feat!: contract_abi-exports

[Thunkar]

Goal

This PR aims to expose arbitrary types and values resulting from contract compilation in the resulting JSON artifact, in a way that is not tied to aztec-specific features or even smart contracts at all.

Problem

Up until now, Noir compiled crates that used the contract keyword with a specific flow, which also added additional structs and metadata to the output such as whatever structs were marked with the #[event] attribute. This coupled Noir to smart contract specific constructs, which were propagated through the compiler (from the parser to the actual compilation output). For #5079 and several other tasks that aim to reduce the mental load and improve the general devex of our users, we need to expose several other structs that are even more specific to aztec, which would only compromise the generality of the compiler further.

Proposed solution

The introduction of a new attribute #[abi(tag)] that can be applied to both structs and global top-level statements, and export types (with the current ABIType format) and values (with the new ABIValue format) in a way that can be interpreted by components further downstream (for example, our typescript codegen). This way, the noir compiler doesn't know (or care) about whatever gets included in the artifact.

The events contract artifact key gets replaced by:

outputs: {
    structs: Record<string, ABIType[]>;
    globals: Record<string, ABIValue[]>;
};

What this approach allows

• Removing the smart contract specific attribute #[event], replacing it by a more general #[abi(events)].
• Substantial devex improvements, such as exposing storage layout, note ids:
  
  ...or even private function return values prior to macro processing for decoding .view calls feat(Simulate): Allow calling view on constrained functions #2665

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Benchmark results

Metrics with a significant change:

• circuit_simulation_time_in_ms (root-parity): 1,319 (+16%)
• circuit_simulation_time_in_ms (private-kernel-inner): 259 (+19%)
• circuit_input_size_in_bytes (base-rollup): 140,093 (+20%)
• circuit_output_size_in_bytes (private-kernel-ordering): 27,146 (-31%)
• circuit_output_size_in_bytes (public-kernel-tail): 20,496 (+54%)
• tx_size_in_bytes (0): 28,015 (-31%)
• note_trial_decrypting_time_in_ms (8): 59.6 (+533%)

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 d827705f 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	676	676	676
l1_rollup_calldata_gas	6,412	6,418	6,412
l1_rollup_execution_gas	585,745	585,751	585,745
l2_block_processing_time_in_ms	1,323 (+1%)	4,887 (+1%)	9,429
note_successful_decrypting_time_in_ms	206 (-1%)	558 (-9%)	953 (+1%)
note_trial_decrypting_time_in_ms	⚠️ 59.6 (+533%)	22.2 (+18%)	78.2 (+28%)
l2_block_building_time_in_ms	12,954 (+8%)	47,433 (+10%)	94,562 (+11%)
l2_block_rollup_simulation_time_in_ms	7,548 (+6%)	26,230 (+8%)	51,762 (+10%)
l2_block_public_tx_process_time_in_ms	5,373 (+12%)	21,115 (+14%)	42,633 (+14%)

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	13,895 (-9%)	26,342 (-4%)
note_history_successful_decrypting_time_in_ms	1,259 (+1%)	2,423 (+3%)
note_history_trial_decrypting_time_in_ms	91.2 (+24%)	126 (+50%)
node_database_size_in_bytes	18,634,832	35,035,216
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	206 (+14%)	44,377	27,161 (+4%)
private-kernel-ordering	183 (+13%)	51,827 (+2%)	⚠️ 27,146 (-31%)
base-parity	4,243	128	311
root-parity	⚠️ 1,319 (+16%)	1,244	311
base-rollup	16,147 (+12%)	⚠️ 140,093 (+20%)	861
root-rollup	48.9 (-4%)	4,359	725
private-kernel-inner	⚠️ 259 (+19%)	72,734 (+1%)	27,154 (+4%)
public-kernel-app-logic	121 (+1%)	41,543 (-13%)	34,508 (-15%)
public-kernel-tail	165 (+1%)	47,355 (-11%)	⚠️ 20,496 (+54%)
merge-rollup	9.30 (-10%)	2,568	861
public-kernel-teardown	113 (-3%)	47,695	40,661
public-kernel-setup	112 (-3%)	47,695	40,661

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	9.96 (-1%)	15.9 (-1%)	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	0.580	0.490 (-1%)	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	46.4 (+1%)	72.1	233	442	878	1,732 (+1%)	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	0.476 (+1%)	0.445	0.424	0.413 (+1%)	0.417	0.415	N/A
batch_insert_into_indexed_tree_20_depth_ms	N/A	N/A	53.6 (-1%)	107	343 (+1%)	658 (+1%)	1,318 (+1%)	2,618 (+1%)	N/A
batch_insert_into_indexed_tree_20_depth_hash_count	N/A	N/A	104 (-1%)	207	691	1,363	2,707	5,395	N/A
batch_insert_into_indexed_tree_20_depth_hash_ms	N/A	N/A	0.475	0.482	0.464	0.454 (+1%)	0.456 (+1%)	0.456 (+1%)	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	61.0
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	0.533

Miscellaneous

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

Metric	0 registered classes	1 registered classes
tx_size_in_bytes	⚠️ 28,015 (-31%)	499,066

Transaction size based on fee payment method

Metric	native fee payment method	fpc_public fee payment method	fpc_private fee payment method
tx_with_fee_size_in_bytes	905	1,161	1,377

Transaction processing duration by data writes.

Metric	0 new note hashes	1 new note hashes	2 new note hashes
tx_pxe_processing_time_ms	1,848 (+7%)	1,234 (+13%)	5,212 (-4%)

Metric	0 public data writes	1 public data writes	2 public data writes	3 public data writes	4 public data writes	5 public data writes	8 public data writes
tx_sequencer_processing_time_ms	16.4	648 (+12%)	422 (-3%)	1,030 (-4%)	508 (-4%)	1,683 (-4%)	564 (-4%)

[TomAFrench]

Yep, I'm saying that if we decide to allow generic Noir programs to export types/values in future (something relatively likely) then we're probably going to make changes to this feature which may break how it's currently being used.