performance(sierra-to-casm): Using builder with capacity for instructions and relocations.

[orizi]

Summary

Added a with_capacity constructor to CasmBuilder to pre-allocate memory for instructions and relocations, and updated all invocation implementations to use this constructor with appropriate capacity estimates. This optimization reduces memory allocations during the Sierra to CASM compilation process.

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Type of change

Please check one:

• Bug fix (fixes incorrect behavior)
• New feature
• Performance improvement
• Documentation change with concrete technical impact
• Style, wording, formatting, or typo-only change

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Why is this change needed?

The CasmBuilder was previously using Default::default() for all vector allocations, which resulted in many small allocations and reallocations as instructions were added. By pre-allocating vectors with appropriate capacities based on the expected number of instructions and relocations for each invocation type, we can reduce memory allocations and improve compilation performance.

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What was the behavior or documentation before?

Previously, all invocations created a CasmBuilder using Default::default(), which initialized empty vectors for instructions and relocations. These vectors would need to reallocate memory as elements were added, causing performance overhead.

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What is the behavior or documentation after?

Now, CasmBuilder has a new with_capacity constructor that pre-allocates memory for instructions and relocations. All invocation implementations have been updated to use this constructor with appropriate capacity estimates based on their expected usage patterns. The Default implementation now uses with_capacity(1, 0) as a minimal allocation.

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Additional context

This change is purely a performance optimization that doesn't affect functionality. It reduces memory allocations during the Sierra to CASM compilation process, which should improve compilation speed, especially for larger programs.

[orizi]

• performance(sierra-to-casm): Using builder with capacity for instructions and relocations. #9490 👈 (View in Graphite)
• performance(casm): Made casm builder build-alg linear. #9489
• main

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[reviewable-StarkWare]

This change is 

[eytan-starkware]

@eytan-starkware reviewed 1 file and all commit messages, and made 4 comments.
Reviewable status: 1 of 33 files reviewed, 4 unresolved discussions (waiting on @orizi and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 70 at r1 (raw file):

    let [start_ptr] = builder.try_get_single_cells()?;
    let full_struct_size = builder.program_info.type_sizes[ty];
    let mut casm_builder = CasmBuilder::with_capacity(0, 0);

casm_build_extend will lead to a larger capacity. 3?

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 122 at r1 (raw file):

    let [expr_arr, elem] = builder.try_get_refs()?;
    let [arr_start, arr_end] = expr_arr.try_unpack()?;
    let mut casm_builder = CasmBuilder::with_capacity(elem.cells.len(), 0);

Isnt deref and ++ two seperate instructions?

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 182 at r1 (raw file):

    let element_size = builder.program_info.type_sizes[elem_ty];

    let mut casm_builder = CasmBuilder::with_capacity(3, 2);

I htink jumps are also part of instructions in the builder, so 5,2?

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crates/cairo-lang-sierra-to-casm/src/invocations/bitwise.rs line 24 at r1 (raw file):

    let [bitwise, x, y] = builder.try_get_single_cells()?;

    let mut casm_builder = CasmBuilder::with_capacity(2, 0);

5, 0? Do asserts create a jump?

[orizi]

@orizi made 4 comments.
Reviewable status: 1 of 33 files reviewed, 4 unresolved discussions (waiting on @eytan-starkware and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 70 at r1 (raw file):

Previously, eytan-starkware wrote…

casm_build_extend will lead to a larger capacity. 3?

no instructions are generated.
instruction count == number of asserts and jumps (tempvar with assignment is an assert as well)
relocation count == number of jumps.

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 122 at r1 (raw file):

Previously, eytan-starkware wrote…

Isnt deref and ++ two seperate instructions?

ditto.

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 182 at r1 (raw file):

Previously, eytan-starkware wrote…

I htink jumps are also part of instructions in the builder, so 5,2?

ditto.

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crates/cairo-lang-sierra-to-casm/src/invocations/bitwise.rs line 24 at r1 (raw file):

Previously, eytan-starkware wrote…

5, 0? Do asserts create a jump?

only the asserts.

[eytan-starkware]

@eytan-starkware reviewed 2 files and all commit messages, made 5 comments, and resolved 4 discussions.
Reviewable status: 2 of 33 files reviewed, 5 unresolved discussions (waiting on @orizi and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 218 at r2 (raw file):

    let index = expr_index.try_unpack_single()?;
    let element_size = builder.program_info.type_sizes[elem_ty];
    let mut casm_builder = CasmBuilder::with_capacity(9, 2);

10, 2 (I suspect it didnt count maybe_tempvar)

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 287 at r2 (raw file):

    let element_size = builder.program_info.type_sizes[elem_ty];

    let mut casm_builder = CasmBuilder::with_capacity(11, 2);

ditto?

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 354 at r2 (raw file):

    let [arr_start, arr_end] = builder.try_get_refs::<1>()?[0].try_unpack()?;
    let element_size = builder.program_info.type_sizes[elem_ty];
    let mut casm_builder = CasmBuilder::with_capacity(0, 0);

1, 0 (else case)

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 388 at r2 (raw file):

    let [arr_start, arr_end] = expr_arr.try_unpack()?;
    let popped_size = builder.program_info.type_sizes[&libfunc.popped_ty];
    let mut casm_builder = CasmBuilder::with_capacity(8, 1);

6 + 4 or 6 + 3?

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 438 at r2 (raw file):

    let [arr_start, arr_end] = expr_arr.try_unpack()?;
    let popped_size = builder.program_info.type_sizes[&libfunc.popped_ty];
    let mut casm_builder = CasmBuilder::with_capacity(8, 1);

ditto

[eytan-starkware]

I think it would just be easier to always give a capacity of 16 or 32, as it is not a lot of space, and allocation won't take longer.

@eytan-starkware made 1 comment.
Reviewable status: 2 of 33 files reviewed, 5 unresolved discussions (waiting on @orizi and @TomerStarkware).

[orizi]

even if marginal - probably better.

@orizi made 6 comments.
Reviewable status: 1 of 33 files reviewed, 5 unresolved discussions (waiting on @eytan-starkware and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 218 at r2 (raw file):

Previously, eytan-starkware wrote…

10, 2 (I suspect it didnt count maybe_tempvar)

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 287 at r2 (raw file):

Previously, eytan-starkware wrote…

ditto?

nope - recounted - 11.
(tempvar is_in_range; - not an instruction, just an allocation)

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 354 at r2 (raw file):

Previously, eytan-starkware wrote…

1, 0 (else case)

i think that case would allocate an array, so cheaper all and all.

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 388 at r2 (raw file):

Previously, eytan-starkware wrote…

6 + 4 or 6 + 3?

3+5

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crates/cairo-lang-sierra-to-casm/src/invocations/array.rs line 438 at r2 (raw file):

Previously, eytan-starkware wrote…

ditto

3 + 5

[eytan-starkware]

@eytan-starkware reviewed 10 files, made 5 comments, and resolved 5 discussions.
Reviewable status: 11 of 33 files reviewed, 5 unresolved discussions (waiting on @orizi and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/felt252_dict.rs line 731 at r3 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [dict_ptr, key] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(8, 2);

1, 0?

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crates/cairo-lang-sierra-to-casm/src/invocations/felt252_dict.rs line 755 at r3 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [dict_entry, new_value] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(8, 2);

1, 0?

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crates/cairo-lang-sierra-to-casm/src/invocations/felt252.rs line 45 at r3 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [a, b] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(0, 0);

1, 0

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crates/cairo-lang-sierra-to-casm/src/invocations/blake.rs line 38 at r3 (raw file):

        hint AllocConstantSize { size: state_size } into { dst: output };
    };
    casm_builder.blake2s_compress(state, byte_count, message, finalize);

blake adds an instruction

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crates/cairo-lang-sierra-to-casm/src/invocations/debug.rs line 23 at r3 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [arr_start, arr_end] = builder.try_get_refs::<1>()?[0].try_unpack()?;
    let mut casm_builder = CasmBuilder::with_capacity(1, 0);

0, 0 ?

[orizi]

@orizi made 5 comments.
Reviewable status: 11 of 33 files reviewed, 5 unresolved discussions (waiting on @eytan-starkware and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/blake.rs line 38 at r3 (raw file):

Previously, eytan-starkware wrote…

blake adds an instruction

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/debug.rs line 23 at r3 (raw file):

Previously, eytan-starkware wrote…

0, 0 ?

ap += 0 is an instruction.

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crates/cairo-lang-sierra-to-casm/src/invocations/felt252.rs line 45 at r3 (raw file):

Previously, eytan-starkware wrote…

1, 0

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/felt252_dict.rs line 731 at r3 (raw file):

Previously, eytan-starkware wrote…

1, 0?

Done

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crates/cairo-lang-sierra-to-casm/src/invocations/felt252_dict.rs line 755 at r3 (raw file):

Previously, eytan-starkware wrote…

1, 0?

Done.

[eytan-starkware]

@eytan-starkware reviewed 24 files and all commit messages, made 8 comments, and resolved 5 discussions.
Reviewable status: 31 of 33 files reviewed, 8 unresolved discussions (waiting on @orizi and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/starknet/storage.rs line 16 at r4 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [base, offset] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(8, 2);

0, 0?

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned.rs line 77 at r4 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [range_check, value] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(16, 4);

no jumps?

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crates/cairo-lang-sierra-to-casm/src/invocations/starknet/mod.rs line 113 at r4 (raw file):

    let [gas_builtin] = builder.refs[0].expression.try_unpack()?;
    let [system] = builder.refs[1].expression.try_unpack()?;
    let mut casm_builder = CasmBuilder::with_capacity(32, 8);

Depends on input count

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crates/cairo-lang-sierra-to-casm/src/invocations/gas.rs line 121 at r4 (raw file):

        ));
    }
    let mut casm_builder = CasmBuilder::with_capacity(8, 2);

Seems to be wrong due to loop in add_get_total_requested_count_code

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crates/cairo-lang-sierra-to-casm/src/invocations/gas.rs line 148 at r4 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [gas_counter] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(16, 4);

Also

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned128.rs line 93 at r4 (raw file):

) -> Result<CompiledInvocation, InvocationError> {
    let [a, b] = builder.try_get_single_cells()?;
    let mut casm_builder = CasmBuilder::with_capacity(8, 2);

No jumps?

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned128.rs line 122 at r4 (raw file):

    let [a, b, res_high, res_low] = guarantee.try_unpack()?;

    let mut casm_builder = CasmBuilder::with_capacity(32, 8);

Also? Can a hint cause a jump?

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned512.rs line 32 at r4 (raw file):

    let mut casm_builder = CasmBuilder::with_capacity(64, 16);
    add_input_variables! {casm_builder,

How is this only 64 and u256 is like 120

[orizi]

@orizi made 8 comments.
Reviewable status: 13 of 33 files reviewed, 8 unresolved discussions (waiting on @eytan-starkware and @TomerStarkware).

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crates/cairo-lang-sierra-to-casm/src/invocations/gas.rs line 121 at r4 (raw file):

Previously, eytan-starkware wrote…

Seems to be wrong due to loop in add_get_total_requested_count_code

decided to go with 16 that would cover almost all cases.

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crates/cairo-lang-sierra-to-casm/src/invocations/gas.rs line 148 at r4 (raw file):

Previously, eytan-starkware wrote…

Also

decided to go with 16 that would cover almost all cases.

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned.rs line 77 at r4 (raw file):

Previously, eytan-starkware wrote…

no jumps?

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned128.rs line 93 at r4 (raw file):

Previously, eytan-starkware wrote…

No jumps?

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned128.rs line 122 at r4 (raw file):

Previously, eytan-starkware wrote…

Also? Can a hint cause a jump?

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/int/unsigned512.rs line 32 at r4 (raw file):

Previously, eytan-starkware wrote…

How is this only 64 and u256 is like 120

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/starknet/mod.rs line 113 at r4 (raw file):

Previously, eytan-starkware wrote…

Depends on input count

Done.

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crates/cairo-lang-sierra-to-casm/src/invocations/starknet/storage.rs line 16 at r4 (raw file):

Previously, eytan-starkware wrote…

0, 0?

Done.

[eytan-starkware]

@eytan-starkware reviewed 20 files and all commit messages, made 1 comment, and resolved 8 discussions.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @TomerStarkware).