For this assignment, you will create a standalone program named graph in python$/$c$/$cpp$.$ The code should be substantially your own. Although you may use auxiliary libraries, the fundamental tasks described must be performed by code you wrote for this assignment. The analysis program will perform some basic analysis over an input file in a restricted subset of LLVM$.$ In particular, the only pseudoinstructions that you need to cover are:

alloca

getelementpointer

load

store

ret

icmp

br

add

sub

div

mul

phi

call

define

Additionally, your analysis should accomodate programs with both global and local variable allocations. You may assume that all variables are of scalar integer type.

Assignment Details: This assignment consists of CFG inference, i$.$e$.$ inducing a control$-$flow graph over an input. The basic idea of is to construct the control$-$flow graph of each function declared in a given input file and output those control$-$flow graphs in the graphviz dot format. For each function in the input, the program will output a graphviz control$-$flow graph. The nodes should have record shape. It is sufficient to simply output the correct structure of the CFG with the correct edge labels. Edges should be directed and have a label according to their position in the branch, starting at index $0.$ For example, consider the input:

Example $1$ Input:

define i$32$ @main$($i$32\%$argc$)\{$

$\%$noArgs $=$ icmp eq i$32\%$argc, $1$

br i$1\%$noArgs, label $\%$lbl$\_$t$,$ label $\%$lbl$\_$f

lbl$\_$t:

$\%$varT $=$ add i$321,0$

br label $\%$end

lbl$\_$f:

$\%$varF $=$ add i$322,0$

br label $\%$end

end:

$\%$var $=$ phi i$32[\%$varT, $\%$lbl$\_$t$],[\%$varF, $\%$lbl$\_$f$]$

ret i$32\%$var

$\}$

The output would be of the form

Example $1$ Output:

digraph $\{$

Node$0[$shape$=$record,label$=""]$

Node$0->$ Node$1[$label$=0]$;

Node$0->$ Node$2[$label$=1]$;

Node$1[$shape$=$record,label$=""]$

Node$1->$ Node$3[$label$=0]$;

Node$2[$shape$=$record,label$=""]$

Node$2->$ Node$3[$label$=0]$;

Node$3[$shape$=$record,label$=""]$

$\}$

Note that for this behavior to be correct, the output must be valid in the dot format. Your code should be able to be tested with the following sequence of commands on the cycle servers:

tar $-$xf P$2.$tgz

cd P$2$

make

$./$graph test$1.$ll

dot main.dot $-$o main.png $-$Tpng

where test$1.$ll is a file containing a main function.

As described above, you may use any coding language of your choice to complete this assignment. However, the above sequence of commands must work without error. For example, if you are using python, you might include a Makefile that immediately exits $0($since there is no code to build$).$ Furthermore, you should either include a helper script named graph that launches the python interpreter with its argument.