wasmtime/cranelift/tests/cfg_traversal.rs

extern crate cretonne;
extern crate cton_reader;

use self::cretonne::flowgraph::ControlFlowGraph;
use self::cretonne::dominator_tree::DominatorTree;
use self::cretonne::ir::Ebb;
use self::cton_reader::parse_functions;

fn test_reverse_postorder_traversal(function_source: &str, ebb_order: Vec<u32>) {
    let func = &parse_functions(function_source).unwrap()[0];
    let cfg = ControlFlowGraph::with_function(&func);
    let domtree = DominatorTree::with_function(&func, &cfg);

    let got = domtree
        .cfg_postorder()
        .iter()
        .rev()
        .cloned()
        .collect::<Vec<_>>();
    let want = ebb_order
        .iter()
        .map(|&n| Ebb::with_number(n).unwrap())
        .collect::<Vec<_>>();
    assert_eq!(got, want);
}

#[test]
fn simple_traversal() {
    test_reverse_postorder_traversal(
        "
        function %test(i32) native {
            ebb0(v0: i32):
               brz v0, ebb1
               jump ebb2
            ebb1:
                jump ebb3
            ebb2:
                v1 = iconst.i32 1
                v2 = iadd v1, v0
                brz v2, ebb2
                v3 = iadd v1, v2
                brz v3, ebb1
                v4 = iadd v1, v3
                brz v4, ebb4
                jump ebb5
            ebb3:
                trap user0
            ebb4:
                trap user0
            ebb5:
                trap user0
        }
    ",
        vec![0, 2, 5, 4, 1, 3],
    );
}

#[test]
fn loops_one() {
    test_reverse_postorder_traversal(
        "
        function %test(i32) native {
            ebb0(v0: i32):
                jump ebb1
            ebb1:
                brnz v0, ebb3
                jump ebb2
            ebb2:
                jump ebb3
            ebb3:
                return
        }
    ",
        vec![0, 1, 2, 3],
    );
}

#[test]
fn loops_two() {
    test_reverse_postorder_traversal(
        "
        function %test(i32) native {
            ebb0(v0: i32):
                brz v0, ebb1
                jump ebb2
            ebb1:
                jump ebb3
            ebb2:
                brz v0, ebb4
                jump ebb5
            ebb3:
                jump ebb4
            ebb4:
                brz v0, ebb3
                jump ebb5
            ebb5:
                brz v0, ebb4
                return
        }
    ",
        vec![0, 2, 1, 3, 4, 5],
    );
}

#[test]
fn loops_three() {
    test_reverse_postorder_traversal(
        "
        function %test(i32) native {
            ebb0(v0: i32):
                brz v0, ebb1
                jump ebb2
            ebb1:
                jump ebb3
            ebb2:
                brz v0, ebb4
                jump ebb5
            ebb3:
                jump ebb4
            ebb4:
                brz v0, ebb3
                brnz v0, ebb5
                jump ebb6
            ebb5:
                brz v0, ebb4
                trap user0
            ebb6:
                jump ebb7
            ebb7:
                return
        }
    ",
        vec![0, 2, 1, 3, 4, 6, 7, 5],
    );
}

#[test]
fn back_edge_one() {
    test_reverse_postorder_traversal(
        "
        function %test(i32) native {
            ebb0(v0: i32):
                brz v0, ebb1
                jump ebb2
            ebb1:
                jump ebb3
            ebb2:
                brz v0, ebb0
                jump ebb4
            ebb3:
                brz v0, ebb2
                brnz v0, ebb0
                return
            ebb4:
                trap user0
        }
    ",
        vec![0, 1, 3, 2, 4],
    );
}