title: does gdb has something similar to struct command of crash utility
body: <p>I want to dump the internal data structures of ovs-vswitchd.</p>
  
  <pre><code>(gdb) print/x all_dpif_backers
  $11 = {
      map = {
          buckets = 0x7e0e28,
          one = 0x23467f0,
          mask = 0x0,
          n = 0x1
      }
  }
  </code></pre>
  
  <p>Now I know 0x23467f0 is the address of struct hmap_node.  If using crash
  utility, I can dump the value like this:
  crash> struct hmap_node 0x23467f0
  How can we do this using gdb?</p>