An initiative towards introducing Static Code Analysis for Scala Programs.

1. Static Analysis of Scala ProgramsStatic Analysis of Scala Programs
Himanshu Gupta
Knoldus Software LLP
Himanshu Gupta
Knoldus Software LLP

2. Topics CoveredTopics Covered
Overview
Motivation
Advantages
Disadvantages
Live Demo
Overview
Motivation
Advantages
Disadvantages
Live Demo

3. Static Analysis: Overview
● Static
– Performed at compile time, i.e., without executing the program
● Analysis
– Determination of interesting properties of the run-time behavior of the
program
● The goal is to
– Enable optimizations
– Find bugs, test, debug, ....

4. Static Analysis: Motivation ─
Optimization
The optimization:
x = 1 y = 1
y = x
is unsound if x is used in a later instruction:
x = 1
y = x y = 1
... ...
z = x z = x

5. Static Analysis: Motivation ─
Checking for Unreachable Code
def foo(x: Int): Int = { def bar(b: Boolean) {
return x if (b) { return }
x = x + 1 else { return }
x = x – 1 return
} }
We’d like to notify users about the above “ill-
formed” code.

6. Static Analysis: Motivation ─
Checking for Unused Vars.
def foo() = {
val x = 0
val y = 1
bar(y)
}
We’d like to notify users about the above
ill-formed code

7. Where to Perform Analysis?
● Static analysis may take place:
– at the source code level;
– at some intermediate level; or
– at the machine code level.
●
Static analysis may look at:
– basic blocks only;
– an entire function (intraprocedural); or
– the whole program (interprocedural).
●
The precision and cost of an analysis rises as we include more
information.

8. Advantages
● Makes Programs more efficient in terms of both,
Memory & Time.
● Increases the quality & reliability of code.
● Reduces the time spent by developers in tedious jobs
like regression testing, debugging, etc.
● Helps in developing platform independent S/Ws.

9. Disadvantages
● Extra effort has to be put to Static Analyzers for a
particular S/W.
● Increases the cost of development.
● Different tools for different languages and platforms.
– Eg :- Soot (for JVM based static code analysis only)

10. Live Demo
To run this Demo, follow these steps: -
1. Install Soot by following steps given on website
http://www.sable.mcgill.ca/soot/eclipse/updates/
2. Import Soot Libraries in your project by configuring Build Path
3. Download this project from :-
https://github.com/gupta-himanshu/static-analysis-scala
4. Run it as Java Application

11. ThanksThanks