Implement TSMT delete procedures

CHANGELOG.md

@@ -19,6 +19,9 @@
 - Allowed the assembler to produce programs with "phantom" calls (#1019).
 - Added `TraceLenSummary` struct which holds information about traces lengths to the `ExecutionTrace` (#1029).
 
+#### Stdlib
+- Completed `std::collections::smt` module by implementing `insert` and `set` procedures (#1036, #1038, #1046).
+
 ## 0.6.1 (2023-06-29)
 
 - Fixed `no-std` compilation for `miden-core`, `miden-assembly`, and `miden-processor` crates.

core/src/operations/decorators/advice.rs

@@ -167,6 +167,9 @@ pub enum AdviceInjector {
     ///   - Simple insert at depth 16: [d0, d1, ONE (is_simple_insert), ZERO (is_update)]
     ///   - Simple insert at depth 32 or 48: [d0, d1, ONE (is_simple_insert), ZERO (is_update), P_NODE]
     ///   - Complex insert: [f0, f1, ZERO (is_simple_insert), ZERO (is_update), E_KEY, E_VALUE]
+    ///   - Delete against an empty subtree: [d0, d1, ZERO (is_leaf), ONE (key_not_set)]
+    ///   - Delete against another leaf: [d0, d1, ONE (is_leaf), ONE (key_not_set), KEY, VALUE]
+    ///   - Delete against own leaf: [ZERO, ZERO, ZERO, ZERO (key_not_set), NEW_ROOT, OLD_VALUE]
     ///
     /// Where:
     /// - ROOT and NEW_ROOT are the roots of the TSMT before and after the insert respectively.

processor/src/advice/mod.rs

@@ -92,6 +92,12 @@ pub trait AdviceProvider {
     /// Returns an error if the value specified by the advice source cannot be obtained.
     fn push_stack(&mut self, source: AdviceSource) -> Result<(), ExecutionError>;
 
+    // ADVICE MAP
+    // --------------------------------------------------------------------------------------------
+
+    /// Returns a reference to the value(s) associated with the specified key in the advice map.
+    fn get_mapped_values(&self, key: &[u8; 32]) -> Option<&[Felt]>;
+
     /// Inserts the provided value into the advice map under the specified key.
     ///
     /// The values in the advice map can be moved onto the advice stack by invoking
@@ -101,13 +107,7 @@ pub trait AdviceProvider {
     /// are replaced with the specified values.
     fn insert_into_map(&mut self, key: Word, values: Vec<Felt>) -> Result<(), ExecutionError>;
 
-    // ADVICE MAP
-    // --------------------------------------------------------------------------------------------
-
-    /// Returns a reference to the value(s) associated with the specified key in the advice map.
-    fn get_mapped_values(&self, key: &[u8; 32]) -> Option<&[Felt]>;
-
-    // ADVISE SETS
+    // MERKLE STORE
     // --------------------------------------------------------------------------------------------
 
     /// Returns a node at the specified depth and index in a Merkle tree with the given root.
@@ -152,8 +152,23 @@ pub trait AdviceProvider {
         index: &Felt,
     ) -> Result<u8, ExecutionError>;
 
+    /// Returns node value and index of a leaf node in the subtree of the specified root, if and
+    /// only if this is the only leaf in the entire subtree. Otherwise, None is returned.
+    ///
+    /// The root itself is assumed to be located at the specified index in a tree with the provided
+    /// depth.
+    ///
+    /// # Errors
+    /// Returns an error if a three for the specified root does not exist in the advice provider.
+    fn find_lone_leaf(
+        &self,
+        root: Word,
+        root_index: NodeIndex,
+        tree_depth: u8,
+    ) -> Result<Option<(NodeIndex, Word)>, ExecutionError>;
+
     /// Updates a node at the specified depth and index in a Merkle tree with the specified root;
-    /// returns the Merkle path from the updated node to the new root.
+    /// returns the Merkle path from the updated node to the new root, together with the new root.
     ///
     /// The tree is cloned prior to the update. Thus, the advice provider retains the original and
     /// the updated tree.
@@ -171,7 +186,7 @@ pub trait AdviceProvider {
         depth: &Felt,
         index: &Felt,
         value: Word,
-    ) -> Result<MerklePath, ExecutionError>;
+    ) -> Result<(MerklePath, Word), ExecutionError>;
 
     /// Creates a new Merkle tree in the advice provider by combining Merkle trees with the
     /// specified roots. The root of the new tree is defined as `hash(left_root, right_root)`.
@@ -261,13 +276,22 @@ where
         T::get_leaf_depth(self, root, tree_depth, index)
     }
 
+    fn find_lone_leaf(
+        &self,
+        root: Word,
+        root_index: NodeIndex,
+        tree_depth: u8,
+    ) -> Result<Option<(NodeIndex, Word)>, ExecutionError> {
+        T::find_lone_leaf(self, root, root_index, tree_depth)
+    }
+
     fn update_merkle_node(
         &mut self,
         root: Word,
         depth: &Felt,
         index: &Felt,
         value: Word,
-    ) -> Result<MerklePath, ExecutionError> {
+    ) -> Result<(MerklePath, Word), ExecutionError> {
         T::update_merkle_node(self, root, depth, index, value)
     }
 

processor/src/advice/providers.rs

@@ -103,18 +103,19 @@ where
         Ok(())
     }
 
-    fn insert_into_map(&mut self, key: Word, values: Vec<Felt>) -> Result<(), ExecutionError> {
-        self.map.insert(key.into_bytes(), values);
-        Ok(())
-    }
-
     // ADVICE MAP
     // --------------------------------------------------------------------------------------------
+
     fn get_mapped_values(&self, key: &[u8; 32]) -> Option<&[Felt]> {
         self.map.get(key).map(|v| v.as_slice())
     }
 
-    // ADVISE SETS
+    fn insert_into_map(&mut self, key: Word, values: Vec<Felt>) -> Result<(), ExecutionError> {
+        self.map.insert(key.into_bytes(), values);
+        Ok(())
+    }
+
+    // MERKLE STORE
     // --------------------------------------------------------------------------------------------
 
     fn get_tree_node(
@@ -166,13 +167,25 @@ where
             .map_err(ExecutionError::MerkleStoreLookupFailed)
     }
 
+    fn find_lone_leaf(
+        &self,
+        root: Word,
+        root_index: NodeIndex,
+        tree_depth: u8,
+    ) -> Result<Option<(NodeIndex, Word)>, ExecutionError> {
+        self.store
+            .find_lone_leaf(root.into(), root_index, tree_depth)
+            .map(|leaf| leaf.map(|(index, leaf)| (index, leaf.into())))
+            .map_err(ExecutionError::MerkleStoreLookupFailed)
+    }
+
     fn update_merkle_node(
         &mut self,
         root: Word,
         depth: &Felt,
         index: &Felt,
         value: Word,
-    ) -> Result<MerklePath, ExecutionError> {
+    ) -> Result<(MerklePath, Word), ExecutionError> {
         let node_index = NodeIndex::from_elements(depth, index).map_err(|_| {
             ExecutionError::InvalidTreeNodeIndex {
                 depth: *depth,
@@ -181,7 +194,7 @@ where
         })?;
         self.store
             .set_node(root.into(), node_index, value.into())
-            .map(|root| root.path)
+            .map(|root| (root.path, root.root.into()))
             .map_err(ExecutionError::MerkleStoreUpdateFailed)
     }
 
@@ -289,7 +302,11 @@ impl AdviceProvider for MemAdviceProvider {
         self.provider.get_leaf_depth(root, tree_depth, index)
     }
 
-    fn update_merkle_node(&mut self, root: Word, depth: &Felt, index: &Felt, value: Word) -> Result<MerklePath, ExecutionError> {
+    fn find_lone_leaf(&self, root: Word, root_index: NodeIndex, tree_depth: u8) -> Result<Option<(NodeIndex, Word)>, ExecutionError> {
+        self.provider.find_lone_leaf(root, root_index, tree_depth)
+    }
+
+    fn update_merkle_node(&mut self, root: Word, depth: &Felt, index: &Felt, value: Word) -> Result<(MerklePath, Word), ExecutionError> {
         self.provider.update_merkle_node(root, depth, index, value)
     }
 
@@ -414,7 +431,11 @@ impl AdviceProvider for RecAdviceProvider {
         self.provider.get_leaf_depth(root, tree_depth, index)
     }
 
-    fn update_merkle_node(&mut self, root: Word, depth: &Felt, index: &Felt, value: Word) -> Result<MerklePath, ExecutionError> {
+    fn find_lone_leaf(&self, root: Word, root_index: NodeIndex, tree_depth: u8) -> Result<Option<(NodeIndex, Word)>, ExecutionError> {
+        self.provider.find_lone_leaf(root, root_index, tree_depth)
+    }
+
+    fn update_merkle_node(&mut self, root: Word, depth: &Felt, index: &Felt, value: Word) -> Result<(MerklePath, Word), ExecutionError> {
         self.provider.update_merkle_node(root, depth, index, value)
     }