When I first arrived, one of the things that amazed me was how aware Spain is with Coeliac Disease. Almost everything gluten free is clearly listed on the packet 'Sin Gluten', meaning no gluten, so you could feel completely confident in what you were buying.
We were staying in Esquerra d'Eixample which had local markets near by, and a health food shop. I bought chocolate rice cakes to snack on (demolish).
And gluten free cones!
We spent the majority of the weekend munching through huge amounts of Paella, Patatas Bravas and various seafood dishes, not to mention the many glasses of Sangria. I avoided the obvious things that I knew would contain gluten, and felt absolutely fine the whole weekend.
We also stumbled across a sweet shop with clearly labeled pick 'n' mix.
The one place I did have difficulty was the airport on the way home. I recommend either eating before or taking a snack with you, as evan the rice salads they had at a coffee shop had 'may contain gluten' written on the back.
Overall though, an exceptional trip, with no stressful/anxious eating situations. If you were ever hungry there was always going to be something you could eat.
Maybe I will move there one day, I just need to expand my non existent Spanish vocab.