[Soot-list] Why create temp$xx variables?

[Peng Du]

Hello, experts

I have a newbie question about SOOT's IRs. Specifically, I have a simple
test program
on which I want to do some forward analysis via the Shimple IR. But I found
SOOT
would generate many temporary variables named "temp$XX", for each number
literal (e.g. 2, 3), and intermediate results. This was the case for both
Jimple and
Shimple. I know Jimple is 3-address based, but all the expressions involve
AT MOST
three variables as you can see in the program.

I wonder: Why is that?  Why we need those temp$ stuff? Can I eliminate that
without
turning on any optimizations or transformations? (I don't need them)  If
yes, how?

Thank you for looking.


Peng Du


Test program:
===========================================================
    public static int foo(boolean flag){
        int x, y, z;
        if (flag){
            x = 2; y = 3;
        }
        else {
            x = 3; y = 2;
        }
        z = x + y;
        return z;
    }
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Jimple
===========================================================
    public static int foo(boolean)
    {
        boolean flag;
        int x, y, z, temp$0, temp$1, temp$2, temp$3, temp$4, temp$5;

        flag := @parameter0: boolean;
        if flag == 0 goto label1;

        goto label0;

     label0:
        nop;
        temp$0 = 2;
        x = temp$0;
        temp$1 = 3;
        y = temp$1;
        goto label2;

     label1:
        nop;
        temp$2 = 3;
        x = temp$2;
        temp$3 = 2;
        y = temp$3;

     label2:
        nop;
        temp$4 = x;
        temp$5 = temp$4 + y;
        z = temp$5;
        return z;
    }
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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