Srirangam temple has been a mute witness to so many things. The temple we see now was built stage by stage - over a period of 2000 years. Only the garbagraha and a small mandapa was there for a very long time. Also, Dr. Kalaikkovan told us that it is this temple that contains max no of inscriptions that any other temple in TN. Roughly 600 inscriptions !! When you go next time, go to a small temple of vishvaksenar or senai mudhaliyar near kili mandapam and Sri padham of lord.
The architectural style of this small temple is very much a style of early chola - Aditya / parantaka days. I had visited the temple many times but found this out only last time. You can easily compare this small temple with Koranganatha temple (Srinivasa nallur) and other pre-Rajaraja temples.
Thus, the contributions to temple start even before raaja mahendra chola, even before RR. The association of srirangam with cholas is very old:
Dharmavarma - who excavates the temple in cauvery bed (may be pre sangam or sangam period) - is a chola
The oldest reference to the temple is silappathikaram
Nandha chozha - who gives her daughter sengamalavalli (uraiyur temple) to ranganatha - is a chola and belongs to dharmavarma race
I'm sure kochchenganan might have visited the temple.
Then aditya - parantaka - Rajaraja (??) - raja mahendra etc
Dr.Kalai mentioned about a doctoral work on srirangam temple history. He has the book. I forgot to take a copy last time - you may get it from him.