blockifier: add estimate_casm_blake_hash_computation_resources (#7212)

Author: avivg-starkware

crates/blockifier/src/execution/contract_class.rs

@@ -34,7 +34,11 @@ use starknet_types_core::felt::Felt;
 use crate::abi::constants::{self};
 use crate::execution::entry_point::{EntryPointExecutionContext, EntryPointTypeAndSelector};
 use crate::execution::errors::PreExecutionError;
-use crate::execution::execution_utils::{poseidon_hash_many_cost, sn_api_to_cairo_vm_program};
+use crate::execution::execution_utils::{
+    cost_of_encode_felt252_data_and_calc_blake_hash,
+    poseidon_hash_many_cost,
+    sn_api_to_cairo_vm_program,
+};
 #[cfg(feature = "cairo_native")]
 use crate::execution::native::contract_class::NativeCompiledClassV1;
 use crate::transaction::errors::TransactionExecutionError;
@@ -287,7 +291,7 @@ impl CompiledClassV1 {
     /// This is an empiric measurement of several bytecode lengths, which constitutes as the
     /// dominant factor in it.
     fn estimate_casm_hash_computation_resources(&self) -> ExecutionResources {
-        estimate_casm_hash_computation_resources(&self.bytecode_segment_lengths)
+        estimate_casm_poseidon_hash_computation_resources(&self.bytecode_segment_lengths)
     }
 
     /// Estimate the VM gas required to perform a CompiledClassHash migration,
@@ -321,7 +325,7 @@ impl CompiledClassV1 {
 ///
 /// Note: the function focuses on the bytecode size, and currently ignores the cost handling the
 /// class entry points.
-pub fn estimate_casm_hash_computation_resources(
+pub fn estimate_casm_poseidon_hash_computation_resources(
     bytecode_segment_lengths: &NestedIntList,
 ) -> ExecutionResources {
     // The constants in this function were computed by running the Casm code on a few values
@@ -361,6 +365,80 @@ pub fn estimate_casm_hash_computation_resources(
     }
 }
 
+/// Cost to hash a single flat segment of `len` felts.
+fn leaf_cost<F>(len: usize, resources_to_gas_fn: F) -> GasAmount
+where
+    F: Fn(&ExecutionResources) -> GasAmount,
+{
+    // All `len` inputs treated as “big” felts; no small-felt optimization here.
+    cost_of_encode_felt252_data_and_calc_blake_hash(len, 0, resources_to_gas_fn)
+}
+
+/// Cost to hash a multi-segment contract:
+fn node_cost<F>(segs: &[NestedIntList], resources_to_gas_fn: F) -> GasAmount
+where
+    F: Fn(&ExecutionResources) -> GasAmount,
+{
+    // TODO(AvivG): Add base estimation for node.
+    let mut gas = GasAmount::ZERO;
+
+    // TODO(AvivG): Add base estimation of each segment. Could this be part of 'leaf_cost'?
+    let segment_overhead = GasAmount::ZERO;
+
+    // For each segment, hash its felts.
+    for seg in segs {
+        match seg {
+            NestedIntList::Leaf(len) => {
+                gas = gas.checked_add_panic_on_overflow(segment_overhead);
+                gas = gas.checked_add_panic_on_overflow(leaf_cost(*len, &resources_to_gas_fn));
+            }
+            _ => panic!("Estimating hash cost only supports at most one level of segmentation."),
+        }
+    }
+
+    // Node‐level hash over (hash1, len1, hash2, len2, …): one segment hash (“big” felt))
+    // and one segment length (“small” felt) per segment.
+    let node_hash_cost = cost_of_encode_felt252_data_and_calc_blake_hash(
+        segs.len(),
+        segs.len(),
+        resources_to_gas_fn,
+    );
+
+    gas.checked_add_panic_on_overflow(node_hash_cost)
+}
+
+/// Estimates the VM resources to compute the CASM Blake hash for a Cairo-1 contract:
+/// - Uses only bytecode size (treats all felts as “big”, ignores the small-felt optimization).
+pub fn estimate_casm_blake_hash_computation_resources<F>(
+    bytecode_segment_lengths: &NestedIntList,
+    resources_to_gas_fn: F,
+) -> GasAmount
+where
+    F: Fn(&ExecutionResources) -> GasAmount,
+{
+    // TODO(AvivG): Currently ignores entry-point hashing costs.
+    // TODO(AvivG): Missing base overhead estimation for compiled_class_hash.
+
+    // Basic frame overhead.
+    // TODO(AvivG): Once compiled_class_hash estimation is complete,
+    // revisit whether this should be moved into cost_of_encode_felt252_data_and_calc_blake_hash.
+    let resources = ExecutionResources {
+        n_steps: 0,
+        n_memory_holes: 0,
+        builtin_instance_counter: HashMap::from([(BuiltinName::range_check, 3)]),
+    };
+    let gas = resources_to_gas_fn(&resources);
+
+    // Add leaf vs node cost
+    let added_gas = match bytecode_segment_lengths {
+        // Single-segment contract (e.g., older Sierra contracts).
+        NestedIntList::Leaf(len) => leaf_cost(*len, &resources_to_gas_fn),
+        NestedIntList::Node(segs) => node_cost(segs, resources_to_gas_fn),
+    };
+
+    gas.checked_add_panic_on_overflow(added_gas)
+}
+
 // Returns the set of segments that were visited according to the given visited PCs and segment
 // lengths.
 // Each visited segment must have its starting PC visited, and is represented by it.

crates/native_blockifier/src/py_testing_wrappers.rs

@@ -1,4 +1,4 @@
-use blockifier::execution::contract_class::estimate_casm_hash_computation_resources;
+use blockifier::execution::contract_class::estimate_casm_poseidon_hash_computation_resources;
 use blockifier::transaction::errors::{TransactionExecutionError, TransactionFeeError};
 use cairo_lang_starknet_classes::NestedIntList;
 use pyo3::{pyfunction, PyResult};
@@ -14,17 +14,17 @@ pub fn raise_error_for_testing() -> NativeBlockifierResult<()> {
     .into())
 }
 
-/// Wrapper for [estimate_casm_hash_computation_resources] that can be used for testing.
+/// Wrapper for [estimate_casm_poseidon_hash_computation_resources] that can be used for testing.
 /// Takes a leaf.
 #[pyfunction]
 pub fn estimate_casm_hash_computation_resources_for_testing_single(
     bytecode_segment_lengths: usize,
 ) -> PyResult<PyExecutionResources> {
     let node = NestedIntList::Leaf(bytecode_segment_lengths);
-    Ok(estimate_casm_hash_computation_resources(&node).into())
+    Ok(estimate_casm_poseidon_hash_computation_resources(&node).into())
 }
 
-/// Wrapper for [estimate_casm_hash_computation_resources] that can be used for testing.
+/// Wrapper for [estimate_casm_poseidon_hash_computation_resources] that can be used for testing.
 /// Takes a node of leaves.
 #[pyfunction]
 pub fn estimate_casm_hash_computation_resources_for_testing_list(
@@ -33,5 +33,5 @@ pub fn estimate_casm_hash_computation_resources_for_testing_list(
     let node = NestedIntList::Node(
         bytecode_segment_lengths.into_iter().map(NestedIntList::Leaf).collect(),
     );
-    Ok(estimate_casm_hash_computation_resources(&node).into())
+    Ok(estimate_casm_poseidon_hash_computation_resources(&node).into())
 }