Getting EXC_BAD_ACCESS while the object exists - ios

Question

I'm developing a music sequencer with a standard piano roll type UI.
It was working well until I made some changes in the model side but it suddenly started to report EXC_BAD_ACCESS at (seemingly) unrelated part.
What's strange is all the necessary variables have their values properly and actually I can print values with po.
In my understanding, EXC_BAD_ACCESS happens when an object doesn't exist, so this seems quite strange.
My question is:
Is it common to EXC_BAD_ACCESS even the values are there?
If that's the case what is the possible situation to cause that?
Any suggestion is helpful. Thanks
[Below are the codes]
In my subclass of UICollectionViewLayout:
override func layoutAttributesForElements(in rect: CGRect) -> [UICollectionViewLayoutAttributes]? {
// note cells
let cv = self.collectionView as! YMPianoRollCollectionView;
let pianoRoll = cv.pianoRollViewController;
// Call the below func to get the indexes of the Note Objects included in the specified rect
let indexArray: Array<Int> = pianoRoll!.getNoteIndexes(inRect:rect, useOnlyStartTime: false);
var retArray : [UICollectionViewLayoutAttributes] = []
for i in indexArray {
if let _ = pianoRoll?.pattern.eventSequence[i] as? YMPatternEventNoteOn {
retArray.append( self.layoutAttributesForPatternEventInfo(i) )
}
}
return retArray
}
In my "piano roll" class which contains UICollectionView
func getNoteIndexes(inRect rect:CGRect, useOnlyStartTime: Bool) -> Array<Int> {
//
// Transform given values into musical values
//
let musicRange :YMMusicalValueRange = screenInfo.getMusicalRange(rect);
let startTime = musicRange.origin.time;
let endTime = musicRange.origin.time + musicRange.size.timeLength;
let lowNoteU = musicRange.origin.noteNumber;
let highNoteU = musicRange.origin.noteNumber + musicRange.size.numberOfNotes;
var retArray : [Int] = []
for i in 0..<pattern.eventSequence.count {
if let e = pattern.eventSequence[i] as? YMPatternEventNoteOn {
//
// Prepare ranges
//
let noteNo = e.noteNo; //<- App Crashes Here with BAD_ACCESS
let noteStTime = e.time;
let noteEnTime = e.time + e.duration;
let targetNoteRange = Range<Int>(uncheckedBounds: (lowNoteU, highNoteU));
let targetTimeRange = Range<Int64>(uncheckedBounds: (startTime, endTime))
let noteTimeRange = Range<Int64>(uncheckedBounds: (noteStTime, noteEnTime))
//
// Check the match
//
let noteMatches = targetNoteRange.contains(noteNo);
let timeMatches = useOnlyStartTime ? targetTimeRange.contains(noteStTime)
: targetTimeRange.overlaps(noteTimeRange)
if noteMatches && timeMatches {
retArray.append( i );
NSLog("XXX Found: note \(noteNo) at \(e.time)");
}
}
}
return retArray;
}
Error:- The object states when it crashed
EDIT
Here's the YMPatternEventNoteOn declaration
class YMPatternEvent : Codable, CustomDebugStringConvertible {
var time : YMSequenceTime = 0
// Some utility funcs follow
// ...
}
class YMPatternEventNoteOn : YMPatternEvent {
var noteNo : Int = 64
var velocity : Int = 127
var duration : YMSequenceTime = 480
var tempBendId : Int = 0;
var tempVibratoId : Int = 0;
var tempArpeggioId : Int = 0;
convenience init(time :YMSequenceTime, noteNo : Int, velocity: Int, duration: YMSequenceTime) {
self.init();
self.time = time;
self.noteNo = noteNo;
self.velocity = velocity;
self.duration = duration;
}
// Other methods follow
// ...
}
EDIT2
Note event is created by the user's action
//
// In YMPattern object
//
func insertNote(time:YMSequenceTime, noteNo:Int, velocity:Int, duration:YMSequenceTime) -> Int
{
let onEvent = YMPatternEventNoteOn(time: time, noteNo: noteNo, velocity: velocity, duration: duration);
let retIndex = insertEvent(onEvent);
return retIndex;
}
func insertEvent(_ event: YMPatternEvent) -> Int {
let atTime = event.time;
var retIndex : Int = 0;
if(eventSequence.count<1){
// If it's the first event just add it
eventSequence.append(event);
retIndex = 0;
} else {
// If any event already exists, insert with time order in consideration
var i : Int = 0;
while( atTime > eventSequence[i].time ){
i += 1;
if( i >= eventSequence.count ){
break;
}
}
retIndex = i;
eventSequence.insert(event, at: i)
}
}
//
// In pianoroll view controller
//
func actionButtonReleased(afterDragging: Bool) {
let values:YMMusicalValuePoint = screenInfo.getMusicalPosition(cursorPosition);
// insert new event with default velocity and duration
let _ = pattern.insertNote(time: values.time, noteNo: values.noteNumber, velocity: 127, duration: screenInfo.timeTicsPerDivision());
collectionView.reloadData();
}

Answer 1

I've solved it in a way.
By setting the optimization level to "Whole Module Optimization" it stopped reporting the error.
I don't know what is happening internally but if someone is having the same issue, this might work as a quick fix.