CFG-Language-Processor-And-Compiler: A C++ repository from devendrachaplot

cfglp : A CFG Language Processor
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About:
Implemented by Uday Khedker (http://www.cse.iitb.ac.in/~uday) for
the courses cs302+cs306: Language Processors (theory and lab) at
IIT Bombay. Release date Jan 6, 2013. Copyrights reserved by Uday
Khedker. This implemenation has been made available purely for
academic purposes without any warranty of any kind.

A doxygen generated documentation can be found at
http://www.cse.iitb.ac.in/~uday/cfglp
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This is a language processor that

- takes as input GCC tree-cfg (control flow graph) dumps and
- either interprets them or compiles them into spim assembly based
on a command line parameters.

The complete functionality supported by cfglp is best described by the usage printed by it:

Usage: cfglp [options] [file]
Options:
-help Show this help
-tokens Show the tokens in file.toks (or out.toks)
-ast Show abstract syntax trees in file.ast (or out.ast)
-symtab Show the symbol table of declarations in file.sym (or out.sym)
-program Show the complete program read by cfglp in file.prog (or out.prog)
(-program option cannot be given with -tokens, -ast, or -symtab)
-eval Interpret the program and show a trace of the execution in file.eval (or out.eval)
-compile Compile the program and generate spim code in file.spim (or out.spim)
(-eval and -compile options are mutually exclusive)
(-compile is the default option)
-lra Do local register allocation to avoid redundant loads within a basic block
-icode Compile the program and show the intermediate code in file.ic (or out.ic)
(-eval and -icode options are mutually exclusive)
-d Demo version. Use stdout for the outputs instead of files

At the moment cfglp accepts level 0 language that defines simple cfgs corresponding to
programs that contain

- only integer variables and numbers,
- only assignment statements, no control flow, no function calls
- the right hand sides of the assignments can only be a scalar variable or a number
- the main function does not return any value.

Please see the files p1, p2, p3, and p4 for the examples of valid and invalid inputs.

The subsequent versions would enhance the input language incrementally as follows:

- Level 1: Allow floating point numbers and common arithmetic operations on the right hand
side. The expectation is that the temporary variables introduced by GCC are
eliminated and larger ASTs are created for right hand sides.
- Level 2: Allow control flow statements and evaluation of conditions.
- Level 3: Allow function calls (including recursion).
- Level 3: Allow data and procedure encapsulation supported by classes.

The cfglp embodies object oriented design and implementation. The implementation language is
C++. The main classes that constitute cfglp are:

- program, procedure, basic block, abstract syntax trees
- symbol table (persistent as well as volatile symbol table for scope analysis
- register and instruction descriptor
- intermediate code

The methods of these classes have been divided into file names with a suffix that represent
the overall functionality eg. for ASTs, the classes are defined in ast.hh where as the methods
are implemented in the files ast-build.cc, ast-print.cc, ast-typecheck.cc, ast-evaluate.cc,
and ast-compile.cc.

This implementation has the following dependencies:

- It requires bison 2.7 (earlier versions do not support named attributes).
- It requires flex 2.5 or higher.
- It requires a contemporary g++ compiler.

The dependencies for input and output are:
- It accepts cfg dumps produced by GCC-4.4.3 or later. GCC by default does not dump global
declarations so we need a dynamic plugin (provided separately) for program that contain
global variables.
- The compiled assembly program can be executed on the spim simulator of MIPs.

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Dr. Uday Khedker
Professor
Department of Computer Science & Engg.
IIT Bombay, Powai, Mumbai 400 076, India.
Email : uday@cse.iitb.ac.in
Homepage: http://www.cse.iitb.ac.in/~uday
Phone :
Office - 91 (22) 2572 2545 x 7717, 91 (22) 2576 7717 (Direct)
Res. - 91 (22) 2572 2545 x 8717, 91 (22) 2576 8717 (Direct)

devendrachaplot/CFG-Language-Processor-And-Compiler