Enum Terminator 

pub enum Terminator {
    Goto {
        target: BlockId,
        args_start: u32,
        args_len: u32,
    },
    Branch {
        cond: CfgValue,
        then_block: BlockId,
        then_args_start: u32,
        then_args_len: u32,
        else_block: BlockId,
        else_args_start: u32,
        else_args_len: u32,
    },
    Switch {
        scrutinee: CfgValue,
        cases_start: u32,
        cases_len: u32,
        default: BlockId,
    },
    Return {
        value: Option<CfgValue>,
    },
    Unreachable,
    None,
}

Block terminator - how control leaves a basic block.

Terminators are the ONLY place where control flow happens in the CFG.

Block arguments are stored in the CFG’s extra array for efficiency. Use Cfg::get_goto_args(), Cfg::get_branch_then_args(), and Cfg::get_branch_else_args() to retrieve the arguments.

Variants

Goto

Unconditional jump to another block. Arguments are stored in Cfg’s extra array.

Fields

target: BlockId

args_start: u32

Start index into Cfg’s extra array

args_len: u32

Number of arguments

Branch

Conditional branch. Arguments for each branch are stored in Cfg’s extra array.

Fields

cond: CfgValue

then_block: BlockId

then_args_start: u32

Start index into Cfg’s extra array for then branch args

then_args_len: u32

Number of arguments for then branch

else_block: BlockId

else_args_start: u32

Start index into Cfg’s extra array for else branch args

else_args_len: u32

Number of arguments for else branch

Switch

Multi-way branch (switch/match). Cases are stored in Cfg’s switch_cases array.

Fields

scrutinee: CfgValue

The value to switch on

cases_start: u32

Start index into Cfg’s switch_cases array

cases_len: u32

Number of cases

default: BlockId

Default block (for wildcard pattern)

Return

Return from function (None for unit-returning functions).

Fields

value: Option<CfgValue>

Unreachable

Unreachable - control never reaches here. Used after diverging expressions.

None

Placeholder for blocks under construction. Should not exist in a valid CFG.

Trait Implementations

impl Clone for Terminator

fn clone(&self) -> Terminator

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Terminator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for Terminator