feat!: Support contracts with no constructor

[spalladino]

Changes:

• Breaking: constructor is no longer an enshrined function name, it's now required to flag the constructor with aztec(initializer).
• Remove need for a function named constructor in noir aztec-macros and yarn-packages
• Add isInitializer flag to contract artifact
• Default the initializer to a function that has the aztec(initializer) attribute, if there's more than one, pick one at random, preferring private ones
• When there's no initializer, the initializationHash of a contract instance is set to zero
• Remove empty constructor functions from our contracts, and flag public constructors as initializer where missing

cc @AztecProtocol/devrel

Benchmark results

Metrics with a significant change:

• tx_pxe_processing_time_ms (0): 3,258 (-18%)

Detailed results

All benchmarks are run on txs on the Benchmarking contract on the repository. Each tx consists of a batch call to create_note and increment_balance, which guarantees that each tx has a private call, a nested private call, a public call, and a nested public call, as well as an emitted private note, an unencrypted log, and public storage read and write.

This benchmark source data is available in JSON format on S3 here.

Values are compared against data from master at commit 19eb7f9b and shown if the difference exceeds 1%.

L2 block published to L1

Each column represents the number of txs on an L2 block published to L1.

Metric	8 txs	32 txs	64 txs
l1_rollup_calldata_size_in_bytes	5,668	18,820	36,356
l1_rollup_calldata_gas	66,232	238,996	469,616
l1_rollup_execution_gas	666,913	953,906	1,336,973
l2_block_processing_time_in_ms	1,279 (-12%)	4,837 (+3%)	8,963 (+3%)
note_successful_decrypting_time_in_ms	138	473 (-12%)	930 (-6%)
note_trial_decrypting_time_in_ms	41.6	89.2 (+71%)	60.4 (-51%)
l2_block_building_time_in_ms	18,457	69,648 (+1%)	137,531 (+2%)
l2_block_rollup_simulation_time_in_ms	8,273	29,110 (+1%)	56,669 (+2%)
l2_block_public_tx_process_time_in_ms	10,163	40,478	80,763 (+2%)

L2 chain processing

Each column represents the number of blocks on the L2 chain where each block has 16 txs.

Metric	5 blocks	10 blocks
node_history_sync_time_in_ms	14,499 (+3%)	27,866 (+3%)
note_history_successful_decrypting_time_in_ms	1,189 (-13%)	2,496 (+2%)
note_history_trial_decrypting_time_in_ms	60.6 (+9%)	155 (+20%)
node_database_size_in_bytes	19,079,248	35,639,376
pxe_database_size_in_bytes	29,859	59,414

Circuits stats

Stats on running time and I/O sizes collected for every circuit run across all benchmarks.

Circuit	circuit_simulation_time_in_ms	circuit_input_size_in_bytes	circuit_output_size_in_bytes
private-kernel-init	284 (+1%)	44,370	27,700
private-kernel-ordering	218 (+1%)	52,324	14,326
base-parity	1,809 (-1%)	128	311
base-rollup	724	177,083	925
root-parity	1,680 (+8%)	1,244	311
root-rollup	68.9	4,487	789
private-kernel-inner	640 (+1%)	73,229	27,700
public-kernel-app-logic	453 (+2%)	35,262	28,215
public-kernel-tail	178 (+2%)	40,926	28,215
merge-rollup	8.25 (+1%)	2,696	925

Tree insertion stats

The duration to insert a fixed batch of leaves into each tree type.

Metric	1 leaves	16 leaves	64 leaves	128 leaves	512 leaves	1024 leaves	2048 leaves	4096 leaves	32 leaves
batch_insert_into_append_only_tree_16_depth_ms	9.99	16.0	N/A	N/A	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_count	16.8	31.6	N/A	N/A	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_16_depth_hash_ms	0.583	0.494	N/A	N/A	N/A	N/A	N/A	N/A	N/A
batch_insert_into_append_only_tree_32_depth_ms	N/A	N/A	46.1 (+2%)	71.7 (+1%)	231	444 (+1%)	869 (+1%)	1,721 (+4%)	N/A
batch_insert_into_append_only_tree_32_depth_hash_count	N/A	N/A	96.0	159	543	1,055	2,079	4,127	N/A
batch_insert_into_append_only_tree_32_depth_hash_ms	N/A	N/A	0.474 (+2%)	0.443 (+1%)	0.422 (+1%)	0.416 (+1%)	0.413 (+1%)	0.412 (+4%)	N/A
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	54.6 (+3%)	106 (+1%)	338 (-1%)	669 (+2%)	1,301	2,594 (+3%)	N/A
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	104	207	691	1,363	2,707	5,395	N/A
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.488 (+3%)	0.478 (+1%)	0.459 (-1%)	0.462 (+2%)	0.452 (+1%)	0.452 (+3%)	N/A
batch_insert_into_indexed_tree_40_depth_ms	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	61.1 (+1%)
batch_insert_into_indexed_tree_40_depth_hash_count	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	109
batch_insert_into_indexed_tree_40_depth_hash_ms	N/A	N/A	N/A	N/A	N/A	N/A	N/A	N/A	0.536 (+1%)

Miscellaneous

Transaction sizes based on how many contract classes are registered in the tx.

Metric	0 registered classes
tx_size_in_bytes	22,014

Transaction processing duration by data writes.

Metric	0 new note hashes	1 new note hashes
tx_pxe_processing_time_ms	⚠️ 3,258 (-18%)	1,746 (+1%)

Metric	0 public data writes	1 public data writes
tx_sequencer_processing_time_ms	12.9 (+1%)	1,264 (+1%)

Can you add a note to the Migration Notes page (docs/docs/misc/migration_notes.md) about the breaking change?

@critesjosh done!

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