FRCVLabMLSA_description < Main

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---++ How does it work?

<img src="%ATTACHURLPATH%/process_diagram.png" alt="process_diagram.png" width="1278" height="738" />

The process starts with C and Python source code from which separate ASTs (Abstract Syntax Tree) are dumped using Clang-Check (for C files)

<img src="%ATTACHURLPATH%/C_AST.jpeg" alt="C_AST.jpeg" width="951" height="121" />

Figure 1: Portion of a C AST file

and the AST module (for Python files). 

<img src="%ATTACHURLPATH%/PY_AST.jpeg" alt="PY_AST.jpeg" width="684" height="106" /> 

Figure 2: Portion of a Python AST file

The AST files have very different structures for C and Python, but the parsers are designed to handle each kind of AST differently. Those parsers filter the AST files detecting and recording function calls and their arguments. Initially, the program is capable of detecting literals and variables as arguments. Reaching Definition Analysis will be developed in the future in order to handle statically assigned variables as arguments to functions. The current version of the program handles part of the Python.h interface between C and Python. It only analyzes “PyRun_SimpleFile” calls. Other mechanisms for calling Python from C will also be implemented in the future.

When a call to “PyRun_SimpleFile” is found, its argument (name of the python file) is considered a function call and the executable portion of that python file is represented as the main function in C. That creates the connection between the C and the Python files, which allows the subsequent programs to build the call graph.

“CombineCSV.py” combines all individual csv files from the list of source files into one. This file is then used as input to “GenerateDot.py”. This program translates the csv file to a dot file, which represents the csv file as a graph. The Dot program builds the final graph and saves it as a PDF file. Circular nodes represent C functions and Rectangular nodes represent Python functions.


<img src="%ATTACHURLPATH%/callgraph.png" alt="callgraph.png" width="1006" height="566" />


Figure 3: Example of a multilingual call graph


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Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
jpeg	C_AST.jpeg	r1	manage	35.9 K	2016-07-27 - 14:46	DamianLyons
jpeg	PY_AST.jpeg	r1	manage	19.1 K	2016-07-27 - 14:46	DamianLyons
png	callgraph.png	r1	manage	39.2 K	2016-07-27 - 14:46	DamianLyons
png	process_diagram.png	r1	manage	43.9 K	2016-07-27 - 14:59	DamianLyons

This topic: Main > WebHome > FordhamRoboticsAndComputerVisionLaboratory > FRCVPublicProject > FRCVLabMLSA > FRCVLabMLSA_description
Topic revision: r2 - 2016-07-27 - BrunoVieiro