blockifier: move execution utils logic to casm_estimation

Author: avivg-starkware

crates/blockifier/src/execution/casm_hash_estimation.rs

@@ -1,9 +1,13 @@
+use std::collections::HashMap;
 use std::ops::AddAssign;
 
+use cairo_vm::types::builtin_name::BuiltinName;
 use cairo_vm::vm::runners::cairo_runner::ExecutionResources;
 use starknet_api::contract_class::compiled_class_hash::HashVersion;
 use starknet_api::execution_resources::GasAmount;
 
+use crate::blockifier_versioned_constants::VersionedConstants;
+use crate::bouncer::vm_resources_to_sierra_gas;
 use crate::execution::contract_class::{
     EntryPointV1,
     EntryPointsByType,
@@ -204,3 +208,123 @@ impl EstimateCasmHashResources for CasmV2HashResourceEstimate {
         EstimatedExecutionResources::new(HashVersion::V2)
     }
 }
+
+// Constants used for estimating the cost of BLAKE hashing inside Starknet OS.
+// These values are based on empirical measurement by running
+// `encode_felt252_data_and_calc_blake_hash` on various combinations of big and small felts.
+mod blake_estimation {
+    // Per-felt step cost (measured).
+    pub const STEPS_BIG_FELT: usize = 45;
+    pub const STEPS_SMALL_FELT: usize = 15;
+
+    // One-time overhead.
+    // Overhead when input fills a full Blake message (16 u32s).
+    pub const BASE_STEPS_FULL_MSG: usize = 217;
+    // Overhead when input results in a partial message (remainder < 16 u32s).
+    pub const BASE_STEPS_PARTIAL_MSG: usize = 195;
+    // Extra steps per 2-u32 remainder in partial messages.
+    pub const STEPS_PER_2_U32_REMINDER: usize = 3;
+    // Overhead when input for `encode_felt252_data_and_calc_blake_hash` is non-empty.
+    pub const BASE_RANGE_CHECK_NON_EMPTY: usize = 3;
+    // Empty input steps.
+    pub const STEPS_EMPTY_INPUT: usize = 170;
+}
+
+fn base_steps_for_blake_hash(n_u32s: usize) -> usize {
+    let rem_u32s = n_u32s % FeltSizeCount::U32_WORDS_PER_MESSAGE;
+    if rem_u32s == 0 {
+        blake_estimation::BASE_STEPS_FULL_MSG
+    } else {
+        // This computation is based on running blake2s with different inputs.
+        // Note: all inputs expand to an even number of u32s --> `rem_u32s` is always even.
+        blake_estimation::BASE_STEPS_PARTIAL_MSG
+            + (rem_u32s / 2) * blake_estimation::STEPS_PER_2_U32_REMINDER
+    }
+}
+
+fn felts_steps(n_big_felts: usize, n_small_felts: usize) -> usize {
+    let big_steps = n_big_felts
+        .checked_mul(blake_estimation::STEPS_BIG_FELT)
+        .expect("Overflow computing big felt steps");
+    let small_steps = n_small_felts
+        .checked_mul(blake_estimation::STEPS_SMALL_FELT)
+        .expect("Overflow computing small felt steps");
+    big_steps.checked_add(small_steps).expect("Overflow computing total felt steps")
+}
+
+/// Estimates the number of VM steps needed to hash the given felts with Blake in Starknet OS.
+/// Each small felt unpacks into 2 u32s, and each big felt into 8 u32s.
+/// Adds a base cost depending on whether the total fits exactly into full 16-u32 messages.
+fn compute_blake_hash_steps(felt_size_groups: &FeltSizeCount) -> usize {
+    let total_u32s = felt_size_groups.encoded_u32_len();
+    if total_u32s == 0 {
+        // The empty input case is a special case.
+        return blake_estimation::STEPS_EMPTY_INPUT;
+    }
+
+    let base_steps = base_steps_for_blake_hash(total_u32s);
+    let felt_steps = felts_steps(felt_size_groups.large, felt_size_groups.small);
+
+    base_steps.checked_add(felt_steps).expect("Overflow computing total Blake hash steps")
+}
+
+/// Estimates resource usage for `encode_felt252_data_and_calc_blake_hash` in the Starknet OS.
+///
+/// # Encoding Details
+/// - Small felts → 2 `u32`s each; Big felts → 8 `u32`s each.
+/// - Each felt requires one `range_check` operation.
+///
+/// # Returns:
+/// - `ExecutionResources`: VM resource usage (e.g., n_steps, range checks).
+/// - `usize`: number of Blake opcodes used, accounted for separately as those are not reported via
+///   `ExecutionResources`.
+pub fn encode_and_blake_hash_resources(
+    felt_size_groups: &FeltSizeCount,
+) -> EstimatedExecutionResources {
+    let n_steps = compute_blake_hash_steps(felt_size_groups);
+    let builtin_instance_counter = match felt_size_groups.n_felts() {
+        // The empty case does not use builtins at all.
+        0 => HashMap::new(),
+        // One `range_check` per input felt to validate its size + Overhead for the non empty case.
+        _ => HashMap::from([(
+            BuiltinName::range_check,
+            felt_size_groups.n_felts() + blake_estimation::BASE_RANGE_CHECK_NON_EMPTY,
+        )]),
+    };
+
+    let resources = ExecutionResources { n_steps, n_memory_holes: 0, builtin_instance_counter };
+
+    EstimatedExecutionResources::V2Hash {
+        resources,
+        blake_count: felt_size_groups.blake_opcode_count(),
+    }
+}
+
+/// Converts the execution resources and blake opcode count to L2 gas.
+///
+/// Used for both Stwo ("proving_gas") and Stone ("sierra_gas") estimations, which differ in
+/// builtin costs. This unified logic is valid because only the `range_check` builtin is used,
+/// and its cost is identical across provers (see `bouncer.get_tx_weights`).
+// TODO(AvivG): Move inside blake estimation struct.
+pub fn blake_execution_resources_estimation_to_gas(
+    resources: EstimatedExecutionResources,
+    versioned_constants: &VersionedConstants,
+    blake_opcode_gas: usize,
+) -> GasAmount {
+    // TODO(AvivG): Remove this once gas computation is separated from resource estimation.
+    assert!(
+        resources
+            .resources()
+            .builtin_instance_counter
+            .keys()
+            .all(|&k| k == BuiltinName::range_check),
+        "Expected either empty builtins or only `range_check` builtin, got: {:?}. This breaks the \
+         assumption that builtin costs are identical between provers.",
+        resources.resources().builtin_instance_counter.keys().collect::<Vec<_>>()
+    );
+
+    resources.to_sierra_gas(
+        |resources| vm_resources_to_sierra_gas(resources, versioned_constants),
+        Some(blake_opcode_gas),
+    )
+}

crates/blockifier/src/execution/casm_hash_estimation_test.rs

@@ -1,10 +1,19 @@
 use std::collections::HashMap;
 
+use blake2s::encode_felts_to_u32s;
 use cairo_vm::types::builtin_name::BuiltinName;
 use cairo_vm::vm::runners::cairo_runner::ExecutionResources;
+use pretty_assertions::assert_eq;
 use rstest::rstest;
+use starknet_types_core::felt::Felt;
 
-use crate::execution::casm_hash_estimation::EstimatedExecutionResources;
+use crate::execution::casm_hash_estimation::blake_estimation::STEPS_EMPTY_INPUT;
+use crate::execution::casm_hash_estimation::{
+    compute_blake_hash_steps,
+    encode_and_blake_hash_resources,
+    EstimatedExecutionResources,
+};
+use crate::execution::contract_class::FeltSizeCount;
 
 impl EstimatedExecutionResources {
     /// Constructs an `EstimatedExecutionResources` for the V1 (Poseidon) hash function.
@@ -93,3 +102,36 @@ fn add_assign_estimated_resources_success(
         }
     }
 }
+
+#[test]
+fn test_u32_constants() {
+    // Small value < 2^63, will encode to 2 u32s.
+    let small_felt = Felt::ONE;
+    // Large value >= 2^63, will encode to 8 u32s (Just above 2^63).
+    let big_felt = Felt::from_hex_unchecked("8000000000000001");
+
+    let small_u32s = encode_felts_to_u32s(vec![small_felt]);
+    let big_u32s = encode_felts_to_u32s(vec![big_felt]);
+
+    // Blake estimation constants should match the actual encoding.
+    assert_eq!(small_u32s.len(), FeltSizeCount::U32_WORDS_PER_SMALL_FELT);
+    assert_eq!(big_u32s.len(), FeltSizeCount::U32_WORDS_PER_LARGE_FELT);
+}
+
+/// Test the edge case of hashing an empty array of felt values.
+#[test]
+fn test_zero_inputs() {
+    // logic was written.
+    let steps = compute_blake_hash_steps(&FeltSizeCount { large: 0, small: 0 });
+    assert_eq!(steps, STEPS_EMPTY_INPUT, "Unexpected base step cost for zero inputs");
+
+    // No opcodes should be emitted.
+    let opcodes = FeltSizeCount { large: 0, small: 0 }.blake_opcode_count();
+    assert_eq!(opcodes, 0, "Expected zero BLAKE opcodes for zero inputs");
+
+    // Should result in base cost only (no opcode cost).
+    let resources = encode_and_blake_hash_resources(&FeltSizeCount { large: 0, small: 0 });
+    let expected = ExecutionResources { n_steps: STEPS_EMPTY_INPUT, ..Default::default() };
+    assert_eq!(resources.resources(), &expected, "Unexpected resources values for zero-input hash");
+    assert_eq!(resources.blake_count(), 0, "Expected zero BLAKE opcodes for zero inputs");
+}

crates/blockifier/src/execution/contract_class.rs

@@ -42,14 +42,13 @@ use crate::abi::constants::{self};
 use crate::blockifier_versioned_constants::VersionedConstants;
 use crate::bouncer::vm_resources_to_sierra_gas;
 use crate::execution::call_info::BuiltinCounterMap;
-use crate::execution::entry_point::{EntryPointExecutionContext, EntryPointTypeAndSelector};
-use crate::execution::errors::PreExecutionError;
-use crate::execution::execution_utils::{
+use crate::execution::casm_hash_estimation::{
     blake_execution_resources_estimation_to_gas,
     encode_and_blake_hash_resources,
-    poseidon_hash_many_cost,
-    sn_api_to_cairo_vm_program,
 };
+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};
 #[cfg(feature = "cairo_native")]
 use crate::execution::native::contract_class::NativeCompiledClassV1;
 use crate::transaction::errors::TransactionExecutionError;

crates/blockifier/src/execution/execution_utils.rs

@@ -18,15 +18,11 @@ use cairo_vm::vm::vm_core::VirtualMachine;
 use num_bigint::BigUint;
 use starknet_api::core::ClassHash;
 use starknet_api::deprecated_contract_class::Program as DeprecatedProgram;
-use starknet_api::execution_resources::GasAmount;
 use starknet_api::transaction::fields::Calldata;
 use starknet_types_core::felt::Felt;
 
-use crate::blockifier_versioned_constants::VersionedConstants;
-use crate::bouncer::vm_resources_to_sierra_gas;
 use crate::execution::call_info::{CallExecution, CallInfo, Retdata};
-use crate::execution::casm_hash_estimation::EstimatedExecutionResources;
-use crate::execution::contract_class::{FeltSizeCount, RunnableCompiledClass, TrackedResource};
+use crate::execution::contract_class::{RunnableCompiledClass, TrackedResource};
 use crate::execution::entry_point::{
     execute_constructor_entry_point,
     ConstructorContext,
@@ -372,123 +368,3 @@ pub fn poseidon_hash_many_cost(data_length: usize) -> ExecutionResources {
         builtin_instance_counter: HashMap::from([(BuiltinName::poseidon, data_length / 2 + 1)]),
     }
 }
-
-// Constants used for estimating the cost of BLAKE hashing inside Starknet OS.
-// These values are based on empirical measurement by running
-// `encode_felt252_data_and_calc_blake_hash` on various combinations of big and small felts.
-mod blake_estimation {
-    // Per-felt step cost (measured).
-    pub const STEPS_BIG_FELT: usize = 45;
-    pub const STEPS_SMALL_FELT: usize = 15;
-
-    // One-time overhead.
-    // Overhead when input fills a full Blake message (16 u32s).
-    pub const BASE_STEPS_FULL_MSG: usize = 217;
-    // Overhead when input results in a partial message (remainder < 16 u32s).
-    pub const BASE_STEPS_PARTIAL_MSG: usize = 195;
-    // Extra steps per 2-u32 remainder in partial messages.
-    pub const STEPS_PER_2_U32_REMINDER: usize = 3;
-    // Overhead when input for `encode_felt252_data_and_calc_blake_hash` is non-empty.
-    pub const BASE_RANGE_CHECK_NON_EMPTY: usize = 3;
-    // Empty input steps.
-    pub const STEPS_EMPTY_INPUT: usize = 170;
-}
-
-fn base_steps_for_blake_hash(n_u32s: usize) -> usize {
-    let rem_u32s = n_u32s % FeltSizeCount::U32_WORDS_PER_MESSAGE;
-    if rem_u32s == 0 {
-        blake_estimation::BASE_STEPS_FULL_MSG
-    } else {
-        // This computation is based on running blake2s with different inputs.
-        // Note: all inputs expand to an even number of u32s --> `rem_u32s` is always even.
-        blake_estimation::BASE_STEPS_PARTIAL_MSG
-            + (rem_u32s / 2) * blake_estimation::STEPS_PER_2_U32_REMINDER
-    }
-}
-
-fn felts_steps(n_big_felts: usize, n_small_felts: usize) -> usize {
-    let big_steps = n_big_felts
-        .checked_mul(blake_estimation::STEPS_BIG_FELT)
-        .expect("Overflow computing big felt steps");
-    let small_steps = n_small_felts
-        .checked_mul(blake_estimation::STEPS_SMALL_FELT)
-        .expect("Overflow computing small felt steps");
-    big_steps.checked_add(small_steps).expect("Overflow computing total felt steps")
-}
-
-/// Estimates the number of VM steps needed to hash the given felts with Blake in Starknet OS.
-/// Each small felt unpacks into 2 u32s, and each big felt into 8 u32s.
-/// Adds a base cost depending on whether the total fits exactly into full 16-u32 messages.
-fn compute_blake_hash_steps(felt_size_groups: &FeltSizeCount) -> usize {
-    let total_u32s = felt_size_groups.encoded_u32_len();
-    if total_u32s == 0 {
-        // The empty input case is a special case.
-        return blake_estimation::STEPS_EMPTY_INPUT;
-    }
-
-    let base_steps = base_steps_for_blake_hash(total_u32s);
-    let felt_steps = felts_steps(felt_size_groups.large, felt_size_groups.small);
-
-    base_steps.checked_add(felt_steps).expect("Overflow computing total Blake hash steps")
-}
-
-/// Estimates resource usage for `encode_felt252_data_and_calc_blake_hash` in the Starknet OS.
-///
-/// # Encoding Details
-/// - Small felts → 2 `u32`s each; Big felts → 8 `u32`s each.
-/// - Each felt requires one `range_check` operation.
-///
-/// # Returns:
-/// - `ExecutionResources`: VM resource usage (e.g., n_steps, range checks).
-/// - `usize`: number of Blake opcodes used, accounted for separately as those are not reported via
-///   `ExecutionResources`.
-pub fn encode_and_blake_hash_resources(
-    felt_size_groups: &FeltSizeCount,
-) -> EstimatedExecutionResources {
-    let n_steps = compute_blake_hash_steps(felt_size_groups);
-    let builtin_instance_counter = match felt_size_groups.n_felts() {
-        // The empty case does not use builtins at all.
-        0 => HashMap::new(),
-        // One `range_check` per input felt to validate its size + Overhead for the non empty case.
-        _ => HashMap::from([(
-            BuiltinName::range_check,
-            felt_size_groups.n_felts() + blake_estimation::BASE_RANGE_CHECK_NON_EMPTY,
-        )]),
-    };
-
-    let resources = ExecutionResources { n_steps, n_memory_holes: 0, builtin_instance_counter };
-
-    EstimatedExecutionResources::V2Hash {
-        resources,
-        blake_count: felt_size_groups.blake_opcode_count(),
-    }
-}
-
-/// Converts the execution resources and blake opcode count to L2 gas.
-///
-/// Used for both Stwo ("proving_gas") and Stone ("sierra_gas") estimations, which differ in
-/// builtin costs. This unified logic is valid because only the `range_check` builtin is used,
-/// and its cost is identical across provers (see `bouncer.get_tx_weights`).
-// TODO(AvivG): Move inside blake estimation struct.
-pub fn blake_execution_resources_estimation_to_gas(
-    resources: EstimatedExecutionResources,
-    versioned_constants: &VersionedConstants,
-    blake_opcode_gas: usize,
-) -> GasAmount {
-    // TODO(AvivG): Remove this once gas computation is separated from resource estimation.
-    assert!(
-        resources
-            .resources()
-            .builtin_instance_counter
-            .keys()
-            .all(|&k| k == BuiltinName::range_check),
-        "Expected either empty builtins or only `range_check` builtin, got: {:?}. This breaks the \
-         assumption that builtin costs are identical between provers.",
-        resources.resources().builtin_instance_counter.keys().collect::<Vec<_>>()
-    );
-
-    resources.to_sierra_gas(
-        |resources| vm_resources_to_sierra_gas(resources, versioned_constants),
-        Some(blake_opcode_gas),
-    )
-}