If it is strictly for troubleshooting, why can't you include a console.log() in the controller JS like below?
If you need the caller for your business logic, then you can pass a parameter to the helper function and use it to conditionally do stuff.
Also, not sure if you are aware: You can determine the Global Id and Name of the component in context from within JS. Please see below for how-to.
Init Controller Method
doInit : function(component, event, helper) {
console.log('------------------> IN doInit NOW.');
helper.thatSingleHelperMethod(component, event, helper, 'doInit');
},
The Other Controller Method
someOtherControllerMethod : function(component, event, helper) {
console.log('------------------> IN someOtherControllerMethod NOW.');
helper.thatSingleHelperMethod(component, event, helper, 'someOtherControllerMethod');
}
Helper
thatSingleHelperMethod : function(component, event, helper, source) {
console.log('------------------> In thatSingleHelperMethod now.');
console.log('------------------> Source = ' + source);
var componentId = component.getGlobalId();
var componentName = component.getName().substring(1);
console.log('------------------> This Component Id = ' + componentId);
console.log('------------------> This Component Name = ' + componentName);
//Do Something based on source
}