Function verify

language/move-bytecode-verifier/src/control_flow.rs:16–39

(
    current_function_opt: Option<FunctionDefinitionIndex>,
    code: &CodeUnit,
)

use std::{collections::HashSet, convert::TryInto};

pub fn verify(
    current_function_opt: Option<FunctionDefinitionIndex>,
    code: &CodeUnit,
) -> PartialVMResult<()> {
    let current_function = current_function_opt.unwrap_or(FunctionDefinitionIndex(0));
    // check fall through
    // Check to make sure that the bytecode vector ends with a branching instruction.
    match code.code.last() {
        None => return Err(PartialVMError::new(StatusCode::EMPTY_CODE_UNIT)),
        Some(last) if !last.is_unconditional_branch() => {
            return Err(PartialVMError::new(StatusCode::INVALID_FALL_THROUGH)
                .at_code_offset(current_function, (code.code.len() - 1) as CodeOffset))
        }
        Some(_) => (),
    }

    // check jumps
    let context = &ControlFlowVerifier {
        current_function,
        code: &code.code,
    };
    let labels = instruction_labels(context);
    check_jumps(context, labels)
}

#[derive(Clone, Copy)]
enum Label {