Gecko:Debugging Tools
From MozillaWiki
.gdbinit
Frame Tree Dump
<bz> for a frame dump, you can use the layout debugger, or... if you're in a debugger and want to examine the tree, you can do
def frametree set $r = ($arg0)->PresContext()->GetPresShell()->GetRootFrame() if ($r) call ((class nsIFrameDebug*)(class ViewportFrame*)$r)->List(stderr, 2) end end
<bz> That should work when called on any nsIFrame to dump the tree it belongs to
Printing nsIAtoms
<bz> To print an nsIAtom, you see what concrete type it is using "set print object on", then cast it to that type, etc
<bz> if it's an nsStaticAtom:
def satom p *((class nsStaticAtomWrapper*)$arg0)->mStaticAtom end
<bz> to be used as: satom content->Tag() or satom frame->GetType()
<bz> for nsGkAtoms it'll work great
Reflow Logs
See [Debugging Frame Reflow]