starknet_os: recompute and assert the blake constants

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• starknet_os: recompute and assert the blake constants #14032 : 2 dependent PRs (#14033 , #14035 ) 👈 (View in Graphite)
• blockifier: fix blake estimation offset by fixing constants #14034
• starknet_os: move blake constants to struct scope #14031
• starknet_os: extract cairo blake run to function #14030
• main

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PR Summary

Medium Risk
Test-only change, but it hard-codes empiric Cairo VM step counts and derived deltas, which may become brittle across Cairo program/toolchain/layout changes and cause CI failures.

Overview
Adds a new test_blake_step_constants in blake2s_test.rs that empirically measures Cairo VM step counts for encode_felt252_data_and_calc_blake_hash and asserts they match CasmV2HashResourceEstimate constants (empty-input base cost, per-felt costs, full-message base overhead, and partial-message remainder overhead).

Introduces a small helper (cairo_encode_felt252_data_and_calc_blake_hash_steps) to simplify extracting n_steps from the Cairo runner results.

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Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on AvivYossef-starkware and Yoni-Starkware).

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crates/blockifier/src/execution/casm_hash_estimation.rs line 266 at r1 (raw file):

    pub const BASE_STEPS_PARTIAL_MSG: usize = 195;
    // Extra VM steps added per 2-u32 remainder in partial Blake messages.
    pub const STEPS_PER_2_U32_REMINDER: usize = 3;

all 6 constants are tested, 3 needed a one-step adjustment

Code quote:

    // Base number of VM steps applied when the input to Blake hashing is empty.
    // Determined empirically by running `encode_felt252_data_and_calc_blake_hash` on empty input.
    pub const STEPS_EMPTY_INPUT: usize = 170;

    // The constants used are empirical, based on running `encode_felt252_data_and_calc_blake_hash`
    // on combinations of large and small felts.
    // VM steps per large felt.
    pub const STEPS_PER_LARGE_FELT: usize = 45;
    // VM steps per small felt.
    pub const STEPS_PER_SMALL_FELT: usize = 15;
    // Base overhead when input exactly fills a 16-u32 Blake message.
    pub const BASE_STEPS_FULL_MSG: usize = 217;
    // Base overhead when the input leaves a remainder (< 16 u32s) for a Blake message.
    pub const BASE_STEPS_PARTIAL_MSG: usize = 195;
    // Extra VM steps added per 2-u32 remainder in partial Blake messages.
    pub const STEPS_PER_2_U32_REMINDER: usize = 3;

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