dmholtz / dynamicprogramslicing Goto Github PK

Test string methods

• in ReturnStatement
• in code (as part of normal execution)

If the consequent node of an IfStatement is null, the trimmer crashes.

Example (in case only line 1 is included in the slice and line 2 should be excluded):

if (x>0)
    x++;

The slicer produces wrong results, if implicit uses of object attributes occur.

If the slicing criterion is of type object, all of its attributes are implicitly accessed. However, the current implementation does not reflect this implicit behaviour and produces an incorrect slice.

Example: testcases/progress2/e2_in.js (here simplified):

function sliceMe() {
    var a = { course: 'Program Analysis' };
    a.semester = 'Winter';
    return a; // slicing criterion
}
sliceMe();

Expected slice:

function sliceMe() {
    var a = { course: 'Program Analysis' };
    a.semester = 'Winter';
    return a; // slicing criterion
}
sliceMe();

However, the analysis does not include the putField statement of line 3 and computes a wrong slice:

function sliceMe() {
    var a = { course: 'Program Analysis' };
    return a; // slicing criterion
}
sliceMe();

Yet, all branching points are tracked even if both ways are not included in the slice.

Example:

function sliceMe() {
    var x = 0;
    var y = 1;
    if (y) {
        y++;
    }
    else {
        y--;
    }
    return x;
}
sliceMe();

The predicted slice is: Note that the branching points remains and even data dependencies are further propagated, which are not relevant for computing the slice:

function sliceMe() {
    var x = 0;
    var y = 1;
    if (y) {
    }
    return x;
}
sliceMe();

However, the ideal slice is:

function sliceMe() {
    var x = 0;
    return x;
}
sliceMe();

Including delete, typeof

Especially the lazy evaluation of && and || to avoid conflicts with branching.

This issue has two effects:

Syntactical issue: The discriminant node is not included in the AST, as there is no callback which adds the line of switch (...) to the keepLines set in the dataflow-analysis.js script

Semantical isuuse: Data dependencies of the discriminant node are not tracked either.

Includes throws, tryand single and multiple uses of catch and finally

Given a program like, which is called with x=1:

switch(x) {
  case 0: // refused case, but callback was triggered
    bar();
    break;
  case 1: // refused case, but callback was triggered
  case 2: // callback was NOT triggered
     foo(); // slicing criterion
     break;
}

The slicer does not exclude case 0.

Given a JS program like

var x = 9;
x = 10;
console.log(x); // slicing criterion

Should the unnecessary define in line 1 be included?

var x = 9;
x = 10;
console.log(x); // slicing criterion

or instead removed?

var x;
x = 10;
console.log(x); // slicing criterion

Initialization of Arrays and the use of methods, which do not change the array, e.g. lastIndexOf

do-while

Use a built-in class such as Date

The breakstatement is not included in the slice.

Jalangi does not provide any callbacks for explicitly handling break statements.