addRow

    pub fn addRow(prog: *LineNumberProgram, gpa: Allocator, table: *CompileUnit.SrcLocCache.LineTable) !void {
        if (prog.line == 0) {
            //if (debug_debug_mode) @panic("garbage line data");
            return;
        }
        if (debug_debug_mode) assert(!table.contains(prog.address));
        try table.put(gpa, prog.address, .{
            .line = cast(u32, prog.line) orelse maxInt(u32),
            .column = cast(u32, prog.column) orelse maxInt(u32),
            .file = cast(u32, prog.file) orelse return bad(),
        });
    }