Enum Terminator 

pub enum Terminator {
    Jump {
        target: BlockId,
        range: SourceRange,
    },
    Branch {
        cond: Expr,
        then_blk: BlockId,
        else_blk: BlockId,
    },
    IndirectJump {
        target: Expr,
        blocks: Vec<BlockId>,
        range: SourceRange,
    },
    Switch {
        value: Expr,
        cases: Vec<(CaseRange, BlockId)>,
        default: BlockId,
        range: SourceRange,
    },
    Return {
        value: Option<Expr>,
        range: SourceRange,
    },
    Unreachable,
}

How a BasicBlock ends.

Variants

Jump

Control moves to another block.

Fields

target: BlockId

The block entered.

range: SourceRange

The construct the edge came from.

Branch

Control moves to one of two blocks depending on a condition.

Fields

cond: Expr

The controlling expression.

then_blk: BlockId

Entered when cond is non-zero.

else_blk: BlockId

Entered otherwise.

IndirectJump

GNU’s computed goto *e: control moves to the block whose number the pointer holds.

The blocks it can enter are the ones of every label whose address the function took, which is what keeps them reachable, numbered and unmerged; see Cfg::labels. The generated code stores the number in the state variable and goes round the dispatch again, so a value that is not one of them lands on the unreachable!() arm — which is the undefined behaviour C already had.

Fields

target: Expr

The pointer jumped through.

blocks: Vec<BlockId>

Every block a label’s address could name.

range: SourceRange

Where the statement was written.

Switch

A switch dispatch.

Fields

value: Expr

The controlling expression, after the integer promotions.

cases: Vec<(CaseRange, BlockId)>

The case labels and the blocks they enter, in source order.

default: BlockId

Where default: goes — past the statement when there is none.

range: SourceRange

Where the statement was written.

Return

The function returns.

Fields

value: Option<Expr>

The returned value.

range: SourceRange

Where the statement was written.

Unreachable

Control never gets here.

Only reachable through a bug in this module, and emitted as unreachable!() so that such a bug is loud rather than silent.

Trait Implementations

impl Clone for Terminator

fn clone(&self) -> Self

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.