chore(l2): cache precaculated hashes for an in memory trie

[xqft]

Motivation

The prover's guest program takes as input a list of RLP encoded nodes, hashes them and later rebuilds the trie using from_nodes(), but this function does not cache the hashes already calculated, leading to double hashing.

This cuts calls of compute_hash by half (some remain because of new nodes that appear when modifying the state trie after block execution).

flamegraphs:
before:

after:

Proving time diffs:

[Copilot]

Pull Request Overview

This PR optimizes trie construction by caching pre-calculated hashes to avoid redundant hash computations during trie rebuilding from RLP-encoded nodes.

• Introduces a with_hash method to NodeRef that allows setting pre-calculated hashes
• Updates from_nodes method to use cached hashes when available instead of recomputing them
• Reduces hash computation overhead by approximately half according to flamegraph analysis

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
crates/common/trie/node.rs	Adds with_hash method to NodeRef for setting pre-calculated hashes
crates/common/trie/trie.rs	Updates trie construction to use cached hashes via the new with_hash method

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[github-actions]

Benchmark for f9320f6

Click to view benchmark

Test	Base	PR	%
Trie/cita-trie insert 10k	35.8±0.46ms	35.2±0.66ms	-1.68%
Trie/cita-trie insert 1k	3.6±0.02ms	3.6±0.11ms	0.00%
Trie/ethrex-trie insert 10k	56.0±0.38ms	54.6±0.53ms	-2.50%
Trie/ethrex-trie insert 1k	6.2±0.04ms	6.1±0.02ms	-1.61%

[github-actions]

Lines of code report

Total lines added: 13
Total lines removed: 0
Total lines changed: 13

Detailed view

+-----------------------------------+-------+------+
| File                              | Lines | Diff |
+-----------------------------------+-------+------+
| ethrex/crates/common/trie/node.rs | 249   | +6   |
+-----------------------------------+-------+------+
| ethrex/crates/common/trie/trie.rs | 908   | +7   |
+-----------------------------------+-------+------+

[Oppen]

This should have an indication in its name that it doesn't check the validity of the hash, and the warning comment should be a SAFETY one, so it's easier to grep for.

Suggested change

	/// # Warning
	/// will lead to errors if setting the wrong hash, use only
	/// when the hash was correctly precalculated
	pub fn with_hash(self, hash: NodeHash) -> Self {
	/// # SAFETY: caller must ensure the hash is correct for the node.
	/// Otherwise, the `Trie` will silently produce incorrect results and may
	/// fail to query other nodes from the `TrieDB`.
	pub fn with_hash_unchecked(self, hash: NodeHash) -> Self {

[ilitteri]

It is safe to use it here since we passed the hash.is_valid() check, right?

[xqft]

hash.is_valid() only checks that the hash is not empty, there isn't a way to check that a hash corresponds to a preimage without hashing again