Avoid storing zero sized objects on the stack.

[ilyalesokhin-starkware]

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[orizi]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @ilyalesokhin-starkware)

---

crates/cairo-lang-sierra-generator/src/store_variables/state.rs line 50 at r1 (raw file):

    ZeroSizedVar,
    /// The variable was consumed and can no longer be used.
    /// This state is used because there is no efficent way of removing variables

Suggestion:

pub enum VarState {
    /// The variable is a temporary variable with the given type.
    TempVar { ty: sierra::ids::ConcreteTypeId },
    /// The variable is deferred with the given DeferredVariableInfo.
    Deferred { info: DeferredVariableInfo },
    /// The variable is a local variable.
    LocalVar,
    /// The variable is of size zero.
    ZeroSizedVar,
    /// The variable was consumed and can no longer be used.
    /// This state is used because there is no efficent way of removing variables

[ilyalesokhin-starkware]

Reviewable status: 0 of 62 files reviewed, 1 unresolved discussion (waiting on @orizi)

---

crates/cairo-lang-sierra-generator/src/store_variables/state.rs line 50 at r1 (raw file):

    ZeroSizedVar,
    /// The variable was consumed and can no longer be used.
    /// This state is used because there is no efficent way of removing variables

Done.

[orizi]

Reviewed 33 of 62 files at r2, all commit messages.
Reviewable status: 33 of 62 files reviewed, 1 unresolved discussion (waiting on @ilyalesokhin-starkware)

---

crates/cairo-lang-sierra/src/extensions/lib_func.rs line 387 at r3 (raw file):

    SimpleDerefs,
    // The output is a of size 0.
    ZeroSized,

Suggestion:

    SameAsParam { param_idx: usize },
    /// The output value is a part of one of the parameters.
    /// For example, it may be the first element of a struct.
    ///
    /// Information, such as whether the parameter was a temporary or local variable, will be
    /// copied to the output variable.
    PartialParam { param_idx: usize },
    /// The output was allocated as a temporary variable and it is at the top of the stack
    /// (contiguously).
    NewTempVar {
    Deferred(DeferredOutputKind),
    /// All the output cells are of the form `[ap/fp + const]`. For example, `([ap + 1], [fp])`.
    SimpleDerefs,
    /// The output is a of size 0.
    ZeroSized,

[orizi]

Reviewed 27 of 62 files at r2, 2 of 2 files at r3.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @ilyalesokhin-starkware)

[ilyalesokhin-starkware]

Reviewable status: 60 of 62 files reviewed, 1 unresolved discussion (waiting on @orizi)

---

crates/cairo-lang-sierra/src/extensions/lib_func.rs line 387 at r3 (raw file):

    SimpleDerefs,
    // The output is a of size 0.
    ZeroSized,

Done.

[orizi]

Reviewed 2 of 2 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ilyalesokhin-starkware)