ fn add_closure_call_function(
     }
     .add(&mut ctx, &mut builder.statements);
     for (i, (param, _)) in closure_info.members.iter().enumerate() {
-        builder.semantics.introduce(param.clone(), captured_vars[i]);
+        builder.introduce(param.clone(), captured_vars[i]);
     }
     for (i, (param, _)) in closure_info.snapshots.iter().enumerate() {
-        builder
-            .snapped_semantics
-            .insert(param.clone(), captured_vars[i + closure_info.members.len()]);
+        builder.introduce_snap(param.clone(), captured_vars[i + closure_info.members.len()]);
     }
     let param_vars = generators::StructDestructure {
         input: VarUsage { var_id: parameters[1], location: expr_location },
@@ -2018,7 +2016,7 @@ fn add_closure_call_function(
     }
     .add(&mut ctx, &mut builder.statements);
     for (param_var, param) in param_vars.into_iter().zip(expr.params.iter()) {
-        builder.semantics.introduce((&parameter_as_member_path(param.clone())).into(), param_var);
+        builder.introduce((&parameter_as_member_path(param.clone())).into(), param_var);
         ctx.semantic_defs
             .insert(semantic::VarId::Param(param.id), semantic::Binding::Param(param.clone()));
     }

crates/cairo-lang-lowering/src/lower/test_data/loop

@@ -580,21 +580,22 @@ End:
 
 blk3:
 Statements:
-  (v13: core::felt252) <- 10
-  (v14: core::felt252, v15: @core::felt252) <- snapshot(v13)
-  (v16: core::bool) <- core::Felt252PartialEq::eq(v4, v15)
+  (v13: core::felt252, v14: @core::felt252) <- snapshot(v3)
+  (v15: core::felt252) <- 10
+  (v16: core::felt252, v17: @core::felt252) <- snapshot(v15)
+  (v18: core::bool) <- core::Felt252PartialEq::eq(v14, v17)
 End:
-  Match(match_enum(v16) {
-    bool::False(v20) => blk5,
-    bool::True(v17) => blk4,
+  Match(match_enum(v18) {
+    bool::False(v22) => blk5,
+    bool::True(v19) => blk4,
   })
 
 blk4:
 Statements:
-  (v18: ()) <- struct_construct()
-  (v19: core::bool) <- bool::True(v18)
+  (v20: ()) <- struct_construct()
+  (v21: core::bool) <- bool::True(v20)
 End:
-  Return(v2, v19)
+  Return(v2, v21)
 
 blk5:
 Statements:
@@ -603,9 +604,9 @@ End:
 
 blk6:
 Statements:
-  (v22: core::felt252, v21: core::bool) <- test::foo[38-201](v2)
+  (v24: core::felt252, v23: core::bool) <- test::foo[38-201](v2)
 End:
-  Return(v22, v21)
+  Return(v24, v23)
 
 
 Final lowering:
@@ -1735,21 +1736,22 @@ End:
 
 blk3:
 Statements:
-  (v14: core::felt252) <- 5
-  (v15: core::felt252, v16: @core::felt252) <- snapshot(v14)
-  (v17: core::bool) <- core::Felt252PartialEq::eq(v4, v16)
+  (v14: core::felt252, v15: @core::felt252) <- snapshot(v3)
+  (v16: core::felt252) <- 5
+  (v17: core::felt252, v18: @core::felt252) <- snapshot(v16)
+  (v19: core::bool) <- core::Felt252PartialEq::eq(v15, v18)
 End:
-  Match(match_enum(v17) {
-    bool::False(v21) => blk5,
-    bool::True(v18) => blk4,
+  Match(match_enum(v19) {
+    bool::False(v23) => blk5,
+    bool::True(v20) => blk4,
   })
 
 blk4:
 Statements:
-  (v19: core::integer::u32) <- 5
-  (v20: core::internal::LoopResult::<core::bool, core::integer::u32>) <- LoopResult::EarlyReturn(v19)
+  (v21: core::integer::u32) <- 5
+  (v22: core::internal::LoopResult::<core::bool, core::integer::u32>) <- LoopResult::EarlyReturn(v21)
 End:
-  Return(v2, v20)
+  Return(v2, v22)
 
 blk5:
 Statements:
@@ -1758,20 +1760,21 @@ End:
 
 blk6:
 Statements:
-  (v22: core::felt252) <- 3
-  (v23: core::felt252, v24: @core::felt252) <- snapshot(v22)
-  (v25: core::bool) <- core::Felt252PartialEq::eq(v4, v24)
+  (v24: core::felt252, v25: @core::felt252) <- snapshot(v14)
+  (v26: core::felt252) <- 3
+  (v27: core::felt252, v28: @core::felt252) <- snapshot(v26)
+  (v29: core::bool) <- core::Felt252PartialEq::eq(v25, v28)
 End:
-  Match(match_enum(v25) {
-    bool::False(v29) => blk8,
-    bool::True(v26) => blk7,
+  Match(match_enum(v29) {
+    bool::False(v33) => blk8,
+    bool::True(v30) => blk7,
   })
 
 blk7:
 Statements:
-  (v28: core::felt252, v27: core::internal::LoopResult::<core::bool, core::integer::u32>) <- test::foo[37-253](v2)
+  (v32: core::felt252, v31: core::internal::LoopResult::<core::bool, core::integer::u32>) <- test::foo[37-253](v2)
 End:
-  Return(v28, v27)
+  Return(v32, v31)
 
 blk8:
 Statements:
@@ -1780,9 +1783,9 @@ End:
 
 blk9:
 Statements:
-  (v31: core::felt252, v30: core::internal::LoopResult::<core::bool, core::integer::u32>) <- test::foo[37-253](v2)
+  (v35: core::felt252, v34: core::internal::LoopResult::<core::bool, core::integer::u32>) <- test::foo[37-253](v2)
 End:
-  Return(v31, v30)
+  Return(v35, v34)
 
 
 Final lowering:
@@ -2242,37 +2245,38 @@ End:
 
 blk5:
 Statements:
-  (v15: core::internal::LoopResult::<(), core::integer::u32>) <- test::foo[127-237](v6)
+  (v15: core::integer::u32, v16: @core::integer::u32) <- snapshot(v5)
+  (v17: core::internal::LoopResult::<(), core::integer::u32>) <- test::foo[127-237](v16)
 End:
-  Match(match_enum(v15) {
-    LoopResult::Normal(v16) => blk6,
-    LoopResult::EarlyReturn(v17) => blk7,
+  Match(match_enum(v17) {
+    LoopResult::Normal(v18) => blk6,
+    LoopResult::EarlyReturn(v19) => blk7,
   })
 
 blk6:
 Statements:
 End:
-  Goto(blk8, {v16 -> v19})
+  Goto(blk8, {v18 -> v21})
 
 blk7:
 Statements:
-  (v18: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v17)
+  (v20: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v19)
 End:
-  Return(v2, v18)
+  Return(v2, v20)
 
 blk8:
 Statements:
-  (v20: core::integer::u32) <- 6
-  (v21: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v20)
+  (v22: core::integer::u32) <- 6
+  (v23: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v22)
 End:
-  Return(v2, v21)
+  Return(v2, v23)
 
 blk9:
 Statements:
-  (v22: ()) <- struct_construct()
-  (v23: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::Normal(v22)
+  (v24: ()) <- struct_construct()
+  (v25: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::Normal(v24)
 End:
-  Return(v2, v23)
+  Return(v2, v25)
 
 
 Final lowering:
@@ -2578,37 +2582,38 @@ End:
 
 blk5:
 Statements:
-  (v15: core::internal::LoopResult::<(), core::integer::u32>) <- test::foo[127-237](v6)
+  (v15: core::integer::u32, v16: @core::integer::u32) <- snapshot(v5)
+  (v17: core::internal::LoopResult::<(), core::integer::u32>) <- test::foo[127-237](v16)
 End:
-  Match(match_enum(v15) {
-    LoopResult::Normal(v16) => blk6,
-    LoopResult::EarlyReturn(v17) => blk7,
+  Match(match_enum(v17) {
+    LoopResult::Normal(v18) => blk6,
+    LoopResult::EarlyReturn(v19) => blk7,
   })
 
 blk6:
 Statements:
 End:
-  Goto(blk8, {v16 -> v19})
+  Goto(blk8, {v18 -> v21})
 
 blk7:
 Statements:
-  (v18: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v17)
+  (v20: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v19)
 End:
-  Return(v2, v18)
+  Return(v2, v20)
 
 blk8:
 Statements:
-  (v20: core::integer::u32) <- 6
-  (v21: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v20)
+  (v22: core::integer::u32) <- 6
+  (v23: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::EarlyReturn(v22)
 End:
-  Return(v2, v21)
+  Return(v2, v23)
 
 blk9:
 Statements:
-  (v22: ()) <- struct_construct()
-  (v23: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::Normal(v22)
+  (v24: ()) <- struct_construct()
+  (v25: core::internal::LoopResult::<(), core::integer::u32>) <- LoopResult::Normal(v24)
 End:
-  Return(v2, v23)
+  Return(v2, v25)
 
 
 Final lowering: