Enabling static marker support in XULRunner

[Rajan Arora <rarora@redhat.com>]

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In continuation to the efforts on enabling packages with static dtrace
probe markers for use with Systemtap:
http://fedoraproject.org/wiki/Features/SystemtapStaticProbes , I
recently experimented with XULRunner. The SDK is used for building 
Firefox and enabling the available probe points in xulrunner will allow 
for high level tracing of firefox using systemtap. There is a bug report 
open for enabling this by default in Fedora Rawhide here:
https://bugzilla.redhat.com/show_bug.cgi?id=496113

Currently, XULRunner java-script source has some static markers that may 
be enabled with the reported patch. Attached is an example script that 
prints out the file and function names called when firefox runs a page 
with java script content in it. Here's some sample output: 
http://pastebin.com/f3b016c8c

For the example script to run, xulrunner build on that system should 
have static markers enabled, which enables Systemtap to gather such 
information.

Cheers
-Rajan


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# stap -v -c 'firefox some-javascript-page.html' example-xulrunner.stp 'libmozjs.so location'
# On a Fedora x86_64 box, 'libmozjs.so location' : /usr/lib64/xulrunner-1.9.1/libmozjs.so 

global funcinfo

probe begin
{
  printf ("Script displays File name, Function name and respective count...\n\n")
}

probe process(@1).mark("function__info")
{
  file = user_string ($arg1)
  func = user_string ($arg3)
  funcinfo[file,func] <<< 1
}

probe end
{
  foreach ([i,j] in funcinfo+)
  {
     printf ("%-75s %-35s %d\n", i, j, @count(funcinfo[i,j]))
  }
}