Need to analyze C source code and determine loops (program analysis)
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From: lonewolf on 8 Dec 2009 08:45 For our project, we need to analyze C source code (our input) and determine where or not a for loop exists (so we can add OpenMP directives beforehand if it will help). How would you recommend we do this? Our current approach is a string parser but we do not know in detail better approaches that might exist such as syntax trees, etc. Any available libraries? Thanks -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Ira Baxter on 9 Dec 2009 12:38 "lonewolf" <jon.sero(a)gmail.com> wrote in message news:fc2201c7-331d-44fc-ae98-db33151ff5c7(a)j4g2000yqe.googlegroups.com... > For our project, we need to analyze C source code (our input) and > determine where or not a for loop exists (so we can add OpenMP > directives beforehand if it will help). How would you recommend we do > this? Our current approach is a string parser but we do not know in > detail better approaches that might exist such as syntax trees, etc. > Any available libraries? "String parsers" are an extremely unreliable way to analyze program source code. The DMS Software Reengineering Toolkit is a program transformation system with C and C++ front ends for many dialects of these languages, including GCC. It can be used to parse C or C++ code to abstract syntax trees, carry out arbitrary analyses and transformations on the code,. and regenerate compilable source code complete with comments. See http://www.semanticdesigns.com/Products/DMS/DMSToolkit.html It has been used to analyze and transform very large source code bases automatically. Transformations are stated as a mixture of source-to-source rewrite rules ("if you see <this syntax>, replace it by <that syntax>") and procedural transforms (change the abstract syntax tree directly), each conditioned on some applicability analysis. These could be used to insert OpenMP directives. See http://www.semanticdesigns.com/Products/DMS/ProgramTransformations.html for background on source-to-source transformations. While it would be very easy to use the rewrite rule patterns to represent so-called looping constructs ("for", "while", ..) often the language syntax for loops is misleading. One can construct loops with gotos, for instance, and one can unconditionally goto out of a loop in the middle making it not-a-loop. DMS provides control and data flow analysis for C programs; the control flow analysis determines what the the actual control flow is and makes that available to drive the transformations. Check out the discussion on flow analysis at http://www.semanticdesigns.com/Products/DMS/FlowAnalysis.html. DMS is designed to carry out automated program changes. -- Ira Baxter, CTO www.semanticdesigns.com [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ]
From: Frank Birbacher on 9 Dec 2009 12:41
Hi! lonewolf schrieb: > Our current approach is a string parser but we do not know in > detail better approaches that might exist such as syntax trees, etc. for loops are detected by searching for the keyword "for". There is a program "grep" which does this http://unixhelp.ed.ac.uk/CGI/man-cgi?grep In order to ignore comments in the source and in order to detect loops generated by marcos you should run the c++ preprocessor. gcc has a mode which does this (compiler option -E). The preprocessed output will contain hints to find source file and line for any loop. Frank -- [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] |