μJS static analyzer is a static analyzer based on abstract interpretation for μJs, a sub-language of JavaScript. Its syntax is reported in figure above.

git clone https://github.com/SPY-Lab/mu-js

Here you can find the JAR file mujs.jar and you can run the μJS static analyzer as

java -jar mujs.jar filename.js 

Some option are available:

• -widening n: set the parametric widening to n;
• -narr: enables narrowing operation. By default, narrowing is not applied;
• -coalesced: choose the coalesced sum abstract domain for the analysis. By default, this domain is used during the analysis;
• -lifted: choose the lifted union abstract domain for the analysis;
• -invariants: prints the invariants for each statement program point. By default, it prints only the memory holding at the end of the abstract execution;
• -help: print the menu.

Consider the following μJS program.

str = "helloworld";
a = 0;

while (a < 100) {
	a = a + 1;
}

if (a == 5) {
	c = (str.charAt(0));
} else {
	c = (str.charAt(3));
}

The state resulting from `java -jar -coalesced mujs.jar file.js is

*******************
str -> helloworld
a -> [0, +Inf]
c -> (l + h)
*******************

• Vincenzo Arceri [email protected]
• Isabella Mastroeni [email protected]