Difference between revisions of "Gecko:Debugging Tools"

From MozillaWiki
Jump to: navigation, search
(→‎Frame Tree Dump: add link to a page with documentation on layout debugger)
 
(7 intermediate revisions by 2 users not shown)
Line 2: Line 2:
  
 
[http://web.mit.edu/bzbarsky/www/gdbinit bz's gdbinit]
 
[http://web.mit.edu/bzbarsky/www/gdbinit bz's gdbinit]
 +
 +
== GDB pretty printers ==
 +
 +
[http://hg.mozilla.org/users/jblandy_mozilla.com/archer-mozilla/ JS-specific printers]
 +
 +
[http://hg.mozilla.org/users/josh_joshmatthews.net/archer-mozilla/ General gecko printers]
  
 
== Printing arrays ==
 
== Printing arrays ==
 +
 +
define ptarray
 +
        if $argc == 0
 +
                help ptarray
 +
        else
 +
                set $size = $arg0.mHdr->mLength
 +
                set $capacity = $arg0.mHdr->mCapacity
 +
                set $size_max = $size - 1
 +
                set $elts = $arg0.Elements()
 +
        end
 +
        if $argc == 1
 +
                set $i = 0
 +
                while $i < $size
 +
                        printf "elem[%u]: ", $i
 +
                        p *($elts + $i)
 +
                        set $i++
 +
                end
 +
        end
 +
        if $argc == 2
 +
                set $idx = $arg1
 +
                if $idx < 0 || $idx > $size_max
 +
                        printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
 +
                else
 +
                        printf "elem[%u]: ", $idx
 +
                        p *($elts + $idx)
 +
                end
 +
        end
 +
        if $argc == 3
 +
          set $start_idx = $arg1
 +
          set $stop_idx = $arg2
 +
          if $start_idx > $stop_idx
 +
            set $tmp_idx = $start_idx
 +
            set $start_idx = $stop_idx
 +
            set $stop_idx = $tmp_idx
 +
          end
 +
          if $start_idx < 0 || $stop_idx < 0 || $start_idx > $size_max || $stop_idx > $size_max
 +
            printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
 +
          else
 +
            set $i = $start_idx
 +
                while $i <= $stop_idx
 +
                        printf "elem[%u]: ", $i
 +
                        p *($elts + $i)
 +
                        set $i++
 +
                end
 +
          end
 +
        end
 +
        if $argc > 0
 +
                printf "nsTArray length = %u\n", $size
 +
                printf "nsTArray capacity = %u\n", $capacity
 +
                printf "Element "
 +
                whatis *$elts
 +
        end
 +
end
  
 
[http://blog.mozilla.com/cjones/2010/04/30/print-nstarrays-in-gdb/ Chris Jones' handy ptarray command]
 
[http://blog.mozilla.com/cjones/2010/04/30/print-nstarrays-in-gdb/ Chris Jones' handy ptarray command]
Line 9: Line 68:
 
== Frame Tree Dump ==
 
== 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
+
<bz> for a frame dump, you can use the [https://developer.mozilla.org/en-US/docs/Mozilla/Debugging/Layout_Debugger layout debugger], or... if you're in a debugger and want to examine the tree, you can do
  
 
  def frametree
 
  def frametree
−
   set $r = ($arg0)->PresContext()->GetPresShell()->GetRootFrame()
+
   call nsFrame::DumpFrameTree($arg0)
−
  if ($r)
 
−
    call ((class nsIFrameDebug*)(class ViewportFrame*)$r)->List(stderr, 2)
 
−
  end
 
 
  end
 
  end
  
Line 23: Line 79:
 
== Printing nsIAtoms ==
 
== 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
+
def pa
 +
  set $atom = $arg0
 +
  if (sizeof(*((&*$atom)->mString)) == 2)
 +
    pu (&*$atom)->mString
 +
  end
 +
end
  
−
<bz> if it's an nsStaticAtom:
+
== Reflow Logs ==
  
−
  def satom
+
See [[http://www.mozilla.org/newlayout/doc/frame_reflow_debug.html Debugging Frame Reflow]]
−
    p *((class nsStaticAtomWrapper*)$arg0)->mStaticAtom
+
 
−
  end
+
== Printing strings ==
  
−
<bz> to be used as: ''satom content->Tag()'' or ''satom frame->GetType()''
+
# Define a "ps" command to display subclasses of nsAC?String.  Note that
 +
# this assumes strings as of Gecko 1.9 (well, and probably a few
 +
# releases before that as well); going back far enough will get you
 +
# to string classes that this function doesn't work for.
 +
def ps
 +
  set $str = $arg0
 +
  if (sizeof(*$str.mData) == 1 && ($str.mFlags & 1) != 0)
 +
    print $str.mData
 +
  else
 +
    pu $str.mData $str.mLength
 +
  end
 +
end
  
−
<bz> for nsGkAtoms it'll work great
+
# Define a "pu" command to display PRUnichar * strings (100 chars max)
 +
# Also allows an optional argument for how many chars to print as long as
 +
# it's less than 100.
 +
def pu
 +
  set $uni = $arg0
 +
  if $argc == 2
 +
    set $limit = $arg1
 +
    if $limit > 100
 +
      set $limit = 100
 +
    end
 +
  else
 +
    set $limit = 100
 +
  end
 +
  # scratch array with space for 100 chars plus null terminator.  Make
 +
  # sure to not use ' ' as the char so this copy/pastes well.
 +
  set $scratch = "____________________________________________________________________________________________________"
 +
  set $i = 0
 +
  set $scratch_idx = 0
 +
  while (*$uni && $i++ < $limit)
 +
    if (*$uni < 0x80)
 +
      set $scratch[$scratch_idx++] = *(char*)$uni++
 +
    else
 +
      if ($scratch_idx > 0)
 +
set $scratch[$scratch_idx] = '\0'
 +
print $scratch
 +
set $scratch_idx = 0
 +
      end
 +
      print /x *(short*)$uni++
 +
    end
 +
  end
 +
  if ($scratch_idx > 0)
 +
    set $scratch[$scratch_idx] = '\0'
 +
    print $scratch
 +
  end
 +
end
  
−
== Reflow Logs ==
+
== Dumping the JS Stack ==
  
−
See [[http://www.mozilla.org/newlayout/doc/frame_reflow_debug.html Debugging Frame Reflow]]
+
def js
 +
  call DumpJSStack()
 +
end

Latest revision as of 20:11, 15 March 2019

.gdbinit

bz's gdbinit

GDB pretty printers

JS-specific printers

General gecko printers

Printing arrays

define ptarray
       if $argc == 0
               help ptarray
       else
               set $size = $arg0.mHdr->mLength
               set $capacity = $arg0.mHdr->mCapacity
               set $size_max = $size - 1
               set $elts = $arg0.Elements()
       end
       if $argc == 1
               set $i = 0
               while $i < $size
                       printf "elem[%u]: ", $i
                       p *($elts + $i)
                       set $i++
               end
       end
       if $argc == 2
               set $idx = $arg1
               if $idx < 0 || $idx > $size_max
                       printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
               else
                       printf "elem[%u]: ", $idx
                       p *($elts + $idx)
               end
       end
       if $argc == 3
         set $start_idx = $arg1
         set $stop_idx = $arg2
         if $start_idx > $stop_idx
           set $tmp_idx = $start_idx
           set $start_idx = $stop_idx
           set $stop_idx = $tmp_idx
         end
         if $start_idx < 0 || $stop_idx < 0 || $start_idx > $size_max || $stop_idx > $size_max
           printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
         else
           set $i = $start_idx
               while $i <= $stop_idx
                       printf "elem[%u]: ", $i
                       p *($elts + $i)
                       set $i++
               end
         end
       end
       if $argc > 0
               printf "nsTArray length = %u\n", $size
               printf "nsTArray capacity = %u\n", $capacity
               printf "Element "
               whatis *$elts
       end
end

Chris Jones' handy ptarray command

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
  call nsFrame::DumpFrameTree($arg0)
end


<bz> That should work when called on any nsIFrame to dump the tree it belongs to

Printing nsIAtoms

def pa
  set $atom = $arg0
  if (sizeof(*((&*$atom)->mString)) == 2)
    pu (&*$atom)->mString
  end
end

Reflow Logs

See [Debugging Frame Reflow]

Printing strings

# Define a "ps" command to display subclasses of nsAC?String.  Note that
# this assumes strings as of Gecko 1.9 (well, and probably a few
# releases before that as well); going back far enough will get you
# to string classes that this function doesn't work for.
def ps
  set $str = $arg0
  if (sizeof(*$str.mData) == 1 && ($str.mFlags & 1) != 0)
    print $str.mData
  else
    pu $str.mData $str.mLength
  end
end

# Define a "pu" command to display PRUnichar * strings (100 chars max)
# Also allows an optional argument for how many chars to print as long as
# it's less than 100.
def pu
 set $uni = $arg0
 if $argc == 2
   set $limit = $arg1
   if $limit > 100
     set $limit = 100
   end
 else
   set $limit = 100
 end
 # scratch array with space for 100 chars plus null terminator.  Make
 # sure to not use ' ' as the char so this copy/pastes well.
 set $scratch = "____________________________________________________________________________________________________"
 set $i = 0
 set $scratch_idx = 0
 while (*$uni && $i++ < $limit)
   if (*$uni < 0x80)
     set $scratch[$scratch_idx++] = *(char*)$uni++
   else
     if ($scratch_idx > 0)

set $scratch[$scratch_idx] = '\0' print $scratch set $scratch_idx = 0 

     end
     print /x *(short*)$uni++
   end
 end
 if ($scratch_idx > 0)
   set $scratch[$scratch_idx] = '\0'
   print $scratch
 end
end

Dumping the JS Stack

def js
  call DumpJSStack()
end
Retrieved from "https://wiki.mozilla.org/index.php?title=Gecko:Debugging_Tools&oldid=1209012"