chore(audit): Brillig VM nits

[aakoshh]

Description

Problem*

No issue, just part of auditing Brillig.

Summary*

Small changes to make the Brillig VM variable names more consistent, add more docs, some helper structures to capture idioms. Haven't found anything that didn't look correct.

• Add docs to some of the public methods that didn't have any.
• Change the names of some of the variables which I believe harken back to times when memory used RegisterIndex instead of MemoryAddress
• Changed VM::process_opcode to return a &Status instead of Status which avoids one or two .clone() calls: set_status called .clone() to return a copy, which was then pattern matched on in process_opcodes, which also returned a .clone() at the end. We only need a clone when we are suspending processes, not when pattern matching.
• Added ArrayAddress and VectorAddress so we don't have to have .offset(1) and .offset(2) sprinkled around the codebase, explained by surrounding comments about the memory layout of arrays and vectors.
• Moved bit size check into evaluate_binary_int_op_shifts: it already did it when we returned 0 instead of error, which made it inconsistent with the surrounding code.
• Added a STACK_POINTER_ADDRESS to the memory module so Memory and ReservedRegisters in the VM can both refer to it, formalising the contract.
• Added has_unprocessed_foreign_call_result to explain foreign_call_counter (I found the error message confusing and wasn't clear whether the counter should be ahead or behind the length of responses).
• Steer opcode processing towards fail! rather than .expect, where some opcode is processed by returning Err, while another panics. .to_usize() seems to be the only one which still panics, but it's so ubiquitous I didn't touch it.
• Renamed write_values_to_memory_slice and write_slice_of_values_to_memory because they seem easy to confuse with each other.
• Added a write_heap_array and write_heap_vector counterpart to the read_heap_* functions.

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Test Suite Duration'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
test_report_zkpassport_noir-ecdsa_	3 s	2 s	1.50
test_report_zkpassport_noir_rsa_	2 s	1 s	2

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Execution Time'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
rollup-block-root-single-tx	0.003 s	0.002 s	1.50

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Compilation Time'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.20.

Benchmark suite	Current: 55d94b4	Previous: 0ec7e29	Ratio
rollup-tx-base-public	129.6 s	76.62 s	1.69

This comment was automatically generated by workflow using github-action-benchmark.

CC: @TomAFrench

[asterite]

Neat!!

[github-actions]

ACVM Benchmarks

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
purely_sequential_opcodes	270691 ns/iter (± 2124)	259405 ns/iter (± 941)	1.04
perfectly_parallel_opcodes	242450 ns/iter (± 3314)	229338 ns/iter (± 3083)	1.06
perfectly_parallel_batch_inversion_opcodes	2806501 ns/iter (± 5587)	2799647 ns/iter (± 2697)	1.00

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Test Suite Duration

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
test_report_AztecProtocol_aztec-packages_noir-projects_aztec-nr	120 s	116 s	1.03
test_report_AztecProtocol_aztec-packages_noir-projects_noir-contracts	134 s	132 s	1.02
test_report_AztecProtocol_aztec-packages_noir-projects_noir-protocol-circuits_crates_blob	279 s	335 s	0.83
test_report_AztecProtocol_aztec-packages_noir-projects_noir-protocol-circuits_crates_private-kernel-lib	229 s	228 s	1.00
test_report_AztecProtocol_aztec-packages_noir-projects_noir-protocol-circuits_crates_types	127 s	128 s	0.99
test_report_noir-lang_noir-bignum_	170 s	157 s	1.08
test_report_noir-lang_noir_bigcurve_	333 s	374 s	0.89
test_report_noir-lang_sha256_	15 s	14 s	1.07
test_report_noir-lang_sha512_	14 s	13 s	1.08
test_report_zkpassport_noir-ecdsa_	3 s	2 s	1.50
test_report_zkpassport_noir_rsa_	2 s	1 s	2

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Artifact Size

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
private-kernel-inner	714.3 KB	714.3 KB	1
private-kernel-reset	1864 KB	1864 KB	1
private-kernel-tail	546.2 KB	546.2 KB	1
rollup-block-root-first-empty-tx	179.6 KB	179.6 KB	1
rollup-block-root-single-tx	177.9 KB	177.9 KB	1
rollup-block-root	257.9 KB	257.9 KB	1
rollup-checkpoint-merge	370.6 KB	370.6 KB	1
rollup-checkpoint-root-single-block	27640.2 KB	27640.2 KB	1
rollup-checkpoint-root	27685.9 KB	27685.9 KB	1
rollup-root	411.4 KB	411.4 KB	1
rollup-tx-base-private	4909.3 KB	4909.3 KB	1
rollup-tx-base-public	4555.4 KB	4555.4 KB	1
rollup-tx-merge	186.1 KB	186.1 KB	1
semaphore-depth-10	570.9 KB	570.9 KB	1
sha512-100-bytes	506.3 KB	506.3 KB	1

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Opcode count

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
private-kernel-inner	14544 opcodes	14544 opcodes	1
private-kernel-reset	70415 opcodes	70415 opcodes	1
private-kernel-tail	11680 opcodes	11680 opcodes	1
rollup-block-root-first-empty-tx	1364 opcodes	1364 opcodes	1
rollup-block-root-single-tx	1048 opcodes	1048 opcodes	1
rollup-block-root	2409 opcodes	2409 opcodes	1
rollup-checkpoint-merge	2130 opcodes	2130 opcodes	1
rollup-checkpoint-root-single-block	962015 opcodes	962015 opcodes	1
rollup-checkpoint-root	963375 opcodes	963375 opcodes	1
rollup-root	2630 opcodes	2630 opcodes	1
rollup-tx-base-private	263908 opcodes	263908 opcodes	1
rollup-tx-base-public	245185 opcodes	245185 opcodes	1
rollup-tx-merge	1486 opcodes	1486 opcodes	1
semaphore-depth-10	5699 opcodes	5699 opcodes	1
sha512-100-bytes	13173 opcodes	13173 opcodes	1

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Compilation Time

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
private-kernel-inner	1.84 s	1.86 s	0.99
private-kernel-reset	6.856 s	6.774 s	1.01
private-kernel-tail	1.326 s	1.426 s	0.93
rollup-block-root-first-empty-tx	1.42 s	1.58 s	0.90
rollup-block-root-single-tx	1.4 s	1.38 s	1.01
rollup-block-root	1.5 s	1.45 s	1.03
rollup-checkpoint-merge	1.546 s	1.398 s	1.11
rollup-checkpoint-root-single-block	197 s	194 s	1.02
rollup-checkpoint-root	197 s	214 s	0.92
rollup-root	1.494 s	1.556 s	0.96
rollup-tx-base-private	19.52 s	17.86 s	1.09
rollup-tx-base-public	76.3 s	76.2 s	1.00
rollup-tx-merge	1.386 s	1.366 s	1.01
semaphore-depth-10	0.786 s	0.793 s	0.99
sha512-100-bytes	1.665 s	1.725 s	0.97

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Execution Time

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
private-kernel-inner	0.011 s	0.012 s	0.92
private-kernel-reset	0.146 s	0.155 s	0.94
private-kernel-tail	0.009 s	0.01 s	0.90
rollup-block-root-first-empty-tx	0.003 s	0.003 s	1
rollup-block-root-single-tx	0.003 s	0.002 s	1.50
rollup-block-root	0.004 s	0.004 s	1
rollup-checkpoint-merge	0.003 s	0.004 s	0.75
rollup-checkpoint-root-single-block	11.2 s	12.8 s	0.87
rollup-checkpoint-root	11.3 s	12.7 s	0.89
rollup-root	0.004 s	0.004 s	1
rollup-tx-base-private	0.299 s	0.302 s	0.99
rollup-tx-base-public	0.241 s	0.243 s	0.99
rollup-tx-merge	0.002 s	0.002 s	1
semaphore-depth-10	0.008 s	0.009 s	0.89
sha512-100-bytes	0.048 s	0.091 s	0.53

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Compilation Memory

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
private-kernel-inner	265.5 MB	265.5 MB	1
private-kernel-reset	493.18 MB	493.18 MB	1
private-kernel-tail	247.54 MB	247.54 MB	1
rollup-block-root-first-empty-tx	340.02 MB	340.02 MB	1
rollup-block-root-single-tx	337.42 MB	337.43 MB	1.00
rollup-block-root	340.43 MB	340.43 MB	1
rollup-checkpoint-merge	339.76 MB	339.76 MB	1
rollup-checkpoint-root-single-block	6810 MB	6810 MB	1
rollup-checkpoint-root	6810 MB	6810 MB	1
rollup-root	344.07 MB	344.07 MB	1
rollup-tx-base-private	1050 MB	1050 MB	1
rollup-tx-base-public	2890 MB	2890 MB	1
rollup-tx-merge	337.64 MB	337.64 MB	1
semaphore_depth_10	92.18 MB	92.18 MB	1
sha512_100_bytes	185.47 MB	185.53 MB	1.00

This comment was automatically generated by workflow using github-action-benchmark.

[github-actions]

Execution Memory

Details

Benchmark suite	Current: dab710f	Previous: 077dd5e	Ratio
private-kernel-inner	253.63 MB	253.63 MB	1
private-kernel-reset	287.24 MB	287.24 MB	1
private-kernel-tail	243.5 MB	243.5 MB	1
rollup-block-root	337.87 MB	337.87 MB	1
rollup-checkpoint-merge	336.67 MB	336.67 MB	1
rollup-checkpoint-root-single-block	1020 MB	1020 MB	1
rollup-checkpoint-root	1020 MB	1020 MB	1
rollup-root	337.87 MB	337.87 MB	1
rollup-tx-base-private	451.42 MB	451.42 MB	1
rollup-tx-base-public	466.49 MB	466.49 MB	1
rollup-tx-merge	336.13 MB	336.13 MB	1
semaphore_depth_10	73.7 MB	73.7 MB	1
sha512_100_bytes	71.96 MB	71.96 MB	1

This comment was automatically generated by workflow using github-action-benchmark.

[vezenovm]

rollup-checkpoint-root-single-block 11.2 s 12.8 s 0.87
rollup-checkpoint-root 11.3 s 12.7 s 0.89

Nice!