Function solve_frame_states

src/lower2/stackmaps.rs:389–437

(
    instructions: &[Instruction],
    initial_locals: &[FrameValue],
    local_hints: &[FrameValue],
    max_locals: usize,
    constant_pool: &ConstantPool,
    context: &str,
)

    initial_locals: &[FrameValue],
    local_hints: &[FrameValue],
    max_locals: u16,
    constant_pool: &ConstantPool,
    context: &str,
    exception_table: &mut [ExceptionTableEntry],
) -> jvm::Result<(usize, FrameAnalysis)> {
    if instructions.is_empty() {
        return Ok((
            0,
            FrameAnalysis {
                block_starts: Vec::new(),
                entry_states: Vec::new(),
            },
        ));
    }

    let locals = locals_loaded_before_definite_store(
        instructions,
        initial_locals,
        max_locals as usize,
        context,
        exception_table,
    )?;
    if locals.is_empty() {
        let analysis = solve_frame_states(
            instructions,
            initial_locals,
            local_hints,
            max_locals as usize,
            constant_pool,
            context,
            exception_table,
        )?;
        return Ok((0, analysis));
    }

    let mut prefix = Vec::with_capacity(locals.len() * 2);
    for (local, value) in locals {
        prefix.extend(default_local_initializer(local, &value));
    }
    let prefix_len = u16::try_from(prefix.len()).map_err(|_| jvm::Error::VerificationError {
        context: context.to_string(),
        message: "Verifier local-initialization prefix exceeds the JVM instruction limit"
            .to_string(),
    })?;
    shift_absolute_branch_targets(instructions, prefix_len, context)?;
    instructions.splice(0..0, prefix);
    shift_exception_table(exception_table, prefix_len, context)?;

    let remaining = locals_loaded_before_definite_store(
        instructions,
        initial_locals,
        max_locals as usize,