(opt): Libfunc for matching on a boxed enum for boxed variants results

[eytan-starkware]

Summary

Added support for enum_boxed_match libfunc that allows matching on boxed enums, returning boxes of the variant types. This complements the existing struct_boxed_deconstruct functionality and enables more efficient handling of boxed enum types.

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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?

When working with boxed enums, there was no direct way to match on the enum and get boxed variants without unboxing and reboxing. This implementation allows for more efficient handling of boxed enum types by providing a direct way to match on a boxed enum and get boxes of the variant types.

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What was the behavior or documentation before?

Previously, to match on a boxed enum and work with its variants as boxes, you would need to unbox the enum, match on it, and then box each variant again. This was inefficient and required more code.

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What is the behavior or documentation after?

Now, the enum_boxed_match libfunc allows directly matching on a boxed enum and getting boxes of the variant types. This is similar to how struct_boxed_deconstruct works for structs. The implementation handles different variant sizes correctly, including padding for right-aligned variants.

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Additional context

The implementation includes refactoring of the box unpacking functionality to reduce code duplication between struct and enum implementations. The BoxUnpackLibfunc trait was introduced to share common logic between struct_boxed_deconstruct and enum_boxed_match.

[reviewable-StarkWare]

This change is 

[eytan-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
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• (opt): Libfunc for matching on a boxed enum for boxed variants results #9378 👈 (View in Graphite)
• (refactor): Build jump and jump table to support prepended instructions. #9463
• Refactored boxed deconstruct signature code, creating reusable functions #9462
• (test): Adding casm run and trace to e2e tests #9482
• main

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[TomerStarkware]

@TomerStarkware reviewed 9 files and all commit messages, and made 1 comment.
Reviewable status: 9 of 10 files reviewed, all discussions resolved (waiting on @ilyalesokhin-starkware and @orizi).

[orizi]

@orizi reviewed all commit messages and made 1 comment.
Reviewable status: 9 of 10 files reviewed, 1 unresolved discussion (waiting on @eytan-starkware and @ilyalesokhin-starkware).

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crates/cairo-lang-sierra-ap-change/src/core_libfunc_ap_change.rs line 301 at r1 (raw file):

                signature, ..
            })
            | EnumConcreteLibfunc::BoxedMatch(EnumBoxedMatchConcreteLibfunc {

this sounds incorrect - as box match should include a deref before the match.

[orizi]

@orizi made 1 comment.
Reviewable status: 9 of 10 files reviewed, 2 unresolved discussions (waiting on @eytan-starkware and @ilyalesokhin-starkware).

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tests/e2e_test_data/libfuncs/enum line 527 at r1 (raw file):

//! > casm
jmp rel 7 if [fp + -3] != 0;

[fp + -3] is a pointer

Suggestion:

[ap + 0] = [[fp + -3]], ap++;
jmp rel 7 if [fp + -3] != 0;

[eytan-starkware]

@eytan-starkware made 2 comments.
Reviewable status: 5 of 10 files reviewed, 2 unresolved discussions (waiting on @ilyalesokhin-starkware, @orizi, and @TomerStarkware).

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crates/cairo-lang-sierra-ap-change/src/core_libfunc_ap_change.rs line 301 at r1 (raw file):

Previously, orizi wrote…

this sounds incorrect - as box match should include a deref before the match.

Done

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tests/e2e_test_data/libfuncs/enum line 527 at r1 (raw file):

Previously, orizi wrote…

[fp + -3] is a pointer

Done.

[orizi]

@orizi reviewed all commit messages and made 2 comments.
Reviewable status: 5 of 10 files reviewed, 4 unresolved discussions (waiting on @eytan-starkware, @ilyalesokhin-starkware, and @TomerStarkware).

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tests/e2e_test_data/libfuncs/enum line 524 at r2 (raw file):

        BoxedOption::None(_) => BoxTrait::new(0),
    }
}

and so on.

Suggestion:

fn foo(e: Box<Option>) -> BoxedOption {
    enum_boxed_match(e)
}

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tests/e2e_test_data/libfuncs/enum line 676 at r2 (raw file):

        },
    }
}

Suggestion:

fn foo(e: Box<Data>) -> BoxedData {
    enum_boxed_match(e)
}

[eytan-starkware]

@eytan-starkware made 2 comments.
Reviewable status: 5 of 10 files reviewed, 4 unresolved discussions (waiting on @ilyalesokhin-starkware, @orizi, and @TomerStarkware).

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tests/e2e_test_data/libfuncs/enum line 524 at r2 (raw file):

Previously, orizi wrote…

and so on.

Done.

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tests/e2e_test_data/libfuncs/enum line 676 at r2 (raw file):

        },
    }
}

Done.

[TomerStarkware]

@TomerStarkware partially reviewed 4 files and made 1 comment.
Reviewable status: 8 of 10 files reviewed, 4 unresolved discussions (waiting on @ilyalesokhin-starkware and @orizi).

[orizi]

@orizi reviewed all commit messages, made 1 comment, and resolved 1 discussion.
Reviewable status: 5 of 10 files reviewed, 4 unresolved discussions (waiting on @eytan-starkware, @ilyalesokhin-starkware, and @TomerStarkware).

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a discussion (no related file):
this PR now requires an actual audit - as it already touches too much existing code.

requires major simplification or splitting.

[eytan-starkware]

@eytan-starkware made 1 comment.
Reviewable status: 3 of 10 files reviewed, 4 unresolved discussions (waiting on @ilyalesokhin-starkware, @orizi, and @TomerStarkware).

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a discussion (no related file):

Previously, orizi wrote…

this PR now requires an actual audit - as it already touches too much existing code.

requires major simplification or splitting.

Now?