Function test_island_backward

cranelift/codegen/src/machinst/buffer.rs:2737–2787

()

    #[test]
    fn test_island_backward() {
        let info = emit_info();
        let mut buf = MachBuffer::new();
        let mut state = <Inst as MachInstEmit>::State::default();
        let constants = Default::default();

        buf.reserve_labels_for_blocks(4);

        buf.bind_label(label(0), state.ctrl_plane_mut());
        let inst = Inst::Nop4;
        inst.emit(&mut buf, &info, &mut state);

        buf.bind_label(label(1), state.ctrl_plane_mut());
        let inst = Inst::Nop4;
        inst.emit(&mut buf, &info, &mut state);

        buf.bind_label(label(2), state.ctrl_plane_mut());
        while buf.cur_offset() < 2000000 {
            let inst = Inst::Nop4;
            inst.emit(&mut buf, &info, &mut state);
        }

        buf.bind_label(label(3), state.ctrl_plane_mut());
        let inst = Inst::CondBr {
            kind: CondBrKind::NotZero(xreg(0), OperandSize::Size64),
            taken: target(0),
            not_taken: target(1),
        };
        inst.emit(&mut buf, &info, &mut state);

        let buf = buf.finish(&constants, state.ctrl_plane_mut());

        assert_eq!(2000000 + 12, buf.total_size());

        let mut buf2 = MachBuffer::new();
        let mut state = Default::default();
        let inst = Inst::CondBr {
            kind: CondBrKind::NotZero(xreg(0), OperandSize::Size64),
            taken: BranchTarget::ResolvedOffset(8),
            not_taken: BranchTarget::ResolvedOffset(4 - (2000000 + 4)),
        };
        inst.emit(&mut buf2, &info, &mut state);
        let inst = Inst::Jump {
            dest: BranchTarget::ResolvedOffset(-(2000000 + 8)),
        };
        inst.emit(&mut buf2, &info, &mut state);

        let buf2 = buf2.finish(&constants, state.ctrl_plane_mut());

        assert_eq!(&buf.data[2000000..], &buf2.data[..]);
    }

    #[test]
    fn test_multiple_redirect() {