Python

The purpose of the python module is to embed the python interpreter and wrap the jitdata structure to make it possible to write experimental passes rapidly in python.

A very brief example of a function that orders basic blocks in post order and displays their numbers. Let's suppose it's located in a file foo.py.

   1 class post_order:
   2     def __init__(self):
   3         self.marked = { }
   4     def __call__(self, bb):
   5         if self.marked.has_key(bb):
   6             return [ ]
   7         else:
   8             self.marked[bb] = True
   9             return sum([ self(succ) for succ in bb.successors], []) + [ bb ]
  10 def display_post_order(jd):
  11     print "----[", jd.method.klass.name, jd.method.name, "]----"
  12     po = post_order()
  13     po = po(jd.basic_blocks[0])
  14     print [b.nr for b in po]

To call it from C:

pythonpass_run(jd, "foo.py", "display_post_order");

An example that renders the control flow graph using dot and displays it:

   1 def cfg(jd):
   2     f = open("/tmp/x.dot", "w")
   3 
   4     print >> f, "digraph g {"
   5 
   6     for b in jd.basic_blocks:
   7 
   8         attrs = []
   9 
  10         if b.exception_handler:
  11             attrs.append(('color', 'red'))
  12 
  13         print >> f, b, '[', ','.join([ '%s="%s"' % attr for attr in attrs ]), '];'
  14 
  15     for b in jd.basic_blocks:
  16         for s in b.successors:
  17             print >> f,  b, "->", s, ";"
  18         for p in b.predecessors:
  19             print >> f, p, "->", b, ";"
  20 
  21     print >> f, "};"
  22 
  23     f.close()
  24 
  25     import os
  26     os.system("dot -Tpng /tmp/x.dot -o /tmp/x.png")
  27     os.system("kuickshow /tmp/x.png")