Struct ControlFlowGraph 

pub struct ControlFlowGraph {
    pub blocks: HashMap<String, BasicBlock>,
    pub edges: HashMap<String, Vec<String>>,
    pub entry_block: String,
    pub exit_blocks: Vec<String>,
}

Control Flow Graph extracted from MIR basic blocks

Fields

blocks: HashMap<String, BasicBlock>

Map from block ID to BasicBlock

edges: HashMap<String, Vec<String>>

Map from block ID to successor block IDs

entry_block: String

Entry block (usually “bb0”)

exit_blocks: Vec<String>

Exit blocks (blocks with Return terminator)

Implementations

impl ControlFlowGraph

pub fn from_mir_function(function: &MirFunction) -> Self

Extract CFG from a MIR function’s body

pub fn block_count(&self) -> usize

Get the number of basic blocks in the CFG

pub fn branch_count(&self) -> usize

Count branch points in the CFG (blocks with multiple successors)

pub fn is_too_complex_for_path_enumeration(&self) -> bool

Check if this CFG is too complex for full path enumeration. Returns true if enumeration should be skipped to prevent memory explosion.

The heuristic is based on empirical observation:

• influxdb3_id: 78 blocks, 20 branches → works fine (~100 MB)
• influxdb3 serve: 2442 blocks, 381 branches → 58 GB explosion

A CFG with B branches can have up to 2^B paths. With MAX_DEPTH=50, we limit path length, but the DFS exploration tree still grows exponentially.

Safe thresholds (empirically derived):

• MAX_BLOCKS: 500 (well above typical functions, catches mega-closures)
• MAX_BRANCHES: 100 (limits exponential exploration)

pub fn get_all_paths(&self) -> (Vec<Vec<String>>, bool)

Enumerate all paths from entry to exit blocks Returns paths as sequences of block IDs

For extremely complex CFGs (large async closures, state machines), returns an empty vec to prevent memory explosion.

Returns (paths, was_skipped_due_to_complexity)

pub fn get_block(&self, block_id: &str) -> Option<&BasicBlock>

Get the basic block for a given ID

pub fn has_branching(&self) -> bool

Check if the CFG has any branching (multiple paths)

Trait Implementations

impl Clone for ControlFlowGraph

fn clone(&self) -> ControlFlowGraph

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ControlFlowGraph

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

Formats the value using the given formatter.