[pypy-dev] Information from the FlowObjSpace

Brian C. Lum bclum at cs.ucsd.edu
Thu Apr 13 08:14:50 CEST 2006


Thank you for the reply.  I have looked at model.py and I can make a 
FunctionGraph.  However, I am still not sure how to use it.

space = FlowObjSpace()
graph = space.build_flow(test.is_perfect_number)
fun = FunctionGraph(test.is_perfect_number, graph.startblock)

That is how I create an instance of FunctionGraph, and I can still make 
the blocks into an iterator, but I still cannot see what is inside the 
blocks, i.e. what would be the code in the function graph.

Basically, all I want is a flowgraph of the code so that I can try to 
perform some static analysis on it (I want to bound the length of lists at 
compile time).  I cannot figure out how to access the instructions in 
each basic block from the flowgraph.

Calling translate_as_module from pypy.translator.geninterplevel as 
described in 
http://codespeak.net/pypy/dist/pypy/doc/translation.html#example actually 
produces the SSA.  I was hoping that I would be able to get the 
instructions of each block from the flowgraph like in the example.


On Wed, 12 Apr 2006, Christian Tismer wrote:

> Brian C. Lum wrote:
>>  Dear Pypy developers:
>> I have gone through the source code for the FlowObjSpace in 
>> pypy.objspace.flow.objspace, but I am confused how to traverse through the 
>> blocks or obtain the information for each blocks in the graph.  From my 
>> understanding:
>> space = FlowObjSpace()
>> graph = space.build_flow(func)
>> Once you have the graph, however, how do you know what instructions are in 
>> each block?  I can iterate through the graph with iterblocks, but how do I 
>> get information from each block?
>> I want to analyze the information in each block to do code analysis for 
>> python.  Can anyone help me with this?
> First of all, flowing doesn't work for full CPython. You need
> to use the RPython subset (see 
> http://codespeak.net/pypy/dist/pypy/doc/coding-guide.html#restricted-python
> )
> Then, if you have a block, you can iterate over block.operations
> which is a list, and so on. See pypy/objspace/flow/model.py
> ciao - chris

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