refactor: store array data pointer inline, drop ArrayMetadata.

[TomerStarkware]

Refactor: store array data pointer inline, drop ArrayMetadata

Closes #NA

Removes the ArrayMetadata { max_len, data_ptr } indirection. The array struct still has shape {ptr, start, end, capacity}, but ptr now points directly to the element buffer instead of to a heap-allocated metadata struct. max_len was only ever written, never read.

Net effect per array op: one fewer arena allocation and one fewer load.

Introduces Breaking Changes?

Yes.

ArrayAbi.ptr changes from *mut *mut T to *mut T. Any external consumer reading ArrayAbi (notably starknet-replay and the sequencer fork) must follow.

• Created PR in sequencer
• Created PR in starknet-replay
• Updated the starknet-blocks.yml workflow to use these PRs.

These PRs should be merged after this one right away, in that order.

Checklist

• Linked to Github Issue.
• Unit tests added. (existing array/snapshot/dict-array tests cover the new layout)
• Integration tests added.
• This change requires new documentation.
  • Documentation has been added/updated. (layout table in src/types/array.rs)

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This change is 

[github-actions]

Benchmarking results

Benchmark for program dict_insert

Open benchmarks

Command	Mean [s]	Min [s]	Max [s]	Relative
Cairo-vm (Rust, Cairo 1)	11.678 ± 0.055	11.562	11.730	6.29 ± 0.06
cairo-native (embedded AOT)	1.856 ± 0.017	1.838	1.885	1.00
cairo-native (embedded JIT using LLVM's ORC Engine)	1.876 ± 0.008	1.867	1.891	1.01 ± 0.01

Benchmark for program dict_snapshot

Open benchmarks

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Cairo-vm (Rust, Cairo 1)	539.1 ± 3.2	535.0	546.0	1.00
cairo-native (embedded AOT)	1678.8 ± 10.7	1666.0	1694.9	3.11 ± 0.03
cairo-native (embedded JIT using LLVM's ORC Engine)	1703.3 ± 9.5	1691.1	1724.7	3.16 ± 0.03

Benchmark for program factorial_2M

Open benchmarks

Command	Mean [s]	Min [s]	Max [s]	Relative
Cairo-vm (Rust, Cairo 1)	5.115 ± 0.016	5.088	5.144	2.39 ± 0.02
cairo-native (embedded AOT)	2.141 ± 0.017	2.117	2.170	1.00
cairo-native (embedded JIT using LLVM's ORC Engine)	2.154 ± 0.015	2.130	2.183	1.01 ± 0.01

Benchmark for program fib_2M

Open benchmarks

Command	Mean [s]	Min [s]	Max [s]	Relative
Cairo-vm (Rust, Cairo 1)	5.018 ± 0.023	4.973	5.049	2.97 ± 0.03
cairo-native (embedded AOT)	1.691 ± 0.017	1.666	1.718	1.00
cairo-native (embedded JIT using LLVM's ORC Engine)	1.709 ± 0.013	1.690	1.734	1.01 ± 0.01

Benchmark for program linear_search

Open benchmarks

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Cairo-vm (Rust, Cairo 1)	581.9 ± 7.5	571.0	591.6	1.00
cairo-native (embedded AOT)	1697.8 ± 16.1	1671.1	1715.5	2.92 ± 0.05
cairo-native (embedded JIT using LLVM's ORC Engine)	1733.2 ± 12.0	1719.1	1749.5	2.98 ± 0.04

Benchmark for program logistic_map

Open benchmarks

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
Cairo-vm (Rust, Cairo 1)	491.9 ± 3.5	486.3	498.5	1.00
cairo-native (embedded AOT)	1829.8 ± 11.5	1809.6	1848.0	3.72 ± 0.04
cairo-native (embedded JIT using LLVM's ORC Engine)	1948.9 ± 6.6	1940.8	1961.6	3.96 ± 0.03

[github-actions]

Benchmark results Main vs HEAD.

Base

Command	Mean [s]	Min [s]	Max [s]	Relative
base dict_insert.cairo (JIT)	1.951 ± 0.030	1.895	2.003	1.00
base dict_insert.cairo (AOT)	1.969 ± 0.019	1.935	1.994	1.01 ± 0.02

Head

Command	Mean [s]	Min [s]	Max [s]	Relative
head dict_insert.cairo (JIT)	1.975 ± 0.085	1.906	2.115	1.05 ± 0.05
head dict_insert.cairo (AOT)	1.881 ± 0.018	1.857	1.911	1.00

Base

Command	Mean [s]	Min [s]	Max [s]	Relative
base dict_snapshot.cairo (JIT)	1.764 ± 0.036	1.712	1.825	1.00 ± 0.03
base dict_snapshot.cairo (AOT)	1.763 ± 0.028	1.728	1.803	1.00

Head

Command	Mean [s]	Min [s]	Max [s]	Relative
head dict_snapshot.cairo (JIT)	1.711 ± 0.014	1.688	1.726	1.01 ± 0.01
head dict_snapshot.cairo (AOT)	1.686 ± 0.014	1.666	1.712	1.00

Base

Command	Mean [s]	Min [s]	Max [s]	Relative
base factorial_2M.cairo (JIT)	2.302 ± 0.057	2.207	2.426	1.00
base factorial_2M.cairo (AOT)	2.305 ± 0.041	2.256	2.380	1.00 ± 0.03

Head

Command	Mean [s]	Min [s]	Max [s]	Relative
head factorial_2M.cairo (JIT)	2.184 ± 0.014	2.160	2.201	1.00 ± 0.01
head factorial_2M.cairo (AOT)	2.173 ± 0.016	2.150	2.201	1.00

Base

Command	Mean [s]	Min [s]	Max [s]	Relative
base fib_2M.cairo (JIT)	1.858 ± 0.023	1.824	1.902	1.00 ± 0.02
base fib_2M.cairo (AOT)	1.850 ± 0.017	1.817	1.873	1.00

Head

Command	Mean [s]	Min [s]	Max [s]	Relative
head fib_2M.cairo (JIT)	1.709 ± 0.020	1.693	1.761	1.01 ± 0.01
head fib_2M.cairo (AOT)	1.685 ± 0.015	1.668	1.719	1.00

Base

Command	Mean [s]	Min [s]	Max [s]	Relative
base linear_search.cairo (JIT)	1.892 ± 0.023	1.859	1.931	1.01 ± 0.02
base linear_search.cairo (AOT)	1.869 ± 0.027	1.819	1.905	1.00

Head

Command	Mean [s]	Min [s]	Max [s]	Relative
head linear_search.cairo (JIT)	1.750 ± 0.030	1.724	1.829	1.02 ± 0.04
head linear_search.cairo (AOT)	1.722 ± 0.055	1.682	1.837	1.00

Base

Command	Mean [s]	Min [s]	Max [s]	Relative
base logistic_map.cairo (JIT)	2.149 ± 0.047	2.087	2.229	1.08 ± 0.03
base logistic_map.cairo (AOT)	1.997 ± 0.033	1.943	2.050	1.00

Head

Command	Mean [s]	Min [s]	Max [s]	Relative
head logistic_map.cairo (JIT)	1.976 ± 0.028	1.946	2.046	1.06 ± 0.02
head logistic_map.cairo (AOT)	1.859 ± 0.032	1.831	1.923	1.00

[orizi]

@orizi reviewed 7 files and all commit messages, and made 1 comment.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on TomerStarkware).